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Biomedical subjects

C Fournier

Publications and source records attributed to C Fournier.

At least 145 records · Page 8Linked to original sources
PubMed1991

[Role of collagen conformation in type II anticollagen immunity in rheumatoid polyarthritis].

Type II anticollagen (CII) autoimmunity is a frequently reported, but non-specific, phenomenon in rheumatoid arthritis (RA). The authors show that in 88 sera samples from patients suffering from RA, the incidence of antibodies targeted against endogenous human CII was the same as that found for 149 control blood donors (14.8% versus 11.4%). However, a significant difference was found for the incidence of antibodies targeted against the alpha-chains of CII (26.1% versus 6.0%, p less than 0.001). As a result of investigating the specificity of the anti-CII antibodies in greater detail by means of an immunoprinting of the CII peptide fragments obtained after splitting the molecule by cyanogen bromide, the authors have demonstrated that the largest CII peptides (CB10 and CB11) were better recognized than the smaller peptides (CB8, CB9.7), with no significant difference between PR and control plasmas. Using competitive methods, evidence was obtained in support of heterogeneous recognition by the anti-CII antibodies: some recognize conformational determinants only, whereas others are targeted against the primary sequences of the alpha-1 (II) chain.

Antibody Diversity↗
PubMed1991

[Coronary spasm and diffuse coronary vasoconstriction responsible for transient left ventricular insufficiency].

A 52 year old patient presenting with spontaneous anginal chest pain for 4 days was admitted to hospital for a more intense and prolonged chest pain associated with signs of left ventricular failure (gallop, pulmonary crepitations, hypoxemia). Coronary angiography showed marked septal hypokinesia and spontaneous localised spasm of the left anterior descending and marginal arteries with a variable degree of luminal narrowing of the other segments of these two arteries and of the right coronary artery. These changes regressed after intracoronary injection of molsidomine. The signs of left ventricular failure disappeared in 48 hours. The wall motion abnormality, monitored by 2D echocardiography, regressed slowly over 3 days. On the other hand, the electrocardiogram, which showed anterior wall subendocardial ischaemia with prolongation of the QTc interval during the spasm, remained abnormal for a long time. Therefore, in the absence of organic heart disease, coronary spasms associated with vasoconstriction can induce a sufficiently severe and durable alteration of left ventricular function to create clinical signs of cardiac failure and profound and prolonged ST-T wave changes on the electrocardiogram.

Coronary Angiography↗
PubMed1990

T cell regulation of collagen-induced arthritis in mice. I. Isolation of Type II collagen-reactive T cell hybridomas with specific cytotoxic function.

After immunization with native type II collagen (CII), susceptible strains of mice (H-2q) develop a polyarthritis that mimics rheumatoid arthritis. Although the underlying mechanisms are still undefined, T cells and particularly CD4+ lymphocytes seem to play a crucial role in the initiation of collagen-induced arthritis. To investigate whether CD8+ cells may participate in the pathogenesis of the disease, we have generated lines and clones of cytotoxic T cell hybridomas reactive to CII by fusion of lymph node and spleen cells from bovine native CII-primed C3H.Q (H-2q) mice and the AKR-derived thymoma cell line BW 5147. Clones were selected for their ability to lyse syngeneic macrophages pulsed with bovine native CII in an Ag-dependent manner. The two hybrid clones that were characterized, exhibited cell surface phenotypes of cytotoxic cells and reacted with CII purified from various species. However, each of them recognized different determinants on the CII molecule. P3G8 clone was specific for an epitope shared by CII and type XI collagen, whereas P2D9 clone reacted with CII and type IX collagen. Both hybridomas recognized CII-pulsed targets in association with H-2Kq molecules. These data indicate that the two CII-specific cytotoxic clones recognize different epitopes that are shared by other articular collagens and will allow us to test their influence on the development of arthritis in vivo.

Animals↗
PubMed1990

Arthritogenicity of minor cartilage collagens (types IX and XI) in mice.

Native type II collagen, the major cartilage collagen, is immunogenic and arthritogenic in rodents. To investigate whether minor cartilage collagens are arthritogenic, we immunized DBA/1 mice with the pepsin-soluble fractions of type IX or type XI collagen emulsified in Freund's complete adjuvant. Both collagens were arthritogenic in DBA/1 mice after only 1 injection. However, the incidence of the polyarthritis was lower and the severity was lesser than with that induced by bovine type II collagen, even when a booster injection was administered. All mice developed a humoral response to the immunizing antigen, without any relationship to the arthritic status. Interestingly, competition experiments showed that antibodies raised against type XI collagen also bound with high avidity to type II collagen. In contrast, sera from type IX collagen-immunized mice did not react with either type II or type XI collagen. We conclude that types IX and XI minor cartilage collagens are both arthritogenic and immunogenic in DBA/1 mice. Whether the recognition of epitopes common to different collagens is relevant to the articular pathology remains to be elucidated.

