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Biomedical subjects

L Levin

Publications and source records attributed to L Levin.

At least 19 recordsLinked to original sources
PubMed2006

Human immunodeficiency virus-infected patients with prior Pneumocystis pneumonia exhibit increased serologic reactivity to several major surface glycoprotein clones.

Recombinant clones of the carboxyl terminus of the major surface glycoprotein (MsgC) of Pneumocystis jirovecii are useful for analyzing serologic responses in humans. However, there is no standardized set of antigens in general use, which could lead to conflicting results. We have previously shown that human immunodeficiency virus type 1 (HIV-1)-infected patients with prior Pneumocystis pneumonia (PcP+) responded more frequently and more strongly to a clone of MsgC than did HIV-1-infected patients without PcP (PcP-). Here we test three new clones of MsgC to determine the effect of antigenic sequence variation on immune reactivity in blood donors and HIV-infected patients previously analyzed for reactivity to our original MsgC clone. In Western blot analyses, PcP+ patients exhibited the highest frequency of reactivity to each MsgC clone, and the frequency of reactivity with all four MsgC clones together was significantly higher in sera from PcP+ patients than in sera from the other patient groups. Furthermore, in an enzyme-linked immunosorbent assay we found that the PcP+ population had the highest level of reactivity to two of the four clones tested. One of the new clones could distinguish between PcP+ and PcP- populations, and two MsgC clones could distinguish blood donors from the other patient populations. The results show that inherent differences in MsgC amino acid sequence can affect recognition by antibodies independently of variations in protein length or patient population, and the utility of a clone depends on its sequence and on the populations tested.

Amino Acid Sequence↗
PubMed2006

Dental status among native and immigrant young Israeli adults.

BACKGROUND: New immigrants, originating from different cultures, often demonstrate dental health, behavior and treatment levels, which are different to native born populations. Immigrants are often classified as 'high-risk' populations. The goals of this study included comparing caries prevalence levels and different modes of treatment and dental health behavior, among immigrants from the former USSR and Israeli born young adults. METHODS: 581 young adults (average age 18 years) answered a questionnaire and were clinically examined. RESULTS: Socio-demographic variables were significantly different: number of siblings and years of schooling were higher among the Israeli born population; father's occupation was less professional among the immigrants. Untreated caries and lower father's occupation were significantly associated. Most immigrants reached the dentist's office only when they suffered pain, in contrast to the Israelis who were more regularly taken care of. Smoking was more prevalent among immigrants and significantly associated with caries levels. The caries prevalence among the Israelis was: DMFT = 4.7 +/- 4.13, D = 1.09 +/- 1.81, M = 0.11 +/- 0.37, F = 3.51 +/- 3.85, and among the immigrants: DMFT = 5.98 +/- 4.66, D = 2.78 +/- 2.77, M = 1.01 +/- 0.51, F = 2.70 +/- 3.22. These differences were statistically significant (p<0.005). CONCLUSIONS: Immigrants should be considered as a high risk group and demand a specific call for public health action.

Adolescent↗
PubMed2006

[Atrophic ridge augmentation using intra-oral onlay bone grafts--expanding the limits].

Placement of an endosseous implant requires sufficient bone volume for complete bone coverage. There is a growing use of intraoral block bone grafts from intraoral sources. The use of bone from the mandibular symphysis, retromolar area, mandibular ramus, and the maxillary tuberosity can serve as a good treatment alternative for alveolar ridge augmentation with a high success rate for long span augmentation, up to complete jaw augmentation or extensive bone reconstruction. The intraoral block bone graft procedure can be combined with other surgical procedures, such as sinus lift elevation or nasal floor elevation.

Alveolar Bone Loss↗
PubMed2006

[Decision making of Hebrew University and Tel Aviv University Dental Schools graduates in every day dentistry--is there a difference?].

This study was designed to evaluate decision-making among Jerusalem Hebrew-University and Tel Aviv University dental schools graduates in various restorative dentistry, endodontics and oral surgery issues. A survey was conducted among 52 dentists during a dental military convention. Most of the dentists stated they will not recommend of re-treatment of endodontic-treated tooth with asymptomatic peri-apical pathology that does not need further rehabilitation. The study reveals over treatment and over-medication in restorative and surgery decisions. More than half of the dentists decided to treat caries lesions that extend to the dentino enamel junction, in low and moderate caries risk patients. More Hebrew University graduates than Tel Aviv University graduates recommend of removal of asymptomatic horizontal fully impacted mandibular third molar and disease-free maxillary third molar antagonist. Most of Tel Aviv graduates routinely prescribe antibiotic coverage after complicated tooth extraction. This study supports the need for continuing education on daily performed dental procedures.

