Transwell技术模拟人类免疫缺陷病毒感染黏膜及其他屏障系统的应用

近年来,由于Transwell小室能在体外模拟机体许多黏膜及生物屏障系统,如人生殖道黏膜、直肠组织黏膜以及血-脑屏障、血-视网膜屏障等,重现人类免疫缺陷病毒(HIV)感染机体的过程,对HIV感染机体的机制研究极为重要,因而被广泛应用.目前,尚无有效抗HIV疫苗问世,因此开发能阻断HIV性传播的药物是有效途径之一.应用Transwell技术深入研究HIV穿透黏膜及屏障系统感染机体的机制,也能为HIV防治药物的研发寻找新的作用靶点.本文就近年来Transwell技术在HIV感染黏膜及其他屏障系统中的应用作一综述.     

静脉吸毒人群中性工作者对HIV/AIDS传播和流行的影响

本文利用数学模型,研究了静脉吸毒人群中的性工作者通过商业性活动对HIV/AIDS传播和流行的影响.讨论了基本再生数、边界平衡点的稳定性、系统的一致持续性和地方病平衡点的存在性,揭示了性工作者的商业性活动可加强HIV/AIDS的传播和流行.特别地,若无商业性活动且吸毒人群和嫖客人群中均无疾病流行时,商业性活动的存在将会导致两类人群中的疾病均流行起来.     

具水平抑制及母婴垂直传播的分数阶HIV/AIDS传染病模型的稳定性研究

研究了一类具水平抑制参数及母婴垂直传播的分数阶HIV/AIDS传染病模型.在该模型中,考虑易感人群的常数输入和母婴垂直传播的影响,并引入抑制参数,以反映水平方向上预防措施的功效.本文利用分数阶微分方程理论及数值模拟方法,研究了模型平衡点的稳定性,分析了水平控制参数对HIV/AIDS传染的抑制作用及母婴垂直传播对HIV/AIDS传染的影响.     

我国男男性行为人群中人类免疫缺陷病毒感染疫情特点及防治策略

目前我国人类免疫缺陷病毒（HIV）感染疫情总体处于低流行水平,但男男性行为（MSM）人群中HIV感染呈现快速上升趋势,传播亚型呈现出新的特点,疾病进展较快。HIV核酸及抗原抗体检测等手段对早期发现MSM人群中HIV感染者具有重要意义。解析MSM人群艾滋病疾病进展的影响因素,发现新的生物学标记,可为早期评估HIV感染的预后提供创新性手段。早期发现我国MSM人群中HIV感染者和抗病毒治疗等综合干预,对我国艾滋病流行的控制具有重要意义。     

北京地区部分人类免疫缺陷病毒基因型分析

我国于1985年发现第1例ADS患者,据估计到2001年底我国艾滋病病毒(Humanimmunodeficiency viruses,HIV)感染者和患者累计数已达84万人,而且我国艾滋病的传播呈快速增长的态势,2001年报告艾滋病病毒感染数较上年增长了58%.HIV主要通过静脉吸毒、输血或使用血液制品以及不良性行为传播.     

人免疫缺陷病毒母婴传播研究进展

随着抗逆转录病毒药物和抗蛋白酶抑制剂的联合应用,人免疫缺陷病毒(HIV)的垂直传播率可降至2%以下。尽管如此,据估计全世界每天仍有1600名婴儿感染HIV。因此,研究HIV母婴传播中的危险因素和干预措施,仍然是极为重要的防治垂直传播的课题。我们就HIV母婴传播的最新进展做简要综述。     

人免疫缺陷病毒的受体与辅助受体

人免疫缺陷病毒(Human Immunodeficiency Virus, HIV)是引起艾滋病的病原.由于该病的病死率较高,目前尚没有被广泛接受的有效的医治方法,所以世界各国对艾滋病都十分重视.在感染HIV时,HIV首先与靶细胞上的受体(receptor)结合后,才能进入该细胞并在其内繁殖.所以充分地了解HIV的受体及辅助受体(coreceptor),对控制HIV的感染和传播是至关重要的.     

