Nephrocalcinosis: A condition characterized by calcification of the renal tissue itself. It is usually seen in distal RENAL TUBULAR ACIDOSIS with calcium deposition in the DISTAL KIDNEY TUBULES and the surrounding interstitium. Nephrocalcinosis causes RENAL INSUFFICIENCY.Hypercalciuria: Excretion of abnormally high level of CALCIUM in the URINE, greater than 4 mg/kg/day.Renal Tubular Transport, Inborn Errors: Genetic defects in the selective or non-selective transport functions of the KIDNEY TUBULES.Claudins: A large family of transmembrane proteins found in TIGHT JUNCTIONS. They take part in the formation of paracellular barriers and pores that regulate paracellular permeability.Hyperoxaluria: Excretion of an excessive amount of OXALATES in the urine.Medullary Sponge Kidney: A non-hereditary KIDNEY disorder characterized by the abnormally dilated (ECTASIA) medullary and inner papillary portions of the collecting ducts. These collecting ducts usually contain CYSTS or DIVERTICULA filled with jelly-like material or small calculi (KIDNEY STONES) leading to infections or obstruction. It should be distinguished from congenital or hereditary POLYCYSTIC KIDNEY DISEASES.Acidosis, Renal Tubular: A group of genetic disorders of the KIDNEY TUBULES characterized by the accumulation of metabolically produced acids with elevated plasma chloride, hyperchloremic metabolic ACIDOSIS. Defective renal acidification of URINE (proximal tubules) or low renal acid excretion (distal tubules) can lead to complications such as HYPOKALEMIA, hypercalcinuria with NEPHROLITHIASIS and NEPHROCALCINOSIS, and RICKETS.Kidney Calculi: Stones in the KIDNEY, usually formed in the urine-collecting area of the kidney (KIDNEY PELVIS). Their sizes vary and most contains CALCIUM OXALATE.Hypophosphatemia, Familial: An inherited condition of abnormally low serum levels of PHOSPHATES (below 1 mg/liter) which can occur in a number of genetic diseases with defective reabsorption of inorganic phosphorus by the PROXIMAL RENAL TUBULES. This leads to phosphaturia, HYPOPHOSPHATEMIA, and disturbances of cellular and organ functions such as those in X-LINKED HYPOPHOSPHATEMIC RICKETS; OSTEOMALACIA; and FANCONI SYNDROME.Bartter Syndrome: A group of disorders caused by defective salt reabsorption in the ascending LOOP OF HENLE. It is characterized by severe salt-wasting, HYPOKALEMIA; HYPERCALCIURIA; metabolic ALKALOSIS, and hyper-reninemic HYPERALDOSTERONISM without HYPERTENSION. There are several subtypes including ones due to mutations in the renal specific SODIUM-POTASSIUM-CHLORIDE SYMPORTERS.Hyperoxaluria, Primary: A genetic disorder characterized by excretion of large amounts of OXALATES in urine; NEPHROLITHIASIS; NEPHROCALCINOSIS; early onset of RENAL FAILURE; and often a generalized deposit of CALCIUM OXALATE. There are subtypes classified by the enzyme defects in glyoxylate metabolism.Nephrolithiasis: Formation of stones in the KIDNEY.Magnesium Deficiency: A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. (Harrison's Principles of Internal Medicine, 12th ed, p1936)Phosphorus: A non-metal element that has the atomic symbol P, atomic number 15, and atomic weight 31. It is an essential element that takes part in a broad variety of biochemical reactions.Amelogenesis Imperfecta: A clinically and genetically heterogeneous group of hereditary conditions characterized by malformed DENTAL ENAMEL, usually involving DENTAL ENAMEL HYPOPLASIA and/or TOOTH HYPOMINERALIZATION.Calcium Oxalate: The calcium salt of oxalic acid, occurring in the urine as crystals and in certain calculi.Fanconi Syndrome: A hereditary or acquired form of generalized dysfunction of the PROXIMAL KIDNEY TUBULE without primary involvement of the KIDNEY GLOMERULUS. It is usually characterized by the tubular wasting of nutrients and salts (GLUCOSE; AMINO ACIDS; PHOSPHATES; and BICARBONATES) resulting in HYPOKALEMIA; ACIDOSIS; HYPERCALCIURIA; and PROTEINURIA.Phosphates: Inorganic salts of phosphoric acid.Urolithiasis: Formation of stones in any part of the URINARY TRACT, usually in the KIDNEY; URINARY BLADDER; or the URETER.