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Biomedical subjects

Y Katayama

Publications and source records attributed to Y Katayama.

At least 829 records · Page 46Linked to original sources
PubMed1979

Effect of feeding amino acid mixtures on lipid transport from rat liver as measured by liver perfusion.

The present study examined lipid transport from the liver by application of a perfusion technique in situ in rats fed diets consisting of a low level Wheat- or Rice- or Miyazaki-pattern amino acid mixture. The net release of hepatic lipids was directly estimated from analysis of the perfusate continuously circulated through the liver. The net release of triacylglycerol from the liver into the perfusate was much more severely inhibited in the Wheat-pattern diet group, and more depressed in the Rice-pattern diet group than in the control group, and slightly reduced in the Miyazaki-pattern diet group compared with the control. For serum lipoproteins fractionated by the Quick-Disc electrophoresis method, there was a significant decrease in the serum pre-beta lipoprotein fraction in all the rats of the Wheat-, Rice- and Miyazaki-pattern diet groups compared with the control. These observations provide firm support for the hypothesis that in rats given diets consisting of a low level of the Wheat-, Rice- and Miyazaki-pattern amino acid mixture, fatty liver may be produced mainly by an impaired transport of triacylglycerols from the liver.

Amino Acids↗
PubMed1979

[Contingent negative variation in patients with severe closed head injury--its diagnostic value as a quantitative evaluating method for certain aspect of posttraumatic syndrome (author's transl)].

CNVs were studied in 48 subjects with closed head injury followed by posttraumatic amnesia over than 7 days. Electrical motor-threshold stimulation of the median nerve or subjectively painful stimulation of the fingertip was used for imperative stimulus. An amplitude of CNV and its enhancement by painful imperative stimulus were measured and compared with those obtained from 34 normal subjects. In subacute stage within 3 months after the head injury, correlation between CNV abnormalities and an existence of some noticeable psychiatric disorders was found. In many of the subjects with CNV abnormalities, diffuse slow wave activities were observed in the background EEG, so that it was supposed that CNV abnormalities in subacute stage might reflect diffuse cerebral dysfunction and decreased vigilance. Any statistically significant correlation of CNV abnormalities to an existence of psychiatric disabilities, low score in WAIS and background EEG patterns could not be found in chronic stage 12 months after head injury. However, suppressed CNV was observed in all of 4 subjects who presented generalized epileptic patterns in the background EEG. Many of the subjects with suppressed CNV also showed a small effect of painful imperative stimulus on its amplitude. Statistically significant correlation between CNV abnormalities and work capacity was found. From these findings, together with previous observations (Tsubokawa et al. 19,36,40,44)), it is concluded that the measurement of the CNV is inimitable examination to evaluate certain psychiatric disability which is apt to be overlooked but, in fact, concerned intimately to the work capacity.

Adolescent↗
PubMed1978

Application of high-powered microwave irradiation for acetylcholine analysis in mouse brain.

Acetylcholine (ACh) levels in whole brains or discrete areas of mice brains were measured after sacrificing by decapitation, conventional or high-powered microwave irradiation. ACh levels in mice brains varied according to the time required to inactivate the enzymes. ACh levels after high-powered microwave irradiation for a shorter time were significantly higher than those after conventional irradiation.

Acetylcholine↗
PubMed1978

Characteristics of Thiobacillus thioparus and its thiocyanate assimilation.

Thiocyanate-assimilatig bacterium, TK 21, was isolated from activated sludge used for the treatment of thiocyanate contained in coke-oven liquor. This organism oxidized thiosulfate and elemental sulfur, causing a decrease of pH of the medium. These facts indicated that it belongs to the genus Thiobacillus. Potassium thiocyanate (0.5 g/l) was completely assimilated during 60 h. Thiosulfate inhibited the assimilation of thiocyanate but elemental sulfur did not. This bacterium did not evolve cyanide as its oxidation product after the decomposition of thiocyanate. The isoalted bacterium was identified as Thiobacillus thioparus. Examination of the composition of cellular fatty acid of three strains of T. thioparus showed that they prossessed 3-hydroxy fatty acid of C10 and C12; saturated straight chains of C10, C12, C15, C16, C17, and C18; monounsaturated straight chains of C16 and C18; and cyclopropane acid of C17.

Fatty Acids↗
PubMed1978

Cholesterol from serum and cholesterol-phospholipid dispersions by isolated rat hepatocytes in vitro.

