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O Meyer

Publications and source records attributed to O Meyer.

At least 181 records · Page 10Linked to original sources
PubMed1995

Anti-vascular endothelial cell antibodies (AECA): comparison of two assay methods and clinical applications.

Vascular endothelial cells may be a target for autoantibodies (AECAs) against membrane antigens that are constitutively expressed, induced or bound to their surface. To test this hypothesis, we used an enzyme-linked immunosorbent assay (ELISA) with two types of human endothelial cells as the substrate, i.e., human umbilical cord vein endothelial cells (HUVECs) or the hybrid cell line EAhy-926 obtained by fusion of HUVECs with the bronchial carcinoma cell line A549. A comparative functional study of these two cell types demonstrated that EAhy-926 cells produced only small amounts of VIII von Willebrand factor and tissular factor, did not contain Weibel Palade bodies visible under the electron microscope, and expressed ICAM-1 and selectin E in levels of no more than 15% of those expressed by human umbilical cord vein endothelial cells both after stimulation by bacterial lipopolysaccharide and under basal conditions. However, the two assay methods yielded similar IgG AECA titers when used on sera from patients with rheumatoid vasculitis or antiphospholipid syndrome. These antibodies did not exhibit cytotoxicity for cord vein or EAhy-926 cells. They were not specific for endothelium, since their activity decreased by a mean of 40% after incubation of sera with the epithelial cell line A549. A cross-sectional study of 565 sera demonstrated that anti-vascular IgG and IgM AECAs reactive with EAhy-926 cells occurred mainly in patients with dermatomyositis (IgG, 58%; IgM, 22%), systemic scleroderma (IgG, 48%; IgM, 18%), primary Sjögren's syndrome (IgG, 44%; IgM, 12%) and secondary and primary systemic vasculitides (IgG, 38%; IgM, 18%) including Wegener's granulomatosis. A longitudinal study in patients with Wegener's granulomatosis showed that AECAS were predictive of disease activity.

Antibodies↗
PubMed1994

Metabolic relationship between the CO dehydrogenase molybdenum cofactor and the excretion of urothione by Hydrogenophaga pseudoflava.

Urothione was isolated as an excretion product of Hydrogenophaga pseudoflava and other bacteria at amounts approaching 253 micrograms/l of culture corresponding to 44 micrograms/g bacterial dry mass. The compound was identified as urothione by co-chromatography with urothione isolated from human urine, its characteristic ultraviolet and visible absorption spectra, oxidation to pterin-6-carboxylic-7-sulfonic acid by alkaline permanganate, 1H-NMR spectroscopy, double-quantum-filtered Fourier-transform 1H correlated spectroscopy, circular-dichroism spectroscopy and mass spectroscopy. A metabolic relationship between urothione and the carbon monoxide dehydrogenase molybdenum cofactor was suggested by a 1.1:0.5 molar ratio between urothione excreted and degradation of carbon monoxide dehydrogenase, a coincidence of urothione excretion and induction of carbon monoxide dehydrogenase with different species of carboxidotrophic bacteria, a structural relationship between molybdopterin cytosine dinucleotide of the carbon monoxide dehydrogenase molybdenum cofactor and urothione, and the demonstrated conversion of the carbon monoxide dehydrogenase molybdenum cofactor to urothione in vitro. A pathway for the conversion of the H. pseudoflava carbon monoxide dehydrogenase molybdenum cofactor to urothione has been proposed which involves molybdopterin cytosine dinucleotide, molybdopterin, phospho-norurothione and norurothione.

Aldehyde Oxidoreductases↗
PubMed1994

The 86-kDa subunit of autoantigen Ku is a somatostatin receptor regulating protein phosphatase-2A activity.

