PubMed Health⌕ Search

Biomedical subjects

S Belli

Publications and source records attributed to S Belli.

At least 37 records · Page 2Linked to original sources
PubMed2001

Bonding strength to two different surfaces of dentin under simulated pulpal pressure.

PURPOSE: The purpose of this in vitro study was to measure and compare the in vitro shear bond strengths (SBS) of the following dentin bonding systems to different dentin surfaces under simulated pulpal pressure: Liner Bond 2 (self-etching) (LB2), Liner Bond 2V (self-etching) (LB2V), Opti Bond Solo (single component) (OBS), Fuji Bond LC (filled) (FBLC), Prime & Bond 2-1 (single component) (P&B2-1), and Solid Bond (total etching) (SB). MATERIALS AND METHODS: Occlusal and buccal surfaces of 60 extracted human molars were prepared to expose the dentin bonding surface. After being wet ground with 600-grit abrasive papers, teeth were randomly assigned to 6 equal groups of 10 each. The dentin surfaces were treated with the bonding systems mentioned above, and resin composite cylinders (Clearfil AP-X) were built up under simulated pulpal pressure when diluted bovine serum was used as the pulpal fluid. After one day of storage in 37 degrees C water, the specimens were shear tested to failure on an Instron machine. RESULTS: The data were statistically analyzed with the Student's t-test and a post hoc Tukey test. Comparing buccal surfaces, the post hoc Tukey test indicated no significant differences among all the test groups (p > 0.05). On occlusal surfaces, the post hoc Tukey test indicated significant differences among the tested groups (p < 0.05). The Student's t test revealed significant differences between the occlusal and buccal shear bond strength values in LB 2, LB2V, and SB groups (p < 0.05). CONCLUSION: The strength of adhesion to dentin depends upon both the adhesive system used - with self-etching systems tending to show higher bond strengths than the other materials tested - and the location of the dentin, with significantly higher SBS being found on buccal surfaces in 3 of the 7 tested bonding systems.

Acid Etching, Dental↗
PubMed2000

Novel mutations of ubiquitin protein ligase 3A gene in Italian patients with Angelman syndrome.

Angelman syndrome is a neurobehavioral disorder caused by defects of imprinted gene(s) on chromosome 15q11-13. AS-specific DNA methylation is found in patients carrying 3-4 Mb deletions ( approximately 70%), paternal uniparental disomy (3-5%) or imprinting center mutations (2-9%), while normal methylation pattern with biparental inheritance characterizes the remaining approximately 20-25% AS patients (Stalker et al.,1998; Tsai et al.,1998). Mutations in the Ubiquitin protein ligase 3A gene (UBE3A) have been found in the latter group, but only preliminary figures are available on their frequencies. We selected a sample of 25 AS patients with a clinical diagnosis of AS and a normal methylation pattern in order to search for mutations of the UBE3A gene. Automated sequencing of exons 8, 9, 10, 11 and 12 performed on our 25 patients allowed us to identify three novel mutations: an 897insA in two unrelated familial cases, a 2544insA and an E167X in two sporadic cases. Mutation R482X previously reported in a sporadic patient was identified in a third familial case. Hum Mutat 15:387, 2000.

Adolescent↗
PubMed2000

Hyperfine Level Dependence of the Pressure Broadening of CH(3)I Rotational Transitions in the v(6) = 1 Vibrational State.

We studied the hyperfine components of the (J = 10-9, Kl = 9) rotational transition in the v(6) = 1 excited vibrational state of CH(3)I, using collinear infrared and mm-wave radiations. The Doppler-free double-resonance technique allowed an accurate determination of the collisional broadening parameters for all the hyperfine components. An evident dependence on the F quantum number was observed and this result is perfectly consistent with a theoretical model allowing calculations of collisional broadening and coupling for the hyperfine components. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

An autosomal dominant form of hereditary hypotrichosis simplex maps to 18p11.32-p11.23 in an Italian family.

