PubMed Health⌕ Search

Biomedical subjects

M Kuba

Publications and source records attributed to M Kuba.

At least 19 recordsLinked to original sources
PubMed1992

Characterization of N omega-phosphoarginine hydrolase from rat liver.

N omega-Phosphoarginine hydrolase from rat liver hydrolyzed N omega-phosphoarginine into arginine and inorganic phosphate, whereas it did not release inorganic phosphate from 19 other phosphorylated compounds containing a N-P bond, an O-P bond or a C-P bond. In addition, it was not able to transfer the phosphoryl moiety from N omega-phosphoarginine to ADP. These results indicated that this enzyme was distinct from both phosphoamidase and arginine kinase. Its properties were as follows: thiol compounds were essential for its activity; it was stimulated by 1.5-2-fold in the presence of 0.001% Lubrol, Tween 20, poly(oxyethylene) 9-lauryl ether and Nonidet P-40, while 0.004% sodium lauryl sulfate inhibited the activity completely; concentrations of sodium molybdate and sodium vanadate necessary for 50% inhibition were 7 microM and 12 microM, respectively; some proteins stimulated the activity, while lysophosphatidic acid, lysophosphatidylinositol, and phosphatidic acid suppressed the activity even in the presence of poly(oxyethylene) 9-lauryl ether.

Animals↗
PubMed1992

Clinical application of motion-onset visual evoked potentials.

The results of motion-onset visual evoked potentials and pattern-reversal visual evoked potentials were compared in 5 adults with amblyopia, in 13 patients with unilateral retrobulbar neuritis and in 62 patients with multiple sclerosis. While the pattern-reversal visual evoked potentials had reduced amplitudes and prolonged latencies in all amblyopic eyes, the motion-onset visual evoked potentials were normal. Thus, motion-onset visual evoked potentials cannot be used for diagnosis of amblyopia. In patients with retrobulbar neuritis, both types of visual evoked potentials were delayed on stimulation of the affected eye. The latency increase was, however, greater for pattern-reversal visual evoked potentials than for motion-onset visual evoked potentials. Examination of the patients with multiple sclerosis showed that the additional use of motion-onset visual evoked potentials increased the sensitivity of the investigation. In some patients, only the motion-onset visual evoked potentials had pathologic latency increases, whereas the pattern-reversal visual evoked potentials stayed within normal limits.

Adult↗
PubMed1992

Visual evoked potentials specific for motion onset.

Motion-onset visual evoked potentials were studied in 140 subjects by means of motion-onset stimulation either on a television screen or through back projecting via a moving mirror. The motion-onset visual evoked potentials were characterized in 94% of the population by a dominant negative peak with latency in the range of 135-180 ms. Motion-onset visual evoked potentials with a dominant positive peak, as described in the literature, seemed to be a variant of pattern-off visual evoked potentials, caused by the pattern-disappearance effect at the onset of motion with a high temporal frequency (the multiple of the spatial frequency of the structure and the velocity of motion) of more than 6 Hz. Such visual evoked potentials occur mainly when the stimulus is limited to the macular area only. Additionally, other stimulus and recording conditions were found to be suitable for acquiring the specific motion-onset potentials without their contamination by pattern-related components. These conditions were as follows: an aperiodic moving pattern (e.g., random dots) with a low contrast (less than 0.2); a short duration of motion (less than or equal to 200 ms) and a sufficient interstimulus interval (at least five times longer than the motion duration) to decrease the adaptation to motion; and extramacular stimulation and recording of visual evoked potentials from unipolar lateral occipital leads. Such leads should be used because of the lateralization of these visual evoked potentials (mainly to the right occipital area), which is consistent with their assumed extrastriate origin.

Adult↗
PubMed1992

Motion-reversal visual evoked responses.

