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Biomedical subjects

B Lang

Publications and source records attributed to B Lang.

At least 19 recordsLinked to original sources
PubMed1992

The synaptic vesicle protein synaptotagmin associates with calcium channels and is a putative Lambert-Eaton myasthenic syndrome antigen.

Immunoglobulin G fractions from patients with Lambert-Eaton myasthenic syndrome (LEMS), an autoimmune disease of neuromuscular transmission, immunoprecipitate 125I-labeled omega-conotoxin GVIA-labeled calcium channels solubilized from rat brain. A 58-kDa antigen was detected by probing Western blots of partially purified calcium channels with LEMS plasma and IgG and was shown to be the relevant antigen in omega-conotoxin receptor immunoprecipitation. Monoclonal antibody 1D12, produced by immunizing mice with synaptic membranes, has properties similar to these autoimmune IgGs in both immunoprecipitation and Western blotting assays. 1D12 antigen was purified by immunoaffinity chromatography and shown to bind LEMS IgG. The antigen was identified by screening a rat brain cDNA library with 1D12 and was found to have strong homology to the synaptic vesicle membrane protein synaptotagmin. Our results indicate therefore that these antibodies immunoprecipitate omega-conotoxin receptors by binding to synaptotagmin that is associated with calcium channels. We suggest that the interaction between synaptotagmin and the voltage-gated calcium channel plays a role in docking synaptic vesicles at the plasma membrane prior to rapid neurotransmitter release and that autoantibody binding to a synaptotagmin-calcium-channel complex may be involved in the etiology of LEMS.

Antibodies, Monoclonal↗
PubMed1992

The genetic basis of Ro and La antibody formation in systemic lupus erythematosus. Results of a multicenter study. The SLE Study Group.

Antibodies against Ro and La, including recombinant La and recombinant 60 kD-Ro, were determined by counter immunoelectrophoresis and ELISA in over 300 central European systemic lupus erythematosus (SLE) patients. The presence of both Ro and La antibodies was strongly associated with the MHC haplotype B8-C4AQ0-DR3-DQ2, the association being strongest for DR3. After exclusion of all B8-DR3 positive patients only DR3 positive patients still showed an increased incidence of Ro and La antibodies, suggesting DR3 as the primary association factor. High titers of La antibody, but not of 60 kD-Ro antibody, were also significantly associated with the presence of DR3. Other DR and DQ antigens or heterozygous DQ combinations were not significantly associated with Ro and La antibodies.

Antibodies, Antinuclear↗
PubMed1992

Paraneoplastic cerebellar degeneration. III. Cerebellar degeneration, cancer, and the Lambert-Eaton myasthenic syndrome.

We studied nine patients with a subacute onset of a pancerebellar syndrome. Six had known cancer (three small-cell carcinoma of the lung [SCLC], one metastatic small-cell carcinoma, one small-cell carcinoma of the prostate, and one non-Hodgkin's lymphoma). Six of eight who had neurophysiologic testing, including the three patients without detectable cancer, had coexistent Lambert-Eaton myasthenic syndrome (LEMS). In two of the patients, LEMS was discovered only by neurophysiologic testing. We looked for anti-Purkinje cell autoantibodies in all patient's sera and in four patients' CSF. We also looked for autoantibodies to voltage-gated calcium channels (VGCCs) in seven patients' sera and two patients' CSF, using the 125I-omega-conotoxin radioimmunoassay. We were unable to detect anti-Purkinje cell autoantibodies in any patients' serum or CSF. However, there were raised titers of anti-VGCC autoantibodies in five of seven patients' serum, including one patient with SCLC who did not have LEMS, and in the CSF of one of two patients. We conclude that the frequency of presentation of a pancerebellar syndrome with LEMS is higher than expected by chance and is usually associated with cancer. In some of these patients, LEMS may be clinically occult. The presence of LEMS and raised titers of anti-VGCC autoantibodies in some patients with subacute cerebellar degeneration is suggestive of an autoimmune etiology even though anti-Purkinje cell antibodies could not be detected. Anti-VGCC autoantibodies are not confined to LEMS. They may be found at high titer in CSF as well as serum.

