Katsutoshi Miyauchi

Protective Effects of Anti-Neutrophil Antibody against Myocardial Ischemia/Reperfusion Injury in Rats

Neutrophil activation initiates myocardial ischemia/reperfusion (I/R) injuries. The aim of this study is to evaluate the in vitro functions of an anti-neutrophil monoclonal antibody, Urge-8, and its therapeutic efficacy against myocardial ischemia (MI) in rats. We measured in vitro functions of rat neutrophils including chemotactic activity, superoxide production, phagocytic function, and neutrophil degranulation. MI was induced in Wistar rats by clamping the left coronary artery for 1 h. Rats received either isotype-negative control IgG1 (control group, n = 20), 250 µg/kg of Urge-8 before (pre-treatment group, n = 20) or after (post-treatment group, n = 20) MI. The three groups were compared during the first 24 h after reperfusion with respect to changes in mean arterial pressure, heart rate, body temperature, biochemistry, serum cytokines, myocardial neutrophil infiltration, survival rate, and size of MI. Urge-8 effectively suppressed in vitro functions of rat neutrophils including chemotactic activity, superoxide production, phagocytic function, and neutrophil degranulation. The Urge-8 treated groups showed higher levels of arterial pressure and survival rate, lower values of interleukin-6 and interleukin-8, lower grade of myocardial neutrophil infiltration, and smaller MI size as compared to the control group. In conclusion, Urge-8 is effective against myocardial I/R injury by suppressing certain functions and myocardial infiltration of neutrophils in rats.

Therapeutic efficacy of an antineutrophil monoclonal antibody, Urge-8, against acute necrotizing pancreatitis in rats

BACKGROUND Although they have critical roles in the defense mechanism against invading microorganisms, neutrophils may facilitate exacerbation of critical conditions associated with acute necrotizing pancreatitis by a discharge of granule contents into the organ tissues. Because of this constitution of neutrophils, the therapeutic efficacy of Urge-8, a mouse monoclonal antibody to neutrophils, on the survival of rats with experimentally induced acute necrotizing pancreatitis was investigated in vivo. METHODS Acute pancreatitis was induced by injection of trypsin mixed with sodium chenodeoxycholic acid into pancreatic ducts. Urge-8 was infused intravenously 30 minutes after pancreatitis was induced, a series of vital signs was taken, and plasma amylase level was estimated. RESULTS Hemorrhagic necrosis of the pancreas and intraabdominal bleeding were observed 1 hour after the pancreatitis-inducing drugs were injected, and death occurred at 240.9 +/- 24.6 minutes (mean +/- SD)in the control group. With Urge-8 administration, however, the survival time was significantly prolonged to 395.2 +/- 64.4 minutes (p = 6.0 x 10-(10) versus control). Failure in the vital signs (mean arterial pressure, heart rate, and body temperature) was significantly ameliorated by injection of Urge-8. The plasma amylase level was elevated after pancreatitis was induced and peaked at 3 hours (4915 +/- 1966 IU/L in mean +/- SD). This level was suppressed during the first 3 hours by injection of Urge-8 (3372 +/- 1223 IU/L); however, the amylase level increased thereafter, becoming comparable with the peak in the control group, and then death occurred. Arterial blood gas and plasma electrolyte analyses showed that pH, base excess, and plasma potassium levels in the group treated with monoclonal antibody were significantly improved. CONCLUSIONS It was suggested that neutrophils play some critical role in the exacerbation of acute necrotizing pancreatitis and its related symptoms. Although not capable of preventing death in our model, treatment with the antineutrophil monoclonal antibody Urge-8 after the onset of acute pancreatitis prolonged the survival time significantly.

Ischemia of the intestinal mucosa during cardiopulmonary bypass.

