Comparison of expression and proliferative effect of pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors on human astrocytoma cell lines.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide considered to be a potent regulator of astrocytes. It has been reported that PACAP also affects astrocytoma cell properties, but the proliferative effects of this peptide in previous reports were inconsistent. The purpose of this study was to search for correlations between malignant potential, PACAP/PACAP receptor expression, and the proliferative potential of four astrocytoma cell lines (KNS-81, KINGS-1, SF-126, and YH-13). Immunohistochemical observations were performed using astrocyte lineage markers with a view to establishing malignant potential, which is inversely correlated to differentiation status in astrocytoma cells. YH-13 showed the most undifferentiated astrocyte-like status, and was immunopositive to a cancer stem cell marker, CD44. These observations suggest that YH-13 is the most malignant of the astrocytoma cell lines tested. Moreover, the strongest PAC1-R immunoreactivity was observed in YH-13 cells. Using real-time PCR analysis, no significant differences among cell lines were detected with respect to PACAP mRNA, but PAC1-R and VPAC1-R mRNA levels were significantly increased in YH-13 cells compared with the other cell lines. Furthermore, when cell lines were treated with PACAP (10(-11) M) for 3 days, the YH-13 cell line, but not of the other cell lines, exhibited a significantly increased cell number. These results suggest that PACAP receptor expression is correlated with the malignant and proliferative potential of astrocytoma cell lines.

PACAP stimulates functional recovery after spinal cord injury through axonal regeneration.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuroprotective peptide expressed in the central nervous system. Although many studies have shown a neuroprotective effect of PACAP, the mechanism of PACAP in the treatment of spinal cord injury (SCI) is yet to be elucidated. The purpose of this study was to examine the efficacy and underlying mechanism of PACAP in a mouse SCI model where PACAP was delivered via a biodegradable hydrogel. When PACAP or saline was delivered immediately after SCI, the functional motor recovery 14 days after SCI was significantly improved in the PACAP group compared with that in the saline group. Expression levels of messenger RNA (mRNA) for collapsin response mediator protein 2 (CRMP2), a factor related to axonal regeneration, were increased in the PACAP group 14 days after SCI compared with those in the saline group. A significantly increased number of CRMP2-positive cells were observed around the injury lesion in the PACAP group, while CRMP2 co-labeling with neuronal and oligodendrocyte markers was detected in intact spinal cord. Fourteen days after SCI, anterograde tracing revealed that a significantly increased number of neuronal fibers extended caudally from the lesion epicenter in the PACAP group. These results suggest that PACAP stimulates functional motor recovery after SCI through axonal regeneration mediated by CRMP2.

Acetylcholine promotes the emergence and elongation of lateral roots of Raphanus sativus.

Radish (Raphanus sativus L.) was grown on four layers of paper towel moistened with distilled water with and without acetylcholine (ACh) for five days in the dark after sowing. ACh at 1 nM promoted the growth (emergence and elongation) of lateral roots of radish plants, but had no effect on the stems and main roots. Moreover, ACh enhanced the dry weight of roots [main (primary) + lateral roots]. Neostigmine, an inhibitor of acetylcholinesterase (AChE) also promoted the emergence and elongation of lateral roots, and atropine, a competitive inhibitor of ACh receptor, suppressed the emergence and elongation. ACh suppressed the activity of AChE and increased the amount of proteins and pyridine nucleotides (NAD and NADH) in the roots of the seedlings. It also increased the activities of NAD-forming enzymes [NAD synthetase and ATP-nicotinamide mononucleotide (ATP-NMN) adenyltransferase], and enhanced the amount of DNA in the roots of the seedlings. The relationship between ACh and the emergence and growth of lateral roots was discussed from a biochemical viewpoint.

Mucinous cystadenocarcinoma of the urachus associated with pseudomyxoma peritonei with emphasis on MR findings.

Urachal mucinous cystadenocarcinoma associated with pseudomyxoma peritonei is extremely rare; only 11 cases are reported. We describe the characteristic imaging findings of this disorder and correlate imaging features by computed tomography, magnetic resonance imaging, and ultrasonography with operative findings and histopathologic specimens.

Inflammatory myofibroblastic tumor in the mediastinum mimicking a malignant tumor.

Inflammatory myofibroblastic tumor (IMT), also called "inflammatory pseudotumor", is a rare benign tumor composed of spindle cells with a variable infiltrate of inflammatory cells and fibrous tissue. There have been many reported cases of IMT in every organ system; however, IMT in the mediastinum is rare. We report a rare, proven case of spontaneous regression of IMT in the right cardiophrenic angle. The diagnosis was confirmed by histopathology, and the observation of serial ultrasonographic and computed tomography images over the course of three months revealed a picture consistent with spontaneous regression of the inflammatory pseudotumor.

Explicit contextual information selectively contributes to predictive switching of internal models.

Many evidences suggest that the central nervous system (CNS) acquires and switches internal models for adaptive control in various environments. However, little is known about the neural mechanisms responsible for the switching. A recent computational model for simultaneous learning and switching of internal models proposes two separate switching mechanisms: a predictive mechanism purely based on contextual information and a postdictive mechanism based on the difference between actual and predicted sensorimotor feedbacks. This model can switch internal models solely based on contextual information in a predictive fashion immediately after alteration of the environment. Here we show that when subjects simultaneously adapted to alternating blocks of opposing visuomotor rotations, explicit contextual information about the rotations improved the initial performance at block alternations and asymptotic levels of performance within each block but not readaptation speeds. Our simulations using separate switching mechanisms duplicated these effects of contextual information on subject performance and suggest that improvement of initial performance was caused by improved accuracy of the predictive switch while adaptation speed corresponds to a switch dependent on sensorimotor feedback. Simulations also suggested that a slow change in output signals from the switching mechanisms causes contamination of motor commands from an internal model used in the previous context (anterograde interference) and partial destruction of internal models (retrograde interference). Explicit contextual information prevents destruction and assists memory retention by improving the changes in output signals. Thus, the asymptotic levels of performance improved.

[A case of gastrointestinal stromal tumor of the stomach arising from the muscularis mucosae].

A 75-year-old man, in whom upper gastrointestinal endoscopy revealed a submucosal tumor in the greater curvature of the gastric angle, was hospitalized for further investigations. Since the tumor was shown to be located in the submucosal layer by endoscopic ultrasonography, we performed endoscopic mucosal resection. Pathological studies of the resected specimen revealed a gastrointestinal stromal tumor of the stomach. It was also formed that the tumor was connected not to muscularis propria, but to the muscularis mucosae. There has been no previous report about a case of gastrointestinal stromal tumor of the stomach arising from the muscularis mucosae in Japan.

Rupture of rectal varices treated with endoscopic variceal ligation.

We report here 3 cases of rectal varices treated with endoscopic variceal ligation and discuss the pathogenesis, treatment, and prognosis of rectal varices with referring to previous reports. Of the 3 patients, 2 had been diagnosed as liver cirrhosis and 1 as extrahepatic portal hypertension. All of the 3 patients had previously undergone treatment of esophagogastric varices. The rupture of rectal varices appeared to have some relationship with the treatment of esophageal varices. In previous reports, 73% of patients with ruptured rectal varices treated with endoscopic injection sclerotherapy or endoscopic variceal ligation had undergone treatments of esophageal varices. The endoscopic treatments resulted in a favorable prognosis in 2 patients. Although no fatality from endoscopic injection sclerotherapy or endoscopic variceal ligation has been reported, 1 of the present 3 cases died of liver failure.