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The Combined Effect Of In-Situ Tumor And Irradiation On Peritumoral Brain Vasculature, Janice Ann Zawaski

Theses and Dissertations (ETD)

In the USA, 200,000 brain tumors are diagnosed each year with glioma representing 8.4% of the 200,000. The standard treatment for glioma consists of surgical resection, when possible, followed by radiation therapy (RT) and/or chemotherapy. Radiation therapy is one of the most effective treatments of brain tumors; however, the therapeutic ratio of RT is limited by damage to the normal tissue. We hypothesize that tumor growth has an adverse effect on the peritumoral tissue through the angiogenic/inflammatory environment it creates rendering it susceptible to further damage by RT which may be prevented by using anti-angiogenic/anti-inflammatory agents. We have developed a …

Basement Membrane Proteoglycans: Modulators Par Excellence Of Cancer Growth And Angiogenesis., Renato V. Iozzo, Jason J. Zoeller, Alexander Nyström

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Proteoglycans located in basement membranes, the nanostructures underling epithelial and endothelial layers, are unique in several respects. They are usually large, elongated molecules with a collage of domains that share structural and functional homology with numerous extracellular matrix proteins, growth factors and surface receptors. They mainly carry heparan sulfate side chains and these contribute not only to storing and preserving the biological activity of various heparan sulfate-binding cytokines and growth factors, but also in presenting them in a more "active configuration" to their cognate receptors. Abnormal expression or deregulated function of these proteoglycans affect cancer and angiogenesis, and are critical …

Generation And Characterization Of A Knock-In Allele Of Eklf: Probing The In Vivo Role Of The Chromatin Remodeling Domain In Definitive Hematopoietic Cells, Valerie Malyvanh Jansen

Theses and Dissertations (ETD)

The zinc finger-encoding transacting factor EKLF, or erythroid Krüppel-like factor, binds key regulatory elements of many erythroid-specific genes, and is essential for definitive erythropoiesis. Mice lacking this factor die of anemia by E15.5 of gestation, failing to activate β-globin gene transcription, and demonstrating a block in the erythroid differentiation program at the primitive erythroblast stage. In contrast, megakaryocytic progenitors are amplified in EKLF-null embryos, with increased Fli-1 gene expression, a marker of early megakaryocytic differentiation. These observations are consistent with the idea that EKLF modulates the megakaryocytic-erythroid (M-E) differentiation switch.

Our laboratory has previously demonstrated that an amino terminal sequence …

Pax5 Haploinsufficiency Cooperates With Bcr-Abl1 To Induce Acute Lymphoblastic Leukemia, Christopher B. Miller

Theses and Dissertations (ETD)

Acute lymphoblastic leukemia (ALL) is the commonest pediatric malignancy and comprises several distinct subtypes each with its own unique pathogenesis, clinical behavior, and response to therapy. Chromosomal aberrations are a hallmark of ALL but alone fail to induce leukemia. Pediatric ALLs can be divided into several categories based on the expression of several genetically conserved chromosomal translocations including the t(9,22)[BCR-ABL1], t(1,19)[TCF3-PBX1], t(12,21)[ETV6-RUNX1], MLLrearranged leukemia’s, hyperdiploid and hypodiploid karyotypes, and T-lineage leukemia. Each translocation confers a characteristic transforming phenotype within the cell in which it originates but is alone insufficient to induce overt leukemia. …

Insights Into Btb-Cul3 Ubiquitin Ligases From The Structures Of Spop-Substrate Complexes, Min Zhuang

Theses and Dissertations (ETD)

Cullin-Ring ubiquitin ligases (CRLs) are E3 complexes that specifically recognize substrates through substrate adaptors. In the largest CRL subfamily, Cul3 binds a BTB domain, and a protein-interaction domain such as MATH recruits substrates for ubiquitination. Here we present biochemical and structural analyses of the MATH and BTB domain containing protein, SPOP, which regulates diverse signaling pathways. First, we identified a conserved SPOP Binding Consensus (SBC) motif in the transcriptional regulator Ci, the protein phosphatase Puc, and the chromatin component MacroH2A. The SBC motif specifically binds the MATH domain of SPOP, and is required for Puc ubiquitination in vitro and in …

