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Susey K, Hanin M, Wortner A, Mandich M, Scott K, Stephenson K, Shepherd E, Mehling M. Validity and reliability of the behavioral signs of respiratory instability (BSRI) © scale during activity for infants with bronchopulmonary dysplasia. J Perinatol 2023; 43:1015-1019. [PMID: 37185368 PMCID: PMC10129300 DOI: 10.1038/s41372-023-01682-9] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/17/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023]
Abstract
OBJECTIVE There is no reliable evidence on how best to evaluate the overall status of infants with severe forms of bronchopulmonary dysplasia (BPD). The Behavioral Signs of Respiratory Instability (BSRI) scale was developed as an objective measure of developmental capacity during occupational and physical therapy sessions. The purpose of this study was to determine the psychometric properties of the BSRI Scale. STUDY DESIGN The BSRI and Respiratory Severity Score (RSS) were compared for 25 infants with BPD and 15 infants without BPD. A cross-sectional design was used to test inter-rater reliability among 10 NICU occupational and physical therapists. A prospective cohort design was used to evaluate validity. RESULTS The BSRI demonstrated good to excellent inter-rater reliability (ρ = 0.47-0.91) and was strongly correlated with RSS (ρ = -0.77, p < 0.001; concurrent validity). CONCLUSION The BSRI Scale has preliminary psychometric support. Standardized measures like the BSRI may provide accurate, objective data that can improve care planning within interdisciplinary teams that supports brain growth and potentially improves neurodevelopment.
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Affiliation(s)
- K Susey
- Neonatal Therapy Department, Nationwide Children's Hospital, Columbus, OH, USA.
| | - M Hanin
- Neonatal Therapy Department, Nationwide Children's Hospital, Columbus, OH, USA
| | - A Wortner
- Neonatal Therapy Department, Nationwide Children's Hospital, Columbus, OH, USA
| | - M Mandich
- Division of Physical Therapy, West Virginia University, Morgantown, WV, USA
| | - K Scott
- School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH, USA
| | - K Stephenson
- Department of Psychology, Nationwide Children's Hospital, Columbus, OH, USA
| | - E Shepherd
- Comprehensive Center for Bronchopulmonary Dysplasia, Nationwide Children's Hospital, Columbus, OH, USA
| | - M Mehling
- Department of Psychology, Nationwide Children's Hospital, Columbus, OH, USA
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Baumberger K, Busby C, Mascarella A, McKinzie C, Stephenson K, Kam C. 208 Fat-soluble vitamin level trends after elexacaftor/tezacaftor/ivacaftor therapy. J Cyst Fibros 2022. [DOI: 10.1016/s1569-1993(22)00898-0] [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: 11/05/2022]
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Weller SA, Armstrong SR, Bailey S, Burnell HT, Burt EL, Cant NE, Cawthorne KR, Chester M, Choules JE, Coe NA, Coward L, Cox VL, Emery ER, Evans CP, Finn A, Halford CM, Hamblin KA, Harrison GV, Hartley MG, Hudson C, James B, Jones HE, Keyser E, Lonsdale CL, Marshall LE, Maule CE, Miles JA, Newstead SL, Nicholls M, Osborne C, Pearcy AS, Penny LD, Perrot R, Rachwal P, Robinson V, Rushton D, Stahl FM, Staplehurst SV, Stapleton HL, Steeds K, Stephenson K, Thompson IJ, Thwaite JE, Ulaeto DO, Waters N, Wills DJ, Wills ZS, Rees C, Hutley EJ. Development and operation of the defence COVID-19 lab as a SARS-CoV-2 diagnostic screening capability for UK military personnel. BMJ Mil Health 2022; 170:e002134. [PMID: 35878971 PMCID: PMC10958320 DOI: 10.1136/military-2022-002134] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/03/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND In the face of the COVID-19 pandemic, the Defence Science and Technology Laboratory (Dstl) and Defence Pathology combined to form the Defence Clinical Lab (DCL), an accredited (ISO/IEC 17025:2017) high-throughput SARS-CoV-2 PCR screening capability for military personnel. LABORATORY STRUCTURE AND RESOURCE The DCL was modular in organisation, with laboratory modules and supporting functions combining to provide the accredited SARS-CoV-2 (envelope (E)-gene) PCR assay. The DCL was resourced by Dstl scientists and military clinicians and biomedical scientists. LABORATORY RESULTS Over 12 months of operation, the DCL was open on 289 days and tested over 72 000 samples. Six hundred military SARS-CoV-2-positive results were reported with a median E-gene quantitation cycle (Cq) value of 30.44. The lowest Cq value for a positive result observed was 11.20. Only 64 samples (0.09%) were voided due to assay inhibition after processing started. CONCLUSIONS Through a sustained effort and despite various operational issues, the collaboration between Dstl scientific expertise and Defence Pathology clinical expertise provided the UK military with an accredited high-throughput SARS-CoV-2 PCR test capability at the height of the COVID-19 pandemic. The DCL helped facilitate military training and operational deployments contributing to the maintenance of UK military capability. In offering a bespoke capability, including features such as testing samples in unit batches and oversight by military consultant microbiologists, the DCL provided additional benefits to the UK Ministry of Defence that were potentially not available from other SARS-CoV-2 PCR laboratories. The links between Dstl and Defence Pathology have also been strengthened, benefitting future research activities and operational responses.
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Affiliation(s)
- Simon A Weller
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - S R Armstrong
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - S Bailey
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - H T Burnell
- Operations Division, Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| | - E L Burt
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - N E Cant
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - K R Cawthorne
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - M Chester
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - J E Choules
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - N A Coe
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - L Coward
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - V L Cox
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - E R Emery
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - C P Evans
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - A Finn
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - C M Halford
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - K A Hamblin
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - G V Harrison
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - M G Hartley
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - C Hudson
- Defence Pathology, Royal Centre for Defence Medicine, Birmingham, UK
| | - B James
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - H E Jones
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - E Keyser
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - C L Lonsdale
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - L E Marshall
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - C E Maule
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - J A Miles
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - S L Newstead
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - M Nicholls
- Defence Pathology, Royal Centre for Defence Medicine, Birmingham, UK
| | - C Osborne
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - A S Pearcy
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - L D Penny
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - R Perrot
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - P Rachwal
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - V Robinson
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - D Rushton
- Platform Systems Division, Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| | - F M Stahl
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - S V Staplehurst
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - H L Stapleton
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - K Steeds
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - K Stephenson
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - I J Thompson
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - J E Thwaite
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - D O Ulaeto
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - N Waters
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - D J Wills
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - Z S Wills
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - C Rees
- CBR Division, Defence Science and Technology Laboratory Porton Down, Salisbury, UK
| | - E J Hutley
- Defence Pathology, Royal Centre for Defence Medicine, Birmingham, UK
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Stephenson K, O’Hara M, Holland C, Womble M, Jennings S, Weber Rawlins M, Elbin RJ. A-45 Clinical Considerations of Neuropsychologists for Treating Concussions. Arch Clin Neuropsychol 2022. [DOI: 10.1093/arclin/acac32.45] [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: 11/14/2022] Open
Abstract
Abstract
Purpose: The purpose of this study was to explore sex specific clinical considerations by neuropsychologists’ and general clinical considerations for the treatment of concussion. Methods: Fourteen clinical neuropsychologists who see concussion patients regularly (>1 case per week) were interviewed using a semi-structured guide that included a generic patient vignette. Participants were asked about clinical considerations that they faced while assessing, managing, and treating concussion. Two investigators independently coded the transcriptions and met to compare coding processes, definitions, and categories. A final codebook was developed in an iterative fashion and reapplied to all transcripts. Independent coding and member checks contributed to the trustworthiness of the data. Results: Participants’ clinical experience in treating concussion ranged from 1 to 40 years, and the sample was 64% female (9/14). Four major themes were identified, including patients’ sex considerations, sleep and napping, patient education and reassurance, and mental health considerations. Several participants (4/14; 29%) noted the lack of action-oriented clinical recommendations for previously documented sex differences (i.e., menstruation). There was a lack of uniformity in sleep and napping recommendations across the participants (e.g., permitting napping vs recommended nap-length). Participants noted that a large portion of their clinical time was spent educating and reassuring patients that concussion is treatable. Comorbid mental health considerations such as anxiety were a prevailing clinical concern across participants. Conclusions: The study revealed the need for better action-oriented clinical recommendations in consensus statements that address the four main themes of sex considerations, sleep and napping considerations, patient education and reassurance, and mental health considerations.
