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Biomedical subjects

T Oku

Publications and source records attributed to T Oku.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Sequential internal mammary-coronary artery bypass].

A total of ten patients have undergone sequential bypass grafting of the internal mammary artery (IMA) to the coronary arteries at Osaka Medical College. Operative procedures included left IMA bypass to the left anterior descending (LAD) artery and its major diagonal branch in six patients; to the obtuse marginal branch and diagonal branch in three patients; and to the first and the second diagonal branches in one patient. The right internal mammary artery was concomitantly utilized in 4 patients and saphenous vein graft was also utilized in 6 patients. Postoperative angiographic studies were performed in nine patients within 6 months after operation and in all 18 sites of IMA anastomoses, the IMA sequential grafts were patent. Since sequential IMA-coronary bypass technique means the increase of arterial graft, we believe that this technique should be used for multivessel coronary revascularization especially in younger patients.

Adult↗
PubMed1989

[Poststernotomy mediastinitis treated by early surgical intervention].

Poststernotomy mediastinitis in 67-year-old female was successfully treated by early operation after coronary artery revascularization using bilateral internal mammary arteries and gastroepiploic artery. Wider debridement including sternum, ribs, mediastinal fat and connective tissues, and transfer of rt-pectoralis major muscle flap into the mediastinum to obliterate the dead space was performed. The sternal wound was primarily closed without postoperative irrigation. The sternum was stayed open without using any artificial substitute. In conclusion, the early diagnosis and operation is the key for successful treatment of poststernotomy mediastinitis. Wider debridement including sternum and ribs with perioperative lavage by diluted povidone-iodine solution and antibiotic solution should be done aggressively, and the transfer of the major pectoral muscle flap and skin closure without postoperative irrigation is an effective method of choice. Additional reconstruction of anterior chest wall should be considered if necessary, when the inflammatory process is subsided.

Aged↗
PubMed1989

[A clinical study of diltiazem administration using cold glucose-insulin-potassium cardioplegic solution--comparison between diltiazem cardioplegia and diltiazem pretreatment].

A recent idea of myocardial injury during open heart surgery is thought to be caused by the intracellular calcium overload. So, one possibility for improving myocardial protection is expected on the blocking agents of transmembrane calcium movements. This study was designed to clarify the effect of Diltiazem, a kind of calcium blocking agents, on myocardial protection in terms of hemodynamics and plasma Diltiazem concentration. 38 patients who underwent coronary artery bypass grafting using glucose-insulin-potassium cardioplegic solution (GIK) were divided into three groups Control (CO) group: no Diltiazem administration. Diltiazem cardioplegia (DC) group: GIK containing 7.5 mg/l Diltiazem was used. Diltiazem pretreatment (DP) group: Diltiazem was administered intravenously 1.5 micrograms/kg/min before operation to after operation continuously. Plasma Diltiazem concentration was constantly kept at about 150 ng/ml during 24 hours after surgery in DP. On the contrary, in DC, the level was very high (10,000 ng/ml) during aortic cross clamp but decreased about 50 ng/ml at 3 hours after surgery, and Diltiazem was not detected in CO. DC included many cases of bradycardia required pacing, however, it diminished as plasma concentration decreased. Aid of catecholamin administration was reasonable in three groups. DP and DC included many cases of commendable cardiac function in terms of cardiac index, systemic vascular resistance and left ventricular work during acute stage of surgery, and there were no coronary spasm and perioperative infarction. It is concluded that Diltiazem is effective to keep good cardiac function after reperfusion, and combined (Diltiazem pretreatment--1.5 micrograms/kg/min drip infusion-and Diltiazem cardioplegia-total dose 150-300 micrograms/kg) administration should be advisable.

Calcium Channel Blockers↗
PubMed1989

[Multiple cerebral infarction following coronary artery bypass grafting for the patient with calcified aorta--a case report].

The cardiac surgeon occasionally may encounter a diseased or rigidly calcified aorta in the patient requiring myocardial revascularization. In this paper, a 72-year-old woman who suffered from neurological injury following coronary artery bypass grafting due to embolization of atheromatous debris from the calcified ascending aorta was described. A review of the literature was also performed to emphasize the importance of the recognition, and management of the calcified and diseased ascending aorta.

Aged↗
PubMed1988

Antitumor activity and hematotoxicity of a new, substituted dihydrobenzoxazine, FK973, in mice.

