Test-retest reliability of knee kinesthesia in healthy adults

Background  

Sensory information from mechanoreceptors in the skin, muscles, tendons, and joint structures plays an important role in joint stability. A joint injury can lead to disruption of the sensory system, which can be measured by proprioceptive acuity. When evaluating proprioception, assessment tools need to be reliable. The aim of this study was to assess the test-retest reliability of a device designed to measure knee proprioception.     

Polymorphisms in the calcineurin genes are associated with the training responsiveness of cardiac phenotypes in Chinese young adults

We studied the association of 55 polymorphisms in the PPP3CA, PPP3CB, PPP3CC, PPP3R1 and PPP3R2 genes with both (1) the pre-training levels and (2) responsiveness to endurance training (18 weeks), of echocardiographic variables. The latter were measured both before and after the training program at each of the following time points: before (rest), during and after cycle-ergometry exercise. Subjects were healthy young Chinese men of Han origin [n = 102; mean (SD) age: 19 ± 1 years]. To assess genotype:phenotype associations at pre-training, we used a one-factor (genotype) ANOVA for each polymorphism. To assess the association between each polymorphism and the training responsiveness of cardiac phenotypes, we used a two-factor (genotype x training) ANOVA with repeated measures. All multiple comparisons were corrected for mass significance. For genotype:phenotype associations at pre-training, we only found a significant association between the rs3763679 polymorphism (PPP3CB) and resting heart rate. As for genotype associations with trainability of cardiac phenotypes, we found the following significant associations (i.e. significant genotype × training interaction effect): (1) rs1879793, rs1075534, rs7430, rs2461483 and rs10108011 (PPP3CC) and cardiac output/stroke volume after exercise; and (2) rs1407877 (PPP3R2) and ejection fraction at 50 W. The findings suggest that polymorphisms in the calcineurin genes might be among the numerous potential genetic variant candidates that can help explaining human variations in the pre-training levels or trainability of cardiac phenotype traits.     

Overweight, obesity and body fat composition in spanish adolescents. The AVENA Study

OBJECTIVE: To describe the prevalence of overweight and obesity in the Spanish adolescent population and its relationship with the socioeconomic status, and to assess their body fat composition and compare these results with previous data from our own country. DESIGN: Cross-sectional multicenter study conducted in five Spanish cities (Granada, Madrid, Murcia, Santander and Zaragoza) in 2000-2002. SUBJECTS: 2,320 adolescents with complete set of anthropometric measurements, 1,192 boys and 1,128 girls. MEASUREMENTS: Body mass index calculated from weight and height measurements, and body fat percentage calculated from skinfold thickness measurements. RESULTS: Overweight + obesity prevalences were 25.69 and 19.13% in boys and girls, respectively. Overweight + obesity prevalence increased in boys from high to medium-low socioeconomic status categories (p = 0.015); meanwhile, there was not a significant effect of socioeconomic status in girls. In males, overweight + obesity prevalence changed from 1985 to 2000-2002 from 13 to 35% and in females from 16 to 32%. The rate of change in overweight + obesity prevalences seems to increase in the last years; from 0.88 (1985 to 1995) to 2.33%/year (1995 to 2000-2002) in males and from 0.5 (1985 to 1995) to 1.83%/year (1995 to 2000-2002) in females. The rate of body fat percentage increase was similar between 1980 and 1995 and between 1995 and 2000-2002: 0.26 and 0.23%/year, respectively, at 13 years of age, and 0.16 and 0.17%/year, respectively, at 14 years of age. CONCLUSION: We observed elevated overweight and obesity prevalences in Spanish adolescents, similar to those observed in other European countries. There is a significant inverse relationship between socioeconomic status and overweight + obesity, but only in boys. The rate of change in overweight prevalence in Spanish adolescents seems to increase, and the rate of increase of body fat percentage seems to be similar as in previous years.     

