Browsing by Subject "Prostate cancer"

Now showing 1 - 4 of 4
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    Clinical pharmacokinetics study of phenytoin in epilepsy patients & expression of oxysterol 7 Alpha - hydroxylase (hCYP7B1) in E.coli
    (2010-09) Aliwarga, Theresa
    The determination of pharmacokinetic parameters is crucial both for clinical studies and early in the drug discovery and development. This thesis describes a clinical pharmacokinetics study of one anticonvulsant drug, i.e. phenytoin (PHT) and the early screening study of potential chemopreventive agent for prostate cancer. PHT is extensively bound to plasma proteins, is excreted from the body as oxidative metabolites in the urine, and exhibits a non-linear pharmacokinetics profile. In this study, stable-labeled PHT was given either intravenously or intramuscularly. The simultaneous administration of oral and IV PHT enables a direct determination of the pharmacokinetic parameters of clearance, volume, half-life, and absolute oral bioavailability. Urine samples from epilepsy patients who were on maintenance therapy of PHT were collected from 0-12 hours and 12-24 hours after a single daily dose to measure the two principal PHT urinary metabolites, 5-(4-hydroxyphenyl)-5-phenylhydantoin (p-HPPH) and 5-(3,4-dihydroxy-1,5-cyclohexadien-1-yl)-5-phenylhydantoin (DHD). An isocratic HPLC-NI-APCI-MS method was used to quantify metabolites in urine. A weak, but significant, Spearman Rank Correlation was observed between the total urinary metabolites recovered and the oral bioavailability (p-value = 0.00924, r2= 0.166). The percent of dose recovered in urine ranged from 35.4% ± 15.7% in young adult patients (age 21-49 years old) and 32.9% ± 15.0% in patients of age 65-93 years indicating highly variable absorption. In contrast, absolute bioavailability was 0.864 ± 0.194 and 0.925 ± 0.252 for the two groups, as determined by the stable-isotope technique. Unaccounted biliary-fecal excretion of p-HPPH glucuronide, subjects’ noncompliance, and incomplete urine collection are possible explanations. Consequently, bioavailability is best determined by stable-isotope method. Chapter 2 of this thesis illustrates the early screening study of chemopreventive agent for prostate cancer. The rationale of this study was attempting to inhibit the metabolism of 5-androstane-3,17β-diol (3-Adiol). A metabolite of dihydrotestosterone, 3-Adiol, inhibits LNCaP prostate cell proliferation in the presence of Estrogen Receptor . CYP7B1 is the enzyme responsible for catalyzing the 6 and 7 hydroxylations of 3-Adiol in prostate. In this study, expression and purification of human CYP7B1 in E.coli was attempted. Despite spectroscopic evidence of P450 expression, the enzyme failed to turn over its endogenous substrate, DHEA to 7-hydroxy DHEA.
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    Development of multiparametric MRI models for prostate cancer detection based on improved correlative pathology
    (2014-06) Kalavagunta, Chaitanya
    Prostate cancer (PCa) is a prevalent disease which affects 1 in 6 men in the United States and has overtaken lung cancer as the leading cause of cancer related deaths in American men and number two worldwide. Among several diagnostic imaging tests that are available for detection of PCa in the market today, Magnetic Resonance Imaging (MRI) occupies a unique position in the detection of PCa due to its excellent soft tissue contrast and its ability to generate tissue property dependent multi-parametric data. While MRI has become an increasingly valuable tool in the management of men with PCa, its use to identify aggressive disease and characterize extent have yet to be developed. Multi-parametric MRI (MP-MRI) studies have been shown to increase sensitivity and specificity towards PCa detection compared to any single MRI dataset. The ability to develop and evaluate MP-MRI to prospectively detect disease, assess aggressiveness and delineate extent, first requires the retrospective validation against post-surgical pathology sections. Despite the large effort made by many groups in this area of research, the correlation of in vivo MP-MRI with pathology is still a challenge and to date is insufficient to develop highly accurate models of disease. To address this problem this thesis showcases (1) a novel registration approach called LATIS (Local Affine Transformation assisted by Internal Structures) for co-registering post prostatectomy pseudo-whole mount (PWM) pathological sections with in vivo MRI images and (2) MP-MRI based predictive model for disease detection using a composite biomarker score based on a unique database of pathology co-registered MR data sets. Also showcased in this thesis is a study where r1 and r2* relaxivities of a common paramagnetic contrast agent were measured in blood and saline at both 3T and 7T. This is important information to have when attempting to perform DCE-MRI studies as part of a MP-MRI protocol at ultra-high magnetic field strengths.
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    Organic Synthesis of a Small Novel Molecule to Target Prostate Cancer
    (2014) Just, Melissa J.; Mereddy, Venkatram
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    Role of transcriptional activation unit 5 (TAU5) in mediating transcriptional activity of androgen receptor splice variants
    (2012-12) Mutha, Sarita Kumari
    The standard treatment for advanced prostate cancer is chemical castration, which inhibits the activity of the androgen receptor (AR). Eventually, prostate cancer reemerges with a castration-resistant phenotype (CRPC) but still depends on AR signaling. One mechanism of AR activity in CRPC is the synthesis of AR splice variants, which lack the ligand binding domain. These splice variants function as constitutively active transcription factors that promote expression of endogenous AR target genes and support androgen independent prostate cancer cell growth. Previous work has shown transcriptional activation unit 5 (TAU5) is necessary for ligand independent activity of the full length AR in low or no androgen conditions and that this activation is mediated by the WHTLF motif. The purpose of this study was to determine whether the TAU5 region was also important for regulating the constitutive activity of truncated AR variants. We generated deletion mutants of the AR variants and tested transcriptional activity by luciferase assay. We found that that the constitutive, ligand independent transcriptional activity of truncated AR variants was dependent on TAU5 for transcription. Surprisingly, we found that AR variants did not require WHTLF to mediate this ligand independent activity. We attempted to narrow down the region that may be important for variant transcriptional activity and found that deletion of amino acids 420-490 resulted in lower activity compared to AR 1/2/3 CE3. However, testing smaller regions of 420-490 did not elucidate a specific motif. These findings highlight TAU5 as a key AR domain through which AR activity could be inhibited for treatment of CRPC.