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Biomedical subjects

M Renoux

Publications and source records attributed to M Renoux.

At least 55 records · Page 3Linked to original sources
PubMed1989

Imuthiol influences on cytotoxic T cells and NK activity in +/+ and athymic nude BALB/c mice.

The effects of imuthiol (sodium ditiocarb, DTC) on the expression of cytotoxic responses (CTL) and natural killer (NK) activity were evaluated in aged and young euthymic mice, and in nu/nu BALB/c mice. Imuthiol generated CTL and concomitantly reduced NK activity in nu/nu mice, suggesting that the agent can generate T cells in athymic nude animals. Treatment for up to 4 months augmented spleen NK and CTL activities in young or aged euthymic mice, but the generation of CTL in old animals was increased by long-term treatments better than by a single injection. The capacity of imuthiol to activate specific and nonspecific cytotoxic functions in euthymic mice may contribute to enhancement of resistance in vivo against transformed cells after treatment with this agent.

Adjuvants, Immunologic↗
PubMed1988

Histamine release from rat peritoneal mast cells by kinin antagonists.

Kinins are known to be potent releasers of histamine. In the present study, the B2 antagonist analogues of bradykinin (BK) and kallidin (KD): [( Thi6,9,D-Phe8]KD, [Thi5,8,D-Phe7]BK) were also found to be potent releasers of histamine from rat mast cells and not to exert any antagonistic effect. Similarly, two B1 receptor antagonists, des-Arg10-[Leu9]KD and des-Arg9-[Leu8]BK, were shown to promote histamine release and acted only as agonists. The order of potency of these analogues was the following: [Thi6,9,D-Phe8]KD greater than [Thi5,8,D-Phe7]BK greater than des-Arg10- [Leu9]KD greater than des-Arg9-[Leu8]BK. The high activity of some of these compounds suggests that (1) the potency of kinins for histamine release from rat mast cells not only increases in parallel with the number of positively charged amino acids (Lys, Arg) but also, because of others factors such as peptide conformation, receptor binding affinity or receptor accessibility, (2) the histamine release by kinins is either a non-specific effect not mediated by receptors or, if receptors are involved, these sites may be different from other kinin receptors (i.e. B1 or B2).

Animals↗
PubMed1988

Immunologic indices in myelodysplastic syndromes.

Immunocompetence was evaluated in 36 untreated and noninfected patients affected with myelodysplastic syndromes (MDS). T-cell number and activity were evaluated by counts of total T-cells and T-lymphocyte subsets, and by measure of DNA synthesis in response to phytohemagglutinin and Concanavalin A. B-cells were evaluated as surface immunoglobulin- (SIg+) bearing cells and by serum immunoglobulin levels. Granulocyte activities were evaluated by responses to chemotaxis and to nitroblue tetrazolium test. Complement activity was measured by classic hemolytic complement assay. In addition, circulating immune complexes were detected in serum. MDS were associated with a significant decrease in the absolute numbers of total T (E-rosetting and T3+) cells, T4+, and T8+ cells and a dramatic decrease of the responses to Concanavalin A. An impairment of either chemotaxis or of nitroblue tetrazolium (NBT) test was frequently encountered. An increase in the levels of IgG or IgA was also a frequent feature. The findings reveal that all patients with a high degree of T-cell impairment have refractory anemia associated with an excess of medullary blast cells. All in all, the data suggest that the counts of the absolute number of cells bearing the T3 and T8 phenotypes could be of prognostic value: the higher the number, the better the patient's survival.

Adult↗
PubMed1988

Study of histamine release induced by acute administration of antitumor agents in dogs.

The effects of eight antitumoral drugs known to cause anaphylactoid side effects in clinical use were studied in dogs. Blood pressure, heart rate, and blood and plasma histamine levels were monitored. L-asparaginase, methotrexate, 5-fluorouracil, bleomycin, and cisplatin had no effect on these parameters. Doxorubicin, Vehem (teniposide), and Vepeside (etoposide) induced hypotension, tachycardia, and a rise in histamine levels. In the cases of Vehem and Vepeside, the excipient (respectively, cremophor EL and tween 80) induced the same effects. These agents, like elliptinium, which had been previously studied, induce nonspecific histamine release--unlike the other drugs studied. The mechanism of clinically observed anaphylactoid side effects is discussed in the light of these findings.

Anaphylaxis↗
PubMed1988

Serial study of T-lymphocyte subsets in women during very early pregnancy.

The aim of this serial study was to define variations in T-lymphocyte populations during the first weeks of pregnancy. Results obtained with 14 women pregnant after artificial insemination show that the CD4+ population decreased significantly as soon as the fourth week. This decrease was concomitant with the HCG peak and could be compatible with certain immunological mechanisms participating in tolerance to the fetal graft.

