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Full-Text Articles in Medicine and Health Sciences

Quantitative Analysis Of Tobacco Specific Nitrosamine In Human Urine Using Molecularly Imprinted Polymers As A Potential Tool For Cancer Risk Assessment, Kumar Shah Nov 2009

Quantitative Analysis Of Tobacco Specific Nitrosamine In Human Urine Using Molecularly Imprinted Polymers As A Potential Tool For Cancer Risk Assessment, Kumar Shah

Theses and Dissertations

Measuring urinary tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronide conjugate may provide the best biomarker of tobacco smoke lung carcinogen metabolism. Existence of differences in the extent of NNAL metabolism rates may be potentially related to an individuals’ lung cancer susceptibility. Low concentrations of NNAL in smokers urine (<1 ng/mL) require sensitive and selective methods for analysis. Traditionally, this involves extensive, time-consuming sample preparation that limits throughput and adds to measurement variability. Molecularly imprinted polymers (MIPs) have been developed for the analysis of urinary NNAL by offline cartridge extraction combined with LC-MS/MS. This method when reproduced demonstrated problems with matrix effects. In the first part of this work, investigation of matrix effects and related problems with sensitivity for the published offline extraction method has been conducted. In order to address the need to improve throughput and other analytical figures of merit for the original method, the second part of this work deals with development of a high-throughput online microfluidic method using capillary-columns packed with MIP beads for the analysis of urinary NNAL. The method was validated as per the FDA guidance, and enabled low volume, rapid analysis of urinary NNAL by direct injection on a microfluidic column packed with NNAL specific MIP beads. The method was used for analysis of urinary NNAL and NNAL-Gluc in smokers. Chemometric methods were used with this data to develop a potential cancer-risk-assessment tool based on pattern recognition in the concentrations of these compounds in urine. In the last part, method comparison approaches for the online and the offline sample extraction techniques were investigated. A ‘fixed’ range acceptance criterion based on combined considerations of method precision and accuracy, and the FDA bioanalytical guidance limits on precision and accuracy was proposed. Data simulations studies to evaluate the probabilities of successful transfers using the proposed criteria were performed. Various experimental designs were evaluated and a design comprised of 3 runs with 3 replicates each with an acceptance range of ±20% was found appropriate. The off-line and the on-line sample extraction methods for NNAL analysis were found comparable using the proposed fixed range acceptance criteria.


Impact Of Statin Therapy On Outcomes In Aneurysmal Subarachnoid Hemorrhage Patients, Abdulkhaliq Alsalman Oct 2009

Impact Of Statin Therapy On Outcomes In Aneurysmal Subarachnoid Hemorrhage Patients, Abdulkhaliq Alsalman

Theses and Dissertations

There is conflicting data on the effects of statins on cerebral vasospasm and clinical outcomes in aneurysmal subarachnoid hemorrhage (aSAH) patients. In this retrospective cohort study, patients were divided into those who received pravastatin (PRAV group) 40mg/d and those who did not (NP group). Data were analyzed using multivariate logistic regression. Eighty-one patients met inclusion criteria. There was a statistically significant decreased in the incidence of vasospasm in the PRAV group; however, this association did not retain significance after adjusting for WFNS, race, elevated WBC, and clipping (59% PRAV vs. 88% NP, p=0.08). There was no statistically significant difference in …


Effect Of Renin Angiotensin System Inhibition On Cardiovascular Sequelae In Elderly Hypertensive Patients With Insulin Resistance, Hala Zreikat Sep 2009

Effect Of Renin Angiotensin System Inhibition On Cardiovascular Sequelae In Elderly Hypertensive Patients With Insulin Resistance, Hala Zreikat

Theses and Dissertations

Background: Insulin resistance may play a pathogenic role in cardiovascular disease (CVD). Resistance to insulin has been associated with obesity, hypertension, and abnormal glucose and lipid metabolism. The constellation of these features among insulin resistant subjects has been called the metabolic syndrome. Prevalence of the metabolic syndrome increases with age and is most common in the elderly. Different criteria have been proposed to define the metabolic syndrome (ATP, WHO, AACE, EGIR). Current management of metabolic syndrome focuses on the specific risk factors that the patient may have without targeting the underlying insulin resistance. Angiotensin Converting Enzyme Inhibitors (ACEI) and Angiotensin …


Identification Of Clinical, Laboratory And Genetic Covariates For Pharmacokinetics, Efficacy And Toxicity Of Sorafenib In Patients With Solid Tumors, Lokesh Jain Aug 2009

Identification Of Clinical, Laboratory And Genetic Covariates For Pharmacokinetics, Efficacy And Toxicity Of Sorafenib In Patients With Solid Tumors, Lokesh Jain

Theses and Dissertations

The goal of this research work was to understand the clinical-pharmacology based treatment approaches for sorafenib. Treatment with sorafenib is associated with high inter-patient variability in pharmacokinetic exposures, efficacy and toxicity. We explored the demographic, laboratory, clinical and pharmacogenetic factors to elucidate the sources of variability. In addition, we examined the impact of pharmacogenetic variation in VEGFR2, an important mediator of the VEGF pathway, on risk of prostate cancer. To support these investigations, (mainly single-dose) pharmacokinetic, pharmacogenetic, efficacy and toxicity information were collected from patients with solid tumors, enrolled in five phase I / II clinical trials at National Cancer …


Age-Related Differences In In-Vitro Sensitivity To Inhibition Of Human Red Blood Cell Acetylcholinesterase And Plasma Butyrylcholinesterase By The Cholinesterase Inhibitors Physostigmine (Phys), Pyridostigmine (Pyr), Donepezil (Don) And Galantamine (Gal), David Lee Jul 2009

