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L Simionescu

Publications and source records attributed to L Simionescu.

107 records · Page 6Linked to original sources
PubMedDate not supplied

An improved procedure for the preparation of the human thyroglobulin and the development of a thyroglobulin autoantibody kit.

Human thyroglobulin has various applications as a diagnosis reagent or for studying the physiopathology of the protein and hormonal biosynthesis in the thyroid gland. The previous preparation procedure for isolating the human thyroglobulin currently used in our laboratory, has some inconveniences as regards the low yield and the noxious influence of the ammonium sulfate precipitation upon its molecular integrity. Therefore, we describe an improved fractionation and purification procedure whose main steps are extraction of the thyroid tissue homogenate in 0.15 M NaCl followed by a double gel filtration on Sephadex G-200 column. In this way are obtained thyroglobulins A and B grade using the two chromatographic steps, respectively. Thyroglobulin B grade is further submitted to preparative polyacrylamide gel electrophoresis for separating some thyroglobulin isomers as recognized by other groups using the analytical ultracentrifugation procedure. The different fractionation and purification steps were checked by double diffusion in gel using rabbit anti-thyroglobulin serum and horse antihuman serum protein. The homogeneity and the molecular weight of the different fractions we evidenced were analyzed by the aid of disc and plate electrophoresis in polyacrylamide gel. The authors developed the technique for thyroglobulin autoantibody detection by the passive haemaglutination method using stabilized erythrocytes coated with thyroglobulin A-grade. Thyroglobulin B-grade used as a tracer and a reference preparation in a RIA system offered a sensitivity of 1.5 micrograms/liter for thyroglobulin detection in biological fluids.

Autoantibodies↗
PubMedDate not supplied

The thyroglobulin variations during the thyroid surgery for polynodular goiter, hyperthyroidism and cancer.

A radioimmunoassay (RIA) double antibody system for human thyroglobulin (Tgl) was developed with a sensitivity of 2.5 ng/ml T3 and T4 did not interfere in the antibody Tgl binding. The blood was collected pre-, intra- and 24 hrs post-thyroidectomy from 50 females and 4 males diagnosed as polynodular goiter, hyperthyroidism, chronic thyroiditis and thyroid cancer. The ratios of the intra- and post-operatory values versus pre-operatory values were calculated. The basal values in the patients having thyroid troubles varied within very large limits (two orders of magnitude) and these values could not be clearly correlated to the thyroid pathology, However, in untreated hyperthyroid patients the basal values exceeded 100 ng/ml, while in medullary carcinoma they were near the sensitivity limit of the technique. The intra-operatory values varied within the percentual area (thyroid carcinoma), multiplicative area (polynodular goiter and some cases of hyperthyroidism) and the order of magnitude area (hyperthyroid patients and some of the polynodular goiters). The value of the RIA measurement of the Tgl in the serum as an adjuvant in the post-treatment follow up of thyroid patients is discussed.

Female↗
PubMedDate not supplied

The simultaneous isolation of human pituitary hormones. I. Human growth hormone.

The main purposes of the present work are: a. the preparation of "clinical grade" human growth hormone (hGH), its physico-chemical analysis and the improvement of its solubility for clinical purposes; b. the development of a method for the isolation of high-purity hGH using frozen pituitaries. Nine batches of 20 g acetone powder were processed resulting in 4940 mg of "clinical grade" hGH. Samples of these batches randomly selected were analysed by Sephadex G-100 chromatography and by disc and preparative polyacrylamide gel electrophoresis (PAGE). Lyophilised hGH, soluble in NaCl 0.15 M was prepared and called "Hormcresc" and directions for use were elaborated. One hundred frozen glands were processed and the "crude" hGH was purified by gel filtration on Sephadex G-100 and tested using double diffusion in agar gel, radioimmunoassay (RIA), rechromatography on Sephadex G-100 and disc PAGE. The experiments led to an extraction yield of 550 +/- 165 (means +/- SD) mg "clinical grade" hGH per 20 g of acetone powder. The elution pattern of Sephadex G-100 chromatography and of preparative PAGE as well as the pattern of disc PAGE showed that the "clinical grade" hGH is similar to the already known GH hormones: Raben Somatrotropin, Crescormon (Sweden) and hGH (FRG) but different from Sotropin-H (DDR). The "clinical grade" hGH in lyophilised form is similar to the GH preparations accepted by the European pharmacopoea; it is soluble in NaCl 0.15 M and painless on injection by comparison to hGH in powder form. A method was worked out for the extraction, isolation and purification of "highly pure" hGH using frozen pituitaries, which made it possible to isolate from the same batch of glands not only hGH but also luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin and thyroid stimulating hormone (TSH). During the purification of "crude" hGH on Sephadex G-100 a rather abundant fraction of MW of about 5000-15000 daltons was observed; this fraction, codified provisionally the "X" fraction does not contain hGH, as results from the RIA measurements. On disc electrophoresis, the purified hGH is not homogeneous: behind the main fast band three slower bands are observed. Studies concerning the comparison of our "highly pure" hGH with the hGH preparations recommended by WHO, are in progress in our laboratory.

