Mechanism of dexmedetomidine preconditioning on spinal cord analgesia in rats with functional chronic visceral pain

Purpose: To analyze the effect and mechanism of dexmedetomidine (DEX) analgesia pretreatment on functional chronic visceral pain in rats. Methods: Rats were divided into six groups: W1, W2, W3, W4, W5, and W6. The behavioral changes and electrophysiological indexes of rats in each group before and after DEX treatment were detected. Results: The levels of abdominal withdrawal reflex (AWR) in W5 and W6 groups were significantly lower than those in group W3, while the levels of thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were significantly higher than those in group W3 (p < 0.05). The electromyographic signals of W1, W5, and W6 groups showed little fluctuation, while those of groups W2, W3, and W4 showed obvious fluctuation. TLR4 mRNA expression, IRF3, P65, and phosphorylation levels in W4, W5, and W6 groups were significantly lower than those in group W2 (p < 0.05). Conclusions: Dexmedetomidine epidural anesthesia pretreatment could significantly inhibit visceral pain response in rats with functional chronic visceral pain, and its mechanism was related to the activation of TLR4 in spinal dorsal horn tissue of rats and the activation inhibition of IRF3 and P65 in the downstream key signals.

Forward masking with frequency-following response analyses

ABSTRACT Purpose: to analyze forward masking in normally hearing young people, by using frequency-following responses. Methods: the synthetic syllable /da/ was used for the recordings of ten individuals, in the following conditions: /da/ with no masking, and /da/ after 4, 16, 32, and 64 milliseconds of masking. F-test (ANOVA) was applied for repeated measures with the Greenhouse-Geisser correction to compare testing conditions. For significant differences, multiple comparisons (between pairs of conditions) and Bonferroni correction were used. Data normality was verified by applying the Shapiro-Wilk test, and statistical significance was used at 5%. Results: wave latencies of all masking conditions were compared with those of no masking. A latency delay was observed in the transient region of the response (PV and A) in all masking conditions, except for 64 milliseconds. Latency delay also occurred for waves PW, PX, and PY, which corresponded to the sustained region of the response. Conclusion: forward masking was observed, by using frequency-following responses with /da/ syllable in four intervals (4, 16, 32, and 64 ms) of preceding masking. Forward masking was more evident in the transient region of the response than in the sustained one. This study highlights the importance of electrophysiological testing in temporal processing assessment.

The prognostic value of demyelinating electrophysiologic findings and cerebrospinal fluid protein levels in acute inflammatory demyelinating polyneuropathy / O valor prognóstico dos achados eletrofisiológicos desmielinizantes e os níveis de proteína do líquido cefalorraquidiano na polineuropatia desmielinizante inflamatória aguda

ABSTRACT Background: Guillain-Barre syndrome is an acute immune-mediated polyneuropathy characterized by rapidly evolving symptoms and disability. Cerebrospinal fluid analysis and electrophysiological studies are crucial in the diagnosis of this syndrome. Objective: To evaluate the prognostic value of the type and number of demyelinating findings and cerebrospinal fluid protein levels in patients with acute inflammatory demyelinating polyneuropathy. Methods: We retrospectively analyzed electrophysiological data and cerebrospinal fluid of 67 consecutive patients with acute inflammatory demyelinating polyneuropathy from Istanbul, Turkey (2011-2019) studied ≤ 24 hours post-onset. Results: The patients who met a higher number of demyelinating criteria had increased disability scores in the first day and first month, and higher cerebrospinal fluid protein levels were correlated with worse prognosis both on the first day and the first month. However, the disability scores did not correlate with any single specific criterion, and no significant correlation was found between the number of satisfied criteria and cerebrospinal fluid protein levels. Conclusions: The number of demyelinating criteria that are met and high cerebrospinal fluid protein levels at the disease onset may be valuable prognostic markers. More systematic studies conducted with serial nerve conduction studies are required to highlight the roles of the suggested criteria in clinical practice.

RESUMO Introdução: A síndrome de Guillain-Barré é uma polineuropatia imunomediada aguda caracterizada por sintomas e incapacidade em rápida evolução. A análise do líquido cefalorraquidiano e os estudos eletrofisiológicos são cruciais no diagnóstico dessa síndrome. Objetivo: Avaliar o valor prognóstico do tipo e número de achados desmielinizantes e dos níveis de proteínas do líquido cefalorraquidiano em pacientes com polineuropatia desmielinizante inflamatória aguda. Métodos: Analisamos retrospectivamente dados eletrofisiológicos e líquido cefalorraquidiano de 67 pacientes consecutivos com polineuropatia desmielinizante inflamatória aguda de Istambul, Turquia (2011-2019), estudados ≤24 horas após o início. Resultados: Os pacientes que atenderam a um número maior de critérios desmielinizantes apresentaram escores de incapacidade aumentados no primeiro dia e no primeiro mês, e níveis mais altos de proteína do líquido cefalorraquidiano foram correlacionados com pior prognóstico no primeiro dia e no primeiro mês. No entanto, os escores de incapacidade não se correlacionaram com nenhum critério específico e não foi encontrada correlação significativa entre o número de critérios satisfeitos e os níveis de proteína do líquido cefalorraquidiano. Conclusões: O número de critérios desmielinizantes atendidos e altos níveis de proteína no líquido cefalorraquidiano no início da doença podem ser marcadores prognósticos valiosos. Estudos mais sistemáticos conduzidos com estudos de condução nervosa em série são necessários para destacar os papéis dos critérios sugeridos na prática clínica.

