Mean Burst Research Articles

Basal ganglia dysfunction in OCD: subthalamic neuronal activity correlates with symptoms severity and predicts high-frequency stimulation efficacy

Functional and connectivity changes in corticostriatal systems have been reported in the brains of patients with obsessive–compulsive disorder (OCD); however, the relationship between basal ganglia activity and OCD severity has never been adequately established. We recently showed that deep brain stimulation of the subthalamic nucleus (STN), a central basal ganglia nucleus, improves OCD. Here, single-unit subthalamic neuronal activity was analysed in 12 OCD patients, in relation to the severity of obsessions and compulsions and response to STN stimulation, and compared with that obtained in 12 patients with Parkinson's disease (PD). STN neurons in OCD patients had lower discharge frequency than those in PD patients, with a similar proportion of burst-type activity (69 vs 67%). Oscillatory activity was present in 46 and 68% of neurons in OCD and PD patients, respectively, predominantly in the low-frequency band (1–8 Hz). In OCD patients, the bursty and oscillatory subthalamic neuronal activity was mainly located in the associative–limbic part. Both OCD severity and clinical improvement following STN stimulation were related to the STN neuronal activity. In patients with the most severe OCD, STN neurons exhibited bursts with shorter duration and interburst interval, but higher intraburst frequency, and more oscillations in the low-frequency bands. In patients with best clinical outcome with STN stimulation, STN neurons displayed higher mean discharge, burst and intraburst frequencies, and lower interburst interval. These findings are consistent with the hypothesis of a dysfunction in the associative–limbic subdivision of the basal ganglia circuitry in OCD's pathophysiology.

A Multi‐wavelength Fiber‐Optic Temperature‐Controlled Laser Soldering System for Upper Aerodigestive Tract Reconstruction

Laser soldering of a thick multilayer organ using conventional CO(2) lasers is ineffective. The purpose of this work was to develop a method for bonding the multilayer tissue of the upper aerodigestive tracts (UADT) without the need of sutures or stapling. Animal model. Academic research laboratory. The authors developed a multi-wavelength laser system, based on 2 fiber-optic lasers applied simultaneously. A highly absorbable CO(2) laser interacts with the muscular layer, and a nonabsorbable GaAs laser interacts with indocyanine-green solid albumin, placed between the mucosa and the muscular layer. The authors used an ex vivo porcine model to examine the capability of this system to effectively correct esophageal tears. The soldered esophagi burst pressure was >175 cm H(2)O (98% success rate) in 88 of the 90 experiments. A conventional CO(2) laser soldering resulted in insufficient bonding (mean burst pressure of 40 ± 7 cm H(2)O, n = 5), while the multi-wavelength laser system provided an ~9-fold tighter seal (359 ± 75.4 cm H(2)O, P < .0001, n = 15). Burst pressures after conventional suturing of the defect was significantly lower (106 ± 65.8 cm H(2)O, P < .001) than in the multi-wavelength laser system. Bonding of the UADT mucosa using a multi-wavelength, temperature-controlled laser soldering system can support significantly higher pressures then conventional CO(2) laser soldering and suture repair. The mean bonding pressure was 3.5-fold higher than the maximal swallowing pressure. Our findings provide a basis for implementation of new surgical tools for repair of esophageal perforations.

A novel Polymorphism Linked to Epilepsy Encoding a Missense Mutation in the Pre-M1 Region of a6 Subunits Alters the Gating, but not Trafficking, of GABAa Receptors

