Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Distal urinary acidification abnormalities may arise from transepithelial voltage defects, permeability defects, or proton-secretory defects, but tests to determine the cellular mechanisms underlying secretory abnormalities have not previously been reported. A patient with Sjogren's syndrome and distal renal tubular acidosis due to a secretory defect is described, whose kidney biopsy was examined by fluorescent immunocytochemistry with an antibody to the M(r) 31,000 subunit of the mammalian kidney vacuolar H(+)-ATPase and was compared with normal human kidney. Staining with the anti-H(+)-ATPase antibody in normal human kidney was detected in the brush border microvilli and subvillar invaginations of the proximal tubule and in intercalated cells in the collecting duct. A biopsy sample from the patient was devoid of any anti-H+-ATPase staining in the intercalated cells. Staining was also absent from the proximal tubule brush border microvilli but was present in the subvillar invaginations. Although autoantibodies to normal human kidney membrane proteins were detected in the serum by immunoblot analysis, no immunocytochemical evidence for anti-intercalated cell autoantibodies was observed in the patient's serum. This report demonstrates that the basis for the proton secretory defect in some patients with distal renal tubular acidosis is likely the absence of H(+)-ATPase in the intercalated cells. It also illustrates the potential diagnostic utility of anti-H(+)-ATPase antibodies in the classification of distal renal tubular acidoses.
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PMID:Absence of H(+)-ATPase in cortical collecting tubules of a patient with Sjogren's syndrome and distal renal tubular acidosis. 139 25

Kidney transplant rejection may be accompanied by defective urinary acidification. Its pathogenesis is unknown. There are shared histologic features between kidney transplant rejection and the distal renal tubular acidosis (RTA) of Sjogren syndrome, which led us to hypothesize that deficient collecting duct H+ adenosine triphosphatase (ATPase) expression--which is lacking in the RTA of Sjogren syndrome - may cause the RTA of kidney transplant rejection. Six kidney transplant recipients with biopsy evidence for rejection and two control subjects were studied physiologically and by immunohistochemistry. We found defective urinary acidification in all 6 kidney transplant patients. Ammonium excretion was diminished in relation to the degree of azotemia. There was an abnormal response to furosemide in all 6, suggesting distal tubular dysfunction. Distal H+ ATPase staining was reduced in relation to the degree of azotemia, although it was not totally absent even in the worst case. This was paralleled by the urinary PCO2 response. Both control subjects had good urine PCO2 and H+ ATPase staining and adequate urine pH response to furosemide. They had reduced urinary ammonium (NH4) concentrations in relation to modest azotemia. We conclude that kidney transplant rejection may be accompanied by defective urinary acidification, which is not primarily due to a lack of H+ ATPase. The RTA of kidney transplant rejection appears to result from defective ammonium excretion, generalized distal tubular malfunction, and--in severe cases--from a reduction in distal nephron H+ ATPase expression.
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PMID:An immunocytochemical study of H+ ATPase in kidney transplant rejection. 927 65