Estudio comparativo del efecto antiinflamatorio del plantago major "Llantén" y del diclofenaco / Comparative study of the antiinflammatory effect of the plantago major

Se determinó la Dosis Letal 50(DL50) del extracto metanólico del Plantago major "Llantén" administrado por vía intraperitoneal, hallándose como resultado una DL50 equivalente a 4,000 mg/Kg de peso de animal utilizándose para ello 36 ratones divididos en 6 grupos de 6 animales cada uno. Se utilizarón 40 ratas albinas divididas en 4 grupos de 10 animales cada uno, a las cuales se les infiltró en el lomo 2 ml de carragenina al 1 por ciento a las bolsas de aire. Después de 30' de haber colocado la carragenina se administró los extractos y el diclofenaco. A las seis horas fueron sacrificados los animales. Del exudado obtenido se utilizó una parte para el recuento de Leucocitos en el Coulter Counter, el resto se centrifugó para determinar la concentración de proteínas totales por el método colorimétrico de Gornall utilizando el reactivo de Biuret y un patrón de proteína de 70 g/L. Se evidenció las propiedades antiinflamatorias significativas del extracto metanólico, administrado por vía intraperitoneal, a la dosis de 400 mg/Kg y 800 mg/Kg de peso frente al diclofenaco, utilizando la técnica estandarizada de Edwars (CYTED), del Granuloma de Pouche.

We have determined the 50 Lethal dose of the Metanolic extract of Plantago major "Llanten" given by intraperitoneal route. We have found that 50LD was 4000 mg/Kg. Of animal weigtht, using 36 mice divided in six groups with 6 animal s each one. 40 rats divided in four groups of ten animals each one received on the back 2 mI of carragenin 1 % to the air pouch. After 30 minutes, the extract and diclofenac were administered. Six hours afterwards the animal s were killed. The exudate obtained was used to find the leucocyte count in the Coulter Counter. The rest of the material was centrifuged to determine the concentracion of proteins with de Gornall colorimetric method using the Biuret reactive and a model of protein lof 70 g/L. We found the anti-inflammatory properties of the methanolic extract, administered by the intraperitoneal route 400 mg/Kg. and 800mg/Kg and with diclofenac using the standardized technique of Edwards (CYTED) from the granuloma of .. Pouche.

Glucoprivation increases estrogen receptor alpha immunoreactivity in the brain catecholaminergic neurons in ovariectomized rats.

Estrogen-dependent enhancement of glucoprivic-induced luteinizing hormone (LH) suppression is hypothesized to be due to increased estrogen receptor alpha (ERalpha)-immunoreactive (ir) cells in specific brain nuclei in a manner similar to fasting. ERalpha expression in various brain areas was determined in ovariectomized rats after systemic 2-deoxy-D-glucose (2DG)-induced glucoprivation. Expression of ERalpha in catecholaminergic neurons in the lower brainstem was also examined. ERalpha-ir cells increased in hypothalamic paraventricular and periventricular nuclei, and A1 and A2 regions of the brainstem 1 h after 2DG injection. The percentage of ERalpha in the tyrosine hydroxylase (TH)- and dopamine-beta-hydroxylase (DBH)-ir neurons was higher in A1 and A2 regions of 2DG-treated rats, but the number of TH- and DBH-ir cells did not change. Thus, 2DG induces ERalpha expression in specific brain nuclei and expression of ERalpha in catecholaminergic neurons of the brainstem indicates a role for estrogen in activating those neurons projecting to the hypothalamic paraventricular nucleus to suppress LH secretion during glucoprivation.

Reintervenciones en cirugía laparoscópica / Reintervention in laparoscopic surgery

Objetivo. Valorar la influencia que puede tener la cirugía abdominal y laparoscópica previa en las reintervenciones por vía laparoscópica, analizando los resultados y las causas de dichas reintervenciones. Pacientes y métodos. Estudio retrospectivo de 4.957 pacientes intervenidos por vía laparoscópica entre octubre de 1991 y octubre de 1999, correspondiendo el mayor número de intervenciones a la cirugía biliar (2.028). En 769 pacientes (15,5 por ciento) existía el antecedente de cirugía abdominal previa, en 43 de los cuales (0,9 por ciento) ésta se había efectuado por laparoscopia. Resultados. El número total de conversiones en todos los pacientes intervenidos fue de 74 (1,49 por ciento). La causa más frecuente de conversión fueron las dificultades técnicas (63,5 por ciento), cifra más elevada que cuando la causa de conversión fue el antecedente de cirugía convencional (27 por ciento). La morbilidad fue superior en los pacientes que presentaban cirugía abdominal previa (3,2 por ciento), frente al 1,3 por ciento en los pacientes que no habían sido intervenidos previamente. La causa de reintervención de la cirugía laparoscópica más frecuente fue el fallo de la cirugía por enfermedad por reflujo gastroesofágico (16,2 por ciento). El tiempo quirúrgico, las complicaciones intraoperatorias y el tiempo de estancia hospitalaria no presenta ninguna diferencia significativa en pacientes con o sin intervención previa, tanto en el grupo de laparotomía como de laparoscopia. Conclusiones. El análisis de los resultados demuestra que las reintervenciones por vía laparoscópica son factibles, independientemente de si existe o no cirugía previa. El número de reintervenciones como consecuencia de la cirugía laparoscópica previa puede reducirse respetando los principios quirúrgicos, admitidos en todo tipo de cirugía (AU)

Novel estrogen feedback sites associated with stress-induced suppression of luteinizing hormone secretion in female rats.

