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Animal Carcinogenicity Studies: 2. Obstacles To Extrapolation Of Data To Humans, Andrew Knight, Jarrod Bailey, Jonathan Balcombe

Experimentation Collection

Due to limited human exposure data, risk classification and the consequent regulation of exposure to potential carcinogens has conventionally relied mainly upon animal tests. However, several investigations have revealed animal carcinogenicity data to be lacking in human predictivity. To investigate the reasons for this, we surveyed 160 chemicals possessing animal but not human exposure data within the US Environmental Protection Agency chemicals database, but which had received human carcinogenicity assessments by 1 January 2004. We discovered the use of a wide variety of species, with rodents predominating, and of a wide variety of routes of administration, and that there were …

Animal Carcinogenicity Studies: 3. Alternatives To The Bioassay, Andrew Knight, Jarrod Bailey, Jonathan Balcombe

Experimentation Collection

Conventional animal carcinogenicity tests take around three years to design, conduct and interpret. Consequently, only a tiny fraction of the thousands of industrial chemicals currently in use have been tested for carcinogenicity. Despite the costs of hundreds of millions of dollars and millions of skilled personnel hours, as well as millions of animal lives, several investigations have revealed that animal carcinogenicity data lack human specificity (i.e. the ability to identify human non-carcinogens), which severely limits the human predictivity of the bioassay. This is due to the scientific inadequacies of many carcinogenicity bioassays, and numerous serious biological obstacles, which render profoundly …

Keeping Their Options Open: Acute Versus Persistent Infections, S. Furukawa, S. L. Kuchma, G. A. O'Toole

Dartmouth Scholarship

No abstract provided.

Neuromechanics Of Coordination During Swallowing In Aplysia Californica, Hui Ye, Douglas W. Morton, Hillel J. Chiel

Faculty Scholarship

Bernstein (1967) hypothesized that preparation of the periphery was crucial for correct responses to motor output. To test this hypothesis in a behaving animal, we examined the roles of two identified motor neurons, B7 and B8, which contribute to feeding behavior in the marine mollusk Aplysia californica. Neuron B7 innervates a hinge muscle and has no overt behavioral effect during smaller-amplitude (type A) swallows, because the hinge muscle is too short to exert force. Neuron B8 activates a muscle (I4) that acts solely to grasp material during type A swallows. During larger-amplitude (type B) swallows, the behavioral actions of both …

Transcriptome Signature Of Virulent And Attenuated Pseudorabies Virus-Infected Rodent Brain, Christina Paulus, Patricia J. Sollars, Gary E. Pickard, Lynn W. Enquist

School of Veterinary and Biomedical Sciences: Faculty Publications

Mammalian alphaherpesviruses normally establish latent infections in ganglia of the peripheral nervous system in their natural hosts. Occasionally, however, these viruses spread to the central nervous system (CNS), where they cause damaging, often fatal, infections. Attenuated alphaherpesvirus derivatives have been used extensively as neuronal circuit tracers in a variety of animal models. Their circuit-specific spread provides a unique paradigm to study the local and global CNS response to infection. Thus, we systematically analyzed the host gene expression profile after acute pseudorabies virus (PRV) infection of the CNS using Affymetrix GeneChip technology. Rats were injected intraocularly with one of three selected …

Treponema Denticola In Disseminating Endodontic Infections, F. Foschi, Jacques Izard, H. Sasaki, V. Sambri, C. Prati, R. Müller, P. Stashenko

Department of Food Science and Technology: Faculty Publications

Treponema denticola is a consensus periodontal pathogen that has recently been associated with endodontic pathology. In this study, the effect of mono-infection of the dental pulp with T. denticola and with polymicrobial “red-complex” organisms (RC) (Porphyromonas gingivalis, Tannerella forsythia, and T. denticola) in inducing disseminating infections in wild-type (WT) and severe-combined-immunodeficiency (SCID) mice was analyzed. After 21 days, a high incidence (5/10) of orofacial abscesses was observed in SCID mice mono-infected with T. denticola, whereas abscesses were rare in SCID mice infected with the red-complex organisms or in wild-type mice. Splenomegaly was …

Do Cd1-Restricted T Cells Contribute To Antibody-Mediated Immunity Against Mycobacterium Tuberculosis?, Mark L. Lang, Aharona Glatman-Freedman

Dartmouth Scholarship

No abstract provided.

