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Biomedical subjects

A Danguy

Publications and source records attributed to A Danguy.

100 records · Page 6Linked to original sources
PubMedDate not supplied

Hormonal regulation of uterine epithelial cell proliferation. I. Effects of estradiol or progesterone administered separately.

Using an in vivo tritiated thymidine (3H-TdR) labeling followed by autoradiography, the effects at different times before sacrifice of single or paired injections of 17-beta-estradiol (E2) or progesterone (Pg) at various concentrations were investigated in adult B6D2FI ovariectomized mouse luminal and glandular uterine epithelium. With regard to the luminal epithelium, E2 (0.25, 2.50 or 25.00 micrograms/animal) exerts a mitogenic influence which is dose-related. Pg (125, 600 or 5000 micrograms/animal) exerts a significant proliferative effect only at a high dose. With regard to glandular epithelium, E2 and Pg have an almost identical mitogenic influence which is dose-related. A two-step Pg administration (2 x 125 micrograms) inhibits cell proliferation in glandular epithelium as compared to the promoting action exerted by a single injection. No refractory response was observed after a two-step E2 administration in either the luminal or the glandular epithelium. These data demonstrate that cell proliferation in the uterine luminal epithelium of an adult B6D2F1 mouse is very sensitive to E2 but not to Pg, whereas these two steroids have a similar mitogenic influence on the cell proliferation of the glandular epithelium. Moreover, a second Pg administration seems to have an inhibiting effect on cell proliferation as compared to that exerted by the first injection performed 12 or 24 hours earlier. In contrast, the repetition of E2 treatment would seem to exert an additive effect on uterine epithelial cell proliferation. In conclusion, epithelial components of the endometrium are complex steroid targets. The two major cell types (luminal, glandular) differ in their abilities to respond to steroid stimulation by entering into DNA synthesis.

Animals↗
PubMedDate not supplied

Hormonal regulation of uterine epithelial cell proliferation. II. Effects of estradiol and progesterone administered in combination.

The effects of estradiol (E2) and progesterone (Pg) administered in combination on the cell proliferation of the ovariectomized B6D2F1 mouse uterine epithelium were assessed by thymidine autoradiography. In the luminal and glandular cell populations Pg inhibits the mitogenic effect of E2 when administered simultaneously or 24 hours after E2; when Pg is given 12 hours after E2 it does not block but slows down the proliferative effect of E2, at least at the concentrations studied here. Given prior to E2, Pg rather exerts an additive (synergistic) effect on uterine epithelia. It is concluded that Pg can exert different actions on the E2- mitogenic effect induced at both luminal and glandular levels. Further investigations are needed to understand better the precise biochemical mechanisms involved in the modulating actions of these steroids on the mouse endometrium epithelial cells.

Animals↗
PubMedDate not supplied

Binding of fluorescein isothiocyanate conjugated lectins to MXT mouse mammary neoplasm and their relation to steroid receptor status.

As previous studies have suggested a hormone dependence of binding sites for peanut agglutinin in mammary neoplasm, this feature has been thought to be correlated to steroid receptor status. The present investigation was undertaken on a well-established ovarian-dependent cancer model in order to check this hypothesis. Sections of primitive tumor transplants as well as of tumors induced in vivo by injection of cell clones were analyzed with the use of three fluorescent lectins. The lectin binding sites were evaluated semi-quantitatively and compared with estrogen and progesterone receptor levels. Using non-parametric statistical tests, the results revealed a strong correlation between the expression of peanut agglutinin (PNA) binding sites and steroid receptor status, but only in primitive tumor transplants. No such correlation was observed in tumors induced in vivo, by injection of cell clones. No correlation between the steroid receptor status and the two other lectins (Concanavalin A and Dolichos biflorus) was observed. These data suggest that PNA can be used as a valuable histochemical tool in steroid hormone dependence study.

Animals↗
PubMedDate not supplied

Phenotypic change of the transplantable MXT mammary adenocarcinoma into mixed bone producing sarcoma-like tumors.

The B6D2F1 mouse mammary adenocarcinoma was adapted to grow in vitro as monolayer. After in vitro passaging of tumor cells, phenotypic changes occurred that were expressed in vivo. Following intraperitoneal inoculation of tumor cells, bone-forming tumors developed. These tumors consisted of undifferentiated adenocarcinoma mixed with large amount of cartilagenous and osseous tissue. The etiology of these phenotypic changes was not yet determined. However, hypothesis of the possible origin of the cartilage and bone forming tissue was formulated. The biologic characterization of the intraperitoneally bone-forming tumor was achieved and the experimental conditions to preserve and induce the reproducible sarcoma-like bone forming tumors were defined. Our data support the usefulness of this new original model for fundamental research as well as for screening of anticancer drugs.

Adenocarcinoma↗
PubMedDate not supplied

Effect of estradiol on proliferation and on cell loss in the MXT mouse mammary tumor.

The MXT tumor is an experimental mammary tumor, maintained by transplantation in B6D2F1 mice, which contains significant amounts of estrogen and progesterone receptors. The aim of the present work was to study the effect of estradiol (E2) administration on the cell kinetic parameters (thymidine labeling index: TLI, S phase duration: TS, cell cycle duration: Tc, growth fraction: GF, potential doubling time: T, cell loss factor: luminal diameter) of an MXT anaplastic carcinoma strain. These parameters were analyzed using single-, double- or repetitive-tritiated thymidine (3H-TdR) labeling techniques. Uteri were used as controls for the methodology. Our data clearly demonstrate that E2 exerted a marked stimulatory effect on the tumor cell proliferation. This effect is the net result of a shortening of the mean cell cycle duration (Tc) and of a 3-fold increase of the number of cells produced per time unit in 89% of the total cancer cell population. Beside this stimulatory effect, E2 produces a marked increase of the tumoral cell loss. This loss seems to affect a cell fraction which has reached the quiescent state (Q) for a short time.

