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Biomedical subjects

M Kunimoto

Publications and source records attributed to M Kunimoto.

125 records · Page 7Linked to original sources
PubMed1984

Effects of nitrogen dioxide on red blood cells of rats: alterations of cell membrane components and populational changes of red blood cells during in vivo exposure to NO2.

Male Wistar rats were exposed to 4 ppm NO2 for 10 days in order to examine the relationship between the changes in components of red cell membranes and alterations of erythrocyte population. Na+, K+-ATPase activity of red blood cell membranes of exposed animals showed a significantly higher value than that of the control at the first and fourth days of exposure and then decreased to under the control value at the seventh day. In order to examine changes in erythrocyte population, red blood cells were fractionated into four fractions according to their density using Dextran density centrifugation. The alteration of the percentage of lowest-density cells (fraction IV) of exposed animals was completely consistent with that of Na+,K+-ATPase activity in addition to that of the sialic acid content as described in a previous report (K. Kaya, T. Miura, and K. Kubota (1980). Environ. Res. 23, 397-409.). The percentage of fraction IV was 1.43- (P less than 0.05) and 1.68-fold (P less than 0.01) those of the control at the first and fourth days of exposure, respectively, and then decreased to under the control value at the seventh day. This decrease accompanied increases in the percentages of higher-density cells (fractions I and II). Examination of subfractions of red blood cells showed that Na+,K+-ATPase activity and the sialic acid content of three fractions with lower densities have higher values in exposed animals than in the control 1 day after exposure to NO2. Based on these results, it is concluded that increases in Na+,K+-ATPase activity and the sialic acid content occurring 1 day after exposure to 4 ppm NO2 were caused by elevated levels of these components in three fractions with lower densities as well as by an increase in the percentage of lowest-density cells in the erythrocyte population. It was also suggested that NO2 inhalation accelerated aging of erythrocytes with respect to density. The change in Ca2+,Mg2+-ATPase activity, in addition to that in the hexose content as described in a previous report (Kaya et al., 1980), was different from those in the sialic acid content and Na+,K+-ATPase activity. Ca2+,Mg2+-ATPase activity and the hexose content of exposed animals showed slightly reduced values 1 day after exposure to NO2. In all subfractions of red blood cells these values were slightly lower in exposed animals than in the controls. Therefore, reduction in Ca2+,Mg2+-ATPase activity and the hexose content is not due to changes in erythrocyte population.

Animals↗
PubMed1983

[Study on the serum concentrations of gentamicin after intravenous drip infusion].

Serum concentrations of gentamicin (GM) were monitored after intravenous drip infusion of 60 mg over 30 minutes, 1 hour and 2 hours. These concentrations were compared with those after intramuscular injection. The mean peak serum concentration obtained at 30 minutes after intramuscular injection (5.09 micrograms/ml) and those obtained at the end of intravenous drip infusion (5.17--6.66 micrograms/ml) were comparable. Serum concentrations decreased to less than 2.0 micrograms/ml at 6 to 8 hours after injection or infusion in all cases except 1 with less body weight than others. Pharmacokinetic analysis showed that the T1/2 of GM ranged from 2.49 to 4.33 hours and that the AUC ranged from 19.66 to 27.09 hr X micrograms/ml. Results obtained in this study suggested that the usefulness of intravenous drip infusion over the time from 30 minutes to 2 hours is equal to that of intramuscular injection in the GM therapy.

Adult↗
PubMedDate not supplied

Posterior cervical N13 in median nerve SEP has two components.

Somatosensory evoked potentials (SEPs) to median nerve stimulation were investigated in normal controls and patients with cervical lesions. Attention was paid primarily to the N13 and P13 components in the posterior and anterior cervical records with non-cephalic references. In normal subjects the CV2 and CV6 electrodes registered N13 with almost the same amplitude. Dissociation between N13 at the CV2 electrode (ucN13) and N13 at the CV6 electrode (lcN13) was observed in the patients. In 4 patients with cervical dorsal column lesions, lcN13 was preserved but ucN13 was almost completely absent. Anterior cervical P13 (acP13) was preserved. In a patient with syringomyelia, lcN13 and acP13 were greatly attenuated while ucN13 was relatively well preserved. These results suggested that the origins of ucN13 and lcN13 are different. The generator of lcN13-acP13 was assumed to be the postsynaptic potential of the dorsal horn interneurons. Upon comparison with previous animal studies and intraoperative studies, it was concluded that the generator of ucN13 is the postsynaptic potential of the cuneate nucleus.

Adult↗
PubMedDate not supplied

Relationships between benzodiazepine receptors, impairment of GABAergic transmission and convulsant activity of beta-CCM: a PET study in the baboon Papio papio.

