Total Urine Calcium Research Articles

A Prospective Study for the Prediction of Preeclampsia with Urinary Calcium Level

To assess the efficacy of calciuria as a diagnostic test for the prediction of preeclampsia, and also to determine the changes in urinary excretion of calcium in preeclampsia and normotensive women. A prospective study was conducted on 60 primi mothers in the age group of 20-30years, and all were enrolled at 16weeks of gestation with clinical follow up by 4weeks and 24h urinary calcium and creatinine estimation. Ten mothers developed preeclampsia (study groups) and fifty remained normotensive (control groups). By means of Receiver-operator curve, a cut-off level of urinary calcium in 24h was chosen for predicting preeclampsia. Preeclamptic women excreted significantly less total urine calcium (87.0±3.59mg/24h) than normotensive women (303.68±17.699mg/24h) (p<0.0001) at 40weeks of gestation. Urinary calcium and calcium/creatinine (Ca:Cr) ratio decreases progressively from 28weeks to 40weeks in the study group when compared to normotensive group. Preeclamptic women excrete less calcium than normotensive women. This parameter would predict preeclampsia earlier in pregnancy.

Disponibilidade biológica e exigências de cálcio em eqüinos em crescimento recebendo dietas com diferentes níveis de cálcio

Estudou-se o metabolismo de cálcio em eqüinos em crescimento recebendo dietas com diversos níveis desse mineral. Utilizaram-se 12 machos, com média de 12 meses de idade e peso vivo médio de 221,0 kg, mantidos com três dietas com 0,15; 0,45; ou 0,75 de cálcio e 0,23% de fósforo, constituindo um delineamento inteiramente casualizado, com três níveis de cálcio e quatro repetições. Foram injetados em cada animal, via jugular direita, os volumes de uma seringa, correspondentes a 7,4 MBq de 45Ca (CaCl2). Após a injeção, foram colhidas amostras (10 mL) de sangue, via jugular esquerda, aos 5 minutos, 1, 2, 4, 6, 24, 48, 72, 96, 120 e 144 horas. As fezes foram colhidas diariamente pela manhã, a partir de 24 horas após a aplicação do radionuclídeo até o sétimo dia e uma alíquota de 5% do total diário excretado foi colhida e armazenada em congelador para posterior análise. O mesmo procedimento das fezes foi adotado para a urina, quando foram colhidas amostras de 1% do volume total diário. Os níveis de cálcio plasmático, cálcio total na urina e cálcio endógeno nas fezes não diferiram entre os níveis de cálcio com valores médios de 11,76; 5,54 e 20,86 mg/kgPV/dia, respectivamente. A disponibilidade biológica de cálcio (média de 81,71%) também não diferiu entre os níveis de cálcio. As regressões lineares entre níveis de cálcio na dieta e cálcio total ingerido, cálcio absorvido, cálcio total nas fezes e cálcio retido foram expressas, respectivamente pelas equações: y=10,7+2,78x r²=1,0; y=12,41+2,24x r²=0,99; y=5,97+0,92x r²=0,93 e y=6,4+1,70x r²=0,94, com médias de, respectivamente, 135,80; 113,21; 47,37 e 82,90 mg/kgPV/dia.

The determination of total calcium in urine: a comparison between the atomic absorption and the ortho-cresolphtalein complexone methods

Atomic absorption spectrometry has been recommended as the reference method for the analysis of total calcium in body fluids and the ortho-cresolphtalein complexone (o-CPC) method has been widely used as the field method. We evaluated the performance of the Mega-Bayer, a fully automatic selective analyser, in determining total calcium in urine utilizing the o-CPC method. We assayed native urines with low, normal and high calcium concentrations. The two methods agreed well, according to least-squares analysis and the F-test, with Mega-Bayer having the upper limit of linearity two times higher (10 mmol/L) than that of the atomic absorption. The present method achieved excellent analytical goals and sistematic errors bellow half of the allowed limit goals recommended by the Clinical Laboratory Improvements Amendments. Final Rule. Laboratory Requirements (CLIA). We concluded that o-CPC in the Mega-Bayer equipment can confidently perform the total calcium urinary analysis with the advantage of being a fully automatized biochemical procedure and of allowing a wider linear analytical range.

A Neutral Carrier Membrane Calcium-Sensitive Electrode with Wide Working pH Range

Abstract A poly(vinyl chloride) (PVC) membrane calcium-sensitive electrode based on a new type of synthetic carrier 1,7-di[2-(1-phenylazo)naphtyl]-1,4,7-trioxaheptan is introduced. This electrode exhibited Nernstian response over the concentration range 1.0×10−1 - 3.0×10−8 mol/L Ca2+ with a slope of 28.8 mV/pCa in calcium ion buffer solutions. The detection limit for calcium ion was 1.0X10−8 mol/L. The response time varied from 10 to 30 seconds. The working pH range for the electrode was 3.5 - 12.3 when the concentration of Ca2+ was 10−3 mol/L. The lifetime of the electrode was proved to exceed 8 months. It was applied successfully in the determination of calcium ion in river water, mineral water and cosmetic. A method for the determination of total calcium in urine was developed.

New methods to determine the state of saturation of urine and to discriminate between the urine of control subjects and stoneformers

In this work a new method of determining the saturation of urine is reported. This is the first method which measures state of saturation in regard to all high affinity Ca 2+ -binding ligands in urine. The change in free calcium has been measured after addition of small aliquots of urine to a standard 1 m M CaCl 2 solution. This change has been extrapolated to a value characteristic of a concentrated urine solution. This extrapolated value has been termed the relative amount of free Ca 2+ in urine. Comparison of the relative free Ca 2+ in urine with the original free calcium in pure urine is a measure of the state of saturation of urine in regard to all high affinity Ca 2+ -binding ligands. Values for forty control subjects and sixty-eight stoneformers have been compared. Eighty-five percent of the control samples and fifty percent of the stoneformers' samples were unsaturated in terms of high affinity Ca 2+ -binding ligands. The method of determining relative free Ca 2+ in urine is a modification of the analate addition method used in analytical chemistry to determine total calcium in an unknown. The relative free Ca 2+ depends on the concentrations of both calcium and Ca 2+ -binding ligands present in urine. In forty healthy subjects, values ranged from −4.2 to 5.0 m M . In the sixty-eight stoneformers, the range was between −0.8 and 4.7 m M . A high degree of unsaturation in urine is indicated by the negative values. The relative free Ca 2+ is higher in stoneformers (mean 0.99 ± 1.19 SEM) than in the controls (mean 0.20 ± 1.85 SEM). Comparison of the relative free Ca 2+ and the total calcium in urine with various models of urine addition allows calculation of risk ratios of the sample being from a stoneformer. With ten additional samples of control and of stoneformers' urine, the predictions by one of these risk ratios showed a higher correlation with the source of the urine than either the concentration product ratio for oxalate or for phosphate.

Determination of calcium in urine by manual microtitration with EDTA

A simple, direct method for the determination of total calcium in urine by manual microtitration with EDTA at pH 12, with Calocin as fluorescent indicator, is proposed. By use of urine sample volumes of only 0.01–0.05 ml, interference from phosphate and natural fluorescence is minimized. For strongly naturally fluorescing urines the addition of potassium dichromate provides effective quenching. Agreement between results obtained by the proposed method and by atomic-absorption spectroscopy for a series of urine samples was satisfactory.