230 research outputs found

    Repetitive low-frequency stimulation reduces epileptiform synchronization in limbic neuronal networks.

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    Deep-brain electrical or transcranial magnetic stimulation may represent a therapeutic tool for controlling seizures in patients presenting with epileptic disorders resistant to antiepileptic drugs. In keeping with this clinical evidence, we have reported that repetitive electrical stimuli delivered at approximately 1 Hz in mouse hippocampus-entorhinal cortex (EC) slices depress the EC ability to generate ictal activity induced by the application of 4-aminopyridine (4AP) or Mg2+-free medium (Barbarosie, M., Avoli, M., 1997. CA3-driven hippocampal–entorhinal loop controls rather than sustains in vitro limbic seizures. J. Neurosci. 17, 9308–9314.). Here, we confirmed a similar control mechanism in rat brain slices analyzed with field potential recordings during 4AP (50 μM) treatment. In addition, we used intrinsic optical signal (IOS) recordings to quantify the intensity and spatial characteristics of this inhibitory influence. IOSs reflect the changes in light transmittance throughout the entire extent of the slice, and are thus reliable markers of limbic network epileptiform synchronization. First, we found that in the presence of 4AP, the IOS increases, induced by a train of electrical stimuli (10 Hz for 1 s) or by recurrent, single-shock stimulation delivered at 0.05 Hz in the deep EC layers, are reduced in intensity and area size by low-frequency (1 Hz), repetitive stimulation of the subiculum; these effects were observed in all limbic areas contained in the slice. Second, by testing the effects induced by repetitive subicular stimulation at 0.2–10 Hz, we identified maximal efficacy when repetitive stimuli are delivered at 1 Hz. Finally, we discovered that similar, but slightly less pronounced, inhibitory effects occur when repetitive stimuli at 1 Hz are delivered in the EC, suggesting that the reduction of IOSs seen during repetitive stimulation is pathway dependent as well as activity dependent. Thus, the activation of limbic networks at low frequency reduces the intensity and spatial extent of the IOS changes that accompany ictal synchronization in an in vitro slice preparation. This conclusion supports the view that repetitive stimulation may represent a potential therapeutic tool for controlling seizures in patients with pharmacoresistant epileptic disorders

    Factors shaping distribution and abundance of raptors wintering in two large Mediterranean islands

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    A growing number of ecological studies suggest that animal distributions are not only influenced by classical ecological features such as habitat availability, but also by the motion capacity of the studied animal. Here we analyse the diversity and density of two wintering raptor communities from Crete and Sicily, two large Mediterranean islands located along migratory flyways. We performed 611 and 1030 km of transects in Crete and Sicily respectively, examining the spatial distribution of raptors in relation to land use, topography, raptor species diversity and abundance. Our results show that community diversity and specific abundance are strictly related in accordance with the ‘More Individuals Hypothesis’. Comparing the two most common raptors, the density of the Eurasian kestrel was the highest in Sicily and that of the common buzzard in Crete. An overall positive effect of Eurasian kestrel density on that of the common buzzard was found in both islands, but higher in Crete. Our findings suggest that the distribution and density of the Eurasian kestrel, because of its higher movement ability, are less influenced by the presence of ecological barriers along potentially migratory flyways. We cannot exclude that higher inter specific competition with common buzzards in Crete might have pushed the smaller species to cross the Mediterranean Sea in order to overwinter in Africa

    Crosscultural Validation of the Community Integration Questionnaire-Revised in an Italian Population

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    Objective. The aims of this study are the translation, cultural adaptation, and validation of the Community Integration Questionnaire-Revised (CIQ-R) in Italian in a group of individuals with no clinical evidence of disability. Methods. The test's internal consistency and validity were assessed by following international guidelines. The test's internal consistency was examined using Cronbach's alpha (α) coefficient. Pearson's correlation coefficient was calculated to assess the test's concurrent validity compared with the Short Form-12 (SF-12) health survey. Results. The CIQ-R was administrated to 400 people with no clinical evidence of disease, impairment, or disability, aged between 18 and 64. Cronbach's α reported a value of 0.82 in the home integration subscale. The test also showed a good test-retest reliability, with an Intraclass Correlation Coefficient of 0.78, and a significant correlation between the total score of the CIQ-R and the Physical Component Summary (PCS) of the SF-12 (r=0.118), between the "social integration"subscale's score and PCS12 (r=0.121) and between the "Electronic Social Networking integration"subscale's score and PCS12 (r=0.184), with p<0.05. Conclusion. This is the first study to report the results of the translation and validation of the CIQ-R in Italian. The CIQ-R is an important tool for Italian professionals and can be useful in both clinical practice and research for measuring the level of community integration among the healthy population

    Comparison of indirect radiation dose estimates with directly measured radiation dose for patients and operators during complex endovascular procedures

