Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0033687 (proteinuria)
 24,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of the histochemical protein tracer, horseradish peroxidase, was studied in proximal tubules of rats with Heymann nephritis. Peroxidase reabsorption was substantially reduced in stage 2 of Heymann nephritis, a period during which the brush border of proximal tubules is severely damaged by specific antibodies. Impairment of the reabsorption function could not be attributed either to proteinuria or disturbances of proximal tubule metabolism and appeared to result from loss of microvilli. Recovery of brush border membrane morphology in stage 4 of Heymann nephritis was not accompanied by recovery of the normal capacity to reabsorb peroxidase. Functional deficits resulting from immunologic injury to proximal tubules in Heymann nephritis may persist despite waning of the anti-brush border antibody response and regeneration of the brush border of proximal tubule cells.
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PMID:Reabsorption of horseradish peroxidase by proximal tubules in rats with Heymann nephritis. 348 9

The glomerular tip nephropathy is a cause of the nephrotic syndrome and has distinct pathological features. Glomerular tufts appear normal on light microscopy except for a segmental lesion invariably present in all glomeruli at the origin of the proximal tubule. Data on twenty adults whose renal biopsies demonstrated this lesion and who were followed for a mean of 7.4 years are analyzed. Eighteen patients were treated with steroids; ten of these had complete remission of proteinuria and seven a significant reduction of their proteinuria. Ten patients had moderately impaired renal function (serum creatinine greater than 120 mumol/l) at presentation, eight received steroids and achieved a reduction in serum creatinine. The prognosis was good, with no patient developing chronic renal failure requiring dialysis.
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PMID:The glomerular tip lesion: a steroid responsive nephrotic syndrome. 359 37

The intralysosomal proteinases, cathepsins B and L, were measured in microdissected segments of rat nephrons following a single injection of puromycin aminonucleoside (PAN). Z-Phenylalanyl-arginine-7-amido-4-methylcoumarin served as substrate. Enzyme activities, proteinuria, creatinine clearance and renal morphology were determined at specific time intervals following induction of PAN nephrosis. During the first three days following PAN injection, enzyme activities in S2 and S3 segments, protein excretion, creatinine clearance and appearance of the renal parenchyma resembled control animals. The enzyme activity in S1 segments was slightly decreased, but returned to control levels at day six after injection. Days four through eight post-PAN injection were characterized by a dramatic increase in protein excretion and an increase in cathepsin B and L activity in S2 and S3 segments of the proximal tubule. During days 9 through 15 enzyme activity decreased significantly in S2 segments despite continued proteinuria. Overt necrosis and cell injury were seen in the proximal tubule and probably account for the decrease in proteolytic activity. After day 15 following PAN injection, the level of proteinuria decreased, restoration of cathepsin activities occurred and a histopathologic picture of healing was present. The data suggest a positive relationship exists between stimulation of cathepsin B and L activity in S2 and S3 segments of the proximal tubule and increased protein filtration in PAN nephrosis. The increased enzyme activity reflects enhancement of the proteolytic capacity of the lysosomal system that is necessary for increased protein catabolism.
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PMID:Cathepsin B and L in nephron segments of rats with puromycin aminonucleoside nephrosis. 366 94

Sex-dependent protein handling in the rat renal tubular system was studied both qualitatively and quantitatively using the method of direct fluorescent protein tracing. The protein tracer, fluorescent ovalbumin, was synthesized by conjugating hen ovalbumin with fluorescein isothiocyanate (FITC), and the fluorescence characteristics of fluoresceinthiocarbamyl (FTC)-ovalbumin conjugates with different degrees of labelling were studied. Heavily labelled tracer was intravenously injected into male and female rats, and both kidneys were perfused; the right kidney was then homogenized and used for quantitative fluorometric measurements, while the left kidney was perfusion fixed and prepared for fluorescence microscopy. The tubular reabsorption of fluorescent ovalbumin was studied 4 min and 10 min after the injection of different doses (1.4, 7.0 and 14.0 mg/kg body weight) of the tracer, and the tubular catabolism was investigated in animals killed 60 and 120 min after the injection. Fluorescence microscopy demonstrated that, in both sexes and regardless of the dose administered and the time after injection, specifically fluorescent protein or its degradation products was only present in the epithelial cells of the proximal tubule. With regard to sex-dependent differences in protein handling, fluorometry indicated that at 4 min (7.0 mg) and at 10 min (all doses) after injection, female animals had reabsorbed more fluorescent protein than males. With regard to the catabolic phase, both the fluorescence microscopy and the fluorometric results showed that the female rats had degraded the fluorescent tracer at a significantly higher rate than males. The results are discussed in connection with sex-dependent proteinuria in rats.
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PMID:Sex-related differences in the handling of fluorescent ovalbumin by the proximal tubule of the rat kidney. 372 12

