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Biomedical subjects

C Moroni

Publications and source records attributed to C Moroni.

At least 109 records · Page 6Linked to original sources
PubMed1980

Antibody directed against Friend leukemia virus stimulates DNA synthesis in a subpopulation of mouse B lymphocytes.

Goat and rat antisera directed against Friend leukemia virus (anti-FLV) were found to be B-lymphocyte mitogens stimulating DNA synthesis in these cells but not in T lymphocytes. Membrane fluorescence microscopy showed that anti-FLV reacts with a subset of B lymphocytes of which the majority express immunoglobulin mu chains. The mitogenic effect was found with all mouse strains tested including 129 and AKR. Absorption experiments with purified viruses indicated that the mitogenic effect is specific for an antigen present in murine leukemia viruses of the FMR subgroup. In absorption experiments with viable cells, the antigen involved in mitogenicity was found to be expressed on Friend erythroleukemia cell lines (4/4) and on myelomas (2/2) but not on normal thymus T lymphomas (0/2) or on rabbit or mink cells infected with BALB/c xenotropic virus. Preincubation of spleen cells with anti-gp70 antiserum inhibited the mitogenic effect of anti-FLV but not of lipopolysaccharide.

Animals↗
PubMed1980

Foetal calf serum acts as an inducer of endogenous C-type virus in mouse lymphoid cells.

Several B-lymphocyte mitogens have been previously characterized as efficient inducers of endogenous C-type viruses in mouse spleen cell cultures. We now report that foetal calf serum is also capable of inducing C-type virus release in such cultures. While virus induction by B-cell mitogens was found to be serum independent, the combined effects of serum and mitogens were found to be additive and, with some serum batches, synergistic. The kinetics of induction of virus release by serum was very similar to the established pattern using mitogens. The effect of serum was concentration-dependent. The serum lipoprotein fraction prepared by density ultracentrifugation contained virus-inducing activity. By co-cultivation with mink CCL64 cells, stable lines of mouse xenotropic C-type virus could be recovered from cultures which contained serum, serum lipoprotein fraction or mitogens, but not from control cultures. Preliminary evidence indicates that human sera contained a similar virus-inducing activity in the lipoprotein fraction.

Animals↗
PubMed1978

Mitogen induction of murine C-type viruses. IV. Effects of lipoprotein E. coli, pokeweed mitogen and dextran sulphate.

Lipoprotein E. coli, a B-cell mitogen, is identified as a new agent inducing the release of endogenous C-type virus from mouse spleen cells. Like lipopolysaccharide, a previously identified inducer, this compound has a synergistic effect with 5-bromo-2'-deoxyuridine. Induced virus has the characteristic density as well as morphology of C-type viruses. Budding viruses are detected on cultured BALB/c cells by electron microscopy 2 to 4 days following culturing in the presence of lipoprotein. Pokeweed mitogen, a compound mitogenic for T- and B-cells was negative when tested for virus induction, both alone and in combination with 5-bromo-2'-deoxyuridine. Dextran sulphate, another B-cell mitogen, was negative for induction as well. However, when, combined with lipopolysaccharide, it enhanced the virus release induced by this mitogen. In contrast, no additive effects were observed either by combining dextran sulphate with other virus amplifying mitogens or by combinations of mitogens which both have virus-inducing ability. This finding is discussed with respect to B-cell differentiation.

Animals↗
PubMed1978

Immunosuppressive activity of antibody directed against endogenous C-type virus interferes with early events of the immune response.

We have analyzed the effects of an antiserum prepared against BALB/c endogenous xenotropic C-type virus on the humoral immune response of mice. Both in vivo and in vitro, this serum suppresses the response to sheep red blood cells, an effect that can be absorbed out by purified BALB/c xenotropic C-type virus or Friend leukemia virus, but not by Rous sarcoma virus. The serum produces its maximum effect when administered together with or before the antigen, but not 24 hr later. This suggests that it acts on an early event of the immune response. Evidence is presented to show that the critical viral antigen is expressed before the spleen cells are experimentally stimulated by antigen. The same immunosuppressive effect was observed in a variety of mouse strains, including the high-leukemia incidence AKR strain and virus-free 129/J mice, indicating that it is independent of the expression of endogenous virus. The finding that a viral antigen is involved in the transition from a resting to a dividing lymphocyte is discussed with respect to viral involvement in leukemia.

Animals↗
PubMed1977

Metoclopramide increases plasma aldosterone concentration in man.

Plasma Aldosterone (PA) response to metoclopramide (10 mg i.v.) was studied in 11 normal, 2 hypophysectomized subjects and in one patient with bilateral adrenal hyperplasia. All the subjects were kept on a normal sodium and potassium intake. Four normal subjects were pretreated with 1 mg of dexamethasone in order to inhibit endogenous ACTH. In all subjects metoclopramide elicited a prompt rise of PA comparable to that obtained with angiotensions or ACTH. No significant change of blood pressure, serum electrolytes, plasma renin activity, Plasma Cortisol (PC) was detected. The lack of PC response to metoclopramide and the PA increase in dexamethasone pretreated subjects rule out an ACTH mediated effect. The increase of PA in hypophysectomized subjects, in whom metoclopramide did not stimulate any prolactin release, rules out a prolactin mediated effect. Metoclopramide increases plasma aldosterone concentration probably via a direct action on the adrenal glomerular zone or throught another unknown mechanism.

Adrenal Glands↗
PubMed1976

Mitogen induction of murine C-type viruses. I. Analysis of lymphoid cell subpopulations.

We reported previously in vitro induction of endogenous C-type viruses from normal mouse spleen cells by lipopolysaccharide (LPS) as well as by combination treatment with concanabalin A and 5-bromo-2'-deoxyuridine (Con A/BrdU). To identify the cell types sensitive to virus induction and to study the relationship of mitogenicity to virus induction we have compared T cell populations (BALB/c thymus cells and cortisone-resistant thymus cells), B cell populations (nu/nu spleen cells and lymph node cells), adherent BALB/c peritoneal cells and mixed populations (BALB/c spleen cells, macrophage-depleted BALB/c spleen cells, and lymph node cells). LPS-induction occurred only in B cell-containing populations. In contrast, induction by Con A/BrdU depended on the presence of both T and B cells. In both instances, neither macrophages nor hemopoietic cells appeared to be a major source of virus. Treatment with anti-Ig serum and complement reduced virus induction by LPS/BrdU but not by Con A/BrdU suggesting that different cell populations produce virus after stimulation with these two different mitogens.

Animals↗