Antibiotic Prophylaxis↗
PubMed2005

A pilot study to investigate the effects of combined dehumidification and HEPA filtration on dew point and airborne mold spore counts in day care centers.

UNLABELLED: Meteorological factors such as relative humidity directly correlate with airborne fungal levels outdoors and indoors. While dehumidification alone is effective at reducing moisture necessary for mold growth, it is inadequate as a single intervention as it does not remove viable and non-viable fungal spores that are potentially allergenic. The purpose of this pilot study was to investigate whether dehumidification in combination with high-efficiency particulate arrestance (HEPA) filtration is effective at reducing airborne mold spore levels in day care centers. Two day care centers within a 2-mile radius of each other were selected. Day care center A was 2 years old with eight rooms while day care center B was 15 years old with six rooms. A high efficiency Santa Fe dehumidification unit equipped with a HEPA filter was installed in half the rooms (intervention) of each day care facility. Electronic HOBO data loggers continuously measured outdoor and indoor room dew point and temperature every 2 h throughout the study. Dew point and airborne fungal spore measurements from selected rooms with controlled air conditions were analyzed by comparing baseline measurements to those obtained at subsequent time periods over 1 year. Regression models accounted for correlations between measurements in the same room over time. Intervention resulted in a lowered average dew point from baseline by 8.8 degrees C compared with a decrease of 7.1 degrees C in non-intervention rooms across all time periods in both facilities (P<0.001). Fungal analyses demonstrated lower baseline (P=0.06) and follow-up means in intervention rooms (P<0.05), however the change from baseline to end of follow-up differed between intervention and non-intervention rooms in the two facilities. Log transformation was applied to approximate normality of fungal measurements. Dehumidification with HEPA filtration was effective at controlling indoor dew point in both facilities and at reducing airborne culturable fungal spore levels in one of the two facilities. These preliminary results provide a scientific rationale for using this intervention in future studies designed to investigate the impact of indoor mold exposure on health outcomes. PRACTICAL IMPLICATIONS: Poor indoor air quality is a recognized cause or contributing factor to health effects. Dampness and humidity have been linked to upper and lower respiratory symptoms in children and adults. This study indicates that reducing indoor relative humidity and airborne mold spore levels using high-efficiency dehumidification units equipped with HEPA filtration is feasible even in work facilities such as day care centers where traffic in and out of the building is difficult to regulate. Clinicians should emphasize to their patients the importance of dehumidification and HEPA filtration to improve indoor air quality in the home and workplace.

Air Pollution, Indoor↗
PubMed2005

[Oral hygiene, caries status and bad breath among young Israeli recruits].

The purpose of the present study was to evaluate the extent of self-reported bad breath in an Israeli population of young army recruits and to assess its relationship with other self-reported parameters, as well as general dental status. Self-reported parameters included smoking status, bad taste, gingival bleeding and the presence of tonsilloliths. The study comprised 426 young adults recruits (ages 18-19), almost all males (95%), all of whom agreed to answer a questionnaire. All participants underwent a dental screening and were divided into three groups regarding to their dental status (do not need treatment, need moderate treatment, need extensive treatment). Statistical analysis included Pearson's chi square test of association using BMDP statistical software. Among the recruits, 142 (33%) were active smokers. Thirty-five participants (8.2%) reported bad breath as well as bad taste. Twenty-seven (6.3%) reported being told that they had bad breath. Tonsilloliths were reported by 31 participants (7.3%) and gingival bleeding by 80 (18.8%). Self-reported bad breath was positively associated with bad taste, gingival bleeding, the presence of tonsilloliths and general dental status (p<0.05). The study indicates that self reports of bad breath are associated by objective factors (e.g. dental status, tonsilloliths) as well as subjective parameters (bad taste).

Adolescent↗
PubMed2005

[Limited mouth opening, xerostomia and extensive caries after nasopharyngeal carcinoma].