Animals↗
PubMedDate not supplied

Influence of inoculation sites and tumor cell culture techniques on the phenotype of a mixed cartilage- and bone-producing mouse mammary tumor.

We have previously reported the characterization of an intraperitoneally (IP) transplantable bone-forming MXT tumor. However, the question was unresolved as whether the bone-forming cells originated from either the host animal or from the neoplasm itself. The present work attempts to answer this question by studying the influences of inoculation sites (subcutaneously, SC; intraperitoneally, IP; in the brain, IB; intracranially, ICR) on both the cartilage- and bone-forming tumor phenotypes. Furthermore the influence of cell culture procedures (two- and three- dimensional cultures) on these phenotypes was investigated. SC administered MXT cancer cells never produce bone-forming tumors, suggesting the existence in the dermis of substance(s) inhibitory to the formation of cartilage or bone. On the contrary, our data clearly demonstrate that bone-forming tumors can be obtained by either IP route, in a way which mimics endochondral ossification, or in the brain (IB), a region usually devoid of connective tissue. This observation substantiates the hypothesis according to which the tumor itself is able to produce osseous tissue. Another main finding is the increasing occurrence of skeletal tissues produced by cells proceeding from three-dimensional culture. Finally, ICR and IB tumors exerted a bone-lytic action against the host skull suggesting that tumor cells either produce osteolytic substances (prostaglandins, enzymes) and/or that they contain various cell types exhibiting different properties toward osteogenesis. This model offers new perspectives for studying the mechanisms of both normal and pathologic osteogenesis.

Animals↗
PubMedDate not supplied

Effects of castration and thyroidectomy on expression of lectin-binding sugar moieties and endolectins in mouse submandibular glands. A glycohistochemical study.

The aims of this study were to assess histochemically by means of biotinylated lectins and neoglycoproteins the effects of castration and thyroidectomy on the expression of carbohydrate moieties and endogenous sugar-binding proteins (endolectins), respectively, in submandibular glands of mice. Characteristic binding patterns depending upon the type of lectin were observed primarily in the granular convoluted tubules. For the first time carbohydrate-binding sites were also localized in this glandular tissue. Moreover, the endocrine status was found to affect the histochemical expression of sugar moieties of glycoconjugates as well as endolectins, thus modifying both sides of presumed protein-carbohydrate interactions. Further work is needed to identify these molecules and to understand better their endogenous roles.

Animals↗
PubMedDate not supplied

Influence of culture media and multidrug resistance on the wheat germ agglutinin (WGA) glycocytochemical expression of two human glioblastoma cell lines.

Over the last two decades, many studies carried out with the aid of lectins have firmly established that cell glycans usually change in the course of the normal processes of growth and development, as well as in pathological situations. We describe here the in vivo binding expression of wheat germ agglutinin (WGA) to the U87 and U373 human glioblastoma cell lines exposed to various culture media i.e., media supplemented with either 10% (FCS10) or 1% (FCS1) fetal calf serum with or without 10 n Mol/l 17 beta-oestradiol (E2). After exposure to chemotherapeutic agents, the resistant variants (CR) developed by the two cell lines were also investigated. The quantitative cytochemical assessment of WGA binding was assessed by means of a cell image processor, which was also used to determine ploidy level (on Feulgen-stained nuclei) by means of DNA histogram typing (DHT). Our results clearly demonstrate that when U373 cells are cultured with E2, this steroid can modify the expression of WGA binding, whereas U87 cells were unaffected. Similarly, lowering the FCS level enhanced the WGA binding of the U373 cell line. Multidrug-resistant cell variants were associated with both aneuploidy and a dramatic decrease in cytochemical WGA expression.

Analysis of Variance↗
PubMedDate not supplied

Difference in glycohistochemical lectin staining of collagen fibers in the corpora cavernosa of normal and impotent men.

The objectives of this study were to investigate the value of glycohistochemical staining with three lectin types specific to a particular glycan structure (Arachis hypogaea [PNA], Triticum vulgare [WGA], and concanavalin A [Con A]) as a method of defining possible changes in the collagen structure in the corpora cavernosa in potent and impotent men. The study group consisted of 4 normal potent men and 22 men with various etiologies of impotence. The quantitative histochemical measurements were performed by means of a cell image processor. Two variables for each of the three types of lectins were studied. These were the mean optical density (MOD), which relates to glycohistochemical staining intensity, and the labeling index (LI), which is positively related to the percentage of immunostaining. Only WGA staining made it possible to discriminate significantly between the normal and pathological groups under study. The two parameters (LI, MOD) were significantly higher in the case of WGA staining in the normal group (P = 0.004 and 0.013, respectively). In contrast, only the mean LI value, in the case of the psychogenic and venogenic patients, reached a level of statistical significance (P = 0.005 and 0.001, respectively), when it increased from PNA through WGA to Con A histochemical staining. The two variables (LI, MOD) changed markedly from PNA through WGA to Con A in the arteriogenic patients (P = 0.003 and P < 0.001, respectively). WGA is of diagnostic value in distinguishing between normal and abnormal collagen in the corpora cavernosa. The difference in the lectin staining of the other groups, particularly the arteriogenic group, may be attributed to alterations in the glycosylation of the procollagen that are probably due to changes in the partial pressure of oxygen (PO2) level, an important cofactor in normal glycosylation. WGA staining may therefore be used as a marker to distinguish true psychogenic patients from those with organic diseases. Moreover, it may be used as an additional parameter in selecting the best candidates for penile revascularization.

Adult↗