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Biomedical subjects

D L Archer

Publications and source records attributed to D L Archer.

33 records · Page 2Linked to original sources
PubMed1981

Reduction in antiviral activity of human beta interferon by gallic acid.

Gallic acid (GA) is a common part of the human diet, both in the free form and as a metabolite of tannic acid and propyl gallate. Cell cultures were incubated with mixtures of either GA and beta interferon (IFN-beta) (formerly fibroblast IFN) or medium and IFN-beta. The cells were subsequently challenged with virus. The virus plaque yields were greater in cells incubated with IFN-beta and GA than in cells incubated with IFN-beta and medium, indicating that in the former mixture, IFN-beta had lost antiviral activity. The magnitude of the loss was dependent upon the GA concentration. IFN-alpha and IFN-gamma (formerly leukocyte IFN and immune IFN, respectively) were not similarly affected. The effect of GA on IFN-beta could be reversed with 2-mercaptoethanol, suggesting a possible sulfhydryl involvement. Extensive dialysis of IFN-beta-GA mixtures to remove the GA failed to reverse the reduction in antiviral activity. This suggests that a direct and irreversible interaction between IFN-beta and GA took place, reducing the activity of IFN-beta. The significance of this finding with regard to virus infections of the intestine is discussed.

Binding Sites↗
PubMed1981

Specific receptor binding of staphylococcal enterotoxins by murine splenic lymphocytes.

We describe a reliable assay to measure the specific binding of 125I-labeled staphylococcal enterotoxin A (SEA) by murine spleen cells. Toxin binding by lymphocytes was specific in that it was inhibited by unlabeled SEA but not by unrelated proteins. The biological activity of SEA (T-lymphocyte mitogenesis) correlated with toxin binding to splenic lymphocytes. In the presence of high concentrations of [125I]SEA, specific binding increased rapidly and approached saturation after 2 h. Toxin binding was sensitive to temperature and pH and was directly proportional to the concentration of spleen cells in the incubation mixture. We estimated that there was a single class of toxin-binding sites, which had an apparent equilibrium dissociation constant (Kd) of 8 x 10(-7) M and numbered 3,600 sites per cell. SEA and the antigenically distinct compounds staphylococcal enterotoxins B and E in excess competitively inhibited binding of [125I]SEA to mouse spleen cells. Our data suggest a common class of binding sites for the three staphylococcal enterotoxins.

Animals↗
PubMed1980

Effects of toxicants on T-cell subpopulations as determined by lymphokine activity.

Selective depletion of T1 and T2 lymphocyte subpopulations of mouse spleens was accomplished by injecting mice subcutaneously with 5 mg cortisone acetate (CA) or 0.1 ml antithymocyte serum (ATS), respectively. Selectively depleted and control spleen cells were cultured in vitro and were tested for their ability to produce the lymphokine immune interferon (IIF) in response to the following mitogens: staphylococcal enterotoxin A (SEA), concanavalin A (ConA), and phytohaemagglutinin-P (PHA). The data indicate that SEA and PHA induce IIF from T1 and T2 cells respectively; ConA induces IIF from both T1 and T2 cells. Mice were also injected subcutaneously with 10 mg gallic acid (GA) and the pattern of mitogen-induction of IIF from GA-treated spleen cells was compared with that of CA- and ATS-treated spleen cells. GA pretreatment of mice, like CA pretreatment, resulted in a significant decrease in SEA-induced IIF; GA probably exerts its effect on T1 suppressor cells.

Animals↗
PubMed1974

Control of interferon, migration inhibition factor, and expression of virus capsid antigens in Burkitt's lymphoma-derived cell lines: role of L-arginine.

