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M Kuba

Publications and source records attributed to M Kuba.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cognitive evoked potentials related to visual perception of motion in human subjects.

A method was tested for simultaneous recordings of evoked potentials from the secondary visual cortex (mediotemporal) and from the brain cognitive areas (fronto-central). Visual moving stimulations with cognitive tasks seem to be suitable for combined examination of visual motion perception and cognitive processes based on the magnocellular system activity. This arrangement enhances the analysis of visual information processing and evaluation of central nervous system functions.

Adult↗
PubMed1997

Molecular evolution of amphioxus fructose-1,6-bisphosphate aldolase.

The cDNA for amphioxus fructose-1,6-bisphosphate (FBP)-aldolase was isolated and its nucleotide sequence was determined. In the cDNA, there existed a probable open reading frame comprising 1080 bp; hence, 359 amino acid residues were deduced. The amino acid sequence indicates the deletion of 4 residues from N-terminus, in comparison with the sequence of FBP-aldolase isozymes from other sources. There was only one FBP-aldolase gene, and one enzyme species corresponding, in the amphioxus; this is the first report of the existence of a single FBP-aldolase species in animals. Enzymatic studies of both native and the recombinant FBP-aldolase suggest that the amphioxus enzyme belongs to an ancestral class I type which is not discovered among vertebrate aldolase isozymes.

Amino Acid Sequence↗
PubMed1997

UFT plus cisplatin in advanced non-small-cell lung cancer: interim analysis of 67 patients.

A single-institution phase II study indicated that combination chemotherapy using UFT (tegafur and uracil) plus cisplatin (Platinol) in patients with non-small-cell lung cancer was active with less host toxicity than other cisplatin-based therapies. To confirm these observations, the Japan JFT Lung Cancer Study Group conducted a multi-institutional phase II trial. The number of patients planned for this trial is 110. Eligibility includes previously untreated stage IIIB or IV non-small-cell lung cancer and a good performance status. UFT 400 mg/m2 in two divided doses is administered orally on days 1 through 14, and cisplatin 80 mg/m2 is injected IV on day 8. This treatment is repeated every 3 or 4 weeks. Between April 1995 and May 1996, 67 patients were enrolled, and all 67 were considered eligible for an interim analysis performed in October 1996. Among 63 patients evaluable for response, there was an overall response rate of 30% (95% confidence interval, 19% to 41%), with one complete response and 18 partial responses. With a median follow-up duration of 44 weeks, the median survival time was 32 weeks and the 1-year survival rate was 25%. Grade 3 leukopenia occurred in only 1 of 67 patients (1.5%), and there was no thrombocytopenia of grade 3 or greater. Vomiting, the most common nonhematologic toxicity observed, reached grade 3 or 4 in only 6 patients (9%). This interim analysis seems to support the observations of the previous single-institution phase II trial.

Aged↗
PubMed1996

Is the motion system relatively spared in amblyopia? Evidence from cortical evoked responses.

Visual evoked potentials (VEPs) produced by pattern reversal were compared with those elicited by onset of motion in 37 amblyopic children (20 with anisometropic amblyopia, seven with strabismic amblyopia and 10 with both anisometropia and strabismus). The amplitudes and peak latencies of the main P1 peak in the pattern-reversal VEP and of the motion-specific N2 peak in the motion-onset VEP through the amblyopic eye were compared with those through the normal fellow eye. Regardless of the type of amblyopia, the amplitude of the pattern-reversal VEP for full-field stimulation was significantly smaller and its latency significantly longer through the amblyopic eye (P < 0.001). In contrast, neither the amplitudes nor the latencies of the N2 motion-onset VEPs differed significantly between amblyopic and non-amblyopic eyes. For pattern-reversal VEPs through the amblyopic eyes, the extent to which amplitude was reduced and latency prolonged correlated well with the reduction of visual acuity, whereas the amplitudes and latencies of motion-onset VEPs did not vary with visual acuity. Even for stimuli restricted to the central visual field (5 or 2 deg diameter) or to the peripheral field (excluding the central 5 deg), motion-onset responses were indistinguishable through the two eyes, while pattern-reversal responses always differed significantly in amplitude. These results suggest that the source of motion-onset VEPs (probably an extrastriate motion-sensitive area) is less affected in amblyopia than that of pattern-reversal VEPs (probably the striate cortex). The motion pathway, presumably deriving mainly from the magnocellular layers of the lateral geniculate nucleus, may be relatively spared in amblyopia.

Adolescent↗
PubMed1996

Randomized study of vinorelbine (VRB) versus vindesine (VDS) in previously untreated stage IIIB or IV non-small-cell lung cancer (NSCLC). The Japan Vinorelbine Lung Cancer Cooperative Study Group.