Charged residues in the pre-M1 region of Cys-loop ligand-gated ion channels affect current activation, desensitization and deactivation, suggesting that these interface residues may be involved in coupling agonist binding to channel gating. Mutations that affect function and/or expression of GABAA receptors (GABARs) have been associated with idiopathic generalized epilepsies (IGEs). The Parallel Sequence Profiling of Ion Channels in Epilepsy Project at Baylor College of Medicine funded by NINDS and NHGRI identified a novel single nucleotide polymorphism encoding a missense mutation, Q237R, in the GABAR α6 subunit in a patient with an IGE (http://www.hgsc.bcm.tmc.edu/project-medseq-r-ionchannel.hgsc). Homology modeling suggested that Q237R is located within the β10-M1linker or “pre-M1” segment of the N-terminal α6 subunit extracellular domain where it contributes to GABAR subunit-subunit interfaces. We studied gating properties and surface expression of wild type (wt) α6β2γ2 and mutant α6(Q237R)β2γ2 receptors expressed in HEK293T cells. Transient currents were evoked using ultrafast application of 400-µsec pulses of saturating GABA (1 mM) applied to excised outside-out macropatches. Peak amplitudes of α6(Q237R)β2γ2 currents were not reduced but α6(Q237R)β2γ2 currents had slower activation (∼1.9 msec), slower and more desensitization (∼60 %), and faster deactivation (∼2-fold) than wt currents. On-cell α6(Q237R)β2γ2 and α6β2γ2 single channel currents had similar mean open durations, but opening and burst frequencies were significantly higher for mutant than for wt currents. We assessed surface and total cellular expression of wt and mutant receptors using flow cytometry. Co-expression of α6(Q237R) with β2 and γ2L subunits resulted in no significant reduction in total or surface expression of any subunit. We concluded that this mutation alters gating, but not trafficking, of α6β2γ2 GABARs.

Comparison of a reusable with a disposable vessel-sealing device in a sheep model: efficacy and costs

To compare the efficacy of the new reusable vessel-sealing device MarSeal (KLS Martin, Tuttlingen, Germany) with the conventional standard disposable LigaSure device (Covidien-Valleylab, Boulder, CO) in an in vivo animal model. Prospective animal study. Center of Experimental Surgery at a university hospital. Thirteen sheep. The carotid and femoral arteries were dissected bilaterally and sealed randomly with MarSeal unilaterally and consecutively with LigaSure contralaterally in vivo. Afterward the burst pressure was determined for each artery. Sealing time, failure rate, and burst pressure. The mean diameter of all arteries sealed did not differ significantly between the two groups (MarSeal 5.40 mm vs. LigaSure 5.35 mm). The mean sealing time was significantly shorter with use of the reusable device (MarSeal 5.2 seconds vs. LigaSure 9.1 seconds). We did not find a significant difference in sealing failure rates between the groups (MarSeal 7.0% vs. LigaSure 9.1%). In addition, analysis of mean burst pressure did not reveal a significant difference between the different devices (MarSeal 429 mm Hg vs. LigaSure 484 mm Hg). There was no significant difference with respect to lateral thermal damage (MarSeal 0.91 cm vs. LigaSure 0.93 cm). In our in vivo animal study, the new reusable MarSeal device appears to be equivalently effective for vessel sealing when compared with the conventional disposable LigaSure device.

Comparison of Two Different Energy-Based Vascular Sealing Systems for the Hemostasis of Various Types of Arteries: A Porcine Model—Evaluation of Ligasure ForceTriad™

The ForceTriad™ generator has been recently developed. This new electrosurgical generator would demonstrate improved quality and efficiency in blood vessel sealing. To compare currently available 10-mm laparoscopic electrosurgical devices with the LigaSure™ Vessel Sealing System and ForceTriad generator (Valleylab, Inc., a division of Tyco Healthcare) for use in vessel sealing. Blood vessels of various types and diameters were harvested from alive four pigs using three instruments: LigaSure Atlas™ with LigaSure Vessel Sealing Generator (LSAt), LigaSure Atlas with ForceTriad Generator (LSAtFT), and Endoclip™ II (Autosuture, USSC; a division of Tyco Healthcare). A total of 100 arteries were processed by removal of fatty and connective tissue from the adventitia before sealing. An additional set of specimens was sealed and histopathologically analyzed after being stained with hematoxylin and eosin. The mean burst pressure was significantly higher with LSAtFT compared to LSAt (P < 0.01). The sealing process was significantly shorter with LSAtFT (P < 0.05). With regard to the degree of thermal injury, adventitial collagen denaturation and proximal thermal injury to the smooth muscle in the media of the vessel wall were less common with LSAtFT; however, the numbers were too small for statistical analysis. Both the LSAt and LSAtFT secured all vessel sizes to well above physiologic levels. The LSAtFT could be used more confidently in vessels up to 7 mm. Our findings indicate that LSAtFT could be a safer and more efficient instrument for advanced laparoscopic surgery.

