Circadian variation in the neoplasic hepatocytes proliferation from the ES 15 tumor

Como numerosos procesos biológicos, la proliferación de diversas poblaciones celulares animales presenta un ritmo circadiano. La respuesta diferencial a la ciclofosfamida ha sido relacionada con la periodicidad mitótica diaria en un carcinoma mamario de ratón. El presente trabajo analiza la evolución de la actividad mitótica, a lo largo de un ciclo de 24 h, de los hepatocitos neoplásicos del tumor E515 (hepatocarcinoma diferenciado, de crecimiento lento), 38 ratones machos, adultos de la cepa C3H/5, fueron injertados con el tumor en el tejido celular subcutáneo. Al cabo de 10 semanas los portadores fueron colocados durante tres semanas en condiciones de estandarización para análisis de periodicidad. Pasado ese lapso los mismos se repartieron en 6 lotes (n=5-8) que se sacrificaron cada 4 horas a partir de la hora 00:00 hasta abarcar un período de 24 h, tras recibir una dosis de Colchicina (2 µg/g/0,O1 ml). Las muestras del tumor se procesaron para observación microscópica bajo objetivo de inmersión. En los cortes se determinó por conteo mitótico el índice de metafases colchicínicas por 1.000 núcleos. Se observó que la actividad mitótica presenta su valor mínimo a las 04:00 horas y el máximo a las 16:00 h. Esta diferencia es estadísticamente significativa (P < 0,001). Este conocimiento es de utilidad para cualquier ensayo experimental que implique aspectos relacionados con la regulación del crecimiento del mismo tumor.As most of biological processes, the proliferation of a variety of mammalian cell populations shows a circadian rhythm. The differential response of a mouse mammary carcinoma to the endoxan (cyclophosphamide) administration, has been related to its daily mitotic periodicity. In this work we analyze the evolution of the mitotic activity, through a 24 h period, of the E515 tumor hepatocytes (Slow growing differentiated hepatocarcinoma). Thirty eight C3H/S inbred male adult mice, were grafted with the tumor in the hypodermis. Ten weeks later they were standardized for periodicity analysis during three weeks. After this time, they were separated in six groups (N=5-8) and one group every’ 4 h for a day was sacrificed. Four hours before killing, the mice received an IP injection of colchicine in a doses of 2 µg/g/0,O1 ml of distilled water. The colchicine metaphases were controlled on slides an the mitotic index per 1000 nuclei was determined. The lowest mitotic activity at 04:00 h and the highest at 16:O0 h were observed. The difference was highly significant (p < 0,001). The knowledge of this data is very useful for experimental assays related to any aspect of the same tumor growth regulation.Facultad de Ciencias Veterinaria

The pars distalis of the pituitary as a source of liver growth stimulating factors during liver regeneration

Plasma and pituitary extracts from hepatectomized mice as well as pure growth hormone, stimulate DNA synthesis in hepatocyte population of adult intact mouse liver. This effect is not observed with plasma and pituitary extracts from intact or sham operated mice. The corresponding effects on the litoral cell population of the liver follow the same pattern, but the results are not so clearcut as in the hepatocyte population. The possibility that growth hormone, released by STH cells of the pituitary, is one of the factors responsible for the stimulating effect of plasma during liver regeneration, is discussed on the basis of the present results and of those already reported in the literature.Facultad de Ciencias Médica

Ultrastructure of STH cells in the pars distalis of the hypophysis of mice bearing transplanted hepatomas

An electron microscopic analysis was performed on the pars distalis of the hypophysis of mice bearing transplanted hepatomas. Normal mice served as controls. In animals bearing a fast growing as well as in those bearing a slow growing hepatoma, the STH cells presented changes indicating increased release and synthesis of its secretory product. These changes can be summarized as follows: 1) Increased number of granuledepleted STH cells which were very irregular in size and shape. 2) Very irregular and sometimes bizarre nuclei. 3) Plasma membranes irregular and convoluted. 4) Increased quantity of endoplasmic reticulum which appeared sometimes dilated and contained material of varying electron density. 5) Abundant, irregular and frequently ramified mitochondria. 6) Hypertrophic Golgi system with increased number of microvesicles. 7) Increased number of large lysosomes of different type. 8) Increased number of fat droplets.Facultad de Ciencias Médica

