scholarly journals Normocalcemia is maintained in mice under conditions of calcium malabsorption by vitamin D–induced inhibition of bone mineralization

2012 ◽  
Vol 122 (5) ◽  
pp. 1803-1815 ◽  
Author(s):  
Liesbet Lieben ◽  
Ritsuko Masuyama ◽  
Sophie Torrekens ◽  
Riet Van Looveren ◽  
Jan Schrooten ◽  
...  
JMS SKIMS ◽  
2011 ◽  
Vol 14 (2) ◽  
pp. 40-42
Author(s):  
Muzafar Maqsood Wani ◽  
Imtiaz Ahmed Wani

Major biologic function of activated vitamin D is to maintain normal blood levels of calcium and phosphorus, thus regulating bone mineralization. Research suggests that vitamin D may help in immunomodulation, regulating cell growth and 1,4 differentiation as well as some diverse unspecified functions. Overt vitamin D deficiency leads to hypocalcaemia, secondary hyperparathyroidism and increased bone turnover, which in prolonged and severe cases may cause rickets in children and osteomalacia in elderly.... JMS 2011;14(2):40-42


1962 ◽  
Vol 40 (4) ◽  
pp. 481-492
Author(s):  
J. G. Devlin ◽  
D. K. O'Donovan

ABSTRACT A case is reported of intermittent hypercalcaemia, hypophosphataemia and severe skeletal rarefaction with cystic changes. An occult calcium malabsorption was found. Fat, triolein and iron absorption and radiological examinations were normal. There was gross intestinal mucosal atrophy. She was shown to be in a state of negative calcium balance and this was reversed by vitamin D. A gluten-free diet also improved calcium absorption. It is postulated that the patient had severe secondary hyperparathyroidism as the skeleton reverted to normal after six months of medical treatment.


2002 ◽  
pp. 45-59 ◽  
Author(s):  
K W Colston ◽  
C M√∏rk Hansen

It is now well established that, in addition to its central role in the maintenance of extracellular calcium levels and bone mineralization, 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), the active form of vitamin D, also acts as a modulator of cell growth and differentiation in a number of cell types, including breast cancer cells. The anti-proliferative effects of 1,25(OH)(2)D(3) have been linked to suppression of growth stimulatory signals and potentiation of growth inhibitory signals, which lead to changes in cell cycle regulators such as p21(WAF-1/CIP1) and p27(kip1), cyclins and retinoblastoma protein as well as induction of apoptosis. Such studies have led to interest in the potential use of 1,25(OH)(2)D(3) in the treatment or prevention of certain cancers. Since this approach is limited by the tendency of 1,25(OH)(2)D(3) to cause hypercalcaemia, synthetic vitamin D analogues have been developed which display separation of the growth regulating effects from calcium mobilizing actions. This review examines mechanisms by which 1,25(OH)(2)D(3) and its active analogues exert both anti-proliferative and pro-apoptotic effects and describes some of the synthetic analogues that have been shown to be of particular interest in relation to breast cancer.


2021 ◽  
Vol 74 (7-8) ◽  
pp. 257-265
Author(s):  
Firdevs Ezgi Uçan Tokuç ◽  
Fatma Genç ◽  
Abidin Erdal ◽  
Yasemin Biçer Gömceli

