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Lin H, Anderson DT, Clemmons A, Eudy J, Nutt B, Stevens C, White S, Forehand C. Performance of Methicillin-Resistant Staphylococcus aureus Polymerase Chain Reaction Nasal Screening for Ruling Out MRSA Pneumonia in Hospitalized, Immunocompromised Patients. J Pharm Technol 2023; 39:191-194. [PMID: 37529151 PMCID: PMC10387814 DOI: 10.1177/87551225231182876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023] Open
Abstract
Background: Recent literature demonstrates support for using methicillin-resistant Staphylococcus aureus (MRSA) nasal swab polymerase chain reaction (NaPCR) screening as an antimicrobial stewardship tool aiding early de-escalation of anti-MRSA antimicrobials. However, immunocompromised patients have been underrepresented in previous studies despite increased risk of morbidity and mortality from multidrug-resistant organisms (MDRO). Objective: The purpose of this study was to determine the negative predictive value (NPV) of the MRSA NaPCR in hospitalized, immunocompromised adult patients with suspected pneumonia. Methods: A single-center, retrospective, observational review was conducted of hospitalized, immunocompromised adult patients that had an MRSA NaPCR obtained between March 1, 2020 and January 10, 2021. For inclusion, bacterial cultures must have been collected within 2 weeks after MRSA NaPCR. The primary outcome was the NPV of MRSA NaPCR in hospitalized, immunocompromised patients with suspected pneumonia. Secondary outcomes include NPV in other infections. Results: Between March 1, 2020 and January 10, 2021, 59 patients with 78 unique cultures, including 28 respiratory cultures, were included in the study. The NPV of the MRSA NaPCR for pneumonia was 91.7%. The NPV for bloodstream infections was 100% and for urinary tract infections was 100%, but interpretation of these results should be cautioned due to the small sample sizes. Conclusion: The NPV of MRSA NaPCR in pneumonia remains high in this study. The MRSA NaPCR has utility as a de-escalation tool in hospitalized, immunocompromised adult patients, but larger studies are warranted to evaluate all immunocompromised patient populations.
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Affiliation(s)
- Hui Lin
- Department of Pharmacy, Yale New Haven Hospital, New Haven, CT, USA
| | - Daniel T. Anderson
- Department of Pharmacy, Augusta University Medical Center, Augusta, GA, USA
| | - Amber Clemmons
- Department of Pharmacy, Augusta University Medical Center, Augusta, GA, USA
- Department of Clinical & Administrative Pharmacy, College of Pharmacy, University of Georgia, Augusta, GA, USA
| | - Joshua Eudy
- Department of Pharmacy, Augusta University Medical Center, Augusta, GA, USA
| | - Brittny Nutt
- Department of Clinical & Administrative Pharmacy, College of Pharmacy, University of Georgia, Augusta, GA, USA
| | - Caroline Stevens
- Department of Clinical & Administrative Pharmacy, College of Pharmacy, University of Georgia, Augusta, GA, USA
| | - Sydney White
- Department of Clinical & Administrative Pharmacy, College of Pharmacy, University of Georgia, Augusta, GA, USA
| | - Christy Forehand
- Department of Pharmacy, Augusta University Medical Center, Augusta, GA, USA
- Department of Clinical & Administrative Pharmacy, College of Pharmacy, University of Georgia, Augusta, GA, USA
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Clemmons A, Gandhi A, Clarke A, Jimenez S, Le T, Ajebo G. Premedications for Cancer Therapies: A Primer for the Hematology/Oncology Provider. J Adv Pract Oncol 2022; 12:810-832. [PMID: 35295545 PMCID: PMC8631343 DOI: 10.6004/jadpro.2021.12.8.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Chemotherapeutic agents and radiation therapy are associated with numerous potential adverse events (AEs). Many of these common AEs, namely chemotherapy- or radiation-induced nausea and vomiting, hypersensitivity reactions, and edema, can lead to deleterious outcomes (such as treatment nonadherence or cessation, or poor clinical outcomes) if not prevented appropriately. The occurrence and severity of these AEs can be prevented with the correct prescribing of prophylactic medications, often called "premedications." The advanced practitioner in hematology/oncology should have a good understanding of which chemotherapeutic agents are known to place patients at risk for these adverse events as well as be able to determine appropriate prophylactic medications to employ in the prevention of these adverse events. While several guidelines and literature exist regarding best practices for prophylaxis strategies, differences among guidelines and quality of data should be explored in order to accurately implement patient-specific recommendations. Herein, we review the existing literature for prophylaxis and summarize best practices.
