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Biomedical subjects

A Nishimoto

Publications and source records attributed to A Nishimoto.

At least 109 records · Page 6Linked to original sources
PubMed1984

Reverse cellular distribution of calmodulin to S-100 protein in primate brain.

Both calmodulin and S-100 protein are Ca2+-binding proteins of the EF-hand family. Immunocytochemical study revealed that calmodulin existed mainly in the neurons, whereas S-100 protein was localized primarily in the glial cells of the cerebral and cerebellar cortices of man and monkey. The observed reverse cellular distribution of calmodulin to S-100 protein in primate brain suggests that calmodulin might be replaced in its role as a Ca2+-binding protein by S-100 protein in the glial cells.

Animals↗
PubMed1984

Inhibition of nociceptive neurons by internal capsule stimulation.

The mechanism of pain relief by internal capsule (IC) stimulation was investigated in 32 adult cats. Nociceptive neuronal activity of the nucleus ventralis posteromedialis (VPM), responding to contralateral pulp stimulation, was suppressed by IC stimulation to a greater extent than activity in the posterior nuclear group (PO) or centre-median nucleus. On the contrary, suppression of neuronal firing by intraventricular morphine-HCl predominated in PO neurons. These results suggest that pain relief by IC stimulation may be mediated through inhibitory effects on nociceptive neurons of the thalamic sensory relay nuclei.

Analgesia↗
PubMed1984

Electrical stimulation of the posterior limb of the internal capsule for treatment of thalamic pain.

Electrical stimulation of the posterior limb of the internal capsule was performed in 7 patients with thalamic pain who had developed dysesthesia, hyperpathia and/or spontaneous burning pain. Ramped bipolar stimulation elicited sensory responses, such as warm or comfortable sensation. Follow-up from 9 months to 2 years and 7 months showed that 3 patients had a good result, two had fair and the remaining two had poor results. No serious side effects were seen. The mechanism of pain relief by the internal capsule stimulation is discussed.

Afferent Pathways↗
PubMed1984

Acute intracranial hypertension and brain-stem blood flow. An experimental study.

This study has been carried out to evaluate the effect of supratentorial mass lesions on the local cerebral blood flow (CBF) of the brain stem. Local CBF of the thalamus, inferior colliculus, and medulla oblongata, and supra- and infratentorial pressure were serially measured in 52 cats with intracranial hypertension produced by supratentorial balloon expansion. The mean control local CBF's in the thalamus, inferior colliculus, and medulla oblongata were 37.5, 42.1, and 30.7 ml/100 gm/min, respectively. At 20 to 30 mm Hg of supratentorial pressure, the local CBF of the thalamus started to decrease, and at 20 mm Hg of infratentorial pressure, the local CBF of the inferior colliculus began to decrease. Finally, at 40 to 60 mm Hg of infratentorial pressure, the local CBF of the medulla oblongata was affected. At the beginning of uncal herniation, indicated by anisocoria, the mean local CBF of the inferior colliculus abruptly decreased from 33.7 to 19.6 ml/100 gm/min in 16 cats. The Cushing response was evoked at a mean supratentorial pressure of 93.4 mm Hg and infratentorial pressure of 49.9 mm Hg in 16 cats. When the systemic arterial pressure was increased to the highest level in 13 cats, the mean local CBF of the medulla oblongata did not show significant change (a decrease from 22.8 to 20.9 ml/100 gm/min). The results suggest that at the beginning of uncal herniation, the local CBF of the upper brain stem markedly decreased. During the Cushing response, the local CBF of the medulla oblongata did not change significantly.

Acute Disease↗
PubMed1984

[Changes of the DNA synthesis and the amount of S-100 protein associated with the morphological differentiation of cultured glioma cells].

S-100 protein is a highly acidic protein unique to the nervous system and exists predominantly in the cytoplasm of glial cells in a water-soluble form. The exact biological function is still unknown in spite of its well-known biochemical properties. Some investigators have reported that the amount of S-100 protein in developing brains increased in proportion to the brain's development and differentiation. In order to clarify the relationship between S-100 protein and differentiation of glial cells the changes of DNA synthesis and the amount of the water-soluble S-100 protein were investigated on cultured rat glioma (C-6) cells in the course of the morphological differentiation induced by dibutyryl cyclic AMP (dbc-AMP). C-6 cells were cultured in Eagle's minimum essential medium supplemented with 10% fetal calf serum and incubated in a humidified atmosphere of 5% CO2-95% room air at 37 degrees C. Dbc-AMP was added to the media at the concentration of 1 mM, and the media were changed every 48 hrs. A flow cytometric analysis of DNA histogram patterns was performed to investigate the changes of DNA synthesis using a Cytofluorograf FC 4800 A-50 (Bio/Physics). The changes of the amount of S-100 protein were examined by micro-complement fixation assay as described by Levine using rabbit antisera against bovine S-100 protein. Dbc-AMP inhibited the growth of C-6 cells remarkably and induced morphological changes resembling normal astrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

[The role of brain-stem vasomotor centers on the neurogenic control of the neurogenic control of cerebrovascular tonus. Part 1: In special reference to cerebral blood volume and intracranial pressure].