Evaluation of Electrocardiographic Ventricular Depolarization and Repolarization Variables in Type 1 Diabetes Mellitus / Avaliação de Variáveis Eletrocardiográficas de Despolarização e Repolarização Ventricular em Diabetes Mellitus Tipo 1

Abstract Background: The risk of cardiovascular events and sudden death increases with type 1 diabetes mellitus (T1DM). Objective: To evaluate electrocardiographic markers of arrhythmias in T1DM patients. Methods: Electrocardiographic parameters reflecting ventricular depolarization and repolarization, namely, QT, QTc, QTd, QTdc, Tp-e, JT, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios, of 46 patients diagnosed with T1DM were retrospectively analyzed and compared with 46 healthy age-, sex-, and body mass-matched controls. Correlations between T1DM duration, hemoglobin A1c (HbA1c), and ventricular repolarization variables were analyzed. P values lower than 0.05 were considered statistically significant. Results: Diabetes duration was 16.6 ± 7.1 years, and HbA1c was 10.81% ± 3.27% in the T1DM group. In comparison with the control group, heart rate, QTc, QTd, QTdc, Tp-e and JTc intervals, Tp-e/QT ratio (p < 0.001), and Tp-e/QTc ratio (p = 0.007) were significantly higher in T1DM patients. T1DM duration and HbA1c levels were significantly correlated with QTc, QTd, QTdc, Tp-e, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios. Conclusions: In T1DM patients, potential electrocardiographic repolarization predictors were significantly increased in correlation with disease duration and HbA1c levels. These findings may contribute to the understanding of sudden cardiac death in patients with T1DM.

Resumo Fundamento: O risco de eventos cardiovasculares e morte súbita aumenta com diabetes mellitus tipo 1 (DM1). Objetivo: Avaliar alguns marcadores eletrocardiográficos de arritmias em pacientes com DM1. Métodos: Parâmetros eletrocardiográficos que refletem despolarização e repolarização ventricular, a saber, os intervalos QT, QTc, QTd, QTdc, Tp-e, JT e JTc e as relações Tp-e/QT e Tp-e/QTc, de 46 pacientes diagnosticados com DM1 foram retrospectivamente analisados e comparados com 46 controles saudáveis, pareados por idade, sexo e massa corporal. As correlações entre duração de DM1, HbA1c e variáveis de repolarização ventricular foram analisadas. Foram considerados estatisticamente significativos os valores de p inferiores a 0,05. Resultados: A duração de diabetes foi de 16,6 ± 7,1 anos, e HbA1c foi 10,81% ± 3,27% no grupo DM1. Em comparação com o grupo controle, a frequência cardíaca, os intervalos QTc, QTd, QTdc, Tp-e e JTc, a relação Tp-e/QT (p < 0,001) e a relação Tp-e/QTc (p = 0,007) foram significativamente mais altos em pacientes com DM1. A duração de DM1 e os níveis de HbA1c foram significativamente correlacionados com os intervalos QTc, QTd, QTdc, Tp-e e JTc e com as relações Tp-e/QT e Tp-e/QTc. Conclusões: Em pacientes com DM1, potenciais preditores eletrocardiográficos de repolarização foram significativamente aumentados em correlação com a duração da doença e com os níveis de HbA1c. Estes achados podem contribuir à compreensão da morte súbita cardíaca em pacientes com DM1.

Influência do sexo nas respostas do potencial evocado auditivo de tronco encefálico com diferentes estímulos em neonatos / The influence of gender on brainstem auditory evoked potentials responses to different stimuli in newborns

RESUMO Objetivo avaliar a influência da variável sexo nos valores da latência e amplitude da onda V do potencial evocado auditivo de tronco encefálico, com diferentes estímulos em neonatos. Métodos participaram deste estudo 62 neonatos nascidos a termo (29 do sexo feminino e 33 do sexo masculino). Realizou-se a pesquisa de limiar eletrofisiológico do potencial evocado auditivo de tronco encefálico com quatro estímulos diferentes (clique, Ichirp banda larga-BL, tone burst e Ichirp-frequência específica-FE), nas intensidades de 60, 40 e 20 dBnNA. A variável sexo foi comparada para cada estímulo e intensidade. Resultados os resultados obtidos demonstraram menor latência e maior amplitude no sexo feminino para o estímulo clique. Entretanto, para o estímulo tone burst, o sexo feminino apresentou maior latência e maior amplitude. Quando utilizados os estímulos Ichirp-BL e Ichirp-FE, a variável sexo não apresentou diferença estatisticamente significativa para os valores de latência e amplitude. Conclusão a onda V do PEATE de neonatos sofre influência da variável sexo, quando utilizados os estímulos clique e tone burst. Entretanto, não houve tal influência quando utilizado o estímulo Ichirp banda larga-BL e o estímulo Ichirp frequência específica-FE.

ABSTRACT Purpose To evaluate the influence of gender on the brainstem auditory evoked potentials V-wave latency and amplitude values in newborns, with different stimuli. Methods 62 full-term newborns (29 females and 33 males) participated in this study. The electrophysiological threshold of the brainstem auditory evoked potential was investigated with four different stimuli - click, broadband (BB) Ichirp, tone-burst, and specific-frequency (SF) Ichirp -, in intensities of 60, 40 and 20 dBnHL. The genders were compared in each stimulus and intensity. Results The results obtained showed lower latency and greater amplitude in females for the click stimulus. However, for tone-burst, the females presented higher latency and greater amplitude. When the BB-Ichirp and SF-Ichirp stimuli were used, the gender did not present a statistically significant difference in the latency and amplitude values. Conclusion The BAEP V-wave in newborns is influenced by gender when the click and tone-burst stimuli are used. However, such influence was not noted when the BB-Ichirp and SF-Ichirp stimuli were used.

