Search

Dysregulated calcium homeostasis is common in chronic kidney disease and causally associated with disorders of bone mineralization. However, radiological measures and biomarkers do not allow accurate evaluation of bone calcium balance. Non-radioactive calcium isotopes, 42Ca and 44Ca, are present in our diet and sequestered into body compartments following principles of kinetic isotope fractionation. Isotopically light 42Ca is preferentially incorporated into bone, while heavier 44Ca is excreted. The ratio (44/42Caserum) increases when bone formation exceeds resorption and vice versa, reflecting bone calcium balance. We measured these calcium isotopes by inductively coupled plasma mass-spectrometry in blood, urine and feces of 42 children with chronic kidney disease and 92 receiving dialysis therapy. We compared the isotope ratios with bone biomarkers and determined total bone mineral content by dual-energy x-ray absorptiometry and peripheral quantitative CT expressed as age-adjusted z-scores. The 44/42Caserum ratio positively correlated with serum calcium, 25-hydroxyvitamin D and alkaline phosphatases and inversely with serum parathyroid hormone and other bone resorption markers. The 44/42Caserum ratio positively correlated with age-adjusted z-scores of tibial trabecular bone mineral density and total bone mineral content measured by peripheral quantitative CT, and hip bone mineral density measured by dual-energy X-ray absorptiometry. Significant and independent predictors of total bone mineral content, measured by, were the 44/42Caserum ratio and parathyroid hormone. The 44/42Caserum ratio, repeated after four weeks, highly correlated with baseline values. When adjusted for calcium-containing medications and kidney impairment, the 44/42Caserum ratio in patients receiving dialysis was 157% lower than that of age-matched children and 29% lower than levels in elderly women with osteoporosis, implying significantly lower bone mineral content. Thus, calcium isotope rati

Calcium is an important nutrient but also contributes to the texture, taste and functionality of most dairy products. The balance between micellar and free calcium in curd and serum phase during direct acidification of bovine milk was studied by changing organic acid type, pH and acidification temperature. Concentration of free calcium increased with decreasing pH and increasing temperature. Citric acid was more efficient than lactic acid at lowering free calcium concentration, while temperature effect was larger for acidification with lactic acid. These findings are rationalized by the stronger binding of calcium to citrate compared to lactate with an almost athermal binding for citrate and an endothermal binding for lactate. Curd yield decreased by decreasing pH as solubilization of colloidal calcium phosphate causes loss of minerals into the serum phase decreasing the concentration of both calcium and phosphate left in the curd, while acidification temperature had little effect on curd yield. These results are important to improve yield and tailor the properties and functionality of dairy products, such as for example Mozzarella cheese.

Agnieszka Makowka, Michal Nowicki Department of Nephrology, Hypertension and Kidney Transplantation, Medical University of Lodz, Lodz, PolandCorrespondence: Michal NowickiDepartment of Nephrology, Hypertension and Kidney Transplantation, Medical University of Lodz, Central University Hospital, Pomorska Str 251, Lodz, 92-213, PolandTel +48 42 2014400Fax +48 42 2014401Email nefro@wp.plObjective: Opposite to lanthanum carbonate (LC), sevelamer hydrochloride (SH) may increase intestinal calcium absorption. The study compared the effects of LC and SH on serum and urine phosphate and calcium, and on hormones regulating mineral-bone metabolism.Patients and Methods: A prospective randomized crossover study included 34 patients with eGFR < 60 mL/min. A single oral dose of LC (1,000 mg) or SH (2,400 mg) was administered in random order 15 minutes after a standardized meal fortified with 5 g calcium carbonate. Serum calcium, phosphate, and parathormone were measured before and 3, 6, 12, and 24 hours after each medication. Bone alkaline phosphatase (BAP), sclerostin, calcitriol, and FGF-23 were measured at baseline and after 12 and 24 hours. A 24-hour calcium and phosphate excretion was measured after each drug.Results: Serum calcium increased 3 and 6 hours after SH then returned to baseline. After LC calcium was unchanged for up to 3 hours then transiently increased and eventually returned to baseline. The area under curve (AUC) of serum calcium for 12 hours after SH was larger than after LC (p=0.04). Serum phosphate decreased after each drug with a nadir 3 hours post-SH and 6 hours post-LC. AUC of serum phosphate was similar after both medications. PTH decreased transiently after both drugs. BAP did not change. FGF-23 was constant for the first 12 hours but later decreased after each drug.Conclusion: A 2,400 mg SH and 1,000 mg LC are similarly effective in lowering serum phosphate in CKD, but LC induce in less intestinal calcium absorption after a meal. The trial was regis

Aim To assess the efficacy, safety and calcium balance of a membrane based regional citrate anticoagulation plasma exchange protocol. Methods This was an observational, prospective, single centre study of membrane separation plasma exchange using regional citrate anticoagulation. It was performed using a fixed dose pre‐filter citrate infusion that was based on the plasma flow rate. Patients received a post filter calcium infusion that was modified during treatment based on systemic ionized calcium monitoring. Post filter ionized calcium was not assessed. Safety and efficacy were assessed by extraction of clinical events and laboratory data contemporaneously recorded in electronic health records. Results Thirty‐six sessions in five patients were performed. No patients developed symptomatic hypocalcaemia, and no patient had a recorded ionized calcium below 0.81 mmol/L. Filter clotting occurred in two sessions. The mean net calcium gained was 9.6 ± 1.8 mmol per session. Conclusion Regional citrate anticoagulated membrane separation plasma exchange can be performed safely and effectively without the need for post filter ionized calcium monitoring. The algorithm employed resulted in a net calcium gain.

Item does not contain fulltext, BACKGROUND: Identification of the underlying causes of secondary hyperparathyroidism (SHPT) in individual patients on hemodialysis (HD) is hampered by the lack of clinically reliable information on calcium balance. The aim of this study was to assess calcium balance during HD sessions with a method that is applicable in day-to-day practice. METHODS: Plasma ionized calcium (pCa2+) and parathyroid hormone (PTH) were measured at the beginning and end of HD to evaluate calcium fluxes in 23 patients on a dialysate calcium (DCa) concentration of 1.25 mmol/L. RESULTS: HD with a DCa of 1.25 mmol/L caused a decrease in pCa2+ from 1.15 +/- 0.01 mmol/L to 1.09 +/- 0.01 mmol/L (p<0.0001) and increased plasma PTH from 26.7 +/- 1.8 pmol/L to 37.0 +/- 2.9 pmol/L (p<0.0001). The changes in pCa2+ were inversely related to the predialysis pCa2+ levels (R2 = 0.86, p<0.001). Patients with a predialysis pCa2+ >1.06 mmol/L had a calcium efflux, whereas those with a predialysis pCa2+ <1.06 mmol/L had a calcium influx during HD. CONCLUSION: The results suggest that measurement of pCa2+ and PTH at the beginning and the end of HD provides useful information about calcium fluxes in individual patients. Further validation of this approach is warranted.

Radboud Unversity Nijmegen, Animal Physiology, 21 juni 2007, Promotor : Flik, G., Contains fulltext : 30013.pdf (publisher's version ) (Open Access), The research aimed to elucidate hypercalcemic regulation in juvenile sea bream confronted with an experimentally induced limited access to environmental calcium. The principle to restrict sea bream in its access to calcium in water and diet was to activate hypercalcemic regulatory factors such as PTHrP and study the role of PTHrP in regulation of the calcium balance. Correlations between plasma ionic calcium and plasma PTHrP and between plasma PTHrP and pituitary gland pthrp mRNA expression show that PTHrP, as an endocrine factor, is important in maintenance of fish plasma calcium balance. Variation in the need for calcium (bone mineralisation, vitellogenesis) or the availability of environmental calcium (limited concentrations in water or diet) urge the endocrine system to respond rapidly to regulate the ionic calcium level. PTHrP-involvement in skeletal and scale physiology has been established in bone mineralisation (during growth and development) and in calcium reabsorption from the scales, when processes as vitellogenesis require extra calcium. The very strict control of calcium homeostasis (by a plethora of endocrines: PTHrP, PTH, PRL, stanniocalcin, calcitonin, E2, calcitriol, cortisol, etc.) and plasma ionic calcium levels through swift endocrine adjustments make this a complicated field of research. However, a new array of paradigms with a key role for fish shows involvement of PTHrP in vitellogenesis, cortisol production, Mrp2 activity and melatonin synthesis. Such studies will rapidly expand our knowledge on this pleiotropic hormone. They show that the calciotropic actions of PTHrP concern organismal as well as cellular physiological phenomena. Studies on fish give insight in original functions of PTHrP-regulated processes and, once again, show the power of comparative endocrinology.