Structural And Kinetics Studies Of The Enzyme Dihydropteroate Synthase And The Implications For Antibiotic Resistance, Katherine A. Ayers

Theses and Dissertations (ETD)

The goal of this study is to develop small molecule inhibitors of DHPS for the treatment of a variety of infectious diseases. According to the World Health Organization (WHO), infectious diseases kill more than 13 million people worldwide every year making it the second leading cause of death behind cardiovascular disease. The sulfonamide class of drugs has been in use since the 1930’s to treat many infectious agents and act by targeting the enzyme dihydropteroate synthase (DHPS) of the prokaryotic and lower eukaryotic folate pathway.

DHPS is an ideal drug target because humans do not synthesize folate de novo and …

Obesity, Adiposity, And Satiety In Mouse Models Of Smith-Magenis Syndrome And Dup(17)(P11.2) Syndrome, Brooke Burns

Theses and Dissertations

Smith-Magenis syndrome (SMS) is a complex disorder caused by haploinsufficiency of RAI1 and characterized by sleep disturbances, behavioral abnormalities, mental retardation, and obesity in teens and adults. Rai1+/- mice are obese after 20 weeks. Dup(17)(p11.2) syndrome is a complex disorder associated with overexpression of RAI1. A transgenic mouse model of dup(17)(p11.2) syndrome overexpresses Rai1 and results in a mouse that is growth delayed. In order to characterize the obese phenotypes of mouse models of SMS and the role of RAI1 in obesity, daily food intake and serum levels of insulin, glucose, PPY, and leptin were measured; adiposity was studied by …

Upregulation Of Pip3-Dependent Rac Exchanger 1 (P-Rex1) Promotes Prostate Cancer Metastasis., Jianbing Qin, Yan Xie, Bo Wang, Mikio Hoshino, Dennis W. Wolff, Jing Zhao, Margaret A. Scofield, Frank J. Dowd, Ming-Fong Lin, Yaping Tu

Journal Articles: Biochemistry & Molecular Biology

Excessive activation of G-protein-coupled receptor (GPCR) and receptor tyrosine kinase (RTK) pathways has been linked to prostate cancer metastasis. Rac activation by guanine nucleotide exchange factors (GEFs) plays an important role in directional cell migration, a critical step of tumor metastasis cascades. We found that the upregulation of P-Rex1, a Rac-selective GEF synergistically activated by Gbetagamma freed during GPCR signaling, and PIP3, generated during either RTK or GPCR signaling, strongly correlates with metastatic phenotypes in both prostate cancer cell lines and human prostate cancer specimens. Silencing endogenous P-Rex1 in metastatic prostate cancer PC-3 cells selectively inhibited Rac activity and reduced …

Metallic Nickel Nano- And Fine Particles Induce Jb6 Cell Apoptosis Through A Caspase-8/Aif Mediated Cytochrome C-Independent Pathway, Jinshun Zhao, Linda Bowman, Xingdong Zhang, Xianglin Shi, Binghua Jiang, Vincent Castranova, Min Ding

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: Carcinogenicity of nickel compounds has been well documented. However, the carcinogenic effect of metallic nickel is still unclear. The present study investigates metallic nickel nano- and fine particle-induced apoptosis and the signal pathways involved in this process in JB6 cells. The data obtained from this study will be of benefit for elucidating the pathological and carcinogenic potential of metallic nickel particles.

RESULTS: Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we found that metallic nickel nanoparticles exhibited higher cytotoxicity than fine particles. Both metallic nickel nano- and fine particles induced JB6 cell apoptosis. Metallic nickel nanoparticles produced higher apoptotic induction than fine …

The Proteolytic Stability And Cytotoxicity Studies Of L‐Aspartic Acid And L‐Diaminopropionic Acid Derived Β‐Peptides And A Mixed Α/Β‐Peptide, Sahar Ahmed, Kamaljit Kaur

