Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kidney function can be assessed by a number of methods. The urinary excretion of enzymes, in particular N-acetyl-beta-D-glucosaminidase (NAG), is considered a relatively simple, cheap, fast and non-invasive method in the detection and follow-up of renal tubular function under various conditions. The determination of urinary NAG provides a very sensitive and reliable indicator of renal damage, such as injury or dysfunction due to diabetes mellitus, nephrotic syndrome, inflammation, vesicoureteral reflux, urinary tract infection, hypercalciuria, urolithiasis, nephrocalcinosis, perinatal asphyxia, hypoxia, hypertension, heavy metals poisoning, treatment with aminoglycosides, valproate, or other nephrotoxic drugs. This paper gives an overview of the current use of urinary NAG in the detection of renal injury.
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PMID:The diagnostic role of urinary N-acetyl-beta-D-glucosaminidase (NAG) activity in the detection of renal tubular impairment. 1625 16

Nephrologists and urologists are frequently faced with patients with asymptomatic isolated microhaematuria (AIMH). This entity is defined as the presence of more than 5 red cells/uL in the sediment of first morning urine, in the absence of symptoms by the urinary tract and in the absence of proteinuria. From 201 children who were referred on the clinical examinations on the Pediatric Clinic in Sarajevo under the diagnosis haematuria in period from 01/01/1997 until 31/08/2002, 87 had AIMH. Age of life was from 0 to 16 years (mean 8 years). Fourteen children (16.1%) had a hypercalciuria, 10 (11.5%) had a state after purpura Henoch-Schonlein nad scarlatine, while 6 (6.9%) had glomerulopathy. Five children (5.7%) had anomalies of urinary system, 5 (5.7%) had evidence of nephrolithiasis, while 4 (4.6%) had asymptomatic urinary tract infection. Cause out of urinary system was found in 29 children (33.3%) and for 14 children (16.1%) etiology remained unknown. Transient microhaematuria was noted in 43 children (49.4%), recurrent in 37 (42.5%) and persistent in 7 (8.1%). Renal biopsy was performed in 5 children (5.7%) because of indications of glomerular disease and all of them had glomerular lesions. Sixty nine children of these 87 were followed up from 2 to 11 years (mean period of 3 years) and none of them developed hypertension or renal impairment. Most patients who have AIMH do not have clinically significant glomerular pathology and they don't need renal biopsy, but only periodic follow up. Any degree of proteinuria accompanying haematuria should be fully investigated, as proteinuria is often a sign of serious renal disease.
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PMID:[Asymptomatic isolated microhaematuria--a reason for concern?]. 1642 27

Multiple cationic channels with variable selectivity for Ca(2+) , K(+) and Na(+) have been identified in smooth muscle cells (SMC) as well as non-excitable cells. They control Ca(2+) store refilling and depletion, G-protein-mediated receptor activation, apoptosis and cell growth, membrane potential, intracellular pH, oxidative stress, phospholipid signaling, and other critical cell functions. A novel superfamily of divalent cation channels has been recently characterized as highly conserved heterotetramer homologues of Drosophila transient receptor potential (TRP). At least 50 members of seven major TRP channel families have been identified to date. The involvement of TRP in store-operated Ca(2+) - gating has been demonstrated in various tissues, along with intestinal and renal epithelial cell Ca(2+) and Mg(2+) transport, indicating a role in total body homeostasis of divalent cations. TRPV5-null mice display phenotypic defects including hypercalciuria and impaired bone mineral density. TRPP2 or polycystin 2 (PC2), encoded by the PKD2 gene, is an integral protein of epithelial cilia whose mutation is associated with autosomal dominant polycystic kidney disease (ADPKD). A TRPP1 (polycystin 1)-PC2 channel complex is actually implicated in the transduction of environmental signals (i.e. luminal tubular fluid flow and composition) into cellular events, such as epithelial cell growth. TRP channels can eventually play a role in the pathogenesis of arterial hypertension via direct effects on vascular smooth muscle contraction, renal blood flow, glomerular hemodynamics and the tubular handling of Ca(2+) and electrolytes.
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PMID:Transient receptor potential channels in the kidney: calcium signaling, transport and beyond. 1652 21

