Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0392525 (nephrolithiasis)
 2,669 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Low levels of red blood cell (RBC) carbonic anhydrase (CA) activity in hemoglobin-free hemolyzate (HFH) were found in 2 children with nephrolithiasis when compared to age-matched controls. The lowest levels were consistently found over a two year period in a 6 1/2 year old boy (U.P.) whose renal calculi contained uric acid, ammonia, calcium carbonate and oxalate. His RBC CA values ranged from 1.4-2.7 U/g Hb compared with levels of 3.9-5.3 U/g Hb in control subjects. Statistical comparisons of the mean values for U.P., 2.06 U/g Hb, and his age-matched control subjects, 4.46 U/g Hb, revealed a significant difference (P = less than 0.001). Similar reductions in RBC CA activity were found in his father--2.0 and 2.1 U/g Hb compared with 3.3 and 3.9 U/g Hb in adult controls. HFH CA activity was not decreased in the mother or sister. Polyacrylamide gel electrophoresis of HFH from 4 of the children and the father of U.P. was abnormal. However, this abnormal electrophoretic pattern could only be demonstrated when the gel was run for 120 minutes and not when it was run for 80 or 160 minutes. We have identified a patient and his father with low levels of RBC CA activity.
 ...
PMID:Reduced red blood cell carbonic anhydrase activity in a patient with nephrolithiasis. 10 68

Chronic metabolic acidosis results in metabolic bone disease, calcium nephrolithiasis, and growth retardation. The pathogenesis of each of these sequelae is poorly understood in humans. We therefore investigated the effects of chronic extrarenal metabolic acidosis on the regulation of 1,25-(OH)2D, parathyroid hormone, calcium, and phosphate metabolism in normal humans. Chronic extrarenal metabolic acidosis was induced by administering two different doses of NH4Cl [2.1 (low dose) and 4.2 (high dose) mmol/kg body wt per d, respectively] to four male volunteers each during metabolic balance conditions. Plasma [HCO3-] decreased by 4.5 +/- 0.4 mmol/liter in the low dose and by 9.1 +/- 0.3 mmol/liter (P < 0.001) in the high dose group. Metabolic acidosis induced renal hypophosphatemia, which strongly correlated with the severity of acidosis (Plasma [PO4] on plasma [HCO3-]; r = 0.721, P < 0.001). Both metabolic clearance and production rates of 1,25-(OH)2D increased in both groups. In the high dose group, the percentage increase in production rate was much greater than the percentage increase in metabolic clearance rate, resulting in a significantly increased serum 1,25-(OH)2D concentration. A strong inverse correlation was observed for serum 1,25-(OH)2D concentration on both plasma [PO4] (r = -0.711, P < 0.001) and plasma [HCO3-] (r = -0.725, P < 0.001). Plasma ionized calcium concentration did not change in either group whereas intact serum parathyroid hormone concentration decreased significantly in the high dose group. In conclusion, metabolic acidosis results in graded increases in serum 1,25-(OH)2D concentration by stimulating its production rate in humans. The increased production rate is explained by acidosis-induced hypophosphatemia/cellular phosphate depletion resulting at least in part from decreased renal tubular phosphate reabsorption. The decreased serum intact parathyroid hormone levels in more severe acidosis may be the consequence of hypophosphatemia and/or increased serum 1,25-(OH)2D concentrations.
 ...
PMID:Chronic metabolic acidosis increases the serum concentration of 1,25-dihydroxyvitamin D in humans by stimulating its production rate. Critical role of acidosis-induced renal hypophosphatemia. 146 97

Of 19 patients who had been receiving a therapeutic dosage of lithium carbonate for 10 to 20 years, 8 (42%) were found to have some laboratory evidence of hyperparathyroidism. Of the 3 who had parathyroid surgery, 2 had hyperplasia and 1 had a solitary adenoma, an unusually high incidence of hyperparathyroidism. Unusual features of lithium-induced hyperparathyroidism in this series include (1) low urinary calcium excretion and the absence of nephrolithiasis, (2) normal urinary cyclic adenosine monophosphate excretion, and (3) normal plasma inorganic phosphate. Eight patients (42%) required treatment for hypothyroidism. Three patients (16%) had impaired kidney function. While these observations do not contraindicate the continued use of lithium carbonate in manic depression, they strongly emphasize the need for close laboratory surveillance.
 ...
PMID:Hyperparathyroidism, hypothyroidism, and impaired renal function after 10 to 20 years of lithium treatment. 271 97

