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Biomedical subjects

N Fukuda

Publications and source records attributed to N Fukuda.

At least 361 records · Page 20Linked to original sources
PubMed1981

Purification and properties of alpha-galactosidase from immature stalks of Saccharum officinarum (sugar cane).

The immature sugar cane stalks studied contained less than 7% sucrose, and showed the activities of enzymes such as invertase, alpha-galactosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, beta-glucosidase, beta-xylosidase, and beta-galactosidase. The alpha-galactosidase was highly purified by ammonium sulfate fractionation, gel filtration on a Sephadex G-100 column, ionexchange chromatography on DEAE-cellulose, and CM-cellulose columns, and heat treatment (60 degrees C, 15 min) in the presence of 0.2 m D-galactose. In polyacrylamide gel electrophoresis, the purified enzyme was homogeneous, having a molecular weight of approximately 46,000. In gelfiltration, it was approximately 47,000. The activity was optimum at pH 4.5 and at 60 degrees C. The purified enzyme hydrolyzed p-nitrophenyl-alpha-D-galactopyranoside (Km, 0.83 mM; Vmax, 25.0 mumol/mg/min), raffinose (Km, 25.9 mM; Vmax, 15.4 mumol/mg/min), and stachyose (Km, 13.0 mM; Vmax 2.7 mumol/mg/min), in addition to melibiose, guar gum, and locust bean gum. The hydrolysis of p-nitrophenyl-alpha-D-galactopyranoside was markedly inhibited by HgCl2, AgNO3, p-chloromercuribenzoate (PCMB), L-ascorbic acid, melibiose, stachyose, and D-galactose. Also the purified enzyme showed a lectin activity with trypsinized erythrocytes.

Chemical Phenomena↗
PubMed1981

Effects of Okinawan sugar cane rind on serum and liver cholesterol and triglyceride levels in the rat.

Okinawan sugar cane rind was fed to Wistar strain rats to examine its effects on the serum and liver cholesterol (Chol) and triglyceride (TG). At the same time, the effects of sugar cane rind on the fecal excretion of neutral sterols of the rats were examined. There were no significant differences found in the food intakes and the liver weight between the rats fed with sugar cane rind and other groups. The addition of 1% Chol to the diet caused a significant increase in body weight gain but the supplementation of sugar cane rind (2%) showed an effect on weight control of rats. The serum Chol and TG levels of the rats given sugar cane rind were lowered significantly. However, the lipid levels in the liver were almost the same when compared with the control groups. The amount of feces excreted by the rats fed with sugar cane rind was about 37% more than that of the control group, and the fecal excretion of neutral sterols was significantly higher.

Animals↗
PubMed1981

[Studies on the genesis of the aortic thudding sound in patients with aortic insufficiency, with special reference to the aortic flow pattern (author's transl)].

To clarify the genesis of the aortic thudding sound (AK), phono-, mechano- and pulsed Doppler echocardiography were performed in 16 patients with pure aortic insufficiency (AI), 3 with AI associated with mild aortic stenosis (AIs) and 5 with AI associated with mitral insufficiency (AI + MI). The results obtained were as follows: 1) AK was composed of two components, that is, one (AK1) occurred in early systole and the other (AK2) near the end point of an ejection systolic murmur. Patients studied were divided into 4 groups following the appearance of AK1 and/or AK2: group with only AK1 (4 cases), group with only AK2 (7 cases), group with both AK1 and AK2 (5 cases) and group without AK (8 cases). 2) AK1 was a low frequency sound and was well recorded from the cardiac base to the right supraclavicular region. AK1 was not observed in cases with mild to moderate AI and with AI associated with mild AS. In atrial fibrillation, when the preceding R-R intervals were long, AK1 was loud and appeared in early systole, and when short, small and in mid-systole. Marked augmentation of AK1 was observed in the first beat after premature ventricular contraction with a compensatory pause. 3) AK2 was also low in frequency and was most intensively recorded near the apex. Although the intensity of AK2 tended to increase in the severe cases of AI, AK2 could be observed in mild to moderate cases. Intensity of AK2 also showed the post-extrasystolic potentiation similar to that of AK1. 4) The carotid pulse showed pulsus bisferiens in all cases with AK2 (group with only AK2 and group with both AK1 and AK2). On the other hand, in cases without AK2 (group without AK and group with only AK1), carotid pulse showed a monophasic systolic wave except 3 cases. These results suggested that there was a close relationship between AK2 and pulsus bisferiens in the carotid pulse. (5) In the apex cardiogram (ACG), systolic notches coincident with AK1 and/or AK2 were observed in 10 of 12 cases with AK2 and in 4 of 9 cases with AK1. In cases without AK, however, no notch was seen in ACG. Therefore, these notches might be resulted from the shock of the anterior chest wall produced simultaneously with the occurrence of AK. 6) Flow patterns at the left ventricular outflow tract (aortic flow patterns) were recorded in 13 cases, including 3 with only AK1, 2 with only AK2, 3 with both AK1 and AK2 and 5 without AK. In 5 of 13 cases the flow patterns were recorded simultaneously with phonocardiograms. Systolic aortic flow showed biphasic patterns in all cases with AK2, and monophasic patterns in cases without AK2. AK1 occurred coincidentally with the first peak of the biphasic flow patterns, and AK2 with the second peak. These results suggested that AK1 might be produced by rapid ejection of massive amount of blood containing a regurgitant flow into the aorta with the ordinarily distensiblwe aortic wall, and AK2 by the clash between the second ejected flow and the reflected flow returning from the peripheral artery against the first ejected flow.

