7 Clinical Trials for Various Conditions
The study outlined is designed to measure and to determine whether the combined use of vitamin D2 (ergocalciferoI) and 1-alpha-hydroxyvitamin D2 (doxercalciferol)) or doxercalciferol alone will correct the mineralization defect in pediatric patients with established secondary hyperparathyroidism (2°HPT) undergoing regular peritoneal dialysis. Serum phosphorus levels will be controlled with a calcium¬-free-metal free phosphate binder; (obtained at baseline and after 8 months of treatment) sevelamer. Indices of bone mineralization obtained at baseline and after 8 months of treatment will be measured by quantitative histomorphometry in iliac crest bone biopsies after double tetracycline labeling. Immunohistochemistry will be done in specimens of bone biopsies from iliac crest to examine the expression for selected markers of bone turnover and mineralization such as FGF-23, DMP1, MEPE and OPG. Serum PTH levels will be measured with the 1st and 2nd generation immunometric assay (PTH-IMAs) and fibroblast growth factor-23 (FGF-23) will be determined by one assay with specific detection antibodies that are against epitopes within the C-terminus of FGF-23 and another assay that uses antibodies against epitopes within the N- and C-terminal portions of the molecule respectively. The value of non-invasive assessment of bone mass by quantitative computed tomography (QCT) and its relationship with vascular disease determined by ultrasound (US) of intimal carotid thickness (CIMT) will be correlated with bone histomorphometry and the different biochemical determinations.
Maximizing calcium retention by the skeleton within the genetic potential is a key strategy to prevent osteoporosis. It has been shown that calcium retention varies between blacks and whites and between gender within race. This study is designed to study the relationship between calcium intakes and calcium retention in Asian adolescent girls and boys. It is hypothesized that calcium intakes which maximize calcium retention will be lower in Asians than for whites studies under the same conditions. In addition it is thought that the differences between races in the physiological mechanisms involved in calcium metabolism will result in a lower calcium intake required to observe a plateau in calcium retention. This is turn could be translated into lower calcium requirements in Asians relative to Caucasians for achieving optimal peak bone mass.
Fructooligosaccharides (FOS) are believed to have positive effects on calcium absorption and bone accrual during growth. This study aims to see whether the addition of fiber in the form of FOS to a calcium-containing beverage will increase calcium absorption. During two clinical visits, participants will receive a beverage containing a small amount of calcium, supplemented with either no dietary fiber or a small amount of fiber. Height, weight, bone density and geometry, calcium absorption, and physical fitness will be measured. The effects of this fiber intervention may provide support for improving bone health with minimal fiber supplementation.
Building stronger bones during pubertal growth could reduce lifelong fracture risk. This project is an 18 month dairy intervention study for overweight and healthy weight 4th-8th grade boys and girls. Half of the girls will receive dairy products to add to their habitual diet (milk, yogurt, and cheese) to equal three products per day, while the other half will remain on their normal diet. All participants will attend four study visits, each 6 months apart. At these visits height, weight, bone density and geometry, and fat and lean mass will be measured. This study aims to show that meeting calcium requirements by eating dairy products builds bigger, stronger bones, and that this effect may be enhanced in overweight boys and girls. The effect of the dairy intervention on body fat, lean mass, and weight, as well as the mechanisms and predictors of changes in bone mass and size and body composition will also be evaluated.
The purpose of the study is to evaluate the effects of different dietary calcium have on the pregnant teen mother and her newborn. We hypothesize that the higher calcium intake during pregnancy will result in higher bone mass in the newborn.
The goal of this project is to develop a new noninvasive ultrasound based technique, called vibro-acoustic analysis (VAA), for evaluation of infant bone health with particular application in assessment of bone health in premature infants who are at risk for bone disease.
This PXE biomarker study aims to characterize the levels of inorganic pyrophosphate (PPi), pyridoxal 5´-phosphate (PLP), and other biomarkers relevant to PXE and ectopic calcification in both PXE patients and their biological siblings who are PXE carriers or normal non-PXE individuals.