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Paternal behavior is associated with an increase in prolactin levels in fish, birds and mammals, including rodents. The striped mouse (Rhabdomys pumilio) from southern Africa shows highly developed paternal care. We investigated whether striped mouse fathers have higher prolactin levels than nonfathers, and whether there is a relationship between tactile stimulation with pups and prolactin secretion in fathers. We measured serum prolactin in 42 male striped mice assigned to one of four different experimental groups (single males, paired males, fathers housed with mother and pups, and fathers separated from their family by a wire-mesh partition). Our results revealed no increases in prolactin levels in fathers, and fathers with tactile contact with pups did not have higher prolactin levels than the fathers that were prevented from making tactile contact with pups. In contrast, experienced males had higher prolactin levels than inexperienced males. Male striped mice are polygynous in nature, living in groups, with three breeding females, and are permanently associated with pups during the breeding season. In a field study, males had higher prolactin levels during the breeding season than during the nonbreeding season. Thus, prolactin secretion in the polygynous striped mouse might be regulated by environmental stimuli, whereas social stimuli might be important for monogamous species. This is the first study to demonstrate seasonal changes in prolactin levels in a free-living male mammal. 相似文献
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目的 了解上海市居民膳食营养状况及季节特征。方法 分别在2012-2014年间4个不同季节对上海市代表性样本人群进行追踪调查,采用连续3 d 24 h膳食回顾询问法辅以家庭调味品称重法收集食物摄入信息。依据中国食物成分表计算能量及产能营养素摄入。结果 2012-2014年上海市居民全年平均每标准人日粮谷类摄入量191.09 g、蔬菜250.69 g、水果107.23 g、动物性食物223.53 g、乳及乳制品96.39 g、大豆及其制品11.19 g、烹调油36.54 g、烹调盐7.57 g,不同季节食物消费差异有统计学意义(P<0.05)。平均每标准人日能量摄入量2 048.70 kcal、碳水化合物241.04 g、蛋白质82.35 g、脂肪85.99 g,脂肪提供能量百分比37.99%。季节、年龄、地区和收入是膳食结构的影响因素(P<0.05)。结论 上海市居民能量摄入满足需求,脂肪能量摄入比例较高,膳食结构欠合理。烹调油、盐摄入量低于国家大城市平均水平但仍高于推荐量,应继续开展针对性营养干预。膳食摄入存在季节特征,夏季膳食摄入更合理,相关研究需考虑季节因素影响。 相似文献
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Characterization of seasonal variation of Staphylococcus aureus is important in understanding the epidemiology of, and designing preventive strategies against this highly virulent and ever-evolving pathogen. In this review, we summarize the findings of epidemiological studies that have evaluated seasonality in S. aureus colonization and infection. Although most studies published to date are methodologically weak, some seasonal variation in the occurrence of S. aureus infection appears to exist, particularly an association of warm-weather months with S. aureus skin and soft-tissue infections. We highlight the limitations of the published literature, and provide suggestions for future studies on this topic. 相似文献
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《Vaccine》2014,32(52):7148-7153
ObjectivesTo determine if birth month has an effect on the incidence of adverse events following the 2- and 12-month recommended vaccinations.Study designUsing health administrative databases, we conducted a population-based retrospective cohort study and employed a self-controlled case series analysis approach. We included children born in Ontario, Canada between April 1st 2002 and March 31st 2010 who received the diphtheria, tetanus, pertussis, inactivated poliovirus and Haemophilus influenzae type b (DTaP-IPV-Hib) vaccine recommended at 2 months and/or the measles, mumps, and rubella vaccine recommended at 12 months. We calculated the relative incidence (RI) of hospitalizations and emergency room visits within a pre-specified risk period compared to a control period following vaccination. We measured the effect of birth month using relative incidence ratios (RIRs) to compare the RI for infants born in each month to that for the month having the lowest RI.ResultsFor the 2-month vaccination, we observed the lowest and highest RIs for infants born in October and April, respectively. The RIR (95% CI) for April compared to October was 2.06 (1.59–2.67, p < 0.0001), consistent with a strong seasonal effect. For the 12-month vaccination, November births had the lowest RI, whereas August births had the highest. The RIR (95% CI) for August compared to November was 1.52 (1.30–1.77, p < 0.0001).ConclusionsOur findings suggest a seasonal effect on susceptibility to adverse events following vaccination exists. Further study will be important to elucidate potential biological and/or behavioral explanations for the seasonal effect we observed. 相似文献
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BackgroundCystic fibrosis is a degenerative disease characterized by progressive epithelial secretory gland dysfunction associated with repeated respiratory infections. Bacterial infections are very frequent in children with cystic fibrosis, but because rapidMethodsfor screening for the wide variety of potentially involved viruses were unavailable until recently, the frequency of viral presence is unknown. Multiplex PCR enables screening for many viruses involved in respiratory infections.ObjectivesThis study aimed to evaluate the frequency of viruses and bacteria in respiratory specimens from children with cystic fibrosis and to clarify the incidence and characteristics (seasonality and age of patients) of different viruses detected in children with cystic fibrosis.Study designIn this 2-year prospective study, we obtained paired nasopharyngeal-swab and sputum specimens from children with cystic fibrosis during clinical respiratory examinations separated by at least 14 days. We analyzed viruses in nasopharyngeal-swab specimens with multiplex PCR and bacteria in sputum with standard methods.ResultsWe analyzed 368 paired specimens from 33 children. We detected viruses in 154 (41.8%) and bacteria in 132 (35.9%). Bacteria were commoner in spring and summer; viruses were commoner in autumn and winter. In every season, Staphylococcus aureus was the commonest bacteria and rhinovirus was the commonest virus. Nearly all infections with Haemophilus influenzae occurred in autumn and winter.Viruses were more prevalent in children <5 years old, and bacteria were more prevalent in children ≥12 years old.ConclusionsMultiplex PCR screening for respiratory viruses is feasible in children with cystic fibrosis; the clinical implications of screening warrant further study. 相似文献
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This study investigated and reports norovirus diarrhoea, genetic diversity and associated clinical symptoms, HIV status and seasonality in a paediatric population of Tanzania.Stool specimens and demographic/clinical information, were prospectively collected from 705 hospitalised children with diarrhoea (cases) and 561 children without diarrhoea (controls) between 2010 and 2011. Norovirus detection was done by real-time RT-PCR. Genotype was determined using Gel-based and real time RT-PCR methods and sequencing targeting the polymerase and the capsid region respectively. Norovirus was detected in 14.3%, 181/1266 children. The prevalence of norovirus was significantly higher in cases (18.3%, 129/705) than in controls, (9.2%, 52/561), P < 0.05. Except for one child who had double infection with GI and GII all 129 cases had GII. Among controls, 23.1% had GI and 76.9% had GII. Norovirus GII.4 was significantly more prevalent in cases 87.9% than in controls 56.5%. Other genotypes detected in both cases and controls were GII.21, GII.16 and GII.g. The highest numbers of norovirus were detected in April 2011. The number of norovirus detected was significantly higher during the first than second year of life (109/540, 20.2% vs. 20/165, 12.1%). The prevalence of norovirus in HIV-positive and negative children was (21.2%, 7/33) and (10.3%, 40/390, P = 0.05) respectively, regardless of diarrhoea symptoms. No significant difference in gender, parent’s level of education or nutritional status with norovirus infection was observed within cases or controls. This study confirms the significant role of norovirus infection, especially GII.4 in diarrhoeic children who need hospitalisation and adds knowledge on norovirus epidemiology in the African region. 相似文献