AIDS in Africa: an epidemiologic paradigm

Cases of the acquired immune deficiency syndrome (AIDS) have been reported in countries throughout the world. Initial surveillance studies in Central Africa suggest an annual incidence of AIDS of 550 to 1000 cases per million adults. The male to female ratio of cases is 1:1, with age- and sex-specific rates greater in females less than 30 years of age and greater in males over age 40. Clinically, AIDS in Africans is often characterized by a diarrhea-wasting syndrome, opportunistic infections, such as tuberculosis, cryptococcosis, and cryptosporidiosis, or disseminated Kaposi's sarcoma. From 1 to 18% of healthy blood donors and pregnant women and as many as 27 to 88% of female prostitutes have antibodies to human immunodeficiency virus (HIV). The present annual incidence of infection is approximately 0.75% among the general population of Central and East Africa. The disease is transmitted predominantly by heterosexual activity, parenteral exposure to blood transfusions and unsterilized needles, and perinatally from infected mothers to their newborns, and will continue to spread rapidly where economic and cultural factors favor these modes of transmission. Prevention and control of HIV infection through educational programs and blood bank screening should be an immediate public health priority for all African countries.     

Antibodies to the core protein of lymphadenopathy-associated virus (LAV) in patients with AIDS

Lymphadenopathy-associated virus ( LAV ), a human T- lymphotrophic retrovirus isolated from a homosexual man with lymphadenopathy, has been causally associated with acquired immunodeficiency syndrome (AIDS). A sensitive and specific radioimmunoprecipitation test was developed for the detection of antibodies to the major core protein of LAV , p25 (molecular weight 25,000). Antibody to LAV p25 was found in the serum of 51 of 125 AIDS patients, 81 of 113 patients with lymphadenopathy syndrome, 0 of 70 workers at the Centers for Disease Control (some of whom had handled specimens from AIDS patients), and 0 of 189 random blood donors. Of a group of 100 homosexual men from San Francisco whose serum was obtained in 1978, only one had antibody to LAV p25; in contrast, of a group of 50 homosexual men in the same community whose serum was obtained in 1984, 12 had antibodies to LAV p25.     

Seroprevalence and epidemiological correlates of HTLV-I infection in U.S. blood donors

Screening for human T-lymphotropic virus type I (HTLV-I) antibodies was performed on sera from 39,898 blood donors at eight blood centers in geographically distinct areas of the United States. Ten donors (0.025 percent) showed evidence of HTLV-I seropositivity by enzyme immunoassays; this was confirmed by protein immunoblot and radioimmunoprecipitation. Seroprevalence rates ranged from 0 to 0.10 percent at the locations sampled, with HTLV-I antibodies found predominantly in donors from the southeastern and southwestern United States. Matched case-control interviews and laboratory studies were performed on five seropositive women and two seropositive men who participated in an identity-linked collection of sera from a subset of 33,893 donors at six of the eight blood centers. Four of the women and both men are black; one woman is Caucasian. Four of the seven seropositive individuals admitted to prior intravenous drug abuse or sexual contact with an intravenous drug user. Sexual contact with native inhabitants of an HTLV-I endemic area was the only identified risk factor for one male. The distribution of HTLV-I antibodies in this U.S. blood donor sample corroborates the previously reported epidemiology of this agent and suggests that additional donor screening measures, including the testing of donated blood for HTLV-I markers, may be necessary to prevent the spread of HTLV-I to transfusion recipients.     

Long-term cultures of HTLV-III--infected T cells: a model of cytopathology of T-cell depletion in AIDS

Long-term cultures were established of HTLV-III-infected T4 cells from patients with the acquired immune deficiency syndrome (AIDS) and of T4 cells from normal donors after infection of the cells in vitro. By initially reducing the number of cells per milliliter of culture medium it was possible to grow the infected cells for 50 to 60 days. As with uninfected T cells, immunologic activation of the HTLV-III-infected cells with phytohemagglutinin led to patterns of gene expression typical of T-cell differentiation, such as production of interleukin-2 and expression of interleukin-2 receptors, but in the infected cells immunologic activation also led to expression of HTLV-III, which was followed by cell death. The results revealed a cytopathogenic mechanism that may account for T4 cell depletion in AIDS patients and suggest how repeated antigenic stimulation by infectious agents, such as malaria in Africa, or by allogeneic blood or semen, may be important determinants of the latency period in AIDS.     

