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F Dupuis

Publications and source records attributed to F Dupuis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Human bone marrow fibroblasts--an overview of their characterization, proliferation and inflammatory mediator production.

Bone marrow fibroblasts regulate hematopoiesis by interacting directly (cell-to-cell contact) with hematopoietic cells and by secreting regulatory molecules (such as GM-CSF, M-CSF, IL6 and LIF) that modulate hematopoiesis either in a positive or a negative manner. Several cytokines (such as bFGF, EGF, PDGF and TGF-beta) affect the growth of human marrow fibroblasts in vitro. Further in vivo studies are still required to clarify the role of marrow fibroblasts and their interactions with hematopoietic progenitors during myelofibrosis and leukemic diseases.

Bone Marrow↗
PubMed1996

PAF and haematopoiesis: IX. Platelet-activating factor increases DNA synthesis in human bone marrow cells.

Platelet-activating factor (PAF) is present in human bone marrow leading us to investigate its effect on human bone marrow cell proliferation. While PAF (0.1 microM to 1 nM) stimulates the incorporation of [3H]thymidine by freshly isolated adherent human bone marrow cells, PAF has no effect on non adherent cells. A non-metabolizable PAF agonist is more potent than PAF to stimulate thymidine incorporation in adherent cells. The precise role of PAF in human haematopoiesis in vivo remains to be clarified.

Bone Marrow↗
PubMed1996

PAF and hematopoiesis. VIII. Biosynthesis and metabolism of PAF by human bone marrow stromal cells.

Human bone marrow stromal cells were studied for their ability to synthesize and to metabolize platelet-activating factor (PAF), a lipidic compound with potent immunoregulatory properties. When stimulated with 2 microM calcium ionophore for 60 minutes, cultures of stromal cells increased their PAF production (3.52 +/- 0.91 ng/1 x 10(6) cells) compared with controls (0.82 +/- 0.13 ng/1 x 10(6) cells). Addition of exogenous lyso PAF (100 nM) and acetyl-CoA (100 microM) during calcium ionophore stimulation did not change the PAF production. The synthesis of PAF was not influenced by the concentration of albumin in the incubation buffer. The PAF from stromal cells exhibited a hexadecyl chain at the sn-1 position of the molecule, as determined by reverse-phase HPLC. While stromal cells contained low amounts of PAF acetylhydrolase activity and did not secrete it in the culture medium, they metabolized exogenous PAF with 1-alkyl-2-acyl-glycero-phosphocholine and neutral lipids as the major metabolic products. The present results are the first to demonstrate the synthesis and metabolism of PAF by human bone marrow stromal cells. These data suggest that they might be a source of the PAF found in the human bone marrow and/or might be important in the regulation of its levels. The role of PAF on the proliferation and functions of human hematopoietic cells deserves investigation.

Bone Marrow↗
PubMed1995

PAF and haematopoiesis: III. Presence and metabolism of platelet-activating factor in human bone marrow.

Platelet-activating factor (PAF) is a phospholipid compound with major immunoregulatory activities. The present study shows that human bone marrow contains 576 +/- 39 pg PAF/ml (n = 35). Bone marrow-derived PAF exhibits the same biophysical and biological properties that synthetic PAF. PAF concentrations in bone marrow are correlated with the granulocyte (r = 0.4, P = 0.02) but not with the lymphocyte (r = 0.24, P = 0.17) and the monocyte (r = 0.12, P = 0.48) counts. In bone marrow PAF is inactivated by a plasma PAF acetylhydrolase activity (48.0 +/- 2.3 nmol/min per ml, n = 34). Experiments with [3H]PAF indicate that human bone marrow cells actively metabolize this potent molecule by the deacetylation-transacylation pathway. Results of this investigation indicate the permanent presence of significant amounts of PAF in bone marrow suggesting its putative involvement in the processes of bone marrow cell proliferation and maturation.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1995

PAF and haematopoiesis. IV. Modifications of spleen and thymus PAF contents after a single dose of the chemotherapeutic drug 5-fluorouracil in mice.