Aged↗
PubMed1992

MHC gene products and anticardiolipin antibodies in systemic lupus erythematosus results of a multicenter study. SLE Study Group.

Anticardiolipin antibodies (aCL) and HLA-DR antigens were determined in 314 central European patients with systemic lupus erythematosus (SLE). Both HLA-DR4 and DR7 were increased in aCL-positive patients, and aCL were significantly associated with DRw53. The association between DRw53 and aCL was also apparent in those 17 patients with SLE and the anticardiolipin syndrome. There was no association between aCL and HLA-DQ or C4 alleles in SLE.

Antibodies, Anticardiolipin↗
PubMed1992

Search for cross-reactive idiotypes on monoclonal and myasthenia gravis acetylcholine receptor antibodies.

Myasthenia gravis patients have serum anti-acetylcholine receptor antibodies that compete with monoclonal antibodies for binding to epitopes on the human acetylcholine receptor. To investigate the presence of shared idiotypes we immunised syngeneic mice with each of ten well-characterised monoclonal antibodies, previously raised against purified human acetylcholine receptor, and tested the polyclonal antisera and seven monoclonal anti-idiotype antibodies, for binding to the antigen-combining site, to framework idiotopes, and by ELISA. The polyclonal sera were mostly directed against antigen-combining site idiotopes and cross-reacted only with monoclonal anti-acetylcholine receptor antibodies that bound to the same region on the acetylcholine receptor. In contrast, five of the seven IgM monoclonal anti-idiotypic antibodies raised, none of which demonstrated antigen-combining site specificity in solution, cross-reacted with mAbs binding to more than one region. None of the antisera showing reactivity with the antigen-combining site inhibited the binding of MG anti-acetylcholine receptor antibody.

Animals↗
PubMed1992

[Systematic lupus erythematosus and pregnancy].

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects primarily women of childbearing age. 20-30 years ago it was common belief that SLE is exacerbated during pregnancy. Recent studies, however, could not support this notion. The likelihood of an increase in clinical activity of SLE is similar during pregnancy and in nonpregnant patients. It correlates directly with the activity of disease at the time of conception. The pregnancy outcome in patients with SLE has improved considerably in recent years. The frequency of fetal loss, however, still remains higher in SLE patients than in healthy women. In most of the cases fetal loss is due to habitual abortions, intrauterine death and premature labors. The main reasons are anti-phospholipid antibodies and the activity of SLE at the onset of pregnancy, respectively during the pregnancy. For monitoring disease activity and especially for distinguishing between the development of eclampsia and exacerbation of SLE, periodic determinations of complement proteins CH50, C3, C4 and C3d are helpful. A prophylactic therapy e.g. with prednisone in pregnant SLE patients is not justified. However, when SLE is exacerbating immunosuppressive therapy with prednisone and, if needed in combination with azathioprine, should be administered. In cases with high antiphospholipid antibody titers and prior fetal loss a treatment with low-dose acetylsalicylic acid can be considered.

Female↗
PubMed1992

[Neonatal lupus erythematosus as an example of passively acquired autoimmunity].

Neonatal lupus erythematosus is a typical example of passively acquired autoimmune disease. Congenital heart block is the main complication caused by transplacentally transferred maternal IgG antibodies directed against SS-A- or SS-B-antigen. While the transient lupus dermatitis occurs post partum and is often triggered by UV-light exposition, the irreversible cardial damage takes place between the 18. and 24, week of pregnancy. During this period 52-kD-SS-A- and 48-kD-SS-B-antigen are expressed in the fetal cardial tissue. The autoimmune reaction leads to an irreversible fibrotic destruction of the atrioventricular node. The resulting AV block and an antibody-induced perimyocarditis support the development of fetal bradyarrhythmia and hydrops. The very early diagnosis of a fetal heart block in bradycardiac fetus by echocardiography is essential for a consecutive therapy with steroids. By a reduction of the maternal antibodies an improvement of cardial symptoms in the fetus may be achieved in cases with fetal hydrops. Pregnant women at high risk with known connective tissue disease, previous children with congenital heart block, high titers of SS-A-/SS-B-antibodies and immunogenetic predisposition (HLA-DR3) have to be monitored intensively because of the possibility of a prophylaxis with dexamethasone and, in some selected cases, plasmapheresis.

