Cerebral hemodynamics on MR perfusion images before and after bypass surgery in patients with giant intracranial aneurysms

Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm.BACKGROUND AND PURPOSE: Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm

Development of a site conditions map for the Campania-Lucania region (southern Apennines, Italy)

Having a reliable site conditions estimate is an important step to analyze and predict earthquake ground motions. To provide this information for the Campania-Lucania region (southern Apennines, Italy), in the framework of a collaboration with regional civil protection agency, geologic units shown on 1:250,000 scale geologic map, have been sorted together into four categories based on age and geological similarities. According to the site classification defined in engineering building codes, we have assigned to each site classes, a value or range of values of the average shear-wave velocity to 30 m (Vs30) and of the site dominant period. Thus, we have digitized the category boundaries from the map tracing only the geologic contacts that separate units of different site classes. The accuracy of the site-conditions map is only limited by the number of Vs profiles, used to compute the Vs30, and geologic data available so far. Analyses with new data will allow updates and modifications of this map. Anyhow, the resulting site classification map may be an helpful tool to better characterizing the sites effects for those applications where amplification values at large scale are need, such as ground-shaking maps or seismic hazard maps

New tools for scientific learning in the EduSeis project: the e-learning experiment

The Educational Seismological Project (EduSeis) is a scientific and educational project, the main aim of which is the development and implementation of new teaching methodologies in Earth Sciences, using seismology as a vehicle for scientific learning and awareness of earthquake risk. Within this framework, we have recently been experimenting with new learning and information approaches that are mainly aimed at a high school audience. In particular, we have designed, implemented and tested a model of an e-learning environment in a high school located in the surroundings of the Mt. Vesuvius volcano. The proposed e-learning model is built on the EduSeis concepts and educational materials (web-oriented), and is based on computer-supported collaborative learning. Ten teachers from different disciplines and fifty students at the ITIS «Majorana» technical high school (Naples) have been taking part in a cooperative e-learning experiment in which the students have been working in small groups (communities). The learning process is assisted and supervised by the teachers. The evaluation of the results from this cooperative e-learning experiment has provided useful insights into the content and didactic value of the EduSeis modules and activities. The use of network utilities and the «Learning Community» approach promoted the exchange of ideas and expertises between students and teachers and allowed a new approach to the seismology teaching through a multidisciplinary study

An advanced seismic network in the Southern Apennines (Italy) for seismicity investigations and experimentation with earthquake early warning.

The last strong earthquake that occurred in the southern Apennines, the Irpinia earthquake on 23 November 1980 (M 6.9), was characterized by a complex rupture mechanism that ruptured three different faults (Bernard and Zollo 1989). This earthquake was well studied, and the quantity of data available has allowed a very detailed definition of the geometry and mechanisms of faults activated during this seismic event (Westaway and Jackson 1987; Pantosti and Valensise 1990). Even more than 20 years after the main event, the seismotectonic environment that contains the fault system on which the 1980 earthquake occurred shows continued background seismic activity including moderate-sized events such as the 1996 (M 5.1), 1991 (M 5.1) and 1990 (M 5.4) events. Moreover, the locations of the microearthquakes (taken from the database of the Istituto Nazionale di Geofisica e Vulcanologia, INGV) define an epicentral area with a geometry and extent surprisingly similar to that of the 1980 earthquake and its aftershocks (figure 1A). These simple observations suggest that it may be possible to study the preparation cycles of strong earthquakes on active faults by studying the microseismicity between seismic events. With this in mind, a seismic network of large dynamic range was planned and is now in an advanced phase of completion in the southern Apennines. Called ISNet (Irpinia Seismic Network), it is equipped with sensors that can record high-quality seismic signals from both small-magnitude and strong earthquakes, from which it will be possible to retrieve information about the rupture process and try to understand the scaling relationships between small and large events. Due to its high density, wide dynamic range, and advanced data-acquisition and data-transmission technologies, the network is being upgraded to become the core infrastructure of a prototype system for seismic early warning and rapid post-event ground-shaking evaluation in the Campania region, which has seismic hazard that ranks among the highest in Italy (Cinti et al. 2004). ISNet will be devoted to real-time estimation of earthquake location and magnitude and to measuring peak ground-motion parameters so as to provide rapid ground-shaking maps for the whole of the Campania region. The information provided by ISNet during the first seconds of a potentially damaging seismic event can be used to activate several types of security measures, such as the shutdown of critical systems and lifelines (Iervolino et al. 2006). The implementation of a modern seismic network involves many different research and technological aspects related to the development of sophisticated data management and processing. The communication systems need to rapidly generate useful, robust, and secure alert notifications. Here we provide a general technical and seismological overview of ISNet's complex architecture and implementation.Published622-6344.1. Metodologie sismologiche per l'ingegneria sismicaJCR Journalreserve

