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M Chambon

Publications and source records attributed to M Chambon.

At least 55 records · Page 3Linked to original sources
PubMed1987

[Lipid pneumonia and superinfection by Mycobacterium fortuitum. Apropos of a case].

We report a case of lipoid pneumonia complicated by supra-infection with Mycobacterium fortuitum. The diagnosis of a lipoid pneumonia was suggested by the CT Scanner which showed a negative density in the pneumonic tissue. The supra-infection by the mycobacterium dit not change the radiological opacities which stayed the same following a cure of the mycobacterial infection. A histo-pathological study showed evidence of macrophages with voluminous lipid inclusions but equally the atypical mycobacteria were associated with a giant cell-epithelioid reaction. In patients with a lipoid pneumonia the possibility of an infection should be considered and a supra-infection with an atypical mycobacterium should be looked for. At the same time, when a bacteriological study of sputum or fibreoptic aspiration of a rapidly growing mycobacterium is obtained this should raise the possibility of oil inhalations. Alveolar lavage seems to be a technique which seems to be entirely appropriate to obtain the diagnosis of the two concomitant disorders.

Amikacin↗
PubMed1986

Autocrine growth stimulation of the MCF 7 breast cancer cells by the estrogen-regulated 52 K protein.

The growth of MCF 7 human breast cancer cells is stimulated in vitro by estradiol (E2) and we have previously shown that estrogen-regulated glycoproteins released into the culture medium can partly mimic this effect. In this paper, we evaluate the mitogenic activity of the 52 K glycoprotein, which is a major E2-stimulated protein released by MCF 7 cells. The 52 K protein was purified 600-fold by affinity chromatography on Concanavalin A and an anti-52 K monoclonal antibody Sepharose columns. The 99% purified 52 K protein fraction stimulated the growth of estrogen-deprived MCF 7 cells. A mean 1.7-fold increase was obtained with nanomolar concentrations of seven different preparations of 52 K protein. This stimulation represented 40% of the mitogenic effect of E2. Both the 52 K protein and E2 induced microvilli at the cell surface but the effect of the 52 K protein occurred earlier. Other putative growth factors which are also stimulated by E2 and observed by [35S]cysteine labeling did not comigrate with the purified 52 K protein. Finally, the labeled 52 K protein was found to enter MCF 7 cells and to be processed into an immunoreactive 34 K protein. These data indicate that the E2-regulated 52 K glycoprotein is an autocrine mitogen on MCF 7 cells in culture and support the hypothesis that estrogens stimulate the growth of mammary cancer via this (and possibly other) secreted protein(s) acting as autocrine (and paracrine?) growth factors.

Antibodies, Monoclonal↗
PubMed1985

[Evaluation of 4 years of surveillance of enteroviruses in sewage. Correlation with human pathology].

This survey is concerned with isolations of enteroviruses from sewage and stools of children admitted to pediatric wards of the Clermont-Ferrand hospital during 4 years (from january 1, 1980, to december 31, 1983). Some epidemics of different serotypes (Coxsackies B1, B4, B5, Echovirus 33) occurred, mainly between june and october. In some instances, virus isolation in sewage occurred a few weeks before epidemic of the same virus, giving some predictive value to pediatric pathology. This survey allowed us to adapt immunologic diagnosis of enteroviruses in children and limit the use of expensive reagents.

Child↗
PubMed1984

Effect of estradiol on nonmalignant human mammary cells in primary culture.

We have studied effects of estradiol on primary cultures of nonmalignant human mammary tissue collected surgically from fibroadenomas or during reduction mammoplasties. After enzymatic digestion, "organoids" made of epithelial cells organized in ductal or alveolar structure were grown in primary cultures (up to 12 days) on different substrata (glass, plastic, collagen-coated plastic, and floating collagen membranes). Transmission and scanning electron microscopy showed that these organoids were responsive to physiological concentrations of estradiol. Condensed chromatin of epithelial cells became dispersed following estrogen treatment. The plasma membrane of epithelial cells at the surface of the organoids was dramatically modified by estradiol, which increased the number and the length of the microvilli, as observed previously in the MCF7 breast cancer cell line (Vic et al., Cancer Res., 42: 667-673, 1982). This effect was not observed with the same concentrations of progesterone, dexamethasone, dihydrotestosterone, or 1 microM tamoxifen or in fibroblasts of the same tissue, demonstrating that epithelial mammary cells are specifically responsive to estradiol. By contrast, no effect of estradiol could be evidenced on the [35S]methionine-labeled proteins released into the medium by the organoids. The estrogen-regulated protein of Mr 52,000 was not found in the medium after purification by concanavalin A-sepharose or immunoprecipitation with specific antibodies to the Mr 52,000 protein from MCF7 cells. We conclude that nonmalignant mammary cells are responsive to estrogens in primary culture.

