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Biomedical subjects

S Eguchi

Publications and source records attributed to S Eguchi.

At least 361 records · Page 20Linked to original sources
PubMed1983

Taurocyamine-utilizing mutants from a wild-type strain of Pseudomonas.

Pseudomonas sp. ATCC 14676 produces glycocyaminase (EC 3.5.3.2) and guanidinobutyrase (EC 3.5.3.7). Taurocyamine (2-guanidinoethane sulfonate) is a gratuitous inducer of both of these amidinohydrolases. Mutants of this organism capable of utilizing taurocyamine as a nitrogen source were isolated directly from the wild-type cells after uv irradiation or treatment with N-methyl-N'-nitro-N-nitrosoguanidine; frequencies of mutations observed under appropriate conditions were above 10(-7). Strain U2-3-3, which was selected from the 11 isolated taurocyamine-utilizing strains, was proved to be derived from the wild-type strain. Both taurocyamine and 4-guanidinobutyrate were able to induce an enzyme of strain U2-3-3 that liberated urea from taurocyamine, whereas glycocyamine failed to induce the system. The activity of the enzyme toward taurocyamine was found to be about one-third of that toward guanidinobutyrate when both taurocyamine and guanidinobutyrate were used as inducer. These observations suggest that the enzyme of the mutant capable of hydrolyzing taurocyamine has emerged from guanidinobutyrase of the wild-type strain which hydrolyzes taurocyamine at a very low rate, probably as a result of a point mutation in the structural gene.

Culture Media↗
PubMed1983

[Left ventricular regional wall motion after correction of tetralogy of Fallot].

Cardiac function and left ventricular regional wall motion were examined using two-dimensional echocardiography in 40 post-operative patients of tetralogy of Fallot (TOF) of an average of 13 years after the correction. From the data of treadmill exercise test and cardiac catheterization, patients were classified into two groups; cases with complete ability for treadmill test (Group A, n = 22), and disabled for the test and the right ventricular systolic pressure above 50 mmHg (Group B, n = 18). Compared with the control group (n = 10), the patient groups had greater cardiothoracic ratios (CTR) and right/left ventricular dimensions (RVd/LVd) (p less than 0.001), and Group B had a greater CTR and RVd/LVd than Group A (respectively p less than 0.001). Compared with the control group, the patient groups had no significant differences in corrected ejection time, fractional shortening and mean velocity of circumferential fiber shortening, and no difference was noted between Group A and Group B. Left ventricular regional wall was divided into 12 segments around the left ventricular circumference on the two-dimensional short-axis view and the regional wall motion was evaluated on the basis of [(diastolic-systolic)/diastolic left hemiaxial length X 100%] values. In Group B, akinetic or dyskinetic wall motion was visualized at the interventricular septum and left ventricular posterior wall, but there was no abnormal motion in the control group and Group A. We concluded that even in postoperative patients with preserved cardiac function at rest, some of them had abnormal left ventricular regional wall motion due to the persistent right ventricular overload or corrective patch, resulting in low exercise capacity.

Adolescent↗
PubMed1982

Mechanism of inducing autologous antibody formation in nephrotoxic serum nephritis.

The role of the heterologous antibody fixed in the kidney was evaluated by means of transplantation of a nephritic kidney to a normal recipient in the rat. An intravenous injection of 0.5 ml of nephrotoxic serum could not induce distinct changes in the heterologous phase, but it could cause mild or moderate changes in the autologous phase. Titration of rat antibody to rabbit IgG according to passive hemagglutination test showed that rabbit IgG fixed in the transplant could induce autologous antibody formation with a similar intensity to nephrotoxic serum given intravenously, indicating that fixed antigen played the most important role in autologous antibody formation and other factors, such as the kidney-fixing rabbit IgG remained in circulation or fixed in other tissues and the gamma-globulin other than anti-kidney antibody, might be less important. It was unclear which antibody, fixed or dissociated from the transplant, played the more important role in stimulating antibody formation.

Animals↗
PubMed1982

Comparative study of effects of adrenaline, dobutamine and dopamine on systemic hemodynamics and renal blood flow in patients following open heart surgery.