Pharmacy Faculty Articles and Research

The use of peptides as drugs in pharmaceutical applications is hindered by their susceptibility to proteolysis and therefore low bioavailability. β‐Peptides that contain an additional methylene group in the backbone, are gaining recognition from a pharmaceutical stand point as they are considerably more resilient to proteolysis and metabolism. Recently, we reported two new classes of β‐peptides, β³‐ and β²‐peptides derived from l‐aspartic acid and l‐diaminopropionic acid, respectively. Here, we report the proteolytic stability of these β‐peptidic compounds and a mixed α /β‐peptide against three enzymes (pronase, trypsin and elastase), as well as, human serum. The …

Defining Family: Naming, Orientation, And Redemption In The Case Of Terri Schiavo, M. Chad Mcbride, Karen L. Taas, Paige W. Toller

Communication Faculty Publications

This paper undertakes a detailed analysis of the Terri Schiavo case as it was covered in popular media. Drawing on Burkean theory, we argue a critical issue in the case was a struggle between Terri's parents and husband to be seen as the more legitimate family in order to determine the duration and extent of Terri 's medical care. We discuss how the private debate over Terri's health and the decision to remove her feeding tube entered into the public scenes of legal and political action. This shift to the public scene represented problems for the parties directly involved in …

Regulation Of The Mazef Toxin-Antitoxin Module In Staphylococcus Aureus And Its Impact On Sigb Expression, Niles P. Donegan, Ambrose L. Cheung

Dartmouth Scholarship

In Staphylococcus aureus, the sigB operon codes for the alternative sigma factor σ^Band its regulators that enable the bacteria to rapidly respond to environmental stresses via redirection of transcriptional priorities. However, a full model of σ^Bregulation in S. aureus has not yet emerged. Earlier data has suggested that mazEF, a toxin-antitoxin (TA) module immediately upstream of the sigB operon, was transcribed with the sigB operon. Here we demonstrate that the promoter P_mazE upstream of mazEF is essential for full σ^B activity and that instead of utilizing autorepression typical of TA systems, sigB …

Long-Distance Delivery Of Bacterial Virulence Factors By Pseudomonas Aeruginosa Outer Membrane Vesicles, Jennifer M. Bomberger, Daniel P. Maceachran, Bonita A. Coutermarsh, Siying Ye, George A. O'Toole, Bruce A. Stanton, Frederick M. Ausubel

Dartmouth Scholarship

Bacteria use a variety of secreted virulence factors to manipulate host cells, thereby causing significant morbidity and mortality. We report a mechanism for the long-distance delivery of multiple bacterial virulence factors, simultaneously and directly into the host cell cytoplasm, thus obviating the need for direct interaction of the pathogen with the host cell to cause cytotoxicity. We show that outer membrane–derived vesicles (OMV) secreted by the opportunistic human pathogen Pseudomonas aeruginosa deliver multiple virulence factors, including β-lactamase, alkaline phosphatase, hemolytic phospholipase C, and Cif, directly into the host cytoplasm via fusion of OMV with lipid rafts in the host plasma …

Y27632, A Rho-Activated Kinase Inhibitor, Normalizes Dysregulation In Alpha1-Adrenergic Receptor-Induced Contraction Of Lyon Hypertensive Rat Artery Smooth Muscle., Maria Regina Freitas, Masumi Eto, Jason A Kirkbride, Christa Schott, Jean Sassard, Jean-Claude Stoclet

Department of Molecular Physiology and Biophysics Faculty Papers

RhoA-activated kinase (ROK) is involved in the disorders of smooth muscle contraction found in hypertension model animals and patients. We examined whether the alpha1-adrenergic receptor agonist-induced ROK signal is perturbed in resistance small mesentery artery (SMA) of Lyon genetically hypertensive (LH) rats, using a ROK antagonist, Y27632. Smooth muscle strips of SMA and aorta were isolated from LH and Lyon normotensive (LN) rats. After Ca(2+)-depletion and pre-treatment with phenylephrine (PE), smooth muscle contraction was induced by serial additions of CaCl(2). In LH SMA Ca(2+) permeated cells to a lesser extent as compared with LN SMA, while CaCl(2)-induced contraction of LH …

Lapd Is A Bis-(3′,5′)-Cyclic Dimeric Gmp-Binding Protein That Regulates Surface Attachment By Pseudomonas Fluorescens Pf0–1, Peter D. Newell, Russell D. Monds, George A. O'Toole