Antisense Inhibition Of Cyclin D1 Expression Is Equivalent To Flavopiridol For Radiosensitization Of Zebrafish Embryos, Mary Frances Mcaleer, Kevin T. Duffy, William R. Davidson, Gabor Kari, Adam P. Dicker, Ulrich Rodeck, Eric Wickstrom

Department of Biochemistry and Molecular Biology Faculty Papers

Purpose: Flavopiridol, a small molecule pan-cyclin inhibitor, has been shown to enhance the radiation response of tumor cells both in vitro and in vivo. The clinical utility of flavopiridol, however, is limited by toxicity, previously attributed to pleiotropic inhibitory effects on several targets affecting multiple signal transduction pathways. Here we utilized zebrafish embryos to investigate radiosensitizing effects of flavopiridol in normal tissues.

Methods and Materials: Zebrafish embryos at the 1-4 cell stage were treated with 500 nM flavopiridol or injected with 0.5 pmol antisense hydroxylprolyl-phosphono nucleic acid oligomers to reduce cyclin D1 expression, then subjected to ionizing radiation (IR) or …

A Domain-Oriented Approach To The Reduction Of Combinatorial Complexity In Signal Transduction Networks, Holger Conzelmann, Julio Saez-Rodriguez, Thomas Sauter, Boris N. Kholodenko Phd, Dsci, Ernst D. Gilles

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Background:

Receptors and scaffold proteins possess a number of distinct domains and bind multiple partners. A common problem in modeling signaling systems arises from a combinatorial explosion of different states generated by feasible molecular species. The number of possible species grows exponentially with the number of different docking sites and can easily reach several millions. Models accounting for this combinatorial variety become impractical for many applications.

Results:

Our results show that under realistic assumptions on domain interactions, the dynamics of signaling pathways can be exactly described by reduced, hierarchically structured models. The method presented here provides a rigorous way to …

Clinical Perspectives Of Emerging Pathogens In Bleeding Disorders, Jamie Siegel

Department of Medicine Faculty Papers

As a result of immunological and nucleic-acid screening of plasma donations for transfusion-transmissible viruses, and the incorporation of viral reduction processes during plasma fractionation, coagulation-factor concentrates (CFC) are now judged safe in terms of many known infectious agents, including hepatitis B and C viruses, HIV, and human T-cell lymphotropic virus. However, emerging pathogens could pose future threats, particularly those with blood-borne stages that are resistant to viral-inactivation steps in the manufacturing process, such as non-lipid-coated viruses. As outlined in this Review, better understanding of infectious diseases allows challenges from newly described agents of potential concern in the future to be …

The Inflammatory And Normal Transcriptome Of Mouse Bladder Detrusor And Mucosa, Marcia R. Saban, Helen L. Hellmich, Mary Turner, Ngoc-Bich Nguyen, Rajanikanth Vadigepalli, David W. Dyer, Robert E. Hurst, Michael Centola, Ricardo Saban

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Background

An organ such as the bladder consists of complex, interacting set of tissues and cells. Inflammation has been implicated in every major disease of the bladder, including cancer, interstitial cystitis, and infection. However, scanty is the information about individual detrusor and urothelium transcriptomes in response to inflammation. Here, we used suppression subtractive hybridizations (SSH) to determine bladder tissue- and disease-specific genes and transcriptional regulatory elements (TRE)s. Unique TREs and genes were assembled into putative networks.

Results

It was found that the control bladder mucosa presented regulatory elements driving genes such as myosin light chain phosphatase and calponin 1 that …

Competition Between The Dna Unwinding And Strand Pairing Activities Of The Werner And Bloom Syndrome Proteins, Amrita Machwe, Enerlyn M. Lozada, Liren Xiao, David K. Orren

Toxicology and Cancer Biology Faculty Publications

BACKGROUND: The premature aging and cancer-prone Werner and Bloom syndromes are caused by defects in the RecQ helicase enzymes WRN and BLM, respectively. Recently, both WRN and BLM (as well as several other RecQ members) have been shown to possess a strand annealing activity in addition to the requisite DNA unwinding activity. Since an annealing function would appear to directly oppose the action of a helicase, we have examined in this study the dynamic equilibrium between unwinding and annealing mediated by either WRN or BLM.

RESULTS: Our investigation into the competition between annealing and unwinding demonstrates that, under standard reaction …

A Mechanistic Study Of The Protective Effects Of S-Adenosyl-L-Methionine Against Hepatotoxicity Of Acetaminophen, Marcus V. Terneus Jr.

