CTCs have emerged as a potential source of clinical significance. But with numerous isolating systems currently available, the numbers of captured CTCs vary widely. At this point, CellSearch remains the only FDA-approved system with clinical significance whereby the results could be used to monitor patients with metastatic colon, breast, or prostate cancer. However, its inability to isolate CTCs from non-high risk prostate cancer patients or CTCs that are EpCAM-negative has led to criticism. In this study, we have shown that size-based filtration successfully isolates CTCs from patients with localized and metastatic prostate cancer. We have also shown that CTCs can be successfully isolated from low and intermediate risk groups. Additionally, clusters of CTCs were preserved and isolated in all localized risk groups and metastatic patients. Furthermore, we enumerated the isolated CTCs using automated and manual methods in low risk, intermediate risk, high risk, and metastatic prostate cancer. The automated and manual counts were comparable. Moreover, the amounts of clusters and the size of clusters correlated with the status and stage of prostate cancer. / October 2016

La présence synchrone de métastases hépatiques (MH) et carcinose péritonéale (CP)d'origine colorectale (CRC) est associée à une survie globale médiocre et est traditionnellement considérée comme une contre-indication à l’approche chirurgicale curative. Cependant, suite aux résultats encourageants après traitement chirurgicale, quelques séries ont rapporté une survie prolongée atteignant 3 ans chez des patients sélectionnés, ce qui suggère qu’un traitement chirurgicale curative est possible. À ce jour, en cas de chirurgie majeure hépatique et péritonéale associée, aucune stratégie thérapeutique n'a été établie, Nous avons postulé que la régénération hépatique après une résection hépatique pourrait favoriser la croissance de la CP. Nous avons construit un modèle animal immunnocompetent de CP limitée. L'objectif de l’étude était d'analyser les effets de l’hépatectomie majeure et de la régénération hépatique dans notre modèle murin de PC et le processus d'angiogenèse associé. En outre, nous avons analysée une cohorte prospective multicentrique de patients ayant eu une résection hépatique et une chirurgie cytoréductive avec HIPEC synchrone. L'objectif de cette étude était d'évaluer les outcomes et identifier les facteurs pronostiques afin d'optimiser la sélection des candidats au traitement chirurgical et de déterminer la stratégie chirurgicale optimale. / The synchronous presence of liver metastases (LM) and peritoneal carcinomatosis (PC)from colorectal cancer (CRC) is associated with poor outcome and is traditionally considered acontraindication to any surgical approach. However, few series reported a prolonged survival aftersurgical management, reaching 3 years in selected patients thus suggesting that a curative surgicalmanagement may be possible. To date, no standard management pathway has been established,especially if a major liver and peritoneal surgery has to be performed. We postulated that liverregeneration after liver resection could promote PC growth. We constructed an immunocompetentanimal model of limited PC. The objective of our study was to analyze the effects of major LR andliver regeneration after hepatectomy on peritoneal carcinomatosis growth and the associatedangiogenesis process. Furthermore, we have analyzed a prospective international cohort of patientsundergoing synchronous liver resection and cytoreductive surgery with HIPEC. The aim of this studywas to describe the outcomes, to identify variables potentially related to poor outcome, in order toestablish future guideline for the management of these patients, to optimize the selection of candidatesfor surgical treatment and determine the best surgical strategy.

Vasculogenic cell-based therapy combined with tissue engineering is a promising revascularization strategy for patients with hibernating myocardium, a common clinical condition. We used a clinically relevant swine model of hibernating myocardium to examine the benefits of biopolymer-supported delivery of circulating angiogenic cells (CACs) in this context. Twenty-five swine underwent placement of an ameroid constrictor on the left circumflex artery (LCx). After 2 weeks, positron emission tomography measures of myocardial blood flow (MBF) and myocardial flow reserve (MFR) were reduced in the affected region (both p<0.001). Hibernation (mismatch) was specific to the LCx territory. Swine were randomized to receive intramyocardial injections of PBS control (n=10), CACs (n=8), or CACs + a collagen-based matrix (n=7). At follow-up, stress MBF and MFR were increased only in the cells+matrix group (p<0.01), and mismatch was lower in the cells+matrix treated animals (p=0.02) compared to controls. Similar results were found using microsphere-measured MBF. Wall motion abnormalities and ejection fraction improved only in the cells+matrix group. This preclinical swine model demonstrated ischemia and hibernation, which was improved by the combined delivery of CACs and a collagen-based matrix. To our knowledge, this is the first demonstration of the mechanisms and effects of combining progenitor cells and biopolymers in the setting of myocardial hibernation, a common clinical condition in patients with advanced coronary artery disease.