Electrophysiological responses to different follicle-stimulating hormone isoforms on human cumulus oophorus cells: preliminary results / Respostas eletrofisiológicas a diferentes isoformas de FSH em células humanas do cumulus oophorus: resultados preliminares

Abstract Objective The aim of the present study was to provide a better understanding of the specific action of two follicle-stimulating hormone (FSH) isoforms (β-follitropin and sheep FSH) on the membrane potential of human cumulus cells. Methods Electrophysiological data were associated with the characteristics of the patient, such as age and cause of infertility. The membrane potential of cumulus cells was recorded with borosilicate microelectrodes filled with KCl (3 M) with tip resistance of 15 to 25 MΩ. Sheep FSH and β-follitropin were topically administered onto the cells after stabilization of the resting potential for at least 5 minutes. Results In cumulus cells, the mean resting membrane potential was - 34.02 ± 2.04 mV (n = 14). The mean membrane resistance was 16.5 ± 1.8 MΩ (n = 14). Sheep FSH (4 mUI/mL) and β-follitropin (4 mUI/mL) produced depolarization in the membrane potential 180 and 120 seconds after the administration of the hormone, respectively. Conclusion Both FSH isoforms induced similar depolarization patterns, but β-follitropin presented a faster response. A better understanding of the differences of the effects of FSH isoforms on cell membrane potential shall contribute to improve the use of gonadotrophins in fertility treatments.

Resumo Objetivo O objetivo do presente estudo foi fornecer uma melhor compreensão da ação específica de duas isoformas de hormônio folículo estimulante (FSH, sigla em inglês) (β-folitropina e FSH ovino) no potencial de membrana de células do cumulus oophorus humanas. Métodos Dados eletrofisiológicos foram associados às características da paciente, como idade e causa da infertilidade. O potencial de membrana das células do cumulus foi registrado com microeletrodos de borossilicato preenchidos com KCl (3 M) com uma resistência de 15 a 25 MΩ. O FSH ovino e a β-folitropina foram administrados topicamente nas células após a estabilização do potencial de repouso durante pelo menos 5 minutos. Resultados Nas células do cumulus, o potencial médio de membrana em repouso foi de -34,02 ± 2,04 mV (n = 14). A resistência média da membrana foi de 16,5 ± 1,8 MΩ (n = 14). O FSH ovino (4 mUI/mL) e a β-folitropina (4 mUI/mL) produziram despolarização no potencial de membrana 180 e 120 segundos após a aplicação do hormônio, respectivamente. Conclusão Ambas as isoformas de FSH induzem padrões de despolarização semelhantes, mas a β-folitropina apresentou uma resposta mais rápida. Uma melhor compreensão das diferenças dos efeitos das isoformas do FSH no potencial da membrana celular contribuirá para aprimorar o uso das gonadotrofinas no estímulo ovariano controlado e em protocolos de maturação oocitária in vitro.

Applicability of Evoked Auditory Brainstem Responses with Complex Stimuli in Adults with Hearing Loss

Abstract Introduction The use of the speech-evoked auditory brainstem response (ABR) shows how the brainstem operates up to the subcortex in a more complexmanner than when the click-evoked ABR is used. Objective To study the applicability of the speech-evoked ABR in adults with hearing loss. Methods The sample was composed of a study group of 11 subjects, with ages ranging between 18 and 59 years, and auditory thresholds within normal standards, with loss of up to 65 dB at high frequencies or up to moderately severe symmetric sensorineural hearing loss. The sample underwent a basic audiological assessment, as well as speech-evoked ABR and click-evoked ABR, in which waves I, III and V, and V, A, C, D, E, F were respectively marked. The electrophysiological assessments were performed using the SmartEP device (Intelligent Hearing Systems, Miami, FL, US). Results For the speech-evoked ABR, the reference values were used in the identification and analysis of the study group. Those values found for the study group were: V = 8.56; A = 10.97; C = 21.33; D = 29.51; E = 37.93; F = 46.96; and O = 55.97. In the comparison between groups, the study group presented an increase in latency only in wave C. Conclusion The speech-evoked ABR can be performed in subjects with up to moderately severe hearing loss, and the test proved to be appropriate, because, unlike the click-evoked ABR, the former does not suffer influence of peripheral hearing loss.

Amusia and its electrophysiological correlates in neurofibromatosis type 1 / Amusia e seus correlatos eletrofisiológicos na neurofibromatose tipo 1

ABSTRACT Auditory processing deficits are common in people with neurofibromatosis type 1 (NF1) and they often report difficulties in musical performance. Objective: We investigated whether NF1 could be associated with amusia as well as with some impairment of primary auditory cortex activity. Methods: Eighteen people with NF1 and 22 healthy volunteers, matched for age, sex and educational level, were evaluated with the Montreal Battery Evaluation of Amusia - short version. The integrity of cortical primary auditory processing areas was evaluated by evoked potential mismatch negativity. Results: Amusia was correlated with NF1 (p = 0.001, odds ratio = 42.0, confidence interval 4.5-39.6). Patients with NF1 exhibited a greater prevalence of amusia than healthy controls (67% vs. 4.5%) and difficulties in both melodic and temporal music perception. Worse performance on the Montreal Battery Evaluation of Amusia was correlated with a greater mismatch negativity latency in NF1 group. Conclusions: Amusia is a common feature in NF1 and may result from impairment of activity in primary auditory processing areas.

RESUMO Déficits de processamento auditivo são comuns em pessoas com neurofibromatose tipo 1 (NF1), que também se queixam frequentemente de dificuldades no desempenho musical. Objetivos: Nós investigamos se a NF1 poderia estar associada à amusia, assim como a algum comprometimento da atividade do córtex auditivo primário. Métodos: Dezoito pessoas com NF1 e 22 controles sem a doença, pareados por idade, sexo e nível educacional, foram avaliados por meio da versão reduzida da Bateria de Avaliação de Amusia de Montreal (MBEA). A integridade das áreas corticais primárias do processamento auditivo foi avaliada através do potencial evocado auditivo mismacth negativity (MMN). Resultados: A amusia correlacionou-se com a NF1 (p = 0,001, odds ratio = 42,0, intervalo de confiança 4,5-39,6). Os pacientes com NF1 apresentaram maior prevalência de amusia do que os controles saudáveis (67% vs. 4,5%) e dificuldades na percepção musical, tanto melódica quanto temporal. O desempenho pior na MBEA foi correlacionado com maiores latências do MMN no grupo NF1. Conclusões: A amusia é uma característica comum na NF1 e pode resultar do comprometimento da atividade de áreas de processamento auditivo primário.

