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John M Pettifor - One of the best experts on this subject based on the ideXlab platform.
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vitamin d treatment in Calcium Deficiency rickets a randomised controlled trial
Archives of Disease in Childhood, 2014Co-Authors: Tom D Thacher, Philip R Fischer, John M PettiforAbstract:Objective To determine whether children with CalciumDeficiency rickets have a better response to treatment with vitamin D and Calcium than with Calcium alone. Design Randomised controlled trial. Setting Jos University Teaching Hospital, Jos, Nigeria. Population Nigerian children with active rickets treated with Calcium carbonate as limestone (approximately 938 mg elemental Calcium twice daily) were, in addition, randomised to receive either oral vitamin D2 50 000 IU (Ca+D, n=44) or placebo (Ca, n=28) monthly for 24 weeks. Main outcome measure Achievement of a 10-point radiographic severity score ≤1.5 and serum alkaline phosphatase ≤350 U/L. Results The median (range) age of enrolled children was 46 (15–102) months, and baseline characteristics were similar in the two groups. Mean (±SD) 25-hydroxyvitamin D (25(OH)D) was 30.2±13.2 nmol/L at baseline, and 29 (43%) had values <30 nmol/L. Baseline alkaline phosphatase and radiographic scores were unrelated to vitamin D status. Of the 68 children (94% of original cohort) who completed 24 weeks of treatment, 29 (67%) in the Ca+D group and 11 (44%) in the Ca group achieved the primary outcome (p=0.06). Baseline 25(OH)D did not alter treatment group effects (p=0.99 for interaction). At the end of 24 weeks, 25(OH)D values were 55.4±17.0 nmol/L and 37.9±20.0 nmol/L in the Ca+D and Ca groups, respectively, (p<0.001). In the Ca+D and Ca groups, the final 25(OH)D concentration was greater in those who achieved the primary outcome (56.4±17.2 nmol/L) than in those who did not (37.7±18.5 nmol/L, p<0.001). Conclusions In children with Calcium-Deficiency rickets, there is a trend for vitamin D to improve the response to treatment with Calcium carbonate as limestone, independent of baseline 25(OH)D concentrations. Trial registration number ClinicalTrials.gov NCT00949832.
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vitamin d dietary Calcium Deficiency rickets and pseudo vitamin d Deficiency rickets
bonekey Reports, 2014Co-Authors: Francis H Glorieux, John M PettiforAbstract:This review describes the pathogenesis, clinical presentation and biochemical perturbations found in privational (nutritional) rickets and pseudo-vitamin D Deficiency rickets (PDDR), an autosomal recessive condition with loss of function mutations in CYP27B1. It may seem strange to combine a discussion on privational rickets and PDDR as a single topic, but privational rickets and PDDR present with similar clinical signs and symptoms and with similar perturbations in bone and mineral metabolism. Of interest is the characteristic lack of features of rickets at birth in infants with PDDR, a finding which has also been reported in infants born to vitamin D-deficient mothers. This highlights the independence of the fetus and neonate from the need for vitamin D to maintain Calcium homeostasis during this period. The variable roles of vitamin D Deficiency and dietary Calcium Deficiency in the pathogenesis of privational rickets are discussed and the associated alterations in vitamin D metabolism highlighted. Although PDDR is a rare autosomal recessive disorder, results of long-term follow-up are now available on the effect of treatment with calcitriol, and these are discussed. Areas of uncertainty, such as should affected mothers breastfeed their infants, are emphasized.
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metabolic bone disease in black teenagers with genu valgum or varum without radiologic rickets a bone histomorphometric study
Journal of Bone and Mineral Research, 2009Co-Authors: Christine M Schnitzler, John M Pettifor, Deepak N Patel, J M Mesquita, G P Moodley, D ZachenAbstract:Calcium Deficiency in black (African) children can cause rickets and osteomalacia with severe limb deformities. It is not known whether black teenagers with genu valgum or varum but without radiologic rickets suffer from a related disorder. To examine this question we studied 26 such patients by iliac crest bone biopsy and serum and urine biochemistry: 12 patients (46%) had osteopenia with normal or low bone turnover, 5 (19%) mildly increased bone turnover, 4 (15%) histologic hyperparathyroidism, 2 (8%) preosteomalacia, and 3 (12%) osteomalacia (with features of hyperparathyroidism). Radiographs did not reflect the severity of the bone disease. Serum Calcium levels correlated inversely with eroded mineralized surface (p < 0.001), osteoid surface (p < 0.01), osteoid thickness (p < 0.001), mineralization lag time (p < 0.001), and 1,25-(OH)2 vitamin D (p < 0.005), and 1,25-(OH)2 vitamin D correlated positively with osteoid surface (p < 0.05), osteoid thickness (p < 0.05), osteoid volume (p < 0.01), eroded surface (p < 0.05), and eroded mineralized surface (p < 0.0005). Tubular reabsorption of phosphate and 25-OH vitamin D levels were normal, and 1,25-(OH)2 vitamin D levels were normal to high. This suggests that Calcium Deficiency may have caused the increase in bone turnover and the mineralization defects. The most severe osteomalacia was found in males aged 16-19 years. We cannot explain the cause of the osteopenia. We conclude that all patients had bone disease.
