Effects of physical activity,fitness and fatness on children's body image: The Australian LOOK longitudinal study

BackgroundAmong children relationships between body image and body fat are well documented but less attention has been given to relationships with physical activity and fitness. This study examined longitudinal relationships of children's body image with physical activity, fitness and percent body fat whilst accounting for a number of potential confounding variables.MethodParticipants were 821 elementary-school children across 29 schools from the Lifestyle of our Kids (LOOK) study. Measures of body image, body fat (DXA), physical activity (pedometers) and fitness (shuttle run) were collected in grades two, four and six.ResultsThe current study found longitudinal evidence that increases in %BF among primary school-aged girls is associated with greater body dissatisfaction and cross-sectional evidence of the same relationship among boys. Among both boys and girls, lower levels of cardiovascular fitness were associated with greater body dissatisfaction cross-sectionally, even after adjusting for percent body fat. Weaker evidence was found for the relationship between physical activity and body dissatisfaction and these relationships were no longer significant after adjusting for percent body fat. At the between-school level we found significant and positive relationships between body dissatisfaction and physical activity among girls and with percent body fat for boys, indicating that school culture may significantly affect body dissatisfaction.ConclusionIncreased adiposity is a strong predictor of body dissatisfaction, particularly among girls. Higher levels of cardiovascular fitness may act as a protective buffer to body image concerns, regardless of a child's body composition. Future interventions may benefit from targeting change in school culture.     

Deformability and cell membrane properties of erythrocytes in Duchenne muscular dystrophy

In many investigations of the hypothesis of a membrane defect in Duchenne muscular dystrophy, the erythrocyte has been the cell of choice, but reported abnormalities in the Duchenne erythrocyte are disputed. Techniques of microsieving, cell surface staining and measurement of cell water diffusion turnover rate have been used in this investigation to examine erythrocyte properties. Measurements of pressure drop-velocity relations were carried out in a capillary pore rheometer using pure erythrocyte suspensions. The study showed that Duchenne erythrocytes do not behave differently from normal, results which are in substantial agreement with similar microsieving studies. A nuclear magnetic resonance method was used to measure cell water diffusion efflux which, using our cell surface data, could be related to cell membrane permeability. Under normal conditions and conditions of chemical interference with the membrane protein, the results revealed that the membrane pathways involved in water diffusion in Duchenne erythrocytes are unaltered.     

Toxicologic studies with japanese quail fed winter wheat grown on municipal sludge-amended soil

Winter wheat was grown on soil amended with 100 dry tons per acre (224 metric tons/ha) of municipal sewage sludge from Syracuse, New York. The grain contained 1.43 and 0.98 ppm (mg/kg) dry weight, respectively, of cadmium and nickel. This wheat was incorporated as 60% of a semi-synthetic diet and fed to male and female Japanese quail for two generations. Male quail from the F₁ generation fed sludge-grown wheat showed induction of hepatic microsomal enzymes,i.e., aminopyrene-N-demethylase and aniline hydroxylase, that indicated foreign compounds present in the wheat. Cadmium was significantly higher (p < 0.05) than controls in kidney, liver, and testes and nickel in the liver of the male quail (F₀) fed the sludge-grown grain. Cadmium in kidney and liver (but not in eggs) and nickel in liver was significantly higher (p < 0.05) than controls in the females fed the sludge-grown wheat. Birds from the F₁ generation showed no significantly different (p > 0.05) concentrations of cadmium in kidney, liver, or eggs between the two dietary treatments. There were no observable changes in the tissue ultrastructure of liver and kidney as examined by electron microscopy in any of the treatment groups.     

Glucocorticoids and irradiation-induced apoptosis in normal murine bone marrow B-lineage lymphocytes as determined by flow cytometry.

