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

In Sarotherodon mossambicus prolactin cell activity is related to ambient Ca2+ levels, and prolactin has hypercalcemic activity in this species. To study whether prolactin has a direct action on calcium metabolism, or whether prolactin's relationship with calcium is indirect and connected with control of gill permeability, the effects of external Ca2+ and Mg2+ on prolactin secretion and gill permeability were compared. It appeared that high external Mg2+ was associated with reduced prolactin secretion, even though high Mg2+ resulted in a marked hypocalcemia. Exposure of fish to high Ca2+ levels led to hypercalcemia. Both high Mg2+ and high Ca2+ concentrations in the ambient water reduced the osmotic water permeability of the gills. These results represent further evidence that prolactin secretion in S. mossambicus may be affected by any external factor that interferes with branchial permeability. It is concluded that prolactin's main function in this species is connected with control of branchial permeability rather than calcium metabolism, although internal calcium may be implicated in permeability control.
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PMID:Effects of external Mg2+ and Ca2+ on branchial osmotic water permeability and prolactin secretion in the teleost fish Sarotherodon mossambicus. 665 34

The effect of hypomagnesemia on renal concentrating ability was assessed in rats fed diets either low in magnesium or low in magnesium and calcium for 30 days. The rats fed a low-magnesium diet became hypomagnesemic (0.26 +/- 0.03 versus 1.53 +/- 0.04 mEq/L in controls), hypercalcemic (5.96 +/- 0.04 versus 5.22 +/- 0.11 mEq/L in controls), and hypokalemic (3.1 +/- 0.1 versus 4.2 +/- 0.4 mEq/L in controls) with decreased muscle content of potassium. Despite being hypomagnesemic, hypercalcemic, and potassium depleted, the rats had normal renal concentration ability (2499 +/- 65 versus 2415 +/- 119 mOsm/kg H2O in control). Those rats fed a diet low in both magnesium and calcium became hypomagnesemic (0.41 +/- 0.08 versus 1.53 +/- 0.04 mEq/L in controls) but were hypocalcemic. They also had normal renal concentrating ability (2399 +/- 109 versus 2415 +/- 119 mOsm/kg H2O in controls). It is concluded that hypomagnesemia does not decrease renal concentrating ability in rats. Furthermore, a normal concentrating ability demonstrated in hypomagnesemic rats, in spite of hypercalcemia and potassium depletion suggests that hypomagnesemia may ameliorate the deleterious effects of hypercalcemia and/or potassium depletion on renal concentrating ability.
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PMID:The effect of hypomagnesemia with or without associated hypercalcemia on renal concentrating ability in rats. 665 59

Direct measurement of plasma AVP and indirect assessment of antidiuretic activity during standard dehydration tests were made in 21 polyuric and polydipsic patients to establish the efficacy of each method in determining the cause of polyuria. Patients with acquired nephrogenic diabetes insipidus (e.g. diabetes mellitus, renal failure, hypercalcaemia) were excluded from the study. Cranial diabetes insipidus was diagnosed by plasma AVP responses to osmotic stimulation during infusion of hypertonic 5% saline which were subnormal in 13 patients, 4 of whom had undetectable plasma AVP and 3 who had reduced but osmoregulated AVP release. Standard water deprivation tests confirmed cranial diabetes insipidus in all but 2 patients who were diagnosed as partial nephrogenic diabetes insipidus. The remaining 8 patients had normal, osmoregulated AVP secretion; the cause of their polyuria was determined by their renal response to desmopressin. Two patients had nephrogenic diabetes insipidus and 6 had primary polydipsia. The majority of polyuric patients could be accurately diagnosed by carefully performed dehydration tests. We suggest that direct measurements of plasma AVP during osmotic stimulation are only necessary to distinguish mild forms of cranial from nephrogenic diabetes, or to define precisely the characteristics of AVP secretion.
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PMID:A comparison of diagnostic methods to differentiate diabetes insipidus from primary polyuria: a review of 21 patients. 665 43

Individuals with cancer are subject to fluid and electrolyte imbalances because of the original disease process, therapy, and complications resulting from both the disease process and from therapy. These imbalances are life threatening either when they become extreme or when they occur very rapidly. Although almost any fluid and electrolyte disorder or combination of disorders can occur in people with cancer, this article will focus on the following more common, potentially critical imbalances: water excess, decreased vascular volume, hypercalcemia, hypokalemia, and tumor lysis syndrome, which includes hypocalcemia, hyperphosphatemia, hyperuricemia, and hyperkalemia. These imbalances will each be reviewed with a focus on their causes, signs and symptoms, and treatment. Additional readings on fluid and electrolyte imbalances in patients with cancer can be found in several recent articles.
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PMID:Fluid and electrolyte disturbances associated with cancer and its treatment. 675 72

