Benchmarking the CoW with the TopCoW Challenge: Topology-Aware Anatomical Segmentation of the Circle of Willis for CTA and MRA.

The Circle of Willis (CoW) is an important network of arteries connecting major circulations of the brain. Its vascular architecture is believed to affect the risk, severity, and clinical outcome of serious neuro-vascular diseases. However, characterizing the highly variable CoW anatomy is still a manual and time-consuming expert task. The CoW is usually imaged by two angiographic imaging modalities, magnetic resonance angiography (MRA) and computed tomography angiography (CTA), but there exist limited public datasets with annotations on CoW anatomy, especially for CTA. Therefore we organized the TopCoW Challenge in 2023 with the release of an annotated CoW dataset. The TopCoW dataset was the first public dataset with voxel-level annotations for thirteen possible CoW vessel components, enabled by virtual-reality (VR) technology. It was also the first large dataset with paired MRA and CTA from the same patients. TopCoW challenge formalized the CoW characterization problem as a multiclass anatomical segmentation task with an emphasis on topological metrics. We invited submissions worldwide for the CoW segmentation task, which attracted over 140 registered participants from four continents. The top performing teams managed to segment many CoW components to Dice scores around 90%, but with lower scores for communicating arteries and rare variants. There were also topological mistakes for predictions with high Dice scores. Additional topological analysis revealed further areas for improvement in detecting certain CoW components and matching CoW variant topology accurately. TopCoW represented a first attempt at benchmarking the CoW anatomical segmentation task for MRA and CTA, both morphologically and topologically.

Cysteamine prevents vascular leakage through inhibiting transglutaminase in diabetic retina.

Cysteamine (an aminothiol), which is derived from coenzyme A degradation and metabolized into taurine, has beneficial effects against cystinosis and neurodegenerative diseases; however, its role in diabetic complications is unknown. Thus, we sought to determine the preventive effect of cysteamine against hyperglycemia-induced vascular leakage in the retinas of diabetic mice. Cysteamine and ethanolamine, the sulfhydryl group-free cysteamine analogue, inhibited vascular endothelial growth factor (VEGF)-induced stress fiber formation and vascular endothelial (VE)-cadherin disruption in endothelial cells, which play a critical role in modulating endothelial permeability. Intravitreal injection of the amine compounds prevented hyperglycemia-induced vascular leakage in the retinas of streptozotocin-induced diabetic mice. We then investigated the potential roles of reactive oxygen species (ROS) and transglutaminase (TGase) in the cysteamine prevention of VEGF-induced vascular leakage. Cysteamine, but not ethanolamine, inhibited VEGF-induced ROS generation in endothelial cells and diabetic retinas. In contrast, VEGF-induced TGase activation was prevented by both cysteamine and ethanolamine. Our findings suggest that cysteamine protects against vascular leakage through inhibiting VEGF-induced TGase activation rather than ROS generation in diabetic retinas.

Essential Role of Transglutaminase 2 in Vascular Endothelial Growth Factor-Induced Vascular Leakage in the Retina of Diabetic Mice.

Diabetic retinopathy is predominantly caused by vascular endothelial growth factor (VEGF)-induced vascular leakage; however, the underlying mechanism is unclear. Here we designed an in vivo transglutaminase (TGase) activity assay in mouse retina and demonstrated that hyperglycemia induced vascular leakage by activating TGase2 in diabetic retina. VEGF elevated TGase2 activity through sequential elevation of intracellular Ca(2+) and reactive oxygen species (ROS) concentrations in endothelial cells. The TGase inhibitors cystamine and monodansylcadaverin or TGase2 small interfering RNA (siRNA) prevented VEGF-induced stress fiber formation and vascular endothelial (VE)-cadherin disruption, which play a critical role in modulating endothelial permeability. Intravitreal injection of two TGase inhibitors or TGase2 siRNA successfully inhibited hyperglycemia-induced TGase activation and microvascular leakage in the retinas of diabetic mice. C-peptide or ROS scavengers also inhibited TGase activation in diabetic mouse retinas. The role of TGase2 in VEGF-induced vascular leakage was further supported using diabetic TGase2(-/-) mice. Thus, our findings suggest that ROS-mediated activation of TGase2 plays a key role in VEGF-induced vascular leakage by stimulating stress fiber formation and VE-cadherin disruption.