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Gitelman Syndrome: An inherited renal disorder characterized by defective NaCl reabsorption in the convoluted DISTAL KIDNEY TUBULE leading to HYPOKALEMIA. In contrast with BARTTER SYNDROME, Gitelman syndrome includes hypomagnesemia and normocalcemic hypocalciuria, and is caused by mutations in the thiazide-sensitive SODIUM-POTASSIUM-CHLORIDE SYMPORTERS.Water-Electrolyte Imbalance: Disturbances in the body's WATER-ELECTROLYTE BALANCE.Oxalates: Derivatives of OXALIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are derived from the ethanedioic acid structure.Familial Hypophosphatemic Rickets: A hereditary disorder characterized by HYPOPHOSPHATEMIA; RICKETS; OSTEOMALACIA; renal defects in phosphate reabsorption and vitamin D metabolism; and growth retardation. Autosomal and X-linked dominant and recessive variants have been reported.Phosphorus, Dietary: Phosphorus used in foods or obtained from food. This element is a major intracellular component which plays an important role in many biochemical pathways relating to normal physiological functions. High concentrations of dietary phosphorus can cause nephrocalcinosis which is associated with impaired kidney function. Low concentrations of dietary phosphorus cause an increase in calcitriol in the blood and osteoporosis.Sodium-Phosphate Cotransporter Proteins, Type IIc: A non-electrogenic sodium-dependent phosphate transporter. It is found primarily in apical membranes of PROXIMAL RENAL TUBULES.Calcium Metabolism Disorders: Disorders in the processing of calcium in the body: its absorption, transport, storage, and utilization.Hypoparathyroidism: A condition caused by a deficiency of PARATHYROID HORMONE (or PTH). It is characterized by HYPOCALCEMIA and hyperphosphatemia. Hypocalcemia leads to TETANY. The acquired form is due to removal or injuries to the PARATHYROID GLANDS. The congenital form is due to mutations of genes, such as TBX1; (see DIGEORGE SYNDROME); CASR encoding CALCIUM-SENSING RECEPTOR; or PTH encoding parathyroid hormone.Kidney Medulla: The internal portion of the kidney, consisting of striated conical masses, the renal pyramids, whose bases are adjacent to the cortex and whose apices form prominent papillae projecting into the lumen of the minor calyces.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
NephrocalcinosisUrinary calcium: Urinary calcium is calcium in the urine. It is termed -calcuria or -calciuria as a suffix.HyperoxaluriaRenal cystDistal renal tubular acidosis: Distal renal tubular acidosis (dRTA) or Type 1 Renal tubular acidosis (RTA) is the classical form of RTA, being the first described. Distal RTA is characterized by a failure of acid secretion by the alpha intercalated cells of the cortical collecting duct of the distal nephron.Renal stone formation in space: Renal stone formation and passage during space flight can potentially pose a severe risk to crew member health and safety and could affect mission outcome. While the renal stones are routinely and successfully treated on Earth, the occurrence of these during space flight can prove to be problematic.ROMK: The renal outer medullary potassium channel (ROMK) is an ATP-dependent potassium channel (Kir1.1) that transports potassium out of cells.Magnesium (pharmaceutical preparation): Magnesium, as a pharmaceutical preparation, is used to treat conditions including magnesium deficiency and hypomagnesemia, as well as eclampsia. Magnesium is important to health.Phosphorus deficiency: Phosphorus deficiency is a plant disorder associated with insufficient supply of phosphorus. Phosphorus refers here to salts of phosphates (PO43−), monohydrogen phosphate (HPO42−), and dihydrogen phosphate (H2PO4−).Amelogenesis imperfectaHerniaria hirsuta: Herniaria hirsuta is a species of flowering plant in the pink family known by the common name hairy rupturewort. It is native to Eurasia and North Africa, and it is known on other continents, including North America, as an introduced species.Organic anion transporter 1Sodium hexametaphosphateUrolithiasisKidney: The kidneys are bean-shaped organs that serve several essential regulatory roles in vertebrates. They remove excess organic molecules from the blood, and it is by this action that their best-known function is performed: the removal of waste products of metabolism.Gitelman syndromeWater-electrolyte imbalanceSodium oxalate: http://chem.sis.Monosodium phosphateCalcium metabolism: Calcium metabolism refers to all the movements (and how they are regulated) of calcium atoms and ions into and out of various body compartments, such as the gut, the blood plasma, the interstitial fluids which bathe the cells in the body, the intracellular fluids, and bone. An important aspect, or component, of calcium metabolism is plasma calcium homeostasis, which describes the mechanisms whereby the concentration of calcium ions in the blood plasma is kept within very narrow limits.HypoparathyroidismRenal medullaCalcium signaling: Calcium ions are important for cellular signalling, as once they enter the cytosol of the cytoplasm they exert allosteric regulatory effects on many enzymes and proteins. Calcium can act in signal transduction resulting from activation of ion channels or as a second messenger caused by indirect signal transduction pathways such as G protein-coupled receptors.
