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Biomedical subjects

S Niwa

Publications and source records attributed to S Niwa.

At least 127 records · Page 7Linked to original sources
PubMed1990

Psychiatric patients showing irregular beta activities in EEGs and treatment with antiepileptic drugs: a report of 15 cases.

Fifteen psychiatric cases are reported who were clinically diagnosed as schizophrenic, affective disorders, or neurotic, but resisted standard medication regimens, all showing irregular beta activities on EEGs. The cases tended to display symptoms in common, such as dysphoria, emotional instability or frequent physical complaints. These characteristic symptoms share something mutually with the symptoms shown in some epileptic patients or psychiatric patients with epileptic EEG abnormalities without clinical seizures. Antiepileptic drugs seemed more specifically effective to the above symptoms. More than half of these cases showed improvement on EEG findings such as a decrease in irregular beta activities and an increase in rhythmicity or regularity of alpha activities along with clinical improvement with the administration of adjunctive antiepileptic drugs. These results suggest that the adjunctive administration of antiepileptic drugs to patients with irregular beta activities on EEGs is clinically useful and an EEG examination has much value in psychiatric practice to find the criteria of drug therapy.

Adult↗
PubMed1990

[Effects of maternal exercise using bicycle ergometer on maternal heart rate, blood pressure, oxygen consumption and fetal heart rate].

The effects of maternal exercise on pregnant women and fetal well-being are largely unknown. Forty-eight pregnant women between 16 and 39 weeks' gestation were exercised on a bicycle ergometer. We studied the oxygen consumption, blood pressure, maternal and fetal heart rate (FHR) at rest, during and after the exercise. The mean maternal heart rate and blood pressure were increased to 166.1 +/- 12.2/min (mean +/- S.D., n = 48) and 161.1 +/- 20.1/82.7 +/- 15.2 mmHg, respectively, at maximal exercise. The absolute oxygen consumption (1/min) was increased with advancing pregnancy at rest and maximal exercise, but the functional oxygen consumption (ml/kg/min) was not changed during pregnancy. The mean FHR was increased about 4 and 9 bpm in the 2nd and 3rd trimesters, respectively. Abnormal FHR patterns after the exercise were observed in 8 cases (16.7%), mild tachycardia: 6 cases, deceleration: 2 cases. Increasing the maternal heart rate at maximal exercise, increased the frequency of the abnormal FHR pattern. When the maternal heart rate was below 160/min, there was no abnormal FHR pattern. These results suggest that several medical checks should be done not only for the mother but also for her fetus during exercise and the maternal heart rate should not exceed 160/min.

Blood Pressure↗
PubMed1989

Non-traumatic dissecting aneurysms of the intracranial vertebral artery. Report of six cases.

We present 6 cases with dissecting aneurysm of the intracranial vertebral artery who developed subarachnoid haemorrhage (SAH). The following procedures were performed in this series; trapping of the involved artery in 2, proximal occlusion of the vertebral artery with detachable balloon in 2, and proximal clipping of the vertebral artery in 2. Proximal occlusion of the vertebral artery in 4 and trapping of the vertebral artery in one gave excellent results. We believe the treatment of choice is proximal occlusion of the vertebral artery, either by open surgery or by interventional neuroradiological procedures.

Adult↗
PubMed1989

Psychological intervention can partly alter P300-amplitude abnormalities in schizophrenics.

In the present study, we investigated whether psychological interventions can alter P300-abnormalities, specifically enhancing reduced P300-amplitudes, in schizophrenics. A three-tone discrimination task was employed for recording P300s, in which psychological intervention to facilitate target detection was performed through delivering a buzzer sound one second after each designated target tone that informed its occurrence. This procedure was done exclusively during the third and fourth sessions among the six sessions in total. When the data for all the patients were analyzed as a whole, no significant change was observed. However, when the patients were broken down into two groups based on the P300-amplitudes in the first and second sessions, significant effects of the intervention emerged. The group with smaller P300-amplitudes showed a significant increase in P300-amplitudes as well as improved performance levels during and after the intervention sessions. On the contrary, the group with larger P300-amplitudes displayed a significant decrease in P300-amplitudes in these sessions. Interestingly, the above results were consistent with the subjective difficulty changes experienced by the patients through the sessions. Overall, the above results indicate that psychological interventions can partly enhance reduced P300-amplitudes in schizophrenics.

Adult↗
PubMed1988

Efficacy and tolerance of tiaprofenic acid during long term administration to rheumatoid arthritis patients.

In a multicentre trial, tiaprofenic acid was administered in a dosage of 600 mg/day for 12 months to 109 patients with rheumatoid arthritis. The results in 79 patients, who did not receive any other non-steroidal anti-inflammatory drugs concomitantly, were assessed. Of the 79 patients, 11 withdrew from the study within one year. The reasons for withdrawal were personal reasons in 4 cases, side effects or abnormal laboratory values in 2, no change or aggravation of symptoms in 2, improvement of symptoms in 2, and identification of systemic lupus erythematosus in one. Overall improvement was definite in 27 patients (34.2%) and slight in 21 patients (26.6%). Overall usefulness was definite in 30 patients (38%) and slight in 27 patients (34.2%). The duration of morning stiffness, joint index and Lansbury activity index showed significant improvement after 6 months' administration. Side effects were observed in 2 cases (2.5%) and abnormal laboratory results were seen in 3 (3.8%). These disappeared on either continuation or discontinuation of treatment.

