Modulation of catecholamine release and cortisol secretion by social interactions in the rainbow trout,Oncorhynchus mykiss

The objective of the present study was to investigate the effect of social status on the ability of rainbow trout to secrete the stress hormones, cortisol, and catecholamines. Rainbow trout were confined in pairs for six days to permit the formation of dominance hierarchies. An in situ saline-perfused posterior cardinal vein (PCV) preparation was then used to assess cortisol secretion or release of the catecholamine hormones, adrenaline and noradrenaline, in response to the inclusion of appropriate secretagogues in the perfusate. Fish identified as subordinate on the basis of their behaviour showed a characteristic elevation of circulating plasma cortisol concentrations when compared with dominant fish. When the interrenal cells were stimulated in situ with adrenocorticotropic hormone, subordinate fish displayed a significantly lower rate of cortisol secretion than dominant fish. However, social status had no significant effect on either adrenaline or noradrenaline secretion rates upon stimulation of the chromaffin cells in situ with acetylcholine. These results suggest that the chronic elevation of plasma cortisol associated with subordinate social status in rainbow trout reduces the sensitivity of the cortisol-secreting interrenal cells, presumably through negative feedback mechanisms.     

Perceptions of sexuality as related to sexual functioning and sexual risk in women with different types of childhood abuse histories

Perceptions of one's sexuality, self-reported sexual functioning, and sexual risk were examined in a community sample of 148 women with histories of either childhood sexual abuse (n = 26), both childhood sexual and physical abuse (n = 44), and neither form of abuse (n = 78). Controlling for depression and anxiety, the groups did not differ on sexual desire, arousal/orgasm, sexual pain, or masturbation. Women with abuse histories reported more negative affect during sexual arousal and reported more lifetime vaginal intercourse partners than nonabused women. In addition, the abuse samples reported more negative perceptions of their sexuality in their worst psychological states using the Structural Analysis of Social Behavior (SASB) method than did women with no abuse history. An interpersonal focus and more precise abuse labeling are recommended, potentially revising our assumptions about symptom clusters and treatment.     

盐酸埃他卡林选择性降压作用的研究

目的 :在清醒正常血压犬和“两肾一夹”肾性高血压犬 (RHD)上 ,观察不同剂量盐酸埃他卡林(iptakalimhydrochloride,Ipt)的降压作用特征 ;在清醒正常血压的Wistar大鼠和脑卒中易感型自发性高血压大鼠 (stroke pronespontaneouslyhypertensiverat,SHRsp)上 ,采用无创心功能监测方法 ,观察Ipt对心功能和血流动力学的作用特征 ,以判断其降压作用和对心功能及血流动力学的影响是否具有选择性。方法 :给清醒正常血压犬和RHD口服不同剂量的Ipt,用听诊法测量移于皮鞘内的颈总动脉血压 ,用触诊法测量心率 ,同时记录Ⅱ导联心电图。给清醒正常血压大鼠和SHRsp静脉注射相同剂量的Ipt,采用清醒无创心功能血流动力学实验方法 ,观察Ipt对对心功能和血流动力学的影响。结果 :在RHD模型上 ,单次口服Ipt0 .1 2 5、0 .2 5、0 .5、1 .0mg·kg- 1 后 ,产生剂量依赖性的降压作用 ,0 .5h开始起效 ,2～ 3h达效应峰值 ,其最大降低SBP幅度分别为 1 3、2 3、2 5、3 6mmHg,降压作用维持时间分别为 4、6、6、1 2h。在清醒正常血压犬上 ,单次口服Ipt 0 .8,3 .2 ,1 2 .8mg·kg- 1 ,其中剂量为 0 .8和 3 .2mg·kg- 1 时 ,血压和心率均无明显变化 ,剂量增至 1 2 .8mg·kg- 1 时 ,在给药后 5h之内可以显著降低收缩压和舒张压 ,其最大降低SB     

Preservation of neurological functions by nitric oxide synthase inhibitors following hemorrhagic shock