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vitamin d or Calcium Deficiency rickets in infants children a global perspective
Indian Journal of Medical Research, 2008Co-Authors: John M PettiforAbstract:It was only in the early part of the 20th century with the discovery of vitamin D and of the role that ultraviolet light irradiation plays in vitamin D formation that rational and appropriate therapy became available and rickets was all but eradicated in a number of developed countries. Since then, there has been a resurgence of the disease in many countries such as in Europe and the USA probably due to an increase in the prevalence of breast feeding, the immigration of dark skinned families to countries of high latitude, and the avoidance of direct sunlight because of the risk of the development of skin cancers. The disease is also widely recognised in many developing countries, including some situated in subtropical regions. Studies have led to the realization that nutritional rickets may be caused by either vitamin D or Calcium Deficiency, but in the majority of situations variable combinations of both probably play a role. Although low dietary Calcium intakes appear to be central to the pathogenesis of rickets in Nigeria, genetic and/or other environmental factors are likely to contribute. But to date no single factor has been isolated as contributing significantly. The results of a recently conducted study suggest that in situation of low dietary Calcium intakes vitamin D requirements may be higher than normal, possibly predisposing those children with vitamin D levels in the low normal range to rickets. If this is so, it would indicate that the currently accepted normal range for vitamin D sufficiency would need to be adjusted depending on dietary Calcium intakes. Yet we are still unclear as to the factors which predispose some children to the disease.
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early response to vitamin d2 in children with Calcium Deficiency rickets
The Journal of Pediatrics, 2006Co-Authors: Tom D Thacher, Philip R Fischer, Christian O Isichei, John M PettiforAbstract:Objective To assess the effect of vitamin D 2 administration on serum vitamin D metabolite concentrations in Calcium Deficiency rickets. Study design We administered vitamin D 2 , 50,000 IU orally to 16 Nigerian children 15 to 48 months of age with radiographically active rickets. We measured Calcium and vitamin D metabolites at baseline and at 1, 3, 7, and 14 days. Results At baseline, ranges of serum 25-hydroxyvitamin D (25(OH)D) concentrations were 18 to 40 nmol/L (7-16 ng/mL), and 1,25-dihydroxyvitamin D (1,25-(OH) 2 D) concentrations were 290 to 790 pmol/L (120-330 pg/mL). After vitamin D administration, serum 25(OH)D and 1,25(OH) 2 D concentrations rapidly rose and peaked at 2.8 and 1.9 times the baseline values ( P 2 D and 25(OH)D were strongest at day 3 (r = 0.84, P P = .11). The relationship of 1,25(OH) 2 D with 25(OH)D at baseline and the increase in 1,25(OH) 2 D in response to vitamin D were similar to those described in children with vitamin D Deficiency. However, unlike the pattern in vitamin D Deficiency, 1,25(OH) 2 D remained positively correlated with 25(OH)D after administration of vitamin D. Conclusion Dietary Calcium Deficiency increases the demand for 25(OH)D above that required in vitamin D Deficiency to optimize 1,25(OH) 2 D concentrations. Assessment of vitamin D sufficiency in persons or communities may need to be adjusted for habitual dietary Calcium intake.
John P Legeros - One of the best experts on this subject based on the ideXlab platform.
