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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The components of calcium and magnesium balance and the factors responsible for the maintenance of the serum concentration of these cations are reviewed. Within this framework, the causes and treatment of disturbances of the serum concentration are discussed. Hypercalcemia is usually a reflection of increased bone resorption and/or gut absorption with the kidney playing a secondary role. Hypocalcemia is usually due to either a disturbance in the parathyroid hormone-adenylate cyclase system or a disturbance in vitamin D metabolism. As vitamin D is required for expression of the action of PTH at bone and as PTH is a prime regulator of vitamin D metabolism, the absence of either component results in important disturbances in calcium balance. In contrast to calcium homeostasis, the kidney plays a major role in the determination and regulation of serum magnesium. The major causes of hypermagnesemia therefore are associated with loss of renal function, and hypomagnesemia is frequently due to renal magnesium wasting.
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PMID:Disorders of calcium and magnesium homeostasis. 703 37

A series of in vivo experiments were designed to study the early effects of phosphate depletion on calcium metabolism in young adult (8-10 week old) rats with intact thyroid--parathyroid glands. Hypercalciuria occurred within 24 h of dietary phosphate deprivation. It was the consequence of mobilization of calcium stores from the exchangeable calcium pool of the diaphysis of bone. Increased net intestinal absorption of calcium also occurred early. This was at least in part due to decreased net intestinal secretion of calcium into the gut lumen. Thus the early onset of hypercalciuria and hypercalcemia associated with Pi deprivation in normal growing young rats is the combined result of increased net intestinal calcium absorption and increased calcium mobilization from bone.
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PMID:Calcium metabolism in young rats during early dietary phosphate deprivation. 718 55

Interaction of calcium regulating hormone, active form of vitamin D3, and aspirin (ASA) was studied in rats. One alpha-hydroxyvitamin D3 (1 alpha-OH-D3) produced a hypercalcemia in parathyroidectomized, thyroparathyroidectomized and thyroparathyroidectomized nephrectomized rats. The effect of 1 alpha-OH-D3 was inhibited by treatment with 200, 50 and 20 mg/kg p.o. of ASA. ASA did not stimulate the gut absorption of calcium in vitamin D deficient rats. These data suggest that ASA acts by inhibiting 1 alpha OH-D3 induced bone resorption. This is the first report demonstrating the inhibitory effect of ASA on bone resorption as induced by 1 alpha-OH-D3, although partial inhibition of bone resorption in vitro has been reported.
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PMID:Aspirin inhibition of hypercalcemic effect of 1 alpha-hydroxyvitamin D3 in rats. 720 73

Vitamin D preparations [1-alpha-hydroxycholecalcifol (1-alpha OHD3) or 1,25-dihydroxycholecalciferol (1,25(OH)2D3)] may be administered orally, subcutaneously, intraperitoneally or intravenously. They may be given daily, sometimes in divided doses, or intermittently in large bolus doses, usually three times per week. A further variable is the timing of administration, which may be at night when the gut calcium load is at a minimum. In at least some studies high dose intermittent bolus administration of vitamin D can reduce parathyroid hormone (PTH) secretion by a mechanism separated in time from an increase in ionized calcium (iCa2+). In addition, some but not all studies have shown an improvement in calcium set point and in parathyroid gland sensitivity to calcium. It is also clear from a number of studies that this treatment can succeed where conventional daily administration has failed. Bolus intravenous therapy is most conveniently given after haemodialysis treatment sessions. Bolus oral therapy, perhaps administered prior to sleep, may achieve a similar objective (PTH suppression without hypercalcaemia) in patients on continuous ambulatory peritoneal dialysis (CAPD). It is also becoming apparent that the parathyroid gland may yet again escape following bolus therapy. The success of bolus therapy may lie in several not mutually exclusive mechanisms: high peak concentrations of 1,25(OH)2D3 directly affecting the parathyroid gland, improved compliance, and a small but significant increase in plasma iCa2+. Further long-term controlled trials are needed before bolus therapy can be generally recommended.
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PMID:Optimum route of administration of vitamin D in renal failure. 747 47

