Chemoprevention of human actinic keratoses by topical DL-alpha-tocopherol.

Prior research shows that topical application of free, nonfatty acid-conjugated vitamin E (DL-alpha-tocopherol) prevents skin cancer in mice, as well as immunosuppression induced by UVB radiation. This study investigated the chemopreventive potential of DL-alpha-tocopherol in humans through monitoring surrogate end point biomarkers in sun-damaged skin. Contralateral arms of healthy human volunteers with actinic keratoses (AK) were randomly assigned to receive either 12.

Dichlorido(4,5-diaza-fluoren-9-one-κN,N')palladium(II).

The structure of the title compound, [PdCl(2)(C(11)H(6)N(2)O)], shows a nearly square-planar geometry for the Pd(II) atom within a Cl(2)N(2) donor set.

Effects of repeated green tea catechin administration on human cytochrome P450 activity.

Purpose: Preclinical studies suggested that green tea or green tea catechins can modulate the activities of drug-metabolizing enzymes. We conducted this clinical study to determine the effect of repeated green tea catechin administration on human cytochrome P450 (CYP) enzyme activities.

Methods: Forty-two healthy volunteers underwent a 4-week washout period by refraining from tea or tea-related products.

Reproducibility and expression of skin biomarkers in sun-damaged skin and actinic keratoses.

Objectives: To explore p53 and proliferating cell nuclear antigen (PCNA) expression and polyamine content as biomarkers in skin cancer chemoprevention trials, we evaluated their expression in early stages of UV-induced squamous cell tumorigenesis.

Methods: Biopsies were collected from three groups: 78 subjects with sun damage on forearms, 33 with actinic keratosis (AK) on forearms, and 32 with previous squamous cell carcinoma. Participants with sun damage were randomized to sunscreen or no sunscreen.

Quantification of a cytochrome P450 3A4 substrate, buspirone, in human plasma by liquid chromatography-tandem mass spectrometry.

A sensitive HPLC-tandem mass spectrometry method was developed for determination of buspirone levels in human plasma. After solid phase extraction and reversed phase HPLC separation, detection of buspirone and the internal standard (prazosin) was performed using eletrospray ionization and selected reaction monitoring in the positive ion mode. Linear calibration curves were established over a concentration range of 0.

Circulating endogenous retinoic acid concentrations among participants enrolled in a randomized placebo-controlled clinical trial of retinyl palmitate.

Retinoids have been studied extensively for their chemopreventive properties. The biological activity of retinoids is acquired through their conversion to retinoic acid (RA). Characterization of endogenous circulating RA concentrations after supplementation with vitamin A over longer time periods has not been done previously.

Expression and regulation of glutathione S-transferase P1-1 in cultured human epidermal cells.

Six families of glutathione S-transferases (GSTs), which play an important role in cellular detoxification, are identified in human cells. We report that human keratinocytes and melanocytes express significant levels of GST activity, for which GSTP1-1 is mainly responsible. But, in contrast to previous reports that GSTP1-1 level increases in skin tumor tissues, GSTP1-1 expression does not increase in transformed keratinocytes and melanocytes in culture.