PURPOSE: We compared the activity of vinorelbine (VRB) and vindesine (VDS) in a randomized crossover study in patients with previously untreated stages IIIB or IV non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Two hundred four patients were assessable for response and toxicity. VRB was administered at a dose of 25 mg/m2 weekly and VDS at a dose of 3 mg/m2 weekly. Patients who failed to respond after 4 cycles of initial monotherapy were switched to a combination chemotherapy (VRB-->VDS + cisplatin (P) or VDS-->VRB + P). RESULTS: Objective response was observed in 31.1% of patients in the VRB arm versus 8.9% of those in the VDS arm (P = 0.0002). The median duration of response to VRB was 18.5+ weeks (range, 7.9 to 107.5+ weeks) compared with 11.7+ weeks (range, 6.0 to 35.0+ weeks) for VDS. Of the 69 patients who failed to respond to initial monotherapy, 33 in the VRB group who subsequently received VDS + P did not respond and 13 (26.5%) of 49 initially on VDS who received subsequent VRB + P responded. The rates of grades 3 and 4 leukopenia were similar in the two monotherapy arms (VRB, 55.3% vs. VDS, 48.5%). However, grade 3 anemia was more frequent in the patients on VRB than in those on VDS. The incidence of peripheral neurotoxicity was significantly higher with VDS than with VRB (P = 0.002), but VRB induced a slightly higher rate of local cutaneous reaction than VDS (P = 0.012). With the combination of cisplatin and these vinca alkaloids, peripheral neurotoxicity was less frequent in the VRB group than in the VDS group. CONCLUSION: Our results demonstrate that VRB yields a higher response rate than VDS in stage IIIB or IV NSCLC, with the same extent of toxicity in terms of leukocytopenia. The peripheral neurotoxic effects were also milder with VRB than with VDS. In second-line chemotherapy, there was a notable difference in response between the VRB + P and VDS + P regimens.

Adult↗
PubMed1996

[Clinical evaluation on causes of death in patients with active pulmonary tuberculosis].

Seventy one patients with active pulmonary tuberculosis who died during the past 5 years (1989 to 1993) were evaluated on their causes of death. Twenty two patients (31%) died directly of tuberculosis, and among them, 18 patients (81%) of 22 patients who died of tuberculosis) had very advanced tuberculosis. The majority of them (64%) were old age over 70 years and were bedridden due mostly to cerebrovascular injuries. The serum level of albumin was low in all 17 patients in whom it was measured. Establishment of diagnosis of tuberculosis was delayed over one month after the onset of symptoms in 59% of patients who died of severe disease. Sixty one percent (11/18) of patients died within the first month after the initiation of chemotherapy and about 90% (16/18) died within 3 months. Two patients died from massive hemoptysis and other patients died of either respiratory failure or tuberculosis meningitis. From these observations it was found that very advanced tuberculosis was the major cause of death in patients who died of tuberculosis and that the advanced disease was chiefly caused by the delay on the establishment of diagnosis, and it was most important to detect tuberculosis as early as possible, with regular check up of chest X-ray and frequent examination for AFB (acid-fast bacilli) for tuberculosis suspected patients. On the other hand, the majority of patients (49/71) died of complicating medical problem unrelated to tuberculosis. Seventeen patients died from malignancy (seven lung cancer, four lymphoma, two laryngeal cancer, etc). Ten deaths were the result of bacterial superinfection. Other patients died from respiratory failure due to COPD, arteiosclerotic heart disease, or cerebrovascular injuries, etc. Two patients of old age died of hepatic failure possibly caused by adverse reaction of TB chemotherapy. It was found that diseases unrelated to tuberculosis were the cause of death in approximately 70% of patients with active tuberculosis, and it should be emphasized to detect early and to treat these diseases, in particular malignancy. And it is also imperative that the chemotherapy for TB must be instituted very carefully with frequent monitoring of liver function in patients with old age.

Adult↗
PubMed1996

Visual evoked potential evidence for magnocellular system deficit in dyslexia.

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.

Child↗
PubMed1996

Advanced electrophysiological diagnostics of hepatic and portosystemic encephalopathy.

In 28 patients with liver cirrhosis, pre- and post-TIPS (transjugular intrahepatic porta-caval shunt), pattern-reversal visual evoked potentials (PREPs) and motion-onset visual evoked potentials (M-VEPs) examinations, EEG spectral analysis and Number Connection Test were performed. The M-VEPs (representing an activity of the magnocellular system of the visual pathway and reactions of the mediotemporal associate visual area) displayed the highest sensitivity (latencies delay) for detection of subclinical hepatic encephalopathy. The PREPs (originating in the primary visual cortex -area striata) were not significantly changed in comparison with a group of age matched controls. The EEG frequency spectrum exhibited significant slowing of the dominant frequency which was more pronounced in the post-TIPS examination. Combined analysis of the M-VEPs latency and EEG dominant frequency seem to be a recommendable method for early detection and objective classification of subclinical hepatic or portosystemic encephalopathy.

