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Biomedical subjects

Y Chambon

Publications and source records attributed to Y Chambon.

At least 19 recordsLinked to original sources

Inhibition of autophagy of fetal rabbit gonoducts by puromycin, tunicamycin and chloroquin in organ culture.

At the end of ambisexual stage, mullerian or wolffian ducts are programmed to die. Cell degeneration is initialized by an appearance of lysosomes, subsequently involved in invading autophagic vacuoles. In an organ culture assay, performed for 6 days, treatments by puromycin, tunicamycin and chloroquine, known to act on synthesis, transport and activation of lysosomal enzymes, were applied to inhibit the duct regression. Four situations were studied: female genital tract of 17 day post coitum (d.p.c.) cultured with differentiated testis of 19 d.p.c.; male genital ducts of 17 d.p.c. cultured without testis; female and male genital tracts of 17 d.p.c. cultured alone as controls. The stabilization of the mullerian duct cultured with testis and of the wolffian duct cultured without testis was obtained. Ultrastructuraly, the lysosomes were scarce or absent and no autophagic vacuoles were observed. In preventing the formation of lysosomes, it was possible to avoid the duct cell autophagy and to comfirm the existence of a wolffian lysosomal system spontaneously active when testosterone is absent, while a mullerian one spontaneously inactive when AMH is absent.

Animals↗

Elastin derived peptides protect elastic fibres degradation by human neutrophil elastase: in vitro and in vivo studies using a mechanically induced rat gingival inflammatory model.

An elastin peptide (kE57) obtained from organoalkaline hydrolysis of calf ligamentum nuchae insoluble elastin, was isolated by gel permeation on Sephadex G150 and high performance liquid chromatography on a TSK G 3000 SW column. It possessed an average Mr = 57,000 and similar amino acids composition as its insoluble counterpart. kE57 behave as a competitive inhibitor of human neutrophil elastase (HNE) with Ki = 1.4 microM; it also inhibited porcine pancreatic elastase (PPE) but less efficiently Ki = 180 microM. Identification of elastic fibres in rat gingiva was ascertained by light and electron microscopic studies. Morphometric studies indicated that rat gingiva contained similar levels of elastic fibres (= 2%) as human skin; elastic fibres networks from both tissues also displayed high structural analogy. Gingival chronic inflammation was induced in rats by mechanical impaction associated with an hyperglucidic diet. After 5 weeks, the levels of rat gingiva elastic fibres, decreased from Vv = 1.94 +/- 0.1% to Vv = 1.02 +/- 0.06%. Local injections of kE57: 100 micrograms per day, 5 days a week for 5 weeks did restore the integrity of the gingiva elastic fibres network: Vv = 1.84 +/- 0.1. Without influencing leucocyte infiltration, it is proposed that elastin-derived peptides, acting as potent competitive inhibitor of neutrophil elastase involved in periodontitis, might be of therapeutic value.

Animals↗

Ultrastructure of mullerian and wolffian ducts of fetal rabbit in vivo and in organ culture.

Emphasis is put on programmed cell death in the epithelial cells of mullerian and wolffian ducts, in rabbit fetuses, by observations on the timing and ultrastructural characteristics of cell degeneration. Genital tracts were collected on days 17 to 25 post-coitum and processed for electron microscopy. An organ culture assay was performed on fetal ducts and testis or ovary, for 4 days. Then, ducts and gonads were processed for electron microscopy. The involution of male mullerian and female wolffian ducts in culture and in vivo follows a similar pattern. Cell degeneration is initialized by an increase in the number of lysosomes which are subsequently involved in invading autophagic vacuoles. Cytochemical localizations of acid phosphatase and aminopeptidase indicate the presence of new lysosomes within the cells. In conclusion, this cell degeneration seems to be due to a double lysosome system in the rabbit urogenital ridge: A mullerian one spontaneously inactive when mullerian inhibiting substance is absent, and a wolffian one, spontaneously active when testosterone is absent. The organ culture is reliable for further attempts to study the responses to substances known to act on lysosome formation or activity.

Acid Phosphatase↗

[Synergism and antagonism between estrogens and progestins: an update].

