Browsing by Author "Rajasree, S"

Now showing 1 - 5 of 5
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    1,25-dihydroxyvitamin D-3 receptor is upregulated in aortic smooth muscle cells during hypervitaminosis D
    (LIFE SCIENCES, 2002)
    Several studies have demonstrated that excess of vitamin D-3 is toxic particularly to vascular tissues. A notable pathological feature is arterial calcification. The nature of the toxic metabolite in hypervitaminosis D and the pathogenesis of arterial calcification are not clearly understood. The present study was undertaken to explore whether arterial calcification is a sequel of increased calcium uptake by arterial smooth muscle mediated by up regulation of vitamin D receptor in the cells in response to elevated circulating levels of vitamin D-3 in serum. The experimental study was performed in 20 New Zealand white female rabbits aged 6 months. Animals in the test group were injected 10,000 IU of cholecalciferol intramuscularly twice a week for one month. Six control animals were given intra-muscular injections of plain cottonseed oil. Animals were sacrificed and aortas were examined for pathological lesions, 1,25-dihyroxyvitamin D-3 (1,25(OH)(2) D-3) receptor levels and Ca-45 uptake in smooth muscle cells. Serum samples collected at intervals were assayed for levels of 25-OH-D-3 and calcium. The results showed that in animals given injections of cholecalciferol, serum levels of 25-OH-D-3 Were elevated. In four of these animals calcification and aneurysmal changes were seen in the aorta. Histological lesions comprised of fragmentation of elastic fibers as well as extensive loss of elastic layers. 1,25(OH)(2) D-3 receptor levels were up regulated and Ca-45 uptake enhanced in aortas of animals which were given excessive vitamin D-3. The evidences gathered suggest that excess vitamin D is arteriotoxic and that the vitamin induces arterial calcification through up regulation of 1,25(OH)(2)D-3 receptor and increased calcium uptake in smooth muscle cells of the arteries. (C) 2002 Elsevier Science Inc. All rights reserved.
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    Elevated serum levels of 25-hydroxyvitamin D-3 in outdoor workers of South India
    (CURRENT SCIENCE, 1999) Rajasree, S; Kutty, VR; Sreenivasan, K; Kartha, CC
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    Nutritional status of children in Kerala.
    (Indian pediatrics, 1994)
    Nutritional status of children in two poor communities was studied using conventional anthropometric techniques. A total of 944 children, of which 246 boys and 242 girls in coastal area and 213 boys and 249 girls in the non-coastal area formed the study group. With measurements of height and weight, the prevalence of various forms of growth retardation was determined in two communities. Inspite of better food intake, the rural coastal children exhibited poorer nutritional status mainly because of environmental deprivation.
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    Serum 25-hydroxyvitamin D-3 levels are elevated in South Indian patients with ischemic heart disease
    (EUROPEAN JOURNAL OF EPIDEMIOLOGY, 2001)
    Several lines of evidence point to a possible relationship between vitamin D and cardiovascular disease. Animal experiments and observational studies in humans suggest vitamin D to be arteriotoxic and an association of high intake of vitamin D with increased incidence of ischemic heart disease (IHD). The major source of vitamin D in adults is vitamin D synthesized in the skin through exposure to the sun. In tropical environment there is a possibility of high level of solar exposure and enhanced serum levels of vitamin D in the population. We explored the relation between serum level of 25-hydroxyvitamin D-3 and IHD in a case-control study involving 143 patients with either angiographic evidence of coronary artery disease or patients with acute myocardial infarction and 70 controls, all men in the age group of 45-65 years. Fasting blood samples were collected, serum separated and serum levels of 25-hydroxyvitamin D-3 was measured by protein binding radioligand assay. Serum levels of cholesterol, triglyceride, calcium, magnesium and inorganic phosphate were also determined. Prevalences of diabetes, hypertension and smoking history were noted. Statistical comparisons of variables between cases and controls were done using chi(2)-tests. Multivariate logistic regression analysis was done to examine the association of IHD with serum levels of 25-hydroxyvitamin D-3 controlling for selected variables. Serum levels of 25-hydroxyvitamin D-3, calcium, inorganic phosphate, total cholesterol, low density lipoprotein and triglycerides were elevated in a higher proportion of patients, compared to controls. Serum levels of 25-OH-D-3 above 222.5 nmol/l (89 ng/ml) was observed in 59.4% of cases compared to 22.1% in controls (p < 0.001; unadjusted odds ratio (OR): 5.17; 95% confidence interval (CI): 2.62-10.21). When controlled for age and selected variables using the multivariate logistic regression, the adjusted OR relating elevated serum 25-hydroxyvitamin D-3 levels ( greater than or equal to222.5 nmol/l, greater than or equal to89 ng/ml) and IHD is 3.18 (95% CI: 1.31-7.73). Given the evidences for the arteriotoxicity of vitamin D, further investigations are warranted to probe whether the elevated serum levels of 25-hydroxyvitamin D-3 observed in patients with IHD in a tropical environment has any pathogenic significance.
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    Vitamin D and atherosclerosis: A noteworthy link
    (FRONTIERS IN CARDIOVASCULAR HEALTH, 2003) Kartha, CC; Rajasree, S
    A number of studies indicate a possible relationship of vitamin D with atherosclerotic diseases. Jim Moon, Bandy and Davison in 1992 observed that the epidemic of ischemic heart disease in North America paralleled the increased use of vitamin D and decreased availability of dietary magnesium. Linden had earlier found a direct correlation of dietary intake of the vitamin with susceptibility for myocardial infarction and suspected that the known hypercholestrolemic effect of the vitamin may be the mechanism. Animal experiments suggest vitamin D to be arteriotoxic. Massive doses of vitamin D induce atherosclerotic lesions in a number of animal species. Lesions similar to those in humans are found when animals are fed hypercholestrolemic diet, given large doses of vitamin D and exposed to nicotine. The major source of vitamin D in adults is vitamin D synthesized in the skin through exposure to the sun. In tropical environment there is a possibility of high level of solar exposure and enhanced serum levels of vitamin D in the population. We explored the relation between serum level of 25-hydroxy vitamin D-3 and ischemic heart disease in a case-control study involving 143 patients with either angiographic evidence of coronary artery disease or patients with acute myocardial infarction and 70 controls, all men in the age group of 45-65 years. Serum levels of 25-hydroxy vitamin D-3, calcium, inorganic phosphate, cholesterol, low-density lipoprotein and triglycerides were elevated in a higher proportion of patients, compared to controls. Serum level of 25-OH-D-3 above 222.5 nmol/L (89 ng/ml) was observed in 59.4% of cases compared to 22.1% in controls (p < 0.001). Elevated serum 25 hydroxy vitamin D-3 levels (greater than or equal to222.5 nmol/L, greater than or equal to89 ng/ml) are associated with a 3.18 fold (95% confidence interval of Odds Ratio: 1.31-7.73) increased rate of ischemic heart disease. Considering the causal relation among calcium, vitamin D and arteriotoxicity, further investigations are warranted to probe whether the elevated serum levels of 25OH-vitamin D-3 observed in patients with ischemic heart disease in a tropical environment has any pathogenic significance.