摘要:

A fatal immunodeficiency syndrome with clinical and pathologic features similar to human AIDS is inducible in cats by experimental inoculation with a specific strain of feline leukemia virus (FeLV) called FeLV-FAIDS. The course of the feline disease is characterized by an age-dependent prodromal period during which a non-disease-specific,commonform of proviral DNA is detected in bone marrow. Preceding clinical onset of immunodeficiency is production of high levels of specific, pathogenic variant genomes, primarily as unintegrated viral DNA, in bone marrow.Acute immunodeficiency syndrome(survival period −3 months) is associated with a short prodromal period and appearance of a characteristic variant genome (variant A) that persists at high copy number as integrated and full-length unintegrated viral DNA in bone marrow.Chronic immunodeficiency syndrome(survival >1 year) is marked by a longer prodromal period, a more gradual onset of severe clinical immuno-suppression, and a predominance of other variant genomes that often contain substantial internal deletions. In both forms of the disease, tissue-specific replication of certain variant viruses is noted in the bone marrow, intestine, and lymph nodes. Evidence from in vitro and in vivo virus transmission studies indicates that the appearance of FeLV-FAIDS variant viruses reflects differential replication of viral genomes pre-existing in the inoculum rather than rapid de novo evolution of new variants within each animal. These results demonstrate that retrovirus-induced immunodeficiency disease in cats can be associated with and prefigured by the amplified replication of specific viral variants in target tissues.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The human immunodeficiency virus type 1 (HIV-1) Rev protein is a positive posttranscriptional regulator of viral structural gene expression and essential for virus replication. Rev mediates its effects through interaction with an RNA target sequence, the Rev responsive element (RRE), present within theenvmRNA. Previous studies have shown that the basic stretch of amino acids are required for Rev's ability to bind RNA, whereas residues present near the carboxy terminus are essential for full biological activity. Deletion mutagenesis was used to define the minimal domain required for RNA binding and function. We found that amino acids 8 through 67 confer full binding activity, whereas full biological activity requires the presence of residues 8 through 83. The minimal RNA binding sequence of HIV-1 Rev also interacts and functions with the HIV-2 and SIV RRE elements, indicating that the same domain is responsible for the biological activity with different, but related viruses. Mutational analysis of the RRE was also carried out in an effort to further define elements crucial for its function. Our findings indicate that interaction with Rev involves a stretch of three G nucleotides present at the base of a stem loop structure previously shown to be critical for Rev binding. These results suggest that the high degree of secondary structure of the RRE RNA may serve as a guide to bring Rev in contact with a primary nucleotide sequence required for stable protein-RNA association.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Recombinant adenovirus vectors expressing the entiregag(p55) or CA (p24) region of human immunodeficiency virus type 1 (HIV-1) were constructed by inserting the appropriate HIV DNA sequences into the E3 region of human adenovirus type 5 (Ad5) with and without an exogenous SV40 early promoter. The infectious recombinant adenovirusesAdgagl, AdSVgag1, and AdSVCA1 were shown to express the appropriate HIV-1 antigens in human cells in vitro, as measured by immunoprecipitation and p24 antigen capture assays. Using the p24 antigen capture assay, HIV antigen expressed by AdSVCA1 was detected earlier in infection and in greater amounts than that produced by either Adgag1 or Adgag1. In studies concerning the immuno-genicity of these vectors, Balb/c (H-2d) mice given a single intraperitoneal injection of 107or 108plaque-forming units of purified vector developed serum antibodies to p24, detected by Western blotting, by 2 weeks postinjection. In the preliminary test of the immunogenicity of the recombinant adenovirus vectors in primates, two of four rhesus macaque monkeys generated antibodies to HIV-1 p24 following two injections of AdSVCA1. As expected, monkeys injected with control adenovirus failed to show any anti-HIV response, and none of the monkeys showed any adverse reactions following infection with either recombinant or control adenoviruses. These results suggest that adeno-Virus vectors have considerable potential in the study of possible immune therapies for HIV infection.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Human immunodeficiency virus (HIV) infection is characterized by a progressive impairment in immunocompetence leading to severe opportunistic infections and malignancies. In a double-blind, placebo-controlled study, the potential impact of immunomodulation by oral ranitidine, 600 mg daily, for 28 days was studied in 18 HIV-positive patients (CDC group II). All were without clinical signs of infections and were not treated with other known immunomodulating agents. Several immunological parameters related to HIV infection were studied and confirmed to be impaired early in HIV infection. Spontaneous and in vitro interleukin-2− and interferon-α-stimulated natural killer cell activity improved in the ranitidine-treated patients in contrast to a decrease in nontreated patients (#p < 0.03, #p < 0.01, #p < 0.02 between groups, respectively). Furthermore, T-cell blastogenesis to phytohemagglutinin stimulation and soluble interleukin-2 receptors in serum increased in ranitidine-treated patients compared with nontreated patients (#p < 0.01). However, ranitidine treatment did not change CD4+cell counts. Although the significant improvement in immunocompetence shown in this study is small, the present result indicates the need for further trials with immunomodulation by ranitidine in HIV-infected individuals.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The ventricular area at the level of the foramen of Monro was measured from axial x-ray computed tomography (CT) scans obtained prior to and 6 months after the initiation of continuous infusion of zidovudine (ZDV) in eight children with human immunodeficiency virus-induced encephalopathy. Evidence of moderate to severe central atrophy was present on initial CT scans (p< 0.05). Ventricular area and ventricular brain area ratio (VBR) decreased after ZDV therapy in seven of eight children (mean decrease of 21.5 and 20%, respectively,p< 0.05). The degree of decrease in VBR correlated with reductions in cerebrospinal fluid (CSF) protein concentration (r= 0.93,p< 0.01), but not lymphocyte T4 or T8 counts. Intelligence quotients (IQs) improved in all seven children tested (mean improvement of 17.7%,p< 0.01) and correlated significantly with reductions in CSF protein concentration (r= −0.85,p= 0.003). The magnitude of IQ changes was not significantly correlated with the magnitude of changes in ventricular area. We conclude that the cognitive improvement of HIV encephalopathy seen after 6 months of continuous infusion of ZDV is accompanied by reduction in brain atrophy and decreased CSF protein, suggesting an ameliorating effect of ZDV on the pathogenesis of AIDS encephalopathy in children.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The pathophysiology of anemia in patients with human immunodeficiency virus (HIV) infection is multifactorial. In order to determine the role of erythropoietin (EPO) response as a cause of the anemia, serum levels were determined by direct radioimmunoassay in 110 symptomatic patients with various stages of HIV infection. Symptomatic patients (ARC and AIDS) not receiving zidovudine (ZDV) therapy demonstrated a strong inverse relationship between serum EPO and hemoglobin levels (p= 0.01 andp< 0.001, respectively). Patients with AIDS who were anemic while receiving ZDV demonstrated serum EPO levels that ranged from normal to markedly elevated (93,390 mU/ml). The diversity of serum EPO levels in patients with HIV infection and anemia suggests that the etiology of anemia in these patients and their potential response to recombinant human EPO may not be uniform.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The incidence and characteristics of campylobacteriosis among patients with acquired immune deficiency syndrome (AIDS) in Los Angeles County were assessed by matching theCampylobacterand AIDS surveillance reporting registries for the years 1983–1987.Campylobacterinfection was reported in 29 (0.7%) of 4,433 AIDS cases. The average annual incidence ofCampylobacteramong AIDS cases (519/100,000) exceeded the crude population rate by 39-fold and exceeded the rate among males aged 15–55 years by 35-fold.Campylobacterinfection was more common in female AIDS patients than male patients (p= 0.065). A distinct seasonal variation was noted with peaks occurring in July and November. The median survival time for AIDS patients withCampylobacter(14 months) was lower than that for AIDS patients withoutCampylobacter(21 months); however, we were not able to assess potential confounders such as subsequent opportunistic infections or antiviral therapy and prophylactic regiment to validate this finding.Campylobactercases with AIDS had higher rates of bacteremia and hospitalization thanCampylobactercases without AIDS. Attempts should be made to elucidate the sources ofCampylobacterand other enteric infections among AIDS patients.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Two cases of invasive aspergillosis in AIDS patients are reported and previously reported AIDS-related cases are reviewed. Only one-half of all cases were diagnosed antemortem. Outcome is poor despite antifungal and surgical therapy. Normal phagocytic function is important in host defense againstAspergillusspecies. HIV-infected patients may have impaired phagocytic function as a result of antiretroviral therapy or treatment of opportunistic infection, or due to HIV infection itself. As the lifespans of HIV-infected patients are extended by antiretroviral therapy, an increasing awareness ofAspergillusinfection as an opportunistic pathogen will be necessary.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