Adolescent↗
PubMed1996

Video-signal synchronizes registration of visual evoked responses.

Autodesk Animator software offers the suitable technique for visual stimulation in the registration of visual evoked responses (VERs). However, it is not possible to generate pulses that are synchronous with the animated sequences on any output port of the computer. These pulses are necessary for the synchronization of the computer that makes the registration of the VERs. The principle of the circuit is presented that is able to provide the synchronization of the analyzer with the stimulation computer using Autodesk Animator software.

Computer Graphics↗
PubMed1995

Simultaneously recorded retinal and cerebral potentials to windmill stimulation.

Visual evoked retinal and cerebral potentials were recorded to onset rotation of an isoluminant sectored disc. While the retinal potentials recorded to onset rotation closely resembled the electroretinogram to a checkerboard or stripe pattern of fixed element size, the visual evoked potential changed interindividually and intraindividually from a fast positive wave at high contrasts, velocities and number of windmill segments to a later negative component at low contrasts, velocities and windmill segments. With change in luminance, contrast, speed and extent of rotation field size and number of disc segments, the visual evoked potential was generally less affected than the electroretinogram.

Adolescent↗
PubMed1995

Contrast dependence of motion-onset and pattern-reversal evoked potentials.

This study deals with the effect of stimulus contrast, between 1.3% and 96%, on the visual evoked potentials (VEPs) for onset of motion and for pattern reversal of checkerboard stimuli. The VEPs for pattern reversal and for the onset of motion both contain an initial positive peak (P1; peak latency about 120 msec) followed by a later negative peak (N2; peak latency 160-200 msec). However the P1 peak dominates the pattern-reversal VEP when recorded from the midline occipital lead, where it is maximal, while the N2 peak is larger in the motion-onset VEP, especially when recorded from unipolar lateral occipital leads. Whereas the amplitude of the P1 peak in both the pattern-reversal VEP and the motion-onset VEP decreases with decreasing contrast (becoming undetectable at a contrast of about 2% for the motion-onset VEP), the amplitude of the N2 peak in both types of VEP does not vary significantly with contrast, above a contrast of 1.3%. The increase in peak latency with decreasing contrast is also more pronounced for the positive than the negative peaks of both types of VEP. Taking into account the high contrast sensitivity of the magnocellular system (thought to be involved in the processing of motion) compared with the parvocellular system (probably more concerned with the processing of form), our findings suggest that for both motion-onset and pattern-reversal VEPs the negative peak is attributable to the motion-processing magnocellular pathway and the positive peak to the form-processing parvocellular system.

Adult↗
PubMed1995

Motion-onset VEPs improve the diagnostics of multiple sclerosis and optic neuritis.

In addition to standard pattern-reversal VEPs, the motion-onset VEPs were examined in 50 patients with acute unilateral retrobulbar neuritis (RN) and in 187 patients with possible or definite multiple sclerosis (MS). In MS patients (without sign or history of RN), the results of both types of VEPs correlated only partially. 26.2% of them displayed changes only in the motion-onset VEPs having the pattern-reversal VEPs completely normal. That is why we suppose that the magnocellular system (tested by motion-onset VEPs) can be affected by demyelination separately. In 28 patients with "pure" RN (without any other sign indicating demyelination disease) the always abnormal pattern-reversal VEPs were accompanied by delayed motion-onset VEPs in only 28.6% of patients. In contrast, much higher rate--68.2%--of delayed motion-onset VEPs was found in the 22 RN patients simultaneously suspected of MS These results indicate that RN affects predominantly the parvocellular visual system (tested by reversal VEPs). Distinct latency changes of the motion-onset VEP's in RN patients seem to signal a linkage between RN and demyelination.

Evoked Potentials, Visual↗
PubMed1994

N omega-phosphoarginine phosphatase from rat renal microsome was alkaline phosphatase.

Activity hydrolyzing both N omega-phosphoarginine and glucose-6-phosphate was detected in rat renal microsome but not in hepatic microsome. Renal microsome was solubilized with 1% n-octyl-beta-D-thioglucoside and purified with DEAE-Sepharose column chromatography. Fractions hydrolyzing both N omega-phosphoarginine or glucose-6-phosphate were subjected to 7.5%-polyacrylamide gel electrophoresis in the presence of 0.1% sodium dodecyl sulfate. Phosphatase activity in the gels was detected by a lead nitrate stain using N omega-phosphoarginine or glucose-6-phosphate as substrates. Both substrates produced a stain in the region of the gel corresponding to a protein with a mass of 150 kDa. Extracts of slices from this region of the gel also hydrolyzed phosphocreatine, inorganic pyrophosphate, and O-phosphotyrosine. Moreover, the phosphatase had its optimal pH in the alkaline range and was inhibited completely by 20 microM sodium vanadate, 1 mM cysteine, and 1 mM tetramisole. All these properties indicate that the microsomal phosphoamidase (EC 3.9.1.1) of rat kidney was identical with alkaline phosphatase (EC 3.1.3.1).