(1/173) Renal biopsy in the milk-alkali syndrome.
In milk-alkali syndrome the degree of renal impairment varies greatly. Few reports have been published describing structural changes on renal biopsy. In three illustrative cases, impairment of renal function was related to morphological changes shown on percutaneous biopsy. Milk-alkali syndrome should be considered as a cause of renal dysfunction in patients with a long history of dyspensia. (+info)
(2/173) Differential effects of T- and L-type calcium antagonists on glomerular dynamics in spontaneously hypertensive rats.
To determine whether there is a difference in the effects of T- and L-type calcium antagonists on systemic, renal, and glomerular hemodynamics, the pathological changes of N(G)-nitro-L-arginine methyl ester (L-NAME)-exacerbated nephrosclerosis and clinical alterations were investigated in spontaneously hypertensive rats (SHR). Seven groups of 17-week-old male SHRs were studied: Group 1, control; Group 2, mibefradil, 50 mg. kg(-1). d(-1); Group 3, L-NAME in drinking water, 50 mg/L; Group 4, L-NAME (50 mg/L) plus mibefradil (50 mg. kg(-1). d(-1)); Group 5, L-NAME (50 mg/L) plus amlodipine (10 mg. kg(-1). d(-1)); Group 6 and 7, L-NAME (50 mg/L) for 3 weeks followed by mibefradil (50 mg. kg(-1). d(-1)) or amlodipine (10 mg. kg(-1). d(-1)), respectively, for the subsequent 3 weeks. Both the T- and L-channel calcium antagonists similarly reduced mean arterial pressure and total peripheral resistance index. These changes were associated with significant decreases in afferent and efferent glomerular arteriolar resistances and the ultrafiltration coefficient (P<0.01). Furthermore, the histopathological glomerular and arterial injury scores and urinary protein excretion were also significantly improved (P<0.01), and left ventricular and aortic masses were significantly diminished in all treated groups. Both drugs, mibefradil and amlodipine, had effects of increasing the single-nephron glomerular filtration ratio (SNGFR), and single-nephron plasma flow (SNPF), and of reducing glomerular afferent arteriolar resistance and urinary protein excretion. Thus, the T-type (mibefradil) and L-type (amlodipine) calcium antagonists each prevented and reversed the pathophysiological alterations of L-NAME-exacerbated hypertensive nephrosclerosis in SHR. The T-type calcium antagonist (mibefradil) seemed to have been more effective than the L-type amlodipine antagonist and it produced a greater reduction in afferent arteriolar resistance while preserving SNGFR. (+info)
(3/173) Vitamin D3-induced proliferative lesions in the rat adrenal medulla.
