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Biomedical subjects

J Lefebvre

Publications and source records attributed to J Lefebvre.

At least 145 records · Page 8Linked to original sources
PubMed1987

Establishment and characterization of a new cell line (VHB-1) derived from a primary breast carcinoma.

A continuous line of human breast carcinoma cells, VHB-1, was established in culture following collagenase treatment of an infiltrating duct cell carcinoma. The cells displayed an epithelial pattern and multiplied rapidly. Maintained in monolayer culture, the VHB-1 cells exhibited a 30-h doubling time and a plating efficiency of 20%. The cells possessed an abnormal karyotype with a mode of 70-74 chromosomes per cell. The karyotype was heavily rearranged and numerous marker chromosomes were found. Transplantation of the cells into nude mice produced tumors bearing histological resemblance to the original material. The VHB-1 cells contained significant levels of prolactin receptors, were steroid hormone (estrogen, progesterone, androgen, glucocorticoid) receptor positive, and were capable of functional differentiation in vitro. These characteristics make the VHB-1 cell line a suitable model for studying the biological properties of human breast tumors.

Aged↗
PubMed1987

Comparison of two 99mTc(V)-dimercaptosuccinic acid preparations.

99mTc(V)-DMSA labelled either by increasing the pH together with a low concentration of Sn, or by increasing the pH only are compared in vitro and in vivo. The gel chromatographic separation shows that after incubation with blood, all the 99mTc(V)-DMSA preparations are stable and do not bind to the plasma proteins. The behavior in rats as well as in clinical studies does not demonstrate any distinctive characteristics between the different radiomolecules. It seems that the pH of the solution is an important factor which controls the formation of 99mTc(V)-DMSA.

Animals↗
PubMed1987

[Natriuretic factors].

There appears to be two distinct natriuretic factors. One group, suspected since 1951 in overloaded dogs, had a low molecular weight: it belongs great affinity for ouabain, binds to digoxin antibodies and inhibits NA-K ATPase; this group seems heterogeneous in spite of the extraction of an amino glucosteroid-like substance from human urines. These factors are vasoconstrictor; the source is not still well known (hypothalamus ?). The atrial natriuretic factor (ANF) is a peptide about 20 to 25 amino acids and comes from a precursor of 152 amino acids, its synthesis was successful; secreted in the plasma from endocrine atrial granules, it causes striking natriuresis and diuresis and relaxes vascular and intestinal smooth muscle; it acts on guanylate cyclase but its renal mechanism of action is not well known; it constitutes an antagonist axe to ADH and RAA system. The relations between the two groups of natriuretic factors do not seem still very clear.

Animals↗
PubMed1986

Further characterization of the light breast cyst fluid protein, GCDFP-15.

A light protein of breast cyst fluid from women with gross cystic disease, termed GCDFP-15 in the literature, has been investigated. This light protein was purified by preparative electrophoresis on sodium dodecyl sulfate polyacrylamide gel. Its isoelectric point has been determined as 3.75 and its molecular weight has been estimated at 17 400. The light protein was a glycoprotein containing about 163 amino acid residues; the glucidic fraction corresponded to 11% of the molecular weight. The N-terminal amino acid was blocked and the C-terminal amino acid was determined as valine. Antisera raised against this light protein have proved to be specific. In the literature, there is evidence suggesting that apocrine secretion is of prime importance in conditioning the biochemical composition of breast cyst fluid. Further information is needed to substantiate the hypothesis that in gross cystic disease the apocrine epithelium itself or some of its functional aspects are associated with the risk of neoplasia. The physicochemical characterization of the breast cyst fluid protein can contribute to the study of its biosynthesis and provide a better understanding of the physiopathology of gross cystic disease and its relationship to breast carcinoma.

Amino Acids↗
PubMed1986

Clinical and biological phenotypes in late-onset 21-hydroxylase deficiency.

