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Brabender D, Siegel E, Culver J, Comeaux J, Date A, Woodworth A. EPR24-111: The Clinical Effect of a Community-Based Genetic Testing Program. J Natl Compr Canc Netw 2024; 22:EPR24-111. [PMID: 38580284 DOI: 10.6004/jnccn.2023.7227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Affiliation(s)
- Danielle Brabender
- 1Keck School of Medicine of USC, University of Southern California, Los Angeles, CA
| | - Emily Siegel
- 1Keck School of Medicine of USC, University of Southern California, Los Angeles, CA
| | - Julie Culver
- 1Keck School of Medicine of USC, University of Southern California, Los Angeles, CA
| | - Jacob Comeaux
- 1Keck School of Medicine of USC, University of Southern California, Los Angeles, CA
| | - Anjali Date
- 2Henry Mayo Newhall Hospital, Santa Clarita, CA
| | - Amanda Woodworth
- 1Keck School of Medicine of USC, University of Southern California, Los Angeles, CA
- 2Henry Mayo Newhall Hospital, Santa Clarita, CA
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2
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Schneider M, Woodworth A, Ericson M, Boerger L, Denne S, Dillon P, Duguid P, Ghanem E, Hunt J, Li JS, McCoy R, Prokofieva N, Rodriguez V, Sparks C, Zaleski J, Xiang H. Distinguishing between translational science and translational research in CTSA pilot studies: A collaborative project across 12 CTSA hubs. J Clin Transl Sci 2023; 8:e4. [PMID: 38384905 PMCID: PMC10877521 DOI: 10.1017/cts.2023.700] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 02/23/2024] Open
Abstract
Introduction The institutions (i.e., hubs) making up the National Institutes of Health (NIH)-funded network of Clinical and Translational Science Awards (CTSAs) share a mission to turn observations into interventions to improve public health. Recently, the focus of the CTSAs has turned increasingly from translational research (TR) to translational science (TS). The current NIH Funding Opportunity Announcement (PAR-21-293) for CTSAs stipulates that pilot studies funded through the CTSAs must be "focused on understanding a scientific or operational principle underlying a step of the translational process with the goal of developing generalizable solutions to accelerate translational research." This new directive places Pilot Program administrators in the position of arbiters with the task of distinguishing between TR and TS projects. The purpose of this study was to explore the utility of a set of TS principles set forth by NCATS for distinguishing between TR and TS. Methods Twelve CTSA hubs collaborated to generate a list of Translational Science Principles questions. Twenty-nine Pilot Program administrators used these questions to evaluate 26 CTSA-funded pilot studies. Results Factor analysis yielded three factors: Generalizability/Efficiency, Disruptive Innovation, and Team Science. The Generalizability/Efficiency factor explained the largest amount of variance in the questions and was significantly able to distinguish between projects that were verified as TS or TR (t = 6.92, p < .001) by an expert panel. Conclusions The seven questions in this factor may be useful for informing deliberations regarding whether a study addresses a question that aligns with NCATS' vision of TS.
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Affiliation(s)
- Margaret Schneider
- The Institute for Clinical and Translational Science, University of
California, Irvine, CA, USA
| | - Amanda Woodworth
- The Institute for Clinical and Translational Science, University of
California, Irvine, CA, USA
| | - Marissa Ericson
- The Institute for Clinical and Translational Science, University of
California, Irvine, CA, USA
| | - Lindsie Boerger
- The Institute of Translational Health Sciences, University of
Washington, Seattle, WA, USA
| | - Scott Denne
- The Indiana Clinical and Translational Sciences Institute, Indiana
University, Indianapolis, IN,
USA
| | - Pam Dillon
- The Wright Center for Clinical and Translational Research,
Virginia Commonwealth University, Richmond,
VA, USA
| | - Paul Duguid
- The Translational Research Institute, University of Arkansas Medical
Sciences, Little Rock, AR,
USA
| | - Eman Ghanem
- Duke Clinical & Translational Science Institute, Duke
University, Durham, NC, USA
| | - Joe Hunt
- The Indiana Clinical and Translational Sciences Institute, Indiana
University, Indianapolis, IN,
USA
| | - Jennifer S. Li
- Duke Clinical & Translational Science Institute, Duke
University, Durham, NC, USA
| | - Renee McCoy
- Clinical & Translational Science Institute of Southeast Wisconsin, Medical
College of Wisconsin, Milwaukee, WI,
USA
| | - Nadia Prokofieva
- Tufts Clinical and Translational Science Institute, Tufts
University, Boston, MA, USA
| | - Vonda Rodriguez
- Duke Clinical & Translational Science Institute, Duke
University, Durham, NC, USA
| | - Crystal Sparks
- The Translational Research Institute, University of Arkansas Medical
Sciences, Little Rock, AR,
USA
| | - Jeffrey Zaleski
- The Indiana Clinical and Translational Sciences Institute, Indiana
University, Indianapolis, IN,
USA
| | - Henry Xiang
- Center for Clinical and Translational Science, The Ohio State
University, Columbus, OH, USA
