Search PubMed⌕ Search

Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 703 records · Page 39Linked to original sources
PubMed1986

[Study of cerebral blood flow in patients with cerebral infarction by 133Xe inhalation method--comparison between affected and unaffected hemispheres, and sequential changes].

Cerebral blood flow in both hemispheres was studied by the 133Xe inhalation method in 49 patients with cerebral infarction in the unilateral hemisphere. They were classified into three groups by computed tomographic findings as follows; relatively large low density lesion including the cerebral cortex and subcortex (cortical: C group), relatively large low density lesion including the subcortical white matter and basal ganglia (large subcortical: L group), and small low density lesion including the subcortical white matter (small subcortical: S group), respectively. Mean cerebral blood flow (mCBF) in the affected hemispheres was markedly low in C group, moderately low in L group, and slightly low in S group, in all of the examinations. Several cases in C and L groups revealed remarkable changes of mCBF less than one month after the onset. MCBF in both hemispheres was lower in C group than in L and S groups less than one week after the onset. Seven to twelve weeks after the onset, mCBF in the affected hemisphere was lower in C and L groups than in S group, and than in the unaffected hemisphere of C and L groups. There was no difference between mCBF in the affected hemisphere and that in the unaffected hemisphere in most of S group. Sequential changes of mCBF in both hemispheres were divided into seven types in 27 cases, who were examined first less than one week and repeatedly then. However, the sequential changes were classified roughly into two patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1985

Reciprocal inhibition upon initiation of voluntary movement.

Phasic changes in reciprocal inhibition of the soleus motoneurons upon initiation of active ankle dorsiflexion was investigated in normal man. H-reflex and reaction time methods were combined. Two phases of reciprocal inhibition were observed. The first inhibition appeared almost simultaneously with the activity of agonist EMG but was so weak as to be cancelled with a strong test stimulus or a slight stretch of the test muscle. The second inhibition developed 100 ms after EMG onset, in the early stage of dynamic contraction, and was strong. These inhibitions increased as the voluntary effort was strengthened. The neural mechanism of these inhibitions is discussed.

Adult↗
PubMed1985

Computed tomographic and histopathological studies of pontine glioma.

Correlative study of computed tomography (CT) and pathologic findings was performed in eight cases of pontine glioma. All patients except one had chemotherapy and radiotherapy, with no surgical intervention. On initial CT scans, all patients had hypodense lesions in part or the whole of the pons, and there was evidence of mass effect. Four of eight cases showed contrast enhancement. After chemotherapy and radiotherapy, swelling of the pons and the width of the hypodense areas decreased. The hypodense areas sometimes became isodense in correlation with clinical amelioration. After several months of remission in responding cases, ring-enhanced lesions reappeared at the primary site, together with recurrent neurological signs. Pathological study postmortem was focused on the histological counterparts of the CT findings of central and perifocal hypodense areas and contrast enhancement. In six of seven treated cases, the central hypodense area surrounded by ring enhancement was shown to be coagulation necrosis. Higher cellularity and hypervascularity with glomeruluslike structures of small vessels were generally observed in enhanced areas. The areas diffusely infiltrated by tumor cells, but not enhanced in CT scans, had few abnormal vessels. Tumor cells were seen not only in hypodense areas around the enhanced portion but also in areas far beyond the enhanced portion. Exophytic expansion of tumor was observed in two cases on postmortem examination. One of these was detected by CT scans before death.

Astrocytoma↗
PubMed1985

Cerebral hemodynamics in patients with moyamoya disease. A study of regional cerebral blood flow by the 133Xe inhalation method.

Regional cerebral blood flow was measured by the 133Xe inhalation method in 20 young patients with moyamoya disease and five young healthy volunteers. Most patients showed low values of mean hemispheric blood flow in both hemispheres. Regional cerebral blood flow was at a low value in the upper frontal region and at an almost average value in the posterotemporal and occipital regions, which was different from the "hyperfrontal" pattern in healthy volunteers. Regional cerebral blood flow was reduced evenly by hyperventilation. By 5% CO2 inhalation, regional cerebral blood flow was increased in the temporooccipital regions and was nearly unchanged or decreased in the frontal region.

Adolescent↗
PubMed1985

Hyperthyroidism caused by a pituitary thyrotrophin-secreting tumour with excessive secretion of thyrotrophin-releasing hormone and subsequently followed by Graves' disease in a middle-aged woman.