Microscopic aspects of electrosensory system on the partially euryhaline lesser guitarfish

ABSTRACT The electrosensory system on elasmobranchs consists of subcutaneous electroreceptor organs known as ampullae of Lorenzini. The present study investigated the ampullae of Lorenzini morphology of the lesser guitarfish Zapteryx brevirostris, using light microscopy and scanning electron microscopy. The pore number found in the ventral skin surface is much higher than that found in the dorsal portion, characteristic of species that inhabit the euphotic zone. Under light microscopy it was possible to observe that the wall canal consists of a single layer of squamous epithelial cells. The canal features distal expansion, where the ampullae are located with up to six alveoli. The sensory epithelium of ampullae is composed by cubic cells, with oval nucleus, restricted to the interior of the alveoli. With analysis the clusters under scanning electron microscopy, it was possible to observe the structure and the random arrangement of individual ampullae, canals and nerves. The distribution of dorsal and ventral pores and ampullae in Z. brevirostris resembled those of the same family. The number of alveoli per ampullae was similar to that found in euryhaline elasmobranchs species, suggesting that the morphological organization in Z. brevirostris is linked to its possible evolutionary transitory position among batoids.

Lambert-Eaton myasthenic syndrome: the 60th anniversary of Eaton and Lambert's pioneering article / Síndrome miastênica de Lambert-Eaton: o 60° aniversário do artigo pioneiro de Eaton e Lambert

ABSTRACT This historical review describes the contribution of Drs. Lee M. Eaton and Edward H. Lambert to the diagnosis of myasthenic syndrome on the 60th anniversary of their pioneering article (JAMA 1957) on the disease. There are important landmarks in their article on a disorder of the neuromuscular junction associated with thoracic neoplasm and the electrophysiological criteria for Lambert-Eaton myasthenic syndrome (LEMS). After 60 years, the main electrophysiological criteria described in Eaton and Lambert's pioneering article are still currently useful in the diagnosis of LEMS.

RESUMO Essa revisão histórica enfatiza a contribuição do Dr Lee M Eaton e do Dr Edward H. Lambert para o diagnóstico da síndrome miastênica no 60o aniversário do seu artigo pioneiro (JAMA 1957) para essa doença. Existem importantes marcos no artigo de Eaton e Lambert, como uma desordem da junção neuromuscular associada à neoplasia torácica e critério diagnóstico para síndrome miastênica de Lambert-Eaton (LEMS). Após 60 anos, os principais critérios diagnósticos descritos para LEMS no artigo pioneiro de Eaton e Lambert continuam úteis no diagnóstico da LEMS.

Confiabilidad de los estudios de neuroconducción en el síndrome de túnel carpiano / Reliability of neuroconduction studies in carpal tunnel syndrome

RESUMEN Objetivo Determinar la confiabilidad entre dos observadores y el cambio mínimo detectable de los estudios de neuroconducción para diagnosticar el síndrome de túnel carpiano. Métodos Se estudiaron 69 pacientes remitidos para estudio electrofisiológico por sospecha de síndrome de túnel carpiano. A los pacientes, se les realizaron dos exámenes, dos días diferentes, por dos evaluadores. Se evaluaron las latencias sensitivas y motoras de los nervios mediano y cubital; todos fueron clasificados como negativos, incipientes, leves, moderados, severos o extremos. Se calculó la variación relativa entre ensayos, el coeficiente de correlación intraclase, el índice de kappa, el límite de acuerdo y el cambio mínimo detectable. Resultados La variación relativa entre ensayos de la latencia motora del nervio mediano fue de -6,8 % a 15,9 % con coeficiente de correlación intraclase de 0,98 para la diferencia con la latencia del nervio cubital. El cambio mínimo detectable fue de 0,4ms. La variación relativa entre ensayos de la latencia sensitiva del nervio mediano fue -5,0 % a 11 % con coeficiente de correlación intraclase de 0,95 para la diferencia con el nervio cubital. El cambio mínimo detectable fue de 0,2ms. La clasificación ele trofisiológica coincidió en 93 % de los casos, índice de kappa de 0,89. Conclusiones Las latencias sensitivas y motoras del nervio mediano así como la diferencia de estas con el nervio cubital son medidas confiables. El cambio mínimo detectable obtenido en nuestro estudio le sirve al clínico para establecer si los cambios de las latencias en estudios consecutivos o después del tratamiento son significativos.(AU)

ABSTRACT Objective To determine the reliability of neuroconduction studies by comparing two observers and detecting minimum changes when diagnosing carpal tunnel syndrome. Methods Sixty-nine patients referred for electrophysiological study due to suspected carpal tunnel syndrome were studied. The patients underwent two examinations, performed by two evaluators, on two different days. Sensory and motor latencies of the median and ulnar nerves were evaluated; all were classified as negative, incipient, mild, moderate, severe or extreme. Relative interval variation, intraclass correlation coefficient, kappa index, limit of agreement and minimum detectable change were estimated. Results The relative variation of motor nerve latency of the median nerve was -6.8% to 15.9%, with intraclass correlation coefficient of 0.98 for the difference of median-ulnar nerve latency. The minimum detected change was 0.4ms, while the relative interval variation of sensory latency of the median nerve was -5.0% to 11%, with intraclass correlation coefficient of 0.95 for difference with the ulnar nerve. The minimum detectable change was 0.2ms. Electrophysiological classification agreed in 93% of the cases, with a kappa index of 0.89. Conclusions Sensory and motor latencies of the median nerve, as well as the difference between them and the ulnar nerve, are reliable measures. The minimum detectable change obtained in our study helps clinicians to establish whether changes in latencies in consecutive or post-treatment studies are significant.(AU)

