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Query: UMLS:C0001175 (AIDS)
 120,706 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Infection of captive macaques with simian immunodeficiency virus (SIV) and domestic cats with feline immunodeficiency virus (FIV), both discovered in the last five years, represent excellent animal models for infection of humans with the human immunodeficiency virus (HIV). Protection against challenge infection and protection against development of simian and feline acquired immunodeficiency syndrome has been achieved in each model by use of inactivated whole virus or virus-cell vaccines. A recombinant SIV envelope peptide vaccine has also proved efficacious. These vaccines have protected against 10-100 animal infectious doses of the homologous cell-free virus given systemically, and, in the simian model, apparently show cross protection against a heterologous strain of SIV. Protected animals appear free of any latent infection although late breakthroughs of infection in a few animals imply that not all vaccinated animals are completely protected. The mechanism of protection in the simian model apparently involves envelope antibody but the role of neutralizing antibody remains unclear. Questions remaining to be answered in both SIV and FIV models are: (1) the duration of immunity, (2) the extent of protection against heterologous strains and mucosal infection, (3) protection against infection with cell-associated virus and (4) the role, if any, of cellular immunity in vaccine protection. Initial attempts at post-infection immunotherapy with SIV vaccines have not yet been successful. The inactivated whole SIV and FIV vaccines offer a promising start and provide hope that a prophylactic AIDS vaccine will be developed. Use of these animal models for antiviral therapy is just now getting underway. Both models should prove especially useful for studies of prophylaxis and therapy, especially during the early stages of infection and for investigations on drug pharmacokinetics or toxicity that can not be done as well in HIV-infected humans. The animals will also be ideal for testing the pathogenicity of drug-induced mutant forms of SIV and FIV. For these purposes it will be necessary to create self-sustaining specific pathogen-free macaque and cat breeding colonies and provide increased housing facilities for infected animals. The future of AIDS research is crucially dependent on the long term availability of these animal models.
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PMID:Simian and feline immunodeficiency viruses: animal lentivirus models for evaluation of AIDS vaccines and antiviral agents. 165 10

Human herpesvirus-6 (HHV-6) was first isolated in 1986 from peripheral blood leukocytes of patients with lymphoproliferative disorders. Although HHV-6 is distinct from the other human herpes viruses, DNA studies have revealed some genomic similarities with cytomegalovirus. It has recently become evident that up to 95% of older children and adults are HHV-6 seropositive. Infection is believed to occur early in life, after maternal antibody has waned. Up to 92% of healthy adults shed HHV-6 in saliva, and evidence indicates that this secretion is important in spread of the virus. In situ hybridization and immunochemical studies suggest that the salivary glands themselves may be the site of replication and persistence of HHV-6. There is good evidence that HHV-6 is causally linked to exanthema subitum, a common febrile disease of infants. Associations of HHV-6 with postviral fatigue syndrome, lymphoproliferative disorders and progression of AIDS have all been examined, but the evidence in these cases remains conflicting.
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PMID:Human herpesvirus-6: the latest human herpes virus. 166 30

A simian type D retrovirus designated SRV induces a fatal immunosuppressive disease in rhesus macaques. This syndrome shows many clinical similarities to acquired immunodeficiency syndrome (AIDS) in human immunodeficiency virus-infected individuals. To investigate the mechanisms of immune dysfunction in SRV infection, we have focused on the interactions of SRV serotype 1 (SRV-1) with macaque B-lymphoblastoid cell lines (B-LCL). Procedures were optimized for establishing B-LCL by immortalization of macaque B lymphocytes with rhesus Epstein-Barr virus (EBV). These cell lines express B-cell surface markers, secrete immunoglobulins of the IgG or IgM isotypes, and release EBV which transforms monkey B cells. In vitro cultures of B-LCL supported replication of SRV-1. Several B-LCL infected with SRV-1 showed downregulation of major histocompatibility complex (MHC) class II antigen expression whereas levels of MHC class I antigen remained unchanged. Infection of B-LCL with SRV-1 did not alter the level of secreted immunoglobulin. Rhesus EBV was also used to obtain B-LCL from macaques infected with SRV-1; these cell lines were found to release infectious SRV-1. Investigations on the interactions of SRV-1 with B cells will be useful for elucidating mechanisms involved in the immunopathogenesis of primate retroviruses.
AIDS Res Hum Retroviruses 1991 Nov
PMID:Characterization of rhesus macaque B-lymphoblastoid cell lines infected with simian type D retrovirus. 166 56