Abstract Bacterial translocation is believed to occur during cardiopulmonary bypass (CPB) because serum endotoxin concentrations rise. Intestinal ischemia during CPB, however, has never been proven directly. The condition of the intestinal mucosa during CPB was studied by measuring serum diamine oxidase (DAO) activity, an index of intestinal ischemia. Serum DAO activity, blood lactate concentration, and the arterial ketone body ratio (AKBR) were measured intraoperatively in four successive patients who underwent aortic arch replacement by the open distal anastomosis method. DAO activity rose after restoration of blood flow to the lower half of the body, and continued to rise throughout CPB. The lactate concentration also rose, mirroring the change in DAO activity, and returned to nearly normal 12 h after the operation. The AKBR decreased during CPB, with a mean minimum vale of 0.16 ± 0.07 immediately after the restoration of blood flow to the lower half of the body. The parallel rise in DAO activity and serum lactate concentration once blood flow to the lower half of the body was restored implies that ischemic injury to the mucosa of the small intestine occurs during CPB. The continued rise in these parameters throughout CPB is consistent with ongoing injury due to splanchnic hypoperfusion, as reflected in the decrease in the AKBR during the same period.

The effect of combination splenectomy and low-dose FK506 therapy on graft survival after liver allograft transplantation in rats

The effect of splenectomy on allograft survival was investigated using orthotopic liver transplantation in a rat experimental model (ACI rat liver grafted to LEW rat). Control rats without any immunosuppressive treatment died, on average, 10.4 +/- 1.4 days after operation. Splenectomy alone somewhat prolonged the survival (13.4 +/- 2.0 days), and low-dose FK506 therapy moderately prolonged it (22.7 +/- 7 days). The graft survival period was significantly prolonged (39.7 +/- 6.3 days) when them two treatments were combined. The elevation of cytotoxic antiallograft antibodies was suppressed by splenectomy but not by low-dose FK506 therapy. The development of jaundice was moderately suppressed by FK506 but not by splenectomy. There was no difference between the pattern of body weight decline in either of them two groups and that in control rats. When these two treatments were combined at the same time, the elevation of cytotoxic antibodies, development of jaundice and decline of body weight were suppressed. These data indicate that B cells play an important role in the acute rejection of the rat liver allograft at least partially via production of cytotoxic antiallograft antibody. Splenectomy or other immunosuppressive methods affecting B cells can be a supplement for immunosuppression when using reduced-dose FK506.

Pitavastatin Prevents Bacterial Translocation after Nonpulsatile/Low-Pressure Blood Flow in Early Atherosclerotic Rat: Inhibition of Small Intestine Inducible Nitric Oxide Synthase

Background: Cardiopulmonary bypass decreases intestinal mucosal blood flow because of nonpulsatile and low-pressure blood flow resulting in bacterial translocation (BT) and atherosclerosis also has peripheral blood flow deficiency. The risk of nonpulsatile and low-pressure blood flow for atherosclerotic animals and the effect of statin administration, which has pleiotropic effects, were studied. Methods: Wistar rats were divided into four groups: group N (normal diet), group C (high-cholesterol diet), group S (group C plus pitavastatin therapy), and group I [group C plus inducible nitric oxide (iNOS) inhibitor therapy]. First of all, vascular responses were measured. Then the rats underwent nonpulsatile/low-pressure blood flow in the intestine, and the serum peptidoglycan concentration as a parameter of BT, the small intestinal PO2 ratio (intestinal PO2/PaO2) as a parameter of mucosal blood flow, and NO concentrations were measured before surgery (T0), at the end of 90 min of stenosis (T1), and 90 min after the release of stenosis (T2). Immunostaining for nitrotyrosine was also performed at T2. Results: Group C had vascular endothelial dysfunction without histological changes, which indicated early atherosclerosis. The serum peptidoglycan concentration increased significantly at T2 only in group C. The intestinal PO2 ratio was decreased at T1 in all the groups, and retuned to baseline at T2 in group N and group S, but not in group C or group I. Jejunal NO only in group C was significantly higher at all time points and ileal NO production at T1 and T2. There tended to be a positive stain for nitrotyrosine along the mucosal epithelium in group C. Conclusion: In the setting of early atherosclerosis, intestinal blood flow does not only improve after nonpulsatile/low-pressure blood flow but causes BT because of a large amount of NO from high enzymatic intestinal iNOS activity, and pitavastatin treatment can prevent BT by improving both issues.

