Immunolocalisation de la relaxine dans les ovaires de souris

En 1926, F.L. Hisaw suggère l’existance, chez le cobaye, d’une contrôle hormonal du relâchement de la symphyse pubienne pendant la gestation. En 1930, Fevold et coll. trouvent ce facteur dans un extrait aqueux de corps jaune de truie gravide et la nomment RELAXINE. Dès le début, la relaxine a été reconnue comme une hormone de grosses. De nombreux travaux chez l’animal ont mis en évidence les fonctions principales de la relaxine pendant la gestation, comme le relâchement de la symphyse pubienne (Hisaw, 1926), l’inhibition des contractions utérines (Krantz et col., 1950), l’augemntation de l’extensibilité du col utérin (Fiels et Larkin, 19580) ou encore, son implication probable dans la rupture spontanée des membranes fœtales humaines (Koay et coll., 1986). En plus, l’administration de relaxine porcine purifiée à des femmes préparturientes la facilité la dilation du col et la parturition (Mac Lennan et coll., 1980). L’effet trophique de la relaxine sur l’utérus (Steinetz et coll., 1957a), son implication dans l’ovulation (Chihal et Espey, 1973) et dans le transport du sperme (Bryant-Greenwood, 1982) ont aussi été démontrés en dehors de la gestation. Cependant, aucune été pathologiques, lié à une hypo- ou hypersécrétion de relaxine, n’a pu être décrit. Dans notre « Laboratoire de Recherche e, Physiologie de la Reproduction Humaine » nous avons voulu étudier l’origine de la relaxine. Pour des raisons éthiques, l’étude de l’évolution du contenu ovarien en relaxine pendant la grossesse n’était pas possible chez le femme. Nous avons donc choisi de rechercher, l’origine de la relaxine qui apparaît au cours de la gestation (O’Byrne et Stienetz, 1976) et sa présence éventuelle en dehors de la gestation, dans les ovaires de sourisThèse de doctorat en sciences biomédicales (biologie de la reproduction) -- UCL, 199

Screening of conditions for rapid freezing of human oocytes: preliminary study toward their cryopreservation.

One hundred and twenty-one freshly-collected human oocytes and 839 unfertilized human oocytes after insemination were cryopreserved by vitrification. The cryoprotectants used were dimethylsulfoxide (DMSO) and sucrose. Vital staining and morphological criteria were used to assess injuries to cells. Variation of the time exposure to DMSO and sucrose, and cryoprotectants concentrations, followed by extraction-dilution in sucrose without freezing made it possible to study chemical toxicities. Variation of cryoprotectant concentrations followed by immersion in liquid nitrogen, thawing, extraction, and dilution made it possible to choose optimal conditions for vitrification. The sucrose concentration upon extraction after freezing and thawing which was lower than that during soaking enhanced the oocyte survival rate as did the choice of duration and temperature of soaking. No parthenogenetical activation of these unfertilized ovum was observed. This study indicates that with a certain combination of DMSO and sucrose concentrations up to 80% of morphologically intact human oocytes can be recovered after rapid freezing and thawing

Changes of relaxin concentrations determined by immunodensitometry in ovaries of NMRI mice during pregnancy.

Relaxin has been localized in corpora lutea (CL) of pregnant NMRI mice using the avidin-biotin complex immunocytochemical procedure and an antiserum against highly purified porcine relaxin. The immunostaining was measured by immunodensitometry. Relaxin immunostaining was first observed in luteal cells of type I gestational CL on day 11.5 (D11.5). For each investigated day, all CL were identically stained, and immunostaining was evenly dispersed all over the CL. Seventy-five percent of cells were stained at D11.5, and nearly all cells were stained between D13.5 and D18.5. The staining intensity increased throughout the last half of pregnancy, reaching a maximum at D18. A few hours before parturition, at D18.5, relaxin immunostaining decreased dramatically and reached the background level shortly after delivery. From our results we may conclude that, in murine CL, the number of relaxin-secreting cells and the intracellular storage of the peptide increase during pregnancy. The disappearance of relaxin with the cells occurs rapidly +/- 12 h before parturition

Evolution of NMRI mice ovaries and corpora lutea during pregnancy: morphologic and morphometric study.