Early diagnosis represents an effective way to improve patient prognosis in cancer. New opportunities for cancer diagnosis and screening may arise from identification of cancer-specific epigenetic alterations in the cell-free circulating DNA (cirDNA). This study investigated biomarkers at the level of DNA methylation in the plasma cirDNA of individuals affected with prostate cancer or colorectal cancer. A methylation-sensitive restriction enzyme-based method was used to enrich methylated DNA fractions, which were interrogated on CpG island and human genome tiling microarrays. A number of genes and non-coding loci exhibited differential methylation between prostate cancer patients and controls. The candidate loci identified from these microarray experiments underwent verification by bisulfite modification coupled with pyrosequencing. Our results suggest that microarray-based studies of DNA methylation in the cirDNA can be a promising avenue for the identification of epigenetic biomarkers in cancer.

Early diagnosis represents an effective way to improve patient prognosis in cancer. New opportunities for cancer diagnosis and screening may arise from identification of cancer-specific epigenetic alterations in the cell-free circulating DNA (cirDNA). This study investigated biomarkers at the level of DNA methylation in the plasma cirDNA of individuals affected with prostate cancer or colorectal cancer. A methylation-sensitive restriction enzyme-based method was used to enrich methylated DNA fractions, which were interrogated on CpG island and human genome tiling microarrays. A number of genes and non-coding loci exhibited differential methylation between prostate cancer patients and controls. The candidate loci identified from these microarray experiments underwent verification by bisulfite modification coupled with pyrosequencing. Our results suggest that microarray-based studies of DNA methylation in the cirDNA can be a promising avenue for the identification of epigenetic biomarkers in cancer.

Vasculogenic cell-based therapy combined with tissue engineering is a promising revascularization strategy for patients with hibernating myocardium, a common clinical condition. We used a clinically relevant swine model of hibernating myocardium to examine the benefits of biopolymer-supported delivery of circulating angiogenic cells (CACs) in this context. Twenty-five swine underwent placement of an ameroid constrictor on the left circumflex artery (LCx). After 2 weeks, positron emission tomography measures of myocardial blood flow (MBF) and myocardial flow reserve (MFR) were reduced in the affected region (both p<0.001). Hibernation (mismatch) was specific to the LCx territory. Swine were randomized to receive intramyocardial injections of PBS control (n=10), CACs (n=8), or CACs + a collagen-based matrix (n=7). At follow-up, stress MBF and MFR were increased only in the cells+matrix group (p<0.01), and mismatch was lower in the cells+matrix treated animals (p=0.02) compared to controls. Similar results were found using microsphere-measured MBF. Wall motion abnormalities and ejection fraction improved only in the cells+matrix group. This preclinical swine model demonstrated ischemia and hibernation, which was improved by the combined delivery of CACs and a collagen-based matrix. To our knowledge, this is the first demonstration of the mechanisms and effects of combining progenitor cells and biopolymers in the setting of myocardial hibernation, a common clinical condition in patients with advanced coronary artery disease.

Circulating tumor cells (CTCs) are the cells that are shed from a primary tumor into the vasculature and circulate in the bloodstream. CTCs may trigger cancer metastasis, which leads to most cancer-related deaths. CTCs are widely studied due to their value in cancer diagnosis, prognosis, and oncology studies. The major challenges with CTCs lie in their extremely low concentration in blood, thus requiring an effective enriching system to enable downstream analyses. The immunomagnetic assay has proved to be a promising CTC detection tool with high sensitivity and throughput. Key factors related to the immunomagnetic assay include the capture rate, which indicates the sensitivity, and distributions of target cells after capture, which impact the cell integrity and other biological properties. In this dissertation, we build a sedimentation model, a partial viscosity model, and a cell-tracking model to address the principle of the immunomagnetic cell separation. We examine the channel orientations and determine the favorable inverted condition. In addition, we develop a micromagnet approach to modulate the in-channel magnetic field toward enhanced cell detection and distribution. Through numerical studies, we calculate the magnetic field generated by the thin-film micromagnets, determine its effective ranges, and demonstrate its value in optimizing cell distribution. In the experimental demonstration, we present two types of micromagnets based on e-beam Ni deposition and inkjet printing technology, respectively. In the screening experiments, the Ni micromagnet integrated system achieves over 97% capture rate. It shows a 14% increase in capture rate, and a 14% improvement in distribution uniformity compared with plain slides. We also successfully isolate CTCs from metastatic cancer patients with the micromagnet assay. The inkjet-printed patterns yield a similarly high capture rate of 103%. With the pixel permanent magnet array, the inkjet patterns further increase the distribution uniformity for 20%. The proposed models lay the theoretical foundations for future modification of the immunomagnetic assay, and the micromagnet-integrated system provides a promising tool for translational applications in cancer diagnose and clinical cancer management. / text