The spleen and thymus of mice were examined for the presence of PAF after injection of 5-fluorouracil (5-FU) (200 mg/kg). A significant increase of the spleen (P = 0.005) and thymus (P < 0.05) PAF concentrations was noted 48 h after 5-FU infusion. PAF levels in thymus are similar to those of controls from days 4 to 14. By contrast, spleen PAF significantly decreased (0.005 < P < 0.03) from days 7 to 14. Conversely, the 5-FU administration did not modify the spleen and plasma acetylhydrolase activity, suggesting that the variations of PAF levels in thymus and spleen were mainly due to differences of local PAF production. Thus, the chemotherapeutic drug 5-FU modulates in vivo PAF production in haematopoietic organs of mice. Considering the effects of PAF in the processes of B- and T-cell proliferation and functions, these results could be of importance for the role of PAF during human cancer therapy and haematopoiesis in vivo.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1994

PAF and hematopoiesis. II. Elevated levels of plasma paf acetylhydrolase after rapid infusion of 5-fluorouracil in cancer patients.

Blood platelet-activating factor (PAF) levels are regulated by a plasma PAF acetylhydrolase. We investigated its levels in cancer patients during the course of a 5-day 5-fluorouracil (5-FU) treatment. PAF acetylhydrolase increased in nine patients with daily bolus infusion of 0.4 g 5-FU per m2 of body surface (81.7 +/- 8.7 nmol PAF/min/ml vs. 66.6 +/- 7.0; P < 0.001 for day 5 as compared to day 1). By contrast PAF acetylhydrolase did not change in seven patients with continuous infusion of 5-FU. The meaning of these results is discussed in respect of the immunoregulatory role of PAF.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1993

Hormonal status and clinical relevance of hirsutism in elderly women.

Hirsutism is a common condition of elderly women, but its aethiopathogeny and its clinical implications remain unclear. We therefore studied circulating androgen concentrations in elderly women. In addition, this study aims to define a possible relationship between hirsutism and anthropometric determinations, bone mass and serum lipids. Androgen levels were determined at basal state, after adrenocorticotrophin (ACTH) stimulation and after dexamethasone administration in 10 hirsute elderly women and compared to 10 age-matched non-hirsute women. Anthropometric determinations included measurements of skinfold thickness and body mass index. Spinal bone mass density was assessed using dual photon absorptiometry. Hirsute women presented significantly higher levels of testosterone than controls (1.49 +/- 0.38 vs 0.59 +/- 0.05 nmol/l, mean +/- SEM; p < 0.05) and dihydrotestosterone (0.54 +/- 0.07 vs 0.32 +/- 0.03; p < 0.02). 17-hydroxyprogesterone levels after ACTH stimulation tended to be higher in hirsute women than in controls. No differences were observed between the two groups in serum oestrogen concentrations, plasma lipid pattern or bone mineral density. Hirsute women had a lower body mass index and lower calculated percentage body fat than the control group. We conclude that: (i) hirsutism of elderly women is associated with increased androgen levels, probably from adrenal origin; (ii) in some cases, enhanced response in 17-hydroxyprogesterone after ACTH stimulation suggests a partial adrenal 21-hydroxylase deficiency; (iii) hirsute women present anthropometric characteristics compatible with the known anabolic effect of androgens on fat-free mass.

Adrenocorticotropic Hormone↗
PubMed1983

[Surgical treatment of pilonidal disease. A new simplified technic].

A simplified technique for treatment of pilonidal sinus has been employed in 25 patients during the last 3 years. Initial results have been very encouraging as there have been no recurrences up to the present time. Mean duration of hospitalization was 3 days, patients can get out of bed after 24 hours, and work can be resumed after 2 weeks, complete healing requiring one month.

Acute Disease↗
PubMed1979

[Hemodialysis].

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Arteriovenous Shunt, Surgical↗