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Ilgen MA, Price AM, Coughlin LN, Pfeiffer PN, Stewart HJ, Pope E, Britton PC. Encouraging the use of the Veterans Crisis Line among high-risk Veterans: A randomized trial of a Crisis Line Facilitation intervention. J Psychiatr Res 2022; 154:159-166. [PMID: 35940001 DOI: 10.1016/j.jpsychires.2022.07.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/11/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022]
Abstract
The Veterans Crisis Line (VCL) is a core component of VA's suicide prevention strategy. Despite the availability and utility of the VCL, many Veterans do not utilize this resource during times of crisis. A brief, psychoeducational behavioral intervention (termed Crisis Line Facilitation [CLF]) was developed to increase utilization of the VCL and reduce suicidal behaviors in high-risk Veterans. The therapist-led session includes educational information regarding the VCL, as well as a chance to discuss the participant's perceptions of contacting the VCL during periods of crisis. The final component of the session is a practice call placed to the VCL by both the therapist and the participant. The CLF intervention was compared to Enhanced Usual Care (EUC) during a multi-site randomized clinical trial for 307 Veteran participants recently hospitalized for a suicidal crisis who reported no contact with the VCL in the prior 12 months. Initial analyses indicated that participants randomized to the CLF intervention were less likely to report suicidal behaviors, including suicide attempts compared to participants randomized to receive EUC over 12-months of follow-up (χ2 = 18.48/p < 0.0001), however this effect was not sustained when analyses were conducted on an individual level. No significant differences were found between conditions on VCL utilization. Initial evidence suggests a brief CLF intervention has an impact on preventing suicidal behaviors in Veterans treated in inpatient mental health programs; however, it may not change use of the VCL. This brief intervention could be easily adapted into clinical settings to be delivered by standard clinical staff.
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Affiliation(s)
- Mark A Ilgen
- VA Center for Clinical Management Research (CCMR), Department of Veterans Affairs Healthcare System, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Amanda M Price
- VA Center for Clinical Management Research (CCMR), Department of Veterans Affairs Healthcare System, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Lara N Coughlin
- VA Center for Clinical Management Research (CCMR), Department of Veterans Affairs Healthcare System, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Paul N Pfeiffer
- VA Center for Clinical Management Research (CCMR), Department of Veterans Affairs Healthcare System, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Haylie J Stewart
- VA Center for Clinical Management Research (CCMR), Department of Veterans Affairs Healthcare System, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Peter C Britton
- VA Center of Excellence for Suicide Prevention, VA Finger Lakes Health Care System, USA; Department of Psychiatry, University of Rochester Medical Center, Rochester, NY, USA
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Ilgen MA, Stewart HJ, Lhermitte SL, Pfeiffer PN, Britton PC, Pope EB. Developing and testing Crisis Line Facilitation (CLF) to encourage help-seeking in adults receiving inpatient treatment for a suicidal crisis. Cogn Behav Pract 2021; 28. [PMID: 33679121 DOI: 10.1016/j.cbpra.2020.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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] [Indexed: 11/18/2022]
Abstract
Military Veterans are at overall greater risk of suicide than non-Veterans and have experienced increases in rates of suicide that are on par with or exceed those of the general population. The Department of Veterans Affairs has undertaken several initiatives to reduce suicide among Veterans, including the development and expansion of the Veterans Crisis Line (VCL). The VCL has the potential to reduce suicidal behaviors, but it is likely underutilized by high-risk Veterans. This paper describes the development of Crisis Line Facilitation (CLF) a brief intervention, designed to increase use of the VCL in this high-risk population. In a single session, CLF presents psychoeducational information about the VCL, discusses the participant's perceived barriers and facilitators to future use of the VCL, and culminates in the Veteran calling the VCL with the therapist to provide firsthand experiences that may counter negative impressions of the line. The intervention development process, intervention and control condition, and self-reported change indices are presented. Preliminary results (N = 301) suggest Veterans receiving CLF may experience a significant increase in comfort with, and confidence in, using the VCL during future crises compared to those in the control condition.