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Affiliation(s)
- Amber Clemmons
- University of Georgia College of Pharmacy, Augusta, Georgia.,Augusta University Medical Center, Augusta, Georgia
| | | | | | | | - Thuy Le
- Augusta University Medical Center, Augusta, Georgia
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Clemmons A, Lebovitz L, Fulford M, Greene K, Franks A, Branan T, Plake KI. Impact of the COVID-19 pandemic on faculty at research-intensive United States schools/colleges of pharmacy. Curr Pharm Teach Learn 2022; 14:145-152. [PMID: 35190155 PMCID: PMC8711793 DOI: 10.1016/j.cptl.2021.11.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 11/18/2021] [Accepted: 11/28/2021] [Indexed: 05/29/2023]
Abstract
INTRODUCTION To describe the impact of the SARS-CoV-2 pandemic on teaching, research, practice, and work-life integration for pharmacy faculty at research-intensive institutions. METHODS An online survey related to transition to remote work, impact on faculty responsibilities, demographics, and other elements was sent to nine research-intensive United States public schools/colleges of pharmacy. Respondents were asked to describe challenges in moving to remote instruction as a result of the pandemic. The 75-item survey asked respondents to rate the degree to which factors were challenging and levels of concern with the abrupt transition. Responses were analyzed using descriptive statistics and comparison of means using paired samples t-tests between spring and fall semesters, for the types of students taught, and for faculty discipline. RESULTS Surveys were completed by 279 faculty (36% response rate), with 62% self-identifying as pharmacy practice faculty. The highest reported challenges were family/home responsibilities (41%), assisting children with schoolwork (28%), and availability of childcare (22%). Concerns most identified by respondents were increased workload, potential for academic dishonesty, and inability to effectively conduct hands-on activities. Practice faculty encountered barriers using telehealth and delivering virtual experiential education, while both practice and research faculty reported concerns with research progress. CONCLUSIONS The pandemic has led to substantial challenges and increased workload in many areas. As the pandemic persists, administration should consider reported barriers and concerns to inform expectations. Evaluation of novel instructional design, assessment methods, and best practices in the virtual learning environment is highly encouraged to ensure student competencies are met.
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Affiliation(s)
- Amber Clemmons
- University of Georgia (UGA) College of Pharmacy, 250 W. Green Street, Athens, Georgia 30602, United States.
| | - Lisa Lebovitz
- University of Maryland School of Pharmacy, 20 North Pine Street, Pharmacy Hall S303, Baltimore, MD 2120, United States.
| | - Mike Fulford
- University of Georgia (UGA) College of Pharmacy, 250 W. Green Street, Athens, Georgia 30602, United States.
| | - Kayleigh Greene
- University of Georgia (UGA) College of Pharmacy, 250 W. Green Street, Athens, Georgia 30602, United States.
| | - Andrea Franks
- University of Tennessee Health Science Center College of Pharmacy, 1924 Alcoa Highway Box 117, Knoxville, TN 37920, United States.
| | - Trisha Branan
- University of Georgia (UGA) College of Pharmacy, 250 W. Green Street, Athens, Georgia 30602, United States.
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Abstract
Recently, the required training and credentials for as well as the various roles of the hematopoietic cell transplant (HCT) pharmacist have been endorsed by the leading organizations in cellular therapy, the American Society of Transplant and Cellular Therapy and the European Society of Blood and Bone Marrow Transplantation. While these documents establish the roles a HCT pharmacist can fulfill within the multi-disciplinary team, few reports have evaluated the impact of the HCT pharmacist on clinical, financial, or quality outcomes. Further, a paucity of information has been reported on types of practice models, such as the use of collaborative practice agreements, or described effective methods to overcome the barriers to the increased utilization of HCT pharmacists. Herein, a brief summary of available information is provided to aid readers in understanding the state of the science for pharmacists practicing in this specialty with the goal to stimulate further research to justify the roles of HCT pharmacists and the correlation of such research to various outcome measures. Practitioners are encouraged to build upon this existing knowledge to create the novel integration and elevation of pharmacy practice to improve outcomes for patients, providers, and payors.