Adenofibroma↗
PubMed1983

[Estrogen-induced proteins secreted by MCF7 human breast cancer cells stimulate their proliferation].

In the MCF7 human breast cancer cells, estrogens stimulate in vitro cell proliferation and biosynthesis of specific proteins which are released into the culture medium; the most abundant of these is a 52,000 dalton glycoprotein. Conditioned media from E2-treated MCF7 cells stimulate the growth of E2-deprived MCF7 cells, whereas conditioned media from untreated control cells are ineffective. At protein concentration greater than 5 micrograms/ml, an inhibitory effect was also obtained with control media. The mitogenic factors of these conditioned media are non-dialysable, sensitive to temperature and proteases and adsorbed on Con A Sepharose. The cell surface of MCF7 cells, examined by scanning electron microscopy, is differentially affected by these two types of conditioned media. We conclude that estrogens may stimulate the growth of breast cancer cells indirectly via the induction of glycoproteins acting as growth factors.

Breast Neoplasms↗
PubMed1983

Scanning electron-microscopical study of epididymal secretions in the lizard Lacerta vivipara (Reptilia, Squamata) and of their relationships with spermatozoa.

During the breeding season (April, May) the epididymis of the lizard Lacerta vivipara produces voluminous secretory granules which are abundantly discharged into the lumen of the duct where they mingle with spermatozoa. The mode of secretion appears quite unusual with respect to the method by which the cells discharge their products, the granules coming out of the cells like bullets out of a gun barrel. Spermatozoa come into close relationships with discharged granules, dipping into their outer layers. This is probably the way in which the heads of spermatozoa become covered with the epididymal soluble protein (protein L). This mode of secretion in Lacerta is discussed with regard to possible artifacts and compared with that encountered in the epididymis of some other species including mammals.

Animals↗
PubMed1983

Effects of bromocriptine on pituitary-testicular function in the rat: possible inhibition of in vitro production of androgen by Leydig cells.

The effect of bromocriptine (BR) on pituitary-testicular function has been investigated in vivo and in vitro in adult male rats. Testosterone production in vitro by collagenase- dispersed Leydig cells from 84-day-old rats was evaluated in the presence and absence of hCG and/or different doses of BR. In the presence of 1.5 X 10(-5) M BR, both basal and hCG-stimulated testosterone production were decreased whereas at lower doses BR was ineffective. In vivo 60-day-old rats were injected sc with BR (150 micrograms/rat or 750 micrograms/rat twice daily) or vehicle for 24 days. This treatment reduced the plasma level and pituitary content of prolactin, slightly increased the plasma levels of LH and FSH but did not affect pituitary gonadotrophin content. Irrespective of the dose of BR injected, plasma levels of androgen did not change, but with the large dose of BR a decrease in testicular content of testosterone (P = 0.05) was observed. In the same animals the number of LH/hCG receptors was significantly reduced, and the sensitivity of the isolated Leydig cells to hCG stimulation in vitro was reduced; however, both the basal secretion and the maximum testosterone response to hCG were unaffected. These results show impairment of pituitary-testicular function in BR-treated rats, either as a result of BR-induced hypoprolactinaemia or as a consequence of direct effects of BR on the Leydig cells.

Androgens↗
PubMed1982

Long-term observation of cardiac rhythm and automaticity in the dog after excision of the sinoatrial node.

