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)

We describe a new application of high-performance aqueous gel permeation chromatography for the analysis of human proteinuria. Separations of urinary proteins from normal subjects and patients with renal impairment were performed with TSK G 3000 SW columns. The effects of pH and ionic strength of the eluent on the separation of urinary proteins were investigated. Albumins were selectively separated from urine by affinity chromatography on Blue Sepharose CL-6B. According to the results of clinical investigations, urinary protein pattern derived from gel permeation chromatography revealed a good prediction of the site of renal involvement. Predominant excretion of proteins with lower molecular weight than albumin correlated with tubular damage. Albumin and higher molecular weight protein patterns wer associated with glomerular disease. Absorbance measurements of the eluent at 280 nm were used for quantitative determination of total urinary protein. Gel permeation chromatography was compared to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the resulting protein patterns are in good agreement.
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PMID:Urinary protein profiling by high-performance gel permeation chromatography. 710 67

To study the role of the fixed anionic sites of the glomerular capillary wall in protein filtration, the negative charges were neutralized in vivo. With systemic infusion of the polycation protamine sulfate, glomerular staining for polyanion was reduced and protein excretion increased by 154%. To avoid systemic side effects in subsequent studies, small doses of a polycation were infused directly into one renal artery. The contralateral kidney was infused with the vehicle solution. Albumin excretion from the experimental kidneys in the first 1-hr collection after infusing 0.5 mg protamine sulfate was 24.3 +/- 6.3 micrograms/min/kidney (N = 13; P less than 0.01). Albuminuria declined during the subsequent 3 hr with a second infusion inducing a second proteinuric response. The degree and longevity of the albuminuric response was correlated directly to the dose of protamine sulfate. The polycations hexadimethrine and poly-l-lysine also induced proteinuria. The increased protein excretion consisted of albumin; the excretion of nonalbumin protein was identical in the experimental and control kidneys. Hemodynamic factors did not explain the increase in proteinuria. Morphologically, the polycation-treated kidneys showed scanty foot process fusion and a decrease in free negative sites in the lamina rarae of the glomerular basement membrane. The results strongly support an important role for glomerular charge in preventing filtration of circulating plasma albumin.
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PMID:Glomerular charge and urinary protein excretion: effects of systemic and intrarenal polycation infusion in the rat. 713 58

Albumin clearance and proteinuria selectivity were studied in 61 patients with diabetes mellitus of different severity by means of disc-electrophoresis. It was shown that the total protein excretion and albumin clearance are not dependent on the disease severity, but they are more intensive in patients with pronounced nephropatic symptoms. 3 degrees of proteinuria selectivity were detected in the patients examined: high, moderate and low (39.3, 44.3 and 16.4% of the patients, respectively). The extent of proteinuria selectivity was not dependent on diabetes severity and decreased in the process of the renal affection development, showing the change in the glomerular basal membrane permeability. The studies of proteinuria selectivity may serve as an additional criterion for early glomerulosclerosis diagnosis and therapy in diabetes mellitus.
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PMID:[Comparative study of dysproteinemia and proteinuria in diabetic nephroangiopathies]. 729 Nov 57

Deposition of antibody and activation of the complement cascade are important in both naturally occurring glomerulonephritis and in experimental models including passive Heymann nephritis. We studied the effect of antibody and complement on albumin permeability of isolated glomeruli to determine the role of the terminal complement components (C5-C9) in mediating the proteinuria in nephritis. Isolated glomeruli were treated with anti-Fx1a (Heymann antibody) and then incubated them with pooled human serum, serum in which complement had been inactivated by heat, or serum deficient in C6 or C7. The albumin reflection coefficient (sigma albumin) was calculated from the volumetric response of glomeruli to transcapillary oncotic gradients produced by albumin or high molecular weight neutral dextran (252 kD). Convectional permeability to albumin (Palbumin) was calculated as 1-sigma albumin. Albumin permeability of control glomeruli was not different from 0. Albumin permeability was not altered by antibody alone but was increased to 0.65 +/- 0.04 when antibody treated glomeruli were incubated for 10 minutes with pooled serum as a source of complement. Heat treatment of serum to inactivate complement prevented the increase in permeability. Incubation for 10 minutes with serum without antibody pretreatment caused a lesser increase in permeability of isolated glomeruli (0.18 +/- 0.06). Serum deficient in either C6 or C7 did not cause an increase in albumin permeability of antibody pre-treated glomeruli, but incubation with a combination of these sera (now containing the complete cascade) increased permeability to the same extent as did pooled normal serum (0.58 +/- 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:C5b-9 increases albumin permeability of isolated glomeruli in vitro. 752 24