Adult↗
PubMed1988

Immunopharmacology and immunotoxicity of zinc diethyldithiocarbamate.

Zinc is essential for the functions of the immune system, and sodium diethyldithiocarbamate (imuthiol) restores and regulates the numbers and activities of cells of the T-cell lineage. The combination of both elements was therefore tested for immune enhancement and immunotoxicity. The data presented herein show that the administration of zinc diethyldithiocarbamate was devoid of immunoenhancing influence on the responses to T-cell mitogens, and exerted a cytocidal effect on spleen lymphocytes.

Adjuvants, Immunologic↗
PubMed1988

Brain neocortex and imuthiol regulate the expression of MHC antigens on mouse T lymphocytes.

The induction of T-cell responses involves the recognition of extrinsic antigens in association with antigens of the major histocompatibility complex (MHC). The present results demonstrate that the lateralized control exerted by the brain neocortex on T-cell activities extends to the expression of MHC antigens, yet differently on spleen or lymph node T cells. This study also shows that the neocortex influences the changes induced by an immunopotentiator, sodium diethyldithiocarbamate (imuthiol), on the MHC antigen content on mouse T cell-surface.

Animals↗
PubMed1988

Discordant heart xenografts in the rat. Additional effect of plasma exchange and cyclosporine, cyclophosphamide, or splenectomy in delaying hyperacute rejection.

Natural antidonor antibodies are known to play a prominent role in hyperacute xenograft rejection. The aim of this work was to devise an experimental protocol to prolong the survival time of guinea pig heart xenografts transplanted into rats. A technique of continuous plasma exchange adapted to small animals was used to remove the natural cytotoxic antibodies from the recipient prior to the transplantation. In some experiments, cyclosporine (CsA), cyclophosphamide (CY), or splenectomy were associated with the plasma exchange. In this highly discordant xenogenic donor-recipient combination, the mean graft survival time in nontreated rats was 16 min. When an exchange of 1.5 plasma volume was performed 24 hr before the transplantation, no prolongation of the graft survival time was observed. When CsA, CY, or splenectomy were associated with the plasma exchange, the graft survival time was significantly increased by more than 2500% (up to 418 min with CsA). When used isolately, none of these 3 immunosuppressive methods was able to prolong the graft survival time. Natural cytotoxic antibodies were monitored by a complement-mediated cytotoxicity assay. After a plasma exchange, the titers decreased from 1:16-1:32 to 1:1-1:2. When no immunosuppressive method was associated with the plasma exchange, the antibodies returned to their initial level within the 24 hr that preceded the transplantation, and the graft was rejected as in nontreated animals. When an immunosuppressive method was associated with the plasma exchange, and particularly in the case of CsA, the titers remained low, and the hyperacute rejection was delayed. Therefore, it can be concluded that plasma exchanges, associated with CsA, are an efficient experimental protocol in the rat to increase the survival time of guinea pig heart xenografts. The effect of the treatment is correlated with the decrease in natural cytotoxic antidonor antibodies.

Animals↗
PubMed1987

Age as the main prognostic factor in adult aggressive non-Hodgkin's lymphoma.

From 1975 to 1983, 73 patients with aggressive non-Hodgkin's lymphoma were treated with a first-generation program including Adriamycin, VM 26, cyclophosphamide, and prednisone. Thirty-nine patients were under 60 years of age, and 34 were 60 years or older. The clinical and histologic characteristics of the two groups were similar. Using either univariate or multivariate analysis, age appeared as the only prognostic factor. Patients under 60 had a median survival of 48 months, with a five-year survival rate of 47 percent and a five-year disease-free survival rate for complete-remission patients of 72 percent. Patients 60 years or older had a median survival of 18 months with a five-year survival rate of 18 percent and a five-year disease-free survival rate for complete-remission patients of 24 percent. These highly significant differences were related to a non-significantly decreased complete-remission rate and a significantly higher relapse rate in elderly patients. Since patient selection according to age could play a role in the results achieved with intensive chemotherapy programs, randomized trials comparing the various chemotherapy programs for aggressive non-Hodgkin's lymphoma are warranted.

Adolescent↗
PubMed1987

[Isotypes of rheumatoid factors and cellular immunity anomalies in rheumatoid polyarthritis. Apropos of 61 cases].

In 61 patients with rheumatoid polyarthritis, we studied the rheumatoid factors isotypes, class IgM, IgG, IgA and the abnormalities of the ratio CD4/CD8 (lymphocytes with membrane phenotype "helper"/lymphocytes with membrane phenotype "suppressor") determined by monoclonal antibodies. We found a statistically significant increase of the rate of IgM rheumatoid factors (p less than 0.0001), IgG (p less than 0.004), IgA (p less than 0.008), in patients with rheumatoid polyarthritis whose ratio exceeded that of the control population. On the other hand, the percentage of rheumatoid factors detected by agglutination was not significantly increased in this group. This increase seemed linked to a specific abnormality of the control of lymphocytes B which synthesize rheumatoid factors.

