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Biomedical subjects

C Specker

Publications and source records attributed to C Specker.

At least 37 records · Page 2Linked to original sources
PubMed1997

Cerebral microemboli in patients with antiphospholipid syndrome.

CNS involvement is one of the hallmarks underlying poor prognosis in SLE and for therapeutic strategies it is difficult to assess which patients are at risk. As detectability of cerebral microembolic signals (MES) using long-term transcranial Doppler ultrasonography (TCD) proved to be predictive of past and future thromboembolic events in patients with carotid artery stenosis, we investigated whether MES might be similarly useful in patients with antiphospholipid syndrome (APS). Our study population consisted of 46 SLE patients and five with primary APS (pAPS). Twelve of the 46 patients with SLE, 10 of them with secondary APS (sAPS), and four of five patients with pAPS had a history of cerebrovascular ischaemia (CVI). MES in the middle cerebral artery were detected in 14 of 16 patients with and in one of 35 without CVI (P < 0.001). Antiphospholipid antibodies (aPL) were positive in 12 of 15 patients with and 18 of 36 without MES, and the rate of MES correlated to the titre of aPL. MES from APS patients resembled in their energy distribution those from patients with symptomatic carotid disease and were significantly different from those associated with artificial heart valves. In conclusion, cerebral MES are detectable in APS patients and correlate with a history of CVI. Whether this innovative method may provide individual risk assessment in APS patients has to be addressed in prospective studies.

Adolescent↗
PubMed1996

Hyperprolactinemia in systemic lupus erythematosus?

The objective of this project was to determine the prevalence of hyperprolactinemia (HPRL) in systemic lupus erythematosus (SLE) and to evaluate the role of prolactin (PRL) as a disease-activity marker. We determined PRL in a cohort of 182 patients with SLE. Basal prolactin levels and clinical data (disease-activity index, sero-activity, medications) were analyzed in all patients. The findings show only mildly elevated PRL levels in four SLE-patients and normaprolactinemia in 98% (n = 178), without any association with disease activity. Our results differ from previous studies. HPRL appears not to be prevalent in SLE, nor to be associated with disease activity.

Adolescent↗
PubMed1995

Cerebral microembolism in patients with Sneddon's syndrome.

BACKGROUND: The pathogenesis of Sneddon's syndrome is unclear. This study addresses the question whether cerebral thromboembolism may be involved in the pathogenesis of the neurologic complications of the disorder. The study consisted of 13 patients with Sneddon's syndrome defined by both generalized livedo reticularis and a history of one or more cerebrovascular ischemic events; none had clinical or Doppler ultrasonographic evidence of atherosclerosis. METHODS: Transcranial Doppler microembolic monitoring of the middle cerebral artery; blood screening for antiphospholipid antibodies (lupus anticoagulant, anticardiolipin antibodies). RESULTS: Five patients (38%) showed clinically silent microembolism at transcranial Doppler monitoring, with individual microembolic event rates of the middle cerebral artery between 2 per hour and 33 per hour. In this group, the time since the last ischemic symptom was significantly shorter than in the eight patients without microemboli. Antiphospholipid antibodies were detected in three patients (23%), all of whom belonged to the microemboli-positive group. CONCLUSIONS: These data suggest that the detectability of both clinically silent cerebral microembolism and antiphospholipid antibodies may provide paraclinical evidence of active disease in patients with Sneddon's syndrome. The results support the notion that an immune-mediated prothrombotic state facilitating the formation of arterial thrombi with subsequent cerebral embolization, and/or triggering in situ thrombosis of cerebral vessels, plays a pathogenetic role in the neurologic manifestations of this disorder.

Adult↗
PubMed1995

Novel 68 kDa autoantigen detected by rheumatoid arthritis specific antibodies.

