Facilitating the selection of raw materials: Evaluation of the effects of TCF and ECF bleaching sequences on different wood and non-wood pulps

Properties of cellulosic raw materials are known to vary widely among different sources. The interest in the usage of non-conventional fibers makes necessary a better knowledge of the peculiarities of each source and their behavior under different bleaching processes. ECF and TCF bleached pulps (ISO brightness≥ 82%) from eucalyptus, flax and sisal as well as cotton linters were analyzed. Eucalyptus showed the highest zero-span tensile strength (1.1-1.2 N.m/g), higher than that of sisal (0.85-0.95 N.m/g) and flax (0.7-0.8 N.m/g) which were also found to be linearly correlated to their viscosity regardless of the cellulose source. Sisal and eucalyptus showed the largest hemicelluloses content (≈13-16 %) while cotton linters appeared as a high-cellulose content (97.7 %)source for high-quality fibers. ECF and TCF bleaching processes produced different effects on fibers, as the latter showed a slightly lower quality than the former, difference that may not be significant if the great environmental benefit of TCF bleaching is considered. Finally, fiber surface was examined using SEM microscopy for a more complete assessment of raw materials

Luteinizing Hormone-Releasing Hormone in the Vomeronasal System and Terminal Nerve of the Hamster a

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74742/1/j.1749-6632.1987.tb36300.x.pd

PREVALENCE OF Entamoeba histolytica/Entamoeba dispar IN THE CITY OF CAMPINA GRANDE, IN NORTHEASTERN BRAZIL

There is a clear need to perform epidemiological studies to find the true prevalence of Entamoeba histolytica around the world. The evaluation of this prevalence has been hindered by the existence of two different species which are morphologically identical, but genetically different, namely E. histolytica, which causes amebiasis, and E. dispar, which is non-pathogenic. In Brazil, the E. dispar has been detected in communities in the Southeastern (SE) and Northeastern (NE) regions with poor sanitation. However, individuals infected with E. histolytica have been identified in other regions. There is an absence of reports on the prevalence of these parasites in the state of Paraíba, which also has areas with poor sanitary conditions where a high prevalence of the E. histolytica/E. dispar complex has been detected in children from urban slums. The present study evaluated the prevalence of E. histolytica and E. dispar in 1,195 asymptomatic children between two and 10 years of age, living in a sprawling urban slum in Campina Grande, in the state of Paraíba, in Northeastern Brazil. These children were examined and their feces samples were analyzed microscopically. A total of 553 children tested positive for the E. histolytica/E. dispar complex, and 456 of the positive samples were tested with the E. histolytica II® ELISA kit. All 456 samples were negative for the presence of the adhesin E. histolytica specific antigen. The evidence suggests that in this community E. histolytica is absent and E. dispar is the dominant species

Understanding the pathophysiology of epilepsy in an animal model: Pentylenetetrazole induces activation but not death of neurons of the medial extended amygdala

Introduction: Since middle of the 20th century the importance of amygdala in epilepsy it has suggested, although the basic mechanisms of this participation are still unknown. This ignorance increases when the different subdivisions of amygdala are considered, especially the medial amygdala. In this work we assess the involvement of the medial extended amygdala in an animal model of epilepsy and the consequences of its application in this brain structure. Material and methods: Forty eight adult Wistar male rats were used, of which 24 of them received i.p. injections of pentylenetetrazole, and 24 (controls) were injected with saline. After 2, 6, 12 and 24 h survival, animals were fixed; the brains were sectioned serially and stained for fos (immunochemistry) and for neuronal death with the A-Cu-Ag technique. Data were analysed using two-way ANOVA followed by the Fisher post hoc test. Results: Very few or no fos-immunoreactive neurons were seen in control animals. In experimental animals, fos was rapidly induced in structures of medial extended amygdala with peak levels at 2 h. Marked fos immunoreactivity persisted up to 12 h followed by a gradual return to baseline at 24 h. However, status epilepticus did not induced neuronal death. Conclusions: These results show involvement of medial extended amygdala in epileptic mechanisms with an inhibitory component. However, neuronal death is not a consequence of status epilepticus-induced by pentylentetrazole. Resumen: Introducción: Desde mitad del siglo xx se ha apuntado a la importancia de la amígdala en la epilepsia, aunque los mecanismos básicos de esta participación en su mayoría son aún desconocidos. Esta ignorancia es aún mayor cuando se tienen en cuenta las distintas subdivisiones de la amígdala, especialmente sus partes mediales. En este trabajo evaluamos la participación de la amígdala extendida medial en un modelo animal de epilepsia, así como las consecuencias que tiene el epileptógeno en esta estructura cerebral. Material y métodos: Se utilizaron ratas adultas Wistar machos (n = 48); 24 animales recibieron inyecciones intraperitoneales de pentilentetrazol y 24, de salina. Luego de 2, 6, 12 y 24 h de sobrevida, los animales se fijaron, y sus cerebros se cortaron seriadamente y se procesaron para fos (inmunoquímica) y muerte neuronal con la técnica A-Cu-Ag. Los datos se analizaron con un ANOVA de 2 vías seguido de un test post-hoc (LSD de Fisher). Resultados: Muy poca activación fos se halla en animales controles. En animales experimentales, fos fue rápidamente inducida en la amígdala extendida medial a las 2 h. Esta activación fue sostenida hasta las 12 h y retornó a valores basales a las 24 h. Sin embargo, el estado epiléptico no produjo muerte neuronal. Conclusiones: Se demuestra así una participación de la amígdala extendida medial en mecanismos epilépticos en los cuales subyace un componente inhibitorio. Sin embargo, el estado epiléptico inducido no produce muerte neuronal en esta estructura. Keywords: Medial extended amygdala, Epilepsy, Fos, GABA, Pentylentetrazole, Palabras clave: Amígdala extendida medial, Epilepsia, Fos, GABA, Pentilentetrazo