A 46-year-old woman had signs of thyrotoxicosis and galactorrhoea. Serum immunoreactive TSH and its alpha-subunit increased in the presence of high serum triiodothyronine (T3), thyroxine (T4), and free T4 concentrations, whereas beta-subunit TSH was undetectable. Exogenous TRH failed to increase serum TSH. Serum TSH was markedly suppressed by glucocorticoid, but was increased by antithyroid drug. L-Dopa or bromocriptine partially suppressed, but nomifensine had no influence on serum TSH. Serum prolactin (Prl) was above normal and markedly increased by TRH, but depressed by bromocriptine and not suppressed by nomifensine. Plasma TRH was normal in the hyperthyroid state, but was increased by glucocorticoid and antithyroid drug. Excess thyroid hormone depressed plasma TRH concentrations. Basal serum GH levels were constantly low. Transsphenoidal removal of the tumour normalized serum hormones (T3, T4 free T4, TSH, alpha-subunit and Prl), and eradicated the clinical signs of hyperthyroidism and galactorrhoea. Histological study of the tumour tissue demonstrated both thyrotrophes and somatotrophes. A reciprocal relationship between serum TSH and T4 concentrations shifted to a higher level before but was normalized after removal of the tumour. Ten months later, the clinical signs of thyrotoxicosis and the increase in serum thyroid hormone recurred without a concomitant increase in serum TSH and its alpha-subunit. Thyroidal auto-antibodies were slightly positive, but thyrotrophin-binding inhibitor immunoglobulin (TBII) was negative. Administration of antithyroid drug produced a euthyroid state, but 3 years later, discontinuation of the treatment resulted in recurrent hyperthyroidism without suppressed plasma TRH and with no evidence of regrowth of the pituitary tumour. It is suggested that the patient initially had hyperthyroidism owing to excessive TSH secretion from the tumour caused by abnormal TRH secretion, and subsequently had hyperthyroidism owing to Graves' disease.

Adenoma↗
PubMed1985

Peritoneoscopy of alcoholic liver cirrhosis in comparison with non-alcoholic liver cirrhosis.

Peritoneoscopic findings of 39 patients with alcoholic liver cirrhosis (ALC) were compared with those of 95 patients with non-alcoholic liver cirrhosis (NALC). They were selected from 245 patients with liver cirrhosis subjected to peritoneoscopy in the 7 year period from 1975 to 1981. Out of the 95 NALC patients, 24 had hepatitis B surface antigen. The ALC patients had nodules which varied in size (61%), large depressions (69%), and a markedly rounded edge of the liver (33%) more often than NALC patients (18, 43 and 3%, respectively). Nodularity differed between the right and left lobes in ALC (41%) more often than in NALC (16%). Interstitial reddish markings and patchy nodules were, however, more frequent in NALC (51 and 28%, respectively) than in ALC (8 and 5%, respectively). Lymphatic vesicles were observed both in ALC (85%) and NALC (78%). In conclusion, the peritoneoscopic features which suggested ALC were the coexistence of nodules of various sizes, large depressions and a markedly dull edge of the liver. Interstitial reddish markings and patchy nodules were more indicative of NALC than ALC.

Adult↗
PubMed1985

Comparison of estimation methods of liver maximum removal rate of indocyanine green.

Three linear plots by which the liver's maximum removal rate (Rmax) of indocyanine green (ICG) and the Michaelis constant (Km) can be calculated were compared in a microcomputer simulation study. The widely-used Lineweaver-Burk plot (1/V vs. 1/S; V, ICG initial removal rate (mg/kg/min); S, ICG loading dose (mg/kg] presented the greatest bias and variance. There was no remarkable difference in bias between the S/V vs. S plot and the V vs. V/S plot, but the latter possessed a smaller variance. Therefore, the V vs. V/S plot was considered the best for estimating Rmax. The best combination of three ICG loading doses was 0.5, 2, and 5 mg/kg. This combination was selected by comparison of the Rmax estimated from three points with that estimated from six points (0.5, 1, 2, 3, 4 and 5 mg/kg).

Humans↗
PubMed1985

Comparative diagnosis of alcoholic liver diseases by multivariate and histological analysis.

