Neuroendocrine cells are present in virtually all organs of the vertebrate body; however, it is yet uncertain whether they exist in the ovaries. Previous reports of ovarian neurons and neuron-like cells in mammals and birds might have resulted from misidentification. The aim of the present work was to determine the identity of neuron-like cells in immature ovaries of the domestic fowl. Cells immunoreactive to neurofilaments, synaptophysin, and chromogranin-A, with small, dense-core secretory granules, were consistently observed throughout the sub-cortical ovarian medulla and cortical interfollicular stroma. These cells also displayed immunoreactivity for tyrosine, tryptophan and dopamine b-hydroxylases, as well as to aromatic L-DOPA decarboxylase, implying their ability to synthesize both catecholamines and indolamines. Our results support the argument that the ovarian cells previously reported as neuron-like in birds, are neuroendocrine cells.

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In mammalian skeletal muscle there are four carboxylases involved in several biochemical processes like gluconeogenesis, tricarboxylic acid cycle anaplerosis, metabolism of fatty acids and metabolism of various amino acids. It has been shown that biotin deficiency reduces body weight at the expense of muscular mass. When necessary, the liver uses skeletal muscle protein to provide glucose and amino acids to organs in need of such compounds. In this paper we analyzed carboxylase specific activities in hind limb skeletal muscle of 3 weeks old BALB/c male mice, at 0, 1, 4, 7, and 14 days of a specific diet with different biotin concentrations. Biotin was used at 0.0, 1.8 or 98.2 mg per kg of food; and was referred to as biotin deficient, sufficient and supplemented, respectively. Water and food supply and consumption by the three groups of mice were the same. Therefore, the observed effects were directly related to biotin ingestion. The body weight of biotin supplemented mice was the same as the body weight of mice in the biotin sufficient group, while biotin deficiency caused body weight reduction after 7 days of biotin depletion. We found that the total protein concentration in the vastus lateralis muscle is associated with the biotin content in the diet. After 7 days, the muscle total protein content was lower in mice of the biotin deficient group while it was higher in the mice from the biotin supplemented group (P < 0.001). Of the four analyzed enzymes, only pyruvate carboxylase specific activity was reduced in both cases: by consuming the supplemented diet and by the lack of this vitamin. Our data show that PC and muscle metabolism are differentially altered by both, biotin excess and biotin deficiency. The mechanisms of these effects are currently under investigation.

A lo largo de los años, me he enfrentado a momentos de desconcierto, principalmente al escuchar a algunos médicos, generales y especialistas, comentar que Embriología es únicamente una “materia filtro” del plan de estudios. Esos momentos han sido motivo de reflexión y como resultado he intentado atender la necesidad de generar competencias en los estudiantes de primer año de la Licenciatura de Médico Cirujano en la Universidad Nacional Autónoma de México (unam); para ello he recurrido al uso de arte pictórico con el fin de favorecer el desarrollo de la capacidad de observación. El estudio secuencial de las obras pictóricas se realiza mediante el diálogo con y entre los estudiantes, mediante preguntas detonadoras. El beneficio para la formación de médicos radica en que, además de fortalecer y afinar la capacidad de observación, los médicos en formación se sensibilizan y se hacen más empáticos con sus pacientes. Aunque la incorporación del arte visual ha sido una de las estrategias con las que he experimentado, como resultado de la reflexión, ha hecho falta evaluar la eficacia en el logro de las bondades descritas por distintos autores con el uso de estas dinámicas de enseñanza en los grupos de estudiantes a mi cargo. En necesario, entonces, diseñar instrumentos de evaluación pertinentes para llevar a cabo la comparación con grupos de estudiantes que hayan revisado los contenidos de la asignatura de una manera tradicional.