Citrate is used commonly as an alkalinizing agent and in the management of nephrolithiasis, but its quantitative effect on acid-base homeostasis, as judged by changes in renal net acid excretion, has not been delineated. We therefore administered 61 mEq of sodium citrate/day for 4 days to 10 normal volunteers and compared the results to those obtained in 10 normal subjects (4 of whom also participated in the citrate protocol) given 60 mEq/day for 4 days of sodium bicarbonate, the prototypical alkalinizing agent. We found that the sodium citrate group experienced an average reduction in net acid excretion (45.5 +/- 7.2 mEq/day) that was very similar to that (42.0 +/- 7.2 mEq/day) induced by the same amount of sodium bicarbonate. In both groups, the reduction in net acid excretion was equivalent to approximately 70% of the alkali administered. The latter appeared to relate to an average negative hydrogen ion balance of approximately 15 mEq/day, since there was an increase in blood [HCO3] in each group of about 2.5 mEq/l. We conclude that the findings demonstrate that the short-term effects of sodium citrate on acid-base homeostasis in normal subjects are indistinguishable from those of sodium bicarbonate.
 ...
PMID:Comparison of the effects of sodium bicarbonate versus sodium citrate on renal acid excretion. 283 30

To investigate whether overall tubular dysfunction is encountered in a particular subgroup of patients with urolithiasis, the following parameters of renal tubular function have been measured in fasting morning urine in 124 male stone formers: excretion of lysozyme and gamma-glutamyl transpeptidase (gamma-GT), fractional excretion (FE) or glucose, insulin, bicarbonate after an alkali load, and theoretical phosphate threshold (TmP/GFR). The following have been diagnosed: primary hyperparathyroidism (n = 3), medullary sponge kidneys (n = 5), hyperuricemia (n = 8), cystinuria (n = 1), struvite nephrolithiasis (n = 2), idiopathic hypercalciuria of the absorptive (n = 16), dietary (n = 46) or renal (n = 5) type, and normocalciuric idiopathic urolithiasis (n = 38). Urinary excretion of lysozyme and of gamma-GT were elevated in 14% and 21% of patients respectively; FE glucose and FE insulin were elevated in 6% and 8% of patients respectively. In 62% of the patients TmP/GFR was below 0.95 mmol/l and in 52% of the patients FE HCO3 after alkali load was above normal. The findings show that a large number of stone formers have signs of renal tubular dysfunction; apparent renal leaks of phosphate and of bicarbonate are the most frequently encountered defects; while they are not specific for a given etiologic group of patients, they have been found in each group. The latter observation suggests that nephrolithiasis itself can damage renal tubular function.
 ...
PMID:[Tubular dysfunction in renal lithiasis: cause or consequence?]. 285 24

To address whether a renal tubular dysfunction is encountered in a particular patient subgroup with urolithiasis, the following parameters of tubular function were measured in urine taken in the morning from 214 stone formers after fasting: pH, excretion of lysozyme and gamma-glutamyl transferase (gamma-GT); fractional excretion (FE) of glucose, insulin, Mg, K, and HCO3 after an alkali loading; and the renal threshold for phosphate (TmP/GFR). The following diagnoses were made in the patient group: primary hyperparathyroidism (N = 8), medullary sponge kidneys (N = 21), hyperuricemia (N = 10), cystinuria (N = 2), struvite stone disease (N = 6), idiopathic hypercalciuria of the absorptive (N = 25), dietary (N = 69) or renal (N = 7) type, and normocalciuric idiopathic urolithiasis (N = 66). In 31% of the patients TmP/GFR was below 0.80 mmole/liter and in 13% of the patients, FE HCO3 after alkali loading was above normal. Urinary excretion of lysozyme and that of gamma-GT both were elevated in 17% of the patients. FE glucose, FE insulin, FE Mg, and FE K were elevated in 8, 9, 3, and 7% of the patients, respectively. This study demonstrates that a significant number of stone formers present with signs of renal tubular dysfunction, primarily involving the proximal tubule since apparent leaks of phosphate and of bicarbonate were most frequently encountered. The defects were not specific for a given etiologic group of patients; on the other hand, occurrence was related to the presence of large stones in the pyelocaliceal system at the time data were gathered. Taken together these data suggest that the tubulopathy in nephrolithiasis is the consequence rather than the cause of the stone.
 ...
PMID:Tubulopathy in nephrolithiasis: consequence rather than cause. 287 Dec 16

