Search PubMed⌕ Search

Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 811 records · Page 45Linked to original sources
PubMed1981

Contribution of kinesthesia on human visuomotor elbow tracking movements.

The role of peripheral information in smooth motor performance was analyzed in normal subjects and patients with deep sensory disturbance by the modified visually guided tracking method. The subject's task was to make the control cursor match the slowly moving target by elbow flexion movement. Performance of normal subjects was scarcely affected, but that of the patients was deteriorated by the withdrawal of the visual cue for handle movement. It is suggested that afferent information from the moving limb plays an important role in smooth and accurate tracking movements.

Adult↗
PubMed1981

Glia maturation factor in bovine brain: partial purification and physicochemical characterization.

Glia maturation factor (GMF) is partially purified from bovine brains by the following procedure: extraction at physiologic pH, dialysis and freeze-drying of the extract, ethanol washing of the dried powder and re-extraction of the ethanol-washed residue with Tris-buffered saline, ion-exchange chromatography with DEAE Sephadex and molecular sieving with Bio-gel P-200. The partially purified protein has an apparent molecular weight of 23,000 and an isoelectric point of 4.75, and retains both morphological transforming and mitogenic activities when tested on glioblasts. Both activities are susceptible to protease digestion and heat inactivation. The procedure results in a 400-fold purification of the morphological activity and a 1400-fold purification of the mitogenic activity. Both activities are detectable when GMF is used in nanogram quantities. The possibility that both functions are expressions of the same factor and the possible role of GMF in the differential or sequential stimulation of cell growth and maturation are discussed.

Animals↗
PubMed1981

Ascorbic acid inhibition of Na,K-adenosine triphosphatase of rat forebrain without peroxidation of membrane lipids.

Using reagents and membrane preparations from which contamination had been carefully removed, we found that ascorbic acid inhibited rat brain Na,K-ATPase without causing lipid peroxidation, unlike the conventional belief; the inhibition was prevented by catecholamines and EGTA. Ascorbic acid radicals, instead of active oxygen, may play a role in the inhibition.

Adenosine Triphosphate↗
PubMed1981

Biological effects of bovine glia maturation factor on glial cells in culture.

Optimal bioassay conditions for bovine glia maturation factor (GMF) were determined among glial cells from normal glioblasts to glioma cells. Rat glioblasts 4-8 days after subculture show the highest response t GMF with regard to morphological transformation and mitogenic activity. Bovine GMF enhances DNA synthesis of rat glioblasts at 12 h after stimulation; maximum incorporation of [methyl-3H]thymidine was detected at 18 h. GMF increases twofold the saturation density of rat glioblasts but does not alter that of C6 astrocytoma cells. The apparent inhibition of mitogenic activity of high doses of GMF is seen in both normal and malignant glial cells.

Animals↗
PubMed1981

Traumatic primary intraventricular hemorrhage.

Two patients with primary intraventricular hemorrhage following mild head injury are presented. Both patients experienced a rapid loss of consciousness after a lucid interval following the head injury. Conray ventriculography or computerized tomography revealed intraventricular hematoma originating in the third ventricle and causing an obstructive hydrocephalus. Both patients made good recoveries promptly after ventricular drainage.

Adult↗
PubMed1981

Glial cell growth-promoting factor in astrocytoma (C6) cell extracts.

The presence of glia maturation factor (GMF)-like activity was demonstrated in rat astrocytoma cells (C6 cells). The extracts of C6 cells enhanced the DNA synthesis of cultured glioblasts 3-fold at the maximum, inducing such morphological changes as extrusion of processes. C6 cells also showed a proliferative response to the extracts, though the responsiveness in terms of effective concentration of C6 extracts was about a half of the glioblast responsiveness. The extracts lowered growth rate of neuroblastoma cells and especially decreased their DNA synthesis without a morphological differentiation.

Animals↗
PubMed1981

Brain tumors in tuberous sclerosis. Report of 4 cases.

We report on 4 cases of brain tumors associated with tuberous sclerosis. In each case the tumor was in the region of Monro's foramen and was associated with ventricular dilatation. Computer tomography scans, which were performed in 3 cases, revealed well-circumscribed high-density masses which were markedly enhanced by contrast medium. 3 patients underwent craniotomy. Total extirpation was performed in 2 patients. Both of them are doing well postoperatively. However, 1 patients whose tumor had been partially resected died of recurrence 6 years after surgery. The pathology of three tumors was different in each case: plump cell astrocytoma, hemangioma and astroblastoma.

