Digital Commons Network^™

Dynamic Chemical Shift Imaging For Image-Guided Thermal Therapy, Brian A. Taylor

Dissertations and Theses (Open Access)

Magnetic resonance temperature imaging (MRTI) is recognized as a noninvasive means to provide temperature imaging for guidance in thermal therapies. The most common method of estimating temperature changes in the body using MR is by measuring the water proton resonant frequency (PRF) shift. Calculation of the complex phase difference (CPD) is the method of choice for measuring the PRF indirectly since it facilitates temperature mapping with high spatiotemporal resolution. Chemical shift imaging (CSI) techniques can provide the PRF directly with high sensitivity to temperature changes while minimizing artifacts commonly seen in CPD techniques. However, CSI techniques are currently limited by …

An Innovative Phase I Trial Design Allowing For The Identification Of Multiple Potential Maximum To Lerated Doses With Combination Therapy Of Targeted Agents, Sarina A. Piha-Paul

Dissertations and Theses (Open Access)

Treatment for cancer often involves combination therapies used both in medical practice and clinical trials. Korn and Simon listed three reasons for the utility of combinations: 1) biochemical synergism, 2) differential susceptibility of tumor cells to different agents, and 3) higher achievable dose intensity by exploiting non-overlapping toxicities to the host. Even if the toxicity profile of each agent of a given combination is known, the toxicity profile of the agents used in combination must be established. Thus, caution is required when designing and evaluating trials with combination therapies. Traditional clinical design is based on the consideration of a single …

Nherf1 – New Modifier Of Colorectal Cancer Progression, Yuho Hayashi

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) develops from multiple progressive modifications of normal intestinal epithelium into adenocarcinoma. Loss of cell polarity has been implicated as an early event in this process, but the molecular players involved are not well known. NHERF1 (Na+/H+ Exchanger Regulatory Factor 1) is an adaptor protein with apical membrane localization in polarized epithelia. In this study, we tested our hypothesis that NHERF1 plays a role in CRC. We examined surgical CRC resection specimens for changes in NHERF1 expression, and modeled these changes in two- and three-dimensional (2D and 3D) Caco-2 CRC cell systems. NHERF1 had significant alterations from normal …

Targeting The Blood-Brain Barrier With A Non-Canonical Iron-Mimicry Mechanism, Michael G. Ozawa

Dissertations and Theses (Open Access)

Treatment of central nervous system (CNS) diseases is limited by the blood-brain barrier (BBB), a selective vascular interface restricting passage of most molecules from blood into brain. Specific transport systems have evolved allowing circulating polar molecules to cross the BBB and gain access to the brain parenchyma. However, to date, few ligands exploiting such systems have proven clinically viable in the setting of CNS diseases.

We reasoned that combinatorial phage-display screenings in vivo would yield peptides capable of crossing the BBB and allow for the development of ligand-directed targeting strategies of the brain. Here we show the identification of a …

Characterizing A Novel Genetic Locus Associated With Familial Co-Occurrence Of Thoracic Aortic Aneurysms And Intracranial Aneurysms, Alexander H. Li

Dissertations and Theses (Open Access)

The Mendelian inheritance of genetic mutations can lead to adult-onset cardiovascular disease. Several genetic loci have been mapped for the familial form of Thoracic Aortic Aneurysms (TAA), and many causal mutations have been identified for this disease. Intracranial Aneurysms (ICA) also show linkage heterogeneity, but no mutations have been identified causing familial ICA alone.

Here, we characterized a large family (TAA288) with an autosomal dominant pattern of inherited aneurysms. It is intriguing that female patients predominantly present with ICA and male patients predominantly with TAA in this family. To identify a causal mutation in this family, a genome-wide linkage analysis …

Passive Transfer Of Igg Anti-Gm1 Antibodies Impairs Peripheral Nerve Repair, Pablo H Lopez, Gang Zhang, Jiangyang Zhang, Helmar C Lehmann, John W Griffin, Ronald L Schnaar, Kazim A Sheikh

Faculty, Staff and Student Publications

Anti-GM1 antibodies are present in some patients with autoimmune neurological disorders. These antibodies are most frequently associated with acute immune neuropathy called Guillain-Barré syndrome (GBS). Some clinical studies associate the presence of these antibodies with poor recovery in GBS. The patients with incomplete recovery have failure of nerve repair, particularly axon regeneration. Our previous work indicates that monoclonal antibodies can inhibit axon regeneration by engaging cell surface gangliosides (Lehmann et al., 2007). We asked whether passive transfer of human anti-GM1 antibodies from patients with GBS modulate axon regeneration in an animal model. Human anti-GM1 antibodies were compared with other GM1 …

Insider Express Blog;New Library Catalog Interface;Stat!Ref, Vol.8 (7), Houston Academy Of Medicine-Texas Medical Center Library

Insider Express (2003-2013)

No abstract provided.