Dartmouth Scholarship

The second messenger cyclic dimeric GMP (c-di-GMP) regulates surface attachment and biofilm formation by many bacteria. For Pseudomonas fluorescens Pf0-1, c-di-GMP impacts the secretion and localization of the adhesin LapA, which is absolutely required for stable surface attachment and biofilm formation by this bacterium. In this study we characterize LapD, a unique c-di-GMP effector protein that controls biofilm formation by communicating intracellular c-di-GMP levels to the membrane-localized attachment machinery via its periplasmic domain. LapD contains degenerate and enzymatically inactive diguanylate cyclase and c-di-GMP phosphodiesterase (EAL) domains and binds to c-di-GMP through a degenerate EAL domain. We present evidence that LapD …

Paracrine Sonic Hedgehog Signalling By Prostate Cancer Cells Induces Osteoblast Differentiation, Samantha M Zunich, Taneka Douglas, Maria Valdovinos, Tiffany Chang

Dartmouth Scholarship

Sonic hedgehog (Shh) and components of its signalling pathway have been identified in human prostate carcinoma and increased levels of their expression appear to correlate with disease progression and metastasis. The mechanism through which Shh signalling could promote metastasis in bone, the most common site for prostate carcinoma metastasis, has not yet been investigated. The present study determined the effect of Shh signalling between prostate cancer cells and pre-osteoblasts on osteoblast differentiation, a requisite process for new bone formation that characterizes prostate carcinoma metastasis.

Arteriogenic Revascularization Does Not Induce Vascular Function Impairment, Matthew David Yocum

Master's Theses

Functional hyperemia and arteriolar vasodilation are impaired with chronic ischemia. We sought to examine the impact of chronic ischemia on collateral artery function. For this we used two hindlimb ischemia models to dissect the impact of different repair processes on collateral function. Ligation of the femoral artery increases shear stress in the muscular branch and results in outward remodeling and arteriogenesis. In contrast, resection of the femoral artery proximal to the muscular branch induces blood flow divergence and neutral remodeling along with expectedly greater hypoxia and inflammation. On day 14 after each surgery the diameter of the muscular branch was …

Positional Information Generated By Spatially Distributed Signaling Cascades., Javier Muñoz-García, Zoltan Neufeld, Boris N Kholodenko

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

The temporal and stationary behavior of protein modification cascades has been extensively studied, yet little is known about the spatial aspects of signal propagation. We have previously shown that the spatial separation of opposing enzymes, such as a kinase and a phosphatase, creates signaling activity gradients. Here we show under what conditions signals stall in the space or robustly propagate through spatially distributed signaling cascades. Robust signal propagation results in activity gradients with long plateaus, which abruptly decay at successive spatial locations. We derive an approximate analytical solution that relates the maximal amplitude and propagation length of each activation profile …

Lymphocyte Proliferation To Mycobacterial Antigens Is Detectable Across A Spectrum Of Hiv-Associated Tuberculosis, Timothy Lahey, Mecky Matee, Lillian Mtei, Muhammad Bakari, Kisali Pallangyo, C Fordham Von Reyn

Dartmouth Scholarship

Background:

Identifying novel TB diagnostics is a major public health priority. We explored the diagnostic characteristics of antimycobacterial lymphocyte proliferation assays (LPA) in HIV-infected subjects with latent or active TB.

Methods:

HIV-infected subjects with bacille Calmette Guérin (BCG) scars and CD4 counts ≥ 200 cells/mm³ entering a TB booster vaccine trial in Tanzania had baseline in vivo and in vitro immune tests performed: tuberculin skin tests (TST), LPA and five day assays of interferon gamma (IFN-γ) release. Assay antigens were early secreted antigenic target 6 (ESAT-6), antigen 85 (Ag85), and Mycobacterium tuberculosis whole cell lysate (WCL). Subjects were screened …

At Risk? Exploring The Relationship Between Hiv/Aids-Related Knowledge And Risky Sexual Behavior In Jamaica, Christine Chung