Compared with the Stone Age diet, the modern human diet is both excessive in NaCl and deficient in fruits and vegetables which are rich in K+ and HCO3- -yielding organates like citrate. With the modern diet, the K+/Na+ ratio and the HCO3-/Cl- ratio have both become reversed. Yet, the biologic machinery that evolved to process these dietary electrolytes remains largely unchanged, genetically fixed in Paleolithic time. Thus, the electrolytic mix of the modern diet is profoundly mismatched to its processing machinery. Dietary potassium modulates both the pressor and hypercalciuric effects of the modern dietary excess of NaCl. A marginally deficient dietary intake of potassium amplifies both of these effects, and both effects are dose-dependently attenuated and may be abolished either with dietary potassium or supplemental KHCO3. The pathogenic effects of a dietary deficiency of potassium amplify, and are amplified by, those of a dietary excess of NaCl and in some instances a dietary deficiency of bicarbonate precursors. Thus, in those ingesting the modern diet, it may not be possible to discern which of these dietary electrolytic dislocations is most determining of salt-sensitive blood pressure and hypercalciuria, and the hypertension, kidney stones, and osteoporosis they may engender. Obviously abnormal plasma electrolyte concentrations rarely characterize these dietary electrolytic dislocations, and when either dietary potassium or supplemental KHCO3 corrects the pressor and hypercalciuric effects of these dislocations, the plasma concentrations of sodium, potassium, bicarbonate and chloride change little and remain well within the normal range.
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PMID:Relationship and interaction between sodium and potassium. 1677 38

Increased urinary calcium excretion commonly is found in patients with hypertension and kidney stone disease (KSD). This study investigated the aggregation of hypertension and KSD in families of patients with KSD and hypercalciuria and explored whether obesity, excessive weight gain, and diabetes, commonly related conditions, also aggregate in these families. Consecutive patients with KSD, aged 18 to 50 yr, were recruited from a population-based Kidney Stone Center, and a 24-h urine sample was collected. The first-degree relatives of eligible patients (n = 333) and their spouse were interviewed by telephone to collect demographic and health information. Familial aggregation was assessed using generalized estimating equations. Multivariate-adjusted odds ratios (OR) revealed significant associations between hypercalciuria in patients and hypertension (OR 2.9; 95% confidence interval 1.4 to 6.2) and KSD (OR 1.9; 95% confidence interval 1.03 to 3.5) in first-degree relatives, specifically in siblings. No significant associations were found in parents or spouses or in patients with hyperuricosuria. Similarly, no aggregation with other conditions was observed. In an independent study of siblings of hypercalciuric patients with KSD, the adjusted mean fasting urinary calcium/creatinine ratio was significantly higher in the hypertensive siblings compared with normotensive siblings (0.60 +/- 0.32 versus 0.46 +/- 0.28 mmol/mmol; P < 0.05), and both sibling groups had significantly higher values than the unselected study participants (P < 0.001). Urinary sodium/creatinine and uric acid/creatinine ratios were not different among the groups. Although an environmental effect cannot be excluded fully, our findings suggest that the disturbance in calcium metabolism in hypertension and KSD has a genetic basis.
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PMID:High urinary calcium excretion and genetic susceptibility to hypertension and kidney stone disease. 1685 17

The mechanisms that govern homeostasis of complex systems have been elusive but can be illuminated by mutations that disrupt system behavior. Mutations in the gene encoding the kinase WNK4 cause pseudohypoaldosteronism type II (PHAII), a syndrome featuring hypertension and hyperkalemia. We show that physiology in mice transgenic for genomic segments harboring wild-type (TgWnk4(WT)) or PHAII mutant (TgWnk4(PHAII)) Wnk4 is changed in opposite directions: TgWnk4(PHAII) mice have higher blood pressure, hyperkalemia, hypercalciuria and marked hyperplasia of the distal convoluted tubule (DCT), whereas the opposite is true in TgWnk4(WT) mice. Genetic deficiency for the Na-Cl cotransporter of the DCT (NCC) reverses phenotypes seen in TgWnk4(PHAII) mice, demonstrating that the effects of the PHAII mutation are due to altered NCC activity. These findings establish that Wnk4 is a molecular switch that regulates the balance between NaCl reabsorption and K+ secretion by altering the mass and function of the DCT through its effect on NCC.
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PMID:Wnk4 controls blood pressure and potassium homeostasis via regulation of mass and activity of the distal convoluted tubule. 1700 64