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Affiliation(s)
- Amber Clemmons
- College of Pharmacy, Department of Clinical and Administrative Pharmacy, University of Georgia, Augusta, GA 30912, USA;
- Department of Pharmacy, Augusta University Medical Center, Augusta, GA 30912, USA
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Daniels K, Clemmons A. Letermovir for Cytomegalovirus Prevention in Patients Undergoing Hematopoietic Cell Transplantation. J Adv Pract Oncol 2019; 10:730-735. [PMID: 33391856 PMCID: PMC7517777 DOI: 10.6004/jadpro.2019.10.7.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Cytomegalovirus (CMV) is a double-stranded DNA virus that infects (seropositive on screening) more than half of adults by age 40. However, reactivation of detectable viral load (CMV reactivation) typically occurs only in immunocompromised patients. Notably, CMV reactivation after allogeneic hematopoietic cell transplant (HCT) can increase treatment-related mortality almost 2-fold compared to patients who do not have reactivation. Historically, prevention of CMV reactivation mainly included the preemptive strategy of serial monitoring of viral load and initiating an antiviral once the viral load became elevated in an effort to prevent end-organ disease. The major limitations of the antiviral agents utilized in preemptive therapy are myelosuppression and renal toxicity. In 2017, a first-in-class viral terminase complex subunit inhibitor, letermovir, became the only U.S. Food & Drug Administration–approved medication to prevent CMV reactivation after allogeneic HCT (e.g., as prophylaxis). In a phase III trial, patients who were randomized to letermovir prophylactically had decreased rates of CMV viremia leading to preemptive therapy. The purpose of this article is to describe the need for safe and effective medication to prevent CMV reactivation, the clinical efficacy of letermovir, and the impact oncology advanced practitioners can play in reducing CMV reactivation in patients undergoing allogeneic HCT.
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Affiliation(s)
- Kori Daniels
- Augusta University Health System, Augusta, Georgia
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Doshi S, Waller J, Clemmons A. Prolonged Versus Short Infusion Rates of IV Magnesium in Hospitalized General Medicine Patients with Hypomagnesemia. Hosp Pharm 2018; 55:64-68. [PMID: 31983769 DOI: 10.1177/0018578718817941] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Introduction: Due to the renal handling mechanism of magnesium, prolonging the time for infusion of intravenous (IV) magnesium has been postulated to decrease magnesium requirements; however, a paucity of clinical evidence exists to support prolonging infusion rates. Objective: To assess if there is a difference in magnesium replacement required in the medicine population at an academic medical center when prolonged infusion rates (0.5 g/h) are compared to short infusion rates of > 0.5 g/h. Methods: A retrospective chart review was performed before and after implementation of the hypomagnesemia protocol (November 2015). Patients who received at least one dose of IV magnesium during hospitalization were selected from general medicine units. Primary aim was to determine if a difference exists in percent of days IV magnesium repletion required between patients receiving prolonged versus short infusion rates. Secondary objectives were to determine if a difference exists in total grams of magnesium received, percent of days magnesium levels were maintained in the optimal (1.4-2.7) and desired (2-2.7) therapeutic ranges, and incidence of hypomagnesemia (< 1.4 g/dL) and hypermagnesemia (> 2.7 g/dL). For safety, incidence of hypotension (systolic blood pressure < 90/60 mm Hg) during the magnesium infusion was recorded. Results: Totally, 45 patients were included in each cohort for a total of 90 patients to meet power. No differences existed between protocol groups for any demographic variables (all P > .05). Median infusion rate for the short infusion cohort was 1.8 g/h (range 1-2 g/h). Percent of days IV magnesium was replaced was 34.8% versus 37.8% (P = .39) in the short and prolonged infusion groups, respectively. No difference existed between groups for secondary outcomes (all P > .05). Conclusion: Prolonged magnesium infusion rates did not decrease magnesium replacement requirements. These results have been used to propose revision of our current magnesium infusion protocol to reduce infusion length.
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Borg MA, Clemmons A. Venetoclax: A Novel Treatment for Patients With del(17p) Chronic Lymphocytic Leukemia. J Adv Pract Oncol 2017; 8:647-652. [PMID: 30310726 PMCID: PMC6167086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kota V, Clemmons A, Chand A, Simmons J, Mansour J, Kolhe R, Jillella A. Congestive heart failure during induction with anthracycline-based therapy in patients with acute promyelocytic leukemia. J Community Support Oncol 2015; 12:390-3. [PMID: 25856011 DOI: 10.12788/jcso.0084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/01/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND Acute promyelocytic leukemia (APL) is a highly curable malignancy. However, 30% of patients die during therapy induction from bleeding, differentiation syndrome (DS), and/or infection. Recommendations suggest that congestive heart failure (CHF) is a presenting feature of DS. OBJECTIVE To assess the incidence of CHF during induction in patients with APL. METHODS A retrospective chart review was performed of patients diagnosed with APL from December 2004 to July 2013 and managed at Georgia Regents University Cancer Center. Baseline and follow-up ejection fractions (EF) were recorded and patients with a drop in EF during the induction period were evaluated. RESULTS Of the 40 evaluable patients, 37 received idarubicin-based chemotherapy. 16 of the 37 patients had a repeat ECHO for suspected cardiomyopathy, and 6 of the 16 patients (37.5%) demonstrated a decrease in EF (absolute drop, 10%-35%). The cardiac function recovered completely in 4 patients and partially in 1 patient. Gender, history of hypertension, and body mass index did not seem to correlate with incidence of CHF. LIMITATIONS The patient population is very small given the rarity of the disease. Present practice patterns do not routinely address CHF in the differential diagnosis. CONCLUSIONS Patients with APL are at risk for cardiac toxicity for a number of reasons, including cytokine storm and inflammatory state, use of anthracyclines, and DS. The clinical presentation of DS most commonly involves dyspnea and fluid retention, which are also symptoms of heart failure. Prompt cardiac evaluation should be undertaken to rule out CHF in APL patients who are going to receive an anthracycline-based therapy, because early intervention may result in an improved outcome.