静脉注射吸毒人群HIV／AIDS数学模型分析

建立了四川省西昌市静脉注射吸毒人群HIV／AIDS传播的数学模型,给出了模型的理论分析和数值模拟结果．通过必要的分析,给出了各类平衡点的存在性和稳定性,系统的一致持续生存,以及基本再生数的数学表达式和具体取值．揭示了该静注人群中的HIV／AIDS有进一步蔓延的趋势,但如果采取适当的干预措施,该静注人群中HIV／AIDS流行可得到有效的控制．     

名刊封面

《病毒学》2010.3 HIV的T细胞突触间传播 众所周知,人类缺陷病毒（HIV）是导致艾滋病的元凶,能够感染并杀伤CD4阳性T细胞以达到摧毁人体免疫系统的目的。目前,研究者通过电子断层扫描显微镜及3D重建技术,描述了HIV在T细胞之间的传播过程。     

一类考虑耐药性的HIV/AIDS数学模型

本文构建了一类考虑耐药性的HIV/AIDS数学模型,讨论了基本再生数、无病平衡点的全局稳定性以及地方病平衡点的存在性和全局稳定性.所得结果表明,耐药性的出现会改变基本再生数的取值,从而对HIV/AIDS的传播和流行产生重要影响.     

HIV prevention for indigenous people of the Amazon basin.

This study identifies theoretically-based predictors of condom use in a sample of 251 sexually active adults recruited from Sao Gabriel da Cachoeira and six indigneous communities of the Upper Rio Negro region of Amazonas Brazil. The information-motivation-behavioral skills (IMB) model of AIDS-preventive behavior was used to describe the roles of HIV/AIDS knowledge, experiences with and attitudes toward condom use, peer influences, perceived vulnerability, monogamy and behavioral skills. A predictive path analytic model revealed significant predictors of more condom use including male gender, greater sexual HIV knowledge, positive experiences and attitudes about condom use, multiple partners, and greater behavioral skills. Results suggest that attention to behavioral skills for negotiating safer sex and instruction in the correct use of condoms are important elements in reducing high risk behaviors. Increasing the specific knowledge level of indigenous people regarding the complexities of sexual transmission of HIV is crucial and should be addressed. Heightening individuals' understanding of the limited protection of serial monogamy, and the need to conduct gender-specific training for behavior change to reduce transmission of HIV should be an additional goal of Brazilian health professionals. Obstacles to the implementation of the IMB HIV prevention program in Amazonas are noted and an alternative Brazilian HIV/AIDS prevention program is discussed.     

Correlates of Social Exclusion and Negative Labeling and Devaluation of People Living with HIV/AIDS in Rural Settings: Evidence from a General Household Survey in Zambézia Province,Mozambique

Background

Increased HIV/AIDS knowledge and access to antiretroviral treatment (ART) have been hypothesized to decrease HIV stigma. However, stigma persists as a barrier to HIV services uptake. We studied the relationship between stigma, knowledge and attitudes towards HIV and its treatment, and confidence in the legal system (legal rights certitude).

Methods

We analyzed data from a household survey of 3749 randomly sampled female heads of households in 259 enumeration areas across 14 districts of Zambézia Province, Mozambique. The questionnaire included questions about beliefs, attitudes and behavior towards PLWHA, HIV transmission knowledge, treatment-related beliefs, and legal rights certitude. Factor analysis distinguished two stigma constructs: Negative labeling and devaluation (NLD) and social exclusion (SoE). Multivariable linear regression was used to determine the association between stigma, knowledge of HIV/AIDS, treatment-related beliefs, and legal rights certitude, while controlling for variance in socio-demographics.

Results

A 4-point increase in knowledge about HIV transmission was associated with more than a 3 unit decrease in NLD and SoE stigma scores (p<0.001). Given HIV transmission knowledge, a 25-point increase in legal rights certitude was associated with a 4.62 unit drop in NLD stigma (p<0.001); we did not detect an association between legal rights certitude and SoE stigma. Knowing at least one HIV positive person was associated with lower SoE (−3.17, 95% CI: −5.78, −0.56); no association with NLD (p = 0.1) was detected. ART efficacy belief was associated with higher NLD and lower SoE (2.90 increase and 6.94 decrease, respectively; p≤0.001).

Conclusion

Increasing knowledge about HIV transmission and access to ART are likely to reduce stigma, but neither of the two is a panacea. Raising community awareness of the legal rights of PLWHA might improve the efficacy of stigma reduction efforts. Strategies that focus on specific domains of stigma might be more effective than generic stigma reduction strategies.     

Avian prey-dropping behavior. I. The effects of prey characteristics and prey loss

Numerous species of birds break hard-shelled prey items by droppingthem from a height. This intriguing prey-extraction method providesan excellent opportunity for studying foraging behavior becausea single, easily measurable quantity—height of drop—maybe influenced by a wide variety of identifiable characteristicsof the prey (e.g., breakability, weight) and social environment(e.g., alone or in the presence of kleptoparasites). Using adynamic, state variable modeling approach, this paper presentsthe first theoretical framework for avian prey-dropping systemsthat incorporates the diversity of prey characteristics andsocial situations. The model yielded a series of qualitativepredictions about prey-dropping behavior that can be testedreadily in any prey-dropping system. In particular, the results indicatedthat quantitative and qualitative differences in item breakability andpotential kleptoparasitism should have a significant effecton the height and pattern of prey dropping.     

