The pattern-reversal (P-VEPs) and the motion-onset (M-VEPs) of visual evoked potentials were modeled by means of three damped oscillators (O1, O2, O3) of identical construction. The O1, assumed to simulate the response of primary visual area (V1), was driven by the firing density of the lateral geniculate nuclei. O1 contributed mainly to the N75 and P100 peaks of the P-VEPs. The O2, driven by the O1 output, mimics the activity of V2, V3a, and MT. It contributed to the negative peak N145 of the P-VEPs or to the N160 in the M-VEPs. The O3 was suggested to model late slow processes probably of an attentive origin. The model parameters were set by optimization to follow the P-VEPs and M-VEPs obtained as a grand average of four young volunteers (PZ - A2 lead). The evoked potentials were described with normalized root mean square error lower than 13 %., J. Kremláček, M. Kuba, J. Holčík., and Obsahuje bibliografii
Studie Jany Spáčilové se zabývá mešními kompozicemi hudebního skladatele Antonia Caldary, dochovanými v moravských hudebních sbírkách., This article is dedicated to the problem of the erroneous attribution of authorship of Masses to Antonio Caldara in Moravian collections of church music. It contains information about extant records of Masses by Caldara and methodological discussion concerning the reliability of sources with respect to authorship. Also included is an overview of Caldara sources of Moravian provenience, including both extant music and entries in period inventories. Attention is dedicated both to compositions by others regarded in Moravia as works by Antonio Caldara, and to works by Caldara under the names of other composers. Works identified as having been written by other composers are presented in the form of tables, including signatures of all concordant sources found so far in European libraries. The purpose of the article is to give an idea of the standing of Caldara’s works in the repertoire of Moravian church music and to prepare material for a future thematic catalog of Moravian sources of Masses by Caldara., Jana Spáčilová., Rubrika: Studie, and Anglické resumé na s. 75, anglický abstrakt 45.
Growth of the A549 cell line in a perfusion system suitable for use in a magnetic resonance study has been characterized and shown to be stable physiologically and hence appropriate for serial observations. Several methods of monitoring cell growth were compared to assess the behavior of the cells in this system. Comparison between NMR metabolite data and cell growth via cell counting showed that 31P NMR signals accurately reported cell doubling time. In contrast to most NMR cell culture systems, viable cells can be recovered from the perfusion system after the NMR measurements for further biochemical studies. These data further suggest that this system will be useful for studying the physiology and biochemistry of exponentially growing cells for at least two days in NMR tube culture., E. G. Shankland, J. C. Livesey, R. W. Wiseman, K. A. Krohn., and Obsahuje bibliografii
Myofibrillar creatine kinase (CK) that buffers ATP during fluctuating muscle energy metabolism has been selected for studies of conformational changes underlying the cellular control of enzyme activity. The force field was computed for three energetic states, namely for the substrate-free CK molecule, for the molecule conjugated with the MgATP complex, and for the molecule conjugated with the pair of reactants MgATP-creatine. Without its substrates, the enzyme molecule assumes an inactive "open" form. Upon binding of the MgATP complex, the CK molecule takes up a reactive "closed" conformation. Subsequent binding of creatine yields a nonreactive "intermediary" conformation. Acid-base catalysis is considered to be the basic principle for the reversible transfer of the phosphoryl group between the substrates. The results indicate that the substrate-induced energy minimizing conformational changes do not represent a sufficient condition for CK activity and that some other essential component of physiological control at the cellular level is involved in the transition from the intermediary to the closed structure of the molecule., J. A. Mejsnar, B. Sopko, M. Gergor., and Obsahuje bibliografii
V článku je předložen model narativní komplexity. Jako východiska modelu jsou využity Todorovův pojem „narativní transformace“ a Brunerův koncept „potíž“. Narativní transformace je chápána jako to, „co vyprávění dělá s konstitutivní potíží“. S využitím těchto pojmů je narativní komplexita definována jako diferenciace a integrace různých aspektů narativní transformace. Pojem narativní komplexita poukazuje jak k dispozici, tak také k procesu i výsledku narativního ztvárnění zkušenosti v její složitosti, úplnosti a proměnlivosti. Model umožňuje včlenit do jednoho logicky konzistentního rámce různé aspekty narativní komplexity, tak jak byly doposud koncipovány z různých dílčích teoretických či praktických hledisek. Předložený model sestává z osmi