Glycoprotein and carbohydrate binding protein expression in the placenta in early pregnancy loss

Glycoproteins expressed at the fetal-maternal interface have been shown to exert immunomodulating effects. Glycodelin, hCG and transferrin have been used in in vitro experiments as ligands to block E-selectin-mediated cell adhesion. We found that glycodelin is a strong inhibitor of the E-selectin-mediated cell adhesion with a 10(3)-fold increase in potency compared to the monovalent tetrasaccharide sialyl Lewis X. HCG with distinct carbohydrate expression is also an effective selectin antagonist, whereas the potency of transferrin is low. This could indicate a possible role of glycodelin, hCG and transferrin in preventing leukocyte adhesion to the fetal trophoblast. In decidual tissue of abortion patients, glycodelin expression was significantly reduced compared to normal gestation. These results were confirmed by in situ hybridization. Moreover, glycodelin expression in endometrial cells in vitro could be stimulated by addition of hCG. Because hCG is down-regulated in women with abortion, we speculate that hCG could be one of the factors regulating glycodelin expression. Galectins are structurally related proteins with the ability to bind beta-galactosides through a conserved carbohydrate recognition domain. Galectin-1 (gal-1) expression in the syncytiotrophoblast is down-regulated in early pregnancy loss. Gal-1 recognizes the Thomsen-Friedenreich disaccharide (Galbeta1-3GalNAc-) on the syncytiotrophoblast and extravillous trophoblast. Gal-1 also inhibited trophoblast cell proliferation but did not induce apoptosis in BeWo cells. Ligation of Gal-1 on trophoblast cells may have regulatory effects on trophoblast cell differentiation. Decreased expression of Gal-1 may partly explain disturbed trophoblast differentiation during early placentation leading to early pregnancy loss.

Volumetric ambient occlusion for real-time rendering and games

This new algorithm, based on GPUs, can compute ambient occlusion to inexpensively approximate global-illumination effects in real-time systems and games. The first step in deriving this algorithm is to examine how ambient occlusion relates to the physically founded rendering equation. The correspondence stems from a fuzzy membership function that defines what constitutes nearby occlusions. The next step is to develop a method to calculate ambient occlusion in real time without precomputation. The algorithm is based on a novel interpretation of ambient occlusion that measures the relative volume of the visible part of the surface's tangent sphere. The new formula's integrand has low variation and thus can be estimated accurately with a few samples.

Mikropartikel in der Frauenheilkunde

Mikropartikel (MP) werden bei Aktivierung oder Apoptose von zirkulierenden Blut- bzw. Endothelzellen sowie unter der Wirkung von Scherkräften freigesetzt. Sie nehmen u.a. Einfluss auf Gerinnung, Entzündungsprozesse und dienen als Transportmedium. Bislang gibt es wenige Untersuchungen zu zirkulierenden MP bei Patientinnen der Gynäkologie und Geburtshilfe. Erste Daten legen nahe, dass es zyklusabhängig Unterschiede in der Freisetzung von MP bei Frauen gibt und dass junge Frauen signifikant mehr Plättchen-MP und endotheliale MP aufweisen als altersentsprechende Männer. Pathologische Schwangerschaftsverläufe wie Abort und Präeklampsie gehen mit erhöhten MP-Konzentrationen einher. Inwieweit MP in die Pathophysiologie des Abortgeschehens bzw. der Präeklampsie eingreifen, ist Gegenstand weiterführender Untersuchungen. Studien an Mammakarzinom-Patientinnen legen nahe, dass die Konzentration zirkulierender MP mit dem Tumorstadium korreliert und MP ein ähnliches Sensitivitäts/Spezifitäts-Profil aufweisen wie etablierte Tumormarker.

[Microparticles and female issues]

Emerging evidence suggests that circulating, cell-derived microparticles (MP) play a role in various physiological and pathophysiological processes. MP are involved in coagulation, inflammation and transportation. The role of circulating MP in the field of obstetrics and gynaecology has been investigated only recently. Healthy women show menstrual cycle-specific differences in circulating MP which differ significantly from age-matched men. With regard to obstetrics, MP were elevated in subgroups of patients with miscarriage or preeclampsia. Whether MP contribute to the pathogenesis of the diseases themselves is part of ongoing research. Moreover, recent studies indicate MP levels parallel tumor invasiveness in breast cancer patients and show similar sensitivity-specificity profiles than established biomarkers.