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Biomedical subjects

G Delfino

Publications and source records attributed to G Delfino.

50 records · Page 3Linked to original sources
PubMed1982

Development of cutaneous glands in Salamandrina terdigitata (Lacépède, 1788) (Amphibia: Urodela); findings by light and electron microscopy.

Cutaneous glandular Anlagen in Salamandrina terdigitata appear in the early larval stages as sphere-shaped intraepidermal cell nests. A stromal screen rises into the epidermis from the primordial dermis surrounding the Anlagen and isolates them from future keratinous elements. At this stage the only contact between the stroma and the gland blastocytes is through their cell coat, whilst the adjacent keratinocytes show a complex dermo-epidermal type junction. This structural asymmetry, confirmed by cytochemical findings, plays a direct role in guiding processes governing glandular bud differentiation. Interactions are in fact established between the stroma and the ample portion of the Anlage which it surrounds, which coordinate development, initiating differentiation of the contractile and secretory elements. Only a few bud cells, grouped below the epidermal basal layer, avoid such contact with the dermis, and constitute the regenerative matrix of the gland by maintaining their indifferentiated state. Above these, several keratinocytes form the excretory duct.

Animals↗
PubMed1981

The effect of laser irradiation on the frog pineal.

The frog pineal is a functional photoreceptor with probable endocrine capabilities. Continuous wave Laser radiation at 514.5 nanometers for 300 sec at 200 mW, as focused on the pineal of the intact frog Rana esculenta to study the functional role of this structure. The investigation was carried out on 80 male specimens - 40 of which were controls - in light and in dark experimental conditions - during the months of March, July and November. The ratio gonad weight/body weight was used to measure the effect of the Laser. The response was consistently similar from control frogs kept in the dark and from Laser-irradiated frogs kept in the light. The same was observed in the opposite situation. Histological examination showed structural modifications of the gonads and skin of Laser-irradiated frogs. These results suggest a functional correlation between the pineal photoreceptor cells and the pineal secretory cells. We hypothesize that the pineal itself might influence gonadal activity through the secretion of an hormone within the third ventricle. The frog's skin did not change colour during the Laser irradiation, we therefore suppose that the structures responsible for the release of the hormone regulating colour changes are not effected by the Laser beam.

Animals↗
PubMedDate not supplied

Systolic time intervals as possible predictors of pressure response to sustained beta-adrenergic blockade in arterial hypertension. A within-patient, placebo-controlled study.

Systolic time intervals (STI) were recorded at rest and during isometric exercise (IHG) in 20 hypertensive outpatients, WHO Stage 1 or 2. In a double-blind crossover study, slow-release metoprolol 200 mg once daily and matched placebo were given for 4 weeks each, at the end of a 2-week placebo washout. Blood pressure and STI were taken in the last day of washout and of either crossover period. Treatment decreased blood pressure and heart rate values at rest and on peak IHG; it didn't modify preejection period index (PEPI), left ventricular ejection time index (LVETI), and their ratio at rest, but decreased the ratio between diastolic blood pressure and PEPI (DBP/PEPI ratio) at rest and on peak IHG and lengthened the PEPI at peak IHG. Resting PEPI values on placebo treatment showed a negative correlation with systolic (r = -0.72) as well as diastolic (r = -0.80) pressure reduction on slow-release metoprolol as compared with placebo treatment. The PEP/LVET ratio at rest on placebo treatment showed a negative correlation with systolic (r = -0.78) as well as diastolic (r = -0.82) pressure reduction at rest on metoprolol compared with placebo treatment. Patients with a resting PEP/LVET ratio less than 0.43 showed a reduction in both systolic and diastolic pressure approximating or exceeding 20 mm Hg, whereas patients with a PEP/LVET ratio greater than 0.47 showed a decrease in systolic and diastolic blood pressure of less than 10 mm Hg. In patients with a PEP/LVET ratio of 0.43 to 0.47 (50% of the trial population), STI didn't show any correlation with the pressure response to beta-blockade. A positive correlation was found between the DBP/PEPI ratio at rest on placebo treatment and systolic (r = 0.56) as well as diastolic (r = 0.76) pressure reduction at rest on slow-release metoprolol compared with placebo treatment. Thus, STI appeared as promising predictors of the magnitude of blood pressure response to sustained beta-blocking therapy in mild-to-moderate essential hypertension, mostly in patients with a resting PEP/LVET ratio less then 0.43 or greater then 0.47.

Adult↗
PubMedDate not supplied

Serous cutaneous glands of the western spade-foot toad Pelobates cultripes (Amphibia, Anura): an ultrastructural study on adults and juveniles.

The venom glands of the western spade-foot toad Pelobates cultripes were studied under light and electron microscopes. The glands exhibit the structural patterns usual in anurans, including the typical secretory syncytium. The peripheral cytoplasm contains a single row of nuclei and secretory organelles related to proteosynthesis. The inner cytoplasm is filled with large vesicles holding a thin product which originates from the merging of smaller ones containing a thicker material derived from the Golgi apparatus. The appearance and maturation of P. cultripes venom have been compared with patterns of biosynthesis and secretory evolution described in serous cutaneous glands of several anuran species. Following these criteria, the traditional trends in the terminology and classification of serous glands in anuran skin are discussed and reviewed.

Amphibian Venoms↗