This report describes a 19 year old trainee with a history of Nasopharyngeal Carcinoma (NPC), a rare malignancy with distinct epidemiological, histopathological and clinical characteristics. During a screening for dental status, the soldier presented a limited mouth opening (25 mm), xerostomia, and extensive caries. Despite his resistance, he was referred to the TMJ unit in order to examine the reason for the limited mouth opening. During the anamnesis it was revealed that he suffered from NPC and was treated using chemotherapy and radiation therapy 6 month prior to the examination. This case emphasizes the importance of a thorough anamnesis and examination in order to discover such phenomenon, since withholding medical information is a well known phenomenon, especially among recruits and young soldiers. Unusual findings such as limited mouth opening, xerostomia and extensive caries, should be further examined. In this case a specialist's opinion is prompt, and until the definitive answer, treatment should be restricted to palliative dental treatment only, excluding any surgical procedure.

Adult↗
PubMed2005

[Smoking as a risk factor for dental implants and implant-related surgery].

Cigarette smoking is known to adversely affect wound healing, and thus may jeopardize the success of dental implantation and implant-related oral surgery. The present study is aimed to present the influence of cigarette smoking on the success and survival of dental implantation as well as on the complication and success of implant-related surgery. We conclude that smokers undergoing both implant-related surgical procedures and dental implantation should be encouraged by their dentists, oral and maxillofacial surgeons, or treating physicians to cease smoking, emphasizing that smoking can increase complications and reduce the success rate of these procedures.

Dental Implantation, Endosseous↗
PubMed2005

[Prevalence of congenitally missing teeth in Israeli recruits].

AIM: To evaluate the prevalence of congenitally missing teeth in a population of 18-year old Israeli army recruits. PATIENTS AND METHODS: The study population consisted of 226 out of 280 random 18-year-old Israeli army male recruits. The panoramic radiographs of those who fitted the criteria were examined by two dentists. The absence of permanent teeth in those radiographs was recorded. RESULTS: The prevalence of tooth agenesis (including the third molars) was 43.8%. The prevalence of tooth agenesis excluding the third molars was 5.3%. There were 11 subjects (4.2%) with a missing lower 2nd pre-molar, 3 subjects (1.1%) presented congenitally missing maxillary lateral incisors. As for the third molars, 101 subjects (5.83%) presented hypodontia of at least one third molar. Hypodontia of lower third molar was more common than hypodontia of upper third (22.1% and 16.4% respectively). 20 subjects (7.6%) presented bilateral mandibular missing third molars, 13 (4.9%) presented bilateral maxillary missing third molars and nine (3.4%) presented combined bilateral maxillary and mandibular missing third molars. CONCLUSION: The prevalence of tooth agenesis in Israeli army recruits was found within the wide range of reported similar data in the literature with some unique characteristics to this population.

Adolescent↗
PubMed2004

Evaluation of Argentinean white rot fungi for their ability to produce lignin-modifying enzymes and decolorize industrial dyes.

The decolorizing capacity of 26 white rot fungi from Argentina was investigated. Extracellular production of ligninolytic enzymes by mycelium growing on solid malt extract/glucose medium supplemented with different dyes (Malachite Green, Azure B, Poly R-478, Anthraquinone Blue, Congo Red and Xylidine), dye decolorization and the relationship between these two processes were studied. Only ten strains decolorized all the dyes, all ten strains produced laccase, lignin peroxidase and manganese peroxidase on solid medium. However, six of the strains could not decolorize any of the dyes; all six strains tested negative for lignin peroxidase, and produced less than 0.05 U/g agar of manganese peroxidase. Comparing the isolates with the well-known dye-degrader Phanerochaete chrysosporium, a new fungus was identified: Coriolus versicolor f. antarcticus, potentially a candidate for use in biodecoloration processes. Eighteen day-old cultures of this fungus were able to decolorize in an hour 28%, 30%, 43%, 88% and 98% of Xylidine (24 mg/l), Poly R-478 (75 mg/l), Remazol Brilliant Blue R (9 mg/l), Malachite Green (6 mg/l) and Indigo Carmine (23 mg/l), respectively. Laccase activity was 0.13 U/ml, but neither lignin peroxidase nor manganese peroxidase were detected in the extracellular fluids for that day of incubation.

