Reorganization of brain activity for multiple internal models after short but intensive training

Internal models are neural mechanisms that can mimic the input-output properties of controlled objects. Our studies have shown that: 1) an internal model for a novel tool is acquired in the cerebellum (Imamizu et al., 2000); 2) internal models are modularly organized in the cerebellum (Imamizu et al., 2003); 3) their outputs are sent to the premotor regions after learning (Tamada et al., 1999); and 4) the prefrontal and parietal regions contribute to the blending of the outputs (Imamizu et al., 2004). Here, we investigated changes in global neural networks resulting from the acquisition of a new internal model. Human subjects manipulated three types of rotating joystick whose cursor appeared at a position rotated 60 degrees, 110 degrees, or 160 degrees around the screen's center. In a pre-test after long-term training (5 days) for the 60 degrees and 160 degrees joysticks, brain activation was scanned during manipulation of the three joysticks. The subjects were then trained for the 110 degrees for only 25 min. In a post-test, activation was scanned using the same method as the pre-test. Comparisons of the post-test to the pre-test revealed that the volume of activation decreased in most of the regions where activation for the three rotations was observed. However, there was an increase in volume at a marginally significant level (p < .08) only in the inferior-lateral cerebellum and only for the 110 degrees joystick. In the cerebral cortex, activation related to 110 degrees decreased in the prefrontal and parietal regions but increased in the premotor and supplementary motor area (SMA) regions. These results can be explained by a model in which outputs of the 60 degrees and 160 degrees internal models are blended by prefrontal and parietal regions to cope with the novel 110 degrees joystick before the 25-minute training; after the acquisition within the cerebellum of an internal model for the 110 degrees, output is directly sent to the premotor and SMA regions, and activation in these regions increases.     

The Influence of Brain Death on Tissue Factor Expression in the Pancreatic Tissues and Isolated Islets in Rats

Introduction

Tissue factor (TF) in islets has been identified as the main trigger of the instant blood-mediated inflammatory reaction. Because the crucial events that directly induce TF remain to be determined, we focused on the influence of brain death (BD) on TF expression in pancreatic tissues and isolated islets.

Materials and Methods

BD was induced in male Lewis rats weighing 250-300 g by inflation of a Fogarty catheter placed intracranially. The rats were mechanically ventilated for 6 hours until removal of the pancreas. The expression of TF protein in pancreatic tissues was examined using Western blotting assay. Messenger RNA (mRNA) expressions of TF in pancreatic tissue and isolated islets were analyzed using real-time polymerase chain reaction (PCR) assay. The influence of BD on the isolation outcome was evaluated by islet yield, purity, viability, and function.

Results

TF protein and mRNA levels in the pancreatic tissues were similar between the groups. However, TF mRNA in the isolated islets of the BD group was significantly greater than that of the control group (P = .04). Islet yield was considerably lower, and purity significantly lower in the BD than the control group (P = .002). Unexpectedly, ATP/DNA ratio and respiratory activity were comparable between the groups.

Conclusions

Although BD per se was not sufficient to induce TF expression in pancreatic tissues, BD combined with subsequent warm ischemic damage during isolation procedures remarkably up-regulated TF expression in isolated islets, suggesting that BD is of great importance as an initiator of TF induction in the islet grafts. The present study demonstrated that the expression of inflammatory mediators rather than islet viability is more susceptible to BD.     

