PubMed Health⌕ Search

Biomedical subjects

F O Ranelletti

Publications and source records attributed to F O Ranelletti.

107 records · Page 6Linked to original sources
PubMed1981

Glucocorticoid receptors and in vitro corticosensitivity of peanut-positive and peanut-negative human thymocyte subpopulations.

In 6 human thymus glands, the immature subset of thymocytes was separated from the more mature one, by differential peanut lectin agglutination. These 2 cell subpopulations were analyzed for glucocorticoid receptor content by using a whole cell assay, with (3H)-triamcinolone acetonide as tracer. The unagglutinated thymocytes (peanut negative) contained about 2 times more receptor sites per cell than agglutinated (peanut positive) ones (7650 +/- 1550 S.D. verus 3195 +/- 896 S.D.). The affinity for steroid was similar in both cell subsets, as was the stereospecificity for glucocorticoids, the time-course of steroid-receptor association, and cytoplasmic to nuclear translocation. Despite the greater number of glucocorticoid receptor sites, the peanut-negative thymocyte subpopulation did not differ from the peanut-positive one in its sensitivity to the inhibitory effects of triamcinolone acetonide, as determined by measurements of the incorporation of radiolabeled precursors of protein and DNA. Moreover, the peanut-negative subset appeared more resistant in vitro to the steroid-induced cell lysis as compared to the peanut-positive one. Thus, our data suggest that glucocorticoid receptor density and corticosensitivity are not directly correlated and that the number of glucocorticoid receptor sites may be dependent on the degree of immunologic maturation.

Binding Sites↗
PubMed1981

Glucocorticoid receptor determinations in leukemia patients using cytosol and whole-cell assays.

Parallel determinations of glucocorticoid receptors in the cells of patients with various forms of leukemia were made by two assay methods, one using cell-free cytosolic extracts and the other using whole-cell preparations. Both assays revealed saturable binding of triamcinolone acetonide in all cases. The mean equilibrium dissociation constant for the interaction of triamcinolone acetonide with the cytoplasmic receptor at 2 degrees was 9.45 +/- 6.33 (S.D.) nM while that for the whole-cell binding at 37 degrees was 6.13 +/- 3.25 nM, suggesting an increase in receptor affinity at physiological temperatures. Competition experiments with various unlabeled steroids revealed a higher degree of glucocorticoid specificity at 37 degrees in whole-cell suspensions than at 2 degrees in cytosol. In a comparative analysis of 41 leukemic cell specimens, it was found that determinations carried out by whole-cell assay, calculated as number of sites per cell correlated well with those performed by cytosol assay, calculated as fmol/mg protein, independent of the type of leukemia. However, for cells with low receptor content, the two assay methods were more difficult to compare. In agreement with previous reports, the cytosol assay consistently underestimated the number of receptors with respect to the whole-cell assay, particularly in cases of lymphatic leukemia. Furthermore, the underestimation decreased for increasing levels of total cellular receptor. These results suggest that, in addition to possible defects in the cytoplasm-to-nucleus translocation process, the acceptor-binding capacity of the nucleus may also represent one of the factors which determines the levels of assayable cytoplasmic receptors. Moreover, they indicate that the two assay methods furnish nonequivalent information.

Cytosol↗
PubMed1980

Clinical implications of glucocorticoid receptor studies in childhood acute lymphoblastic leukemia.

We have performed in parallel, in 19 children with acute lymphoblastic leukemia, a quantitative determination of glucocorticoid levels, in vitro steroid induced inhibition of nucleic acid precursors, and a short-term clinical trial of corticosteroids alone, before the treatment was given, which included corticosteroids and other drugs. From our results it appears that high glucocorticoid receptor levels in acute lymphoblastic leukemia of children do not guarantee a clinical response to corticosteroids. On the other hand, glucocorticoid receptors may turn out to be of value in predicting a poor response to corticosteroids only if their levels are considerably low.

Adolescent↗
PubMed1978

Glucocorticoid-binding components in human thymus hyperplasia.

