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)

Calcitriol is effective in suppressing PTH levels in haemodialysis patients with hyperparathyroidism but has a low therapeutic index. There is a search for other vitamin D sterols that suppress PTH but cause less hypercalcaemia. We review evidence that 1 alpha-hydroxy-vitamin D2 (1 alpha-D2) may be an effective and safer alternative to calcitriol. In vitamin D-deficient rats, 1 alpha-D2 is equipotent to 1 alpha-D3, which is converted to calcitriol before it acts; but, in normal rats, 1 alpha-D2 is much less toxic at high doses. In osteopenia models, either steroid-induced or following ovariectomy, 1 alpha-D2 is equal to or more effective than 1 alpha-D3 in preventing bone loss but causes less hypercalciuria. Studies in osteoporotic women reveal minimal hypercalciuria with 1 alpha-D2 at doses up to 4 micrograms/day, data suggesting greater safety than reported with calcitriol or 1 alpha-D3. Preliminary data in haemodialysis patients with secondary hyperparathyroidism demonstrate the efficacy of 1 alpha-D2 in suppressing PTH levels with minimal untoward effects on serum Ca and no effects on serum P. Taken together, these observations suggest that 1 alpha-D2 deserves strong consideration as a therapeutic agent for secondary hyperparathyroidism associated with end-stage renal disease.
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PMID:1 alpha-Hydroxy-vitamin D2: a new look at an 'old' compound. 884 Mar 32

To understand the mechanisms responsible for the persistent hypercalciuria and reduced glomerular filtration rate (GFR) previously found in 6 of 10 patients surgically cured of primary hyperparathyroidism (PHPx), the tubular handling of lithium, sodium, calcium, and phosphate as well as the renal hemodynamics were evaluated in these 10 PHPx patients, in 10 control subjects, and in 5 patients with renal hypercalciuria (RH), during fasting and after an oral calcium load. A positive correlation between the fractional excretions of calcium and sodium was found in all groups, but the PHPx patients excreted more calcium for the same amount of sodium than control subjects. The fractional proximal sodium reabsorption (FPRNa), distal delivery, and fractional phosphate reabsorption were similar in all groups; a significant positive correlation was found between the fractional calcium reabsorption and the FPRNa, indicating that proximal tubular function was preserved and that the urinary calcium losses in RH and in the hypercalciuric PHPx patients (h-PHPx) occurred in the distal nephron. However, only h-PHPx patients had reduced renal plasma flow, renal blood flow, and GFR, as well as a high renal vascular resistance, which was even more evident after the calcium challenge. These findings lead us to conclude that RH and h-PHPx patients are very different, as far as kidney dysfunction is concerned, and that a hypercalcemic nephropathy is the most probable cause of the alterations in distal calcium reabsorption and renal hemodynamics found in the h-PHPx patients.
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PMID:Changes in renal hemodynamics and tubular function of surgically cured primary hyperparathyroid patients are probably due to chronic hypercalcemic nephropathy. 979 75

Osteoporosis is increasingly recognised in men. Low bone mass, risk factors for falling and factors causing fractures in women are likely to cause fractures in men. Bone mass is largely genetically determined, but environmental factors also contribute. Greater muscle strength and physical activity are associated with higher bone mass, while radial bone loss is greater in cigarette smokers or those with a moderate alcohol intake. Sex hormones have important effects on bone physiology. In men, there is no abrupt cessation of testicular function or 'andropause' comparable with the menopause in women; however, both total and free testosterone levels decline with age. A common secondary cause of osteoporosis in men is hypogonadism. There is increasing evidence that estrogens are important in skeletal maintenance in men as well as women. Peripheral aromatisation of androgens to estrogens occurs and osteoblast-like cells can aromatise androgens into estrogens. Human models exist for the effects of estrogens on the male skeleton. In men aged > 65 years, there is a positive association between bone mineral density (BMD) and greater serum estradiol levels at all skeletal sites and a negative association between BMD and testosterone at some sites. It is crucial to exclude pathological causes of osteoporosis, because 30 to 60% of men with vertebral fractures have another illness contributing to bone disease. Glucocorticoid excess (predominantly exogenous) is common. Gastrointestinal disease predisposes patients to bone disease as a result of intestinal malabsorption of calcium and colecalciferol (vitamin D). Hypercalciuria and nephrolithiasis, anticonvulsant drug use, thyrotoxicosis, immobilisation, liver and renal disease, multiple myeloma and systemic mastocytosis have all been associated with osteoporosis in men. It is possible that low-dose estrogen therapy or specific estrogen receptor-modulating drugs might increase BMD in men as well as in women. In the future, parathyroid hormone peptides may be an effective treatment for osteoporosis, particularly in patients in whom other treatments, such as bisphosphonates, have failed. Men with idiopathic osteoporosis have low circulating insulin-like growth factor-1 (IGF-1; somatomedin-1) concentrations, and IGF-1 administration to these men increases bone formation markers more than resorption markers. Studies of changes in BMD with IGF-1 treatment in osteoporotic men and women are underway. Osteoporosis in men will become an increasing worldwide public health problem over the next 20 years, so it is vital that safe and effective therapies for this disabling condition become available. Effective public health measures also need to be established and targeted to men at risk of developing the disease.
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PMID:Osteoporosis in men. New insights into aetiology, pathogenesis, prevention and management. 988 98

