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

The effects of calcium-gluconate infusions on renal function were studied in unanesthetised dogs. Each dog was studied during hydropenia and saline infusion. Hypercalcemia, mean serum calcium 3.85 mmol/l (hydropenia) and 3.62 mmol/l (saline infusion), increased fractional excretion of sodium (CNa/CIn), calcium (CCa/CIn), and magnesium (CMg/CIn). The increase was significantly higher in saline-expanded dogs than in hydropenic dogs. Fractional excretion of potassium (CK/CIn) was increased in hydropenia but remained unchanged in saline-expanded animals. Fractional excretion of phosphate (Cp/CIn) was not consistently changed by hypercalcemia. Fractional excretion of chloride (CCl/CIn) was markedly increased in saline-expanded dogs but was not changed in hydropenia. Urine osmolality was reduced in hydropenic dogs but unchanged in saline-expanded dogs. In hydropenic as well as in saline-expanded dogs tubular reabsorption of solute-free water (TcH2O/CIn) increased during the first hour of hypercalcemia. In hydropenic dogs hypercalcemia caused a slight but significant decrease in blood pH, standard bicarbonate, and base excess. In hydropenic as well as in saline-expanded dogs glomerular filtration rate (CIn), renal plasma flow (CPAH), and filtration fraction were unaffected.
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PMID:Renal function in hypercalcemic dogs during hydropenia and during saline infusion. 4 8

Rhesus monkey (Macaca mulatta) were subjected to hypercalcaemia by daily intramuscular injections of vitamin D2 (100,000 IU) and by providing them gram soaked in 1% CaCl2 solution for eating and 1% CaCl2 solution (prepared in tap water) for drinking. After 10, 15, 20 and 30 days of such treatment the serum calcium level recorded a rise (18.24 +/- 0.56, 26.20 +/- 1.30, 17.25 +/- 0.25 and 20.50 +/- 0.55 mg/dl respectively) as compared to those of control animals (12.80 +/- 1.00, 12.30 +/- 0.50, 12.70 +/- 0.20 and 12.30 +/- 0.30 mg/dl). Serial sections of thyroid parathyroid complex and isthmus were subjected to selective staining for lcalising the C cells. The structure and behaviour of these cells both under normal and experimental conditions has been studied. Hypercalcaemia resulted in the increase of these cells. Mitotic figures of the C cells were also encountered after 10 days of hypercalcaemia. The specimens subjected to 30 days treatment showed complete degranulation of these cells. Chronic hypercalcaemia inhibits the activity of parathyroid cells which display degenerative changes. The anterior and posterior poles, the peripheral regions of thyroid and isthmus are completely devoid of calcitonin cells.
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PMID:Thyroid calcitonin cells and parathyroid gland of the Indian rhesus monkey Macaca mulatta in response to experimental hypercalcaemia. 11 36

Long term hypercalcaemia was induced in F. pennanti by alternate day intramuscular injections of 50,000 IU of vitamin D2 and by giving them 1% CaCl2 solution prepared in tap water to drink. The controls were not injected with vitamin D2 and were given tap water. The serum calcium levels at various stages of the experiment (1-29 days) show increased values as compared with those of control animals. The calcitonin cells in the treated animals generally exhibit an increase in their number up to the 15th day. Mitotic figures are also encountered between the 7th and the 15th day of treatment. This exhibits the increase in the number of C cells. Constant calcium challenge results in increased quantities of secretory granules among these cells up to the 15th day and in degranulation from the 17th day onwards. It also causes degenerative changes in a certain number of C cells. The parathyroids exhibit atrophic changes (25 days onwards) due to chronic hypercalcaemia. For short term hypercalcaemia, animals were injected intravenously with 1 ml of 10% solution of calcium gluconate. The calcitonin cells do not exhibit any change during the first half hour but thereafter they exhibit progressive degranulation, resulting in marked degranulation after 5 hours of the injection. The parathyroids remain unaffected throughout the experiment and show no histological change.
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PMID:Studies of calcitonin cells and parathyroid glands of the Indian palm squirrel, Funambulus pennanti in response to experimental hypercalcaemia. 31 55

