Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Organic ion transport across the basolateral membrane of proximal tubules was measured by means of the tissue slice technique in each of the four different stages of Heymann nephritis. Impairment of both organic anion and cation transport was detected early in Stage 2, and became more severe in Stage 3 of Heymann nephritis. The decreased transport function was associated with extensive damage to proximal tubule cells, including loss of brush border microvilli and basal infoldings. Despite these abnormalities of structure and function, oxygen consumption of proximal tubule cells remained essentially normal. Partial recovery of organic cation transport was noted late in Heymann nephritis (Stage 4). Recovery of the cation transport function was associated with a partial restoration of brush border microvilli and basal infoldings to proximal tubule cells. However, organic anion transport remained depressed throughout the entire course of disease. Impairment of organic ion transport in rats with Heymann nephritis appeared to result from damage to basolateral membrane transport elements rather than general deterioration of the metabolic machinery of proximal tubule cells. Decreased organic cation transport appeared to be the consequence of a reduction in the number of carrier sites, a phenomenon that could have resulted from decreased membrane surface area. However, the depression of organic anion transport was associated with decreased substrate affinity of the anion carrier, indicating that qualitative, rather than quantitative changes, were primarily responsible for that defect. Specific antibody-mediated damage to the anion transport elements in basolateral membranes of proximal tubules is postulated to occur in Heymann nephritis.
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PMID:Impaired organic ion transport in proximal tubules of rats with Heymann nephritis. 387 61

The effect of cholestane-3,5alpha,6-triol (CT) on the intestinal absorption of cholesterol and oleic acid, as well as the absorption of labeled CT, was studied in lymph ductcannulated rats. Intragastric administration of 50 mg of CT in an emulsion with cholesterol-7alpha-(3)H and oleic acid-1-(14)C resulted in 50% inhibition of sterol transfer into lymph but only 8% depression of fatty acid absorption over an 8 hr period. The absorption of labeled CT into lymph was only 2-3% compared with 50% absorption of cholesterol when each was fed alone. 10% of the fed CT was recovered in the intestinal mucosa, and of this, one-half was associated with the brush border fraction. In rats fed CT 6 days prior to cholesterol and fatty acid administration, there was no effect on fatty acid absorption, while cholesterol absorption was reduced by almost 30%. When the intestinal mucosa from these animals were investigated by electron microscopy, it appeared that CT feeding resulted in numerous enlarged mitochondria and a marked increase in length of the microvilli. If animals were allowed to recover for 6 days from the CT prefeeding regime, the intestinal mucosa appeared normal, and the absorption of cholesterol approached that in controls. A possible mechanism for CT inhibition of cholesterol absorption was shown to be competition for the enzyme cholesterol esterase which esterifies cholesterol prior to entrance into the lymphatic system. CT itself is poorly esterified and poorly absorbed, but it is effective in inhibiting esterification of cholesterol in vitro.
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PMID:Inhibition of lymphatic absorption of cholesterol by cholestane-3 beta, 5 alpha, 6 beta-triol. 535 54

The purpose of this investigation was: (1) to establish a simplified radioimmunoassay (RIA) for quantitating renal tubular epithelial antigens (RTE) in urine; (2) to ascertain whether urine RTE concentrations as measured by this technique correlate with the severity of acute nephrotoxic and ischemic injury; and (3) to ascertain whether increased urinary RTE is a specific marker of renal tubular injury. A direct binding RTE RIA was established using 125I labelled anti-RTE antibody and 10% polyethylene glycol to separate bound from unbound anti-RTE 125I. This RIA is simpler than previously described RTE assay methods since: (1) double antibody separation techniques are eliminated; (2) RTE antigen purification from crude proximal tubular fragments is no longer necessary; and (3) immunoglobulin G(IgG) rather than more radiosensitive RTE is used as the radioligand. To test the utility of this assay as a marker of acute tubular injury anesthetized rats were subjected to graded nephrotoxic (HgCl2: 0--20 mg/kg) or bilateral renal ischemic (0--32 min) insults. Glomerular filtration rates (GFR) (clearance iothalamate 125I) and RTE concentrations were measured sequentially. Post-renal injury, RTE concentrations rose above control values and the degree of elevation strongly correlated with the severity of GFR depression (r = 0.72--0.81; p less than 0.02--0.05). The source of this increased urinary RTE was the proximal tubule since brush border loss was demonstrated histologically and because no RTE could be detected in serum. Rats whose GFRs were acutely depressed by inducing either volume depletion or acute experimental glomerulonephritis (nephrotoxic serum nephritis) all had normal urine RTE concentrations. These results suggest that RTE quantitation by this technique may provide a specific and early quantitative index of the severity of acute nephrotoxic and ischemic renal injury.
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PMID:Quantitating the severity of proximal tubular brush border injury by a simple direct binding radioimmunoassay. 621 75

