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Biomedical subjects

B Conway

Publications and source records attributed to B Conway.

At least 73 records · Page 4Linked to original sources
PubMed1994

High frequency of Gag- and envelope-specific cytotoxic T lymphocyte precursors in children with vertically acquired human immunodeficiency virus type 1 infection.

Circulating human immunodeficiency virus type 1 (HIV-1)-specific cytotoxic T lymphocytes (CTL) are seen less frequently in unstimulated peripheral blood mononuclear cells (PBMC) from children with vertically acquired HIV infection than in PBMC from HIV-infected adults. HIV-1 Gag-, reverse transcriptase (RT)-, and envelope (Env)-specific cytotoxic activity was studied in PBMC from HIV-infected children. Only 9% of subjects had Gag- or RT-specific CTL in unstimulated PBMC. However, in PBMC studied after CD3 stimulation, Gag- and Env-specific CTL were found in PBMC from 91% and 78% of HIV-infected children, respectively. Limiting dilution analysis of precursor CTL (pCTL) frequencies in PBMC from children > 12 months old demonstrated Gag- and Env-specific pCTL frequencies from 0.5 to 6.3/10,000 PBMC and from 0.66 to 33.0/10,000 PBMC, respectively. Thus, children with vertically acquired HIV infection have high frequencies of HIV-specific pCTL.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The impact of pain and impaired role performance on distress in persons with cancer.

The observed upward trend in the incidence of many cancers is expected to continue for the next 20 years despite monumental basic research efforts. There are interpersonal and intrapsychic complications associated with cancer and its treatment leading to considerable distress which, in extreme cases, becomes clinical depression and anxiety. Pain and impaired role performance have been cited as being important sources of distress in people with cancer. This paper presents data from a community sample of 1,309 people living with cancer in Prince Edward Island, Manitoba and Quebec and examines risk factors for cancer-related distress. In the model tested in this paper, pain and other symptoms and treatment side-effects as well as cancer-related fears were seen to have direct and indirect effects on psychological symptoms of distress. Impaired role performance was a central mediator for the indirect effects. The model explained 34% of the variance in distress scores (General Health Questionnaire) and was equally applicable to all three study sites, both male and female subjects, rural and urban settings, and to all stages of illness. Pain was the single most important explanatory variable. Impaired role performance had a negative effect on distress over and above the effect of pain. The results suggest that interventions directed at reducing distress in cancer should also address interpersonal issues such as the impact of the illness on family, social network a work.

Adaptation, Psychological↗
PubMed1992

Eosinophils as host cells for HIV-1.

Transient expression of HIV-1 p24 antigen was observed in eosinophils acutely infected with the HTLV-IIIB strain of HIV-1. PCR analysis of eosinophils isolated from 18 seropositive individuals showed HIV-1 sequences to be present in 2 subjects. These data suggest that eosinophils may act as host cells for HIV-1.

DNA, Viral↗
PubMed1992

Comparison of spot-blot and microtitre plate methods for the detection of HIV-1 PCR products.

We have compared spot-blot methodology with a recently developed rapid microtitre plate assay for the specific detection of HIV-1 PCR products. We have studied blood specimens isolated from HIV-1 infected individuals (48 asymptomatic and 56 symptomatic patients). Mononuclear cells were isolated, lysed and processed for PCR. Both PCR product detection methods were carried out in parallel on all amplified samples. HIV-1 sequences were detected by spot-blot or microtitre plate hybridization in samples taken from 42/48 asymptomatic and 53/56 symptomatic subjects. Concordant results between the two detection methods were observed for 90 samples, with 81 positive and nine negative assays. On repeat evaluation of the 14 discordant samples, nine showed concordant positive results, near the limit of detection of the assay. Serial dilutions of ACH-2 cells were amplified, and the PCR products were detected using the microtitre plate assay, yielding semi-quantitative results. The sensitivity of this simple, rapid assay compares with that of more laborious DNA detection systems. This may become a useful tool in HIV-1 research and in the clinical care of seropositive individuals.

DNA, Viral↗
PubMed1992

Human immunodeficiency virus type 1 envelope gene structure and diversity in vivo and after cocultivation in vitro.

Nested-primer polymerase chain reaction (PCR) has been applied to the molecular cloning of 4.6-kb half-genome fragments of human immunodeficiency virus type 1 (HIV-1) taken directly from the peripheral blood mononuclear cells (PBMC) of an individual with neurological symptoms of HIV-1 infection. In a similar manner, gp120-coding portions of the envelope gene were cloned after PBMC from the same blood sample were cocultivated with uninfected PBMC for 28 days. The complete 1.6-kb nucleotide sequence of the gp120 gene was determined from each of 35 clones examined. Two of 13 (15%) PBMC-derived gp120 genes and 3 of 22 (14%) coculture-derived gp120 genes were defective as a result of frameshifts and an in-frame stop codon(s). Mean diversity between individual gp120-coding sequences in PBMC was fivefold greater (3.24%) than after coculture (0.65%). A predominant sequence of "strain" was found after coculture that was distinct from the diverse viral genotypes detected in vivo and therefore was selectively amplified during in vitro propagation. Multiple distinct third variable (V3) regions encoding the principal neutralizing domain of the envelope protein were detected in PBMC-derived genes, suggesting the presence of immunologic diversity of HIV env genes in vivo not reflected in the cocultured virus sample. The large size of the HIV fragments generated in this study will permit analysis of the diversity of immunologic reactivity, gene function, and pathogenicity of HIV genomes present within infected individuals, including the functional significance of the loss of diversity that occurs upon coculture.