Gsbs News, Summer 2010, Graduate School Of Biomedical Sciences, University Of Texas Health Science Center At Houston/M.D. Anderson Cancer Center

GSBS News

No abstract provided.

Influence Of Blood Contamination On Bond Strength Of A Self-Etching System, Ellen Cristina De Carvalho Mendonça, Samuel Nilo Vieira, Fernando Aparecido Kawaguchi, John Powers, Adriana Bona Matos

Faculty, Staff and Student Publications

OBJECTIVES: To detect the influence of blood contamination (BC) on the bond strength (BS) of a self-etching bonding system (SES) to enamel and dentine.

METHODS: 25 human molars were longitudinally sectioned on the mesio-distal axis in order to obtain 50 specimens, which were embedded in acrylic resin. At first, the specimens were ground to expose a flat surface of enamel, and a bond strength test was performed. Afterwards, the samples were ground again in order to obtain a flat surface of dentine. Ten groups (total: n=100) were assigned according to substrate (enamel and dentine), step in the bonding sequence when …

Progressive Regression Of Left Ventricular Hypertrophy Two Years After Bariatric Surgery, Mohamed F Algahim, Thomas R Lux, Joshua G Leichman, Anthony F Boyer, Charles C Miller, Susan T Laing, Erik B Wilson, Terry Scarborough, Sherman Yu, Brad Snyder, Carol Wolin-Riklin, Ursula G Kyle, Heinrich Taegtmeyer

Faculty, Staff and Student Publications

BACKGROUND: Obesity is a systemic disorder associated with an increase in left ventricular mass and premature death and disability from cardiovascular disease. Although bariatric surgery reverses many of the hormonal and hemodynamic derangements, the long-term collective effects on body composition and left ventricular mass have not been considered before. We hypothesized that the decrease in fat mass and lean mass after weight loss surgery is associated with a decrease in left ventricular mass.

METHODS: Fifteen severely obese women (mean body mass index [BMI]: 46.7+/-1.7 kg/m(2)) with medically controlled hypertension underwent bariatric surgery. Left ventricular mass and plasma markers of systemic …

Data Accuracy In Medical Record Abstraction, Meredith Nahm

Dissertations and Theses (Open Access)

Clinical Research Data Quality Literature Review and Pooled Analysis

We present a literature review and secondary analysis of data accuracy in clinical research and related secondary data uses. A total of 93 papers meeting our inclusion criteria were categorized according to the data processing methods. Quantitative data accuracy information was abstracted from the articles and pooled. Our analysis demonstrates that the accuracy associated with data processing methods varies widely, with error rates ranging from 2 errors per 10,000 files to 5019 errors per 10,000 fields. Medical record abstraction was associated with the highest error rates (70–5019 errors per 10,000 fields). …

Polymorphisms Of The Dna Repair Gene Mgmt And Risk And Progression Of Head And Neck Cancer, Zhengdong Zhang, Luo Wang, Sheng Wei, Zhensheng Liu, Li-E Wang, Erich M Sturgis, Qingyi Wei

Faculty, Staff and Student Publications

Methylating agents are involved in carcinogenesis, and the DNA repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) removes methyl group from O(6)-methylguanine. Genetic variation in DNA repair genes has been shown to contribute to susceptibility to squamous cell carcinoma of the head and neck (SCCHN). We hypothesize that MGMT polymorphisms are associated with risk of SCCHN. In a hospital-based case-control study of 721 patients with SCCHN and 1234 cancer-free controls frequency-matched by age, sex and ethnicity, we genotyped four MGMT polymorphisms, two in exon 3, 16195C>T and 16286C>T and two in the promoter region, 45996G>T and 46346C>A. We found …

Library Closed On Monday, May 31; Refworks Mobile Access, Vol.8 (5), Houston Academy Of Medicine-Texas Medical Center Library

Insider Express (2003-2013)

No abstract provided.

