Abstract-Abdominal aortic aneurysm (AAA) is histologically characterized by medial degeneration and various degrees of chronic adventitial inflammation, although the mechanisms for progression of aneurysm are poorly understood. In the present study, we carried out histological study of AAA tissues of patients, and interventional animal and cell culture experiments to investigate a role of mast cells in the pathogenesis of AAA. The number of mast cells was found to increase in the outer media or adventitia of human AAA, showing a positive correlation between the cell number and the AAA diameter. Aneurysmal dilatation of the aorta was seen in the control (ϩ/ϩ) rats following periaortic application of calcium chloride (CaCl 2 ) treatment but not in the mast cell-deficient mutant Ws/Ws rats. The AAA formation was accompanied by accumulation of mast cells, T lymphocytes and by activated matrix metalloproteinase 9, reduced elastin levels and augmented angiogenesis in the aortic tissue, but these changes were much less in the Ws/Ws rats than in the controls. Similarly, mast cells were accumulated and activated at the adventitia of aneurysmal aorta in the apolipoprotein E-deficient mice. The pharmacological intervention with the tranilast, an inhibitor of mast cell degranulation, attenuated AAA development in these rodent models. In the cell culture experiment, a mast cell directly augmented matrix metalloproteinase 9 activity produced by the monocyte/macrophage. Collectively, these data suggest that adventitial mast cells play a critical role in the progression of AAA. Key Words: adventitia Ⅲ inflammation Ⅲ mast cell Ⅲ matrix metalloproteinase Ⅲ aneurysm A bdominal aortic aneurysm (AAA), a relatively common disorder among elderly people, is pathologically characterized by atherosclerosis of the intima and disruption or attenuation of the elastic media with various degrees of adventitial inflammatory infiltration. 1,2 Because approximately 4% of adults older than 65 years harbor AAA, it is among the leading 15 causes of death in elderly persons in the United States. 3 Although substantial efforts have been made to clarify the mechanism of development of AAA, there is currently no effective method to inhibit enlargement of AAA. Repair surgery is necessary to prevent rupture in patients with progressively enlarging AAA, whereas the operative risk is often relatively high because of the other complications resulting from aging.Recent reports suggest that chronic inflammation of the aortic wall and progressive degradation of extracellular matrix proteins are involved in the development, progression, or rupture of AAA. 2,4 -8 As a component of the immune system, mast cells play a critical role in defending hosts against pathogens by releasing a number of immunoregulatory mediators. 9 These cells have also been shown to initiate the inflammatory response by releasing proinflammatory cytokines, growth factors, angiogenic mediators, and proteases, 10 as well as by recruiting other inflammatory cells, such as neutrophils, macrop...

Background Preservation of the spleen in distal pancreatectomy has recently attracted considerable attention. Since our first trial and success with spleen-preserving distal pancreatectomy with conservation of the splenic artery and vein for tumors of the pancreas and chronic pancreatitis, this procedure (Kimura's procedure) has been performed very frequently. Methods The techniques for spleen-preserving distal pancreatectomy (SpDP) with conservation of the splenic artery and vein are clarified. The splenic vein is identified behind the pancreas and within the thin connective tissue membrane (fusion fascia of Toldt). The connective tissue membrane is cut longitudinally above the splenic vein. It is important to remove the splenic vein from the pancreas by working from the body of the pancreas toward the spleen (median approach), because it is very difficult to remove it in the other direction. The pancreas is removed from the splenic artery by proceeding from the spleen toward the head of the pancreas. Results Preservation of the spleen offers various advantages. The maximum platelet levels in blood serum are significantly lower in postoperative patients with splenic preservation than in those with splenectomy. The platelet count was maximal on postoperative day 10 in the 16 patients with SpDP and the count was maximal on postoperative day 13 in the 16 patients with distal pancreatectomy with splenectomy (DPS), and there was a smaller increase in the patients with SpDP than in the patients with DPS. Postoperative bleeding from an ablated splenic artery and vein in SpDP has not been encountered. Either DPS or spleen preservation without preservation of the splenic artery and vein may reduce the blood supply to the residual proximal stomach after distal gastrectomy, which is different from the findings in the Kimura procedure. Conclusion In SpDP, a very slight elevation of the platelet count in serum may help to prevent infarction of the lungs and brain compared to DPS. Another advantage of SpDP performed according to our procedure is that the blood supply to the proximal stomach is conserved in patients with SpDP who undergo distal gastrectomy with resection of the left gastric artery. Benign lesions, as well as low-grade malignancy of the body and tail of the pancreas, may be indications for this procedure. Surgeons should know the techniques and significance of SpDP with conservation of the splenic artery and vein, which is a very safe and reliable method.

Additional PAA might improve the WB and clinical outcomes (especially speed and extent of wound healing) in patients with CLI attributed to infrapopliteal and pedal artery disease.

Background: The aim of this study was to determine the early postoperative hematological changes after spleen-preserving distal pancreatectomy (SpDP) with preservation of the splenic artery and vein (PSAV). Methods: We reviewed 53 patients who underwent SpDP with PSAV (n = 21) or distal pancreatectomy with splenectomy (DPS; n = 32) for benign or low-grade malignant lesions between July 1998 and June 2010. Red and white blood cell (WBC) count, platelet count, serum hemoglobin, hematocrit, C-reactive protein, albumin level, and clinical factors were compared between the SpDP with PSAV and DPS. Results: There were no significant differences in the patient characteristics between the two groups. Platelet count on postoperative day (POD) 5 and WBC count on POD 3 were significantly higher in the DPS group, and these differences continued to be significant until the 3rd month after surgery. Serum hemoglobin and hematocrit in the 1st month after surgery were also significantly higher in the SpDP with PSAV group. Conclusion: The hematological benefits of SpDP with PSAV include reduction of postoperative hematological abnormalities in the early postoperative phase and recovery of the serum hemoglobin and hematocrit levels in the early postoperative phase.

Purpose In the present study, we focused on the accessory middle colic artery and aimed to increase the safety and curative value of colorectal cancer surgery by investigating the artery course and branching patterns. Methods We included 143 cases (mean age, 70.4 ± 11.2 years; 86 males) that had undergone surgery for neoplastic large intestinal lesions at the First Department of Surgery at Yamagata University Hospital between August 2015 and July 2018. We constructed three-dimensional (3D) computed tomography (CT) angiograms and fused them with reconstructions of the large intestines. We investigated the prevalence of the accessory middle colic artery, the variability of its origin, and the prevalence and anatomy of the arteries accompanying the inferior mesenteric vein at the same level as the origin of the inferior mesenteric artery. Results Accessory middle colic artery was observed in 48.9% (70/143) cases. This arose from the superior mesenteric artery in 47, from the inferior mesenteric artery in 21, and from the celiac artery in two cases. In 78.2% (112/143) cases, an artery accompanying the inferior mesenteric vein was present at the same level as the origin of the inferior mesenteric artery; this artery was the left colic artery in 92, the accessory middle colic artery in 11, and it divided and became the left colic artery and the accessory middle colic artery in 10 cases. Conclusion 3D CT angiograms are useful for preoperative evaluation. Accessory middle colic arteries exist and were observed in 14.9% of cases.