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)

Proteinuria associated with acute heart disease was studied prospectively in 160 patients admitted to the coronary care unit with suspected AMI. Series 1 comprised 150 patients, divided into the following groups: AMI, 27 UAP, 43 AP, 22 NIP and 18 excluded. Albumin and creatinine were measured in the first urine passed after admission (sample 1) and the first morning urine the following 2 days (samples 2 and 3). The ACR was significantly higher in the AMI and UAP groups than in the other patient groups (p < 0.0001). There was no significant difference of ACR between the AMI and UAP in sample 1 (p = 0.31). In the AMI, UAP and AP groups ACR was significantly higher in sample 1 than in samples 2 and 3 (p < 0.005). In the NIP group there were no significant differences between sample 1 versus samples 2 and 3 (p = 0.06). Series 2 comprised 10 patients: 8 AMI, 1 UAP and 1 AMYO. ACR were measured in all specimens voided during the period of observation. ACR can oscillate within hours between normal concentrations and concentrations well into or above the microalbuminuric range. We propose the term episodic albuminuria for this reversible, switch-like change in renal function. The albuminuric episodes lasted 90-600 minutes. Maximum values for ACR were between 133-790 mumol/mol or 78-466 mg/g. In healthy, resting individuals ACR is < 50 mumol/mol (< 30 mg/g). The rapid changes in glomerular permeability may reflect systemic changes in endothelial permeability in the affected individuals. We speculate that atrial natriuretic peptide (ANP) may be a mediator of this type of albuminuria.
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PMID:Albuminuria in ischemic heart disease. 1038 13

Timed urine collections are difficult to use in clinical practice owing to inaccurate collections making calculations of the 24-h albumin or protein excretion questionable. One of our goals was to assess the 'correction' of urinary albumin and (or) protein excretion by dividing these by either the creatinine concentration or the term, (specific gravity-1)x100(1). The 24-h creatinine excretion can be estimated based on the patients' gender, age and weight. We studied the influence of physiological extremes of hydration and exercise, and protein and creatinine excretion in patients with or suspected kidney disorders. Specimens were collected from healthy volunteers every 4 h during one 24-h period. We assayed the collections individually to give us an assessment of the variability of the analytes with time, and then reassayed them after combining them to give a 24-h urine. For all volunteers, the mean intra-individual CVs based on the 4-h collections expressed in mg/24 h were 80.0% for albumin and 96.5% for total protein (P0.2). The CVs were reduced by dividing the albumin or protein concentration by the creatinine concentration or by the term, (SG-1)x100. This gave a CV for mg albumin/g creatinine of 52% (P<0.1 vs. albumin mg/g creatinine); mg protein/g creatinine of 39% (P<0.05 vs. mg protein/g creatinine); mg albumin/[(SG-1)x100] of 49% (P<0.1 vs. albumin)/[(SG-1)x100]; and mg protein/[(SG-1)x100] of 37% (P<0. 05 vs. mg protein)/[(SG-1)x100]. For the 68 subjects in the study, the strongest correlation was between the creatinine concentrations and the 24-h urine volume: r=0.786, P<0.001. The correlation of (SG-1)x100 vs. the 24-h urine volume was: r=0.606, P<0.001; for (SG-1)x100 and the creatinine concentration, the correlation was: r=0.666, P<0.001. Compared to the volunteers, the albumin and protein excretion in mg/24 h were more variable in the patients. The same was true if the albumin or protein concentrations were divided by the creatinine concentration or by (SG-1)x100. Protein and albumin concentrations were lower in dilute urines. Dividing the albumin or protein concentrations by the creatinine concentration reduced the number of false negative protein and albumin results. Dividing the albumin or protein values in mg/24 h by (SG-1)x100 eliminated fewer false negatives. Albumin concentrations increased significantly after vigorous exercise. The increase was almost eliminated when the albumin result was divided by the creatinine concentration suggesting that a decreased urine flow and not increased glomerular permeability causes an increase of post-exercise albuminuria. The same was true for proteinuria. A dipstick test plus an optical strip reader that can measure urine protein, albumin, and creatinine and calculate the appropriate ratios provides a better screening test for albuminuria or proteinuria than one measuring only albumin or protein.
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PMID:Urinary protein and albumin excretion corrected by creatinine and specific gravity. 1072 80

