Influence of the microenvironment on invasiveness of human bladder carcinoma cell lines

To investigate the importance of the microenvironment in bladder cancer invasion, a panel of six bladder carcinoma cell lines (SD, RT112, JON, 1207, T24, and J82) was tested in both in vitro and in vivo invasion assays. Furthermore, invasiveness was correlated with the expression of components of the E-cadherin-catenin complex. The E-cadherin-negative cell lines, T24 and J82, displayed a high in vitro invasive capacity, whereas the E-cadherin-positive cell lines, SD and JON, completely lacked in vitro invasive capacity. In contrast, in vivo invasion was noted for all cell lines, with the exception of cell line JON. Most notably, SD formed highly invasive tumors in vivo. The in vivo invasiveness of the E-cadherin-positive bladder carcinoma cell lines was associated with a heterogeneous expression of the E-cadherin-catenin complex. The discrepancy between in vitro and in vivo invasive behavior implies that, in vivo, the microenvironment plays an important role in the establishment of the invasive phenotype. In addition, it was found that orthotopic xenografting of 1207 and T24 bladder carcinoma cells resulted in site-specific tumor take and an enhanced tumor outgrowth and invasiveness, respectively, compared with heterotopic (i.e., subcutaneous) inoculation. We conclude that the site-specific growth and invasion of the bladder carcinoma cell lines in vivo and the observed assay specific invasion (in vitro vs in vivo) points to an effect of the local (bladder) microenvironment on tumor cell behavior.     

Image quality assessment using the CD-DISC phantom for vascular radiology and vascular surgery

The purpose of the study was to evaluate image quality (IQ) associated with vascular radiology and vascular surgery procedures in Belgium and to determine reference values for future image quality assessment. IQ was evaluated with the CD-DISC contrast-detail phantom. This circular PMMA phantom contains 225 holes with different diameter and depth, to quantify resolution and contrast. Images of the phantom were acquired for both fluoroscopy and subtraction images on 21 systems. Three observers evaluated the images by determining the threshold contrast visible for every diameter. This results in contrast-detail curves and image quality figures. We observed a large difference in IQ between the centres. No straightforward correlation could be found with radiation dose or other exposure settings. A comparison was made with the image quality evaluation of the systems performed with the TOR[18FG] phantom for fluoroscopy. There is no clear correlation observed between the results of the CD-DISC phantom and the TOR phantom. However, systems with very poor or very good image quality could be detected by both phantoms. An important result is that a 75th percentile reference contrast-detail curve could be proposed to separate the best centres from these with poorer quality. Some centres had also a significantly better image quality than others. Therefore, we introduced also a 25th percentile. Centres with IQ above this value are recommended to lower the dose and work with acceptable rather than excellent image quality. The CD-DISC phantom thus allows to guide the image quality setting.     

Chorioallantoic membrane capillary bed: A useful target for studying angiogenesis and anti-angiogenesis in vivo

The chick embryo chorioallantoic membrane (CAM) is an extraembryonic membrane that is commonly used in vivo to study both angiogenesis and anti-angiogenesis. This review 1) summarizes the current knowledge about the structure of the CAM's capillary bed; 2) discusses the controversy about the existence of a single blood sinus or a capillary plexus underlying the chorionic epithelium; 3) describes a new model of the CAM vascular growth, namely the intussusceptive mode; 4) reports findings regarding the role played by endogenous fibroblast growth factor-2 in CAM vascularization; and 5) addresses the use and limitations of the CAM as a model for studying angiogenesis and anti-angiogenesis. Anat Rec 264:317–324, 2001. © 2001 Wiley-Liss, Inc.     

JAK/STAT pathway mediates retinal ganglion cell survival after acute ocular hypertension but not under normal conditions