We have used antiserum to human parathyroid hormone-related protein (PTHrP) (1-16) to examine tissues and plasma of the dogfish (Scyliorhinus canicula) for the presence of immunoreactive PTHrP (irPTHrP). The plasma contained high concentrations of irPTHrP (9.34 +/- 0.37 pM), comparable to levels in humans with hypercalcaemia of malignancy. Other tissues with irPTHrP included brain neurones; epithelial cells of the saccus vasculosus, kidney, rectal gland and choroid plexus; and cells of the pituitary pars distalis. PTHrP was not detected in gut, skin, oviduct, and gill epithelia, nor in branchial cartilage. The principal source(s) of plasma PTHrP is not known.
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PMID:Immunodetection of parathyroid hormone-related protein in plasma and tissues of an elasmobranch (Scyliorhinus canicula). 763 75

First, it is important to find out whether the patient is complaining of infrequent defaecation, excessive straining at defaecation, abdominal pain or bloating, a general sense of malaise attributed to constipation, soiling, or a combination of more than one symptom. Second, one must decide if there is a definable abnormality as a cause of the symptom(s). Is the colon apparently normal or is its lumen widened (megacolon)? Is the upper gut normal or is there evidence of neuropathy or myopathy? Is the ano-rectum normal or is there evidence of a weak pelvic floor, mucosal prolapse, major rectocele, an internal intussusception or solitary rectal ulcer? Is there any systemic component such as hypothyroidism, hypercalcaemia, neurological or psychiatric disorder or relevant drug therapy? Choice of treatment will depend on this clinical evaluation. The range of treatments available is: Reassurance and stop current treatment: Patients with a bowel obsession may take laxatives or rectal preparations regularly without need. Increase dietary fibre: Most cases of 'simple' constipation respond to increased dietary fibre, possibly with an added supplement of natural bran. Toilet training and altered routine of life: Young people particularly may need to recognise the call to stool and alter their daily routine to permit and encourage regular defaecation. Medicinal bulking agent: Ispaghula, methyl cellulose, concentrated wheat germ or bran, and similar preparations are useful when patients with a normal colon find it difficult to take adequate dietary fibre. These preparations increase the bulk of stool and soften its consistency. They may be useful for those patients with the constipated form of irritable bowel syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Clinical management of constipation. 823 32

Vitamin D has been discovered at the beginning of this century. 7-Dehydrocholesterol is converted to vitamin D3 in the skin and after several hydroxylations it is further converted to the active hormonal form, 1 alpha,25-(OH)2D3. Vitamin D stimulates the absorption of calcium and phosphate and is an essential link in bone resorption and formation and calcium metabolism. 1 alpha,25-(OH)2D3 acts through a vitamin D receptor. These receptors are not only present in clinical target organs (kidney, gut, liver) but can also be found in a wide variety of "non-classical" tissues (keratinocytes, cells belonging to the immune system). Moreover, numerous cells (keratinocytes, macrophages) can locally synthetize or can be induced to synthetize 1 alpha,25-(OH)2D3 and these cells are responsive to its action. When these data are combined, a possible paracrine function of 1 alpha,25-(OH)2D3 can be suspected. Via this paracrine function 1 alpha,25-(OH)2D3 can suppress the cellular and humoral immunity. Based on the discovery of these effects on immune cells in vitro it became clear that 1 alpha,25-(OH)2D3 might be an interesting molecule to prevent autoimmune diseases and organ transplantation. This has already been shown in several animal models (Heymann nephritis, diabetes mellitus, experimental allergic-encephalomyelitis, lupus). 1 alpha,25-(OH)2D3 demonstrates however some side-effects (hypercalciuria, hypercalcemia, bone resorption) and for this reason 1 alpha,25-(OH)2D3-analogs are developed with dissociated effects i.e. an activity profile that allows a specific action on non-classical tissues without calcemic effects. Some chemical modifications of the side chain, A and/or CD-ring results in "superanalogs" with 10 to 100-fold more activity on cell differentiation and the immune system then 1 alpha,25-(OH)2D3 but with less calcemic activity in vivo. These biological effects can be explained by differences in pharmacokinetics (low affinity for the plasma vitamin D-binding protein and short extracellular half-life) and increased intracellular activation and gen transactivation. Preclinical research must still be done to select the most potent superanalogs and to find the exact protocols for the prevention and treatment of autoimmune diseases and rejection of transplanted organs.
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PMID:[Immune modulation by vitamin D analogs in the prevention of autoimmune diseases]. 857 69

