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Biomedical subjects

M E Seybold

Publications and source records attributed to M E Seybold.

At least 19 recordsLinked to original sources
PubMed1985

Cluster headache. Local anesthetic abortive agents.

Cocainization of the sphenopalatine fossa region has been shown to abort acute cluster headaches rapidly. Whether this response occurs by sympathomimetic action or via local anesthetic effect has been unknown. In this study, lidocaine hydrochloride was given as a therapeutic abortive agent to patients with cluster headache to elucidate cocaine's mechanism of action in relieving symptoms and to search for a safe, nonaddicting agent for self-administration. Using a 4% lidocaine solution applied to the sphenopalatine fossa, four of five patients obtained rapid relief of nitrate-induced cluster headaches and associated signs. Lidocaine was also effective in relieving spontaneous attacks. These results indicated that anesthetic rather than sympathomimetic effects are responsible for cocaine-medicated abortion of cluster headache, that transmission of pain in cluster headache likely occurs via the sphenopalatine fossa, and that topical lidocaine is effective in rapidly aborting acute cluster headache.

Adult↗
PubMed1982

Immunopathology of acetylcholine receptors in myasthenia gravis.

It is now clear that the muscular weakness and fatigability seen in MG result from an antibody-mediated immune response to AChR. The mechanisms by which antibodies impair transmission are moderately well understood and detection of antibodies in patient's sera is a reliable diagnostic test for the disease. The spectrum of antibody specificities produced in MG is also beginning to be understood, largely through the use of antibodies produced in the experimental model EAMG. Treatment for MG continues to rely heavily on the symptomatic relief afforded by acetylcholinesterase inhibitors. However, the recent recognition of the autoimmune nature of MG has led to increased emphasis on immunosuppression and antibody removal with some beneficial effects. Despite all that has been learned, the level of ignorance has just been pushed back one step--from the neuromuscular junction to the immune system. What initiates the immune response to AChR in MG and how to specifically suppress this aberrant response remain completely unknown.

Acetylcholinesterase↗
PubMed1982

Specificities of antibodies to acetylcholine receptors in sera from myasthenia gravis patients measured by monoclonal antibodies.

The pattern of antibody specificities in sera from patients with myasthenia gravis (MG) was determined by the ability of monoclonal antibodies against defined determinants on the acetylcholine receptor molecule to inhibit binding of the serum antibodies to receptor from human muscle. We found that MG patients produce fundamentally the same pattern of specificities as that produced by animals immunized with receptor purified from fish electric organs or mammalian muscle. Most of the antibodies are directed at the "main immunogenic region' which is located on the extracellular surface of the alpha subunit and is distinct from the acetylcholine binding site. Regions on the beta and gamma subunits near the main immunogenic region are also significantly immunogenic. In one patient the proportions of antibodies to various regions are constant over time despite changes in total antibody amount and clinical state. Between patients there is no obvious correlation between antibody specificities and clinical state. These data suggest that the autoimmune response in MG is stimulated by human receptor rather than a crossreacting (e.g., viral) antigen and that in both MG and experimental autoimmune MG the pattern of specificities produced is determined by the inherently immunogenic structural features of the receptor molecule. They also suggest that the wide differences in clinical state sometimes observed between patients with the same total concentration of antireceptor antibody are due primarily to differences in endogenous factors which affect the safety factor for neuromuscular transmission rather than to the presence of especially pathogenic antireceptor specificities.

Antibodies, Monoclonal↗
PubMed1981

Patterns of acetylcholine receptor antibody fluctuation in myasthenia gravis.

Serial acetylcholine receptor antibody (AChR-ab) titers have been followed in 32 patients with myasthenia gravis (MG) for an average of 43 months (range 12-81 months). Seventeen patients became asymptomatic or markedly improved during the study, 12 of whom showed AChR-ab decreases of greater than 50% sustained for 12 months. Only three of 15 patients showing no substantial clinical improvement had AChR-ab decreases greater than 50%. Steroids were more often associated with AChR-ab suppression than was thymectomy. The differences in AChR-ab suppressibility among identically treated patients were not predictable by any clinical characteristics studied. The study indicates a strong relationship between clinical course and AChR-ab in the individual patient when sustained improvement over 12 months and AChR-ab decreases greater than 50% are examined.

Adolescent↗
PubMed1981

Myasthenia gravis in infancy.

Symptoms of myasthenia gravis in infancy may occur from passive transfer of maternal disease, acquired autoimmune disease, or nonautoimmune hereditary disease. Of nine patients with infantile-onset myasthenia who were not born to mothers with the disease, two had detectable antibody to acetylcholine receptor. Patients with or without antibodies were clinically indistinguishable, except for the occurrence of similar disease in siblings of patients without antibody. Differentiation of autoimmune and hereditary, myasthenia in infancy is necessary for appropriate therapeutic measures and genetic counseling. Antibody determinations provide a useful aid in this differentiation.

Antibodies↗
PubMed1981

Antiacetylcholine receptor antibody and its relationship to HLA type in asymptomatic siblings of a patient with myasthenia gravis.

Antibodies to acetylcholine receptors (AChR-ab) were detected in a patient with myasthenia gravis (MG) and at much lower levels in her asymptomatic fraternal twin and one other asymptomatic sibling. These three carried the HLA-B8 allele, as did four other family members. In a previous study, we observed no AChR-ab in 175 non-MG patients. The occurrence of AChR-ab in 3 of 12 siblings suggests that all were affected by an unidentified pathologic factor acting on a favorable genetic background.

Autoantibodies↗
PubMed1980

The superficial radial nerve: techniques for evaluation.

Several methods for obtaining radial nerve sensory responses have been compared. A technique for antidromic latency measurement over a fixed distance most consistently produced responses which were easy to obtain, reliable and well tolerated by the subjects.

Adult↗