Physical fitness (PF) is a construct of health‐ and skill‐related attributes which have been associated with academic performance (AP) in youth. This study aimed to review the scientific evidence on the association among components of PF and AP in children and adolescents. A systematic review of articles using databases PubMed/Medline, ERIC, LILACS, SciELO, and Web of Science was undertaken. Cross‐sectional and longitudinal studies examining the association between at least one component of PF and AP in children and adolescents, published between 1990 and June 2016, were included. Independent extraction of articles was carried out by the two authors using predefined data fields. From a total of 45 studies included, 25 report a positive association between components of PF with AP and 20 describe a single association between cardiorespiratory fitness (CRF) and AP. According to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines: 12 were classified as low, 32 as medium risk, and 1 as high risk of bias. Thirty‐one studies reported a positive association between AP and CRF, six studies with muscular strength, three studies with flexibility, and seven studies reported a positive association between clustered of PF components and AP. The magnitude of the associations is weak to moderate (β = 0.10–0.42 and odds = 1.01–4.14). There is strong evidence for a positive association between CRF and cluster of PF with AP in cross‐sectional studies; and evidence from longitudinal studies for a positive association between cluster of PF and AP; the relationship between muscular strength and flexibility with AP remains uncertain.

Previous studies have found that obesity could influence academic performance. The aim of this study was to systematically review the scientific evidence on the association between obesity and academic performance in school children. A systematic review of English articles was undertaken by using databases PubMed/Medline, ERIC, LILACS, SciELO and Web of Science. Cross-sectional and longitudinal studies examining the association between obesity and academic performance in children and adolescents, published between January 1990 and December 2016, were included. Risk of bias was assessed by using Strengthening the Reporting of Observational Studies in Epidemiology. Thirty-four studies (23 cross-sectional and 11 longitudinal) matched all inclusion criteria and were included. Seven studies were classified as low risk of bias, 23 as medium risk and four as high risk. After controlling for covariates such as socio-economic status, parental education and physical activity, the association between obesity and academic performance becomes uncertain for most of the studies (55.9%). Therefore, at present, there is insufficient evidence to support a direct link between obesity and poor academic performance in school age children. In order to clarify this issue, we need more longitudinal studies with adequate sample sizes and that control for potential confounders.

Membrane receptors for the Fc portion of immunoglobulin G (IgG) antibodies (Fc(gamma)Rs) are expressed on almost every type of hematopoietic cells, where they mediate a wide variety of effector functions. A high degree of structural heterogeneity exists among Fc(gamma)Rs. The biological significance of such heterogeneity is unknown, since the structural diversity does not appear to be reflected in the binding specificity nor in the effector functions that each distinct receptor is able to mediate. Recent work has emphasized the essential role of protein tyrosine phosphorylation in the initiation of transmembrane signaling by these receptors. In this article we review the role of protein tyrosine phosphorylation in signal transduction by the different types of Fc(gamma)Rs in order to assess to what extent the structural heterogeneity of this receptor family is related to different activation pathways utilized by each of its members.