We report on a three-generation Italian family with dominant transmission of a form of hereditary hypotrichosis simplex (HHS). The nine affected adults presented with sparse, thin and short hair. Somewhat less sparse and longer hair was observed in the two affected young children in the third generation. Reduced hair growth affected the scalp and body, although normal eyelashes, eyebrows and growth of men's beards were observed. No associated abnormality was detected and the overall psychomotor development of the affected individuals was normal. A phenotypic variation was observed amongst the family members and is suggestive of a reduced penetrance of the trait or the effect of a modifying factor. After exclusion, in our family, of linkage to loci previously described in other forms of atrichia or hypotrichosis, we performed a genome-wide linkage analysis, which resulted in a positive lod score at 18p11.32-p11.23. We defined a critical region of about 35 cM flanked by markers D18S853 and D18S40. The highest two-point lod score was obtained with the microsatellite markers D18S1376, D18S53 and D18S453 (lod score of 3.31 at theta = 0.00). The 18p11.32-p11.23 locus represents the first chromosome region shown to be associated with hereditary hypotrichosis simplex.

Adult↗
PubMed2000

A simple method for single anterior tooth replacement.

PURPOSE: This article reports a case in which a recently extracted tooth was used as a natural tooth pontic bonded to the teeth on either side of the missing tooth using a Ribbond ribbon. MATERIALS AND METHODS: A bondable, reinforcing polyethylene ribbon was used to bond a natural tooth pontic to adjacent teeth. RESULTS: Acceptable esthetics were obtained and the result was satisfactory for the patient. CONCLUSION: After one year of clinical use, direct construction of a single-tooth replacement using the natural tooth pontic still provided satisfactory esthetics and function. The technology which makes this adhesive restoration possible is the development of a high strength, high molecular weight, biocompatible polyethylene fiber. This easily handled material must be evaluated in long-term clinical studies.

Acid Etching, Dental↗
PubMed1999

Cohort mortality study of women compensated for asbestosis in Italy.

BACKGROUND: The carcinogenic effect of asbestos is accepted for lung cancer and mesothelioma, while conflicting opinions exist for other cancer sites. The aim of the present investigation is to study cause-specific mortality of women compensated for asbestosis who had certainly been exposed to high levels of asbestos fibers. METHODS: The cause-specific mortality of all Italian women compensated for asbestosis and alive December 31, 1979, was investigated through October 30, 1997. In the total cohort, which included 631 subjects, 277 deaths occurred. Cause-specific SMRs (Standardized Mortality Ratio) were computed using the national rates for comparison. RESULTS: A significantly increased mortality for all diseases related to asbestos exposure was observed. Mortality for all causes, all neoplasms, lung cancer, uterine cancer, ovarian cancer, and non-neoplastic respiratory diseases was significantly increased. Separate analyses for textile (n = 276) and asbestos-cement (n = 278) workers were performed. Women employed in the textile industry, mainly exposed to chrysotile, who are compensated at a younger age, showed higher SMRs for lung cancer and asbestosis. Women in the asbestos-cement industry, mainly exposed to crocidolite containing asbestos mixtures, experienced higher mortality for pleural malignancies. CONCLUSIONS: The role of asbestos exposure in the development of gastrointestinal and genital neoplasms is discussed.

Adult↗
PubMed1999

Leishmania major: histone H1 gene expression from the sw3 locus.

Histone H1 in the parasitic protozoan Leishmania is a developmentally regulated protein encoded by the sw3 gene. Here we report that histone H1 variants exist in different Leishmania species and strains of L. major and that they are encoded by polymorphic genes. Amplification of the sw3 gene from the genome of three strains of L. major gave rise to different products in each strain, suggesting the presence of a multicopy gene family. In L. major, these genes were all restricted to a 50-kb Bg/II fragment found on a chromosomal band of 1.3 Mb (chromosome 27). The detection of RFLPs in this locus demonstrated its heterogeneity within several species and strains of Leishmania. Two different copies of sw3 (sw3.0 and sw3.1) were identified after screening a cosmid library containing L. major strain Friedlin genomic DNA. They were identical in their 5' UTRs and open reading frames, but differed in their 3' UTRs. With respect to the originally cloned copy of sw3 from L. major strain LV39, their open reading frames lacked a repeat unit of 9 amino acids. Immunoblots of L. guyanensis parasites transfected with these cosmids revealed that both copies could give rise to the histone H1 protein. The characterization of this locus will now make possible a detailed analysis of the function of histone H1 in Leishmania, as well as permit the dissection of the molecular mechanisms governing the developmental regulation of the sw3 gene.

