Adjuvants influence the immune cell populations present at the injection site granuloma induced by whole-cell inactivated paratuberculosis vaccines in sheep.

Vaccination is the most effective tool for paratuberculosis control. Currently, available vaccines prevent the progression of clinical disease in most animals but do not fully protect them against infection and induce the formation of an injection site granuloma. The precise mechanisms that operate in response to vaccination and granuloma development, as well as the effect that adjuvants could trigger, have not been fully investigated. Therefore, this study aimed to investigate the injection site granulomas induced by two inactivated paratuberculosis vaccines, which differ in the adjuvant employed. Two groups of 45-day-old lambs were immunized with two commercially available vaccines-one (n = 4) with Gudair® and the other (n = 4) with Silirum®. A third group (n = 4) was not vaccinated and served as control. The peripheral humoral response was assessed throughout the study by a commercial anti-Mycobacterium avium subspecies paratuberculosis (Map) antibody indirect ELISA, and the cellular immune response was assessed similarly by the IFN-γ release and comparative intradermal tests. The injection site granulomas were measured during the experiment and sampled at 75 days post-vaccination (dpv) when the animals were euthanized. The tissue damage, antigen and adjuvant distribution, and the presence and amount of immune cells were then determined and assessed by immunohistochemical methods. Antibodies against Map antigens; a general macrophage marker (Iba1), M1 (iNOS), and M2 (CD204) macrophages; T (CD3), B (CD20), and γδ T lymphocytes, proteins MHC-II and NRAMP1, and cytokines IL-4, IL-10, TNF, and IFN-γ were employed. Silirum® elicited a stronger peripheral cellular immune response than Gudair®, while the latter induced larger granulomas and more tissue damage at the site of injection. Additionally, adjuvant and Map antigen distribution throughout the granulomatous inflammatory infiltrate, as well as the NRAMP1 cell expression, which is linked to antigen phagocytosis, were highly irregular. In Silirum® induced granulomas, a higher number of MHC-II and TNF-expressing cells and a lower number of M2 macrophages suggested an improved antigen presentation, which could be due to the better antigen distribution and reduced tissue damage induced by this vaccine.

Sonic Hedgehog is expressed by hilar mossy cells and regulates cellular survival and neurogenesis in the adult hippocampus.

Sonic hedgehog (Shh) is a multifunctional signaling protein governing pattern formation, proliferation and cell survival during embryogenesis. In the adult brain, Shh has neurotrophic function and is implicated in hippocampal neurogenesis but the cellular source of Shh in the hippocampus remains ill defined. Here, we utilize a gene expression tracer allele of Shh (Shh-nlacZ) which allowed the identification of a subpopulation of hilar neurons known as mossy cells (MCs) as a prominent and dynamic source of Shh within the dentate gyrus. AAV-Cre mediated ablation of Shh in the adult dentate gyrus led to a marked degeneration of MCs. Conversely, chemical stimulation of hippocampal neurons using the epileptogenic agent kainic acid (KA) increased the number of Shh+ MCs indicating that the expression of Shh by MCs confers a survival advantage during the response to excitotoxic insults. In addition, ablation of Shh in the adult dentate gyrus led to increased neural precursor cell proliferation and their migration into the subgranular cell layer demonstrating that MCs-generated Shh is a key modulator of hippocampal neurogenesis.

Self-propagating, non-synaptic epileptiform activity recruits neurons by endogenous electric fields.

It is well documented that synapses play a significant role in the transmission of information between neurons. However, in the absence of synaptic transmission, neural activity has been observed to continue to propagate. Previous studies have shown that propagation of epileptiform activity takes place in the absence of synaptic transmission and gap junctions and is outside the range of ionic diffusion and axonal conduction. Computer simulations indicate that electric field coupling could be responsible for the propagation of neural activity under pathological conditions such as epilepsy. Electric fields can modulate neuronal membrane voltage, but there is no experimental evidence suggesting that electric field coupling can mediate self-regenerating propagation of neural activity. Here we examine the role of electric field coupling by eliminating all forms of neural communications except electric field coupling with a cut through the neural tissue. We show that 4-AP induced activity generates an electric field capable of recruiting neurons on the distal side of the cut. Experiments also show that applied electric fields with amplitudes similar to endogenous values can induce propagating waves. Finally, we show that canceling the electrical field at a given point can block spontaneous propagation. The results from these in vitro electrophysiology experiments suggest that electric field coupling is a critical mechanism for non-synaptic neural propagation and therefore could contribute to the propagation of epileptic activity in the brain.

Slow periodic activity in the longitudinal hippocampal slice can self-propagate non-synaptically by a mechanism consistent with ephaptic coupling.

