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Sample records for axonal inducida por

  1. toxicidad neuroendocrina inducida por cadmio

    Directory of Open Access Journals (Sweden)

    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.

  2. 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.

  3. Reacciones radicalarias de epoxicetonas insaturadas inducidas por titanoceno

    OpenAIRE

    Mateos Burón, Lydia

    2010-01-01

    [ES]Tesis doctoral sobre Reacciones radicalarias de epoxicetonas insaturadas inducidas por titanoceno, perteneciente al departamento de química orgánica [EN]Doctoral Thesis on the radical reactions induced by unsaturated titanocene epoxicetonas, from the organic chemistry´s departament

  4. Control de la conducta inducida por programa por sus consecuencias ambientales

    OpenAIRE

    Ardoy Cuadros, Juan

    2008-01-01

    La presente Tesis Doctoral se ha desarrollado dentro de una de las líneas de investigación desarrollada por el Departamento de Psicología Básica I de la UNED y cuyo objetivo prioritario es el estudio de las características de la conducta inducida por programa, así como el control ambiental y farmacológico de la misma. El objetivo de esta investigación, en concreto, es determinar los factores implicados en la aparición de la polidipsia inducida por programa en ratas, así como en su mantenimi...

  5. 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.

  6. 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.

  7. HIPONATREMIA INDUCIDA POR OXCARBACEPINA: UNA HIPÓTESIS FISIOPATOLÓGICA

    OpenAIRE

    Musso CG; Vilas M; Aparicio C; Bevione P; Reynaldi J; Rojas J; Jauregui R; Algranati L

    2009-01-01

    La carbamazepina y la oxcarbazepina son drogas antiepilépticas potencialmente inductoras de hiponatremia, siendo este disturbio más frecuente con ésta última.En este reporte presentamos un caso de hiponatremia inducida por oxcarbazepina, y proponemos una potencial explicación fisiopatológica para esta entidad, a la cual se la considera consecuencia de un aumento a nivel de los túmulos colectores de la reabsorción de agua libre, de la pérdida urinaria de sodio, o de ambos fenómenos combinados....

  8. 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.

  9. 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

  10. HIPONATREMIA INDUCIDA POR OXCARBACEPINA: UNA HIPÓTESIS FISIOPATOLÓGICA

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    Musso CG

    2009-01-01

    Full Text Available La carbamazepina y la oxcarbazepina son drogas antiepilépticas potencialmente inductoras de hiponatremia, siendo este disturbio más frecuente con ésta última.En este reporte presentamos un caso de hiponatremia inducida por oxcarbazepina, y proponemos una potencial explicación fisiopatológica para esta entidad, a la cual se la considera consecuencia de un aumento a nivel de los túmulos colectores de la reabsorción de agua libre, de la pérdida urinaria de sodio, o de ambos fenómenos combinados.Además, postulamos que la mayor propensión a la aparición de hiponatremia con el uso de oxcarbazepina respecto del empleo de carbamazepina podría ser consecuencia de una mayor sensibilidad de los túmulos colectores a la primera de las drogas mencionadas.

  11. 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.

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

    OpenAIRE

    Sabrina Vadalá; Débora Pellegrini; María Fernanda Verdaguer; Marcela Schrappe; José Álvarez; Julio E. Bruetman

    2014-01-01

    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 hipogluce...

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

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    Ninna Leslie Trejo-González

    2015-07-01

    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

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

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    Ninna Leslie Trejo-González

    2015-09-01

    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

  15. 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

  16. Un extracto de Punica granatum L. (BLBu sobre la apoptosis inducida por virus influenza A y B

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    Isis Casadelvalle Pérez

    2006-01-01

    Full Text Available La apoptosis ha sido ampliamente reconocida como un mecanismo intrínseco de autodestrucción en las células animales. Este fenómeno puede ser inducido por múltiples factores, entre los que se pueden citar algunos virus, que lo utilizan como vía de diseminación en el hospedero. Para contrarrestar este mecanismo se han usado extractos obtenidos de plantas con propiedades antivirales, los cuales, intuitivamente, pudieran ejercer su efecto sobre la apoptosis inducida por los virus. En el presente trabajo se estudió el efecto de un extracto natural de Punica granatum L. sobre la apoptosis inducida por dos virus: influenza A e influenza B en dos líneas celulares: MDCK y células Vero. Se determinó la citotoxicidad del extracto y se estimó que el valor de CC50 para la línea celular MDCK resulta de (400 ± 59 mg/mL y en las células Vero de (137,3 ± 23 mg/mL. A concentraciones no citotóxicas el extracto no indujo la fragmentación del ADN. El efecto del extracto sobre las células infectadas con los virus influenza A/ Japan/10/99(H3N2, influenza B/Beijing/88 fue evaluado mediante la técnica del MTT y el análisis de la fragmentación del ADN, técnicas usadas para identificar el proceso de muerte apoptótica. El proceso de apoptosis fue inhibido por el extracto a todas las concentraciones y tiempos ensayados. A partir de los resultados, se infiere la existencia de mecanismos comunes de inducción de la apoptosis por estos virus que son interferidos por el extracto natural ensayado.

  17. Enzima convertidora frente a quimasa mastocitaria en la infiltración leucocitaria inducida por angiotensina-I : papel de fractalquina en la inflamación vascular causada por humo de tabaco

    OpenAIRE

    Company de la Calle, Chantal

    2011-01-01

    En la presente Tesis Doctoral se han abordado dos objetivos: el estudio de la contribución de la enzima convertidora (ECA) frente a la quimasa mastocitaria en la acumulación leucocitaria inducida por la síntesis endógena de Ang-II in vivo, y el estudio del papel de fractalquina (FRK) en la inflamación sistémica inducida por el extracto de humo de tabaco (EHT). La enzima convertidora de la angiotensina (ECA) es la principal enzima implicada en la formación de Ang-II a partir de Ang-I. Sin...

  18. 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

  19. 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 hiperlip...

  20. Arteriopatía periférica crónica inducida por cocaína

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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.

  1. 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.

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

    OpenAIRE

    E Rivadeneyra-Domínguez; M. Saavedra; JF Rodríguez-Landa

    2009-01-01

    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 S...

  3. 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.

  4. 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.

  5. 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

    2013-01-01

    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...

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Efecto del OLEOZON® frente a lesiones gástricas inducidas por indometacina en ratas (Effect of OLEOZON® on gastric lesions induced by indomethacin in rats

    Directory of Open Access Journals (Sweden)

    González Alvarez Ricardo

    2007-03-01

    Full Text Available El aceite de girasol ozonizado es un fármaco registrado en Cuba para el tratamiento de la giardiasis con el nombre de OLEOZON®; los ensayos clínicos realizados han demostrado que posee efectividad terapéutica comparable con un fármaco de referencia, Ornidazol. Elobjetivo del presente estudio fue determinar si el Oleozon es capaz de ejercer efecto protector contra las lesiones gástricas inducidas por la indometacina en las ratas. Estos animales fueron divididos para dos diferentes diseños experimentales con 6 grupos cada uno. En el primer experimento las ratas fueron pretratadas oralmente conOleozon (4, 12 y 24 mg/kg y 4 horas después con indometacina. En el segundo experimento las lesiones gástricas fueron inducidas por indometacina y 4 horas después tratadas con Oleozon en el mismo rango de dosis que en el anterior experimento. Las lesiones gástricas fueron evaluadas determinando el índice de ulceración. La Cimetidina fue utilizada como fármaco antiulceroso de referencia. Los resultadosdemostraron que el pretratamiento con Oleozon no impidió el daño gástrico inducido por la indometacina y no tuvo efecto citoprotector. En contraste con esto el tratamiento con Oleozon indujo reversión delas lesiones gástricas inducidas previamente por la indometacina demostrando su efecto anti-ulcerogénico en este modelo. Ozonized sunflower oil is a drug registered in Cuba for the treatment of giardiasis and it is commercially available with the name ofOleozon. The clinical trials have demonstrated that Oleozon possess therapeutic effectiveness comparable with a reference drug, Ornidazol. The aim of the present study was to determine whether Oleozon is able to exert protective effects against gastric lesionsinduced by indomethacin in rats. The animals were divided for two different experimental designs with six groups each one. In the firstexperiment the rats were pretreated with Oleozon (4, 12 y 24 mg/kg and four hours thereafter with

  14. Efecto de Gentianella alborosea en esteatosis hepática no alcohólica inducida por dieta hiperlipídica en ratas holtzman hembras

    Directory of Open Access Journals (Sweden)

    L Ugaz-Soto

    2013-01-01

    Full Text Available 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 hiperlipídica, dosis 1 (35 mg/kg y dosis 2 (70 mg/kg. Se indujo EHNA con dieta hiperlipídica (Carbohidratos: 26%, Lípidos: 59% y Proteínas: 15% Calorías durante un período de 21 días, ad libitum. Luego, se administró el extracto acuoso de Gentianella alborosea por 4 días. Finalmente, se extrajeron los hígados para evaluar las alteraciones histopatológicas del parénquima hepático. Principales medidas de resultados: Se realizó el conteo microscópico de hepatocitos afectados con macrovacuolas, y los resultados fueron comparados mediante las pruebas de ANOVA (p<0,05 y HSD de Tukey (p<0,05. Resultados: Se encontró diferencias significativas (p<0.05 en el porcentaje de hepatocitos afectados entre los grupos dosis 1 (3.25 ± 2.27 y el control positivo (7.50 ± 3.76. Además, no se encontró diferencia significativa entre los grupos dosis 1 y dosis 2. Conclusiones: No se pudo determinar el efecto de Gentianella alborosea sobre la esteatosis hepática no alcohólica inducida por dieta hiperlipídica en ratas Holtzman hembra, por lo que se recomiendan estudios posteriores.

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

    Directory of Open Access Journals (Sweden)

    L. Ugaz-Soto

    2012-01-01

    Full Text Available 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 hiperlipídica, dosis 1 (35 mg/kg y dosis 2 (70 mg/kg. Se indujo EHNA con dieta hiperlipídica (Carbohidratos: 26%, Lípidos: 59% y Proteínas: 15% Calorías durante un período de 21 días, ad libitum. Luego, se administró el extracto acuoso de Gentianella alborosea por 4 días. Finalmente, se extrajeron los hígados para evaluar las alteraciones histopatológicas del parénquima hepático. Principales medidas de resultados: Se realizó el conteo microscópico de hepatocitos afectados con macrovacuolas, y los resultados fueron comparados mediante las pruebas de ANOVA (p<0,05 y HSD de Tukey (p<0,05. Resultados: Se encontró diferencias significativas (p<0.05 en el porcentaje de hepatocitos afectados entre los grupos dosis 1 (3.25 ± 2.27 y el control positivo (7.50 ± 3.76. Además, no se encontró diferencia significativa entre los grupos dosis 1 y dosis 2. Conclusiones: No se pudo determinar el efecto de Gentianella alborosea sobre la esteatosis hepática no alcohólica inducida por dieta hiperlipídica en ratas Holtzman hembra, por lo que se recomiendan estudios posteriores.

  16. Estrés oxidativo hepático en ratas con insulinorresistencia inducida por dieta rica en fructosa y su remisión por administración de ácido α lipoico

    OpenAIRE

    Castro, María Cecilia

    2012-01-01

    La administración de una DRF a ratas normales induce rápidamente alteraciones metabólicas (hipertrigliceridemia y TGA), endocrinas (IR, hiperinsulinemia e hiperleptinemia), cambios en el metabolismo hepático de glúcidos y lípidos e incremento de la producción de ROS (Alzamendi y col., 2009; Castro y col., 2011; Francini y col., 2009; 2010; Rebolledo y col., 2008). Nuestra hipótesis de trabajo es que el hígado afronta inicialmente la sobrecarga metabólica inducida por una DRF, la cual genera u...

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

    Directory of Open Access Journals (Sweden)

    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.

  18. El estrés oxidativo: detonante fisiopatológico en la cardiomiopatía dilatada inducida por doxorrubicina

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    Yanet Hernández Matos

    2011-10-01

    Full Text Available La cardiomiopatía dilatada inducida por doxorrubicina constituye uno de los principales efectos indeseables del tratamiento de pacientes con tumores malignos. El estrés oxidativo constituye uno de los mecanismos fisiopatológicos que desempeñan un papel fundamental en la instauración de la enfermedad causada por este antibiótico del grupo de las antraciclinas. La comprensión de estos mecanismos fisiopatológicos resulta de vital importancia para llevar a cabo estrategias de intervención farmacológica y nutricional para contribuir a palear los efectos nocivos de este antineoplásico. En el presente trabajo se realizó una actualización bibliográfica sobre el tema y se proponen ideas que pueden ser útiles para la comunidad científica que está enfrascada en el tratamiento de esta enfermedad crónica, y que se propone mejorar la calidad de vida de los pacientes que la padecen.

  19. Anisotrop??a s??smica acimutal inducida por la presencia de fractura : aplicaci??n sobre datos s??smicos adquiridos en el anticlinal de Suesca, Cundinamarca, Colombia

    OpenAIRE

    Aguilera Bustos, Joaqu??n Pablo

    2010-01-01

    Actualmente, uno de los intereses en la exploraci??n de nuevos yacimientos est?? enfocado al entendimiento de zonas complejas, dentro de las cuales se encuentra ??reas que presentan rocas fracturadas. Este tipo de rocas pueden presentar anisotropa acimutal inducida, en la mayora de los casos, por la alineaci??n preferencial de los sistemas de fracturas (Hudson, 1980, 1981; Schoenberg et al, 1995). Uno de los objetivos de este trabajo es aportar al entendimiento de este fen??meno, donde alguno...

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

    Directory of Open Access Journals (Sweden)

    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.

  1. Efecto de los compuestos fenólicos apigenina, catequinas del cacao,ácido rosmarínico y eriocitrina sobre la carcinogénesis oral inducida por DMBA en hámsters

    OpenAIRE

    Baldasquín Cáceres, Beatriz

    2012-01-01

    El carcinoma oral de células escamosas es el cáncer más frecuente de cabeza y cuello, y está caracterizado por una baja tasa de supervivencia y mal pronóstico. La quimioprevención de esta enfermedad mediante extractos naturales constituye un importante campo de investigación en la actualidad. En el presente estudio hemos aplicado el modelo de carcinogénesis oral inducida por 7,12-dimetil-1,2-benzatraceno (DMBA) sobre 61 hámster sirios (Mesocricatus auratus) para estudiar el efecto quimiopre...

  2. Estructuras sedimentarias inducidas por actividad microbiana (ESIAM en la planicie de marea de Puerto Rosales, estuario de Bahía Blanca

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    Constanza N Bournod

    2014-09-01

    Full Text Available El estudio de matas microbianas en ambientes marinos costeros silicoclásticos actuales constituye una importante fuente de información para el análisis de análogos fósiles. En el estuario de Bahía Blanca se estudiaron planicies de marea cubiertas por matas desde un enfoque geobiológico, con el objetivo de identificar y describir estructuras inducidas por actividad microbiana (ESIAM, y distinguir rasgos presentes en los sistemas actuales que permitan reconocer estas comunidades de microorganismos en depósitos fósiles. Se realizaron muestreos biológicos y sedimentológicos, y se implementaron técnicas de microscopía óptica y electrónica para la determinación de microorganismos y la identificación de texturas características y minerales autigénicos. Las matas microbianas resultaron estar dominadas por cianobacterias y, en menor proporción, diatomeas; microorganismos que generan sustancias exopoliméricas que bioestabilizan la superficie sedimentaria. Se reconocieron texturas típicas de matas epibentónicas, tales como granos orientados y granos pequeños unidos por la mata, pirita framboidal y ceolitas. En la zona intermareal-supramareal se identificaron domos de gas, fábrica porosa esponjosa y superficies tipo colador. Además se observaron grietas de contracción, dobleces, fragmentos de mata, depresiones y remanentes erosivos, pliegues y arrugas, así como también ondulitas multidireccionales. Las estructuras halladas están relacionadas con condiciones de calma/latencia, exposición prolongada (desecación y eventos de tormenta con alta energía erosiva sobre la planicie (olas y corrientes fuertes. En este sentido, las ESIAM resultan importantes indicadoras de condiciones ambientales particulares que presentan un elevado potencial de preservación. Su reconocimiento en el registro fósil, a través de rasgos macro y microscópicos, permiten refinar las interpretaciones paleoambientales en sucesiones marino-costeras.

  3. 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.

  4. Mecanismo de la apoptosis inducida por el inhibidor de quinasas sorafenib en células de mieloma humano

    OpenAIRE

    Ramírez Labrada, Ariel Gaspar; Naval Iraberri, Javier; Marzo Rubio, María Isabel

    2013-01-01

    El mieloma múltiple (MM) es la segunda neoplasia hematológica más frecuente, después del linfoma no Hodgkin y constituye, aproximadamente, el 10% de todas las neoplasias hematológicas, y el 1% de todos los cánceres y causa el 2% de las muertes por cáncer. El sorafenib es un inhibidor de múltiples quinasas diseñado originalmente como inhibidor de la vía de las MAPK. Debido que la actividad de ERK es esencial para la proliferación de las células de mieloma múltiple mediada por la IL-6, se anal...

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

    OpenAIRE

    Omar Vesga; María Agudelo; Carlos Rodriguez; Andrés Zuluaga; Beatriz Salazar

    2004-01-01

    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.

     

     

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

    OpenAIRE

    Javier F. Bonilla; Fernando Palomino

    2008-01-01

    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 seden...

  7. 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.

     

     

  8. Papel de la autofagia en la lesión pulmonar inducida por ventilación

    OpenAIRE

    López Alonso, Inés

    2012-01-01

    La autofagia en condiciones basales es un proceso imprescindible durante el desarrollo, pero también forma parte de la respuesta al estrés. En este sentido, inductores bien conocidos de la autofagia son por ejemplo el ayuno o el lipopolisacárido bacteriano (LPS). Nuestra hipótesis es que la ventilación mecánica, que como terapia de soporte vital se utiliza rutinariamente en pacientes críticos, puede activar este proceso y disparar a su vez una respuesta inflamatoria a través de la activación ...

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

    OpenAIRE

    Idioleidys Alvarez; Ofelia Sam; Inés Reynaldo

    2005-01-01

    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 ap...

  10. 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.

  11. 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.

     

     

  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. Hemorragia pulmonar inducida por el ejercicio en el caballo: una revisión Exercise-induced pulmonary hemorrhage in horses: a review

    Directory of Open Access Journals (Sweden)

    G. MORAN

    2003-12-01

    Full Text Available La Hemorragia Pulmonar Inducida por Ejercicio (HPIE es una de las patologías respiratorias más importantes del equino de deporte ya que afecta directamente el rendimiento deportivo. Su importancia radica, que entre un 42 a un 85% de los equinos sometidos a un esfuerzo sufren esta condición. La hipótesis más aceptada en cuanto al origen y mecanismo de HPIE es la ruptura de capilares pulmonares durante el ejercicio. Esto resulta de una hipertensión vascular en combinación con una gran presión negativa intrapleural, lo que genera un aumento de la presión capilar pulmonar llevando a la hemorragia. La endoscopía del tracto respiratorio es de gran utilidad para la detección de HPIE, ya que se observa directamente la presencia de sangre. A pesar de que esta patología se describió hace varios siglos, aún no se ha establecido el origen de la enfermedad, ni tampoco un tratamiento preventivo y curativo que la solucione en forma definitiva. La furosamida es la droga de elección en el tratamiento y prevención de HPIE, ya que aumenta el volumen urinario y de este modo disminuye el volumen sanguíneo, aliviándose la función sistólica del ventrículo derecho, con disminución de las altas presiones arteriopulmonares. La presente revisión pretende dar una visión actualizada sobre los factores de presentación de la patología, como así también signos clínicos, posibles causas, fisiopatología, diagnóstico y tratamientoExercise-induced pulmonary hemorrhage (EIPH is as mayor cause of poor performance in the equine athlete. It is an important cause of exercise intolerance and results from strenuous exercise and pathophysiological changes in the equine lung and possibly in the airways. Endoscopic surveys of the respiratory tract of horses after competitive events have shown that many horses experience EIPH, but only a relativity small percentage shows blood at the nostrils. The reported incidence of EIPH in different breeds varies between 40

  16. Efectos de la terapia combinada del D-004 y el Finasteride sobre la hiperplasia de próstata inducida por testosterona en ratas

    OpenAIRE

    Molina, Vivian; Arruzazabala, María de Lourdes; Carvajal, Daysi; Más, Rosa

    2007-01-01

    La hiperplasia prostática benigna (HPB) es la causa principal de los síntomas molestos del tracto bajo urinario en el hombre adulto. El finasteride, un inhibidor de la enzima 5α-reductasa prostática es un agente terapéutico ampliamente utilizado en la HPB. El D-004, un extracto lipídico obtenido del fruto de Roystonea regia, previene la hiperplasia de próstata inducida con testosterona (T) pero no con dihidrotestosterona (DHT) en roedores. Este estudio fue realizado con el objetivo de ev...

  17. 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

  18. 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.

  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

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    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. 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

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    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

  2. 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

    2013-01-01

    [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...

  3. 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

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    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.

  4. Relación entre el silenciamiento de RNA y la patogénesis inducida por un viroide con replicación nuclear

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    Martínez Arias, Germán Eugenio

    2011-01-01

    Interés del estudio: Los viroides son patógenos exclusivos de plantas que infectan un gran número de especies de interés agronómico. Sin capacidad descrita para codificar proteínas, todas las fases de su ciclo vital son estrictamente dependientes de su interacción con factores del huésped. Históricamente se ha asumido que la patogénesis es consecuencia de la competencia huésped-patógeno por factores celulares implicados en el ciclo vital del viroide. En los últimos años se ha propuesto que...

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

    OpenAIRE

    Paternain, L. (Laura); Campion, J; J. A. Martinez

    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...

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

    OpenAIRE

    Miguel E. Pinto; Claudia Banda; Carlos Seas

    2012-01-01

    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...

  7. Ca2+-ATPasa y Muerte Celular Inducida por Ca2+ en células Cardíacas H9c2

    OpenAIRE

    Lax Pérez, Antonio Manuel

    2009-01-01

    La Ca2+-ATPasa de RS puede hidrolizar ATP a través de una ruta alternativa en la que solo intervienen conformaciones de la proteína que no unen Ca2+. El mecanismo molecular de esta actividad hidrolítica implica un cambio conformacional inducido por ATP que produce aproximaciones de los dominios citosólicos. El uso de indicadores fluorescentes y compuestos que movilizan Ca2+ permite caracterizar flujos y depósitos intracelulares de Ca2+ que están implicados en la generación de señales intracel...

  8. 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...

  9. 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

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    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

  10. 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

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    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

  11. 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.

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

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    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.

  13. 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

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    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

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

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    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.

  15. 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.

  16. 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

  17. Susceptibilidad a grietas inducidas por hidrógeno en ambiente corrosivo de H2S de juntas soldadas de acero API 5L-X80

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    Hilton, J.

    2009-08-01

    Full Text Available The susceptibility to hydrogen-induced cracking in H2S environment of welded API X80 steel was studied. The flux cored arc welding (FCAW process was employed with E71-T1 and E71-T8K6 wires. The welding parameters were kept constant, but the samples were welded using different preheat temperatures (room temperature and 100ºC. The gapped bead-on-plate (G-BOP test was used. The specimens of modified G-BOP tests were exposed to an environment saturated in H2S, as recommended by the NACE TM0284 standard. The weld beads were characterized by optical microscopy and the level of residual hydrogen in the samples was measured. The fracture surface areas of hydrogen-induced cracking were calculated and the fracture mode was discussed. It was found that the preheating temperature of 100ºC was enough to avoid cracking, even in the presence of H2S. It was also found that the E71- T8K6 wire was more susceptible to cracking, and the typical mixed-mode fracture was predominant in all samples.

    En este trabajo fue realizado un estudio sobre la susceptibilidad al agrietamiento inducido por el hidrógeno de uniones soldadas de aceros API –X80, expuestas a un ambiente saturado en ácido sulfhídrico (H2S. Fue empleado el ensayo G-BOP modificado. El proceso de alambre tubular, con dos metales de aporte, E71-T1 y E71-T8K6, fue usado, manteniendo constante los parámetros del proceso de soldadura. Las probetas fueron soldadas a temperatura ambiente y también tras precalentamiento a 100ºC. Los bloques soldados del ensayo G-BOP modificado fueron expuestos a un ambiente saturado en H2S, según recomienda la norma NACE TM0284. Los cordones de soldadura fueron caracterizados microestructuralmente y realizados análisis de hidrógeno residual en las probetas. Se observaron y calcularon las áreas de las superficies de fractura de las grietas inducidas por el hidrógeno y se analizaron

  18. PROFILAXIS DE LA NEFROPATÍA INDUCIDA POR CONTRASTE EN PACIENTES DE ALTO RIESGO CON SÍNDROME CORONARIO AGUDO SIN ELEVACIÓN DEL SEGMENTO ST / Prophylaxis of contrast-induced nephropathy in high risk patients with non-ST-segment elevation acute coronary syndrome

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    Pilar Portero Pérez

    2012-07-01

    Full Text Available ResumenIntroducción y objetivos: La eficacia de la administración conjunta de suero salino isotónico y N-acetilcisteína presenta resultados dispares en la prevención de la nefropatía por contraste yodado. Nuestro objetivo fue valorar la posible eficacia de esta estrategia combinada en pacientes con alto riesgo de desarrollar nefropatía inducida por contraste, ingresados y sometidos a intervencionismo coronario percutáneo por síndrome coronario agudo sin elevación del segmento ST en nuestro centro. Método: Se aplicó esta estrategia en los pacientes referidos, con al menos un factor de alto riesgo para desarrollar la nefropatía inducida por contraste: mayores de 80 años, diabetes mellitus, creatinina basal mayor de 1,5 mg/dl o alto volumen de contraste (mayor de 400 ml. El protocolo se aplicó durante 12 meses (pacientes que recibieron el protocolo de prevención y se comparó con similares pacientes en los 12 meses previos que no recibieron profilaxis. Resultados: Un total de 30 pacientes (24 % desarrollaron nefropatía inducida por contraste. El porcentaje fue significativamente mayor en el grupo que no recibió profilaxis: 35,9 % vs. 11,5 % (p = 0.003. Conclusiones: La combinación de N-acetilcisteína por vía oral e hidratación parenteral en pacientes de alto riesgo, con síndrome coronario agudo sin elevación de ST, podría ser beneficiosa para evitar la aparición de la nefropatía inducida por contraste. /Abstract Introduction and Objectives: The effectiveness of the administration of isotonic saline solution and N-acetylcysteine shows different results in the prevention of iodine contrast nephropathy. Our objective was to assess the potential effectiveness of this combined strategy in patients at high risk for contrast-induced nephropathy, who were admitted in our center for percutaneous coronary intervention due to non-ST-segment elevation acute coronary syndrome. Method: This strategy was applied in the patients

  19. 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

  20. 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; Pinto, Miguel E.

    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...

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. Aplicación de las células madre inducidas al estudio de las enfermedades neurodegenerativas

    OpenAIRE

    Martín Muñiz, Marta

    2013-01-01

    La atrofia muscular espinal es una enfermedad causada por una mutación en el gen SMN1 que conduce a la pérdida de neuronas motoras. Mediante la utilización de células inducidas pluripotenciales se estudiará el papel neuroprotector del GDNF sobre las neuronas motorasen pacientes con esta enfermedad.

  6. 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

  7. 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

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    Zalacain, M. (Marta); Sierrasesúmaga, L.; Patiño, A. (Ana)

    2005-01-01

    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 cromosómic...

  8. 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

  9. Producción de gas de síntesis a partir de pirólisis de residuos inducida por microondas para su utilización en la obtención de bioplásticos

    OpenAIRE

    Beneroso Vallejo, Daniel

    2016-01-01

    En la Unión Europea se generan anualmente hasta 3000 millones de toneladas de residuos. Entre ellos, los residuos sólidos de origen orgánico tienen un gran potencial para satisfacer parcialmente la producción de productos químicos, reduciéndose el impacto medioambiental e incrementándose la sostenibilidad de los procesos. Sin embargo, este tipo de residuos son complejos debido a su alta heterogeneidad, por lo que se requieren nuevos procesos de conversión que permitan reducir su complejidad e...

  10. Dabigatran como posibilidad terapéutica en el síndrome de trombocitopenia inducida por heparina tipo II Dabigatran as a therapeutic possibility in heparin-induced thrombocytopenia type II

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    F.J. Anniccherico

    2012-12-01

    Full Text Available El síndrome de trombocitopenia inducido por heparina (HIT con una incidencia del 0,2-0,5 % en pacientes expuestos a heparina durante más de 4 días, es producido por una alteración inmune con formación de anticuerpos frente al complejo heparina-factor 4 plaquetario, que presenta un amplio espectro de manifestaciones clínicas: siendo la trombocitopenia, los fenómenos trombóticos arteriales/venosos y la necrosis cutánea los más frecuentes. Hasta el momento actual, lepirudina, recientemente suspendida y argatroban (inhibidores directos de la trombina son los fármacos aprobados y habitualmente usados en el tratamiento, suministrados de forma parenteral. El dabigatran, un nuevo fármaco anticoagulante, inhibidor directo y reversible de la trombina teóricamente podría ser un fármaco empleado en el tratamiento del HIT. Según la bibliografía consultada presentamos el primer caso de HIT tratada con dabigatran en la literatura médica.The syndrome of heparin-induced thrombocytopenia (HIT, with an incidence of 0.2-0.5% in patients exposed to heparin for more than 4 days, is produced by an immune alteration with the formation of antibodies against the heparin platelet factor 4 complex. It presents a wide spectrum of clinical manifestations, the most frequent of which are thrombocytopenia, thrombotic arterial-venous phenomena, and cutaneous necrosis. Up to the present, lepiridin, recently suspended, and argatroban (direct thrombin inhibitors have been the approved medicines normally used in treatment, administered in parenteral form. Dabigatran, a new anticoagulant medicine that is a direct and reversible thrombin inhibitor, could theoretically be a medicine employed in treating HIT. According to the bibliography consulted we are presenting the first case of HIT treated with dabigatran in the medical literature.

  11. Prevention, Diagnosis and Treatment of Chemotherapy-Induced Cardiotoxicity: what Are we Doing about it? Prevención, diagnóstico y tratamiento de la cardiotoxicidad inducida por quimioterapia: ¿qué estamos haciendo?

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    Lázaro de la Cruz Avilés

    2012-11-01

    Full Text Available Heart disease and malignant tumors are the two leading causes of death in Cuba, with mortality rates of 197,5 and 193,6 per 100 000, respectively, in 2011. In Cienfuegos, malignant tumors were the leading cause of death with a rate of 115,2 followed by heart disease with 102,6 per 100 000 inhabitants. The improvements in the detection and treatment of cancer have led to a new cohort of patients achieving such a long survival that cardiac complications may appear. Unfortunately, the wide knowledge on biochemical pathways involved in cancer targeted therapy has not been accompanied by a parallel understanding of cardiac consequences of their modulation.Las enfermedades del corazón y los tumores malignos constituyen las dos primeras causas de muerte en Cuba, con tasas de mortalidad de 197,5 y 193,6 por 100 000 habitantes, respectivamente, en el año 2011. En Cienfuegos los tumores malignos fueron la primera causa de muerte con una tasa de 115,2 seguida de las enfermedades del corazón con 102,6 por 100 000 habitantes. Las mejoras alcanzadas en la detección y el tratamiento del cáncer han dado origen a una nueva cohorte de pacientes que alcanzan una supervivencia suficiente para que puedan aparecer complicaciones cardíacas derivadas del tratamiento. Lamentablemente, el abundante conocimiento sobre las vías bioquímicas involucradas en el tratamiento dirigido del cáncer no se ha visto acompañado de un conocimiento paralelo de las consecuencias cardíacas de su modulación.

  12. 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

  13. 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

    Directory of Open Access Journals (Sweden)

    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

  14. 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.

  15. 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

    Directory of Open Access Journals (Sweden)

    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

  16. 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

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    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

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

    OpenAIRE

    Musso CG; Macías Núñez JF; Imperiali N; Algranati L

    2005-01-01

    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 ...

  18. 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)

  19. 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

  20. 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

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

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    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

  2. 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

  3. 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.

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

    OpenAIRE

    Imir R Vázquez; Antonio F Aguilera; Lilia A Prado-Barragán; Cristóbal N. Aguilar

    2008-01-01

    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...

  5. Motor Axon Pathfinding

    OpenAIRE

    Bonanomi, Dario; Pfaff, Samuel L

    2010-01-01

    Motor neurons are functionally related, but represent a diverse collection of cells that show strict preferences for specific axon pathways during embryonic development. In this article, we describe the ligands and receptors that guide motor axons as they extend toward their peripheral muscle targets. Motor neurons share similar guidance molecules with many other neuronal types, thus one challenge in the field of axon guidance has been to understand how the vast complexity of brain connection...

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

    OpenAIRE

    D.F. Arencibia; Rosario, L.A.; Y.E Suárez; Delgado, L.

    2011-01-01

    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 in...

  7. Determinants of axonal regeneration

    OpenAIRE

    Frisén, J

    1997-01-01

    Axons often regrow to their targets and lost functions may be restored after an injury in the peripheral nervous system. In contrast, axonal regeneration is generally very limited after injuries in the central nervous system, and functional impairment is usually permanent. The regenerative capacity depends on intrinsic neuronal factors as weil as the interaction of neurons with other cells. Glial cells may, in different situations, either support or inhibit axo...