Amino Acid Sequence↗
PubMed1999

Mortality due to asbestos-related causes among railway carriage construction and repair workers.

The objective of this study was to further clarify the cancer risk associated with asbestos exposure in railway carriage construction and repair. The cohort included 734 subjects employed between 1 January 1945 and 31 December 1969. Vital status was ascertained at 31 December 1997. Mortality was investigated in the time span 1970-97. Forty-two subjects (6%) were lost to follow-up and eight causes of death (4%) could not be ascertained. The overall mortality was not above the expected value. Among neoplastic diseases, excesses were observed for lung ştandardized mortality ratio (SMR) = 124; 90% confidence interval (CI) = 87-172; 26 obs), pleura (SMR = 1,327; CI = 523-2,790; 5 obs), larynx (SMR = 240; CI = 95-505; 5 obs), liver (SMR = 241; CI = 126-420; 9 obs), pancreas (SMR = 224; CI = 98-443; 6 obs) and multiple myeloma (SMR = 429; CI = 117-1,109; 3 obs). The observed excess of lung and pleural neoplasms can be causally related to asbestos exposure in the manufacture of railway carriages. A causal role of asbestos exposure in the raised SMRs from laryngeal and pancreatic neoplasms and multiple myeloma cannot be conclusively proven.

Adult↗
PubMed1997

A homozygous mutation in the integrin alpha6 gene in junctional epidermolysis bullosa with pyloric atresia.

The alpha6 integrin subunit participates in the formation of both alpha6beta1 and alpha6beta4 laminin receptors, which have been reported to play an important role in cell adhesion and migration and in morphogenesis. In squamous epithelia, the alpha6beta4 heterodimer is the crucial component for the assembly and stability of hemidesmosomes. These anchoring structures are ultrastructurally abnormal in patients affected with junctional epidermolysis bullosa with pyloric atresia (PA-JEB), a recessively inherited blistering disease of skin and mucosae characterized by an altered immunoreactivity with antibodies specific to integrin alpha6beta4. In this report, we describe the first mutation in the alpha6 integrin gene in a PA-JEB patient presenting with generalized skin blistering, aplasia cutis, and defective expression of integrin alpha6beta4. The mutation (791delC) is a homozygous deletion of a single base (C) leading to a frameshift and a premature termination codon that results in a complete absence of alpha6 polypeptide. We also describe the DNA-based prenatal exclusion of the disease in this family at risk for recurrence of PA-JEB. Our results demonstrate that, despite the widespread distribution of the alpha6 integrin subunit, lack of expression of the alpha6 integrin chain is compatible with fetal development, and results in a phenotype indistinguishable from that caused by mutations in the beta4 chain, which is expressed in a more limited number of tissues.

Antigens, Surface↗
PubMed1997

Sinonasal cancer and occupation. Results from the reanalysis of twelve case-control studies.

A pooled reanalysis of twelve case-control studies on sinonasal cancer and occupation from seven countries was conducted in order to study associations with occupations other than wood- and leather-related occupations. The pooled data set included a total of 930 cases (680 men and 250 women) and 3,136 controls (2,349 men and 787 women). All the studies included a detailed occupational history for cases and controls. Each job was coded using the same classifications for occupation and industry. Two approaches were used in the analysis: systematic analysis of occupations; a priori analysis using a preestablished list of occupations and industries. The results confirmed associations observed in several studies not included in this analysis. For agricultural workers, significant excesses were observed for squamous cell carcinoma among women (OR = 1.69) and men (OR = 3.72 for ten years or more of employment as an orchard worker), and adenocarcinomas among men (OR = 2.98 for ten years or more of employment). Associations with textile occupations were observed for adenocarcinoma among women (OR = 2.60) and squamous cell carcinoma among men (OR = 5.09 for fiber preparers, 3.01 for bleachers). Elevated risks for both histologic types were observed among men employed in food manufacturing (OR = 3.25, adenocarcinoma), or as food preservers (OR = 13.9, squamous cell carcinoma), and among men employed as cooks (OR = 1.99, squamous cell carcinoma). A positive association with squamous cell carcinoma was observed for male transport equipment operators (OR = 1.21), and also with adenocarcinoma for male motor-vehicle drivers (OR = 2.50). A number of other associations were observed in the systematic analysis.