Contains fulltext : 35554.pdf ( ) (Open Access), Juvenile gilthead sea bream were exposed to diluted seawater (2.5 per thousand salinity; DSW) for 3 h or, in a second experiment, acclimated to DSW and fed a control or calcium-deficient diet for 30 days. Branchial Ca(2+) influx, drinking rate and plasma calcium levels were assessed. Sea bream plasma parathyroid hormone related protein (sPTHrP) was measured, and mRNAs of pthrp, its main receptor, pth1r, and the calcium-sensing receptor (casr) were quantified in osmoregulatory tissues and the pituitary gland. When calcium is limited in water or diet, sea bream maintain calcium balance; however, both plasma Ca(2+) and plasma sPTHrP concentrations were lower when calcium was restricted in both water and diet. Positive correlations between plasma sPTHrP and plasma Ca(2+) (R(2)=0.30, N=39, P<0.05), and plasma sPTHrP and body mass of the fish (R(2)=0.37, N=148, P<0.001) were found. Immunoreactive sPTHrP was demonstrated in pituitary gland pars intermedia cells that border the pars nervosa and co-localises with somatolactin. In the pituitary gland, pthrp, pth1r and casr mRNAs were downregulated after both short- and long-term exposure to DSW. A correlation between pituitary gland pthrp mRNA expression and plasma Ca(2+) (R(2)=0.71, N=7, P<0.01) was observed. In gill tissue, pthrp and pth1r mRNAs were significantly upregulated after 30 days exposure to DSW, whereas no effect was found for casr mRNA expression. We conclude that in water of low salinity, declining pituitary gland pthrp mRNA expression accompanied by constant plasma sPTHrP levels points to a reduced sPTHrP turnover and that sPTHrP, through paracrine interaction, is involved in the regulation of branchial calcium handling, independently of endocrine pituitary gland sPTHrP.

P> The influences of dietary phosphorus (P) and food concentration on the calcium (Ca) balance in Daphnia magna were examined in this study at two different ambient Ca concentrations (0.5 and 10 mg Ca L-1). Daphnia were grown by feeding the young adults differentially under contrasting dietary P conditions [molar C : P ratio = c. 900 and c. 90 as low P (LP) and high P (HP), respectively], ambient Ca concentrations [0.5 mg and 10 mg Ca L-1 as low Ca (LCa) or high Ca (HCa), respectively] and food levels [0.15 or 1.5 mg C L-1 as low food (LF) or high food (HF), respectively] for 5 days. The specific Ca contents of daphniids (1.9-6.5\% of dry weight-1) increased with increasing Ca concentration, food level and dietary P content, although the food level did not affect the Ca content in the HPHCa treatment. A radioactive tracer method showed that the food level did not affect the influx of Ca from the water under LP conditions, but the Ca influx under HP conditions doubled with a HF level. A LP condition also led to a decrease in Ca influx with a HF level. During the 3 days of efflux, generally only a small proportion of Ca (2.6-3.3\%) was retained by the daphniids, but this retention increased (14-23\%) under low ambient Ca concentrations and under P-limitation. Excretion was the most important pathway for Ca loss (accounting for 50-60\% of body Ca), followed by moulting (20-47\%), but the relative contribution of these two pathways (excretion and moulting) did not vary among all the different treatments. The absolute loss of Ca through excretion and moulting, on the contrary, differed with different ambient Ca concentrations and dietary P conditions. A HF level led to an increase in the loss rates in most cases. Our study strongly suggested that there is an interaction between an essential metal (Ca) and macronutrients (C and P) in freshwater crustaceans with HCa and P contents. The results imply that variation in environmental nutrient conditions may change the Ca budg

Experiments to evaluate the effect of in-season calcium (Ca) sprays on late-season peach (Prunus persica L. Batsch cv. Calrico) were carried out for a 2-year period. Calcium formulations (0.5% and 1.0% in 2008 and only 0.5% tested in 2009) supplied either as CaCl2 or Ca propionate in combination with two or three adjuvants (0.05% of the nonionic surfactants Tween 20 and Break Thru, and 0.5% carboxymethylcellulose, CMC) were sprayed four to five times over the growing season. Peach mesocarp and endocarp Ca concentrations were determined on a 15-day basis from the beginning of May until the end of June. Further tissue analyses were performed at harvest. A decreasing trend in fruit Ca concentrations over the growing season was always observed regardless of the Ca treatments. Both in 2008 and 2009, significant tissue Ca increments associated with the application of Ca-containing sprays in combination with adjuvants were only observed in June, which may be coincident with the period of pit hardening. In 2008, both at harvest and after cold storage, the total soluble-solids concentration (° Brix) of fruits supplied with Ca propionate (0.5% and 1.0% Ca) was always lower as compared to the rest of treatments. The application of multiple Ca-containing sprays increased firmness at harvest and after cold storage, especially when CaCl2 was the active ingredient used. Supplying the adjuvants Tween 20 and CMC increased fruit acidity both at harvest and after cold storage. Evaluation of the development of physiological disorders after cold storage (2 weeks at 0°C) indicated a lower susceptibility of Ca-treated fruits to internal browning. Fruits treated with multiple CaCl2-, CMC-, and Break Thru®-containing sprays during the growing season were significantly less prone to the development of chilling injuries as compared to untreated peaches.

Experiments to evaluate the effect of in-season calcium (Ca) sprays on late-season peach (Prunus persica L. Batsch cv. Calrico) were carried out for a 2-year period. Calcium formulations (0.5% and 1.0% in 2008 and only 0.5% tested in 2009) supplied either as CaCl2 or Ca propionate in combination with two or three adjuvants (0.05% of the nonionic surfactants Tween 20 and Break Thru, and 0.5% carboxymethylcellulose, CMC) were sprayed four to five times over the growing season. Peach mesocarp and endocarp Ca concentrations were determined on a 15-day basis from the beginning of May until the end of June. Further tissue analyses were performed at harvest. A decreasing trend in fruit Ca concentrations over the growing season was always observed regardless of the Ca treatments. Both in 2008 and 2009, significant tissue Ca increments associated with the application of Ca-containing sprays in combination with adjuvants were only observed in June, which may be coincident with the period of pit hardening. In 2008, both at harvest and after cold storage, the total soluble-solids concentration (° Brix) of fruits supplied with Ca propionate (0.5% and 1.0% Ca) was always lower as compared to the rest of treatments. The application of multiple Ca-containing sprays increased firmness at harvest and after cold storage, especially when CaCl2 was the active ingredient used. Supplying the adjuvants Tween 20 and CMC increased fruit acidity both at harvest and after cold storage. Evaluation of the development of physiological disorders after cold storage (2 weeks at 0°C) indicated a lower susceptibility of Ca-treated fruits to internal browning. Fruits treated with multiple CaCl2-, CMC-, and Break Thru®-containing sprays during the growing season were significantly less prone to the development of chilling injuries as compared to untreated peaches.

