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It is hypothesized from within an evolutionary framework that females should be less invested in peer relations than males. Investment was operationalized as enjoyment in Study 1 and as preference for interaction in Study 2. In the first study, four- and six-year-old children’s enjoyment of peer interaction was observed in 26 groups of same-sex peers. Girls were rated as enjoying their interactions significantly less than boys. In the second study, six- and nine-year-old children were interviewed about the individuals with whom they spend time in their homes and neighborhoods and about the individuals who participate in their favorite activities. The proportion of individuals named by children who were peers was significantly lower for girls than boys both in children’s neighborhoods and in children’s favorite activities. Results strongly support the hypothesis that females and males have evolved differential preferences for interaction with peers. 相似文献
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《Mutation Research/Genetic Toxicology》1983,116(3-4):323-331
Perchloroethylene (PCE) was tested in a diploid strain (D7) of the yeast Saccharomyces cerevisiae in suspension tests with and without a mammalian microsomal activation system (S9) and ‘in vivo’ by the intrasanguineous host-mediated assay. In addition, enzyme alteration studies were performed in mice non-pretreated or pretreated with phenobarbital + β-naphthoflavone. PCE did not induce any genetic effect either ‘in vitro’ or ‘in vivo’. In the suspension test, PCE was more toxic without metabolic activation and less toxic with mammalian microsomal activation. The enzymatic determinations showed an increase of the aminopyrine demethylase activity and of the level of cytochrome P-450. 相似文献
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Yoshiaki Sumiyoshi Masahiko Kikuchi Morishige Takeshita Kohiti Ohshima Yuhiti Masuda 《Virchows Archiv. B, Cell pathology including molecular pathology》1992,61(1):201-207
In Japan, histiocytic necrotizing lymphadenitis (Kikuchi’s disease) is a relatively common reactive lesion affecting lymph
nodes, but the histogenesis and pathogenesis of the disease have not been clarified. Alpha-interferon has a role in the body’s
defense against, viral infections. Using a polyclonal antibody to human alpha-interferon, we found numerous cells, mainly
histiocytes, containing alpha-interferon in affected foci in the lymph nodes from 24 patients with Kikuchi’s disease. Tubuloreticular
structures, thought by some authors to be associated with the production of interferon, were detected by electron microscopy
in histiocytes, activated lymphocytes and vascular endothelial cells in the affected foci. These results suggested that the
formation of tubuloreticular structures is a secondary phenomenon following stimulation by alpha-interferon. Further, the
activity of 2′–5′ oligoadenylate synthetase, which is induced by alpha-interferon and enhanced during the early or active
stage of viral infection, showed increased levels of activity in the active stage of Kikuchi’s disease and decreased to normal
levels in the convalescent stage 2 weeks later. These results suggested the possibility of a viral etiology for Kikuchi’s
disease. 相似文献
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Aims
This study aimed to document and compare the nature of clinical pharmacists’ interventions made in different practice settings within a children’s hospital.Methods
The primary investigator observed and documented all clinical interventions performed by clinical pharmacists for between 35–37 days on each of the five study wards from the three practice settings, namely general medical, general surgical and hematology-oncology. The rates, types and significance of the pharmacists’ interventions in the different settings were compared.Results
A total of 982 interventions were documented, related to the 16,700 medication orders reviewed on the five wards in the three practice settings over the duration of the study. Taking medication histories and/or patient counselling were the most common pharmacists’ interventions in the general settings; constituting more than half of all interventions. On the Hematology-Oncology Ward the pattern was different with drug therapy changes being the most common interventions (n = 73/195, 37.4% of all interventions). Active interventions (pharmacists’ activities leading to a change in drug therapy) constituted less than a quarter of all interventions on the general medical and surgical wards compared to nearly half on the specialty Hematology-Oncology Ward. The majority (n = 37/42, 88.1%) of a random sample of the active interventions reviewed were rated as clinically significant. Dose adjustment was the most frequent active interventions in the general settings, whilst drug addition constituted the most common active interventions on the Hematology-Oncology Ward. The degree of acceptance of pharmacists’ active interventions by prescribers was high (n = 223/244, 91.4%).Conclusions
The rate of pharmacists’ active interventions differed across different practice settings, being most frequent in the specialty hematology-oncology setting. The nature and type of the interventions documented in the hematology-oncology were also different compared to those in the general medical and surgical settings. 相似文献10.