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Mavragani A, Woodworth A, Mehrabadi MA. The Relationship Between Exercise Habits and Stress Among Individuals With Access to Internet-Connected Home Fitness Equipment: Single-Group Prospective Analysis. JMIR Form Res 2023; 7:e41877. [PMID: 36719817 PMCID: PMC9947760 DOI: 10.2196/41877] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Physical activity (PA) confers numerous benefits to health and health care costs, yet most adults are not meeting recommended PA guidelines. Stress may be a factor that influences PA behavior. Research investigating the impact of stress on PA has yielded inconsistent findings. Most studies find that stress negatively impacts PA, but there is some evidence that habitual exercising buffers this association. OBJECTIVE This study aims to examine the relationship between stress and exercise habits among habitual exercisers with internet-connected home fitness equipment (Peloton Bike) during the COVID-19 lockdown. METHODS Participants were recruited through Facebook (N=146) and asked to complete an internet-based survey that assessed COVID-19-related stressors, perceived stress associated with those stressors, and general perceived stress. Self-reported exercise was assessed on the survey using the Godin Leisure-time Exercise Questionnaire (GLTEQ). Participants were also asked for consent to access their Peloton usage data through the Peloton platform. From their usage data, the frequency and duration of cycling classes was calculated for 4 weeks prior to and 12 weeks following the survey. Hierarchical regression equations tested the association between stress reported on the survey and subsequent exercise participation. Exercise participation was quantified both as the frequency and duration of Peloton cycling over the 12 weeks following the survey and as self-reported moderate to vigorous activity on a second survey completed by a subset of participants 12 weeks after the initial survey. RESULTS There were 146 participants in our Peloton analysis sample and 66 in the self-reported exercise analysis. Peloton user data showed that study participants cycled frequently (mean 5.9 times per week) in the month prior to the initial survey, and that presurvey Peloton use was a strong predictor of exercise frequency (R2=0.57; F2,143=95.27; P<.001) and duration (R2=0.58; F2,143=102.58; P<.001) for the 12 subsequent weeks. Self-reported overall exercise likewise showed that this sample was very active, with an average of more than 8 times per week of moderate to vigorous exercise at the initial survey. Self-reported exercise on the initial survey was a strong predictor of self-reported exercise 12 weeks later (R2=0.31; F1,64=29.03; P<.001). Perceived stress did not impact Peloton cycling duration or frequency (P=.81 and .76, respectively) or self-reported exercise (P=.28). CONCLUSIONS The results suggest that stress did not negatively impact exercise participation among habitually active adults with access to internet-connected home fitness equipment. Habitual exercise may buffer the impact of stress on participation in regular moderate to vigorous activity. Future research should examine the role that the availability of home-based internet-connected exercise equipment may play in this buffering.
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Affiliation(s)
| | - Amanda Woodworth
- Institute for Clinical and Translational Science, University of California, Irvine, Irvine, CA, United States
| | - Milad Asgari Mehrabadi
- Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA, United States
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Campo M, Miovsky N, Schnieder M, Woodworth A, DeHaven M, Kahn P, Weiss M, Cooper D. Formative Evaluation of a Student Symptom Decision Tree for COVID-19. Health Behav Policy Rev 2023; 10:1140-1152. [PMID: 37143571 PMCID: PMC10156065 DOI: 10.14485/hbpr.10.1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Objective: In support of restarting during the COVID-19 pandemic, some schools partnered with local experts in academia, education, community, and public health to provide decision-support tools for determining what actions to take when presented with students at risk for spreading infection at school. Methods: The Student Symptom Decision Tree, developed in Orange County, California, is a flow chart consisting of branching logic and definitions to assist school personnel in making decisions regarding possible COVID-19 cases in schools, which was repeatedly updated to reflect evolving evidence-based guidelines. A survey of 56 school personnel evaluated the frequency of use, acceptability, feasibility, appropriateness, usability, and helpfulness of the Decision Tree. Results: The tool was used at least 6 times a week by 66% of respondents. The Decision Tree was generally perceived as acceptable (91%), feasible (70%), appropriate (89%), usable (71%), and helpful (95%). Suggestions for improvement included reducing the complexity in content and formatting of the tool. Conclusion: The data suggest that school personnel found value in the Decision Tree, which was intended to assist them with making decisions in a challenging and evolving pandemic.