  8. Mecanismos moleculares implicados en las alteraciones metabólicas inducidas por la suplementación subcrónica de fructosa líquida: estrés de retículo, autofagia y resistencia a la insulina

    OpenAIRE

    Baena Muñoz, Miguel

    2015-01-01

    En las últimas décadas se ha observado un aumento muy notable de la prevalencia de enfermedades metabólicas como la obesidad, el síndrome metabólico y la resistencia a la insulina. Por ejemplo, en Estados Unidos, casi tres cuartas partes de la población adulta presentan sobrepeso u obesidad. De éstos, casi una tercera parte padecen el síndrome metabólico. En España, un estudio de la Sociedad Española para el Estudio de la Obesidad (SEEDO) realizado en el año 2000, muestra una prevalencia de l...

  9. 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

    OpenAIRE

    CA Henríquez; LM Mieres; HA Bustamante; Herzberg; CE Campillo; MP Cabrera; MA Gómez

    2011-01-01

    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 admi...

  10. Estudio prospectivo randomizado doble ciego para valorar la seguridad y eficacia de palonosetrón más aprepitant versus granisetrón en la profilaxis de la emesis inducida por quimioterapia en el transplante de precursores hemotopoyéticos

    OpenAIRE

    Tenorio Núñez, María Concepción

    2013-01-01

    El estudio de las náuseas y vómitos inducidos por quimioterapia (NVIQ) en el acondicionamiento de los trasplantes de precursores hematopoyéticos (TPH) es escaso. Las peculiaridades de este tipo de procedimiento requieren una consideración especial y diferente a la administración de quimioterapia en el contexto del tratamiento de una neoplasia puesto que conlleva un peor control de las NVIQ. El objetivo principal de la tesis consistió en evaluar la eficacia en términos de respuesta completa (R...

  11. 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.

  12. 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

  13. 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

  14. 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

  15. causada por Fusarium moniliforme

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    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. Estudio de la Cinética de Precipitación Inducida Mediante la Determinación de los Diagramas Precipitación-Tiempo-Temperatura (PTT) en Aceros Microaleados

    OpenAIRE

    Medina, Sebastián F.

    1995-01-01

    [ES]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 ...

  17. Brain gangliosides in axon-myelin stability and axon regeneration

    OpenAIRE

    Schnaar, Ronald L.

    2009-01-01

    Gangliosides, sialic acid-bearing glycosphingolipids, are expressed at high abundance and complexity in the brain. Altered ganglioside expression results in neural disorders, including seizures and axon degeneration. Brain gangliosides function, in part, by interacting with a ganglioside-binding lectin, myelin-associated glycoprotein (MAG). MAG, on the innermost wrap of the myelin sheath, binds to gangliosides GD1a and GT1b on axons. MAG-ganglioside binding ensures optimal axon-myelin cell-ce...

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

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    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.

  19. 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)

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

    OpenAIRE

    Luis S. Algranati L; Nora Imperiali; Hector Rivera; Juan F. Macías Núñez; Musso, Carlos G.

    2006-01-01

    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 solv...

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

    OpenAIRE

    Daniela Montes Berrueta; Sofía Dugarte-Da Silva; Nathaly Rojas Duque; Siham Salmen; Lisbeth Berrueta

    2012-01-01

    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 petun...

  2. 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.

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

    OpenAIRE

    J. Boldú; V. M. Eguía

    2005-01-01

    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 m...

  4. 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.

  5. Alergia en el humano inducida por la saliva de insectos de la familia culicidae

    OpenAIRE

    Moncada Álvarez, Ligia Inés; Salazar Terreros, Myriam Janeth; López Páez, Myriam Consuelo

    2011-01-01

    Se hace una revisión de las moléculas que inoculan los insectos de la familia Culicidae al momento de la picadura y los mecanismos que muestran sus hospederos para contrarrestarlos y cómo algunas de esas moléculas, especialmente las enzimas se convierten en alérgenos que inducen una respuesta de amplio espectro, que va desde una pápula al momento de la picadura hasta una reacción anafiláctica. De la misma manera se analizan las posibilidades de diagnóstico con moléculas silvestres y antígenos...

  6. Efecto mediador del optimismo en los sesgos cognitivos provocados por emociones inducidas

    OpenAIRE

    Beneyto Molina, Vicent Blai

    2011-01-01

    De acuerdo con la teoría "broaden and build" de las emociones positivas, determinadas emociones positivas tienen la capacidad de ampliar momentáneamente los repertorios de pensamientoacción, contribuyendo a construir unos recursos personales resistentes, alcanzando desde los recursos físicos e intelectuales a los sociales o psicológicos. Una de las implicaciones del modelo original de la teoría, es el hecho de que las emociones positivas sirven para deshacer los efectos cardiovasculares produ...

  7. 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.

  8. Estudio de reacciones cut??neas inducidas por la vitamina K

    OpenAIRE

    Mart??nez, Carmen; Nogueras, Paloma; Valenzuela, Ignacio; Garc??a, Eliseo; Tercedor, Jes??s

    2011-01-01

    La patolog??a iatrog??nica constituye en el momento actual una de las facetas m??s importantes de la dermatolog??a. La vitamina K es un principio activo que se ha asociado a m??ltiples cuadros cut??neos adversos, que aunque son excepcionales, se han registrado repetidamente en la literatura. Adoptan un aspecto cl??nico, una morfolog??a patol??gica y un curso pron??stico caracter??stico. En el presente art??culo se realiza una revisi??n informatizada y manual desde los primeros cas...

  9. 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)

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

    Directory of Open Access Journals (Sweden)

    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. 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.

  12. 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.

  13. Local translation and directional steering in axons

    OpenAIRE

    Lin, Andrew C; Holt, Christine E.

    2007-01-01

    The assembly of functional neural circuits in the developing brain requires neurons to extend axons to the correct targets. This in turn requires the navigating tips of axons to respond appropriately to guidance cues present along the axonal pathway, despite being cellular ‘outposts' far from the soma. Work over the past few years has demonstrated a critical role for local translation within the axon in this process in vitro, making axon guidance another process that requires spatially locali...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Axon density and axon orientation dispersion in children born preterm

    NARCIS (Netherlands)

    Kelly, Claire E.; Thompson, Deanne K.; Chen, Jian; Leemans, Alexander; Adamson, Christopher L.; Inder, Terrie E.; Cheong, Jeanie L Y; Doyle, Lex W.; Anderson, Peter J.

    2016-01-01

    Background Very preterm birth (VPT, <32 weeks' gestation) is associated with altered white matter fractional anisotropy (FA), the biological basis of which is uncertain but may relate to changes in axon density and/or dispersion, which can be measured using Neurite Orientation Dispersion and Density

  17. Outsourcing CREB translation to axons to survive

    OpenAIRE

    Lin, Andrew C; Holt, Christine E.

    2008-01-01

    Nerve growth factor induces sensory neuron survival via retrograde signalling from the axon to the cell body. Local translation of the transcription factor CREB in the axon, followed by its transport to the nucleus, is involved in this process.

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

    Directory of Open Access Journals (Sweden)

    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

  19. Axon damage and repair in multiple sclerosis.

    OpenAIRE

    Perry, V.H.; Anthony, D. C.

    1999-01-01

    It is well known that within long-standing multiple sclerosis (MS) lesions there is axonal loss but whether it is an early or late event has been more difficult to establish. The use of immunocytochemical methods that reveal axonal end-bulbs is a valuable approach to investigating acute axonal injury in human pathological material. The application of these techniques to multiple sclerosis tissue reveals evidence of axonal injury in acute lesions; the distribution of the end-bulbs in acute and...

  20. Axonal change in minor head injury.

    Science.gov (United States)

    Povlishock, J T; Becker, D P; Cheng, C L; Vaughan, G W

    1983-05-01

    Anterograde axonal transport of horseradish peroxidase (HRP) in selected cerebral and cerebellar efferents was studied in cats subjected to minor head injury. After trauma, the animals were allowed to survive from one to 24 hours, when they were perfused with aldehydes and processed for the light and electron microscopic visualization of the peroxidase reaction product. By light microscopy, the brain injury elicited an initial intra-axonal peroxidase pooling. With longer post-traumatic survival, HRP pooling increased in size, demonstrated frequent lobulation, and ultimately formed large ball- or club-like swellings which suggested frank axonal separation from the distal axonal segment. Ultrastructural examination revealed that the initial intra-axonal peroxidase pooling was associated with organelle accumulation which occurred without any other form of axonal change or related parenchymal or vascular damage. This accumulation of organelles increased with time and was associated with conspicuous axonal swelling. Ultimately these organelle-laden swellings lost continuity with the distal axonal segment and the axonal swelling was either completely invested by a thin myelin sheath or protruded without myelin investment into the brain parenchyma. This study suggests that axonal change is a consistent feature of minor head injury. Since these axonal changes occurred without any evidence of focal parenchymal or vascular damage, minor brain injury may ultimately disrupt axons without physically shearing or tearing them. PMID:6188807

  1. 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.

  2. 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.

  3. Human intraretinal myelination: Axon diameters and axon/myelin thickness ratios

    Science.gov (United States)

    FitzGibbon, Thomas; Nestorovski, Zoran

    2013-01-01

    Purpose: Human intraretinal myelination of ganglion cell axons occurs in about 1% of the population. We examined myelin thickness and axon diameter in human retinal specimens containing myelinated retinal ganglion cell axons. Materials and Methods: Two eyes containing myelinated patches were prepared for electron microscopy. Two areas were examined in one retina and five in the second retina. Measurements were compared to normal retinal and optic nerve samples and the rabbit retina, which normally contains myelinated axons. Measurements were made using a graphics tablet. Results: Mean axon diameter of myelinated axons at all locations were significantly larger than unmyelinated axons (P ≤ 0.01). Myelinated axons within the patches were significantly larger than axons within the optic nerve (P < 0.01). The relationship between axon diameter/fiber diameter (the G-ratio) seen in the retinal sites differed from that in the nerve. G-ratios were higher and myelin thickness was positively correlated to axon diameter (P < 0.01) in the retina but negatively correlated to axon diameter in the nerve (P < 0.001). Conclusion: Intraretinally myelinated axons are larger than non-myelinated axons from the same population and suggests that glial cells can induce diameter changes in retinal axons that are not normally myelinated. This effect is more dramatic on intraretinal axons compared with the normal transition zone as axons enter the optic nerve and these changes are abnormal. Whether intraretinal myelin alters axonal conduction velocity or blocks axonal conduction remains to be clarified and these issues may have different clinical outcomes. PMID:24212308

  4. 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.

  5. 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. PMID:27594833

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

    OpenAIRE

    Torres Tordera, Eva María

    2009-01-01

    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...

  7. La administración de Carditrofina-1 mejora la colitis ulcerosa inducida por dextrano sulfato de sodio

    OpenAIRE

    Prieto Vicente, Vanessa

    2015-01-01

    [ES] La enfermedad inflamatoria intestinal crónica (EIIC) surge de la interacción entre las bacterias de la luz intestinal y la mucosa y comprende la colitis ulcerosa (CU), la enfermedad de Crohn (EC) y la colitis inclasificable (CI) . Aunque la etiopatogenia de la EIIC no ha sido claramente dilucidada, se atribuye a una compleja interacción entre factores genéticos, ambientales, microbianos y diversos factores inmunes que incluyen péptidos quimiotácticos y citocinas proinflamatorias. La dis...

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. Neurofilament spacing, phosphorylation, and axon diameter in regenerating and uninjured lamprey axons.

    Science.gov (United States)

    Pijak, D S; Hall, G F; Tenicki, P J; Boulos, A S; Lurie, D I; Selzer, M E

    1996-05-13

    It has been postulated that phosphorylation of the carboxy terminus sidearms of neurofilaments (NFs) increases axon diameter through repulsive electrostatic forces that increase sidearm extension and interfilament spacing. To evaluate this hypothesis, the relationships among NF phosphorylation, NF spacing, and axon diameter were examined in uninjured and spinal cord-transected larval sea lampreys (Petromyzon marinus). In untransected animals, axon diameters in the spinal cord varied from 0.5 to 50 microns. Antibodies specific for highly phosphorylated NFs labeled only large axons (> 10 microns), whereas antibodies for lightly phosphorylated NFs labeled medium-sized and small axons more darkly than large axons. For most axons in untransected animals, diameter was inversely related to NF packing density, but the interfilament distances of the largest axons were only 1.5 times those of the smallest axons. In addition, the lightly phosphorylated NFs of the small axons in the dorsal columns were widely spaced, suggesting that phosphorylation of NFs does not rigidly determine their spacing and that NF spacing does not rigidly determine axon diameter. Regenerating neurites of giant reticulospinal axons (GRAs) have diameters only 5-10% of those of their parent axons. If axon caliber is controlled by NF phosphorylation via mutual electrostatic repulsion, then NFs in the slender regenerating neurites should be lightly phosphorylated and densely packed (similar to NFs in uninjured small caliber axons), whereas NFs in the parent GRAs should be highly phosphorylated and loosely packed. However, although linear density of NFs (the number of NFs per micrometer) in these slender regenerating neurites was twice that in their parent axons, they were highly phosphorylated. Following sectioning of these same axons close to the cell body, axon-like neurites regenerated ectopically from dendritic tips. These ectopically regenerating neurites had NF linear densities 2.5 times those of

  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. PMID:27439954

  14. Neuronal Development: SAD Kinases Make Happy Axons

    OpenAIRE

    Xing, Lei; Newbern, Jason M.; Snider, William D

    2013-01-01

    The polarity proteins LKB1 and SAD-A/B are key regulators of axon specification in the developing cerebral cortex. Recent studies now show that this mechanism cannot be generalized to other classes of neurons: instead, SAD-A/B functions downstream of neurotrophin signaling in sensory neurons to mediate a later stage of axon development — arborization in the target field.

  15. Axon reflexes in human cold exposed fingers

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ducharme, M.B.

    2000-01-01

    Exposure of fingers to severe cold induces cold induced vasodilation (CIVD). The mechanism of CIVD is still debated. The original theory states that an axon reflex causes CIVD. To test this hypothesis, axon reflexes were evoked by electrical stimulation of the middle fingers of hands immersed in wat

  16. 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.

  17. 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. PMID:27439954

  18. The challenges of axon survival: introduction to the special issue on axonal degeneration.

    Science.gov (United States)

    Coleman, Michael P

    2013-08-01

    Early axon loss is a common feature of many neurodegenerative disorders. It renders neurons functionally inactive, or less active if axon branches are lost, in a manner that is often irreversible. In the CNS, there is no long-range axon regeneration and even peripheral nerve axons are unlikely to reinnervate their targets while the cause of the problem persists. In most disorders, axon degeneration precedes cell death so it is not simply a consequence of it, and it is now clear that axons have at least one degeneration mechanism that differs from that of the soma. It is important to understand these degeneration mechanisms and their contribution to axon loss in neurodegenerative disorders. In this way, it should become possible to prevent axon loss as well as cell death. This special edition considers the roles and mechanisms of axon degeneration in amyotrophic lateral sclerosis, Charcot-Marie-Tooth disease, hereditary spastic paraplegia, ischemic injury, traumatic brain injury, Alzheimer's disease, glaucoma, Huntington's disease and Parkinson's disease. Using examples from these and other disorders, this introduction considers some of the reasons for axon vulnerability. It also illustrates how molecular genetics and studies of Wallerian degeneration have contributed to our understanding of axon degeneration mechanisms. PMID:23769907

  19. 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.

  20. Dynamics of Mitochondrial Transport in Axons.

    Science.gov (United States)

    Niescier, Robert F; Kwak, Sang Kyu; Joo, Se Hun; Chang, Karen T; Min, Kyung-Tai

    2016-01-01

    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. PMID:27242435

  1. 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

  2. Evaluación del D-004 en el Ensayo de Ames por incorporación directa a placa

    OpenAIRE

    Gutiérrez Martínez, A.; Marrero Cofiño, G.; Gámez Menéndez, R.; I. Fernández; Curveco Sánchez, D.; H García Cambián

    2005-01-01

    El D-004 es un extracto lipídico obtenido del fruto de la palma real (Roystonea regia) (Arecaceae) que consiste en una mezcla reproducible de ácidos grasos, en la cual el ácido oleico, el laurico y el palmítico son los más abundantes. El tratamiento oral con D-004 inhibe significativamente la hiperplasia prostática (HP) inducida por testosterona en roedores. El objetivo de este trabajo fue investigar si el D-004 induce mutaciones génicas puntuales en el ensayo de Ames por incorporación direct...

  3. 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®.

  4. Genetics Home Reference: giant axonal neuropathy

    Science.gov (United States)

    ... in giant axonal neuropathy: new insights into disease mechanisms. Muscle Nerve. 2012 Aug;46(2):246-56. ... with a qualified healthcare professional . About Genetics Home Reference Site Map Contact Us Selection Criteria for Links ...

  5. 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

  6. Prolyl Isomerase Pin1 Regulates Axon Guidance by Stabilizing CRMP2A Selectively in Distal Axons

    Directory of Open Access Journals (Sweden)

    Martin Balastik

    2015-10-01

    Full Text Available Axon guidance relies on precise translation of extracellular signal gradients into local changes in cytoskeletal dynamics, but the molecular mechanisms regulating dose-dependent responses of growth cones are still poorly understood. Here, we show that during embryonic development in growing axons, a low level of Semaphorin3A stimulation is buffered by the prolyl isomerase Pin1. We demonstrate that Pin1 stabilizes CDK5-phosphorylated CRMP2A, the major isoform of CRMP2 in distal axons. Consequently, Pin1 knockdown or knockout reduces CRMP2A levels specifically in distal axons and inhibits axon growth, which can be fully rescued by Pin1 or CRMP2A expression. Moreover, Pin1 knockdown or knockout increases sensitivity to Sema3A-induced growth cone collapse in vitro and in vivo, leading to developmental abnormalities in axon guidance. These results identify an important isoform-specific function and regulation of CRMP2A in controlling axon growth and uncover Pin1-catalyzed prolyl isomerization as a regulatory mechanism in axon guidance.

  7. Efectos del D-004, extracto lipídico de los frutos de la Palma Real (Roystonea regia), sobre el granuloma inducido por algodón en ratas y sobre la lipoxigenasa presente en leucocitos polimorfonucleares (PMNs)

    OpenAIRE

    Menéndez, Roberto; Carvajal, Daysi; Mas, Rosa; Pérez, Yohanis; Molina, Vivian; Arruzazabala, María de Lourdes; González, Rosa María

    2006-01-01

    El D-004 es un extracto lipídico del fruto de la palma real (Roystonea regia, Arecaceae), en el cual los ácidos oleico, laurico y palmítico son los principales componentes. La administración oral inhibe significativamente la hiperplasia prostática inducida por testosterona en roedores. El objetivo del presente trabajo consistió en investigar los efectos anti-inflamatorios inducidos por el tratamiento oral con D-004 en el modelo de granuloma por algodón y sus efectos in vitro sobre la activida...

  8. Microfluidic device for unidirectional axon growth

    Science.gov (United States)

    Malishev, E.; Pimashkin, A.; Gladkov, A.; Pigareva, Y.; Bukatin, A.; Kazantsev, V.; Mukhina, I.; Dubina, M.

    2015-11-01

    In order to better understand the communication and connectivity development of neuron networks, we designed microfluidic devices with several chambers for growing dissociated neuronal cultures from mice fetal hippocampus (E18). The chambers were connected with microchannels providing unidirectional axonal growth between “Source” and “Target” neural sub-networks. Experiments were performed in a hippocampal cultures plated in a poly-dimethylsiloxane (PDMS) microfluidic chip, aligned with a 60 microelectrode array (MEA). Axonal growth through microchannels was observed with brightfield, phase-contrast and fluorescence microscopy, and after 7 days in vitro electrical activity was recorded. Visual inspection and spike propagation analysis showed the predominant axonal growth in microchannels in a direction from “Source” to “Target”.

  9. 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.

  10. 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.

  11. Functions of axon guidance molecules in synapse formation

    OpenAIRE

    Chen, Shih-Yu; Cheng, Hwai-Jong

    2009-01-01

    Axon guidance and synapse formation are important developmental events for establishing a functional neuronal circuitry. These two related cellular processes occur in a coordinated fashion but previous studies from multiple model organisms seemed to suggest that axon guidance and synapse formation are mediated by distinct molecular cues. Thus, axon guidance molecules are responsible for guiding the navigating axon toward its target area, while other adhesion or ligand-receptor molecules speci...

  12. Electrokinetic confinement of axonal growth for dynamically configurable neural networks.

    Science.gov (United States)

    Honegger, Thibault; Scott, Mark A; Yanik, Mehmet F; Voldman, Joel

    2013-02-21

    Axons in the developing nervous system are directed via guidance cues, whose expression varies both spatially and temporally, to create functional neural circuits. Existing methods to create patterns of neural connectivity in vitro use only static geometries, and are unable to dynamically alter the guidance cues imparted on the cells. We introduce the use of AC electrokinetics to dynamically control axonal growth in cultured rat hippocampal neurons. We find that the application of modest voltages at frequencies on the order of 10(5) Hz can cause developing axons to be stopped adjacent to the electrodes while axons away from the electric fields exhibit uninhibited growth. By switching electrodes on or off, we can reversibly inhibit or permit axon passage across the electrodes. Our models suggest that dielectrophoresis is the causative AC electrokinetic effect. We make use of our dynamic control over axon elongation to create an axon-diode via an axon-lock system that consists of a pair of electrode 'gates' that either permit or prevent axons from passing through. Finally, we developed a neural circuit consisting of three populations of neurons, separated by three axon-locks to demonstrate the assembly of a functional, engineered neural network. Action potential recordings demonstrate that the AC electrokinetic effect does not harm axons, and Ca(2+) imaging demonstrated the unidirectional nature of the synaptic connections. AC electrokinetic confinement of axonal growth has potential for creating configurable, directional neural networks. PMID:23314575

  13. 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.

  14. 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.

  15. Spatial temperature gradients guide axonal outgrowth

    Science.gov (United States)

    Black, Bryan; Vishwakarma, Vivek; Dhakal, Kamal; Bhattarai, Samik; Pradhan, Prabhakar; Jain, Ankur; Kim, Young-Tae; Mohanty, Samarendra

    2016-07-01

    Formation of neural networks during development and regeneration after injury depends on accuracy of axonal pathfinding, which is primarily believed to be influenced by chemical cues. Recently, there is growing evidence that physical cues can play crucial role in axonal guidance. However, detailed mechanism involved in such guidance cues is lacking. By using weakly-focused near-infrared continuous wave (CW) laser microbeam in the path of an advancing axon, we discovered that the beam acts as a repulsive guidance cue. Here, we report that this highly-effective at-a-distance guidance is the result of a temperature field produced by the near-infrared laser light absorption. Since light absorption by extracellular medium increases when the laser wavelength was red shifted, the threshold laser power for reliable guidance was significantly lower in the near-infrared as compared to the visible spectrum. The spatial temperature gradient caused by the near-infrared laser beam at-a-distance was found to activate temperature-sensitive membrane receptors, resulting in an influx of calcium. The repulsive guidance effect was significantly reduced when extracellular calcium was depleted or in the presence of TRPV1-antagonist. Further, direct heating using micro-heater confirmed that the axonal guidance is caused by shallow temperature-gradient, eliminating the role of any non-photothermal effects.

  16. Axonal PPARγ promotes neuronal regeneration after injury.

    Science.gov (United States)

    Lezana, Juan Pablo; Dagan, Shachar Y; Robinson, Ari; Goldstein, Ronald S; Fainzilber, Mike; Bronfman, Francisca C; Bronfman, Miguel

    2016-06-01

    PPARγ is a ligand-activated nuclear receptor best known for its involvement in adipogenesis and glucose homeostasis. PPARγ activity has also been associated with neuroprotection in different neurological disorders, but the mechanisms involved in PPARγ effects in the nervous system are still unknown. Here we describe a new functional role for PPARγ in neuronal responses to injury. We found both PPAR transcripts and protein within sensory axons and observed an increase in PPARγ protein levels after sciatic nerve crush. This was correlated with increased retrograde transport of PPARγ after injury, increased association of PPARγ with the molecular motor dynein, and increased nuclear accumulation of PPARγ in cell bodies of sensory neurons. Furthermore, PPARγ antagonists attenuated the response of sensory neurons to sciatic nerve injury, and inhibited axonal growth of both sensory and cortical neurons in culture. Thus, axonal PPARγ is involved in neuronal injury responses required for axonal regeneration. Since PPARγ is a major molecular target of the thiazolidinedione (TZD) class of drugs used in the treatment of type II diabetes, several pharmaceutical agents with acceptable safety profiles in humans are available. Our findings provide motivation and rationale for the evaluation of such agents for efficacy in central and peripheral nerve injuries. PMID:26446277

  17. Patterns of growth, axonal extension and axonal arborization of neuronal lineages in the developing Drosophila brain

    OpenAIRE

    Larsen, Camilla; Shy, Diana; Spindler, Shana R; Fung, Siaumin; Pereanu, Wayne; Younossi -Hartenstein, Amelia; Hartenstein, Volker

    2009-01-01

    The Drosophila central brain is composed of approximately 100 paired lineages, with most lineages comprising 100–150 neurons. Most lineages have a number of important characteristics in common. Typically, neurons of a lineage stay together as a coherent cluster and project their axons into a coherent bundle visible from late embryo to adult. Neurons born during the embryonic period form the primary axon tracts (PATs) that follow stereotyped pathways in the neuropile. Apoptotic cell death remo...

  18. 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

  19. Mislocalization of neuronal mitochondria reveals regulation of Wallerian degeneration and NMNAT/WLDS-mediated axon protection independent of axonal mitochondria

    OpenAIRE

    Kitay, Brandon M.; McCormack, Ryan; Wang, Yunfang; Tsoulfas, Pantelis; Zhai, R. Grace

    2013-01-01

    Axon degeneration is a common and often early feature of neurodegeneration that correlates with the clinical manifestations and progression of neurological disease. Nicotinamide mononucleotide adenylytransferase (NMNAT) is a neuroprotective factor that delays axon degeneration following injury and in models of neurodegenerative diseases suggesting a converging molecular pathway of axon self-destruction. The underlying mechanisms have been under intense investigation and recent reports suggest...

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

    OpenAIRE

    Edison Matos Nóvak; Lineu Cesar Werneck

    1984-01-01

    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.

  1. 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.

  2. Dynamic Axonal Translation in Developing and Mature Visual Circuits.

    Science.gov (United States)

    Shigeoka, Toshiaki; Jung, Hosung; Jung, Jane; Turner-Bridger, Benita; Ohk, Jiyeon; Lin, Julie Qiaojin; Amieux, Paul S; Holt, Christine E

    2016-06-30

    Local mRNA translation mediates the adaptive responses of axons to extrinsic signals, but direct evidence that it occurs in mammalian CNS axons in vivo is scant. We developed an axon-TRAP-RiboTag approach in mouse that allows deep-sequencing analysis of ribosome-bound mRNAs in the retinal ganglion cell axons of the developing and adult retinotectal projection in vivo. The embryonic-to-postnatal axonal translatome comprises an evolving subset of enriched genes with axon-specific roles, suggesting distinct steps in axon wiring, such as elongation, pruning, and synaptogenesis. Adult axons, remarkably, have a complex translatome with strong links to axon survival, neurotransmission, and neurodegenerative disease. Translationally co-regulated mRNA subsets share common upstream regulators, and sequence elements generated by alternative splicing promote axonal mRNA translation. Our results indicate that intricate regulation of compartment-specific mRNA translation in mammalian CNS axons supports the formation and maintenance of neural circuits in vivo. PMID:27321671

  3. 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.

  4. 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.

  5. Axons of sacral preganglionic neurons in the cat: II. Axon collaterals.

    Science.gov (United States)

    Morgan, C W

    2001-01-01

    Axon collaterals were identified in 21 of 24 preganglionic neurons in the lateral band of the sacral parasympathetic nucleus of the cat. Following the intracellular injection of HRP or neurobiotin the axons from 20 of these neurons were followed and 53 primary axon collaterals were found to originate from unmyelinated segments and from nodes of Ranvier. Detailed mapping done in the five best labeled cells showed bilateral axon collaterals distributions up to 25,000 microm in length with 950 varicosities and unilateral distributions up to 12,561 microm with 491 varicosities. The axon collaterals appeared to be unmyelinated, which was confirmed at EM, and were small in diameter (average 0.3 microm). Varicosities were located mostly in laminae I, V, VII, VIII and X and in the lateral funiculi. Most varicosities were not in contact with visible structures but some were seen in close apposition to Nissl stained somata and proximal dendrites. Varicosities had average minor diameters of 1.3 microm and major diameters of 2.3 microm. Most were boutons en passant while 10-20% were boutons termineaux. EM revealed axodendritic and axoaxonic synapses formed by varicosities and by the axons between varicosities. It is estimated that the most extensive of these axon collaterals systems may contact over 200 spinal neurons in multiple locations. These data lead to the conclusion that sacral preganglionic neurons have multiple functions within the spinal cord in addition to serving their target organ. As most preganglionic neurons in this location innervate the urinary bladder, it is possible that bladder preganglionic neurons have multiple functions.

  6. Diferentes estados de maduración de los frutos de Roystonea regia afectan su efecto sobre el aumento del tamaño de la próstata inducido por testosterona en ratas

    OpenAIRE

    Arruzazabala, María de Lourdes; Molina, Vivian; Carbajal, Daisy; Más, Rosa; González Canavaciolo, Víctor L.; Rodríguez, Eduardo J.; Marrero Delange, David

    2008-01-01

    En este trabajo se han comparado los efectos de extractos lipídicos obtenidos de los frutos de Roystonea regia de diferentes estados de maduración sobre la hiperplasia prostática inducida por testosterona en ratas. Frutos maduros, pintones y verdes fueron colectados y procesados para la obtención de extractos lipídicos, cuyo contenido de ácidos grasos fue analizado por cromatografía gaseosa. A medida que los frutos maduran la concentración de ácido láurico aumenta y el oleico disminuye, mient...

  7. Axonal loss and neuroprotection in optic neuropathies.

    Science.gov (United States)

    Levin, Leonard A

    2007-06-01

    Most optic neuropathies do not have effective treatments. Examples are ischemic optic neuropathy, Leber hereditary optic neuropathy, optic neuritis, and traumatic optic neuropathy. In some cases, the pathophysiology of the optic nerve injury is not fully understood. For example, while the demyelinative aspects of optic neuritis have been studied, the mechanism by which the axonal loss occurs is less apparent. In other cases, although the pathophysiology of the optic neuropathy may be understood, there is difficulty treating the disease, for example, with traumatic optic neuropathy. In response to this therapeutic dearth, the concept of neuroprotection has arisen. Neuroprotection is a therapeutic paradigm for preventing death of neurons from injury and maintaining function. In optic neuropathies, the corresponding neuron is the retinal ganglion cell. These cells are unable to divide, and optic neuropathies irrevocably result in their death; therefore, the primary target of neuroprotection are retinal ganglion cells and their axons. This review emphasizes that most optic neuropathies are axonal and thus good targets for neuroprotection. PMID:17508035

  8. 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".

  9. 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.

  10. 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.

  11. 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

  12. Focal axonal swellings and associated ultrastructural changes attenuate conduction velocity in central nervous system axons: a computer modeling study.

    Science.gov (United States)

    Kolaric, Katarina V; Thomson, Gemma; Edgar, Julia M; Brown, Angus M

    2013-08-01

    The constancy of action potential conduction in the central nervous system (CNS) relies on uniform axon diameter coupled with fidelity of the overlying myelin providing high-resistance, low capacitance insulation. Whereas the effects of demyelination on conduction have been extensively studied/modeled, equivalent studies on the repercussions for conduction of axon swelling, a common early pathological feature of (potentially reversible) axonal injury, are lacking. The recent description of experimentally acquired morphological and electrical properties of small CNS axons and oligodendrocytes prompted us to incorporate these data into a computer model, with the aim of simulating the effects of focal axon swelling on action potential conduction. A single swelling on an otherwise intact axon, as occurs in optic nerve axons of Cnp1 null mice caused a small decrease in conduction velocity. The presence of single swellings on multiple contiguous internodal regions (INR), as likely occurs in advanced disease, caused qualitatively similar results, except the dimensions of the swellings required to produce equivalent attenuation of conduction were significantly decreased. Our simulations of the consequences of metabolic insult to axons, namely, the appearance of multiple swollen regions, accompanied by perturbation of overlying myelin and increased axolemmal permeability, contained within a single INR, revealed that conduction block occurred when the dimensions of the simulated swellings were within the limits of those measured experimentally, suggesting that multiple swellings on a single axon could contribute to axonal dysfunction, and that increased axolemmal permeability is the decisive factor that promotes conduction block. PMID:24303138

  13. Early ultrastructural defects of axons and axon-glia junctions in mice lacking expression of Cnp1.

    Science.gov (United States)

    Edgar, Julia M; McLaughlin, Mark; Werner, Hauke B; McCulloch, Mailis C; Barrie, Jennifer A; Brown, Angus; Faichney, Andrew Blyth; Snaidero, Nicolas; Nave, Klaus-Armin; Griffiths, Ian R

    2009-12-01

    Most axons in the central nervous system (CNS) are surrounded by a multilayered myelin sheath that promotes fast, saltatory conduction of electrical impulses. By insulating the axon, myelin also shields the axoplasm from the extracellular milieu. In the CNS, oligodendrocytes provide support for the long-term maintenance of myelinated axons, independent of the myelin sheath. Here, we use electron microscopy and morphometric analyses to examine the evolution of axonal and oligodendroglial changes in mice deficient in 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) and in mice deficient in both CNP and proteolipid protein (PLP/DM20). We show that CNP is necessary for the formation of a normal inner tongue process of oligodendrocytes that myelinate small diameter axons. We also show that axonal degeneration in Cnp1 null mice is present very early in postnatal life. Importantly, compact myelin formed by transplanted Cnp1 null oligodendrocytes induces the same degenerative changes in shiverer axons that normally are dysmyelinated but structurally intact. Mice deficient in both CNP and PLP develop a more severe axonal phenotype than either single mutant, indicating that the two oligodendroglial proteins serve distinct functions in supporting the myelinated axon. These observations support a model in which the trophic functions of oligodendrocytes serve to offset the physical shielding of axons by myelin membranes. PMID:19459211

  14. 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...