Female↗
PubMed1992

Cerebral aneurysm in relapsing polychondritis.

A 51-year-old woman with relapsing polychondritis involving auricular and nasal cartilage, hearing loss, vasculitic skin lesions and a cerebral aneurysm of the posterior cerebral artery is described. Cerebral aneurysm is a rare manifestation of relapsing polychondritis which to our knowledge has not yet been described.

Cerebral Angiography↗
PubMed1992

[Effects of surgical therapy of extreme obesity on physical and psychological outcome].

More than 400 patients with morbid obesity were treated surgically in our unit over the past 18 years. Three different methods (intestinal bypass, bilio-intestinal shunt and vertical banded gastroplasty) were used. In order to assess any postoperative increase in life quality and to compare the three different techniques, 25 matched patients from each group were followed up and the findings compared with a group of non-operated morbidly obese persons. Psychological tests were also supplied. Irrespective of the technique performed a significant increase in quality of life was obtained in 75% of the cases.

Activities of Daily Living↗
PubMed1991

Autoimmune aetiology for acquired neuromyotonia (Isaacs' syndrome)

Neuromyotonia is a rare disorder of unknown cause in which hyperexcitability of peripheral motor nerves leads to incapacitating muscle twitching, cramps, and weakness. We investigated an antibody-mediated mechanism for neuromyotonia in a 24-year-old man with a 7-year history of severe disease unresponsive to pharmacological treatment. Two periods of plasma exchange each produced almost complete disappearance of symptoms for 2-3 weeks, and a highly significant decrease in recorded neuromyotonic discharges. Injection of the patient's plasma or purified IgG into mice significantly enhanced in-vitro resistance to d-tubocurarine at the neuromuscular junction of phrenic nerve-diaphragm preparations. This finding suggests that an increase in neurotransmitter release might result from an antibody-mediated reduction in the number of functional potassium channels that normally regulate nerve excitability. The demonstration of pathogenic IgG autoantibodies in acquired neuromyotonia suggests that immunosuppressive treatment may be helpful in severe cases.

Adolescent↗
PubMed1991

Calcium channel autoantibodies in the Lambert-Eaton myasthenic syndrome.

We have tested 36 patients with the Lambert-Eaton myasthenic syndrome for serum antibodies to voltage-gated calcium channels by using an immunoprecipitation assay with [125I] omega-conotoxin-labeled voltage-gated calcium channels extracted from a human neuroblastoma cell line, SKN-SH. Forty-four percent of these patients had significant levels of antibody (30-1,466 pM) compared with healthy control individuals (less than 15 pM). The incidence of positive sera in patients without associated small cell lung carcinoma (61%) was greater than in those patients with small cell lung carcinoma (28%). Results correlated strongly with results obtained using voltage-gated calcium channels extracted from the small cell lung carcinoma line, MAR5. Anti-voltage-gated calcium channel antibody titers did not correlate with disease severity across individuals, but longitudinal studies in 2 patients receiving immunosuppressive therapy showed a clear inverse relation between antibody titer and an electromyographic index of disease severity. The incidence of positive sera among patients with other neurological disorders was not significant, but 8 of 12 patients with rheumatoid arthritis or systemic lupus erythematosus had raised titers (30-82 pM). We conclude that the antibodies detected in this assay are heterogeneous and that some of them are likely to be implicated in this disorder of neuromuscular transmission. The assay should prove useful as an additional diagnostic aid in patients with Lambert-Eaton myasthenic syndrome.

Action Potentials↗
PubMed1991

Seronegative myasthenia gravis: a plasma factor inhibiting agonist-induced acetylcholine receptor function copurifies with IgM.

