Quotients of incidence geometries

We develop a theory for quotients of geometries and obtain sufficient conditions for the quotient of a geometry to be a geometry. These conditions are compared with earlier work on quotients, in particular by Pasini and Tits. We also explore geometric properties such as connectivity, firmness and transitivity conditions to determine when they are preserved under the quotienting operation. We show that the class of coset pregeometries, which contains all flag-transitive geometries, is closed under an appropriate quotienting operation.Comment: 26 pages, 5 figure

A non-invasive approach to monitor chronic lymphocytic leukemia engraftment in a xenograft mouse model using ultra-small superparamagnetic iron oxide-magnetic resonance imaging (USPIO-MRI)

Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia among adults. Despite its indolent nature, CLL remains an incurable disease. Herein we aimed to monitor CLL disease engraftment and,progression/regression in a xenograft CLL mouse model using ultra-small superparamagnetic iron oxide-magnetic resonance imaging (USPIO-MRI). Spleen contrast enhancement, quantified as percentage change in signal intensity upon USPIO administration, demonstrated a difference due to a reduced USPIO uptake, in the spleens of mice injected with CLL cells (NSG-CLL, n=71) compared to controls (NSG-CTR, n=17). These differences were statistically significant both after 2 and 4weeks from CLL cells injection. In addition comparison of mice treated with rituximab with untreated controls for changes in spleen iron uptake confirmed that it is possible to monitor treatment efficacy in this mouse model of CLL using USPIO-enhanced MRI. Further applications could include the preclinical in vivo monitoring of new therapies and the clinical evaluation of CLL patients

Staging of Hilar cholangiocarcinoma with Ultrasound

The preoperative assessment of the extent of biliary and vascular involvement by hilar cholangiocarcinoma is clinically important because resectability may be limited by tumor extension along the bile ducts into the hepatic parenchyma or to the adjacent hilar vessels. Thirty-five patients with hilar cholangiocarcinoma were studied with ultrasound, and the results were compared with operative findings and other diagnostic modalities. The level of intrahepatic biliary obstruction was determined in 100% of patients with ductal ectasia, and a tumor mass was shown in 37.1%. Imaging and Doppler ultrasound proved accurate in detecting the neoplastic involvement of the portal vein. Both correctly diagnosed portal occlusion and wall infiltration in 4 of 4 and 15 of 18 (83%) patients, respectively, without any false-positives. On the contrary, imaging ultrasound had poor sensitivity in detecting infiltration of the hepatic artery (43%) and metastases in regional lymph nodes (37%), liver (66%), and peritoneum (33%). In conclusion, ultrasound may be valuable in the preoperative staging of hilar cholangiocarcinoma, specially in predicting ductal and portal involvement