Dammarenediol-II Prevents VEGF-Mediated Microvascular Permeability in Diabetic Mice.

Diabetic retinopathy is a major diabetic complication predominantly caused by vascular endothelial growth factor (VEGF)-induced vascular permeability in the retina; however, treatments targeting glycemic control have not been successful. Here, we investigated the protective effect of dammarenediol-II, a precursor of triterpenoid saponin biosynthesis, on VEGF-induced vascular leakage using human umbilical vein endothelial cells (HUVECs) and diabetic mice. We overproduced the compound in transgenic tobacco expressing Panax ginseng dammarenediol-II synthase gene and purified using column chromatography. Analysis of the purified compound using a gas chromatography-mass spectrometry system revealed identical retention time and fragmentation pattern to those of authentic standard dammarenediol-II. Dammarenediol-II inhibited VEGF-induced intracellular reactive oxygen species generation, but it had no effect on the levels of intracellular Ca(2+) in HUVECs. We also found that dammarenediol-II inhibited VEGF-induced stress fiber formation and vascular endothelial-cadherin disruption, both of which play critical roles in modulating endothelial permeability. Notably, microvascular leakage in the retina of diabetic mice was successfully inhibited by intravitreal dammarenediol-II injection. Our results suggest that the natural drug dammarenediol-II may have the ability to prevent diabetic microvascular complications, including diabetic retinopathy.

TRAIL negatively regulates VEGF-induced angiogenesis via caspase-8-mediated enzymatic and non-enzymatic functions.

Solid tumors supply oxygen and nutrients required for angiogenesis by producing vascular endothelial growth factor (VEGF). Thus, inhibitors of VEGF signaling abrogate tumor angiogenesis, resulting in the suppression of tumor growth and metastasis. We here investigated the effects of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on VEGF-induced angiogenesis. TRAIL inhibited VEGF-induced in vitro angiogenesis of human umbilical vein endothelial cells (HUVECs) and in vivo neovascularization in chicken embryos and mice. TRAIL blocked VEGF-induced angiogenic signaling by inhibiting ERK, Src, FAK, paxillin, Akt, and eNOS. Further, TRAIL blocked intracellular Ca(2+) elevation and actin reorganization in HUVECs stimulated with VEGF, without inhibiting VEGF receptor-2 tyrosine phosphorylation. TRAIL increased caspase-8 activity, without inducing caspase-9/-3 activation and apoptosis. Moreover, TRAIL resulted in cleavage of FAK into FAK-related non-kinase-like fragments in VEGF-stimulated HUVECs, which was blocked by a caspase-8 inhibitor and cellular caspase-8-like inhibitory protein. Biochemical and pharmacological inhibition of caspase-8 and FAK blocked the inhibitory effects of TRAIL on VEGF-stimulated anti-angiogenic signaling and events. In addition, caspase-8 knockdown also suppressed VEGF-mediated signaling and angiogenesis, suggesting that procaspase-8 plays a role of a non-apoptotic modulator in VEGF-induced angiogenic signaling. These results suggest that TRAIL inhibits VEGF-induced angiogenesis by increasing caspase-8 activity and subsequently decreasing non-apoptotic signaling functions of procaspase-8, without inducing caspase-3 activation and endothelial cell cytotoxicity. These data indicate that caspase-8 may be used as an anti-angiogenic drug for solid tumors resistant to TRAIL and anti-tumor drugs.

Prevention of VEGF-mediated microvascular permeability by C-peptide in diabetic mice.