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Affiliation(s)
- Mark A Ilgen
- VA Center for Clinical Management Research (CCMR)
- Department of Psychiatry, University of Michigan
| | - Haylie J Stewart
- VA Center for Clinical Management Research (CCMR)
- Department of Psychiatry, University of Michigan
| | | | - Paul N Pfeiffer
- VA Center for Clinical Management Research (CCMR)
- Department of Psychiatry, University of Michigan
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McKee MM, Meade MA, Zazove P, Stewart HJ, Jannausch ML, Ilgen MA. The Relationship Between Hearing Loss and Substance Use Disorders Among Adults in the U.S. Am J Prev Med 2019; 56:586-590. [PMID: 30772153 DOI: 10.1016/j.amepre.2018.10.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/28/2018] [Accepted: 10/29/2018] [Indexed: 11/24/2022]
Abstract
INTRODUCTION Hearing loss is common and associated with poorer health and impeded communication. Little is known about the association between hearing loss and substance use disorders in the general population. The objective of this study was to assess substance use disorder prevalence among individuals with hearing loss, versus those without hearing loss, in a nationally representative sample of adults. METHODS Two years (2015 and 2016) of National Survey on Drug Use and Health (unweighted N=86,186) were combined to compare substance use disorders among adults with and without self-reported hearing loss. Statistical analysis included descriptive frequencies, chi-square tests, and multiple logistic regressions. Analyses were performed in 2018. RESULTS Hearing loss prevalence across all age groups was 5.2%. Among younger age groups, after adjusting for sociodemographics, hearing loss was independently associated with an increased likelihood of experiencing a substance use disorder (ages 18-34 years, AOR=1.34, 95% CI=1.10, 1.64 vs 35-49 years, AOR=1.87, 95% CI=1.39, 2.53). Hearing loss was also associated with a greater likelihood of a prescription opioid use disorder (AOR=2.85, 95% CI=1.86, 4.39) in the group aged 18-34 years and, for the group aged 35-49 years, hearing loss increased the likelihood of both an alcohol use disorder (AOR=1.87, 95% CI=1.39, 2.53) and a prescription opioid use disorder (AOR=1.99, 95% CI=1.01, 3.91). CONCLUSIONS Hearing loss is independently associated with substance use disorders among those aged 49 years and younger; these associations are particularly pronounced for prescription opioid use disorders in the group aged 18-34 years. Given the concern of inappropriate use of prescription opioids, this information may have implications for healthcare providers' pain management for patients with hearing loss.
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Affiliation(s)
- Michael M McKee
- Department of Family Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
| | - Michelle A Meade
- Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, Michigan
| | - Philip Zazove
- Department of Family Medicine, University of Michigan Medical School, Ann Arbor, Michigan
| | - Haylie J Stewart
- VA Center for Clinical Management Research (CCMR), VA Ann Arbor Healthcare System, Ann Arbor, Michigan; Department of Psychiatry, University of Michigan, Ann Arbor, Michigan
| | - Mary L Jannausch
- VA Center for Clinical Management Research (CCMR), VA Ann Arbor Healthcare System, Ann Arbor, Michigan; Department of Psychiatry, University of Michigan, Ann Arbor, Michigan
| | - Mark A Ilgen
- VA Center for Clinical Management Research (CCMR), VA Ann Arbor Healthcare System, Ann Arbor, Michigan; Department of Psychiatry, University of Michigan, Ann Arbor, Michigan
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Forrest AP, Black RB, Humeniuk V, Cant EL, Hawkins RA, Prescott RJ, Roberts MM, Shivas AA, Stewart HJ, Smith AF, Sumerling M, Sumerling M. Preoperative Assessment and Staging of Breast Cancer: Preliminary Communication. J R Soc Med 2018; 73:561-6. [PMID: 7230232 PMCID: PMC1437852 DOI: 10.1177/014107688007300805] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A prospective study has been carried out in 172 women to determine the sensitivity of methods to detect occult metastatic disease in the skeleton and liver. With the exception of bone scintiscans, the results of these tests bore little relationship to recurrence rates. On the other hand, knowledge of the histopathology of the lower axillary (pectoral) lymph nodes is of value in this respect. A follow-up study is also reported which confirms the importance of accurate measurements of the primary tumour clinical node status and oestrogen receptor contact of the tumour in defining prognostic groups. Elastosis (estimated in 165 tumours) did not prove to be a useful prognostic index.
