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Featured researches published by Masaaki Aiba.


Surgery Today | 1999

Induction of a critical elevation of povidone-iodine absorption in the treatment of a burn patient: report of a case.

Masaaki Aiba; Jun Ninomiya; Kazushige Furuya; Hiroshi Arai; Hitoshi Ishikawa; Shuuichirou Asaumi; Atuhiko Takagi; Susumu Ohwada; Yasuo Morishita

A critical elevation of povidone-iodine absorption which occurred in a burn patient who was topically treated with 10% povidone-iodine (PI) gel is herein reported. A 65-year-old man was admitted to our hospital for deep second-and third-degree burns covering 26% of his total body surface area. The intravenous administration with lactated Ringer’s solution and topical treatment with silver sulfadiazine were applied in addition to such treatments as debridement and skin grafting. However, wound infection occurred due toPseudomonas aeruginosa. Topical treatment with PI gel was effective for this condition. Persistent nodal bradycardia with hypotension, metabolic acidosis, and renal failure occurred 16 days after the start of PI gel treatment. Iodine toxicosis caused by PI gel was suspected with a serum iodine level of 20 600 μg/dl (normal range 2–9 μg/dl). The PI gel treatment was therefore discontinued immediately, and hemodialysis was scheduled. However, the patient’s family refused hemodialysis and he died 44 days after admission. To our knowledge, only eight patients with iodine toxicosis have been reported in burn patients treated with PI gel.


Digestive Diseases and Sciences | 1999

Effect of FR167653 on Small Bowel Ischemia-Reperfusion Injury in Dogs

Izumi Takeyoshi; Kotaro Iwanami; Susumu Ohwada; Yoshiyuki Kawashima; Kiyoshi Kawata; Masaaki Aiba; Junya Kobayashi; Toru Koyama; Koshi Matsumoto; Susumu Satoh; Yasuo Morishita

IL-1 and TNF-α are known to be pleiotropiccytokines associated with various inflammatoryconditions such as small intestinal injury afterischemia-reperfusion. FR167653 has been characterized asa potent suppressant of IL-1 and TNF-αproduction. The effect of FR167653 on intestinalreperfusion injury was investigated in a warm ischemiamodel of the canine gut. Sixteen mongrel dogs weredivided into two groups: a control group and a FR groupto which FR167653 was administered. Both the superiormesenteric artery and vein were clamped for 2 hr.Arterial pH, hepatic venous hemoglobin oxygensaturation, intramucosal pH, and the survival rate werewell maintained in the FR group in comparison with thecontrol group after reperfusion. FR167653 inhibited theexpression of IL-1β mRNA. Histologically,ischemia-reperfusion injury was more severe in the control groupthan the FR group. This study suggests that FR167653inhibits proinflammatory cytokines and amelioratesischemia-reperfusion injury of the smallintestine.


Journal of The American College of Surgeons | 2001

Novel nitric oxide donor (FK409) ameliorates liver damage during extended liver resection with warm ischemia in dogs.

Masaaki Aiba; Izumi Takeyoshi; Susumu Ohwada; Yoshiyuki Kawashima; Kotaro Iwanami; Yutaka Sunose; Tatsuya Yamada; Hirofumi Tsutsumi; Koshi Matsumoto; Yasuo Morishita

BACKGROUND Nitric oxide attenuates ischemia-reperfusion injury by maintaining organ circulation through its actions as a vasoregulator, an inhibitor of platelet aggregation, and an attenuator of leukocyte adhesion. Otherwise, the harmful effects of enhanced nitric oxide production induced by inducible nitric oxide synthase mediate ischemia-reperfusion injury. FK409 has been characterized as a spontaneous nitric oxide donor. The aim of this study was to evaluate the effects of FK409 on extended liver resection with ischemia using a canine model. STUDY DESIGN Adult mongrel dogs were subjected to 60 minutes of warm ischemia by partial inflow occlusion. After reperfusion the nonischemic lobes were resected and the remnant liver function was evaluated. The dogs were divided into two groups: the control group (n = 7) and the FK409 group (n = 6), which was given FK409 through the portal vein. RESULTS The hepatic tissue blood flow, serum liver enzymes levels, and serum endothelin-1 level after reperfusion were significantly better in the FK409 group than in the control group. Electron microscopy demonstrated that endothelial cells and Ito cells were well-preserved in the FK409 group. The 3-day survival rate was statistically better in the FK409 group (67%) than in the control group (14%). CONCLUSIONS FK409 appears to have protective effects during extended liver resection with ischemia.


