Electrical power fuels rotary ATP synthase

ATP synthesis by F-type ATP synthases consumes energy stored in a transmembrane electrochemical gradient of protons or sodium ions. The electric component of the ion motive force is crucial for ATP synthesis. Here, we incorporate recent results on structure and function of the F(0) domain and present a mechanism for torque generation with the fundamental nature of the membrane potential as driving force in the core.     

HIV/AIDS epidemic in Eastern Europe: Recent developments in the Russian Federation and Ukraine among women

Background: The Russian Federation and the Ukraine are among the Eastern European countries with the fastest growing number of cases of HIV. According to data from the Joint United Nations Program on HIV/AIDS, nearly 90% of newly reported HIV diagnoses in Eastern Europe in 2006 were from the Russian Federation (66%) and the Ukraine (21%). A growing number of women are infected with HIV. The impact of gender on HIV/AIDS is an important factor in understanding the development and evolution of the HIV/AIDS epidemic in Eastern Europe.Objective: The aim of this study was to assess the importance of integrating gender consideration into the creation of HIV programs and to examine the effect of gender on HIV/AIDS.Methods: Reported HIV/AIDS cases from the official epidemiological register of the Ukrainian Centre for AIDS Prevention alongside data from the Russian Federal AIDS Center were analyzed. Joint United Nations Program on HIV/AIDS country fact sheets were reviewed and analyzed, and this information was supplemented with published HIV prevalence and sexually transmitted disease case reporting information, unpublished reports, and expert evaluations.Results: Of the newly registered cases of HIV, the proportion of women rose from 13.0% in 1995 to 44.0% in 2006 in the Russian Federation, and from 37.2% in 1995 to 41.9% in 2006 in the Ukraine. There has also been a considerable increase in mother-to-child transmission of HIV since 1995. Between 1987 and 1994, the proportion of children among the people newly infected with HIV in the Ukraine was 2.2%; in 2006 it was 17.6%. In 2006, 16,078 new HIV cases were registered in the Ukraine and 39,652 new HIV cases in the Russian Federation. Large increases in the number of HIV-infected women were reported from both countries.Conclusions: The data examined in this study suggest subregional differences in the magnitude of the HIV/AIDS epidemic in the Russian Federation and the Ukraine and the importance of the impact of gender on the rapid spread of the HIV/AIDS epidemic among women and women of child-bearing age. To protect women from HIV infection, it is important to find ways to empower them by implementing policies and specific prevention measures that increase their access to knowledge about HIV/AIDS; the empowerment of women is vital to reversing the HIV/AIDS epidemic.     

On transient effects in the HIV/AIDS epidemic

During the initially exponential spread of the human immunodeficiency virus (HIV—the causative agent of AIDS) the growth rate of the number of AIDS cases decreases from plus infinity to the growth rate of HIV infections. A sensitivity analysis shows that for all reasonable values of the parameters of the HIV epidemic (incubation period, initial doubling time, etc.) the effect of this positive transient becomes negligible when the annual number of AIDS cases reaches a few dozen. Necessary and sufficient conditions are given for the growth rate of the number of AIDS cases to be monotonically decreasing during the positive transient. A mildly pathological density function for the incubation period of AIDS provides an example of a growth rate of AIDS that does not decrease monotonically, even though HIV is spreading exponentially. A negative transient occurs when the growth rate of HIV begins to decrease. In this context a somewhat surprising result emerges under the assumption that the growth rate of HIV is non-increasing: the growth rate of AIDS is at all times larger than the growth rate of HIV. A logistic HIV epidemic illustrates this result, and implications for the growth of the HIV epidemic in the United States and Europe are discussed. In particular, it is shown that the positive transient must have passed by 1982 in the United States and by 1986 or 1987 for the five European countries with the largest caseloads.     

Specific features of the HIV infection epidemic in Moscow

Retrospective analysis of the epidemic of HIV infection in Moscow allowed to mark out two periods: the first--from 1987 to 1993 and the second one--from 1994 to 2000. The characteristic feature of the first period of the epidemic was the sexual transmission of the agent mainly among homosexuals; the most affected group were persons aged 20-39 years and the number of AIDS patient decreased with a simultaneous growth in lethality. During the second stage of the HIV infection epidemic changes in the prevailing transmission routes of the agent occurred: injection drug addicts took the leading role. Changes in the ratio of HIV-infected men and women took place along with active involvement of persons aged 13-18 years into the epidemic process. The established changes in the epidemiological situation require corrections in the strategy and tactics of epidemic control and prophylactic measures.     