Sixty-seven cases of alcoholic liver disease were histologically classified into 4 groups: alcoholic liver cirrhosis (ALC), alcoholic hepatitis (AH), alcoholic liver fibrosis (ALF) and alcoholic fatty liver (AFL). They were statistically reclassified by the likelihood method using age, total alcohol intake, hepatomegaly and 12 liver function tests. A score table for likely diagnosis was constructed from the incidences of each range. The cases were re-evaluated using the score table, with an overall correct diagnosis rate of 73%. The best combination of 5 parameters included the indocyanine green plasma disappearance rate, total alcohol intake, cholesterol, choline esterase and glutamic oxaloacetic transaminase/glutamic pyruvic transaminase ratio. A correct diagnosis rate of 75% was attained using these 5 parameters, and 94% of patients were correctly diagnosed by the first or the second likelihood diagnosis. Differential diagnosis of alcoholic liver diseases was easily and confidently obtained with the likelihood score table.

Adult↗
PubMed1985

Stimulation and inhibition of DNA synthesis and cell growth by paraquat in cultured cells.

Paraquat, a popular herbicide, is known to be very toxic to man and animals. Using cultured mammalian cells (human embryo lung cell, R-66), the effect of paraquat has been studied. With autoradiography, stimulation of DNA synthesis was observed when the cells were exposed to 0.08 or 0.4 microM of paraquat; however, DNA synthesis was inhibited with 40 microM of paraquat. To determine cell growth rate, accumulation of mitotic cells was determined after addition of colcemid (0.2 microgram/ml) into the culture medium. The ratios of mitotic cells observed were proportional to the level of DNA synthesis. And the stimulation and inhibition of cell growth were observed even after washing off paraquat from media.

Autoradiography↗
PubMed1985

[Clinicoimmunological values of measurement of IgG-Fc receptor positive T cells in the patients with malignant brain tumors].

It has recently been shown that human T-cell subpopulation can be identified functionally via surface receptors for Fc fragment of immunoglobulins. We detected peripheral blood T-cells bearing the Fc receptor for IgG molecules (T gamma cell) in patients with brain tumors who manifested a variety of immunological abnormalities. We also analyzed immunological values of T gamma cells which were thought to be suppressor and/or a part of killer T cells, comparing with other immunological parameters. The percentage of T gamma cells was significantly higher in patients with malignant brain tumors than in normal controls (6.54 +/- 1.6%). The values of T gamma cells in patients with glioma, metastatic brain tumor, benign brain tumor were 15.4 +/- 4.8%, 14.9 +/- 3.2%, and 8.1 +/- 3.7%, respectively. In the patients with glioma, the values increased in the uncontrolled group compared with the well-controlled group. Furthermore, the values were decreased by surgical removal of the tumor. On immunological study of T gamma cells in the patients with glioma, there was a definite correlation between the values of T gamma cells and ADCC activity. Furthermore, the T gamma cells in the patients showed higher ADCC activity than in normal controls. The values of T gamma cells also correlated with blastogenesis of the peripheral blood lymphocytes by PHA (r = -0.742, p less than 0.001) and Con A (r = -0.662, p less than 0.001). These results suggest that T gamma cells are playing two important roles in patients with glioma such as suppressor function and ADCC activity, and that these cells may change according to the tumor growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody-Dependent Cell Cytotoxicity↗
PubMed1985

[Evaluation of ACNU alone and combined with tegafur as additions to radiotherapy of the treatment of malignant gliomas--a cooperative clinical trial].

Controlled, prospective, randomized studies were performed to evaluate the effects of 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3- (2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) and ACNU plus tegafur as additions to radiotherapy for the treatment of malignant gliomas. In the first trial, 105 patients with glioblastoma or anaplastic astrocytoma were randomly divided into two groups after surgery and received radiotherapy (RT, 40 to 60 Gy to the whole brain), or radiotherapy plus concomitant chemotherapy with ACNU (100 mg/m2 on day 1 and 42). Effects of the treatment were compared in 82 evaluable patients from results of CT scans taken before and one month after the completion of radiotherapy. The regression rates more than 50% of the tumor size were observed in 15.0% of patients treated with RT alone and in 47.6% of patients treated with RT plus ACNU. The difference was statistically significant (p less than 0.005). In the second trial, 87 patients were randomly divided into two groups and received RT plus ACNU, or RT plus combined chemotherapy with ACNU and tegafur (400 mg/m2, daily for 8 weeks). Sixty-nine patients were within the valid study group. The regression rates more than 50% of the tumor size were observed in 34.2% of patients treated with RT plus ACNU: and in 41.2% treated with RT, ACNU plus tegafur. No statistical difference was noted in the response rate between the groups. These results indicate that ACNU is an effective agent in conjunction with radiotherapy for patients with malignant gliomas, and that tegafur does not enhance the effectiveness of ACNU.

Adolescent↗