Theses, Dissertations and Capstones

Hepatic toxicity is known to be associated with excessive doses of the over-the-counter analgesic, acetaminophen (APAP). APAP overdose is the leading cause of drug-induced liver failure in the United States. APAP hepatotoxicity is dependent on the biotransformation of APAP by cytochrome P450 to the toxic metabolite, N-acetyl-p-benzoquinone imine (NAPQI). APAP, when taken in excessive doses, can lead to severe liver damage with the potential to progress to liver failure. Despite substantial efforts in past studies, the mechanism by which APAP induces such damaging effects is not completely understood. Recent discoveries suggest that glutathione (GSH) depletion, protein alkylation and reactive metabolite …

Protein Kinase C Activity In Mouse Eggs Regulates Gamete Membrane Interaction, Hiroto Akabane

Theses, Dissertations and Capstones

Every mammalian life develops from one cell after fertilization of an egg by the sperm. The molecular pathways governing this event are still poorly understood. Numerous reports indicate that mammalian eggs highly express various protein kinase C (PKC) isoforms. Accordingly, we hypothesize that PKC activity in the egg plays an important role during egg-sperm membrane binding and fusion. In this study, we tested our hypothesis in mouse gametes using two types of PKC inhibitors (calphostin c and staurosporine) and the typical PKC activator, phorbol ester 12-tetradecanoylphorbol-13 acetate (PMA). After treatment with the individual drug, eggs were inseminated with sperm. The …

Thimerosal-Induced Neuritoxicity: Apoptosis Occurs Through A Mitochondrial-Mediated Pathway Via The Jnk Signaling Pathway, Michelle L. Herdman

Theses, Dissertations and Capstones

Thimerosal is an organic mercurial containing an ethylmercury moiety attached to the sulfur atom of thiosalicylate. Since the 1930s, thimerosal has been used as an antiseptic and a preservative in a wide variety of products, including medicinal preparations administered to children and pregnant women. Past exposures to mercurials have indicated that mercury is a neurotoxin, and can also affect the kidney, skin, eyes, and immune system. Additionally, fetuses exposed to mercurials are more susceptible to toxicity because the nervous system is continuously developing. However, despite its widespread use, thimerosal was only studied on a limited basis until the end of …

Regulation Of Biofilm Formation Of Pseudomonas Aeruginosa, Nathaniel Edwards Head

Theses, Dissertations and Capstones

Cystic fibrosis (CF) is the most common, autosomal recessive lethal genetic disease in the Caucasian population, resulting from a malfunctioned cystic fibrosis transmembrane conductance regulator (CFTR) and leading to bacterial lung infections. P. aeruginosa, an opportunistic pathogen, establishes a chronic infection in CF with a phenotype of overproduction of an exopolysaccharide (alginate) due to host-directed mutagenesis. While free-floating planktonic bacteria can be properly cleared from the CF lung, P. aeruginosa, along with alginate production, establishes an infection in the form of a biofilm which supports its survival in nature and in vivo. As a result, genomic structure, …

Characterization Of The Dna-Binding Properties Of Silent Information Regulator 3 Protein, Cotteka Nichisha Johnson

Theses, Dissertations and Capstones

The eukaryotic genome is organized into distinct domains with discrete regulatory potential, influenced by the variation in local chromatin structure. An example of chromatin-mediated consequences on gene expression is mating type determination of yeast Saccharomyces cerevisiae, which depends on silencing of specific gene cassettes. Silencing in yeast involves key proteins, amongst which the Silent Information Regulator (Sir) proteins are essential. Sir1p, Sir2p, and Sir4p are recruited to nucleate silencing events, while Sir3p serves as the pivotal factor in spreading the silent state. This investigation characterizes the DNA binding properties of Sir3p using DNA fragments with varying degrees of inherent flexibility, …

Linking Ligand-Induced Alterations In Androgen Receptor Structure To Differential Gene Expression: A First Step In The Rational Design Of Selective Androgen Receptor Modulators, Dmitri Kazmin, Tatiana Prytkova, C. Edgar Cook, Russell Wolfinger, Tzu-Ming Chu, David Beratan, J. D. Norris, Ching-Yi Chang, Donald P. Mcdonnell

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We have previously identified a family of novel androgen receptor (AR) ligands that, upon binding, enable AR to adopt structures distinct from that observed in the presence of canonical agonists. In this report, we describe the use of these compounds to establish a relationship between AR structure and biological activity with a view to defining a rational approach with which to identify useful selective AR modulators. To this end, we used combinatorial peptide phage display coupled with molecular dynamic structure analysis to identify the surfaces on AR that are exposed specifically in the presence of selected AR ligands. Subsequently, we …

Monoclonal Antibodies To Distinct Regions Of Human Myelin Proteolipid Protein Simultaneously Recognize Central Nervous System Myelin And Neurons Of Many Vertebrate Species, Edward A. Greenfield, Jay Reddy, Andrew Lees, Charissa A. Dyer, Omanand Koul, Khuong Nguyen, Shannon Bell, Nasim Kassam, Julian Hinojoza, Mary Jane Eaton, Marjorie B. Lees, Vijay K. Kuchroo, Raymond A. Sobel