KEY POINTS: Slow periodic activity can propagate with speeds around 0.1 m s-1 and be modulated by weak electric fields. Slow periodic activity in the longitudinal hippocampal slice can propagate without chemical synaptic transmission or gap junctions, but can generate electric fields which in turn activate neighbouring cells. Applying local extracellular electric fields with amplitude in the range of endogenous fields is sufficient to modulate or block the propagation of this activity both in the in silico and in the in vitro models. Results support the hypothesis that endogenous electric fields, previously thought to be too small to trigger neural activity, play a significant role in the self-propagation of slow periodic activity in the hippocampus. Experiments indicate that a neural network can give rise to sustained self-propagating waves by ephaptic coupling, suggesting a novel propagation mechanism for neural activity under normal physiological conditions. ABSTRACT: Slow oscillations are a standard feature observed in the cortex and the hippocampus during slow wave sleep. Slow oscillations are characterized by low-frequency periodic activity (<1 Hz) and are thought to be related to memory consolidation. These waves are assumed to be a reflection of the underlying neural activity, but it is not known if they can, by themselves, be self-sustained and propagate. Previous studies have shown that slow periodic activity can be reproduced in the in vitro preparation to mimic in vivo slow oscillations. Slow periodic activity can propagate with speeds around 0.1 m s-1 and be modulated by weak electric fields. In the present study, we show that slow periodic activity in the longitudinal hippocampal slice is a self-regenerating wave which can propagate with and without chemical or electrical synaptic transmission at the same speeds. We also show that applying local extracellular electric fields can modulate or even block the propagation of this wave in both in silico and in vitro models. Our results support the notion that ephaptic coupling plays a significant role in the propagation of the slow hippocampal periodic activity. Moreover, these results indicate that a neural network can give rise to sustained self-propagating waves by ephaptic coupling, suggesting a novel propagation mechanism for neural activity under normal physiological conditions.

Anestesia loco regional más sedación con dexmedetomidina para cirugía de Mohs con reconstrucción / Local - regional anesthesia with dexmedetomidine sedation for Mohs surgery and reconstruction

Resumen Introducción: La cirugía micrográfica de Mohs se emplea para la escisión de tumores cutáneos malignos y frecuentemente es seguida de reconstrucción, prolongando el procedimiento y causando ansiedad y molestia al paciente. Esta cirugía se realiza con anestesia local y sedación complementaria. Dentro de los anestésicos intravenosos la dexmedetomidina es una excelente opción; sin embargo, se han reportado casos de bradicardia severa asociado a inestabilidad hemodinámica y riesgo de complicaciones con su uso. Objetivo: Describir la frecuencia de bradicardia con repercusión hemodinámica en pacientes llevados a cirugía micrográfica de Mohs más reconstrucción, bajo anestesia loco regional y sedación con dexmedetomidina. Métodos: Estudio observacional descriptivo retrospectivo de 30 pacientes llevados a cirugía de Mohs entre el 1 de noviembre 2012 a 30 de noviembre de 2013. Resultados: El 53,3 % eran mujeres, la edad promedio fue de 68,4 años, 21,4 % fueron clasificados como ASA I, 53,5 % ASA II y 25 % ASA III. El tiempo quirúrgico promedio fue de 184 ± 61 minutos y de anestesia con dexmedetomidina fue 196 ± 65,2 minutos. Solo un paciente requirió atropina durante la cirugía y ningún paciente requirió conversión a anestesia general. Conclusión: La dexmetomidina es una buena alternativa para proporcionar sedación en los pacientes llevados a cirugía de Mohs bajo anestesia loco-regional, debido a su baja incidencia de bradicardia con repercusión hemodinámica y ausencia de la necesidad de soporte ventilatorio.

Abstract Introduction: Mohs micrographic surgery is used for the excision of malignant skin tumors and often is followed by reconstruction, prolonging the procedure, causing anxiety and discomfort to the patient. Mohs surgery is performed with local anesthesia and complementary sedation. Among the intravenous anesthetics, Dexmedetomidine is an excellent option; however, there have been reports of severe bradycardia associated with hemodynamic instability and risk of complications with its use. Objective: To describe the frequency of bradycardia with hemodynamic repercussion in patients undergoing Mohs micrographic surgery plus reconstruction, under loco regional anesthesia and Dexmedetomidine sedation. Methods: A retrospective, descriptive, observational study of 30 patients undergoing Mohs surgery between November 1, 2012 and November 30, 2013. Results: 53.3% were women, the average age was 68.4 years, 21.4% were classified as ASA I, 53.5% ASA II and 25% ASA III. The average surgical time was 184 ± 61 minutes and anesthesia with dexmedetomidine was 196 ± 65.2 minutes. Only one patient required atropine during surgery and no patient required conversion to general anesthesia. Conclusion: Dexmetomidine is an appropriate alternative to provide sedation in patients undergoing Mohs surgery under loco-regional anesthesia, due to its low incidence of bradycardia with hemodynamic repercussion and absence of the need for ventilatory support.