Infection of domestic cats with the feline immunodeficiency virus (FIV) represents an important veterinary health problem and a useful animal model for the development of vaccines against acquired immunodeficiency syndrome (AIDS). Two experimental FIV vaccines have been developed; one consisting of fixed infected cells (Vaccine 1), the other of inactivated whole virus (Vaccine 2). After 4-6 immunizations over 2-5 months, both vaccines induced a strong FIV-specific immune response including neutralizing antibody and T-cell proliferation. Vaccine 1 protected 6 of 9 and Vaccine 2 protected 5 of 6 recipient cats against any detectable infection with a low dose (10 animal ID50) of FIV given intraperitoneally 2 weeks after the final boost. One additional cat in each vaccine group had a transient infection at 5-7 weeks postchallenge following which virus could no longer be detected. Thus, a total of 13 of 15 vaccinated cats were protected against persistent infection. By contrast, 13 of 13 controls were persistently infected by this challenge. The infected cell vaccine failed to protect against a higher dose (5 x 10(4) ID50) of FIV. These results indicate that vaccine prophylaxis against natural FIV infection should be achievable and enhance optimism of the prospect of developing an effective AIDS vaccine for humans.
AIDS Res Hum Retroviruses 1991 Nov
PMID:Experimental vaccine protection against feline immunodeficiency virus. 166 57

Infection with the human immunodeficiency virus (HIV) is a significant and growing problem among intravenous drug users (IVDUs), both from the standpoint of personal morbidity and public health concerns regarding spread of the virus. Most HIV-infected IVDUs are opioid addicts. The most common form of long-term treatment of opioid dependence is methadone maintenance treatment (MMT). MMT can therefore play an important role in both AIDS prevention and reduction of HIV-related morbidity through diminishing drug use, promoting a healthier life-style, and providing direct medical and psychiatric care. Attempts to manage patients with a triple diagnosis of drug abuse, medical, and psychiatric problems can pose significant clinical challenges, requiring the efforts of a multidisciplinary team. The management of HIV-infected patients in MMT is discussed and case examples from the MMT program of the San Francisco General Hospital Substance Abuse Services are presented to illustrate useful strategies in the care of these complicated patients.
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PMID:HIV-infected intravenous drug users in methadone maintenance treatment: clinical problems and their management. 166 16

Natural killer (NK) cells are a discrete subset of leukocytes, distinct from T and B lymphocytes. NK cells mediate spontaneous non-MHC-restricted killing of a wide variety of target cells without prior sensitization and appear to be involved in initial protection against certain viral infections. Depressed NK cell-mediated cytotoxicity, one of the many immunological defects observed in AIDS patients, may contribute to secondary virus infections. Here we report that clonal and purified polyclonal populations of NK cells, which expressed neither surface CD4 nor CD4 mRNA, were susceptible to infection with various isolates of human immunodeficiency virus type 1 (HIV-1). Viral replication was demonstrated by detection of p24 antigen intracellularly and in culture supernatants, by the presence of HIV DNA within infected cells, and by the ability of supernatants derived from HIV-infected NK cells to infect peripheral blood mononuclear cells or CD4+ cell lines. Infection of NK cells was not blocked by anti-CD4 or anti-Fc gamma RIII monoclonal antibodies. NK cells from HIV-infected and uninfected cultures were similar in their ability to lyse three different target cells. Considerable numbers of cells died in HIV-infected NK cell cultures. These results suggest that loss of NK cells in AIDS patients is a direct effect of HIV infection but that reduced NK cell function involves another mechanism. The possibility that NK cells serve as a potential reservoir for HIV-1 must be considered.
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PMID:In vitro infection of natural killer cells with different human immunodeficiency virus type 1 isolates. 167 64

Infection of the T lymphocyte with HIV results in a cytopathic effect and cell death that has been linked to a selective loss of the helper T-lymphocyte function of the immune system. In addition to acute infection, which leads to cell death, a chronic or persistent infection also occurs. The persistence of these viral reservoirs has been implicated in the progression of HIV infection and AIDS. Rational drug discovery targeted to late-stage events in HIV replication has the potential to yield antiviral agents capable of blocking virus spread by inhibiting the production of infectious virions from these chronic reservoirs. Steve Petteway and colleagues discuss antiviral strategies that target the chronically infected cell, with a focus on HIV protease inhibitors.
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PMID:The chronically infected cell as a target for the treatment of HIV infection and AIDS. 167 79