Perfusion In Rat Brain At 7 T With Arterial Spin Labeling Using Fair-Truefisp And Quipss, Emilio Esparza-Coss, Jarek Wosik, Ponnada A Narayana

Faculty, Staff and Student Publications

Measurement of perfusion in longitudinal studies allows for the assessment of tissue integrity and the detection of subtle pathologies. In this work, the feasibility of measuring brain perfusion in rats with high spatial resolution using arterial spin labeling is reported. A flow-sensitive alternating recovery sequence, coupled with a balanced gradient fast imaging with steady-state precession readout section was used to minimize ghosting and geometric distortions, while achieving high signal-to-noise ratio. The quantitative imaging of perfusion using a single subtraction method was implemented to address the effects of variable transit delays between the labeling of spins and their arrival at the …

Delta Like Ligand 4 Is A Critical Regulator Of Bone Marrow Cell Differentiation Into Pericytes/Vascular Smooth Muscle Cells And Is Essential For The Vasculogenesis That Supports The Growth Of Ewing’S Sarcoma, Keri L. Stewart

Dissertations and Theses (Open Access)

We have previously shown that vasculogenesis, the process by which bone marrow-derived cells are recruited to the tumor and organized to form a blood vessel network de novo, is essential for the growth of Ewing’s sarcoma. We further demonstrated that these bone marrow cells differentiate into pericytes/vascular smooth muscle cells(vSMC) and contribute to the formation of the functional vascular network. The molecular mechanisms that control bone marrow cell differentiation into pericytes/vSMC in Ewing’s sarcoma are poorly understood. Here, we demonstrate that the Notch ligand Delta like ligand 4 (DLL4) plays a critical role in this process. DLL4 is essential for …

Efficacy And Mechanism Of Â-Defensin2 Fused Antigen Protein Vaccines, Hyun J. Park

Dissertations and Theses (Open Access)

Vaccines which use the strategy of fusing adjuvant murine â-defensin2 (mBD2) to an antigen in order to elicit stronger anti-antigen immune responses are referred to as murine â-defensin2 (mBD2) vaccines. Previous studies have validated the potential of mBD2 vaccines, thus in this study we focus on increasing vaccine efficacy as well as mechanism elucidation. Initially, we demonstrate superior IFN-ã release levels by antigen specific effector T cells when antigen is crosspresented by dendritic cells (DC) which absorbed mBD2 vaccine (mBD2 fused antigen protein) over antigen alone. We move unto an in vivo model and note significant increases in the expansion …

Il-2 Regulation Of Il-24 Expression Leads To Growth Suppression Of Melanoma Cells, Emily Jen

Dissertations and Theses (Open Access)

Melanoma is known to be highly resistant to chemotherapy. Treatment with high dose IL-2 has shown significant clinical benefit in a minority of metastatic melanoma patients and has lead to long term survival in a few cases. However, this treatment is associated with excessive multiorgan toxicities, which severely limits its use. We hypothesize that one mechanism of effective IL-2 therapy is through the direct upregulation of IL-24 production in melanoma tumors and subsequent IL-24 mediated tumor growth suppression.

Five melanoma cell lines were treated with high dose recombinant hIL-2 at 1000U/ml. Three of the cell lines (A375, WM1341, WM793) showed …

Damage-Induced Inflammation And Nociceptive Hypersensitivity In Drosophila Larvae, Daniel T. Babcock

Dissertations and Theses (Open Access)

Mounting an effective response to tissue damage requires a concerted effort from a number of systems, including both the immune and nervous systems. Immune-responsive blood cells fight infection and clear debris from damaged tissues, and specialized pain receptors become hypersensitive to promote behavior that protects the damaged area while it heals. To uncover the cellular and molecular mechanisms underlying these processes, we have developed a genetically tractable invertebrate model of damage-induced inflammation and pain hypersensitivity using Drosophila larvae.

