Medicine and Health Sciences Commons^™

Improving Quantitative Treatment Response Monitoring With Deformable Image Registration, Blake A. Cannon

Dissertations and Theses (Open Access)

Quantitative imaging with 18F-FDG PET/CT has the potential to provide an in vivo assessment of response to radiotherapy (RT). However, comparing tissue tracer uptake in longitudinal studies is often confounded by variations in patient setup and potential treatment induced gross anatomic changes. These variations make true response monitoring for the same anatomic volume a challenge, not only for tumors, but also for normal organs-at-risk (OAR). The central hypothesis of this study is that more accurate image registration will lead to improved quantitation of tissue response to RT with 18F-FDG PET/CT. Employing an in-house developed “demons” based deformable image registration algorithm, …

Defining The Role Of Il-15 Trans-Presentation By Distinct Cell-Types During The Development And Homeostasis Of Natural Killer And Invariant Natural Killer T Cells, Eliseo F. Castillo

Dissertations and Theses (Open Access)

The immuno-regulatory functions displayed by NK and iNKT cells have highlighted their importance as key lymphocytes involved in innate and adaptive immunity. Therefore, understanding the dynamics influencing the generation of NK and iNKT cells is extremely important. IL-15 has been shown to provide a critical signal throughout the development and homeostasis of NK and iNKT cells; however, the cellular source of IL-15 has remained unclear. In this investigation, I provide evidence that the cell-type providing IL-15 to NK and iNKT cells via trans-presentation is determined by the tissue site and the maturation status of NK and iNKT cells. For NK …

Thoracic Target Volume Delineation Using Various Maximum-Intensity Projection Computed To Mography Image Sets For Stereotactic Body Radiation Therapy, David A. Zamora

Dissertations and Theses (Open Access)

The motion of lung tumors during respiration makes the accurate delivery of radiation therapy to the thorax difficult because it increases the uncertainty of target position. The adoption of four-dimensional computed tomography (4D-CT) has allowed us to determine how a tumor moves with respiration for each individual patient. Using information acquired during a 4D-CT scan, we can define the target, visualize motion, and calculate dose during the planning phase of the radiotherapy process. One image data set that can be created from the 4D-CT acquisition is the maximum-intensity projection (MIP). The MIP can be used as a starting point to …

A Smac Mimetic Reduces Tnf Related Apoptosis Inducing Ligand (Trail)-Induced Invasion And Metastasis Of Cholangiocarcinoma Cells., Christian D. Fingas, Boris R.A. Blechacz, Rory L. Smoot, Maria E. Guicciardi, Justin L. Mott, Steve F. Bronk, Nathan W. Werneburg, Alphonse E. Sirica, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

UNLABELLED: Cholangiocarcinoma (CCA) cells paradoxically express tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a death ligand that, failing to kill CCA cells, instead promotes their tumorigenicity and especially the metastatic behaviors of cell migration and invasion. Second mitochondria-derived activator of caspase (smac) mimetics are promising cancer therapeutic agents that enhance proapoptotic death receptor signaling by causing cellular degradation of inhibitor of apoptosis (IAP) proteins. Our aim was to examine the in vitro and in vivo effects of the smac mimetic JP1584 in CCA. Despite JP1584-mediated loss of cellular inhibitor of apoptosis-1 (cIAP-1) and cIAP-2, TRAIL failed to induce apoptosis in KMCH-1, …

Emergency Reversal Of Antiplatelet Agents In Patients Presenting With An Intracranial Hemorrhage: A Clinical Review, Peter G. Campbell, Md, Anish Sen, Bs, Sanjay Yadla, Md, Pascal Jabbour, Md, Jack Jallo, Md, Phd

Department of Neurosurgery Faculty Papers

Abstract

Objective: Prehospital use of antiplatelet agents has been associated with an increased risk for ICH as well as a secondary increase in ICH volume after the initial hemorrhage. Strategies to reestablish platelet aggregation are used in clinical practice, but without any established guidelines or recommendations. This article serves to evaluate the literature regarding “reversal” of antiplatelet agents in neurosurgical populations.