  15. 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.

  16. 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.

  17. Action potentials reliably invade axonal arbors of rat neocortical neurons

    OpenAIRE

    Cox, Charles L.; Denk, Winfried; Tank, David W.; Svoboda, Karel

    2000-01-01

    Neocortical pyramidal neurons have extensive axonal arborizations that make thousands of synapses. Action potentials can invade these arbors and cause calcium influx that is required for neurotransmitter release and excitation of postsynaptic targets. Thus, the regulation of action potential invasion in axonal branches might shape the spread of excitation in cortical neural networks. To measure the reliability and extent of action potential invasion into axonal arbors, we have used two-photon...

  18. Myelin sheath survival after guanethidine-induced axonal degeneration

    OpenAIRE

    1992-01-01

    Membrane-membrane interactions between axons and Schwann cells are required for initial myelin formation in the peripheral nervous system. However, recent studies of double myelination in sympathetic nerve have indicated that myelin sheaths continue to exist after complete loss of axonal contact (Kidd, G. J., and J. W. Heath. 1988. J. Neurocytol. 17:245-261). This suggests that myelin maintenance may be regulated either by diffusible axonal factors or by nonaxonal mechanisms. To test these hy...

  19. Axon Regeneration in the Peripheral and Central Nervous Systems

    OpenAIRE

    Huebner, Eric A.; Strittmatter, Stephen M

    2009-01-01

    Axon regeneration in the mature mammalian central nervous system (CNS) is extremely limited after injury. Consequently, functional deficits persist after spinal cord injury (SCI), traumatic brain injury, stroke, and related conditions that involve axonal disconnection. This situation differs from that in the mammalian peripheral nervous system (PNS), where long- distance axon regeneration and substantial functional recovery can occur in the adult. Both extracellular molecules and the intrinsi...

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Patterns of growth, axonal extension and axonal arborization of neuronal lineages in the developing Drosophila brain.

    Science.gov (United States)

    Larsen, Camilla; Shy, Diana; Spindler, Shana R; Fung, Siaumin; Pereanu, Wayne; Younossi-Hartenstein, Amelia; Hartenstein, Volker

    2009-11-15

    The Drosophila central brain is composed of approximately 100 paired lineages, with most lineages comprising 100-150 neurons. Most lineages have a number of important characteristics in common. Typically, neurons of a lineage stay together as a coherent cluster and project their axons into a coherent bundle visible from late embryo to adult. Neurons born during the embryonic period form the primary axon tracts (PATs) that follow stereotyped pathways in the neuropile. Apoptotic cell death removes an average of 30-40% of primary neurons around the time of hatching. Secondary neurons generated during the larval period form secondary axon tracts (SATs) that typically fasciculate with their corresponding primary axon tract. SATs develop into the long fascicles that interconnect the different compartments of the adult brain. Structurally, we distinguish between three types of lineages: PD lineages, characterized by distinct, spatially separate proximal and distal arborizations; C lineages with arborizations distributed continuously along the entire length of their tract; D lineages that lack proximal arborizations. Arborizations of many lineages, in particular those of the PD type, are restricted to distinct neuropile compartments. We propose that compartments are "scaffolded" by individual lineages, or small groups thereof. Thereby, the relatively small number of primary neurons of each primary lineage set up the compartment map in the late embryo. Compartments grow during the larval period simply by an increase in arbor volume of primary neurons. Arbors of secondary neurons form within or adjacent to the larval compartments, resulting in smaller compartment subdivisions and additional, adult specific compartments. PMID:19538956

  8. Focal axonal swellings and associated ultrastructural changes attenuate conduction velocity in central nervous system axons: a computer modeling study

    OpenAIRE

    Kolaric, Katarina V; Thomson, Gemma; Edgar, Julia M; Brown, Angus M.

    2013-01-01

    The constancy of action potential conduction in the central nervous system (CNS) relies on uniform axon diameter coupled with fidelity of the overlying myelin providing high-resistance, low capacitance insulation. Whereas the effects of demyelination on conduction have been extensively studied/modeled, equivalent studies on the repercussions for conduction of axon swelling, a common early pathological feature of (potentially reversible) axonal injury, are lacking. The recent description of ex...

  9. 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.

  10. 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.

  11. Efectos y aplicaciones de birrefringencia inducida en Redes de Bragg en fibra óptica

    OpenAIRE

    Botero Cadavid, Juan Fernando

    2007-01-01

    Resumen: las fibras ópticas han sido empleadas durante muchos años como sistemas de transmisión de información en comunicaciones y han evolucionado bastante desde su invención por las ventajas que presentan respecto a otras técnicas. Simultáneamente con su evolución, se presentaron avances como el mejoramiento de fuentes de luz y en fotodetectores; actualmente la tendencia es que muchos de estos sistemas se encuentren directamente integrados a fibra óptica. Además de sistemas de comunicacione...

  12. 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

  13. New insights into mRNA trafficking in axons

    NARCIS (Netherlands)

    Gumy, Laura; Katrukha, Eugene; Kapitein, Lukas; Hoogenraad, Casper

    2014-01-01

    In recent years, it has been demonstrated that mRNAs localize to axons of young and mature central and peripheral nervous system neurons in culture and in vivo. Increasing evidence is supporting a fundamental role for the local translation of these mRNAs in neuronal function by regulating axon growt

  14. 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...

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

    OpenAIRE

    Salazar Bugueño, Ana María

    2013-01-01

    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, el c...

  16. 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.

  17. Receptor Tyrosine Kinases: Molecular Switches Regulating CNS Axon Regeneration

    Directory of Open Access Journals (Sweden)

    Vasanthy Vigneswara

    2012-01-01

    Full Text Available The poor or lack of injured adult central nervous system (CNS axon regeneration results in devastating consequences and poor functional recovery. The interplay between the intrinsic and extrinsic factors contributes to robust inhibition of axon regeneration of injured CNS neurons. The insufficient or lack of trophic support for injured neurons is considered as one of the major obstacles contributing to their failure to survive and regrow their axons after injury. In the CNS, many of the signalling pathways associated with neuronal survival and axon regeneration are regulated by several classes of receptor tyrosine kinases (RTK that respond to a variety of ligands. This paper highlights and summarises the most relevant recent findings pertinent to different classes of the RTK family of molecules, with a particular focus on elucidating their role in CNS axon regeneration.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. Brain injury tolerance limit based on computation of axonal strain.

    Science.gov (United States)

    Sahoo, Debasis; Deck, Caroline; Willinger, Rémy

    2016-07-01

    Traumatic brain injury (TBI) is the leading cause of death and permanent impairment over the last decades. In both the severe and mild TBIs, diffuse axonal injury (DAI) is the most common pathology and leads to axonal degeneration. Computation of axonal strain by using finite element head model in numerical simulation can enlighten the DAI mechanism and help to establish advanced head injury criteria. The main objective of this study is to develop a brain injury criterion based on computation of axonal strain. To achieve the objective a state-of-the-art finite element head model with enhanced brain and skull material laws, was used for numerical computation of real world head trauma. The implementation of new medical imaging data such as, fractional anisotropy and axonal fiber orientation from Diffusion Tensor Imaging (DTI) of 12 healthy patients into the finite element brain model was performed to improve the brain constitutive material law with more efficient heterogeneous anisotropic visco hyper-elastic material law. The brain behavior has been validated in terms of brain deformation against Hardy et al. (2001), Hardy et al. (2007), and in terms of brain pressure against Nahum et al. (1977) and Trosseille et al. (1992) experiments. Verification of model stability has been conducted as well. Further, 109 well-documented TBI cases were simulated and axonal strain computed to derive brain injury tolerance curve. Based on an in-depth statistical analysis of different intra-cerebral parameters (brain axonal strain rate, axonal strain, first principal strain, Von Mises strain, first principal stress, Von Mises stress, CSDM (0.10), CSDM (0.15) and CSDM (0.25)), it was shown that axonal strain was the most appropriate candidate parameter to predict DAI. The proposed brain injury tolerance limit for a 50% risk of DAI has been established at 14.65% of axonal strain. This study provides a key step for a realistic novel injury metric for DAI. PMID:27038501

  3. La administración preventiva de cardiotrofina-1 disminuye la gravedad de la colitis ulcerosa inducida por dextrano sulfato de sodio

    OpenAIRE

    Sánchez Garrido, Ana Isabel

    2015-01-01

    [ES]La enfermedad inflamatoria intestinal crónica (EIIC) surge de la interacción entre las bacterias de la luz intestinal y la mucosa y comprende la colitis ulcerosa (CU), la enfermedad de Crohn (EC) y la colitis inclasificable (CI) . Aunque la etiopatogenia de la EIIC no ha sido claramente dilucidada, se atribuye a una compleja interacción entre factores genéticos, ambientales, microbianos y diversos factores inmunes que incluyen péptidos quimiotácticos y citocinas proinflamatorias. La disr...

  4. 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.

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

    OpenAIRE

    Luisa L. Rocha

    2008-01-01

    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), ...

  6. Fisuración inducida por hidrógeno de aceros soldables microaleados: caracterización y modelo de comportamiento

    OpenAIRE

    Álvarez Laso, José Alberto

    2011-01-01

    RESUMEN: Las condiciones ambientales de trabajo de los aceros estructurales y de conducciones en instalaciones energéticas y petrolíferas han puesto en evidencia la necesidad de encontrar una metodología de caracterización de su resistencia a la fisuración, tanto en régimen de dominio elástico como elastoplástico. Este trabajo recoge una metodología experimental y analítica adecuada para ser aplicada a los procesos de fisuración estudiados sobre probetas y estructuras, en particular a aquéllo...

  7. Allergy in humans induced by saliva from insects from the family culicidae ALERGIA EN EL HUMANO INDUCIDA POR LA SALIVA DE INSECTOS DE LA FAMILIA CULICIDAE

    OpenAIRE

    Lígia Inés Moncada-Álvarez; Myriam Janeth Salazar-Terreros; Myriam Consuelo López-Páez

    2011-01-01

    A review was made of the molecules which are inoculated by insects from the family Culicidae when biting and the mechanisms used by their hosts to contract them, as well as some of these molecules, especially enzymes which become allergens inducing a broad spectrum response ranging from a papule when being bitten to a full-blown anaphylactic reaction. The possibility of diagnosis using wild molecules and recombinant antigens was also analyzed, as well as treatment guidelines.Se hace una revis...

  8. Vulnerabilidad de la movilidad en Quito inducida por la exposición a las inundaciones de un medio de transporte clave: el trolebús

    OpenAIRE

    Demoraes, Florent

    2002-01-01

    International audience En este texto se analiza la exposición a inundaciones de un elemento clave del sistema de transporte del Distrito Metropolitano de Quito: el trolebús. Se presenta los principales factores que explican su alto grado de vulnerabilidad ante inundaciones, factores que remiten tanto a sus características técnicas como a vulnerabilidades que derivan de las modalidades de desarrollo de la ciudad de Quito. Este trabajo fue presentado en el duodécimo congreso panamericano de ...

  9. CARACTERIZACIÓN EXPERIMENTAL DE LA CONCENTRACIÓN DE HOLLÍN EN LLAMAS DIESEL MEDIANTE INCANDESCENCIA INDUCIDA POR LÁSER

    OpenAIRE

    BUITRAGO GARCÍA, JORGE ENRIQUE

    2016-01-01

    [EN] Laser-induced incandescence (LII) is an optical diagnostic technique that can be used to measure the concentration and primary-particle size distributions of soot with high selectivity. This technique consists of rapid particle heating from the local ambient temperature to close to the soot sublimation temperature (~4000 K) by means of a highly energetic laser source, and the immediate recording of the strong thermal radiation as a result of a complex heat and mass transfer balance. The ...

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

    OpenAIRE

    Muñoz Ortiz, Édison; Arango Toro, Clara María; Vásquez Mejía, Esdras Martín; Gutiérrez Restrepo, Johnayro; Montoya Escobar, Julián Felipe; Villa Franco, Juan Pablo

    2012-01-01

    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.

  11. 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.

  12. 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.

  13. 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)

  14. 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.

  15. El ensayo de micronúcleos como medida de inestabilidad genética inducida por agentes genotóxicos

    OpenAIRE

    Zalacain, M. (Marta); SIERRASESUMAGA, L.; Patiño, A. (Ana)

    2005-01-01

    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 division; they reflect the existence of chromosomal aberrations and are originated by chromosomal brea...

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. Intra-axonal myosin and actin in nerve regeneration.

    Science.gov (United States)

    McQuarrie, Irvine G; Lund, Linda M

    2009-10-01

    A focused review of sciatic nerve regeneration in the rat model, based on research conducted by the authors, is presented. We examine structural proteins carried distally in the axon by energy-requiring motor enzymes, using protein chemistry and molecular biology techniques in combination with immunohistochemistry. Relevant findings from other laboratories are cited and discussed. The general conclusion is that relatively large amounts of actin and tubulin are required to construct a regenerating axon and that these materials mainly originate in the parent axon. The motor enzymes that carry these proteins forward as macromolecules include kinesin and dynein but probably also include myosin. PMID:19927086

  1. 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.

  2. Estatus de parámetros oxidativos y del gen p53 en sangre de niños en edad escolar de zonas afectadas por el accidente nuclear de Chernobyl.

    OpenAIRE

    García Mora, Mª Carmen

    2004-01-01

    RESUMEN Tras el accidente nuclear de Chernobyl producido el 26 de abril de 1986 se liberaron muchos radioisótopos, produciendo la contaminación del medio ambiente, con la consiguiente implicación sobre la salud de las personas afectadas. La irradiación produce su efecto sobre el material biológico de manera directa, como consecuencia inmediata de la ionización inducida por la irradiación y de manera indirecta, que al interaccionar sobre cualquier estructura celular, esencialmente el agua t...

  3. 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...

  4. Axon diameter mapping in crossing fibers with diffusion MRI

    DEFF Research Database (Denmark)

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

    2011-01-01

    tissue than measures derived from diffusion tensor imaging. Most existing techniques for axon diameter mapping assume a single axon orientation in the tissue model, which limits their application to only the most coherently oriented brain white matter, such as the corpus callosum, where the single...... orientation assumption is a reasonable one. However, fiber crossings and other complex configurations are widespread in the brain. In such areas, the existing techniques will fail to provide useful axon diameter indices for any of the individual fiber populations. We propose a novel crossing fiber tissue...... of the technique by establishing reasonable axon diameter indices in the crossing region at the interface of the cingulum and the corpus callosum....

  5. Internodal function in normal and regenerated mammalian axons

    DEFF Research Database (Denmark)

    Moldovan, M; Krarup, C

    2007-01-01

    human nerves. CONCLUSION: The data suggest that persistently shorter regenerated internodes lead to increased Na+/K+-pump activity in response to increased Na+ entry during conduction. This may impair axonal function during prolonged repetitive activity and drain the energy reserves of the axons.......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...

  6. RGM is a repulsive guidance molecule for retinal axons

    DEFF Research Database (Denmark)

    Monnier, Philippe P; Sierra, Ana; Macchi, Paolo;

    2002-01-01

    Axons rely on guidance cues to reach remote targets during nervous system development. A well-studied model system for axon guidance is the retinotectal projection. The retina can be divided into halves; the nasal half, next to the nose, and the temporal half. A subset of retinal axons, those from...... the temporal half, is guided by repulsive cues expressed in a graded fashion in the optic tectum, part of the midbrain. Here we report the cloning and functional characterization of a membrane-associated glycoprotein, which we call RGM (repulsive guidance molecule). This molecule shares no sequence homology...... with known guidance cues, and its messenger RNA is distributed in a gradient with increasing concentration from the anterior to posterior pole of the embryonic tectum. Recombinant RGM at low nanomolar concentration induces collapse of temporal but not of nasal growth cones and guides temporal retinal axons...

  7. 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.

  8. Changes in prefrontal axons may disrupt the network in autism

    OpenAIRE

    Zikopoulos, Basilis; Barbas, Helen

    2010-01-01

    Neural communication is disrupted in autism by unknown mechanisms. Here we examined whether in autism there are changes in axons, which are the conduit for neural communication. We investigated single axons and their ultrastructure in the white matter of post-mortem human brain tissue below the anterior cingulate cortex (ACC), orbitofrontal (OFC), and lateral (LPFC) prefrontal cortices, which are associated with attention, social interactions, and emotions and have been consistently implicate...

  9. Fcγ receptor-mediated inflammation inhibits axon regeneration.

    Directory of Open Access Journals (Sweden)

    Gang Zhang

    Full Text Available Anti-glycan/ganglioside antibodies are the most common immune effectors found in patients with Guillain-Barré Syndrome, which is a peripheral autoimmune neuropathy. We previously reported that disease-relevant anti-glycan autoantibodies inhibited axon regeneration, which echo the clinical association of these antibodies and poor recovery in Guillain-Barré Syndrome. However, the specific molecular and cellular elements involved in this antibody-mediated inhibition of axon regeneration are not previously defined. This study examined the role of Fcγ receptors and macrophages in the antibody-mediated inhibition of axon regeneration. A well characterized antibody passive transfer sciatic nerve crush and transplant models were used to study the anti-ganglioside antibody-mediated inhibition of axon regeneration in wild type and various mutant and transgenic mice with altered expression of specific Fcγ receptors and macrophage/microglia populations. Outcome measures included behavior, electrophysiology, morphometry, immunocytochemistry, quantitative real-time PCR, and western blotting. We demonstrate that the presence of autoantibodies, directed against neuronal/axonal cell surface gangliosides, in the injured mammalian peripheral nerves switch the proregenerative inflammatory environment to growth inhibitory milieu by engaging specific activating Fcγ receptors on recruited monocyte-derived macrophages to cause severe inhibition of axon regeneration. Our data demonstrate that the antibody orchestrated Fcγ receptor-mediated switch in inflammation is one mechanism underlying inhibition of axon regeneration. These findings have clinical implications for nerve repair and recovery in antibody-mediated immune neuropathies. Our results add to the complexity of axon regeneration in injured peripheral and central nervous systems as adverse effects of B cells and autoantibodies on neural injury and repair are increasingly recognized.

  10. Axonal neuropathy associated with monoclonal gammopathy of undetermined significance

    OpenAIRE

    GORSON, K.; Ropper, A.

    1997-01-01

    OBJECTIVE—The neuropathy associated with monoclonal gammopathy of undetermined significance (MGUS) is typically a predominantly demyelinating process that may have additional features of axonal degeneration. Sixteen patients with MGUS and a pure or predominantly axonal neuropathy are reported and compared with 20 consecutive patients with demyelinating neuropathy and MGUS who were seen during the same period.
METHODS—Retrospective review of a consecutive series of patients w...

  11. 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.

  12. Axonal maintenance, glia, exosomes, and heat shock proteins

    OpenAIRE

    Michael Tytell; Lasek, Raymond J.; Harold Gainer

    2016-01-01

    Of all cellular specializations, the axon is especially distinctive because it is a narrow cylinder of specialized cytoplasm called axoplasm with a length that may be orders of magnitude greater than the diameter of the cell body from which it originates. Thus, the volume of axoplasm can be much greater than the cytoplasm in the cell body. This fact raises a logistical problem with regard to axonal maintenance. Many of the components of axoplasm, such as soluble proteins and cytoskeleton, are...

  13. 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.

  14. 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

  15. Wnt5a regulates midbrain dopaminergic axon growth and guidance.

    Directory of Open Access Journals (Sweden)

    Brette D Blakely

    Full Text Available During development, precise temporal and spatial gradients are responsible for guiding axons to their appropriate targets. Within the developing ventral midbrain (VM the cues that guide dopaminergic (DA axons to their forebrain targets remain to be fully elucidated. Wnts are morphogens that have been identified as axon guidance molecules. Several Wnts are expressed in the VM where they regulate the birth of DA neurons. Here, we describe that a precise temporo-spatial expression of Wnt5a accompanies the development of nigrostriatal projections by VM DA neurons. In mice at E11.5, Wnt5a is expressed in the VM where it was found to promote DA neurite and axonal growth in VM primary cultures. By E14.5, when DA axons are approaching their striatal target, Wnt5a causes DA neurite retraction in primary cultures. Co-culture of VM explants with Wnt5a-overexpressing cell aggregates revealed that Wnt5a is capable of repelling DA neurites. Antagonism experiments revealed that the effects of Wnt5a are mediated by the Frizzled receptors and by the small GTPase, Rac1 (a component of the non-canonical Wnt planar cell polarity pathway. Moreover, the effects were specific as they could be blocked by Wnt5a antibody, sFRPs and RYK-Fc. The importance of Wnt5a in DA axon morphogenesis was further verified in Wnt5a-/- mice, where fasciculation of the medial forebrain bundle (MFB as well as the density of DA neurites in the MFB and striatal terminals were disrupted. Thus, our results identify a novel role of Wnt5a in DA axon growth and guidance.

  16. 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.

  17. Regulation of Microtubule Dynamics in Axon Regeneration: Insights from C. elegans [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Ngang Heok Tang

    2016-04-01

    Full Text Available The capacity of an axon to regenerate is regulated by its external environment and by cell-intrinsic factors. Studies in a variety of organisms suggest that alterations in axonal microtubule (MT dynamics have potent effects on axon regeneration. We review recent findings on the regulation of MT dynamics during axon regeneration, focusing on the nematode Caenorhabditis elegans. In C. elegans the dual leucine zipper kinase (DLK promotes axon regeneration, whereas the exchange factor for Arf6 (EFA-6 inhibits axon regeneration. Both DLK and EFA-6 respond to injury and control axon regeneration in part via MT dynamics. How the DLK and EFA-6 pathways are related is a topic of active investigation, as is the mechanism by which EFA-6 responds to axonal injury. We evaluate potential candidates, such as the MT affinity-regulating kinase PAR-1/MARK, in regulation of EFA-6 and axonal MT dynamics in regeneration.

  18. Coordinated motor neuron axon growth and neuromuscular synaptogenesis are promoted by CPG15 in vivo.

    Science.gov (United States)

    Javaherian, Ashkan; Cline, Hollis T

    2005-02-17

    We have used in vivo time-lapse two-photon imaging of single motor neuron axons labeled with GFP combined with labeling of presynaptic vesicle clusters and postsynaptic acetylcholine receptors in Xenopus laevis tadpoles to determine the dynamic rearrangement of individual axon branches and synaptogenesis during motor axon arbor development. Control GFP-labeled axons are highly dynamic during the period when axon arbors are elaborating. Axon branches emerge from sites of synaptic vesicle clusters. These data indicate that motor neuron axon elaboration and synaptogenesis are concurrent and iterative. We tested the role of Candidate Plasticity Gene 15 (CPG15, also known as Neuritin), an activity-regulated gene that is expressed in the developing motor neurons in this process. CPG15 expression enhances the development of motor neuron axon arbors by promoting neuromuscular synaptogenesis and by increasing the addition of new axon branches. PMID:15721237

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

    Directory of Open Access Journals (Sweden)

    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.

  20. 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.

  1. Highly effective photonic cue for repulsive axonal guidance.

    Directory of Open Access Journals (Sweden)

    Bryan J Black

    Full Text Available In vivo nerve repair requires not only the ability to regenerate damaged axons, but most importantly, the ability to guide developing or regenerating axons along paths that will result in functional connections. Furthermore, basic studies in neuroscience and neuro-electronic interface design require the ability to construct in vitro neural circuitry. Both these applications require the development of a noninvasive, highly effective tool for axonal growth-cone guidance. To date, a myriad of technologies have been introduced based on chemical, electrical, mechanical, and hybrid approaches (such as electro-chemical, optofluidic flow and photo-chemical methods. These methods are either lacking in desired spatial and temporal selectivity or require the introduction of invasive external factors. Within the last fifteen years however, several attractive guidance cues have been developed using purely light based cues to achieve axonal guidance. Here, we report a novel, purely optical repulsive guidance technique that uses low power, near infrared light, and demonstrates the guidance of primary goldfish retinal ganglion cell axons through turns of up to 120 degrees and over distances of ∼90 µm.

  2. Subtypes of GABAergic neurons project axons in the neocortex

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    Anders Victor ePetersen

    2015-10-01

    Full Text Available 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 in live tissue can be difficult because its identification is not always reliable. Here we provide a new technique allowing a fast and reliable identification of the AIS in live brain slice preparations. By simultaneous recoding of extracellular local field potentials and whole-cell patch-clamp recording 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 the brain.

  5. Involvement of SARA in Axon and Dendrite Growth.

    Science.gov (United States)

    Arias, Cristina Isabel; Siri, Sebastián Omar; Conde, Cecilia

    2015-01-01

    SARA (Smad Anchor for Receptor Activation) plays a crucial role in Rab5-mediated endocytosis in cell lines localizing to early endosomes where it regulates morphology and function. Here, we analyzed the role of SARA during neuronal development and tested whether it functions as a regulator of endocytic trafficking of selected axonal and membrane proteins. Suppression of SARA perturbs the appearance of juxtanuclear endocytic recycling compartments and the neurons show long axons with large growth cones. Furthermore, surface distribution of the cell adhesion molecule L1 in axons and the fusion of vesicles containing transferring receptor (TfR) in dendrites were increased in neurons where SARA was silenced. Conversely, SARA overexpression generated large early endosomes and reduced neurite outgrowth. Taken together, our findings suggest a significant contribution of SARA to key aspects of neuronal development, including neurite formation. PMID:26405814

  6. 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.

  7. 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.

  8. Axon-glial interactions in the central nervous system

    OpenAIRE

    Butt, Arthur; Bay, Virginia

    2011-01-01

    Axon-glial interactions are critical for brain information transmission and processing. In the CNS, this is a function of the major types of glia – astrocytes, oligodendrocytes and novel NG2-glia. This special issue of the Journal of Anatomy comprises contributions arising from a symposium entitled ‘Axon-glial interactions in the CNS’, held at the University of Portsmouth, UK in July 2010. The aim of the special issue is to bring together an international group of experts to demonstrate the c...

  9. 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.

  10. Networks of Polarized Actin Filaments in the Axon Initial Segment Provide a Mechanism for Sorting Axonal and Dendritic Proteins

    Directory of Open Access Journals (Sweden)

    Kaori Watanabe

    2012-12-01

    Full Text Available Trafficking of proteins specifically to the axonal or somatodendritic membrane allows neurons to establish and maintain polarized compartments with distinct morphology and function. Diverse evidence suggests that an actin-dependent vesicle filter within the axon initial segment (AIS plays a critical role in polarized trafficking; however, no distinctive actin-based structures capable of comprising such a filter have been found within the AIS. Here, using correlative light and scanning electron microscopy, we visualized networks of actin filaments several microns wide within the AIS of cortical neurons in culture. Individual filaments within these patches are predominantly oriented with their plus ends facing toward the cell body, consistent with models of filter selectivity. Vesicles carrying dendritic proteins are much more likely to stop in regions occupied by the actin patches than in other regions, indicating that the patches likely prevent movement of dendritic proteins to the axon and thereby act as a vesicle filter.

  11. Membrane potential dynamics of axons in cultured hippocampal neurons probed by second-harmonic-generation imaging

    Science.gov (United States)

    Nuriya, Mutsuo; Yasui, Masato

    2010-03-01

    The electrical properties of axons critically influence the nature of communication between neurons. However, due to their small size, direct measurement of membrane potential dynamics in intact and complex mammalian axons has been a challenge. Furthermore, quantitative optical measurements of axonal membrane potential dynamics have not been available. To characterize the basic principles of somatic voltage signal propagation in intact axonal arbors, second-harmonic-generation (SHG) imaging is applied to cultured mouse hippocampal neurons. When FM4-64 is applied extracellularly to dissociated neurons, whole axonal arbors are visualized by SHG imaging. Upon action potential generation by somatic current injection, nonattenuating action potentials are recorded in intact axonal arbors. Interestingly, however, both current- and voltage-clamp recordings suggest that nonregenerative subthreshold somatic voltage changes at the soma are poorly conveyed to these axonal sites. These results reveal the nature of membrane potential dynamics of cultured hippocampal neurons, and further show the possibility of SHG imaging in physiological investigations of axons.

  12. 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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Efectos protectores de la oleoiletanolamida en la neuroinflamación inducida por la administración de lipopolisacárido o por el consumo intensivo de alcohol

    OpenAIRE

    Antón Valadés, María

    2015-01-01

    La neuroinflamación es un fenómeno que contribuye a la progresión y agravamiento de enfermedades neurodegenerativas y neuropsiquiátricas, incluida la adicción a sustancias como el alcohol. Se han descrito acciones neuroprotectoras de mediadores lipídicos naturales derivados de la membrana celular, tales como la oleoiletanolamida, y su congénere la palmitoiletanolamida, ambos pertenecientes a la familia de las aciletanolamidas. Se desconoce con exactitud el potencial efecto terapéutico de esto...

  14. Modulación de la actividad dopa-decarboxilasa central evaluada mediante PET con 18-F-dopa inducida por la administración crónica de levodopa en macacos con parkinsonismo inducido por MPTP

    OpenAIRE

    M. Riverol; Luquin, M R

    2013-01-01

    La enfermedad de Parkinson (EP) es una entidad frecuentre que afecta fundamentalmente a personas de edad avanzada. Los fármacos más utilizados para el control de los síntomas de esta entidad son la levodopa y los agonistas dopaminérgicos. Diversos estudios de tomografía de emisión de positrones (PET) con 18F-fluorodopa y DAT-scan realizados en pacientes tratados han mostrado, que tras 5 años dde tratamiento, la actividad dopa-descarboxilasa y del transportador de dopamina, fue mayor en los pa...

  15. Imágenes en sísmica pasiva por migración interferométrica: aplicación para microsismicidad inducida por fracturamiento hidráulico

    OpenAIRE

    Arenas Mora, John Henry

    2013-01-01

    En este trabajo se intenta demostrar la aplicabilidad del concepto de migración interferométrica para la generación de imagen sísmica a partir de registros microsísmicos. El objetivo es indagar sobre el uso de estos registros para la síntesis de la reflectividad del medio. Se realizan dos simulaciones utilizando el código de modelamiento de ecuación de onda en diferencias finitas llamado FDELMODC. Estas se configuran con fuentes profundas que pretenden emular los eventos inducidos en un fract...

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Spectrins in axonal cytoskeletons: Dynamics revealed by extensions and fluctuations

    Science.gov (United States)

    Lai, Lipeng; Cao, Jianshu

    2014-07-01

    The macroscopic properties, the properties of individual components, and how those components interact with each other are three important aspects of a composited structure. An understanding of the interplay between them is essential in the study of complex systems. Using axonal cytoskeleton as an example system, here we perform a theoretical study of slender structures that can be coarse-grained as a simple smooth three-dimensional curve. We first present a generic model for such systems based on the fundamental theorem of curves. We use this generic model to demonstrate the applicability of the well-known worm-like chain (WLC) model to the network level and investigate the situation when the system is stretched by strong forces (weakly bending limit). We specifically studied recent experimental observations that revealed the hitherto unknown periodic cytoskeleton structure of axons and measured the longitudinal fluctuations. Instead of focusing on single molecules, we apply analytical results from the WLC model to both single molecule and network levels and focus on the relations between extensions and fluctuations. We show how this approach introduces constraints to possible local dynamics of the spectrin tetramers in the axonal cytoskeleton and finally suggests simple but self-consistent dynamics of spectrins in which the spectrins in one spatial period of axons fluctuate in-sync.

  1. 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

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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

    the soma or a very proximal dendrite. L-ALPs were devoid of MAP2a/b immunoreactivity. Some of these L-ALPs projected through the lesion and formed bouton-like swellings. These results suggest that proximally axotomized spinal interneurons have the potential to form new connections via de novo axons...

  10. 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. PMID:25697845

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

    Directory of Open Access Journals (Sweden)

    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.