Two metabolism experiments were carried out, to determine the effect of microbial phytase addition to barley-canola meal and barley-soybean meal diets on P and Ca balance in growing. pigs; In experiment 1, six barrows (29.6kg: initial LW) were fed a barley-canola meal diet, without or. with phytase (500 units.kg(-1) ring 24 days, according to a crossover design. The diet provided suboptimal levels. of P. In experiment 2, twelve barrows (53.4kg initial LW) were fed four barley-soybean meal diets, according to a two-period changeover design; Diet 1 was supplemented with inorganic P and Ca to meet requirements,. diets, 2, 3 and 4 contained suboptimal levels of P, diet 3 being supplemented with phytase; diet 4 was supplemented with both phytase and a mixture of xylanase and beta-glucanase. The supplementation of phytase to the barley-canola meal and the barley-soybean meal diets increased (P0.05) values far P retention and P and Ca digestibilities as for diets 1 and 3. In conclusion; phytase supplementation to the barley-canola meal and barley-soybean meal diets improved the utilization of P and digestibility of Ca; but no further effect was observed with the supplementation with the mixture of xylanase and beta-glucanase.

Contains fulltext : 19183_calcbaint.pdf (publisher's version ) (Open Access)

In all teleost fishes vitellogenesis is triggered and maintained by oestradiol-17beta (E2) and is accompanied by an increase of blood plasma calcium and phosphate. The action of this hormone on calcium metabolism was investigated by treating fast-growing immature juvenile sea bream (Sparus aurata) with coconut butter implants alone (control) or implants containing 10 microg/g E2. Treatment with E2 induced the production of circulating vitellogenin, a 2.5-fold increase in plasma ionic Ca2+ and a 10-fold increase in plasma total calcium, largely bound to protein. In contrast to freshwater species, which obtain most of their calcium from the environment directly through the gills, the intestinal component of calcium uptake of the salt water-living sea bream represented up to 60-70% of the total uptake. The whole body calcium uptake, expressed as the sum of calcium obtained via intestinal and extra-intestinal (likely branchial) routes increased significantly in response to E2. Combined influx and unchanged efflux rates resulted in a significant 31% increase in net calcium uptake. There was no evidence for an effect of E2 on the calcium and phosphate content of the scales or the tartrate-resistant acid phosphatase activity (an index for bone/scale osteoclast activity). While most freshwater fish appear to rely on internal stores of calcium, i.e. bone and/or scales to increase calcium availability, the marine sea bream accommodates calcium-transporting mechanisms to obtain calcium from the environment and preserve internal stores. These observations suggest that a fundamental difference may exist in the E2-dependent calcium regulation between freshwater and marine teleosts.

Contains fulltext : 14214.pdf (publisher's version ) (Closed access)

Department of Human Biology, University of Limburg, Maastricht, The Netherlands. The present study was conducted to investigate the effect of dietary protein on urinary Ca excretion, apparent Ca absorption and Ca balance in young and elderly subjects. Young adults (n 29) and elderly persons (n 26) consumed diets containing 12% (diet A) and 21% (diet B) of total energy as protein for 3 weeks according to a randomized crossover design. Results showed no differences between the two age groups with respect to the interaction between protein intake and Ca excretion (both in urine and in faeces), apparent Ca absorption and Ca balance. Therefore analyses were done for both age groups separately and also for the whole group. In elderly persons and in the whole group the Ca excretion in faeces (as a percentage of Ca intake) was lower during the higher protein intake (elderly: diet A, 106 (SEM 7)%; diet B, 86 (SEM 7)%; P = 0.018; whole group: diet A, 99 (SEM 4)%; diet B, 84 (SEM 4)%; P = 0.003). In young adults faecal Ca excretion tended to be lower when they consumed diet B (diet A: 94 (SEM 5)%; diet B: 83 (SEM 6)%; P = 0.093). Relative urinary Ca excretion was greater during the higher protein intake in young adults and in the whole group while relative urinary Ca excretion was not different in the elderly (diet A: 15 (SEM 1)%, 14 (SEM 1)%, 15 (SEM 1)%; diet B: 16 (SEM 1)%, 16 (SEM 1)%, 17 (SEM 2)% for the whole group, the young and elderly subjects respectively, P = 0.019; P = 0.016; P = 0.243). The resulting Ca balance was not influenced by the amount of protein in the diet in young adults. Values for the elderly and for the whole group showed that the Ca balance during diet A was significantly more negative compared with Ca balance during diet B, despite the higher urinary Ca excretion during diet B. It can be concluded that increasing the protein intake from 12 to 21% of total energy intake had no negative effect on Ca balance. Publication Types

These data suggest that calcium may be lost during heavy sweating conditions (up to 20 mg calcium/hour) and that this loss should be considered in establishing recommended allowances for calcium. It was observed that 7 men consuming 441 mg of calcium a day in a study extending for 48 days, excreted 8.1, 11.6 and 20.2 mg/hour of calcium when living at 70, 85 and 100°F. This accounted for 21.8, 25.1 and 33.2% of the total calcium excreted. These observations are important since they show an additional calcium loss, which has not been reported in previous calcium balance studies in the literature. It is questionable whether an individual, consuming a low calcium diet, ever really attains calcium balance (equilibrium), under heavy sweating conditions. It was observed that (a) the calcium excreted in sweat, in men working at a moderate rate in extreme heat (100°F), was still fairly high after acclimatization, averaging 17 mg/hour after the first 4 days, and (b) that the daily total calcium in sweat increased as the sweat rate increased. Therefore it appears that the calcium requirements may be increased under these conditions. It was shown that even after acclimatization the urinary calcium did not decrease in compensation for the losses of calcium in sweat. It is recognized that changes in the urinary excretion of calcium in adjusting to different levels of dietary calcium and the various other metabolic factors, may require months to achieve.

Promotores : S. Wendelaar Bonga en A. van Overbeeke, Contains fulltext : mmubn000001_028063929.pdf (publisher's version ) (Open Access)

Mineral and bone disorders (MBD) are common in patients with chronic kidney disease (CKD), contributing to significant morbidity and mortality. For several decades, the first-line approach to controlling hyperparathyroidism in CKD was by exogenous calcium loading. Since the turn of the millennium, however, a growing awareness of vascular calcification risk has led to a paradigm shift in management and a move away from calcium-based phosphate binders. As a consequence, contemporary CKD patients may be at risk of a negative calcium balance, which, in turn, may compromise bone health, contributing to renal bone disease and increased fracture risk. A calcium intake below a certain threshold may be as problematic as a high intake, worsening the MBD syndrome of CKD, but is not addressed in current clinical practice guidelines. The CKD-MBD and European Renal Nutrition working groups of the European Renal Association (ERA), together with the CKD-MBD and Dialysis working groups of the European Society for Pediatric Nephrology (ESPN), developed key evidence points and clinical practice points on calcium management in children and adults with CKD across stages of disease. These were reviewed by a Delphi panel consisting of ERA and ESPN working groups members. The main clinical practice points include a suggested total calcium intake from diet and medications of 800–1000 mg/day and not exceeding 1500 mg/day to maintain a neutral calcium balance in adults with CKD. In children with CKD, total calcium intake should be kept within the age-appropriate normal range. These statements provide information and may assist in decision-making, but in the absence of high-level evidence must be carefully considered and adapted to individual patient needs., Mineral and bone disorders (MBD) are common in patients with chronic kidney disease (CKD), contributing to significant morbidity and mortality. For several decades, the first-line approach to controlling hyperparathyroidism in CKD was by exogenous calcium loading. Since the turn of the millennium, however, a growing awareness of vascular calcification risk has led to a paradigm shift in management and a move away from calcium-based phosphate binders. As a consequence, contemporary CKD patients may be at risk of a negative calcium balance, which, in turn, may compromise bone health, contributing to renal bone disease and increased fracture risk. A calcium intake below a certain threshold may be as problematic as a high intake, worsening the MBD syndrome of CKD, but is not addressed in current clinical practice guidelines. The CKD-MBD and European Renal Nutrition working groups of the European Renal Association (ERA), together with the CKD-MBD and Dialysis working groups of the European Society for Pediatric Nephrology (ESPN), developed key evidence points and clinical practice points on calcium management in children and adults with CKD across stages of disease. These were reviewed by a Delphi panel consisting of ERA and ESPN working groups members. The main clinical practice points include a suggested total calcium intake from diet and medications of 800-1000 mg/day and not exceeding 1500 mg/day to maintain a neutral calcium balance in adults with CKD. In children with CKD, total calcium intake should be kept within the ; on behalf of European Renal Osteodystrophy (EUROD), an initiative of the Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) and the European Renal Nutrition (ERN) Working Groups of the European Renal Association (ERA) and the European Society of Pediatric Nephrology (ESPN) age-appropriate normal range. These statements provide information and may assist in decision-making, but in the absence of high-level evidence must be carefully consi