AIMS: Human C-peptide has a beneficial effect on the prevention of diabetic neuropathy, nephropathy, and vascular complications; however, its role in protection against increased vascular permeability in diabetes remains unclear. Our purpose was to explore the potential protective role of C-peptide against microvascular permeability mediated by vascular endothelial growth factor (VEGF)-induced reactive oxygen species (ROS) generation in diabetes. METHODS AND RESULTS: Generation of intracellular ROS, real-time changes in intracellular Ca(2+), ROS-dependent stress fibre formation, and the disassembly of the adherens junctions were studied by a confocal microscopy in human umbilical vein endothelial cells (HUVECs). VEGF-induced vascular leakage was investigated in the skin of diabetic mice using a Miles vascular permeability assay. Microvascular leakage in the retina of streptozotocin diabetic mice was investigated using a confocal microscopy after left ventricle injection of fluorescein isothiocyanate (FITC)-dextran. C-peptide inhibited the VEGF-induced ROS generation, stress fibre formation, disassembly of vascular endothelial cadherin, and endothelial permeability in HUVECs. Intradermal injection of C-peptide prevented VEGF-induced vascular leakage. Consistent with this, intravitreal injection of C-peptide prevented the extravasation of FITC-dextran in the retinas of diabetic mice, which was also prevented by anti-VEGF antibody and ROS scavengers in diabetic mice. Conclusions/interpretation C-peptide prevents VEGF-induced microvascular permeability by inhibiting ROS-mediated intracellular events in diabetic mice, suggesting that C-peptide replacement is a promising therapeutic strategy to prevent diabetic retinopathy.

C-peptide prevents hyperglycemia-induced endothelial apoptosis through inhibition of reactive oxygen species-mediated transglutaminase 2 activation.

C-peptide is a bioactive peptide with a potentially protective role in diabetes complications; however, its molecular mechanism of protection against cardiovascular damage caused by hyperglycemia-induced apoptosis remains unclear. We investigated the protective mechanism of C-peptide against hyperglycemia-induced apoptosis using human umbilical vein endothelial cells and streptozotocin diabetic mice. High glucose (33 mmol/L) induced apoptotic cell death in endothelial cells via sequential elevation of intracellular Ca(2+) and reactive oxygen species (ROS) as well as subsequent activation of transglutaminase 2 (TG2). C-peptide (1 nmol/L) prevented endothelial cell death by inhibiting protein kinase C- and NADPH oxidase-dependent intracellular ROS generation and by abolishing high glucose-induced TG2 activation, without affecting intracellular Ca(2+) levels. Consistently, in the aorta of streptozotocin diabetic mice, hyperglycemia stimulated transamidating activity and endothelial cell apoptosis that was inhibited by C-peptide replacement therapy (35 pmol/min/kg) using osmotic pumps (control and diabetes, n = 8; diabetes + C-peptide, n = 7). In addition, C-peptide prevented hyperglycemia-induced activation of transamidation activity and apoptosis in the heart and renal cortex of streptozotocin diabetic mice. Thus, C-peptide protects endothelial cells from hyperglycemia-induced apoptotic cell death by inhibiting intracellular ROS-mediated activation of TG2. Furthermore, TG2 may be a promising avenue of therapeutic investigation to treat diabetic vasculopathies.

Rapidly growing ovarian endometrioid adenocarcinoma involving the vagina: a case report.

OBJECTIVE: We present a rare case of a very rapidly growing stage IV ovarian endometrioid adenocarcinoma involving the uterine cervix and vagina without lymph node involvement. CASE REPORT: A 43-year-old woman visited the hospital with complaints of lower abdominal discomfort and vaginal bleeding over the previous 3 months. Serum levels of tumor marker CA 125 and SCC antigen (TA-4) were normal. On magnetic resonance imaging, a 7.9×9.7cm heterogeneous mass with intermediate signal intensity was observed in the posterior low body of the uterus. Two months ago, a computed tomography scan revealed an approximate 4.5×3.0cm heterogeneously enhanced subserosal mass with internal ill-defined hypodensities. A laparotomy, including a total abdominal hysterectomy with resection of the upper vagina, bilateral salpingo-oophorectomy, pelvic and para-aortic lymph node dissection, appendectomy, total omentectomy, and biopsy of rectal serosa was performed. A histological examination revealed poorly differentiated endometrioid ovarian adenocarcinoma with vaginal involvement. The patient had an uncomplicated post-operative course. After discharge, she completed six cycles of adjuvant chemotherapy with paclitaxel (175mg/m(2)) and carboplatin (300mg/m(2)) and has remained clinically disease-free until June 2010. CONCLUSION: Epithelial ovarian cancer may grow very rapidly. The frequent measurement of tumor size by ultrasonography may provide important information on detection in a subset of ovarian carcinomas that develop from preexisting, detectable lesions.

Correlation between preoperative serum levels of five biomarkers and relationships between these biomarkers and cancer stage in epithelial overian cancer.

