The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Gerhard Leyendecker - One of the best experts on this subject based on the ideXlab platform.
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Uterine peristaltic activity during the menstrual cycle: characterization, regulation, function and dysfunction.
Reproductive biomedicine online, 2002Co-Authors: Georg Kunz, Gerhard LeyendeckerAbstract:Unlike other smooth muscle organs, the uterine muscle was regarded to be normally functional for only a brief period, following a lengthy gestation. However, recently it has been shown that uterine peristalsis constitutes one of the fundamental functions of the non-pregnant uterus. Its morphological basis is the archimyometrium, which is the muscular component of the archimetra and which preserves a functional bipartition of the primarily unpaired uterus. Three types of uterine peristaltic contractions can be distinguished: cervico-fundal, fundo-cervical and isthmical peristaltic activity, which changes during the menstrual cycle and is controlled by the dominant ovarian structure via the secretion of sex steroids Systemically and into the utero-ovarian vascular Countercurrent System. Uterine peristalsis of the non-pregnant uterus is actively involved in very early reproductive processes, such as rapid and sustained directed sperm transport and high fundal implantation, as well as serving retrograde menstruation for the preservation of body iron content. Furthermore, it became apparent that hyper- and dysfunctions of this contractile activity, such as hyper- and dysperistalsis, might be causally involved in the development of pelvic endometriosis, uterine adenomyosis and infertility, as obtained from immunohistochemistry, vaginal sonography, hysterosalpingoscintigraphy and magnetic resonance imaging.
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Uterine peristaltic activity during the menstrual cycle: characterization, regulation, function and
2001Co-Authors: Gerhard LeyendeckerAbstract:Unlike other smooth muscle organs, the uterine muscle was regarded to be normally functional for only a brief period, following a lengthy gestation. However, recently it has been shown that uterine peristalsis constitutes one of the fundamental functions of the non-pregnant uterus. Its morphological basis is the archimyometrium, which is the muscular component of the archimetra and which preserves a functional bipartition of the primarily unpaired uterus. Three types of uterine peristaltic contractions can be distinguished: cervico–fundal, fundo–cervical and isthmical peristaltic activity, which changes during the menstrual cycle and is controlled by the dominant ovarian structure via the secretion of sex steroids Systemically and into the utero-ovarian vascular Countercurrent System. Uterine peristalsis of the non-pregnant uterus is actively involved in very early reproductive processes, such as rapid and sustained directed sperm transport and high fundal implantation, as well as serving retrograde menstruation for the preservation of body iron content. Furthermore, it became apparent that hyperand dysfunctions of this contractile activity, such as hyper- and dysperistalsis, might be causally involved in the development of pelvic endometriosis, uterine adenomyosis and infertility, as obtained from immunohistochemistry, vaginal sonography, hysterosalpingoscintigraphy and magnetic resonance imaging.
L Wildt - One of the best experts on this subject based on the ideXlab platform.
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Uterine mechanisms of ipsilateral directed spermatozoa transport: Evidence for a contribution of the utero-ovarian Countercurrent System.
European journal of obstetrics gynecology and reproductive biology, 2009Co-Authors: I Zervomanolakis, H W Ott, J Müller, B E Seeber, S C Friess, V Mattle, I Virgolini, D Heute, L WildtAbstract:Spermatozoa transport into uterus and fallopian tubes is directed to the side of the dominant follicle and seems to be controlled by the ipsilateral ovary. The objective of this study was to evaluate the temperature in the fallopian tubes as well as the concentrations of estradiol and progesterone in the utero-ovarian veins draining the ipsilateral ovary and compare these to the contralateral side of the uterus. A prospective clinical study. Academic-assisted reproductive technology program. Temperature was measured in both oviducts of 10 patients each in the early phase as well as during the late follicular phase during the course of examination of tubal patency and function. Blood samples of the ovarian veins were obtained during hysterectomy in 10 premenopausal patients with regular menstrual cycles. Five of the women were in the early follicular phase and 5 were in the late follicular phase. Late follicular phase temperature as well as concentrations of estradiol and progesterone were significantly higher in the ipsilateral tube and the utero-ovarian veins draining the ipsilateral ovary as compared to the contralateral side. No such differences were found during the early follicular phase of the cycle. These data support our view that the uterus and fallopian tubes during the late follicular phase immediately before ovulation are composed of two functional units with different functional properties acting as a peristaltic pump resulting in increased transport of spermatozoa into the oviduct ipsilateral to the ovary bearing the dominant follicle and that this effect is mediated in part by the utero-ovarian Countercurrent System.
