Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01034 (cystatin C)
 3,397 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Seven infants (two French Canadian, four Ashkenazi Jewish, and one Greek) with massive selective hyperiminoglycinuria (proline, hydroxyproline, and glycine) were detected by urine screening in the second week of life. Follow-up investigations and family studies revealed that each subject had a benign condition, familial renal iminoglycinuria, an autosomal recessive condition. The family studies (Table 1 and Fig. 1) indicate the presence of at least two different mutant alleles segregating in this small group of probands. Hmozygotes of two forms and one genetic compound were identified. Quantitative studies revealed normal concentrations of proline and glycine in plasma (Fig. 2), normal maturation of creatinine clearance (as an index of glomerular filtration rate) (Fig. 3), and elevated renal clearance of proline and glycine (Table 2). Fractional excretion (CAA/CCR) of both proline and glycine in the probands was far in excess of that expected for the normal postnatal infant; FFPro and FEGly approached 100% of the filtered load on occasion (Fig. 4). A schedule of maturing tubular reabsorptive activity was apparent in the proband group. Proline reabsorption matured earlier than glycine reabsorption in the homozygotes (and the genetic compound) as it does in the normal infants (Fig. 5). Our findings suggest that three gene products serve net tubular reabsorption of imino acids and glycine in human kidney. One, affected by mutation in our patients, is responsible for a shared transport activity; a second with preference for proline, and not affected by the mutation, has an "early" schedule of postnatal maturation; and a third with preference for glycine, also not affected by the mutation, has a "late" schedule of maturation.
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PMID:Ontogeny of amino acid reabsorption in human kidney. Evidence from the homozygous infant with familial renal iminoglycinuria for multiple proline and glycine systems. 43 3

Cystatin C, a 13 kDa-protein, is produced by most nucleated cells and is catabolized by the renal tubular cells after passing the glomerular filter. It belongs to the family 2 of the cystatin superfamily of proteins. The function of cystatin C is to regulate the activity of cysteine proteinases and cystatin C seems to be the main cysteine proteinase inhibitor of most investigated human biological fluids. Its normal level in plasma is 0.8-2.5 mg/l, in cerebrospinal fluid 4-14 mg/l and in urine 0.03-0.3 mg/l. The production rate of cystatin C is remarkably constant and its plasma concentration can therefore be used as a reliable measure of the glomerular filtration rate (GFR). Indeed, the cystatin C plasma concentration is more closely correlated to the GFR than the plasma levels of creatinine and all other investigated low molecular weight proteins, including beta 2-microglobulin and retinol binding protein. Protein HC, alias alpha 1-microglobulin, is produced by the liver as a 27 kDa-glycoprotein. It belongs to the lipocalin superfamily of hydrophobic ligand binding proteins and more than 50% of the normal plasma amount of protein HC is present as a high molecular weight HC-IgA complex carrying antibody activity. The plasma concentration of free protein HC is, in contrast to that of HC-IgA, mainly determined by the GFR. The normal values for the plasma concentrations of HC-IgA and free protein HC are 36-620 mg/l and 14-26 mg/l, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diagnostic value of analysis of cystatin C and protein HC in biological fluids. 128 35

Serum concentrations of creatinine and of the three low molecular weight (LMW) proteins cystatin C, factor D of the complement system and beta 2-microglobulin were measured in 135 consecutive patients, whose glomerular filtration rates (GFR) were determined by Cr-EDTA. In the total patient series, the reciprocals of S-creatinine and S-cystatin C were numerically and, in males, significantly more closely correlated to GFR than the reciprocals of S-factor D. The reciprocals of beta 2-microglobulin showed a weaker correlation to GFR than those of the other three substances. The calculated glomerular elimination rates of creatinine, cystatin C and factor D were normally distributed, in contrast to those of beta 2-microglobulin. According to data presented so far, cystatin C seems to be the LMW protein of first choice when GFR is to be estimated by measuring the plasma concentration of a LMW protein.
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PMID:Serum concentration of cystatin C, factor D and beta 2-microglobulin as a measure of glomerular filtration rate. 391 36