During pregnancy in mice, three groups of corpora lutea (CL) originating from 4 successive ovulatory cycles could be distinguished taking into account their size, cellular structure and stain affinity. Type I CL originated at the onset of pregnancy, type II CL originated during the 2 previous estrous cycles and type III CL were produced during a cycle preceding the two others. CL volume of type I increased 10-fold between day 0 and day 18.5, a 2.5-fold increase in volume occurred in type II CL between day 0 and day 3, although they derived from cycles preceding pregnancy. The volume of type III remained unchanged. This fact suggested that types I and II CL probably play a functional role in the ongoing pregnancy. After day 10 of pregnancy a high correlation coefficient (r = 0.933) is observed between type I CL and the number of embryos in the corresponding uterine horn

A MICROSCOPIC MODEL OF ELECTRON-TRANSFER AT ELECTROACTIVE SITES OF MOLECULAR DIMENSIONS FOR REDUCTION OF CYTOCHROME-C AT BASAL-PLANE AND EDGE-PLANE GRAPHITE-ELECTRODES

A microscopic model of electron transfer, which assumes that electron transfer occurs only after radial diffusion to oxygen-functionalized sites of molecular dimension in size, has been developed to explain the electrochemical reduction of horse heart cytochrome c at graphite electrodes. By use of this model, the conclusion is reached that the rate of electron transfer is greater than 1 cm s-1 at both basal- and edge-plan graphite electrodes and silanized or "aged" graphite electrodes. According to the microscopic model, differences in shapes of cyclic voltammograms observed at basal-plane, edge-plane, and silanized or aged elctrodes are a result of different densities of electroactive sites and not variations in the heterogeneous rate of electron transfer as proposed previously based on the use of the macroscopic model which assumes that mass transport occurs via linear diffusion. The basal-plane electrode or silanized or aged adge-plane electrodes have a low surface density of oxygen-functionalized electroactive sites, and therefore radial diffusion is the dominant mode of mass transport. Sigmoidal-shaped voltammograms, corresponding to a reversible one-electron reduction process, are observed under these conditions. In contrast, edge-plane (high oxygen content) or polished basal-plane (medium oxygen content) have a higher density of electroactive sites. Under these conditions, diffusion layers overlap, thus destroying the radial diffusion terms. Peak-shaped curves are observed when linear, rather than radial, diffusion becomes the dominant mode of mass transport. This is the case at edge-plane and polished basal-plane electrodes. However, the peak-shaped curves still correspond to a reversible electron-transfer step. The concept that the heterogeneous rate of electron transfer to oxygen-functionalized electroactive sites is extremely fast for electrochemical reduction of cytochrome c at graphite electrodes is consistent with the fast homogeneous rates of chemical redox reactions that have been reported for cytochrome c. The microscopic model of reversible (fast) electron transfer rationalizes existing electrochemical data available for reduction of cytochrome c at graphite electrodes in a superior way to the classical macroscopic model in which variable rates of quasi-reversible electron transfer occur at electroactive sites having a relatively large surface area. © 1989 American Chemical Society

Evaluation of a synthetic serum substitute to replace fetal cord serum for human oocyte fertilization and embryo growth in vitro.

A comparison was made between a serum substitute. UltroSer G (Gibco, Ghent, Belgium) (2%) (medium B) and 10% human fetal cord serum (medium A), as regards their ability to support 1-cell and 2-cell mice embryo development in vitro. Sixty percent and 56% of the 1-cell embryos reached the expanded blastocyst stage when cultured in media A and B, respectively. Eighty-four percent and 88% of 2-cell embryos reached the expanded blastocyst stage when cultured in media A and B, respectively. A prospective randomized study was then performed to evaluate this synthetic serum substitute in human in vitro fertilization. Among 141 ovum pick-up (OPU), oocytes retrieved in 74 cases were processed in medium A and oocytes retrieved in 67 others in medium B. In media A and B, the fertilization rate was 67% and 44.3% respectively, and the pregnancy rate/OPU 23% and 9%, respectively. The pregnancy rate/transfer was 28.8% and 12.2% respectively, and the implantation rate/transferred embryo 9.5% and 4.2%. In the human sperm survival assay, the vitality and residual motility after 24 hours of incubation were significantly lower in medium B. In conclusion, UltroSer G successfully sustained the development in vitro of mouse embyros. However in human, it reduced sperm survival, oocyte fertilization, and embryo viability

ELECTROCHEMISTRY OF CYTOCHROME-C, PLASTOCYANIN, AND FERREDOXIN AT EDGE-PLANE AND BASAL-PLANE GRAPHITE-ELECTRODES INTERPRETED VIA A MODEL BASED ON ELECTRON-TRANSFER AT ELECTROACTIVE SITES OF MICROSCOPIC DIMENSIONS IN SIZE

