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Biomedical subjects

S Sugimoto

Publications and source records attributed to S Sugimoto.

At least 217 records · Page 12Linked to original sources
PubMed1982

Memory for two stimulus-response items in pigeons.

Six pigeons served in a discrete-trial experiment on short-term memory. Combinations of three key positions and two ordinal positions, yielding six possible sequences of stimulus-response pairs, were used as lists of items. A retention interval separated list presentation from the test phase in which two (for Group 1) or three (for Group 2) keys were illuminated with either red or green light. A reinforcer was delivered if a subject pecked the key of the first item on a red trial and the key of the second item on a green trial. When the retention interval was lengthened from one to five or nine seconds, a systematic loss of stimulus control resulted. Lengthening the interval between items from one to eight seconds had a much smaller effect for the birds in Group 1, whereas a systematic loss of stimulus control was found in red trials for the birds in Group 2. The functional relations between choice accuracy and delay provided an empirical basis for analysis of what relations among temporal events can become discriminative stimuli.

Journal Article↗
PubMed1981

Rocket immunoelectrophoresis of C4 and C4d. A simple sensitive method for detecting complement activation in plasma.

Activation of complement component C4 has recently been measured by the quantitation of C4 and C4d (a cleavage fragment of C4) by electroimmunodiffusion in gels containing specific precipitating antibodies for C4 and C4d (Rocket immunoelectrophoresis, RIE). Quantitative measurements of the complement component C4 and its fragment C4d were determined in rocket immunoelectrophoresis (RIE) and compared with measurements of total hemolytic complement activity (CH50) or concentrations of C4 as determined by single radial immunodiffusion (RID). This newly developed RIE assay shows activation of the classical complement pathway and involves electroimmunodiffusion in gels containing specific precipitating antibodies for C4 and its cleavage fragment, C4d. In 37 plasma samples, excellent correlation was demonstrated between the C4 in RIE and CH50 (r = .70) and C4 by RID (r = .87). In vivo activation of C4 was determined by measuring the ratio of C4d to C4; 21 of the plasma samples assayed had ratios greater than 1.1 indicating activation of C4. In 13 of the plasma samples there were correspondingly low CH50 values, whereas 8 had normal CH50 levels. Therefore, activation can be detected in those instances when other measurements (CH50 and C4 quantitation) are normal. Thus the RIE assay for plasma C4 activation appears to be the most sensitive method available for assessing in vivo activation of the classical pathway of complement.

Animals↗
PubMed1981

[Clinical application of cefsulodin to Pseudomonas aeruginosa infections in the surgical field (author's transl)].

Cefsulodin (CFS), a new antipseudomonas cephalosporin, was clinically evaluated for treatment of the Pseudomonas aeruginosa infections in the surgical field to obtain the following results. 1. CFS was administered to total 11 cases of the surgical infections caused by P. aeruginosa, comprising of 5 cases with wound infections, 3 cases with infected burn and 1 case each with muscular abscess, decubitus and postoperative pneumonia in 0.5 approximately 1 g twice a day by intravenous bolus or drip infusion. Good clinical responses were obtained in 9 out of 11 cases (81.8%). 2. Bacteriological responses were observed in all cases. P. aeruginosa was eradicated in 9 cases and suppressed in 2 cases by CFS treatment. However, replacement of pathogens with the other organisms was observed in 6 out of 8 cases caused by P. aeruginosa only. 3. Neither objective and subjective side effects nor abnormalities of laboratory tests associated with CFS treatment were observed. 4. It can be, therefore, concluded that CFS is one of the useful drugs for treatment of the surgical infections caused by P. aeruginosa.

Adult↗
PubMed1980

Computerized tomography findings in dural arteriovenous malformations. Report of three cases.

Changes in the brain parenchyma and cerebrospinal fluid spaces were demonstrated in three cases of dural arteriovenous malformations by computerized tomography (CT). In various combinations, there were 1) vermiform or patchy enhancement after intravenous contrast infusion, 2) abnormal decreased density mainly in the white matter, 3) local mass effect, 4) hydrocephalus, 5) dilatation of the major venous sinus system, and 6) prominent vascular grooving of the skull inner table. Most of these changes were secondary to raised sinus pressure caused by arteriovenous shunt. It was also demonstrated by serial CT that some elements improved after artificial embolization or surgical excision of the malformations.

Aged↗
PubMed1980

Purification and properties of dissociable chorismate mutase from Brevibacterium flavum.

