A Model of Calcium Homeostasis in the Rat.

A Model of Calcium Homeostasis in the Rat. Am J Physiol Renal Physiol. 2016 Jun 29;:ajprenal.00230.2016 Authors: Granjon D, Bonny O, Edwards A Abstract We developed a model of calcium homeostasis in the rat in order to better understand the impact of dysfunctions such as primary hyperparathyroidism and vitamin D deficiency on calcium balance. The model accounts for the regulation of calcium intestinal uptake, bone resorption, and renal reabsorption by parathyroid hormone (PTH), vitamin D3, and Ca2+ itself. It is the first such model to incorporate recent findings regarding the role of the calcium sensing receptor (CaSR) in the kidney, the presence of a rapidly exchangeable pool in bone, and the delayed response of vitamin D3 synthesis. Accounting for two (fast and slow) calcium storage compartments in bone allows the model to properly predict the effects of bisphophonates on the plasma levels of Ca2+ ([Ca2+]p), PTH, and vitamin D3. Our model also suggests that Ca2+ exchange rates between plasma and the fast pool vary with both sex and age, allowing [Ca2+]p to remain constant in spite of sex- and age-based hormonal and other differences. Our results suggest that the inconstant hypercalciuria that is observed in primary hyperparathyroidism can be attributed in part to counterbalancing effects of PTH and CaSR in the kidney. Our model also correctly predicts that calcimimetic agents such as Cinacalcet bring down [Ca2+]p to within its normal range in primary ...
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Tags: Am J Physiol Renal Physiol Source Type: research

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Conclusions: Contrary to our hypothesis, we found an inverse association between serum PTH and Barrett’s esophagus. Validation of the finding and the mechanism of that association deserves further study.
Source: Journal of Clinical Gastroenterology - Category: Gastroenterology Tags: ALIMENTARY TRACT: Original Articles Source Type: research
Abstract BACKGROUND: Low vitamin D (VD) is not always followed by the development of secondary hyperparathyroidism (SHPT). The study aimed to assess the prevalence of SHPT and functional hypoparathyroidism (FHPT) in relation to VD deficiency/insufficiency and factors predisposing to parathyroid hormone (PTH) response in old and very-old Caucasians. METHODS: A sub-study of the cross-sectional PolSenior project analyzed serum 25(OH)D, intact PTH (iPTH) and C-terminal fibroblast growth factor 23 (cFGF23) concentrations in 3472 (1658 women) individuals aged ≥65 years. SHPT was defined as iPTH concentrationâ€...
Source: Experimental Gerontology - Category: Geriatrics Authors: Tags: Exp Gerontol Source Type: research
AbstractThis case describes a 103-year-old lady who presented from home with an incidental diagnosis of a left femoral fracture. She had no history of trauma and denied pain. She had a known diagnosis of osteoporosis, and sustained a fracture of the contralateral femur aged 93 which was managed conservatively. She was bed-bound with fixed contractures, poor oral intake and was non-compliant with prescribed calcium/vitamin D supplementation. Clinical biochemical measurements showed severe vitamin D deficiency and mild hypocalcaemia. Secondary hyperparathyroidism in the setting of an inappropriately normal phosphate suggeste...
Source: The Journal of Nutrition, Health and Aging - Category: Nutrition Source Type: research
We present a rare case of a previously healthy 16-year-old boy who sustained simultaneous bilateral femoral neck fractures after a single first-time seizure episode. He was diagnosed to have severe vitamin D deficiency and secondary hyperparathyroidism. Symptomatic hypocalcemia was the cause of seizures. Both fractures were treated surgically and united at 3 months. Bilateral femoral neck fractures after seizures are very rare, especially in children. Severe vitamin D deficiency may cause seizures and also weakening of bone, predisposing to fractures without significant trauma. We recommend that paediatric cases of femoral...