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Fleming PM, Stephenson K, Collick AS, Easton ZM. Targeting for nonpoint source pollution reduction: A synthesis of lessons learned, remaining challenges, and emerging opportunities. J Environ Manage 2022; 308:114649. [PMID: 35144063 DOI: 10.1016/j.jenvman.2022.114649] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [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: 07/28/2021] [Revised: 12/23/2021] [Accepted: 01/31/2022] [Indexed: 06/14/2023]
Abstract
The ability to identify, target, and treat critical pollution source areas on a landscape is an ongoing challenge for water quality programs that seek to address nonpoint source (NPS) pollution. In this article, we develop a conceptual framework for targeting program design, and review recent experience with the implementation of targeting programs that corresponds with a wide range of program characteristics. Through this review, we emphasize that the complex and locally dependent nature of NPS generation and transport makes it impossible to define a narrow set of rules to guide targeting programs everywhere. Instead, we evaluate key features of NPS targeting in several different contexts, highlighting lessons learned from recent experience. This synthesis of targeting program design and implementation points toward several areas of opportunity for improved NPS policy, however more research is needed to systematically document changes in behavior and pollutant loads. The lack of monitoring data at refined scales presents a major obstacle to targeting program success. This paper synthesizes new opportunities and ongoing challenges for the implementation of targeting in NPS water quality programs.
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Affiliation(s)
- P M Fleming
- Department of Economics and Public Policy, Franklin and Marshall College, Lancaster, PA, 17604, USA.
| | - K Stephenson
- Department of Agricultural and Applied Economics, Virginia Tech, Blacksburg, VA, 24061, USA
| | - A S Collick
- Department of Agricultural Sciences, Morehead State University Morehead, KY, 40351, USA
| | - Z M Easton
- Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
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McGray AJR, Eppolito C, Miliotto A, Singel KL, Stephenson K, Lugade A, Segal BH, Keler T, Webster G, Lichty B, Kozbor D, Odunsi K. A prime/boost vaccine platform efficiently identifies CD27 agonism and depletion of myeloid-derived suppressor cells as therapies that rationally combine with checkpoint blockade in ovarian cancer. Cancer Immunol Immunother 2021; 70:3451-3460. [PMID: 33880648 PMCID: PMC8057655 DOI: 10.1007/s00262-021-02936-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/31/2021] [Indexed: 12/30/2022]
Abstract
Cancer immunotherapies have generated remarkable clinical responses for some patients with advanced/metastatic disease, prompting exploration of rational combination therapies to bolster anti-tumor immunity in patients with limited response or those who experience tumor progression following an initial response to immunotherapy. In contrast to other tumor indications, objective response rates to single-agent PD-1/PD-L1 blockade in ovarian cancer are limited, suggesting a need to identify combinatorial approaches that lead to tumor regression in a setting where checkpoint blockade alone is ineffective. Using a pre-clinical model of aggressive intraperitoneal ovarian cancer, we have previously reported on a heterologous prime/boost cancer vaccine that elicits robust anti-tumor immunity, prolongs survival of tumor-bearing mice, and which is further improved when combined with checkpoint blockade. As tumor control in this model is CD8 + T cell dependent, we reasoned that the prime/boost vaccine platform could be used to explore additional treatment combinations intended to bolster the effects of CD8 + T cells. Using whole tumor transcriptomic data, we identified candidate therapeutic targets anticipated to rationally combine with prime/boost vaccination. In the context of a highly effective cancer vaccine, CD27 agonism or antibody-mediated depletion of granulocytic cells each modestly increased tumor control following vaccination, with anti-PD-1 therapy further improving treatment efficacy. These findings support the use of immunotherapies with well-defined mechanisms(s) of action as a valuable platform for identifying candidate combination approaches for further therapeutic testing in ovarian cancer.
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Affiliation(s)
- A J R McGray
- Center for Immunotherapy, Roswell Park Comprehensive Cancer Center, Roswell Park Cancer Institute, Elm and Carlton Sts, Buffalo, NY, 14263, USA.
| | - C Eppolito
- Center for Immunotherapy, Roswell Park Comprehensive Cancer Center, Roswell Park Cancer Institute, Elm and Carlton Sts, Buffalo, NY, 14263, USA
| | - A Miliotto
- Center for Immunotherapy, Roswell Park Comprehensive Cancer Center, Roswell Park Cancer Institute, Elm and Carlton Sts, Buffalo, NY, 14263, USA
| | - K L Singel
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
- Office of Evaluation, Performance, and Reporting, National Institutes of Health, Bethesda, MD, USA
| | - K Stephenson
- McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada
- Turnstone Biologics, Ottawa, ON, Canada
| | - A Lugade
- Center for Immunotherapy, Roswell Park Comprehensive Cancer Center, Roswell Park Cancer Institute, Elm and Carlton Sts, Buffalo, NY, 14263, USA
| | - B H Segal
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
- Department of Internal Medicine, Roswell Park Comprehensive Cancer Center and Jacobs School of Medicine and Biomedical Sciences, University At Buffalo, Buffalo, NY, USA
| | - T Keler
- Celldex Therapeutics, Hampton, NJ, USA
| | - G Webster
- Innate Immunotherapeutics, Auckland, New Zealand
| | - B Lichty
- McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada
| | - D Kozbor
- Department of Immunology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | - K Odunsi
- Center for Immunotherapy, Roswell Park Comprehensive Cancer Center, Roswell Park Cancer Institute, Elm and Carlton Sts, Buffalo, NY, 14263, USA.
- University of Chicago Comprehensive Cancer Center, 5841 South Maryland Avenue, MC1140, Chicago, IL, 60637, USA.
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Stephenson K, Womble MN, Elbin RJ. A-41 Exploring the Influence of Referral Source on State Anxiety Levels of Concussed Patients. Arch Clin Neuropsychol 2020. [DOI: 10.1093/arclin/acaa036.41] [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: 11/14/2022] Open
Abstract
Abstract
Objective
To explore the influence of referral source on state anxiety in concussed athletes.
Method
One hundred thirty athletes (mean age = 16.46, SD = 1.93 yrs; 42% female) seeking care for a concussion at a specialty clinic within 30 days of injury (M = 8.83, SD = 6.12 days) were enrolled in the study. Demographic (e.g., age, sex, and history of anxiety) and referral source (e.g., emergency department/urgent care, primary care/pediatrician, and athletic trainer) information were collected, and the State-Trait Anxiety Inventory (STAI) was administered to all participants. A one-way analysis of variance (ANOVA) was conducted to compare STAI scores between referral groups, and a logistic regression (LR) was used to assess the relationship between referral sources and patients with and without clinical levels of state anxiety (STAI > 40). Statistical significance for all analyses was (p < .05).
Results
Approximately 25% (32/130) of patients reported a history of anxiety, and 46% (60/130) scored above clinical cutoffs for clinical anxiety. The referral groups did not differ on STAI scores (F(3, 130) = 1.12, p = .34), and the LR was not significant, (χ2(2, N = 130) = 3.75, p = 0.15).