David E. Kime 《Reviews in Fish Biology and Fisheries》1993,3(2):160-180
Summary The nature of the steroids secreted by gonads of fish differs significantly from those of the mammals. The classical teleost steroids, oestradiol, testosterone, 11-ketotestosterone and 17,20P, have been measured in a wide variety of teleosts but do not always reflect biological activities. There is increasing evidence that teleost gonads may produce a number of non-classical steroids which may play an important role in their reproductive biology. Such products include metabolites reduced at C5 to 5 or 5, at C3 to 3 or 3, or hydroxylated at 6-, 7-, or 21. Conjugation, as either glucuronides or sulphates, may contribute either to localization of action within the gonad or to production of pheromones during the immediate pre-spawning period. Although it is often possible only to measure the steroids for which assays are readily available, it is important to recognize that there may be production of steroids that are not detected by such assays, but which nevertheless play a major role in reproductive activity. In evolutionary terms, the teleost hydroxylases probably originated in the very early fishes and show parallels with their analogues in amphibians and mammals. Gene sequencing may reveal a possible common ancestor for all vertebrate 6, 7 and 11-hydroxylases. 相似文献
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Chasing genes in Alzheimer’s and Parkinson’s disease 总被引:4,自引:0,他引:4
Alzheimers disease (AD), the most common type of dementia, and Parkinsons disease (PD), the most common movement disorder, are both neurodegenerative adult-onset diseases characterized by the progressive loss of specific neuronal populations and the accumulation of intraneuronal inclusions. The search for genetic and environmental factors that determine the fate of neurons during the ageing process has been a widespread approach in the battle against neurodegenerative disorders. Genetic studies of AD and PD initially focused on the search for genes involved in the aetiological mechanisms of monogenic forms of these diseases. They later expanded to study hundreds of patients, affected relative-pairs and population-based studies, sometimes performed on special isolated populations. A growing number of genes (and pathogenic mutations) is being identified that cause or increase susceptibility to AD and PD. This review discusses the way in which strategies of gene hunting have evolved during the last few years and the significance of finding genes such as the presenilins, -synuclein, parkin and DJ-1. In addition, we discuss possible links between these two neurodegenerative disorders. The clinical, pathological and genetic presentation of AD and PD suggests the involvement of a few overlapping interrelated pathways. Their imbricate features point to a spectrum of neurodegeneration (tauopathies, synucleinopathies, amyloidopathies) that need further intense investigation to find the missing links. 相似文献
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Monique Borgerhoff Mulder 《Human nature (Hawthorne, N.Y.)》1992,3(1):45-70
Both behavioral ecological and social anthropological analyses of polygynous marriage tend to emphasize the importance of competition among men in acquisition of mates, whereas the strategic options to women both prior to and after the establishment of a marriage have been neglected. Focusing on African marriage systems that are in some senses analogous to resource-defense polygyny, I first review the evidence of reproductive costs of polygyny to women. Then I discuss why the conflict of interests between men and women over mate number is often likely to be settled in favor of men. Using East African ethnographic data I examine the strategic responses of women and their families to polygynous marriage, focusing on four topics: mate choice (Kipsigis), attitudes toward incoming wives (Kipsigis), labor allocation and cooperation (comparative data, Kipsigis), and use of parental wealth (Datoga). The results of these quantitative analyses suggest that through a combination of judicious marriage choice and strategic responses within marriage, polygyny need not be costly to women in resource-defense polygynous systems. The conclusion is that a hierarchy of questions need to be addressed in the analysis of any polygynous marriage system. 相似文献
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Olivier Rieppel 《Biology & philosophy》2009,24(5):607-622
Taking its clues from Popperian philosophy of science, cladistics adopted a number of assumptions of the empiricist tradition.
These include the identification of a dichotomy between observation reports and theoretical statements and its subsequent
abandonment on the basis of the insight that all observation reports are theory-laden. The neglect of the ‘context of discovery’,
which is the step of theory (hypothesis) generation. The emphasis on coherentism in the ‘context of justification’, which
is the step of evaluation of the relative merits of alternative theories. The appeal to a total evidence approach in phylogenetic
inference. And finally, a silence about causation, which results in an instrumentalist approach to phylogeny reconstruction.