Activation of the K(ATP) channel by Mg-nucleotide interaction with SUR1.

The mechanism of adenosine triphosphate (ATP)-sensitive potassium (KATP) channel activation by Mg-nucleotides was studied using a mutation (G334D) in the Kir6.2 subunit of the channel that renders KATP channels insensitive to nucleotide inhibition and has no apparent effect on their gating. KATP channels carrying this mutation (Kir6.2-G334D/SUR1 channels) were activated by MgATP and MgADP with an EC50 of 112 and 8 µM, respectively. This activation was largely suppressed by mutation of the Walker A lysines in the nucleotide-binding domains of SUR1: the remaining small (∼10%), slowly developing component of MgATP activation was fully inhibited by the lipid kinase inhibitor LY294002. The EC50 for activation of Kir6.2-G334D/SUR1 currents by MgADP was lower than that for MgATP, and the time course of activation was faster. The poorly hydrolyzable analogue MgATPγS also activated Kir6.2-G334D/SUR1. AMPPCP both failed to activate Kir6.2-G334D/SUR1 and to prevent its activation by MgATP. Maximal stimulatory concentrations of MgATP (10 mM) and MgADP (1 mM) exerted identical effects on the single-channel kinetics: they dramatically elevated the open probability (PO > 0.8), increased the mean open time and the mean burst duration, reduced the frequency and number of interburst closed states, and eliminated the short burst states. By comparing our results with those obtained for wild-type KATP channels, we conclude that the MgADP sensitivity of the wild-type KATP channel can be described quantitatively by a combination of inhibition at Kir6.2 (measured for wild-type channels in the absence of Mg2+) and activation via SUR1 (determined for Kir6.2-G334D/SUR1 channels). However, this is not the case for the effects of MgATP.

Diffusion dynamics and first passage time in a two-coupled pendulum system

We present the numerical investigation of diffusion process and features of first passage time (FPT) and mean FPT (MFPT) in a two-coupled damped and periodically driven pendulum system. The effect of amplitude of the external periodic force and phase of the force on diffusion constant, distribution of FPT, P(tFPT), and MFPT is analyzed. Normal diffusion is found. Diffusion constant is found to show power-law variation near intermittency and sudden widening crises while linear variation is observed in the quasiperiodic region. In the intermittency crisis the divergence of diffusion constant is similar to the divergence of mean bursting length. P(tFPT) of critical distances of state variable exhibit periodic multiple peaks with decaying amplitude. MFPT of critical distances also follows power-law variation. Diffusion constant and MFPT are sensitive to the phase factor of the periodic force.

Daily muscle activity and quiescence in non-frail, pre-frail, and frail older women

Reduced muscle mass and strength are likely fundamental components of frailty. The purpose of this study was to measure daily muscle activity and quiescence in non-frail, pre-frail, and frail older women using portable electromyography (EMG). Thirty-three community-dwelling older Greek women were categorized as non-frail ( n = 10, 74 ± 4 years), pre-frail ( n = 11, 75 ± 4 years), and frail ( n = 12, 81 ± 6 years) based upon the frailty phenotype. Surface EMG over a 9-hour typical day was recorded from the biceps brachii, triceps brachii, vastus lateralis, and biceps femoris of the dominant side. Burst and gap analysis was used to quantify muscle activity and quiescence. The total duration of the muscles that were active (~ 2.5 h) and quiescent (~ 4 h) did not differ across frailty groups. However, the number of bursts was 28% fewer and the mean burst duration was 26% longer in frail women compared with the non-frail women. In addition, muscle activity was greater in the arm muscles than the thigh muscles across all groups (e.g. ~ 60% greater burst percentage). Burst number and duration indicate that muscle activity differs across stages of frailty in older women and is greater in the upper compared with lower limbs.