Twenty-nine dogs having undergone aseptic excision of the sinoatrial node were kept under observation, in most cases, for more than a year. Observation confirmed the instability of the new rhythm or rhythms taking over the automaticity after excision of the physiological pacemaker. This instability was particularly marked during the first ten days following surgery. The new pacemaking sites were mainly junctional. Spontaneous pauses occurred. Later on, in more than 50% of the cases, pacemaker sites became localized in the high zone of the atrium, and the rhythm was of sinus node origin. Through the evolution, rhythm disorders were observed as sequences of bradycardia, tachycardia, atrial fibrillation, and flutter. Unexcised nodal cells were found in three animals, through their presence did not make any significant difference to their ECGs as compared with animals in which removal of nodal cells was complete. Surgical implantation of electrodes enabled a study to be made of recovery time, which was always well within physiological limits, but was particularly long during the ten days following surgery. The values varied greatly from one examination to another. Propranolol (0.5 mg/kg i.v.) aggravated the disorders and lengthened corrected recovery time; atropine had varying effects. An analogy is apparent between the disorders described here and those observed in man in the sick sinus syndrome.

Animals↗
PubMed1980

[Plasma testosterone level and structure of the epididymis and accessory organs of the boar (Sus scrofa L.) after hypophysectomy followed by hCG gonadotropin administration].

Hypophysectomy of the boar resulted in a rapid drop in plasma testosterone level. hCG injections (400 IU/day) considerably elevated testosteronemia (up to 16.41 ng/ml). This effect was obtained either in the days following the operation or several months after (up to 134 days). In the latter case, the effect was temporary because the testosterone level dropped again after 15 days of injections. The sexual target organs (epididymis, seminal vesicle, prostate and Cowper glands) underwent structural change which, in the epithelium, corresponded to fluctuations in testosterone level. These effects were less marked in the cauda epididymis than in other target tissues. In various target organs, the conjunctivomuscular stroma developed after the operation; it did not regress at all, or incompletely, when the epithelia were stimulated indirectly by hCG, and began to hypertrophy when the hCG was no longer effective. Variations in stromal reaction were organ-dependent. When the hCG was administered for more than 14 days, it seemed to have a desensitizing effect; these mechanisms have been discussed.

Animals↗
PubMed1978

[Histoautoradiographic study of two target organs (epididymis and femoral glands) after injection of 3H testosterone in a non-mammalian vertebrae, the viviparous lizard].

After 3H testosterone injection into castrated males of the Lizard Lacerta vivipara, the radioactive compound is detected by radioautography of epididymis, femoral glands, gut and liver. Between 1 hr. 30 min. to 12 hrs. of retention the 3H material concentrates progressively into nuclei of the glandular cells of epididymis and femoral organs although no particular concentration occurs in gut and liver cells. This submammalian model is consistent with those previously described for mammals.

Animals↗
PubMed1978

[Histo-autoradiographic study of a testosterone target organ, the epididymis of the lizard (Lacerta vivipara), after administration of 3H-17 beta-estradiol].

[6,7 3H] oestradiol-17 beta was injected into castrated male viviparous lizards in order to compare retention of this steroid to that of testosterone during the period of sexual activity. Retention of the isotope in epididymis was greater than in blood, lung and stomach. Radioautographs of epididymis indicated that oestradiol or a metabolite was concentrated in cell nuclei and over discharged secretory granules as was observed with testosterone. Reason of such binding is not yet known.

Animals↗
PubMed1975

[Mitochondrial reorganization after HCG stimulation of Leydig cells from hypophysectomized hogs].

One to three months after hypophysectomy, porcine Leydig cells contain numerous dense bodies surrounded by a single membrane and crowded with dense rods geometrically arranged. In organotypic culture with HCG they undergo a striking evolution which leads first to intermediate bodies looking like peroxysomes and then to mitochondrial structures. This evolution is quantitatively reduced in a medium without HCG.

Animals↗
PubMedDate not supplied

Sequential rotavirus infections: characterization of serotypes and electrophoretypes.

Few studies have characterized the rotaviruses observed in repeated infections in the same patient. Rotavirus serotypes and electrophoretypes were determined from faecal samples of 24 children hospitalized between 1984 and 1989 in a Clermont-Ferrand hospital and who had had repeated rotavirus shedding. The patients were aged between 3 days and 4 years. Fifty infections were recorded. Of the 48 serotypes obtained, 18 were serotype 1 (37.5%), 10 serotype 2 (20.8%) and 20 serotype 4 (41.7%). Serotype 3 was not found. Seven serotype 2 infections were characterized during rehospitalization. Six patients had two subsequent infections with the same serotype.

Child, Preschool↗