Efficacy of an artificial pancreas device for achieving tight perioperative glycemic control in living donor liver transplantation

Intraoperative hyperglycemia during liver transplantation can induce infectious bacterial complications after surgery. The aim of this study was to evaluate the efficacy of the artificial endocrine pancreas in achieving perioperative blood glucose control and preventing infection in patients undergoing living donor liver transplantation (LDLT). We compared 14 patients with an artificial endocrine pancreas device to 14 patients who underwent glycemic control using the sliding scale method with respect to perioperative blood glucose level and postoperative infection. In this study, we aimed to control the perioperative glucose levels consecutively for 24 hours from the induction of anesthesia. The average blood glucose level in the artificial pancreas group was significantly lower than that in the sliding scale group (118 vs. 141 mg/dL, P < 0.05). The postoperative bacterial infection rate of the artificial pancreas group was significantly lower than that of the sliding scale group within one month after LDLT (35.7% vs. 78.6%, P < 0.05). Multiple regression analysis showed non‐application of artificial endocrine pancreas as a significant risk factor of posttransplant infection. The artificial endocrine pancreas enabled the perioperative glucose level to be stably controlled without hypoglycemia. Artificial pancreas may reduce the incidence of postoperative infection after LDLT.     

Rehospitalization after pediatric living-donor liver transplantation

BACKGROUND: Although rehospitalization is one of the factors affecting quality of life after successful liver transplantation, the effects of rehospitalization have not been assessed to date. PATIENTS AND METHODS: Of 40 consecutive cases of pediatric living-donor liver transplantation (LDLT) performed between April 1994 and October 2000, 28 patients with a graft survival of more than 1 year were enrolled in this study to examine rehospitalization after successful LDLT. The rate and cause of rehospitalization were analyzed retrospectively on the basis of medical records. RESULTS: A total of 23 of the 28 patients were rehospitalized. There were 84 episodes of rehospitalization. The mean number of rehospitalization days per episode per patient was 21.06 +/- 21.02 days. The rate of total rehospitalization days to the days after the hospitalization for LDLT was 6.56% +/- 8.73%. Rehospitalization episodes were attributable to the following: cholangitis (21.4%), viral infection (16.7%), and portal stenosis (PS) (13.1%). Rehospitalization as the result of rejection accounted for 9.5% of the episodes. The period of rehospitalization was long in the case of cholangitis (49.7 +/- 62.4 days), PS (13.8 +/- 13.4 days), and rejection (52.9 +/- 45.4 days). Although there were a lot of rehospitalization episodes as the result of viral infection subsequent to cholangitis, each rehospitalization period lasted 4.4 +/- 6.6 days. CONCLUSION: It is suggested that prevention of cholangitis and PS, which were the causes of frequent and long rehospitalization periods, would result in a reduction of rehospitalization and therefore a better quality of life after pediatric LDLT.     

Intestinal obstruction caused by colonic metastasis from intrahepatic cholangiocarcinoma 6?years after removal of the primary tumor: report of a case

We report a case of intestinal obstruction caused by metastasis that manifested 6 years after surgery for intrahepatic cholangiocarcinoma (ICC). The patient, a 57-year-old man, had undergone resection of the hepatic left lobe, Spiegel lobe, and extrahepatic bile duct, following which histopathological examination had confirmed the diagnosis of ICC and that the resection margins were free from disease. There had been no signs of recurrence until an increase in the CA19-9 level was detected 6 years later. Colonoscopy revealed an ulcer-like lesion and stenosis at the level of the hepatic flexure. The patient was subsequently admitted to our hospital with abdominal pain and underwent right hemicolectomy with partial resection of hepatic segment V. Based on the immunohistological finding that the expression pattern of cytokeratins and mucins was consistent with ICC origin rather than colon cancer origin, we diagnosed colon metastasis from ICC.     

Three cases of pulmonary hamartoma appearing after radical nephrectomy for renal cell carcinoma

We report 3 patients with pulmonary hamartoma, all of whom had undergone nephrectomy for renal cell carcinoma. A lung tumor was detected 2 to 9-months following nephrectomy. Preoperative diagnosis was pulmonary metastasis from renal cell carcinoma and pulmonary tumor resection was performed in each case. There was a 9- to 12-month interval between the detection and resection of the lung tumor. The histological diagnosis of the lung tumor in all three patient was pulmonary hamartoma. Following the resection of the lung tumor, recurrence was not noted in any of the patients.