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Biomedical subjects

K Kawamoto

Publications and source records attributed to K Kawamoto.

At least 307 records · Page 17Linked to original sources
PubMed1980

Reversibility of the endolymphatic potential after transient anoxia.

The effect of transient local anoxia (10 to 120 min) upon the endolymphatic potential (abbr. EP) was observed in 30 normal guinea pigs. The recovery of the EP was complete in the animal subjected to 10 min anoxia and almost complete in 20 min anoxia. When the duration of anoxia was 30 min or longer, the recovery of the potential was incomplete, and the longer the duration of anoxia, the lower the level of the EP after reoxygenation. These results were discussed in relation to the possible role of a transient anoxia upon sudden deafness.

Action Potentials↗
PubMed1980

[Flow cytometric studies of human brain tumors. Part I: Human malignant brain tumors (author's transl)].

This report concerns the distribution of the DNA content in cells obtained from seven nonneoplastic, human brain tissue specimens and from eight different kinds of malignant human brain tumors of 30 patients. Analysis was carried out by flow cytometry suing suspensions of single separated cells stained with propidium iodide as DNA-intercalating fluorochrome. Normal, non-stimulated lymphocytes served as diploid controls. An average of 91% of the cells from non-neoplastic brain tissue was diploid (2C) and these cells were presumable in G0 or G1 stage of the cell cycle. In specimens from malignant brain tumors the proportion of diploid cells in G0 or G1 stage varied between 35 and 89%. In these specimens polyploid (including triploid, tetraploid and hypertetraploid) cells were frequently observed. From the distribution of their DNA content the 14 specimens of glioblastomas were classified into 3 types. Specific patterns were noted in type III-b which was characterized by two peaks having the same heights. The cerebral metastasis displayed the greatest variations in ploidy and these tumors, on basis of their DNA distribution were divided into 3 types. As shown in the present study the cytofluorometric analysis of malignant brain tumors revealed characteristic features: 1) multiple DNA peaks, 2) wide ploid variations ranging from 2C to 8C, 3) variability of DNA content patterns and distribution, 4) relatively large portions of cells in S and G2 + M phase of the cell cycle, 5) presence of heteroploid and polyploid cells. Because flow cytometry has distinct advantages over other methods in permitting rapid analysis of large populations of cells with a high degree of reproducibility, results obtained with this technique may be of significant clinical importance.

Brain Neoplasms↗
PubMed1980

[A case of large germinoma in bilateral frontal region (author's transl)].

Though most of ectopic pinealoma occurs in the midline of cerebral base, only ten cases of frontal subcortical germinomas were reported in Japan as far as we know in literature. The patient, 20 year-old male, was admitted to our hospital because of blurred vision of the right eye and somnolence. Neurological examination on admission revealed bilateral choked discs and impaired visual acuity of both eyes with visual field defect of the right eye. A large deep bifrontal tumor was noted by cerebral angiography and pneumoventriculography done at the time of ventricular drainage. After subtotal removal of left frontal tumor and bifrontal V-P shunt, he came alert. No abnormality of posterior part of third ventricle was noted on the post-operative pneumonencephalogram. As the microscopic examination revealed that the tumor was germinoma of two-cell pattern, Co60 with a total dose of 5,900 rads was irradiated to the rest of the tumor. Brain scan with Tc99m 6 months after the surgery showed the disappearance of the tumor and CT scan 3 years later confirmed no recurrence of the tumor. Fine structure of the tumor was also presented and discussed.

Adult↗
PubMed1979

An ultrastructural study of cultured human meningioma cells.

Ultrastructural alterations in human meningioma cells growth in vitro are reported. In early passages the cells retain some of the characteristic features of the original tumors. These include interdigitations associated with intercellular junctional devices (e.g., desmosomes, gap junctions). However, with repeated subculture these features tend to be less frequent. Typical whorl formations are observed only in primary cultures. The number of cytoplasmic filaments, lipid inclusions and other dense bodies increases with time in culture. Cytoplasmic invaginations into nuclei and the appearance of very large cells become more frequent in repeatedly transferred cultures.

Cells, Cultured↗
PubMed1979

Flow cytometric analysis of the DNA distribution in human brain tumors.

Flow cytofluorometric analysis was used to determine the distribution of the DNA content in cells from selected areas of normal human brain and in benign and malignant brain tumors. Propidium iodide was employed as DNA fluorochrome and the analysis was carried out on a suspension of single cells. Normal, nonstimulated human lymphocytes were used as diploid controls. With nonneoplastic tissue an average of 91% of the cells were diploid (presumably in G0 or G1 stage of the cell cycle). The cells of most benign tumors were mainly diploid (77-98%), nine specimens of pituitary adenomas had large numbers of aneuploid cells. In glioblastoma multiforme the proportion of diploid cells was significantly diminished and polyploid cells were frequently seen. Similar results were obtained in other malignant tumors, with metastatic tumors showing the greatest ploidy variation, which included triploid, tetraploid, and hypertetraploid cells. The analytical method used provides valuable information of significant clinical importance on the DNA distribution in brain tumor cells.

