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L Simionescu

Publications and source records attributed to L Simionescu.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

The serum osteocalcin levels in adult and aged hypothyroid patients.

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.

1-Carboxyglutamic Acid↗
PubMedDate not supplied

Sleep-induced GH release in otherwise GH deficient children having short stature; a possibly new variant of GH neurosecretory dysfunction (GHND).

Sleep and exercise are considered physiologic stimuli of growth hormone (GH) release from the pituitary. They were used to some extent for the assessment of GH reserve in growth disorders of supposedly pituitary origin. In order to better establish the diagnostic value of the sleep test, we studied 34 children of both sexes aged 6-14 having various degrees of shortness of stature associated with bone age retardation (range of the latter: 3-10 years). Eight healthy controls of the same age were also subjected to the sleep test. The latter was begun at 10:00-11:00 a.m. generally in a dark room under polygraphic control. The subjects were fed a standard breakfast at 8:00-8:30 a.m. After thirty minutes of steep or after reaching the IVth stage of slow-wave sleep, the children were awakened and samples of venous blood for GH determinations were drawn. Two other GH reserve tests were also performed in other days, usually insulin-induced hypoglycemia and glycine intravenous loading. Except sleep, no other GH provocative tests were performed in controls. In normal GH reserve children (21/34) according to other tests, the sleep test was positive (i.e. peak values greater than 15 microU/ml) in 7 cases and the mean GH response was not significantly smaller than the peak recorded after insulin-induced hypoglycemia. In abnormal GH reserve, presumably hypopituitary children (13/34) according to other tests, the sleep confirmed the other tests in 8 cases. In five cases of clinically and endocrinologically "hypopituitary" dwarfism, the sleep test revealed a normal response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Serum-to-saliva transfer of the immunoreactive insulin (IRI) in children with obesity associated with insulin-resistance.

Assuming that the serum-to-saliva transfer of insulin reflects internalization and re-cycling of the hormone in the membrane-located binding sites of salivary epithelial cells and that these cells have in obesity a'marked decrease in insulin receptor content, it has been postulated that insulin resistance in infantile obesity can be detected by the changes in the salivary immunoreactive insulin during the oral glucose tolerance test (OGTT). The study included 31 obese children and adolescents of both sexes, subjected to OGTT. Samples of blood and saliva were collected at 30, 60, 120, 180 and 240 minutes for determinations of glucose and IRI. The blood glucose values were generally normal whereas IRI was excessively high. The dynamics of salivary IRI was similar (easy peak followed by slow descent) with the mean serum values but lower by about two-thirds, and the peak was 30-60 minutes delayed. The serum IRI values correlated significantly with the saliva ones at all time-intervals except for the 30-minute ones. The serum IRI values were significantly lower at the 30-minute time interval, whereas the salivary IRI were the lowest (and of borderline significance) at the 60-min. time interval. The mean glucose/kg doses given orally were not significantly different in the two groups. It was concluded that a hormonal activity detectable by IRI assay through the PEG separation method does exist, with a concomitant variation of serum-to-saliva transfer as shown by the OGTT test. It was also concluded that since the salivary values are lower, the direction of the flow is from serum to saliva and not the reverse. Finally, on the basis of our data, an "in situ" synthesis of insulin (hormonogenic exocrinism) can not be ruled out.

Adolescent↗
PubMedDate not supplied

Radioreceptor assay of human prolactin using rabbit mammary receptors.

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.

Animals↗
PubMedDate not supplied

A heterologous radioimmunoassay system for human osteocalcin. Applications in performance sports girls.

Taking into account the involvement of the measurement of osteocalcin, a protein-containing gamma-carboxyglutamic acid (Gla), in investigating the physiopathology of bone and calcium metabolism, a radioimmunoassay (RIA) method useful in human clinics was developed. The reagents for the RIA of human osteocalcin namely, the radioiodination preparation, the reference preparation and the antiserum were obtained starting from bovine bone on account of the structure similarities between bovine and human osteocalcin. The reagents were incubated at 4 degrees C for 48 h followed by the polyethylene-glycol (PEG) separation technique. The sensitivity of the osteocalcin RIA method is 2.0 ng/ml, the intraassay precision is 3-5% and the interassay precision, 8-12% (coeficient of variation). Osteocalcin was measured in the sera of 3 groups of performance sports girls under basal conditions and being of more or less similar ages: rowing girls (n = 10, mean age 16 yr 6 mos), gymnast girls (n = 13, mean age 14 yr 8 mos) and table tennis girls (n = 9, mean age 16 yr). The same samples were used for the measurement of myoglobin. Osteocalcin quantification showed similar levels in the rowing and the table tennis girls, i.e. 11.91 +/- 3.39 ng/ml (X +/- SD) and 9.50 +/- 4.15 ng/ml, respectively. By contrast, in the gymnast girls, the osteocalcin levels were about 4 times higher (44.31 +/- 7.27 ng/ml) than in the other two groups. Myoglobin measurements showed lower levels in the gymnast group, than in the rowing and the table tennis groups, the latter two having similar levels. The multiplicative increase of osteocalcin in the gymnast girls is interpreted and commented in relation to their age and sexual development.