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Affiliation(s)
- A P M Forrest
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - F C Greenwood
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - H J Stewart
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - J P Thomas
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - R G Wood
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - W R G Thomas
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - A S Bligh
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
| | - G M Mitchell
- Welsh National School of Medicine, and United Cardiff Hospitals, Cardiff; Imperial Cancer Fund Research Laboratories, London
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Stewart HJ, Leroux-Carlucci MA, Sion CJM, Mitrophanous KA, Radcliffe PA. Development of inducible EIAV-based lentiviral vector packaging and producer cell lines. Gene Ther 2009; 16:805-14. [DOI: 10.1038/gt.2009.20] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Affiliation(s)
- H J Stewart
- Guggenheim Aeronautics Laboratory, California Institute of Technology
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Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York
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Stewart HJ, Cohn AE. STUDIES ON THE EFFECT OF THE ACTION OF DIGITALIS ON THE OUTPUT OF BLOOD FROM THE HEART: II. The Effect on the Output of the Hearts of Dogs Subject to Artificial Auricular Fibrillation. J Clin Invest 2006; 11:897-916. [PMID: 16694085 PMCID: PMC435857 DOI: 10.1172/jci100460] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York
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Stewart HJ, Deitrick JE, Crane NF, Thompson WP. STUDIES OF THE CIRCULATION IN THE PRESENCE OF ABNORMAL CARDIAC RHYTHMS. OBSERVATIONS RELATING TO (PART I) RHYTHMS ASSOCIATED WITH RAPID VEN-TRICULAR RATE AND TO (PART II) RHYTHMS ASSOCIATED WITH SLOW VENTRICULAR RATE. J Clin Invest 2006; 17:449-63. [PMID: 16694592 PMCID: PMC434801 DOI: 10.1172/jci100972] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Stewart HJ. THE EFFECT OF INCREASED HEART RATE DUE TO THE INJECTION OF ATROPINE ON THE OXYGEN SATURATION OF THE ARTERIAL AND VENOUS BLOOD OF PATIENTS WITH HEART DISEASE. J Clin Invest 2006; 3:241-51. [PMID: 16693712 PMCID: PMC434622 DOI: 10.1172/jci100077] [Citation(s) in RCA: 2] [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: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York, N. Y
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Cohn AE, Stewart HJ. THE RELATION BETWEEN CARDIAC SIZE AND CARDIAC OUTPUT PER MINUTE FOLLOWING THE ADMINISTRATION OF DIGITALIS IN NORMAL DOGS. J Clin Invest 2006; 6:53-77. [PMID: 16693821 PMCID: PMC434739 DOI: 10.1172/jci100188] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- A E Cohn
- Hospital of the Rockefeller Institute for Medical Research, New York
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Stewart HJ, Heuer GJ, Deitrick JE, Crane NF, Watson RF, Wheeler CH. MEASUREMENTS OF THE CIRCULATION IN CONSTRICTIVE PERICARDITIS BEFORE AND AFTER RESECTION OF THE PERICARDIUM. J Clin Invest 2006; 17:581-9. [PMID: 16694602 PMCID: PMC434812 DOI: 10.1172/jci100983] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Stewart HJ, Crawford JH, Hastings AB. THE EFFECT OF TACHYCARDIA ON THE BLOOD FLOW IN DOGS: I. The Effect of Rapid Irregular Rhythms as Seen in Auricular Fibrillation. J Clin Invest 2006; 3:435-47. [PMID: 16693725 PMCID: PMC434635 DOI: 10.1172/jci100090] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York, N. Y
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Stewart HJ, Gilchrist AR. STUDIES ON THE EFFECT OF CARDIAC IRREGULARITY ON THE CIRCULATION: II. The Estimation of Cardiac Output in Dogs Subject to Artificial Auricular Fibrillation. J Clin Invest 2006; 5:335-42. [PMID: 16693797 PMCID: PMC434715 DOI: 10.1172/jci100163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York
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Cohn AE, Stewart HJ. THE RELATION BETWEEN CARDIAC SIZE AND CARDIAC OUTPUT PER MINUTE FOLLOWING THE ADMINISTRATION OF DIGITALIS IN DOGS IN WHICH THE HEART IS ENLARGED. J Clin Invest 2006; 6:79-101. [PMID: 16693822 PMCID: PMC434740 DOI: 10.1172/jci100189] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- A E Cohn
- Hospital of The Rockefeller Institute for Medical Research, New York
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Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York, N. Y
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Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York, N. Y
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Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York, N. Y
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Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York, N. Y
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Stewart HJ. MECHANISM OF DIURESIS: ALTERATIONS IN THE SPECIFIC GRAVITY OF THE BLOOD PLASMA WITH ONSET OF DIURESIS IN HEART FAILURE. J Clin Invest 2006; 20:1-6. [PMID: 16694802 PMCID: PMC435025 DOI: 10.1172/jci101189] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Department of Medicine of the New York Hospital and Cornell University Medical College and the Hospital of the Rockefeller Institute for Medical Research, New York
