Hemostatic Capability of a Novel Tetra-Polyethylene Glycol Hydrogel.

BACKGROUND: TetraStat is a tetra-armed polyethylene glycol (PEG) hydrogel. It is a synthetic sealant that solidifies instantly in response to pH changes. This study aimed to evaluate the hemostatic effect of TetraStat through experiments evaluating future clinical applications. METHODS: We used TetraStat, oxidized regenerated cellulose (SURGICEL®), and fibrinogen and thrombin sealant patch (TachoSil®) using in vitro and in vivo experiments. For the in vitro experiment, a closed circulatory system filled with phosphate-buffered saline under high pressure was used. Needle punctures were created and closed using the various sealants. For the in vivo experiment, rat venae cavae were punctured with 18- and 20-gauge (G) needles, and hemorrhage was allowed to occur for several seconds. A porous PEG sponge soaked with TetraStat was applied as a hemostatic system. Hemostasis outcomes were compared among the various concentrations (40-100 g/L) of TetraStat, SURGICEL, and TachoSil. RESULTS: The punctured holes in the prosthetic graft were successfully sealed with TetraStat in 1 min. The success rate of hemostasis with TetraStat for the punctured holes in the rat vena cava was dose-dependent. TetraStat was effective in sealing the holes created with a 20 G needle at all concentrations; however, the holes created with an 18 G needle could be sealed only when the concentration ≥60 g/L. Hemostasis using SURGICEL or TachoSil was less successful and sometimes required up to 5 min. CONCLUSIONS: TetraStat has a high hemostatic ability. A porous PEG sponge soaked with TetraStat is a useful choice for effective hemostasis during massive hemorrhage.

High aneurysm wall enhancement values are associated with late sac shrinkage after endovascular repair of abdominal aortic aneurysms.

ABSTRACT: To analyze the correlation between aneurysm wall enhancement (AWE) values and early and late sac shrinkage after endovascular aneurysm repair (EVAR).We retrospectively analyzed 28 patients who underwent EVAR for abdominal aortic aneurysms (AAA) using a bifurcated main body stent graft. The value of AWE in the slice of the maximum AAA diameter was measured using a volumetric analysis of computed tomography images. Sac measurements before EVAR and more than 10 months after EVAR were compared, and the maximum sac shrinkage rate was calculated.The AWE value immediately after (4 to 7 days) EVAR correlated positively with the sac shrinkage rate (R2 = 0.0139). The AWE value at 6 months after EVAR was also strongly correlated with the sac shrinkage rate (R2 = 0.4982).Higher AWE values at 6 months after EVAR were strongly associated with the sac volume shrinkage rate. High AWE values may be a predictive factor for sac shrinkage and may aid in the selection of the appropriate clinical strategy after EVAR.

Giant insulinoma: report of a case and review of published reports.

BACKGROUND: Larger insulinomas are reportedly more likely to be malignant; however, their biological behavior has not been clearly elucidated. We here report the characteristics and treatment of a giant insulinoma with local invasion and lymph node metastasis. We also review published reports concerning the clinical features of giant insulinomas and comparing their grading with that of pancreatic neuroendocrine tumors. CASE PRESENTATION: A 71-year-old man was referred to our hospital for investigation of persistent hypoglycemia. On the current presentation, laboratory tests showed serum glucose, immunoreactive insulin, and C peptide concentrations of 45 mg/dL, 17.2 µIU/mL and 4.1 ng/mL, respectively. Dynamic magnetic resonance imaging showed a hypervascular tumor measuring 13.5 cm in the head of the pancreas. Computed tomography scanning demonstrated local invasion and lymph node involvement. He thus had Whipple's triad, which is associated with malignant insulinoma. No distant metastases having been identified, pancreaticoduodenectomy was performed. Intraoperatively, three separate tumors were identified in the pancreatic head. Pathological examination showed all three tumors were pancreatic neuroendocrine tumors; the tumor cells in the largest mass were strongly immunoreactive for insulin. The Ki-67 index was 2-5% in most parts of the largest tumor and over 20% in the poorly differentiated areas. This tumor was classified as neuroendocrine carcinoma in accordance with the 2010 World Health Organization classification of pancreatic endocrine neoplasms. He remains free of evidence of recurrence 2 years postsurgery. A review of published reports indicated that giant insulinomas are more malignant than smaller ones, and metastatic disease is found on presentation in 56% of patients with giant insulinomas; however, we were unable to identify any correlation between grade of pancreatic neuroendocrine tumor and biological behavior of giant insulinomas. CONCLUSIONS: Giant insulinomas more frequently exhibit malignant behavior, such as local invasion, lymph node involvement, and liver metastasis, than smaller ones. However, there was no relationship between grade and rate of metastases or survival in this small case series. Identification of useful biological markers is necessary.

Primary gastrointestinal stromal tumor of the liver: a case report and review of the literature.

BACKGROUND: Recently, gastrointestinal stromal tumors that have developed outside of the digestive tract have been reported. These tumors are collectively termed extra-gastrointestinal stromal tumors. Extra-gastrointestinal stromal tumors can also develop in the liver. Only eight case reports involving primary GIST of the liver have been published. We report a case and review the literature regarding this disease. CASE PRESENTATION: A 70-year-old woman with a past history of gastric cancer visited our hospital for regular inspection. With extensive radiological imaging, a computed tomography scan revealed a mass with a size of 6.8 cm in the lateral segment of the liver. (18)F-Fluoro-2-deoxyglucose positron emission tomography revealed no other malignancies except for the liver tumor. Because the lesion was suspected of being a primary malignant hepatic tumor, lateral segmentectomy was performed. The immunohistochemical analysis supported the diagnosis of gastrointestinal stromal tumors in the liver. The patient has had no evidence of recurrence during the 10-month follow-up period; imatinib chemotherapy was not administered. CONCLUSIONS: Primary hepatic gastrointestinal stromal tumors had no characteristics that distinguished them from ordinary tumors in imaging examinations. Primary gastrointestinal stromal tumors might have developed from interstitial Cajal-like cells.