Motion-reversal visual evoked responses (VERs) have remarkable waveform variability. In our opinion this is caused by the alternative predominance of either motion or pattern-onset/offset related components. The motion dependent component of motion-reversal VER closely resembles motion-onset VER (main negative peak with the latency of about 170 ms), the first positive peak (with the latency of about 100 ms) corresponds to the pattern-onset component and the second non-constant positive peak (with the latency of about 130 ms) seems to be identical with the pattern-offset positivity. The differences in expression of these components are dependent on some stimulus characteristics (mainly on the contrast of a structure, velocity of motion, retinal localization of the stimulus) and on substantial differences in the sensitivity of subjects to motion stimulation.

Adolescent↗
PubMed1992

[Evoked visual responses in schizophrenic patients].

The authors investigated during prolonged ambulatory treatment with the neuroleptic preparation isofloxythepine (IFT) changes of visually induced responses in 24 psychotic patients. The reference group was formed by 10 healthy volunteers examined before and after administration of a single dose of IFT by the oral route. In addition to the visually induced responses the authors investigated also plasma prolactin levels (PRL). It was found that the latency of the P1 peak and amplitude between peaks A1 are in psychotic patients altered, as compared with healthy subjects. The latency of the P1 peak is after a single dose of IFT in healthy subjects longer and the amplitude A1 higher than in the sick group. In healthy subjects after administration of IFT a negative correlation was observed between the amplitude and the basal PRL level. In patients no relationship was found between PRL levels and parameters of the visually induced response.

Adult↗
PubMed1992

[Concentration of Fe, Fe-binding capacity, Cu and Zn in the plasma of piglets before and after oral administration of iron sulfate solution].

In piglets, the influence of the ingestion of Fe-enriched faeces, of the oral application of Fe-dextran (containing 150, 200 or 250 mg Fe) up to the 8th hour as well as the intramuscular injection of Fe-dextran (150 mg Fe) on the 2nd and 3rd day after birth on Fe-resorption was analysed. On the 5th to the 7th and on the 12th to the 14th day after birth the highest increase in the Fe-concentration and the highest values of the Fe-binding capacity of the plasma after the oral application of a solution of Fe-sulphate (containing 20 mg Fe/kg body weight) were confirmed in the piglets with the ingestion of Fe-enriched faeces and in the control piglets without Fe-supplementation. The increase of the iron concentration in the plasma induced a decrease in the concentration of Cu in some cases and of Zn in the plasma in most cases. The biggest increase in body weight was established in the piglets that ingested Fe-enriched faeces.

Administration, Oral↗
PubMed1992

[Visual evoked potentials. Their use in ophthalmology and other specialties].

The technique of investigating evoked visual potentials (EVP) is resumed within the context of electrophysiological methods as applied in optic neuritis. Several typical courses of the disease are case-reported in this account. In conclusion, authors recommend further on EVP implications due to its objectivity, non-invasiveness and time-sparing with a possible automated evaluation.

Adult↗
PubMed1990

Properties of visual evoked potentials to onset of movement on a television screen.

In 80 subjects the dependence of movement-onset visual evoked potentials on some measures of stimulation was examined, and these responses were compared with pattern-reversal visual evoked potentials to verify the effectiveness of pattern movement application for visual evoked potential acquisition. Horizontally moving vertical gratings were generated on a television screen. The typical movement-onset reactions were characterized by one marked negative peak only, with a peak time between 140 and 200 ms. In all subjects the sufficient stimulus duration for acquisition of movement-onset-related visual evoked potentials was 100 ms; in some cases it was only 20 ms. Higher velocity (5.6 degree/s) produced higher amplitudes of movement-onset visual evoked potentials than did the lower velocity (2.8 degrees/s). In 80% of subjects, the more distinct reactions were found in the leads from lateral occipital areas (in 60% from the right hemisphere), with no correlation to handedness of subjects. Unlike pattern-reversal visual evoked potentials, the movement-onset responses tended to be larger to extramacular stimulation (annular target of 5 degrees-9 degrees) than to macular stimulation (circular target of 5 degrees diameter).

Adult↗
PubMed1990

Visually evoked potentials in response to rotating plane-polarized blue light.

