A Comparative Study of Measured and Calculated Ionized Calcium in Plasma

Calcium as a nutrient is most commonly associated with the formation and metabolism of Bone. Over 99 percent of total Body calcium is found as calcium hydroxyapatite. Ionized calcium is measured by ion selective electrodes. It is also calculated from albumin and globulin values using an appropriate formula. In this study was we will compare measured and calculated ionized calcium in plasma. Material and method : The comparative descriptive study was conducted in Department of Biochemistry of Guru Gobind Singh Medical College and Hospital, Faridkot. 50 patients of arterial blood were enrolled for study. Result: A total of 50 simultaneous arterial blood samples were obtained from 50 patients. Mean age of 45.52±17.45 years and range 18-84 years. Maximum numbers (40%) of patients were from the age group of 34-50 years followed by (24%) in the age group of 18 - 33 years A statistically significant correlation was found between measured and ionized calcium with p value 0.002 and r value 0.418. The difference between measured and Calculated ionized calcium was 0.24mmol/l with p value <0.001 (95% CI of 0.17 – 0.30) which was statistically highly significant. Conclusion; The values of measured and calculated ionized calcium are correlated but there is significant difference in their mean value. Moreover calculated calcium shows significant correlation with total protein and albumin so it is not a reliable indicator in conditions where protein levels are altered.

Vitamin D deficiency cardiomyopathy in Scotland: a retrospective review of the last decade

ObjectiveTo determine the incidence, demography and prognosis of vitamin D deficiency dilated cardiomyopathy (DCM) in Scotland over the last decade.Study designA retrospective review of cases of vitamin D deficiency DCM presenting to a national paediatric cardiac centre between 1 January 2008 and 1 January 2018. The departmental database and electronic and paper case notes were used to identify patients and extract data.ResultsSix patients were identified (three male), three of whom were Caucasian. Median age at presentation was 206 days (range 2–268.) All six patients had high serum parathyroid hormone levels (median 45 pmol/L, range 27–120 pmol/L), a sensitive marker of total body calcium deprivation secondary to vitamin D deficiency. All patients demonstrated clinical and echocardiographic improvement following high dose vitamin D treatment. No patients required cardiac transplant, and only one patient required extracorporeal life support as a bridge to recovery. After an initial improvement, one child died at 5 months as a result of respiratory infection. Three patients lived within some of the most deprived areas in Scotland.ConclusionsThis case series demonstrates a previously unreported demographic in Scotland, as 50% of cases presented in Caucasian children. Although vitamin D deficiency DCM is relatively rare, it is wholly preventable. Our study confirms that vitamin D deficiency cardiomyopathy is reversible with prompt identification and supplementation. The current implementation of public health policy in the UK is failing to prevent children from developing the most severe manifestation of vitamin D deficiency.

Reducing Pup Litter Size Alters Early Postnatal Calcium Homeostasis and Programs Adverse Adult Cardiovascular and Bone Health in Male Rats

The in utero and early postnatal environments play essential roles in offspring growth and development. Standardizing or reducing pup litter size can independently compromise long-term health likely due to altered milk quality, thus limiting translational potential. This study investigated the effect reducing litter size has on milk quality and offspring outcomes. On gestation day 18, dams underwent sham or bilateral uterine vessel ligation surgery to generate dams with normal (Control) and altered (Restricted) milk quality/composition. At birth, pups were cross-fostered onto separate dams with either an unadjusted or reduced litter size. Plasma parathyroid hormone-related protein was increased in Reduced litter pups, whereas ionic calcium and total body calcium were decreased. These data suggest Reduced litter pups have dysregulated calcium homeostasis in early postnatal life, which may impair bone mineralization decreasing adult bone bending strength. Dams suckling Reduced litter pups had increased milk long-chain monounsaturated fatty acid and omega-3 docosahexaenoic acid. Reduced litter pups suckled by Normal milk quality/composition dams had increased milk omega-6 linoleic and arachidonic acids. Reduced litter male adult offspring had elevated blood pressure. This study highlights care must be taken when interpreting data from research that alters litter size as it may mask subtle cardiometabolic health effects.