FK973, a new, substituted dihydrobenzoxazine (11-acetyl-8-carbamoyloxymethyl-4-formyl-14-oxa-1,11- diazatetracyclo[7.4.1.0.0]tetra-deca-2,4,6-trien-6,9-diyl diacetate), was obtained by chemical modification of a novel antibiotic which was isolated from the fermentation products of Streptomyces sandaensis No. 6897. FK973 had cytotoxic effects against in vitro cultured human and murine tumor cells. FK973 in doses of 0.032-5.6 mg/kg (i.p.) had stronger antitumor activities and higher chemotherapeutic ratio than mitomycin C against such murine ascitic tumors as P388 and L1210 leukemia, B16 melanoma, M5076 reticulum cell sarcoma of ovarian origin, Colon 26 carcinoma, Ehrlich carcinoma, and MH134 hepatoma. In tests against murine and human solid tumors implanted s.c. in normal mice and nude mice, respectively, FK973 (i.v.) inhibited growth of murine tumors (M5076 sarcoma, Colon 38 carcinoma, B16 melanoma, and Lewis lung carcinoma) by 66-100% and human tumors (LX-1 lung, MX-1 mammary, and SC-6 stomach carcinoma) by 84-99%. In studies with drug-resistant P388 leukemia, FK973 was also effective against vincristine-resistant P388, moderately effective against mitomycin C (MMC)- and adriamycin-resistant P388, and partially effective against cyclophosphamide-resistant P388 cells in mice. Leukopenic effects of FK973 and MMC in mice were comparable at doses which gave antitumor activity almost equally. FK973 had no effect on the numbers of platelets and red blood cells, whereas MMC markedly decreased both. FK973 decreased the numbers of colony forming units in spleen and in culture and the effect was less than that of MMC. Therefore, FK973 may give weaker myelosuppression than MMC. The results suggest that FK973 will be a beneficial drug for the treatment of cancer.

Animals↗
PubMed1988

Augmented antitumor effect of recombinant human interleukin-1 alpha by indomethacin.

In murine syngeneic tumor models, the antitumor effect of recombinant human interleukin-1 alpha (rHu IL-1 alpha) was significantly augmented by oral coadministration of indomethacin (IND). The augmentation was more or less observed by various routes of rHu IL-1 alpha (i.m., i.v., and intratumoral routes), against various tumors (Meth A sarcoma, colon 26 adenocarcinoma, B16 melanoma, and Lewis lung carcinoma) and irrespective of administration timings (in early and late stages of tumor growth). This results suggests that prostaglandin E2 produced by host cells in response to rHu IL-1 alpha and/or by tumor mass might interfere with the antitumor activity of rHu IL-1 alpha and also that cyclooxygenase inhibitors such as IND might counteract such interference. In the combination of rHu IL-1 alpha with IND, its efficacious doses (5-50 micrograms/kg) against murine tumors were at least 300-3000 times lower than its median lethal dose (more than 15 mg/kg). In addition, IND partially prevented the loss of body weight attributed to rHu IL-1 alpha injections at relatively high doses. Combined use of rHu IL-1 alpha with IND seems to be desirable from both therapeutic and toxicological viewpoints.

Adenocarcinoma↗
PubMed1988

Titanium-nickel intravascular endoprosthesis: a 2-year study in dogs.

Twelve 5-mm-internal-diameter intravascular endoprostheses of noncorrosive, shape-memory titanium-nickel (TiNi) alloy were delivered transluminally by catheter and implanted in the iliac (n = 10) and femoral (n = 2) arteries of six normal dogs for either 1 or 2 years in order to evaluate the implantation technique and long-term effects. The patency rates were as follows: at 1 month, 92% (11/12); at 1 year, 100% 11/12 widely patent; 1/12 recanalized); and at 2 years, 100% (3/4 without stenosis; 1/4 with 20% stenosis). No migration, erosion, inflammation, surface thrombus, or stenosis of the side branches was seen; an absence of untoward angiographic and histopathologic effects was detected at 1 and 2 years. The neointima was completely endothelialized, without changes in thickness over time, 229.3 +/- 127.6 microns after 1 year and 223.3 +/- 216.7 microns after 2 years (p = not significant). The neointimal layer became thicker toward its distal aspect (p less than or equal to .05). Satisfactory delivery, long-term patency, and biocompatibility (manifested as a thin, stable neointima) were observed for the TiNi intravascular endoprosthesis at 1 and 2 years.

Animals↗
PubMed1988

Biological performance of TiNi shape memory alloy vascular ring prostheses: a two year study.

