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Biomedical subjects

M Jourdan

Publications and source records attributed to M Jourdan.

At least 73 records · Page 4Linked to original sources
PubMed1987

Production of growth factors by human myeloma cells.

Using in vitro-growing myeloma cell lines, we studied the growth factors involved in human multiple myeloma, and particularly the potential of autocrine secretion and response to B-cell growth factor (BCGF) of RPMI 8226, the best-documented Epstein-Barr virus-negative human myeloma cell line. We found that three myeloma cell lines (RPMI 8226, U266, and IM9) produce an autostimulatory growth factor (AGF) and thus increase their own proliferation by 2- to 3-fold in cells cultured at low density. Optimal AGF production was obtained after 24 h of culture at a cell density ranging from 2.5 to 5 million cells/ml. The three myeloma cell lines produce type II BCGF, able to induce the proliferation of highly purified human peripheral blood B-cells, only after anti-mu activation. The BCGF produced by RPMI 8226 can be absorbed onto RPMI 8226 cells together with the RPMI 8226 AGF, and the two are copurified on gel filtration in a peak with an apparent molecular weight of 70,000. RPMI 8226 can be efficiently activated by human high molecular weight BCGF II (Mr 50,000) and less extensively by BCGF I (Mr 12,000). RPMI 8226 does not produce either detectable IL1 or interferons gamma and alpha and IL1 and gamma-IFN had no stimulating effect on RPMI 8226 proliferation. Our findings support the conclusion that RPMI 8226 produces a BCGF II working as an AGF.

Burkitt Lymphoma↗
PubMed1986

Behavioral fever and therapy in a rickettsia-infected Orthoptera.

Gryllus bimaculatus were infected with an intracellular prokaryote, Rickettsiella grylli, then reared either at fixed temperatures or in a temperature gradient (22-36 degrees C) where they could select the temperature they preferred. Only 50% of the infected insects reared at 28 degrees C or less survived after 20 days, against 75% of those reared at 30 degrees C or more and 90% of those in the temperature gradient. Examination of smears of insect tissue showed that all (100%) of the infected insects reared between 23 and 29 degrees C had developed a strong rickettsial infection. Only 20% of the insects reared in a gradient of temperature showed signs of strong infection. Body temperature of crickets in the temperature gradient, recorded using thin thermocouples, was 33 degrees C in infected crickets and 26.6 degrees C in controls. It is concluded that thermoregulatory behavior was used by the insects to produce a fever when infected with Rickettsiella grylli. This protected them and increased survival capacity.

Animal Husbandry↗
PubMed1986

Production of interleukin 2 in multiple myeloma.

The production of interleukin 2 (IL-2) by peripheral blood mononuclear cells (PBMC) was studied in 15 normal controls (NC) and 29 patients with multiple myeloma (MM), including 19 patients with active disease (i.e. diagnosis, relapse) and 10 with inactive disease (i.e. complete remission and off-treatment plateau). IL-2 was produced after stimulation of PBMC with PHA alone or with PHA and PMA. The role of suppressor factors/cells on IL-2 production was evaluated using indomethacin and irradiation of PBMC. T cells and T cell subsets (i.e. helper/suppressor T cells) were defined using standard monoclonal antibodies (T3, T4, T8). The production of IL-2 in active MM was similar to that of NC, using either PHA or PHA and PMA. However, a constant defect of prostaglandin-mediated suppressor cells was observed in patients in plateau, with a significant increase of IL-2 production in comparison to that of NC or active MM. IL-2 is an essential factor involved in T cell proliferation. Recent data demonstrate that it plays a role in B cell proliferation and differentiation into antibody-secreting cells. Suppression of antibody synthesis is a major feature of active (but not inactive) MM. The fact that IL-2 production was not affected in MM, in spite of an imbalance of some T cell subsets, is of major interest.

Humans↗
PubMed1985

Control of human T-colony formation by interleukin-2.

T-colony formation can be induced in PHA-stimulated peripheral blood mononuclear cells (PBM) from man, but not in PHA-stimulated purified T cells, the latter requiring the presence of factors produced by PHA-stimulated PBM and termed T-colony promoting activity (TCPA). In this paper, we demonstrate that interleukin-2 (IL-2), the growth hormone of T lymphocytes, controls T-colony formation. We show that: IL-2 activity and TCPA produced by PHA-activated PBM are co-purified by gel filtration and chromatography on blue agarose, a procedure which yields a 850-fold IL-2 purification; recombinant IL-2, produced by genetically manipulated Escherichia coli, can induce T-colony formation in PHA-stimulated purified T cells; Monoclonal antibody against the IL-2 receptor (anti-Tac antibody) completely inhibits the T-colony formation in PHA-stimulated PBM when directly added to the culture system.

