This thesis describes experimental work performed (1998-2001) during the author's involvement with the Brachytherapy group at the Peter MacCallum Cancer Centre (PMCC), where he was employed by its Department of Physical Sciences and subsequent modeling and analytical studies. When PMCC added HDR brachytherapy to its radiation therapy practice, an existing operating suite was considered the ideal location for such procedures to be carried out. The integration of brachytherapy into the theatre environment was considered logical due to the relatively invasive nature of brachytherapy techniques and the availability of medical equipment. This thesis contains the detailed study of three key Research Questions involved in clinical aspects relating to quality assurance of an HDR brachytherapy practice. An investigative chapter is dedicated to the pursuit of each of the Research Questions. The first question asked… Is the novel approach to using modular shielding combined with time and distance constraints adequately optimized during HDR brachytherapy? In order to establish optimal clinical practices, this project evaluates the effectiveness of additional shielding added to the modular shielding system without modification of the previously determined time and distance constraints for PMCC staff, other patients, and member of the public. The DOSXYZnrc user code for the EGSnrc Monte Carlo radiation transport code has been used to model exposure pathways to strategic locations used for measurement in and around the operating theatre suite. Modeling allowed exposure pathways to various areas with the facility to be tested without the need to use real sources. The second Research Question asked… How well is dose anisotropy characterized in the near field range of the clinic's HDR 192Ir source? This study experimentally investigated the anisotropy of dose around a 192Ir HDR source in a water phantom using MOSFETs as relative dosimeters. In addition, modeling using the DOSRZnrc user code for the EGSnrc Monte Carlo radiation transport code was performed to provide a complete dose distribution consistent with the MOSFET measurements. Measurements performed for radial distances from 5 to 30 mm extend the range of measurements to 5 mm which has not been previously reported for this source construction. The third Research Question is aimed at the patient level. Is the dose delivered to in vivo dosimeters, located within critical anatomical structures near the prostate, within acceptable clinical tolerance for a large group of HDR prostate patients? An in vivo dosimetry technique employing TLDs to experimentally measure doses delivered to the urethra and rectum during HDR prostate brachytherapy was investigated. Urethral and rectal in vivo measurements for 56 patients have been performed in the initial fraction of four-fraction brachytherapy boost. In the absence of comparable in vivo data, the following local corrective action level was initially proposed: more than 50% of the prostatic urethra receiving a dose 10% beyond the urethral tolerance. The level for investigative action is considered from the analyses of dose differences between measured data and TPS calculation.

Le cancer de la prostate est la seconde cause de mortalité par cancer chez l'homme. Actuellement, les traitements hormonaux visent à diminuer le taux d'androgènes actifs. Malheureusement, avec le temps, les patients développent un cancer androgènes dont l'issue est fatale. Le calcium (Ca2+), second messager ubiquitaire, est impliqué dans de nombreux processus tels que l'apoptose ou la prolifération. Le Réticulum Endoplasmique (RE) est un acteur essentiel de la signalisation calcique. Ainsi, l'étude de canaux calciques réticulaires est fondamentale dans le développement de nouvelles stratégies thérapeutiques. Les travaux effectués ont permis d'identifier deux nouvelles protéines sur le RE : le translocon et le canal TRPM8 (Transient Receptor Potential Melastatin 8). Ces deux protéines seraient des éléments majeurs de la signalisation calcique en régulant la concentration de Ca2+ du RE. Par ailleurs, l'étude de l'évolution de la signature calcique au cours de la cancérogenèse prostatique a permis de mettre en évidence qu'Orai1 (identifié ici comme étant la protéine responsable de l'Entrée Capacitive de Ca2+) est moins exprimée dans les cancers les plus agressifs. A l'opposé, TRPV6 (Transient receptor potential Vanilloid 6), canal calcique impliqué dans l'entrée constitutive de Ca2+, est surexprimé dans des stades avancés de cancer. Ainsi, les variations d'expression de ces protéines seraient responsables respectivement d'un défaut d'apoptose ou d'une augmentation de la prolifération des cellules cancéreuses prostatiques androgéno-indépendantes. Ceci permettrait d'expliquer l'évolution du cancer de la prostate vers des stades plus agressifs.