During the past year, a newly reported clinical trial has strengthened the argument for recommending daily treatment with n-3 polyunsaturated fatty acids in patients with immunoglobulin A nephropathy (the most common form of primary glomerulonephritis in the world) who are at high risk for progression of renal disease. Studies are underway that involve a combination of cyclosporine A, a commonly prescribed immunosuppressive agent in solid-organ transplantation, with a high-potency n-3 polyunsaturated fatty acid to reduce cyclosporine toxicity. Two studies reported during the past year show promise that dietary supplementation with n-3 polyunsaturated fatty acids will substantially decrease vascular access graft thrombosis in patients receiving maintenance hemodialysis, and may reduce hypercalciuria in patients who suffer from kidney stones.
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PMID:n-3 Fatty acids and their role in nephrologic practice. 1149 58

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive tubular disorder that is frequently associated with progressive renal failure. The primary defect is related to impaired tubular reabsorption of magnesium and calcium in the thick ascending limb of Henle's loop. Mutations in PCLN-1, which encodes the renal tight junction protein paracellin-1 (claudin-16), were identified as the underlying genetic defects. Comprehensive clinical data and the results of PCLN-1 mutation analysis of 25 FHHNC families with 33 affected individuals are presented. Patients presented mainly with urinary tract infections, polyuria, and hematuria at a median age of 3.5 yr. At the time of diagnosis, the GFR was already decreased to <60 ml/min per 1.73 m(2) for 11 patients. Twelve patients exhibited progression to end-stage renal disease, at a median age of 14.5 yr. Treatment with magnesium salts and thiazides seemed to have no effect on the progression of the disease. Genotype analysis revealed PCLN-1 mutations in all except three mutant alleles (94%). Fifteen different mutations were observed, including eight novel mutations. The accumulation of mutations affecting the first extracellular loop was striking, with 48% of all mutant alleles exhibiting a Leu151Phe exchange. Haplotype analysis strongly suggested a founder effect among patients with FHHNC who originated from Germany or eastern European countries. In 13 of 23 families, hypercalciuria and/or nephrolithiasis were observed in otherwise unaffected family members, indicating a possible role of heterozygous PCLN-1 mutations in yielding hypercalciuric stone-forming conditions.
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PMID:Novel paracellin-1 mutations in 25 families with familial hypomagnesemia with hypercalciuria and nephrocalcinosis. 1151 80

The renal transplant (Tx) recipient is at risk for developing various complications including urolithiasis, the only manifestation of which may be hematuria. However, there are no data on the prevalence of microscopic hematuria in renal Tx recipients. The objective of our study was to determine the prevalence of microhematuria in our pediatric Tx patients and to investigate the causes of microhematuria. Records of all pediatric renal Tx recipients followed at our center from September 1999 to September 2000 were retrospectively reviewed; of the 21 patients, seven (33%) had persistent microscopic hematuria that was first noted 2.9 years post-Tx. Patients with and without hematuria had similar baseline characteristics. Only one patient had pre-existing hematuria that continued post-Tx. The etiology of hematuria in the other six patients was: recurrent IgA nephropathy (one patient), CMV nephritis (one patient), and unexplained (four patients). None had renal calculi or hypercalciuria. Three of the four patients with unexplained hematuria have chronic allograft nephropathy, and the fourth (original disease dysplasia) has hypocomplementemia. At their last follow-up, 5.3 years after onset of hematuria, all patients are alive with stable allograft function. In conclusion, microscopic hematuria is not uncommon in pediatric renal Tx recipients. While causes of post-Tx hematuria are diverse, stones are not commonly seen. Whether chronic allograft nephropathy per se can be implicated as a cause of hematuria remains to be determined. Renal biopsies should be considered at the onset of hematuria if proteinuria and/or deterioration in renal function are seen concomitantly, to look for recurrent or de novo glomerulonephritis.
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PMID:Microhematuria after renal transplantation in children. 1247 54

