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Biomedical subjects

M Kurachi

Publications and source records attributed to M Kurachi.

At least 109 records · Page 6Linked to original sources

Changes in amitriptyline distribution in rat brain during a 14-day continuous infusion.

The amitriptyline (ATL) distribution in 12 rat brain regions was examined during 2-, 7- and 14-day continuous ATL infusion, starting with 18 mg/kg/day on the first day. The concentration of nortriptyline, a demethylated metabolite of ATL, in brain and serum was very low in comparison with ATL. The brain/serum concentration ratio of ATL and absolute ATL concentration in the brain were lower on the 2nd day than on the other 2 days. On the other hand, the ATL serum level on the 2nd day was higher than on the other 2 days. The ATL distribution in brain was heterogeneous on each of the three days and there were changes with time in its distribution in two brain portions, the anterior basal ganglia and the medulla oblongata + pons.

Amitriptyline↗

Heterogeneous distribution of mianserin in rat brain during chronic continuous infusion.

The mianserin (MIS) distribution in 12 brain regions was investigated after 2- and 14-day continuous MIS infusion, starting with 19 mg/kg/day on the first day. There was no significant difference between the 2nd and 14th day with respect to MIS concentration, brain/serum concentration ratio in whole brain or MIS serum level. The MIS distribution was heterogeneous on the 2nd and 14th day and did not change with time. The concentrations were highest in cortex and hippocampus and lowest in cerebellum, hypothalamus, and bulbus olfactorious and septum. This distribution pattern differs from those found with tricyclic antidepressant drugs.

Animals↗

Sleep spindles in twins.

Sleep spindle characteristics and spindle power periodicity were studied in 4 identical and 3 fraternal twin pairs (mean age, 16 years). There were no significant genetic effects such as concordance between the identical twins and discordance between the fraternal twins for mean duration, mean amplitude and mean frequency of spindles. Spindle periodicity, which is correspondent to the sleep cycle, was visually more similar between the identical twins than between the fraternal twins. These observations suggest that the sleep cycle which is expressed by periodic appearance of spindle powers is genetically determined. On the other hand, some spindle characteristics and some physical measures had significant relationships. These relationships may suggest that some spindle characteristics are influenced by the individual development rather than by a genetic trait.

Adolescent↗

[Performance of various prepared abutment forms. Posterior fixed bridge abutment].

The clinical techniques of the students were examined by analyzing the results of some measurements on the side wall inclination as a width and height of the full formed abutment of posterior fixed bridge, and the results of full covered crown data were compared. Significant differences in the inclination degree to the axis between upper and lower were not noticed in either premolars or molars on the mesio-distal side wall and bucco-lingual side wall, and were noticed between premolars and molars of the same jaw on both side walls. Margin diameter and height of diameter of the premolars showed a closer rank correlation than molars in mesio-distal side wall, but in bucco-lingual side wall, molars showed a closer rank correlation than premolars.

Bicuspid↗

[Intracytoplasmic eosinophilic inclusions in dorsal root ganglia and spinal nerve roots from an autopsy case of unusual familial ataxia with cerebrospinal fluid abnormality].

Studies were performed on the light and electron microscopic structures of the dorsal root ganglia (DRG) and spinal nerve roots of the 4th lumbar nerve obtained by autopsy from a 49-year-old man with unusual familial ataxia, who showed varied neurological manifestations such as progressive ataxia, action tremors, pyramidal tract signs, mild deep sensory disturbances and autonomic dysfunctions during a 30-year period of illness, and had 2 siblings, one male and female, similarly affected and close consanguineous marriages in his family. On laboratory examinations, blood chemistry disclosed no significant findings. Repeated spinal taps showed constant xanthochromia and elevated protein in the cerebrospinal fluids. A PEG and cranial CTs revealed a progressive brain atrophy. NCVs and EMGs in the extremities were within normal limits. There was no chromosomal abnormality. Light microscopically, intracytoplasmic eosinophilic inclusions (IEIs) with pale rim, which showed varied sizes and rounded shapes, occurred within neurons in the DRG, particularly in small neurons. Many of the small neurons had numerous IEIs, and several rounded granules with a high degree of eosinophilia, measuring below 5 microns in diameter. Generally the small neurons showed atrophic, while most large neurons showed no remarkable change although they had a small number of IEIs and granules located in the perikaryal periphery. Most satellite cells, and some Schwann cells in the DRG, ventral and dorsal roots had IEIs similar to those seen in the neurons. No IEIs occurred intraaxonally, and there was seen no degenerative process in the DRG and roots except a connective tissue fiber proliferation in the DRG.(ABSTRACT TRUNCATED AT 250 WORDS)

Ataxia↗

[A biphasic changes in the seizure-threshold in kindling seizure development induced with low-frequency electrical stimulations].