Peripheral Purinergic Modulation in Pediatric Orofacial Inflammatory Pain Affects Brainstem Nitroxidergic System: A Translational Research

Physiology of orofacial pain pathways embraces primary afferent neurons, pathologic changes in the trigeminal ganglion, brainstem nociceptive neurons, and higher brain function regulating orofacial nociception. The goal of this study was to investigate the nitroxidergic system alteration at brainstem level (spinal trigeminal nucleus), and the role of peripheral P2 purinergic receptors in an experimental mouse model of pediatric inflammatory orofacial pain, to increase knowledge and supply information concerning orofacial pain in children and adolescents, like pediatric dentists and pathologists, as well as oro-maxillo-facial surgeons, may be asked to participate in the treatment of these patients. The experimental animals were treated subcutaneously in the perioral region with pyridoxalphosphate-6-azophenyl-2′,4′-disulphonic acid (PPADS), a P2 receptor antagonist, 30 minutes before formalin injection. The pain-related behavior and the nitroxidergic system alterations in the spinal trigeminal nucleus using immunohistochemistry and western blotting analysis have been evaluated. The local administration of PPADS decreased the face-rubbing activity and the expression of both neuronal and inducible nitric oxide (NO) synthase isoforms in the spinal trigeminal nucleus. These results underline a relationship between orofacial inflammatory pain and nitroxidergic system in the spinal trigeminal nucleus and suggest a role of peripheral P2 receptors in trigeminal pain transmission influencing NO production at central level. In this way, orofacial pain physiology should be elucidated and applied to clinical practice in the future

Stop-event-related potentials from intracranial electrodes reveal a key role of premotor and motor cortices in stopping ongoing movements

In humans, the ability to withhold manual motor responses seems to rely on a right-lateralized frontal–basal ganglia–thalamic network, including the pre-supplementary motor area and the inferior frontal gyrus (IFG). These areas should drive subthalamic nuclei to implement movement inhibition via the hyperdirect pathway. The output of this network is expected to influence those cortical areas underlying limb movement preparation and initiation, i.e., premotor (PMA) and primary motor (M1) cortices. Electroencephalographic (EEG) studies have shown an enhancement of the N200/P300 complex in the event-related potentials (ERPs) when a planned reaching movement is successfully stopped after the presentation of an infrequent stop-signal. PMA and M1 have been suggested as possible neural sources of this ERP complex but, due to the limited spatial resolution of scalp EEG, it is not yet clear which cortical areas contribute to its generation. To elucidate the role of motor cortices, we recorded epicortical ERPs from the lateral surface of the fronto-temporal lobes of five pharmacoresistant epileptic patients performing a reaching version of the countermanding task while undergoing presurgical monitoring. We consistently found a stereotyped ERP complex on a single-trial level when a movement was successfully cancelled. These ERPs were selectively expressed in M1, PMA, and Brodmann's area (BA) 9 and their onsets preceded the end of the stop process, suggesting a causal involvement in this executive function. Such ERPs also occurred in unsuccessful-stop (US) trials, that is, when subjects moved despite the occurrence of a stop-signal, mostly when they had long reaction times (RTs). These findings support the hypothesis that motor cortices are the final target of the inhibitory command elaborated by the frontal–basal ganglia–thalamic network

Biological Prognostic Value of miR-155 for Survival Outcome in Head and Neck Squamous Cell Carcinomas: Systematic Review, Meta-Analysis and Trial Sequential Analysis

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers worldwide; in fact, it is among the top six neoplasms, with an incidence of about 370,000 new cases per year. The 5-year survival rate, despite chemotherapy, radiotherapy, and surgery for stages 3 and 4 of the disease, is low. MicroRNAs (miRNAs) are a large group of small single-stranded non-coding endogenous RNAs, approximately 18–25 nucleotides in length, that play a significant role in the post-transcriptional regulation of genes. Recent studies investigated the tissue expression of miR-155 as a prognostic biomarker of survival in HNSCC. The purpose of this systematic review is, therefore, to investigate and summarize the current findings in the literature concerning the potential prognostic expression of tissue miR-155 in patients with HNSCC. The revision was performed according to PRISMA indications: three databases (PubMed, Scopus, and the Cochrane Register) were consulted through the use of keywords relevant to the revision topic. Totally, eight studies were included and meta-analyzed. The main results report for the aggregate HR values of 1.40 for OS, 1.36 for DFS, and 1.09 for DPS. Finally, a trial sequencing analysis was also conducted to test the robustness of the proposed meta-analysis