Search PubMed⌕ Search

Biomedical subjects

A Okada

Publications and source records attributed to A Okada.

At least 415 records · Page 23Linked to original sources
PubMed1985

Influence of local vibration on plasma creatine phosphokinase (CPK) activity.

This study was designed to obtain basic information about the mechanism of the occurrence of muscular disorders after exposure to vibration. The hind legs of rats were exposed to acute and chronic local vibration at frequencies of 30, 60, 120, 240, 480, and 960 Hz with a constant acceleration of 50 m/sec2. The exposure time was four hours for acute, and four hours a day for two weeks continuously for chronic exposure. Blood was collected after exposure to measure plasma creatine phosphokinase (CPK) activity. In both exposure groups the activity of plasma CPK was significantly higher at 30, 60, 120, 240, and 480 Hz compared with the control group and was especially high at 30 Hz; there was no significant change at 960 Hz. As a result of an analysis of the CPK isoenzymes, the increase in plasma CPK activity was shown to be due to the activity of the plasma CPK-MM fraction, originating in the skeletal muscle. Plasma CPK activity showed a tendency to decrease gradually with the increase in vibration frequency during acute exposure but showed no such tendency during chronic exposure. There was no remarkable pathohistological change in muscle preparations from the hind legs, hence it was presumed that the increase in plasma CPK activity was caused not by the morphological changes of muscle but by other mechanisms, such as an increase in the permeability of the cell membrane.

Animals↗
PubMed1985

Effects of whole body vibration on biogenic amines in rat brain.

The effects of whole body vibration on the concentrations of noradrenaline (NA), dopamine (DA), and serotonin (5-HT) in the whole brain and brain regions of rats were investigated. Compared with control rats, vibration with 20 Hz frequency decreased the brain concentration of NA only when the acceleration (intensity) was increased to 5.0 G (p less than 0.05). The concentration of DA in the whole brain was not affected by acceleration. When acceleration was kept at a constant 0.4 G level and rats were exposed for the same 240 minute period to 5, 20, or 30 Hz vibration, neither NA nor DA concentrations changed in the whole brain. Regional changes in the concentration of biogenic amines in the brain of rats exposed to vibration of 20 Hz and 5.0 G showed few significant differences. Thus NA significantly decreased only in the hypothalamus (p less than 0.01), although in the hippocampus the decrease was nearly significant (p less than 0.10). The concentration of 5-HT significantly increased in the hypothalamus and cerebellum (p less than 0.05). DA tended to increase in the cortex and decrease in the striatum (p less than 0.10). These experiments seem to indicate that NA in the whole brain and especially in the hypothalamus is a better indicator of vibration exposure than 5-HT, and that NA is affected by the intensity but not by the frequency of vibration. NA and 5-HT in the hypothalamus change in the opposite direction. DA concentrations in the brain are basically unaffected by vibration.

Acceleration↗
PubMed1985

Reduced killer cell activity of lymphocytes from patients with asbestosis.

Immunological abnormalities in 30 patients with asbestosis were investigated by examining the cytoxicity of natural killer (NK) cells and antibody dependent cellular cytotoxicity by killer (K) cells from peripheral blood lymphocytes; the effects of interferon on NK activity was also examined. Fifteen men and 15 women (mean age 58; range 40-72) with asbestosis but who were free of complications such as tuberculosis, carcinoma, or steroid treatment were the subjects for study. There were nine cases of type 1, 19 cases of type 2, and two cases of type 3 disease as described in the ILO classification of pneumoconiosis. They were all textile workers with a mean duration of 18 years (3-40 years) since first exposure to chrysotile. Controls matched for age and sex were selected from a population without occupational exposure to asbestos. The activity of the NK and K cells in patients with asbestosis was significantly lower than in the control group, but the populations of NK and K cells in the peripheral blood lymphocytes were not significantly different in the two groups. An in vitro experiment showed that the increase in the cytotoxicity of the NK cell after treatment with interferon-alpha was significantly lower in the subjects than in the controls. These results indicate that one of the defence mechanisms in relation to cancer is deficient in patients with asbestosis.

Adult↗
PubMed1985

[Pharmacokinetic study of cefsulodin in children].