Inhibiting effect of plasma from normal and tumour bearing mice on the mitotic rate of regenerating liver

Plasma from normal mice and from mice bearing the ES2 transplatable malignant tumour was injected intraperitoneally at a dose of 0.01 ml/g body weight in partially hepatectomized mice. Control animals were injected with a solution of sodium citrate in saline. The recipients were killed at the first (14:00 hours/48 h). These times are the time of day and the number of h after partial hepatectomy and second (14:00 hours/72 h) peak times after partial hepatectomy. The number of colchicine metaphases per 1000 nuclei was determined for hepatocytes and litoral cells. A different effect was obtained with plasma from tumour-bearing compared with normal mice. Plasma from both sources when injected 26 h after partial hepatectomy (16:00 hours/26 h) inhibited the mitotic activity of hepatocytes at the next peak of regenerative activity (14:00 hours/48 h). The plasma from tumour-bearing mice also inhibited the peak on the following day (14:00 hours/72 h), whereas plasma from normal mice had no inhibitory effect and, indeed, a compensatory wave was observed at this time. Furthermore, plasma from tumour-bearing mice also showed an inhibitory effect at the first peak (14:00 hours/48 h) when injected at the time of partial hepatectomy (14:00 hours/00 h) or at 22 h before partial hepatectomy (16:00 hours/ −22 h) whereas the injection of plasma from normal mice at these times had no inhibitory effect. In the litoral cells the injection of plasma from tumour-bearing mice made 22 h before hepatectomy (16:00 hours/ - 22 h) led to a stimulation of mitotic activity which was controlled at 14:00 hours/48 h. Injection made at the time of partial hepatectomy (14:00 hours/00 h) caused inhibition at 14:00 hours/48 h and injection at 26 h after partial hepatectomy (16:00 hours/26 h) had no effect. The three injections of normal plasma did not modify the mitotic activity of litoral cells at either 14:00 hours/48 h or at 14:00 hours/72 h.Facultad de Ciencias Médica

Circadian variation in the neoplasic hepatocytes proliferation from the ES 15 tumor

Como numerosos procesos biológicos, la proliferación de diversas poblaciones celulares animales presenta un ritmo circadiano. La respuesta diferencial a la ciclofosfamida ha sido relacionada con la periodicidad mitótica diaria en un carcinoma mamario de ratón. El presente trabajo analiza la evolución de la actividad mitótica, a lo largo de un ciclo de 24 h, de los hepatocitos neoplásicos del tumor E515 (hepatocarcinoma diferenciado, de crecimiento lento), 38 ratones machos, adultos de la cepa C3H/5, fueron injertados con el tumor en el tejido celular subcutáneo. Al cabo de 10 semanas los portadores fueron colocados durante tres semanas en condiciones de estandarización para análisis de periodicidad. Pasado ese lapso los mismos se repartieron en 6 lotes (n=5-8) que se sacrificaron cada 4 horas a partir de la hora 00:00 hasta abarcar un período de 24 h, tras recibir una dosis de Colchicina (2 µg/g/0,O1 ml). Las muestras del tumor se procesaron para observación microscópica bajo objetivo de inmersión. En los cortes se determinó por conteo mitótico el índice de metafases colchicínicas por 1.000 núcleos. Se observó que la actividad mitótica presenta su valor mínimo a las 04:00 horas y el máximo a las 16:00 h. Esta diferencia es estadísticamente significativa (P < 0,001). Este conocimiento es de utilidad para cualquier ensayo experimental que implique aspectos relacionados con la regulación del crecimiento del mismo tumor.As most of biological processes, the proliferation of a variety of mammalian cell populations shows a circadian rhythm. The differential response of a mouse mammary carcinoma to the endoxan (cyclophosphamide) administration, has been related to its daily mitotic periodicity. In this work we analyze the evolution of the mitotic activity, through a 24 h period, of the E515 tumor hepatocytes (Slow growing differentiated hepatocarcinoma). Thirty eight C3H/S inbred male adult mice, were grafted with the tumor in the hypodermis. Ten weeks later they were standardized for periodicity analysis during three weeks. After this time, they were separated in six groups (N=5-8) and one group every’ 4 h for a day was sacrificed. Four hours before killing, the mice received an IP injection of colchicine in a doses of 2 µg/g/0,O1 ml of distilled water. The colchicine metaphases were controlled on slides an the mitotic index per 1000 nuclei was determined. The lowest mitotic activity at 04:00 h and the highest at 16:O0 h were observed. The difference was highly significant (p < 0,001). The knowledge of this data is very useful for experimental assays related to any aspect of the same tumor growth regulation.Facultad de Ciencias Veterinaria

