Database: EMBASE <: international biomedical and pharmaceutical literature, 1988 - May 2000. [Trial access until 3/2001. Feedback welcome to medical.library@umich.edu] Search Strategy (You Saved Citations 1-284 From Set 63): ----------------------------------------------------------------------------- 1 exp Tooth demineralization/ 7492 2 demineralization.mp. 879 3 caries.mp. 1798 4 caires.mp. 0 5 craies.mp. 0 6 careis.mp. 1 7 carise.mp. 0 8 (teeth adj3 cavit:).mp. 32 9 (tooth adj3 cavit:).mp. 97 10 (dental adj3 cavit:).mp. 85 11 (dentin adj3 cavit:).mp. 19 12 (enamel adj3 cavit:).mp. 10 13 (teeth adj3 decay:).mp. 58 14 (tooth adj3 decay:).mp. 58 15 (dental adj3 decay:).mp. 47 16 (dentin adj3 decay:).mp. 0 17 (enamel adj3 decay:).mp. 1 18 (active adj decay).mp. 5 19 (rampant adj3 decay:).mp. 4 20 (recurrent adj3 decay:).mp. 5 21 (white adj spot:).mp. 231 22 carious.mp. 109 23 cariology.ti,ab. 2 24 (non-cavitated adj3 lesion:).mp. 0 25 (noncavitated adj3 lesion:).mp. 1 26 Tooth remineralization/ 788 27 (dental adj3 fissure:).mp. 14 28 (tooth adj3 fissure:).mp. 8 29 (teeth adj3 fissure:).mp. 1 30 caries-free.mp. 29 31 cariesfree.mp. 0 32 Cariogenic agents/ 3 33 precavit:.mp. 2 34 (filled adj3 teeth).mp. 45 35 (filled adj3 tooth).mp. 9 36 (oral adj fissure:).mp. 17 37 (tooth adj3 remineraliz:).mp. 1 38 (teeth adj3 remineraliz:).mp. 5 39 dft.mp. 542 40 dfs.mp. 980 41 dmf:.mp. 1235 42 cariogeni:.mp. 164 43 or/1-42 12313 44 Dental leakage/ 609 45 (mineral adj loss).mp. 193 46 or/43-45 12479 47 exp Electric conductivity/ 2474 48 Electrodiagnosis/ 952 49 Electronics, medical/ 1322 50 ECM:.mp. 3799 51 resistance:.mp. 130869 52 conductance:.mp. 20430 53 impedance:.mp. 7229 54 diagnos:.mp. 426184 55 detect:.mp. 409558 56 measurement$1.mp. 194102 57 meter:.mp. 6327 58 monitor:.mp. 153447 59 or/51-58 1134407 60 (electric: or electron:).mp. and 59 46652 61 (current or waveform or volt:).mp. and 59 54936 62 or/47-50,60-61 101987 63 46 and 62 284 64 from 63 keep 1-284 284 *************************** <1> UI - 2000171603 AU - Olausson B AU - Sagvik J IN - Dr. B. Olausson, Dept. of Psychiat./Neurochemistry, University of Goteborg, Molndals Hospital, S-43180 Molndal; Sweden. TI - Pain threshold changes following acupuncture, measured with cutaneous argon laser and electrical tooth pulp stimulation, a comparative study. SO - Progress in Neuro-Psychopharmacology & Biological Psychiatry Vol 24(3) (pp 385-395), 2000. AB - 1. The present study compared the argon laser technique for pain threshold measurements with the previously often used threshold measurements with electrical tooth pulp (TP) stimulation. 2. Conditioning stimuli with acupuncture was given since it previously has been shown to induce pain threshold changes. Acupuncture needles were inserted in the hands and arms and electrically stimulated. 3. The experiments were performed in a single blind fashion comparing pain threshold effects after either acupuncture or placebo. Pain threshold measurements with a method of limits were used with both electrical TP and the argon laser method. 4. In comparison to placebo the pain thresholds increased after acupuncture, both on the face and on the hand, with the argon laser method, while the TP thresholds were not influenced. No significant pain threshold change was detected with either the argon laser or the TP method following placebo treatment. 5. The results indicate that the argon laser used for sensory testing with a method of limits is a useful method for pain threshold measurements. The difference in pain threshold effects induced by acupuncture measured with the argon laser and the TP stimulation, are discussed and related to mechanisms that may differ between the two types of pain threshold measurements. [References: 25] <2> UI - 2000156430 AU - Mannaerts GHH AU - Martijn H AU - Crommelin MA AU - Dries W AU - Van Driel OJR AU - Rutten HJT IN - Dr. H.J.T. Rutten, Department of Surgery, Catharina Hospital, Michelangelolaan 2, 5631 EJ Eindhoven; Netherlands. E-Mail: harmr@iaehv.nl. TI - Feasibility and first results of multimodality treatment, combining EBRT, extensive surgery, and IOERT in locally advanced primary rectal cancer. SO - International Journal of Radiation Oncology, Biology, Physics Vol 47(2) (pp 425-433), 2000. AB - Purpose: To assess the outcome of aggressive multimodality treatment with preoperative external beam radiation therapy (EBRT), extended circumferential margin excision (ECME) and intraoperative electron beam radiation therapy (IOERT) in patients with locally advanced primary rectal cancer. Methods and Materials: Thirty-eight patients with primary locally advanced rectal cancer, but without distant metastases, received multimodality treatment. CT-scan showed extension to other structures in 15 patients (39%) and definite infiltration into the surrounding structures in 23 patients (61%). All patients received preoperative EBRT (dose range 25-61 Gy) and 82% received 50.4 Gy. The resection types were: 12 low anterior resections (31%), 14 abdomino-perineal resections (37%), 6 abdomino- transsacral resections (16%), and 6 pelvic exenterations (16%). The IOERT dose ranged from 10 to 17.5 Gy depending on the completeness of the resection. Results: There was no perioperative mortality. The resection margins were microscopically negative in 31 patients (82%), microscopically positive in 4 (10%), and positive with gross residual disease in 3 patients (8%). Pelvic recurrences were observed in 5 patients (13%) including 3 IOERT infield failures. The overall 3-year local control, disease-free survival (DFS), and survival rates were 82%, 65%, and 72%, respectively. Negative resection margins were the most significant prognostic factor with regard to DFS (p = 0.0003) and distant control (p = 0.002) compared with cancer involved surgical margins. Conclusion: A high percentage of curative resections can be achieved in this group of patients with locally advanced rectal cancers. Adding IOERT to preoperative EBRT and ECME achieves high local control rates and possibly improves survival. (C) 2000 Elsevier Science Inc. [References: 53] <3> UI - 2000158792 AU - Beringer K AU - Botzi C AU - Hemmer W AU - Focke M AU - Gotz M AU - Jarisch R IN - Dr. K. Beringer, Floridsdorfer Allergie Zentrum, Franz-Jonas-Platz 8, 1210 Wien; Germany. TI - Pili trianguli et canaliculi: A case report describing the association of uncombable hair with atopic dermatitis and tooth anomalies. [German] SO - Hautarzt Vol 51(4) (pp 266-269), 2000. AB - We report on a child with pili trianguli et canaliculi. This hair shaft abnormality belongs to a heterogeneous group of diseases which are included under the synonym uncombable hair. The diagnosis was confirmed by scanning electron microscopy, revealing hair shafts with a characteristic longitudinal groove. In addition the girl suffered from atopic eczema and tooth anomalies. Our findings suggest that this disorder could represent a tricho-odontal subtype of ectodermal dysplasia. [References: 18] <4> UI - 2000154542 AU - Nunez-Vergara LJ AU - Sturm JC AU - Olea-Azar C AU - Navarrete-Encina P AU - Bollo S AU - Squella JA IN - L.J. Nunez-Vergara, Laboratory of Bioelectrochemistry, Fac. of Chemical/Pharmaceutical Sci., University of Chile, Olivos 1007, Santiago; Chile. E-Mail: lnunez@ll.ciq.uchile.cl. TI - Electrochemical, UV-Visible and EPR studies on nitrofurantoin: Nitro radical anion generation and its interaction with glutathione. SO - Free Radical Research Vol 32(5) (pp 399-409), 2000. AB - This paper deals with the reactivity of the nitro radical anion electrochemically generated from nitrofurantoin with glutathione. Cyclic voltammetry (CV) and controlled potential electrolysis were used to generate the nitro radical anion in situ and in bulk solution, respectively and cyclic voltammetry, UV-Visible and EPR spectroscopy were used to characterize the electrochemically formed radical and to study its interaction with GSH. By cyclic voltammetry on a hanging mercury drop electrode, the formation of the nitro radical anion was possible in mixed media (0.015 M aqueous citrate/DMF, 40/60, pH 9) and in aprotic media. A second order decay of the radicals was determined, with a k2 value of 201 and 111 M-1 s-1, respectively. Controlled potential electrolysis generated the radical and its detection by cyclic voltammetry, UV-Visible and EPR spectroscopy was possible. When glutathione (GSH) was added to the solution, an unambiguous decay in the signals corresponding to a nitro radical anion were observed and using a spin trapping technique, a thiyl radical was detected. Electrochemical and spectroscopic data indicated that it is possible to generate the nitro radical anion from nitrofurantoin in solution and that GSH scavenged this reactive species, in contrast with other authors, which previously reported no interaction between them. [References: 24] <5> UI - 2000142001 AU - Jackson JSH AU - Olivotto IA AU - Wai E AU - Grau C AU - Mates D AU - Ragaz J IN - Dr. J.S.H. Jackson, British Columbia Cancer Agency, FVCC, 13750, 96th Avenue, Surrey, BC V3V 1Z2; Canada. TI - A decision analysis of the effect of avoiding axillary lymph node dissection in low risk women with invasive breast carcinoma. SO - Cancer Vol 88(8) (pp 1852-1862), 2000. AB - BACKGROUND. Evidence that avoiding axillary lymph node dissection (AxD) strikes an appropriate balance between morbidity and recurrence risk in patients with invasive breast carcinoma generally is anecdotal and without a formally quantified basis. The current study presents a decision analysis of the difference in 5-year disease free survival (DFS) rate between treatment scenarios with and without routine AxD. METHODS. To derive quantitative estimates of the effect of avoiding AxD on 5-year DFS, the authors examined outcomes for women undergoing 2 treatment scenarios: AxD or no AxD with adjuvant therapy decisions based on risk factors in the primary tumor. Eligible patients belonged to 2 lymph node metastases risk groups: low (patients without palpable lymph nodes and lymphatic or vascular invasion [LVI] negative tumors <=0.5 cm in greatest dimension) and moderate (patients with mammographically detected, LVI negative tumors, between 0.6-2.0 cm in greatest dimension or patients with palpable LVI negative tumors between 0.6- 1.0 cm in greatest dimension with nonpalpable lymph nodes). Along with observed data regarding treatment and recurrence, the authors employed estimates of the efficacy of chemotherapy, tamoxifen, and regional radiation therapy derived from published randomized trials to estimate the 5-year DFS rate for treatment scenarios with and without AxD. RESULTS. Patients in the low risk group had a 5% risk of lymph node metastases. In these women, eliminating AxD and treating no patients with chemotherapy and/or tamoxifen resulted in a < 1% decrease in the 5-year DFS rate. Patients in the moderate risk group had a 10% risk of lymph node metastases. Eliminating AxD and treating only those women with Grade 3 tumors > 1 cm in greatest dimension with chemotherapy and/or tamoxifen resulted in a 1.8% decrease in the 5-year DFS rate. However, if all patients in this group were treated with chemotherapy and/or tamoxifen and no AxD, the 5-year DFS rate increased by 2.7%. CONCLUSIONS. In patients with a low risk of lymph node metastases, it was estimated that eliminating AxD may result in only minimal changes in the estimated 5-year DFS rate. (C) 2000 American Cancer Society. [References: 45] <6> UI - 2000136992 AU - Wolff AC AU - Davidson NE IN - Dr. A.C. Wolff, Johns Hopkins Oncology Center, Cancer Research Building, 1650 Orleans St, Baltimore, MD 21231-1000; United States. E-Mail: awolff@jhmi.edu. TI - Primary systemic therapy in operable breast cancer. SO - Journal of Clinical Oncology Vol 18(7) (pp 1558-1569), 2000. AB - Purpose: Laboratory studies suggest that primary systemic therapy (PST) could improve control of micro-metastatic disease and impact on overall survival (OS). This article examines the rationale for and preclinical and clinical data of PST in operable breast cancer and the potential role of intermediate biomarkers as predictive and/or prognostic factors for response and survival. Design and Method: We conducted an extensive literative review (including MEDLINE) on proclinlcal studies, single-arm feasibility studies, large randomized single- and multi-institutional trials, and laboratory correlate studies of PST in breast cancer. Results: Small trials in locally advanced disease showed high initial rates of response and local control. Six randomized clinical trials (RCTs) of PST for palpable, operable breast cancer have been reported since 1991 (from 204 to 1,523 patients each). These data clearly show a small but significant (less than 10%) absolute increase in the use of breast-conservation treatment (BCT) with similar rates of local control. Although one study showed better disease-free survival (DFS) and another showed better OS, most studies did not show any survival advantage of primary versus adjuvant systemic therapy. Thus far, pathologic complete response seems to be the best predictor of survival, but clinical response assessment correlates poorly with pathologic response. Pilot studies demonstrated feasibility of procuring tissue at diagnosis and after treatment for assays of potential intermediate biomakers. Initial data suggest a potential correlation between markers of proliferation and apoptosis and in vivo chemotherapy sensitivity. Conclusion: Thus far, RCTs of PST versus standard adjuvant therapy have not shown any clear benefit for DFS or OS in early breast cancer. Ongoing trials should determine if specific subsets of patients at risk would benefit from additional systemic therapy and the potential role of intermediate biomarkers in identifying such women. Although PST results in a small increase in the rate of BCT with similar rates of local control, current PST strategies should not replace standard adjuvant approaches. Rather, they represent an acceptable alternative to women with palpable, operable tumors and an excellent arena for clinical trials. (C) 2000 by American Society of Clinical Oncology. [References: 69] <7> UI - 2000129666 AU - Cao J AU - Fyfe MCT AU - Stoddart JF AU - Cousins GRL AU - Glink PT IN - J.F. Stoddart, Dept. of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095; United States. E-Mail: stoddart@chem.ucla.edu. TI - Molecular shuttles by the protecting group approach. SO - Journal of Organic Chemistry Vol 65(7) (pp 1937-1946), 2000. AB - Two new [2]rotaxane-based molecular shuttles, in which a mechanically bound dibenzo[24]crown-8 (DB24C8) macroring shunts back and forth between two dialkylammonium recognition sites situated on a chemical dumbbell, have been constructed by a novel synthetic strategy that relies upon the use of the tert-butoxycarbonyl (Boc) protecting group. During the syntheses of both molecular shuttles, this protecting group masks a dialkylammonium recognition center which is liberated only after the [2]rotaxane constitution is established. In both cases, the molecular shuttles' other dialkylammonium center is essential for the rotaxane-forming reactions and it ensures that DB24C8 is interpenetrated by threadlike precursors, as a result of noncovalent bonding interactions, to produce [2]pseudorotaxanes which are stoppered subsequently through 1,3-dipolar cycloadditions between azides and bulky acetylenedicarboxylates. The new molecular shuttles have been examined by means of dynamic 1H NMR spectroscopy, which reveals that the movements of the DB24C8 macroring are very highly dependent both on solvent properties and on the nature of the spacer unit linking the two dialkylammonium centers. Thus, DB24C8 shunts facilely between the dialkylammonium centers when the shuttles are dissolved in solvents that readily donate their nonbonding electrons into noncovalent bonds, e.g., DMF, and when spacer units that do not offer much steric resistance to shuttling, e.g., hexamethylene, are used. On the other hand, shuttling is difficult in solvents that are less inclined to donate their electrons into noncovalent bonds, e.g., (CDCl2)2, and when relatively bulky benzenoid spacer units, e.g., p-xylylene, link the two dialkylammonium centers. It has been proposed that the DB24C8 might act as a 'ferry' which carries a proton between dialkylammonium and dialkylamine moieties in a singly protonated [2]rotaxane by means of ion-dipole interactions. <8> UI - 2000125424 AU - Whitters CJ AU - Strang R IN - Dr. C.J. Whitters, Department of Clinical Physics, Glasgow Dental Hospital and School, 378 Sauchiehall Street, Glasgow G2 3 JZ; United Kingdom. E-Mail: j.whitters@dental.gla.ac.uk. TI - Preliminary investigation of a novel carbon dioxide laser for applications in dentistry. SO - Lasers in Surgery & Medicine Vol 26(3) (pp 262-269), 2000. AB - Background and Objective: A novel pulsed CO2 laser was examined for its ability to ablate hard dental tissues. Study Design/Materials and Methods: Lased human enamel surfaces were viewed using light and scanning electron microscopy for evidence of adverse structural changes. In vitro shear bond strength tests were conducted on composite resin bonded to lased enamel surfaces and compared with conventionally prepared specimens. A thermal camera was used to monitor temperature changes during cavity preparation in tooth slabs to assess likely changes to the dental pulp. Results: No charring or surface cracks were observed on lased enamel surfaces using both microscopic techniques. Bonding of the lased enamel surfaces to composite resin was not significantly different from the acid-etched control group. For cavities with a remaining dentine thickness of less than 1 mm, the temperature rise was less than 6 [degree] C. Conclusion: A novel pulsed CO2 laser shows promise for cutting cavities in teeth. (C) 2000 Wiley-Liss, Inc. [References: 21] <9> UI - 2000122244 AU - Oeffinger KC AU - Eshelman DA AU - Tomlinson GE AU - Buchanan GR AU - Foster BM IN - Dr. K.C. Oeffinger, Dept. of Family Pract./Commun. Med., Texas Univ. Southwestern Med. Center, 5323 Harry Hines Blvd., Dallas, TX 75235-9067; United States. TI - Grading of late effects in young adult survivors of childhood cancer followed in an ambulatory adult setting. SO - Cancer Vol 88(7) (pp 1687-1695), 2000. AB - BACKGROUND. The objective of the current study was to describe a multidisciplinary transition program for following young adult survivors of childhood cancer in an adult-based ambulatory medical setting and to report the late effects with grades of toxicity diagnosed in all adult survivors followed in the program. METHODS. The study population was comprised of all young adult survivors (n = 96) of childhood cancer who were seen in the After the Cancer Experience (ACE) Young Adult Program prior to January 31, 1999. The median age of the survivors was 22.8 years (range, 17-34 years) and the median interval from the time of cancer diagnosis was 15.2 years (range, 6-25 years). Primary cancer groups included: leukemia, 33%; sarcoma, 24%; Hodgkin disease, 15%; non-Hodgkin lymphoma, 12%; Wilms' tumor, 9%; and other, 7%. Late effects were graded using the Common Toxicity Criteria, Version 2 (CTCv2), developed by the National Cancer Institute. RESULTS. Approximately 69% of the patients (66 of 96) had at least 1 late effect. Thirty-three percent of patients had a single late effect whereas 36% had >= 2 late effects. Thirty percent of patients had a CTCv2 Grade 3 or 4 late effect. CONCLUSIONS. The current study represents an example of a successful multidisciplinary transition program in an ambulatory, adult setting for young adult survivors of childhood cancer. Late effects of cancer treatment are common in young adult survivors, with approximately 33% being moderate to severe. Further studies are needed to modify CTCv2-with the aim of developing a reliable and valid tool to assess late effects in long term survivors of childhood cancer. (C) 2000 American Cancer Society. [References: 25] <10> UI - 2000107652 AU - Domon T AU - Osanai M AU - Yawaka Y AU - Suzuki R AU - Takahashi S AU - Yamamoto T AU - Wakita M IN - T. Domon, Dept. of Oral Anatomy II, Anatomy II, Hokkaido Univ. Sch. Dentistry, Kita 13, Nishi 7, Kita-Ku, Sapporo 060-0813; Japan. TI - Ultrastructural study of the root dentine surface resuming resorption on human deciduous teeth. SO - Annals of Anatomy Vol 182(2) (pp 175-184), 2000. AB - Resorption of deciduous teeth is not continuous, but alternates with periods of repair or rest. Dentine surfaces in periods of rest or repair resume resorption by odontoclasts during physiological root resorption of the deciduous teeth. However, no observations of such dentine surfaces have been shown. The characteristic feature of the dentine surfaces resuming resorption remains unknown. Tartrate-resistant acid phosphatase activity (TRAP) was detected on human deciduous teeth. The root resorbing surfaces on these teeth were photographed with a whole-mount light microscope, and the photographed areas were serially sectioned into 0.5 mum semithin sections. Preodontoclasts and odontoclasts were three-dimensionally reconstructed. On root resorbing surfaces, areas with small scattered TRAP-positive cells were observed among areas with many TRAP-positive resorbing odontoclasts and TRAP-negative areas. The sections showed that areas with small scattered TRAP-positive cells have features similar to those of TRAP-negative areas, but there were three kinds of characteristic TRAP-positive cells: preodontoclasts, odontoclasts forming small lacunae, and preodontoclasts and odontoclasts with cytoplasmic processes extending to the dentine surface, which is covered with cells. These results suggest that the areas with small scattered TRAP-positive cells could be at the stage of resuming resorption, and show that the presence of preodontoclasts and odontoclasts with cytoplasmic processes extending to the covered dentine surface is a characteristic feature of the dentine surface at this stage. [References: 30] <11> UI - 2000096010 AU - Kafferlein HU AU - Goen T AU - Muller J AU - Wrbitzky R AU - Angerer J IN - J. Angerer, Inst./Poliklin. fur Arbeits-, Sozial, Friedrich-Alexander Univ. Erlangen, Schillerstrasse 25/29, 91054 Erlangen; Germany. E-Mail: angerer@asumed.med.uni-erlangen.de. TI - Biological monitoring of workers exposed to N,N-dimethylformamide in the synthetic fibre industry. SO - International Archives of Occupational & Environmental Health Vol 73(2) (pp 113-120), 2000. AB - Objectives: Monitoring of workplace air and biological monitoring of 23 workers exposed to N,N-dimethylformamide (DMF) in the polyacrylic fibre industry was carried out on 4 consecutive days. The main focus of the investigation was to study the relationship between external and internal exposure, the suitability of the metabolites of DMF for biological monitoring and their toxicokinetic behaviour in humans. Methods: Air samples were collected using personal air samplers. The limit of detection (LOD) for DMF using an analytical method recommended by the Deutsche Forschungsgemeinschaft (DFG) was 0.1 ppm. The urinary metabolites, N-hydroxymethyl-N-methylformamide (HMMF), N-methylformamide (NMF), and N-acetyl-S-(N-methylcarbamoyl)-cysteine (AMCC), were determined in one analytical run by gas chromatography with thermionic sensitive detection (GC/TSD). The total sum of HMMF and NMF was determined in the form of NMF. The LOD was 1.0 mg/l for NMF and 0.5 mg/l for AMCC. Results and conclusions: The external exposure to DMF vapour varied greatly depending on the workplace (median 1.74 ppm, range < 0.1-159.77 ppm). Urinary NMF concentrations were highest in post-shift samples. They also covered a wide range (< 1.0-108.7 mg/l). This variation was probably the result of different concentrations of DMF in the air at different workplaces, dermal absorption and differences in the protective measures implemented by each individual (gloves, gas masks etc.). The urinary NMF concentrations had decreased almost to zero by the beginning of the next shift. The median half-time for NMF was determined to be 5.1 h. The concentrations of AMCC in urine were determined to be in the range from < 0.5 to 204.9 mg/l. Unlike the concentrations of NMF, the AMCC concentrations did not decrease during the intervals between the shifts. For the exposure situation investigated in our study, a steady state was found between the external exposure to DMF and the levels of AMCC excreted in urine about 2 days after the beginning of exposure. AMCC is therefore excreted more slowly than NMF. The half-time for AMCC is more than 16 h. Linear regression analysis for external exposure and urinary excretion of metabolites was carried out for a sub-group of 12 workers. External exposure to 10 ppm DMF in air (the current German MAK value) corresponds to an average NMF concentration of about 27.9 mg/l in post-shift urine from the same day and an average AMCC concentration of 69.2 mg/l in pre-shift urine from the following day. NMF in urine samples therefore represents an index of daily exposure to DMF, while AMCC represents an index of the average exposure over the preceding working days. AMCC is considered to be better suited for biomonitoring purposes because (1) it has a longer half-time than NMF and (2) its formation in humans is more closely related to DMF toxicity. [References: 38] <12> UI - 2000081541 AU - Sivakolundu SG AU - Mabrouk PA IN - P.A. Mabrouk, Department of Chemistry, Northeastern University, Boston, MA 02115; United States. TI - Cytochrome c structure and redox function in mixed solvents are determined by the dielectric constant. SO - Journal of the American Chemical Society Vol 122(7) (pp 1513-1521), 2000. AB - Cyclic voltammetry (CV), UV-visible (UV-vis); circular dichroism (CD), and resonance Raman (lambda(ex) = 406.7, 413.1 nm) spectroscopy have been used to probe the structure and redox function of horse cytochrome c (cyt c) in aqueous mixtures of three water-miscible organic solvents, specifically, acetonitrile (ACN), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) containing 100-60% water. As the concentration of the organic solvent is increased, significant changes are observed in the spectroscopy of ferricytochrome c (ferricyt c) with the greatest structural changes observed for ferricyt c in mixed solvent media with the lowest dielectric constant (30% ACN in this work). In the UV-visible spectrum, the Soret band blue shifts (1 nm) and the intensity of the 695 nm band decreases. UV CD (185-240 nm) suggest that changes in the protein secondary structure on going from aqueous to nonaqueous media are relatively small and that the protein structure remains largely intact in nonaqueous media. In the visible CD spectrum, the negative 417 nm CD signal disappears, signaling significant changes in heme-polypeptide interactions. Shifts in the vibrational frequencies and changes in the relative intensities of bands in both the marker band and low frequency spectral regions of cyt c in mixed media have been attributed to mixtures of the type IVa, IVb, Va, and Vb alkaline conformers of ferricyt c in mixed media. The change in the composition of these mixtures as the dielectric constant decreases parallels closely that reported by Dopner et al. for yeast iso-1-cytochrome c in aqueous solution as the aqueous solution pH is raised from pH 7 to pH 10. The spectroscopic characteristics of the reduced form of cyt c in mixed solvents are very similar to those of native ferrous cyt c (ferrocyt c) in aqueous solution, reflecting minimal change in heme active site structure in the reduced state. Cyt c in mixed solvents exhibits a quasireversible, one-electron response at 4,4'-dipyridyl disulfide-modified Au electrodes between 5 and 200 mV/s. The redox potential for cyt c in mixed media (199-274 mV vs SHE) and the rate of heterogeneous electron transfer (0.4-3.5 x 10-3 cm/s) decrease as the organic solvent content of the solvent medium increases. Our data support the conclusion that the internal dielectric constant within the heme crevice plays the key role in determining the reduction potential of cyt c and suggest that the effects of axial ligation (Met vs Lys) may be less significant than previously believed. <13> UI - 2000055481 AU - Gold MR AU - Olsovsky MR AU - DeGroot PJ AU - Cuello C AU - Shorofsky SR IN - Dr. M.R. Gold, Division of Cardiology, Univ. of Maryland Medical System, 22 S. Greene Street, Baltimore, MD 21201; United States. E-Mail: MGold@medicine.ab.umd.edu. TI - Optimization of transvenous coil