  12. FMRP-Mediated Axonal Delivery of miR-181d Regulates Axon Elongation by Locally Targeting Map1b and Calm1

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2015-12-01

    Full Text Available Subcellular targeting and local translation of mRNAs are critical for axon development. However, the precise local control of mRNA translation requires investigation. We report that the Fmr1-encoded protein, FMRP-mediated axonal delivery of miR-181d negatively regulates axon elongation by locally targeting the transcripts of MAP1B (Map1b and calmodulin (Calm1 in primary sensory neurons. miR-181d affected the local synthesis of MAP1B and calmodulin in axons. FMRP was associated with miR-181d, Map1b, and Calm1. Both FMRP deficiency in Fmr1I304N mice and Fmr1 knockdown impeded the axonal delivery of miR-181d, Map1b, and Calm1 and reduced the protein levels of MAP1B and calmodulin in axons. Furthermore, nerve growth factor (NGF induced Map1b and Calm1 release from FMRP and miR-181d-repressing granules, thereby promoting axon elongation. Both miR-181d overexpression and FMRP knockdown impaired NGF-induced axon elongation. Our study reveals a mechanism for the local regulation of translation by miR-181d and FMRP during axon development.

  13. Alterations of mitochondrial dynamics allow retrograde propagation of locally initiated axonal insults.

    Science.gov (United States)

    Lassus, Benjamin; Magifico, Sebastien; Pignon, Sandra; Belenguer, Pascale; Miquel, Marie-Christine; Peyrin, Jean-Michel

    2016-01-01

    In chronic neurodegenerative syndromes, neurons progressively die through a generalized retraction pattern triggering retrograde axonal degeneration toward the cell bodies, which molecular mechanisms remain elusive. Recent observations suggest that direct activation of pro-apoptotic signaling in axons triggers local degenerative events associated with early alteration of axonal mitochondrial dynamics. This raises the question of the role of mitochondrial dynamics on both axonal vulnerability stress and their implication in the spreading of damages toward unchallenged parts of the neuron. Here, using microfluidic chambers, we assessed the consequences of interfering with OPA1 and DRP1 proteins on axonal degeneration induced by local application of rotenone. We found that pharmacological inhibition of mitochondrial fission prevented axonal damage induced by rotenone, in low glucose conditions. While alteration of mitochondrial dynamics per se did not lead to spontaneous axonal degeneration, it dramatically enhanced axonal vulnerability to rotenone, which had no effect in normal glucose conditions, and promoted retrograde spreading of axonal degeneration toward the cell body. Altogether, our results suggest a mitochondrial priming effect in axons as a key process of axonal degeneration. In the context of neurodegenerative diseases, like Parkinson's and Alzheimer's, mitochondria fragmentation could hasten neuronal death and initiate spatial dispersion of locally induced degenerative events. PMID:27604820

  14. 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.

  15. 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

  16. 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.

  17. ¿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.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Missed connections: photoreceptor axon seeks target neuron for synaptogenesis.

    Science.gov (United States)

    Astigarraga, Sergio; Hofmeyer, Kerstin; Treisman, Jessica E

    2010-08-01

    Extending axons must choose the appropriate synaptic target cells in order to assemble functional neural circuitry. The axons of the Drosophila color-sensitive photoreceptors R7 and R8 project as a single fascicle from each ommatidium, but their terminals are segregated into distinct layers within their target region. Recent studies have begun to reveal the molecular mechanisms that establish this projection pattern. Both homophilic adhesion molecules and specific ligand-receptor interactions make important contributions to stabilizing R7 and R8 terminals in the appropriate target layers. These cell recognition molecules are regulated by the same transcription factors that control R7 and R8 cell fates. Autocrine and repulsive signaling mechanisms prevent photoreceptor terminals from encroaching on their neighbors, preserving the spatial resolution of visual information. PMID:20434326

  1. Estimating neuronal connectivity from axonal and dendritic density fields

    Directory of Open Access Journals (Sweden)

    Jaap evan Pelt

    2013-11-01

    Full Text Available Neurons innervate space by extending axonal and dendritic arborizations. When axons and dendrites come in close proximity of each other, synapses between neurons can be formed. Neurons vary greatly in their morphologies and synaptic connections with other neurons. The size and shape of the arborizations determine the way neurons innervate space. A neuron may therefore be characterized by the spatial distribution of its axonal and dendritic 'mass'. A population mean 'mass' density field of a particular neuron type can be obtained by averaging over the individual variations in neuron geometries. Connectivity in terms of candidate synaptic contacts between neurons can be determined directly on the basis of their arborizations but also indirectly on the basis of their density fields. To decide when a candidate synapse can be formed, we previously developed a criterion defining that axonal and dendritic line pieces should cross in 3D and have an orthogonal distance less than a threshold value. In this paper, we developed new methodology for applying this criterion to density fields. We show that estimates of the number of contacts between neuron pairs calculated from their density fields are fully consistent with the number of contacts calculated from the actual arborizations. However, the estimation of the connection probability and the expected number of contacts per connection cannot be calculated directly from density fields, because density fields do not carry anymore the correlative structure in the spatial distribution of synaptic contacts. Alternatively, these two connectivity measures can be estimated from the expected number of contacts by using empirical mapping functions. The neurons used for the validation studies were generated by our neuron simulator NETMORPH. An example is given of the estimation of average connectivity and Euclidean pre- and postsynaptic distance distributions in a network of neurons represented by their population

  2. Bazooka mediates secondary axon morphology in Drosophila brain lineages

    OpenAIRE

    Hartenstein Volker; Spindler Shana R

    2011-01-01

    Abstract In the Drosophila brain, neural lineages project bundled axon tracts into a central neuropile. Each lineage exhibits a stereotypical branching pattern and trajectory, which distinguish it from other lineages. In this study, we used a multilineage approach to explore the neural function of the Par-complex member Par3/Bazooka in vivo. Drosophila bazooka is expressed in post-mitotic neurons of the larval brain and localizes within neurons in a lineage-dependent manner. The fact that mul...

  3. Tau phosphorylation affects its axonal transport and degradation

    OpenAIRE

    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 ...

  4. Adult motor axons preferentially reinnervate predegenerated muscle nerve

    OpenAIRE

    M. Abdullah; O'Daly, A.; A Vyas; Rohde, C.; Brushart, T.M.

    2013-01-01

    Preferential motor reinnervation (PMR) is the tendency for motor axons regenerating after repair of mixed nerve to reinnervate muscle nerve and/or muscle rather than cutaneous nerve or skin. PMR may occur in response to the peripheral nerve pathway alone in juvenile rats (Brushart, 1993; Redett et al., 2005), yet the ability to identify and respond to specific pathway markers is reportedly lost in adults (Uschold et al., 2007). The experiments reported here evaluate the relative roles of path...

  5. 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.

  6. Axonal Transport Impairment in Chemotherapy-Induced Peripheral Neuropathy

    Directory of Open Access Journals (Sweden)

    Gabriella Nicolini

    2015-08-01

    Full Text Available Chemotherapy-Induced Peripheral Neuropathy (CIPN is a dose-limiting side effect of several antineoplastic drugs which significantly reduces patients’ quality of life. Although different molecular mechanisms have been investigated, CIPN pathobiology has not been clarified yet. It has largely been recognized that Dorsal Root Ganglia are the main targets of chemotherapy and that the longest nerves are the most damaged, together with fast axonal transport. Indeed, this bidirectional cargo-specific transport has a pivotal role in neuronal function and its impairment is involved in several neurodegenerative and neurodevelopmental diseases. Literature data demonstrate that, despite different mechanisms of action, all antineoplastic agents impair the axonal trafficking to some extent and the severity of the neuropathy correlates with the degree of damage on this bidirectional transport. In this paper, we will examine the effect of the main old and new chemotherapeutic drug categories on axonal transport, with the aim of clarifying their potential mechanisms of action, and, if possible, of identifying neuroprotective strategies, based on the knowledge of the alterations induced by each drugs.

  7. EEG functional connectivity, axon delays and white matter disease

    Science.gov (United States)

    Nunez, Paul L.; Srinivasan, Ramesh; Fields, R. Douglas

    2016-01-01

    Objective Both structural and functional brain connectivities are closely linked to white matter disease. We discuss several such links of potential interest to neurologists, neurosurgeons, radiologists, and non-clinical neuroscientists. Methods Treatment of brains as genuine complex systems suggests major emphasis on the multi-scale nature of brain connectivity and dynamic behavior. Cross-scale interactions of local, regional, and global networks are apparently responsible for much of EEG's oscillatory behaviors. Finite axon propagation speed, often assumed to be infinite in local network models, is central to our conceptual framework. Results Myelin controls axon speed, and the synchrony of impulse traffic between distant cortical regions appears to be critical for optimal mental performance and learning. Results Several experiments suggest that axon conduction speed is plastic, thereby altering the regional and global white matter connections that facilitate binding of remote local networks. Conclusions Combined EEG and high resolution EEG can provide distinct multi-scale estimates of functional connectivity in both healthy and diseased brains with measures like frequency and phase spectra, covariance, and coherence. Significance White matter disease may profoundly disrupt normal EEG coherence patterns, but currently these kinds of studies are rare in scientific labs and essentially missing from clinical environments. PMID:24815984

  8. Dysregulated axonal RNA translation in amyotrophic lateral sclerosis.

    Science.gov (United States)

    Yasuda, Kyota; Mili, Stavroula

    2016-09-01

    Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron disease that has been associated with a diverse array of genetic changes. Prominent among these are mutations in RNA-binding proteins (RBPs) or repeat expansions that give rise to toxic RNA species. RBPs are additionally central components of pathologic aggregates that constitute a disease hallmark, suggesting that dysregulation of RNA metabolism underlies disease progression. In the context of neuronal physiology, transport of RNAs and localized RNA translation in axons are fundamental to neuronal survival and function. Several lines of evidence suggest that axonal RNA translation is a central process perturbed by various pathogenic events associated with ALS. Dysregulated translation of specific RNA groups could underlie feedback effects that connect and reinforce disease manifestations. Among such candidates are RNAs encoding proteins involved in the regulation of microtubule dynamics. Further understanding of axonally dysregulated RNA targets and of the feedback mechanisms they induce could provide useful therapeutic insights. WIREs RNA 2016, 7:589-603. doi: 10.1002/wrna.1352 For further resources related to this article, please visit the WIREs website. PMID:27038103

  9. 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.

  10. Retinal glia promote dorsal root ganglion axon regeneration.

    Directory of Open Access Journals (Sweden)

    Barbara Lorber

    Full Text Available Axon regeneration in the adult central nervous system (CNS is limited by several factors including a lack of neurotrophic support. Recent studies have shown that glia from the adult rat CNS, specifically retinal astrocytes and Müller glia, can promote regeneration of retinal ganglion cell axons. In the present study we investigated whether retinal glia also exert a growth promoting effect outside the visual system. We found that retinal glial conditioned medium significantly enhanced neurite growth and branching of adult rat dorsal root ganglion neurons (DRG in culture. Furthermore, transplantation of retinal glia significantly enhanced regeneration of DRG axons past the dorsal root entry zone after root crush in adult rats. To identify the factors that mediate the growth promoting effects of retinal glia, mass spectrometric analysis of retinal glial conditioned medium was performed. Apolipoprotein E and secreted protein acidic and rich in cysteine (SPARC were found to be present in high abundance, a finding further confirmed by western blotting. Inhibition of Apolipoprotein E and SPARC significantly reduced the neuritogenic effects of retinal glial conditioned medium on DRG in culture, suggesting that Apolipoprotein E and SPARC are the major mediators of this regenerative response.

  11. 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.

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

    Science.gov (United States)

    Iwai, Yuta; Shibuya, Kazumoto; Misawa, Sonoko; Sekiguchi, Yukari; Watanabe, Keisuke; Amino, Hiroshi; Kuwabara, Satoshi

    2016-01-01

    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 CMAP (> 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. PMID:27383069

  13. 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

    " pockets. The total number of axons in the sural nerve was unchanged, but a greater proportion was unmyelinated. In addition, we observed large-diameter axons that were in a 1:1 relationship with Schwann cells, surrounded by a basal lamina but not myelinated. There was no evidence of DRG or Schwann cell...

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

    OpenAIRE

    Daniel Francisco Arencibia Arrebola; Luis Alfredo Rosario Fernández; Yolanda Emilia Suárez Fernández; Livan Delgado Roche; Juan Francisco Infante Bourzac

    2011-01-01

    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 determ...

  15. 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.

  16. Irregular geometries in normal unmyelinated axons: a 3D serial EM analysis.

    Science.gov (United States)

    Greenberg, M M; Leitao, C; Trogadis, J; Stevens, J K

    1990-12-01

    Axons have generally been represented as straight cylinders. It is not at all uncommon for anatomists to take single cross-sections of an axonal bundle, and from the axonal diameter compute expected conduction velocities. This assumes that each cross-section represents a slice through a perfect cylinder. We have examined the three-dimensional geometry of 98 central and peripheral unmyelinated axons, using computer-assisted serial electron microscopy. These reconstructions reveal that virtually all unmyelinated axons have highly irregular axial shapes consisting of periodic varicosities. The varicosities were, without exception, filled with membranous organelles frequently including mitochondria, and have obligatory volumes similar to that described in other neurites. The mitochondria make contact with microtubules, while the other membraneous organelles were frequently found free floating in the cytoplasm. We conclude that unmyelinated axons are fundamentally varicose structures created by the presence of organelles, and that an axon's calibre is dynamic in both space and time. These irregular axonal geometries raise serious doubts about standard two dimensional morphometric analysis and suggest that electrical properties may be more heterogeneous than expected from single section data. These results also suggest that the total number of microtubules contained in an axon, rather than its single section diameter, may prove to be a more accurate predictor of properties such as conduction velocity. Finally, these results offer an explanation for a number of pathological changes that have been described in unmyelinated axons. PMID:2292722

  17. 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.

  18. 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

  19. Soluble axoplasm enriched from injured CNS axons reveals the early modulation of the actin cytoskeleton.

    Directory of Open Access Journals (Sweden)

    Patrick Garland

    Full Text Available Axon injury and degeneration is a common consequence of diverse neurological conditions including multiple sclerosis, traumatic brain injury and spinal cord injury. The molecular events underlying axon degeneration are poorly understood. We have developed a novel method to enrich for axoplasm from rodent optic nerve and characterised the early events in Wallerian degeneration using an unbiased proteomics screen. Our detergent-free method draws axoplasm into a dehydrated hydrogel of the polymer poly(2-hydroxyethyl methacrylate, which is then recovered using centrifugation. This technique is able to recover axonal proteins and significantly deplete glial contamination as confirmed by immunoblotting. We have used iTRAQ to compare axoplasm-enriched samples from naïve vs injured optic nerves, which has revealed a pronounced modulation of proteins associated with the actin cytoskeleton. To confirm the modulation of the actin cytoskeleton in injured axons we focused on the RhoA pathway. Western blotting revealed an augmentation of RhoA and phosphorylated cofilin in axoplasm-enriched samples from injured optic nerve. To investigate the localisation of these components of the RhoA pathway in injured axons we transected axons of primary hippocampal neurons in vitro. We observed an early modulation of filamentous actin with a concomitant redistribution of phosphorylated cofilin in injured axons. At later time-points, RhoA is found to accumulate in axonal swellings and also colocalises with filamentous actin. The actin cytoskeleton is a known sensor of cell viability across multiple eukaryotes, and our results suggest a similar role for the actin cytoskeleton following axon injury. In agreement with other reports, our data also highlights the role of the RhoA pathway in axon degeneration. These findings highlight a previously unexplored area of axon biology, which may open novel avenues to prevent axon degeneration. Our method for isolating CNS axoplasm

  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. Sincronización de la ovulación y el ciclo inducido por el efecto "macho" mediante la administración de progesterona por vía intravaginal en cabras en período de anestro estacional

    OpenAIRE

    Mogedas Moreno, María

    2016-01-01

    Algunos de los métodos alternativos a los tratamientos hormonales clásicos utilizando progestágenos y eCG, para la inducción y sincronización del celo y la ovulación, unido a la inseminación artificial (IA) a tiempo fijo en ganado caprino, están basados como el IMA.PRO2® en el estímulo por la presencia de los machos (efecto macho) y la sincronización de la ovulación inducida mediante prostaglandina F2α o sus análogos. En estos métodos, la administración de una dosis baja de progesterona o pro...

  2. 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.

  3. 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.

  4. Disruption of Cnp1 uncouples oligodendroglial functions in axonal support and myelination.

    Science.gov (United States)

    Lappe-Siefke, Corinna; Goebbels, Sandra; Gravel, Michel; Nicksch, Eva; Lee, John; Braun, Peter E; Griffiths, Ian R; Nave, Klaus-Armin

    2003-03-01

    Myelination of axons by oligodendrocytes enables rapid impulse propagation in the central nervous system. But long-term interactions between axons and their myelin sheaths are poorly understood. Here we show that Cnp1, which encodes 2',3'-cyclic nucleotide phosphodiesterase in oligodendrocytes, is essential for axonal survival but not for myelin assembly. In the absence of glial cyclic nucleotide phosphodiesterase, mice developed axonal swellings and neurodegeneration throughout the brain, leading to hydrocephalus and premature death. But, in contrast to previously studied myelin mutants, the ultrastructure, periodicity and physical stability of myelin were not altered in these mice. Genetically, the chief function of glia in supporting axonal integrity can thus be completely uncoupled from its function in maintaining compact myelin. Oligodendrocyte dysfunction, such as that in multiple sclerosis lesions, may suffice to cause secondary axonal loss. PMID:12590258

  5. X11/Mint Genes Control Polarized Localization of Axonal Membrane Proteins in Vivo

    OpenAIRE

    Garrett G Gross; Lone, G. Mohiddin; Leung, Lok Kwan; Hartenstein, Volker; Guo, Ming

    2013-01-01

    Mislocalization of axonal proteins can result in misassembly and/or miswiring of neural circuits, causing disease. To date, only a handful of genes that control polarized localization of axonal membrane proteins have been identified. Here we report that Drosophila X11/Mint proteins are required for targeting several proteins, including human amyloid precursor protein (APP) and Drosophila APP-like protein (APPL), to axonal membranes and for their exclusion from dendrites of the mushroom body i...

  6. Directional specificity and patterning of sensory axons in trigeminal ganglion–whisker pad cocultures

    OpenAIRE

    Gunhan-Agar, Emine; Haeberle, Adam; Erzurumlu, Reha S.

    2000-01-01

    In the rodent trigeminal pathway, trigeminal axons invade the developing whisker pad from a caudal to rostral direction. We investigated directional specificity of embryonic day (E). 15 rat trigeminal axons within this peripheral target field using explant cocultures. E15 trigeminal axons readily grow into the same age whisker pad explants and form follicle-related patterns along a caudal to rostral direction. They also can grow into this target from its lateral aspects. In contrast, they are...

  7. Differential Effects of NGF and NT-3 on Embryonic Trigeminal Axon Growth Patterns

    OpenAIRE

    Ulupinar, Emel; Jacquin, Mark F.; Erzurumlu, Reha S.

    2000-01-01

    We examined the effects of neurotrophins nerve growth factor (NGF) and neurotrophin-3 (NT-3) on trigeminal axon growth patterns. Embryonic (E13–15) wholemount explants of the rat trigeminal pathway including the whisker pads, trigeminal ganglia, and brainstem were cultured in serum-free medium (SFM) or SFM supplemented with NGF or NT-3 for 3 days. Trigeminal axon growth patterns were analyzed with the use of lipophilic tracer DiI. In wholemount cultures grown in SFM, trigeminal axon projectio...

  8. Actin turnover is required to prevent axon retraction driven by endogenous actomyosin contractility

    OpenAIRE

    Gallo, Gianluca; Yee, Hal F.; Letourneau, Paul C.

    2002-01-01

    Growth cone motility and guidance depend on the dynamic reorganization of filamentous actin (F-actin). In the growth cone, F-actin undergoes turnover, which is the exchange of actin subunits from existing filaments. However, the function of F-actin turnover is not clear. We used jasplakinolide (jasp), a cell-permeable macrocyclic peptide that inhibits F-actin turnover, to study the role of F-actin turnover in axon extension. Treatment with jasp caused axon retraction, demonstrating that axon ...

  9. N-Propionylmannosamine stimulates axonal elongation in a murine model of sciatic nerve injury

    Institute of Scientific and Technical Information of China (English)

    Christian Witzel; Werner Reutter; G Bjrn Stark; Georgios Koulaxouzidis

    2015-01-01

    Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modiifed 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 inlfuence of systemic ManNProp application using a speciifc in vivo mouse model. Using mice expressing axonal lfuorescent proteins, we quantiifed 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 lfuorescent 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 signiifcantly 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 glycoen-gineering of the N-acyl side chain of sialic acid might be a promising approach for improving peripheral nerve regeneration.

  10. Thiazolidinediones promote axonal growth through the activation of the JNK pathway.

    Directory of Open Access Journals (Sweden)

    Rodrigo A Quintanilla

    Full Text Available 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.

  11. 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......, little is known of its importance in the control of axon guidance. In a screen of prolyl 4-hydroxylase (P4H) mutants, we found that genetic removal of a specific P4H subunit, DPY-18, causes dramatic defects in C. elegans neuroanatomy. In dpy-18 mutant animals, the axons of specific ventral nerve cord...

  12. 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.

  13. 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

  14. Studying Axonal Regeneration by Laser Microsurgery and High-Resolution Videomicroscopy.

    Science.gov (United States)

    Xiao, Yan; López-Schier, Hernán

    2016-01-01

    Heterogeneous and unpredictable environmental insult, disease, or trauma can affect the integrity and function of neuronal circuits, leading to irreversible neural dysfunction. The peripheral nervous system can robustly regenerate axons after damage to recover the capacity to transmit sensory information to the brain. The mechanisms that allow axonal repair remain incompletely understood. Here we present a preparation in zebrafish that combines laser microsurgery of sensory axons and videomicroscopy of neurons in multicolor transgenic specimens. This simple protocol allows controlled damage of axons and dynamic high-resolution visualization and quantification of repair. PMID:27464814

  15. 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

    2015-05-01

    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.

  16. Biomarker evidence of axonal injury in neuroasymptomatic HIV-1 patients.

    Directory of Open Access Journals (Sweden)

    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. Excitability properties of motor axons in adults with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Cliff S. Klein

    2015-06-01

    Full Text Available Cerebral Palsy (CP is a permanent disorder caused by a lesion to the developing brain that significantly impairs motor function. The neurophysiological mechanisms underlying motor impairment are not well understood. Specifically, few have addressed whether motoneuron or peripheral axon properties are altered in CP, even though disruption of descending inputs to the spinal cord may cause them to change. In the present study, we have compared nerve excitability properties in seven adults with CP and fourteen healthy controls using threshold tracking techniques by stimulating the median nerve at the wrist and recording the compound muscle action potential (CMAP over the abductor pollicis brevis. The excitability properties in the CP subjects were found to be abnormal. Early and late depolarizing and hyperpolarizing threshold electrotonus was significantly larger (i.e., fanning out, and resting current-threshold (I/V slope was smaller, in CP compared to control. In addition resting threshold and rheobase tended to be larger in CP. According to a modeling analysis of the data, an increase in leakage current under or through the myelin sheath, i.e., the Barrett-Barrett conductance (GBB, combined with a slight hyperpolarization of the resting membrane potential, best explained the group differences in excitability properties. There was a trend for those with greater impairment in gross motor function to have more abnormal axon properties. The findings indicate plasticity of motor axon properties far removed from the site of the lesion. We suspect that this plasticity is caused by disruption of descending inputs to the motoneurons at an early age around the time of their injury.

  18. 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...

  19. Gogo receptor contributes to retinotopic map formation and prevents R1-6 photoreceptor axon bundling.

    Directory of Open Access Journals (Sweden)

    Irina Hein

    Full Text Available BACKGROUND: Topographic maps form the basis of neural processing in sensory systems of both vertebrate and invertebrate species. In the Drosophila visual system, neighboring R1-R6 photoreceptor axons innervate adjacent positions in the first optic ganglion, the lamina, and thereby represent visual space as a continuous map in the brain. The mechanisms responsible for the establishment of retinotopic maps remain incompletely understood. RESULTS: Here, we show that the receptor Golden goal (Gogo is required for R axon lamina targeting and cartridge elongation in a partially redundant fashion with local guidance cues provided by neighboring axons. Loss of function of Gogo in large clones of R axons results in aberrant R1-R6 fascicle spacing. Gogo affects target cartridge selection only indirectly as a consequence of the disordered lamina map. Interestingly, small clones of gogo deficient R axons perfectly integrate into a proper retinotopic map suggesting that surrounding R axons of the same or neighboring fascicles provide complementary spatial guidance. Using single photoreceptor type rescue, we show that Gogo expression exclusively in R8 cells is sufficient to mediate targeting of all photoreceptor types in the lamina. Upon lamina targeting and cartridge selection, R axons elongate within their individual cartridges. Interestingly, here Gogo prevents bundling of extending R1-6 axons. CONCLUSION: Taken together, we propose that Gogo contributes to retinotopic map formation in the Drosophila lamina by controlling the distribution of R1-R6 axon fascicles. In a later developmental step, the regular position of R1-R6 axons along the lamina plexus is crucial for target cartridge selection. During cartridge elongation, Gogo allows R1-R6 axons to extend centrally in the lamina cartridge.

  20. 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

  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. 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.

  3. Bazooka mediates secondary axon morphology in Drosophila brain lineages

    Directory of Open Access Journals (Sweden)

    Hartenstein Volker

    2011-04-01

    Full Text Available Abstract In the Drosophila brain, neural lineages project bundled axon tracts into a central neuropile. Each lineage exhibits a stereotypical branching pattern and trajectory, which distinguish it from other lineages. In this study, we used a multilineage approach to explore the neural function of the Par-complex member Par3/Bazooka in vivo. Drosophila bazooka is expressed in post-mitotic neurons of the larval brain and localizes within neurons in a lineage-dependent manner. The fact that multiple GAL4 drivers have been mapped to several lineages of the Drosophila brain enables investigation of the role of Bazooka from larval to adult stages Bazooka loss-of-function (LOF clones had abnormal morphologies, including aberrant pathway choice of ventral projection neurons in the BAla1 lineage, ectopic branching in the DALv2 and BAmv1 lineages, and excess BLD5 lineage axon projections in the optic medulla. Exogenous expression of Bazooka protein in BAla1 neurons rescued defective guidance, supporting an intrinsic requirement for Bazooka in the post-mitotic neuron. Elimination of the Par-complex member Par6 recapitulated Bazooka phenotypes in some but not all lineages, suggesting that the Par complex functions in a lineage-dependent manner, and that Bazooka may act independently in some lineages. Importantly, this study highlights the potential of using a multilineage approach when studying gene function during neural development in Drosophila.

  4. Bazooka mediates secondary axon morphology in Drosophila brain lineages.

    Science.gov (United States)

    Spindler, Shana R; Hartenstein, Volker

    2011-01-01

    In the Drosophila brain, neural lineages project bundled axon tracts into a central neuropile. Each lineage exhibits a stereotypical branching pattern and trajectory, which distinguish it from other lineages. In this study, we used a multilineage approach to explore the neural function of the Par-complex member Par3/Bazooka in vivo. Drosophila bazooka is expressed in post-mitotic neurons of the larval brain and localizes within neurons in a lineage-dependent manner. The fact that multiple GAL4 drivers have been mapped to several lineages of the Drosophila brain enables investigation of the role of Bazooka from larval to adult stages Bazooka loss-of-function (LOF) clones had abnormal morphologies, including aberrant pathway choice of ventral projection neurons in the BAla1 lineage, ectopic branching in the DALv2 and BAmv1 lineages, and excess BLD5 lineage axon projections in the optic medulla. Exogenous expression of Bazooka protein in BAla1 neurons rescued defective guidance, supporting an intrinsic requirement for Bazooka in the post-mitotic neuron. Elimination of the Par-complex member Par6 recapitulated Bazooka phenotypes in some but not all lineages, suggesting that the Par complex functions in a lineage-dependent manner, and that Bazooka may act independently in some lineages. Importantly, this study highlights the potential of using a multilineage approach when studying gene function during neural development in Drosophila. PMID:21524279

  5. 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.

  6. 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.

  7. An ex vivo laser-induced spinal cord injury model to assess mechanisms of axonal degeneration in real-time.

    Science.gov (United States)

    Okada, Starlyn L M; Stivers, Nicole S; Stys, Peter K; Stirling, David P

    2014-01-01

    Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular

  8. 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.

  9. 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.

  10. Axon-somatic back-propagation in detailed models of spinal alpha motoneurons

    Directory of Open Access Journals (Sweden)

    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.

  11. Integration of shallow gradients of Shh and Netrin-1 guides commissural axons.

    Directory of Open Access Journals (Sweden)

    Tyler F W Sloan

    2015-03-01

    Full Text Available 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.

  12. 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.

  13. C. elegans: a new model organism for studies of axon regeneration

    OpenAIRE

    Ghosh-Roy, Anindya; Chisholm, Andrew D.

    2010-01-01

    Axonal regeneration in C. elegans was first reported five years ago. Individual GFP-labeled axons can be severed using laser microsurgery and their regrowth followed in vivo. Several neuron types display robust regrowth after injury, including motor and sensory neurons. The small size and transparency of C. elegans make possible large-scale genetic and pharmacological screens for regeneration phenotypes.

  14. Distribution of neurofilaments in myelinated axons of the optic nerve of goldfish (Carassius auratus L.).

    Science.gov (United States)

    Matheson, D F; Diocee, M S; Roots, B I

    1980-11-01

    Neurofilaments were counted in myelinated axons of the optic nerve of goldfish which were acclimated to 5 degrees and 25 degrees C. The number of neurofilaments increases markedly with increasing axonal size; axons of less than 0.1 micrometer 2 in area contain between 25 and 60 neurofilaments, while in the larger axons of area greater than 1.0 micrometer 2 there are approximately 190. The densities of the neurofilaments in the small axons are noticeably higher than in the larger ones (507 and 160, respectively). A variety of fixation procedures i.e. osmium tetroxide (OsO4) in phosphate buffer, glutaraldehyde (4%) in phosphate buffer or in ethyleneglycol-bis-(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) and piperazine-N-N'-bis-(2-ethanesulphonic acid) (PIPES) and post-fixed with OsO4 had no effect on the numbers of neurofilaments relative to the size of axon. The anaesthetic MS-222 (tricaine methanesulphonate) likewise had no effect on the numbers of neurofilaments. It is proposed that temperature acclimation alters the axon diameter concomitant with an alteration in the number of neurofilaments to fit the new diameter of the axons. PMID:6253602

  15. N-docosahexaenoylethanolamine regulates Hedgehog signaling and promotes growth of cortical axons

    Directory of Open Access Journals (Sweden)

    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.

  16. 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.

  17. CD8+ T cells cause disability and axon loss in a mouse model of multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Chandra Deb

    Full Text Available BACKGROUND: The objective of this study was to test the hypothesis that CD8+ T cells directly mediate motor disability and axon injury in the demyelinated central nervous system. We have previously observed that genetic deletion of the CD8+ T cell effector molecule perforin leads to preservation of motor function and preservation of spinal axons in chronically demyelinated mice. METHODOLOGY/PRINCIPAL FINDINGS: To determine if CD8+ T cells are necessary and sufficient to directly injure demyelinated axons, we adoptively transferred purified perforin-competent CD8+ spinal cord-infiltrating T cells into profoundly demyelinated but functionally preserved perforin-deficient host mice. Transfer of CD8+ spinal cord-infiltrating T cells rapidly and irreversibly impaired motor function, disrupted spinal cord motor conduction, and reduced the number of medium- and large-caliber spinal axons. Likewise, immunodepletion of CD8+ T cells from chronically demyelinated wildtype mice preserved motor function and limited axon loss without altering other disease parameters. CONCLUSIONS/SIGNIFICANCE: In multiple sclerosis patients, CD8+ T cells outnumber CD4+ T cells in active lesions and the number of CD8+ T cells correlates with the extent of ongoing axon injury and functional disability. Our findings suggest that CD8+ T cells may directly injure demyelinated axons and are therefore a viable therapeutic target to protect axons and motor function in patients with multiple sclerosis.

  18. A model of fasciculation and sorting in mixed populations of axons

    CERN Document Server

    Chaudhuri, Debasish; Zapotocky, Martin

    2010-01-01

    We extend a recently proposed model (Chaudhuri et al., EPL 87, 20003 (2009)), aiming to describe the formation of fascicles of axons during neural development. The growing axons are represented as paths of interacting directed random walkers in two spatial dimensions. To mimic turnover of axons, whole paths are removed and new walkers are injected with specified rates. In the simplest version of the model, we use strongly adhesive inter-axon interactions that are identical for all pairs of axons. We generalize the model to interactions of finite strengths and to multiple types of axons with type-specific interactions. The dynamic steady state is characterized by the position-dependent distribution of fascicle sizes. With distance in the direction of axon growth, the mean fascicle size and emergent time scales grow monotonically, while the degree of sorting of fascicles by axon type has a maximum at a finite distance. To understand the emergence of slow time scales, we develop an analytical framework to analyz...