Conclusions
History of anxiety was highly correlated with state anxiety at the first clinical visit; however, patients referred from different medical sources did not differ on clinical levels of anxiety at the first clinical visit following concussion.
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Womble MN, Stephenson K, Gustman B, Castor E, Kontos AP, Schatz P, Elbin RJ. A-48 Athletes that self-report no physical activity/rest are more likely to exhibit clinical levels of state anxiety following concussion. Arch Clin Neuropsychol 2020. [DOI: 10.1093/arclin/acaa036.48] [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: 11/14/2022] Open
Abstract
Abstract
Objective
To investigate the influence of self-reported physical activity (PA) on state anxiety in athletes with concussion
Method
Participants were 230 athletes (mean age = 16.46, SD = 1.94; 43% female) seeking care for a concussion at a specialty clinic within 30 days of injury (M = 8.83, SD = 6.12 days). Demographic data were collected during the clinical interview: age, sex, and history of concussion, migraine, learning disability, attention deficit hyperactivity disorder, anxiety, and depression. Patients completed the State-Trait Anxiety Inventory (STAI) and self-reported current levels of PA; 113 participants reported rest or no physical activity (REST) and 117 reported at least minimal PA (ACTIVE). The groups were compared on demographic variables to ensure group equivalence. Independent samples t-test examined differences between groups on state anxiety scores and a chi-square with odds ratios (ORs) examined the relationship between PA groups and clinical levels of state anxiety (STAI > 40). Statistical significance for all analyses was (p < .05).
Results
The groups were similar on all demographic variables (p > .05). The NO PA/REST group exhibited significantly higher state anxiety scores at first clinic visit than the PA group (t (228) = 2.82, p = .005), and the NO PA/REST group was 2.26 times more likely to exhibit clinical levels of state anxiety than the PA group at first clinic visit (χ2 (1, N = 230) = 9.16, p = .002).
Conclusions
Anxiety that is secondary to concussive injury could be mitigated with physical activity. Healthcare providers should encourage individuals with concussion to engage in physical activity during recovery.
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Ayad T, Stephenson K, A L Smit D, Ben-Ari O, Késmárszky R, Lechien JR, Sobol S, Meller C, Sargi Z, Maunsell R, De Siati RD, Jia H, Krishnan V, North H, Eter EG, Metwaly O, Peer S, Teissier N, Sowerby L, Hong P, Fakhry N. Young Otolaryngologists of International Federation of Oto-rhino-laryngological Societies (YO-IFOS) committees. Eur Ann Otorhinolaryngol Head Neck Dis 2018; 135:S61-S65. [PMID: 30174261 DOI: 10.1016/j.anorl.2018.08.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/07/2018] [Accepted: 08/08/2018] [Indexed: 11/30/2022]
Affiliation(s)
- T Ayad
- Centre Hospitalier de l'Université de Montréal, Montreal, Canada.
| | - K Stephenson
- Birmingham Children's Hospital, Birmingham, United Kingdom
| | - D A L Smit
- University Medical Centre Utrecht, Utrecht, The Netherlands
| | - O Ben-Ari
- Tel Aviv Sourasky Medical Center, affiliated to Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - J R Lechien
- Centre Hospitalier Universitaire de Bruxelles, Site Saint-Pierre, Bruxelles, Belgium
| | - S Sobol
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
| | - C Meller
- Prince of Wales and Sydney Hospitals, Sydney, Australia
| | - Z Sargi
- Sylvester Comprehensive Cancer Center, University of Miami, Miami, Fl, USA
| | - R Maunsell
- Setor de Otorrinolaringologia Pediátrica, FCM-UNICAMP, Campinas, Brazil
| | - R D De Siati
- Université Catholique de Louvain, Cliniques Universitaires Saint Luc, Brussels, Belgium
| | - H Jia
- Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - V Krishnan
- Madras ENT Research Foundation, Raja Annamalaipuram, Chennai, India
| | - H North
- Westmead Hospital, Sydney, Australia
| | - E G Eter
- Saint joseph University, School of Medecine, Beirut, Lebanon
| | - O Metwaly
- Kasr Alainy School of Medicine, Cairo University, Cairo, Egypt
| | - S Peer
- Red Cross War Memorial Children's Hospital, Cape Town, South Africa
| | | | - L Sowerby
- St. Joseph's Healthcare, Western University, London, Canada
| | - P Hong
- IWK Health Centre, Division of Otolaryngology-Head and Neck Surgery, Dalhousie University, Halifax, Nova Scotia
| | - N Fakhry
- Hôpital de la Conception, Marseille, France
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Fournier I, Stephenson K, Fakhry N, Jia H, Sampathkumar R, Lechien JR, Melkane AE, Bahgat AY, De Carvalho Lopes K, Kennel T, Teissier N, Ayad T. Barriers to research among residents in Otolaryngology - Head & Neck Surgery around the world. Eur Ann Otorhinolaryngol Head Neck Dis 2018; 136:S3-S7. [PMID: 30143399 DOI: 10.1016/j.anorl.2018.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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: 05/07/2018] [Revised: 06/16/2018] [Accepted: 06/22/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To document the challenges faced by residents in Otolaryngology - Head & Neck Surgery (OTL-HNS) around the world to successfully complete research projects. The second objective is to assess if the challenges are uniform worldwide. METHODS A survey was sent to all OTL-HNS under 45 years old from the 2017 IFOS meeting. This survey was conducted by the YO-IFOS group (Young Otolaryngologists of the International Federation of Otolaryngological Societies). Data was collected for a period of 1 month. Demographic characteristics, information regarding research projects conducted and data concerning perceived barriers to completion of research projects were collected. RESULTS Among the 2787 attendees, 928 responded to the survey (response rate=33.3%). Of these 928 answers, 267 responses were from residents/interns in OTL-HNS, while 635 responses were from certified otolaryngologists. The three most frequent obstacles to conducting research projects for trainees were limited dedicated time (64%), insufficient financial resources (55%) and lack of education in research (45%). There was no statistical difference in these barriers among the different countries (P>0.05). CONCLUSION This is the first international study that provides insight on trainee's challenges to conduct research projects during residency. Despite the notion that research is essential for generating new knowledge to guide patient care, many residents fail to successfully incorporate research in their surgical curriculum. These obstacles must be addressed by Otolaryngology - Head & Neck Surgery programs in order to facilitate and support resident's research.
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Affiliation(s)
- I Fournier
- School of medecine, Université de Montréal, Montreal, Canada
| | - K Stephenson
- Birmingham Children's Hospital, Birmingham, United Kingdom
| | - N Fakhry
- Hôpital de la Conception, Marseille, France
| | - H Jia
- Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | | | - J R Lechien
- CHU de Bruxelles, site CHU Saint-Pierre, Brusells, Belgium
| | - A E Melkane
- Hotel-Dieu de France Hospital, Saint-Joseph University, Beirut, Lebanon
| | - A Y Bahgat
- Lecturer of Otorhinolaryngology and consultant of sleep Surgery, Alexandria University, Egypt
| | | | - T Kennel
- Université de Montpellier, hôpital universitaire Gui-de-Chauliac, CHRU de Montpellier, Montpellier, France
| | | | - T Ayad
- Centre hospitalier de l'université de Montréal, Montreal, Canada.
