Reovirus oncolysis: the Ras/RalGEF/p38 pathway dictates host cell permissiveness to reovirus infection

Reovirus is a benign human virus that was recently found to have oncolytic properties and is currently in clinical trials as a potential cancer therapy. We have previously demonstrated that activation of Ras signaling, a common event in cancer, renders cells susceptible to reovirus oncolysis. In this study, we investigate which elements downstream of Ras are important in reovirus infection. By using a panel of NIH 3T3 cells transformed with activated Ras mutated in the effector-binding domain, we found that only the RasV12G37 mutant, which was unable to signal to Raf or phosphatidylinositol 3-kinase but retained signaling capability to guanine nucleotide-exchange factors (GEFs) for the small G protein, Ral (known as RalGEFs), was permissive to reovirus. Expression of the activated mutant of the RalGEF, Rlf, also allowed reovirus replication. Specific inhibition of the Ral pathway by using dominant-negative RalA rendered normally permissive H-Ras cells (cells expressing activated Ras) resistant to reovirus. To further identify elements downstream of RalGEF that promote reovirus infection, we used chemical inhibitors of the downstream signaling elements p38 and JNK. We found that reovirus infection was blocked in the presence of the p38 inhibitor but not the JNK inhibitor. Together, these results implicate a Ras/RalGEF/p38 pathway in the regulation of reovirus replication and oncolysis.     

Extrinsic tongue and suprahyoid muscle activities during mastication in freely feeding rabbits

To evaluate the coordination of tongue and suprahyoid muscle activities during natural mastication, electromyograms (EMGs) of jaw-closer, jaw-opener, suprahyoid (mylohyoid, MH), tongue-retractor (styloglossus, SG) and tongue-protractor (genioglossus, GG) muscles were recorded as well as the jaw-movement trajectories in vertical and horizontal axes in awake rabbits. Each masticatory cycle had three components including the fast-closing (FC), slow-closing (SC) and opening (Op) phases. The duration of the SC phase was much longer during pellet chewing while the durations of the FC and Op phases were much shorter during pellet chewing than bread or banana chewing. The jaw movements during banana chewing had a small amplitude of lateral excursion and a large amplitude of gape as compared with those during pellet and bread chewing. The MH muscle exhibited double-peaked EMG bursts during the Op phase. The MH bursts in the late part of the Op phase were dominant on the non-chewing side during pellet and bread chewing. The SG muscle also exhibited double-peaked EMG bursts. During pellet and bread chewing, the SG bursts during the SC phase were significantly larger on the chewing side than the non-chewing side. These bursts were also dominant during pellet chewing as compared with banana chewing. There was little difference in the GG bursts between the chewing and non-chewing sides or among the foods. Our results suggest that patterns of the MH and SG muscle activity are affected by the peripheral inputs and/or chewing patterns while those of the GG muscle activity was less modulated regardless of the consistency of foods.     

White matter loss in the splenium of the corpus callosum in a case of posterior cortical atrophy: a diffusion tensor imaging study

There have been several functional imaging studies using PET and SPECT to investigate posterior cortical atrophy (PCA). These studies have suggested dysfunction of corticocortical connections which is consistent with the occipitoparietal stream. However, there are no reports suggesting disturbance of the white matter that interconnects the temporal, parietal and occipital cortices. We measured fractional anisotropy (FA) in the genu and splenium of the corpus callosum and created color maps using diffusion tensor imaging (DTI), which is a relatively new MRI technique that allows visualization of the directionality of water diffusion, in a patient with PCA and compared these findings with those in 5 typical Alzheimer disease (AD) patients. The PCA patient was a 75-year-old man presenting with progressive complex visual disorder who satisfied the clinical diagnostic criteria for PCA. In 5 typical AD patients, the FA index in the splenium was higher than that in the genu; however, in the PCA patient, the FA index in the splenium was significantly lower than that in the genu. A DTI-based color map of the PCA patient showed reduction of anisotropy and fiber volume in the splenium. These findings suggest that the splenium of the corpus callosum secondarily degenerated due to neuronal degeneration of the temporal, parietal and occipital cortices and suggest that reduction of the FA in the splenium is one of the characteristics of PCA.     

Neuropathological features of a case with schizophrenia and prion protein gene P102L mutation before onset of Gerstmann-Sträussler-Scheinker disease

Gerstmann-Sträussler-Scheinker disease (GSS) is a hereditary transmissible spongiform encephalopathy associated with prion protein gene mutation P102L. The age of onset is roughly restricted to around the sixth decade; however, it is unclear whether the disease-specific pathology of GSS is already evident in the pre-clinical stage. We had a chance to examine an autopsy case with PRNP P102L mutation. The patient had died at 50 years of age before the clinical symptoms of GSS had appeared; neither neuronal loss, gliosis nor spongiform change was found anywhere in the brain. Immunohistochemistry failed to detect any deposition of prion protein. It is thus considered that amyloid plaque formation in GSS probably develops in a relatively rapid fashion compared with Alzheimer's disease. Although the patient suffered from schizophrenia, no significant pathological changes were detected except for astrocytic inclusion bodies in the cerebral cortex. The nature and significance of the inclusion bodies, which are not observed in patients with GSS, remain unclear.     

