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Biomedical subjects

G Armstrong

Publications and source records attributed to G Armstrong.

At least 73 records · Page 4Linked to original sources
PubMed1984

Interaction of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) with owl monkey kidney cells in enhancing the yields of Herpesvirus saimiri (HVS) and its antigens.

Pre- and posttreatment with N-methyl-N'-nitro-nitrosoguanidine (MNNG) of owl monkey kidney (OMK) cells infected with Herpesvirus saimiri (HVS) resulted in one to three logs higher yields of virus, depending upon the dose of MNNG. A higher percentage of cells also showed HVS early antigen (EA) and late antigen (LA) by immunofluorescence when OMK cells infected with HVS were fed with medium containing MNNG. The high yields of HVS were also observed by electron microscopy. MNNG did not induce HVS-EA in HVS nonproducer lymphoblastoid T cells, nor did it enhance TPA-induced EA to LA. The data suggest that MNNG could be useful in obtaining high yields of virus and/or antigen-producing cells for immunofluorescence or other biochemical experiments, especially from those strains of HVS which grow poorly in vitro. The interaction of MNNG and HVS could also be useful for in vitro transformation or in vivo enhancement of the malignant process.

Animals↗
PubMed1983

Synthesis of kappa light chains by cell lines containing an 8;22 chromosomal translocation derived from a male homosexual with Burkitt's lymphoma.

Three cell lines were derived from a homosexual patient with probable acquired immunodeficiency syndrome and Burkitt's lymphoma. The cell lines produce an unusual strain of Epstein-Barr virus which will both transform cord blood lymphocytes and induce early antigens in Raji cells. Translocations between chromosomes 8 and 22 have occurred in all three lines, but the cells synthesize immunoglobulin M with light chains of the kappa type, in contrast to the usual concordance between a translocation involving chromosome 22 and lambda chain synthesis. Both kappa genes and one lambda gene are rearranged. These findings indicate either that translocation may occur as a separate event from immunoglobulin gene rearrangement or that the proposed hierarchical sequence of immunoglobulin gene rearrangements is not always adhered to. The data also imply that in cells containing a translocation between the long arm of chromosome 8 and a chromosome bearing an immunoglobulin gene, alteration of cellular myc expression may occur regardless of the immunoglobulin gene that is expressed.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Variations in the immune response to Herpesvirus saimiri in squirrel and rhesus monkeys.

Humoral and cell-mediated immunity (CMI) to herpesvirus saimiri (HVS), an oncogenic lymphotropic herpesvirus, was studied in squirrel and rhesus monkeys. Natural antibody to HVS was found in five of six squirrel monkeys but there was no evidence of specific CMI directed against HVS. Rhesus monkeys did not show natural antibody or CMI against HVS antigens. Immunization with HVS, however, produced both antibody and specific CMI in the rhesus monkeys, but no CMI developed in the squirrel monkeys. These findings are important in the development of animal models for the treatment of tumors associated with lymphotropic herpesviruses.

Animals↗
PubMed1982

Persistence of transforming and nontransforming Epstein-Barr virus in high passages of P3HR-1 cell lines.

At least three laboratories have reported that the P3HR-1 line, which had originally produced transforming Epstein-Barr virus (EBV), now produces only the nontransforming variant. Studies to determine whether these findings were universal or a consequence of specific cell lines or culture conditions were undertaken in P3HR-1 cultures of identical HLA types from five sources. All of the EBV preparations derived from cell lines cultured at 32, 34, and 35 degrees C transformed cord blood lymphocytes, whereas virus propagated at 37 degrees C did not usually transform. Furthermore, indirect immunofluorescence revealed that a monoclonal antibody directed against transforming EBV membrane glycoprotein bound to 10-12% of the P3HR-1 cells that had been continuously propagated at 34 degrees C, but the antibody did not bind to the same cells cultured at 37 degrees C. Although virus expression was completely repressed in transformed cord blood cells, transforming virus could be rescued by superinfection with nontransforming P3HR-1 EBV. Cells transformed with P3HR-1 virus induced poorly differentiated lymphomas in athymic nude mice after seven or eight passages. Whether all P3HR-1 cells have the potential to produce detectable quantities of transforming virus remains to be determined.

Animals↗
PubMed1982

Elevation of serum chemotactic factor inactivator activity in rabbits induced by inflammation and chemotactic factor.

