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Biomedical subjects

H Okuda

Publications and source records attributed to H Okuda.

At least 469 records · Page 26Linked to original sources
PubMed1978

Microvascular anastomosis and its application on the replantation of amputated digits and hands.

Successful microvascular anastomosis depends upon the applications of magnifications, special instruments and fine suture materials, and the surgeon's skill in the technique. The key points of one millimeter vessel anastomosis are the wall-to-wall coaptation of the vessel ends, the fewer number of interrupted stitches with relatively loose knot. To gain good coaptation, an oblique insertion of a needle through the vessel wall must be used. In a thin-walled vein repair, the lumen should always be kept open with frequent irrigations. Between July 1965 and December 1976, 150 digits out of 168 in 111 cases and 11 hands in 11 patients were successfully replanted. All tissues must be repaired primarily. The repair of artery is performed first, recirculation is allowed with systemic heparinization, followed by vein anastomosis. The rehabilitation is commenced from the first day. To gain good function, several reconstructive surgeries may be necessary on the replanted digit or hand.

Adolescent↗
PubMed1977

Traumatic amputation of digits: the fate of remaining blood. An experimental and clinical study.

Experimental studies on rabbit ears amputated by either a clean sharp division or severed by a crushing blow showed that twice as much blood remained in the crush group. Microthrombi and tissue thrombi were seen in this group only. A review of 142 digital replantations performed over a 10 year period showed 126 survivals. Ninety-three were complete amputations and 80 of these survived; 49 were incomplete amputations and 46 survived after revascularization attemps. Of 74 clear amputations, 68 survived; of 68 crush-type amputations, 58 survived. Circulatory disturbances occurred in 36 replanted digits; 16 could not be salvaged. The primary cause of complications was venous obstruction. In 80 digital replantations done from January, 1974, to December, 1975, success was obtained in 75 (93.75 percent). Irrigation of vessels of the severed part is done only in cases of double level amputation, severely crushed or those due to avulsion. Heparin, low molecular weight dextran, urokinase, and antibiotics are given for several days after operation.

Amputation, Traumatic↗
PubMed1977

Studies on adrenaline-induced lipolysis in artificial lipid micelles.

Lipid micelles were prepared by incubating a mixture of glycerides (triolein, diolein, and monoolein), and lecithin in Krebs-Ringer phosphate buffer at 37 degrees C for 30 min. It was found that adrenaline stimulated the release of free fatty acids in a lipolytic system consisting of the lipid micelles and adipose tissue lipase. Adrenaline did not increase the cyclic AMP content of the reaction mixture. Dibutyryl cyclic AMP, theophylline, and phospholipase C increased the rate of lipolysis in the system but cyclic AMP and phospholipase D did not.

Bucladesine↗
PubMed1977

Identification of acylcholine acyl-hydrolase with carboxylic ester-hydrolase in human serum.

The relationship between pseudocholine esterase [acylcholine acyl-hydrolase, EC 3.1.1.8] and non-specific esterase [carboxylic ester-hydrolase, EC 3.1.1.1] in human serum was investigated. The purified preparation (purified 500-fold) which had both pseudocholine esterase and non-specific esterase activities, was found to give a single band with faint tailing on polyacrylamide gel electrophoresis. The ratio of the specific activity of pseudocholine esterase to that of non-specific esterase remained essentially the same during the purification procedures. Furthermore, the pseudocholine esterase was demonstrated to be identical with the non-specific esterase by immunochemical studies. All these results suggest that activities of pseudocholine esterase and non-specific esterase in human serum derive from the same enzyme molecule. Observation of Yoshida-cho in Ehime after the application of organophosphorus insecticide supported our results: the activity of pseudocholine esterase was found to be reduced with a concomitant decrease in the activity of non-specific esterase. Based on these results, the physiological significance of the esterase is discussed.

Butyrylcholinesterase↗
PubMed1977

Effects of free fatty acids on fibrinolytic activity.

A novel method for the estimation of fibrinolytic activity is proposed. In this method, a fibrin clot suspension is used as a substrate (fibrin is known to be a physiological substrate of plasmin). The fibrin clot suspension was prepared by homogenization of human fibrin clots. With this method, we found that free fatty acids inhibited the plasmin activity, and long-chain, unsaturated free fatty acids had a particularly strong inhibitory action on plasmin. As regards the mechanism of the inhibitory action, free fatty acids may not inhibit complex formation between plasmin and fibirin, but may make it impossible for plasmin to act on fibrin due to deformation of the surface of the fibrin clot.