The epithelial Ca(2+) channel TRPV5 serves as a gatekeeper for active Ca(2+) reabsorption in the distal convoluted tubule and connecting tubule of the kidney. WNK4, a protein serine/threonine kinase with gene mutations that cause familial hyperkalemic hypertension (FHH), including a subtype with hypercalciuria, is also localized in the distal tubule of the nephron. To understand the role of WNK4 in modulation of Ca(2+) reabsorption, we evaluated the effect of WNK4 on TRPV5-mediated Ca(2+) transport in Xenopus laevis oocytes. Coexpression of TRPV5 with WNK4 resulted in a twofold increase in TRPV5-mediated Ca(2+) uptake. The increase in Ca(2+) uptake was due to the increase in surface expression of TRPV5. When the thiazide-sensitive Na(+)-Cl(-) cotransporter NCC was coexpressed, the effect of WNK4 on TRPV5 was weakened by NCC in a dose-dependent manner. Although the WNK4 disease-causing mutants E562K, D564A, Q565E, and R1185C retained their ability to upregulate TRPV5, the blocking effect of NCC was further strengthened when wild-type WNK4 was replaced by the Q565E mutant, which causes FHH with hypercalciuria. We conclude that WNK4 positively regulates TRPV5-mediated Ca(2+) transport and that the inhibitory effect of NCC on this process may be involved in the pathogenesis of hypercalciuria of FHH caused by gene mutation in WNK4.
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PMID:WNK4 enhances TRPV5-mediated calcium transport: potential role in hypercalciuria of familial hyperkalemic hypertension caused by gene mutation of WNK4. 1701 46

Inherited tubular disorders associated with metabolic alkalosis are caused by several gene mutations encoding different tubular transporters responsible for NaCl renal handling. Body volume and renin-angiotensin-aldosterone system status are determined by NaCl reabsorption in the distal nephron. Two common hallmarks in affected individuals: hypokalemia and normal / high blood pressure, support the differential diagnosis. Bartter's syndrome, characterized by hypokalemia and normal blood pressure, is a heterogenic disease caused by the loss of function of SLC12A1 (type 1), KCNJ1 (type 2), CLCNKB (type 3), or BSND genes (type 4). As a result, patients present with renal salt wasting and hypercalciuria. Gitelman's syndrome is caused by the loss of funcion of the SLC12A3 gene and may resemble Bartter's syndrome, though is associated with the very low urinary calcium. Liddle's syndrome, also with similar phenotype but with hypertension, is produced by the gain of function of the SNCC1B or SNCC1G genes, and must be distinguished from other entities of inherited hypertension such as Apparently Mineralocorticoid Excess, of glucocorticoid remediable hypertension.
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PMID:Inherited renal tubulopathies associated with metabolic alkalosis: effects on blood pressure. 1727 79

Most of the published studies evaluating renal prognosis of children born very preterm found asymptomatic abnormalities (blood pressure, glomerular filtration rate GFR, hypercalciuria, decreased renal size, microalbuminuria...) during childhood or early adulthood. The objective of this study was to assess renal function (inulin clearance) in a prospective single-center cohort of children born preterm between 1998 and 2001 (< 30 GW,<1000 g) and to identify neonatal risk factors for renal abnormalities during childhood. Fifty children were included in the final part of the study. At a mean age of 7.6 years, no patient had arterial hypertension or chronic kidney disease, but mean centile for diastolic blood pressure was higher than expected and ultrasounds revealed small-sized kidneys compared to controls. The average GFR was 112 ml/min per 1.73 m(2) (91-158). Two children had microalbuminuria, two had hypercalciuria and one had nephrocalcinosis. Children with intra- or extra-uterine growth retardation had an impaired GFR compared to children with appropriate pre- and post-natal growth (107 vs. 110 vs. 125 ml/min per 1.73 m(2), p<0.05). Children with bronchopulmonary dysplasia had a significant higher microalbuminuria. In conclusion, findings of borderline blood pressure and reduced kidney size in children born preterm can be regarded as markers of reduced nephron number. Long term renal follow-up (blood pressure, serum creatinine, urine albumin / creatinine ratio) should be performed in all children born very preterm, with an early referring when abnormalities are highlighted.
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PMID:[Long term renal outcome of children born preterm: a regular follow-up is needed]. 1983 67

Developmental programming of hypertension, induced by maternal protein restriction, is associated with enhanced urinary excretion of sodium and calcium in the rat. Although calcium and magnesium are reabsorbed via different pathways, renal calcium excretion often parallels magnesium output. Accordingly, the aim of the current study was to assess magnesium handling in rats exposed to a low-protein (LP) diet in utero. Wistar rats were fed a control (18%) or LP (9%) diet throughout pregnancy; offspring were weaned onto standard rat chow and studied at 4 weeks of age. Renal clearance measurements were made in both volume expanded and euvolaemic anaesthetised rats; 24-hour magnesium turnover was also assessed in conscious animals. Plasma and total body magnesium content were measured. Total (U(Mg)V) and fractional excretion (FE(Mg)) of magnesium did not differ between control and LP rats under any of the experimental conditions. Neither plasma nor total body magnesium content differed between control and LP rats. Thus the hypercalciuria of LP rats is not mirrored by an increase in renal magnesium excretion. These data suggest that renal magnesium handling is not affected by developmental programming.
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PMID:Renal magnesium handling is not subject to developmental programming. 2035 95


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