Animals↗
PubMed1990

In vivo beneficial effects of cyclosporin A and 1,25-dihydroxyvitamin D3 on the induction of experimental autoimmune thyroiditis.

In a recent work, we provided evidence that the in vitro inhibitory effect of cyclosporin A (CsA) was potentiated by the addition of another immunosuppressive molecule, the 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). In the present study, we investigated the in vivo influence of the association of both drugs administered at infratherapeutic doses, using an experimental model of autoimmune thyroiditis in CBA mice. Treatment regimen of the animals was initiated at priming with thyroglobulin (Tg) and consisted of daily administration of CsA (10 and 20 mg/kg/day, intragastrically) and/or 1,25(OH)2D3 (0.1 and 0.2 microgram/kg/day, ip) for 21 days. Control mice that were given a placebo preparation orally and the vehicle of vitamin D3 metabolite ip developed a severe disease as assessed by histological examination on Day 28 postimmunization and detection of circulating anti-Tg antibodies. Treatment with either drug administered alone at the doses mentioned above did not affect the incidence of thyroiditis and only reduced by up to 26% the severity of histological lesions. In contrast, the mice treated simultaneously with both drugs exhibited a lower incidence of thyroid pathology and developed a significantly milder disease (P less than 0.001) as compared to controls. However, there was no alteration in the levels of anti-Tg antibodies. This in vivo beneficial effect of low doses of CsA and 1,25(OH)2D3 was not due to an accumulation of CsA in the blood of treated mice since the levels of CsA were similar, regardless of the administration of 1,25(OH)2D3. Our data suggest that these two immunomodulatory agents used together at low doses may be an effective therapy of autoimmune disorders with fewer side effects.

Animals↗
PubMed1990

The concept of corticosteroid cataractogenic factor revisited.

Formation of posterior subcapsular cataracts is a known complication of systemic corticosteroid therapy. However, the relation between steroid dosage, cumulative dose and type of steroid on one hand and the subsequent formation of cataract on the other is unclear. We carried out a study to determine the incidence of posterior subcapsular cataracts in 64 children who had undergone renal transplantation and to attempt to determine what factors were associated with cataract formation. Cataracts were detected in 17 (26%) of the patients. The steroid dosage, cumulative dose and duration of therapy were not associated with cataract formation. There was a significant difference in the distribution of HLA-CW3 antigen between the patients with cataracts and those without cataracts. The reason for the link between corticosteroid therapy and formation of posterior subcapsular cataracts remains unclear.

Adolescent↗
PubMed1990

Stable circadian mechanisms of toxicity of two platinum analogs (cisplatin and carboplatin) despite repeated dosages in mice.

The toxicities and tissue uptake of cisplatin (CDDP) and carboplatin (CBDCA) vary largely according to the time of injection of a single dose. Repeated dosages may alter the mechanisms involved with such circadian-dependent toxicity. Weekly i.v. injections of CDDP (5 mg/kg) or CBDCA (50 mg/kg) were given over 2 months to 288 male B6D2F1 mice standardized by an alternation of 12 hr of light and 12 hr of darkness at any one of three circadian dosing times (0, 8 or 16 hr after light onset--HALO). Survival; body weight; complete blood cell counts; histologic lesions in kidney, liver, spleen, bone marrow and intestinal tract; platinum concentration in kidney, spleen and colon were determined every 2 weeks throughout treatment. Thrombocytopenia was 10-fold larger following CBDCA as compared with CDDP. Severe bone marrow necrosis was cumulative following CDDP, but reversible following CBDCA. Leukopenia and bone marrow lesions were, respectively, half as severe following the dosing of either drug at 16 HALO compared with 0 or 8 HALO. Cortical tubular necrosis was observed in CDDP-treated mice. It was cumulative and half as extensive after drug dosing at 16 HALO, as compared with 0 or 8 HALO (P less than or equal to .05). Total Pt accumulation in all three tissues was 3- to 4-fold higher following repeated dosages of CDDP as compared with CBDCA. Tissue Pt uptake was halved after CDDP or CBDCA dosing at 16 HALO as compared with 8 HALO (P less than or equal to .01). Dosing either Pt complex at the appropriate time is even more critical if administrations are to be repeated. Mechanisms appear to involve the circadian rhythm-dependent ability of target tissues to take up the drug.

Animals↗
PubMed1989

Circadian rhythm in toxicities and tissue uptake of 1,2-diamminocyclohexane(trans-1)oxalatoplatinum(II) in mice.