Preliminary experiments on thymocyte suspensions derived from human thymus hyperplasia indicated the presence of specific cytoplasmic receptors binding [3H]-dexamethasone with high affinity and specificity. The receptor was rapidly transferred into the nuclei at 28 degrees but not at 2 degrees. With cell-free preparations and ion-exchange cellulose-impregnated paper filters, thymus cytosol bound [3H]dexamethasone with a dissociation constant of 4.3 x 10(-9) M; the concentration of receptor sites was 9.6 x 10(-14) mole/mg cytosol protein. Cytosol contained binding components that sedimented at approximately 7S and 3.6S (low ionic strength) and at 4S (high ionic strength). Competition studies showed high specificity for glucocorticoids since binding of labeled dexamethasone was inhibited in the presence of 10(-6) M beta-methasone, prednisolone acetate, dexamethasone, corticosterone, cortisol, and cortisone. 17beta-Estradiol, testosterone, and dihydrotestosterone at 10(-6) M did not inhibit specific binding of [3H]dexamethasone. Thus, the dexamethasone-binding components of the human thymus hyperplasia had properties similar to those described for steroid hormone receptors present in target tissues.

Cell Nucleus↗
PubMedDate not supplied

Effects of long-term cadmium exposure on the testis of rabbits: ultrastructural study.

Six male rabbits received for 9 months drinking water containing 20 micrograms/ml of cadmium (Cd). At the end of the treatment, the Cd contents of kidney and testis were 175 +/- 34 and 0.8 +/- 0.2 micrograms/g wet weight, respectively. Ultrastructural examination by transmission electron microscopy (EM) showed that, in the Sertoli cells, the size of the lysosomes was increased; spermatogenetic cells, vessels and Leydig cells showed no significant alterations. Observations with both transmission and scanning EM did not evidence changes in the blood-testis barrier, but our results do not exclude that male fertility may be affected by chronic exposure to cadmium.

Animals↗
PubMedDate not supplied

Type II estrogen binding sites (EBS) in intracranial tumors.

Four meningiomas and six neuroepithelial tumors were assayed for the presence of estrogen receptors (ER), type II estrogen binding sites (EBS) and progesterone receptors (PgR). ER were detected in 7 out of 10 cases with levels ranging between 2.5 and 20.7 fmoles/mg of cytosolic protein. On the contrary, PgR were found in all samples (10 cases) and their levels ranged between 8.8 and 130.6 fmoles/mg of cytosolic protein. All tumor samples expressed appreciable amounts of type II EBS ranging between 452 and 2320 fmoles/mg of protein. Although the precise functional role of type II EBS is still unknown, their presence may reflect an hormonal sensitivity of these tumors.

Brain Neoplasms↗
PubMedDate not supplied

Morphological changes induced by epidermal growth factor and estradiol on CG5 human breast cancer cell line: a scanning electron microscopy study.

We studied the morphological changes induced by 17-b-estradiol (E2) and/or Epidermal Growth Factor (EGF) in an estrogen sensitive human breast cancer cell line (CG5) characterized by a high growth responsiveness to EGF and by a single class of high affinity I-125 EGF binding sites. EGF treated cultures showed conspicuous morphological changes consisting of retraction from the substrate, loss of cell-to-cell contacts and expression of surface crest-like and bled protrusions. E2-treated cells showed an increased number of microvilli with respect to control. In cells simultaneously treated with EGF and E2, despite the expression of microvilli, cell surface modifications were similar to those found in the presence of EGF alone, suggesting that EGF may negatively modulate the estrogen-induced morphological changes. In CG5 cells EGF induced a reduction of ER and PR levels and inhibited the estrogen-induced increase of PR. Our findings suggest that the activation of specific EGF-induced intracellular pathways could decrease or modulate those induced by E2.

Breast Neoplasms↗
PubMedDate not supplied

Some differences in steroid receptors between meningeal and neuroepithelial tumors.

In our study we evaluated the presence of steroid hormone receptors in a large series of endocranial tumors and investigated the possible correlations between receptor presence and levels and patient's age and sex. Our data indicate that steroid receptor behavior in the neoplasias considered is quite different from that observed in endocrine-related tumors, such as breast and endometrial cancer. Moreover, in neuroepithelial tumors an interesting difference between male and female subjects has been found regarding the receptor distribution in poor differentiated neoplasias.

Adolescent↗
PubMedDate not supplied

Polydioxanone in anastomosis of rabbit tubes. A morphological study of the epithelium.

Eight NZW rabbits were submitted to end-to-end tubal anastomosis using polydioxanone (PDS), (Ethicon). The animals were sacrificed at two-week intervals between the second and sixteenth week after operating. The tubes were removed and analysed with the scanning electron microscope for the purpose of studying the morphology of the epithelium. Ciliogenesis was completed between the second and fourth weeks. After this period the epithelial conditions observed were completely normal, except for an abundant mucous secretion which, however, was totally normal after sixteen weeks.

Animals↗