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11
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Lin SY, Lachowsky NJ, Hull M, Rich A, Cui Z, Sereda P, Jollimore J, Stephenson K, Thumath M, Montaner J, Roth EA, Hogg RS, Moore DM. Awareness and use of nonoccupational post-exposure prophylaxis among men who have sex with men in Vancouver, Canada. HIV Med 2016; 17:662-73. [PMID: 27477994 DOI: 10.1111/hiv.12369] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Nonoccupational post-exposure prophylaxis (nPEP) is a strategy to reduce the risk of HIV infection in those with high-risk exposure. This study characterized nPEP awareness among gay, bisexual and other men who have sex with men (MSM) in Metro Vancouver, British Columbia, Canada after a pilot nPEP programme established in 2012. METHODS Momentum Health Study participants were MSM aged ≥16 years recruited via respondent-driven sampling (RDS) who completed a computer-assisted self-interview. Stratifying patients by HIV status, we used multivariable logistic regression with backward selection to identify factors associated with nPEP awareness. All analyses were RDS-adjusted. RESULTS A total of 51.9% (112 of 173) of HIV-positive and 48.5% (272 of 500) of HIV-negative participants had heard of nPEP. Only 3% (five of 106) of HIV-negative participants who reported recent high-risk sex used nPEP. Generally, nPEP awareness was higher for participants who engaged in sexual activities with increased HIV transmission potential. Factors associated with greater awareness among HIV-negative participants included recent alcohol use, higher communal sexual altruism, previous sexually transmitted infection diagnosis, and greater perceived condom use self-efficacy. Other factors associated with greater awareness among HIV-negative participants included white race/ethnicity, gay sexual identity, more formal education, lower personal sexual altruism, and Vancouver residence. Greater nPEP awareness among HIV-positive participants was associated with greater perceived agency to ask sexual partners' HIV status and more frequently reporting doing so, a higher number of lifetime receptive sex partners, and greater access to condoms. CONCLUSIONS Following implementation of an nPEP pilot programme, nPEP awareness among HIV-negative MSM was 51% and use was 3%. These data support the need to expand access to and actively promote nPEP services.
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Affiliation(s)
- S Y Lin
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - N J Lachowsky
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.,Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - M Hull
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.,Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - A Rich
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - Z Cui
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - P Sereda
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
| | - J Jollimore
- Health Initiative for Men, Vancouver, BC, Canada
| | | | - M Thumath
- Faculty of Nursing, University of British Columbia, Vancouver, BC, Canada.,British Columbia Centre for Disease Control, Vancouver, BC, Canada
| | - Jsg Montaner
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.,Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - E A Roth
- Department of Anthropology, Faculty of Social Sciences, University of Victoria, Victoria, BC, Canada.,Centre for Addictions Research BC, Victoria, BC, Canada
| | - R S Hogg
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.,Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - D M Moore
- British Columbia Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada.,Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.,British Columbia Centre for Disease Control, Vancouver, BC, Canada
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Briggs S, Stephenson K, Holliday J, Peckham R, Arthur D, Papanikolaou M, Butt A, Pickford A, Pilkington G, Fillmore HL. O4.03 * GLIOBLASTOMA STIMULATED ANGIOGENESIS IS MEDIATED BY MMP-3 ACTIVATED MMP-1 VIA BRAIN ENDOTHELIAL CELL ASSOCIATED PROTEASE ACTIVATED RECEPTOR 1 (PAR1) AND IS ENHANCED UNDER HYPOXIC CONDITIONS. Neuro Oncol 2014. [DOI: 10.1093/neuonc/nou174.24] [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: 11/12/2022] Open
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13
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Cheng S, Stephenson K, Jain A, Horowitz D, Yan S, Wang T, Chao K, Hei T. The Effects of β-Adrenergic Antagonists on Radiation Therapy for Locally Advanced Lung Cancers. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.785] [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: 12/01/2022]
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14
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Barrable B, Thorogood N, Noonan V, Joshi P, Stephenson K, Kwon B, Dvorak M. P260 A Model For Bridging The Translational Valley Of Death In Spinal Cord Injury. BMJ Qual Saf 2013. [DOI: 10.1136/bmjqs-2013-002293.227] [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: 11/03/2022]
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15
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Franano F, Sifuentes X, Stephenson K, Brunell S, Ainsworth B. Blockstent deployment results in immediate vascular occlusion. J Vasc Interv Radiol 2013. [DOI: 10.1016/j.jvir.2013.01.424] [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: 10/27/2022] Open
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16
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Franano F, Sifuentes X, Stephenson K, Brunell S, Ainsworth B. Ballstent deployment results in immediate cerebral aneurysm occlusion. J Vasc Interv Radiol 2013. [DOI: 10.1016/j.jvir.2013.01.430] [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: 11/24/2022] Open
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17
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Sohl S, Stanbery K, Tooze J, Lentz S, Stephenson K, Danhauer S. P05.72. Survey to assess the feasibility of providing a brief yoga skills training to improve outcomes of gynecologic cancer surgery. BMC Complement Altern Med 2012. [PMCID: PMC3373772 DOI: 10.1186/1472-6882-12-s1-p432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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Stephenson K, Potter V. 6039 POSTER Pulmonary Metastatectomy for Colorectal Cancer – a Retrospective Review. Eur J Cancer 2011. [DOI: 10.1016/s0959-8049(11)71684-7] [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: 10/17/2022]
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19
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Ardalan B, Feagans M, Mezentsev D, Jones C, Subbarayan PR, Walker G, Sapp M, Stephenson K, Ness J, Franceschi D, Livingstone A. Phase II study of bevacizumab (B), camptosar (I), high-dose 24-hour continuous intravenous infusion of floxuridine (F) and leucovorin (L) in patients with previously untreated metastatic colon cancer. (B-IFL). J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e15114] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e15114 Background: In a previous study, IFL was used in patients (pt) with untreated metastatic colon cancer and a median overall survival (MOS) of 31 months (m). In the current study we added B to IFL to determine toxicity profiles (TP) and the response rate (RR) to the B-IFL regimen. The primary end-point is MOS Methods: Each cycle involved 6 weeks (wks) of treatment. The treatment cycle consisted of a 90 minute infusion of I (110 mg/m2), followed by a 24 hour infusion of F (120mg/kg) and L (500 mg/m2) on wks 1, 2, 4, 5. Pt received B (7.5mg/kg) over 90 minutes on wks 1 and 4 prior to IFL. No therapy was given on wks 3 and 6. Eligible pt received 2 cycles of B-IFL followed by CT scan. Quality of life data and thymidylate synthase expression in peripheral blood mononuclear cells was monitored Results: 22 pt with a median age of 57 (38–82), 11 males and 11 females were enrolled. Median KPS was 90% (50–100). 8 pt (36%) had bilobar liver disease and involvement of 1 other organ, 6 pt (27%) had bilobar liver disease with involvement of ≥ 2 other organs; 5 pt (23.5%) had bilobar liver disease; 2 pt (9%) had abdominal carcinomatosis; 1 pt (4.5 %) had involvement in one liver lobe. Grade (Gr) 4 toxicity: pulmonary embolus 1 pt (5%) incidental CT finding. Gr 3 occurred in 11 pt (50%); DVT, diarrhea (Drh) 3 pt (14%); fatigue (Ftg), infection, port site thrombosis (Pst), small bowel obstruction 2 pt (9%); wound dehiscence 1pt (5%); Gr 2 and 1: constipation; Drh; Ftg; nausea; neutropenia; Pst; alopecia; anorexia; mucositis. 17 pt remain alive with median follow up of 15 m (2–28). 5 pt have died due to progression of disease. The estimated median time to progression was 13 m with corresponding lower 95% confidence bound of 8.4 m. Kaplan-Meier estimate at 2 yr survival is 61% (95% CI 27–83%). RR in 21 pt was 67% (95% CI: 43–85%). Conclusions: B-IFL regimen has a manageable TP. RR and progression free interval were promising. Pt accrual is ongoing. Supported by Pfizer. No significant financial relationships to disclose.