Source: Journal of Pediatric Orthopaedics B - Category: Orthopaedics Tags: PELVIS & HIP Source Type: research
AbstractHeart failure (HF) with reduced ejection fraction (HFrEF) presents as the severest phenotype on the spectrum of HF. Although great progress has been made with respect to its treatment over the past 3 decades, morbidity and mortality remain high, posing a big burden on human health. Recent evidence suggests vitamin D has a critical role in maintaining heart health through activation of the vitamin D receptor expressed in cardiomyocytes, and vitamin D deficiency may be implicated in the pathophysiology of HFrEF through activation of the renin-angiotensin system, impaired calcium handling, exaggerated inflammation, se...
Source: American Journal of Cardiovascular Drugs - Category: Cardiology Source Type: research
AbstractPurposeParathyroid hormone (PTH) concentrations are routinely measured in the diagnosis and management of bone and kidney diseases, but reference ranges can be overestimated if determined in otherwise healthy individuals for whom vitamin D deficiency was not evaluated. We establish PTH reference ranges in apparently healthy, normocalcemic, normophosphatemic individuals categorized by 25-hydroxyvitamin D (25(OH)D) status using the Elecsys® PTH (cobas e 601) and Elecsys® Vitamin D total II electrochemiluminescence immunoassays (cobas e 411).MethodsThis prospective, non-interventional study measured PTH in ser...
Source: Journal of Endocrinological Investigation - Category: Endocrinology Source Type: research
Publication date: Available online 28 June 2019Source: Diabetes &Metabolic Syndrome: Clinical Research &ReviewsAuthor(s): Ayman Aly Seddik, Alaaeldin Bashier, Amna Khalifa Alhadari, Fakhryia AlAlway, Hind Hassan Alnour, Azza Abdulaziz Bin Hussain, Andrew Frankel, Mohammed Jaffer RaileyAbstractChronic kidney disease is associated with accumulation of uremic toxins that increases insulin resistance which will lead to blunted ability to suppress hepatic gluconeogenesis and reduce peripheral utilization of insulin. CKD patients fail to increase insulin secretion in response to insulin resistance because of acidosis, 1,...
Source: Diabetes and Metabolic Syndrome: Clinical Research and Reviews - Category: Endocrinology Source Type: research
Authors: Wajda J, Åšwiat M, Owczarek AJ, Brzozowska A, Olszanecka-Glinianowicz M, Chudek J Abstract Background: Vitamin D (VD) deficiency is considered an independent risk factor for death due to cardiovascular events including ischemic stroke (IS). We assessed the hypothesis that decreased levels of 25-hydroxyvitamin D (25-OH-D) are associated with increased risk of mortality in patients with IS. Methods: Serum 25-OH-D, intact parathyroid hormone (iPTH), and intact fibroblast growth factor 23 (iFGF23) levels were assessed in serum of 240 consecutive patients admitted within the 24 hours after the onset of IS. ...
Source: Disease Markers - Category: Laboratory Medicine Tags: Dis Markers Source Type: research
Physiologic changes during pregnancy include calcium, phosphate, and calciotropic hormone status. Calcium metabolic disorders are rare in pregnancy and management with close calcium and vitamin D control and supplementation. Primary hyperparathyroidism is mostly asymptomatic and does not affect conception or pregnancy. It requires control of plasma calcium levels. Surgical intervention may be indicated. Data on severe cases are missing. Osteoporosis in or before pregnancy is rare but usually diagnosed from fractures. Medical treatment other than supplementation is contraindicated. Vitamin D deficiency is common and may aff...
Source: Endocrinology and Metabolism Clinics of North America - Category: Endocrinology Authors: Source Type: research
​BY HABIR MANDAIR; KEYUR KURANI; &KHALID MALIK, MDA 62-year-old obese woman with end-stage renal disease (ESRD) who was on hemodialysis, hypertension, diabetes mellitus, and chronically elevated serum calcium levels presented to the ED with altered mental status. Nursing home staff stated that she was unable to answer questions coherently and seemed confused.Her vitals were within normal limits except for a body temperature of 99.9°F. Several necrotic lesions of various sizes were found on her left and right buttocks and the medial aspects of both thighs. The patient also had severe necrosis of the third finger o...
Source: The Case Files - Category: Emergency Medicine Tags: Blog Posts Source Type: research
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