OBJECTIVE: To improve the understanding of the pathogenesis of rheumatoid arthritis (RA) by identifying novel, disease specific autoantibodies. METHODS: Total protein preparations from synovial membranes were separated electrophoretically and immunoblotted. Sera from RA patients were screened for predominant immunoreactions by blotting. A 68 kDa antigen target of the most predominant reaction was detected and further characterised. RESULTS: The dominant immunoreaction in most of the RA sera tested was with a 68 kDa antigen. The antigen is probably ubiquitously expressed. It has an isoelectric point of 5.1, is O-glycosylated, and is located in the endoplasmic reticulum, the cytoplasm, or both. Antibodies to the 68 kDa autoantigen were present in 64% of 167 RA patients tested, and could also be detected in seronegative RA patients, but were present in only 1% of 98 patients with other rheumatic diseases. They could not be detected in 55 healthy controls. CONCLUSIONS: Because of its high sensitivity (64%) and specificity (99%), the anti-68 kDa autoantibody not only provides another valuable parameter for diagnosis, but also represents an antibody that may be involved in the pathological mechanisms leading to RA. This hypothesis can be tested by investigating if 68 kDa specific T cells are present in RA patients.

Animals↗
PubMed1994

Effects of glucocorticoids in rheumatoid arthritis. Diminished glucocorticoid receptors do not result in glucocorticoid resistance.

OBJECTIVE: Lymphocytes of patients with rheumatoid arthritis (RA) have diminished receptor density; thus, patients with RA should show partial resistance to glucocorticoids. We investigated the glucocorticoid sensitivity of lymphocytes in RA patients compared with healthy subjects. METHODS: We determined the effects of glucocorticoids on lymphocyte proliferation and cytokine release. RESULTS: Proliferation and cytokine release were inhibited in RA patients to the same extent as in healthy controls. CONCLUSION: Diminished receptor density in RA patients does not result in glucocorticoid resistance.

Adult↗
PubMed1992

Glucocorticoid receptors in rheumatoid arthritis.

OBJECTIVE: Increasing evidence suggests that there is a close interrelationship between the immune system and the hypothalamic-pituitary-adrenal axis. One way these systems are linked is through specific receptor proteins for glucocorticoid hormones in lymphocytes. We sought to determine whether the levels of these receptors differ in patients with rheumatoid arthritis (RA), compared with levels in healthy subjects. METHODS: We determined the density and affinity of lymphocyte glucocorticoid receptors, as well as basal cortisol levels, in 90 patients with active RA and in 200 healthy controls, using a whole cell binding assay. RESULTS: The number of glucocorticoid receptors in RA patients was significantly lower than in controls (mean +/- SD 2,144 +/- 500 per cell versus 5,619 +/- 1,373 per cell; P less than 0.001), whereas there were no differences in binding affinity or cortisol levels. Glucocorticoid receptor density did not correlate with inflammatory disease activity. CONCLUSION: Since glucocorticoids are potent immunosuppressive agents, the decrease in their receptors suggests an impairment of the immune-hypothalamic-pituitary-adrenal axis in patients with RA.

Adult↗
PubMed1992

[Prevalence of lupus anticoagulant, autoimmune hemolysis, thrombocytopenia and disorders of platelet function in unselected patients with SLE].

Prevalence of lupus anticoagulant (LA) in patients with systemic lupus erythematosus (SLE) and clinical manifestations vary widely between different clinical series. We investigated the relation between LA, autoimmune hemolytic anemia (AIHA), thrombocytopenia and platelet dysfunction in 80 unselected patients with SLE. AIHA was found in 6 patients (7.5%) and thrombocytopenia in 10 patients (12.5%), which was not related to platelet aggregation abnormalities. Compared to controls, patients with SLE showed significantly prolonged aPTT and kaolin clotting time (KCT), but platelet aggregation induced by both collagen and thrombin was not impaired. LA activity as defined by Rosner et al. (index for LA/ICA) was found in 15 patients (18.9%). Only 7 of these patients showed a positive platelet neutralization test (Triplett) and 9a positive tissue thromboplastin inhibition test (Schleider). In our SLE patients 23.7% have suffered from at least one thrombotic complication. In patients with LA activity thromboembolic complications were increased (p < 0.05). Thrombocytopenia was found in 6% of LA-negative but in 20% of LA-positive patients.

Abortion, Spontaneous↗
PubMed1991

Immunoglobulin allotypes are not associated with HLA-antigens, autoantibodies and clinical symptoms in systemic lupus erythematosus. Members of the SLE Study Group.