Studies in 24 recurrent oxalate stone-formers have shown that values for urinary calcium excretion for this group on at-home diets vary significantly (P less than 0.001) more than values for creatinine excretions. By placing stone-formers on controlled in-hospital diets and measuring their calcium excretions, we were able to predict probable outpatient hypercalciuria (greater than 7.5 mmol/day) with a sensitivity of 95% and a specificity of 95%. In this study, the renal loss of calcium during low-calcium diets was proportional to the absorptive hypercalciuria during high-calcium diets. Calcium loading experiments in fasted stone-formers and normal subjects indicated that citrate, at citrate:calcium molar ratios ranging from 0.12 to 1, stimulated urinary calcium excretion more than did calcium carbonate loading alone. In addition, citrate also significantly (P less than 0.05) increased the excretion of urinary oxalate by two normal subjects for a given load of calcium oxalate. Malabsorption of citrate and possibly other hydroxycarboxylic acids may thus predispose to oxalate nephrolithiasis by promoting calcium and oxalate absorption.
 ...
PMID:Effect of citrate on the urinary excretion of calcium and oxalate: relevance to calcium oxalate nephrolithiasis. 291 May 76

A retrospective review of 199 black patients with urinary calculi and review of the census figures of the index hospitals revealed that white patients had urinary calculi 3 to 4 times as often as black subjects. The black male-to-female ratio was 1 to 1.55 compared to a ratio for white patients of 2.3 to 1. Calculi in black male subjects occur at a younger age than in black or white female or white male patients. The most common organisms cultured in black patients with stones were Escherichia coli and Proteus mirabilis. In contrast to the white population the most common type of stone formed in black patients was struvite/carbonate apatite. Stones of this type accounted for a third of all stones in male and 44 per cent in female subjects. We conclude that nephrolithiasis is an uncommon but not rare disease in the American black population.
 ...
PMID:Urinary lithiasis in the black population: an epidemiological study and review of the literature. 359 98

The association of a critical reduction in renal mass with the subsequent destruction of remaining nephrons has been observed in several species. We studied this process in experimental rabbits after 1 2/3 nephrectomy to define the course and its pathogenesis in this species. Control rabbits underwent sham operative procedures. After renal ablation, rabbits became increasingly cachectic and developed polyuria and hypertension. Despite food intake similar to that of controls (grams per kilogram per day), experimental rabbits developed severe hypercalcemia by 5 to 8 weeks after renal ablation, a change that persisted until death. During the study 17 experimental animals died of uremia 9 to 27 weeks after surgery, and the remaining seven experimental and 25 sham-operated rabbits were sacrificed at 5 to 7 months. At death, 19/24 experimental rabbits had severe obstruction of their collecting systems by concretions of gravel (n = 3) or large calcium carbonate stones (n = 16). Renal biopsy at 4 weeks revealed focal interstitial round cell infiltration progressing by 12 weeks to diffuse tubulointerstitial inflammation and fibrosis. Histologic evidence of obstruction was also evident at this time and became extensive on all subsequent examinations. By contrast, the glomeruli remained well preserved without evidence of sclerosis. We speculate that chronic hypercalcemia and, perhaps more significantly, urinary obstruction may have altered intrarenal hemodynamics and prevented the development of progressive sclerosis observed in the rat remnant kidney model. The present study describes an experimental model of chronic hypercalcemia and spontaneous calcium carbonate nephrolithiasis.
 ...
PMID:Subtotal nephrectomy in the rabbit: a model of chronic hypercalcemia, nephrolithiasis, and obstructive nephropathy. 371 20

The course of urogenital tuberculosis is complicated by unspecific bacterial infections of the urinary tract and nephrolithiasis. Among 605 patients with bacteriological or histological verified urogenital tuberculosis, 122 patients (20%) developed unspecific bacterial urinary infection--commonly caused by E. coli, proteus and pseudomonas--and 57 patients (9.4%) showed nephrolithiasis. In 42% of the lithiasis patients an urinary tract infection simultaneously occurred. 22 calculi are analyzed by the combined crystal-optical and x-ray-diffraction method with following results: 9 X struvite/carbonate apatite, 6 X calcium phosphate, 7 X calcium oxalate. The texture of 12 calculi was investigated on thin sections by polarization microscopy and a high concentration of organic material was found in both calcium oxalate and struvite/carbonate apatite calculi.
 ...
PMID:[Nonspecific pyelonephritis and the formation of urinary calculi in urogenital tuberculosis]. 373 37


1 2 3 4 Next >>