Incompletely reverse-transcribed human immunodeficiency virus type 1 genomes in quiescent cells can function as intermediates in the retroviral life cycle.

Using a quantitative polymerase chain reaction (PCR) method, we have previously shown that a molecularly cloned isolate of human immunodeficiency virus type 1 (HIV-1) can efficiently enter quiescent primary lymphocytes; however, the reverse transcription process is not completed in these cells. In this study, we further characterized the reverse transcription of HIV-1 in quiescent cells, and our results indicate that while initiation of reverse transcription occurs simultaneously in both activated and quiescent lymphocytes, it not only ends prematurely but also proceeds more slowly in quiescent cells. We also performed experiments to address the role of partial reverse transcripts as intermediates in the viral life cycle.

The region of the envelope gene of human immunodeficiency virus type 1 responsible for determination of cell tropism.

Different isolates of human immunodeficiency virus type 1 (HIV-1) vary in the cell tropisms they display, i.e., the range of cell types in which they are able to establish a productive infection.

Increased susceptibility of differentiated mononuclear phagocytes to productive infection with human immunodeficiency virus-1 (HIV-1).

Differences in susceptibility to infection of most mononuclear phagocytes with HIV-1 are not known. We investigated the relative susceptibility of autologous freshly isolated blood monocytes (MN), MN cultured in vitro to allow differentiation (CM), and alveolar macrophages (AM) from healthy subjects to productive infection with HIV-1. Cells were infected with the macrophage tropic strain HIV-1JR-FL and p24 gag antigen levels measured in supernatants by ELISA.

[Pneumothorax in cystic fibrosis: intrapleural instillation of Atabrine].

Intrapleural instillation of quinacrine HC1 (Atabrine) was used to treat spontaneous pneumothorax in 2 young men, aged 26 and 36 years, respectively, with advanced pulmonary disease due to cystic fibrosis. Pneumothorax did not recur until 1 year later in 1 case and 2 years later in the other. This mode of therapy for pneumothorax provides a valuable alternative to surgery for the patient with cystic fibrosis, severe lung disease and marginal pulmonary reserve.

HIV-1 tropism for mononuclear phagocytes can be determined by regions of gp120 outside the CD4-binding domain.

Cells of the mononuclear phagocyte system are the predominant cell producing HIV-1 in most tissues including the central nervous system (CNS), spinal cord, lung and skin; infection is associated with dementia, neuropathy, pneumonitis, and dermatitis respectively. Different HIV-1 isolates vary markedly in their ability to infect mononuclear phagocytes productively. Here we describe molecular clones of a CNS-derived isolate, HIV-1(JR-FL), which can replicate efficiently in mononuclear phagocytes.

Human immunodeficiency virus type 1 T-cell tropism is determined by events prior to provirus formation.

Different strains of human immunodeficiency virus type 1 (HIV-1) vary in the ability to replicate in cells that bear the HIV-1 receptor, CD4. The mechanism responsible for these cell tropism differences is unknown. We examined different isolates of HIV-1 with regard to replication in specific tumor-derived CD4-positive T-cell lines and normal peripheral blood lymphocytes.

Characterization and expression of novel singly spliced RNA species of human immunodeficiency virus type 1.

Human immunodeficiency virus type 1 (HIV-1) expresses the Vif, Vpr, Vpu, and Env proteins through complex differential splicing of a single full-length RNA precursor. We used HIV-1-specific oligonucleotide primer pairs in a quantitative polymerase chain reaction procedure on RNA from fresh peripheral blood lymphocytes infected with HIV-1JR-CSF to detect and characterize the singly spliced RNA species which might encode these proteins. The nucleotide sequences at the junctions of splice donor and acceptor sites of these RNAs were determined.

HIV-1 entry into quiescent primary lymphocytes: molecular analysis reveals a labile, latent viral structure.