Adult↗
PubMed1980

A dynamic study of rectally absorbed ammonia in liver cirrhosis using [13N]ammonia and a positron camera.

[13N]Ammonia produced by the cyclotron was instilled intrarectally in patients with cirrhosis and other liver diseases to study the turnover of rectally absorbed [13N]ammonia. A positron camera connected to an on-line computer system was used for the measurement of sequential changes of 13N activity in blood and for coincidence positron imaging of the liver and heart. 13N activity over the head was also recorded. Chromatographic analysis of 13N-labeled substances in blood was carried out using a Dowex 50Wx8 column at varying times after the administration. In the control, [13N]ammonia was absorbed quickly and visualized the liver, whereas in patients with cirrhosis, the lungs and heart were first visualized, and 13N activity over the head was also higher. It was suggested that a large proportion of absorbed [13N]ammonia bypassed hepatocytes and reached peripheral tissues in cirrhosis. The heart/liver ratio of 13N and 13N over the head were correlated with various indices of portal hypertension. The relative proportion of nonammonia 13N metabolites in blood was lower at 5 and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia.

Acute Disease↗
PubMed1980

A novel use of chitosan as a hypocholesterolemic agent in rats.

A series of experiments with male rats clearly demonstrated the hypocholesterolemic activity of dietary chitosan. On feeding a high cholesterol diet for 20 days, addition of 2 to 5% chitosan resulted in a significant reduction, by 25 to 30%, of plasma cholesterol without influencing food intake and growth. The concentration of liver cholesterol and triglyceride also decreased significantly. Plasma, but not liver cholesterol-lowering effect, was roughly comparable with that of cholestyramine. Chitosan at the 10% level further reduced plasma cholesterol, but depressed growth. Also, finer chitosan particles tended to restrain growth even at the 2% level. In rats fed a cholesterol-free diet containing 0.5% chitosan for 81 days, the concentration of serum cholesterol was the same with that of the corresponding control, but relatively more cholesterol existed as high-density lipiproteins and less as very low-density lipoproteins. Dietary chitosan increased fecal excretion of cholesterol, both exogenous and endogenous, while that of bile acids remained unchanged. There was no constipation or diarrhea. A proper supplementation of chitosan to the diet seemed to be effective in lowering plasma cholesterol.

Animals↗
PubMed1980

NADH-cytochrome b5 reductase in platelets and leukocytes with special reference to normal levels and to levels in carriers of hereditary methemoglobinemia with or without neurological symptoms.

Normal levels of NADH-cytochrome b5 reductase activity in platelets, lymphocytes and granulocytes were determined. The homogenate of each cell was treated with Triton X-100 after incubation with lipoprotein lipase. The reductase was extracted very well from the cells by this treatment. Moreover, the assay of the reductase activity in the cells became accurate and reproducible by the treatment. The reductase level of each cell was also determined in cases of hereditary methemoglobinemia. It was normal in the case of the disease without mental retardation, and low with mental retardation. This latter case might be due to the deficiency of cytochrome b5 reductase in the whole tissue.

Blood Platelets↗
PubMed1980

[A procedure for recording electroretinogram (ERG) in conscious monkeys, and effects of some drugs (author's transl)].

Stable ERG was successfully recorded using a contact lens-type electrode in conscious cynomolgus monkeys restrained in a monkey-chair with a specially devised head-holder. After adaptation to darkness, single photostimulation evoked ERG consisting of an initial negative wave (a-wave), followed by a positive wave superimposed with oscillatory potentials (b-wave), and a late positive (c-wave). The former two waves were clearly recorded but c-wave was often mixed with artifacts probably due to eye movements. Amplitudes and peak latencies of a- and b-waves increased in progression of dark adaptation and attained to maximum within 20 min. The optimal intensity of photostimulus and time-constant for recording stable a- and b-waves with intermediate amplitudes were found to be 2 joule and 0.1 sec, respectively. The amplitudes and peak latencies (mean +/- s.d.) of a- and b-waves obtained by these conditions were 163.3 +/- 44.9 and 437.0 +/-37.9 microV, and 17.3 +/- 0.5 and 53.5 +/- 3.2 msec, respectively. These waves were reproducible within 25% variations change in a-wave: pentobarbital increased the amplitude of b-wave, whereas ketamine reduced this amplitude. A 3-day treatment with 1,5-di(p-aminophenoxy)pentane (200 mg/kg/day, p.o.), a retinal toxic and behavioral signs of visual dysfunction. Histological abnormality of the retina was also detected. The results indicate that this technique is useful for recording ERG in order to evaluate the effect of chronically treated drugs on visual perception in conscious monkeys.

Adaptation, Ocular↗