Stable operation of IEEE 802.11e EDCA: Interaction between offered load and MAC parameters

In this paper, we study impacts of TXOP allocation and AIFS parameter on one hop IEEE 802.11e EDCA network under varying offered load. Offered load is modified by changing the parameters of arrival process and node populations. Arrival process is varied by altering burst size distribution, mean burst size, frame size, and arrival rates. We investigate the effects of the offered load parameters on the network stability and non-saturation boundaries of IEEE 802.11e EDCA. Our results show interaction of offered load and MAC parameters. The results suggest the range of network parameters which preserve network stability and still achieve QoS differentiation.

Efficacy and safety of 5-mm-diameter bipolar and ultrasonic shears for cutting carotid arteries of the hybrid pig

Experimental data about the efficacy and safety of sealing devices are rare. Therefore, this study investigated these parameters for three commercially available energy-based vascular sealing and cutting systems. In male hybrid pigs, 487 carotid artery segments were sealed and cut using the harmonic scalpel or several bipolar sealing devices. The sealing failure rate, burst pressure, process time, and extent of lateral thermal damage were analyzed. A regular sealing and cutting process in more than 90% of the carotid arteries was found using the following instruments: LS1520, ACE (level 1), ACE (level 3), CS14C (level 1), WAVE (level 1), and WAVE (level 5). The largest failure rate was found for the CS14C device (level 5: initial sealing failure, 21.5%). The maximal mean burst pressure (1727±453 mmHg) was reached using the ACE device (level 1). Significant differences were found in the size of the lateral thermal damage, which a ranged from 2.5 mm (LS1520) to 1.51 mm (CS14C, level 1). The process time ranged widely from 6.8 s (ACE, level 5) to 31.83 s (WAVE, level 1). The current study demonstrated that all the tested devices are efficacious and safe in sealing and cutting arteries up to 5 mm in diameter. All the devices showed supraphysiologic mean burst pressures. Differences in failure rate, thermal damage, and process time lead to an advised application of the different systems.

Endoscopic full-thickness resection and defect closure in the colon

Endoscopic full-thickness resection (eFTR) is a minimally invasive method for en bloc resection of GI lesions. The aim of this pilot study was to evaluate the feasibility of a grasp-and-snare technique for eFTR combined with an over-the-scope clip (OTSC) for defect closure. Nonsurvival animal study. Animal laboratory. Fourteen female domestic pigs. The eFTR was performed in porcine colons using a novel tissue anchor in combination with a standard monofilament snare and 14 mm OTSC. In the first group (n = 20), closure of the colonic defects with OTSC was attempted after the resection. In the second group (n = 8), an endoloop was used to secure the resection base before eFTR was performed. In the first group (n = 20), eFTR specimens ranged from 2.4 to 5.5 cm in diameter. Successful closure was achieved in 9 out of 20 cases. Mean burst pressure for OTSC closure was 29.2 mm Hg (range, 2-90; SD, 29.92). Injury to adjacent organs occurred in 3 cases. Lumen obstruction due to the OTSC closure occurred in 3 cases. In the second group (n = 8), the diameter of specimens ranged from 1.2 to 2.2 cm. Complete closure was achieved in all cases, with a mean burst pressure of 76.6 mm Hg (range, 35-120; SD, 31). Lumen obstruction due to the endoloop closure occurred in one case. No other complications or injuries were observed in the second group. Nonsurvival setting. Colonic eFTR using the grasp-and-snare technique is feasible in an animal model. Ligation of the resection base with an endoloop before eFTR seems to reduce complication rates and improve closure success and leak test results despite yielding smaller specimens.

