某城市女性性工作者AIDS相关人口学和行为学变化情况调查

目的了解某沿海城市近年女性性工作者(FSW)人口学特征和艾滋病(AIDS)高危行为变化情况。方法2000～2003年连续4年对曾从事性工作的妇教所“学员”进行调查,并对调查结果进行比较。结果妇教所学员有逐渐减少趋势。共调查321位FSW,总样本平均年龄2637±694岁,未婚者占59%～74%,文化程度初中及以下者占80%以上,已婚妇女所占比例逐渐增加;从事性工作时无正当收入或低收入者占80%以上;非该市的流动人口占80%以上;个体服务者所占比例逐年增加;初次卖淫年龄2575±72岁,平均累计性伙伴1147±1519人。16%～29%曾患性病。安全套使用,特别是多数情况使用者逐年增加,商业性伙伴对安全套的态度明显影响FSW对安全套的使用。结论FSW人口学特征的改变使得AIDS干预的难度增加。FSW中安全套使用率的增加和主动检测艾滋病病毒抗体比例的增加,表明对大众的AIDS宣传能有效地影响到FSW,但需进一步在各种娱乐服务场所大力推广安全套。     

Why hunter-gatherer populations do not show signs of Pleistocene demographic expansions

The mitochondrial DNA diversity of 62 human population samples was examined for potential signals of population expansions. Stepwise expansion times were estimated by taking into account heterogeneity of mutation rates among sites. Assuming an mtDNA divergence rate of 33% per million years, most populations show signals of Pleistocene expansions at around 70,000 years (70 KY) ago in Africa and Asia, 55 KY ago in America, and 40 KY ago in Europe and the Middle East, whereas the traces of the oldest expansions are found in East Africa (110 KY ago for the Turkana). The genetic diversity of two groups of populations (most Amerindian populations and present-day hunter-gatherers) cannot be explained by a simple stepwise expansion model. A multivariate analysis of the genetic distances among 61 populations reveals that populations that did not undergo demographic expansions show increased genetic distances from other populations, confirming that the demography of the populations strongly affects observed genetic affinities. The absence of traces of Pleistocene expansions in present-day hunter-gatherers seems best explained by the occurrence of recent bottlenecks in those populations, implying a difference between Pleistocene (approximately 1,800 KY to 10 KY ago) and Holocene (10 KY to present) hunter-gatherers demographies, a difference that occurred after, and probably in response to, the Neolithic expansions of the other populations.     

Age-specific demographic profiles of longevity mutants in Caenorhabditis elegans show segmental effects

Demographic profiles of several single-gene longevity mutants of the nematode Caenorhabditis elegans reveal segmental (age-specific) effects on mortality. The mortality profiles of wild-type worms were examined across multiple replicate cultures containing 100,000 or more nematodes and found to be quite replicable, although clear environmental effects are routinely found. The combined profile of wild type was compared with those of three long-lived mutants to determine how age-specific mortality is altered by mutations in age-1, clk-1, or spe-26. In all four genotypes, death rates fit a two-stage Gompertz model better than a one-stage Gompertz; that is, mortality levels off at later ages. The largest genetic effect on mortality was that of an age-1 mutation, which lowered mortality more than fivefold at most later ages. In contrast, a spe-26 mutant had a tenfold lower mortality until approximately 2 weeks of age but ultimately achieved a higher mortality, whereas clk-1 mutants show slightly higher mortality than wild type during the fertile period, early in life, but ultimately level off at lower mortality. Each mutant thus has a distinctive profile of age-specific mortalities that could suggest the time of action of each gene.     

Patients with polymyositis show changes in muscle protein charges

Polymyositis (PM) appears with indolent proximal muscle weakness and is an inflammatory disease with breakdown of muscle cells. In our study the protein charge concentrations of the contractile proteins in the A and I bands were determined, applying a microelectrode technique. Patients with PM show a lower protein charge concentration than healthy control subjects which may be caused by the breakdown and removal of the proteins in the contractile filaments. A tool to judge the state of the disease as well as an aid in diagnosis may have been found in this method.     