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Stewart HJ, Bailey RL. THE CARDIAC OUTPUT AND OTHER MEASUREMENTS OF THE CIRCULATION IN COARCTATION OF THE AORTA. J Clin Invest 2006; 20:145-52. [PMID: 16694819 PMCID: PMC435042 DOI: 10.1172/jci101206] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Oppenheimer BS, Stewart HJ. DEPENDENCE OF THE FORM OF THE ELECTRO-CARDIOGRAM UPON THE SITE OF MECHANICAL STIMULATION OF THE HUMAN VENTRICLES. J Clin Invest 2006; 3:593-612. [PMID: 16693738 PMCID: PMC434648 DOI: 10.1172/jci100103] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- B S Oppenheimer
- Cardiographic Laboratory, Mt. Sinai Hospital and the Hospital of the Rockefeller Institute for Medical Research, New York
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Stewart HJ, Moore NS. THE NUMBER OF FORMED ELEMENTS IN THE URINARY SEDIMENT OF PATIENTS SUFFERING FROM HEART DISEASE, WITH PARTICULAR REFERENCE TO THE STATE OF HEART FAILURE. J Clin Invest 2006; 9:409-21. [PMID: 16693943 PMCID: PMC435706 DOI: 10.1172/jci100314] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York
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Moore NS, Stewart HJ. THE VARIATIONS OF THE SPECIFIC GRAVITY OF THE PLASMA OF THE BLOOD AND THE MEANS AVAILABLE FOR ALTERING IT. J Clin Invest 2006; 9:423-42. [PMID: 16693944 PMCID: PMC435707 DOI: 10.1172/jci100315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- N S Moore
- Hospital of The Rockefeller Institute for Medical Research, New York
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Affiliation(s)
- H J Stewart
- Department of Medicine of the New York Hospital and Cornell University Medical College, New York City
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Stewart HJ, McIntosh JF. THE FUNCTION OF THE KIDNEYS IN PATIENTS SUFFERING FROM CHRONIC CARDIAC DISEASE WITHOUT SIGNS OF HEART FAILURE. J Clin Invest 2006; 6:325-45. [PMID: 16693835 PMCID: PMC434757 DOI: 10.1172/jci100202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of The Rockefeller Institute for Medical Research, New York
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Stewart HJ, Cohn AE. STUDIES ON THE EFFECT OF THE ACTION OF DIGITALIS ON THE OUTPUT OF BLOOD FROM THE HEART. III. : Part 1. The Effect on the Output in Normal Human Hearts, Part 2. The Effect on the Output of Hearts in Heart Failure with Congestion, in Human Beings. J Clin Invest 2006; 11:917-55. [PMID: 16694086 PMCID: PMC435858 DOI: 10.1172/jci100461] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York
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Affiliation(s)
- A E Cohn
- Hospital of the Rockefeller Institute for Medical Research, New York, N.Y
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Stewart HJ, Crawford JH, Gilchrist AR. STUDIES ON THE EFFECT OF CARDIAC IRREGULARITY ON THE CIRCULATION: I. The Relation of Pulse Deficit to Rate of Blood Flow in Dogs Subject to Artificial Auricular Fibrillation and to Regular Tachycardia. J Clin Invest 2006; 5:317-33. [PMID: 16693796 PMCID: PMC434714 DOI: 10.1172/jci100162] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- H J Stewart
- Hospital of the Rockefeller Institute for Medical Research, New York City
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Mann SJ, Lamming GE, Fisher PA, Maeda S, Stewart HJ, Flint APF, Mann GE. Production of recombinant ovine interferon tau using a Bombyx mori nuclear polyhedrosis baculovirus expression system. Anim Biotechnol 2002; 13:149-58. [PMID: 12212938] [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: 02/26/2023]
Abstract
Ovine interferon tau (oIFN-tau) is an embryonic protein of critical importance in the establishment of pregnancy in the sheep. We have produced recombinant (r) oIFN-tau using a baculovirus expression system and demonstrated the biological activity of the protein produced. Bombyx mori larvae were infected with B. mori nuclear polyhedrosis virus (BmNPV), modified by inserting a cDNA coding for oIFN-tau downstream of the strong polyhedron promoter. Following infection, antiviral activity of the haemolymph rose to a maximum of 3.6 x 10(8) u/mL (equivalent to 3 mg roIFN-tau/mL) by day 5, when haemolymph was collected and stored frozen. Control haemolymph, collected from uninfected insects at an equivalent time, contained no antiviral activity. The roIFN-tau was partially purified by gel filtration column chromatography and the presence of roIFN-tau confirmed by western blotting. The biological activity of the partially purified roIFN-tau was tested in ewes. Treatment with roIFN-tau caused a significant delay in luteolysis confirming biological potency. The results demonstrate that this system can be successfully used to produce large quantities of roIFN-tau.
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Affiliation(s)
- S J Mann
- University of Nottingham, School of Biosciences, Division of Animal Physiology, Sutton Bonington, Loughborough, UK
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Mirsky R, Parkinson DB, Dong Z, Meier C, Calle E, Brennan A, Topilko P, Harris BS, Stewart HJ, Jessen KR. Regulation of genes involved in Schwann cell development and differentiation. Prog Brain Res 2001; 132:3-11. [PMID: 11544997 DOI: 10.1016/s0079-6123(01)32060-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- R Mirsky
- Department of Anatomy and Developmental Biology, University College London, Gower Street, WC1E 6BT London, UK.