Mechanisms involved in the circadian rhythm in murine tolerance for the new platinum analogue, 1,2-diamminocyclohexane(trans-1)oxalatoplatinum(II) (1-OHP) were sought in 404 male C57BL/6 x DBA/2 F1 mice standardized by 12 h light-12 h dark. A potentially lethal dose of 1-OHP (17 mg/kg i.v.) resulted in 76% long-term survival at 15 h after light onset (HALO) (activity span) as compared to 24% after treatment at 7 HALO (rest span) (chi 2 21.3; P less than 0.001). A total of 204 mice received the same dose of 1-OHP at one of three circadian stages (0, 8, or 16 HALO). No renal toxicity was encountered. Bone marrow and jejunal villi constituted the chief targets of 1-OHP toxicity at this dosage and schedule. Hematological tolerance as gauged by leukocyte counts was optimal when the drug was given at 16 HALO (P from analysis of variance, less than 0.001). Jejunal lesions were less severe after 1-OHP dosing at 16 HALO as compared to 8 HALO (P less than 0.001). Total platinum concentrations were determined in 18 tissues 24 h after 1-OHP dosing. The highest levels of platinum were found in the spleen on day 1 as well as on day 5 following 1-OHP treatment. Despite the fact that the highest platinum concentrations in tissues usually corresponded to drug dosing at 8 HALO, no correlation was documented between such variables and tissue toxicity. Tissue pharmacokinetics of 1-OHP contribute only in part if at all to the circadian rhythm in hematological and jejunal toxicity of this drug.

Animals↗
PubMed1989

1,25-dihydroxyvitamin D3 potentiates the in vitro inhibitory effects of cyclosporin A on T cells from rheumatoid arthritis patients.

Treatment of rheumatoid arthritis (RA) with cyclosporin A (CsA) has been successful, but the adverse effects of the drug have limited its use. We investigated the capacity of another immunosuppressive agent, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], to augment the effects of CsA on in vitro T cell functions. Exposure of CD4+ cells from RA patients or from normal subjects to either molecule alone resulted in a dose-dependent inhibition of phytohemagglutinin stimulation and interleukin-2 (IL-2) production that was more pronounced in cells from RA patients than in cells from normal subjects. Moreover, the action of CsA and 1,25(OH)2D3 on RA patient T cell functions in vitro was synergistic. Thus, in the presence of the vitamin D3 metabolite, only one-hundredth the concentration of CsA was required to produce the same effect on IL-2 production as that produced by CsA alone. IL-2 receptor expression was also reduced by the addition of both drugs. In contrast, IL-1 production by RA monocytes was not affected by CsA and 1,25(OH)2D3, either together or alone, and addition of IL-1 did not restore the ability of CD4+ cells from RA patients to secrete IL-2. Exogenous IL-2 reversed a large part of the inhibitory effect induced by both CsA and 1,25(OH)2D3, indicating that the immunosuppressive properties of these agents are mediated by the inhibition of IL-2 secretion. This synergy between 2 molecules that are biochemically very different suggests the existence of one or several sites of interaction that take place during the early stages of T cell activation.

Arthritis, Rheumatoid↗
PubMed1989

Comparative study of intravenous and intraarterial cis-platinum on intratumoral platinum concentration in carcinoma of the cervix.

In order to define the influence of intraarterial administration of cis-platinum in tumors of the cervix, a preliminary crossover study was performed to measure and compare the intratumoral concentrations (ITC) of platinum obtained respectively after intravenous (iv) and intraarterial (ia) (both bilateral hypogastric arteries) injection. The results in nine patients demonstrate that higher (P = 0.05) intratumoral concentrations are obtained after intraarterial injection of cis-platinum: 10; 3.7-23.7 ng Pt/mg of dry tissue after ia (median; range) 6.9; 4.1-23.6 ng Pt/mg tissue after iv. This difference is probably too small to be of clinical significance and a comparative clinical trial does not seem to be warranted. The results also show a large intersubject variation in intratumoral platinum concentration which are reproducible in patients whatever route of administration is used. Thus the observed differences in ITC are more related to the variability of the tumor properties than to the route of administration.

Adult↗
PubMed1989

Comparison of the efficacy of propranolol and amiodarone in suppressing ventricular arrhythmias following myocardial infarction.

The purpose of this prospective randomized trial was to compare the efficacy of propranolol and amiodarone in suppressing ventricular arrhythmias during the first 6 months following myocardial infarction (MI). 97 patients were treated with either amiodarone (n = 48) or propranolol (n = 49) starting on the 9th day following MI. Holter monitoring was carried out on four occasions: on D7, D21, D90 and D180. There was no statistical difference in the incidence of 'major' arrhythmias (an average of at least 10 ventricular premature complexes (VPCs) h-1, multiform or paired VPCs or runs) between the two groups on D7. A significant difference in favour of amiodarone became apparent at D180 (P = 0.04). Patients were also classified according to whether treatment failed or was successful. 'Success' was recorded when arrhythmias remained minor or became minor (less than 10 uniform VPCs h-1) and 'failure' when arrhythmias remained major or became major, or when patients were withdrawn because of side-effects, or lost to follow-up. The difference remained in favour of amiodarone (P = 0.03 at D21; P = 0.05 at D90; P = 0.06 at D180). Evaluation of the percentage reduction in the number of VPCs at D21, D90 or D180 compared with D7 showed superiority of amiodarone at D90 (P less than 0.01) and D180 (P less than 0.04). In this study, the overall effect of amiodarone on ventricular arrhythmias following MI was shown to be superior to that of propranolol.