Our purpose is to provide a review of studies performed since forty five years, concerning interactions of natural or synthetic estrogens and progestins. In this paper, the terms synergism and antagonism have to be considered in a broader sense than usually done. In addition to the classical concepts of succession and of simultaneity synergism between estradiol and progesterone, notions of "saving" and of "necessity" synergism came from decidualization studies in the rabbit (1949). The necessity synergism put definitively and end to the idea that estradiol was only a female hormone and progesterone a mother one. Our research in the field of ovum implantation showed also that estrogens might be secreted by mammalian ova (1949), which is now well established. The participation of estrogens to the process of decidualization in the rat suggested even (1958, 1959) their role in the starting implantation. From 1960, synthetic estrogens and progestins were tested, in a first step especially ethynylestradiol and chlormadinone acetate. In the rabbit and in the rat, these new tools permitted us to dissociate the hormonal needs of embryonic growth and of morphogenesis (1965). The studies related to the effects of these analogs upon the adrenal gland, as upon the hypophysis (1963), led to their clinical use in the treatment of advanced breast cancers, and the studies concerning their effects in the ovulation to the discovery of the antiovulatory synergism of synthetic estrogens and progestins (1966, 1982). These observations are in agreement with the Courrier rules with regard to the relationships between the relative, but also absolute, quantities of estradiol and of progesterone administered, and the obtained biological effects. Nevertheless, progestins exist with incomplete or, on the contrary, superfluous pharmacological activities. In the extreme, the estrogenic properties of norethisterone take precedence over its progestogenic properties when administered doses are growing (1977). These phenomena have now to be understood at a molecular level. Though explanations are presently available for some processes, many of them remain to day unexplained, and inversely other explanations are coming into sight.

Animals↗

[Behaviour of gingival elastic constituents in periodontal disease].

Disorganization of gingival elastic constituents, including oxytalan fibers, elaunin fibers, and mature elastic fibers, is a feature of periodontal disease. In early stages where inflammation is moderate, this disorganization involves only oxytalan fibers. As the disease progresses, fragmentation and lamination of elaunin fibers and mature elastic fibers is seen. In cyclosporin A-induced gingival hyperplasia, there is a substantial increase in the amount of elastic fibers as compared with healthy gingiva. In gingival fragments from edentulous elderly individuals the elastic constituents form dense granules.

Adult↗

Evolution of red blood cell polyamine levels in partially hepatectomized rat.

Erythrocyte levels of polyamines, especially of spermidine are greatly elevated during the course of liver regeneration. In contrast to putrescine and spermine levels, from the tenth hour to the fourth week after partial hepatectomy, correlation has been observed between the elevation of liver and erythrocyte spermidine concentrations. Substituting drinking water with 2% alpha difluoromethylornithine (alpha-DFMO) commencing 48 hr prior to partial hepatectomy and continuing until death, though ineffective in inhibition of liver [3H]-thymidine incorporation, prevented the rise in hepatic putrescine concentrations (without modifying those of spermidine and spermine) and correlatively decreased red blood cell (RBC) spermidine levels. Thus, an excess of liver spermidine produced from an excess of newly synthetized putrescine could be released in blood and taken up by erythrocytes, especially as affinity of RBC for spermidine is at least 30 fold higher than that for putrescine. In vivo the spermidine half-life in RBC was estimated to be 2.5-3.0 hr, which could explain the elevation of erythrocyte and liver spermidine levels. The elevation of erythrocyte spermidine concentration is not correlated to that of the regenerating liver weight but dependent on the extent of partial hepatectomy. The elevation of erythrocyte spermidine concentrations, which appeared to be linked to the cellular proliferating activity, could contribute to determine intratumoral proliferation in cancerous patients.

Animals↗

Diagnostic value of erythrocyte-free polyamines and histaminemia in malignant hepatic tumors and in liver cirrhosis.

