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31.
The study investigated the relationship between children’s hair-Al concentrations and children’s behavioral performance in school. Hair-Al levels of 102 children drawn from a general school population were correlated with teachers’ ratings of the children on the Walker Problem Behavior Identification Checklist (WPBIC). Increasing hair-Al values correlated significantly with increased scores on the WPBIC total scale score. A continuing reexamination of Al exposure in the young is needed in order to determine the margin of safety regarding potentially toxic levels of Al. 相似文献
32.
Natural killer (NK) cells and CD8(+) T cells play vital roles in containing and eliminating systemic cytomegalovirus (CMV). However, CMV has a tropism for the salivary gland acinar epithelial cells and persists in this organ for several weeks after primary infection. Here we characterize a distinct NK cell population that resides in the salivary gland, uncommon to any described to date, expressing both mature and immature NK cell markers. Using RORγt reporter mice and nude mice, we also show that the salivary gland NK cells are not lymphoid tissue inducer NK-like cells and are not thymic derived. During the course of murine cytomegalovirus (MCMV) infection, we found that salivary gland NK cells detect the infection and acquire activation markers, but have limited capacity to produce IFN-γ and degranulate. Salivary gland NK cell effector functions are not regulated by iNKT or T(reg) cells, which are mostly absent in the salivary gland. Additionally, we demonstrate that peripheral NK cells are not recruited to this organ even after the systemic infection has been controlled. Altogether, these results indicate that viral persistence and latency in the salivary glands may be due in part to the presence of unfit NK cells and the lack of recruitment of peripheral NK cells. 相似文献
33.
Using questionnaire data completed by 170 men, we examine variation in paternal investment in relation to the trade-off between
mating and parenting. We found that as men’s self-perceived mate value increases, so does their mating effort, and in turn,
as mating effort increases, paternal investment decreases. This study also simultaneously examined the influence on parental
investment of men’s mating effort, men’s perception of their mates’ fidelity, and their perceived resemblance to their offspring.
All predicted investment. The predictors of investment are also tested independently for men who are still in a relationship
with the mother of their children and those that are separated from her. Finally we examine how self-perceived mate value
affects how men respond to variation in paternity confidence. Men with a self-perceived low mate value were less likely to
respond to lowered mate fidelity by reducing their parental investment compared with men with a self-perceived high mate value. 相似文献
34.
35.
Frank Marlowe 《Human nature (Hawthorne, N.Y.)》1998,9(3):263-271
A new hypothesis is proposed to explain the perennially enlarged breasts of human females. The nubility hypothesis proposes that hominid females evolved protruding breasts because the size and shape of breasts function as an honest signal of residual reproductive value. Hominid females with greater residual reproductive value were preferred by males once reliable cues to ovulation were lost and long-term bonding evolved. This adaptation was favored because female-female competition for investing males increased once hominid males began to provide valuable resources. 相似文献
36.
37.
Frank W. Marlowe 《Human nature (Hawthorne, N.Y.)》2009,20(4):417-430
Strong reciprocity is an effective way to promote cooperation. This is especially true when one not only cooperates with cooperators and defects on defectors (second-party punishment) but even punishes those who defect on others (third-party, “altruistic” punishment). Some suggest we humans have a taste for such altruistic punishment and that this was important in the evolution of human cooperation. To assess this we need to look across a wide range of cultures. As part of a cross-cultural project, I played three experimental economics games with the Hadza, who are hunter-gatherers in Tanzania. The Hadza frequently engaged in second-party punishment but they rarely engaged in third-party punishment. Other small-scale societies engaged in less third-party punishment as well. I suggest third-party punishment only became more important in large, complex societies to solve more pressing collective-action problems. 相似文献
38.
