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Biomedical subjects

T Tsuchiya

Publications and source records attributed to T Tsuchiya.

At least 829 records · Page 46Linked to original sources

A synthesis of dihydrostreptomycin.

A key protected streptidine derivative (3) useful for the synthesis of antibiotics of streptomycin series was prepared by hydrolysis of an acylated dihydrostreptomycin (DHSM) derivative (2), and it was condensed with a protected dihydrostreptobiosaminyl chloride (5) to give two condensation products (6 and 7). By deblocking, 6 was led to DHSM and 7 to a biologically inactive isomer (8) of DHSM. From the PMR spectrum of 4-O-mesyl derivative (4) of 3, the benzyloxycarbonyl and acetyl groups were concluded to be attached to the end nitrogens of the guanidine groups.

Chemical Phenomena↗

Synthesis of 5''-amino-3,5''-dideoxybutirosin A.

The titled compound was prepared by condensation of 3'-deoxyparomamine derivative (5) with 2,3-O-bis(p-nitrobenzoyl)-5-O-tosyl-D-xylofuranosyl bromide followed by 1-N-acylation with the active ester of (S)-4-benzyloxycarbonylamino-2-hydroxybutyric acid. The compound was slightly more active than 3'-deoxybutirosin A against Pseudomonas.

Anti-Bacterial Agents↗

1- and 3-deamidino derivatives of dihydrostreptomycin and some 1-N-acyl derivatives.

1-Deamidino-, 3-deamidino- and 1,3-di(deamidino)dihydrostreptomycin (1, 2, 3) were prepared by treatment of dihydrostreptomycin (DHSM) with ammonia at 100 degrees C. The 3-guanidino group of DHSM is suggested to be more important than the 1-guanidino group for the antibacterial activity of DHSM. 1-N-[(S)-4-Amino-2-hydroxybutyryl) and 1-N-[(S)-4-guanidino-2-hydroxybutyryl] derivatives (4, 6) of 1-deamidinodihydrostreptomycin were futher prepared.

Acylation↗

Flow control in prolonged ventricular bypass and clinical application in 15 patients.

Long-term experiments employing left ventricular or biventricular bypass with local heparinization and blood filtration for up to 48 days was conducted in 51 calves at different flow rates. The principle of flow control obtained was applied to 15 patients in critical cardiac states. An avcothanized extracorporeal circuit consisted of heparin and protamine microperfusion lines, Pall filter, and nonpulsatile pump. Bypass with flow rates at 30--40% of cardiac output was conducted between 3 and 48 days. Survival was obtained in 34 of 36 calves. Bypass with flow rates at 60--80% of cardiac output was associated with 6 deaths in the 10 calves who underwent the procedure. Bypass with flow rates over 90% of cardiac output was often technically difficult and only 2 of 5 calves survived. Hemodynamic changes correlated well with the above results. In clinical cases flow rate was adjusted up to a maximum of 100% of left ventricular blood flow initially and thereafter to 30--40% of cardiac output for chronic support. A total of 15 patients with myocardial infarction, myocarditis and failing cardiac condition post-surgically were supported for 9--172 hrs. Six of the 15 survived. Adequate flow control in ventricular bypass support is important and the regimen developed in experimental studies proved effective clinically.

Adolescent↗

Aortic cannulation for cardiopulmonary bypass.

The surgical technique and complications of aortic cannulation for arterial return in total body perfusion utilizing oxygenator were presented based on our experience of 400 patients. Major complications encountered were laceration and bleeding (1 case), hematoma formation and bleeding (2 cases), and malpositioning of the catheter resulting in mild brain damage (1 case). All underwent re-operation with 4 survivals. Aortic cannulation is simple to perform, easy to maintian stability in cardiopulmonary bypass and with much less risk of retrograde dissection in all ages.

Aorta↗