Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

'Dry sex' refers to the preference for a dry, tight vagina during sexual intercourse. Women in Zimbabwe and elsewhere have been found to use a variety of drying agents to achieve these effects. Previous studies of 'dry sex' have concentrated on documentation of the practice and investigation of any associated increased risk of HIV. In contrast, this study examines the impact of 'dry sex' on condom use and effectiveness. Focus group interviews were held with female HIV/AIDS peer educators in Zimbabwe who had a history of commercial sex work. Participants reported that drying agents had physical and psychological consequences. That is, agents were said to dry and tighten a woman's vagina, and also to serve as 'love potions' to attract sexual partners and ensure their faithfulness. Although vaginal dryness was not found to deter the use of condoms, some women were reluctant to use condoms for fear of blocking the 'magic' of drying agents. There was agreement among participants that condoms frequently broke when used in conjunction with drying agents. Participants primarily attributed condom breakage to excessive vaginal tightness. Lubricants were not routinely used during sex or with condoms. However, participants preferred the use of lubricated condoms when they used condoms. Implications of the 'dry sex' practice for AIDS prevention programs and development of new HIV prevention technologies are discussed.
 ...
PMID:Dry sex in Zimbabwe and implications for condom use. 874 10

The objective of this study was to examine the potential of vaginal and rectal mucosal routes for feline immunodeficiency virus (FIV) uptake and infection, as a model of mucosal HIV infection, and to determine the fate of virus at these mucosal sites following transmission of infection. SPF cats were exposed to FIV isolates (PET, GL-8, T637), administered as either cell-associated or cell-free inocula, via the rectum or vagina. Establishment of infection was confirmed by isolation of infectious FIV from peripheral blood mononuclear cells (PBMC), and by presence of FIV proviral DNA in PBMC using a nested polymerase chain reaction. Fate of virus in tissue taken at necropsy from cats infected for 6-48 weeks was assessed by localizing FIV core and envelope proteins, p24 and gp41, using a biotin-streptavidin linked immunoperoxidase (IP) technique. Cells susceptible to infection were identified by an in situ hybridization technique for FIV viral DNA and RNA. Cell-free, as well as cell-associated, virus was infectious across intact vaginal and rectal mucosal surfaces. Transmission was most successful using cell-associated inocula, and via the rectal route. Cells infected with FIV were detected by IP staining in the colon of 6/9 rectally challenged cats and 1/5 vaginally challenged cats. Virus was predominantly localized within the epithelium at the base of the colonic crypts associated with lymphoid aggregates (follicle associated epithelium; FAE), and within the lymphoid follicle itself. Occasional infected cells were also noted within the lamina propria. The distribution of FIV DNA positive cells in the colon was similar to that for FIV antigen whilst FIV RNA positive cells were found more extensively, including within the lamina propria and lymphoid follicle. FIV infected cells were not detected within the vagina, or colonic and ileac lymph nodes. Similar patterns of infected cells were seen in all of the positive cats, indicating that colonic tissues remain persistently actively infected with FIV. We conclude that the FIV/cat model of rectal and vaginal mucosal infection should prove useful for characterizing the mechanism by which HIV infects mucosal surfaces and as a challenge system for the design of vaccines effective at preventing HIV infection via rectal and vaginal routes.
 ...
PMID:Vaginal and rectal infection of cats with feline immunodeficiency virus. 887 Jan 85

The two major foci of HIV-1 infection in Asia, Thailand and India, have separate HIV-1 epidemics related to distinct HIV-subtypes. By the late 1980s or early 1990s, there were two distinct HIV-1 epidemics in India. One epidemic, particularly in Manipur region, was typical of intravenous (IV) drug-associated epidemics and was likely due to subtype B. The other has the patterns of a typical sexually transmitted disease and was likely due to subtype C. The two epidemics in Thailand follow a similar delineation to those in India. Yet, unlike India, a new HIV-1 has emerged, HIV-1 E, in both epidemics. Subtypes C and E viruses from Asia are associated with efficient heterosexual transmission. These HIV-1 subtypes grow considerably better in Langerhans' cells (highly prevalent in tissues of the vagina, cervix, and penis foreskin and almost absent from the rectum) than does HIV-1 subtype B. HIV-1 B viruses appear to have lost their affinity for efficient heterosexual transmission through mutation, suggesting that HIV-1 B can be maintained in groups where transmission by vaginal sex is not needed (i.e., high density of contacts with homosexuals and/or IV drug users). A homogeneous, heterosexual population with the highest incidence of new HIV-1 infections, which is exposed to the same viral subtype or strain, is the ideal test population for designing and testing an HIV-1 vaccine. The ideal HIV-1 test vaccine is the polymerized envelope antigen gp120. The safety of live attenuated HIV vaccines is doubtful. It appears that HIV-2infection provides some protection against HIV-1 infection (cross-reactivity immunity). In conclusion, trials of HIV-1 vaccines are needed but should use HIV-1 C or E strains that spread rapidly by vaginal sex. These strains can be isolated from vaginal fluids with tropism for Langerhans' cells.
 ...
PMID:Retroviral vaccines: challenges for the developing world. 888 11

