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)

Since carbohydrates-containing molecules are known to be preferentially altered in diabetes mellitus and that major functional and morphological alterations do occur during diabetes in the renal tissue, we revealed in the present study various lectin-binding sites in the glomerular wall of control and long-term diabetic animals. Lectin-binding sites specific to N-acetyl-galactosamine, N-acetyl-glucosamine, sialic acid, galactose and fucose were revealed using the appropriate lectin and the lectin-gold complex at the electron microscope level. Differences in intensity of labeling as well as in distribution were detected for several lectin-binding sites particularly in the glomerular basement membrane, reflecting the presence of additional glycoconjugates and changes in the molecular organization of the basement membrane components during diabetes. Alterations in the glycocomponents and the glycoproteins of the glomerular basement membrane as well as non-enzymatic glycosylation of the basement membrane components have been described in diabetes, going along with our present results. The alteration in the distribution of some lectin-binding sites gives support to modifications in the three dimensional organization of some glycoproteins which could occur in diabetes. Since the glomerular wall is actively involved in blood filtration, these changes may either induce, or result from, the loss in selective permeability and the massive proteinuria occurring during diabetes.
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PMID:Ultrastructural distribution of lectin-binding sites in the glomerular wall of streptozotocin-induced diabetic rats. 169 9

Glomerular epithelial cells (GECs) in vitro provide a useful model for the study of the mechanism(s) underlying the nephrotic syndrome of rats induced by the aminonucleoside of puromycin (PAN). Some of the toxicities of PAN are nonspecific, in that the constituent molecules of PAN (adenosine and puromycin) cause similar effects in vitro. These include GEC blebbing and rounding, reduced uptake of precursors of protein (leucine) and glycoprotein (glucosamine) synthesis, and increased permeability of the GEC membrane to adenosine. Some of the effects of PAN are not reproduced by adenosine or puromycin and are inhibited by the simultaneous presence of N6-monomethyl adenosine (MMA), a PAN analog and an in vivo blocker of nephrosis due to PAN. These processes may be related to the nephrotic syndrome and include the loss of adhesion to plastic; a reduction in the incorporation of 14C-glucosamine and 35S-sulfate both into molecules removable from the GEC surface by neuraminidase and into those moieties precipitated from the culture media by TCA; a marked reduction in the "ordering" of the lipids of the rigid GEC membrane, which is possibly dependent upon cell-surface proteins. These morphologic alterations in GECs and in the distribution of negatively charged molecules, which are either secreted or on the cell surface, correlate with observations made in PAN-induced nephrosis in rats in vivo. These include changes in the turnover and the array of sialic acid and heparan sulfate glycoprotein on the GECs and the glomerular basement membrane. The in vitro sensitivity of GECs to PAN and the effects of MMA suggest a role for these cells in in vivo aminonucleoside nephrotoxicity, where alterations in both the morphology and the anionic topology of GECs participate in the development of proteinuria.
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PMID:Effects of the aminonucleoside of puromycin on glomerular epithelial cells in vitro. 397 43

The mechanism of edema, proteinuria, hypertension (EPH)-gestosis-associated premature replacement of hyaluronic acid by sulphated glycosaminoglycans (GAGs) in the umbilical cord arteries is not known. It may result from altered biosynthesis, a different degradation rate or a combination of both phenomena. In order to solve this problem, it was decided to evaluate the biosynthesis and degradation of newly synthesized GAGs in the umbilical cord arteries of control newborns and those delivered by mothers with EPH-gestosis. Incorporation of radioactive precursors ([14C]glucosamine and [35S]sulphate) into GAGs and degradation of newly synthesized GAGs using the pulse-chase experiment were evaluated. We found that the investigated tissue slices incorporated distinctly less [14C]glucosamine into hyaluronic acid in comparison to controls. In contrast to that, the biosynthesis of sulphated GAGs did not change significantly. However, the degradation of newly synthesized sulphated GAGs was distinctly slower than in control tissues. It may be concluded that an EPH-gestosis associated decrease in hyaluronic acid content in the umbilical cord artery is a result of decreased biosynthesis of this substance, whereas an increase in sulphated GAGs-content is rather a result of slower degradation of newly synthesized GAGs.
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PMID:Glycosaminoglycan-biosynthesis in the wall of the umbilical cord artery and its alteration in EPH-gestosis. 907 17

