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

A 22 year old woman presented with lupus nephritis, hypertension, and intractable nephrotic syndrome. Albumin and furosemide given intravenously was ineffective. Captopril administered in a daily dose of 62.5 mg was associated with a reduction in proteinuria from 28 g/24 hours to 11.5 g/24 hours over 10 weeks, resulting in a weight reduction of 16 kg. This was achieved with relative preservation of renal function. Captopril should be considered in the treatment of intractable proteinuria in patients with lupus nephritis, or when cytotoxic drugs are refused, because of its efficacy and relative safety. Captopril should, however, be used as an adjunct and not as a substitute for standard treatment.
 ...
PMID:Antiproteinuric effect of captopril in a patient with lupus nephritis and intractable nephrotic syndrome. 224 Dec 92

The nephrotic syndrome is characterized by the increased urinary excretion of albumin and of other serum proteins of intermediate molecular weight accompanied by a decrease in their serum concentration. Albumin synthesis is increased at the level of mRNA synthesis in response to decreased serum oncotic pressure. However, the magnitude of these responses is dependent upon dietary protein and is insufficient to normalize serum albumin. The absolute rate of albumin catabolism is decreased, serving to normalize serum albumin stores, but in contrast to what occurs in other hypoalbuminemic states, the fractional rate of albumin catabolism is increased. This observation is consistent with a hypothesis that increased renal catabolism contributes to total albumin catabolism in nephrosis. Like albumin, IgG is lost in the urine, its serum concentration is decreased, and the fractional rate of its catabolism is increased, suggesting that the kidney contributes to IgG catabolism in the presence of proteinuria. IgG synthesis responds in a variable fashion in the nephrotic syndrome, and may be decreased, thus contributing to its reduced serum concentration. In contrast, the serum concentration of the high-molecular-weight immunoglobulin IgM is increased, as is the serum concentration of a variety of high-molecular-weight liver-derived proteins. It is unknown by what mechanism serum IgM concentration is increased, but this response serves to defend serum protein concentration and oncotic pressure.
 ...
PMID:Metabolism of albumin and immunoglobulins in the nephrotic syndrome. 225 74

Proteinaceous cast formation in the distal nephron of the kidney from low molecular weight proteinuria is a significant, but poorly characterized, cause of renal failure. To study this phenomenon, we: (a) microperfused the loop segment (LS) of rats in vivo with artificial tubule fluid (ATF) containing four different low molecular weight proteins, 0.01-50 mg/ml, to detect alterations in LS function, and (b) examined the interaction between several proteins and Tamm-Horsfall glycoprotein (THP) in vitro with turbidity and dynamic light-scattering measurements. Perfusion of the LS for less than 2 min with cast-forming proteins (Bence Jones protein [BJP3] and myoglobin) decreased chloride absorption and elevated early distal tubule fluid (ED) [Cl-], compared with results obtained with control perfusions that used ATF alone. BJP3 decreased chloride absorption in a concentration-dependent fashion. Perfusion with non-cast-forming proteins (albumin and BJP1) enhanced chloride absorption and decreased ED [Cl-]. In vitro, proteins that had isoelectric points (pI) greater than 5.1 aggregated with THP. Aggregation was enhanced with increasing [NaCl] or [CaCl2]. Albumin (pI 4.8) and beta-lactoglobulin (pI 5.1) did not coprecipitate. The molecular size of THP alone increased when [NaCl] greater than 80 mM. Thus, cast-forming proteins aggregated with THP in vitro and caused in vivo LS dysfunction, which elevated ED [Cl-], facilitating aggregation. In contrast, non-cast-forming proteins either did not interact with THP or lowered ED [Cl-], which did not provide an environment for aggregation. Altered LS function and interaction of some proteins with THP were related to different physicochemical properties of the proteins and independently contributed to the formation of proteinaceous casts in the kidney.
 ...
PMID:Mechanisms of intranephronal proteinaceous cast formation by low molecular weight proteins. 229 21

Clinical data of 65 patients with myeloma were analyzed to identify factors associated with hypoalbuminemia. The serum albumin level was not affected by patient age and gender, type of myeloma, and the occurrence of Bence Jones protein, lytic bone lesions, or hypercalcemia, and it was not related to changes in body weight or in liver and renal function. The albumin level, lower in patients with proteinuria, was unrelated to severity of proteinuria. Albumin level correlated significantly with the monoclonal IgG levels, hemoglobin concentration, clinical stage of disease, and estimated body tumor burden. Further analysis indicated the disease stage or the tumor burden as the dominant factor in determining albumin level. An albumin level of 29.0 g/L or less identified unequivocally advanced disease. Practically all patients with stage III myeloma had a serum albumin level of 37.0 g/L or less. Thus, hypoalbuminemia is primarily related to the extent of myeloma proliferation and is therefore of diagnostic and prognostic importance.
 ...
PMID:Hypoalbuminemia in patients with multiple myeloma. 200 Nov 48

