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Sample records for axonal inducida por

  1. Osteomalacia inducida por tumor: hemangiopericitoma rinosinusal

    Directory of Open Access Journals (Sweden)

    Enriqueta M. Serafini

    2013-02-01

    Full Text Available La osteomalacia inducida por tumor es una rara enfermedad del metabolismo óseo caracterizada por el aumento en la excreción de fosfato a nivel renal seguido de hipofosfatemia. Es causada por agentes fosfatúricos producidos por determinados tumores. La resección total del tumor resulta en la completa reversión de las anormalidades bioquímicas, la desaparición de las manifestaciones clínicas y los hallazgos en los estudios por imágenes. Presentamos el caso de un varón de 61 años con cuadro clínico y laboratorio compatibles con osteomalacia oncogénica inducida por tumor mesenquimático de localización rinosinusal. En nuestro caso el diagnóstico histológico correspondió a una neoplasia de tipo vascular: hemangiopericitoma.

  2. Asma inducida por el ejercicio.

    OpenAIRE

    Laurencena, Soledad

    2010-01-01

    El asma inducido por el ejercicio es una sensación de dificultad respiratoria, con la presencia de tos, sibilancias y opresión torácica tras realizar un esfuerzo físico. Sería el broncoespasmo transitorio que ocurre tras un ejercicio mantenido de tres a ocho minutos de duración al ochenta por ciento o más de la frecuencia cardíaca máxima. Se realizó un estudio transversal, descriptivo no experimental, tomando una muestra de 100 personas, entre 14 y 18 años, que estudian el ...

  3. toxicidad neuroendocrina inducida por cadmio

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    A Romero

    2008-01-01

    Full Text Available El cadmio es un agente químico tóxico importante debido a su creciente nivel en el medio ambiente como resultado de prácticas industriales y agrícolas. Como perturbador endocrino, el cadmio modifica la secreción de hormonas hipofisarias. Los efectos indirectos del cadmio provocan la generación de especies reactivas de oxígeno y reducen la actividad de las proteínas implicadas en las defensas antioxidantes. La melatonina es conocida como un potente antioxidante, scavenger de radicales libres y quelante de metales sintetizada en la glándula pineal. De esta manera, las acciones antioxidantes de esta indolamina protegen frente a la peroxidación lipídica y el daño oxidativo de los radicales y de sus productos tóxicos. Los trabajos recopilados en esta revisión ponen de manifiesto la capacidad antioxidante de la melatonina y, por lo tanto, su posible papel protector frente a la toxicidad del cadmio en lo que se refiere al estrés oxidativo y peroxidación lipídica inducidos por la exposición a este metal.

  4. Hipoglucemia inducida por carcinoma adrenal

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    Jimena Soutelo

    2013-08-01

    Full Text Available El carcinoma suprarrenal es una neoplasia maligna infrecuente y de mal pronóstico. La presentación clínica más común es originada por la producción hormonal excesiva, mientras que el desarrollo de hipoglucemia sintomática es excepcional. Presentamos el caso de una mujer de 37 años que ingresó al hospital por síntomas de hipoglucemias graves, hipertensión arterial, hipopotasemia y amenorrea secundaria. En el laboratorio se halló hipoglucemia con insulina inhibida y niveles de andrógenos en rango tumoral. La tomografía computarizada (TC de abdomen y pelvis mostró voluminosa formación heterogénea de aspecto sólido sin plano de clivaje con respecto al parénquima hepático e intenso realce con contraste. Luego de la extirpación de la masa retroperitoneal, evolucionó con valores de glucemia y potasemia normales, estabilizó la presión arterial y recuperó los ciclos menstruales.

  5. Osteoporosis inducida por glucocorticoides Glucocorticoid induced osteoporosis

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    R. Gutiérrez-Polo

    2003-01-01

    Full Text Available Los glucocorticoides son un grupo de fármacos que se emplean muy frecuentemente en la práctica médica por su indiscutible utilidad. La osteoporosis inducida por éstos supone el principal efecto adverso derivado de su administración sistémica y prolongada, constituyendo la causa más frecuente de osteoporosis secundaria. Comporta además una importante repercusión sanitaria y socioeconómica como consecuencia de las complicaciones que ocasiona, como son las diferentes fracturas óseas por fragilidad, sobre todo vertebrales, y la discapacidad funcional resultante. Se produce de forma temprana, siendo más rápida la pérdida ósea en los meses siguientes a la instauración de dicha terapia, en relación fundamentalmente con la dosis diaria. La patogenia de este tipo de osteoporosis es multifactorial, pero destaca el efecto inhibidor que presentan los glucocorticoides sobre la formación ósea. El manejo adecuado de este serio problema de salud requiere una actitud activa, que sin embargo no es lo suficientemente óptima en la actualidad. Incluye inicialmente las mismas medidas diagnósticas, preventivas y terapéuticas disponibles para otros casos de osteoporosis, pero con ciertas matizaciones y particularidades, especialmente las concernientes al propio manejo de los corticosteroides. Es conveniente un plan multidisciplinar, que se ha mostrado efectivo, principalmente si se realiza de forma temprana desde el inicio de la terapia. No obstante, quedan aún muchas cuestiones por esclarecer tanto en aspectos referentes a la corticoterapia, en general, como a la osteoporosis ocasionada, en particular. Es necesario el estudio y la búsqueda de nuevas terapias que mejoren la efectividad conseguida con las actuales para minimizar las repercusiones adversas que tiene para la salud de estos enfermos la administración de glucocorticoides.Glucocorticoids are a group of drugs widely used in medical practice due to their unquestionable utility

  6. ACATISIA INDUCIDA POR TIETILPERAZINA EN PACIENTE EMBARAZADA

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    Vera,Gabriela; Varas,Aldo

    2002-01-01

    La acatisia es un efecto lateral neurológico agudo común a diversos fármacos que actúan a nivel dopaminérgico, su manifestación fundamental es la inquietud psicomotora, es importante diagnosticar y tratar precozmente este síndrome. Tietilperazina es una fenotiazina cuyo efecto antiemético es usado en diversas circunstancias clínicas, presentamos el caso de una paciente hospitalizada por hiperemesis gravídica que es derivada a psiquiatría por la presencia de síntomas aparentemente ansiosos. El...

  7. EXCRECION FRACCIONAL DE UREA BAJA EN HIPONATREMIA INDUCIDA POR HIPOTIROIDISMO

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    Musso CG

    2005-02-01

    Full Text Available ABSTRACTHypothyroidism can cause disturbance of renal hemodinamics, kidney histology, water and electrolyte metabolism, being hyponatremia and glomerular filtration reduction their low prevalent but most significant consequences. All these changes are largely corrected by substitution of exogenous thyroid hormone.Fractional excretion of urea (FEU is a useful index in the evaluation of hyponatremia. However, it was not still reported in the literature the FEU value in hyponatremia induced by hypothyroidism. Because of that we presented a case report showing that the value of FEU and fractional excretion of sodium (FENa were low (FEU: 29% and high (FENa: 2.2 % respectively in a severe hypothyroid patient. Treatment based on thyroid hormone normalized both indeces.RESUMEN:El hipotiroidismo puede causar alteraciones del metabolismo del agua, los electrolitos, la hemodinamia e histología renales, siendo la hiponatremia y la reducción del filtrado glomerular sus consecuencias más significativas, pero poco prevalentes. Todos estos cambios son corregibles con el suministro de hormona tiroidea exógena.La excreción fraccional de urea (EFU es un índice útil en la evaluación de la hiponatremia, pero no se ha descripto aun el valor que este índice alcanza en la hiponatremia inducida por hipotiroidismo. En el presente reporte mostramos que la EFU y excreción fraccional de sodio (EFNa fueron baja (EFU: 29% y alta (EFNa: 2.2% respectivamente en un paciente que padecía hipotiroidismo severo. El tratamiento con hormona tiroidea normalizó el valor de ambos índices.

  8. Hipertensión inducida por el embarazo y peso de los productos al nacer

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    Nicolás Padilla Raygoza; Rosalina Díaz-Guerrero; Ma. Laura Ruiz Paloalto; Caitlin M. Canfield; Alejandro A. Avecilla Hernández

    2013-01-01

    Objetivo. Medir la asociación que existe entre la hipertensión inducida por el embarazo y el peso al nacer de los neonatos, en el Hospital General de Celaya. Tipo de estudio. Observacional, transversal y analítico. Sujetos: 1) Registros de mujeres embarazadas (n = 5 478), admitidas para su resolución obstétrica, en el Hospital General de Celaya durante el año 2008, y 2) registros del peso al nacer de los neonatos de estas mujeres. Variables: 1) Hipertensión inducida por el embarazo (presión a...

  9. Osteomalacia inducida por tumor: hemangiopericitoma rinosinusal Tumor-induced osteomalacia: rhinosinusal hemangiopericytoma

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    Enriqueta M. Serafini

    2013-02-01

    Full Text Available La osteomalacia inducida por tumor es una rara enfermedad del metabolismo óseo caracterizada por el aumento en la excreción de fosfato a nivel renal seguido de hipofosfatemia. Es causada por agentes fosfatúricos producidos por determinados tumores. La resección total del tumor resulta en la completa reversión de las anormalidades bioquímicas, la desaparición de las manifestaciones clínicas y los hallazgos en los estudios por imágenes. Presentamos el caso de un varón de 61 años con cuadro clínico y laboratorio compatibles con osteomalacia oncogénica inducida por tumor mesenquimático de localización rinosinusal. En nuestro caso el diagnóstico histológico correspondió a una neoplasia de tipo vascular: hemangiopericitoma.Tumor-induced osteomalacia is a rare disease of bone metabolism. The characteristic of this disease is an increase in phosphate excretion followed by hypophosphatemia, due to phosphaturic agents produced by different types of tumors. Tumor resection results in complete resolution of clinical, biochemical and radiological abnormalities. We present the case of a 61 year old man with signs, symptoms and laboratory findings consistent with oncogenic osteomalacia due to a rhino-sinusal mesenchymal tumor. The histological diagnosis showed a vascular neoplasm: hemangiopericytoma.

  10. Hepatotoxicidad inducida por azatioprina en paciente con enfermedad de Crohn

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    D. Ruiz-Clavijo

    2013-08-01

    Full Text Available Los inmunosupresores se encuentran entre los grupos farmacológicos con mayor potencial teórico de inducir reacciones adversas, entre ellas las hepáticas. Presentamos el caso de un paciente de 35 años con enfermedad de Crohn en tratamiento con azatioprina por corticodependencia al que se le diagnosticó tras realización de una biopsia hepática de hiperplasia nodular regenerativa secundaria a este tratamiento.

  11. D-002 (Abexol®) sobre la úlcera duodenal inducida por cisteamina

    OpenAIRE

    Daisy Carbajal; Vivian Molina; Lourdes Arruzazabala; Rosa Más

    2005-01-01

    D-002 (Abexol®) es un producto natural aislado y purificado de la cera de abejas (Apis mellifera), que consiste en una mezcla bien definida de alcoholes alifáticos primarios. Previamente ha sido demostrado que este producto posee efecto antiulceroso, a partir de la protección de la mucosa gástrica en úlceras inducidas por diversos agentes con un mecanismo citoprotector. En el presente estudio se realizaron ensayos para determinar si el D-002 mostraba una acción protectora en la úlcera duodena...

  12. Prevalencia y severidad de la disfunción intestinal inducida por opioides

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    Rafael Gálvez; Mariano Provencio; Manuel Cobo; Cristina Pérez; Concha Pérez; Jaume Canal

    2014-01-01

    Objetivo: Analizar la prevalencia y severidad de los síntomas de disfunción intestinal inducida por opioides (DIO). Diseño: Estudio epidemiológico, observacional y transversal. Emplazamiento: Seis hospitales españoles. Participantes: Trescientos diecisiete pacientes en régimen ambulatorio con diagnóstico de dolor oncológico o dolor crónico no oncológico tratados con un único opioide mayor. Mediciones principales: La prevalencia de los síntomas de DIO y su severidad se midió usando...

  13. Marcadores de estrés oxidativo en aterogénesis inducida por hiperfibrinogenemia

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    Báez,María C; Táran,Mariana D; Campana,Vilma; Simes, Juan C.; Pons, Patricia; Atilio-Palma,José; Moya, Mónica

    2009-01-01

    Introducción: Estudiar el factor de necrosis tumoral alfa (TNF-α), el óxido nítrico (ON) y la citrulina en ratas con lesiones aterogénicas inducida por hiperfibrinogenemia, y su repercusión morfológica mitocondrial en el músculo liso aórtico. Material y métodos: Inducción de hiperfibrinogenemia por inyección de adrenalina (0,1 mg/rata/día), estudiando: A) control, B) injuriados múltiples por 30 días y, C) injuriados múltiples por 60 días. Citrulina (mM) y ON (μM): espectrofotometría...

  14. D-002 (Abexol® sobre la úlcera duodenal inducida por cisteamina

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    Daisy Carbajal

    2005-01-01

    cimetidina, conocido antagonista de los receptores H2, a la misma dosis, si bien la eficacia de la cimetidina fue superior, ya que a 400 mg/kg se observa una mayor inhibición del desarrollo de la úlcera duodenal (76 %. El mecanismo de las úlceras duodenales resulta muy dependiente de ácido, hecho por el cual, fueron necesarias dosis más elevadas de D-002 para observar dicha protecci ón. Los resultados demuestran que la administración oral de D-002 a dosis altas (200 y 400 mg/kg, protege la mucosa gástrica de las úlceras duodenales inducidas por cisteamina, sugiriendo un valor potencial para la terapia de estas úlceras.

  15. Corrosión inducida por microorganismos en la industria papelera

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    Blanco, A.

    1998-05-01

    Full Text Available Microbial deposits (slime or biofilm formation is one of the most important problems in the paper industry. Slime formation cause a reduction of the final product quality (spots, holes, odours, as well as in the production and equipment life, due to a greater number of web breaks, down time for cleaning and maintenance of the machinery, corrosion, etc. Microbiologically-induced corrosion cause an important economic losses due to the reduction of the equipment life. In microbially-induced corrosion studies is basic the rapid and precise determination of the evolution of slime growth on metallic surfaces. Thus, the goal of the present work have been the development of a methodology that leads to characterize the population of aerobic bacteria that compose the slimes of a board mill by means of multiparametric flow cytometry, using two different angles of light scattering and the total protein content as parameters, as first step of the studies of microbiologically-induced corrosion.

    De todos los problemas que aparecen en la industria de papel y cartón, la formación de depósitos microbiológicos (biofilm o slime es uno de los más importantes, ya que causa problemas tanto en la calidad del producto (suciedad, agujeros, olores como en el proceso (paradas no programadas, corrosión, malos olores, producción de gases tóxicos, etc.. La corrosión inducida por microorganismos en la industria papelera produce grandes pérdidas económicas debido a la necesidad de sustituir los materiales más frecuentemente. En los estudios de corrosión inducida por microorganismos (CIM es imprescindible determinar de una forma rápida y precisa la evolución del slime sobre las superficies metálicas. Por tanto, el objetivo de este trabajo ha sido el desarrollo de una metodología que permita caracterizar la población de bacterias de los slimes de una fábrica de cartón mediante citometría de flujo multiparamétrica, tomando

  16. Efecto de un nuevo xanthanólido sesquiterpeno sobre la activación de mastocitos inducida por neurópeptidos pro-inflamatorios

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    Vargas, P.; Martino, E; Fogal, T.; Tonn, C.; Penissi, A.

    2009-01-01

    Los mastocitos son células del tejido conectivo que participan en la génesis y modulación de las respuestas inflamatorias celulares. En trabajos previos hemos demostrado que xanthatina (xanthanólido sesquiterpeno aislado de Xanthium cavanillesii Schouw) inhibe la activación de mastocitos inducida por secretagogos experimentales. Sin embargo, se desconoce su efecto sobre la activación de mastocitos inducida por estímulos fisiopatológicos. Estos...

  17. Cardiomiopatía inducida por estrés (Takotsubo en una paciente con anorexia nerviosa

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    Sabrina Vadalá

    2014-06-01

    Full Text Available Presentamos el caso de una mujer con diagnóstico de anorexia nerviosa que desarrolló cardiomiopatía de takotsubo precipitada por estrés emocional y alteraciones del medio interno. Evolucionó favorablemente con manejo conservador. Los casos de cardiomiopatía inducida por estrés, descriptos en pacientes con trastornos de la conducta alimentaria, suelen alcanzar mayor gravedad y se asocian con la prolongación del intervalo QT por desequilibrios electrolíticos, arritmias ventriculares e hipoglucemia. Se realiza una revisión del compromiso cardiovascular en pacientes con anorexia nerviosa.

  18. Capacidad antiteratogénica del resveratrol en diabetes inducida por estreptozotocina en ratas

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    Ninna Leslie Trejo-González

    Full Text Available Objetivos. Evaluar la capacidad antihiperglucémica y antiteratogénica del resveratrol en ratas inducidas a diabetes por estreptozotocina. Materiales y métodos. Estudio de tipo experimental. Se tuvieron tres grupos, de cinco ratas Wistar preñadas cada uno, dos de los cuales fueron tratados el cuarto día de gestación con una dosis de estreptozotocina de 50 mg/kg, disuelta en tampón de citratos, y el otro fue considerado como control, y solo se le administró el tampón de citratos. A uno de los grupos inducidos con estreptozotocina se le administró resveratrol a dosis de 100 mg/kg durante los días 8 al 12 de gestación, cuando sucede la neurulación. Los fetos se obtuvieron el día 19 de gestación y se les realizó un análisis morfológico, y en el hígado fetal se determinó la actividad de las enzimas depuradoras de especies reactivas catalasa, superóxido dismutasa y glutatión peroxidasa. Resultados. La administración de resveratrol (DM+R revierte los parámetros a valores similares a los del grupo control. Las actividades de catalasa y de glutatión peroxidasa, se vieron incrementadas en el grupo tratado con resveratrol con respecto al grupo diabético, en cuanto a la frecuencia de malformaciones en el grupo control y en el grupo tratado con resveratrol no presentaron malformaciones, mientras que en las ratas con diabetes inducida, se encontró una elevada frecuencia de malformaciones. Conclusiones. El resveratrol muestra propiedades antiteratogénicas a través de la disminución del estrés oxidativo que se presenta a causa de la hiperglucemia materna

  19. El aceite de pescado atenua las crisis convulsivas inducidas por hipertermia en ratas neonatas

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    Leopoldo E. Flores M.

    2008-01-01

    Full Text Available Un alto porcentaje (50-60% del cerebro en los mamíferos son principalmente grasas o lípidos, de éstos, el 35% son ácidos grasos esenciales, en particular los llamados omegas (O, como el Acido Docosahexanoico (DHA y el Eicosapentanoico (EPA llamados omega 3 (O-3. Diversos estudios han mostrado beneficios en la salud con la implementación de los O-3 como agentes terapéuticos en alteraciones cardiovasculares, renales, dérmicas, metabólicas, neurodegenerativas e inmunológicas. Evidencias experimentales sugieren un beneficio potencial del aceite de pescado (APE como neuroprotector debido al alto contenido de DHA y EPA. Sin embargo, es poco lo que se conoce en cuanto a los efectos que pudieran tener sobre alteraciones nerviosas, como las crisis convulsivas. En este contexto, se ha reportado que el tipo más común de trastorno epiléptico observado en los niños son las crisis convulsivas provocadas por fiebre (CF. La incidencia es de 3-5%, con ocurrencia entre los 5 meses y 5 años de edad, y se ha propuesto que esta alteración en la vida temprana pudiera tener efectos a largo plazo, manifestándose como un síndrome de epilepsia en la vida adulta. El objetivo del presente estudio fue evaluar el efecto del APE sobre las convulsiones inducidas por hipertermia experimental en un grupo de ratas Wistar macho de 5 días de edad (grupo SAPE cuyas madres consumieron una dieta base más un suplemento de APE (suministrado desde su infancia hasta la etapa de crianza. Este grupo se comparó con otro grupo de ratas de la misma edad y cepa (grupo SAPA cuyas madres consumieron una dieta base más un suplemento de aceite de palma (suministrado desde su infancia hasta la etapa de crianza, y con un tercer grupo de ratas (grupo CTRL cuyas madres consumieron la dieta base más agua bidestilada como suplemento. Las ratas tratadas con APE presentaron mayor resistencia a la elevación de la temperatura corporal inducida por la hipertermia, una menor frecuencia

  20. Estudio anatomopatológico en placentas de mujeres con hipertensión inducida por el embarazo

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    Zamora Vargas, Luis; Aguilar Salazar, Cintya; Cascante Campos, Yancy

    2008-01-01

    La hipertensión inducida por el embarazo (HIE) puede desembocar en una serie de síndromes dependiendo de la gravedad con que se presente y los signos y síntomas que lo acompañen. Sabemos que la interrupción del embarazo junto con la expulsión de la placenta termina con estos problemas. En total se estudiaron 28 placentas en donde los hallazgos más importantes fueron que el 100% de las muestras relacionadas a HIE presentaron patologías y el 87% de las muestras presentaron menos de un 50% de ár...

  1. Efectos del extracto de semillas de uva sobre la cistopatia diabética inducida por estreptozotocina en ratas

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    María Lourdes Arruzazabala

    2010-01-01

    Full Text Available La diabetes por estreptozotocina (STZ en ratas se produce como consecuencia de la necrosis subtotal de los islotes pancreáticos y provoca hiperglicemia, hipoinsulinemia, disminución de la ganancia en peso y aumento del peso de la vejiga, así como hipercontractilidad al carbacol por sobreexpresión de los ARNm-receptores muscarínicos M2 y M3 del detrusor y el urotelio. El extracto de semillas de uva (ESU, rico en flavonoides, ha mostrado efectos antioxidantes y neuroprotectores en modelos experimentales. Por tanto, este estudio investigó si el tratamiento con ESU atenuaba la cistopatía inducida por STZ en ratas. Los animales se distribuyeron en tres grupos: un grupo control no diabético y dos grupos tratados con STZ (50 mg/kg, intraperitoneal. Cuatro semanas después, tanto el grupo control negativo como uno de los tratados con STZ (control positivo recibió el vehículo por vía oral (p.o., mientras el tercer grupo recibió ESU (200 mg/(kg · d, p.o. durante cuatro semanas. Al concluir este período se cuantificó el peso corporal y las concentraciones séricas de glucosa y creatinina. La actividad funcional de la vejiga se investigó usando carbacol (10 -7- 10 -5 mol/L y KCl (100 mmol/L para inducir las contracciones en cada preparación aislada. Las ratas diabéticas por STZ mostraron disminución de la ganancia en peso corporal y aumento de las concentraciones de glucosa y creatinina, así como del peso de las vejigas con relación al grupo control negativo. Las contracciones máximas (Emáx. inducidas por el carbacol en vejigas aisladas fueron significativamente mayores (hiperreactividad en las ratas diabéticas que en los controles negativos. El tratamiento con ESU [200 mg/(kg · d] no modificó la reducción del aumento de peso corporal ni la hiperglicemia en ratas con diabetes inducida por STZ. Además, el ESU no afectó la hiperreactividad al carbacol (E máx. ni la respuesta contráctil del KCl 100 mmol/l de las preparaciones

  2. Determination of forces induced by steam flow in turbines; Determinacion de fuerzas inducidas por flujo de vapor en turbinas

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Castrejon, Juan Carlos

    2008-09-15

    blades, has a harmonic pattern. The pressure field variation as time function is uniform: the peaks and valleys across the axial clearance are always in phase. However the instant picture of the pressure field it's different: the peaks and valleys are not in phase and the number of peaks and valley changed across the clearance. In the case of the forces acting on blades, a Fourier on the forces calculated was used to determine the coefficients and frequency of a Fourier equation which can be used to calculate the alternating stresses on the blade in order to predict the useful life blades. [Spanish] Las vibraciones inducidas por flujo de vapor en turbinas representan uno de los problemas que enfrenta la operacion de turbinas de vapor cuya capacidad rebasa los 300 MW. Ademas estas constituyen uno de los limites tecnologicos para el desarrollo de turbinas de vapor de mas de 1 GW. Este tipo de fenomeno tiene su origen en la interaccion del rotor con el fluido que se encuentra en sus proximidades. El flujo de vapor dentro de la turbina es complejo, ya que es turbulento e inestable. A medida que el flujo pasa una etapa de estator o de rotor, se generan secundarios, vortices en los filos de salida, estelas con caracteristicas de flujo diferentes al flujo principal en los pasajes. Estas variaciones en el flujo son las que inducen vibraciones forzadas en los alabes. Ademas existen varios factores que contribuyen a la aplicacion de vibraciones en alabes inducidas por flujo como son: inestabilidad del flujo de vapor en los claros de los sellos, secuencia de apertura de las valvulas, estelas de las toberas, obstrucciones en algunas de las toberas y diferente espaciamiento en las toberas. Las vibraciones por flujo pueden ser peligrosas si su frecuencia coincide con la frecuencia natural del sistema, provocando efectos mas nocivos que las vibraciones por desbalance o por desalineamiento, pues tienen amplitudes mas grandes y provocan esfuerzos alternantes en los componentes del

  3. Efectividad de la ivermectina en un modelo de disquinesia tardía inducida por haloperidol en ratas

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    Mauricio Palacios

    2008-09-01

    Full Text Available Introducción: Los síntomas extrapiramidales y en especial las disquinesias tardías, son la mayor limitante de la terapia con antipsicóticos, debido a la frecuencia de aparición durante el tratamiento y la falta de recursos para controlar estas reacciones adversas, por lo cual es necesario investigar nuevos recursos para el manejo de las disquinesias tardías.Objetivo: Evaluar el efecto de la ivermectina sobre las disquinesias tardías inducidas por haloperidol en ratas.Métodos: En un modelo de dosis única de haloperidol con ratas Sprague Dawley, se evalúo la capacidad de la ivermectina para evitar cambios en la conducta motora y la aparición de movimientos anormales. Adicionalmente, se implementó un modelo animal crónico conocido como VCM (vacuous chewing movements, donde se evaluó la frecuencia de movimientos orofaciales durante seis meses, al recibir simultáneamente haloperidol e ivermectina a dosis diferentes, comparándolo con un grupo control y otro grupo al que se le administró haloperidol.Resultados: La ivermectina no evitó los cambios inducidos por haloperidol en el comportamiento motor, ni la aparición de movimientos anormales en el modelo agudo. Tampoco modificó la frecuencia de movimientos orofaciales en el modelo de administración crónica de haloperidol. La ivermectina no indujo cambios en la conducta motora, ni la aparición de movimientos anormales en los modelos agudo y crónico.Conclusiones: Los hallazgos de este trabajo descartan a la ivermectina como candidata para el manejo de las disquinesias tardías y no permite aportar argumentos a la hipótesis GABAérgica en la fisiopatología de las disquinesias tardías. Adicionalmente, la ivermectina no induce movimientos anormales.

  4. Arteriopatía periférica crónica inducida por cocaína

    Directory of Open Access Journals (Sweden)

    Sonia Pankl

    2012-02-01

    Full Text Available La trombosis periférica aguda inducida por cocaína ha sido descripta en la literatura, siendo una complicación poco común. Si bien existen comunicaciones que reflejan los efectos crónicos de la cocaína sobre el sistema arterial periférico, no hay casos publicados de tal complicación en ausencia de otros factores de riesgo. Se presenta el caso de una mujer de 22 años de edad con antecedentes de consumo de cocaína intranasal de 3 gramos por semana durante un año, que consultó por claudicación intermitente a los 200 metros asociada a dolor y parestesias en miembro inferior izquierdo de 2 meses de evolución. El ecodoppler arterial evidenció una estenosis mayor del 70% en la arteria femoral superficial izquierda. Se realizaron estudios complementarios descartando otras etiologías probables. Se inició tratamiento con ácido acetilsalicílico, cilostazol y ejercicio reglado, asociado a terapia de apoyo para mantenimiento del cese del consumo de cocaína, con buena respuesta. Se destaca la importancia de la difusión de información a los pacientes, dado que la mayoría de la población desconoce las complicaciones cardiovasculares de dicha adicción. Es indispensable indagar sobre el consumo de cocaína en pacientes jóvenes con arteriopatía sin factores de riesgo aparentes.

  5. Desensibilización inducida por agonista del receptor TRPV1

    OpenAIRE

    2014-01-01

    El receptor TRPV1 es un canal catiónico capaz de activarse por calor, pH ácido, voltaje y por diferentes sustancias químicas entre las que destacan los agonistas vanilloides capsaicina y resiniferatoxina. En las neuronas aferentes nociceptivas o nociceptores, donde se expresa de forma abundante, TRPV1 actúa como un sensor polimodal cuya actividad se controla por multitud de mecanismos reguladores capaces de causar su sensibilización o desensibilización. La estimulación prolongada por sus agon...

  6. DT-DIAFORASA IMPIDE LA FORMACION DE OLIGOMEROS DE ALFA-SINUCLEINA INDUCIDA POR AMINOCROMO.

    OpenAIRE

    CARDENAS MUÑOZ, SERGIO PATRICIO

    2008-01-01

    La agregación de ct-sinucleína se ha relacionado por varios autores con la enfermedad de parkinson. Recientemente, se ha evidenciado por estudios in vitro que la dopamina al oxidarse induce la agregación de a-sinucleína a estructuras protofibrilares neuro 120p.

  7. Respuestas de defensa inducidas por Acibenzolar-S-Metil (ASM) en plantas de uchuva (Physalis peruviana)

    OpenAIRE

    Carvajal Arias, Carel Elizabeth

    2013-01-01

    Colombia es uno de los principales países productores de uchuva para exportación, llegando a ocupar el primer lugar como el mayor productor seguido por Sudáfrica. El fruto producido en Colombia (ecotipo Colombia) es uno de los más apetecidos por el mercado internacional, debido a sus características organolépticas y alto contenido de azúcar y vitaminas (Puente et al. 2011). Durante su desarrollo el cultivo puede ser afectado por diferentes plagas y enfermedades, dentro de las cuales se encuen...

  8. Detección y estudio mediante Fluorescencia Inducida por Láser de radicales libres formados por Disociación Multifotónica Infrarroja

    Science.gov (United States)

    Santos, M.; Díaz, L.; Torresano, J. A.; Rubio, L.; Samoudi, B.

    Una de las principales aplicaciones actuales de los procesos de disociación multifotónica inducidos por radiación láser infrarroja (DMI) es la producción de radiales libres, con el fin de estudiar sus propiedades cinéticas y espectroscópicas. La disociación de moléculas poliatómicas en el IR con láseres de CO2 tiene lugar desde la superficie de energía molecular mas baja y conduce generalmente a la formación de fragmentos en el estado electrónico fundamental, con diversos grados de excitación vibracional. En el Grupo de Procesos Multifotónicos del Instituto de Estructura de la Materia del C.S.I.C. hemos puesto a punto la técnica de Fluorescencia Inducida por Láser (LIF) para la detección y análisis en tiempo real de los fragmentos producidos en la DMI inducida mediante uno o dos campos láseres de diferentes longitudes de onda. Objetivos de nuestro trabajo han sido el estudio de los canales de disociación mayoritarios y de las especies transitoria producidas, así como de la distribución de energía interna con que éstas son generadas. En particular hemos detectado mediante LIF las especies: C2, CF, CH, SiH2, CF2, CH2, SiHCl, y CF3 a partir de la disociación de, entre otras, las siguientes moléculas: C2H3Br, C3F6, C4H8Si, C2H5ClSi y CH5ClSi. En este trabajo presentamos algunos de los resultados obtenidos mediante el estudio por LIF de estos radicales: estudio temporal de la señal LIF obtenida con determinación de tiempos de vida, espectros de excitación y fluorescencia, temperaturas vibracionales de formación, variación de la intensidad LIF con el tiempo de retraso entre los láseres de disociación y prueba, etc.

  9. Vigilancia ocupacional del trabajador expuesto a alteraciones de la salud inducidas por ruido

    Directory of Open Access Journals (Sweden)

    Julio C. Guerrero Pupo

    2005-01-01

    Full Text Available Aborda un estudio donde se analiza que la sustentabilidad terrícola está en peligro por los problemas ambientales presentes, destacando, a nivel local el ruido. Señala que es "causa" de alteraciones a la salud en ciertos puestos de trabajo y que el proceso se puede esquematizar como un eje constituido por factor de riesgo-exposición -efecto. Argumenta que empleó el método epidemiológico. Plantea la vigilancia epidemiológica hombre - ambiente y los efectos auditivos y no auditivos inducidos por ruido. Concluye que el Estado anhela su control y que su mejor representante es el médico de la familia al formarse integralmente en varias disciplinas.

  10. MECANISMOS MOLECULARES DE LA AUTOFAGIA INDUCIDA POR AGONISTAS β-ADRENERGICOS EN EL FIBROBLASTO CARDIACO

    OpenAIRE

    ARANGUIZ URROZ, PABLO DANIEL; ARANGUIZ URROZ; PABLO DANIEL

    2012-01-01

    En el corazón, la homogeneidad estructural y funcional está gobernada por la existencia de un equilibrado balance entre señales reguladoras del crecimiento, proliferación y muerte de sus células, y del recambio de las proteínas de la matriz extracelular (MEC). En diversas patologías cardiacas se desarrolla un proceso conocido como remodelado del miocardio (RM), caracterizado por un elevado depósito de proteínas de la MEC que conduce a fibrosis cardiaca. En este sentido, hay numerosas evide...

  11. CARACTERIZACION DE LAS RESPUESTAS BIOLOGICAS INDUCIDAS POR EL PLASMA RICO EN PLAQUETAS DURANTE LA REPARACION TISULAR

    OpenAIRE

    CACERES LLUCH, MONICA ANDREA

    2011-01-01

    Se ha propuesto el empleo de factores solubles derivados de plaquetas con el objeto de promover la reparación de tejidos. A pesar que diversos estudios han evaluado la respuesta de células gingivales y periodontales a fracciones derivadas de plaquetas, existe un fuerte debate acerca de los efectos ejercidos por estos factores sobre respuestas celulares relacionadas con la reparación tisular. En la presente tesis hemos evaluado la respuesta de cultivos primarios de fibroblastos gingiv...

  12. Intervenci??n multimodal en la fatiga inducida por el c??ncer de mama mediante un programa de fisioterapia y ejercicio f??sico

    OpenAIRE

    Cantarero Villanueva, Irene

    2011-01-01

    La supervivencia a un c??ncer de mama se ha incrementado cuantiosamente en estos a??os. Estas mujeres arrastran numerosas secuelas, entre las que destaca la fatiga, un s??ntoma de naturaleza multifactorial que merma su calidad de vida. Con esta memoria de Tesis se persigui?? mejorar la comprensi??n sobre la fatiga inducida por el c??ncer de mama estudiando su relaci??n con distintos factores, as?? como analizar la efectividad de un programa multimodal de ejercicio terap??utico. Las 95 p...

  13. Intervención multimodal en la fatiga inducida por el cáncer de mama mediante un programa de fisioterapia y ejercicio físico

    OpenAIRE

    Cantarero Villanueva, Irene

    2013-01-01

    La supervivencia a un cáncer de mama se ha incrementado cuantiosamente en estos años. Estas mujeres arrastran numerosas secuelas, entre las que destaca la fatiga, un síntoma de naturaleza multifactorial quemerma su calidad de vida. Con esta memoria de Tesis se persiguió mejorar la comprensión sobre la fatiga inducida por el cáncer de mama estudiando su relación con distintos factores, así como analizar la efectividad de un programa multimodal de ejercicio terapéutico.Las 95 participantes habí...

  14. EFECTO DE GENTIANELLA ALBOROSEA EN ESTEATOSIS HEPÁTICA NO ALCOHÓLICA INDUCIDA POR DIETA HIPERLIPÍDICA EN RATAS HOLTZMAN HEMBRAS

    OpenAIRE

    L Ugaz-Soto; JH Zafra-Tanaka; María E. Tapia Vicente

    2012-01-01

    Objetivo: Determinar el efecto del extracto de Gentianella alborosea como tratamiento contra esteatosis hepática no alcohólica (EHNA)  inducida por dieta hiperlipídica en ratas Holtzman hembras. Métodos: Diseño: Estudio experimental incompleto. Lugar: Universidad Nacional Mayor de San Marcos, Lima, Perú. Participantes: Ratas Holtzman hembras. Intervenciones: Se utilizó 32 ratas repartidas en 4 grupos (n=8) distribuidos aleatoriamente: grupo control negativo, control positivo con dieta hiperli...

  15. Etilefrina en hipotensión inducida por anestesia raquídea en cesárea. Hospital María Auxiliadora 2015

    OpenAIRE

    Ramos Pahuachon, Jenny Rocio

    2015-01-01

    Introducción: La hipotensión arterial materna es el efecto adverso más prevalente luego de la anestesia regional raquídea .El objetivo principal del estudio es identificar si la etilefrina es un fármaco adecuado para el tratamiento de la hipotensión inducida por anestesia regional raquídea. Material y métodos: Estudio retrospectivo de investigación de datos y efectos adversos de 70 pacientes sometidas a cesáreas electivas con anestesia regional raquídea utilizándose etilefrina en el tratam...

  16. EFECTO DE LA BEBIDA GASIFICADA EN LA PARED GÁSTRICA DE RATAS MACHO CON GASTRITIS INDUCIDA POR ÁCIDO ACETILSALICÍLICO

    OpenAIRE

    Alejandro Martinez; Katia Bravo; Saúl Gonzales; Diana Lecca; Melissa Mendoza; Melissa Paragua; Isabel Pinedo; Luis Ramos; Miriam Salcedo; Diana Torpoco; Yao-Te Wang; Ernesto Ráez

    2011-01-01

    Objetivo: Evaluar el efecto del consumo prolongado de una bebida gasificada sobre la pared gástrica de ratas con gastritis inducida por ácido acetilsalicílico. Métodos: Estudio experimental Participantes: ratas macho de 3,5 meses de edad Intervenciones: Se indujo gastritis mediante la administración oral diaria de 300 mg/kg de ácido acetilsalicílico, en solución con agua (grupo control) o bebida gasificada (grupo experimental). Luego de tres semanas se evaluaron las alteraciones histopatoló...

  17. Papel antioxidante de la vitamina E en la aterogénesis inducida por hiperfibrinogenemia

    Directory of Open Access Journals (Sweden)

    Mónica Moya

    2010-01-01

    Full Text Available Con el propósito de estudiar el efecto de la vitamina E sobre el estrés oxidativo desencade- nado por hiperfibrinogenemia (HF en un modelo experimental de aterogénesis y la posible normalización de los indicadores de estrés oxidativo, se evaluaron: óxido nítrico (NO, L-citrulina, superóxido dismutasa (SOD e involución de lesiones histopatológicas en la aorta torácica. El estudio se realizó en 36 ratas, cepa Wistar, que se dividieron en tres grupos (n = 12 cada uno: A, control; B, HF × 90 días; C, HF × 90 días + vitamina E. La HF se indujo mediante inyecciones de adrenalina (0,1 ml/día/rata por 90 días. La dosis de vitamina E fue de 2 mg/día/rata durante 75 días. Se dosaron en plasma los niveles de fibrinógeno (mg/dl, NO (uM y L-citrulina (mM y en lisado de glóbulos rojos, por espectrofotometría, se determinó la actividad de la SOD (U/ml. Se analizaron cortes de la aorta torácica por microscopia óptica (MO. Para el análisis estadístico se emplearon MANOVA y la prueba de Fisher; se estableció un nivel de significación de p < 0,05. Se observó un aumento significativo de fibrinógeno en el grupo B (407 ± 8,9 mg/dl en comparación con los grupos A (203 ± 9 mg/dl y C (191,58 ± 17,79 mg/dl (p < 0,001. El NO disminuyó significativamente en el grupo B (13,73 ± 1,76 uM frente a los grupos A (23,58 ± 0,08 uM y C (26,64 ± 3,65 uM (p < 0,001. La L-citrulina aumentó en forma significativa en los grupos B (4,99 ± 0,18 mM y C (6,60 ± 0,16 mM en comparación con el grupo A (3,03 ± 0,13 mM (p < 0,001. El SOD incrementó su actividad en los grupos B (251,67 ± 10,34 U/ml y C (304,75 ± 10,43 U/ml frente al grupo A (139,44 ± 4,74 U/ml (p < 0,001. La microscopia óptica mostró denudación endotelial, engrosamiento intimal y protrusión de la pared en el grupo B (90% y recuperación de la denudación endotelial y disminución del 50% del engrosamiento intimal en el grupo C (p < 0,001. Niveles aumentados de SOD ser

  18. Mecanismos patogénicos de las lesiones gastrointestinales inducidas por meloxicam y piroxicam.

    OpenAIRE

    Villegas Lama, Isabel

    2001-01-01

    Falta Palabras clave Los antiinflamatorios no esteroides (AINE) se encuentran entre los fármacos más consumidos en todo el mundo. Su amplia utilización está avalada por sus propiedades analgésicas, antiinflamatorias y antipiréticas. Sin embargo, el uso de estos fármacos se acompaña de efectos secundarios, que pueden aparecer hasta en el 25% de los pacientes, siendo los relacionados con el tracto digestivo un número importante. Se ha descrito todo un abanico de reacciones adversas a este ni...

  19. CONTRIBUCION DEL CANAL TIPO TASK A LA HIPERREACTIVIDAD DEL CUERPO CAROTIDEO INDUCIDA POR HIPOXIA INTERMITENTE CRONICA

    OpenAIRE

    ORTIZ CISTERNAS; FERNANDO ANDRES

    2011-01-01

    El cuerpo carotídeo (CC) es el principal órgano quimiosensorial periférico que detecta los cambios en los niveles arteriales de P02, PC02 y pH. En respuesta a la hipoxia aguda las células quimiorreceptoras (tipo 1) del ce se despolarizan gatillando un aumento del ci+ intracelular y la concomitante liberación de uno o más neurotransmisores. Se ha propuesto que -al menos en ratas neonatas- esta despolarización se inicia con la inhibición por hipoxia de una corriente de K+ de...

  20. Epitelización inducida por células troncales derivadas del tejido adiposo

    Directory of Open Access Journals (Sweden)

    M. Meruane

    2014-06-01

    Full Text Available El tratamiento de lesiones con pérdida de tejido cutáneo ha mejorado notablemente con el advenimiento de la bioingeniería tisular. Una alternativa en desarrollo es la utilización de sustitutos dérmicos combinados con células troncales derivadas del tejido adiposo autólogo. Estudios previos nos muestran que con esta técnica es posible optimizar la angiogénesis y la síntesis de colágeno, sin embargo potenciar la epitelización es un tema pendiente por resolver. En el presente estudio evaluamos la progresión y diferenciación epitelial en un período de tiempo prologando. Obtuvimos las células troncales a partir del tejido adiposo (ASC de la región inguinal de 4 ratas Sprague Dawley. Cultivamos las células frescas en una matriz de Integra® durante un período total de 48 horas, y las marcamos con un vector lentiviral-GFP (proteína fluorescente verde. Posteriormente, injertamos en las mismas ratas la matriz dérmica con células troncales y un implante contralateral sin células, como control. A las 4 semanas, evaluamos el avance epitelial mediante planimetría de superficie e histología. Los resultados macroscópicos muestran que el cierre de la herida por contracción de los bordes no tiene diferencias significativas (82,63% ± 3,4% vs. 80,66% ± 3,89%; p=0,08, pero el cierre por epitelización fue significativamente mayor en el lado intervenido con ASCs (93,47% ± 5,98% vs. 79,88% ± 6,28%; p=0,0028. Todas las muestras obtuvieron tinción positiva para el anticuerpo anti-citoqueratina 34βE12 y el avance epitelial lineal cuantificado por microscopía resultó significativamente mayor en el lado con ASCs (6408 ± 275μm vs. 5375 ± 250μm; p < 0,001. Identificamos las células GFP positivas formando parte de la dermis regenerada, no así en la epidermis. En conclusión, las células troncales derivadas del tejido adiposo autólogo sembradas en una matriz de Integra® aumentan la formación epitelial significativamente

  1. EFECTO DEL DIMETILSULFÓXIDO EN UN MODELO ANIMAL DE NEFROTOXICIDAD INDUCIDA POR GENTAMICINA EN CONEJOS

    Directory of Open Access Journals (Sweden)

    Oscar Francisco López Núñez

    2013-07-01

    Full Text Available Objetivo: La utilidad clínica de la gentamicina se ve limitada por sus efectos deletéreos renales, causados principalmente por daño oxidativo. Dado que el dimetilsulfóxido posee propiedades antioxidantes, se plantea su uso como agente nefroprotector en un modelo animal. Métodos: Se distribuyeron de forma aleatoria 24 conejos en 3 grupos (A, B y C, se administró durante 5 días solución salina normal 0,9%(SSN para el grupo A, gentamicina más SSN para el grupo B y gentamicina más dimetilsulfóxido al 25% para el grupo C. Se determinaron los parámetros: creatinina sérica, actividad enzimática (n-acetyl-b-d-glucosaminidasa urinaria e histopatología renal. Resultados: La creatinina aumentó respecto al valor basal en los grupos B y C (p=0,009. La comparación del incremento entre grupo A vs C mostró significancia estadística (p=0,0194. La clasificación para lesión renal aguda RIFLE fue del 25% y 50% en estadío Riesgo para los grupos C y B respectivamente y 12,5% en estadío Injuria para el grupo B. La actividad de n-acetyl-b-d-glucosaminidasa urinaria presentó incrementos en todas sus mediciones (p<0,05. La histopatología reveló necrosis mayor del 50% de los túbulos proximales en el 25% del grupo C y 87,5% del grupo B, así como necrosis total en 12,5% del grupo B. Se observaron diferencias entre el grupo A vs B (p<0,001 y C (p<0,05. Conclusiones: El modelo planteado induce nefrotoxicidad. El uso de dimetilsulfóxido no redujo el incremento en los niveles de creatinina y en actividad enzimática, mientras que la Lesión Renal Aguda (LRA por evaluación histopatológica presentó una leve mejoría que carece de respaldo estadístico. Palabras Clave: Dimetilsulfóxido, gentamicina, lesión renal aguda, radicales libres

  2. EFECTO DEL DIMETILSULFÓXIDO EN UN MODELO ANIMAL DE NEFROTOXICIDAD INDUCIDA POR GENTAMICINA EN CONEJOS

    Directory of Open Access Journals (Sweden)

    Oscar Francisco López Núñez

    2013-01-01

    Full Text Available Objetivo: La utilidad clínica de la gentamicina se ve limitada por sus efectos deletéreos renales, causados principalmente por daño oxidativo. Dado que el dimetilsulfóxido posee propiedades antioxidantes, se plantea su uso como agente nefroprotector en un modelo animal. Métodos: Se distribuyeron de forma aleatoria 24 conejos en 3 grupos (A, B y C, se administró durante 5 días solución salina normal 0,9%(SSN para el grupo A, gentamicina más SSN par el grupo B y gentamicina más dimetilsulfóxido al 25% para el grupo C. Se determinaron los parámetros: creatinina sérica, actividad enzimática (n-acetyl-b-d-glucosaminidasa urinaria e histopatología renal. Resultados: La creatinina aumentó respecto al valor basal en los grupos B y C (p=0,009. La comparación del incremento entre grupo A vs C mostró significancia estadística (p=0,0194. La clasifica- ción para lesión renal aguda RIFLE fue del 25% y 50% en estadío Riesgo para los grupos C y B respectivamente y 12,5% en estadío Injuria para el grupo B. La actividad de n-acetyl-b-d-glucosaminidasa urinaria presentó incrementos en todas sus mediciones (p<0,05. La histopatología reveló necrosis mayor del 50% de los túbulos proximales en el 25% del grupo C y 87,5% del grupo B, así como necrosis total en 12,5% del grupo B. Se observaron diferencias entre el grupo A vs B (p<0,001 y C (p<0,05. Conclusiones: El modelo planteado induce nefrotoxicidad. El uso de dimetilsulfóxido no redujo el incremento en los niveles de creatinina y en actividad enzimática, mientras que la Lesión Renal Aguda (LRA por evaluación histopatológica presentó una leve mejoría que carece de respaldo estadístico.

  3. EFECTO PROTECTOR DE PEUMUS BOLDUS EN RATAS CON TOXICIDAD HEPÁTICA INDUCIDA POR PARACETAMOL

    Directory of Open Access Journals (Sweden)

    Christiam Ochoa

    2012-02-01

    Full Text Available Objetivo: Comprobar el efecto protector hepático del extracto acuoso de boldo (EAB (Peumus boldus al daño hepático inducido por acetaminofén (paracetamol. Diseño: Analítico, experimental, aleatorizado, completo – experimento verdadero. Realizado en el Instituto de Patología de la Facultad de Medicina de UNMSM. Material y método. 30 Ratas Holtzman macho de 250g y dos meses se dividieron en 5 grupos aleatoriamente, grupo blanco, control paracetamol 200mg/kg y 3 experimentales tratados con EAB a 80 mg/kg, 120 mg/kg y 160 mg/kg respectivamente. Se administró EAB de 80 mg/kg, 120 mg/kg y 160 mg/kg vía orogástrica. Luego de media hora se administró paracetamol 200mg/kg i.p. a los grupos control y experimentales. Este procedimiento se repitió por 5 días. Se tomó pruebas de transaminasas (TGP basal y final en sangre. Se utilizó la prueba de Kruskal-Wallis para analizar la data y un p<0.05 fue considerado significante. Se estudió la anatomopatología de los hígados y se tomaron muestras de tejido teñidas con HE. Resultados: Existe diferencia significativa en los niveles de transaminasas (TGP entre grupos (p<0.05. El control obtuvo 196.6 U/L +- 38.1 (TGP mientras que los experimentales como máximo 55.6 U/l. Las muestras control evidencian signos de lesión hepática, degeneración grasa, congestión sinusoidal y centrolobulillar, y necrosis celular. Sin embargo los grupos experimentales no presentan signos de lesión celular y hay ausencia de inflamación. Conclusiones: El boldo tiene un efecto protector hepático al daño inducido por paracetamol en ratas Holtzmann.

  4. Efecto Protector de Peumus Boldus en ratas con toxicidad hepática inducida por Paracetamol

    Directory of Open Access Journals (Sweden)

    Christiam Ochoa

    2008-01-01

    Full Text Available Objetivo: Comprobar el efecto protector hepático del extracto acuoso de boldo (EAB (Peumus boldus al daño hepático inducido por acetaminofén (paracetamol. Diseño: Analítico, experimental, aleatorizado, completo ¿ experimento verdadero. Realizado en el Instituto de Patología de la Facultad de Medicina de UNMSM. Material y método. 30 Ratas Holtzman macho de 250g y dos meses se dividieron en 5 grupos aleatoriamente, grupo blanco, control paracetamol 200mg/kg y 3 experimentales tratados con EAB a 80 mg/kg, 120 mg/kg y 160 mg/kg respectivamente. Se administró EAB de 80 mg/kg, 120 mg/kg y 160 mg/kg vía orogástrica. Luego de media hora se administró paracetamol 200mg/kg i.p. a los grupos control y experimentales. Este procedimiento se repitió por 5 días. Se tomó pruebas de transaminasas (TGP basal y final en sangre. Se utilizó la prueba de Kruskal-Wallis para analizar la data y un p<0.05 fue considerado significante. Se estudió la anatomopatología de los hígados y se tomaron muestras de tejido teñidas con HE. Resultados: Existe diferencia significativa en los niveles de transaminasas (TGP entre grupos (p<0.05. El control obtuvo 196.6 U/L +- 38.1 (TGP mientras que los experimentales como máximo 55.6 U/l. Las muestras control evidencian signos de lesión hepática, degeneración grasa, congestión sinusoidal y centrolobulillar, y necrosis celular. Sin embargo los grupos experimentales no presentan signos de lesión celular y hay ausencia de inflamación. Conclusiones: El boldo tiene un efecto protector hepático al daño inducido por paracetamol en ratas Holtzmann.

  5. Frecuencia de Hipertensión arterial inducida por el embarazo en derechohabientes de una Unidad de Medicina Familiar de Ciudad Obregón, Sonora (México)

    OpenAIRE

    MP Pérez Juárez; O Castañeda-Sánchez; V. Arellano-Cuadros; J. Espinoza-Suárez

    2008-01-01

    Objetivo: Determinar la frecuencia de hipertensión arterial inducida por el embarazo en derechohabientes de la Unidad de Medicina Familiar (UMF) No. 1 de ciudad Obregón, Sonora (México) durante 2003. Material y métodos: Se realizó un estudio transversal descriptivo. Se analizó el informe de consulta externa del servicio de obstetricia (formato 430-6) en el Hospital de Especialidades No 1; se identificaron casos consecutivos de pacientes con hipertensión arterial inducida por embarazo (HIE). V...

  6. XANTATINA INHIBE LA ACTIVACIÓN DE MASTOCITOS INDUCIDA POR NEUROPÉPTIDOS PRO-INFLAMATORIOS. XANTHATIN INHIBITS MAST CELL ACTIVATION INDUCED BY PRO-INFLAMMATORY NEUROPEPTIDES

    Directory of Open Access Journals (Sweden)

    Carlos E Tonn

    2010-03-01

    Full Text Available Mast cells are connective tissue cells involved in the genesis and modulation of inflammatory responses. We have previously shown that xanthatin (xanthanolide sesquiterpene isolated from Xanthium cavanillesii Schouw inhibits mast cell activation induced by experimental secretagogues. However, the effect of xanthatin on mast cell activation induced by pathophysiological stimuli remains unknown. These stimuli include, among others, the pro-inflammatory neuropeptide substance P and neurotensin, responsible for one of the main pathways of neurogenic inflammation. The present study was designed to examine the effects of xanthatin on mast cell activation induced by pro-inflammatory peptides, such as substance P and neurotensin. Rat peritoneal mast cells were incubated with: 1 PBS (basal; 2 substance P (100 µm; 3 neurotensin (50 µm; 4 xanthatin (8-320 µm+substance P; 5 xanthatin (8-320 µm+neurotensin. Concentration-response studies of mast cell serotonin release evoked by pro-inflammatory neuropeptides, evaluation of mast cell viability and morphology by light and electron microscopy, and drug stability analysis by thin layer chromatography were performed. Serotonin release studies, carried out together with morphological studies, showed the effectiveness of xanthatin to stabilize mast cells. The present study provides the first strong evidence in favour of the hypothesis that xanthatin inhibits substance P - and neurotensin-induced serotonin release from peritoneal mast cells. Our findings may provide an insight into the design of novel pharmacological agents which may be used to regulate the mast cell response in neurogenic inflammation.Los mastocitos son células del tejido conectivo que participan en la génesis y modulación de las respuestas inflamatorias. Previamente hemos demos-trado que xanthatina (xanthanólido sesquiterpeno aislado de Xanthium cavanillesii Schouw inhibe la activación de mastocitos inducida por secretagogos

  7. Protección inducida por nanococleatos derivados de proteoliposomas de Leptospira interrogans serovar Canicola

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    Beatriz Tamargo

    2012-04-01

    Full Text Available Desde los años 20 del pasado siglo, hasta el presente, en el mundo se han desarrollado y empleado vacunas de células enteras contra la leptospirosis que confieren una corta inmunidad; la mayoría no adyuvadas y dirigidas, fundamentalmente, contra los diferentes serogrupos de la especie Leptospira interrogans, contenidos en las preparaciones. Numerosos han sido los intentos realizados para lograr una formulación vacunal más pura, efectiva, de amplio espectro y duración de la protección que las bacterinas de células enteras inactivadas. Sin embargo, hasta el momento no se ha registrado ninguna vacuna con tales características. En el presente trabajo se obtuvieron antígenos de membrana externa a partir de una cepa cubana autóctona (Cepa 87, L. interrogans serovar Canicola, mediante una modificación de la tecnología para la producción de vesículas de membrana, patentada por investigadores del Instituto Finlay. Estos antígenos con estructura nanoproteoliposómica fueron formulados/adyuvados mediante diferentes estrategias, logrando cinco preparaciones con estructura coclear, que constituyen nanopartículas de aproximadamente 100 a 150 nm de largo y entre 15 a 30 nm de diámetro. Los inmunógenos se inocularon en el biomodelo Mesocrisetus aureatus, con dos dosis e intervalo de seis semanas. El reto fue realizado con 100.000 DL 50 . Los resultados demuestran que las nuevas formulaciones vacunales confieren protección frente al reto homólogo y fueron capaces de eliminar el estado de portador, lo que unido a la robustez del método de preparación, el mayor nivel de pureza, en comparación con las bacterinas, y la no necesidad del hidróxido de aluminio, las convierten en una alternativa de interés para continuar su desarrollo.

  8. EFECTO DE LA BEBIDA GASIFICADA EN LA PARED GÁSTRICA DE RATAS MACHO CON GASTRITIS INDUCIDA POR ÁCIDO ACETILSALICÍLICO

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    Alejandro Martinez

    2011-01-01

    Full Text Available Objetivo: Evaluar el efecto del consumo prolongado de una bebida gasificada sobre la pared gástrica de ratas con gastritis inducida por ácido acetilsalicílico. Métodos: Estudio experimental Participantes: ratas macho de 3,5 meses de edad Intervenciones: Se indujo gastritis mediante la administración oral diaria de 300 mg/kg de ácido acetilsalicílico, en solución con agua (grupo control o bebida gasificada (grupo experimental. Luego de tres semanas se evaluaron las alteraciones histopatológicas sobre la pared gástrica. Principales resultados: Se utilizó la Puntuación de Lapa modificada para el análisis macroscópico, comparándose los resultados mediante la Prueba U de Mann-Whitney (p<0,05. Se midió la profundidad de las lesiones microscópicamente, analizándose los resultados con la Prueba T de Student bilateral (p<0,05. Resultados: En ambos casos, las diferencias fueron estadísticamente significativas (p=0,009 y p<0,001, respectivamente, encontrándose lesiones de mayor magnitud en el grupo experimental. Conclusiones: El consumo prolongado de bebida gasificada tiene un efecto agravante del daño producido en la pared gástrica de ratas con gastritis inducida por ácido acetilsalicílico.

  9. Efecto de la bebida gasificada en la pared gástrica de ratas macho con gastritis inducida por ácido acetilsalicílico

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    Alejandro Martinez

    2012-09-01

    Full Text Available Objetivo: Evaluar el efecto del consumo prolongado de una bebida gasificada sobre la pared gástrica de ratas con gastritis inducida por ácido acetilsalicílico. Diseño: Estudio experimental  Participantes: ratas macho de 3,5 meses de edad Intervenciones: Se indujo gastritis mediante la administración oral diaria de 300 mg/kg de ácido acetilsalicílico, en solución con agua (grupo control o bebida gasificada (grupo experimental. Luego de tres semanas se evaluaron las alteraciones histopatológicas sobre la pared gástrica. Principales resultados: Se utilizó la Puntuación de Lapa modificada para el análisis macroscópico, comparándose los resultados mediante la Prueba U de Mann-Whitney (p<0,05. Se midió la profundidad de las lesiones microscópicamente, analizándose los resultados con la Prueba T de Student bilateral (p<0,05. Resultados: En ambos casos, las diferencias fueron estadísticamente significativas (p=0,009 y p<0,001, respectivamente, encontrándose lesiones de mayor magnitud en el grupo experimental. Conclusiones: El consumo prolongado de bebida gasificada tiene un efecto agravante del daño producido en la pared gástrica de ratas con gastritis inducida por ácido acetilsalicílico.

  10. Propagación de la transformación martensítica inducida por deformación en la velocidad de crecimiento de grietas por fatiga de aceros inoxidables austeníticos metaestables

    OpenAIRE

    Rodríguez Nogal, Javier

    2007-01-01

    En este proyecto se ha realizado una introducción a los aceros inoxidables, su uso, aplicación y breve historia de su origen. A continuación se ha estudiado en detalle la transformación martensítica inducida por deformación en los aceros inoxidables austeníticos metaestables, por ser este tipo de inoxidables los analizados en el proyecto. Se ha realizado la caracterización microestructural de un redondo de acero inoxidable austenítico metaestable calidad AISI 301, así como una ...

  11. Modelo animal de anemia inducida por flebotomía crónica: Relación funcional entre hierro y eritropoyesis

    OpenAIRE

    Prieto Suani, Gaona; Villarraga Muñoz, María del Mar; D´, Anna Maria; Giorgi, Gisela; Garcia, Betina; Mora Bautista, Ana Isabel; Castillo Bohórquez, Martha; Roque, Marta E

    2012-01-01

    En el presente estudio se analizo la respuesta eritropoyética a la anemia inducida por flebotomía crónica y los cambios en la distribución del hierro celular y sistémico del organismo. Ratones hembra de la cepa CF1 (n=32), se dividieron en dos lotes: control y experimental, siguiendo un diseño experimental pareado según su peso. La distribución del hierro en bazo e hígado durante la flebotomía crónica fue evaluada mediante estudios morfológicos y la actividad eritropoyética mediante estudios ...

  12. El tratamiento con progesterona previene las alteraciones motoras inducidas por la intoxicación con semillas de cícada (Dioon spinulosum en la rata macho

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    E Rivadeneyra-Domínguez

    2009-01-01

    Full Text Available El consumo crónico de semillas de cícadas ha sido asociado con enfermedades neurodegenerativas, las cuales predominan en el género masculino. En México, las semillas de cícada (Dioon spinulosum son usadas como sustituto de maíz y a nivel experimental producen un déficit motor; probablemente causado por sus componentes neurotóxicos. En este sentido, la progesterona ejerce efectos neuroprotectores contra traumatismo cerebral, hipoxia, así como la muerte neuronal inducida por colchicina en el SNC; por lo que podría prevenir los efectos neurotóxicos producidos por el consumo crónico de semillas de Dioon spinulosum en ratas, una posibilidad explorada en el presente estudio. Se emplearon 32 ratas macho de la cepa Wistar distribuidas en cuatro grupos: a un grupo control recibió 1 ml de agua purificada(v.o. y 0,2 ml de aceite de maíz (s.c.; b un grupo cícada recibió 5 g/kg de la semilla de cícada (v.o. y 0,2 ml de aceite de maíz (s.c.; cun grupo más recibió 1 ml de agua purificada (v.o. y 3 mg/kg de progesterona (s.c.; y d el último grupo recibió semilla de cícada y progesterona. Los tratamientos fueron administrados diariamentedurante 40 días y el efecto fue evaluado en las pruebas de actividad locomotora y nado forzado a los 20, 30 y 40 días de tratamiento. El grupo cícada redujo el número de cuadros cruzados en la prueba de actividad locomotora. En la prueba de nado forzado, los animales tratados con la semilla de cícada fueron los únicos que presentaron la conducta de giro, un efecto que fue prevenido por el tratamientoprevio con progesterona. La administración de vehículo y progesterona no produjo per se la conducta de giro. En conclusión, la progesterona previene las alteraciones motoras inducidas por el consumo crónico de semillas de cícada en ratas forzadas a nadar.

  13. Contrast-induced nephropathy Nefropatía inducida por medios de contraste radiológico yodados

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    María Elizabeth Gaviria Barrera

    2008-06-01

    -fareast-language:#0400; mso-bidi-language:#0400;}

    La nefropatía inducida por medios de contraste radiológico yodados (NIACR es una causa relativamente común de insuficiencia renal aguda en el medio hospitalario, asociada a un aumento considerable en la morbilidad y la mortalidad secundarias. La comprensión de su fisiopatología multifactorial, es aún incipiente, por lo que se carece de agentes profilácticos específicos y efectivos. La única medida preventiva aceptada mundialmente es la hidratación con solución salina pero se están estudiando para ese propósito otros compuestos. En este artículo se revisan la epidemiología y patogénesis de la NIACR, así como los factores de riesgo y las estrategias de prevención.

  14. Cardiopatía inducida por estrés (Tako-Tsubo. Nueva hipótesis fisiopatológica

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    Carlos E. Gadda

    2010-01-01

    Full Text Available RESUMENLa miocardiopatía inducida por estrés tiene como factor común su casi exclusiva apariciónen mujeres posmenopáusicas que acaban de sufrir una situación de estrés de gran envergaduray que clínicamente presentan un evento coronario agudo muy similar a un infartoagudo de miocardio. Al ser estudiadas de urgencia por cateterismo o ecocardiografía, en elventrículo izquierdo se observa un área de acinesia o discinesia focalizada habitualmente enla “punta”, pero con coronarias angiográficamente normales o, a lo sumo, mínimamentecomprometidas.Las coronarias pronunciadamente flexuosas también son habituales en mujeresposmenopáusicas y las arterias con estas características, al acodarse en forma extrema,pueden generar kinkings. Durante una crisis adrenérgica, estos kinkings llegan a estrangularla arteria y comprometer el flujo más allá de la sístole, lo cual, sumado a los efectos de lascatecolaminas, generaría la alteración focal y transitoria de la contractilidad que caracterizaal Tako-Tsubo.Queda claro que para afirmar esta hipótesis deben explorarse futuros pacientes en búsquedade este patrón anatómico.REV ARGENT CARDIOL 2010;78:43-45.

  15. Papel de los grupos sulfhidrilos, las prostaglandinas y el óxido nítrico endógeno, en la gastroprotección del lanosterol sobre las lesiones gástricas inducidas por etanol en rata

    OpenAIRE

    Jesús Arrieta; Benito Reyes-Trejo; Adelfo Reyes-Ramírez; María Elena Sánchez-Mendoza

    2009-01-01

    En el presente trabajo se evaluó la actividad gastroprotectora del lanosterol sobre las lesiones gástricas inducidas por etanol en ratas. El lanosterol a las dosis de 3, 10, 30 y 100 mg/kg presentó un 26, 33, 51 y 59 % de gastroprotección, respectivamente. La gastroprotección fue atenuada por N-etilmaleimida (10 mg/kg, s.c.) lo que sugiere una participación de los grupos sulfhidrilos. Sin embargo, el efecto gastroprotector no fue afectado por el éster metílico de la NG-nitro L-arginina (70 mg...

  16. Los niveles de anticuerpos anti factor plaquetario 4-heparina y el índice 4T para trombocitopenia inducida por heparina

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    Marta E. Martinuzzo

    2012-02-01

    Full Text Available La trombocitopenia inducida por heparina (HIT es un efecto adverso del tratamiento con heparina, mediada por anticuerpos anti complejo factor plaquetario 4 (PF4-heparina (HPIA. La HIT es frecuentemente moderada pero pueden desarrollarse complicaciones trombóticas. El diagnóstico precoz es importante. La detección de HPIA por ELISA tiene alta sensibilidad pero baja especificidad (títulos bajos sin significación clínica. El índice de las 4T (índice 4T puede detectar pacientes con alto riesgo de HIT. El propósito del estudio fue correlacionar los niveles de HPIA y el índice 4T de un grupo de pacientes derivados a nuestro centro. Evaluamos 84 pacientes, 34 de ellos desarrollaron trombosis. Cada médico completó un cuestionario clínico que fue remitido con la muestra a nuestro centro. Los cuestionarios fueron analizados por un investigador externo y el índice 4T se calculó previamente al ensayo. Los HPIA se determinaron por un ELISA (Asserachrom HPIA que detecta los 3 isotipos, IgG, IgM e IgA, único reactivo disponible en Argentina. Los resultados se expresaron como porcentaje de absorbancia (%ABS. La correlación del índice 4T con los HPIA fue 0.472 (rho spearman, p < 0.001. Los pacientes con índice 4T ≥ 6 presentaban %ABS mayores que los ≤ 5 (67 vs. 39, p < 0.001. Aquéllos con trombosis presentaron títulos mayores que los que no la desarrollaron (%ABS 59 vs. 39, p = 0.017. En conclusión: Los títulos altos de HPIA medidos por ELISA, que detecta los 3 isotipos, correlacionaron claramente con el índice 4T ≥ 6 y fueron más frecuentes en los pacientes con trombosis, coincidiendo con lo ya descripto para ensayos de ELISA específicos para isotipo IgG.

  17. Drug-induced acute esophageal lesions and use of ciprofloxacin Lesiones esofágicas agudas inducidas por drogas y uso de ciprofloxacino

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    V.M. Santos

    2012-04-01

    Full Text Available We report the case of a 95-year-old woman who had acute esophageal lesions while being treated with oral ciprofloxacin for an acute cystitis. On day 2 of treatment, she reported retroesternal pain with a globus sensation, and presented hematemesis and melena. There was no history of gastric or esophageal disturbances. An upper digestive endoscopy showed bleeding lesions on the middle third of the esophagus. Ciprofloxacin was discontinued and a proton pump inhibitor was administered. One week later, the endoscopic aspect of the esophagus was normal. Only two cases of ciprofloxacin-induced esophageal lesions have been reported previously. A short review of this kind of esophageal injuries is presented, focusing on the main risk factors and preventive measures.Presentamos el caso de una mujer de 95 años con lesiones agudas del esófago que tomaba ciprofloxacino por cistitis aguda. La paciente refería dolor y sensación de cuerpo estraño retroesternal asociados con hematemesis y melena, después del segundo día de tratamiento. No había antecedentes personales de trastornos gástricos o esofágicos. La endoscopia digestiva objetivó lesiones sangrantes en el tercio medio del esófago. El uso de ciprofloxacino fue suspendido y se utilizó un inhibidor de la bomba de protones. Una semana más tarde, el aspecto endoscópico del esófago fue considerado normal. Dos únicos casos de lesiones esofágicas inducidas por ciprofloxacino han sido previamente publicados. Se presenta una revisión breve acerca de este tipo de lesiones del esófago, con énfasis a los principales factores de riesgo y medidas de prevención.

  18. “Corrosión Inducida por Bacterias Sulfato Reductoras Termófilas de 60°C en la Unión Soldada del Acero API 5L- X60.”

    OpenAIRE

    Romero Romero, Justo Román

    2012-01-01

    En esta investigación se estudio el efecto de la corrosión inducida por Bacterias Sulfato Reductoras (BSR) termófilas a 60oC en el metal base (MB) y la unión soldada (US) del acero API X-60. Las bacterias sulfato reductoras fueron aisladas en el medio sólido postgate con la técnica de estriado, y fueron resembradas hasta obtener la misma morfología. El medio postgate fue seleccionado entre otros medios de cultivo, por el óptimo crecimiento que presento la BSR. Se preparar...

  19. Funciones inducidas conexas

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    Sergio A. Pérez

    2013-01-01

    Full Text Available Se dice que una función f : X → Y definida entre espacios topológi- cos es conexa si la gráfica Γ(f = {(x, f (x : x ∈ X} es conexa. Dado un continuo X, se consideran los hiperespacios: 2X , la colección de todos los subconjuntos cerrados no vacíos de X; C(X, el conjunto de todos los sub- continuos de X; y Fn (X, los subconjuntos no vacíos de a lo más n puntos de X. Además, dada una función f : X → Y entre continuos, consideramos las funciones inducidas 2f : 2X → 2Y definidas por 2f (A = f (A para cada A ∈ 2X ; Fn (f : Fn (X → Fn (Y , la función restricción Fn (f = 2f |Fn (X ; y si f es una función de Darboux débil, definimos C(f : C(X → C(Y por C(f = 2f |C(X . En este artículo estudiamos las relaciones entre las siguientes cinco afirmaciones: 1 f es conexa; 2 C(f es conexa; 3 Fn (f es conexa, para algún n ≥ 2; 4 Fn (f es conexa, para todo n ≥ 2; 5 2f es conexa.

  20. El pretratamiento agudo y subcrónico con fármacos anticonvulsivantes modifica las crisis generalizadas inducidas por el pentilenetetrazol en el ratón

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    Luisa L. Rocha

    2008-09-01

    Full Text Available Objetivo: El incremento en el contenido de GABA cerebral o la administración de un agente GABA-mimético se emplea como un tratamiento antiepiléptico eficaz. Sin embargo, se sugiere que el empleo de fármacos que alteran continuamente la transmisión sináptica puede afectar al sistema nervioso. En el presente estudio se evaluaron los efectos del pretratamiento agudo (una administración y subcrónico (administraciones diarias por 7 días de diazepam (DZP; 10 mg/kg, ip, gabapentina (GBP, 100 mg/kg, vo y vigabatrina (VGB, 500 mg/kg, vo en las crisis generalizadas inducidas por pentilenetetrazol (PTZ, 80 mg/kg ip.Materiales y métodos: Ratones macho de la cepa taconic (20-25 g recibieron tratamiento agudo y subcrónico de DZP, GBP o VGB y 24 h después de la última administración se aplicó PTZ. Se evaluaron las latencias a la primera crisis clónica, a la fase tónica así como la incidencia de muerte.Resultados: El pretratamiento agudo con DZP protegió 100% a los animales de los efectos del PTZ, mientras que su administración subcrónica redujo la latencia a la crisis clónica (21%; p<0.05, la fase tónica (27%, p<0.05 y muerte (37%, p<0.05. La aplicación aguda de VGB protegió 100% a los animales de los efectos del PTZ, mientras que su aplicación subcrónica aumentó la latencia a las crisis clónicas (32%, p<0.05, aunque facilitó la aparición de la crisis tónica (55%, p<0.05 y la muerte (58%, p<0.05. La administración aguda de GBP elevó la latencia a la crisis clónica (52%, p<0.05, mientras que su administración subcrónica no modificó el efecto producido por PTZ.Conclusiones: Estos resultados sugieren que el pretratamiento agudo y subcrónico de fármacos que incrementan la transmisión GABAérgica modifican diferencialmente la susceptibilidad a las crisis por PTZ y que su administración repetida puede facilitar la producción de crisis convulsivas.

  1. Síntesis de xerogeles de carbono inducida por microondas para su uso como electrodos en supercondensadores

    OpenAIRE

    Gómez Calvo, Esther

    2013-01-01

    Los supercondensadores son sistemas de almacenamiento de energía muy prometedores debido a la elevada capacidad de almacenamiento de energía que ofrecen y a su excelente ciclabilidad. No obstante, hoy en día los valores de densidad de energía suministrada aún distan de los ofrecidos por las baterías y/o pilas de combustible, motivo por el cuál es necesario avanzar en esta temática. Las investigaciones sobre los supercondensadores se centran, fundamentalmente, en la búsqueda de nuevos material...

  2. Arteriopatía periférica crónica inducida por cocaína Chronic peripheral arterial disease induced by cocaine

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    Sonia Pankl

    2012-02-01

    Full Text Available La trombosis periférica aguda inducida por cocaína ha sido descripta en la literatura, siendo una complicación poco común. Si bien existen comunicaciones que reflejan los efectos crónicos de la cocaína sobre el sistema arterial periférico, no hay casos publicados de tal complicación en ausencia de otros factores de riesgo. Se presenta el caso de una mujer de 22 años de edad con antecedentes de consumo de cocaína intranasal de 3 gramos por semana durante un año, que consultó por claudicación intermitente a los 200 metros asociada a dolor y parestesias en miembro inferior izquierdo de 2 meses de evolución. El ecodoppler arterial evidenció una estenosis mayor del 70% en la arteria femoral superficial izquierda. Se realizaron estudios complementarios descartando otras etiologías probables. Se inició tratamiento con ácido acetilsalicílico, cilostazol y ejercicio reglado, asociado a terapia de apoyo para mantenimiento del cese del consumo de cocaína, con buena respuesta. Se destaca la importancia de la difusión de información a los pacientes, dado que la mayoría de la población desconoce las complicaciones cardiovasculares de dicha adicción. Es indispensable indagar sobre el consumo de cocaína en pacientes jóvenes con arteriopatía sin factores de riesgo aparentes.Cocaine induced acute peripheral thrombosis, though a rare complication, has been described in the literature. Although there are reports describing the chronic effects of cocaine on the peripheral arterial system, there are no published cases of this complication when other risk factors are lacking. We report on a 22 year old female patient, with intranasal consumption of 3 grams of cocaine per week for a year, who consulted for intermittent claudication at 200 meters, associated to left lower limb pain and paresthesiae for the last two months. Arterial Doppler ultrasonography showed a stenosis greater than 70% in the superficial left femoral artery. Other

  3. Efectos de la alcalosis metabólica inducida por la dieta en el rendimiento anaeróbico de alta intensidad Effects of the metabolic alkalosis induced by the diet in the high intensity anaerobic performance

    OpenAIRE

    O. Ríos Enríquez; Guerra-Hernández, E.; B. Feriche Fernández-Castanys

    2010-01-01

    Objetivos: El propósito principal de este estudio es comparar el efecto de una alcalosis y acidosis inducidas por la dieta sobre el rendimiento en un esfuerzo anaeróbico láctico mantenido. Métodos: Para ello, trece sujetos activos se sometieron de forma cruzada a sendas dietas durante dos días y medio. Inmediatamente después realizaron una prueba de esfuerzo anaeróbica láctica máxima de estado estable hasta el agotamiento sobre cicloergómetro a 250 W. Resultados: La valoración de las dietas m...