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    BackgroundA great deal of attention has been directed at the necessity and potential for deleterious outcomes as a result of radiation exposure during diagnostic evaluations and interventional procedures. We embarked on this study in an attempt to accurately determine the amount of radiation exposure given to patients undergoing complex endovascular aortic repair. These measured doses were then correlated with radiation dose estimates provided by the imaging equipment manufacturers that are typically used for documentation and analysis of radiation-induced risk.MethodsConsecutive patients undergoing endovascular thoracoabdominal aneurysm (eTAAA) repair were prospectively studied with respect to radiation dose. Indirect parameters as cumulative air kerma (CAK), kerma area product (KAP), and fluoroscopy time (FT) were recorded concurrently with direct measurements of dose (peak skin dose [PSD]) and radiation exposure patterns using radiochromatic film placed in the back of the patient during the procedure. Simultaneously, operator exposure was determined using high-sensitivity electronic dosimeters. Correlation between the indirect and direct parameters was calculated. The observed radiation exposure pattern was reproduced in phantoms with over 200 dosimeters located in mock organs, and effective dose has been calculated in an in vitro study. Scatter plots were used to evaluate the relationship between continuous variables and Pearson coefficients.ResultseTAAA repair was performed in 54 patients over 5 months, of which 47 had the repair limited to the thoracoabdominal segment. Clinical follow-up was complete in 98% of the patients. No patients had evidence of radiation-induced skin injury. CAK exceeded 15 Gy in 3 patients (the Joint Commission on Accreditation of Healthcare Organizations [JCAHO] threshold for sentinel events); however, the direct measurements were well below 15 Gy in all patients. PSD was measured by quantifying the exposure of the radiochromatic film. PSD correlated weakly with FT but better with CAK and KAP (r = 0.55, 0.80, and 0.76, respectively). The following formula provides the best estimate of actual PSD = 0.677 + 0.257 CAK. The average effective dose was 119.68 mSv (for type II or III eTAAA) and 76.46 mSv (type IV eTAAA). The operator effective dose averaged 0.17 mSv/case and correlated best with the KAP (r = 0.82, P < .0001).ConclusionFT cannot be used to estimate PSD, and CAK and KAP represent poor surrogate markers for JCAHO-defined sentinel events. Even when directly measured PSDs were used, there was a poor correlation with clinical event (no skin injuries with an average PSD >2 Gy). The effective radiation dose of an eTAAA is equivalent to two preoperative computed tomography scans. The maximal operator exposure is 50 mSv/year, thus, a single operator could perform up to 294 eTAAA procedures annually before reaching the recommended maximum operator dose

    Perioperative cardiac events in endovascular repair of complex aortic aneurysms and association with preoperative studies

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    BackgroundEndovascular repair of complex aortic aneurysms (CAAs) can be performed in high-risk individuals, yet is still associated with significant morbidity, including spinal cord ischemia, cardiac complications, and death. This analysis was undertaken to better define the cardiac risk for CAA.MethodsA prospective database of patients undergoing thoracoabdominal or juxtarenal aortic aneurysm repair with branched and fenestrated endografts was used to retrospectively determine the number of cardiac events, defined as myocardial infarction (MI), atrial fibrillation (AF), and ventricular arrhythmia (VA), that occurred ≤30 days of surgery. Postoperative serial troponin measurements were performed in 266 patients. Any additional available cardiac information, including preoperative echocardiography, physiologic stress tests, and history of cardiac disease, was obtained from medical records. The efficacy of preoperative stress testing and the association of various echo parameters were evaluated in the context of cardiac outcomes using univariable and multivariable logistic regression models.ResultsBetween August 2001 and December 2007, 395 patients underwent endovascular repair of a thoracoabdominal or juxtarenal aortic aneurysm. The incidence of AF, VA, and 30-day cardiac-related death was 9%, 3%, and 2%, respectively. Overall 30-day mortality was 6%. Univariable analysis showed the presence of mitral annulus calcification was associated with MI (odds ratio [OR], 3.5; 95% confidence interval [CI], 0.9-13.8; P = .07). Left atrium cavity area, ejection fraction, left ventricle mass, and left ventricular mass index were univariably associated with the presence of VA. Multivariable analysis showed only the left atrium cavity area was independently associated with VA (OR, 1.2; 95% CI, 1.0-1.5; P = .07). Stress test was done in 179 patients. Negative stress test results occurred in 152 (85%), of whom 9 (6%) sustained an MI during the 30-day perioperative course. MI occurred in 2 of the 27 patients (7%) who had a positive stress test result.ConclusionsEndovascular repair of CAA can be performed in high-risk individuals but is associated with significant cardiac risk. It remains difficult to risk stratify patients using preoperative stress testing. Echo evaluation may help to identify patients who may be more likely to develop ventricular arrhythmias in the postoperative period and thus warrant closer monitoring. Postoperative troponin monitoring of all patients undergoing repair of CAA is warranted given the overall risk of MI

    Propagation of Epileptiform Events across the Corpus Callosum in a Cingulate Cortical Slice Preparation