To study wound-induced inflammation, we generated transgenic larvae with fluorescent epidermal cells and blood cells (hemocytes). Using live imaging, we monitored the …

Myogenin Modulates Exercise Endurance By Altering Skeletal Muscle Metabolism, James Eric Meadows

Dissertations and Theses (Open Access)

The function of myogenic regulatory factors (MRFs) during adult life is not well understood. The requirement of one of these MRFs, myogenin (Myog), during embryonic muscle development suggests an equally important role in adult muscle. In this study, we have determined the function of myogenin during adult life using a conditional allele of Myog. In contrast to embryonic development, myogenin is not required for adult viability, and Myog-deleted mice exhibited no remarkable phenotypic changes during sedentary life. Remarkably, sedentary Myog-deleted mice demonstrated enhanced exercise endurance during involuntary treadmill running. Altered blood glucose and lactate levels in sedentary Myog-deleted mice after …

Signaling Mechanisms That Control Gap Junctional Coupling Between Retinal Neurons, Wade Kothmann

Dissertations and Theses (Open Access)

Gap junctions between neurons form the structural substrate for electrical synapses. Connexin 36 (Cx36, and its non-mammalian ortholog connexin 35) is the major neuronal gap junction protein in the central nervous system (CNS), and contributes to several important neuronal functions including neuronal synchronization, signal averaging, network oscillations, and motor learning. Connexin 36 is strongly expressed in the retina, where it is an obligatory component of the high-sensitivity rod photoreceptor pathway. A fundamental requirement of the retina is to adapt to broadly varying inputs in order to maintain a dynamic range of signaling output. Modulation of the strength of electrical coupling …

Smooth Muscle Hyperplasia Due To Acta2/Myh11 Mutations: Identification Of Novel Pathology And Pathways Leading To Aneurysms And Diverse Vascular Occlusive Diseases, Christina L. Papke

Dissertations and Theses (Open Access)

Missense mutations in smooth muscle cell (SMC) specific ACTA2 (á-actin) and MYH11 (â-myosin heavy chain) cause diffuse and diverse vascular diseases, including thoracic aortic aneurysms and dissections (TAAD) and early onset coronary artery disease and stroke. The mechanism by which these mutations lead to dilatation of some arteries but occlusion of others is unknown. We hypothesized that the mutations act through two distinct mechanisms to cause varied vascular diseases: a loss of function, leading to decreased SMC contraction and aneurysms, and a gain of function, leading to increased SMC proliferation and occlusive disease. To test this hypothesis, ACTA2 mutant SMCs …

The Consequences Of Disrupting The Mdm2-P53 Balance In Hematopoiesis, Hussein A. Abbas

Dissertations and Theses (Open Access)

The bone marrow accommodates hematopoietic stem cells and progenitors. These cells provide an indispensible resource for replenishing the blood constituents throughout an organism’s life. A tissue with such a high turn-over rate mandates intact cycling checkpoint and apoptotic pathways to avoid inappropriate cell proliferation and ultimately the development of leukemias. p53, a major tumor suppressor, is a transcription factor that regulates cell cycle, and induces apoptosis and senescence. Mice inheriting a hypomorphic p53 allele in the absence of Mdm2, a p53 inhibitor, have elevated p53 cell cycle activity and die by postnatal day 13 due to hematopoietic failure. Hematopoiesis progresses …

Host-Pathogen Interactions Of Secreted And Surface Staphylococcus Aureus Factors, Vanessa Vazquez

Dissertations and Theses (Open Access)

Staphylococcus aureus is an opportunistic bacterial pathogen that can infect humans and other species. It utilizes an arsenal of virulence factors to cause disease, including secreted and cell wall anchored factors. Secreted toxins attack host cells, and pore-forming toxins destroy target cells by causing cell lysis. S. aureus uses cell-surface adhesins to attach to host molecules thereby facilitating host colonization. The Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are a family of cell-wall anchored proteins that target molecules like fibronectin and fibrinogen. The Serine-aspartate repeat (Sdr) proteins are a subset of staphylococcal MSCRAMMs that share similar domain organization. Interestingly, …

The Role Of Mucosal Epithelial Cells In Hiv-1 Infection, Danielle Fontenot

Dissertations and Theses (Open Access)

The predominant route of human immunodeficiency virus type 1 (HIV-1) transmission is infection across the vaginal mucosa. Epithelial cells, which form the primary barrier of protection against pathogens, are the first cell type at these mucosal tissues to encounter the virus but their role in HIV infection has not been clearly elucidated. Although mucosal epithelial cells express only low levels of the receptors required for successful HIV infection, productive infection does occur at these sites. The present work provides evidence to show that HIV exposure, without the need for productive infection, induces human cervical epithelial cells to produce Thymic Stromal …

Thoracic Radiotherapy Treatment Planning With Cine Pet/Ct, Adam C. Riegel

Dissertations and Theses (Open Access)