A method was developed for the noninvasive insertion of a vascular ring prostheses aimed at preserving arterial patency and preventing restenosis following angioplasty. Using a specially designed 7F catheter 22 nitinol (TiNi) wire prostheses (I.D. 5 mm; 0.25 mm thickness) were torsion reduced in diameter and inserted under fluoroscopy into both carotid (n = 2) and iliac-femoral arteries (n = 20) of dogs. Aspirin (650 mg BID) and Persantin (200 mg BID) were given for only 30 days postoperatively. Angiography of all rings at 1, 6, 12 months exhibited excellent biocompatibility and long term patency 91% (20/22) as reported in Trans ASAIO 32:30, 1986. Four rings inserted in the right and left common iliac arteries and femoral artery were followed for up to 2 years and exhibited 100% patency. Angiography demonstrated that the anchorage of the prostheses was stable and the lumen was uniformly covered by a thin neointimal layer of endothelial like cells. The prostheses were patent with no evidence of thrombosis or inflammation. In view of the problem of recurrent stenosis occurring during the healing period after balloon angioplasty (PTA or PTCA), this approach may lead to a new means of clinical intervention in atherosclerosis.

Alloys↗
PubMed1987

Recombinant human tumor necrosis factor-alpha: evidence of an indirect mode of antitumor activity.

The antitumor activity of recombinant human tumor necrosis factor (rTNF-alpha) was examined on murine tumors in mice and in cultured cells in vitro. Mice were implanted intradermally with Meth A fibrosarcoma (Meth A) on day 0. rTNF-alpha caused tumor necrosis and inhibited the tumor growth when given i.v. on day 7 or 10, but not when given on day 3. When rTNF-alpha was given i.v. in doses of 0.1-3.2 micrograms/mouse twice a week for 3 weeks beginning on day 7 or 11, the growth of solid Meth A, Colon 26 adenocarcinoma, Colon 38 carcinoma, Sarcoma-180, and M5076 reticulum cell sarcoma tumors implanted s.c. or intradermally was markedly inhibited, and the life of the mice bearing these tumors, except M5076 reticulum cell sarcoma, was prolonged. The growth of Meth A implanted i.m. was also markedly inhibited by rTNF-alpha given i.v. However, the life of mice bearing i.p. Colon 26 adenocarcinoma, MH134 hepatoma, Sarcoma-180, and Ehrlich carcinoma was not prolonged by rTNF-alpha given i.p. nine times (days 1-9) in doses up to 1.0 or 3.2 micrograms/mouse. Only in the case of mice bearing i.p. Meth A, the life was slightly prolonged by i.p. treatment with rTNF-alpha but not by i.v. treatment. In experiments against in vitro cultured cells, rTNF-alpha did not show any direct cytotoxicity against mouse tumor cells: Meth A, Colon 26 adenocarcinoma, Colon 38 carcinoma, and Sarcoma-180, but had a cytotoxic effect against L929 mouse fibroblast. The results suggest that rTNF-alpha is a unique antitumor drug with potent necrotizing activity against solid tumors in mice, and that this activity may derive from indirect mechanisms related to the growth of tumors and not to the direct cytotoxicity of the drug.

Adenocarcinoma↗
PubMed1987

Cell proliferation kinetics of cultured human keratinocytes and fibroblasts measured using a monoclonal antibody.

Measurements of cell cycle kinetics using an immunoperoxidase method employing monoclonal anti-bromodeoxyuridine (BrdU) antibody were compared with an autoradiographic method using [3H]-thymidine. The methods were applied to epithelial cells grown from explants of normal skin and basal cell carcinoma (BCC), and to fibroblasts from normal skin, hypertrophic scar and keloid. In normal keratinocytes the number of peroxidase-positive cells was higher than the number incorporating [3H]-thymidine, because of the presence of labelled cells in the centre of the explants in the former. The epithelial cells from BCC gave a mean (+/- SD) of 4.9 +/- 1.2% peroxidase-positive cells, while no cells were labelled with [3H]-thymidine. In dermal fibroblasts from normal skin and hypertrophic scar the percentages of peroxidase-positive cells did not differ significantly from the [3H]-thymidine labelling indices. The immunological method has advantages over [3H]-thymidine autoradiography in that it avoids radioactive material and the proportion of cells labelled by the two methods is the same.

Antibodies, Monoclonal↗
PubMed1987

Growth kinetics of fibroblasts derived from normal skin and hypertrophic scar.

In vitro growth kinetics of fibroblasts derived from normal skin and hypertrophic scar were performed using continuous 3H-thymidine labeling method. In fibroblasts derived from normal skin, aging of the donor affects cell growth mainly by growth fraction (GF), but not labeling index (LI) and DNA synthetic time (Ts). When hypertrophic scar-derived fibroblasts are compared with normal fibroblasts, they showed a shorter Ts and lower LI and GF. This result suggests that in hypertrophic scar a small number of fibroblasts proliferate more actively, but most fibroblasts are non-growing cells.

Adolescent↗