Intraocular pressure (IOP) elevation is an important cause of glaucoma. Animal models of ocular hypertension have been widely used to mimic glaucoma to investigate the mechanisms underlying retinal ganglion cell (RGC) death and search for possible cure. The aim of the present study was to examine the role of JAK/STAT pathway in RGC viability in normal condition or after acute IOP elevation. Retinal explants obtained from intact or IOP-elevated eyes were firstly used to examine the effect of the JAK/STAT pathway inhibitors, AG490 and Jak Inhibitor I, on RGC viability in vitro. The role of this signal pathway was further investigated and confirmed in vivo. AG490 and Jak Inhibitor I were applied into the left eye on days 3, 9, and 15 post 2-h IOP elevation at 110mmHg. Fluorescence dye Fluorogold was used to retrogradely label surviving RGCs. Because macrophage recruitment was seen in the IOP-elevated eyes after inhibition of this pathway, clodronate liposomes were used to remove phagocytic cells in the eye and examine the role of JAK/STAT pathway in RGC survival independent of macrophages. Activities and location of JAK/STAT pathway in the retina were examined using Western blotting and immunohistochemistry. We found that inhibition of JAK/STAT pathway did not affect RGC survival in the retinal explants derived from intact eye but caused RGC death in the retinal explants that were derived from IOP-elevated eye. Importantly, the detrimental effect of JAK/STAT pathway inhibition on RGC survival was also observed in vivo following acute IOP elevation, but not in intact eye. In addition, both in vitro and in vivo experiments confirmed a detrimental action of phagocytic cells following acute IOP elevation and the pathway inhibition. Compatible with what were observed in vivo, Western blotting and immunohistochemistry showed that JAK/STAT activities were not present in intact retina, but acute IOP elevation activated JAK/STAT pathway in the retina, in the regions of inner nuclear layer and ganglion cell layer, including RGCs. The IOP elevation-induced JAK/STAT activities were effectively abolished by intravitreal application of AG490. This study thus shows that (1) acute IOP elevation activates JAK/STAT pathway in RGCs, and (2) JAK/STAT pathway mediates RGC survival following IOP elevation but not under normal condition.     

Reduced right ventricular ejection fraction in endurance athletes presenting with ventricular arrhythmias: a quantitative angiographic assessment.

AIMS: Spontaneous or inducible sustained ventricular arrhythmias (VA) in endurance athletes frequently originate from the right ventricle (RV), even in the absence of familial arrhythmogenic RV cardiomyopathy (ARVC). The goal of this study was to determine whether the RV arrhythmogenic predilection in these patients is associated with RV functional abnormalities. METHODS AND RESULTS: Biplane RV angiography was performed in three groups: 22 endurance athletes with VA, 15 matched athletes without VA, and 10 non-athletes without VA. Four methods for quantitative RV angiographic analysis (area length, Boak, pyramid monoplane, and pyramid biplane) were used to calculate RV end-diastolic volume (EDV) and end-systolic volume (ESV) (both corrected for body surface area) and ejection fraction (EF). In addition RV outflow tract shortening fraction (SF) was determined. Although only 6 of 22 (27%) athletes with VA fulfilled the diagnostic criteria for ARVC, RV arrhythmogenic involvement was manifest or probable in 82%, based on a combination of electrophysiologic, electrocardiographic, and morphologic criteria. RV EDV in athletes was higher than in non-athletes (area length: 100.3 +/- 26.9 vs. 69.6 +/- 14.3 mL/m(2), P = 0.001), without significant difference between athletes with and without VA. RV ESV, in contrast, was significantly higher in athletes with VA than in athletes without VA (52.6 +/- 22.3 vs. 35.5 +/- 11.2 mL/m(2), P = 0.004), resulting in a significantly lower RV EF, a consistent finding across all methods (area length: 49.1 +/- 10.4 vs. 63.7 +/- 6.4%, P < 0.001). This functional impairment was also reflected in a lower RV outflow tract SF (SF right anterior oblique 32.2 +/- 10.1 vs. 40.0 +/- 11.6%, P = 0.09; SF left anterior oblique (LAO) 31.9 +/- 7.8 vs. 39.0 +/- 10.5%, P = 0.10). CONCLUSION: VA in high-level endurance athletes frequently originate from a mildly dysfunctional RV. This raises the question whether endurance exercise not only acts as a trigger for these arrhythmias but also as promoter of the RV changes.     

A novel mechanism of complement-independent clearance of red cells deficient in glycosyl phosphatidylinositol-linked proteins

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia characterized by the increased sensitivity of red blood cells (RBCs) to complement, leading to intravascular hemolysis and hemoglobinuria. PNH is due to the expansion of a cell clone that has acquired a mutation in the PIGA gene. Mice with targeted Piga gene inactivation genetically mimic the human disease and have phosphatidylinositol glycan class A-negative (PIGA-) RBCs with a reduced half-life in circulation. Although PIGA-RBCs are hypersensitive to complement in vitro, their complement sensitivity in vivo is barely detectable. Here we show that the shortened survival of PIGA- RBCs is independent of complement either by using inhibitory C5 antibodies or by transfusion into C5-, C4-, C3-, or factor B-deficient mice. Splenectomy or high-dose cortisone treatment had no effect on the shorter survival of PIGA- RBCs. However, treatment with liposome-encapsulated clodronate, an agent that depletes macrophages in vivo, normalized the half-life of PIGA- RBCs. This indicates that the shortened survival of PIGA- RBCs is due to a novel pathway of PIGA- RBC clearance that is mediated by macrophages, but occurs independently of complement. Future investigations will show whether this novel pathway of PIGA- RBC destruction identified in mice may also operate in patients with PNH.