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Biomedical subjects

J R Carlson

Publications and source records attributed to J R Carlson.

At least 91 records · Page 5Linked to original sources
PubMed1988

Enzyme immunoassay for the detection of Giardia lamblia.

An enzyme immunoassay (EIA) was developed for direct detection of Giardia lamblia antigens in fecal specimens. The EIA was evaluated by testing specimens from 1,331 subjects in the USA and Egypt. For the 353 specimens from human subjects in the USA there was a 97% overall agreement between the results of the EIA and direct microscopic examination, yielding a sensitivity and specificity of 92% and 99% respectively. Due to adverse field conditions the EIA did not perform as well in the specimens collected and tested in Egypt. The sensitivity and specificity for 585 human specimens from Egypt were 74% and 97% respectively.

Animals↗
PubMed1988

A new means of inducibly inactivating a cellular protein.

This paper presents a general means of eliminating the function of a single protein without relying on genetic alterations in its structure or level of synthesis. The strategy is based on the inducible cellular expression of neutralizing antibody to inactivate the protein selectively. The feasibility of this approach is illustrated by using alcohol dehydrogenase I (ADH I) in Saccharomyces cerevisiae as a model. Heavy- and light-chain cDNAs were isolated from a hybridoma secreting an antibody which neutralizes yeast ADH I. The cDNAs were characterized with respect to their length and identity, their signal sequences were removed, and synthetic translation initiation codons were joined to them. These truncated sequences were then inserted into an inducible expression vector and shown to be expressed as stable heavy and light chains, which assemble and bind antigen. The sequences were introduced into yeast mutants containing different levels of ADH activity, and evidence is provided that the antibodies produce limited neutralization of enzyme activity in vivo. In principle, the approach can be used for any cell type in which functional antibody can be inducibly expressed.

Alcohol Dehydrogenase↗
PubMed1988

Molecular tools for inactivating a yeast enzyme in vivo.

As part of an effort to develop a new means of inducibly inactivating cellular proteins in vivo, three monoclonal antibodies which neutralize yeast alcohol dehydrogenase (ADH) activity were isolated and characterized with respect to criteria important for the inactivation strategy. The significance of these criteria is considered, and a general means of generating appropriate antibodies is suggested. All three antibodies described here were specific for ADH I; they did not recognize the closely related isozyme ADH II in a plate-binding assay and did not immunoprecipitate molecules other than ADH from a Saccharomyces cerevisiae extract. Neutralization occurred in a yeast extract and, for two antibodies, was blocked by high concentrations of the coenzyme NAD+. This finding suggests that the antibodies may block enzyme activity by stabilizing an inactive form of ADH lacking bound NAD+. These results provide a foundation for the use of these antibodies to inactivate ADH in vivo.

Alcohol Dehydrogenase↗
PubMed1988

In situ detection of human immunodeficiency virus (HIV) nucleic acid in H9 cells using nonradioactive DNA probes and an image cytophotometry system.

Rapid and sensitive nonradioactive methods to detect human immunodeficiency virus (HIV)-infected cells are needed in clinical medicine. We developed an in situ hybridization test using 2-acetylaminofluorene (AAF)-labeled HIV DNA as a hybridization probe. Hybridized probe was detected using rabbit anti-AAF antibody, followed by alkaline phosphatase-conjugated goat anti-rabbit, and the bromochloroindolyl phosphate-nitroblue tetrazolium reaction. An image cytophotometry system was used to quantitate the percentage of HIV-infected cells. These methods were used to determine the percentage of H9 cells infected with HIV. HIV was detected in 0% of cells on day 1 post infection, 7% on day 4, 41% on day 8, and 5% on day 15. These results paralleled those of the reverse transcriptase assay and an antigen capture ELISA assay for HIV antigen. Thus the AAF modified HIV DNA probe detected HIV nucleic acid in infected H9 cells and the image cytophotometry system improved the sensitivity and objectivity of detection.

2-Acetylaminofluorene↗
PubMed1988

Interrelations of lymphocyte subset values, human immunodeficiency virus antibodies, and HIV antigen levels of homosexual males in San Francisco.