The pars distalis of the pituitary as a source of liver growth stimulating factors during liver regeneration

Plasma and pituitary extracts from hepatectomized mice as well as pure growth hormone, stimulate DNA synthesis in hepatocyte population of adult intact mouse liver. This effect is not observed with plasma and pituitary extracts from intact or sham operated mice. The corresponding effects on the litoral cell population of the liver follow the same pattern, but the results are not so clearcut as in the hepatocyte population. The possibility that growth hormone, released by STH cells of the pituitary, is one of the factors responsible for the stimulating effect of plasma during liver regeneration, is discussed on the basis of the present results and of those already reported in the literature.Facultad de Ciencias Médica

Study on a tumoral factors stimulant of hepatocyte mitosis

Numerosos tumores han demostrado producir factores con acción sobre el crecimiento tisular. En el presente trabajo se utiliza el extracto del tumor mamario EA34 que inyectado por vía intraperitoneal promueve el crecimiento hepatocítico del hígado del ratón joven con el propósito de extraer algunas conclusiones sobre la especificidad de su acción estimulante. Se utilizaron ratones endocriados, machos, estandarizados para análisis de periodicidad distribuidos en tres grupos: 1) jóvenes intactos, 2) adultos intactos, 3) adultos sub hepatectornizados. La mitad de cada grupo recibió una dosis de extracto de tumor EA34 y la mitad restante solución fisiológica, por vía intraperitoneal (IP). Todos los animales se sacrificaron después de recibir una dosis de colchicina. Se determino en los cortes el índice mitótico - metafases colchicínicas. Resultados: no se encontraron diferencias significativas entre los grupos comparados. Se concluye que la acción promotora observada, únicamente, sobre la población hepatocítica del ratón de 28 días de edad es compatible con la existencia: 1) en el extracto del tumor EA34, de un factor (o factores) estimulantes de la mitosis de los hepatocitos del animal joven; 2) de receptores en los hepatocitos del animal joven para el factor [o factores) estimulante detectado.The presence of a transplantable tumour may alter the mitotic activity of any of the normal host cell poputations. The effect of transplanted EA31 mammary carcinoma cells on the mitotic index of both the tongue keratinocytes and the liver hepatocytes and sinusoidal cells of adult female mice throughout a circadian cycle as compared with the corresponding values from normal animals is reported. Intact tumour bearing mice and non transplanted controls, standardized for periodicity analysis, were divided into groups. The tongues and livers were processed for the scoring of colchicines-arrested metaplasias. The keratinocytes and hepatocytes of both groups evidenced a circadian variation in mitotic index with the tumour-bearing mice showing a modification in the temporal distribution as well as a significant depression in the values. By contrast, the mitotic indices of the liver sinusoidal cells were both unaltered throughout the circadian cycle and unaffected by the presence of the transplanted tumour. The abnormal cellular proliferation in the tumour bearing animals could result from a substance elaborated by the neoplastic cells and/or from a factor produced by the normal host tissues. The possibility of mediation by some member of the TGFβ family is also considered.Facultad de Ciencias Veterinaria