Le principal objectif de cette thèse est la conception et la production d'outils à destination des radiologues pour la délinéation des organes à risque dans le cadre du traitement par radiothérapie du cancer de la prostate. Les images passées entrées sont des images CT. Elles sont d'abord placées dans un repère commun à l'aide d'un recalage log-euclidien concentré sur les structures osseuses du pubis. Une suite progressive de traitements est ensuite appliquée: dans un premier temps, la vessie est segmentée, puis la prostate est ensuite localisée paralellement à la vessie, pour finir avec l'intégration de la délinéation du rectum. Compte tenu de l'hétérogénéité des images de la base de données sur laquelle nous avons travaillé, notre contribution principale est la flexibilité. La vessie est une structure à forte variabilité en termes de forme et d'intensité, notamment à cause du degré de remplissage et la présence ou l'absence d'un produit de contraste. La méthode proposée s'adapte non seulement aux formes très différentes des vessies de notre base de donnée, mais aussi au degré de replissage donnant lieu, dans le cas ou un produit de contraste a été administré, une h'etérogénéité notable dans la structure à segmenter. Le contraste de la prostate avec les tissus environnants est quasi-nul; son interface avec la vessie est souvent très difficile à distinguer, même par les experts médicaux. L'incorporation d'informations anatomiques sur la forme et d'informations images, couplée à une nouvelle contrainte d'interaction entre deux maillages, permet d'obtenir une bonne segmentation de la prostate et d'éliminer les ambiguités au niveau de l'interface entre les deux structures. L'incorportation du rectum est l'étape la plus délicate: les différences entre les protocoles d'acquisition de la base de données utilisée interdisent toute modélisation de l'intérieur du rectum: présence de matières fécales, insuflation d'air, présence d'un produit de contraste, présence d'une sonde etc. Les hypotheses faites sur les tissus connexes au rectum ainsi qu'une nouvelle contrainte tubulaire couplée a une pré-segmentation du squelette du rectum permettent d'obtenir un résultat probant. La chaîne de traitement qui a conduit a l'élaboration de cette thèse est en cours d'incorporation dans le logiciel Isogray produit par DOSIsoft, ce qui permet une validation plus approfondie dans des conditions cliniques.

<p> In the work of this doctoral dissertation a new resonator sensor technique, first presented in 1989, has been further developed and evaluated with focus on technical characteristics and applications within the medical field.</p><p> In a first part a catheter-type tactile sensor using the resonator sensor technique was evaluated in a silicone model and applied to human prostate in vitro. The main finding was that different histological compositions of prostate tissue correlated with the frequency shift, .fS, of the resonator sensor and that the common property was the hardness of the tissue. The results indicated that hardness of the prostate tissue, and maybe hardness of human tissue in general, can be expressed according to a cone penetration standard (DIN ISO 2137) and that the hardness can be measured with this tactile sensor system. The tissue hardness application for the resonator sensor technique has to be further developed and evaluated in a larger study. The study also produced results that has led to the basic understanding of the resonator sensor system. One important result was that .fS of the sensor system was related to the contact area between sensor and sample. This indicated that the resonance sensor could be used for contact area measurement.</p><p> In a second part, containing three studies, the area-sensing capability from the first study was utilised in the development and evaluation of the applanation resonator sensor (ARS) for measurement of intraocular pressure (IOP). For the purpose of evaluating IOP-tonometers, an in vitro pig-eye model was developed, and it was shown that a saline column connected to the vitreous chamber could be used successfully to induce variations in IOP.</p><p> A ARS sensor with a flat contact surface was applied onto the cornea with constant force and .fS was measured. A mathematical model based on the Imbert-Fick law and the assumption that .fS was linearly related to contact area was proposed and verified with a convincing result. IOP measured with the ARS correlated well (r=0.92, n=360) with the IOP elicited by a saline column.</p><p> The ARS in a constant-force arrangement was evaluated on healthy human subjects in vivo. The results verified the sensor principle but revealed a nonnegligible source of error in off-centre positioning between the sensor and cornea. The sensor probe was redesigned and evaluated in the in vitro model. The new probe, with a spherical contact surface against the eye reduced the sensitivity to off-centre positioning. It was also shown that a .fS normalisation procedure could reduce the between-eye differences.</p><p> The ARS method for IOP measurement was further developed using combined continuous force and area measurement during the dynamic phase when the sensor initially contacts the cornea. A force sensor was included with the resonator sensor in one probe. Evaluation was performed with the in vitro pig-eye model. The hypothesis was that the IOP could be deduced from the differential change of force and area during that phase. The study showed good accuracy and good reproducibility with a correlation of r=0.994 (n=414) between measured pressure in the vitreous chamber and IOP according to the ARS. Measurement time was short, 77 ms after initial contact. Problems with inter-eye differences and low resolution at high pressures were reduced. The ARS method is the first to combine simultaneous, continuous sampling of both parameters included in the applanation principle. Consequently, there is a potential for reducing errors in the clinical IOP tonometry. </p>