Excessive production of nitric oxide (NO) as result of inducible nitric oxide synthase (iNOS) induction has been implicated in the pathophysiology of hemorrhagic shock. Our aim was to study the effect of iNOS inhibitors, L-canavanine (50mg/kg) and N(G)-nitro- L-arginine methyl (L-NAME, 10mg/kg) and a resuscitation fluid, lactated Ringer's solution (3 times amount of blood lost), on survivability and neurological functions in rodents subjected to hemorrhagic shock. L-canavanine-treated rats had significantly higher survival rates (75%) compared to L-NAME-treated rats (44%) and lactated Ringer's solution-treated rats (40%), 72 h following hemorrhagic shock. A marked increase in the neurological performance was observed in L-canavanine-treated rats over the three-day period. Histological examinations also showed a reduction of degenerating neurons in L-canavanine-treated rats when compared to L-NAME-, lactated Ringer's solution- or un-treated rats. Mean arterial blood pressure (MABP), nitrate/nitrite level, glutamic oxalacetic transaminase (GOT) level, and blood gases were also significantly improved in L-canavanine-treated rats when compared to those of L-NAME-, lactated Ringer's solution- or un-treated rats. In conclusion, L-canavanine-treated rats were able to improve survivability, attenuate organ damage, and improve neurological outcome when compared to other treatment groups. It is therefore suggest that L-canavanine may be beneficial as a potentially useful therapeutic agent in treating neurological deficit as a result of hemorrhagic shock.     

Titrating and evaluating multi-drug regimens within subjects

The dosing of combination therapies is commonly undertaken empirically by practising physicians, and a coherent algorithm to approach the problem of combination dosing is currently lacking. Current methods of evaluating multiple drug combinations in clinical trials fail to provide information regarding the location of more effective doses when the combination is not found to differ from the standard, even though the absence of a difference does not necessarily mean the new combination is ineffective. Moreover, in studies where the new combination is found more effective, often a large proportion of the study participants obtain no benefit from the trial. Even with early stopping rules, the time these subjects spend on inferior treatments can have lasting detrimental effects, leading to problems with patient enrolment and adherence to study protocol. This paper describes an evolutionary operation (EVOP) direct-search procedure to titrate combination doses within individual patients. The Nelder-Mead simplex direct-search algorithm is used to titrate combinations of drugs within individual subjects. Desirability functions are utilized to define the main response of interest and additional responses or constraints. Statistical methodology for determining whether the titrated treatment combination has resulted in an improvement in subject response and for evaluating for therapeutic synergism is developed. Inferences can then be made about the efficacy of the combination or about the individual drugs that comprise the combination. The advantages of this approach include affording every patient the potential to benefit from the combination under study and permitting the consideration of multiple endpoints simultaneously.     

Investments in social capital--implications of social interactions for the production of health

This paper develops a theoretical model of the family as producer of health- and social capital. There are both direct and indirect returns on the production and accumulation of health- and social capital. Direct returns (the consumption motives) result since health and social capital both enhance individual welfare per se. Indirect returns (the investment motives) result since health capital increases the amount of productive time, and social capital improves the efficiency of the production technology used for producing health capital. The main prediction of the theoretical model is that the amount of social capital is positively related to the level of health; individuals with high levels of social capital are healthier than individuals with lower levels of social capital, ceteris paribus. An empirical model is estimated, using a set of individual panel data from three different time periods in Sweden. We find that social capital is positively related to the level of health capital, which supports the theoretical model. Further, we find that the level of social capital (1) declines with age, (2) is lower for those married or cohabiting, and (3) is lower for men than for women.     

Mobility limitations 1974-1991: period changes explaining improvement in the population

The proportion of people with mobility limitations (difficulties with running, walking and stairs) decreased between 1968 and 1991 in the Swedish population aged 18-75. The distribution of predictors of late life morbidity, e.g., social class, health behaviour and childhood conditions, also changed during this period. This study explored whether the changes in these predictors over time were related to the decrease in the proportion of the population with mobility limitations. In two nationally representative interview samples (n=4468) from 1974 and 1991 of persons aged 45-71 the odds for limitations were cross-sectionally compared in ordered logistic regression models. In addition, predictors for the mobility outcome in 1974 were collected from an earlier 1968 survey and predictors for the 1991 outcome were collected from 1981. In 1974 the odds for limitations in the population was 50% higher than in 1991. Had the population composition regarding social class and housewives in 1991 been identical to 1974, the odds for limitations would have been similar in 1974 and 1991. Period improvement in social classes with poorer mobility also contributed to the overall period improvement. Health behaviours were examined as possible mediating factors. The increase of physically active people between 1968 and 1974 was related to the period improvement in mobility between 1974 and 1991. Smoking showed an increased association with mobility limitations during the period, indicating that mobility improvement would have been greater if everyone had been a non-smoker. Results indicate how sensitive disability rates may be for cohort or period effects.     

