The ongoing interest in densely packed miniaturized electrode arrays for high-resolution epicortical recordings has induced many researchers to explore the use of nanomaterial coatings to reduce ...electrode impedance while increasing signal-to-noise ratio and charge injection capability. Although these materials are very effective, their use in clinical practice is strongly inhibited by concerns about the potential risks derived from the use of nanomaterials in direct contact with the human brain. In this work we propose a novel approach to safely couple nanocoated electrodes to the brain surface by encapsulating them with a biocompatible hydrogel. We prove that fibrin hydrogel coating over nanocoated high-density arrays of epicortical microelectrodes is electrically transparent and allows avoiding direct exposure of the brain tissue to the nanocoatings while maintaining all the advantages derived from the nanostructured electrode surface. This method may make available acute and sub-acute neural recordings with nanocoated high-resolution arrays for clinical applications.
The topographic map of motor cortical representation, called the motor map, is not invariant, but can be altered by motor learning, neurological injury, and functional recovery from injury. Although ...much attention has been paid to short-term changes of the motor map, robust measures have not been established. The existing mapping methods are time-consuming, and the obtained maps are confounded by time preference. The purpose of this study was to examine the dynamics of the motor map on a timescale of minutes during transient somatosensory input by a fast motor mapping technique. We applied 32-channel micro-electrocorticographic electrode arrays to the rat sensorimotor cortex for cortical stimulation, and the topographic profile of motor thresholds in forelimb muscle was identified by fast motor mapping. Sequential motor maps were obtained every few minutes before, during, and just after skin stimulation to the dorsal forearm using a wool buff. During skin stimulation, the motor map expanded and the center of gravity of the map was shifted caudally. The expansion of the map persisted for at least a few minutes after the end of skin stimulation. Although the motor threshold of the hotspot was not changed, the area in which it was decreased appeared caudally to the hotspot, which may be in the somatosensory cortex. The present study demonstrated rapid enlargement of the forelimb motor map in the order of a few minutes induced by skin stimulation. This helps to understand the spatial dynamism of motor cortical representation that is modulated rapidly by somatosensory input.
•Rat forelimb motor map expanded during a few minutes of skin brush stimulation.•The expansion of the motor map persisted for a few minutes after skin stimulation.•Motor threshold in the somatosensory cortex might be decreased by skin stimulation.
Purpose
Ruptured descending thoracic aorta (rDTA) is an harmful condition requiring emergent treatment. Thoracic endovascular aortic repair (TEVAR) is replacing the traditional open repair in the ...majority of descending thoracic aortic disease. An unanimous agreement regarding the optimal approach to treat rDTA has not been reached yet due to the lack of evidences supporting the improvement of long-term survival. The present meta-analysis of observational cohort studies aims to estimate the outcome of endovascular (TEVAR) versus surgical (OR) approach in the treatment of rDTA.
Methods
Prisma Statement for performing and reporting meta-analysis has been used. MEDLINE, Scopus and the Cochrane Library databases were searched. A meta-analysis of observational cohort studies that examined the outcomes after OR and TEVAR for the management of rDTA was performed.
Results
A total of 10,466 patients with rDTA were screened. Endovascular therapy was associated with a lower risk of in-hospital mortality compared with open repair (Risk RatioRR 0.63; 95% CI0.57–0.70). The risk of stroke rate was not statistically different between endovascular versus open approach (RR0.86; 95% CI0.62–1.19). Endovascular treatment had benefits on paraplegia (RR0.70; 95% CI0.55–0.91) and other neurological complications (RR0.24; 95% CI0.10–0.56). TEVAR was associated with lower renal failure, cardiac complications and vascular injuries. Late mortality (Hazard RatioHR 0.84; 95% CI0.63–1.13) and re-intervention rate (RR1.48; 95% CI0.80–2.74) were not significantly different between TEVAR and OR.
Conclusions
TEVAR seems to offer advantages in terms of early mortality and complications rate. Moreover, data on late mortality and re-intervention are encouraging to consider endovascular treatment comparable to open repair for acute thoracic aorta emergency on long-term follow-up.
Objective
Custodiol® and St. Thomas cardioplegia are widely employed in mini-thoracotomy mitral valve (MV) operations. One-dose of the former provides 3 h of myocardial protection. Conversely, St. ...Thomas solution is usually reinfused every 30 min and safety of single delivery is unknown. We aimed to compare single-shot St. Thomas versus Custodiol® cardioplegia.
Methods
Primary endpoint of the prospective observational study was cardiac troponin T level at different post-operative time-points. Propensity-weighted treatment served to adjust for confounding factors.
Results
Thirty-nine patients receiving St. Thomas were compared with 25 patients receiving Custodiol® cardioplegia; cross-clamping always exceeded 45 min. No differences were found in postoperative markers of myocardial injury. Ventricular fibrillation at the resumption of electric activity was more frequent following Custodiol® cardioplegia (
P
= .01).
Conclusion
Effective myocardial protection exceeding 1 h of ischemic arrest can be achieved with a single-dose St. Thomas cardioplegia in selected patients undergoing right mini-thoracotomy MV surgery.