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biphasic Calcium phosphate bioceramics preparation properties and applications
Journal of Materials Science: Materials in Medicine, 2003Co-Authors: Racquel Z Legeros, Ramin Rohanizadeh, Dindo Q Mijares, John P LegerosAbstract:Biphasic Calcium phosphate (BCP) bioceramics belong to a group of bone substitute biomaterials that consist of an intimate mixture of hydroxyapatite (HA), Ca10(PO4)6(OH)2, and beta-triCalcium phosphate (β-TCP), Ca3(PO4)2, of varying HA/β-TCP ratios. BCP is obtained when a synthetic or biologic Calcium-deficient apatite is sintered at temperatures at and above 700 °C. Calcium Deficiency depends on the method of preparation (precipitation, hydrolysis or mechanical mixture) including reaction pH and temperature. The HA/β-TCP ratio is determined by the Calcium Deficiency of the unsintered apatite (the higher the Deficiency, the lower the ratio) and the sintering temperature. Properties of BCP bioceramics relating to their medical applications include: macroporosity, microporosity, compressive strength, bioreactivity (associated with formation of carbonate hydroxyapatite on ceramic surfaces in vitro and in vivo), dissolution, and osteoconductivity. Due to the preferential dissolution of the β-TCP component, the bioreactivity is inversely proportional to the HA/β-TCP ratio. Hence, the bioreactivity of BCP bioceramics can be controled by manipulating the composition (HA/β-TCP ratio) and/or the crystallinity of the BCP. Currently, BCP bioceramics is recommended for use as an alternative or additive to autogeneous bone for orthopedic and dental applications. It is available in the form of particulates, blocks, customized designs for specific applications and as an injectible biomaterial in a polymer carrier. BCP ceramic can be used also as grit-blasting abrasive for grit-blasting to modify implant substrate surfaces. Exploratory studies demonstrate the potential uses of BCP ceramic as scaffold for tissue engineering, drug delivery system and carrier of growth factors.
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biphasic Calcium phosphate bioceramics preparation properties and applications
Journal of Materials Science: Materials in Medicine, 2003Co-Authors: Racquel Z Legeros, Ramin Rohanizadeh, Dindo Q Mijares, Shujie Lin, John P LegerosAbstract:Biphasic Calcium phosphate (BCP) bioceramics belong to a group of bone substitute biomaterials that consist of an intimate mixture of hydroxyapatite (HA), Ca(10)(PO(4))(6)(OH)(2), and beta-triCalcium phosphate (beta-TCP), Ca(3)(PO(4))(2), of varying HA/beta-TCP ratios. BCP is obtained when a synthetic or biologic Calcium-deficient apatite is sintered at temperatures at and above 700 degrees C. Calcium Deficiency depends on the method of preparation (precipitation, hydrolysis or mechanical mixture) including reaction pH and temperature. The HA/beta-TCP ratio is determined by the Calcium Deficiency of the unsintered apatite (the higher the Deficiency, the lower the ratio) and the sintering temperature. Properties of BCP bioceramics relating to their medical applications include: macroporosity, microporosity, compressive strength, bioreactivity (associated with formation of carbonate hydroxyapatite on ceramic surfaces in vitro and in vivo), dissolution, and osteoconductivity. Due to the preferential dissolution of the beta-TCP component, the bioreactivity is inversely proportional to the HA/beta-TCP ratio. Hence, the bioreactivity of BCP bioceramics can be controlled by manipulating the composition (HA/beta-TCP ratio) and/or the crystallinity of the BCP. Currently, BCP bioceramics is recommended for use as an alternative or additive to autogeneous bone for orthopedic and dental applications. It is available in the form of particulates, blocks, customized designs for specific applications and as an injectible biomaterial in a polymer carrier. BCP ceramic can be used also as grit-blasting abrasive for grit-blasting to modify implant substrate surfaces. Exploratory studies demonstrate the potential uses of BCP ceramic as scaffold for tissue engineering, drug delivery system and carrier of growth factors.
Racquel Z Legeros - One of the best experts on this subject based on the ideXlab platform.