  4. Determinación de la profundidad y duración de la neutropenia inducida por ciclofosfamida en ratones hembras MPF de la cepa Udea: ICR(cd-1

    Directory of Open Access Journals (Sweden)

    Omar Vesga

    2004-02-01

    Full Text Available

    El modelo murino de infección del muslo emplea animales neutropénicos para poder determinar la eficacia intrínseca de los antibióticos in vivo. Sin embargo, no se ha definido el número de neutrófilos y la duración de la neutropenia inducida por ciclofosfamida (CFM intraperitoneal (IP, información fundamental
    para valorar la reproducibilidad y confiabilidad del modelo.

     

     

  5. Valor de la troponina T como marcador de daño miocárdico en recién nacidos de madres con hipertensión inducida por la gestación

    OpenAIRE

    Bas, José Ignacio

    2009-01-01

    Tesis (Doctor)--Universidad Nacional de Córdoba. Facultad de Ciencias Médicas, 2009 La hipertensión inducida por la gestación (HIG) puede reducir el flujo sanguíneo útero-placentario, provocar hipoxia, desnutrición fetal y restricción del crecimiento intrauterino (RCIU).La HIG puede generar un medio intrauterino adverso en su función de proveer oxígeno y nutrientes al feto, el cual inicia respuestas de adaptación para sobrevivir. Estos mecanismos de defensa privilegian el aporte de oxígeno...

  6. Alteraciones cromosómicas estructurales inducidas por bioflavonoides de la dieta en linfocitos de anemia de Fanconi

    OpenAIRE

    Galeano, Liliana; Guevara, Gonzalo

    2010-01-01

    Introducción La anemia de Fanconi es una enfermedad genética con herencia autosómica recesiva caracterizada por aplasia medular, predisposición a leucemia mieloide aguda, tumores sólidos y aumento en la inestabilidad cromosómica. Este síndrome puede considerarse como modelo biológico para analizar sustancias naturales con posible efecto genotóxico, difíciles de evaluar en células normales. Los objetivos de este estudio son describir y cuantificar las alteraciones cromosómicas estructurales in...

  7. Mecanismos implicados en las conductas inducidas por el alcohol: el papel de los enzimas cerebrales responsables de metabolismo del acetaldehido

    OpenAIRE

    Escarabajal-Arrieta, María-Dolores

    2013-01-01

    [ES] Existe un constante aumento del consumo de bebidas alcohólicas unido a un porcentaje de personas alcohólicas cada vez mayor lo que demanda nuevos estudios que puedan aportar algo de claridad a la pregunta de por qué la gente bebe. En este sentido se presenta el estudio realizado sobre los sistemas enzimáticos implicados en el metabolismo del etanol tras las manipulaciones farmacológicas de la actividad de la catalasa y de la aldehído deshidrogenasa (ALDH) cerebrales, manipulaciones q...

  8. Estudio de las respuestas de defensa inducidas por elicitores en cultivos de células vegetales.

    OpenAIRE

    2013-01-01

    En esta memoria, los cultivos celulares de Capsicum, Daucus carota y Taxus x media sometidos a elicitación con ciclodextrinas y jasmonato de metilo, se han empleado como sistemas de producción de metabolitos secundarios de naturaleza terpenoide, que además de ser importantes en la defensa vegetal, suponen un importante recurso natural para la obtención de fármacos, aditivos alimentarios, nutracéuticos y cosméticos. Por otro lado, la elicitación también se ha utilizado como herramienta par...

  9. CONTRIBUCION DEL CANAL TIPO TASK A LA HIPERREACTIVIDAD DEL CUERPO CAROTÍDEO INDUCIDA POR HIPOXIA INTERMITENTE CRONICA

    OpenAIRE

    ORTIZ CISTERNAS, FERNANDO ANDRES

    2011-01-01

    El cuerpo carotídeo (CC) es el principal órgano quimiosensorial periférico que detecta los cambios en los niveles arteriales de P02, PC02 y pH. En respuesta a la hipoxia aguda las células quimiorreceptoras (tipo 1) del ce se despolarizan gatillando un aumento del ci+ intracelular y la concomitante liberación de uno o más neurotransmisores. Se ha propuesto que -al menos en ratas neonatas- esta despolarización se inicia con la inhibición por hipoxia de una corriente de K+ de fuga tipo TASK, ...

  10. Evaluación de la reacción acrosomal en espermatozoides humanos inducida por oligosacáridos

    Directory of Open Access Journals (Sweden)

    Angela Cadavid

    2004-02-01

    Full Text Available

    La capacitación es un proceso necesario que debe sufrir el espermatozoide para poder llevar a cabo la fertilización del ocito. Este evento se da durante su paso a través del tracto reproductor femenino, donde ocurre la interacción entre los espermatozoides y las células del epitelio oviductal, la cual es dependiente de carbohidratos. Adicionalmente, el espermatozoide necesita interactuar con una serie de moléculas presentes en la zona pelúcida, que permiten un reconocimiento específico entre el espermatozoide y el oocito. La interacción entre gametos es específica de especie; ésto indica que la zona pelúcida posee ligandos que son reconocidos por los espermatozoides y que éstos poseen receptores que le permiten la unión al oocito (1.

     

     

  11. ALTERACIONES CELULARES INDUCIDAS POR EL IÓN AL 3+ EN DOS VARIEDADES CUBANAS DE ARROZ (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Idioleidys Alvarez

    2005-01-01

    Full Text Available Con el propósito de estudiar las modificaciones, que a nivel celular provoca el aluminio en el sistema radicular del arroz, se desarrolló un experimento, en el cual se emplearon diferentes dosis de AlCl3 para imponer la condición de estrés. Para el estudio los ápices radicales de las plántulas se procesaron por un método de disminución progresiva de la temperatura (PLT y se incluyeron en resina Lowicryl para su posterior seccionamiento y observación al microscopio de Contraste de Fase. Se apreciaron cambios en la orientación del crecimiento de células epidérmicas y corticales, lo cual contribuyó a la inhibición del alargamiento celular. Las paredes de algunas células se observaron engrosadas e irregulares y se evidenció un incremento en el tamaño de las vacuolas, fenómeno observado también en otras plantas ante la exposición con aluminio. Los resultados obtenidos demuestran que el aluminio provoca alteraciones en las células radicales del arroz, algunas de las cuales son responsables estructuralmente de cambios morfológicos como el engrosamiento y acortamiento de las raíces, hallados con anterioridad en nuestro laboratorio para el cultivo del arroz ante este estrés.

  12. Lesiones inducidas por contacto directo con antenas de radio en vehículos de Caballería

    Directory of Open Access Journals (Sweden)

    I. Díaz de Tuesta Revilla

    2014-09-01

    Full Text Available La exposición sostenida a emisiones de radio podría estar relacionada con lesiones en el tejido subcutáneo. Presentamos dos casos sucedidos en tiradores de vehículo explorador de Caballería (VEC tras unas maniobras en zona de operaciones Líbano, consistentes en una inusual tumefacción del tejido adiposo en antebrazo derecho sin antecedente de contusiones, ni contactos químicos o irradiación conocida, y con piel íntegra, que coincide con zonas de posible contacto mantenido con la antena del vehículo. La causalidad no es determinante por tratarse de una relación observacional, pero los hallazgos sugieren que deberían tomarse medidas en relación con la reducción del riesgo de exposición a radiaciones electromagnéticas en operarios de carros con antenas plegables.

  13. Programación temprana de alteraciones en el sistema del óxido nítrico renal y vascular inducidas por la deficiencia de cinc

    Directory of Open Access Journals (Sweden)

    María A. Costa

    2008-01-01

    Full Text Available Resumen:IntroducciónNumerosos estudios mostraron que la deficiencia nutricional durante la vida fetal y posnatal predisponen al desarrollo de patologías en la vida adulta, como la hipertensión arterial y las enfermedades renales. La distribución ubicua del cinc y sus propiedades químicas determinan su esencialidad en los sistemas biológicos.ObjetivosEvaluar si las alteraciones renales y cardiovasculares en la vida adulta inducidas por la restricción moderada de cinc durante la vida fetal, la lactancia y/o el crecimiento se asocian con cambios en el sistema del óxido nítrico.Material y métodosRatas Wistar hembra recibieron durante la preñez hasta el destete de las crías una dieta control o una baja en cinc. Luego del destete, las crías macho se asignaron al azar a dos grupos que recibieron una dieta control o una baja en cinc durante 60 días.ResultadosLos resultados mostraron que el aporte insuficiente de cinc durante el crecimiento previo y/o posterior al destete indujo un aumento de la presión arterial y una disminución del volumen de filtrado glomerular en la vida adulta, asociados con una disminución del sistema del óxido nítrico renal y vascular. Además, el bajo aporte de este mineral durante la vida fetal indujo un peso menor al nacer, que se correlacionó en forma negativa con la presión arterial en la vida adulta.ConclusionesEste trabajo brinda evidencias importantes que sugieren que el aporte inadecuado de cinc durante el crecimiento prenatal y posnatal constituye un factor de riesgo cardiovascular y renal, dado que induce alteraciones en la regulación de la presión arterial y en la función renal en el individuo adulto.REV ARGENT CARDIOL 2008;76:459-464.

  14. Modificaciones hematológicas inducidas por eritropoyetina frente a hipoxia normobárica intermitente Hematologic changes induced by erythropoietin versus intermittent normobaric hypoxia

    Directory of Open Access Journals (Sweden)

    F. Sanchis-Gomar

    2010-12-01

    Full Text Available

    Publicaciones recientes reflejan la preocupación de las autoridades antidopaje por el uso de sistemas simuladores de altitud y la posibilidad de considerarlos métodos dopantes. El objetivo de nuestro estudio fue el de comparar las modificaciones hematológicas inducidas por dos tratamientos con eritropoyetina recombinante humana (rHuEpo a diferentes dosis, frente a un protocolo de hipoxia normobárica intermitente (HNI en un modelo animal.
    Veinticuatro ratas Wistar macho jóvenes fueron divididas en 3 grupos experimentales: grupo sometido a HNI (12h pO2 12% /12h pO2 21% (n=8; grupo tratado con una dosis de 300 UI de rHuEpo (n=8 y grupo tratado con 500 UI de rHuEpo (n=8. Se extrajeron dos muestras de sangre a cada uno de los grupos experimentales (antes y después de los tratamientos. Nuestros resultados muestran incrementos muy similares, y estadísticamente significativos, en los valores de hemoglobina, de hematocrito y de reticulocitos, tanto en el grupo HNI como en el grupo tratado con 300 UI de rHuEpo tras los 15 días de tratamiento. El tratamiento con 500 UI de rHuEpo produjo un incremento significativamente mayor.
    La principal conclusión de nuestro estudio es que las modificaciones de los parámetros hematológicos obtenidas mediante un protocolo de HNI son similares a las obtenidas con un tratamiento con 300 UI de rHuEpo.
    Palabras clave: Hemoglobina, hematocrito, reticulocitos, dopaje

    Recent publications reflect the anti-doping authorities’ concern about the use of altitude simulator systems, since these technologies could be considered as doping methods. The major aim of our study was to compare the effect of two different rHuEpo treatments with a normobaric intermittent hypoxic (NIH protocol regarding the modifications of hemoglobin, hematocrit and reticulocytes values in an animal model. Although these hematological parameters are of secondary nature, some international sport federations

  15. Análisis proteómico de la resistencia inducida por micorrización al patógeno foliar Sclerotinia sclerotiorum en frijol (Phaseolus vulgaris l.)

    OpenAIRE

    2014-01-01

    En los últimos años se han reportado diversos estudios sobre la resistencia inducida por micorrización al ataque de patógenos, en éstos se han determinado los cambios de expresión de genes y proteínas que ocurren en las raíces de plantas colonizadas por hongos micorrízicos arbusculares. Recientemente, se han iniciado estudios para entender cómo afecta esta interacción a la parte aérea de la planta. En nuestro grupo de investigación se llevó a cabo el estudio del efecto de la micorrizaci...

  16. Hemólisis inducida por el ejercicio: relación entre el nivel de actividad de la glucosa-6-fosfato deshidrogenasa y el grado de hemólisis

    Directory of Open Access Journals (Sweden)

    Javier F. Bonilla

    2008-06-01

    Full Text Available Introducción: La oxidación, al igual que la hemólisis asociadas con el ejercicio tanto moderado como extenuante han sido condiciones objeto de múltiples estudios, pero sólo en algunos recientes se evaluó cómo las variaciones en la capacidad de los mecanismos antioxidantes enzimáticos eritrocitarios específicos y genéticamente determinados, condicionan distintos grados de susceptibilidad a la hemólisis inducida por el ejercicio, pero esos trabajos se han hecho sobre todo en individuos no sedentarios y con deficiencia franca de la enzima G6PD.Objetivo: El propósito de este trabajo fue determinar si existe o no relación entre el nivel de actividad de la enzima eritrocitaria G6PD y el grado de hemólisis inducida por el ejercicio en hombres adultos sedentarios en apariencia sanos, luego de un tiempo experimental de ejercicio moderado pre-extenuante y equivalente en modalidad y magnitud. Metodología: Se evaluaron 25 voluntarios hombres, sedentarios, en apariencia sanos; se les aplicó una sesión de ejercicio, sobre un cicloergómetro, de una hora de duración, a 70% del VO2pico previamente hallado. Sobre la base de la concentración de hemoglobina plasmática se calculó el porcentaje de hemólisis y la haptoglobina consumida, tomando en cuenta la variación en el plasma de la haptoglobina y la hemólisis intravascular inmediatamente después y hasta tres horas luego del ejercicio. Resultados: Se pudo determinar que los individuos presentaron, con base en la determinación de Hb plasmática libre, % de hemólisis y consumo de haptoglobina, hemólisis intravascular durante y hasta por lo menos tres horas post-ejercicio. Conclusiones: La magnitud de la hemólisis presentada, por un lado, tuvo una relación inversa significativa con la actividad de la G6PD, y por otro, que tal magnitud tuvo un comportamiento significativamente distinto por debajo del percentil 40 de la actividad hallada para G6PD y por encima de la misma, o sea, la

  17. Efecto neuroprotector de los cannabinoides sobre la muerte neuronal inducida por Ampa en la médula espinal: Activación conjunta de los receptores CB1 y CB2

    Directory of Open Access Journals (Sweden)

    Carmen Guaza

    2005-03-01

    Full Text Available La sobreactivación de receptores de glutamato, como el receptor AMPA, induce la muerte neural por un proceso denominado excitotoxicidad, el cual ha sido claramente implicado en enfermedades agudas del sistema nerviso central (SNC, particularmente con daño axonal.

  18. Funciones inducidas conexas

    Directory of Open Access Journals (Sweden)

    Sergio A. Pérez

    2013-12-01

    Full Text Available Se dice que una función f : X → Y definida entre espacios topológicos es conexa si la gráfica Γ(f = {(x, f(x : x ∈ X} es conexa. Dado un continuo X, se consideran los hiperespacios: 2 X, la colección de todos los subconjuntos cerrados no vacíos de X; C(X, el conjunto de todos los subcontinuos de X; y Fn(X, los subconjuntos no vacíos de a lo más n puntos de X. Además, dada una función f : X → Y entre continuos, consideramos las funciones inducidas 2 f : 2X → 2 Y definidas por 2 f (A = f(A para cada A ∈ 2 X; Fn(f: Fn(X → Fn(Y , la función restricción Fn(f = 2f |Fn(X ; y si f es una función de Darboux débil, definimos C(f: C(X → C(Y por C(f = 2f |C(X . En este artículo estudiamos las relaciones entre las siguientes cinco afirmaciones: 1 f es conexa; 2 C(f es conexa; 3 Fn(f es conexa, para algún n ≥ 2; 4 Fn(f es conexa, para todo n ≥ 2; 5 2 f es conexa. Abstract. A function between topological spaces f : X → Y is said to be connected provided that the graph Γ(f = {(x, f(x : x ∈ X} is connected. Given a continuum X, some hyperspaces are considered: 2 X, the collection of all non-empty closed subsets of X; C(X, the set of all subcontinua of X, and Fn(X the set of nonempty subsets of at most n points of X. Moreover, given f : X → Y a function between continua, consider the induced functions: 2 f : 2X → 2 Y , defined by 2 f (A = f(A for each A ∈ 2 X; Fn(f: Fn(X → Fn(Y , the restriction function Fn(f = 2f |Fn(X ; and, if f is a weak Darboux function, we define C(f: C(X → C(Y by C(f = 2f |C(X . In this paper we study the relationships between the following five statements: 1 f is connected; 2 C(f is connected; 3 Fn(f is connected, for some n ≥ 2; 4 Fn(f is connected, for all n ≥ 2; 5 2 f is connected.

  19. Estudio de la influencia del Cu y Ni en la cinética de transformación martensítica inducida por deformación en fundiciones nodulares austemperadas

    Directory of Open Access Journals (Sweden)

    Guzmán, D.

    2013-06-01

    Full Text Available The objective of this work was to study the influence of copper and nickel on the kinetics of strain-induced martensite in austempered ductile cast iron. The austempered ductile cast irons were obtained from two ductile cast irons with different copper and nickel contents by means of austempering treatment. The deformation was carried out using a rolling mill. The quantification of the phases was obtained by means of X ray diffraction, while the microstructural characterization was carried out using optical and scanning electron microscopy. It was proved that the kinetics of strain-induced martensite in austempered ductile cast iron can be modeled using the equations proposed by Olson- Cohen and Chang et al. Based on the results obtained from these analyses, it is possible to conclude that the nickel and copper complicate the martensite transformation because these elements increase the staking fault energy of the austenite and its thermodynamic stability.El objetivo de este trabajo fue estudiar el efecto del cobre y níquel en la cinética de la transformación martensítica inducida por deformación en fundiciones nodulares austemperadas. Las fundiciones utilizadas se fabricaron mediante austemperado, a partir de dos fundiciones nodulares, con diferentes contenidos de cobre y níquel. La deformación se realizó en un laminador de rodillo. La cuantificación de las fases se realizó mediante difracción de rayos X, mientras que la caracterización microestructural se efectuó utilizando microscopía óptica y electrónica de barrido. Se comprobó que la cinética de transformación martensítica inducida por deformación en fundiciones nodulares austemperadas puede ser modelada mediante los modelos de Olson-Cohen y Chang et al. Basándose en los resultados obtenidos de estos ajustes, se concluye que tanto el níquel como el cobre dificultan la transformación martensítica debido a que estos elementos aumentan la energía de falla de

  20. El coactivador de receptores nucleares RAC3 tiene un rol protector de la Apoptosis inducida por distintos estímulos RAC3 nuclear receptor co-activator has a protective role in the apoptosis induced by different stimuli

    Directory of Open Access Journals (Sweden)

    Georgina P. Coló

    2007-10-01

    Full Text Available RAC3 pertenece a la familia de coactivadores de receptores nucleares p160, y se encuentra sobreexpresado en varios tumores. Demostramos previamente que RAC3 es coactivador del factor de transcripción anti-apoptótico NF-kapa;B. En este trabajo investigamos su rol en la apoptosis inducida por H2O2 en una línea celular no tumoral derivada de riñón embrionario humano (HEK293, y por el ligando inductor de apoptosis relacionado a TNF (TRAIL en una línea de leucemia mieloide crónica humana (K562, naturalmente resistente a la muerte por este estímulo. Observamos que las células tumorales K562 poseen niveles altos de RAC3 comparados con las células no tumorales HEK293. La sobreexpresión normal de coactivador o por transfección, inhibe la apoptosis mediante una disminución de la activación de caspasas, translocación del factor inductor de apoptosis (AIF al núcleo, aumento de la actividad de NF-kapa;B y las quinasas AKT y p38 y disminución de la quinasa ERK. Lo opuesto fue observado por disminución de RAC3 mediante la técnica de ARN interferente (RNAi en K562, aumentando así la apoptosis inducida por TRAIL. Estas evidencias sugieren que una sobreexpresión de RAC3 contribuye al desarrollo de tumores, participando en las cascadas que controlan la muerte celular por mecanismos no estrictamente dependientes de hormonas esteroideas y/o de acetilación, constituyendo esto un posible blanco de ataque para el tratamiento de tumores.RAC3 belongs to the family of p160 nuclear receptors coactivators and it is over-expressed in several tumors. We have previously shown that RAC3 is a NF-kappa;B coactivator. In this paper, we investigated the role of RAC3 in cell-sensitivity to apoptosis, using H2O2 in the human embryonic kidney cell line (HEK293, and tumor necrosis factor-related apoptosis inducing ligand (TRAIL in a human chronic myeloid leukemia cell line (K562 naturally resistant to TRAIL. We observed that the tumoral K562 cells have high levels

  1. Disquinesia tardía inducida por neurolépticos y discapacidad en usuarios de larga estancia del Hospital Psiquiátrico Dr. Roberto Chacón Paut

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    José Rodolfo Gutiérrez -Villalobos

    2003-09-01

    Full Text Available Justificación y objetivo: Los usuarios de larga estancia del Hospital Dr. Roberto Chacón Paut reciben tratamientos prolongados con neurolépticos, lo cual los expone a sufrir disquinesia tardía (DT. Este estudio tiene como objetivo determinar la prevalencia de DT inducida por neurolépticos, la discapacidad que genera, los factores de riesgo de sufrir disquinesia y sus efectos discapacitantes en esta población. Métodos: A 173 usuarios, se les administraron los instrumentos: Criterios de investigación DSM-IV para DT inducida por neurolépticos, Escala de movimientos involuntarios anormales e Indice de Barthel, con el fin de determinar la prevalencia de DT y la discapacidad por movimientos anormales y para ABVD. Se utilizó un análisis de regresión logística para establecer los factores de riesgo de sufrir DT y sus efectos discapacitantes. Resultados: La prevalencia general de DT fue del 54%. Este porcentaje fue superior en mujeres y aumentó en los grupos de mayor edad y con tratamientos prolongados. Las mujeres presentaron discapacidad más severa que los varones. La edad avanzada y años de tratamiento con neurolépticos, se asociaron con una discapacidad menos severa. Se encontró un riesgo significativo de sufrir DT y discapacidad moderada por movimientos anormales, 1,06 veces más frecuente por cada año de tratamiento, y de total dependencia para ABVD, 10,07 veces más frecuente en mujeres que en varones. Conclusiones:\tLos años de tratamiento con neurolépticos fue el único factor de riesgo identificado en la ocurrencia de DT y discapacidad moderada por movimientos anormales. El sexo femenino se asoció con total dependencia para ABVD.Background and aim: To establish the prevalence of tardive dyskinesia (TD induced by neuroleptics. The risk factors involved and the disability effects in chronic users at the Chacón Paut Psychiatric Hospital. Method: 173 patients were studied. The DSM-IV Investigation Criteria for Tardive

  2. Funciones inducidas conexas

    OpenAIRE

    2013-01-01

    Se dice que una función f : X → Y definida entre espacios topológicos es conexa si la gráfica Γ(f) = {(x, f(x)) : x ∈ X} es conexa. Dado un continuo X, se consideran los hiperespacios: 2 X, la colección de todos los subconjuntos cerrados no vacíos de X; C(X), el conjunto de todos los subcontinuos de X; y Fn(X), los subconjuntos no vacíos de a lo más n puntos de X. Además, dada una función f : X → Y entre continuos, consideramos las funciones inducidas 2 f : 2X → 2 ...

  3. Mitogen activated protein kinases blockade improves lipopolysaccharide-induced ileal motor disturbances El bloqueo de las proteínas cinasas activadas por mitógenos mejora las alteraciones motoras inducidas por el lipopolisacárido en íleon

    Directory of Open Access Journals (Sweden)

    Sergio Gonzalo

    2012-06-01

    Full Text Available Background: several diseases such as sepsis can affect the ileum. Lipopolysaccharide (LPS, an endotoxin present in the cell wall of gram negative bacteria, is a causative agent of sepsis. Objectives: the aims of this study were: a to investigate the role of mitogen activated protein kinases (MAPKs in the effect of LPS on the acetylcholine-induced contractions of rabbit ileum; and b to study the localization of MAPKs in the ileum. Material and methods: ileal contractility was studied in an organ bath and MAPKs were localized by immunohistochemistry. Results: acetylcholine-induced contractions decreased with LPS. SB203580, SP600125 and U0126 blocked the effect of LPS on the acetylcholine-induced contractions. Phosphorylated p38 and ERK were detected in neurons of myenteric plexus and phosphorylated p38 and JNK in smooth muscle cells of ileum. Conclusion: we can suggest that p38, JNK, and ERK MAPKs are involved in the mechanism of action of LPS in the ileum.Introducción: varias enfermedades como la sepsis pueden afectar al íleon. El lipopolisacárido (LPS, una endotoxina presente en la pared celular de las bacterias gram-negativas, es un agente causal de la sepsis. Objetivos: los objetivos del presente estudio fueron: a investigar el papel de las proteína cinasas activadas por mitógenos (MAPKs en los efectos del LPS en las contracciones inducidas por acetilcolina en el íleon de conejo; y b estudiar la localización de las MAPKs en el íleon. Material y métodos: la contractilidad ileal se estudió en un baño de órganos y las MAPKs se localizaron mediante inmunohistoquímica. Resultados: el LPS disminuyó las contracciones inducidas por acetilcolina. El SB203580, el SP600125 y el U0126 bloquearon los efectos del LPS sobre las contracciones inducidas por acetilcolina. La p38 y la ERK fosforiladas se detectaron en las neuronas del plexo mientérico y la p38 y la JNK fosforiladas en las células del músculo liso del íleon. Conclusi

  4. Estudio de la enteropatía inducida por péptidos de gliadinas y ligandos de la inmunidad innata en modelos experimentales

    OpenAIRE

    2015-01-01

    La Enfermedad Celíaca (EC) es una enteropatía crónica de base inmune desencadenada por la ingestión de gluten en pacientes con predisposición genética. Se caracteriza por cambios histológicos severos en la mucosa duodenal definidos por atrofia vellositaria, infiltrado linfocitario e hiperplasia de criptas. Es una patología de alta prevalencia (estimada en un 1% de la población) con una sintomatología variada que puede estar asociada a complicaciones severas. Esta enfermedad ha sido ...

  5. Caracterización de la neoplasia intraepitelial cervical inducida por el virus del papiloma humano en pacientes seropositivas a virus de la inmunodeficiencia humana

    OpenAIRE

    Rodríguez Bravo, Tomás Carlos

    2014-01-01

    [ES] Hemos pretendido caracterizar el comportamiento y la respuesta al tratamiento antirretroviral de las lesiones cervicales producidas por el virus del papiloma humano (HPV) en las pacientes infectadas también por el virus de la inmunodeficiencia adquirida (VIH). Se trata de de un estudio observacional y prospectivo, en el que la selección de la muestra procede del Servicio de enfermedades infecciosas del Complejo Hospitalario de Salamanca. Las pacientes fueron remitidas para control gin...

  6. Mifepristone inhibits MPA-and FGF2-induced mammary tumor growth but not FGF2-induced mammary hyperplasia La mifepristona inhibe el crecimiento de carcinomas mamarios inducidos por MPA o por FGF2 pero no las hiperplasias mamarias inducidas por FGF2

    Directory of Open Access Journals (Sweden)

    Juan P. Cerliani

    2010-12-01

    tratamiento con RU486. Por otra parte, el RU486 revierte la hiperplasia paraductal inducida por MPA y sólo induce un efecto agonista parcial. Estos datos sugieren que el efecto del FGF2 en la glándula mamaria es RP independiente. Demostramos que el tumor C4-HD crece in vivo con la administración intratumoral de FGF2. En este caso, la histología revela un mayor grado de diferenciación, similar al observado en el tumor C4-HI que crece sin el aporte exógeno de hormonas. El RU-486 inhibió tanto la estimulación inducida por MPA como por FGF2. Los resultados apoyan la hipótesis de que el FGF2 estromal activa al RP induciendo el crecimiento hormono independiente de tumores mamarios.

  7. Factores inmunereactivos "digoxin-like" en la natriuresis tras expansi??n de volumen central inducida por atiortostatismo : Interrelaciones con el SRA-aldosterona ADH y prostaglandinas

    OpenAIRE

    Rodr??guez L??pez, Ju??n

    1989-01-01

    el antiortostatismo se muestra como m??todo de expansi??n de volumen con natriuresis, diuresis, (-) adh, (-) s.r.a.-aldosterona, pero no como m??todo que produzca elevaci??n de los f.digoxin-like. el tratamiento previo con captopril incrementa la diuresis y natriuresis con respecto al grupo control, tambi??n incrementa la diuresis y natriuresis con respecto al grupo control, al igual que los niveles hormonales de adh, aldosterona y digoxin-like por una flujo dependencia de orina que se ve cor...

  8. Osteonecrosis de los maxilares inducida por bifosfonatos: prevención y actitud terapéutica Bisphosphonate induced osteonecrosis of the jaws: prevention and therapeutic approach

    OpenAIRE

    F.J. Barrientos Lezcano; B. Peral Cagigal; G. de la Peña Varela; L.A. Sánchez Cuéllar; García Cantera, J. M.; A. Serrat Soto; A. Verrier Hernández

    2007-01-01

    Introducción. La osteonecrosis maxilar o mandibular por bifosfonatos puede convertirse en una epidemia debido a la amplia difusión de estos fármacos entre la población. Material y método. Se muestra un protocolo para la prevención y el tratamiento de esta enfermedad. Se presentan tres casos de osteonecrosis maxilar/mandibular. Resultados. Es difícil lograr una curación completa; sin embargo es posible detener la progresión de la enfermedad. Discusión. La cirugía y la suspensión de la terapia ...

  9. Efecto del estrés durante diferentes etapas del ciclo vital sobre el desarrollo de obesidad inducida por la dieta

    OpenAIRE

    Paternain, L. (Laura); Martinez, J A; Campión-Zabalza, J. (Javier)

    2014-01-01

    La creciente prevalencia de la obesidad no puede ser atribuible únicamente a factores genéticos o a una mala nutrición como pueden ser las dietas altas en grasa, sino también al estilo de vida y a factores ambientales adversos. Dentro del estilo de vida, la sociedad actual se caracteriza por tener un ritmo acelerado, lo que produce una elevación de la tasa de estrés en la población. Este aumento paralelo tanto de las tasas de obesidad como del estrés, hace necesario el estudio de la interacci...

  10. Hiperplasia gingival inducida por Ciclosporina A en transplantes renales : estudio clínico, morfométrico inmunohistoquímico y ultraestructural

    OpenAIRE

    Mesa Aguado, Francisco Luis

    2013-01-01

    El aumento en el tamaño de la encia es uno de los principales signos de enfermedad gingival, y la hiperplasia iatrogénica es de las causas más frecuentes. La CSA es un farmaco introducido por Borel en terapeútica en 1976 y actualmente con un uso más multidisciplinario (en transplantes, enfermedades autoinmunes, patología tumoral). En el presente trabajo de investigación hacemos un estudio clínico histopatológico y con análisis digital de imagen de 30 paciente transplantados de riñón de ls pro...

  11. Hiperplasia gingival inducida por Ciclosporina A en transplantes renales : estudio cl??nico, morfom??trico inmunohistoqu??mico y ultraestructural

    OpenAIRE

    Mesa, Francisco

    1992-01-01

    El aumento en el tama??o de la encia es uno de los principales signos de enfermedad gingival, y la hiperplasia iatrog??nica es de las causas m??s frecuentes. La CSA es un farmaco introducido por Borel en terape??tica en 1976 y actualmente con un uso m??s multidisciplinario (en transplantes, enfermedades autoinmunes, patolog??a tumoral). En el presente trabajo de investigaci??n hacemos un estudio cl??nico histopatol??gico y con an??lisis digital de imagen de 30 paciente transplantados de ri???...

  12. Estudio comparativo de la respuesta inmune inducida por dos tipos de vacunas (VLP e inactivada) frente al virus de la lengua azul en el ganado ovino

    OpenAIRE

    Pérez de Diego Camacho, Ana Cristina

    2012-01-01

    La Lengua azul (LA) es una enfermedad infecciosa, no contagiosa, transmitida por jejenes del género Culicoides que afecta a diferentes especies de rumiantes, tanto domésticos, como silvestres. Los animales que desarrollan la enfermedad son fundamentalmente las ovejas, pudiéndose alcanzar altas tasas de morbilidad y mortalidad. La enfermedad de la LA no afecta al ser humano, pero cobra gran importancia debido a su elevado poder de transmisión y difusión provocando graves consecuencias socioeco...

  13. Cambios en el patrón de arritmias cardíacas inducidas por reperfusión, en presencia de fármacos antioxidantes

    OpenAIRE

    Aguiar Damaris, Muriel; Román, Bárbara; Salas, Margarita Ana; Vittone, Leticia; Mundiña-Weilenmann, Cecilia; Said, Matilde

    2016-01-01

    Las arritmias ventriculares que aparecen durante la reperfusión (R) luego de la isquemia del miocardio, son la primera causa de muerte asociada al infarto de miocardio. Estas arritmias varían en gravedad desde latidos ventriculares prematuros (LVP) hasta episodios de taquicardia (TAV) o fibrilación ventricular. A nivel celular, estos trastornos del ritmo pueden estar favorecidos por pérdidas espontáneas de calcio desde el canal liberador de calcio, receptor de rianodina cardíaco (RyR2) cuya f...

  14. Obstrucción respiratoria alta secundaria a distonía laríngea recurrente inducida por haloperidol y ziprasidona.

    OpenAIRE

    Cruzado, Lizardo; Rivera-Encinas, María Teresa; Revilla-Zúñiga, Joshep A.; Sánchez-Fernández, Miguel

    2015-01-01

    La distonía aguda por antipsicóticos es un efecto extrapiramidal frecuente con el uso de estos medicamentos y, aunque su prevalencia es menor con el uso de antipsicóticos atípicos, no dejan de suscitarse casos de dichasreacciones adversas. Entre ellas, la distonía laríngea es un problema que requiere tratamiento de urgencia y que incluso acarrea riesgo mortal. Reportamos el caso de una paciente joven de sexo femenino y con diagnóstico de esquizofrenia paranoide, quien se presentó a nuestro se...

  15. Compactación inducida por el tránsito vehicular sobre un suelo en producción hortícola Induced compaction by the vehicular traffic in a soil for horticultural crop production

    Directory of Open Access Journals (Sweden)

    Antonino Marcelo Terminiello

    2000-01-01

    Full Text Available Se realizaron ensayos en campo con el objeto de caracterizar el estado de compactación de un suelo en producción hortícola inducida por el tránsito, luego del desarrollo del ciclo de un cultivo de repollo (Brassica oleracea L. grupo capitata y su incidencia sobre el rendimiento. Se efectuaron determinaciones de resistencia a la penetración, densidad aparente y humedad gravimétrica sobre el suelo y biomasa aérea al finalizar el ciclo del cultivo en los sectores de mayor y menor número de pasajes de vehículos. Los valores de resistencia a la penetración fueron de 1,7 y 1,3 MPa, significativamente mayores para el tratamiento de más de 7 y 3 pasadas respectivamente en el rango de profundidad de 0-100 mm . No se manifestaron diferencias en el parámetro densidad aparente en la totalidad del perfil. Se encontraron diferencias estadísticamente significativas en biomasa aérea, para el tratamiento de 3 pasadas (1902.6 g planta-1, en relación al de mas de 7 pasadas (1447,9 g planta-1. El pasaje repetido sobre los surcos originan incrementos en la resistencia a la penetración a nivel superficial. El peso fresco y la materia seca del cultivo son afectados por el número de pasadas de los tractores y máquinas agrícolas.Field test were carried out with the objective of characterizing the state of compaction in horticultural soil induced by traffic, after the development of a cabbage crop (Brassica oleracea L. group capitata cycle, and its incidence on yield. Measurements of penetration resistance, bulk density, and moisture content in soil were made and aeread biomass at the end of the cycle crop in sectors with larger and smaller number of vehicles passes. Values of penetration resistance of 1.7 and 1.3 MPa were found for treatment with more than 7 passes and 3 passes respectively in the depth range of 0-100 mm. No significant differences were found in bulk density parameter in the entire soil profile. Statistically significant differences

  16. Efecto antioxidante del extracto acuoso de propóleos sobre la hepatotoxicidad inducida por el octilfenol en ratas macho Antioxidant effect of aqueous extract of propolis on hepatotoxicity induced by octylphenol in male rats

    Directory of Open Access Journals (Sweden)

    Eman M Saleh

    2012-12-01

    Full Text Available El 4-terc-octilfenol (4-terc-OP es un alquilfenol que afecta a la salud humana mediante la estimulación de la producción de radicales libres. El extracto acuoso de propóleos es un producto natural rico en favonoides que tienen actividad antioxidante. Este estudio fue diseñado para investigar la capacidad del extracto de propóleos de reducir la hepatotoxicidad inducida por el 4-terc-OP en ratas macho. Los animales fueron asignados a 5 grupos y tratados durante 6 semanas. Grupo 1: control; grupo 2: 100 mg de 4-terc-OP/kg/día; grupo 3: 100 mg de extracto de propóleos/kg/día; grupo 4: 100 mg de 4-terc-OP/ kg/día más 100 mg de extracto de propóleos/kg/día, grupo 5: 100 mg de 4-terc-OP/kg/día durante 6 semanas, seguidos de 100 mg de extracto de propóleos/kg/día durante 6 semanas. El grupo 4-terc-OP mostró niveles signifcativamente elevados de AST, ALT, ALP, GGT, bilirrubina, creatinina, urea, lípidos totales, colesterol total, triglicéridos, LDL-C y MDA, con una disminución signi-fcativa de proteínas totales, albúmina, globulina, HDL-C, la capacidad antioxidante total, SOD, CAT y GST, en comparación con el grupo control. La administración de extracto de propóleos, ya sea solo o combinado con 4-terc-OP redujo la hepatotoxicidad inducida por 4-terc-OP. Los estudios de fragmentación del ADN apoyan el efecto deletéreo observado por el tratamiento con 4-terc-OP y el efecto protector del extracto de propóleos, sobre las proteínas y las enzimas celulares hepáticas. Los resultados histopatológicos revelaron la hepatotoxicidad por 4-terc-OP y efecto protector inducido por el extracto de propóleos. En conclusión, el extracto de propóleos podría reducir el daño hepático y los efectos celulares de toxicidad en las células del hígado inducidos por 4-terc-OP.4-tertiary-octylphenol (4-tert-OP is an alkylphenol that affects human health by stimulating free radical production. Aqueous propolis extract is a natural product rich in

  17. El ensayo de micronúcleos como medida de inestabilidad genética inducida por agentes genotóxicos The cytogenetic assay as a measure of genetic instability induced by genotoxic agents

    Directory of Open Access Journals (Sweden)

    M. Zalacain

    2005-08-01

    Full Text Available La integridad genética de la población humana se encuentra comprometida por la gran actividad industrial; por lo que es importante determinar qué se conoce como un nivel "aceptable" de daño genético y realizar ensayos de genotoxicidad de manera rutinaria en poblaciones de riesgo. Los micronúcleos son cuerpos citoplasmáticos de naturaleza nuclear, se corresponden con material genético no incorporado correctamente a las células hijas durante la división celular, reflejan aberraciones cromosómicas y se originan por roturas cromosómicas, por errores durante la replicación y posterior división celular del ADN y/o por la exposición a agentes genotóxicas. Existen factores capaces de influir o modificar el número de micronúcleos presentes en una célula (edad, género, vitaminas, tratamientos médicos, exposición diaria a agentes genotóxicos, etc.. El ensayo citogenético para la detección de micronúcleos (CBMN: cytokinesis-block micronucleus se basa en la utilización de un agente químico, denominado citocalasina-B capaz de impedir la citocinesis permitiendo la división nuclear proporcionando a las células un aspecto de células binucleadas monodivididas. El recuento de micronúcleos se realiza sobre 1.000 células binucleadas y la muestra de partida puede variar aunque lo óptimo es el uso de linfocitos aislados de sangre periférica. El ensayo de micronúcleos está considerado como un ensayo práctico, universalmente validado y accesible tecnológicamente, útil para evaluar la inestabilidad genética inducida por agentes genotóxicos.Human genetic integrity is compromised by the intense industrial activity, which emphasizes the importance to determine an "acceptable" genetic damage level and to carry out routine genotoxicity assays in the populations at risk. Micronuclei are cytoplasmatic bodies of nuclear origin which correspond to genetic material that is not correctly incorporated in the daughter cells in the cellular

  18. Alteraciones histológicas y neuroquímicas inducidas en el cuerpo estriado por la exposición a sulfonato de perfluoroctano (PFOS

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    A. Lafuente

    2013-01-01

    dosis de 1 mg/Kg/día, aumentando con la de 3 mg/Kg/día. PFOS induce también una degeneración celular dosis-dependiente, evidenciada por un aumento de la basofilia. Tras la exposición a dosis elevadas de PFOS (3 y 6 mg/Kg/día se observa también satelitosis acúmulo de los oligodendrocitos en este mismo tejido. Las alteraciones neuroquímicas e histológicas observadas en los animales tratados con PFOS podrían estar relacionadas con disfunciones a nivel cognitivo y emocional, así como con diversas patologías neurodegenerativas como la enfermedad de Parkinson.

  19. Aspergilosis pulmonar secundaria a neutropenia inducida por metimazol: reporte de un caso Pulmonary aspergillosis due to methimazole-induced neutropenia: a case report

    Directory of Open Access Journals (Sweden)

    Miguel E. Pinto

    2012-06-01

    Full Text Available Se reporta el caso de una paciente de 48 años de edad con diagnóstico reciente de enfermedad de Graves, quien acudió a emergencia por presentar fiebre, palpitaciones y dolor faríngeo. Su tratamiento regular incluía metimazol. Al ingreso, los análisis mostraron TSH suprimido, T4 libre elevado y neutropenia. La paciente fue hospitalizada, se administraron antibióticos y factor estimulante de colonia. Después de diez días de tratamiento, la paciente presentó leucocitosis, fiebre y hemoptisis. La tomografía de tórax mostró una cavidad con múltiples nódulos en el lóbulo superior derecho. Los cultivos fueron positivos a Aspergillus fumigatus y Aspergillus flavus. Se inició tratamiento con anfotericina B y luego se cambió a voriconazol, a pesar de lo cual no hubo mejoría del cuadro. La paciente falleció por falla multiorgánica.A 48-year old woman with a recent diagnosis of Graves’ disease arrived at the emergency room with fever, palpitations, and a sore throat. Her regular treatment included methimazole. On admission, laboratory results showed suppressed TSH, elevated free thyroxine, and neutropenia. She was admitted and started on antibiotics and granulocyte-macrophage colony stimulating factor (gm-csf. After ten days, the patient developed leukocytosis, fever, and hemoptysis. Chest CT scan showed a lung cavity with multiple nodules in the upper right lobe. Cultures from a lung biopsy were positive for Aspergillus Fumigatus and Aspergillus Flavus. Amphotericin B was started but then switched to voriconazole, with both treatments failing to result in clinical improvement. The patient died of multi-organ failure.

  20. Tratamiento de agua potable por filtración inducida en una laguna costera en el sur de Brasil Bank filtration drinking water treatment in a costal lagoon in south Brazil

    Directory of Open Access Journals (Sweden)

    Luis Guillermo Romero Esquivel

    2012-12-01

    Full Text Available La filtración inducida (FI consiste en obtener agua potable de pozos situados en acuíferos de aluvión u otro tipo de depósitos no consolidados conectados hidráulicamente con una fuente de agua superficial. La posibilidad de aplicar esta técnica en las riberas de la laguna Lagoa do Peri, Brasil, se evaluó a nivel piloto. Por medio de observación y de análisis granulométricos se determinó que el fondo de la laguna y el acuífero aledaño presentan una textura arenosa. Además, ensayos de permeámetro de carga constante, de tubo de carga variable y de bombeo, mostraron que la conductividad hidráulica en las mismas zonas se encuentra cercana a 10-4 m/s, misma magnitud encontrada en otras latitudes donde la FI se aplica con éxito. El agua captada en un pozo a 20 m de la Lagoa do Peri presentó valores de turbidez y color aparente acordes con los patrones de calidad locales. Se observó un aumento en la dureza y la alcalinidad, atribuido a la erosión de los materiales del subsuelo, sin llegar a superar lo estipulado en la legislación. Finalmente, el agua producida por la FI mostró ser de mejor calidad en términos de turbidez y color aparente que el agua de la laguna tratada por filtración directa en una estación de tratamiento (ETA ubicada en el lugar. El agua producida por la FI presentó condiciones anóxicas que harían necesario el postratamiento por aireación y filtración, proceso en el cual se podría aprovechar la infraestructura de la ETA existente.Bank filtration (BF consists in obtaining drinking water from wells in alluvial aquifers or other unconsolidated deposits hydraulically connected with a surface water source. The possibility of applying this technique was evaluated in a pilot scale on the banks of the Lagoa do Peri lagoon, Brazil. Observation and grain size analysis showed that the bottom of the lagoon and the adjacent aquifer have sandy texture. In addition, tests of constant head permeameter, standpipe falling

  1. Osteonecrosis de los maxilares inducida por bifosfonatos: prevención y actitud terapéutica Bisphosphonate induced osteonecrosis of the jaws: prevention and therapeutic approach

    Directory of Open Access Journals (Sweden)

    F.J. Barrientos Lezcano

    2007-10-01

    Full Text Available Introducción. La osteonecrosis maxilar o mandibular por bifosfonatos puede convertirse en una epidemia debido a la amplia difusión de estos fármacos entre la población. Material y método. Se muestra un protocolo para la prevención y el tratamiento de esta enfermedad. Se presentan tres casos de osteonecrosis maxilar/mandibular. Resultados. Es difícil lograr una curación completa; sin embargo es posible detener la progresión de la enfermedad. Discusión. La cirugía y la suspensión de la terapia con bifosfonatos han demostrado poca utilidad. Los antibióticos y los enjuagues con clorhexidina son las únicas medidas eficaces. Conclusiones. Es imprescindible una planificación adecuada previa a la instauración del tratamiento con bifosfonatos. Ante una osteonecrosis establecida, la actitud debe ser conservadora.Introduction. Bisphosphonate-induced osteonecrosis of the jaws might reach epidemic proportions due to the widespread use of this therapy. Materials and methods. A protocol for prevention and treatment of this pathology is shown. Three clinical cases are reported. Results. It is quite difficult to reach restitutio ad integrum, but stopping the progress of the disease is possible. Discussion. Surgical treatment and cessation of bisphosphonate therapy are of no use. Only antibiotics and oral chlorhexidine have shown some benefits. Conclusions. An accurate preventive attitude is mandatory prior to undergoing bisphosphonate therapy. If osteonecrosis of the jaws is present, management should be conservative.

  2. Respuesta inmune y expresión de genes en el camarón blanco (Litopenaeus vannamei inducida por inmunoestimulantes microbianos

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    Antonio Luna-González

    2013-11-01

    Full Text Available Se realizó un bioensayo de 26 días para evaluar el efecto inmunoestimulante de bacterias ácido lácticas y levaduras (MI, adicionadas en el alimento, en Litopenaeus vannamei. Los tratamientos del bioensayo se realizaron por triplicado: I dieta control (Camaronina®; II MI en alimento, diario; III MI en alimento, cada tres días y; IV MI en alimento, cada seis días. Los camarones sólo eran libres de WSSV. Para el estudio del sistema inmune se hizo un conteo total de hemocitos, se determinó bioquímicamente la concentración de anión superóxido, y la actividad de la fenoloxidasa. También se estudió la expresión semicuantitativa de seis genes del sistema inmune, utilizando la técnica de RT-PCR. No hubo aumento significativo en el crecimiento y la supervivencia, el conteo total de hemocitos, la concentración de la proteína total en plasma y hemocitos, y la concentración del anión superóxido. La actividad de la fenoloxidasa en plasma en el tratamiento IV fue significativamente mayor que en los tratamientos I, II y III. La fenoloxidasa del SLH (proFO en el tratamiento IV fue significativamente mayor que en los tratamientos I y III. La MI provocó una sobreexpresión significativa de los genes que codifican para la profenoloxidasa (tratamiento IV, lisozima (tratamiento III y transglutaminasa (tratamiento II, con respecto a los animales no tratados (control. La mezcla de inmunoestimulantes microbianos puede aumentar la resistencia de L. vannamei contra patógenos en los cultivos.

  3. Evaluación endoscópica de hemorragia pulmonar inducida por el ejercicio en equinos de polo Endoscopic evaluation of Exercise Induced Pulmonary Hemorrhage in Polo Ponies

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    G. MORAN

    2003-01-01

    Full Text Available El objetivo de este estudio fue determinar la presencia de Hemorragia Pulmonar Inducida por el Ejercicio (HPIE mediante el examen endoscópico en caballos de polo. Para ello se emplearon 39 equinos en competencia, ubicados en la Zona Central de Chile. Los equinos fueron divididos en dos grupos, según las temporadas de competencia (hasta con 2 temporadas y 3 o más temporadas, y además se clasificaron según sexo (macho y hembra, independientemente del número de temporadas de competencia. Se efectúo un examen endoscópico de las vías aéreas, el cual se realizó con el animal en reposo, 2 a 4 horas post-competencia. Se consideraron positivos todos los equinos que tuviesen presencia de sangre en el tracto respiratorio superior hasta la carina traqueal. Los datos obtenidos se analizaron a través de un modelo de asociación e independencia de X² cuadrado, con un nivel de significación pThe objective of the present study was to determine the presence of Exercise Induced Pulmonary Hemorrhage (EIPH by endoscopic examination in polo ponie after competition. Thirty nine polo horses in training were used in this study. The animal were classified by the number of polo seasons they had played (two seasons and three or more and by sex independently of the number of seasons played. An endoscopic evaluation of the respiratory system was carried out 2 to 4 hours after exercise in all horses. All animals with blood in the upper respiratory tract were considered to be positive. The data obtained were analyzed through a model of association and independence of X², with a level of significance p<0.05. The results obtained showed that 46% of the animals were positive for EIPH and in terms of sex, 63.6% of the males and 39.2% of the females were positive. The individuals with three or more seasons and two seasons were 60% and 31.5% positive, respectively. The statistical analyses showed no significance between EIPH number of polo seasons and sex in the polo

  4. Efectos de la alcalosis metabólica inducida por la dieta en el rendimiento anaeróbico de alta intensidad Effects of the metabolic alkalosis induced by the diet in the high intensity anaerobic performance

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    O. Ríos Enríquez

    2010-10-01

    Full Text Available Objetivos: El propósito principal de este estudio es comparar el efecto de una alcalosis y acidosis inducidas por la dieta sobre el rendimiento en un esfuerzo anaeróbico láctico mantenido. Métodos: Para ello, trece sujetos activos se sometieron de forma cruzada a sendas dietas durante dos días y medio. Inmediatamente después realizaron una prueba de esfuerzo anaeróbica láctica máxima de estado estable hasta el agotamiento sobre cicloergómetro a 250 W. Resultados: La valoración de las dietas mostró una diferencia significativa en la excreción renal neta de ácidos (NAE estimada, así como un déficit calórico del 54% en la dieta alcalinizante, debido principalmente a una ingesta reducida de hidratos de carbono. En un 83% de los sujetos aumentó el pH urinario tras la dieta alcalinizante. El 77% incrementó sus niveles de lactato en sangre en la prueba tras la dieta alcalina. Los tiempos hasta la extenuación durante la prueba mejoraron o se mantuvieron en un 58% de los sujetos, siendo las mujeres las que mejor respondieron a la dieta con un 83% de casos. Conclusiones: Parece haber evidencias de mejora de rendimiento en esfuerzos de tipo anaeróbico láctico hasta el agotamiento de 60 s a 2 min de duración tras consumir una dieta con potencial alcalinizante.Objectives: The purpose of this study is to compare the effects of two diets, one acidifier and the other alkalizer, on the sport performance in an extreme anaerobic stress test. Methods: For that purpose thirteen individuals were subjected to two such diets in a crossed test for two and a half days. Immediately after, they were tested in a maximum lactic anaerobic stress test of stable state to exhaustion on an ergo-cycle at 250W. Results: The assessment of the diets yielded a significant difference in the estimated NAE (net acid excretion and a caloric deficit of 54% on the alkalizer diet, mainly due to a reduced ingestion of carbohydrates. The urinary pH increased by 83% for

  5. Tiroiditis autoinmune inducida por interferón en pacientes con infección por virus de la hepatitis C. Interferon-induced autoimmune thyroiditis in a patient with hepatitis C virus infection

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    Pinto, José L.; Miguel E. Pinto

    2011-01-01

    Se reporta el caso de un varón de 43 años de edad, sin antecedentes patológicos de importancia, que acudió por elevación asintomática de la alanino aminotransferasa (ALT). El paciente negó ser bebedor crónico de alcohol. Se hizo el diagnóstico serológico de infección activa por hepatitis C y la biopsia de hígado reveló inflamación crónica activa. Con estos resultados, se inició tratamiento con interferón-alfa y ribavirina. Durante el tratamiento de 48 semanas, el paciente presentó anticuerpos...

  6. Tiroiditis autoinmune inducida por interferón en pacientes con infección por virus de la hepatitis C. Interferon-induced autoimmune thyroiditis in a patient with hepatitis C virus infection

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    José L. Pinto

    2011-06-01

    Full Text Available Se reporta el caso de un varón de 43 años de edad, sin antecedentes patológicos de importancia, que acudió por elevación asintomática de la alanino aminotransferasa (ALT. El paciente negó ser bebedor crónico de alcohol. Se hizo el diagnóstico serológico de infección activa por hepatitis C y la biopsia de hígado reveló inflamación crónica activa. Con estos resultados, se inició tratamiento con interferón-alfa y ribavirina. Durante el tratamiento de 48 semanas, el paciente presentó anticuerpos antitiroideos positivos con variaciones en sus niveles de tirotropina (TSH y hormonas tiroideas. En el seguimiento postratamiento, el paciente continuó con hipertiroidismo por enfermedad de Graves. La tiroiditis autoinmune es una complicación frecuente del uso de interferón en pacientes con hepatitis C. En algunos casos se presenta como hipertiroidismo por enfermedad de Graves. Se debe evaluar la función tiroidea y los anticuerpos antitiroideos antes y durante el tratamiento con interferón.A 43 year old man presented with asymptomatic elevation of alanine aminotransferase (ALT and no relevant past history. The patient denied being a chronic alcohol drinker. Work-up revealed an active hepatitis C, and liver biopsy showed active inflammation. Treatment was started with interferon-alfa and ribavirin. During the 48 weeks of treatment, the patient developed positive thyroid antibodies with varying level of thyrotropin (TSH and thyroid hormones. At follow-up after treatment, the patient continued with hyperthyroidism due to Graves’ disease. Autoimmune thyroiditis is a common complication of using interferon in patients with hepatitis C. In some cases, it is presented as hyperthyroidism because of Graves’ disease. Thyroid function and thyroid antibodies should be evaluated before and during treatment with interferon.

  7. Cuidando de paciente com câncer de mama e osteonecrose mandibular induzida por bisfostonato: relato de experiência Cuidando de pacientes con cáncer de mama y osteonecrosis mandibular inducida por bisfosfonatos: relato de experiencia Providing care for patients with breast cancer and mandible ostheonecrosis induced by bisphosphonates: an experience report

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    Verônica Paula Torel de Moura

    2009-02-01

    Full Text Available OBJETIVO: Descrever as ações desenvolvidas pela enfermeira junto a uma paciente com câncer de mama e metástase óssea que apresentou necrose mandibular induzida pelo uso de bisfosfonato. RESULTADOS: As intervenções de enfermagem incluíram o ensino e reforço das orientações sobre higiene oral, destacando a escovação adequada, bochechos com solução antisséptica sem álcool, bem como sobre o controle da dor. CONCLUSÃO: Destaca-se a importância da atuação multiprofissional e da consulta de enfermagem no seguimento dessas pacientes para detecção precoce e controle dessa complicação.OBJETIVO: Describir las acciones de enfermería implementadas por la enfermera a una paciente con cáncer con metástasis ósea que presentó necrosis mandibular inducida por el uso de bisfosfonatos. RESULTADOS: Las intervenciones de enfermería incluyeron la enseñanza y el refuerzo de las orientaciones sobre la higiene oral, dando destaque al adecuado cepillado de los dientes, gárgaras con solución antiséptica sin alcohol y al control del dolor. CONCLUSIÓN: Es destacada el importancia de la actuación multiprofesional y de la consulta de enfermería en el seguimiento de esas pacientes, visando la detección temprana y el control de esa complicación.OBJECTIVE: To describe a nurse experience in providing care for a patient with cancer of the breast and bone metastasis who presented mandibular ostheonecrosis induced by the use of bisphosphonates. RESULTS: Nursing interventions included the re-enforcement of the guidelines for oral hygiene, highlighting the appropriate teeth-brushing technique, gargling with antiseptic solution without alcohol, as approach to pain management. CONCLUSION: There is a need for multidisciplinary and nursing consultations for early detection and control of potential complications.

  8. Detección precoz por Tomografía Computada Cuantitativa Multicorte de alteraciones en la densidad mineral ósea, inducidas por una dieta aterogénica, en un modelo experimental en ratas en crecimiento Multislice Quantitative Computed Tomography allozos early detectíon of bone mineral density alterations induced by atherogenic diet in a growing rat experimental model

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    Marcelo Joaquín Gubert

    2012-03-01

    Full Text Available Propósito. Demostrar la utilidad de la tomografía computada cuantitativa multicorte (QCT-MC en la detección precoz de alteraciones en la densidad mineral ósea (DMO mandibular, inducidas por una dieta aterogénica, en un modelo experimental en ratas en crecimiento. Materiales y Métodos. Ratas Wistar macho (n=16 al destete, loteadas por peso en 2 grupos: Control (C y experimental (E; peso promedio inicial sin diferencias significativas (p > 0,05; recibieron a libre demanda: C, dieta stock para roedores y E, dieta aterogénica por 3 semanas. Se monitorearon zoometría (peso y longitud corporales y consumo de dieta (g/100 g rata/día. A las 3 semanas en suero (mg/dL, se evaluó el perfil lipídico-lipoproteico: colesterol total (col-T, triglicéridos (TG, col HDL y noHDL, y la QCT-MC (Philips 64 CT, cuantificado con eFilm Workstation 2.1 de siete zonas mandibulares (ZM: n° 1 a 4, desde forámen mentoniano hacia mandibular; n° 5, proceso coronoide; n° 6, proceso condilar; n° 7, proceso angular. Se realizó análisis estadístico Pearson: correlación entre DMO de cada ZM y valor sérico de col-T (nivel de significación p 0,05. Los coeficientes de correlación (r y respectivos niveles de significación (p mostraron, en cinco de siete ZM, ser significativos: ZM 1: -0,580 (p = 0,019, ZM 2: -0,709 (p = 0,002, ZM 3: -0,635 (p = 0,008, ZM 5: -0.674 (p = 0,004, ZM 6: -0,564 (p = 0,023. Conclusiones. Estos resultados sugieren que la QCT-MC es un método de diagnóstico por imágenes que permite detectar precozmente alteraciones inducidas por una dieta aterogénica en la arquitectura ósea de la mandíbula. La correlación inversa entre la DMO y el col-T indicaría una asociación entre el consumo de una dieta aterogénica y posibles disfunciones témporo-mandibulares.Purpose. To demónstrate the utility of Multislice Quantitative Computed Tomography (MS-QCT in the early detection of mandibular bone mineral density (BMD alterations induced by an

  9. Rabdomiólise induzida por exercício e risco de hipertermia maligna: relato de caso Rabdomiólisis inducida por ejercicio y riesgo de hipertermia maligna: relato de caso Exercise-induced rhabdomyolysis and risk for malignant hyperthermia: case report

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    Ricardo Barreira Uchoa

    2003-02-01

    ólica, coagulación intravascular diseminada, síndrome de incomodidad respiratoria aguda y rabdomiólisis. Ha sido sugerido que hipertermia maligna, choque térmico y rabdomiólisis inducida por ejercicio son síndromes fuertemente relacionadas. El objetivo de este relato es describir un caso de rabdomiólisis fulminante después de ejercicio físico y la correlación del cuadro con hipertermia maligna. RELATO DEL CASO: Hombre de 32 años presentó mal estar seguido de síncope después de correr 2.350 m en una prueba de aptitud física. Fue llevado al hospital, evoluyó con insuficiencia respiratoria, bradiarritmia, hipotensión arterial y parada cardiocirculatoria. Fue reanimado, quedó comatoso, con importante rigidez muscular, choque persistente, disturbio de coagulación, acidosis metabólica, hiperpotasemia, evoluyendo para óbito en menos de 24 horas. La autopsia reveló edema agudo de pulmón, coagulación intravascular diseminada e insuficiencia renal aguda consecuente a la rabdomiólise. CONCLUSIONES: Ha sido sugerido que la rabdomiólisis inducida por ejercicio e hipertermia maligna son síndromes fuertemente relacionadas. El paciente evoluyó para óbito antes de cualquier investigación específica para hipertermia maligna. No entanto, es importante pesquisar la susceptibilidad para este síndrome en sus familiares a fin de evitar eventos anestésicos con potencial riesgo para la vida.BACKGROUND AND OBJECTIVES: Rhabdomyolysis is a skeletal muscle injury with cell components' release to plasma. Exhaustive exercise, especially in non-conditioned individuals, may result in severe morbidity such as hyperkalemia, metabolic acidosis, disseminated intravascular coagulation, acute respiratory distress syndrome and rhabdomyolysis. It has been suggested that malignant hyperthermia, thermal shock and exercise-induced rhabdomyolysis are closely related syndromes. This report aimed at describing a case of fatal rhabdomyolysis after physical exercise and its correlation with

  10. Papel de la fosfolipasa A2 citosólica de grupo IVA en la diferenciación adipocítica y en el desarrollo de obesidad inducida por dieta alta en grasa

    OpenAIRE

    Peña, Lucía

    2014-01-01

    Tesis Doctoral presentada por María Lucía Peña Moreno para optar al grado de Doctor por la Universidad de Valladolid, Facultad de Medicina (Departamento de Bioquímica y Biología y Fisiología); Instituto de Biología y Genética Molecular (IBGM).-- Sujeta a Licencia Creative Commons.

  11. Há uma associação entre anti-inflamatórios não-esteroides e nefropatia induzida por contraste? ¿Hay una asociación entre antiinflamatorios no esteroides y nefropatía inducida por contraste? Is there an association between non-steroidal anti-inflammatory drugs and contrast nephropathy?

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    Luciano Passamani Diogo

    2010-12-01

    Full Text Available FUNDAMENTO: A associação entre o uso de anti-inflamatórios não-esteroides (AINEs e insuficiência renal aguda ou crônica é bem documentada, mas evidências sobre a associação entre AINEs e nefropatia induzida por contraste (NIC não são encontradas na literatura. OBJETIVO: Avaliar uma possível associação entre AINEs e NIC. MÉTODOS: Em um estudo de coorte, através da entrevista clínica de pacientes que foram submetidos à cateterização cardíaca, analisamos o uso de AINEs e sua associação com desenvolvimento de NIC, através da alteração dos níveis de creatinina sérica ou taxa de filtração glomerular em 48 ou 72 horas. RESULTADOS: No período de julho de 2005 a julho de 2006, 236 pacientes foram incluídos no estudo, dos quais 29 foram posteriormente excluídos. A incidência de NIC foi 10,37% (20 de 207 e 42% dos pacientes estavam recebendo AINEs até o momento da avaliação. Não houve associação entre o uso de AINEs e o desenvolvimento de NIC com OR de 1,293; IC95% (0,46-4,2. O estudo detectou fatores de risco conhecidos para o desenvolvimento de NIC, tais como diabete, com OR de 2,77; IC95% (1,05-7,47 e insuficiência renal crônica com OR de 3,48; IC95% (1,1-11,07 e também sugeriu uma ação protetora da hidratação com solução salina com OR de 0,166; IC95% (0,03-0,92. CONCLUSÃO: Com base nos dados obtidos, concluímos que não houve associação entre NIC e uso prévio de AINEs, pelo menos com um OR > 2,85, o qual nossa amostra detectou.FUNDAMENTO: La asociación entre el uso de antiinflamatorios no esteroides (AINEs e insuficiencia renal aguda o crónica está bien documentada, pero evidencias sobre la asociación entre AINEs y nefropatía inducida por contraste (NIC no son encontradas en la literatura. OBJETIVO: Evaluar una posible asociación entre AINEs y NIC. MÉTODOS: En un estudio de cohorte, a través de la entrevista clínica de pacientes que fueron sometidos a cateterismo cardíaco, analizamos el

  12. Clonidina por via venosa na técnica de hipotensão arterial induzida para timpanoplastias Clonidina por vía venosa en la técnica de hipotensión inducida para timpanoplastias Intravenous clonidine in the induced arterial hypotension technique for tympanoplasty

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    Renato Mestriner Stocche

    2003-08-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: A hipotensão arterial induzida é uma técnica eficaz para diminuir o sangramento durante atos cirúrgicos. A clonidina é um a2-agonista de ação central que já se mostrou segura em anestesia. O objetivo deste estudo foi verificar a eficiência da clonidina por via venosa como droga principal na hipotensão arterial controlada. MÉTODO: Participaram do estudo prospectivo e duplamente encoberto, 36 pacientes de ambos os sexos, estado físico ASA I e II, divididos aleatoriamente em três grupos de 12 pacientes que receberam medicação pré-anestésica: clonidina 3 µg.kg-1 (C3, clonidina 5 µg.kg-1 (C5 ou solução fisiológica a 0,9% (Controle 15 minutos antes da indução anestésica. A manutenção anestésica foi feita com isoflurano até a concentração máxima de 2%. Foram anotados a PA e a FC antes, com 1 e 5 minutos após a indução e a cada 5 minutos de anestesia. Pacientes há mais de 15 minutos recebendo isoflurano a 2% e que não apresentaram PAS menor que 80 mmHg receberam nitroprussiato de sódio para indução da hipotensão arterial. RESULTADOS: Três pacientes (25% no grupo C3 , um (8% no grupo C5 e oito (66% no grupo controle necessitaram de nitroprussiato de sódio. A dose total de nitroprussiato para se induzir hipotensão arterial no grupo controle foi maior do que nos grupos C3 e C5 (p JUSTIFICATIVA Y OBJETIVOS: A hipotensión arterial inducida es una técnica eficaz para diminuir el sangramiento durante actos quirúrgicos. La clonidina es un a2-agonista de ación central que ya se mostró segura en anestesia. El objetivo de este estudio fue verificar la eficiencia de la clonidina por vía venosa como droga principal en la hipotensión arterial controlada. MÉTODO: Participaron del estudio prospectivo y duplamente encubierto, 36 pacientes de ambos sexos, estado físico ASA I y II, divididos aleatoriamente en tres grupos de 12 pacientes que recibieron medicación pre-anestésica: clonidina 3

  13. Necrolisis epidérmica tóxica inducida por fármacos: Caso clínico Toxical epidermal necrolysis related to the use of drugs: Case report

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    L. Melloni Magnelli

    2008-12-01

    Full Text Available El Síndrome de Stevens Johnson (SSJ ha sido definido como un eritema multiforme vesiculobulloso de la piel y de otros órganos y se considera que es la etapa inicial de una reacción dérmica cuya forma más severa de presentación es la Necrolisis Epidérmica Tóxica (NET. Se manifiesta como una reacción sistémica inflamatoria aguda que involucra más del 30 % de la superficie corporal. Etiológicamente está relacionada con el uso de fármacos e un 60 % de los casos, sin embargo el herpes simple, infecciones por micoplasma y algunos factores genéticos, están considerados también como posibles desencadenantes. El SSJ presenta un pródromos catarral de entre 1 a 14 días de duración; el hallazgo clínico más importante son las lesiones máculo-papilares que se extienden centrípetamente y evolucionan a vesículas confluentes, afectando por lo general a la mucosa oral, conjuntival y al área genital. El SSJ evoluciona ocasionalmente a NET, que se caracteriza por dolor intenso y pérdida de la superficie epitelial, comprometiendo las funciones vitales del organismo, ocasionando un desequilibrio hidroelectrolítico, un compromiso renal y ocular, un gran catabolismo y un riesgo potencial de sepsis. Presentamos el caso de un menor de 3 años de edad, con antecedentes de cuadro viral; la hipertermia le ocasionó crisis convulsivas que fueron tratadas con Difenilhidantonína. Durante su hospitalización desarrolló un cuadro de SSJ/NET al cual sobrevivió. Enfatizamos la etiología multifactorial del síndrome en la que se combinaron sinergicamente medicamentos e infección como factores predisponentes del proceso.Stevens Johnson Syndrome (SJS has been defined as a vesiculobullous multiform erythema of the skin and other organs. It´s considered as initial stage of a dermal reaction in which the most severe form of presentation is Toxic Epidermal Necrolysis (TEN. This is an acute systemic inflammatory disease that involves more than 30% of

  14. Efeitos da administração de beta-bloqueador na remodelação ventricular induzida pelo tabagismo em ratos Efectos de la administración de betabloqueante en la remodelación ventricular inducida por el tabaquismo en ratas Effects of the administration of beta-blockers on ventricular remodeling induced by cigarette smoking in rats

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    Daniella R. Duarte

    2009-06-01

    Full Text Available FUNDAMENTO: O papel do sistema adrenérgico na remodelação induzida pelo tabagismo é desconhecido. OBJETIVO: Investigar a influência do propranolol na remodelação induzida pela exposição à fumaça de cigarro. MÉTODOS: Ratos foram alocados em três grupos: 1 C, n=10 - animais controle; 2 F, n=10 - animais expostos à fumaça de cigarro; 3 BB, n=10 - animais expostos à fumaça de cigarro e que receberam propranolol (40 mg/kg/dia. Após dois meses, os animais foram submetidos a estudo ecocardiográfico e morfométrico. Utilizou-se análise de variância (ANOVA de uma via (média ± desvio padrão ou Kruskal-Wallis (mediana e intervalo interquartil. RESULTADOS: O Grupo BB apresentou menor frequência cardíaca que o Grupo F (C = 358 ± 74 btm, F = 374 ± 53 bpm, BB = 297 ± 30; P = 0,02. O Grupo F apresentou maiores diâmetros diastólicos (C = 18,6 ± 3,4 mm/kg, F = 22,8 ± 1,8 mm/kg, BB = 21,7 ± 1,8 mm/kg; P = 0,003 e sistólicos (C = 8,6 ± 2,1 mmkg, F = 11,3 ± 1,3 mm/kg, BB = 9,9 ± 1,2 mm/kg; P = 0,004 do ventrículo esquerdo (VE, ajustado ao peso corporal (PC e tendência de menor fração de ejeção (C = 0,90 ± 0,03, F = 0,87 ± 0,03, BB =0,90 ± 0,02; P = 0,07 que o Grupo C. O Grupo BB apresentou tendência de menor relação VE/PC que o Grupo F (C = 1,94 (1,87 - 1,97, F = 2,03 (1,9-2,1 mg/g, BB = 1,89 (1,86-1,94; P = 0,09. CONCLUSÃO: A administração de propranolol atenuou algumas variáveis da remodelação ventricular induzida pela exposição à fumaça do cigarro em ratos.FUNDAMENTO: Aún se desconoce el rol del sistema adrenérgico en la remodelación inducida por el tabaquismo. OBJETIVO: Investigar la influencia del propranolol en la remodelación inducida por la exposición al humo del cigarrillo. MÉTODOS: Se dividieron las ratas en tres grupos: 1 C, n=10 - animales control; 2 F, n=10 - animales expuestos al humo de cigarrillo; 3 BB, n=10 - animales expuestos al humo de cigarrillo y que recibieron propranolol (40 mg

  15. Rutas de señalización celular involucradas en la plasticidad post-sináptica inducida por la activación de los canales de glutamato tipo NMDA en el hipocampo

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    Spinel Clara

    2005-07-01

    Full Text Available La apertura de los canales de glutamato tipo NMDA, gracias a la acción concomitante de las neuronas pre-sináptica y post-sináptica a nivel de las espinas dendríticas, induce a modificaciones de la fuerza y eficacia sinápticas en éstas, fenómeno mejor conocido como plasticidad sináptica. Las dos formas conocidas de plasticidad sinápticas son la potenciación a largo plazo (LTP y la depresión a largo plazo (LTD. Subyacen a ambos tipos de plasticidad modificaciones covalentes sobre las distintas proteínas que componen la densidad post-sináptica y, en caso de que la LTP se prolongue, una regulación activa de la transcripción y traducción de material genético. Así, la regulación activa de la fuerza y eficacia sináptica se debe al control activo sobre la tasa de inserción y remoción de los receptores de glutamato tipo AMPA, receptores encargados de la excitación rápida en el cerebro. Lo significativo de dicho evento en el hipocampo se debe a que éste está relacionado de manera estrecha con la memoria declarativa de los individuos, su memoria de reconocimiento y la memoria espacial, esta última mediada por la activación precisa y coordinada de las células de lugar que se encuentran en él.

  16. Estudio de tensiones inducidas en líneas de transmisión usando modelos de escala reducida sobre dos terrenos de diferente resistividad

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    Peralta Piernagorda, César Oswaldo

    2014-01-01

    En este proyecto se evaluó la magnitud de las tensiones inducidas en los sistemas de transmisión de energía eléctrica usando modelos a escala reducida debido a descargas atmosféricas a tierra: Se construyeron entre otros el canal de descarga del rayo a escala, línea aérea a escala y un generador de impulsos tipo rayo; se realizaron pruebas en planos de tierra metálicos y reales, se midieron las tensiones inducidas en la línea a escala por efecto de la corriente en el canal de rayo construido....

  17. Resistance exercise-induced microinjuries do not depend on 1or 3 minutes rest time interval between series. (Las microlesiones inducidas por el entrenamiento con cargas no dependen de los intervalos de descanso entre series de 1 o 3 minutos.

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    Rafael Pereira

    2008-10-01

    Full Text Available AbstractIn order to examine the effects of different rest intervals between sets on the muscle fiber integrity, 14 male subjects volunteered to participate in randomized crossover design methodology. All subjects completed 2 experimental training sessions. Both sessions consisted of 3 sets of 10 repetitions with 10 repetition maximum resistance bench press, cable pulldowns, military press, biceps curl, triceps curl, leg press, leg extension, and lying leg curls. The 2 experimental sessions differed only in the length of the rest period between sets and exercises: 1 session with a 1-minute and the other with a 3-minute rest period. the mechanical stress caused by the proposed training session cause similar damage in the muscle fibers do not depend of the 1 or 3 minutes of rest interval between series. ResumenEl propósito de ese estudio fue comparar los efectos de 2 diferentes períodos de descanso durante una sesión de entrenamiento con cargas en la integridad de la fibra muscular. Participaron de forma voluntaria 14 hombres en un estudio con diseño cruzado aleatorio. Todos los sujetos realizaron 2 sesiones de entrenamiento con cargas. Durante cada sesión, los sujetos completaban 3 series de 10 repeticiones máximas de press de banca, jalón en polea alta para dorsal, press militar, curl de bíceps con barra, extensión de tríceps trasnuca con mancuerna, prensa de piernas en máquina, extensión de rodillas en máquina, y flexión de rodillas en máquina. Las 2 sesiones experimentales diferían sólo en la longitud del período de descanso entre las series y los ejercicios: una sesión con 1 minuto y la otra con 3 minutos en los períodos de descanso. La tensión mecánica causada por las sesiones puede causar daños similares en las fibras musculares y no dependen de hacer 1 o 3 minutos de intervalo de descanso entre las series.