Modelo in vitro para el estudio del papel de la unión mesopontina en la generación del sueño de movimientos oculares rápidos y la vigilia / In vitro model for the study of the role of the mesopontine region in rapid eye movement (REM) sleep and wakefulness / Modelo in vitro para o estudo do papel da união mesopontina na geração de sono de movimentos oculares rápidos e da vigília

El estudio de las estrategias neurales para la organización del comportamiento en vertebrados constituye un desafío mayor para la Neurociencia. El avance del conocimiento en este campo depende de manera crítica de la utilización de modelos experimentales adecuados que admitan múltiples niveles de análisis (p.ej: comportamental, circuital, celular, sináptico, molecular) y abordajes multitécnicos. Nos propusimos analizar in vitro una red neural de la unión mesopontina del tronco encefálico críticamente implicada en el control del sueño de movimientos oculares rápidos (S-REM). Pese al cúmulo de evidencias que apoyan el papel desempeñado por esta red en relación al S-REM, los mecanismos celulares y sinápticos que subyacen a este control son poco conocidos y continúan siendo objeto de intensa investigación. Para avanzar en el conocimiento de estos mecanismos, se llevó a cabo la caracterización morfológica y funcional de una rodaja de tronco encefálico de la rata, en la que las estructuras críticas para el control del S-REM, i.e.: núcleos tegmentales laterodorsal y pedúnculopontino, y su proyección al núcleo reticular pontis oralis (PnO), están presentes y son operativas. La inclusión del núcleo motor del trigémino en la rodaja permitió detectar cambios de la excitabilidad de las motoneuronas ante manipulaciones farmacológicas del PnO, representativos de los cambios del tono muscular asociados a maniobras similares realizadas in vivo. La utilización de este modelo in vitro de S-REM, permitirá aportar a la dilucidación de las estrategias neurales que operan en niveles intermedios de organización del SN en mamíferos para la generación y regulación de un estado comportamental.

The study of the neural basis of behavior is a major challenge in Neuroscience. Advancing our knowledge in this field depends, critically, on the use of experimental paradigms that provide multiple levels of analysis, as well as powerful techniques. We have selected, as a model of a neural plan that organizes a complex behavior, a neural network located in the mesopontine junction. This region is thought to be both necessary and sufficient for the generation of rapid eye movement (REM) sleep, although the cellular and synaptic mechanisms involved in the control of this behavioral state at the mesopontine level are still under debate and remain poorly understood. As part of a long term effort to gain insight into these mechanisms, we carried out the morphological and functional characterization of a slice preparation of rat brainstem and we demonstrate that critical structures for the control of REM sleep - the laterodorsal and pedunculopontine tegmental nuclei and their projection to the oral part of the pontine reticular nucleus (PnO) - are present and are operational. The presence of the trigeminal motor nucleus in the slice sought to include in the experimental model a structure capable of expressing changes of the excitability of the motorneurons caused by pharmacological manipulations of the PnO, representative of changes of muscle tone associated with similar maneuvers performed in vivo. The use of this in vitro model of REM sleep will provide critical information to elucidate neural strategies that operate at intermediate levels of central nervous system organization in mammals to control behavioral states.

O estudo de estratégias neurais para a organização do comportamento em vertebrados constitui um desafio maior para a Neurociencia. O avanço do conhecimento nessa área depende criticamente da utilização de modelos experimentais adequados que suportem múltiplos níveis de análise (por exemplo: comportamental, circuital, celular, sináptico e molecular) e abordagens por múltiplas técnicas. Decidiu-se analisar in vitro uma rede neural da união mesopontina do tronco encefálico criticamente envolvida no controle do sono de movimentos oculares rápidos (S-REM). Apesar da riqueza de provas que sustentam o papel desta rede em relação ao S-REM, os mecanismos celulares e sinápticos subjacentes a este controle são pouco conhecidos e permanecem sob intensa investigação. Para avançar no conhecimento desses mecanismos, caracterizou-se morfológica e funcionalmente uma fatia de tronco encefálico de rato, na qual as estruturas críticas para o controle do S-REM, i.e.: núcleos tegmentais laterodorsal e pedunculopontino, e sua projeção para o núcleo reticular pontis oralis (PnO) estão presentes e operantes. A inclusão do núcleo motor do trigêmeo na fatia permitiu detectar mudanças da excitabilidade das motoneuronas provocadas por manipulações farmacológicas do PnO, representativas das alterações do tônus muscular associados com operações semelhantes quando realizados in vivo. A utlização deste modelo in vitro de S-REM permitirá contribuir para a elucidação de estratégias neurais que operam em níveis intermedios de organização do SN de mamíferos para a geração e regulação de um estado comportamental.

Computerized electrocardiography in healthy conscious guinea pigs (Cavia porcellus) / Eletrocardiografia computadorizada em cobaios (Cavia porcellus) saudáveis e conscientes

The purpose of this study is to evaluate healthy conscious guinea pigs as a model for electrophysiology assessment and to describe normal electrocardiographic patterns in controlled laboratory environment, establishing the best QT formula for this method. Electrocardiographic recordings of fifty adult conscious guinea pigs were obtained using a computerized electrocardiography. The electrocardiographic measurements of three different tracings were analyzed. The results obtained established normal mean and range values for the parameters: heart rate, waves and intervals of P-QRS-T deflections, as well as the mean cardiac axis. Groups were separated by body weight: group 1 gathered animals with 500-699g and group 2 with animals 700-900g. No differences were found when measurements were compared between groups, showing no significant difference between weight/body sizes to the electrocardiographic parameters (P<0.05). The mean corrected QT values (QTc) obtained using diverse formulae were significantly different (P<0.05), were the most consistent was Van der Water (QTcV). QTcV values were strongly correlated (r=98) and 95% confidence interval 185.7 to 195.2ms.Considering its simplicity and reliability, the QTcV was deemed the most appropriate to be used for the correction of QT interval in conscious guinea pigs.The results of this study also suggest that the values found can be used as reference for the species.(AU)