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Affiliation(s)
| | | | | | | | | | | | - M. Sapp
- University of Miami, Miami, FL
| | | | - J. Ness
- University of Miami, Miami, FL
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20
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Stephenson K. S461 Two-component signal transduction systems of pathogenic bacteria as targets for anti-infective therapy. Int J Antimicrob Agents 2007. [DOI: 10.1016/s0924-8579(07)70307-2] [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: 10/23/2022]
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21
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Kavallaris M, Luduena R, Lu M, Prasaad V, Hammond L, Stephenson K, Arthaud L, Weitman S. 527 ILX651 inhibits polymerization of alpha beta III tubulin and is cytotoxic to beta tubulin mutant tumor cell lines that overexpress beta III tubulin. EJC Suppl 2004. [DOI: 10.1016/s1359-6349(04)80535-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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22
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Stephenson K, Hoch JA. Developing inhibitors to selectively target two-component and phosphorelay signal transduction systems of pathogenic microorganisms. Curr Med Chem 2004; 11:765-73. [PMID: 15032730 DOI: 10.2174/0929867043455765] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two-component signal transduction systems and their expanded variants known as phosphorelays are integral elements of the virulence and antimicrobial resistance responses of a wide range of pathogenic bacteria and fungi and also regulate essential functions. As a consequence, two-component systems and phosphorelays are recognized targets for the development of novel antimicrobial agents and a number of chemically synthesized inhibitors from different chemical classes have been identified by compound library screens. However, in the majority of cases these compounds do not appear to be selective for signal transduction pathways and exert their effect by multiple mechanisms of action. The key to designing molecules to selectively disrupt signal transduction may lie with the conserved features of response regulators and the structural analysis of complexes of signaling proteins.
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Affiliation(s)
- K Stephenson
- Department of Microbiology, School of Biochemistry and Biology, University of Leeds, Leeds, UK
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23
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Stephenson K, Hoch JA. Histidine kinase-mediated signal transduction systems of pathogenic microorganisms as targets for therapeutic intervention. Curr Drug Targets Infect Disord 2002; 2:235-46. [PMID: 12462127 DOI: 10.2174/1568005023342443] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pathogenic bacteria must be able to sense and respond rapidly to signals emanating from the host environment and use the signals to modulate the expression of genes required for the infection process. Two-component signal transduction systems, and their more complex variants known as phosphorelays, are woven within the fabric of bacterial cellular regulatory processes and are used to regulate the expression of genes involved in the virulence and antibiotic resistance responses of a large number of pathogens of major public health concern. The emergence of strains of pathogenic bacteria that are resistant to multiple antibiotics has driven the search for new targets and/or modes of action for anti-microbial agents. The presence of essential two-component systems in bacteria and the central role that these regulatory systems play in virulence and antibiotic resistance has meant that two-component systems and phosphorelays have been recognized as targets for antimicrobial intervention. This review will discuss the role of these signal transduction pathways in virulence responses and antibiotic sensitivity of pathogenic microorganisms and their potential use as targets for antimicrobial therapy. In addition, the current status on the development of inhibitors specific for two-component systems will be discussed.
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Affiliation(s)
- K Stephenson
- Division of Cellular Biology, Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
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24
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Stephenson K, Jensen CL, Jørgensen ST, Harwood CR. Simultaneous inactivation of the wprA and dltB genes of Bacillus subtilis reduces the yield of alpha-amylase. Lett Appl Microbiol 2002; 34:394-7. [PMID: 12028417 DOI: 10.1046/j.1472-765x.2002.01106.x] [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: 11/20/2022]
Abstract
AIMS In Gram-positive bacteria, signal peptide-bearing secretory proteins are translocated through the cytoplasmic membrane and fold into their native conformation on the outside of the cell. The products of the Bacillus subtilis wprA and dltB genes separately influence post-translocational stages of the secretion process by mediating proteolytic degradation and folding of secretory proteins. Inactivation of either wprA or dltB in B. subtilis increases the yield of secretory proteins released into the culture medium in an intact and biologically active conformation. The aim of this work was to study the combined influence of these genes. METHODS AND RESULTS A wprA/dltB double mutant was constructed, but did not have an additive effect on secretion and caused a significant reduction in the yield of alpha-amylase. CONCLUSIONS AND SIGNIFICANCE The activities of the wprA gene and the dlt operon interact in a negative way to influence the growth cycle and protein secretion. The mechanism by which this may occur, and its potential significance for the secretion of native and non-native proteins from B. subtilis and related bacteria, is discussed.
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Affiliation(s)
- K Stephenson
- Department of Microbiology and Immunology, The Medical School, Newcastle upon Tyne, UK
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25
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Stephenson K, Hoch JA. PAS-A domain of phosphorelay sensor kinase A: a catalytic ATP-binding domain involved in the initiation of development in Bacillus subtilis. Proc Natl Acad Sci U S A 2001; 98:15251-6. [PMID: 11734624 PMCID: PMC65015 DOI: 10.1073/pnas.251408398] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The major sensor kinase controlling the initiation of development in Bacillus subtilis, KinA, functions by activating the phosphorelay signal-transduction system in response to as yet unknown signal ligands. KinA contains, within its amino-terminal signal-sensing region, three PAS domains that, in other proteins, are known to be involved in sensing changes in oxygen concentration and redox potential among other functions. The most amino-terminal PAS domain, PAS-A, was found to bind ATP and catalyze exchange of phosphate between ATP and nucleoside diphosphates. A cysteine-to-alanine mutation in PAS-A increased the affinity for ATP 5-fold, decreased the exchange reaction 2-fold, and stimulated KinA-dependent sporulation. A model for the role of ATP and the exchange reaction in the PAS domain in sensor kinase signal transduction is presented in which the free energy of nucleotide hydrolysis drives the conformational changes that activate or deactivate the sensor kinase in response to signal ligand binding.
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Affiliation(s)
- K Stephenson
- Division of Cellular Biology, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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26
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Wang L, Fabret C, Kanamaru K, Stephenson K, Dartois V, Perego M, Hoch JA. Dissection of the functional and structural domains of phosphorelay histidine kinase A of Bacillus subtilis. J Bacteriol 2001; 183:2795-802. [PMID: 11292798 PMCID: PMC99495 DOI: 10.1128/jb.183.9.2795-2802.2001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The initiation of sporulation in Bacillus subtilis results primarily from phosphoryl group input into the phosphorelay by histidine kinases, the major kinase being kinase A. Kinase A is active as a homodimer, the protomer of which consists of an approximately 400-amino-acid N-terminal putative signal-sensing region and a 200-amino-acid C-terminal autokinase. On the basis of sequence similarity, the N-terminal region may be subdivided into three PAS domains: A, B, and C, located from the N- to the C-terminal end. Proteolysis experiments and two-hybrid analyses indicated that dimerization of the N-terminal region is accomplished through the PAS-B/PAS-C region of the molecule, whereas the most amino-proximal PAS-A domain is not dimerized. N-terminal deletions generated with maltose binding fusion proteins showed that an intact PAS-A domain is very important for enzymatic activity. Amino acid substitution mutations in PAS-A as well as PAS-C affected the in vivo activity of kinase A, suggesting that both PAS domains are required for signal sensing. The C-terminal autokinase, when produced without the N-terminal region, was a dimer, probably because of the dimerization required for formation of the four-helix-bundle phosphotransferase domain. The truncated autokinase was virtually inactive in autophosphorylation with ATP, whereas phosphorylation of the histidine of the phosphotransfer domain by back reactions from Spo0F~P appeared normal. The phosphorylated autokinase lost the ability to transfer its phosphoryl group to ADP, however. The N-terminal region appears to be essential both for signal sensing and for maintaining the correct conformation of the autokinase component domains.