Chimeric simian/human immunodeficiency virus (SHIV) consists of the env, vpu, tat, and rev genes of human immunodeficiency virus type 1 (HIV-1) on a background of simian immunodeficiency virus (SIV). We derived a SHIV that caused CD4+ cell loss and AIDS in pig-tailed macaques (S. V. Joag, Z. Li, L. Foresman, E. B. Stephens, L. J. Zhao, I. Adany, D. M. Pinson, H. M. McClure, and O. Narayan, J. Virol. 70:3189-3197, 1996) and used a cell-free stock of this virus (SHIV(KU-1)) to inoculate macaques by the intravaginal route. Macaques developed high virus burdens and severe loss of CD4+ cells within 1 month, even when inoculated with only a single animal infectious dose of the virus by the intravaginal route. The infection was characterized by a burst of virus replication that peaked during the first week following intravenous inoculation and a week later in the intravaginally inoculated animals. Intravaginally inoculated animals died within 6 months, with CD4+ counts of <30/microl in peripheral blood, anemia, weight loss, and opportunistic infections (malaria, toxoplasmosis, cryptosporidiosis, and Pneumocystis carinii pneumonia). To evaluate the kinetics of virus spread, we inoculated macaques intravaginally and euthanized them after 2, 4, 7, and 15 days postinoculation. In situ hybridization and immunocytochemistry revealed cells expressing viral RNA and protein in the vagina, uterus, and pelvic and mesenteric lymph nodes in the macaque euthanized on day 2. By day 4, virus-infected cells had disseminated to the spleen and thymus, and by day 15, global elimination of CD4+ T cells was in full progress. Kinetics of viral replication and CD4+ loss were similar in an animal inoculated with pathogenic SHIV orally. This provides a sexual-transmission model of human AIDS that can be used to study the pathogenesis of mucosal infection and to evaluate the efficacy of vaccines and drugs directed against HIV-1.
 ...
PMID:Animal model of mucosally transmitted human immunodeficiency virus type 1 disease: intravaginal and oral deposition of simian/human immunodeficiency virus in macaques results in systemic infection, elimination of CD4+ T cells, and AIDS. 909 79

Previous studies have shown that HIV-1 exploits dendritic cells (DCs) to replicate and spread among CD4+ T cells. The DCs within mucosal surfaces may be especially important, but these are more difficult to access. To study more extensively the properties of DCs and other leukocytes from skin and different mucosae, DCs were isolated from uninfected macaques and their sensitivity assessed to infection with SIV in vitro. Dendritic cells and T cells readily emigrated from organ cultures of macaque skin, as described previously for humans. In addition, characteristic cells emigrated from explants of mucosae, both nasopharyngeal (adenoid and tonsil) and genital (vagina and cervix). The macaque DCs reacted with the monoclonals that are used to study human DCs, such as MAbs to CD40, CD86, CD83, and the p55 protein. When SIV was added to the DC-T cell mixtures from these different organs, extensive replication was observed in all but the cervical leukocytes. SIV replication occurred without the use mitogens, and with virus that had been grown in a cell line in the absence of mitogens and IL-2. Most of the newly synthesized viral protein is observed in syncytia. Therefore, mixtures of DCs and T cells isolated from mucosal surfaces served as a naturally permissive environment for SIV replication.
 ...
PMID:Dendrite cell-T cell mixtures, isolated from the skin and mucosae of macaques, support the replication of SIV. 919 76