The reactive vascular-injuring amino acid homocysteine was previously shown to be increased in plasma in diabetic patients with clinical signs of nephropathy. In this study, plasma homocysteine was measured in type 1 diabetic patients with normoalbuminuria (n = 22), microalbuminuria (n = 40) and proteinuria (n = 14) in order to investigate whether plasma homocysteine levels are increased already at the stage of incipient nephropathy, i.e. microalbuminuria. Furthermore, patients were characterized according to the degree of retinopathy. Plasma homocysteine in the whole population (n = 76) was related to B-Folate (r = 0.38, p < 0.01), S-Creatinine (r = 0.55, p < 0.001), S-Urea (r = 0.37, p < 0.01), U-Albumin (r = 0.46, p < 0.001), urinary N-acetyl-beta- glucosaminidase (r = 0.40, p < 0.001), systolic blood pressure (r = 0.36, p < 0.01) and diabetes duration (r = 0.44, p < 0.001). There were no differences in plasma homocysteine levels between patients with normoalbuminuria (8.0 +/- 1.7 mumol l-1; mean +/- SD) and those with microalbuminuria (9.1 +/- 3.4 mumol l-1). However, patients with clinical signs of nephropathy had higher plasma homocysteine levels (12.9 +/- 5.7 mumol l-1, p < 0.01) compared to the other two groups. There was no association between plasma homocysteine levels and different degrees of retinopathy. Thus, the present study does not show any relation between plasma homocysteine levels and early stages of diabetic nephropathy or retinopathy indicating that elevated concentrations of plasma homocysteine does not explain the increased risk for atherosclerosis observed in patients with microalbuminuria.
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PMID:Lack of association between plasma homocysteine levels and microangiopathy in type 1 diabetes mellitus. 770 67

Proteinuria was characterized by SDS-PAGE and by immunoblotting with anti-human albumin sera for the detection of urinary polymers of albumin (PA) in 40 patients with biopsy proven lupus glomerulonephritis (LN) (6 pts class III WHO, 24 pts class IV, 10 pts class V) with various clinical presentations (nephrotic syndrome with normal or impaired renal function, 14 pts; urinary abnormalities with normal or impaired renal function, 21 pts; clinical remission, 5 pts); in 25 pts, for whom the characterization of proteinuria and the renal biopsy were performed at the same time, the activity and chronicity index scores were calculated. The mixed SDS-PAGE patterns, characterized by the presence of low molecular weight proteins, were the more frequently found; the mixed patterns were significantly associated with interstitial leukocyte infiltration (p = 0.05) and glomerular sclerosis (p = 0.046) and nonsignificantly associated with higher values of serum creatinine; no SDS-PAGE pattern had predictive value on functional outcome at 36 months. Albumin polymers were present in 67% of pts; in active disease they were present in 33% of class III, in 100% of class IV and in 45% of class V WHO (p = 0.026); PA were not present in 5 pts with clinical remission (4 class IV and 1 class V WHO). The presence of PA was significantly associated with high values (> 10) of activity index (p = 0.009) and with extracapillary proliferation (p = 0.041). Serum creatinine was lower in patients without PA (Scr 1.0 +/- 0.4 mg/dl) than in those with PA (Scr 1.5 +/- 1.0 mg/dl), but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:SDS-PAGE patterns and polymeric albumin in proteinuria of lupus glomerulonephritis. 773 85

Albumin excretion, Analysis of urinary proteins by polyacrylamide gel electrophoresis (PAGE), and clinical evaluation were performed in 90 HIV-infected patients to assess subclinical renal involvement in HIV infection. Thirteen percent of all patients showed an albumin excretion > 20 mg/liter. Seven of four homosexual patients had albuminuria. Albuminuria occurred exclusively with T4 cell counts below 200/mm3. Polyacrylamide gel electrophoresis indicated glomerular lesions and showed no tubular proteinuria in patients with increased albumin excretion. It is concluded that subclinical renal involvement is not uncommon in HIV infection with T4 cell counts > 200/mm3. HIV-associated nephropathy and heroin-associated nephropathy may not be the main causes of renal involvement. In some cases, opportunistic viral infections may be the cause of microalbuminuria.
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PMID:Albuminuria in HIV-infected patients. 791 29

