Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003129 (Anoxia)
 551 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Net Cl- absorption by Amphiuma small intestine is electrogenic but associated with the secretion of HCO3-. To define the mechanisms of Cl- entry into the enterocytes the initial rate of uptake of 36Cl into isolated segments of small intestine was measured. Luminal extracellular space was measured using [3H]inulin. Cl- influx was saturable with a Km of 5.3 mM. When the mucosal medium Cl- concentration was 20 mM influx was linear for 5 min. Cl- influx in 5 min (JiCl) was not reduced by 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid added to the serosal medium, although the Cl- current was abolished. Hence the luminal membrane was the barrier to Cl- uptake. Monovalent anions blocked Cl- influx in the order I- = SCN- = NO3- greater than Br- greater than F-. Anoxia and dinitrophenol reduced JiCl 33 and 71%, respectively. Substitution of medium Na+ with choline or N-methyl glucamine reduced JiCl 60-70%. Removal of medium K+ reduced influx 51%. After medium Na+ and K+ were both replaced influx was stimulated upon reexposure to (Na+ + K+); Na+ alone did not stimulate. JiCl was reduced 34% by furosemide. Neither amiloride nor SITS in the mucosal medium altered influx. JiCl was reduced by replacement of the HCO3- -CO2 buffer with either phosphate or N-2-hydroxyethyl-piperazine-N'-2-ethanesulfonic acid and by exposure to acetazolamide. Theophylline reduced influx 60%, whereas the Ca ionophore A23187 reduced net Cl- absorption and lowered JiCl by 17%. Norepinephrine (10(-5) M) in the serosal bathing medium stimulated Cl- influx 51%. These results indicate that Cl- influx into the intestinal mucosa occurs by a Na+- and, possibly, K+-dependent pathway. Cl- entry is under adrenergic influence.
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PMID:Characteristics of chloride ion influx in Amphiuma small intestine. 253 36

A major feature of Alzheimer's disease is the deposition of the amyloid beta peptide (Abeta) in the brain by mechanisms which remain unclear. One hypothesis suggests that oxidative stress and Abeta aggregation are interrelated processes. Protein kinase C, a major neuronal regulatory protein is activated after oxidative stress and is also altered in the Alzheimer's disease brain. Therefore, we examined the effects of Abeta(1-40) peptide on the protein kinase C cascade and cell death in primary neuronal cultures following anoxic conditions. Treatment with Abeta(1-40) for 48 h caused a significant increase in the content and activity of Ca2+ dependent and Ca2+ independent protein kinase C isoforms. By 72 h various protein kinase C isoforms were down-regulated. Following 90 min anoxia and 6 h normoxia, a decrease in protein kinase C isoforms was noticed, independent of Abeta(1-40) treatment. A combination of Abeta(1-40) and 30-min anoxia enhanced cytotoxicity as noticed by a marked loss in the mitochondrial ability to convert 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide and by enhanced 4',6-diamidino-2-phenylindole nuclear staining. Phosphorylation of two downstream protein kinase C substrates of apparent molecular mass 80 and 43 kDa, tentatively identified as the myristoyl alanine-rich C-kinase substrate (MARCKS), were gradually elevated up to 72 h upon incubation with Abeta(1-40). Anoxia followed by 30 min normoxia enhanced MARCKS phosphorylation in the membrane but not in the cytosolic fraction. In the presence of Abeta(1-40), phosphorylation of MARCKS was reduced. After 6 h normoxia, MARCKS phosphorylatability was diminished possibly because of protein kinase C down-regulation. The data suggest that a biphasic modulation of protein kinase C and MARCKS by Abeta(1-40) combined with anoxic stress may play a role in Alzheimer's disease pathology.
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PMID:Biphasic modulation of protein kinase C and enhanced cell toxicity by amyloid beta peptide and anoxia in neuronal cultures. 1115 47