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Biomedical subjects

M Oprescu

Publications and source records attributed to M Oprescu.

63 records · Page 4Linked to original sources
PubMedDate not supplied

Labelling of octapeptide neurohormones for in vitro studies. Radioimmunologic assay for arginine-vasopressin.

Synthetic arginine-vasopressin (AVP), oxytocin (OXY) and arginine-vasotocin (AVT) were labelled with radioiodine at a moderate specific activity. The purity of the labelled octapeptides was checked by descendent paper chromatography in butanol-acetic acid-water (4 : 1 : 5 v/v) after a double filtration on a Sephadex G-25 column of the labelling mixtures. The rabbit anti-AVP serum bound 125I--AVP, the highest binding belling observed on the descendent eluates from the Sephadex column. The antiserum is specific to AVP, no binding being observed will AVT or oxytocin. The sensitivity of a RIA system using 125I--AVP, commercial anti-AVP serum and polyethyleneglycol separation technique, was of 5 pg/ml in terms of AVP with a biological activity of 385 IU/mg. The validity of the assay was tested on five patients (two with diabetes inspidus (DI) and three with other endocrine diseases) submitted to dehydration of hydration tests.

Arginine Vasopressin↗
PubMedDate not supplied

Blood-cerebrospinal fluid barrier for prolactin in empty sella syndrome.

In six patients with "empty sella" syndrome (ESS), three primary (pESS) and three secndary (sESS), the ratio of serum to cerebrospinal fluid (CSF) concentrations of prolactin (PRL) was 6.6 +/- 0.7 (mean +/- SEM) (range 5.5--9.6), with a significant correlation between serum and CSF levels of PRL (r = 0.93 p less than 0.01). A control group of ten normal subjects showed similar values. The hyperprolactinemia found in two cases of pESS did not change the serum/ CSF ratio of PRL. The acute release of PRL into the serum following TRH i.v. did not increase the PRL level in CSF either in control subjects or ESS, with one exception. In a case of sESS consecutive to the treatment with bromocriptine (for 6 months) of an invasive prolactinoma, TRH i. v. released PRL into the CSF but not into the blood, and the serum/ CSF ratio of PRL was very low, until a new cure with bromocriptine (for 3 months) mormalised it. It is suggested that the blood-CSF barrier for PRL is similar in ESS and in normal subjects, with the exception of sESS following incomplete remission of some invasive prolactinomas, in which the high permeability of BCB may be explained both by hemodynamic changes in the pituitary portal vascular system and by a new source of PRL which release it directly into the CSF, bypassing the blood route.

Adolescent↗
PubMedDate not supplied

A radioimmunoassay system for human thyroglobulin.

A radioimmunoassay (RIA) system for thyroglobulin (Tgl) was developed. The crude Tgl was prepared from thyroid glands surgically removed for colloid goiter by ammonium sulphate fractionation. Two purified Tgls were obtained by gel filtration on Sephadex G-200 (Tgl-200) and by preparative polyacrylamide gel electrophoresis (Tgl-PAGE). Both Tgl-200 and Tgl-PAGE were used for immunization of the animals for radioiodination and as reference preparations. The double antibody RIA system using Tgl-200 may detect 1.5 microgram/l, the technique being suitable for Tgl quantification in human biological fluids. The results of the measurement in 54 children without apparent thyroid enlargement showed a rather wide range of variability of the Tgl values in basal conditions, for example 4.67-37.05 micrograms/l in a group of 29 boys aged 6 to 16 years and 4.06-31.90 micrograms/l in a group of 25 girls aged 5 to 16 years.

Adolescent↗
PubMedDate not supplied

Inhibitory action of pineal extract on LH and FSH.

The influence of melatonin-free pineal extract on luteinizing hormone (LH) and follicle-stimulating hormone (FSH) was studied. Administration of bovine pineal extract in intact rats was found to induce a statistically significant decrease of serum LH and FSH. The pineal extract also inhibited the 24-hour-post-castration rise of serum and pituitary LH and FSH in mature male rats. The stimulating effect of gonadotropin-releasing hormone (GnRH) on pituitary LH and FSH was also inhibited in intact animals. The antigonadotropic activity of melatonin-free pineal extract, melatonin and arginine-vasotocin (AVT) is discussed.