Antibodies, Monoclonal↗
PubMed1985

Interleukin 2 production in B cell chronic lymphocytic leukemia.

Interleukin 2 (IL 2) production by phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) was investigated in 22 patients with active untreated B cell chronic lymphocytic leukemia (B-CLL) and in 15 healthy donors. PBMCs from healthy donors demonstrated an IL 2 synthesis of 12.4 +/- 10 U/mL. B-CLL PBMCs produced a significant amount of IL 2 (8 +/- 6.6 U/mL) despite the low percentage of T cells (13% +/- 8%) associated with this disease compared with that found in healthy donors (63% +/- 7.5%). If IL 2 production is expressed as units per milliliter per 10(4) T cells, its level in patients with B-CLL (1.1 U/mL/10(4) T cells) is five times greater than that of the controls (0.19 units). When expressed as units per milliliter per liter of blood, the B-CLL patients produce approximately 12 times as much IL 2 as controls. IL 2 production in normal controls was doubled after irradiation of PBMCs or addition of indomethacin. This increase was not seen with B-CLL PBMCs suggesting that the latter have been devoid of prostaglandin-producing normal IL 2 suppressor cells. By mixing normal or B-CLL T cells with non-T cells we found that T cells from patients with B-CLL stimulated by normal accessory cells produced the same amount of IL 2 as normal T cells. Moreover, B-CLL non-T cells (mainly B leukemic cells) produced no IL 2 themselves but played a much more efficient role in IL 2 production than did non-T cells from healthy donors. This was not due to detectable IL 1 production by these cells. The IL 2 produced by B-CLL PBMCs was partially purified and recovered in a 16,000 mol wt fraction, the same mol wt as IL 2 from normal cells.

Aged↗
PubMed1984

The role of interleukin-2 in T colony formation by human pre-T cells (pTCFC).

Human T lymphocyte colonies may be grown in agar from pre-T peripheral blood cells. Pre-T cells giving rise to these colonies represent 0.5% of the non-adherent, E rosette and Leu 1 depleted mononuclear cell subpopulation. T colony formation is induced by PHA stimulation and only if media conditioned by PHA stimulated peripheral blood lymphocytes (PHA-LCM) is added. These media contained interleukin-2 (IL-2) and T colony promoting activity (TCPA) for pre-T cells. TCPA is co-eluted with IL-2 by gel filtration with an apparent molecular weight of 18,000 daltons. Moreover, when PHA-LCM are absorbed on IL-2-dependent cultured T cells, TCPA is removed as well as IL-2. In attempt to further demonstrate the role of IL-2 in T colony formation by the pre-T cells we used the anti-Tac monoclonal antibody directed against IL-2 receptor. We demonstrated that anti-Tac inhibits T colony formation in a dose-dependent manner in pre-T cells. We conclude that IL-2 is the essential exogenous factor contained in PHA-LCM which allows pre-T cell differentiation expression and proliferation in agar medium.

Antigens, Surface↗
PubMed1983

The role of interleukin 1 and interleukin 2 in human T colony formation.

We investigated the roles of interleukin 1 (IL1) and interleukin 2 (IL2) on T colony formation by PHA-stimulated peripheral blood lymphocytes (PBL). Purified T cells stimulated by PHA could not generate T colonies as did PBL. Media conditioned by PHA-stimulated PBL (PHA-LCM) contained IL2 and a T colony-promoting activity (TCPA) which induced T colony formation in PHA-stimulated purified T cells. IL2 and TCPA are coeluted in the same peak of 18,000 molecular weight after gel filtration chromatography. Moreover, TCPA present in the PHA-LCM could be absorbed on IL2-sensitive cells which possessed specific receptors for IL2. These results suggest that TCPA and IL2 are related entities. Monocytes or IL1 (a monokine released by activated monocytes) also induced T colony formation in purified T cells. Phorbol myristate acetate (PMA) could replace monocytes in the induction of T colony. Monocytes, IL1, or PMA are known to be crucial requirements for IL2 production by PHA-stimulated T cells. This combined with the fact that IL2 participates in T colony formation suggests that monocytes induce T colony formation through IL2 production.