Compresión de imágenes para diagnóstico médico utilizando redes neuronales

La compresión de imágenes es un tema ampliamente estudiado. Las soluciones convencionales ofrecen radios de compresión variables en función de la imagen de la cual se trate y en general, no ofrecen buenos resultados para imágenes con muchas variaciones en sus tonalidades El presente trabajo es una aplicación de compresión de imágenes de tomografías computadas de pacientes utilizando redes neuronales, que permite realizar tanto la compresión como la descompresión de las imágenes con un radio fijo de 8:1 y con una pérdida del 2%.Eje: Workshop sobre Aspectos Teoricos de la Inteligencia ArtificialRed de Universidades con Carreras en Informática (RedUNCI

Compresión de imágenes para diagnóstico médico utilizando redes neuronales

La compresión de imágenes es un tema ampliamente estudiado. Las soluciones convencionales ofrecen radios de compresión variables en función de la imagen de la cual se trate y en general, no ofrecen buenos resultados para imágenes con muchas variaciones en sus tonalidades El presente trabajo es una aplicación de compresión de imágenes de tomografías computadas de pacientes utilizando redes neuronales, que permite realizar tanto la compresión como la descompresión de las imágenes con un radio fijo de 8:1 y con una pérdida del 2%.Eje: Workshop sobre Aspectos Teoricos de la Inteligencia ArtificialRed de Universidades con Carreras en Informática (RedUNCI

Mitotic activity of the liver and tongue in mice bearing a transplanted mammary carcinoma

La portación de un tumor injertado puede acompañarse de modificaciones de la actividad mitótica (AM) de las poblaciones celulares normales del hospedante. En el presente trabajo se describe a lo largo de un período circadiano la evolución de la AM de la población de queratinocitos linguales y de la población de hepatocitos y de células sinusoidales del hígado de ratones adultos, hembras, injertados con el carcinoma mamario EA51 y se compara con los valores obtenidos de ratones normales. Muestras de hígado y lengua se procesaron para conteo microscópico bajo objetivo de inmersión. En los cortes se determinó el índice de metafases colchicinicas. A nivel de hepatocitos y de queratinocitos se observó, en ambos grupos, una VC de la AM; presentando los portadores tanto una modificación de la distribución temporal como una depresión significativa de la misma. En cambio a nivel de los sinusoides hepáticos no se registran diferencias, ni dentro ni entre los grupos considerados. Si bien la causa de la perturbación de la proliferación celular puede deberse a algún agente producido por las células tumorales y/o de los tejidos normales del animal se considera posible la participación de algún miembro de la familia del TGFβ.The presence of a transplantable tumour may alter the mitotic activity of any of the normal host cell poputations. The effect of transplanted EA31 mammary carcinoma cells on the mitotic index of both the tongue keratinocytes and the liver hepatocytes and sinusoidal cells of adult female mice throughout a circadian cycle as compared with the corresponding values from normal animals is reported. Intact tumour bearing mice and non transplanted controls, standardized for periodicity analysis, were divided into groups. The tongues and livers were processed for the scoring of colchicines-arrested metaplasias. The keratinocytes and hepatocytes of both groups evidenced a circadian variation in mitotic index with the tumour-bearing mice showing a modification in the temporal distribution as well as a significant depression in the values. By contrast, the mitotic indices of the liver sinusoidal cells were both unaltered throughout the circadian cycle and unaffected by the presence of the transplanted tumour. The abnormal cellular proliferation in the tumour bearing animals could result from a substance elaborated by the neoplastic cells and/or from a factor produced by the normal host tissues. The possibility of mediation by some member of the TGFβ family is also considered.Facultad de Ciencias Veterinaria