Adolescent↗
PubMedDate not supplied

A radioimmunoassay system for LH based on the antigenic similitude of LH with HCG: methodology and applications.

A double antibody radioimmunoassay (RIA) system for LH (LH-IEP Kit) was developed using the antigenic similitude of LH with HCG. The first antibody (Ist Ab) is rabbit anti-HCG serum, initial dilution 1:200 000. The tracer is 125I-HCG (code MJ-14 Swierk Poland). The standard curve is calibrated with the reference preparation hLH-Ist-IRP 68/40 kindly offered by WHO. The IInd Ab is pig anti-rabbit IgG serum. The incubation conditions: volume-0.3 ml; time-24 hrs with Ist Ab and 24 hrs with the IInd Ab at ambient temperature. The sensitivity of the RIA system for LH is 1.5 mIU/ml. To validate our RIA system the LH was measured in the serum samples collected from 9 women during the menstrual cycles, from 2 boys during the GnRH test, from 2 amenorrheic women and from 20 children, adolescents and adults with miscellaneous pathologies. In all these samples, parallel measurements of LH and FSH were performed using DDR commercial RIA Kits-SSW. It is to be mentioned that the LH-RIA Kit-SSW is not completely homologous, the Ist Ab being rabbit serum anti-HCG. The results obtained during 4 menstrual cycles, in which the LH peak is observed around the mid point of the interval are: follicular phase 17.92 +/- 5.58 mIU/ml (means +/- SD) with LH-IEP-Kit and 5.51 +/- 2.77 mIU/ml with the LH-SSW-Kit, peak: 26.07 +/- 22.13 mIU/ml and 9.13 +/- 5.60 mIU/ml respectively; luteal phase: 12.55 +/- 5.46 mIU/ml and 3.4 +/- 2.38 mIU/ml, respectively. The LH values observed by the two kits through all 9 menstrual cycles are well correlated ("r" values in the range 0.7-0.9) but high discrepancies were observed in the remaining 3 cycles ("r" between 0.07 and 0.6). These discrepancies as well as those observed in some adolescents with genetic anomalies and in a patient at climacterium are suggesting that the two LH-RIA systems measure not only a common molecular area but also different areas of the LH circulating molecules.

Adolescent↗
PubMedDate not supplied

Radioreceptorassay of insulin using human erythrocytes. I. Methodological aspects.

It is known that human erythrocytes have specific receptors for insulin. This works describes a radioreceptor assay (RRA) suitable for the determination of the insulin binding to the surface receptors of erythrocytes. The erythrocytes were isolated from heparinated blood collected in the morning after overnight fasting. In the incubation mixture are 4-5 X 10(9) cells/ml, labelled porcine insulin and nonlabeled (cold) insulin in serial concentrations, range 10-10(5) ng/ml. Incubation (150 min. at +15 degrees C) is ended by suspending the incubation mixture in cold buffer. After washing, the tracer insulin bound to erythrocytes is measured on a gamma counter and the percentage of the specific binding is calculated against the total radioactivity determined prior to the washing steps. By this procedure, the maximal binding of 125I-Insulin was 10.55 +/- 0.78% (mean +/- SD) in five normal volunteers and 6.79 +/- 1.77 (mean +/- SD) in five obese nondiabetic patients, having an enhanced insulin response in the oral glucose tolerance test. The slight hemolysis that happened accidentally in some tubes after incubation caused rude degradation of the tracer, the binding being decreased at last by 25%. The method described (according to Gambhir K. K. et al 1977 slightly modified) is specific and thus suitable for estimating the prognosis of obese children, patients with acute and chronic hepatitis and also for the study of the role of erythrocytes in insulin metabolism and possibly in the metabolism of other hormones.

Animals↗
PubMedDate not supplied

Peptide hormones in saliva. I. Insulin in saliva during the oral glucose tolerance test in female patients.

The radioimmunoassay (RIA) of insulin was performed in the serum and saliva of 27 female patients during the oral glucose tolerance test (OGTT). The patients were divided into two groups: 19 non-diabetic patients and 8 patients diagnosed as impaired glucose tolerance (IGT) disease. In one patient in each group, the OGTT was performed twice at intervals of 3-5 days. The results show that immunoreactive insulin (IRI) is present in saliva and its concentration increases during the glucose stimulation test from 6.48 +/- 1.13 microU/ml (means +/- SEM) in basal conditions at peak values of 45.46 +/- 10.14 microU/ml at 2 hrs after glucose intake. In patients with IGT salivary IRI increases from 5.18 +/- 1.39 microU/ml in basal conditions to peak values of 83.34 +/- 25.85 microU/ml at 3 hrs after glucose administration. Great response variations were observed either inter-individual or intraindividual in both groups of patients. Some patients had unusual high salivary IRI concentration especially in those with gastrointestinal troubles. Further, some hypotheses and experimental models, are advanced, considered useful for the explanation of the physiologic significance of the salivary IRI or of the IRI-like material.