Productive infection of human T lymphocytes by HIV-1 is dependent upon proliferation of the infected cell. Nonproliferating quiescent T cells can be infected by HIV-1 and harbor the virus in an inactive state until subsequent mitogenic stimulation. We use a modification of the polymerase chain reaction method, which is both sensitive and quantitative, to demonstrate that HIV-1 DNA synthesis is initiated in infected quiescent T cells at levels comparable with those of activated T cells.

Recent advances in detection of human T-cell leukemia viruses type I and type II infection.

The human T-cell leukemia viruses type I (HTLV-I) and type II (HTLV-II) have been implicated in the pathogenesis of a variety of neoplastic and neurological disorders. Classical techniques for detection involve assay of serum for antibodies by Western blotting or ELISA, which do not discriminate between infection with HTLV-I and HTLV-II. In order to provide appropriate prognostic information to infected individuals and to obtain an accurate assessment of the prevalence of both retroviruses in the United States, we and others have applied the technique of enzymatic DNA amplification to detect HTLV-I and HTLV-II.

High rate of HTLV-II infection in seropositive i.v. drug abusers in New Orleans.

Confirmed infection with HTLV-II (human T cell leukemia virus type II) has been described only in rare cases. The major limitation to serological diagnosis of HTLV-II has been the difficulty of distinguishing HTLV-II from HTLV-I (human T cell leukemia virus type I) infection, because of substantial cross-reactivity between the viruses. A sensitive modification of the polymerase chain reaction method was used to provide unambiguous molecular evidence that a significant proportion of intravenous drug abusers are infected with HTLV, and the majority of these individuals are infected with HTLV-II rather than HTLV-I.

HIV-1 production from infected peripheral blood T cells after HTLV-I induced mitogenic stimulation.

The human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type I (HTLV-I) are two distinct human retroviruses that infect T cells. Recent epidemiologic studies have identified a cohort of individuals that are coinfected with both viruses. It is reported here that human peripheral blood leukocytes infected with HIV-1 in vitro can be induced to produce large quantities of HIV-1 after mitogenic stimulation by noninfectious HTLV-I virions.

Characterization of a leukemia-derived transforming growth factor.

A novel transforming growth factor activity has been identified in the serum-free medium derived from cultures of SMS-SB cells, a human pre-B acute lymphoblastic leukemia cell line. This activity (leukemia-derived transforming growth factor) was biochemically distinct from known fibroblast mitogens such as epidermal growth factor, transforming growth factor alpha, transforming growth factor beta, platelet-derived growth factor, and the endothelial cell growth factor/fibroblast growth factor family of mitogens. Leukemia-derived transforming growth factor was heterogeneous on heparin affinity chromatography, fractionating into three peaks of activity.

Transforming gene of a human leukaemia cell is unrelated to the expressed tumour virus related gene of the cell.

The virally encoded oncogenes (v-onc) of avian and mammalian retroviruses are the recombinant products of normal cellular genes (c-onc) and a retroviral genome. These cellular homologues have been highly conserved during evolution and are found in human DNA. The expression of at least one c-onc under the control of a viral promoter results in transformation of cells in a manner resembling that displayed by the v-onc counterpart; the inappropriate expression of c-onc in the absence of viral influences could likewise result in the malignant state.

The mortality experience of workers exposed to tetrachlorodibenzodioxin in a trichlorophenol process accident.

A standardized mortality analysis was conducted on workers exposed to tetrachlorodibenzodioxin in a trichlorophenol process accident at the Monsanto Company plant in Nitro, West Virginia. One hundred and twenty-one workers who developed chloracne resulting from this accident on March 8, 1949, were selected for study. Follow-up of this group was 100% complete.

The alienation of youth.

The family physician can play a crucial role in youth counselling, if he is willing to meet youth on its own grounds. This paper presents a study of dissociated adolescents between the ages of 14 and 20, seen from 1960 to 1969. Parents were encouraged to attend-the key to an improved functioning youth is to be found in improved family function.