The 'missing peptidase' hypothesis to explain the aetiology of coeliac disease has never been satisfactorily resolved and recent reports suggest that coeliac brush borders may have depressed levels of specific peptidase enzymes. It has been inferred from these studies that the subsequent brush border digestion of gliadin peptides may therefore be defective. In this present study a sensitive fluorometric assay was used to measure the hydrolysis of a peptic-tryptic digest of gliadin by both normal and coeliac brush borders. The coeliac brush borders were as efficient as the normals in hydrolysing gliadin peptides and showed no depression of any specific peptidase activity.
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PMID:Breakdown of gliadin peptides by intestinal brush borders from coeliac patients. 638 Dec 46

We report results on determinations of small intestinal brush-border enzyme activities in 22 children (aged 11 months to 14 years) with giardiasis. In particular, activities of disaccharidases (lactase, sucrase, maltase) and of alkaline phosphatase were investigated. Forty-one percent of the patients, irrespective of age, had a demonstrable depression of disaccharidase activities, usually in a combination involving two or more enzymes. A depression of intestinal alkaline phosphatase activity was present in 33% of patients, and only in those who demonstrated disaccharidase deficiencies. Mild villus atrophy was present in two mucosal specimens, whereas all others showed normal villus morphology by light microscopy. The results obtained in this study suggest that giardiasis in otherwise healthy children does not cause marked structural damage to the small bowel mucosa, as seen by the light microscope. However, some form of damage to the brush border does occur frequently, as evidenced by a depression of brush-border enzymes. This damage most likely contributes to the diarrhea and also to the carbohydrate intolerance in these patients.
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PMID:Intestinal disaccharidase and alkaline phosphatase activity in giardiasis. 642 May 34

The first site of aminoglycoside-cell interaction occurs at the plasma membrane of renal proximal tubular cells which have been shown to selectively transport and accumulate these drugs. Depression of apical membrane transport of organic base, low-molecular-weight protein, and glucose, together with loss of brush border membrane enzymes and phospholipids in the urine which results in altered phospholipid composition of this membrane, occurs early in the course of aminoglycoside administration. Less well appreciated are the alterations which occur at the basolateral membrane. These include decreased transport of organic bases, Ca2+, Na2+, and K+; increased organic acid transport; decreased activity of Na+-K+ ATPase and adenylate cyclase; decreased calcium content; and altered phospholipid composition. Many of these changes are evident within 90 min of a single injection of drug. Lysosomal dysfunction is manifested by the accumulation of phospholipids in the form of myeloid bodies consequent to the inhibition of lysosomal phospholipases by aminoglycosides. Labilization of lysosomes in vivo has been postulated to be a mechanism of cell injury. Mitochondrial dysfunction attributed to aminoglycosides includes impaired respiration, inhibition of Mg2+ binding, inhibition of Ca2+ uptake, increased permeability to monovalent cations, decreased ammoniagenesis, and decreased gluconeogenesis. However, it remains unclear how the drug gains access to mitochondria in vivo in order to initiate the functional derangements. It is evident that aminoglycosides cause multiple metabolic derangements at multiple sites within renal proximal tubular cells. At present the available evidence does not identify which, if any, of these drug effects is responsible for initiating the injury cascade. The strong possibility exists that aminoglycoside nephrotoxicity reflects the net impact of multiple minor metabolic derangements which individually are of little significance but when added together seriously compromise the cell's ability to maintain its structural and functional integrity.
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PMID:Aminoglycoside-induced functional and biochemical defects in the renal cortex. 651 73