We previously reported the immunopurification of a somatostatin receptor from the human tumoral gastric cell HGT1 using the monoclonal antibody 30F3 (Reyl-Desmars, F., Le Roux, S., Linard, C., Benkouka, F., and Lewin, M. J. M. (1989) J. Biol. Chem. 264, 18789-18795). Screening of a lambda gt11 HGT1-cDNA library with 30F3 led us to isolate a cDNA encoding an 86-kDa polypeptide displaying 100% structural identity with the 86-kDa subunit (p86-Ku) of the Ku autoantigen. Recombinant p86 expressed in Escherichia coli cross-reacted with 30F3 and specifically bound [125I-Tyr11]somatstatin-14. Binding was totally displaced by somatostatin-14, somatostatin-28, and SMS 201-995, with IC50 values of 0.7, 1.0, and 1.2 nM, respectively. In a search for a biological effect associated with binding, we purified a 36-kDa, okadaic acid-sensitive phosphatase (protein phosphatase-2A (PP2A)) from rat gastric cytosol. PP2A catalyzed 32P release from p34cdc2-phosphorylated histone H1. However, PP2A-induced 32P release was concentration dependently inhibited by recombinant p86-Ku, with a decrease in maximal velocity without a change in Km. Steric exclusion high pressure chromatography indicated that the inhibition resulted from direct interaction of the enzyme with p86-Ku. Furthermore, it was antagonized by increased concentrations of somatostatin-14 and prevented by preincubating p86-Ku with 30F3. Given the key role played by PP2A in cell cycle regulation, the current findings suggest that p86-Ku could be a physiological target of somatostatin antiproliferative action.

Animals↗
PubMed1994

Elevated serum levels of interleukin-1 receptor antagonist in polymyositis/dermatomyositis. A biologic marker of disease activity with a possible role in the lack of acute-phase protein response.

OBJECTIVE: To determine whether the lack of acute-phase protein (APP) response in numerous patients with polymyositis/dermatomyositis (PM/DM) is related to an imbalance between cytokines and cytokine inhibitors. METHODS: Levels of C-reactive protein (CRP), interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), IL-6, IL-1 receptor antagonist (IL-1ra), TNF soluble receptor 55 kd (sTNFR 55 kd), and sTNFR 75 kd were tested in the serum of 15 patients with PM/DM, 14 patients with spondylarthropathies (SPA), and 12 healthy blood donors. Serum IL-1 beta, TNF alpha, IL-6, IL-1ra, sTNFR were measured by specific immunoassays. RESULTS: Serum levels of CRP were lower in PM/DM patients than in SPA patients. Normal or slightly elevated CRP values were found in 10 of the 15 PM/DM patients, 7 of whom had active myositis. Serum IL-6 levels were significantly higher in SPA patients than in PM/DM patients, whereas serum IL-1ra and sTNFR levels were significantly higher in PM/DM than in SPA patients. IL-1ra levels were particularly elevated in patients with active myositis and decreased in response to treatment. CONCLUSION: These differences in cytokine levels, particularly IL-1ra, between PM/DM and SPA patients are indicative of distinct pathogenic mechanisms. High levels of IL-1ra may account for the weak APP response in some PM/DM patients. Our results suggest that measurement of IL-1ra, together with clinical examination, may provide useful information for the followup of PM/DM patients.

Adult↗
PubMed1994

Four-week toxicity study of 4-methoxytoluene in rats.

4-Methoxytoluene was given by gavage to 4 groups of 20 rats at dosage levels of 0, 40, 120 or 240 mg kg-1 body weight/day for 4 weeks. There was a statistically significant decrease in serum creatinine and urea in the intermediate and high dose group for both sexes. Among males, a statistically significant decrease in the packed cell volume was observed in the high and intermediate dose group. A no-observed-effect level of 40 mg kg-1 body weight/day was determined.

Administration, Oral↗
PubMed1994

Influence of a dietary fiber on development of dimethylhydrazine-induced aberrant crypt foci and colon tumor incidence in Wistar rats.

Formation of aberrant crypt foci (ACF) in archived colon tissue from animals in a previous study was examined. The animals were fed a semisynthetic casein-based diet in which the carbohydrate pool was substituted with a dietary beet fiber (Fibeta) as the only source of fiber. Oral doses of dimethylhydrazine dihydrochloride (DMH-2HCl, 20 mg/kg body wt) once a week for 10 weeks were used as initiator. The rats were fed different levels of the fiber in a preinitiation period, during initiation, or in a postinitiation period. In general, the results showed a statistically significant inverse relation between duration of intake of high-fiber diet and number of animals with ACF, as well as the total number of ACF and number of small ACF (1-3 crypts) per affected animal. The previously reported data showed no protective effect of the dietary fiber at any stage of the colorectal carcinogenic process. The lack of correlation between the outcome of ACF and tumors could be related to the observation that statistically significant differences between groups were seen only in the total number of ACF and number of small ACF. The hypothesis that ACF are preneoplastic lesions needs to be supported by further experimental data. The present state of knowledge could indicate that ACF represent true preneoplastic lesions progressing into colon tumors or that ACF and colon tumors represent two parallel independent events as a consequence of the cancer initiation (i.e., the ACF not being preneoplastic lesions per se).

