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Biomedical subjects

A Levinson

Publications and source records attributed to A Levinson.

32 records · Page 2Linked to original sources
PubMed1978

Supervised weekly rinsing with a 0.2% neutral NaF solution: results from a demonstration program after two school years.

The implementation of a school-based mouth-rinsing program in a Long Island, NY, community was described. In this program, children rinse once a week with a neutral 0.2% sodium fluoride solution under the supervision of homeroom teachers. Although the children reside in a fluoride-deficient community (F less than or equal to 0.1 ppm), the baseline dental caries prevalence of a subsample of the group (11 to 13 years old) was similar to that of comparably aged children who were residents of a fluoridated community and from approximately a third to a half lower than that of other fluoride-deficient communities. Despite the initially low caries activity in the study population, there was a 19.9% difference in mean DMFT prevalence scores between the baseline and two-year examination and a 20.3% difference in DMFS scores after two years of rinsing (average of 49 rinses). The greatest difference, 40.0%, was found between proximal surfaces; differences for occlusal and buccolingual surfaces were 19.6% and 15.6%, respectively.

Adolescent↗
PubMed1978

Experience with the lathe cut Bausch & Lomb SOFLENS: Part 1--Clinical study.

This study consists of clinical experience with the recently produced lathe cut Bausch & lomb SOFTLENS. Sixteen patients were fitted with the spin cast and then lathe cut lens. Visual acuities were better with the lathe cut lens. Comfort was good with both lenses. Some degree of circum-corneal injection was noted with the larger lathe cut design.

Adolescent↗
PubMed1978

Experience with the lathe cut Bausch & Lomb Soflens: Part II--Power and optics study.

Ten familiar spin cast and ten lathe cut Bausch & Lomb SOFLENS contact lenses were measured as to their power on a lensometer and on an eye. Both quality of the optics and quantitative measurements were considered. Lens flexure and the presence of a fluid lens between the posterior surface of the contact lens and the anterior cornea is indicated for both lenses to explain differences between power of the lens in air and on the eye. The spin cast lens design appears to create a quantitatively larger fluid lens, and one which will add positive optical power to the lens/eye system. Either from this and/or additional factors, the lathe cut lens appears to give improved optical performance both in air and on the eye.

Contact Lenses, Hydrophilic↗
PubMed1977

Ultrasonographic refraction of aphakic infants and children.

A simple method of aphakic refraction using ultrasonographic axial length measurement and corneal curvature determination is presented. This method was compared with skiascopy in refraction eleven eyes of aphakic infants. No significant differences were found between the relative errors measured by these two methods.

Cataract Extraction↗
PubMed1977

Use of the Bausch & Lomb Soflens Plano T contact lens as a bandage.

Twenty patients with corneal disease were treated with a recently released soft lens specifically designed for use as a bandage. Patients wore their lenses continuously 24 hr a day. The results were similar to those of previous studies conducted with other lens designs. Improvement was frequent (10 of 12 cases) for bullous keratopathy and corneal graft, burn, or neuroparalytic lesion; limited (1 of 4 cases) for dry-eye syndrome; and absent (4 cases) for irregular cornea and vernal keratoconjunctivitis. No difficulties were found with the concurrent use of medication.

Adolescent↗
PubMed1976

Characterization of an adenovirus early protein required for viral DNA replication: a single strand specific DNA binding proteins.

1. The human adenoviruses types 2, 5 and 12 code for the production of a single strand specific DNA binding protein. The molecular weights of these proteins were 72,000 for types 2 and 5 and 60,000 for type 12. In all three cases proteolytic breakdown fragments of these binding proteins (48,000 MW) were also observed. 2. Analysis of the methionine containing tryptic peptides of these proteins indicate that the types 2 and 5 proteins are similar and clearly distinguishable from the type 12 protein. The peptide maps of these three viral proteins are clearly different from a similar protein found in mock infected cells. 3. Temperature sensitive mutants of type 5 (H5ts125) and type 12(H12tsA275) adenoviruses fail to produce these proteins at the nonpermissive temperature. H5ts125 infected cells grown at the permissive temperature produce a 72,000 MW protein that is thermolabile, for continued binding to DNA, when compared to type 5 wild type adenovirus 72,000 MW protein. An analysis of the phenotype of this adenovirus mutant indicates that it codes for a viral function at early times after infection that is required for viral DNA replication. 4. The in vitro translation of adenovirus specific m-RNA results in the synthesis of a small amount of a 72,000 MW protein that binds to single stranded DNA just like the authentic adenovirus DNA binding proteins produced in infected cells. 5. Adenovirus anti-Tumor antigen (T) anti-serum from hamsters carrying independently derived adenovirus tumors, have been tested for the presence of antibody to purified DNA binding proteins. One antiserum is positive for these antibodies while the other is negative. These results indicate that some, but not all, adenovirus tumors contain large enough levels of the DNA binding proteins to elicit an antibody response. 6. The type 5 adenovirus temperature sensitive mutant, H5ts125, that codes for a thermolabile DNA binding protein, was complemented or suppressed at the nonpermissive temperature, for the replication of adenovirus DNA, by SV40. SV40tsA temperature sensitive mutants, defective in SV40 DNA replication, do not suppress or complement H5ts125 at the nonpermissive temperature.

Adenoviridae↗
PubMed1976

The relationship between group C adenovirus tumor antigen and the adenovirus single-strand DNA-binding protein.

The group C adenoviruses code for a single-strand specific DNA-binding protein of molecular weight 72,000 daltons which is synthesized at early times after productive viral infection. Experiments were designed to determine whether this single-strand specific DNA-binding protein was expressed in adenovirus tumors and transformed cells. Two independently derived preparations of anti-sera from hamsters bearing group C adenovirus tumors were tested for antibody against the single-stranded DNA-binding proteins. One antiserum contained antibodies that reacted with these DNA-binding proteins, while the second antiserum did not contain detectable levels of antibody. Five adenovirus type 2 transformed rat cell lines were tested for the presence of the single-stranded specific DNA-binding proteins. Two of the five transformed cells expressed detectable levels of this protein. These results indicate that the group C adenovirus single-strand specific DNA-binding proteins are expressed in some, but not all, adenovirus tumors and transformed cell lines. Those transformed cell lines (type 2) containing a portion of the adenovirus genome designated by the Eco R-I-B restriction enzyme fragment express the single-strand specific DNA-binding proteins. Those cell lines missing this Eco R-I-B fragment do not contain this viral protein. Other experiments have located the structural gene of the signle-strand specific DNA-binding protein in the Eco-R-I-B DNA fragment, indicating that when this gene is present in a transformed cell, it is expressed.

Adenoviridae↗