1. The fasting-induced suppression of LH secretion is totally dependent on steroidal milieu because the suppression is observed only in intact or ovariectomized estrogen-primed rats but not in ovariectomized animals. The following neural pathway mediating fasting-induced suppression of LH secretion has been suggested by a series of experiment: A neural signal emanating from the stomach during fasting reaches the medulla oblongata via afferent vagal nerve so as to activate the noradrenergic system projecting to the PVN: this results in an increased CRH release, and in turn the suppression of the LHRH release and then LH release. Estrogen seems to activate the neural pathway by acting on somewhere in the pathway. 2. We found that the paraventricular nucleus of the hypothalamus (PVN) and A2 region of the medulla oblongata is the estrogen feedback sites associated the dependence of the fasting-induced suppression of LH secretion on estrogen. The estrogen feedback action on the PVN does not involve an increase in norepinephrine release in the PVN. In addition, we also found that estrogen receptors are increased in the PVN and A2 region by acute fasting. Therefore, the following hypothesis is proposed: fasting first induces an transient increase in the activity of noradrenergic system at the beginning of the first dark phase after the food deprivation; this activation results in an increase in estrogen receptors in the PVN and A2 region; the increase in estrogen receptors leads to an increase in the sensitivity of noradrenergic systems to the neural inputs associated with fasting to these nuclei. 3. The response of the reproductive activity to various external stimuli including stress is modulated by ovarian steroids. The estrogen feedback action on the PVN and A2 is totally different from the so-called "negative feedback action" of estrogen that is for monitoring the ovarian condition. The novel estrogen feedback action may alter the response of neurons regulating gonadal axis to the signal associated with environmental cues such as stress.

Reduction of glucose availability suppresses pulsatile luteinizing hormone release in female and male rats.

Glucose availability controls reproductive activity through modulation of LH secretion. The aim of the present study was to determine whether the glucoprivic suppression is potentiated by gonadal steroids and if glucoprivic suppression of pulsatile LH release is sexually differentiated. Pulsatile LH secretion was examined in rats after peripheral (jugular) administration of the competitive inhibitor of glycolysis, 2-deoxyglucose (2DG). Fourteen days after gonadectomy, blood samples were collected every 6 min for 3 h. One hour after the onset of sampling, 2DG was administered peripherally (200, 400, or 800 mg/kg BW, iv), and food intake was determined after 2DG injection in gonadectomized males and females in the presence or absence of sex steroids (testosterone or estradiol). To test the ability of the pituitary to produce LH under glucoprivic conditions, LHRH was injected every 30 min for 2.5 h in ovariectomized (OVX) rats 30 min after treatment with 400 mg/kg 2DG. At all peripheral doses of 2DG in females and at the middle and high doses of 2DG in males, mean plasma LH and LH pulse frequency decreased (P < 0.05) in the presence of steroids. However, in the absence of sex steroids, the lowest dose in females and the middle dose in males were not effective. Pituitary function appeared normal, because increases in mean plasma LH in response to the exogenous LHRH occurred in OVX rats treated with the middle dose of 2DG. Food intake significantly (P < 0.05) increased after 2DG injection in all groups except estrogen-treated OVX females at the low and high doses of 2DG. These findings suggest that glucoprivic suppression of LH pulses is potentiated by gonadal steroids in both sexes. Moreover, the hypothalamo-hypophyseal axis of the female rat seems to be more sensitive to the decreased glucose availability induced by 2DG than that of the male.

Vagus nerve mediates the increase in estrogen receptors in the hypothalamic paraventricular nucleus and nucleus of the solitary tract during fasting in ovariectomized rats.

The effect of total subdiaphragmatic vagotomy on estrogen-receptor immunoreactivity (ERIR) in the paraventricular nucleus (PVN) and nucleus of the solitary tract (NTS) was examined in fasted ovariectomized rats to clarify the peripheral inputs mediating fasting-induced increase in ERIR in these two nuclei. Vagotomy abolished the effect of 48-h fasting on the expression of ER in these two areas. The result indicates that the neural signal(s) that increase the expression of ER in the PVN and A2 region of the NTS following 48-h fasting is transmitted through the vagus. The involvement of the vagus in the fasting-induced increase in ER in the PVN and A2 region may also be the same neural pathway involved in the suppression of pulsatile luteinizing hormone secretion in fasted female rats.

Effect of fasting and immobilization stress on estrogen receptor immunoreactivity in the brain in ovariectomized female rats.

The present study examined the effect of 48-h fasting and 1-h immobilization on estrogen receptor immunoreactivity in selected hypothalamic areas and the nucleus of the solitary tract (NTS) in ovariectomized rats. Fasting induced an increase in ER-immunoreactive cells in the paraventricular nucleus (PVN), periventricular nucleus (PeVN) and NTS compared with the unfasted control group. Similarly, immobilization caused an increase in ER-positive cells in the same areas, PVN, PeVN and NTS, versus the non-immobilized group. There was no significant increase in the number of ER-immunoreactive cells in the preoptic area (POA), arcuate nucleus (ARC) or ventromedial hypothalamic nucleus (VMH) following fasting and immobilization. Our previous work in ovariectomized rats with estrogen microimplants in the brain revealed that the PVN and A2 region of the NTS are the feedback sites of estrogen in activating the neural pathway to suppress pulsatile LH secretion during 48-h fasting. The result in the food-deprived rats suggests that estrogen modulation of the suppression of LH secretion during fasting is partly due to the increase in estrogen receptors in the PVN and A2 region. The physiological significance of the increase in neural ER following immobilization remains to be elucidated.