Medicine and Health Sciences Commons^™

Stromal Caveolin-1 Levels Predict Early Ductal Carcinoma In Situ Progression To Invasive Breast Carcinoma, A. K. Witkiewicz, A. Dasgupta, G. F. Schwartz, Kh H. Nguyen, H. R. Rui, M. P. Lisanti

Department of Cancer Biology Faculty Papers

With the increased use of screening mammography, the incidence of ductal carcinoma in situ (DCIS) has increased substantially and it currently accounts for 20-30% of newly diagnosed breast carcinomas in United States. Breast conserving therapy with or without radiotherapy is the accepted treatment for most cases of DCIS. However, the local recurrence rate with such therapy rages from 10 to 40% with half of these patients developing invasive carcinoma. Tamoxifen, used as an adjuvant systemic therapy for DCIS, does not increase overall survival and data on reduction of local recurrence rates are conflicting.

The current classification for DCIS based on …

Computational Prediction Of The Agregated Structure Of Denatured Lysozyme, Pongsathorn Chotikasemsri

Masters Theses & Specialist Projects

Mis-folded proteins and their associated aggregates are a contributing factor in some human diseases. In this study we used the protein lysozyme as a model to define aggregation structures under denaturing conditions. Sasahara et al. (2007), Frare et al. (2009, 2006), and Rubin et al. (2008) observed conditions where heat denatured lysozyme formed fibril structures that were observed to be 8-17 nanometers in diameter under the electron microscope. Even though the crystal structure of lysozyme is known, the denatured form of this protein is still unknown. Therefore, we used Rosetta++ protein folding and blind docking software to create in silico …

Trnas: Cellular Barcodes For Amino Acids, Ranat Banerjee, Shawn Chen, Kiley Dare, Marla Gilreath, Mette Praetorius-Ibba, Medha Raina, Noah M. Reynolds, Theresa E. Rogers, Hervé Roy, Srujana S. Yadavalli, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The role of tRNA in translating the genetic code has received considerable attention over the last 50 years, and we now know in great detail how particular amino acids are specifically selected and brought to the ribosome in response to the corresponding mRNA codon. Over the same period, it has also become increasingly clear that the ribosome is not the only destination to which tRNAs deliver amino acids, with processes ranging from lipid modification to antibiotic biosynthesis all using aminoacyl‐tRNAs as substrates. Here we review examples of alternative functions for tRNA beyond translation, which together suggest that the role of …

Ppar Agonists Down-Regulate The Expression Of Atp10c Mrna During Adipogenesis, A Peretich, Maria Cekanova Ms, Rndr, Phd, S Hurst, Sj Baek, Madhu Dahr

Faculty Publications and Other Works -- Biochemistry, Cellular and Molecular Biology

No abstract provided.

Peer-Led, School-Based Nutrition Education For Young Adolescents: Feasibility And Process Evaluation Of The Teens Study, Mary Story, Leslie A. Lytle, Amanda Birnbaum, Cheryl L. Perry

Department of Public Health Scholarship and Creative Works

Peer education has become a popular strategy for health promotion interventions with adolescents, but it has not been used widely in school‐based nutrition education. This paper describes and reports on the feasibility of the peer leader component of school‐based nutrition intervention for young adolescents designed to increase fruit and vegetable intakes and lower-fat foods. About 1,000 seventh‐grade students in eight schools received the nutrition intervention. Of these, 272 were trained as peer leaders to assist the teacher in implementing the activities. Results from a multicomponent process evaluation based on peer leader and classroom student feedback, direct classroom observation, and teacher …

The Production Of Antibody By Invading B Cells Is Required For The Clearance Of Rabies Virus From The Central Nervous System., D Craig Hooper, Timothy W Phares, Marzena J Fabis, Anirban Roy

Department of Cancer Biology Faculty Papers

BACKGROUND: The pathogenesis of rabies is associated with the inability to deliver immune effectors across the blood-brain barrier and to clear virulent rabies virus from CNS tissues. However, the mechanisms that facilitate immune effector entry into CNS tissues are induced by infection with attenuated rabies virus.