Central type benzodiazepine receptors were studied in vivo by positron emission tomography in brain areas of 2 different groups of the baboon Papio papio: non-photosensitive (group 1) and those with an allylglycine-induced decrease in GABA-mediated inhibition (group 2). Further, a naturally photosensitive Papio papio (+3 level of photosensitive response) was compared to both groups. Regional brain binding of the specific benzodiazepine receptor ligand, [11C]Ro 15-1788, was not significantly different between groups 1 and 2. In addition, the data from the naturally photosensitive Papio papio did not seem to differ markedly from groups 1 and 2 either. Pharmacological effects of increasing doses of beta-CCM (0.05-3 mg/kg i.v.) and regional benzodiazepine receptor occupancy by the drug were simultaneously studied using electroencephalographic activity recording and positron emission tomography. A positive correlation was observed between the degree of photosensitivity of the baboon and sensitivity to the action of beta-CCM, with increasing convulsant efficacy of beta-CCM in going from group 1 to the naturally photosensitive baboon, then to group 2. Dose-related displacement curves of [11C]Ro 15-1788 binding by beta-CCM revealed that reduction in brain GABA concentration did not modify the inhibitory potency of beta-CCM on [11C]Ro 15-1788 binding in cerebral cortex. This suggests a lack of detectable in vivo allosteric effects of GABA on beta-CCM binding during beta-CCM-induced seizures. Thus, a given dose of beta-CCM displayed increasing pharmacological potency in going from baboons with the lowest photosensitivity to those with the highest, whereas benzodiazepine receptor occupancy by beta-CCM was similar in the cerebral cortex of the different baboons. Conversely, a given level of convulsant activity of beta-CCM was related to a different benzodiazepine receptor occupancy by the drug, depending on the photosensitivity of Papio papio. A given dose of a drug may, thus, have a different pharmacological potency when occupying the same number of receptors, depending on the physiopathological state of the subject.

Animals↗
PubMedDate not supplied

Effect of macular and peripheral retina coagulation on photosensitive epilepsy in the forebrain bisected baboon, Papio papio.

The effects of macular and peripheral retina coagulation were examined in photosensitive baboons, Papio papio (PP), with or without forebrain bisection. The temporal part of the macula and surrounding retina of the left eye were coagulated with an Argon laser and later confirmed histologically. In forebrain nonbisected baboons, intermittent light stimulation of the operated eye produced bisymmetrical and bisynchronous spikes and waves and self-sustained seizures. In forebrain-bisected baboons intermittent light stimulation of the operated eye produced spikes and waves and self-sustained seizures localized to the contralateral hemisphere. Subsequent stimulation of the nonoperated eye in the same animal produced spikes and waves and seizures either bilaterally or only in the opposite hemisphere when stimulation took place during the postictal silent period in the first hemisphere. In both cases, the tonic phase of the seizure was always bilateral but asymmetrical as shown by electromyographic recordings. Based on these data, it has been hypothesized that the tonic phase is mediated, in part, through crossed interreticular pathways, by one or both cerebral hemispheres. However, data are also compatible with a possible origin of the tonic phase of the seizure being partly localized in the medial frontal cortex. Results demonstrated (1) the usefulness of laser coagulation of the temporal portion of the macula and retina for the study of the functional independence between two cerebral hemispheres, (2) the critical role of the corpus callosum (CC) in bisynchronization and generalization of the intermittent light stimulation (ILS)-induced seizure, (3) independent excitability of each cerebral hemisphere by the ILS, and (4) the critical role of cortical visual afferents for inducing epileptic phenomena in this species.

Animals↗
PubMedDate not supplied

Electroencephalographic study of the GABA-withdrawal syndrome in rats.

The spatial and temporal EEG features of the epileptogenic syndrome induced by cessation of chronic intracortical GABA infusion in normal rats are described. In the initial stages, the paroxysmal discharges (PDs) induced by withdrawal from unilateral GABA application may appear either unilaterally or bilaterally, although with greater amplitude on the infused side. PDs are transitorily accompanied by behavioral signs of distal myoclonus of the body territory corresponding to the infused area (contralateral hindlimb). Later, the paroxysmal activity becomes more localized, circumscribed to the cannula-infused site and with ipsilateral propagation to anterior cortical areas. The amplitude of PDs decreases progressively while their frequency increases, reaching its maximal value at about 4 h after the first PDs have appeared. In the final stages of the syndrome, which may last several days, clinical manifestations are absent and PDs are activated by slow-wave sleep and reduced during REM sleep and waking. Chronic intracortical applications of taurine failed to induce any electroclinical changes on withdrawal and were unable to inhibit the focus elicited by GABA withdrawal, whereas reinstatement of GABA infusion into the epileptogenic area was effective in blocking the paroxysmal activity. Intracortical infusion of baclofen induced the appearance of an epileptogenic focus that waned on withdrawal. The GABA-withdrawal syndrome appears to be a new model of focal status epilepticus; it may be useful as an experimental model of human partial epilepsy to investigate the role of GABAergic neurotransmission.

Animals↗
PubMedDate not supplied

[A case of Foix-Chavany-Marie syndrome and crossed aphasia after right corona radiata infarction with history of left hemispheric infarction].

