Albumin-adjusted calcium concentration in serum increases during normal pregnancy

1990 ◽  
Vol 36 (1) ◽  
pp. 142-144 ◽  
Author(s):  
R B Payne ◽  
A J Little ◽  
R T Evans
Keyword(s):  
Calcium Concentration ◽  
Normal Pregnancy ◽  
Ionized Calcium ◽  
Albumin Concentration ◽  
Total Calcium

Abstract Concentrations of total calcium and albumin were measured in serum specimens from 41 women at intervals before, during, and after 42 pregnancies. The albumin concentration decreased but the calcium decreased more slowly, so that the albumin-adjusted calcium concentration increased from conception to term. These findings, taken in conjunction with published observations of hypercalciuria, increased concentrations of 1,25-dihydroxycholecalciferol and calcitonin in serum, and decreased concentrations of intact parathyrin in serum, strongly suggest that maternal ionized calcium increases throughout normal pregnancy.

Effect of Hypocalcemia on Cardiac Function in Very-Low-Birth-Weight Preterm Neonates: Studies of Blood Ionized Calcium, Echocardiography, and Cardiac Effect of Intravenous Calcium Therapy

PEDIATRICS ◽  
1985 ◽  
Vol 76 (4) ◽  
pp. 543-550
Author(s):  
Pankaja S. Venkataraman ◽  
Don A. Wilson ◽  
Roger E. Sheldon ◽  
Radhakrishna Rao ◽  
Michael K. Parker
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Cardiac Function ◽  
Serum Calcium ◽  
Calcium Concentration ◽  
Very Low Birth Weight ◽  
Left Ventricular ◽  
Ionized Calcium ◽  
Total Calcium ◽  
Serum Total Calcium

Traditionally, in infants, a serum calcium value less than 7.0 mg/dL is considered to impair cardiac function. In very-low-birth-weight infants, we studied the hypotheses that decline in serum calcium to 6.0 mg/dL (1) would not impair cardiac function and (2) ionized calcium would remain greater than 3.0 mg/dL. We also evaluated the effect of calcium infusion on cardiac function. We studied 15 normokalemic and normonatremic infants whose birth weights were 822 to 1,450 g and were less than 32 weeks' gestation. When serum calcium declined to less than 6.0 mg/dL, 18 mg/kg of calcium as 5% calcium gluconate was infused for 10 minutes. Serum total calcium concentration, blood ionized calcium concentration, ECG, and M-mode echocardiogram were obtained on entry into the study, when the infants were hypocalcemic, immediately after treatment with calcium, and eight hours after treatment. Ionized calcium values were calculated based on serum total calcium and serum protein, and corrected calcium values were calculated based on serum total calcium, serum albumin, and blood pH. In all infants, serum calcium value declined to less than 7.0 and in eight infants to less than 6.0 mg/dL. Assessment of heart rate, systolic blood pressure, ejection fraction, left ventricular systolic time interval, right ventricular systolic time interval, fiber shortening index, and left ventricular mean velocity of circumferential fiber shortening showed no significant alteration from baseline during hypocalcemia or in association with intravenous slow bolus infusion of 18 mg/kg of calcium. In association with a decline in serum total calcium to as low as 6.0 mg/dL, whole blood ionized calcium was maintained at more than 3.0 mg/dL. Serum total calcium and calculated ionized calcium values correlated significantly with measured blood ionized calcium concentrations; however, these measures were not reliable predictors of blood ionized calcium. We speculate that the hypoproteinemia and hypoalbuminemia noted in these infants may result in relative protection of the blood ionized calcium in these infants. We suggest that in neonates with wide ranges in gestation, serum protein, and blood pH levels, total serum calcium and calculated ionized calcium values may be poor measures of derangement of calcium metabolism. Decline in total serum calcium concentration to 6.0 mg/dL was not associated with impaired cardiac function, and slow bolus calcium infusion in these hypocalcemic very-low-birth-weight infants neither improved nor impaired cardiac function.

Plasma Magnesium and Calcium Levels in Depressive Psychosis

1972 ◽  
Vol 120 (559) ◽  
pp. 683-684 ◽  
Author(s):  
G. J. Naylor ◽  
Laura W. Fleming ◽  
W. K. Stewart ◽  
H. B. McNamee ◽  
D. Le Poidevin
Keyword(s):  
Divalent Cation ◽  
Calcium Concentration ◽  
Depressive Illness ◽  
Plasma Calcium ◽  
Ionized Calcium ◽  
Total Plasma ◽  
Total Calcium ◽  
Before And After ◽  
Plasma Calcium Concentration ◽  
Plasma Magnesium

There have been reports of the association of alterations in the divalent cation content of plasma with depressive illness. Coirault and colleagues (1959) found increased ionized calcium levels despite decreased total plasma calcium concentration in patients recovered from depression. More recently, Frizel and colleagues (1969) have reported normal plasma ionized and total calcium levels both before and after recovery from depression.