  18. Exercício físico previne alterações cardiometabólicas induzidas pelo uso crônico de glicocorticóides Ejercicio físico previene alteraciones cardiometabólicas inducidas por el uso crónico de glucocorticoides Exercise prevents cardiometabolic alterations induced by chronic use of glucocorticoids

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    Carlos Hermano da Justa Pinheiro

    2009-10-01

    , diabetes, dislipidemia, esteatosis hepática e hipertensión arterial. OBJETIVOS: Evaluar el efecto de la práctica regular de ejercicio físico aeróbico sobre las alteraciones cardiometabólicas inducidas por administración crónica de dexametasona (Dex - 0,5 mg/kg/día i.p en ratones. MÉTODOS: Se dividieron ratones Wistar machos (n = 24 en cuatro grupos: Grupo control; Grupo entrenado; Grupo tratado con Dex y Grupo tratado con Dex y entrenado. El entrenamiento físico (iniciado 72 horas después de la primera dosis de Dex se realizó 3 veces por semana, hasta el final del tratamiento. Al final de ese período, se realizaron las siguientes evaluaciones bioquímicas: glicemia en ayunas, test de tolerancia a la glucosa y análisis del perfil lipídico en sangre que incluyó colesterol total (CT, LDL-c, HDL-c, VLDL-c y triglicéridos (TG. También se evaluaron, el peso del músculo gastrocnemio, análisis histopatológico del hígado y los índices cardiometabólicos (CT/HDL-c, LDL-c/HDL-c y TG/HDL-c. RESULTADOS: Se observó hiperglicemia, menor tolerancia a la glucosa, elevación de CT, LDL-c, VLDL-c y TG, disminución del HDL-c, presencia de esteatosis hepática, hipotrofia muscular y elevación de los índices CT/HDL-c, LDL-c/HDL-c y TG/HDL-c en los animales tratados con Dex. El ejercicio físico redujo la hiperglicemia, mejoró la tolerancia a la glucosa, redujo la dislipidemia y previno la esteatosis hepática, la hipotrofia muscular y redujo los índices CT/HDL-c, LDL-c/ HDL-c ye TG/HDL-c. Con todo, no hubo efecto significativo del entrenamiento físico sobre el HDL-c. CONCLUSIÓN: El ejercicio físico aeróbico tiene efecto protector con las alteraciones cardiometabólicas inducidas por el uso crónico de glucocorticoides.BACKGROUND: Chronically, glucocorticoids induce adverse cardiometabolic alterations including insulin resistance, diabetes, dyslipidemia, liver steatosis and arterial hypertension. OBJECTIVES: To evaluate the effect of regular practice of aerobic

  19. Catalysis induced by radiations; Catalisis inducida por radiaciones

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez B, J.; Gonzalez J, J. C., E-mail: jaime.jimenez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    In Mexico is generated a great quantity of residuals considered as dangerous, for its capacity of corrosion, reactivity, toxicity to the environment, inflammability and biological-infectious potential. It is important to mention that the toxic compounds cannot be discharged to the sewerage systems and much less to the receiving bodies of water. The usual treatment that receives the dangerous residuals is the incineration and the bordering. The incineration is an efficient form of treating the residuals, but it can be dioxins source and benzofurans, being the phenol and chloro phenol the precursors of these compounds. At the present time the radiolytic degradation of organic compounds has been broadly studied, especially the 4-chloro phenol and of same form the photo catalysis of organic compounds. However the combination of both processes, called radio catalysis is barely reported. In this work the results of the experiments realized for to degrade the 4-chloro phenol by means of radio catalysis are reported. (Author)

  20. Inestabilidades electrohidrodinámicas inducidas por efecto corona

    OpenAIRE

    Vega Reyes, Francisco

    2002-01-01

    La Tesis trata del estudio de la inestabilidad "Rosetón", observada en líquidos poco conductores sometidos a descargan corona.El estudio con sta de una parte experimental y una teórica:* En el estudio experimental se describen las propiedades de la corri

  1. Expression of Early Light Induced Protein in Grapevine and Pea, under Different Conditions and its Relation with Photoinhibition Expresión de una Proteína inducida Tempranamente por Luz en Vid y Arveja Bajo Diferentes Condiciones y su Relación con la Fotoinhibición

    Directory of Open Access Journals (Sweden)

    Maritza Berti

    2012-09-01

    Full Text Available Early light induced proteins (ELIP are a type of proteins which are expressed before than other chloroplast proteins in the presence of light. These proteins have been studied in a large number of annual species such as pea (Pisum sativum L., barley (Hordeum vulgare L. and Arabidopsis sp. In perennials plants the studies about ELIPs are very scarce. The possible photoprotective function of the ELIPs has motivated the interest in investigating the presence of this type of proteins in a perennial plant such as grapevine (Vitis vinifera L. and if their characteristics differ from those found in annual plants. In this paper a comparative study was conducted on the ELIPs expression in grapevine and pea to investigate whether there are differences regarding to temperature and light intensity conditions necessary for maximum ELIP expression in each species and for studying in each case the relationship between ELIP expression and photoinhibition degree. The results of this study showed that the maximum ELIPs expression was reached from 25 °C and 1000 µmol PAR m-2 s-1 in both species. Above these values the expression remained constant. Regarding the temperature and light intensity effect on the photoinhibition degree, it was observed that temperature produced inverse relation in grapevine but no relation with pea. On the other hand, the light intensity produced direct relation in both grapevine and pea. The light intensity effect on ELIP expression suggests that these proteins may have a photorepairing role of the photosynthetic system, but the effect of temperature on the ELIP expression in short-term stress may be associated rather to the optimum conditions for their synthesis.Las proteínas tempranamente inducidas por luz (ELIP se expresan antes que otras proteínas del cloroplasto en presencia de luz. Estas proteínas han sido estudiadas en un gran número de especies anuales tales como arveja (Pisum sativum L., cebada (Hordeum bulgare L. y

  2. Alterações em variáveis motoras e metabólicas induzidas pelo treinamento durante um macrociclo em jogadores de handebol Alteraciones en las variables motoras y metabólicas inducidas por el entrenamiento durante un macro ciclo en jugadores de balonmano Changes in metabolic and motor performance variables induced by training in handball players

    Directory of Open Access Journals (Sweden)

    Juvenilson de Souza

    2006-06-01

    Full Text Available A monitoração do treinamento é uma prática comum no desporto. Essa monitoração deve ser baseada em testes específicos e que reflitam as adaptações às diversas etapas de treinamento, permitindo, assim, ajustes no programa deste. Assim, este estudo teve como objetivo analisar as alterações em variáveis motoras e metabólicas induzidas pelo treinamento durante um macrociclo em jogadores de handebol. Os atletas foram submetidos a um programa de preparação fundamentado no modelo de periodização proposto por Verkhoshanski(7 e adaptado por Oliveira(8. Foram estudados 11 jogadores de handebol, que realizaram treinamentos diários, na faixa etária de 20 a 32 anos, massa corporal média de 89,5 ± 10,4kg (70,2 a 105,1kg, e estatura média de 184,4 ± 6,7cm (171,8 a 198cm, filiados à equipe "UniFil/Londrina" do município de Londrina - PR. Os handebolistas foram submetidos a duas baterias de testes: a primeira no início do segundo macrociclo de treinamento e a segunda após 16 semanas, antecedendo o início da liga nacional. Para análise dos dados foi utilizado teste t para medidas repetidas com p La monitorización del entrenamiento es una práctica común en el deporte. Esa monitorización debe basarse en pruebas específicas y que reflejen las adaptaciones a las diversas etapas del entrenamiento, permitiendo así, ajustes en el programa del mismo. Así, este estudio ha tenido como objetivo analizar las alteraciones en las variables motoras y metabólicas inducidas por el entrenamiento durante un macro ciclo en jugadores de balonmano. Los atletas fueron sometidos a un programa de preparación basado en el modelo de periodicidad propuesto por Verkhoshanski(7 y adaptado por Oliveira(8. Fueron estudiados 11 jugadores de balonmano que realizaron entrenamiento diario, con edades entre 20 y 32 años, masa corporal media de 89,5 ± 10,4 kg (70,2 y 105,1 kg, y estatura media de 184,4 ± 6,7 cm (171,8 y 198 cm, afiliados al equipo "Uni

  3. Alteração da relação testosterona: cortisol induzida pelo treinamento de força em mulheres Alteración de la relación testosterona: cortisol inducida por el entrenamiento de fuerza en mujeres Alteration of testosterone: cortisol ratio induced by resistance training in women

    Directory of Open Access Journals (Sweden)

    Marco Carlos Uchida

    2004-06-01

    Full Text Available A razão entre a concentração de testosterona e cortisol (T:C é freqüentemente utilizada como indicativo do nível de estresse imposto pelo exercício. Alterações na concentração destes hormônios são responsáveis por modular diversas respostas induzidas pelo treinamento, como hipertrofia e ganho de força. O objetivo do presente estudo foi examinar a influência do protocolo de treinamento de força, conhecido como múltiplas-séries (MS, sobre o ganho de força, de resistência muscular localizada e a relação entre a concentração de hormônios catabólicos (cortisol e anabólicos (testosterona. Para testar esta hipótese cinco jovens do sexo feminino com um ano de experiência em treinamento de força foram submetidas ao protocolo MS. As amostras de sangue foram coletadas antes e imediatamente após o exercício, no primeiro dia e após oito semanas de treinamento. Os testes de 1-RM e de repetições máximas foram realizados também no início e ao final das oito semanas de treinamento de força. Não foram observadas alterações na massa corporal, no IMC, na percentagem de massa gorda e na força máxima (1-RM no supino, no agachamento e na rosca direta. O número de repetições máximas a 50% de 1-RM foi aumentado apenas para o supino (p La razón entre testosterona y cortisol (T:C es frecuentemente utilizada como indicador del nivel de stress impuesto por el ejercicio. Las alteraciones de las concentraciones de estas hormonas son las responsables por modular diversas respuestas inducidas por el entrenamiento, como son la hipertrofia y el aumento de la fuerza. El objetivo del presente estudio fué examinar la influencia del protocolo de entrenamiento de fuerza, conocido como series multiples (MS, sobre la ganancia de fuerza, la resistencia muscular localizada y la relación entre las concentraciones de las hormonas catabólicas (cortisol y anabólicas (testoterona. Para testar esta hipótesis, cinco jovenes del sexo feminino

  4. Reação cutânea grave induzida por carbamazepina no tratamento da neuralgia pós-herpética: relato de caso Reacción cutánea grave inducida por la carbamazepina en el tratamiento de la neuralgia postherpética: relato de caso Severe carbamazepine-induced cutaneous reaction in the treatment of post-herpetic neuralgia: case report

    Directory of Open Access Journals (Sweden)

    João Batista Santos Garcia

    2010-08-01

    da carbamazepina, que deve sempre ser supervisionado, especialmente em idosos.JUSTIFICATIVA Y OBJETIVOS: El herpes zoster tiene como principal complicación la neuralgia postherpética (NPH. Para su tratamiento se usa la carbamazepina (CBZ, un anticonvulsivo bien tolerado, pero que sin embargo está a menudo asociado a reacciones cutáneas graves, como por ejemplo, el síndrome de Stevens-Johnson (SSJ y la necrólisis epidérmica tóxica (NET. El objetivo de este trabajo es relatar un caso de SSJ/NET secundario al uso de CBZ en paciente con NPH. RELATO DEL CASO: Paciente del sexo femenino, con dolor continuo e intenso en la región torácica y dorso, ardor, punzada, descarga eléctrica, alteración de fuerza del miembro superior ipsilateral y sudoración. Presentaba lesiones de postillas y eritemas en la región dorsal del tórax, con alodinia y disestesias en el dermatoma acometido. Se inició CBZ 300 mg.día-1, amitriptilina (AMT12,5 mg por la noche e infiltración con anestésico local en la región afectada. Después de 15 días, el paciente decía sentir un fuerte malestar, fiebre, dolores musculares y artralgias con rash cutáneo ligero e inespecífico. Se le retiró la carbamazepina inmediatamente. Una semana después fue ingresado con urticaria y exantema generalizados, erupciones cutáneas eritematosas, burbujas y marcas purpúricas por todo el cuerpo. La impresión era de SSJ/NET inducida por carbamazepina. Hubo un progresivo empeoramiento del cuadro, con aumento del número y del tamaño de las lesiones cutáneas, además de rash eritematoso macular generalizado, áreas de necrosis y erosiones simétricas de la epidermis en la cara, cuello, tórax, dorso y miembros, llegando a más del 50% del área de superficie, además de la involucración de la mucosa bucal, conjuntival y genital con erosiones vesiculares. Presentó un empeoramiento funcional progresivo, evolucionando con choque séptico y fracaso multiorgánico, lo que produjo finalmente su deceso

  5. Lipoarabinomanano (LAM de Mycobacterium spp: Respuesta inmune inducida en terneros

    Directory of Open Access Journals (Sweden)

    A. Jolly

    2006-12-01

    Full Text Available La paratuberculosis es una enfermedad que afecta al ganado vacuno cuyo agente etiológico es el Mycobacterium avium subespecie paratuberculosis. El LAM es el principal componente antigénico de superficie de las micobacterias, y se lo considera de relevancia en la patogenia de las enfermedades que éstas causan. Un extracto enriquecido en LAM fue obtenido a partir de un cultivo de Mycobacterium spp. y empleado para inocular terneros. Se evaluó en ellos la respuesta inmune humoral y celular inducida por la vacunación. Los resultados de este estudio demuestran que el extracto enriquecido en LAM resultó ser inmunogénico en todos los animales inoculados, obteniéndose títulos considerables de anticuerpos específicos, sin generar falsos positivos a la prueba de intradermorreacción con el derivado proteico purificado utilizado para el diagnóstico de la tuberculosis bovina. Estos hallazgos justifican continuar el trabajo en esta línea intentando finalmente establecer si el LAM es un candidato potencial para la elaboración de una vacuna a subunidades contra la paratuberculosis bovina.Paratuberculosis is a chronic enteric disease affecting cattle. The causative agent is Mycobacterium avium subspecies paratuberculosis. LAM is the main antigenic component of mycobacterial surface, and it is considered a key virulence factor involved in its pathogenicity. A LAM-enriched extract obtained from a culture of Mycobacterium spp. was prepared with incomplete Freund's adjuvant for calves inoculation. Specific antibodies response and delayed-type hypersensitivity to intradermal injection of purified protein derivative antigen (PPD from Mycobacterium bovis were then evaluated in inoculated animals. Our results demonstrate that anti-LAM antibodies can be successfully obtained in calves immunized with LAM-enriched extract, without generating cross-reaction with PPD of M. bovis. This work could represent the initial step in order to determine the relevance of

  6. Ototoxicidad por medicamentos

    OpenAIRE

    Mercado M,Víctor; Burgos S,Rodolfo; Muñoz V,Claudio

    2007-01-01

    Se define ototoxicidad a las perturbaciones transitorias o definitivas de la función auditiva, vestibular, o de las dos a la vez, inducidas por sustancias de uso terapéutico¹. Son muchos los trabajos de investigación que se han dedicado ha este tema quedando aun dudas por resolver debido a las complejas consecuencias donde está envuelto el daño cocleovestibular. El propósito de esta revisión, es presentar las últimas teorías que tratan de explicar desde el punto de vista de la farmacociónétic...

  7. Lycopene mediated modulation of 7,12 dimethlybenz (A anthracene induced hepatic clastogenicity in male Balb/c mice Modulación mediada por licopeno de la clastogenicidad hepática inducida por 7,12 dimetilbenz (A antraceno en ratones macho BALB/C

    Directory of Open Access Journals (Sweden)

    A. Koul

    2010-04-01

    Full Text Available The present study was designed to evaluate the modulatory effects of lycopene against 7, 12 Dimethylbenz (a anthracene induced clastogenicity and oxidative stress in male Balb/c mice. The animals were divided into four groups; group I served as control (vehicle treated. Animals of group III and IV were administered lycopene orally at a dose of 4 mg/kg body weight for 10 weeks. Groups II and IV were administered DMBA, i.p., at a dose level of 40mg/kg body weight, 48hrs before the sacrifice of animals. Exposure to DMBA clearly induced hepatic cell injury as was evident by an increase in micronucleated cell score, lactate dehydrogenase and alkaline phosphatase activities, and Lipid Peroxidation levels. When the lycopene pre-treated animals were challenged with DMBA, a decrease in micronucleated cell score was observed, which was in corroboration with the observed decrease in LDH and ALP activities and LPO levels. DMBA treatment caused an increase in the oxidative stress with consequent alterations in enzymatic antioxidant defense system. Lycopene pre-treatment boosted the antioxidant defense in group IV. Thus, the antioxidant role of lycopene could be plausible in the protective action conferred by lycopene, enabling it to be used an effective natural free radical scavenger.El presente estudio se diseñó para evaluar los efectos moduladores del licopeno frente a la clastogenicidad y el estrés oxidativo inducidos por 7,12 dimetilbenz(A antraceno en los ratones macho Balb/c. Se dividió a los animales en cuatro grupos; el grupo I sirvió de control (tratado con vehículo. A los animales de los grupos III y IV se les administró licopeno por vía oral a una dosis de 4 mg/kg de peso corporal durante 10 semanas. Los grupos II y IV recibieron DMBA, i.p., a una dosis de 40 mg/kg de peso corporal, 48 horas antes de ser sacrificados. La exposición a DMBA indujo claramente una lesión de los hepatocitos como se hizo patente por el aumento de la puntuaci

  8. Computing along the axon

    Institute of Scientific and Technical Information of China (English)

    Chen Haiming; Tseren-Onolt Ishdorj; Gheorghe Pǎun

    2007-01-01

    A special form of spiking neural P systems, called axon P systems, corresponding to the activity of Ranvier nodes of neuron axon, is considered and a class of SN-like P systems where the computation is done along the axon is introduced and their language generative power is investigated.

  9. Cholestasis induced by total parenteral nutrition: effects of the addition of Taurine (Tauramin® on hepatic function parameters; possible synergistic action of structured lipids (SMOFlipid® Colestasis inducida por nutrición parenteral total: efecto de la adición de Taurina (Tauramin® sobre los parámetros de función hepática; posible acción sinérgica de lípidos estructurados (SMOFlipid®

    Directory of Open Access Journals (Sweden)

    J. González-Contreras

    2012-12-01

    Full Text Available Objective: Assess the hepatoprotective effect of Taurine (Tau in cases of hepatic cholestasis induced by Total Parenteral Nutrition (TPN. Methods: We describe a retrospective series of 54 patients who received TPN, in which cholestasis was detected at an (Intermediate point that separates the duration of TPN into 2 Phases. From this moment -Phase 2- on, and according to clinical criteria, some patients (Group A, n = 27 received amino acids with Tau (22.41 ± 3.57 mg/kg/day(Tauramin®, while the rest (Group B, n = 27 received the standard solution without Tau. The mean TPN durations were 39.2 ± 17.1 and 36.4 ± 18.1 days respectively, with the Intermediate points on days 19.56 ± 10.51 and 17.89 ± 11.14. They all received diets that were homogeneous in terms of kcal and macronutrients. In Phase 2, 21 patients from Group A received structured lipids (SMOFlipid®; while 20 from Group B received soy MCT/LCT [ Medium Chain Triglycerides/Long Chain Triglycerides ] (physical or structured mixture. In a retrospective study, differences could not be avoided. The analytical parameters from three periods (Initial, Intermediate, and Final were obtained from Nutridata® and Servolab®. We compared interperiod values using the Wilcoxon test SPSS® (p Objetivo: Evaluar el papel hepatoprotector de Taurina (Tau en situación de colestasis hepática inducida por Nutrición Parenteral Total (NPT. Métodos: Se describe una serie retrospectiva de 54 pacientes, que recibieron NPT, detectándose colestasis en un momento (Intermedio que separa en 2 Fases la duración de la NPT. A partir de este momento - Fase 2- y según criterios clínicos, unos -grupo A, n = 27- recibieron aminoácidos con Tau -22,41 ± 3,57 mg/kg/día (Tauramin®, mientras otros -grupo B, n = 27- recibieron solución estándar sin Tau. La duración media de NPT fue de 39,2 ± 17,1 y 36,4 ± 18,1 días respectivamente; con el punto Intermedio en día 19,56 ± 10,51 y 17,89 ± 11,14. Todos

  10. Axonal GABAA receptors.

    Science.gov (United States)

    Trigo, Federico F; Marty, Alain; Stell, Brandon M

    2008-09-01

    Type A GABA receptors (GABA(A)Rs) are well established as the main inhibitory receptors in the mature mammalian forebrain. In recent years, evidence has accumulated showing that GABA(A)Rs are prevalent not only in the somatodendritic compartment of CNS neurons, but also in their axonal compartment. Evidence for axonal GABA(A)Rs includes new immunohistochemical and immunogold data: direct recording from single axonal terminals; and effects of local applications of GABA(A)R modulators on action potential generation, on axonal calcium signalling, and on neurotransmitter release. Strikingly, whereas presynaptic GABA(A)Rs have long been considered inhibitory, the new studies in the mammalian brain mostly indicate an excitatory action. Depending on the neuron that is under study, axonal GABA(A)Rs can be activated by ambient GABA, by GABA spillover, or by an autocrine action, to increase either action potential firing and/or transmitter release. In certain neurons, the excitatory effects of axonal GABA(A)Rs persist into adulthood. Altogether, axonal GABA(A)Rs appear as potent neuronal modulators of the mammalian CNS.

  11. Axons take a dive

    Science.gov (United States)

    Tong, Cheuk Ka; Cebrián-Silla, Arantxa; Paredes, Mercedes F; Huang, Eric J; García-Verdugo, Jose Manuel; Alvarez-Buylla, Arturo

    2015-01-01

    In the walls of the lateral ventricles of the adult mammalian brain, neural stem cells (NSCs) and ependymal (E1) cells share the apical surface of the ventricular–subventricular zone (V–SVZ). In a recent article, we show that supraependymal serotonergic (5HT) axons originating from the raphe nuclei in mice form an extensive plexus on the walls of the lateral ventricles where they contact E1 cells and NSCs. Here we further characterize the contacts between 5HT supraependymal axons and E1 cells in mice, and show that suprependymal axons tightly associated to E1 cells are also present in the walls of the human lateral ventricles. These observations raise interesting questions about the function of supraependymal axons in the regulation of E1 cells. PMID:26413556

  12. Axonal bleb recording

    Institute of Scientific and Technical Information of China (English)

    Wenqin Hu; Yousheng Shu

    2012-01-01

    Patch-clamp recording requires direct accessibility of the cell membrane to patch pipettes and allows the investigation of ion channel properties and functions in specific cellular compartments.The cell body and relatively thick dendrites are the most accessible compartments of a neuron,due to their large diameters and therefore great membrane surface areas.However,axons are normally inaccessible to patch pipettes because of their thin structure; thus studies of axon physiology have long been hampered by the lack of axon recording methods.Recently,a new method of patchclamp recording has been developed,enabling direct and tight-seal recording from cortical axons.These recordings are performed at the enlarged structure (axonal bleb) formed at the cut end of an axon after slicing procedures.This method has facilitated studies of the mechanisms underlying the generation and propagation of the main output signal,the action potential,and led to the finding that cortical neurons communicate not only in action potential-mediated digital mode but also in membrane potential-dependent analog mode.

  13. Efeito da perda ponderal induzida pela cirurgia bariátrica sobre a prevalência de síndrome metabólica Efecto de la pérdida ponderal inducida por la cirugía bariátrica sobre la prevalencia de síndrome metabólico Effects of weight loss induced by bariatric surgery on the prevalence of metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Francisco das Chagas Monteiro Júnior

    2009-06-01

    Full Text Available FUNDAMENTO: A síndrome metabólica (SM está frequentemente ligada ao excesso de peso e melhora com a perda ponderal, sendo esperado que essa melhora seja proporcional à intensidade dessa perda. OBJETIVO: Avaliar o impacto da perda ponderal induzida pela cirurgia bariátrica (CB sobre a prevalência da SM, em médio prazo. MÉTODOS: Foram analisados 35 pacientes submetidos à cirurgia de by-pass gastrojejunal em Y de Roux, no período de outubro de 2001 a outubro de 2005, em nosso HU, sendo 88,5% do sexo feminino, com uma média de idade de 37,8±11,1 anos e um IMC médio de 45,0±6,2 kg/m². Na primeira etapa da pesquisa, foram obtidos dados demográficos e clínico-antropométricos antes da realização da CB, incluindo os critérios para o diagnóstico da SM, de acordo com as diretrizes do NCEP dos Estados Unidos. Na segunda etapa, os pacientes operados foram reavaliados ambulatorialmente quanto à prevalência da SM. RESULTADOS:Antes da cirurgia, a SM foi diagnosticada em 27 pacientes (77,1%. Em reavaliação 34,4±15 meses após a cirurgia, observou-se uma queda do IMC médio para 28,3±5,0 kg/m² e a SM foi detectada em apenas dois pacientes (5,7% (pFUNDAMENTO: El síndrome metabólico (SM frecuentemente está vinculado al exceso de peso y mejora con la pérdida ponderal, esperándose que esta mejora sea proporcional a la intensidad de esa pérdida. OBJETIVO: Evaluar el impacto de la pérdida ponderal inducida por la cirugía bariátrica (CB sobre la prevalencia de la SM, a medio plazo. MÉTODOS: Se estudiaron 35 pacientes sometidos a cirugía de bypass gastroyeyunal en Y de Roux, en el período de octubre de 2001 a octubre de 2005, en nuestro HU, siendo el 88,5% del sexo femenino, con un promedio de edades de 37,8±11,1 años y un IMC promedio de 45,0±6,2 Kg/m². En la primera etapa de la investigación, se obtuvieron datos demográficos y clínico antropométricos antes de la realización de la CB, incluyendo los criterios para el

  14. EFECTO PREVENTIVO DE LA Tabebuia serratifolia (Palo de Arco) EN UN MODELO MURINO DE COLITIS AGUDA INDUCIDA CON ÁCIDO ACÉTICO EN RATONES BALB-C MACHOS

    OpenAIRE

    Juan Nivin Huerta; Pamela Carbajal Urteaga; Lidia Aceituno Llana; Melissa Moras Rosado

    2013-01-01

    Objetivo: Determinar el efecto preventivo de la Tabebuia serratifolia en la colitis aguda inducida por ácido acético en ratones Balb/c. Métodos: Diseño: estudio experimental incompleto. Lugar: Instituto de Patología de la Universidad Nacional de San Marcos (Lima, Perú). Participantes: Ratones machos de la cepa balb/c. Intervenciones: Se administró extracto hidroalcohólico de Tabebuia serratifolia vía orogástrica por 4 días a 48 ratones distribuidos aleatoriamente en 6 grupos. La inducción se ...

  15. Glia to axon RNA transfer.

    Science.gov (United States)

    Sotelo, José Roberto; Canclini, Lucía; Kun, Alejandra; Sotelo-Silveira, José Roberto; Calliari, Aldo; Cal, Karina; Bresque, Mariana; Dipaolo, Andrés; Farias, Joaquina; Mercer, John A

    2014-03-01

    The existence of RNA in axons has been a matter of dispute for decades. Evidence for RNA and ribosomes has now accumulated to a point at which it is difficult to question, much of the disputes turned to the origin of these axonal RNAs. In this review, we focus on studies addressing the origin of axonal RNAs and ribosomes. The neuronal soma as the source of most axonal RNAs has been demonstrated and is indisputable. However, the surrounding glial cells may be a supplemental source of axonal RNAs, a matter scarcely investigated in the literature. Here, we review the few papers that have demonstrated that glial-to-axon RNA transfer is not only feasible, but likely. We describe this process in both invertebrate axons and vertebrate axons. Schwann cell to axon ribosomes transfer was conclusively demonstrated (Court et al. [2008]: J. Neurosci 28:11024-11029; Court et al. [2011]: Glia 59:1529-1539). However, mRNA transfer still remains to be demonstrated in a conclusive way. The intercellular transport of mRNA has interesting implications, particularly with respect to the integration of glial and axonal function. This evolving field is likely to impact our understanding of the cell biology of the axon in both normal and pathological conditions. Most importantly, if the synthesis of proteins in the axon can be controlled by interacting glia, the possibilities for clinical interventions in injury and neurodegeneration are greatly increased.

  16. Efecto hipolipidémico del extracto acuoso de las hojas de Artocarpus altilis "árbol del pan" en Rattus norvegicus con hiperlipidemia inducida

    Directory of Open Access Journals (Sweden)

    Julio Campos Florián

    2013-01-01

    Full Text Available La presente investigación tuvo como objetivo demostrar la actividad hipolipidémica del extracto acuoso de las hojas del árbol del pan, Artocarpus altilis, en un modelo de hiperlipidemia aguda inducida con tritón X-305, utilizando como especímenes Rattus norvegicus machos, peso promedio 204,5 g, a los que se les administró por vía oral 0,05 g/100 g y 0,2 g/100 g del extracto acuoso de A. altilis; se incluyó un grupo control negativo que recibió solución salina fisiológica y un grupo control positivo hiperlipidémico. Luego de 24 horas de administrar los tratamientos, se realizaron las mediciones en suero de las concentraciones de colesterol y triglicéridos. Encontramos reducciones significativas (p < 0,01 tanto de las cifras de colesterol, como de triglicéridos en relación a las concentraciones obtenidas en el grupo control positivo. También encontramos diferencia significativa (p < 0,01 entre las concentraciones de triglicéridos de los animales tratados con las dos dosis del extracto acuoso de A. altilis. Concluimos que el extracto acuoso de las hojas de A. altilis presenta efecto hipolipidémico a las dosis ensayadas para el modelo de hiperlipidemia inducida con tritón X-305.

  17. Theorical and experimental study of the induced forces by the mixed, divergent, convergent and straight labyrinth of seal systems on the steam turbines, gas turbines and compressor rotors; Estudio teorico-experimental de las fuerzas inducidas por los sistemas de sellos de laberinto rectos, convergentes, divergentes y mixtos sobre los rotores de turbinas de vapor, turbinas de gas y compresores

    Energy Technology Data Exchange (ETDEWEB)

    Salazar San Andres, Octavio Ramon

    1991-12-31

    demuestran que el modelo es capaz de dar una vision cualitativa y cuantitativa de las fuerzas y los coeficientes de rigidez y amortiguamiento de los sellos de laberinto con las geometrias antes mencionadas, tanto para el rotor estatico como en operacion. Por otra parte se recomienda llevar a cabo mas experimentacion con equipo instalado en plantas termoelectricas y en especial en turbinas de vapor con capacidades iguales o superiores a los 300 MW, donde las altas presiones y los sellos localizados en la parte superior de los alabes, vuelven mas susceptibles a las maquinas para autoinducir vibraciones subsincronas.

  18. Alteraciones histológicas en riñones de ratas, inducidas por dosis bajas del veneno de la serpiente Bothrops asper. - Histological injuries in rat’s kidneys induced to low dose of snake’s poison Bothrops asper.

    Directory of Open Access Journals (Sweden)

    Reyes, Adriana

    2009-09-01

    Full Text Available ResumenEl objetivo del trabajo fue demostrar que dosis bajas del veneno deBothrops asper pueden causar patologías renales que se acentúancon el tiempo de exposición al veneno, especialmente a nivelglomérular. Se emplearon cinco grupos de ratas de cinco individuoscada uno, los cuales fueron inoculados con una dosis de veneno de2.1µg/g de peso (por vía intraperitoneal, con adición de un grupocontrol, al cual se le inyectó solución salina. A los animales se lespracticó la eutanasia secuencialmente (1, 48, 96, 144 y 288 horas.En cada tiempo se extrajeron los riñones del grupo seleccionado, paraprocesarlos con técnicas de coloración (HE – PAS. Con el diagnósticohistopatológico se evidenció en la primera hora gloméruloscongestionados con tumefacción, después de 48 horas se presentóuna glomérulonefritis, seguida de un colapso glomerular a las 96horas. Las patologías se evidenciaron mas en los últimos períodos deexperimentación; a las 144 horas se observó glomérulonefritismembranosa y proliferativa endocapilar culminando con la desaparición de la cápsula de Bowman y la estructura total del glomérulo a las 288 horas. Se concluye que cantidades bajas del veneno pueden causar patologías renales progresivas con el paso del tiempo.SummaryAim of this work was to demonstrate that low doses of Bothropsasper venom can cause pathologies that progress over time on therenal tissue, at the glomerular level especially. Five groups of ratsconsisting of five individuals were used and a single dose of poison2.1µg/g in weight was injected. Control group was injected withsaline solution. Euthanasia sequentially was practiced (1, 48, 96, 144and 288 hours. In each time was extracted the kidneys of groupselection, to procession with color’s techniques (HE – PAS.Histopathological diagnostic evidenced congested glomeruli withswelling in the first hour, after 48 hours a glomerulonephritis waspresented, followed by a collapsed glomerular at

  19. Evaluación a través de tomografía computarizada del efecto de una infusión endovenosa de ketamina en el desarrollo de atelectasia inducida por anestesia general en perros Evaluation of an endovenous ketamine infusion through computed tomography on the development of pulmonary atelectasis due to general anesthesia in dogs

    Directory of Open Access Journals (Sweden)

    CA Henríquez

    2011-01-01

    Full Text Available El objetivo del estudio fue evaluar, a través de tomografía computarizada, el efecto de una infusión endovenosa de ketamina sobre la atelectasia pulmonar en perros sometidos a anestesia inhalatoria. Para esto se utilizaron 12 perros separados en dos grupos (A y B de 6 perros cada uno. Ambos fueron sometidos al mismo protocolo anestésico que consistió en premedicación con xilacina, inducción con propofol y mantención con anestesia inhalatoria por un periodo de dos horas. Al grupo B se le administró además una infusión de ketamina. Se realizaron cortes tomográficos 1 cm craneal al diafragma, en los minutos 0, 60 y 120 posteriores a la inducción, con el fin de monitorear la evolución en el caso de presentarse atelectasia. La totalidad del estudio fue realizado en las dependencias del Hospital Clínico Veterinario de la Universidad Austral de Chile. Se determinó la presencia de atelectasia en diferentes grados en el 58% de los perros, observándose en la totalidad de los animales en sólo uno de los pulmones. Además se presentó en 5 perros en el grupo sin infusión de ketamina y sólo 2 en el grupo con infusión. Asimismo, las áreas atelectásicas variaron entre 0,13 y 8,03 cm² en el grupo A y 0,07 y 2,10 cm² en el grupo B. La infusión de ketamina no influyó en la presentación de atelectasia pulmonar. Con respecto a la evolución de la atelectasia a través del tiempo, se apreciaron leves cambios en ambos grupos, los cuales no fueron estadísticamente significativos (P > 0,05.The aim of this study was to assess through computed tomography the presence of pulmonary atelectasis in dogs under inhalatory anesthesia and evaluate the effect of an endovenous ketamine infusion upon it. For this purpose 12 dogs separated in two groups (A and B of 6 dogs each were used. Both groups were subjected to the same anesthetic protocol. The protocol consisted in premedication with xilacine IM, induction with propofol IV and maintenance with

  20. Efeitos da fadiga muscular induzida por exercícios no tempo de reação muscular dos fibulares em indivíduos sadios Efectos de la fatiga muscular inducida por ejercicios sobre el tiempo de reacción muscular peronea en individuos sanos Effects of the exercise-induced muscular fatigue on the time of muscular reaction of the fibularis in healthy individuals

    Directory of Open Access Journals (Sweden)

    Bruno Araújo Rego Santos Silva

    2006-04-01

    Full Text Available A fadiga muscular (FM é um fenômeno comum nas atividades esportivas e diárias, resultando numa piora da performance motora. Ela é considerada um dos fatores causadores de lesões músculo-esqueléticas. A entorse de tornozelo é um exemplo: a FM afetaria tanto o sistema aferente quanto o eferente. Vários estudos têm analisado a influência da FM no controle neuromuscular (CNM; entretanto, existe pouca pesquisa sobre essa influência na velocidade de reação dos músculos. O objetivo deste estudo foi verificar os efeitos da FM no tempo de reação muscular (TRM dos músculos fibulares, que são os primeiros a responder a um estresse em inversão do tornozelo. Foram estudados 14 indivíduos saudáveis masculinos (idade: 20-35 anos, que tiveram seus TRM avaliados por meio de eletromiografia (EMG de superfície. O início da atividade muscular foi definido como a média de repouso + 3x o desvio-padrão (DP. O TRM dos fibulares foi mensurado após uma inversão súbita de 20º realizada numa plataforma. A inversão súbita foi realizada antes e depois da fadiga muscular, que foi induzida por exercícios localizados dos fibulares até a exaustão. Os resultados mostraram que houve um aumento significativo do tempo de reação muscular após a fadiga (p La fatiga muscular (FM es un fenómeno común en las actividades diarias, produciendo un empeoramiento de la actuación. Se la considera una de las causas de factores lesionantes musculares de esqueleto. El esguince del tobillo es un ejemplo: La FM afectaría tanto el sistema aferente cuanto el eferente. Varios estudios han estado analizando la influencia de FM en el comando neuromuscular (CNM, sin embargo, la existen pocas investigaciones sobre la influencia en la velocidad de reacción de los músculos. El objetivo de ese estudio era verificar los efectos de FM en el tiempo de reacción muscular (TRM de los músculos peroneos, que son los primeros en responder a una tensión en la inversi

  1. Evaluación del estado ácido-base en terneros con acidosis ruminal inducida experimentalmente: aplicación de dos modelos de diagnóstico

    OpenAIRE

    Baquero Parrado, Johann Ricardo

    2015-01-01

    Introducción: Durante la lactación del ternero puede alterarse el reflejo de cierre de la gotera esofágica conduciendo a acidosis ruminal por D-lactato con implicaciones fisiológicas importantes como alteraciones en el crecimiento, baja ganancia de peso y pérdidas económicas importantes. Objetivos: Evaluar el estado ácido-base en terneros con acidosis ruminal inducida experimentalmente. Hipótesis: La acidosis metabólica de origen ruminal, en terneros neonatos, puede ser diagnosticada ig...

  2. Citotoxicidad inducida por veneno de serpientes peruanas sobre fibroblastos de ratón

    OpenAIRE

    Goñi, María; Vaisberg,Abraham; Zavaleta, Alfonso

    2016-01-01

    Los venenos de serpientes contienen una amplia gama de toxinas que desencadenan múltiples transtornos fisiopatológicos (edema, hemorragia, destrucción muscular, etc.), y alteran la fIsiología de órganos y sistemas (cardiovascular. neuromuscular, hemostático y otros) Los venenos de serpientes contienen una amplia gama de toxinas que desencadenan múltiples transtornos fisiopatológicos (edema, hemorragia, destrucción muscular, etc.), y alteran la fIsiología de órganos y sistemas (cardiovascul...

  3. Muerte celular inducida por condiciones ambientales adversas en Calibrachoa parviflora (Petunia

    Directory of Open Access Journals (Sweden)

    Daniela Montes Berrueta

    2012-03-01

    Full Text Available Se ha descrito que condiciones ambientales extremas tales como altas temperaturas, luz ultravioleta y el efecto invernadero, alteran la tasa de crecimiento de las plantas. En este trabajo se investigó el efecto agudo de dos condiciones ambientales extremas tales como la limitación de nutrientes y la acidificación del suelo con ácido sulfúrico, un compuesto comúnmente depositado en los suelos como consecuencia de la llamada lluvia ácida, sobre la tasa de muerte y proliferación celular en petunias (Calibrachoa parviflora. Para tales efectos, grupos de petunias fueron sometidas a tres condiciones diferentes: grupo A o control, mantenida en condiciones óptimas y de suministro de nutrientes, grupo B en ausencia de nutrientes y de luz natural, y grupo C expuestas a agua acidificada con ácido sulfúrico. En un seguimiento hasta 72 horas, se analizaron muestras de pétalos, hojas y tallos de cada una de las plantas y, posterior a la extracción de los núcleos, estos fueron teñidos con ioduro de propidio, un agente intercalante del ADN, y analizados mediante citometría de flujo y microscopía de fluorescencia. Los resultados muestran que ambas condiciones extremas generan un desbalance en el proceso de muerte/sobrevida de las petunias, pero a diferencia de las plantas del grupo B, las plantas del grupo C no incrementaron la tasa de proliferación celular. Estos resultados sugieren que las plantas que crecen en suelos ácidos pierden la capacidad compensatoria ante la señal de estrés que se genera a consecuencia de la exposición aguda a concentraciones tóxicas de ácido sulfúrico. Cell death induced by adverse environmental conditions in Calibrachoa parviflora (petunia Abstract It has been previously reported that extreme environmental conditions such as high temperatures, ultraviolet light and the greenhouse effect, alter the rate of growth in plants. In this study we investigated the acute effect of two extreme environmental conditions: nutrient deprivation and soil acidification with sulfuric acid, a compound commonly deposited in the soil, as a result of acid rain, on the rate of death and cell proliferation in petunias (Calibrachoa parviflora. For this purpose, a group of petunias was subjected to three different conditions: group A or control, kept in optimum conditions and nutrient supply, group B in the absence of nutrients and natural light and group C, exposed to water acidified with sulfuric acid. In continuous observations for up to 72 hours, samples from petals, leaves and stems of each plant were analyzed and after nuclei extraction; these were treated with propidium iodide, a DNA intercalator compound, and analyzed by flow cytometry and fluorescence microscopy. The results show that both extreme conditions generate an imbalance in the process of death/survival of petunias, but unlike plants from group B, plants in group C, did not increase their rate of cell proliferation. These results suggest that plants growing in acid soils lose their ability to compensate the stress signal generated as a result of acute exposure to toxic concentrations of sulfuric acid.

  4. Polymerization of sodium methacrylate induced by irradiation; Polimerizacion del metacrilato de sodio inducida por la irradiacion

    Energy Technology Data Exchange (ETDEWEB)

    Galvan S, A. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencias Basicas, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    This work has two objectives, first: it is pretended to localize the lines of carbon links in its IR spectra, and second: following the polymerization of sodium methacrylate according to that it is irradiated with gamma rays. (Author)

  5. Prevalencia y severidad de la disfunción intestinal inducida por opioides

    Directory of Open Access Journals (Sweden)

    Rafael Gálvez

    2014-01-01

    Conclusiones: En pacientes con tratamiento opioide se constata una elevada frecuencia de trastornos gastrointestinales posiblemente relacionados con la DIO, lo que subraya la necesidad de nuevas estrategias para su tratamiento.

  6. Daño oxidativo y muerte neuronal en un modelo de hipoglucemia inducida por insulina /

    OpenAIRE

    Haces del Blanco, María Luisa sustentante.

    2009-01-01

     tesis que para obtener el grado de Doctor en Ciencias Biomédicas, presenta María Luisa Haces del Blanco ; asesor Lourdes Massieu Trigo. 121 páginas : ilustraciones. Doctorado en Ciencias Biomédicas UNAM, Instituto de Fisiología Celular, 2009

  7. Chromosomal aberrations induced by alpha particles; Aberraciones cromosomicas inducidas por particulas {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero C, C.; Brena V, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: cgc@nuclear.inin.mx

    2005-07-01

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  8. El aceite de pescado atenua las crisis convulsivas inducidas por hipertermia en ratas neonatas

    OpenAIRE

    Leopoldo E. Flores M.; Miguel A. Guevara; Alfredo Feria-Velasco; Luís Cerdán S.; Marisela Hernández-González

    2008-01-01

    Un alto porcentaje (50-60%) del cerebro en los mamíferos son principalmente grasas o lípidos, de éstos, el 35% son ácidos grasos esenciales, en particular los llamados omegas (O), como el Acido Docosahexanoico (DHA) y el Eicosapentanoico (EPA) llamados omega 3 (O-3). Diversos estudios han mostrado beneficios en la salud con la implementación de los O-3 como agentes terapéuticos en alteraciones cardiovasculares, renales, dérmicas, metabólicas, neurodegenerativas e inmunológicas. Evidencias ...

  9. Respuesta inmune mucosal inducida por proteoliposoma y cocleato derivados de N. meningitidis serogrupo B

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    Judith del Campo

    2009-08-01

    Full Text Available Mucosal vaccination offers attractive advantages to conventional systemic vaccination. Most pathogens enter or establish infection at mucosal surfaces. This represents an enormous challenge for vaccine development. Nevertheless, the availability of safe and effective adjuvants that function mucosally is the major limitation. Therefore, we investigated the impact of mucosal immunization with the Neisseria meningitidis B proteoliposome (AFPL1, Adjuvant Finlay Proteoliposome 1 and its-derived cochleate (Co, AFCo1. They contain multiple PAMPs as immunopotentiators and have delivery system ability as well as Th1 polarization activity. Groups of female mice were immunized by nasal, oral, intravaginal, or intramuscular routes with three doses with AFPL1/AFCo1 alone or containing ovalbumin or glycoprotein (g D2 from Herpes Simplex Virus type 2 (HSV-2. High levels of specific IgG antibodies were detected in sera of mice vaccinated with either route. However, specific IgA antibodies were produced in saliva and vaginal wash only following mucosal delivering. The polarization to a Th1 pattern was confirmed by testing the induction of IgG2a/IgG2c antibody, positive delayed-type hypersensitivity reactions, and gIFN production. Additionally, AFCo1gD2 showed practically no vaginal HSV-2 replication and 100% protection against lethal vaginal HSV-2 challenge. In conclusion, the results support the use of AFCo1 as potent Th1 adjuvant for mucosal vaccines, particularly for nasal route.

  10. Estudio morfométrico de las malformaciones craneofaciales experimentales inducidas por ácido retinoico

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    T. González

    2003-10-01

    Full Text Available Objetivo: El ácido retinoico es un metabolito activo de la vitamina A que administrado en grandes cantidades tiene efecto teratógeno sobre la embriogénesis de los mamíferos. Hemos investigado los efectos de la exposición temprana de embriones de rata sobre las estructuras craneofaciales. Diseño: Cuarenta y cinco ratas Sprague-Dawley gestantes fueron tratadas con 125 mg/kg de ácido all-trans-retinoico el día 10 de gestación. Las 20 ratas controles fueron tratadas con aceite. Los fetos de ambos grupos se extrajeron el día antes de llegar a término y fueron sometidos a un estudio morfológico y otro estudio morfométrico, analizando las malformaciones craneofaciales. Resultados: Ninguno de los fetos controles presentó malformaciones. El 100% de los embriones tratados con retinoico presentaron defectos craneofaciales, incluyendo fisuras faciales, exoftalmos, malformaciones e inserción baja de los pabellones auriculares, apéndices faciales y anomalías nasales. El análisis morfométrico reveló un incremento de la distancia entre los poros nasales (pObjective: Retinoic acid is an active metabolite of Vitamin A that is teratogenic when present in excess during mammalian embriogenesis. We have investigated the effects of early exposure of rat embryos to retinoic acid on craniofacial structures. Design: Treatment of 45 pregnant Sprague-Dawley rats with 125mg./Kg all-trans-retinoic acid on pregnancy day 10 was performed. Twenty controls were treated only with oil. The fetuses were recovered the day before term, and both morphologic and morphometric analyses of the craniofacial structures were performed. Results: None of the control fetuses had malformations. Craniofacial defects were observed in 100% of the retinoic embryos including facial clefts, proptosis, abnormalities and inferior placement of the pinnae, skin tags, and nasal anomalies. Morphometric analyses revealed an increased distance between nasal pores (p<0,01 and between both eyes (p<0,05 in retinoic embryos. A reduced distance of the maxilla (p<0,01 and the mandible (p<0,01 were also noted. Conclusions: Morphologic and morphometric studies confirm the hypothesis that retinoic acid disturbs normal craniofacial development when administered during a critical period. Hindrance of migration of the cranial neural crest cells may be a main reason to explain these events.

  11. HIPONATREMIA INDUCIDA POR PERDIDA URINARIA DE SODIO EN EL ANCIANO BAJO DIETA HIPOSODICA

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    Luis S. Algranati L

    2006-04-01

    Full Text Available ABSTRACTHyponatremia is an electrolyte disorder which consist of a relative increase in body free water content respect to sodium one. Free water retention or sodium loss are its possible mechanisms, being the former more frequent than the latter. However, since urinary sodium loss is increased in healthy elderly, sodium depletion can be a frequent etiology of hyponatremia in this people when they have been on a low sodium diet for a long period.In this report a case of hyponatremia that solved with sodium restitution instead of water restriction is presented, and the name of senile sodium leakage hyponatremia is proposed for this entity. It is also analyzed the low reliability that fractional excretion of urea seems to have in the evaluation of this syndrome. RESUMENLa hiponatremia es un desorden electrolítico que consiste en un aumento relativo a nivel corporal del contenido acuoso respecto del salino.La retención de agua libre o la pérdida de sodio son sus mecanismos causales principales, siendo el primero de ellos el más frecuente. Sin embargo, dado que los ancianos normales poseen un aumento en la excreción urinaria de sodio respecto de los jóvenes, pueden desarrollar hiponatremia secundaria a deplección salina cuando han estado en forma prolongada bajo una dieta hiposódica.En este reporte presentamos un caso de hiponatremia que fue resuelto mediante la restitución de sodio y no mediante la restricción hídrica. Analizamos también la baja confiabilidad de la excreción fraccional de urea en la interpretación de la etiología de la hiponatremia en los ancianos.

  12. Enfermedades pleurales benignas inducidas por asbesto Benign pleural diseases induced by asbestos

    Directory of Open Access Journals (Sweden)

    J. Boldú

    2005-01-01

    Full Text Available La exposición al asbesto es una causa importante de patología pleural y se puede producir con intensidades moderadas o ligeras dada la capacidad del asbesto de concentrarse en la pleura. Ello motiva junto a la prolongada latencia existente entre la exposición y la enfermedad, que sigamos viendo durante muchos años manifestaciones clínicas pleurales de exposición previa, a pesar del uso del asbesto cada vez más limitado en las últimas décadas. Dicha exposición puede presentarse con distintas manifestaciones tanto malignas como el mesotelioma como benignas, siendo las principales de éstas el derrame pleural benigno, las placas pleurales, la fibrosis pleural difusa y la atelectasia redonda.Exposure to asbestos is an important cause of pleural pathology and can be produced with light or moderate tendencies given the capacity of asbestos to concentrate in the pleura. Together with the prolonged latency existing between exposure and the disease, this means that for many years we will continue to see pleural clinical manifestations from past exposure, in spite of the increasingly limited use of asbestos in recent decades. This exposure can show itself in different manifestations, both malign, such as mesothelioma, and benign, principally benign pleural effusion, pleural plaques, diffuse pleural fibrosis and massive atelectasis.

  13. Estudio de la utilización de la alanina y otros aminoácidos por el tejido adiposo marrón interescapular de la rata

    OpenAIRE

    López Soriano, Francisco J.

    1987-01-01

    El tejido adiposo marrón (TAM) está considerado como el principal efector de la termogénesis no temblorosa inducida por el frío y de la termogénesis facultativa inducida por la dieta en la rata y otras especies de mamíferos.Debido a su importancia en estos procesos; al metabolismo del TAM ha sido muy estudiado, si bien los aspectos relacionados con el metabolismo de los aminoácidos han recibido muy poca atención. El objetivo del presente estudio ha sido determinar las características generale...

  14. Efecto del extracto del fruto de Physalis peruviana "tomatillo" en Mus musculus var. swis con hiperlipidemia inducida.

    Directory of Open Access Journals (Sweden)

    Julio Campos Florián

    2011-01-01

    Full Text Available El objetivo de la presente i nvestigación fue determinar la actividad hipolipidémica del fruto de Physalis peruviana “tomatillo” en un modelo de hiperlipidemia aguda inducida con tritón. Se utilizaron Mus musculus var. swis machos como animales de experimentación. Se trabajó con cuatro grupos de ratones, el grupo blanco recibió agua destilada por vía oral y solución salina fisiológica por vía intraperitoneal, el grupo control recibió agua destilada por vía oral y tritón por vía intraperitoneal, el grupo problema 1 recibió por vía oral 0.05g/100g del extracto de Physalis peruviana y tritón por vía intraperitoneal y el grupo problema 2 recibió por vía oral 0.2g/100g del extracto de Physalis peruviana y tritón por vía intraperitoneal. Luego de 24 horas de administrar los tratamientos se re alizaron las mediciones en suero de las concentraciones de colesterol y triglicéridos. Los niveles promedio de colesterol (mg/dL fueron: 58.87±11.54 (blanco, 121.71±15.00 (control, 58.08±9. 21 (problema 1 y 66.78±16.77 (problema 2. Los niveles promedio de triglicéridos (g/L fueron: 0.48±0.07 (blanco, 1.84±0.18 (control, 0.34±0.10 (problema 1 y 0.94±0.25 (problema 2. Se encontró reducciones significativas (p<0.000, tanto de las concentraciones de colesterol como de triglicéridos en relación a las o btenidas en el grupo tratado sólo con tritón.

  15. causada por Fusarium moniliforme

    Directory of Open Access Journals (Sweden)

    Mariano Mendoza Elos

    2006-01-01

    Full Text Available El objetivo de éste trabajo fue determinar la resistencia horizontal de 134 líneas S1 de maíz al hongo Fusarium moniliforme. La enfermedad fue inducida mediante inoculación en la etapa de floración masculina bajo condiciones de campo utilizando la técnica del palillo. Las líneas se evaluaron en México en 2002. La estimación de la enfermedad se hizo en dos ocasiones con una separación de 20 días. Las evaluaciones mostraron que las líneas Roque-801, 804, 1103 y 1405 fueron resistentes en la primera evaluación. Las tasas de incremento de la enfermedad variaron de 0,01 a 0,229 por unidad por día. Las líneas mostraron bajos niveles de enfermedad de 0 a 1 % en la primera evaluación. En la segunda evaluación, los niveles de enfermedad variaron de 49 a 100 %. En un programa de mejoramiento genético estas líneas pueden ser utilizadas para mejorar la resistencia horizontal del maíz a la pudrición del tallo causada por Fusarium moniliforme

  16. The genetics of axonal transport and axonal transport disorders.

    Directory of Open Access Journals (Sweden)

    Jason E Duncan

    2006-09-01

    Full Text Available Neurons are specialized cells with a complex architecture that includes elaborate dendritic branches and a long, narrow axon that extends from the cell body to the synaptic terminal. The organized transport of essential biological materials throughout the neuron is required to support its growth, function, and viability. In this review, we focus on insights that have emerged from the genetic analysis of long-distance axonal transport between the cell body and the synaptic terminal. We also discuss recent genetic evidence that supports the hypothesis that disruptions in axonal transport may cause or dramatically contribute to neurodegenerative diseases.

  17. Evaluación de Protección para la Reducción de Corrientes Inducidas en el Tanque del Transformador

    Directory of Open Access Journals (Sweden)

    Mario Salvador Esperanza González

    2011-01-01

    Full Text Available En este trabajo se evalúa la distribución de blindajes electromagnéticos contra corrientes inducidas en las paredes del tanque de transformadores eléctricos mediante el método del elemento finito utilizando el software femm 4.2. Se evalúan arreglos, a con laminaciones del shunt magnético paralelas a la pared del tanque y b blindaje electromagnético de aluminio. Se evalúan 5 acomodos diferentes de las protecciones, considerando una separación entre el tanque y el conductor que varía de 5.08 cm hasta 25.4 cm, se considera en el estudio una geometría de 3 conductores paralelos al tanque con una corriente de 5kA por fase y cada fase desfasada 120 grados entre sí, se utiliza acero al carbón para la pared del tanque y acero al silicio convencional para los shunts magnéticos. La posición óptima de las laminaciones de los shunts se determina a partir de la evaluación de pérdidas totales inducidas tanto en la pared del tanque como en los shunts magnéticos o en el blindaje electromagnético, según sea el caso. De acuerdo con los resultados del modelado se determina que puede obtenerse el mismo nivel de reducción de pérdidas con menor cantidad de material de protección encontrando una distribución óptima de las mismas.

  18. Flora bucal en perros de la raza Beagle con enfermedad periodontal inducida

    OpenAIRE

    Cabrera García, Alexei; Guerra Barroso Mabel; Soto Cantero Luis; Soca Pérez, Maylin; Rodríguez Sosa, Víctor Manuel; Dominguez López, Heberto Arides; Purón Guzmeli, Carlos Alberto; Macías Hernández, Ileana; Aliaga Aleaga, Yilenis; Acosta Berbes, Anais; Guerrero Contreras, Miladys; Gil Díaz, Felipe Alejandro

    2012-01-01

    ResumenLa enfermedad periodontal afecta a los perros durante toda su vida y se debe a la acumulación de placa dental bacteriana en las coronas dentales a lo largo de la encía, lo que conlleva a una reacción inflamatoria de la misma, conocida como gingivitis. Con el fin determinar la flora bucal en perros con enfermedad periodontal inducida se estudiaron 10 canes de la raza Beagle que previamente fueron sometidos a una intervención quirúrgica para inducir la enfermedad.SummaryPeriodontal disea...

  19. Transcellular degradation of axonal mitochondria.

    Science.gov (United States)

    Davis, Chung-ha O; Kim, Keun-Young; Bushong, Eric A; Mills, Elizabeth A; Boassa, Daniela; Shih, Tiffany; Kinebuchi, Mira; Phan, Sebastien; Zhou, Yi; Bihlmeyer, Nathan A; Nguyen, Judy V; Jin, Yunju; Ellisman, Mark H; Marsh-Armstrong, Nicholas

    2014-07-01

    It is generally accepted that healthy cells degrade their own mitochondria. Here, we report that retinal ganglion cell axons of WT mice shed mitochondria at the optic nerve head (ONH), and that these mitochondria are internalized and degraded by adjacent astrocytes. EM demonstrates that mitochondria are shed through formation of large protrusions that originate from otherwise healthy axons. A virally introduced tandem fluorophore protein reporter of acidified mitochondria reveals that acidified axonal mitochondria originating from the retinal ganglion cell are associated with lysosomes within columns of astrocytes in the ONH. According to this reporter, a greater proportion of retinal ganglion cell mitochondria are degraded at the ONH than in the ganglion cell soma. Consistently, analyses of degrading DNA reveal extensive mtDNA degradation within the optic nerve astrocytes, some of which comes from retinal ganglion cell axons. Together, these results demonstrate that surprisingly large proportions of retinal ganglion cell axonal mitochondria are normally degraded by the astrocytes of the ONH. This transcellular degradation of mitochondria, or transmitophagy, likely occurs elsewhere in the CNS, because structurally similar accumulations of degrading mitochondria are also found along neurites in superficial layers of the cerebral cortex. Thus, the general assumption that neurons or other cells necessarily degrade their own mitochondria should be reconsidered.

  20. Evaluación de la reproducción inducida de nicuro Pimelodus blochii (Telostei: Pimelodidae utilizando diferentes inductores hormonales

    Directory of Open Access Journals (Sweden)

    Juan Ramírez M.

    2013-08-01

    Full Text Available Objetivo. Evaluar el efecto de dos inductores hormonales en la reproducción inducida de nicuro Pimelodus blochii. Materiales y métodos. Para los procesos experimentales fueron utilizados adultos sexualmente maduros, sometidos a tres tratamientos aplicados vía intramuscular, en dosis única de 0.25 mL/kg Ovaprim® (OVAP (T1, 0.5 mL/kg de OVAP (T2 y 6.25 mg/kg de Extracto de Hipófisis de Carpa (EHC (T3, para este último tratamiento la inyección fue dividida en 20 y 80%, con un intervalo de 12 h entre aplicaciones. Previo a la extracción de los gametos, los animales fueron tranquilizados por inmersión en una solución de Metanosulfonato de Tricaina (90 mg/L. El desempeño reproductivo fue evaluado mediante el índice de ovulación (hembras ovuladas/hembras tratadas, fecundidad absoluta (Fa (ovocitos/hembra, fecundidad relativa (Fr en función del número de ovocitos desovados por gramo de peso. La fecundación se realizó en seco y seis horas post-fecundación (HPF se determinó la tasa de fertilidad. Resultados. La ovulación (ºh para el T1 fue a las 297.1±30.0, T2 294.6±32.9 y T3 247.3±13.1 ºh. En todos los tratamientos se obtuvieron hembras ovuladas, donde los mayores índices de ovulación fueron obtenidos con Ovaprim® (T1 y T2 con 36.4 y 50%, respectivamente. Las tasas de fecundación obtenidas fueron mayores a un 50%, para el tratamiento 1 y 2, con valores de 74.5 y 32.7%, respectivamente. Conclusiones. El uso de inductores hormonales puede ser efectivo para garantizar la reproducción inducida del nicuro, en dosis única de 0.25 y 0.5 mL/kg de Ovaprim®.

  1. Action-potential modulation during axonal conduction.

    Science.gov (United States)

    Sasaki, Takuya; Matsuki, Norio; Ikegaya, Yuji

    2011-02-04

    Once initiated near the soma, an action potential (AP) is thought to propagate autoregeneratively and distribute uniformly over axonal arbors. We challenge this classic view by showing that APs are subject to waveform modulation while they travel down axons. Using fluorescent patch-clamp pipettes, we recorded APs from axon branches of hippocampal CA3 pyramidal neurons ex vivo. The waveforms of axonal APs increased in width in response to the local application of glutamate and an adenosine A(1) receptor antagonist to the axon shafts, but not to other unrelated axon branches. Uncaging of calcium in periaxonal astrocytes caused AP broadening through ionotropic glutamate receptor activation. The broadened APs triggered larger calcium elevations in presynaptic boutons and facilitated synaptic transmission to postsynaptic neurons. This local AP modification may enable axonal computation through the geometry of axon wiring.

  2. Producción Fúngica de Proteasas Inducidas con Pelo de Cerdo Fungal Production of Proteases Induced with Pig Hair

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    Imir R Vázquez

    2008-01-01

    Full Text Available Se evaluaron las condiciones de producción de proteasas fúngicas inducidas con pelo de cerdo usando dos sistemas de cultivo, el proceso de cultivo en estado sólido y el cultivo líquido sumergido. El medio de cultivo fue Czapek-Dox en ambos casos. La cinética fue monitoreada cada 24 horas durante un periodo de incubación de 120 horas. La actividad proteolítica fue evaluada por hidrólisis de azocaseína y la producción de la biomasa fue estimada por el método gravimétrico. Rhizopus oryzae fue el microorganismo capaz de utilizar el pelo de cerdo como única fuente de carbono-nitrógeno, produciendo en cultivo sumergido los mayores títulos de actividad queratinasa. Se determinó el efecto que tiene el pH, el pretratamiento del sustrato y la adición de diferentes niveles de material queratinoso sobre el crecimiento fúngico y la actividad enzimática. Los resultados permitieron obtener títulos de actividad proteolítica de 975 U/L.The production of new proteases induced with pig hair was evaluated using two systems, submerged culture and solid state culture. Culture medium was Czapek-Dox for both systems. Enzyme production kinetic was monitored each 24 hours during 120 hours. Protelytic activity was evaluated with the azocaseín method and biomass production was determined by the gravimetric method. Rhizopus oryzae was the microorganism with the capacity of using the pig hair as the single carbon-nitrogen source, producing in submerged fermentation the highest enzymatic titers. The effect of pH, the substrate pretreatment and addition of different levels of substrate on proteolyitic activity and biomass production were determined. Results permitted to obtain titers of proteolytic activity of 975 U/L.

  3. Manifestaciones reumáticas de la infección por el virus de inmunodeficiencia humana (VIH

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    Gloria María Vásquez Duque

    2005-02-01

    Full Text Available Con la aparición del VIH/SIDA se ha puesto de manifiesto un espectro de manifestaciones clínicas reumáticas. El compromiso articular incluye las artralgias, la artritis por VIH, el síndrome de Reiter, la artritis psoriásica y la espondiloartropatía indiferenciada. También se ha documentado una miopatía inducida por el VIH en cuyo diagnóstico diferencial se deben tener en cuenta la miopatía inducida por zidovudina y la debida a toxoplasmosis, cuya presentación clínica es más parecida a la miopatía inducida por el VIH que a otras afecciones musculares. El síndrome de linfocitosis con infiltración difusa es una entidad parecida al síndrome de Sjögren, que es exclusiva de los pacientes VIH positivos, con algunas diferencias en la presentación clínica e inmunológica. Por último, es frecuente la presencia de fenómenos autoinmunes el más común de los cuales es la hipergamaglobulinemia policlonal. También se han descrito diferentes tipos de vasculitis como parte de esta enfermedad.

  4. Frecuencia espontánea e inducida de micronúcleos transplacentarios en ratones Balb/c

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    Daniel Francisco Arencibia Arrebola

    2011-01-01

    Full Text Available Introducción: El ensayo de micronúcleos transplacentario, ha sido desarrollado con el objetivo de evaluar el potencial genotóxico en la descendencia y demostrar la capacidad de un agente de causar daños cromosómicos durante el período prenatal. Éste realiza el registro de aberraciones cromosómicas, demostrando si una sustancia determinada puede ser clastogénica o aneugénica en el feto, a través de la exposición materna. Objetivo: Por lo cual en el presente trabajo se tuvo como objetivo determinar la frecuencia espontánea e inducida de micronúcleos transplacentarios en ratones de la línea Balb/c. Pretendiendo vincular de esta forma el efecto genotóxico y reproductivo de una droga a evaluar por esta metodología. Materiales y métodos: Se formaron 4 grupos experimentales, el primero un control negativo (simulacro, el segundo control solvente NaCl (0,9%, en el tercero se utilizo la ciclofosfamida en dosis de 50 mg/kg, y el cuarto se utilizó la bleomicina en dosis de 20 mg/kg. Todos los grupos se administraron por vía intraperitoneal los días 14, 15 y 16 de la gestación y 24 h después de la última inoculación se procedió al sacrificio de las gestantes por dislocación cervical. Obteniéndose las muestras de médula ósea materna e hígado fetal. Resultados: Se obtuvo como resultado los valores espontáneos e inducidos de los índices de citotoxicidad y de genotoxicidad, así como el total de micronúcleos divididos según niveles de daños.Discusión y conclusiones: Se observo mayor inducción de daño en células hepáticas fetales que en médula ósea materna. Además se demostró que la ciclofosfamida es capaz de inducir mayor citotoxicidad y genotoxicidad que la bleomicina tanto en células de la médula ósea materna como en células hepáticas fetales. Por tanto se demostró el poder clastogénico transplacentario de ambos mutágenos vinculando este ensayo de genotoxicidad a la reproducción. Además estos resultados se

  5. Trolox reduces the effect of ethanol on acetylcholine-induced contractions and oxidative stress in the isolated rabbit duodenum El Trolox reduce el efecto del etanol sobre las contracciones inducidas a la acetilcolina y el estrés oxidativo en duodeno aislado de conejo

    Directory of Open Access Journals (Sweden)

    Diego S. Fagundes

    2011-08-01

    Full Text Available Trolox is a hydrophilic analogue of vitamin E and a free radical scavenger. Ethanol diminishes the amplitude of spontaneous contractions and acetylcholine (ACh-induced contractions in rabbit duodenum. The aim of this work was to study the effect of Trolox on the alterations induced by ethanol on contractility and lipid peroxidation in the duodenum. The duodenal contractility studies in vitro were carried out in an organ bath and the levels of malondialdehyde and 4-hydroxyalkenals (MDA+4-HAD were measured by spectrophotometry. Trolox increased the reduction induced by ethanol on the amplitude of spontaneous contractions in longitudinal muscle but not in circular muscle. Trolox 4 mM decreased the effects of ethanol on ACh-induced contractions and on MDA+4-HDA concentrations. We conclude that Trolox might prevent oxidative stress induced by ethanol in the duodenum.El Trolox es un análogo hidrofílico de la vitamina E y un agente que secuestra radicales libres. El etanol disminuye la amplitud de las contracciones espontáneas y las contracciones inducidas a la acetilcolina en el duodeno de conejo. El objetivo de este trabajo era estudiar el efecto del Trolox en las alteraciones inducidas por el etanol sobre la contractilidad y la peroxidación lipídica en el duodeno. Los estudios de contractilidad duodenal in vitro se realizaron en un baño de órganos y los niveles de MDA+4-HDA se midieron por espectofotometría. El Trolox aumentó la reducción inducida por el etanol sobre la amplitud de las contracciones espontáneas en el músculo longitudinal pero no en el músculo circular de duodeno. El Trolox 4 mM redujo los efectos del etanol sobre las contracciones inducidas a la acetilcolina y sobre las concentraciones de MDA+4-HDA. Se concluye que el Trolox podría prevenir el estrés oxidativo inducido por el etanol en el duodeno.

  6. El género afecta las propiedades contráctiles del músculo sóleo en diabetes inducida experimentalmente en ratas

    Directory of Open Access Journals (Sweden)

    Adolfo Virgen Ortiz

    2015-06-01

    Full Text Available Ratas hembras y machos, de tres meses de edad, fueron separados en dos grupos: no diabéticas (ND, peso corporal, 274 ± 9 g; nivel de glucosa en la sangre, 4,94 ± 0,22 mmol/L; n = 16 y diabéticas (D; peso corporal, 207 ± 8 g; nivel de glucosa en sangre, 28,39 ± 0,94 mmol/L; n = 16. La diabetes fue inducida por una sola dosis de 60 mg/Kg de estreptozotocina administrada intraperitonealmente. Las ratas ND recibieron el mismo volumen de vehículo. Después de 4 semanas los animales fueron considerados diabéticos si su nivel de glucosa era ≥ 20 mmol/L. La masa y la contracción del músculo sóleo fueron mayores en machos ND que en las hembras ND. En las ratas macho D disminuyó su masa muscular en un 34% y la fuerza de contracción disminuyó en un 33%; mientras que en las hembras D disminuyeron 15% y 10% respectivamente.

  7. EFECTO PREVENTIVO DE LA Tabebuia serratifolia (Palo de Arco EN UN MODELO MURINO DE COLITIS AGUDA INDUCIDA CON ÁCIDO ACÉTICO EN RATONES BALB-C MACHOS

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    Juan Nivin Huerta

    2013-07-01

    Full Text Available Objetivo: Determinar el efecto preventivo de la Tabebuia serratifolia en la colitis aguda inducida por ácido acético en ratones Balb/c. Métodos: Diseño: estudio experimental incompleto. Lugar: Instituto de Patología de la Universidad Nacional de San Marcos (Lima, Perú. Participantes: Ratones machos de la cepa balb/c. Intervenciones: Se administró extracto hidroalcohólico de Tabebuia serratifolia vía orogástrica por 4 días a 48 ratones distribuidos aleatoriamente en 6 grupos. La inducción se realizó con 15 ml de ácido acético (5% v/v, pH 2,.5 vía rectal en única dosis. Finalmente se extrajeron los colon para su evaluación histopatológica. Resultados: El grupo tratado con extracto (3800mg/kg presenta menores lesiones macroscópicas en la mucosa comparado con el control. (p<0,.05; Kruskal-Wallis. A nivel microscópico se obtuvo que la mayor diferencia fue entre el grupo control y el grupo 4 (3800mg/kg. (p<0.05; Kruskal-Wallis, Test de Dunn. Conclusiones: El extracto de Tabebuia serratifolia tiene un efecto protector sobre la colitis aguda inducida en ratones Balb-c machos, siendo la dosis de extracto de 3800 mg/kg de peso la de mayor efecto.Palabras Clave: Colitis ulcerosa, ácido acético, agente antiinflamatorio, Tabebuia serratifolia.

  8. EFECTO PREVENTIVO DE LA Tabebuia serratifolia (Palo de Arco EN UN MODELO MURINO DE COLITIS AGUDA INDUCIDA CON ÁCIDO ACÉTICO EN RATONES BALB-C MACHOS

    Directory of Open Access Journals (Sweden)

    Juan Nivin-Huerta

    2013-01-01

    Full Text Available Objetivo: Determinar el efecto preventivo de la Tabebuia serratifolia en la colitis aguda inducida por ácido acético en ratones Balb/c. Métodos: Diseño: estudio experimental incompleto. Lugar: Instituto de Patología de la Universidad Nacional de San Marcos (Lima, Perú. Participantes: Ratones machos de la cepa balb/c. Intervenciones: Se administró extracto hidroalcohólico de Tabebuia serratifolia vía orogástrica por 4 días a 48 ratones distribuidos aleatoriamente en 6 grupos. La inducción se realizó con 15 ml de ácido acético (5% v/v, pH 2,.5 vía rectal en única dosis. Finalmente se extrajeron los colon para su evaluación histopatológica. Resultados: El grupo tratado con extracto (3800mg/kg presenta menores lesiones macroscópicas en la mucosa comparado con el control. (p<0,.05; Kruskal-Wallis. A nivel microscópico se obtuvo que la mayor diferencia fue entre el grupo control y el grupo 4 (3800mg/kg. (p<0.05; Kruskal-Wallis, Test de Dunn. Conclusiones: El extracto de Tabebuia serratifolia tiene un efecto protector sobre la colitis aguda inducida en ratones Balb-c machos, siendo la dosis de extracto de 3800 mg/kg de peso la de mayor efecto.

  9. Flora bucal en perros de la raza Beagle con enfermedad periodontal inducida

    Directory of Open Access Journals (Sweden)

    Cabrera García, Alexei

    2012-01-01

    Full Text Available ResumenLa enfermedad periodontal afecta a los perros durante toda su vida y se debe a la acumulación de placa dental bacteriana en las coronas dentales a lo largo de la encía, lo que conlleva a una reacción inflamatoria de la misma, conocida como gingivitis. Con el fin determinar la flora bucal en perros con enfermedad periodontal inducida se estudiaron 10 canes de la raza Beagle que previamente fueron sometidos a una intervención quirúrgica para inducir la enfermedad.SummaryPeriodontal diseases affect the dogs all its life and this is due to the accumulation of bacterial dental plaque along the gums as results this provokes a well known inflammatory reaction defined as gingivitis. The purpose of this paper was to determine the bucal flora in dogs with periodontal disease induced.

  10. A fully-discrete finite element approximation for the eddy currents problem Un esquema completamente discreto basado en elementos finitos para el problema de corrientes inducidas

    Directory of Open Access Journals (Sweden)

    Ramiro Acevedo

    2013-03-01

    Full Text Available The eddy current model is obtained from Maxwell’s equations by neglecting the displacement currents in the Amp`ere-Maxwell’s law and it is commonly used in many problems in sciences, engineering and industry (e.g, in induction heating, electromagnetic braking, and power transformers. The so-called “A, V −A potential formulation” (B´ır´o & Preis [1] is nowadays one of the most accepted formulations to solve the eddy current equations numerically, and B´ır´o & Valli [2] have recently provided its well-posedness and convergence analysis for the time-harmonic eddy current problem. The aim of this paper is to extend the analysis performed by B´ır´o & Valli to the general transient eddy current model. We provide a backward-Euler fully-discrete approximation based on nodal finite elements and we show that the resulting discrete variational problem is well posed. Furthermore, error estimates that prove optimal convergence are settled.El modelo de corrientes inducidas se obtiene a partir de las ecuaciones de Maxwell, despreciando las corrientes de desplazamiento de la Ley de AmpèreMaxwell. Bíró & Valli realizaron recientemente el análisis de existencia y unicidad de solución y el análisis teórico de convergencia para una de las formulaciones más populares del problema de corrientes inducidas en regimen armónico, conocida como “formulación en potenciales A; V A”. En el presente artículo se extiende el análisis realizado por Bíró & Valli al modelo evolutivo general de corrientes inducidas. Presentamos un esquema completamente discreto para la formulación, basado en una aproximación temporal usando un método de Euler implícito y una aproximación espacial a través del método de elementos finitos. Además, demostramos que el problema discreto resultante es un problema bien planteado y obtenemos estimaciones del error que muestran convergencia óptima.

  11. AxonSeg: Open Source Software for Axon and Myelin Segmentation and Morphometric Analysis.

    Science.gov (United States)

    Zaimi, Aldo; Duval, Tanguy; Gasecka, Alicja; Côté, Daniel; Stikov, Nikola; Cohen-Adad, Julien

    2016-01-01

    Segmenting axon and myelin from microscopic images is relevant for studying the peripheral and central nervous system and for validating new MRI techniques that aim at quantifying tissue microstructure. While several software packages have been proposed, their interface is sometimes limited and/or they are designed to work with a specific modality (e.g., scanning electron microscopy (SEM) only). Here we introduce AxonSeg, which allows to perform automatic axon and myelin segmentation on histology images, and to extract relevant morphometric information, such as axon diameter distribution, axon density and the myelin g-ratio. AxonSeg includes a simple and intuitive MATLAB-based graphical user interface (GUI) and can easily be adapted to a variety of imaging modalities. The main steps of AxonSeg consist of: (i) image pre-processing; (ii) pre-segmentation of axons over a cropped image and discriminant analysis (DA) to select the best parameters based on axon shape and intensity information; (iii) automatic axon and myelin segmentation over the full image; and (iv) atlas-based statistics to extract morphometric information. Segmentation results from standard optical microscopy (OM), SEM and coherent anti-Stokes Raman scattering (CARS) microscopy are presented, along with validation against manual segmentations. Being fully-automatic after a quick manual intervention on a cropped image, we believe AxonSeg will be useful to researchers interested in large throughput histology. AxonSeg is open source and freely available at: https://github.com/neuropoly/axonseg.