To examine the relative importance of calcium and gastrin in regulation of calcitonin secretion, we administered graded oral doses of calcium to 10 normal men, ages 23-29 yr. Each subject had previously shown an appropriate increase in calcitonin secretion in response to a pharmacologic (0.5 mug/kg) pentagastrin injection. On separate days and in random order, each man drank 250 ml of distilled water containing 0.0, 0.5, 1.5, and 3.0 g of elemental calcium as the gluconate salt. Blood samples were drawn before and at 30, 60, 90, 120, 180, and 240 min after the oral calcium dose. The samples were analyzed for calcium by atomic absorption spectroscopy, and for gastrin and calcitonin by radioimmunoassays of established sensitivity and specificity. Ingestion of water (control) caused no change in any of the three variables. Calcium ingestion resulted in dose-related increases, within the normal range, of all three variables. Immunoreactive gastrin rose promptly, peaking at 30 min, and returning to basal levels or below by 120 min. In contrast, calcium and immunoreactive calcitonin levels rose slowly and in parallel, peaking at 120-240 min. Changes in calcitonin and changes in calcium were strongly and positively correlated, r = 0.73, when all data were pooled. Furthermore, individual linear regressions for changes in calcitonin and calcium levels (calculated separately for the three oral calcium doses in each subject) had positive slopes in 28 out of 30 sets (P < 0.01). The changes in calcitonin concentrations were much more poorly correlated with the corresponding changes in serum gastrin levels; in fact, the regression coefficient was weakly negative, r = -0.20. These results show that, at least in young adult men, changes of ambient calcium concentration within the normal range may be of major importance in physiologic regulation of calcitonin secretion. The findings are consistent with the hypothesis that calcitonin functions to prevent excessive postprandial hypercalcemia.
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PMID:Regulation of calcitonin secretion in normal man by changes of serum calcium within the physiologic range. 50 Aug 34

1. Hypercalcemia was induced in S. murinus by alternate day intramuscular injections of vitamin D (25 000 IU) and by providing them 1% CaCl2 solution (prepared in tap water) for drinking. 2. After such a treatment the serum calcium values recorded a rise as compared to those of the control specimens. 3. The histological picture of the thyroid of the treated specimens reveals increased number of calcitonin cells. This observation is supported by the occurrence of mitotic figures among them. 4. Perpetual calcium challenge results in degranulation of the secretory material (calcitonin) among these cells (at 26th and 30th day of treatment). 5. It also results in degenerative changes in certain number of C cells. 6. The blood capillaries around these cells get dilated and secretory granules of C cells tend to gather at the periphery of cytoplasm and towards vascular pole. 7. The parathyroid shows atrophic changes.
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PMID:Studies of calcitonin cells and parathyroid gland of house shrew, Suncus murinus in response to experimental hypercalcemia. 53 67

Hypercalcaemia would seem to be rare during immobilisation, whilst osteoporosis and hypercalciuria are constant. In fact, it often goes unnoticed. The case presented here confirms its predominance in the adolescent male. The reason for immobilisation seems to be irrelevant. The clinical symptoms are very variable: polydipsia, nausea, headache, apathy, anorexia. Blood calcium levels are raised, up to 14 mg%. This hypercalcaemia is due to very marked bone loss in adolescents, secondary to hyper-resorption and a temporary stoppage in osseous formation. The differential diagnosis from primary hyperparathyroidism is sometimes difficult but is aided by laboratory and histological findings. The essential is to consider the possibility of immobilisation hypercalcaemia in the presence of any suggestive symptoms in an immobilised adolescent. Treatment includes a return to weight bearing, adequate water intake and the administration of phosphorus, calcitonin, furosemide, and corticosteroids.
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PMID:[Immobilisation hypercalcaemia (author's transl)]. 59 68