The great majority of individuals with human immunodeficiency virus type 1 (HIV-1) infection presents with no signs or symptoms, or only lymphadenopathy. To initiate prophylactic measures in time it is necessary to establish risk criteria. CD4+ cell counts are significant predictors. Supplementary methods to improve the predictive information of CD4+ cell counts are still required. In addition, CD4+ cell counting is laborious, expensive, and restricted to specialized laboratories. Thus, there is also a place for more easily performed laboratory tests with similar predictive value as CD4+ cell counts. Neopterin and beta 2-microglobulin levels proved to be significant predictors of AIDS risk in HIV-1 seropositives. The predictive value of both parameters is equal to CD4+ cell counts and both markers are significant joint predictors in addition to CD4+ cell counts. Measurement of the parameters is done in serum (neopterin and beta 2-microglobulin) or urine (neopterin) specimens which reduces the risk of HIV-1 transmission compared to handling of whole-blood samples as it is required for cell counting. Although more studies are needed, especially in developing countries and in persons receiving zidovudine, it can be recommended to use neopterin and beta 2-microglobulin as additional marker to estimate AIDS risk in HIV-1 seropositive individuals. Moreover, both markers may be useful for this purpose without CD4+ cell counts if cell counting is not available.
Infection 1991
PMID:Neopterin and beta 2-microglobulin as prognostic indices in human immunodeficiency virus type 1 infection. 167 20

Infection with the human immunodeficiency virus (HIV) results in progressive depletion of the CD4 subset T-lymphocytes and the development of opportunistic infections and certain malignancies. Charts were reviewed for 185 HIV-infected individuals with 265 AIDS-defining illnesses (ADIs) who had T-lymphocyte subset analyses performed within 2 months prior to or 1 month following the diagnosis. Also included were 22 HIV-infected patients with oral candidiasis and 20 with asymptomatic infection. Significant differences in CD4 lymphocyte numbers were observed between the 12 ADIs, oral candidiasis, and asymptomatic infection, allowing them to be grouped into five general categories, based on mean CD4 count: (a) asymptomatic infection, CD4 greater than 500/mm3; (b) oral candidiasis and tuberculosis, range 250-500/mm3; (c) Kaposi's sarcoma, lymphoma, and cryptosporidiosis, range 150-200/mm3; (d) Pneumocystis carinii pneumonitis, disseminated Mycobacterium avium complex, herpes simplex ulceration, toxoplasmosis, cryptococcosis, and esophageal candidiasis, range 75-125/mm3; (e) cytomegalovirus retinitis, less than 50/mm3. Our data concur with clinical impressions and provide a basis for interim treatment and prophylaxis recommendations.
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PMID:Predictive value of CD4 lymphocyte numbers for the development of opportunistic infections and malignancies in HIV-infected persons. 167 19

Chronic diarrhea accompanied by weight loss is a common and often debilitating problem associated with human immunodeficiency virus (HIV) infection. Enterocytozoon bieneusi, a newly identified species of the phylum of protozoa, Microspora, has been reported associated with chronic diarrhea and wasting in 11 acquired immunodeficiency syndrome (AIDS) patients in the United States, Europe, and Africa. Diagnosis has been based solely on the ultrastructural identification of this small, intracellular parasite in bowel biopsies. Seventy-one small bowel biopsies from 67 homosexual AIDS and AIDS-related complex patients with chronic diarrhea and with no pathogens identified by light microscopy on paraffin sections, were embedded in plastic and studied by light and transmission electron microscopy. Enterocytozoon bieneusi microsporidiosis was diagnosed by electron microscopy in 20 (22 biopsies) of the patients. More jejunal biopsies (16 of 36) were positive than duodenal biopsies (six of 35). Parasites and spores were clearly visible at the light microscopic level in the semi-thin plastic sections from 17 and 21 of the biopsies, respectively. In retrospect, parasites could be identified by light microscopy in standard hematoxylin and eosin-stained paraffin sections. Infection was confined to enterocytes covering the villi, especially the tips, and was associated with villous atrophy and cell degeneration, necrosis, and sloughing. Release of spores into the bowel lumen was evident. Colorectal biopsies from two of the patients with small bowel microsporidiosis were negative for microsporidia. Enterocytozoon bieneusi infection of the small bowel may be an important cause of diarrhea in HIV-infected persons.
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PMID:Intestinal microsporidiosis as a cause of diarrhea in human immunodeficiency virus-infected patients: a report of 20 cases. 169 61


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