A cross-sectional study was carried out in October 1988 among clients of public health centers in Italy that provide assistance for drug dependency. In addition to estimating the frequency of HIV-1 infection and of risk factors related to drug use, the study estimated the temporal gap between relevant events in the drug history of each subject. Forty-eight centers participated, representing 16 of the 20 Italian regions. Among 1,038/1,348 subjects, 395 (38%) were carriers of HIV-1 antibodies. Seropositivity was related to the length of heroin use (with the risk of being seropositive increasing by 1% for each month of use), to frequency of sharing injection equipment, and to sexual intercourse with a seropositive partner. Women were more likely to have shared injection equipment and to have engaged in sexual intercourse with seropositive partners. Most subjects began sharing injection equipment within a year of initiating drug use, and the median temporal gap between first drug use and first visit to a drug dependency center was 5 years. A high proportion of both seropositive (87%) and seronegative (74%) subjects reported the adoption of safer drug-use practices. In both groups many behavioral changes (38%) were reported to have been introduced before the initial HIV test. These findings confirm that efforts to reduce HIV infection among drug users in Italy will need to concentrate both on prevention of drug use and on early intervention to reduce high-risk behaviors.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

We report on the epidemiology of sexual behaviors, HIV-1 sero-prevalence, and condom use in gay and bisexual men in six Mexican cities in 1998 and test the extent to which variations in sexual behavior and sociological risks are responsible for variations in prevalence. Seroprevalence rates among samples in six cities ranged from 2% to 25%. In multiple logistic regression models controlling for city, insertive/receptive behavior (IRB), and meeting partners in bathhouses, the following were independently related to scropositivity (p < 0.05): city, IRB, syphilis, sex with a person with AIDS, and meeting partners in bathhouses. The independent risks associated with categories of IRB were no or almost no activity (odds ratio 1.0), only insertive (3.0), mostly insertive (4.9), mixed (6.0), mostly receptive (3.3), and only receptive (0.9). The condom use rate on last sexual encounter was 30%. The main sexual risk for HIV-1 infection is not exclusively receptive anal sex, but rather mixed behavior. This association may be explained by the infectious state of the partner pools. The sociologic risk variables (national and local partner pools) are better predictors of seroprevalence than behavioral variables, such as the number of partners or use of condoms. These results imply that more effective individual strategies for risk reduction are needed, including better knowledge concerning the risk status of partners.

ISSN:0894-9255    

出版商:OVID    

年代:1991

数据来源: OVID