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    We report on a novel mouse in vitro brain slice preparation that contains intact callosal axons connecting anterior cingulate cortices (ACC). Callosal connections are demonstrated by the ability to regularly record epileptiform events between hemispheres (bilateral events). That the correlation of these events depends on the callosum is demonstrated by the bisection of the callosum in vitro. Epileptiform events are evoked with four different methods: (1) bath application of bicuculline (a GABA-A antagonist); (2) bicuculline+MK801 (an NMDA receptor antagonist), (3) a zero magnesium extracellular solution (0Mg); (4) focal application of bicuculline to a single cortical hemisphere. Significant increases in the number of epileptiform events, as well as increases in the ratio of bilateral events to unilateral events, are observed during bath applications of bicuculline, but not during applications of bicuculline+MK-801. Long ictal-like events (defined as events >20 seconds) are only observed in 0Mg. Whole cell patch clamp recordings of single neurons reveal strong feedforward inhibition during focal epileptiform events in the contralateral hemisphere. Within the ACC, we find differences between the rostral areas of ACC vs. caudal ACC in terms of connectivity between hemispheres, with the caudal regions demonstrating shorter interhemispheric latencies. The morphologies of many patch clamped neurons show callosally-spanning axons, again demonstrating intact callosal circuits in this in vitro preparation

    Multicentre International Registry of Open Surgical Versus Percutaneous Upper Extremity Access During Endovascular Aortic Procedures

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    Objective: To investigate access failure (AF) and stroke rates of aortic procedures performed with upper extremity access (UEA), and compare results of open surgical vs. percutaneous UEA techniques with closure devices. Methods: A physician initiated, multicentre, ambispective, observational registry (SUPERAXA - NCT04589962) was carried out of patients undergoing aortic procedures requiring UEA, including transcatheter aortic valve replacement, aortic arch, and thoraco-abdominal aortic endovascular repair, pararenal parallel grafts, renovisceral and iliac vessel repair. Only vascular procedures performed with an open surgical or percutaneous (with a suture mediated vessel closure device) UEA were analysed. Risk factors and endpoints were classified according to the Society for Vascular Surgery and VARC-3 (Valve Academic Research Consortium) reporting standards. A logistic regression model was used to identify AF and stroke risk predictors, and propensity matching was employed to compare the UEA closure techniques. Results: Sixteen centres registered 1 098 patients (806 men [73.4%]; median age 74 years, interquartile range 69 – 79 years) undergoing vascular procedures using open surgical (76%) or percutaneous (24%) UEA. Overall AF and stroke rates were 6.8% and 3.0%, respectively. Independent predictors of AF by multivariable analysis included pacemaker ipsilateral to the access (odds ratio [OR] 3.8, 95% confidence interval [CI] 1.2 – 12.1; p =.026), branched and fenestrated procedure (OR 3.4, 95% CI 1.2 – 9.6; p =.019) and introducer internal diameter ≥ 14 F (OR 6.6, 95% CI 2.1 – 20.7; p =.001). Stroke was associated with female sex (OR 3.4, 95% CI 1.3 – 9.0; p =.013), vessel diameter > 7 mm (OR 3.9, 95% CI 1.1 – 13.8; p =.037), and aortic arch procedure (OR 7.3, 95% CI 1.7 – 31.1; p =.007). After 1:1 propensity matching, there was no difference between open surgical and percutaneous cohorts. However, a statistically significantly higher number of adjunctive endovascular procedures was recorded in the percutaneous cohort (p <.001). Conclusion: AF and stroke rates during complex aortic procedures employing UEA are non-negligible. Therefore, selective use of UEA is warranted. Percutaneous access with vessel closure devices is associated with similar complication rates, but more adjunctive endovascular procedures are required to avoid surgical exposure

    Individual variation in orientation promotes a 3000-km latitudinal change in wintering grounds in a long-distance migratory raptor

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    Migrating juvenile birds rely on endogenous information in choosing the direction in which to fly, but such input may be overridden by social interactions with experienced individuals. We tagged seven juvenile Short-toed Eagles Circaetus gallicus with GPS transmitters in southern Italy. This trans-Saharan migrant flies mainly by soaring and is therefore not well adapted to performing long water crossings. Five of the seven tagged juveniles used the longer but apparently safer route towards the Strait of Gibraltar, and two migrated along a southerly trajectory and subsequently spent the winter in Sicily, apparently forced to do so by the 150-km-wide Sicily Channel. One of these individuals took the longer route the following autumn. These results, combined with long-term (15 years) visual field observations involving thousands of individuals, suggest that inexperienced Short-toed Eagles may learn their migratory routes from experienced adults, whereas some of them migrate south in response to an innate orientation instinct. Transport costs, inherited information and geography apparently interact, forcing some Short-toed Eagles to winter 3000 km to the north of the majority of their conspecifics.The study has been funded by the Osservatorio Faunistico of Regione Basilicata through the Parco Regionale Gallipoli Cognato – Piccole Dolomiti Lucane
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