A report that genetic subtype E human immunodeficiency virus type 1 (HIV-1) strains display a preferential tropism for Langerhans cells (epidermal dendritic cells [DCs]) compared to genetic subtype B strains suggested a possible explanation for the rapid heterosexual spread of subtype E strains in Thailand (L. E. Soto-Ramirez et al., Science 271:1291-1293, 1996). In an independent system, we applied subtype E and B isolates to skin leukocytes, since skin is a relevant model for the histologically comparable surfaces of the vagina and ectocervix. Isolates of both HIV-1 subtypes infected DC-T-cell mixtures, and no subtype-specific pattern of infection was observed. Purified DCs did not support the replication of strains of either subtype B or E. Our findings do not support the conclusion that subtype E strains have a preferential tropism for DCs, suggesting that other explanations for the rapid heterosexual spread of subtype E strains in Asia should be considered.
 ...
PMID:Human immunodeficiency virus type 1 strains of subtypes B and E replicate in cutaneous dendritic cell-T-cell mixtures without displaying subtype-specific tropism. 931 95

Prevention of sexually transmitted HIV infection was first investigated in non-human primates by mucosal immunization via the rectal, vaginal or male urethral route. This was compared with subcutaneous targeted iliac lymph node (TILN) and systemic intramuscular immunization in non-human primates. TILN immunization elicited the most consistent mucosal sIgA and IgG antibody response in the rectum, vagina, urine and seminal fluid, as well as in blood. Both mucosal and TILN immunization induced a specific CD4+ T cell proliferative response in the iliac lymph nodes which drain these mucosal surfaces, and in the splenic and circulating T cells. In the next experiment macaques were immunized by the TILN route with SIV gp120 and p27 in alum. Rectal mucosal challenge with SIVmac 32H J5 molecular clone (or cell-free virus) induced total protection in four out of seven macaques, compared with infection in 13 of 14 unimmunized macaques or immunized by other routes (p = 0.025). The remaining three macaques immunized by the TILN route showed either decrease in viral load (> 90%) or transient viraemia, indicating that all seven TILN immunized macaques showed total or partial protection of rectal transmission by SIV (p = 0.001). Protection was associated with significant increase in the iliac lymph nodes IgA antibody secreting cells to p27 (p < 0.02), CD8-suppressor factor inhibiting replication of SIV in CD4+ T cells (p < 0.01) and the chemokines RANTES and MIP-1 beta (p < 0.01). We suggest that administration of gp120 and p27 by the TILN route may elicit protective B and T cell immunity which can significantly prevent rectal transmission of SIV or HIV.
 ...
PMID:Protective mucosal immunity elicited by targeted lymph node immunization with a subunit SIV envelope and core vaccine in macaques. 955 79

Significant progress has been made in understanding the biology of heterosexual transmission of HIV by utilizing the simian immunodeficiency virus (SIV)/rhesus monkey animal model. Our previous studies have shown that SIV-infected cells within the stratified squamous epithelium of the vagina have a dendritic morphology. However, the type of cell infected was not conclusively determined. The purpose of the present study was to immunophenotype the SIV-infected cells in the lower reproductive tract and genital lymph nodes of the female rhesus monkey. Vagina, cervix, and iliac lymph node from eight chronically SIV-infected adult female monkeys were examined for this study. None of the animals had histologic evidence of opportunistic infections or genital tract pathogens other than SIV. Combined in situ hybridization and immunohistochemistry were used to detect SIV RNA and to determine the immunophenotype of SIV-infected cells in tissue sections and cytospin preparations of cells from the tissues. We now show that SIV-infected cells were most common in iliac lymph node and that the majority of infected cells in the lymph node were T lymphocytes. SIV-infected macrophages, Langerhans' cells, and dendritic cells were also found in the lymph node. SIV-infected cells were found within the epithelium and lamina propria of the vagina. Although most of the infected cells were T cells, a significant proportion (approximately 40%) of the SIV-infected cells in cytospin preparations from explant cultures of vagina and cervix were Langerhans' cells. SIV-infected T cells in the lower genital tract were commonly associated with focal mononuclear cell infiltrates. SIV-infected macrophages were rarely found in the genital tract. The present study provides the first direct demonstration that Langerhans' cells and dendritic cells in the genital tract and lymph nodes are infected with SIV in vivo. Thus, dendritic cells, in general, and Langerhans' cells, in particular, are important reservoirs for HIV/SIV replication in vivo.
 ...
PMID:Immunophenotypic characterization of simian immunodeficiency virus-infected dendritic cells in cervix, vagina, and draining lymph nodes of rhesus monkeys. 984 Jun 10