The blood serum concentrations of creatinine and the low molecular weight proteins cystatin C, beta 2-microglobulin and retinol-binding protein were measured in 106 patients whose glomerular filtration rates were assessed by Cr-ethylenediaminetetraacetate (EDTA)-clearance determinations. The reciprocals of the serum concentrations of creatinine, cystatin C and beta 2-microglobulin were closely correlated to the Cr-EDTA-clearance (r = 0.73, 0.75 and 0.70, respectively) in contrast to the corresponding values for retinol-binding protein (r = 0.39). The calculated values of the glomerular elimination rate for creatinine and cystatin C were normally distributed in contrast to those for beta 2-microglobulin. The calculated glomerular elimination rate of cystatin C was not correlated to age, sex, type of disorder or disease activity. The results demonstrate that the serum level of cystatin C is a better measure of the glomerular filtration rate than the serum level of beta 2-microglobulin.
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PMID:The blood serum concentration of cystatin C (gamma-trace) as a measure of the glomerular filtration rate. 392 7

Enhanced nitrogen utilization occurs when adults with gastrointestinal disease are fed partially hydrolyzed proteins instead of isonitrogenous, isocaloric crystalline amino acids. A controlled trial was conducted to determine if this difference was also seen in malnourished stressed cancer patients and to gain an understanding of the underlying mechanism. Sixteen malnourished patients with head and neck cancer were prospectively randomized to either crystalline amino acid-glucose (CAA-G) or partially hydrolyzed protein-glucose (PHP-G) diets. Patients were fed via an enteral tube for 10 days starting on the second postoperative day. Blood SMA-6 and amino acid levels were measured on Days 1 and 10. Daily calorie counts and fluid balance were obtained. Daily 24-hr urine and stools were analyzed for total N during the last 5 days of the study period. The daily positive N balance with both diets was the same (CAA-G = +7.8 +/- 0.8 vs PHP-G = +8.2 +/- 1.0 g; mean +/- SE) and 3-methylhistidine:creatinine ratio did not differ. Patients on PHP-G diet gained significantly more weight (+0.5 vs - 1.5 kg; P less than 0.01) and had significantly higher serum albumin (3.2 +/- 0.2 vs 2.8 +/- 0.1 g/dl; P = 0.5) by the end of the 10th study day. Weight changes were not due to fluid retention: serum Na+, K+, creatinine and mean fluid intake for the two groups remained the same during the study period. A significantly greater rise in BUN occurred on the CAA-G diet (from 9.2 +/- 1.7 to 15.4 +/- 1.4 mg/dl; P less than 0.05) while BUN remained unchanged on the PHP-G diet.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of elemental diet on albumin and urea synthesis: comparison with partially hydrolyzed protein diet. 637 51

Serum levels of complement factor D, a low molecular weight (LMW) protein, were high and inversely correlated with glomerular filtration rate (GFR) determined in 19 patients with lupus glomerulonephritis (LGN). Factor D was significantly closer correlated with S-creatinine than were two other LMW proteins, beta 2-microglobulin and gamma-trace in 22 LGN patients. Close correlations between each of the LMW proteins and S-creatinine were found in patients with a non-inflammatory disorder, polycystic kidney disease. Slightly increased beta 2-microglobulin concentrations were found in 15 of 20 systemic lupus erythematosus (SLE) patients without renal involvement, while factor D and gamma-trace showed normal values in most of these patients. The findings imply that serum concentrations of complement factor D in SLE are mainly determined by the GFR.
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PMID:Serum level of complement factor D in systemic lupus erythematosus--an indicator of glomerular filtration rate. 638 50

The effects of total parenteral nutrition (TPN) in partially nephrectomized rats (n = 17) and sham-operated controls (n = 12) were evaluated and compared to the effect of low and high nitrogen oral diets (6% and 24% protein). TPN included fat (9 g/kg per day), high energy (1385 KJ/kg per day), and low nitrogen content (0.6 g N/kg per day, corresponding to 8% protein) either as essential amino acids (EAA) or as a mixture of essential and nonessential amino acids (CAA). The parenteral nutrition was administered intravenously via a permanent catheter continuously for 10 days. Most animals tolerated the treatment with no signs of overhydration or electrolyte imbalances. Uremic rats on TPN gained in weight similarly to control animals, whereas uremic rats given oral diets showed a lower weight increase. Both amino acid solutions promoted positive nitrogen balance and growth. Plasma urea dropped during TPN and low protein oral feeding in uremic and control rats, but not in the high protein-fed animals. Serum creatinine decreased with TPN but not with oral feeding in uremic rats. Albumin and hemoglobin levels were significantly reduced in all uremic rats irrespective of dietary treatment. The experimental model presented here could be useful for further studies on parenteral nutrition in uremia.
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PMID:Effects of total parenteral nutrition in rats with experimental chronic renal failure. 680 93