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Affiliation(s)
- L Wang
- Division of Cellular Biology, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
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Abstract
Two-component signal transduction systems allow bacteria to sense and respond rapidly to changes in their environment leading to specific gene activation or repression. These two-component systems are integral in the ability of pathogenic bacteria to mount and establish a successful infection within the host and, consequently, have been recognized as targets for new anti-microbial agents. In this paper, we define the site and mechanism of action of several previously identified inhibitors of bacterial two-component systems. We show that the most potent inhibitors target the carboxyl-terminal catalytic domain of the sensor kinase and exert their affect by causing structural alterations of the kinase leading to aggregation. Recognition of this phenomenon has important implications for the development of novel inhibitors of two-component systems and should facilitate the rapid identification and elimination of compounds with nonspecific affects from medicinal chemistry drug discovery programs.
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Affiliation(s)
- K Stephenson
- Division of Cellular Biology, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
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Kastrati A, Koch W, Berger PB, Mehilli J, Stephenson K, Neumann FJ, von Beckerath N, Böttiger C, Duff GW, Schömig A. Protective role against restenosis from an interleukin-1 receptor antagonist gene polymorphism in patients treated with coronary stenting. J Am Coll Cardiol 2000; 36:2168-73. [PMID: 11127457 DOI: 10.1016/s0735-1097(00)01014-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To test the hypothesis that interleukin-1 receptor antagonist (IL-1ra) gene polymorphism contributes to the risk of restenosis after coronary stenting. BACKGROUND Cytokines of the interleukin-1 (IL-1) family play a central role in regulating inflammatory responses. There is strong evidence to support IL-1 involvement in smooth muscle cell mitogenesis and extracellular matrix metabolism. The IL-1ra counters the proinflammatory effects of IL-1. The interleukin-1 receptor antagonist gene (IL-1RN) contains several well-characterized polymorphic sites that correlate with altered IL-lra levels. METHODS In 1,850 consecutive patients, clinical and angiographic measures ofrestenosis were evaluated over one year after coronary stent placement. Repeat angiography at six months was achieved in 84% of the patients; angiographic restenosis was defined < or =50% diameter stenosis at follow-up. Genotyping for an exon 2 polymorphism (+2,018) of IL-1RN (alleles 1 and 2) was based on a polymerase chain reaction technique. RESULTS Allele 2 frequency was 0.28. Carriers of allele 2 had a significantly lower risk for angiographic restenosis, odds ratio (OR) of 0.78 (95% confidence interval, 0.63 to 0.97) and target vessel revascularization, OR of 0.73 (0.58 to 0.92) compared with noncarriers. Risk reduction was especially significant in patients <60 years (n = 696), with OR of 0.63 (0.43 to 0.91) for angiographic restenosis and 0.55 (0.39 to 0.78) for target vessel revascularization. CONCLUSIONS Allele 2 of the IL-1ra gene was associated with a lower incidence of restenosis after coronary stenting, particularly in younger patients. This finding supports a role of inflammation in the development of restenosis after stent placement.
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Affiliation(s)
- A Kastrati
- Deutsches Herzzentrum München and 1. Medizinische Klinik rechts der Isar, Technische Universität München, Munich, Germany.
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Hyyrylainen HL, Vitikainen M, Thwaite J, Wu H, Sarvas M, Harwood CR, Kontinen VP, Stephenson K. D-Alanine substitution of teichoic acids as a modulator of protein folding and stability at the cytoplasmic membrane/cell wall interface of Bacillus subtilis. J Biol Chem 2000; 275:26696-703. [PMID: 10871614 DOI: 10.1074/jbc.m003804200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [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: 11/06/2022] Open
Abstract
The extracytoplasmic folding of secreted proteins in Gram-positive bacteria is influenced by the microenvironment of the compartment into which they are translocated, namely the negatively charged matrix of the cell wall polymers. In this compartment, the PrsA lipoprotein facilitates correct post-translocational folding or prevents misfolding of secreted proteins. In this study, a secretion mutant of B. subtilis (prsA3) encoding a defective PrsA protein was mutagenized and screened for restored secretion of the AmyQ alpha-amylase. One mini-Tn10 insertion, which partially suppressed the secretion deficiency, was found to interrupt dlt, the operon involved in the d-alanylation of teichoic acids. The inactivation of dlt rescued the mutant PrsA3 protein from degradation, and the increased amount of PrsA3 was shown to enhance the secretion of PrsA-dependent proteins. Heterologous or abnormal secreted proteins, which are prone to degradation after translocation, were also stabilized and secreted in increased quantities from a dlt prsA(+) strain. Furthermore, the dlt mutation partially suppressed the lethal effect of PrsA depletion, suggesting that the dlt deficiency also leads to stabilization of an essential cell wall protein(s). Our results suggest that main influence of the increased net negative charge of the wall caused by the absence of d-alanine is to increase the rate of post-translocational folding of exported proteins.
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Affiliation(s)
- H L Hyyrylainen
- Vaccine Development Laboratory, National Public Health Institute, FI-00300 Helsinki, Finland
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30
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Stephenson K, Jensen CL, Jørgensen ST, Lakey JH, Harwood CR. The influence of secretory-protein charge on late stages of secretion from the Gram-positive bacterium Bacillus subtilis. Biochem J 2000; 350 Pt 1:31-9. [PMID: 10926823 PMCID: PMC1221221] [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: 02/17/2023]
Abstract
Following their secretion across the cytoplasmic membrane, processed secretory proteins of Bacillus subtilis must fold into their native conformation prior to translocation through the cell wall and release into the culture medium. The rate and efficiency of folding are critical in determining the yields of intact secretory proteins. The B. subtilis membrane is surrounded by a thick cell wall comprising a heteropolymeric matrix of peptidoglycan and anionic polymers. The latter confer a high density of negative charge on the wall, endowing it with ion-exchange properties, and secretory proteins destined for the culture medium must traverse the wall as the last stage in the export process. To determine the influence of charge on late stages in the secretion of proteins from this bacterium, we have used sequence data from two related alpha-amylases, to engineer the net charge of AmyL, an alpha-amylase from Bacillus licheniformis that is normally secreted efficiently from B. subtilis. While AmyL has a pI of 7.0, chimaeric enzymes with pI values of 5.0 and 10.0 were produced and characterized. Despite the engineered changes to their physico-chemical properties, the chimaeric enzymes retained many of the enzymic characteristics of AmyL. We show that the positively charged protein interacts with the cell wall in a manner that influences its secretion.
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Affiliation(s)
- K Stephenson
- Department of Microbiology and Immunology, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE24HH, U.K
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Bolhuis A, Tjalsma H, Stephenson K, Harwood CR, Venema G, Bron S, van Dijl JM. Different mechanisms for thermal inactivation of Bacillus subtilis signal peptidase mutants. J Biol Chem 1999; 274:15865-8. [PMID: 10336490 DOI: 10.1074/jbc.274.22.15865] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [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: 11/06/2022] Open
Abstract
The type I signal peptidase SipS of Bacillus subtilis is of major importance for the processing of secretory precursor proteins. In the present studies, we have investigated possible mechanisms of thermal inactivation of five temperature-sensitive SipS mutants. The results demonstrate that two of these mutants, L74A and Y81A, are structurally stable but strongly impaired in catalytic activity at 48 degrees C, showing the (unprecedented) involvement of the conserved leucine 74 and tyrosine 81 residues in the catalytic reaction of type I signal peptidases. This conclusion is supported by the crystal structure of the homologous signal peptidase of Escherichia coli (Paetzel, M., Dalbey, R. E., and Strynadka, N. C. J. (1998) Nature 396, 186-190). In contrast, the SipS mutant proteins R84A, R84H, and D146A were inactivated by proteolytic degradation, indicating that the conserved arginine 84 and aspartic acid 146 residues are required to obtain a protease-resistant conformation. The cell wall-bound protease WprA was shown to be involved in the degradation of SipS D146A, which is in accord with the fact that SipS has a large extracytoplasmic domain. As WprA was not involved in the degradation of the SipS mutant proteins R84A and R84H, we conclude that multiple proteases are responsible for the thermal inactivation of temperature-sensitive SipS mutants.
