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Biomedical subjects

K Yajima

Publications and source records attributed to K Yajima.

At least 109 records · Page 6Linked to original sources
PubMed1979

Neuronal degeneration in the brain of the brindled mouse. II. Ultrastructure of neuronal inclusions in the cerebral cortex.

Two types of intra-cytoplasmic inclusions were observed in many cortical neurons of hemizygous brindled mutant mice (MObr/Y) which survived for more than 1 month. One type is an electron-lucent vacuole containing numerous vesicles and membrane fragments, some arranged concentrically, and the other consisted of electron-dense matrix with myelin figures. These inclusions were, as a rule, found near the axonal hillock where abnormally enlarged mitochondria were often present. In view of the presence of many features suggestive of autophagic vacuoles and absence of such inclusions in the oldest mice (91 days old), we hypothesize that these inclusions probably represent a focal repairing process of neurons from the sublethal injury.

Aneuploidy↗
PubMed1979

Neuronal degeneration in the brain of the brindled mouse--a light microscope study.

The brindled mouse (Mobr) is a neurological mutant mouse with a deficiency in copper transport. This mutant has many clinical as well as biochemical features in common with Kinky hair syndrome (KHS) in humans (Tab. 1). Male hemizygotes (Mobr/Y) are characterized by the absence of fur pigment and curly whiskers. They become inactive, losing weight at around the 10th-12th post-natal day. They usually die in an emaciated state around the 15th-16th postnatal day. The brain weight is usually about three fourths of that of littermate controls. Microscopically, widespread neuronal degeneration was noted in the cerebral cortex and thalamic nuclei of male hemizygotes after the 12th post-natal day. The degeneration continued to increase until death. Scattered degenerated cells were also noted in the cerebellum. No such degenerative changes were observed in the brain of female heterozygotes (Mobr/+) or in normal or starved littermates. These degenerative changes of neurons in the brindled hemizygote mouse will be compared with the neuropathological changes observed in KHS and in experimental animals with copper deficiency, and the possible pathogenesis of these changes will be discussed.

Age Factors↗
PubMed1979

Demyelination and remyelination in the rat central nervous system following ethidium bromide injection.

Intracisternal injection of ethidium bromide induced status spongiosus with prominent degenerative changes in oligodendroglia in the subpial regions of the central nervous system of the rat. Chronologic investigation of the lesions has revealed that status spongiosus resulted in myelin degeneration, and by the 6th day postinjection many axons were demyelinated. At this time, numerous debris-filled phagocytic cells were observed among the totally naked axons. Vesicular transformation of myelin was the common degenerative change. Features suggestive of separation of myelin lamellae by phagocytic cells were also observed. In the demyelinated areas, oligodendroglial cells disappeared completely. By the 12th day postinjection, remyelination was apparent and numerous active oligodendroglia appeared in association with thinly myelinated axons. Some central nervous system axons were myelinated by Schwann cells. These patterns of demyelination and remyelination observed in ethidium bromide-treated rats were compared with those observed in other demyelinating conditions of varied etiology such as experimental allergic encephalomyelitis, diphtheria toxin, or lysolecithin injection and cuprizone intoxication.

Animals↗
PubMed1978

[A case of aneurysm of the left internal acoustic meatus (author's transl)].

A case of aneurysm of the left internal acoustic meatus has been reported. The patient was 53-year-old man who was admitted with the history of sudden onset of a severe occipital headache 18 days previously. He also noted nausea, vomiting and became drowsy at that time. He was seen at a local clinic and a lumbar puncture showed bloody fluid. The next day his level of consciousness improved but he noted left tinnitus and neck stiffness. On admission, he only complained of a left tinnitus. The rest of the neurological examination was normal. Craniogram was of no abnormal findings. Cerebral angiogram showed an aneurysm at the left internal acoustic meatus fed by the left internal auditory artery. At operation, the aneurysm was clipped at the entrance of its feeding artery via retroauricural-retromastoidal craniectomy. The postoperative course was satisfactory except for the decrease of the left auditory acuity to 50dB. Postoperative angiogram revealed a complete disappearance of the aneurysm. In the literature only six cases have been reported, which were summarized in Figure 1. Clinical features of such an aneurysm are subarachnoid hemorrhage and symptoms of cerebello-pontine angle, namely tinnitus, hearing disturbance and facial palsy etc. Besides, on skull x-ray film, sometimes enlargement of the internal acoustic meatus has been found.

Ear, Inner↗
PubMed1977

Sub-plasmalemmal linear density: a common structure in globoid cells and mesenchymal cells.

Sub-plasmalemmal linear densities of variable length (0.1 approximately 1.0 mu) were found to be a constant feature of globoid cells in human as well as in canine globoid cell leukodystrophy (GLD). Similar densities were also observed in experimental globoid cells and epithelioid cells in chronic granuloma but not in glial cells. The linear densities always appeared without any relation to basal laminae. These observations together with the other reports of similar structures in lymphoma, fibroma and sarcoidosis suggest that the sub-plasmalemmal density is a structure frequently observed in mesenchymal cells, and may be another supporting feature for possible mesenchymal origin of globoid cells.

Animals↗
PubMed1977

Canine globoid cell leukodystrophy. Part 1. Further ultrastructural study of the typical lesion.

The ultrastructural changes of typical lesions in canine globoid cell leukodystrophy (GLD) have been studied. The globoid cells were located in the cerebral parenchyma as well as in the perivascular Virchow--Robin space. Features suggestive of a passage of the globoid cells from the cerebral parenchyma to the Virchow--Robin space were also observed through the interruptions in the basal lamina. The globoid cells had numerous thin pseudopods and contained various cytoplasmic inclusions which have been described previously. Detailed studies of these inclusions suggest that they represented aggregates of filamentous or linear sub-unit structures. Typical oligodendroglial cells were found on only a few occasions. Both globoid cells and oligodendroglia contained myelin debris, dense bodies and honey-comb like inclusions composed of numerous small myelin figures. In a few instances, crystalline polygonal inclusions identical to those found in the globoid cells, were found in the cytoplasm of the cells which were, with reasonable certainty, identifiable as oligodendroglia. In less affected areas where myelin was still present, degenerating oligodendroglia, with or without recognizable inclusions, were frequently encountered. Astrocytes and endothelial cells contained concentric lamellar inclusions and dense bodies but did not contain the tubular inclusions as seen in globoid cells. The possible significance of the ultrastructural features in regard to the pathogenesis of the GLD have been discussed.

Animals↗
PubMed1975

[Spontaneous spinal subarachnoidal hematoma--case report (author's transl)].

"Spontaneous intraspinal canal hematomas' are rare clinical conditions. These are classified as epidural, subdural and subarachnoid. Especially, subarachnoid hematoma is rare only two cases being reported by Bouzarth (1968). We have reported surgical treatment of a female with intraspinal canal subarachnoid hematoma. The patient presented with sudden onset of backpain, followed by paraplegia, sensory impairment and urinary retention. A lumbar tap revealed bloody CSF a complete block. A left vertebral angiography was normal. However, a myelography showed a filling defect at Th5. A laminectomy was performed and a subarachnoid hematoma at the Th1-5 level was completely removed. Etiology of the legion was not identified. The patient made an uneventful recovery. This case suggests that intraspinal canal hematoma needs an operation as soon as possible, especially with urinary retention.

Adult↗