Hip fractures among older people: do marital status and type of residence matter?

This study analysed the extent to which civil status and type of residence affect the risk of elderly people sustaining a hip fracture. The study population consisted of all residents, aged 65 years or older, living in Stockholm County in Sweden between the years 1993 and 1995 (about 250,000 in total). Cases of hip fractures in the County's outpatient register (1993-1995) were linked to national registers, enabling injured people to be attributed a marital status (during year of injury), and also a size of dwelling and form of residential entitlement (in 1990). Gender-specific injury rates for three age groups were computed, as were age-standardized odds ratios (ORs) by gender for each variable of interest. As expected, hip fractures were found to rise with age among both men and women, and the risk of women sustaining such injuries was higher than that of men for all age groups. The proportion of injured men and women was higher among the unmarried than the married, and the majority of the injured were in rented accommodation (in all three age groups). The age-standardized ORs showed that the risk of hip fracture was substantially affected by civil (marital) status, but form of residential entitlement and size of dwelling did not affect the risk to any remarkable extent. The study demonstrates that being unmarried increases the risk of hip fracture among older men and women. This suggests that elderly unpartnered people may have a different daily-life pattern and may be in poorer health, both of which may be associated with a diminished social network.     

Gender differences in street economy and social network correlates of arrest among heroin injectors in Baltimore,Maryland

In a sample of 761 heroin injectors in Baltimore, Maryland, correlates of arrest for drug-related and non-drug-related criminal offenses, by gender, were examined. This investigation examined gender differences in involvement in the drug economy and correlates of arrest. Correlates included roles in the street drug economy, social network attributes, and economic and demographic variables. Gender differences were found. Selling drugs was strongly associated with drug-related arrests for males. Steering (i.e., publicizing drug brands) was highly associated with drug-related arrests for females. Level of heroin addiction was associated with drug-related arrests for males, but not for females. The associations of social network variables with arrests also differed by gender. For females but not males, a higher number of females in one’s network was associated with a lower frequency of arrests. For males, having at least one heroin injector in the personal network was associated with a decreased frequency of arrest, while for females the direction of the association was reversed. These findings suggest the importance of modeling drug behaviors by gender.     

Use of faith-based social service providers in a representative sample of urban homeless women

There are few quantitative studies on the characteristics of homeless persons who use faith-based social service providers. To help address the lack of information in this area, we analyzed survey data on 974 participants in the University of California at Los Angeles (UCLA) Homeless Women’s Health Study, a representative sample of homeless women at shelters and meal programs in Los Angeles County. The primary objective of this analysis was to estimate the association of religious affiliation, race/ethnicity, income, and other client characteristics with the use of faith-based programs. In interviews at 78 homeless shelters and meal programs, study respondents provided information about their religious affiliation and other social and demographic characteristics. The names of the organizations were examined, and those with names that referenced specific religions or contained words connoting religiosity were designated as “faith based”. At the time they were selected for study participation, 52% of respondents were using the services of faith-based providers. In multivariate logistic regression analysis, lower odds of using these providers were estimated for participants with no religious affiliation (compared with Christian respondents) and for African Americans and Latinas (compared with whites). There is evidence of systematic differences between the clients of faith-based and secular social service providers. The benefits of increased funding through a federal faith-based policy initiative may accure primarily to subgroups of clients already using faith-based programs. Dr. Heslin is Assistant Professor in the Charles R. Drew University of Medicine and Science; Dr. Andersen is Wasserman Professor in the UCLA Department of Health Services; Dr. Gelberg is George F. Kneller Professor in the UCLA Department of Family Medicine and was a Robert Wood Johnson Foundation Generalist Physician Faculty Scholar during this study. The views expressed in this article are those of the authors and should not be attributed to funding agencies or other organizations.