Anti-acetylcholine receptor antibodies cannot be detected by standard radioimmunoassay in 10 to 15% of patients with generalized myasthenia gravis (seronegative myasthenia gravis). We investigated the effect of seronegative myasthenia gravis plasma on 22Na+ flux through acetylcholine receptors and voltage-gated sodium channels in the human rhabdomyosarcoma cell line, TE671. Fourteen of 19 seronegative MG plasmas inhibited acetylcholine receptor 22Na+ flux; none inhibited voltage-gated sodium channel flux. The inhibitory activity was found in the IgG-depleted fraction, and copurified with IgM after gel-filtration chromatography. Inhibitory activity was absent from the plasma of 8 healthy control subjects and of 6 patients with the Lambert-Eaton myasthenic syndrome, but was present in the IgG-depleted plasma fraction of 4 of 6 seropositive patients with myasthenia gravis and all 5 patients with demyelinating polyneuropathy. We conclude that a low-affinity serum factor, probably an IgM antibody, found in a high proportion in patients with seronegative and those with seropositive myasthenia gravis may contribute to the muscle weakness in myasthenia gravis, but its role in these and other neuroimmunological disorders requires further investigation.

Autoantibodies↗
PubMed1991

Automated amplification and sequencing of human mitochondrial DNA.

Part of the human mitochondrial D-loop region was amplified by two successive rounds of polymerase chain reaction (PCR) amplification. In the second PCR reaction, nested primers were used, of which one contained the M13-21 universal primer sequence. By using nonequal concentrations of primers in the second amplification, single-stranded DNA was generated. This was then sequenced directly by the diodeoxy chain termination method using dye-labelled universal sequencing primers in conjunction with a fluorescence-based DNA sequencer. This enabled a 403-base-pair hypervariable segment of the D-loop region to be readily sequenced in a single reaction. This paper describes a protocol which enables mitochondrial sequence information to be generated rapidly and automatically. It is likely to be of importance in forensic analysis where the DNA is too degraded or of insufficient quantity to be analysed by other techniques.

Amino Acid Sequence↗
PubMed1991

Primary antiphospholipid syndrome (PAPS). Two case reports and therapeutic implications.

Antiphospholipid antibodies (aPL) interfere with the coagulation system and can cause thrombosis and other clotting disorders. The combination of recurrent venous thrombosis, arterial embolism and recurrent fetal loss is nowadays considered to be primary antiphospholipid syndrome (PAPS), provided an underlying systemic lupus erythematosus (SLE) has been excluded and aPL have been detected. We report on two patients with PAPs, and show the course of their IgG- and IgM-anticardiolipin antibody (aCL) titers during immunosuppressive therapy with prednisone and azathioprine or cyclophosphamide. Over a period of 18 months this therapy was effective in preventing relapses of thrombo-embolism and other complications. Therapy with cyclophosphamide resulted in normalization of the aCL titers in one of the two reported cases. Azathioprine treatment reduced the aCL titer in the other patient, without fully normalizing it. Based on our observation, we propose to treat PAPS-associated severe and recurrent thrombo-embolic complications by aggressive immunosuppression, including azathioprine and cyclophosphamide.

Adolescent↗
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

[Chronic immunoproliferative syndromes].

Immunoproliferative syndromes are etiologically unclear, rare diseases which involve polyclonal B- and/or T-cell proliferations and frequently develop into malignant non-Hodgkin-lymphoma. Typically, these diseases are characterized by lymphadenopathies, hepatosplenomegaly, general fatigue and autoimmune phenomena. Here we briefly outline 6 syndromes, two of which--the "pluripotential chronic immunoproliferative syndrome" (CPIS) and the "angioimmunoblastic lymphadenopathy" (AILD)--are discussed in more detail. We favor the notion that CPIS is a variant form of AILD clinically dominated by severe autoimmune hemolytic anemia. Both diseases share the high frequency of anti-cytoskeleton autoantibodies.

Chronic Disease↗
PubMed1991

Low dose methotrexate therapy for rheumatoid arthritis complicated by pancytopenia and Pneumocystis carinii pneumonia.

In a patient with rheumatoid arthritis pancytopenia and Pneumocystis carinii pneumonia occurred during low dose methotrexate therapy. This case emphasizes the potential development of opportunistic infections even with low dose methotrexate. Pneumocystis carinii pneumonia resembles methotrexate induced pneumonitis. Therefore opportunistic infections should be considered before a definite diagnosis of methotrexate induced pneumonitis is made.

Adolescent↗