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Dive into the research topics where Kenichi Koyano is active.

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Featured researches published by Kenichi Koyano.


Journal of Surgical Research | 1991

Free radical injury in skeletal muscle ischemia and reperfusion

N.A. Choudhury; Shukichi Sakaguchi; Kenichi Koyano; A.F.M. Matin; Hiroyuki Muro

This study was made in a canine isolated gracilis muscle model to measure directly the free radicals, to predict the severity of ischemia and reperfusion injury of the skeletal muscle by measuring its surface pH (mspH), and to determine the effect of Coenzyme Q10 (CoQ10) in reducing the extent of muscle injury. Animals were divided into three groups: group A (control, n = 10), group B (untreated, n = 10), and group C (CoQ10 treated, n = 10). In both groups B and C, 5 hr ischemia followed by 40 min of reperfusion was made. Free radicals were measured directly by electron spin resonance spectrometer (ESR) and mspH was measured using a pH microprobe. Serum creatine phosphokinase (CPK) was estimated before ischemia, 5 and 30 min after reperfusion. The extent of muscle injury was evaluated morphologically by Evans blue dye exclusion test. ESR intensity in group B was 0.55 +/- 0.19 and decreased to 0.30 +/- 0.04 in group C (P less than 0.01). Rate of recovery of mspH was higher in group C (7.16 +/- 0.06) compared to group B (6.88 +/- 0.11, P less than 0.01) and CPK in group C was less (847 +/- 381 IU/liter) than in group B (1356 +/- 519 IU/liter, P less than 0.05) after 30 min of reperfusion. In group C the morphological muscle injury was less (37.8 +/- 5%) compared to group B (56.7 +/- 3.6%, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)


Journal of Computer Assisted Tomography | 1988

Computed tomography of isolated dissecting aneurysm of superior mesenteric artery

Yasuo Takehara; Motoichiro Takahashi; Tetsuaki Fukaya; Masao Kaneko; Kenichi Koyano; Shukichi Sakaguchi

A case of an isolated dissecting aneurysm of the superior mesenteric artery is presented with special references to the findings of CT and angiography. Intimal flaps and the true or false lumina were well identified on thin-section CT with contrast enhancement.


Urology | 1992

EXTENSION INCISION FOR RENAL CARCINOMA INCLUDING INVADED VENA CAVA AND RIGHT LOBE OF LIVER

Shukichi Sakaguchi; S. Hishiki; Satoshi Nakamura; Kenichi Koyano

We report on a thirty-five-year-old woman with renal cell carcinoma who successfully underwent right radical nephrectomy and extended right hepatic lobectomy with resection and reconstruction of inferior vena cava (IVC). A temporary bypass was placed between the infrarenal IVC and right atrium using a heparin-coated synthetic tube. The tumor was resected en bloc including right kidney, adrenal gland, hepatic lobe, and IVC. The IVC was reconstructed using an expanded polytetrafluoroethylene (EPTFE) graft. Her postoperative course was uneventful with no signs of recurrence four years after surgery.


Surgery Today | 2003

Groin infection caused by a percutaneous femoral artery closure device: report of a case.

Naoto Yamamoto; Kenichi Koyano; Masaki Azuma; Hideto Ochiai; Takashi Kashiwabara

Hemostasis after femoral artery catheterization is generally achieved by manual compression, which results in a low incidence of infection at the puncture site. Percutaneous femoral artery closure devices have recently been used to prevent bleeding complications, shorten the hospital stay, and reduce the patients discomfort. However, they have been associated with infectious complications, necessitating surgical intervention, such as patch angioplasty or arterial bypass; the treatment depending on the damage to the artery and the type of device used. Thus, the possibility of infection should be kept in mind when employing these devices. We report a case of groin infection associated with one such device, known as “The Closer,” which was successfully treated by drainage and removal of the suture material.


Surgery Today | 1993

The coexistence of abdominal aortic aneurysm and early gastric cancer : report of three cases

Hiroyuki Konno; Kenichi Koyano; Takashi Hachiya; Satoshi Nakamura; Shozo Baba; Shukichi Sakaguchi

The surgical approach for patients with abdominal aortic aneurysm (AAA) and coexistent abdominal malignancy remains controversial. We report herein three cases of coincident AAA and early gastric cancer, all of whom were treated by a two-stage operation and underwent curative surgery for their gastric cancer. The principles of our surgical approach are as follows: (1) the lesion which requires urgent surgery should be operated on first, and if both lesions show absolute indications, a one-stage surgical procedure should then be performed; (2) a two-stage surgical procedure in which aneurysmectomy is performed first should be undertaken when no absolute indications for urgent surgery exist for either lesion; (3) a one-stage surgical procedure should only be performed when surgery on one lesion makes the other lesion highly dangerous; and (4) in patients with a poor prognosis because of far advanced cancer in whom the AAA shows no sign of rupturing, only a gastrectomy should be performed.


Surgery Today | 1981

Postoperative assessment of arterial reconstructive surgery using Doppler flow detection

Kenichi Koyano; Takashi Kamiya; Shukichi Sakaguchi

The ankle systolic pressure was measured by the Doppler flow detector during the postoperative course after arterial reconstructive surgery in 61 limbs. The ankle systolic pressure was expressed as a pressure index (PI). There were 2 patterns in the recovery of PI after successful reconstructions. In one of these patterns, PI returned to the normal level within 24 hours. The other group represented a delayed recovery of PI. A comparative study between these 2 groups indicated that the delay in the recovery of PI may be chiefly related to a poor distal run-off. There was no relationship between the recovery pattern of PI and the late patency of reconstructed arteries. On the other hand, follow-up examination by means of the ankle pressure measurement was useful to detect new occurrences of stenotic lesions in the postoperative period.


Archives of Surgery | 1990

Hepatic Vein Reconstruction for Preserving Remnant Liver Function

Satoshi Nakamura; Shukichi Sakaguchi; Tadashi Kitazawa; Shouhachi Suzuki; Kenichi Koyano; Hiroyuki Muro


Lasers in Surgery and Medicine | 1989

Microvascular anastomosis using a new diode laser system with a contact probe

Naoki Unno; Shukichi Sakaguchi; Kenichi Koyano


Nihon Rinsho Geka Gakkai Zasshi (journal of Japan Surgical Association) | 2006

A CASE OF CELIAC AXIS COMPRESSION BY MEDIAN ARCUATE LIGAMENT IN WHICH PANCREATICODUODENECTOMY WAS PERFORMED FOR CARCINOMA OF THE PANCREAS HEAD

Takashi Harada; Yoshihiro Yokoi; Kazuhisa Hirayama; Hiroshi Toriyama; Kenichi Koyano


Internal Medicine | 1992

Coronary Artery Disease in Patients with Arteriosclerosis Obliterans of the Lower Extremities or Aortic Aneurysm

Shigeyuki Aoshima; Hong Rong Bang; Naomichi Masuda; Kei Tawarahara; Takahisa Taguchi; Hajime Terada; Masanori Kaneko; Chinori Kurata; Akira Kobayashi; Noboru Yamazaki; Takashi Hachiya; Kenichi Koyano; Shukichi Sakaguchi

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Satoshi Nakamura

Tokyo Institute of Technology

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