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biphasic Calcium phosphate bioceramics preparation properties and applications
Journal of Materials Science: Materials in Medicine, 2003Co-Authors: Racquel Z Legeros, Ramin Rohanizadeh, Dindo Q Mijares, John P LegerosAbstract:Biphasic Calcium phosphate (BCP) bioceramics belong to a group of bone substitute biomaterials that consist of an intimate mixture of hydroxyapatite (HA), Ca10(PO4)6(OH)2, and beta-triCalcium phosphate (β-TCP), Ca3(PO4)2, of varying HA/β-TCP ratios. BCP is obtained when a synthetic or biologic Calcium-deficient apatite is sintered at temperatures at and above 700 °C. Calcium Deficiency depends on the method of preparation (precipitation, hydrolysis or mechanical mixture) including reaction pH and temperature. The HA/β-TCP ratio is determined by the Calcium Deficiency of the unsintered apatite (the higher the Deficiency, the lower the ratio) and the sintering temperature. Properties of BCP bioceramics relating to their medical applications include: macroporosity, microporosity, compressive strength, bioreactivity (associated with formation of carbonate hydroxyapatite on ceramic surfaces in vitro and in vivo), dissolution, and osteoconductivity. Due to the preferential dissolution of the β-TCP component, the bioreactivity is inversely proportional to the HA/β-TCP ratio. Hence, the bioreactivity of BCP bioceramics can be controled by manipulating the composition (HA/β-TCP ratio) and/or the crystallinity of the BCP. Currently, BCP bioceramics is recommended for use as an alternative or additive to autogeneous bone for orthopedic and dental applications. It is available in the form of particulates, blocks, customized designs for specific applications and as an injectible biomaterial in a polymer carrier. BCP ceramic can be used also as grit-blasting abrasive for grit-blasting to modify implant substrate surfaces. Exploratory studies demonstrate the potential uses of BCP ceramic as scaffold for tissue engineering, drug delivery system and carrier of growth factors.
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biphasic Calcium phosphate bioceramics preparation properties and applications
Journal of Materials Science: Materials in Medicine, 2003Co-Authors: Racquel Z Legeros, Ramin Rohanizadeh, Dindo Q Mijares, Shujie Lin, John P LegerosAbstract:Biphasic Calcium phosphate (BCP) bioceramics belong to a group of bone substitute biomaterials that consist of an intimate mixture of hydroxyapatite (HA), Ca(10)(PO(4))(6)(OH)(2), and beta-triCalcium phosphate (beta-TCP), Ca(3)(PO(4))(2), of varying HA/beta-TCP ratios. BCP is obtained when a synthetic or biologic Calcium-deficient apatite is sintered at temperatures at and above 700 degrees C. Calcium Deficiency depends on the method of preparation (precipitation, hydrolysis or mechanical mixture) including reaction pH and temperature. The HA/beta-TCP ratio is determined by the Calcium Deficiency of the unsintered apatite (the higher the Deficiency, the lower the ratio) and the sintering temperature. Properties of BCP bioceramics relating to their medical applications include: macroporosity, microporosity, compressive strength, bioreactivity (associated with formation of carbonate hydroxyapatite on ceramic surfaces in vitro and in vivo), dissolution, and osteoconductivity. Due to the preferential dissolution of the beta-TCP component, the bioreactivity is inversely proportional to the HA/beta-TCP ratio. Hence, the bioreactivity of BCP bioceramics can be controlled by manipulating the composition (HA/beta-TCP ratio) and/or the crystallinity of the BCP. Currently, BCP bioceramics is recommended for use as an alternative or additive to autogeneous bone for orthopedic and dental applications. It is available in the form of particulates, blocks, customized designs for specific applications and as an injectible biomaterial in a polymer carrier. BCP ceramic can be used also as grit-blasting abrasive for grit-blasting to modify implant substrate surfaces. Exploratory studies demonstrate the potential uses of BCP ceramic as scaffold for tissue engineering, drug delivery system and carrier of growth factors.
Takuo Fujita - One of the best experts on this subject based on the ideXlab platform.
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Calcium paradox consequences of Calcium Deficiency manifested by a wide variety of diseases
Journal of Bone and Mineral Metabolism, 2000Co-Authors: Takuo FujitaAbstract:Calcium Deficiency is a global problem, especially in the aging population. Among various nutrients, Calcium is one of the few that is still deficient in industrialized countries such as Japan and many Western countries. Calcium Deficiency is readily connected with osteoporosis, which is a decrease of bone Calcium content. Less well known is the Calcium outflow from bone that occurs to prevent decrease of blood Calcium in Calcium Deficiency caused by the parathyroid hormone, with consequent Calcium overflow into soft tissues and the intracellular compartment. Such intracellular paradoxical Ca overload as a consequence of nutritional Calcium Deficiency may give rise to a number of diseases common in old age: hypertension, arteriosclerosis, diabetes mellitus, neurodegenerative diseases, malignancy, and degenerative joint disease.