Hif-1α and Hif-2α synergize to suppress AML development but are dispensable for disease maintenance

Leukemogenesis occurs under hypoxic conditions within the bone marrow (BM). Knockdown of key mediators of cellular responses to hypoxia with shRNA, namely hypoxia-inducible factor-1α (HIF-1α) or HIF-2α, in human acute myeloid leukemia (AML) samples results in their apoptosis and inability to engraft, implicating HIF-1α or HIF-2α as therapeutic targets. However, genetic deletion of Hif-1α has no effect on mouse AML maintenance and may accelerate disease development. Here, we report the impact of conditional genetic deletion of Hif-2α or both Hif-1α and Hif-2α at different stages of leukemogenesis in mice. Deletion of Hif-2α accelerates development of leukemic stem cells (LSCs) and shortens AML latency initiated by Mll-AF9 and its downstream effectors Meis1 and Hoxa9. Notably, the accelerated initiation of AML caused by Hif-2α deletion is further potentiated by Hif-1α codeletion. However, established LSCs lacking Hif-2α or both Hif-1α and Hif-2α propagate AML with the same latency as wild-type LSCs. Furthermore, pharmacological inhibition of the HIF pathway or HIF-2α knockout using the lentiviral CRISPR-Cas9 system in human established leukemic cells with MLL-AF9 translocation have no impact on their functions. We therefore conclude that although Hif-1α and Hif-2α synergize to suppress the development of AML, they are not required for LSC maintenance.Oxygen measurement in the BM indicated that normal and malignant hematopoiesis occur under hypoxic conditions (Spencer et al., 2014). Hif-1 and Hif-2 are key mediators of cellular responses to hypoxia and regulate gene expression to facilitate adaptation to low oxygen tension (Semenza, 2014). Oxygen-regulated α-subunits of Hif-1 and Hif-2, namely Hif-1α and Hif-2α, are paralogs that have common and also distinct functions during responses to hypoxia. Several studies investigated the role of Hif-1α (Wang et al., 2011; Velasco-Hernandez et al., 2014) and Hif-2α (Rouault-Pierre et al., 2013) in acute myeloid leukemia (AML; Gezer et al., 2014; Vyas, 2014). HIF-1α or HIF-2α knockdown in AML patient samples compromised their ability to reconstitute AML upon transplantation into recipient mice (Wang et al., 2011; Rouault-Pierre et al., 2013). Although the subtype and molecular classification of AML samples used in these studies were not specified, the authors implied that HIF-1 and HIF-2 are independently required for the maintenance of AML leukemic stem cells (LSCs), suggesting that HIF-1 and HIF-2 are potential therapeutic targets for AML (Wang et al., 2011; Rouault-Pierre et al., 2013).Considering the caveats of shRNA-mediated gene knockdown approaches, a recent study used a conditional Hif-1α knockout and reported that, surprisingly, conditional Hif-1α deletion does not compromise the development and maintenance of mouse LSCs generated by the MLL-ENL fusion, its downstream effectors Meis1 and Hoxa9, and Aml1-Eto9a (Velasco-Hernandez et al., 2014). In fact, loss of Hif-1α accelerated the development of Meis1/Hoxa9-induced AML or enhanced propagation of disease induced by Aml1-Eto9a (Velasco-Hernandez et al., 2014). This study concluded that Hif-1α can suppress LSC development or propagation and is dispensable for AML LSC maintenance, sparking a debate over the therapeutic benefit of targeting HIF-1 function (Vyas, 2014).To date, the impact of conditional deletion of Hif-2α or loss of both Hif-1α and Hif-2α on leukemic transformation has not been examined. Therefore, in this study, we set out to investigate the requirement for Hif-2α or both Hif-1α and Hif-2α in the development and maintenance of AML LSCs.     

Hand span influences optimal grip span in boys and girls aged 6 to 12 years

PURPOSE: The first aim was to determine whether there is an optimal grip span for determining the maximum hand grip strength in boys and girls aged 6 to 12 years and whether the optimal grip span was related to hand span. If so, the second aim was to derive a mathematical equation relating hand span and optimal grip span. METHODS: A total of 123 boys (9 y +/- 2) and 70 girls (8 y +/- 2) were evaluated. Each hand was randomly tested on 10 occasions using 5 different grip spans, allowing a 1-minute rest between attempts. The hand span was measured from the tip of the thumb to the tip of the little finger with the hand opened widely. RESULTS: An optimal grip span to determine maximum hand grip strength was identified for both genders. Hand span and optimal grip span showed a significant linear association in the studied children. The equation relating grip span as a function of hand span in boys is formulated as y = x/4 + 0.44 and in girls as y = 0.3x - 0.52, where x is the hand span (maximal width between first and fifth fingers) and y is the optimal grip span. CONCLUSIONS: The results suggest that there is an optimal grip span to which the dynamometer should be adjusted when measuring hand grip strength in children. The optimal grip span was influenced by hand span in both genders.