Slow moving neural source in the epileptic hippocampus can mimic progression of human seizures.

Fast and slow neural waves have been observed to propagate in the human brain during seizures. Yet the nature of these waves is difficult to study in a surgical setting. Here, we report an observation of two different traveling waves propagating in the in-vitro epileptic hippocampus at speeds similar to those in the human brain. A fast traveling spike and a slow moving wave were recorded simultaneously with a genetically encoded voltage sensitive fluorescent protein (VSFP Butterfly 1.2) and a high speed camera. The results of this study indicate that the fast traveling spike is NMDA-sensitive but the slow moving wave is not. Image analysis and model simulation demonstrate that the slow moving wave is moving slowly, generating the fast traveling spike and is, therefore, a moving source of the epileptiform activity. This slow moving wave is associated with a propagating neural calcium wave detected with calcium dye (OGB-1) but is independent of NMDA receptors, not related to ATP release, and much faster than those previously recorded potassium waves. Computer modeling suggests that the slow moving wave can propagate by the ephaptic effect like epileptiform activity. These findings provide an alternative explanation for slow propagation seizure wavefronts associated with fast propagating spikes.

Propagating Neural Source Revealed by Doppler Shift of Population Spiking Frequency.

Electrical activity in the brain during normal and abnormal function is associated with propagating waves of various speeds and directions. It is unclear how both fast and slow traveling waves with sometime opposite directions can coexist in the same neural tissue. By recording population spikes simultaneously throughout the unfolded rodent hippocampus with a penetrating microelectrode array, we have shown that fast and slow waves are causally related, so a slowly moving neural source generates fast-propagating waves at ∼0.12 m/s. The source of the fast population spikes is limited in space and moving at ∼0.016 m/s based on both direct and Doppler measurements among 36 different spiking trains among eight different hippocampi. The fact that the source is itself moving can account for the surprising direction reversal of the wave. Therefore, these results indicate that a small neural focus can move and that this phenomenon could explain the apparent wave reflection at tissue edges or multiple foci observed at different locations in neural tissue. SIGNIFICANCE STATEMENT: The use of novel techniques with an unfolded hippocampus and penetrating microelectrode array to record and analyze neural activity has revealed the existence of a source of neural signals that propagates throughout the hippocampus. The source itself is electrically silent, but its location can be inferred by building isochrone maps of population spikes that the source generates. The movement of the source can also be tracked by observing the Doppler frequency shift of these spikes. These results have general implications for how neural signals are generated and propagated in the hippocampus; moreover, they have important implications for the understanding of seizure generation and foci localization.

Comparación de los Perfiles Farmacodinámicos de Tres Moléculas de Remifentanilo en cuanto a su Respuesta Hemodinámica a las Maniobras de Laringoscopia e Intubación Traqueal / Comparison of the pharmacodynamic profiles of three molecules of remifentanil in terms of hemodynamic response to laryngoscopy and tracheal intubation maneuvers

Introduction: Several remifentanil products are commercialized in Colombia though they have never been compared in a clinical setting. Objective: The aim of this study was to investigate the pharmacodynamic profile of the branded remifentanil molecule (group O: Glaxo SmithKline Manufacturing S.P.A.) and two unbranded molecules (group A: Laboratorios Chalver de Colombia S.A. and group B: Instituto Biológico Contemporáneo, Argentina) registered in Colombia. Methods: We carried out a double-blind, randomized, controlled trial. The branded molecule of remifentanil (group O, n = 29) was compared with the two unbranded molecules (group A, n = 29; group B, n = 32) during anesthetic induction and tracheal intubation in adult patients ASA I without predictors for difficult airway. The target controlled infusion (TCI) doses evaluated were 6, 8 and 10ng/ml with the Minto model. Induction was complemented with propofol 5 mcg/ml (TCI) with the Schneider model and rocuronium 0.6 mg/kg. The primary outcome was the difference between preintubation (TCI equilirium) and postintubation (maximum measurement within 5 min) mean arterial pressure and heart rate. Results: A similar pharmacodynamic profile was observed in all of the studied remifentanil molecules. The differences in the change in heart rate were 1.27 (95% CI -3.11;5.67) with molecule A and 1.40 (95% CI -2.65;5.46) with molecule B compared to molecule O (beats/min). The differences in the change in mean arterial pressure were 1 (95% CI -4.81;6.81) with molecule A and 1.82 (95% CI -4.08;7.74) with molecule B compared to molecule O (mmHg). There was one case of arterial hypotension in each group. Conclusion: The results suggest that, from a pharmacodynamic point of view, branded and unbranded remifentanil molecules are similar for laryngoscopy/intubation with TCI doses 6, 8 and 10ng/ml.