Visually evoked cortical potentials closely related to the appearance and disappearance of Haidinger's brushes were obtained in response to onset and offset of rotation of plane-polarized blue light. The method provides a means of investigating macular function in man; it is fairly independent of ocular opacities and relates, for the first time, entoptic phenomena to those evoked by extrinsic light stimulation.

Adult↗
PubMed1990

[Practical output of the results of computerized EEG frequency analysis].

For the practical application of EEG frequency analysis it is necessary to ensure an output of results which contains only clinically relevant data. The article describes a new solution where, based on adequate statistical evaluation of parameters of frequency spectra, only important facts are topographically visualized. Marked reduction of data thus makes it possible to concentrate useful information. Contrary to hitheric common "mapping" of electric activity of the brain, it is thus easier to detect pathological changes in the EEG frequency spectra.

Electroencephalography↗
PubMed1989

A basic protein from bovine brain that co-precipitates with tubulin in vitro.

A 193 kDa protein consisting of 58 kDa subunits, which has pI values of 8.50 and 8.65, was purified from bovine brain cytosol. It formed heavy precipitates with tubulin, and the molar ratio of tubulin dimer to this protein in the precipitate was 3.2. In contrast to microtubules containing ordinary microtubule-associated proteins, these complexes remained stable against cold and 1 mM CaCl2.

Animals↗
PubMed1989

[The pathophysiologic basis for the incorporation of 99mTc-pyrophosphate into myocardial infarct].

The investigation studied the relation of 99mTc-pyrophosphate incorporation (99mTc-PYP) into experimental, 48-hours old myocardial infarction in dogs to tissue vascular supply and to the extent of necrotic tissue. The experimental myocardial infarction was induced in five animals during an operation by the ligation RIVA. The myocardial blood supply was measured in tissue samples, taken from transverse sections of the infarction by means of 86Rb captation. The extent of myocytolysis was measured by depletion of tissue creatine kinase (CK). In the subendocardial layer of the infarction it became obvious that 99mTc-PYP incorporation was proportional to the decrease of tissue blood supply. No relation between the extent of necrosis and the incorporation of the radioactive chemical was demonstrated. The accumulation of 99mTc-PYP requires the necrosis to be present, but its extent apparently does not influence the intensity of incorporation. In the subepicardial infarction layer there was neither a relation of the radioactive chemical cumulation to the blood flow, nor to the extent of the necrosis proved.

Animals↗
PubMed1989

[The visual evoked response at the onset of structural movement].

Stimulation by means of moving the structure in the visual field is used to produce visual evoked responses (VER) only rarely. The authors attempted to verify the fact how VER to the movement depended on some stimulation parameters and to compare them with VER to the most frequently used stimulation method, i. e. reversal. Horizontally moving black and white vertical stripes were used with special frequency 2.3 cycles/deg on the screen. It was found that at least 3s interval between two stimuli (between the end of the preceding and onset of the following movements) was necessary and sufficient period of the moving was about 100 ms. Resultant VER are then a reaction on the onset of the movement and are characterized mostly only by marked negative peak with latency being 140 to 200 ms. Opposite to reversal VER, those to the onset of the movement were obtained just in 87.5% of the persons examined (n = 40), in five cases, however, the response to the onset of the motion was higher than that to reversal VER amplitudes were in the latter case highest in the unipolar lead from the right occipital region with the rate of the structure movement being 42 to 84 mm/s.

Evoked Potentials, Visual↗
PubMed1988

99mTc-aminohexylidendiphosphonate and 99mTc-pyrophosphate in the scintigraphic diagnosis of experimental myocardial infarction in dogs.

99mTc-aminohexylidendiphosphonate (99mTc-AHDP) is a new Czechoslovak pharmaceutical of the phosphonate line which contains the amino group NH2 in its molecule. This substance was tested in 5 dogs with experimentally provoked 48-h old myocardial infarction. The in-vivo scan and the radioactivity of tissue samples demonstrated that 99mTc-AHDP is as suitable for imaging acute myocardial infarction as is the commonly used 99mTc-pyrophosphate.

Animals↗