Age-Related Differences In In-Vitro Sensitivity To Inhibition Of Human Red Blood Cell Acetylcholinesterase And Plasma Butyrylcholinesterase By The Cholinesterase Inhibitors Physostigmine (Phys), Pyridostigmine (Pyr), Donepezil (Don) And Galantamine (Gal), David Lee

Theses and Dissertations

Alzheimer’s disease (AD) is a chronic, progressive neurodegenerative disorder, characterized clinically by a progressive loss of memory, cognitive function, ability to care for oneself and psychiatric symptoms. First-line agents for the treatment of AD are ChE inhibitors (DON, GAL), whose modest clinical efficacy and the high incidence of dose-limiting toxicities limit their clinical utility. In addition to AD, ChE inhibitors (PYR) are used for other medical conditions, such as myasthenia gravis (MG). Furthermore, ChE inhibitors (PYR) are used by military personnel prophylactically if impending exposure to chemical warfare agents, e.g., soman, is suspected. The purpose of this research project was …


To Evaluate The Level Of Agreement Between Two Self-Reported Medication Adherence Scales And Prescription Refill Records In Older Adults, Priyanka Kakad Jul 2009

To Evaluate The Level Of Agreement Between Two Self-Reported Medication Adherence Scales And Prescription Refill Records In Older Adults, Priyanka Kakad

Theses and Dissertations

Objective: To evaluate the level of agreement between two self-reported medication adherence scales and prescription refill records in older adults. Design: Cross-sectional study Setting: Imperial Plaza; a retirement community located in Richmond, Virginia. Participants: 32 independent-living older adults, taking anti-hypertensive medications and filling their prescriptions at on-site Plaza Professional Pharmacy were recruited in the study. Methods: Participants’ 6 months refill records were obtained and Medication Possession Ration (MPR) was calculated. Participants were interviewed using Morisky Medication Adherence Scale (MMAS) & Brief Medication Questionnaire (BMQ). Kappa statistics was used to evaluate the level of agreement. Results: Poor level of agreement was …


Factors Influencing Placental Transfer Of Lopinavir: Binding, Uptake And Efflux, Abhishek Gulati Jun 2009

Factors Influencing Placental Transfer Of Lopinavir: Binding, Uptake And Efflux, Abhishek Gulati

Theses and Dissertations

HIV protease inhibitors are an important component of Highly Active Antiretroviral Therapy used to treat HIV infected pregnant women. They have a low placental transfer and are highly plasma protein bound. The purpose of this thesis was to characterize the factors limiting placental passage and fetal exposure to lopinavir. These factors include lopinavir plasma protein binding and uptake, cellular binding, and efflux of lopinavir in the placental trophoblast cells. First, we determined the unbound fraction of lopinavir in cord blood and characterized the binding of lopinavir to α1-acid glycoprotein (AAG) and human serum albumin (HSA), and displacement by ritonavir. Serum …


The Use Of Lactobacillus In The Treatment Of Clostridium Difficile Infection In Hospitalized Adult Patients, Ali Alhammad Apr 2009

The Use Of Lactobacillus In The Treatment Of Clostridium Difficile Infection In Hospitalized Adult Patients, Ali Alhammad

Theses and Dissertations

Objective To describe the use of Lactobacillus by hospitalized patients and to examine its relationship with various Clostridium difficile infection (CDI) related outcomes. Methods The characteristics of Lactobacillus users and non-users and the initiation of Lactobacillus with respect to initiation of antibiotic therapy and CDI treatment were described using national hospital discharge database. The relationships between Lactobacillus use and post-CDI length of stay, mortality, switch of CDI therapy, and readmission were analyzed. Results Lactobacillus users and non-users were different in most characteristics. Metronidazole and fluoroquinolones were the most frequently used antibiotics by Lactobacillus users. They were mainly CDI cases, used …


The Economic Impact Of Antimicrobial Resistance In Patients With Nosocomial Staphylococcus Aureus Bacteremia, Suzanne Phillips Apr 2009

The Economic Impact Of Antimicrobial Resistance In Patients With Nosocomial Staphylococcus Aureus Bacteremia, Suzanne Phillips

Theses and Dissertations

Background: The proportion of nosocomial Staphylococcus infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has increased from 22% in 1995 to 63% in 2004. Blood stream infections, more commonly referred to as bacteremias, represented the majority (75.5%) of hospital-onset MRSA cases. The economic impact of Staphylococcus aureus bacteremia merits investigation. Methods: This was a retrospective cohort analysis within Cerner HealthFacts data warehouse. Eligible patients were those who had Staphylococcus aureus bacteremia and were discharged between January 1, 2000, and December 31, 2006. Inclusion criteria include age > 18 years old and onset of infection > 48 hours post admission. The crude association was …


Pulmonary Delivery Of Anorectic Gut Secreted Peptides For Appetite Suppression In Rats, Priya Nadkarni Jan 2009

Pulmonary Delivery Of Anorectic Gut Secreted Peptides For Appetite Suppression In Rats, Priya Nadkarni

Theses and Dissertations

This dissertation project aimed to demonstrate that pulmonary delivery of two anorectic gut secreted peptides, peptide YY (PYY) and oxyntomodulin (OXM) enabled food intake suppression and reduced body weight gain in rats via their systemic absorption from the lung and interaction with the brain. After PYY and OXM were administered to the lungs at varying doses, food intake and body weight gain were monitored in freely feeding rats. Significant 30-35 % food intake suppression was achieved for 4-6 h following pulmonary administration of endogenously active PYY3-36 and OXM1-37 at 0.80 and 0.50 mg/kg, respectively. Moreover, when administered daily for 7 …