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Biomedical subjects

A Ando

Publications and source records attributed to A Ando.

At least 307 records · Page 17Linked to original sources

Mechanism of tumor and liver concentration of 67Ga: 67Ga binding substances in tumor tissues and liver.

Tumor-bearing animals were administered with 67Ga citrate and tumor homogenates, from which nuclear fraction was removed, and mitochondrial fraction of the host livers were digested with protease (pronase P). After digestion, the supernatants of the reaction mixtures were applied to a Sephadex G-100 column. Resultant eluates were analyzed for radioactivity, protein, uronic acid and sialic acids. Three peaks of radioactivity were obtained by gel filtration. The first peak eluted in the void volume contained a species whose molecular weight exceeded 40,000. The second peak consisted of substances with molecular weights of 9400-40,000. Radioactivity in the third peak was from liberated gallium-67. 67Ga in the second peak was bound to acid mucopolysaccharide and/or the sulfated carbohydrate chain of sulfated glycoprotein. It was thought that 67Ga in the first peak might be bound to some acid mucopolysaccharides. Considering the results of cellulose acetate electrophoresis, 67Ga in the second peak seemed to be bound to acid mucopolysaccharide which contained no uronic acids, and/or to the sulfated carbohydrate chain of sulfated glycoprotein. It was concluded that 67Ga was bound to the acid mucopolysaccharides and/or the sulfated carbohydrate chain of sulfated glycoprotein in tumor tissues and liver lysosomes.

Animals↗

Distribution of RNA coliphages in Senegal, Ghana, and Madagascar.

The distribution patterns of RNA coliphages (phages) in Senegal, Ghana, and Madagascar were investigated by collecting sewage samples from domestic drainage in November, 1980. In Senegal, among 65 sewage samples collected mainly from Dakar and its vicinity, 14 (22%) contained RNA phages (16 strains). By serological analysis, 13 of 16 strains were found to belong to group III. This is consistent with the distribution pattern of RNA coliphages in tropical and subtropical regions of Asia. In Ghana, however, among 106 samples collected from Accra, Suhum, and their vicinities, only seven (7%) contained RNA phages (seven strains) (groups I, II, and III [1:3:3]). In Madagascar, among 124 samples collected from Antananarivo, Moramanga, and their vicinities, seven (6%) contained RNA phages (seven strains) (groups I, II, III, and IV [1:1:1:4]). In spite of the low isolation frequency, it can be said that Madagascar appears to have a unique distribution pattern (abundance of group IV phages) which differs from that of any other countries we have examined. The generality of the distribution pattern of RNA phages in the tropical region (abundance of group III phages) was thus verified at least in Senegal.

Coliphages↗

[In vivo uptake of Ga-67 citrate by an experimental abscess and the mechanism of Ga-67 uptake].

This study was undertaken to investigate the accumulation of 67Ga in an experimental abscess and to elucidate the mechanism of 67Ga uptake in the abscess. Two, three, five, seven and ten days after subcutaneous injection of 0.2 ml turpentine to the rats, 67Ga-citrate was injected to the rats. Twenty-four hours after injection of 67Ga, abscess and organs were excised and uptake rates of 67Ga were assayed. Furthermore, five days after subcutaneous injection of 0.2 ml turpentine to the rats, 67Ga-citrate was injected to the rats, at various time intervals from 10 minutes to 6 days, abscess and organs were excised and uptake rates of 67Ga were assayed. And subcellular distribution of 67Ga in abscess was determined at various time intervals after administration of 67Ga-citrate. On the other hand, to elucidate 67Ga binding substances in abscess, 67Ga-citrate and sodium sulfate-35S were injected to the above rats, respectively. Twenty-four hours after injection, abscess was excised and homogenized. The homogenate was digested with proteinase. After digestion, the reaction mixture was gel-filtered on Sephadex G-100. Eluate samples were assayed for radioactivity, uronic acid and protein. Uptake rates of 67Ga in abscess increased with time after injection of turpentine and reached a plateau 5-7 days later. Ten minutes, 24 hours and 72 hours after injection of 67Ga, uptake rates of 67Ga in abscess were 0.92%/g, 3.3%/g and 5.6%/g, respectively. Uptake rates of 67Ga (24 hours after injection) in abscess was 2.0-3.4 time of tumor uptake rates (previously reported).(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗

Effect of furosemide on mitochondrial electron transport system and oxidative phosphorylation.

The effects of furosemide on the mitochondrial electron transport system and on oxidative phosphorylation were explored. Furosemide above the concentration of 2 X 10(-3) mol/l was found to inhibit state 3 (ADP-dependent) respiration of the rat liver, renal cortex, renal medulla mitochondria. State 4 (resting) respiration was not affected by furosemide. Furosemide above the concentration of 7.5 X 10(-6) mol/l (substrate: glutamate-malate), and above 5 X 10(-6) mol/l (substrate: succinate) inhibited the respiration of rat liver mitochondria released by 3,5-di-tert-butyl-4-hydroxybenzylidenemalononitrile (SF 6847). This fact exactly indicates that furosemide inhibits the electron transport system in mitochondria. Furosemide at the concentration of 4 X 10(-3) mol/l inhibited the activities of NADH cytochrome c reductase and succinate cytochrome c reductase in sonicated mitochondrial subparticles of beef heart by 78.2% and 79.2% of control, respectively.

