Yuichiro Tanishima

Protruding masticatory (superfast) myosin heads from staggered thick filaments of dog jaw muscle revealed by X-ray diffraction

To characterize the structure of jaw muscle fibres expressing masticatory (superfast) myosin, X-ray diffraction patterns of glycerinated fibres of dog masseter were compared with those of dog tibialis anterior in the relaxed state. Meridional reflections of masseter fibres were laterally broad, indicating that myosin filaments are staggered along the filament axis. Compared with tibialis anterior fibres, the peak of the first myosin layer line of masseter fibres was lower in intensity and shifted towards the meridian, while lattice spacings were larger at a similar sarcomere length. These suggest that the myosin heads of masticatory fibres are mobile, and tend to protrude from the filament shaft towards actin filaments. Lowering temperature or treating with N-phenylmaleimide shifted the peak of the first myosin layer line of tibialis anterior fibres towards the meridian and the resulting profile resembled that of masseter fibres. This suggests that the protruding mobile heads in the non-treated masticatory fibres are in the ATP-bound state. The increased population of weakly binding cross-bridges may contribute towards the high specific force of masticatory fibres during contraction. Electron micrographs confirmed the staggered alignment of thick filaments along the filament axis within sarcomeres of masticatory fibres, a feature that may confer efficient force development over a wide range of the sarcomere lengths.

Effects of half-solid nutrients on gastroesophageal reflux in beagle dogs with or without cardioplasty and intrathoracic cardiopexy.

BACKGROUND Percutaneous endoscopic gastrostomy (PEG) has become an important modality to provide enteral access for long-term nutritional support. Nevertheless, aspiration of liquid nutrients due to vomiting and reflux esophagitis caused by gastroesophageal reflux (GER) is a significant problem associated with tube feeding by PEG. MATERIALS AND METHODS First, gastrostomy as an access for enteral nutrition and esophagostomy for gastroesophageal pH and Bilitec monitoring were performed in eight beagle dogs, in which the influence of viscosity of an enteral formula on the degree of GER was investigated using a commercially available liquid meal and a nearly isocaloric half-solid diet that was prepared by adding a solution mixed with dextrin, pectin, and calcium lactate. Second, similar studies were accomplished in seven beagle dogs that underwent cardioplasty and intrathoracic cardiopexy (a model of GER disease [GERD]). RESULTS There was no difference in the degree of GER evaluated by Bilitec monitoring between liquid and half-solid nutrients in eight normal dogs, whereas solidifying nutrients significantly reduced the frequency of reflux during the feeding periods (P=0.0180) and post-feeding periods (P=0.0277) in a model of GERD. CONCLUSION The use of half-solid nutrients for enteral feeding reduced the frequency of reflux in a dog model of GERD.

Complete response of esophageal small cell carcinoma amrubicin treatment

Small cell carcinoma of the esophagus (SmCCE) is a rare and aggressive disease known to have a poor prognosis. SmCCE patients are generally treated with a chemotherapeutic regimen for small cell lung cancer. Salvage therapy for patients with relapsed or refractory tumors has not yet been established. A 63-year-old man with extensive SmCCE was treated with chemotherapy consisting of cisplatin (CDDP) and irinotecan (CPT-11). After the second course of CPT-11/CDDP, the celiac lymph node increased in size. Amrubicin (AMR) as second-line chemotherapy was started. The patient had a complete response after the fifth course of AMR, resulting in an 8-month progression-free survival after initial administration. This case suggests that, as in small cell lung cancer, AMR is effective for SmCCE.

Video-Assisted Thoracoscopic Surgery for Localized Neurofibroma of the Esophagus: Case Report and Review of the Literature

Esophageal submucosal tumors are less common than other gastrointestinal tract tumors. Leiomyoma is the most common benign esophageal SMT, accounting for more than 70% of these tumors. We report on a case of a 56-year-old woman with a 3-cm diameter midthoracic esophageal submucosal tumor. Magnetic resonance imaging suggested leiomyoma or neurofibroma. Video-assisted thoracoscopic surgery was performed to enucleate the tumor from the esophageal wall by splitting the muscle layers. The postoperative course was uneventful, and the patient was discharged on postoperative day 8. Immunohistochemical staining confirmed the diagnosis of esophageal neurofibroma. Gastrointestinal tract involvement of neurofibromatous lesions is rare and occurs most frequently as a systemic manifestation of von Recklinghausen disease. Cases of localized esophageal neurofibroma with prior or subsequent evidence of generalized neurofibromatosis have rarely been documented. This is a rare case of isolated esophageal neurofibroma without classic systemic manifestations of generalized neurofibromatosis, and it is the first reported case treated by video-assisted thoracoscopic surgery.

Direct percutaneous endoscopic duodenostomy: a case report.

A 78-year-old male, who had undergone left upper lobectomy because of traumatic pulmonary contusion at the age of 25 years, succumbed to left hemiplegia with impaired consciousness that was caused by right putaminal hemorrhage. Aspiration pneumonia was complicated and he was set on tracheostomy and tube feeding through a nasogastric tube. Although it was apparent that enteral nutrition through the percutaneous endoscopic gastrostomy was appropriate for him, performing a percutaneous endoscopic gastrostomy seemed impossible as the computed tomography revealed that the elevated stomach was located behind the heart. In this patient, we successfully performed a direct percutaneous endoscopic duodenostomy without any complication.