Duodenal Expression of 25 Hydroxyvitamin D3-1α-hydroxylase Is Higher in Adolescents Than in Children and Adults.

Context: Puberty is associated with increased dietary calcium absorption. However, little is known about the metabolic adaptations that enhance calcium absorption during puberty.

Objectives: To investigate duodenal 25-hydroxy vitamin D-1α-hydroxylase (CYP 27B1) mRNA expression and duodenal 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) production in children, adolescents, and adults.

A single-unit design structure and gender differences in the swimming world championships.

Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs) can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed.

The role of vitamin D receptor in innate and adaptive immunity: a study in hereditary vitamin D-resistant rickets patients.

Context: Vitamin D has regulatory effects on innate and adaptive immunity. Curiously, hereditary vitamin D-resistant rickets (HVDRR) patients show no increased incidence of infectious or autoimmune diseases.

Objectives: The aim of the study was to investigate the role of vitamin D and the vitamin D receptor (VDR) in innate and adaptive immune responses in monocytes and lymphocytes from HVDRR patients.

Experimental versus evaluation unit and multiplicity problem in cell biology study.

Yizraeli and Weihs, Cell Biochem Biophys, 61: 605-618, 2011 evaluated the effect of electrical treatment on proliferative metabolic-activity of three experimental cell conditions. They reported, that the "..

Constant and variable stiffness and damping of the leg joints in human hopping.

The present study deals with the stiffness and damping profiles of the leg joints during the ground-contact phase of hopping. A two-dimensional (sagittal plane) jumping model, consisting of four linked rigid segments and including the paired feet, shanks, thighs, and the head-arms-trunk segment, was developed. The segments were interconnected by damped torsional springs, representing the action of the muscles, tendons and ligaments across the joint and of the other joint tissues.

Dynamic loading on the human musculoskeletal system -- effect of fatigue.

OBJECTIVE: A study was conducted to investigate the effects of fatigue on the ability of human musculoskeletal system to deal with the onslaught of the heel strike initiated shock waves. DESIGN: Running on a treadmill at the anaerobic threshold level for 30 min was used to acquire the experimental data on the foot strike initiated shock waves. BACKGROUND: Muscles act to lower the bending stress on bone and to attenuate the dynamic load on human musculoskeletal system.

Shock Transmission and Fatigue in Human Running.

The goal of this research was to analyze the effects of fatigue on the shock waves generated by foot strike. Twenty-two subjects were instrumented with an externally attached, lightweight accelerometer placed over the tibial tuberosity. The subjects ran on a treadmill for 30 min at a speed near their anaerobic threshold.