O objetivo desse estudo foi avaliar cobaios hígidos e conscientes como modelos para estudos de eletrofisiologia e descrever os padrões eletrocardiográficos normais em ambiente laboratorial controlado, estabelecendo a melhor fórmula QT para esse método. Gravações eletrocardiográficas de cinquenta cobaios adultos conscientes foram obtidas usando eletrocardiografia computadorizada. As medidas eletrocardiográficas de três trechos diferentes foram analisadas. Os resultados estabeleceram média e desvio padrão para os parâmetros: frequência cardíaca, ondas e intervalos P-QRS-T, assim como o eixo cardíaco médio. Grupos foram separados de acordo com o peso: grupo 1 incluiu animais com 500-699g e o grupo 2 animais de 700-900g. Nenhuma diferença foi encontrada quando as medidas foram comparadas entre os grupos, mostrando que não há diferença significativa entre peso/tamanho corporal com os parâmetros eletrocardiográficos (p<0.05). As médias corrigidas dos valores do QT (QTc) obtidas usando diferentes fórmulas foram significativamente diferentes (p<0.05), sendo a mais consistente a de Van der Water (QTcV). Valores de QTcV fortemente correlacionam com o QT (r=98), com intervalo de confiança a 95% de 185.7 a 195.2 ms. Considerando a simplicidade e confiabilidade, o QTcV foi considerado apropriado para correção do intervalo QT em cobaios conscientes. Os resultados do presente estudo também sugerem que os valores encontrados possam ser utilizados como referência para essa espécie.(AU)

Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor / Características eletrofisiológicas do tremor na Doença de Parkinson e tremor essencial

Tremor in essential tremor (ET) and Parkinson’s disease (PD) usually present specific electrophysiologic profiles, however amplitude and frequency may have wide variations. Objective: To present the electrophysiologic findings in PD and ET. Method: Patients were assessed at rest, with posture and action. Seventeen patients with ET and 62 with PD were included. PD cases were clustered into three groups: predominant rest tremor; tremor with similar intensity at rest, posture and during kinetic task; and predominant kinetic tremor. Results: Patients with PD presented tremors with average frequency of 5.29±1.18 Hz at rest, 5.79±1.39 Hz with posture and 6.48±1.34 Hz with the kinetic task. Tremor in ET presented with an average frequency of 5.97±1.1 Hz at rest, 6.18±1 Hz with posture and 6.53±1.2 Hz with kinetic task. Seven (41.2%) also showed rest tremor. Conclusion: The tremor analysis alone using the methodology described here, is not sufficient to differentiate tremor in ET and PD. .

Os tremores observados no tremor essencial (TE) e na doença de Parkinson (DP) costumam apresentar perfis eletrofisiológicos específicos, embora amplitude e frequência possam ter grandes variações. Objetivo: Apresentar os resultados dos exames eletrofisiológicos na DP e no TE. Método: Pacientes foram avaliados em repouso, com postura e em ação. Foram incluídos 17 pacientes com TE e 62 com DP. Casos de DP foram divididos em três grupos: predomínio de tremor de repouso; tremor com intensidade semelhante em repouso, postura e tarefa cinética e tremor cinético predominante. Resultados: Pacientes com DP apresentaram tremores com frequência média de 5,29±1,18 Hz em repouso, 5,79±1.39 Hz com postura e 6,48±1,34 Hz com tarefa cinética. Tremor no TE apresentou frequência média 5,97±1,1Hz em repouso, 6,18±1Hz com postura e 6,53±1,2 Hz com tarefa cinética. Sete (41,2%) também apresentaram tremor de repouso. Conclusão: A análise do tremor per se, usando os métodos descritos neste estudo, não é suficiente para diferenciar o tremor no TE e DP. .

Bloqueo interauricular como sustrato anatómico-eléctrico de arritmias supraventriculares: síndrome de Bayés / Interatrial block as anatomical-electrical substrate for supraventricular arrhythmias: Bayes' syndrome

En este artículo hemos querido establecer que el bloqueo interauricular existe como entidad anatomoeléctrica y que debe ser considerado como un verdadero bloqueo. El bloqueo interauricular presenta diferentes grados al igual que otros bloqueos del sistema de conducción. Puede presentarse como expresión de remodelado puramente eléctrico o acompañar alteraciones estructurales que dilaten las aurículas. Se encuentra asociado a arritmias supraventriculares y es probablemente un predictor de accidente cerebrovascular cardioembólico. El bloqueo interauricular puede presentarse de manera transitoria, y en ciertas circunstancias clínicas, puede ser reversible. El aporte del mapeo endocavitario ha incrementado el conocimiento sobre su anatomía y fisiopatología, y posiblemente la magnetocardiografía podría contribuir al estudio no invasivo de esta entidad. La terminología a utilizar debería ser bloqueo interauricular de primer, segundo y tercer grado o alternativamente, y en función de simplificar: parcial o avanzado. La morfología de la onda P, en función de diagnosticar el grado avanzado, siempre debería ser tenida en cuenta. Para finalizar, debemos reconocer el aporte fundamental que el Dr. Bayés de Luna ha establecido sobre la relación del bloqueo interauricular con las arritmias supraventriculares conformando un síndrome arrítmico indiscutido; lo cual a nuestro criterio representa un aporte mayor al conocimiento de la electrocardiografía y la electrofisiología, y hace meritorio que este síndrome arrítmico sea denominado <