Three strains of enterotoxigenic Escherichia coli (ETEC) (064:KSNT, K88ac; 020:KSNT, K88ac and 08:K85ab, K99) originally cultured from outbreaks of diarrhoea in piglets a few hours old, were administered orally to gnotobiotic piglets. There was a marked age-related difference in the clinical response to infection between the 3 strains although they all produced heat-stable toxin. All 3 strains produced severe clinical signs of depression, anorexia, vomiting, diarrhoea, followed by dehydration and death in one-day-old piglets. In piglets infected at 3 days of age the two K88+ ETEC caused diarrhoea and death but the K99+ ETEC induced moderate diarrhoea only. In piglets infected at 7 days of age, the 064 strain produced severe diarrhoea and death, and 020 strain caused mild diarrhoea in 3 of 6 piglets with one death while the 08 strain caused no illness. Pathological changes in the intestinal tract associated with these infections were minimal, or absent. Immunofluorescent staining with homologous hyperimmune sera demonstrated adherence of the 3 ETEC strains to the brush border of small intestinal epithelial cells. Fluorescing organisms were observed in all infected piglets irrespective of the severity of clinical signs but the degree and extent of colonisation varied with the age of the piglets and the infecting strain. This may explain the difference in clinical response between the 3 strains.
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PMID:Experimental colibacillosis in gnotobiotic piglets exposed to 3 enterotoxigenic serotypes. 676 Aug 49

Investigations by scanning electron microscopy into changes of surface morphology of small bowel mucosa in children with chronic nonspecific diarrhea are reported. The study population comprised 56 patients, ranging in age from 5 months to 7 years; 65% were between 10 and 28 months old, and 64% of the patients were boys. The major findings were: microorganisms on the mucosal surface; excessive extrusion of cell cytoplasm and of enterocytes (cell shedding); presence of excessive mucus on the mucosal surface; damage to the brush border; and partial villous atrophy. The latter lesion was found in only four patients. All these changes are considered pathologic and, for the most part, are presumed to be due to the presence of antigens, in particular, microorganisms. A depression of disaccharidase activities was encountered in 64% of the patients, but prevalence was without regard to age. Most common was a combined depression of lactase, sucrase, and maltase, as well as an isolated depression of lactase. The possibility has to be considered that enteroadherent microorganisms which are usually not considered pathogenic, and microorganisms such as Mycoplasma, may emerge as intestinal pathogens in susceptible children. It is feasible that genetic traits of the host and environmental factors facilitate adherence and colonization of the small bowel mucosa which, in turn, produces chronic diarrhea. Further studies are needed to confirm the preliminary information contained in this report.
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PMID:Chronic nonspecific diarrhea in children: investigation of the surface morphology of small bowel mucosa utilizing the scanning electron microscope. 688 51

Acute exposure of jejunal mucosa to ethanol has been reported to produce a depression of transmural glucose transport across this organ in vitro and in vivo. In an attempt to understand the mechanism of action of ethanol on intestinal transport, in the present study we have investigated the effect of ethanol on glucose uptake by purified brush-border membrane vesicles of hamster jejunum. Ethanol, in concentrations found in man after moderate drinking (1-5% w/v), was found to depress glucose uptake by the brush-border membrane in a dose-dependent and time-dependent manner. Mannose was used to measure nonspecific uptake, and we found that the ethanol-induced depression of glucose uptake was not related to an alteration of the nonspecific uptake of this sugar. The inhibition of glucose uptake of the ethanol-treated membranes completely disappeared after repeated washing of the membranes with ethanol-free buffer. Accordingly, the ethanol-induced depression of glucose uptake was not the result of irreversible damage to membrane proteins but was related to a direct effect of ethanol on the brush-border membrane. On the basis of these findings, it is concluded that a direct interference with glucose translocation across the brush border plays an important role in the ethanol-induced depression of transmural jejunal glucose absorption.
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PMID:Ethanol-induced inhibition of glucose transport across the isolated brush-border membrane of hamster jejunum. 746 Jul 5

We investigated the effects of cyclosporin A (CyA) on accelerated passive Heymann nephritis, an experimental model of membranous nephropathy, that is characterized by immune complex deposition on the glomerular basement membrane. The nephritis was induced in rats by injection of antiserum against the antigen located in the renal tubular brush border membrane and sensitization with rabbit gamma-globulin. CyA was administered p.o. at the dose of 2.5, 10 or 20 mg/kg/day for 40 days after the injection of the antiserum. The administration of CyA resulted in marked suppression of proteinuria and hypercholesterolemia in the nephritic rats. In light microscopy, nephritic control rats showed thickening of the glomerular basement membrane and spike formation in the glomeruli. CyA significantly reduced the appearance of the glomerular alteration. The production of antibody was dramatically attenuated by CyA administration. However, CyA did not decrease the number of circulating white blood cells and platelets below the normal level. In conclusion, CyA suppressed the progress of accelerated passive Heymann nephritis in a dose-dependent manner. The effect of CyA is likely attributable to the powerful depression of antibody production.
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PMID:[Effects of cyclosporin A on experimental nephritis in rats (2): Cyclosporin A suppresses the development of accelerated passive Heymann nephritis]. 750 79


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