Studies have been made on water soluble antigens of the retina from man and some animals. In the bovine retina, immunochemical analysis reveals, apart from antigens with a broad and narrow interorganic specificity, organospecific alpha 1- and rho-globulins. Immunochemically, the bovine alpha 1-globulin is partially identical with the same protein of the human retina and completely identical to retinal antigens from cattle; rho-globulin is characterized as an interspecific antigen in man and mammals. Molecules of organospecific alpha 1-globulins from the retina of man and some animals (sheep, camel, horse, cow, pig) do not contain the determinants related to the retinal antigens from fishes, reptiles and birds. In human and mammalian retina, acid neurospecific alpha 1-glycoprotein was found which is topical of the cerebral tissue. Organospecific alpha 1-globulin of the bovine retina is located in the pigment epithelium, in the zone of outer and inner photoreceptor segments; organospecific rho-globulin is distributed in the outer synaptic layer of the retina.
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Eur J Biochem
June 1996
Department of Pharmacology and Toxicology, School of Medicine, University of Marburg, Germany.
The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NC), which is generated by nitrosation of nicotine, requires enzymatic activation by cytochrome-P450-mediated alpha-carbon hydroxylation to yield particularly powerful carcinogenic alkylating intermediates. Pyridine-N-oxidation and carbonyl reduction are detoxification pathways, the latter by providing the functional hydroxy moiety necessary for glucuronosylation and final excretion of NC. For more than a decade, the enzyme responsible for NC carbonyl reduction has awaited characterization.
View Article and Find Full Text PDFChem Res Toxicol
December 1992
Division of Chemical Carcinogenesis, American Health Foundation, Valhalla, New York 10595.
4-Ipomeanol (IPO) is an investigational chemotherapeutic drug with specific toxicity toward the lung. It is metabolically activated to reactive intermediates by cytochrome P450 enzymes present in Clara cells. 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a highly carcinogenic tobacco-specific nitrosamine with organo-specificity for the lung.
View Article and Find Full Text PDFCarcinogenesis
October 1989
Institut National de la Santé et de la Recherche Médical, U 128, Montpellier, France.
An altered pattern of cytochrome P-450-dependent microsomal steroid metabolism was identified in female mouse liver tumors induced by 5,9-dimethyldibenzo[c,g]carbazole, a potent organo-specific liver carcinogen. These tumor tissues were compared to extratumoral liver parenchyme, to normal, fetal and neonatal livers and to spontaneous liver tumors, the frequency of which is very low in the highly hybridized mouse strain (XVIInc/Z) used for liver tumorigenesis. Cytochrome P-450-dependent steroid hydroxylase activities were measured by the identification and quantification of four monohydroxyprogesterone and eight monohydroxytestosterone metabolites.
View Article and Find Full Text PDFArch Surg
February 1989
Department of Surgery, Dartmouth Medical School, Hanover, NH 03755.
The organospecific, 1,2-dimethylhydrazine-induced murine tumor model was used to test the effects on tumor formation of the following dietary supplements: (1) ascorbic acid, 7% per weight; (2) alpha tocopherol, 1% per weight; (3) beta carotene, 1% per weight; and (4) canthazanthin, 1% per weight. Following a four-week dietary acclimation, a 16-week 1,2-dimethylhydrazine induction, and a four-week hiatus, the animals were killed, underwent autopsies, and tumor formation was recorded. The antioxidant supplements of ascorbic acid and alpha tocopherol resulted in a significant decrease in tumor formation when compared with control groups.
View Article and Find Full Text PDFVopr Onkol
December 1988
An immunochemical study of normal prostatic tissue, adenoma and cancer identified the following five antigens: alpha 2-ferroprotein, tissue gamma-esterase, lactoferrin, acidic phosphatase and prostatic beta-globulin. The two latter proteins proved organo-specific prostatic antigens. Levels of all the proteins were measured in normal, adenoma and cancer tissues.
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