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Affiliation(s)
- A Bolhuis
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Kerklaan 30, 9751 NN Haren, The Netherlands
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Stephenson K. Open clinical trials for HIV/AIDS treatments. BETA 1998:56-8. [PMID: 11365994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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Abstract
AmyL, an extracellular alpha-amylase from Bacillus licheniformis, is resistant to extracellular proteases secreted by Bacillus subtilis during growth. Nevertheless, when AmyL is produced and secreted by B. subtilis, it is subject to considerable cell-associated proteolysis. Cell-wall-bound proteins CWBP52 and CWBP23 are the processed products of the B. subtilis wprA gene. Although no activity has been ascribed to CWBP23, CWBP52 exhibits serine protease activity. Using a strain encoding an inducible wprA gene, we show that a product of wprA, most likely CWBP52, is involved in the posttranslocational stability of AmyL. A construct in which wprA is not expressed exhibits an increased yield of alpha-amylase. The potential role of wprA in protein secretion is discussed, together with implications for the use of B. subtilis and related bacteria as hosts for the secretion of heterologous proteins.
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Affiliation(s)
- K Stephenson
- School of Microbiological, Immunological, and Virological Sciences, The Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, NE2 4HH, United Kingdom
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Stephenson K, Carter NM, Harwood CR, Petit-Glatron MF, Chambert R. The influence of protein folding on late stages of the secretion of alpha-amylases from Bacillus subtilis. FEBS Lett 1998; 430:385-9. [PMID: 9688576 DOI: 10.1016/s0014-5793(98)00698-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [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: 11/18/2022]
Abstract
A derivative of the alpha-amylase from Bacillus licheniformis (AmyL) engineered to give an active enzyme with increased net positive charge is secreted by Bacillus subtilis with a yield that is significantly lower than that of the native enzyme. This reduction in yield is the result of increased proteolysis during or shortly after translocation through the cytoplasmic membrane. When we compared the overall rate of folding of the engineered derivative (AmyLQS50.5) with that of AmyL it exhibited a greater dependency on Ca2+ ions for in vitro folding. When the concentration of Ca2+ in the growth medium was increased, so too did the relative yield of AmyLQS50.5. We discuss the importance of secretory protein folding at the membrane/cell wall interface with respect to the yield of native and heterologous proteins from B. subtilis.
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Affiliation(s)
- K Stephenson
- School of Microbiological, Immunological and Virological Sciences, The Medical School, University of Newcastle upon Tyne, UK
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36
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Stephenson K. Open clinical trials for HIV/AIDS treatments. BETA 1998:43-5, 54. [PMID: 11365564] [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] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Affiliation(s)
- K Stephenson
- San Francisco General Hospital, AIDS Program, San Francisco, CA
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37
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Stephenson K. Open clinical trials for HIV/AIDS treatments. BETA 1998:57-9. [PMID: 11365270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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38
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Gupta M, Stephenson K, Gauar S, Frenkel L. Intravenous pentamidine as an alternate for Pneumocystis carinii pneumonia prophylaxis in children with HIV infection. Pediatr Pulmonol Suppl 1998; 16:199-200. [PMID: 9443273] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- M Gupta
- Division of Pediatric Immunology, Allergy and Infectious Diseases, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, USA
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Balas EA, Boren SA, Hicks LL, Chonko AM, Stephenson K. Effect of linking practice data to published evidence. A randomized controlled trial of clinical direct reports. Med Care 1998; 36:79-87. [PMID: 9431333 DOI: 10.1097/00005650-199801000-00009] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES The purpose of this study was to evaluate the effect of clinical direct reports (practice data with pertinent evidence from the literature) on dialysis modality selection for patients with end-stage renal disease. METHODS A randomized controlled clinical trial was conducted at five dialysis centers. Five of the 10 physician participants were assigned through centralized computerized randomization to the intervention group (who received 12 center-specific clinical direct reports encouraging the consideration of peritoneal dialysis), and five were assigned to the control group, who received usual information but no similar report. One hundred fifty-two patients were eligible for monitoring. RESULTS The number of patients allocated to peritoneal dialysis was significantly higher in the intervention group than in the control group (15.3% versus 2.4%; P = 0.044). Due to a need for transient initial hemodialysis by some patients, the percentage of patients receiving peritoneal dialysis further increased through the end of the 3-month follow-up (18.0% versus 4.9%, P = 0.041). CONCLUSIONS There were no significant differences between the intervention and control groups in meeting patient preferences, metabolic status, and complication rates. The results of this study show that linking pertinent published evidence to actual practice data can support the implementation of practice recommendations and influence the selection of dialysis treatment for new patients.
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Affiliation(s)
- E A Balas
- Department of Health Management and Informatics, School of Medicine, University of Missouri, Columbia 65211, USA
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Stephenson K. Open clinical trials for HIV/AIDS treatments. BETA 1998:61-3. [PMID: 11364979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
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Abstract
Endothelin (ET) is a potent peptide mediator exhibiting a wide variety of effects in both the parenchymal and nonparenchymal hepatic cells. In the Kupffer cell, ET activates several transmembrane signaling pathways to generate numerous second messengers including the phospholipase C-generated products inositol-1,4,5-trisphosphate and diacylglycerol and the cyclooxygenase product prostaglandin E2 via specific ETB-type receptors. In addition to these findings, we have now demonstrated that endothelin stimulates the production of nitric oxide (NO) in the Kupffer cell in a time- and concentration-dependent manner. Western blot analysis indicates that ET-stimulated NO production occurs though activation of the inducible form of the nitric oxide synthase enzyme. These findings have important implications as the stimulation of NO production by ET may be part of the physiological response to inflammation or infection. Elevated levels of ET and NO have been found to be associated with numerous hepatic pathophysiological conditions that may contribute to derangements in the vascular system seen in these conditions.
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Affiliation(s)
- K Stephenson
- Department of Surgery, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78284, USA
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Delong R, Stephenson K, Loftus T, Fisher M, Alahari S, Nolting A, Juliano RL. Characterization of complexes of oligonucleotides with polyamidoamine starburst dendrimers and effects on intracellular delivery. J Pharm Sci 1997; 86:762-4. [PMID: 9188063 DOI: 10.1021/js960409f] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
This study evaluates polyamidoamine PAMAM "starburst" dendrimers (generation 3, Mr 6909) as a potential delivery vehicle for oligonucleotides. Complexes between dendrimer and phosphorothioate oligonucleotides were observed by agarose gel electrophoresis and were positive, negative, or neutral in charge depending on stoichiometry. Complexes were stable in 50% serum to variations in pH (3, 5, and 10) and ionic strength (0-500 mM). Ultrafiltration and gel filtration characterization indicated that the dendrimer:oligonucleotide complexes were primarily < 100 kD, although some larger complexes were formed at oligonucleotide excess. Use of dendrimers resulted in a 50-fold enhancement in cell uptake of oligonucleotide as determined by flow cytometry, and enhanced cytosolic and nuclear availability, as shown by confocal microscopy. These data support the further evaluation of dendrimers for oligonucleotide delivery in cell culture and in vivo.