Introducción: En Colombia se comercializan diferentes moléculas de Remifentanil que nunca han sido comparadas en un entorno clínico. Objetivo: El objetivo de este estudio fue investigar el perfil farmacodinámico de la molécula innovadora de Remifentanil (grupo O: Glaxo SmithKline Manufacturing S.P.A.) y dos moléculas genéricas (grupo A: Laboratorios Chalver de Colombia S.A. y grupo B: Instituto Biológico Contemporáneo, Argentina) registradas en Colombia. Métodos: Se llevó a cabo un experimento clínico doble ciego, aleatorizado, controlado. Se comparó la molécula original de Remifentanil (grupo O, n = 29) frente a las dos moléculas genéricas (grupo A, n = 29; grupo B, n = 32) durante la inducción anestésica e intubación oro-traqueal de pacientes adultos ASA I sin predictores de vía aérea difícil. Se evaluaron las dosis 6, 8 y 10 ng/ml (TCI, Target Controlled Infusion) con el modelo de Minto. La inducción se complementó con Propofol 5 mcg/ml (TCI) con modelo de Schneider y Rocuronio 0.6mg/kg. El desenlace primario se evaluó como las diferencias en la presión arterial media y en la frecuencia cardiaca preintubación (momento en que se alcanza la concentración objetivo en sitio efecto) y posintubación (máximo valor alcanzado en 5 minutos). Resultados: Se observó similitud en el perfil farmacodinámico de las moléculas de Remifentanil estudiadas. Las diferencias en el cambio de frecuencia cardiaca fue de 1.27 (IC 95% -3.11;5.67) con la molécula A y 1.40 (IC 95% -2.65;5.46) con la molécula B frente a la molécula O (latidos/minuto). Las diferencias en el cambio de presión arterial media fue de 1 (CI 95% -4.81;6.81) para la molécula A y 1.82 (IC 95% -4.08;7.74) para la molécula B frente a la molécula O (mmHg). Hubo un caso de hipotensión arterial en cada grupo. Conclusión: Los resultados sugieren que desde un punto de vista farmacodinámico las moléculas innovadora y genéricas de Remifentanil son similares para la laringo-scopia/intubación con dosis TCI de 6, 8 y 10 ng/ml.

Seizure reduction through interneuron-mediated entrainment using low frequency optical stimulation.

Low frequency electrical stimulation (LFS) can reduce neural excitability and suppress seizures in animals and patients with epilepsy. However the therapeutic outcome could benefit from the determination of the cell types involved in seizure suppression. We used optogenetic techniques to investigate the role of interneurons in LFS (1Hz) in the epileptogenic hippocampus. Optical low frequency stimulation (oLFS) was first used to activate the cation channel channelrhodopsin-2 (ChR2) in the Thy1-ChR2 transgenic mouse that expresses ChR2 in both excitatory and inhibitory neurons. We found that oLFS could effectively reduce epileptiform activity in the hippocampus through the activation of GAD-expressing hippocampal interneurons. This was confirmed using the VGAT-ChR2 transgenic mouse, allowing for selective optical activation of only GABA interneurons. Activating hippocampal interneurons through oLFS was found to cause entrainment of neural activity similar to electrical stimulation, but through a GABAA-mediated mechanism. These results confirm the robustness of the LFS paradigm and indicate that GABA interneurons play an unexpected role of shaping inter-ictal activity to decrease neural excitability in the hippocampus.

Neural activity propagation in an unfolded hippocampal preparation with a penetrating micro-electrode array.

This protocol describes a method for preparing a new in vitro flat hippocampus preparation combined with a micro-machined array to map neural activity in the hippocampus. The transverse hippocampal slice preparation is the most common tissue preparation to study hippocampus electrophysiology. A longitudinal hippocampal slice was also developed in order to investigate longitudinal connections in the hippocampus. The intact mouse hippocampus can also be maintained in vitro because its thickness allows adequate oxygen diffusion. However, these three preparations do not provide direct access to neural propagation since some of the tissue is either missing or folded. The unfolded intact hippocampus provides both transverse and longitudinal connections in a flat configuration for direct access to the tissue to analyze the full extent of signal propagation in the hippocampus in vitro. In order to effectively monitor the neural activity from the cell layer, a custom made penetrating micro-electrode array (PMEA) was fabricated and applied to the unfolded hippocampus. The PMEA with 64 electrodes of 200 µm in height could record neural activity deep inside the mouse hippocampus. The unique combination of an unfolded hippocampal preparation and the PMEA provides a new in-vitro tool to study the speed and direction of propagation of neural activity in the two-dimensional CA1-CA3 regions of the hippocampus with a high signal to noise ratio.