Sulfated portions of glycosaminoglycan (GAG) side chains in heparan sulfate proteoglycan (HSPG) are thought to play an important role in charge-dependent selectivity of glomerular filtration against plasma proteins. Heparan sulfate N-acetylglucosamine N-deacetylase/adenosine 3'-phosphate 5'-phosphosulfate: unsubstituted glucosamine N-sulfotransferase (NDST) is the key enzyme regulating sulfation of GAG chains. In this study we investigated transcriptional expression of NDST-1, 1 of 4 isozymes of NDST, in glomeruli of rats with puromycin aminonucleoside (PAN) nephrosis. Nephrosis was induced in rats with a single intraperitoneal injection of 150 mg/kg PAN. On days 10 and 35, expression of NDST-1 messenger RNA (mRNA) in glomeruli was analyzed with the use of Northern-blot analysis. Immunohistochemical studies were also performed with the use of monoclonal antibodies that react specifically with the N-sulfated portion of the GAG chain of HSPG and agrin, a major core protein of HSPG in glomerular basement membrane (GBM). In addition, we studied the expression of NDST-1 mRNA in cultured glomerular epithelial cells (GECs) and glomerular mesangial cells in the presence of PAN. On day 10, when significant proteinuria developed, the ratios of glomerular expression of NDST-1 mRNA against glyceraldehyde-phosphate dehydrogenase mRNA in PAN-treated rats were decreased to 48% +/- 6% of those in controls (P<.05). Immunohistochemical studies revealed that staining for N-sulfated GAG chains of HSPG on GBM was markedly reduced on day 10 in PAN-treated rats but that staining for agrin was unchanged. In contrast, on day 35, when PAN-treated rats recovered from proteinuria, we noted no differences in glomerular expression of NDST-1 mRNA and staining intensity for N-sulfated GAG chains on GBM between PAN-treated rats and controls. Incubation of GECs for 24 hours in the presence of 50 ng/mL PAN resulted in the reduction of the expression of NDST-1 mRNA (67% +/- 12% of those in controls, P<.05). In summary, we found alteration of the expression of NDST-1 mRNA, accompanying a loss of N-sulfated GAG chains of HSPG on GBM without changes in the core protein agrin, in the course of PAN nephrosis. These data suggest an important role for this enzyme in heparan sulfate assembly in GBM and GEC and in the pathogenesis of proteinuria in PAN nephrosis.
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PMID:Altered expression of NDST-1 messenger RNA in puromycin aminonucleoside nephrosis. 1496 66

Reactive oxygen species (ROS) play a key role in the pathogenesis of proteinuria in glomerular diseases like diabetic nephropathy. Glomerular endothelial cell (GEnC) glycocalyx covers the luminal aspect of the glomerular capillary wall and makes an important contribution to the glomerular barrier. ROS are known to depolymerise glycosaminoglycan (GAG) chains of proteoglycans, which are crucial for the barrier function of GEnC glycocalyx. The aim of this study is to investigate the direct effects of ROS on the structure and function of GEnC glycocalyx using conditionally immortalised human GEnC. ROS were generated by exogenous hydrogen peroxide. Biosynthesis and cleavage of GAG chains was analyzed by radiolabelling (S(35) and (3)H-glucosamine). GAG chains were quantified on GEnC surface and in the cell supernatant using liquid chromatography and immunofluorescence techniques. Barrier properties were estimated by measuring trans-endothelial passage of albumin. ROS caused a significant loss of WGA lectin and heparan sulphate staining from the surface of GEnC. This lead to an increase in trans-endothelial albumin passage. The latter could be inhibited by catalase and superoxide dismutase. The effect of ROS on GEnC was not mediated via the GAG biosynthetic pathway. Quantification of radiolabelled GAG fractions in the supernatant confirmed that ROS directly caused shedding of HS GAG. This finding is clinically relevant and suggests a mechanism by which ROS may cause proteinuria in clinical conditions associated with high oxidative stress.
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PMID:Reactive oxygen species modulate the barrier function of the human glomerular endothelial glycocalyx. 2345 83

A 16-year-old man was transferred to our emergency department seven hours after ingesting 486 aspirin tablets. His blood salicylate level was 83.7 mg/dL. He was treated with fluid resuscitation and sodium bicarbonate infusion, and his condition gradually improved, with a decline in the blood salicylate level. However, eight days after admission, he again reported nausea, a venous blood gas revealed metabolic acidosis with a normal anion gap. The blood salicylate level was undetectable, and a urinalysis showed glycosuria, proteinuria and elevated beta-2 microglobulin and n-acetyl glucosamine levels, with a normal urinary pH despite the acidosis. We diagnosed him with relapse of metabolic acidosis caused by renal tubular acidosis.
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PMID:Late Metabolic Acidosis Caused by Renal Tubular Acidosis in Acute Salicylate Poisoning. 2718 39