Animals↗

Influence of chronic renal failure on protein synthesis in rat liver and muscle.

Protein-synthetic activity in the liver and muscle of rats with chronic renal failure (CRF) of 2 weeks' duration was studied by examining RNA/DNA ratios and polysome profiles and in vitro protein synthetic activity of isolated polysomes. CRF was found to cause differential effects on protein synthesis in the liver and muscle. In the liver, CRF caused impairment of protein synthesis only in the fed condition; CRF rats maintained the same "basal" protein synthetic activity as the sham-operated control rats upon 18 hours' starvation. In the muscle, the effect of CRF was manifested only in the starved condition; CRF caused extensive disaggregation of polysomes when animals were starved. It is proposed that the muscle serves as a "reserve" protein when animals sustain a protein-catabolic state such as CRF.

Animals↗

Quantum-chemical and physico-chemical properties of hydrochlorothiazide.

The electronic states of hydrochlorothiazide and its related molecules were obtained by CNDO/2 (CNDO = complete neglect of differential overlap), and van der Waals volume and hydrophobic parameters of the substituent of the 6th position in the benzothiadiazine were estimated. The results were discussed from the viewpoint of the structure-activity relationship analysis. Rather lower LUMO (lowest unoccupied molecular orbital level) of hydrochlorothiazide which had been predicted by the iterated Hückel's Molecular Orbital Method was confirmed by CNDO/2 calculation. The introduction of the sulfamoyl group to the 7th position in the benzothiadiazine ring brought out a negative formal charge for the 7th position. The diuretic effect of the substituent of the 6th position in the benzothiadiazine ring was analysed with respect to its van der Waals volume and its hydrophobic parameter. Van der Waals volume seemed to have a close relationship to diuretic activity. The highest correlated coefficient of the regression equation for the structure-activity relationship was obtained using the formal charge of the 7th position in the benzothiadiazine ring, van der Waals volume and the hydrophobic parameter of the substituent of the 6th position. On the basis of result obtained, the model for the action site of hydrochlorothiazide was proposed, consisting of a rather larger, lipophilic hole and an electrostatic interaction site in the tubular membrane.

Chemical Phenomena↗

Mechanism of tumor and liver concentration of 111In and 169Yb: 111In and 169Yb binding substances in tumor tissues and liver.

Tumor-bearing animals were injected with 111In- and 169Yb-citrate. Tumor homogenates, from which the nuclear fraction was removed, and the mitochondrial fractions of the host livers were digested with pronase P. After digestion, the supernatants of the reaction mixtures were applied to Sephadex G-100 columns. The resultant eluates were analyzed for radioactivity, protein, uronic acid, and sialic acids. Three peaks of radioactivity were obtained by gel filtration. The first peak, eluted in the void volume, contained a species whose molecular weight exceeded 40 000. The second peak consisted of substances with molecular weights of 9400-40 000. Radioactivity in the third peak was liberated 111In and 169Yb. These two nuclides in the second peak were bound to acid mucopolysaccharides and/or the sulfated carbohydrate chain of sulfated glycoprotein. It was thought that the nuclides in the first peak might be bound to some acid mucopolysaccharides. The second peak nuclides seemed to be bound to acid mucopolysaccharide that contained no uronic acids, and/or to the sulfated carbohydrate chain of sulfated glycoprotein. It was concluded that they were bound to the acid mucopolysaccharides and/or the sulfated carbohydrate chain of sulfated glycoprotein in tumor tissues and liver lysosomes.

Animals↗

[Possible role of microthrombus in the pathogenesis of cerebral vasospasm (author's transl)].

Our previous experimental and clinical studies yielded the following results: CSF flow around the subarachnoid vessels is often interrupted by subarachnoid clots; anaerobical incubation of CSF-blood mixture led to a marked fall in the pH value; the vasocontractility of anaerobically incubated CSF-blood mixtures was greater than that of aerobically incubated samples; vasocontraction induced by anaerobically incubated samples was inhibited to a far greater extent the prostaglandin synthesis inhibitor meclofenamic acid than by phenoxybenzamine; cases of asymptomatic marked angiographical vasospasm or of cerebral ischemia with relatively slight angiographical vasospasm were not rarely encountered. Those results lead us to a hypothesis that, in the pathogenesis of cerebral vasospasm, subarachnoid focal acidosis resulting from anaerobical changes of subarachnoid clots may be factor upsetting the balance of the synthesis of TXA2 and PGI2 from PG endoperoxides on the inner surface of cerebral arteries, in favor of TXA2--which plays a role in arterial contraction and in thrombosing with platelet aggregation. On this basis we have been testing the administrations of trapidil, an antagonist and selective synthesis inhibitor of TXA2, in 20 consecutive suitable cases so far, for the prevention of cerebral vasospasm after aneurysmal rupture. Angiographical vasospasm was seen in 9 of the 20 cases, but no signs of cerebral ischemia were detected in 7 of the 9 cases, either clinically or in CT scan. The importance of thrombus formation by platelet aggregation in symptomatic vasospasm are thus suggested.

Adult↗