Methods: PUBMED and MEDLINE databases were searched for publications from 1966 to 2009 relating to intracranial hemorrhage and antiplatelet agents. The reference sections of recent articles, guidelines and reviews were reviewed and pertinent articles identified. Studies were classified by …

Immune Recognition Of Self Nucleic Acids Driven By Endogenous Antimicrobial Peptides: Role In Autoimmunity, Dipyaman Ganguly

Dissertations and Theses (Open Access)

Innate immune recognition of extracellular host-derived self-DNA and self-RNA is prevented by endosomal seclusion of the Toll-like receptors (TLRs) in the dendritic cells (DCs). However, in psoriasis plasmacytoid dendritic cells have been found to be able to sense self-DNA molecules in complex with the endogenous cationic antimicrobial peptide LL37, which are internalized into the endosomal compartments and thus can access TLR9. We investigated whether this endogenous peptide can also interact with extracellular self-RNA and lead to DC activation. We found that LL37 binds self-RNA as well as self-DNA going into an electrostatic interaction; forms micro-aggregates of nano-scale particles protected from …

An Implantable Mosfet Dosimeter Modified To Act As A Fiducial Marker, Joseph S. Dick

Dissertations and Theses (Open Access)

In external beam radiation therapy, it is imperative that the prescribed dose is administered to the correct location and in the correct amount. Though several ex vivo methods of quality assurance are currently employed to achieve this goal, verifying that the correct dose is received within the patient in situ is impossible without the capability of measuring dose inside the patient. Recently, a method of measuring dose delivered within the patient has been developed, an implantable MOSFET dosimeter. This dosimeter is implanted within the patient and records the dose received. Since the dosimeter is implanted in the patient, it could …

Effect Of Acute Administration Of Angiopoietin-1 In Experimental Traumatic Spinal Cord Injury: Magnetic Resonance Imaging And Neurobehavioral Studies, Chirag B. Patel

Dissertations and Theses (Open Access)

Spinal cord injury (SCI) is a devastating condition that affects people in the prime of their lives. A myriad of vascular events occur after SCI, each of which contributes to the evolving pathology. The primary trauma causes mechanical damage to blood vessels, resulting in hemorrhage. The blood-spinal cord barrier (BSCB), a neurovascular unit that limits passage of most agents from systemic circulation to the central nervous system, breaks down, resulting in inflammation, scar formation, and other sequelae. Protracted BSCB disruption may exacerbate cellular injury and hinder neurobehavioral recovery in SCI.

In these studies, angiopoietin-1 (Ang1), an agent known to reduce …

Volumetric Modulated Arc Therapy Evaluation With The Radiological Physics Center Head And Neck Phantom, Kelly Kisling

Dissertations and Theses (Open Access)

Validation of treatment plan quality and dose calculation accuracy is essential for new radiotherapy techniques, including volumetric modulated arc therapy (VMAT). VMAT delivers intensity modulated radiotherapy treatments while simultaneously rotating the gantry, adding an additional level of complexity to both the dose calculation and delivery of VMAT treatments compared to static gantry IMRT. The purpose of this project was to compare two VMAT systems, Elekta VMAT and Varian RapidArc, to the current standard of care, IMRT, in terms of both treatment plan quality and dosimetric delivery accuracy using the Radiological Physics Center (RPC) head and neck (H&N) phantom. Clinically relevant …

Identification Of The Causative Bacteria In Musculoskeletal Infections Using 16s Rdna - Denaturing Gradient Gel Electrophoresis Analysis, Karen Gomez

Dissertations and Theses (Open Access)

Musculoskeletal infections are infections of the bone and surrounding tissues. They are currently diagnosed based on culture analysis, which is the gold standard for pathogen identification. However, these clinical laboratory methods are frequently inadequate for the identification of the causative agents, because a large percentage (25-50%) of confirmed musculoskeletal infections are false negatives in which no pathogen is identified in culture. My data supports these results. The goal of this project was to use PCR amplification of a portion of the 16S rRNA gene to test an alternative approach for the identification of these pathogens and to assess the diversity …

Transcriptional Suppression Of Mir-29b-1/Mir-29a Promoter By C-Myc, Hedgehog, And Nf-Kappab., Justin L. Mott, Satoshi Kurita, Sophie C. Cazanave, Steven F. Bronk, Nathan W. Werneburg, Martin E. Fernandez-Zapico

