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Biomedical subjects

L A Drake

Publications and source records attributed to L A Drake.

At least 19 recordsLinked to original sources
PubMed1995

Polarized light photography in the evaluation of photoaging.

BACKGROUND: The clinical characteristics of photodamaged skin, such as coarse and fine wrinkling, sallowness, hyperpigmentation, tactile roughness, laxity, and erythema, are not accurately evaluable from photographic records. OBJECTIVE: The purpose of this study was to develop accurate and reproducible photographic techniques that generate an evaluable record of the characteristics of photodamaged skin. METHODS: The method used involved illumination and photography through polarizing filters (polarized light photography). RESULTS: Polarized light photography generates images that selectively enhance either the surface features or the subsurface features of the skin, providing an accurate and evaluable record for evaluation of photodamaged skin. CONCLUSION: Polarized light photography, when coupled with precise framing and mapping, yields an accurate and evaluable record of photodamaged skin.

Humans↗
PubMed1995

A single parameter, oxygenated hemoglobin, can be used to quantify experimental irritant-induced inflammation.

To quantify the dose-response relation of irritant-induced erythema, we examined inflammation in human skin after application of an irritant, using perpendicular polarized photography and diffuse reflectance spectroscopy as compared to clinical visual scoring. The ventral forearms of 11 healthy subjects were patch-tested for 24 h under occlusion in finn chambers with five concentrations of the irritant sodium lauryl sulfate. The tested sites and three control sites were evaluated clinically for erythema at 24, 48, and 72 h after occlusion, photographed using standard and perpendicular polarized photography, and measured by diffuse reflectance spectroscopy. All photographs were evaluated for erythema by three investigators. Diffuse reflectance spectra were analyzed, and changes in apparent oxyhemoglobin and deoxyhemoglobin concentrations were estimated. Clinical and photographic assessments of erythema yielded similar linear dose-response relations. A linear dose-response relation, with no minimum threshold, also was obtained for changes in the apparent oxyhemoglobin concentration with increasing irritant dose, whereas the apparent deoxyhemoglobin concentrations were unchanged with increasing dose. These results show that diffuse reflectance spectroscopy permits the characterization of irritant-induced inflammation in terms of a single parameter, the apparent concentration of oxyhemoglobin, and that irritant-induced inflammation primarily involves the capillaries and the superficial arterial plexus.

Dose-Response Relationship, Drug↗
PubMed1995

The antipruritic effect of 5% doxepin cream in patients with eczematous dermatitis. Doxepin Study Group.

BACKGROUND AND DESIGN: Eczematous dermatitis is commonly characterized by intense pruritus. Current treatment modalities for this condition, regardless of its cause, are primarily directed at blunting the cutaneous inflammatory response and thereby providing relief of pruritus. To expand on our previous findings in atopic dermatitis, the present multicenter double-blind trial was conducted to evaluate the safety and antipruritic efficacy of 5% doxepin hydrochloride cream in patients with lichen simplex chronicus (n = 136), nummular eczema (n = 87), or contact dermatitis (n = 86). A total of 309 patients with moderate to severe pruritus were randomly assigned to apply either doxepin cream (n = 154) or vehicle cream (n = 155) to eczematous areas four times per day for a period of 7 days. Efficacy was assessed using a pruritus severity rating scale, a Physician's Global Evaluation for pruritus relief, and a Visual Analogue Scale for pruritus relief. RESULTS: Twenty-four hours after initiation of treatment, and continuing throughout the remainder of the study, patients treated with doxepin cream experienced significantly greater pruritus relief than did vehicle-treated patients as determined by all efficacy parameters (P < .002). Sixty percent of doxepin-treated patients experienced pruritus relief within 24 hours. The response rate increased to 84% by conclusion of the study. As judged by significant changes (P < or = .05) occurring in at least one assessment of efficacy, doxepin cream provided pruritus relief in all forms of eczematous dermatitis that were examined. The study medication was well tolerated. The two most common adverse effects, stinging at the site of application and drowsiness, were usually transient and mild to moderate in severity. CONCLUSION: Topical application of doxepin provides significant antipruritic activity with a favorable safety profile, suggesting a role for doxepin cream in the symptomatic treatment of pruritus associated with eczematous dermatitis.

Administration, Cutaneous↗
PubMed1992

Ocular and periocular infections.

The eye is an important site for infectious disease because an incorrect diagnosis can cause loss of vision or loss of life. An approach to accurate diagnosis, intervention, and therapy is outlined.

Blepharitis↗
PubMed1987

Activity of DNA and RNA polymerases in resurfacing rabbit corneal epithelium.

Activity of RNA polymerases I, II and III (distinguished using alpha-amanitin) and activity of DNA polymerases alpha and beta (distinguished using N-ethylmaleimide) were assayed for varying intervals and at varying substrate (UTP or dTTP) concentrations in the purified nuclear fraction from corneal epithelium of carbamylcholine-treated and control eyes of rabbits with resurfacing acid burn defects. Incorporation was linear with time for all enzymes up to 30 min. In 10 min assays at varying substrate concentrations, all polymerases from carbamylcholine-treated eyes had significantly elevated Vmax compared to corresponding control enzymes. The drug also increased apparent affinity of RNA polymerase II for UTP and apparent affinity of DNA polymerases alpha and beta for dTTP. Results are discussed in relation to potential mechanisms by which effects of carbamylcholine on polymerase activity may be mediated.

Animals↗