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Schneider M, Woodworth A, Arumalla S, Gowder C, Hernandez J, Kim A, Moorthy B. Development of a tool for quantifying need-supportive coaching in technology-mediated exercise classes. Psychol Sport Exerc 2023; 64:102321. [PMID: 37665807 DOI: 10.1016/j.psychsport.2022.102321] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/15/2022] [Accepted: 10/13/2022] [Indexed: 09/06/2023]
Abstract
Technology-mediated interventions to promote physical activity are growing in popularity and appear to be effective for supporting continued adherence for some people. Some of this efficacy may be related to the cultivation of motivation that is self-determined (i.e., autonomous), which is posited to arise from the satisfaction of three basic psychological needs: competence, relatedness, and autonomy. We developed an observational coding tool for quantifying the frequency of needs-supportive and needs-indifferent coaching during technology-mediated exercise classes. The Peloton Instructor Needs-Supportive Coaching (PINC) tool shows evidence of reliability (average kappa = .91). We also demonstrated the utility of the PINC for characterizing needs-supportive coaching profiles across 4 different types of classes (Beginner, Power Zone, Groove, and High-Intensity Interval Training) and the construct validity of the PINC with respect to examining the relationship of needs-supportive coaching to intrinsic motivation. The PINC offers a useful tool with which future studies could evaluate whether and how instructor coaching impacts self-determined motivation to exercise within a technology-mediated context.
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Affiliation(s)
- Margaret Schneider
- Department of Population Health and Disease Prevention, University of California, Irvine, USA.
| | - Amanda Woodworth
- Institute for Clinical and Translational Science, University of California, Irvine, USA
| | - Sathvika Arumalla
- Department of Population Health and Disease Prevention, University of California, Irvine, USA
| | - Conor Gowder
- School of Social Ecology, University of California, Irvine, USA
| | - Julissa Hernandez
- Department of Population Health and Disease Prevention, University of California, Irvine, USA
| | - Ashley Kim
- Department of Population Health and Disease Prevention, University of California, Irvine, USA
| | - Brinthy Moorthy
- Department of Cognitive Sciences, University of California, Irvine, USA
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6
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Popnikolov N, Brzezinska K, Platoff RM, Binnebose R, Rothstein-Rubin R, Komarnicky LT, Woodworth A. Upregulation of Prolactin Receptor Expression and Activation of Prolactin Signaling in an Aggressive Triple-Negative Breast Carcinoma During Pregnancy: A Case Report. Clin Breast Cancer 2020; 20:e529-e539. [PMID: 32360085 DOI: 10.1016/j.clbc.2020.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 03/07/2020] [Accepted: 03/25/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Nikolay Popnikolov
- Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA.