New developments in AIDS

At the present time there is no effective therapy for the HIV infection itself, nor for the opportunistic infections, malignancies, immune perturbations, and other manifestations of AIDS. However, as a result of knowledge gained regarding the modes of transmission of HIV, public health officials have made recommendations which, if followed, would slow or even halt further spread of the virus. Thus it is hoped that educational efforts directed at individuals in high-risk groups will be effective in stopping transmission of this disease and that ongoing research efforts will soon provide therapeutic agents to cure it or slow its progression.     

Country-specific estimates and models of HIV and AIDS: methods and limitations

OBJECTIVE: This paper presents the methods used to calculate the end of 1997 country-specific estimates of HIV and AIDS produced by the UNAIDS/WHO Working Group on Global HIV/AIDS and STD Surveillance. The objective of this exercise was to improve estimates on HIV/AIDS by using country-specific models of HIV/AIDS epidemics. The paper describes and discusses the processes and obstacles that were encountered in this multi-partner collaboration including national and international experts. METHODS: The 1997 estimates required two basic steps. First, point prevalence estimates for 1994 and 1997 were carried out and the starting year of the epidemic was determined for each country. The procedures used to calculate the estimates of prevalence differed according to the assumed type of the epidemic and the available data. The second step involved using these estimates of prevalence over time and the starting date of the epidemic to determine the epidemic curve that best described the spread of HIV in each particular country. A simple epidemiological program (EPIMODEL) was used for the calculation of estimates on incidence and mortality from this epidemic curve. RESULTS: Regional models that were used in previous estimation exercises were not able to capture the diversity of HIV epidemics between countries and regions. The result of this first country-specific estimation process yielded higher estimates of HIV infection than previously thought likely, with over 30 million people estimated to be living with HIV/AIDS. The application of survival times that are specific to countries and regions also resulted in higher estimates of mortality, which more accurately describe the impact of the epidemics. At the end of 1997, it was estimated that 11.7 million people worldwide had died as a result of HIV/AIDS since the beginning of the epidemic. CONCLUSION: This exercise is an important step in improving understanding of the spread of HIV in different parts of the world. There are, however, shortcomings in the current systems of monitoring the epidemic. Improvements in HIV surveillance systems are needed in many parts of the world. In addition, further research is needed to understand fully the effects of the fertility reduction as a result of HIV, differing sex ratios in HIV infection and other factors influencing the course and measurement of the epidemic.     

AIDS Treatment News: changes next year

During the next year we must change our traditional business model. Also, we plan to do more reporting online, and continue the printed newsletter as well.     

New Federal AIDS funding announced

Health and Human Services awarded $710 million in new grant money to increase primary care access for people with HIV/AIDS. The Title II Ryan White Comprehensive AIDS Resource Emergency Act grants went to individual States, the District of Columbia, and U.S. territories. The grants are calculated based on the number of people with AIDS in a given area, New York City receiving the largest grant, over $127 million. State AIDS Drug Assistance Programs will also receive $461 million of the new funding.     

Integrating demographic and epidemiological approaches to research on HIV/AIDS: the proximate-determinants framework

This article presents a conceptual framework for the study of the distribution and determinants of human immunodeficiency virus (HIV) infection in populations, by combining demographic and epidemiological approaches. The proximate-determinants framework has been applied extensively in the study of fertility and child survival in developing countries. Key to the framework is the identification of a set of variables, called "proximate determinants," that can be influenced by changes in contextual variables or by interventions and that have a direct effect on biological mechanisms to influence health outcomes. In HIV research, the biological mechanisms are the components that determine the reproductive rate of infection. The proximate-determinants framework can be used in study design, in the analysis and interpretation of risk factors or intervention studies that include both biological and behavioral data, and in ecological studies.