Animals↗
PubMedDate not supplied

Studies on the action of pesticides upon the endocrines using in vitro human thyroid cells culture and in vivo animal models. II. Herbicides-prometrin and terbutrin.

The effects of prometrin and terbutrin in doses of 0.001--1 mg/1.5 ml culture medium on human thyroid cell cultures were studied following up their influence on cell multipliction, proteic synthesis, enzymatic activity of thyroid cells and hormonal synthesis. The results differed in relation to the dose and the type of thyroid cell under study. The acute experiment performed on rats treated with 50 ppm/prometrin or terbutrin/kg b.w. for 15 days revealed variations in T3, T4 and LH synthesis. Both prometrin and terbutrin stimulate T3 synthesis and inhibit T4 synthesis. LH synthesis appears much increased in the hypophysis of the rats treated with terbutrin, whereas the amount of LH released into the serum is much decreased as compared to the controls.

Animals↗
PubMedDate not supplied

[Hemorrhagic glaucoma].

The hemorrhagic glaucoma defines a clinical syndrome which recognizes as a frequent symptoms the hemorrhagic element, and from the morphopathological point of view the presence of some neoformation vessels at the level of the iris and camerular angle. 22 clinical observations of hemorrhagic glaucoma which appeared during one year are analyzed. It is shown that the new vessels appear as a reaction of the tissues hypoxemia and especially to alon of the oxygen pressure that determines the increase of the vessels. Also in the hemorrhagic glaucoma appears a deficiency of the venous reaction which determines a deficiency of the venous flow. The new vessels appear because of the hypoxemia and acid lactic accumulation only as the presence of a vital iridian tissue, because the new vessels do not appear in necrotic tissues.

Eye Hemorrhage↗
PubMedDate not supplied

The serum and pituitary prolactin variations under the influence of a pesticide substance in the male rat.

Prolactin was measured in the serum and hypophysis of the male rat after five days of oral administration of malathion in suspension (200 mg/kg body), alone or associated with pimozide (a psychotropic drug). The release of prolactin observed in the group treated with malathion was lower (19.97 +/- 7.27 ng/ml) than in the groups treated with malathion and pimozide or pimozide alone (26.65 +/- 3.17 and 26.49 +/- 2.57 ng/ml, respectively) but significantly higher than in the control group (10.08 +/- 5.82 ng/ml). The administration of two dose levels of pure malathion solubilized in alcohol/water (v/v) failed to reproduce the same results. The discussions are focussed upon: 1) the mechanisms involved in the release of prolactin under the influence of malathion (vagomimetic action) and 2) the lack of cumulative effects of malathion and pimozide (presumably different levels of their influence).

Animals↗
PubMedDate not supplied

The release of LH and FSH during the thyroid surgery for hyperthyroidism.

Serial blood samples, collected from 21 females and 9 males through the thyroid surgery procedures were assayed for LH and FSH by a radioimmunoassay (RIA) technique. During thyroid surgery the serum LH increased significantly in the male patients from the preoperative levels 20.66 +/- 11.67 to 45.49 +/- 18.50 mIU/ml (p less than 0.01), being unchanged or slightly lower in the female group. The serum LH progressively fell towards the end of the surgery, remaining over the preoperative levels i4 hrs after surgery; occasionally very high levels were observed. The release of LH seemed to be more precocious during the surgery in both sexes in patients belonging to the age group under 40 years by comparison to the older group. The serum FSH showed nonsignificant changes during and after surgery in both female and male patients excepting two menopaused female hyperthyroid patients and a woman of 60 years under laborious surgery for a cervicothoracic polynodular goiter. The data are suggesting the dissociated secretion of LH and FSH in both sexes excepting some cases of menopaused women.

Adolescent↗