Aging increases susceptibility of mouse skin to DMBA carcinogenesis independent of general immune status

The dependence of chemical carcinogenesis on age of target tissue was studied by repeated DMBA-treatment of mouse skin grafted from old and young syngeneic donors to young recipients. Carcinomas developed on 39 percent (1.6/41) of grafts from old donors and on 12 percent (5/41) of grafts from young donors. The incidence of nonskin lymphoid tumors was highest in male recipients bearing grafts from old donors.     

Transfer factor: delayed hypersensitivity to Schistosoma mansoni and tuberculin in Macaca mulatta

Delayed hypersensitivity in Macaca mulatta infected with either Schistosoma mansoni or mycobacteria was demonstrated by biopsies of skin test sites. Both dialyzable and nondialyzable leukocyte extracts from infected donors transferred delayed hypersensitivity to recipient monkeys. In two recipients, skin test conversion was associated with in vitro transformation of the recipients' lymphocytes.     

小型农牧场及农户波尔山羊胚胎移植关键技术研究

从小型农牧场及农户特点出发,探讨在这些场(户)进行波尔山羊胚胎移植时,供体超数排卵、受体同期发情、供受体羊胚胎回收和移植操作等关键技术对胚胎移植效率的影响。结果表明,调整供、受体母羊的发情周期并采用优化超排程序和同期发情程序,可获得理想的超排和同期发情结果,有效手术供体回收卵数平均达到(17.31±6.93)枚,可用胚(14.96±6.28)枚;受体同期发情率达到94.28%(2125/2254),手术受体利用率为86.55%(1602/1851)。严格而熟练的手术操作可提高供体利用次数,获得理想的胚胎移植结果,将2648枚胚胎移植给1602只受体后,妊娠率达到66.85%(1071/1602),其中1044只受体妊娠足月,产羔1320只。     

Medicine. Consent from donors for embryo and stem cell research

As research with human embryos and embryonic stem cells proceeds, the authors of this Policy Forum argue that all donors of biological materials should give informed consent, including oocyte and sperm donors. Informed consent is particularly important because of the diverse opinions and strong emotions that surround such research. Some gamete donors who are willing to help women and couples bear children may object to the use of their genetic materials for certain types of research.     

应用胚胎移植技术加速安哥拉山羊的繁殖

应用促卵泡素(FSH)配合促黄体素(LH)对17只安哥拉母羊进行超排处理。用药后2.5～3.5天全部发情,17只均有超排反应,平均排卵点13.56个,得到可用的胚胎9.76枚。用PG、PG组合、孕酮+PG3种处理,对受体进行同期发情处理,发情率分别为88.8％、96.6％和85.1％,利用率分别为65.1％、84.4％和63.8％。3年共移植102只,怀孕55只,受胎率53.9％,产羔52只,平均每只供体胚移产羔3.06只。17只供体采胚后还发情配种15只,当年产羔17只。供体年平均产羔率406％。     

Induction of AIDS-like disease in macaque monkeys with T-cell tropic retrovirus STLV-III

The T-cell tropic retrovirus of macaque monkeys STLV-III has morphologic, growth, and antigenic properties indicating that it is related to HTLV-III/LAV, the etiologic agent of the acquired immune deficiency syndrome (AIDS) in humans. Four of six rhesus monkeys died within 160 days of STLV-III inoculation with a wasting syndrome, opportunistic infections, a primary retroviral encephalitis, and immunologic abnormalities including a decrease in T4+ peripheral blood lymphocytes. These data show that an immunodeficiency syndrome can be produced experimentally in a nonhuman primate by an agent from the HTLV-III/LAV group of retroviruses. The STLV-III-macaque system will thus provide a useful model for the study of antiviral agents and vaccine development for human AIDS.     