Animals↗
PubMed1994

Epitope mapping with synthetic peptides of 52-kD SSA/Ro protein reveals heterogeneous antibody profiles in human autoimmune sera.

The reactivity of autoantibodies present in the sera of 489 patients with Sjögren's syndrome (SS), systemic lupus erythematosus (SLE) and other autoimmune diseases was investigated by ELISA using recombinant 52-kD SSA/Ro protein (rRo52) and 39 overlapping synthetic peptides representing the entire sequence of Ro52. We report that IgG antibodies reacting with rRo52 were present in the sera of a large number of patients with SS (67% of patients with primary SS and 46% of patients with SS associated with SLE), whereas they were less frequent (10-25%) in SLE, rheumatoid arthritis (RA), juvenile chronic arthritis (JCA) and mixed connective tissue disease (MCTD), and absent in scleroderma. Among the 39 peptides tested, five were recognized by sera from 30-65% of patients with SS, namely peptides representing residues 2-11, 107-122, 107-126, 277-292 and 365-382. Patients with JCA had raised levels of IgG antibodies reacting with peptides 2-11 and 365-382, and 51% of patients with MCTD had raised levels of IgG antibodies reacting with peptide 365-382. None of the five peptides was recognized by more than 20% of sera from patients with SLE and RA. Interestingly, and of importance in the field of diagnostic tests based on peptides, the reactivity of antibodies to the Ro52 synthetic peptides varied greatly according to the origin of sera. Inhibition experiments using either patients' sera or antibodies induced in rabbits against Ro52 peptides showed that the four domains 2-11, 107-122, 277-292 and 365-382 are accessible on the surface of the Ro52 protein. These regions may thus be involved in the induction of specific antibodies in autoimmune patients.

Amino Acid Sequence↗
PubMed1994

Association of antimitochondrial antibodies type 5 and anti-beta 2 glycoprotein I antibodies in the antiphospholipid syndrome.

OBJECTIVE: To evaluate if antimitochondrial type 5 antibodies (AMA5) might be included among antiphospholipid syndrome (APS) markers. METHODS: In a retrospective study, blood variables of 48 patients with AMA5 were analyzed in relationship with clinical and biological markers of APS and systemic lupus erythematosus (SLE). RESULTS: We observed a high prevalence of false biological test for syphilis (95%), lupus anticoagulant (LAC) (71%), anticardiolipin antibodies (aCL) of IgG (71%) and IgM (75%) isotype, positive direct Coombs' test (54%), thrombocytopenia (52%), anti-B2 glycoprotein I antibodies (38%). Twenty-nine patients (61%) had at least one clinical manifestation of APS; 42% had recurrent arterial and/or venous deep thrombosis and 21% had recurrent fetal loss. But, for 2 patients, AMA5 were the sole detected immunological marker. Moreover, SLE was observed in 35% of the patients. These were different from 100 control patients with SLE with the respect to skin involvement and dsDNA antibodies which were less frequent (p < 0.01) and aCL, LAC, false biological test for syphilis (p < 0.001), positive direct Coombs' test and thrombocytopenia (p < 0.05) which were more frequent. CONCLUSION: Our data suggests (1) AMA5 is another marker of the APS (2) in patients with SLE, AMA5 seems to be a marker of a subset of SLE. This appears to justify the routine detection of these antibodies.

Adolescent↗
PubMed1994

[Conclusions of the first French workshop of standardization of anticardiolipin antibody determination associated with autoimmune pathology].