This paper explores how these empiricist assumptions are embedded in phylogenetic systematics, and why these assumptions are
problematic for cladists (or any taxonomists). 相似文献
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Zhu X Lee HG Casadesus G Avila J Drew K Perry G Smith MA 《Molecular neurobiology》2005,31(1-3):205-217
Oxidative stress is a striking feature of susceptible neurons in the Alzheimer’s disease brain. Importantly, because oxidative
stress is an early event in Alzheimer’s disease, proximal to the development of hallmark pathologies, it likely plays an important
role in the pathogenesis of the disease. Investigations into the cause of such oxidative stress show that interactions between
abnormal mitochondria and disturbed metal metabolism are, at least in part, responsible for cytoplasmic oxidative damage observed
in these susceptible neurons, which could ultimately lead to their demise. Oxidative stress not only temporally precedes the
pathological lesions of the disease but could also contribute to their formation, which, in turn, could provide some protective
mechanism to reduce oxidative stress and ensure that neurons do not rapidly succumb to oxidative insults. In this review,
we present the evidence for oxidative stress in Alzheimer’s disease and its likely sources and consequence in relation to
other pathological changes. 相似文献
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Neurochemical Research - Parkinson’s disease (PD), the main risk factor for which is age, is one of the most common neurodegenerative diseases and imposes a substantial burden on affected... 相似文献
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Oxidative stress affecting the thyroxin biosynthesis might explain the proneness of patients with Down's syndrome (DS) (trisomia 21) to develop hypothyroidism. Thyroideal cells are exposed to endogenous H2O2 that acts as a cofactor for the iodination of thyroxin precursors. The gland has high levels of selenium-containing proteins, including peroxide-detoxicating enzyme proteins. The object of the present study was to explore the hypothesis of a role of an imbalance between toxic oxygen production and protective metalloenzymes during the development of thyroid hypofunction in DS patients. We analyzed serum levels of thyroid hormones and trace metals in 38 institutionalized adults with DS, using mentally retarded subjects matched for age, sex, and behavioral function as controls. The DS patients had significantly lower mean values of free thyroxin (fT4) and increased TSH (thyroid stimulating hormone), as compared to the controls. They had lower serum selenium than the controls. A positive correlation was observed between serum concentrations of fT4 and selenium in the DS patients (r = 0.393, p < 0.05). No significant differences were found between the fT4 or the TSH concentrations in the patients with and without circulating antithyroid autoantibodies. Our results support the suggestion that thyroid hypofunction in patients with Down's syndrome in some way is linked to the low serum levels of selenium found in these patients. It is suggested that selenium-containing proteins are involved in thyroid hormonal synthesis, by protecting biosynthetic processes against the toxicity of free oxygen radicals. 相似文献
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DNAs and proteins are major classes of biomolecules that differ in many aspects. However, a considerable number of their members also share a common architectural feature that enables the assembly of multi-protein complexes and thereby permits the effective processing of signals: loop structures of substantial sizes. Here we briefly review a few representative examples and suggest a functional classification of different types of loop structures. In proteins, these loops occur in protein regions classified as intrinsically disordered. Studying such loops, their binders and their interactions with other loops should reveal much about cellular information computation and signaling network architectures. It is also expected to provide critical information for synthetic biologists and bioengineers. 相似文献
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TREM2 in Alzheimer’s disease 总被引:1,自引:0,他引:1
Recent works have demonstrated a rare functional variant (R47H) in triggering receptor expressed on myeloid cells (TREM) 2 gene, encoding TREM2 protein, increase susceptibility to late-onset Alzheimer’s disease (AD), with an odds ratio similar to that of the apolipoprotein E ε4 allele. The reduced function of TREM2 was speculated to be the main cause in the pathogenic effects of this risk variant, and TREM2 is highly expressed in white matter, as well as in the hippocampus and neocortex, which is partly consistent with the pathological features reported in AD brain, indicating the possible involvement of TREM2 in AD pathogenesis. Emerging evidence has demonstrated that TREM2 could suppress inflammatory response by repression of microglia-mediated cytokine production and secretion, which may prevent inflammation-induced bystander damage of neurons. TREM2 also participates in the regulation of phagocytic pathways that are responsible for the removal of neuronal debris. In this article, we review the recent epidemiological findings of TREM2 that related with late-onset AD and speculate the possible roles of TREM2 in progression of this disease. Based on the potential protective actions of TREM2 in AD pathogenesis, targeting TREM2 might provide new opportunities for AD treatment. 相似文献