The present study tries to evaluate the diagnosit value in malignant hepatic tumors of polyamines, of which the relationship with cellular kinetics is known, and histamine, of which catabolism follows a similar pathway. One hundred and fifty six patients were studied: 53 with malignant liver tumors (27 primary, 26 metastatic) and 103 with non-tumoral liver diseases of which 65 were cirrhotic and 38 non-cirrhotic. Erythrocyte polyamines (spermidine and spermine) and histamine levels were assayed. The results indicate the following. 1. Polyamine levels were significantly increased (a) in cirrhotic patients, not only when compared with controls (p less than 10(-8)), but also when compared with the non-cirrhotic patients (p less than 10(-7)); (b) in primary malignant hepatic tumors (p less than 10(-3)). 2. Histamine was significantly increased (a) in the non-tumoral liver diseases (p less than 10(-4)), but with no difference between cirrhotic and non-cirrhotic patients; (b) in the secondary malignant tumor patients, histamine levels were lower than in primary tumor patients (p less than 0.04). 3. There was no correlation, in all groups studied, between polyamine and histamine levels. These results suggest the following practical implications. 1. For non-tumor liver diseases, appreciably increased polyamine levels may represent a further argument favoring a cirrhotic condition. 2. In diagnosing hepatic scintigraphic defects, increased polyamine levels would suggest a primary malignant hepatic tumor; low histamine levels are more in favor of a secondary malignant hepatic process.

Adult↗

The hedgehog uterus. A comparative transmission electron-microscopic study.

The ultrastructure of the luminal epithelium of the hedgehog uterus is described on the basis of material taken from 11 animals in three different hormonal situations: castrated, active and hibernating animals. The whole uterine epithelium is composed of microvillous cells. Its appearance is very similar in ovariectomized and hibernating animals. It differs from that observed in active animals where the epithelium is taller, microvilli are more numerous and longer, and where nuclei and cytoplasm display a very active ultrastructural appearance. The results now available indicate that ultrastructural changes occurring within the cells are certainly correlated with plasma sex steroid hormone concentrations. The present paper also reports the regular occurrence of nuclear bodies in uterine cells.

Animals↗

Scanning electron microscopic study of hedgehog uteri.

Ultrastructural studies of hedgehog uteri (Erinaceus europaeus L.) have been made using animals in anestrus, in estrus and in estrus after sojourn of a week with a male. In estrus and anestrus the uterine epithelium is homogeneous, regularly interrupted by orifices of glands. It is composed of microvillous cells only. Microvilli decrease in number and length in anestrus. A new type of cell, a ciliated cell, appears after copulation. Probable correlation of ultrastructural aspects of endometrium with hormonal situation is discussed.

Animals↗

Implantation in the rabbit: ultrastructural features of nuclei involved in symplasm formation.

Mitoses, direct division or cell fusion are observed during symplasm formation in the rabbit uterus epithelium. These phenomenon are examined through transmission electron-microscopic studies. Two types of direct division are described: (1) nuclear scission after folding of the membrane and (2) nuclear scission by invagination of the membrane. The existence of amitoses has long been contested in mammals; the present study tends to show that direct division is not an accidental karyorrhexis but is organized at the cellular level.

Animals↗

[Y-chromosome polysomy and expression of the H-Y antigen].

The sex-differentiation H-Y antigen was studied in 5 males subjects with Y-chromosome polysomy. All had gonadal deficiency and significant decrease of H-Y antigen as compared with 77 normal 46, XY male controls. Men with additional Y-gonosomes may be hypogonadic or, more often, fertile, as was probably the case with the 3 patients with very high H-Y antigen titers previously described by other research workers. The phenotypic polymorphism of these subjects therefore seems to be parallel with their H-Y antigen polymorphism and there may be, in our 5 subjects, a relationship between abnormal spermatogenesis and H-Y antigen deficiency.

Adult↗

Ultrastructural aspects of the antimesometral implantation in the rabbit.

A scanning and transmission electron microscope study of blastocysts immediately prior to ovo implantation and of antimesometrial implantation sites was conducted. External membranes of the eggs showed at 6 days post coitum the imprint of the endometrial surface, pointing to the early establishment of contact between egg and uterus. At 7 days the antimesometrial region showed flattening with continued evidence of gland openings that appear to be the elective sites of attraction of the trophoblastic knobs. Attachment of the trophoblastic knobs followed on days 8 and 9.

Animals↗

[Infrahepatic bile duct proliferation in the gestating rat treated with 4,4'-diaminodiphenylmethane (4,4DDPM)].