  19. Fast and simplified mapping of mean axon diameter using temporal diffusion spectroscopy.

    Science.gov (United States)

    Xu, Junzhong; Li, Hua; Li, Ke; Harkins, Kevin D; Jiang, Xiaoyu; Xie, Jingping; Kang, Hakmook; Dortch, Richard D; Anderson, Adam W; Does, Mark D; Gore, John C

    2016-04-01

    Mapping axon diameter is of interest for the potential diagnosis and monitoring of various neuronal pathologies. Advanced diffusion-weighted MRI methods have been developed to measure mean axon diameters non-invasively, but suffer major drawbacks that prevent their direct translation into clinical practice, such as complex non-linear data fitting and, more importantly, long scanning times that are usually not tolerable for most human subjects. In the current study, temporal diffusion spectroscopy using oscillating diffusion gradients was used to measure mean axon diameters with high sensitivity to small axons in the central nervous system. Axon diameters have been found to be correlated with a novel metric, DDR⊥ (the rate of dispersion of the perpendicular diffusion coefficient with gradient frequency), which is a model-free quantity that does not require complex data analyses and can be obtained from two diffusion coefficient measurements in clinically relevant times with conventional MRI machines. A comprehensive investigation including computer simulations and animal experiments ex vivo showed that measurements of DDR⊥ agree closely with histological data. In humans in vivo, DDR⊥ was also found to correlate well with reported mean axon diameters in human corpus callosum, and the total scan time was only about 8 min. In conclusion, DDR⊥ may have potential to serve as a fast, simple and model-free approach to map the mean axon diameter of white matter in clinics for assessing axon diameter changes. PMID:27077155

  20. A developmental timing switch promotes axon outgrowth independent of known guidance receptors.

    Directory of Open Access Journals (Sweden)

    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.

  1. Blast overpressure induced axonal injury changes in rat brainstem and spinal cord

    Directory of Open Access Journals (Sweden)

    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.

  2. 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.

  3. 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.

  4. RIPK1 mediates axonal degeneration by promoting inflammation and necroptosis in ALS.

    Science.gov (United States)

    Ito, Yasushi; Ofengeim, Dimitry; Najafov, Ayaz; Das, Sudeshna; Saberi, Shahram; Li, Ying; Hitomi, Junichi; Zhu, Hong; Chen, Hongbo; Mayo, Lior; Geng, Jiefei; Amin, Palak; DeWitt, Judy Park; Mookhtiar, Adnan Kasim; Florez, Marcus; Ouchida, Amanda Tomie; Fan, Jian-bing; Pasparakis, Manolis; Kelliher, Michelle A; Ravits, John; Yuan, Junying

    2016-08-01

    Mutations in the optineurin (OPTN) gene have been implicated in both familial and sporadic amyotrophic lateral sclerosis (ALS). However, the role of this protein in the central nervous system (CNS) and how it may contribute to ALS pathology are unclear. Here, we found that optineurin actively suppressed receptor-interacting kinase 1 (RIPK1)-dependent signaling by regulating its turnover. Loss of OPTN led to progressive dysmyelination and axonal degeneration through engagement of necroptotic machinery in the CNS, including RIPK1, RIPK3, and mixed lineage kinase domain-like protein (MLKL). Furthermore, RIPK1- and RIPK3-mediated axonal pathology was commonly observed in SOD1(G93A) transgenic mice and pathological samples from human ALS patients. Thus, RIPK1 and RIPK3 play a critical role in mediating progressive axonal degeneration. Furthermore, inhibiting RIPK1 kinase may provide an axonal protective strategy for the treatment of ALS and other human degenerative diseases characterized by axonal degeneration. PMID:27493188

  5. 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

  6. Matrix metalloproteinase 2 and membrane type 1 matrix metalloproteinase co-regulate axonal outgrowth of mouse retinal ganglion cells

    DEFF Research Database (Denmark)

    Gaublomme, Djoere; Buyens, Tom; De Groef, Lies;

    2014-01-01

    , we were able to show that broad-spectrum MMP inhibition reduces axon outgrowth of mouse retinal ganglion cells (RGCs), implicating MMPs as beneficial factors in axonal regeneration. Additional studies, using more specific MMP inhibitors and MMP-deficient mice, disclosed that both MMP-2 and MT1-MMP...... mouse retinal explants. Our data indicate MMP-2 and MT1-MMP as promising axonal outgrowth-promoting molecules and show a possible link between MMP-2 and β1-integrin in axon outgrowth....

  7. The Drosophila immunoglobulin gene turtle encodes guidance molecules involved in axon pathfinding

    Directory of Open Access Journals (Sweden)

    Al-Anzi Bader

    2009-08-01

    Full Text Available Abstract Background Neuronal growth cones follow specific pathways over long distances in order to reach their appropriate targets. Research over the past 15 years has yielded a large body of information concerning the molecules that regulate this process. Some of these molecules, such as the evolutionarily conserved netrin and slit proteins, are expressed in the embryonic midline, an area of extreme importance for early axon pathfinding decisions. A general model has emerged in which netrin attracts commissural axons towards the midline while slit forces them out. However, a large number of commissural axons successfully cross the midline even in the complete absence of netrin signaling, indicating the presence of a yet unidentified midline attractant. Results The evolutionarily conserved Ig proteins encoded by the turtle/Dasm1 genes are found in Drosophila, Caenorhabditis elegans, and mammals. In Drosophila the turtle gene encodes five proteins, two of which are diffusible, that are expressed in many areas, including the vicinity of the midline. Using both molecular null alleles and transgenic expression of the different isoforms, we show that the turtle encoded proteins function as non-cell autonomous axonal attractants that promote midline crossing via a netrin-independent mechanism. turtle mutants also have either stalled or missing axon projections, while overexpression of the different turtle isoforms produces invasive neurons and branching axons that do not respect the histological divisions of the nervous system. Conclusion Our findings indicate that the turtle proteins function as axon guidance cues that promote midline attraction, axon branching, and axonal invasiveness. The latter two capabilities are required by migrating axons to explore densely packed targets.

  8. 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.

  9. Dermatitis canina por Malassezia

    Directory of Open Access Journals (Sweden)

    Rejas López, Juan

    2008-05-01

    Full Text Available La dermatitis por Malassezia en perros en generalmente una complicación a procesos alérgicos, seborreicos, presencia de pliegues, etc. aunque también se han descrito otras presentaciones, como la hipersensibilidad contra esta levadura. La demostración de la presencia de Malassesia pachydermatis se hace de manera sencilla mediante citología. El tratamiento de esta dermatitis puede ser tópico u oral.

  10. Dermatitis canina por Malassezia

    OpenAIRE

    Rejas López, Juan

    2008-01-01

    La dermatitis por Malassezia en perros en generalmente una complicación a procesos alérgicos, seborreicos, presencia de pliegues, etc. aunque también se han descrito otras presentaciones, como la hipersensibilidad contra esta levadura. La demostración de la presencia de Malassesia pachydermatis se hace de manera sencilla mediante citología. El tratamiento de esta dermatitis puede ser tópico u oral.

  11. 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.

  12. Dynamic Changes in Local Protein Synthetic Machinery in Regenerating Central Nervous System Axons after Spinal Cord Injury

    Science.gov (United States)

    Sachdeva, Rahul; Farrell, Kaitlin; McMullen, Mary-Katharine; Twiss, Jeffery L.; Houle, John D.

    2016-01-01

    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.

  13. Regional node-like membrane specializations in non-myelinated axons of rat retinal nerve fiber layer.

    Science.gov (United States)

    Hildebrand, C; Waxman, S G

    1983-01-01

    The axons in the nerve fiber layer (NFL) of the adult rat retina were examined by transmission electron microscopy. NFL axons range in size from 0.12 to about 2.0 microm, with a peak at 0.3-0.4 microm. In addition to conventional small mitochondria in the NFL axons contain some large ones, which are similar to astrocytic gliosomes. Two types of regional axon membrane specialization are found in the NFL. One of these represents portions of the initial axon segments of retinal ganglion cells. Apart from features typical for initial axon segments in general, a corona of lamelliform, villous or blunt glial processes is always present. The glial processes originate from MUller cells. The other regional axon membrane specialization consists of patches of an electron-dense subaxolemmal undercoating with associated tufts of Miller cell processes. These patches cover a varying but always limited proportion of the axon circumference and their longitudinal extent varies between 0.5 and 5.0 microm. They are clearly distinct from the initial axon segment and from the initial heminode in the optic nerve. Similar undercoated patches in the optic disc axons are apposed by astrocytic processes. It is concluded that rat NFL axons represent an example of central non-myelinated axons with distinct regional membrane specializations, which have some structural characteristics in common with nodes of Ranvier. PMID:24010160

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Diffuse axonal injury at ultra-high field MRI.

    Directory of Open Access Journals (Sweden)

    Christoph Moenninghoff

    Full Text Available Diffuse axonal injury (DAI is a specific type of traumatic brain injury caused by shearing forces leading to widespread tearing of axons and small vessels. Traumatic microbleeds (TMBs are regarded as a radiological marker for DAI. This study aims to compare DAI-associated TMBs at 3 Tesla (T and 7 T susceptibility weighted imaging (SWI to evaluate possible diagnostic benefits of ultra-high field (UHF MRI.10 study participants (4 male, 6 female, age range 20-74 years with known DAI were included. All MR exams were performed with a 3 T MR system (Magnetom Skyra and a 7 T MR research system (Magnetom 7 T, Siemens AG, Healthcare Sector, Erlangen, Germany each in combination with a 32-channel-receive coil. The average time interval between trauma and imaging was 22 months. Location and count of TMBs were independently evaluated by two neuroradiologists on 3 T and 7 T SWI images with similar and additionally increased spatial resolution at 7 T. Inter- and intraobserver reliability was assessed using the interclass correlation coefficient (ICC. Count and diameter of TMB were evaluated with Wilcoxon signed rank test.Susceptibility weighted imaging revealed a total of 485 TMBs (range 1-190, median 25 at 3 T, 584 TMBs (plus 20%, range 1-262, median 30.5 at 7 T with similar spatial resolution, and 684 TMBs (plus 41%, range 1-288, median 39.5 at 7 T with 10-times higher spatial resolution. Hemorrhagic DAI appeared significantly larger at 7 T compared to 3 T (p = 0.005. Inter- and intraobserver correlation regarding the counted TMB was high and almost equal 3 T and 7 T.7 T SWI improves the depiction of small hemorrhagic DAI compared to 3 T and may be supplementary to lower field strengths for diagnostic in inconclusive or medicolegal cases.

  19. Análisis de las fallas en transformadores causadas por la operación del pararrayos ante sobretensiones externas

    Directory of Open Access Journals (Sweden)

    Francisco Román Campos

    2011-02-01

    Full Text Available Uno de los problemas más graves que afronta el Sector Eléctrico Colombiano, es el alto índice de fallas de transformadores de distribución, que para el caso de la reglón central del país, servida por la Empresa de Energía Eléctrica de Bogotá -EEB-, significó cerca de 983 millones de pesos en el año 1987. De los análisis de fallas realizadas por la EEB, se desprende que un alto porcentaje de las mismas pueden deberse a Descargas Eléctricas Atmosféricas. El presente articulo tiene por objeto analizar este tipo de fallas y explicar mediante el concepto de los llamados "Lazos Inductivos" -que tienen su aplicación en los estudios de protección contra rayos directos en pararrayos tipo Franklin-; lo que unido a la alta resistividad del terreno, los drásticos cambios de Impedancia en el sitio de Instalación del pararrayos, las variaciones rápidas de la corriente asociadas a los rayos negativos y las tensiones Inducidas por descargas Indirectas, producen sobretensiones hasta ahora no consideradas y de magnitudes insospechadas en los transformadores de distribución. Como conclusión a este trabajo se plantea un cambio en la filosofía de Instalación de los transformadores de distribución, lo que respaldado por un estudio profundo de los modelos propuestos, puede conducir a una modificación de las normas nacionales de instalación del conjunto transformador-pararrayos, con la consecuente reducción de los costos por quema de los mismos, en cifras anuales que pueden ser del orden de 5 millones de dólares en todo el territorio colombiano.

  20. Miotoxicidade por organofosforados

    Directory of Open Access Journals (Sweden)

    Cavaliere Maria J.

    1996-01-01

    Full Text Available Os organofosforados são um grupo de compostos químicos amplamente utilizados em agropecuária como inseticidas, ocasionando intoxicações acidentais em animais e humanos, e mesmo sendo utilizados em tentativas de suicídio. A toxicidade desses produtos decorre sobretudo de insuficiência cárdio-respiratória por compromentimento do sistema nervoso autônomo. Sabe-se que alguns destes compostos induzem em animais de experimentação e em humanos, uma miopatia caracterizada por degeneração de células musculares, comprometendo sobretudo a musculatura respiratória. Baseado no fato de que este comprometimento contribui para a piora da função respiratória, propõe-se um protocolo de avaliação rotineira de miotoxicidade por compostos organofosforados, através de uma bateria mínima e suficiente de colorações e reações histoquímicas para quantificação da necrose muscular. Utilizaram-se como modelo experimental, grupos de ratos albinos (Wistar intoxicados com o organofosforado paraoxon, com e sem antídotos (atropina ou pralidoxima. Verificou-se nos grupos tratados com paraoxon e paraoxon mais atropina, necrose de fibras musculares no diafragma, que atingia em determinadas áreas até 15% das fibras. No grupo tratado com paraoxon mais pralidoxima, a necrose foi mínima, evidenciando o papel mioprotetor deste último antídoto.

  1. 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.

  2. Coordinated Eph-ephrin signaling guides migration and axon targeting in the avian auditory system

    Directory of Open Access Journals (Sweden)

    Allen-Sharpley Michelle R

    2012-08-01

    Full Text Available Abstract Background In the avian sound localization circuit, nucleus magnocellularis (NM projects bilaterally to nucleus laminaris (NL, with ipsilateral and contralateral NM axon branches directed to dorsal and ventral NL dendrites, respectively. We previously showed that the Eph receptor EphB2 is expressed in NL neuropil and NM axons during development. Here we tested whether EphB2 contributes to NM-NL circuit formation. Results We found that misexpression of EphB2 in embryonic NM precursors significantly increased the number of axon targeting errors from NM to contralateral NL in a cell-autonomous manner when forward signaling was impaired. We also tested the effects of inhibiting forward signaling of different Eph receptor subclasses by injecting soluble unclustered Fc-fusion proteins at stages when NM axons are approaching their NL target. Again we found an increase in axon targeting errors compared to controls when forward signaling was impaired, an effect that was significantly increased when both Eph receptor subclasses were inhibited together. In addition to axon targeting errors, we also observed morphological abnormalities of the auditory nuclei when EphB2 forward signaling was increased by E2 transfection, and when Eph-ephrin forward signaling was inhibited by E6-E8 injection of Eph receptor fusion proteins. Conclusions These data suggest that EphB signaling has distinct functions in axon guidance and morphogenesis. The results provide evidence that multiple Eph receptors work synergistically in the formation of precise auditory circuitry.

  3. 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.

  4. Differential expression of axon-sorting molecules in mouse olfactory sensory neurons.

    Science.gov (United States)

    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. PMID:27207328

  5. The gene ten-1 contributes to axon regeneration accuracy following femtosecond laser axotomy in C. elegans

    Science.gov (United States)

    Stevens, Dylan T.; Mathew, Manoj; Goksör, Mattias; Pilon, Marc

    2012-10-01

    The precise cutting of axons in C. elegans using short laser pulses permits the investigation of parameters that may influence axonal regeneration. This study began by building and optimizing a femtosecond laser axotomy setup that we first used to monitor the effect of cutting axons near or far from the cell body of the PLM mechanosensory neurons in C. elegans. To assess regeneration, we developed a scoring system where the angle between the regenerating trajectory and its direct line to the target is measured; we called this measurement the "angle of regeneration". The results indicate that axons cut near the cell body regenerate better than those cut far from the cell body but nearer their target. The role of teneurins, which are transmembrane proteins with a large extracellular domain that are thought to regulate the remodelling of the extracellular matrix, has not yet been explored as a potential contributor to axon regeneration. We cut PLM axons in wild-type or ten-1 mutant worms, and measured the angle of regeneration 48 hours later, and the frequency of reconnection to the target. Our results show that functional ten-1 contributes to successful axon regeneration.

  6. 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.

  7. EFN-4 functions in LAD-2-mediated axon guidance in Caenorhabditis elegans.

    Science.gov (United States)

    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.

  8. Serial Section Registration of Axonal Confocal Microscopy Datasets for Long-Range Neural Circuit Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    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.

  9. Por mil devaluados pesos

    Directory of Open Access Journals (Sweden)

    Annie Rodríguez Collázos

    2013-03-01

    Full Text Available El estudio de lo popular y lo urbano hasta ahora se ha centrado en el comportamiento y en algunas relaciones de los habitantes con su entorno. “Por mil devaluados pesos. Publicidad popular y urbana”, pretende explorar las formas de publicidad, dispersas en diferentes espacios populares y urbanos en Bogotá, identificando esquemas y formas características de sus propios códigos comunicativos; se centran en un objeto de estudio consistente en las estrategias publicitarias y los códigos comunicativos en los mensajes publicitarios populares en las subculturas de San Victorino, 7 de Agosto y Sanandresito de San José.

  10. gamma-Diketone neuropathy: axon atrophy and the role of cytoskeletal protein adduction.

    Science.gov (United States)

    LoPachin, Richard M; DeCaprio, Anthony P

    2004-08-15

    Multifocal giant neurofilamentous axonal swellings and secondary distal degeneration have been historically considered the hallmark features of gamma-diketone neuropathy. Accordingly, research conducted over the past 25 years has been directed toward discerning mechanisms of axonal swelling. However, this neuropathological convention has been challenged by recent observations that swollen axons were an exclusive product of long-term 2.5-hexanedione (HD) intoxication at lower daily dose-rates (e.g., 175 mg/kg/day); that is, higher HD dose-rates (e.g., 400 mg/kg/day) produced neurological deficits in the absence of axonal swellings. The observation that neurological toxicity can be expressed without axonal swelling suggests that this lesion is not an important pathophysiological event. Instead, several research groups have now shown that axon atrophy is prevalent in nervous tissues of laboratory animals intoxicated over a wide range of HD dose-rates. The well-documented nerve conduction defects associated with axon atrophy, in conjunction with the temporal correspondence between this lesion and the onset of neurological deficits, strongly suggest that atrophy has pathophysiological significance. In this commentary, we present evidence that supports a pathognomonic role for axon atrophy in gamma-diketone neuropathy and suggests that the functional consequences of this lesion mediate the corresponding neurological toxicity. Previous research has demonstrated that HD interacts with proteins via formation of pyrrole adducts. We therefore discuss the possibility that this chemical process is essential to the mechanism of atrophy. Evidence presented in this review suggests that "distal axonopathy" is an inaccurate classification and future nosological schemes should be based on the apparent primacy of axon atrophy. PMID:15289087

  11. 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

  12. 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.

  13. Clinical features and molecular modelling of novel MPZ mutations in demyelinating and axonal neuropathies

    OpenAIRE

    Mandich, Paola; Fossa, Paola; Capponi, Simona; Geroldi, Alessandro; Acquaviva, Massimo; Gulli, Rossella; Ciotti, Paola; MANGANELLI, FIORE; Grandis, Marina; Bellone, Emilia

    2009-01-01

    Mutations in the myelin protein zero (MPZ) gene have been associated with different Charcot–Marie–Tooth disease (CMT) phenotypes, including classical demyelinating CMT1B and the axonal form of the disease (CMT2). The MPZ role in the pathogenesis of both demyelinating and axonal inherited neuropathies was evaluated in the Italian population by screening a cohort of 214 patients with CMT1 or CMT2. A MPZ mutation frequency of 7.9% in demyelinating cases and of 4.8% in axonal cases was observed. ...

  14. Extracellular matrix molecules play diverse roles in the growth and guidance of central nervous system axons

    Directory of Open Access Journals (Sweden)

    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.

  15. [A case of acute motor sensory axonal polyneuropathy after Haemophilus influenzae infection].

    Science.gov (United States)

    Oda, M; Udaka, F; Kubori, T; Oka, N; Kameyama, M

    2000-08-01

    A 47-year-old woman developed consciousness disturbance, and experienced hallucinations while traveling abroad, and then went into critical condition. She was placed in the critical care unit, and had flaccid tetraparesis requiring mechanical ventilation. Haemophilus influenzae was cultured from the sputum. The level of protein of the cerebrospinal fluid was elevated to 114 mg/dl, nerve conduction study showed findings of pure axonal damage, and the sural nerve biopsy revealed severe axonal degeneration. She improved gradually by plasma exchange. The diagnosis of acute motor sensory axonal polyneuropathy (AMSAN) based on autoimmune mechanism was made. We speculate that H. influenzae infection may have elicited AMSAN in this case. PMID:11218707

  16. Axonal recovery after severe traumatic brain injury demonstrated in vivo by 1H MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    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. 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.

  18. Diffuse axonal injury: detection of changes in anisotropy of water diffusion by diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Chan, J.H.M.; Tsui, E.Y.K.; Yuen, M.K. [Department of Diagnostic Radiology, Tuen Mun Hospital, Tsing Chung Koon Road, Tuen Mun, N.T., Hong Kong (China); Peh, W.C.G. [Department of Diagnostic Radiology, Singapore General Hospital (Singapore); Fong, D.; Fok, K.F.; Leung, K.M. [Department of Neurosurgery, Tuen Mun Hospital (Hong Kong); Fung, K.K.L. [Department of Optometry and Radiography, Hong Kong Polytechnic University (China)

    2003-01-01

    Myelinated axons of white matter demonstrate prominent directional differences in water diffusion. We performed diffusion-weighted imaging on ten patients with head injury to explore the feasibility of using water diffusion anisotropy for quantitating diffuse axonal injury. We showed significant decrease in diffusion anisotropy indices in areas with or without signal abnormality on T2 and T2*-weighted images. We conclude that the water diffusion anisotropy index a potentially useful, sensitive and quantitative way of diagnosing and assessing patients with diffuse axonal injury. (orig.)

  19. In vivo axonal transport deficits in a mouse model of fronto-temporal dementia

    Directory of Open Access Journals (Sweden)

    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.

  20. Local protein synthesis in neuronal axons: why and how we study

    OpenAIRE

    Kim, Eunjin; Jung, Hosung

    2015-01-01

    Adaptive brain function and synaptic plasticity rely on dynamic regulation of local proteome. One way for the neuron to introduce new proteins to the axon terminal is to transport those from the cell body, which had long been thought as the only source of axonal proteins. Another way, which is the topic of this review, is synthesizing proteins on site by local mRNA translation. Recent evidence indicates that the axon stores a reservoir of translationally silent mRNAs and regulates their expre...

  1. Axonal localization of neuritin/CPG15 mRNA in neuronal populations through distinct 5' and 3' UTR elements.

    Science.gov (United States)

    Merianda, Tanuja T; Gomes, Cynthia; Yoo, Soonmoon; Vuppalanchi, Deepika; Twiss, Jeffery L

    2013-08-21

    Many neuronal mRNAs are actively transported into distal axons. The 3' untranslated regions (UTRs) of axonal mRNAs often contain cues for their localization. The 3' UTR of neuritin mRNA was shown to be sufficient for localization into axons of hippocampal neurons. Here, we show that neuritin mRNA localizes into axons of rat sensory neurons, but this is predominantly driven by the 5' rather than 3' UTR. Neuritin mRNA shifts from cell body to axon predominantly after nerve crush injury, suggesting that it encodes a growth-associated protein. Consistent with this, overexpression of neuritin increases axon growth but only when its mRNA localizes into the axons. PMID:23966695

  2. Efecto hipotensor del extracto de ajo (Allium sativum macerado por 18 semanas en un modelo experimental in vivo

    Directory of Open Access Journals (Sweden)

    David Chaupis-Meza

    2014-09-01

    Full Text Available Objetivos. Determinar si el extracto de ajo (Allium sativum macerado por 18 semanas tiene igual o mejor efecto hipotensor que el captopril en ratas. Materiales y métodos. Se realizó un estudio experimental in vivo con ratas machos Holtzman, clasificados en cinco grupos: 100, 500 y 1000 mg/kg de extracto de ajo, Captopril de 100 mg/kg y un grupo vehículo. El L-NAME (N- -nitro L-arginina-metil-éster administrado vía intraperitoneal 50 mg/kg desde el inicio del experimento, elevó la presión arterial desde el tercer día. El análisis estadístico consistió en las pruebas T de Student para medias pareadas, ANOVA y comparación múltiple de Scheffe. Resultados. El ajo macerado extraído por un proceso hidroalcohólico durante 18 semanas provocó una disminución de la presión arterial en animales de experimentación. El análisis de los tratamientos sobre la presión arterial media (PAM, obtuvieron diferencias significativas desde el tercer día. La comparación sobre la PAM final versus PAM basal (medias no diferentes y el efecto hipotensor (% fueron: ajo-100 (p=0,008, 59,8%; ajo-500 (p=0,021, 80,6%; ajo-1000 (p=0,034, 88,5%, Captopril (p=0,437, 99,9% y vehículo (p=0,001, 0%. Conclusiones. El ajo macerado a un periodo de 18 semanas resultó eficaz para producir un efecto hipotensor en ratas, inducidas a hipertensión arterial por L-NAME

  3. Efecto hipotensor del extracto de ajo (Allium sativum macerado por 18 semanas en un modelo experimental in vivo

    Directory of Open Access Journals (Sweden)

    David Chaupis-Meza

    2014-07-01

    Full Text Available Objetivos. Determinar si el extracto de ajo (Allium sativum macerado por 18 semanas tiene igual o mejor efecto hipotensor que el captopril en ratas. Materiales y métodos. Se realizó un estudio experimental in vivo con ratas machos Holtzman, clasificados en cinco grupos: 100, 500 y 1000 mg/kg de extracto de ajo, Captopril de 100 mg/kg y un grupo vehículo. El L-NAME (N- -nitro L-arginina-metil-éster administrado vía intraperitoneal 50 mg/kg desde el inicio del experimento, elevó la presión arterial desde el tercer día. El análisis estadístico consistió en las pruebas T de Student para medias pareadas, ANOVA y comparación múltiple de Scheffe. Resultados. El ajo macerado extraído por un proceso hidroalcohólico durante 18 semanas provocó una disminución de la presión arterial en animales de experimentación. El análisis de los tratamientos sobre la presión arterial media (PAM, obtuvieron diferencias significativas desde el tercer día. La comparación sobre la PAM final versus PAM basal (medias no diferentes y el efecto hipotensor (% fueron: ajo-100 (p=0,008, 59,8%; ajo-500 (p=0,021, 80,6%; ajo-1000 (p=0,034, 88,5%, Captopril (p=0,437, 99,9% y vehículo (p=0,001, 0%. Conclusiones. El ajo macerado a un periodo de 18 semanas resultó eficaz para producir un efecto hipotensor en ratas, inducidas a hipertensión arterial por L-NAME

  4. Ojo por ojo

    OpenAIRE

    Ramón del Llano Ibáñez

    2011-01-01

    Nuestro pan y café de la mañana se acompaña de noticias alrededor de ejecuciones, de fosas clandestinas, de batallas del ejército, de balaceras en las calles y civiles caídos por balas perdidas : la muerte acompaña nuestro desayuno. Las calaveras de azúcar del día de muertos hoy son calaveras reales y amargas : 40 000 muertos en cuatro años después que el Presidente Calderón declaró la guerra a los narcotraficantes. Se han apresado a varios e importantes miembros de los cárteles : pero han si...

  5. Sepsis por shigella flexneri

    Directory of Open Access Journals (Sweden)

    César Cabrera C

    2005-04-01

    Full Text Available Se presenta un caso raro de sepsis por Shigella flexneri en una paciente de 45 años de edad quien estando hospitalizada para el estudio de un tumor cerebral, requirió el uso de manitol y dosis altas de corticoides; luego de ello presenta deposiciones líquidas con moco y sangre, desarrolla síndrome de respuesta inflamatoria sistémica, luego se aísla Shigella flexneri en el hemocultivo; recibió tratamiento antibiótico con ciprofloxacina. Se describen las características del caso y se comenta de acuerdo con la revisión de literatura.

  6. Onicomicosis por hongos fuliginosos

    Directory of Open Access Journals (Sweden)

    Ingrid Salas-Campos

    2009-12-01

    Full Text Available Justificación y objetivo: Las infecciones de las uñas producidas por hongos son un problema de frecuente consulta dermatológica. Los dermatofitos son la mayor causa de estas infecciones, siendo Trichophyton rubrum el agente etiológico más importante. Sin embargo, los hongos no dermatofitos, tanto hialinos como fuliginosos, pueden ser también responsables de estos cuadros clínicos. Debido a que estos hongos tienden a ser resistentes a los antimicóticos comúnmente usados para tratar las onicomicosis, es que se hace indispensable que el clínico se asegure por medio de un examen de laboratorio de la etiología de la infección. Métodos: Se estudiaron tres casos de pacientes con lesiones en uñas, que acudieron al laboratorio de Micología Médica, Facultad de Microbiología, Universidad de Costa Rica. Se realizaron los análisis de rutina para aislamiento e identificación de hongos patógenos. Resultados: En los tres casos estudiados se observó al examen directo micelio fuliginoso. En uno de los casos se aisló e identificó Scytalidium dimidiatum, hongo que presenta resistencia a los antifúngicos utilizados para tratar onicomicosis. Conclusión. El reporte de hongos diferentes a los dermatofitos como agentes etiológicos de onicomicosis es importante para que el médico pueda elegir el tratamiento más recomendado para este tipo de infección.

  7. Motivado por cirujanos

    Directory of Open Access Journals (Sweden)

    Carlos Salazar-Vargas

    2010-12-01

    Full Text Available Comenzaba la década de los 60 y nuestro grupo nerviosamente iniciaba lecciones en los hospitales de San José. En aquellos años, el estudiante de medicina empezaba su contacto con pacientes, por lo menos 1 ó 2 años después de iniciada la carrera. El estudio del ser humano normal que ya habíamos concluido, continuaba con el del enfermo, y más adelante aprenderíamos el tratamiento. La enfermedad descrita en el libro, de pronto se convertía en un enfermo, y es a este quien hoy veíamos, cohibido pero inquisidor, en la cama de un hospital. Los profesores nos enseñaban a interrogar y a examinar a los pacientes, y cada gesto suyo, cada pregunta, cada maniobra, eran celosamente guardados en la memoria de los educandos. Con claridad percibíamos, aun a temprana edad, las diferencias entre los especialistas, y casi de manera involuntaria, cada quien iba tomando partido y escogía su futuro camino. Fue durante esos tempranos años, cuando mi vida se cruzó con la de 7 maravillosas personas y excelentes cirujanos, que marcaron para siempre mi destino y, sin quererlo ellos, me hicieron inclinarme por la cirugía. Dos eran serios y profundamente académicos: el Dr. Manuel Aguilar Bonilla y el Dr. Vesalio Guzmán Calleja; 3, decididos, incansables y muy hábiles: el Dr. Longino Soto Pacheco, el Dr. Claudio Orlich Carranza y el Dr. Carlos Prada Díaz, y 2, abordables, prácticos, joviales y amistosos: el Dr. Fernando Valverde Soley y el Dr. Randall Ferris Iglesias….

  8. Evaluation of the recombination in somatic cells induced by radiation in different stages of Drosophila larval development; Evaluacion de la recombinacion en celulas somaticas inducida por radiacion en diferentes etapas del desarrollo larvario de Drosophila

    Energy Technology Data Exchange (ETDEWEB)

    Cruces, M.P.; Morales R, P. [Instituto nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The mitotic recombination can happen spontaneously and its frequency is very low, however the recombination rate of a cell can be increased by the exposure to agents which cause damage to DNA. This type of agents are knew commonly as recombinogens. The ionizing radiation and a numerous chemical agents can be mentioned (Vogel, 1992). The objective of this work is to determine if the mutation/recombination rate induced by gamma rays varies with the development stage. In order to realize this investigation it was used the mutation and somatic recombination test of Drosophila wing (Graf and col. 1984). The mwh/ mwh and flr{sup 3}/TM3, Ser stocks were used. (Author)

  9. Microstructural characteristics of the hydroxyapatite and its influence in the Tl signal induced by gamma radiation; Caracteristicas microestructurales de la hidroxiapatita y su influencia en la senal Tl inducida por la radiacion gamma

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza A, D.; Gonzalez M, P.R.; Hernandez A, M. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Estrada G, R. [Depto. de Fisica y Matematicas, Universidad Iberoamericana, Santa Fe, 01000 Mexico D.F. (Mexico); Rodriguez L, V. [Centro Universitario de Vinculacion, BUAP, Puebla (Mexico)

    2003-07-01

    The analysis carried out on different materials has shown that the quantity and type of dopants play an important role in the behaviour thermoluminescent signal induced by the ionizing radiation. More recent studies have also shown that the grain size influences strongly in the thermoluminescent signal. Plus still, the crystal growth habit and the crystalline degree have an important effect in the type and intensity thermoluminescent signal. In this sense, we present this work on the analysis of the thermoluminescent signal induced by the gamma radiation in the hydroxyapatite ceramic. Depending the growth habit, a variation of the peak temperature location, signal intensity and linearity range was observed; in particular cases a lineal relationship between glow curve and radiation dose was in the range from 2 to 1000 Gray. These results are complemented with a microstructural and crystalline degree analysis through scanning electron microscopy and X-ray Diffraction. The dose-response over the whole irradiation range opening up the possibility of employing this bio material as a dosimeter. (Author)

  10. Influence of temperature in TL signal induced by gamma radiation in zircon prepared by sol gel via; Influencia de la temperatura en la senal TL inducida por la radiacion gamma en zirconia preparada via solgel

    Energy Technology Data Exchange (ETDEWEB)

    Salas, P.; Castano, V.M. [Instituto de Fisica, UNAM, Laboratorio Juriquilla, A.P. 1-1010, 76001 Queretaro (Mexico); Mendoza A, D.; Gonzalez M, P.R. [ININ, Mexico, D.F. (Mexico); Rosa C, E. de la [Centro de Investigaciones en Optical, Leon, Gto. (Mexico)

    2000-07-01

    In this work, it was realized a study of the temperature effects in thermoluminescent signal (Tl) induced by gamma radiation in zircon, which was prepared by the sol gel method. According to the obtained results, the zircon thermically treated at 500 C or over is sensitive to radiation. This sensitivity is increased when the temperature in study is augmented, moreover, the Tl spectra form also is modified with the temperature increment. The samples thermically treated at 750 C or over present a linear response in the dose interval 27 to 165 Gy; therefore, such materials result promissories for dosimetric purposes. (Author)

  11. Variations in pH caused by porous ceramic capsules in water sampling in non-saturated areas; Variaciones del pH inducidas por las capsulas de ceramica porosa en el muestreo de agua en la zona no saturada

    Energy Technology Data Exchange (ETDEWEB)

    Torre de la Sanchez, M. L.; Grande Gil, J. A.; Garrido Morillo, R. [Escuela Politecnica Superior La Rabida. Palos de La Frontera. Huelva (Spain)

    1999-05-01

    Porous ceramic capsules are a very useful tool for water sampling in non-saturated areas. However, several authors have found variations in pH in the water collected by such capsules. This paper compares the variation in pH distilled water and in different concentrations of saline solution. A large increase in pH was found due to the release process and subsequent precipitation of calcium ions from the ceramic. (Author) 5 refs.