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Affiliation(s)
- Vamsi Kota
- Winship Cancer Institute, Emory University, Atlanta, Georgia, USA.
| | - Amber Clemmons
- Georgia Regents University Cancer Center, Augusta, Georgia, USA; and University of Georgia College of Pharmacy, Athens, Georgia, USA
| | - Arati Chand
- Georgia Regents University Cancer Center, Augusta, Georgia, USA
| | - Josh Simmons
- Georgia Regents University Cancer Center, Augusta, Georgia, USA
| | - Joshua Mansour
- Department of Medicine, Georgia Regents University, Augusta, Georgia, USA
| | - Ravindra Kolhe
- Department of Pathology, Georgia Regents University, Augusta, Georgia, USA
| | - Anand Jillella
- Winship Cancer Institute, Emory University, Atlanta, Georgia, USA
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Kolhe R, Mangaonkar A, Mansour J, Clemmons A, Shaw J, Dupont B, Walczak L, Mondal A, Rojiani A, Jillella A, Kota V. Utility and impact of early t(15;17) identification by Fluorescence In Situ Hybridization (FISH) in clinical decision making for patients in Acute Promyelocytic Leukemia (APL). Int J Lab Hematol 2015; 37:515-20. [PMID: 25639817 DOI: 10.1111/ijlh.12326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 11/05/2014] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Acute Promyelocytic Leukemia (APL) is a curable malignancy with studies showing above 90% survival. However, population-based studies looking at survival suggest that approximately 30% of patients with APL die during induction. Early demonstration of t(15;17) will lead to accurate decision making regarding treatment. The aim of this project was to validate earlier time frames for the Abbott Molecular Vysis LSI promyelocytic leukemia (PML)/ retinoic acid receptor alpha (RARA) fluorescence in situ hybridization (FISH) probe (ASR 6-16 h). METHODS Twenty patients (15 APL cases and five non-APL cases) were selected for validating various hybridization times for the FISH probe. Expected normal signal pattern was two red and two green signals (2R2G), and the most common expected abnormal signal pattern was two fusion (yellow) signals, one red and one green (2F1R1G) and/or one fusion, one red and one green (1F1R1G). RESULTS The specificity of the probe ranged from 84% at 2 h, 86% at 4 h, 84% at 6 h, and 87% for overnight hybridization. The sensitivity increased from 79% at 2 h, 80% at 4 h, 81% at 6 h to 87% for overnight hybridization. CONCLUSION Based on the validation studies, we recommend reading of FISH results at the 4-h incubation mark for a preliminary diagnosis and confirmation with overnight hybridization.