The thesis explores various facets of canine hypercortisolism (HC), commonly known as Cushing's syndrome, which affects 1-2 cases per 1000 dogs annually. Initially, it provides a comprehensive overview covering clinical manifestations, diagnostic methods, and treatment options for HC. A particular focus is given to severe muscle stiffness (SMS), a poorly understood clinical sign associated with HC, with an in-depth analysis of a cohort experiencing both HC and SMS, revealing it as a rare condition affecting only dogs with pituitary-dependent hypercortisolism (PDH)without impacting life expectancy. Furthermore, the thesis investigates the relationship between HC and calcium homeostasis, uncovering elevated phosphate levels and parathyroid hormone concentrations in dogs with HC, affirming cortisol's impact on calcium balance. Diagnostic challenges in HC are highlighted due to the lack of a gold standard test, often resulting in false-positive or false-negative results. A survey among Western European primary care veterinarians reveals varying diagnostic approaches, raising concerns about potential overdiagnosis and lack of differentiation among cases, emphasizing the need for improved education in the field. Trilostane emerges as the preferred medical treatment for PDH, with ongoing debates regarding monitoring methods. While trilostane effectively manages most cases, a portion of dogs does not respond positively, with factors such as alopecia and ultrasound-detected adrenomegaly associated with poor response. The thesis also delves into alternative pituitary drug therapies targeting dopamine receptors, with cabergoline showing promise in inhibiting pituitary tumor growth when associated with trilostane. Overall, the thesis provides a multifaceted examination of HC in dogs, addressing clinical, diagnostic, therapeutic, and prognostic aspects while shedding light on the complexities and challenges involved in its management.

Calcium is a key ion involved in cardiac and skeletal muscle contractility, nerve function, and skeletal structure. Global calcium balance is affected by parathyroid hormone and vitamin D, and calcium is shuttled between the extracellular space and the bone matrix compartment dynamically. The kidney plays an important role in whole-body calcium balance. Abnormalities in the kidney transport proteins alter the renal excretion of calcium. Various hormonal and regulatory pathways have evolved that regulate the renal handling of calcium to maintain the serum calcium within defined limits despite dynamic changes in dietary calcium intake. Dysregulation of renal calcium transport can occur pharmacologically, hormonally, and via genetic mutations in key proteins in various nephron segments resulting in several disease processes. This review focuses on the regulation transport of calcium in the nephron. Genetic diseases affecting the renal handling of calcium that can potentially lead to changes in the serum calcium concentration are reviewed.

Military field exercises are characterised by high volumes of exercise and prolonged periods of load carriage. Exercise can decrease circulating serum calcium and increase parathyroid hormone and bone resorption. These disturbances to calcium and bone metabolism can be attenuated with calcium supplementation immediately before exercise. This randomised crossover trial will investigate the effect of calcium supplementation on calcium and bone metabolism, and bone mineral balance, during load carriage exercise in women. Methods Thirty women (eumenorrheic or using the combined oral contraceptive pill, intrauterine system, or intrauterine device) will complete two experimental testing sessions either with, or without, a calcium supplement (1000 mg). Each experimental testing session will involve one 120 min session of load carriage exercise carrying 20 kg. Venous blood samples will be taken and analysed for biochemical markers of bone resorption and formation, calcium metabolism, and endocrine function. Urine will be collected pre- and post-load carriage to measure calcium isotopes for the calculation of bone calcium balance. Discussion The results from this study will help identify whether supplementing women with calcium during load carriage is protective of bone and calcium homeostasis.

Calcium balance is of paramount importance for vertebrates. In fish, the endocrine modulators of calcium homeostasis include the stanniocalcin (STC), and some members of the parathyroid hormone (PTH) family, such as the PTH-related protein (PTHrP), acting as antagonists. STC is ubiquitously expressed in higher vertebrates. In turn, bony fish exhibit specific STC-producing glands named the corpuscles of Stannius (CS). Previous studies pointed to a calcium-sensing receptor (CaSR) involvement in the secretion of STC, but little is known of the involvement of other putative regulators. The CS provides a unique model to deepen the study of STC secretion. We developed an ex vivo assay to culture CS of fish and a competitive ELISA method to measure STC concentrations. As expected, STC released from the CS responds to CaSR stimulation by calcium, calcimimetics, and calcilytic drugs. Moreover, we uncover the presence (by PCR) of two PTHrP receptors in the CS, e.g., PTH1R and PTH3R. Thus, ex vivo incubations revealed a dose-response inhibition of STC secretion in response to PTHrP at basal Ca2+ concentrations. This inhibition is achieved through specific and reversible second messenger pathways (transmembrane adenylyl cyclases and phospholipase C), as the use of specific inhibitors highlights. Together, these results provide evidence for endocrine modulation between two antagonist hormones, STC and PTHrP., Foundation for Science and Technology (FST (Portugal), Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

Thearticle presents the results of the growing broiler goslings of the Kuban breedwhen the probiotics Vita fort and Lactobifadol are included in the feedingdiet. The periodic feeding probiotics for seven days/seven days’ break wasfound to provide, at the age of 62 days, an increase in body weight by 10.1%(pË‚0.01) when feeding Vita fort and by 3.7% when feeding Lactobifadol. Whileusing probiotics, protein metabolism increased in the body of broiler goslings,= and also in the digestibility of nutrients increased. Similarly, nitrogen,phosphorus, and calcium balance showed better performance in the goslings fedwith Vita fort. The use of probiotics enhanced protein metabolism and improvedthe process of splitting and assimilation of nutrients in the current study.

Cancer is the leading cause of death worldwide, accounting for nearly 10 million deaths in 2020. It leads cancer to being a global problem. Cancer can modify calcium signaling networks by altering the expression and function of cation channels, pumps, and transporter. One new molecular channel that promises to be targeted for cancer therapy is Transient Receptor Potential Channels (TRP). TRP contributes in the exchange and distribution of calcium both inside and outside the cell, especially Transient Receptor Potential Channels Vanilloid (TRPV) which is known to be associated with cancer. In this study, a literature review was conducted regarding the role of TRPV in cells and cancer taken from PubMed. Using SciWheel to manage literature, 37 selected literature used in this study are international literature that discusses the role of TRPV in cells and cancer. TRPV has 6 members, there are TRPV1-6 which are categorized into two groups, ThermoTRPV (TRPV1, TRPV2, TRPV3, and TRPV4) who sensitive to temperatures from dangerous to non-dangerous temperatures and Calcium Selective (TRPV5 and TRPV6) who sensitive to calcium and has the main role of large-scale body calcium homeostasis. In body cells, TRPV has an important role such as mechanosensor, sensitive to heat, skin and hair cell growth, sensitive to pain, and maintaining calcium balance in the body. In cancer, TRPV has a role in proliferation, invasion, migration, metastasis, and apoptosis. The important role that TRPV plays in body cells and cancer, can make TRPV a target of a drug to treat cancer through several mechanisms such as blocking the expression of TRPV in cancer cells which stimulates a decrease in cancer cell growth.