Journal Articles: Biochemistry & Molecular Biology

MicroRNAs regulate pathways contributing to oncogenesis, and thus the mechanisms causing dysregulation of microRNA expression in cancer are of significant interest. Mature mir-29b levels are decreased in malignant cells, and this alteration promotes the malignant phenotype, including apoptosis resistance. However, the mechanism responsible for mir-29b suppression is unknown. Here, we examined mir-29 expression from chromosome 7q32 using cholangiocarcinoma cells as a model for mir-29b downregulation. Using 5' rapid amplification of cDNA ends, the transcriptional start site was identified for this microRNA locus. Computational analysis revealed the presence of two putative E-box (Myc-binding) sites, a Gli-binding site, and four NF-kappaB-binding sites …

The Impact Of Adolescent Nicotine Exposure On Drug Dependence In Adulthood, Mai Alajaji

Theses and Dissertations

Nicotine is one of the first and most commonly abused drugs in adolescence. According to The Center for Disease Control, every day more than 6000 adolescents try their first cigarette and over 3000 of them become daily smokers. Smoking among adolescents is a strong predictor of future drug abuse and dependence in adulthood. A number of studies has suggests that adolescents pre-exposed to nicotine may suffer permanent disruption of the brain’s reward systems through changes in dopamine receptor function. We hypothesize that nicotine exposure during adolescence causes long lasting neurobiological alterations that increase the likelihood of cocaine use in adulthood. …

Multiple Mechanisms Of Consciousness: The Neural Correlates Of Emotional Awareness., Jayna M Amting, Steven G Greening, Derek G V Mitchell

Brain and Mind Institute Researchers' Publications

Emotional stimuli, including facial expressions, are thought to gain rapid and privileged access to processing resources in the brain. Despite this access, we are conscious of only a fraction of the myriad of emotion-related cues we face everyday. It remains unclear, therefore, what the relationship is between activity in neural regions associated with emotional representation and the phenomenological experience of emotional awareness. We used functional magnetic resonance imaging and binocular rivalry to delineate the neural correlates of awareness of conflicting emotional expressions in humans. Behaviorally, fearful faces were significantly more likely to be perceived than disgusted or neutral faces. Functionally, …

When Is Door-To-Balloon Time Critical? Analysis From The Horizons-Ami (Harmonizing Outcomes With Revascularization And Stents In Acute Myocardial Infarction) And Cadillac (Controlled Abciximab And Device Investigation To Lower Late Angioplasty Complications) Trials, Bruce R. Brodie Md, Bernard J. Gersh Mb, Chb, Dphil, Thomas D. Stuckey Md, Bernhard Witzenbichler Md, Giulio Guagliumi Md, Jan Z. Peruga Md, Dariusz Dudek Md, Cindy L. Grines Md, David A. Cox Md, Helen Parise Scd, Abhiram Prasad Md, Alexandra J. Lansky Md, Roxana Mehran Md, Gregg W. Stone Md

Department of Medicine

No abstract provided.

Warfarin Genotyping Using Three Different Platforms, Joel A. Lefferts, Mary C. Schwab, Uday B. Dandamudi, Hong-Kee Lee, Lionel D. Lewis, Gregory J. Tsongalis

Dartmouth Scholarship

Genetic testing for common variants in the CYP2C9 and VKORC1 genes may provide useful clinical information to guide dosing patients receiving oral warfarin. Specifically, the CYP2C9*2, CYP2C9*3 and either the VKORC1-1639 G>A or VKORC1 1173C>T polymorphisms can be used to help predict an approximate warfarin maintenance dose needed for a particular patient. Although clinical uptake and use of this genotyping has been slow, an increasing body of literature provides evidence of the clinical utility of supplementing traditional warfarin dosing algorithms with a pharmacogenetic approach. The availability of multiple methods for clinical genotyping provides the opportunity …

Deltanp63 Transcriptionally Regulates Atm To Control P53 Serine-15 Phosphorylation., Ashley L. Craig, Jitka Holcakova, Lee E. Finlan, Marta Nekulova, Roman Hrstka, Nuri Gueven, James Direnzo, Graeme Smith, Ted R. Hupp, Borivoj Vojtesek