Cefsulodin (CFS), a cephem antibiotic, was administered to 26 children aged from 11 months to 11 years by intravenous injection or intravenous 1-hour drip infusion in doses of 15 and 50 mg/kg body weight to investigate serum and urinary concentrations. The following results were obtained. Serum concentration The serum concentrations of CFS at 5 minutes after intravenous injection of 15 and 50 mg/kg were 57.1 and 224.2 micrograms/ml, respectively. The biological half-lives (T 1/2 beta) were 1.28 and 1.12 hours. The serum concentration of CFS after intravenous 1-hour drip infusion reached a peak at the end of infusion, i.e. 29.9 micrograms/ml for 15 mg/kg and 121.9 micrograms/ml for 50 mg/kg, and T 1/2 beta were 1.22 hours for 15 mg/kg and 1.27 hours for 50 mg/kg. The AUC was proportional to the doses for both intravenous injection and intravenous drip infusion. The serum clearance was about twice the value in adults and the distribution volume was about 1.5 times as large. Urinary excretion The urinary excretion up to 6 hours after administration was: 69.0% for 15 mg/kg and 61.9% for 50 mg/kg in cases of intravenous injection, and 62.4% for 15 mg/kg and 71.1% for 50 mg/kg in cases of intravenous 1-hour drip infusion. The percent urinary excretion was similar to that in adults.

Cefsulodin↗
PubMed1984

Does total parenteral nutrition (TPN) really promote tumor growth? A morphometric study.

An experimental study was undertaken to evaluate the effects of total parenteral nutrition (TPN) on tumor growth in rats. Sato lung cancer was transplanted subcutaneously in male Donryu rats. Two weeks after inoculation, experimental animals were divided into three groups: Group I (5% G); Group II (21% G, 4% A.A; TPN) received intravenous infusion through cervical vein; Group III rats were maintained on a regular diet. All of the animals were killed on the eighth day. There was a significant increase in tumor volume and tumor weight in both G-II (7.3 +/- 3.9 cm3, 8.7 +/- 6.3 g) and G-III (7.4 +/- 4.6 cm3, 9.7 +/- 5.4 g), as compared with G-I (3.3 +/- 1.4 cm3, 3.7 +/- 1.9 g). In morphometric studies, an average area of tumor cell in G-II was 267 +/- 172 microns2, being significantly larger than in G-I (195 +/- 95 microns2) or G-III (185 +/- 93 microns2). The nuclear diameter of tumor cell was 9.9 +/- 2.2 microns in G-II, 9.2 +/- 1.9 micron in G-III, and 8.5 +/- 1.5 micron in G-I, respectively. Total water balance throughout the experimental period was +84.0 +/- 14.5 ml/100 g BW in G-II, +86.3 +/- 8.2 ml/100 g BW in G-III, and +44.8 +/- 22.5 ml/100 g body weight in G-I, respectively. Increased tumor volume and tumor weight found in G-II may not be due to hyperplasia of each tumor cell, but rather due possibly to water retention in tumor tissue.

Animals↗
PubMed1984

Effect of food intake on urinary excretions of histamine, N tau-methylhistamine, imidazole acetic acid and its conjugate(s) in humans and mice.

The urinary excretions by young healthy men of histamine and its metabolites, N tau-methylhistamine, imidazole acetic acid, and imidazole acetic acid conjugate(s), increased 1-3 h after food intake. The increase was seen even after the intake of konnyaku (mannan) as a protein-deficient food, suggesting that physical stimulation of the gastric mucosa by food is the main cause of histamine release. This suggestion was confirmed by the following findings in patients and mice. In patients with stomach diseases, gastrectomy resulted in decreases in the excretion of histamine and its metabolites in the urine, and patients subjected to intravenous hyperalimentation excreted less histamine and its metabolites in the urine than normal subjects. In mice, a correlation of histamine excretion with food intake was demonstrated experimentally. Namely, mice fed only during the night (21:00-0:00) showed increased excretions of histamine and its metabolites at 23:00-3:00, whereas those fed in the morning (9:00-12:00) showed increased excretions of those compounds at 11:00-15:00. All these results are consistent with the idea that urinary histamine and its metabolites mainly originate from the stomach.

Adult↗
PubMed1984

Serum interferon levels and natural killer cell activity in patients with asbestosis.

Natural killer cell activity and serum interferon levels were measured in 30 patients with asbestosis. The chest radiographs showed type 1 changes (ILO pneumoconiosis classification) in nine, type 2 changes in 19, and type 3 changes in two. Thirty control subjects matched for age, sex, and smoking habit were also studied. Patients with asbestosis had significantly higher serum interferon levels than the controls. There was no significant difference in natural killer cell activity between patients with asbestosis and normal controls.

Aged↗
PubMed1984

Heritability of erythrocyte Na+-Li+ countertransport in relation to essential hypertension.

The Na+-Li+ countertransport system in erythrocytes was investigated in patients with essential hypertension and control subjects. Furthermore, studies on the pairs of parent-offspring and husband-wife were added in order to evaluate heritability of the countertransport. The Na+-Li+ countertransport of patients with essential hypertension and normotensive subjects with the family history of hypertension was significantly increased in comparison with that of normotensive subjects without the family history. The correlation coefficient of the countertransport in pairs of parent-offspring was significant but not between husband-wife. These results support the concept of a genetic determinant for the countertransport system.

Adult↗