Initial studies showing an approximately 80% rate of progression from microalbuminuria (MA) to proteinuria in type 1 diabetic patients led to the broad acceptance of MA as a useful clinical predictor of increased diabetic nephropathy (DN) risk. Some MA patients, however, have quite advanced renal structural changes, and MA may, in these cases, be a marker rather than a predictor of DN. More recent studies have observed only about a 30-45% risk of progression of MA to proteinuria over 10 years, while about 30% of type 1 diabetic patients with MA became normoalbuminuric and the rest remained microalbuminuric. The finding that some MA patients have only mild diabetic renal lesions is consistent with the lower than originally estimated risk of progression from MA to proteinuria and with the notion that some MA patients revert to normoalbuminuria. To increase the complexity of the scenario, some normoalbuminuric long-standing type 1 diabetic patients have well-established DN lesions and approximately 40% of all patients destined to progress to proteinuria are normoalbuminuric at initial screening, despite many years of diabetes. A similar picture is emerging in type 2 diabetic patients, although fewer studies have been conducted. Thus, the predictive precision for MA to progress to overt nephropathy over the subsequent decade or so is considerably less than originally described. It is unclear whether this is due to changes in the natural history of DN resulting from improved glycemia and blood pressure control, or whether there were overestimates of risk in the original studies due to the small sample sizes, post hoc analyses, and variable MA definitions. Albumin excretion rate (AER) remains the best available noninvasive predictor of DN risk and should be regularly measured according to established guidelines. However, AER may be unable to define patients who are safe from or at risk of DN with an accuracy that is adequate for optimal clinical decision making or for the design of certain clinical trials. Investigations into new risk markers or into the combined use of several currently available predictive parameters are needed.
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PMID:The need for early predictors of diabetic nephropathy risk: is albumin excretion rate sufficient? 1096 21

The likely role of albumin in the induction tubulo-interstitial injury in proteinuria has stimulated considerable interest in the entry of albumin into the proximal tubule and its subsequent uptake by proximal tubular cells. Currently, there is considerable controversy over the degree of glomerular permeability to albumin. After filtration, however, albumin binds to megalin and cubulin, two giant receptors in the apical membrane of proximal tubular cells. Albumin is subsequently re-absorbed by proximal tubular cells by receptor-mediated endocytosis, a process subject to complex regulation. The interaction of albumin with proximal tubule cells also leads to the generation of intracellular signals. The understanding of these pathways may provide important insights into the pathogenesis of renal scarring in proteinuria.
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PMID:Mechanisms of albumin uptake by proximal tubular cells. 1115 55

Overt nephrotic syndrome is characterized by albumin and fibrinogen hyperproduction and reduced very low density lipoprotein apolipoprotein B-100 (VLDL apoB-100) clearance. Whether similar changes also occur in low-grade proteinuria is not known. Thus we measured albumin, fibrinogen, and VLDL apoB-100 kinetics in six patients with modest proteinuria and normal creatinine clearance (P) and in ten control subjects (C) by leucine tracer infusion and precursor-product relationships. In P, plasma albumin concentration was decreased (P < 0.003), whereas concentrations of fibrinogen and VLDL apoB-100 were increased (P < 0.001). In P, albumin fractional secretion rate (FSR) was increased (P < 0.01), fibrinogen FSR was normal, and VLDL apoB-100 FSR was decreased (P < 0.03). As a result, in P, absolute secretion rates (ASR) of albumin and fibrinogen were increased (P < 0.03), whereas VLDL apoB-100 ASR was normal. Albumin FSR was inversely correlated to oncotic pressure in P but not in C. These findings suggest that low-grade nephrotic proteinuria is characterized by simultaneous multiple alterations in turnover rates of albumin, fibrinogen, and VLDL apoB-100. Their pathogenesis, however, appears to be multifactorial.
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PMID:Plasma protein synthesis in patients with low-grade nephrotic proteinuria. 1125 66

Nephrotic patients show various abnormalities in protein kinetics. Plasma albumin levels and the total plasma albumin pool are reduced. The rate of hepatic absolute and fractional albumin synthesis are increased. Transferrin synthesis is also increased. Fibrinogen levels are elevated in nephrotic syndrome because of an increase in the hepatic synthesis. Regulation of albumin and fibrinogen synthesis seems to be coordinated. A low protein diet has been proposed as a therapeutic tool in nephrotic patients--clinical studies have shown that such a diet reduces proteinuria and increases renal survival. Nephrotic patients can adapt to moderate protein restriction with no sign of malnutrition and maintenance of a neutral nitrogen balance. Albumin and fibrinogen synthesis are ameliorated by dietary protein restriction and these changes are correlated with the beneficial effect of the diet on proteinuria.
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PMID:Changes of protein kinetics in nephrotic patients. 1179 Sep 48

Monotherapy frequently does not cause adequate blood pressure (BP) reduction and goal BP is not achieved. This double-blind, randomized, crossover, placebo-controlled study investigated, using a factorial design, the interaction between a dihydropyridine calcium channel blocking drug (felodipine 5 mg) and an angiotensin type I receptor blocking drug (candesartan 16 mg) on the control of BP as assessed by 24-h ambulatory monitoring. A total of 31 elderly patients with systolic hypertension completed all four arms of the study. Candesartan and felodipine lowered mean 24-h BP to a similar extent (candesartan 12.2 +/- 2.6/7.5 +/- 1.8; felodipine 11.9 +/- 2.2/5.7 +/- 1.4 mm Hg). The combination lowered it by 21.0 +/- 2.1/11.2 +/- 1.2 mm Hg, and this fall was significantly greater than with either of the monotherapies (P < .005) and was fully additive with no interactive term. The responder rate with the combination (90%) was greater than with candesartan (61%) or felodipine (55%). Microalbuminuria or proteinuria was present in 12 of 31 patients at randomization despite previous BP control. Candesartan and the combination both reduced urinary albumin excretion. Albumin excretion was not reduced by felodipine despite BP control similar to that achieved with candesartan. Side effects were infrequent and were fewer on the combination than on placebo or on the monotherapies. The combination of felodipine 5 mg and candesartan 16 mg has additive effects on BP in elderly patients with systolic hypertension. The combination was well tolerated and is suitable for use in patients who do not have an adequate response to monotherapy.
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PMID:A comparison of candesartan, felodipine, and their combination in the treatment of elderly patients with systolic hypertension. 1207 57