Feeding problems, anorexia and vomiting are common in infants and children with chronic renal failure (CRF), and play a major role in the growth failure often found in this condition. However, the gastroenterological and nutritional aspects of CRF in children have received little attention, hence therapeutic interventions are usually empirical and often ineffective. Gastritis, duodenitis and peptic ulcer are often found in adults with CRF on regular haemodialysis and following renal transplantation. Despite persistent hypergastrinaemia, gastric acid secretion is decreased rather than increased in most of these patients, and active peptic disease appears to be promoted by the removal of the acid output inhibition (neutralisation of gastric acid by ammonia) that follows active treatment. Helicobacter pylori, on the other hand, does not seem to play a significant role in the pathogenesis of peptic disease in CRF. Gastro-oesophageal reflux has been found in about 70% of infants and children with CRF suffering from vomiting and feeding problems, and thus appears to be a major problem in these patients. In a number of symptomatic patients with CRF, gastric dysrhythmias and delayed gastric emptying have also been found; hence there appears to be a complex disorder of gastrointestinal motility in CRF. Serum levels of several polypeptide hormones involved in the modulation of gastrointestinal motility [e.g. gastrin, cholecystokinin (CCK), neurotensin] and the regulation of hunger and satiety (e.g. glucagon, CCK) are significantly raised as a consequence of renal insufficiency, and can be reverted to normal by renal transplantation. Furthermore, several other humoral abnormalities (e.g. hypercalcaemia, hypokalaemia, acidosis, etc.) are not uncommon in CRF. By directly affecting the smooth muscle of the gut or stimulating particular areas within the central nervous system, all these humoral alterations may well play a major role in the gastrointestinal dysmotility, anorexia, nausea and vomiting in patients with CRF. Specific pharmacological and nutritional interventions should thus be considered for the treatment of vomiting and feeding problems in CRF.
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PMID:Gastrointestinal function in chronic renal failure. 874 22

Alcoholic chronic pancreatitis and obstructive chronic pancreatitis are the most frequent and the better characterized types of pancreatitis. Recent advances in biology and genetics have brought new insights into the understanding of rare forms of chronic pancreatitis such as tropical chronic pancreatitis, hereditary chronic pancreatitis and chronic pancreatitis in cystic fibrosis. Some other rare forms of chronic pancreatitis have been identified: eosinophilic chronic pancreatitis, chronic pancreatitis after radiotherapy or during hypercalcemia, minimal change chronic pancreatitis and chronic pancreatitis associated with gut diseases or connectivitis. Recently, a particular form of non alcoholic chronic pancreatitis with duct destruction has been described often presenting as a pancreatic mass, leading in some cases to surgical resection of the pancreas. New insights into the understanding of chronic pancreatitis lead to new physiopathological concepts, and many arguments suggest that combined factors may lead to chronic inflammatory lesions of the pancreas.
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PMID:[Uncommon types of chronic pancreatitis]. 1248 56

The role of the calcium-sensing receptor (CaR), a G-protein-coupled receptor, is that of a calcium thermostat. The receptor regulates the synthesis and the secretion of the parathyroid hormone. The CaR is expressed not only in the parathyroid glands but also in the gut, the kidneys, and the bone cells. These three organs are the major components in the calcium homeostasis. The CaR regulates cell differentiation, proliferation, and membrane potentials in many other tissues both normal and malignant. Functionally important mutations in the CaR lead to changes in the calcium homeostasis and diseases. Mutations which improve the sensitivity lead to a familial form of hypocalcemia, while mutations which decrease the sensitivity cause hypercalcemia. Interestingly, reports on autoimmune antibodies causing a state of hypercalcemia have just been published. In secondary hyperparathyroidism the CaR has now become a target for treatment.
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PMID:[The human calcium-sensing receptor's role in illness and targets for therapy]. 1283 Jul 54


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