The progression of changes in rabbit kidney function following dosing with the nephrotoxin S-(1,2-dichlorovinyl)-L-cysteine (DCVC, 20-50 mg/kg) was determined. Proteinuria was observed 0.5-1 hr after administration of DCVC at doses of 20-50 mg/kg. Blood urea nitrogen levels, glomerular filtration rates, urinary glucose excretion, and urine volume were also altered following DCVC dosing; however, these parameters were less sensitive than proteinuria as markers of early renal dysfunction. None of these latter four indicators were affected by low DCVC doses, nor were they altered by high DCVC doses until 1.5-2.5 hr after dosing. Dose-dependent morphological changes to kidney structure were also observed 5 hr after DCVC administration. Low doses caused damage restricted to brush border membranes in the pars recta, while higher doses produced a necrotic lesion encompassing all regions of the proximal tubule. This study indicates that DCVC can cause rapid renal dysfunctional changes which are first detected by elevated urinary protein excretion.
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PMID:Early biological indicators of S-(1,2-dichlorovinyl)-L-cysteine nephrotoxicity in the rabbit. 381 16

Alterations in kidney function were assessed early in the course of Heymann nephritis that was induced in rats by immunization with Fx1A, an extract prepared from rat kidney cortex. Whole kidney and single nephron function were evaluated by clearance and micropuncture techniques. Kidney function was studied in stage 1 of Heymann nephritis, before the onset of proteinuria, and in stage 2, when antibodies are deposited along the brush border of proximal tubules. Although overall kidney function was similar in rats in stage 1 and normal controls, glucose reabsorption was somewhat depressed in the first part of the proximal convoluted tubule in stage 1. Both whole kidney and single nephron glomerular filtration rates were depressed in stage 2. Proteinuria in stage 2 was characterized by an increased albumin sieving coefficient, which resulted in an elevated excretion of albumin. Furthermore, several proximal tubule functions (glucose and fluid reabsorption and PAH extraction) were substantially depressed in stage 2. These findings demonstrate that immunological injury to the proximal tubules in stage 2 of Heymann nephritis produces a significant impairment of proximal function.
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PMID:Pathophysiology of the kidney in rats with Heymann nephritis. 387 41

Deposits of C3 but not of C1q and C4 were detected on the proximal tubules of kidneys from nephrotic patients with non-selective proteinuria. The incidence of tubular C3 deposits was significantly higher in patients with membranous glomerulonephritis, focal glomerulosclerosis, membrano-proliferative glomerulonephritis and non-selective proteinuria than in patients with minimal change disease, nephrotic syndrome and selective proteinuria or in patients with glomerular disease, but without nephrotic syndrome. The occurrence of tubular C3 deposits was positively correlated with the amount of urinary C3 excretion. In vitro studies showed that the human normal kidney as well as pathologic specimens negative for in vivo tubular C3 deposits were able to bind C3 on the brush border of proximal tubules when incubated with fresh heterologous serum. In contrast, in patients with non-selective proteinuria and in vivo tubular C3 deposits, the binding of heterologous C3 to the brush border of proximal tubules was markedly reduced. The positive correlation between the occurrence of tubular C3 deposits and the urinary complement excretion, together with the detection of the C3 breakdown products in the urines further supported the hypothesis that complement components, once filtrated through the glomerular barrier, might be activated by the brush border of the proximal tubule.
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PMID:In vivo localization of C3 on the brush border of proximal tubules of kidneys from nephrotic patients. 388 30

