In vitro H-serotonin (5-HT) synthesis and release in BALBc and C57BL mice. II. Cell body areas

"In vitro" 3H-5-HT and 3H-5-HIAA, newly synthesized from 3H-TRP, are measured in the brainstem, the anterior raphe nuclei and the locus coeruleus of C57BL and BALBc mice. As found for the caudate nucleus and the hippocampus, higher synthesis and release are determined in C57BL than in BALBc, for the locus coeruleus and more globally, for the brainstem. But these differences disappear when the study is carried on the raphe dorsalis and the raphe centralis nuclei. Therefore the serotonergic activity could be independently regulated at the level of cell bodies and at those of terminals. However, the 5-HT metabolism of NRD of BALBc mice could be submitted to a specific autoinhibition which could explain a lower 5-HT synthesis and release at the corresponding terminal level, compared to C57BL.     

Cardiorespiratory and thermal effects of wearing gas protective clothing

Summary Six healthy men aged 25 to 37 walked on a treadmill at work levels of 21 and 41% of their for 25 to 30 min wearing gas protective clothing (GPC) consisting of an impermeable suit with a self-contained breathing apparatus (total weight 25 kg) or shorts (control tests, CT) in a temperate environment (t _a 24.3°C ± 1.0°C, rh 30–50%). When the GPC was worn at 21 and 41% , the most prominent increases, compared with the CT, were noted in the heart rate ( ± SE, 120 ± 5 vs 76 ± 3 beats min^–1 and 171 ± 5 vs 103 ± 3 beats min^–1), mean skin temperature (36.1 ± 0.2 vs 31.3° C ± 0.1°C and 36.9 ± 0.3 vs 30.9°C ± 0.4°C) and sweat rate (473 ± 51 vs 70 ± 23 g m^–2 h^–1 and 766 ± 81 vs 135 ± 18 g m^–2 h^–1) indicating a high cardiovascular and thermoregulatory strain, which was not decreased by ventilating the suit with an air flow of 281 min^–1 at 41% . The ventilation, oxygen consumption and production of carbon dioxide increased in relation to the extra weight of the GPC, partly dependent on the dynamic work level. It was concluded that the increase in the physiological load caused by the GPC was so high that the work-rest regimens, workers' level of physical fitness, cardiovascular health and heat tolerance should be considered whenever gas protective clothing is used.     

HIV-1 CRF55_01B毒株流行特征的研究进展

CRF55_01B是我国报道的HIV-1主要流行毒株之一,具有较为独特的流行病学和基因进化特征。近几年HIV-1分子流行病学监测发现CRF55_01B已经成为我国第五个主要流行HIV-1毒株。本研究从他的发现起源、流行情况、致病性和耐药性及参与的重组等方面进行综述,并讨论了与其流行密切相关的社会和生物学因素。     

蠕变局部损伤开裂的有限元模型

建立了蠕变局部损伤法模型,并给出单元进入损伤态的判据和失效的临界拉伸应变条件,局部蠕变损伤理论的实质就是试样是多种不同蠕变性能材料的统一,并由蠕变应力再分布得到证实,应用有限元对双缺口圆试样作了蠕变局部损伤分析,启裂时间和断裂蠕变应变值均与实验结果相吻合。     

Assessment of Informal Caregiver Assistance and Strain With Total Hip and Knee Arthroplasty

BackgroundThe purpose of our study is to assess which patient-related and caregiver-related factors are predictive of caregiver strain and assistance when caring for total hip and knee arthroplasty (THA and TKA) patients within 2 weeks after surgery.MethodsWe conducted a prospective study of caregivers of participants enrolled in 2 randomized trials. Caregivers provided demographics and completed the Caregiver Strain Index and Caregiver Assistance Scale pre-surgery and post-surgery. We performed backwards stepwise regression with mixed-effects negative binomial models to investigate predictors of caregiver strain and assistance for THA and TKA caregivers.ResultsThree hundred six caregiver/patient pairs were included. Our models of caregiver strain found Caregiver Assistance Scale scores and patient age to be predictive for all caregivers. We also found caregiver gender and smoking status to be predictive for THA caregivers and caregiver age to be predictive for TKA caregivers. Our models of assistance provided by caregivers found time (post-surgery vs pre-surgery) was predictive for all caregivers. We also found patient body mass index, and patient and caregiver gender to be predictive for THA caregivers, and patient and caregiver employment status and caregiver education level to be predictive for TKA caregivers.ConclusionOur study identifies patient-related and caregiver-related factors which are associated with caregiver strain and assistance when caring for arthroplasty patients. As this is the first study to assess assistance provided by caregivers, it is important for future research to validate our results and to further explore whether patient-reported outcomes may also be related to assistance and strain.     