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Stewart HJ, Brennan A, Rahman M, Zoidl G, Mitchell PJ, Jessen KR, Mirsky R. Developmental regulation and overexpression of the transcription factor AP-2, a potential regulator of the timing of Schwann cell generation. Eur J Neurosci 2001; 14:363-72. [PMID: 11553286 DOI: 10.1046/j.0953-816x.2001.01650.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [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
There is now evidence from in vivo and in vitro studies that the rate of Schwann cell generation is regulated by the balance of two opposing signals, beta neuregulins and endothelins. The beta neuregulins promote the development of precursors to Schwann cells whereas endothelins retard it through an action on endothelin-B receptors. The present work has shown additional controls of this transition, and implicates AP-2 transcription factors, in particular AP-2 alpha, as negative regulators of Schwann cell generation. We found that both AP-2 alpha and AP-2 gamma are present in early embryonic nerves, whereas AP-2 beta was not. Isoform-specific analysis of AP-2 alpha showed that isoform 3 was most abundant with isoforms 1 and 2 present in lesser amounts; isoform 4 was absent. Maximal AP-2 alpha and AP-2 gamma mRNA expression occurred at embryonic day (E) 12/13 in the mouse and at E14/15 in the rat, which correlates with the presence of Schwann cell precursors in the nerve. In both rats and in mice, in vivo and in vitro, downregulation of AP-2 alpha mRNA and protein coincided with one of the main steps in Schwann cell development, the precursor-Schwann cell transition. Moreover, Schwann cell generation was delayed if this downregulation was prevented by enforced expression of AP-2 alpha in precursors. These studies suggest that AP-2 is involved in the control of the timing of Schwann cell development.
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Affiliation(s)
- H J Stewart
- Trafford Centre for Medical Research, University of Sussex, Falmer, Brighton BN1 9RY, UK
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Abstract
BACKGROUND AND METHODS The Scottish Adjuvant Tamoxifen Trial (main trial) was initiated in April 1978 to assess the effect of tamoxifen given to patients with breast cancer immediately after mastectomy (or mastectomy plus radiation therapy) (adjuvant arm) or only after the patients had had a relapse (control arm); 1323 patients were randomly assigned (667 to the adjuvant arm and 656 to the control arm). Results have been reported for the follow-up period from 2.5 through 8 years. In this article, we report updated results after a median follow-up of 15 years. If agreeable and eligible, patients who were disease free at 5 years in the adjuvant arm of the main trial were entered into a duration trial and randomly assigned either to stop taking tamoxifen (169 patients) or to continue taking it indefinitely until relapse or death (173 patients). For this update, we analyzed information on death, recurrence, survival, and other malignancies for all but 21 of the 560 living patients from the original and duration trials to determine the probabilities of total survival, systemic relapse of disease, and death from breast cancer. All statistical tests are two-sided. RESULTS The beneficial effect of adjuvant tamoxifen given for 5 years on the probability of total survival (P =.006), systemic relapse (P =.007), and death from breast cancer (P =.002) has been maintained through 15 years. No additional benefit was observed in those randomly assigned to continue taking tamoxifen beyond 5 years. CONCLUSION Information from this study suggests that, if adjuvant tamoxifen is given to women with operable breast cancer, it need not be for more than 5 years.
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Affiliation(s)
- H J Stewart
- Scottish Cancer Trials Office, Edinburgh, Scotland, UK
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Abstract
Inherited retinal degenerations such as retinitis pigmentosa (RP) are characterized by progressive loss of photoreceptors, apparently by apoptosis, and our recent report of increased secreted Frizzled-related protein-2 (SFRP2) in RP retinas suggests altered Wnt signalling may be a component of the degenerative process. The present study shows that levels of SFRPI, SFRP3 and SFRP5 mRNAs are also abnormal in RP, giving rise to idiosyncratic expression patterns. In highly degenerative retinas, the SFRP proteins localize mainly to the inner limiting membrane, but in a well-preserved retina SFRPI and SFRP5 are notably localized to the surviving photoreceptors. Together with increased c-jun mRNA expression in all cases examined, these results support the notion that disruptions of Wnt network signalling are involved retinal neurodegeneration.