Adult↗
PubMed1988

Decompression of the vertebral artery for bow-hunter's stroke. Case report.

A case of cerebellar infarction induced by repeated neck rotation ("bow-hunter's stroke") is reported. The most likely mechanism is that repeated rotational neck movement brings about thickening of the atlanto-occipital membrane, fixing the vertebral artery in the vascular groove of the atlas. The vertebral artery is thus pinched at the time of neck rotation, leading to thrombus formation. Embolization results in cerebellar infarction. Surgical decompression of the vertebral artery at the level of the atlas in this case relieved the symptoms, and postoperative angiography demonstrated good flow within the vertebral artery even when the neck was rotated. It was not necessary to restrict the patient's neck movement postoperatively.

Adult↗
PubMed1984

Correlations of event-related potentials with schizophrenic deficits in information processing and hemispheric dysfunction.

In order to obtain further insight into hemispheric dysfunction in schizophrenics, two experiments were conducted employing event-related potential (ERP) recording during dichotic detection tasks as well as syllable discrimination tasks. Results concerning ERPs derived from the T3 and T4 regions are reported. Based on results in the two experiments, it is concluded that schizophrenics display a dysfunction of the left hemisphere, as well as a dysfunction in the ingration mechanism of both hemispheres. It is also speculated that the left-hemisphere dysfunction in schizophrenics is particularly correlated with positive psychotic symptoms.

Adult↗
PubMed1984

Verbal memory disturbances in left temporal lobe epileptics.

The relationship between laterality of paroxysmal discharges and characteristics of disturbances in memory functioning was investigated in temporal lobe epileptics. Subjects consisted of 22 temporal lobe epileptic patients, in whom the foci of the paroxysmal discharges were localized to one side of the temporal regions. The left focus group consisted of 10 patients; the right focus group, 12. Subjects were required to recognize verbal material presented to one hemisphere by means of a tachistoscope. The left focus group alone failed to demonstrate a right visual field superiority in these tasks. It was concluded that the left focus group specifically demonstrate disturbances in verbal memory functioning, particularly when stimuli were presented to the left hemisphere. Paroxysmal discharges seemed to interfere with normal memory functioning in the region where the foci of these discharges were found.

Adult↗
PubMed1984

Hand and eye preference patterns in elementary and junior high school students.

There has been some controversy concerning the relationship between eye preference and hand preference. Another controversy involves age differences in eye preference patterns. These two issues were investigated in 725 elementary and junior high school students employing various tests. It was found that a sex difference exists in hand preference patterns. Males seem to display less right hand preference as compared to females; on the contrary, these was no sex difference in eye preference patterns. Hand preference was found to be negligibly correlated with eye preference. The distribution patterns of eye preference were reversed between right handers and left handers. Age difference were not observed in eye preference patterns.

Adolescent↗
PubMed1984

Electron transfer reactions of chemically modified plastocyanin with P700 and cytochrome f. Importance of local charges.

Chemically modified spinach plastocyanin, in which negatively charged carboxyl residues are replaced with positively charged amino residues, has been prepared. Four distinct species of chemically modified plastocyanin, having 1 to 4 mol of modified carboxyl residue per mol of plastocyanin, could be separated by ion-exchange chromatography on DEAE-Sephacel. The rate of electron transfer from reduced cytochrome f to oxidized singly substituted plastocyanin was 30% of that of the native unmodified plastocyanin, and the reaction rate decreased further with increasing number of modified carboxyl residues. These results indicate the importance of electrostatic interactions between the negative charges on plastocyanin and the positive charges on cytochrome f in this reaction. Since the overall net charge of cytochrome f is negative at neutral pH, the positive charges on cytochrome f involved in the reaction should be localized ones. On the other hand, the rates of electron transfer from reduced singly and doubly substituted plastocyanin to photooxidized P700 in the P700-chlorophyll alpha protein complex were similar to that of native plastocyanin, which suggests that these carboxyl residues have only a minor role in the electron transfer to P700. Although divalent cation is essential for the electron transfer from native plastocyanin to P700 at neutral pH, the triply substituted plastocyanin could donate electrons to P700 even without MgCl2, and the rate of this reaction reached the maximum at a low concentration of MgCl2 (less than 2.5 mM). The modification of four carboxyl residues per plastocyanin molecule activated this reaction to the maximum level without MgCl2.(ABSTRACT TRUNCATED AT 250 WORDS)

Chlorophyll↗
PubMed1984

Assessment of P300 latencies for individual EEG responses employing an adaptive correlating filter.

Correlations between latencies of P300 components in evoked potentials and reaction times were investigated in two normal subjects. The subjects were required to perform choice reaction tasks, responding to particular tones among three tones with different frequencies. EEGs were recorded at the Pz region monopolarly. Latencies of P300 for individual EEG responses were measured employing an adaptive correlating filter. Cross-correlation coefficients between the second templates employed to identify P300s and individual responses for the subjects ranged from 0.623 to 0.997, with the mean value being 0.931. The correlation coefficient between latencies of P300 and reaction times for the subjects was 0.659. Thus, the adaptive correlating filter was proved to be useful in psychophysiological studies.

Adult↗