Biomedical subjects
Publications and source records attributed to T Ionescu.
HBs antigen was determined in 297 members of 91 families, former blood donors in whom the state of HBs antigen carrier lasted more than six months. The results emphasized the higher proportion of HBs antigen carriers in the family environment than in the general population (7.4% as against 4.9%) and the significantly higher frequency of the antigen among the members of consanguine families.
Biological, sero-epidemiological and bacteriological investigations, carried out in the town of Bucharest for evaluating the present diphtheria vaccination programme showed: -- high anatoxin titers, exceeding the titer considered as protective, in the vaccinates ; -- a concentration of the level of the titers of 1--4 AU/ml, in over 62% of the subjects, which means that the protective titer was exceeded 33 to lucru: -- negative Schick reaction, in the mean 95.06%, in the subjects examined during the 1969--1975 period; -- isolation of the Bacillus diphtheriae in a proportion of 0.08%, none of the toxigenic gravis type. The authors, correlating these data, consider the present vaccination calendar too loaded both as number of inoculations and as antigen concentration per revaccination dose, and recommend reconsideration of the vaccination programme.
The hypophyseal human growth hormone (hGH), a Raben type laboratory preparation, was re-evaluated as regards its innocuity for therapeutic use. Besides the usual control tests recommended by the Romanian Pharmacopoeia, the contamination of the hGH for clinical use with acute and slow viruses, was investigated taking into account the withdrawal of this hormone in many developed countries. The contamination was absent both with acute viruses as resulted from hemadsorption on cell cultures and counterimmunoelectrophoresis, and with slow viruses as observed from a two year-follow up of guinea pigs injected intracerebrally with the hGH preparation. Further, the content of the growth hormone itself as well as the contamination degree with other pituitary hormones was examined. The hGH-RIA content was 2.23 +/- 0.13 IU/mg (means +/- SEM), range: 1.38-2.80 IU/mg (1st International Standard hGH 80/505-1982). The prolactin contamination assessed by RIA was 187.34 +/- 37.66 ng/mg hGH, range: 28.44-385.20 ng (International Standard WHO: 80/541). The LH and FSH contamination as quantified by the Isocommerz (DDR) RIA kits was with two orders of magnitude lower than 10 IU-LH/IU-hGH, the upper LH contamination limit considered as acceptable. Moreover, the proportion of the large molecular forms in the lyophilized hGH preparation was investigated by polyacrylamide gel electrophoresis. Corroborating the data obtained by these control tests with our previous experience on 149 pituitary dwarfs treated with this hGH preparation during the interval 1964-1984, resulted minor risks of some dangerous side effects of hGH administration in children with growth hormone deficiency by possible contamination with pathogenic agents or with other disturbing hormones.
Thirty nine patients with abnormal high basal hGH levels were selected and analysed as a part of a retrospective study of the results of 1,500 insulin stimulation tests (IST), applied in children and adolescents with growth deficiency. Their height, weight, and bone age were lower than their corresponding chronological age. Both in girls and in boys groups, responders and nonresponders subgroups were detected as judging by the results of the secretagogue action of insulin on hGH. The hGH basal levels were 43.88 +/- 18.27 microU/ml (X +/- SD) in boys (no = 22) and 56.61 +/- 35.21 microU/ml in girls (no = 17). It is to be noted that the hGH nonresponder group had deeper hypoglycemia at 30 minutes post-insulin injection than the responder group: 53.6 +/- 13.0 mg/100 ml (X +/- SD) vs 66.0 +/- 11.5 mg/100 ml respectively (p less than 0.01). Two siblings, a girl and a boy, had the highest basal and stimulated hGH, either during the IST or starvation. One of them, the boy, during the starvation test, had a paradoxical fall of about two orders of magnitude of the serum hGH 4 hr after basal sample collection. These two siblings are similar to the familial Laron type dwarfism. The possible mechanisms of growth deficiency in children with constant high but variable hGH values are discussed, as well as the aspects concerning the therapeutic ways to improve their linear growth.
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Measurement of osteocalcin (a bone protein containing gamma-carboxyglutamic acid, GLA-P) in the biological liquids and tissues is of interest for studying the mechanisms of bone diseases. It is also helpful in making a diagnosis and in following up the patients with diseases in which the osseous system is affected. Methods have been worked out for isolation and purification of osteocalcin from bovine and rat femur in order to use the purified substance as a starting material for developing radioimmunoassay (RIA) systems for each of these osteocalcins. The work went through the following stages: the processing of the femur bone, preparation of the 200 microns bone powder, demineralization of the powder, and concentration of the bone extract, purification of the extract by molecular exclusion chromatography on Sephadex G-100 and repurification to the product by ion exchanger chromatography in NaCl linear gradient, on DEAE Sephadex A-25. The purity of the substance obtained was tested by disk electrophoresis in polyacrylamide gel. The bovine and rat osteocalcins obtained had the adequate purity for being used as RIA reagents.
Osteocalcin (OC) or the bone protein containing gamma-carboxyglutamic acid (BGP or Gla-P), is a specific and sensitive marker of bone turnover. A radioimmunoassay (RIA) system for human osteocalcin was developed with the sensitivity of 0.5 ng/ml. The osteocalcin was measured in sera from 33 hormonally and/or clinically hypothyroid patients: 12 adult and 21 aged patients. For comparison, blood samples were collected from 14 hormonally hyperthyroid adult patients in whom the OC levels were 16.23 +/- 7.57 ng/ml (mean +/- SD) and from hormonally euthyroid adult patients (previously treated hyperthyroid patients) having OC 9.76 +/- 5.32 ng/ml. Abnormal low OC levels were noted in the hypothyroid adult patients group: 1.04 +/- 0.23 ng/ml by comparison to the hypothyroid aged patients 3.76 +/- 2.38 ng/ml (p less than 0.001). Moreover, great variability of the OC serum levels was observed in the aged group, four patients hormonally eu- or hypothyroid having high OC levels in the range: 13.29-55.45 ng/ml and other three patients although hormonally euthyroid but clinically hypothyroid had low OC levels 0.88-2.27 ng/ml. The abnormalities of the OC levels in hypothyroid adult and aged patients are discussed.
The purpose of this work is to develop the procedures for the preparation of the reagents suitable for the radioreceptor assay (RRA) of human prolactin (Prl). Human purified Prl (NIAMDD-hPrl-16) was labelled with 125I by the Chloramine-T or alternatively by the lactoperoxidase method. As reference preparation we used Prl isolated from the ethanolic step of the routine procedure for the preparation of human growth hormone (hGH) for clinical purposes. The lactogenic receptors were prepared from the pregnant rabbit mammary gland previously stimulated with insulin, cortisone and dried thyroid extract. The final receptor preparations obtained by ultracentrifugation contained 8.85-39.36 mg protein per ml. The prolactin was measured in the human sera and in our hPrl preparations by a double antibody radioimmunoassay (RIA) system using the NIAMDD reagents. We developed a RRA system for hPrl using rabbit mammary receptor preparations with a protein concentration of about 4 mg/ml. The comparative competition showed the same magnitude of the inhibition of the tracer receptor binding of hPrl and hGH. This interference of hGH makes difficult the assessment of the specificity of the hPrl-RRA system otherwise accountable by the structural and/or biological relationship of the three lactogenic hormones: hPrl, hGH and human placental lactogen (hPL). Studies concerning the preparation of a purified and solubilized rabbit mammary receptor and of an antiserum for it are in progress in our laboratory with the objective to provide a useful tool for the investigation of the lactogenic receptor structure and function relationship.
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