Digestive Diseases and Sciences | 2001

A Spontaneous Nitric Oxide Donor Ameliorates Small Bowel Ischemia–Reperfusion Injury in Dogs

Kiyoshi Kawata; Izumi Takeyoshi; Kotaro Iwanami; Yutaka Sunose; Masaaki Aiba; Susumu Ohwada; Koshi Matsumoto; Yasuo Morishita

Nitric oxide (NO) appears to play an important role in tissue injury during reperfusion. FK409 is the first spontaneous NO donor that increases plasma guanosine 3`,5`-cyclic monophosphate. We investigated the effects of the NO donor FK409 (FK) on ischemia–reperfusion injury in a canine warm ischemia model. Fourteen adult mongrel dogs were divided into two groups: the control group and the FK group, which received FK. The superior mesenteric artery and vein were both clamped for 2 h and then reperfused for 12 h. Arterial and intramucosal pH were well maintained in the FK group in comparison with the control group. Histologically, ischemia–reperfusion injury was significantly more severe in the control group than in the FK group. The serum NO levels were significantly higher in the FK group than in the control group during FK administration. FK409 has protective effects on ischemia–reperfusion injury of the small intestine due to NO release.


Journal of Heart and Lung Transplantation | 2000

The effect of FK409—a nitric oxide donor—on canine lung transplantation

Yutaka Sunose; Izumi Takeyoshi; Susumu Ohwada; Shigeru Iwazaki; Masaaki Aiba; Naoki Tomizawa; Hirofumi Tsutsumi; Noboru Oriuchi; Koshi Matsumoto; Yasuo Morishita

BACKGROUND Nitric oxide (NO) is known to have beneficial effects in ischemia-reperfusion (I/R) injury through maintaining endothelial integrity, inhibiting leukocyte adhesion and platelet aggregation, and inducing vasodilation. The effect of FK409 (FK), a spontaneous NO donor, was investigated in a canine lung transplantation model. METHODS Ten pairs of weight-matched dogs were used. Five pairs were assigned to the FK group, to which FK (5 microg/kg/min) was administered intravenously from 30 minutes prior to ischemia until the induction of ischemia in the donor, and from 15 minutes prior to reperfusion until 45 minutes after reperfusion in the recipient. The others were assigned to the control group. After 8-hour preservation in 4 degrees C Euro-Collins solution, orthotopic single-lung transplantation was performed. During a 5-minute clamping test of the right pulmonary artery, left pulmonary arterial pressure (L-PAP), left pulmonary vascular resistance (L-PVR), arterial oxygen pressure (PaO(2)), and alveolar-arterial oxygen pressure difference (A-aDO(2)) were measured. The lung specimens were harvested for histologic study, and polymorphonuclear neutrophils (PMNs) were counted. Pulmonary perfusion and ventilation scintigraphy (Tc-99m-MAA and Xe-133) were performed. RESULTS PAP, L-PVR, PaO(2), and A-aDO(2) revealed significantly (p < 0.05) better function in the FK group than in the control group. Histologically, edema was more mild, and PMN infiltration was significantly (p < 0.05) lower in the FK group than in the control group. Xe-133 and Tc-99m-MAA were widely distributed throughout the graft lung in the FK group. The 2-day survival rate was 100% in the FK group, which was significantly (p < 0.05) better than the rate (40%) in the control group. CONCLUSIONS FK appears to generate a protective effect on I/R injury in lung transplantation.