METHODOLOGY/PRINCIPAL FINDINGS: Infection of normal mice with attenuated rabies virus but not immunization with killed virus can promote the clearance of pathogenic rabies virus from the CNS. T cell activity in B cell-deficient mice can control the replication of attenuated virus in the CNS, but viral mRNA persists. Low levels of passively administered rabies …

Proteomic And Phospho-Proteomic Profile Of Human Platelets In Basal, Resting State: Insights Into Integrin Signaling, Amir H. Qureshi, Vineet Chaoji, Dony Maiguel, Mohd Hafeez Faridi, Constantinos J. Barth, Saeed M. Salem, Mudita Singhal, Darren Stoub, Bryan Krastins, Mitsunori Ogihara, Mohammed J. Zaki, Vineet Gupta

Faculty Work Comprehensive List

During atherogenesis and vascular inflammation quiescent platelets are activated to increase the surface expression and ligand affinity of the integrin αIIbβ3 via inside-out signaling. Diverse signals such as thrombin, ADP and epinephrine transduce signals through their respective GPCRs to activate protein kinases that ultimately lead to the phosphorylation of the cytoplasmic tail of the integrin αIIbβ3 and augment its function. The signaling pathways that transmit signals from the GPCR to the cytosolic domain of the integrin are not well defined. In an effort to better understand these pathways, we employed a combination of proteomic profiling and computational analyses of isolated …

Baseline Predictors Of Virological Response For Chronic Hepatitis B Patients, Xue-Jie Wu, Yan Wang, Ji Chen, Gui-Qiang Wang

Pharmacology and Toxicology Faculty Publications

AIM: To determine which baseline factors of chronic hepatitis B patients are predictive of virological response to Peginterferon α-2b therapy. METHODS: A total of 21 HBeAg-positive chronic hepatitis B (CHB) patients treated with Peginterferon α-2b were recruited. They were treated with Peginterferon α-2b (0.5-1.0 µg/kg per week) for 24 wk and followed up for 24 wk. Clinical and laboratory data of the patients were determined at pretreatment and at week 12, at 24 during treatment, and at week 48 during follow up. RESULTS: Ten patients achieved a virological response at the end of treatment. Their baseline serum alanine aminotransferase (ALT), …

Broad Range Amino Acid Specificity Of Rna-Dependent Lipid Remodelling By Multiple Peptide Resistance Factors, Hervé Roy, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacylphosphatidylglycerol synthases (aaPGSs) are multiple peptide resistance factors that transfer amino acids from aminoacyl-tRNAs to phosphatidylglycerol (PG) in the cytoplasmic membrane. Aminoacylation of PG is used by bacteria to decrease the net negative charge of the cell envelope, diminishing affinity for charged molecules and allowing for adaptation to environmental changes. Lys-PGS, which transfers lysine to PG, is essential for the virulence of certain pathogens, providing resistance to both host cationic antimicrobial peptides and therapeutic antibiotics. Ala-PGS was also recently described, but little is known about the possible activities of other members of the highly diverse aaPGS family of proteins. Systematic …

The Cca Anticodon Specifies Separate Functions Inside And Outside Translation In Bacillus Cereus, Sandro F. Ataide, Theresa E. Rogers, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacillus cereus 14579 encodes two tRNAs with the CCA anticodon, tRNA^Trp and tRNA^Other. tRNA^Trp was separately aminoacylated by two enzymes, TrpRS1 and TrpRS2, which share only 34% similarity and display different catalytic capacities and specificities. TrpRS1 was 18-fold more proficient at aminoacylating tRNA^Trp with Trp, while TrpRS2 more efficiently utilizes the Trp analog 5-hydroxy Trp. tRNA^Other was not aminoacylated by either TrpRS but instead by the combined activity of LysRS1 and LysRS2, which recognized sequence elements absent from tRNA^Trp. Polysomes were found to contain tRNA^Trp, consistent with its role in …