  12. Las alteraciones inducidas por el laboreo agrícola: la influencia del movimiento vertical en los yacimientos paleolíticos de los páramos de Montemayor-Corcos (Valladolid y Burgos

    Directory of Open Access Journals (Sweden)

    Fernando DÍEZ MARTÍN

    2009-12-01

    Full Text Available RESUMEN: Las altetaciones postdeposicionales de catáctet cultutal han sido los fenómenos de cambio más destacados en los asentamientos paleolíticos situados en los pátamos de Montemayor-Corcos. Este trabajo profundiza en una de las implicaciones fundamentales de las fuerzas del laboreo agrícola sobre estos conjuntos líticos: el movimiento vertical y su relación con la representatividad de las muestras prospectadas y analizadas en superficie.ABSTRACT: Cultural post-depositional disturbances have been the most important change phenomena in the Palaeolithic settlements located on the Montemayor-Corcos moors. This paper focuses on one of the main implications of tillage forces in lithic scatters: vertical displacement and its bearing on the representativeness of surveyed and analysed surface samples.

  13. Validation of the technique of kinetic fosforimetria induced by laser for the determination of the concentration of uranium in urine; Validacion de la tecnica de fosforimetria cinetica inducida por laser para la determinacion de la concentracion de uranio en orina

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.; Sierra, I.; Benito, P.; Lopez, C.

    2013-07-01

    This paper describes the methodology used to conduct the validation of the method of determination of uranium using the technique of Kinetic Phosphorescence Analyser (KPA) The technical requirements of the standard 17025 stresses the need for validation samples KPA urine of workers exposed to risk of internal contamination. (Author)

  14. Interval for the expression of the adaptive response induced by gamma radiation in leucocytes of mouse In vivo; Intervalo para la expresion de la respuesta adaptativa inducida por radiacion gamma en leucocitos de raton In vivo

    Energy Technology Data Exchange (ETDEWEB)

    Mendiola C, M.T.; Morales R, P. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The interval between the adaptive gamma radiation dose (0.01 Gy) and challenge (1.0 Gy) capable to induce the maximum expression of the adaptive response in lymphocytes of mouse In vivo. The animals were exposed to the mentioned doses with different intervals among both (1, 1.5, 5 or 18 hr). By means of the unicellular electrophoresis in gel technique, four damage parameters were analysed. The results showed that from the 1 hr interval an adaptive response was produced since in the pretreated organisms with 0.01 Gy the cells present lesser damage than in those not adapted. The maximum response was induced with the intervals between 2.5 and 5 hr and even though it persisted until 18 hr, the effect was reducing. (Author)

  15. Reprogramación del polen a embriogénesis inducida por estrés: identidad celular, muerte celular programada y papel de la metilación de DNA

    OpenAIRE

    Solís González, María Teresa

    2012-01-01

    El desarrollo del grano de polen es un proceso estrictamente regulado a nivel génico que conduce a la formación de un organismo haploide, el gametofito masculino o grano de polen, cuyas células poseen una alta especialización, necesaria para su importante función en la germinación del tubo polínico y doble fecundación de las plantas con flores. Mediante la aplicación de un tratamiento de estrés in vitro en la etapa adecuada del desarrollo, concretamente en la fase de microspora...

  16. Setting-up of the Laser Induced Fluorescence diagnostic. Measurements of Cr density in a neon glow discharge; Puesta a punto del diagnstico de fluorescencia inducida por laser. Medidas de densidad de Cr en Glow discharg de Neon

    Energy Technology Data Exchange (ETDEWEB)

    Tafalla, D.; Cal, E. de la; Tabares, F. L.

    1994-07-01

    A plasma diagnostic based on the Laser Induced Fluorescence (LIF) technique has been set up in the Fusion Division at the CIEMAT. In a preliminary experiment, the density of sputtered chromium atoms produced in a neon glow discharge was measured. Firstly, the laser beam was characterized by calibration of its wavelength, bandwidth and energy profile and Rayleigh scattering in N2 was used for the optical system calibration. An absolute density of Cr atoms of n {approx} 5x10 cm was obtained in discharges at 100 mA and pressure of 15 mTorr and a linear dependence of the LIF signal us. current was found. These values are in agreement with those expected from the tabulated sputtering yields and the thermalization and diffusion of the sputtered atoms into the Ne plasma. (Author) 19 refs.

  17. Utilización de modelos de simulación para estimar el riesgo de epidemias inducidas por la presencia europea durante el contacto indirecto en Tierra del Fuego

    OpenAIRE

    Fugassa, Martín H.

    2003-01-01

    El Contacto Indirecto en el archipiélago de Tierra del Fuego fue un proceso extenso iniciado probablemente con el viaje de Magallanes en 1520 y que acaba en forma difusa hacia principios del siglo XIX, con los primeros establecimientos y actividad económica permanente. Mediante un trabajo anterior, Fugassa y Guichón establecen un listado de posibles enfermedades infecciosas que habrían actuado durante este período. En el presente trabajo analizamos aquellas enfermedades infecciosas de dispers...

  18. First Patagonian Course on 'Diagnosis and Therapy of Injuries Induced by Ionizing Radiation'; Primer curso patagonico 'Diagnostico y Tratamiento de Lesiones Inducidas por Radiaciones Ionizantes'

    Energy Technology Data Exchange (ETDEWEB)

    Bellotti, Mariela I., E-mail: bellotti@cab.cnea.gov.ar [Comision Nacional de Energia Atomica (CAB/CNEA), San Carlos de Bariloche (Argentina). Centro Atomico Bariloche. Lab. de Cavitacion y Biotecnologia; Andres, Pablo A., E-mail: andresp@cab.cnea.gov.ar [Comision Nacional de Energia Atomica (CAB/CNEA), San Carlos de Bariloche (Argentina). Centro Atomico Bariloche. Division Proteccion Radiologica; Cascón, Adriana S., E-mail: adrianacascon@yahoo.com [Instituto de Medicina, Radiomedicina y Seguridad (IMERASE SA), Buenos Aires, (Argentina)

    2013-07-01

    In Patagonia there are academic centers, health and industrial facilities that use ionizing radiations in its usual practices. However, they do not have protocols that respond to local needs. For this reason was held from October 5 to November 10, 2012 in Bariloche Atomic Center, a training course for health personnel. The range of topics covered ranged from the definition of dosimetry quantities, types of radiation and biological dosimetry, biological effects, radiation acute syndrome, radiation-induced cutaneous syndrome, internal contamination, screening in radiological emergencies, etc.The course provided a theoretical and practical guide about how to recognize and treat people exposed to radiations, guidelines for acting in radiological emergencies and a perception of the psychosocial impact of the radiation accidents.The result was a pocket book for health personnel that will be used in case of having a patient with radiation induced injury.

  19. Heterómeros de receptores de dopamina como dianas terapéuticas en la enfermedad de Parkinson y en discinesias inducidas por el tratamiento con L-DOPA

    OpenAIRE

    Farré Pérez, Daniel

    2014-01-01

    La desregulación de la transmisión dopaminérgica da lugar a la enfermedad de Parkinson. Los receptores de dopamina interaccionan con receptores tanto de la misma familia como con otros tipos de receptores, para formar complejos heteroméricos organizados. Fruto de nuestro trabajo, hemos descubierto que los receptores de adenosina A2A, de cannabinoides CB1 y de dopamina D2 forman heterómeros en el núcleo caudado de Macaca fascicularis no lesionados o lesionados con MPTP pero no en el putamen. H...

  20. Resistencia a la insulina inducida por acidos grasos en células de músculo esquelético L6E9: papel de la carnitina palmitoiltransferasa I (CPT-I)

    OpenAIRE

    Sebastián Muñoz, David

    2006-01-01

    La resistencia a la insulina es un estado patológico que se define como la incapacidad del organismo de responder normalmente a las acciones de la insulina. Este estado está ligado a la obesidad, al estilo sedentario de vida y es responsable en gran medida de la aparición de la diabetes de tipo 2. Aunque tradicionalmente el estudio de esta patología se había centrado en el metabolismo de carbohidratos, en las últimas décadas se ha producido un cambio hacia el estudio del metabolismo de ácidos...

  1. 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...

  2. 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.

  3. Mechanisms of sodium channel clustering and its influence on axonal impulse conduction.

    Science.gov (United States)

    Freeman, Sean A; Desmazières, Anne; Fricker, Desdemona; Lubetzki, Catherine; Sol-Foulon, Nathalie

    2016-02-01

    The efficient propagation of action potentials along nervous fibers is necessary for animals to interact with the environment with timeliness and precision. Myelination of axons is an essential step to ensure fast action potential propagation by saltatory conduction, a process that requires highly concentrated voltage-gated sodium channels at the nodes of Ranvier. Recent studies suggest that the clustering of sodium channels can influence axonal impulse conduction in both myelinated and unmyelinated fibers, which could have major implications in disease, particularly demyelinating pathology. This comprehensive review summarizes the mechanisms governing the clustering of sodium channels at the peripheral and central nervous system nodes and the specific roles of their clustering in influencing action potential conduction. We further highlight the classical biophysical parameters implicated in conduction timing, followed by a detailed discussion on how sodium channel clustering along unmyelinated axons can impact axonal impulse conduction in both physiological and pathological contexts. PMID:26514731

  4. 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

  5. Calcium-Activated Potassium Channels at Nodes of Ranvier Secure Axonal Spike Propagation

    Directory of Open Access Journals (Sweden)

    Jan Gründemann

    2015-09-01

    Full Text Available Functional connectivity between brain regions relies on long-range signaling by myelinated axons. This is secured by saltatory action potential propagation that depends fundamentally on sodium channel availability at nodes of Ranvier. Although various potassium channel types have been anatomically localized to myelinated axons in the brain, direct evidence for their functional recruitment in maintaining node excitability is scarce. Cerebellar Purkinje cells provide continuous input to their targets in the cerebellar nuclei, reliably transmitting axonal spikes over a wide range of rates, requiring a constantly available pool of nodal sodium channels. We show that the recruitment of calcium-activated potassium channels (IK, KCa3.1 by local, activity-dependent calcium (Ca2+ influx at nodes of Ranvier via a T-type voltage-gated Ca2+ current provides a powerful mechanism that likely opposes depolarizing block at the nodes and is thus pivotal to securing continuous axonal spike propagation in spontaneously firing Purkinje cells.

  6. Contrast and stability of the axon diameter index from microstructure imaging with diffusion MRI

    DEFF Research Database (Denmark)

    Dyrby, Tim B; Søgaard, Lise V; Hall, Matt G;

    2013-01-01

    (max) ) on a scanner influence the sensitivity to a range of axon diameters. Multishell high-angular-diffusion-imaging (HARDI) protocols for G(max) of 60, 140, 200, and 300 mT/m were optimized for the pulsed-gradient-spin-echo (PGSE) sequence. Data were acquired on a fixed monkey brain and Monte-Carlo simulations...... supported the results. Increasing G(max) reduces within-voxel variation of the axon diameter index and improves contrast beyond what is achievable with higher signal-to-noise ratio. Simulations reveal an upper bound on the axon diameter (∼10 μm) that pulsed-gradient-spin-echo measurements are sensitive to......(max) for enhancing contrast between axon diameter distributions and are, therefore, relevant in general for microstructure imaging methods and highlight the need for increased G(max) on future commercial systems. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc....

  7. 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...

  8. Calcium-dependent proteasome activation is required for axonal neurofilament degradation.

    Science.gov (United States)

    Park, Joo Youn; Jang, So Young; Shin, Yoon Kyung; Suh, Duk Joon; Park, Hwan Tae

    2013-12-25

    Even though many studies have identified roles of proteasomes in axonal degeneration, the molecular mechanisms by which axonal injury regulates proteasome activity are still unclear. In the present study, we found evidence indicating that extracellular calcium influx is an upstream regulator of proteasome activity during axonal degeneration in injured peripheral nerves. In degenerating axons, the increase in proteasome activity and the degradation of ubiquitinated proteins were significantly suppressed by extracellular calcium chelation. In addition, electron microscopic findings revealed selective inhibition of neurofilament degradation, but not microtubule depolymerization or mitochondrial swelling, by the inhibition of calpain and proteasomes. Taken together, our findings suggest that calcium increase and subsequent proteasome activation are an essential initiator of neurofilament degradation in Wallerian degeneration. PMID:25206662

  9. Calcium-dependent proteasome activation is required for axonal neurofilament degradation

    Institute of Scientific and Technical Information of China (English)

    Joo Youn Park; So Young Jang; Yoon Kyung Shin; Duk Joon Suh; Hwan Tae Park

    2013-01-01

    Even though many studies have identified roles of proteasomes in axonal degeneration, the mo-lecular mechanisms by which axonal injury regulates proteasome activity are stil unclear. In the present study, we found evidence indicating that extracellular calcium influx is an upstream regula-tor of proteasome activity during axonal degeneration in injured peripheral nerves. In degenerating axons, the increase in proteasome activity and the degradation of ubiquitinated proteins were sig-nificantly suppressed by extracellular calcium chelation. In addition, electron microscopic findings revealed selective inhibition of neurofilament degradation, but not microtubule depolymerization or mitochondrial swel ing, by the inhibition of calpain and proteasomes. Taken together, our findings suggest that calcium increase and subsequent proteasome activation are an essential initiator of neurofilament degradation in Wal erian degeneration.

  10. 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.

  11. SNTF immunostaining reveals previously undetected axonal pathology in traumatic brain injury.

    Science.gov (United States)

    Johnson, Victoria E; Stewart, William; Weber, Maura T; Cullen, D Kacy; Siman, Robert; Smith, Douglas H

    2016-01-01

    Diffuse axonal injury (DAI) is a common feature of severe traumatic brain injury (TBI) and may also be a predominant pathology in mild TBI or "concussion". The rapid deformation of white matter at the instant of trauma can lead to mechanical failure and calcium-dependent proteolysis of the axonal cytoskeleton in association with axonal transport interruption. Recently, a proteolytic fragment of alpha-II spectrin, "SNTF", was detected in serum acutely following mild TBI in patients and was prognostic for poor clinical outcome. However, direct evidence that this fragment is a marker of DAI has yet to be demonstrated in either humans following TBI or in models of mild TBI. Here, we used immunohistochemistry (IHC) to examine for SNTF in brain tissue following both severe and mild TBI. Human severe TBI cases (survival <7d; n = 18) were compared to age-matched controls (n = 16) from the Glasgow TBI archive. We also examined brains from an established model of mild TBI at 6, 48 and 72 h post-injury versus shams. IHC specific for SNTF was compared to that of amyloid precursor protein (APP), the current standard for DAI diagnosis, and other known markers of axonal pathology including non-phosphorylated neurofilament-H (SMI-32), neurofilament-68 (NF-68) and compacted neurofilament-medium (RMO-14) using double and triple immunofluorescent labeling. Supporting its use as a biomarker of DAI, SNTF immunoreactive axons were observed at all time points following both human severe TBI and in the model of mild TBI. Interestingly, SNTF revealed a subpopulation of degenerating axons, undetected by the gold-standard marker of transport interruption, APP. While there was greater axonal co-localization between SNTF and APP after severe TBI in humans, a subset of SNTF positive axons displayed no APP accumulation. Notably, some co-localization was observed between SNTF and the less abundant neurofilament subtype markers. Other SNTF positive axons, however, did not co-localize with any

  12. Fisiopatología del síndrome de Guillain Barré axonal Physiopathology of axonal acute Guillain Barré syndrome

    OpenAIRE

    Juan Guillermo Montoya Ch.; Diana P. Martínez T.; Jaime Carrizosa Moog; Beatriz Aguirre L.

    2002-01-01

    Se describe la fisiopatología del síndrome de Guillain Barré axonal. Se consideran especialmente cinco aspectos: 1) Agentes etiológicos, específicamente el Campylobacter jejuni. 2) Susceptibilidad genética humana. 3) Mimetismo molecular entre lipopolisacáridos y lipoproteínas. 4) Mecanismo de acción de los anticuerpos antigangliósidos y 5) Hallazgos patológicos. The physiopathology of axonal acute Guillain Barré syndrome is described. Five aspects are considered, namely: 1) Etiologic agents e...

  13. Hydrogels as scaffolds and delivery systems to enhance axonal regeneration after injuries

    Directory of Open Access Journals (Sweden)

    Oscar A. Carballo-Molina

    2015-02-01

    Full Text Available Damage caused to neural tissue by disease or injury frequently produces a discontinuity in the nervous system. Such damage generates diverse alterations that are commonly permanent, due to the limited regeneration capacity of the adult nervous system, particularly the Central Nervous System (CNS. The cellular reaction to noxious stimulus leads to several events such as the formation of glial and fibrous scars, which inhibit axonal regeneration in both the CNS and the Peripheral Nervous System (PNS. Although in the PNS there is some degree of nerve regeneration, it is common that the growing axons reinnervate incorrect areas, causing mismatches. Providing a permissive substrate for axonal regeneration in combination with delivery systems for the release of molecules, which enhances axonal growth, could increase regeneration and the recovery of functions in the CNS or the PNS. Currently, there are no effective vehicles to supply growth factors or cells to the damaged/diseased nervous system. Hydrogels are polymers that are biodegradable, biocompatible and have the capacity to deliver a large range of molecules in situ. The inclusion of cultured neural cells into hydrogels forming three-dimensional structures allows the formation of synapses and neuronal survival. There is also evidence showing that hydrogels constitute an amenable substrate for axonal growth of endogenous or grafted cells, overcoming the presence of axonal regeneration inhibitory molecules, in both the central and peripheral nervous systems. Recent experiments suggest that hydrogels can carry and deliver several proteins relevant for improving neuronal survival and axonal growth. Although the use of hydrogels is appealing, its effectiveness is still a matter of discussion, and more results are needed to achieve consistent recovery using different parameters. This review also discusses areas of opportunity where hydrogels can be applied, in order to promote axonal regeneration of

  14. Skin incision induces expression of axonal regeneration-related genes in adult rat spinal sensory neurons

    OpenAIRE

    Hill, Caitlin E.; Harrison, Benjamin J; Rau, Kris K.; Hougland, M. Tyler; Bunge, Mary Bartlett; Lorne M. Mendell; Petruska, Jeffrey C.

    2010-01-01

    Skin incision and nerve injury both induce painful conditions. Incisional and post-surgical pain is believed to arise primarily from inflammation of tissue and the subsequent sensitization of peripheral and central neurons. The role of axonal regeneration-related processes in development of pain has only been considered when there has been injury to the peripheral nerve itself, even though tissue damage likely induces injury of resident axons. We sought to determine if skin incision would aff...

  15. Microtubules Have Opposite Orientation in Axons and Dendrites of Drosophila Neurons

    OpenAIRE

    Stone, Michelle C.; Roegiers, Fabrice; Rolls, Melissa M

    2008-01-01

    In vertebrate neurons, axons have a uniform arrangement of microtubules with plus ends distal to the cell body (plus-end-out), and dendrites have equal numbers of plus- and minus-end-out microtubules. To determine whether microtubule orientation is a conserved feature of axons and dendrites, we analyzed microtubule orientation in invertebrate neurons. Using microtubule plus end dynamics, we mapped microtubule orientation in Drosophila sensory neurons, interneurons, and motor neurons. As expec...

  16. Sustained axon-glial signaling induces Schwann cell hyperproliferation, Remak bundle myelination, and tumorigenesis

    OpenAIRE

    Gómez-Sánchez, José A.; López de Armentia, Mikel; Luján, Rafael; Kessaris, Nicoletta; Richardson, William D.; Cabedo, Hugo

    2009-01-01

    Type III neuregulins exposed on axon surfaces control myelination of the peripheral nervous system. It has been shown, for example, that threshold levels of type IIIβ1a neuregulin dictate not only the myelination fate of axons but also myelin thickness. Here we show that another neuregulin isoform, type III-β3, plays a distinct role in myelination. Neuronal overexpression of this isoform in mice stimulates Schwann cell proliferation and dramatically enlarges peripheral nerves and ganglia -whi...

  17. Axon-Schwann cell interactions during peripheral nerve regeneration in zebrafish larvae

    OpenAIRE

    Ceci, Maria Laura; Mardones-Krsulovic, Camila; SÁNCHEZ, MARIO; Valdivia, Leonardo E.; Allende, Miguel L

    2014-01-01

    Background Peripheral nerve injuries can severely affect the way that animals perceive signals from the surrounding environment. While damage to peripheral axons generally has a better outcome than injuries to central nervous system axons, it is currently unknown how neurons re-establish their target innervations to recover function after injury, and how accessory cells contribute to this task. Here we use a simple technique to create reproducible and localized injury in the posterior lateral...

  18. Purkinje cell axonal anatomy: quantifying morphometric changes in essential tremor versus control brains

    OpenAIRE

    Babij, Rachel; Lee, Michelle; Cortés, Etty; Vonsattel, Jean-Paul G.; Faust, Phyllis L.; Louis, Elan D.

    2013-01-01

    Growing clinical, neuro-imaging and post-mortem data have implicated the cerebellum as playing an important role in the pathogenesis of essential tremor. Aside from a modest reduction of Purkinje cells in some post-mortem studies, Purkinje cell axonal swellings (torpedoes) are present to a greater degree in essential tremor cases than controls. Yet a detailed study of more subtle morphometric changes in the Purkinje cell axonal compartment has not been undertaken. We performed a detailed morp...

  19. Wnt Signalling Promotes Actin Dynamics during Axon Remodelling through the Actin-Binding Protein Eps8.

    Directory of Open Access Journals (Sweden)

    Eleanna Stamatakou

    Full Text Available Upon arrival at their synaptic targets, axons slow down their growth and extensively remodel before the assembly of presynaptic boutons. Wnt proteins are target-derived secreted factors that promote axonal remodelling and synaptic assembly. In the developing spinal cord, Wnts secreted by motor neurons promote axonal remodelling of NT-3 responsive dorsal root ganglia neurons. Axon remodelling induced by Wnts is characterised by growth cone pausing and enlargement, processes that depend on the re-organisation of microtubules. However, the contribution of the actin cytoskeleton has remained unexplored. Here, we demonstrate that Wnt3a regulates the actin cytoskeleton by rapidly inducing F-actin accumulation in growth cones from rodent DRG neurons through the scaffold protein Dishevelled-1 (Dvl1 and the serine-threonine kinase Gsk3β. Importantly, these changes in actin cytoskeleton occurs before enlargement of the growth cones is evident. Time-lapse imaging shows that Wnt3a increases lamellar protrusion and filopodia velocity. In addition, pharmacological inhibition of actin assembly demonstrates that Wnt3a increases actin dynamics. Through a yeast-two hybrid screen, we identified the actin-binding protein Eps8 as a direct interactor of Dvl1, a scaffold protein crucial for the Wnt signalling pathway. Gain of function of Eps8 mimics Wnt-mediated axon remodelling, whereas Eps8 silencing blocks the axon remodelling activity of Wnt3a. Importantly, blockade of the Dvl1-Eps8 interaction completely abolishes Wnt3a-mediated axonal remodelling. These findings demonstrate a novel role for Wnt-Dvl1 signalling through Eps8 in the regulation of axonal remodeling.

  20. Negative regulation of glial engulfment activity by Draper terminates glial responses to axon injury

    OpenAIRE

    Logan, Mary A.; Hackett, Rachel; Doherty, Johnna; Sheehan, Amy; Speese, Sean D.; Freeman, Marc R

    2012-01-01

    Neuronal injury elicits potent cellular responses from glia, but molecular pathways modulating glial activation, phagocytic function, and termination of reactive responses remain poorly defined. Here we show that positive or negative regulation of glial reponses to axon injury are molecularly encoded by unique isoforms of the Drosophila engulfment receptor Draper. Draper-I promotes engulfment of axonal debris through an immunoreceptor tyrosine-based activation motif (ITAM). In contrast, Drape...

  1. Axonal neuregulin 1 is a rate limiting but not essential factor for nerve remyelination

    OpenAIRE

    Fricker, Florence R.; Antunes-Martins, Ana; Galino, Jorge; Paramsothy, Remi; La Russa, Federica; Perkins, James; Goldberg, Rebecca; Brelstaff, Jack; Zhu, Ning; McMahon, Stephen B; Orengo, Christine; Garratt, Alistair N.; Birchmeier, Carmen; David L H Bennett

    2013-01-01

    Neuregulin 1 acts as an axonal signal that regulates multiple aspects of Schwann cell development including the survival and migration of Schwann cell precursors, the ensheathment of axons and subsequent elaboration of the myelin sheath. To examine the role of this factor in remyelination and repair following nerve injury, we ablated neuregulin 1 in the adult nervous system using a tamoxifen inducible Cre recombinase transgenic mouse system. The loss of neuregulin 1 impaired remyelination aft...

  2. Mild hypothermia for treatment of diffuse axonal injury: a quantitative analysis of diffusion tensor imaging

    OpenAIRE

    Jing, Guojie; Yao, Xiaoteng; Li, Yiyi; Xie, Yituan; Li, Wang#x2019;an; LIU, Kejun; Jing, Yingchao; Li, Baisheng; Lv, Yifan; Ma, Baoxin

    2014-01-01

    Fractional anisotropy values in diffusion tensor imaging can quantitatively reflect the consistency of nerve fibers after brain damage, where higher values generally indicate less damage to nerve fibers. Therefore, we hypothesized that diffusion tensor imaging could be used to evaluate the effect of mild hypothermia on diffuse axonal injury. A total of 102 patients with diffuse axonal injury were randomly divided into two groups: normothermic and mild hypothermic treatment groups. Patient's m...

  3. Topographic mapping of the axons of the femoral chordotonal organ neurons in the cricket Gryllus bimaculatus.

    Science.gov (United States)

    Nishino, H

    2000-01-01

    Central projections of the femoral chordotonal organ (FCO) neurons in the cricket Gryllus bimaculatus were investigated by selectively staining small numbers of axons. The FCOs in all legs consist of partly fused ventral and dorsal scoloparia in the proximal femur. The ventral scoloparium neurons can be reliably divided into two groups: the ventral group neurons (VG), which are arranged in a sequentially smaller manner distally, and dorsal group neurons (DG), which simply aggregate in the proximal region near the dorsal scoloparium. All axons of the FCO projected to the ipsilateral half of the respective thoracic ganglion. The VG axons possessed dorso-lateral branches in the motor association neuropile and antero-ventral branches dorso-lateral to the anterior ventral association centre. However, the more proximally the somata were situated, the more medially the main neurites terminated. The DG axons showed some variations: some axons of the distally located neurons possessed dorso-lateral branches and terminated on the boundary region of the mVAC, while the other axons terminated exclusively in the medical ventral association centre (mVAC), including the ventral part, which receives auditory sensory neuron projections. All axons of the dorsal scoloparium neurons projected exclusively into the dorsal part of the mVAC; however, the ventrally located neurons projected more ventrally than did the dorsally located neurons. The above characteristics were nearly identical in the pro- and metathoracic FCOs. These results suggest that the cricket FCO axons are roughly organized in a somatotopic map and are broadly differentiated in their function.

  4. Asymmetric axonal edge guidance: a new paradigm for building oriented neuronal networks.

    Science.gov (United States)

    Renault, Renaud; Durand, Jean-Baptiste; Viovy, Jean-Louis; Villard, Catherine

    2016-06-21

    We present a novel kind of directional axon guides for brain-on-a-chip applications. Contrarily to previous works, the directionality in our design is created by rerouting axons growing in the unwanted direction back to their original compartment while leaving the other growth direction unaffected. This design yields state-of-the-art levels of directionality without the disadvantages of previously reported technologies.

  5. La infección por virus dengue induce la disminución de marcadores de diferenciación en células de neuroblastoma = Dengue virus infection down-regulates differentiation markers in neuroblastoma cells

    Directory of Open Access Journals (Sweden)

    Rincón Forero, Verónica del Pilar

    2011-06-01

    Full Text Available Introducción: cerca del 5% de los pacientes con dengue hemorrágico pueden presentar manifestaciones neurológicas; sin embargo, existe poca información sobre la infección directa por el virus dengue (DENV en neuronas.Objetivo: determinar el papel del fenotipo neuronal en la infección por DENV en células de neuroblastoma SH-SY5Y inducidas o no a la diferenciación con ácido retinoico (AR.Materiales y métodos: células SH-SY5Y fueron inducidas con AR a diferenciarse e infectadas con DENV. Posteriormente se cuantificó la expresión de antígeno viral y de dos marcadores de diferenciación (GAP43 y sinaptofisina. También se evaluó la viabilidad postinfección por la técnica de MTT.Resultados: se encontró que las células diferenciadas son más susceptibles a la infección por DENV, pues se detectó en ellas mayor cantidad de antígeno viral que en las indiferenciadas. A pesar de que el virus indujo muerte celular en ambos tipos de células, la proporción fue mayor en las indiferenciadas (40,3% frente a 21,5%. La infección por DENV en células SH-SY5Y diferenciadas indujo una disminución significativa en la expresión de GAP-43 y sinaptofisina.Conclusiones: los resultados que se presentan permiten sugerir una relación entre la infección viral y la función neuronal, que podría ser importante para esclarecer la patogénesis de las manifestaciones neurológicas durante las formas graves de dengue.

  6. 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

  7. Bridging Physics and Biology Using Resistance and Axons

    Science.gov (United States)

    Dyer, Joshua M.

    2014-11-01

    When teaching physics, it is often difficult to get biology-oriented students to see the relevance of physics.1 A complaint often heard is that biology students are required to take physics for the Medical College Admission Test (MCAT) as part of a "weeding out" process, but that they don't feel like they need physics for biology. Despite this impression held by students, there have been calls for better physics education for future physicians and life scientists.2,3 Research is being performed to improve physics classes and labs by linking topics in biology and physics.4,5 Described here is a laboratory experiment covering the topics of resistance of materials and circuits/Kirchhoff's laws in a biology context with their direct application to neurons, axons, and electrical impulse transmission within animals. This experiment will also demonstrate the mechanism believed to cause multiple sclerosis. The apparatus was designed with low-cost and readily available materials in mind.

  8. 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. PMID:5672003

  9. Human bone marrow mesenchymal stem cell transplantation attenuates axonal injur y in stroke rats

    Institute of Scientific and Technical Information of China (English)

    Yi Xu; Shiwei Du; Xinguang Yu; Xiao Han; Jincai Hou; Hao Guo

    2014-01-01

    Previous studies have shown that transplantation of human bone marrow mesenchymal stem cells promotes neural functional recovery after stroke, but the neurorestorative mechanisms remain largely unknown. We hypothesized that functional recovery of myelinated axons may be one of underlying mechanisms. In this study, an ischemia/reperfusion rat model was established using the middle cerebral artery occlusion method. Rats were used to test the hypothesis that in-travenous transplantation of human bone marrow mesenchymal stem cells through the femoral vein could exert neuroprotective effects against cerebral ischemia via a mechanism associated with the ability to attenuate axonal injury. The results of behavioral tests, infarction volume analysis and immunohistochemistry showed that cerebral ischemia caused severe damage to the myelin sheath and axons. After rats were intravenously transplanted with human bone marrow mesenchymal stem cells, the levels of axon and myelin sheath-related proteins, including mi-crotubule-associated protein 2, myelin basic protein, and growth-associated protein 43, were elevated, infarct volume was decreased and neural function was improved in cerebral ischemic rats. These ifndings suggest that intravenously transplanted human bone marrow mesenchymal stem cells promote neural function. Possible mechanisms underlying these beneifcial effects in-clude resistance to demyelination after cerebral ischemia, prevention of axonal degeneration, and promotion of axonal regeneration.