In addition to its function of innate immunity against invading pathogens, neutrophil extracellular traps (NETs) promote thrombosis, autoimmune disease, and cancer metastasis; therefore, unnecessary exposure to the triggers of infection-independent NET generation should be avoided. We herein show that inhibition of forward-mode Na⁺/Ca²⁺ exchange by amiloride analogs, 5-(N-ethyl-N-isopropyl)amiloride (EIPA) and 5-(N-Methyl-N-isobutyl)amiloride (MIA), triggers NETotic cell death independently of infectious stimuli. Isolated human neutrophils treated with EIPA and MIA undergo NETotic cell death by an increase of intracellular Ca²⁺ following activation of NADPH oxidase and the resultant upregulation of intracellular ROS. EIPA- and MIA-mediated intracellular Ca²⁺ increase is attributed to the competitive binding of EIPA and MIA against Na⁺ to Na⁺/Ca²⁺ exchanger 1 (NCX1). These results demonstrate a new mechanism of infection-independent NET generation and implicate NCX1 as a physiologic regulator of intracellular calcium balance and NETotic cell death.

AIMS: Atrial fibrillation (AF) is associated with higher mortality. Biomarkers may improve the understanding of key pathophysiologic processes in AF that lead to death. Using a new multiplex analytic technique, we explored the association between 268 biomarkers and cardiovascular (CV) death in anticoagulated patients with AF. METHODS AND RESULTS: A case-cohort design with 1.8 -1.9 years follow-up. The identification cohort included 517 cases and 4057 randomly selected patients from ARISTOTLE. The validation cohort included 277 cases and 1042 randomly selected controls from RE-LY. Plasma collected at randomization was analyzed with conventional immunoassays and the OLINK proximity extension assay-panels; CVDII, CVDIII, and Inflammation. Association between biomarkers and CV-death was evaluated using Random Survival Forest, Boruta and adjusted Cox-regression analyses.The biomarkers most strongly and consistently associated with CV-death were (hazard ratio for inter-quartile comparison [95% CI]): N-terminal pro-B-type natriuretic peptide (NT-proBNP; 1.63 [1.37-1.93]), cardiac troponin T (cTnT-hs; 1.60[1.35-1.88]), interleukin-6 (IL-6; 1.29[1.13-1.47]), growth differentiation factor-15 (GDF-15; 1.30[1.10-1.53]) fibroblast growth factor 23 (FGF-23; 1.21[1.10-1.33]), urokinase receptor (uPAR; 1.38[1.16-1.64]), trefoil factor 3 (TFF3; 1.27[1.10-1.46]), tumor necrosis factor receptor 1 (TNFR1; 1.21[1.01-1.45]), TNF-related apoptosis-inducing ligand receptor 2 (TRAILR2; 1.18[1.04-1.34]) and cathepsin L1 (CTSL1; 1.22[1.07-1.39]). CONCLUSION: In this comprehensive screening of 268 biomarkers in anticoagulated patients with AF the underlying mechanisms most strongly associated with CV-death were cardiorenal dysfunction (NT-proBNP, cTnT-hs, CTSL1, TFF3), oxidative stress (GDF-15), inflammation (IL-6, GDF-15), calcium balance, vascular and renal dysfunction (FGF-23), fibrinolysis (suPAR) and apoptosis (TNFR1, TRAILR2). These findings provide novel insights into pathophysiologic a

Nutrition is tightly associated with the risk of stone events. A part from genetic predisposition, a correct and balanced diet might prevent incident kidney stones. Several studies analyzed each dietary component and different diets to better understand their impact on stone recurrence. Fluids: High fluids intake is the most important factor for preventing kidney stones disease and for every 200 mL of water, the risk of stones is reduced by 13%. Soft drinks seems to be associated to a greater risk of stone events, whereas caffeine and citrus fruits juice are not. Calcium: Normally calcium intake with diet does not exceed 1.2 g/day. A balanced consumption of dairy products is capable of reducing oxalate intestinal absorption and urinary excretion compared to low calcium diet, being protective for stone disease. Oxalate: The exact amount of oxalate contained in different foods is difficult to estimate for its variability, even in the same aliment. In addition, the amount of oxalate consumed was shown to be only a minor risk factor for stone disease, whereas its intestinal absorption is strongly influenced by external factors, such as calcium intake. Dietary oxalate restriction is advisable only in patients with known elevated consumption. Sodium: High sodium intake is both associated with hypertension, heart disease and stone risk. Increased sodium consumption is directly associated to hypercalciuria in both calcium stone formers and healthy subjects. Although dietary sodium restriction to recommended values is always desirable in stone formers, it is difficult to achieve for its broad use in food preparation. Proteins: Animal proteins are associated to increased risk for stone formation, whereas vegetable and dairy proteins are not. Increased meat intake was associated to acidic urine pH, negative calcium balance and reduced anti-lithogenic urinary solutes excretion.Fruits and vegetables: Alkalizing foods are one of the most important factors

Mozzarella cheese stretching is a thermomechanical treatment influenced by factors such as pH, acidity, stretching time and temperature. The aim of this minireview is to provide information about the stretching step and the effect of the main factors on the functional properties of mozzarella. The presented studies show that stretching under higher temperatures promotes more interactions in the protein matrix, and changes occur in the calcium balance throughout the storage period that influence water mobility, proteolysis and lead to changes in mozzarella properties. Therefore, the information presented in this minireview may facilitate the production of mozzarella cheese with specific functional properties., Rastezanje sira mozzarella je termomehanički postupak na koji utječu različiti čimbenici, kao što su pH-vrijednost, kiselost, vrijeme rastezanja i temperatura. Svrha je ovog kratkog prikaza dati pregled informacija o postupku rastezanja i utjecaju najvažnijih čimbenika na funkcionalna svojstva sira mozzarella. Ispitivanja prikazana u ovom kratkom preglednom radu pokazuju da rastezanje pri visokim temperaturama potiče interakciju između proteina, pri čemu dolazi do promjene udjela kalcija tijekom skladištenja, što pak utječe na difuzivnost vode, proteolizu i svojstva sira mozzarella. Stoga podaci prikazani u ovom kratkom preglednom radu mogu pojednostaviti proizvodnju sira mozzarella s određenim funkcionalnim svojstvima.

Calcium supplements may induce hypercalcaemia in patients with chronic kidney disease (CKD) or patients on hemodialysis. Even in the absence of overt hypercalcaemia, calcium supplementation may be associated with a positive calcium balance and intracellular calcium overload. There is an increased risk of complex supraventricular, ventricular arrhythmias or the risk of suffering a cardiac arrest in the presence of hypercalcaemia and calcium overload in subjects with impaired or absent renal function. A maximum intake of 1000 mg elemental calcium, combining supplements and dietary calcium, together with a 1.5 mmol/l level in the dialysate, may be a safer (opinion based) recommendation in CKD patients. This is especially the case if the patient already shows signs of extra-skeletal calcification or if they present cardiac comorbidities. Lower calcium levels in the dialysis fluid might reduce the positive calcium balance but can increase intradialytic plasma calcium changes and therefore increase the risk of arrhythmias.

To maintain calcium homeostasis during physical inactivity, precise coordination is necessary between diferent organs of the body. There are a number of factors which alter an organism's calcium balance, such as growth, aging, physical inactivity and acquired or inherited disorders which ultimately lead to bone loss. In non-hibernating mammals, physical inactivity causes bone loss which may not be completely recoverable during the lifespan of an individual despite a resumption of activity. Extreme physical inactivity and nutritional deprivation are two other important factors that lead to bone loss in non-hibernating mammals. The mechanism of bone loss is still poorly understood, however, there is some evidence which shows that during hibernation, smaller mammals (ground squirrels, bats, and hamsters) undergo bone loss. While on the other hand, hibernating bears do not show any sign of bone loss and retain their bone structure and strength. This may be due to diferences in their hibernation patterns, as smaller mammals may excrete calcium throughout the hibernation period, which ultimately leads to bone loss, whereas bears seem to have a more developed and advanced mechanism to prevent calcium loss and maintain their bone structure. In this review, we summarize calcium homeostasis and its adaptive mechanisms with reference to bone loss in hibernating as compared to non-hibernating mammals. We also review the efect of microgravity and simulated microgravity on bone physiology and subsequent adaptation.

