References: Hair growth and hair loss
J Invest Dermatol. 1997 Mar;108(3):324-9.
Keratin 17 gene expression during the murine hair cycle.
Panteleyev AA, Paus R, Wanner R, Nurnberg W, Eichmuller S, Thiel R, Zhang J, Henz BM, Rosenbach T.
Severtsov Institute of Ecology and Evolution, Russian Academy of Science, Moscow.
Keratin 17 (K17) expression is currently considered to be associated with hyperplastic or malignant growth of epithelial cells. The functions of this keratin in normal skin physiology and the regulation of its gene expression, however, are still unclear. As one possible approach to further explore K17 functions, we have studied the differential patterns of mouse K17 (MK17) transcription during the murine hair cycle by means of in situ hybridization, using a digoxigenin-labeled riboprobe. Cycling hair follicles in the skin of C57BL/6 mice were found to be the only skin structures expressing MK17 under physiologic conditions. MK17 transcripts were constantly observed throughout all hair cycle stages in the suprainfundibular outer root sheath (ORS). The MK17 expression was also evident in the isthmus part of the ORS, where it was expressed weakly and was spatially restricted during telogen, with an increase in early anagen and stable expression during mid- and late anagen, localizing to the zone of so-called trichilemmal keratinization. In addition, in early anagen, a group of epithelial cells in or next to the bulge region stained weakly for MK17. With progressing anagen development, MK17 expression in this region increased and was consistently localized to keratinocytes at the advancing front of the emerging epithelial hair bulb. In mid- and late anagen, this zone of MK17 expression spread along the proximal ORS, with a maximal level of expression in the innermost cell layer of the ORS. Overall, these findings provide data on the MK17 expression profile of normal murine skin and demonstrate hair-cycle-dependent regulation of MK17 expression.
online pharmacy ref. source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9036933&dopt=Abstract
Biochem Pharmacol. 1997 Jan 24;53(2):215-21.
Characterization of recombinant human liver dehydroepiandrosterone sulfotransferase with minoxidil as the substrate.
Kudlacek PE, Clemens DL, Halgard CM, Anderson RJ.
Section of Endocrinology, Diabetes and Metabolism, VAMC, Omaha, NE 68105, USA.
Biotransformation of xenobiotics and hormones through sulfate conjugation is an important metabolic pathway in humans. The activation of minoxidil, an antihypertensive agent and hair growth stimulator, by sulfation (sulfonation) is carried out by more than one sulfotransferase. Initially only the thermostable form of phenol sulfotransferase was thought to catalyze minoxidil sulfation. We document in this report the new finding that human liver dehydroepiandrosterone sulfotransferase (DHEAST), an hydroxysteroid sulfotransferase distinct from phenol sulfotransferases, also catalyzes the reaction. To characterize more precisely the activity of DHEA ST toward minoxidil, we used COS-1 cells to express DHEA ST from a human liver cDNA clone. The apparent Km values for minoxidil and [35S]3'-phosphoadenosine-5'-phosphosulfate were 3.9 mM and 0.13 microM, respectively. The 50% inactivation temperature of the COS-expressed enzyme was 42 degrees, and the IC50 value for 2,6-dichloro-4-nitrophenol was 1.4 x 10(-4) M. Both the thermal stability behavior and response to DCNP were similar when the cDNA encoded DHEA ST was assayed with DHEA or minoxidil as a substrate. NaCl led to a greater activation of the cDNA expressed DHEA ST when assayed with DHEA (2.5-fold) than when the same preparation was assayed with minoxidil (1.4-fold). These data indicate that DHEA ST catalyzes the sulfate conjugation of minoxidil: DHEA ST activity present in the human gut and liver would be expected to add to the overall sulfate conjugation of orally administered minoxidil. Thus, DHEA ST activity must be considered when determining the human tissue sulfotransferase contribution to minoxidil sulfation.
online pharmacy ref. source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9037254&dopt=Abstract
Forensic Sci Int. 1997 Jan 17;84(1-3):17-24.
Experience with hair testing in the clinical biochemistry laboratory of Ca' Granda Niguarda Hospital, Milan, Italy.
Cassani M, Da Re N, Giuliani L, Sesana F.
Clinical Biochemistry Laboratory, Ca' Granda Niguarda Hospital, Milano, Italy.
In our laboratory, analysis of human hair for drugs of abuse detection was first performed in 1980. In the last 10 years we have processed about 2000 subjects/year ('living subjects' only). In the last 3 years we have also introduced hair analysis of cocaine: at first only in clinical applications, but for the last 2 years this analysis is now routine. Our application of hair analysis includes: clinical toxicology, medico-legal and administrative agencies. Requests come for example from several Committees for Driving Licenses, Addiction Treatment Centers and Legal Authorities. Hair samples are currently collected from the occipital area at the back of the head, which appears to show less variability in hair growth rate. At present we perform hair analysis using highly sensitive radioimmunoassay screening methods for the detection of parent drug and/or metabolites. All positive cases of cocaine and opiates abuse are confirmed by gas chromatography-mass spectrometry in electron impact or chemical ionization mode. Positive cases for opiates are also analysed using a specific morphine radioimmunoassay kit. Data show that, when the opiates/morphine ratio is higher than 6, we are dealing with consumption of codeine and/or dihydrocodeine. In our routine work last year there were 177 (263 samples) positive opiates subjects out of 2244 patients; positive cocaine subjects were 290 (362 samples) out of 2001 patients. Guidelines for hair analysis in Lombardia have been established based on the experience of our laboratory. Furthermore it will be possible to apply a unique protocol for all Committees for Driving Licenses, involving hair testing in addition to urine assay.
online pharmacy ref. source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9042706&dopt=Abstract
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