In this article we aimed to establish that interatrial block exists as an anatomical-electrical entity, which should be considered a true block. Interatrial block presents with different degrees as other blocks in the conduction system. It shows a correlation with the left atrium size, however, it can be seen in patients with normal atrial size too. Interatrial block is strongly associated with atrial arrhythmias and it could be considered a predictor of cardioembolic stroke. Interatrial block is an expression of atrial electrical remodeling and dysfunction. IAB can be transient and in certain clinical circumstances, may be reversible. The contribution of endocardial mapping has increased our knowledge of the anatomy and pathophysiology of interatrial block. Magnetocardiography could be a possible non-invasive procedure to further investigate this entity. The interatrial block classification should include first, second and third degree or alternatively, in order to simplify the terminology: partial or advanced. The P wave morphology should always be taking into consideration when diagnosing this condition. Finally, without the initial description of interatrial block made by Dr. Bayés de Luna, it would be impossible to understand interatrial block as an anatomical and electrical substrate for atrial arrhythmias. It is our opinion that this represents a major contribution to the knowledge of electrocardiography and electrophysiology, and makes commendable that this arrhythmic syndrome should be called <

Evaluation of nerve regeneration in diabetic rats

PURPOSE: To compare sciatic nerve regeneration between non-diabetic (control) and streptozotocin-induced diabetic Wistar rats. METHODS:Four subgroups were evaluated. CN: Non-diabetic rats submitted to neurorrhaphy (n=9); DN: Diabetic rats submitted to neurorrhaphy (n=9); CG: Non-diabetic rats submitted to nerve grafting (n=10); DG: Diabetic rats submitted to nerve grafting (n=9). The nerve regeneration was evaluated by walking track analysis (sciatic functional index), electrophysiological test, histomorphometric analysis and triceps surae muscle weight. RESULTS:At 60 days post-surgery, functional recovery of DN was similar to that of the non-diabetic rats (CN, CG), but DG didn't achieve the same. Evoked potential amplitudes showed no statistically significant differences among subgroups. Triceps surae muscle was heavier in CN. No statistically significant differences were observed between the control and diabetes subgroups with respect to histomorphometric analysis. CONCLUSION: After 60 days, DN had a functionally similar recovery to that of the control animals, whereas nerve grafting in diabetic rats didn't allow the same. The muscle atrophy was lower in CN. In the rest of evaluations, as electrophysiological and histomorphometric, diabetic rats were not different from control ones.

Correlación de hallazgos clínicos y alteraciones electrofisiológicas en pacientes con diagnóstico de síndrome de túnel del carpo atendidos en el Departamento de Medicina Física y Rehabilitación del HNGAI, en el período Enero-Diciembre 2012 / Correlation of clinical findings and electrophysiological alterations in patients with diagnosis of Carpal Tunnel Syndrome treated in the Department of Physical Medicine and Rehabilitation of the HNGAI, in the period January-December 2012

Objetivo: Determinar la correlación entre hallazgos clínicos y alteraciones electrofisiológicas en pacientes con diagnóstico de síndrome de túnel del carpo. Material y Métodos: Se realizó un estudio descriptivo, retrospectivo donde se estableció una correlación clínico-electrofisiológica en 100 pacientes atendidos en el Departamento de Medicina Física y Rehabilitación del Hospital Nacional Guillermo Almenara Irigoyen, en el periodo Enero-Diciembre 2012. Resultados: La edad promedio fue de 56.67 (rango de 32 a 85) años; observándose predominio en el sexo femenino (76 por ciento); la mayoría presento afectación unilateral 53 por ciento (mano derecha 35 por ciento). El 72 por ciento de los pacientes estudiados no presentaba ninguna condición asociada. En un 45 por ciento se encontró alteración electrofisiológicas. Se encontró que el signo de Phalen está más asociado a alteraciones electro fisiológico que el signo de Tinel. Conclusiones: La sintomatología (parestesias, dolor, debilidad) no se halla relacionada a alteraciones electrofisiológicas. La presencia de signo Tinel o Phalen está asociada de manera significativa con las alteraciones electro fisiológicas encontradas.

Objective: To determine correlation between clinical and electrophysiological abnormalities in patients diagnosed with carpal tunnel syndrome. Material and Methods: We made a descriptive, retrospective study to established clinical-electrophysiological correlation in 100 patients treated at the Department of Physical Medicine and Rehabilitation, National Hospital Guillermo Almenara Irigoyen, in the period January to December 2012. Results: Mean age was 56.67 years (range 32-85); with female predominance (76 per cent), most of them 53 per cent presented unilateral involvement (right hand 35 per cent). 72 per cent of the patients presented no associated condition. At 45 per cent patients were found electrophysiological alteration. We found that Phalen sign is more associated with electrophysiological abnormalities than Tinel sign. Conclusions: The symptoms (numbness, pain, weakness) are not related to electrophysiological abnormalities. The presence of Tinel or Phalen sign is significantly associated with electrophysiological abnormalities found.

La electrofisiología del Wolff-Parkinson-White en el paciente asintomático con actividad o riesgo profesional alto / The electrophysiology of Wolff-Parkinson-White in the asymptomatic patient with activity or with high professional risk