Immunoglobulin heavy chain (G1m, G2m, G3m, A2m) and kappa light chain (Km) allotype and phenotype frequencies of 323 central European Caucasian patients with systemic lupus erythematosus (SLE) were examined and correlated with various genetic, serologic and clinical markers of SLE. No significant associations were found between immunoglobulin allotypes or phenotypes and all 20 parameters tested (nephritis, vasculitis, arthralgias, photosensitivity, discoid lesions, central nervous system disease, Raynaud's phenomenon, sex, anti-Ro, anti-La, anti-nRNP, HLA-DR1-DR7, HLA phenotypes B8-DR3, B7-DR2). It could therefore be assumed that Gm, A2m and Km allotypes were not associated with HLA-antigens and had no influence on the serologic and clinical expression of SLE.

Autoantibodies↗
PubMed1991

Hetero- and homozygosity of MHC class II gene products in systemic lupus erythematosus. The Members of the Deutsche Multizentrische SLE-Studie.

An analysis of HLA class II antigens in 356 white patients with systemic lupus erythematosus (SLE) showed that all HLA-DR and -DQ homozygous and heterozygous combinations appear with frequencies expected from the observed gene frequencies. HLA-DR2 and HLA-DR3 gene frequencies were both increased in SLE, as were the odds ratios of all DR2 and DR3 hetero- and homozygous combinations. HLA-DR2/C4AQ0 heterozygotes were also not increased over expected values. Therefore, gene complementation at MHC loci does not contribute to susceptibility to SLE, but rather one or two MHC allele(s) in linkage with HLA-DR2 and HLA-DR3.

Alleles↗
PubMed1991

Ankylosing spondylitis: an autoimmune disease?

Identification of several autoantibodies in serum samples from patients with ankylosing spondylitis or suspected ankylosing spondylitis is reported. Five antibodies associated with ankylosing spondylitis were identified by applying cytoimmunofluorescence and immunoblotting techniques to antigen pools from insect tissue. At least one of these antibodies was found in 82% of serum samples from patients with ankylosing spondylitis. A 36 kD drosophila antigen, which showed the most common and most dominant reaction, was further purified and isolated. Thirty two (34%) of the serum samples from 95 patients with definite ankylosing spondylitis and 12 (28%) of the serum samples from 43 patients with suspected ankylosing spondylitis reacted with this antigen. Antibodies purified from the 36 kD antigen reacted specifically with a 69 kD antigen present in separations of total protein preparations from human lymphocytes and HeLa cells. The 36 kD antibody was not found in 29 patients with rheumatoid arthritis nor in 38 apparently healthy controls. The prevalence of the 36 kD antibody was comparable in HLA-B27 positive and negative patients. In addition, the same immunoreaction was found in patients with so called 'seronegative' spondylarthropathies, particularly of the ankylosing spondylitis-type, suggesting that this antibody is specific for ankylosing spondylitis or other 'seronegative' spondylarthropathies with the typical clinical and radiological changes of ankylosing spondylitis.

Antibody Specificity↗
PubMed1991

Immunoglobulin allotypes in systemic lupus erythematosus--results of a central European multicenter study. SLE Study Group.

Immunoglobulin heavy chains (G1m, G2m, G3m, A2m) and kappa light chain (Km) allotype and phenotype frequencies were examined in 323 central European Caucasian patients with systemic lupus erythematosus (SLE). No significant differences were found between the different allotype or phenotype frequencies of the SLE patients and a control group of healthy individuals. Our results indicate that Gm, A2m and Km allotypes do not represent susceptibility factors for SLE in Caucasians.

Gene Frequency↗
PubMed1988

HLA antigens in ankylosing spondylitis associated with Crohn's disease. Increased frequency of the HLA phenotype B27,B44.

In a consecutive case study 231 patients with Crohn's disease were investigated for ankylosing spondylitis (AS) and HLA-A, B, C, DR antigen association. Eighteen patients (7.8%) had definite AS according to the New York criteria; 13 (72%) were HLA-B27 positive. The phenotype B27,B44 was seen in 8 patients (44%) compared to only 3 (1%) of 300 controls (p less than 10(-7), and 1 (0.5%) of 213 patients with Crohn's disease without AS (p less than 10(-7). We conclude that patients with the phenotype B27,B44 are highly at risk (relative risk = 68.8) for the common manifestation of Crohn's disease and AS.