Seven cats were stimulated once a day with low-frequency electrical stimulations to assess the serial changes of development. Each animal had been implanted stereotaxically with a stimulating electrode into the left-side ventral hippocampus and with recording electrodes into the right-side ventral hippocampus, the bilateral dorsal hippocampus. We applied the stimulations at 10:00 AM, bipolarly with 2 mA-biphasic square-wave pulses (1 msec durations). The pulse-interval was set at 300 msec. If epileptic afterdischarge could not be triggered on EEG with this pulse-interval, a 100msec-interval stimulation was applied after 15 min-rest period. The number of stimulating pulses required for a triggering of afterdischarge was defined as pulse-number threshold (PNT) which was used as an indicator of the seizure-threshold. The duration of each seizure on EEG (afterdischarge duration, ADD) was also recorded and the seizure-related behaviors were classified into 5 stages as follows: 1, staring or immobility; 2 appearance of facial twitching or head nodding ; 3, tonic convulsions of the right-side fore-paw or a head turning toward the right-side; 4, generalized clonic convulsions; 5, generalized convulsions with a falling down. The kindling procedure completed within a mean of 36.5 days, and all the animals presented stage-5 seizures. At the completion of kindling, PNT was determined at 10.5 +/- 1.8 (mean +/- SE). During the kindling process PNT showed a sudden decrease in the initial part of stage-1 (within a mean of 3.8 days) and a gradual increase from stage-3 to stage-5. ADD showed a simple increasing function of the development of seizure-stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

[Effects of phenobarbital and phenytoin on hippocampus generating seizures].

We have recently reported some pharmacological studies using a kindling model of epilepsy induced with 1-3 HZ electrical stimulations, referred to as the low-frequency kindling. Since a previous study showed that the effects of psychotropic drugs on limbic seizures were dependent on the location of epileptic focus, we decided to study acute and chronic effects of anticonvulsants on the hippocampus generating seizures to compare with the results of a previous study of the amygdala generating seizures, which was done under the same conditions with this study. The number of stimulating pulses required for the triggering of epileptic afterdischarge (pulse-number threshold) was used as the indicator for the seizure threshold. Duration of after discharge (ADD), ictal and interictal behaviors of the subjected 7 cats, and serum drug levels were also recorded. A dose-dependent increase of serum drug levels was confirmed in each drug, and the values were well comparable with the optimal range in clinical use. In acute experiment PB 5 mg/kg p.o. produced no significant effect on PNT and ADD. PB 10 mg/kg increased PNT significantly (p less than 0.02) at 2 hrs after administration without affecting ADD, but 4 cats presented the seizure-stage regressions. PB 20 mg/kg increased PNT (p less than 0.02) and decreased ADD (p less than 0.02) with the seizure-stage regressions of all the tested cats at 2 hrs after administration, and increased PNT (p less than 0.05) without affecting ADD and seizure stage at 96 hrs after administration. PHT 5, 10, 20 mg/kg decreased PNT (p less than 0.05, 0.02, 0.02, respectively) without affecting ADD at 2 hrs after administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Amygdala↗

[Classification of crown forms. Morphological interrelationship between upper central incisors and facial forms].

The interrelationship between tooth forms and facial outlines is represented in multivariate linear combinations. Principal Component Analysis was used in this study as an expression of morphological features. Measured data on the tooth and the face could be classified into 4 types by the first and second principal components of multivariate analysis. Of the 117 subjects, the largest group of 33 (28.9%) had of oval faces and were Class III for the face and Class II for the teeth, respectively. Of the 117 subjects, 36 showed morphological similarity between teeth and face.

Face↗

[Principal component analysis of the masticatory motion path during gum chewing].

This study examined the characteristics of masticatory motion path using multivariate analysis. Principal component analysis was selected as the method and various important results were revealed as follows; Approximately 70% of the information describing gum chewing motion was explained by three principal components. From factor loading, the first principal component explains back and forth movement from the end of the opening phase to the closed position, the second principal component explains left to right movement at the onset of the mouth opening phase, and the third principal component explains left and right movement at about the position of maximum opening. Using scatter diagrams combining the first and second principal components, as well as the first and third principal components, we were able to recognize delicate differents among the subjects, but to the different strokes of any subject, characteristic patterns were emerged.

Chewing Gum↗

Distribution of clomipramine in various brain regions of rats under steady-state serum concentrations.

The clomipramine (CMP) distribution in 12 regions of rat brain was investigated 2 and 7 days after subcutaneous minipump implantation. The results of serial blood samplings during 7 days indicated that steady-state CMP serum levels were achieved from experimental day 2. The regional CMP distributions in the brains were uneven on both the 2nd and 7th experimental days. On both test days the CMP concentrations were higher in the cerebral cortex and hippocampus than those in the other regions, and those in the cerebellum and bulbus olfactorius and septum were lower. When the serial fluctuations of the CMP levels were examined in 12 brain regions, there were significant differences between days 2 and 7 in the following four regions: the anterior basal ganglia, hypothalamus, bulbus olfactorius + septum and amygdala.

Animals↗

Effects of chronic haloperidol treatment on amygdaloid seizure generation in cats.

