Activin a plasma levels at birth: an index of fetal hypoxia in preterm newborn

Activin-A is a growth factor involved in cell growth and differentiation, neuronal survival, early embryonic development and erythropoiesis. Hypoxemia is a specific trigger for increasing activin-A in fetal lamb circulation. We tested the hypothesis that fetal hypoxia induces activin-A secretion in preterm newborn infants. Fifty newborn infants with gestational ages ranging from 26 to 36 wk were enrolled in a prospective study performed at the Pediatrics, Obstetrics and Reproductive Medicine Department, University of Siena, Italy. Heparinized blood samples were obtained from the umbilical vein after cord clamping, immediately after delivery. Activin A, hypoxanthine (Hx), xanthine (Xa) plasma levels and absolute nucleated red blood cell (NRBC) count were measured. Activin-A levels (p < 0.0001) and NRBC (p < 0.0001) were significantly higher in hypoxic than in non hypoxic preterm newborns. Cord activin A levels were significantly related with Hx (taua=0.64, taub=0.64, p < 0.0001) and Xa (taua=0.56, taub=0.57, p < 0.0001) levels, NRBC ((taua=-0.45, taub=-0.46, p < 0.0001) count; pH (taua=-0.47, taub=-0.48, p < 0.0001) and base deficit (taua=-0.36, taub=0.-0.36, p = 0.0002). Preterm newborns with signs of perinatal hypoxia at birth have increased activin-A levels, suggesting that activin-A may reflect indirectly intrauterine hypoxia.     

大学生饮酒模式调查分析

目的分析影响大学生饮酒模式的因素,针对饮酒教育及酒精政策提出建议。方法采用整群抽样方法,选择来自北京和郑州的530名大学生完成有效问卷调查。采用 Epidata 录入数据,SAS 12.0和 R 2.7.2进行数据描述和分析。结果74.5%的大学生在过去1年内饮过酒,啤酒是饮酒者的主要选择（85.9%）,餐馆和家里是饮酒比较频繁的场所,饮用酒多来自同学/朋友及家庭成员提供,25.3%饮酒者并无特别原因饮酒,各有约1/5的饮酒者是出于社交目的或喜欢饮酒的感觉。认为“饮酒有助于社交暠或“饮酒促进交流暠者、父母及同学/朋友饮酒者、来自农村地区或小城镇者及吸烟者更容易发生饮酒行为（均 P 〈0.05）,男生大学生、规律饮酒者更容易遭遇强迫劝酒场面、更易发生醉酒（均 P 〈0.05）。超过一半饮酒者出现酒后脸红、肌肉软弱无力等生理反应,饮酒对被调查大学生产生的社会心理影响依次是记忆丧失（23.9%）、宿醉（14.6%）、做了后悔的事（低于10%）等。结论目前大学生仍保持着一种低风险饮酒模式。大学生饮酒教育应提供关于饮酒利弊的科学信息,使其对饮酒保持一种现实的期望。应制定针对性酒精政策和教育鼓励和支持低风险且满足社交功能的饮酒模式,控制高风险饮酒模式。     

Estimates of the US health impact of influenza.

OBJECTIVES. Data from the Tecumseh Community Health Study were used to estimate excess morbidity owing to influenza, and results were compared with estimates made previously using different methodology for an Institute of Medicine report. METHODS. Study participants from Tecumseh, Michigan, were classified as infected or noninfected based on laboratory results. The excess numbers of respiratory illnesses, respiratory illness days, and bed and restricted activity days experienced by the infected compared with the noninfected were estimated. RESULTS. The number of excess influenza-related respiratory illnesses was lower than that estimated in the Institute of Medicine report, in which all illnesses of certain characteristics occurring during an influenza season were attributed to influenza. It is now estimated that the US population under 20 years of age experiences a yearly average of 13.8 to 16.0 million influenza-related excess respiratory illnesses; for older individuals, the yearly estimate is 4.1 to 4.4 million excess illnesses. CONCLUSIONS. For public health purposes, estimates of excess morbidity as well as of total morbidity associated with influenza should be used in setting health priorities.     

Containing pandemic influenza with antiviral agents

For the first wave of pandemic influenza or a bioterrorist influenza attack, antiviral agents would be one of the few options to contain the epidemic in the United States until adequate supplies of vaccine were available. The authors use stochastic epidemic simulations to investigate the effectiveness of targeted antiviral prophylaxis to contain influenza. In this strategy, close contacts of suspected index influenza cases take antiviral agents prophylactically. The authors compare targeted antiviral prophylaxis with vaccination strategies. They model an influenza pandemic or bioterrorist attack for an agent similar to influenza A virus (H2N2) that caused the Asian influenza pandemic of 1957-1958. In the absence of intervention, the model predicts an influenza illness attack rate of 33% of the population (95% confidence interval (CI): 30, 37) and an influenza death rate of 0.58 deaths/1,000 persons (95% Cl: 0.4, 0.8). With the use of targeted antiviral prophylaxis, if 80% of the exposed persons maintained prophylaxis for up to 8 weeks, the epidemic would be contained, and the model predicts a reduction to an illness attack rate of 2% (95% Cl: 0.2, 16) and a death rate of 0.04 deaths/1,000 persons (95% CI: 0.0003, 0.25). Such antiviral prophylaxis is nearly as effective as vaccinating 80% of the population. Vaccinating 80% of the children aged less than 19 years is almost as effective as vaccinating 80% of the population. Targeted antiviral prophylaxis has potential as an effective measure for containing influenza until adequate quantities of vaccine are available.     