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Affiliation(s)
- S E Jones
- Division of Pharmacology and Therapeutics, The Rayne Institute, GKT, St Thomas' Hospital, London, UK
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Jones SE, Jomary C, Grist J, Stewart HJ, Neal MJ. Identification by array screening of altered nm23-M2/PuF mRNA expression in mouse retinal degeneration. Mol Cell Biol Res Commun 2000; 4:20-5. [PMID: 11152623 DOI: 10.1006/mcbr.2000.0250] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the rd/rd mouse model of inherited retinal degeneration, the majority of photoreceptors die apoptotically between postnatal age (P)10 and 20 days, during which period the inner retina appears morphologically unaffected. To examine mRNA changes associated with the degeneration, we performed differential screening of 588 arrayed murine cDNAs using probes reverse-transcribed from P8 predegenerative and control mouse retinal RNAs. We detected altered expression of the gene encoding nm23-M2, a member of the family of nucleoside diphosphate kinases implicated in diverse processes including metastasis suppression and transcriptional regulation. Retinal nm23 mRNA levels increased during degeneration while control levels decreased over age-matched time-points. In situ hybridization showed the high level of expression at P20 in rd/rd was concentrated in the retinal ganglion cells. Previous studies have indicated upregulation of the stress-response related gene alphaB-crystallin in the rd/rd inner retina, and increased nm23 levels may be a component of this response to photoreceptor loss and altered retinal architecture.
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Affiliation(s)
- S E Jones
- Retinitis Pigmentosa Research Unit, The Rayne Institute, London, SE1 7EH, United Kingdom
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Jones SE, Jomary C, Grist J, Stewart HJ, Neal MJ. Altered expression of secreted frizzled-related protein-2 in retinitis pigmentosa retinas. Invest Ophthalmol Vis Sci 2000; 41:1297-301. [PMID: 10798643] [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: 02/16/2023] Open
Abstract
PURPOSE Inherited retinal degenerations such as retinitis pigmentosa (RP) are characterized by progressive death of the photoreceptors due to apoptosis. To identify changes in gene expression associated with the degenerative state in RP retinas, expression profiling of apoptosis-related genes was performed using a gridded array technique. METHODS Total RNAs from RP and control retinas were used to generate radiolabeled cDNA probes to screen gridded membrane arrays of 205 apoptosis-related genes. Reverse transcription-polymerase chain reaction was used to generate probes corresponding to differentially expressed genes for Northern blot analysis and for mRNA in situ hybridization studies of retinal cryosections. Fluorescence immunocytochemistry was performed on retinal sections using available antibodies. RESULTS By expression profiling, we identified upregulated expression of the mRNA for secreted Frizzled-related protein-2 (SFRP2) in RP retina in comparison with control. By Northern blot analysis, SFRP2 mRNA levels were 2- to 20-fold higher in RP samples than in controls. The localization of SFRP2 mRNA by in situ hybridization varied according to the degree of degeneration, from stratified in relatively well-preserved retinas to diffuse in the highly degenerative state. By immunofluorescence, SFRP2 protein in RP retinas was found mainly to colocalize with the cell adhesion and signal transducing protein beta-catenin. CONCLUSIONS SFRPs can regulate apoptosis in vitro and appear to interact with the Wnt/Frizzled signaling pathway, which includes routes to apoptotic activation. Increased SFRP2 expression in RP retinas suggests that an altered pattern of Wnt signal transduction may be a step in the degenerative process linking causal mutations with eventual photoreceptor demise.
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Affiliation(s)
- S E Jones
- Department of Pharmacology, The Rayne Institute, GKT School of Biomedical Sciences, St Thomas' Hospital, London, UK.
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Tabernero A, Stewart HJ, Jessen KR, Mirsky R. The neuron-glia signal beta neuregulin induces sustained CREB phosphorylation on Ser-133 in cultured rat Schwann cells. Mol Cell Neurosci 1998; 10:309-22. [PMID: 9604209 DOI: 10.1006/mcne.1998.0662] [Citation(s) in RCA: 34] [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: 11/22/2022] Open
Abstract
beta neuregulins (also called NDF, GGF, ARIA, and heregulins) are neuron-derived molecules that are likely to be responsible for Schwann cell precursor survival, proliferation, and maturation in vivo and in vitro. Although the receptors to which beta neuregulins bind have been defined, little is known about the transcription factors these important ligands activate. Using antibodies, quantitative imaging methods and Western blotting, we show that beta neuregulin induces a high level of phosphorylation of the transcription factor cyclic AMP response element binding protein (CREB) on Ser-133 in cultured rat Schwann cells and that the phosphorylation is prolonged over several hours. In contrast, neurotrophins, CNTF, FGF-2, EGF, and TGF beta induce little or no phosphorylation of CREB despite the fact that receptors for these factors are present on Schwann cells. As expected CREB phosphorylation was detected following cAMP elevation, and it was also induced by elevation of cytoplasmic Ca2+, endothelin 1, and PDGF-BB. The signal was lower than that seen in response to beta neuregulin, and transient, unlike the sustained CREB activation induced by beta neuregulin. Our results suggest that the sustained phosphorylation of CREB on Ser-133 may contribute to the broad spectrum of effects that beta neuregulins have on cells of the Schwann cell lineage and that the CREB pathway may be important for transduction of neuregulin signals in Schwann cells.