Adult↗
PubMedDate not supplied

The value of thyroglobulin (TGL) assay in following the post-therapeutic course of differentiated thyroid cancer.

Serum TGL was assayed in 32 patients with total thyroidectomy performed on account of differentiated thyroid cancer, and in whom postoperative serum TGL values were above 60 ng/ml. The purpose of the study was to demonstrate the specific TGL response in differentiated thyroid cancer relapse and metastases, and the value of serum TGL assay as a test for early diagnosis of relapse and metastasis in this form of cancer. The results were compared to those from the following lots: 15 euthyroid volunteers, 15 patients with differentiated thyroid cancer diagnosed postoperatively whose serum TGL values were under 60 ng/ml and, 14 patients with non-thyroid cancer metastases.

Antibodies↗
PubMedDate not supplied

Serum and pituitary prolactin variations under the influence of pyridoxine and pimozide in the male rat.

Prolactin was measured in the serum and hypophyses of the male rat after six days of i.p. administration of pyridoxine 5 mg (group B6), after a single dose of pimozide 2.5 mg/kg body (group PMZ), six days of pyridoxine and one dose of pimozide (group B6- PMZ) and a single dose of tartaric acid (controls). Both pyridoxine and pimozide increased the serum prolactin: 59.06 +/- 16.23 ng/ml and 68.45 +/- 10.78 ng/ml respectively (X +/- DS) by comparison to controls: 33.12 +/- 11.16 ng/ml, their effect being cumulative (83.75 +/- 13.86 ng/ml). However, the effect of pyridoxine and pimozide at the central level is different, pyridoxine producing an increase of the pituitary concentration of prolactin, while pimozide depleted the stored prolactin. Hypothetical mechanisms of pyridoxine action at the pituitary level are discussed.

Animals↗
PubMedDate not supplied

RIA measurement of insulin antibodies in human sera using the polyethyleneglycol separation technique.

A radioimmunological method for the detection and measurement of insulin antibodies in human sera was developed using polyethyleneglycol (PEG) as separation agent. Studies were performed on 150 sera of nondiabetic subjects and on 27 sera collected from diabetic patients treated with insulin. The per cent binding of 125I-insulin in normal sera ranged similarly to control free-insulin serum while in sera from insulin-treated patients8 the binding was significantly greater. The technique is quick (24 hours) and the intra-assay precision (correlation coefficient for replicates) varies from 0.87 to 0.99%. The separation technique using PEG for the precipitation of the antigen-antibody complexes may be extended to the measurement of antibodies for any other substance of lo, molecular weight (under 10,000 daltons).

Antigen-Antibody Complex↗
PubMedDate not supplied

The effect of combined administration of L-proline and glycine on GH and IRI release in healthy prepuberal children.

Proline (100 mg/kg b.w.) was given per os and after 30 minutes 10% glycine was i.v. injected to 25 healthy children of both sexes. A positive response (an increase of over 5 ng/ml of serum level of GH) was found in 21 of the 25 children. The insulin test showed a positive response in 24 of the 25 children. It was concluded that the decrease in glycine dosage from 250 mg/kg b.w. (earlier reports by the same authors) to 100 mg/kg b.w. (present data) is generally compensated by l-proline priming. The IRI serum levels were almost unchanged. By l-proline priming, the glycine test can also be applied to subjects with body weight over 40 kg, in doses of 100 mg/kg b.w. for exploring the secretory reserve of the somatotropic axis.

Amino Acids↗
PubMedDate not supplied

High level of human growth hormone (HGH) in cerebrospinal fluid patients with pituitary tumors.

Six patients with suprasellar extension of pituitary HGH-secreting tumors showed the cerebrospinal fluid (CSF) content in human growth hormone (HGH) to be very high, i.e. 164.3 +/- muU/ml (mean +/- SEM) (range 8.4--413.8 muU/ml) as compared to ten patients with uncomplicated acromegaly whose values were 50-fold lower, i.e. 3.4 +/- 0.5 muU/ml (range 0.6--7.0 muU/ml), and nine patients with suprasellar extension of other pituitary tumors, showing also low levels of HGH in the CSF, i.e. 2.9 +/- 0.8 muU/ml (range 0.6--7.2 muU/ml). A control group of 29 normal patients without pituitary or brain diseases showed extremely low values of HGH in the CSF (1.9 +/- 0.2 muU/ml), one third being below the sensitivity limit of the assay method. Another control group of 70 patients with hypothalamic diabetes insipidus (n = 18), brain traumatisms (n = 10), brain surgery (n = 20), as well as various brain diseases (n = 22), also showed low HGH levels in the CSF, like the normal control group. It is shown that a high level of HGH in the CSF has a potential usefulness in the diagnosis of suprasellar extension of the pituitary mass in acromegaly.

Acromegaly↗