souvisejících aspektů: 1) diferenciace a integrace tématu vyprávění, 2) diferenciace a integrace aktérství, 3) diferenciace a integrace narativní konstrukce, 4) diferenciace a integrace ztvárnění hodnot a přesvědčení, 5) diferenciace a integrace na rovině reflexe, 6) diferenciace a integrace hledisek a perspektiv, 7) diferenciace a integrace utváření postav, 8) diferenciace a integrace na rovině komunikačního a sociokulturního kontextu. Na závěr jsou zmíněny některé teoretické a empirické možnosti předloženého modelu., Model of narrative complexity is articulated. Todorov’s concept of “narrative transformation” and Bruner’s concept of “trouble” are used as a frame of narrative complexity conceptualization. Narrative transformation is presented as “something what story telling does with constitutive trouble”. Narrative complexity is thus defined as a differentiation and integration of various aspects of narrative transformation. Narrative complexity refers both to disposition and also to the process and to the result of narrative experience constructing in its complicatedness, completeness, and changeableness. The model enables to incorporate various aspects of narrative complexity from different theoretical and practical perspectives into one consistent framework. The presented model consists of eight interconnected aspects: 1) differentiation and integration of topic storytelling, 2) differentiation and integration of agency, 3) differentiation and integration of narrative construction, 4) differentiation and integration of values and believes embodiment, 5) differentiation and integration at the level of reflection, 6) differentiation and integration of different perspectives, 7) differentiation and integration of characters (protagonists), 8) differentiation and integration in communication and socio-cultural contexts. Theoretical and empirical consequences of the model are also discussed., Vladimír Chrz, Ivo Čermák., and Obsahuje seznam literatury
a1_The effect of lesions induced by bilateral intracerebroventricular (ICV) injection of quinolinate (250 nmol of QUIN/ventricle), a selective N-methyl-D-aspartate (NMDA) receptor agonist, on [3H]glutamate ([3H]Glu) binding to the main types of both ionotropic and metabotropic glutamate receptors (iGluR and mGluR) was investigated in synaptic membrane preparations from the hippocampi of 50-day-old rats. The membranes from QUIN injured brains revealed significantly lowered binding in iGluR (by 31 %) as well as in mGluR (by 22 %) as compared to the controls. Using selected glutamate receptor agonists as displacers of [3H]Glu binding we found that both the NMDA-subtype of iGluR and group I of mGluR are involved in this decrease of binding. Suppression of nitric oxide (NO) production by NG-nitro-L-arginine (50 nmol of NARG/ventricle) or the increase of NO generation by 3-morpholinylsydnoneimine (5 nmol of SIN-1/ventricle) failed to alter [3H]Glu or [3H]CPP (3-((D)-2-carboxypiperazin-4-yl)-[1,2-3H]-propyl-1-phosphonic acid; NMDA-antagonist) binding declines caused by QUIN-lesions. Thus, our findings indicate that both the NMDA-subtype of iGluR and group I of mGluR are susceptible to the QUIN-induced neurodegeneration in the rat hippocampus. However, the inhibition of NO synthesis did not reveal any protective action in the QUIN-evoked, NMDA-receptor mediated decrease of [3H]Glu binding., a2_Therefore, the additional mechanisms of QUIN action, different from direct NMDA receptor activation/NO production (e.g. lipid peroxidation induced by QUIN-Fe-complexes) cannot be excluded., V. Lisý, F. Šťastný., and Obsahuje bibliografii
Portal-systemic shunting is an important circulatory abnormality in patients with liver cirrhosis. Glyceryl trinitrate (GTN) that is normally subject to first pass elimination, may exhibit higher bioavailability in these patients. This study compares the pharmacodynamic effects of GTN after peroral and sublingual administration for noninvasive assessment of shunting. Six control subjects and 15 patients with cirrhosis were studied after oral and sublingual application of 0.5 mg of GTN. Liver cirrhosis was complicated by portal hypertension in 7 of the patients and 4 patients had surgically implanted portocaval anastomosis. Digital plethysmography, which is highly sensitive and is essentially noninvasive in nature, was used to assess and compare the pharmacodynamic effects of GTN. The following values of the ratio of areas under the pharmacodynamic effects/time curve were obtained: 0.08±0.06 in healthy subjects, 0.52±0.21 in patients with uncomplicated cirrhosis, 0.99±0.34 in patients with portal hypertension and 1.24±0.43 in patients with portal-systemic shunts. We conclude that increased bioavailability of GTN reflects portal-systemic shunting and might be used providing that the pharmacodynamic data reflect both pharmacokinetic variability and the pharmacokinetic-pharmacodynamic interrelations., O. Slanař, J. Aubrecht, F. Perlík., and Obsahuje bibliografii