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M M Rapport

Publications and source records attributed to M M Rapport.

At least 37 records · Page 2Linked to original sources
PubMed1981

An immunological model of epilepsy: seizures induced by antibodies to GM1 ganglioside.

Following observations that the intracerebral injection into rats of antiserum to brain gangliosides resulted in recurrent epileptiform activity and that seizure activity was not seen if antibodies were removed by absorption of the antiserum with pure GM1 ganglioside, a study was undertaken to establish characteristics of the immunological agents used to produce this model of epilepsy. It was determined that the potencies (antibody titers with GM1 ganglioside) of antiganglioside sera can be correlated with the intensities of epileptiform activity they induce; that immunoglobulin fractions from antiganglioside sera are even more effective biologically than the antisera; and that antibodies to GM1 ganglioside purified by affinity chromatography can also induce recurrent epileptiform discharges but are not as effective as either native antiserum or immunoglobulin fractions.

Animals↗
PubMed1980

Synaptic membrane antigens: detection and characterization.

Analysis of the antigenic components of synaptic membranes presents several problems caused by detergents required to solubilize the proteins. These problems involve detection of the reaction between antibodies and proteins in the detergent extract as well as characterization of the individual antigens after further purification. We found a satisfactory solution for analysis of rat synaptic membranes by using rocket immunoelectrophoresis with an intermediate gel containing 0.5% berol to sequester sodium dodecyl sulfate (SDS) and an antibody gel containing 0.1% berol to maintain the solubility of the proteins. With antiserum prepared against a highly purified synaptic membrane fraction, these conditions gave rocket heights proportional to protein concentration (for the major rocket) and showed no reactions with membrane extracts of liver, kidney and spleen. By separation on gradient slab gels containing SDS, 4 antigenic polypeptides were found in Berol extracts of synaptic membrane, having apparent molecular sizes of 56,000, 58,000, 62,000 and 66,000 daltons. The SDS extract of the berol insoluble residue contained 3 antigenic polypeptides (12,500; 15,000, 16,500 daltons). The combined use of gradient slab gel electrophoresis in SDS and rocket immunoelectrophoresis with an intermediate gel to remove SDS provides a sensitive and rapid method for definitive identification of individual antigenic components in detergent extracts of membrane and for further purification of these antigens.

Animals↗
PubMed1979

Glial fibrillary acidic protein in ependymomas and other brain tumors. Distribution, diagnostic criteria, and relation to formation of processes.

Glial fibrillary acidic protein (GFAP) was studied in ependymomas by the three-step immunoperoxidase method and compared to results in astrocytomas and normal tissues. An order of reactivity for GFAP is presented. Diagnostic criteria, based on GFAP content, are proposed. In ependymomas GFAP-positive cells give rise to only some of the tumor cells, usually those forming tubules and perivascular arrangements. It is hypothesized that the same GFAP-positive cells may form tubules at their luminal poles and may produce perivascular arrangements at their other poles. The aberrant regulation associated with neoplastic transformation in glia is often, but not always, reflected in increased GFAP content. In both astrocytes and ependymal cells GFAP may have a similar function since in both cells the increase in GFAP appears to be related to the development of fibrillary processes.

Astrocytes↗
PubMed1978

Topographic studies of glycoproteins of intact synaptosomes from rat brain cortex.

Glycoproteins in the external surface of intact synaptosomes from rat brain cortex have been studied by oxidation of exposed galactose and galactosamine groups by galactose oxidase followed by reduction with labeled sodium borohydride. Purified synaptosomes were labeled, disrupted by osmotic shock, and the particulate components were fractionated on diatrizoate to give four synaptosomal membrane fractions (A to D) and a mitochondrial pellet (E). Fractions A and B represent highly purified synaptosomal plasma membranes. After separation of their polypeptides by electrophoresis, 4/5 of the label was present in two bands: one about 72 000 and the other between 7800 and 3200 daltons. Seven other bands were labeled to various degrees: 160 000, 96 000, 53 000, 39 000, 34 000, 23 000 and 16 000 daltons. With isolated membranes (which incorporate 5--6 times more label) 4/5 of label was present in polypeptides in three ranges: 160 000--96 000, 70 000--40 000 and 7800--3200. The number of polypeptides that can be labeled by treatment of isolated membranes is very large. In comparison, glycoproteins whose topographical distribution permits interaction with large molecules at the synpatic surface are very limited. It is further suggested that the external synaptosome membrane involves a relatively tight network of interacting molecules that cannot be readily penetrated by large molecules.

Animals↗