Spiroadamantyl 1,2,4-Trioxolane, 1,2,4-Trioxane, And 1,2,4-Trioxepane Pairs: Relationship Between Peroxide Bond Iron(Ii) Reactivity, Heme Alkylation Efficiency, And Antimalarial Activity, Xiaofang Wang, Darren J. Creek, Yuxiang Dong, Jacques Chollet, Christian Scheurer, Sergio Wittlin, Susan A. Charman, Patrick H. Dussault, James K. Wood, Jonathan L. Vennerstrom

Chemistry Faculty Publications

These data suggest that iron(II) reactivity for a set of homologous spiroadamantyl 1,2,4-trioxolane, 1,2,4-trioxane, and 1,2,4-trioxepane peroxide heterocycles is a necessary, but insufficient, property of animalarial peroxides. Heme alkylation efficiency appears to give a more accurate prediction of antimalarial activity than FeSO4-mediated reaction rates, suggesting that antimalarial activity is not merely dependent on peroxide bond cleavage, but also on the ability of reactive intermediates to alkylate heme or other proximal targets.

Coupling Between The Voltage-Sensing And Phosphatase Domains Of Ci-Vsp, Carlos A. Villalba-Galea, Francesco Miceli, Maurizio Taglialatela, Francisco Bezanilla

School of Pharmacy Faculty Articles

The Ciona intestinalis voltage sensor-containing phosphatase (Ci-VSP) shares high homology with the phosphatidylinositol phosphatase enzyme known as PTEN (phosphatase and tensin homologue deleted on chromosome 10). We have taken advantage of the similarity between these proteins to inquire about the coupling between the voltage sensing and the phosphatase domains in Ci-VSP. Recently, it was shown that four basic residues (R11, K13, R14, and R15) in PTEN are critical for its binding onto the membrane, required for its catalytic activity. Ci-VSP has three of the basic residues of PTEN. Here, we show that when R253 and R254 (which are the homologues …

Detecting, Preventing, And Treating Sexually Transmitted Diseases Among Adolescent Arrestees: An Unmet Public Health Need, Christopher Salvatore, Steven Belenko, Richard Dembo, Matthew Rollie, Kristina Childs

Department of Justice Studies Faculty Scholarship and Creative Works

Studies of detained and incarcerated adolescent offenders in the United States indicate that these juveniles have an elevated risk of sexually transmitted diseases (STDs). However, many more arrestees enter the “front end” of the juvenile justice system that is detained or incarcerated, and research into the STD risk profiles and service needs of this larger group is lacking. An expansion of STD testing (including of asymptomatic youths), prevention, and treatment is needed, as is improved knowledge about gender- and race-specific services. A pilot program in Florida has shown that juvenile justice and public health systems can collaborate to implement STD …

Plant Vaccines: An Immunological Perspective., Douglas C. Hooper

Department of Cancer Biology Faculty Papers

The advent of technologies to express heterologous proteins in planta has led to the proposition that plants may be engineered to be safe, inexpensive vehicles for the production of vaccines and possibly even vectors for their delivery. The immunogenicity of a variety of antigens of relevance to vaccination expressed in different plants has been assessed. The purpose of this article is to examine the utility of plant-expression systems in vaccine development from an immunological perspective.

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 …

Resampling And Editing Of Mischarged Trna Prior To Translation Elongation, Jiqiang Ling, Byung Ran So, Srujana S. Yadavalli, Hervé Roy, Shinichiro Shoji, Kurt Fredrick, Karin Musier-Forsyth, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Faithful translation of the genetic code depends on the GTPase EF-Tu delivering correctly charged aminoacyl-tRNAs to the ribosome for pairing with cognate codons. The accurate coupling of cognate amino acids and tRNAs by the aminoacyl-tRNA synthetases is achieved through a combination of substrate specificity and product editing. Once released by aminoacyl-tRNA synthetases, both cognate and near-cognate aminoacyl-tRNAs were considered to be committed to ribosomal protein synthesis through their association with EF-Tu. Here we show instead that aminoacyl-tRNAs in ternary complex with EF-Tu•GTP can readily dissociate and rebind to aminoacyl-tRNA synthetases. For mischarged species, this allows resampling by the product editing …

Multimeric Hemicellulases Facilitate Biomass Conversion, Zhanmin Fan, Kurt Wagschal, Wei Chen, Michael D. Montross, Charles C. Lee, Ling Yuan

Plant and Soil Sciences Faculty Publications

Two highly active trifunctional hemicellulases were constructed by linking the catalytic portion of a xylanase with an arabinofuranosidase and a xylosidase, using either flexible peptide linkers or linkers containing a cellulose-binding domain. The multifunctional enzymes retain the parental enzyme properties and exhibit synergistic effects in hydrolysis of natural xylans and corn stover.