Journal of Heart and Lung Transplantation | 2000

FR167653 ameliorates pulmonary damage in ischemia-reperfusion injury in a canine lung transplantation model

Masaaki Aiba; Izumi Takeyoshi; Yutaka Sunose; Shigeru Iwazaki; Hirofumi Tsutsumi; Susumu Ohwada; Naoki Tomizawa; Noboru Oriuchi; Koshi Matsumoto; Yasuo Morishita

BACKGROUND Interleukin (IL)-1 and tumor necrosis factor-alpha (TNF-alpha) are recognized as important factors in ischemia-reperfusion (I/R) injury. FR167653 has been characterized as a potent suppressant of IL-1 and TNF-alpha production. We previously reported that FR167653 suppressed the expression of IL-1 beta mRNA after reperfusion and ameliorated pulmonary I/R injury following 3-hour left lung warm ischemia in dogs. The aim of this study was to investigate the effects of FR167653 on I/R injury in a canine left, single, lung transplantation model. METHODS We used 10 pairs of weight-matched dogs. We assigned 5 pairs to the FR group, in which each animal received FR167653 (1 mg/kg/hr) IV from 30 minutes before ischemia until 2 hours after reperfusion; we treated the transplanted lungs with FR167653 after the onset of reperfusion. The others were assigned to the control group. After 8-hour preservation with 4 degrees C Euro-Collins solution, orthotopic left, single, lung transplantation was performed. During a 5-minute clamping test at the right pulmonary artery of each recipient, the left (transplanted) pulmonary arterial pressure (L-PAP), left (transplanted) pulmonary vascular resistance (L-PVR), arterial oxygen pressure (PaO(2)), and alveolar-arterial oxygen pressure difference (A-aDO(2)) were measured. We harvested transplanted lung specimens for histologic study, and we counted polymorphonuclear neutrophils (PMNs), which were identified by staining with naphthol AS-D cholroacetate esterase. Pulmonary perfusion and ventilation scintigraphy (Tc-99m-MAA and Xe-133) were performed. We observed the animals for 3 days after transplantation. RESULTS The PAP, L-PVR, PaO(2), and A-aDO(2) revealed significantly (p < 0.05) better function in the FR group than in the control group. Histologically, lung edema was milder, and PMN infiltration was significantly (p < 0.05) lower in the FR group than in the control group. Xe-133 and Tc-99m-MAA were widely distributed throughout the graft lung in the FR group. Three-day survival rates in FR and control groups were 60% and 20%, respectively. CONCLUSIONS FR167653 appears to generate a protective effect on I/R injury in lung transplantation in dogs.


International Journal of Angiology | 2001

FR128998 (a PAF receptor antagonist) counters the increased pulmonary vascular resistance associated with ischemia-reperfusion injury in the canine lung

Shigeru Iwazaki; Izumi Takeyoshi; Susumu Ohwada; Yutaka Sunose; Masaaki Aiba; Hirofumi Tsutsumi; Yoshiyuki Kawashima; Koshi Matsumoto; Yasuo Morishita

Ischemia-reperfusion injury induces deterioration of pulmonary function following lung transplantation. The spiro-thiazepin derivative FR128998 (FR) is a novel PAF receptor antagonist. The effect of FR on ischemia-reperfusion injury was investigated in anin situ warm ischemia model of canine lungs. Fifteen adult mongrel dogs, weighing 6 to 12 kg, were divided into two groups. FR (1 mg/kg/hr) was administered from prior to ischemia until 2 hours after reperfusion (FR-treated group; n=8), or vehicle was injected using the same technique (Control group; n=7). Following hilar stripping of the left lung, the left pulmonary artery and veins were clamped for 3 hours to induce warm ischemia. The left main bronchus was bisected at the same time and anastomosed 3 hours later. Arterial oxygen saturation (SaO2), left pulmonary vascular resistance (L-PVR), and cardiac output (CO) were measured 30 minutes after reperfusion. The lungs were harvested for pathological study, and polymorphonuclear neutrophils (PMNs) were counted. The 2-day survival rate was also investigated. After reperfusion, SaO2 L-PVR, and CO were significantly (p<0.05) better in the FR-treated group than in the control group. Histological findings after 30 minutes of reperfusion showed alveolar damage with interstitial edema and hyaline membranes localized along the alveolar ducts in the control group, while there was only slight localized interstitial edema in the FR group. PMN infiltration was less extensive in the FR group than in the control group. FR appears to have a protective effect against lung ischemia-reperfusion injury. This might result from inhibition of the local release of PAF.