Effect of cortical masticatory area stimulation on swallowing in anesthetized rabbits

The effects of stimulation of the cortical masticatory area (CMA) on swallowing evoked by superior laryngeal nerve (SLN) were studied in anesthetized rabbits. Electromyographic activity of the thyrohyoid, masseter, and digastric muscles and jaw-movement trajectories were recorded to monitor rhythmic jaw movements (RJMs) or swallowing. A systematic series of microelectrode penetrations within the CMA was made for each animal, and the effects of CMA stimulation on swallowing were tested by comparing the number of swallows evoked by stimulation of the CMA alone, the SLN alone, and simultaneous stimulation of the SLN and CMA. A significant facilitatory effect was observed in 49 (52%) of the 95 CMA loci tested. No significant effect was noted in the remaining 46 loci. Three different types of RJMs were evoked by CMA stimulation, and topographical organization was noted among CMA loci that evoked different types of RJMs. A high percentage of (77%) the CMA loci that evoked RJMs with a prominent horizontal excursion of the jaw facilitated swallowing and was located in the posterolateral and deep part of the CMA. A majority (88%) of the CMA loci that evoked RJMs with small circular jaw movements did not affect swallowing and was located in the anteromedial and shallow part of the CMA. The facilitatory effect of CMA stimulation on swallowing remained even after removal of peripheral sensory inputs by means of deafferentation of infraorbital and inferior alveolar nerves. Results suggest the existence of facilitatory descending pathways to the swallowing center from particular intracortical loci of CMA.     

Transaqueductal aspiration of pontine hemorrhage with the aid of a neuroendoscope. Technical note

The authors advocate the use of a 1.7-mm fiberscope to evaluate a hypertensive bilateral tegmental pontine hemorrhage that has ruptured, in part, into the fourth ventricle. In applying this new technique, a fiberscope, which contains a guide tube in the working channel, is inserted into the aqueduct. After the endoscope has been removed, a silicone tube is slid along the guide tube. The hematoma is evacuated through the silicone tube and a potassium titanyl phosphate laser is used to achieve hemostasis.     

Inhibition of the norepinephrine transporter function in cultured bovine adrenal medullary cells by bisphenol A

We report here the effects of an environmental estrogen, bisphenol A, on norepinephrine (NE) transporter function in cultured bovine adrenal medullary cells. The effects of bisphenol A were compared to those of 17beta-estradiol. Bisphenol A significantly inhibited [3H]NE uptake by the cells in a concentration-dependent manner (1-100 microM). Kinetic analysis revealed that bisphenol A, as well as 17beta-estradiol, noncompetitively inhibited [3H]NE uptake. Bisphenol A and 17beta-estradiol inhibited the specific binding of [3H]desipramine to plasma membranes isolated from bovine adrenal medulla. As shown by Scatchard analysis of [3H]desipramine binding, bisphenol A increased the dissociation constant (K(d)) and decreased the maximal binding (B(max)), indicating a mixed type of inhibition. 17beta-Estradiol increased the K(d) without altering the B(max), thereby indicating competitive inhibition. The present findings suggest that bisphenol A inhibits the function of the NE transporter by acting on a site different from that of 17beta-estradiol in the adrenal medulla and probably in the brain noradrenergic neurons.     

Cavernous sinus dural arteriovenous fistula complicated by pontine venous congestion. A case report

BACKGROUND: Brainstem venous congestion is a rare but serious complication of the CS-dAVF (cavernous sinus dural arteriovenous fistual). CASE DESCRIPTION: A 71-year-old woman presented with right abducens nerve palsy. Brain MRI showed a solitary lesion in the right upper pons. Cerebral angiogram revealed the right CS-dAVF with retrograde venous drainage into the cerebellar cortical veins and the anterior pontomesencephalic vein. The patient was treated with stereotactic radiosurgery, resulting in complete resolution of the pontine lesion and the neurologic symptom. CONCLUSION: A solitary brainstem lesion can be caused by CS-dAVF as a rare complication. Careful diagnosis and treatment are important to avoid permanent neurologic deficits.     

Dynamic computed tomography myelography for the investigation of cervical degenerative disease

Dynamic computed tomography (CT) myelography was conducted in 15 patients with cervical degenerative disease to assess the lesions responsible for their symptoms. CT myelography was performed using a multi-detector row helical CT system in dynamic positions (flexion or extension or both) in addition to the neutral position. Fine sagittal reconstructed images could be obtained in addition to axial images. This method provided static information including cervical vertebral body deformities, and good contrast images of the spinal cord, nerve roots, and cerebrospinal fluid space. In addition, laterality of the offending lesion and changes exaggerated by cervical motion were clearly shown in both axial and sagittal images. Ten of 15 patients demonstrated dynamic changes including dynamic canal stenosis or spinal cord impingement. The operative strategies were changed based on dynamic CT myelography findings in three of the 15 patients. Dynamic CT myelography can provide the axial and sagittal images required for flexion-extension studies, and in combination with conventional imaging modalities, provides valuable information for determining treatment strategies and objectives.