Concentration correlation with calcium

Anomalously high Ca concentrations in hair samples (up to 8285 (xgg-1) which correlate with high P concentrations (up to 4720 jxg g-1) from a group of women from Rio de Janeiro were detected by ICP-MS measurements.87 These abnormal hair compositions were related to endocrinological pathologies affecting calcium/bone metabolism. Very low Ca concentrations were observed in older women and were related to senile osteoporosis.87... 

The changes in calvarial phosphatase activities observed in animals treated with 25-(OH)D3 are totally different from those obtained with either 1.25-(OH)2D3 or 24.25—(OH)2D3. This fact indicates that physiological doses of 25-(OH)D3 may have an effect on cellular activity, independent of the conversion of this metabolite into these dihydroxyderivatives. The various effects of these vitamin D3 metabolites cannot be correlated with changes in serum calcium and/or phosphate concentrations. Among those factors other than serum calcium and phosphate concentrations that may be involved in the mechanism of action of vitamin D3 metabolites on bone phosphatase activities, the parathyroid hormone is of importance. This hormone is known to be a potent activator of bone phosphatases223,224,228. Parathormone increases the content of alkaline, neutral and acid phosphatases in mouse calvaria in vitro. Calcitonin does not prevent the increase of those enzymes while dichloromethylene diphosphonate causes a decrease in acid phosphatase and pyrophosphatase226. ... 

Cyclic uptake and release of Ca2+ from the extracellular medium occur during mitosis in Physarum pofycephalum, and correlate with specific structural and kinetic events in the mitotic nuclei.442 The membrane system in the mitotic apparatus in Haemantkus endosperm cells functions in the localized release of Ca2+, so regulating the events of mitosis.443 It is known that calcium exerts effects on the stability of spindle microtubules. An alternative view is that free magnesium concentration acts as the fundamental regulator of the cell cycle.444 Tubulin polymerization depends on the presence of magnesium and the absence of calcium, and control of the Ca2+/Mg2+ ratio is relevant to spindle assembly. 

The behavior of solutions of each substance was explored in the helix, lithium carbonate solution being the last used. The effect of concentration level was then examined with the solution in the equipment, lithium carbonate. It was discarded and replaced with calcium sulfate, which is being studied more intensely. It is hoped that the results of these runs will be correlated with those from pilot plants and operational plants distilling sea water. 

In cell culture preparations, diphenylhydantoin, carbamazepine and valproate have been shown to reduce membrane excitability at therapeutically relevant concentrations. This membrane-stabilizing effect is probably due to a block in the sodium channels. High concentrations of diazepam also have similar effects, and the membrane-stabilizing action correlates with the action of these anticonvulsants in inhibiting maximal electroshock seizures. Intracellular studies have shown that, in synaptosomes, most anticonvulsants inhibit calcium-dependent calmodulin protein kinase, an effect which would contribute to a reduction in neurotransmitter release. This action of anticonvulsants would appear to correlate with the potency of the drugs in inhibiting electroshock seizures. The result of all these disparate actions of anticonvulsants would be to diminish synaptic efficacy and thereby reduce seizure spread from an epileptic focus. 

The plasma concentration of calcidiol is the most sensitive and usefiil index of vitamin D status, and is correlated with elevated plasma parathyroid hormone and alkaline phosphatase activity (Table 3.4). As shown in Table 3.2, the reference range of plasma calcidiol is between 20 to 150 nmol per L, with a twofold seasonal variation in temperate regions. Concentrations below 20 nmol per L are considered to indicate impending deficiency, and osteomalacia is seen in adults when plasma calcidiol falls below 10 nmol per L. In children, clinical signs of rickets are seen when plasma calcidiol faUs below 20 nmol per L. The plasma concentration of calcitriol does not give a useful indication of vitamin D status. The reference range is between 38 to 144 pmol per L and is maintained because of the stimulation of calcidiol 1-hydroxylation by parathyroid hormone secreted in response to faUing concentrations of calcium (Holick, 1990). 

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