HIV/AIDS in rural India: context and health care needs

Primary research on HIV/AIDS in India has predominantly focused on known risk groups such as sex workers, STI clinic attendees and long-distance truck drivers, and has largely been undertaken in urban areas. There is evidence of HIV spreading to rural areas but very little is known about the context of the infection or about issues relating to health and social impact on people living with HIV/AIDS. In-depth interviews with nineteen men and women infected with HIV who live in rural areas were used to collect experiences of testing and treatment, the social impacts of living with HIV and differential impacts on women and men. Eight focus group discussions with groups drawn from the general population in the four villages were used to provide an analysis of community level views about HIV/AIDS. While men reported contracting HIV from sex workers in the cities, women considered their husbands to be the source of their infection. Correct knowledge about HIV transmission co-existed with misconceptions. Men and women tested for HIV reported inadequate counselling and sought treatment from traditional healers as well as professionals. Owing to the general pattern of husbands being the first to contract HIV women faced a substantial burden, with few resources remaining for their own or their children's care after meeting the needs of sick husbands. Stigma and social isolation following widowhood were common, with an enforced return to the natal home. Implications for potential educational and service interventions are discussed within the context of gender and social relations.     

HIV Sexual Transmission Is Predominantly Driven by Single Individuals Rather than Discordant Couples: A Model-Based Approach

Understanding the relative contribution to HIV transmission from different social groups is important for public-health policy. Information about the importance of stable serodiscordant couples (when one partner is infected but not the other) relative to contacts outside of stable partnerships in spreading disease can aid in designing and targeting interventions. However, the overall importance of within-couple transmission, and the determinants and correlates of this importance, are not well understood. Here, we explore how mechanistic factors – like partnership dynamics and rates of extra-couple transmission – affect various routes of transmission, using a compartmental model with parameters based on estimates from Sub-Saharan Africa. Under our assumptions, when sampling model parameters within a realistic range, we find that infection of uncoupled individuals is usually the predominant route (median 0.62, 2.5%–97.5% quantiles: 0.26–0.88), while transmission within discordant couples is usually important, but rarely represents the majority of transmissions (median 0.33, 2.5%–97.5% quantiles: 0.10–0.67). We find a strong correlation between long-term HIV prevalence and the contact rate of uncoupled individuals, implying that this rate may be a key driver of HIV prevalence. For a given level of prevalence, we find a negative correlation between the proportion of discordant couples and the within-couple transmission rate, indicating that low discordance in a population may reflect a relatively high rate of within-couple transmission. Transmission within or outside couples and among uncoupled individuals are all likely to be important in sustaining heterosexual HIV transmission in Sub-Saharan Africa. Hence, intervention policies should be broadly targeted when practical.     

Social transmission of maladaptive information in the guppy

Many animals are capable of learning from others, a processreferred to as social learning. There is little doubt that acapacity for social learning is an adaptation and that it typicallyresults in adaptive behavior. What is less clear is whetherthere are circumstances under which social learning can resultin the transmission of outdated, inappropriate, or maladaptiveinformation. Here we report an experimental study that investigatedthe social learning and transmission of maladaptive foraginginformation through small social groups of guppies, Poeciliareticulata. This experiment used a transmission chain designin which fish in small founder groups were trained to take eitheran energetically costly circuitous route to a feeder or a lesscostly short route, with trained founder members gradually replacedby untrained conspecifics. Three days after all the foundershad been removed, the behavioral traditions of groups of untrainedfish were still strongly influenced by their founder's behavior.Moreover, the rate at which untrained subjects that shoaledwith founder conspecifics trained to take the long route learnedto take the short route was significantly slower than for fishforaging alone. The results provide unequivocal evidence thatmaladaptive information can be socially transmitted throughanimal populations and imply that socially learned informationcan inhibit learning of the optimal behavior pattern.     