Objetivo: Describir las características electrofisiológicas en individuos con Wolff-Parkinson-White asintomático con actividad deportiva o alta responsabilidad profesional. Métodos: Se evaluaron 19 individuos, edad media 33 ± 13 años (grupo A). Las características electrofisiológicas fueron comparadas con un grupo control similar con WPW sintomático (grupo B). Resultados: En estado basal el periodo refractario anterógrado y la conducción anterógrada 1:1 sobre el fascículo accesorio fueron más largos en el grupo A (300 ± 48 ms vs 262 ± 32 ms, p < 0.05) y (355 ± 108 ms vs 307 ± 86 ms, p < 0.05), respectivamente. Ningún individuo del grupo A tuvo un periodo refractario anterógrado < 250 ms; y 58% no tuvieron conducción retrógrada sobre el fascículo accesorio vs 4% del grupo B (p< 0.001). La inducción de taquicardia fue significativamente menor (5.2%) en el grupo A vs grupo B (95%) (p < 0.001). Se indujo fibrilación auricular (FA) sólo en uno del grupo A vs en 32% grupo B (p< 0.001). Conclusión: Se confirman las características electrofisiológicas benignas en individuos asintomáticos comparados con sintomáticos. La deficiente conducción anterógrada junto con ausencia de conducción retrógrada explica la baja frecuencia de taquiarritmias y no apoyaría la investigación rutinaria en toda la población asintomática, pero debido a las posibles consecuencias, se mantiene la indicación sistemática con fines de ablación preventiva en el subgrupo de individuos asintomáticos con actividad deportiva o alta responsabilidad profesional.

Objective: Describe the electrophysiological characteristics in subjects with asymptomatic Wolff-Parkinson-White with sports activities or high professional responsibility. Methods: Nineteen subjects, mean age 33 ± 13 years (group A). The electrophysiological characteristics were compared with a matched group with symptomatic WPW (group B). Results: At baseline the anterograde refractory period and the anterograde conduction 1:1 over the accessory pathway were longer in group A (300 ± 48 ms vs 262 ± 32 ms, p <0.05 and 355 ± 108 ms vs 307 ± 86 ms, p <0.05), respectively. None of group A had a anterograde refractory period < 250 ms and 58% showed absence of retrograde conduction over the accessory pathway vs 4% of group B (p < 0.001). Induction of tachycardia was significantly less in group A (5%) than in group B (92%) (p < 0.001). Atrial fibrillation was induced in only one of group A vs 32% of group B (p< 0.001). Conclusion: We confirm the benign electrophysiological characteristics in asymptomatic compared to symptomatic subjects. Poor anterograde conduction along with absence of retrograde conduction explains the low frequency of tachyarrhythmias and would not support the routine investigation of all asymptomatic subjects. But, due to possible consequences, remains the systematic indication for preventive ablation in the subgroup of asymptomatic subjects with sporting activities or high professional responsibility.

Polineuropatia sensitiva induzida por talidomida e estudo eletrofisiológico do nervo sural como forma de screening diagnóstico: relato de caso / Thalidomide-induced sensory polyneuropathy and electrophysiological study of the sural nerve as a screening diagnosis: a case report

Polineuropatia é uma condição clínica freqüente com sintomatologia debilitante e o tratamento depende fundamentalmente da etiologia. Inúmeras são as causas possíveis deste tipo de distúrbio e o diagnóstico etiológico nem sempre é fácil. Neste relato de caso descrevemos um caso de um paciente com mieloma múltiplo que evoluiu com polineuropatia puramente sensitiva, comprovadapor estudo eletrofisiológico, induzida por talidomida.

Polyneuropathy is a common clinical condition with debilitating symptoms whose treatment dependson etiology. There are numerous possible causes of this type of disorder and the etiologicaldiagnosis is not always easy. In this case report we describe a case of a patient with multiple myeloma who developed purely sensory polyneuropathy, confirmed by electrophysiological study, induced by thalidomide.

Adaptação de prótese auditiva e a privação da audição unilateral: avaliação comportamental e eletrofisiológica / Hearing aid fitting and unilateral auditory deprivation: behavioral and electrophysiologic assessment

O fenômeno da Privação Auditiva Unilateral de Início Tardio foi reportado em 1984. No entanto, ainda se observa um expressivo número de adaptações de próteses auditivas unilaterais, nos casos de perdas auditivas bilaterais, justificadas por fatores não auditivos, tais como custo, vaidade, desinformação ou políticas públicas de saúde. OBJETIVO: Investigar, por meio de avaliação comportamental e eletrofisiológica, o desempenho auditivo de adultos que fazem uso de amplificação unilateral, comparados àqueles expostos à estimulação auditiva simétrica bilateral. MÉTODO: Participaram deste estudo 35 indivíduos adultos com perda auditiva sensorioneural bilateral simétrica, usuários regulares de prótese auditiva unilateral, bilateral e não usuários de prótese auditiva por meio de testes de avaliação comportamental e eletrofisiológica. RESULTADOS: A análise de variância revelou que, no grupo usuário de amplificação unilateral, a latência do P300 foi significantemente maior na orelha que sofreu a privação auditiva comparada a orelha com prótese auditiva (p < 0,05). Também foi encontrado desempenho significantemente pior deste grupo no reconhecimento de sentenças no ruído (LSP) realizado em campo livre. CONCLUSÃO: Os resultados reforçam os achados da literatura de que a privação auditiva unilateral pode levar a mudanças fisiológicas e perceptuais.

The phenomenon of Late-Onset Unilateral Auditory Deprivation was first reported in 1984. However, a high number of unilateral hearing aid fittings are still carried out in cases of bilateral hearing loss, justified by non-auditory factors such as cost, vanity, misinformation and public health policies. OBJECTIVE: To carry out behavioral and electrophysiological assessment of the auditory performance of adults using unilateral amplification compared with individuals exposed to bilateral symmetric auditory stimulation. METHOD: Thirty five adults, all with symmetric bilateral sensorineural hearing loss, regular users of unilateral hearing aid, bilateral hearing aids and not users of hearing aids, were assessed on behavioral and electrophysiological tests. RESULTS: Variance analysis revealed that in the unilaterally fitted group, P300 latency was significantly greater in ears with auditory deprivation compared with those fitted with the hearing aid (p < 0.05). This same group also had poorer performance on the Sentence Recognition Test in Noise held in free field. CONCLUSION: These results corroborate findings in the literature showing that unilateral auditory deprivation can lead to physiological and perceptual changes.