In outlining the pathology of various electrolyte metabolism abnormalities in cancer patients we considered the main clinical points between pathologies and emergency treatment. In regard to sodium (Na+) metabolism, one pathologic state that requires our attention is hypernatremia. Hypernatremia is accompanied with dehydration and is due to water loss, vomiting, diarrhea and renal insufficiency. One of the major causes of this condition is lack of the antidiuretic hormone due to intracranial metastasis of the tumor. When hypernatremia becomes severe, it is accompanied with circulatory failure, muscular asthenia, disorientation, convulsions, coma and other cerebral symptoms. Treatment consists of replenishing the water content by infusion of electrolyte solutions which should be carefully conducted after complete diagnose of the severity of the patient's pathological condition. Hyponatremia, like sick cell syndrome, is observed relatively frequently in cancer patients. When the serum Na level falls markedly, it induces cerebral edema and causes disorders of consciousness. The major treatment consists of providing both water and sodium supplements. Hyperkalemia is observed at the time of renal insufficiency, tissue lesions, vomiting, and diarrhea. When serum potassium level rises, it causes bradycardia, ventricular fibrillation, or cardiac arrest. It is important to diagnostically apprehend the severity of this condition using EKG and determining the serum K1+ level. For emergency treatment injection of calcium gluconate is very effective. Hypokalemia is often manifested by the loss of intestinal fluids due to diarrhea or during administration of diuretic agents. Clinical symptoms include neural paralysis but emergencies occur relatively infrequently. K C1 injections are used in treating this condition. Hypercalcemia is manifested in cancer patients during hyperparathyroidism. Its clinical symptoms include lassitude, tachycardia, nausea, vomiting, and renal dys-function, leading to neural symptoms in severe cases. The main treatment consists of injection of physiological saline solution and administration of calcitonin, mithramycin. Hypocalemia is manifested during renal insufficiency, lack of vitamin D, and hypothyroidism. In classic cases it causes tetanic spasms. Injection of calcium is an effective treatment but since during tetanic spasms alcalosis may easily occur, treatment should only be provided after obtaining a complete understanding of the patient's condition. The pathological conditions described above can not be said to specific to cancer but it should be kept in mind that one of their main causative factors is the involvement of mechanism which produces ectopic hormones from cancerous tissues.
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PMID:[Electrolyte metabolism and emergency]. 688 72

The effect of interaction between calcium and prostaglandin (PG) on the action of antidiuretic hormone (ADH) was studied in the water-diuresing anesthetized dog. Maximal urinary osmolality after 100 mU or ADH was 331 +/- 24 in the normocalcemic state versus only 228 +/- 31 mosmol/kg (P less than 0.01) in dogs made acutely hypercalcemic when their serum Ca concentration was increased from 8.9 +/- 0.2 to 11.6 +/- 0.4 mg/100 ml (P less than 0.001). To define the role of PG in this effect, studies were performed in the presence of PG inhibition with indomethacin (10 mg/kg). The antidiuretic response to 100 mU of ADH was decreased by hypercalcemia, as maximal osmolality was 1,096 +/- 65 in the normocalcemic PG-inhibited dog but only 555 +/- 50 mosmol/kg in the acutely hypercalcemic PG-inhibited dog (P less than 0.001). Conversely, the effect of PG inhibition to enhance the hydroosmotic effect of ADH was also demonstrable in acutely hypercalcemic dogs, as maximal urinary osmolality following 100 mU of ADH was 257 +/- 9 before and 557 +/- 60 mosmol/kg after PG inhibition (P less than 0.001). These studies demonstrate, therefore, that the effect of acute hypercalcemia on the hydroosmotic response to vasopressin is not dependent on the synthesis of an endoperoxide metabolite. Likewise, hypercalcemia blunts but does not abolish the effect of PG inhibitors to potentiate the hydroosmotic effect of ADH.
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PMID:Calcium-prostaglandin interaction on the action of antidiuretic hormone in the dog. 706 41

