Alien Registration- Beaulieu, Emile (Allagash, Aroostook County)

https://digitalmaine.com/alien_docs/32783/thumbnail.jp

Wide-Field Spatial Frequency Domain Imaging, Diffuse Reflectance and Endogenous Fluorescence Spectroscopy System for Quantitative Tissue Biomarkers in Radical Prostatectomy Specimens

Résumé La seule approche chirurgicale présentement utilisée pour le traitement du cancer de la prostate est le retrait complet de l’organe ; la prostatectomie radicale. Similairement à d’autres procédures de résection du cancer, une importante mesure du succès de l’opération est le degré auquel le cancer a été retiré du patient, car les chances de récurrence sont augmentées par la présence de cancer résiduel. Puisque la prostate est entourée de structures génito-urinaires importantes relativement à la qualité de vie du patient, retirer l’entièreté de la prostate tout en évitant d’impacter les structures avoisinantes est une tâche complexe. Par ailleurs, la navigation chirurgicale en prostate nécessite de grandes améliorations étant donné l’inexistence de modalités d’imagerie compatibles pour des méthodes de recalage avec ce cancer, et la faible précision et le peu d’informations spatiales fournies par les méthodes diagnostiques actuelles. Il y a un réel besoin de nouveaux outils permettant la différenciation de tissus lors de la prostatectomie radicale et ainsi la résection ciblée des tissus. La fluorescence endogène est une technique d’imagerie donnant accès à des informations moléculaires sur un échantillon et a été utilisée dans maintes applications pour la caractérisation de tissus. La méthode a été appliquée sur les tissus prostatiques avec des sondes ponctuelles, mais n’a pas trouvé d’usage en champ de vue macroscopique. Cependant, sans traitement, la fluorescence n’est pas un reflet direct du contenu moléculaire, puisqu’elle est en compétition avec d’autres processus comme l’absorption et la diffusion élastique. À cet effet, des méthodes corrigeant l’absorption et la diffusion ont été élaborées à partir de mesures de réflectance diffuse. Celles-ci étaient limitées aux géométries ponctuelles jusqu’au développement de l’imagerie dans le domaine des fréquences spatiales (spatial frequency domain imaging, SFDI), qui permet la reconstruction des coefficients d’absorption (ua) et de diffusion (u0s) en grand-champ. Toutefois, les techniques de correction de fluorescence dérivées du SFDI n’ont été appliquées qu’à des agents de fluorescence externes. Ainsi, ce projet présente un système multimodal grand-champ combinant fluorescence endogène, réflectance diffuse et SFDI pour obtenir des informations moléculaires quantitatives sur des spécimens de prostatectomie radicale. Premièrement, les modalités de fluorescence, réflectance et SFDI ont été intégrées dans un système d’imagerie avec des spécifications adaptées aux échantillons de prostates ; soit un champ de vue de 5.5 x 5.5 cm, résolution spatiale de 70 um et profondeur de champ de 1.5 cm.----------Abstract The only current surgical approach to the treatment of prostate cancer is radical prostatectomy, which enforces the complete resection of the organ. Similarly to other forms of cancer resection, the degree of success of the surgery is directly influenced by the completeness of cancer removal, as residual cancer increases the risks of recurrence. Because the prostate is close to critical genitourinary structures with a high impact on patient quality-of-life, achieving complete resection with a minimum amount of side-effects on the surrounding tissues is a challenging task. Surgical guidance in the prostate requires vital improvement due to the lack of proper co-registration imaging methods and inaccurate diagnostic techniques which give very limited spatial information. Consequently, there is a need for new tools to characterize tissue during radical prostatectomy and guide resection. Endogenous fluorescence provides molecular information from the tissue and thus has found use for tissue characterization in multiple applications. Although the technique was applied to prostate tissue in point probes, it has never been explored in macroscopic geometries. Fluorescence also competes with other optical events like absorption and elastic scattering, which makes it indirectly related to tissue molecular content. Optical properties derived from diffuse reflectance measurements can be used to correct these optical events and compute quantified fluorescence. Such correction models were limited to point geometries until the development of the spatial-frequency domain imaging (SFDI) technique, which allowed the extraction of absorption (ua) and scattering (u0s) coefficients in wide-field configurations. However, SFDIbased quantification has only been applied to external fluorescence agents. This project presents the development of a wide-field multimodal system that combines endogenous fluorescence, diffuse reflectance, and SFDI to obtain quantitative molecular information from radical prostatectomy samples. At first fluorescence, reflectance and SFDI were integrated into a single system with a field of view of 5.5 x 5.5 cm, spatial resolution of 70 um and depth of field of 1.5 cm adapted to the prostate samples. Calibration processes and acquisition parameters were determined with experiments on optical phantoms. SFDI reconstruction was accurate within 5.2% and 4.4% for absorption and scattering respectively; performances similar to other systems in the literature. Quantification of fluorescence also resulted in a significant increase in the correlation of measured intensity to fluorophore concentration

