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Biomedical subjects

M Pelletier

Publications and source records attributed to M Pelletier.

At least 109 records · Page 6Linked to original sources
PubMed1979

[Stimulation of proliferation of rat spleen cells, in vitro, by a nonspecific acute inflammatory exudate. Modulation of cell response to phytohemagglutinin (PHA)].

The effect of an acute non-specific inflammatory exudate with mitogenic activity on macrophages in culture has been tested on the spontaneous and PHA-induced DNA synthesis of spleen cells in vitro. Stimulatory effect of this exudate was observed on spontaneous DNA synthesis which was detectable over a range of 1 : 4 to 1 : 4,000 concentrations. After optimal PHA stimulation, an inhibition of mitogen-induced DNA synthesis was observed when the cells were exposed to the highest concentrations (up to 1 : 128) of the exudate. Thereafter, the phenomenon could be reversed and the stimulation was maximal at a concentration of 1 : 2,000. When a sub-optimal dose of PHA was used, the simulatory effect was more pronounced and detected from 1 : 8 up to 1 : 4,000 concentrations.

Acute Disease↗
PubMed1979

In vitro effect of an acute nonspecific inflammatory exudate on tritiated-thymidine incorporation by unstimulated and PHA-stimulated spleen cells.

The effect of an acute nonspecific inflammatory exudate with mitogenic activity for macrophages in culture has been tested on the spontaneous and PHA-induced DNA synthesis by spleen cells in vitro. Stimulatory effect of this exudate was observed on the spontaneous DNA synthesis which was detectable over a range of 1:4 to 1:4096 concentrations. After optimal PHA stimulation, an inhibition of mitogen-induced DNA synthesis was observed when the cells were exposed to the highest concentrations (up to 1:128) of the exudate. Thereafter, the phenomenon could be reversed and the stimulation was maximal at the concentration of 1:2048. When a suboptimal dose of PHA was used, the stimulatory effect was more pronounced and detected from 1:8 up to 1:4096 concentrations.

Animals↗
PubMed1979

Possible C1q bypass loop activation in the haemolytic uraemic syndrome.

Ultrastructural and immunofluorescent microscopic studies were performed on renal tissue obtained from nine patients during the acute and convalescent phase of the haemolytic uraemic syndrome (HUS). All had glomerular deposits of IgM in the absence of circulating immune complexes. This was associated with deposition of C1q during the acute phase, and properdin and C3 during the convalescent phase. C4 was consistently absent. Since such a pattern of complement deposition does not fulfil criteria either for alternate or classical pathway activation, the possibility of C1q bypass loop activation by IgM is suggested.

Child↗
PubMed1978

[Origin of a mitogrenic factor for cultivated macrophages (IMF: Inflammatory Mitogenic Factor) found in exudates of non-specific acute inflammation].

The mitogenic activity of inflammatory exudate obtained from irradiated Rats is reduced. After transfer of bone marrow syngeneic cells into irradiated Rats this mitogenic activity is further decreased, while after transfer of thymic cells it is increased. It is postulated that the mitogenic activity of inflammatory exudate could be related to thymic cells and that T lymphocytes may be involved in non specific-inflammatory reactions.

Acute Disease↗
PubMed1978

Induction of macrophage DNA synthesis in vitro by non-immunological inflammatory exudates: effect of irradiation and thymus or bone marrow cell reconstitution.

An acute inflammatory exudate possesses mitogenic activity in that it is able to induce both DNA synthesis and proliferation of macrophages in vitro. This activity is reduced however if the inflammatory exudate is obtained from irradiated rats (900 r). Transfer of bone marrow syngeneic cells into irradiated rats does not reverse this reduction. On the contrary the decrease of mitogenic activity is more pronounced. On the other hand transfer of thymic syngeneic cells not only restores the mitogenic activity of inflammatory exudate from irradiated rats but increases it. Transfer of both types of cell together fully restores the mitogenic activity of inflammatory exudate. It is postulated that the mitogenic activity of inflammatory exudate could be related to thymic cells and that T lymphocytes may be involved in non-specific inflammatory reactions.

Animals↗
PubMed1976

Induction of DNA synthesis in rat peritoneal macrophages in culture by a pleural inflammatory exudate.

Peritoneal macrophages in culture are blocked in the G0 phase of the cell cycle, but retain many of their functional characteristics such as phagocytic ability. Peritoneal macrophages have been thought to be a terminal cell type. It has been investigated whether such properties could be modified by a substance released in acute inflammatory exudates. For this purpose a pleural exudate obtained from rats injected with dextran (40,000) 4 hours before, was centrifuged to eliminate cells, sterilized by filtration on Millipore filter 0.22 mum and diluted 50% with 199 medium culture. This medium was used to treat normal and activated peritoneal macrophages in culture. The effects were observed 24, 48, 72, 96 hours after the beginning of treatment. An enhancement of spreading and capacity of phagocytosis was observed 24 hours after the beginning of treatment. After 48 hours, the number of cells incorporating tritiated thymidine increased and became highest 4 days later. These phenomena were also obtained with pleural exudate of inbred rats (Lewis, Wag) treating macrophages of the same strain and with rat pleural exudate treating mouse macrophages. No effects were observed with dextran alone. The chemical nature of the stimulatory factor remains to be elucidated.

Animals↗
PubMed1976

Thymic hormone activity and spontaneous autoimmunity in dwarf mice and their littermates.

Serum thymic hormone activity (TA) was determined in hereditary hypopituitary dwarf mice (dw/dw) and their littermates (+/dw or +/+). It was found to be very low in the dwarf animals in comparison to their littermates. At 14 weeks of age, the dwarf littermates exhibited significant glomerular lesions characterized by deposits of IgG, IgG1, IgG2, IgA, IgM and C3, which were augmented by thymectomy of adult females. In contrast, hypopituitary dwarf mice had minimal glomerular deposits of immunoglobulins. Unlike these animals, their littermates showed antinuclear antibodies (ANA) and anti-deoxyribonucleic acid (DNA) antibodies in their serum. The present findings are discussed in relation to recent hypotheses on: (1) the role of the hypophysis in thymus-dependent immunological functions; and (2) the significance of T-cell deficiency in the development of autoimmunity.

Animals↗