Adrenal medullary hyperplasia and pheochromocytomas are induced in rats by a variety of non-genotoxic agents, and we have hypothesized that these agents induce lesions indirectly by stimulating chromaffin cell proliferation. Vitamin D3, which has not been previously associated with adrenal medullary proliferative lesions, is the most potent in vivo stimulus to chromaffin cell proliferation yet identified. The present investigation utilized the vitamin D3 model to prospectively test the relationship between mitogenicity and focal proliferative lesions in the adrenal medulla and to determine early events in the pathogenesis of these lesions. Charles River Crl:CD BR rats were treated with 0; 5000; 10,000; or 20,000 IU/kg/day of vitamin D3 in corn oil (5 ml/kg) by oral intubation. Rats were killed after 4, 8, 12, or 26 weeks of treatment, following a final week of labeling with bromodeoxyuridine (BrdU) using a mini-pump. Adrenal sections were double-stained for BrdU and phenylethanolamine-N-methyl transferase (PNMT) to discriminate epinephrine (E) from norepinephrine (NE) cells or for vesicular acetylcholine transporter (VAchT) to identify cholinergic nerve endings. Vitamin D3 caused a 4-5-fold increase in BrdU labeling at week 4, diminishing to a 2-fold increase by week 26. An initial preponderance of labeled E cells gave way to a preponderance of labeled NE cells. By week 26, 17/19 (89%) animals receiving the 2 highest doses of vitamin D3 had focal adrenal medullary proliferative lesions, in contrast to an absence of lesions in control rats. The lesions encompassed a spectrum including BrdU-labeled "hot spots" not readily visible on H and E sections, hyperplastic nodules, and pheochromocytomas. Lesions were usually multicentric, bilateral, and peripheral in location, and almost all were PNMT-negative. The lesions were not cholinergically innervated, suggesting autonomous proliferation. Hot spots, hyperplastic nodules, and pheochromocytomas appear to represent a continuum rather than separate entities. Their development might involve selective responses of chromaffin cell subsets to mitogenic signals, influenced by both innervation and corticomedullary interactions. A number of non-genotoxic compounds that induce pheochromocytomas in rats are known to affect calcium homeostasis. The results of this study provide further evidence to support the hypothesis that altered calcium homeostasis is indirectly involved in the pathogenesis of pheochromocytomas, via effects on chromaffin cell proliferation. (+info)
(4/173) Effects of low animal protein or high-fiber diets on urine composition in calcium nephrolithiasis.
BACKGROUND: The purpose of this article is to evaluate the impact of low protein and high fiber intakes on risk factors of stone recurrence in idiopathic calcium stone formers (ICSFs). METHODS: Ninety-six ICSFs were randomly assigned a low animal protein diet (< 10% of total energy), a high-fiber diet (> 25 g/day), or a usual diet (control group); all patients were recommended to increase their fluid intake. Their daily urine compositions were analyzed at baseline and at four months. Compliance with dietary recommendations was checked by validated food frequency questionnaires. Compliance with total and animal protein intakes was assessed by 24-hour urea and sulfate outputs, respectively. The nutritional intervention (oral instructions, written leaflet, phoning) and food assessment were carried out by a research dietitian. RESULTS: At baseline, diets and the daily urine composition did not differ between the three groups. At four months, while diets differed significantly, the 24-hour output of calcium and oxalate did not differ significantly within and between groups after adjustment for potential confounders (age, sex, and personal and family history of calcium stones) and baseline values. However, as many as 12 out of 31 ICSFs (95% CI, 22 to 58%) assigned to a low animal protein diet achieved a reduction in the urine urea excretion rate of more than 50 mmol/day and also exhibited a significant decrease in urinary calcium excretion that averaged 1.8 mmol/day. A significant correlation between urea and calcium outputs was observed only among patients with hypercalciuria. CONCLUSIONS: These results show that only ICSFs who markedly decrease their animal protein intake, especially those with hypercalciuria, can expect to benefit from dietary recommendations. (+info)
(5/173) Urinary oxalate excretion in urolithiasis and nephrocalcinosis.
AIMS: To investigate urinary oxalate excretion in children with urolithiasis and/or nephrocalcinosis and to classify hyperoxaluria (HyOx). METHODS: A total of 106 patients were screened. In those in whom the oxalate: creatinine ratio was increased, 24 hour urinary oxalate excretion was measured. Liver biopsy and/or genomic analysis was performed if primary hyperoxaluria (PH) was suspected. Stool specimens were examined for Oxalobacter formigenes in HyOx not related to PH type 1 or 2 (PH1, PH2) and in controls. RESULTS: A total of 21 patients screened had HyOx (>0.5 mmol/24 h per 1.73 m(2)); they were classified into five groups. Eleven had PH (PH1 in nine and neither PH1 nor PH2 in two). Six had secondary HyOx: two enteric and four dietary. Four could not be classified. Seven patients had concomitant hypercalciuria. Only one of 12 patients was colonised with O formigenes compared to six of 13 controls. CONCLUSIONS: HyOx is an important risk factor for urolithiasis and nephrocalcinosis in children, and can coexist with hypercalciuria. A novel type of PH is proposed. Absence of O formigenes may contribute to HyOx not related to PH1. (+info)
(6/173) Hypomagnesaemia-hypercalciuria-nephrocalcinosis: a report of nine cases and a review.