position for active can defibrillation thresholds. SO - Journal of Cardiovascular Electrophysiology Vol 11(1) (pp 25-29), 2000. AB - Effect of SVC Position on DFT. Introduction: Lead systems that include an active pectoral pulse generator are now standard for initial defibrillator implantations. However, the optimal transvenous lead system and coil location for such active can configurations are unknown. The purpose of this study was to evaluate the benefit and optimal position of a superior vena cava (SVC) coil on defibrillation thresholds with an active left pectoral pulse generator and right ventricular coil. Methods and Results: This prospective, randomized study was performed on 27 patients. Each subject was evaluated with three lead configurations, with the order of testing randomized. Biphasic shocks were delivered between the right ventricular coil and an active can alone (unipolar), or an active can in common with the proximal coil positioned either at the right atrial/SVC junction (low SVC) or in the left subclavian vein (high SVC). Stored energies at defibrillation threshold were higher for the single-coil, unipolar configuration (11.2 +/- 6.6 J) than for the high (8.9 +/- 4.2 J) or low (8.5 +/- 4.2 J) SVC configurations (P < 0.01). Moreover, 96% of subjects had low (<= 15 J) thresholds with the SVC coil in either position compared with 81% for the single-coil configuration. Shock impedance (P < 0.001) was increased with the unipolar configuration, whereas peak current was reduced (P < 0.001). Conclusion: The addition of a proximal transvenous coil to an active can unipolar lead configuration reduces defibrillation energy requirements. The position of this coil has no significant effect on defibrillation thresholds. [References: 29] <14> UI - 2000049573 AU - Carretta N AU - Tricoli V AU - Picchioni F IN - V. Tricoli, Dipartimento Ingegneria Chimica, Chimica Industriale/Sci. Materiali, University of Pisa, 56126 Pisa; Italy. E-Mail: v.tricoli@ing.unipi.it. TI - Ionomeric membranes based on partially sulfonated poly(styrene): Synthesis, proton conduction and methanol permeation. SO - Journal of Membrane Science Vol 166(2) (pp 189-197), 2000. AB - Homogeneuosly sulfonated poly(styrene) (SPS) was prepared with various concentration of sulfonic acid groups in the base polymer. Membranes cast from these materials were investigated in relation to proton conductivity and methanol permeability in the temperature range from 20 [degree] C to 60 [degree] C. It was found that both these properties increase as the polymer is increasingly sulfonated, with abrupt jumps occurring at a concentration of sulfonic acid groups of about 15mol%. The most extensively sulfonated membrane exhibited conductivity equal to that of Nafion. As a consequence, this membrane material is potentially an appealing alternative to the very expensive Nafion, for a number of electrochemical applications. For the membrane with the highest degree of sulfonation we measured a methanol permeability about 70% smaller than for Nafion. This characteristic is especially desirable in applications related to the direct methanol fuel cell (DMFC). Copyright (C) 2000 Elsevier Science B.V. [References: 28] <15> UI - 2000040977 AU - Faderl S AU - Kantarjian HM AU - Thomas DA AU - Cortes J AU - Giles F AU - Pierce S AU - Albitar M AU - Estrov Z IN - Dr. H.M. Kantarjian, Department of Leukemia, Box 61, MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030; United States. TI - Outcome of philadelphia chromosome-positive adult acute lymphoblastic leukemia. SO - Leukemia & Lymphoma Vol 36(3-4) (pp 263-273), 2000. AB - Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL) represents the most common cytogenetic abnormality in adult ALL. It is found in 15% to 30% of patients, and its incidence increases with age. As in children, prognosis in Ph-positive adult ALL is poor. No therapeutic approach has had substantial impact on its unfavorable course. We analyzed the characteristics and outcome of newly diagnosed adults with Ph-positive ALL treated at the M.D. Anderson Cancer Center between 1980 and 1997. The diagnosis of patients was based on typical morphological and immunophenotypic criteria of marrow aspirate and biopsy specimens. Cytogenetic and molecular studies were also performed. A total of 67 patients were included in this study. From 1980 until 1991, 38 patients with Ph-positive ALL were treated with vincristine, Adriamycin, and dexamethasone (VAD), or with acute myeloid leukemia (AML)-like induction protocols. Since 1992 a total of 29 patients received induction therapy with an intensified treatment protocol, called 'hyper-CVAD' The outcome of patients treated with standard and intensified treatment regimens was compared and results of our institution contrasted with data obtained from other centers. Ph-positive ALL was present in 67 of 498 patients with newly diagnosed ALL (13%). Patients with Ph-positive. ALL had a higher median age (44 versus 34, P = 0.007), higher median white blood cell (WBC) counts at presentation (25 versus 8: P = 0.0002), and higher peripheral median percentage of blast counts (63 versus 40, P = 0.023). FAB subtype L2 (70% versus 49%, P = 0.001) and CALLA-positive pre-B immunophenotype (75% versus 37%, P < 0.001) predominated among Ph-positive ALL. Myeloid marker coexpression was more frequent in Ph-positive ALL when compared with Ph-negative ALL (52% vs. 27% for CD13, P < 0.001, and 44% vs, 27% for CD33, P = 0.005). Among patients treated with hyper-CVAD, the complete remission (CR) rate was 90% versus 55% (P = 0.002) with pre-hyper-CVAD regimens (VAD and AML-like induction protocols), the median CR duration was 43 weeks versus 32 weeks (P > 0.5), median disease-free survival (DFS) was 42 weeks versus 29 weeks (P = 0.008) and median survival was 66 weeks versus 45 weeks (P > 0.5). Patients with hyper diploid Ph-positive ALL on hyper-CVAD therapy achieved significantly longer CR duration and DFS than hypo- and pseudodiploid cases (59 weeks versus 42 and 31 weeks, P = 0.02 and 0.04, respectively). In contrast, patients treated with regimens prior to hyper-CVAD had significantly shorter CR duration (21 weeks versus 33 and 29 weeks, P = 0.03) and DFS with hyperdiploid karyotypes when compared to pseudodiploid and hypodiploid cases (16 weeks versus 30 and 13 weeks, P = 0.008). In conclusion, our results demonstrate improved response rate and DFS with current intensive regimens (hyper-CVAD) in patients with Ph-positive ALL, but no advantage in overall survival. [References: 29] <16> UI - 2000033779 AU - Wang R AU - Lu X AU - Xin H AU - Wu M IN - M. Wu, Changchun Inst. of Applied Chemistry, Chinese Academy of Sciences, National Analytical Research C.E.S., Changchun, Jilin 130022; China. TI - Separation of phenothiazines in aqueous and non-aqueous capillary electrophoresis. SO - Chromatographia Vol 51(1-2) (pp 29-36), 2000. AB - Four phenothiazines, promethazine, dioxypromethazine, chlorpromazine, and trifluoperazine have been separated by capillary electrophoresis using N, N, -dimethylformamide (DMF) as separation medium with UV absorbance detection. High voltage and concentrated buffer were used with small current and low electroosmosis. Good resolution and high column efficiency were obtained. Separation selectivity in DMF was different from that in water because of the different solvation interactions. The influence of buffer composition on separation selectivities and electroosmosis were also studied. [References: 18] <17> UI - 2000019843 AU - Hilton MF AU - Bates RA AU - Godfrey KR AU - Chappell MJ AU - Cayton RM IN - Dr. M.J. Chappell, School of Engineering, University of Warwick, Coventry; United Kingdom. E-Mail: mjc@eng.warwick.ac.uk. TI - Evaluation of frequency and time-frequency spectral analysis of heart rate variability as a diagnostic marker of the sleep apnoea syndrome. SO - Medical & Biological Engineering & Computing Vol 37(6) (pp 760-769), 1999. AB - The sleep apnoea/hypopnoea syndrome (SAHS) elicits a unique heart rate rhythm that may provide the basis for an effective screening tool. The study uses the receiver operator characteristic (ROC) to assess the diagnostic potential of spectral analysis of heart rate variability (HRV) using two methods, the discrete Fourier transform (DFT) and the discrete harmonic wavelet transform (DHWT). These two methods are compared over different sleep stages and spectral frequency bands. The HRV results are subsequently compared with those of the current screening method of oximetry. For both the DFT and the DHWT, the most diagnostically accurate frequency range for HRV spectral power calculations is found to be 0.019-0.036 Hz (denoted by AB2). Using AB2, 15 min sections of non-REM sleep data in 40 subjects produce ROC areas, for the DFT, DHWT and oximetry, of 0.94, 0.97 and 0.67, respectively. In REM sleep, ROC areas are 0.78, 0.79 and 0.71, respectively. In non-REM sleep, spectral analysis of HRV appears to be a significantly better indicator of the SAHS than the current screening method of oximetry, and, in REM sleep, it is comparable with oximetry. The advantage of the DHWT over the DFT is that it produces a greater time resolution and is computationally more efficient. The DHWT does not require the precondition of stationarity or interpolation of raw HRV data. [References: 40] <18> UI - 2000004968 AU - Maurice C AU - Schollhorn B AU - Aboab B AU - Mousset G AU - Mousty C IN - C. Maurice, Equipe d'Electrosynthese, Electroanalyse Bioorganique, Universite Blaise Pascal, 24 Avenue des Landais 63177, 63177 Aubiere Cedex; France. TI - Electrochemical behaviour of new electroreducible amphiphilic saccharide derivatives II: Electroreduction in protic media. SO - NEW J CHEM, Vol 23(12) (pp 1171-1175), 1999. AB - The electrochemical reduction of new amphiphilic molecules derived from sugars and aromatic ketones has been performed in protic media under basic and acidic conditions. Exhaustive electrolyses have yielded, regardless of pH, the alcohol resulting from two-electron and two-proton exchanges. No trace of pinacol was detected. This unusual behaviour has been related to the properties of the saccharidic moiety, which can favour a highly hindered bent back conformation. The dimerisation reaction is thus less probable. Molecular calculations and a dynamic study in aqueous solution have shown that the less energetic conformations are stabilised by hydrogen bonds between the sugar moiety and the carbonyl group by means of six water molecules, three of them building a solvation chain between the carbonyl function and the primary alcohol of the sugar. As a comparison the same calculations, applied to an aprotic solvent (DMF), indicate an extended form for the conformation of lowest energy. [References: 15] <19> UI - 1999422835 AU - Solomon SD AU - Smith JH AU - O'Brien J IN - Dr. J. O'Brien, UCSF Medical Center, Box 0730, 10 Kirkham Street, San Francisco, CA 94143; United States. TI - Ocular manifestations of systemic malignancies. SO - Current Opinion in Ophthalmology Vol 10(6) (pp 447-451), 1999. AB - Ocular manifestations of systemic malignancy are important for both the ophthalmologist and the internist to recognize because they may precede the diagnosis of cancer. This review of the current literature discusses the clinical manifestations etiology, and potential therapeutic interventions for a group of visual paraneoplastic syndromes, including carcinoma-associated retinopathy and melanoma-associated retinopathy. These conditions are characterized by elevated serum levels of autoantibodies directed against tumor antigen that cross-react with retinal proteins, resulting in rod and cone dysfunction. The clinical presentation, site of origin, frequency, and intraocular distribution of tumors metastatic to the eye are also reviewed. [References: 24] <20> UI - 1999389364 AU - Chiu B IN - Dr. B. Chiu, Dept. of Lab. Medicine-Pathology, St. Michael's Hospital, 30 Bond St, Toronto, Ont. M5B 1W8; Canada. TI - Multiple infections in carotid atherosclerotic plaques. SO - American Heart Journal Vol 138(5 II) (pp S534-S536), 1999. AB - Background: Chlamydia pneumoniae, cytomegalovirus, herpes simplex virus, and recently, periodontal disease, have been associated with human atherosclerosis. Porphyromonas gingivalis and Streptococcus sanguis are major pathogens associated with periodontitis, a common chronic inflammatory condition in adults. Investigators have found that these infectious agents may influence vascular cell functions by inducing thrombus formation, vascular cell proliferation, apoptosis, and cell death. Methods and Results: The main purpose of our study was to investigate the relation between the presence of multiple infectious agents in human carotid endarterectomy specimens and pathoanatomic features of the corresponding carotid plaques. Histologically, plaque rupture of the fibrous cap and communication of the luminal thrombus with the central necrotic lipid core was seen in or at proximity to the macrophage-rich shoulder (unstable plaque region). Thrombus within the lipid core without plaque rupture was occasionally found near the internal elastic lamina, associated with increased vascularity and lymphocytic infiltrate. Apoptosis, as detected by both the immunohistochemical staining of apoptosis-related proteins and in situ labeling of internucleosomally degraded DNA, was common in atherosclerotic plaques. Immunostainings for C pneumoniae, cytomegalovirus, herpes simplex virus-1, P gingivalis, and S sanguis were positive in the carotid plaques. From 1 to 4 organisms were found in the same specimen. The micro-organisms were immunolocalized in plaque shoulders and lymphohistiocytic infiltrate, associated with ulcer and thrombus formation, and adjacent to areas of strong labeling for apoptotic bodies. Conclusions: Our data provide evidence that multiple infectious agents may be found in atherosclerotic plaques, and sometimes in the same specimen. The current study is the first to report the detection of 2 major odontopathogens, P gingivalis and S sanguis, in atherosclerotic plaques. The immunolocalization of these micro-organisms within unstable plaque regions and their association with plaque ulceration, thrombosis, and apoptosis in vascular cells are intriguing. Multiple