Visual cognitive responses (P300) to moving stimuli were tested in 36 subjects with the aim to find the normal range of P300 parameters. Concomitantly, the circadian intra-individual variability of the P300 was studied in a subgroup of 6 subjects. Visual stimuli consisted of either coherent (frequent stimulus) or non-coherent motion (random stimulus). The oddball paradigm was applied for recording cognitive responses. P300 to rare stimuli had an average latency of 447.3±46.6 ms and amplitude of 12.9±6.0 mV. The average reaction time was in the range from 322 to 611 ms and there was no correlation between the reaction time and P300 latency. We did not find any significant circadian changes of the P300 parameters in the 6 subjects tested four times during the same day. Cognitive (event-related) responses (P300) displayed distinctly greater inter-individual variability (S.D. of 50 ms) when compared with pattern-reversal and motion-onset VEPs (S.D. of 6.0 ms and 14 ms, respectively). For this reason, the clinical use of P300 elicited by this kind of visual stimuli seems to be rather restricted and the evaluation of its intra-individual changes is preferable., Z. Kubová, J. Kremláček, J. Szanyi, J. Chlubnová, M. Kuba., and Obsahuje bibliografii
Some recent studies on dyslexia have suggested a selective abnormality in the magnocellular visual pathway. To verify this hypothesis, we investigated motion-onset visual evoked potentials (VEPs) (predominantly testing the magnocellular system) as well as pattern-reversal VEPs (presumably testing the parvocellular system) in 20 dyslexics and 16 controls (both groups with a mean age of 10.0 years). Although the latencies and amplitudes of the main positive peak of pattern-reversal VEPs did not differ between the dyslexic and control group, the motion specific negative peak of motion-onset VEPs was significantly delayed (p<0.001) in dyslexics. Our results confirm a selective magnocellular pathway disorder in dyslexics and indicate that the motion-onset VEPs might serve as an objective method for early diagnosis of dyslexia.
The purpose was to test parameters of visual evoked potentials (VEPs) and of event-related potentials (ERPs) in deaf subjects to verify visual and cognitive CNS functions in a handicapped group of the population. Three types of visual stimuli (with dominating parvocellular or magnocellular system activation or with cognitive tasks) were used in the study. Six deaf persons (4 women, 2 men, mean age 17 years) and 6 persons with normal hearing (sex- and age-matched) were included in this pilot study. In all types of stimulation, latencies and amplitudes of main VEPs and ERPs components were evaluated. No significant latency differences were found. However, significantly reduced amplitudes were found in the occipital area for responses to motion and cognitive stimuli which might be interpreted as a part of functional reorganization of the extrastriate and cognitive cortical areas of deaf subjects.
Based on the fact that tremors display some distinct 3D spatial
characteristics, we decided to visualize tremor planes in 3D
space. We obtained 3-axial linear accelerometer signals of hand
tremors from 58 patients with Parkinson´s disease (PD), 37 with
isolated resting tremor (iRT), 75 with essential tremor (ET), and
44 healthy volunteers with physiological tremor (Ph). For each
group analysis was done with subsequent spatial 3D regression
of the input data i.e. along the x, y and z axes; the projected
vector lengths in the individual (vertical transversal XY, vertical
longitudinal XZ and horizontal YZ) reference frame planes and
their angles. Most meaningful and statistically significant
differences were found in the analyses of the 3D vector lengths.
The tremor of the PD and the iRT group was oriented mainly in
the horizontal YZ plane. The tremors of the patients with ET and
Ph were oriented approximately in the midway between the all
three referential planes with less tilt toward the vertical
longitudinal XZ plane.