基于雌激素浅谈逆针灸预防围绝经期女性高血压病的可行性

女性进入围绝经期后,随着雌激素分泌水平的下降,高血压病的患病率逐年升高。鉴于其不可治愈性,对"高血压前期"给予早期有效的干预,控制高血压病的发生发展,是当前预防围绝经期女性高血压病的有效措施。然而指南指出激素替代疗法和雌激素受体调节剂均不应用于围绝经期女性心血管疾病的预防,针灸作为一种既能同时调节血压和雌激素,又没有明显副作用的治疗方式,给围绝经期女性高血压病的预防带来了新的希望。文章通过探讨针灸、雌激素和高血压病三者的关系,阐释逆针灸预防围绝经期女性高血压病的可行性,为临床诊治提供参考。     

Semi-parametric models for mismeasured exposure information in vaccine trials

Exposure to infection information is important for estimating vaccine efficacy, but it is difficult to collect and inherently prone to missingness and mismeasurement. It is, therefore, generally not feasible to collect good exposure information on all participants in a large vaccine trial. We discuss study designs that collect detailed exposure information for only a small subset of trial participants, while collecting crude exposure information on all participants, and treat estimation of vaccine efficacy in the missing data/measurement error framework. We demonstrate with the example of an HIV vaccine trial the improvements in bias and efficiency when we combine the different levels of exposure information to estimate vaccine efficacy for reducing both susceptibility and infectiousness. We compare the performance of recently developed semi-parametric missing data methods of Pepe and Fleming and Carroll and Wand, Robins, Hsieh and Newey, and Reilly and Pepe. © 1998 John Wiley & Sons, Ltd.     

Subtype-specific transmission probabilities for human immunodeficiency virus type 1 among injecting drug users in Bangkok, Thailand.

The Bangkok (Thailand) Metropolitan Administration cohort of injecting drug users (IDUs) consisted of 1,209 IDUs initially seronegative for human immunodeficiency virus (HIV) who were followed from 1995 to 1998 at 15 Administration drug treatment clinics. At enrollment and approximately every 4 months thereafter, participants were assessed for HIV seropositivity. As of December 1998, there were 133 HIV type 1 seroconversions and approximately 2,300 person-years of follow-up. Of the 133 observed seroconversions, specimens from 126 persons were available for subtyping (27 subtype B, 99 subtype E). In this analysis, the authors assessed differences in subtype-specific transmission while controlling for important risk factors. The methodology used accounts for left truncation, interval censoring, and competing risks as well as for time-varying covariates such as each IDU's history of reported frequency of injection and of incarceration. Using plausible epidemiologic assumptions and controlling for behavioral risks, the authors found that a significantly higher transmission probability was associated with subtype E compared with subtype B in this population. Since many epidemiologic, virologic, and host factors can influence HIV transmission, it was difficult to conclude whether these differences in transmission probabilities were due to biologic properties associated with subtype.     

Direct and indirect effects in vaccine efficacy and effectiveness

In 1915, Greenwood and Yule noted that for valid vaccine efficacy studies, exposure to infection in the vaccinated and the unvaccinated must be equal (Proc R Soc Med 1915;8(part 2):113-94). The direct effect of a vaccine, however, needs to be defined by the protection it confers given a specific amount of exposure to infection, not just a comparable exposure. In this paper, two classes of parameters are distinguished along lines differing from the conventional distinction between efficacy and effectiveness. Efficacy parameters attempt to control for exposure to infection and represent direct effects on individuals. Direct effectiveness parameters represent a mixture of direct effects on individuals and indirect effects in the population.     

Non protein bound iron concentrations in amniotic fluid

OBJECTIVES: To investigate whether amniotic fluid concentrations of non protein bound iron (NPBI) vary with growth in healthy fetuses and also offer a reference curve in the second trimester of pregnancy. DESIGN AND METHODS: Amniotic fluid concentrations of NPBI were measured by HPLC in 118 women with physiological singleton pregnancies, who underwent amniocentesis for fetal karyotype between weeks 15 and 18 of gestation. RESULTS: NPBI increased progressively from weeks 14--15 to weeks 15--16, peaking at 17--18 weeks of gestation. NPBI values regressed positively with gestational age (GA). Multiple linear regression analysis between NPBI, as dependent variable, and various fetal parameters, as independent variables, showed a statistically significant regression coefficient with GA, bi-parietal diameter and transverse cerebellar diameter. CONCLUSIONS: The present data constitutes the first quantification of NPBI concentrations in amniotic fluid under physiological conditions. Correlations with GA and ultrasound fetal biometry suggest that NPBI may play a role in fetal growth.     

A study of adaptive responses in cell signaling in migraine and cluster headache: correlations between headache type and changes in gene expression

The project was an investigation into whether changes in the expression of G-proteins underlie altered cell signaling in migraine and cluster headache. The basis for this assumption is that altered physiological responses are seen in migraineurs and that differences in cell signaling are detected biochemically in various cell types isolated from peripheral blood. Levels of three G-protein mRNAs—Gsα, Giα, and Gqα were quantified in lymphocytes from clinically well-defined migraine and cluster headache patients and correlated with headache type and influence of drug treatment. Giα mRNA was reduced by 50% in all migraine patients compared with control subjects; similarly in patients with or without aura, in patients with a migraine headache at the time of sampling, and patients in a quiescent state. No reduction in the levels of Gsα or Gqα mRNA were seen in migraine patients. A smaller reduction was seen in cluster headache patients, most marked in those without medication. Levels of Gsα. mRNA were significantly reduced in cluster headache patients compared with migraine patients. The marked down-regulation of Giα mRNA in migraine, whether quiescent or acute, indicates either an adaptive response to headache in this group of patients or that low levels of Giα mRNA make individuals more susceptible to migraine.