Foix-Chavany-Marie syndrome (FCMS) is a syndrome that presents facio-pharyngo-glosso-masticatory diplegia with automatic voluntary dissociation. Its most common etiology is stroke in the regions of bilateral opercula. We described a 75-year-old woman with FCMS and crossed aphasia. She had cerebral infarction of left middle cerebral artery territory 23 years before. At that time she had transient right hemiparesis, but no aphasia. This time, she suddenly became mute and was brought to our hospital. Neurological examination revealed severe weakness in her bilateral lower face, pharynx, tongue, and sternocleidomastoideus. She had no weakness of limbs. Her listening comprehension was moderately disturbed and handwriting was paragraphic. Her emotional facial movement was maintained despite of disturbed volitional facial movement. CT scan disclosed fresh infarction at the right corona radiata and old infarction at the left middle cerebral artery territory. In this patient, lesions at the left operculum and right corona radiata with the preserved right operculum gave rise to FCMS. This implies following possibilities: 1) the corticobulbar tract and corticospinal tract run separately at the corona radiata, 2) volitional and emotional tracts of facial movement run separately at the corona radiata. It was demonstrated that FCMS is not always caused by bilateral operculum lesions. Our patient did not show aphasia after the first stroke including left language area, but became severely aphasic after the right corona radiata infarction. Simultaneous occurrence of FCMS and aphasia after corona radiata lesion suggested that the corticobulbar tract and a tract that conducts linguistic information are running adjacently in the corona radiata. Our case suggested that restricted corona radiata lesion may cause severe subcortical aphasia and in case of additional contralateral corticobulbar tract lesion, severe dysarthria may occur.

Aged↗
PubMedDate not supplied

Relationship between the fecal occult blood test and benign anal disorders.

BACKGROUND/AIMS: The fecal occult blood test is a very useful method for mass screening for colorectal cancer. The possibility of the fecal occult blood test being positive is high even in benign anal disorders, but the relationship between anal disorders and the fecal occult blood test has not been fully studied. METHODOLOGY: During the period from November 1995 to April 1996, we performed both fecal occult blood test and sigmoid colonofiberscopy for 440 patients with anal disorders who visited our hospital for the first time. RESULTS: The positive fecal occult blood test rate was 18.8% (77/409) for those who had only anal disorders and no findings in the colon and rectum. The positive fecal occult blood test rate was significantly high in the cases with polyps (42.3%) and in those with colorectal cancer (60%). CONCLUSIONS: These findings suggested the need to analyze fecal occult blood test, keeping in mind that fecal occult blood test might be positive even without any malignant findings in the large intestine in about 20% of cases of patients have anal disorders when fecal occult blood test is performed.

Anus Diseases↗
PubMedDate not supplied

N-isopropyl I-123 p-iodoamphetamine brain scans with single photon emission computed tomography: mental sweating and EEG abnormality.

We studied a patient with hyperhidrosis and electroencephalographic (EEG) abnormality using N-isopropyl I-123 p-iodoamphetamine (I-123 IMP) with single photon emission computed tomography (SPECT). EEG abnormality was found predominantly in the frontal area, and sharp wave bursts were induced by hyperventilation. Ictal and nonictal scans were obtained with simultaneous EEG recordings. Ictal scans revealed increased uptake of IMP in the frontal cortex, reflecting hyperperfusion to the frontal area. The ratio of IMP uptake of the frontal to the parietal cortex (F/P ratio) was calculated both in the ictal and nonictal phase. In the ictal phase, the F/P ratio was 1.23, compared with 0.91 in the nonictal phase. The data indicated altered regional cerebral blood flow with EEG abnormality and hyperventilation load. Although the relationship between sweating and cortical function is not fully understood, our study indicates that excessive mental sweating is related to frontal cortical dysfunction. I-123 IMP-SPECT seems valuable for topographical demonstration of epileptogenic lesions and understanding the pathophysiological process of mental sweating.

Adult↗
PubMedDate not supplied

The relation between irregular bowel movement and the lifestyle of working women.

BACKGROUND/AIMS: It is said that constipation is related to the occurrence and increase of bowel disease and colon cancer; however, there are few reports on this subject, and information about bowel movements in connection with the lifestyles of working women are almost non-existent. METHODOLOGY: We conducted a survey of working women and obtained 509 valid responses. The odds ratios of the following factors were calculated: the number of bowel movements, skipping breakfast, dieting, suppressing bowel movements, haemorrhoids (anal fistulae), and stress. RESULTS: The prevention of skipping breakfast and suppressing bowel movement had a big effect on the increase of bowel movements and in preventing constipation, especially when the two factors were combined. For those experiencing haemorrhoids, stress had a great influence. More than half of the respondents admitted that the first appearance of the signs of constipation was during their high school days or before. The peculiar sense of shame of women in their adolescence, the disorder of daily life, the desire to obtain a slim figure and stress are thought to be triggers for the problem of constipation. CONCLUSIONS: It is clear that the four factors in daily life defined above can have significant influence on constipation in women. It is thought that a proper diet with the right guidance, as well as social considerations can have favourable effects on these factors.

Adolescent↗