Thirty-five patients with primary or radiation-induced hyperparathyroidism underwent autotransplantation with fresh diseased parathyroid tissue. Due to previous neck surgery (34 percent), concomitant thyroid surgery (66 percent), and a high proportion of multiglandular parathyroid disease (43 percent), all patients ran a high risk of becoming hypoparathyroid, At follow-up , a mean of 28 months after operation, 32 patients had normal parathyroid function, 2 had hyper- and 1 had hypoparathyroid function. The amount of tissue used for transplantation was individually chosen by relating the serum calcium level to the total parathyroid mass. In patients with water-clear cell hyperplasia and thus low endocrine activity on a weight basis, large grafts were needed, whereas less than 120 mg was used in most other cases. In two of our three failures we did not follow these tactics. Our results show that autografting fresh diseased parathyroid tissue can minimize the occurrence of postoperative hypoparathyroidism in patients at high risk of this complication. In no case has recurrent or progressive hypercalcemia developed.
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PMID:Autotransplantation of fresh diseased parathyroid tissue in primary and radiation-induced hyperparathyroidism. 708 72

The effect of plasma ionized calcium concentration on left ventricular function was studied in the canine heart on right heart bypass. Stroke volume, mean arterial pressure and heart rate were controlled. Plasma ionized calcium was lowered to 0.58 +/- 0.01 mM by citrate infusion and raised to 1.70 +/- 0.01 mM by calcium chloride infusion in random order in each dog. Left ventricular function at each of these ionized calcium levels was compared with that in an immediately preceding normocalcemic period. At a constant stroke work (16.9 +/- 0.2 g-m), sustained hypercalcemia was associated with a small decrease in left ventricular end-diastolic pressure (1.7 +/- 0.7 cm H2O, p less than 0.05) despite a marked increase in peak left ventricular dP/dt (first derivative of ventricular pressure) averaging 34 percent (p less than 0.001). Coronary blood flow, tension-time index and myocardial oxygen consumption were not significantly altered. Stroke work determined at a left ventricular end-diastolic pressure of 14 cm H2O, by interpolation in left ventricular function curves, was 11 +/- 4.4 percent above that at control normocalcemia (p less than 0.05). At a constant stroke work (16.9 +/- 0.2 g-m), sustained hypocalcemia was associated with a marked depression of left ventricular function as demonstrated by a substantial increase (from 4.9 +/- 0.3 to 12.7 +/- 1.1 cm H2O, p less than 0.0001) in left ventricular end-diastolic pressure (p less than 0.0001), decreased mean systolic ejection rate (p less than 0.01) and decreased peak left ventricular dP/dt (p less than 0.0001). Coronary blood flow increased (p less than 0.05) whereas myocardial oxygen consumption did not change significantly. A marked displacement of left ventricular function curves to the right (compared with curves obtained during normocalcemia) was observed, and stroke work determined at a left ventricular end-diastolic pressure of 14 cm H2O was 52 +/- 5.4 percent below control level (p less than 0.001). It appears that hypercalcemia, when initiated from a normal control level, provides only a small enhancement of ventricular pump performance (as indexed by the stroke work-left ventricular end-diastolic pressure relation) despite a marked increase in peak left ventricular dP/dt, whereas marked improvement of left ventricular performance may be expected when calcium infusion is initiated from an ionized calcium level that is below normal.
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PMID:Relation between ionized calcium concentration and ventricular pump performance in the dog under hemodynamically controlled conditions. 722 49

Persisting modifications induced by repeated intravenous calcium infusion (acute hypercalcaemia) were investigated in 6 Thomas fistula dogs: 4 controls and 4 calcium-treated dogs, two of which were studied as controls. (a) The pancreatic response to graded doses of synthetic secretin (water and bicarbonate outputs) was significantly reduced in calcium-treated dogs when compared with controls. As both the D50 for secretin-induced response increased, and the maximal secretory response decreased, if may be concluded that calcium treatment decreased the sensitivity of duct cells to secretin and reduced their secretory capacity. (b) A similar dose-response relationship was observed between secretin and pancreatic calcium outputs in controls and calcium-treated dogs. The secretin induced pancreatic calcium secretion was independent of protein secretion and latter not being modified by secretin. Thus it may be assumed that the secretory fluid calcium originated form a protein independent pool and had a dose-dependent relationship to secretin. (c) These results help to illuminate the aetiology of chronic pancreatitis induced by acute hypercalcaemia and by hyperparathyroidism.
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PMID:Response of the exocrine pancreas to graded doses of secretin in calcium-treated and normal dogs. 725 71

Effect of vitamin D3 administration (12,000 IU/100 g body wt.) on levels of serum calcium and inorganic phosphorus levels in the smooth water snake, Enhydris enhydris was investigated. Hypercalcemia and hyperphosphatemia was observed from day one till the end of the experiment (day 14). Maximum values were recorded on the 4th day followed by a steady decline.
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PMID:Effects of vitamin D3 administration on the levels of serum calcium and inorganic phosphorus in the smooth water snake, Enhydris enhydris (Schneider). 766 Aug 31


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