Dartmouth Scholarship

Background: ΔNp63α is an epithelial progenitor cell marker that maintains epidermal stem cell self-renewal capacity. Previous studies revealed that UV-dam age induced p53 phosphorylation is confined to ΔNp63α-positive cells in the basal layer of human epithelium. Results: We now report that phosphorylatio n of the p53 tumour suppressor is po sitively regulated by ΔNp63α in immortalised human keratinocytes. ΔNp63α depletion by RNAi reduces steady-state ATM mRNA and protein levels, and attenuates p53 Serine-15 phosphorylation. Conversely, ectopic expression of ΔNp63α in p63-null tumour cells stimulates ATM transcription and p53 Seri ne-15 phosphorylation. We show that AT M is a …

The Mechanism Of Obesity In Rai1+/- Mice, Kristie Schmidt

Theses and Dissertations

Smith-Magenis syndrome (SMS) is a genetic disorder caused by a deletion or mutation of the retinoic acid induced 1 (RAI1) gene on chromosome 17p11.2 that results in haploinsufficiency. SMS patients with a deletion account for 90% of the cases, while the other 10% have a mutation in RAI1. The syndrome is characterized by cognitive impairment, craniofacial abnormalities, sleep disturbances, developmental delay, obesity, and behavioral phenotypes. SMS is thought to affect 1:25,000 live births, although due to similar infantile phenotypes with Down syndrome and Prader-Willi syndrome, SMS may be mis- or under-diagnosed. In a study of 54 children, it was shown …

Cell Death And Sustained Senescence Arrest In Colon Carcinoma And Melanoma Tumor Cells In Response To The Novel Microtubule Poison, Jg-03-14, Jonathan Biggers

Theses and Dissertations

Previous studies from this and other laboratories have shown that the novel microtubule poison, JG-03-14, which binds to the colchicine binding site of tubulin, has the capacity to promote both autophagy and apoptosis in breast tumor cells, as well as interfering with endothelial cell function and potentially disrupting tumor vasculature. The current work was designed to investigate the interaction between JG-03-14 and cell culture models of colon carcinoma and melanoma, specifically HCT116 human colon carcinoma cells and B16F10 murine melanoma cells. In both cases, JG-03-14 promoted death in the bulk of the treated population. FACS analysis, DAPI and TUNEL staining …

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 …

Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Enzymes that use distinct active site structures to perform identical reactions are known as analogous enzymes. The isolation of analogous enzymes suggests the existence of multiple enzyme structural pathways that can catalyze the same chemical reaction. A fundamental question concerning analogous enzymes is whether their distinct active-site structures would confer the same or different kinetic constraints to the chemical reaction, particularly with respect to the control of enzyme turnover. Here, we address this question with the analogous enzymes of bacterial TrmD and its eukaryotic and archaeal counterpart Trm5. TrmD and Trm5 catalyze methyl transfer to synthesize the m1G37 base at …

Teratology Primer-2nd Edition (7/9/2010), Sura Alwan, Steven B. Bleyl, Robert L. Brent, Christina D. Chambers, George P. Daston, Elaine M. Faustman, Richard H. Finnell, F. Clarke Fraser, Jan M. Freidman, Adriane Fugh-Berman, John M. Graham, Jr., Barbara F. Hales, Deborah K. Hansen, Lewis B. Holmes, Ronald D. Hood, Robert J. Kavlock, Thomas B. Knudsen, Joseph Lary, Donald R. Mattison, Richard K. Miller, James L. Mills, Janine E. Polifka, Sonja A. Rasmussen, Bernard Robaire, John M. Rogers, Gary C. Schoenwolf, Anthony R. Scialli, Gary M. Shaw, Amar V. Singh, William Slikker, Jr., Ann P. Streissguth, Melissa S. Tassinari, Janet Uriu-Adams, Charles V. Vorhees, Elora J. Weringer

Department of Pediatrics Faculty Papers

Foreword:

What is Teratology?