  12. Axonal interferon responses and alphaherpesvirus neuroinvasion

    Science.gov (United States)

    Song, Ren

    Infection by alphaherpesviruses, including herpes simplex virus (HSV) and pseudorabies virus (PRV), typically begins at a peripheral epithelial surface and continues into the peripheral nervous system (PNS) that innervates this tissue. Inflammatory responses are induced at the infected peripheral site prior to viral invasion of the PNS. PNS neurons are highly polarized cells with long axonal processes that connect to distant targets. When the peripheral tissue is first infected, only the innervating axons are exposed to this inflammatory milieu, which include type I interferon (e.g. IFNbeta) and type II interferon (i.e. IFNgamma). IFNbeta can be produced by all types of cells, while IFNgamma is secreted by some specific types of immune cells. And both types of IFN induce antiviral responses in surrounding cells that express the IFN receptors. The fundamental question is how do PNS neurons respond to the inflammatory milieu experienced only by their axons. Axons must act as potential front-line barriers to prevent PNS infection and damage. Using compartmented cultures that physically separate neuron axons from cell bodies, I found that pretreating isolated axons with IFNbeta or IFNgamma significantly diminished the number of HSV-1 and PRV particles moving from axons to the cell bodies in an IFN receptor-dependent manner. Furthermore, I found the responses in axons are activated differentially by the two types of IFNs. The response to IFNbeta is a rapid, axon-only response, while the response to IFNgamma involves long distance signaling to the PNS cell body. For example, exposing axons to IFNbeta induced STAT1 phosphorylation (p-STAT1) only in axons, while exposure of axons to IFNgamma induced p-STAT1 accumulation in distant cell body nuclei. Blocking transcription in cell bodies eliminated IFNgamma-, but not IFNbeta-mediated antiviral effects. Proteomic analysis of IFNbeta- or IFNgamma-treated axons identified several differentially regulated proteins. Therefore

  13. Cable energy function of cortical axons.

    Science.gov (United States)

    Ju, Huiwen; Hines, Michael L; Yu, Yuguo

    2016-01-01

    Accurate estimation of action potential (AP)-related metabolic cost is essential for understanding energetic constraints on brain connections and signaling processes. Most previous energy estimates of the AP were obtained using the Na(+)-counting method, which seriously limits accurate assessment of metabolic cost of ionic currents that underlie AP conduction along the axon. Here, we first derive a full cable energy function for cortical axons based on classic Hodgkin-Huxley (HH) neuronal equations and then apply the cable energy function to precisely estimate the energy consumption of AP conduction along axons with different geometric shapes. Our analytical approach predicts an inhomogeneous distribution of metabolic cost along an axon with either uniformly or nonuniformly distributed ion channels. The results show that the Na(+)-counting method severely underestimates energy cost in the cable model by 20-70%. AP propagation along axons that differ in length may require over 15% more energy per unit of axon area than that required by a point model. However, actual energy cost can vary greatly depending on axonal branching complexity, ion channel density distributions, and AP conduction states. We also infer that the metabolic rate (i.e. energy consumption rate) of cortical axonal branches as a function of spatial volume exhibits a 3/4 power law relationship.

  14. Motor axon excitability during Wallerian degeneration

    DEFF Research Database (Denmark)

    Moldovan, Mihai; Alvarez, Susana; Krarup, Christian

    2008-01-01

    , action potential propagation and structural integrity of the distal segment are maintained. The aim of this study was to investigate in vivo the changes in membrane function of motor axons during the 'latent' phase of Wallerian degeneration. Multiple indices of axonal excitability of the tibial nerve...

  15. Commissural axons of the mouse cochlear nucleus.

    Science.gov (United States)

    Brown, M Christian; Drottar, Marie; Benson, Thane E; Darrow, Keith

    2013-05-01

    The axons of commissural neurons that project from one cochlear nucleus to the other were studied after labeling with anterograde tracer. Injections were made into the dorsal subdivision of the cochlear nucleus in order to restrict labeling only to the group of commissural neurons that gave off collaterals to, or were located in, this subdivision. The number of labeled commissural axons in each injection was correlated with the number of labeled radiate multipolar neurons, suggesting radiate neurons as the predominant origin of the axons. The radiate commissural axons are thick and myelinated, and they exit the dorsal acoustic stria of the injected cochlear nucleus to cross the brainstem in the dorsal half, near the crossing position of the olivocochlear bundle. They enter the opposite cochlear nucleus via the dorsal and ventral acoustic stria and at its medial border. Reconstructions of single axons demonstrate that terminations are mostly in the core and typically within a single subdivision of the cochlear nucleus. Extents of termination range from narrow to broad along both the dorsoventral (i.e., tonotopic) and the rostrocaudal dimensions. In the electron microscope, labeled swellings form synapses that are symmetric (in that there is little postsynaptic density), a characteristic of inhibitory synapses. Our labeled axons do not appear to include excitatory commissural axons that end in edge regions of the nucleus. Radiate commissural axons could mediate the broadband inhibition observed in responses to contralateral sound, and they may balance input from the two ears with a quick time course.

  16. El efecto protector de la Melatonina en la cirrosis hepática experimental inducida por Tioacetamida

    OpenAIRE

    Torres Tordera, Eva María

    2011-01-01

    La cirrosis hepática es una enfermedad crónica que puede provocar fallo hepático, hipertensión portal y hepatocarcinoma. Esta relacionada con una elevada morbimortalidad y esto puede ser debido a virus, agentes tóxicos, anormalidades genéticas, trastornos inmunológicos, etc. La fibrosis resulta de la activación de sustancias de células como citoquinas y stress oxidativo. La inducción de stress oxidativo, disfunción mitocondrial y depleción de los niveles de antioxidantes es una caracterís...

  17. Pérdida auditiva inducida por ruido en estudiantes de la carrera de odontología

    OpenAIRE

    2013-01-01

    Introducción: Los odontólogos se exponen desde su formación universitaria a sonidos potencialmente dañinos en forma rutinaria. Objetivo: Determinar si la presencia de escotoma en las frecuencias 3,4 y 6 kHz está asociada a la exposición a ruido de implementos dentales. Material y método: Se realizó un estudio de corte transversal en estudiantes expuestos a ruido en sus actividades prácticas dentales y otro grupo no expuesto. Se realizaron evaluaciones auditivas a ambos grupos, además de una s...

  18. Lesiones en órganos de cerdos posdestete, inducidas por el lipopolisacárido de E. coli

    OpenAIRE

    2013-01-01

    RESUMENObjetivo. Evaluar el efecto de la ingestión de varios niveles de Lipopolisacárido (LPS) de E. coli sobre las manifestaciones clínicas y lesiones en órganos de cerdos recién destetados. Materiales y métodos. El trabajo de campo se realizó en el Centro San Pablo, perteneciente a la Universidad Nacional de Colombia. El estudio se realizó con 52 cerdos destetados (6.5±0.5 kg) a los 21 días de edad. Los animales fueron alimentados durante 10 días con una dieta basal compuesta de leche y alg...

  19. Lesiones en órganos de cerdos posdestete, inducidas por el lipopolisacárido de E. coli

    Directory of Open Access Journals (Sweden)

    Cristian Gutiérrez V.

    2013-08-01

    Full Text Available Objetivo. Evaluar el efecto de la ingestión de varios niveles de Lipopolisacárido (LPS de E. coli sobre las manifestaciones clínicas y lesiones en órganos de cerdos recién destetados. Materiales y métodos. El trabajo de campo se realizó en el Centro San Pablo, perteneciente a la Universidad Nacional de Colombia. El estudio se realizó con 52 cerdos destetados (6.5±0.5 kg a los 21 días de edad. Los animales fueron alimentados durante 10 días con una dieta basal compuesta de leche y algunos de sus derivados, adicionada con cuatro niveles de LPS (0, 0.3, 0.5 y 1.0 μg/ml de alimento. Los cerdos se sacrificaron escalonadamente los días 1, 5, 7 y 10 posdestete y se tomaron muestras de intestino delgado, estómago, hígado, páncreas, corazón, pulmón, riñón y bazo. El monitoreo clínico y paraclínico se realizó diariamente durante la investigación. Para determinar la ganancia de peso, los animales fueron pesados el día del destete y el día del sacrificio. Resultados. Hubo diferencia (p<0.01 en las variables peso de los órganos y ganancia de peso, donde los animales que consumieron el mayor nivel de LPS presentaron los menores valores, llegando a su mínimo nivel el día 10 posdestete. Las variables presentación de: lesiones macroscópicas, diarreas, y temperatura rectal, aumentaron con el nivel de inclusión de LPS en la dieta, llegando a su máximo nivel el día 10 posdestete (p<0.01. Conclusiones. El LPS de E. coli provoca la inhibición del crecimiento corporal y de los órganos en estudio y una alta incidencia de diarreas.

  20. Estudio histológico de agallas inducidas por artrópodos en algunas especies de compositae

    Directory of Open Access Journals (Sweden)

    Villazón de Pinzón Eucariz

    1989-06-01

    Full Text Available En el presente trabajo se analizan las alteraciones tisulares de las hojas con agallas de tres especies de Compositae. Este estudio fue realizado mediante cortes histológicos (secciones transversales de las hojas, con el fin de determinar los cambios morfológicos de las células cecídíanas con relación a los tejidos que constituyen el órgano sano de la planta. Se observó un aumento desmesurado en el número de capas celulares del parénquima espunjoso (híperplasía, las cuales se disponen principalmente alrededor de la cavidad larvaria para formar el tejido que servirá de alimento al parásito.

  1. Efecto de la cafeína sobre las lesiones inducidas por nitrosoguanidina y luz ultravioleta en Phycomyces blakesleeanus

    OpenAIRE

    Díaz Minguez, J. M.; Iturriaga, E A; Eslava, A. P.

    1988-01-01

    [EN] Caffeine, a regular component of the diet for most people, enhances the lethal and mutagenic effects of various DNA-damaging agents in many prokaryote and eukaryote organismm. A wild type strain and two auxotrophic strains of the zygomycete Phycomyces blakesleeanus were tested for enhancement of UV-inactivation and MNNG-inactivation and mutagenesis by caffeine in growth medium. Results show that caffeine interferes with a non light-dependent DNA repair mechanism, presumably a recombinati...

  2. RESPUESTAS ADAPTATIVAS A LA SEQUÍA EN EL TOMATE INDUCIDAS POR OSMOACONDICIONAMIENTO DE PLÁNTULAS

    Directory of Open Access Journals (Sweden)

    J. M. Dell'Amico

    2006-01-01

    Full Text Available El trabajo se realizó con el objetivo de aumentar el nivel de tolerancia a la sequía del tomate mediante tratamientos de osmoacondicionamiento, para inducir la capacidad natural de las plantas de adaptarse a condiciones adversas y que pueda ser considerada como una tolerancia adquirida. En el trabajo, se realizaron dos ensayos con plántulas de tomate cv Amalia. En el primero se comprobó la viabilidad del método y se realizaron evaluaciones de crecimiento y reparto de biomasa a nivel de plantas jóvenes. En el segundo ensayo, se evaluó el efecto de los mismos tratamientos adaptativos en la respuesta de las plantas cultivadas en condiciones de secano severo y su comportamiento agronómico. Se analizaron el reparto de biomasa entre la parte aérea y raíz, la conductancia estomática y el rendimiento. Los tratamientos de osmoacondicionamiento en plántulas de tomate indujeron cambios cuantitativos en una serie de respuestas fisiológicas adaptativas a lo largo de su ciclo biológico, que se tradujeron en mejoras agronómicas en condiciones de sequía, como fueron: aumento de la biomasa total de las plantas, mayor rendimiento, incremento de la relación raíz/parte aérea y mejoras de las relaciones hídricas o mayor conductancia estomática. Evidentemente los resultados ponen de manifiesto la posibilidad de incrementar los rendimientos agronómicos del tomate en condiciones de sequía, mediante la inducción de su capacidad adaptativa durante la fase de pos-germinación de la semilla.

  3. Ascending Midbrain Dopaminergic Axons Require Descending GAD65 Axon Fascicles for Normal Pathfinding

    Directory of Open Access Journals (Sweden)

    Claudia Marcela Garcia-Peña

    2014-06-01

    Full Text Available The Nigrostriatal pathway (NSP is formed by dopaminergic axons that project from the ventral midbrain to the dorsolateral striatum as part of the medial forebrain bundle. Previous studies have implicated chemotropic proteins in the formation of the NSP during development but little is known of the role of substrate-anchored signals in this process. We observed in mouse and rat embryos that midbrain dopaminergic axons ascend in close apposition to descending GAD65-positive axon bundles throughout their trajectory to the striatum. To test whether such interaction is important for dopaminergic axon pathfinding, we analyzed transgenic mouse embryos in which the GAD65 axon bundle was reduced by the conditional expression of the diphtheria toxin. In these embryos we observed dopaminergic misprojection into the hypothalamic region and abnormal projection in the striatum. In addition, analysis of Robo1/2 and Slit1/2 knockout embryos revealed that the previously described dopaminergic misprojection in these embryos is accompanied by severe alterations in the GAD65 axon scaffold. Additional studies with cultured dopaminergic neurons and whole embryos suggest that NCAM and Robo proteins are involved in the interaction of GAD65 and dopaminergic axons. These results indicate that the fasciculation between descending GAD65 axon bundles and ascending dopaminergic axons is required for the stereotypical NSP formation during brain development and that known guidance cues may determine this projection indirectly by instructing the pathfinding of the axons that are part of the GAD65 axon scaffold.

  4. Early events in axon/dendrite polarization.

    Science.gov (United States)

    Cheng, Pei-lin; Poo, Mu-ming

    2012-01-01

    Differentiation of axons and dendrites is a critical step in neuronal development. Here we review the evidence that axon/dendrite formation during neuronal polarization depends on the intrinsic cytoplasmic asymmetry inherited by the postmitotic neuron, the exposure of the neuron to extracellular chemical factors, and the action of anisotropic mechanical forces imposed by the environment. To better delineate the functions of early signals among a myriad of cellular components that were shown to influence axon/dendrite formation, we discuss their functions by distinguishing their roles as determinants, mediators, or modulators and consider selective degradation of these components as a potential mechanism for axon/dendrite polarization. Finally, we examine whether these early events of axon/dendrite formation involve local autocatalytic activation and long-range inhibition, as postulated by Alan Turing for the morphogenesis of patterned biological structure.

  5. Dynamics of mitochondrial transport in axons

    Directory of Open Access Journals (Sweden)

    Robert Francis Niescier

    2016-05-01

    Full Text Available The polarized structure and long neurites of neurons pose a unique challenge for proper mitochondrial distribution. It is widely accepted that mitochondria move from the cell body to axon ends and vice versa; however, we have found that mitochondria originating from the axon ends moving in the retrograde direction never reach to the cell body, and only a limited number of mitochondria moving in the anterograde direction from the cell body arrive at the axon ends of mouse hippocampal neurons. Furthermore, we have derived a mathematical formula using the Fokker-Planck equation to characterize features of mitochondrial transport, and the equation could determine altered mitochondrial transport in axons overexpressing parkin. Our analysis will provide new insights into the dynamics of mitochondrial transport in axons of normal and unhealthy neurons.

  6. Variabilidad del intervalo de ciclo de las taquicardias ventriculares con igual morfología inducidas en estudio electrofisiológico

    Directory of Open Access Journals (Sweden)

    Abdel J. Fuenmayor

    2004-01-01

    Full Text Available Introducción: La determinación de la variabilidad espontánea del intervalo de ciclo de las taquicardias ventriculares es fundamental para interpretar los efectos de tratamientos y para programar dispositivos anti-taquicardia. Objetivo: Estudiar la variabilidad espontánea del intervalo de ciclo de las taquicardias ventriculares producidas por re-entrada. Métodos: Incluimos 22 pacientes (12 varones de 52 + 18 años de edad, en quienes se indujeron 121 taquicardias ventriculares monomórficas sostenidas. Las taquicardias inducidas en un mismo paciente tenían la misma morfología y eran producidas por re-entrada. Resultados: En promedio, las taquicardias ventriculares tenían un intervalo de ciclo de 318 + 39 milisegundos (mseg. La desviación típica del promedio de los intervalos de ciclo de las taquicardias ventriculares de igual morfología inducidas en cada paciente (variación inter-taquicardia fue 10,91 + 9,63 mseg. La diferencia promedio entre el R-R máximo y el R-R mínimo (variación inter-taquicardia fue de 26,15 mseg. La variación intra-taquicardia (desviación típica de los 10 ciclos que fueron promediados fue de 5,78 + 2,40 mseg (2,58 - 15,05. El sexo, la etiología y la edad no determinaron diferencias en la frecuencia cardíaca durante e la taquicardia. Conclusión: En este grupo de pacientes, las taquicardias ventriculares de re-entrada originadas en un mismo circuito y en un mismo paciente muestran poca variación del intervalo de ciclo. Esta estabilidad relativa debe tenerse presente al considerar efectos terapéuticos, programar dispositivos anti-taquicardia y estudiar los factores relacionados con la variabilidad misma.Introduction: Th e spontaneous variability in ventricular tachycardia cycle length should be known for the proper assessment of pharmacological treatment and anti-tachycardia devices programming. Objective: To assess the ventricular tachycardia (VT rate variability of patients with re-entrant VTs induced

  7. Laser-based single-axon transection for high-content axon injury and regeneration studies.

    Directory of Open Access Journals (Sweden)

    Darío Kunik

    Full Text Available The investigation of the regenerative response of the neurons to axonal injury is essential to the development of new axoprotective therapies. Here we study the retinal neuronal RGC-5 cell line after laser transection, demonstrating that the ability of these cells to initiate a regenerative response correlates with axon length and cell motility after injury. We show that low energy picosecond laser pulses can achieve transection of unlabeled single axons in vitro and precisely induce damage with micron precision. We established the conditions to achieve axon transection, and characterized RGC-5 axon regeneration and cell body response using time-lapse microscopy. We developed an algorithm to analyze cell trajectories and established correlations between cell motility after injury, axon length, and the initiation of the regeneration response. The characterization of the motile response of axotomized RGC-5 cells showed that cells that were capable of repair or regrowth of damaged axons migrated more slowly than cells that could not. Moreover, we established that RGC-5 cells with long axons could not recover their injured axons, and such cells were much more motile. The platform we describe allows highly controlled axonal damage with subcellular resolution and the performance of high-content screening in cell cultures.

  8. Reproducción inducida de Pimelodus pictus con extracto de hipófisis de carpa (EHC y Ovaprim®

    Directory of Open Access Journals (Sweden)

    Elizabeth Aya B

    2011-04-01

    Full Text Available Objetivo. Comparar la respuesta a la maduración final de las ova y la tasa de ovulación usando dos tratamientos hormonales en hembras de Pimelodus pictus. Materiales y métodos. Hembras maduras recién capturadas fueron superestimuladas con Extracto de Hipófisis de Carpa (EHC y mezcla del análogo de la hormona liberadora de la gonadotropina de salmón más domperidona, Ovaprim®. Se utilizaron dosis totales de 5.5 y 7.7 mg/kg, y 0.5 y 1 ml/kg respectivamente, dividida en dos dosis, e inyectadas con un intervalo de 12 h (10% de la dosis total en la primera inyección y 90% en la segunda. Resultados. Con tiempo de latencia de 6 h 30±20 min a 27.4±0.2°C. Las hembras en todos los tratamientos respondieron por sobre el 50%, siendo mayor la respuesta en ambos protocolos para EHC (p<0.05. El diámetro ovocitario durante y después de los tratamientos aumentó en todos los casos, siendo mayor y diferente (p<0.05, para los tratamientos con Ovaprim®. La fecundidad se registró entre 818 a 1185 óvulos/hembra. Conclusiones. Se demuestra las posibilidades de reproducción inducida con dos inductores hormonales, siendo EHC superior a Ovaprim®.

  9. Caracterización biológica del virus del mosaico de la sida de Sinaloa: transmisión por semilla, rango de hospedantes y asociación con partículas subvirales

    OpenAIRE

    Domínguez Durán, Gustavo

    2014-01-01

    En México la horticultura es una de las actividades de primordial importancia, tanto por la generación de divisas como por la generación de empleos; sin embargo, existen diferentes plagas y enfermedades que afectan su producción, siendo estas últimas el principal factor limitante, destacando las inducidas por los virus por su impacto en rendimiento y calidad en frutos. Los begomovirus infectan plantas dicotiledóneas, son trasmitidos por mosquita blanca y su genoma puede ser ...

  10. Axon initial segment Kv1 channels control axonal action potential waveform and synaptic efficacy.

    Science.gov (United States)

    Kole, Maarten H P; Letzkus, Johannes J; Stuart, Greg J

    2007-08-16

    Action potentials are binary signals that transmit information via their rate and temporal pattern. In this context, the axon is thought of as a transmission line, devoid of a role in neuronal computation. Here, we show a highly localized role of axonal Kv1 potassium channels in shaping the action potential waveform in the axon initial segment (AIS) of layer 5 pyramidal neurons independent of the soma. Cell-attached recordings revealed a 10-fold increase in Kv1 channel density over the first 50 microm of the AIS. Inactivation of AIS and proximal axonal Kv1 channels, as occurs during slow subthreshold somatodendritic depolarizations, led to a distance-dependent broadening of axonal action potentials, as well as an increase in synaptic strength at proximal axonal terminals. Thus, Kv1 channels are strategically positioned to integrate slow subthreshold signals, providing control of the presynaptic action potential waveform and synaptic coupling in local cortical circuits.

  11. Hipotermia moderada activa inducida en la agresión hipóxico-hisquémica

    OpenAIRE

    Martínez Tarrero, Cristina

    2016-01-01

    La encefalopatía hipóxico-isquémica es definida como la deficiencia en el aporte de oxígeno y/o perfusión sanguínea adecuada al cerebro del neonato durante el periparto. Se considera una de las principales causas de morbimortalidad neonatal, teniéndolo en cuenta como un problema sociosanitario. A principios del siglo XX su tratamiento era sintomático, realizándose ahora terapias neuroprotectoras tales como la hipotermia activa moderada inducida. Esta terapia consiste en disminuir la temperatu...

  12. Genetics Home Reference: giant axonal neuropathy

    Science.gov (United States)

    ... R. Proteomic analysis in giant axonal neuropathy: new insights into disease mechanisms. Muscle Nerve. 2012 Aug;46( ... healthcare professional . About Genetics Home Reference Site Map Customer Support Selection Criteria for Links USA.gov Copyright ...

  13. Genetic dissection of myelinated axons in zebrafish

    OpenAIRE

    2009-01-01

    In the vertebrate nervous system, the myelin sheath allows for rapid and efficient conduction of action potentials along axons. Despite the essential function of myelin, many questions remain unanswered about the mechanisms that govern the development of myelinated axons. The fundamental properties of myelin are widely shared among vertebrates, and the zebrafish has emerged as a powerful system to study myelination in vivo. This review will highlight recent advances from genetic screens in ze...

  14. Crossing axons in the third nerve nucleus.

    Science.gov (United States)

    Bienfang, D C

    1975-12-01

    The research presented in this paper studied the pathway taken by the crossed fibers of the third nerve nucleus in an animal whose nucleus has been well mapped and found to correlate well with higher mammals and man. Autoradiography using tritiated amino acid labeled the cell bodies an axons of the left side of the oculomotor nucleus of the cat. Axons so labeled could be seen emerging from the ventral portion of the left nucleus through the median longitudinal fasciculus (mlf) to join the left oculomotor nerve. Labeled axons were also seen to emerge from the medial border of the caudal left nucleus, cross the midline, and pass through the right nucleus and the right mlf to join the right oculomotor nerve. These latter axons must be the crossed axons of the superior rectus and levator palpebrae subnuclei. Since the path of these crossed axons is through the caudal portion of the nucleus of the opposite side, the destruction of one lateral half of the oculomotor nucleus would result in a bilateral palsy of the crossed subnuclei. Bilateral palsy of the superior rectus and bilateral assymetrical palsy of the levator palpebrae muscles would result.

  15. Nefropatía por contraste en el síndrome coronario agudo

    OpenAIRE

    Mariana Carnevalini; Mariano Giorgi; Silvina Waldman; Nicolás Caturla; Rodrigo Ovejero; Estela Falconi; Lucas San Miguel; Christian Caroli; Eduardo Magariños; Hernán Cohen Arazi

    2011-01-01

    La nefropatía inducida por contraste (NIC) es una de las causas más frecuentes de insuficiencia renal en pacientes internados. En el síndrome coronario agudo (SCA), la presencia de NIC aumenta la morbimortalidad. Las medidas de profilaxis y los factores de riesgo intervinientes de NIC en SCA no han sido determinados con exactitud. El objetivo de este estudio fue evaluar la incidencia de NIC y los factores asociados a su desarrollo en pacientes ingresados en unidad coronaria con requerimiento ...

  16. Estrés oxidativo y otras respuestas fisiológicas inducidas por el alpeorujo transformado por hongos saprobios en plantas de tomate (Solanum lycopersicum L.)

    OpenAIRE

    García Sánchez, Mercedes

    2013-01-01

    El cultivo del olivar y la obtención industrial de aceite de oliva tienen una extraordinaria importancia económica y social en España y, particularmente, en Andalucía. Actualmente, el sistema de extracción de aceite de oliva es la centrifugación de dos fases tras el que se obtiene una fase oleosa o aceite y un residuo semisólido denominado alpeorujo. Se ha observado, que el alpeorujo presenta un elevado contenido en materia orgánica, nutrientes minerales y un pH ligeramente ácido lo que plant...

  17. Axon injury triggers EFA-6 mediated destabilization of axonal microtubules via TACC and doublecortin like kinase.

    Science.gov (United States)

    Chen, Lizhen; Chuang, Marian; Koorman, Thijs; Boxem, Mike; Jin, Yishi; Chisholm, Andrew D

    2015-09-04

    Axon injury triggers a series of changes in the axonal cytoskeleton that are prerequisites for effective axon regeneration. In Caenorhabditis elegans the signaling protein Exchange Factor for ARF-6 (EFA-6) is a potent intrinsic inhibitor of axon regrowth. Here we show that axon injury triggers rapid EFA-6-dependent inhibition of axonal microtubule (MT) dynamics, concomitant with relocalization of EFA-6. EFA-6 relocalization and axon regrowth inhibition require a conserved 18-aa motif in its otherwise intrinsically disordered N-terminal domain. The EFA-6 N-terminus binds the MT-associated proteins TAC-1/Transforming-Acidic-Coiled-Coil, and ZYG-8/Doublecortin-Like-Kinase, both of which are required for regenerative growth cone formation, and which act downstream of EFA-6. After injury TAC-1 and EFA-6 transiently relocalize to sites marked by the MT minus end binding protein PTRN-1/Patronin. We propose that EFA-6 acts as a bifunctional injury-responsive regulator of axonal MT dynamics, acting at the cell cortex in the steady state and at MT minus ends after injury.

  18. Estudio de la influencia de la refrigeracion con aire de forma natural e inducida en el comportamiento de instalaciones fotovoltaicas

    Science.gov (United States)

    Mazon Hernandez, Rocio

    panels are analysed to compare and select the best configuration. The presented research provides a deep knowledge of how they work as well as information and results for an improvement in future designs of building integrated photovoltaic systems. Este estudio se centra en analizar la influencia negativa de la temperatura en la produccion electrica de paneles fotovoltaicos al estar emplazados sobre cubierta de acero, como sucede en naves industriales y sobre un invernadero. Se estudian diferentes configuraciones que permitan refrigerar los paneles, reduciendo su temperatura y mejorar su rendimiento. Para abordar este problema, se han construido dos instalaciones experimentales, fieles a plantas solares en funcionamiento. Una instalacion engloba dos paneles fotovoltaicos sobre estructura fija al suelo. Uno de los paneles esta integrado sobre una superficie paralela y metalica. Entre ambas superficies existe un espacio que posibilita circular aire, permitiendo refrigerar el panel por conveccion natural, o conveccion forzada impulsando el aire con un ventilador. El otro panel, libre por su cara posterior y se ha considerado de referencia. Se ha estudiado el comportamiento del panel integrado sobre cubierta para diferentes secciones de aire y velocidades inducidas, comparandolo con el panel de referencia. Se ha desarrollado un modelo experimental que nos permite determinar la temperatura del panel en funcion de las variables que influyen en su refrigeracion. Adicionalmente, se han analizado los datos de una planta solar en funcionamiento, con paneles de igual caracteristicas, obteniendo correlaciones entre la temperatura del panel y las variables electricas y comparandolos con las obtenidas en la instalacion experimental. La segunda instalacion experimental reproduce parte de una instalacion solar sobre un invernadero, formada por cuatro paneles fotovoltaicos colocados sobre el plastico del invernadero, existiendo un canal divergente entre ambas superficies. Se estudia la

  19. How Schwann Cells Sort Axons: New Concepts.

    Science.gov (United States)

    Feltri, M Laura; Poitelon, Yannick; Previtali, Stefano Carlo

    2016-06-01

    Peripheral nerves contain large myelinated and small unmyelinated (Remak) fibers that perform different functions. The choice to myelinate or not is dictated to Schwann cells by the axon itself, based on the amount of neuregulin I-type III exposed on its membrane. Peripheral axons are more important in determining the final myelination fate than central axons, and the implications for this difference in Schwann cells and oligodendrocytes are discussed. Interestingly, this choice is reversible during pathology, accounting for the remarkable plasticity of Schwann cells, and contributing to the regenerative potential of the peripheral nervous system. Radial sorting is the process by which Schwann cells choose larger axons to myelinate during development. This crucial morphogenetic step is a prerequisite for myelination and for differentiation of Remak fibers, and is arrested in human diseases due to mutations in genes coding for extracellular matrix and linkage molecules. In this review we will summarize progresses made in the last years by a flurry of reverse genetic experiments in mice and fish. This work revealed novel molecules that control radial sorting, and contributed unexpected ideas to our understanding of the cellular and molecular mechanisms that control radial sorting of axons.

  20. Protein phosphorylation: Localization in regenerating optic axons

    Energy Technology Data Exchange (ETDEWEB)

    Larrivee, D. (Cornell Univ. Medical College, New York, NY (USA))

    1990-09-01

    A number of axonal proteins display changes in phosphorylation during goldfish optic nerve regeneration. (1) To determine whether the phosphorylation of these proteins was closely linked to their synthesis in the retinal ganglion cell body, cycloheximide was injected intraocularly into goldfish whose optic nerves had been regenerating for 3 weeks. Cycloheximide reduced the incorporation of (3H)proline and 32P orthophosphate into total nerve protein by 84% and 46%, respectively. Of the 20 individual proteins examined, 17 contained less than 15% of the (3H)proline label measured in corresponding controls, whereas 18 proteins contained 50% or more of the 32P label, suggesting that phosphorylation was largely independent of synthesis. (2) To determine whether the proteins were phosphorylated in the ganglion cell axons, axonal transport of proteins was blocked by intraocular injection of vincristine. Vincristine reduced (3H)proline labeling of total protein by 88% and 32P labeling by 49%. Among the individual proteins (3H)proline labeling was reduced by 90% or more in 18 cases but 32P labeling was reduced only by 50% or less. (3) When 32P was injected into the cranial cavity near the ends of the optic axons, all of the phosphoproteins were labeled more intensely in the optic tract than in the optic nerve. These results suggest that most of the major phosphoproteins that undergo changes in phosphorylation in the course of regeneration are phosphorylated in the optic axons.

  1. Automated Axon Counting in Rodent Optic Nerve Sections with AxonJ

    Science.gov (United States)

    Zarei, Kasra; Scheetz, Todd E.; Christopher, Mark; Miller, Kathy; Hedberg-Buenz, Adam; Tandon, Anamika; Anderson, Michael G.; Fingert, John H.; Abràmoff, Michael David

    2016-05-01

    We have developed a publicly available tool, AxonJ, which quantifies the axons in optic nerve sections of rodents stained with paraphenylenediamine (PPD). In this study, we compare AxonJ’s performance to human experts on 100x and 40x images of optic nerve sections obtained from multiple strains of mice, including mice with defects relevant to glaucoma. AxonJ produced reliable axon counts with high sensitivity of 0.959 and high precision of 0.907, high repeatability of 0.95 when compared to a gold-standard of manual assessments and high correlation of 0.882 to the glaucoma damage staging of a previously published dataset. AxonJ allows analyses that are quantitative, consistent, fully-automated, parameter-free, and rapid on whole optic nerve sections at 40x. As a freely available ImageJ plugin that requires no highly specialized equipment to utilize, AxonJ represents a powerful new community resource augmenting studies of the optic nerve using mice.

  2. Diverse modes of axon elaboration in the developing neocortex.

    Directory of Open Access Journals (Sweden)

    2005-08-01

    Full Text Available The development of axonal arbors is a critical step in the establishment of precise neural circuits, but relatively little is known about the mechanisms of axonal elaboration in the neocortex. We used in vivo two-photon time-lapse microscopy to image axons in the neocortex of green fluorescent protein-transgenic mice over the first 3 wk of postnatal development. This period spans the elaboration of thalamocortical (TC and Cajal-Retzius (CR axons and cortical synaptogenesis. Layer 1 collaterals of TC and CR axons were imaged repeatedly over time scales ranging from minutes up to days, and their growth and pruning were analyzed. The structure and dynamics of TC and CR axons differed profoundly. Branches of TC axons terminated in small, bulbous growth cones, while CR axon branch tips had large growth cones with numerous long filopodia. TC axons grew rapidly in straight paths, with frequent interstitial branch additions, while CR axons grew more slowly along tortuous paths. For both types of axon, new branches appeared at interstitial sites along the axon shaft and did not involve growth cone splitting. Pruning occurred via retraction of small axon branches (tens of microns, at both CR and TC axons or degeneration of large portions of the arbor (hundreds of microns, for TC axons only. The balance between growth and retraction favored overall growth, but only by a slight margin. Given the identical layer 1 territory upon which CR and TC axons grow, the differences in their structure and dynamics likely reflect distinct intrinsic growth programs for axons of long projection neurons versus local interneurons.

  3. Neural Progenitor Cells Promote Axonal Growth and Alter Axonal mRNA Localization in Adult Neurons

    Science.gov (United States)

    Merianda, Tanuja T.; Jin, Ying

    2017-01-01

    Abstract The inhibitory environment of the spinal cord and the intrinsic properties of neurons prevent regeneration of axons following CNS injury. However, both ascending and descending axons of the injured spinal cord have been shown to regenerate into grafts of embryonic neural progenitor cells (NPCs). Previous studies have shown that grafts composed of glial-restricted progenitors (GRPs) and neural-restricted progenitors (NRPs) can provide a permissive microenvironment for axon growth. We have used cocultures of adult rat dorsal root ganglion (DRG) neurons together with NPCs, which have shown significant enhancement of axon growth by embryonic rat GRP and GRPs/NRPs, both in coculture conditions and when DRGs are exposed to conditioned medium from the NPC cultures. This growth-promoting effect of NPC-conditioned medium was also seen in injury-conditioned neurons. DRGs cocultured with GRPs/NRPs showed altered expression of regeneration-associated genes at transcriptional and post-transcriptional levels. We found that levels of GAP-43 mRNA increased in DRG cell bodies and axons. However, hepcidin antimicrobial peptide (HAMP) mRNA decreased in the cell bodies of DRGs cocultured with GRPs/NRPs, which is distinct from the increase in cell body HAMP mRNA levels seen in DRGs after injury conditioning. Endogenous GAP-43 and β-actin mRNAs as well as reporter RNAs carrying axonally localizing 3'UTRs of these transcripts showed significantly increased levels in distal axons in the DRGs cocultured with GRPs/NRPs. These results indicate that axon growth promoted by NPCs is associated not only with enhanced transcription of growth-associated genes but also can increase localization of some mRNAs into growing axons. PMID:28197547

  4. Myelin-associated glycoprotein and its axonal receptors.

    Science.gov (United States)

    Schnaar, Ronald L; Lopez, Pablo H H

    2009-11-15

    Myelin-associated glycoprotein (MAG) is expressed on the innermost myelin membrane wrap, directly apposed to the axon surface. Although it is not required for myelination, MAG enhances long-term axon-myelin stability, helps to structure nodes of Ranvier, and regulates the axon cytoskeleton. In addition to its role in axon-myelin stabilization, MAG inhibits axon regeneration after injury; MAG and a discrete set of other molecules on residual myelin membranes at injury sites actively signal axons to halt elongation. Both the stabilizing and the axon outgrowth inhibitory effects of MAG are mediated by complementary MAG receptors on the axon surface. Two MAG receptor families have been described, sialoglycans (specifically gangliosides GD1a and GT1b) and Nogo receptors (NgRs). Controversies remain about which receptor(s) mediates which of MAG's biological effects. Here we review the findings and challenges in associating MAG's biological effects with specific receptors.

  5. The pathophysiology of axonal transport in alzheimer’s disease

    OpenAIRE

    Vicario Orri, Elena; Opazo, Carlos; Muñoz López, Francisco José, 1964-

    2015-01-01

    Neurons communicate in the nervous system by carrying out information along the length of their axons to finally transmit it at the synapse. Proper function of axons and axon terminals relies on the transport of proteins, organelles, vesicles, and other elements from the site of synthesis in the cell body. Conversely, neurotrophins secreted from axonal targets and other components at nerve terminals need to travel toward the cell body for clearance. Molecular motors, namely kinesins and dynei...

  6. Modeling molecular mechanisms in the axon

    Science.gov (United States)

    de Rooij, R.; Miller, K. E.; Kuhl, E.

    2017-03-01

    Axons are living systems that display highly dynamic changes in stiffness, viscosity, and internal stress. However, the mechanistic origin of these phenomenological properties remains elusive. Here we establish a computational mechanics model that interprets cellular-level characteristics as emergent properties from molecular-level events. We create an axon model of discrete microtubules, which are connected to neighboring microtubules via discrete crosslinking mechanisms that obey a set of simple rules. We explore two types of mechanisms: passive and active crosslinking. Our passive and active simulations suggest that the stiffness and viscosity of the axon increase linearly with the crosslink density, and that both are highly sensitive to the crosslink detachment and reattachment times. Our model explains how active crosslinking with dynein motors generates internal stresses and actively drives axon elongation. We anticipate that our model will allow us to probe a wide variety of molecular phenomena—both in isolation and in interaction—to explore emergent cellular-level features under physiological and pathological conditions.

  7. A Microfluidics Approach to Investigate Axon Guidance

    Science.gov (United States)

    2007-03-26

    coat the substrate with PLL. The cells of one dissociated embryonic spinal cord was re-suspended in 3 µl of freshly-prepared Modified Frog Ringer’s...Surround repulsion of spinal sensory axons in higher vertebrate embryos . Neuron 18, 889-897 (1997). 8. Colamarino, S. & Tessier-Lavigne, M. The

  8. Mechanisms of axon degeneration: from development to disease.

    Science.gov (United States)

    Saxena, Smita; Caroni, Pico

    2007-10-01

    Axon degeneration is an active, tightly controlled and versatile process of axon segment self-destruction. Although not involving cell death, it resembles apoptosis in its logics. It involves three distinct steps: induction of competence in specific neurons, triggering of degeneration at defined axon segments of competent neurons, and rapid fragmentation and removal of the segments. The mechanisms that initiate degeneration are specific to individual settings, but the final pathway of pruning is shared; it involves microtubule disassembly, axon swellings, axon fragmentation, and removal of the remnants by locally recruited phagocytes. The tight regulatory properties of axon degeneration distinguish it from passive loss phenomena, and confer significance to processes that involve it. Axon degeneration has prominent roles in development, upon lesions and in disease. In development, it couples the progressive specification of neurons and circuits to the removal of defined axon branches. Competence might involve transcriptional switches, and local triggering can involve axon guidance molecules and synaptic activity patterns. Lesion-induced Wallerian degeneration is inhibited in the presence of Wld(S) fusion protein in neurons; it involves early local, and later, distal degeneration. It has recently become clear that like in other settings, axon degeneration in disease is a rapid and specific process, which should not be confused with a variety of disease-related pathologies. Elucidating the specific mechanisms that initiate axon degeneration should open up new avenues to investigate principles of circuit assembly and plasticity, to uncover mechanisms of disease progression, and to identify ways of protecting synapses and axons in disease.

  9. Morphometry of Axons in Optic Nerves of Siamese's Twins

    Institute of Scientific and Technical Information of China (English)

    Xinzu Gu; Zhenping Zhang; Qi Lin; Jiongji Liang; Wenyu Lu; Xiulan Ye; A A Sadun

    2002-01-01

    Purpose: To observe the development of optic nerve, we examined four optic nerves from Siameses Twins by absolute counts of axons.Methods: Mean axon diameter, mean axon density, totally axonal population and optic nerve area were noted for each optic nerve. The mean axon diameter and the mean axon density were compared between paraxial (inner sectors)and cortical (outer sectors)areas of the nerves.Results: More myelinated axons were seen in the inner sectors as compared to the outer sectors(average 11 axons/1 000 μm2 in inner sectors and 34 axons/l 000 μm2 in outer sectors( P=0. 036) . The myelinated fibers were also smaller(63 microns) in the outer sectors as compared to the inner sectors(72 microns) ( P = 0. 001 ). The average cross sectors area for the four 40 week stage optical nerves of Siamese Twins was 3.32 × 103 as compared to 1 million axons for 32-week-old normals.Conclusion: Our finding of fewer axonal number and small myelinated fibers in the Siamese Twins suggests hypoplasia. Myelination was more abnormal in the paraxial optic nerve than that in the peripheral sectors, suggesting anomalous development of optic nerve peripherally and delayed developnent centrally. Axonal density is higher in inner sectors than that in outer sectors, suggesting delayed development of the outer nerve sector.

  10. Mecanismos moleculares que confieren resistencia a la apoptosis por TGF-beta en células de Hepatocarcinoma Celular Humano

    OpenAIRE

    Caja Puigsubirà, Laia

    2010-01-01

    En los últimos años nuestro grupo ha estudiado las diferentes vías de señalización inducidas por TGF-β en hepatocitos fetales de rata. A dosis bajas, el TGF-β inhibe el crecimiento, pero a concentraciones más elevadas es capaz de inducir apoptosis (Sanchez et al. 1995; Sanchez et al. 1996). El proceso apoptótico está mediado por un incremento en el contenido intracelular de ROS, dependiente de la síntesis de novo de proteínas, y que correlaciona con una caída en los niveles intracel...

  11. MAPK signaling promotes axonal degeneration by speeding the turnover of the axonal maintenance factor NMNAT2

    Science.gov (United States)

    Walker, Lauren J; Summers, Daniel W; Sasaki, Yo; Brace, EJ; Milbrandt, Jeffrey; DiAntonio, Aaron

    2017-01-01

    Injury-induced (Wallerian) axonal degeneration is regulated via the opposing actions of pro-degenerative factors such as SARM1 and a MAPK signal and pro-survival factors, the most important of which is the NAD+ biosynthetic enzyme NMNAT2 that inhibits activation of the SARM1 pathway. Here we investigate the mechanism by which MAPK signaling facilitates axonal degeneration. We show that MAPK signaling promotes the turnover of the axonal survival factor NMNAT2 in cultured mammalian neurons as well as the Drosophila ortholog dNMNAT in motoneurons. The increased levels of NMNAT2 are required for the axonal protection caused by loss of MAPK signaling. Regulation of NMNAT2 by MAPK signaling does not require SARM1, and so cannot be downstream of SARM1. Hence, pro-degenerative MAPK signaling functions upstream of SARM1 by limiting the levels of the essential axonal survival factor NMNAT2 to promote injury-dependent SARM1 activation. These findings are consistent with a linear molecular pathway for the axonal degeneration program. DOI: http://dx.doi.org/10.7554/eLife.22540.001 PMID:28095293

  12. AxonQuant: A Microfluidic Chamber Culture-Coupled Algorithm That Allows High-Throughput Quantification of Axonal Damage

    Directory of Open Access Journals (Sweden)

    Yang Li

    2014-02-01

    Full Text Available Published methods for imaging and quantitatively analyzing morphological changes in neuronal axons have serious limitations because of their small sample sizes, and their time-consuming and nonobjective nature. Here we present an improved microfluidic chamber design suitable for fast and high-throughput imaging of neuronal axons. We developed the AxonQuant algorithm, which is suitable for automatic processing of axonal imaging data. This microfluidic chamber-coupled algorithm allows calculation of an ‘axonal continuity index' that quantitatively measures axonal health status in a manner independent of neuronal or axonal density. This method allows quantitative analysis of axonal morphology in an automatic and nonbiased manner. Our method will facilitate large-scale high-throughput screening for genes or therapeutic compounds for neurodegenerative diseases involving axonal damage. When combined with imaging technologies utilizing different gene markers, this method will provide new insights into the mechanistic basis for axon degeneration. Our microfluidic chamber culture-coupled AxonQuant algorithm will be widely useful for studying axonal biology and neurodegenerative disorders. © 2014 S. Karger AG, Basel

  13. Motor and dorsal root ganglion axons serve as choice points for the ipsilateral turning of dI3 axons.

    Science.gov (United States)

    Avraham, Oshri; Hadas, Yoav; Vald, Lilach; Hong, Seulgi; Song, Mi-Ryoung; Klar, Avihu

    2010-11-17

    The axons of the spinal intersegmental interneurons are projected longitudinally along various funiculi arrayed along the dorsal-ventral axis of the spinal cord. The roof plate and the floor plate have a profound role in patterning their initial axonal trajectory. However, other positional cues may guide the final architecture of interneuron tracks in the spinal cord. To gain more insight into the organization of specific axonal tracks in the spinal cord, we focused on the trajectory pattern of a genetically defined neuronal population, dI3 neurons, in the chick spinal cord. Exploitation of newly characterized enhancer elements allowed specific labeling of dI3 neurons and axons. dI3 axons are projected ipsilaterally along two longitudinal fascicules at the ventral lateral funiculus (VLF) and the dorsal funiculus (DF). dI3 axons change their trajectory plane from the transverse to the longitudinal axis at two novel checkpoints. The axons that elongate at the DF turn at the dorsal root entry zone, along the axons of the dorsal root ganglion (DRG) neurons, and the axons that elongate at the VLF turn along the axons of motor neurons. Loss and gain of function of the Lim-HD protein Isl1 demonstrate that Isl1 is not required for dI3 cell fate. However, Isl1 is sufficient to impose ipsilateral turning along the motor axons when expressed ectopically in the commissural dI1 neurons. The axonal patterning of dI3 neurons, revealed in this study, highlights the role of established axonal cues-the DRG and motor axons-as intermediate guidepost cues for dI3 axons.

  14. Axon Membrane Skeleton Structure is Optimized for Coordinated Sodium Propagation

    CERN Document Server

    Zhang, Yihao; Li, He; Tzingounis, Anastasios V; Lykotrafitis, George

    2016-01-01

    Axons transmit action potentials with high fidelity and minimal jitter. This unique capability is likely the result of the spatiotemporal arrangement of sodium channels along the axon. Super-resolution microscopy recently revealed that the axon membrane skeleton is structured as a series of actin rings connected by spectrin filaments that are held under entropic tension. Sodium channels also exhibit a periodic distribution pattern, as they bind to ankyrin G, which associates with spectrin. Here, we elucidate the relationship between the axon membrane skeleton structure and the function of the axon. By combining cytoskeletal dynamics and continuum diffusion modeling, we show that spectrin filaments under tension minimize the thermal fluctuations of sodium channels and prevent overlap of neighboring channel trajectories. Importantly, this axon skeletal arrangement allows for a highly reproducible band-like activation of sodium channels leading to coordinated sodium propagation along the axon.

  15. Schwann cells-axon interaction in myelination.

    Science.gov (United States)

    Taveggia, Carla

    2016-08-01

    The remarkable interaction between glial cells and axons is crucial for nervous system development and homeostasis. Alterations in this continuous communication can cause severe pathologies that can compromise the integrity of the nervous system. The most dramatic consequence of this interaction is the generation of the myelin sheath, made by myelinating glial cells: Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system. In this review I will focus on signals coming from axons in the first part and then on those from Schwann cells that promote the formation and the maintenance of peripheral myelin. I will discuss their inter-relationship together with seminal and important advances recently made.

  16. Multifunctional Silk Nerve Guides for Axon Outgrowth

    Science.gov (United States)

    Tupaj, Marie C.

    Peripheral nerve regeneration is a critical issue as 2.8% of trauma patients present with this type of injury, estimating a total of 200,000 nerve repair procedures yearly in the United States. While the peripheral nervous system exhibits slow regeneration, at a rate of 0.5 mm -- 9 mm/day following trauma, this regenerative ability is only possible under certain conditions. Clinical repairs have changed slightly in the last 30 years and standard methods of treatment include suturing damaged nerve ends, allografting, and autografting, with the autograft the gold standard of these approaches. Unfortunately, the use of autografts requires a second surgery and there is a shortage of nerves available for grafting. Allografts are a second option however allografts have lower success rates and are accompanied by the need of immunosuppressant drugs. Recently there has been a focus on developing nerve guides as an "off the shelf" approach. Although some natural and synthetic guidance channels have been approved by the FDA, these nerve guides are unfunctionalized and repair only short gaps, less than 3 cm in length. The goal of this project was to identify strategies for functionalizing peripheral nerve conduits for the outgrowth of neuron axons in vitro . To accomplish this, two strategies (bioelectrical and biophysical) were indentified for increasing axon outgrowth and promoting axon guidance. Bioelectrical strategies exploited electrical stimulation for increasing neurite outgrowth. Biophysical strategies tested a range of surface topographies for axon guidance. Novel methods were developed for integrating electrical and biophysical strategies into silk films in 2D. Finally, a functionalized nerve conduit system was developed that integrated all strategies for the purpose of attaching, elongating, and guiding nervous tissue in vitro. Future directions of this work include silk conduit translation into a rat sciatic nerve model in vivo for the purpose of repairing long

  17. Interspecies variation in axon-myelin relationships.

    Science.gov (United States)

    Fraher, J P; O'Sullivan, A W

    2000-01-01

    The primary objective of this paper was to determine the extent and nature of interspecies differences in axon calibre and myelin sheath thickness and in the various relationships between these. Morphometric analysis of the axon perimeter-myelin sheath thickness relationship was performed on an equivalent nerve fibre population in a mammal, the rat, a bird, the chicken, an amphibian, the frog, a bony fish, the trout, and a cartilaginous fish, the dogfish. The abducent nerve was studied. It is especially suitable for this purpose because its fibres are closely similar in type and in peripheral distribution across the species studied. The relationship differed substantially between species. Differences were present in its setting, as described by the positions of the scatterplots, in the g ratio and in the regression and correlation data relating the parameters. Both parameters were markedly larger in the fish species than in all of the others. In addition, in rat, chicken, frog and trout, where large and small fibre classes could be differentiated clearly, the setting of the relationship between the two parameters was different for the two classes. In the main, variation in each of the parameters was greater between than within species. The larger fibres in the fish species were closely similar in axon perimeter and sheath thickness despite their long evolutionary separation. From this study and from others in the series, it may be concluded that there is no fixed or constant relationship between axon calibre and the thickness of the surrounding myelin sheath. Each nerve tends to have its own particular relationship and this differs between species.

  18. Retinoic acid signaling in axonal regeneration

    Directory of Open Access Journals (Sweden)

    Radhika ePuttagunta

    2012-01-01

    Full Text Available Following an acute central nervous system injury, axonal regeneration and functional recovery are extremely limited. This is due to an extrinsic inhibitory growth environment and the lack of intrinsic growth competence. Retinoic acid (RA signaling, essential in developmental dorsoventral patterning and specification of spinal motor neurons, has been shown through its receptor, the transcription factor RA receptor β2 (RARß2, to induce axonal regeneration following spinal cord injury (SCI. Recently, it has been shown that in dorsal root ganglia neurons, cAMP levels were greatly increased by lentiviral RARβ2 expression and contributed to neurite outgrowth. Moreover, RARβ agonists, in cerebellar granule neurons and in the brain in vivo, induced phosphoinositide 3-kinase dependent phosphorylation of AKT that was involved in RARβ-dependent neurite outgrowth. More recently, RA-RARß pathways were shown to directly transcriptionally repress a member of the inhibitory Nogo receptor complex, Lingo-1, under an axonal growth inhibitory environment in vitro as well as following spinal injury in vivo. This perspective focuses on these newly discovered molecular mechanisms and future directions in the field.

  19. Synaptic Democracy and Vesicular Transport in Axons

    Science.gov (United States)

    Bressloff, Paul C.; Levien, Ethan

    2015-04-01

    Synaptic democracy concerns the general problem of how regions of an axon or dendrite far from the cell body (soma) of a neuron can play an effective role in neuronal function. For example, stimulated synapses far from the soma are unlikely to influence the firing of a neuron unless some sort of active dendritic processing occurs. Analogously, the motor-driven transport of newly synthesized proteins from the soma to presynaptic targets along the axon tends to favor the delivery of resources to proximal synapses. Both of these phenomena reflect fundamental limitations of transport processes based on a localized source. In this Letter, we show that a more democratic distribution of proteins along an axon can be achieved by making the transport process less efficient. This involves two components: bidirectional or "stop-and-go" motor transport (which can be modeled in terms of advection-diffusion), and reversible interactions between motor-cargo complexes and synaptic targets. Both of these features have recently been observed experimentally. Our model suggests that, just as in human societies, there needs to be a balance between "efficiency" and "equality".

  20. MRI of the diffuse axonal injury

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Yang Gu; Woo, Young Hoon; Suh, Soo Jhi [Keimyung University School of Medicine, Daegu (Korea, Republic of)

    1992-01-15

    CT has facilitated early recognition and treatment of focal brain injuries in patients with head trauma. However, CT shows relatively low sensitivity in identifying non hemorrhage contusion and injuries of white matter. MR is known to be superior to CT in detection of white matter injuries, such as diffuse axonal injury. MR imaging in 14 cases of diffuse axonal injury on 2.0T was studied. The corpus callosum, especially the body portion, was the most commonly involved site. The lesions ranged from 5 to 20mm in size with ovoid to elliptical shape. T2WI was the most sensitive pulse sequence in detecting lesions such as white matter degeneration, hemorrhagic and non hemorrhagic contusion. The lesions were nonspecific as high and low signal intensities on T2WI and T1WI respectively. CT showed white matter abnormality in only 1 case of 14 cases. We propose MR imaging as the primary imaging procedure for the detection of diffuse axonal injury because of its multiplanar capabilities and higher sensitivity.

  1. Where does slow axonal transport go?

    Science.gov (United States)

    Terada, Sumio

    2003-12-01

    Axonal transport is the specialized and well-developed intracellular transport system for regulated and/or long-distance transport based on generalized cellular machineries. Among them, slow axonal transport conveys cytoplasmic proteins. The motor molecule, the nature of transporting complex and the transport regulation mechanism for slow transport are still unclarified. There has been a dispute regarding the nature of transporting complex of cytoskeletal proteins, polymer-sliding hypothesis versus subunit-transport theory. Recent data supporting the hypothesis of polymer sliding in cultured neurons only reconfirm the previously reported structure and this inference suffers from the lack of ultrastructural evidence and the direct relevance to the physiological slow transport phenomenon in vivo. Observation of the moving cytoskeletal proteins in vivo using transgenic mice or squid giant axons revealed that subunits do move in a microtubule-dependent manner, strongly indicating the involvement of microtubule-based motor kinesin. If the slow transport rate reflects the intermittent fast transport dependent on kinesin motor, we have to investigate the molecular constituents of the transporting complex in more detail and evaluate why the motor and cargo interaction is so unstable. This kind of weak and fluctuating interaction between various molecular pairs could not be detected by conventional techniques, thus necessitating the establishment of a new experimental system before approaching the molecular regulation problem.

  2. Shh goes multidirectional in axon guidance

    Institute of Scientific and Technical Information of China (English)

    Paola Bovolenta; Luisa Sanchez-Arrones

    2012-01-01

    Shh and Wnts,secreted by the floor and roof plate of the spinal cord,direct longitudinal growth of the axons from the adjacent ventral funiculus and cortico-spinal tract.Whether these midline cues influencethe directionality of axons elongating in more lateral positions of the spinal cord is unexplored.Song and colleagues investigate this possibility and demonstrate that the location of descending raphe-spinal tract in the ventrolateral spinal cord is dictated by the simultaneous repellent activity of Shh gradients in both the anteriorto-posterior (A-P) and medial-tolateral (M-L) axis. The spinal cord is the main pathway for exchange of information between the brain and the rest of the body.Sensory information collected in the body periphery is conveyed to the brain by axonal tracts that ascend along the spinal cord whereas motor information travels from the brain to the periphery in descending tracts.Precise spatial organization of these fiber tracts is thus essential for animal behavior and survival.

  3. Axon-glial relations during regeneration of axons in the adult rat anterior medullary velum.

    Science.gov (United States)

    Berry, M; Hunter, A S; Duncan, A; Lordan, J; Kirvell, S; Tsang, W L; Butt, A M

    1998-12-01

    The anterior medullary velum (AMV) of adult Wistar rats was lesioned in the midsagittal plane, transecting all decussating axons including those of the central projection of the IVth nerve. At selected times up to 200 days after transection, the degenerative and regenerative responses of axons and glia were analyzed using transmission and scanning electron microscopy and immunohistochemistry. In particular, both the capacity of oligodendrocytes to remyelinate regenerated fibers and the stability of the CNS/PNS junctional zone of the IVth nerve rootlet were documented. Transected central AMV axons exhibited four patterns of fiber regeneration in which fibers grew: rostrocaudally in the reactive paralesion neuropil (Group 1); randomly within the AMV (Group 2); into the ipsilateral IVth nerve rootlet, after turning at the lesion edge and growing recurrently through the old degenerated contralateral central trochlear nerve trajectory (Group 3); and ectopically through paralesion tears in the ependyma onto the surface of the IVth ventricle (Group 4). Group 1-3 axons regenerated unperturbed through degenerating central myelin, reactive astrocytes, oligodendrocytes, microglia, and large accumulations of hematogenous macrophages. Only Group 3 axons survived long term in significant numbers, and all became myelinated by oligodendrocytes, ultimately establishing thin sheaths with relatively normal nodal gaps and intersegmental myelin sheath lengths. Schwann cells at the CNS/PNS junction of the IVth nerve rootlet did not invade the CNS, but astrocyte processes grew across the junction into the PNS portion of the IVth nerve. The basal lamina of the junctional glia limitans remained stable throughout the experimental period.

  4. Frecuencia espontánea en inducida de micronúcleos transplacentarios en ratas Sprague Dawley Spontaneous and induced frequency of transplacental micronucleus in Sprague Dawley rats

    Directory of Open Access Journals (Sweden)

    D.F. Arencibia

    2011-06-01

    Full Text Available El presente trabajo tuvo como objetivo determinar la frecuencia espontánea e inducida de micronúcleos transplacentarios en ratas Sprague Dawley, demostrando el efecto clastogénico o aneugénico en el feto a través de la exposición materna y su vinculación con el efecto genotóxico y reproductivo. Se formaron 4 grupos experimentales, 1 control negativo (simulacro, 2 control solvente NaCl (0,9%, 3 ciclofosfamida 50 mg/kg, y 4 bleomicina 30 mg/kg. Todos los grupos se administraron por vía intraperitoneal a los días 14, 15 y 16 de la gestación. A las 48 h posteriores a la última inoculación se procedió a realizar la eutanasia obteniéndose muestras de médula ósea materna y de hígado fetal. Se observó mayor inducción de daño en células hepáticas fetales que en médula ósea materna. Se demostró que la ciclofosfamida es capaz de inducir mayor citotoxicidad y genotoxicidad que la bleomicina en ambos tipos celulares, demostrando el poder clastogénico transplacentario de ambos mutágenos vinculando este ensayo de genotoxicidad a la reproducción. Además estos resultados se podrán utilizar en la evaluación de nuevas drogas con carácter antigenotóxico por vía transplacentaria.The aim of this work were to determine the spontaneous and induced frequency of transplacental micronucleis in Sprague Dawley rats, demonstrating the clastogenic or aneugenic effects in the fetus through the maternal exposure, and their linking with the genotoxic and reproductive effect. Four experimental groups were formed, 1 negative control (mockery, 2 solvent control NaCl (0,9 %, 3 cyclophosphamide to 50 mg/kg, and 4 bleomycin to 30 mg/kg. All the groups were administered the 14, 15 and 16 days of the gestation by intraperitoneal route. 48 h to the last inoculation was preceded to the euthanasia, being obtained the maternal bone marrow and fetal liver samples. Bigger induction of damage was observed in fetal hepatic cells when it was compared with

  5. Dynamics of axon fasciculation in the presence of neuronal turnover

    CERN Document Server

    Chaudhuri, Debasish; Mohanty, P K; Zapotocky, Martin

    2008-01-01

    We formulate and characterize a model aiming to describe the formation of fascicles of axons mediated by contact axon-axon interactions. The growing axons are represented as interacting directed random walks in two spatial dimensions. To mimic axonal turnover in the mammalian olfactory system, the random walkers are injected and removed at specified rates. In the dynamical steady state, the position-dependent distribution of fascicle sizes obeys a scaling law. We identify several distinct time scales that emerge from the dynamics, are sensitive functions of the microscopic parameters of the model, and can exceed the average axonal lifetime by orders of magnitude. We discuss our findings in terms of an analytically tractable, effective model of fascicle dynamics.

  6. Neuropatia experimental por DDT: análise de nervo por microdissecção de fibras

    Directory of Open Access Journals (Sweden)

    Edison Matos Nóvak

    1984-09-01

    Full Text Available Estudou-se o nervo gênito-femural do rato albino submetido a intoxicação crônica por DDT, administrado por 180 dias na dose de 5 mg/kg de peso via oral. Os resultados mostraram proporção anormal de fibras tipo C, sendo sugerido ocorrer degeneração tipo axonal determinada pelo DDT.

  7. Chlorpyrifos-Oxon Disrupts Zebrafish Axonal Growth and Motor Behavior

    OpenAIRE

    Yang, Dongren; Lauridsen, Holly; Buels, Kalmia; Chi, Lai-Har; La Du, Jane; Bruun, Donald A.; Olson, James R.; Tanguay, Robert L.; Lein, Pamela J.

    2011-01-01

    Axonal morphology is a critical determinant of neuronal connectivity, and perturbation of the rate or extent of axonal growth during development has been linked to neurobehavioral deficits in animal models and humans. We previously demonstrated that the organophosphorus pesticide (OP) chlorpyrifos (CPF) inhibits axonal growth in cultured neurons. In this study, we used a zebrafish model to determine whether CPF, its oxon metabolite (CPFO), or the excreted metabolite trichloro-2-pyridinol (TCP...

  8. A unified cell biological perspective on axon-myelin injury

    OpenAIRE

    Simons, Mikael; Misgeld, Thomas; Kerschensteiner, Martin

    2014-01-01

    Demyelination and axon loss are pathological hallmarks of the neuroinflammatory disorder multiple sclerosis (MS). Although we have an increasingly detailed understanding of how immune cells can damage axons and myelin individually, we lack a unified view of how the axon–myelin unit as a whole is affected by immune-mediated attack. In this review, we propose that as a result of the tight cell biological interconnection of axons and myelin, damage to either can spread, which might convert a loc...

  9. Axon-glia interaction and membrane traffic in myelin formation

    OpenAIRE

    2014-01-01

    In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialized glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarization followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is...

  10. Corticostriatal combinatorics: the implications of corticostriatal axonal arborizations.

    Science.gov (United States)

    Zheng, T; Wilson, C J

    2002-02-01

    The complete striatal axonal arborizations of 16 juxtacellularly stained cortical pyramidal cells were analyzed. Corticostriatal neurons were located in the medial agranular or anterior cingulate cortex of rats. All axons were of the extended type and formed synaptic contacts in both the striosomal and matrix compartments as determined by counterstaining for the mu-opiate receptor. Six axonal arborizations were from collaterals of brain stem-projecting cells and the other 10 from bilaterally projecting cells with no brain stem projections. The distribution of synaptic boutons along the axons were convolved with the average dendritic tree volume of spiny projection neurons to obtain an axonal innervation volume and innervation density map for each axon. Innervation volumes varied widely, with single axons occupying between 0.4 and 14.2% of the striatum (average = 4%). The total number of boutons formed by individual axons ranged from 25 to 2,900 (average = 879). Within the innervation volume, the density of innervation was extremely sparse but inhomogeneous. The pattern of innervation resembled matrisomes, as defined by bulk labeling and functional mapping experiments, superimposed on a low background innervation. Using this sample as representative of all corticostriatal axons, the total number of corticostriatal neurons was estimated to be 17 million, about 10 times the number of striatal projection neurons.

  11. Molecular analysis of axon repulsion by the notochord.

    Science.gov (United States)

    Anderson, Christopher N G; Ohta, Kunimasa; Quick, Marie M; Fleming, Angeleen; Keynes, Roger; Tannahill, David

    2003-03-01

    During development of the amniote peripheral nervous system, the initial trajectory of primary sensory axons is determined largely by the action of axon repellents. We have shown previously that tissues flanking dorsal root ganglia, the notochord lying medially and the dermamyotomes lying laterally, are sources of secreted molecules that prevent axons from entering inappropriate territories. Although there is evidence suggesting that SEMA3A contributes to the repellent activity of the dermamyotome, the nature of the activity secreted by the notochord remains undetermined. We have employed an expression cloning strategy to search for axon repellents secreted by the notochord, and have identified SEMA3A as a candidate repellent. Moreover, using a spectrum of different axon populations to assay the notochord activity, together with neuropilin/Fc receptor reagents to block semaphorin activity in collagen gel assays, we show that SEMA3A probably contributes to notochord-mediated repulsion. Sympathetic axons that normally avoid the midline in vivo are also repelled, in part, by a semaphorin-based notochord activity. Although our results implicate semaphorin signalling in mediating repulsion by the notochord, repulsion of early dorsal root ganglion axons is only partially blocked when using neuropilin/Fc reagents. Moreover, retinal axons, which are insensitive to SEMA3A, are also repelled by the notochord. We conclude that multiple factors act in concert to guide axons in this system, and that further notochord repellents remain to be identified.

  12. Differences in excitability properties of FDI and ADM motor axons.

    Science.gov (United States)

    Bae, Jong Seok; Sawai, Setsu; Misawa, Sonoko; Kanai, Kazuaki; Isose, Sagiri; Kuwabara, Satoshi

    2009-03-01

    The first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles are innervated by the same ulnar nerve, but studies have shown that the former is much more severely affected in amyotrophic lateral sclerosis. In this study, threshold tracking was used to investigate whether membrane properties differ between FDI and ADM motor axons. In 12 normal subjects, compound muscle action potentials were recorded from FDI and ADM after ulnar nerve stimulation at the wrist. The strength-duration time constant was significantly longer in the FDI axons than in the ADM axons, and latent addition studies showed greater threshold changes at the conditioning-test stimulus of 0.2 ms in FDI than in ADM axons. These findings suggest that nodal persistent sodium conductances are more prominent in FDI axons than in ADM axons, and therefore excitability is physiologically higher in FDI axons. Even in the same nerve at the same sites, membrane properties of FDI and ADM motor axons differ significantly, and thus their axonal/neuronal responses to disease may also differ.

  13. Fast axonal transport in early experimental disc edema.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1980-02-01

    Previous work has documented impairment of slow axonal transport in papilledema, but the abnormalities in rapid transport were less certain. Therefore fast axonal transport was studied in 19 primate eyes subjected to ocular hypotony for 6 to 72 hr following surgical fistulization of the anterior chamber. Mild, irregular alterations in fast axonal transport were detected only after nerve head swelling was apparent. These changes in fast transport mechanisms in cases of nerve head edema occur after, and may be secondary to, impaired slow axoplasmic flow and the resultant axonal swelling. Furthermore, since prolonged complete interruption of axonal transport is theoretically inconsistent with the continued normal neuron function characteristic of papilledema and, moreover, since previous data shows a "slowdown" rather than complete blockade of axonal transport in papilledema, it is likely that in eyes with papilledema there does not exist a complete flock of axonal transport. Therefore we hypothesize that the swelling results when slow axoplasmic flow is locally slowed down but not totally stopped, with the axon distention producing secondary mild, irregular changes in fast axonal transport.

  14. Axonal autophagy during regeneration of the rat sciatic nerve

    Institute of Scientific and Technical Information of China (English)

    Kangrong Lu; Zhongxian Piao; Zhenxi Liu; Weiwang Gu; Wanshan Wang; Nngjie Piao

    2008-01-01

    BACKGROUND: The removal of degenerated axonal debris during Wallerian degeneration is very important for nerve regeneration. However, the mechanism by which debris is removed is not been completely understood. Considerable controversy remains as to the clearance pathway and cells that are involved. OBJECTIVE: To investigate axonal autophagy during removal of degenerated axonal debris by transecting the sciatic nerve in a rat Wallerian degeneration model.DESIGN, TIME AND SETTING: Experimental neuropathological analysis. The experiment was conducted at the Laboratory Animal Service Center of the Southern Medical University between January and June 2005. MATERIALS: Fifty-four adult, Wistar rats of either sex, weighing 180-250 g, were obtained from the Laboratory Animal Service Center of the Southern Medical University. Animals were randomly divided into nine groups of six rats. METHODS: Wallerian degeneration was induced by transecting the rat sciatic nerve, and tissue samples from the distal stump were obtained 0.2, 0.4, 1, 2, 3, 4, 7, 10, and 15 days post-transection. Ultrathin sections were prepared for electron microscopy to study ultrastructure and enzyme cytochemistry staining. MAIN OUTCOME MEASURES: Ultrastructure (axon body, autophagic body, and cystoskeleton) of axons and myelin sheaths observed with electron microscopy; acidic phosphatase activity detected by Gomori staining using electron microscopy. RESULTS: The major changes of degenerating axons after transection were axoplasm swelling and separation of axons from their myelin sheath between five hours and two days post-transection. At four days post-transection, the axoplasm condensed and axons were completely separated from the myelin sheath, forming dissociative axon bodies. Vacuoles of different sizes formed in axons during the early phase after lesion. Larger dissociative axon bodies were formed when the axons were completely separated from the myelin sheath during a late phase. The axolemma

  15. Crossing the Border: Molecular Control of Motor Axon Exit

    Directory of Open Access Journals (Sweden)

    Arlene Bravo-Ambrosio

    2011-11-01

    Full Text Available Living organisms heavily rely on the function of motor circuits for their survival and for adapting to ever-changing environments. Unique among central nervous system (CNS neurons, motor neurons (MNs project their axons out of the CNS. Once in the periphery, motor axons navigate along highly stereotyped trajectories, often at considerable distances from their cell bodies, to innervate appropriate muscle targets. A key decision made by pathfinding motor axons is whether to exit the CNS through dorsal or ventral motor exit points (MEPs. In contrast to the major advances made in understanding the mechanisms that regulate the specification of MN subtypes and the innervation of limb muscles, remarkably little is known about how MN axons project out of the CNS. Nevertheless, a limited number of studies, mainly in Drosophila, have identified transcription factors, and in some cases candidate downstream effector molecules, that are required for motor axons to exit the spinal cord. Notably, specialized neural crest cell derivatives, referred to as Boundary Cap (BC cells, pre-figure and demarcate MEPs in vertebrates. Surprisingly, however, BC cells are not required for MN axon exit, but rather restrict MN cell bodies from ectopically migrating along their axons out of the CNS. Here, we describe the small set of studies that have addressed motor axon exit in Drosophila and vertebrates, and discuss our fragmentary knowledge of the mechanisms, which guide motor axons out of the CNS.

  16. A unified cell biological perspective on axon-myelin injury.

    Science.gov (United States)

    Simons, Mikael; Misgeld, Thomas; Kerschensteiner, Martin

    2014-08-04

    Demyelination and axon loss are pathological hallmarks of the neuroinflammatory disorder multiple sclerosis (MS). Although we have an increasingly detailed understanding of how immune cells can damage axons and myelin individually, we lack a unified view of how the axon-myelin unit as a whole is affected by immune-mediated attack. In this review, we propose that as a result of the tight cell biological interconnection of axons and myelin, damage to either can spread, which might convert a local inflammatory disease process early in MS into the global progressive disorder seen during later stages. This mode of spreading could also apply to other neurological disorders.

  17. Present status of studies on diffuse axonal injury

    Institute of Scientific and Technical Information of China (English)

    Jie Ma; Chonggong Zhang; Yi Li

    2006-01-01

    OBJECTIVE: To explain the present status of study on diffuse axonal injury,investigate its pathogenesis and pathophysiological changes ,and suggest principles for the diagnosis and treatment.DATA SOURCES: Articles about diffuse axonal injury published in English from January 1994 to October 2006 were searched in Pubmed database using the keywords of "diffuse axonal injury,pathogenesis,therapy".STUDY SELECTION: The collected articles were primarily screened to select those associated with diffuse axonal injury,the obviously irrelated articles were excluded,and the rest ones were retrieved manually,and the full-texes were searched.DATA EXTRACTION: Totally 98 articles were collected,41 of them were involved.and the other 57 were excluded.DATA SYNTHESIS: Diffuse axonal injury is mainly caused by acceleratory or deceleratory injury,and its pathophysiological change is a progressive duration,local axonal injury finally develops to axonal breakage,mainly includes inactivation of natrium channel,intracellular Ca2+ overloading,activation of calcium protease,caspase etc.,and mitochondrial injury.At present,there is still lack of effective therapeutic methods for diffuse axonal injury,so we should actively explore more effective methods to relieve the pain of patients and improve their prognosis.CONCLUSION: At present,diffuse axonal injury has not attracted enough attentions in China,the mechanisms for its diagnosis and attack are still unclear,and the treatments are mainly aiming at the symptoms.

  18. Dopaminergic axon guidance: which makes what?

    Directory of Open Access Journals (Sweden)

    Laetitia ePrestoz

    2012-07-01

    Full Text Available Mesotelencephalic pathways in the adult central nervous system have been studied in great detail because of their implication in major physiological functions as well as in psychiatric, neurological and neurodegenerative diseases. However, the ontogeny of these pathways and the molecular mechanisms that guide dopaminergic axons during embryogenesis have been only recently studied. This line of research is of crucial interest for the repair of lesioned circuits in adulthood following neurodegenerative diseases or common traumatic injuries. For instance, in the adult, the anatomic and functional repair of the nigrostriatal pathway following dopaminergic embryonic neuron transplantation suggests that specific guidance cues exist which govern embryonic fibers outgrowth, and suggests that axons from transplanted embryonic cells are able to respond to theses cues, which then guide them to their final targets. In this review, we first synthesize the work that has been performed in the last few years on developing mesotelencephalic pathways, and summarize the current knowledge on the identity of cellular and molecular signals thought to be involved in establishing mesotelencephalic dopaminergic neuronal connectivity during embryogenesis in the central nervous system of rodents. Then, we review the modulation of expression of these molecular signals in the lesioned adult brain and discuss their potential role in remodeling the mesotelencephalic dopaminergic circuitry, with a particular focus on Parkinson’s disease. Identifying guidance molecules involved in the connection of grafted cells may be useful for cellular therapy in Parkinsonian patients, as these molecules may help direct axons from grafted cells along the long distance they have to travel from the substantia nigra to the striatum.

  19. Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy

    DEFF Research Database (Denmark)

    Fenrich, Keith K; Skelton, Nicole; MacDermid, Victoria E

    2007-01-01

    at 4-5 weeks post injury. The somata of axotomized CINs were identified by the presence of immunoreactivity for the axonal growth-associated protein-43 (GAP-43). Nearly half of the CINs had de novo axons that emerged from distal dendrites. These axons lacked immunoreactivity for the dendritic protein......Following proximal axotomy, several types of neurons sprout de novo axons from distal dendrites. These processes may represent a means of forming new circuits following spinal cord injury. However, it is not know whether mammalian spinal interneurons, axotomized as a result of a spinal cord injury......, develop de novo axons. Our goal was to determine whether spinal commissural interneurons (CINs), axotomized by 3-4-mm midsagittal transection at C3, form de novo axons from distal dendrites. All experiments were performed on adult cats. CINs in C3 were stained with extracellular injections of Neurobiotin...