Aged↗
PubMed1989

Polyarthritis in MRL-lpr/lpr mice: mouse type II collagen is antigenic but not arthritogenic.

In addition to a lupus-like syndrome and massive T cell proliferation, MRL-lpr/lpr(MRL/l) mice develop an arthritic process very similar serologically and histologically to human rheumatoid arthritis (RA). Recently, we have developed in DBA/1 mice an experimental model of autoimmune arthritis (EAA) which shares clinical features with RA, by injecting homologous type II collagen (CII). In order to investigate the possible relationship between the spontaneous polyarthritis of MRL/l mice and collagen induced EAA, we immunized MRL/l mice with mouse (M) CII. Our findings revealed that the injection of 100 micrograms M-CII in young or old MRL/l mice did not modify the articular pathology which spontaneously develops in non-injected mice. Circulating autoantibodies to native M-CII were found in the sera of immunized young mice but were not detected in non injected or immunized old mice. Conversely, denatured alpha 1 (II) chains or CB peptides derived from M-CII were recognized by most of the MRL/l sera whether mice had been immunized or not. The incidence of positive sera as well as the intensity of the response evaluated by Western blot analysis increased with the age of the mice. Taken together, our data suggest that, even if the injection of homologous CII in MRL/l mice may accelerate the onset of joint pathology, the spontaneous disease arises independently of an autoimmune response against native CII.

Animals↗
PubMed1989

Pattern of humoral reactivity to type II collagen in rheumatoid arthritis.

Humoral immunity directed against type II collagen (CII) is a common although not specific feature of rheumatoid arthritis (RA). We have shown that 10 to 15% of the sera either from RA patients (n = 88) or from healthy controls (n = 149) reacted with native human CII. Conversely, autoantibodies to the alpha-1 (II) chains were significantly more frequent in the RA group (26.1% versus 6.0%, P<0.001), suggestingthatdenaturedCII may bean autoantigenin RA. Thus, human CII was cleaved with cyanogen bromide (CB), and immunoblotting techniques were performed on 19 RA and 21 normal sera. Among the four major CB peptides, CB10 and CB11 were recognized by most of the sera tested without distinction between normal or RA sera. Inhibition experiments using an ELISA have shown that: (i) antibodies to the native CII molecule did not cross-react with those recognizing the CB peptides, and vice-versa; (ii) the binding of the sera to native CII was partially inhibited by pre-incubation with alpha-1 (II) chains, and vice-versa; (iii) pre-incubation of the sera with CB peptides partially blocked the binding to alpha-1 (II) chains, whereas pre-incubation of the sera with alpha-1 (II) chains totally inhibited the reactivity against CB peptides; and (iv) a substantial proportion of the epitopes recognized by anti-CII autoantibodies was neither species specific nor type specific. Taken together, these findings reveal the existence of several populations of anti-CII autoantibodies: some antibodies react exclusively with conformational determinants of the CII molecule, and others are directed towards linear structures of alpha-1 (II) chains.

Animals↗
PubMed1989

[Comparative efficacy of amiodarone and propranolol on ventricular arrhythmia in the post-infarction period].

Beta-blockers are known to be effective against post-infarction ventricular arrhythmias and amiodarone has recently been shown to have this property. The purpose of this prospective randomized study was to compare the effects of beta-blockers and amiodarone during the first 6 months following infarction. Nine days after the onset of myocardial infarction, 97 patients were put on either amiodarone (48) or propranolol (49). Holter monitoring was performed on four occasions: on the 7th post-infarction day (baseline), then on the 21st, 90th and 180th days (under treatment). On D7 the two groups were similar in age, sex, risk factors, medical history, characteristics of the infarction and type of arrhythmia. For result analysis purposes the patients were divided into two categories depending on whether their arrhythmia was "moderate" (less than 10 monomorphous and isolated ventricular extrasystoles per hour) or "severe" (at least 10 ventricular extrasystoles per hour, or polymorphous or repetitive ventricular extrasystoles). Concerning the frequency of "severe" arrhythmia, there was no statistical difference between the two treatment groups on D7 (p = 0.53), but differences in favour of amiodarone became increasingly important during the study (p = 0.08 on D21; p = 0.07 on D90; p = 0.04 on D180).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