infectious agents may alter vascular cell function and provide a 'trigger' for acute ischemic stroke events. Further evidence from human studies and animal models will be needed. [References: 26] <21> UI - 1999388394 AU - Hossain M AU - Nakamura Y AU - Kimura Y AU - Ito M AU - Yamada Y AU - Matsumoto K IN - Dr. K. Matsumoto, Department of Endodontics, Showa University School of Dentistry, 2-1-1 Kitasenzoku, Ohta-ku, Tokyo 145-8515; Japan. E-Mail: koukichi@senzoku.showa-u.ac.jp. TI - Acquired acid resistance of dental hard tissues by CO2 laser irradiation. SO - Journal of Clinical Laser Medicine & Surgery Vol 17(5) (pp 223-226), 1999. AB - Objective: This investigation was performed to evaluate the effect of CO2 laser irradiation on the acquired acid resistance of dental hard tissues to artificial caries-like formation and the ultrastructure of lased areas was morphologically investigated in vitro. Summary Background Data: In recent years, many studies have been carried out to evaluate the effect of the CO2 laser on the enhanced resistance to artificial caries formation of enamel. However, a limited number of papers concerning its effect on dentin have been published. Methods: A CO2 laser of 10.6 mum wavelength was used to irradiate human enamel and dentin samples from 20 extracted human molar teeth, and samples were subjected to 2 mul of 0.1 M lactic acid solution (pH 4.8) for 24 h at 36 [degree] C. The parts per million (ppm) of calcium ion (Ca2+) dissolved in each solution was determined by atomic absorption spectrophotometry and the morphological changes were investigated by scanning electron microscopy (SEM). Results: The lowest mean Ca2+ ppm was recorded in the samples irradiated at 3 W, followed by 2 W, 1 W, and unlased samples. SEM observation showed that the lased areas were melting with solidification of the smear layer. Even after acid demineralization, the lased surfaces were almost unchanged. Conclusions: The results of this study suggested that CO2 laser irradiation could sufficiently melt and solidify the enamel and dentin surfaces and thus enhance resistance to artificial caries-like formation. [References: 23] <22> UI - 1999388391 AU - Yonaga K AU - Kimura Y AU - Matsumoto K IN - Dr. K. Yonaga, Department of Endodontics, Showa University School of Dentistry, 2-1-1 Kitasenzoku, Ohta-ku, Tokyo 145-8515; Japan. E-Mail: yonaga@senzoku.showa-u.ac.jp. TI - Treatment of cervical dentin hypersensitivity by various methods using pulsed Nd:YAG laser. SO - Journal of Clinical Laser Medicine & Surgery Vol 17(5) (pp 205-210), 1999. AB - Objective: The purpose of this study was to evaluate the results of two irradiated regions, the cervical and apical, for cervical dentin hypersensitivity treatment using pulsed a Nd:YAG laser with or without black ink. Summary Background Data: There has been no reports on the irradiated area(s) except the cervical region for dentin hypersensitivity treatment using pulsed Nd:YAG laser. Methods: A total of 180 teeth diagnosed with cervical dentin hypersensitivity in 54 (39 females, 15 males, aged 21 to 73) healthy adult patients were included in this study, and teeth were randomly divided into four groups of 45 each. Sensitivity was rated using a blast from a fully depressed air syringe on a four-grade scale both before and up to 2 months after laser treatment. The effectiveness was evaluated on the change in the degree of hypersensitivity after laser treatment. The tooth surfaces in groups 1 and 2 were observed by the replica model method using scanning electron microscopy (SEM). Results: The methods of irradiation at the cervical regions were better than those at the apical regions except for the period 2 months later. The laser effect was enhanced by black ink at both areas. The effective (excellent and good) rate was decreased depending on the time in every group. SEM observation at the tooth surfaces from group 2 showed that dentinal tubules were occluded or narrowed after laser irradiation. Conclusions: These results show that the method of irradiation by a pulsed Nd:YAG laser at cervical regions with black ink is the most effective for cervical dentin treatment of hypersensitivity and recurrence by this method is less than in other methods. [References: 47] <23> UI - 1999386332 AU - Carrie C AU - Mascard E AU - Gomez F AU - Habrand J-L AU - Alapetite C AU - Oberlin O AU - Moncho V AU - Hoffstetter S IN - Dr. C. Carrie, Radiation Therapy Department, Centre Leon Berard, 28 rue Laennec, 69373 Lyon Cedex 08; France. E-Mail: carrie@lyon.fnclcc.fr. TI - Nonmetastatic pelvic Ewing sarcoma: Report of the French Society of Pediatric Oncology. SO - Medical & Pediatric Oncology Vol 33(5) (pp 444-449), 1999. AB - Background. Since January, 1984, 59 children with histologically confirmed Ewing sarcoma of the pelvic bone have been treated with three successive chemotherapy protocols recommended by the French Society of Pediatric Oncology. The purpose of the current study was to evaluate the role of surgery and/or radiotherapy in local progression-free, disease-free, and overall survivals (LPFS, DFS, and OS, respectively). Procedure. We retrospectively examined 59 children treated for nonmetastatic, pelvic Ewing sarcoma over the last 12 years. All were first treated with chemotherapy according to the current French protocol. Six patients developed progressive disease before local treatment and were excluded for local control and survival analysis. Local treatment was surgery alone in 17 cases, radiation therapy in 27 cases, and surgery plus radiation therapy in 9 cases. Results. With a median of follow-up of 6.5 years, no significant differences in local control or survival were observed with the three chemotherapeutic protocols. Of the 53 patients evaluable for local control, 6 relapsed locally only, 8 had local and distant relapses, and 9 had distant metastases only. The 5-year OS rate was worst for patients with radiotherapy alone compared to those with surgery or combined modality treatment (44 % vs. 72 %, P = 0.043). The 5-year LPFS and DFS rates were worst in the radiotherapy-alone group but not significantly (63% vs. 79%, P = 0.22 and 42% vs 71%, P =0.07, respectively). The importance of surgery to OS and DFS was confirmed by multivariate analysis (P = 0.026 and P = 0.048, respectively). One surviving patient was diagnosed with in-field fibrosarcoma, which was presumably radiation induced. Conclusions. Despite intensive, multiagent chemotherapy, survival from pelvic Ewing sarcoma has not improved over the past decade; however, the survival rate does not seem to be worse than that from Ewing sarcoma at other locations, insofar as at least 50% of the patients were cured. Surgery or a combination of surgery and radiation therapy are the best local treatment; exclusive radiation therapy should be reserved for patients with inoperable lesions or partially or nonchemosensitive tumors or when surgery would be an amputation. [References: 17] <24> UI - 1999384845 AU - Ciftcioglu N AU - Bjorklund M AU - Kuorikoski K AU - Bergstrom K AU - Kajander EO IN - Dr. N. Ciftcioglu, Dept. of Biochemistry/Biotechnology, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio; Finland. E-Mail: neva.ciftcioglu@uku.fi. TI - Nanobacteria: An infectious cause for kidney stone formation. SO - Kidney International Vol 56(5) (pp 1893-1898), 1999. AB - Background. Nanobacteria are cytotoxic, sterile-filterable, gram- negative, atypical bacteria detected in bovine and human blood. Nanobacteria produce carbonate apatite on their cell walls. Data on Randall's plaques suggest that apatite may initiate kidney stone formation. We assessed nanobacteria in 72 consecutively collected kidney stones from Finnish patients. Methods. Nanobacteria and kidney stone units were compared using scanning electron microscopy (SEM). Demineralized kidney stones were screened for nanobacteria using a double-staining method and a specific culture method. Isolated nanobacteria were analyzed for mineral formation in vitro with Ca and 85Sr incorporation tests. Results. SEM highlighted the resemblance in size and morphology of nanobacteria and the smallest apatite units in the kidney stones. Nanobacterial antigens could be detected after the demineralization of the stones in 1 N HCl. Nanobacteria were surprisingly resistant to this treatment, and cultures could be established from 93.1% of the stones. Only struvite stones had common bacteria, in addition to the nanobacteria. When the results of all of the assays were combined, 70 of the 72 stones (that is, 97.2%) were nanobacteria positive. Although apatite stones indicated highest nanobacteria antigen signals, the overall nanobacteria positivity did not depend on the stone type. The isolated nanobacteria produced apatite stones in vitro, measured by Ca and 85Sr incorporation. Conclusions. We propose that kidney stone formation is a nanobacterial disease analogous to Helicobacter pylori infection and peptic ulcer disease. Both diseases are initiated by bacterial infection and subsequently endogenous and dietary factors influence their progression. [References: 29] <25> UI - 1999370087 AU - Antonello S AU - Maran F IN - F. Maran, Dipartimento di Chimica Fisica, Universita di Padova, via Loredan 2, 35131 Padova; Italy. TI - The role and relevance of the transfer coefficient alpha in the study of dissociative electron transfers: Concepts and examples from the electroreduction of perbenzoates. SO - Journal of the American Chemical Society Vol 121(41) (pp 9668-9676), 1999. AB - The electrochemical transfer coefficient alpha is shown to be a sensitive probe of the mechanism by which electron transfer and bond cleavage may be coupled in dissociative electron transfers. alpha is particularly useful in detecting the transition between stepwise and concerted dissociative electron transfers. Whereas linear potential dependencies of alpha are in agreement with either mechanism, a mechanism transition can be evidenced upon observation of a nonlinear alpha pattern. Under favorable circumstances, a wavelike potential dependence of alpha can be observed. This is a function of main parameters describing the mechanism competition such as, in particular, the difference between the two relevant standard potentials, the intrinsic barriers, and the preexponential factors of the two rate-constant equations. The analysis of alpha was applied to study the electroreduction of a series of perbenzoates, XC6H4CO3Bu(t), in DMF. The reduction leads to the irreversible cleavage of the O-O bond. The alpha data were obtained by cyclic voltammetry followed by convolution analysis. For all compounds investigated, the experimental trend could be simulated satisfactorily by reasonable selection of the main parameters. Whereas the analysis showed that the reduction of the unsubstituted peroxide proceeds by a pure concerted mechanism, a stepwise mechanism holds when X = 4-NO2. On the other hand, alpha-wave patterns were found for X = 4-COMe and 3-NO2, as previously described for X = 4-CN. For the latter compounds, the alpha analysis is in agreement with a dissociative electron transfer process in which the mechanism changes from stepwise to concerted by increasing the applied potential. Finally, although the reduction of the 4-OCOMe perbenzoate basically occurs by a concerted mechanism, a transition pattern seems to emerge at the most negative potentials explored. Further support to the experimental outcome and conclusions was provided by studying the temperature effect on the reduction of the 4-COMe derivative, which led to the expected shift toward the stepwise mechanism by lowering the temperature. <26> UI - 1999367959 AU - Wellnhofer E AU - Combe V AU - Oswald H AU - Fleck E IN - Dr. E. Wellnhofer, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin; Germany. E-Mail: EWellnhofer@t-online.de. TI - High fidelity correction of pressure signals from fluid-filled systems by harmonic analysis. SO - Journal of Clinical Monitoring and Computing Vol 15(5) (pp 307-315), 1999. AB - Fluid-filled systems are generally used for invasive pressure measurements in cardiology, anesthesiology and intensive care medicine. Wave reflection and attenuation cause considerable signal distortion. Methods. The transducer signal is amplified (no filtering) and sampled (rate 1 kHz) using an autocorrelation based algorithm to detect instantaneous cycle length. A digital Fourier transformation (DFT) for each heart cycle is performed. Amplitude and phase distortion are corrected using data matrices determined in in vitro experiments or calibration measurements for each fluid-filled system to be used. As a measure for accuracy the maximum of the difference of reference and corrected pressures (DIFF) was selected. 