We analyzed data from 20 patients with late-onset 21-hydroxylase deficiency (LOHD). Three clinical phenotypes could be distinguished among the 18 women. Seven (39%) presented with clinical features suggesting polycystic ovarian disease (PCOD). However, despite androgen levels similar to those of patients with typical PCOD, high serum LH to FSH ratios were not consistently found. Seven other women (39%) presented with isolated hirsutism, suggesting idiopathic hirsutism. The remaining 4 women (22%) had no manifestations of androgen excess and were considered to have the cryptic form of LOHD. Serum 17-hydroxyprogesterone (17-OHP) and androgen levels were similar in the 3 phenotypes, suggesting that the clinical expression of LOHD in women is modulated by individual factors, such as androgen sensitivity. The 2 men were detected by family study and were clinically normal. Since clinical diagnosis of LOHD is impossible, we concentrated on hormonal data with the aim of providing guidelines for the biological diagnosis of LOHD. Assay of basal serum 17-OHD at 0800 h in both sexes and in the early follicular phase in women was sufficient to establish the diagnosis of LOHD in most patients. If doubtful results are obtained, i.e. serum 17-OHP levels between 2 and 5 ng/ml, an ACTH test must be performed. Post-ACTH serum 17-OHP levels exceeding 10 ng/ml confirm the diagnosis of LOHD. Such results should avoid confusion with heterozygotes for 21-hydroxylase deficiency, whose frequency is high within the general population and may be even higher in patients with idiopathic hirsutism or PCOD.

17-alpha-Hydroxyprogesterone↗
PubMed1986

Dopamine-secreting pheochromocytoma: an unrecognized entity? Classification of pheochromocytomas according to their type of secretion.

A pheochromocytoma that exclusively secretes dopamine (DA) rather than predominantly DA among a blend of catecholamines is as yet unreported. Of the 50 patients with pheochromocytoma who have undergone surgery, 32 underwent treatment within the last 5 years (when DA assay has been available). One half of these patients (15/32) exhibited DA secretion either in mixed catecholamines (12 patients) or exclusively (three patients). All three patients with exclusive DA-secreting tumors were normotensive. Without hypertension, the clinical investigation was a diagnostic challenge (unexplained cough or flank mass with inflammatory features). All three tumors were malignant and two were ectopic. Five of the 12 patients with mixed catecholamine-secreting tumors whose secretions included DA were hypertensive. Five other patients had flank mass and one had an unexplained cough. Tumors were rather large, and three of the tumors with mixed secretion were ectopic. Of the 12 patients, seven had tumors that were judged to be malignant. Three patients exhibited a dramatic decrease in blood pressure under alpha-blockade, which was not used in subsequent cases. Predominant or exclusive secretion of DA would explain the lack of hypertension due to its antiadrenergic action that inhibits the vasoconstrictive effects of other amines. Hypertension in patients with pheochromocytoma might depend on the ratio of DA/noradrenaline + adrenaline.

Adrenal Gland Neoplasms↗
PubMed1986

[Catecholamines in the cardiovascular expression of pheochromocytoma. II--Study of free urinary catecholamines in 14 pheochromocytomas. Classification of pheochromocytomas according to type of secretion].

Studies were conducted in 14 patients with pheochromocytoma over a 3-year period. Circumstances of detection of these tumors varied greatly and were sometimes misleading, hypertension being an inconstant finding in the clinical history and was not always the predominant feature. Biologic exploration involved assay of excretion of free urinary noradrenaline (NA), adrenaline (AD) and dopamine (DA) using a HPLC technique as well as assay of total methoxy derivatives and urinary vanilmandelic acid. Validity of each assay in the diagnosis of pheochromocytoma could be evaluated and only the total free methoxy derivatives gave false negative results. Hormonal secretion of pheochromocytoma is often mixed, but sometimes predominant or exclusive for a single catecholamine. Relative increases of the different catecholamines, evaluated from the ratios DA/NA and DA/NA + AD, are an important factor since a relation exists between blood pressure induced symptomatology and equilibrium between hypotensive hormone (DA) and pressor amines (NA + AD); 3 types of pheochromocytoma can be described: NA-induced with paroxysmal or permanent hypertension but without typical metabolic and cardiac disorders, and with a very reduced DA/NA + AD ratio during hypertensive crises; AD-induced without permanent hypertension but with a mainly orthostatic hypotension and episodes of cardiovascular collapse following hypertensive attacks and with an AD/NA ratio greater than 1; finally the DA-induced lesion in which hypertension is never associated and manifestations are misleading and atypical with an elevated DA/NA + AD ratio.

