Magnetic resonance imaging in antenatal diagnosis of tuberous sclerosis.
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Humans↗
Biomedical subjects
V Mirlesse
Publications and source records attributed to V Mirlesse.
Parathyroid hormone increases epidermal growth factor receptors in cultured human trophoblastic cells from early and term placenta.
The effect of PTH on the epidermal growth factor (EGF) receptor was analyzed during the in vitro differentiation of human cytotrophoblasts. The cytotrophoblasts were isolated by a trypsin-DNase method from first trimester and term placentas and purified on a Percoll gradient. In culture, these cells aggregated and fused together to form a syncytium. This in vitro differentiation was associated with a 2-fold increase in 125I-EGF binding after 48 h of culture. The addition of 0.1 microM PTH (PTH-treated cells) to the culture medium induced a significant 2- to 3-fold increase (P less than 0.005) in EGF binding. The effect was dose related with a maximum obtained at a 1 nM concentration. Scatchard analyses revealed that PTH-treated cells possess a 2-fold higher number of high affinity sites as compared to control cells from early placenta (0.71 +/- 0.06 pmol/mg protein and 0.34 +/- 0.04 pmol/mg protein, respectively) and from term placenta (1.24 +/- 0.10 pmol/mg protein and 0.61 +/- 0.07 pmol/mg protein, respectively). The apparent Kd values for high affinity sites (0.15 nM) and for low affinity sites (4 nM) were not altered either by the gestational age of the cells or by PTH treatment. With respect to the EGF-dependent phosphorylation in membranes of trophoblast cells in culture, it was found that the phosphorylation of two major proteins of 175 kilodaltons and 35 kilodaltons, is greatly increased in PTH-treated cell membranes in the presence of EGF. This PTH-induced effect on EGF receptors was associated with an augmented functional response of trophoblastic cells to EGF. PTH increased the EGF-stimulated secretion of hCG. These results demonstrate that PTH increases the number of biologically active EGF receptors during the in vitro differentiation of human trophoblast cells. This PTH-induced effect suggests a role for this hormone in the regulation of the growth and the endocrine functions of these cells.
Cells, Cultured↗
Regulation of growth hormone secretion in human trophoblastic cells in culture.
In this study, we have cultured in vitro purified trophoblastic cells from first-trimester and term human placenta. These cells were obtained by specific enzymatic digestion and centrifugation through a Percoll gradient. Using 2 specific monoclonal antibodies, the pituitary 22-kD growth hormone (GH) and the placental GH variant were assayed in the culture medium by radioimmunoassay. After 48 h of culture, only the placental GH variant was measured in the medium corresponding to first-trimester placenta (3.4 ng/24 h/10(5) cells). Surprisingly, an immunoactivity pattern of pituitary GH type was found in 3 out of 5 media conditioned with term placenta cells, while GH immunoactivity was very low, around the detection level, in the 2 others. These secretions are not modified with the time in culture and the state of differentiation of the cells from cytotrophoblast to syncytiotrophoblast. Neither in early nor in term placenta does the addition of GH-releasing factor (10(-6) M in the culture medium) stimulate the secretion of pituitary 22-kD GH or placental GH variant.
Cells, Cultured↗
Epidermal growth factor receptors in cultured human trophoblast cells from first- and third-trimester placentas.
Epidermal growth factor (EGF) receptors were studied during the in vitro differentiation of human trophoblast cells from first- and third-trimester placentas. Cytotrophoblasts were isolated by enzymatic digestion and purified on a discontinuous Percoll gradient. As analyzed by flow cytometry, 5% of the cells are in the G2M phase in the early placenta and 0% in the term placenta. In culture, the cytotrophoblasts at both gestational ages flatten out, aggregate, and fuse together to form syncytiotrophoblasts. This in vitro morphological differentiation is associated with a threefold increase in the ability to bind specifically 125I-EGF. Trophoblastic cells from the term placenta have a significantly (p less than 0.005) higher receptor number (68.6 +/- 9.5 fmol/mg protein) for EGF after 2 days of culture than first-trimester cytotrophoblasts (35.8 +/- 2.3 fmol/mg protein). Scatchard plot analysis revealed two classes of binding sites with a similar affinity in both first-trimester and term placentas (9.5 x 10(9) M-1 for the high-affinity, 0.5 x 10(9) M-1 for the low affinity site). When 125I-EGF was affinity cross-linked to cytotrophoblasts, the receptors appeared as a specific band with a molecular weight of 180 kD in SDS-PAGE. This study demonstrates that the culture of cytotrophoblasts offer an appropriate model to study the modulation of EGF receptors.
Cell Differentiation↗
[The value of preoperative location of microcalcifications without palpable breast tumors].
In 1986 and 1987, 224 patients were operated on for microcalcification without palpable lesions of the breast. Classical orthogonal (perpendicular grid) localisation was performed in 123 patients: external cutaneous localisation of the nipple was performed in 78 patients and hook localisation in 25 patients. Primary excision without the need for re-excision was possible respectively in 88% and 94% with external and hook localisation and in 83% after orthogonal localisation. The mean volume of the operation specimen was lower after hook (38.3 cm3) than after cutaneous or orthogonal localisation (54.6 cm3). 43% of the patients had a malignant lesion and even when the cluster of microcalcifications was single 50% of the margins were positive. Pre-operative localisation of occult breast lesions has simplified the surgical technique of excision. Nevertheless the pre-operative diagnosis of malignancy should be improved on in order to perform a procedure both diagnostic and therapeutic in the same operation.
Breast Diseases↗