900 analyses were performed to assess the impact of correction, used system mean pressure, time and A/D sampling rate on the agreement with reference pressure. Clinical examples are presented. Results. Mean pressure was correlated with DIFF (r = 0.83). The correction algorithm achieves a significant (p < 0.001) reduction of DIFF from 20-30 mm Hg to 0-5 mm Hg in the high pressure range and from 1-3 mm Hg to 0-1.5 mm Hg in the low pressure system in in vitro experiments and in clinical pressure recordings. Sampling frequency < 1 kHz reduces accuracy. Conclusions. High fidelity correction of pressure signals from fluid-filled systems by harmonic analysis is feasible. [References: 30] <27> UI - 1999344610 AU - Pelino JEP AU - Mello JB AU - Eduardo CP AU - Jorge AOC IN - J.E.P. Pelino, Av. Francisco Jose Longo, 777, 12201-970 Sao Jose dos Campos-SP; Brazil. E-Mail: pelinoj@dentistry.ucsf.edu. TI - In vitro study of the Nd:YAG laser effect on human dental enamel: Optical and scanning electron microscope analysis. SO - Journal of Clinical Laser Medicine & Surgery Vol 17(4) (pp 171-177), 1999. AB - Objective: The Nd:YAG laser irradiation of dental enamel was evaluated in enamel demineralization experiments in a Streptococcus mutans culture media. Summary Background Data: Previous studies had shown that a continuous wave Nd:YAG laser at an energy of approximately 67 mJ may induce an increased acid resistance in human dental enamel when exposed to severe demineralization conditions. Methods: Enamel windows of 3 x 4 cm in the buccal surface were irradiated with a continuous wave Nd:YAG laser at a wavelength of 1,064 mum using energy densities of from 83.75 to 187.50 J/cm2. Enamel windows of 3 x 4 cm on the lingual surface served as control (without the laser irradiation). The enamel windows were then exposed to a Streptococcus mutans culture media at a temperature of 37 [degree] C for 15 and 21 days. The laser effects and demineralization were examined both by optical microscopy and scanning electron microscopy (SEM). Results: A comparison between the lased and the unlased windows of enamel showed fusion and recrystalization of the enamel and increased acid-resistance in all groups irradiated with the Nd:YAG laser. On the other hand, the 3 x 4 delimited enamel surfaces from the control group (not irradiated with the Nd:YAG laser) showed 100% demineralization. Conclusions: These findings are consistent with the finding that laser irradiation of dental results in significant reduction of the effective solubility of enamel mineral. [References: 22] <28> UI - 1999321134 AU - Thurnheer T AU - Guggenheim B AU - Gruica B AU - Gmur R IN - R. Gmur, Inst. Oral Microbiol. Gen. Immunol., University of Zurich, Plattenstrasse 11, CH-8028 Zurich; Switzerland. E-Mail: gmuer@zzmk.unizh.ch. TI - Infinite serovar and ribotype heterogeneity among oral Fusobacterium nucleatum strains?. SO - Anaerobe Vol 5(2) (pp 79-92), 1999. AB - Fusobacterium nucleatum is part of the residential human microbiota and is associated with various infections. It is characterised by broad genetic heterogeneity, but reliable phenotypic markers are lacking. The purpose of the present study was to generate antibodies for the detection of F. nucleatum, to characterise expression patterns of the detected surface antigens on oral isolates, to investigate the prevalence of distinguishable subtypes in clinical samples from the oral cavity, and to compare antigenic with ribotype heterogeneity. Thirty-seven monoclonal antibodies (mAbs) were generated and characterised using strains from 52 taxa. Antibody-binding bacteria were monitored in 35 samples of supra- and subgingival plaque from healthy sites and sites affected by gingivitis or periodontitis. Results indicated broad but structured antigenic heterogeneity. Detecting at least 28 different epitopes, the mAbs defined 19 serovars. Epitopes were expressed on periodate-sensitive polysaccharide chains. Ribotyping of 40 oral F. nucleatum strains (PvuII digestion) resulted in the detection of similarly broad genetic heterogeneity, which rarely corresponded to the observed phenotypic diversity. Clinical samples were generally positive for multiple (up to eight) serovars of which some colonised supra- and subgingival plaques from both healthy and diseased sites, whereas others were restricted to inflamed sites. The majority of the studied isolates could not be grouped with reference strains of the five established subspecies of F. nucleatum, corroborating doubts about the usefulness of the current classification scheme. Although, as a whole the described monoclonal antibodies can only recognise a part of the overwhelming heterogeneity of this 'species', they should prove of value to investigations of the importance, the antigenic stability and the origin of positive subtypes of F. nucleatum from human infections. [References: 48] <29> UI - 1999285287 AU - Cook LJ IN - L.J. Cook, Agcy. for Hlth. Care Policy/Research, Department of Health/Human Services, 6000 Executive Boulevard, Rockville, MD 20852; United States. TI - The implications of protocol-based care on dental services in the military. SO - Military Medicine Vol 164(8) (pp 556-561), 1999. AB - Downsizing, limited resources, and increasing costs provide challenges to the military health system. Variations in the diagnosis and treatment of dental disease add to the demands on the delivery system to provide access and ensure quality for uniformed personnel. Evidence-based dentistry is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. An evidence-based practice combines individual clinical expertise with the best external evidence available from systematic review of research findings. It provides a scientific basis for patient care, planning and implementation of health services, and development of health policy. Practice guidelines formulated on scientific evidence can reduce variations in the diagnosis and treatment of various dental conditions. A risk assessment protocol for treating dental caries can reduce operative dental treatment recommended at the initial examination and decrease the need for restorative care during a military career. [References: 32] <30> UI - 1999271581 AU - Dowker SEP AU - Anderson P AU - Elliott JC IN - Dr. S.E.P. Dowker, Comprehensive Dental Care Section, St. Bartholomew's and Royal London, School of Medicine and Dentistry, Turner Street, London E1 2AD; United Kingdom. E-Mail: s.e.p.dowker@mds.qmw.ac.uk. TI - Real-time measurement of in vitro enamel demineralization in the vicinity of the restoration-tooth interface. SO - Journal of Materials Science-Materials in Medicine Vol 10(6) (pp 379-382), 1999. AB - An X-ray attenuation method using photon counting (scanning microradiography) is presented for the real-time study of in vitro demineralization of dental tissues in the vicinity of the restoration-tooth interface. By repeated measurement of mineral content profiles during the course of demineralization, the pattern of lesion development and the rate of mineral loss can be studied. The method is illustrated by comparison of enamel demineralization near a polyacid-modified composite resin restoration, near a bis-GMA/TEGMA composite resin restoration, and in an unrestored control. The method has potential for study of the influence of restorative materials on susceptibility of tooth tissue to demineralization. [References: 14] <31> UI - 1999262479 AU - Fann YC AU - Metosh-Dickey CA AU - Winston GW AU - Sygula A AU - Ramakrishna Rao DN AU - Kadiiska MB AU - Mason RP IN - Y.C. Fann, Lab. of Pharmacology and Chemistry, Natl. Inst. of Envtl. Hlth. Sciences, National Institutes of Health, 111 T. W. Alexander Dr., Research Triangle Park, NC 27709; United States. E-Mail: fann@niehs.nih.gov. TI - Enzymatic and nonenzymatic production of free radicals from the carcinogens 4-nitroquinoline N-oxide and 4-hydroxylaminoquinoline N-oxide. SO - Chemical Research in Toxicology Vol 12(5) (pp 450-458), 1999. AB - The anion radicals of 4-nitroquinoline N-oxide (4-NQO) and 4- nitrosoquinoline N-oxide (4-NOQO) carcinogens were detected and characterized by electron spin resonance (ESR) spectroscopy. The structures of the radical intermediates were examined by density functional theory (DFT) at the level of hybrid unrestricted uBecke3LYP. The formation of superoxide anion radical catalyzed by flavin-containing enzymes such as cytochrome P450 reductase or xanthine oxidase in the presence of 4-NQO or 4-nitroquinoline N-oxide was studied by spin-trapping experiments. In this case, the ESR signal of the 5,5-dimethyl-1-pyrroline N-oxide (DMPO)-superoxide radical adduct was observed, and its formation was inhibited by superoxide dismutase (SOD). No ESR signal was detected when the two-electron-transferring flavoenzyme DT- diaphorase (NADPH-quinone oxidoreductase) was used. The above is consistent with a one-electron reduction in the metabolism of these nitro compounds to anion free radicals by various flavoenzyme reductases. [References: 67] <32> UI - 1999238785 AU - Khodzhimetov TA AU - Gol'dfel'd MN IN - T.A. Khodzhimetov, Akadempribor Sci.-Mfg. Association, Academy of Sciences of Uzbekistan, Tashkent; Uzbekistan. TI - A device for studying electroexcitability of dental tissues. SO - Bio-Medical Engineering Vol 32(5) (pp 305-306), 1998. <33> UI - 1999236538 AU - Mehmanesh H AU - Bauernschmitt R AU - Hagl S AU - Lange R IN - Dr. H. Mehmanesh, Klinik fur Herz- und Gefasschirurgie, Deutsches Herzzentrum Munchen, Technische Universitat Munchen, Lazarettstr. 36, D-80636 Munchen; Germany. TI - A new concept in the treatment of supraventricular tachycardia after heart surgery: Internal low-energy cardioversion via a temporary atrial electrode. [German] SO - Zeitschrift fur Kardiologie Vol 88(6) (pp 434-441), 1999. AB - Supraventricular tachycardia (SVT) is a common complication early after cardiac surgery. A novel temporary atrial patch electrode (TAPE) for low energy atrial defibrillation was first implanted for intraoperative testing and subsequently removed during open heart surgery in 10 patients (Phase I). After the intraoperative testing period, the TAPE was implanted in 20 patients for postoperative termination of spontaneous episodes of supraventricular tachycardia (Phase II). In case of supraventricular tachycardia (SVT), biphasic shocks (1.2-5.0 J) were applied, measuring the atrial defibrillation thresholds. Phase I: The mean intraoperative atrial defibrillation threshold was 1.6 +/- 1.4 J with a mean shock-impedance of 64.0 +/- 7.3 Ohms. Phase II: Postoperatively, 6 out of 20 patients (30 %) developed 7 episodes of atrial fibrillation (n = 6) and atrial flutter (n = 1). In 5 patients, SVT could be converted to sinus rhythm (n = 5) or junctional rhythm (n = 1). The mean postoperative defibrillation threshold (DFT) was 2.7 +/- 2.1 J with a mean shock-impedance of 50.2 +/- 6.8 Ohms. In conclusion, the TAPE allows low-energy defibrillation of atrial fibrillation. It seems to be a useful alternative in the treatment of supraventricular tachycardia. [References: 33] <34> UI - 1999234132 AU - Coradini D AU - Oriana S AU - Biganzoli E AU - Marubini E AU - Boracchi P AU - Bresciani G AU - Di Fronzo G AU - Daidone MG IN - Dr. D. Coradini, UO Determ. Biomol. Prognosi Terapia, Dipartimento Oncologia Sperimentale, Istituto Nazionale Tumori, Via Venezian 1, 20133 Milano; Italy. E-Mail: coradini@istitutotumori.mi.it. TI - Relationship between steroid receptors (as continuous variables) and response to adjuvant treatments in postmenopausal women with node-positive breast cancer. SO - International Journal of Biological Markers Vol 14(2) (pp 60-67), 1999. AB - In current clinical practice for breast cancer patients, estrogen (ER) and progesterone receptor (PgR) concentrations, quantified by the dextran-coated charcoal assay, are categorized by an arbitrary cutoff into a negative or positive status. However although the results obtained with this approach are easy to interpret, such a representation could oversimplify the relationship between ER and PgR content and patient outcome and imply an assumption of monotonicity, which is generally expected but rarely proven. We evaluated the relationship between ER and PgR content (considered on a continuous scale) and clinical outcome, using a flexible statistical model, in a group of postmenopausal patients with N-positive operable tumors who were submitted to surgery and different adjuvant treatments (tamoxifen or CMF). Univariate analysis indicated that in the tamoxifen-treated group, ER level, number of metastatic nodes (pN) and age, but not PgR, were significant indicators of clinical outcome (p = 0.032, p = 0.021 and p = 0.029, respectively). Multivariate analysis indicated that in this group of patients there was no interaction between variables, and in the final model for disease-free survival (DFS) only ER and pN were retained with an overall predictive ability of the regression model of 0.723, as evaluated by Harrell's c. However, pN markedly contributed to the predictive ability of the model with respect to ER, since a marked decrease in Harrell's c statistic (c = 0.582) was observed when pN was removed from the model. In the CMF-treated group, only pN affected clinical outcome. When the estimated DFS curves obtained from the final Cox regression models were plotted according to four values of ER (in the tamoxifen-treated group) or three values of pN (in the CMF-treated group) we observed that in the tamoxifen-treated group patients with an ER concentration equal to 0 fmol/mg cytosol protein had the worst prognosis, whereas a marked improvement of the expected DFS was observed for patients with a low but detectable ER level (generally classified as ER-negative because falling below the conventional cutoff value of 10 fmol/mg cytosol protein). Our results seem to suggest that the use of steroid receptor concentrations on a continuous scale, instead of dichotomous 'status', is to be preferred in the choice of adequate therapeutic strategies. [References: 27] <35> UI - 1999220597 AU - Leonelli FM AU - Wang KE AU - King C AU - Brewer J AU - Donohoo AM AU - Kroll MW IN - Dr. F.M. Leonelli, KY Clinic, 740 South Limestone Street, Lexington, KY 40508-0284; United States. TI - Energy steering of biphasic waveforms using a transvenous three electrode system. SO - Pacing & Clinical Electrophysiology Vol 22(6 I) (pp 849-854), 1999. AB - The optimal electrode configuration for endocardial defibrillation is still a matter of debate. Current data suggests that a two pathway configuration using the right ventricle (RV) as cathode and a common anode constituted by a superior vena cava (SVC) and a pectoral can (C) is the most effective combination. This may be related to the more uniform voltage gradient created by shocks delivered using this configuration. We hypothesized that more effective waveforms could be obtained by varying the distribution of the shock current between the two pathways of a three electrode endocardial defibrillation system. In 12 pigs, we compared the characteristics and the defibrillation efficacy of six biphasic waveforms discharged using either a two (RV [right arrow] C) or a three (RV [right arrow] SVC + C) electrode combination with the following configurations: Configuration 1 (W1): the RV apical coil was used as a cathode and the subcutaneous C as anode (RV [right arrow] C). Configuration 2 (W2): The RV was used as cathode and the combination of the atriocaval coil (SVC) and the subcutaneous C as anode (RV [right arrow] SVC + C). Configuration 3 (W3): The RV [right arrow] C was used for the first 25% off + and RV [right arrow] SVC + C for the remainder of the discharge including f 2. Configuration 4 (W4): The RV [right arrow] C was used for the first 50% off + and RV [right arrow] SVC + C for the remainder of the discharge including f 