We have evaluated the in vivo distribution of the major human immunodeficiency virus/simian immunodeficiency virus (HIV/SIV) coreceptors, CXCR4, CCR3, and CCR5, in both rhesus macaques and humans. T lymphocytes and macrophages in both lymphoid and nonlymphoid tissues are the major cell populations expressing HIV/SIV coreceptors, reaffirming that these cells are the major targets of HIV/SIV infection in vivo. In lymphoid tissues such as the lymph node and the thymus, approximately 1 to 10% of the T lymphocytes and macrophages are coreceptor positive. However, coreceptor expression was not detected on follicular dendritic cells (FDC) in lymph nodes, suggesting that the ability of FDC to trap extracellular virions is unlikely to be mediated by a coreceptor-specific mechanism. In the thymus, a large number of immature and mature T lymphocytes express CXCR4, which may render these cells susceptible to infection by syncytium-inducing viral variants that use this coreceptor for entry. In addition, various degrees of coreceptor expression are found among different tissues and also among different cells within the same tissues. Coreceptor-positive cells are more frequently identified in the colon than in the rectum and more frequently identified in the cervix than in the vagina, suggesting that the expression levels of coreceptors are differentially regulated at different anatomic sites. Furthermore, extremely high levels of CXCR4 and CCR3 expression are found on the neurons from both the central and peripheral nervous systems. These findings may be helpful in understanding certain aspects of HIV and SIV pathogenesis and transmission.
 ...
PMID:In vivo distribution of the human immunodeficiency virus/simian immunodeficiency virus coreceptors: CXCR4, CCR3, and CCR5. 957 73

Using isolated cell suspensions and in situ techniques, we have partially characterized the organization, functional capacity, and sex hormone regulation of the mucosal immune system in the human female reproductive tract. Isolated cells suspensions have been used to demonstrate that the uterus contains antigen-presenting cells that are functionally able to present antigen to autologous tetanus toxoid-specific T cells. Immunophenotypic analyses of the female reproductive tract by three-color immunofluorescent staining has been used to show that lymphoid aggregates, which are absent in postmenopausal women, develop in the uterine endometrium during the menstrual cycle in premenopausal women. Lymphoid aggregates are composed of a B lymphocyte core surrounded by numerous CD8+CD4- T lymphocytes and an outer halo of macrophages. Macrophages, CD4+ and CD8+ T cells, and CD56+ NK cells are distributed throughout the uterine endometrium. In contrast, the Fallopian tube, cervix, and vagina, which lack lymphoid aggregates, contain CD8+ and CD4+ T cells as well as macrophages. The female reproductive tract has also been analyzed for the presence of antigen-independent CD3+ T lymphocyte cytolytic function by an anti-CD3 MAb-mediated redirected lysis assay. High levels of CD3+ T lymphocyte cytolytic activity were demonstrated in cervix and vagina and independent of stage of the menstrual cycle. In the uterus, cytolytic activity changed with endocrine state. In postmenopausal women the uterine endometrium had CD3+ T lymphocytes with high cytolytic activity, whereas premenopausal women had CD3+ T lymphocytes with moderate cytolytic potential during the proliferative phase to low/no cytolytic activity during the secretory phase of the menstrual cycle. In studies to determine whether the upper reproductive tract could be infected with HIV-1, we found on the basis of nef expression and p24 release that epithelial cells from the Fallopian tube, and from the uterus and cervix, are infectable. These studies demonstrate that the human female reproductive tract is an inductive site for immune responses and the cell-mediated immunity is present throughout the female reproductive tract. These studies further indicate that the Fallopian tube and uterus are potential entry sites for HIV-1 infection and that uterine immune cell architecture as well as cytolytic activity are under hormonal control.
 ...
PMID:The mucosal immune system in the human female reproductive tract: potential insights into the heterosexual transmission of HIV. 958 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>