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Affiliation(s)
- R Kolhe
- Department of Pathology, Georgia Regents University, Augusta, GA, USA
| | - A Mangaonkar
- Department of Internal Medicine, Georgia Regents University Cancer Center, Augusta, GA, USA
| | - J Mansour
- Department of Internal Medicine, Georgia Regents University Cancer Center, Augusta, GA, USA
| | - A Clemmons
- University of Georgia College of Pharmacy, Augusta, GA, USA
| | - J Shaw
- Department of Pathology, Georgia Regents University, Augusta, GA, USA
| | - B Dupont
- Department of Pathology, Georgia Regents University, Augusta, GA, USA
| | - L Walczak
- Department of Pathology, Georgia Regents University, Augusta, GA, USA
| | - A Mondal
- Department of Pathology, Georgia Regents University, Augusta, GA, USA
| | - A Rojiani
- Department of Pathology, Georgia Regents University, Augusta, GA, USA
| | - A Jillella
- Winship Cancer Institute of Emory University, Atlanta, GA, USA
| | - V Kota
- Winship Cancer Institute of Emory University, Atlanta, GA, USA
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Wang S, Clemmons A, Chackalamannil S, Coval SJ, Sybertz E, Burrier R. Wiedendiol-A inhibits cholesteryl ester binding to its transfer protein. Zhongguo Yao Li Xue Bao 1998; 19:408-12. [PMID: 10375797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
AIM To study the wiedendiol-A (W-A) inhibition mechanism of plasma cholesteryl ester (CE) transfer protein (CETP) on the transfer of CE. METHODS Using gel filtration method. RESULTS W-A at 30 mumol.L-1 inhibited association of CE with CETP by 76% and CETP transfer activity by 81%. In addition, W-A enhanced binding of TP2, a monoclonal antibody with a CETP C-terminal epitope which is involved in CE binding, to CETP, suggesting a W-A-induced conformational change at the epitope for increased TP2 binding. When CETP activity was measured by varying high-density lipoproteins (HDL) concentration, the apparent Vmax of CE transfer was inhibited by 74% and 83% in the presence of W-A at 14 and 25 mumol.L-1, respectively, while the apparent K(m) of HDL for CETP did not change. CONCLUSION W-A action is mediated through interaction between W-A and CETP, but not through those between W-A and lipoproteins.
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Affiliation(s)
- S Wang
- Department of CNS/CV Biological Research, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA.
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Wang S, Clemmons A, Bayne M, Graziano MP. Retrovirus-mediated expression of the GalR1 galanin receptor: implication for efficient stable expression of functional G protein-coupled receptors. J Recept Signal Transduct Res 1998; 18:311-20. [PMID: 9879063 DOI: 10.3109/10799899809047749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The rat GalR1 galanin receptor was used as a prototypic G protein-coupled receptor to test the feasibility of heterologous expression in a retrovirus-based system. The system utilizes an independent retroviral vector pMX, a virus-packaging cell line BOSC23 and a pre-B cell line BA/F3 as the host for expression. A polyclonal cell population that expresses high ligand affinity (KD = 0.18 nM) and high level (7 pmol/mg) of GalR1 was generated within days with no drug sensitivity-based selection. The expression represented a 20-fold increase over the expression level of GalR1 achieved in CHO cells. The affinity of galanin for the expressed receptor was decreased by 19-fold in the presence of GTP-gamma-S, suggesting that the expression system can produce active galanin receptor functionally coupled to G proteins. The fast and efficient method to generate stable cell lines and to prepared large quantities of receptors may provide a general application for expression of other G protein-coupled receptors.
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Affiliation(s)
- S Wang
- Department of CNS/CV Biological Research, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA
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Wang S, Clemmons A, Strader C, Bayne M. Evidence for hydrophobic interaction between galanin and the GalR1 galanin receptor and GalR1-mediated ligand internalization: fluorescent probing with a fluorescein-galanin. Biochemistry 1998; 37:9528-35. [PMID: 9649336 DOI: 10.1021/bi9731955] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Galanin is a neuropeptide that activates specific receptors to modulate several physiological functions including food intake, nociception, and learning and memory. The molecular nature of the interaction between galanin and its receptors and the fate of the galanin/receptor complex after the binding event are not understood. A fluorescein-N-galanin (F-Gal) was generated to measure the interaction between galanin and rat GalR1 galanin receptor (rGalR1) and rGalR1-mediated ligand internalization using flow cytometry in transfected Chinese hamster ovary (CHO) cells. Like galanin, F-Gal bound rGalR1 with high affinity and stimulated intracellular signaling events. Fluorescence quenching by soluble KI of rGalR1-bound F-Gal revealed a highly protected environment around the fluorescein, suggesting that the N-terminal portion of galanin, which constitutes the binding site of galanin for the receptor, binds to a protected hydrophobic binding pocket within the receptor. Exposure to F-Gal stimulated rapid (t1/2 approximately 10 min) and extensive (78%) internalization of surface F-Gal into rGalR1/CHO cells at 37 degreesC but not at 0 degreesC. In addition, the internalization did not occur in parental CHO cells at either 0 or 37 degreesC and was inhibited by addition of 0.25 M sucrose in the medium, indicating a GalR1-mediated energy-requiring endocytic process. These results revealed a hydrophobic interaction between galanin and the GalR1 receptor, which is in contrast to those of other G protein-coupled receptors that mainly require hydrophilic interaction with their peptide ligands near or outside the plasma membrane surface, and illustrated that the initial binding interaction is followed by rapid cellular internalization of the agonist/GalR1 complex.
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Affiliation(s)
- S Wang
- Department of CNS/CV Biological Research, Schering-Plough Research Institute, Kenilworth, New Jersey 07033,
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