An increase in cerebral blood volume (CBV) due to a decrease in cerebrovascular tonus has been though to be a major factor in the cause of acute brain swelling. It has been reported that the dorsomedial nucleus of the hypothalamus (DM), one of the brain-stem vasomotor centers, regulates cerebrovascular tonus. The DM and other vasomotor centers, such as the midbrain reticular formation (MBRF) and the reticular formation of the medulla oblongata (MORF), are connected through a series of nerve fibers. This experiment was designed to clarify the neurogenic control of the DM, MBRF, and MORF on cerebrovascular tonus. Using fifty-six cats, unilateral and bilateral DM(A 1.2, L2.0, H-10.0), MBRF (A4.0, L4.0, H0), and MORF (P10.0, L2.5, H-9.0) were coagulated stereotaxically with the condition of 15-10 mA for 1 minute. The lesions in the DM and MBRF were enlarged by increasing the current intensity of electrical coagulation. The effects of the increase on a number of simultaneously coagulated lesions were examined. Changes in systemic blood pressure (BP), intracranial pressure (ICP), and CBV were continuously recorded. Temporary increases in ICP (mean increase 16 mmHg, n = 14) and CBV were observed after unilateral coagulation of the DM. These increases were associated with transient systemic hypotension. The changes lasted only for approximately 5 minutes. The changes that occurred in ICP and CBV as a result of unilateral coagulation in the MBRF were almost the same as those that occurred after coagulation of the DM. In the latter case, the duration of the change was approximately 6 minutes with a mean increase of 12 mmHg (n=12).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

[Diencephalic syndrome--report of three cases].

Three cases of diencephalic syndrome, associated with brain tumors, are reported in this paper. Case 1. A 2-2/12-year old boy was initially admitted to our hospital because of failure to thrive which began at the age of three months. Physical examination revealed emaciation (weight, 7.8 kg), irritability and pallor without anemia. Horizontal nystagmus was seen. Laboratory studies were normal except for abnormally high plasma growth hormone (p-GH) which was incompletely suppressed by hyperglycemia (induced by glucose) and was not elevated by hypoglycemia (induced by insulin). A low grade astrocytoma of the optic nerve compression the hypothalamus was partially removed. After the operation followed by irradiation, p-GH returned to normal both in its basal level and in its reaction to insulin loading, then his gain of weight was accelerated. He was readmitted, however, at the age of 6 8/12 years with headache and vomiting. Since subtotal removal of the recurrent tumor and irradiation, preoperative symptoms have disappeared up to the present (7 9/12 years old). Case 2. A 3-9/12-year old girl was initially admitted because of failure to thrive since the age of 2 years. Examination on admission revealed emaciation (10.5 kg), irritability and right hemiparesis. Laboratory studies were normal except for high serum cholesterol (290 mg/dl). (p-HG was not measured) The patient had been well after the subtotal removal of the hypothalamic astrocytoma except occasional headache until the age of 6 years. She was readmitted at the age of 9 years with progressive emaciation.(ABSTRACT TRUNCATED AT 250 WORDS)

Astrocytoma↗
PubMed1983

Anterior inferior cerebellar artery aneurysm. Report of three cases.

Three cases of aneurysms of the anterior inferior cerebellar artery are reported. Two of the aneurysms were located in the cerebellopontine angle and one in the ventral portion of the pons. Through a suboccipital craniectomy, beck clipping was performed on one aneurysm, neck ligation on another, and coating on the third. A discussion of the surgical procedures and complications includes a review of previous reports.

Adult↗
PubMed1983

[Effect of ACNU, a water-soluble nitrosourea, on cell cycle of cultured glioma cells--flow cytometric analysis].