Exposure to psychosocial work strain and changes in smoking behavior during pregnancy – a longitudinal study within the Danish National Birth Cohort

Objective:Knowledge of the relationship between psychosocial strain in the work environment and smoking during pregnancy is scarce. This study aimed to examine the association between psychosocial job strain and change in smoking behavior during pregnancy.Methods:The cohort included 65 645 pregnancies from the Danish National Birth Cohort (1996–2002), where pregnant women were interviewed on job factors and lifestyle during the first and third trimesters. Smoking was categorized into non-, non-daily, and daily smoking at each interview. Psychosocial job strain was categorized into four groups based on the concept of Karasek’s demand–control model: low strain (reference), passive, active and high strain. Associations between psychosocial strain and change in smoking status between the first and second interviews were analyzed by multinomial logistic regression, separately for each smoking category at first interview.Results:Non-smoking women exposed to high strain work were more likely to become daily smokers [adjusted odds ratio (OR_adj) 1.41, (95% confidence interval (CI) 1.08–1.83)] compared to non-smoking women exposed to low strain work. Non-smoking women exposed to passive work were more likely to become both non-daily and daily smokers [OR_adj 1.59 (95% CI 1.21–2.08) and OR_adj 1.32 (95% CI 1.03–1.70), respectively]. Daily smoking women exposed to high strain work were less likely to decrease their smoking [OR_adj 0.57 (95% CI 0.32–0.99)] compared to daily smoking women exposed to low strain work.Conclusions:Psychosocial strain influenced the women’s smoking behavior during pregnancy, especially in job types with low control.     

抗大肠杆菌耐热性肠毒素ST1 McAb杂交瘤细胞系的建立及应用

目的 耐热性肠毒素ST1单克隆抗体制备及在感染性腹泻诊断中的应用。方法 应用基因工程菌株分泌的肠毒素制备ST1包涵体，免疫Balb／c小鼠，成功制备了3株特异性抗ST1的单克隆抗体细胞株，用其中1株McAb建立了检测ST1的双单克隆抗体夹心ELISA法。结果 检测52株从临床腹泻病人粪便中分离的大肠杆菌，检出ST1阳性率为26．92％，与ST1检测的经典方法乳鼠灌胃法符合率为96．15％。结论 该方法是一种简捷、灵敏和特异的检测方法，具有实际应用价值。     

Tensile properties of fresh human calcaneal (Achilles) tendons

The purpose of this study was to measure the tensile properties of fresh human calcaneal (Achilles) tendons. Twenty fresh cadaveric (age range = 57-93 years) bone-Achilles tendon complexes were harvested within 24 hr postmortem. The calcaneus together with 15 cm of the Achilles tendon extending proximally from the insertion on the calcaneus was clamped and biomechanically tested. Each tendon was firmly fixed in clamps in an MTS Systems Corporation MTS testing machine and tension was applied at a displacement rate of 8 cm per minute until the tendon failed. The tensile force and tensile strain (as measured using an extensometer) were recorded and plotted using onboard software. The narrow age range of our donors prevented any meaningful correlation between age and tensile properties; however, the results showed that: 1) the average ultimate tensile strength (UTS) of the human Achilles tendon was 1189 N (range = 360-1,965), 2) there was a correlation between left and right legs for UTS, 3) there was a correlation between left and right legs in regard to cross sectional area, and 4) there was no correlation between UTS and cross-sectional area.     

Helicase Hmi1 stimulates the synthesis of concatemeric mitochondrial DNA molecules in yeast Saccharomyces cerevisiae

Hmi1p is a helicase in the yeast Saccharomyces cerevisiae required for maintenance of the wild-type mitochondrial genome. Disruption of the HMI1 ORF generates ^– and ⁰ cells. Here we demonstrate that, in ^– yeast strains, Hmi1p stimulates the synthesis of long concatemeric mitochondrial DNA molecules associated with a reduction in the number of nucleoids used for mitochondrial DNA packaging. Surprisingly, the ATPase negative mutants of Hmi1p can also stimulate the synthesis of long concatemeric ^– mitochondrial DNA molecules and support the maintenance of the wild-type mitochondrial genome, albeit with reduced efficiency. We show that, in the mutant hmi1–5 background, the wild-type mitochondrial DNA is fragmented; and we propose that, in hmi1 yeast cells, the loss of the wild-type mitochondrial genome is caused by this fragmentation of the mitochondrial DNA.