PubMed Health⌕ Search

Biomedical subjects

E Molnár

Publications and source records attributed to E Molnár.

98 records · Page 6Linked to original sources
PubMedDate not supplied

Electron microscopic study of infantile renal biopsy specimens.

Out of 54 open renal biopsies performed on children, 17 were selected and studied not only by light microscopy but also by electron microscopy. Statistical-mathematical analysis of basement membrane thickness-measurements was carried out. It is concluded that electron microscopic investigation of the renal biopsy material is required in selected cases involving diagnostic or therapeutic problems. In nephrotic syndrome it may help above all to separate minimal changes from early forms or glomerular lesion of the focal sclerosing type. Electron microscopy can also be useful in any of the mono- and oligosymptomatic renal diseases. In those cases only electron microscopy makes it possible to provide exact morphological diagnosis which is necessary to the proper therapy.

Child↗
PubMedDate not supplied

Assembly intracellular targeting and cell surface expression of the human N-methyl-D-aspartate receptor subunits NR1a and NR2A in transfected cells.

The intracellular trafficking, assembly, and cell surface targeting of the human N-methyl-D-aspartate receptor subunits NR1a and NR2A has been studied using both transiently and permanently transfected mammalian cell lines. The expression of either NR1a or NR2A alone does not result in significant cell surface expression of either subunit as determined by cell surface biotinylation and immunofluorescence staining. When NR1a is expressed alone large intracellular accumulations of the subunit are formed which do not co-localize with the golgi apparatus markers protein p58 and wheat germ agglutinin, but do co-localize with the endoplasmic reticulum marker calreticulin. Co-expression of NR1a and NR2A results in a reduction of these intracellular accumulations and the appearance of both subunits on the cell surface. Immunoprecipitation of NR1a from in vitro translated subunit proteins showed that NR2A could only be immunoprecipitated with NR1a when both subunits were co-synthesized in the presence of microsomes. When cells expressing NR1a and NR2A were incubated with [35S]methionine in the presence of Brefeldin-A, a drug which prevents protein transport from the endoplasmic reticulum, NR2A could be immunoprecipitated by an antiserum specific for NR1a. Together these results suggest that the NMDA receptor subunits are assembled in the endoplasmic reticulum and that co-synthesis of the subunits is necessary for their association and their successful cell surface targeting.

Animals↗
PubMedDate not supplied

Surface expression and metabolic half-life of AMPA receptors in cultured rat cerebellar granule cells.

The surface expression and metabolic turnover time of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors are important factors in determining the involvement of these proteins in synaptic function. We used the membrane-impermeant chemical crosslinking reagent BS3 and subsequent immunoblot analysis to show that a large proportion of each of the AMPA receptor subunits GluR1-4 is surface expressed in cultured rat cerebellar granule cells. The apparent molecular mass of the individual subunits was 105 kDa and the surface expressed crosslinked complex was 530 kDa for each of the antibodies tested. These results are consistent with functional ionotropic glutamate receptors being pentameric subunit assemblies. We investigated the time course of AMPA receptor surface expression using the membrane-impermeant biotinylating agent NHS-SS-biotin. The half-life of surface expressed AMPA receptors was found to be 30 h. To estimate the mean degradation rate of AMPA receptors and total trichloracetic acid (TCA)-precipitable protein we used [35S]methionine/cysteine pulse-chase labelling. The half-life of AMPA receptors immunoprecipitated with anti-GluR1 antibody was approximately 48 h and the half-life of total TCA-precipitable protein from the same samples was 37 h.

Animals↗