Immunological Assessment Of Plant-Derived Avian Flu H5/Ha1 Variants., S Spitsin, V Andrianov, N Pogrebnyak, Y Smirnov, N Borisjuk, C Portocarrero, V Veguilla, H Koprowski, M Golovkin

Department of Cancer Biology Faculty Papers

Polypeptide variants of the HA1 antigenic domain of the H5N1 avian influenza virus hemagglutinin (HA) molecule were produced in plants using transient and stable expression systems and fused with His/c-myc tags or with mouse or human Fc antibody fragments. The resulting peptides were purified and used for intramuscular immunization of mice. While the recombinant HA1 variants induced a significant serum humoral immune response in the mice, none of the HA1 preparations induced virus-neutralizing antibodies. Fusion with the Fc fragment improved overall yield of the constructs and allowed purification requiring only a single step, but led to no detectable fusion-related enhancement …

New Dosing Schedules Of Dasatinib For Cml And Adverse Event Management, Siu Fun Wong

Pharmacy Faculty Articles and Research

Resistance to imatinib in patients with chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) has emerged as a significant clinical issue. Dasatinib is a tyrosine kinase inhibitor that has 325-fold greater in vitro activity against native BCR-ABL (breakpoint cluster region-Abelson leukemia virus) compared with imatinib and can overcome primary (intrinsic) and secondary (acquired) imatinib resistance. Here, we review the clinical profile of dasatinib in imatinib-resistant and -intolerant patients and share clinical approaches for managing adverse events (AEs) to ensure maximum patient benefit. References were obtained through literature searches on PubMed as well as from the Proceedings …

Atorvastatin May Have No Effect On Acute Phase Reaction In Children After Intravenous Bisphosphonate Infusion., Tarak Srivastava, Connie J. Haney, Uri S. Alon

Manuscripts, Articles, Book Chapters and Other Papers

Intravenous bisphosphonate therapy is associated with acute phase reaction characterized by fever and musculoskeletal pain. Bisphosphonates have been shown in vitro to activate gammadeltaT-cells to proliferate and produce cytokines, suggesting a role in acute phase reaction, which can be effectively blocked by statins. We conducted a double-blind randomized crossover placebo controlled study in 12 children (12.1 +/- 4.2 yr; 10 girls and 2 boys) receiving intravenous bisphosphonates to evaluate whether statins can be used to prevent acute phase reaction associated with therapy. Children received two cycles given 3-4 mo apart of intravenous bisphosphonate given on 2 consecutive days in each …

Adaptation Of The Bacterial Membrane To Changing Environments Using Aminoacylated Phospholipids, Hervé Roy, Kiley Dare, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Fine‐tuning of the biophysical properties of biological membranes is essential for adaptation of cells to changing environments. For instance, to lower the negative charge of the lipid bilayer, certain bacteria add lysine to phosphatidylglycerol (PG) converting the net negative charge of PG (−1) to a net positive charge in Lys‐PG (+1). Reducing the net negative charge of the bacterial cell wall is a common strategy used by bacteria to resist cationic antimicrobial peptides (CAMPs) secreted by other microbes or produced by the innate immune system of a host organism. The article by Klein et al. in the current issue of …

High Adsorption Rate Is Detrimental To Bacteriophage Fitness In A Biofilm-Like Environment., Romain Gallet, Yongping Shao, Ing-Nang Wang

Department of Cancer Biology Faculty Papers

BACKGROUND: Bacterial biofilm is ubiquitous in nature. However, it is not clear how this crowded habitat would impact the evolution of bacteriophage (phage) life history traits. In this study, we constructed isogenic lambda phage strains that only differed in their adsorption rates, because of the presence/absence of extra side tail fibers or improved tail fiber J, and maker states. The high cell density and viscosity of the biofilm environment was approximated by the standard double-layer agar plate. The phage infection cycle in the biofilm environment was decomposed into three stages: settlement on to the biofilm surface, production of phage progeny …