Maillard reaction products (MRP) consumption has been related with the development of bone degenerative disorders, probably linked to changes in calcium metabolism. We aimed to investigate the effects of MRP intake from bread crust on calcium balance and its distribution, and bone metabolism. During 88 days, rats were fed control diet or diets containing bread crust as source of MRP, or its soluble high molecular weight, soluble low molecular weight or insoluble fractions (bread crust, HMW, LMW and insoluble diets, respectively). In the final week, a calcium balance was performed, then animals were sacrified and some organs removed to analyse calcium levels. A second balance was carried out throughout the experimental period to calculate global calcium retention. Biochemical parameters and bone metabolism markers were measured in serum or urine. Global calcium bioavailability was unmodified by consumption of bread crust or its isolate fractions, corroborating the previously described low affinity of MRP to bind calcium. Despite this, a higher calcium concentration was found in femur due to smaller bones having a lower relative density. The isolate consumption of the fractions altered some bone markers, reflecting a situation of increased bone resorption or higher turnover; this did not take place in the animals fed the bread crust diet. Thus, the bread crust intake does not affect negatively calcium bioavailability and bone metabolism.

With a summary in Dutch. - Dissertation Radboud University of Nijmegen, Contains fulltext : 65553_renahy.pdf (publisher's version ) (Open Access), Calcium is very important for many physiological functions that take place in the body. The interaction between intestines, kidneys, and bone is essential to maintain a normal calcium balance. The process of active calcium in the intestines and kidneys is very important to determine the amount of calcium resent in the body, which is regulated by calciotropic hormones like vitamin D and parathyroid hormone. In the kidney, calcium is reabsorbed from the pro-urine to the blood in a passive (paracellular, 85%) as well as an active (transcellular, 15%) manner. Furthermore, a small amount of calcium is excreted via the urine. The calcium channel TRPV5 is a key player in the process of active calcium reabsorption in the kidney. A mouse hypercalciuric mouse model was investigated intensively and the research described in this thesis shows new insights into the mechanisms that are involved in calcium homeostasis. This knowledge facilitates the development of new treatments for people with a disturbed calcium balance.

The role of dietary protein in weight loss and weight maintenance encompasses influences on crucial targets for body weight regulation, namely satiety, thermogenesis, energy efficiency, and body composition. Protein-induced satiety may be mainly due to oxidation of amino acids fed in excess, especially in diets with "incomplete" proteins. Protein-induced energy expenditure may be due to protein and urea synthesis and to gluconeogenesis; "complete" proteins having all essential amino acids show larger increases in energy expenditure than do lower-quality proteins. With respect to adverse effects, no protein-induced effects are observed on net bone balance or on calcium balance in young adults and elderly persons. Dietary protein even increases bone mineral mass and reduces incidence of osteoporotic fracture. During weight loss, nitrogen intake positively affects calcium balance and consequent preservation of bone mineral content. Sulphur-containing amino acids cause a blood pressure-raising effect by loss of nephron mass. Subjects with obesity, metabolic syndrome, and type 2 diabetes are particularly susceptible groups. This review provides an overview of how sustaining absolute protein intake affects metabolic targets for weight loss and weight maintenance during negative energy balance, i.e., sustaining satiety and energy expenditure and sparing fat-free mass, resulting in energy inefficiency. However, the long-term relationship between net protein synthesis and sparing fat free mass remains to be elucidated. Expected final online publication date for the Annual Review of Nutrition Volume 29 is July 17, 2009. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.

Perchlorate occurs in ground and surface waters in 44 states in the USA, primarily as a result of AP discharge from rocket fuel manufacturing facilities or from the demilitarization of missiles (Urbansky, 1998). AP is highly water-soluble and, as a result of the very slow reduction of the central chlorine atom, can persist in the environment for decades (Urbansky, 1998). Perchlorate is known to prevent intake of iodine from water or food and thus it is goitrogenic (thyroid gland inhibitor) in many animals including fishes and amphibians (Miranda et al., 1996; Manzon and Youson, 1997). Ionic perchlorate also alters calcium balance in fishes and amphibians (Luttgau et al., 1983; Thevenod et al., 1992; Jong et al., 1997) as well as other vertebrates. Calcium is a ubiquitous chemical messenger that is involved in the regulation of cellular function. Endocrine glands require calcium for the normal secretion of hormones and therefore contaminant-induced disruption of calcium balance can lead to systemic endocrine disruption. Because of the important role played by hormones in animal development and reproduction, endocrine disruption is likely to lead to serious impairments in growth, reproductive fitness, and consequently, amphibian and wildlife population stability as well as human health. We have previously examined aspects of growth and development and thyroid function in anuran larvae collected from AP-contaminated sites at the Longhorn Army Ammunition Plant (LHAAP) located in Karnack, Texas, and identified two possible cases of thyroid disruption. Bullfrog larvae collected from an AP-contaminated pond exhibited decreased hindlimb growth than larvae from a reference pond, even though the animals from both sites were of identical body length, and presumably, identical age class., The original document contains color images.

Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve postmenopausal women drank 100 ml of water containing 5 or 10 g of lactulose or a reference substance at breakfast for 9 days. The three treatments were given according to a randomized, double-blind, cross-over design, separated by two 19-day wash-out periods. On the 8th day of each treatment period, 44Ca dissolved in orange juice was drunk immediately after the solution with the study substance and just before a standard breakfast with 162 mg of carrier calcium. Within half an hour, 48Ca was given intravenously. Based on isotope ratios measured in urine collected before and until 36 h after isotope administration, true fractional calcium absorption was calculated. Calcium absorption during the treatments with the reference substance, 5 g and 10 g of lactulose was (mean ± SD) 27.7 ± 7.7, 30.0 ± 7.6, and 32.2 ± 7.0, respectively. A significant difference in calcium absorption was found between the highest dose of lactulose and the reference treatment (p < 0.01). A significant linear trend was found between the dose of lactulose and its positive effect on calcium absorption. In conclusion, in postmenopausal women a 9-day consumption of lactulose increases calcium absorption in a dose- response way. More research is warranted to explore how lactulose stimulates calcium absorption and whether it is able to improve calcium balance and/or to attenuate the rate of aging bone loss.

Chokchai Chotboon,1 Sukree Soontrapa,1 Pranom Buppasiri,1 Benja Muktabhant,2 Kiattisak Kongwattanakul,1 Jadsada Thinkhamrop1 1Department of Obstetrics and Gynecology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; 2Faculty of Public Health, Research Group on Prevention and Control of Diabetes in the Northeast, Khon Kaen University, Khon Kaen, Thailand Background: Calcium is an essential element for the body, which is taken through the dietary sources. Calcium supplements may be needed to achieve the dietary reference intake (DRI). Dietary calcium and supplemental calcium intake for calcium balance might be necessary. However, increasing evidence shows that calcium supplementation may enhance soft tissue calcification and cause cardiovascular diseases. Calcium requirement during pregnancy is markedly increased. If calcium supplementation depends on the dietary style of a region, then the adequacy of dietary calcium intake may guide the calcium supplementation. Materials and methods: A cross-sectional descriptive study was conducted among pregnant women who attended prenatal care at Srinagarind Hospital, Khon Kaen University. We used semiquantitative food frequency questionnaire (SFFQ) to evaluate the amount of daily calcium intake, and 3 days food record to assess the SFFQ reliability. We used the INMUCAL-N V.3.0, based on the Thai food composition table for nutritional calculation. Results: Among 255 recruited pregnant women, the mean daily dietary calcium intake was 1,256.9 mg/day (SD: 625.1) and up to 1,413.4 mg/day (SD: 601.3) in daily milk consumed group. Based on Thai DRI for pregnant women, with 800 mg/day as adequate intake of calcium, 74.9% had adequate calcium intake, and majority of them had milk daily. Conclusion: The majority of pregnant women in a province of Northeast Thailand had adequate calcium intake, particularly those who had milk with their meal every day. Keywords: calcium intake, pregnant women