Microalbuminuria is thought to be rare in people with insulin-dependent diabetes mellitus (IDDM) for less than 5 years. We measured its prevalence in 733 clinic-attending IDDM patients with diabetes duration of 1-5 years in two large multicenter studies [EURODIAB IDDM Complications Study and the World Health Organization (WHO) Multinational Study]. We also compared characteristics of microalbuminuric patients with IDDM for 1-5 years versus more than 5 years' duration. Albumin excretion rate was measured from a timed 24-h urine collection in the EURODIAB Study. Proteinuria was measured by the salicylsulphonic acid test in the WHO Study. The prevalence of microalbuminuria (20-200 micrograms/min, EURODIAB) was 18% [95% confidence interval (CI) 13%-22%)]. The prevalence of light proteinuria was 15% (9%-20%, WHO study). Raised protein excretion was a consistent finding in 34 of the 36 centers. The increased cardiovascular risk (raised blood pressure and total cholesterol) associated with microalbuminuria in patients with IDDM for more than 5 years was also apparent in those with diabetes for 1-5 years. However, repeat urine testing suggested that microalbuminuria before 5 years was more likely to be transient or reversible. In conclusion, these two studies in 36 centers, which used different methods more than 10 years apart, show consistently that raised urinary albumin excretion occurs before 5 years of IDDM. The clinical significance of this needs to be examined by prospective observation.
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PMID:Microalbuminuria is not rare before 5 years of IDDM. EURODIAB IDDM Complications Study Group and the WHO Multinational Study of Vascular Disease in Diabetes Study Group. 808 53

A modified rat kidney preparation was used to explore how changes in hydrostatic pressure affect the permselective properties of the glomerular capillary bed. The maximally vasodilated kidneys of 18 rats were perfused with albumin solutions (16.7 g l-1) at different flow rates and hence arterial pressures (PA). One kidney in each rat was exposed to pressure elevations with the other kidney serving as a control perfused at constant PA of about 100 mmHg. Both the vascular resistance to flow and the glomerular filtration rate (GFR 34.6 +/- 2.9 ml min-1 100 g-1) were similar in the two kidneys at equal PA and remained constant throughout the experiment. The ratio of albumin clearance over GFR (theta) was initially around 0.4% at constant PA and gradually increased during 1.5 h to reach 0.7% at the end of the experiment. A direct increase of PA from 100 to 200 mmHg for 15 min resulted in a calculated increase of the effective glomerular filtration pressure gradient of 10-15 mmHg and in a two-fold increase of theta when measured at an identical PA of 100 mmHg. Albumin clearance was almost fully normalized within 20 min similar to that observed in e.g. skeletal muscle. However, the glomerular capillary barrier seemed to be far more sensitive to elevations of hydrostatic pressure than other capillary walls which require capillary pressure increments of 60 mmHg in order to induce similar reversible changes in permeability. Therefore, we conclude that an elevated PGC per se induces changes of glomerular permselectivity, which may have important pathophysiological implications during conditions of proteinuria.
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PMID:Reduced permselectivity in isolated perfused rat kidneys following small elevations of glomerular capillary pressure. 819 99

The nephrotic syndrome is a consequence of urinary loss of intermediate-sized plasma proteins and the resulting homeostatic responses to those losses. Plasma protein composition is changed greatly. Pathophysiologic changes are a consequence of the nature of the proteins lost and of the proteins that are increased in plasma to replace them. Plasma oncotic pressure (pi) falls because of the replacement of relatively small plasma proteins by larger ones. Decreased pi increases transudation of fluid into the interstitium and favors edema. This is exacerbated by causing renal insensitivity to atrial natriuretic factor (ANF), primary renal sodium retention, and plasma volume expansion. Many proteins lost in the urine, such as erythropoietin and IgG, are not defended by increased synthesis. Their loss may result in reduced immunity, anemia, and endocrinopathies. Albumin synthesis can be increased by dietary protein augmentation; however, urinary protein losses also increase, offsetting any palliative effect of increased albumin synthesis on albumin stores. The synthesis of many other proteins secreted by the liver is also increased, causing an elevation in plasma levels of several large proteins, including lipoproteins and elements of the coagulation cascade. This results in hyperlipidemia and, in conjunction with the urinary loss of smaller proteins that impede coagulation, a hypercoagulable state. Lipoprotein catabolism is also reduced as a consequence of proteinuria contributing to increased lipid levels.
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PMID:Nonrenal complications of the nephrotic syndrome. 819 77


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