Adult↗
PubMed1987

[Significant association of HLA-B8 with systemic lupus erythematosus and with specific serological markers].

Analysis of the HLA antigens of the A, B and C locus of 87 patients with systemic lupus erythematosus (SLE) revealed a significant elevation for HLA-B8 of 64% as compared to 22% in a healthy control group (n = 1850) (P less than 0.000001). Owing to the known linkage disequilibrium of this genetic marker with the HLA-A1 antigen, the HLA phenotype A1, B8 was found in 55% of the SLE patients (P less than 0.000001). Moreover, a significant association of the HLA-B8 in 82% (P less than 0.025) of Ro antibody-positive SLE patients (n = 22) and in 84% (P less than 0.025) of Ha antibody-positive patients (n = 19) was striking. A more frequent occurrence of this HLA antigen could also be detected in patients with a persistent nDNA antibody elevation and in patients with manifestation of the disease before the 40th year of life as compared to patients who manifested it later. An association of the HLA-B8 antigen with a raised disease activity of SLE can be inferred.

Adult↗
PubMed1985

[Ormond's disease and chronic venous obstruction].

Excretory urography has been one of the most helpful tools in diagnosis of retroperitoneal fibrosis (RPF). Ventro-medial deviation of the ureters at the level of lower lumbar spine with urinary obstruction and pointed clinical stenosis of the upper part of the ureters have been considered diagnostic of RPF. It can be easily forgotten that RPF can become clinically apparent as vascular disease. Various types of RPF appearances will be discussed in the light of two examples.

Female↗
PubMedDate not supplied

[RA-specific autoantibodies against a 68k antigen].

Despite commonly applied clinical criteria, the early diagnosis of rheumatoid arthritis (RA) often remains difficult, thus delaying on suitable early treatment. In search for a test furthering the early and reliable diagnosis of RA, we have screened for novel disease specific autoantibodies. To this end proteins were isolated from synovial membranes and other tissues following a special protein purification protocol, and these were separated electrophoretically. Western blots were then used to screen sera of RA patients and of individuals suffering from other rheumatic diseases for antibodies to any of these proteins. The most prominent RA specific immunoreaction was with a 68k antigen, occurring in 110 of 167 RA patients (sensitivity is 66%). The antibody could also be identified in seronegative RA patients but not in healthy individuals (55 tested), in only 1 SLE patient of a group of 98 patients with other rheumatic diseases and in 1 out of 22 HIV patients, resulting in a specificity of 99%. Moreover, the anti-68k antibody could be correlated with a more severe course of RA. 13 out of 20 anti-68k positive RA patients (58%) had subcutaneous nodules, while only 2 out of 11 anti-68k negative (20%) did. The mean sedimentation rate of these antibody positive patients was 51 mm/h and 26 mm/h for the negative respectively. The 68k antigen was shown to be present in all human tissues investigated and is probably ubiquitously expressed. It is either located in the endoplasmatic reticulum or cytoplasm or both. Its isoelectric point is 5.1. It proved to be O-glycosylated and contains only one or a few sugar residues as the untreated and the deglycosylated antigen identical electrophoretical mobilities. The patient derived anti-68k antibodies were directed against the sugar residue: deglycosylation of the antigen completely abolished its immunoreactivity. N-acetylglucosamine competes with the antibody for binding the 68k antigen. The antigen physicochemical data of the 68k antigen argue against identity with one of the autoantigens in this molecular mass range already known to be associated with RA or other autoimmune diseases. It is neither identical to the 62k human antigen (EBNA-1) nor to RA33 (A2hnRNP), the 50k Sa antigen or the Hsp70 class of heats-hock proteins. It is argued that the particular method of protein purification applied in combination with separation via SDS-PAGE in the presence of urea, made it possible to detect a hitherto unidentified antigen. Considering the striking disease specificity of the anti-68k antibody it is now worthwhile to look for corresponding autoreactive T cells in order to analyse its role in the pathogenesis of RA.

Arthritis, Psoriatic↗