Biomedical subjects

A Capaldo

Publications and source records attributed to A Capaldo.

4 recordsLinked to original sources

PubMed2003

Shift from noradrenaline to adrenaline production in the adrenal gland of the lizard, Podarcis sicula, after stimulation with vasoactive intestinal peptide (VIP).

The aim of this study was to investigate the distribution and function of VIP in the adrenal gland of the lizard, Podarcis sicula. We have shown by immunohistochemistry that VIP fibers were localized exclusively around clusters of chromaffin cells in the dorsal ribbon of the lizard adrenal gland. Moreover, a strong positivity for this peptide was observed within ganglial cells and within most chromaffin cells of the gland. To investigate the effects of VIP on the adrenal gland, we have treated lizards with several doses of this peptide and we have shown that injections of exogenous VIP increased plasma levels of catecholamines and corticosteroids, but not of ACTH. This probably suggests a direct effect of VIP on the control of adrenal hormone secretion without the involvement of the hypothalamo-hypophyseal axis. Our results also establish that the increased levels of the hormones were modulated in a time- and dose-dependent manner. Therefore, our morphological studies showed a clear increased function of steroidogenic cells. In the medullary region, VIP administration induced not only a functional enhancement of adrenaline release from adrenergic cells, but also a shift of noradrenaline cells to adrenaline ones.

Adrenal Cortex Hormones↗

PubMed2000

Inhibin in the testis and adrenal gland of the male lacertid, Podarcis sicula Raf.: a light immunocytochemical study.

Inhibin is a glycoproteic hormone mostly produced by the gonads. Through a feedback at the pituitary level, it selectively inhibits the release of follicle-stimulating hormone. In mammals, inhibin has been found also in some extragonadal tissues such as placenta, pituitary, adrenal, spleen, kidney, brain and spinal cord. At present, no information is available about the existence of inhibin in reptiles. The aim of the present work is to localise, through immunocytochemical methods, the sites of inhibin production in male lizards during the main phases of the reproductive cycle: the culmination phase (April-June), the early regressive phase (early July), the maximal regressive phase (August) and the winter stasis (January). In the testis, immunostaining is mainly localised in the Leydig cells during the early regressive phase, while it is observed in the Sertoli cells during the maximal regressive phase. In the epididymis, the immunostaining is present only during the reproductive period at the level of secreting cells and inside its ducts. In the adrenal gland, after immunostaining, both chromaffin and steroidogenetic tissues are inhibin-positive during the whole spermatogenetic cycle, though with variable intensity throughout the year: cross-reaction appears more evident from January to April (winter stasis and culmination phase) and weaker in June. However, in captive animals, the reaction persists in chromaffin cells, but disappears in steroidogenetic cells. The functional meaning of the presence of inhibin as a factor in the local regulation of spermatogenesis is discussed.

Adrenal Glands↗

PubMed1998

Optical coherence tomography.

The optical coherence tomograph is a new, noninvasive technical device that can obtain cross-sectional, high-resolution images-optical coherence tomographs (OCT)-of the retina. This instrument permits an accurate evaluation of various macular and chorioretinal pathologies and the early detection of glaucomatous damage. Images of the retina are obtained similar to ultrasound B-scan, with 10-microm longitudinal resolution. Because the OCT operates with a near-infrared wavelength (about 840 nm), the examination is of minimal discomfort for the patient. OCT examination is indicated in cases of macular pathologies such as vitreoretinal interface syndrome, in the early detection and quantitative assessment of macular edema, and in the evaluation of a glaucomatous damage by measuring the retinal nerve fiber layer thickness. The future role of this instrument and its applications for clinical diagnosis depend on the future improvement and updating of the software.

Humans↗

PubMedDate not supplied

Endocrinologic effects of the anaesthetic propofol.

Because of the similarities of the adrenal glands of mammals and of the lizard Podarcis s. sicula, the latter has already been the subject of various studies on the effects of Propofol and other anaesthetics. Because a relationship between the activities of the thyroid and adrenal glands of this species has been demonstrated, the authors administered Propofol to a species of lizard to investigate its effects on the thyroid gland. Propofol inhibited thyroid activity, promoted steroid synthesis, and caused the contemporaneous appearance of both adrenaline and noradrenaline granules in the cytoplasm of the chromaffin cells. These results suggest that inhibition of the activity of the thyroid gland is secondary to the action of Propofol on the adrenal gland.

Adrenal Glands↗