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Affiliation(s)
- A Tabernero
- Department of Anatomy and Developmental Biology, University College London, England
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Stewart HJ, Zoidl G, Rossner M, Brennan A, Zoidl C, Nave KA, Mirsky R, Jessen KR. Helix-loop-helix proteins in Schwann cells: a study of regulation and subcellular localization of Ids, REB, and E12/47 during embryonic and postnatal development. J Neurosci Res 1998. [PMID: 9418957 DOI: 10.1002/(sici)1097-4547(19971201)50:5<684::aid-jnr6>3.0.co;2-d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although basic helix-loop-helix (bHLH) proteins play an important role in transcriptional control in many cell types, the role of HLH proteins in Schwann cells has yet to be assessed. In this study, we have analyzed the expression of the dominant negative HLH genes, Id1 to Id4 and the class A gene REB, during Schwann cell development. We found that mRNA derived from these genes was present in the Schwann cell lineage throughout development including embryonic precursors and mature cells. The mRNA levels were not significantly regulated during development. Nevertheless, by using antibodies against the four different Id proteins, we found clear regulation of some of these genes at the protein level, in particular Id 2, 4, and REB, both in amount and nuclear/cytoplasmic localization. All these proteins are found in the nuclei of Schwann cell precursors but are not seen in nuclei of Schwann cells of newborn nerves. We observed extensive overlap in Id expression, especially in Schwann cell precursors that co-expressed all four Id proteins and REB. We also showed that Id 1 and 2 were up-regulated as Schwann cells progressed through the cell cycle. These data indicate that HLH transcription factors act as regulators of Schwann cell development and point to the existence of as yet unidentified cell type-specific bHLH proteins in these cells.
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Affiliation(s)
- H J Stewart
- Department of Anatomy, University College London, United Kingdom.
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Stewart HJ, Zoidl G, Rossner M, Brennan A, Zoidl C, Nave KA, Mirsky R, Jessen KR. Helix-loop-helix proteins in Schwann cells: a study of regulation and subcellular localization of Ids, REB, and E12/47 during embryonic and postnatal development. J Neurosci Res 1997; 50:684-701. [PMID: 9418957 DOI: 10.1002/(sici)1097-4547(19971201)50:5<684::aid-jnr6>3.0.co;2-d] [Citation(s) in RCA: 41] [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: 02/05/2023]
Abstract
Although basic helix-loop-helix (bHLH) proteins play an important role in transcriptional control in many cell types, the role of HLH proteins in Schwann cells has yet to be assessed. In this study, we have analyzed the expression of the dominant negative HLH genes, Id1 to Id4 and the class A gene REB, during Schwann cell development. We found that mRNA derived from these genes was present in the Schwann cell lineage throughout development including embryonic precursors and mature cells. The mRNA levels were not significantly regulated during development. Nevertheless, by using antibodies against the four different Id proteins, we found clear regulation of some of these genes at the protein level, in particular Id 2, 4, and REB, both in amount and nuclear/cytoplasmic localization. All these proteins are found in the nuclei of Schwann cell precursors but are not seen in nuclei of Schwann cells of newborn nerves. We observed extensive overlap in Id expression, especially in Schwann cell precursors that co-expressed all four Id proteins and REB. We also showed that Id 1 and 2 were up-regulated as Schwann cells progressed through the cell cycle. These data indicate that HLH transcription factors act as regulators of Schwann cell development and point to the existence of as yet unidentified cell type-specific bHLH proteins in these cells.
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Affiliation(s)
- H J Stewart
- Department of Anatomy, University College London, United Kingdom.
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44
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Abstract
The interaction of cells with the extracellular matrix plays a critical role in morphogenesis and cell differentiation. To define how Schwann cells might interact with the extracellular matrix, we chose to study the expression of the laminin/collagen receptor alpha1beta1 integrin during nerve development in the rat from embryonic day 14 to maturity. We found that this integrin is expressed predominantly on mature non-myelin-forming cells and only at very low levels on myelin-forming cells. Significant levels of this integrin were not detected on Schwann cell precursors or embryonic Schwann cells in vivo. Experiments using transected and crushed sciatic nerve showed that alpha1beta1 integrin expression is regulated at least in part by axonal contact. Furthermore, Schwann cell culture experiments showed that alpha1beta1 integrin levels are strongly upregulated by transforming growth factor-beta(s) and phorbol esters.