Un resumen de la investigación en tromboelastografía / An overview of thrombelastography research

Introducción: La tromboelastografía (TEG) es un método para valorar las características de la formación y destrucción del coágulo. Una variedad de aplicaciones han sido sugeridas en la literatura. Objetivo: Proporcionar un resumen acerca del conocimiento actual de las aplicaciones de la TEG. Métodos: Se realizó una búsqueda en la base de datos PubMed hasta julio de 2012 con el término «Thrombelastography [MeSH Terms]¼. Se analizaron artículos de estudios retrospectivos y prospectivos, revisiones y guías conteniendo información acerca de las aplicaciones de la TEG escritos en inglés y español. Resultados: La búsqueda arrojó 3.139 artículos desde 1962. Se clasificaron en 8 categorías: 862 (27,6%) asociados a enfermedades no quirúrgicas, 294 (9,4%) a trasplante hepático, 711 (22,6%) a investigación básica, 174 (5,5%) a obstetricia, 228 (7,3%) a cirugía cardiovascular, 177 (5,6%) a otras cirugías, 234 (7,4%) a técnicas anestésicas y 459 (14,6%) a fármacos. Conclusión: La TEG como herramienta diagnóstica y para guiar terapia transfusional está en aumento. La TEG aún continúa en estudio en diferentes áreas del conocimiento clínico y aún falta definir adecuadamente los alcances de esta técnica diagnóstica. Es evidente que se debe hacer un uso racional de la TEG, conocer a fondo sus fortalezas y debilidades y continuar explorando nuevas aplicaciones.

Introduction: Thrombelastography (TEG) is a method to assess clot formation and destruction. Various applications have been suggested in the literature. Objective: To provide an overview of the current knowledge about TEG applications. Methods: Adatabase search in PubMed was performed up to July 2012 using the term "Thrombelastography [MeSH Terms]". We analysed retrospective and prospective studies, reviews and guidelines with information about the applications of TEG written in English and Spanish. Results: The search resulted in 3139 papers since 1962. These were classified in 8 categories: 862 (27.6%) in non-surgical diseases, 294 (9.4%) in liver transplant, 711 (22.6%) in basic research, 174 (5.5%) in obstetrics, 228 (7.3%) in cardiovascular surgery, 177 (5.6%) in other types of surgery, 234 (7.4%) in anaesthetic techniques, and 459 (14.6%) in relation with medications. Conclusion: The application of TEG as a diagnostic tool and as a guide in transfusion therapy is increasing. Its use is still in development in different clinical fields and the advantages and limitations of this technique still have to be defined. It is evident that thrombelastography should be used with caution, and its strengths and weaknesses as well as new applications must continue to be explored.

Seizure suppression by high frequency optogenetic stimulation using in vitro and in vivo animal models of epilepsy.

BACKGROUND: Electrical high frequency stimulation (HFS) has been shown to suppress seizures. However, the mechanisms of seizure suppression remain unclear and techniques for blocking specific neuronal populations are required. OBJECTIVE: The goal is to study the optical HFS protocol on seizures as well as the underlying mechanisms relevant to the HFS-mediated seizure suppression by using optogenetic methodology. METHODS: Thy1-ChR2 transgenic mice were used in both vivo and in vitro experiments. Optical stimulation with pulse trains at 20 and 50 Hz was applied on the focus to determine its effects on in vivo seizure activity induced by 4-AP and recorded in the bilateral and ipsilateral-temporal hippocampal CA3 regions. In vitro methodology was then used to study the mechanisms of the in vivo suppression. RESULTS: Optical HFS was able to generate 82.4% seizure suppression at 50 Hz with light power of 6.1 mW and 80.2% seizure suppression at 20 Hz with light power of 2.0 mW. The suppression percentage increased by increasing the light power and saturated when the power reached above-mentioned values. In vitro experimental results indicate that seizure suppression was mediated by activation of GABA receptors. Seizure suppression effect decreased with continued application but the suppression effect could be restored by intermittent stimulation. CONCLUSIONS: This study shows that optical stimulation at high frequency targeting an excitatory opsin has potential therapeutic application for fast control of an epileptic focus. Furthermore, electrophysiological observations of extracellular and intracellular signals revealed that GABAergic neurotransmission activated by optical stimulation was responsible for the suppression.

