Establishment of Dental Epithelial Cell Line (HAT-7) and the Cell Differentiation Dependent on Notch Signaling Pathway

Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway.     

Preoperative oral rehydration therapy with 2.5 % carbohydrate beverage alleviates insulin action in volunteers

Preoperative carbohydrate loading enhances insulin action by approximately 50 %. In some Japanese hospitals, preoperative oral rehydration therapy is performed for preventing dehydration during surgery. We hypothesized that preoperative oral rehydration therapy with a 2.5 % carbohydrate beverage that is widely used in Japan can enhance insulin action. Therefore, we investigated the effect of this 2.5 % carbohydrate beverage on insulin action in volunteers. Six healthy volunteers participated in this crossover randomized study. The participants were segregated into 2 groups: an oral rehydration therapy with 2.5 % carbohydrate beverage group (group A) and a control group (group B). Subjects in group B were allowed to drink only water from 9 pm the day before the test; conversely, group A fasted from 9 pm onward and drank 500 ml of the beverage containing 2.5 % carbohydrate (OS-1; Otsuka Pharmaceutical Factory, Tokushima, Japan) between 9 and 12 pm and again at 6.30 am. At 8.30 am, a hyperinsulinemic normoglycemic clamp was initiated using an artificial pancreas STG-22 (Nikkiso, Tokyo, Japan). Insulin action was evaluated in both groups using the glucose infusion rate. Blood glucose levels at the initiation of the clamp procedure were similar. However, the glucose infusion rate for group A was significantly higher than that of group B (8.6 ± 1.5 vs. 6.8 ± 2.0 mg/kg/min, p = 0.009). In conclusion, the hyperinsulinemic normoglycemic clamp using an artificial pancreas showed that the administration of a 2.5 % carbohydrate oral rehydration solution for preoperative oral rehydration therapy improves insulin action in volunteers.     

Efficacy of Transversus Abdominis Plane Block and Rectus Sheath Block in Laparoscopic Inguinal Hernia Surgery

We aimed to assess the efficacy of transversus abdominis plane (TAP) block and rectus sheath (RS) block in patients undergoing laparoscopic inguinal hernia surgery. Few studies have addressed the efficacy and safety associated with TAP block and RS block for laparoscopic surgery. Thirty-two patients underwent laparoscopic inguinal hernia surgery, either with TAP and RS block (Block⁺ group, n = 18) or without peripheral nerve block (Block⁻ group, n = 14). Preoperatively, TAP and RS block were performed through ultrasound guidance. We evaluated postoperative pain control and patient outcomes. The mean postoperative hospital stays were 1.56 days (Block+ group) and 2.07 days (Block⁻ group; range, 1–3 days in both groups; P = 0.0038). A total of 11 patients and 1 patient underwent day surgery in the Block⁺ and Block⁻ groups, respectively (P = 0.0012). Good postoperative pain control was more commonly observed in the Block⁺ group than in the Block⁻ group (P = 0.011). TAP and RS block was effective in reducing postoperative pain and was associated with a fast recovery in patients undergoing laparoscopic inguinal hernia surgery.Key words: TAP block, RS block, Inguinal hernia, Laparoscopic surgeryInguinal hernia repair is one of the most frequently performed surgical operations. The debate regarding the best repair technique for inguinal hernia is ongoing. Several trials have compared the efficacy of the Lichtenstein and laparoscopic approach for inguinal hernia repair.^1–6 Laparoscopic repair of inguinal hernia has certain advantages over open repair, such as reduced postoperative pain and morbidity, early recovery, rapid return to work, and better quality of life.^3–7 Several strategies have been reported to ameliorate postoperative pain in laparoscopic surgery.⁸The transversus abdominis plane (TAP) block is a regional anesthetic technique that provides analgesia to the parietal peritoneum as well as to the skin and muscles of the anterior abdominal wall.^9,10 Despite a relatively low risk of complications and a high success rate using modern techniques, TAP block remains overwhelmingly underused. Although the technique is technically straightforward, it has not been adopted in clinical practice.^9,11 Moreover, rectus sheath (RS) block has been reported to be effective for pain management in patients undergoing umbilical hernia repair surgery.¹²Generally, in laparoscopic inguinal hernia surgery, the sites of port incision are on the umbilical and bilateral middle abdomen. Those sites are associated with considerable postoperative discomfort. Thus, we performed TAP and RS block to ameliorate postoperative pain and improve patient outcomes. Here, we aimed to assess the efficacy of TAP and RS block in patients undergoing laparoscopic inguinal hernia surgery.     

Downregulation of GSTM2 enhances gemcitabine chemosensitivity of pancreatic cancer in vitro and in vivo

Glutathione-S-transferases (GSTs) not only show cytoprotective role and their involvement in the development of anticancer drug resistance, but also transmit signals that control cell proliferation and apoptosis. However, the role of GST isoforms in chemotherapy resistance remains elusive in pancreatic cancer. Here, we demonstrated that gemcitabine treatment increased the GSTM2 expression in pancreatic cancer cell lines. Knockdown of GSTM2 by siRNA elevated apoptosis and decreased viability of pancreatic cancer cells treated with gemcitabine. Moreover, in vivo experiments further showed that shRNA induced GSTM2 downregulation enhanced drug sensitivity of gemcitabine in orthotopic pancreatic tumor mice. We also found that GSTM2 levels were lower in tumor tissues than in non-tumor tissues and higher GSTM2 expression was significantly associated with longer overall survival. In conclusion, our findings indicate that GSTM2 expression is essential for the survival of pancreatic cancer cells undergoing gemcitabine treatment and leads to chemo resistance. Downregulation of GSTM2 in pancreatic cancer may benefit gemcitabine treatment. GSTM2 expression in patients also shows significant correlation with overall survival. Thus, our study suggests that GSTM2 is a potential target for chemotherapy optimization and prognostic biomarker of pancreatic cancer.     

A case of pulmonary sarcoidosis with usual interstitial pneumonia-like lesions distributed predominantly in the lower lung fields]

In 2000, in a 75-year-old man, nodular and reticular opacities were detected in both lower lung fields. He was admitted to our hospital for further examination of these abnormal shadows. Bronchoscopic examination revealed pulmonary sarcoidosis. Prednisolone was prescribed because cardiac sarcoidosis was diagnosed as a clinical complication. In April 2002, the patient visited our hospital for dyspnea on effort. Chest radiography and computed tomography showed nodular and reticular opacities in the right upper lobe, and video-assisted thoracoscopic surgery was performed on the basis of a histological diagnosis. The histological findings of the biopsied specimens revealed a lesion of the type seen in usual interstitial pneumonia, whereas non-caseous granulomas were not detected. His symptoms and chest radiographic findings improved and stabilized with prednisolone and azathioprine. In the present case of pulmonary sarcoidosis, the reticular and nodular opacities predominantly distributed in both lower lung fields, and the histological findings obtained by video-assisted thoracoscopic surgery showed a usual interstitial pneumonia-like lesion. These findings may assist in the understanding of the process of development of pulmonary sarcoidosis.