The effects of an arginine-utilizing mycoplasma, Mycoplasma arginini, and of varying levels of arginine in the growth media of the Epstein-Barr virus (EBV)-containing EB1 and EB3 cell lines, and the EBV-free RPMI 1788 cell line, were studied. l-Arginine, at a concentration of 0.1 mM in the growth medium, led to a reduction of the EBV capsid antigen content of the EB1 and EB3 cells lines as determined by indirect immunofluorescence, and M. arginini infection enhanced this reduction. The synthesis of two immune products, interferon and macrophage migration inhibition factor, was enhanced by growing the cell lines in medium containing arginine at a concentration of 0.1 mM, but the RPMI 1788 cell line produced much less of both products than EB1 or EB3 under these conditions. Infection of the cell lines with M. arginini reduced the amount of interferon produced and completely inhibited macrophage migration inhibition factor synthesis. The addition of arginine to a final concentration of 0.6 mM in the growth medium caused a dual effect: the EB1 and EB3 cell lines maintained the original level of EBV capsid antigens, even when infected with M. arginini; immune product synthesis was greatly reduced or completely inhibited by the addition of arginine, and M. arginini infection caused no further reduction of immune product synthesis.

Antigens, Viral↗
PubMedDate not supplied

US food legislation.

Explore the source record for details and available documents.

Food Contamination↗
PubMedDate not supplied

Food counseling for persons infected with HIV: strategy for defensive living.

More than a million people in the United States are now infected with human immunodeficiency virus (HIV), and by 1991, the United States will record 270,000 cases of acquired immunodeficiency syndrome (AIDS). At present, there is no way to estimate the number of AIDS patients who will be living in 1991. Intestinal diseases exert considerable morbidity and mortality on AIDS patients and persons with AIDS-related complex. The elevated frequency of certain intestinal infectious diseases in homosexual male AIDS patients has been attributed to sexual practices, but food seems a probable vector for some proportion of the infections in all AIDS-affected groups. Intestinal infectious diseases and resulting systemic infections can be life-threatening to AIDS patients. The infections may serve as cofactors that hasten HIV disease progression to AIDS, but absolute proof of this hypothesis is lacking. The longer the HIV-infected person maintains good general health and avoids potentially lethal infectious diseases, the better are the chances that effective treatments will be developed and made available. Foodborne diseases are generally avoidable, and increased education of AIDS patients and their physicians as to their nature is the key to their prevention.

AIDS-Related Complex↗
PubMedDate not supplied

Estimates of incidence and costs of intestinal infectious diseases in the United States.

The incidence of acute episodes of intestinal infectious diseases in the United States was estimated through analysis of community-based studies and national interview surveys. Their differing results were reconciled by adjusting the study population age distributions in the community-based studies, by excluding those cases that also showed respiratory symptoms, and by accounting for structural differences in the surveys. The reconciliation process provided an estimate of 99 million acute cases of either vomiting or diarrhea, or both, each year in this country, half of which involved more than a full day of restricted activity. The analysis was limited to cases of acute gastrointestinal diseases with vomiting or diarrhea but without respiratory symptoms. Physicians were consulted for 8.2 million illnesses; 250,000 of these required hospitalization. In 1985, hospitalizations incurred $560 million in medical costs and $200 million in lost productivity. Nonhospitalized cases (7.9 million) for which physicians were consulted incurred $690 million in medical costs and $2.06 billion in lost productivity. More than 90 million cases for which no physician was consulted cost an estimated $19.5 billion in lost productivity. The estimates excluded such costs as death, pain and suffering, lost leisure time, financial losses to food establishments, and legal expenses. According to these estimates, medical costs and lost productivity from acute intestinal infectious diseases amount to a minimum of about $23 billion a year in the United States.

Adolescent↗
PubMedDate not supplied

Listeria methods development research at the Eastern Regional Research Center, U.S. Department of Agriculture.

Listeria methods research at the U.S. Department of Agriculture, Eastern Regional Research Center, has concentrated on 2 areas during the past year. The first was development of techniques for assessing isolation methods for their ability to detect sublethally stressed cells. It appears that a number of widely used media do not accurately detect Listeria that have been injured by thermal processing or acidification. The second was development of improved plating media. One, modified Vogel-Johnson agar, shows promise; it is highly selective and quantitative, and eliminates the need to select colonies on the basis of a blue color when illuminated with reflected light.

Animals↗