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61.
Hypoxia Dramatically Increases the Nonspecific Transport of Blood-Borne Proteins to the Brain 总被引:5,自引:1,他引:4
Abstract: Increased cerebrovascular permeability is an important factor for the development of cerebral edema. To investigate the effect of hypoxia on the transport of blood-borne proteins to the brain, we used a cell culture model of the blood-brain barrier (BBB) consisting of a coculture of brain capillary endothelial cells and astrocytes that closely mimics the in vivo situation. The permeability of albumin, a marker of the nonspecific transcellular route, is extremely low in this in vitro model of the BBB. After hypoxia, a huge increase in the permeability of albumin is detected. Despite the opening of the tight junctions already demonstrated after hypoxia, the increase in the permeability of albumin is mainly attributed to an increase of the nonspecific vesicular transport in the cell, attested by the temperature dependence of the phenomenon and the visualization of labeled apotransferrin in the cytoplasm. The increase of this pathway could participate in the development of brain edema during hypoxia. 相似文献
62.
Ghislaine Le Prince Pia Delaere Christiane Fages Thierry Lefrançois Monique Touret Marcelle Salanon Marcienne Tardy 《Neurochemical research》1995,20(7):859-862
Glutamine synthetase (GS), a metabolic marker of the mature astrocyte, was investigated in the temporal neocortex of postmortem brain samples of 8 cases, either not demented or affected by senile dementia of the Alzheimer type. A negative correlation between the GS protein level and the density of both classical A4 deposits and senile plaques was evidenced. Such a correlation for GS underlies a dysfunction of the astroglial metabolism and particularly of the glutamate and ammonia neutralization. Since GS is sensitive to oxidative lesioning, the changes in GS level that were observed, occurring at the posttranslational stage, might reflect oxidative damage and have severe consequences on the pathological cascade of events. 相似文献
63.
Myriam Calonje Concepción García Mendoza Amelia Pérez Cabo Monique Novaes-Ledieu 《Current microbiology》1995,30(2):111-115
Significant differences in gross wall chemical composition were detected in four commercial Agaricus bisporus strains. All were grown under the same conditions and their walls prepared by a mild method of breakage. A more detailed analysis of the wall fractions, isolated by means of their distinct solubilities, also showed striking structural differences among the four strains studied. The detected differences, not only in the overall composition of the wall but also in the polysaccharide structure, could assist in the characterization of strains and/or varieties of the commercial basidiomycete A. bisporus. 相似文献
64.
Jacqueline Besson Monique Dussaillant Jean-Claude Marie William Rostene Gabriel Rosselin 《Peptides》1984,5(2):339-340
This paper describes the autoradiographic distribution of VIP binding sites in the rat central nervous system using monoiodinated 123I-labeled VIP. High densities of VIP binding sites are observed in the granular layer of the dorsal dentate gyrus of the hippocampus, the basolateral amygdaloid nucleus, the dorsolateral and median geniculate nuclei of the thalamus as well as in the ventral part of the hypothalamic dorsomedial nucleus. 相似文献
65.
Asymptotic solutions for the effectiveness factor and the concentration profile are obtained for mth-order chemical reactions inside a slab catalyst pellet with Robin boundary condition at the pellet's outer surface. Using perturbation analysis in the limit of large reaction order m, the effectiveness factor and the concentration profile are explicitly determined up to O(1/m). Higher-order solutions can be obtained in a systematic way if desired. 相似文献
66.
The DNA content of plants which were sampled in natural di-, tetra- and hexaploid populations of Hippocrepis comosa L. was estimated and the aspartate transcarbamylase activities of the corresponding cell-free extracts were compared. The amount of DNA is not exactly proportional to the number of genomes. The three kinds of populations do not differ in their aspartate transcarbamylase specific activity. While the enzyme properties are identical in the extracts derived from the diploid and hexaploid plants, the aspartate transcarbamylase present in the tetraploid cytotype shows a slightly lower affinity for one of its substrates and a significantly lower sensitivity to the feedback inhibitor UTP which is still observed after partial purification. These properties might be related to the previously reported greater ability of the tetraploid cytotype to adapt to a variety of biotopes.Abbreviations ATCase
aspartate transcarbamylase
- CAP
carbamylphosphate
- EDTA
ethylenediaminetetracetic acid
- Tris
trihydroxymethylaminomethane
- AMP
adenosine monophosphate
- ATP
adenosine triphosphate
- CMP
cytidine monophosphate
- CTP
cytidine triphosphate
- UMP
uridine monophosphate
- UTP
uridine triphosphate 相似文献
67.
Jean-Jacques Madjar Monique Arpin Monique Buisson Jean-Paul Reboud 《Molecular & general genetics : MGG》1979,171(2):121-134
Summary Separation of the proteins from rat liver 40S and 60S ribosomal subunits and polysomes was done in four different two-dimensional polyacrylamide gel electrophoresis systems. The first dimension was run at acidic or basic pH, the second dimension either with sodium dodecyl sulphate or at acidic pH in 18% acrylamide. The position of each individual protein of both subunits and polysomes was determined in each system. This identification resulted from a new method avoiding any previous purification of individual proteins. The new proposed uniform nomenclature for mammalian ribosomal proteins (McConkey et al. in press) was used for numbering the proteins in the four systems. 相似文献
68.
Monique Bedin Dominique Weil Thérèse Fournier Lise Cedard Jean Frezal 《Human genetics》1981,59(3):256-258
Summary Steroid sulfatase activities are significantly higher in placentas obtained after the birth of girls than after the birth of boys, and also in female fibroblasts compared to male strains. This constitutes biochemical evidence for the non-inactivation of the X-linked sulfatase locus. No hydrolytic activity is found in the fibroblasts of ichthyotic boys. Heterozygosity is demonstrated in the fibroblasts of the four mothers studied, as they have steroid sulfatase activity of less or equivalent to the normal male value. 相似文献
69.
Enzymes are often immobilized on the internal surfaces of porous solid by immersing enzyme-free particles in a well mixed solution of enzyme. The ensuing impregnation process involves coupled transient mass transfer and surface attachment of enzyme. A mathematical model is employed to explore the influences of process parameters on the amount of enzyme loaded and the distribution of immobilized enzyme within the support particles. Nonuniform loading of the support occurs under some conditions. This is significant since the distribution of enzyme within the support particle influences the overall activity and stability of the immobilized enzyme catalyst. The model developed here may also be used to describe removal of reversibly immobilized enzyme during washing or utilization of the immobilized enzyme catalyst. 相似文献
70.
Monique Decastel Anh-Tuan Tran Jean-Pierre Frénoy 《Biochemical and biophysical research communications》1982,106(2):638-643
The binding of 4-methylumbelliferyl-α-D-galactopyranoside, -β-D-galactopyranoside and -D-Galβ(1→3)DGalNac to peanut agglutinin was studied by fluorescence. Peanut agglutinin quenched the fluorescence intensity of 4-methylumbelliferyl-α-D-galactopyranoside but enhanced that of the two 4-methylumbelliferyl-β-galactosides. For α-D-galactopyranoside, the association constants measured at 4 and 25°C were 3.4 × 103 and 1.7 × 103 M?1 respectively, and for D-Galβ(1→3)DGalNac, 1.5 × 105 and 3.3 × 104 M?1. The binding enthalpies estimated from these values are consistent with the existence of extended sugar binding sites in the peanut agglutinin molecule. 相似文献