Sborníky

Sborníky Nalezeno 1,261 záznamů.  začátekpředchozí1034 - 1043dalšíkonec  přejít na záznam: Hledání trvalo 0.00 vteřin. 
Diffusion and MRS in a rat cortex after traumatic injury
Voříšek, Ivan ; Herynek, V. ; Burian, M. ; Hájek, M. ; Niclay, K. ; Syková, Eva
An increase in diffusion barriers, manifestes by a decrease of both ADCTMA and ADCW, occurs throughout the entire cortex of the wounded hemisphere. These changes are related to astrogliosis and to an accumulation of extracellular matrix molecules without significant changes in ECS volume.
Suppression of 2f1-f2 distortion product otoacoustic emissions by electrical stimulation of the inferior colliculus in guinea pigs
Popelář, Jiří ; Mazelová, Jana ; Syka, Josef
Electrical stimulation of certain parts of the IC resulted in the depression of the DPOAE amplitude by 0.1-2 dB. The value of maximal DPOAE suppression was similar to the DPOAE suppression produced by acoustical stimulation of the contralateral ear. Our results indicate that electrical stimulation of the external cortex of the IC can activate the efferent system and produce DPOAE suppression by similar mechanisms as does acoustical stimulation of the contralateral ear.
A behavioral and electrophysiological study of the effects of noise exposure on auditory function in rat
Rybalko, Natalia ; Mazelová, Jana ; Syka, Josef
The values of the gap detection threshold doubled after exposure to 110 dB SPL and quadrupled after exposure to 115-120 dB SPL. GDT recovered to the original values during 1-2 weeks. Increased gap detection thresholds after noise exposure appear connected with elevated hearing thresholds, the deterioration in the performance of some animals in behavioral rasts after strong intensity noise (120 dB SPL) may signal the occurrence of tinnitus in these animals.
Representation of communication sounds in the inferior colliculus of the guinea pig
Šuta, Daniel ; Kvašňák, Eugen ; Popelář, Jiří ; Syka, Josef
The spectrotemporal discharge patterns of the neuronal population were clearly related to the spectrotemporal acoustic patterns of vocalization sounds.This study provides evidence for encoding of the spoctrotemporal acoustic pattern of vocalization sounds in a spcific and distributed way by the firing patterns of a population of IC units.
Functional characteristics of neurons in the auditory thalamus
Kvašňák, Eugen ; Šuta, Daniel ; Popelář, Jiří ; Syka, Josef
The MGB, is similarly as the inferior colliculus (IC) is organized into three subdivisions, with the ventral MGB characterized by the quickest onset reaction with the lowest thresholds to auditory stimulation and with the same ratio of monotonic and non-monotonic RLFs.
NADPH-d - positive neurons in the auditory cortex of young and very old rats
Nwabueze-Ogbo, Fidel Chijoke ; Druga, R. ; Syka, Josef
In young and very old animals stained neurons were localized in layers II-VI and in the subcortical white matter. A significantly higher packing density of labeled supragranular layers. In very old animals the thickness of the auditory cortex and the neuronal density was reduced when compared to the young.
Peripheral and central changes of the auditory system in the elderly
Mazelová, Jana ; Popelář, Jiří ; Valvoda, Jaroslav ; Syka, Josef
We compared the hearing abilities of 15 elderly subjects with a group of 15 young normal hearing. The results of this study support the opinion of many other suthors that the problems of aged people do not result ohly from elevated audiometric thresholds, but also from processes of central oring.
Interaction between descending and ascending pathways in the auditory system
Syka, Josef
Inactivation of the AC resulted in changes in the latency and amplitude of some parts of click-evoked IC responses and in either an increase or decrease in the firing rate of IC neurons in comparison with normal control conditions. The interaction of ascending and descending pathways in the auditory system may contribute to better frequency tuning, suppression of non-relevant acoustical signals and concentration of our attention on specific signals (for example the voice of the speaker.)
24-Epibrassinolide at Subnanomolar Concentrations Modulates Growth of Mouse Hybridoma Cells
Franěk, František ; Kohout, Ladislav ; Eckschlager, T.
Brassinolides are known to stimulate plant growth and to posses antistresiTactivities in plants. This work was aimed at exploring possible beneficial effects of 24-epibrassinolide on cultured mammalian cells. A mouse hybridoma, i.e. a hybrid ymphocyte cell line, was cultured either in standard serum-free medium, or in diluted medium in which the cell grew inder nutritional stress. Steady-state parameters of semicon-finuous cultures conducted at 24-epibrassinolide concentra-ions from 10~16 M to 1CT9 M were evaluated. Typical effects of he agent that were observed both in standard and in diluted i [media were suppression of intracellular antibody level, increa- / ,ed value of mitochondrial membrane potential, higher frac- / ion of cells in the G(/Gl phase and lower fraction of cells in / he S phase. Alleviation of nutritional stress was observed in j (cultures conducted in diluted media. Viable cell density was j ignificantly higher at 24-epibrassinolide concentrations 10~13[ knd 10~12 M. Results of this exploratory study show that thej plant hormone 24-epibrassinolide may induce alterations of he cell division mechanism of the energetic metabolism, and of secreted protein synthesis in a mammalian cell line.
Genetic Variability Between Different Isolates of Potato Mop-top Virus (PMTV)
Rosecká, Pavla ; Moravec, Tomáš ; Filigarová, Marie ; Dědič, P. ; Čeřovská, Noemi
We determined partial nucleotide sequences of several different field isolates of PMTV with well-characterized biological properties from the Czech Republic and Denmark. Subsequently we were trying to elucidate the correlation between nucleotide sequences of various isolates, their biological properties and geographical origin. From the comparison with other known sequences we can conclude, that PMTV genome is relatively conserved.

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