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Biomedical subjects

G Tolis

Publications and source records attributed to G Tolis.

At least 73 records · Page 4Linked to original sources
PubMed1981

Effect of clonidine on growth hormone and glucagon secretion.

The effect of clonidine (0.15 mg i.v.) on circulating GH, glucagon and glucose concentrations was measured in six normal subjects. GH and glucose increased but glucagon secretion remained unchanged. These data indicate that in man clonidine-induced GH secretion is not mediated by a stimulatory effect of clonidine on glucagon secretion and that alpha-adrenergic mechanisms have little role in the regulation of basal glucagon secretion.

Adult↗
PubMed1981

Suppression of androgen production by D-tryptophan-6-luteinizing hormone-releasing hormone in man.

Four male transsexual subjects were given a superactive luteinizing hormone-releasing hormone (LHRH) analogue, D-tryptophan-6-LHRH at daily doses of 100 micrograms for 3--6 mo. A decrease in beard growth, acne, and erectile potency was noted; the latter was documented objectively with the recordings of nocturnal penile tumescence episodes. Plasma testosterone and dihydrotestosterone levels fell to castrate values; basal prolactin and luteinizing hormone levels showed a small decline, whereas the acutely releasable luteinizing hormone was significantly suppressed. A rise of plasma testosterone from castrate to normal levels was demonstrable with the use of human chorionic gonadotropin. Discontinuation of treatment led to a normalization of erectile potency and plasma testosterone. The suppression of Leydig cell function by D-tryptophan-6-LHRH might have wide application in reproductive biology and in endocrine-dependent neoplasia (where it could replace surgical castration).

Adult↗
PubMed1981

"Torsades de pointes" invariant angina: successful treatment with verapamil.

A patient had continuous paroxysms of the specific ventricular arrhythmia of the "Torsades de Pointes" type during attacks of variant angina. The arrhythmia was refractory to lidocaine and procainamide and only responded dramatically to verapamil, initially intravenous and afterwards oral. The low success rate in the treatment of such arrhythmias by other drugs and available experimental data suggest that verapamil should be further evaluated.

Administration, Oral↗
PubMed1980

Pituitary apoplexy. The importance of skull roentgenograms and computerized tomography in diagnosis.

In two patients with pituitary apoplexy, computerized tomograms demonstrated a suprasellar mass that, after infusion with contrast medium, showed a peripheral ring-like enhancement consistent with a pituitary adenoma with central necrosis. In patients with symptoms or signs suggesting subarachnoid hemorrhage or meningitis, the finding of an enlarged sella turcica on plain skull roentgenograms should raise the possibility of pituitary apoplexy. This diagnosis may be rapidly and safely confirmed by computerized tomography.

Adult↗
PubMed1980

Friedreich's ataxia and oral glucose tolerance: I. The effect of ingested glucose on serum glucose and insulin values in homozygotes, obligate heterozygotes and potential carriers of the Friedreich's ataxia gene.

Glucose tolerance and insulin release were evaluated in 16 families with Friedrich's ataxia. Impaired glucose tolerance differed in incidence according to the method of evaluation, but was increased in number in parents and siblings of Friedreich's cases. Insulin output was not quantitatively different from normal, although the insulin peak was often delayed. This finding, in association with impaired glucose tolerance, suggest a defect in glucose entry into cells.

Adolescent↗
PubMed1980

Friedreich's ataxia and oral glucose tolerance: II. The effect of ingested glucose on serum growth hormone in homozygotes, obligate heterozygotes and potential carriers of the Friedreich's ataxia gene.

Homozygotes, obligatory heterozygotes and potential carriers of the Friedreich's Ataxia gene were tested with an oral glucose tolerance in order to assess a. the prevalence of abnormalities in glucose handling, b. the secretory pattern of two "diabetogenic" hormones, growth hormones and prolactin and c. to evaluate the possibility for detection of an abnormal trend in these hormones to be used as a genetic marker. Despite the high prevalence of glucose abnormalities horizontally and vertically in these families, the basal output and responses of these metabolic hormones to a glucose challenge were appropriate and thus not characteristic of any of the above groups.

Adolescent↗
PubMed1980

Prolactin: Physiology and pathology.

In part, prolactin controls its own rate of secretion through negative feedback mechanisms, but complex interactions of prolactin inhibiting and releasing factors also are involved. Hyperprolactinemia is the most common result of neuroendocrine management are described for various hyperprolactinemic states.

Adenoma↗
PubMed1980

[Echocardiography of the communication between the left ventricle and the right atrium. A surgical case].

The echocardiographical appearances in left ventricular--right atrial communication are described in a patient who later underwent surgery. Cross-sectional echocardiography was most valuable. It provided an immediate diagnosis and also localised the site of the malformation which had been suggested indirectly by the appearances on M-mode scanning. The success of reparatory surgery was confirmed by the same method.

Child↗
PubMed1979

Divorce and remarriage in a 65-year-old male following transphenoidal surgery and bromocriptine of hyperprolactinemic impotence: a dilemma.