Performance Comparison of Packet-Level Multiplexing Algorithms with Bursty Traffic

Packet-based networks have opened the possibility of carrying a great variety of applications with different traffic profiles. Traffic profiles such as bursty traffic is essential for the analysis and evaluation of network performance. This paper is a simulation study devoted to comparing the performance of a range of packet-level multiplexing algorithms with bursty traffic. Four multiplexing algorithms are studied: round robin, random selection, weighted random selection and longest queue. Bursty traffic in this study is specified using two parameters: average packet rate and mean burst length. The algorithms performance has been measured in terms of three performance measures: average delay, delay variation and packet loss. The performance of multiplexing algorithms deteriorated when traffic intensity and burstiness of traffic increase. The algorithms competed between each other. Each algorithm showed better performance for a certain measure, however, with the expense of deterioration in other performance measures.

Influence of vagal afferents on supraspinal and spinal respiratory activity following cervical spinal cord injury in rats

C(2) spinal hemisection (C2HS) interrupts ipsilateral bulbospinal pathways and induces compensatory increases in contralateral spinal and possibly supraspinal respiratory output. Our first purpose was to test the hypothesis that after C2HS contralateral respiratory motor outputs become resistant to vagal inhibitory inputs associated with lung inflation. Bilateral phrenic and contralateral hypoglossal (XII) neurograms were recorded in anesthetized and ventilated rats. In uninjured (control) rats, lung inflation induced by positive end-expired pressure (PEEP; 3-9 cmH(2)O) robustly inhibited both phrenic and XII bursting. At 2 wk post-C2HS, PEEP evoked a complex response associated with phrenic bursts of both reduced and augmented amplitude, but with no overall change in the mean burst amplitude. PEEP-induced inhibition of XII bursting was still present but was attenuated relative to controls. However, by 8 wk post-C2HS PEEP-induced inhibition of both phrenic and XII output were similar to that in controls. Our second purpose was to test the hypothesis that vagal afferents inhibit ipsilateral phrenic bursting, thereby limiting the incidence of the spontaneous crossed phrenic phenomenon in vagal-intact rats. Bilateral vagotomy greatly enhanced ipsilateral phrenic bursting, which was either weak or absent in vagal-intact rats at both 2 and 8 wk post-C2HS. We conclude that 1) compensatory increases in contralateral phrenic and XII output after C2HS blunt the inhibitory influence of vagal afferents during lung inflation and 2) vagal afferents robustly inhibit ipsilateral phrenic bursting. These vagotomy data appear to explain the variability in the literature regarding the onset of the spontaneous crossed phrenic phenomenon in spontaneously breathing (vagal intact) vs. ventilated (vagotomized) preparations.

1236 AN AUTOLOGOUS TISSUE-ENGINEERED ENDOTHELIALIZED GRAFT: A POSSIBLE OPTION IN THE SURGICAL CORRECTION OF PEYRONIE'S DESEASE