Exercise performance, glomerular filtration rate (GFR), and urinary filtration of proteins during static pool rowing and cycling to exhaustion were studied in trained rowers. The peak VO2 and heart rate were higher during rowing than during cycling. There was a reduction in plasma volume and an increase in lactate concentration after exercise; however, no significant difference was noted between rowing and cycling in either case. Postexercise proteinuria was increased 8 and 11 times, and albuminuria 25 and 20 times after rowing and cycling exercises, respectively. There was no difference between these exercises in terms of protein or albumin excretion. There was no change in postexercise GFR. Albumin clearance was increased 18 and 20 fold after rowing and cycling, respectively. A significant, but low correlation, r = 0.56, was noted between albumin excretion and postexercise blood lactate concentration. Thus, no difference in the effect on kidney response was found between static pool rowing and cycling to exhaustion in these athletes.
 ...
PMID:Postexercise proteinuria in rowers. 238 16

It has been established previously that nephrotic hyperlipidemia is characterized by both an increase in lipid synthesis and a defect in removal of lipoproteins. The relationship between these defects and altered albumin metabolism is uncertain. One hypothesis is that hepatic lipogenesis increases in parallel with albumin synthesis. To test this hypothesis, albumin synthesis was increased in nephrotic rats fed an 8.5% protein diet (LPN) by increasing dietary protein to 40% (HPN). Proteinuria was modulated in half of the rats fed 40% protein by enalapril (HPE). Albumin synthesis was the same in both HPN and HPE, but proteinuria was reduced in HPE compared to HPN, and so were serum cholesterol and triglycerides (TG). To examine the effect of serum albumin on lipid clearance in the absence of proteinuria, plasma clearance of chylomicrons (CM) and VLDL was measured in Nagase analbuminemic rats (NAR) and found to be no different than in normal SD rats. When proteinuria was induced in NAR and in SD rats, a severe and identical defect in both CM and VLDL clearance was acquired in both groups and blood lipid levels were increased to a similar degree in both groups. Neither hyperlipidemia nor defective removal of lipoproteins from the circulation are linked to albumin synthesis or serum albumin concentration but result, at least in part, from proteinuria. Postheparin lipoprotein lipase (LPL) activity was reduced slightly in nephrotic animals compared to nonnephrotic controls, but the most striking finding was a highly significant decrease in postheraprin LPL activity in normal NAR compared to SD rats (P less than 0.001), suggesting that reduced LPL activity is not responsible for reduced clearance of CM and VLDL in nephrotic rats.
 ...
PMID:Proteinuria, not altered albumin metabolism, affects hyperlipidemia in the nephrotic rat. 238 6

The excretion of proteins differing in charge (the different immunoglobulin subclasses) and/or size (albumin, immunoglobulins) were investigated in normal subjects in a number of physiological conditions aiming at the evaluation of renal charge permselectivity. In 101 randomly selected normal subjects the urinary excretion rates of albumin, IgG4 (anionic proteins) and of total IgG (mostly cationic) were evaluated in basal conditions; the protein/creatinine urinary ratio and protein clearances were assessed in part of them. In addition, the intra- and interday variations of protein excretion were evaluated. Protein clearances were measured in a sample group after standardized physical exercise, after an amino acid load, and in orthostatism. Albumin, IgG4 and IgG were assayed using sensitive methods developed in our laboratories. The excretion rate values of albumin, IgG4 and total IgG (median, interquartile range) were 4.36 micrograms/min, (2.58-6.59), 4.25 ng/min (2.6-7.6), and 1.47 micrograms/min (0.85-2.44), respectively. The clearances of the three proteins (mean +/- SD) were 0.13 +/- 0.07, 0.017 +/- 0.012 and 0.14 +/- 0.08 ml/min x 10(-3), respectively. The IgG4/IgG ratio averaged 0.1 and was always below 0.25. Protein excretion rates showed a noticeable variation during the day and from day to day. Physical exercise, the change of posture and the amino acid load significantly increased proteinuria but did not significantly modify the anionic/cationic immunoglobulin ratio. Thus, the anionic/cationic immunoglobulin ratio of about one tenth, substantially stable during dynamic tests, in normal subjects may be considered an index of physiological renal protein charge permselectivity.
 ...
PMID:Anionic versus cationic immunoglobulin clearance in normal subjects: a novel approach to the evaluation of charge permselectivity. 239 93