Award Winning Geography Papers

Using the 2004 Knowledge, Attitudes, Behaviour and Practices (KABP) national survey, this research investigates factors contributing to HIV/AIDS-related risky sexual behavior in Jamaica, using the theoretical underpinnings behind the concept of “risk” to elucidate the relative vulnerability of different demographic groups. In particular, how is risk defined and by whom, and how does this shape the risk environment for HIV/AIDS. The social construction of “risk” is explored as an act of translation of science, whose formalized and institutionalized meanings do not always match up to the individual’s perception of personal risk to HIV/AIDS. The disjunction between knowledge and actual behavioral …

Dna Instability In Replicating Huntington's Disease Lymphoblasts, Milena Cannella, Vittorio Maglione, Tiziana Martino, Giuseppe Ragona, Luigi Frati, Guo-Min Li, Ferdinando Squitieri

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: The expanded CAG repeat in the Huntington's disease (HD) gene may display tissue-specific variability (e.g. triplet mosaicism) in repeat length, the longest mutations involving mitotic (germ and glial cells) and postmitotic (neurons) cells. What contributes to the triplet mutability underlying the development of HD nevertheless remains unknown. We investigated whether, besides the increased DNA instability documented in postmitotic neurons, possible environmental and genetic mechanisms, related to cell replication, may concur to determine CAG repeat mutability. To test this hypothesis we used, as a model, cultured HD patients' lymphoblasts with various CAG repeat lengths.

RESULTS: Although most lymphoblastoid cell lines …

The P53-Induced Siva-1 Plays A Significant Role In Cisplatin-Mediated Apoptosis, John L. Barkinge, Radhika Gudi, Hawkins Sarah, Fei Chu, Alip Borthakur, Bellur S. Prabhakar

Clinical & Translational Sciences

Background: The pro-apoptotic protein Siva-1 functions in both extrinsic and intrinsic cell death signaling; however, the exact contribution of the endogenous Siva-1 to DNA damage-induced apoptosis is unclear. Using cisplatin, a chemotherapeutic drug, to induce DNA damage and cell death, we determined the role of Siva-1.

Methods: Cisplatin treated HCT116 colorectal carcinoma cells (p53+/+ and -/-) were used in the study. With the help of recombinant lentivirus that can express siSiva (siRNA that specifi cally targets Siva-1), we also generated Siva-1 knockdown HCT116 cells. Apoptosis was determined by tetramethyl rhodamine methyl ester (TMRM) staining and propidium iodide (PI) staining.

Results: …

Interconnections Between Sigma B, Agr, And Proteolytic Activity In Staphylococcus Aureus Biofilm Maturation, Katherine J. Lauderdale, Blaise R. Boles, Ambrose L. Cheung, Alexander R. Horswill

Dartmouth Scholarship

Staphylococcus aureus is a proficient biofilm former on host tissues and medical implants. We mutagenized S. aureus strain SH1000 to identify loci essential for ica-independent mechanisms of biofilm maturation and identified multiple insertions in the rsbUVW-sigB operon. Following construction and characterization of a sigB deletion, we determined that the biofilm phenotype was due to a lack of sigma factor B (SigB) activity. The phenotype was conserved in a sigB mutant of USA300 strain LAC, a well-studied community-associated methicillin-resistant S. aureus isolate. We determined that agr RNAIII levels were elevated in the sigB mutants, and high levels of RNAIII expression are …

Nonrigid Registration Of Three-Dimensional Ultrasound And Magnetic Resonance Images Of The Carotid Arteries, Nuwan D Nanayakkara, Bernard Chiu, Abbas Samani, J David Spence, Jagath Samarabandu, Grace Parraga, Aaron Fenster

Medical Biophysics Publications

Atherosclerosis at the carotid bifurcation can result in cerebral emboli, which in turn can block the blood supply to the brain causing ischemic strokes. Noninvasive imaging tools that better characterize arterial wall, and atherosclerotic plaque structure and composition may help to determine the factors which lead to the development of unstable lesions, and identify patients at risk of plaque disruption and stroke. Carotid magnetic resonance (MR) imaging allows for the characterization of carotid vessel wall and plaque composition, the characterization of normal and pathological arterial wall, the quantification of plaque size, and the detection of plaque integrity. On the other …

Leptospira Interrogans Induces Apoptosis In Macrophages Via Caspase-8- And -3-Dependent Pathways, Dandan Jin, David M. Ojcius, Dexter Sun, Haiyan Dong, Yihui Luo, Yafei Mao, Jie Yan