In 10 patients following open heart surgery, adrenaline, dobutamine and dopamine were administered, and the changes in hemodynamic parameters and renal blood flow (RBF) were examined. RBF was determined by the local thermodilution method. Prior to the application of this method in clinical measurement, reliability of the method was checked using a model circuit. The correlation between the actual flow and flow obtained with this method was high (r = 0.999, p less than 0.005, n = 8). Reproducibility in repeated measurements was excellent, r = 0.997 (p less than 0.005, n = 8) in the model circuit and r = 0.985 (p less than 0.005, n = 89) in the clinical measurement. Adrenaline at rates of 0.02--0.08 microgram/kg/min showed a marked inotropic action without any significant change in RBF. With 0.04 microgram/kg/min of adrenaline, the RBF/CO (cardiac output) ratio declined significantly. We conclude that adrenaline is often effective in patients following open heart surgery, but renal vasoconstriction is the major disadvantage. After a 10-min administration of 2, 4 and 8 micrograms/kg/min of dobutamine, cardiac index (CI) and stroke volume index (SVI) showed a stepwise increase in accordance with an increase of dosage, and RBF also increased with CO. Consequently, no significant change in RBF/CO was found. Mean left atrial pressure (LAP) or mean pulmonary arterial wedge pressure (PAWP) decreased in 4 of 7 patients with 8.0 micrograms/kg/min of dobutamine. Thus, dobutamine is an excellent beta 1-adrenergic agonist with a weak alpha-action on both peripheral and renal vessels. With 2.0--2.5 micrograms/kg/min of dopamine, RBF increased by 15.5% (p less than 0.05). while no significant increase appeared in CI. With 4.0 micrograms/kg/min or more of dopamine, CI and SVI increased. With 16--20 micrograms/kg/min of dopamine, RBF increased by up to 44.8%. Significant increase of mean LAP or mean PAWP was observed with 8.0--10.0 micrograms/kg/min or more of dopamine. These findings indicate that the potential increase o LVEDP (left ventricular end-diastolic pressure) with 8--10 micrograms/kg/min or more of dopamine exerts a disadvantageous effect in patients following open heart surgery. However, the effect on the renal hemodynamics, especially with small doses of dopamine, is unique and not observed with adrenaline or dobutamine.

Adolescent↗
PubMed1982

Surgical experience with anatomically corrected malposition of the great arteries without subpulmonary conus.

A three-year-old boy was operated on with the diagnosis of anatomically corrected malposition of the great arteries (S,D,L), ventricular septal defect, and mitral regurgitation. During the operation, it was found that the subpulmonary conus was absent. Ventricular septal defect was patch-closed, and the mitral valve was repaired. The patient was well after the surgery. This is the first case report to our knowledge of the successful surgical repair in anatomically corrected malposition of the great arteries without subpulmonary conus. Anatomically corrected malposition of the great arteries does not always have bilateral conus as once proposed, and the importance of the differentiation from the corrected transposition of the great arteries is emphasized.

Child, Preschool↗
PubMed1981

Easy method for measurement of opening angle of Björk-Shiley valve with two computers. Proof of floating phenomenon of Björk-Shiley valve.

A new method for measuring the opening angle of Björk-Shiley valve (B-S valve) was reported in 1977. However, this method is complicated enough to permit quick calculation of the opening angle in multiple frames of one cinefilm. We devised a new method with using two computers (NAC Cardias GP 2000, TEXAS TI-59) for calculating the opening angle of the B-S valve. We measured the opening angle of 7 cases (they were all implanted B-S valves, 5 were mitral and 2 were aortic). Results are the following: (1) The maximum opening angle ranged from 54 degrees to 65 degrees and the mean value was 58.1 degrees. (2) We showed the floating phenomenon of B-S valve with our method. (3) We showed the accuracy of our method by measuring 10 times the same photograph of B-S valve. (4) We showed that our method is very accurate by comparing the values calculated by our method with those calculated directly from the valve which was removed from a patient. (5) It takes less than 30 minutes to calculate the opening angle of 60 frames (we took 60 frames of cine-film per minutes.

Aortic Valve↗