Anticardiolipine antibodies are a marker of the antiphospholipid syndrome. They are detected by Elisa. Despite its simplicity, the results obtained by this assay are not always reproducible despite several worldwide standardizations and the distribution of calibration sera by EN Harris. On 4 December 1992, the First French Anticardiolipin Antibodies Standardization Workshop was held in Paris. Eight coded standards were sent to 33 laboratories in France, one in Switzerland and one in Luxembourg. Some of them used several assays. Agreement between qualitative results was good for samples with high and moderate level of antibodies. But the results expressed in IgG antiphospholipid units were scattered, the interlaboratory coefficient of variation for each of the eight standards was higher than 70%, though the within-run coefficient of variation had a median value of 10%. Assays using bovine serum for the blocking buffer and for the dilution buffer seemed to give more reproducible results than assays using purified bovine serum albumin (p < 0.001). For only nine assays out of 38 which expressed results quantitatively, was a linear regression observed between the dilutions of a sample and the results expressed in IgG antiphospholipid units. Absence of linearity is an obstacle which must be overcome if we wish to compare quantitative results obtained by different laboratories.

Antibodies, Anticardiolipin↗
PubMed1994

[Treatment of acute systemic lupus erythematosus with intravenous infusions of cyclophosphamide. Value and limitations].

Monthly intravenous cyclophosphamide (IVCY) has been a recommended therapy for severe lupus nephritis or neurological flare-ups in lupus patients. But the optimal treatment regimen and duration remains unknown. We report our experience in an open study of 37 patients treated with monthly IVCY. Thirty-four women and 3 men, mean age 35.5 with a mean disease duration of 59 months, with a mean 5.7 ACR criteria for SLE were analysed. 27 (group I) had lupus nephritis (OMS Class III or IV) and 10 had neurological involvement (group II). In group I, after six months of IVCY, a significant improvement was noticed in the UCH-Middlesex clinical index (2.9 pts vs 7.8), the proteinuria (3.12 g/d vs 5.4), complement and split fractions (CH50 98.4 vs 48.9%; C3 877 vs 600 mg/l; C4 177 vs 128 mg/l), the level of anti-DNA antibodies (67.5 vs 775 UI/ml) and the daily dose of steroids (22 vs 44 mg/d). Kidney biopsies showed a reduction of the activity index despite a slight increase of the chronicity index (4.1 vs 6.3 pts and 5.5 vs 3.6 pts). Those results were not maintained at medium and long term. Moreover five patients presented with worsening of renal function during IVCY treatment and two patients relapsed after the end of the treatment. In group II significant improvement was noticed at six months concerning the clinical index (1.77 pts vs 7.17) and the daily dose of steroids, 3 patients died because of cerebral vasculitis refractory to IVCY. Adverse effects are frequent: infectious (25 among 20 patients), hemorrhagic cystitis (2 events in 1 patient), gastrointestinal side effects were common (12/37 patients). Were also noticed: neutropenia (5/37), transient amenorrhea (4/28), drug induced menopausis (2/28). Overall mortality is important (7/37), uneffectiveness of IVCY was noticed in 5 patients, flares occurred in 8 patient during or after stopping treatment. IVCY seems efficacious if given at the very beginning of the flare. Its usefulness is obvious at six months among clinical and biological data in patients with severe lupus nephritis or neurological flare. It seems that long term outcome on the renal function is not modified.

Acute Disease↗
PubMed1993

Carcinogenicity study of the emulsifier TOSOM and the release agent TOS in Wistar rats.

Groups of 60 Wistar rats of each sex were fed diets containing 3, 6 or 12% of the margarine emulsifier TOSOM (thermally oxidized soybean oil interacted with mono- and diglycerides of fatty acids) for 2.5 yr. In addition, three groups of 60 rats of each sex were fed two products of the release agent TOS (thermally oxidized soybean oil) in dietary levels of 1.2% TOS(G) (TOS from Grindsted Product A/S, Denmark) and 0.3 and 1.2% TOS(N) (TOS from Nexus Aps, Denmark), respectively for 2.5 yr. 120 rats of each sex fed a diet containing mono- and diglycerides served as controls. The diets given to all groups were isocaloric. Clinical appearance, food consumption, body weight and weight gain, survival, haematology, and clinical chemistry parameters were examined. Gross and histopathological examinations, including neoplastic and non-neoplastic lesions, were performed on all groups. Time to occurrence of tumours was recorded. No substance-related effect, including carcinogenicity, was found.

Animals↗
PubMed1993

Effects of high-fat diet on incidence of spontaneous tumors in Wistar rats.