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Uterine mechanisms of ipsilateral directed spermatozoa transport: Evidence for a contribution of the utero-ovarian Countercurrent System
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2009Co-Authors: I Zervomanolakis, H W Ott, J Müller, B E Seeber, S C Friess, V Mattle, I Virgolini, D Heute, L WildtAbstract:Abstract Objective Spermatozoa transport into uterus and fallopian tubes is directed to the side of the dominant follicle and seems to be controlled by the ipsilateral ovary. The objective of this study was to evaluate the temperature in the fallopian tubes as well as the concentrations of estradiol and progesterone in the utero-ovarian veins draining the ipsilateral ovary and compare these to the contralateral side of the uterus. Study design A prospective clinical study. Setting Academic-assisted reproductive technology program. Subjects Temperature was measured in both oviducts of 10 patients each in the early phase as well as during the late follicular phase during the course of examination of tubal patency and function. Blood samples of the ovarian veins were obtained during hysterectomy in 10 premenopausal patients with regular menstrual cycles. Five of the women were in the early follicular phase and 5 were in the late follicular phase. Results Late follicular phase temperature as well as concentrations of estradiol and progesterone were significantly higher in the ipsilateral tube and the utero-ovarian veins draining the ipsilateral ovary as compared to the contralateral side. No such differences were found during the early follicular phase of the cycle. Conclusions These data support our view that the uterus and fallopian tubes during the late follicular phase immediately before ovulation are composed of two functional units with different functional properties acting as a peristaltic pump resulting in increased transport of spermatozoa into the oviduct ipsilateral to the ovary bearing the dominant follicle and that this effect is mediated in part by the utero-ovarian Countercurrent System.
G Leyendecker - One of the best experts on this subject based on the ideXlab platform.
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Oxytocin : a stimulator of directed sperm transport in humans
Reproductive biomedicine online, 2007Co-Authors: G Kunz, D Beil, P Huppert, G LeyendeckerAbstract:Rhythmic peristaltic contractions of the muscular wall of the non-pregnant uterus, as well as rapid sperm transport from the vagina to the Fallopian tubes, have long been documented by means of vaginal sonography and hysterosalpingoscintigraphy. Uterine peristaltic activity reaches a maximum before ovulation and is controlled via oestradiol secretion from the dominant follicle Systemically and into the utero-ovarian Countercurrent System; it is also enhanced by oxytocin. In this study, the effect of oxytocin and its receptor antagonist atosiban on uterine peristalsis and thus directed sperm transport during the mid and late follicular phases was examined. Atosiban did not show any effect either on frequency or on pattern of the peristaltic contractions. However, oxytocin significantly increased the rapid and directed transport of radiolabelled particles representing spermatozoa from the vagina into the Fallopian tube ipsilateral to the site of the dominant follicle (P = 0.02, 0.04 and 0.02 after 1, 16 and 32 min of documentation respectively). It seems reasonable to assume that oxytocin plays an important, although not critical, role in the mechanisms governing rapid sperm ascension that, at least in humans, were developed to rapidly preserve an aliquot of spermatozoa following intercourse.
Bernd Pelster - One of the best experts on this subject based on the ideXlab platform.