This review covers lipids, apolipoproteins, and receptors involved in the dyslipidemia of the nephrotic syndrome in humans and in rat or mouse models of the syndrome. It emphasizes research published during the last decade, though earlier work is cited. The focus is on the biosynthesis and catabolism of the plasma lipoprotein density classes and the role of receptors and enzymes in regulating lipoprotein metabolism in nephrosis. Although the factors responsible for the initiation of the hepatic and peripheral cellular responses to proteinuria and hypoalbuminemia remain elusive, recent work highlights the increased risk of atherosclerosis and the progression of renal disease associated with nephrotic dyslipidemia. Understanding of the role of the kidney in the catabolism of apolipoproteins entering the glomerular filtrate has been enhanced by the discovery of the receptor-mediated uptake of apolipoprotein A-I, the main apoprotein of HDL. The following aspects of lipid and lipoprotein metabolism in relation to nephrosis are discussed, with attention paid to differences between experimental nephrosis and the human nephrotic syndrome:(1) Albumin metabolism (2) Lipoprotein metabolism (3) Receptors (4) LCAT and CETP (5) Hepatic and Lipoprotein Lipase (6) Lipid metabolism (7) Lipiduria (8) Hypotheses and Questions (9) Summary.
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PMID:Lipoprotein metabolism in the nephrotic syndrome. 1213 20

The progression of renal disease correlates strongly with hypertension and the degree of proteinuria, suggesting a link between excessive Na+ reabsorption and exposure of the proximal tubule to protein. The present study investigated the effects of albumin on cell growth and Na+ uptake in primary cultures of human proximal tubule cells (PTC). Albumin (1.0 mg/ml) increased cell proliferation to 134.1 +/- 11.8% (P < 0.001) of control levels with no change in levels of apoptosis. Exposure to 0.1 and 1.0 mg/ml albumin increased total 22Na+ uptake to 119.1 +/- 6.3% (P = 0.005) and 115.6 +/- 5.3% (P < 0.006) of control levels, respectively, because of an increase in Na+/H+ exchanger isoform 3 (NHE3) activity. This was associated with an increase in NHE3 mRNA to 161.1 +/- 15.1% (P < 0.005) of control levels in response to 0.1 mg/ml albumin. Using confocal microscopy with a novel antibody raised against the predicted extracellular NH2 terminus of human NHE3, we observed in nonpermeabilized cells that exposure of PTC to albumin (0.1 and 1.0 mg/ml) increased NHE3 at the cell surface to 115.4 +/- 2.7% (P < 0.0005) and 122.4 +/- 3.7% (P < 0.0001) of control levels, respectively. This effect was paralleled by significant increases in NHE3 in the subplasmalemmal region as measured in permeabilized cells. These albumin-induced increases in expression and activity of NHE3 in PTC suggest a possible mechanism for Na+ retention in response to proteinuria.
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PMID:Effects of pathophysiological concentrations of albumin on NHE3 activity and cell proliferation in primary cultures of human proximal tubule cells. 1279 7

Albumin filtered by the glomerulus is reabsorbed in the proximal tubule. We have shown previously that proteinuria stimulates the proximal tubular Na(+)/H(+) exchanger 3 (NHE3) in rats. Activation of NHE3 may be a pathophysiologically important factor in the development of renal salt and water retention observed in the nephrotic syndrome. For examining whether albumin is a specific inducer of proximal tubular Na(+)/H(+) exchange and to determine the molecular mechanisms by which it regulates Na(+)/H(+) exchange, the effect of albumin on NHE3 in opossum kidney cells was studied. Albumin activated Na(+)/H(+) exchange in a time- and dose-dependent manner up to 100% in 48 h. In the early phase of stimulation (2 to 12 h), NHE3 activity was increased without changes in NHE3 protein and mRNA. At 24 h, increased NHE3 activity was accompanied by increase in cell surface NHE3 protein. The increase in surface NHE3 was associated with increased bidirectional trafficking of NHE3 protein between intracellular compartments and the cell surface. At 48 h, total cell NHE3 protein abundance and mRNA were increased as well. Whereas NHE3 translation was increased, NHE3 protein half-life remained unchanged. The effects of albumin on NHE3 protein abundance were modified by hydrocortisone in a complicated pattern. These results indicate that albumin directly regulates proximal tubular NHE3 at multiple levels.
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PMID:Albumin regulates the Na+/H+ exchanger 3 in OKP cells. 1463 28


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