The effects of thymectomy performed on 10-day-old (Tx-10) mice on spontaneous puberty and the ovulatory response induced by gonadotrophin treatment were analysed, together with the effects of thymulin replacement from 10 days of age. Infantile thymectomy induced a delay of puberty, a decrease in serum 17 -oestradiol concentration and a reduced total number of follicles. Injection of thymulin (12 ng/g body weight) to Tx-10 mice resulted in an earlier onset of puberty, a decrease in the weights of ovaries and uterus, and an increase in serum 17 -oestradiol concentrations. In control and Tx-10 mice, treatment with pregnant mare serum gonadotrophin (PMSG) (5 IU) at 25 days of age resulted in ovulation and the numbers of ova shed by ovulating animals were similar. When the animals were injected with 1 IU PMSG ovulation did not occur. In Tx-10 mice, both 1 and 5 IU PMSG increased the number of follicles to values similar to those observed in the controls. In Tx-10 mice the sequential injection of PMSG (1 IU) and human chorionic gonadotrophin (hCG) (3 IU) resulted in ovulation, but the number of ova shed was lower than in controls. When these animals were injected daily with thymulin, an increase in the number of ova shed and serum 17 -oestradiol concentrations was observed. The uterine weight of Tx-10 mice was always significantly reduced in response to gonadotrophin treatment. Thymulin injection in PMSG-hCG-treated Tx-10 mice provoked a significant increase in uterine weight. The results suggest that the presence of the thymus after the neonatal period is necessary to normal ovarian development and function. The increase in gonadotrophin-induced ovarian response produced by thymulin replacement indicates that this peptide has a role in this process as one of the connecting signals between thymus and ovaries.
In prepubertal mice, subcutaneous thymulin injection before equine chorionic gonadotrophin (eCG) treatment simulates ovulation; seemingly, the thymulin could be acting at the hypothalamus-pituitary axis level. Objective: This study was designed to analyze the effects of injecting thymulin into the hypothalamus or pituitary on induced ovulation of prepubertal mice. Method: Female mice, 19 days old, were anesthetized with ether and injected with saline solution or thymulin into the anterior or medial hypothalamus or the pituitary and treated with eCG when 20 days old. The ova shed were counted and serum concentrations of 17β-estradiol were measured. In the ovaries, the morphometrical analysis was performed and the atresia evaluated. Results: Ether anesthesia treatment blocked eCG-induced ovulation in almost all animals. Mice anesthetized and treated with eCG and gonadotrophin-releasing hormone (GnRH) or human chorionic gonadotrophin (hCG) ovulated a full quota of ova. Injecting saline solution into the anterior or medial hypothalamus or the pituitary did not reduce the blocking effects of ether anesthesia on induced ovulation, but the incidence of atretic follicles was higher. Injecting thymulin directly into the anterior hypothalamus did not restore ovulation, nor diminish the number of atretic follicles. In contrast, injecting thymulin into the medial hypothalamus restored the ovulation ratio and decreased the percentage of atretic follicles. Similar results were obtained by injecting thymulin into the pituitary, though thymulin treatment in the pituitary resulted in a higher number of ova shed and lower follicular atresia. Conclusion: The present results suggest that thymulin acts at the medial hypothalamus level, facilitating the release of GnRH and at the pituitary level regulating gonadotrophin release.
El análisis del discurso en el aula define tipologías de intercambios mediadas a través de las relaciones e interacciones entre maestros y alumnos, en forma de secuencias Intervención-Respuesta-Evaluación/Feedback (IRE/F) y Pregunta-Evaluación Feedback (PE/F), las cuales permiten dar cuenta de diversos aspectos de la construcción conjunta del conocimiento y su influencia en el aprendizaje. El objetivo de esta investigación fue analizar las formas de participación de los alumnos a través de las secuencias IRE/F y PE/F durante prácticas clínicas mediante el programa informático SDIS-GSEQ. Participaron 30 estudiantes de segundo semestre, cinco practicantes de octavo semestre y una maestra, todos pertenecientes a la licenciatura de enfermería en la Facultad de Estudios Superiores-Iztacala. Analizando los flujos de discurso se encontró la existencia de secuencias IRE/F completas e incompletas, post-expansiones y secuencias PE/F. Se observó que los alumnos son responsables activos de su conocimiento y son capaces de adquirir patrones de discurso del experto para dar retroalimentación a sus iguales.AbstractDiscourse analysis in the classroom defines types of exchanges mediated through the relationships and interactions between teacher and students, in the form of sequences Initiation-Response-Evaluation/Feedback (IRE/F) and Question-Evaluation/Feedback (PE/F), which allow to account for various aspects of the joint construction of knowledge and its influence on learning. The objective of this research was to analyze different ways of students’ participation through IRE/F and PE/F sequences during clinical practice by SDIS-GSEQ software. 30 students from second semester, 5 practitioners from eight semester and a teacher, all of them belonging to Facultad de Estudios Superiores-Iztacala Nursing Degree, participated in the study. By analyzing speech flux we found the existence of complete and incomplete IRE/F sequences, post-expansion and QE/F sequences. It was noted that students are responsible for their knowledge and are able to acquire speech patterns from the expert to give feedback to their peers.Recibido: 21 de junio de 2016Aceptado: 08 de diciembre de 2016
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