Hyperprolactinemia, hypogonadotropinism, and subnormal plasma testosterone were found in a 65-year-old patient who had an enlarged sella turcica, complained of fatigue, and addmitted to decreased sexual interest and potency. Selective nontotal tumorectomy followed by bromocriptine therapy resulted in normoprolactinemia, increased plasma testosterone, and "rejuvenation difficult to follow" according to his wife. This patient described his sexual status as comparable to that of age 24 when he fathered his only child. Both wife and husband attributed the changes to bromocriptine and requested discontinuation (wife) and continuation (husband) of the treatment; because of the clinical indications, treatment was continued. Legally, a medical certification of a normal state of health was required before divorce--and subsequent marriage to a young woman--were permitted.

Bromocriptine↗
PubMed1979

Pharmacology of bromocriptine in health and disease.

Bromocriptine, a lysergic acid derivative with a bromine atom at position 2, has been found to have unique effects on the dopamine receptors in the pituitary and central nervous system and peripherally. It is rapidly and completely absorbed from the gut and is mainly excreted in the bile and faeces. It seems to have a particular specificity for the pituitary prolactinotrophe although it does have other effects in different diseases states. In spite of the fact that it is an ergot derivative, it is remarkably free of ergot vascular side effects in the doses needed for therapeutic benefit. The most common adverse effect are nausea, vomiting and postural symptoms. These can be overcome by starting at low doses and increasing the therapeutic levels. Its major use is in the suppression of prolactin in states where this hormone is elevated irrespective of cause. It has also been used in the treatment of acromegaly and is under investigation for use in other disease states probably linked with prolactin system or dopaminergic receptors.

Adrenocorticotropic Hormone↗
PubMed1979

Episodic and TRH induced growth hormone release in primary hypothyroidism of man and rat.

In 27 hypothyroid subjects studied over 20 to 120 minutes, the concentration of serum growth hormone (GH) was variable with the amplitude and frequency of the secretory patterns similar to those reported by others for normal individuals. Serum GH, after the administration of thyrotropin releasing hormone (TRH) did not differ from values observed as spontaneous surges, in contrast to a consistent increase in thyrotropin and prolactin. Episodic secretion of GH persisted in thyroidectomized rats and did not differ significantly from that present in intact controls. It is concluded that episodic GH secretion is not abolished in primary hypothyroidism and that TRH is not a constant GH secretagogue in human subjects with hypothyroidism.

Adolescent↗
PubMed1979

Prolonged amenorrhea and oral contraceptives.

Of 106 consecutive women referred for secondary amenorrhea of more than 1 year's duration, 65 were diagnosed as having functional amenorrhea. Of these 65, 29 had amenorrhea directly following discontinuation of oral contraceptives (OC group) and 36 had never used oral contraceptives (NOC group). There was no difference in the incidence of prior menstrual irregularity in either group. Similarly, there was no difference in the resting serum estrone, estradiol, luteinizing hormone, follicle-stimulating hormone, and prolactin levels between the OC and NOC groups. Nor was there a difference between the OC and NOC groups in response to medroxyprogesterone acetate, clomiphene citrate, or luteinizing hormone-releasing factor. Of 106 patients, 17 were proven to have prolactinomas. Eight patients had a prior history of OC use, whereas nine did not. With the exception of elevated serum prolactin levels, there were no significant differences in biochemical tests or history of oral contraceptive use between the prolactinoma group and patients with prolonged "functional" amenorrhea (OC plus NOC groups). The lack of historical or biochemical difference between the OC and NOC subjects indicates homogeneity between groups, and does not support the existence of a "postpill" syndrome.

Adult↗
PubMed1979

Seminal fluid prolactin: studies in normal subjects and in hypergonadotropic oligospermia.

A sensitive radioimmunoassay was developed for the determination of seminal plasma prolactin levels. Prolactin added to normal or oligospermic seminal plasma was fully recoverable, indicating that the seminal plasma of oligospermic patients did not contain interfering substances. A gradient between seminal plasma blood serum prolactin was found in 54 health fertile subjects. No gradient was demonstrable among 13 infertile oligospermic patients who had normal levels of serum testosterone and luteinizing hormone but elevated levels of follicle-stimulating hormone.

Follicle Stimulating Hormone↗
PubMed1978

Prolactin-secreting tumors and hypogonadism in 22 men.

We studied 22 men with prolactin-secreting pituitary tumors and hypogonadism. Twenty complained of impotence, nine had visual impairment, and three experienced galactorrhea. None of the 17 patients undergoing operation or radiotherapy, or both, were subsequently normoprolactinemic. In all 13 patients treated with bromocryptine major clinical improvement was associated with a decrease in serum prolactin levels and in nine with an increase in serum testosterone. Two patients receiving testosterone replacement therapy showed improved potency only after bromocryptine was administered. The results indicate that hyperprolactinemia frequently induces hypogonadism in men, that bromocryptine ameliorates symptoms of disease previously unchanged by operation or radiotherapy, and that the impotence observed may not be solely the result of hypogonadism.

Adenoma, Acidophil↗