Envenomations by Bothrops and Crotalus Snakes Induce the Release of Mitochondrial Alarmins

Skeletal muscle necrosis is a common manifestation of viperid snakebite envenomations. Venoms from snakes of the genus Bothrops, such as that of B. asper, induce muscle tissue damage at the site of venom injection, provoking severe local pathology which often results in permanent sequelae. In contrast, the venom of the South American rattlesnake Crotalus durissus terrificus, induces a clinical picture of systemic myotoxicity, i.e., rhabdomyolysis, together with neurotoxicity. It is known that molecules released from damaged muscle might act as ‘danger’ signals. These are known as ‘alarmins’, and contribute to the inflammatory reaction by activating the innate immune system. Here we show that the venoms of B. asper and C. d. terrificus release the mitochondrial markers mtDNA (from the matrix) and cytochrome c (Cyt c) from the intermembrane space, from ex vivo mouse tibialis anterior muscles. Cyt c was released to a similar extent by the two venoms whereas B. asper venom induced the release of higher amounts of mtDNA, thus reflecting hitherto some differences in their pathological action on muscle mitochondria. At variance, injection of these venoms in mice resulted in a different time-course of mtDNA release, with B. asper venom inducing an early onset increment in plasma levels and C. d. terrificus venom provoking a delayed release. We suggest that the release of mitochondrial ‘alarmins’ might contribute to the local and systemic inflammatory events characteristic of snakebite envenomations

Biofeedback and progressive relaxation treatment of sleep-onset insomnia

Previous research suggests that self-defined insomniacs are distinguished from normals by high levels of anxiety and physiological arousal, which might be mitigated by muscle relaxation. This study assessed the relative effects of frontal EMG biofeedback, progressive relaxation, and a placebo set of “relaxation” exercises on the sleep of 18 onset insomniacs. Each subject was trained in one of these three methods for six half-hour sessions and slept in the laboratory for two consecutive nights before and after training. The experimental groups demonstrated significant decreases in physiological activity during training while changes in the control group were minimal. Reductions in sleep-onset time were: biofeedback group, 29.66 minutes; progressive relaxation group, 22.92 minutes; control group, 2.79 minutes. The experimental groups improved significantly ( p<.05 ) more than the control group, but did not differ from each other. No significant relationships between physiological levels and sleep-onset time were found, which suggests that muscle relaxation alone was not responsible for subjects' improvements. Since 20 minutes of daily practice were required to achieve an approximate 30-minute decrease in sleep-onset time, the practical utility of the methods is questioned.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44085/1/10484_2005_Article_BF01001167.pd

Opciones para la utilizaci?n sostenible de la biodiversidad: la experiencia del INBio

Ilus. 1 ref

Paroxysmal events during prolonged video-electroencephalography monitoring in refractory epilepsy

Introduction: Given that epileptic seizures and non-epileptic paroxysmal events have similar clinical manifestations, using specific diagnostic methods is crucial, especially in patients with drug-resistant epilepsy. Prolonged video electroencephalography monitoring during epileptic seizures reveals epileptiform discharges and has become an essential procedure for epilepsy diagnosis. The main purpose of this study is to characterise paroxysmal events and compare patterns in patients with refractory epilepsy. Methods: We conducted a retrospective analysis of medical records from 91 patients diagnosed with refractory epilepsy who underwent prolonged video electroencephalography monitoring during hospitalisation. Results: During prolonged video electroencephalography monitoring, 76.9% of the patients (n = 70) had paroxysmal events. The mean number of events was 3.4 ± 2.7; the duration of these events was highly variable. Most patients (80%) experienced seizures during wakefulness. The most common events were focal seizures with altered levels of consciousness, progressive bilateral generalised seizures and psychogenic non-epileptic seizures. Regarding all paroxysmal events, no differences were observed in the number or type of events by sex, in duration by sex or age at onset, or in the number of events by type of event. Psychogenic nonepileptic seizures were predominantly registered during wakefulness, lasted longer, started at older ages, and were more frequent in women. Conclusions: Paroxysmal events recorded during prolonged video electroencephalography monitoring in patients with refractory epilepsy show similar patterns and characteristics to those reported in other latitudes. Resumen: Introducción: La inexistencia de signos clínicos que diferencien entre crisis epilépticas y episodios paroxísticos no epilépticos hace necesario utilizar métodos diagnósticos específicos, principalmente en pacientes refractarios al tratamiento farmacológico. La monitorización prolongada con videoelectroencefalografía durante las crisis epilépticas evidencia descargas epileptiformes en el EEG ictal y constituye una prueba fundamental para su diagnóstico. La presente investigación pretende caracterizar los eventos paroxísticos y comparar los patrones encontrados en pacientes con diagnóstico de epilepsia refractaria. Métodos: Se realizó un estudio y análisis retrospectivo a partir de los registros médicos de la monitorización prolongada con video EEG de 91 pacientes diagnosticados con epilepsia refractaria durante su internamiento. Resultados: Durante el videoelectroencefalograma prolongado el 76,9% (n = 70) de los pacientes presentaron eventos paroxísticos. El número promedio de eventos fue 3,4 (± 2,7) y su duración fue muy variable. La mayoría de los pacientes (80,0%) presentó las crisis durante vigilia y los principales tipos de eventos registrados fueron: focales con alteración de la conciencia, evolutivos a crisis convulsivas bilaterales y crisis psicógenas no epilépticas. Considerando la totalidad de los eventos paroxísticos, no se objetivan diferencias en cuanto al número o tipo de eventos descritos según el sexo, la edad de inicio de la enfermedad o el sexo y la duración de los eventos, o al número de eventos según el tipo. Las crisis psicógenas no epilépticas se registran predominantemente en vigilia, presentan mayor duración, se inician más tardíamente y ocurren principalmente en mujeres. Conclusiones: Los eventos paroxísticos observados durante la monitorización prolongada con videoelectroencefalograma de pacientes internados con epilepsia refractaria muestran patrones y características similares a los descritos en otras latitudes. Keywords: Paroxysmal events, Prolonged video electroencephalography monitoring, Epilepsy monitoring unit, Refractory epilepsy, Epileptic seizures, Psychogenic non-epileptic seizures, Palabras clave: Eventos paroxísticos, Videoelectroencefalograma prolongado, Unidad de monitorización, Epilepsia refractaria, Crisis epilépticas, Crisis psicógenas no epiléptica

