Search PubMed⌕ Search

Biomedical subjects

S J Silverstein

Publications and source records attributed to S J Silverstein.

53 records · Page 3Linked to original sources

Latent papillomavirus and recurring genital warts.

After anogenital condylomata and intraepithelial neoplasms are removed, they frequently recur. Since these lesions are related to papillomaviruses, it has been suggested that latent papillomavirus infection is responsible for recurrence. We studied 20 cases of anogenital lesions that were treated by laser therapy and analyzed biopsy specimens of margins of normal skin adjacent to the lesions for papillomavirus sequences by Southern blot hybridization. In nine cases (45 per cent), papillomavirus sequences were detected in the normal skin margin; lesions recurred in 6 of the 9 patients (67 per cent), in contrast to only 1 of 11 patients (9 per cent) whose margins were negative for the presence of papillomavirus sequences. All but one recurrence developed within 15 mm of the treatment area. Our results demonstrate that clinically and histologically latent papillomavirus exists beyond the treatment area and that its presence influences subsequent recurrences.

Animals↗

Dental X-ray exposure in a group of New Zealand children.

The New Zealand School Dental Service provides dental care for children 2 1/2-13 yr of age, without using routine diagnostic radiographs. This study investigated the pattern of dental X-ray exposure in groups of New Zealand children. One group consisted of 100 children who had all treatment before the age of 13 years with the School Dental Service. The other group consisted of 82 children who were treated in the University of Otago School of Dentistry paedodontic programme. Children in both groups turned 13 years of age between 1977 and 1982. From age 13 years these children were cared for by contracting dentists. Radiographic histories were recorded from School of Dentistry charts, and from the area Principal Dental Officer. Cumulative radiation doses were calculated. Surfaces restored at age 13 were noted from Department of Health records. Results show that by age 13 children enrolled in the School of Dentistry paedodontic programme received a mean cumulative skin dose of 23.03 mSv. Thyroid dose was 0.242 mSv. Children treated in the School Dental Service received a mean cumulative skin dose of 1.01 mSv and a thyroid dose of 0.006 mSv. Cumulative radiation dose for both groups was low. There was no significant difference in the mean number of restorations placed at age 13 years despite an extremely low level of diagnostic radiography in the School Dental Service group.

Adolescent↗

Dental caries prevalence in children with a diet free of refined sugar.

A study of the caries and dental hygiene status of 73 children living in the Synanon community revealed a mean DMF-S score at 0.53 for the 5-10 year old group and 3.33 for the 11-17 year old group. In spite of poor oral hygiene, 53 per cent of the children were caries-free and none of the children was missing permanent teeth. The children had consumed a diet free of refined carbohydrates for five years and had received optimal fluoride supplementation since birth or joining Synanon.

Adolescent↗

Evidence suggestive of compartmentalization of deoxyribonucleic acid-synthesizing systems in freeze-treated Bacillus subtilis.

Freezing of Bacillus subtilis in liquid nitrogen results, upon thawing of the cells, in an enhanced deoxyribonucleoside triphosphate and reduced thymidine (Tdr) incorporation into cellular deoxyribonucleic acid (DNA). The DNA synthesized from thymidine triphosphate (TTP) was made by a "repair"-type system as determined by density transfer experiments. The mono- and diphosphate precursors were also incorporated by a "repair"-type synthesis. When Tdr was used as the radioactive precursor in the assay mixture, the product was only that expected from a semiconservative synthesis. Superlethal ultraviolet light exposure of the freeze-treated cells stimulated incorporation of phosphorylated precursors into DNA. Tdr uptake was greatly reduced by ultraviolet exposure, and only repair synthesis was observed. TTP and Tdr do not compete with one another in this system. The possibility that two DNA synthesizing systems exist in separate, non-mixing cellular compartments is considered.

Bacillus subtilis↗

Computer-facilitated nutritional analysis.

A seven-day dietary analysis of 59 students in the dental health profession indicated that their nutrient consumption was generally adequate. A dental health examination indicated excellent oral hygiene. Nevertheless, many students were deficient in specific nutrient categories. Results suggested that computerized nutritional analysis techniques have general applicability in dental practice and epidemiological testing.

Ascorbic Acid↗