Beyond Race and Place: Distal Sociological Determinants of HIV Disparities

Informed behavior change as an HIV prevention tool has yielded unequal successes across populations. Despite decades of HIV education, some individuals remain at high risk. The mainstream media often portrays these risk factors as products of race and national borders; however, a rich body of recent literature proposes a host of complex social factors that influence behavior, including, but not limited to: poverty, income inequality, stigmatizing social institutions and health care access. We examined the relationship between numerous social indicators and HIV incidence across eighty large U.S. cities in 1990 and 2000. During this time, major correlating factors included income inequality, poverty, educational attainment, residential segregation and marriage rates. However, these ecological factors were weighted differentially across risk groups (e.g. heterosexual, intravenous drug use, men who have sex with men (MSM)). Heterosexual risk rose significantly with poor economic indicators, while MSM risk depended more heavily on anti-homosexual stigma (as measured by same-sex marriage laws). HIV incidence among black individuals correlated significantly with numerous economic factors but also with segregation and imbalances in the male:female ratio (often an effect of mass incarceration). Our results support an overall model of HIV ecology where poverty, income inequality and social inequality (in the form of institutionalized racism and anti-homosexual stigma) have over time developed into synergistic drivers of disease transmission in the U.S., inhibiting information-based prevention efforts. The relative weights of these distal factors vary over time and by HIV risk group. Our testable model may be more generally applicable within the U.S. and beyond.     

Ex vivo modeling of oral HIV transmission in human palatine tonsil.

The majority of newly acquired HIV infections are believed to occur following transmission of virus infectivity across mucosal surfaces, although many mechanistic details still remain unresolved. We have used human ex vivo organ cultures and primary cell populations to analyze the cellular and molecular basis for mucosal HIV transmission. By using human palatine tonsil from routine tonsillectomies and semen from HIV-positive donors, we have created an experimental equivalent to oral HIV transmission. HIV infection was readily transferred into tonsillar lymphocytes, but this transmission into lymphocytes was dramatically reduced when the exposed lymphocyte populations were protected by intact mucosal surfaces. In this study, we consider the impact that leukocyte activation and morphological aberrations in surface structure may have on susceptibility to primary HIV infection and introduce novel time-lapse confocal microscopy procedures that begin to reveal the dynamic complexity associated with cell-mediated HIV transmission.     

The Rise and Fall of HIV in High-Prevalence Countries: A Challenge for Mathematical Modeling

Several countries with generalized, high-prevalence HIV epidemics, mostly in sub-Saharan Africa, have experienced rapid declines in transmission. These HIV epidemics, often with rapid onsets, have generally been attributed to a combination of factors related to high-risk sexual behavior. The subsequent declines in these countries began prior to widespread therapy or implementation of any other major biomedical prevention. This change has been construed as evidence of behavior change, often on the basis of mathematical models, but direct evidence for behavior changes that would explain these declines is limited. Here, we look at the structure of current models and argue that the common “fixed risk per sexual contact" assumption favors the conclusion of substantial behavior changes. We argue that this assumption ignores reported non-linearities between exposure and risk. Taking this into account, we propose that some of the decline in HIV transmission may be part of the natural dynamics of the epidemic, and that several factors that have traditionally been ignored by modelers for lack of precise quantitative estimates may well hold the key to understanding epidemiologic trends.     

Transmission patterns of HIV and hepatitis C virus among networks of people who inject drugs

Background

The risk-related behaviours and practices associated with injection drug use remain a driver of HIV and hepatitis C virus (HCV) transmission throughout the world. Here we evaluated HIV and HCV transmission patterns in the context of social networks of injection drug users (IDU) recruited from a higher incidence region in order to better understand factors that contribute to ongoing transmission among IDU.

Methods

IDU recruited through a chain-referral method provided biological specimens for analysis. HIV and HCV positive specimens were sequenced and analyzed using phylogenetic methods (Neighbour-joining and Bayesian) and transmission patterns of HIV and HCV evaluated in the context of the recruitment networks.

Results

Among the 407 recruited IDU, HCV and HIV prevalence were 60.6% and 10.1%, respectively; 98% of HIV positive individuals were co-infected with HCV. Thirty-six percent of HCV sequences were associated with clusters, compared to 67% of HIV sequences. Four (16.7%) of the 24 HCV clusters contained membership separated by 2 or fewer recruitment cycles, compared to 10 (41.6%) derived from more than one recruitment component. Two (28.6%) of the 7 HIV clusters contained membership separated by 2 or fewer recruitment cycles while 6 (85.7%) were composed of inter component membership.

Conclusions

Few HIV and HCV transmissions coincided with the recruitment networks, suggesting that they occurred in a different social context or a context not captured by the recruitment network. However, among the complete cohort, a higher degree of HIV clustering indicates many are recent infections originating from within current social networks, whereas a larger proportion of HCV infections may have occurred earlier in injecting history and in the context of a different social environment.