Surgery Today | 1997

Left ventricular fibroma in an aged patient: Report of a case

Kazuhiro Sakata; Akio Ohtaki; Masaaki Aiba; Susumu Ishikawa; Yoshimi Otani; Yasuo Morishita

We report herein the case of a 77-year-old man with a left ventricular tumor originating from the papillary muscle of the left ventricular wall, in whom a successful tumor resection with mitral valve replacement was performed. The pathological diagnosis of the tumor was confirmed as cardiac fibroma. His postoperative course was uneventful and he is currently well with no signs of recurrence 2 years after surgery.


Journal of The American College of Surgeons | 2000

Optimal end point of FR167653 administration and expression of interleukin-8 messenger RNA on extended liver resection with ischemia in dogs

Masaaki Aiba; Izumi Takeyoshi; Susumu Ohwada; Junya Kobayashi; Kotaro Iwanami; Yutaka Sunose; Yoshiyuki Kawashima; Koshi Mastumoto; M Muramoto; Yasuo Morishita

BACKGROUND FR167653 is a potent suppressant of interleukin-1 and tumor necrosis factor production. We previously reported that FR167653 inhibited the expression of interleukin-1 messenger RNA (mRNA) after ischemia-reperfusion and provided a protective effect against ischemia-reperfusion injury after extended liver resection. In this study we investigated the optimal end point of FR167653 administration and the inhibition of interleukin-8 (IL-8) mRNA expression caused by the administration of FR167653 during extended liver resection with ischemia in a dog model. STUDY DESIGN The right portal pedicle was clamped for 60 minutes but the left portal vein was left patent to avoid portal congestion. After reperfusion 75% of the liver was resected. EXPERIMENT I: Adult mongrel dogs were divided into three groups: the control group (n = 9); the FR-2 group (n = 6), which received FR167653 through the portal vein starting 30 minutes before the onset of ischemia until 2 hours after reperfusion; and the FR-6 group (n = 6), which received FR167653 starting 30 minutes before ischemia until 6 hours after reperfusion. Hepatic venous blood was collected to measure liver enzymes. Liver specimens were harvested for histologic study 6 hours after reperfusion and polymorphonuclear neutrophils were counted. EXPERIMENT II: The expression of IL-8 was measured by reverse-transcriptase polymerase chain reaction. RESULTS Aspartate aminotransferase and alanine aminotransferase levels after reperfusion and hyaluronic acid levels 6 hours after reperfusion were significantly (p < 0.05) lower in the FR-2 and FR-6 groups than in the control group. There were no significant differences between the FR-2 and FR-6 groups after reperfusion. Histologically liver tissue damage was mild in the FR-2 and FR-6 groups, and polymorphonuclear neutrophil infiltration was significantly lower in the FR-2 and FR-6 groups than in the control group. The 3-day survival rate was statistically (p < 0.05) better in the FR-2 and FR-6 groups than in the control group. IL-8 mRNA expression was inhibited in the FR-treated group. CONCLUSIONS FR167653 should be administered until shortly after reperfusion and need not be administered for many hours after reperfusion. FR167653 inhibits IL-8 mRNA production and inhibits polymorphonuclear neutrophil infiltration.


Journal of Surgical Research | 2001

The effect of a selective cyclooxygenase-2 inhibitor in extended liver resection with ischemia in dogs

Izumi Takeyoshi; Yutaka Sunose; Shigeru Iwazaki; Hirofumi Tsutsumi; Masaaki Aiba; Mureo Kasahara; Susumu Ohwada; Koshi Matsumoto; Yasuo Morishita

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