Part I highlights the mechanisms of glomerular filtration and tubular reabsorption of plasma proteins, selected characteristics of urinary proteins based upon electrophoretic properties and recent advances in clinical laboratory analysis of proteinuria. Both structural characteristic of the glomerular capillary wall and molecular properties of plasma proteins are important determinants of glomerular filtration. Proteins filtered by the glomerulus subsequently appear in urine only after escaping the efficient mechanisms of tubular reabsorption. Albumin is one such protein and constitutes the major protein in normal urine although trace amounts of alpha, beta, and gamma globulins are also detectable. Several techniques of protein analysis have thus been developed to specifically measure albumin as well as other plasma proteins. Other methods have been adapted to measure total urinary protein content enabling the clinician to readily monitor renal function in health and disease. The second part of this review will consider conditions associated with proteinuria in both asymptomatic individuals and patients with renal disease. Asymptomatic proteinuria encompasses states of excess protein excretion during conditions of orthostasis, exercise, travel to high altitude of fever. Proteinuria during renal disease has received considerable interest as a means to monitor kidney function. It is therefore classified according to the type of damage incurred: (1) glomerular-type where large molecular weight proteins are excreted (2) tubular-type where small molecular weight proteins are excreted and (3) mixed-type characterized by both large and small molecular weight proteinuria.
 ...
PMID:Normal and abnormal aspects of proteinuria. Part I: Mechanisms, characteristics and analyses of urinary protein. Part II: Clinical considerations. 242 51

The mechanism of the increased renal clearance of amylase and the amylase to creatinine clearance ratio (CAM/CCR) in acute pancreatitis remains controversial with both renal tubular dysfunction and altered glomerular permeability being invoked as explanations. To differentiate between these mechanisms, we investigated the quantity and character of protein excretion in 10 patients with pancreatitis. For a short period of time, seven of 10 patients had mild proteinuria with a mean protein excretion rate of 230 +/- 154 mg/24 hr. Proteinuria decreased in 9/9 survivors to 17 +/- 18 mg/24 hr. Albumin excretion rate initially was minimally increased in 10/10 patients with a mean of 61 +/- 40 mg/24 hr, decreasing during recovery in 8/9 survivors to 10.9 +/- 10.4 mg/24 hr (P less than 0.01). Electrophoresis of urine obtained during the acute phase consistently showed a low molecular weight proteinuria pattern that cleared with recovery. Twenty-one of 22 urinary samples with an elevated CAM/CCR had a low molecular weight protein pattern. All the above findings can be explained by alterations in renal tubular reabsorption of proteins without changes in glomerular permeability. In 2/4 patients a low molecular weight protein was present in urine specimens from the acute phase that was not present in highly concentrated urine specimens from the recovery period. This raises the possibility that an abnormal low molecular weight protein enters the serum in acute pancreatitis, which, after glomerular filtration, produces the renal tubular malfunction found in acute pancreatitis.
 ...
PMID:Urine protein excretion in acute pancreatitis. 243 Oct 86

Microalbuminuria is an early marker of prognostic significance in diabetic renal disease. The aim of the present study was to compare methods which do not require radioactive markers for estimating microalbuminuria (20-300 mg l-1) with a radioimmunoassay for albumin estimation. Albumin concentrations of 329 diabetic patients were measured using two laser turbidimetric methods for albuminuria and proteinuria, two semiquantitative tests (Albusure and Albustix), and a routine albumin radioimmunoassay. The four methods in the order laser immunoturbidimetric for albuminuria, laser turbidimetric for proteinuria, Albusure and Albustix gave the following results: sensitivity 0.97, 0.93, 0.97 and 0.81; specificity 0.92, 0.88, 0.94 and 0.55; positive predictive value for microalbuminuria 0.83, 0.75, 0.85 and 0.42; negative predictive value for microalbuminuria 0.99, 0.97, 0.99 and 0.88. We suggest that both laser turbidimetric methods are reliable and can replace methods with radioactive markers, the same being true for the Albusure test.
 ...
PMID:Comparison of methods for determination of microalbuminuria in diabetic patients. 252 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>