Acquired Immunodeficiency Syndrome↗
PubMed1990

The value of single-dose therapy to diagnose the site of urinary infection.

Several single dose regimens have been shown to cure 90 percent of women with acute cystitis in whom infection is confined to the bladder. About 25 percent of women with acute cystitis and approximately one-half with asymptomatic infection have organisms originating from one or both upper urinary tracts. Effective single dose regimens such as trimethoprim-sulfamethoxazole, amoxicillin, and trimethoprim alone, cure between 40 and 60 percent of upper tract infections in women with renal involvement, who present with acute cystitis or with asymptomatic bacteriuria. Five studies have shown that single dose failure in women with acute cystitis or asymptomatic bacteriuria is a specific predictor of upper tract infection. It is also sensitive (60-80 percent) in predicting upper tract pathology. The evidence to date favours the hypothesis that failure of single dose cure following treatment with an effective single dose regimen in adult women who have asymptomatic bacteriuria or acute cystitis, identifies a subset of women who require further investigation of the urinary tract.

Anti-Infective Agents, Urinary↗
PubMed1990

Detection of HIV-1 DNA in crude cell lysates of peripheral blood mononuclear cells by the polymerase chain reaction and nonradioactive oligonucleotide probes.

The aim of this study was to detect HIV-1 proviral DNA in lysates of peripheral blood mononuclear cells (PBMCs) by the polymerase chain reaction (PCR) and hybridization with a nonradioactive probe. PBMCs were lysed in 1% Triton X-100. PCR was then carried out using primers complementary to a conserved region of the HIV-1 pol gene. Bracket and nested amplification protocols were used. Products were identified by dot-blot hybridization or agarose gel electrophoresis and Southern hybridization, using an alkaline phosphatase-linked oligonucleotide probe specific for amplified sequences. Colorimetric and chemiluminescent substrates were used. HIV-1 DNA was detected in PBMCs of 57/59 HIV-1-seropositive individuals, 8 of which were positive only following the use of nested primers. Of 12 seropositive samples that were negative by other HIV-1 diagnostic tests (PBMC coculture and serum p24 antigen detection), 11 were positive by PCR. PCR using PBMC lysates is a very sensitive method of detecting HIV-1 proviral sequences. The use of nested primers appears to increase the sensitivity of the procedure.

Base Sequence↗
PubMed1988

An overview of some mechanisms of bacterial pathogenesis.

The adherence of microorganisms to host surfaces is highly specific, and in many cases, essential for subsequent pathogenetic events to occur. A dynamic process leading to increased mucosal adherence of gram-negative bacilli to epithelial cell receptors in the oral cavity appears to be the initial step in the development of pneumonia. In infectious processes secondary to Streptococcus pneumoniae, adherence may also play a role in specific syndromes. In many cases, however, colonization of oropharyngeal mucus itself, the presence of capsular polysaccharide, and the release of various cell wall components appear to interact to cause clinical disease. In Neisseria gonorrhoeae infections, adherence is all important and is mediated by a number of cell surface structures. These have been studied extensively. Many of these structures, such as pili and protein II, exhibit great variability both between strains and in the same organism at different stages of infection. Others, such as protein I, are more constant. This information has been used in the production of specific vaccines to more preserved structures to inhibit adherence. These will be tested in the near future. It is our view that a better understanding of the many forms of bacterial adherence will be the key to our designing more effective strategies to detect early infection and to intervene more decisively to limit its spread.

Bacteria↗
PubMed1988

Seroprevalence and demographic information of patients at risk for human immunodeficiency virus (HIV) infection in Manitoba, Canada.

Two hundred fifty individuals from high risk categories were enrolled in a seroprevalence survey for human immunodeficiency virus (HIV) infections in Winnipeg. The overall seroprevalence in the Manitoba AIDS Virus Epidemiology Study (MAVES) was 5.2%. Of 2651 diagnostic and screening specimens in the province of Manitoba submitted over a similar period, 103 were positive (3.9%). HIV seropositivity in Manitoba was noted mainly in homosexual/bisexual males (especially those who were also intravenous drug abusers), hemophiliacs, and individuals from endemic regions of the world. Individuals whose only risk factor was intravenous drug abuse, those with sexually transmitted diseases, or those with high risk sex contacts have not demonstrated HIV seropositivity in Manitoba to date. Manitoba is currently a low seroprevalence region for HIV infection. Our study demonstrated that the awareness level of people at risk for HIV infections was low. In our study population, one-on-one counseling was demonstrated to be an effective way to improve short-term knowledge about HIV infections. Appropriate education approaches must be considered for Native/Metis peoples (26.4% of our MAVES study population), who were younger and had a lower educational and employment level compared to Caucasian/other racial groups.

Acquired Immunodeficiency Syndrome↗