  10. Enzyme-instructed self-assembly of taxol promotes axonal branching.

    Science.gov (United States)

    Mei, Bin; Miao, Qingqing; Tang, Anming; Liang, Gaolin

    2015-10-14

    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. PMID:26359218

  11. Matrine protects neuro-axon from CNS inflammation-induced injury.

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    Kan, Quan-Cheng; Lv, Peng; Zhang, Xiao-Jian; Xu, Yu-Ming; Zhang, Guang-Xian; Zhu, Lin

    2015-02-01

    Neuro-axonal injury in the central nervous system (CNS) is one of the major pathological hallmarks of experimental autoimmune encephalomyelitis (EAE), an experimental model of multiple sclerosis (MS). Matrine (MAT), a quinolizidine alkaloid derived from the herb Radix Sophorae Flave, has recently been shown to effectively suppress EAE through an anti-inflammatory mechanism. However, whether MAT can also protect myelin/axons from damage is not known. In the present study we show that, while untreated rats developed severe clinical disease, CNS inflammatory demyelination, and axonal damage, these clinical and pathological signs were significantly reduced by MAT treatment. Consistently, MAT treatment reduced the concentration of myelin basic protein in serum and downregulated expression of β-amyloid (Aβ) and B-site APP cleaving enzyme 1 (BACE-1) in the CNS. Further, the CNS of MAT-treated rats exhibited increased expression of brain-derived neurotrophic factor (BDNF), an important factor for neuronal survival and axonal growth. Together, these results demonstrate that MAT effectively prevented neuro-axonal injury, which can likely be attributed to inhibiting risk factors such as BACE-1 and upregulating neuroprotective factors such as BDNF. We conclude that this novel natural reagent, MAT, which effectively protects neuro-axons from CNS inflammation-induced damage, could be a potential candidate for the treatment of neurodegenerative diseases such as MS.

  12. Distinct roles of neuropilin 1 signaling for radial and tangential extension of callosal axons.

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    Hatanaka, Yumiko; Matsumoto, Tomoko; Yanagawa, Yuchio; Fujisawa, Hajime; Murakami, Fujio; Masu, Masayuki

    2009-05-20

    Cortical excitatory neurons migrate from their origin in the ventricular zone (VZ) toward the pial surface. During migration, these neurons exhibit a stellate shape in the intermediate zone (IZ), transform into bipolar cells, and then initiate radial migration, extending a trailing process, which may lead to an axon. Here we examined the role of neuropilin 1 (NRP1) in these developmental events. Both NRP1 mRNA and protein were highly expressed in the IZ, where stellate-shaped cells were located. DiI labeling experiments showed that neuronal migration occurred normally in Nrp1 mutant mice up to embryonic day (E) 14.5, the latest day to which the mutant survives, with only subtle axonal defasciculation. However, interference with Nrp1 signaling at a later stage caused pathfinding errors: when a dominant negative form of Nrp1 was electroporated into the cortical VZ cells at E12.5 or E15.5 and examined perinatally, guidance errors were found in tangential axonal extension toward the midline. In contrast, no significant effect was noted on the migration of cortical excitatory neurons. These findings indicate that NRP1 plays an important role in the guidance of callosal axons originating from cortical excitatory neurons but does not support a role in their migration. Moreover, insofar as radial axonal extension within the cortical plate was unaffected, the present findings imply that molecular mechanisms for the axonal extension of excitatory neurons within the cortical plate are distinct from those in the white matter. PMID:19296474

  13. Axon Branch-Specific Semaphorin-1a Signaling in Drosophila Mushroom Body Development

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    Zwarts, Liesbeth; Goossens, Tim; Clements, Jason; Kang, Yuan Y.; Callaerts, Patrick

    2016-01-01

    Correct wiring of the mushroom body (MB) neuropil in the Drosophila brain involves appropriate positioning of different axonal lobes, as well as the sister branches that develop from individual axons. This positioning requires the integration of various guidance cues provided by different cell types, which help the axons find their final positions within the neuropil. Semaphorins are well-known for their conserved roles in neuronal development and axon guidance. We investigated the role of Sema-1a in MB development more closely. We show that Sema-1a is expressed in the MBs as well as surrounding structures, including the glial transient interhemispheric fibrous ring, throughout development. By loss- and gain-of-function experiments, we show that the MB axons display lobe and sister branch-specific Sema-1a signaling, which controls different aspects of axon outgrowth and guidance. Furthermore, we demonstrate that these effects are modulated by the integration of MB intrinsic and extrinsic Sema-1a signaling pathways involving PlexA and PlexB. Finally, we also show a role for neuronal- glial interaction in Sema-1a dependent β-lobe outgrowth. PMID:27656129

  14. The neural adhesion molecule TAG-1 modulates responses of sensory axons to diffusible guidance signals.

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    Law, Chris O; Kirby, Rebecca J; Aghamohammadzadeh, Soheil; Furley, Andrew J W

    2008-08-01

    When the axons of primary sensory neurons project into the embryonic mammalian spinal cord, they bifurcate and extend rostrocaudally before sending collaterals to specific laminae according to neuronal subclass. The specificity of this innervation has been suggested to be the result both of differential sensitivity to chemorepellants expressed in the ventral spinal cord and of the function of Ig-like neural cell adhesion molecules in the dorsal horn. The relationship between these mechanisms has not been addressed. Focussing on the pathfinding of TrkA+ NGF-dependent axons, we demonstrate for the first time that their axons project prematurely into the dorsal horn of both L1 and TAG-1 knockout mice. We show that axons lacking TAG-1, similar to those lacking L1, are insensitive to wild-type ventral spinal cord (VSC)-derived chemorepellants, indicating that adhesion molecule function is required in the axons, and that this loss of response is explained in part by loss of response to Sema3A. We present evidence that TAG-1 affects sensitivity to Sema3A by binding to L1 and modulating the endocytosis of the L1/neuropilin 1 Sema3A receptor complex. However, TAG-1 appears to affect sensitivity to other VSC-derived chemorepellants via an L1-independent mechanism. We suggest that this dependence of chemorepellant sensitivity on the functions of combinations of adhesion molecules is important to ensure that axons project via specific pathways before extending to their final targets. PMID:18550718

  15. Propagation of action potentials along complex axonal trees. Model and implementation.

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    Manor, Y; Gonczarowski, J; Segev, I

    1991-01-01

    Axonal trees are typically morphologically and physiologically complicated structures. Because of this complexity, axonal trees show a large repertoire of behavior: from transmission lines with delay, to frequency filtering devices in both temporal and spatial domains. Detailed theoretical exploration of the electrical behavior of realistically complex axonal trees is notably lacking, mainly because of the absence of a simple modeling tool. AXONTREE is an attempt to provide such a simulator. It is written in C for the SUN workstation and implements both a detailed compartmental modeling of Hodgkin and Huxley-like kinetics, and a more abstract, event-driven, modeling approach. The computing module of AXONTREE is introduced together with its input/output features. These features allow graphical construction of arbitrary trees directly on the computer screen, and superimposition of the results on the simulated structure. Several numerical improvements that increase the computational efficiency by a factor of 5-10 are presented; most notable is a novel method of dynamic lumping of the modeled tree into simpler representations ("equivalent cables"). AXONTREE's performance is examined using a reconstructed terminal of an axon from a Y cell in cat visual cortex. It is demonstrated that realistically complicated axonal trees can be handled efficiently. The application of AXONTREE for the study of propagation delays along axonal trees is presented in the companion paper (Manor et al., 1991). Images FIGURE 4 PMID:1777566

  16. BDNF promotes target innervation of Xenopus mandibular trigeminal axons in vivo

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    Ishibashi Shoko

    2007-05-01

    Full Text Available Abstract Background Trigeminal nerves consist of ophthalmic, maxillary, and mandibular branches that project to distinct regions of the facial epidermis. In Xenopus embryos, the mandibular branch of the trigeminal nerve extends toward and innervates the cement gland in the anterior facial epithelium. The cement gland has previously been proposed to provide a short-range chemoattractive signal to promote target innervation by mandibular trigeminal axons. Brain derived neurotrophic factor, BDNF is known to stimulate axon outgrowth and branching. The goal of this study is to determine whether BDNF functions as the proposed target recognition signal in the Xenopus cement gland. Results We found that the cement gland is enriched in BDNF mRNA transcripts compared to the other neurotrophins NT3 and NT4 during mandibular trigeminal nerve innervation. BDNF knockdown in Xenopus embryos or specifically in cement glands resulted in the failure of mandibular trigeminal axons to arborise or grow into the cement gland. BDNF expressed ectodermal grafts, when positioned in place of the cement gland, promoted local trigeminal axon arborisation in vivo. Conclusion BDNF is necessary locally to promote end stage target innervation of trigeminal axons in vivo, suggesting that BDNF functions as a short-range signal that stimulates mandibular trigeminal axon arborisation and growth into the cement gland.

  17. A Simple Method for 3D Analysis of Immunolabeled Axonal Tracts in a Transparent Nervous System

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    Morgane Belle

    2014-11-01

    Full Text Available Clearing techniques have been developed to transparentize mouse brains, thereby preserving 3D structure, but their complexity has limited their use. Here, we show that immunolabeling of axonal tracts followed by optical clearing with solvents (3DISCO and light-sheet microscopy reveals brain connectivity in mouse embryos and postnatal brains. We show that the Robo3 receptor is selectively expressed by medial habenula axons forming the fasciculus retroflexus (FR and analyzed the development of this commissural tract in mutants of the Slit/Robo and DCC/Netrin pathways. Netrin-1 and DCC are required to attract FR axons to the midline, but the two mutants exhibit specific and heterogeneous axon guidance defects. Moreover, floor-plate-specific deletion of Slit ligands with a conditional Slit2 allele perturbs not only midline crossing by FR axons but also their anteroposterior distribution. In conclusion, this method represents a unique and powerful imaging tool to study axonal connectivity in mutant mice.

  18. Synaptic gating at axonal branches, and sharp-wave ripples with replay: a simulation study.

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    Vladimirov, Nikita; Tu, Yuhai; Traub, Roger D

    2013-11-01

    Mechanisms of place cell replay occurring during sharp-wave ripples (SPW-Rs) remain obscure due to the fact that ripples in vitro depend on non-synaptic mechanisms, presumably via axo-axonal gap junctions between pyramidal cells. We suggest a model of in vivo SPW-Rs in which synaptic excitatory post-synaptic potentials (EPSPs) control the axonal spiking of cells in SPW-Rs: ripple activity remains hidden in the network of axonal collaterals (connected by gap junctions) due to conduction failures, unless there is a sufficient dendritic EPSP. The EPSP brings the axonal branching point to threshold, and action potentials from the collateral start to propagate to the soma and to the distal axon. The model coherently explains multiple experimental data on SPW-Rs, both in vitro and in vivo. The mechanism of synaptic gating leads to the following implication: a sequence of pyramidal cells can be replayed at ripple frequency by the superposition of subthreshold dendritic EPSPs and ripple activity in the axonal plexus. Replay is demonstrated in both forward and reverse directions. We discuss several testable predictions. In general, the mechanism of synaptic gating suggests that pyramidal cells under certain conditions can act like a transistor.

  19. Effects of medium flow on axon growth with or without nerve growth factor.

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    Kumamoto, Junichi; Kitahata, Hiroyuki; Goto, Makiko; Nagayama, Masaharu; Denda, Mitsuhiro

    2015-09-11

    Axon growth is a crucial process in regeneration of damaged nerves. On the other hand, elongation of nerve fibers in the epidermis has been observed in skin of atopic dermatitis patients. Thus, regulation of nerve fiber extension might be an effective strategy to accelerate nerve regeneration and/or to reduce itching in pruritus dermatosis. We previously demonstrated that neurons and epidermal keratinocytes similarly contain multiple receptors that are activated by various environmental factors, and in particular, keratinocytes are influenced by shear stress. Thus, in the present study, we evaluated the effects of micro-flow of the medium on axon growth in the presence or absence of nerve growth factor (NGF), using cultured dorsal-root-ganglion (DRG) cells. The apparatus, AXIS™, consists of two chambers connected by a set of microgrooves, through which signaling molecules and axons, but not living cells, can pass. When DRG cells were present in chamber 1, NGF was present in chamber 2, and micro-flow was directed from chamber 1 to chamber 2, axon growth was significantly increased compared with other conditions. Acceleration of axon growth in the direction of the micro-flow was also observed in the absence of NGF. These results suggest that local micro-flow might significantly influence axon growth. PMID:26212442

  20. Extra-neurohypophyseal axonal projections from individual vasopressin-containing magnocellular neurons in rat hypothalamus

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    Vito Salvador Hernandez

    2015-10-01

    Full Text Available Conventional neuroanatomical, immunohistochemical techniques and electrophysiological recording, as well as in vitro labeling methods may fail to detect long range extra-neurohypophyseal-projecting axons from vasopressin (AVP-containing magnocellular neurons (magnocells in the hypothalamic paraventricular nucleus (PVN. Here, we used in vivo extracellular recording, juxtacellular labeling, post hoc anatomo-immunohistochemical analysis and camera lucida reconstruction to address this question. We demonstrate that all well-labeled AVP immunopositive neurons inside the PVN possess main axons joining the tract of Greving and multi-axon-like processes, as well as axonal collaterals branching very near to the somata, which project to extra-neurohypophyseal regions. The detected regions in this study include the medial and lateral preoptical area, suprachiasmatic nucleus, lateral habenula, medial and central amygdala and the conducting systems, such as stria medullaris, the fornix and the internal capsule. Expression of vesicular glutamate transporter 2 was observed in axon-collaterals. These results, in congruency with several previous reports in the literature, provided unequivocal evidence that AVP magnocells have an uncommon feature of possessing multiple axon-like processes emanating from somata or proximal dendrites. Furthermore, the long-range non-neurohypophyseal projections are more common than an occasional phenomenon as previously thought.

  1. Diverse roles for Wnt7a in ventral midbrain neurogenesis and dopaminergic axon morphogenesis.

    Science.gov (United States)

    Fernando, Chathurini V; Kele, Julianna; Bye, Christopher R; Niclis, Jonathan C; Alsanie, Walaa; Blakely, Brette D; Stenman, Jan; Turner, Brad J; Parish, Clare L

    2014-09-01

    During development of the central nervous system, trophic, together with genetic, cues dictate the balance between cellular proliferation and differentiation. Subsequent to the birth of new neurons, additional intrinsic and extrinsic signals regulate the connectivity of these cells. While a number of regulators of ventral midbrain (VM) neurogenesis and dopaminergic (DA) axon guidance are known, we identify a number of novel roles for the secreted glycoprotein, Wnt7a, in this context. We demonstrate a temporal and spatial expression of Wnt7a in the VM, indicative of roles in neurogenesis, differentiation, and axonal growth and guidance. In primary VM cultures, and validated in Wnt7a-deficient mice, we show that the early expression within the VM is important for regulating VM progenitor proliferation, cell cycle progression, and cell survival, thereby dictating the number of midbrain Nurr1 precursors and DA neurons. During early development of the midbrain DA pathways, Wnt7a promotes axonal elongation and repels DA neurites out of the midbrain. Later, Wnt7a expression in the VM midline suggests a role in preventing axonal crossing while expression in regions flanking the medial forebrain bundle (thalamus and hypothalamus) ensured appropriate trajectory of DA axons en route to their forebrain targets. We show that the effects of Wnt7a in VM development are mediated, at least in part, by the β-catenin/canonical pathways. Together, these findings identify Wnt7a as a new regulator of VM neurogenesis and DA axon growth and guidance.

  2. Pioneer Axon Navigation Is Controlled by AEX-3, a Guanine Nucleotide Exchange Factor for RAB-3 in Caenorhabditis elegans.

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    Bhat, Jaffar M; Hutter, Harald

    2016-07-01

    Precise and accurate axon tract formation is an essential aspect of brain development. This is achieved by the migration of early outgrowing axons (pioneers) allowing later outgrowing axons (followers) to extend toward their targets in the embryo. In Caenorhabditis elegans the AVG neuron pioneers the right axon tract of the ventral nerve cord, the major longitudinal axon tract. AVG is essential for the guidance of follower axons and hence organization of the ventral nerve cord. In an enhancer screen for AVG axon guidance defects in a nid-1/Nidogen mutant background, we isolated an allele of aex-3 aex-3 mutant animals show highly penetrant AVG axon navigation defects. These defects are dependent on a mutation in nid-1/Nidogen, a basement membrane component. Our data suggest that AEX-3 activates RAB-3 in the context of AVG axon navigation. aex-3 genetically acts together with known players of vesicular exocytosis: unc-64/Syntaxin, unc-31/CAPS, and ida-1/IA-2. Furthermore our genetic interaction data suggest that AEX-3 and the UNC-6/Netrin receptor UNC-5 act in the same pathway, suggesting AEX-3 might regulate the trafficking and/or insertion of UNC-5 at the growth cone to mediate the proper guidance of the AVG axon. PMID:27116976

  3. Two different immunostaining patterns of beta-amyloid precursor protein (APP) may distinguish traumatic from nontraumatic axonal injury.

    Science.gov (United States)

    Hayashi, Takahito; Ago, Kazutoshi; Nakamae, Takuma; Higo, Eri; Ogata, Mamoru

    2015-09-01

    Immunostaining for beta-amyloid precursor protein (APP) is recognized as an effective tool for detecting traumatic axonal injury, but it also detects axonal injury due to ischemic or other metabolic causes. Previously, we reported two different patterns of APP staining: labeled axons oriented along with white matter bundles (pattern 1) and labeled axons scattered irregularly (pattern 2) (Hayashi et al. (Leg Med (Tokyo) 11:S171-173, 2009). In this study, we investigated whether these two patterns are consistent with patterns of trauma and hypoxic brain damage, respectively. Sections of the corpus callosum from 44 cases of blunt head injury and equivalent control tissue were immunostained for APP. APP was detected in injured axons such as axonal bulbs and varicose axons in 24 of the 44 cases of head injuries that also survived for three or more hours after injury. In 21 of the 24 APP-positive cases, pattern 1 alone was observed in 14 cases, pattern 2 alone was not observed in any cases, and both patterns 1 and 2 were detected in 7 cases. APP-labeled injured axons were detected in 3 of the 44 control cases, all of which were pattern 2. These results suggest that pattern 1 indicates traumatic axonal injury, while pattern 2 results from hypoxic insult. These patterns may be useful to differentiate between traumatic and nontraumatic axonal injuries.

  4. Differential subcellular recruitment of monoacylglycerol lipase generates spatial specificity of 2-arachidonoyl glycerol signaling during axonal pathfinding

    Science.gov (United States)

    Keimpema, Erik; Barabas, Klaudia; Morozov, Yury M.; Tortoriello, Giuseppe; Torii, Masaaki; Cameron, Gary; Yanagawa, Yuchio; Watanabe, Masahiko; Mackie, Ken; Harkany, Tibor

    2010-01-01

    Endocannabinoids, particularly 2-arachidonoyl glycerol (2-AG), impact the directional turning and motility of a developing axon by activating CB1 cannabinoid receptors (CB1Rs) in its growth cone. Recent findings posit that sn-1-diacylglycerol lipases (DAGLα/β) synthesize 2-AG in the motile axon segment of developing pyramidal cells. Coincident axonal targeting of CB1Rs and DAGLs prompts the hypothesis that autocrine 2-AG signaling facilitates axonal outgrowth. However, DAGLs alone are insufficient to account for the spatial specificity and dynamics of 2-AG signaling. Therefore, we hypothesized that local 2-AG degradation by monoacylglycerol lipase (MGL) must play a role. We determined how subcellular recruitment of MGL is temporally and spatially restricted to establish 2-AG’s signaling competence during axonal growth. MGL is expressed in central and peripheral axons of the fetal nervous system by embryonic day 12.5. MGL coexists with DAGLα and CB1Rs in corticofugal axons of pyramidal cells. Here, MGL and DAGLα undergo differential axonal targeting with MGL being excluded from the motile neurite tip. Thus, spatially-confined MGL activity generates a 2-AG-sensing microdomain and configures 2-AG signaling to promote axonal growth. Once synaptogenesis commences, MGL disperses in stationary growth cones. MGL’s axonal polarity is maintained by differential proteasomal degradation since inhibiting the ubiquitin proteasome system also induces axonal MGL redistribution. Since MGL inactivation drives a CB1R-dependent axonal growth response we conclude that 2-AG may act as a focal protrusive signal for developing neurons and whose regulated metabolism is critical for attaining correct axonal complexity. PMID:20962221

  5. Sociedad por Acciones Simplificada

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    Carlos Andrés Arcila Salazar

    2009-06-01

    Full Text Available En Colombia, aspectos como la responsabilidad limitada; supresión de la llamada doctrina de ultra vires; duración ilimitada; eliminación de la regla, una acción, un voto; remedios al abuso de los derechos; posibilidad de eliminar prohibiciones a los administradores, libertad de establecer restricciones para la transferencia de acciones y la simplificación de los procedimientos de fusión; son inviables bajo nuestra legislación. Sin embargo, la Ley 1258 de 2008, ha incorporado al derecho societario colombiano un nuevo tipo societario híbrido, llamado “Sociedad por Acciones Simplificada”. Esta forma societaria híbrida se basa en un principio básico: garantizar amplia libertad a los empresarios en la estructuración de sus relaciones a través de disposiciones contractuales. La S.A.S. provee a los empresarios significativa flexibilidad contractual, a la vez que preserva beneficios como la limitación de la responsabilidad.

  6. Sociedad por Acciones Simplificada

    Directory of Open Access Journals (Sweden)

    Carlos Andrés Arcila Salazar

    2009-07-01

    Full Text Available En Colombia, aspectos como la responsabilidad limitada; supresión de la llamada doctrina de ultra vires; duración ilimitada; eliminación de la regla, una acción, un voto; remedios al abuso de los derechos; posibilidad de eliminar prohibiciones a los administradores, libertad de establecer restricciones para la transferencia de acciones y la simplificación de los procedimientos de fusión; son inviables bajo nuestra legislación. Sin embargo, la Ley 1258 de 2008, ha incorporado al derecho societario colombiano un nuevo tipo societario híbrido, llamado “Sociedad por Acciones Simplificada”. Esta forma societaria híbrida se basa en un principio básico: garantizar amplia libertad a los empresarios en la estructuración de sus relaciones a través de disposiciones contractuales. La S.A.S. provee a los empresarios significativa flexibilidad contractual, a la vez que preserva beneficios como la limitación de la responsabilidad.

  7. Nefropatía por contraste en el síndrome coronario agudo

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    Mariana Carnevalini

    2011-10-01

    Full Text Available 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 de cinecoronariografía (CCG. Se realizó un estudio de cohorte retrospectivo. Se incluyeron pacientes consecutivos cursando SCA estudiados con CCG dentro de las 72 horas de su admisión. Se definió NIC al aumento del 25% del valor de creatinina a las 48 h sobre el nivel basal de ingreso. El período de inclusión fue entre el 1° de enero de 2004 hasta el 30 de junio de 2010. Se analizaron 125 casos. La incidencia de NIC fue del 10.4% (n = 13. En el análisis multivariado, los factores asociados independientemente a su desarrollo fueron la edad [OR 1.05 (IC 95% 1.004 - 1.11 p = 0.034], la angioplastia a múltiple vaso [OR 2.2 (IC 95% 1.07 - 4.8, p = 0.03] y el volumen de contraste utilizado [OR 1.007 (IC 95% 1.001 - 1.01, p = 0.014].

  8. Comparison of electrical responses of terminals, axons, and somata of a peptidergic neurosecretory system.

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    Nagano, M; Cooke, I M

    1987-03-01

    Spontaneous and evoked electrical activity was recorded intracellularly from somata, axons, and terminal dilatations of an isolated peptidergic neurosecretory system, the X-organ-sinus gland, of the crabs Cardisoma carnifex and Podophthalmus vigil in order to compare their electrical characteristics. Spontaneous impulse activity was present in most penetrations and included irregular and pacemaker-like firing, as well as patterned activity (bursting). Extracellular recording showed that spontaneous impulses and bursting originate in a proximal region of the axon tract. Somata vary from being electrically nonresponsive to having overshooting impulses with a relatively slow rate of rise. Overshooting impulses were consistently recorded from axons and terminals. Regional differences include (1) a longer action potential duration in terminals, (2) ability of axons and terminals but not somata to sustain repetitive firing, (3) presence of depolarizing afterpotentials in axons but of hyperpolarizing afterpotentials in somata and terminals, and (4) occurrence of impulse broadening during repetitive firing in some terminals but not in axons or somata. Somata and terminals sustained reduced and slowed, but regenerative impulses in nominally Na-free saline and showed alterations of waveform in nominally Ca-free salines, while axons showed no regenerative responses in Na-free saline and no change of impulse form in Ca-free saline. Terminal responses in the presence of tetraethylammonium chloride (TEA) (50 mM) or Ba (50 mM) exhibited long depolarized plateaus, while impulses of somata were much less prolonged. Bursts often took the form of impulses superimposed on a depolarized plateau. Bursts could be evoked by single stimuli applied to the axon tract but not by current passed intracellularly. After addition of TTX, axon tract stimulation evoked plateaus without superimposed impulses. Terminals exhibit specialization of their electrical responses by comparison to axons and

  9. p250GAP is a novel player in the Cdh1-APC/Smurf1 pathway of axon growth regulation.

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    Madhuvanthi Kannan

    Full Text Available Axon growth is an essential process during brain development. The E3 ubiquitin ligase Cdh1-APC has emerged as a critical regulator of intrinsic axon growth control. Here, we identified the RhoGAP p250GAP as a novel interactor of the E3 ubiquitin ligase Cdh1-APC and found that p250GAP promotes axon growth downstream of Cdh1-APC. We also report that p250GAP undergoes non-proteolytic ubiquitination and associates with the Cdh1 substrate Smurf1 to synergistically regulate axon growth. Finally, we found that in vivo knockdown of p250GAP in the developing cerebellar cortex results in impaired migration and axonal growth. Taken together, our data indicate that Cdh1-APC together with the RhoA regulators p250GAP and Smurf1 controls axon growth in the mammalian brain.

  10. Axonal patterns and targets of dA1 interneurons in the chick hindbrain.

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    Kohl, Ayelet; Hadas, Yoav; Klar, Avihu; Sela-Donenfeld, Dalit

    2012-04-25

    Hindbrain dorsal interneurons that comprise the rhombic lip relay sensory information and coordinate motor outputs. The progenitor dA1 subgroup of interneurons, which is formed along the dorsal-most region of the caudal rhombic lip, gives rise to the cochlear and precerebellar nuclei. These centers project sensory inputs toward upper-brain regions. The fundamental role of dA1 interneurons in the assembly and function of these brainstem nuclei is well characterized. However, the precise en route axonal patterns and synaptic targets of dA1 interneurons are not clear as of yet. Novel genetic tools were used to label dA1 neurons and trace their axonal trajectories and synaptic connections at various stages of chick embryos. Using dA1-specific enhancers, two contralateral ascending axonal projection patterns were identified; one derived from rhombomeres 6-7 that elongated in the dorsal funiculus, while the other originated from rhombomeres 2-5 and extended in the lateral funiculus. Targets of dA1 axons were followed at later stages using PiggyBac-mediated DNA transposition. dA1 axons were found to project and form synapses in the auditory nuclei and cerebellum. Investigation of mechanisms that regulate the patterns of dA1 axons revealed a fundamental role of Lim-homeodomain (HD) proteins. Switch in the expression of the specific dA1 Lim-HD proteins Lhx2/9 into Lhx1, which is typically expressed in dB1 interneurons, modified dA1 axonal patterns to project along the routes of dB1 subgroup. Together, the results of this research provided new tools and knowledge to the assembly of trajectories and connectivity of hindbrain dA1 interneurons and of molecular mechanisms that control these patterns.

  11. Protein 4.1B contributes to the organization of peripheral myelinated axons.

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    Carmen Cifuentes-Diaz

    Full Text Available Neurons are characterized by extremely long axons. This exceptional cell shape is likely to depend on multiple factors including interactions between the cytoskeleton and membrane proteins. In many cell types, members of the protein 4.1 family play an important role in tethering the cortical actin-spectrin cytoskeleton to the plasma membrane. Protein 4.1B is localized in myelinated axons, enriched in paranodal and juxtaparanodal regions, and also all along the internodes, but not at nodes of Ranvier where are localized the voltage-dependent sodium channels responsible for action potential propagation. To shed light on the role of protein 4.1B in the general organization of myelinated peripheral axons, we studied 4.1B knockout mice. These mice displayed a mildly impaired gait and motility. Whereas nodes were unaffected, the distribution of Caspr/paranodin, which anchors 4.1B to the membrane, was disorganized in paranodal regions and its levels were decreased. In juxtaparanodes, the enrichment of Caspr2, which also interacts with 4.1B, and of the associated TAG-1 and Kv1.1, was absent in mutant mice, whereas their levels were unaltered. Ultrastructural abnormalities were observed both at paranodes and juxtaparanodes. Axon calibers were slightly diminished in phrenic nerves and preterminal motor axons were dysmorphic in skeletal muscle. βII spectrin enrichment was decreased along the axolemma. Electrophysiological recordings at 3 post-natal weeks showed the occurrence of spontaneous and evoked repetitive activity indicating neuronal hyperexcitability, without change in conduction velocity. Thus, our results show that in myelinated axons 4.1B contributes to the stabilization of membrane proteins at paranodes, to the clustering of juxtaparanodal proteins, and to the regulation of the internodal axon caliber.

  12. Primary neuron culture for nerve growth and axon guidance studies in zebrafish (Danio rerio.

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    Zheyan Chen

    Full Text Available Zebrafish (Danio rerio is a widely used model organism in genetics and developmental biology research. Genetic screens have proven useful for studying embryonic development of the nervous system in vivo, but in vitro studies utilizing zebrafish have been limited. Here, we introduce a robust zebrafish primary neuron culture system for functional nerve growth and guidance assays. Distinct classes of central nervous system neurons from the spinal cord, hindbrain, forebrain, and retina from wild type zebrafish, and fluorescent motor neurons from transgenic reporter zebrafish lines, were dissociated and plated onto various biological and synthetic substrates to optimize conditions for axon outgrowth. Time-lapse microscopy revealed dynamically moving growth cones at the tips of extending axons. The mean rate of axon extension in vitro was 21.4±1.2 µm hr(-1 s.e.m. for spinal cord neurons, which corresponds to the typical ∼0.5 mm day(-1 growth rate of nerves in vivo. Fluorescence labeling and confocal microscopy demonstrated that bundled microtubules project along axons to the growth cone central domain, with filamentous actin enriched in the growth cone peripheral domain. Importantly, the growth cone surface membrane expresses receptors for chemotropic factors, as detected by immunofluorescence microscopy. Live-cell functional assays of axon extension and directional guidance demonstrated mammalian brain-derived neurotrophic factor (BDNF-dependent stimulation of outgrowth and growth cone chemoattraction, whereas mammalian myelin-associated glycoprotein inhibited outgrowth. High-resolution live-cell Ca(2+-imaging revealed local elevation of cytoplasmic Ca(2+ concentration in the growth cone induced by BDNF application. Moreover, BDNF-induced axon outgrowth, but not basal outgrowth, was blocked by treatments to suppress cytoplasmic Ca(2+ signals. Thus, this primary neuron culture model system may be useful for studies of neuronal development

  13. Network structure implied by initial axon outgrowth in rodent cortex: empirical measurement and models.

    Science.gov (United States)

    Cahalane, Diarmuid J; Clancy, Barbara; Kingsbury, Marcy A; Graf, Ethan; Sporns, Olaf; Finlay, Barbara L

    2011-01-11

    The developmental mechanisms by which the network organization of the adult cortex is established are incompletely understood. Here we report on empirical data on the development of connections in hamster isocortex and use these data to parameterize a network model of early cortical connectivity. Using anterograde tracers at a series of postnatal ages, we investigate the growth of connections in the early cortical sheet and systematically map initial axon extension from sites in anterior (motor), middle (somatosensory) and posterior (visual) cortex. As a general rule, developing axons extend from all sites to cover relatively large portions of the cortical field that include multiple cortical areas. From all sites, outgrowth is anisotropic, covering a greater distance along the medial/lateral axis than along the anterior/posterior axis. These observations are summarized as 2-dimensional probability distributions of axon terminal sites over the cortical sheet. Our network model consists of nodes, representing parcels of cortex, embedded in 2-dimensional space. Network nodes are connected via directed edges, representing axons, drawn according to the empirically derived anisotropic probability distribution. The networks generated are described by a number of graph theoretic measurements including graph efficiency, node betweenness centrality and average shortest path length. To determine if connectional anisotropy helps reduce the total volume occupied by axons, we define and measure a simple metric for the extra volume required by axons crossing. We investigate the impact of different levels of anisotropy on network structure and volume. The empirically observed level of anisotropy suggests a good trade-off between volume reduction and maintenance of both network efficiency and robustness. Future work will test the model's predictions for connectivity in larger cortices to gain insight into how the regulation of axonal outgrowth may have evolved to achieve efficient

  14. Endoplasmic reticulum sorting and kinesin-1 command the targeting of axonal GABAB receptors.

    Directory of Open Access Journals (Sweden)

    Viviana Valdés

    Full Text Available In neuronal cells the intracellular trafficking machinery controls the availability of neurotransmitter receptors at the plasma membrane, which is a critical determinant of synaptic strength. Metabotropic γ amino-butyric acid (GABA type B receptors (GABA(BRs are neurotransmitter receptors that modulate synaptic transmission by mediating the slow and prolonged responses to GABA. GABA(BRs are obligatory heteromers constituted by two subunits, GABA(BR1 and GABA(BR2. GABA(BR1a and GABA(BR1b are the most abundant subunit variants. GABA(BR1b is located in the somatodendritic domain whereas GABA(BR1a is additionally targeted to the axon. Sushi domains located at the N-terminus of GABA(BR1a constitute the only difference between both variants and are necessary and sufficient for axonal targeting. The precise targeting machinery and the organelles involved in sorting and transport have not been described. Here we demonstrate that GABA(BRs require the Golgi apparatus for plasma membrane delivery but that axonal sorting and targeting of GABA(BR1a operate in a pre-Golgi compartment. In the axon GABA(BR1a subunits are enriched in the endoplasmic reticulum (ER, and their dynamic behavior and colocalization with other secretory organelles like the ER-to-Golgi intermediate compartment (ERGIC suggest that they employ a local secretory route. The transport of axonal GABA(BR1a is microtubule-dependent and kinesin-1, a molecular motor of the kinesin family, determines axonal localization. Considering that progression of GABA(BRs through the secretory pathway is regulated by an ER retention motif our data contribute to understand the role of the axonal ER in non-canonical sorting and targeting of neurotransmitter receptors.