<p>The aims of the thesis were to</p><p>• explore whether radical prostatectomy is beneficial compared with watchful waiting in survival and disease progression</p><p>• find possible effect modifiers</p><p>• evaluate a protocol of multiple biopsies and investigate if men with previous benign prostate biopsies are a group at risk for later prostate cancer</p><p>• inquire into patients’ and clinicians’ experiences of randomization in order to find out what made this study possible to conduct, and thereby contribute to improve randomization in the future</p><p>The background material was a large randomized clinical trial, the Scandinavian Prostatic Cancer Group Study Number 4, or SPCG-4, which was open for inclusion from February 1989 through December 1999. It comprised 695 men in Sweden, Finland and Iceland who had localized prostate cancer and were randomized to either radical prostatectomy or watchful waiting. </p><p>After a mean follow-up time of 6.2 years the first analyses, according to intention-to-treat, showed that radical prostatectomy reduced disease specific mortality, risk of metastases and risk of local progression but did not statistically significantly reduce overall mortality. </p><p>The second analyses confirmed our earlier findings and furthermore, at ten years, radical prostatectomy also statistically significantly reduced overall mortality. Age appeared as an independent effect modifier that will be further investigated.</p><p>A total of 547 men, with a suspicion of prostate cancer that had undergone multiple biopsies, and whose biopsies had benign histology were later compared with the background population to evaluate whether they were a group at risk of developing prostate cancer. Within six years of follow-up, there was no increased risk of prostate cancer.</p><p>Patients as well as clinicians used individual strategies to cope with the situation. The randomizing clinician has to understand the patient’s strategy and his expectations in order to individualize the information accordingly.</p>

<p>Prostasomes are submicron-sized, membrane-bound organelles produced by the epithelial cells of the prostate and normally found in the secretion in the gland ducts. Their physiological role is in the promotion of sperm-function in human reproduction. This thesis contains four papers dealing with the production of prostasomes and some possible applications in clinical urology of the prostasome. </p><p>Paper I and II provided an ultrastructural description of the synthesis, storage and secretion of prostasomes in benign as well as in malignant tissue. Most notable were the extracellular appearances of prostasomes in metastatic lesions whereby the prostasomes become exposed to the immune system of the patient. This supported findings in earlier studies in which patients with advanced prostate cancer had elevated levels of anti-prostasome antibodies. The results of paper III reinforced the view of the prostate-unique origin of the prostasome. In particular, there were no indications in SDS-PAGE patterns or flow-cytometric studies of material from seminal vesicle secretion that it contained components that could be associated with a production of prostasomes. </p><p>Some possible clinical functions of the prostasomes were investigated in paper IV. Exposure of prostasomes to the immune system through mechanical and thermal trauma to the prostate did not induce an evident formation of anti-prostasome autoantibodies. Furthermore, the serum levels of anti-prostasome antibodies registered by assays with preparations of prostasomes from seminal plasma as antigen did not correlate with existing prostate cancer. Seminal prostasomes seemed not to function as substitute markers for prostate cancer in the test kit used. A possible explanation could be underestimated differences in antigen properties between seminal or prostate gland-derived prostasomes and prostasomes from tumor tissue.</p>

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 87-93).

1,25-(OH)2 vitamin D3 inhibits cell proliferation of a variety of cancers including prostate. In the human prostate cancer cell line LNCaP, 1,25-(OH)2 vitamin D3-mediated growth inhibition is attributed to cell cycle G1 accumulation which correlates with a robust decrease of cyclin-dependent kinase 2 (CDK2) activity and pronounced relocalization of CDK2 into the cytoplasm. Nuclear targeting CDK2 blocks the 1,25-(OH)2 vitamin D3-mediated growth inhibition and cell cycle G1 accumulation. Further, the nuclear targeted CDK2 blocks 1,25-(OH)2 vitamin D3-mediated inhibition of CDK2 activity and nuclear exclusion in LNCaP cells. Therefore, CDK2 cytoplasmic relocalization is the key mechanism for 1,25-(OH)2 vitamin D3 effects. Since cyclin E is important for CDK2 nuclear localization and activation, 1,25-(OH)2 vitamin D3 may exert its effects through regulation of cyclin E. Cyclin E but not a cyclin E mutant deficient in CDK2 binding reverses 1,25-(OH)2 vitamin D3-mediated antiproliferation which suggests the involvement of cyclin E as a mechanism. However, the studies showed no effects of 1,25-(OH)2 vitamin D3 on cyclin E levels, intracellular localization or binding to CDK2. In order to develop a model for studying 1,25-(OH)2 vitamin D3-mediated antiproliferative effects, LNCaP vitD.R cell line, a vitamin D resistant LNCaP derivative, was generated by continuously culturing of LNCaP cells in medium supplemented with 10 nM 1,25-(OH)2 vitamin D3 for over 9 months. The initial characterization of this cell line showed complete resistance to 1,25-(OH)2 vitamin D3-mediated effects. Analysis of vitamin D regulation of VDR target gene expression revealed that vitamin D resistance in LNCaP vitD.R cells was not due to deregulation of VDR signaling. HDAC inhibitor Trichostatin A (TSA) did not confer sensitivity of LNCaP vitD.R cells to vitamin D treatment suggested the resistance to 1,25(OH)2 vitamin D3 effect of LNCaP vitD.R cells is not due to histone deacetylase remodeling of the chromatin structure which leads to inhibition of gene transcription. While the partial sensitization of LNCaP vitD.R cells to 1,25(OH)2 vitamin D3 effect by demethylation reagent 5-Aza-2¡¯-deoxycytidine treatment suggested a set of genes involved in 1,25(OH)2 vitamin D3-mediated antiproliferative effects is silenced via hypermethylation in LNCaP vitD.R cells. These results suggested LNCaP vitD. R cell line is a useful tool and further studies to elucidate the genes involved in this effect will help uncover the mechanisms of 1,25(OH)2 vitamin D3-mediated antiproliferative effects.