  20. El dipéptido de glutamina administrado por vía oral promueve la recuperación de glucemia aguda en ratas sometidas a hipoglucemia por insulina durante largo tiempo

    OpenAIRE

    2008-01-01

    Fue comparado el efecto agudo de la administración oral (100 mg/kg) del dipéptido de glutamina (L-alanil-L-glutamina, AGP), L-alanina (ALA) y L-glutamina (GLN) en la recuperación de la glucemia (RG) en los casos de hipoglucemia inducida por insulina (IIH) durante largo tiempo. Se comparó el comportamiento de ratas en ayuno de 24 h que recibieron insulina regular por vía intraperitoneal (1,0 U/kg) y luego de 165 min AGP, ALA, GLN o solución salina por vía oral. La glucemia fue evaluada a los 1...

  1. IMP2 axonal localization, RNA interactome, and function in the development of axon trajectories

    DEFF Research Database (Denmark)

    Preitner, Nicolas; Quan, Jie; Li, Xinmin

    2016-01-01

    RNA-based regulatory mechanisms play important roles in the development and plasticity of neural circuits and neurological disease. Developing axons provide a model well suited to the study of RNA-based regulation, and contain specific subsets of mRNAs that are locally translated and have roles i...

  2. White-matter astrocytes, axonal energy metabolism, and axonal degeneration in multiple sclerosis

    NARCIS (Netherlands)

    Cambron, Melissa; D'haeseleer, Miguel; Laureys, Guy; Clinckers, Ralph; Debruyne, Jan; De Keyser, Jacques

    2012-01-01

    In patients with multiple sclerosis (MS), a diffuse axonal degeneration occurring throughout the white matter of the central nervous system causes progressive neurologic disability. The underlying mechanism is unclear. This review describes a number of pathways by which dysfunctional astrocytes in M

  3. Effect of rofecoxib on colon chemical carcinogenesis at colonic anastomotic area in the rat Influencia del rofecoxib en la carcinogénesis cólica perianastomótica inducida en ratas

    Directory of Open Access Journals (Sweden)

    J. F. Noguera Aguilar

    2005-06-01

    durante 18 semanas y se analizaron los tumores cólicos inducidos en la semana 20 del postoperatorio. El principal parámetro evaluado fue el porcentaje de tejido cólico neoplásico, que relaciona la superficie tumoral con la superficie del colon. Resultados: el rofecoxib a dosis de 0,0058 ppm redujo significativamente la carcinogénesis cólica inducida en ratas, tanto a nivel perianastomótico como en el resto del colon (p < 0,01. A nivel extraanastomótico, el rofecoxib a dosis de 2,5 mg/kg fue significativamente superior en su efecto inhibidor al rofecoxib a dosis de 1,2 mg/kg o 0,0027 ppm (p < 0,005. Conclusiones: el rofecoxib produce una disminución en la carcinogénesis cólica farmacológicamente inducida en ratas. Este efecto se mantiene en el área perianastomótica, por lo que puede ser interesante investigar su implicación en el cáncer colorrectal intervenido con riesgo de recidiva locorregional.

  4. AxonPacking: An Open-Source Software to Simulate Arrangements of Axons in White Matter.

    Science.gov (United States)

    Mingasson, Tom; Duval, Tanguy; Stikov, Nikola; Cohen-Adad, Julien

    2017-01-01

    HIGHLIGHTS AxonPacking: Open-source software for simulating white matter microstructure.Validation on a theoretical disk packing problem.Reproducible and stable for various densities and diameter distributions.Can be used to study interplay between myelin/fiber density and restricted fraction. Quantitative Magnetic Resonance Imaging (MRI) can provide parameters that describe white matter microstructure, such as the fiber volume fraction (FVF), the myelin volume fraction (MVF) or the axon volume fraction (AVF) via the fraction of restricted water (fr). While already being used for clinical application, the complex interplay between these parameters requires thorough validation via simulations. These simulations required a realistic, controlled and adaptable model of the white matter axons with the surrounding myelin sheath. While there already exist useful algorithms to perform this task, none of them combine optimisation of axon packing, presence of myelin sheath and availability as free and open source software. Here, we introduce a novel disk packing algorithm that addresses these issues. The performance of the algorithm is tested in term of reproducibility over 50 runs, resulting density, and stability over iterations. This tool was then used to derive multiple values of FVF and to study the impact of this parameter on fr and MVF in light of the known microstructure based on histology sample. The standard deviation of the axon density over runs was lower than 10(-3) and the expected hexagonal packing for monodisperse disks was obtained with a density close to the optimal density (obtained: 0.892, theoretical: 0.907). Using an FVF ranging within [0.58, 0.82] and a mean inter-axon gap ranging within [0.1, 1.1] μm, MVF ranged within [0.32, 0.44] and fr ranged within [0.39, 0.71], which is consistent with the histology. The proposed algorithm is implemented in the open-source software AxonPacking (https://github.com/neuropoly/axonpacking) and can be useful for

  5. Les activités de gestion d’alerte épidémiologique : les transformations induites par l’utilisation d’un système de surveillance en temps réel Alert Management Activity: Cognitive and team activity modifications due to the use of an early warning system Las actividades de gestión de alerta epidemiológica : las transformaciones inducidas por la utilización de un sistema de vigilancia en tiempo real

    Directory of Open Access Journals (Sweden)

    Charlotte Gaudin

    2012-05-01

    dinámico puesto que las epidemias evolucionan y se propagan rápidamente si ninguna acción es emprendida para controlarlas. Más precisamente dos tipos de situaciones son analizadas : (1 la actividad tradicional de gestión de alerta y (2 esta misma actividad cuando es asistida por un sistema informático, en el caso el sistema ASTER (o Alerta y Supervisión en Tiempo Real. Luego, los resultados obtenidos son discutidos a nivel cognitivo y a nivel de las actividades colectivas consecutivamente a la introducción y a la utilización de un sistema técnico.

  6. Estudio de la cinética de precipitación inducida mediante la determinación de los diagramas Precipitación-Tiempo-Temperatura (PTT en aceros microaleados

    Directory of Open Access Journals (Sweden)

    Medina, S. F.

    1995-10-01

    Full Text Available A method developed in the CENIM is described which allows to study the induced precipitation kinetics by the deformation in microalloyed steels. By means of torsion tests the statically recristallized fraction of three microalloyed steels with Nb, V or Ti, has been determined to different temperatures and deformations. When the precipitation begins, the recrystallized fraction is separated of the Avrami's equation and this allows to know the instant the precipitation begins (Ps and the instant the precipitation finishes (Pf. Thereby can be traced the Precipitation-Time-Temperature (PTT diagrams which graphically show the precipitation kinetics.

    Se describe un método desarrollado en el CENIM que permite estudiar la cinética de la precipitación inducida por la deformación en aceros microaleados. Mediante ensayos de torsión, se ha determinado la fracción recristalizada estáticamente de tres aceros microaleados con niobio, vanadio y titanio, respectivamente, a diferentes temperaturas y deformaciones. Cuando la precipitación comienza, la fracción recristalizada se desvía de la ecuación de Avrami y esto permite conocer el instante en el que la precipitación comienza (Ps y el instante en que termina (Pf. De este modo, se pueden trazar las curvas de Precipitación-Tiempo-Temperatura (PTT que muestran gráficamente la cinética de precipitación.

  7. Differential extraction of axonally transported proteoglycans

    Energy Technology Data Exchange (ETDEWEB)

    Elam, J.S. (Florida State Univ., Tallahassee (USA))

    1990-10-01

    Axonally transported proteoglycans were differentially solubilized by a sequence of extractions designed to infer their relationship to nerve terminal membranes. Groups of goldfish were injected unilaterally with 35SO4 and contralateral optic tecta containing axonally transported molecules were removed 16 h later. Tecta were homogenized in isotonic buffer and centrifuged at 100,000 g for 60 min to create a total supernatant fraction. Subsequent homogenizations followed by recentrifugation were with hypotonic buffer (lysis extract), 1 M NaCl, Triton X-100 or alternatively Triton-1 M NaCl. Populations of proteoglycans in each extract were isolated on DEAE ion exchange columns and evaluated for content of glycosaminoglycans (GAGs). Results show the distribution of transported proteoglycans to be 26.3% total soluble, 13.7% lysis extract, 13.8% NaCl extract, 12.2% Triton extract, and 46.2% Triton-NaCl extract. Proteoglycans from all fractions contained heparan sulfate as the predominant GAG, with lesser amounts of chondroitin (4 or 6) sulfate. The possible localizations of transported proteoglycans suggested by the extraction results are discussed.

  8. Papel de las especies reactivas del oxígeno en el daño al miocardio inducido por isquemia/reperfusión

    OpenAIRE

    Livan Delgado-Roche; Gregorio Martínez-Sánchez

    2010-01-01

    RESUMENLas enfermedades de las arterias coronarias constituyen una de las principales causas demuerte en los países occidentales. Una de las manifestaciones patológicas en este tipo deenfermedades es el daño al miocardio, el cual puede ser una consecuencia de los episodios deisquemia/reperfusión que tienen lugar. A pesar de la complejidad de los mecanismos responsablesde la afectación al miocardio inducida por isquemia/reperfusión, se han podido identificaralgunos factores que inciden notable...

  9. Receptores de la prostaglandina E2 implicados en los trastornos motores digestivos y la fiebre inducidos por endotoxinas en la oveja: Papel de los macrófagos

    OpenAIRE

    Gimeno Soriano, Aurora; Plaza Carrión, Miguel Ángel; Castro López, Marta

    2014-01-01

    El objetivo general de este trabajo ha sido el estudio de los mecanismos fisiopatológicos implicados en la fiebre y en las alteraciones motoras digestivas inducidas por una endotoxina bacteriana: el lipopolisacárido (LPS) de Escherichia coli en la oveja. Se ha estudiado la participación de los receptores de la prostaglandina (PG) E2 (EP1, EP2, EP3 y EP4), los tipos celulares que están implicados en la síntesis y liberación de PGs en el hipotálamo y bulbo raquídeo y la posible participación de...

  10. Nefrotoxicidad por contrastes yodados en estudios de tomografía computarizada a pacientes ambulatorios diabéticos en tratamiento con metformina

    OpenAIRE

    H. Gómez Herrero; C. De Arriba Villamor; M. Buldain Parra; M. Arraiza Sarasa

    2013-01-01

    Fundamento. Determinar la incidencia de nefropatía inducida por contraste (NIC) en un grupo de pacientes diabéticos en tratamiento con metformina a los que se realiza un estudio de tomografía computarizada (TC) con contraste yodado intravenoso (civ) Material y Métodos. Estudio prospectivo de pacientes diabéticos incluidos en el protocolo para la prevención de la acidosis láctica a los que se hace seguimiento clínico y analítico tras la realización de una TC con civ. Resultados. Se recogieron ...

  11. EFECTO DE Tropaeolum tuberosum FRENTE A LA HIPERPLASIA PROSTÁTICA BENIGNA INDUCIDA EN RATAS HOLTZMAN

    Directory of Open Access Journals (Sweden)

    Gioliana Aire-Artezano

    2013-01-01

    Full Text Available Objetivo: Evaluar el efecto de Tropaeolum tuberosum(mashua frente a la Hiperplasia Prostática Benigna (HPB y compararlo con finasterida. Métodos: Estudio experimental completo. Se emplearon 30 ratas Holtzman macho de 12 semanas de edad, aleatorizadas y divididas en seis gru- pos: grupo blanco; grupo testosterona; grupo finasterida (0.33mg/kg/rata; y tres grupos dosis, dosis 1 (300mg/kg/rata, dosis 2 (500mg/kg/rata y dosis 3 (800mg/kg/rata tratados con Tropaeolum tuberosum. Se realizó una medición basal del volumen prostático mediante una ecografía transabdominal. La inducción de HPB se realizó con enantato de testosterona (0,083mg/Kg/rata en los grupos dosis, finasterida y testosterona, el día uno y siete. Paralelamente, se administró liofilizado de Tropaeolum tuberosum y finasterida durante 21 días. Para el diagnóstico, se realiza- ron estudios por imágenes, anatomopatológicos e histopatológicos. Resultados: El estudio por imágenes, en relación al incremento del volumen prostático,no arrojó diferencia significativa entre dosis 2 y finasterida; mientras que en relación con la ecogenicidad, dosis 3 presentó similitud cualitativa al finasterida. En el estudio anatomopatológico, no hubo diferencia significativa entre el grupo dosis 3 y el grupo finasterida. Histo- patológicamente, dosis 3 se asemejó cuantitativamente al finasterida. Conclusiones: Se evidenció disminución de la HPB histológicamente y en el estudio por imágenes; sin embargo, ninguna de las dosis mostró efecto superior al finasterida.

  12. Procesos de corrosión debidos a corrientes alternas inducidas (60 Hz

    Directory of Open Access Journals (Sweden)

    Vera, E.

    1996-10-01

    Full Text Available The phenomenon by which a sinusoidal a.c. signal damages a steel in contact with an aggressive electrolite was determined. Thus, a series of electrochemical tests was carried out, when a signal of the previously mentioned characteristics is present in the metal-electrolite interphase, both with cathodic protection and without it. The results allowed to postulate an empirical relationship that determines the corrosive process kinetics exerted by the action of an alternating signal. The phenomenon by which the AC signal generates a corrosion state over a probe was determined from the physical point of view.

    Se determinó el fenómeno por el que una señal de c.a. de tipo sinusoidal genera fenómenos de corrosión en un acero en contacto con un electrólito agresivo. Para ello, se realizaron pruebas electroquímicas cuando una señal de las anteriores características está presente en la interfase metal-electrólito, con y sin protección catódica. Los resultados permitieron postular una relación empírica que determina la cinética del proceso corrosivo ejercido por la acción de la señal alterna. Se determinó, desde un punto de vista físico, el fenómeno por el cual la señal de c.a. genera un estado de corrosión sobre la probeta.

  13. Neuronal Logistics : Axonal Transport in Development and Disease

    NARCIS (Netherlands)

    R. van den Berg (Robert)

    2016-01-01

    markdownabstractBrain cells are uniquely shaped among the many cell types of the body. While most cells are more or less rounded or square-shaped, neurons grow one or more long axons that can reach lengths of a meter or more. To keep these axons alive and functional, neurons are dependent on an intr

  14. Molecular Determinants Fundamental to Axon Regeneration after SCI

    Science.gov (United States)

    2014-09-01

    TITLE: Molecular Determinants Fundamental to Axon Regeneration after SCI PRINCIPAL INVESTIGATOR: Jeffrey Alan Plunkett, Ph.D. Martin...TYPE FINAL 3. DATES COVERED (From - To) 1 Sept 2011 - 1 Sept 2014 4. TITLE AND SUBTITLE Molecular Determinants Fundamental to Axon Regeneration...available that restore motor impairments resulting fromspinal cord injury (SCI). Soldiers with SCI are permanently paralyzed and in needof lifelong care

  15. Molecular Determinants Fundamental to Axon Regeneration after SCI

    Science.gov (United States)

    2012-06-01

    currently employed to investigate the evolution of the scar and the time course of axon regeneration after spinal cord injury. The data from these...Medicine, Pittsburgh, PA. It has been established in amphibians and fish that neurons can successfully regenerate their axons in the damaged central

  16. Spontaneous axonal regeneration in rodent spinal cord after ischemic injury

    DEFF Research Database (Denmark)

    von Euler, Mia; Janson, A M; Larsen, Jytte Overgaard;

    2002-01-01

    Here we present evidence for spontaneous and long-lasting regeneration of CNS axons after spinal cord lesions in adult rats. The length of 200 kD neurofilament (NF)-immunolabeled axons was estimated after photochemically induced ischemic spinal cord lesions using a stereological tool. The total l...

  17. Inhibiting poly(ADP-ribosylation) improves axon regeneration

    Science.gov (United States)

    Byrne, Alexandra B; McWhirter, Rebecca D; Sekine, Yuichi; Strittmatter, Stephen M; Miller, David M; Hammarlund, Marc

    2016-01-01

    The ability of a neuron to regenerate its axon after injury depends in part on its intrinsic regenerative potential. Here, we identify novel intrinsic regulators of axon regeneration: poly(ADP-ribose) glycohodrolases (PARGs) and poly(ADP-ribose) polymerases (PARPs). PARGs, which remove poly(ADP-ribose) from proteins, act in injured C. elegans GABA motor neurons to enhance axon regeneration. PARG expression is regulated by DLK signaling, and PARGs mediate DLK function in enhancing axon regeneration. Conversely, PARPs, which add poly(ADP-ribose) to proteins, inhibit axon regeneration of both C. elegans GABA neurons and mammalian cortical neurons. Furthermore, chemical PARP inhibitors improve axon regeneration when administered after injury. Our results indicate that regulation of poly(ADP-ribose) levels is a critical function of the DLK regeneration pathway, that poly-(ADP ribosylation) inhibits axon regeneration across species, and that chemical inhibition of PARPs can elicit axon regeneration. DOI: http://dx.doi.org/10.7554/eLife.12734.001

  18. Axon guidance of rat cortical neurons by microcontact printed gradients.

    Science.gov (United States)

    Fricke, Rita; Zentis, Peter D; Rajappa, Lionel T; Hofmann, Boris; Banzet, Marko; Offenhäusser, Andreas; Meffert, Simone H

    2011-03-01

    Substrate-bound gradients expressed in numerous spatio-temporal patterns play a crucial role during the development of complex neural circuits. A deeper understanding of the axon guidance mechanism is provided by studying the effect of a defined substrate-bound cue on a confined neural network. In this study, we constructed a discontinuous substrate-bound gradient to control neuronal cell position, the path of neurite growth, and axon directionality. A variety of gradient patterns, with slight changes in slope, width, and length were designed and fabricated by microcontact printing using laminin/poly-l-lysine (PLL) or PLL alone. The gradients were tested for neurite growth and their impact on axon guidance of embryonic rat cortical neurons. The neurite length was determined and the axon was evaluated by Tau-1 immunostaining. We found that the microgradients of laminin/PLL and PLL directed neurons' adhesion, differentially controlled the neurite growth, and guided up to 84% of the axons. The effect of the protein micropattern on axon guidance and neurite growth depended on the protein and geometric parameters used. Our approach proved to be very successful in guiding axons of single multipolar neurons with very high efficiency. It could thereby be useful to engineer defined neural networks for analyzing signal processing of functional circuits, as well as to unravel fundamental questions of the axon guidance mechanism.

  19. Actividad antioxidante y gastroprotectora del extracto hidroalcohólico de hojas de Heliotropum arborescens L, en úlceras inducidas con etanol en estómago de ratas

    OpenAIRE

    Palomino, Miriam; Facultad de Medicina UNMSM; Huamán, Oscar; Facultad de Medicina UNMSM; Béjar, Elsa; Facultad de Medicina UNMSM; Palomino, Christian; Facultad de Medicina UNMSM; Najarro, Justina; Facultad de Medicina UNMSM

    2013-01-01

    Objetivos: Evaluar la actividad antioxidante y protectora del extracto hidroalcohólico de Heliotropium arborescens L ‘cayaraja’ sobre la mucosa gástrica en úlceras inducidas en ratas. Evaluar el efecto antioxidante. Evaluar el grado de protección del extracto en estómago de ratas Diseño: Descriptivo transversal Institución: Facultad de Medicina UNMSM. material biológico: 48 ratas machos y 30 ratones. Intervenciones: Para evaluar el efecto protector se administró fármacos y extracto a 6 grupos...

  20. Increased Human Wildtype Tau Attenuates Axonal Transport Deficits Caused by Loss of APP in Mouse Models

    OpenAIRE

    Smith, Karen D.B.; Erica Peethumnongsin; Han Lin; Hui Zheng; Pautler, Robia G.

    2010-01-01

    Amyloid precursor protein (APP) is implicated in axonal elongation, synaptic plasticity, and axonal transport. However, the role of APP on axonal transport in conjunction with the microtubule associated protein tau continues to be debated. Here we measured in vivo axonal transport in APP knockout mice with Manganese Enhanced MRI (MEMRI) to determine whether APP is necessary for maintaining normal axonal transport. We also tested how overexpression and mutations of tau affect axonal transport ...

  1. SnoN facilitates axonal regeneration after spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Jiun L Do

    Full Text Available Adult CNS neurons exhibit a reduced capacity for growth compared to developing neurons, due in part to downregulation of growth-associated genes as development is completed. We tested the hypothesis that SnoN, an embryonically regulated transcription factor that specifies growth of the axonal compartment, can enhance growth in injured adult neurons. In vitro, SnoN overexpression in dissociated adult DRG neuronal cultures significantly enhanced neurite outgrowth. Moreover, TGF-β1, a negative regulator of SnoN, inhibited neurite outgrowth, and SnoN over-expression overcame this inhibition. We then examined whether SnoN influenced axonal regeneration in vivo: indeed, expression of a mutant form of SnoN resistant to degradation significantly enhanced axonal regeneration following cervical spinal cord injury, despite peri-lesional upregulation of TGF-β1. Thus, a developmental mechanism that specifies extension of the axonal compartment also promotes axonal regeneration after adult CNS injury.

  2. Internodal function in normal and regenerated mammalian axons

    DEFF Research Database (Denmark)

    Moldovan, M; Krarup, C

    2007-01-01

    AIM: Following Wallerian degeneration, peripheral myelinated axons have the ability to regenerate and, given a proper pathway, establish functional connections with targets. In spite of this capacity, the clinical outcome of nerve regeneration remains unsatisfactory. Early studies have found...... that regenerated internodes remain persistently short though this abnormality did not seem to influence recovery in conduction. It remains unclear to which extent abnormalities in axonal function itself may contribute to the poor outcome of nerve regeneration. METHODS: We review experimental evidence indicating...... that internodes play an active role in axonal function. RESULTS: By investigating internodal contribution to axonal excitability we have found evidence that axonal function may be permanently compromised in regenerated nerves. Furthermore, we illustrate that internodal function is also abnormal in regenerated...

  3. Signaling mechanisms in cortical axon growth, guidance and branching

    Directory of Open Access Journals (Sweden)

    Katherine eKalil

    2011-09-01

    Full Text Available Precise wiring of cortical circuits during development depends upon axon extension, guidance and branching to appropriate targets. Motile growth cones at axon tips navigate through the nervous system by responding to molecular cues, which modulate signaling pathways within axonal growth cones. Intracellular calcium signaling has emerged as a major transducer of guidance cues but exactly how calcium signaling pathways modify the actin and microtubule cytoskeleton to evoke growth cone behaviors and axon branching is still mysterious. Axons must often pause in their outgrowth while their branches extend into targets. Some evidence suggests a competition between growth of axons and branches but the mechanisms are poorly understood. Since it is difficult to study growing axons deep within the mammalian brain, much of what we know about signaling pathways and cytoskeletal dynamics has come from studies of axonal growth cones, in many cases from non-mammalian species, growing in tissue culture. Consequently it is not well understood how guidance cues relevant to mammalian neural development in vivo signal to the growth cone cytoskeleton during axon outgrowth and guidance. In this review we describe our recent work in dissociated cultures of developing rodent sensorimotor cortex in the context of the current literature on molecular guidance cues, calcium signaling pathways and cytoskeletal dynamics that regulate growth cone behaviors. A major challenge is to relate findings in tissue culture to mechanisms of cortical development in vivo. Toward this goal, we describe our recent work in cortical slices, which preserve the complex cellular and molecular environment of the mammalian brain but allow direct visualization of growth cone behaviors and calcium signaling. Findings from this work suggest that mechanisms regulating axon growth and guidance in dissociated culture neurons also underlie development of cortical connectivity in vivo.

  4. por valores

    Directory of Open Access Journals (Sweden)

    Jazmín Díaz-Barrios

    2005-01-01

    Full Text Available La era actual se caracteriza por una búsqueda de la identidad del hombre, donde el pivote del cambio organizacional es el individuo; cambiar en este entorno depende, en gran medida, de los valores que imperen en la cultura de la organización. Este trabajo documental intenta identificar aquellos valores, condición sine-qua-non, para el logro de los objetivos de cambio y analizarlos a fin de determinar sus indicadores, con el objeto de presentar una herramienta a las organizaciones que les facilite adaptarse a los nuevos tiempos. Se encontró que los valores: Delegación, Comunicación, Colaboración, Participación y Aprendizaje, son esenciales en los cambios integrales de esta era. Se determinaron 20 indicadores de su presencia. Se concluye que con esta información cada ente puede elaborar instrumentos que le permitan saber si los valores requeridos están presentes y en caso contrario tomar decisiones que alineen a la organización alrededor de los valores humanistas planteados, incrementando así las posibilidades de éxito en el proceso de cambio y por ende, las posibilidades de supervivencia en esta nueva época.

  5. La formación de la imagen turística inducida: un modelo conceptual

    Directory of Open Access Journals (Sweden)

    Raquel Camprubí

    2009-01-01

    más influyentes para la competitividad de los destinos turísticos, el principal objetivo de este artículo es construir un marco conceptual que muestre la influencia de la red relacional del destino en su imagen emitida. En este contexto, se asume que la imagen turística es una construcción social resultante de la interacción de los distintos agentes que intervienen en el destino turístico (administraciones públicas, instituciones locales, empresas turísticas, etc.; y se propone un modelo teórico para mostrar los efectos de la red relacional del destino turístico en la calidad de la imagen turística creada en términos de conocimiento generado y, por tanto, en su competitividad.

  6. Mutagénesis inducida en microbulbos de Allium sativum L.

    Directory of Open Access Journals (Sweden)

    Adriana Pardo Roldán

    2015-07-01

    Full Text Available Se estableció un protocolo de mutagénesis en microbulbos de ajo (Allium sativum L. clon Boconó cultivado in vitro. Para el efecto se realizaron dos ensayos, uno de radiosensibilidad para establecer la dosimetría apropiada de radiación gamma y otro de mutagénesis para determinar el comportamiento de los materiales hasta la etapa de almacenamiento. En el primero los microbulbos fueron tratados con cuatros dosis de radiación gamma (6, 8, 10 y 12 Krad, más un control. Para establecer la dosis óptima se consideró la sobrevivencia del 50% de los microbulbos (DL50. Se empleó un diseño de bloques al azar con cinco tratamientos y 20 repeticiones por tratamiento. En el ensayo mutagénico los microbulbos fueron irradiados con 8 y 10 Krad y almacenados durante 45 días a 10 °C en condiciones de oscuridad En este caso se utilizó un diseño de bloques al azar con tres tratamientos (0, 8 y 10 Krad y 20 repeticiones por tratamiento. En ambos ensayos, los microbulbos irradiados con 8 y 10 Krad registraron los mayores promedios para peso y diámetro, lo cual permite concluir que estas dosis son adecuadas para favorecer la producción de mutantes con características agronómicas deseables en el clon Boconó

  7. Clinical features of diffuse axonal injury

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To analyze the mechanism of diffuse axonal injury (DAI) and study the relationship between DAI and brain concussion, brain contusion, and primary brain stem injury.Methods: The clinical data and iconographic characteristics of 56 patients with DAI were analyzed retrospectively.Results: Traffic accidents were the main cause of DAI. Among the 56 cases, 34 were injured for at least twice, and 71.43% of the patients were complicated with contusion.Conclusions: It is considered that DAI is a common pattern of primary brain injury, which is often underestimated. And DAI includes cerebral concussion and primary brain injury, and is often complicated by cerebral cortex contusion. Therefore, it is very simple and practical to divide primary brain injuries into local and diffuse injuries.

  8. Evaluación de la reproducción inducida del blanquillo ( Sorubim cuspicaudus Littmann, Burr Nass, 2000 con ovaprim®.

    Directory of Open Access Journals (Sweden)

    Víctor Atencio G

    2003-01-01

    Full Text Available El blanquillo ( Sorubim suspicaudus Littmann, Burr &Nass, 2000 presenta características de importanciapara la acuicultura, destacándose la calidad de sucarne y el alto valor comercial. No se reproduce enconfinamiento, por lo que es necesario sureproducción inducida con sustancias hormonales.Responde bien a la inducción con extracto de pituitariade capa (EPC; sin embargo, no se ha evaluado suinducción con extracto de análogos deGonodotropine Releasing Hormone de salmón(sGnRH-a y domperidone en un vehículo inerte. Porlo tanto, entre mayo y noviembre/02, se evaluó eldesempeño reproductivo del blanquillo inducido condiferentes dosificaciones de Ovaprim®: 0.25 (T2,0.050 (T3 y 0.75 ml/kg de peso vivo (T4, aplicadoen una sola dosificación, por inyección en la basede la aleta pectoral. Además, un grupo fue inducidocon 8 mg EPC/kg de peso vivo (TI, en dos inyeccionesde 10 y7 90% de la dosis total, con intervalo de 6horas, por vía intramuscular. Se indujeron entre seisy nueve hembras por tratamiento con igual númerode machos. El desempeño reproductivo fue evaluadomediante el índice de ovulación (hembras ovuladas/hembras tratadas, tasa de fertilización medida a las4 horas pos-eclosión (HPF, tasa de eclosión medidaa las 10 HPF y la fecundidad tanto absoluta comorelativa. El Ovaprim® mostró ser efectivo para inducirla ovulación del blanquillo en las dosificacionesevaluadas (0.25 a 0.75 mL/kg, con respuestassimilares en el desempeño reproductivo a lasobtenidas en EPC. La ovulación con Ovaprim® seobtuvo entre las 12.8 y 14.0 horas con temperaturapromedio del agua de 27.3ºC. El índice de ovulaciónosciló entre 66.7% (T2 y 83.3% (T3; la tasa defertilización osciló entre 88.0% (T3 y 42.0% (T1; latasa de eclosión osciló entre 83.7% (T3 y 40.3%(T1;la fecundidad absoluta osciló entre 40370.6 (T1 y82992.5 ovocitos/hembra (T2; la fecundad relativa,expresada en gramos de ovocitos/kg de hembra,osciló entre 32.1 (T3 y 63.1(T2; el di

  9. Reproducción extemporánea inducida en borregas de raza Austral

    Directory of Open Access Journals (Sweden)

    M. HERVE

    1997-01-01

    Full Text Available Se utilizaron 84 borregas Austral de 14 meses, con peso promedio de 39.4 ± 3.4 kg, con el objeto de estudiar el efecto de un tratamiento destinado a inducir estro y ovulación extemporáneos, su respuesta reproductiva y productiva y la actividad reproductiva natural en el mes de noviembre. Inicialmente, los animales fueron asignados por muestreo aleatorio en dos grupos de 42 (G1 y G2. G1 fue tratado por 12 días con un dispositivo intravaginal con 0.3 gr. de progesterona y, en el momento de su retiro, se les aplicaron 250 UI de PMSG. 21.4% (9/42 de los animales perdieron el dispositivo y fueron descartados. G2 actuó como control. Al finalizar el tratamiento de inducción, las corderas se manejaron como un solo grupo, encastándose por 34 días con tres carneros Austral, provistos de arneses marcadores. Presentaron celo y fueron montadas 96.9% de las corderas de G1 (40/42 y 9.5% (4/42 de G2. En G1 parió el 75.7% (25/33 durante 7 días, con 159.3% de parición (42 corderos. En G2 no se presentaron partos. El tratamiento utilizado es un buen inductor de celo y ovulación en la época de anestro profundo. La diferencia entre grupos es altamente significativa (p ­ 0.01. La pérdida de dipositivos intravaginales fue extraordinariamente alta. En las condiciones de este experimento, las borregas Austral no presentan una actividad sexual importante en noviembre. No se observaron diferencias significativas en peso y condición corporal entre los animales que parieron 0, 1 ó 2 corderos.The effects of out of season oestrus-ovulation induction treatment were studied in eighty four fourteen month old Austral breed hoggets, weighing 39.4 ± 3.4 kg, through their reproductive and productive response and the natural reproductive activity during November (Spring. Initially, the animals were randomly allocated into 2 groups of 42 each. Group 1 was treated for 12 days with a 0.3 g progesterone intravaginal device and at the moment of withdrawal, injected with

  10. Respuesta productiva de gallinas semipesadas inducidas al descanso ovárico en diferentes edades

    Directory of Open Access Journals (Sweden)

    Luis Galeano V.

    2012-12-01

    Full Text Available Objetivo. Evaluar el efecto de la inducción al descanso ovárico (DO a diferentes edades sobre la respuesta productiva en aves semipesadas productoras de huevo comercial. Materiales y método. Se usaron 840 aves de la línea Hy Line Brown con 64 semanas de edad, distribuidas en 10 tratamientos, consistentes en tres edades (65, 70 y 75 semanas con la aplicación de tres períodos de ayuno (5, 10 y 15 días y un control (sin DO. El análisis estadístico utilizó un modelo completamente aleatorizado, anidado, efecto fijo y balanceado. Se evaluó consumo de calcio durante el ayuno (g/ave/día, consumo de alimento (g/ave/día, porcentaje de producción, peso del huevo (g, conversión por masa de huevo y huevos por ave alojada (HAA. Resultados. La edad presentó efecto significativo (p<0.05 sobre las variables consumo de alimento, día del primer huevo postmuda, días sin producción, día postmuda de retorno al 50% de producción, peso del huevo, número de huevos, masa huevos, conversión y porcentaje de producción (p<0.01. Al comparar con el control, el tratamiento 75-5 presentó efecto significativo (p<0.05 para las variables: consumo de alimento, número de huevos promedio, masa huevos y conversión. Conclusiones. Las aves con mayor período de ayuno presentaron mayor período improductivo postmuda, grandes pérdidas de peso y alto consumo de alimento, lo que genera alta conversión e ineficiencia productiva. En comparación con reportes de literatura sobre DO en aves livianas, las aves semipesadas llegan al cese de producción en menos días y su período improductivo es menor.

  11. Calpains mediate axonal cytoskeleton disintegration during Wallerian degeneration.

    Science.gov (United States)

    Ma, Marek; Ferguson, Toby A; Schoch, Kathleen M; Li, Jian; Qian, Yaping; Shofer, Frances S; Saatman, Kathryn E; Neumar, Robert W

    2013-08-01

    In both the central nervous system (CNS) and peripheral nervous system (PNS), transected axons undergo Wallerian degeneration. Even though Augustus Waller first described this process after transection of axons in 1850, the molecular mechanisms may be shared, at least in part, by many human diseases. Early pathology includes failure of synaptic transmission, target denervation, and granular disintegration of the axonal cytoskeleton (GDC). The Ca(2+)-dependent protease calpains have been implicated in GDC but causality has not been established. To test the hypothesis that calpains play a causal role in axonal and synaptic degeneration in vivo, we studied transgenic mice that express human calpastatin (hCAST), the endogenous calpain inhibitor, in optic and sciatic nerve axons. Five days after optic nerve transection and 48 h after sciatic nerve transection, robust neurofilament proteolysis observed in wild-type controls was reduced in hCAST transgenic mice. Protection of the axonal cytoskeleton in sciatic nerves of hCAST mice was nearly complete 48 h post-transection. In addition, hCAST expression preserved the morphological integrity of neuromuscular junctions. However, compound muscle action potential amplitudes after nerve transection were similar in wild-type and hCAST mice. These results, in total, provide direct evidence that calpains are responsible for the morphological degeneration of the axon and synapse during Wallerian degeneration.

  12. Local erythropoietin signaling enhances regeneration in peripheral axons.

    Science.gov (United States)

    Toth, C; Martinez, J A; Liu, W Q; Diggle, J; Guo, G F; Ramji, N; Mi, R; Hoke, A; Zochodne, D W

    2008-06-23

    Erythropoietin (EPO) and its receptor (EPO-R), mediate neuroprotection from axonopathy and apoptosis in the peripheral nervous system (PNS). We examined the impact and potential mechanisms of local EPO signaling on regenerating PNS axons in vivo and in vitro. As a consequence of injury, peripheral nerve axons and DRG neurons have a marked increase in the expression of EPO and EPO-R. Local delivery of EPO via conduit over 2 weeks to rat sciatic nerve following crush injury increased the density and maturity of regenerating myelinated axons growing distally from the crush site. In addition, EPO also rescued retrograde degeneration and atrophy of axons. EPO substantially increased the density and intensity of calcitonin gene-related peptide (CGRP) expression within outgrowing axons. Behavioral improvements in sensorimotor function also occurred in rats exposed to near nerve EPO delivery. EPO delivery led to decreased nuclear factor kappaB (NFkB) activation but increased phosphorylation of Akt and STAT3 within nerve and dorsal root ganglia neurons indicating rescue from an injury phenotype. Spinal cord explant studies also demonstrated a similar dose-dependent effect of EPO upon motor axonal outgrowth. Local EPO signaling enhances regenerating peripheral nervous system axons in addition to its known neuroprotection. Exogenous EPO may have a therapeutic role in a large number of peripheral nerve diseases through its impact on regeneration.

  13. Respuesta inmune sistémica y mucosal contra Neisseria meningitidis B inducida por estrategia de vacunación simultánea mucosal y parental

    Directory of Open Access Journals (Sweden)

    González E

    2009-08-01

    Full Text Available mmunization is one of the most successful and cost-effective health interventions ever. Immunization have been helping to reduce child mortality, improving maternal health and combating infectious diseases. In spite of its, undisputed past success and promising future, however, immunization remains an unfinished agenda because of them inadequate coverage. Several factors have been largely responsible of a difficulty to attain immunization coverage and have been recognized as a problems of current vaccines, such as: the number of dose, excessive use of parenteral route, a small number of adjuvants approve for use in human, higher reactogenicity and unavailability against intracellular pathogens, infected or altered cells and scanty feasibility to combined more than one antigen in the same formulation. For bacterial meningitis WHO estimates that 1.2 million cases occur annually and Neisseria meningitidis is the etiological agent in more than 40% of these cases although some meningococcal vaccines are available. To bear in mind these principals problems, a novel protocol for vaccination against N. meningitidis called Single Time Vaccination Strategy (SinTimVaS is proposed. Using female BALB/c mice, we induce systemic and mucosal immune responses against N. meningitidis with only one parenteral and one mucosal dose at the same time, employing the Finlay Adjuvants derivate from N. meningitidis, AFPL1 and AFCo1, respectively. In conclusion, SinTimVaS could increase the vaccination coverage and reduce the time-cost of vaccine campaigns, adding the possibility to increase the herd immunity by mucosal specific response induction.

  14. Alteraciones histológicas y neuroquímicas inducidas en el cuerpo estriado por la exposición a sulfonato de perfluoroctano (PFOS)

    OpenAIRE

    A. Lafuente; N. Pereiro; N. Echegaray; Carrera, L; Blanco, A.; A. Hardisson; Moyano, R.

    2013-01-01

    El sulfonato de perfluoroctano (PFOS) es un compuesto organofluorado y está considerado como un contaminante orgánico persistente. Atraviesa la barrera hematoencefálica y es capaz de incrementar su propio transporte a través de la misma, alcanzando así el sistema nervioso central, donde ejerce su toxicidad. El objetivo de este trabajo es evaluar la neurotoxicidad del PFOS en cuerpo estriado a nivel neuroquímico e histológico. Para ello, este xenobiótico se ha administrado oralmente durante 28...

  15. Ácido lipoico revierte estrés oxidativo y corrige alteraciones del metabolismo hidrocarbonado y lipídico inducidas por dieta rica en fructosa (DRF)

    OpenAIRE

    Castro, María Cecilia; Francini,Flavio; Schinella, Guillermo; Castrogiovanni, D.; Gagliardino, Juan José; Massa, María Laura

    2010-01-01

    Estudios previos de nuestro grupo de trabajo sugieren que la administración de una DRF induce aumento en la producción de especies reactivas de oxígeno (ROS) y, consecuentemente EO, así como alteraciones del metabolismo hepático de carbohidratos y lípidos. El mencionado aumento del EO se asocia a un aumento en la concentración sérica de triglicéridos (TG), insulinorresistencia (IR) y tolerancia a la glucosa alterada. El objetivo del presente trabajo fue evaluar el efecto de la administración ...

  16. Calcio-ácido linoleico en la prevención de la preeclampsia y la hipertension arterial inducida por el embarazo.

    Directory of Open Access Journals (Sweden)

    Julián A. Herrera M

    2009-10-01

    Full Text Available En 12 centros de salud de Cali, se hizo un ensayo clínico controlado, al azar, que incluyó 91 gestantes primigrávidas, normotensas, con alto riesgo biopsicosocial, una prueba de presión arterial supina positiva y una presión arterial media alta. Las futuras madres se asignaron a 3 grupos: 43 (47.2% al grupo de intervención (Grupo A: calcio elemental, 600 mg, ácido linoleico, 450 mg; y 48 (52.7% a 2 grupos controles [Grupo B: 24 (26.3%, con intervención psicosocial y placebo; Grupo C: otras 24 (26.3% que recibieron doble placebo.] Para comenzar el estudio se hizo una evaluación obstétrica y nutricional, con evaluación prospectiva del resultado perinatal. La edad promedio fue 21.1±4.9 años; no hubo diferencias estadísticas en las variables sociodemográficas. Del total, 20 (21.9% pacientes desarrollaron HIEP; en el Grupo A, 4 (9.3% [RR = 0.22 (i.c. 95% 0.08 - 0.64, p = 0.001]; en el Grupo control B, 4 (16.7%; y en el Grupo control C, 12 (50.0%. El calcio elemental y el ácido linoleico en dosis bajas, durante el tercer trimestre del embarazo, disminuyeron significativamente la incidencia de preeclampsia en pacientes con alto riesgo de desarrollarla.

  17. Asma inducida por ejercicio: Diferencias en la percepciónde síntomas entre pacientes pediátricos y sus padres

    OpenAIRE

    Brockmann V,Pablo; Fodor O,Daniel; Caussade L,Solange; Campos M,Eugenia; Bertrand N,Pablo

    2006-01-01

    Background: Exercise is a frequent trigger of symptoms in asthmatic children and it worsens their quality of life. Aim: To compare the perception about exercise among asthmatic pediatric patients and their parents. Material and methods: Asthmatic patients with symptoms related to exercise, were tested with an exercise challenge test following the Tal protocol. Before testing, a questionnaire about symptoms triggered by exercise was answered by children and their parents. The data was analyzed...

  18. Thermoluminescence induced by X-rays in silica materials with metallic impurities; Termoluminiscencia inducida por los rayos X en materiales de silice con impurezas metalicas

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza A, D.; Gonzalez M, P.; Espinosa P, M. [Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, Mexico D.F. (Mexico); Salas, P.; Castano, V.M. [Instituto de Fisica, UNAM, Laboratorio Juriquilla, A.P. 1-1010, C.P. 76001, Queretaro (Mexico)

    1999-07-01

    Diverse materials of silica with Fe, Cu, Mg, and Mn impurities were synthesized by the sol-gel method, using tetraethyl orthosilicate as precursor. The materials obtained were subjected to thermal treatment at 500, 700 and 1000 Centigrade also they were irradiated with X-ray generated by a X-ray diffractometer which is installed in the ININ. The thermoluminescent signal was analysed and correlated with the type of impurities that are present in the material and with the grade of crystallinity produced by the thermal treatment in them. In according to the results obtained these materials show a thermoluminescent signal which is influenced by the crystallinity grade. It was analysed the behavior of the response for different doses, with the purpose of utilizing them to quantify very intense fields of radiation. (Author)

  19. XANTATINA INHIBE LA ACTIVACIÓN DE MASTOCITOS INDUCIDA POR NEUROPÉPTIDOS PRO-INFLAMATORIOS. XANTHATIN INHIBITS MAST CELL ACTIVATION INDUCED BY PRO-INFLAMMATORY NEUROPEPTIDES

    OpenAIRE

    Carlos E. Tonn; Alicia B. Penissi; Teresa H Fogal; Elia Martino; Patricia M Vargas

    2010-01-01

    Mast cells are connective tissue cells involved in the genesis and modulation of inflammatory responses. We have previously shown that xanthatin (xanthanolide sesquiterpene isolated from Xanthium cavanillesii Schouw) inhibits mast cell activation induced by experimental secretagogues. However, the effect of xanthatin on mast cell activation induced by pathophysiological stimuli remains unknown. These stimuli include, among others, the pro-inflammatory neuropeptide substance P and neurotensin,...

  20. Acute pancreatitis induced by hypertriglyceridemia and treatment with plasmapheresis: case report = Pancreatitis aguda inducida por hipertrigliceridemia y tratamiento con plasmaféresis: reporte de un caso

    Directory of Open Access Journals (Sweden)

    Muñoz Ortiz, Édison

    2012-10-01

    Full Text Available Hypertriglyceridemia (HTG is a potential cause of acute pancreatitis (AP, especially when its values are greater than 1.000 mg/dL. Different therapeutic measures have been proposed for patients with AP secondary to HTG, including the one that seems to be more effective: plasmapheresis. We report the case of a patient with severe HTG (triglycerides 6.480 mg/dL that suffered from AP, and had favorable evolution with plasmapheresis.

  1. Evolución cicatricial de úlceras cutáneas experimentales inducida por productos clínicos de limpieza de heridas

    OpenAIRE

    Chacón Ferrera, R.

    2013-01-01

    Programa de doctorado: Avances en Traumatología, Medicina del Deporte y Cuidados de Heridas [ES] Se plantea esta tesis con la finalidad de valorar la relación existente entre los diferentes productos clónicos utilizados en la limpieza de heridas (Agua destilada, Agua oxigenada, Suero fisiológico y Suero Glucosado), y su influencia sobre la evolución cicatricial. Para ello, se hace un recorrido conceptual de las heridas y sus diferentes métodos de resolución, haciendo hincapié en el proceso...

  2. El pretratamiento agudo y subcrónico con fármacos anticonvulsivantes modifica las crisis generalizadas inducidas por el pentilenetetrazol en el ratón.

    Directory of Open Access Journals (Sweden)

    Luisa L. Rocha

    2009-11-01

    Full Text Available Objetives: The increased GABA content or administration of a centrally active GABA-mimetic agent have been used as a efficacious anticonvulsant therapeutic approach. However, it has been suggested that the use of drugs that continually and noncontingently alter synaptic transmission could alter at the nervous system. The present study was carried out to investigate the effects of acute (one administration and subchronic (7 daily administrations treatments with Diazepam (DZP; 10 mg/kg, ip, Gabapentin (GBP, 100 mg/kg. vo and Vigabatrin (VGB, 500 mg/kg, vo on pentylenetetrazol-induced generalized seizures (PTZ, 80 mg/kg, ip. Materials and methods: Male Taconic mice (20-25 g received acute or subchronic treatment with DZP, VGB or GBP and 24 h after the last administration, the effects of PTZ (latency to the clonus, forelimb extension and death incidence were evaluated. Results: Acute DZP protected all animals (100% to the convulsant effects of PTZ, whereas subchronic DZP decreased the latency to the clonic (21%; p Conclusions: The present results indicate that the acute pretreatment with drugs enhancing GABAergic transmission differently modifies the seizure susceptibility, and that the subchronic administration may facilitate the seizure activity.

  3. Axon guidance and neuronal migration research in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Proper migration of neuronal somas and axonal growth cones to designated locations in the developing brain is essential for the assembly of functional neuronal circuits.Rapid progress in research of axon guidance and neuronal migration has been made in the last twenty years.Chinese researchers began their exploration in this field ten years ago and have made significant contributions in clarifying the signal transduction of axon guidance and neuronal migration.Several unique experimental approaches,including the migration assay of single isolated neurons in response to locally delivered guidance cues,have been developed by Chinese neuroscientists to investigate the molecular machinery underlying these guidance events.

  4. Pérdida auditiva por contaminación acústica laboral en Santiago de Chile

    OpenAIRE

    2013-01-01

    [spa] La Organización Mundial de la Salud (OMS) ha estimado que, aproximadamente, 278 millones de personas presentan déficit auditivo en el mundo; que el 50% de las pérdidas auditivas podrían evitarse mediante prevención, un diagnóstico precoz y una gestión eficaz y que, más de 4.000.000 de años de vida saludable se perdieron debido a las pérdidas auditivas inducidas por ruido. Lo anterior hace necesario establecer un modelo para predecir la pérdida auditiva por contaminación acústica laboral...

  5. Action potentials initiate in the axon initial segment and propagate through axon collaterals reliably in cerebellar Purkinje neurons.

    Science.gov (United States)

    Foust, Amanda; Popovic, Marko; Zecevic, Dejan; McCormick, David A

    2010-05-19

    Purkinje neurons are the output cells of the cerebellar cortex and generate spikes in two distinct modes, known as simple and complex spikes. Revealing the point of origin of these action potentials, and how they conduct into local axon collaterals, is important for understanding local and distal neuronal processing and communication. By using a recent improvement in voltage-sensitive dye imaging technique that provided exceptional spatial and temporal resolution, we were able to resolve the region of spike initiation as well as follow spike propagation into axon collaterals for each action potential initiated on single trials. All fast action potentials, for both simple and complex spikes, whether occurring spontaneously or in response to a somatic current pulse or synaptic input, initiated in the axon initial segment. At discharge frequencies of less than approximately 250 Hz, spikes propagated faithfully through the axon and axon collaterals, in a saltatory manner. Propagation failures were only observed for very high frequencies or for the spikelets associated with complex spikes. These results demonstrate that the axon initial segment is a critical decision point in Purkinje cell processing and that the properties of axon branch points are adjusted to maintain faithful transmission.

  6. Npn-1 contributes to axon-axon interactions that differentially control sensory and motor innervation of the limb.

    Directory of Open Access Journals (Sweden)

    Rosa-Eva Huettl

    2011-02-01

    Full Text Available The initiation, execution, and completion of complex locomotor behaviors are depending on precisely integrated neural circuitries consisting of motor pathways that activate muscles in the extremities and sensory afferents that deliver feedback to motoneurons. These projections form in tight temporal and spatial vicinities during development, yet the molecular mechanisms and cues coordinating these processes are not well understood. Using cell-type specific ablation of the axon guidance receptor Neuropilin-1 (Npn-1 in spinal motoneurons or in sensory neurons in the dorsal root ganglia (DRG, we have explored the contribution of this signaling pathway to correct innervation of the limb. We show that Npn-1 controls the fasciculation of both projections and mediates inter-axonal communication. Removal of Npn-1 from sensory neurons results in defasciculation of sensory axons and, surprisingly, also of motor axons. In addition, the tight coupling between these two heterotypic axonal populations is lifted with sensory fibers now leading the spinal nerve projection. These findings are corroborated by partial genetic elimination of sensory neurons, which causes defasciculation of motor projections to the limb. Deletion of Npn-1 from motoneurons leads to severe defasciculation of motor axons in the distal limb and dorsal-ventral pathfinding errors, while outgrowth and fasciculation of sensory trajectories into the limb remain unaffected. Genetic elimination of motoneurons, however, revealed that sensory axons need only minimal scaffolding by motor axons to establish their projections in the distal limb. Thus, motor and sensory axons are mutually dependent on each other for the generation of their trajectories and interact in part through Npn-1-mediated fasciculation before and within the plexus region of the limbs.

  7. Npn-1 contributes to axon-axon interactions that differentially control sensory and motor innervation of the limb.

    Science.gov (United States)

    Huettl, Rosa-Eva; Soellner, Heidi; Bianchi, Elisa; Novitch, Bennett G; Huber, Andrea B

    2011-02-01

    The initiation, execution, and completion of complex locomotor behaviors are depending on precisely integrated neural circuitries consisting of motor pathways that activate muscles in the extremities and sensory afferents that deliver feedback to motoneurons. These projections form in tight temporal and spatial vicinities during development, yet the molecular mechanisms and cues coordinating these processes are not well understood. Using cell-type specific ablation of the axon guidance receptor Neuropilin-1 (Npn-1) in spinal motoneurons or in sensory neurons in the dorsal root ganglia (DRG), we have explored the contribution of this signaling pathway to correct innervation of the limb. We show that Npn-1 controls the fasciculation of both projections and mediates inter-axonal communication. Removal of Npn-1 from sensory neurons results in defasciculation of sensory axons and, surprisingly, also of motor axons. In addition, the tight coupling between these two heterotypic axonal populations is lifted with sensory fibers now leading the spinal nerve projection. These findings are corroborated by partial genetic elimination of sensory neurons, which causes defasciculation of motor projections to the limb. Deletion of Npn-1 from motoneurons leads to severe defasciculation of motor axons in the distal limb and dorsal-ventral pathfinding errors, while outgrowth and fasciculation of sensory trajectories into the limb remain unaffected. Genetic elimination of motoneurons, however, revealed that sensory axons need only minimal scaffolding by motor axons to establish their projections in the distal limb. Thus, motor and sensory axons are mutually dependent on each other for the generation of their trajectories and interact in part through Npn-1-mediated fasciculation before and within the plexus region of the limbs.

  8. Structural plasticity of axon terminals in the adult.

    Science.gov (United States)

    Gogolla, Nadine; Galimberti, Ivan; Caroni, Pico

    2007-10-01

    There is now conclusive evidence for widespread ongoing structural plasticity of presynaptic boutons and axon side-branches in the adult brain. The plasticity complements that of postsynaptic spines, but axonal plasticity samples larger volumes of neuropil, and has a larger impact on circuit remodeling. Axons from distinct neurons exhibit unique ratios of stable (t1/2>9 months) and dynamic (t1/2 5-20 days) boutons, which persist as spatially intermingled subgroups along terminal arbors. In addition, phases of side-branch dynamics mediate larger scale remodeling guided by synaptogenesis. The plasticity is most pronounced during critical periods; its patterns and outcome are controlled by Hebbian mechanisms and intrinsic neuronal factors. Novel experience, skill learning, life-style, and age can persistently modify local circuit structure through axonal structural plasticity.

  9. Sodium Channels, Mitochondria, and Axonal Degeneration in Peripheral Neuropathy.

    Science.gov (United States)

    Persson, Anna-Karin; Hoeijmakers, Janneke G J; Estacion, Mark; Black, Joel A; Waxman, Stephen G

    2016-05-01

    Peripheral neuropathy results from damage to peripheral nerves and is often accompanied by pain in affected limbs. Treatment represents an unmet medical need and a thorough understanding of the mechanisms underlying axonal injury is needed. Longer nerve fibers tend to degenerate first (length-dependence), and patients carrying pathogenic mutations throughout life usually become symptomatic in mid- or late-life (time-dependence). The activity of voltage-gated sodium channels can contribute to axonal injury and sodium channel gain-of-function mutations have been linked to peripheral neuropathy. Recent studies have implicated sodium channel activity, mitochondrial compromise, and reverse-mode Na(+)/Ca(2+) exchange in time- and length-dependent axonal injury. Elucidation of molecular mechanisms underlying axonal injury in peripheral neuropathy may provide new therapeutic strategies for this painful and debilitating condition.

  10. Morphology of axonal transport abnormalities in primate eyes.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1981-11-01

    The ultrastructure of the retina and optic nerve head was studied in primate eyes after central retinal artery occlusion. Within 2 hours of the vascular occlusion the inner retinal layers undergo watery (isosmotic) swelling. This watery swelling of axons and astroglia extends into the nerve head as far back as the anterior boundary of the scleral lamina cribrosa. The swelling is increased 4 hours after the occlusion, and by 24 hours disintegration has occurred. At the optic nerve head mitochondria and vesicles of smooth endoplasmic reticulum begin to accumulate within 2 hours. The accumulation increases at 4 hours and persists to 24 hours. The watery swelling seems characteristic of ischaemic axons. Membranous organelles accumulate at the boundary of an ischaemic zone when material carried by axonal transport is brought via the healthy axon segment to the boundary, but they cannot proceed further into the ischaemic zone. Such accumulation is typical of locations where rapid orthograde axonal transport or retrograde axonal transport is blocked. In contrast, when slow axonal flow is impaired, the swelling is characterised by an excess of cytoplasmic gel without a marked accumulation of organelles. Rapid orthograde transport and retrograde transport seem to be closely related to one another, while slow axoplasmic flow seems fundamentally different. From morphological findings we suspect that, in experimental glaucoma, intraocular pressure first affects the intracellular physiological process of rapid orthograde and retrograde axonal transport. Watery swelling may not occur unless the ischaemic injury to cell metabolism is more advanced. In contrast, in experimental papilloedema, the swelling results predominantly from impaired slow axoplasmic flow.

  11. Modality-Specific Axonal Regeneration: Towards selective regenerative neural interfaces

    Directory of Open Access Journals (Sweden)

    Parisa eLotfi

    2011-10-01

    Full Text Available Regenerative peripheral nerve interfaces have been proposed as viable alternatives for the natural control of robotic prosthetic devices. However, sensory and motor axons at the neural interface are of mixed submodality types, which difficult the specific recording from motor axons and the eliciting of precise sensory modalities through selective stimulation. Here we evaluated the possibility of using type-specific neurotrophins to preferentially entice the regeneration of defined axonal populations from transected peripheral nerves into separate compartments. Segregation of mixed sensory fibers from dorsal root ganglion neurons was evaluated in vitro by compartmentalized diffusion delivery of nerve growth factor (NGF and neurotrophin-3 (NT-3, to preferentially entice the growth of TrkA+ nociceptive and TrkC+ proprioceptive subsets of sensory neurons, respectively. The average axon length in the NGF channel increased 2.5 fold compared to that in saline or NT-3, whereas the number of branches increased 3 fold in the NT-3 channels. These results were confirmed using a 3-D Y-shaped in vitro assay showing that the arm containing NGF was able to entice a 5-fold increase in axonal length of unbranched fibers. To address if such segregation can be enticed in vivo, a Y-shaped tubing was used to allow regeneration of the transected adult rat sciatic nerve into separate compartments filled with either NFG or NT-3. A significant increase in the number of CGRP+ pain fibers were attracted towards the sural nerve, while N-52+ large diameter axons were observed in the tibial and NT-3 compartments. This study demonstrates the guided enrichment of sensory axons in specific regenerative chambers, and supports the notion that neurotrophic factors can be used to segregate sensory and perhaps motor axons in separate peripheral interfaces.

  12. Electrophysiology of a nonmyelinated glutamatergic axon in rat hippocampus

    OpenAIRE

    Alle, Henrik

    2012-01-01

    The common theme of the presented work on the nonmyelinated hippocampal mossy fiber (the axon of the granule cell in the dentate gyrus) is the generation of subthreshold and suprathreshold electrical signals. Subthreshold depolarizations in the axon can occur due to passive propagation of excitatory postsynaptic potentials, which are generated in the somato-dendritic domain. The remote passive propagation of these comparatively slow but transient signals is due to a space constant...

  13. 6-Sulphated chondroitins have a positive influence on axonal regeneration.

    Directory of Open Access Journals (Sweden)

    Rachel Lin

    Full Text Available Chondroitin sulphate proteoglycans (CSPGs upregulated in the glial scar inhibit axon regeneration via their sulphated glycosaminoglycans (GAGs. Chondroitin 6-sulphotransferase-1 (C6ST-1 is upregulated after injury leading to an increase in 6-sulphated GAG. In this study, we ask if this increase in 6-sulphated GAG is responsible for the increased inhibition within the glial scar, or whether it represents a partial reversion to the permissive embryonic state dominated by 6-sulphated glycosaminoglycans (GAGs. Using C6ST-1 knockout mice (KO, we studied post-injury changes in chondroitin sulphotransferase (CSST expression and the effect of chondroitin 6-sulphates on both central and peripheral axon regeneration. After CNS injury, wild-type animals (WT showed an increase in mRNA for C6ST-1, C6ST-2 and C4ST-1, but KO did not upregulate any CSSTs. After PNS injury, while WT upregulated C6ST-1, KO showed an upregulation of C6ST-2. We examined regeneration of nigrostriatal axons, which demonstrate mild spontaneous axon regeneration in the WT. KO showed many fewer regenerating axons and more axonal retraction than WT. However, in the PNS, repair of the median and ulnar nerves led to similar and normal levels of axon regeneration in both WT and KO. Functional tests on plasticity after the repair also showed no evidence of enhanced plasticity in the KO. Our results suggest that the upregulation of 6-sulphated GAG after injury makes the extracellular matrix more permissive for axon regeneration, and that the balance of different CSs in the microenvironment around the lesion site is an important factor in determining the outcome of nervous system injury.

  14. Fast and reliable identification of axons, axon initial segments and dendrites with local field potential recording

    DEFF Research Database (Denmark)

    Petersen, Anders V.; Johansen, Emil O.; Perrier, Jean-Francois

    2015-01-01

    The axon initial segment (AIS) is an essential neuronal compartment. It is usually where action potentials are initiated. Recent studies demonstrated that the AIS is a plastic structure that can be regulated by neuronal activity and by the activation of metabotropic receptors. Studying the AIS...... of neurons, we can detect sinks caused by inward currents flowing across the membrane. We determine the location of the AIS by comparing the timing of these events with the action potential. We demonstrate that this method allows the unequivocal identification of the AIS of different types of neurons from...

  15. Axon-glia interaction and membrane traffic in myelin formation.

    Science.gov (United States)

    White, Robin; Krämer-Albers, Eva-Maria

    2014-01-06

    In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialized glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarization followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is established. Continuous communication between neurons and glial cells is essential for myelin maintenance and axonal integrity. A diverse group of diseases, from multiple sclerosis to schizophrenia, have been linked to malfunction of myelinating cells reflecting the physiological importance of the axon-glial unit. This review describes the mechanisms of axonal signal integration by oligodendrocytes emphasizing the central role of the Src-family kinase Fyn during central nervous system (CNS) myelination. Furthermore, we discuss myelin membrane trafficking with particular focus on endocytic recycling and the control of proteolipid protein (PLP) transport by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Finally, PLP mistrafficking is considered in the context of myelin diseases.

  16. Axon morphology at the lamina cribrosa in monkey eyes.

    Science.gov (United States)

    Radius, R L; Klewin, K M

    1986-01-01

    The eyes of 8 monkeys (Aotus trivirgatus) were studied. The mean cross-section area and the least diameter of axon cylinders were calculated from measurements made by computer assisted planimetry of electron photomicrographs of sections through the optic nerve head at the level of the lamina cribrosa. The density of intrabundle connective tissue and glial cell elements in nerve fiber bundles was also calculated. The mean cross-section area and minimum diameter of axons in the temporal part were less than in the nasal part of the nerve. The values for axons in the superior and inferior parts of the nerve were intermediate. A similar pattern of increasing dimensions was seen in axons from the more axial nerve compared to neurons in the more circumferential nerve sectors. The density of the intrabundle, nonaxonal tissue elements did not differ significantly across the nerve. Although axon dimensions may play some role in defining the vulnerability of neuronal tissue to a pressure insult, the results of this anatomic investigation do not support the hypothesis that differences in axonal distribution by size across the nerve section define the regional vulnerability of the nerve head to elevated intraocular pressure.

  17. Axon-glia interaction and membrane traffic in myelin formation

    Directory of Open Access Journals (Sweden)

    Robin eWhite

    2014-01-01

    Full Text Available In vertebrate nervous systems myelination of neuronal axons has evolved to increase conduction velocity of electrical impulses with minimal space and energy requirements. Myelin is formed by specialised glial cells which ensheath axons with a lipid-rich insulating membrane. Myelination is a multi-step process initiated by axon-glia recognition triggering glial polarisation followed by targeted myelin membrane expansion and compaction. Thereby, a myelin sheath of complex subdomain structure is established. Continuous communication between neurons and glial cells is essential for myelin maintenance and axonal integrity. A diverse group of diseases, from multiple sclerosis to schizophrenia, have been linked to malfunction of myelinating cells reflecting the physiological importance of the axon-glial unit. This review describes the mechanisms of axonal signal integration by oligodendrocytes emphasising the central role of the Src-family kinase Fyn during CNS myelination. Furthermore, we discuss myelin membrane trafficking with particular focus on endocytic recycling and the control of PLP (proteolipid protein transport by SNARE proteins. Finally, PLP mistrafficking is considered in the context of myelin diseases.

  18. Uncovering sensory axonal dysfunction in asymptomatic type 2 diabetic neuropathy.

    Science.gov (United States)

    Sung, Jia-Ying; Tani, Jowy; Chang, Tsui-San; Lin, Cindy Shin-Yi

    2017-01-01

    This study investigated sensory and motor nerve excitability properties to elucidate the development of diabetic neuropathy. A total of 109 type 2 diabetes patients were recruited, and 106 were analyzed. According to neuropathy severity, patients were categorized into G0, G1, and G2+3 groups using the total neuropathy score-reduced (TNSr). Patients in the G0 group were asymptomatic and had a TNSr score of 0. Sensory and motor nerve excitability data from diabetic patients were compared with data from 33 healthy controls. Clinical assessment, nerve conduction studies, and sensory and motor nerve excitability testing data were analyzed to determine axonal dysfunction in diabetic neuropathy. In the G0 group, sensory excitability testing revealed increased stimulus for the 50% sensory nerve action potential (Pmotor excitability only had significantly increased stimulus for the 50% compound motor nerve action potential (Pdevelopment of axonal dysfunction in sensory axons occurred prior to and in a different fashion from motor axons. Additionally, sensory nerve excitability tests can detect axonal dysfunction even in asymptomatic patients. These insights further our understanding of diabetic neuropathy and enable the early detection of sensory axonal abnormalities, which may provide a basis for neuroprotective therapeutic approaches.

  19. Ultrastructural observation of effect of moderate hypothermia on axonal damage in an animal model of diffuse axonal injury

    Institute of Scientific and Technical Information of China (English)

    孙晓川; 唐文渊; 郑履平

    2002-01-01

    Objective: To investigate the effect of moderate hypothermia on responses of axonal cytoskeleton to axonal injury in the acute stage of injury. Methods: Of fifteen adult guinea pigs, twelve animals were subjected to stretch injury to the right optic nerves and divided into the normothermic group (n=6) in which the animal's core temperature was maintained at 36.0-37.5℃ and the hypothermia group (n=6) in which the core temperature was reduced to 32.0-32.5℃ after stretch injury. Remaining three animals sustained no injury to the right optic nerves and served as control group. Half of injured animals (n=3) of either normothermic group or hypothermic group were killed at either 2 hours or 4 hours after injury. The ultrastructural changes of axonal cytoskeleton of the right optic nerve fibers from the animals were examined under a transmission electron microscope and analyzed by quantitative analysis with a computer image analysis system. Results: At 2 hours after stretch injury, there was a significant reduction in the mean number of microtubules (P<0.001), and a significant increase in the mean intermicrotubule spacing (P<0.05 or P<0.01) in axons of all sizes in normothermic animals. The mean number of neurofilaments also decreased statistically (P<0.01) in large and medium subgroups of axons in the same experimental group at 2 hours. By 4 hours, the large subgroup of axons in normothermic animals still demonstrated a significant decline in the mean number of microtubules (P<0.01) and an increase in the mean intermicrotubule spacing (P<0.05), while the medium and small subgroups of axons displayed a significant increase in the mean number of neurofilaments (P<0.05) and reduction in the mean interneurofilament spacing (P<0.05). On the contrary, either the mean number of microtubules and the mean intermicrotubule spacing, or the mean number of neurofilaments and interneurofilament spacing in axons of all sizes in hypothermic stretch-injured animals was not

  20. Reducción del colesterol y aumento de la capacidad antioxidante por el consumo crónico de maíz morado (Zea mays L) en ratas hipercolesterolémicas

    OpenAIRE

    Jorge Arroyo; Ernesto Raez; Miguel. Rodríguez; Víctor Chumpitaz; Jonny Burga; Walter De la Cruz; José Valencia

    2007-01-01

    Objetivos: Determinar la actividad hipocolesterolémica y antioxidante del consumo crónico del extracto hidroalcohólico atomizado del maíz morado (Zea mays L) en ratas hipercolesterolémicas. Materiales y métodos: Se utilizaron cinco grupos de seis ratas Holtzmann cada uno, uno sin hipercolesterolemia (control negativo), y cuatro con hipercolesterolemia inducida por consumo de colesterol puro vía oral durante 60 días: control positivo y tres para las dosis de 250, 500 y 1000 mg/kg, respectivame...

  1. Microangiopatía trombótica y hemólisis intravascular en hipertensión por embarazo. La mentira del síndrome de HELLP

    OpenAIRE

    Manuel Antonio Díaz de León-Ponce; Jesús Carlos Briones-Garduño; José Meneses-Calderón; Armando Alberto Moreno-Santillán

    2006-01-01

    Se revisó la literatura nacional e internacional sobre hipertensión inducida por el embarazo y su relación con la microangiopatía trombótica y hemólisis intravascular (MTHI). En el presente trabajo se describen los antecedentes históricos, frecuencia, mortalidad, cuadro clínico, clasificación, diagnóstico, complicaciones y tratamientos. Además, se analizó el reporte de Weinstein de 1982 y se concluyó que los datos que reportó como síndrome de HELLP no son contundentes en demostrar que sus pac...

  2. White matter involvement after TBI: Clues to axon and myelin repair capacity.

    Science.gov (United States)

    Armstrong, Regina C; Mierzwa, Amanda J; Marion, Christina M; Sullivan, Genevieve M

    2016-01-01

    Impact-acceleration forces to the head cause traumatic brain injury (TBI) with damage in white matter tracts comprised of long axons traversing the brain. White matter injury after TBI involves both traumatic axonal injury (TAI) and myelin pathology that evolves throughout the post-injury time course. The axon response to initial mechanical forces and secondary insults follows the process of Wallerian degeneration, which initiates as a potentially reversible phase of intra-axonal damage and proceeds to an irreversible phase of axon fragmentation. Distal to sites of axon disconnection, myelin sheaths remain for prolonged periods, which may activate neuroinflammation and inhibit axon regeneration. In addition to TAI, TBI can cause demyelination of intact axons. These evolving features of axon and myelin pathology also represent opportunities for repair. In experimental TBI, demyelinated axons exhibit remyelination, which can serve to both protect axons and facilitate recovery of function. Myelin remodeling may also contribute to neuroplasticity. Efficient clearance of myelin debris is a potential target to attenuate the progression of chronic pathology. During the early phase of Wallerian degeneration, interventions that prevent the transition from reversible damage to axon disconnection warrant the highest priority, based on the poor regenerative capacity of axons in the CNS. Clinical evaluation of TBI will need to address the challenge of accurately detecting the extent and stage of axon damage. Distinguishing the complex white matter changes associated with axons and myelin is necessary for interpreting advanced neuroimaging approaches and for identifying a broader range of therapeutic opportunities to improve outcome after TBI.

  3. Atomic Force Microscopy Reveals Important Differences in Axonal Resistance to Injury

    Science.gov (United States)

    Magdesian, Margaret H.; Sanchez, Fernando S.; Lopez, Monserratt; Thostrup, Peter; Durisic, Nela; Belkaid, Wiam; Liazoghli, Dalinda; Grütter, Peter; Colman, David R.

    2012-01-01

    Axonal degeneration after traumatic brain injury and nerve compression is considered a common underlying cause of temporary as well as permanent disability. Because a proper functioning of neural network requires phase coherence of all components, even subtle changes in circuitry may lead to network failure. However, it is still not possible to determine which axons will recover or degenerate after injury. Several groups have studied the pressure threshold for axonal injury within a nerve, but difficulty accessing the injured region; insufficient imaging methods and the extremely small dimensions involved have prevented the evaluation of the response of individual axons to injury. We combined microfluidics with atomic force microscopy and in vivo imaging to estimate the threshold force required to 1), uncouple axonal transport without impairing axonal survival, and 2), compromise axonal survival in both individual and bundled axons. We found that rat hippocampal axons completely recover axonal transport with no detectable axonal loss when compressed with pressures up to 65 ± 30 Pa for 10 min, while dorsal root ganglia axons can resist to pressures up to 540 ± 220 Pa. We investigated the reasons for the differential susceptibility of hippocampal and DRG axons to mechanical injury and estimated the elasticity of live axons. We found that dorsal root ganglia axons have a 20% lower elastic modulus than hippocampal axons. Our results emphasize the importance of the integrity of the axonal cytoskeleton in deciding the axonal fate after damage and open up new avenues to improve injury diagnosis and to identify ways to protect axons. PMID:22947856

  4. Axonal synapses utilize multiple synaptic ribbons in the mammalian retina.

    Directory of Open Access Journals (Sweden)

    Hong-Lim Kim

    Full Text Available In the mammalian retina, bipolar cells and ganglion cells which stratify in sublamina a of the inner plexiform layer (IPL show OFF responses to light stimuli while those that stratify in sublamina b show ON responses. This functional relationship between anatomy and physiology is a key principle of retinal organization. However, there are at least three types of retinal neurons, including intrinsically photosensitive retinal ganglion cells (ipRGCs and dopaminergic amacrine cells, which violate this principle. These cell types have light-driven ON responses, but their dendrites mainly stratify in sublamina a of the IPL, the OFF sublayer. Recent anatomical studies suggested that certain ON cone bipolar cells make axonal or ectopic synapses as they descend through sublamina a, thus providing ON input to cells which stratify in the OFF sublayer. Using immunoelectron microscopy with 3-dimensional reconstruction, we have identified axonal synapses of ON cone bipolar cells in the rabbit retina. Ten calbindin ON cone bipolar axons made en passant ribbon synapses onto amacrine or ganglion dendrites in sublamina a of the IPL. Compared to the ribbon synapses made by bipolar terminals, these axonal ribbon synapses were characterized by a broad postsynaptic element that appeared as a monad and by the presence of multiple short synaptic ribbons. These findings confirm that certain ON cone bipolar cells can provide ON input to amacrine and ganglion cells whose dendrites stratify in the OFF sublayer via axonal synapses. The monadic synapse with multiple ribbons may be a diagnostic feature of the ON cone bipolar axonal synapse in sublamina a. The presence of multiple ribbons and a broad postsynaptic density suggest these structures may be very efficient synapses. We also identified axonal inputs to ipRGCs with the architecture described above.

  5. Neumonitis por hipersensibilidad en la ciudad de México

    Directory of Open Access Journals (Sweden)

    Carrillo-Rodríguez José G.

    2000-01-01

    Full Text Available OBJETIVO: Determinar la asociación entre la zona urbana de origen del paciente en la ciudad de México y la prevalencia de neumonitis por hipersensibilidad inducida por antígeno aviario. MATERIAL Y MÉTODOS: Se trata de un estudio de casos y controles realizado en el Instituto Nacional de Enfermedades Respiratorias, en la ciudad de México, en el año de 1999. Se estudiaron 109 casos con neumonitis por hipersensibilidad y 184 controles: de éstos, 39, con fibrosis pulmonar idiopática; 63, con tuberculosis pulmonar, y 82, con asma. La ciudad de México y las zonas conurbadas se dividieron en cinco zonas geográficas: centro, noreste, sureste, noroeste y el suroeste. Se calcularon las prevalencias de las diferentes enfermedades por zona urbana de los pacientes que participaron en el estudio; como medida de asociación, se estimó la razón de momios, con un intervalo de confianza al 95%. Asimismo, se realizó regresión logística múltiple ajustando por edad, sexo y estrato socioeconómico. RESULTADOS: Ochenta casos de neumonitis por hipersensibilidad se concentraron en el sur del noreste de las zonas conurbadas y la parte norte del sureste de la ciudad de México, 48 y 32, respectivamente (RM= 3.86, IC 95% 2.17-6.96. Treinta y seis controles de asma se localizaron en el suroeste de la ciudad de México, zona donde se ubica el Intituto Nacional de Enfermedades Respiratorias (p<0.05 y cuatro en la zona conurbada. Los controles de tuberculosis pulmonar y fibrosis pulmonar idiopática estuvieron dispersos en la ciudad de México y en las zonas conurbadas. CONCLUSIONES: La zona sur del noreste y el norte de la sureste están asociadas a la neumonitis por hipersensibilidad. Las causas de esta asociación no parece ser geográfica, pero existe el antecedente de que esa zona fue basurero de la ciudad, por lo que partículas orgánicas en el ambiente pudieran coadyuvar a la aparición de esta enfermedad.