The West Bohemia earthquake swarm foci are approximated by a circular seismic source model, which radius is assumed to depend only on magnitude of the event. We consider two different models of average slip (i) a constant slip and (ii) a slip exponentially scaled to the magnitude of the event. Based on these assumptions, we stacked the contributions of individual events into representative final fault slip. We processed in such a way four significant swarms recorded during the last three decades in 1986, 1997, 2000 and 2008. Constant slip model indicates final slip was composed of 2 or 3 principal asperities located on one or two different planes. On the contrary, scaled slip model indicates that one big asperity prevails. It is not possible yet to select the preferred slip model. Analysis of the temporal activity of all swarms generally shows three principal phases: starting phase, main phase and fading phase; the upwards trend of activity spreading was observed (slip animation is presented in www supplement http://www.ig.cas.cz/kolar/StopPhase/Asperity). The maximal possible cumulative slip value may have reached the order of meters., Petr Kolář, Bohuslav Růžek, Alena Boušková and Josef Horálek., and Obsahuje bibliografii
Receptory pro vitamin D jsou přítomny téměř ve všech tkáních těla. Vitamin D nefunguje jen jako regulátor metabolizmu vápníku a fosforu, ale i jako látka modulující funkci imunitního systému, regulující proliferaci buněk. Genetická, epidemiologická a experimentální data nasvědčují pro možnou roli deficitu vitaminu D při vzniku některých chorob, především autoimunitních onemocnění a nádorů. Přínos léčebného podávání vitaminu D se doposud nepodařilo prokázat. Není důvod nehradit deficit vitaminu D. Substituce by měla začít úhradou chybějícího množství vitaminu D (řádově i několik set tisíc jednotek) s trvalým podávání doporučené substituční dávky 800–1 000 jednotek vitaminu D za den., Receptors for vitamin D are present almost in all body tissues. Vitamin D does not only act as a regulator of calcium and phosphorus metabolism, but also a substance which modulates the immunity system function, regulates cell proliferation. Genetic, epidemiological and experimental data indicate a possible role of vitamin D deficiency in the development of some diseases, mainly of autoimmune diseases and tumours. The benefit of curative intake of vitamin D has so far not been proven. There is no reason why the deficiency of vitamin D should not be covered. The substitution should start with the replenishment of the lacking amount of vitamin D (which may even be several hundred thousand units) and involve ongoing intake of the recommended substitution dose of 800–1 000 vitamin D units per day., and Vladimír Kojecký
In this review we summarize recent opinions on the possible role of vitamin D in the risk of thyroid diseases development. It may be concluded from the available data that vitamin D deficiency, particularly levels below 12.5 ng/ml should be considered as an additional, but important risk factor for development of thyroid autoimmunity, both chronic autoimmune thyroiditis and Graves´ disease. A higher risk of Graves´ disease development is also associated with several polymorphisms in the gene encoding for vitamin D binding protein and for the specific receptor of active form of vitamin D - 1,25-(OH)2D3 in the respective target cells. Important for development of thyroid cancer appeared polymorphisms of genes encoding for vitamin D receptors and of genes encoding for the participating hydroxylating enzymes in thyroid tissue, leading to a diminished local 1,25-(OH)2D3 formation capacity with following alteration of antiproliferatory, antiapoptotic and prodifferentiating efficacy of the latter. Whether supplementation with high doses of vitamin D or its analogues possesses preventive or therapeutic effect is an object of intensive studies., K. Vondra, L. Stárka, R. Hampl., and Obsahuje bibliografii
Reduced levels of vitamin or its metabolites have been reported in various psychiatric disorders. Insufficient levels of vitamin D in depressive patients have been confirmed by many authors, but there have been conflicting results in subjects with anxiety disorders. In the present cross-sectional study, levels of calcidiol were determined in groups of depressive men and women and in men and women with anxiety disorders and compared with age matched controls. Significantly lower levels of calcidiol were found in men and women with depression as well as in age matched patients with anxiety disorders., M. Bičíková, M. Dušková, J. Vítků, B. Kalvachová, D. Řípová, P. Mohr, L. Stárka., and Obsahuje bibliografii
Insufficient levels of vitamin D have been demonstrated by many
authors as a risk factor for autistic patients, however, the
causality has not been reliably elucidated. In the present study,
levels of calcidiol were determined in group of autistic children
and compared with age matched healthy children as controls.
Suboptimal levels of calcidiol in more than 60 % of both autistic
patients as well as of control group were found. No significant
differences in vitamin D between autistic children and healthy
controls were observed.