In a 2.5-year carcinogenicity study, two groups, both including male and female Wistar rats, were fed two different diets with 4% and 16% fat. In addition to 4% soybean oil, the high-fat diet contained 12% mono- and diglycerides, of which 85% was stearic acid and 13% palmitic acid. There was no difference in food consumption, body weight, weight gain, and longevity between the two groups. A statistically significant increase in the incidence of tumors in the high-fat group was seen in fibroadenoma of the mammae (female, p = 0.05). No statistically significant difference was seen when the incidence of benign mammary tumors (adenomas and fibroadenomas) was combined, just as the overall incidence of mammary tumors (adenomas, fibroadenomas, and adenocarcinomas) was not significantly different between the groups. A statistically significant decrease in the incidence of tumors in the high-fat group was seen in adenoma of the parathyroid gland (male, p = 0.04) and medullary carcinoma of the adrenal gland (male, p = 0.04). Combining the incidence of benign and malignant tumors of the adrenal medulla led to a further increase in the level of significance (p = 0.02). The present study showed that a high-fat diet influenced the tumor incidence in certain organs of rats. However, the overall differences in tumor incidence between rats fed the low- and the high-fat diet are considered marginal. Therefore we were not able to confirm or deny the hypothesis that a high-fat diet promotes the development of cancer. It should be noted that, in our study, fat accounted for about 30% of the total energy in the high-fat diet. This is much below the amount of fat normally found in the western diet but corresponds well to the level recommended for human intake. In addition, the rats fed the high-fat diet did not gain more weight, even though no difference was recorded in food consumption (g/kg body wt) between the groups.

Adenofibroma↗
PubMed1993

Occurrence of antiperinuclear, antikeratin, and anti-RA 33 antibodies in juvenile chronic arthritis.

OBJECTIVES: Antiperinuclear factor (APF), antikeratin antibodies (AKA), and anti-RA 33 antibodies are currently considered to be good markers for the diagnosis of adult rheumatoid arthritis with or without rheumatoid factor (RF). The prevalence of these markers was retrospectively reviewed in children with juvenile chronic arthritis (JCA) to determine whether they were associated with specific features. METHODS: One hundred and twenty-four patients with JCA participated in this study. Controls included 28 patients with juvenile systemic lupus erythematosus and 21 healthy children. Antiperinuclear factor and AKA were determined by indirect immunofluorescence on buccal mucosal cells and oesophagus sections respectively. Anti-RA 33 antibodies were detected using a Western blot technique on HeLa cell nuclear extract. RESULTS: Antiperinuclear factor was virtually absent in all the tested subgroups and anti-RA 33 antibodies were detected only in a subset of patients with RF positive polyarticular onset. Antikeratin antibodies were found in 27% of all children with JCA and in 42% of those with RF negative polyarticular onset. These results were statistically significant compared with healthy controls, but the presence of AKA was not specific to any patient subgroup. Moreover, in contrast with previous studies in adult RA, no relation was found between the presence of AKA and disease severity or activity. CONCLUSION: These data suggest that APF, AKA, and anti-RA 33 antibodies are not useful for the diagnosis or classification of JCA.

Antibodies, Antinuclear↗
PubMed1993

Implications of animal welfare on toxicity testing.

The testing strategy for chemical substances is discussed with regard to obtaining improved quality of data for health assessment while respecting the ethical responsibility for consideration of the welfare of the animals involved. Ensuring animal welfare without indulging too much in anthropomorphism leads to better research/testing. Current trends in toxicity testing will result in tests involving more sophisticated techniques, better quality of laboratory animals, and eventually the use of fewer animals.

Animal Experimentation↗
PubMed1993

[Hypertrophic osteoarthropathy disclosing hepatic and pulmonary multifocal epithelioid hemangioendothelioma].

Epithelioid hemangioendothelioma is a rare, low-grade vascular malignancy reported for the first time in 1982 by Weiss and Enzinger. It involves one or, more rarely, several organs. We report a case involving the lungs and liver, in which the first manifestation was symptomatic hypertrophic osteoarthropathy. Findings four years after the diagnosis included very slow tumor spread, resolution of symptoms, and stabilization of radiological changes.

Adolescent↗