Contains fulltext : 173075.pdf (publisher's version ) (Closed access), Maintaining plasma calcium levels within a narrow range is of vital importance for many physiological functions. Therefore, calcium transport processes in the intestine, bone and kidney are tightly regulated to fine-tune the rate of absorption, storage and excretion. The TRPV5 and TRPV6 calcium channels are viewed as the gatekeepers of epithelial calcium transport. Several calciotropic hormones control the channels at the level of transcription, membrane expression, and function. Recent technological advances have provided the first near-atomic resolution structural models of several TRPV channels, allowing insight into their architecture. While this field is still in its infancy, it has increased our understanding of molecular channel regulation and holds great promise for future structure-function studies of these ion channels. This review will summarize the mechanisms that control the systemic calcium balance, as well as extrapolate structural views to the molecular functioning of TRPV5/6 channels in epithelial calcium transport.

Introduction: Vitamin D insufficiency, even in its milder form, is associated with an increased risk of fracture through negative calcium balance. Clinical studies have indicated that intervention with vitamin D supplementation reduced the incidence of falling in elderly subjects. Vitamin D insufficiency is common worldwide irrespective of latitude of countries. Objective: In current study we intended to find prevalence and severity of vitamin D deficiency in patients, who presented with various type of fractures sustained following trivial trauma. Results: One hundred and four patients who suffered low velocity trauma, presented with various fractures were studied. Fractures around the hip were commonest (39.42 %), followed by Colles (24.03%) and vertebral fractures (17.30 %).Serum vitamin D levels of the patients showed 65.38% were having deficient levels, whereas 18.26 % were having insufficient levels. Conclusion: Our study indicates very high incidence of vitamin D deficiency among patients who suffered fractures following trivial trauma. The high incidence of fractures in elderly population with vitamin D deficiency probably is partly because of altered bone mass and strength, and partly because of poor muscular control because of pain and muscle weakness.

Osteoporosis didefenisikan sebagai pengurangan masa dan kekuatan tulang sehingga meningkatakan risiko fraktur. Di Amerika serikat, terjadi pada 1 dari 2 wanita usia lebih dari 50 tahun dan meningkat sejalan dengan bertambahnya usia, mengakibatkan fraktur, meningkatkan morbiditas serta mortalitas.Hipertiroidisme mencetuskan bone turnover dan mempersingkat siklus remodelling tulang normal dan lebih sering merusak tulang kortikal (hip dan forearm) dibanding tulang trabekular (spine).Hypertiroidisme berkaitan dengan remodelling tulang, menurunnya densitas tulang, osteoporosis dan meningkatnya kejadian fraktur. Konsentrasi hormon tiroid yang tinggi dalam jangka waktu lama meningkatkan risiko osteoporosis dan risiko fraktur. Perubahan metabolisme tulang berkaitan dengan keseimbangan kalsium negatif, hiperkalsiuria dan kadang-kadang hiperkalsemia. Penanganan terhadap hipertiroidisme akan mengembalikan densitas tulang.Abstract. Osteoporosis is defined as low bone mass density that increase fractur risk. In US, 0steoporosis affecting approximately 1 of 2 old women and increase fractur risk, morbidity and mortality.Hipertiroidisme causes bone turnover and stimullates bone remodelling cycle, cortikal (hip and forearm) than trabecular (spine).Hypertiroidisme was associated with bone remodelling, reduced bone density, osteoporosis and could increase fracture risk. High concentration of thyroid hormone causes osteoporosis and increase fracture risk. Changes in bone metabolism are associated with negative calcium balance, hypercalciuria and, rarely, hypercalcemia Management of hypertiroidisme affects bone density.

Tenofovir disoproxil fumarate (TDF) causes bone, endocrine, and renal changes by an unknown mechanism(s). Data are limited on tenofovir pharmacokinetics and these effects. Using baseline data from a multicenter study of HIV-infected youth on stable treatment with regimens containing TDF (n = 118) or lacking TDF (n = 85), we measured cross-sectional associations of TDF use with markers of renal function, vitamin D-calcium-parathyroid hormone balance, phosphate metabolism (tubular reabsorption of phosphate and fibroblast growth factor 23 [FGF23]), and bone turnover. Pharmacokinetic-pharmacodynamic associations with plasma tenofovir and intracellular tenofovir diphosphate concentrations were explored among those receiving TDF. The mean age was 20.9 (standard deviation [SD], 2.0) years; 63% were male; and 52% were African American. Compared to the no-TDF group, the TDF group showed lower mean estimated glomerular filtration rates and tubular reabsorption of phosphate, as well as higher parathyroid hormone and 1,25-dihydroxy vitamin D [1,25-OH(2)D] levels. The highest quintile of plasma tenofovir concentrations was associated with higher vitamin D binding protein, lower free 1,25-OH(2)D, higher 25-OH vitamin D, and higher serum calcium. The highest quintile of intracellular tenofovir diphosphate concentration was associated with lower FGF23. Higher plasma tenofovir concentrations were associated with higher vitamin D binding protein and lower free 1,25-OH(2)D, suggesting a functional vitamin D deficiency explaining TDF-associated increased parathyroid hormone. The finding of lower FGF23 accompanying higher intracellular tenofovir diphosphate suggests that different mechanisms mediate TDF-associated changes in phosphate handling. Separate pharmacokinetic properties may be associated with distinct TDF toxicities: tenofovir with parathyroid hormone and altered calcium balance and tenofovir diphosphate with hypophosphatemia and FGF23 regulation. (The clinical trial registrat

Item does not contain fulltext, The cecum, the proximal part of the large intestine, has the highest rate of calcium absorption compared with other intestinal segments. Previously, we showed that rats with the cecum surgically removed (cecectomized rats) had severe negative calcium balance, low bone mineral density (BMD), and a compensatory increase in colonic calcium absorption. Herein, we used the computer-assisted bone histomorphometric technique and microcomputed tomography (muCT) to analyze bone microstructural defects in cecectomized rats at 1 and 3 mo postsurgery compared with age-matched sham-operated control rats. Relatively low BMD as determined by dual energy X-ray absorptiometry was observed in the femora, tibiae, and lumbar vertebrae of the 3-mo cecectomized rats. muCT analysis revealed decreases in the tibial cortical thickness, periosteal and endosteal perimeters, and moment of inertia in cecectomized rats. The histomorphometric results further showed that trabecular bone volume and number were markedly decreased, whereas trabecular separation was increased in the proximal tibial metaphysis of cecectomized rats, thus leading to a decrease in trabecular volumetric BMD. Since osteoclast surface and eroded surface were increased after cecectomy, such bone loss in cecectomized rats appeared to result from an enhanced bone resorption. Moreover, decreases in bone formation rate and osteoblast surface indicated a suppression of osteoblast-mediated bone formation. In conclusion, cecectomy induced widespread osteopenia in rats presumably by enhancing the osteoclast-mediated bone resorption and suppressing bone formation. The present results underline the important role of cecum in the body calcium homeostasis.