Stat5 Regulation Of Bcl10 Parallels Constitutive Nfkappab Activation In Lymphoid Tumor Cells., Zsuzsanna S Nagy, Matthew J Lebaron, Jeremy A Ross, Abhisek Mitra, Hallgeir Rui, Robert A Kirken

Department of Cancer Biology Faculty Papers

BACKGROUND: Signal Transducer and Activator of Transcription 5 A and B (STAT5) are key survival factors in cells of the lymphoid lineage. Identification of novel, tissue-specific STAT5 regulated genes would advance the ability to combat diseases due to aberrant STAT5 signaling. In the present work a library of human STAT5 bound genomic elements was created and validated. RESULTS: Of several STAT5 responsive genomic regulatory elements identified, one was located within the first intron of the human BCL10 gene. Chromatin immuno-precipitation reactions confirmed constitutive in vivo STAT5 binding to this intronic fragment in various human lymphoid tumor cell lines. Interestingly, non-phosphorylated …

Antitumour And Antimalarial Activity Of Artemisinin–Acridine Hybrids, Michael Jones, Amy Mercer, Paul Stocks, Louise La Pensee, Rick Cosstick, B. Kevin Park, Miriam Kennedy, Ivo Piantanida, Stephen Ward, Jill Davies, Patrick Bray, Sarah Rawe, Jonathon Baird, Tafadzwa Charidza, Omar Janneh, Paul O'Neill

Articles

Artemisinin–acridine hybrids were prepared and evaluated for their in vitro activity against tumour cell lines and a chloroquine sensitive strain of Plasmodium falciparum. They showed a 2–4-fold increase in activity against HL60, MDA-MB-231 and MCF-7 cells in comparison with dihydroartemisinin (DHA) and moderate antimalarial activity. Strong evidence that the compounds induce apoptosis in HL60 cells was obtained by flow cytometry, which indicated accumulation of cells in the G1 phase of the cell cycle.

Understanding The Physical Properties That Control Protein Crystallization By Analysis Of Largescale Experimental Data, W. Nicholson Price Ii, Yang Chen, Samuel K. Handelman, Helen Neely, Philip Manor, Richard Karlin, Rajesh Nair, Jinfeng Liu, Michael Baran, John Everett, Saichiu N. Tong, Farhad Forouhar, Swarup S. Swaminathan, Thomas Acton, Rong Xiao, Joseph R. Luft, Angela Lauricella, George T. Detitta, Burkhard Rost, Gaetano T. Montelione, John T. Hunt

Law Faculty Scholarship

Crystallization is the most serious bottleneck in high-throughput protein-structure determination by diffraction methods. We have used data mining of the large-scale experimental results of the Northeast Structural Genomics Consortium and experimental folding studies to characterize the biophysical properties that control protein crystallization. This analysis leads to the conclusion that crystallization propensity depends primarily on the prevalence of well-ordered surface epitopes capable of mediating interprotein interactions and is not strongly influenced by overall thermodynamic stability. We identify specific sequence features that correlate with crystallization propensity and that can be used to estimate the crystallization probability of a given construct. Analyses of …

Synthesis And Evaluation Of Phosphopeptides Containing Iminodiacetate Groups As Binding Ligands Of The Src Sh2 Domain, Guofeng Ye, Aaron D. Schuler, Yousef Ahmadibeni, Joel R. Morgan, Absar Faruqui, Kezhen Huang, Gongqin Sun, John A. Zebala, Keykavous Parang