Research on aging indicates that older adults do not, as a group, report decreased health-related quality of life (HRQOL) despite age-related declines in physical health status. Several cognitive adaptation strategies have been suggested to underlie HRQOL stability in this population. Studies of older cancer patients nevertheless show substantial variance in post-treatment HRQOL outcomes, although cognitive mechanisms for individual differences have received little attention. The current study expanded on a developmental adaptation of self-regulation theory in which aging influences both self-vulnerability and perceptions of disease. A model was tested in which older age was hypothesized to predict better HRQOL via less severe illness perceptions in men treated for localized (Stage I and II) PC. Results indicated that age was not directly associated with HRQOL. However, older age was indirectly associated with better HRQOL via less severe PC perceptions. Further, this indirection association helped account for the positive association between age and HRQOL that three risk factors (income, comorbid disease burden, and sexual function) were shown to suppress. Perceptions of PC may promote HRQOL stability by mitigating age-related declines in health and income status. Disease perceptions thus represent critical components of health assessments and interventions for PC survivors of all ages, but particularly for men facing difficulties adapting to complex health profiles or normative lifespan challenges.

Most patients undergoing androgen deprivation therapy relapse eventually and progress to androgen-independent (AI) prostate cancer. Although the mechanisms underlying progression to AI prostate cancer are not well understood, studies suggest that androgen receptor (AR) is still required for AI prostate cancer. Our lab found that Vav3, a Rho GTPase guanine nucleotide exchange factor (GEF), is up-regulated during the progression of androgen-dependent human prostate cancer cells to androgen-independence in vivo and in cell-based experiments. Since Vav3 significantly increases ligand-dependent AR transcriptional activity and this action requires the Vav3 pleckstrin homology (PH) domain but not Vav3 GEF activity, we explored the role of the Vav3 PH domain in ligand-dependent AR coactivation by Vav3. We found that targeting the Vav3 PH mutant into nuclei but not the plasma membrane restored Vav3 PH mutant in AR coactivation. Targeting Vav3 to the plasma membrane eliminated the capacity of Vav3 to coactivate AR. In agreement with nuclear targeting of Vav3 via its PH domain, chromatin immunoprecipitation assays showed that Vav3 enhancement of AR transcriptional activity was accompanied by Vav3 recruitment to AR transcriptional complexes at an AR target gene enhancer. Further, Vav3 increased AR occupancy at the target gene enhancer upon androgen treatment and this may underlie the capacity of Vav3 to enhance AR transcriptional activity. Because Vav3 can also be activated by growth factors (GFs) and GFs activate AR in the absence of androgen (ligand-independent), we investigated the crosstalk between Vav3 and GF activation of AR and found Vav3 strongly enhanced AR transcriptional activity induced by GFs. GEF function and the downstream Rho GTPase, Rac1 were required for constitutively active (Ca) Vav3 activation of AR, which differs from Vav3 activation of AR in the presence of androgen. We also investigated the possible signal pathways contributing to AR activation by Ca Rac1. Ca Rac1 caused ligand-independent activation of AR in part through MAPK/ERK signaling and conferred prostate cancer growth in the absence of androgen in cell culture, soft agar and mouse tumor xenografts. Thus, our findings indicate that Vav3 activates AR in the presence or absence of ligand through two distinct mechanisms, which supports a versatile regulatory effect of Vav3 in AR signaling and prostate cancer progression.