Item does not contain fulltext, An earlier study reported that cecal calcium absorption contributes less than 10% of total calcium absorbed by the intestine, although the cecum has the highest calcium transport rate compared with other intestinal segments. Thus, the physiological significance of the cecum pertaining to body calcium metabolism remains elusive. Herein, a 4-wk calcium balance study in cecectomized rats revealed an increase in fecal calcium loss with marked decreases in fractional calcium absorption and urinary calcium excretion only in the early days post-operation, suggesting the presence of a compensatory mechanism to minimize intestinal calcium wasting. Further investigation in cecectomized rats showed that active calcium transport was enhanced in the proximal colon but not in the small intestine, whereas passive calcium transport along the whole intestine was unaltered. Since apical exposure to calcium-sensing receptor (CaSR) agonists similarly increased proximal colonic calcium transport, activation of apical CaSR in colonic epithelial cells could have been involved in this hyperabsorption. Calcium transporter genes, i.e., TRPV6 and calbindin-D(9k), were also upregulated in proximal colonic epithelial cells. Surprisingly, elevated serum parathyroid hormone levels and hyperphosphatemia were evident in cecectomized rats despite normal plasma calcium levels, suggesting that colonic compensation alone might be insufficient to maintain normocalcemia. Thus, massive bone loss occurred in both cortical and trabecular sites, including lumbar vertebrae, femora, and tibiae. The presence of compensatory colonic calcium hyperabsorption with pervasive osteopenia in cecectomized rats therefore corroborates that the cecum is extremely crucial for body calcium homeostasis.

Item does not contain fulltext, BACKGROUND: Hypophosphatemia and bone disease are common in HIV-positive (HIV+) patients on tenofovir disoproxil fumarate-containing antiretroviral therapy (TDF-containing ART). The underlying etiology is not completely understood. OBJECTIVE: To examine the effects of treatment of calcium and vitamin D deficiency on phosphate metabolism and bone disease in HIV+ patients on tenofovir. METHODS: This was an open-label, pilot study of calcium and phosphate metabolism, bone turnover, and bone density in 24 HIV+ patients on TDF, who were receiving a 1-year treatment for vitamin D and/or calcium deficiency according to a predefined protocol. Eight patients without calcium or vitamin D deficiency served as controls. RESULTS: One-year treatment improved vitamin D levels, decreased serum parathyroid hormone (PTH), and improved calcium balance and bone mineral density. It did not affect the serum levels of PTH-related peptide (PTH-rp) or fibroblast growth factor 23 (FGF-23) nor did it raise serum phosphate levels or decrease renal phosphate loss. CONCLUSION: Treatment of calcium or vitamin D deficiency in HIV+ patients on ART including TDF has favorable effects on bone density, but it does not improve serum phosphate levels. Renal phosphate wasting in these patients is not caused by excess PTH, PTH-rp, or FGF-23 nor by vitamin D or calcium deficiency.

Gemma HornSurgical Department, Perth Royal Infirmary, Perth, ScotlandIntroduction: Osteoporosis is a common disease that affects both women and men but is more prevalent in postmenopausal women. Reviews suggest that dietary-derived calcium is vital in maintaining adequate calcium balance. Sources of dietary calcium intake among adult patients attending an osteoporosis clinic were reviewed.Method: Two hundred and ninety-one patients attending an osteoporosis clinic were given an eleven-item food questionnaire to complete. The results were compared to the recommended daily allowance of 700 mg.Results: The overall mean intake was 657 mg/day with little difference between age or gender. The best foods for supplying calcium were cheese and milky drinks.Conclusion: This study has confirmed that suboptimal calcium intakes remain common. Dairy sources of calcium remain important. More awareness is needed to convey the importance of dietary calcium and bone health to avoid the development of osteoporosis.Keywords: osteoporosis, clinic, food questionnaire, calcium, dietary intake, bone health

The overall objective of this project was to investigate the effects of consuming several different commercially available calcium supplements. Bioavailability, cost, convenience, physiological responses to each supplement, feasibility and need for a supplement by the targeted population were assessed. Three studies composed the project. The first study consisted of feeding a controlled diet to two groups of ten young adults. Subjects were fed a laboratory controlled diet with one of seven calcium supplements: milk, oyster shell calcium plus vitamin D, calcium lactate and gluconate, mixed calcium source (Mega-Cal), dolomite calcium, or purified calcium carbonate. Calcium carbonate supplementation resulted in the poorest calcium balances and longest fecal transit times while calcium gluconate required the consumption of the largest number of tablets at the highest cost to the consumer. Milk supplementation was fairly expensive, resulted in the highest calcium balance and lower fecal transit time and caused greatest complaints of gastro-intestinal distress. In Study II, seventy-two retired breeder female mice were fed a basal diet plus one of eight calcium supplements (seven described previously and an additional supplement-purified calcium carbonate plus vitamin D). Highest bone breaking strength was noted in the group of mice fed purified calcium carbonate plus vitamin D, but the calcium deficient group also had high bone breaking strength. The mice fed calcium gluconate had the best calcium absorption but mice fed purified calcium carbonate had the most positive calcium balance. In Study III, a survey was conducted to investigate relationship of calcium intake and urinary calcium excretion to other components of the self-selected diets of elderly persons. Only 36% of these elderly subjects consumed 75% or above of the RDA for calcium. Calcium intakes correlated significantly and positively with sodium intakes, phosphorus intakes and protein intakes and tended to co

This consensus article reviews the various aspects of the non-pharmacological management of osteoporosis, including the effects of nutriments, physical exercise, lifestyle, fall prevention, and hip protectors. Vertebroplasty is also briefly reviewed. Non-pharmacological management of osteoporosis is a broad concept. It must be viewed as an essential part of the prevention of fractures from childhood through adulthood and the old age. The topic also includes surgical procedures for the treatment of peripheral and vertebral fractures and the post-fracture rehabilitation. The present document is the result of a consensus, based on a systematic review and a critical appraisal of the literature. Diets deficient in calcium, proteins or vitamin D impair skeletal integrity. The effect of other nutriments is less clear, although an excessive consumption of sodium, caffeine, or fibres exerts negative effects on calcium balance. The deleterious effects of tobacco, excessive alcohol consumption and a low BMI are well accepted. Physical activity is of primary importance to reach optimal peak bone mass but, if numerous studies have shown the beneficial effects of various types of exercise on bone mass, fracture data as an endpoint are scanty. Fall prevention strategies are especially efficient in the community setting, but less evidence is available about their effectiveness in preventing fall-related injuries and fractures. The efficacy of hip protectors remains controversial. This is also true for vertebroplasty and kyphoplasty. Several randomized controlled studies had reported a short-term advantage of vertebroplasty over medical treatment for pain relief, but these findings have been questioned by recent sham-controlled randomized clinical studies.

This consensus article reviews the various aspects of the non-pharmacological management of osteoporosis, including the effects of nutriments, physical exercise, lifestyle, fall prevention, and hip protectors. Vertebroplasty is also briefly reviewed. Non-pharmacological management of osteoporosis is a broad concept. It must be viewed as an essential part of the prevention of fractures from childhood through adulthood and the old age. The topic also includes surgical procedures for the treatment of peripheral and vertebral fractures and the post-fracture rehabilitation. The present document is the result of a consensus, based on a systematic review and a critical appraisal of the literature. Diets deficient in calcium, proteins or vitamin D impair skeletal integrity. The effect of other nutriments is less clear, although an excessive consumption of sodium, caffeine, or fibres exerts negative effects on calcium balance. The deleterious effects of tobacco, excessive alcohol consumption and a low BMI are well accepted. Physical activity is of primary importance to reach optimal peak bone mass but, if numerous studies have shown the beneficial effects of various types of exercise on bone mass, fracture data as an endpoint are scanty. Fall prevention strategies are especially efficient in the community setting, but less evidence is available about their effectiveness in preventing fall-related injuries and fractures. The efficacy of hip protectors remains controversial. This is also true for vertebroplasty and kyphoplasty. Several randomized controlled studies had reported a short-term advantage of vertebroplasty over medical treatment for pain relief, but these findings have been questioned by recent sham-controlled randomized clinical studies., Journal Article, Review, SCOPUS: ar.j, info:eu-repo/semantics/published