You have accessJournal of UrologyTrauma/Reconstruction: Trauma & Reconstructive Surgery IV1 Apr 20101236 AN AUTOLOGOUS TISSUE-ENGINEERED ENDOTHELIALIZED GRAFT: A POSSIBLE OPTION IN THE SURGICAL CORRECTION OF PEYRONIE'S DESEASE Annie Imbeault, Geneviève Bernard, Gabrielle Ouellet, Sara Bouhout, and Stéphane Bolduc Annie ImbeaultAnnie Imbeault More articles by this author , Geneviève BernardGeneviève Bernard More articles by this author , Gabrielle OuelletGabrielle Ouellet More articles by this author , Sara BouhoutSara Bouhout More articles by this author , and Stéphane BolducStéphane Bolduc More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.759AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Surgical treatment is indicated in severe cases of Peyronie's disease. Incision of the plaque with subsequent graft material is the option of choice. Ideal graft tissue is not yet available. The aim of this study is to evaluate the use of an autologous tissue-engineered endothelialized graft by the self-assembly method for tunica albuginea reconstruction in Peyronie's disease. METHODS Two tunica albuginea models were created. Human fibroblasts were isolated from a small skin biopsy and cultured in vitro until formation of fibroblast sheets. After 4 weeks of maturation, umbilical vein endothelial cells (HUVEC) were seeded on fibroblasts sheets. It was then wrapped around a tubular support to form a cylinder of about 10 layers. After 21 days of tube maturation, HUVEC were seeded into the lumen of the fibroblast tubes for the endothelialized tunica albuginea model (ETA). No HUVEC were seeded into the lumen for the tunica albuginea model (TA). Both constructs were placed in a bioreactor for one week with an internal perfusion of endothelial cells culture medium (EGM-2). External perfusion with DME supplemented with 10% SVF was used for fibroblast culture. Fibroblast-only construct were used as controls. Histology, immunohistochemistry and burst pressure were performed to characterize mature tubular graft. Tubes with and without endothelial cells were also grafted on nude mice to evaluate the effects of endothelial cells. RESULTS Histology showed uniform multilayer of fibroblasts. Extracellular matrix, produced entirely by fibroblasts, presented a good staining for collagen 1 (positive anti-collagen 1). For the TA model, anti-human von Willebrand antibody revealed the endothelial cells forming capillary-like structures. TA model and ETA model reached a burst pressure of 584 mmHg and 728 mmHg respectively. Fibroblast-only tube had a mean burst pressure of 1761 ± 248 mmHg. On animal studies, tubes with endothelial cells were clearly more vascularized than tubes with fibroblasts only at day 7 and 14. CONCLUSIONS This tissue-engineered endothelialized tubular graft is structurally similar to normal tunica albuginea and presents an adequate mechanical resistance. The self-assembly method used and the autologous property of this model represent a real advantage comparatively to other available grafts. Next experiences will include comparison of the two proposed models on animal models. Quebec, Canada© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e478 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Annie Imbeault More articles by this author Geneviève Bernard More articles by this author Gabrielle Ouellet More articles by this author Sara Bouhout More articles by this author Stéphane Bolduc More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Natural orifice transluminal endoscopic surgery gastrotomy closure in porcine explants with the Padlock-G clip using the Lock-It system

The success of transgastric surgery depends on reliable, secure closure of the gastrotomy. Few tests of the integrity of these closures have been published. This study aimed to determine whether a gastrotomy suitable for a NOTES procedure can be closed safely and effectively from within the stomach using a novel endoscopically placed device, the Padlock-G with the Lock-It delivery system. In a series of eight consecutive porcine gastric explants gastrotomy was performed in an ex vivo animal laboratory, the gastrotomy being closed with the Padlock-G followed by burst pressure testing after completion of the procedure. Gastrotomies were made in porcine explants. T-tags were placed on either side of the gastrotomy, and, with the T-tags pulled into an endoscopic cap, the Padlock-G was deployed. Gastric transmural pressure gradients at bursting of these closures were measured during insufflation of the explanted stomachs with a high-pressure insufflator. The mean burst pressure of the gastrotomy closures was 68.0 mm Hg (range: 45 - 107 mm Hg). All of the stomachs ultimately ruptured at the closure sites, with the exception of the stomach that ruptured at the highest value (107 mm Hg), which ruptured at a site approximately 5 cm away from the closure site. All of the closures were accomplished in 30 minutes or less. The Padlock-G clip provides a secure gastric closure for natural-orifice surgery.