Jay Reddy Publications

Myelin proteolipid protein (PLP), the major protein of mammalian CNS myelin, is a member of the proteolipid gene family (pgf). It is an evolutionarily conserved polytopic integral membrane protein and a potential autoantigen in multiple sclerosis (MS). To analyze antibody recognition of PLP epitopes in situ, monoclonal antibodies (mAbs) specific for different regions of human PLP (50–69, 100–123, 139–151, 178–191, 200–219, 264–276) were generated and used to immunostain CNS tissues of representative vertebrates. mAbs to each region recognized whole human PLP on Western blots; the anti-100–123 mAb did not recognize DM-20, the PLP isoform that lacks residues 116–150. All of …

Diverse Roles Of Pkcα In Vascular Smooth Muscle Contraction, Ava Caudill Dykes

Theses, Dissertations and Capstones

A complete understanding of the mechanisms underlying smooth muscle contractility has proven elusive due to the many interacting factors thought to influence contractile behavior in this muscle type. One such factor, protein kinase Cα (PKCα), is proposed to play a central role in both the activation and modulation of smooth muscle contraction. PKCα is activated through a G-protein coupled receptor and is subsequently translocated to its site of action. Although the mechanisms regulating PKCα site specific translocation are not completely understood, it is thought that this process is essential for PKCα specificity of action within the cell. In chapter II …

A Database And Tool, Im Browser, For Exploring And Integrating Emerging Gene And Protein Interaction Data For Drosophila, Svetlana Pacifico, Guozhen Liu, Stephen Guest, Jodi R. Parrish, Farshad Fotouhi, Russell L. Finley Jr

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Biological processes are mediated by networks of interacting genes and proteins. Efforts to map and understand these networks are resulting in the proliferation of interaction data derived from both experimental and computational techniques for a number of organisms. The volume of this data combined with the variety of specific forms it can take has created a need for comprehensive databases that include all of the available data sets, and for exploration tools to facilitate data integration and analysis. One powerful paradigm for the navigation and analysis of interaction data is an interaction graph or map that represents proteins …

Production Of Il-16 Correlates With Cd4+ Th1 Inflammation And Phosphorylation Of Axonal Cytoskeleton In Multiple Sclerosis Lesions, Dusanka S. Skundric, Juan Cai, William W. Cruikshank, Djordje Gveric

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

Multiple sclerosis (MS) is a central nervous system-specific autoimmune, demyelinating and neurodegenerative disease. Infiltration of lesions by autoaggressive, myelin-specific CD4+Th1 cells correlates with clinical manifestations of disease. The cytokine IL-16 is a CD4+ T cell-specific chemoattractant that is biased towards CD4+ Th1 cells. IL-16 precursor is constitutively expressed in lymphocytes and during CD4+ T cell activation; active caspase-3 cleaves and releases C-terminal bioactive IL-16. Previously, we used an animal model of MS to demonstrate an important role for IL-16 in regulation of autoimmune inflammation and subsequent axonal damage. This role of IL-16 in MS is largely unexplored. Here …

Counseling Patients Exposed To Ionizing Radiation During Pregnancy, Robert L. Brent

The Selected Works of Robert Brent

Health physicists and knowledgeable clinicians have the responsibility to counsel women of reproductive age about the reproductive risks of ionizing radiation exposure before conception or during pregnancy. It is important to realize that lay individuals have many misconceptions about the reproductive risks of ionizing radiation. Many patients who have already had or will undergo some type of radiological test are apprehensive about the reproductive and developmental risks of diagnostic radiological procedures. Epidemiological studies and animal studies indicate that high exposures of ionizing radiation can cause miscarriage, congenital malformations, growth retardation, stillbirth, and cancer. With the exception of cancer, there are …

Health Professions Division Catalog 2006-2007, Nova Southeastern University

Health Professions Divisions Course Catalogs and Course Descriptions

No abstract provided.

Stromal Haze, Myofibroblasts, And Surface Irregularity After Prk, Marcelo V. Netto, Rajiv R. Mohan, Sunilima Sinha, Ajay Sharma, William Dupps, Steven E. Wilson

Pharmacy Faculty Articles and Research

The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze.

Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups[.]

Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr …

A Group M Consensus Envelope Glycoprotein Induces Antibodies That Neutralize Subsets Of Subtype B And C Hiv-1 Primary Viruses, Hua-Xin Lin, Laura L. Sutherland, Shi-Mao Xia, Mary E. Brock, Richard M. Scearce, Stacie Vanleeuwen, S. Munir Alam, Mildred Mcadams, Eric A. Weaver, Zenaido T. Camacho, Ben-Jiang Ma, Yingying Li, Julie M. Decker, Gary J. Nabel, David C. Montefiori, Beatrice H. Hahn, Bette T. Korber, Feng Gao, Barton F. Haynes

Nebraska Center for Virology: Faculty Publications

HIV-1 subtype C is the most common HIV-1 group M subtype in Africa and many parts of Asia. However, to date HIV-1 vaccine candidate immunogens have not induced potent and broadly neutralizing antibodies against subtype C primary isolates. We have used a centralized gene strategy to address HIV-1 diversity, and generated a group M consensus envelope gene with shortened consensus variable loops (CON-S) for comparative studies with wildtype (WT) Env immunogens. Our results indicate that the consensus HIV-1 group M CON-S Env elicited cross-subtype neutralizing antibodies of similar or greater breadth and titer than the WT Envs tested, indicating the …

Simultaneous Measurement Of Water Volume And Ph In Single Cells Using Bcecf And Fluorescence Imaging Microscopy, Francisco J. Alvarez-Leefmans, José J. Herrera-Pérez, Martín S. Márquez, Victor M. Blanco

Pharmacology and Toxicology Faculty Publications

Regulation and maintenance of cell water volume and intracellular pH (pH_i) are vital functions that are interdependent; cell volume regulation affects, and is in turn affected by, changes in pH_i. Disruption of either function underlies various pathologies. To study the interaction and kinetics of these two mechanisms, we developed and validated a quantitative fluorescence imaging microscopy method to measure simultaneous changes in pH_i and volume in single cells loaded with the fluorescent probe BCECF. CWV is measured at the excitation isosbestic wavelength, whereas pH_iis determined ratiometrically. The method has a time resolution of …

Rapid Determination Of Reduced And Oxidized Glutathione Levels Using A New Thiol-Masking Reagent And The Enzymatic Recycling Method: Application To The Rat Liver And Bile Samples, Imam H. Shaik, Reza Mehvar

Pharmacy Faculty Articles and Research

A microtiter plate assay for quantitation of reduced (GSH) and oxidized (GSSG) glutathione in the rat liver tissue and bile is described. The assay is based on the established enzymatic recycling method and a new thiol-masking reagent, 1-methyl-4-vinyl-pyridinium trifluoromethane sulfonate (M4VP). Samples were first processed by homogenization with (liver) or addition of (bile) sulfosalicylic acid. The total glutathione and GSSG were then determined before and after rapid (>= 2 min) and efficient (100%) masking of the GSH content of the samples with M4VP followed by the enzymatic recycling assay. The percentages of error and coefficient of variation of the …

Transposon Disruption Of The Complex I Nadh Oxidoreductase Gene (Snod) In Staphylococcus Aureus Is Associated With Reduced Susceptibility To The Microbicidal Activity Of Thrombin-Induced Platelet Microbicidal Protein 1, Arnold S. Bayer, Peter Mcnamara, Michael R. Yeaman, Natalie Lucindo, Tiffanny Jones, Ambrose L. Cheung

Dartmouth Scholarship

The cationic molecule thrombin-induced platelet microbicidal protein 1 (tPMP-1) exerts potent activity against Staphylococcus aureus. We previously reported that a Tn551 S. aureus transposon mutant, ISP479R, and two bacteriophage back-transductants, TxA and TxB, exhibit reduced in vitro susceptibility to tPMP-1 (tPMP-1(r)) compared to the parental strain, ISP479C (V. Dhawan, M. R. Yeaman, A. L. Cheung, E. Kim, P. M. Sullam, and A. S. Bayer, Infect. Immun. 65:3293-3299, 1997). In the current study, the genetic basis for tPMP-1(r) in these mutants was identified. GenBank homology searches using sequence corresponding to chromosomal DNA flanking Tn551 mutant strains showed that the fourth gene …

Potential Of Vibrational Spectroscopy In The Diagnosis Of Human Tumours., Eoghan O'Faolain

Doctoral

Just fewer than 20,000 people are annually diagnosed with some form of cancer in Ireland and one in three people are likely to contract some form of cancer by age 74. With the number of cases increasing at an annual rate of 2%, the early detection and treatment of cancer is becoming increasingly important. Both IR and Raman spectroscopy offer the potential for real time, quantitative detection of cancer and even precancer. This study investigates the potential of Raman and Fourier transform infrared, both benchtop and synchrotron spectroscopies for the detection of cervical cancer. The tissue was classified and its …