Fatty Acids, Nonesterified↗
PubMed1977

Comparative studies on the metabolism of 2-(tetrahydrofuryl)-5-fluorouracil and 5-fluorouracil.

5=Fluorouracil inhibited DNA synthesis markedly using various DNA precursors such as deoxyuridine, orotic acid, uracil, and uridine except for thymidine. 2-(Tetrahydrofury)-5-fluorouracil (FT-207) did not inhibit DNA synthesis with any of the precursors tested. The metabolisms of 5-fluorouracil and FT-207 in mice and rats were studied. When administered intravenously 5-fluorouracil was rapidly degraded to fluoro-beta-alanine in both mice and rats, while at most 70% of FT-207 was slowly degraded after a prolonged period. The metabolites of FT-207 were found to be 5-fluorouracil and fluoro-beta-alanine in both species of animals. In vitro degradation of FT-207 into 5-fluorouracil was observed mainly in the microsomal fraction in the presence of NADPH. This result suggested that microsomal electron-transport system was concerned with the degradation of FT-207.

Alanine↗
PubMed1976

Further studies on the mechanism of adrenaline-induced lipolysis in lipid micelles.

Lipase [EC 3.1.1.3] depleted lipid micelles, in which lipolysis was not elicited by adrenaline, were prepared from lipid micelles. When these lipase-depleted lipid micelles incubated with adipose tissue extract containing lipase activity, adrenaline-induced lipolysis was restored to almost the same level as that of native lipid micelles. Adrenaline-induced lipolysis was not restored when the lipase-depleted lipid micelles were homogenized or sonicated. Various tissue extracts from kidney, lung, liver, and pancreas, and post-heparin plasma, which contained lipase activity, restored adrenaline-induced lipolysis in lipase-depleted lipid micelles.

Adipose Tissue↗
PubMed1975

Intracellular distribution of various enzymes concerned with DNA synthesis from normal and regenerating rat liver, and Yoshida sarcoma.

During the fractionation of various enzymes concerned with DNA synthesis from the postmicrosomal supernatant fraction of various tissues, DNA polymerace [EC 2.7.7.7], thymidine kinase [EC 2.7.1.75], dTMP kinase [EC 2.7.4.9], deoxycytidine kinase [EC 2.7.1.74], and deoxycytidine monophosphokinase (dCMP kinase) [EC 2.7.4.14] were found in the pellet fraction of postmicrosomal supernatant. Further, the uridine kinase [EC 2.7.1.48] and aspartate transcarbamylase [EC 2.1.3.2] activities of postmicrosomal supernatant from various tissues were also present in this pellet fraction. The activities of DNA polymerase, thymidine kinase, uridine kinase, and aspartate transcarbamylase from normal and regenerating rat liver, and Yoshida sarcoma were higher in the pellet fraction than in the supernatant. On the other hand, the activities of dTMP kinase, dCMP kinase, and orotidine-5'-phosphate decarboxylase [EC 4.1.1.23] were lower in the pellet fraction than in the supernatant. The pellet fractions of regenerating rat liver and Yoshida sarcoma showed a remarkable incorporation of various precursors (thymidine, dTMP, deoxycytidine, and dCMP) into DNA in the presence of a suitable DNA template, ATP and all four deoxynucleoside 5'-triphosphates for DNA synthesis. Normal adult rat liver catalyzed a much smaller incorporation of all these precursors, except for dCMP.

Animals↗
PubMed1975

Studies of the clinical application of serum leucine aminopeptidase (LAP) activity determined with leucinamide as substrate.

A new method was presented for the determination of leucine aminopeptidase (LAP). The principle of the method consisted in the measurement of ammonia liberated by the action of LAP with direct colorimetry. Leucine naphthylamide has been widely used as substrate for the determination of LAP (Nap-method), but leucineamide was used (NH3-method) in this study, and the enzyme activities determined by the both methods were compared in various diseases. Serum LAP activity in acute hepatitis was much higher in NH3-method than in Nap-method, but the activity in obstructive jaundice was much higher in the latter than in the former. It was demonstrated that the serum of normal rats and CCl4 treated rats contained isozymes (LAP-I and II) which showed the different substrate specificities toward leucinamide and leucine naphthylamide. LAP-I activity was much higher, but LAP-II activity was much lower in the NH3-method than in the Nap-method. LAP-I activity was remarkably elevated by the NH3-method, but not by the Nap-method in the serum of CCl4 treated rats. The results suggested that leucinamide was preferable substrate for the measurements of activities of serum LAP in the clinical examinations.

Ammonia↗