Wide-field optical spectroscopy system integrating reflectance and spatial frequency domain imaging to measure attenuation-corrected intrinsic tissue fluorescence in radical prostatectomy specimens

The development of a multimodal optical imaging system is presented that integrates endogenous fluorescence and diffuse reflectance spectroscopy with single-wavelength spatial frequency domain imaging (SFDI) and surface profilometry. The system images specimens at visible wavelengths with a spatial resolution of 70 microm, a field of view of 25 cm(2) and a depth of field of approximately 1.5 cm. The results of phantom experiments are presented demonstrating the system retrieves absorption and reduced scattering coefficient maps using SFDI with <6% reconstruction errors. A phase-shifting profilometry technique is implemented and the resulting 3-D surface used to compute a geometric correction ensuring optical properties reconstruction errors are maintained to <6% in curved media with height variations <20 mm. Combining SFDI-computed optical properties with data from diffuse reflectance spectra is shown to correct fluorescence using a model based on light transport in tissue theory. The system is used to image a human prostate, demonstrating its ability to distinguish prostatic tissue (anterior stroma, hyperplasia, peripheral zone) from extra-prostatic tissue (urethra, ejaculatory ducts, peri-prostatic tissue). These techniques could be integrated in robotic-assisted surgical systems to enhance information provided to surgeons and improve procedural accuracy by minimizing the risk of damage to extra-prostatic tissue during radical prostatectomy procedures and eventually detect residual cancer

Oxidative Stress and Mitochondrial Functions in the Intestinal Caco-2/15 Cell Line

Although mitochondrial dysfunction and oxidative stress are central mechanisms in various pathological conditions, they have not been extensively studied in the gastrointestinal tract, which is known to be constantly exposed to luminal oxidants from ingested foods. Key among these is the simultaneous consumption of iron salts and ascorbic acid, which can cause oxidative damage to biomolecules.The objective of the present work was to evaluate how iron-ascorbate (FE/ASC)-mediated lipid peroxidation affects mitochondrion functioning in Caco-2/15 cells. Our results show that treatment of Caco-2/15 cells with FE/ASC (0.2 mM/2 mM) (1) increased malondialdehyde levels assessed by HPLC; (2) reduced ATP production noted by luminescence assay; (3) provoked dysregulation of mitochondrial calcium homeostasis as evidenced by confocal fluorescence microscopy; (4) upregulated the protein expression of cytochrome C and apoptotic inducing factor, indicating exaggerated apoptosis; (5) affected mitochondrial respiratory chain complexes I, II, III and IV; (6) elicited mtDNA lesions as illustrated by the raised levels of 8-OHdG; (7) lowered DNA glycosylase, one of the first lines of defense against 8-OHdG mutagenicity; and (8) altered the gene expression and protein mass of mitochondrial transcription factors (mtTFA, mtTFB1, mtTFB2) without any effects on RNA Polymerase. The presence of the powerful antioxidant BHT (50 microM) prevented the occurrence of oxidative stress and most of the mitochondrial abnormalities.Collectively, our findings indicate that acute exposure of Caco-2/15 cells to FE/ASC-catalyzed peroxidation produces harmful effects on mitochondrial functions and DNA integrity, which are abrogated by the powerful exogenous BHT antioxidant. Functional derangements of mitochondria may have implications in oxidative stress-related disorders such as inflammatory bowel diseases

Alien Registration- Beaulieu, Emile (Allagash, Aroostook County)

https://digitalmaine.com/alien_docs/32783/thumbnail.jp