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Biomedical subjects

B W Fulpius

Publications and source records attributed to B W Fulpius.

35 records · Page 2Linked to original sources
PubMed1979

[Clinical and biological evolution of myasthenia gravis after thymectomy in a 13-year-old girl].

A 13-year-old girl suffering from rhumatoid arthritis developed a myasthenia gravis. Her circulating anti-acetylcholine receptor antibodies were observed before and after thymectomy. Surgical removal of the thymus was followed by complete clinical remission associated with a progressive decrease of the antibody level; these antibodies did not disappear completely even as late as 2 years after the operation.

Acetylcholine↗
PubMed1978

[Antibodies against nicotine-like acetylcholine receptors of central nervous system and muscles in epileptics with IgA deficiency].

Anti-muscle nicotinic acetylcholine receptor (nAR) antibodies were sought in epileptic patients without clinical signs of myasthenia gravis. Low titers of such antibodies were found in 3 cases characterized by primary generalized seizures, IgA deficiency and HLA A1 and B8 antigens. These three patients also had anti-brain nAR antibodies. In the serum of one patient with myasthenia gravis, anti-brain nAR antibodies were also detected. The titer was low despite a high titer of anti-muscle nAR antibodies. This may reflect the fact that the immune reaction in the three epileptic patients is primarily directed against the brain nAR.

Adolescent↗
PubMed1978

Interactions of acetylcholine receptor and acetylcholinesterase with lipid monolayers.

The interaction of acetylcholine receptor and acetylcholinesterase with lipid monolayers was followed by measuring changes in surface pressure. When injected into the subphase of a lipid monolayer, the proteins caused increases in surface pressure from 5 to 10 dynes/cm, indicating a penetration of protein into the monolayer. At pH values below the isoelectric point of the proteins the incorporation was improved. The same was observed when Ca2+ (2mM) was added. The presence of the enzyme in the mixed film could be demonstrated by using diiso [3H] propyl fluorophosphate-labelled acetylcholinesterase as well as by measuring enzyme activity. Acetylcholine receptor was shown to be present in the mixed film by using a complex made of the receptor and alpha-[3H]neurotoxin.

Acetylcholine↗
PubMed1978

Intrathymic pathogenesis of myasthenia gravis: transient expression of acetylcholine receptors on thymus-derived myogenic cells.

Differentiation of myogenic stem cells from undifferentiated thymic stem cells is thought to play a critical role in the pathogenesis of myasthenia gravis. The expression of membrane acetylcholine receptor (AChR) on the membranes of developing muscle clones in cultures of murine thymus reticulum was followed and found to be transient. AChR are first expressed shortly after fusion of myotubes. In subsequent stages of myogenic development, the density of homogenously distributed AChR is strongly increased, and, in addition, concentrated "hot spot" AChR areas appear. During further maturation, membrane AChR are lost. Highly mature myotubes (3 months in culture) lack substantial amounts of homogenous AChR, as well as hot spots.

Acetylcholine↗
PubMed1978

Immunological studies in thymectomized and non-thymectomized patients with myasthenia gravis.

Eleven thymectomized and ten non-thymectomized patients with myasthenia gravis, matched with respect to sex, age, duration and severity of the disease were investigated with respect to routine clinical features, electrophysiological examination, HLA-typing, auto-antibodies, lymphocyte subpopulations in peripheral blood, Concanavalin A-induced release of leucocyte migration inhibitory factor (LIF), in vitro lymphocyte activation by mitogens and antigens and response to primary immunization with dinitrochlorobenzene measured in vivo and in vitro. The following conclusions could be drawn. The immune response to external antigens seems to be normal in myasthenia gravis and thymectomy is not followed by general defects in immune competence; at least as investigated by current techniques. The only reduction of responsiveness demonstrable in the thymectomized group was a decreased release of LIF by Concanavalin A-stimulated lymphocytes. Primary immune responses appear to be increased after adult thymectomy, which may be due to a decrease in suppressor T-lymphocyte activity. A hypothesis is formulated that Concanavalin A-induced release of LIF may reflect the competence of suppressor T-lymphocytes in man.

Adolescent↗
PubMed1978

The pathogenesis of myasthenia gravis.

The identification and purification of the acetylcholine receptor molecule has permitted a major advance in understanding the pathogenesis of Myasthenia gravis. The author explains the central role of the receptor and its connections with the main features of the disease. He gives a description of the pathogenic mechanisms involved.

Acetylcholine↗
PubMed1977

Study of two different subpopulations of anti-acetylcholine receptor antibodies in a rabbit with experimental auto-immune myasthenia gravis.

Two different subpopulations of anti-acetylcholine receptor antibodies were studied during the evolution of experimental autoimmune myasthenia in one rabbit immunized with Torpedo acetylcholine receptor. The results show that the subpopulation of antibodies directed against the toxin-binding site of the receptor might play a role in the appearance of the paralysis observed in this particular case.

Acetylcholine↗
PubMed1977

A radioimmunoassay for the quantitative evaluation of anti-human acetylcholine receptor antibodies in myasthenia gravis.

A radioimmunoassay was developed for the quantitative evaluation of antibodies to the acetylcholine receptor in the serum of myasthenic patients. AcChR was extracted from human muscle. A detailed preparation of the 125I-labelled alpha-Bgt-AcChR complex used as antigen is reported. Usually, an average of 20 pmol were obtained form 100 g muscle. This preparation is stable for 1 month in presence of an inhibitor of proteolysis and sufficient for performing about fifteen assays. The labelled complex was incubated with increasing amounts of sera and precipitated with anti-human IgG serum. Titres were expressed in pmol 125I-labelled alpha-Bgt-AcChR complex precipitated per ml serum. Out of thirty-nine sera tested thirty-six had positive titres ranging from 0-1-46 pmol/ml. No anti-AcChR were detected in the sera from twenty-seven patients used as controls.

Antibodies↗
PubMed1976

Experimental myasthenia in Balb/c mice immunized with rat acetylcholine receptor from rat denervated muscle.

A new model of an autoimmune disease of the neuromuscular junction was obtained by injection of acetylcholine receptor purified from rat denervated muscles into Balb/c mice. Anti-rat, then anti-mouse acetylcholine receptor antibodies, appear in mouse serum during the immunization procedure. Electrophysiological investigations performed on immunized mice reveal a neuromuscular block similar to that found in myasthenia gravis. Not a single mouse with objective signs of muscular weakness was lacking anti-mouse acetylcholine receptor antibodies but no correlation was found between their level and the severity of the disease.

Action Potentials↗
PubMed1976

Accessibility to antibodies of acetylcholine receptors in the neuromuscular junction.

Antibodies to the acetylcholine receptor are present in the serum of myasthenic patients but one does not know if, in vivo and in situ, they can penetrate the intact neuromuscular junction and block directly the receptor. The present experiments demonstrate that molecules the size of antibodies can reach acetylcholine receptor in situ. The mouse diaphragm with its intact neuromuscular junction was used as a source of acetylcholine receptor. The receptor was revealed either directly by iodinated alpha-bungarotoxin covalently coupled to IgG or indirectly, once labelled with cobra toxin, by iodinated anti-cobra toxin antibodies.

Animals↗