Adrenal Gland Neoplasms↗
PubMed1985

Transferrin receptors in cultured breast cancer cells.

Transferrin receptors were demonstrated on the cell membrane of breast cancer epithelial cells in primary or long-term culture. Diferric transferrin binding was saturable, specific and was not related to DNA content or clinical and histological features of the tumour. However a good correlation (p less than 0.01) was found between transferrin binding and thymidine incorporation. These results suggest the possibility of transferrin receptor measurement as a reflection of the proliferative activity of cultured breast tumour cells.

Breast Neoplasms↗
PubMed1985

Catecholestrogen binding sites in breast cancer.

The binding of 2-hydroxyestrone (2OH E1), a catecholestrogen which is the main end product of the 2-hydroxylation of estrogen, was investigated in breast cancers. 2OH E1-specific bindings were found in the cytosol (Kd = 0.54 +/- 0.10 nM) and in the endoplasmic reticulum (Kd = 3.36 +/- 1.32 nM). The dissociation rate constants of complexes between [3H]2OH E1 and cytosol or membrane binding sites were 3.30 h-1 and 8.30 h-1 respectively. Qualitative analysis of [3H]2OH E1 cytosolic complexes demonstrated a specific binding component with a mol. wt of 330,000 Daltons. Specificity experiments showed that nonestrogenic hormones were unable to compete with 2OH E1 for its binding sites, whereas triphenylethylene derivatives and catecholamines were potent 2OH E1 competitors. The presence of 2OH E1 specific bindings suggests a potential role of catecholestrogen in breast cancer.

Binding Sites↗
PubMed1984

[Blood and plasma hyperviscosity in primary hyperlipidemia].

Plasma and blood viscosities were studied in 15 hyperlipidemic (HLP) patients and in 10 healthy volunteers. Viscosities were measured at 25 degrees C using a couette type viscosimeter. Plasma and blood viscosities were significantly increased in HLP patients. This increase in viscosity was better correlated with triglyceride than with cholesterol level. This result might partially account for the clinical differences observed between hypertriglyceridemia and hypercholesterolemia.

Blood Viscosity↗
PubMed1984

Changes in steroid concentrations in follicular fluid and sexual behavior during pseudopregnancy in the rabbit.

Changes in sexual behavior and progesterone, oestrone, oestradiol, testosterone and androstenedione concentrations have been studied in the follicular fluid of 25 pseudopregnant rabbits on Days 6, 9, 12, 15 and 18. The sexual behavior score seemed to rise at the end of pseudopregnancy and follicular steroid levels were higher on Days 6 and 18 of pseudopregnancy than on Days 9, 12 or 15. The generalized distance D2 of Mahalanobis showed the existence of four periods during pseudopregnancy: Day 6, Days 9 and 12 which were similar, Day 15 and Day 18. These stages were found to differ by a compound of the sexual behavior score and the concentrations of androgens and oestradiol in follicular fluid. There was no relationship between sexual behavior and follicular steroid concentrations. Nevertheless, undetectable levels of oestradiol in the follicular fluid were only observed in deeply dioestrus females.

Androstenedione↗
PubMed1984

[EGF receptors in human breast cancer. Relation to hormonal receptors].

EGF membrane receptors (R-EGF) were assayed in 65 human breast cancer biopsies. The Scatchard analysis of the binding of 125I-EGF indicated a single class of sites with an apparent dissociation constant of 1 nM. Fourty-eight percent of the tumors are R-EGF positive (specific binding greater than 1% of total radioactivity), the level of receptors reaching 14%. We have not observed any relationship between R-EGF and hormone receptors (estradiol, progesterone and prolactin) or clinical and histological characteristics of the tumor. Taking into account the role of EGF in growth of some human breast cancer epithelial cells culture and the possible production of R-EGF by oncogenes, these results suggest that R-EGF could be an uindependent biochemical marker of human breast cancer.

Breast Neoplasms↗