Abstract. Tetrahydrobiopterin (BH4) acts as an essential cofactor for the enzymatic activity of nitric oxide (NO) synthases. Biosynthesis of the cofactor BH4 starts from GTP and requires 3 enzymatic steps, which include GTP cyclohydrolase I (GCH I) catalysis of the first and ratelimiting step. In this study we examined the effects of cGMP on GCH I activity in human umbilical vein endothelial cells under inflammatory conditions. Exogenous application of the cGMP analogue 8-bromo-cGMP markedly inhibited GCH I activity in the short term, whereas an cAMP analogue had no effect on GCH I activity under the same condition. NO donors, NOR3 and sodium nitroprusside, elevated the intracellular cGMP level and reduced GCH I activity in the short term. This inhibition of GCH I activity was obliterated in the presence of an NO trapper carboxy-PTIO. NO donors had no effect on GCH I mRNA expression in the short term. Moreover, cycloheximide did not alter the inhibition by NO donors of GCH I activity. These findings suggest that stimulation of the cGMP signaling cascade down-regulates GCH I activity through post translational modification of the GCH I enzyme.

Profunda femoris artery aneurysms (PFAAs) are rare and difficult to diagnose in the early stage. They are often found due to the presence of complicated conditions, such as rapid expansion, rupture, or acute lower limb ischemia. Surgical procedures such as aneurysmectomy and endoaneurysmorrhaphy tend to be technically challenging because of the patient status and the extent of the aneurysm. We experienced three cases of PFAAs that were treated by proximal ligation (PL) without complete control of the distal branches. The exclusion of PFAAs was confirmed by duplex ultrasound or angiography at the end of the operation. There was no mortality in the perioperative period. During a 12-month follow-up, all cases exhibited complete exclusion of aneurysms with marked size reduction. Based on these findings, we propose that PL, with a careful follow-up for PFAA exclusion and distal limb circulation, could be an alternative treatment for complicated PFAAs.

Currently available master-slave manipulators cannot recognize the elasticity of organs or tissues. The aim of this study was to examine whether a newly developed haptic forceps using a linear motor could measure the elasticity of living organs using an animal model. We measured the elasticity values and the disruption limit values of rat organs using the new haptic forceps. The elasticity of the materials was calculated using the formula "power / position", with N/m as the unit. We successfully and reproducibly measured the changes in the elasticity values of various materials in real time. We were also able to perceive tactile changes transmitted through the forceps. The changes in gastrointestinal contraction were synchronized with the visually observed changes, and these changes were monitored and measured as elasticity values in real time using the forceps. The damage limits were also successfully measured. In conclusion, the new haptic forceps enabled highly sensitive, real-time measurements of elasticity in living rat organs. The use of this forceps enables the disruption limit values of organs to be measured, and the device could be useful for setting safety limits when grasping organs during endoscopic surgery.

Leiomyoma is the most common submucosal tumor of the esophagus, and accurate preoperative diagnosis is diffi cult. We report herein on two resected cases of esophageal leiomyoma preoperatively diagnosed accurately with endoscopic ultrasound-guided fi ne-needle aspiration biopsy (EUS-FNAB). The fi rst patient, a 34-year-old man, had complained of dysphagia. Following EUS-FNAB, the pathological diagnosis was leiomyoma. Esophagectomy and reconstruction with a gastric tube were performed because the tumor had almost completely encircled the esophageal wall. The second patient, a 60-year-old woman, had complained of dysphagia. Following EUS-FNAB, the pathological diagnosis was leiomyoma. Enucleation of the tumor was performed because the tumor was not located in the entire circumference of the esophageal wall. The postoperative course of both patients was uneventful, and the fi nal pathological diagnosis of each case was leiomyoma. We conclude that EUS-FNAB is a useful method for diagnosing esophageal submucosal tumors and for selecting an appropriate surgical procedure.

A case of giant esophageal epiphrenic diverticulum resected laparoscopically, followed by Heller myotomy and Dor fundoplication Abstract A 66-year-old male patient visited our hospital with the chief complaints of diffi culty in swallowing and vomiting. The upper gastrointestinal radiographic contrast study revealed a diverticulum with a diameter of about 10 cm in the diaphragm to the right of the esophagus. Upper gastrointestinal endoscopy revealed the inlet of the diverticulum on the right wall of the esophagus at a distance of 44-46 cm from the incisors. The patient was diagnosed as having a giant epiphrenic esophageal diverticulum with obstruction; dysfunction of the lower esophageal sphincter was also considered. Therefore, he was treated by laparoscopic resection of the diverticulum, followed by Heller myotomy and Dor fundoplication. The postoperative course was satisfactory, and the patient showed substantial improvement in his dysphagia. He was discharged from our hospital on the 9th postoperative day. At present, 2 years after the operation, he remains well without any recurrence of the symptoms.