2. Configuration 5 (W5): The RV [right arrow] C was used for the first 75% off + and RV [right arrow] SVC + C for the remainder of the discharge including f 2. Configuration 6 (W6): The RV [right arrow] C was used for f + and RV [right arrow] SVC + C for f 2. As an increasing fraction of the waveform was discharged using the RV [right arrow] SVC + C pathways, the impedance and the pulse width decreased while the tilt, the peak, and the average current significantly increased. The waveforms delivered using the RV [right arrow] SVC + C configuration for 100% or 75% of their duration had significantly lower stored energy DFT than the other waveform. Current distribution between three endocardial electrodes can be altered during the shock and generates waveforms with different characteristics. Shocks with 75% or more of the current flowing to the RV [right arrow] SVC + C required the lowest stored energy to defibrillate. This method of energy steering could be used to optimize current delivery in a three electrodes system. [References: 16] <36> UI - 1999199899 AU - Gimsa J IN - J. Gimsa, Institut fur Biologie, Humboldt-Universitat zu Berlin, D-10115 Berlin; Germany. TI - New light-scattering and field-trapping methods access the internal electric structure of submicron particles, like influenza viruses. SO - Annals of the New York Academy of Sciences Vol 873 (pp 287-298), 1999. AB - A variety of AC-electrokinetic field effects can be exploited for handling or electric characterization of microscopic and submicroscopic particles, like cells, organelles, supramolecular structures, and artificial colloids. Despite the fact that dielectric spectroscopy methods by AC-electrokinetics, like common impedance methods, are based on the impedance properties of the different constituents of the particles, the first methods yield higher parameter resolutions. A drawback of the electrokinetic methods was that they required microscopic observability of field-induced particle movements. New AC-electrokinetic methods like electrorotational light scattering (ERLS), dielectrophoretic phase-analysis light scattering (DPALS), and dielectrophoretic field trapping (DFT) solve this problem and access the submicroscopic particle range. This paper gives an introduction to the new methods and presents measurements on influenza viruses. To develop a dielectric virus model, experiments of ERLS were combined with DFT of viruses in microstructured electric-field cages. The model assumes a spherical virus with a radius of 50 nm and a single-shell dielectric structure. The shell thickness of 18 nm summarizes the dimensions of the lipid and viral surface protein layers. For this model, the conductivities of core and shell of 0.1 mS/m and 0.1 muS/m, respectively, and the relative permittivities of 30 and 80, respectively, were obtained. [References: 29] <37> UI - 1999189246 AU - Marchetti C AU - Poggi P AU - Cornaglia AI AU - Farina A AU - Rizzo S IN - C. Marchetti, Ist. Istologia Embriologia Generale, via Forlanini 10, 27100 Pavia; Italy. E-Mail: carla.marchetti@unipv.it. TI - Morphologic characteristics of initial lymphatics of the healthy and diseased human gingiva. SO - Anatomical Record Vol 255(2) (pp 175-179), 1999. AB - Investigation was performed on healthy and inflamed human gingivae. In the healthy mucosa lymphatic vessels generally appeared as flattened channels with a reduced lumen. Only in very inflamed tissue were some more evident vessels with a distended wall detectable. Ultrastructurally, most of the vessels had the characteristics of capillaries and they were delimited by a thin and irregular endothelial wall with large intercellular spaces. These observations indicate that in the gingival tissues, which are continuously exposed to inflammatory agents and need a really efficient draining system, the pathway of interstitial exudation and cell migration may include both the lymphatic vessel system and the intercellular spaces of the permeable junctional epithelium. [References: 21] <38> UI - 1999167538 AU - Curcio LD AU - Rupp E AU - Williams WL AU - Chu DZJ AU - Clarke K AU - Odom-Maryon T AU - Ellenhorn JDI AU - Somlo G AU - Wagman LD IN - Dr. L.D. Curcio, Surgical Oncology, 81st MSGS/SGCS, Keesler Medical Center, 301 Fisher Street, Keesler AFB, MS 39534; United States. TI - Beyond palliative mastectomy in inflammatory breast cancer - A reassessment of margin status. SO - Annals of Surgical Oncology Vol 6(3) (pp 249-254), 1999. AB - Background: Inflammatory breast cancer is a locally advanced tumor with an aggressive local and systemic course. Treatment of this disease has been evolving over the last several decades. The aim of this study was to assess whether current therapies, both surgical and chemotherapeutic, are providing better local control (LC) and overall survival (OS). We also attempted to identify clinical and pathologic factors that may be associated with improved OS, disease-free survival (DFS), and LC. Methods: A 25-year retrospective review performed at the City of Hope National Medical Center identified 90 patients with the diagnosis of inflammatory breast cancer. Results: Of the 90 patients identified with inflammatory breast cancer, 33 received neoadjuvant therapy (NEO) consisting of chemotherapy followed by surgery with radiation (n = 26) and without radiation (n = 7). Fifty-seven patients received other therapies (nonNEO). Treatments received by the nonNEO group consisted of chemotherapy, radiation, mastectomy, adrenalectomy, and oophorectomy, alone or in combination. The median follow-up was 28.9 months for the NEO group and 17.6 months for the nonNEO group. Borderline significant differences in the OS distributions between the two groups were found (P = .10), with 3- and 5- year OS for the NEO group of 40.0% and 29.9% and for the nonNEO group of 24.7% and 16.5%, respectively. DFS and LC were comparable in the two groups. Lower stage was associated with an improved OS (P < .05). The 5-year OS for stage IIIB was 30.9%, compared to 7.8% for stage IV. In those patients with stage III disease who were treated with mastectomy and rendered free of disease, margin status was identified by univariate analysis to be a prognostic indicator for OS (P < .05). The 3-year OS, DFS, and LC for patients with negative margins were 47.4%, 37.5%, and 60.3%, respectively, compared to 0%, 16.7%, and 31.3% in patients with positive margins. Conclusions: This study suggests that in patients with inflammatory breast cancer and nonmetastatic disease, an aggressive surgical approach may be justified with the goal of a negative surgical margin. Achievement of this local control is associated with a better overall outcome for this subset of patients. The ability to obtain negative margins may further identify a group of patients with a less aggressive tumor biology that may be more responsive to other modalities of therapy. [References: 25] <39> UI - 1999154593 AU - Holen S TI - Re: Current understanding of the role of microscopic monitoring, baking soda, and hydrogen peroxide in the treatment of periodontal disease (position paper) (1998;69: 951-954) (multiple letters). SO - Journal of Periodontology Vol 70(4) (pp 455-456), 1999. <40> UI - 1999127067 AU - Pizzocaro C AU - Lessard RA AU - Bolte M IN - M. Bolte, Unite Mixte de Recherche, Ctr. Natl. de la Rech. Scientifique, 6505 Clermont-Ferrand, 63177 Aubiere Cedex; France. E-Mail: boltem@cicsun.univbp-clermont.fr. TI - Charge-transfer phenomena in holographic recording material: Dichromated poly(acrylic acid). SO - Canadian Journal of Chemistry Vol 76(11) (pp 1746-1752), 1998. AB - Dichromated poly(acrylic acid) (DCPAA) has been used as real time holographic recording material. We report here the photochemical behavior of DCPAA when irradiated under conditions representative of those used for hologram recording. Under UV-vis spectroscopy a photoredox process (Cr(VI) [right arrow] Cr(III)) was observed whose efficiency depends on the presence of dimethylformamide (DMF) used as an electron donor. ESR spectroscopy upon irradiation permits detection of the formation of Cr(V) of photochemical origin. We also identified chromium(V) of thermal origin (in the dark), organic macroradicals, and chromium(III). The formation of CO2 and carboxylate ions was clearly shown by IR spectroscopy. The photoreaction is assumed to go through an acido-basic reaction between dichromate in the excited state and poly(acrylic acid). The resulting unstable chromium polyacrylate undergoes a redox process that gives rise to chromium(V) and a macroradical R-COO. from which CO2 is formed. The presence of DMF (10% by volume) makes the overall reaction faster by a factor of approximately 3.5- 4. The similar shape of the curves giving chromium(V) formation as a function of irradiation time and the curves giving the diffraction efficiencies of the hologram recorded in DCPAA as a function of exposure energy, with and without DMF, strongly argues in favor of a direct involvement of chromium(V) in the quality of the resulting hologram. [References: 17] <41> UI - 1999138693 AU - Grosgogeat B AU - Reclaru L AU - Lissac M AU - Dalard F IN - M. Lissac, School of Dentistry, University Claude Bernard of Lyon I, Rue Guillaume Paradin, 69372 Lyon Cedex 08; France. TI - Measurement and evaluation of galvanic corrosion between titanium/Ti6Al4V implants and dental alloys by electrochemical techniques and auger spectrometry. SO - Biomaterials Vol 20(10) (pp 933-941), 1999. AB - The purpose of this study was to investigate, in different experimental conditions, the galvanic corrosion phenomena which can exist between a dental suprastructure and a dental implant. The electrochemical behavior of 7 alloy superstructures with titanium and titanium alloy (Ti6Al4V) implants was investigated by electrochemical means in Fusayama-Meyer de-aerated saliva and Carter-Brugirard (AFNOR) non de-aerated saliva. Different techniques were used to obtain the value of the galvanic coupling current and potential for each couple. All showed very low corrosion rates, ranging from 10-6 to 10-8 A. Surface analysis confirmed these results. [References: 33] <42> UI - 1999118196 AU - Coppens P AU - Abramov Y AU - Carducci M AU - Korjov B AU - Novozhilova I AU - Alhambra C AU - Pressprich MR IN - P. Coppens, Department of Chemistry, State University of New York, Buffalo, NY 14260-3000; United States. TI - Experimental charge densities and intermolecular interactions: Electrostatic and topological analysis of DL-histidine. SO - Journal of the American Chemical Society Vol 121(11) (pp 2585-2593), 1999. AB - A high-resolution, low-temperature X-ray diffraction data set on DL- histidine, collected with a CCD detector, is used in the analysis of molecular bonding and intermolecular interactions. The molecular dipole moment in the crystal is enhanced relative to that from HF and DFT calculations. Topological properties of the molecular electron density differ from theory for the polar bonds but generally agree well for the C-C bonds in the molecule. A major aim of the study is the evaluation of the electrostatic contribution to the intermolecular interactions from the experimental density. The electrostatic interaction energies between pairs of neighboring molecules, as calculated from the experimental density, compare reasonably well with the total interaction energies from supermolecule calculations. The agreement is somewhat improved by the addition of nonelectrostatic repulsion and dispersive terms, which together contribute much less than the electrostatic energy. The electrostatic interaction energy calculated from the CHARMM point-charge force field is often close to the values derived from the experimental charge density, though exceptions occur. In an alternative approach, the topology of the intermolecular charge density is related to the intermolecular interaction energy. The latter approach makes use of a density functional by Abramov (Acta Crystallogr. 1997, A53, 264-272) and a relation between the potential energy density at the bond critical point and the hydrogen bond dissociation energy (Espinosa, et al. Chem. Phys. Lett. 1998, 285, 170-173). <43> UI - 1999105909 AU - Benhlima N AU - Turmine M AU - Letellier P AU - Naejus R AU - Lemordant D IN - D. Lemordant, Lab. Physico-Chimie des Interfaces, Milieux Reactionnels (EA 2098), Universite de Tours, Parc Grandmont, 37200 Tours; France. TI - Electrochemistry in fused ethylammonium nitrate at 298 K: Determination of a redox potential scale. [French] SO - J CHIM PHYS PHYS-CHIM BIOL, Vol 95(1) (pp 25-44), 1998. AB - Ethylammonium nitrate (NEA) is a room temperature fused salt, miscible with water and some organic solvents like methanol. Its ability to dissolve organic or inorganic compounds and its intrinsic conductance make it suitable for electrochemical analysis. The purpose of this article is to present some physical and electrochemical properties of this solvent. From the variations of the interfacial tension with the applied voltage, the potential of zero charge (E(pcn)) of the NEA/mercury interface has been inferred; the study of the electrocapillary curve shows that the negative charge born by the electrode at E UI - 1999100859 AU - Bento MF AU - Geraldo MD AU - Montenegro MI IN - M.I. Montenegro, Departamento de Quimica, Universidade do Minho, Largo do Paco, 4709 Braga Codex; Portugal. E-Mail: montenegro@ci.uminho.pt. TI - Effect of the medium composition on the current of steady state voltammograms of neutral and charged species in dimethylformamide/toluene mixtures. SO - Analytica Chimica Acta Vol 385(1-3) (pp 365-371), 1999. AB - Steady state voltammetric currents of both neutral and charged species obtained at microelectrodes are affected by the medium composition. Experiments carried out in N,N-dimethylformamide (DMF) and toluene/DMF mixtures for the reduction of dicyano(fluoren-9-ylidene)methane (DCN) and the methylviologen cation (MV2+) and for the oxidation of ferrocene (Fc), in the presence of different electrolyte concentrations indicate that both viscosity of the solution and mass transport by migration can have a strong effect on the measured limiting currents. These observations are particularly important in electroanalysis since the appropriate choice of the medium may substantially improve