“What a piece of work is an embryo!” as Hamlet might have said. “In form and moving how express and admirable! In complexity how infinite!” It starts as a single cell, which by repeated divisions gives rise to many genetically identical cells. These cells receive signals from their surroundings and from one another as to where they are in this ball of cells —front or back, right or left, headwards or tailwards, and what they are destined to become. Each cell commits itself to being one of many types; the cells migrate, combine into tissues, or …

Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Enzymes that use distinct active site structures to perform identical reactions are known as analogous enzymes. The isolation of analogous enzymes suggests the existence of multiple enzyme structural pathways that can catalyze the same chemical reaction. A fundamental question concerning analogous enzymes is whether their distinct active-site structures would confer the same or different kinetic constraints to the chemical reaction, particularly with respect to the control of enzyme turnover. Here, we address this question with the analogous enzymes of bacterial TrmD and its eukaryotic and archaeal counterpart Trm5. TrmD and Trm5 catalyze methyl transfer to synthesize the m1G37 base at …

Pcif1 Modulates Pdx1 Protein Stability And Pancreatic Β Cell Function And Survival In Mice, Kathryn C. Claiborn, Mira M. Sachdeva, Corey E. Cannon, David N. Groff, Jeffrey D. Singer, Doris A. Stoffers

Biology Faculty Publications and Presentations

The homeodomain transcription factor pancreatic duodenal homeobox 1 (Pdx1) is a major mediator of insulin transcription and a key regulator of the β cell phenotype. Heterozygous mutations in PDX1 are associated with the development of diabetes in humans. Understanding how Pdx1 expression levels are controlled is therefore of intense interest in the study and treatment of diabetes. Pdx1 C terminus–interacting factor-1 (Pcif1, also known as SPOP) is a nuclear protein that inhibits Pdx1 transactivation. Here, we show that Pcif1 targets Pdx1 for ubiquitination and proteasomal degradation. Silencing of Pcif1 increased Pdx1 protein levels in cultured mouse β cells, and Pcif1 …

Avirulent Uracil Auxotrophs Based On Disruption Of Orotidine-5′-Monophosphate Decarboxylase Elicit Protective Immunity To Toxoplasma Gondii, Barbara A. Fox, David J. Bzik

Dartmouth Scholarship

The orotidine-5'-monophosphate decarboxylase (OMPDC) gene, encoding the final enzyme of the de novo pyrimidine biosynthesis pathway, was deleted using Toxoplasma gondii KU80 knockouts to develop an avirulent nonreverting pyrimidine auxotroph strain. Additionally, to functionally address the role of the pyrimidine salvage pathway, the uridine phosphorylase (UP) salvage activity was knocked out and a double knockout of UP and OMPDC was also constructed. The nonreverting DeltaOMPDC, DeltaUP, and DeltaOMPDC DeltaUP knockout strains were evaluated for pyrimidine auxotrophy, for attenuation of virulence, and for their ability to elicit potent immunity to reinfection. The DeltaUP knockout strain was replication competent and virulent. In …

Neural Plasticity And Treatment-Induced Recovery Of Sentence Processing In Agrammatism, Cynthia K. Thompson, Dirk B. Den Ouden, Borna Bonakdarpour, Kyla Garibaldi, Todd B. Parrish

Communication Sciences and Disorders Faculty Articles and Research

This study examined patterns of neural activation associated with treatment-induced improvement of complex sentence production (and comprehension) in six individuals with stroke-induced agrammatic aphasia, taking into account possible alterations in blood flow often associated with stroke, including delayed time-to-peak of the hemodynamic response function (HRF) and hypoperfused tissue. Aphasic participants performed an auditory verification fMRI task, processing object cleft, subject cleft, and simple active sentences, prior to and following a course of Treatment of Underlying Forms (TUF; Thompson et al., 2003), a linguistically based approach for treating aphasic sentence deficits, which targeted object relative clause constructions. The patients also were …

Fenotipo Y Genotipo Del Virus De La Diarrea Viral Aislado De Bovinos En El Perú., Mariluz Araínga, Hermelinda Rivera G., Juan Carlos Huaman G., Alberto Manchego S.