We have attempted to produce experimentally the histological hepatic lesions observed in the case of biliary infant atresia. Though the etiopathogeny of this disease remains uncertain, the possibility of a toxic origin for the liver was evoked. Female rats were treated per os from the 10th to the 20th day of gestation with 44' DDPM, a molecule able to provoke an intra-hepatic biliary ductular proliferation. If we always observed hepatic lesions in pregnant rats sacrificed 24 hours before delivery, in some cases we also noticed the existence of macro- and microscopic hepatic lesions in the foetus. With a dose superior to LD 50, we have sometimes observed neural tube defects without hepatic lesions.

Aniline Compounds↗

[Blastocyst-endometrial relationships before ovo-implantation in the rabbit (author's transl)].

Transmission and scanning electron microscope appearances of epithelium in a pregnant uterine horn at and between the eggs, in a non-gravid horn of a unilaterally pregnant animal, and in the uterine horn of a pseudopregnant animal provided evidence of short-, medium- and long-range blastocyst effects. While cessation of mitotic division at 5 to 6 days post-coitum is solely the result of ovarian activity, the changes that occur in the shape of uterine epithelial cells apex seem to be due to the combined actions of ovaries and eggs. The development of apical club-shaped structures between 4 and 6 days, more pronounced in the pregnant horn compared with the pseudopregnant horn is apparently determined by ovarian and ovular effects. On the other hand, blastocysts induce the apparition of crater-cells at days 4 and 5 only in the pregnant horn : this could involve a mechanical or a chemical action of short- and medium-range egg effects. Similarly, on days 5 and 6, apical elongations are seen in the uterine regions occupied by the eggs, this finding points to a possible short-range blastocyst action.

Animals↗

[Effect of aminoguanidine sulfate on the hepatic level of polyamines after partial hepatectomy in rats].

The injection of amino-guanidine sulfate, which is a diamine-oxydase inhibitor to Wistar rats partially hepatectomized modifies the putrescine, spermidine and spermine liver concentrations, estimated by thin layer chromatography after dansylation. The three polyamines reach a peak three hours after the beginning of the treatment, then decrease six hours later, especially for putrescine and spermine. Forty eight hours later, the spermidine rate increase again to reach a level superior to that of animals which were only hepatectomized, whereas putrescine and spermine levels remain until about the fourth day inferior to those of control animals. Contrary to shamoperated rats, those injected with amino-guanidine sulfate show higher polyamine concentrations. These observations probably show a reduction of the activity of the diamine oxidase under the influence of amino-guanidine sulfate. According to those results, the action of amino-guanidine sulfate previously observed on the hyperplasic component of liver regeneration, doesn't seem to have an effect upon diamine oxidase.

Amine Oxidase (Copper-Containing)↗

Testosterone and 5 alpha-dihydrotestosterone concentrations in human seminal plasma.

Testosterone and dihydrotestosterone (DHT) were estimated by radioimmunoassay in human seminal plasma. Testosterone concentrations showed no significant differences between fertile and infertile semen samples, whereas DHT concentrations were significantly lower in azoospermic and oligozoospermic samples. It is concluded that testosterone derives essentially from the accessory sex glands, whereas DHT is mainly of testicular or epididymal origin. The low DHT concentrations found in seminal plasma of oligozoospermic and azoospermic patients is probably due to defective epididymal conversion of testosterone to DHT.

Dihydrotestosterone↗

[Comparative study of the progestomimetic and contraceptive activity of quingestanol acetate with 5 other progestational molecules].

The progestomimetic, contraceptive activities of quingestanol acetate are compared to those of five molecules (chlormadinone acetate, norgestrel, progesterone, norethisterone acetate, lynestrol). In the opinion of the authors, the therapeutic efficacity of contraceptive pills cannot be judged solely according to the weight of their various ingredients. An appreciation of the value of the various substances is based on a comparison between their physiological activity and their weight. The concept of a mini-dosage pill should therefore be considered, and due consideration paid to the physiological activity of each ingredient. In the experiments described here, quingestanol acetate shows marked statistical differences to the other five molecules.

Animals↗