  6. Reparación endovascular de coartación de aorta con parada cardíaca inducida con adenosina

    Directory of Open Access Journals (Sweden)

    Ignacio José Rivera-Chavarría

    2014-09-01

    Full Text Available La coartación de aorta es un estrechamiento congénito de la luz aórtica que, generalmente, afecta la porción torácica distal a la emergencia de la arteria subclavia izquierda. Esta condición es de gran importancia, pues predispone al desarrollo de patologías cardiovasculares a edades tempranas, lo que se traduce en una alta morbimortalidad. Se reporta el primer caso en Costa Rica, de reparación endovascular de una coartación de aorta, mediante la colocación de un stent recubierto, con parada cardiaca inducida con adenosina. La paciente toleró el procedimiento bien y el gradiente postintervención fue menor de 5 mmHg. Su presión arterial sistémica es 100/60mmHg y no tiene limitaciones o sintomatología.

  7. Períodos perturbados: disipación de energía y corrientes geomagnéticas inducidas

    Directory of Open Access Journals (Sweden)

    Patricia A. Larocca

    2010-06-01

    Full Text Available Se estudia, en un evento típico (12-13 de junio de 2005 las energías entrante y disipada en la magnetosfera ( y Ut respectivamente y el aumento de corrientes inducidas en un gasoducto ubicado en altas latitudes. Se analizan para el período citado los índices geomagnéticos AE y Dst, y la componente Bz del campo geomagnético interplanetario como indicadores del desarrollo del período perturbado. Se calculan los tiempos de decaimiento del anillo de corriente utilizando distintas aproximaciones de acuerdo con las fases de la tormenta. Durante este período se observaron variaciones geomagnéticas importantes que originaron corrientes geomagnéticas inducidas significativas sobre el gasoducto de la empresa Transcanada ubicado en la zona del valle del río Ottawa; pudiendo ser afectada la vida útil del mismo.In a typical event (12-13 June 2005, solar wind energy rate and total energy dissipation rate in the magnetosphere (e and Ut respectively and increased induced currents in a gas pipe located in the auroral zone are studied. For the period geomagnetic indices AE and Dst, and the Bz component of the interplanetary geomagnetic field are analyzed as indicators of the development of the troubled period. Ring current decay times are calculated using different approaches in accordance with the phases of the storm. During this period there were significant geomagnetic variations due to geomagnetic substorms and induced currents on the pipeline located in the Otawa River Valley, this fact could produce corrosion increases in its structure.

  8. Myelinated sensory and alpha motor axon regeneration in peripheral nerve neuromas

    Science.gov (United States)

    Macias, M. Y.; Lehman, C. T.; Sanger, J. R.; Riley, D. A.

    1998-01-01

    Histochemical staining for carbonic anhydrase and cholinesterase (CE) activities was used to analyze sensory and motor axon regeneration, respectively, during neuroma formation in transected and tube-encapsulated peripheral nerves. Median-ulnar and sciatic nerves in the rodent model permitted testing whether a 4 cm greater distance of the motor neuron soma from axotomy site or intrinsic differences between motor and sensory neurons influenced regeneration and neuroma formation 10, 30, and 90 days later. Ventral root radiculotomy confirmed that CE-stained axons were 97% alpha motor axons. Distance significantly delayed axon regeneration. When distance was negligible, sensory axons grew out sooner than motor axons, but motor axons regenerated to a greater quantity. These results indicate regeneration differences between axon subtypes and suggest more extensive branching of motor axons within the neuroma. Thus, both distance from injury site to soma and inherent motor and sensory differences should be considered in peripheral nerve repair strategies.

  9. Schwann cell-derived exosomes enhance axonal regeneration in the peripheral nervous system.

    Science.gov (United States)

    Lopez-Verrilli, María Alejandra; Picou, Frederic; Court, Felipe A

    2013-11-01

    Axonal regeneration in the peripheral nervous system is greatly supported by Schwann cells (SCs). After nerve injury, SCs dedifferentiate to a progenitor-like state and efficiently guide axons to their original target tissues. Contact and soluble factors participate in the crosstalk between SCs and axons during axonal regeneration. Here we show that dedifferentiated SCs secrete nano-vesicles known as exosomes which are specifically internalized by axons. Surprisingly, SC-derived exosomes markedly increase axonal regeneration in vitro and enhance regeneration after sciatic nerve injury in vivo. Exosomes shift the growth cone morphology to a pro-regenerating phenotype and decrease the activity of the GTPase RhoA, involved in growth cone collapse and axon retraction. Altogether, our work identifies a novel mechanism by which SCs communicate with neighboring axons during regenerative processes. We propose that SC exosomes represent an important mechanism by which these cells locally support axonal maintenance and regeneration after nerve damage.

  10. Subtypes of GABAergic neurons project axons in the neocortex

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    Shigeyoshi Higo

    2009-11-01

    Full Text Available γ-aminobutyric acid (GABAergic neurons in the neocortex have been regarded as interneurons and speculated to modulate the activity of neurons locally. Recently, however, several experiments revealed that neuronal nitric oxide synthase (nNOS-positive GABAergic neurons project cortico-cortically with long axons. In this study, we illustrate Golgi-like images of the nNOS-positive GABAergic neurons using a nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d reaction and follow the emanating axon branches in cat brain sections. These axon branches projected cortico-cortically with other non-labeled arcuate fibers, contra-laterally via the corpus callosum and anterior commissure. The labeled fibers were not limited to the neocortex but found also in the fimbria of the hippocampus. In order to have additional information on these GABAergic neuron projections, we investigated green fluorescent protein (GFP-labeled GABAergic neurons in GAD67-Cre knock-in / GFP Cre-reporter mice. GFP-labeled axons emanate densely, especially in the fimbria, a small number in the anterior commissure, and very sparsely in the corpus callosum. These two different approaches confirm that not only nNOS-positive GABAergic neurons but also other subtypes of GABAergic neurons project long axons in the cerebral cortex and are in a position to be involved in information processing.

  11. A novel technique using hydrophilic polymers to promote axonal fusion

    Directory of Open Access Journals (Sweden)

    Ravinder Bamba

    2016-01-01

    Full Text Available The management of traumatic peripheral nerve injury remains a considerable concern for clinicians. With minimal innovations in surgical technique and a limited number of specialists trained to treat peripheral nerve injury, outcomes of surgical intervention have been unpredictable. The inability to manipulate the pathophysiology of nerve injury (i.e., Wallerian degeneration has left scientists and clinicians depending on the slow and lengthy process of axonal regeneration (~1 mm/day. When axons are severed, the endings undergo calcium-mediated plasmalemmal sealing, which limits the ability of the axon to be primarily repaired. Polythethylene glycol (PEG in combination with a bioengineered process overcomes the inability to fuse axons. The mechanism for PEG axonal fusion is not clearly understood, but multiple studies have shown that a providing a calcium-free environment is essential to the process known as PEG fusion. The proposed mechanism is PEG-induced lipid bilayer fusion by removing the hydration barrier surrounding the axolemma and reducing the activation energy required for membrane fusion to occur. This review highlights PEG fusion, its past and current studies, and future directions in PEG fusion.

  12. A novel technique using hydrophilic polymers to promote axonal fusion

    Institute of Scientific and Technical Information of China (English)

    Ravinder Bamba; D Colton Riley; Nathaniel D Kelm; Mark D Does; Richard D Dortch; Wesley P hTayer

    2016-01-01

    The management of traumatic peripheral nerve injury remains a considerable concern for clinicians. With minimal innovations in surgical technique and a limited number of specialists trained to treat peripheral nerve injury, outcomes of surgical intervention have been unpredictable. The inability to manipulate the pathophysiology of nerve injury (i.e., Wallerian degeneration) has left scientists and clinicians depending on the slow and lengthy process of axonal regeneration (~1 mm/day). When axons are severed, the endings undergo calcium-mediated plasmalemmal sealing, which limits the ability of the axon to be primarily re-paired. Polythethylene glycol (PEG) in combination with a bioengineered process overcomes the inability to fuse axons. The mechanism for PEG axonal fusion is not clearly understood, but multiple studies have shown that a providing a calcium-free environment is essential to the process known as PEG fusion. The proposed mechanism is PEG-induced lipid bilayer fusion by removing the hydration barrier surrounding the axolemma and reducing the activation energy required for membrane fusion to occur. This review highlights PEG fusion, its past and current studies, and future directions in PEG fusion.

  13. Calpain Inhibition Reduces Axolemmal Leakage in Traumatic Axonal Injury

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    János Sándor

    2009-12-01

    Full Text Available Calcium-induced, calpain-mediated proteolysis (CMSP has recently been implicated to the pathogenesis of diffuse (traumatic axonal injury (TAI. Some studies suggested that subaxolemmal CMSP may contribute to axolemmal permeability (AP alterations observed in TAI. Seeking direct evidence for this premise we investigated whether subaxolemmal CMSP may contribute to axolemmal permeability alterations (APA and pre-injury calpain-inhibition could reduce AP in a rat model of TAI. Horseradish peroxidase (HRP, a tracer that accumulates in axons with APA was administered one hour prior to injury into the lateral ventricle; 30 min preinjury a single tail vein bolus injection of 30 mg/kg MDL-28170 (a calpain inhibitor or its vehicle was applied in Wistar rats exposed to impact acceleration brain injury. Histological detection of traumatically injured axonal segments accumulating HRP and statistical analysis revealed that pre-injury administration of the calpain inhibitor MDL-28170 significantly reduced the average length of HRP-labeled axonal segments. The axono-protective effect of pre-injury calpain inhibition recently demonstrated with classical immunohistochemical markers of TAI was further corroborated in this experiment; significant reduction of the length of labeled axons in the drug-treated rats implicate CMSP in the progression of altered AP in TAI.

  14. Functional complexity of the axonal growth cone: a proteomic analysis.

    Directory of Open Access Journals (Sweden)

    Adriana Estrada-Bernal

    Full Text Available The growth cone, the tip of the emerging neurite, plays a crucial role in establishing the wiring of the developing nervous system. We performed an extensive proteomic analysis of axonal growth cones isolated from the brains of fetal Sprague-Dawley rats. Approximately 2000 proteins were identified at ≥ 99% confidence level. Using informatics, including functional annotation cluster and KEGG pathway analysis, we found great diversity of proteins involved in axonal pathfinding, cytoskeletal remodeling, vesicular traffic and carbohydrate metabolism, as expected. We also found a large and complex array of proteins involved in translation, protein folding, posttranslational processing, and proteasome/ubiquitination-dependent degradation. Immunofluorescence studies performed on hippocampal neurons in culture confirmed the presence in the axonal growth cone of proteins representative of these processes. These analyses also provide evidence for rough endoplasmic reticulum and reveal a reticular structure equipped with Golgi-like functions in the axonal growth cone. Furthermore, Western blot revealed the growth cone enrichment, relative to fetal brain homogenate, of some of the proteins involved in protein synthesis, folding and catabolism. Our study provides a resource for further research and amplifies the relatively recently developed concept that the axonal growth cone is equipped with proteins capable of performing a highly diverse range of functions.

  15. Neurofilament proteins in axonal regeneration and neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    Haitao Wang; Minfei Wu; Chuanjun Zhan; Enyuan Ma; Maoguang Yang; Xiaoyu Yang; Yingpu Li

    2012-01-01

    Neurofilament protein is a component of the mature neuronal cytoskeleton, and it interacts with the zygosome, which is mediated by neurofilament-related proteins. Neurofilament protein regulates enzyme function and the structure of linker proteins. In addition, neurofilament gene expression plays an important role in nervous system development. Previous studies have shown that neurofilament gene transcriptional regulation is crucial for neurofilament protein expression, especially in axonal regeneration and degenerative diseases. Post-transcriptional regulation increased neurofilament protein gene transcription during axonal regeneration, ultimately resulting in a pattern of neurofilament protein expression. An expression imbalance of post-transcriptional regulatory proteins and other disorders could lead to amyotrophic lateral sclerosis or other neurodegenerative diseases. These findings indicated that after transcription, neurofilament protein regulated expression of related proteins and promoted regeneration of damaged axons, suggesting that regulation disorders could lead to neurodegenerative diseases.

  16. Pili canaliculi as manifestation of giant axonal neuropathy*

    Science.gov (United States)

    de Almeida Jr., Hiram Larangeira; Garcias, Gilberto; Silva, Ricardo Marques e; Batista, Stela Laner; Pasetto, Fernanda

    2016-01-01

    Giant axonal neuropathy is a rare autosomal recessive neurodegenerative disease. The condition is characterized by neurons with abnormally large axons due to intracellular filament accumulation. The swollen axons affect both the peripheral and central nervous system. A 6-year old female patient had been referred to a geneticist reporting problems with walking and hypotonia. At the age of 10, she became wheelchair dependent. Scanning electron microscopy of a curly hair classified it as pili canaliculi. GAN gene sequencing demonstrated mutation c.1456G>A (p.GLU486LYS). At the age of 12, the patient died due to respiratory complications. Dermatologists should be aware of this entity since hair changes are considered suggestive of GAN.

  17. Using quantum filters to process images of diffuse axonal injury

    Science.gov (United States)

    Pineda Osorio, Mateo

    2014-06-01

    Some images corresponding to a diffuse axonal injury (DAI) are processed using several quantum filters such as Hermite Weibull and Morse. Diffuse axonal injury is a particular, common and severe case of traumatic brain injury (TBI). DAI involves global damage on microscopic scale of brain tissue and causes serious neurologic abnormalities. New imaging techniques provide excellent images showing cellular damages related to DAI. Said images can be processed with quantum filters, which accomplish high resolutions of dendritic and axonal structures both in normal and pathological state. Using the Laplacian operators from the new quantum filters, excellent edge detectors for neurofiber resolution are obtained. Image quantum processing of DAI images is made using computer algebra, specifically Maple. Quantum filter plugins construction is proposed as a future research line, which can incorporated to the ImageJ software package, making its use simpler for medical personnel.

  18. Uncovering sensory axonal dysfunction in asymptomatic type 2 diabetic neuropathy

    Science.gov (United States)

    Sung, Jia-Ying; Tani, Jowy; Chang, Tsui-San; Lin, Cindy Shin-Yi

    2017-01-01

    This study investigated sensory and motor nerve excitability properties to elucidate the development of diabetic neuropathy. A total of 109 type 2 diabetes patients were recruited, and 106 were analyzed. According to neuropathy severity, patients were categorized into G0, G1, and G2+3 groups using the total neuropathy score-reduced (TNSr). Patients in the G0 group were asymptomatic and had a TNSr score of 0. Sensory and motor nerve excitability data from diabetic patients were compared with data from 33 healthy controls. Clinical assessment, nerve conduction studies, and sensory and motor nerve excitability testing data were analyzed to determine axonal dysfunction in diabetic neuropathy. In the G0 group, sensory excitability testing revealed increased stimulus for the 50% sensory nerve action potential (P<0.05), shortened strength-duration time constant (P<0.01), increased superexcitability (P<0.01), decreased subexcitability (P<0.05), decreased accommodation to depolarizing current (P<0.01), and a trend of decreased accommodation to hyperpolarizing current in threshold electrotonus. All the changes progressed into G1 (TNSr 1–8) and G2+3 (TNSr 9–24) groups. In contrast, motor excitability only had significantly increased stimulus for the 50% compound motor nerve action potential (P<0.01) in the G0 group. This study revealed that the development of axonal dysfunction in sensory axons occurred prior to and in a different fashion from motor axons. Additionally, sensory nerve excitability tests can detect axonal dysfunction even in asymptomatic patients. These insights further our understanding of diabetic neuropathy and enable the early detection of sensory axonal abnormalities, which may provide a basis for neuroprotective therapeutic approaches. PMID:28182728

  19. Motoneuron axon pathfinding errors in zebrafish: Differential effects related to concentration and timing of nicotine exposure

    Energy Technology Data Exchange (ETDEWEB)

    Menelaou, Evdokia; Paul, Latoya T. [Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803 (United States); Perera, Surangi N. [Joseph J. Zilber School of Public Health, University of Wisconsin — Milwaukee, Milwaukee, WI 53205 (United States); Svoboda, Kurt R., E-mail: svobodak@uwm.edu [Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803 (United States); Joseph J. Zilber School of Public Health, University of Wisconsin — Milwaukee, Milwaukee, WI 53205 (United States)

    2015-04-01

    Nicotine exposure during embryonic stages of development can affect many neurodevelopmental processes. In the developing zebrafish, exposure to nicotine was reported to cause axonal pathfinding errors in the later born secondary motoneurons (SMNs). These alterations in SMN axon morphology coincided with muscle degeneration at high nicotine concentrations (15–30 μM). Previous work showed that the paralytic mutant zebrafish known as sofa potato exhibited nicotine-induced effects onto SMN axons at these high concentrations but in the absence of any muscle deficits, indicating that pathfinding errors could occur independent of muscle effects. In this study, we used varying concentrations of nicotine at different developmental windows of exposure to specifically isolate its effects onto subpopulations of motoneuron axons. We found that nicotine exposure can affect SMN axon morphology in a dose-dependent manner. At low concentrations of nicotine, SMN axons exhibited pathfinding errors, in the absence of any nicotine-induced muscle abnormalities. Moreover, the nicotine exposure paradigms used affected the 3 subpopulations of SMN axons differently, but the dorsal projecting SMN axons were primarily affected. We then identified morphologically distinct pathfinding errors that best described the nicotine-induced effects on dorsal projecting SMN axons. To test whether SMN pathfinding was potentially influenced by alterations in the early born primary motoneuron (PMN), we performed dual labeling studies, where both PMN and SMN axons were simultaneously labeled with antibodies. We show that only a subset of the SMN axon pathfinding errors coincided with abnormal PMN axonal targeting in nicotine-exposed zebrafish. We conclude that nicotine exposure can exert differential effects depending on the levels of nicotine and developmental exposure window. - Highlights: • Embryonic nicotine exposure can specifically affect secondary motoneuron axons in a dose-dependent manner.

  20. Giant Axonal Neuropathy Among Two Siblings - A Case Report

    Directory of Open Access Journals (Sweden)

    John Jhon. K

    2001-01-01

    Full Text Available Giant axonal neuropathy is a rate disorder with an autosomal recessive inheritance. It should be differentiated from toxic neuropathies, and hereditary degenerative disorders of nervous system like Friedreich′s ataxia and HMSN. Thick curly hair, though may not be present always is a useful clinical clue to identify cases. Prognosis is generally poor though course of the illness is variable. We report here a clinically and hisopathologically characteristic familial case of giant axonal neuropathy, which occurred in a 17-year-old boy, and his 21-year-old sister.

  1. Regulation of Axonal Midline Guidance by Prolyl 4-Hydroxylation in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Torpe, Nanna; Pocock, Roger David John

    2014-01-01

    Neuronal wiring during development requires that the growth cones of axons and dendrites are correctly guided to their appropriate targets. As in other animals, axon growth cones in Caenorhabditis elegans integrate information in their extracellular environment via interactions among transiently...

  2. Rapid axonal transport in primate optic nerve. Distribution of pressure-induced interruption.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1981-04-01

    Six primate eyes were studied after four hours of elevated intraocular pressure. Tissue specimens from the region of the lamina cribrosa were examined in cross section by transmission electron microscopy. Interruption in fast orthograde and retrograde axonal transport was identified in individual axons by noting accumulation of membraneous microorganelles, such as mitochondria and microvesicles within axon cylinders. Although organelle accumulation varied from bundle to bundle, involvement of individual axons was diffuse across the extent of a specific axon bundle. This observation contradicts the apparent association of axonal transport block with crosswise-oriented trabecular beams at the level of the lamina cribrosa as seen in tissue specimens examined in longitudinal section. It also fails to support the notion that blocked axonal transport with elevated pressure is produced by kinking of axons at the lamina.

  3. Axon diameter and intra-axonal volume fraction of the corticospinal tract in idiopathic normal pressure hydrocephalus measured by q-space imaging.

    Directory of Open Access Journals (Sweden)

    Kouhei Kamiya

    Full Text Available PURPOSE: Previous studies suggest that compression and stretching of the corticospinal tract (CST potentially cause treatable gait disturbance in patients with idiopathic normal pressure hydrocephalus (iNPH. Measurement of axon diameter with diffusion MRI has recently been used to investigate microstructural alterations in neurological diseases. In this study, we investigated alterations in the axon diameter and intra-axonal fraction of the CST in iNPH by q-space imaging (QSI analysis. METHODS: Nineteen patients with iNPH and 10 age-matched controls were recruited. QSI data were obtained with a 3-T system by using a single-shot echo planar imaging sequence with the diffusion gradient applied parallel to the antero-posterior axis. By using a two-component low-q fit model, the root mean square displacements of intra-axonal space ( =  axon diameter and intra-axonal volume fraction of the CST were calculated at the levels of the internal capsule and body of the lateral ventricle, respectively. RESULTS: Wilcoxon's rank-sum test revealed a significant increase in CST intra-axonal volume fraction at the paraventricular level in patients (p<0.001, whereas no significant difference was observed in the axon diameter. At the level of the internal capsule, neither axon diameter nor intra-axonal volume fraction differed significantly between the two groups. CONCLUSION: Our results suggest that in patients with iNPH, the CST does not undergo irreversible axonal damage but is rather compressed and/or stretched owing to pressure from the enlarged ventricle. These analyses of axon diameter and intra-axonal fraction yield insights into microstructural alterations of the CST in iNPH.

  4. Computational Analysis of Axonal Transport: A Novel Assessment of Neurotoxicity, Neuronal Development and Functions

    Directory of Open Access Journals (Sweden)

    Toshiyuki Gotoh

    2012-03-01

    Full Text Available Axonal transport plays a crucial role in neuronal morphogenesis, survival and function. Despite its importance, however, the molecular mechanisms of axonal transport remain mostly unknown because a simple and quantitative assay system for monitoring this cellular process has been lacking. In order to better characterize the mechanisms involved in axonal transport, we formulate a novel computer-assisted monitoring system of axonal transport. Potential uses of this system and implications for future studies will be discussed.

  5. Ensayo piloto de biorremediación de suelos contaminados por hidrocarburos. Fase ll

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    Gloria Lucía Camargo Millán

    2009-06-01

    Full Text Available  El estudio de la biodegradación de los hidrocarburos compuestos,altamente contaminantes y tóxicos, es de interéspara la descontaminación de ambientes afectados por derramesde petróleo. Aunque este proceso se presenta demanera natural, es demasiado lento, razón por la que sehace necesario el uso de técnicas de biorremediación parafacilitar la acción microbiana sobre los contaminantes. Anivel experimental este proceso se realiza por etapas o ensayos,ya sean de laboratorio, pilotos, de campo oimplementación. Previamente a este estudio se trabajó unaetapa a nivel de laboratorio, donde se observó la remociónde hidrocarburo en un suelo contaminado de manera inducida,aislándose bacterias capaces de su degradación, loque mostró que el proceso es factible. El presente estudiocorresponde a la etapa a nivel piloto, cuyo objetivo eracuantificar la tasa de remoción de hidrocarburo en muestrasde suelo contaminadas con crudo de castilla provenientede diez terrarios, a los cuales se les inoculó bacteriastotales y bacterias Pseudomonas aeruginosa.

  6. IFNgamma enhances microglial reactions to hippocampal axonal degeneration

    DEFF Research Database (Denmark)

    Jensen, M B; Hegelund, I V; Lomholt, N D;

    2000-01-01

    periods. Message for the immune cytokine interferon-gamma (IFNgamma) was undetectable, and glial reactivity to axonal lesions occurred as normal in IFNgamma-deficient mice. Microglial responses to lesion-induced neuronal injury were markedly enhanced in myelin basic protein promoter-driven transgenic mice...

  7. PTEN inhibition and axon regeneration and neural repair

    Institute of Scientific and Technical Information of China (English)

    Yosuke Ohtake; Umar Hayat; Shuxin Li

    2015-01-01

    The intrinsic growth ability of all the neurons declines during development although some may grow better than others. Numerous intracellular signaling proteins and transcription factors have been shown to regulate the intrinsic growth capacity in mature neurons. Among them, PI3 kinase/Akt pathway is important for controlling axon elongation. As a negative regulator of this pathway, the tumor suppressor phosphatase and tensin homolog (PTEN) appears critical to con-trol the regenerative ability of young and adult neurons. This review will focus on recent research progress in axon regeneration and neural repair by PTEN inhibition and therapeutic potential of blocking this phosphatase for neurological disorders. Inhibition of PTEN by deletion in con-ditional knockout mice, knockdown by short-hairpin RNA, or blockade by pharmacological approaches, including administration of selective PTEN antagonist peptides, stimulates various degrees of axon regrowth in juvenile or adult rodents with central nervous system injuries. Im-portantly, post-injury PTEN suppression could enhance axonal growth and functional recovery in adult central nervous system after injury.

  8. Life-or-death decisions upon axonal damage.

    Science.gov (United States)

    Roselli, Francesco; Caroni, Pico

    2012-02-01

    In this issue of Neuron, Hu et al. (2012) report that upon axonal damage, CHOP and XBP1 unfolded protein response pathways are not recruited equally and have opposite effects on neuronal survival. XBP1 pathway boosting may represent a valuable neuroprotective strategy.

  9. Drosophila Ryks and their roles in axon and muscle guidance

    NARCIS (Netherlands)

    Lahaye, Liza Lucia

    2015-01-01

    In the last decade it has become clear that a number of the molecular mechanisms that are required for proper navigation of axons in complex nervous systems are also employed to guide muscles to their appropriate attachment sites. Among the gene families that mediate these diverse processes is the R

  10. Quantifying mechanical force in axonal growth and guidance

    Directory of Open Access Journals (Sweden)

    Ahmad Ibrahim Mahmoud Athamneh

    2015-09-01

    Full Text Available Mechanical force plays a fundamental role in neuronal development, physiology, and regeneration. In particular, research has shown that force is involved in growth cone-mediated axonal growth and guidance as well as stretch-induced elongation when an organism increases in size after forming initial synaptic connections. However, much of the details about the exact role of force in these fundamental processes remain unknown. In this review, we highlight (1 standing questions concerning the role of mechanical force in axonal growth and guidance and (2 different experimental techniques used to quantify forces in axons and growth cones. We believe that satisfying answers to these questions will require quantitative information about the relationship between elongation, forces, cytoskeletal dynamics, axonal transport, signaling, substrate adhesion, and stiffness contributing to directional growth advance. Furthermore, we address why a wide range of force values have been reported in the literature, and what these values mean in the context of neuronal mechanics. We hope that this review will provide a guide for those interested in studying the role of force in development and regeneration of neuronal networks.

  11. Traction Force and Tension Fluctuations During Axon Growth

    Directory of Open Access Journals (Sweden)

    Jamison ePolackwich

    2015-10-01

    Full Text Available Actively generated mechanical forces play a central role in axon growthand guidance, but the mechanisms that underly force generation andregulation in growing axons remain poorly understood. We reportmeasurements of the dynamics of traction stresses from growth cones ofactively advancing axons from postnatal rat DRG neurons. By tracking themovement of the growth cone and analyzing the traction stress field froma reference frame that moves with it, we are able to show that there isa clear and consistent average stress field that underlies the complexspatial stresses present at any one time. The average stress field hasstrong maxima on the sides of the growth cone, directed inward towardthe growth cone neck. This pattern represents a contractile stresscontained within the growth cone, and a net force that is balanced bythe axon tension. Using high time-resolution measurements of the growthcone traction stresses, we show that the stress field is composed offluctuating local stress peaks, with a large number peaks that live fora short time, a population of peaks whose lifetime distribution followsan exponential decay, and a small number of very long-lived peaks. Weshow that the high time-resolution data also reveal that the tensionappears to vary randomly over short time scales, roughly consistent withthe lifetime of the stress peaks, suggesting that the tensionfluctuations originate from stochastic adhesion dynamics.

  12. Unravelling the incidence and etiology of chronic idiopathic axonal polyneuropathy

    NARCIS (Netherlands)

    Visser, N.A.

    2016-01-01

    Chronic idiopathic axonal polyneuropathy (CIAP) is a sensory or sensorimotor polyneuropathy that has a slowly progressive course without severe disability. CIAP is diagnosed in a significant proportion of patients with polyneuropathy, but precise figures on the incidence of polyneuropathy and CIAP w

  13. Axon diameter mapping in crossing fibers with diffusion MRI

    DEFF Research Database (Denmark)

    Zhang, Hui; Dyrby, Tim B; Alexander, Daniel C

    2011-01-01

    This paper proposes a technique for a previously unaddressed problem, namely, mapping axon diameter in crossing fiber regions, using diffusion MRI. Direct measurement of tissue microstructure of this kind using diffusion MRI offers a new class of biomarkers that give more specific information abo...

  14. Axonal dynamics of excitatory and inhibitory neurons in somatosensory cortex.

    Directory of Open Access Journals (Sweden)

    Sally A Marik

    Full Text Available Cortical topography can be remapped as a consequence of sensory deprivation, suggesting that cortical circuits are continually modified by experience. To see the effect of altered sensory experience on specific components of cortical circuits, we imaged neurons, labeled with a genetically modified adeno-associated virus, in the intact mouse somatosensory cortex before and after whisker plucking. Following whisker plucking we observed massive and rapid reorganization of the axons of both excitatory and inhibitory neurons, accompanied by a transient increase in bouton density. For horizontally projecting axons of excitatory neurons there was a net increase in axonal projections from the non-deprived whisker barrel columns into the deprived barrel columns. The axon collaterals of inhibitory neurons located in the deprived whisker barrel columns retracted in the vicinity of their somata and sprouted long-range projections beyond their normal reach towards the non-deprived whisker barrel columns. These results suggest that alterations in the balance of excitation and inhibition in deprived and non-deprived barrel columns underlie the topographic remapping associated with sensory deprivation.

  15. Chronic excitotoxin-induced axon degeneration in a compartmented neuronal culture model

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    Katherine A Hosie

    2012-02-01

    Full Text Available Glutamate excitotoxicity is a major pathogenic process implicated in many neurodegenerative conditions, including AD (Alzheimer's disease and following traumatic brain injury. Occurring predominantly from over-stimulation of ionotropic glutamate receptors located along dendrites, excitotoxic axonal degeneration may also occur in white matter tracts. Recent identification of axonal glutamate receptor subunits within axonal nanocomplexes raises the possibility of direct excitotoxic effects on axons. Individual neuronal responses to excitotoxicity are highly dependent on the complement of glutamate receptors expressed by the cell, and the localization of the functional receptors. To enable isolation of distal axons and targeted excitotoxicity, murine cortical neuron cultures were prepared in compartmented microfluidic devices, such that distal axons were isolated from neuronal cell bodies. Within the compartmented culture system, cortical neurons developed to relative maturity at 11 DIV (days in vitro as demonstrated by the formation of dendritic spines and clustering of the presynaptic protein synaptophysin. The isolated distal axons retained growth cone structures in the absence of synaptic targets, and expressed glutamate receptor subunits. Glutamate treatment (100 μM to the cell body chamber resulted in widespread degeneration within this chamber and degeneration of distal axons in the other chamber. Glutamate application to the distal axon chamber triggered a lesser degree of axonal degeneration without degenerative changes in the untreated somal chamber. These data indicate that in addition to current mechanisms of indirect axonal excitotoxicity, the distal axon may be a primary target for excitotoxicity in neurodegenerative conditions.

  16. Differential Axonal Projection of Mitral and Tufted Cells in the Mouse Main Olfactory System

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    Shin Nagayama

    2010-09-01

    Full Text Available In the past decade, much has been elucidated regarding the functional organization of the axonal connection of olfactory sensory neurons to olfactory bulb (OB glomeruli. However, the manner in which projection neurons of the OB process odorant input and send this information to higher brain centers remains unclear. Here, we report long-range, large-scale tracing of the axonal projection patterns of OB neurons using two-photon microscopy. Tracer injection into a single glomerulus demonstrated widely distributed mitral/tufted cell axonal projections on the lateroventral surface of the mouse brain, including the anterior/posterior piriform cortex (PC and olfactory tubercle (OT. We noted two distinct groups of labeled axons: PC-orienting axons and OT-orienting axons. Each group occupied distinct parts of the lateral olfactory tract. PC-orienting axons projected axon collaterals to a wide area of the PC but only a few collaterals to the OT. OT-orienting axons densely projected axon collaterals primarily to the anterolateral OT (alOT. Different colored dye injections into the superficial and deep portions of the OB external plexiform layer revealed that the PC-orienting axon populations originated in presumed mitral cells and the OT-orienting axons in presumed tufted cells. These data suggest that although mitral and tufted cells receive similar odor signals from a shared glomerulus, they process the odor information in different ways and send their output to different higher brain centers via the PC and alOT.

  17. Wnt-induced calcium signaling mediates axon growth and guidance in the developing corpus callosum.

    Science.gov (United States)

    Hutchins, B Ian; Li, Li; Kalil, Katherine

    2012-01-10

    Wnt5a gradients guide callosal axons by repulsion through Ryk receptors in vivo. We recently found that Wnt5a repels cortical axons and promotes axon outgrowth through calcium signaling in vitro. Here, using cortical slices, we show that Wnt5a signals through Ryk to guide and promote outgrowth of callosal axons after they cross the midline. Calcium transient frequencies in callosal growth cones positively correlate with axon outgrowth rates in vitro. In cortical slices, calcium release through inositol 1,4,5-trisphosphate (IP(3)) receptors and calcium entry through transient receptor potential channels modulate axon growth and guidance. Knocking down Ryk inhibits calcium signaling in cortical axons, reduces rates of axon outgrowth subsequent to midline crossing, and causes axon guidance defects. Calcium- and calmodulin-dependent protein kinase II (CaMKII) is required downstream of Wnt-induced calcium signaling for postcrossing callosal axon growth and guidance. Taken together, these results suggest that growth and guidance of postcrossing callosal axons by Wnt-Ryk-calcium signaling involves axon repulsion through CaMKII.

  18. Nicotine elicits prolonged calcium signaling along ventral hippocampal axons.

    Science.gov (United States)

    Zhong, Chongbo; Talmage, David A; Role, Lorna W

    2013-01-01

    Presynaptic nicotinic acetylcholine receptors (nAChRs) have long been implicated in the modulation of CNS circuits. We previously reported that brief exposure to low concentrations of nicotine induced sustained potentiation of glutamatergic transmission at ventral hippocampal (vHipp)-striatal synapses. Here, we exploited nAChR subtype-selective antagonists and agonists and α7*nAChR knockout mutant mice (α7-/-) to elucidate the signaling mechanisms underlying nAChR-mediated modulation of synaptic transmission. Using a combination of micro-slices culture from WT and α7-/-mice, calcium imaging, and immuno-histochemical techniques, we found that nicotine elicits localized and oscillatory increases in intracellular Ca(2+) along vHipp axons that persists for up to 30 minutes. The sustained phase of the nicotine-induced Ca(2+) response was blocked by α-BgTx but not by DHβE and was mimicked by α7*nAChR agonists but not by non-α7*nAChR agonists. In vHipp slices from α7-/- mice, nicotine elicited only transient increases of axonal Ca(2+) signals and did not activate CaMKII. The sustained phase of the nicotine-induced Ca(2+) response required localized activation of CaMKII, phospholipase C, and IP3 receptor mediated Ca(2+)-induced Ca(2+) release (CICR). In conclusion, activation of presynaptic nAChRs by nicotine elicits Ca(2+) influx into the presynaptic axons, the sustained phase of the nicotine-induced Ca(2+) response requires that axonal α7*nAChR activate a downstream signaling network in the vHipp axons.

  19. The proliferation induced by hyperthermia in NB69 cells is offset by a radar-like signal; La proliferacion inducida por hipertermia en celulas NB69 es contrarrestada por una senal de tipo radar

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    Trillo Ruiz, M. A.; Martinez Pascual, M. A.; Cid Torres, M. A.; Pague de la Vega, J. E.; Chacon Vargas, L.; Ubeda Maeso, A.

    2011-07-01

    The present study describes the proliferative response of the cell line NB69 human neuroblastoma, the simultaneous exposure to two physical agents: mild hyperthermia (+1 degree centigrade) and a pulsed signal RFsubthermal.

  20. Axonal action-potential initiation and Na+ channel densities in the soma and axon initial segment of subicular pyramidal neurons.

    Science.gov (United States)

    Colbert, C M; Johnston, D

    1996-11-01

    A long-standing hypothesis is that action potentials initiate first in the axon hillock/initial segment (AH-IS) region because of a locally high density of Na+ channels. We tested this idea in subicular pyramidal neurons by using patch-clamp recordings in hippocampal slices. Simultaneous recordings from the soma and IS confirmed that orthodromic action potentials initiated in the axon and then invaded the soma. However, blocking Na+ channels in the AH-IS with locally applied tetrodotoxin (TTX) did not raise the somatic threshold membrane potential for orthodromic spikes. TTX applied to the axon beyond the AH-IS (30-60 microm from the soma) raised the apparent somatic threshold by approximately 8 mV. We estimated the Na+ current density in the AH-IS and somatic membranes by using cell-attached patch-clamp recordings and found similar magnitudes (3-4 pA/microm2). Thus, the present results suggest that orthodromic action potentials initiate in the axon beyond the AH-IS and that the minimum threshold for spike initiation of the neuron is not determined by a high density of Na+ channels in the AH-IS region.

  1. ALS Along the Axons – Expression of Coding and Noncoding RNA Differs in Axons of ALS models

    Science.gov (United States)

    Rotem, Nimrod; Magen, Iddo; Ionescu, Ariel; Gershoni-Emek, Noga; Altman, Topaz; Costa, Christopher J.; Gradus, Tal; Pasmanik-Chor, Metsada; Willis, Dianna E.; Ben-Dov, Iddo Z.; Hornstein, Eran; Perlson, Eran

    2017-01-01

    Amyotrophic lateral sclerosis (ALS) is a multifactorial lethal motor neuron disease with no known treatment. Although the basic mechanism of its degenerative pathogenesis remains poorly understood, a subcellular spatial alteration in RNA metabolism is thought to play a key role. The nature of these RNAs remains elusive, and a comprehensive characterization of the axonal RNAs involved in maintaining neuronal health has yet to be described. Here, using cultured spinal cord (SC) neurons grown using a compartmented platform followed by next-generation sequencing (NGS) technology, we find that RNA expression differs between the somatic and axonal compartments of the neuron, for both mRNA and microRNA (miRNA). Further, the introduction of SOD1G93A and TDP43A315T, established ALS-related mutations, changed the subcellular expression and localization of RNAs within the neurons, showing a spatial specificity to either the soma or the axon. Altogether, we provide here the first combined inclusive profile of mRNA and miRNA expression in two ALS models at the subcellular level. These data provide an important resource for studies on the roles of local protein synthesis and axon degeneration in ALS and can serve as a possible target pool for ALS treatment. PMID:28300211

  2. Influence of the surgical manipulation of the colon in colonic induced carcinogenesis in rats Influencia de la manipulación quirúrgica del colon en la carcinogénesis cólica inducida en ratas

    Directory of Open Access Journals (Sweden)

    J. F. Noguera Aguilar

    2004-05-01

    1-2 dimetilhidrazina dihidrocloruro. Se identificaron los adenocarcinomas cólicos y se determinaron número de tumores, superficie tumoral y porcentaje de superficie tumoral. El análisis estadístico se realizó con modelos Anova de comparación de medias y con tablas de contingencia Chi cuadrado. Resultados: el número de tumores fue mayor en el grupo quirúrgico que en el control, apareciendo preferentemente alrededor del colon manipulado. La superficie y el porcentaje tumorales fueron mayores en el grupo quirúrgico que en el control, siendo mayores a su vez en el grupo con anastomosis frente al grupo con traumatismo cólico. Dentro de los grupos con anastomosis, presentó mayor superficie y porcentaje tumoral el grupo con adición de titanio frente al grupo con material reabsorbible. Conclusiones: la manipulación experimental del colon de la rata aumenta la carcinogénesis cólica farmacológicamente inducida. La creación de una anastomosis provoca un mayor incremento del proceso carcinogénico que la anastomosis simulada. Este proceso se ve además favorecido por la cantidad de material de sutura incluida en la anastomosis y por la naturaleza irreabsorbible de los materiales implantados en la línea anastomótica.

  3. Adult onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) and Nasu-Hakola disease: lesion staging and dynamic changes of axons and microglial subsets.

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    Oyanagi, Kiyomitsu; Kinoshita, Michiaki; Suzuki-Kouyama, Emi; Inoue, Teruhiko; Nakahara, Asa; Tokiwai, Mika; Arai, Nobutaka; Satoh, Jun-Ichi; Aoki, Naoya; Jinnai, Kenji; Yazawa, Ikuru; Arai, Kimihito; Ishihara, Kenji; Kawamura, Mitsuru; Ishizawa, Keisuke; Hasegawa, Kazuko; Yagisita, Saburo; Amano, Naoji; Yoshida, Kunihiro; Terada, Seishi; Yoshida, Mari; Akiyama, Haruhiko; Mitsuyama, Yoshio; Ikeda, Shu-Ichi

    2016-09-08

    The brains of 10 Japanese patients with adult onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) encompassing hereditary diffuse leukoencephalopathy with axonal spheroids (HDLS) and pigmentary orthochromatic leukodystrophy (POLD) and eight Japanese patients with Nasu-Hakola disease (N-HD) and five age-matched Japanese controls were examined neuropathologically with special reference to lesion staging and dynamic changes of microglial subsets. In both diseases, the pathognomonic neuropathological features included spherically swollen axons (spheroids and globules), axon loss and changes of microglia in the white matter. In ALSP, four lesion stages based on the degree of axon loss were discernible: Stage I, patchy axon loss in the cerebral white matter without atrophy; Stage II, large patchy areas of axon loss with slight atrophy of the cerebral white matter and slight dilatation of the lateral ventricles; Stage III, extensive axon loss in the cerebral white matter and dilatation of the lateral and third ventricles without remarkable axon loss in the brainstem and cerebellum; Stage IV, devastated cerebral white matter with marked dilatation of the ventricles and axon loss in the brainstem and/or cerebellum. Internal capsule and pontine base were relatively well preserved in the N-HD, even at Stage IV, and the swollen axons were larger with a higher density in the ALSP. Microglial cells immunopositive for CD68, CD163 or CD204 were far more obvious in ALSP, than in N-HD, and the shape and density of the cells changed in each stage. With progression of the stage, clinical symptoms became worse to apathetic state, and epilepsy was frequently observed in patients at Stages III and IV in both diseases. From these findings, it is concluded that (i) shape, density and subsets of microglia change dynamically along the passage of stages and (ii) increase of IBA-1-, CD68-, CD163- and CD204-immunopositive cells precedes loss of axons in ALSP.

  4. IH activity is increased in populations of slow versus fast motor axons of the rat.

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    Chad eLorenz

    2014-09-01

    Full Text Available Much is known about the electrophysiological variation in motoneuron somata across different motor units. However comparatively less is known about electrophysiological variation in motor axons and how this could impact function or electrodiagnosis in healthy or diseased states. We performed nerve excitability testing on two groups of motor axons in Sprague-Dawley rats that are known to differ significantly in their chronic daily activity patterns and in the relative proportion of motor unit types: one group innervating the soleus (slow motor axons and the other group innervating the tibialis anterior (fast motor axons muscles. We found that slow motor axons have significantly larger accommodation compared to fast motor axons upon application of a 100 ms hyperpolarizing conditioning stimulus that is 40% of axon threshold (Z = 3.24, p = 0.001 or 20% of axon threshold (Z = 2.67, p = 0.008. Slow motor axons had larger accommodation to hyperpolarizing currents in the current-threshold measurement (-80% Z = 3.07, p = 0.002; -90% Z = 2.98, p = 0.003. In addition, we found that slow motor axons have a significantly smaller rheobase than fast motor axons (Z = -1.99, p = 0.047 accompanied by a lower threshold in stimulus-response curves. The results provide evidence that slow motor axons have greater activity of the hyperpolarization-activated inwardly rectifying cation conductance (IH than fast motor axons. It is possible that this difference between fast and slow axons is caused by an adaptation to their chronic differences in daily activity patterns, and that this adaptation might have a functional effect on the motor unit. Moreover, these findings indicate that slow and fast motor axons may react differently to pathological conditions.

  5. Changes in microtubule stability and density in myelin-deficient shiverer mouse CNS axons

    Science.gov (United States)

    Kirkpatrick, L. L.; Witt, A. S.; Payne, H. R.; Shine, H. D.; Brady, S. T.

    2001-01-01

    Altered axon-Schwann cell interactions in PNS myelin-deficient Trembler mice result in changed axonal transport rates, neurofilament and microtubule-associated protein phosphorylation, neurofilament density, and microtubule stability. To determine whether PNS and CNS myelination have equivalent effects on axons, neurofilaments, and microtubules in CNS, myelin-deficient shiverer axons were examined. The genetic defect in shiverer is a deletion in the myelin basic protein (MBP) gene, an essential component of CNS myelin. As a result, shiverer mice have little or no compact CNS myelin. Slow axonal transport rates in shiverer CNS axons were significantly increased, in contrast to the slowing in demyelinated PNS nerves. Even more striking were substantial changes in the composition and properties of microtubules in shiverer CNS axons. The density of axonal microtubules is increased, reflecting increased expression of tubulin in shiverer, and the stability of microtubules is drastically reduced in shiverer axons. Shiverer transgenic mice with two copies of a wild-type myelin basic protein transgene have an intermediate level of compact myelin, making it possible to determine whether the actual level of compact myelin is an important regulator of axonal microtubules. Both increased microtubule density and reduced microtubule stability were still observed in transgenic mouse nerves, indicating that signals beyond synaptogenesis and the mere presence of compact myelin are required for normal regulation of the axonal microtubule cytoskeleton.

  6. The importance of axonal undulation in diffusion MR measurements: a Monte Carlo simulation study.

    Science.gov (United States)

    Nilsson, Markus; Lätt, Jimmy; Ståhlberg, Freddy; van Westen, Danielle; Hagslätt, Håkan

    2012-05-01

    Many axons follow wave-like undulating courses. This is a general feature of extracranial nerve segments, but is also found in some intracranial nervous tissue. The importance of axonal undulation has previously been considered, for example, in the context of biomechanics, where it has been shown that posture affects undulation properties. However, the importance of axonal undulation in the context of diffusion MR measurements has not been investigated. Using an analytical model and Monte Carlo simulations of water diffusion, this study compared undulating and straight axons in terms of diffusion propagators, diffusion-weighted signal intensities and parameters derived from diffusion tensor imaging, such as the mean diffusivity (MD), the eigenvalues and the fractional anisotropy (FA). All parameters were strongly affected by the presence of undulation. The diffusivity perpendicular to the undulating axons increased with the undulation amplitude, thus resembling that of straight axons with larger diameters. Consequently, models assuming straight axons for the estimation of the axon diameter from diffusion MR measurements might overestimate the diameter if undulation is present. FA decreased from approximately 0.7 to 0.5 when axonal undulation was introduced into the simulation model structure. Our results indicate that axonal undulation may play a role in diffusion measurements when investigating, for example, the optic and sciatic nerves and the spinal cord. The simulations also demonstrate that the stretching or compression of neuronal tissue comprising undulating axons alters the observed water diffusivity, suggesting that posture may be of importance for the outcome of diffusion MRI measurements.

  7. Neuroinflammation by cytotoxic T-lymphocytes impairs retrograde axonal transport in an oligodendrocyte mutant mouse.

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    Chi Wang Ip

    Full Text Available Mice overexpressing proteolipid protein (PLP develop a leukodystrophy-like disease involving cytotoxic, CD8+ T-lymphocytes. Here we show that these cytotoxic T-lymphocytes perturb retrograde axonal transport. Using fluorogold stereotactically injected into the colliculus superior, we found that PLP overexpression in oligodendrocytes led to significantly reduced retrograde axonal transport in retina ganglion cell axons. We also observed an accumulation of mitochondria in the juxtaparanodal axonal swellings, indicative for a disturbed axonal transport. PLP overexpression in the absence of T-lymphocytes rescued retrograde axonal transport defects and abolished axonal swellings. Bone marrow transfer from wildtype mice, but not from perforin- or granzyme B-deficient mutants, into lymphocyte-deficient PLP mutant mice led again to impaired axonal transport and the formation of axonal swellings, which are predominantly located at the juxtaparanodal region. This demonstrates that the adaptive immune system, including cytotoxic T-lymphocytes which release perforin and granzyme B, are necessary to perturb axonal integrity in the PLP-transgenic disease model. Based on our observations, so far not attended molecular and cellular players belonging to the immune system should be considered to understand pathogenesis in inherited myelin disorders with progressive axonal damage.

  8. Eph:ephrin-B1 forward signaling controls fasciculation of sensory and motor axons.

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    Luxey, Maëva; Jungas, Thomas; Laussu, Julien; Audouard, Christophe; Garces, Alain; Davy, Alice

    2013-11-15

    Axon fasciculation is one of the processes controlling topographic innervation during embryonic development. While axon guidance steers extending axons in the accurate direction, axon fasciculation allows sets of co-extending axons to grow in tight bundles. The Eph:ephrin family has been involved both in axon guidance and fasciculation, yet it remains unclear how these two distinct types of responses are elicited. Herein we have characterized the role of ephrin-B1, a member of the ephrinB family in sensory and motor innervation of the limb. We show that ephrin-B1 is expressed in sensory axons and in the limb bud mesenchyme while EphB2 is expressed in motor and sensory axons. Loss of ephrin-B1 had no impact on the accurate dorso-ventral innervation of the limb by motor axons, yet EfnB1 mutants exhibited decreased fasciculation of peripheral motor and sensory nerves. Using tissue-specific excision of EfnB1 and in vitro experiments, we demonstrate that ephrin-B1 controls fasciculation of axons via a surround repulsion mechanism involving growth cone collapse of EphB2-expressing axons. Altogether, our results highlight the complex role of Eph:ephrin signaling in the development of the sensory-motor circuit innervating the limb.

  9. The corpus callosum in primates: processing speed of axons and the evolution of hemispheric asymmetry

    Science.gov (United States)

    Phillips, Kimberley A.; Stimpson, Cheryl D.; Smaers, Jeroen B.; Raghanti, Mary Ann; Jacobs, Bob; Popratiloff, Anastas; Hof, Patrick R.; Sherwood, Chet C.

    2015-01-01

    Interhemispheric communication may be constrained as brain size increases because of transmission delays in action potentials over the length of axons. Although one might expect larger brains to have progressively thicker axons to compensate, spatial packing is a limiting factor. Axon size distributions within the primate corpus callosum (CC) may provide insights into how these demands affect conduction velocity. We used electron microscopy to explore phylogenetic variation in myelinated axon density and diameter of the CC from 14 different anthropoid primate species, including humans. The majority of axons were less than 1 µm in diameter across all species, indicating that conduction velocity for most interhemispheric communication is relatively constant regardless of brain size. The largest axons within the upper 95th percentile scaled with a progressively higher exponent than the median axons towards the posterior region of the CC. While brain mass among the primates in our analysis varied by 97-fold, estimates of the fastest cross-brain conduction times, as conveyed by axons at the 95th percentile, varied within a relatively narrow range between 3 and 9 ms across species, whereas cross-brain conduction times for the median axon diameters differed more substantially between 11 and 38 ms. Nonetheless, for both size classes of axons, an increase in diameter does not entirely compensate for the delay in interhemispheric transmission time that accompanies larger brain size. Such biophysical constraints on the processing speed of axons conveyed by the CC may play an important role in the evolution of hemispheric asymmetry. PMID:26511047

  10. Effect of vesicle traps on traffic jam formation in fast axonal transport.

    Science.gov (United States)

    Kuznetsov, A V

    2010-08-01

    The purpose of this paper is to develop a model for simulation of the formation of organelle traps in fast axonal transport. Such traps may form in the regions of microtubule polar mismatching. Depending on the orientation of microtubules pointing toward the trap region, these traps can accumulate either plus-end or minus-end oriented vesicles. The model predicts that the maximum concentrations of organelles occur at the boundaries of the trap regions; the overall concentration of organelles in the axon with traps is greatly increased compared to that in a healthy axon, which is expected to contribute to mechanical damages of the axon. The organelle traps induce hindrance to organelle transport down the axon; the total organelle flux down the axon with traps is found to be significantly reduced compared to that in a healthy axon.

  11. Regulation of neuronal axon specification by glia-neuron gap junctions in C. elegans

    Science.gov (United States)

    Meng, Lingfeng; Zhang, Albert; Jin, Yishi; Yan, Dong

    2016-01-01

    Axon specification is a critical step in neuronal development, and the function of glial cells in this process is not fully understood. Here, we show that C. elegans GLR glial cells regulate axon specification of their nearby GABAergic RME neurons through GLR-RME gap junctions. Disruption of GLR-RME gap junctions causes misaccumulation of axonal markers in non-axonal neurites of RME neurons and converts microtubules in those neurites to form an axon-like assembly. We further uncover that GLR-RME gap junctions regulate RME axon specification through activation of the CDK-5 pathway in a calcium-dependent manner, involving a calpain clp-4. Therefore, our study reveals the function of glia-neuron gap junctions in neuronal axon specification and shows that calcium originated from glial cells can regulate neuronal intracellular pathways through gap junctions. DOI: http://dx.doi.org/10.7554/eLife.19510.001 PMID:27767956

  12. Interplay between kinesin-1 and cortical dynein during axonal outgrowth and microtubule organization in Drosophila neurons.

    Science.gov (United States)

    del Castillo, Urko; Winding, Michael; Lu, Wen; Gelfand, Vladimir I

    2015-12-28

    In this study, we investigated how microtubule motors organize microtubules in Drosophila neurons. We showed that, during the initial stages of axon outgrowth, microtubules display mixed polarity and minus-end-out microtubules push the tip of the axon, consistent with kinesin-1 driving outgrowth by sliding antiparallel microtubules. At later stages, the microtubule orientation in the axon switches from mixed to uniform polarity with plus-end-out. Dynein knockdown prevents this rearrangement and results in microtubules of mixed orientation in axons and accumulation of microtubule minus-ends at axon tips. Microtubule reorganization requires recruitment of dynein to the actin cortex, as actin depolymerization phenocopies dynein depletion, and direct recruitment of dynein to the membrane bypasses the actin requirement. Our results show that cortical dynein slides 'minus-end-out' microtubules from the axon, generating uniform microtubule arrays. We speculate that differences in microtubule orientation between axons and dendrites could be dictated by differential activity of cortical dynein.

  13. Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins.

    Science.gov (United States)

    Gainer, Harold; House, Shirley; Kim, Dong Sun; Chin, Hemin; Pant, Harish C

    2017-04-01

    When isolated squid giant axons are incubated in radioactive amino acids, abundant newly synthesized proteins are found in the axoplasm. These proteins are translated in the adaxonal Schwann cells and subsequently transferred into the giant axon. The question as to whether any de novo protein synthesis occurs in the giant axon itself is difficult to resolve because the small contribution of the proteins possibly synthesized intra-axonally is not easily distinguished from the large amounts of the proteins being supplied from the Schwann cells. In this paper, we reexamine this issue by studying the synthesis of endogenous neurofilament (NF) proteins in the axon. Our laboratory previously showed that NF mRNA and protein are present in the squid giant axon, but not in the surrounding adaxonal glia. Therefore, if the isolated squid axon could be shown to contain newly synthesized NF protein de novo, it could not arise from the adaxonal glia. The results of experiments in this paper show that abundant 3H-labeled NF protein is synthesized in the squid giant fiber lobe containing the giant axon's neuronal cell bodies, but despite the presence of NF mRNA in the giant axon no labeled NF protein is detected in the giant axon. This lends support to the glia-axon protein transfer hypothesis which posits that the squid giant axon obtains newly synthesized protein by Schwann cell transfer and not through intra-axonal protein synthesis, and further suggests that the NF mRNA in the axon is in a translationally repressed state.

  14. ¿Hay un mal en morir? Consideraciones éticas y jurídicas sobre la muerte inducida

    Directory of Open Access Journals (Sweden)

    ALEJANDRA ZÚÑIGA F.

    2011-01-01

    Full Text Available Se analizan los dilemas morales asociados a la muerte, para reflexionar sobre los interrogantes que surgen al calificarla como un hecho banal desde la perspectiva de quien muere. Se estudian, además, las consecuencias éticas y jurídicas de reconocer autonomía moral a quienes deciden, en circunstancias extremas, tomar por sí mismos la decisión de cuándo y cómo morir.

  15. Axon and muscle spindle hyperplasia in the myostatin null mouse.

    Science.gov (United States)

    Elashry, Mohamed I; Otto, Anthony; Matsakas, Antonios; El-Morsy, Salah E; Jones, Lisa; Anderson, Bethan; Patel, Ketan

    2011-02-01

    Germline deletion of the myostatin gene results in hyperplasia and hypertrophy of the tension-generating (extrafusal) fibres in skeletal muscle. As this gene is expressed predominantly in myogenic tissues it offers an excellent model with which to investigate the quantitative relationship between muscle and axonal development. Here we show that skeletal muscle hyperplasia in myostatin null mouse is accompanied by an increase in nerve fibres in major nerves of both the fore- and hindlimbs. We show that axons within these nerves undergo hypertrophy. Furthermore, we provide evidence that the age-related neural atrophic process is delayed in the absence of myostatin. Finally, we show that skeletal muscle hyperplasia in the myostatin null mouse is accompanied by an increase in the number of muscle spindles (also called stretch receptors or proprioceptors). However, our work demonstrates that the mechanisms regulating intrafusal fibre hyperplasia and hypertrophy differ from those that control the aetiology of extrafusal fibres.

  16. Coevolution of axon guidance molecule Slit and its receptor Robo.

    Science.gov (United States)

    Yu, Qi; Li, Xiao-Tong; Zhao, Xiao; Liu, Xun-Li; Ikeo, Kazuho; Gojobori, Takashi; Liu, Qing-Xin

    2014-01-01

    Coevolution is important for the maintenance of the interaction between a ligand and its receptor during evolution. The interaction between axon guidance molecule Slit and its receptor Robo is critical for the axon repulsion in neural tissues, which is evolutionarily conserved from planarians to humans. However, the mechanism of coevolution between Slit and Robo remains unclear. In this study, we found that coordinated amino acid changes took place at interacting sites of Slit and Robo by comparing the amino acids at these sites among different organisms. In addition, the high level correlation between evolutionary rate of Slit and Robo was identified in vertebrates. Furthermore, the sites under positive selection of slit and robo were detected in the same lineage such as mosquito and teleost. Overall, our results provide evidence for the coevolution between Slit and Robo.

  17. Antiretroviral Therapy-Associated Acute Motor and Sensory Axonal Neuropathy

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    Kimberly N. Capers

    2011-01-01

    Full Text Available Guillain-Barré syndrome (GBS has been reported in HIV-infected patients in association with the immune reconstitution syndrome whose symptoms can be mimicked by highly active antiretroviral therapy (HAART-mediated mitochondrial toxicity. We report a case of a 17-year-old, HIV-infected patient on HAART with a normal CD4 count and undetectable viral load, presenting with acute lower extremity weakness associated with lactatemia. Electromyography/nerve conduction studies revealed absent sensory potentials and decreased compound muscle action potentials, consistent with a diagnosis of acute motor and sensory axonal neuropathy. Lactatemia resolved following cessation of HAART; however, neurological deficits minimally improved over several months in spite of immune modulatory therapy. This case highlights the potential association between HAART, mitochondrial toxicity and acute axonal neuropathies in HIV-infected patients, distinct from the immune reconstitution syndrome.

  18. Coevolution of axon guidance molecule Slit and its receptor Robo.

    Directory of Open Access Journals (Sweden)

    Qi Yu

    Full Text Available Coevolution is important for the maintenance of the interaction between a ligand and its receptor during evolution. The interaction between axon guidance molecule Slit and its receptor Robo is critical for the axon repulsion in neural tissues, which is evolutionarily conserved from planarians to humans. However, the mechanism of coevolution between Slit and Robo remains unclear. In this study, we found that coordinated amino acid changes took place at interacting sites of Slit and Robo by comparing the amino acids at these sites among different organisms. In addition, the high level correlation between evolutionary rate of Slit and Robo was identified in vertebrates. Furthermore, the sites under positive selection of slit and robo were detected in the same lineage such as mosquito and teleost. Overall, our results provide evidence for the coevolution between Slit and Robo.

  19. Morphology of axonal transport abnormalities in primate eyes.

    OpenAIRE

    Radius, R L; Anderson, D. R.

    1981-01-01

    The ultrastructure of the retina and optic nerve head was studied in primate eyes after central retinal artery occlusion. Within 2 hours of the vascular occlusion the inner retinal layers undergo watery (isosmotic) swelling. This watery swelling of axons and astroglia extends into the nerve head as far back as the anterior boundary of the scleral lamina cribrosa. The swelling is increased 4 hours after the occlusion, and by 24 hours disintegration has occurred. At the optic nerve head mitocho...

  20. Cortical Interneuron Subtypes Vary in Their Axonal Action Potential Properties

    OpenAIRE

    Casale, Amanda E.; Foust, Amanda J.; Bal, Thierry; McCormick, David A.

    2015-01-01

    The role of interneurons in cortical microcircuits is strongly influenced by their passive and active electrical properties. Although different types of interneurons exhibit unique electrophysiological properties recorded at the soma, it is not yet clear whether these differences are also manifested in other neuronal compartments. To address this question, we have used voltage-sensitive dye to image the propagation of action potentials into the fine collaterals of axons and dendrites in two o...

  1. Axonal Dysfunction Precedes Motor Neuronal Death in Amyotrophic Lateral Sclerosis.

    Directory of Open Access Journals (Sweden)

    Yuta Iwai

    Full Text Available Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS, suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP amplitude (index of motor neuronal loss and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44, ALS patients (n = 140 had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p 5mV. Regression analyses showed that SDTC (R = -0.22 and depolarizing threshold electrotonus (R = -0.22 increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS.

  2. Efficient simulations of tubulin-driven axonal growth.

    Science.gov (United States)

    Diehl, Stefan; Henningsson, Erik; Heyden, Anders

    2016-08-01

    This work concerns efficient and reliable numerical simulations of the dynamic behaviour of a moving-boundary model for tubulin-driven axonal growth. The model is nonlinear and consists of a coupled set of a partial differential equation (PDE) and two ordinary differential equations. The PDE is defined on a computational domain with a moving boundary, which is part of the solution. Numerical simulations based on standard explicit time-stepping methods are too time consuming due to the small time steps required for numerical stability. On the other hand standard implicit schemes are too complex due to the nonlinear equations that needs to be solved in each step. Instead, we propose to use the Peaceman-Rachford splitting scheme combined with temporal and spatial scalings of the model. Simulations based on this scheme have shown to be efficient, accurate, and reliable which makes it possible to evaluate the model, e.g. its dependency on biological and physical model parameters. These evaluations show among other things that the initial axon growth is very fast, that the active transport is the dominant reason over diffusion for the growth velocity, and that the polymerization rate in the growth cone does not affect the final axon length.

  3. Axon clinical chemistry analyzer evaluated according to ECCLS protocol.

    Science.gov (United States)

    Brenna, S; Prencipe, L

    1992-10-01

    We assessed the analytical performance of the Axon system (Bayer Diagnostici), according to the European Committee for Clinical Laboratory Standards guidelines, for assay of 12 analytes: cholesterol, creatinine, glucose, total protein, urea, uric acid, alkaline phosphatase, alpha-amylase, aspartate aminotransferase, creatine kinase, sodium, and potassium. The field evaluation lasted approximately 5 months and involved the collection of approximately 10,000 data points with the Axon. The following results were obtained: The highest CVs for controls and human sera at different concentration/activity values were 2.2% for within-run imprecision (n = 60; 3 days, pooled estimate) and 3.5% for the between-day imprecision (n = 20 days). Close correlation was found with results for patients' specimens assayed with comparative instruments (Hitachi 717 for substrates and enzymes, Beckman Synchron EL/E4A for electrolytes). No drift was observed during 8 h of operation. The linearity range was broad, sometimes exceeding the manufacturer's claims. No sample-, reagent-, or cuvette-related carryover was found. Measurement of control sera gave results within +/- 5% of the assigned values. We conclude that good reliability and practicability make the Axon system suitable for laboratories with various needs.

  4. Loss of Saltation and Presynaptic Action Potential Failure in Demyelinated Axons

    Science.gov (United States)

    Hamada, Mustafa S.; Popovic, Marko A.; Kole, Maarten H. P.

    2017-01-01

    In cortical pyramidal neurons the presynaptic terminals controlling transmitter release are located along unmyelinated axon collaterals, far from the original action potential (AP) initiation site, the axon initial segment (AIS). Once initiated, APs will need to reliably propagate over long distances and regions of geometrical inhomogeneity like branch points (BPs) to rapidly depolarize the presynaptic terminals and confer temporally precise synaptic transmission. While axon pathologies such as demyelinating diseases are well established to impede the fidelity of AP propagation along internodes, to which extent myelin loss affects propagation along BPs and axon collaterals is not well understood. Here, using the cuprizone demyelination model, we performed optical voltage-sensitive dye (VSD) imaging from control and demyelinated layer 5 pyramidal neuron axons. In the main axon, we find that myelin loss switches the modality of AP propagation from rapid saltation towards a slow continuous wave. The duration of single AP waveforms at BPs or nodes was, however, only slightly briefer. In contrast, by using two-photon microscopy-guided loose-seal patch recordings from axon collaterals we revealed a presynaptic AP broadening in combination with a reduced velocity and frequency-dependent failure. Finally, internodal myelin loss was also associated with de novo sprouting of axon collaterals starting from the primary (demyelinated) axon. Thus, the loss of oligodendrocytes and myelin sheaths bears functional consequences beyond the main axon, impeding the temporal fidelity of presynaptic APs and affecting the functional and structural organization of synaptic connectivity within the neocortex.

  5. Regulation of action potential waveforms by axonal GABAA receptors in cortical pyramidal neurons.

    Directory of Open Access Journals (Sweden)

    Yang Xia

    Full Text Available GABAA receptors distributed in somatodendritic compartments play critical roles in regulating neuronal activities, including spike timing and firing pattern; however, the properties and functions of GABAA receptors at the axon are still poorly understood. By recording from the cut end (bleb of the main axon trunk of layer -5 pyramidal neurons in prefrontal cortical slices, we found that currents evoked by GABA iontophoresis could be blocked by picrotoxin, indicating the expression of GABAA receptors in axons. Stationary noise analysis revealed that single-channel properties of axonal GABAA receptors were similar to those of somatic receptors. Perforated patch recording with gramicidin revealed that the reversal potential of the GABA response was more negative than the resting membrane potential at the axon trunk, suggesting that GABA may hyperpolarize the axonal membrane potential. Further experiments demonstrated that the activation of axonal GABAA receptors regulated the amplitude and duration of action potentials (APs and decreased the AP-induced Ca2+ transients at the axon. Together, our results indicate that the waveform of axonal APs and the downstream Ca2+ signals are modulated by axonal GABAA receptors.

  6. Intra-axonal protein synthesis - a new target for neural repair?

    Directory of Open Access Journals (Sweden)

    Jeffery L Twiss

    2016-01-01

    Full Text Available Although initially argued to be a feature of immature neurons with incomplete polarization, there is clear evidence that neurons in the peripheral nervous system retain the capacity for intra-axonal protein synthesis well into adulthood. This localized protein synthesis has been shown to contribute to injury signaling and axon regeneration in peripheral nerves. Recent works point to potential for protein synthesis in axons of the vertebrate central nervous system. mRNAs and protein synthesis machinery have now been documented in lamprey, mouse, and rat spinal cord axons. Intra-axonal protein synthesis appears to be activated in adult vertebrate spinal cord axons when they are regeneration-competent. Rat spinal cord axons regenerating into a peripheral nerve graft contain mRNAs and markers of activated translational machinery. Indeed, levels of some growth-associated mRNAs in these spinal cord axons are comparable to the regenerating sciatic nerve. Markers of active translation tend to decrease when these axons stop growing, but can be reactivated by a second axotomy. These emerging observations raise the possibility that mRNA transport into and translation within axons could be targeted to facilitate regeneration in both the peripheral and central nervous systems.

  7. Intra-axonal protein synthesis - a new target for neural repair?

    Science.gov (United States)

    Twiss, Jeffery L; Kalinski, Ashley L; Sachdeva, Rahul; Houle, John D

    2016-09-01

    Although initially argued to be a feature of immature neurons with incomplete polarization, there is clear evidence that neurons in the peripheral nervous system retain the capacity for intra-axonal protein synthesis well into adulthood. This localized protein synthesis has been shown to contribute to injury signaling and axon regeneration in peripheral nerves. Recent works point to potential for protein synthesis in axons of the vertebrate central nervous system. mRNAs and protein synthesis machinery have now been documented in lamprey, mouse, and rat spinal cord axons. Intra-axonal protein synthesis appears to be activated in adult vertebrate spinal cord axons when they are regeneration-competent. Rat spinal cord axons regenerating into a peripheral nerve graft contain mRNAs and markers of activated translational machinery. Indeed, levels of some growth-associated mRNAs in these spinal cord axons are comparable to the regenerating sciatic nerve. Markers of active translation tend to decrease when these axons stop growing, but can be reactivated by a second axotomy. These emerging observations raise the possibility that mRNA transport into and translation within axons could be targeted to facilitate regeneration in both the peripheral and central nervous systems.

  8. Intra-axonal protein synthesis - a new target for neural repair?

    Institute of Scientific and Technical Information of China (English)

    Jeffery L Twiss; Ashley L Kalinski; Rahul Sachdeva; John D Houle

    2016-01-01

    Although initially argued to be a feature of immature neurons with incomplete polarization, there is clear evidence that neurons in the peripheral nervous system retain the capacity for intra-axonal protein synthe-sis well into adulthood. This localized protein synthesis has been shown to contribute to injury signaling and axon regeneration in peripheral nerves. Recent works point to potential for protein synthesis in axons of the vertebrate central nervous system. mRNAs and protein synthesis machinery have now been docu-mented in lamprey, mouse, and rat spinal cord axons. Intra-axonal protein synthesis appears to be activated in adult vertebrate spinal cord axons when they are regeneration-competent. Rat spinal cord axons regen-erating into a peripheral nerve graft contain mRNAs and markers of activated translational machinery. Indeed, levels of some growth-associated mRNAs in these spinal cord axons are comparable to the regen-erating sciatic nerve. Markers of active translation tend to decrease when these axons stop growing, but can be reactivated by a second axotomy. These emerging observations raise the possibility that mRNA transport into and translation within axons could be targeted to facilitate regeneration in both the peripheral and central nervous systems.

  9. Organophosphate-induced delayed neuropathy: case report Neuropatia tardia por organofosforado: relato de caso

    Directory of Open Access Journals (Sweden)

    Luiz Felipe R Vasconcellos

    2002-12-01

    Full Text Available Organophosphate induced delayed neuropathy (OPIDN is an uncommon clinical condition. It occurs in association with the ingestion of great amounts of organophosphate after the stimulation of cholinergic receptor. The clinical picture is characterized by a distal paresis in lower limbs associated with sensitive symptoms. Electrodiagnostic studies show a motor axonal neuropathy. Involvement of the central nervous system may occur. We describe a 39 years-old female patient who developed hyperesthesia associated with lower limbs paresis, fourteen days after she had ingested a Dichlorvos-based insecticide. Electrophysiological study was characterized by an axonal polyneuropathy pattern. Pyramidal tract dysfunction was observed later in upper limbs. Considering that both peripheral and central nervous systems are involved we believe that the more appropriated term would be organophosphate induced delayed neuropathy (OPIDN instead of organophosphate induced delayed polyneuropathy (OPIDP.A neuropatia tardia dos organofosforados (NTOF é condição clinica incomum. Geralmente ocorre após a intoxicação aguda por organofosforados, seguindo-se a fase de hiperestimulação colinérgica. O quadro clínico é caracterizado por déficit motor distal nos membros inferiores associado a sintomas sensitivos. O estudo eletroneuromiográfico tem demonstrado padrão axonal motor na maioria dos casos. Podem ocorrer sinais de comprometimento do sistema nervoso central. Descrevemos o caso de uma paciente de 39 anos que ingeriu inseticida a base de Dichlorvos e quatorze dias após apresentou quadro de hiperestesia associado a paresia distal nos membros inferiores. Realizou eletroneuromiografia que se caracterizou por padrão compatível com polineuropatia axonal. Sinais piramidais, de aparecimento mais tardio, foram observados nos membros superiores. Diante do comprometimento do sistema nervoso periférico e central, também consideramos o termo neuropatia tardia por

  10. ROCK2 is a major regulator of axonal degeneration, neuronal death and axonal regeneration in the CNS.

    Science.gov (United States)

    Koch, J C; Tönges, L; Barski, E; Michel, U; Bähr, M; Lingor, P

    2014-05-15

    The Rho/ROCK/LIMK pathway is central for the mediation of repulsive environmental signals in the central nervous system. Several studies using pharmacological Rho-associated protein kinase (ROCK) inhibitors have shown positive effects on neurite regeneration and suggest additional pro-survival effects in neurons. However, as none of these drugs is completely target specific, it remains unclear how these effects are mediated and whether ROCK is really the most relevant target of the pathway. To answer these questions, we generated adeno-associated viral vectors to specifically downregulate ROCK2 and LIM domain kinase (LIMK)-1 in rat retinal ganglion cells (RGCs) in vitro and in vivo. We show here that specific knockdown of ROCK2 and LIMK1 equally enhanced neurite outgrowth of RGCs on inhibitory substrates and both induced substantial neuronal regeneration over distances of more than 5 mm after rat optic nerve crush (ONC) in vivo. However, only knockdown of ROCK2 but not LIMK1 increased survival of RGCs after optic nerve axotomy. Moreover, knockdown of ROCK2 attenuated axonal degeneration of the proximal axon after ONC assessed by in vivo live imaging. Mechanistically, we demonstrate here that knockdown of ROCK2 resulted in decreased intraneuronal activity of calpain and caspase 3, whereas levels of pAkt and collapsin response mediator protein 2 and autophagic flux were increased. Taken together, our data characterize ROCK2 as a specific therapeutic target in neurodegenerative diseases and demonstrate new downstream effects of ROCK2 including axonal degeneration, apoptosis and autophagy.

  11. Luxación témporo-mandibular recurrente y secundaria a distonía por antipsicóticos.

    OpenAIRE

    2016-01-01

    La distonía aguda inducida por antipsicóticos sigue siendo una patología frecuente en los servicios de emergencia psiquiátrica. Sin embargo, la luxación de la articulación témporo-mandibular, como secuela de distonía oromandibular, es una presentación inusual dentro de esta casuística. Presentamos el caso de una paciente mujer de 20 años de edad, quien recibió haloperidol intramuscular tras sendas crisis de agitación psicomotriz y persistencia de riesgo suicida, y que luego desarrolló distoní...

  12. Tasa de infección de la pudrición del tallo en maíz causada por Fusarium moniliforme

    OpenAIRE

    Mariano Mendoza Elos; Enrique Andrio Enr\\u00EDquez; Alfonso L\\u00F3pez Ben\\u00EDtez; Ra\\u00FAl Rodr\\u00EDguez Guerra; Luis Latournerie Moreno; Sergio A. Rodr\\u00EDguez Herrera

    2006-01-01

    Tasa de infección de la pudrición del tallo en maíz causada por Fusarium moniliforme. El objetivo de éste trabajo fue determinar la resistencia horizontal de 134 líneas S1 de maíz al hongo Fusarium moniliforme. La enfermedad fue inducida mediante inoculación en la etapa de floración masculina bajo condiciones de campo utilizando la técnica del palillo. Las líneas se evaluaron en México en 2002. La estimación de la enfermedad se hizo en dos ocasiones con una separación de 20 días. Las evaluaci...

  13. PRODUCCIÓN DE NANOPARTÍCULAS DEL SISTEMA Al‐Cu‐Fe POR MOLIENDA MECÁNICA PARA SINTETIZAR NANOESTRUCTURAS DE CARBONO Y PRODUCCIÓN DE HIDRÓGENO

    OpenAIRE

    Patiño Carachure, Cristobal

    2012-01-01

    En este trabajo, se estudia la síntesis de nanoestructuras de carbono empleando como un nuevo método, la molienda mecánica de nanopartículas del sistema Al-Cu-Fe en un medio de etanol. Siendo éste una fuente de carbono. Por otro lado, también es evaluada la producción de hidrógeno como subproducto de la reacción de fragilización inducida por la molienda mecánica de bolas en un medio húmedo de las aleaciones, cuya composición poseen una cantidad de aluminio en mayor proporción. ...