All Dugoni School of Dentistry Faculty Articles

Apoptosis of host cells plays an important role in modulating the pathogenesis of many infectious diseases. It has been reported that Leptospira interrogans, the causal agent of leptospirosis, induces apoptosis in macrophages and hepatocytes. However, the molecular mechanisms responsible for host cell death remained largely unknown. Here we demonstrate that L. interrogans induced apoptosis in a macrophage-like cell line, J774A.1, and primary murine macrophages in a time- and dose-dependent manner. Apoptosis was associated with the activation of cysteine aspartic acid-specific proteases (caspase-3, caspase-6, and caspase-8), the increased expression of Fas-associated death domain (FADD), and the cleavage of the caspase substrates …

Corr4a And Vrt325 Do Not Reduce The Inflammatory Response To P. Aeruginosa In Human Cystic Fibrosis Airway Epithelial Cells, Laleh Talebian, Bonita Coutermarsh, Jacqueline Y. Channon, Bruce A. Stanton

Dartmouth Scholarship

P. aeruginosa chronically colonizes the lung in CF patients and elicits a proinflammatory response. Excessive secretion of IL-6 and IL-8 by CF airway cells in response to P. aeruginosa infection in the CF airway is though to contribute to lung injury. Accordingly, the goal of this study was to test the hypothesis that Corr4a and VRT325, investigational compounds that increase ΔF508-CFTR mediated Cl⁻ secretion in human CF airway cells, reduce the pro-inflammatory response to P. aeruginosa.

Effects Of Microgravity On Cancer Stem Cells Cultured In A Nasa Developed Bioreactor: Chemotherapeutic Implications., Sarah Elizabeth Daron Kelly

Theses, Dissertations and Capstones

The purpose of this study was to investigate the effects of simulated microgravity on cancer cell growth. Simulated microgravity is a condition in which cells are in constant free-fall and in which they are able to grow suspended without the shear and stress. Microgravity allows for important insights into the cellular mechanism and may be key in understanding why some cells thrive in this condition and others go into apoptosis. Cancer stem cells (CSCs) are considered a subset of the bulk tumor responsible for initiating and maintaining cancer. SAOS-2 is a human bone cancer cell line which consists of a …

Fusion, 2009, George Washington University, William H. Beaumont Medical Research Honor Society

Fusion

No abstract provided.

Reduced Genomic Potential For Secreted Plant Cell-Wall-Degrading Enzymes In The Ectomycorrhizal Fungus Amanita Bisporigera, Based On The Secretome Of Trichoderma Reesei, Subashini Nagendran, Heather E. Hallen-Adams, Janet M. Paper, Nighat Aslam, Jonathan D. Walton

Heather Hallen-Adams Publications

Based on the analysis of its genome sequence, the ectomycorrhizal (ECM) basidiomycetous fungus Laccaria bicolor was shown to be lacking many of the major classes of secreted enzymes that depolymerize plant cell wall polysaccharides. To test whether this is also a feature of other ECM fungi, we searched a survey genome database of Amanita bisporigera with the proteins found in the secretome of Trichoderma reesei (syn. Hypocrea jecorina), a biochemically well-characterized industrial fungus. Additional proteins were also used as queries to compensate for major groups of cell-wall-degrading enzymes lacking in the secretome of T. reesei and to substantiate conclusions …

Regulation Of Alginate Production Of Pseudomonas Aeruginosa Pseudomonas Aeruginosa, Fredrick Heath Damron

Theses, Dissertations and Capstones

Pseudomonas aeruginosa (P.a.) is a major threat to the health and well being of a person living with cystic fibrosis (CF). P.a. is capable of conversion to mucoidy or alginate overproducing phenotype. Mucoidy facilitates the chronic infection of P.a. infection in the CF lung. Mutations in the anti-sigma factor mucA, result in activation of the sigma factor AlgU which promotes expression of alginate through the alginate biosynthetic operon. However, P.a. can produce alginate independent of mucA mutation via a mechanism known as regulated proteolysis. Proteases AlgW and MucP can degrade MucA to liberate and activate AlgU. In this dissertation, two …