Fluorometric Determination of Calcium in Blood Serum.

Kepner, B. L.; Hercules, D. M.

doi:10.1021/ac60202a007

Cited by 118 publications

(22 citation statements)

References 22 publications

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“…The present study describes a chemical method for simple and rapid measurement of 100-1000pmol amounts of calcium in 5-20 ~tg dry tissue (or an equivalent amount of wet tissue) using a relatively cheap fluorometer. The method is based on the formation of a fluorescent calciumcalcein complex under alkaline conditions [15]. It allows the determination of the total calcium content and the 45calcium content of the same tissue samples.…”

Section: Discussionmentioning

confidence: 99%

The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

1982

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Summary. Glucose-stimulated 45calcium uptake and total calcium content of rat pancreatic islets has been studied, using a new fluorometric micro-method to estimate total calcium. Extracellular calcium was separated from incubated tissue by a rapid micro-filtration procedure. Islets incubated up to 60 min with calcium chloride 2.5mmol/1 and glucose 2.5mmol/1 maintained the same calcium content (670 + 7.5 pmol/gg DNA). When the glucose concentration was raised to 15mmol/1 no change in the total calcium content could be detected. On incubation with glucose 2.5 mmol/1 in the absence of calcium, the calcium content decreased to 488 + 27 pmol/gg DNA. On incubation with 4Scalcium chloride 2.5 mmol/1 for 5 or 30min at 2.5 mmol/1 glucose, islets exchanged 21 + 2 and 28 _ 1% of their total calcium content and, at 15 mmol/1 glucose, 30 + 3 and 45 ___ 2%, respectively. Thus, islet calcium has a high turn-over rate. Glucose stimulation results in an increase of the calcium uptake without enhancing the total calcium content and hence must increase the calcium-exchangeable pool.

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Section: Discussionmentioning

confidence: 99%

The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

1982

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“…In this assay, the average interassay variability of identical samples was 12.6%, and the lower limit of detection was 100 ng. Plasma calcium was measured by a fluorometric technique (14), and plasma phosphorus was measured by the method of Fiske and SubbaRow (15).…”

Section: Methodsmentioning

confidence: 99%

Effect of age on the conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 by kidney of rat.

Armbrecht¹,

Zenser²,

Davis³

1980

J. Clin. Invest.

109

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A B S T R A C T The decreased absorption ofcalcium by the small intestine of the adult may reflect changes in vitamin D metabolism with age. The purpose of this study was to compare the capacity of young (1.5 mo of age) and adult (12-mo In the adult rat, only 2.1±0.6% of the plasma radioactivity was in the form of 1,25-dihydroxyvitamin D3 after 24 h compared with 20.8±3.0% in the young. The conversion oftritiated 25-hydroxyvitamin D3 to its products was also measured directly in isolated slices of renal cortex. 1,25-Dihydroxyvitamin D3 production by adult renal slices was found to be less than one-tenth that of slices from the young. These results indicate that there is a marked decrease in the capacity of the vitamin D-deficient adult rat to convert 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3. This is probably due to the decreased capa.city of the adult kidney to 1-hydroxylate 25-hydroxyvitamin D3. These studies also demonstrate the usefulness of renal slices in measuring changes in the ren l conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 in the mammal.

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“…Each density fraction was then evaporated to dryness in air and analyzed for the concentration of calcium (22) and hydroxyproline (23). Bone carbonate levels were also measured in 5-wk uremic animals and their pair-fed controls.…”

Section: Methodsmentioning

confidence: 99%

“…Received for publication 15 June 1972 and in revised form 22 August 1972. bone cells and collagen turnover are increased in virtually all patients with chronic renal insufficiency despite absence of bone disease by routine radiographic analysis (6). Preliminary observations from this laboratory have revealed an increase in the soluble, immature bone collagen pool and a decreased concentration of mature, insoluble bone collagen (7).…”

Section: Introductionmentioning

confidence: 99%

Effect of Experimental Chronic Renal Insufficiency on Bone Mineral and Collagen Maturation

Russell¹,

Avioli²

1972

J. Clin. Invest.

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A B S T R A C T The effect of chronic renal disease on bone matrix and mineral maturation was evaluated in rats with experimental renal insufficiency of 2-11 wk duration utilizing bromoform-toluene gradient fractionation of bone powder, pulse labeling experiments with "5Ca and proline-'H differential extraction, an(d X-ray diffraction techniques.Maturation defects in both collagen and minieral (45Ca) metabolism were documented as early as 2 wk after the induction of uremia, when total bone calcium, inorganic phosphate, and hydroxyproline content were unchanged.The maturational defect progressed with advancing uremia despite insignificant changes in plasma pH and calcium, and normal bone carbonate levels.Although circulating levels of 25-hydroxycholecalciferol were significantly lower than normal in the uremic animals, pretreatment with either this vitamin D metabolite or vitamin D3 itself failed to alter the observed changes in skeletal maturation. INTRODUCTIONChronic renal failure is attended by a metabolic acidosis, intestinal malabsorption of amino acids (1) and minerals, alterations in vitamin D3 metabolism as well as increased circulating levels of parathyroid hormone, and uremic toxins such as indoles and guanidines. These biological derangements either singularly or in concert result in a form of osteopenia which because of its varied histological manifestation is termed "renal osteodys-

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Fluorometric Determination of Calcium in Blood Serum.

Cited by 118 publications

References 22 publications

The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

The effect of glucose stimulation on 45calcium uptake of rat pancreatic islets and their total calcium content as measured by a fluorometric micro-method

Effect of age on the conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3 by kidney of rat.

Effect of Experimental Chronic Renal Insufficiency on Bone Mineral and Collagen Maturation

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