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Affiliation(s)
- R Delong
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill 27599, USA
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Der-Karabetian A, Stephenson K, Poggi T. Environmental risk perception, activism and world-mindedness among samples of British and U.S. college students. Percept Mot Skills 1996; 83:541-62. [PMID: 9036372] [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: 02/03/2023]
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Stephenson K, Harvey SA, Mustafa SB, Eakes AT, Olson MS. Endothelin association with the cultured rat Kupffer cell: characterization and regulation. Hepatology 1995; 22:896-905. [PMID: 7657298] [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] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Circulating endothelin (ET) levels are elevated in conditions such as endotoxemia, hepatic ischemia-reperfusion injury, or orthotopic liver transplantation, and this potent peptide may contribute to hepatic pathophysiology. We measured the surface binding of [125I]ET-1 to rat Kupffer cells in primary culture at 4 degrees C; the dissociation constant (Kd) was 270 pmol/L, and the apparent Bmax was 3,000 receptors/cell. At 37 degrees C, total association (surface binding plus internalization) was much greater than at 4 degrees C, indicating that internalization of the receptor-ligand complex is rapid; the apparent Kd was 30 pmol/L, comparable with other reports for hepatic-derived cells. Studies using [125I]ET-1, [125I]ET-3, and specific ET (ant)agonists showed that Kupffer cells possess predominantly ET(B) type receptors. Prior treatment with 500 pmol/L unlabeled endothelin rapidly ( < 15 minutes) occluded 60% of subsequent [125I]ET association; using 5 nmol/L unlabeled ET, this occlusion occurred within 1 minute. [125I]ET association with Kupffer cells was unaffected by short-term (approximately 1 hour) treatment with cyclic adenosine monophosphate (cAMP), but long-term (20 hour) treatment resulted in a twofold increase in [125I]ET association with no change in the apparent Kd. Stimulation of protein kinase C in Kupffer cells by phorbol 12-myristate acetate had a dual regulatory effect on [125I]ET association. Short-term ( < 1 hour) treatment with phorbol 12-myristate acetate decreased [125I]ET-3 association by 50%, whereas prolonged treatment (20 hour) increased association twofold. In both cases, the apparent Kd for [125I]-endothelin was unaltered.
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Affiliation(s)
- K Stephenson
- Department of Biochemistry, University of Texas Health Science Center at San Antonio 78284-7842, USA
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Affiliation(s)
- K Stephenson
- Department of Biochemistry, University of Texas Health Science Center at San Antonio 78284
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Gandhi CR, Stephenson K, Olson MS. A comparative study of endothelin- and platelet-activating-factor-mediated signal transduction and prostaglandin synthesis in rat Kupffer cells. Biochem J 1992; 281 ( Pt 2):485-92. [PMID: 1310601 PMCID: PMC1130711 DOI: 10.1042/bj2810485] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Endothelin-3 (ET-3) stimulated phosphoinositide metabolism and synthesis of prostaglandins in cultured rat Kupffer cells. ET-3-induced hydrolysis of phosphoinositides was characterized by the production of various inositol phosphates and of glycerophosphoinositol. The mechanism of ET-3-stimulated metabolism of phosphoinositides and synthesis of prostaglandins appeared to be distinct from the effect of platelet-activating factor (PAF) on these processes described previously [Gandhi, Hanahan & Olson (1990) J. Biol. Chem. 265, 18234-18241]. On a molar basis ET-3 was significantly more potent than PAF in stimulating phosphoinositide metabolism, e.g. ET-3-induced hydrolysis of phosphoinositides occurred at 1 pM, whereas PAF was ineffective at concentrations less than 1 nM. Upon challenging Kupffer cells with both ET-3 and PAF, an additive stimulation of phosphoinositide metabolism was observed, suggesting that the actions of these factors may be exerted on separate phosphoinositide pools. Treatment of Kupffer cells with pertussis toxin resulted in an inhibition of ET-3-induced phospholipase C activation; in contrast, cholera toxin treatment caused potentiation of ET-3-stimulated phospholipase C activity. Both toxins, however, inhibited PAF-stimulated phospholipase C activity. The present results suggest that the stimulatory effects of ET-3 and PAF on the phosphodiesteric metabolism of phosphoinositides in Kupffer cells require different guanine-nucleotide-binding proteins. Furthermore, the effects of bacterial toxins on ET-3- and PAF-induced phosphoinositide metabolism were not mediated by cyclic AMP. ET-3-induced metabolism of phosphoinositides was inhibited completely in Kupffer cells pretreated with ET-3, suggesting homologous ligand-induced desensitization of the ET-3 receptors. In contrast, similar experiments using PAF showed only a partial desensitization of subsequent PAF-induced phosphoinositide metabolism. In contrast to the increased production of prostaglandins E2 and D2 observed upon stimulation of Kupffer cells with PAF, ET-3 stimulated the biosynthesis of prostaglandin E2 only. Consistent with their additive effects on phosphoinositide metabolism, PAF and ET-3 exhibited an additive stimulation of the synthesis of prostaglandin E2.
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Affiliation(s)
- C R Gandhi
- Department of Biochemistry, University of Texas, San Antonio 78284-7760
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Gandhi CR, Stephenson K, Olson MS. Endothelin, a potent peptide agonist in the liver. J Biol Chem 1990; 265:17432-5. [PMID: 2211635] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Endothelin, a peptide mediator produced by vascular endothelial cells, caused sustained vasoconstriction of the portal vasculature in the perfused rat liver. The vasoactive effect of endothelin was accompanied by increased glycogenolysis and alterations in hepatic oxygen consumption. The endothelin-induced increase in the portal pressure was concentration-dependent with an EC50 of 1 nM. Endothelin-induced hepatic glycogenolysis was dose-dependent but exhibited a different EC50 than for the vasoconstrictive effects of endothelin. Hepatic vasoconstriction and glycogenolysis following endothelin infusion were inhibited when Ca2+ was removed from the perfusion medium. The endothelin-induced responses in the liver were not altered by prior infusion of phenylephrine (alpha-adrenergic agonist), isoproterenol (beta-adrenergic agonist), angiotensin II, glucagon, platelet-activating factor, or the platelet-activating factor antagonist, BN52021. However, repeated infusion of endothelin resulted in desensitization of the glycogenolytic response but was without a significant effect on hepatic vasoconstriction. Endothelin also stimulated metabolism of inositol phospholipids in isolated hepatocytes and Kupffer cells in primary culture. The present experiments demonstrate, for the first time, that endothelin is a very potent agonist in the liver eliciting both a sustained vasoconstriction of the hepatic vasculature and a significant increase in hepatic glucose output.
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Affiliation(s)
- C R Gandhi
- Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284
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Wing EJ, Waheed A, Shadduck RK, Nagle LS, Stephenson K. Effect of colony stimulating factor on murine macrophages. Induction of antitumor activity. J Clin Invest 1982; 69:270-6. [PMID: 6799546 PMCID: PMC370975 DOI: 10.1172/jci110449] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Colony stimulating factor (CSF) was assessed for its capacity to stimulate antitumor activity in macrophages. Murine peritoneal macrophages incubated with CSF for 48 h inhibited [3H[thymidine (TdR) incorporation by P815 tumor cells to approximately 20% of control values. Inhibition of CSF-stimulated macrophages was significantly greater than inhibition by unstimulated macrophages (P less than 0.001). CSF had little direct effect on the proliferation of either tumor cells or macrophages alone, indicating that the antitumor activity of CSF was mediated by macrophages. it is unlikely that impurities in the CSF preparations were responsible for the effect since CSF that had been purified to homogeneity was as active as crude preparations. Furthermore the activity of CSF on macrophages was blocked by addition of purified anti-CSF antibodies. In addition to being tumoristatic, CSF-stimulated macrophages were tumoricidal as determined by a tumor colony growth assay. Tumor cells that had been incubated with CSF-stimulated macrophages showed a significant reduction in tumor colony-forming units (P less than 0.01). Thus, in addition to its effect on hemopoietic stem cells, CSF induces certain effector functions in mature macrophages that may enhance endogenous antitumor host defenses.
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