A model-based estimate of the mean incubation period for AIDS in homosexual men

Because of the difficulty in identifying the date of exposure to type 1 of the human immunodeficiency virus (HIV-1) infection in persons other than transfusion recipients, studies of the incubation periods for acquired immunodeficiency syndrome (AIDS) have been limited. When data from a cohort of 84 homosexual and bisexual men that provided the information to determine the years of conversion of sera infected with HIV-1 were analyzed, a model for the proportion likely to develop AIDS and the incubation period for AIDS in homosexual men could be derived. The maximum likelihood estimate for the proportion of infected homosexual men developing AIDS is 0.99 (90% confidence interval ranging from 0.38 to 1). Furthermore, the maximum likelihood estimate for the mean incubation period for AIDS in homosexual men is 7.8 years (90% confidence interval ranging from 4.2 years to 15.0 years), which is close to the estimate of 8.2 years for adults developing transfusion-associated AIDS.     

Mammary cancer induction by 7,12-dimethylbenz(a)anthracene: relation to age

Mammary glands were transplanted from donors treated with 7,12-dimethylbenz(a)anthracene to untreated isologous recipients. Incidence of mammary tumors in mammary grafts from 56-day-old donors was significantly higher than that in grafts from 120-day-old donors, regardless of the age of the recipient hosts. Whent mammary glands were transplanted from untreated donors to isologous recipients that subsequently received 7,12-dimethyl-benz(a)anthracene, a similar difference in tumor incidence in the grafts was observed. In contrast to mammary glands of older females, mammary glands of young adult female rats are highly vulnerable to the carcinogenic effect of 7,12-dimethylbenz(a)anthracene.     

特克赛尔肉羊胚胎移植效果

2003～2005年,共同期发情处理特克赛尔供体母羊60只,发情58只,同期发情率达96.67%;同期发情处理受体母羊337只,发情325只,同期发情率达96.44%。2003年超排处理特克赛尔供体母羊14只,查黄体142个,采用输卵管冲胚技术回收卵137枚,回收率96.48%,可用胚126枚,移植鲜胚126枚,移植受体羊97只,受胎率56.7%。2004～2005年超排处理特克赛尔供体母羊46只,查黄体485个,采用子宫冲胚技术回收卵403枚,回收率83.09%,有效胚327枚,移植鲜胚217枚,鲜胚移植受体羊186只,受胎率54.92%;制作冻胚110枚,移植冻胚104枚,冻胚移植受体羊80只,未返情受体羊数41只,受胎率51.25%。     

Dual infection of the central nervous system by AIDS viruses with distinct cellular tropisms

Human immunodeficiency virus (HIV) is the causative agent of the acquired immune deficiency syndrome (AIDS). A large number of AIDS patients show evidence of neurologic involvement, known as AIDS-related subacute encephalopathy, which has been correlated with the presence of HIV in the brain. In this study, two genetically distinct but related viruses were isolated from one patient from two different sources in the central nervous system: brain tissue and cerebrospinal fluid. Both viruses were found to replicate in peripheral blood lymphocytes, but only virus from brain tissue will efficiently infect macrophage/monocytes. The viruses also differ in their ability to infect a brain glioma explant culture. This infection of the brain-derived cells in vitro is generally nonproductive, and appears to be some form of persistent or latent infection. These results indicate that genetic variation of HIV in vivo may result in altered cell tropisms and possibly implicate strains of HIV with glial cell tropism in the pathogenesis of some neurologic disorders of AIDS.     

The role of mononuclear phagocytes in HTLV-III/LAV infection

Cells with properties characteristic of mononuclear phagocytes were evaluated for infectivity with five different isolates of the AIDS virus, HTLV-III/LAV. Mononuclear phagocytes cultured from brain and lung tissues of AIDS patients harbored the virus. In vitro-infected macrophages from the peripheral blood, bone marrow, or cord blood of healthy donors produced large quantities of virus. Virus production persisted for at least 40 days and was not dependent on host cell proliferation. Giant multinucleated cells were frequently observed in the macrophage cultures and numerous virus particles, often located within vacuole-like structures, were present in infected cells. The different virus isolates were compared for their ability to infect macrophages and T cells. Isolates from lung- and brain-derived macrophages had a significantly higher ability to infect macrophages than T cells. In contrast, the prototype HTLV-III beta showed a 10,000-fold lower ability to infect macrophages than T cells and virus production was one-tenth that in macrophage cultures infected with other isolates, indicating that a particular variant of HTLV-III/LAV may have a preferential tropism for macrophages or T cells. These results suggest that mononuclear phagocytes may serve as primary targets for infection and agents for virus dissemination and that these virus-infected cells may play a role in the pathogenesis of the disease.     