Multi‐walled carbon nanotubes plastic actuator Biso, Maurizio; Ricci, Davide
Physica status solidi. B. Basic research,
December 2009, Letnik:
246, Številka:
11‐12
Journal Article, Conference Proceeding
Recenzirano
Carbon nanotubes (CNTs) have electrical and mechanical properties that make them highly attractive for actuators. They have the ability to deform elastically by several percent, thus storing very ...large amounts of energy, thanks to their crystalline nature and to their morphology. A bimorph actuator composed of single‐walled carbon nanotubes (SWCNTs), polyvinylidene difluoride (PVdF) and the ionic liquid (IL) 1‐butyl 3‐methylimidazolium tetrafluoroborate BMIMBF4 with a polymer‐supported internal IL electrolyte was previously demonstrated by Aida and coworkers. While several experiments were carried out using SWCNTs, PVdF and a number of ILs, the use of multi‐walled carbon nanotubes (MWCNTs) instead of SWCNTs is, to our knowledge, a new result that will be presented here. Electrochemical characterizations by cyclic voltammetry (CV), and actuation tests performed applying a square wave of 4 V peak‐to‐peak at frequencies between 0.3 and 2 Hz are reported and discussed.
Abstract
OBJECTIVES
Prosthetic valve endocarditis (PVE) is an uncommon yet dreadful complication in patients with prosthetic valves that requires a distinct analysis from native valve endocarditis. ...The present study aims to investigate independent risk factors for early surgical outcomes in patients with PVE.
METHODS
A retrospective cohort study was conducted in 8 Italian Cardiac Surgery Units from January 2000 to December 2013 by enrolling all PVE patients undergoing surgical treatment.
RESULTS
A total of 209 consecutive patients were included in the study. During the study period, the global rate of surgical procedures for PVE among all operations for isolated or associated valvular disease was 0.45%. Despite its rarity this percentage increased significantly during the second time frame (2007–2013) in comparison with the previous one (2000–2006): 0.58% vs 0.31% (P < 0.001). Intraoperative and in-hospital mortality rates were 4.3% and 21.5%, respectively. Logistic regression analysis identified the following factors associated with in-hospital mortality: female gender odds ratio (OR) = 4.62; P < 0.001, shock status (OR = 3.29; P = 0.02), previous surgical procedures within 3 months from the treatment (OR = 3.57; P = 0.009), multivalvular involvement (OR = 8.04; P = 0.003), abscess (OR = 2.48; P = 0.03) and urgent surgery (OR = 6.63; P < 0.001).
CONCLUSIONS
Despite its rarity, PVE showed a significant increase over time. Up to now, in-hospital mortality after surgical treatment still remains high (>20%). Critical clinical presentation and extension of anatomical lesions are strong preoperative predictors for poor early outcome.
Finding the most appropriate technology for building electrodes to be used for long term implants in humans is a challenging issue. What are the most appropriate technologies? How could one achieve ...robustness, stability, compatibility, efficacy, and versatility, for both recording and stimulation? There are no easy answers to these questions as even the most fundamental and apparently obvious factors to be taken into account, such as the necessary mechanical, electrical and biological properties, and their interplay, are under debate. We present here our approach along three fundamental parallel pathways: we reduced electrode invasiveness and size without impairing signal-to-noise ratio, we increased electrode active surface area by depositing nanostructured materials, and we protected the brain from direct contact with the electrode without compromising performance. Altogether, these results converge toward high-resolution ECoG arrays that are soft and adaptable to cortical folds, and have been proven to provide high spatial and temporal resolution. This method provides a piece of work which, in our view, makes several steps ahead in bringing such novel devices into clinical settings, opening new avenues in diagnostics of brain diseases, and neuroprosthetic applications.
Objective Reports of minimally invasive tricuspid valve operations are rare, and results are often contradictory. This study analyzes our 5-year experience with minimally invasive tricuspid valve ...operations in high-risk patients. Methods Between November 2005 and December 2011, tricuspid valve surgery using a nonsternotomy minimally invasive technique was performed in 64 patients (19 male, 45 female; mean age, 63.2 ± 12.8 years). Mean preoperative European System for Cardiac Operative Risk Evaluation was 7.3 ± 2.9, and predicted mortality was 11.6% ± 11.7%. Tricuspid valve regurgitation cause was functional in 36 patients (56.2%), endocarditis in 2 patients (3.1%), and rheumatic in 24 patients (37.5%). Two patients (3.1%) showed prosthesis dysfunction. Forty patients (62.5%) had undergone previous cardiac surgery. Results Tricuspid valve repair was performed in 35 patients (54.7%). Tricuspid valve replacement with bioprosthesis was performed in 27 patients (42.2%), and the remaining 2 patients (3.1%) underwent bioprosthetic replacement. Concomitant procedures (48) included mitral valve surgery (42 patients), atrial septal defect closure (5 patients), and myxoma exeresis (1 patient). Conversion to sternotomy occurred in 1 patient (1.6%). Overall hospital mortality was 7.9%. Stroke occurred in 1 patient (1.6%), and 5 patients underwent reoperation for bleeding (7.8%). Mean follow-up time was 21 ± 16 months (range, 1-59 months) and 100% completed. Cumulative Kaplan–Meier estimated 5-year survival was 81.3%, and 5-year freedom from reoperation was 100%. Conclusions The heart-port–based minimally invasive approach seems to be safe, feasible, and reproducible in case of tricuspid valve operations. It ensures low perioperative morbidity, moderate to low rates of tricuspid regurgitation recurrence, and low late mortality. It also seems to have an added value in case of reoperative procedures.
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