A substantial proportion of murine bone marrow B220+ and IgM+ cells were induced to undergo apoptosis when exposed to glucocorticoids or ionizing radiation in vitro. Two-colour flow cytometric analysis of the cell cycle indicated that a distinct subpopulation of cells formed to the left of G0/G1 in the hypodiploid or Ao region previously shown to contain apoptotic cells with fragmented DNA. Indeed, 45-65% of all B220+ or IgM+ cells of the marrow were found in this apoptotic region 12 hr after treatment with dexamethasone (Dex) or exposure to 500 rads of irradiation. Zinc sulphate, a frequently cited inhibitor of apoptosis, prevented accumulation of cells exposed to glucocorticoids or ionizing radiation in the Ao region as did the glucocorticoid receptor antagonist RU 38486. Although Dex was more potent, corticosterone and cortisol also induced significant degrees of apoptosis in B220+ and IgM+ marrow cells at physiological concentrations. These results demonstrate that freshly isolated B-lineage cells of the murine bone marrow readily undergo apoptosis upon exposure to glucocorticoids and ionizing radiation and suggest that apoptosis may play a role in the regulation of lymphopoiesis. The data also show the value of flow cytometry to the study of apoptosis in subsets of cells within a heterogenous population such as the bone marrow which heretofore was exceedingly difficult to evaluate.     

Heading judgments during active and passive self-motion

Previous studies have generally considered heading perception to be a visual task. However, since judgments of heading direction are required only during self-motion, there are several other relevant senses which could provide supplementary and, in some cases, necessary information to make accurate and precise judgments of the direction of self-motion. We assessed the contributions of several of these senses using tasks chosen to reflect the reference system used by each sensory modality. Head-pointing and rod-pointing tasks were performed in which subjects aligned either the head or an unseen pointer with the direction of motion during whole body linear motion. Passive visual and vestibular stimulation was generated by accelerating subjects at sub- or supravestibular thresholds down a linear track. The motor-kinesthetic system was stimulated by having subjects actively walk along the track. A helmet-mounted optical system, fixed either on the cart used to provide passive visual or vestibular information or on the walker used in the active walking conditions, provided a stereoscopic display of an optical flow field. Subjects could be positioned at any orientation relative to the heading, and heading judgments were obtained using unimodal visual, vestibular, or walking cues, or combined visual-vestibular and visual-walking cues. Vision alone resulted in reasonably precise and accurate head-pointing judgments (0.3° constant errors, 2.9° variable errors), but not rod-pointing judgments (3.5° constant errors, 5.9° variable errors). Concordant visual-walking stimulation slightly decreased the variable errors and reduced constant pointing errors to close to zero, while head-pointing errors were unaffected. Concordant visual-vestibular stimulation did not facilitate either response. Stimulation of the vestibular system in the absence of vision produced imprecise rod-pointing responses, while variable and constant pointing errors in the active walking condition were comparable to those obtained in the visual condition. During active self-motion, subjects made large headpointing undershoots when visual information was not available. These results suggest that while vision provides sufficient information to identify the heading direction, it cannot, in isolation, be used to guide the motor response required to point toward or move in the direction of self-motion.     

X-linked syndrome of platelet dysfunction, thrombocytopenia, and imbalanced globin chain synthesis with hemolysis

An unusual family is described with a congenital bleeding disorder present in four males belonging to three generations. Of the three surviving affected males, all had splenomegaly and petechiae. The three had moderate thrombocytopenia (55-90 X 10(9)/liter) and markedly prolonged Ivy-template bleeding times (greater than 30 min). They were also noted to have reticulocytosis and, upon further investigation, imbalanced globin chain synthesis resembling that of beta-thalassemia minor. Studies on nine additional family members in four generations were normal except for slight elevations of reticulocyte counts in female members, one of whom had the abnormal globin chain synthesis ratio. In male members, the bleeding tendency and clinical signs always occurred in the presence of the globin chain synthesis defect and reticulocytosis. This previously undescribed condition was apparently transmitted as an X-linked disorder.     

基于受体结构的药物分子设计系统:维甲类分子与其结合蛋白之间相互作用的研究

大分子解剖程序,配体分子契合适配和DOCK程序,以及计算化学的其它程序等,已集成为基于受体结构和分子间相互作用的进行分子设计的软件系统,定名为BIOS(Biomolecularinteractionsandorientationsimulator)。BIOS软件可在普通的微机上运行。使用BIOS分别剥离了细胞浆维甲结合蛋白(CRBP)和副睾维甲酸结合蛋白(E-RABP)两种蛋白的配体结合腔,剥离是围绕配体以同样的分子距离进行的。从而得到了芳香性残基分布相似的两个结合腔,其结合位点的几何排布却有相当差别。揭示出的结合腔已用于一系列的维甲类化合物的DOCK研究。E-RABP的结合腔可做为设计新维甲类分子的模板。