both sensitivity and detection limit of the electrochemical method. Copyright (C) 1999 Elsevier Science B.V. [References: 17] <45> UI - 1999101543 AU - Sommer MA AU - Tehovnik EJ IN - M.A. Sommer, Laboratory of Sensorimotor Research, N.E.I., National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892-4435; United States. E-Mail: mas@lsr.nei.nih.gov. TI - Reversible inactivation of macaque dorsomedial frontal cortex: Effects on saccades and fixations. SO - Experimental Brain Research Vol 124(4) (pp 429-446), 1999. AB - Neural recording and electrical stimulation results suggest that the dorsomedial frontal cortex (DMFC) of macaque is involved in oculomotor behavior. We reversibly inactivated the DMFC using lidocaine and examined how saccadic eye movements and fixations were affected. The inactivation methods and monkeys were the same as those used in a previous study of the frontal eye field (FEF), another frontal oculomotor region. In the first stage of the present study, monkeys performed tasks that required the generation of single saccades and fixations. During 15 DMFC inactivations, we found only mild, infrequent deficits. This contrasts with our prior finding that FEF inactivation causes severe, reliable deficits in performance of these tasks. In the second stage of the study, we investigated whether DMFC inactivation affected behavior when a monkey was required to make more than one saccade and fixation. We used a double-step task: two targets were flashed in rapid succession and the monkey had to make two saccades to foveate the target locations. In each of five experiments, DMFC inactivation caused a moderate, significant deficit. Both ipsi- and contraversive saccades were disrupted. In two experiments, the first saccades were made to the wrong place and had increased latencies. In one experiment, first saccades were unaffected, but second saccades were made to the wrong place and had increased latencies. In the remaining two experiments, specific reasons for the deficit were not detected. Saline infusions into DMFC had no effect. Inactivation of FEF caused a larger double-step deficit than did inactivation of DMFC. The FEF inactivation impaired contraversive first or second saccades of the sequence. In conclusion, our results suggest that the DMFC makes an important contribution to generating sequential saccades and fixations but not single saccades and fixations. Compared with the FEF, the DMFC has a weaker, less directional, more task-dependent oculomotor influence. [References: 59] <46> UI - 1999084591 AU - Murakawa Y AU - Yamashita T AU - Kanese Y AU - Sezaki K AU - Omata M IN - Dr. Y. Murakawa, Second Dept. of Internal Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113; Japan. TI - Is ventricular fibrillation interval an indicator of electrical defibrillation threshold?. SO - Pacing & Clinical Electrophysiology Vol 22(2) (pp 302-306), 1999. AB - To clarify whether peak-to-peak interval of the fibrillation wave (VF interval) during VF is an independent indicator of defibrillation efficacy, we measured the transcardiac DFT, VF intervals of the surface and local ECGs (lead II and the right ventricle), and the ERP in 82 open-chest dogs. Both VF intervals showed a negative correlation with heart weight (surface: r = - 0.358 [P < 0.005]; local: r = -0.349 [P < 0.005]). DFT was 2.0 +/- 0.7 A and positively correlated with heart weight (r = 0.453 [P < 0.0001]). ERP did not show a significant correlation with heart weight. DFT was negatively correlated with VF interval (vs surface VF interval: r = -0.568 [P < 0.0001]; vs local VF interval: r = -0.504 [P < 0.0001]), but showed only a weak negative correlation with ERP (r = -0.314 [P < 0.005]). Even after allowing for the dependency of DFT and VF intervals on heart weight (normalized to a 100-g heart), the correlation between VF interval and DFT was still significant (vs surface VF interval: r = -0.487 [P < 0.0001]; vs local VF interval: r = -0.414 [P < 0.0002]). These results suggest that VF interval is an indicator of DFT in intact hearts that have not received pharmacological intervention. [References: 22] <47> UI - 1999063179 AU - Weinberg MA AU - Bral M IN - M. Bral, Department of Periodontics, New York Univ. College of Dentistry, 345 East 24th Street, New York, NY 10010; United States. TI - Tetracycline and its analogues: A therapeutic paradigm in periodontal diseases. SO - Critical Reviews in Oral Biology & Medicine Vol 9(3) (pp 322-332), 1998. AB - This article discusses the use of tetracyclines in the clinical management of periodontal infections. A review of the drugs' pharmacology, pharmacokinetics, and potential adverse effects shows that they are relatively safe if used in appropriate dosages and under controlled conditions. Current data suggest that the routine use of tetracyclines in conjunction with the treatment of periodontitis is unnecessary. However, their distinctive characteristics can be utilized in different delivery systems as an adjunctive aid to conventional treatment of juvenile and refractory forms of periodontitis. [References: 95] <48> UI - 1999052131 AU - Lulic-Dukic O AU - Radionov D AU - Bukovic D AU - Verzak Z AU - Bagic I IN - O. Lulic-Dukic, Stomatoloski Fakultet Sveucilista, Gunduliceva 5, 10000 Zagreb; Croatia. TI - Trauma of decidual teeth and the most common consequences. SO - Paediatria Croatica Vol 42(3-4) (pp 153-157), 1998. AB - Dental trauma during the decidual dentition period can cause the impairment of their permanent replacements. Therefore, it is necessary to establish a diagnosis on time, to apply adequate therapy and to follow-up the patient over a period of time. Trauma of the teeth has an important place in current pedodontics, partly because of the constant increase in its prevalence. In spite of the considerable regeneratory potential of young individuals, teeth affected by trauma are more prone to exhibit various changes on their permanent replacements. Therefore, a multidisciplinary team approach is usually required in the management of this problem. Parents need to be informed about the most vulnerable period for dental trauma, and the most frequently involved circumstances of its occurrence. It would be of a great importance to develop a program of education for pre-school and school children, as well as for their teachers, which would lead to greater care during play, sport and other activities in childhood. There is no doubt that such a program would result in a considerable decrease in the incidence of dental trauma. [References: 14] <49> UI - 1999051158 AU - Zilo P AU - Weiss DN AU - Luceri RM IN - Dr. P. Zilo, Florida Arrhythmia Consultants, 1971 East Commercial Blvd., Fort Lauderdale, FL 33308; United States. E-Mail: rluceri@gate.net. TI - Late retesting of system performance in ICD patients without spontaneous shocks. SO - Pacing & Clinical Electrophysiology Vol 22(1 II) (pp 197-201), 1999. AB - One hundred five implantable cardioverter defibrillator (ICD) patients (71 +/- 9 years of age, 83% men) without spontaneous ICD discharges for >= 12 months were tested to assess high voltage (HV) circuit integrity and the system's ability to recognize and terminate ventricular fibrillation (VF). Indications for ICD implantation were sustained ventricular tachycardia (VT) (35%), cardiac arrest (27%), and inducible VT (38%). Eighty-two percent of the patients had coronary artery disease (CAD), and the mean left ventricular ejection fraction (LVEF) was 36% +/- 13%. Results: One hundred patients had inducible VF and five did not. Testing led to ICD reprogramming in 50 (49%) patients. Two (1.9%) patients required ICD replacement: (1) a 45-year-old patient with a Ventritex 110 ICD implanted for 13 months interfaced with a CPI 0062 lead implanted for 46 months could not be defibrillated internally (impedance nonmeasurable); (2) an 82-year-old patient with a 23-month-old Medtronic 7219 ICD interfaced with 6936 and 6933 leads whose defibrillation threshold (DFT) had doubled since implantation (24 J from 12 J). Lead fractures were found in both cases (proximal coil of the 0062, and subcutaneously in the 6933). Based on DFT determinations, the first shock output was programmed lower in 37 patients and higher in 10 patients. Shock pulse width was changed in one patient and the ventricular refractory period in another. No programming changes were made in 54 (51%) patients. Conclusions: (1) Late testing of HV circuit integrity in ICD patients without an ICD shock in >= 12 months identifies previously unsuspected HV lead fractures; (2) chronic DFT testing resulted in HV output reprogramming in one-half of the patients. [References: 9] <50> UI - 1999026671 AU - Sung K AU - Tidwell TT IN - K. Sung, Department of Chemistry, University of Toronto, Toronto, Ont. M5S 3H6; Canada. TI - Theoretical study of the reactivity of ketene with free radicals. SO - Journal of Organic Chemistry Vol 63(26) (pp 9690-9697), 1998. AB - The structures and energies for the addition of free radicals R. (R = H, CH3, OH, F, SiH3, Cl) to CH2=C=O to give the radicals RCH2C [.] =O, C [.] H2(C=O)R, CH2=C [.] OR have been calculated by ab initio and B3LYP-DFT methods, and the latter method gives good agreement with available experimental energies. Product radicals C [.] H2C(=O)R for groups R which possess electron lone pairs are stabilized and have predominant spin density on carbon, and this is attributed to conjugation of the carbonyl group in the product with substituents OH, F, and Cl at the alpha-position. Additions of H and SiH3 have lower barriers to form the more stable product RCH2C [.] =O, which for the latter is favored due to hyperconjugative stabilization by the beta-SiH3. For CH3 attack at both carbons is competitive, while for OH, F, and Cl, the barriers are low for attack at either carbon, although attack at C(alpha) gives much more stable products. Initial complexes between ketene and the CH3, OH, SiH3, and Cl radicals are detected, and for Cl using B3LYP this species has the structure of a pi-complex with the C=C double bond that is stabilized by 16.2 kcal/mol relative to the reactants and forms C [.] H2C(=O)Cl with a barrier of 2.8 kcal/mol. For F no barriers for addition to either carbon were found, but for B3LYP there is a barrier of 27.6 kcal/mol for conversion of FCH2C [.] =O to C [.] H2C(=O)F, which is more stable by 19.1 kcal/mol. The corresponding rearrangement of ClCH2C [.] =O has a barrier of 4.6 kcal/mol, and the predicted preference for initial attack at C(beta) to give the less stable product agrees with experiment. <51> UI - 1998420449 AU - Gorrel C IN - C. Gorrel, 17 Burnt House Lane, Pilley Nr Lymington, Hants S041 5QN; United Kingdom. TI - Periodontal disease and diet in domestic pets. SO - Journal of Nutrition Vol 128(12 SUPPL.) (pp 2712S-2714S), 1998. AB - Periodontal disease is the most common oral condition seen in domestic pets. In addition to the discomfort caused in the affected animal, there is strong circumstantial evidence to show that a focus of infection in the mouth may cause disease of distant organs. Consequently, prevention of periodontal disease is of paramount importance for the general health and well-being of pets. The presence of plaque on the tooth surfaces is the primary cause of periodontal disease. However, the mechanisms by which disease develops are by no means fully understood. Dietary texture does have an effect on the accumulation of dental deposits and consequently on disease development and progression. Daily toothbrushing remains the single most effective means of removing plaque, thus preventing periodontal disease. On the basis of current knowledge, the best way to maintain healthy periodontal tissues in our pets is frequent toothbrushing. The use of a dental hygiene chew and/or a diet designed to reduce dental deposits can be useful adjunctive measures and should be recommended. [References: 29] <52> UI - 1999000302 AU - Tsuda H AU - Jongebloed WL AU - Stokroos I AU - Arends J AU - Kodaka T AU - Suzuki M IN - H. Tsuda, Laboratory for Materia Technica, State University of Groningen, Bloemsingel 10, 9712 KZ Groningen; Netherlands. E-Mail: h.tsuda@med.rug.nl. TI - A micro-Raman spectroscopic study of hydrazine-treated human dental calculus. SO - Scanning Microscopy Vol 10(4) (pp 1015-1024), 1996. AB - Hydrazine has been used to remove organic components and to isolate the mineral(s) from human calculus. Micro-Raman measurements were performed on the mineral phase. After the hydrazine-treatment, not only a large reduction in fluorescence but also an increase in Raman signal was observed. The treatment was essential in minimizing thermally-induced chemical changes which could otherwise occur to the original calculus mineral due to the intense laser light. The Raman spectral features of the mineral were nearly all identical among the Raman spectra obtained at many randomly-selected sites by the micro-Raman microbe with a lateral resolution of approximately 1 mum, and were consistent with those of impure hydroxyapatite containing CO32- and HPO42-. The spectra contained typical hydroxyapatite bands including PO43- bands of the v1, v2, v3 and v4 modes and one OH- stretch band. Other minor bands due to the CO32- v1 and v3 modes and bands possibly due to the HPO42- v1, v2 and v4 modes were observable by the technique despite the hydrazine-treatment that could in principle remove the HPO4 and CO3 ions from the mineral. In comparison with pure synthetic hydroxyapatite, the intensity of the OH- stretch band relative to that of the PO43- v1 band was approximately 70% weaker, and the bandwidth of the phosphate v1 band was 200% broader, reflecting various crystal imperfections presumably present in the calculus mineral. [References: 29] <53> UI - 1998396808 AU - Nakanishi W AU - Hayashi S AU - Kusuyama Y AU - Negoro T AU - Masuda S AU - Mutoh H IN - W. Nakanishi, Dept. of Material Science/Chemistry, Faculty of Systems Engineering, Wakayama University, 930 Sakaedani, Wakayama 640-8510; Japan. TI - Why selenoxanthone gives an MC with bromine: An examination of electronic states of xanthones and xanthenes by electron spectroscopy and ab initio MO calculations. SO - Journal of Organic Chemistry Vol 63(23) (pp 8373-8379), 1998. AB - The PIES and UPS spectra of xanthone (1a), thioxanthone (1b), and selenoxanthone (1c) were measured, together with those of the corresponding xanthene (2a), thioxanthene (2b), and selenoxanthene (2c). Ab initio MO calculations were performed with the 6-311+G(d,p) basis sets at the DFT (B3LYP) level on 1a-c and 2a-c. The results of the measurements and of the MO calculations explained well the striking difference in the reactivity of the compounds, especially for 1c versus 2c. The ionization potentials (IP) of pi6(n) (HOMO), n(p(z)) (pi2(n) for 1a and 2a), and n(p(y)) were in the order IP(1a) > IP(1b) > IP(1c) and IP(2a) > IP(2b) > IP(2c). The IP of the xanthones were larger than those of the corresponding xanthenes. The IP of n(p(z)) of 1c was demonstrated to be larger than those of 2b and PhSPh (3b), which showed that 1c was less reactive than 2b and 3b toward electrophiles. These results accounted for the reactivity of 1c to give a molecular complex (MC) with bromine similar to the case of the MC structure of the sulfide dibromides. The relative intensity of PIES of HOMO in 1c was smaller than that in 2c. The electron density outside the molecular surface of the orbital of 1c must be smaller than that of 2c, due to the strong electron- withdrawing carbonyl group in 1c, which was supported by the calculated natural populations at the chalcogen atoms of the compounds. <54> UI - 1998395999 AU - Loesche WJ IN - W.J. Loesche, Univ. of Michigan Sch. of Dentistry, School of Medicine, Ann Arbor, MI; United States. TI - The diagnosis and treatment of anaerobic periodontal infections. SO - Infections in Medicine Vol 15(11) (pp 788-790+792-797), 1998. AB - Dental infections are the most common infections in humans, and periodontal disease is the primary dental problem for older individuals. Current management relies on periodic debridement of tooth surfaces for prevention and on surgery for advanced cases of periodontal disease. A new treatment paradigm is based on evidence that periodontal disease is a chronic but specific bacterial infection that can be treated by a combination of debridement and systemic and/or local delivery of antimicrobial agents, such as metronidazole. This article presents a brief review of the pathophysiology of periodontal disease, along with results from 3 double-blind clinical trials in which short-term metronidazole was used successfully in patients with advanced periodontal disease. [References: 57] <55> UI - 1998387684 AU - Slotwinska SM AU - Gorski A AU - Wierzbicka M AU - Dybizbanski E AU - Mrowiec T AU - Iwanicka-Frankowska E IN - S.M. Slotwinska, Department of Conservative Dentistry, Dental Institute, Medical University of Warsaw, 18 Miodowa Street, 00-246 Warsaw; Poland. E-Mail: Dentam1@WAW1.Comnet.PL. TI - T-cell interactions with extracellular matrix proteins in periodontal disease. SO - Immunology Letters Vol 63(3) (pp 131-134), 1998. AB - Lymphoid cell infiltration of periodontal tissues undergoing pathological destruction suggests a functional interdependence between connective tissue proteins such as collagen, fibronectin and elastin and mononuclear cells, mainly T lymphocytes. The aim of the study was to assess T lymphocyte proliferation after stimulation by mAb OKT3 and then costimulation by ECM (extracellular matrix) proteins, as well as T-cell adhesion to connective tissue proteins in patients with adult periodontitis, early-onset periodontitis, chronic gingivitis and experimental gingivitis. Controls included patients with clinically healthy periodontium. Statistical analysis of results showed a significantly decreased level of T lymphocyte proliferation in response to costimulating action of ECM proteins among patients with adult periodontitis as compared to the control group. Reactivity of T-cells was much higher in experimental gingivitis than in adult periodontitis, and significantly lower in chronic gingivitis than in controls. In addition, T-cell interaction with ECM proteins was abnormal in early-onset periodontitis patients, but was not statistically significant. [References: 16] <56> UI - 1998398116 AU - Schultz M AU - Kierdorf U AU - Sedlacek F AU - Kierdorf H IN - Dr. H. Kierdorf, Zoologisches Institut, Universitat zu Koln, Weyertal 119, D-50923 Koln; Germany. TI - Pathological bone changes in the mandibles of wild red deer (Cervus elaphus L.) exposed to high environmental levels of fluoride. SO - Journal of Anatomy Vol 193(3) (pp 431-442), 1998. AB - A macroscopic, microscopic and scanning electron microscope study was performed on the pathological bone changes of the mandibles of wild red deer (n = 61) exhibiting severe dental fluorosis. The animals originated from a highly fluoride polluted area in Central Europe (Ore mountains and their southern foreland, Czech-German border region) and constituted 11.2% of the studied red deer sample (n = 545) from this area. Pathologically increased wear and fracture of fluorosed teeth caused a variety of mandibular bone alterations, including periodontal breakdown, periostitis, osteitis and chronic osteomyelitis. As a further consequence of severe dental attrition, opening of the pulp chamber and formation of periapical abscesses were occasionally observed. In case of severe periodontal breakdown, loss of teeth from the mandibles was found. In addition to the inflammatory bone changes, the occurrence of osteofluorotic alterations was also diagnosed in the specimens with the highest bone fluoride concentrations (> 4000 mg F-/kg dry wt). These changes comprised extended apposition of periosteal bone onto the mandibular cortex as well as deformation of the mandibular body, which was attributed to a fluoride-induced osteomalacia. The present study provided circumstantial evidence that, in addition to fluoride induced dental lesions, the occurrence of marked periodontal disease and tooth loss is an important factor responsible for a reduction of life expectancy in severely fluorotic wild red deer. [References: 34] <57> UI - 1998388196 AU - Strom BL AU - Abrutyn E AU - Berlin JA AU - Kinman JL AU - Feldman RS AU - Stolley PD AU - Levison ME AU - Korzeniowski OM AU - Kaye D IN - Dr. B.L. Strom, Ctr. for Clinic. Epidemiol./Biostat., Blockley Hall, Univ. of Pennsylvania Sch. of Med., 423 Guardian Drive, Philadelphia, PA 19104-6021; United States. E-Mail: bstrom@cceb.med.upennedu. TI - Dental and cardiac risk factors for infective endocarditis: A population-based, case-control study. SO - Annals of Internal Medicine Vol 129(10) (pp 761-769), 1998. AB - Background: Although antibiotic prophylaxis against infective endocarditis is recommended, the true risk factors for infective endocarditis are unclear. Objective: To quantitate the risk for endocarditis from dental treatment and cardiac abnormalities. Design: Population-based, case-control study Setting: 54 hospitals in the Philadelphia area. Patients: Persons with community-acquired infective endocarditis not associated with intravenous drug use were compared with community residents, matched by age, sex, and neighborhood of residence. Measurements: Information on demographic characteristics, host risk factors, and dental treatment was obtained from structured telephone interviews, dental records, and medical records. Results: During the preceding 3 months, dental treatment was no more frequent among case-patients than controls (adjusted odds ratio, 0.8 [95% CI, 0.4 to 1.5]). Of 273 case-patients, 104 (38%) knew of previous cardiac lesions compared with 17 controls (6%) (adjusted odds ratio, 16.7 [CI, 7.4 to 37.4]). Case-patients more often had a history of mitral valve prolapse (adjusted odds ratio, 19.4 [CI, 6.4 to 58.4]), congenital heart disease (adjusted odds ratio, 6 7 [CI, 2.3 to 19.4]), cardiac valvular surgery (adjusted odds ratio, 74.6 [CI, 12.5 to 447]), rheumatic fever (adjusted odds ratio, 13.4 [CI, 4.5 to 39.5]), and heart murmur without other known cardiac abnormalities (adjusted odds ratio, 4.2 [CI, 2.0 to 8.9]). Among case-patients with known cardiac lesions-the target of prophylaxis-dental therapy was significantly (P=0.03) less common than among controls (adjusted odds ratio, 0.2 [CI, 0.04 to 0.7] over 3 months). Few participants received prophylactic antibiotics. Conclusions: Dental treatment does not seem to be a risk factor for infective endocarditis, even in patients with valvular abnormalities, but cardiac valvular abnormalities are strong risk factors. Few cases of infective endocarditis would be preventable with antibiotic prophylaxis, even with 100% effectiveness assumed. Current policies for prophylaxis should be reconsidered. [References: 29] <58> UI - 1998369117 AU - White JM AU - Adams GL AU - Matsumoto K AU - Myers TD IN - J.M. White, Department of Restorative Dentistry, University of California, 707 Parnassus, San Francisco, CA 94143-0758; United States. E-Mail: jwhite@itsa.ucsf.edu. TI - Microhardness and scanning electron microscopy analysis of Nd:YAG laser and acid treatment effects in dentin. SO - Scanning Microscopy Vol 10(2) (pp 329-337), 1996. AB - Laser irradiation at and above parameters producing the modification threshold for dentin causes structural changes to the dentin surface. This study determined the microhardness of dentin before and after laser modification and acid treatment using a repeated-measures design. Seven dentin sections (4 mm in thickness) were cut from freshly extracted non- carious third molars using a diamond saw. The middle occlusal third was used as the test dentin surface. One section served as a control (C); three received laser modification (L) and then acid treatment (L + A); and three received acid (A) and then laser treatment (A + L). Laser modification was made using a pulsed (120 mus) fiber-optic-delivered (500 mum diameter) Nd:YAG (lambda = 1.06 mum) laser at the physical modification threshold of 207 J/cm2. Acid treatment consisted of 10% nitric acid applied for 45 seconds. Twenty Knoop indentation microhardness measurements (KHN) were obtained using 300 g force engaged for 15 seconds for each section before and after each treatment (n = 400). Knoop microhardness values recorded: C = 62 +/- 3; L = 149 +/- 35;A = 24 +/- 5; L + A = 40 +/- 16; and A + L = 33 +/- 5. Multifactor-repeated measures, with analysis of variance (ANOVA; p <= 0.05), indicated significant differences between all treatment groups. Scanning electron microscopy analysis of dentin surfaces documented unique surface morphology for all treatment conditions. Laser modification of dentin before or after acid treatment increased dentin microhardness. [References: 48] <59> UI - 1998372962 AU - Marshall GW Jr AU - Wu-Magidi IC AU - Watanabe LG AU - Inai N AU - Balooch M AU - Kinney JH AU - Marshall SJ IN - Dr. G.W. Marshall Jr., Division of Biomaterials Science, Department of Restorative Dentistry, University of California, Parnassus Avenue, San Francisco, CA 94143-0758; United States. E-Mail: graymar@itsa.ucsf.edu. TI - Effect of citric acid concentration on dentin demineralization, dehydration, and rehydration: Atomic force microscopy study. SO - Journal of Biomedical Materials Research Vol 42(4) (pp 500-507), 1998. AB - Most current dentin bonding procedures use acid etchants to partially demineralize the dentin structure and provide pathways for resin infiltration. This study determined the recession rates of peritubular dentin and intertubular dentin as a function of pH during demineralization in citric acid solutions (0.0005-2.5M) and the effects of dehydration and rehydration on the partially demineralized dentin. Polished dentin disks were prepared with an internal reference layer and were studied at specific intervals for citric acid etching between pH 1 and 3.4 in an atomic force microscope. Peritubular dentin etched rapidly and linearly with time until it could no longer be measured. The intertubular surface began etching at nearly the same rate, but then recession slowed for all concentrations and stabilized after recession of less than 1 mum for all but the pH 1 solution. The decrease in recession was attributed to the limitation of contraction of the demineralized collagen scaffold as long as it remained hydrated. Dehydration following etching resulted in significant collapse of the surface, changes in roughness, and a slight decrease in tubule diameter' for samples etched for 30 min. Measurements could not be made of the collapse for low pH samples, because shrinkage stresses disrupted the integrity of the reference layer. On rehydration, the dehydrated surfaces underwent an expansion up to the level seen after etching and tubule diameters returned to the etched values. These results indicate that the collapse of demineralized matrix is almost totally recoverable on rehydration. [References: 29] <60> UI - 1998354020 AU - Sakai S AU - Urano S AU - Takatsuki H IN - S. Sakai, Environment Preservation Center, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto City; Japan. TI - Leaching behavior of persistent organic pollutants (POPs) in shredder residues. SO - Chemosphere Vol 37(9-12) (pp 2047-2054), 1998. AB - It is well known that some kinds of waste contain persistent organic pollutants (POPs) such as PCDD/DFs and PCBs. Leaching behaviors of these chemicals, however, have not been focused so much because of their low leachability. On the other hand, shredder residues originated from automobiles and electric appliances consist mainly of plastics, such as PVC, which contain additives including DEHP. In this study, contents analyses and leaching tests with and without surfactant-like substances for shredder residues were conducted. As a result, shredder residues from automobile and electric appliance contained PCBs in ppm level and a quantity of PCDD/DFs. Surfactant-like substances increase the leaching concentration of POPs. DEHP also leached out considerably even though using distilled water. [References: 6] <61> UI - 1998334496 AU - Murakawa Y AU - Yamashita T AU - Kanese Y AU - Omata M IN - Dr. Y. Murakawa, Second Dept. of Internal Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113; Japan. TI - Do the effects of antiarrhythmic drugs on defibrillation efficacy vary among different shock waveforms?. SO - Pacing & Clinical Electrophysiology Vol 21(10) (pp 1901-1908), 1998. AB - This study was designed to extend our knowledge on how pharmacological modification of defibr