Aneuploidy↗
PubMed1979

Foreign bodies in the tracheobronchial tree. A review of 110 cases.

During the period from 1966 to 1974, 110 cases of foreign bodies in the tracheobronchial tree were treated in our clinic using the ventilation bronchoscope under general anesthesia, and good results were obtained. Upon reviewing the case records, the ventilation bronchoscope was evaluated to be safe even for infants. Of the 110 cases, male predominance was 2 to 1, and 76 infants were under 3 years of age. Although, various types of foreign bodies were removed, almost half of the cases involved peanuts. Generally, the right bronchus was obstructed more frequently than the left. However, in children under 6 years of age, this tendency was inverted especially in 53 cases involving peanuts. The relationships between the age factor and the location of the foreign bodies are discussed.

Adolescent↗
PubMed1979

Effect of ethacrynic acid upon the peripheral vestibular nystagmus.

The effect of ethacrynic acid (ETA) upon pendular rotation nystagmus and paralytic nystagmus was examined using 61 guinea pigs. 100 mg/kg ETA reduced these nystagmus but 30 mg/kg ETA had on effect. Galvanic nystagmus, Bechterew's compensatory nystagmus, OKN and EEG were not affected by 100 ng/kg ETA. These results are highly suggestive that the inhibition of the peripheral vestibular nystagmus by ETA is mainly due to the reduction of the ampullar endolymphatic potential.

Action Potentials↗
PubMed1979

Ultrastructural changes of the nerve elements following disruption of the organ of Corti. II. Nerve elements outside the organ of Corti.

Various stages of changes in the nerve fibers, spiral ganglion cells, and satellite cells from the guinea pig cochlea 3 to 137 days after perilymphatic perfusion with streptomycin solution (2 and 20%) were observed electron microscopically. Initially, the axoplasms of the cochlear nerve fibers became swollen or pyknotic. Then, the axons disappeared and myelin lamellae disrupted. The Schwann cells shrank and degenerated, though their basement membranes survived for a time. Regeneration of the cochlear nerve fibers began with extension of axonal sprouts into the tube of the basement membrane and surviving Schwann cells, which still contained myelin debris. Only one of the axonal sprouts matured for myelination. These regenerating cochlear nerve fibers were found in the osseous spiral lamina, modiolus and internal auditory meatus, but these fibers atrophied and disappeared afterward. Retrograde degeneration occurred in the olivo-cochlear bundle. Some of the efferent myelinated fibers also showed temporary regeneration.

Animals↗
PubMed1979

[The fine structure of granulocytic sarcoma (author's transl)].

Granulocytic sarcoma, a rare manifestation of leukemia, can present as solid and invasive tumors in the central nervous system. We report electron microscopic findings in two such cases of granulocytic sarcoma in this communication. The first case is a granulocytic sarcoma involving mainly the left frontal dura with invasion of the underlying leptomeninges and brain. This was the initial presentation of acute myelogenous leukemia that became apparent seven months later. The second case is a granulocytic sarcoma involving the cervical spine and epidural soft tissue in a known case of chronic myelogenous leukemia. Electron microscopic studies confirm the presence of immatuure granulocytic cells with specific granules which distinguish these cases from other tumors such as a malignant lymphoma. Granulocytic sarcoma should be considered in the differential diagnosis of neurosurgical cases which present clinically as acute intracranial dural or spinal epidural tumors.

Adult↗
PubMed1978

Flow-through cytometry of meningiomas and cultured meningioma cells.

Flow cytometric techniques were used to compare the DNA content, size and viability of meningioma cells obtained directly from surgical specimens with the same cells after a period of culture. Cells isolated from the original meningiomas and cells in primary culture was similar with regard to size and DNA content, regardless of the histologic subclassification of tumor. The cell populations were essentially diploid with a small proportion of tetraploid cells. Viable cells were smaller and more uniform in size than the nonviable cells. An increase in the number of cells having an elevated DNA content was seen with cultures repeatedly transferred. The latter results suggest that any transfer of information from long-term cultured meningioma cells to the in vivo situation must be done with caution.

Aged↗
PubMed1978

[The fine structure of cell processes in astrocytoma (author's transl)].

Astrocytes, in normal tissue, may be characterized by their extensive processes which may be cylindrical in part but are sheet-like at their periphery where they serve to cover other structures. It becomes of interest ot determine the morphology of astrocytic processes after neoplastic transformation. We, therefore, examined the fine structure of 14 cases of astrocytomas. In general the fine structure of the cell bodies and the interior of the processes are fundamentally similar to those of normal or developing astrocytes. Differences are apparent at the cell periphery. These include less well developed cell junctions and usually only poorly formed peripheral expansions of the processes. Most sections through the processes appear round or oval rather than laminar in normal astrocytes. They often consist of small microvilli or pseudopodia-like protrusions. Whether these changes are due to the immaturity of the cell or to the lack of appropriate nearby target cells is not known.

Astrocytes↗