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Biomedical subjects

M Kurachi

Publications and source records attributed to M Kurachi.

178 records · Page 10Linked to original sources
PubMed1980

The action of chlorphenesin carbamate on the frog spinal cord.

Studies were carried out to elucidate the mechanism of action of chlorphenesin carbamate (CPC) and to compare the effect of the drug with that of mephenesin on the isolated bullfrog spinal cord. Ventral and dorsal root potentials were recorded by means of the sucrose-gap method. CPC caused marked hyperpolarizations and depressed spontaneous activities in both of the primary afferent terminals (PAT) and motoneurons (MN). These hyperpolarizations were observed even in high-Mg2+ and Ca2+-free Ringer's solution, suggesting that CPC has direct actions on PAT and MN. Various reflex potentials (dorsal and ventral root potentials elicited by stimulating dorsal and ventral root, respectively) tended to be depressed by CPC as well as by mephenesin. Excitatory amino acids (L-aspartic acid and L-glutamic acid) caused marked depolarizations in PAT and MN, and increased the firing rate in MN. CPC did not modify the depolarization but abolished the motoneuron firing induced by these amino acids. However, mephenesin reduced both the depolarization and the motoneuron firing. The dorsal and ventral root potentials evoked by tetanic stimulation (40 Hz) of the dorsal root were depressed by the drugs. These results indicate that CPC has an apparent depressing action on the spinal neuron, and this action may be ascribed to the slight hyperpolarization and/or the prolongation of refractory period.

Action Potentials↗
PubMed1979

Recovery from alexia without agraphia: report of an autopsy.

The patient is a 58-year-old Japanese teacher of German literature who suffered twice from cerebrovascular accidents, showing alexia without agraphia. Pathological examination showed an old infarct in the posterior two-thirds of the fusiform and almost the whole lingual gyrus, involving the posterior border of the parahippocampal gyrus in the left hemisphere. The left cuneus and the calcarine cortex were preserved. There was degeneration of the lower third of the splenium of the corpus callosum, extending to its occipital radiation and tapetum on both sides. Comparing clinico-pathological findings of the 31 known autopsy cases, it was proposed that the lesion of the left spleno-lingual system produces alexia without agraphia but it may ameliorate. In addition, when spleno-cuneate system is also involved alexia becomes persistent and it may accompany object agnosia or optic aphasia.

Agraphia↗
PubMed1979

Amyotrophic lateral sclerosis with temporal lobe atrophy.

Clinical and neuropathological findings are reported on a 48-year-old man who developed progressive bulbar palsy, muscle atrophy of four extremities, and hyperreflexia. Duration of the illness was about 19 months. Moderate personality changes were observed during his hospitalization. Neuropathological examination revealed the presence of an ALS: severe loss of the large motoneurons in the spinal anterior horns, and degeneration of the corticospinal tract, more prominent on the left side. The hypoglossal, the facial, and the motor trigeminal nuclei were also involved, but the oculomotor, the trochlear and the abducens nuclei were well preserved. There was bilateral, but more pronounced on the right, atrophy of the temporal poles consistent with the lesions of the temporal types of Pick's disease. This case indicates the simultaneous occurrence of degenerative diseases of the CNS, and the correspondence of laterality between the temporal lobe and the spinal cord may suggest a common etiology of these two types of disease processes.

Amyotrophic Lateral Sclerosis↗
PubMed1979

First autopsy report of a multiple sclerosis case in Hokuriku District of Japan.

The first autopsy of a case of multiple sclerosis from the District of Hokuriku was reported. The patient, a 50-year-old house-wife, born in Toyama Prefecture, had noticed a paresthesia of her face, fatigue, numbness and weakness in the right limbs, dimness of vision and gait disturbance at ave 44. Furthermore, in the course of the disease, she had suffered from visual disorder, tetraplegia, hyperreflexia, pyramidal signs and cerebellar syndroms such as dysarthria, nystagmus, intention tremor and ataxia. She also showed symptoms of euphoria and dementia. After a course of six years she died of bronchopneumonia. Remissions and exacerbations were noted four times during her clinical history. Histopathologically, there were many recent and old demyelinating lesions of varying sizes and shapes in all parts of the central nervous system, namely the cerebrum, brainstem, spinal cord and optic nerve. In contrast to the clinical symptoms, the cerebellum itself revealed less plaques than the other areas of the brain. According to the observed distributions of the lesions, our case can be classified as belonging to the optico-cerebro-spinal type in the Ikuta and Zimmerman classification. The demyelinated lesions were characterized by a perivenular distribution of the plaques, lack of tissue necrosis, paucity of inflammatory reaction and marked fibrous gliosis of varying degrees.

Bronchopneumonia↗
PubMed1978

Congenital hepatic fibrosis. A case report with study of three dimensional reconstruction of serial sections of the liver.

A patient who developed pancytopenia and hepatosplenomegaly with portal hypertension is described. Liver wedge biopsy at the time of operation showed typical histology of congenital hepatic fibrosis. Renal surgical biopsy revealed tubular ectasia. A continuous anastomosing network of the biliary tree was observed by reconstruction of serial sections of the liver. Some parts of the network were dilated and no isolated bile ducts were present.

Adolescent↗
PubMedDate not supplied

Acute effect of anticonvulsants on amygdaloid kindled seizures induced with low-frequency stimulations.

Acute effects of several antiepileptic drugs on low-frequency amygdaloid-kindled seizures were assessed. The number of stimulating pulses required for the provocation of epileptic afterdischarge (pulse-number threshold, PNT) was used as an indicator for the seizure-generating threshold. The duration of epileptic afterdischarge (AD duration) was used as an indicator for the severity of the induced seizures. Phenytoin (PHT) and carbamazepine (CBZ) reduced AD duration more than did elevating PNT. Conversely, phenobarbital (PB) and diazepam (DZP) elevated PNT more than did reducing AD duration. Weak effects on the two indicators, valproic acid (VPA) and ethosuximide (ESM), were observed. Low-frequency kindling may be a useful experimental model of epilepsy in drug-assessments.

Amygdala↗
PubMedDate not supplied

Progressive dysphasic dementia with localized cerebral atrophy: report of an autopsy.

A 64-year-old Japanese woman showed an initially aphasic disturbance followed by complete mutism, progressive dementia, parkinsonism and muscular atrophy. Autopsy revealed localized cortical atrophy confined to the pars triangularis, pars opercularis of the inferior frontal gyrus, supramarginal and angular gyri of the inferior parietal lobe, precuneus and posterior half of the middle and inferior temporal gyrus predominantly on the left hemisphere. The right cerebellar hemisphere showed crossed cerebellar atrophy with shrinkage of the right middle cerebellar peduncle. In the atrophied cerebral areas there were diffuse outfall of neuronal cells in all cortical layers and remaining neurons generally showed simple atrophy, and there were a few swollen neurons. Gliosis of the subcortical white matter was confined to the affected gyri and GFAP positive astrocytes were observed in the 1st, 2nd, 5th and 6th layers of the cortex. In addition, the degenerative changes of the substantia nigra, gliosis of the amygdaloid complex and inferior olivary nucleus were bilaterally observed. The distribution and characteristics of the cortical and white matter degeneration are different from those of Pick's disease, and it is likely that this case belongs to a group of so-called degenerative dysphasic dementias.

Aphasia↗