Adult↗
PubMed1987

[Immunological data furnished by alveolar lavage in bronchopulmonary tumor pathology].

Alveolar lavage is a simple technique giving access to the inner lung. The object of this study is to assess the place of alveolar lavage in pulmonary tumours in man. The systemic changes in the immune system are not touched upon, nor the search for tumour cells. The supernatant has revealed greater than normal levels of carcino-embryonic antigen in primary tumours and metastases. The immunoglobulins (IgE, IgA) are increased also. The ready collection of the alveolar macrophages (MA) around the tumour permits a study of their functional capacity: chemotaxis, phagocytosis, cytotoxicity. The chemotaxis of MA breaks down around a primary cancer even though it is not changed in pulmonary metastases. The data in the literature concerning the capacity for phagocytosis and of anti-tumour cytotoxicity are still fragmentary. Increasing the tumoricidal properties of MA is a prospect for future. Alveolar lavage is an additional diagnostic method. It allows for a progressive scrutiny of the local immunological response in broncho-pulmonary tumours.

Bronchial Neoplasms↗
PubMed1987

[Rheumatoid factors. Isotypes and severity of rheumatoid polyarthritis].

The immuno-enzymatic method permits the separate study of rheumatoid factors (RF): IgM as well as IgG, IgA, IgE, IgD. In 43 patients with rheumatoid polyarthritis (RP), classic or definite, we have studied the correlations between the various parameters of articular and extraarticular activity of RP and the levels of each isotype of RF. A statistically significant correlation of the articular activity was found with RF IgG (p less than 0.01), RF IgA (p less than 0.01). As compared to RP without rheumatoid nodule, RPs with rheumatoid nodules presented a level of RF IgM (p less than 0.05), RF IgG, IgA, IgE (p less than 0.01) which was statistically higher; a statistically significant correlation was found between haptoglobin levels and those of RF IgG (p less than 0.01). A negative correlation, statistically significant, was found between CH 50 and the levels of RF IgM. This study confirms previous studies which were carried out with an immuno-enzymatic method of detection of RF isotypes.

Arthritis, Rheumatoid↗
PubMed1986

Early changes in immune parameters induced by an acute nonantigenic inflammation in mouse: influence of imuthiol.

Calcium pyrophosphate (CaPP)-induced pleurisy, may represent one of the simplest expressions of inflammation in that the irritant is a non-diffusible, non-antigenic and non-pyrogenic agent. Spleen or lymph node T or B cell numbers and activities, as well as NK activity, were modified at distance by CaPP-pleurisy. An intense increase in blood polymorphonuclear cells was also triggered by the inflammatory process. Treatment with imuthiol (sodium diethyldithiocarbamate), an agent known to be active on the T-cell lineage, restored towards control values the inflammatory response and tended to normalize white blood cell percentages altered by the inflammatory process. The findings suggest imuthiol could be employed as a virtually nontoxic and non-steroidal anti-inflammatory agent.

Animals↗
PubMed1986

Effects of the ionophore grisorixin on myocardial function and metabolism in isolated perfused working rat heart under normoxic and hypoxic conditions.

The effects of grisorixin, a monocarboxylic ionophore, were studied on isolated working rat hearts perfused with a suspension of washed pig erythrocytes (10% hematocrit). Grisorixin (2.5 microM) induced a transient stimulation of heart work, maximal at 5 min, expressed by an increase in heart rate (+21%) and aortic flow (+17%) and by an increase in coronary flow, maximal at 10 min (+47%). Concomitantly, myocardial Vo2 was slightly enhanced and the myocardial creatine phosphate level dropped (2 min). The lactate production increased by 82% (5 min) then dropped to the control value (10 min) and increased again till the 45th min (+211%), indicating a cardiac metabolic drift towards anaerobic glycolysis due to partial inhibition of the oxidative metabolism. Owing to its properties as an ionophore, grisorixin also induced a strong and rapid increase of potassium concentration in the perfusate and a decrease of sodium. Grisorixin was tested on hearts submitted to 20 min of hypoxic conditions. The hypoxia was rather mild and induced only very slight modifications of the ultrastructure. In the control series, heart rate and aortic flow decreased regularly while coronary flow and lactate production increased. Upon reoxygenation, the heart performances were rapidly restored. Grisorixin was administered according to four different protocols. When injected at the onset of hypoxia or 5 min later, it was able to maintain the aortic flow during the first minutes and induce a higher coronary dilation. These beneficial effects were short-lasting and no deleterious effects were found on the ultrastructure of hearts subjected to grisorixin whether after hypoxia or after reoxygenation.

Animals↗