  14. Estudios preliminares sobre la actividad hipoglicémica y antihiperlipidemica de nanomatrices de TiO2 con extracto de Stevia rebaudiana bertoni en ratas diabéticas inducidas con aloxano

    OpenAIRE

    Alfonso Díaz; Oscar Villegas; Alejandra Castro Lino; Samuel Treviño; Genaro Carmona-Gutiérrez; Marco Antonio González-Coronel; José Albino Moreno-Rodríguez

    2013-01-01

    Actualmente, la nanotecnología farmacéutica se enfoca al desarrollo de formulaciones de agentes terapéuticos en nanocomplejos biocompatibles como las nanomatrices. En este proyecto se evaluó el efecto antidiabético de las nanomatrices de óxido de titanio (TiO2) con extracto de Stevia rebaudiana bertoni (TiO2-SrB), una planta con propiedades hipoglucemiantes y antihiperlipidemicas en ratas diabéticas inducidas con aloxano (200 mg/kg, ip). Los resultados muestran la disminución significativa en...

  15. Role of calpains in the injury-induced dysfunction and degeneration of the mammalian axon.

    Science.gov (United States)

    Ma, Marek

    2013-12-01

    Axonal injury and degeneration, whether primary or secondary, contribute to the morbidity and mortality seen in many acquired and inherited central nervous system (CNS) and peripheral nervous system (PNS) disorders, such as traumatic brain injury, spinal cord injury, cerebral ischemia, neurodegenerative diseases, and peripheral neuropathies. The calpain family of proteases has been mechanistically linked to the dysfunction and degeneration of axons. While the direct mechanisms by which transection, mechanical strain, ischemia, or complement activation trigger intra-axonal calpain activity are likely different, the downstream effects of unregulated calpain activity may be similar in seemingly disparate diseases. In this review, a brief examination of axonal structure is followed by a focused overview of the calpain family. Finally, the mechanisms by which calpains may disrupt the axonal cytoskeleton, transport, and specialized domains (axon initial segment, nodes, and terminals) are discussed.

  16. Coculture of elongated neuron axon with poly (D, L-lactide-co-glycolide) biomembrane in vitro

    Institute of Scientific and Technical Information of China (English)

    程飚; 陈峥嵘

    2004-01-01

    Objective: To elongate human nerve axon in culture and search for suitable support matrices for peripheral nervous system transplantation.Methods: Human embryo cortical neuronal cells,seeded on poly ( D, L-lactide-co-glycolide ) ( PLGA )membrane scaffolds, were elongated with a self-made neuro-axon extending device. The growth and morphological changes of neuron axons were observed to measure axolemmal permeability after elongation.Neurofilament protein was stained by immunohistochemical technique.Results: Human embryo neuron axon could be elongated and cultured on the PLGA membrane and retain their normal form and function.Conclusions: Three dimensional scaffolds with elongated neuron axon have the basic characteristics of artificial nerves, indicating a fundemental theory of nerve repair with elongated neuron axon.

  17. JMJD-1.2/PHF8 controls axon guidance by regulating Hedgehog-like signaling

    DEFF Research Database (Denmark)

    Riveiro, Alba; Mariani, Luca; Malmberg, Kim Emily

    2017-01-01

    . Here, we show that the catalytic activity of a PHF8 homolog in Caenorhabditis elegans, JMJD-1.2, is required non-cell-autonomously for proper axon guidance. Loss of JMJD-1.2 dysregulates transcription of the Hedgehog-related genes wrt-8 and grl-16, the overexpression of which is sufficient to induce...... the axonal defects. Deficiency of either wrt-8 or grl-16, or reduced expression of homologs of genes promoting Hedgehog signaling, restores correct axon guidance in jmjd-1.2 mutants. Genetic and overexpression data indicate that Hedgehog-related genes act on axon guidance through actin remodelers. Thus, our...... study highlights a novel function of jmjd-1.2 in axon guidance that might be relevant for the onset of X-linked mental retardation and provides compelling evidence of a conserved function of the Hedgehog pathway in C. elegans axon migration....

  18. Sonic hedgehog regulates its own receptor on postcrossing commissural axons in a glypican1-dependent manner.

    Science.gov (United States)

    Wilson, Nicole H; Stoeckli, Esther T

    2013-08-07

    Upon reaching their intermediate target, the floorplate, commissural axons acquire responsiveness to repulsive guidance cues, allowing the axons to exit the midline and adopt a contralateral, longitudinal trajectory. The molecular mechanisms that regulate this switch from attraction to repulsion remain poorly defined. Here, we show that the heparan sulfate proteoglycan Glypican1 (GPC1) is required as a coreceptor for the Shh-dependent induction of Hedgehog-interacting protein (Hhip) in commissural neurons. In turn, Hhip is required for postcrossing axons to respond to a repulsive anteroposterior Shh gradient. Thus, Shh is a cue with dual function. In precrossing axons it acts as an attractive guidance molecule in a transcription-independent manner. At the same time, Shh binds to GPC1 to induce the expression of its own receptor, Hhip, which mediates the repulsive response of postcrossing axons to Shh. Our study characterizes a molecular mechanism by which navigating axons switch their responsiveness at intermediate targets.

  19. Trafifc lights for axon growth:proteoglycans and their neuronal receptors

    Institute of Scientific and Technical Information of China (English)

    Yingjie Shen

    2014-01-01

    Axon growth is a central event in the development and post-injury plasticity of the nervous system. Growing axons encounter a wide variety of environmental instructions. Much like trafifc lights in controlling the migrating axons, chondroitin sulfate proteoglycans (CSPGs) and hepa-ran sulfate proteoglycans (HSPGs) often lead to“stop”and“go”growth responses in the axons, respectively. Recently, the LAR family and NgR family molecules were identified as neuronal receptors for CSPGs and HSPGs. These discoveries provided molecular tools for further study of mechanisms underlying axon growth regulation. More importantly, the identiifcation of these proteoglycan receptors offered potential therapeutic targets for promoting post-injury axon re-generation.

  20. Regeneración axonal posterior a lesiones traumáticas de médula espinal: Papel crítico de galectina-1

    Directory of Open Access Journals (Sweden)

    Héctor R Quintá

    2014-08-01

    Full Text Available Al producirse una lesión de médula espinal (LME, un sinnúmero de proteínas inhibidoras de la regeneración axonal ocupan el sitio de lesión en forma secuencial. La primer proteína en llegar al mismo se conoce como semaforina 3A (Sema3A, siendo además una de las más potentes por su acción de inhibir la regeneración axonal. A nivel mecanístico la unión de esta proteína al complejo-receptor neuronal neuropilin-1 (NRP-1/PlexinA4 evita que se produzca regeneración axonal. En este trabajo de revisión se discutirá la acción de galectin-1 (Gal-1, una proteína endógena de unión a glicanos, que selectivamente se une al complejo-receptor NRP-1/PlexinA4 de las neuronas lesionadas a través de un mecanismo dependiente de interacciones lectina-glicano, interrumpiendo la señalización generada por Sema3A y permitiendo de esta manera la regeneración axonal y recuperación locomotora luego de producirse la LME. Mientras ambas formas de Gal-1 (monomérica y dimérica contribuyen a la inactivación de la microglia, solo la forma dimérica de Gal-1 es capaz de unirse al complejo-receptor NRP-1/PlexinA4 y promover regeneración axonal. Por lo tanto, Gal-1 dimérica produce recuperación de las lesiones espinales interfiriendo en la señalización de Sema3A a través de la unión al complejo-receptor NRP-1/PlexinA4, sugiriendo el uso de esta lectina en su forma dimérica para el tratamiento de pacientes con LME.

  1. Empiema por Fusobacterium necrophorum

    OpenAIRE

    ML. Valle Feijoo; M. Rodriguez Arias; A. Cobas Paz; J. De la Fuente Aguado

    2014-01-01

    Resumen La infección sistémica por Fusobacterium necrophorum se caracteriza por la tríada clásica de trombosis de la vena yugular interna, bacteriemia y focos metastásicos y se conoce como Síndrome de Lemierre (SL), sepsis post-angina o necrobacilosis. El compromiso pulmonar precipitado por la embolización séptica es extremadamente común en el SL, sin embargo el F. necrohorum raramente se asila en empiemas sin SL concurrente, por lo que hemos estimado oportuno comunicar un nuevo caso clíni...

  2. Celulitis por citomegalovirus

    OpenAIRE

    2002-01-01

    Las lesiones cutáneas por citomegalovirus (CMV) son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritemato...

  3. Promoting Axon Regeneration in the Adult CNS by Modulation of the PTEN/mTOR Pathway

    OpenAIRE

    2008-01-01

    The failure of axons to regenerate is a major obstacle for functional recovery after central nervous system (CNS) injury. Removing extracellular inhibitory molecules results in limited axon regeneration in vivo. To test for the role of intrinsic impediments to axon regrowth, we analyzed cell growth control genes using a virus-assisted in vivo conditional knockout approach. Deletion of PTEN (phosphatase and tensin homolog), a negative regulator of the mammalian target of rapamycin (mTOR) pathw...

  4. ATP7A (Menkes Protein) functions in Axonal Targeting and Synaptogenesis

    OpenAIRE

    Meskini, Rajaâ El; Crabtree, Kelli L.; Cline, Laura B.; Mains, Richard E.; Eipper, Betty A.; Ronnett, Gabriele V.

    2007-01-01

    Menkes Disease (MD) is a neurodegenerative disorder caused by mutations in the copper transporter, ATP7A, a P-type ATPase. We previously used the olfactory system to demonstrate that ATP7A expression is developmentally, not constitutive, regulated, peaking during synaptogenesis when it is highly expressed in extending axons in a copper-independent manner. Although not known to be associated with axonal functions, we explored the possibility that the inability of mutant ATP7A to support axon o...

  5. Cyclophilin D Deficiency Rescues Axonal Mitochondrial Transport in Alzheimer’s Neurons

    OpenAIRE

    Lan Guo; Heng Du; Shiqiang Yan; Xiaoping Wu; Guy M. McKhann; John Xi Chen; Shirley ShiDu Yan

    2013-01-01

    Normal axonal mitochondrial transport and function is essential for the maintenance of synaptic function. Abnormal mitochondrial motility and mitochondrial dysfunction within axons are critical for amyloid β (Aβ)-induced synaptic stress and the loss of synapses relevant to the pathogenesis of Alzheimer's disease (AD). However, the mechanisms controlling axonal mitochondrial function and transport alterations in AD remain elusive. Here, we report an unexplored role of cyclophilin D (CypD)-depe...

  6. Influencia mutua de la deformación y composición química sobre la precipitación inducida en aceros microaleados

    Directory of Open Access Journals (Sweden)

    Quispe, A.

    2005-12-01

    Full Text Available By means of torsion tests and applying the "back extrapolation" method, the static recrystallization kinetics in microalloyed steels with vanadium (V, niobium (Nb and titanium (Ti has been determined and, recrystallization-precipitation-time-temperature (RPTT diagrams have been plotted also graphically, which show the Recrystallization- Precipitation interaction. These diagrams show that the effect of the deformation on the precipitation kinetics depends of the microalloy content. In this sense, a new expression is proposed to relate the influence of the deformation and the chemical composition on the minimum incubation of the precipitation kinetics.

    Mediante ensayos de torsión y usando el método back extrapolation se ha determinado la cinética de recristalización estática de aceros microaleados con vanadio (V, niobio (Nb y titanio (Ti y, a partir de las mismas, ha sido posible dibujar los diagramas recristalizaciónprecipitación- tiempo-temperatura (RPTT, que muestran gráficamente la interacción recristalización-precipitación. Estos diagramas muestran que el efecto de la deformación en la cinética de precipitación depende del contenido de microaleante. En este sentido, se propone una nueva expresión para relacionar la influencia de la deformación y del contenido de microaleante sobre el periodo mínimo de incubación de la precipitación inducida.

  7. TOLERANCIA A ESTRÉS POR DÉFICIT HÍDRICO EN TOMATE (Solanum lycopersicum L.

    Directory of Open Access Journals (Sweden)

    Marilyn Florido Bacallao

    2014-01-01

    Full Text Available El agua es uno de los factores más importantes para el desarrollo de las plantas, por lo tanto, su carencia constituye una de las principales fuentes de estrés. En este artículo se recogen algunos aspectos sobre las diferentes respuestas a nivel morfológico, fisiológico y bioquímico en tomate que le permite adaptarse o tolerar el estrés por déficit hídrico. Estas respuestas incluyen modificaciones en el crecimiento, el desarrollo, cierre de estomas y cambios en la expresión de genes, incluyendo los que codifican proteínas protectoras, enzimas clave en la vía de síntesis de osmolitos, enzimas antioxidantes y factores de transcripción que regulan la expresión de genes inducida por el estrés, así como las nuevas herramientas de genómica funcional. También se incluyen aspectos relacionados con la mejora para tolerancia a la sequía en el cultivo.

  8. Thiazolidinediones Promote Axonal Growth through the Activation of the JNK Pathway

    Science.gov (United States)

    Quintanilla, Rodrigo A.; Godoy, Juan A.; Alfaro, Ivan; Cabezas, Deny; von Bernhardi, Rommy; Bronfman, Miguel; Inestrosa, Nibaldo C.

    2013-01-01

    The axon is a neuronal process involved in protein transport, synaptic plasticity, and neural regeneration. It has been suggested that their structure and function are profoundly impaired in neurodegenerative diseases. Previous evidence suggest that Peroxisome Proliferator-Activated Receptors-γ (PPARγ promote neuronal differentiation on various neuronal cell types. In addition, we demonstrated that activation of PPARγby thiazolidinediones (TZDs) drugs that selectively activate PPARγ prevent neurite loss and axonal damage induced by amyloid-β (Aβ). However, the potential role of TZDs in axonal elongation and neuronal polarity has not been explored. We report here that the activation of PPARγ by TZDs promoted axon elongation in primary hippocampal neurons. Treatments with different TZDs significantly increased axonal growth and branching area, but no significant effects were observed in neurite elongation compared to untreated neurons. Treatment with PPARγ antagonist (GW 9662) prevented TZDs-induced axonal growth. Recently, it has been suggested that the c-Jun N-terminal kinase (JNK) plays an important role regulating axonal growth and neuronal polarity. Interestingly, in our studies, treatment with TZDs induced activation of the JNK pathway, and the pharmacological blockage of this pathway prevented axon elongation induced by TZDs. Altogether, these results indicate that activation of JNK induced by PPARγactivators stimulates axonal growth and accelerates neuronal polarity. These novel findings may contribute to the understanding of the effects of PPARγ on neuronal differentiation and validate the use of PPARγ activators as therapeutic agents in neurodegenerative diseases. PMID:23741474

  9. A role for myosin VI in the localization of axonal proteins.

    Directory of Open Access Journals (Sweden)

    Tommy L Lewis

    2011-03-01

    Full Text Available In neurons polarized trafficking of vesicle-bound membrane proteins gives rise to the distinct molecular composition and functional properties of axons and dendrites. Despite their central role in shaping neuronal form and function, surprisingly little is known about the molecular processes that mediate polarized targeting of neuronal proteins. Recently, the plus-end-directed motor Myosin Va was shown to play a critical role in targeting of transmembrane proteins to dendrites; however, the role of myosin motors in axonal targeting is unknown. Here we show that Myosin VI, a minus-end-directed motor, plays a vital role in the enrichment of proteins on the surface of axons. Engineering non-neuronal proteins to interact with Myosin VI causes them to become highly concentrated at the axonal surface in dissociated rat cortical neurons. Furthermore, disruption of either Myosin VI function or expression leads to aberrant dendritic localization of axonal proteins. Myosin VI mediates the enrichment of proteins on the axonal surface at least in part by stimulating dendrite-specific endocytosis, a mechanism that has been shown to underlie the localization of many axonal proteins. In addition, a version of Channelrhodopsin 2 that was engineered to bind to Myosin VI is concentrated at the surface of the axon of cortical neurons in mice in vivo, suggesting that it could be a useful tool for probing circuit structure and function. Together, our results indicate that myosins help shape the polarized distributions of both axonal and dendritic proteins.

  10. Regulation of axon guidance by compartmentalized nonsense-mediated mRNA decay

    DEFF Research Database (Denmark)

    Colak, Dilek; Ji, Sheng-Jian; Porse, Bo T

    2013-01-01

    show that Robo3.2, a receptor for the Slit family of guidance cues, is synthesized locally within axons of commissural neurons. Robo3.2 translation is induced by floor-plate-derived signals as axons cross the spinal cord midline. Robo3.2 is also a predicted target of the nonsense-mediated mRNA decay...... (NMD) pathway. We find that NMD regulates Robo3.2 synthesis by inducing the degradation of Robo3.2 transcripts in axons that encounter the floor plate. Commissural neurons deficient in NMD proteins exhibit aberrant axonal trajectories after crossing the midline, consistent with misregulation of Robo3...

  11. N-Propionylmannosamine stimulates axonal elongation in a murine model of sciatic nerve injury

    Directory of Open Access Journals (Sweden)

    Christian Witzel

    2015-01-01

    Full Text Available Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modified in vitro as well as in vivo using metabolic oligosaccharide engineering of the N-acyl side chain. N-Propionylmannosamine (ManNProp increases neurite outgrowth and accelerates the reestablishment of functional synapses in vitro. We investigated the influence of systemic ManNProp application using a specific in vivo mouse model. Using mice expressing axonal fluorescent proteins, we quantified the extension of regenerating axons, the number of regenerating axons, the number of arborising axons and the number of branches per axon 5 days after injury. Sciatic nerves from non-expressing mice were grafted into those expressing yellow fluorescent protein. We began a twice-daily intraperitoneal application of either peracetylated ManNProp (200 mg/kg or saline solution 5 days before injury, and continued it until nerve harvest (5 days after transection. ManNProp significantly increased the mean distance of axonal regeneration (2.49 mm vs. 1.53 mm; P < 0.005 and the number of arborizing axons (21% vs. 16% P = 0.008 5 days after sciatic nerve grafting. ManNProp did not affect the number of regenerating axons or the number of branches per arborizing axon. The biochemical glycoengineering of the N-acyl side chain of sialic acid might be a promising approach for improving peripheral nerve regeneration.

  12. Motor neuron synapse and axon defects in a C. elegans alpha-tubulin mutant.

    Directory of Open Access Journals (Sweden)

    Renee Baran

    Full Text Available Regulation of microtubule dynamics underlies many fundamental cellular mechanisms including cell division, cell motility, and transport. In neurons, microtubules play key roles in cell migration, axon outgrowth, control of axon and synapse growth, and the regulated transport of vesicles and structural components of synapses. Loss of synapse and axon integrity and disruption of axon transport characterize many neurodegenerative diseases. Recently, mutations that specifically alter the assembly or stability of microtubules have been found to directly cause neurodevelopmental defects or neurodegeneration in vertebrates. We report here the characterization of a missense mutation in the C-terminal domain of C. elegans alpha-tubulin, tba-1(ju89, that disrupts motor neuron synapse and axon development. Mutant ju89 animals exhibit reduction in the number and size of neuromuscular synapses, altered locomotion, and defects in axon extension. Although null mutations of tba-1 show a nearly wild-type pattern, similar axon outgrowth defects were observed in animals lacking the beta-tubulin TBB-2. Genetic analysis reveals that tba-1(ju89 affects synapse development independent of its role in axon outgrowth. tba-1(ju89 is an altered function allele that most likely perturbs interactions between TBA-1 and specific microtubule-associated proteins that control microtubule dynamics and transport of components needed for synapse and axon growth.

  13. Odorant receptors regulate the final glomerular coalescence of olfactory sensory neuron axons.

    Science.gov (United States)

    Rodriguez-Gil, Diego J; Bartel, Dianna L; Jaspers, Austin W; Mobley, Arie S; Imamura, Fumiaki; Greer, Charles A

    2015-05-05

    Odorant receptors (OR) are strongly implicated in coalescence of olfactory sensory neuron (OSN) axons and the formation of olfactory bulb (OB) glomeruli. However, when ORs are first expressed relative to basal cell division and OSN axon extension is unknown. We developed an in vivo fate-mapping strategy that enabled us to follow OSN maturation and axon extension beginning at basal cell division. In parallel, we mapped the molecular development of OSNs beginning at basal cell division, including the onset of OR expression. Our data show that ORs are first expressed around 4 d following basal cell division, 24 h after OSN axons have reached the OB. Over the next 6+ days the OSN axons navigate the OB nerve layer and ultimately coalesce in glomeruli. These data provide a previously unidentified perspective on the role of ORs in homophilic OSN axon adhesion and lead us to propose a new model dividing axon extension into two phases. Phase I is OR-independent and accounts for up to 50% of the time during which axons approach the OB and begin navigating the olfactory nerve layer. Phase II is OR-dependent and concludes as OSN axons coalesce in glomeruli.

  14. NMNAT1 inhibits axon degeneration via blockade of SARM1-mediated NAD+ depletion

    Science.gov (United States)

    Sasaki, Yo; Nakagawa, Takashi; Mao, Xianrong; DiAntonio, Aaron; Milbrandt, Jeffrey

    2016-01-01

    Overexpression of the NAD+ biosynthetic enzyme NMNAT1 leads to preservation of injured axons. While increased NAD+ or decreased NMN levels are thought to be critical to this process, the mechanism(s) of this axon protection remain obscure. Using steady-state and flux analysis of NAD+ metabolites in healthy and injured mouse dorsal root ganglion axons, we find that rather than altering NAD+ synthesis, NMNAT1 instead blocks the injury-induced, SARM1-dependent NAD+ consumption that is central to axon degeneration. DOI: http://dx.doi.org/10.7554/eLife.19749.001 PMID:27735788

  15. Evidence for the Role of MAP1B in Axon Formation

    Science.gov (United States)

    Gonzalez-Billault, Christian; Avila, Jesus; Cáceres, Alfredo

    2001-01-01

    Cultured neurons obtained from a hypomorphous MAP1B mutant mouse line display a selective and significant inhibition of axon formation that reflects a delay in axon outgrowth and a reduced rate of elongation. This phenomenon is paralleled by decreased microtubule formation and dynamics, which is dramatic at the distal axonal segment, as well as in growth cones, where the more recently assembled microtubule polymer normally predominates. These neurons also have aberrant growth cone formation and increased actin-based protrusive activity. Taken together, this study provides direct evidence showing that by promoting microtubule dynamics and regulating cytoskeletal organization MAP1B has a crucial role in axon formation. PMID:11452005

  16. Biomarker evidence of axonal injury in neuroasymptomatic HIV-1 patients.

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    Jan Jessen Krut

    Full Text Available Prevalence of neurocognitive impairment in HIV-1 infected patients is reported to be high. Whether this is a result of active HIV-related neurodegeneration is unclear. We examined axonal injury in HIV-1 patients by measuring the light subunit of neurofilament protein (NFL in CSF with a novel, sensitive method.With a cross-sectional design, CSF concentrations of neurofilament protein light (NFL (marker of neuronal injury, neopterin (intrathecal immunoactivation and CSF/Plasma albumin ratio (blood-brain barrier integrity were analyzed on CSF from 252 HIV-infected patients, subdivided into untreated neuroasymptomatics (n = 200, HIV-associated dementia (HAD (n = 14 and on combinations antiretroviral treatment (cART (n = 85, and healthy controls (n = 204. 46 HIV-infected patients were included in both treated and untreated groups, but sampled at different timepoints. Furthermore, 78 neuroasymptomatic patients were analyzed before and after treatment initiation.While HAD patients had the highest NFL concentrations, elevated CSF NFL was also found in 33% of untreated neuroasymptomatic patients, mainly in those with blood CD4+ cell counts below 250 cells/μL. CSF NFL concentrations in the untreated neuroasymptomatics and treated groups were equivalent to controls 18.5 and 3.9 years older, respectively. Neopterin correlated with NFL levels in untreated groups while the albumin ratio correlated with NFL in both untreated and treated groups.Increased CSF NFL indicates ongoing axonal injury in many neuroasymptomatic patients. Treatment decreases NFL, but treated patients retain higher levels than controls, indicating either continued virus-related injury or an aging-like effect of HIV infection. NFL correlates with neopterin and albumin ratio, suggesting an association between axonal injury, neuroinflammation and blood-brain barrier permeability. NFL appears to be a sensitive biomarker of subclinical and clinical brain injury in HIV and warrants further

  17. Erbin is required for myelination in regenerated axons after injury

    OpenAIRE

    2012-01-01

    Neuregulin 1 (NRG1) is an axon-derived factor that is critical for Schwann cell (SC) development and myelinogenesis in a manner dependent on transmembrane tyrosine kinases ErbB2 and ErbB3. Recent studies suggest that NRG1 signaling plays a role in remyelination of regenerated nerves after injury. In this study, we investigated the role of Erbin, a protein that interacts with ErbB2 in remyelination of injured nerves. We show that Erbin expression increased dramatically in injured nerves. Myeli...

  18. Pyridoxine neuropathy in rats: specific degeneration of sensory axons.

    Science.gov (United States)

    Windebank, A J; Low, P A; Blexrud, M D; Schmelzer, J D; Schaumburg, H H

    1985-11-01

    When rats received pyridoxine in doses large enough to cause neuropathy in humans, the animals developed gait ataxia that subsided after the toxin was withdrawn. By using quantitative histologic techniques, we found axonal degeneration of sensory system fibers and that the fibers derived from the ventral root were spared. Although the degeneration approached the dorsal root ganglion, neurons in the ganglion did not degenerate. We found no early decrease in oxygen consumption of nerve, suggesting that impaired oxidative metabolism was not the primary event.

  19. Neuroprotective Effects of Citicoline in Diffuse Axonal Injuries

    OpenAIRE

    Firooz Salehpou; Ghaffar Shokouhi; Moslem Shakeri; Mohammad Shimia; Atta Mahdkhah; Ali Baradaran; Mohammad Taghi Imani; arhad Mirzaee; Aydin Kazempour Azar; Amir Mohammad Bazzazi; Hadi Mohammad Khanli

    2013-01-01

    Citicoline is a neuroprotective agent and fundamental item of phospholipid biosynthesis in cell walls. In this study, we aimed at examining the effect of citicoline in patients suffering from traumatic brain injury with Glasgow Coma Score (GCS) ≤ 8, and diffuse axonal injury (DAI) diagnosis. Efficacy of citicoline was evaluated by measurement of malondialdehyde (MDA) plasma levels as a marker of oxidative stress. Forty patients were randomly divided into two groups of cases (treated with citi...

  20. Neuropatía hemorrágica tóxica aguda y fallo multiorgánico tras intoxicación por anticoagulantes, disolventes, AINES y antihistamínicos: A propósito de un caso fatal Acute toxic haemorrhagic neuropathy and multiorganic failure following poisoning by anticoagulants, solvents, nsaids and antihistaminic drugs: Report of a fatal case

    Directory of Open Access Journals (Sweden)

    A. Garfia

    2002-01-01

    Full Text Available Se presenta un caso de intoxicación mortal por ingestión del raticida Brodifacum, un anticoagulante superwarfarínico, junto con otros fármacos, entre los que se incluían antiinflamatorios no esteroideos y un disolvente orgánico de uso doméstico. El sujeto falleció en la UCI, con un cuadro de insuficiencia respiratoria aguda, seguida de fallo hepático y renal. En la autopsia se pusieron de manifiesto lesiones hemorrágicas circunferenciales que afectaban a diversos tejidos, entre los que se encontraban la grasa mesentérica, el epicardio, y la grasa perirrenal. El estudio microscópico demostró la existencia de una típica lesión hemorrágica aguda, circunferencial, en los nervios vegetativos epicárdicos y del área del esplácnico. La explicación de porqué los nervios periféricos vegetativos se constituyen en diana de los efectos tóxicos se atribuye a la acción combinada de los disolventes y de los anticoagulantes, sobre el sistema nervioso periférico. Se sabe que los disolventes orgánicos producen una lesión neuronal aguda, consistente en tumefacción axonal y del soma neuronal, que conlleva a la alteración del sistema de transporte a lo largo del axón. Creemos que -desde el punto de vista fisiopatológico- la vasodilatación reactiva de los vasa nervorum, producida a consecuencia de la lesión neuronal aguda inducida por los disolventes, unida al estado de hipocoagulabilidad sanguínea -dependiente de la ingestión de Brodifacum (superwarfarina y potenciada por los antiinflamatorios no esteroideos- constituyen los mecanismos íntimos que podrían explicar esta peculiar Neuropatía Hemorrágica Aguda Tóxica de los nervios periféricos del Sistema Nervioso Neurovegetativo. Desconocemos si los nervios periféricos mixtos se encontraban afectados por esta lesión, al carecer de muestras para un estudio definitivo.In this paper we describe a case of mortal poisoning by ingestion of the rodenticide Brodifacoum, a superwarfarin

  1. Abnormal morphology of myelin and axon pathology in murine models of multiple sclerosis.

    Science.gov (United States)

    Bando, Yoshio; Nomura, Taichi; Bochimoto, Hiroki; Murakami, Koichi; Tanaka, Tatsuhide; Watanabe, Tsuyoshi; Yoshida, Shigetaka

    2015-02-01

    Demyelination and axonal damage are responsible for neurological deficits in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system. However, the pathology of axonal damage in MS is not fully understood. In this study, histological analysis of morphological changes of axonal organelles during demyelination in murine models was investigated by scanning electron microscopy (SEM) using an osmium-maceration method. In cuprizone-induced demyelination, SEM showed typical morphology of demyelination in the corpus callosum of mouse brain. In contrast, SEM displayed variations in ultrastructural abnormalities of myelin structures and axonal organelles in spinal cord white matter of experimental autoimmune encephalomyelitis (EAE) mice, an animal model of MS. Myelin detachment and excessive myelin formation were observed as typical morphological myelin abnormalities in EAE. In addition, well-developed axoplasmic reticulum-like structures and accumulated mitochondria were observed in tortuous degenerating/degenerated axons and the length of mitochondria in axons of EAE spinal cord was shorter compared with naïve spinal cord. Immunohistochemistry also revealed dysfunction of mitochondrial fusion/fission machinery in EAE spinal cord axons. Moreover, the number of Y-shaped mitochondria was significantly increased in axons of the EAE spinal cord. Axonal morphologies in myelin basic protein-deficient shiverer mice were similar to those in EAE. However, shiverer mice had "tortuous" (S-curve shaped mitochondria) and larger mitochondria compared with wild-type and EAE mice. Lastly, analysis of human MS patient autopsied brains also demonstrated abnormal myelin structures in demyelinating lesions. These results indicate that morphological abnormalities of myelin and axonal organelles play important role on the pathogenesis of axonal injury in demyelinating diseases.

  2. Plexin A3 and turnout regulate motor axonal branch morphogenesis in zebrafish.

    Directory of Open Access Journals (Sweden)

    Rajiv Sainath

    Full Text Available During embryogenesis motor axons navigate to their target muscles, where individual motor axons develop complex branch morphologies. The mechanisms that control axonal branching morphogenesis have been studied intensively, yet it still remains unclear when branches begin to form or how branch locations are determined. Live cell imaging of individual zebrafish motor axons reveals that the first axonal branches are generated at the ventral extent of the myotome via bifurcation of the growth cone. Subsequent branches are generated by collateral branching restricted to their synaptic target field along the distal portion of the axon. This precisely timed and spatially restricted branching process is disrupted in turnout mutants we identified in a forward genetic screen. Molecular genetic mapping positioned the turnout mutation within a 300 kb region encompassing eight annotated genes, however sequence analysis of all eight open reading frames failed to unambiguously identify the turnout mutation. Chimeric analysis and single cell labeling reveal that turnout function is required cell non-autonomously for intraspinal motor axon guidance and peripheral branch formation. turnout mutant motor axons form the first branch on time via growth cone bifurcation, but unlike wild-type they form collateral branches precociously, when the growth cone is still navigating towards the ventral myotome. These precocious collateral branches emerge along the proximal region of the axon shaft typically devoid of branches, and they develop into stable, permanent branches. Furthermore, we find that null mutants of the guidance receptor plexin A3 display identical motor axon branching defects, and time lapse analysis reveals that precocious branch formation in turnout and plexin A3 mutants is due to increased stability of otherwise short-lived axonal protrusions. Thus, plexin A3 dependent intrinsic and turnout dependent extrinsic mechanisms suppress collateral branch

  3. RabGDI controls axonal midline crossing by regulating Robo1 surface expression

    Directory of Open Access Journals (Sweden)

    Philipp Melanie

    2012-11-01

    Full Text Available Abstract Background Axons navigate to their future synaptic targets with the help of choice points, intermediate targets that express axon guidance cues. Once they reach a choice point, axons need to switch their response from attraction to repulsion in order to move on with the next stage of their journey. The mechanisms underlying the change in axonal responsiveness are poorly understood. Commissural axons become sensitive to the repulsive activity of Slits when they cross the ventral midline of the CNS. Responsiveness to Slits depends on surface expression of Robo receptors. In Drosophila, Commissureless (Comm plays a crucial regulatory role in midline crossing by keeping Robo levels low on precommissural axons. Interestingly, to date no vertebrate homolog of comm has been identified. Robo3/Rig1 has been shown to control Slit sensitivity before the midline, but without affecting Robo1 surface expression. Results We had identified RabGDI, a gene linked to human mental retardation and an essential component of the vesicle fusion machinery, in a screen for differentially expressed floor-plate genes. Downregulation of RabGDI by in ovo RNAi caused commissural axons to stall in the floor plate, phenocopying the effect observed after downregulation of Robo1. Conversely, premature expression of RabGDI prevented commissural axons from entering the floor plate. Furthermore, RabGDI triggered Robo1 surface expression in cultured commissural neurons. Taken together, our results identify RabGDI as a component of the switching mechanism that is required for commissural axons to change their response from attraction to repulsion at the intermediate target. Conclusion RabGDI takes over the functional role of fly Comm by regulating the surface expression of Robo1 on commissural axons in vertebrates. This in turn allows commissural axons to switch from attraction to repulsion at the midline of the spinal cord.

  4. A possible role for integrin signaling in diffuse axonal injury.

    Directory of Open Access Journals (Sweden)

    Matthew A Hemphill

    Full Text Available Over the past decade, investigators have attempted to establish the pathophysiological mechanisms by which non-penetrating injuries damage the brain. Several studies have implicated either membrane poration or ion channel dysfunction pursuant to neuronal cell death as the primary mechanism of injury. We hypothesized that traumatic stimulation of integrins may be an important etiological contributor to mild Traumatic Brain Injury. In order to study the effects of forces at the cellular level, we utilized two hierarchical, in vitro systems to mimic traumatic injury to rat cortical neurons: a high velocity stretcher and a magnetic tweezer system. In one system, we controlled focal adhesion formation in neurons cultured on a stretchable substrate loaded with an abrupt, one dimensional strain. With the second system, we used magnetic tweezers to directly simulate the abrupt injury forces endured by a focal adhesion on the neurite. Both systems revealed variations in the rate and nature of neuronal injury as a function of focal adhesion density and direct integrin stimulation without membrane poration. Pharmacological inhibition of calpains did not mitigate the injury yet the inhibition of Rho-kinase immediately after injury reduced axonal injury. These data suggest that integrin-mediated activation of Rho may be a contributor to the diffuse axonal injury reported in mild Traumatic Brain Injury.

  5. An analysis of conductance changes in squid axon.

    Science.gov (United States)

    MULLINS, L J

    1959-05-20

    The membrane of the squid axon is considered on the basis of a pore model in which the distribution of the pore sizes strongly favors K(+) transfer when there is no potential. Electrical asymmetry causes non-penetrating ions on the membrane capacitor to exert a mechanical force on both membrane surfaces and this force results in a deformation of the membrane pore system such that it assumes a distribution of sizes favoring the ions exerting mechanical force. The ions involved appear to be Ca(++) on the outside of the membrane and isethionate(-), (i(-)) on the inside; as Ca(++) is equivalent in size to Na(+), the charged membrane is potentially able to transfer Na(+), when the ions deforming the membrane pore distribution are removed. A depolarization of the membrane leads to an opening of pores that will allow Na(+) penetration and a release of the membrane from deformation. The pores revert to the zero-potential pore size distribution hence the Na permeability change is a transient. Calculation shows that the potassium conductance vs. displacement of membrane potential curve for the squid axon and the "inactivation" function, h, can be obtained directly from the assumed membrane distortion without the introduction of arbitrary parameters. The sodium conductance, because it is a transient, requires assumptions about the time constants with which ions unblock pores at the outside and the inside of the membrane.

  6. Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes.

    Science.gov (United States)

    Biankin, Andrew V; Waddell, Nicola; Kassahn, Karin S; Gingras, Marie-Claude; Muthuswamy, Lakshmi B; Johns, Amber L; Miller, David K; Wilson, Peter J; Patch, Ann-Marie; Wu, Jianmin; Chang, David K; Cowley, Mark J; Gardiner, Brooke B; Song, Sarah; Harliwong, Ivon; Idrisoglu, Senel; Nourse, Craig; Nourbakhsh, Ehsan; Manning, Suzanne; Wani, Shivangi; Gongora, Milena; Pajic, Marina; Scarlett, Christopher J; Gill, Anthony J; Pinho, Andreia V; Rooman, Ilse; Anderson, Matthew; Holmes, Oliver; Leonard, Conrad; Taylor, Darrin; Wood, Scott; Xu, Qinying; Nones, Katia; Fink, J Lynn; Christ, Angelika; Bruxner, Tim; Cloonan, Nicole; Kolle, Gabriel; Newell, Felicity; Pinese, Mark; Mead, R Scott; Humphris, Jeremy L; Kaplan, Warren; Jones, Marc D; Colvin, Emily K; Nagrial, Adnan M; Humphrey, Emily S; Chou, Angela; Chin, Venessa T; Chantrill, Lorraine A; Mawson, Amanda; Samra, Jaswinder S; Kench, James G; Lovell, Jessica A; Daly, Roger J; Merrett, Neil D; Toon, Christopher; Epari, Krishna; Nguyen, Nam Q; Barbour, Andrew; Zeps, Nikolajs; Kakkar, Nipun; Zhao, Fengmei; Wu, Yuan Qing; Wang, Min; Muzny, Donna M; Fisher, William E; Brunicardi, F Charles; Hodges, Sally E; Reid, Jeffrey G; Drummond, Jennifer; Chang, Kyle; Han, Yi; Lewis, Lora R; Dinh, Huyen; Buhay, Christian J; Beck, Timothy; Timms, Lee; Sam, Michelle; Begley, Kimberly; Brown, Andrew; Pai, Deepa; Panchal, Ami; Buchner, Nicholas; De Borja, Richard; Denroche, Robert E; Yung, Christina K; Serra, Stefano; Onetto, Nicole; Mukhopadhyay, Debabrata; Tsao, Ming-Sound; Shaw, Patricia A; Petersen, Gloria M; Gallinger, Steven; Hruban, Ralph H; Maitra, Anirban; Iacobuzio-Donahue, Christine A; Schulick, Richard D; Wolfgang, Christopher L; Morgan, Richard A; Lawlor, Rita T; Capelli, Paola; Corbo, Vincenzo; Scardoni, Maria; Tortora, Giampaolo; Tempero, Margaret A; Mann, Karen M; Jenkins, Nancy A; Perez-Mancera, Pedro A; Adams, David J; Largaespada, David A; Wessels, Lodewyk F A; Rust, Alistair G; Stein, Lincoln D; Tuveson, David A; Copeland, Neal G; Musgrove, Elizabeth A; Scarpa, Aldo; Eshleman, James R; Hudson, Thomas J; Sutherland, Robert L; Wheeler, David A; Pearson, John V; McPherson, John D; Gibbs, Richard A; Grimmond, Sean M

    2012-11-15

    Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis.

  7. Bushen Yisui Capsule ameliorates axonal injury in experimental autoimmune encephalomyelitis

    Institute of Scientific and Technical Information of China (English)

    Ling Fang; Lei Wang; Qi Zheng; Tao Yang; Hui Zhao; Qiuxia Zhang; Kangning Li; Li Zhou; Haiyang Gong; Yongping Fan

    2013-01-01

    A preliminary clinical study by our group demonstrated Bushen Yisui Capsule (formerly cal ed Er-huang Formula) in combination with conventional therapy is an effective prescription for the treat-ment of multiple sclerosis. However, its effect on axonal injury during early multiple sclerosis re-mains unclear. In this study, a MOG 35-55-immunized C57BL/6 mouse model of experimental au-toimmune encephalomyelitis was intragastrical y administered Bushen Yisui Capsule. The results showed that Bushen Yisui Capsule effectively improved clinical symptoms and neurological function of experimental autoimmune encephalomyelitis. In addition, amyloid precursor protein expression was down-regulated and microtubule-associated protein 2 was up-regulated. Experimental findings indicate that the disease-preventive mechanism of Bushen Yisui Capsule in experimental autoim-mune encephalomyelitis was mediated by amelioration of axonal damage and promotion of rege-neration. But the effects of the high-dose Bushen Yisui Capsule group was not better than that of the medium-dose and low-dose Bushen Yisui Capsule group in preventing neurological dysfunction.

  8. Tau phosphorylation affects its axonal transport and degradation

    Science.gov (United States)

    Rodríguez-Martín, Teresa; Cuchillo-Ibáñez, Inmaculada; Noble, Wendy; Nyenya, Fanon; Anderton, Brian H.; Hanger, Diane P.

    2013-01-01

    Phosphorylated forms of microtubule-associated protein tau accumulate in neurofibrillary tangles in Alzheimer's disease. To investigate the effects of specific phosphorylated tau residues on its function, wild type or phosphomutant tau was expressed in cells. Elevated tau phosphorylation decreased its microtubule binding and bundling, and increased the number of motile tau particles, without affecting axonal transport kinetics. In contrast, reducing tau phosphorylation enhanced the amount of tau bound to microtubules and inhibited axonal transport of tau. To determine whether differential tau clearance is responsible for the increase in phosphomimic tau, we inhibited autophagy in neurons which resulted in a 3-fold accumulation of phosphomimic tau compared with wild type tau, and endogenous tau was unaffected. In autophagy-deficient mouse embryonic fibroblasts, but not in neurons, proteasomal degradation of phosphomutant tau was also reduced compared with wild type tau. Therefore, autophagic and proteasomal pathways are involved in tau degradation, with autophagy appearing to be the primary route for clearing phosphorylated tau in neurons. Defective autophagy might contribute to the accumulaton of tau in neurodegenerative diseases. PMID:23601672

  9. Selective optogenetic stimulation of cholinergic axons in neocortex.

    Science.gov (United States)

    Kalmbach, Abigail; Hedrick, Tristan; Waters, Jack

    2012-04-01

    Acetylcholine profoundly affects neocortical function, being involved in arousal, attention, learning, memory, sensory and motor function, and plasticity. The majority of cholinergic afferents to neocortex are from neurons in nucleus basalis. Nucleus basalis also contains projecting neurons that release other transmitters, including GABA and possibly glutamate. Hence, electrical stimulation of nucleus basalis evokes the release of a mixture of neurotransmitters in neocortex, and this lack of selectivity has impeded research on cholinergic signaling in neocortex. We describe a method for the selective stimulation of cholinergic axons in neocortex. We used the Cre-lox system and a viral vector to express the light-activated protein channelrhodopsin-2 in cholinergic neurons in nucleus basalis and their axons in neocortex. Labeled neurons depolarized on illumination with blue light but were otherwise unchanged. In anesthetized mice, illumination of neocortex desynchronized the local field potential, indicating that light evoked release of ACh. This novel technique will enable many new studies of the cellular, network, and behavioral physiology of ACh in neocortex.

  10. Celulitis por citomegalovirus

    Directory of Open Access Journals (Sweden)

    A. Ruiz Lascano

    2002-12-01

    Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.

  11. Shank3 is localized in axons and presynaptic specializations of developing hippocampal neurons and involved in the modulation of NMDA receptor levels at axon terminals.

    Science.gov (United States)

    Halbedl, Sonja; Schoen, Michael; Feiler, Marisa S; Boeckers, Tobias M; Schmeisser, Michael J

    2016-04-01

    Autism-related Shank1, Shank2, and Shank3 are major postsynaptic scaffold proteins of excitatory glutamatergic synapses. A few studies, however, have already indicated that within a neuron, the presence of Shank family members is not limited to the postsynaptic density. By separating axons from dendrites of developing hippocampal neurons in microfluidic chambers, we show that RNA of all three Shank family members is present within axons. Immunostaining confirms these findings as all three Shanks are indeed found within separated axons and further co-localize with well-known proteins of the presynaptic specialization in axon terminals. Therefore, Shank proteins might not only serve as postsynaptic scaffold proteins, but also play a crucial role during axonal outgrowth and presynaptic development and function. This is supported by our findings that shRNA-mediated knockdown of Shank3 results in up-regulation of the NMDA receptor subunit GluN1 in axon terminals. Taken together, our findings will have major implications for the future analysis of neuronal Shank biology in both health and disease. Shank1, Shank2, and Shank3 are major postsynaptic scaffold proteins of excitatory glutamatergic synapses strongly related to several neuropsychiatric disorders. However, a few studies have already implicated a functional role of the Shanks beyond the postsynaptic density (PSD). We here show that all three Shanks are localized in both axons and pre-synaptic specializiations of developing hippocampal neurons in culture. We further provide evidence that Shank3 is involved in the modulation of NMDA receptor levels at axon terminals. Taken together, our study will open up novel avenues for the future analysis of neuronal Shank biology in both health and disease.

  12. Sensory axon-derived neuregulin-1 is required for axoglial signaling and normal sensory function but not for long-term axon maintenance

    DEFF Research Database (Denmark)

    Fricker, F.R.; Zhu, N.; Tsantoulas, C.

    2009-01-01

    death; the markers of different DRG cell populations and cutaneous innervation were unchanged. These anatomical changes were reflected in a slowing of conduction velocity at the lower end of the A-fiber conduction velocity range and a new population of more rapidly conducting C-fibers that are likely...... cells required for normal sensory function. Sensory neuronal survival and axonal maintenance, however, are not dependent on axon-derived neuregulin-1 signaling in adulthood Udgivelsesdato: 2009/6/17...

  13. N-docosahexaenoylethanolamine regulates Hedgehog signaling and promotes growth of cortical axons

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    Giorgi Kharebava

    2015-12-01

    Full Text Available Axonogenesis, a process for the establishment of neuron connectivity, is central to brain function. The role of metabolites derived from docosahexaenoic acid (DHA, 22:6n-3 that is specifically enriched in the brain, has not been addressed in axon development. In this study, we tested if synaptamide (N-docosahexaenoylethanolamine, an endogenous metabolite of DHA, affects axon growth in cultured cortical neurons. We found that synaptamide increased the average axon length, inhibited GLI family zinc finger 1 (GLI1 transcription and sonic hedgehog (Shh target gene expression while inducing cAMP elevation. Similar effects were produced by cyclopamine, a regulator of the Shh pathway. Conversely, Shh antagonized elevation of cAMP and blocked synaptamide-mediated increase in axon length. Activation of Shh pathway by a smoothened (SMO agonist (SAG or overexpression of SMO did not inhibit axon growth mediated by synaptamide or cyclopamine. Instead, adenylate cyclase inhibitor SQ22536 abolished synaptamide-mediated axon growth indicating requirement of cAMP elevation for this process. Our findings establish that synaptamide promotes axon growth while Shh antagonizes synaptamide-mediated cAMP elevation and axon growth by a SMO-independent, non-canonical pathway.

  14. Axon-somatic back-propagation in detailed models of spinal alpha motoneurons

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    Pietro eBalbi

    2015-02-01

    Full Text Available Antidromic action potentials following distal stimulation of motor axons occasionally fail to invade the soma of alpha motoneurons in spinal cord, due to their passing through regions of high non-uniformity.Morphologically detailed conductance-based models of cat spinal alpha motoneurons have been developed, with the aim to reproduce and clarify some aspects of the electrophysiological behavior of the antidromic axon-somatic spike propagation. Fourteen 3D morphologically detailed somata and dendrites of cat spinal alpha motoneurons have been imported from an open-access web-based database of neuronal morphologies, NeuroMorpho.org, and instantiated in neurocomputational models. An axon hillock, an axonal initial segment and a myelinated axon are added to each model.By sweeping the diameter of the axonal initial segment (AIS and the axon hillock, as well as the maximal conductances of sodium channels at the AIS and at the soma, the developed models are able to show the relationships between different geometric and electrophysiological configurations and the voltage attenuation of the antidromically travelling wave.In particular, a greater than usually admitted sodium conductance at AIS is necessary and sufficient to overcome the dramatic voltage attenuation occurring during antidromic spike propagation both at the myelinated axon-AIS and at the AIS-soma transitions.

  15. Axonal transport rate decreased at the onset of optic neuritis in EAE mice.

    Science.gov (United States)

    Lin, Tsen-Hsuan; Kim, Joong Hee; Perez-Torres, Carlos; Chiang, Chia-Wen; Trinkaus, Kathryn; Cross, Anne H; Song, Sheng-Kwei

    2014-10-15

    Optic neuritis is frequently the first symptom of multiple sclerosis (MS), an inflammatory demyelinating neurodegenerative disease. Impaired axonal transport has been considered as an early event of neurodegenerative diseases. However, few studies have assessed the integrity of axonal transport in MS or its animal models. We hypothesize that axonal transport impairment occurs at the onset of optic neuritis in experimental autoimmune encephalomyelitis (EAE) mice. In this study, we employed manganese-enhanced MRI (MEMRI) to assess axonal transport in optic nerves in EAE mice at the onset of optic neuritis. Axonal transport was assessed as (a) optic nerve Mn(2+) accumulation rate (in % signal change/h) by measuring the rate of increased total optic nerve signal enhancement, and (b) Mn(2+) transport rate (in mm/h) by measuring the rate of change in optic nerve length enhanced by Mn(2+). Compared to sham-treated healthy mice, Mn(2+) accumulation rate was significantly decreased by 19% and 38% for EAE mice with moderate and severe optic neuritis, respectively. The axonal transport rate of Mn(2+) was significantly decreased by 43% and 65% for EAE mice with moderate and severe optic neuritis, respectively. The degree of axonal transport deficit correlated with the extent of impaired visual function and diminished microtubule-associated tubulins, as well as the severity of inflammation, demyelination, and axonal injury at the onset of optic neuritis.

  16. Inhibition of kinesin-5 improves regeneration of injured axons by a novel microtubule-based mechanism

    Institute of Scientific and Technical Information of China (English)

    Peter W. Baas; Andrew J. Matamoros

    2015-01-01

    Microtubules have been identiifed as a powerful target for augmenting regeneration of injured adult axons in the central nervous system. Drugs that stabilize microtubules have shown some promise, but there are concerns that abnormally stabilizing microtubules may have only limited beneifts for regeneration, while at the same time may be detrimental to the normal work that microtubules perform for the axon. Kinesin-5 (also called kif11 or Eg5), a molecular motor protein best known for its crucial role in mitosis, acts as a brake on microtubule movements by other motor proteins in the axon. Drugs that inhibit kinesin-5, originally developed to treat cancer, result in greater mobility of microtubules in the axon and an overall shift in the forces on the microtubule array. As a result, the axon grows faster, retracts less, and more readily enters environments that are inhibitory to axonal regeneration. Thus, drugs that inhibit kinesin-5 offer a novel microtubule-based means to boost axonal regeneration without the concerns that ac-company abnormal stabilization of the microtubule array. Even so, inhibiting kinesin-5 is not without its own caveats, such as potential problems with navigation of the regenerating axon to its target, as well as morphological effects on dendrites that could affect learning and memory if the drugs reach the brain.

  17. Selective vulnerability and pruning of phasic motoneuron axons in motoneuron disease alleviated by CNTF.

    Science.gov (United States)

    Pun, San; Santos, Alexandre Ferrão; Saxena, Smita; Xu, Lan; Caroni, Pico

    2006-03-01

    Neurodegenerative diseases can have long preclinical phases and insidious progression patterns, but the mechanisms of disease progression are poorly understood. Because quantitative accounts of neuronal circuitry affected by disease have been lacking, it has remained unclear whether disease progression reflects processes of stochastic loss or temporally defined selective vulnerabilities of distinct synapses or axons. Here we derive a quantitative topographic map of muscle innervation in the hindlimb. We show that in two mouse models of motoneuron disease (G93A SOD1 and G85R SOD1), axons of fast-fatiguable motoneurons are affected synchronously, long before symptoms appear. Fast-fatigue-resistant motoneuron axons are affected at symptom-onset, whereas axons of slow motoneurons are resistant. Axonal vulnerability leads to synaptic vesicle stalling and accumulation of BC12a1-a, an anti-apoptotic protein. It is alleviated by ciliary neurotrophic factor and triggers proteasome-dependent pruning of peripheral axon branches. Thus, motoneuron disease involves predictable, selective vulnerability patterns by physiological subtypes of axons, episodes of abrupt pruning in the target region and compensation by resistant axons.

  18. Bimodal control of dendritic and axonal growth by the dual leucine zipper kinase pathway.

    Directory of Open Access Journals (Sweden)

    Xin Wang

    Full Text Available Knowledge of the molecular and genetic mechanisms underlying the separation of dendritic and axonal compartments is not only crucial for understanding the assembly of neural circuits, but also for developing strategies to correct defective dendrites or axons in diseases with subcellular precision. Previous studies have uncovered regulators dedicated to either dendritic or axonal growth. Here we investigate a novel regulatory mechanism that differentially directs dendritic and axonal growth within the same neuron in vivo. We find that the dual leucine zipper kinase (DLK signaling pathway in Drosophila, which consists of Highwire and Wallenda and controls axonal growth, regeneration, and degeneration, is also involved in dendritic growth in vivo. Highwire, an evolutionarily conserved E3 ubiquitin ligase, restrains axonal growth but acts as a positive regulator for dendritic growth in class IV dendritic arborization neurons in the larva. While both the axonal and dendritic functions of highwire require the DLK kinase Wallenda, these two functions diverge through two downstream transcription factors, Fos and Knot, which mediate the axonal and dendritic regulation, respectively. This study not only reveals a previously unknown function of the conserved DLK pathway in controlling dendrite development, but also provides a novel paradigm for understanding how neuronal compartmentalization and the diversity of neuronal morphology are achieved.

  19. NF-Protocadherin Regulates Retinal Ganglion Cell Axon Behaviour in the Developing Visual System.

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    Louis C Leung

    Full Text Available Cell adhesion molecules play a central role in mediating axonal tract development within the nascent nervous system. NF-protocadherin (NFPC, a member of the non-clustered protocadherin family, has been shown to regulate retinal ganglion cell (RGC axon and dendrite initiation, as well as influencing axonal navigation within the mid-optic tract. However, whether NFPC mediates RGC axonal behaviour at other positions within the optic pathway remains unclear. Here we report that NFPC plays an important role in RGC axonogenesis, but not in intraretinal guidance. Moreover, axons with reduced NFPC levels exhibit insensitivity to Netrin-1, an attractive guidance cue expressed at the optic nerve head. Netrin-1 induces rapid turnover of NFPC localized to RGC growth cones, suggesting that the regulation of NFPC protein levels may underlie Netrin-1-mediated entry of RGC axons into the optic nerve head. At the tectum, we further reveal a function for NFPC in controlling RGC axonal entry into the final target area. Collectively, our results expand our understanding of the role of NFPC in RGC guidance and illustrate that this adhesion molecule contributes to axon behaviour at multiple points in the optic pathway.

  20. Selective control of small versus large diameter axons using infrared laser light (Conference Presentation)

    Science.gov (United States)

    Lothet, Emilie H.; Shaw, Kendrick M.; Horn, Charles C.; Lu, Hui; Wang, Yves T.; Jansen, E. Duco; Chiel, Hillel J.; Jenkins, Michael W.

    2016-03-01

    Sensory information is conveyed to the central nervous system via small diameter unmyelinated fibers. In general, smaller diameter axons have slower conduction velocities. Selective control of such fibers could create new clinical treatments for chronic pain, nausea in response to chemo-therapeutic agents, or hypertension. Electrical stimulation can control axonal activity, but induced axonal current is proportional to cross-sectional area, so that large diameter fibers are affected first. Physiologically, however, synaptic inputs generally affect small diameter fibers before large diameter fibers (the size principle). A more physiological modality that first affected small diameter fibers could have fewer side effects (e.g., not recruiting motor axons). A novel mathematical analysis of the cable equation demonstrates that the minimum length along the axon for inducing block scales with the square root of axon diameter. This implies that the minimum length along an axon for inhibition will scale as the square root of axon diameter, so that lower radiant exposures of infrared light will selectively affect small diameter, slower conducting fibers before those of large diameter. This prediction was tested in identified neurons from the marine mollusk Aplysia californica. Radiant exposure to block a neuron with a slower conduction velocity (B43) was consistently lower than that needed to block a faster conduction velocity neuron (B3). Furthermore, in the vagus nerve of the musk shrew, lower radiant exposure blocked slow conducting fibers before blocking faster conducting fibers. Infrared light can selectively control smaller diameter fibers, suggesting many novel clinical treatments.

  1. The central role of mitochondria in axonal degeneration in multiple sclerosis.

    Science.gov (United States)

    Campbell, Graham R; Worrall, Joseph T; Mahad, Don J

    2014-12-01

    Neurodegeneration in multiple sclerosis (MS) is related to inflammation and demyelination. In acute MS lesions and experimental autoimmune encephalomyelitis focal immune attacks damage axons by injuring axonal mitochondria. In progressive MS, however, axonal damage occurs in chronically demyelinated regions, myelinated regions and also at the active edge of slowly expanding chronic lesions. How axonal energy failure occurs in progressive MS is incompletely understood. Recent studies show that oligodendrocytes supply lactate to myelinated axons as a metabolic substrate for mitochondria to generate ATP, a process which will be altered upon demyelination. In addition, a number of studies have identified mitochondrial abnormalities within neuronal cell bodies in progressive MS, leading to a deficiency of mitochondrial respiratory chain complexes or enzymes. Here, we summarise the mitochondrial abnormalities evident within neurons and discuss how these grey matter mitochondrial abnormalities may increase the vulnerability of axons to degeneration in progressive MS. Although neuronal mitochondrial abnormalities will culminate in axonal degeneration, understanding the different contributions of mitochondria to the degeneration of myelinated and demyelinated axons is an important step towards identifying potential therapeutic targets for progressive MS.

  2. Axonal pathfinding mechanisms at the cortical midline and in the development of the corpus callosum

    Directory of Open Access Journals (Sweden)

    Richards L.J.

    2002-01-01

    Full Text Available The corpus callosum is a large fiber tract that connects neurons in the right and left cerebral hemispheres. Agenesis of the corpus callosum (ACC is associated with a large number of human syndromes but little is known about why ACC occurs. In most cases of ACC, callosal axons are able to grow toward the midline but are unable to cross it, continuing to grow into large swirls of axons known as Probst bundles. This phenotype suggests that in some cases ACC may be due to defects in axonal guidance at the midline. General guidance mechanisms that influence the development of axons include chemoattraction and chemorepulsion, presented by either membrane-bound or diffusible molecules. These molecules are not only expressed by the final target but by intermediate targets along the pathway, and by pioneering axons that act as guides for later arriving axons. Midline glial populations are important intermediate targets for commissural axons in the spinal cord and brain, including the corpus callosum. The role of midline glial populations and pioneering axons in the formation of the corpus callosum are discussed. Finally the differential guidance of the ipsilaterally projecting perforating pathway and the contralaterally projecting corpus callosum is addressed. Development of the corpus callosum involves the coordination of a number of different guidance mechanisms and the probable involvement of a large number of molecules.

  3. Blast overpressure induced axonal injury changes in rat brainstem and spinal cord

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    Srinivasu Kallakuri

    2015-01-01

    Full Text Available Introduction: Blast induced neurotrauma has been the signature wound in returning soldiers from the ongoing wars in Iraq and Afghanistan. Of importance is understanding the pathomechansim(s of blast overpressure (OP induced axonal injury. Although several recent animal models of blast injury indicate the neuronal and axonal injury in various brain regions, animal studies related to axonal injury in the white matter (WM tracts of cervical spinal cord are limited. Objective: The purpose of this study was to assess the extent of axonal injury in WM tracts of cervical spinal cord in male Sprague Dawley rats subjected to a single insult of blast OP. Materials and Methods: Sagittal brainstem sections and horizontal cervical spinal cord sections from blast and sham animals were stained by neurofilament light (NF-L chain and beta amyloid precursor protein immunocytochemistry and observed for axonal injury changes. Results: Observations from this preliminary study demonstrate axonal injury changes in the form of prominent swellings, retraction bulbs, and putative signs of membrane disruptions in the brainstem and cervical spinal cord WM tracts of rats subjected to blast OP. Conclusions: Prominent axonal injury changes following the blast OP exposure in brainstem and cervical spinal WM tracts underscores the need for careful evaluation of blast induced injury changes and associated symptoms. NF-L immunocytochemistry can be considered as an additional tool to assess the blast OP induced axonal injury.

  4. A developmental timing switch promotes axon outgrowth independent of known guidance receptors.

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    Katherine Olsson-Carter

    2010-08-01

    Full Text Available To form functional neuronal connections, axon outgrowth and guidance must be tightly regulated across space as well as time. While a number of genes and pathways have been shown to control spatial features of axon development, very little is known about the in vivo mechanisms that direct the timing of axon initiation and elongation. The Caenorhabditis elegans hermaphrodite specific motor neurons (HSNs extend a single axon ventrally and then anteriorly during the L4 larval stage. Here we show the lin-4 microRNA promotes HSN axon initiation after cell cycle withdrawal. Axons fail to form in lin-4 mutants, while they grow prematurely in lin-4-overexpressing animals. lin-4 is required to down-regulate two inhibitors of HSN differentiation--the transcriptional regulator LIN-14 and the "stemness" factor LIN-28--and it likely does so through a cell-autonomous mechanism. This developmental switch depends neither on the UNC-40/DCC and SAX-3/Robo receptors nor on the direction of axon growth, demonstrating that it acts independently of ventral guidance signals to control the timing of HSN axon elongation.

  5. Polarized targeting of L1-CAM regulates axonal and dendritic bundling in vitro.

    Science.gov (United States)

    Barry, Joshua; Gu, Yuanzheng; Gu, Chen

    2010-11-01

    Proper axonal and dendritic bundling is essential for the establishment of neuronal connections and the synchronization of synaptic inputs, respectively. Cell adhesion molecules of the L1-CAM (L1-cell adhesion molecule) family regulate axon guidance and fasciculation, neuron migration, dendrite morphology, and synaptic plasticity. It remains unclear how these molecules play so many different roles. Here we show that polarized axon-dendrite targeting of an avian L1-CAM protein, NgCAM (neuron-glia cell adhesion molecule), can regulate the switch of bundling of the two major compartments of rat hippocampal neurons. Using a new in-vitro model for studying neurite-neurite interactions, we found that expressed axonal NgCAM induced robust axonal bundling via the trans-homophilic interaction of immunoglobulin domains. Interestingly, dendritic bundling was induced by the dendritic targeting of NgCAM, caused by either deleting its fibronectin repeats or blocking activities of protein kinases. Consistent with the NgCAM results, expression of mouse L1-CAM also induced axonal bundling and blocking kinase activities disrupted its axonal targeting. Furthermore, the trans-homophilic interaction stabilized the bundle formation, probably through recruiting NgCAM proteins to contact sites and promoting guided axon outgrowth. Taken together, our results suggest that precise localization of L1-CAM is important for establishing proper cell-cell contacts in neural circuits.

  6. Integration of shallow gradients of Shh and Netrin-1 guides commissural axons.

    Science.gov (United States)

    Sloan, Tyler F W; Qasaimeh, Mohammad A; Juncker, David; Yam, Patricia T; Charron, Frédéric

    2015-03-01

    During nervous system development, gradients of Sonic Hedgehog (Shh) and Netrin-1 attract growth cones of commissural axons toward the floor plate of the embryonic spinal cord. Mice defective for either Shh or Netrin-1 signaling have commissural axon guidance defects, suggesting that both Shh and Netrin-1 are required for correct axon guidance. However, how Shh and Netrin-1 collaborate to guide axons is not known. We first quantified the steepness of the Shh gradient in the spinal cord and found that it is mostly very shallow. We then developed an in vitro microfluidic guidance assay to simulate these shallow gradients. We found that axons of dissociated commissural neurons respond to steep but not shallow gradients of Shh or Netrin-1. However, when we presented axons with combined Shh and Netrin-1 gradients, they had heightened sensitivity to the guidance cues, turning in response to shallower gradients that were unable to guide axons when only one cue was present. Furthermore, these shallow gradients polarized growth cone Src-family kinase (SFK) activity only when Shh and Netrin-1 were combined, indicating that SFKs can integrate the two guidance cues. Together, our results indicate that Shh and Netrin-1 synergize to enable growth cones to sense shallow gradients in regions of the spinal cord where the steepness of a single guidance cue is insufficient to guide axons, and we identify a novel type of synergy that occurs when the steepness (and not the concentration) of a guidance cue is limiting.

  7. In vivo Imaging of Mitochondrial Transport in Single-Axon Regeneration of Zebrafish Mauthner Cells

    Science.gov (United States)

    Xu, Yang; Chen, Min; Hu, Bingbing; Huang, Rongchen; Hu, Bing

    2017-01-01

    Mitochondrial transport is essential for neuronal function, but the evidence of connections between mitochondrial transport and axon regeneration in the central nervous system (CNS) of living vertebrates remains limited. Here, we developed a novel model to explore mitochondrial transport in a single Mauthner axon (M axon) of zebrafish with non-invasive in vivo imaging. To confirm the feasibility of using this model, we treated labeled zebrafish with nocodazole and demonstrated that it could disrupt mitochondrial transport. We also used two-photon laser axotomy to precisely axotomize M axons and simultaneously recorded their regeneration and the process of mitochondrial transport in living zebrafish larvae. The findings showed that the injured axons with stronger regenerative capability maintain greater mitochondrial motility. Furthermore, to stimulate axon regeneration, treatment with dibutyryl cyclic adenosine monophosphate (db-cAMP) could also augment mitochondrial motility. Taken together, our results provide new evidence that mitochondrial motility is positively correlated with axon regeneration in the living vertebrate CNS. This promising model will be useful for further studies on the interaction between axon regeneration and mitochondrial dynamics, using various genetic and pharmacological techniques. PMID:28174522

  8. Quantifying visual pathway axonal and myelin loss in multiple sclerosis and neuromyelitis optica

    Directory of Open Access Journals (Sweden)

    Praveena Manogaran

    2016-01-01

    Conclusions: The relationship between reductions in OCT measures of neuro-axonal health in the anterior visual pathway and MRI-based measures of myelin health in the posterior visual pathway suggests that these measures may be linked through bidirectional axonal degeneration.

  9. Inhibition of kinesin-5 improves regeneration of injured axons by a novel microtubule-based mechanism

    Directory of Open Access Journals (Sweden)

    Peter W Baas

    2015-01-01

    Full Text Available Microtubules have been identified as a powerful target for augmenting regeneration of injured adult axons in the central nervous system. Drugs that stabilize microtubules have shown some promise, but there are concerns that abnormally stabilizing microtubules may have only limited benefits for regeneration, while at the same time may be detrimental to the normal work that microtubules perform for the axon. Kinesin-5 (also called kif11 or Eg5, a molecular motor protein best known for its crucial role in mitosis, acts as a brake on microtubule movements by other motor proteins in the axon. Drugs that inhibit kinesin-5, originally developed to treat cancer, result in greater mobility of microtubules in the axon and an overall shift in the forces on the microtubule array. As a result, the axon grows faster, retracts less, and more readily enters environments that are inhibitory to axonal regeneration. Thus, drugs that inhibit kinesin-5 offer a novel microtubule-based means to boost axonal regeneration without the concerns that accompany abnormal stabilization of the microtubule array. Even so, inhibiting kinesin-5 is not without its own caveats, such as potential problems with navigation of the regenerating axon to its target, as well as morphological effects on dendrites that could affect learning and memory if the drugs reach the brain.

  10. The course of axons through the retina and optic nerve head.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1979-06-01

    By identifying degenerating axons in tissue specimens from 22 primate eyes, it was possible to demonstrate the normal course of axon fibers. Nerve fiber bundles from a group of retinal ganglion cells travel together with little tendency to disperse laterally. In addition, axons are stratified such that processes from more central ganglion cells are successfully added to the inner strata of the retinal nerve fiber layer. Within and behind the lamina cribrosa, areas of degeneration following retinal photocoagulation were well circumscribed and confined to a group of adjacent axon bundles. This degree of retinotopic organization of axons within the nerve head and retinal fiber layer is believed to be consistent with the premise that isolated lesions within the lamina cribrosa could cause well-organized paracentral scotomas such as those characteristic of early glaucoma.

  11. BmRobo2/3 is required for axon guidance in the silkworm Bombyx mori.

    Science.gov (United States)

    Li, Xiao-Tong; Yu, Qi; Zhou, Qi-Sheng; Zhao, Xiao; Liu, Zhao-Yang; Cui, Wei-Zheng; Liu, Qing-Xin

    2016-02-15

    Axon guidance is critical for proper wiring of the nervous system. During the neural development, the axon guidance molecules play a key role and direct axons to choose the correct way to reach the target. Robo, as the receptor of axon guidance molecule Slit, is evolutionarily conserved from planarians to humans. However, the function of Robo in the silkworm, Bombyx mori, remained unknown. In this study, we cloned robo2/3 from B. mori (Bmrobo2/3), a homologue of robo2/3 in Tribolium castaneum. Moreover, BmRobo2/3 was localized in the neuropil, and RNAi-mediated knockdown of Bmrobo2/3 resulted in the longitudinal connectives forming closer to the midline. These data demonstrate that BmRobo2/3 is required for axon guidance in the silkworm.

  12. Electromagnetic induction between axons and their schwann cell myelin-protein sheaths.

    Science.gov (United States)

    Goodman, G; Bercovich, D

    2013-12-01

    Two concepts have long dominated vertebrate nerve electrophysiology: (a) Schwann cell-formed myelin sheaths separated by minute non-myelinated nodal gaps and spiraling around axons of peripheral motor nerves reduce current leakage during propagation of trains of axon action potentials; (b) "jumping" by action potentials between successive nodes greatly increases signal conduction velocity. Long-held and more recent assumptions and issues underlying those concepts have been obscured by research emphasis on axon-sheath biochemical symbiosis and nerve regeneration. We hypothesize: mutual electromagnetic induction in the axon-glial sheath association, is fundamental in signal conduction in peripheral and central myelinated axons, explains the g-ratio and is relevant to animal navigation.

  13. The autophagy gene Wdr45/Wipi4 regulates learning and memory function and axonal homeostasis.

    Science.gov (United States)

    Zhao, Yan G; Sun, Le; Miao, Guangyan; Ji, Cuicui; Zhao, Hongyu; Sun, Huayu; Miao, Lin; Yoshii, Saori R; Mizushima, Noboru; Wang, Xiaoqun; Zhang, Hong

    2015-01-01

    WDR45/WIPI4, encoding a WD40 repeat-containing PtdIns(3)P binding protein, is essential for the basal autophagy pathway. Mutations in WDR45 cause the neurodegenerative disease β-propeller protein-associated neurodegeneration (BPAN), a subtype of NBIA. We generated CNS-specific Wdr45 knockout mice, which exhibit poor motor coordination, greatly impaired learning and memory, and extensive axon swelling with numerous axon spheroids. Autophagic flux is defective and SQSTM1 (sequestosome-1)/p62 and ubiquitin-positive protein aggregates accumulate in neurons and swollen axons. Nes-Wdr45(fl/Y) mice recapitulate some hallmarks of BPAN, including cognitive impairment and defective axonal homeostasis, providing a model for revealing the disease pathogenesis of BPAN and also for investigating the possible role of autophagy in axon maintenance.

  14. Exposure to 1-bromopropane causes degeneration of noradrenergic axons in the rat brain.

    Science.gov (United States)

    Mohideen, Sahabudeen Sheik; Ichihara, Gaku; Ichihara, Sahoko; Nakamura, Shoji

    2011-07-11

    1-Bromopropane (1-BP) has been used as an alternative to ozone-depleting solvents. Previous studies showed that 1-BP is neurotoxic in animals and humans. In humans, exposure to 1-BP caused various neurological and neurobehavioral symptoms or signs including depressive or irritated mood. However, the neurobiological changes underlying the depressive symptoms induced by 1-BP remain to be determined. The depressive symptoms are thought to be associated with degeneration of axons containing noradrenaline and serotonin. Based on this hypothesis, the present study examined the effects of repeated exposure to 1-BP on serotonergic and noradrenergic axons. Exposure to 1-BP induced dose-dependent decreases in the density of noradrenergic axons in the rat prefrontal cortex, but no apparent change in the density of serotonergic axons. The results suggest that depressive symptoms in workers exposed to 1-BP are due, at least in part, to the degeneration of noradrenergic axons in the brain.

  15. PACSIN1, a Tau-interacting protein, regulates axonal elongation and branching by facilitating microtubule instability.

    Science.gov (United States)

    Liu, Yingying; Lv, Kaosheng; Li, Zenglong; Yu, Albert C H; Chen, Jianguo; Teng, Junlin

    2012-11-16

    Tau is a major member of the neuronal microtubule-associated proteins. It promotes tubulin assembly and stabilizes axonal microtubules. Previous studies have demonstrated that Tau forms cross-bridges between microtubules, with some particles located on cross-bridges, suggesting that some proteins interact with Tau and might be involved in regulating Tau-related microtubule dynamics. This study reports that PACSIN1 interacts with Tau in axon. PACSIN1 blockade results in impaired axonal elongation and a higher number of primary axonal branches in mouse dorsal root ganglia neurons, which is induced by increasing the binding ability of Tau to microtubules. In PACSIN1-blocked dorsal root ganglia neurons, a greater amount of Tau is inclined to accumulate in the central domain of growth cones, and it promotes the stability of the microtubule network. Taken together, these results suggest that PACSIN1 is an important Tau binding partner in regulating microtubule dynamics and forming axonal plasticity.

  16. Transfer of vesicles from Schwann cell to axon: a novel mechanism of communication in the peripheral nervous system

    Directory of Open Access Journals (Sweden)

    María Alejandra eLopez-Verrilli

    2012-06-01

    Full Text Available Schwann cells (SCs are the glial component of the peripheral nervous system, with essential roles during development and maintenance of axons, as well as during regenerative processes after nerve injury. SCs increase conduction velocities by myelinating axons, regulate synaptic activity at presynaptic nerve terminals and are a source of trophic factors to neurons. Thus, development and maintenance of peripheral nerves are crucially dependent on local signalling between SCs and axons. In addition to the classic mechanisms of intercellular signalling, the possibility of communication through secreted vesicles has been poorly explored to date. Interesting recent findings suggest the occurrence of lateral transfer mediated by vesicles from glial cells to axons that could have important roles in axonal growth and axonal regeneration. Here, we review the role of vesicular transfer from SCs to axons and propose the benefits of this means in supporting neuronal and axonal maintenance and regeneration after nerve damage.

  17. Axonal regeneration through the fibrous scar in lesioned goldfish spinal cord.

    Science.gov (United States)

    Takeda, A; Atobe, Y; Kadota, T; Goris, R C; Funakoshi, K

    2015-01-22

    Spontaneous nerve regeneration beyond the scar frequently occurs in fish after spinal cord lesions, in contrast to mammals. Here we examined the spatiotemporal relationship between the fibrous scar and axonal regeneration in the goldfish. Within 1 week after hemisection of the spinal cord, the open wound was closed by a fibrous scar that was demarcated from the surrounding nervous tissue by the glia limitans, which was immunoreactive for laminin. Within 1 week after hemisection, regenerating axons entered the fibrous scar, and were surrounded by laminin-coated tubular structures continuous with the glia limitans. Regenerating axons that initially entered the fibrous scar were usually accompanied by glial processes. Within 2-3 weeks after hemisection, the tubular structures became enlarged, and the regenerating axons increased in number, fasciculating in the tubules. Glial processes immunoreactive for glial fibrillary acid protein and 5-hydroxytryptamine neurons then entered the tubular structures to associate with the regenerating axons. The tubular structures developed further, creating tunnels that penetrated the fibrous scar, through which the regenerating axons passed. At 6-12 weeks after hemisection, the fibrous scar was smaller and the enlarged tunnels contained many glial processes and several axons. The findings of present study demonstrated that, following spinal lesions in goldfish, regenerating axons enter and pass the scar tissue. The regenerating axons first enter the fibrous scar with glial elements and then grow through laminin-coated tubular structures within the fibrous scar. Invasion by glial processes and neuronal elements into the tubular structures reduces the fibrous scar area and allows for more regenerating axons to pass beyond the fibrous scar.