OBJECTIVE: To examine the correlation among the preoperative serum levels of five biomarkers presumed to be useful for early detection of epithelial ovarian cancer and evaluate the relationships between serum levels of these five biomarkers and epithelial ovarian cancer stage. METHODS: We analyzed 56 newly diagnosed epithelial ovarian cancer patients. Preoperative serum levels of leptin, prolactin, osteopontin (OPN), insulin-like growth factor-II, and CA-125 were determined by ELISA. We also examined the correlation between the serum levels of the biomarkers and ovarian cancer stage. Significant differences in the mean serum levels of two proteins, leptin and CA-125, were observed between stage subsets. RESULTS: There was a significant negative correlation between prolactin and leptin and a significant positive correlation between prolactin and OPN. Of the five biomarkers, only the mean serum CA-125 level showed a significant positive correlation with cancer stage (Spearman rho=0.24, p<0.01). OPN showed a marginally significant positive correlation with stage (Spearman rho=0.14, p=0.07). CONCLUSION: We demonstrated the relationship between five biomarkers in epithelial ovarian cancer. These tumor markers may be useful in screening for ovarian cancer, in characterizing disease states, and in developing therapeutic interventions targeting these marker proteins. Large-scale studies that include potential confounding factors and modifiers are necessary to more accurately define the value of these novel biomarkers in ovarian cancer.

Experience of implementation of objective structured oral examination for ethical competence assessment.

PURPOSE: We developed an objective structured oral examination (OSOE) case to assess the medical ethics of students. The aim of this study was to assess the reliability of OSOE with generalizability theory. METHODS: One 10-minute OSOE that contained key questions was developed. The evaluation sheet consisted of 4 domains: moral sensitivity, moral reasoning, decision making, and attitude. The total number of items was 13. The numbers of checklist items and global rating items were 11 and 2, respectively. Items and key questions were validated by 6 professionals. Standardization of the raters and the pilot study was performed before the OSOE. Fifty-four third-year medical students participated in the OSOE. The OSOE was duplicated, and 2 professors assessed 1 student independently. Each station lasted 8 minutes and was followed by a 2-minute interval,during which raters completed the checklist forms. We analyzed the reliability of the OSOE with the GENOVA program. RESULTS: The reliability (generalizability coefficient) was 0.945, and the interrater agreement was 0.867. The type of item, checklist or global rating, was the largest variance component. The reliability of the checklist alone was 0.668 and that of the global rating alone was 0.363. CONCLUSION: The OSOE is reliable and can be used to assess ethics. More research should focus on achieving validity.

CT20126, a novel immunosuppressant, prevents collagen-induced arthritis through the down-regulation of inflammatory gene expression by inhibiting NF-kappaB activation.

The colchicine-derived CT20126 compound has recently been shown to exert an immune regulatory effect and prolong the survival of allograft skins. In this study, we explored the anti-inflammatory and anti-arthritic effects of CT20126 in vivo and in vitro as well as investigated its underlying action mechanism. CT20126 suppressed the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2, tumor necrosis factor-alpha, and interleukin-1beta as well as the production of nitric oxide and prostaglandin E(2) in lipopolysaccharide (LPS)-treated macrophages as well as LPS-administered mice. This drug also inhibited the production of nitric oxide, prostaglandin E(2), and the chemokines, RANTES, GROalpha, and ENA-78, in cytokine-stimulated human synoviocytes. CT20126 suppressed NF-kappaB activation and iNOS promoter activity, which correlated with its inhibitory effect on phosphorylation-dependent IkappaB kinase activation, IkappaB phosphorylation and degradation, and NF-kappaB nuclear translocation, in LPS-stimulated macrophages. This compound also inhibited LPS-induced NF-kappaB-inducing kinase (NIK) and Akt phosphorylation, which are upstream of NF-kappaB activation. Furthermore, CT20126 significantly decreased the incidence and severity of arthritis as well as inhibited the expression of inflammatory cytokines, chemokines, iNOS, and cyclooxygenase-2 in the paws of collagen-induced arthritic mice. These findings indicate that CT20126 exerts an anti-inflammatory effect through NF-kappaB-responsive inflammatory gene expression by inhibiting the NIK- and Akt-dependent canonical NF-kappaB pathway and can be used as a therapeutic agent for rheumatoid arthritis related to chronic inflammation.