Biomedical subjects
Publications and source records attributed to A G Del Rio.
Mature Bufo arenarum eggs, as well as body cavity oocytes of the same species, have been found to be fertilizable under anaerobic conditions. Anaerobic fertilization was obtained in a medium in which oxygen was replaced by purified nitrogen and in the presence of antimycin in concentrations assuring the complete blockage of respiration.
Thyroid hormones play an important role in epididymal function. Hypothyroid animals experience a significant decrease in the number and forward motility of sperm and a remarkable impairment of epididymal morphology. However, it is yet unknown if such activity is due to direct actions of iodothyronines on the target epididymis. The eventual identification of T3 receptors in the nucleous of epididymal cells becomes relevant. For this reason, the authors searched for specific high-affinity binding of T3 to these nuclei. Twenty prepuberal male Wistar rats were used. The testes and epididymis were approached as one unit through a scrotal incision. The fat-free epididymides were subjected to standard techniques to prepare the nuclei for incubations with 125I-T3 concentrations, ranging from 0.5 x 10(-9) to 2.0 x 10(-11) M. Calculations of association constants and binding capacities were performed according to Scatchard. A single binding site with a Ka of 3.06 +/- 0.6 x 10(9) M(-1) or Kd of 3.26 +/- 0.6 x 10(10) M and a maximal binding capacity of 0.11 +/- 0.02 pmol T3/microg DNA were observed. It is concluded that these nuclei contain a specific T3 receptor. This finding strongly suggests that thyroid hormones have direct effects on the epididymis.
The purpose of this research was to investigate, using scanning electron microscopy, the effect of hypothyroidism on the ultrastructure of the rat cauda epididymis. Thyroidectomy was obtained by ip injection of 270 muCi of 131I per rat. One month later, several portions of cauda epididymis were examined. Morphological and physiological differences were detected in the cauda epididymis of the hypothyroid animals when compared to the control normal rats. The hypothyroid condition was associated with important changes in the luminal surface of the cauda epididymis epithelium. Broken, oblique, and loss of stereocilia, denuded epithelial cells, and flattening of the tubule were observed. The results confirm that hypothyroidism causes marked structural changes in the cauda ductus epididymis and could be adversely affect sperm maturation motility.
The purpose of this research was to investigate the effect of hypothyroidism on the ultrastructure of the rat cauda epididymis. Thyroidectomy was obtained by i.p. injection of 270 microCi of 131I per rat. One month later, several portions of cauda epididymis were examined in an electron microscope. Morphological and physiological differences were detected in the cauda epididymis of the hypothyroid animals when compared to the control normal rats. The hypothyroid condition was associated with a decrease in the height of the cells and diminution of the internal lumen, number of mitoses, and chromatin decondensation. Hypothyroidism produces a remarkable impairment of epididymal morphology that could be mainly responsible for the functional alterations that lead to the dramatic slowing of spermatozoa motility, commonly seen in severe thyroid insufficiency.
The purpose of this research was to investigate the effect of hypofunction of the thyroid gland, caused by radioactive suppression of the gland, on the pattern of spermatozoa motility in different segments of the rat epididymis. Thyroidectomy was obtained by i.p. infection of 270 microCi of I-131. After about 30 days, the animal reached hypothyroidism as determined by serum level of T4. When the motility pattern of the sperm obtained from the epididymis of normal rats was compared to that of hypothyroid animals, a drop in the parameter of path velocity (VAP), progressive velocity (VSL), and track speed (VCL) were detected. Hypofunction was associated with decreasing sperm motility in the epididymis. In thyroidectomized rats injected with T4, no sperm motility changes were observed.
The purpose of this research was to investigate, using light, transmission, and scanning electron microscope, the effect of hypothyroidism on the ultrastructure of the rat epididymis. Thyroidectomy was obtained by ip injection of 270 microCi of (131)I per rat. One month later, several portions of cauda epididymis were examined. Morphological differences were detected in the epididymis of the hypothyroid animals when compared to the control normal rats. The hypothyroid conditions were associated with important changes in the epididymis. The light observations showed cells with clearing of the chromatin and increased density and thickness of the chromatic rim, chromatinic net, and disappearance of the segment of the chromatin rim. In the scanning electron microscope broken, oblique, denuded epithelial cells with loss of stereocilia were observed, as well as flattening of the tubule. The hypothyroid condition under transmission electron microscope was associated with a decrease in the height of the cells, diminution of the internal lumen and number of mitoses, and decreased chromatin decondensation. Results obtained confirmed that hypothyroidism causes marked structural changes in the ductus epididymis and could adversely affect the maturation and motility of sperm.