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Calcium paradox disease Calcium Deficiency prompting secondary hyperparathyroidism and cellular Calcium overload
Journal of Bone and Mineral Metabolism, 2000Co-Authors: Takuo Fujita, Genaro M A PalmieriAbstract:The consequences of such Ca overload in response to Ca Deficiency, which can be called Ca Deficiency disease or Ca paradox disease, to be more explicit, include osteoporosis, hypertension, arteriosclerosis, degenerating diseases of the central nervous system such as Alzheimer’s disease, diabetes mellitus, muscular dystrophy, and malignancy, especially colorectal carcinoma. In this review, evidence supporting the concept of Calcium paradox disease is presented from the viewpoints of epidemiology, clinical evidence, experimental models, and cell biology.
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degenerative joint disease an example of Calcium paradox
Journal of Bone and Mineral Metabolism, 1998Co-Authors: Takuo FujitaAbstract:Osteoporosis and degenerative arthropathy such as osteoarthritis and spondylosis deformans represent the two most common diseases seen in later life, sharing some common clinical features such as pain, deformity, and restriction of motion. Augmented bone resorption, possibly mediated by cytokines such as interleukin 1, and favorable therapeutic response to estrogen also characterize both diseases. Both osteoarthritis of the knee and osteoporosis occur frequently in postmenopausal women, whereas spondylosis deformans mainly affects men who experienced a heavy labor load, and women are less susceptible unless they worked as hard as men at some time in their lives. Degeneration of the cartilage with decrease of water content, increase of Calcium content, hardening, and subsequent wear and loss would lead to narrowing of the joint space and direct contact of bones, resulting in excessive reactive bone formation such as osteophytes. Because increased physical load on the cartilage and bone would intensify such response, excessive weight and physical exercise always remain important risk factors for degenerative joint disease. The metabolic state precipitating cartilage degeneration, however, may be even more important as the background. Calcium is confined to bone so long as adequate Calcium intake is maintained and the hormonal environment remains intact. When Calcium Deficiency and secondary hyperparathyroidism occur in old age, Calcium comes out of bone and starts to accumulate in soft tissues such as blood vessels, brain, and intracellular compartments, where little Calcium should be present under normal physiological circumstances. Cartilage should also be devoid of Calcium in health, but Calcium may accumulate when bone loss occurs in response to estrogen Deficiency, Calcium Deficiency, and secondary hyperparathyroidism. Calcium overabundance prompted by Calcium Deficiency is known as the Calcium paradox. Degenerative joint disease should be included in the group of diseases based on Calcium Deficiency and Calcium paradox, such as hypertension, arteriosclerosis, Alzheimer's disease and other degenerative diseases of the nervous system, diabetes mellitus, and malignancy. Calcium Deficiency is thus responsible for both osteoporosis and degenerative joint disease.
J M F Ferreira - One of the best experts on this subject based on the ideXlab platform.
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influence of mg doping Calcium pyrophosphate impurities and cooling rate on the allotropic α β triCalcium phosphate phase transformations
Journal of The European Ceramic Society, 2016Co-Authors: Paula M C Torres, J C C Abrantes, Ajay Kaushal, S Pina, Nicola Dobelin, Marc Bohner, J M F FerreiraAbstract:Abstract Alpha and beta-triCalcium phosphates are allotropic phases which play a very important role as bone graft substitutes, namely in Calcium phosphate cements. Despite extensive research efforts, contradictory reports exist on the importance of quenching for maintaining α-TCP purity. The role of Calcium pyrophosphate impurities derived from a certain Calcium-Deficiency, hydroxyapatite impurities derived from Calcium excess, and various ionic substitutions on thermal stability of these phases was not yet fully disclosed. The present work reports on the kinetics of α ↔ β-TCP phase transformations of Calcium-deficient TCP powders with different Mg-doping extents (0–5 mol%) prepared by precipitation. Mg clearly enhanced the thermal stability of β-TCP. The effect of cooling rate was more complex and interdependent on the Mg content and the heat treatment schedule. High α-TCP contents were retained upon cooling at 5 °C min −1 for Mg ≤ 1 mol% or upon quenching from 1550 °C for Mg contents ≤2 mol%.
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effect of ca p ratio of precursors on the formation of different Calcium apatitic ceramics an x ray diffraction study
Scripta Materialia, 2005Co-Authors: S Kannan, J H G Rocha, J M G Ventura, A F Lemos, J M F FerreiraAbstract:Abstract Biphasic ceramic mixtures of different hydroxyapatite and β-triCalciumphosphate (β-TCP) ratios and single phase β-TCP were prepared by a wet chemical process by adjusting the initial Ca/P ratios of the precursors under constant pH and temperature conditions. Increasing Calcium Deficiency led to a gradual increase in β-TCP content of the mixtures.