We report a 41-year-old man with hypomagnesemia, hypercalciuria, nephrocalcinosis, myopia and horizontal nystagmus. The hypomagnesemia was due to primary renal magnesium loss. He was diagnosed as having the syndrome of renal hypomagnesemia, hypercalciuria and nephrocalcinosis. This is a rare condition generally diagnosed by the first to third decades of life. Renal failure is common and end-stage renal disease can occur in children or young adults. The patient was treated with oral magnesium, chlorthalidone, potassium citrate and allopurinol and was followed up for 3 years. Treatment resulted in an improvement in hypercalciuria but serum magnesium level could not be normalized. The patient's renal function remains stable, with a mild degree of renal insufficiency.
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PMID:Renal hypomagnesemia, hypercalciuria and nephrocalcinosis in a middle-aged man. 1274 55

Acute lymphoblastic leukemia (ALL) in children can rarely present with severe lactic acidosis in the absence of a high white blood cell count or other complications. Renal tubular dysfunction with hypercalciuria and hypocalcemia in the absence of pre-existing renal disease or concurrent medications has not been described at presentation in childhood ALL. The authors describe a 7-year-old boy with ALL presenting with severe lactic acidosis and renal tubular dysfunction, both of which were refractory to conventional management and resolved rapidly with appropriate chemotherapy.
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PMID:Acute lymphoblastic leukemia presenting with lactic acidosis and renal tubular dysfunction. 1279 29

Over 70 years ago, potassium was found to have a natriuretic effect and was used in patients with heart failure. However, it took many years for its role in the control of blood pressure to be recognized. Recently, epidemiological and clinical studies in man and experimental studies in animals have shown that increasing potassium intake towers blood pressure and that communities with a high potassium intake tend to have lower population blood pressures. Several studies have shown an interaction between salt intake and potassium intake. However, the recent DASH-Sodium (Dietary Approaches to Stop Hypertension) study demonstrates an additive effect of a low salt and high potassium diet on blood pressure. Increasing potassium intake may have other beneficial effects, for example, reducing the risk of stroke and preventing the development of renal disease independent of its effect on blood pressure. A high potassium intake reduces calcium excretion and could play an important role in the management of hypercalciuria and kidney stone formation, as well as bone demineralization. Potassium intake may also play an important role in carbohydrate intolerance. A reduced serum potassium increases the risk of lethal ventricular arrhythmias in those at risk, i.e. patients with ischemic heart disease, heart failure or left ventricular hypertrophy, and increasing potassium intake may prevent this. In this article, we address the evidence for the important role of potassium intake in regulating blood pressure and other beneficial effects of potassium which may be independent of and additional to its effect on blood pressure.
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PMID:Potassium: more beneficial effects. 1501 47

Low-molecular-weight (LMW) proteinuria has been described in patients with primary distal renal tubular acidosis (dRTA). However, other proximal renal tubular dysfunctions have rarely been reported. In this report we describe reversible and multiple proximal renal tubular cell dysfunctions in a patient with dRTA. A 4-year-old girl was admitted to our hospital for investigation of short stature and proteinuria. Laboratory studies revealed a hyperchloremic metabolic acidosis without aciduria, hypokalemia, hypouricemia with uricosuria, hypercalciuria, LMW proteinuria, phosphaturia, and generalized aminoaciduria. The patient was diagnosed as having dRTA with multiple proximal renal tubular dysfunctions. All proximal renal tubular dysfunction subsided 1.5 years after starting alkali therapy. The precise pathogenic mechanisms underlying the development of multiple proximal renal tubular dysfunctions in dRTA remained unclear. However, proximal renal tubular endosomal dysfunction resulting from a profound intracellular acidosis caused by vacuolar H+-ATPase dysfunction or hypokalemic nephropathy might contribute to the development of proximal renal tubular dysfunctions in patients with dRTA.
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PMID:Proximal renal tubular dysfunction in primary distal renal tubular acidosis. 1554 7


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