Seal properties of TachoSil(R): in vitro hemodynamic measurements

Fibrin glue products and collagen patches are frequently used as a sealing product, preventing surgical side bleedings. This is especially true in the field of cardiovascular surgery, where increasing numbers of patients are being operated with antiplatelet and anticoagulation therapy. The aim of this report was, in an in vitro hemodynamic setting, to examine the sealant properties of the TachoSil (Nycomed Pharma, Linz, Austria) patch. Burst pressure and normal force of 15 TachoSil sealed defects were measured. This was determined in a closed hydraulic system. Mean burst pressure load for a 5-mm defect was 69+/-11.4 mmHg; for a 7-mm defect was 63+/-16 mmHg; and, 62+/-16 mmHg for the defect with a diameter of 10 mm (P>0.05). The mean calculated normal force was as follows: 0.91+/-0.15 N for the 5 mm defect, 6.5+/-1.6 N for the 7 mm, and 8.1+/-0.75 N for the 10 mm defect. The TachoSil patch has the capability to seal small defects. However, at the larger defects the seal character was significantly reduced. These results suggest that the device may be a good alternative for hemostasis for small defects. The capacity to curtail or stop hemorrhage at the larger defects is unlikely.

An acoustic study of Georgian stop consonants

This study investigates the acoustic properties of ejective, voiced and voiceless aspirated stops in Georgian, a Caucasian language, and seeks to answer two questions: (i) Which acoustic features discriminate the three stop types? and (ii) Do Georgian stops undergo initial strengthening, and if so, is it syntagmatic or paradigmatic strengthening? Five female speakers were recorded reading words embedded in carrier phrases and stories. Acoustic measures include closure duration, voicing during the closure, voicing lag, relative burst intensity, spectral moment of bursts, phonation (H1-H2) and F0. Of these, voicing lag, voicing during the closure, mean burst frequency, H1-H2 and F0 could all be used to discriminate stop type, but stop types did not differ in closure duration or relative burst intensity. Georgian stops did show initial strengthening and showed only syntagmatic enhancement, not paradigmatic enhancement. Stops showed longer closure durations, longer voicing lags, and higher H1-H2 values in higher prosodic positions.

Second Prize: A Sealed Bladder Cuff Technique During Laparoscopic Nephroureterectomy Utilizing the LigaSure™ Electrosurgical Device: Laboratory and Clinical Experience

Laparoscopic nephroureterectomy (LNU) is a safe, minimally invasive approach for management of upper tract urothelial tumors. Controversy exists over the optimal technique for the distal ureter and bladder cuff (DUBC) excision. We examined the novel technique of using the LigaSure bipolar electrosurgical device in laboratory investigations and during clinical LNU to manage the DUBC. Initial investigations were undertaken in the porcine model. Areas of both normal porcine ureters and bladders, and ex vivo human ureters from radical nephrectomy specimens were sealed with the LigaSure and stained with nicotinamide adenine dinucleotide (NADH) and hematoxylin and eosin to examine the length of treatment effect and the viability of the ablated tissue. Clinically, we performed 22 LNU for proximal urothelial tumors using the LigaSure for the management of the DUBC. Intraoperative cystoscopy assessed cuff resection and bladder leakage. On postoperative day 10, a cystogram was performed. In the porcine model, the technique sealed the bladder effectively with a mean burst pressure of 14 mm Hg. Cellular staining revealed no viable urothelial tissue in the seal area and an additional 2 mm outside this area. Eighteen patients had a successful seal/ablation intraoperatively. Cystoscopy revealed cautery artifact and blanching over the former position of the ureteral orifice. The LigaSure device ablates and seals urothelial tissue with no viable cells in the clamped and adjacent blanched tissue. Our technique is technically feasible, removes an adequate bladder cuff, typically maintains a closed urinary system, and adheres to sound oncological principles. This procedure could be performed in both laparoscopic and open nephroureterectomy for proximal upper tract transitional cell tumors.

Phrenic nerve afferent activation of neurons in the cat SI cerebral cortex.

