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51.
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L G Shapre J W Olney C Ohlendorf A Lyss M Zimmerman B Gale 《Pharmacology, biochemistry, and behavior》1975,3(2):291-298
L-cysteine in doses of 1.2-1.3 mg/g, was administered to 4-day-old rats which were tested throughout development and as adults on a variety of behavioral tasks. Lesions of the type previously described from L-cysteine treatment were confirmed in several cortical and limbic structures. No neurodegenerative changes were observed in NaCl (10 mmoles/kg) controls. Surviving L-cysteine treated animals displayed no obvious impairments in motor ability or growth rate, but did show behavioral deficits when tested as adults on 3 behavioral tasks: spontaneous alternation; Lashley III maze; and pattern discrimination. Activity in the open field was significantly higher in the L-cysteine group at 20 days of age. Amphetamine, administered in doses of 1.5 to 3.0 mg/kg, had no differential effects on open-field activity in the two groups. The behavioral changes observed in L-cysteine treated animals is similar to that which has been reported in adult rats with extensive hippocampal damage. 相似文献
53.
The quality of low-contrast portal radiographs for radiation therapy can be improved with electronic contrast enhancement. After the image is copied digitally with a laser scanner microdensitometer into 4,096 gray-scale levels (12 bits) and 1,686 X 2,048 pixels, a special software package permits linear, logarithmic, exponential, or sigmoid transformations of the optical density. The precise representation of the portal image can then be interactively adjusted to emphasize the desired anatomy. Clinical examples demonstrate the value of the digital enhancement approach. 相似文献
54.
Spacing of cytochrome oxidase blobs in visual cortex of normal and strabismic monkeys 总被引:3,自引:3,他引:0
Murphy KM; Jones DG; Fenstemaker SB; Pegado VD; Kiorpes L; Movshon JA 《Cerebral cortex (New York, N.Y. : 1991)》1998,8(3):237-244
Some models of visual cortical development are based on the assumption that
the tangential organization of V1 is not determined prior to visual
experience. In these models, correlated binocular activity is a key element
in the formation of visual cortical columns, and when the degree of
interocular correlation is reduced the models predict an increase in column
spacing. To examine this prediction we measured the spacing of columns, as
defined by cytochrome oxidase (CO) blobs, in the visual cortex of monkeys
whose binocular vision was either normal or disrupted by a strabismus. The
spatial distribution of blobs was examined in seven normal and five
strabismic macaques. Tangential sections through the upper layers of the
visual cortex were stained to reveal the two-dimensional (2D) pattern of CO
blobs. Each blob was localized and their center-to-center spacing, packing
arrangement and density were calculated using 2D nearest-neighbor spatial
analyses. The mean center-to-center spacing of blobs (590 microm for
normally reared and 598 microm for strabismic macaques) and the mean
density of blobs (3.67 blobs/mm2 for normally reared and 3.45 blobs/mm2 for
strabismic macaques) were not significantly different. In addition, the 2D
packing arrangement of the blobs was not affected by strabismus. While it
is clear that neural activity plays a key role in the elaboration and
refinement of ocular dominance cortical modules, we conclude that it does
not determine the spatial period of the pattern of CO blobs. This suggests
that aspects of the neural circuitry underlying the columnar architecture
of the visual cortex are established prenatally and its fundamental
periodicity is not modifiable by experience.
相似文献
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Fc and C3 Receptors Induced by Herpes Simplex Virus on Cultured Human Endothelial Cells 总被引:27,自引:5,他引:22 下载免费PDF全文
Douglas B. Cines Alan P. Lyss Mahin Bina Richard Corkey Nicholas A. Kefalides Harvey M. Friedman 《The Journal of clinical investigation》1982,69(1):123-128
The mechanism by which immune complexes deposit in vascular tissue is uncertain. Several human viruses, including herpes simplex virus, have recently been demonstrated to replicate in human endothelial cells. Such viruses may injure vascular tissue and could play a role in the pathogenesis of immune complex deposition. Therefore, we studied the expression of receptors for immune complexes containing IgG and C3 on endothelial cells after infection with herpes simplex virus type I. 相似文献
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Decreased expression of phospholipase C-beta 2 isozyme in human platelets with impaired function 总被引:4,自引:4,他引:4
Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC- gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC- delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function. 相似文献