Many systemic problems arise due to the side effects of antiepileptic drugs (AEDs) used in epilepsy patients. Among these adverse effects are low bone mineral density and increased fracture risk due to long-term AED use. Although various studies have supported this association with increased risk in recent years, the length of this process has not been precisely defined and there is no clear consensus on bone density scanning, intervals of screening, and the subject of calcium and vitamin D supplementation. In this study, in accordance with the most current recommendations, our applications and data, including the detection of possible bone mineralization disorders, treatment methods, and recommendations to prevent bone mineralization disorders, were evaluated in epilepsy patients who were followed up at our outpatient clinic. It was aimed to draw attention to the significance of management of bone metabolism carried out with appropriate protocols. Epilepsy patients were followed up at the Antalya Training and Research Hospital Department of Neurology, Epilepsy Outpatient Clinic who were at high risk for osteoporosis (use of valproic acid [VPA] and enzyme-inducing drugs, using any AED for over 5 years, and postmenopausal women) and were evaluated using a screening protocol. According to this protocol, a total of 190 patients suspected of osteoporosis risk were retrospectively evaluated. Four patients were excluded from the study due to secondary osteoporosis. Of the 186 patients who were included in the study, 97 (52.2%) were women and 89 (47.8%) were men. Prevalence of low bone mineral density (BMD) was 42%, in which osteoporosis was detected in 11.8% and osteopenia in 30.6% of the patients. Osteoporosis rate was higher at the young age group (18-45) and this difference was statistically significant (p=0.018). There was no significant difference between male and female sexes according to osteoporosis and osteopenia rates. Patients receiving polytherapy had higher osteoporosis rate and lower BMD compared to patients receiving monotherapy. Comparison of separate drug groups according to osteoporosis rate revealed that osteoporosis rate was highest in patient groups using VPA+ carbamazepine (CBZ) (29.4%) and VPA polytherapy (19.4%). Total of osteopenia and osteoporosis, or low BMD, was highest in VPA polytherapy (VPA+ non-enzyme-inducing AED [NEID]) and CBZ polytherapy (CBZ+NEID) groups, with rates of 58.3% and 55.1%, respectively. In addition, there was no significant difference between drug groups according to bone metabolism markers, vitamin D levels, and osteopenia-osteoporosis rates. Assuming bone health will be affected at an early age in epilepsy patients, providing lifestyle and diet recommendations, avoiding polytherapy including VPA and CBZ when possible, and evaluating bone metabolism at regular intervals are actions that should be applied in routine practice.


2012 ◽  
Vol 82 (5) ◽  
pp. 342-347 ◽  
Author(s):  
Ibrahim Elmadfa ◽  
Alexa L. Meyer

Vitamins are essential nutrients for many body functions and particularly important during growth. Adequate supply in pregnancy and in early infancy is therefore crucial, but there is still a lack of knowledge about the needed amounts of vitamins of children older than six months and also during pregnancy. Recommendations for intake levels are generally derived by extrapolation from data for infants based in turn on the contents in breast milk and those for adults. A vitamin of particular importance in pregnancy is folic acid due to its role in the development of the brain and nerve system and the prevention of fetal neural tube defects (NTD). Mandatory fortification of flour and certain other grain products in many countries has been associated with a reduction in NTD incidence. However, other deficiencies or suboptimal status of B vitamins, especially B6 and B12 have been repeatedly reported in pregnant women also in high-income countries. Vitamin A is one of the three most critical micronutrients globally and pregnant women and young children are especially vulnerable to deficiencies. Night blindness, anemia, and immunodeficiency are major consequences of inadequate supply in these populations. Much attention has recently been accorded vitamin D that is also critical in pregnant women and young children for instance because of its involvement in bone mineralization but also its more recently discovered immune-modulating function that is thought to prevent development of autoimmune diseases like diabetes mellitus type I. A healthy balanced diet provides the best basis for optimal pregnancy outcome, lactation performance, and complementary feeding. However, supplements or fortified foods may be needed to cover the high requirements especially of critical vitamins such as vitamin D and folic acid and to correct unfavorable dietary patterns in women or to adapt foods to the needs of young children.


2007 ◽  
Vol 96 (7) ◽  
pp. 969-974 ◽  
Author(s):  
Jacques Rigo ◽  
Catherine Pieltain ◽  
Bernard Salle ◽  
Jacques Senterre

Endocrinology ◽  
2001 ◽  
Vol 142 (1) ◽  
pp. 494-497 ◽  
Author(s):  
Ritsuko Masuyama ◽  
Yumi Nakaya ◽  
Shinya Tanaka ◽  
Hiroshi Tsurukami ◽  
Toshitaka Nakamura ◽  
...  

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