Serum cystatin C has been suggested as a new marker of GFR. For the introduction of this marker into clinical use a rapid and automated method is required. We have developed and validated an assay for serum cystatin C using latex particle-enhanced immunoturbidimetry. Intra- and inter-assay precision were < 3% and < 5% across the assay range. Analytical recovery was 93 +/- 3.8% and no lack of parallelism was demonstrated. Regression analysis of a method comparison with an enzyme-enhanced radial-immunodiffusion method, gave PETIA = 0.074 + 0.93 x SRID, r = 0.98, N = 100. Inter-assay precision profiles showed cystatin C was measured with two-fold better precision than creatinine on the same analyzer. Cystatin C measurement was neither interfered with by icterus nor by hemolysis. 1/cystatin C versus 1/creatinine concentrations gave r = 0.67, N = 469. Comparison of Cr EDTA GFR with 1/cystatin C and 1/creatinine gave r = 0.81 and 0.50, respectively, N = 206. Calculating diagnostic sensitivity for abnormal GFR showed cystatin C to be significantly (P < 0.05) more sensitive than creatinine (71.4 vs. 52.4%). Cystatin C measurement using PETIA technology can be automated on the same instruments used routinely for the measurement of creatinine and offers better analytical performance and probably improved clinical sensitivity as a screening test for early renal damage.
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PMID:Serum cystatin C measured by automated immunoassay: a more sensitive marker of changes in GFR than serum creatinine. 773 Nov 63

We describe a fully automated particle-enhanced turbidimetric assay for cystatin C in undiluted serum and EDTA-plasma. The throughput is 90 samples per hour and urgent samples can be analyzed in 7 min. The assay range (0.4-14.1 mg/L) covers the concentration range in health and disease. The within- and between-run imprecision is 0.9% and 2.2%, respectively. Analytical recovery of additions of recombinant cystatin C averaged 98%. Rheumatoid factors (< or = 323,000 IU/L), bilirubin (< or = 150 mumol/L), hemoglobin (< or = 1.2 g/L), and triglycerides (< or = 8.5 mmol/L) do not interfere in the assay. In view of the superior (by ROC analysis) diagnostic accuracy of serum concentrations of cystatin C for reduced glomerular filtration rate (GFR) in comparison with creatinine, cystatin C seems an attractive alternative to creatinine for estimation of GFR.
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PMID:Serum cystatin C, determined by a rapid, automated particle-enhanced turbidimetric method, is a better marker than serum creatinine for glomerular filtration rate. 792 73

We developed a sandwich enzyme immunoassay for determining cystatin C in serum by using commercially available antibodies. We optimized each assay step (e.g., concentrations of coating rabbit anti-human cystatin C antibodies and horseradish peroxidase-conjugated antibodies) and studied the binding kinetics of antigen and antibodies. The within-assay CV was < 5%, the between-assay CV was 8.8%, the detection limit was 0.9 microgram/L, and the assay can be performed within 2 h. Cystatin C concentrations in sera from men were significantly higher than in women (mean and SD: 2.14 +/- 0.31 vs 1.78 +/- 0.26 mg/L). We studied the cystatin C concentrations in sera of 31 outpatients with suspected kidney damages to characterize the behavior of this low-M(r) protein as a possible indicator for estimating the glomerular filtration rate. The correlation with the values obtained by a standard isotopic method involving 99mTc-diethylenetriaminopentaacetic acid was rs = -0.89. The diagnostic sensitivity of cystatin C was 88.2% of that of the standard isotope clearance method and better than those of the conventional serum indicators of reduced kidney function, beta 2-microglobulin (64.7%) and creatinine (52.9%).
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PMID:Sandwich enzyme immunoassay of cystatin C in serum with commercially available antibodies. 837 65


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