Descifrando la fisiopatología de la epilepsia en un modelo animal: el pentilentetrazol induce la activación pero no la muerte de las neuronas de la amígdala extendida medial

Resumen: Introducción: Desde mitad del siglo xx se ha apuntado a la importancia de la amígdala en la epilepsia, aunque los mecanismos básicos de esta participación en su mayoría son aún desconocidos. Esta ignorancia es aún mayor cuando se tienen en cuenta las distintas subdivisiones de la amígdala, especialmente sus partes mediales. En este trabajo evaluamos la participación de la amígdala extendida medial en un modelo animal de epilepsia, así como las consecuencias que tiene el epileptógeno en esta estructura cerebral. Material y métodos: Se utilizaron ratas adultas Wistar machos (n = 48); 24 animales recibieron inyecciones intraperitoneales de pentilentetrazol y 24, de salina. Luego de 2, 6, 12 y 24 h de sobrevida, los animales se fijaron, y sus cerebros se cortaron seriadamente y se procesaron para fos (inmunoquímica) y muerte neuronal con la técnica A-Cu-Ag. Los datos se analizaron con un ANOVA de 2 vías seguido de un test post-hoc (LSD de Fisher). Resultados: Muy poca activación fos se halla en animales controles. En animales experimentales, fos fue rápidamente inducida en la amígdala extendida medial a las 2 h. Esta activación fue sostenida hasta las 12 h y retornó a valores basales a las 24 h. Sin embargo, el estado epiléptico no produjo muerte neuronal. Conclusiones: Se demuestra así una participación de la amígdala extendida medial en mecanismos epilépticos en los cuales subyace un componente inhibitorio. Sin embargo, el estado epiléptico inducido no produce muerte neuronal en esta estructura. Abstract: Introduction: Since middle of the 20th century the importance of amygdala in epilepsy it has suggested, although the basic mechanisms of this participation are still unknown. This ignorance increases when the different subdivisions of amygdala are considered, especially the medial amygdala. In this work we assess the involvement of the medial extended amygdala in an animal model of epilepsy and the consequences of its application in this brain structure. Material and methods: Forty eight adult Wistar male rats were used, of which 24 of them received i.p. injections of pentylenetetrazole, and 24 (controls) were injected with saline. After 2, 6, 12 and 24 h survival, animals were fixed; the brains were sectioned serially and stained for fos (immunochemistry) and for neuronal death with the A-Cu-Ag technique. Data were analysed using two-way ANOVA followed by the Fisher post hoc test. Results: Very few or no fos-immunoreactive neurons were seen in control animals. In experimental animals, fos was rapidly induced in structures of medial extended amygdala with peak levels at 2 h. Marked fos immunoreactivity persisted up to 12 h followed by a gradual return to baseline at 24 h. However, status epilepticus did not induced neuronal death. Conclusions: These results show involvement of medial extended amygdala in epileptic mechanisms with an inhibitory component. However, neuronal death is not a consequence of status epilepticus-induced by pentylentetrazole. Palabras clave: Amígdala extendida medial, Epilepsia, Fos, GABA, Pentilentetrazol, Keywords: Medial extended amygdala, Epilepsy, Fos, GABA, Pentylentetrazol