A mathematical model of parathyroid hormone response to acute changes in plasma ionized calcium concentration in humans

2010 ◽  
Vol 226 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Rajiv P. Shrestha ◽  
Christopher V. Hollot ◽  
Stuart R. Chipkin ◽  
Claus P. Schmitt ◽  
Yossi Chait
Keyword(s):  
Mathematical Model ◽  
Parathyroid Hormone ◽  
Calcium Concentration ◽  
Ionized Calcium ◽  
Hormone Response ◽  
Acute Changes

scholarly journals Secretion and degradation of parathormone as a function of intracellular maturation of hormone pools

1979 ◽  
Vol 83 (3) ◽  
pp. 521-528 ◽  
Author(s):  
JJ Morrissey ◽  
DV Cohn
Keyword(s):  
Cyclic Amp ◽  
Half Life ◽  
Calcium Concentration ◽  
Hormone Secretion ◽  
Ionized Calcium ◽  
Dibutyryl Cyclic Amp ◽  
Low Calcium ◽  
High Calcium ◽  
Parathormone Secretion

The biosynthesis, processing, and secretion of parthormone and the effect of calcium on these processes were measured in dispersed porcine parthyroid cells incubated with [(35)S]methionine. Proparathormone was detected at 10 min, the earliest time measured, and was rapidly and apparently quantitatively converted to parathormone. The half-life of the prohomormone pool was 15 min. Secretion of parathormone was detected by 20 min. In pulse-chase experiments there was a period between 20 and 40 min during which the wave of newly-synthesized parathormone was secreted. After 40 min during little additional radioactive hormone was secreted, but dibutyryl cyclic AMP, an agent that can mobilize stored parathormone, when added to the incubation mixtures enhanced radioactive parathormone secretion but only after 60 min, although it increased net hormone secretion as determined by radioimmunoassay to the same extent at all times studied. When the ionized calcium concentration of the medium was lowered, more radioactive hormone was secreted at all times but the effect was greatest on that hormone that was synthesized less than 60 min previously ; however, net hormone secretion in contrast to radioactive hormone was enhanced equally at all intervals. These data could mean that the refractoriness to secretion of parathormone 40-60 min of age was related to maturation of secretory container preparatory to storage. Low calcium (0.5 mM) stimulated hormone secretion up to fivefold compared to high calcium (3.0 mM) but did not affect synthesis of parathormone or proparathormne or conversion of the latter to hormone. During processing at least 70 percent of the intracellular parathormone was lost, presumably through proteolysis and this degradation was greater at high calcium. These data have been interpreted in light of the concept that two secretable pools of parathormone exist within the parathyroid.

SERUM IONIZED CALCIUM IN NEWBORN INFANTS

PEDIATRICS ◽  
1972 ◽  
Vol 49 (6) ◽  
pp. 841-846
Author(s):  
David M. Brown ◽  
James Boen ◽  
Audrey Bernstein
Keyword(s):  
Biochemical Parameters ◽  
Newborn Infants ◽  
Ionized Calcium ◽  
Entire Group ◽  
Total Calcium ◽  
Serum Total Protein ◽  
Ionic Calcium ◽  
Serum Ionized Calcium ◽  
Absolute Concentrations ◽  
Positive Correlations

Relationships of serum ionized calcium with several biochemical parameters have been examined in newborn infants under 72 hours of age. Hypocalcemia was defined as plasma total calcium below 7.5 mg/100 ml. There was a linear correlation between plasma total calcium and ionized calcium in the entire group. Other positive correlations included: (1) plasma total calcium and serum total protein, albumin, and globulins and (2) absolute concentrations of ionic calcium and albumin. No statistically significant correlations were observed between either total or ionized calcium and serum phosphorus, percent ionized calcium, capillary pH, or Pco2. The derived values for serum ionic calcium from the McLean-Hastings nomogram did not correlate with the plasma ionic calcium as determined by the ion-specific electrode and may not be used in newborn infants to predict accurately the level of plasma ionic calcium.

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