| | - Katarzyna Brzezinska
- Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA
| | - Rebecca M Platoff
- Department of Surgery, Drexel University College of Medicine, Philadelphia, PA
| | - Rhonda Binnebose
- Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Philadelphia, PA
| | | | - Lydia T Komarnicky
- Department of Radiation Oncology, Drexel University College of Medicine, Philadelphia, PA
| | - Amanda Woodworth
- Department of Surgery, Drexel University College of Medicine, Philadelphia, PA
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Moore J, Galbraith J, Cox A, Furr K, Smith N, Cleland D, Woodworth A, Howard P, Dai C, Humphries R. 14 Nontargeted Hepatitis C Virus Screening in an Appalachian Emergency Department Identifies a High Prevalence of Infection Among Adult Emergency Department Visitors. Ann Emerg Med 2019. [DOI: 10.1016/j.annemergmed.2019.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Schwartz J, Lentini AR, Woodworth A. Borderline Malignant Phyllodes Tumor in a 12-Year-Old: Applying Oncoplastic Principles to Adolescents. Am Surg 2019; 85:e252-e253. [PMID: 31126380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
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Affiliation(s)
- Jandie Schwartz
- Department of Surgery Inspira Health Network Vineland, New Jersey
| | - Ashley R. Lentini
- Department of Pathology Drexel University College of Medicine Philadelphia, Pennsylvania
| | - Amanda Woodworth
- Department of Surgery Drexel University College of Medicine Philadelphia, Pennsylvania
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Remmert JE, Woodworth A, Chau L, Schumacher LM, Butryn ML, Schneider M. Pilot Trial of an Acceptance-Based Behavioral Intervention to Promote Physical Activity Among Adolescents. J Sch Nurs 2018; 35:449-461. [PMID: 30004269 DOI: 10.1177/1059840518786782] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [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: 11/16/2022] Open
Abstract
Prior interventions have shown limited efficacy in increasing the number of adolescents engaging in adequate physical activity (PA). Preliminary evidence suggests acceptance-based behavioral treatments (ABTs) may increase PA; however, this approach has not been tested in adolescents. This was a nonrandomized experimental pilot study that examined feasibility, acceptability, and treatment outcomes of a school-based, acceptance-based behavioral intervention for PA. Adolescents (n = 20) with low activity received a PA tracking device and were allocated to device use only or device use plus 10-weeks of ABT. PA, cardiovascular fitness, and physiological outcomes were measured pre- and postintervention. The intervention was found to be feasible and acceptable. PA, cardiovascular fitness, and physiological outcomes improved over time in the intervention group, but not in the comparison condition. This study demonstrated feasibility, acceptability, and preliminary treatment efficacy based on effect sizes for an acceptance-based behavioral intervention to increase PA in adolescents.
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Affiliation(s)
- Jocelyn E Remmert
- Department of Psychology, Center for Weight, Eating, and Lifestyle Science, Drexel University, Philadelphia, PA, USA
| | | | | | - Leah M Schumacher
- Department of Psychology, Center for Weight, Eating, and Lifestyle Science, Drexel University, Philadelphia, PA, USA
| | - Meghan L Butryn
- Department of Psychology, Center for Weight, Eating, and Lifestyle Science, Drexel University, Philadelphia, PA, USA
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Woodworth A, Ferris P, Falkenholt K, Wigbers A, Niedo E. LESSONS LEARNED AT THE BEDSIDE: CARING FOR TRANSCATHETER AORTIC VALVE IMPLANTATION PATIENTS. Can J Cardiol 2014. [DOI: 10.1016/j.cjca.2014.07.640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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12
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Woodworth A, Khanmoradi K, Zaki R, Campos S, Horrow M, Ortiz J. Median arcuate ligament syndrome with early collateralization in a liver transplant. Am Surg 2010; 76:E156-E157. [PMID: 21396270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Woodworth A, Khanmoradi K, Zaki R, Campos S, Horrow M, Ortiz J. Median Arcuate Ligament Syndrome with Early Collateralization in a Liver Transplant. Am Surg 2010. [DOI: 10.1177/000313481007600905] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Amanda Woodworth
- Division of Transplantation Department of Surgery Albert Einstein Medical Center Philadelphia, Pennsylvania
| | - Kamran Khanmoradi
- Division of Transplantation Department of Surgery Albert Einstein Medical Center Philadelphia, Pennsylvania
| | - Radi Zaki
- Division of Transplantation Department of Surgery Albert Einstein Medical Center Philadelphia, Pennsylvania
| | - Stalin Campos
- Division of Transplantation Department of Surgery Albert Einstein Medical Center Philadelphia, Pennsylvania
| | - Mindy Horrow
- Division of Transplantation Department of Surgery Albert Einstein Medical Center Philadelphia, Pennsylvania
| | - Jorge Ortiz
- Division of Transplantation Department of Surgery Albert Einstein Medical Center Philadelphia, Pennsylvania
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Affiliation(s)
- A Woodworth
- Department of Pathology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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15
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Loh SF, Woodworth A, Yeo GS. Umbilical cord blood gas analysis at delivery. Singapore Med J 1998; 39:151-5. [PMID: 9676144] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND Umbilical cord blood gas values are better indicators of perinatal asphyxia than Apgar scores. However, the reported normal range of umbilical blood gas values vary greatly in the literature. The aim of this prospective study was to establish the normal range of umbilical cord blood gas values in our labour ward. METHODS AND RESULTS Umbilical cord blood gas from 153 vaginal deliveries and 52 Caesarean sections for indication other than fetal distress were evaluated. In our labour ward, the mean and standard deviation of umbilical artery pH were 7.21 and 0.08 for vaginal deliveries and 7.22 and 0.07 for Caesarean sections respectively. The mean and standard deviation for umbilical artery base deficit were 5.08 and 3.85 for vaginal deliveries and 4.09 and 3.07 for Caesarean sections respectively. CONCLUSION In conclusion, pH of 7.05 is the statistical lower limit of umbilical artery pH in our labour ward and is a good cut-off value to indicate perinatal asphyxia. Five cases with abnormal umbilical artery pH (< 7.05) were also analysed and discussed.