The rate of uptake of cholesterol by isolated rat hepatocytes from incubation medium containing rat serum was low and did not increase by the prolongation of incubation time up to 2 hr at 4 degree. However, the hepatocytes took up cholesterol very actively at 37.5 degree from serum as well as from a cholesterol-phospholipid dispersion. The cholesterol uptake by the cells from liposomes increased linearly with the increase of the cholesterol concentration of liposomes, but that from serum reached the maximum at about 1.5 mu mol/ml cholesterol and remained at a plateau level at higher concentrations. Cholesterol was transfered from every class of serum lipoprotein, although the uptake ratio was the highest from the LDL fraction. As the lipoprotein concentration was increased, the uptake ratio decreased in the same way as that observed in the incubation with whole serum. The concentration of labeled ester cholesterol in the medium decreased more rapidly than free cholesterol during incubation. Cholesterol in the hepatocytes, however, was found mainly as the free form, suggesting that ester cholesterol taken up by the cells was rapidly hydrolyzed. Cholesterol accumulation was not observed in hepatocytes incubated in medium containing serum, but their cholesterol content was increased after the incubation in medium with liposomes of high cholesterol concentration. Therefore the uptake of cholesterol by hepatocytes from serum lipoproteins is probably carried out by a process different from that of uptake from liposomes which is considered to be a physicochemical phenomenon.

Animals↗
PubMed1977

[Modulating mechanism of the dorsal column stimulation for pain relief (author's transl)].

The neural mechanism of the modulating effects of spinal cord stimulation upon intractable pain was studied in cats under local anaesthesia. The electrical activity at the centre median nucleus of the thalamus (CEM), which responded to noxious stimuli and was inhibited by nitrous oxide inhalation, was recorded as an indicator of the degree of pain sensation. The suppressed effect upon the evoked potential responding to sciatic stimulation (1 Hz) was recorded during and after train stimulation of various parts of the spinal cord by means of silver ball bipolar electrode. Whenever inhibitory modulating effect upon CEM response was observed by spinal cord stimulation, the bilateral dorsal tractotomy cranial, caudal or both to the stimulating point in order to examine the influence upon the CEM potential. The results are as follows: 1) The CEM evoked potential responding to sciatic stimulation is inhibited by about 30-45% of its amplitude by dorsal column stimulation. This effect corresponds to the inhibitory effect by 75% N2O gas inhalation. Upon dorsal column stimulation, the intraspinal electrical activity is found in the central gray matter the antero-lateral quandrants of the spinal cord as well as the dorsal column. 2) Following lateral or anterior column stimulation as well as dorsal column stimulation, the CEM evoked potential responding to sciatic stimulation is inhibited by about 50% of its amplitude. 3) Following bilateral dorsal tractotomy cranial, caudal or both to the stimulating point, the CEM evoked potentials responding to sciatic stimulation are inhibited by dorsal column stimulation. According to the experimental results, it may be concluded that the inhibitory modulating mechanism by dorsal column stimulation for pain relief is not only mediated through the dorsal column, but also through other ascending spinal pathways.

Animals↗
PubMed1976

Feed-back control of cholesterol synthesis in partially hepatectomized rats.

Partial hepatectomy caused a marked stimulation of cholesterol and fatty acid syntheses without affecting serum total cholesterol, total phospholipid and triacylglycerol concentrations of rats so far examined 48 h after the operation. Serum free cholesterol level, however, was increased by the treatment and the ratio of lysophosphatidylcholine to phosphatidylcholine was concomitantly decreased, suggesting the impairment of serum lecithin: cholesterol acyltransferase activity. The lipid content in the liver, especially triacylglycerol and ester cholesterol, was increased markedly by the operation. Feeding of a high cholesterol diet which elevated serum cholesterol and phospholipid levels to the partially hepatectomized rats, accelerated the accumulation of hepatic triacylglycerol and ester cholesterol by the partial hepatectomy. The weight of the regenerating liver was not influenced by cholesterol feeding, which suggested that cholesterol feeding did not inhibit the regeneration mechanism of the liver. The increase of cholesterol synthesis after partial hepatectomy was inhibited by cholesterol feeding. Therefore, it is conceivable that the negative feed-back control of cholesterol synthesis is induced by cholesterol feeding under the stimulated cell divisions of the liver after partial hepatectomy. It is suggested from the present data that a large amount of the cholesterol which is necessary for cell growth can be taken up from serum, when serum cholesterol concentration is high.

Acetates↗