  15. Filtration coefficient of the axon membrane as measured with hydrostatic and osmotic methods.

    Science.gov (United States)

    Vargas, F F

    1968-01-01

    The hydraulic conductivity of the membranes surrounding the giant axon of the squid, Dosidicus gigas, was measured. In some axons the axoplasm was partially removed by suction. Perfusion was then established by insertion of a second pipette. In other axons the axoplasm was left intact and only one pipette was inserted. In both groups hydrostatic pressure was applied by means of a water column in a capillary manometer. Displacement of the meniscus in time gave the rate of fluid flowing across the axon sheath. In both groups osmotic differences across the membrane were established by the addition of a test molecule to the external medium which was seawater. The hydraulic conductivity determined by application of hydrostatic pressure was 10.6 +/- 0.8.10(-8) cm/sec cm H(2)O in perfused axons and 3.2 +/- 0.6.10(-8) cm/sec cm H(2)O in intact axons. When the driving force was an osmotic pressure gradient the conductivity was 4.5 +/- 0.6 x 10(-10) cm/sec cm H(2)O and 4.8 +/- 0.9 x 10(-10) cm/sec cm H(2)O in perfused and intact axons, respectively. A comparable result was found when the internal solution was made hyperosmotic. The fluid flow was a linear function of the hydrostatic pressure up to 70 cm of water. Glycerol outflux and membrane conductance were increased 1.6 and 1.1 times by the application of hydrostatic pressure. These increments do not give an explanation of the difference between the filtration coefficients. Other possible explanations are suggested and discussed. PMID:5642470

  16. Rescuing axons from degeneration does not affect retinal ganglion cell death

    Directory of Open Access Journals (Sweden)

    S. de Lima

    2016-01-01

    Full Text Available After a traumatic injury to the central nervous system, the distal stumps of axons undergo Wallerian degeneration (WD, an event that comprises cytoskeleton and myelin breakdown, astrocytic gliosis, and overexpression of proteins that inhibit axonal regrowth. By contrast, injured neuronal cell bodies show features characteristic of attempts to initiate the regenerative process of elongating their axons. The main molecular event that leads to WD is an increase in the intracellular calcium concentration, which activates calpains, calcium-dependent proteases that degrade cytoskeleton proteins. The aim of our study was to investigate whether preventing axonal degeneration would impact the survival of retinal ganglion cells (RGCs after crushing the optic nerve. We observed that male Wistar rats (weighing 200-400 g; n=18 treated with an exogenous calpain inhibitor (20 mM administered via direct application of the inhibitor embedded within the copolymer resin Evlax immediately following optic nerve crush showed a delay in the onset of WD. This delayed onset was characterized by a decrease in the number of degenerated fibers (P<0.05 and an increase in the number of preserved fibers (P<0.05 4 days after injury. Additionally, most preserved fibers showed a normal G-ratio. These results indicated that calpain inhibition prevented the degeneration of optic nerve fibers, rescuing axons from the process of axonal degeneration. However, analysis of retinal ganglion cell survival demonstrated no difference between the calpain inhibitor- and vehicle-treated groups, suggesting that although the calpain inhibitor prevented axonal degeneration, it had no effect on RGC survival after optic nerve damage.

  17. The C-terminal binding protein (CTBP-1) regulates dorsal SMD axonal morphology in Caenorhabditis elegans.

    Science.gov (United States)

    Reid, A; Sherry, T J; Yücel, D; Llamosas, E; Nicholas, H R

    2015-12-17

    C-terminal binding proteins (CtBPs) are transcriptional co-repressors which cooperate with a variety of transcription factors to repress gene expression. Caenorhabditis elegans CTBP-1 expression has been observed in the nervous system and hypodermis. In C. elegans, CTBP-1 regulates several processes including Acute Functional Tolerance to ethanol and functions in the nervous system to modulate both lifespan and expression of a lipase gene called lips-7. Incorrect structure and/or function of the nervous system can lead to behavioral changes. Here, we demonstrate reduced exploration behavior in ctbp-1 mutants. Our examination of a subset of neurons involved in regulating locomotion revealed that the axonal morphology of dorsal SMD (SMDD) neurons is altered in ctbp-1 mutants at the fourth larval (L4) stage. Expressing CTBP-1 under the control of the endogenous ctbp-1 promoter rescued both the exploration behavior phenotype and defective SMDD axon structure in ctbp-1 mutants at the L4 stage. Interestingly, the pre-synaptic marker RAB-3 was found to localize to the mispositioned portion of SMDD axons in a ctbp-1 mutant. Further analysis of SMDD axonal morphology at days 1, 3 and 5 of adulthood revealed that the number of ctbp-1 mutants showing an SMDD axonal morphology defect increases in early adulthood and the observed defect appears to be qualitatively more severe. CTBP-1 is prominently expressed in the nervous system with weak expression detected in the hypodermis. Surprisingly, solely expressing CTBP-1a in the nervous system or hypodermis did not restore correct SMDD axonal structure in a ctbp-1 mutant. Our results demonstrate a role for CTBP-1 in exploration behavior and the regulation of SMDD axonal morphology in C. elegans.

  18. Short-term peripheral nerve stimulation ameliorates axonal dysfunction after spinal cord injury.

    Science.gov (United States)

    Lee, Michael; Kiernan, Matthew C; Macefield, Vaughan G; Lee, Bonne B; Lin, Cindy S-Y

    2015-05-01

    There is accumulating evidence that peripheral motor axons deteriorate following spinal cord injury (SCI). Secondary axonal dysfunction can exacerbate muscle atrophy, contribute to peripheral neuropathies and neuropathic pain, and lead to further functional impairment. In an attempt to ameliorate the adverse downstream effects that developed following SCI, we investigated the effects of a short-term peripheral nerve stimulation (PNS) program on motor axonal excitability in 22 SCI patients. Axonal excitability studies were undertaken in the median and common peroneal nerves (CPN) bilaterally before and after a 6-wk unilateral PNS program. PNS was delivered percutaneously over the median nerve at the wrist and CPN around the fibular head, and the compound muscle action potential (CMAP) from the abductor pollicis brevis and tibialis anterior was recorded. Stimulus intensity was above motor threshold, and pulses (450 μs) were delivered at 100 Hz with a 2-s on/off cycle for 30 min 5 days/wk. SCI patients had consistently high thresholds with a reduced CMAP consistent with axonal loss; in some patients the peripheral nerves were completely inexcitable. Nerve excitability studies revealed profound changes in membrane potential, with a "fanned-in" appearance in threshold electrotonus, consistent with membrane depolarization, and significantly reduced superexcitability during the recovery cycle. These membrane dysfunctions were ameliorated after 6 wk of PNS, which produced a significant hyperpolarizing effect. The contralateral, nonstimulated nerves remained depolarized. Short-term PNS reversed axonal dysfunction following SCI, may provide an opportunity to prevent chronic changes in axonal and muscular function, and may improve rehabilitation outcomes. PMID:25787956

  19. A multi-component model of the developing retinocollicular pathway incorporating axonal and synaptic growth.

    Directory of Open Access Journals (Sweden)

    Keith B Godfrey

    2009-12-01

    Full Text Available During development, neurons extend axons to different brain areas and produce stereotypical patterns of connections. The mechanisms underlying this process have been intensively studied in the visual system, where retinal neurons form retinotopic maps in the thalamus and superior colliculus. The mechanisms active in map formation include molecular guidance cues, trophic factor release, spontaneous neural activity, spike-timing dependent plasticity (STDP, synapse creation and retraction, and axon growth, branching and retraction. To investigate how these mechanisms interact, a multi-component model of the developing retinocollicular pathway was produced based on phenomenological approximations of each of these mechanisms. Core assumptions of the model were that the probabilities of axonal branching and synaptic growth are highest where the combined influences of chemoaffinity and trophic factor cues are highest, and that activity-dependent release of trophic factors acts to stabilize synapses. Based on these behaviors, model axons produced morphologically realistic growth patterns and projected to retinotopically correct locations in the colliculus. Findings of the model include that STDP, gradient detection by axonal growth cones and lateral connectivity among collicular neurons were not necessary for refinement, and that the instructive cues for axonal growth appear to be mediated first by molecular guidance and then by neural activity. Although complex, the model appears to be insensitive to variations in how the component developmental mechanisms are implemented. Activity, molecular guidance and the growth and retraction of axons and synapses are common features of neural development, and the findings of this study may have relevance beyond organization in the retinocollicular pathway.

  20. Axon degeneration and PGC-1α-mediated protection in a zebrafish model of α-synuclein toxicity

    Directory of Open Access Journals (Sweden)

    Kelley C. O’Donnell

    2014-05-01

    Full Text Available α-synuclein (aSyn expression is implicated in neurodegenerative processes, including Parkinson’s disease (PD and dementia with Lewy bodies (DLB. In animal models of these diseases, axon pathology often precedes cell death, raising the question of whether aSyn has compartment-specific toxic effects that could require early and/or independent therapeutic intervention. The relevance of axonal pathology to degeneration can only be addressed through longitudinal, in vivo monitoring of different neuronal compartments. With current imaging methods, dopaminergic neurons do not readily lend themselves to such a task in any vertebrate system. We therefore expressed human wild-type aSyn in zebrafish peripheral sensory neurons, which project elaborate superficial axons that can be continuously imaged in vivo. Axonal outgrowth was normal in these neurons but, by 2 days post-fertilization (dpf, many aSyn-expressing axons became dystrophic, with focal varicosities or diffuse beading. Approximately 20% of aSyn-expressing cells died by 3 dpf. Time-lapse imaging revealed that focal axonal swelling, but not overt fragmentation, usually preceded cell death. Co-expressing aSyn with a mitochondrial reporter revealed deficits in mitochondrial transport and morphology even when axons appeared overtly normal. The axon-protective protein Wallerian degeneration slow (WldS delayed axon degeneration but not cell death caused by aSyn. By contrast, the transcriptional coactivator PGC-1α, which has roles in the regulation of mitochondrial biogenesis and reactive-oxygen-species detoxification, abrogated aSyn toxicity in both the axon and the cell body. The rapid onset of axonal pathology in this system, and the relatively moderate degree of cell death, provide a new model for the study of aSyn toxicity and protection. Moreover, the accessibility of peripheral sensory axons will allow effects of aSyn to be studied in different neuronal compartments and might have utility in

  1. Axonal transport and incorporation of radioactivity after injection of N-[3H]acetyl-D-mannosamine into rat mesencephalon

    International Nuclear Information System (INIS)

    A study has been performed to demonstrate the possibility of incorporation of sialic acid into nerve endings of the rubrospinal tract after antegrade axonal transport. Young adult rats received injections of N-[3H]acetyl-D-mannosamine into the red nucleus and axonal transport of the tritiated compounds along the axons of afferent and efferent connections of the red nucleus was studied and the transported material was analysed. Light microscopic autoradiography and biochemical methods were used. (Auth./C.F.)

  2. A Purine-Sensitive Pathway Regulates Multiple Genes Involved in Axon Regeneration in Goldfish Retinal Ganglion Cells

    OpenAIRE

    Petrausch, Barbara; Tabibiazar, Raymond; Roser, Timo; Jing, Yun; Goldmann, Daniel; Stürmer, Claudia; Irwin, Nina; Benowitz, Larry I.

    2000-01-01

    In lower vertebrates, retinal ganglion cells (RGCs) can regenerate their axons and reestablish functional connections after optic nerve injury. We show here that in goldfish RGCs, the effects of several trophic factors converge on a purine-sensitive signaling mechanism that controls axonal outgrowth and the expression of multiple growth-associated proteins. In culture, goldfish RGCs regenerate their axons in response to two molecules secreted by optic nerve glia, axogenesis factor-1 (AF-1) an...

  3. The contributions of myelin and axonal caliber to transverse relaxation time in shiverer and neurofilament-deficient mouse models

    OpenAIRE

    Dyakin, Victor V.; Chen, Yuanxin; Branch, Craig A.; Veeranna; Yuan, Aidong; Rao, Mala; Kumar, Asok; Peterhoff, Corrinne M.; Nixon, Ralph A

    2010-01-01

    White matter disorders can involve injury to myelin or axons but the respective contribution of each to clinical course is difficult to evaluate non-invasively. Here, to develop a paradigm for further investigations of axonal pathology by MRI, we compared two genetic mouse models exhibiting relatively selective axonal or myelin deficits using quantitative MRI relaxography of the transverse relaxation times (T2) in vivo and ultrastructural morphometry. In HM-DKO mice, which lack genes encoding...

  4. L-carnitine enhances axonal plasticity and improves white-matter lesions after chronic hypoperfusion in rat brain

    OpenAIRE

    Ueno, Yuji; Koike, Masato; Shimada, Yoshiaki; Shimura, Hideki; Hira, Kenichiro; Tanaka, Ryota; Uchiyama, Yasuo; Hattori, Nobutaka; Urabe, Takao

    2014-01-01

    Chronic cerebral hypoperfusion causes white-matter lesions (WMLs) with oxidative stress and cognitive impairment. However, the biologic mechanisms that regulate axonal plasticity under chronic cerebral hypoperfusion have not been fully investigated. Here, we investigated whether L-carnitine, an antioxidant agent, enhances axonal plasticity and oligodendrocyte expression, and explored the signaling pathways that mediate axonal plasticity in a rat chronic hypoperfusion model. Adult male Wistar ...

  5. Ion channel clustering at the axon initial segment and node of Ranvier evolved sequentially in early chordates.

    OpenAIRE

    Hill, Alexis S.; Atsuo Nishino; Koichi Nakajo; Giuxin Zhang; Fineman, Jaime R.; Selzer, Michael E.; Yasushi Okamura; Cooper, Edward C.

    2008-01-01

    In many mammalian neurons, dense clusters of ion channels at the axonal initial segment and nodes of Ranvier underlie action potential generation and rapid conduction. Axonal clustering of mammalian voltage-gated sodium and KCNQ (Kv7) potassium channels is based on linkage to the actin–spectrin cytoskeleton, which is mediated by the adaptor protein ankyrin-G. We identified key steps in the evolution of this axonal channel clustering. The anchor motif for sodium channel clustering evolved earl...

  6. Brain-derived neurotrophic factor gene transfection promotes neuronal repair and neurite regeneration after diffuse axonal injury

    Institute of Scientific and Technical Information of China (English)

    Yin Yu; Chao Du; Xingli Zhao; Jiajia Shao; Qiang Shen; Tao Jiang; Wei Wu; Dong Zhu; Yu Tian; Yongchuan Guo

    2011-01-01

    This study sought to assess the potential of brain-derived neurotrophic factor (BDNF) to promote neuronal repair and regeneration in rats with diffuse axonal injury, and to examine the accompanying neurobiological changes. BDNF gene transfection reduced the severity of the pathological changes associated with diffuse axonal injury in cortical neurons of the frontal lobe and increased neurofilament protein expression. These findings demonstrate that BDNF can effectively promote neuronal repair and neurite regeneration after diffuse axonal injury.

  7. The comparison of the value of ct imaging and selected MRI sequences (including DWI) in the evaluation of axonal injuries

    OpenAIRE

    Paszkowska, Emilia; Wasilewski, Grzegorz; Szalcunas-Olsztyn, Anna; Jancewicz, Patryk; Stefanowicz, Elżbieta

    2010-01-01

    Summary Background: Diffuse axonal injuries of the brain consist in the damage (overstretching or torsion) of white matter axons, as a result of the forces of energy waves, evoked in the moment of injury, together with its accelerating-retarding inertia effect. Patients with DAI are most frequently the casualties of high speed car accidents. Diffuse axonal injuries of the brain are one of the most common acute brain injuries, with lesions typically occurring in the periventricular white matte...

  8. Time-Lapse Imaging of the Dynamics of CNS Glial-Axonal Interactions In Vitro and Ex Vivo

    OpenAIRE

    Kalliopi Ioannidou; Anderson, Kurt I; David Strachan; Edgar, Julia M.; Barnett, Susan C.

    2012-01-01

    Background Myelination is an exquisite and dynamic example of heterologous cell-cell interaction, which consists of the concentric wrapping of multiple layers of oligodendrocyte membrane around neuronal axons. Understanding the mechanism by which oligodendrocytes ensheath axons may bring us closer to designing strategies to promote remyelination in demyelinating diseases. The main aim of this study was to follow glial-axonal interactions over time both in vitro and ex vivo to visualize th...

  9. Bergmann glia and the recognition molecule CHL1 organize GABAergic axons and direct innervation of Purkinje cell dendrites.

    Directory of Open Access Journals (Sweden)

    Fabrice Ango

    2008-04-01

    Full Text Available The geometric and subcellular organization of axon arbors distributes and regulates electrical signaling in neurons and networks, but the underlying mechanisms have remained elusive. In rodent cerebellar cortex, stellate interneurons elaborate characteristic axon arbors that selectively innervate Purkinje cell dendrites and likely regulate dendritic integration. We used GFP BAC transgenic reporter mice to examine the cellular processes and molecular mechanisms underlying the development of stellate cell axons and their innervation pattern. We show that stellate axons are organized and guided towards Purkinje cell dendrites by an intermediate scaffold of Bergmann glial (BG fibers. The L1 family immunoglobulin protein Close Homologue of L1 (CHL1 is localized to apical BG fibers and stellate cells during the development of stellate axon arbors. In the absence of CHL1, stellate axons deviate from BG fibers and show aberrant branching and orientation. Furthermore, synapse formation between aberrant stellate axons and Purkinje dendrites is reduced and cannot be maintained, leading to progressive atrophy of axon terminals. These results establish BG fibers as a guiding scaffold and CHL1 a molecular signal in the organization of stellate axon arbors and in directing their dendritic innervation.

  10. 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

    OpenAIRE

    Cerliani, Juan P.; Sebastián Giulianelli; Ana Sahores; Victoria Wargon; Adrián Gongora; Alberto Baldi; Alfredo Molinolo; Lamb, Caroline A.; Claudia Lanari

    2010-01-01

    We have previously demonstrated a crosstalk between fibroblast growth factor 2 (FGF2) and progestins inducing experimental breast cancer growth. The aim of the present study was to compare the effects of FGF2 and of medroxyprogesterone acetate (MPA) on the mouse mammary glands and to investigate whether the antiprogestin RU486 was able to reverse the MPA- or FGF2-induced effects on both, mammary gland and tumor growth. We demonstrate that FGF2 administered locally induced an intraductal hyper...

  11. The impact of motor axon misdirection and attrition on behavioral deficit following experimental nerve injuries.

    Directory of Open Access Journals (Sweden)

    Jacob Daniel de Villiers Alant

    Full Text Available Peripheral nerve transection and neuroma-in-continuity injuries are associated with permanent functional deficits, often despite successful end-organ reinnervation. Axonal misdirection with non-specific reinnervation, frustrated regeneration and axonal attrition are believed to be among the anatomical substrates that underlie the poor functional recovery associated with these devastating injuries. Yet, functional deficits associated with axonal misdirection in experimental neuroma-in-continuity injuries have not yet been studied. We hypothesized that experimental neuroma-in-continuity injuries would result in motor axon misdirection and attrition with proportional persistent functional deficits. The femoral nerve misdirection model was exploited to assess major motor pathway misdirection and axonal attrition over a spectrum of experimental nerve injuries, with neuroma-in-continuity injuries simulated by the combination of compression and traction forces in 42 male rats. Sciatic nerve injuries were employed in an additional 42 rats, to evaluate the contribution of axonal misdirection to locomotor deficits by a ladder rung task up to 12 weeks. Retrograde motor neuron labeling techniques were utilized to determine the degree of axonal misdirection and attrition. Characteristic histological neuroma-in-continuity features were demonstrated in the neuroma-in-continuity groups and poor functional recovery was seen despite successful nerve regeneration and muscle reinnervation. Good positive and negative correlations were observed respectively between axonal misdirection (p<.0001, r(2=.67, motor neuron counts (attrition (p<.0001, r(2=.69 and final functional deficits. We demonstrate prominent motor axon misdirection and attrition in neuroma-in-continuity and transection injuries of mixed motor nerves that contribute to the long-term functional deficits. Although widely accepted in theory, to our knowledge, this is the first experimental evidence to

  12. Synergistic integration of Netrin and ephrin axon guidance signals by spinal motor neurons.

    Science.gov (United States)

    Poliak, Sebastian; Morales, Daniel; Croteau, Louis-Philippe; Krawchuk, Dayana; Palmesino, Elena; Morton, Susan; Cloutier, Jean-François; Charron, Frederic; Dalva, Matthew B; Ackerman, Susan L; Kao, Tzu-Jen; Kania, Artur

    2015-01-01

    During neural circuit assembly, axonal growth cones are exposed to multiple guidance signals at trajectory choice points. While axonal responses to individual guidance cues have been extensively studied, less is known about responses to combination of signals and underlying molecular mechanisms. Here, we studied the convergence of signals directing trajectory selection of spinal motor axons entering the limb. We first demonstrate that Netrin-1 attracts and repels distinct motor axon populations, according to their expression of Netrin receptors. Quantitative in vitro assays demonstrate that motor axons synergistically integrate both attractive or repulsive Netrin-1 signals together with repulsive ephrin signals. Our investigations of the mechanism of ephrin-B2 and Netrin-1 integration demonstrate that the Netrin receptor Unc5c and the ephrin receptor EphB2 can form a complex in a ligand-dependent manner and that Netrin-ephrin synergistic growth cones responses involve the potentiation of Src family kinase signaling, a common effector of both pathways. PMID:26633881

  13. X11/Mint genes control polarized localization of axonal membrane proteins in vivo.

    Science.gov (United States)

    Gross, Garrett G; Lone, G Mohiddin; Leung, Lok Kwan; Hartenstein, Volker; Guo, Ming

    2013-05-01

    Mislocalization of axonal proteins can result in misassembly and/or miswiring of neural circuits, causing disease. To date, only a handful of genes that control polarized localization of axonal membrane proteins have been identified. Here we report that Drosophila X11/Mint proteins are required for targeting several proteins, including human amyloid precursor protein (APP) and Drosophila APP-like protein (APPL), to axonal membranes and for their exclusion from dendrites of the mushroom body in Drosophila, a brain structure involved in learning and memory. Axonal localization of APP is mediated by an endocytic motif, and loss of X11/Mint results in a dramatic increase in cell-surface levels of APPL, especially on dendrites. Mutations in genes required for endocytosis show similar mislocalization of these proteins to dendrites, and strongly enhance defects seen in X11/Mint mutants. These results suggest that X11/Mint-dependent endocytosis in dendrites may serve to promote the axonal localization of membrane proteins. Since X11/Mint binds to APP, and abnormal trafficking of APP contributes to Alzheimer's disease, deregulation of X11/Mint may be important for Alzheimer's disease pathogenesis. PMID:23658195

  14. Synapse formation between isolated axons requires presynaptic soma and redistribution of postsynaptic AChRs.

    Science.gov (United States)

    Meems, Ryanne; Munno, David; van Minnen, Jan; Syed, Naweed I

    2003-05-01

    The involvement of neuronal protein synthetic machinery and extrinsic trophic factors during synapse formation is poorly understood. Here we determine the roles of these processes by reconstructing synapses between the axons severed from identified Lymnaea neurons in cell culture, either in the presence or absence of trophic factors. We demonstrate that, although synapses are maintained between isolated pre- and postsynaptic axons for several days, the presynaptic, but not the postsynaptic, cell body, however, is required for new synapse formation between soma-axon pairs. The formation of cholinergic synapses between presynaptic soma and postsynaptic axon requires gene transcription and protein synthesis solely in the presynaptic neuron. We show that this synaptogenesis is contingent on extrinsic trophic factors present in brain conditioned medium (CM). The CM-induced excitatory synapse formation is mediated through receptor tyrosine kinases. We further demonstrate that, although the postsynaptic axon does not require new protein synthesis for synapse formation, its contact with the presynaptic cell in CM, but not in defined medium (no trophic factors), differentially alters its responsiveness to exogenously applied acetylcholine at synaptic compared with extrasynaptic sites. Together, these data suggest a synergetic action of cell-cell signaling and trophic factors to bring about specific changes in both pre- and postsynaptic neurons during synapse formation.

  15. A large fraction of neocortical myelin ensheathes axons of local inhibitory neurons

    Science.gov (United States)

    Micheva, Kristina D; Wolman, Dylan; Mensh, Brett D; Pax, Elizabeth; Buchanan, JoAnn; Smith, Stephen J; Bock, Davi D

    2016-01-01

    Myelin is best known for its role in increasing the conduction velocity and metabolic efficiency of long-range excitatory axons. Accordingly, the myelin observed in neocortical gray matter is thought to mostly ensheath excitatory axons connecting to subcortical regions and distant cortical areas. Using independent analyses of light and electron microscopy data from mouse neocortex, we show that a surprisingly large fraction of cortical myelin (half the myelin in layer 2/3 and a quarter in layer 4) ensheathes axons of inhibitory neurons, specifically of parvalbumin-positive basket cells. This myelin differs significantly from that of excitatory axons in distribution and protein composition. Myelin on inhibitory axons is unlikely to meaningfully hasten the arrival of spikes at their pre-synaptic terminals, due to the patchy distribution and short path-lengths observed. Our results thus highlight the need for exploring alternative roles for myelin in neocortical circuits. DOI: http://dx.doi.org/10.7554/eLife.15784.001 PMID:27383052

  16. Imaging axonal degeneration and repair in pre-clinical animal models of multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Soumya S Yandamuri

    2016-05-01

    Full Text Available Multiple sclerosis (MS is a central nervous system (CNS disease characterized by chronic neuroinflammation, demyelination, and axonal damage. Infiltration of activated lymphocytes and myeloid cells are thought to be primarily responsible for white matter damage and axonopathy. Over time, this neurologic damage manifests clinically as debilitating motor and cognitive symptoms. Existing MS therapies focus on symptom relief and delay of disease progression through reduction of neuroinflammation. However, long-term strategies to remyelinate, protect, or regenerate axons have remained elusive, posing a challenge to treating progressive forms of MS. Preclinical mouse models and techniques such as immunohistochemistry, flow cytometry, and genomic and proteomic analysis have provided advances in our understanding of discrete time-points of pathology following disease induction. More recently, in vivo and in situ two-photon microscopy (2P has made it possible to visualize continuous real-time cellular behavior and structural changes occurring within the CNS during neuropathology. Research utilizing 2P imaging to study axonopathy in neuroinflammatory demyelinating disease has focused on five areas: (1 axonal morphologic changes (2 organelle transport and health, (3 relationship to inflammation, (4 neuronal excitotoxicity, and (5 regenerative therapies. 2P imaging may also be used to identify novel therapeutic targets via identification and clarification of dynamic cellular and molecular mechanisms of axonal regeneration and remyelination. Here, we review tools that have made 2P accessible for imaging neuropathologies and advances in our understanding of axonal degeneration and repair in preclinical models of demyelinating diseases.

  17. PACAP enhances axon outgrowth in cultured hippocampal neurons to a comparable extent as BDNF.

    Directory of Open Access Journals (Sweden)

    Katsuya Ogata

    Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP exerts neurotrophic activities including modulation of synaptic plasticity and memory, hippocampal neurogenesis, and neuroprotection, most of which are shared with brain-derived neurotrophic factor (BDNF. Therefore, the aim of this study was to compare morphological effects of PACAP and BDNF on primary cultured hippocampal neurons. At days in vitro (DIV 3, PACAP increased neurite length and number to similar levels by BDNF, but vasoactive intestinal polypeptide showed much lower effects. In addition, PACAP increased axon, but not dendrite, length, and soma size at DIV 3 similarly to BDNF. The PACAP antagonist PACAP6-38 completely blocked the PACAP-induced increase in axon, but not dendrite, length. Interestingly, the BDNF-induced increase in axon length was also inhibited by PACAP6-38, suggesting a mechanism involving PACAP signaling. K252a, a TrkB receptor inhibitor, inhibited axon outgrowth induced by PACAP and BDNF without affecting dendrite length. These results indicate that in primary cultured hippocampal neurons, PACAP shows morphological actions via its cognate receptor PAC1, stimulating neurite length and number, and soma size to a comparable extent as BDNF, and that the increase in total neurite length is ascribed to axon outgrowth.

  18. Formation of compact myelin is required for maturation of the axonal cytoskeleton

    Science.gov (United States)

    Brady, S. T.; Witt, A. S.; Kirkpatrick, L. L.; de Waegh, S. M.; Readhead, C.; Tu, P. H.; Lee, V. M.

    1999-01-01

    Although traditional roles ascribed to myelinating glial cells are structural and supportive, the importance of compact myelin for proper functioning of the nervous system can be inferred from mutations in myelin proteins and neuropathologies associated with loss of myelin. Myelinating Schwann cells are known to affect local properties of peripheral axons (de Waegh et al., 1992), but little is known about effects of oligodendrocytes on CNS axons. The shiverer mutant mouse has a deletion in the myelin basic protein gene that eliminates compact myelin in the CNS. In shiverer mice, both local axonal features like phosphorylation of cytoskeletal proteins and neuronal perikaryon functions like cytoskeletal gene expression are altered. This leads to changes in the organization and composition of the axonal cytoskeleton in shiverer unmyelinated axons relative to age-matched wild-type myelinated fibers, although connectivity and patterns of neuronal activity are comparable. Remarkably, transgenic shiverer mice with thin myelin sheaths display an intermediate phenotype indicating that CNS neurons are sensitive to myelin sheath thickness. These results indicate that formation of a normal compact myelin sheath is required for normal maturation of the neuronal cytoskeleton in large CNS neurons.

  19. Altered potassium channel distribution and composition in myelinated axons suppresses hyperexcitability following injury.

    Science.gov (United States)

    Calvo, Margarita; Richards, Natalie; Schmid, Annina B; Barroso, Alejandro; Zhu, Lan; Ivulic, Dinka; Zhu, Ning; Anwandter, Philipp; Bhat, Manzoor A; Court, Felipe A; McMahon, Stephen B; Bennett, David L H

    2016-01-01

    Neuropathic pain following peripheral nerve injury is associated with hyperexcitability in damaged myelinated sensory axons, which begins to normalise over time. We investigated the composition and distribution of shaker-type-potassium channels (Kv1 channels) within the nodal complex of myelinated axons following injury. At the neuroma that forms after damage, expression of Kv1.1 and 1.2 (normally localised to the juxtaparanode) was markedly decreased. In contrast Kv1.4 and 1.6, which were hardly detectable in the naïve state, showed increased expression within juxtaparanodes and paranodes following injury, both in rats and humans. Within the dorsal root (a site remote from injury) we noted a redistribution of Kv1-channels towards the paranode. Blockade of Kv1 channels with α-DTX after injury reinstated hyperexcitability of A-fibre axons and enhanced mechanosensitivity. Changes in the molecular composition and distribution of axonal Kv1 channels, therefore represents a protective mechanism to suppress the hyperexcitability of myelinated sensory axons that follows nerve injury. PMID:27033551

  20. Nicotinamide mononucleotide adenylyltransferase 1 gene NMNAT1 regulates neuronal dendrite and axon morphogenesis in vitro

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hong; ZHANG Jing-yu; YANGZi-chao; LIU Ming; GANG Bao-zhi; ZHAO Qing-jie

    2011-01-01

    Background Wallerian degeneration is a self-destructive process of axonal degeneration that occurs after an axonal injury or during neurodegenerative disorders such as Parkinson's or Alzheimer's disease.Recent studies have found that the activity of the nicotinamide adenine dinucleotide (NAD) synthase enzyme,nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) can affect the rate of Wallerian degeneration in mice and drosophila.NMNAT1 protects neurons and axons from degeneration.However,the role of NMNAT1 in neurons of central nervous system is still not well understood.Methods We set up the culture of primary mouse neurons in vitro and manipulated the expression level of NMNAT1 by RNA interference and gene overexpression methods.Using electroporation transfection we can up-regulate or down-regulate NMNAT1 in cultured mouse dendrites and axons and study the neuronal morphogenesis by immunocytochemistry.In all functional assays,FK-866 (CAS 658084-64-1),a highly specific non-competitive inhibitor of nicotinamide phosphoribosyltransferase was used as a pharmacological and positive control.Results Our results showed that knocking down NMNAT1 by RNA interference led to a marked decrease in dendrite outgrowth and branching and a significant decrease in axon growth and branching in developing cortical neurons in vitro.Conclusions These findings reveal a novel role for NMNAT1 in the morphogenesis of developing cortical neurons,which indicate that the loss of function of NMNAT1 may contribute to different neurodegenerative disorders in central nervous system.