Cytotoxic and cytokinetic effects of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl) 3-nitrosourea hydrochloride (ACNU) on cultured rat and human glioma cells (C-6 and KC) were studied in vitro. Exponentially growing culture cells were exposed to ACNU at the final concentrations of 5 micrograms/ml, 20 micrograms/ml, and 80 micrograms/ml, respectively. The cytotoxic effect was evaluated by inhibition of cell growth and the cytokinetic effect was analyzed by DNA histogram using a flow cytometer. Inhibition of cell growth was dose-dependent in ACNU and C-6 cells were more resistant than KC cells. The growth of C-6 and KC cells were not inhibited at all by low concentrations of ACNU (5 micrograms/ml, 20 micrograms/ml), however, at these concentrations a marked accumulation of treated cells in S and G2+ M phases was evident. The accumulation in S and G2+M phases was dose-dependent and it was more prominent in KC than C-6 cells. ACNU-treated cells accumulated initially in S phase and then in G2+M phase. After maximum accumulation in G2+M phase, the cells seemed to be released into G1 or G0 phase. These results indicate that the cytokinetic effect of ACNU (5 micrograms/ml, 20 micrograms/ml) is more conspicuous than the cytotoxic effect on C-6 and KC cells.

Animals↗
PubMed1983

[Electrical stimulation of the posterior limb of the internal capsule for treatment of thalamic pain].

Electrical stimulation of the posterior limb of the internal capsule was performed in six patients with central pain due to vascular lesions of the thalamus. Three patients suffered from thalamic hemorrhage and the other three from ischemic insult. These patients developed dysesthesia, hyperpathia and spontaneous burning pain several months after cerebral vascular diseases. These severe pain were not relieved by any trials of anticonvulsants, psychopharmacological and analgesic drugs. Stimulating electrode system manufactured by Medtronic, Co. was implanted stereo-taxically in the posterior limb of the internal capsule which was 25 mm lateral to the posterior commissure. Ramped bipolar stimulation with a square pulse 2-3 V, 0.2 msec, 50 Hz elicited sensory response such as warm or comfortable sensation. Satisfactory relief of pain was obtained in most cases by 30-minutes-long stimulation twice or three times a day for various period of time ranging from 10 to 14 days. Long-term follow-up ranging from three months to two years showed that three patients had a good result (incomplete pain relief by stimulator with no medication required), two had a fair (incomplete pain relief by stimulator with decreased doses of medication) and another one had a poor result in which the pain had not been relieved with the stimulation in one month. No remarkable side effects were seen. These results indicate that the internal capsule stimulation is more effective and lasts longer than the various ablative methods to relieve central pain.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Hemorrhage↗
PubMed1982

Characteristics of a brain lymphoma cell line derived from primary intracranial lymphoma.

A brain lymphoma cell line, designated TK, was established from biopsy material of a patient with primary intracranial lymphoma. The TK cell line grew in suspension with clumps of cells and consisted of primitive lymphoid cells. TK cells and original lymphoma cells from which the cell line was derived bore surface immunoglobulin and lacked Epstein-Barr virus-determined nuclear antigen. Transplantation of the TK cells into immunosuppressed newborn hamsters gave rise to invasive growth of tumors with metastasis to the brain and eyes. These findings provide definitive evidence for a B-cell origin of the brain lymphoma in this case.

Adult↗
PubMed1982

S-100 protein in human glial tumours. Qualitative and quantitative studies.

The authors studied a total of 48 human glial tumours for S-100 protein, an extremely acidic, protein specific to the nervous system, by immunohistochemistry and by micro-complement fixation assay in order to evaluate S-100 protein as an index for malignancy of glial tumours. All of 48 glial tumours analyzed in the present study demonstrated variable amounts of S-100 protein which might serve as a biochemical cell marker for glial tumours. The mean value of S-100 protein content in 3 ependymomas is higher than those of 19 low-grade (grades I, II) astrocytomas and 26 high-grade (grades III, IV) astrocytomas, being lowest in the latter. A statistically significant (P less than 0.001) difference in S-100 protein levels between low- and high-grade astrocytomas is observed, but not for ependymoma. At present, however, no correlation can be found between S-100 protein content of a tumor and the patient's survival time. Immunoperoxidase staining for S-100 protein in high-grade astrocytomas is generally weak in intensity and heterogeneous throughout the section, whereas that in low-grade astrocytomas and ependymomas is relatively strong and homogeneous, indicating that high-grade astrocytomas consist of a more heterogeneous population of tumour cells in terms of S-100 protein. These results show that the investigation of S-100 protein in a glial tumor is valuable to a certain extent in assessing the degree of differentiation or malignancy of the tumour.

Adolescent↗