The effect of a low-protein diet in pregnancy on offspring renal calcium handling

Low birth weight humans and rats exposed to a low-protein diet in utero have reduced bone mineral content. Renal calcium loss during the period of rapid skeletal growth is associated with bone loss. Because young rats exposed to low protein display altered renal function, we tested the hypothesis that renal calcium excretion is perturbed in this model. Pregnant Wistar rats were fed isocalorific diets containing either 18% (control) or 9% (low) protein throughout gestation. Using standard renal clearance techniques, Western blotting for renal calcium transport proteins, and assays for Na+-K+-ATPase activity and serum calcitropic hormones, we characterized calcium handling in 4-wk-old male offspring. Histomorphometric analyses of femurs revealed a reduction in trabecular bone mass in low-protein rats. Renal calcium (control vs. low protein: 10.4 ± 2.1 vs. 27.6 ± 4.5 nmol·min−1·100 g body wt−1; P < 0.01) and sodium excretion were increased, but glomerular filtration rate was reduced in low-protein animals. Total plasma calcium was reduced in low-protein rats ( P < 0.01), but ionized calcium, serum calcitropic hormone concentrations, and total body calcium did not differ. There was no significant change in plasma membrane Ca2+-ATPase pump, epithelial calcium channel, or calbindin-D28K expression in low-protein rat kidneys. However, Na+-K+-ATPase activity was 36% lower ( P < 0.05) in low-protein rats. These data suggest that the hypercalciuria of low-protein rats arises through a reduction in passive calcium reabsorption in the proximal tubule rather than active distal tubule uptake. This may contribute to the reduction in bone mass observed in this model.

Uteroplacental restriction in the rat impairs fetal growth in association with alterations in placental growth factors including PTHrP

During pregnancy, parathyroid hormone-related protein (PTHrP) is one of many growth factors that play important roles to promote fetal growth and development, including stimulation of placental calcium transport. Angiotensin II, acting through the AT1a receptor, is also known to promote placental growth. We examined the effects of bilateral uterine artery and vein ligation (restriction), which mimics placental insufficiency in humans, on growth, intrauterine PTHrP, placental AT1a, and pup calcium. Growth restriction was surgically induced on day 18 of pregnancy in Wistar-Kyoto female rats by uterine vessel ligation. Uteroplacental insufficiency reduced fetal body weight by 15% and litter size ( P < 0.001) compared with the control rats with no effect on placental weight or amniotic fluid volume. Uteroplacental insufficiency reduced placental PTHrP content by 46%, with increases in PTHrP (by 2.6-fold), parathyroid hormone (PTH)/PTHrP receptor (by 11.6-fold), and AT1a (by 1.7-fold) relative mRNA in placenta following restriction compared with results in control ( P < 0.05). There were no alterations in uterine PTHrP and PTH/PTHrP receptor mRNA expression. Maternal and fetal plasma PTHrP and calcium concentrations were unchanged. Although fetal total body calcium was not altered, placental restriction altered perinatal calcium homeostasis, as evidenced by lower pup total body calcium after birth ( P < 0.05). The increased uterine and amniotic fluid PTHrP ( P < 0.05) may be an attempt to compensate for the induced impaired placental function. The present study demonstrates that uteroplacental insufficiency alters intrauterine PTHrP, placental AT1a expression, and perinatal calcium in association with a reduction in fetal growth. Uteroplacental insufficiency may provide an important model for exploring the early origins of adult diseases.

Calcium and Bone Health in Infants

Osteopenia, rickets, and fractures from nutrient deficiencies can occur during infancy, particularly in preterm infants. Bone mass accretion during the first year of life is equal to or greater than that achieved at any other stage of life, including adolescence. Optimizing calcium and bone status during infancy can have immediate benefits in maintaining calcium homeostasis and preventing disturbances in bone mineralization and can provide long-term benefits by helping infants to later reach their maximum genetic potential for peak bone mass, a prerequisite for the prevention of osteoporosis and its complications. Dietary calcium requirements during infancy generally reflect the need to achieve normal growth and bone mineralization because 99 percent of total body calcium is present in the skeleton. Knowledge of physiologic factors that determine infant calcium requirements and the bioavailability of calcium from various dietary sources is important to ensuring bone health during infancy. Also key are the practical issues related to optimizing calcium nutriture in infants born at term and prematurely.