Propagation of epileptiform activity can be independent of synaptic transmission, gap junctions, or diffusion and is consistent with electrical field transmission.

The propagation of activity in neural tissue is generally associated with synaptic transmission, but epileptiform activity in the hippocampus can propagate with or without synaptic transmission at a speed of ∼0.1 m/s. This suggests an underlying common nonsynaptic mechanism for propagation. To study this mechanism, we developed a novel unfolded hippocampus preparation, from CD1 mice of either sex, which preserves the transverse and longitudinal connections and recorded activity with a penetrating microelectrode array. Experiments using synaptic transmission and gap junction blockers indicated that longitudinal propagation is independent of chemical or electrical synaptic transmission. Propagation speeds of 0.1 m/s are not compatible with ionic diffusion or pure axonal conduction. The only other means of communication between neurons is through electric fields. Computer simulations revealed that activity can indeed propagate from cell to cell solely through field effects. These results point to an unexpected propagation mechanism for neural activity in the hippocampus involving endogenous field effect transmission.

TRPV1 antagonist capsazepine suppresses 4-AP-induced epileptiform activity in vitro and electrographic seizures in vivo.

Transient receptor potential vanilloid 1 (TRPV1) is a cation-permeable ion channel found in the peripheral and central nervous systems. The membrane surface expression of TRPV1 is known to occur in neuronal cell bodies and sensory neuron axons. TRPV1 receptors are also expressed in the hippocampus, the main epileptogenic region in the brain. Although, previous studies implicate TRPV1 channels in the generation of epilepsy, suppression of ongoing seizures by TRPV1 antagonists has not yet been attempted. Here, we evaluate the role of TRPV1 channels in the modulation of epileptiform activity as well as the anti-convulsant properties of capsazepine (CZP), an established TRPV1 competitive antagonist, using in vitro and in vivo models. To this end, we used 4-aminopyridine (4-AP) to trigger seizure-like activity. We found that CZP suppressed 4-AP induced epileptiform activity in vitro (10-100µM) and in vivo (50mg/kg s.c.). In contrast, capsaicin enhanced 4-AP induced epileptiform activity in vitro (1-100µM) and triggered bursting activity in vivo (100µM dialysis perfusion), which was abolished by the TRPV1 antagonist CZP. To further investigate the mechanisms of TRPV1 modulation, we studied the effect of capsaicin and CZP on evoked potentials. Capsaicin (1-100µM) and CZP (10-100µM) increased and decreased, respectively, the amplitude of extracellular field evoked potentials in a concentration-dependent manner. Additional in vitro studies showed that the effect of the TRPV1 blocker on evoked potentials was similar whether the response was orthodromic or antidromic, suggesting that the effect involves interference with membrane depolarization on cell bodies and axons. The fact that CZP could act directly on axons was confirmed by decreased amplitude of the compound action potential and by an increased delay of both the antidromic potentials and the axonal response. Histological studies using transgenic mice also show that, in addition to the known neural expression, TRPV1 channels are widely expressed in alvear oligodendrocytes in the hippocampus. Taken together, these results indicate that activation of TRPV1 channels leads to enhanced excitability, while their inhibition can effectively suppress ongoing electrographic seizures. These results support a role for TRPV1 channels in the suppression of convulsive activity, indicating that antagonism of TRPV1 channels particularly in axons may possibly be a novel target for effective acute suppression of seizures.

Remifentanilo versus propofol con infusión controlada a objetivo en sitio efecto para la sedación de pacientes durante procedimientos endoscópicos gastrointestinales: ensayo clínico controlado aleatorizado / Remifentanil vs. propofol controlled infusion for sedation of patients undergoing gastrointestinal endoscopic procedures: A clinical randomized controlled clinical trial