Eventos paroxísticos durante la monitorización prolongada con videoelectroencefalografía en epilepsia refractaria

Resumen: Introducción: La inexistencia de signos clínicos que diferencien entre crisis epilépticas y episodios paroxísticos no epilépticos hace necesario utilizar métodos diagnósticos específicos, principalmente en pacientes refractarios al tratamiento farmacológico. La monitorización prolongada con videoelectroencefalografía durante las crisis epilépticas evidencia descargas epileptiformes en el EEG ictal y constituye una prueba fundamental para su diagnóstico. La presente investigación pretende caracterizar los eventos paroxísticos y comparar los patrones encontrados en pacientes con diagnóstico de epilepsia refractaria. Métodos: Se realizó un estudio y análisis retrospectivo a partir de los registros médicos de la monitorización prolongada con video EEG de 91 pacientes diagnosticados con epilepsia refractaria durante su internamiento. Resultados: Durante el videoelectroencefalograma prolongado el 76,9% (n = 70) de los pacientes presentaron eventos paroxísticos. El número promedio de eventos fue 3,4 (± 2,7) y su duración fue muy variable. La mayoría de los pacientes (80,0%) presentó las crisis durante vigilia y los principales tipos de eventos registrados fueron: focales con alteración de la conciencia, evolutivos a crisis convulsivas bilaterales y crisis psicógenas no epilépticas. Considerando la totalidad de los eventos paroxísticos, no se objetivan diferencias en cuanto al número o tipo de eventos descritos según el sexo, la edad de inicio de la enfermedad o el sexo y la duración de los eventos, o al número de eventos según el tipo. Las crisis psicógenas no epilépticas se registran predominantemente en vigilia, presentan mayor duración, se inician más tardíamente y ocurren principalmente en mujeres. Conclusiones: Los eventos paroxísticos observados durante la monitorización prolongada con videoelectroencefalograma de pacientes internados con epilepsia refractaria muestran patrones y características similares a los descritos en otras latitudes. Abstract: Introduction: Given that epileptic seizures and non-epileptic paroxysmal events have similar clinical manifestations, using specific diagnostic methods is crucial, especially in patients with drug-resistant epilepsy. Prolonged video electroencephalography monitoring during epileptic seizures reveals epileptiform discharges and has become an essential procedure for epilepsy diagnosis. The main purpose of this study is to characterise paroxysmal events and compare patterns in patients with refractory epilepsy. Methods: We conducted a retrospective analysis of medical records from 91 patients diagnosed with refractory epilepsy who underwent prolonged video electroencephalography monitoring during hospitalisation. Results: During prolonged video electroencephalography monitoring, 76.9% of the patients (n = 70) had paroxysmal events. The mean number of events was 3.4 ± 2.7; the duration of these events was highly variable. Most patients (80%) experienced seizures during wakefulness. The most common events were focal seizures with altered levels of consciousness, progressive bilateral generalized seizures and psychogenic non-epileptic seizures. Regarding all paroxysmal events, no differences were observed in the number or type of events by sex, in duration by sex or age at onset, or in the number of events by type of event. Psychogenic nonepileptic seizures were predominantly registered during wakefulness, lasted longer, started at older ages, and were more frequent in women. Conclusions: Paroxysmal events recorded during prolonged video electroencephalography monitoring in patients with refractory epilepsy show similar patterns and characteristics to those reported in other latitudes. Palabras clave: Eventos paroxísticos, Videoelectroencefalograma prolongado, Unidad de monitorización, Epilepsia refractaria, Crisis epilépticas, Crisis psicógenas no epilépticas, Keywords: Paroxysmal events, Prolonged video electroencephalography monitoring, Epilepsy monitoring unit, Refractory epilepsy, Epileptic seizures, Psychogenic non-epileptic seizure

Unusual Microbial Xylanases from Insect Guts

Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial DNA isolated from insect intestinal tracts from the orders Isoptera (termites) and Lepidoptera (moths). Using a targeted functional assay, these environmental DNA libraries were screened for genes that encode proteins with xylanase activity. Several novel xylanase enzymes with unusual primary sequences and novel domains of unknown function were discovered. Phylogenetic analysis demonstrated remarkable distance between the sequences of these enzymes and other known xylanases. Biochemical analysis confirmed that these enzymes are true xylanases, which catalyze the hydrolysis of a variety of substituted β-1,4-linked xylose oligomeric and polymeric substrates and produce unique hydrolysis products. From detailed polyacrylamide carbohydrate electrophoresis analysis of substrate cleavage patterns, the xylan polymer binding sites of these enzymes are proposed