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Biomedical subjects

F Drago

Publications and source records attributed to F Drago.

At least 217 records · Page 12Linked to original sources
PubMed1981

In vivo and in vitro interference of phosphatidylserine liposomes on prolactin secretion in the rat.

The effect of sonicated suspensions of phosphatidylserine (PS), an acidic phospholipid, was investigated on prolactin secretion utilizing in vivo and in vitro approaches. Acute and chronic administration of PS reduced plasma prolactin levels during different phases of circadian rhythms. The phospholipid was able to inhibit the plasma prolactin surge, which occurs in cycling female rats on the afternoon of proestrus. The time course of PS on prolactin secretion was characterized by a short latency (15 min) and a long duration of action (6 h). In rats with hypothalamic deafferentation PS partially reduced the increase of circulating prolactin induced by pretreatment with alpha-methyltyrosine. An inhibition of prolactin release was observed if anterior pituitary glands were incubated in presence of PS. This effect was prevented by the addition of the dopamine antagonist sulpiride to the medium. In conclusion, PS decreases prolactin secretion both in vivo and in vitro. The inhibition of the hormone secretion appears to be due to the action of PS at the level of the pituitary; however, a concomitant stimulatory action on the turnover of the tuberoinfundibular neurons cannot be ruled out.

Animals↗
PubMed1981

Serotonin nerve endings and regulation of pupillary diameter.

On the basis of the effects caused by 5-6-dihydroxytryptamine (5-6-DHT) on the serotonin nerve endings (chronic degeneration with depletion of the mediator), the eventual existence of serotoninergic fiber regulating pupillary diameter (PD) and intraocular pressure (IOP) was studied from a functional point of view. For the miotic effect found after administration of 5-6-DHT in rabbit, not accompanied by any change in the IOP, the hypothesis of a coparticipation of the serotoninergic fibers in the regulation of the PD is proposed, thus sustaining the concept that both PD and IOP respond to mechanisms of autonomous control. A phenomenon of receptorial supersensitivity to serotonin after the lesion of the nerve endings, dependent on 5-6-DHT, was also encountered.

5,6-Dihydroxytryptamine↗
PubMed1980

Endocrine optic neuropathies.

Optic neuropathy is found as a primary disorder in a number of endocrinological diseases. The authors discuss in this respect dysfunction of the thyroid, parathyroid, suprarenals, pancreas, ovarian and hypophysis.

Adrenal Gland Diseases↗
PubMed1980

Opiate receptors in the rabbit iris.

Evidence pointing to the presence of opiate receptors in the rabbit iris was obtained in an in vivo study of the effects on the pupil of the intraocular injection of morphine (10--100 micrograms) and D-Ala2-met-enkephalinamide (D-Ala-E) (5--50 micrograms). Both opiates induced a significant dose-dependent decrease in pupillary size and an appreciable fluctuation of pupillary size. I.v. administration of naloxone (0.5 mg/kg) before or after injection of opiates prevented the miotic effect and the fluctuation of pupil size. The parallelism of the dose-response curves of opiates in the presence and absence of naloxone indicated competitive reversible antagonism.

Animals↗
PubMed1980

Sexual dimorphism in passive avoidance behavior of rats: relation to body weight, age, shock intensity and retention interval.

Female rats were inferior to age- and weight-matched males in the retention of a step-through type passive avoidance response 24 and 48 hr after the learning. This sex difference could be observed at different intensities of foot shock which was used as aversive stimulus during the single learning trial. Additionally, unlike in males, retention of the passive avoidance response in the females was not the function of shock intensity. Male and female rats, however, showed similar passive avoidance if tested immediately after the learning trial. The results suggest the existence of sexual dimorphism in memory processes.

Age Factors↗
PubMed1980

Plasma concentrations of amitriptyline during single nightly and thrice daily administration. Cross-over study.

Plasma amitriptyline and nortriptyline concentrations were measured in ten depressed in-patients after administration of amitriptyline hydrochloride 75 mg in three divided doses or as a single nightly dose. Mean steady state plasma concentrations during the two dosage regimens were similar. Plasma level differences between dosage schedules at sampling times were small and not significant. It was concluded that the single nightly administration of amitriptyline is a helpful therapeutic schedule which can be used instead of the divided dose when the opportunity is given.

Amitriptyline↗
PubMed1979

Chronic degeneration of aminergic nerve endings and blood-aqueous barrier.

Chemical sympathectomy of the anterior segment of the eye was performed in rabbits with 6-hydroxydopamine (6-OHDA) intravitreously injected. The response of the pupillary diameter (PD) and intraocular pressure (IOP) to NE, E and Isoproterenol was determined through instillation of the drugs in the pretreated and control eyes. The results were as follows: 1) Both PD and IOP at different intervals of time from the injection show a sharp decrease in the treated eye. 2) About four weeks after the injection, the instillation of NE and E increases the PD only in the 6-OHDA pretreated eyes, while IP administration is not effective on both control and pretreated eyes. 3) The instillation of the three drugs, while decreasing IOP in the control eyes, does not modify the already low IOP in the pretreated eyes. The authors suggest the presence of a postdenervation supersensitivity affecting only the alpha receptors, since the beta stimulant IP is inactive in both treated and untreated eyes.

Animals↗
PubMedDate not supplied

Amiodarone used alone or in combination with propranolol: a very effective therapy for tachyarrhythmias in infants and children.

The aim of the study was to evaluate the efficacy of amiodarone used alone or in combination with propranolol in infants and children affected by life-threatening or drug-resistant tachyarrhythmias. The study included 27 children (median age 3 months), affected by life-threatening and/or drug-resistant supraventricular or ventricular tachyarrhythmias. The loading dose of amiodarone was 10-20 mg/kg/day and the maintenance dose ranged between 3 and 20 mg/kg/day. When amiodarone was ineffective, propranolol was added at a dosage of 2-4 mg/kg/day. The study population was divided into two groups: group A was composed of patients <1 year and group B of patients >1 year. The effectiveness of the therapy was assessed by clinical evaluation, Holter monitoring, exercise testing, and, in patients with reentry tachycardias, electrophysiological testing. Amiodarone used alone was effective or partially effective in 4/14 (28%) patients in group A and in 11/13 (85%) patients in group B (p < 0.006). Among amiodarone-resistant patients, the combined therapy with propranolol was effective in 8/10 patients in group A and 2/2 patients in group B. Therefore, amiodarone used alone or in combination with propranolol was effective in 25/27 (93%) patients. During the follow-up (20.5 +/- 13 months) there were no arrhythmic effects but side effects were noted in 5/27 (18.5%) patients. Amiodarone seems to be an effective drug in the control of the life-threatening and/or drug-resistant supraventricular and ventricular tachyarrhythmias in children. The addition of propranolol can significantly enhance the success rate of this class III drug, especially in the treatment of reentry tachycardias due to accessory pathways.

Adolescent↗