In intact eels in sea water (SW), ovine prolactin (PRL) treatment induces hypercalcemia, but its mechanism of action, which is discussed, remains to be defined. Corpuscles of Stannius (CSt) are modified simultaneously: two cell categories then become evident. The first cell type (type 1) predominates; it has an oval shape and large granules, it shows a nuclear and nucleolar hypertrophy and a mitotic activity, and appears greatly stimulated by PRL; it may elaborate a hypocalcemic factor (hypocalcin) which would compensate for the PRL-induced hypercalcemia. A similar effect, although slightly less intense, is detected in hypophysectomized-PRL treated eels in SW. A second cell type (type 2), is more elongated, smaller in size, and has an oval nucleus and fine granules. Scarcely less active in SW, it is significantly stimulated by PRL despite an increased blood sodium and potassium level. This experiment does not help to clarify its function.
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PMID:Prolactin, hypercalcemia and corpuscles of Stannius in seawater eels. 62 14

Plasma concentrations of calcium fractions, proteins, phosphate and magnesium were measured before, during and after cardiopulmonary bypass in 15 patients undergoing cardiac surgery. When calcium chloride was added to a pump priming solution which contained little or no blood, the concentrations of all calcium fractions were significantly greater after bypass than before, with a mean ionized calcium concentration of 1.52 mmol litre-1 plasma water, 30 min after completion of bypass. This iatrogenic hypercalcaemia was increased significantly by the administration of more than 10 mg kg-1 calcium chloride in the first 30 min after bypass. Other plasma constituents showed the dilutional effect of the pump prime during bypass and only the magnesium concentration failed to return towards normal values after operation.
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PMID:Changes in ionized calcium and other plasma constituents associated with cardiopulmonary bypass. 70 63

Unilateral tibial fractures were produced in adult, 1-year-old, male Sprague-Dawley rats. The animals were then treated for 6 weeks with daily doses of 2.5 micrograms, 1.25 micrograms or 0.125 microgram 1alpha-hydroxycholecalciferol (1alpha-OH-D3). The aim of the investigation was to study the effect of this treatment on the healing process of the fracture and on the composition of the fractured bone. The general effect of 2.5 micrograms of 1alpha-OH-D3 was a significant loss of body weight (20 per cent) and hypercalcaemia. The lower dose levels, however, did not affect the body weight, and with a dose of 0.125 microgram the serum calcium level did not increase significantly. The healing rate of the fractures increased in all treatment groups as compared with the controls. The water content of the fractured tibias increased in the rats treated with 2.5 micrograms doses but decreased in the other groups. On the other hand the mineral content increased in the groups treated with 1.25 micrograms and 0.125 microgram doses and decreased in the largest dose group. Furthermore the amount of organic material per wet weight increased with the 2.5 micrograms dose and was mainly unchanged in the other groups. The hydrated bone density and the cortical thickness of the tibia increased most significantly in the group treated with 0.125 microgram but the trabecular bone area of the periosteal callus did not increase significantly. The conclusion is drawn that treatment with small doses of 1alpha-OH-D3 has a beneficial effect on the healing rate and on the mineralization of the fracture callus, and on cortical bone formation.
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PMID:The effect of 1alpha-hydroxycholecalciferol on the healing of experimental fractures in adult rats. 73 73

The effects of acute hypercalcemia on hemodynamics and on water and sodium excretion were studied on the blood-perfused isolated dog kidney. This model advantageously eliminates various factors which modify medullary osmolality and intrarenal hemodynamics, as well as collecting duct permeability. Calcium ion directly inhibits sodium reabsorption in the proximal tubule and in the ascending limb of Henle's loop, leading to increased sodium excretion rate and to decreased free water generation. The vasoconstrictive action of calcium, leading to decreased glomerular filtration rate, may mitigate the strong natriuretic effect of this ion.
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PMID:Effects of hypercalcemia on water and sodium excretion by the isolated dog kidney. 94 13


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