Alkaline Phosphatase↗
PubMed1994

Nucleoside monophosphoramidate hydrolase from rat liver: purification and characterization.

1. Adenosine 5'-phosphoramidate hydrolase of 29 kDa was isolated from rat liver cytosol. 2. It consisted of two subunits of 14 kDa. 3. It hydrolyzed nucleoside 5'-monophosphoramidates into nucleoside 5'-monophosphates and ammonia, while it did not hydrolyze adenylyl phosphoramidate, adenylyl imidodiphosphate and N-phosphorylated compounds like phosphocreatine, N omega-phosphoarginine, 6-phospholysine and 3-phosphohistidine. 4. Divalent cations and cyclic AMP had no effect on the hydrolytic activity.

Animals↗
PubMed1994

3-Phosphohistidine/6-phospholysine phosphatase from rat brain as acid phosphatase.

A phosphatase hydrolyzing 3-phosphohistidine and 6-phospholysine was purified from rat brain cytosol to 90% homogeneity on polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. One milligram of protein of the purified phosphatase released inorganic phosphate from 3-phosphohistidine, 6-phospholysine, AMP, GMP, and p-nitrophenyl phosphate at velocities of 6.5, 15.6, 15.0, 6.9, and 8.3 mumol/min, respectively. However, the purified enzyme could not hydrolyze N omega-phosphoarginine and phosphocreatine, which are substrates for phosphoamidase [EC 3.9.1.1]. The molecular masses of the holoenzyme and the subunit were 94 and 50 kDa, respectively, and the sedimentation coefficient of the native enzyme was 6.3 s, indicating that it was a dimeric enzyme of identical subunits. The enzyme functioned well under acidic conditions, and 50% of the activity was inhibited by 30 microM tartrate, 4 microM vanadate, 20 microM molybdate, 4 microM VCl3, or 13 microM MoCl5. These results indicate that the present hydrolase belongs to the acid phosphatase group [EC 3.1.3.2].

Acid Phosphatase↗
PubMed1994

[Sensory and electrical responses in stimulation of the macula with short-wave (407-527 nm) linear polarized light (Haidinger polarization brushes)].

We investigated Haidinger's (1844) entoptic polarization brushes of the macula psychophysically and electrophysiologically during rotation of plane-polarized blue (< 520 nm) light projected to a polarization screen. Psychophysically the sensitivity of the brushes was highest between 470 and 490 nm, with a steep decrease at longer wavelengths. Increase of adaptive illumination (I) above 0.1 cd/m2 increased the increment threshold (delta I) of the brushes between 407 and 515 nm about equally (delta I/I = 0.9). Comparison of the action spectrum of different photoreceptors with the spectral sensitivity of Haidinger's brushes suggested synergistic contributions of blue, green and red photoreceptors. A decrease in visual acuity to 0.01 by plus lenses did not affect the light threshold of the brushes significantly, while blurring by Bangerter foils increased the threshold markedly (about eightfold at visual acuity of 0.01). Thus, the determination of threshold of Haidinger's brushes provides the means of investigating certain macular functions behind, and widely independent of, opacities of the ocular media. While no retinal potentials (ERG) were seen during rotation of the polarizer, we obtained cortical potentials (VEP) closely related to the appearance of Haidinger's brushes in response to rotation onset of blue polarized light. The potential derived from Oz+Ol+Or consisted of a phasic negative response after a peak latency of 295 +/- 34 ms (N 295). Similar responses were also obtained to medium and long wavelengths (extrinsic windmill rotation during foveal fixation at stimulus conditions closely related to Haidinger's brushes: 3 degrees field, 2 cy/rev, 2 cd/m2, contrast 0.15). Thus VEP recording permits the comparison of entoptic and extrinsic excitation of the macula.

Adult↗
PubMed1994

[Biochemical analysis in dogs of the beagle breed. 2. The content of Na, K, Ca, Mg, total P, Fe, Cu and Zn in tissue of fetuses and dogs of different ages].

In dog fetuses in the age of 45 and 55 days as well as in dogs in the age of one day, of 28 days, of 6 and of 18 months the content of minerals (Na, K, Ca, Mg, total-P), of Fe, of Cu and of Zn in different tissues (cerebrum, cerebellum, brain stem, lung, heart respectively left and right ventricle, liver, spleen, kidney respectively cortex and medulla, pancreas, M. biceps femoris and M. longissimus dorsi) was analysed. During the prenatal and postnatal development there are changes in the content of the mentioned elements in many tissues, that are necessary for the specialisation for certain functions.

Aging↗