The electrochemistry of a range of electron-transfer proteins at edge- and basal-plane graphite electrodes has been reconsidered using a microscopic model, which involves fast electron transfer at very small oxygen-containing electroactive surface sites. This model assumes that mass transport to the electrode occurs by radial diffusion when the density of the surface active sites is low (as is generally true in the case of the basal-plane graphite electrode) and by linear diffusion when the density of the active sites is increased sufficiently to cause overlap of the diffusion layers. With this model it is now proposed that the electrochemistry of cytochrome c, plastocyanin, and ferredoxin occurs with a very fast rate of charge transfer (≥1 cm s-1) at both edge- and basal-plane graphite electrodes. Critical factors, such as the mode of surface preparation (including covalent derivatization), the pH, and the presence in the electrolyte of cations such as Mg2+ or Cr(NH3)63+, control the density of surface sites, which result in the electrochemistry of a specific protein. This contrasts with the conclusion that has been reached previously based upon a conventional macroscopic model, which supposes that the rate of electron transfer is subject to enhancement or depression through these factors. The proposal that the electron-transfer process at the protein-graphite electrode interface is very fast over a wide range of conditions is now consistent with homogeneous kinetic studies where electron-transfer reactions of proteins, particularly amongst physiological partners, are also known to be fast. © 1989 American Chemical Society

Impact des vieillissements physiologique et pathologique sur la relation sexuelle

Numerous authors on sexual behaviors have studied the link between the persistence of a sexually active life and progressive aging. The knowledge of sexual health in the elderly has shown that biological sexual aging is extremely diverse and heterogeneous in men as well as in women, and contradicts the stereotype of age that would inevitably alter the sexual biological response in each human. Sexual diseases (lubrication, dyspareunia, erectile dysfunction, inability to achieve orgasm) and diseases of aging that impact sexual function have a growing incidence but don't never touch 100% of individuals. There is a decline in sexual interest correlated with the life-span, but the negative effects of age on desire are related to health problems. Moreover, sexual desire is more correlated with personal attitudes toward sexuality than with biological factors and diseases. Several predictors account for the pursuit of an active sexuality (including the presence of a partner, good health, having good sexual self-esteem, enjoyable past experience, an attitude that values the importance of sex in couple relationship), but the most decisive factor to successfully face the specific markers of aging is the ability to adapt to a more sensory sexuality, less focused on performance and coitus.SCOPUS: re.jinfo:eu-repo/semantics/publishe

A MICROSCOPIC MODEL OF ELECTRON-TRANSFER AT ELECTROACTIVE SITES OF MOLECULAR DIMENSIONS FOR REDUCTION OF CYTOCHROME-C AT BASAL-PLANE AND EDGE-PLANE GRAPHITE-ELECTRODES

A microscopic model of electron transfer, which assumes that electron transfer occurs only after radial diffusion to oxygen-functionalized sites of molecular dimension in size, has been developed to explain the electrochemical reduction of horse heart cytochrome c at graphite electrodes. By use of this model, the conclusion is reached that the rate of electron transfer is greater than 1 cm s-1 at both basal- and edge-plan graphite electrodes and silanized or "aged" graphite electrodes. According to the microscopic model, differences in shapes of cyclic voltammograms observed at basal-plane, edge-plane, and silanized or aged elctrodes are a result of different densities of electroactive sites and not variations in the heterogeneous rate of electron transfer as proposed previously based on the use of the macroscopic model which assumes that mass transport occurs via linear diffusion. The basal-plane electrode or silanized or aged adge-plane electrodes have a low surface density of oxygen-functionalized electroactive sites, and therefore radial diffusion is the dominant mode of mass transport. Sigmoidal-shaped voltammograms, corresponding to a reversible one-electron reduction process, are observed under these conditions. In contrast, edge-plane (high oxygen content) or polished basal-plane (medium oxygen content) have a higher density of electroactive sites. Under these conditions, diffusion layers overlap, thus destroying the radial diffusion terms. Peak-shaped curves are observed when linear, rather than radial, diffusion becomes the dominant mode of mass transport. This is the case at edge-plane and polished basal-plane electrodes. However, the peak-shaped curves still correspond to a reversible electron-transfer step. The concept that the heterogeneous rate of electron transfer to oxygen-functionalized electroactive sites is extremely fast for electrochemical reduction of cytochrome c at graphite electrodes is consistent with the fast homogeneous rates of chemical redox reactions that have been reported for cytochrome c. The microscopic model of reversible (fast) electron transfer rationalizes existing electrochemical data available for reduction of cytochrome c at graphite electrodes in a superior way to the classical macroscopic model in which variable rates of quasi-reversible electron transfer occur at electroactive sites having a relatively large surface area. © 1989 American Chemical Society

[Invitro Fertilization At Cliniques-universitaires-saint-luc in Brussels (results From October 1986 To December 1989)]

During this period, 591 patients were treated by in vitro fertilization (IVF) at the Cliniques Universitaires Saint-Luc in Brussels and 1 399 ovarian stimulation cycles, 1 242 retrievals, 968 transfers and 234 pregnancies were reported. There were 140 live deliveries. The outcome of IVF treatment cycles were evaluated according to woman's age, etiology of infertility, rank of cycle, quantities of oocytes and transferred embryos