  18. Sonic Hedgehog Guides Axons via Zipcode Binding Protein 1-Mediated Local Translation.

    Science.gov (United States)

    Lepelletier, Léa; Langlois, Sébastien D; Kent, Christopher B; Welshhans, Kristy; Morin, Steves; Bassell, Gary J; Yam, Patricia T; Charron, Frédéric

    2017-02-15

    Sonic hedgehog (Shh) attracts spinal cord commissural axons toward the floorplate. How Shh elicits changes in the growth cone cytoskeleton that drive growth cone turning is unknown. We find that the turning of rat commissural axons up a Shh gradient requires protein synthesis. In particular, Shh stimulation increases β-actin protein at the growth cone even when the cell bodies have been removed. Therefore, Shh induces the local translation of β-actin at the growth cone. We hypothesized that this requires zipcode binding protein 1 (ZBP1), an mRNA-binding protein that transports β-actin mRNA and releases it for local translation upon phosphorylation. We found that Shh stimulation increases phospho-ZBP1 levels in the growth cone. Disruption of ZBP1 phosphorylation in vitro abolished the turning of commissural axons toward a Shh gradient. Disruption of ZBP1 function in vivo in mouse and chick resulted in commissural axon guidance errors. Therefore, ZBP1 is required for Shh to guide commissural axons. This identifies ZBP1 as a new mediator of noncanonical Shh signaling in axon guidance.SIGNIFICANCE STATEMENT Sonic hedgehog (Shh) guides axons via a noncanonical signaling pathway that is distinct from the canonical Hedgehog signaling pathway that specifies cell fate and morphogenesis. Axon guidance is driven by changes in the growth cone in response to gradients of guidance molecules. Little is known about the molecular mechanism of how Shh orchestrates changes in the growth cone cytoskeleton that are required for growth cone turning. Here, we show that the guidance of axons by Shh requires protein synthesis. Zipcode binding protein 1 (ZBP1) is an mRNA-binding protein that regulates the local translation of proteins, including actin, in the growth cone. We demonstrate that ZBP1 is required for Shh-mediated axon guidance, identifying a new member of the noncanonical Shh signaling pathway.

  19. Interleukin (IL)-8 immunoreactivity of injured axons and surrounding oligodendrocytes in traumatic head injury.

    Science.gov (United States)

    Hayashi, Takahito; Ago, Kazutoshi; Nakamae, Takuma; Higo, Eri; Ogata, Mamoru

    2016-06-01

    Interleukin (IL)-8 has been suggested to be a positive regulator of myelination in the central nervous system, in addition to its principal role as a chemokine for neutrophils. Immunostaining for beta-amyloid precursor protein (AβPP) is an effective tool for detecting traumatic axonal injury, although AβPP immunoreactivity can also indicate axonal injury due to hypoxic causes. In this study, we examined IL-8 and AβPP immunoreactivity in sections of corpus callosum obtained from deceased patients with blunt head injury and from equivalent control tissue. AβPP immunoreactivity was detected in injured axons, such as axonal bulbs and varicose axons, in 24 of 44 head injury cases. These AβPP immunoreactive cases had survived for more than 3h. The AβPP immunostaining pattern can be classified into two types: traumatic (Pattern 1) and non-traumatic (Pattern 2) axonal injuries, which we described previously [Hayashi et al. Int. J. Legal Med. 129 (2015) 1085-1090]. Three of 44 control cases also showed AβPP immunoreactive injured axons as Pattern 2. In contrast, IL-8 immunoreactivity was detected in 7 AβPP immunoreactive and in 2 non-AβPP immunoreactive head injury cases, but was not detected in any of the 44 control cases, including the 3 AβPP immunoreactive control cases. The IL-8 immunoreactive cases had survived from 3 to 24 days, whereas those cases who survived less than 3 days (n=29) and who survived 90 days (n=1) were not IL-8 immunoreactive. Moreover, IL-8 was detected as Pattern 1 axons only. In addition, double immunofluorescence analysis showed that IL-8 is expressed by oligodendrocytes surrounding injured axons. In conclusion, our results suggest that immunohistochemical detection of IL-8 may be useful as a complementary diagnostic marker of traumatic axonal injury.

  20. Shh signaling guides spatial pathfinding of raphespinal tract axons by multidirectional repulsion

    Institute of Scientific and Technical Information of China (English)

    Lijuan Song; Yuehui Liu; YangYu; Xin Duan; Shening Qi; Yaobo Liu

    2012-01-01

    Relatively little is known about the molecular mechanisms underlying spatial pathfinding in the descending serotonergic raphespinal tract (RST) in the developing spinal cord,one of the most important nerve pathways for pain,sensory and motor functions.We provide evidence that ventral floor plate-secreted Sonic hedgehog (Shh) is responsible for the establishment of decreasing gradients in both the anterior-to-posterior (A-P) and the medialto-lateral (M-L) directions in the ventral spinal cord during serotonergic RST axon projection.Downstream components of the Shh pathway,Patched 1 (Ptch1) and Smoothened (Smo),were expressed in the serotonergic caudal raphe nuclei and enriched in the descending serotonergic RST axons.Diffusible Shh repulsion of serotonergic RST axons was shown to be mediated by Shh-Ptch1 interactions and derepression of Smo.Using a co-culture assay,we showed that A-P graded repulsion mediated by Shh signaling pushed the serotonergic axons caudally through the ventral spinal cord and M-L graded repulsion mediated by Shh signaling simultaneously restricted the serotonergic axons to the ventral and ventral-lateral funiculus.Prominent pathfinding errors of serotonergic RST axons were observed in various Shh,Ptch1 and Smo mutants.We conclude that Shh signaling-mediated multidirectional repulsion is required to push descending serotonergic RST axons in the A-P direction,and to restrict these axons to the ventral and ventral-lateral funiculus in the M-L direction.This is the first demonstration that Shh signalingmediated muitidirectional repulsion of serotonergic RST axons maintains spatial axon pathfinding in the developing spinal cord.

  1. Shh signaling guides spatial pathfinding of raphespinal tract axons by multidirectional repulsion.

    Science.gov (United States)

    Song, Lijuan; Liu, Yuehui; Yu, Yang; Duan, Xin; Qi, Shening; Liu, Yaobo

    2012-04-01

    Relatively little is known about the molecular mechanisms underlying spatial pathfinding in the descending serotonergic raphespinal tract (RST) in the developing spinal cord, one of the most important nerve pathways for pain, sensory and motor functions. We provide evidence that ventral floor plate-secreted Sonic hedgehog (Shh) is responsible for the establishment of decreasing gradients in both the anterior-to-posterior (A-P) and the medial-to-lateral (M-L) directions in the ventral spinal cord during serotonergic RST axon projection. Downstream components of the Shh pathway, Patched 1 (Ptch1) and Smoothened (Smo), were expressed in the serotonergic caudal raphe nuclei and enriched in the descending serotonergic RST axons. Diffusible Shh repulsion of serotonergic RST axons was shown to be mediated by Shh-Ptch1 interactions and derepression of Smo. Using a co-culture assay, we showed that A-P graded repulsion mediated by Shh signaling pushed the serotonergic axons caudally through the ventral spinal cord and M-L graded repulsion mediated by Shh signaling simultaneously restricted the serotonergic axons to the ventral and ventral-lateral funiculus. Prominent pathfinding errors of serotonergic RST axons were observed in various Shh, Ptch1 and Smo mutants. We conclude that Shh signaling-mediated multidirectional repulsion is required to push descending serotonergic RST axons in the A-P direction, and to restrict these axons to the ventral and ventral-lateral funiculus in the M-L direction. This is the first demonstration that Shh signaling-mediated multidirectional repulsion of serotonergic RST axons maintains spatial axon pathfinding in the developing spinal cord.

  2. The role of microtubule-associated protein 1B in axonal growth and neuronal migration in the central nervous system

    Institute of Scientific and Technical Information of China (English)

    Maoguang Yang; Xiaoyu Yang; Minfei Wu; Peng Xia; Chunxin Wang; Peng Yan; Qi Gao; Jian Liu; Haitao Wang; Xingwei Duan

    2012-01-01

    In this review, we discuss the role of microtubule-associated protein 1B (MAP1B) and its phosphorylation in axonal development and regeneration in the central nervous system. MAP1B exhibits similar functions during axonal development and regeneration. MAP1B and phosphorylated MAP1B in neurons and axons maintain a dynamic balance between cytoskeletal components, and regulate the stability and interaction of microtubules and actin to promote axonal growth, neural connectivity and regeneration in the central nervous system.

  3. A macroscopic model of traffic jams in axons.

    Science.gov (United States)

    Kuznetsov, A V; Avramenko, A A

    2009-04-01

    The purpose of this paper is to develop a minimal macroscopic model capable of explaining the formation of traffic jams in fast axonal transport. The model accounts for the decrease of the number density of positively (and negatively) oriented microtubules near the location of the traffic jam due to formation of microtubule swirls; the model also accounts for the reduction of the effective velocity of organelle transport in the traffic jam region due to organelles falling off microtubule tracks more often in the swirl region. The model is based on molecular-motor-assisted transport equations and the hydrodynamic model of traffic jams in highway traffic. Parametric analyses of the model's predictions for various values of viscosity of the traffic flow, variance of the velocity distribution, diffusivity of microtubule-bound and free organelles, rate constants for binding to and detachment from microtubules, relaxation time, and average motor velocities of the retrograde and anterograde transport, are carried out.

  4. Video Object Tracking in Neural Axons with Fluorescence Microscopy Images

    Directory of Open Access Journals (Sweden)

    Liang Yuan

    2014-01-01

    tracking. In this paper, we describe two automated tracking methods for analyzing neurofilament movement based on two different techniques: constrained particle filtering and tracking-by-detection. First, we introduce the constrained particle filtering approach. In this approach, the orientation and position of a particle are constrained by the axon’s shape such that fewer particles are necessary for tracking neurofilament movement than object tracking techniques based on generic particle filtering. Secondly, a tracking-by-detection approach to neurofilament tracking is presented. For this approach, the axon is decomposed into blocks, and the blocks encompassing the moving neurofilaments are detected by graph labeling using Markov random field. Finally, we compare two tracking methods by performing tracking experiments on real time-lapse image sequences of neurofilament movement, and the experimental results show that both methods demonstrate good performance in comparison with the existing approaches, and the tracking accuracy of the tracing-by-detection approach is slightly better between the two.

  5. Neural signal registration and analysis of axons grown in microchannels

    Science.gov (United States)

    Pigareva, Y.; Malishev, E.; Gladkov, A.; Kolpakov, V.; Bukatin, A.; Mukhina, I.; Kazantsev, V.; Pimashkin, A.

    2016-08-01

    Registration of neuronal bioelectrical signals remains one of the main physical tools to study fundamental mechanisms of signal processing in the brain. Neurons generate spiking patterns which propagate through complex map of neural network connectivity. Extracellular recording of isolated axons grown in microchannels provides amplification of the signal for detailed study of spike propagation. In this study we used neuronal hippocampal cultures grown in microfluidic devices combined with microelectrode arrays to investigate a changes of electrical activity during neural network development. We found that after 5 days in vitro after culture plating the spiking activity appears first in microchannels and on the next 2-3 days appears on the electrodes of overall neural network. We conclude that such approach provides a convenient method to study neural signal processing and functional structure development on a single cell and network level of the neuronal culture.

  6. Axonal transport interruption and anatomy at the lamina cribrosa.

    Science.gov (United States)

    Radius, R L; Bade, B

    1982-10-01

    Pressure-induced, focal axonal transport abnormalities were studied in 14 cat eyes by the examination of serial step-section tissue radioautogram. Although the patterns of the transport interruption at the lamina cribrosa varied from eye to eye, the temporal sectors of the nerve head were most often involved by this abnormality. The anatomy at the lamina cribrosa was studied in adjacent (6 micrometers) cross-sectional specimens. The thickness of the extra-bundle trabeculae and the nerve fiber bundle dimensions including the cross-sectional area and the number and the shape (the ratio of the major and the minor axis diameters) of the laminar pores were measured by computer-assisted perimeter analysis. There was no correlation between the location of the transport interruption and any of these anatomic measurements.

  7. Diagnosis and treatment of diffuse axonal injury in 169 patients

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-yong; YANG Zhen-jiu; FENG Cheng-xuan; LI Hong-wei; LI Wei-ping; ZHANG Jun; ZHANG Hong

    2005-01-01

    Objective: To evaluate current diagnosis and therapeutic effect and outcome of diffuse axonal injury (DAI) in 169 patients.Methods: The data of 169 DAI patients treated in the Second, Sixth, Eighth and Ninth Hospitals of Shenzhen and Shekou Hospital from January 2001 to January 2005 were collected. The imaging features, classification, GCS (Glasgow coma scale), treatment and outcome of the 169patients were retrospectively analyzed.Results: The simpler the imaging features, the closer the focus of DAI to the periphery of hemisphere and the higher the GCS score, the better the prognoses of DAI patients will be.Conclusions: The prognoses of DAI patients are closely related to the imaging features and classification,GCS and clinical treatment.

  8. Mechanisms of hyperpolarization in regenerated mature motor axons in cat

    DEFF Research Database (Denmark)

    Moldovan, Mihai; Krarup, Christian

    2004-01-01

    We found persistent abnormalities in the recovery of membrane excitability in long-term regenerated motor nerve fibres in the cat as indicated in the companion paper. These abnormalities could partly be explained by membrane hyperpolarization. To further investigate this possibility, we compared...... the changes in excitability in control nerves and long-term regenerated cat nerves (3-5 years after tibial nerve crush) during manoeuvres known to alter axonal membrane Na(+)-K(+) pump function: polarization, cooling to 20 degrees C, reperfusion after 10 min ischaemia, and up to 60 s of repetitive stimulation...... at 200 Hz. The abnormalities in excitability of regenerated nerves were reduced by depolarization and cooling and increased by hyperpolarization and during postischaemia. Moreover, the time course of recovery of excitability from repetitive stimulation and ischaemia was prolonged in regenerated nerves...

  9. Multimodal transition and stochastic antiresonance in squid giant axons

    CERN Document Server

    Borkowski, L S

    2010-01-01

    The experimental data of N. Takahashi, Y. Hanyu, T. Musha, R. Kubo, and G. Matsumoto, Physica D \\textbf{43}, 318 (1990), on the response of squid giant axons stimulated by periodic sequence of short current pulses is interpreted within the Hodgkin-Huxley model. The minimum of the firing rate as a function of the stimulus amplitude $I_0$ in the high-frequency regime is due to the multimodal transition. Below this singular point only odd multiples of the driving period remain and the system is highly sensitive to noise. The coefficient of variation has a maximum and the firing rate has a minimum as a function of the noise intensity which is an indication of the stochastic coherence antiresonance. The model calculations reproduce the frequency of occurrence of the most common modes in the vicinity of the transition. A linear relation of output frequency vs. $I_0$ for above the transition is also confirmed.

  10. Dynamic Changes in Local Protein Synthetic Machinery in Regenerating Central Nervous System Axons after Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Rahul Sachdeva

    2016-01-01

    Full Text Available Intra-axonal localization of mRNAs and protein synthesis machinery (PSM endows neurons with the capacity to generate proteins locally, allowing precise spatiotemporal regulation of the axonal response to extracellular stimuli. A number of studies suggest that this local translation is a promising target to enhance the regenerative capacity of damaged axons. Using a model of central nervous system (CNS axons regenerating into intraspinal peripheral nerve grafts (PNGs we established that adult regenerating CNS axons contain several different mRNAs and protein synthetic machinery (PSM components in vivo. After lower thoracic level spinal cord transection, ascending sensory axons regenerate into intraspinal PNGs but axon growth is stalled when they reach the distal end of the PNG (3 versus 7 weeks after grafting, resp.. By immunofluorescence with optical sectioning of axons by confocal microscopy, the total and phosphorylated forms of PSMs are significantly lower in stalled compared with actively regenerating axons. Reinjury of these stalled axons increased axonal localization of the PSM proteins, indicative of possible priming for a subcellular response to axotomy. These results suggest that axons downregulate protein synthetic capacity as they cease growing, yet they retain the ability to upregulate PSM after a second injury.

  11. Multichannel activity propagation across an engineered axon network

    Science.gov (United States)

    Chen, H. Isaac; Wolf, John A.; Smith, Douglas H.

    2017-04-01

    Objective. Although substantial progress has been made in mapping the connections of the brain, less is known about how this organization translates into brain function. In particular, the massive interconnectivity of the brain has made it difficult to specifically examine data transmission between two nodes of the connectome, a central component of the ‘neural code.’ Here, we investigated the propagation of multiple streams of asynchronous neuronal activity across an isolated in vitro ‘connectome unit.’ Approach. We used the novel technique of axon stretch growth to create a model of a long-range cortico-cortical network, a modular system consisting of paired nodes of cortical neurons connected by axon tracts. Using optical stimulation and multi-electrode array recording techniques, we explored how input patterns are represented by cortical networks, how these representations shift as they are transmitted between cortical nodes and perturbed by external conditions, and how well the downstream node distinguishes different patterns. Main results. Stimulus representations included direct, synaptic, and multiplexed responses that grew in complexity as the distance between the stimulation source and recorded neuron increased. These representations collapsed into patterns with lower information content at higher stimulation frequencies. With internodal activity propagation, a hierarchy of network pathways, including latent circuits, was revealed using glutamatergic blockade. As stimulus channels were added, divergent, non-linear effects were observed in local versus distant network layers. Pairwise difference analysis of neuronal responses suggested that neuronal ensembles generally outperformed individual cells in discriminating input patterns. Significance. Our data illuminate the complexity of spiking activity propagation in cortical networks in vitro, which is characterized by the transformation of an input into myriad outputs over several network layers

  12. Electrocardiografo por computadora

    OpenAIRE

    Tinoco Hernandez, Rosanna; Paredes Bejarano, Margarita; Romero Chaglia, Norman; Yapur Auad, Miguel Eduardo

    2009-01-01

    El presente trabajo trata sobrees el diseño y la implementación de un graficador de señales cardiacas por computadora, para lo cual diseñamos un circuito electrónico capaz de recibir la senal analógica proveniente de la actividad electrica del corazón , amplificarla, y luego convertirla en una señal digital para ser procesada por software y finalmente ser graficada, siendo posible así observar la señal cardiaca en el monitor de un computador como un tren de pulsos. Cabe destacar que par...

  13. Axon extension in the fast and slow lanes: substratum-dependent engagement of myosin II functions.

    Science.gov (United States)

    Ketschek, Andrea R; Jones, Steven L; Gallo, Gianluca

    2007-09-01

    Axon extension involves the coordinated regulation of the neuronal cytoskeleton. Actin filaments drive protrusion of filopodia and lamellipodia while microtubules invade the growth cone, thereby providing structural support for the nascent axon. Furthermore, in order for axons to extend the growth cone must attach to the substratum. Previous work indicates that myosin II activity inhibits the advance of microtubules into the periphery of growth cones, and myosin II has also been implicated in mediating integrin-dependent cell attachment. However, it is not clear how the functions of myosin II in regulating substratum attachment and microtubule advance are integrated during axon extension. We report that inhibition of myosin II function decreases the rate of axon extension on laminin, but surprisingly promotes extension rate on polylysine. The differential effects of myosin II inhibition on axon extension rate are attributable to myosin II having the primary function of mediating substratum attachment on laminin, but not on polylysine. Conversely, on polylysine the primary function of myosin II is to inhibit microtubule advance into growth cones. Thus, the substratum determines the role of myosin II in axon extension by controlling the functions of myosin II that contribute to extension.

  14. Modeling the mechanics of axonal fiber tracts using the embedded finite element method.

    Science.gov (United States)

    Garimella, Harsha T; Kraft, Reuben H

    2016-08-08

    A subject-specific human head finite element model with embedded axonal fiber tractography obtained from diffusion tensor imaging was developed. The axonal fiber tractography finite element model was coupled with the volumetric elements in the head model using the embedded element method. This technique enables the calculation of axonal strains and real-time tracking of the mechanical response of the axonal fiber tracts. The coupled model was then verified using pressure and relative displacement-based (between skull and brain) experimental studies and was employed to analyze a head impact, demonstrating the applicability of this method in studying axonal injury. Following this, a comparison study of different injury criteria was performed. This model was used to determine the influence of impact direction on the extent of the axonal injury. The results suggested that the lateral impact loading is more dangerous compared to loading in the sagittal plane, a finding in agreement with previous studies. Through this analysis, we demonstrated the viability of the embedded element method as an alternative numerical approach for studying axonal injury in patient-specific human head models.

  15. Calpain-mediated cleavage of collapsin response mediator protein-2 drives acute axonal degeneration

    Science.gov (United States)

    Zhang, Jian-Nan; Michel, Uwe; Lenz, Christof; Friedel, Caroline C.; Köster, Sarah; d’Hedouville, Zara; Tönges, Lars; Urlaub, Henning; Bähr, Mathias; Lingor, Paul; Koch, Jan C.

    2016-01-01

    Axonal degeneration is a key initiating event in many neurological diseases. Focal lesions to axons result in a rapid disintegration of the perilesional axon by acute axonal degeneration (AAD) within several hours. However, the underlying molecular mechanisms of AAD are only incompletely understood. Here, we studied AAD in vivo through live-imaging of the rat optic nerve and in vitro in primary rat cortical neurons in microfluidic chambers. We found that calpain is activated early during AAD of the optic nerve and that calpain inhibition completely inhibits axonal fragmentation on the proximal side of the crush while it attenuates AAD on the distal side. A screening of calpain targets revealed that collapsin response mediator protein-2 (CRMP2) is a main downstream target of calpain activation in AAD. CRMP2-overexpression delayed bulb formation and rescued impairment of axonal mitochondrial transport after axotomy in vitro. In vivo, CRMP2-overexpression effectively protected the proximal axon from fragmentation within 6 hours after crush. Finally, a proteomic analysis of the optic nerve was performed at 6 hours after crush, which identified further proteins regulated during AAD, including several interactors of CRMP2. These findings reveal CRMP2 as an important mediator of AAD and define it as a putative therapeutic target. PMID:27845394

  16. Gene expression of axon growth promoting factors in the deer antler.

    Directory of Open Access Journals (Sweden)

    Wolfgang Pita-Thomas

    Full Text Available The annual regeneration cycle of deer (Cervidae, Artiodactyla antlers represents a unique model of epimorphic regeneration and rapid growth in adult mammals. Regenerating antlers are innervated by trigeminal sensory axons growing through the velvet, the modified form of skin that envelopes the antler, at elongation velocities that reach one centimetre per day in the common deer (Cervus elaphus. Several axon growth promoters like NT-3, NGF or IGF-1 have been described in the antler. To increase the knowledge on the axon growth environment, we have combined different gene-expression techniques to identify and characterize the expression of promoting molecules not previously described in the antler velvet. Cross-species microarray analyses of deer samples on human arrays allowed us to build up a list of 90 extracellular or membrane molecules involved in axon growth that were potentially being expressed in the antler. Fifteen of these genes were analysed using PCR and sequencing techniques to confirm their expression in the velvet and to compare it with the expression in other antler and skin samples. Expression of 8 axon growth promoters was confirmed in the velvet, 5 of them not previously described in the antler. In conclusion, our work shows that antler velvet provides growing axons with a variety of promoters of axon growth, sharing many of them with deer's normal and pedicle skin.

  17. Effect of fetal spinal cord graft with different methods on axonal pathology after spinal cord contusion

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To investigate the effect of fetal spinal cord (FSC) graft with different methods on axonal pathology and neurological function recovery after spinal cord injury (SCI).   Methods: Forty Wistar rats were divided into 4 groups. In Group A, the spinal cord was injured and hemisected. In Group B, fetal spinal cord (FSC) was transferred into the injured site. In Group C, after having done as Group B, the upper and lower spinal nerve roots were anastomosed. And in Group D, after having done as Group B, the pedicled omentum was transferred into the hemisection cavity. At 6 weeks after operation, light and electronic microscopes were used to examine the axonal pathology. The neurological function was assessed with inclined plane tests in the open field. The number of axons was quantitated by a computer image analysis system.   Results: A greater loss of axons was observed in Group A than that of other groups at 6 weeks. The sequence of the reduced rate of the axons was as following, Group A>Group B>Group C>Group D (P<0.05). The remaining axons were paralleled with the significant improvement in neurological function recovery of the rats.   Conclusions: It indicates that FSC and pedicled omentum grafts after SCI can protect the axons and promote the neurological function recovery of the rats.

  18. The use of proteomic analysis to study trafficking defects in axons.

    Science.gov (United States)

    Fu, Xiaoqin; Brown, Kristy J; Rayavarapu, Sree; Nagaraju, Kanneboyina; Liu, Judy S

    2016-01-01

    Mutations in microtubule subunits and microtubule-associated proteins are the causes of many neurological disorders. These human conditions are usually associated with axonal tract defects or degeneration. The molecular mechanisms of these axonal dysfunction are still largely unknown. Conventional methods may not yield a complete analysis of downstream molecules related to axonal dysfunctions. Therefore, we devised a simple unbiased method to screen molecular motors and axonal molecules, which might be involved in axonal defects. We performed our analysis in the mouse with a targeted deletion in the doublecortin (Dcx) gene. Dcx is a microtubule-associated protein with direct effects on microtubule motors. Furthermore, the knockout of Dcx and its functionally redundant structurally similar paralog, doublecortin-like kinase 1 (Dclk1), in mouse results in thinner or absent axon tracts, including the corpus callosum and anterior commissures. We compared protein profiles of corpus callosum from Dcx knockout and wild-type mouse of P0-P2 using mass spectrometry. This strategy allowed us to identify novel candidates downstream of Dcx involved in axon transport.

  19. Discoidin domain receptors guide axons along longitudinal tracts in C. elegans.

    Science.gov (United States)

    Unsoeld, Thomas; Park, Ja-On; Hutter, Harald

    2013-02-01

    Discoidin domain receptors are a family of receptor tyrosine kinases activated by collagens. Here we characterize the role of the two discoidin domain receptors, ddr-1 and ddr-2, of the nematode C. elegans during nervous system development. ddr-2 mutant animals exhibit axon guidance defects in major longitudinal tracts most prominently in the ventral nerve cord. ddr-1 mutants show no significant phenotype on their own but significantly enhance guidance defects of ddr-2 in double mutants. ddr-1 and ddr-2 GFP-reporter constructs are expressed in neurons with axons in all affected nerve tracts. DDR-1 and DDR-2 GFP fusion proteins localize to axons. DDR-2 is required cell-autonomously in the PVPR neuron for the guidance of the PVPR pioneer axon, which establishes the left ventral nerve cord tract and serves as substrate for later outgrowing follower axons. Our results provide the first insight on discoidin domain receptor function in invertebrates and establish a novel role for discoidin domain receptors in axon navigation and axon tract formation.

  20. Effects of axonal topology on the somatic modulation of synaptic outputs.

    Science.gov (United States)

    Sasaki, Takuya; Matsuki, Norio; Ikegaya, Yuji

    2012-02-22

    Depolarization of the neuronal soma augments synaptic output onto postsynaptic neurons via long-range, axonal cable properties. Here, we report that the range of this somatic influence is spatially restricted by not only axonal path length but also a branching-dependent decrease in axon diameter. Cell-attached recordings of action potentials (APs) from multiple axon branches of a rat hippocampal CA3 pyramidal cell revealed that an AP was broadened following a 20 mV depolarization of the soma and reverted to a normal width during propagation down the axon. The narrowing of the AP depended on the distance traveled by the AP and on the number of axon branch points through which the AP passed. These findings were confirmed by optical imaging of AP-induced calcium elevations in presynaptic boutons, suggesting that the somatic membrane potential modifies synaptic outputs near the soma but not long-projection outputs. Consistent with this prediction, whole-cell recordings from synaptically connected neurons revealed that depolarization of presynaptic CA3 pyramidal cells facilitated synaptic transmission to nearby CA3 pyramidal cells, but not to distant pyramidal cells in CA3 or CA1. Therefore, axonal geometry enables the differential modulation of synaptic output depending on target location.

  1. Characterizing Semaphorin-Mediated Effects on Sensory and Motor Axon Pathfinding and Connectivity During Embryonic Development.

    Science.gov (United States)

    Huettl, Rosa Eva; Huber, Andrea B

    2017-01-01

    How are precise connectivity to peripheral targets and corresponding sensory-motor networks established during developmental innervation of the vertebrate extremities? The formation of functional sensory-motor circuits requires highly appropriate temporal and spatial regulation of axon growth which is achieved through the combination of different molecular mechanisms such as communication between heterotypic fiber systems, axon-environment, or axon-glia interactions that ensure proper fasciculation and accurate pathfinding to distal targets. Family members of the class 3 semaphorins and their cognate receptors, the neuropilins, were shown to govern various events during wiring of central and peripheral circuits, with mice lacking Sema3-Npn signaling showing deficits in timing of growth, selective fasciculation, guidance fidelity, and coupling of sensory axon growth to motor axons at developmental time points. Given the accuracy with which these processes have to interact in a stepwise manner, deficiency of the smallest cog in the wheel may impact severely on the faithful establishment and functionality of peripheral circuitries, ultimately leading to behavioral impairments or even cause the death of the animal. Reliable quantitative analyses of sensory-motor fasciculation, extension, and guidance of axons to their cognate target muscles and the skin during development, but also assessment of physiological and behavioral consequences at adult age, are therefore a necessity to extend our understanding of the molecular mechanisms of peripheral circuit formation. In this chapter we provide a detailed methodology to characterize class 3 semaphorin-mediated effects on peripheral sensory and motor axon pathfinding and connectivity during embryonic development.

  2. Morphometric analysis of Mauthner axon cytoskeletal components in adult and subadult fish.

    Science.gov (United States)

    Alfei, L; Medolago-Albani, L; Zezze, G M; Stefanelli, A

    1992-01-01

    A previous cytoskeletal analysis on trout MA during developmental stages demonstrated, during the subadult stages, neurofilaments (NF) as main components as expressed by the high values of neurofilament to microtubules (MT) ratio which was found to be of the order of 300:1. Since the MA cytoskeletal composition is not known in the adult fish, the MA cytoskeletal composition has been compared to other axons of much smaller diameter of the fasciculus longitudinalis medialis (flm) among which the MA run in the ventral spinal cord. The following parameters were measured on conventional electron microscopy in MA and flm axons cross sections micrographs by means of a computer linked graphic tablet (Apple II): axonal caliber, number of microtubules (MT), microtubular (MT/microns2) and neurofilament (NF/microns2) densities. The analysis of these parameters demonstrated that neurofilaments are the main architectural components in the adult and subadult fish MA and flm axons. However, MA cytoskeletal composition differs from the other flm axons because of its particular very high ratio of neurofilaments to microtubules. The inverse relationship of axonal caliber to microtubular density, previously found in the trout during developmental stages and suggested also for many other vertebrate species, was further confirmed for flm axons which, with calibers 10 times smaller than MA, exhibit a microtubular density 10 times larger.

  3. EFN-4 functions in LAD-2-mediated axon guidance in Caenorhabditis elegans.

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    Dong, Bingyun; Moseley-Alldredge, Melinda; Schwieterman, Alicia A; Donelson, Cory J; McMurry, Jonathan L; Hudson, Martin L; Chen, Lihsia

    2016-04-01

    During development of the nervous system, growing axons rely on guidance molecules to direct axon pathfinding. A well-characterized family of guidance molecules are the membrane-associated ephrins, which together with their cognate Eph receptors, direct axon navigation in a contact-mediated fashion. InC. elegans, the ephrin-Eph signaling system is conserved and is best characterized for their roles in neuroblast migration during early embryogenesis. This study demonstrates a role for the C. elegans ephrin EFN-4 in axon guidance. We provide both genetic and biochemical evidence that is consistent with the C. elegans divergent L1 cell adhesion molecule LAD-2 acting as a non-canonical ephrin receptor to EFN-4 to promote axon guidance. We also show that EFN-4 probably functions as a diffusible factor because EFN-4 engineered to be soluble can promote LAD-2-mediated axon guidance. This study thus reveals a potential additional mechanism for ephrins in regulating axon guidance and expands the repertoire of receptors by which ephrins can signal.

  4. Differential expression of axon-sorting molecules in mouse olfactory sensory neurons.

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    Ihara, Naoki; Nakashima, Ai; Hoshina, Naosuke; Ikegaya, Yuji; Takeuchi, Haruki

    2016-08-01

    In the mouse olfactory system, the axons of olfactory sensory neurons that express the same type of odorant receptor (OR) converge to a specific set of glomeruli in the olfactory bulb (OB). It is widely accepted that expressed OR molecules instruct glomerular segregation by regulating the expression of axon-sorting molecules. Although the relationship between the expression of axon-sorting molecules and OR types has been analyzed in detail, those between the expressions of axon-sorting molecules remain to be elucidated. Here we collected the expression profiles of four axon-sorting molecules from a large number of glomeruli in the OB. These molecules demonstrated position-independent mosaic expressions, but their patterns were not identical in the OB. Comparing their expressions identified positive and negative correlations between several pairs of genes even though they showed various expressions. Furthermore, the principal component analysis revealed that the factor loadings in the principal component 1, which explain the largest amount of variation, were most likely to reflect the degree of the cyclic nucleotide-gated (CNG) channel dependence on the expression of axon-sorting molecules. Thus, neural activity generated through the CNG channel is a major component in the generation of a wide variety of expressions of axon-sorting molecules in glomerular segregation.

  5. Stimulation of nicotinamide adenine dinucleotide biosynthetic pathways delays axonal degeneration after axotomy.

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    Sasaki, Yo; Araki, Toshiyuki; Milbrandt, Jeffrey

    2006-08-16

    Axonal degeneration occurs in many neurodegenerative diseases and after traumatic injury and is a self-destructive program independent from programmed cell death. Previous studies demonstrated that overexpression of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1) or exogenous application of nicotinamide adenine dinucleotide (NAD) can protect axons of cultured dorsal root ganglion (DRG) neurons from degeneration caused by mechanical or neurotoxic injury. In mammalian cells, NAD can be synthesized from multiple precursors, including tryptophan, nicotinic acid, nicotinamide, and nicotinamide riboside (NmR), via multiple enzymatic steps. To determine whether other components of these NAD biosynthetic pathways are capable of delaying axonal degeneration, we overexpressed each of the enzymes involved in each pathway and/or exogenously administered their respective substrates in DRG cultures and assessed their capacity to protect axons after axotomy. Among the enzymes tested, Nmnat1 had the strongest protective effects, whereas nicotinamide phosphoribosyl transferase and nicotinic acid phosphoribosyl transferase showed moderate protective activity in the presence of their substrates. Strong axonal protection was also provided by Nmnat3, which is predominantly located in mitochondria, and an Nmnat1 mutant localized to the cytoplasm, indicating that the subcellular location of NAD production is not crucial for protective activity. In addition, we showed that exogenous application of the NAD precursors that are the substrates of these enzymes, including nicotinic acid mononucleotide, nicotinamide mononucleotide, and NmR, can also delay axonal degeneration. These results indicate that stimulation of NAD biosynthetic pathways via a variety of interventions may be useful in preventing or delaying axonal degeneration.

  6. Serial Section Registration of Axonal Confocal Microscopy Datasets for Long-Range Neural Circuit Reconstruction

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    Hogrebe, Luke; Paiva, Antonio R.; Jurrus, Elizabeth R.; Christensen, Cameron; Bridge, Michael; Dai, Li; Pfeiffer, Rebecca; Hof, Patrick; Roysam, Badrinath; Korenberg, Julie; Tasdizen, Tolga

    2012-06-15

    In the context of long-range digital neural circuit reconstruction, this paper investigates an approach for registering axons across histological serial sections. Tracing distinctly labeled axons over large distances allows neuroscientists to study very explicit relationships between the brain's complex interconnects and, for example, diseases or aberrant development. Large scale histological analysis requires, however, that the tissue be cut into sections. In immunohistochemical studies thin sections are easily distorted due to the cutting, preparation, and slide mounting processes. In this work we target the registration of thin serial sections containing axons. Sections are first traced to extract axon centerlines, and these traces are used to define registration landmarks where they intersect section boundaries. The trace data also provides distinguishing information regarding an axon's size and orientation within a section. We propose the use of these features when pairing axons across sections in addition to utilizing the spatial relationships amongst the landmarks. The global rotation and translation of an unregistered section are accounted for using a random sample consensus (RANSAC) based technique. An iterative nonrigid refinement process using B-spline warping is then used to reconnect axons and produce the sought after connectivity information.

  7. Producción de IFN−γ en cultivos de linfocitos humanos por efecto de los extractos metanólicos de cuatro ecotipos de Lepidium peruvianum, Chacón (Brassicaceae

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    Libertad Alzamora

    2013-05-01

    Full Text Available Se estudió la actividad inmunoduladora sobre cultivos de linfocitos T humanos de sangre periférica. Se evaluó la producción de IFN−γ inducida por los extractos metanólicos (EM de los ecotipos blanco, negro, rojo y morado de Lepidium peruvianum (conocida también como Lepidium meyenii Walp. maca. Luego de cultivar los linfocitos con los respectivos EM de maca durante 14 horas sólo el EM del ecotipo morado indujo la producción significativa de IFN−γ cuantificada mediante Elispot. El extracto metanólico del ecotipo morado de maca posee propiedades inmunoestimuladoras importantes, desencadenando la activación de linfocitos T humanos.

  8. Regenerative Responses and Axon Pathfinding of Retinal Ganglion Cells in Chronically Injured Mice

    Science.gov (United States)

    Yungher, Benjamin J.; Ribeiro, Márcio; Park, Kevin K.

    2017-01-01

    Purpose Enhanced regeneration of retinal ganglion cell (RGC) axons can be achieved by modification of numerous neuronal-intrinsic factors. However, axon growth initiation and the pathfinding behavior of these axons after traumatic injury remain poorly understood outside of acute injury paradigms, despite the clinical relevance of more chronic settings. We therefore examined RGC axon regeneration following therapeutic delivery that is postponed until 2 months after optic nerve crush injury. Methods Optic nerve regeneration was induced by virally mediated (adeno-associated virus) ciliary neurotrophic factor (AAV-CNTF) administered either immediately or 56 days after optic nerve crush in wild-type or Bax knockout (KO) mice. Retinal ganglion nerve axon regeneration was assessed 21 and 56 days after viral injection. Immunohistochemical analysis of RGC injury signals and extrinsic factors in the optic nerve were also examined at 5 and 56 days post crush. Results In addition to sustained expression of injury response proteins in surviving RGCs, we observe axon regrowth in wild-type and apoptosis-deficient Bax KO mice following AAV-CNTF treatment. Fewer instances of aberrant axon growth are seen, at least in the area near the lesion site, in animals given treatment 56 days after crush injury compared to the animals given treatment immediately after injury. We also find evidence of long distance growth into a visual target in Bax KO mice despite postponed initiation of this regenerative program. Conclusions These studies provide evidence against an intrinsic critical period for RGC axon regeneration or degradation of injury signals. Regeneration results from Bax KO mice imply highly sustained regenerative capacity in RGCs, highlighting the importance of long-lasting neuroprotective strategies as well as of RGC axon guidance research in chronically injured animals. PMID:28324115

  9. Midbrain dopaminergic axons are guided longitudinally through the diencephalon by Slit/Robo signals.

    Science.gov (United States)

    Dugan, James P; Stratton, Andrea; Riley, Hilary P; Farmer, W Todd; Mastick, Grant S

    2011-01-01

    Dopaminergic neurons from the ventral mesencephalon/diencephalon (mesodiencephalon) form vital pathways constituting the majority of the brain's dopamine systems. Mesodiencephalic dopaminergic (mdDA) neurons extend longitudinal projections anteriorly through the diencephalon, ascending toward forebrain targets. The mechanisms by which mdDA axons initially navigate through the diencephalon are poorly understood. Recently the Slit family of secreted axon guidance proteins, and their Robo receptors, have been identified as important guides for descending longitudinal axons. To test the potential roles of Slit/Robo guidance in ascending trajectories, we examined tyrosine hydroxylase-positive (TH+) projections from mdDA neurons in mutant mouse embryos. We found that mdDA axons grow out of and parallel to Slit-positive ventral regions within the diencephalon, and that subsets of the mdDA axons likely express Robo1 and possibly also Robo2. Slit2 was able to directly inhibit TH axon outgrowth in explant co-culture assays. The mdDA axons made significant pathfinding errors in Slit1/2 and Robo1/2 knockout mice, including spreading out in the diencephalon to form a wider tract. The wider tract resulted from a combination of invasion of the ventral midline, consistent with Slit repulsion, but also axons wandering dorsally, away from the ventral midline. Aberrant dorsal trajectories were prominent in Robo1 and Robo1/2 knockout mice, suggesting that an aspect of Robo receptor function is Slit-independent. These results indicate that Slit/Robo signaling is critical during the initial establishment of dopaminergic pathways, with roles in the dorsoventral positioning and precise pathfinding of these ascending longitudinal axons.

  10. Experience-driven axon retraction in the pharmacologically inactivated visual cortex does not require synaptic transmission.

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    Kana Watanabe

    Full Text Available BACKGROUND: Experience during early postnatal development plays an important role in the refinement of specific neural connections in the brain. In the mammalian visual system, altered visual experiences induce plastic adaptation of visual cortical responses and guide rearrangements of afferent axons from the lateral geniculate nucleus. Previous studies using visual deprivation demonstrated that the afferents serving an open eye significantly retract when cortical neurons are pharmacologically inhibited by applying a gamma-aminobutyric acid type A receptor agonist, muscimol, whereas those serving a deprived eye are rescued from retraction, suggesting that presynaptic activity can lead to the retraction of geniculocortical axons in the absence of postsynaptic activity. Because muscimol application suppresses the spike activity of cortical neurons leaving transmitter release intact at geniculocortical synapses, local synaptic interaction may underlie the retraction of active axons in the inhibited cortex. METHOD AND FINDINGS: New studies reported here determined whether experience-driven axon retraction can occur in the visual cortex inactivated by blocking synaptic inputs. We inactivated the primary visual cortex of kittens by suppressing synaptic transmission with cortical injections of botulinum neurotoxin type E, which cleaves a synaptic protein, SNAP-25, and blocks transmitter release, and examined the geniculocortical axon morphology in the animals with normal vision and those deprived of vision binocularly. We found that afferent axons in the animals with normal vision showed a significant retraction in the inactivated cortex, as similarly observed in the muscimol-treated cortex, whereas the axons in the binocularly deprived animals were preserved. CONCLUSIONS: Therefore, the experience-driven axon retraction in the inactivated cortex can proceed in the absence of synaptic transmission. These results suggest that presynaptic mechanisms play

  11. The Microtubule Regulatory Protein Stathmin Is Required to Maintain the Integrity of Axonal Microtubules in Drosophila.

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    Jason E Duncan

    Full Text Available Axonal transport, a form of long-distance, bi-directional intracellular transport that occurs between the cell body and synaptic terminal, is critical in maintaining the function and viability of neurons. We have identified a requirement for the stathmin (stai gene in the maintenance of axonal microtubules and regulation of axonal transport in Drosophila. The stai gene encodes a cytosolic phosphoprotein that regulates microtubule dynamics by partitioning tubulin dimers between pools of soluble tubulin and polymerized microtubules, and by directly binding to microtubules and promoting depolymerization. Analysis of stai function in Drosophila, which has a single stai gene, circumvents potential complications with studies performed in vertebrate systems in which mutant phenotypes may be compensated by genetic redundancy of other members of the stai gene family. This has allowed us to identify an essential function for stai in the maintenance of the integrity of axonal microtubules. In addition to the severe disruption in the abundance and architecture of microtubules in the axons of stai mutant Drosophila, we also observe additional neurological phenotypes associated with loss of stai function including a posterior paralysis and tail-flip phenotype in third instar larvae, aberrant accumulation of transported membranous organelles in stai deficient axons, a progressive bang-sensitive response to mechanical stimulation reminiscent of the class of Drosophila mutants used to model human epileptic seizures, and a reduced adult lifespan. Reductions in the levels of Kinesin-1, the primary anterograde motor in axonal transport, enhance these phenotypes. Collectively, our results indicate that stai has an important role in neuronal function, likely through the maintenance of microtubule integrity in the axons of nerves of the peripheral nervous system necessary to support and sustain long-distance axonal transport.

  12. Robust regeneration of CNS axons through a track depleted of CNS glia.

    Science.gov (United States)

    Moon, L D; Brecknell, J E; Franklin, R J; Dunnett, S B; Fawcett, J W

    2000-01-01

    Transected CNS axons do not regenerate spontaneously but may do so if given an appropriate environment through which to grow. Since molecules associated with CNS macroglia are thought to be inhibitory to axon regeneration, we have tested the hypothesis that removing these cell types from an area of brain will leave an environment more permissive for axon regeneration. Adult rats received unilateral knife cuts of the nigrostriatal tract and ethidium bromide (EB) was used to create a lesion devoid of astrocytes, oligodendrocytes, intact myelin sheaths, and NG2 immunoreactive cells from the site of the knife cut to the ipsilateral striatum (a distance of 6 mm). The regenerative response and the EB lesion environment was examined with immunostaining and electron microscopy at different timepoints following surgery. We report that large numbers of dopaminergic nigral axons regenerated for over 4 mm through EB lesions. At 4 days postlesion dopaminergic sprouting was maximal and the axon growth front had reached the striatum, but there was no additional growth into the striatum after 7 days. Regenerating axons did not leave the EB lesion to form terminals in the striatum, there was no recovery of function, and the end of axon growth correlated with increasing glial immunoreactivity around the EB lesion. We conclude that the removal of CNS glia promotes robust axon regeneration but that this becomes limited by the reappearance of nonpermissive CNS glia. These results suggest, first, that control of the glial reaction is likely to be an important feature in brain repair and, second, that reports of axon regeneration must be interpreted with caution since extensive regeneration can occur simply as a result of a major glia-depleting lesion, rather than as the result of some other specific intervention.

  13. Hematopoietic progenitors express myelin basic protein and ensheath axons in Shiverer brain.

    Science.gov (United States)

    Goolsby, James; Makar, Tapas; Dhib-Jalbut, Suhayl; Bever, Christopher T; Pessac, Bernard; Trisler, David

    2013-04-15

    Oligodendroglia are cells of the central nervous system (CNS) that form myelin sheath, which insulates neuronal axons. Neuropathologies of the CNS include dysmyelination of axons in multiple sclerosis and CNS trauma. Cell replacement is a promising but largely untested therapy for dysmyelination. Shiverer mouse, a genetic mutant that does not synthesize full-length myelin basic protein (MBP), a critical prerequisite protein in CNS myelin sheath formation, provides an unequivocal model for determining the potential of stem cells to become oligodendroglia. We demonstrate that adult wild-type mouse bone marrow stem cells can express MBP and ensheath axons when transplanted into Shiverer brain.

  14. Optic nerve fast axonal transport abnormalities in primates. Occurrence after short posterior ciliary artery occlusion.

    Science.gov (United States)

    Radius, R L

    1980-11-01

    Fast axonal transport abnormalities in primate (Aotus trivirgatus) optic nerve were studied in ten eyes at various intervals after occlusion of the lateral short posterior ciliary circulation. Evidence of focal axonal ischemia, as indicated by swelling of mitochondria and dissolution of cytoplasmic detail, was noted as early as one hour after occlusion. Accumulation of mitochondria, microvesicles, and dense bodies, indicating focal interruption of axonal transport mechanisms, was noted in eyes examined at 2, 4, and 6 hours. This accumulation of organelles was limited to the region of the lamina cribrosa. Nerve head abnormalities were not seen in two eyes studied at two weeks.

  15. Midline governs axon pathfinding by coordinating expression of two major guidance systems.

    Science.gov (United States)

    Liu, Qing-Xin; Hiramoto, Masaki; Ueda, Hitoshi; Gojobori, Takashi; Hiromi, Yasushi; Hirose, Susumu

    2009-05-15

    Formation of the neural network requires concerted action of multiple axon guidance systems. How neurons orchestrate expression of multiple guidance genes is poorly understood. Here, we show that Drosophila T-box protein Midline controls expression of genes encoding components of two major guidance systems: Frazzled, ROBO, and Slit. In midline mutant, expression of all these molecules are reduced, resulting in severe axon guidance defects, whereas misexpression of Midline induces their expression. Midline is present on the promoter regions of these genes, indicating that Midline controls transcription directly. We propose that Midline controls axon pathfinding through coordinating the two guidance systems.

  16. Axonal recovery after severe traumatic brain injury demonstrated in vivo by 1H MR spectroscopy

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    Danielsen, E.R.; Thomsen, C. [Department of Neuroradiology, Section 3023, Rigshospitalet, Copenhagen (Denmark); Christensen, P.B. [Hammel Neurocentre, Department of Neurology, Aarhus University Hospital (Denmark); Arlien-Soeborg, P. [Department of Neurology, Rigshospitalet, Copenhagen (Denmark)

    2003-10-01

    Proton magnetic resonance spectroscopy (MRS) suggested almost complete axonal recovery 21 months after trauma in a patient with severe diffuse axonal injury. MRS while the patient was comatose showed evidence of severe diffuse axonal injury in occipitoparietal white matter, but occipital grey matter was relatively spared. At 21 months N-acetylaspartate was normal. At 33 months examination showed a Functional Independence Measure of 83 and a Rancho Los Amigos Scale of Cognitive Function of 7-8, a remarkable improvement considering all the initial findings, except those of MRS. (orig.)

  17. Enzyme-instructed self-assembly of taxol promotes axonal branching

    Science.gov (United States)

    Mei, Bin; Miao, Qingqing; Tang, Anming; Liang, Gaolin

    2015-09-01

    Axonal branching is important for vertebrate neuron signaling. Taxol has a biphasic effect on axonal branching (i.e., high concentration inhibits axonal growth but low concentration restores it). To the best of our knowledge, low concentration of taxol to promote axonal branching has not been reported yet. Herein, we rationally designed a taxol derivative Fmoc-Phe-Phe-Lys(taxol)-Tyr(H2PO4)-OH (1) which could be subjected to alkaline phosphatase (ALP)-catalyzed self-assembly to form taxol nanofibers. We found that, at 10 μM, 1 has a microtubule (MT) condensation effect similar to that of taxol on mammalian cells but with more chronic toxicity than taxol on the cells. At a low concentration of 10 nM, 1 not only promoted neurite elongation as taxol did but also promoted axonal branching which was not achieved by using taxol. We propose that self-assembly of 1 along the MTs prohibited their lateral contacts and thus promoted axonal branching. Our strategy of enzyme-instructed self-assembly (EISA) of a taxol derivative provides a new tool for scientists to study the morphology of neurons, as well as their behaviours.Axonal branching is important for vertebrate neuron signaling. Taxol has a biphasic effect on axonal branching (i.e., high concentration inhibits axonal growth but low concentration restores it). To the best of our knowledge, low concentration of taxol to promote axonal branching has not been reported yet. Herein, we rationally designed a taxol derivative Fmoc-Phe-Phe-Lys(taxol)-Tyr(H2PO4)-OH (1) which could be subjected to alkaline phosphatase (ALP)-catalyzed self-assembly to form taxol nanofibers. We found that, at 10 μM, 1 has a microtubule (MT) condensation effect similar to that of taxol on mammalian cells but with more chronic toxicity than taxol on the cells. At a low concentration of 10 nM, 1 not only promoted neurite elongation as taxol did but also promoted axonal branching which was not achieved by using taxol. We propose that self-assembly of 1

  18. In vivo axonal transport deficits in a mouse model of fronto-temporal dementia

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    Tabassum Majid

    2014-01-01

    Discussion: In our study, we identified the presence of age-dependent axonal transport deficits beginning at 3 months of age in rTg4510 mice. We correlated these deficits at 3 months to the presence of hyperphosphorylated tau in the brain and the presence within the olfactory epithelium. We observed tau pathology not only in the soma of these neurons but also within the axons and processes of these neurons. Our characterization of axonal transport in this tauopathy model provides a functional time point that can be used for future therapeutic interventions.

  19. Extracellular matrix molecules play diverse roles in the growth and guidance of central nervous system axons

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    M.A. Pires-Neto

    1999-05-01

    Full Text Available Axon growth and guidance represent complex biological processes in which probably intervene diverse sets of molecular cues that allow for the appropriate wiring of the central nervous system (CNS. The extracellular matrix (ECM represents a major contributor of molecular signals either diffusible or membrane-bound that may regulate different stages of neural development. Some of the brain ECM molecules form tridimensional structures (tunnels and boundaries that appear during time- and space-regulated events, possibly playing relevant roles in the control of axon elongation and pathfinding. This short review focuses mainly on the recognized roles played by proteoglycans, laminin, fibronectin and tenascin in axonal development during ontogenesis.

  20. An Atypical SCF-like Ubiquitin Ligase Complex Promotes Wallerian Degeneration through Regulation of Axonal Nmnat2

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    Yuya Yamagishi

    2016-10-01

    Full Text Available Axon degeneration is a tightly regulated, self-destructive program that is a critical feature of many neurodegenerative diseases, but the molecular mechanisms regulating this program remain poorly understood. Here, we identify S-phase kinase-associated protein 1A (Skp1a, a core component of a Skp/Cullin/F-box (SCF-type E3 ubiquitin ligase complex, as a critical regulator of axon degeneration after injury in mammalian neurons. Depletion of Skp1a prolongs survival of injured axons in vitro and in the optic nerve in vivo. We demonstrate that Skp1a regulates the protein level of the nicotinamide adenine dinucleotide (NAD+ synthesizing enzyme nicotinamide mononucleotide adenylyltransferase 2 (Nmnat2 in axons. Loss of axonal Nmnat2 contributes to a local ATP deficit that triggers axon degeneration. Knockdown of Skp1a elevates basal levels of axonal Nmnat2, thereby delaying axon degeneration through prolonged maintenance of axonal ATP. Consistent with Skp1a functioning through regulation of Nmnat2, Skp1a knockdown fails to protect axons from Nmnat2 knockdown. These results illuminate the molecular mechanism underlying Skp1a-dependent axonal destruction.

  1. Novel RNA- and FMRP-binding protein TRF2-S regulates axonal mRNA transport and presynaptic plasticity.

    Science.gov (United States)

    Zhang, Peisu; Abdelmohsen, Kotb; Liu, Yong; Tominaga-Yamanaka, Kumiko; Yoon, Je-Hyun; Ioannis, Grammatikakis; Martindale, Jennifer L; Zhang, Yongqing; Becker, Kevin G; Yang, In Hong; Gorospe, Myriam; Mattson, Mark P

    2015-11-20

    Despite considerable evidence that RNA-binding proteins (RBPs) regulate mRNA transport and local translation in dendrites, roles for axonal RBPs are poorly understood. Here we demonstrate that a non-telomeric isoform of telomere repeat-binding factor 2 (TRF2-S) is a novel RBP that regulates axonal plasticity. TRF2-S interacts directly with target mRNAs to facilitate their axonal delivery. The process is antagonized by fragile X mental retardation protein (FMRP). Distinct from the current RNA-binding model of FMRP, we show that FMRP occupies the GAR domain of TRF2-S protein to block the assembly of TRF2-S-mRNA complexes. Overexpressing TRF2-S and silencing FMRP promotes mRNA entry to axons and enhances axonal outgrowth and neurotransmitter release from presynaptic terminals. Our findings suggest a pivotal role for TRF2-S in an axonal mRNA localization pathway that enhances axon outgrowth and neurotransmitter release.

  2. Identifying motor and sensory myelinated axons in rabbit peripheral nerves by histochemical staining for carbonic anhydrase and cholinesterase activities

    Science.gov (United States)

    Riley, Danny A.; Sanger, James R.; Matloub, Hani S.; Yousif, N. John; Bain, James L. W.

    1988-01-01

    Carbonic anhydrase (CA) and cholinesterase (CE) histochemical staining of rabbit spinal nerve roots and dorsal root ganglia demonstrated that among the reactive myeliated axons, with minor exceptions, sensory axons were CA positive and CE negative whereas motor axons were CA negative and CE positive. The high specificity was achieved by adjusting reaction conditions to stain subpopulations of myelinated axons selectively while leaving 50 percent or so unstained. Fixation with glutaraldehyde appeared necessary for achieving selectivity. Following sciatic nerve transection, the reciprocal staining pattern persisted in damaged axons and their regenerating processes which formed neuromas within the proximal nerve stump. Within the neuromas, CA-stained sensory processes were elaborated earlier and in greater numbers than CE-stained regenerating motor processes. The present results indicate that histochemical axon typing can be exploited to reveal heterogeneous responses of motor and sensory axons to injury.

  3. Guidance of Drosophila Mushroom Body Axons Depends upon DRL-Wnt Receptor Cleavage in the Brain Dorsomedial Lineage Precursors

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    Elodie Reynaud

    2015-05-01

    Full Text Available In vivo axon pathfinding mechanisms in the neuron-dense brain remain relatively poorly characterized. We study the Drosophila mushroom body (MB axons, whose α and β branches connect to different brain areas. We show that the Ryk family WNT5 receptor, DRL (derailed, which is expressed in the dorsomedial lineages, brain structure precursors adjacent to the MBs, is required for MB α branch axon guidance. DRL acts to capture and present WNT5 to MB axons rather than transduce a WNT5 signal. DRL’s ectodomain must be cleaved and shed to guide α axons. DRL-2, another Ryk, is expressed within MB axons and functions as a repulsive WNT5 signaling receptor. Finally, our biochemical data support the existence of a ternary complex composed of the cleaved DRL ectodomain, WNT5, and DRL-2. Thus, the interaction of MB-extrinsic and -intrinsic Ryks via their common ligand acts to guide MB α axons.

  4. Reduced axonal localization of a Caps2 splice variant impairs axonal release of BDNF and causes autistic-like behavior in mice.

    Science.gov (United States)

    Sadakata, Tetsushi; Shinoda, Yo; Oka, Megumi; Sekine, Yukiko; Sato, Yumi; Saruta, Chihiro; Miwa, Hideki; Tanaka, Mika; Itohara, Shigeyoshi; Furuichi, Teiichi

    2012-12-18

    Ca(2)(+)-dependent activator protein for secretion 2 (CAPS2 or CADPS2) potently promotes the release of brain-derived neurotrophic factor (BDNF). A rare splicing form of CAPS2 with deletion of exon3 (dex3) was identified to be overrepresented in some patients with autism. Here, we generated Caps2-dex3 mice and verified a severe impairment in axonal Caps2-dex3 localization, contributing to a reduction in BDNF release from axons. In addition, circuit connectivity, measured by spine and interneuron density, was diminished globally. The collective effect of reduced axonal BDNF release during development was a striking and selective repertoire of deficits in social- and anxiety-related behaviors. Together, these findings represent a unique mouse model of a molecular mechanism linking BDNF-mediated coordination of brain development to autism-related behaviors and patient genotype.

  5. Axonal plasticity elicits long-term changes in oligodendroglia and myelinated fibers

    DEFF Research Database (Denmark)

    Drøjdahl, Nina; Nielsen, Helle Hvilsted; Gardi, Jonathan E;

    2010-01-01

    Axons are linked to induction of myelination during development and to the maintenance of myelin and myelinated tracts in the adult CNS. Currently, it is unknown whether and how axonal plasticity in adult CNS impacts the myelinating cells and their precursors. In this article, we report that newly...... formed axonal sprouts are able to induce a protracted myelination response in adult CNS. We show that newly formed axonal sprouts, induced by lesion of the entorhino-hippocampal perforant pathway, have the ability to induce a myelination response in stratum radiatum and lucidum CA3. The lesion resulted...... in significant recruitment of newly formed myelinating cells, documented by incorporation of the proliferation marker bromodeoxyuridine into chondroitin sulphate NG2 expressing cells in stratum radiatum and lucidum CA3 early after lesion, and the occurrence of a 28% increase in the number of oligodendrocytes...

  6. CSF inflammation and axonal damage are increased and correlate in progressive multiple sclerosis

    DEFF Research Database (Denmark)

    Romme Christensen, Jeppe; Börnsen, Lars; Khademi, Mohsen;

    2013-01-01

    BACKGROUND: The mechanism underlying disease progression in progressive multiple sclerosis (MS) is uncertain. Pathological studies found widespread inflammation in progressive MS brains correlating with disease progression and axonal damage. OBJECTIVES: To study cerebrospinal fluid (CSF) biomarkers...

  7. Microtubule stabilization reduces scarring and causes axon regeneration after spinal cord injury

    NARCIS (Netherlands)

    F. Hellal (Farida); A. Hurtado (Andres); J. Ruschel (Jörg); K.C. Flynn (Kevin); C.J. Laskowski (Claudia); M. Umlauf (Martina); L.C. Kapitein (Lukas); D. Strikis (Dinara); V. Lemmon (Vance); J. Bixby (John); C.C. Hoogenraad (Casper); F. Bradke (Frank)

    2011-01-01

    textabstractHypertrophic scarring and poor intrinsic axon growth capacity constitute major obstacles for spinal cord repair. These processes are tightly regulated by microtubule dynamics. Here, moderate microtubule stabilization decreased scar formation after spinal cord injury in rodents through va

  8. Axonal degeneration stimulates the formation of NG2+ cells and oligodendrocytes in the mouse

    DEFF Research Database (Denmark)

    Nielsen, Helle Hvilsted; Ladeby, Rune; Drøjdahl, Nina;

    2006-01-01

    Proliferation of the adult NG2-expressing oligodendrocyte precursor cells has traditionally been viewed as a remyelination response ensuing from destruction of myelin and oligodendrocytes, and not to the axonal pathology that is also a characteristic of demyelinating disease. To better understand...... the response of the NG2+ cells to the different components of demyelinating pathology, we investigated the response of adult NG2+ cells to axonal degeneration in the absence of primary myelin or oligodendrocyte pathology. Axonal degeneration was induced in the hippocampal dentate gyrus of adult mice...... by transection of the entorhino-dentate perforant path projection. The acutely induced degeneration of axons and terminals resulted in a prompt response of NG2+ cells, consisting of morphological transformation, cellular proliferation, and upregulation of NG2 expression days 2-3 after surgery. This was followed...

  9. Lentiviral vectors express chondroitinase ABC in cortical projections and promote sprouting of injured corticospinal axons.

    Science.gov (United States)

    Zhao, Rong-Rong; Muir, Elizabeth M; Alves, João Nuno; Rickman, Hannah; Allan, Anna Y; Kwok, Jessica C; Roet, Kasper C D; Verhaagen, Joost; Schneider, Bernard L; Bensadoun, Jean-Charles; Ahmed, Sherif G; Yáñez-Muñoz, Rafael J; Keynes, Roger J; Fawcett, James W; Rogers, John H

    2011-09-30

    Several diseases and injuries of the central nervous system could potentially be treated by delivery of an enzyme, which might most effectively be achieved by gene therapy. In particular, the bacterial enzyme chondroitinase ABC is beneficial in animal models of spinal cord injury. We have adapted the chondroitinase gene so that it can direct secretion of active chondroitinase from mammalian cells, and inserted it into lentiviral vectors. When injected into adult rat brain, these vectors lead to extensive secretion of chondroitinase, both locally and from long-distance axon projections, with activity persisting for more than 4 weeks. In animals which received a simultaneous lesion of the corticospinal tract, the vector reduced axonal die-back and promoted sprouting and short-range regeneration of corticospinal axons. The same beneficial effects on damaged corticospinal axons were observed in animals which received the chondroitinase lentiviral vector directly into the vicinity of a spinal cord lesion.

  10. Spy1 Protein Mediates Phosphorylation and Degradation of SCG10 Protein in Axonal Degeneration*

    Science.gov (United States)

    Liu, Yonghua; Wang, Youhua; Chen, Ying; Li, Xiaohong; Yang, Jiao; Liu, Yang; Shen, Aiguo

    2015-01-01

    Axon loss is a destructive consequence of a wide range of neurological diseases without a clearly defined mechanism. Recent data demonstrate that SCG10 is a novel axonal maintenance factor and that rapid SCG10 loss after injury requires JNK activity; how JNK induces degradation of SCG10 is not well known. Here we showed that SCG10 was a binding partner of Spy1, a Speedy/RINGO family protein, which participated in cellular response to sciatic nerve injury. During the early stage of axonal injury, Spy1 expression was inversely correlated with SCG10. Spy1 mediated SCG10 phosphorylation and degradation partly in a JNK-dependent manner. Inhibition of Spy1 attenuated SCG10 phosphorylation and delayed injury-induced axonal degeneration. Taken together, these data suggest that Spy1 is an important regulator of SCG10 and can be targeted in future axo-protective therapeutics. PMID:25869138

  11. Vertebrate Fidgetin Restrains Axonal Growth by Severing Labile Domains of Microtubules

    Directory of Open Access Journals (Sweden)

    Lanfranco Leo

    2015-09-01

    Full Text Available Individual microtubules (MTs in the axon consist of a stable domain that is highly acetylated and a labile domain that is not. Traditional MT-severing proteins preferentially cut the MT in the stable domain. In Drosophila, fidgetin behaves in this fashion, with targeted knockdown resulting in neurons with a higher fraction of acetylated (stable MT mass in their axons. Conversely, in a fidgetin knockout mouse, the fraction of MT mass that is acetylated is lower than in the control animal. When fidgetin is depleted from cultured rodent neurons, there is a 62% increase in axonal MT mass, all of which is labile. Concomitantly, there are more minor processes and a longer axon. Together with experimental data showing that vertebrate fidgetin targets unacetylated tubulin, these results indicate that vertebrate fidgetin (unlike its fly ortholog regulates neuronal development by tamping back the expansion of the labile domains of MTs.

  12. Significance of transcytosis in Alzheimer's disease: BACE1 takes the scenic route to axons.

    Science.gov (United States)

    Buggia-Prévot, Virginie; Thinakaran, Gopal

    2015-08-01

    Neurons have developed elaborate mechanisms for sorting of proteins to their destination in dendrites and axons as well as dynamic local trafficking. Recent evidence suggests that polarized axonal sorting of β-site converting enzyme 1 (BACE1), a type I transmembrane aspartyl protease involved in Alzheimer's disease (AD) pathogenesis, entails an unusual journey. In hippocampal neurons, BACE1 internalized from dendrites is conveyed in recycling endosomes via unidirectional retrograde transport towards the soma and sorted to axons where BACE1 becomes enriched. In comparison to other transmembrane proteins that undergo transcytosis or elimination in somatodendritic compartment, vectorial transport of internalized BACE1 in dendrites is unique and intriguing. Dysfunction of protein transport contributes to pathogenesis of AD and other neurodegenerative diseases. Therefore, characterization of BACE1 transcytosis is an important addition to the multiple lines of evidence that highlight the crucial role played by endosomal trafficking pathway as well as axonal sorting mechanisms in AD pathogenesis.

  13. Osteomielitis por salmonella

    Directory of Open Access Journals (Sweden)

    Alicia Velázquez Pérez

    2014-08-01

    Full Text Available Se presenta el caso de una paciente femenina de color blanco y dos años de edad, con diagnóstico prenatal de sicklemia, que desde edades tempranas tiene problemas de la enfermedad. Ingresó en esta ocasión por una de las complicaciones infecciosas que ocasiona este padecimiento, una osteomielitis del húmero izquierdo, aislándose el germen en el hemocultivo realizado, una salmonella. Necesitó de tratamiento enérgico y prolongado; se obtuvo un resultado satisfactorio en la evolución de la enfermedad y se sigue sistemáticamente por consulta externa en la actualidad

  14. Erosión en la costa patagónica por cambio climático

    Directory of Open Access Journals (Sweden)

    R.R. Kokot

    2004-12-01

    Full Text Available El área costera patagónica presenta evidencias de erosión en casi toda su extensión. Las causas de la erosión son consecuencia en mayor medida, del cambio climático ocurrido a partir del último período glaciario. La erosión se da primero por falta de acumulación directa (la carga de los ríos no llega a la línea de costa y segundo por el efecto de erosión inducida, ya que al no saturarse los flujos costeros por el aporte fluvial, estos lo hacen a expensas de la erosión de los afloramientos. Actualmente, en los principales ríos patagónicos no se dan las condiciones hidráulicas para el transporte de gravas. La falta de aporte por parte de los ríos actuales indica que las formas de acreción presentes en la faja litoral, constituidas por esa fracción clástica, corresponden a formas relícticas. La condición de formación de esos depósitos se daba en períodos en que los caudales imperantes estaban en relación con los tamaños de cauce. El nivel de base de los ríos del Pleistoceno, se halló en diversas oportunidades por debajo del nivel actual, alcanzando unos 150 m por debajo del nivel presente. Por ello es común la presencia de líneas de costa sumergidas con sedimentos aportados por los ríos durante esos períodos. La presencia de cañones submarinos en continuidad con cauces de ríos actualmente efímeros o permanentes de baja capacidad erosiva, indica cambios en el nivel del mar asociados a cambios climáticos.

  15. Sodium movements in perfused squid giant axons. Passive fluxes.

    Science.gov (United States)

    Rojas, E; Canessa-Fischer, M

    1968-08-01

    Sodium movements in internally perfused giant axons from the squid Dosidicus gigas were studied with varying internal sodium concentrations and with fluoride as the internal anion. It was found that as the internal concentration of sodium was increased from 2 to 200 mM the resting sodium efflux increased from 0.09 to 34.0 pmoles/cm(2)sec and the average resting sodium influx increased from 42.9 to 64.5 pmoles/cm(2)sec but this last change was not statistically significant. When perfusing with a mixture of 500 mM K glutamate and 100 mM Na glutamate the resting efflux was 10 +/- 3 pmoles/cm(2)sec and 41 +/- 10 pmoles/cm(2)sec for sodium influx. Increasing the internal sodium concentration also increased both the extra influx and the extra efflux of sodium due to impulse propagation. At any given internal sodium concentration the net extra influx was about 5 pmoles/cm(2)impulse. This finding supports the notion that the inward current generated in a propagated action potential can be completely accounted for by movements of sodium.

  16. Detection of functional homotopy in traumatic axonal injury

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Gao, Lei; Xie, Kai; Zhan, Jie; Luo, Xiaoping; Wang, Huifang; Zhang, Huifang; Zhao, Jing; Zhou, Fuqing; Zeng, Xianjun; He, Laichang; He, Yulin; Gong, Honghan [Nanchang University, Department of Radiology, The First Affiliated Hospital, Nanchang City, Jiangxi (China)

    2017-01-15

    This study aimed to explore the interhemispheric intrinsic connectivity in traumatic axonal injury (TAI) patients. Twenty-one patients with TAI (14 males, seven females; mean age, 38.71 ± 15.25 years) and 22 well-matched healthy controls (16 males, six females; mean age, 38.50 ± 13.82 years) were recruited, and from them we obtained resting-state fMRI data. Interhemispheric coordination was examined using voxel-mirrored homotopic connectivity (VMHC) and seed-based functional connectivity analysis was performed. We observed significantly decreased VMHC in a number of regions in TAI patients, including the prefrontal, temporal, occipital, parietal, and posterior cingulate cortices, thalami and cerebellar posterior lobes. Subsequent seed-based functional connectivity analysis revealed widely disrupted functional connectivity between the regions of local homotopic connectivity deficits and other areas of the brain, particularly the areas subserving the default, salience, integrative, and executive systems. The lower VMHC of the inferior frontal gyrus and basal ganglia, thalamus, and caudate were significant correlated with the Beck Depression Inventory score, Clinical Dementia Rating score, and Mini-Mental State Examination score, respectively. TAI is associated with regionally decreased interhemispheric interactions and extensively disrupted seed-based functional connectivity, generating further evidence of diffuse disconnection being associated with clinical symptoms in TAI patients. (orig.)

  17. Single rodent mesohabenular axons release glutamate and GABA

    Science.gov (United States)

    Root, David H.; Mejias-Aponte, Carlos; Zhang, Shiliang; Wang, Huiling; Hoffman, Alexander F.; Lupica, Carl R.; Morales, Marisela

    2016-01-01

    The lateral habenula (LHb) is involved in reward, aversion, addiction, and depression, through descending interactions with several brain structures, including the ventral tegmental area (VTA). VTA provides reciprocal inputs to LHb, but their actions are unclear. Here we show that the majority of rat and mouse VTA neurons innervating LHb co-express markers for both glutamate-signaling (vesicular glutamate transporter 2, VGluT2) and GABA-signaling (glutamate decarboxylase, GAD; and vesicular GABA transporter, VGaT). A single axon from these mesohabenular neurons co-expresses VGluT2-protein and VGaT-protein, and surprisingly establishes symmetric and asymmetric synapses on LHb neurons. In LHb slices, light activation of mesohabenular fibers expressing channelrhodopsin-2 (ChR2) driven by VGluT2 or VGaT promoters elicits release of both glutamate and GABA onto single LHb neurons. In vivo light-activation of mesohabenular terminals inhibits or excites LHb neurons. Our findings reveal an unanticipated type of VTA neuron that co-transmits glutamate and GABA, and provides the majority of mesohabenular inputs. PMID:25242304

  18. Reduced axonal localization of a Caps2 splice variant impairs axonal release of BDNF and causes autistic-like behavior in mice

    OpenAIRE

    Sadakata, Tetsushi; Shinoda, Yo; Oka, Megumi; Sekine, Yukiko; Sato, Yumi; Saruta, Chihiro; Miwa, Hideki; Tanaka, Mika; Itohara, Shigeyoshi; Furuichi, Teiichi

    2012-01-01

    Ca2+-dependent activator protein for secretion 2 (CAPS2 or CADPS2) potently promotes the release of brain-derived neurotrophic factor (BDNF). A rare splicing form of CAPS2 with deletion of exon3 (dex3) was identified to be overrepresented in some patients with autism. Here, we generated Caps2-dex3 mice and verified a severe impairment in axonal Caps2-dex3 localization, contributing to a reduction in BDNF release from axons. In addition, circuit connectivity, measured by spine and interneuron ...

  19. Greater loss of axons in primary progressive multiple sclerosis plaques compared to secondary progressive disease.

    Science.gov (United States)

    Tallantyre, E C; Bø, L; Al-Rawashdeh, O; Owens, T; Polman, C H; Lowe, J; Evangelou, N

    2009-05-01

    The pathological substrate of progressive disability in multiple sclerosis is hypothesized to be axonal loss. Differences in the demographic, pathological and radiological features of patients with primary progressive compared with secondary progressive multiple sclerosis raise the question as to whether they actually represent separate clinical entities. So far, large pathological studies comparing axonal damage between primary progressive and secondary progressive multiple sclerosis have not been reported. In this clinico-pathological study we examined the cervical spinal cord in patients with primary and secondary progressive multiple sclerosis. Human cervical spinal cord was derived at autopsy from 54 patients (17 primary progressive, 30 secondary progressive and 7 controls). Tissue was stained immunohistochemically and examined to determine: (i) the number of surviving corticospinal tract axons; (ii) the extent of grey and white matter demyelination; (iii) the degree of inflammation inside and outside of lesions; and (iv) the relationship between demyelination and axonal loss. Associated clinical data was used to calculate expanded disability status scale for each patient preceding death. Motor disability in the primary progressive and secondary progressive groups was similar preceding death. Secondary progressive multiple sclerosis patients showed considerably more extensive demyelination of both the white and grey matter of the cervical spinal cord. The total number of corticospinal axons was equally low in primary progressive and secondary progressive multiple sclerosis groups versus controls. The reduction of axonal density in demyelinated regions compared to normal appearing white matter was significantly more extensive in primary progressive versus secondary progressive patients (33% reduction versus 16% reduction, P progressive multiple sclerosis with a common plaque-centred mechanism. More extensive axonal loss within areas of demyelination in primary

  20. New form of autosomal-recessive axonal hereditary sensory motor neuropathy.

    Science.gov (United States)

    Eckhardt, S M; Hicks, E M; Herron, B; Morrison, P J; Aicardi, J

    1998-09-01

    Two siblings, a male and a female, had severe axonal neuropathy and sideroblastic anemia. Despite a distinct clinical picture with areflexia, ataxia, hypotonia, optic atrophy, and progressive sensory neural hearing loss, no definite diagnosis could be reached and the older sibling died at 6 years of age of respiratory failure. It is proposed that the two affected siblings have a new form of autosomal-recessive axonal hereditary sensory motor neuropathy.