Prenatally detected cystic adrenal neuroblastoma

Routine US for term pregnancy identifi ed a male fetus with an intra-abdominal cystic lesion. The 2846 g boy was born by normal vaginal delivery at 40 weeks, with an Apgar score of 9. He was referred to Ehime University Hospital because postnatal US indicated a right adrenal cystic mass. Findings on physical examination were normal. Urinary vanillylamandelic acid (VMA), urinary homovanillic acid (HVA), and serum neuronspecifi c enolase (NSE) were within normal ranges. Computed tomography (CT) 2 weeks later showed a 4 cm multicystic lesion located suprarenally on the right side, with a small solid component ( Fig. 1 ). There were no fi ndings suggestive of metastasis to lymph node or liver. At 27 days old the patient underwent laparotomy because neuroblastoma could not be excluded. The mass was present in the right adrenal gland, displaying a smooth surface and no infi ltration of the surrounding tissue. Tumor excision including the right adrenal gland was performed. The multilocular tumor measured 3.5 × 2.5 × 2.5 cm and contained hemorrhagic material. Histological examination showed the cyst to be lined with a thick fi brous wall, which contained a proliferation of small round tumor and adrenal gland cells ( Fig. 2 ). The tumor cells were diagnosed as poorly differentiated neuroblastoma, of rosette-fi brillary type. Histological appearance was favorable with low mitosis – karyorrhexis index according to the Shimada classifi cation. 7 The patient had favorable biological markers, including no amplifi cation of N-myc, and expression of Ha-ras (2+) and Trk A (3+). Bone scintigraphy after operation showed no metastasis and so the tumor was staged as I. Postoperative course was uneventful and the patient is doing well at 3 years of age. Discussion

Immediate localization using ultrasound-guided hookwire marking of peripheral lung tumors in the operating room.

A new method of marking peripheral lung tumors using an ultrasound-guided hookwire has been developed. The procedure was done for nine tumors taking 15-20 min for each method in the operating room; all of them had no complications. In eight cases (89%), the wire tips were shown to be located within the tumor itself or within 5 mm from the targets, close enough to support appropriate surgery. Ultrasound-guided hookwire marking of peripheral tumors can provide appropriate guidance and prove effective in immediately facilitating subsequent thoracoscopic resection.

Cardiac surgery in patients with end-stage renal disease. Utility of continuous ambulatory peritoneal dialysis.

OBJECTIVES The number of patients with end-stage renal disease undergoing open heart surgery continues to grow. We evaluated continuous ambulatory peritoneal dialysis and the extracorporeal ultrafiltration method during cardiopulmonary bypass in the management of these difficult patients. METHODS These 2 methods were used in 4 patients with renal failure who underwent open heart surgery between July 1997 and March 1999. Preoperative continuous ambulatory peritoneal dialysis was conducted using standard protocols. Extracorporeal ultrafiltration method was used only during cardiopulmonary bypass. Continuous ambulatory peritoneal dialysis was initiated upon arrival at the intensive care unit. Mean follow-up was 12 months. RESULTS Postoperative blood urea nitrogen and creatinine concentrations were lower than preoperative concentrations. No patients required hemodialysis. All 4 patients were discharged to their homes. No deaths occurred. CONCLUSIONS Continuous ambulatory peritoneal dialysis and extracorporeal ultrafiltration method are combined to treat patients with end-stage renal disease who require open heart surgery. This combination is simple, and does not require specialized personnel, and obviates the hemodynamic instability associated with hemodialysis.