Adenocarcinoma↗
PubMed1997

Cohort mortality study of rubber and plastics product makers in Italy.

A retrospective cohort mortality study was carried out in 20 industrial factories in the Local Health Unit Bologna Sud (Emilia Romagna, Italy), where different rubber and plastics products were manufactured. The cohort consisted of 925 subjects (578 males and 347 females) employed for at least six months continuously; follow-up was between the beginning of operation of each factory, ranging between mid fifties and mid seventies, and 31 December 1989. For those exposed more than one year cause specific Standardized Mortality Ratios (SMRs) were computed using regional rates for comparison, 90% confidence intervals (CI) were calculated assuming the Poisson distribution. Among the 748 subjects employed for more than one year (457 males and 291 females) there were no lost to follow-up, 54 individuals were dead (41 males and 13 females) and for three subjects the cause of death was unknown. The results showed that all causes mortality was above expectancy in the total cohort (SMR = 123; 54 Obs; 90% CI = 97-154), among males (SMR = 117; 41 Obs; 90% CI = 89-152) and females (SMR = 143; 13 Obs; 90% CI = 85-228). Increased mortality for all malignant tumours was observed in the total cohort (SMR = 150; 25 Obs; 90% CI = 104-209) and for both genders. All nine lung cancer cases were observed among males, the SMR was equal to 218 and was statistically significant; seven cases occurred at duration of exposure less than 10 years and six at latency up to 20 years. The interpretation in terms of causality of the present investigation is limited by the small number of observations and by exposure definition solely in terms of employment in the study factories; nonetheless the results are indicating the existence, in this group of rubber and plastics product makers, of an adverse health effect which deserve further investigation.

Adult↗
PubMed1997

Colour stability of three esthetic laminate materials against to different staining agents.

The purpose of the present study was to evaluate the colour stability of three laminate veneer materials against to tea, coffee and cigarette smoke. 72 discs prepared by using two different type composite materials and a dental porcelain were divided into groups and immersed into distilled water, tea, Turkish coffee solutions. The last group was exposed to cigarette smoke. Colour differences were measured by colorimeter at the beginning and then in the period of 1 day, 1 week and 1 month respectively. As a result, it was found that cigarette smoke was the most staining agent, porcelain material was the most colour stable material, and indirect composite material was more colour stable than the direct one.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1997

An in vitro test model for investigation of disinfection of dentinal tubules infected with Enterococcus faecalis.

The aim of the present study was to develop an in vitro test model from human teeth to comparatively examine antibacterial effectiveness of calcium hydroxide, parachlorophenol (PCP) and camphorated parachlorophenol (CPCP) against Enterococcus faecalis in infected root canals. Cylindrical dentin specimens were prepared from freshly extracted human maxillary anterior teeth. The specimens were inoculated with E. faecalis and then medicated with either CPCP, PCP or Ca(OH)2. The disinfecting efficacy of these agents was tested by collecting dentin chips from the inner ("canal") walls of the specimens and counting viable E. faecalis. The dentin chips were diluted and a classical bacterial count technique was used for recovery of E. faecalis strains of 5% sheep blood agar. The effectiveness of CPCP and PCP at one day was superior to the effectiveness of Ca(OH)2. In the three-day group, CPCP was the most effective, followed by Ca(OH)2. The experimental model used in this study may be useful for investigation of the effect of intracanal medicaments on microorganisms lodged in the root dentinal tubules.

Calcium Hydroxide↗
PubMed1996

Psychiatric disorder in a familial 15;18 translocation and sublocalization of myelin basic protein of 18q22.3.

Two related patients with similar clinical features consisting of a few dysmorphic signs and psychiatric disturbance were reported to have a partial trisomy of chromosomes 15(pter-q13.3) and 18(q23-qter) deriving from a familial translocation t(15;18). One patient is affected by bipolar disorder and the other by schizoaffective disorder. Both cases have a predominantly affective course; nevertheless, a clear diagnosis is difficult in the first patient, who is 15 years of age, and only a longitudinal course will allow us to establish a definite diagnosis. The possibility that these two pathologies belong to a single category is discussed, and the presence of a susceptibility locus on chromosome 18 is hypothesized. Cytogenetic data, FISH, and DNA studies indicate that the myelin basic protein (MPB) gene is not involved in the translocation, and localize it centromeric to the breakpoint on chromosome 18(q22.3). Thus, it is unlikely to be involved in the disease.

