Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously identified transcripts encoding a G protein-coupled, extracellular calcium/polyvalent cation-sensing receptor, RaKCaR, in rat kidney (D. Riccardi, J. Park, W.-S. Lee, G. Gamba, E. M. Brown, and S. C. Hebert. Proc. Natl. Acad. Sci. USA 92:131-135, 1994), which was proposed to provide the mechanism for modulating a variety of renal functions in response to changes in extracellular Ca2+ (E. M. Brown. In: Handbook of Physiology. Bethesda, MD: Am. Physiol. Soc., 1992, sect. 8, vol. 2, chapt. 39, p. 1841-1916; and S. C. Hebert. Kidney Int. 50: 2129-2139, 1996). Here, we examine the cellular and regional distribution of receptor protein by immunofluorescence microscopy using a polyclonal antibody raised against a 22 amino acid region of the NH2 terminus of the receptor. The most intense fluorescence was seen at the basolateral border of cortical thick ascending limb cells. Basolateral staining for the receptor was also detected in medullary thick ascending limbs, in macula densa cells identified by costaining with antibody to brain nitric oxide synthase, NOS-B1, and in distal convoluted tubule cells distinguished by costaining for the apical thiazide-sensitive Na(+)-Cl- cotransporter. Apical anti-RaKCaR staining was detected at the base of the brush border of proximal tubules with decreasing intensity from S1 to S3 segments. In cortical collecting ducts, anti-RaKCaR staining was detected in some, but not all, type A intercalated cells identified by costaining with anti-H(+)-ATPase and anti-AE1 Cl-/HCO3- exchanger antibodies. The present study demonstrates that RaKCaR protein is expressed in many different nephron segments and that the polarity of receptor expression varies with cell type along the nephron. These results suggest potential roles for the extracellular Ca2+/ polyvalent cation-sensing receptor in responding to both circulating and urinary concentrations of divalent minerals and potentially other polyvalent cations (e.g., aminoglycoside antibiotics) to modulate nephron function.
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PMID:Localization of the extracellular Ca2+/polyvalent cation-sensing protein in rat kidney. 953 Feb 79

Alternative models using fish species have been tested in liver toxicity and carcinogenesis bioassays. Similar models have not been developed for skin. The brown bullhead (Ameiurus nebulosus) has shown potential as a model for skin carcinogenesis studies due to its sensitivity to environmental chemical pollutants. The present study is an initial morphologic and biochemical characterization of the normal and neoplastic brown bullhead skin to assess its suitability as a model of skin carcinogenesis. Brown bullhead were removed from Back River in the Chesapeake Bay region, an area historically polluted with heavy metals and polycyclic aromatic hydrocarbons. Histology, histochemistry, and electron microscopy were used to stage the morphologic development and progression of neoplasia in skin. The distribution of keratin, a family of structural proteins with altered expression in mammalian tumorigenesis, was analyzed with one and two dimensional gel electrophoresis and nitrocellulose blots of extracts from normal skin. Keratin expression in skin and other organs was also assessed with immunohistochemistry using AE1, AE3, and PCK 26 antibodies, and the proliferation index in skin and neoplasms with PCNA antibody. Skin lesions appeared to progress from hyperplasia through carcinoma, and the proliferation index was increased in papilloma. Also in papilloma, intercellular interdigitations appeared increased and desmosomes decreased which may in future studies correlate with changes in expression of other molecular markers of neoplastic progression. Both Type I and Type II keratin subfamilies were detected in skin using gel electrophoresis with the complimentary keratin blot-binding assay. For further development of the brown bullhead model, future studies can compare and relate these baseline data to alterations in expression of keratin and other markers in fish neoplasms and to molecular events which occur in man.
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PMID:Brown bullhead (Ameiurus nebulosus) skin carcinogenesis. 1093 Jan 21