Serum and leukocytes from a cohort of homosexual males were analyzed to determine the interrelationships of antibodies to human immunodeficiency virus (HIV), serum HIV antigen levels, and phenotypical differences in lymphocyte subpopulations of HIV antibody-positive (HIV Ab+) and HIV antibody-negative (HIV Ab-) homosexual males. Significant reductions were observed in the percentages of B lymphocytes, CD4+ and CD4+ kappa lambda- T lymphocytes and the CD4+/CD8+ ratios of HIV Ab+ homosexual males in comparison to HIV Ab- homosexual males. Significant increases were observed in the percentages of CD8+, CD8+ CD11b-, CD8+ kappa lambda-, CD8+ DR+, CD8+Leu7+, and Leu7+ lymphocytes of HIV Ab+ study subjects. Statistical analysis revealed that among the immunological variables tested, decreases in the CD4+/CD8+ ratio and in the percentage of CD4+ kappa lambda- lymphocytes showed the strongest associations with HIV-sero-positivity in asymptomatic homosexual males. Only 44 (16.5%) of 267 HIV Ab+ homosexual males had detectable levels of HIV antigen (HIV Ag) in their serum. The percentages of CD4+ or CD4+ kappa lambda- lymphocytes and the CD4+/CD8+ ratios of HIV Ab+ males differed significantly between HIV Ag-positive (HIV Ag+) and--negative (HIV Ag-) homosexual males. These variables, however, did not correlate well with HIV Ag levels,indicating that no clear associations can be drawn between levels of HIV antigen and lymphocyte subset abnormalities of HIV-infected individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Clearance of Giardia muris infection requires helper/inducer T lymphocytes.

The aim of this work was to identify the T cell subset (helper/inducer or cytotoxic/suppressor) that plays a major part in the clearance of Giardia muris infection. BALB/c mice were selectively depleted of helper/inducer (Th/i) or cytotoxic/suppressor (Tc/s) T cells, by treatment with rat IgG monoclonal antibodies directed against the Th/i cell surface antigen L3T4, or against the Tc/s cell surface antigen Ly-2, and were infected with G. muris cysts. While mice depleted of Tc/s cells cleared G. muris infection at a normal rate, mice depleted of Th/i cells did not clear the infection. Depletion of the relevant T cell subset was confirmed by flow cytometry and by immunohistochemistry. The data indicate that helper/inducer T cells, but not cytotoxic T cells, are of major importance for elimination of G. muris from the mouse intestine.

Animals↗
PubMed1987

Rapid, easy, and economical screening test for antibodies to human immunodeficiency virus.

A new dot enzyme immunoassay (EIA) with a conserved portion of the envelope protein of the human immunodeficiency virus (HIV) as antigen has been designed for use in areas with few laboratory facilities and by personnel with little laboratory experience. Sera were tested in 263 subjects who had AIDS or AIDS-related complex or were at-risk or not-at-risk of AIDS from the USA, Africa, and Asia/Oceania. The dot EIA was 100% sensitive in the American subjects, and there were only 2 false negatives in the others, both of which were negative by commercial EIA. The test is simple to perform, economical, rapid (30 min), and stable.

Antibodies, Viral↗
PubMed1987

Risk of transmitting the human immunodeficiency virus, cytomegalovirus, and hepatitis B virus to health care workers exposed to patients with AIDS and AIDS-related conditions.

This prospective cohort study was designed to evaluate the risk of occupational transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and cytomegalovirus (CMV) to health care workers with intensive exposure to HIV-infected patients. Seventy-five percent of the 270 subjects had been exposed to patients with AIDS and AIDS-related conditions (ARC) for at least one year before enrollment, 18% worked in specialized AIDS units, and 35% sustained a total of 342 accidental parenteral exposures to HIV-infected body fluids. At the time of enrollment, none had antibody to HIV, and none of the 175 subjects retested 10 months later had acquired antibody. No evidence of increased risk of acquiring CMV or HBV was obtained. These results indicate that health care workers are at minimal risk for HIV, CMV, and HBV transmission from occupational exposure to patients with AIDS or ARC, even when intensively exposed for prolonged periods of time.

AIDS-Related Complex↗
PubMed1987

Comparison of indirect immunofluorescence and Western blot for detection of anti-human immunodeficiency virus antibodies.