Contexto: La administración de sedación con sistemas de infusión controlada a objetivo (TCI) podría ofrecer una alternativa segura para el manejo del malestar de los pacientes llevados a procedimientos endoscópicos gastrointestinales. Sin embargo, no se conoce qué medicamento de los disponibles para TCI es el más apropiado. El objetivo del estudio fue comparar remifentanilo y propofol en TCI para la sedación de pacientes durante procedimientos endoscópicos gastrointestinales. Materiales y métodos: Sesenta y nueve pacientes que requerían un procedimiento endos-cópico gastrointestinal fueron asignados aleatoriamente a recibir una TCI en sitio efecto (TCIe) de remifentanilo (n = 30) o propofol (n = 39). El desenlace primario fue la satisfacción del paciente. Los desenlaces secundarios incluyeron la satisfacción del gastroenterólogo, se compararon las proporciones de eventos adversos entre los 2 grupos (ocurrencia de arritmias cardiacas, depresión respiratoria leve, depresión respiratoria mayor, bradicardia, hipotensión, dolor, náuseas o vómitos, y ausencia de amnesia) y el nivel de consciencia. Número de registro retrospectivo: NCT01746641. Resultados: Las medianas (rango) de satisfacción del paciente entre remifentanilo y propofol fueron 1 (1-2) y 2 (1-4), respectivamente (Chi², p< 0,001). Se encontraron diferencias en la ocurrencia de dolor durante el procedimiento (mediana 2 vs. 1, Chi², p = 0,042), náuseas o vómito (4 vs. 0, Chi², p = 0,01), y ausencia de amnesia (29 vs. 10, Chi², p<0,001) entre remifentanilo y propofol, respectivamente. Para las otras variables estudiadas no se encontraron diferencias estadísticamente significativas entre los grupos. Conclusión: El propofol en TCIe parece ser un medicamento adecuado para la sedación de pacientes durante procedimientos endoscópicos gastrointestinales, y presentó menores efectos adversos y mayor satisfacción del paciente. Es probable que con la sinergia de estos 2 medicamentos se pudiera lograr disminuir aún más los efectos adversos.

Background: Target controlled infusion (TCI) for the administration of anesthesia may provide a safe alternative for managing the discomfort of patients undergoing gastrointestinal endoscopic procedures. However, the most appropriate drug available for TCI is yet to be established. The objective of this trial was to comparemifentanil vs. propofol in TCI for sedating patients during GI endoscopy. Materials and methods: Sixty-nine patients requiring GI endoscopies were randomly distributed to receive remifentanil (n = 30) or propofol (n = 39) TCI at the effect site (e). The primary outcome was patient’s satisfaction. Secondary outcomes included the gastroenterologist satisfaction, comparison of the percentage of adverse events between the two groups (occurrence of arrhythmias, major respiratory depression, bradycardia, hypotension, pain, nausea or vomiting and absence of amnesia), and the level of awareness. Retrospective registration number is NCT01746641 at Clinicaltrials.gov. Results: The mean (range) of patient satisfaction with remifentanil vs propofol was 1 (1-2) and 2 (1-4), respectively ([1]2, p < 0,001). Pain during the procedurewas found to differ between remifentanil and propofol (mean 2 vs. 1, [1]2, p = 0,042), nausea or vomiting (4 vs. 0, [1]2, p = 0,01), and absence of amnesia (29 vs. 10, [1]2, p < 0,001), respectively. No statistically significant differences were found between the two groups. Conclusion: Propofol in TCI seems to be an adequate agent for sedation of patients undergoing GI endoscopic procedures, with less adverse effects and higher patient satisfaction. Most likely, the combination of these two drugs may be synergistic and further reduce any adverse effects.

Sonic hedgehog maintains cellular and neurochemical homeostasis in the adult nigrostriatal circuit.

Non cell-autonomous processes are thought to play critical roles in the cellular maintenance of the healthy and diseased brain but mechanistic details remain unclear. We report that the interruption of a non cell-autonomous mode of sonic hedgehog (Shh) signaling originating from dopaminergic neurons causes progressive, adult-onset degeneration of dopaminergic, cholinergic, and fast spiking GABAergic neurons of the mesostriatal circuit, imbalance of cholinergic and dopaminergic neurotransmission, and motor deficits reminiscent of Parkinson's disease. Variable Shh signaling results in graded inhibition of muscarinic autoreceptor- and glial cell line-derived neurotrophic factor (GDNF)-expression in the striatum. Reciprocally, graded signals that emanate from striatal cholinergic neurons and engage the canonical GDNF receptor Ret inhibit Shh expression in dopaminergic neurons. Thus, we discovered a mechanism for neuronal subtype specific and reciprocal communication that is essential for neurochemical and structural homeostasis in the nigrostriatal circuit. These results provide integrative insights into non cell-autonomous processes likely at play in neurodegenerative conditions such as Parkinson's disease.

Sequential depletion of rat testicular lipids with long-chain and very long-chain polyenoic fatty acids after X-ray-induced interruption of spermatogenesis.