Adolescent↗
PubMed1995

Wood dust and sino-nasal cancer: pooled reanalysis of twelve case-control studies.

In order to examine the relationship between wood dust and sino-nasal cancer, data from 12 case-control studies conducted in seven countries were pooled and reanalyzed. The relative risks associated with wood-related jobs and with exposure to wood dust, measured using a job exposure matrix based on occupation and industry titles, were examined using logistic regression. The combined data set consisted of 680 male cases, 2,349 male controls, 250 female cases, and 787 female controls. A high risk of adenocarcinoma among men was associated with employment in wood-related occupations (odds ratio [OR] = 13.5, 95% confidence interval [CI] = 9.0-20.0) and the risk was greatest among men who had been employed in jobs with the highest wood dust exposure (OR = 45.5, 95% CI = 28.3-72.9) and increased with duration of exposure. The risk of adenocarcinoma also appeared elevated among women employed in wood-related jobs (OR = 2.5, 95% CI = 0.5-12.3), but the small number of exposed cases precluded detailed analysis. Women in wood dust-exposed jobs appeared to have an excess of squamous cell carcinoma (OR = 2.1, 95% CI = 0.8-5.5) which increased with duration of exposure. An increased risk of squamous cell carcinoma in men was seen only among those employed for 30 or more years in jobs with exposure to fresh wood (OR = 2.4, 95% CI = 1.1-5.0). The results of this analysis provide strong support to the association between exposure to wood dust in a variety of occupations and the risk of sino-nasal adenocarcinoma and are consistent with the results of individual participating studies, although the magnitude of the excess risk varied. The evidence in regard to squamous cell carcinomas was ambiguous and there was a great deal of heterogeneity observed in individual study results. This may be due to differences in risk associated with exposure to hardwoods and softwoods or with other, as yet to be identified, aspects of exposure.

Adenocarcinoma↗
PubMed1994

Mortality study on a cohort of Italian licensed pesticide users.

This study describes the mortality experience in a cohort of 23,401 farmers, residing in southern Piedmont, Italy, and licensed to use pesticides. From 1970 to 1986 the cohort included 340,794 person-years and 2683 deaths were observed. A strong attenuation of the death risk was found due to the healthy worker effect (seen as an active role in the application for the license by the members of the cohort) and due to the limited comparability of the cohort with respect to the reference population. The standardized mortality ratios (SMRs) were remarkably < 100 for all causes (SMR = 59; 95% confidence interval = 57-61) and for all tumors (SMR = 60; 95% CI 55-64), but they increased with the increasing duration of the follow-up. A risk increase was observed with respect to melanomas and eye tumors in the entire cohort and lymphoma and tumors of the connective tissue in the subcohort of subjects living in villages with mainly arable land.

Adolescent↗
PubMed1994

Mortality study of asbestos cement workers.

The present study describes cause-specific mortality of asbestos cement workers in the Emilia Romagna region of Italy. The cohort included workers in ten factories, most of which started operating between 1955 and 1965. Asbestos, mainly chrysotile, constituted 10%-20% of the dry component of the mixture. Crocidolite range between 5% and 50% of total asbestos. Asbestos concentrations up to 44 ff/cc were reported prior to 1975, while in recent years they have usually been below 0-1 ff/cc. The cohort included 3341 workers who had at some time been employed in the ten factories under study. Their mortality experience was compared with that of the population resident in Emilia Romagna. Vital status was ascertained at 1989. Seventy-three subjects were lost to follow-up (2.2%). Mortality from all causes and from all types of cancer was increased in the cohort. Malignant neoplasms of the respiratory tract showed a significant increase (SMR: 134; 90% confidence interval: 101-175; 40 observed) due to lung cancer (SMR: 124; 90% confidence interval: 91-166; 33 observed) and neoplasms of the pleura, mediastinum, and other parts of the respiratory tract (SMR: 602; 90% confidence interval 237-1267; 5 observed). The discrepancy between observed and expected mortality mainly concerned subjects with at least 20 years of employment in the factories. Five more cases of histologically confirmed mesothelioma occurred after the end of follow-up.

Asbestos↗