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Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 739 records · Page 41Linked to original sources
PubMed1984

The absence of differentiation-promoting response of astroglioma cells to glia maturation factor.

The effects of glia maturation factor (GMF) on cell proliferation and differentiation were investigated with 3 astroglioma cells (GE-12, C6, and GA-1), Schwannoma-like cells (354A), and mixed glioma cells (LRM-55). In the exponentially growing phase the growth rates of all glioma cells were enhanced by GMF regardless of the presence or absence of serum, but the factor failed to make the saturation density surpass the control level observed in the medium without GMF even in the chemically defined medium (N2 medium). GMF markedly lowered the saturation density of Schwannoma-like cells in N2 medium. Although GMF increased the intracellular content of S-100 protein 10-fold and 2',3'-cyclic nucleotide phosphohydrolase activity 1.5-fold in Schwannoma-like cells, GMF conversely decreased the S-100 contents and glycerol phosphate dehydrogenase activity in astroglioma cells. All the astroglioma cells secreted into the culture medium large quantities of a growth-promoting factor(s) which had similar chemical properties to those of GMF and stimulated the proliferation of normal glioblasts; but Schwannoma-like cells did not, although they produced a small amount of such a factor(s). These findings imply that astroglioma cells are deprived of the differentiation-promoting response to GMF while Schwannoma-like cells still preserve the response in addition to the proliferative response to GMF.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1984

Changes in reciprocal Ia inhibition during voluntary contraction in man.

Reciprocal Ia inhibition from ankle flexors to extensors was studied during voluntary tonic isometric dorsiflexion and plantar flexion in five normal subjects. The Ia inhibition was examined as the short-latency suppression of the soleus H-reflexes by stimulation of the low-threshold afferents in the common peroneal nerve (Mizuno et al. 1971). At rest, weak Ia inhibition was demonstrated in four subjects out of five, the maximal amount being 14.1 +/- 5.0% suppression of the control H-reflex. The absolute amount of inhibition, which was calculated by subtracting the mean size of the conditioned H-reflex from that of the control H-reflex and expressed as a percentage of the maximal M-response, increased during ankle dorsiflexion, and decreased or disappeared during plantar flexion in parallel with the amount of contraction. The neural mechanisms for facilitation of the Ia inhibitory pathway during dorsiflexion were considered to support the hypothesis of "alpha-gamma-linkage in reciprocal inhibition", i.e. combined facilitatory effects on the Ia inhibitory interneuron from the supraspinal centers directly and indirectly via the gamma motoneuron--Ia afferent route. The mechanism for inhibition of the pathway during plantar flexion was considered to be inhibition of the Ia interneuron of the flexor side by Ia interneuron of antagonist extensors. A quantitative aspect of activity in the reciprocal Ia inhibitory pathway on the performance of voluntary movement is revealed in this study.

Adult↗
PubMed1984

Visualization of lactoperoxidase binding to microtubule and tubulin.

The binding of lactoperoxidase to microtubules and tubulin was shown in both electron micrography and polyacrylamide gel electrophoresis by tracing the enzymatic activity of lactoperoxidase. Lactoperoxidase bound to purified microtubules appeared to distribute evenly on the surface without forming special structures. Both alpha and beta-tubulin separated by sodium dodecylsulfate-polyacrylamide gel electrophoresis bound lactoperoxidase, and could be detected by the use of lactoperoxidase reaction. Electrophoretic study revealed that the interaction between lactoperoxidase and tubulin were not strictly specific and a variety of proteins other than alpha- and beta-tubulin, including actin and neurofilament subunits, bound lactoperoxidase.

Animals↗
PubMed1984

Analysis of cerebellar motor disorders by visually guided elbow tracking movement.

Motor control was analysed by a visuomotor tracking movement using elbow flexion both in patients with cerebellar ataxia and in normal controls. A TV screen was divided into upper and lower halves, in each of which a vertical strip was displayed. The upper strip (T, target) was moved horizontally from the centre of the screen to the left or right by ramp voltage. The lower strip (D, displacement of the handle) was moved in proportion to angular displacement of the handle by a potentiometer coupled to the handle axis. The subject, while sitting in front of the TV screen, had to make D match the movement of T by controlling the handle with his right arm. The range of T movement was 30 deg in terms of the handle's angular movement. T velocity was 7.5, 15 or 30 deg/s. The subjects were told the direction and velocity of T in advance. The process of tracking was divided into three phases (initial catch-up phase, middle pursuit phase, and terminal phase), in each of which the performance of cerebellar ataxia patients differed from that of the controls. The characteristic features of the ataxic cases were (1) prolongation of the reaction time, mainly due to the increase of premotor time; (2) difficulty in selecting an appropriate amplitude of initial peak velocity in proportion to the target velocity in the initial catch-up phase; (3) disruption of smooth continuous movement, namely, the saccadic pattern in the middle pursuit phase; (4) delay in the initiation of deceleration in the terminal phase; (5) difficulty in corrective adjustment in reaching the final target point; and (6) irregular EMG activity in the agonist muscles and/or cocontraction of the antagonistic muscles. Quantitative treatment of the second and third features, as exemplified in the relationship between initial error and initial peak velocity and in the ratio of the movement arrest period, respectively, was found to be helpful in the evaluation of disease severity. The significance of these findings is discussed and the role of the cerebellar system in the control of slow voluntary movement is stressed.

Adult↗
PubMed1984

CT findings of medulloblastoma.