Pharmacy Faculty Articles and Research

Phosphopeptide pTyr-Glu-Glu-Ile (pYEEI) has been introduced as an optimal Src SH2 domain ligand. Peptides, Ac-K(IDA)pYEEIEK(IDA) (1), Ac-KpYEEIEK (2), Ac-K(IDA)pYEEIEK (3), and Ac-KpYEEIEK(IDA) (4), containing 0–2 iminodiacetate (IDA) groups at the N- and C-terminal lysine residues were synthesized and evaluated as the Src SH2 domain binding ligands. Fluorescence polarization assays showed that peptide 1 had a higher binding affinity (Kd = 0.6 μM) to the Src SH2 domain when compared with Ac-pYEEI (Kd = 1.7 μM), an optimal Src SH2 domain ligand, and peptides 2–4 (Kd = 2.9–52.7 μM). The binding affinity of peptide 1 to the SH2 domain was reduced …

The C1 And C2 Domains Target Human Type 6 Adenylyl Cyclase To Lipid Rafts And Caveolae, Muthusamy Thangavel, Xiaoqiu Liu, Shu Qiang Sun, Joseph Kaminsky, Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Previous data has shown that adenylyl cyclase type 6 (AC6) is expressed principally in lipid rafts or caveolae of cardiac myocytes and other cell types while certain other isoforms of AC are excluded from these microdomains. The mechanism by which AC6 is localized to lipid rafts or caveolae is unknown. In this study, we show AC6 is localized in lipid rafts of COS-7 cells (expressing caveolin-1) and in HEK-293 cells or cardiac fibroblasts isolated from caveolin-1 knock-out mice (both of which lack prototypical caveolins). To determine the region of AC6 that confers raft localization, we independently expressed each of the …

Human Cytomegalovirus Us28: A Functionally Selective Chemokine Binding Receptor, Jennifer Totonchy, Jay A. Nelson, Daniel N. Streblow

Pharmacy Faculty Articles and Research

The Human Cytomegalovirus (HCMV)-encoded chemokine receptor US28 is the most well-characterized of the four chemokine receptor-like molecules found in the HCMV genome. US28 been studied as an important virulence factor for HCMV-mediated vascular disease and, more recently, in models of HCMV-associated malignancy. US28 is a rare multi-chemokine family binding receptor with the ability to bind ligands from two distinct chemokine classes. Ligand binding to US28 activates cell-type and ligand-specific signaling pathways leading to cellular migration, an example receptor functional selectivity. Additionally, US28 has been demonstrated to constitutively activate PLC and NFkB. Understanding the structure/function relationships between US28, its ligands and …

Isoniazid Completion Rates For Latent Tuberculosis Infection Among College Students Managed By A Community Pharmacist, Karl M. Hess, Jeffery A. Goad, Joanne Wu, Kathleen Johnson

Pharmacy Faculty Articles and Research

Objective: The authors' objective was to document 9-month and previously recommended 6-month treatment completion rates for latent tuberculosis infection (LTBI) in a pharmacist-managed LTBI clinic in a community pharmacy oil a college Campus. and to describe patient characteristics. Participants: Participants were university Students diagnosed with LTBI. Methods: The authors conducted a retrospective review, of pharmacy records from 2000 to 2006. Main outcome measures included 6-month and 9-month LTBI treatment completion rates, total isoniazid (INH) tablets taken. characteristics of completers versus noncompleters. average time to treatment completion, and reported adverse drug events. Results: The 9-month completion rate was 59%, and the …

The Guinea Pig Ileum Lacks The Direct, High-Potency, M2-Muscarinic, Contractile Mechanism Of The Mouse Ileum, Michael T. Griffin, Minoru Matsui, Rennolds S. Ostrom, Frederick J. Ehlert

Pharmacy Faculty Articles and Research

We explored whether the M2 muscarinic receptor in the guinea pig ileum elicits a highly potent, direct-contractile response, like that from the M3 muscarinic receptor knockout mouse. First, we characterized the irreversible receptor-blocking activity of 4-DAMP mustard in ileum from muscarinic receptor knockout mice to verify its M3 selectivity. Then, we used 4-DAMP mustard to inactivate M3 responses in the guinea pig ileum to attempt to reveal direct, M2 receptor-mediated contractions. The muscarinic agonist, oxotremorine-M, elicited potent contractions in ileum from wild-type, M2 receptor knockout, and M3 receptor knockout mice characterized by negative log EC50 (pEC50) values ± SEM of …