Component B of chorismate mutase of Brevibacterium flavum, the first enzyme specific for phenylalanine and tyrosine biosynthesis, was purified to near homogeneity. The molecular weights of component B and its subunit were estimated to be 25,000 and 13,500, respectively. Component A (previously purified) or B alone did not show any chorismate mutase activity but together they showed activity. The enzyme activity was not proportional to the amount of the enzyme. The optimum pH of the reaction was 8.0. Double-reciprocal plots of the reaction rate against chorismate concentration curved upwards. S0.5 and Hill coefficient values were estimated to be 5.5 mM and 3.1, respectively. The chorismate mutase component A and 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetase activities of component A were labile and were stabilized by tryptophan, dithiothreitol or cobalt ions. Phenylalanine and tyrosine inhibited the enzyme activity partially and competitively. The simultaneous presence of phenylalanine and tyrosine caused cumulative inhibition at saturated concentrations. The concentrations of phenylalanine, tyrosine, and phenylalanine plus tyrosine (each) giving 50% inhibition under the standard conditions were 0.0041, 0.095, and 0.0023 mM, respectively. Tryptophan activated the enzyme about 6-fold. The concentration giving the half-maximum activation was 0.0023 mM. Furthermore, tryptophan overcame the inhibition caused by phenylalanine and tyrosine. The tryptophan activation affected only S0.5, not the maximum velocity or the Hill coefficient. beta-2-Thienylalanine, m-fluorophenylalanine, alpha-methylphenylalanine, and phenylalanine hydroxamate inhibted the enzyme in the same way as phenylalaine, while tyrosine hydroxamate and alpha-methyltyrosine inhibited it in the same way as tyrosine. 4-Methyltryptophan, 5-fluorotryptophan, 6-fluorotryptophan, tryptophan hydroxamate, and alpha-methyltryptophan activated the enzyme in the same way as tryptophan.

Amino Acids↗
PubMed1979

[Behaviors of nitrato complexes of nitrosylruthenium in aqueous solutions (author's transl)].

Nitrato nitrosylruthenium complexes [RuNO(NO3)x(H2O)5-x] (3-x)+ readily dissociate in aqueous solutions with decrease in pH and increase in electrical conductivity of the solutions. This study aimed to elucidate the behaviours of dissociation of the complexes with time. The change in the amount of undissociated complexes was determined with time. The results indicated that the dissociation was a multi-order reaction involving both protolysis and hydrolysis. The protolysis completed in relatively short period within(several tens of minutes), but it depended on the concentration of the complexes in the solution. The completion of the protolysis and the formation of the resulting dissociation products were observed by absorption spectrometry. The dissociation products, which were assumed as aquohydroxy complexes, underwent the successive step-wise dissociation for a prolonged period as revealed by pH measurements. The rate constants involved in the step-wise dissociation, process were obtained. The degree of dissociation and dissociation constant of the complexes were measured by conductometry.

Chemical Phenomena↗
PubMed1979

[Study on decontamination of radioactive ruthenium by steel wool in waste solution (author's transl)].

Tracer experiments were done in order to establish a decontamination process of 106Ru in radioactive waste solution by column method paying special attention on the solution of nitratonitrosyl complex of Ru which is often encountered as a low level radioactive waste solution. It turned out that metallic iron was the most effective decontaminating agent among the several tens of materials tested. The decontamination factor (DF) of 106Ru increased in proportion to the total surface area of iron and it sensitively depended on the oxidation state of the surface as revealed by the batchwise and columnwise tests. Iron samples with high corrosiveness gave a much larger DF than those with low corrosiveness. The decontamination process proceeded as iron was being oxidized via Fe(metal)leads toFe(II)leads toFe(III). As the results, the DF initially increased after initiating the passage of water through the column but it then decreased as the oxidation process became inactive. An excellent durability up to 10000 bed volumes was demonstrated by the column method at a high average DF of 150.

Alloys↗
PubMed1979

[Behaviours of trinitratonitrosyl complexes of ruthenium in dilute nitric acid solutions (author's transl)].

This study aimed to elucidate the protolysis and condensation processes of the Ru complexes in relation to the concentration of nitric acid. The compositions of the dissociated and undissociated complexes were determined by the extraction with tributyl phosphate (TBP) and absorption spectroscopy in order to follow the rather rapid protolysis reaction of the complexes. The test solutions were prepared by dissolving the freshly obtained complexes into 0.50-0.001 M nitric acid solutions. The amounts of the undissociated complexes were determined at different elapses of time in the test solutions. The protolysis became significant when the concentration was below 0.15 M, and the dissociation rate suddenly increased at this concentration. At the concentrations above 0.2 M, the absorption peak of the complexes at 480 nm survived even after 144 hours. But below 0.15 M, the formation of dissociation products by protolysis was observed after the disappearance of the absorption peak. The amount of dissociation products rapidly increased after the preparation of the test solution as the concentration decreased below 0.15 M.

Chemical Phenomena↗