We evaluated the effect of chronic haloperidol treatment (0.5-2 mg/kg/day, 21 day) on amygdala-generating seizures using a kindling procedure induced by low frequency electrical stimulations. The number of stimulating pulses required for triggering of epileptic afterdischarge (pulse-number threshold; PNT) is the indicator of the seizure generating threshold. A PNT decrease occurred, followed by a PNT increase toward the pre-treatment level during high-dose, chronic haloperidol treatment. A PNT increase occurred, followed by a PNT decrease toward the pre-treatment level during the withdrawal period after the high-dose treatment. A decrease of the triggered seizure duration occurred during the high-dose treatment. These results indicate that a transient decrease of seizure generating threshold occurs during chronic haloperidol treatment, and withdrawal of the drug is followed by what appears to be a rebound phenomenon. We suggest that this effect might be related to the antipsychotic potency and associated neurochemical changes known to be caused by chronic haloperidol treatment.

Amygdala↗

Effects of chronic lithium treatment on limbic seizure generation in the cat.

The effect of chronic lithium administration (2.2-8.7 mEq/kg/day, 17 days) to the cat on seizure initiation in the amygdala and hippocampus was assessed by the low-frequency kindling technique. Lithium 4.3 mEq/kg/day PO, producing a serum lithium level between 1.2 and 1.6 mEq/l, caused an elevation of the amygdala seizure threshold on treatment days 5-9. In contrast, the same dosage caused a transient reduction of the hippocampus seizure threshold on treatment days 13-17 and on withdrawal days 21-25. Lithium 2.2 mEq/kg/day PO caused no significant effect on the parameters of the two types of seizure. Lithium 8.7 mEq/kg/day PO caused severe behavioral changes and did not permit chronic treatment. These results indicate that the effect of chronic lithium treatment on limbic seizures is dependent on the location of epileptic focus.

Animals↗

Influence of sex on age at onset of schizophrenia.

The age at onset of schizophrenia was investigated in 2,417 inpatients (1,433 males and 984 females) meeting the DSM-III criteria for schizophrenia. About 80% of the patients became schizophrenic before the age of 30. The mean age at onset of the male patients was slightly earlier than that of the female patients. There was a higher cumulative percentage of the male patients who became affected at each age quinquennium. More men than women became schizophrenic before the age of 30.

Adult↗

A relationship between clomipramine brain concentration and its effect on serotonin metabolism.

The relationship between clomipramine (CMP) brain concentration and its inhibitory effect on serotonin (5HT) turnover was investigated in rats treated with a single dose and multiple doses of CMP. CMP reduced the 5-hydroxyindole acetic acid (5HIAA) brain levels in two groups of rats. Concerning the 5HT turnover measured by the probenecid (PBC) technique, there were significant correlations between the CMP brain level (x) and 5HIAA brain level (y) after PBC injections in both acute and chronic experiments. The regression lines for the respective groups were y = 764 - 117 log x (r = 0.84, P less than 0.001) and y = 770 - 97.7 log x (r = 0.68, P less than 0.001). The regression coefficient for the acute experiment was greater than that for the chronic one (p less than 0.001), indicating a less dose-response in the latter. From these findings, the acute dosing with CMP seemed to reduce the 5HT turnover without reference to the dose but a prolonged administration seemed to vary in its effect. This may be due to a compensatory mechanism in the 5HT system induced by chronic CMP-treatment.

Animals↗

Familial ataxia with abnormal CSF, with special reference to an autopsy case from three affected siblings.

We report here the clinical features of 3 affected siblings and neuropathological findings of the CNS from an autopsied case among them. Their common clinical features consisted of cerebellar ataxia and tremors through movements and postures. Two of the 3 siblings showed autonomic abnormalities, hard-of-hearing, pyramidal sign and areflexia. Then they always had xanthochromia and an elevated protein without pleocytosis in their CSFs. Neuropathologically, intracytoplasmic eosinophilic inclusion bodies were found in the neurons of some restricted nuclei or nerve cell groups of the brain stem, cerebellum and spinal cord. Similar bodies appeared also in glial, ependymal and choroid plexus epithelial cells. Such eosinophilic bodies are thought to consist of protein-rich substances from histochemical properties, and result from an unknown inherited metabolic error.

Adult↗

Effects of chronic treatment of methamphetamine and imipramine on amygdaloid seizure's generation.

We assessed the effects of chronic treatment of methamphetamine (1-2 mg/kg/day, i.p., 17 days) and imipramine (2-8 mg/kg/day, p.o., 17 days) on amygdala-generating seizures using the kindling method induced by low-frequency electrical stimulations. The number of stimulating pulses required for the triggering of epileptic afterdischarge (pulse-number threshold: PNT) is the indicator of seizure generating threshold. A PNT elevation followed by its reduction occurred, compared to the pretreatment level, during a 2 mg/kg/day chronic methamphetamine treatment. A reduction in the PNT and triggered afterdischarge durations occurred during a chronic imipramine treatment. These results indicate that both methamphetamine and imipramine reduced the seizure generating threshold by repeated applications. It is suggested that this finding might be related to the psychoactive potency and associated neurochemical changes which are known to be caused by these drugs.

Amygdala↗