Argentina↗
PubMed2004

The relation of Graves' ophthalmopathy to circulating thyroid hormone status.

AIM: The risk factors and epidemiological data for Graves' ophthalmopathy with and without abnormal circulating thyroid levels were examined to determine the relation of thyroid dysfunction to ophthalmopathy. METHODS: The authors retrospectively evaluated 482 patients seen with Graves' ophthalmopathy. Of these, 413 were classified as having abnormal levels of circulating thyroid hormone (ALTH) and 69 as having normal levels of circulating thyroid hormone (NLTH). RESULTS: Patients in the NLTH group, compared to the ALTH group, were older on average (56 (SD 13.5) v 52 (15.4)) and had a higher age adjusted body mass index (26.1 (0.8) v 23.4 (0.3)). In addition, a higher percentage of NLTH patients had hypercholesterolaemia. Those in the ALTH group were more likely to be female (76% v 51%), to have a family history of thyroid problems, and to have had eye surgery. CONCLUSION: NLTH and ALTH appear to differ from each other in terms of risk factors and epidemiological characteristics. Additionally, thyroid dysfunction seems to be associated with a more severe ophthalmopathy compared to the euthyroid state.

Adult↗
PubMed2003

Optimization of a culture medium for ligninolytic enzyme production and synthetic dye decolorization using response surface methodology.

A Box-Wilson central composite design was applied to optimize copper, veratryl alcohol and l-asparagine concentrations for Trametes trogii (BAFC 212) ligninolytic enzyme production in submerged fermentation. Decolorization of different dyes (xylidine, malachite green, and anthraquinone blue) by the ligninolytic fluids from the cultures was compared. The addition of copper stimulated laccase and glyoxal oxidase production, but this response was influenced by the medium N-concentration, with improvement higher at low N-levels. The medium that supported the highest ligninolytic production (22.75 U/ml laccase, 0.34 U/ml manganese peroxidase, and 0.20 U/ml glyoxal oxidase) also showed the greatest ability to decolorize the dyes. Only glyoxal oxidase activity limited biodecoloration efficiency, suggesting the involvement of peroxidases in the process. The addition of 1-hydroxybenzotriazole (a known laccase mediator) to the ligninolytic fluids increased both their range and rate of decolorization. The cell-free supernatant did not decolorize xylidine, poly R-478, azure B, and malachite green as efficiently as the whole broth, but results were similar in the case of indigo carmine and remazol brilliant blue R. This indicates that the mycelial biomass may supply other intracellular or mycelial-bound enzymes, or factors necessary for the catalytic cycle of the enzymes. It also implies that this fungus implements different strategies to degrade dyes with diverse chemical structures.

Alcohol Oxidoreductases↗
PubMed2003

Effect of minocycline on healing of replanted dog teeth after extended dry times.

Minocycline is available as a locally administered tetracycline derivative antibiotic (Arestin, OraPharma, Inc., Warminster, PA, USA) which demonstrated antibacterial activity and anti-inflammatory action that may slow down resorptive processes after severe traumatic injuries to the dentition. A total of 48 premolar roots of six mongrel dogs were instrumented in an aseptic fashion with rotary nickel-titanium files and obturated with vertically condensed warm gutta percha. All accesses were sealed with glass ionomer, the roots extracted and then allowed to bench dry for 60 min. Group 1 consisted of 15 roots that were coated with minocycline and replanted and nine roots that were replanted without minocycline. Group 2 consisted of 24 roots, all of which were prepared with a uniform cemental defect down to sound dentin along the lateral aspect of the root, with a high-speed bur following the 60-min dry time. Half of the roots (12) were then coated with minocycline and replanted, and the other 12 roots were replanted without minocycline. After 4 months, the dogs were killed and the roots prepared for histological evaluation. About 5- microm thick cross-sections of the root and surrounding tissue taken every 90 microm were evaluated for healing. In addition, residual root mass was also measured in the roots of group 1 to determine the extent of root structure loss for each treatment method. The roots with and without minocycline treatment showed no significant differences between the remaining root mass or the percentage of favorably healed root surfaces. The use of minocycline is not currently recommended for prevention or attenuation of external root resorption following avulsion in a dog trauma model.