The attachment and detachment of circulating tumor cells in a functionalized microchannel under hydrodynamic loading have been studied. For the cell attachment experiments, EpCAM antibodies are immobilized on the microchannel surface to capture either PC3N prostate or MDA-MB-231 breast cancer cells from homogeneous cell suspensions. Using the same protocol, N-Cadherin antibodies are immoblilzed and used to study the detachment of target cancer cells captured in the microchannels.A critical flow rate Qc has been identified to characterize the kinetics of cell capture in a functionalized microchannel. Approaching one limit, when the receptor-ligand interaction dominates, more than 90% of moving cells can be captured and a sharp peak is observed in the spatial distribution of the captured cells. Approaching another limit, when hydrodynamic loading dominates, almost all cells cannot be captured in the channel. Between these two limits, there is a transition region in which both capture efficiency and cell distribution are sensitive to the flow parameters. Proper characteristic time and length scales have been identified to describe the cell spatial distribution using a log-normal statistical model. The kinetic details of cell capture are determined by the competition between the flow rate and the ligand-receptor association/dissociation rates.Additionally, the attachment dynamics of circulating tumor cells in a bio-functionalized microchannel under hydrodynamic loading has been explored. The target cells initially role along the microchannel with fluctuating velocity prior to firm adhesion. When a successful bond is established, the cancer cells require a certain length to come to a complete stop; this stopping length is found to depend linearly on the applied hydrodynamic flow rate. The force balance in the vertical cross stream direction is dominated by the gravitational force; as a result, all cells loaded into a microchannel intimately contact the functionalized channel bottom surface within a short time. The streamwise horizontal motion of the cells on the surface is dominated by the balance between the shear flow hydrodynamic loading and the receptor-ligand binding interaction. A linear spring element is incorporated in the physical model to represent the dynamics of a cancer cell captured by immobilized antibodies. Featuring a mobility matrix, a proposed theoretical model is utilized to estimate the binding and hydrodynamic forces acting on the cell in a microchannel. Inserting certain fitting parameters, the time evolution of a stopping cell is successfully predicted by a simplified exponential function.The mechanical response of a captured cancer cell to a hydrodynamic flow field is investigated and, in particular, the effect of flow acceleration is examined. The observed cell deformation is dramatic under low acceleration, but is negligible under high acceleration. Consequently, the detachment of captured cells depends on both flow rate and flow acceleration. The flow rate required for cell detachment is a random variable that can be described by a log-normal distribution. Two flow acceleration limits have been identified for proper scaling of the flow rate required to detach captured cells. A time constant on the order of 1min for the mechanical response of a captured cell has been identified for scaling the flow acceleration. Based on these acceleration limits and the time constant, an exponential-like empirical model is proposed to predict the flow rate required for cell detachment as a function of flow acceleration.

Biomass, as a renewable energy resource, can be utilized to generate chemicals, heat, and electricity. Compared with biomass combustion, biomass gasification is more eco-friendly because it generates less amount of green gas (CO2) and other polluting gases (NOx and SO2). This research is focused on biomass gasification using a circulating fluidized bed. In the gasifier, fully fluidized biomass particles react with water vapor and air to generate syngas (CO and H2). A comprehensive model, consisting of three modules, hydrodynamics, mass transfer and energy transfer modules, is built to simulate this process using ANSYS Fluent software and C programming language. In the hydrodynamics module, the k-epsilon turbulence equations are coupled with the fluctuating energy equation to simulate gas-particle interaction in the turbulent flows occurring in the riser. In the mass transfer and energy transfer modules, heat transfer and mass transfer in turbulent flows are simulated to solve for the profiles of temperature and species concentration in the gasifier. The impacts of thermal radiation, water gas shift reaction (WGS), equivalence ratio (ER), and char combustion product distribution coefficient are also investigated to gain deeper understanding of biomass gasification process.

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