There was 100% agreement between the results of indirect immunofluorescence (IF) and Western blot testing when these methods were used to detect antibodies to the human immunodeficiency virus in sera from 25 patients with acquired immune deficiency syndrome (AIDS), 20 patients with AIDS-related complex, 186 subjects at high risk for AIDS, and 40 healthy heterosexuals. However, there was only an 88.7% correlation between IF and Western blot results for 728 sera from blood and plasma donor centers that were selected on the basis of screening enzyme immunoassay reactivity. IF tests yielded nine false-negatives and were equivocal, yielding a nonspecific pattern of reactivity for both infected and uninfected cells for 73 of these specimens. The IF and Western blot methods were equal in performance for the detection of anti-human immunodeficiency virus antibodies in the high-risk and unselected low-risk groups, proving to be a practical approach for testing specimens from these subjects. However, the Western blot was the most acceptable method for the validation of specimens from groups at low risk for AIDS that were selected based on enzyme immunoassay reactivity.

AIDS-Related Complex↗
PubMed1987

Human immunodeficiency virus infection in heterosexual intravenous drug users in San Francisco.

To investigate the risk of infection with the human immunodeficiency virus (HIV) in San Francisco, the prevalence of antibodies to HIV was determined in 281 heterosexual intravenous drug users recruited from community-based settings. Ten per cent of subjects had ELISA and Western blot confirmed seropositivity for antibodies (95 per cent CI 6.8-14.2 per cent). Analysis of behavioral factors revealed an increased risk of seropositivity in addicts who reported regularly sharing needles when injecting, particularly those sharing with two or more persons (odds ratio = 5.43; 95 per cent CI 1.08-52.5). Blacks and Latinos also had a greater prevalence of seropositivity than Whites, and this finding persisted after adjustment for needle sharing (adjusted odds ratio = 2.8; 95 per cent CI .84-8.59). Seropositivity was not associated with age, sex, duration of drug use, or history of prostitution. These data indicate that a new epidemic of AIDS (acquired immunodeficiency syndrome) in intravenous drug users, similar to that which has occurred among homosexuals in San Francisco, is possible. The relatively low seroprevalence in 1985 provides health officials an important opportunity to intervene and attempt to prevent widespread infection of drug users with HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1987

T-lymphocyte subsets in nude mice with Giardia muris infection.

The aim of this study was to compare the relative percentages of T-lymphocyte subsets in athymic (nude) mice and immunocompetent BALB/c mice, with and without Giardia muris infection. Suspension of mononuclear leukocytes from blood, spleen, and Peyer's patches of uninfected mice were incubated with fluorescent monoclonal antibodies (MAbs) directed against mouse T-lymphocytes (anti-Thy-1.2 MAb), T helper/inducer lymphocytes (anti-L3T4 MAb), or T suppressor/cytotoxic lymphocytes (anti-Ly-2 MAb), and examined by fluorescence microscopy to quantify each of these cell populations. While the percentages of Thy-1.2+, L3T4+, and Ly-2+ lymphocytes are all reduced in nude mice, L3T4+ lymphocytes were found to be especially depleted, resulting in a reversed L3T4+/Ly-2+ ratio (less than 1) in all of the nude mouse tissues examined. BALB/c and nude mouse Peyer's patch T-cell subsets were quantified at various times during enteric Giardia muris infection. Unlike immunocompetent BALB/c mice, nude mice have an impaired ability to clear this infection. It was found that clearance of G. muris infection is associated with a Peyer's patch L3T4+/Ly-2+ ratio of greater than or equal to 2, and that this infection does not alter the percentages of Peyer's patch Thy-1.2+, L3T4+, or Ly-2+ lymphocytes in BALB/c mice or nude mice. The data obtained in the present work and in other studies suggest that the impaired capacity of nude mice to clear G. muris infection results from deficiency of L3T4+ lymphocytes.

Animals↗
PubMed1987

Absence of HIV antibody among dental professionals exposed to infected patients.

Dental professionals have relatively frequent skin contact with saliva and small amounts of blood of patients infected with the human immunodeficiency virus (HIV). Despite this exposure, none of 255 dentists, hygienists and chairside assistants had the antibody to HIV following an estimated 189 or more exposures. These data provide further evidence that casual contact with the saliva of HIV-infected persons, such as may occur in households, the workplace or in public places, is unlikely to result in transmission of HIV to uninfected persons. Because of the small sample size in this study, however, and the relatively high frequency of exposure of HIV-infected patients that we found, we recommend that dental care professionals increase their use of disposable gloves and adhere to the Centers for Disease Control's guidelines for infection control practices for dentistry until more is known about the transmission of this virus.

Acquired Immunodeficiency Syndrome↗