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Affiliation(s)
- S F Loh
- Department of Maternal-Fetal Medicine, KK Women's and Children's Hospital, Singapore
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Tew KD, Woodworth A, Stearns ME. Relationship of glutathione depletion and inhibition of glutathione-S-transferase activity to the antimitotic properties of estramustine. Cancer Treat Rep 1986; 70:715-20. [PMID: 3731136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A depletion of intracellular glutathione (GSH) is accompanied by a subsequent inhibition of GSH-S-transferase activity in a DU145 human prostatic carcinoma cell line treated with cytotoxic concentrations of estramustine. When GSH depletion reached approximately 50% of normal (approximately 2 hours after 10 microM estramustine), the mitotic index of logarithmically dividing cultures began to increase. A linear increase from 3.14% to 22.5% occurred during the period of 2-24 hours following 10 microM estramustine. Morphological studies showed that mitotic figures accumulated in metaphase and had abnormalities consistent with spindle malformation. Nocodazole and cytochalasin B also possess anticytoskeletal properties, but had little effect upon the intracellular levels of GSH or its associated transferase enzymes. The constituent moieties of estramustine, estradiol, and nor-mechlorethamine had effects on thiol metabolism which were dissimilar from estramustine, confirming previous findings that the unmetabolized parent drug is responsible for pharmacological activity. Estramustine had no effect upon GSH reductase activity, suggesting that drug toxicity was not a general thiol phenomenon. Buthionine sulfoximine decreased intracellular GSH in DU145 cells and enhanced the cytotoxic potential of estramustine in this cell line. The anticytoskeletal and antimitotic properties of estramustine may be enhanced by the drug-induced GSH imbalance and subsequent effects on GSH-S-transferase enzymes.
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Zigmond SH, Woodworth A, Daukas G. Effects of sodium on chemotactic peptide binding to polymorphonuclear leukocytes. The Journal of Immunology 1985. [DOI: 10.4049/jimmunol.135.1.531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Abstract
The affinity of binding of the chemotactic peptide N-formylnorleucylleucylphenylalanine to rabbit peritoneal polymorphonuclear leukocytes is increased when sodium ions are removed from the medium. In Hanks' balanced salt solution, the dissociation constant of the binding is about 2 X 10(-8) M, while in Na+-free medium, the dissociation constant is between 3 and 6 X 10(-9) M. Removal of Na+ appears to cause little or no change in receptor number. The change in affinity is rapid and reversible, occurs at 4 degrees C as well as 37 degrees C, and occurs when the Na+ is replaced by K+, choline, or sucrose. The increased binding of low concentrations of peptide is seen on broken as well as whole cells and therefore does not depend on an ion gradient across the membrane. The high affinity receptors are functional in mediating peptide uptake and lysosomal enzyme release. The receptors undergo down-regulation in Na+-free medium, and the dose dependence of the receptor loss is shifted to lower concentrations consistent with the higher affinity of the binding.
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Zigmond SH, Woodworth A, Daukas G. Effects of sodium on chemotactic peptide binding to polymorphonuclear leukocytes. J Immunol 1985; 135:531-6. [PMID: 2582048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The affinity of binding of the chemotactic peptide N-formylnorleucylleucylphenylalanine to rabbit peritoneal polymorphonuclear leukocytes is increased when sodium ions are removed from the medium. In Hanks' balanced salt solution, the dissociation constant of the binding is about 2 X 10(-8) M, while in Na+-free medium, the dissociation constant is between 3 and 6 X 10(-9) M. Removal of Na+ appears to cause little or no change in receptor number. The change in affinity is rapid and reversible, occurs at 4 degrees C as well as 37 degrees C, and occurs when the Na+ is replaced by K+, choline, or sucrose. The increased binding of low concentrations of peptide is seen on broken as well as whole cells and therefore does not depend on an ion gradient across the membrane. The high affinity receptors are functional in mediating peptide uptake and lysosomal enzyme release. The receptors undergo down-regulation in Na+-free medium, and the dose dependence of the receptor loss is shifted to lower concentrations consistent with the higher affinity of the binding.
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