BACKGROUND: The cardinal characteristics of primary hypomagnesaemia-hypercalciuria-nephrocalcinosis include renal magnesium wasting, marked hypercalciuria, renal stones, nephrocalcinosis, a tendency towards chronic renal insufficiency and sometimes even ocular abnormalities or hearing impairment. METHODS: As very few patients with this syndrome have been described, we provide information on nine patients on follow-up at our institutions and review the 42 cases reported in the literature (33 females and 18 males). RESULTS: Urinary tract infections, polyuria-polydipsia, renal stones and tetanic convulsions were the main clinical findings at diagnosis. The clinical course was highly variable; renal failure was often reported. The concomitant occurrence of ocular involvement or hearing impairment was reported in a large subset of patients. Parental consanguinity was noted in some families. CONCLUSIONS: The results indicate an autosomal recessive inheritance. The diagnosis of primary hypomagnesaemia-hypercalciuria-nephrocalcinosis deserves consideration in any patient with nephrocalcinosis and hypercalciuria. (+info)
(7/173) Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis maps to chromosome 3q27 and is associated with mutations in the PCLN-1 gene.
Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC, MIM 248250) is a complex renal tubular disorder characterised by hypomagnesaemia, hypercalciuria, advanced nephrocalcinosis, hyposthenuria and progressive renal failure. The mode of inheritance is autosomal recessive. A primary defect in the reabsorption of magnesium in the medullary thick ascending limb of the loop of Henle (mTAL) has been proposed to be essential in FHHNC pathophysiology. To identify the underlying genetic defect we performed linkage analysis in eight families, including three with consanguineous marriages. We found linkage to microsatellite markers on chromosome 3q27 with a maximum two-point lod score (Zmax) of 5.208 for D3S3530 without evidence for genetic heterogeneity. Haplotype analysis revealed crucial recombination events reducing the critical interval to 6.6cM. Recently, mutations in the gene PCLN-1, mapping to 3q27 and coding for paracellin-1, were identified by Simon et al (1999) as the underlying genetic defect in FHHNC. Paracellin-1 represents a renal tight junction protein predominantly expressed in the TAL. Mutational analysis in our patient cohort revealed eight different mutations in the PCLN-1 gene, within six novel mutations. In seven of 13 mutant alleles we detected a Leu151 substitution without evidence for a founder effect. Leu151 is a residue of the first extracellular loop of paracellin-1, the part of the protein expected to bridge the intercellular space and to be important for paracellular conductance. This study confirms the implication of paracellin-1 defects in FHHNC and points to a predominant role of this protein in the paracellular reabsorption of divalent cations in the TAL. (+info)
(8/173) Growth and metabolic disturbances in a patient with total parenteral nutrition: a case of hypercalciuric hypercalcemia.
Hypercalciuria is a common side effect during total parenteral nutrition (TPN). We report a patient with long-term TPN, who demonstrated hypercalciuria, hypercalcemia and growth retardation. The patient is a six-year-old Japanese girl with Hirschsprung disease (jejunal agangliosis). Jejunostomy was performed at one-month old and since then her nutrition has depended mostly on TPN. When she was 3 years old, continuous TPN was switched to cyclic TPN (on TPN for 11 hrs and off TPN for 13 hrs). The urinary calcium level has been elevated (Ca/Cre ratio, 1.0) since 3 months of age, whereas serum calcium levels stayed within normal range for a while. The serum calcium levels started to elevate to 12 to approximately 13 mg/dl when she was 3 years and 8 months old. She showed growth retardation (height SD score was -4.2SD when she was 5 years and 8 months old) and deteriorated renal tubular function with renal glycosuria, elevated beta 2-microglobulin (beta2-MG) and N-acetyl-beta-D-glucosaminidase. She was referred to our division for the investigation and treatment of growth disturbance and Ca metabolism. Her bone age was delayed (BA/CA 0.62) and serum IGF-I level was decreased but her GH response to provocation test was normal. Bilateral nephrocalcinosis was revealed by renal echogram and CT scan. By reducing calcium content in TPN solution, the serum and urinary calcium levels could be maintained within normal range and her renal function and growth velocity was improved. (+info)