Clone Cells↗
PubMed1983

Induction of human T colony formation by phorbol myristate acetate.

Phorbol myristate acetate (PMA) is a potent inducer of T colony formation by peripheral blood lymphocytes. A mean cloning efficiency of 0.3% (0.05-0.5%) is obtained with PMA concentrations of 100-1000 ng/ml. PMA-induced T colony formation does not require the presence of monocytes and therefore differs from other mitogens in this respect. Purified T-colony-promoting activity (TCPA) (devoid of phytohaemagglutinin (PHA)) increases PMA-induced T colony numbers and induces T colony formation at low PMA doses (0.01 to 1 ng), concentrations at which no T colonies are detected in the absence of added TCPA. PMA-induced colonies are mainly composed of cells bearing Fc receptors for IgM (54%), which is not the case for colonies obtained with PHA (11%). PMA-induced colony cells do not bind OKT3 and OKT4 monoclonal antibodies, whereas 23% are able to bind OKT8 antibody. These results demonstrate that PMA is a potent inducer of T colony formation and may therefore serve as a useful tool for the study of T-cell differentiation.

Antigens, Surface↗
PubMed1983

Modulation of PHA-induced T colony formation by phorbol myristic acetate.

PMA (10 ng/ml), induced a four-fold increase in PHA-induced T colony formation by peripheral blood lymphocytes (PBL). At lower (0.1-1 ng/ml) and higher concentrations (100-1,000 ng/ml), PMA had an inhibitory effect. The potent co-mitogen effect observed at 10 ng/ml PMA was associated with a strong increase in T colony promoting activity (TCPA) released by PHA stimulated PBL cultured in the presence of PMA (10 ng/ml). PMA at all concentrations exerted an inhibitory effect on T colony formation when PBL were cultured in the presence of PHA and an optimal concentration of exogenous TCPA. PMA was also capable of assuming the essential role played by monocytes in T colony formation. Thus, PMA can fulfil both co-mitogen and monocyte like roles in T colony formation. These activities closely resemble those previously described for interleukin 2 (IL2) production.

Clone Cells↗
PubMed1981

Colonoscopy: a survey of its value in a teaching hospital surgical unit.

A survey has been undertaken of the diagnostic, therapeutic and economic value of colonoscopy in a teaching hospital surgical unit. Provided it is undertaken in conjunction with a good clinical history and double contrast barium enema, colonoscopy provides a high yield of information bearing upon the patient's subsequent management. Therapeutic polypectomy was undertaken in 21% of examinations. Its value in acute colonic disease is discussed, and the importance of training colonoscopists for the future is emphasized.

Adolescent↗
PubMed1980

Sulphate, acid-base, and mineral balances of obese women during weight loss.

Four obese women, each at least 50% above their expected weight for height were maintained in the metabolic unit for 63 days on liquid formula diets of differing protein and calorie content. We made the following findings: 1) When 12 g protein nitrogen was consumed, 1 mEq of acid was excreted in the urine for every 2 mEq of urinary sulphate. 2) On a protein-free diet more acid was excreted in the urine than could be accounted for by oxidation of sulphur to the sulphate which was excreted in the urine. 3) Both increased consumption of protein and a restriction of dietary calories was associated with an increase of urinary acid. 4) Urinary sulphur excretion was closely correlated with nitrogen intake and urinary urea nitrogen excretion. However, on a protein-free diet the ratio of total nitrogen to sulphur in the urine was greater than when 12 g protein nitrogen was consumed. 5) There is some evidence that when total calorie intake was reduced at a level of 12 g protein nitrogen intake, the ratio of urinary urea nitrogen to urinary sulfur decreased. This suggests selective retention of some nonsulphur containing amino acids and/or selective oxidation of sulphur-containing amino acids. 6) In general, urinary calcium and magnesium excretions were depressed both with a decrease in protein consumption and a decrease in caloric intake. 7) The urinary excretions of calcium and magnesium showed a tendency to fall during the 63 days of the experiment. 8) The urinary and fecal phosphorus excretion remained constant during the various metabolic periods of the experiment.

Acid-Base Equilibrium↗