A low dose of methyl mercuric chloride fed to female rats for 12 weeks caused extrusion of numerous cytoplasmic masses from kidney proximal tubule cells of the pars recta segment. These masses were characterized ultrastructurally by the presence of a smooth endoplasmic reticulum aggregate. The in vivo metabolism of methyl mercury to inorganic mercury may produce this effect and account for the proteinuria observed in persons occupationally exposed to organic mercury compounds.
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PMID:Ultrastructural evidence for nephropathy induced by long-term exposure tosmall amounts of methyl mercury. 505 18

Antibiotics are the principal cause of drug-associated nephropathy. They are responsible for acute interstitial nephropathy (AIN) or acute tubulo-interstitial nephropathy (ATIN) due to two different pathophysiologic mechanisms: a drug-induced immunologic process and direct action due to drug accumulation. 1) Ain of immunologic origin. These are rare and are induced either by beta-lactamines or by rifampicin. Among the beta-lactamines, methicillin is the most often responsible, while penicillin and ampicillin are less often, and only rarely are carbenicillin, oxacillin, nafcillin, cephalothin and cephalexin. Macroscopic hematuria occurring 10 to 15 days after initiation of treatment usually reveals the renal involvement. It is associated with or preceded by fever, skin eruption and blood eosinophilia. Renal insufficiency (RI) is not severe and rarely requires hemodialysis (HD). The course is usually favorable. Rifampicin-induced AIN is observed in two circumstances, either during intermittent treatment or when previous treatment is resumed. Macroscopic hematuria is rare and RI often severe. Anti-rifampicin anti-bodies are usually found. 2) ATIN due to direct toxicity. Several classes of antibiotics may be responsible: cephalosporins, polymyxins or cyclins, but it is usually observed with aminoglycosides (AG). The incidence of renal involvement due to the latter group is estimated to be 4 to 10%. Nephrotoxicity is initially reflected by polyuria, tubular proteinuria and increased enzymuria, followed by cylindruria and reduced glomerular filtration. HD is rarely required. The proximal tubule is predominantly affected; pathological findings are disappearance of the brush border and tubular necrosis. Electronic microscopy shows lysosomal alterations with numerous myelinic bodies. Tubular regeneration occurs within 15 to 30 days.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Antibiotic nephrotoxicity. 610 Jan 74

The localization of aminopeptidase M (APM), dipeptidyl peptidase I (DAP I), II (DAP II) and IV (DAP IV) in the renal section was investigated histochemically, and their activities were determined fluorometrically in renal homogenate of normal, castrated and testosteron treated male rats.--After castration the activities of the lysosomal DAP II (pars convoluta of the proximal tubule), DAP I (distal and proximal tubule) and of the mainly membrane-bound DAP IV (glomeruli, brush border of the proximal tubule) increase in comparison to normal males, whereas the activities of the brush border-bound APM decrease. After testosteron treatment of castrated animals (0.1, 0.5 and 1.0 mg testosterone proprionate/100 g BW and day; 5-day treatment) the activities of DAP I, II and IV decrease again, so that after treatment with 0.1 mg testosterone proprionate, the activities of DAP I and II approach those in normal males.--The additionally determined urinary protein excretion shows that there is a significant decrease in proteinuria after castration, whereas testosterone treatment of castrated animals is accompanied by an increase of proteinuria.--Our results would suggest that the protein catabolism in the proximal tubule and the proteinuria are interrelated, and that testosterone influences (decreases) the protein catabolism in the proximal tubule. This means that high activities of lysosomal proteinases in the proximal tubule (castrates) are accompanied by a low proteinuria, and low activities of those proteinases (testosterone treated castrated or normal males) by a high proteinuria.
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PMID:[Peptidases in the kidney of male rats following castration and testosterone substitution]. 614 13


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