Chromatography, Gel↗
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

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

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

Mild stimulation of serum immunoreactive insulin (IRI) release following large doses of intravenously given glycine to children of normal pituitary function.

In healthy, sexually immature children of both sexes serum IRI levels rose more than expected from random inter-individual variation (i.e. more than 3 standard deviations of the basal level) in 10 out of 21 subjects loaded by glycine. The IRI release by glycine though moderate and not constant is, however, unquestionable. The growth hormone (GH) secretory response to glycine did not change according to the occurrence and/or magnitude of IRI release. It was concluded that GH and IRI stimulatory properties of glycine given intravenously in large doses are completely unrelated.

Adolescent↗
PubMedDate not supplied

Stimulation of anti-influenza serum antibody formation in the rat using bovine thymus polypeptide extract.

The authors show that a thymus polypeptide extract, TP1, prepared by them has the effedt of stimulating the formation of anti-influenza serum antibodies and do not show antigenic properties. The extract causes increase of serum lymphocytes. Electrophoretic analysis in polyacrylamide gel reveals a number of 11 fraction, while paper chromatography for amino acids, a number of 12 spots.

Amino Acids↗
PubMedDate not supplied

L-proline loading for the assessment of pituitary GH reserve.

Intravenous insulin (0.1 U/kg body weight) and oral 1-proline (100 mg/kg body weight) tolerance tests were performed in 22 healthy and 30 short-statured children and adolescents and blood glucose, serum immunoreactive growth hormone (GH), immunoreactive insulin (IRI) and 1-proline were determined. The peak level of serum GH was significantly higher following insulin than after 1-proline. The proline loading correctly identified the normality of GH axis in 12 out of 22 controls and in 3 out of 7 normopituitary short-statured patients. The serum 1-proline levels consideration did not improve much the ability of 1-proline load to detect either the normal GH responsiveness or the pituitary insufficiency. The mechanism of GH stimulatory properties of 1-proline in some healthy subjects is not known.

Blood Glucose↗
PubMedDate not supplied

The influence of "selenium organicum" upon the hepatic function of carbon tetrachloride poisoned rats.

The hepatoprotective action of the Romanian preparation Orgasel containing selenium (Se) 5.01 mg/100 g autolysated yeast powder, was tested on adult Wistar rats poisoned with carbon tetrachloride (CCl4). The hepatotoxic agent (a 20% CCl4 solution in oil) was administered i.p. in a single dose of 0.3 ml CCl4 solution/100 g body weight, and the preparation tested (autolysate of seleniated yeast) was administered by gavage in 4 doses (of 100 mg Se powder/100 g animal each) along 2 days. After 48 hrs the animals were sacrificed, then their blood and liver were collected. The treatment with Orgasel significantly reduced the organs, morphological changes (fat liver degeneration, splenomegaly, testicle degeneration) induced by CCl4 poisoning in the rat, an effect found also at the biological parameters levels studied in plasma and liver. In the plasma, the high lipid peroxide concentrations, the increased activity of alkaline phosphatases, and the reduced antioxidative activity generated by CCl4 have been statistically significant brought to the normal range after Orgasel administration. At the liver this treatment significantly decreased the lipid peroxides production, the total lipids and cholesterol concentrations, and statistically significant increased the enzymes activity (alkaline phosphatases, GPT). The results obtained after Orgasel administration proved that this preparation has a global beneficial action upon the organism in the poisoned rat, as well as a strong antioxidative effect, confirming once again the essential role of Se in maintaining cells' integrity.

Animals↗
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↗
PubMedDate not supplied

Child with 46, XY/46, XY, 18p- mosaic.

A 46, XY/46, XY 18 p-mosaic was encountered in a child with cranio-facial dysmorphia, anomalies of the fingers, metaphyseal and epiphyseal dysgenesis, psycho-motor backwardness, anomalies of EEG and convulsions.

Craniofacial Dysostosis↗