Correction: AIDS commission

A recent article by William Booth on the President's AIDS commission (News & Comment, 16 Oct., p. 262) incorrectly states that commission member Cory SerVaas, publisher of the Saturday Evening Post, drives her AIDS Mobile around the country. SerVaas does not drive the traveling van that offers free AIDS testing. Rather, she often flies to meet it as it travels around the country, stopping at shopping malls and churches by prearrangement with local civic and religious groups. SerVaas denies saying that homosexuals are "deviants." "We have helped homosexuals for many years," she says, pointing out that although her group primarily tests people who have a low risk of being infected, such as recipients of blood transfusions and women who may become pregnant, members of high-risk groups such as homosexuals and drug addicts are not excluded.     

波尔山羊批量胚胎移植莎能奶山羊

采用阴道栓 FSH超数排卵,经产供体波尔山羊22只,在放栓后第9～11天,连续4d递减量肌肉注射FSH。22只供体羊发情与纯种波尔山羊种公羊配种后第7天,手术回收输卵管中早期发育胚胎再经手术移入同期发情的受体奶山羊输卵管内妊娠产仔。结果表明:1获得373枚早期胚胎,其中A级胚胎占31.1%(85/273),B级胚胎占49.5%(135/273),异常胚胎占19.4%(53/273)。2将167枚7日龄可用胚胎(A级和B级)移植147只受体羊输卵管内,移植后35d,妊娠98只,妊娠率为67%(98/147),83只羊足月产羔为89只,产羔率为85%(89/98),20只受体移植了两枚胚胎,只有6只产双羔。3羔羊出生重平均为3.7±0.54kg。每只供体羊平均产羔4.05只。胚胎移植所得羔羊的初生重与自然繁殖波尔羔羊无显著差异(P>0.05)。试验证明,山羊胚胎移植计划可使良种群体繁殖率提高3～5倍,优秀个体繁殖力提高6～8倍,从而加快纯种山羊的繁殖。     

南德温牛胚胎移植研究

为了研究适于大型肉牛———南德温牛的超数排卵及胚胎移植技术,选择11头适龄南德温牛为供体牛和9头南阳牛为受体牛,进行CIDR-FSH-PG超数排卵和胚胎移植试验。结果表明,供体牛均按时发情,反应率100%,共采胚99枚,获可用胚胎65枚,平均每头5.91枚,可用胚胎率65.0%,可用胚胎等级A、B、C级分别为38.5%、30.8%、30.7%,共移植受体9头,妊娠6头,受胎率66.67%,共产犊9头,其中产双犊3头,其余胚胎进行了冷冻保存。     

AIDS meeting. Companies, donors pledge to close gap in AIDS treatment

Although basic science and clinical research typically dominate at this biennial event, by far the most riveting sessions at the XIII International AIDS Conference here revolved around the thicket of issues that prevent poor people in sub-Saharan Africa--where a staggering 24.5 million people are estimated to be infected with HIV--from receiving the 14 anti-HIV treatments now used in wealthy countries. Pharmaceutical companies and donors last week loosed a flood of promises about removing barriers. Conference attendees welcomed the offers of help, but many stressed that much more will be needed.     

波尔山羊活体采卵与卵母细胞体外受精技术

对10只不孕不育波尔母山羊采用超数排卵、活体采卵、卵母细胞体外成熟培养以及体外受精等技术方法,探讨其是否能正常繁育后代。试验中6只供体经超数排卵处理,在发情前利用特制的采卵装置进行活体采卵,共采集到30枚形态学正常的卵母细胞。经过体外成熟培养,有21枚成熟卵母细胞进行了体外受精处理和培养,获得16枚2 细胞胚胎,移植到4只同期发情的当地山羊受体输卵管内,经妊娠检验,有两只受体受孕,其中1只受体产出正常羔羊2只。该技术经进一步改进完善后可望作为不孕不育波尔山羊繁殖后代的辅助生育技术。