Purpose: Respiratory motion causes substantial uncertainty in radiotherapy treatment planning. Four-dimensional computed tomography (4D-CT) is a useful tool to image tumor motion during normal respiration. Treatment margins can be reduced by targeting the motion path of the tumor. The expense and complexity of 4D-CT, however, may be cost-prohibitive at some facilities. We developed an image processing technique to produce images from cine CT that contain significant motion information without 4D-CT. The purpose of this work was to compare cine CT and 4D-CT for the purposes of target delineation and dose calculation, and to explore the role of PET in target …

Ampa Receptor Allosterism: Measurement Of The Conformational Changes In The Ligand Binding Domain Of A Functional Receptor, Jennifer Gonzalez-Mcgehee

Dissertations and Theses (Open Access)

Ionotropic glutamate receptors are important excitatory neurotransmitter receptors in the mammalian central nervous system that have been implicated in a number of neuropathologies such as epilepsy, ischemia, and amyotrophic lateral sclerosis. Glutamate binding to an extracellular ligand binding domain initiates a series of structural changes that leads to the formation of a cation selective transmembrane channel, which consequently closes due to desensitization of the receptor. The crystal structures of the AMPA subtype of the glutamate receptor have been particularly useful in providing initial insight into the conformational changes in the ligand binding domain; however, these structures are limited by crystallographic …

Type I Insulin-Like Growth Factor Receptor Tyrosine Kinase As A Molecular Target In Mantle Cell Lymphoma, Deeksha Vishwamitra

Dissertations and Theses (Open Access)

Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoid malignancy representing 5-10% of all non-Hodgkin’s lymphomas. It is distinguished by the t(11;14)(q13;q32) chromosomal translocation that juxtaposes the proto-oncogene CCND1, which encodes cyclin D1 at 11q13 to the IgH gene at 14q32. MCL patients represent about 6% of all new cases of Non-Hodgkin’s lymphomas per year or about 3,500 new cases per year. MCL occurs more frequently in older adults – the average age at diagnosis is the mid-60s with a male-to-female ratio of 2-3:1. It is typically characterized by the proliferation of neoplastic B-lymphocytes in the mantle zone of the …

Characterization And Optimization Of Antigen-Specific T Cell Responses During Ex Vivo Expansion Of Melanoma Tumor-Infiltrating Lymphocytes, Yufeng Li

Dissertations and Theses (Open Access)

Treatment of metastatic melanoma with tumor reactive T cells (adoptive T cell therapy, ACT) is a promising approach associated with a high clinical response rate. However, further optimization of this treatment modality is required to increase the clinical response after this therapy. ACT in melanoma involves an initial phase (pre-REP) of tumor-infiltrating lymphocyte (TIL) expansion ex vivo from tumor isolates followed by a second phase, “rapid expansion protocol” (REP) generating the billions of cells used as the TIL infusion product. The main question addressed in this thesis was how the currently used REP affected the responsiveness of the CD8+ T …

Protein-Protein Interactions That Regulate Neurotransmitter Release From Retinal Ribbon Synapses, (Leigh) Beth T. Latham

Dissertations and Theses (Open Access)

Protein-Protein Interactions That Regulate Neurotransmitter Release from Retinal Ribbon Synapses Photoreceptors and bipolar cells in the retina form specialized chemical synapses called ribbon synapses. This type of synapse differs physiologically from “conventional” chemical synapses. While “conventional” synapses exocytose neurotransmitter-filled vesicles in an all-or-none fashion in response to an action potential, a retinal ribbon synapse can release neurotransmitter tonically (sustained) in response to graded changes in membrane potential or phasically (transient) in response to a large change in membrane potential.

Synaptic vesicle exocytosis is a tightly controlled process involving many protein-protein interactions. Therefore, it is likely that the dissimilarity in the …

The Expression And Cellular Localization Of Cc-Chemokine Receptor 5 (Ccr5) After Traumatic Brain Injury, Vuvi H. Nguyen

Dissertations and Theses (Open Access)

Traumatic brain injury results from a primary insult and secondary events that together result in tissue injury. This primary injury occurs at the moment of impact and damage can include scalp laceration, skull fraction, cerebral contusions and lacerations as well as intracranial hemorrhage. Following the initial insult, a delayed response occurs and is characterized by hypoxia, ischemia, cerebral edema, and infection. During secondary brain injury, a series of neuroinflammatory events are triggered that can produce additional damage but may also help to protect nervous tissue from invading pathogens and help to repair the damaged tissue. Brain microglia and astrocytes become …