Animals↗
PubMed2002

Effect of immediate intracanal placement of Ledermix Paste(R) on healing of replanted dog teeth after extended dry times.

Ledermix Paste is a paste containing triamcinolone and demeclocycline with demonstrated anti-inflammatory activity that may slow down resorptive processes after severe traumatic injuries to the dentition. A total of 29 premolar roots of six mongrel dogs were extracted and instrumented with rotary nickel titanium files. Fifteen of these roots were then filled with a calcium hydroxide (Ca(OH)2) slurry and 14 roots were filled with Ledermix Paste paste. All accesses were sealed with glass ionomer and the roots replanted after an extraoral dry time of 60 min. After 4 months, the dogs were killed and the roots prepared for histological evaluation. Five-micrometer thick cross-sections of the root and surrounding tissue taken every 90 micro m were evaluated for healing. In addition, residual root mass was also measured to determine the extent of root structure loss for each treatment method. The Ledermix Paste-treated roots had statistically significantly more healing and less resorption than the roots treated with Ca(OH)2. Root filling with Ledermix Paste also resulted in significantly less loss in root mass due to resorption compared to those roots filled with Ca(OH)2. Immediate intracanal placement of Ledermix Paste at the emergency visit after an avulsion injury appears to decrease resorption and increase favorable healing.

Animals↗
PubMed2001

Diagnostic yield of screening colonoscopies in lung transplant candidates.

BACKGROUND: Colonoscopy has been used to screen lung transplant candidates for colorectal diseases that would preclude transplantation. The diagnostic yield of this procedure is unknown. METHODS: This is a retrospective cohort study of patients 50 years of age and over who underwent lung transplant evaluations from 1996 to 1999. We assessed the prevalence and location of colonoscopic abnormalities, the predictive value of risk factors for colonic neoplasms, and the impact of colonoscopic findings on management. RESULTS: Thirty-one patients were evaluated. Twenty-four patients had at least one abnormal endoscopic finding. Six patients (19%) had adenomatous polyps; no carcinomas were detected. The 13 patients with risk factors were more likely to have adenomas (relative risk=2.8, P=0.2). The negative predictive value of risk factors for adenomas was 89%. One patient's management was altered and none were denied transplant listing because of the colonoscopic findings. CONCLUSIONS: Screening colonoscopy did not substantively alter the management of lung transplant candidates. More selective screening strategies may be warranted.

Adenoma↗
PubMed2001

Incident pregnancy rates in HIV infected and HIV uninfected at-risk adolescents.

PURPOSE: To compare pregnancy incidence between HIV infected and HIV uninfected adolescents over a 3-year period and to characterize factors that differentiate pregnant from nonpregnant HIV infected females. METHODS: Female adolescents enrolled in Reaching for Excellence in Adolescent Care and Health (REACH), a national cohort study, and nonpregnant at baseline comprised the sample (n = 345). Subject information on pregnancy, risk behavior, and psychosocial characteristics was obtained through interview, chart review, physical examination and laboratory data collected every 3 months. Incident pregnancy rate was analyzed using Cox proportional hazards modeling; the predictors of incident pregnancy were evaluated using repeated measures analysis. RESULTS: Ninety-four pregnancies were identified over 3 years. No significant difference in pregnancy incidence was detected between HIV infected and uninfected females (20.6 and 28.4 per 100 person-years, respectively, p = .16). However, for adolescents with living children at entry, HIV infected females were significantly less likely to become pregnant than HIV uninfected (HR = .45; p = .03). Among HIV infected adolescents, significant predictors of incident pregnancy were older age (p = .01) and not using hormonal contraception (p = .00), whereas increased spiritual hope and passive problem-solving capacity were protective against pregnancy (p = .02, and.05, respectively). Multivariate analysis revealed pregnancy prior to study entry to be predictive for (OR = 3.0; 95% CI: 1.2-7.7), and increased spiritual hope to be protective (OR = .4; 95% CI: .2-.9) against incident pregnancy in HIV infected females without the hormonal contraceptive variable in the model. CONCLUSIONS: The pregnancy rate is high in this study population. Further research is needed into its determinants and attenuating factors, particularly the role of spiritual elements, to design better contraceptive services and reproduction-related education targeting high-risk youth.

Adolescent↗