Inflammatory mediators such as the vasoactive and chemotactic factors, which are formed during the activation of serum complement, are extremely potent biologic peptides and are thought to be under the rigid control of specific serum-derived regulators or inactivators, including the anaphylatoxin inactivator (AI) and the chemotactic factor inactivator (CFI). Our understanding of the biologic importance and implication of these regulators in inflammatory reactions is primarily based on in vitro observations, and there is only limited data on their in vivo importance. Previously, alterations in CFI and AI levels were detected in chronic inflammatory disease states, but no data on their activity or role during acute inflammatory reactions have been demonstrated. Here we demonstrate the elevation of serum CFI activity during acute inflammatory reactions in rabbits. Specifically, inflammatory reactions were induced in rabbits by intraperitoneal injections of 0.1% oyster glycogen. Rabbit serum CFI levels rose rapidly over the first 4 hours after glycogen injection, reaching levels 4-8 times higher than the preglycogen serum CFI levels. Additional studies demonstrated that acute elevations of serum CFI levels could also be induced in rabbits by intravenous infusion of activated rabbit serum or C5-derived chemotactic factors. Infusion of saline, albumin, or the synthetic chemotactic peptide f-Met-Leu-Phe did not cause elevation of the serum CFI levels in rabbits. Thus, we take these data to support our hypothesis that 1) CFI is a "hyperacute phase reactant" that is elevated during inflammatory reactions, and 2) that this elevation of serum CFI activity is probably triggered by the appearance of specific C5-derived chemotactic factors within the vasculature. These studies not only provide exciting new insights into the regulatory mechanisms involved in acute inflammatory reactions but suggest that novel approaches to antiinflammatory therapy may be forthcoming.

Acute Disease↗
PubMed1980

Herpesvirus saimiri-induced malignant lymphoma in inbred strain III/J rabbits (Oryctolagus cuniculus).

Four young strain III/J rabbits of both sexes were inoculated with a single dose of prototype partially purified Herpesvirus saimiri (HVS) via IV and IM routes. All inoculated animals had enlarged lymph nodes, and significant levels of antibodies to HVS early, late, and membrane antigens were detectable during the infection. The animals died or were killed and HVS was isolated from the peripheral blood mononuclear cells and the various lymph nodes but not from the kidney. Microscopic examination showed that these animals had poorly differentiated lymphomas. The response of mononuclear cells to PHA from peripheral blood of infected animals showed depressed cell mediated immune responses. Humoral and cellular immunity responses during tumorigenesis were comparable to those reported in nonhuman primates with HVS-induced tumors. Thus, the inbred strain III/J appears to be an inexpensive suitable model for studies of oncogenic herpesvirus-induced cancers.

Animals↗
PubMed1978

National Clearinghouse for Poison Control Centers.

The Clearinghouse was originally conceived to coordinate information flow among the then few Poison Control Centers. Services were to be provided through the state health departments where complete control over the individual state's poison centers was to reside. No authority to establish or regulate centers, or to set standards for staffing and operation of centers, or to designate regional centers was granted. However, growth in the numbers of centers, more sophistocation in the state of the art, more demands for product and human experience data, calls for research support, regionalization, standards setting, competency testing, and others has led to an increasing call for more and more Clearinghouse involvement in the entire poison control program. Though staffing and funding remains fairly constant, the Clearinghouse hopes to be as involved and to provide as great a service as possible to those involved in clinical toxicology and poison control.

Computers↗
PubMed1978

Experimental infection of Callithrix Jacchus marmosets with Herpesvirus ateles, Herpesvirus saimiri, and Epstein Barr virus.

We inoculated common marmosets (Callithrix Jacchus) with Herpesvirus ateles (HVA), Herpesvirus saimiri (HVS), and Epstein-Barr virus (EBV). HVA-induced tumors contained several cell types, including giant cells reminiscent of the Sternberg-Reed cells observed in human Hodgkin's disease. HVS and EBV did not induce tumors, although HVS was present in lymphocytes and elicited a strong antibody response. EBV elicited only a variable antibody response. We feel that more common marmosets should be used to determine if the pathologic and immunologic lesions caused by HVA would be a suitable animal model for Hodgkin's disease and/or other malignant lymphomas of man. Inconsistency in the induction of tumors by EBV and HVS in common marmosets suggets that this species may be a different type of model for human cancer research than the cottontop marmoset, which is the most susceptible animal host for EBV and HVS oncogenesis.

Animals↗