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This study aims to portray the complex diversity of the Mexican Mestizo population, which represents 98.8% of the entire population of Mexico. We compiled extended haplotype data of the Y chromosome from populations in the Central Valley of Mexico (CVM), which were compared to other Mestizo and parental (Amerindian, European and African) populations. A complex ancestral relationship was found in the CVM population, suggesting cosmopolitan origins.Nevertheless, the most preeminent lineages point towards a European ancestry, where the R1b was the most frequent. In addition, important frequencies of Amerindian linages were also found in the Mestizo sample studied. Interestingly, the Amerindian ancestry showed a remarkable substructure, which was represented by the two main founding lineages: QL54 (x M3) and M3. However, even within each lineage a high diversity was found despite the small number of samples bearers of these lineages. Further, we detected important genetic differences between the CVM populations and the Mexican Mestizo populations from the north and south. This result points to the fact that Mestizo populations present different ancestral proportions, which are related to the demographic events that gave origin to each population. Finally, we provide additional forensic statistical parameters that are useful in the interpretation of genetic analysis where autosomal loci are limited. Our findings illustrate the complex genetic background 3 of the Mexican Mestizo population and reinforce the need to encompass more geographic regions to generate more robust data for forensic applications. Materials and Methods Population of studyBlood samples were collected from 231 unrelated men belonging to the Mexican Mestizo population having at least three generations of ancestors born in Mexico.The studied population was recruited from Mestizos living in the Central Valley of the country (North-Central and East-Central regions) (Figure 1). This population included 121 men from Querétaro and 63 men from Guanajuato (North-Central region), as well as 47 men from Puebla (East-Central region). 7Each individual signed an informed consent validated by the Ethics Committee of the Bimodi's Research Unit. In addition, genealogical data were also obtained from each person to ensure that the individuals were unrelated through at least three generations. Molecular Analysis Y-chromosome haplotypingGenomic DNA was extracted from peripheral blood leukocytes using Qiamp Statistical and phylogenetic analysis8 Population genetics parametersAllele and haplotype frequencies, number of alleles (k), haplotype diversity (HD), genetic diversity over loci (h), and mean pairwise differences were estimated using Arlequin v. 3.5 software (Excoffie et al. 2010). Number of unique haplotypes (nuh) was estimated by direct counting. The following forensic parameters were determined: discrimination capacity (DC) was calculated by the expression: DC=h/n, where "h" is the total number of different haplotypes and "n"is the total number of i...

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Since Mexican mestizos are an admixed population, it is necessary to determine the effects that the substructure of the population has on genetic and forensic parameters. With this aim, a study was performed with 15 STR loci (CODIS plus D2S1338 and D19S433) on 1,640 unrelated Mexican mestizos. We determine allele and genotypic frequencies observing departure from Hardy-Weinberg expectation (12 out of 15 loci, with an excess of homozygotes, Fis > 0), as well as pairs of loci in an apparent linkage disequilibrium (13 of 92 loci). We conducted a test for genetic population stratification, the results show that the Mexican mestizo population is substructured into three subgroups, which are in HW and linkage equilibrium. The combination of the 15 loci in the whole population has high forensic efficiency with the capacity to genetically discriminate one individual in one quintillion (1/10(18)). Our data potentially validates the use of these 15 STR loci to establish forensic identity and parentage testing for legal purposes, and offers a powerful tool for genetic variation analysis. However, given that the population is stratified, we highly recommend applying a correction with the inbreeding coefficient in calculations of paternity and forensic studies to avoid erroneous assumptions.

Objective. Venous thromboembolism (VTE) is a multifactorial disorder and, worldwide, the most important cause of morbidity and mortality. Genetic factors play a critical role in its aetiology. Microsatellites are the most important source of human genetic variation having more phenotypic effect than many single nucleotide polymorphisms. Hence, we evaluate a possible relationship between VTE and the genetic variants in von Willebrand factor, human alpha fibrinogen, and human thyroid peroxidase microsatellites to identify possible diagnostic markers. Methods. Genotypes were obtained from 177 patients with VTE and 531 nonrelated individuals using validated genotyping methods. The allelic frequencies were compared; Bayesian methods were used to correct population stratification to avoid spurious associations. Results. The vWA-18, TPOX-9, and TPOX-12 alleles were significantly associated with VTE. Moreover, subjects bearing the combination vWA-18/TPOX-12 loci exhibited doubled risk for VTE (95% CI = 1.02–3.64), whereas the combination vWA-18/TPOX-9 showed an OR = 10 (95% CI = 4.93–21.49). Conclusions. The vWA and TPOX microsatellites are good candidate biomarkers in venous thromboembolism diseases and could help to elucidate their origins. Additionally, these polymorphisms could become useful markers for genetic studies of VTE in the Mexican population; however, further studies should be done owing that this data only show preliminary evidence.