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Development of the swimbladder in the European eel (Anguilla anguilla)
Cell and Tissue Research, 2002Co-Authors: Petra Zwerger, Katharina Nimeth, Jürgen Würtz, Willi Salvenmoser, Bernd PelsterAbstract:The swimbladder of the adult eel, Anguilla anguilla , with its bipolar Countercurrent System, the rete mirabile, is a widely used model for swimbladder function, but very little is known about the development of this swimbladder. Our histological studies on the developing swimbladder revealed that during metamorphosis the swimbladder becomes present as a dorsal outgrowth of the esophagus. It is filled with surfactant, and gas was not detected in the swimbladder. In the young glass-eel, the epithelial (gas gland) cells of the swimbladder are columnar, but do not yet have the typical basolateral labyrinth established in adult animals. Few blood vessels are found in the swimbladder tissue, and the submucosa is present as a thick layer of connective tissue, giving a large diffusion distance between blood vessel and swimbladder lumen. Within the next 2 or 3 months of development, gas gland cells develop their typical basolateral labyrinth, and the thickness of the submucosa is significantly reduced, resulting in a short diffusion distance between blood vessels and the swimbladder lumen. The first filling of the swimbladder with gas is observed while the gas gland cells are still in a poorly differentiated status and it appears unlikely that these cells can accomplish their typical role in gas deposition. The presence of small gas bubbles in the swimbladder as well as in the ductus pneumaticus at the time of initial swimbladder inflation suggests that the swimbladder is filled by air gulping or possibly by taking up gas bubbles from the water.
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Countercurrent Concentration and Gas Secretion in the Fish Swim Bladder
Physiological Zoology, 1992Co-Authors: Bernd Pelster, Peter ScheidAbstract:Many fish possess a gas-filled swim bladder, and the gas molecules enter the bladder by diffusion from its capillaries and epithelium. The high gas partial pressures necessary to drive diffusion are produced in two steps. First, in the blood perfusing the swim bladder capillaries the physical solubility of gases is reduced via the salting-out effect, and gases are released from a chemical binding site via blood acidification (e.g., Root effect for O₂; conversion of HCO₃⁻ to CO₂). These effects result in an increase in the gas partial pressure in blood. In a second step, this initial increase in partial pressure (the "single concentrating effect") is multiplied by back diffusion of gas molecules in the Countercurrent System of the rete mirabile. For inert gases, the salting-out effect, induced by the release of lactic acid from the gas gland cells in the swim bladder tissue, results in a probably small reduction of solubility, while the acid-induced decrease in hemoglobin O₂-carrying capacity (Root effect)...
William H. Dantzler - One of the best experts on this subject based on the ideXlab platform.
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Changes in the Countercurrent System in the renal papilla: diuresis increases pH and HCO3− gradients between collecting duct and vasa recta
Pflugers Archiv : European journal of physiology, 1996Co-Authors: Kuramochi, Ulrich Kersting, Stefan Silbernagl, William H. DantzlerAbstract:This study was designed to elucidate the acidbase balance local to the collecting duct urine (CD) and vasa recta blood (VR) in the rat renal papilla in diuresis. The pH changes were measured in both a furosemide-induced and a volume-load-induced diuresis, whereas the PCO2 (i.e., CO2 tension) and HCO3− concentration were measured only in a furosemideinduced diuresis. In an antidiuresis, the pH of the VR was more acidic than that of the Systemic arterial blood (ΔpH = 0.44–0.73). Additionally, the pH of the ascending VR was significantly lower than that of the descending VR (ΔpH = 0.14–0.16). In diuresis, the pH of the CD decreased (ΔpH = 0.81–0.97), while the pH of the descending and the ascending VR increased; however, the increase was only significant in the ascending VR (ΔpH = 0.23–0.30). Consequently, the significant difference in the pH gradient between the descending and the ascending VR was eliminated. The PCO2 values in the CD and the ascending VR were not different from those in antidiuresis, while the HCO3− concentration in the CD and the ascending VR, respectively, decreased and increased significantly. Thus, in diuresis, the decrease in the pH of the CD and the increase in the pH of the ascending VR result, respectively, from the decrease and the increase in the HCO3− concentration, with no changes in the PCO2 values.