Evolution of eutherian cytochrome c oxidase subunit II: heterogeneous rates of protein evolution and altered interaction with cytochrome c 总被引:2,自引:1,他引:2
Cytochrome c oxidase subunit II (COII), encoded by the mitochondrial
genome, exhibits one of the most heterogeneous rates of amino acid
replacement among placental mammals. Moreover, it has been demonstrated
that cytochrome c oxidase has undergone a structural change in higher
primates which has altered its physical interaction with cytochrome c. We
collected a large data set of COII sequences from several orders of mammals
with emphasis on primates, rodents, and artiodactyls. Using phylogenetic
hypotheses based on data independent of the COII gene, we demonstrated that
an increased number of amino acid replacements are concentrated among
higher primates. Incorporating approximate divergence dates derived from
the fossil record, we find that most of the change occurred independently
along the New World monkey lineage and in a rapid burst before apes and Old
World monkeys diverged. There is some evidence that Old World monkeys have
undergone a faster rate of nonsynonymous substitution than have apes. Rates
of substitution at four-fold degenerate sites in primates are relatively
homogeneous, indicating that the rate heterogeneity is restricted to
nondegenerate sites. Excluding the rate acceleration mentioned above,
primates, rodents, and artiodactyls have remarkably similar nonsynonymous
replacement rates. A different pattern is observed for transversions at
four-fold degenerate sites, for which rodents exhibit a higher rate of
replacement than do primates and artiodactyls. Finally, we hypothesize
specific amino acid replacements which may account for much of the
structural difference in cytochrome c oxidase between higher primates and
other mammals.
相似文献
39.
Immunity to the murine cytomegalovirus (MCMV) is critically dependent on the innate response for initial containment of viral replication, resolution of active infection, and proper induction of the adaptive phase of the anti-viral response. In contrast to NK cells, the Vα14 invariant natural killer T cell response to MCMV has not been examined. We found that Vα14i NK T cells become activated and produce significant levels of IFN-γ, but do not proliferate or produce IL-4 following MCMV infection. In vivo treatment with an anti-CD1d mAb and adoptive transfer of Vα14i NK T cells into MCMV-infected CD1d−/− mice demonstrate that CD1d is dispensable for Vα14i NK T cell activation. In contrast, both IFN-α/β and IL-12 are required for optimal activation. Vα14i NK T cell–derived IFN-γ is partially dependent on IFN-α/β but highly dependent on IL-12. Vα14i NK T cells contribute to the immune response to MCMV and amplify NK cell–derived IFN-γ. Importantly, mortality is increased in CD1d−/− mice in response to high dose MCMV infection when compared to heterozygote littermate controls. Collectively, these findings illustrate the plasticity of Vα14i NK T cells that act as effector T cells during bacterial infection, but have NK cell–like behavior during the innate immune response to MCMV infection. 相似文献
40.
Reiman EM Webster JA Myers AJ Hardy J Dunckley T Zismann VL Joshipura KD Pearson JV Hu-Lince D Huentelman MJ Craig DW Coon KD Liang WS Herbert RH Beach T Rohrer KC Zhao AS Leung D Bryden L Marlowe L Kaleem M Mastroeni D Grover A Heward CB Ravid R Rogers J Hutton ML Melquist S Petersen RC Alexander GE Caselli RJ Kukull W Papassotiropoulos A Stephan DA 《Neuron》2007,54(5):713-720
The apolipoprotein E (APOE) epsilon4 allele is the best established genetic risk factor for late-onset Alzheimer's disease (LOAD). We conducted genome-wide surveys of 502,627 single-nucleotide polymorphisms (SNPs) to characterize and confirm other LOAD susceptibility genes. In epsilon4 carriers from neuropathologically verified discovery, neuropathologically verified replication, and clinically characterized replication cohorts of 1411 cases and controls, LOAD was associated with six SNPs from the GRB-associated binding protein 2 (GAB2) gene and a common haplotype encompassing the entire GAB2 gene. SNP rs2373115 (p = 9 x 10(-11)) was associated with an odds ratio of 4.06 (confidence interval 2.81-14.69), which interacts with APOE epsilon4 to further modify risk. GAB2 was overexpressed in pathologically vulnerable neurons; the Gab2 protein was detected in neurons, tangle-bearing neurons, and dystrophic neuritis; and interference with GAB2 gene expression increased tau phosphorylation. Our findings suggest that GAB2 modifies LOAD risk in APOE epsilon4 carriers and influences Alzheimer's neuropathology. 相似文献