Adolescent↗
PubMed1981

Comparison of the responses in the nomifensine test with hyperprolactinemia due to prolactin-secreting pituitary tumors and nonprolactin-secreting hypothalamic tumors.

It has recently been proposed that nomifensine (Nom) administration discriminates those patients with PRL-secreting pituitary tumors from those who have hyperprolactinemia due to other causes. In the present study, this test was performed on 12 presumed functional hyperprolactinemic subjects, 9 patients with surgically proved PRL-secreting pituitary adenoma (6 microadenoma and 3 macroadenoma), and 7 patients with surgically proved non-PRL-secreting hypothalamic tumors (3 craniopharyngioma, 3 suprasellar germinoma, and 1 suprasellar ependymoma). The Nom test suppressed the plasma PRL level to below 60% of the basal level in all 12 women with presumed functional hyperprolactinemia, but did not alter plasma PRL levels in the patients with PRL-secreting pituitary adenoma or hypothalamic tumor. This evidence confirms that the test is, at least in part, able to discriminate those individuals with PRL-secreting pituitary adenoma from those without, regardless of the size of the tumor. However, the test is not capable of distinguishing between hyperprolactinemia due to PRL-secreting pituitary tumors and that due to non-PRL-secreting hypothalamic tumors. A lack of response to Nom is not necessarily due to the presence of a PRL-secreting tumor, and may be related to dysfunction to the hypothalamic-pituitary system.

Adenoma↗
PubMed1981

Changes in somatostatin release from perfused pancreas of streptozotocin-induced diabetic rats.

To clarify the mechanism of an increased response of diabetic D-cells to arginine, we studied the changes in responsiveness of pancreatic D-cell to this agent with the passage of time after the onset of diabetes and the effect of chronic insulin substitution on the altered D-cell function utilizing the perfused pancreas of streptozotocin diabetic rats. The magnitude of somatostatin (SRIF) response to arginine (10 mM) was progressively increased with the duration of diabetes. The integrated response of SRIF during a 20 min period of an arginine infusion one week after the injection of streptozotocin was not different from that in the normals, but it was increased by 240% at 8 weeks and by 390% at 15 weeks. The exaggerated pancreatic SRIF release observed in 8 week diabetic rats was partially ameliorated with the daily insulin replacement (15.0 +/- 1.0 units/kg of B.W.). This was accompanied by a partial recovery from growth failure. The integrated amount of SRIF secreted during an arginine-stimulated period (20 min) was inversely correlated with an increase in body weight during an 8 week period (r = -0.741, p less than 0.001). From these results, it might be concluded that the alteration in diabetic D-cell function may be related to the metabolic and hormonal abnormalities of diabetes, rather than insulin deficiency itself.

Animals↗
PubMed1981

Study on the absorption and protein binding of carbaryl, dieldrin and paraquat in rats fed on protein diet.

Carbaryl was well absorbed from the small intestine of rats. In the cytosol fraction of intestinal mucosa, it was bound to a smallmolecular component (M. W. 2,200 daltons). In serum, carbaryl was bound mainly to albumin and partly to globulins. Dieldrin was slowly absorbed from small intestine. The peak of dieldrin concentration in blood was observed 2.5 hr after the administration. Binding of dieldrin to mucosal protein in cytosol was not detectable. In serum, dieldrin was bound to lipoproteins, globulins and partly to albumin. Absorption of paraquat from the small intestine was more rapid than that of dieldrin in situ study. However, in vivo study, the absorption of paraquat was the lowest among these three chemicals. In the cytosol fraction of intestinal mucosa, paraquat was bound to a small-molecular component (M. W. 3,100 daltons). In serum, it was present in unbound fraction. In the comparative studies with protein diets, absorption of paraquat from small intestine in situ was higher in low protein diet rats than that in high protein diet rats. However, difference in absorption in vitro and in histopathological study was not noted between low protein diet rats and high protein diet rats.

Animals↗
PubMed1980

Preliminary evaluation of intratumoral injection of a Streptococcus pyrogenes preparation in patients with malignant brain tumors.

Thirteen patients with malignant brain tumors, 12 anaplastic gliomas and one metastatic tumor, received repeated intratumoral injections of an immunopotentiator, Picibanil, prepared from streptococcus pyogenes. All patients tolerated this therapy; morbidity rates were acceptable. Significant tumor regression was noted on computerized tomography scanning for 6 of 12 patients for whom scanning was performed. Histologic examination of the post-therapy specimens obtained from 8 patients revealed that inflammatory reactions were evoked in all of the tumors, although the extent of inflammatory changes varied from patient to patient and mostly was localized to an area surrounding the intratumoral tubes.

Adjuvants, Immunologic↗