Journal Articles: Pharmacology & Experimental Neuroscience

The aim of this study was to determine the phenotype and genotype of Bovine Viral Diarrhoea Virus (BVDV) in Peruvian cattle. During the period 1998-2007, tissues of aborted fetus, blood, serum or plasma samples of bovine with acute infection or persistently infected from dairy herds of various locations in the country were collected and the BVDV antigen was detected by immnunofluorescence or capture ELISA tests, and positive samples were inoculated en BVDV free BT cells and cultured until third passage to determine the biotype. Both animal tissues and third passage of positive samples were tested by a Real Time Reverse …

Prolongation Of Carrageenan-Induced Inflammation In Human Colonic Epithelial Cells By Activation Of An Nfκb-Bcl10 Loop, Alip Borthakur, Sumit Bhattacharyya, Arivarasu N. Anbazhagan, Anoop Kumar, Pradeep K. Dudeja, Joanne K. Tobacman

Clinical & Translational Sciences

Carrageenan, a sulfated polysaccharide that is widely used as a food additive, induces inflammatory responses in animal models and human cells. The carrageenan-induced inflammatory cascades involve tolllike receptor (TLR)4- and B-cell leukemia/lymphoma (BCL)10-dependent activation of NF-κB, leading to increased IL-8 production. Translocations involving BCL10 in the mucosa-associated lymphoid tissue (MALT) lymphomas are associated with constitutive activation of NF-κB. This report presents a mechanism by which carrageenan exposure leads to prolonged activation of both BCL10 and NF-κB in human colonic epithelial cells. Study findings demonstrate that nuclear RelA and RelB bind to an NF-κB binding motif in the BCL10 promoter in …

Chronic Obstructive Pulmonary Disease: Longitudinal Hyperpolarized (3)He Mr Imaging, Miranda Kirby, Lindsay Mathew, Andrew Wheatley, Giles E Santyr, David G Mccormack, Grace Parraga

Medical Biophysics Publications

PURPOSE: To quantitatively evaluate a small pilot group of ex-smokers with chronic obstructive pulmonary disease (COPD) and healthy volunteers during approximately 2 years by using hyperpolarized helium 3 ((3)He) magnetic resonance (MR) imaging.

MATERIALS AND METHODS: All subjects provided written informed consent to the study protocol, which was approved by the local research ethics board and Health Canada and was compliant with the Personal Information Protection and Electronic Documents Act and HIPAA. Hyperpolarized (3)He MR imaging, hydrogen 1 MR imaging, spirometry, and plethysmography were performed in 15 ex-smokers with COPD and five healthy volunteers (with the same mean age and …

Deficits In Attention To Emotional Stimuli Distinguish Youth With Severe Mood Dysregulation From Youth With Bipolar Disorder., Brendan A Rich, Melissa A Brotman, Daniel P Dickstein, Derek G V Mitchell, R James R Blair, Ellen Leibenluft

Brain and Mind Institute Researchers' Publications

Studying attention in the context of emotional stimuli may aid in differentiating pediatric bipolar disorder (BD) from severe mood dysregulation (SMD). SMD is characterized by chronic irritability, arousal, and hyper-reactivity; SMD youth frequently receive a BD diagnosis although they do not meet DSM-IV criteria for BD because they lack manic episodes. We compared 57 BD (14.4 +/- 2.9 years old, 56% male), 41 SMD (12.6 +/- 2.6 years old, 66% male), and 33 control subjects (13.7 +/- 2.5 years old, 52% male) using the Emotional Interrupt task, which examines how attention is impacted by positive, negative, or neutral distracters. We …

Antispasmodic, Bronchodilator And Blood Pressure Lowering Properties Of Hypericum Oblongifolium - Possible Mechanism Of Action, Arif-Ullah Khan, Munasib Khan, Fazal Subhan, Anwar Gilani

Department of Biological & Biomedical Sciences

The crude extract of Hypericum oblongifolium (Ho.Cr), which tested positive for flavonoids, saponins and tannins caused concentration-dependent (0.1-1.0 mg/mL) relaxation of spontaneous and high K(+) (80 mM)-induced contractions in isolated rabbit jejunum preparations, suggesting a Ca(++) antagonistic effect, which was confirmed when pretreatment of the tissue with Ho.Cr produced a rightward shift in the Ca(++) concentration-response curves, like that caused by verapamil. Ho.Cr relaxed carbachol (1 mu M) and high K(+)-induced contractions in guinea pig tracheal preparations. It caused a dose-dependent (3-100 mg/kg) fall in arterial blood pressure of rats under anesthesia. In isolated guinea pig atria, Ho.Cr caused inhibition …