Computed tomography (CT) of 11 patients with medulloblastoma was evaluated. 6 of them showed solid, nearly homogenous lesions and definite enhancement after infusion of contrast medium. However, 5 cases showed heterogenous mass lesions composed of the areas of low density and iso- or slightly high density which was attenuated by contrast enhancement. Histological examinations revealed that 2 cases had differentiated medulloblastomas, but the other 3 typical medulloblastomas. It should be reminded in the differential diagnosis of cerebellar tumors of pediatric patients that medulloblastoma can reveal heterogenous mass in CT scan.

Cerebellar Neoplasms↗
PubMed1984

Cytogenetic and functional studies of leukocytes with Pelger-Huët anomaly.

A cytogenetic study was undertaken in 15 cases of Pelger-Huët (P-H) anomaly in 3 families. An enlarged short arm of chromosome 22 (22p+) was found in 14 cases, but in these families 4 cases without P-H anomaly did not show 22p+ in the karyotype. In P-H anomaly, delayed skin hypersensitivity reactions, levels of serum IgG, IgM and IgA, lymphocyte subpopulations, and natural killer and antibody-dependent, cell-mediated cytotoxicity activities were within normal range. The level of serum IgE, mitogen responses in peripheral blood lymphocyte and plaque-forming cell counts were also within normal range with the exception of a case with atopic eczema. Enzymatic activities, nitroblue tetrazolium reduction and phagocytic capacities of neutrophils appeared normal. Abnormalities of neutrophils in cases of P-H anomaly, as compared with normal subjects, were also negative in examinations for chemotaxis and spontaneous migration under agarose and in a membrane filter.

Adolescent↗
PubMed1984

Effects of sake and bourbon on liver histopathology and function in rats.

Sake or bourbon (8g ethanol/kg body weight) was intragastrically administered to rats for 12 days. An equal dose of ethanol in water or an isocaloric glucose solution was administered to control groups. Food was withheld, but water freely provided. Neither mortality nor liver and body weights were different between the alcohol-treated groups. Glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were more elevated in the sake group than in the other groups. Additionally, liver fibrosis was more pronounced, and vacuole formation or steatosis was less in this group. These results suggest that sake is more fibrogenic. Some components other than ethanol, such as long-alkyl chain alcohols, may have been responsible for the differential histopathology.

Alcoholic Beverages↗
PubMed1984

Diagnosis of hepatocellular carcinoma in patients with liver cirrhosis using liver function assays.

Sex, age and 21 routine liver function assays were analyzed by stepwise selection and the best-of-all-possible-combinations method to identify a small group of assays valuable in establishing which liver cirrhosis (LC) patients have a high risk of hepatocellular carcinoma (HCC), when alpha-fetoprotein (AFP) is not elevated. Data was obtained from 115 HCC and 122 LC patients on admission. Tumor size correlated with AFP (0.73), alkaline phosphatase (ALP, 0.47), leucine aminopeptidase (LAP, 0.42), lactic dehydrogenase (LDH, 0.42), and the glutamic oxaloacetic transaminase (GOT)/glutamic pyruvic transaminase (GPT) ratio (GOT/GPT, 0.41). The mean of the correct diagnosis rates (CDR) of HCC and LC utilizing AFP as the sole parameter (89%) was markedly higher than those of the other parameters. The best-of-all-possible-combinations method presented a more powerful combination than stepwise selection. The best combination of 7 parameters (LAP, GOT/GPT, choline esterase, one-hour erythrocyte sedimentation rate, age, albumin/globulin ratio, and total bilirubin) presented a mean CDR of 80%, HCC CDR of 77%, and false positive rate of 18%. LC patients statistically diagnosed as having HCC by these 7 parameters are proposed as high risk patients. Fourteen (78%) of 18 HCC patients who were AFP-negative were statistically diagnosed. This analysis can be applied to LC patients to distinguish those that should be followed closely by imaging diagnostic techniques.

Adult↗
PubMed1984

Lack of uptake of indocyanine green and trypan blue by hepatocellular carcinoma.

Experimental hepatocellular carcinoma (HCC) in rats did not take up intravenously administered indocyanine green (ICG) and trypan blue, while surrounding tissue did. The lack of ICG uptake was also observed by peritoneoscopy in patients with HCC. The contrast between ICG-stained cirrhotic nodules and HCC tumors was intensified with infrared photography. Non-uptake of dyes by HCC cells may enable discrimination between tumors and normal cells.

Animals↗
PubMed1984

Effect of benzyl alcohol on adenosine triphosphatase, p-nitrophenylphosphatase and acetylcholinesterase in rat erythrocyte membrane.

The irreversible effect of benzyl alcohol on ATPase, p-nitrophenylphosphatase and acetylcholinesterase in the erythrocyte membrane of rats was demonstrated. The ATPase activity in the membranes was stimulated with 10 -70 mM benzyl alcohol and inhibited by concentrations greater than 80 mM. p-Nitrophenylphosphatase was gradually inhibited by concentrations of benzyl alcohol greater than 30 mM. The acetylcholinesterase activity was not affected by concentrations below 100 mM and strongly inhibited by concentrations of benzyl alcohol greater than 150 mM. With the uptake studies of 14C-labeled benzyl alcohol by membranes, the highest uptake was obtained in the presence of 200 mM of benzyl alcohol. And SDS-polyacrylamide gel electrophoresis showed a binding of benzyl alcohol to the major protein bands of the erythrocyte membrane. Therefore, stimulation of the ATPase activity appeared to be the result of an increase in ion uptake due to an increase in the fluidity of the membrane lipid by benzyl alcohol, and the inhibition of the enzymes may be the result of benzyl alcohol-induced denaturation of the membrane components. The difference in the observed inhibition patterns among ATPase, p-nitrophenylphosphatase and acetylcholinesterase may be related to the sensitivity of benzyl alcohol on those enzymes.

4-Nitrophenylphosphatase↗