When a single dose of X-rays is applied to the adult rat testis, stem spermatogonia are damaged, and spermatogenesis is interrupted. Supported by Sertoli cells, spermatogenic cells that endure irradiation complete their differentiation and gradually leave the testis as spermatozoa. In this study, the in vivo changes taking place a number of weeks after irradiation revealed cell-specific features of testicular lipid classes. A linear drop, taking about six weeks, in testis weight, nonlipid materials, free cholesterol, and 22:5n-6-rich glycerophospholipids took place with germ cell depletion. Sphingomyelins and ceramides with nonhydroxy very long-chain polyenoic fatty acids (n-VLCPUFA) disappeared in four weeks, together with the last spermatocytes, whereas species with 2-hydroxy VLCPUFA lasted for six weeks, disappearing with the last spermatids and spermatozoa. The amount per testis of 22:5n-6-rich triacylglycerols, unchanged for four weeks, fell between weeks 4 and 6, associating these lipids with spermatids and their residual bodies, detected as small, bright lipid droplets. In contrast, 22:5n-6-rich species of cholesterol esters and large lipid droplets increased in seminiferous tubules up to week 6, revealing they are Sertoli cell products. At week 30, the lipid and fatty acid profiles reflected the resulting permanent testicular involution. Our data highlight the importance of Sertoli cells in maintaining lipid homeostasis during normal spermatogenesis.

Imaging diagnosis--Medullary tibial infarction in a horse.

An Andalusian Stallion with left hind limb lameness had a radiolucent lesion in the medullary cavity of distal tibial metaphysis. After euthanasia for other disease, the tibia was examined with magnetic resonance (MR). The MR imaging sequences were characterized by a double line sign, although showing quite different lesion area intensities. Histologically, the lesion was compatible with medullary infarction being characterized by normal spongy bone, areas of abundant fibrous tissue and numerous necrotic adipocytes in various stages of destruction.

Nephrotoxicosis in Iberian piglets subsequent to exposure to melamine and derivatives in Spain between 2003 and 2006.

Between November 2003 and September 2006, 300 to 400 45-60-day-old Iberian piglets developed anorexia, polydipsia, and lethargy. Piglets were from 5 different farms in the western part of Spain. Morbidity was between 40% and 60%, and mortality ranged from 20% to 40% of the total population of postweaning piglets. In the 9 piglets in which postmortem examinations were conducted, kidneys were enlarged with yellow foci in the cortex and medulla. Microscopically, these foci were accumulations of crystals within the lumina of dilated distal tubules and collecting ducts, causing flattening of the renal tubular epithelial cells. The crystals displayed a multicolored birefringence under cross-polarized light. The multinucleated giant cells surrounding the crystals, interstitial fibrosis, and nonsuppurative infiltrates indicated a chronic inflammatory response. Toxicologic analysis of fixed kidney tissues from 4 piglets demonstrated the presence of melamine, ammeline, ammelide, and cyanuric acid. Ammelide concentrations were highest, ranging from 39,000 to 92,000 mg/kg, followed by ammeline (20,000-34,000 mg/kg), melamine (9,200-29,000 mg/kg), and cyanuric acid (2,200-9,100 mg/kg). The clinical, histologic, and toxicologic findings in affected piglets were similar to those reported in dogs and cats that died of melamine and melamine analogue-associated renal failure in 2004 and 2007. To the authors' knowledge, this is the first documented report of poisoning due to melamine and its analogues in pigs and demonstrates that contamination of pig feed occurred as early as 2003.

Comparison of three immunological diagnostic tests for the detection of avian tuberculosis in naturally infected red deer (Cervus elaphus).

Cases of tuberculosis due to Mycobacterium avium subsp. avium in 52 adult red deer (Cervus elaphus) from a farm were studied using different diagnostic techniques. Immunological probes consisted of the comparative cervical tuberculin (CCT) skin test, the interferon-gamma (IFN-gamma) assay, and 2 enzyme-linked immunosorbent assays (ELISAs) employing either avian purified protein derivatives or protoplasmatic antigen (PPA-3) as antigens. Three of the animals were euthanized due to severe weakness, loss of weight, and emaciation. Macroscopically, the 3 animals showed tuberculous lesions located mainly in lymph nodes of the digestive system and small intestine but also in other organs and lymph nodes. Polymerase chain reaction was carried out on samples from the 3 deer using primers to detect IS901, IS900, and IS6110, specific for Mycobacterium avium subsp. avium, Mycobacterium avium subsp. paratuberculosis, and Mycobacterium tuberculosis complex, including Mycobacterium bovis, respectively. The last 2 agents cause pathologies very similar to avian tuberculosis in deer. The 3 deer were strongly positive by both ELISAs, slightly positive by the IFN-gamma test, and 1 of 2 was positive by the CCT test. As with domestic ruminants, ELISA could detect deer in an advanced stage of infection, with large numbers of mycobacteria.