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Biomedical subjects

D K Chalker

Publications and source records attributed to D K Chalker.

31 records · Page 2Linked to original sources

Serologic survey for markers of hepatitis B infection in dermatologists.

A serologic survey for markers of hepatitis B virus (HBV) infection was conducted in 593 dermatologists. Serologic evidence for previous infection was found in 15.4%, indicating that dermatologists are an at-risk population comparable to many other specialties of medicine. Dermatologists with a history of blood transfusion, tattoo, and homosexuality had an increased prevalence of serologic markers for HBV. The type of practice, extent of surgery, and glove-wearing practices did not correlate with HBV serologic markers.

Adult↗

A double-blind study of the effectiveness of a 3% erythromycin and 5% benzoyl peroxide combination in the treatment of acne vulgaris.

One hundred sixty-five subjects completed a 10-week, double-blind controlled study comparing the following: (1) a combination of 3% erythromycin and 5% benzoyl peroxide in a gel, (2) 5% benzoyl peroxide gel, (3) 3% erythromycin gel, and (4) the gel vehicle. The benzoyl peroxide gel and the erythromycin gel were superior to the control gel; however, the combination product was more effective than any of the others. This was true for both pustular and papular lesions, but the most dramatic effect was on combined inflammatory lesions, i.e., papules and pustules.

Acne Vulgaris↗

Circadian rhythms and differences in epidermal and in dermal cel proliferation in uninvolved and involved psoriatic skin in vivo.

Using in vivo DNA labeling procedures, the present study makes a detailed comparative analysis of circadian rhythms in labeling indexes (Is), in mitotic indexes (Im), and in Is/Im ratios in uninvolved and in involved psoriatic epidermis in vivo (12 patients, studied at 6-hr intervals over a 24-hr period). We also provide comparable data on the rates of epidermal DNA synthesis and on the proliferative activity of dermal infiltrate cells. There are no circadian-diurnal variations in epidermal or in dermal infiltrate cell proliferation in either inactive (uninvolved) or in active (involved) lesions of psoriatic skin. The rates of epidermal DNA synthesis were lower at 9 AM and 3 PM; higher at 9 PM and 3 AM in both uninvolved and involved epidermis. The following cell kinetic information was derived from 78 biopsy samples-from epidermal mitotic and labeled nuclei counts in approximately 100 mm unit lengths of epidermis per biopsy. DNA labeling indexes, 6.1 vs. 21.2%; mitotic indexes, 0.13 vs. 0.43%; and Is/Im ratios, 152/1 vs 70/1 in uninvolved vs. involved psoriatic epidermis in vivo. There was an overall 20% decrease in the rate of cycling epidermal cell DNA synthesis involved epidermis; and 5-fold increase in the overall proliferative activity of dermal infiltrate cells in involved psoriatic skin. These results are discussed in relation to the clinical use of circadian rhythms for the "chronotherapy" of proliferative diseases in man, in relation to cell cycle aspects of psoriasis and psoriatic epidermal responses to therapy, and in relation to cell proliferation in human epidermis in vivo.

Adult↗

Topical erythromycin with zinc in acne. A double-blind controlled study.

This double-blind controlled study investigated the effectiveness of 4% topical erythromycin liquid with 1.2% zinc acetate and 4% topical erythromycin gel with 1.2% zinc octoate applied twice daily in comparison with 250 mg of oral tetracycline twice daily and placebo. One hundred forty-nine patients began and one hundred forty-one completed the study. Three judges recorded acne measurements of severity grade, papule counts, pustule counts, comedo grades, and comedo counts without mutual consultation on visits at 0, 2, 4, 6, 8, and 10 weeks. Analysis of the reduction in the acne severity grade and papule count showed that the erythromycin/zinc liquid and gel were statistically significantly better than placebo and as effective as the oral tetracycline. Analysis of comedo grades showed that at weeks 8 and 10 the 4% topical erythromycin/zinc liquid showed a reduction statistically better than placebo.

Acne Vulgaris↗

The effectiveness of topical and oral tetracycline for acne.

A group of 135 college students with acne was evaluated in a 12-week, double-blind study comparing placebo, oral tetracycline 0.5 gm daily, and a new topical tetracycline preparation. The topical tetracycline preparation containing n-decyl methyl sulfoxide to enhance penetration, produced statistically significant improvement of acne as compared to placebo after 7, 10, and 12 weeks of treatment. Oral tetracycline, 0.5 gm daily, was statistically significantly more effective for acne than placebo after 4, 7, 10, and 12 weeks of therapy. The placebo group also had marked improvement which may have been related to sun exposure. Emotional stress produced by final examinations had no apparent effect on the patients given placebo, oral, or topical tetracycline. Side effects of the topical tetracycline included a slight yellowish discoloration of the skin in 25% of the subjects and transient stinging or tingling sensation after application in 36%.

Acne Vulgaris↗

Corticosteroid-induced cutaneous atrophy and telangiectasia. Experimental production associated with weight loss in rats.

A bioassay for the evaluation of certain adverse effects of various corticosteroids was performed. Twenty-eight daily topical applications of corticosteroids to young rats produced reduction in body-weight gain, atrophy of the skin as determined by double skin-fold thickness micrometer measurement, and mild to severe telangiectasia. This animal model demonstrates corticosteroid-induced skin atrophy and telangiectasia and the correlation of the degree of atrophy and telangiectasia to body-weight change. Nine corticosteroids were evaluated by this method and are listed in terms of increasing severity of side-effects as follows: 1.0% hydrocortisone cream, 0.1% betamethasone valerate cream, 0.025% betamethasone benzoate cream, 0.05% flurandrenolide cream, 0.05% fluocinonide cream, 0.1% dexamethasone cream, and 0.03% flumethasone pivalate cream. Triamcinolone acetonide cream, 0.5%, and 0.2% fluocinolone acetonide cream resulted in death of the animals prior to completion of 28 days of topical application.

Administration, Topical↗