Estimating the size of the HIV epidemic by using mortality data

Evidence that more people are dying as a result of HIV infection than is reflected by the number of deaths among reported cases meeting the WHO definition of AIDS is derived from mortality data. Ninety-five causes of death likely to be associated with HIV infection were selected. Standardized mortality ratios due to these causes increased for single men aged 15-54 years from 100 in 1984 to 118 in 1987. The age, sex, marital status, temporal and geographic distribution of these excess deaths suggest that they are HIV-associated. It is estimated that 58% of excess deaths due to HIV-related causes were among cases reported to the CDSC AIDS Surveillance Programme in 1987. Some of these deaths may have been among HIV-positive people who did not meet the WHO definition at the time of death. There is a need for surveillance to be extended to include HIV-positive people who die before meeting the WHO definition if the full extent of the HIV epidemic is to be identified.     

The HIV/AIDS epidemic in sub-Saharan Africa

Knowledge useful to the fight against HIV/AIDS in sub-Saharan Africa cannot be extrapolated to those coming from industrialized countries. The aim of this article is to review specificities of the African epidemy, in terms of epidiomolgy, natural history, validated therapeutic interventions, and unexplored questions. Far from being without effective tools and research tracks to fight against this plague which decimates a continent, one is above all confronted with a deficit of both mobilization and means.     

The HIV epidemic: medical and social challenges

The sudden appearance, rapid spread, and devastating clinical impact of HIV infection in Africa, Europe and North America has created a medical problem unprecedented in the modern era. HIV is sexually transmitted, afflicts sexual and racial minorities in developed countries, and appears likely to be fatal and incurable in a majority of infected people. Its epidemiology (transmission and natural history) and clinical manifestations have been well described, but treatment of HIV remains minimally effective, creating only a short respite from progressive deterioration. In the absence of effective vaccination, HIV will continue to spread, abetted by a long period of asymptomatic carriage during which carriers are infectious. It has spread internationally to most undeveloped countries aided by fear and ignorance. The problem will resist simple technological solutions and adversely impact the lives of tens of millions of people in these areas over the next several decades. In developed countries HIV will strain medical resources and kill several million people before the end of the century. Despite the tremendous problems created by the AIDS epidemic, it has driven a remarkable expansion of virologic and immunologic understanding which promises to ultimately lead to control of not only AIDS, but a variety of other serious diseases. The following reviews of pivotal issues in AIDS research document this progress.     

Marrying women 15 years younger maximized men's evolutionary fitness in historical Sami

Most men marry younger women. This has been attributed to men selecting young women due to their high reproductive value and women preferring older men due to their wealth and high social status. Such mate preferences have been suggested to be adaptive, but despite a flourishing number of studies on the mate selection patterns themselves, little is still known of their actual fitness consequences. We examined how the age difference between spouses who married only once affected their lifetime reproductive success in historical monogamous Sami populations. We found that men maximized their fitness by marrying women approximately 15 years younger and vice versa. However, most couples failed to marry optimally. Only 10% of marriages fell within the optimal parental age difference, suggesting that cultural and ecological constraints for maximizing fitness were considerable. Those who succeeded in marrying optimally were the most preferred partners: young women and old men. Our findings indicate that, in Sami, parental age difference was under natural and sexual selection, as suggested by evolutionary theory.     

Accomplishments in HIV prevention science: implications for stemming the epidemic

The past two decades have witnessed substantial advances in the science of preventing HIV infection. Although important issues remain and there is a need for continuing research, arguably the biggest challenge in preventing HIV transmission is the full implementation of existing preventive interventions worldwide.     

Infertility in African countries: challenges created by the HIV epidemic

¹ Correspondence address. E-mail: silke.dyer{at}uct.ac.za HIV infection and infertility are two common reproductive healthdisorders in Africa. From the perspective of infertility-relatedreproductive health care, the HIV epidemic has created severalchallenges which include reduction of fecundity, depletion ofscarce health resources, creation of barriers to infertilitytreatment and increased suffering. Infertility in turn is arisk factor for HIV acquisition and a possible force in thespread of the HIV epidemic. Recognition of the reproductivehealth needs and desires of HIV-infected infertile men and womenis a prerequisite for addressing these challenges. Subsequentstrategies comprise the development of treatment guidelinesfor low-resource environments and a greater integration of HIVand sexual and reproductive health services. Where resourcesfor infertility treatment are not available, the consequencesmust be critically assessed.