Stimulation of respiratory afferents elicits neural activity in the somatosensory region of the cerebral cortex in humans and animals. Respiratory afferents have been stimulated with mechanical loads applied to breathing and electrical stimulation of respiratory nerves and muscles. It was hypothesized that stimulation of the phrenic nerve myelinated afferents will activate neurons in the 3a and 3b region of the somatosensory cortex. This was investigated in cats with electrical stimulation of the intrathoracic phrenic nerve and C(5) root of the phrenic nerve. The somatosensory cortical response to phrenic afferent stimulation was recorded from the cortical surface, contralateral to the phrenic nerve, ispilateral to the phrenic nerve and with microelectrodes inserted into the cortical site of the surface dipole. Short-latency, primary cortical evoked potentials (1 degrees CEP) were recorded with stimulation of myelinated afferents of the intrathoracic phrenic nerve in the contralateral post-cruciate gyrus of all animals (n = 42). The mean onset and peak latencies were 8.5 +/- 5.7 ms and 21.8 +/- 9.8 ms, respectively. The rostro-caudal surface location of the 1 degrees CEP was found between the rostral edge of the post-cruciate dimple (PCD) and the rostral edge of the ansate sulcus, medio-lateral location was between 2 mm lateral to the sagittal sulcus and the lateral end of the cruciate sulcus. Histological examination revealed that the 1 degrees CEP sites were recorded over areas 3a and 3b of the SI somatosensory cortex. Intracortical activation of 16 neurons with two patterns of neural activity was recorded: (1) short-latency, short-duration activation of neurons and (2) long-latency, long-duration activation of neurons. Short-latency neurons had a mean onset latency of 10.4 +/- 3.1 ms and mean burst duration of 10.1 +/- 3.2 ms. The short-latency units were recorded at an average depth of 1.7 +/- 0.5 mm below the cortical surface. The long-latency neurons had a mean onset latency of 36.0 +/- 4.2 ms and mean burst duration of 32.2 +/- 8.4 ms. The long-latency units were recorded at an average depth of 2.4 +/- 0.2 mm below the cortical surface. The results of the study demonstrated that phrenic nerve afferents have a short-latency central projection to the SI somatosensory cortex. The phrenic afferents activated neurons in lamina III and IV of areas 3a and 3b. The cortical representation of phrenic nerve afferents is medial to the forelimb, lateral to the hindlimb, similar to thoracic loci, hence the phrenic afferent SI site in the cat homunculus is consistent with body position (thoracic region) rather than spinal segment (C(5)-C(7)). The phrenic afferent activation of the somatosensory cortex is bilateral, with the ipsilateral cortical activation occurring subsequent to the contralateral. These results support the hypothesis that phrenic afferents provide somatosensory information to the cerebral cortex which can be used for diaphragmatic proprioception and somatosensation.

Experimental investigation on spontaneously active hippocampal cultures recorded by means of high-density MEAs: analysis of the spatial resolution effects

Based on experiments performed with high-resolution Active Pixel Sensor microelectrode arrays (APS-MEAs) coupled with spontaneously active hippocampal cultures, this work investigates the spatial resolution effects of the neuroelectronic interface on the analysis of the recorded electrophysiological signals. The adopted methodology consists, first, in recording the spontaneous activity at the highest spatial resolution (interelectrode separation of 21 μm) from the whole array of 4096 microelectrodes. Then, the full resolution dataset is spatially downsampled in order to evaluate the effects on raster plot representation, array-wide spike rate (AWSR), mean firing rate (MFR) and mean bursting rate (MBR). Furthermore, the effects of the array-to-network relative position are evaluated by shifting a subset of equally spaced electrodes on the entire recorded area. Results highlight that MFR and MBR are particularly influenced by the spatial resolution provided by the neuroelectronic interface. On high-resolution large MEAs, such analysis better represent the time-based parameterization of the network dynamics. Finally, this work suggest interesting capabilities of high-resolution MEAs for spatial-based analysis in dense and low-dense neuronal preparation for investigating signaling at both local and global neuronal circuitries.