Oral calcium carbonate affects calcium but not phosphorus balance in stage 3-4 chronic kidney disease.

Patients with chronic kidney disease (CKD) are given calcium carbonate to bind dietary phosphorus, reduce phosphorus retention, and prevent negative calcium balance; however, data are limited on calcium and phosphorus balance during CKD to support this. Here, we studied eight patients with stage 3 or 4 CKD (mean estimated glomerular filtration rate 36 ml/min) who received a controlled diet with or without a calcium carbonate supplement (1500 mg/day calcium) during two 3-week balance periods in a randomized placebo-controlled cross-over design. All feces and urine were collected during weeks 2 and 3 of each balance period and fasting blood, and urine was collected at baseline and at the end of each week.

Bone turnover is not influenced by serum 25-hydroxyvitamin D in pubertal healthy black and white children.

Low serum 25-hydroxyvitamin D [25 (OH) D] is common in healthy children particularly in blacks. However, serum 25 (OH) D concentrations for optimal bone turnover in children is unknown and few data exist that describe effects of increasing serum 25 (OH) D on bone turnover markers during puberty. The purpose of this study was to determine the relationships between serum 25 (OH) D and changes in serum 25 (OH) D and bone turnover in white and black pubertal adolescents.

Top food sources contributing to vitamin D intake and the association of ready-to-eat cereal and breakfast consumption habits to vitamin D intake in Canadians and United States Americans.

Unlabelled: This study aimed to determine dietary vitamin D intake of U.S. Americans and Canadians and contributions of food sources to total vitamin D intake.

Serum leptin, parathyroid hormone, 1,25-dihydroxyvitamin D, fibroblast growth factor 23, bone alkaline phosphatase, and sclerostin relationships in obesity.

Background: Obesity is associated with hyperparathyroidism and increased bone mass and turnover, but their pathogeneses are unclear.

Aims: Our aim was to determine in obesity interrelationships among serum levels of leptin, the mineral-regulating hormones, bone turnover markers, and sclerostin.

Methods: This case-control study was performed in 20 women having bariatric surgery and 20 control women matched for race and age.

Effect of calcium carbonate particle size on calcium absorption and retention in adolescent girls.

Objective: Increasing calcium bioavailability by decreasing calcium salt particle size in the supplement may be one way to increase calcium absorption. The aim of the study was to compare (1) large versus small particle size CaCO(3) supplements and (2) small particle size CaCO(3) supplement versus placebo on calcium absorption and retention in adolescent girls.

Methods: Thirty-one adolescent girls, aged 11 to 14 years, participated in two 3-week calcium balance periods separated by a 1-week washout period.

Obesity augments calcium-induced increases in skeletal calcium retention in adolescents.

Context: Overweight adolescents have low bone mineral content for weight and are at increased risk for fractures.

Objective: The aim was to determine whether overweight and obesity influence the positive relationship between dietary calcium intake and skeletal calcium retention in adolescents.

Design: Analysis of pooled data from calcium balance studies in adolescents.

Pre-Workout Carbohydrate Supplementation does not Affect Measures of Selfassessed Vitality and Affect in College Swimmers.

Beneficial effects of dietary carbohydrate (CHO) on physical and psychological parameters have been demonstrated in athletes. Because affect, or mood, can predict athletic performace, the main objective of this study was to determine the effect of pre-workout CHO on affect in swimmers. College swimmers (n = 37) participated in a randomized crossover experiment of the effects of a pre-workout CHO supplement on vitality and affect.

Daily supplementation with 25 μg cholecalciferol does not increase calcium absorption or skeletal retention in adolescent girls with low serum 25-hydroxyvitamin D.

In healthy adolescents, cross-sectional studies show either no or negative relationships between serum 25-hydroxyvitamin D [25(OH)D] and calcium (Ca) absorption. Using a 2-period metabolic balance study, the effect of vitamin D supplementation on Ca absorption and retention in adolescent girls was investigated. Eleven girls aged 12-14 y with a mean entry serum 25(OH)D of 35.

An inflection point of serum 25-hydroxyvitamin D for maximal suppression of parathyroid hormone is not evident from multi-site pooled data in children and adolescents.

In adults, maximal suppression of serum parathyroid hormone (PTH) has commonly been used to determine the sufficiency of serum 25-hydroxyvitamin D [25(OH)D]. In children and adolescents, the relationship between serum 25(OH)D and PTH is less clear and most studies reporting a relationship are derived from relatively small samples and homogeneous cohorts. Our objective was to determine the relationship between serum 25(OH)D and PTH in children and adolescents from a large and diverse U.

Predictors of calcium retention in adolescent boys.

Context: The relationship between calcium (Ca) intake and Ca retention in adolescent boys was recently reported.

Objective: This study evaluated the influence of Ca intake, serum hormone levels, biomarkers of bone metabolism, habitual physical activity, habitual Ca intake, and physical fitness on Ca retention in the same sample.

Design: This study was a randomized, cross-over design that consisted of two 3-wk metabolic balance periods.

Surgical repair of cardiac valves.

The mitral, aortic, and tricuspid valves can be repaired, in experienced hands. Durability of repair, especially for the mitral valve, compares favorably to valve replacement. Repair of cardiac valves enables many patients to be free of life-long anticoagulation, maintain their native valve structure, reduce their risk for endocarditis, and avoid complications associated with prosthetic valve implants.

Transcutaneous carbon dioxide monitoring.

Technologies now exist that measure carbon dioxide levels transcutaneously. Rapid assessment of patients who have depressed ventilation or suspected sepsis can improve treatment decisions including the need for admission to the ICU and pulmonary artery catheterization.

Surgery for paroxysmal atrial fibrillation in the setting of mitral valve disease: a role for pulmonary vein isolation?

Background: It is unknown whether pulmonary vein isolation or a complete Cox-Maze procedure is needed to ablate paroxysmal atrial fibrillation in patients with mitral valve disease. Our objective was to assess the impact of different surgical treatments for this arrhythmia in patients undergoing mitral valve surgery.

Methods: From July 1993 to January 2004, 152 patients underwent combined surgical treatment of paroxysmal atrial fibrillation and mitral valve disease.

Surgical ablation of atrial fibrillation with bipolar radiofrequency as the primary modality.

Objectives: In studying cardiac surgical patients undergoing atrial fibrillation ablation with bipolar radiofrequency, we sought to (1) quantify the time-related prevalence of atrial fibrillation postoperatively and identify its risk factors and (2) determine time-related ablation failure and its risk factors.

Methods: From November 2001 to January 2004, 513 patients underwent atrial fibrillation ablation (bipolar radiofrequency alone or with cryothermy) and other cardiac operations. Rhythm documented on 3495 postoperative electrocardiograms was used to estimate the prevalence of and risk factors for atrial fibrillation across time.