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Affiliation(s)
- H J Stewart
- Department of Anatomy and Developmental Biology, University College, London, United Kingdom
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45
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Forrest AP, Stewart HJ, Everington D, Prescott RJ, McArdle CS, Harnett AN, Smith DC, George WD. Randomised controlled trial of conservation therapy for breast cancer: 6-year analysis of the Scottish trial. Scottish Cancer Trials Breast Group. Lancet 1996; 348:708-13. [PMID: 8806289 DOI: 10.1016/s0140-6736(96)02133-2] [Citation(s) in RCA: 282] [Impact Index Per Article: 10.1] [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: 02/02/2023]
Abstract
BACKGROUND To determine whether, when primary breast cancer is treated by local excision supported by systemic therapy appropriate to the oestrogen receptor status (ER) of the tumour, local radiotherapy can be avoided. METHODS We carried out a randomised controlled trial in 585 patients aged less than 70 years with primary breast cancers of 4 cm or less in size in four specialist units and seven other hospitals in Scotland. After local excision of the tumour (1 cm margin) and an axillary lymph-node clearance or sample, all patients received systemic therapy with oral tamoxifen 20 mg daily or six 3-weekly intravenous bolus injections of cyclophosphamide 600 mg, methotrexate 50 mg, and fluorouracil 600 mg per m2, depending upon the ER concentration in the primary tumour. Patients were then randomly allocated to postoperative radical radiotherapy (50 Gy to breast with boost to the tumour bed) or to no further local treatment. The median follow-up of living patients was 5.7 years. The primary analysis was by intention to treat but since some patients did not receive systemic therapy appropriate to their ER status, a subsidiary analysis was restricted to 464 patients in whom all details of the protocol had been observed. FINDINGS In the primary analysis survival was equal in the radiotherapy and non-radiotherapy groups (hazard ratio [HR] 0.98, 95% CI 0.67-1.44). Event-free survival showed an advantage in the irradiated patients (HR 0.54, 95% CI 0.39-0.74), largely due to fewer loco-regional relapses (HR 0.20, 95% CI 0.12-0.33). The relapse rate in the ipsilateral breast was 24.5% in the non-irradiated group and 5.8% following breast irradiation. The subsidiary analysis confirmed these findings and indicated the advantage of radiotherapy irrespective of ER concentration. There was a non-significant trend towards fewer distant metastases in the irradiated group. INTERPRETATION After local excision of a primary breast cancer, we conclude that radiotherapy to the residual breast tissue is advisable even when selective adjuvant systemic therapy is given.
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Affiliation(s)
- A P Forrest
- Scottish Cancer Trials Office, Medical School, University of Edinburgh, UK
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Stewart HJ, Forrest AP, Everington D, McDonald CC, Dewar JA, Hawkins RA, Prescott RJ, George WD. Randomised comparison of 5 years of adjuvant tamoxifen with continuous therapy for operable breast cancer. The Scottish Cancer Trials Breast Group. Br J Cancer 1996; 74:297-9. [PMID: 8688340 PMCID: PMC2074573 DOI: 10.1038/bjc.1996.356] [Citation(s) in RCA: 134] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In 1985 a second randomisation was initiated for women in the treatment arm of the Scottish Tamoxifen Trial either to stop tamoxifen at 5 years or to continue indefinitely. A preliminary analysis of outcome in 342 patients at a median follow-up of 6 years suggests that a worthwhile gain in disease control from continuing adjuvant tamoxifen beyond 5 years is unlikely. [Hazard ratio for events (relapse or death without relapse) is 1.27, 95% CI = 0.87 - 1.85.] There is a suggestion that therapy for longer than 5 years may increase the risk of endometrial carcinoma (P = 0.064).
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Affiliation(s)
- H J Stewart
- Scottish Cancer Trials Office, Medical School, University of Edinburgh, UK
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Riley PR, Abayasekara DR, Stewart HJ, Flint AP. Functional characterisation of an ovine endometrial oxytocin receptor cDNA transiently expressed in Cos-7 cells. J Endocrinol 1996; 149:389-96. [PMID: 8691097 DOI: 10.1677/joe.0.1490389] [Citation(s) in RCA: 5] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The entire coding region of an ovine endometrial oxytocin receptor (OTR) cDNA was generated by PCR, subcloned into the SV40 major late promoter expression vector pSVLJ and transiently expressed in Cos-7 cells. A specific OTR antagonist, 125I-labelled d(CH2)5 [Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin (OTA), was used to describe the binding kinetics of the expressed receptor which had a Kd of 4.5 nM and Bmax of 2.4 nM/mg protein (6.8 x 10(5) receptor molecules/transfected cell). The functional properties of the expressed OTR were determined by measuring oxytocin-induced phosphoinositide (PI) hydrolysis. Oxytocin increased PI turnover in OTR transfected cells fourfold in excess of residual endogenous activity, and stimulated phospholipase C (PLC) activity in a dose- and time-dependent manner, confirming that the expressed OTR cDNA was functional. Arginine vasopressin also stimulated PI turnover in a dose-dependent manner; thresholds of responses to oxytocin and arginine vasopressin were 10(-9) M and 10(-7) M respectively. OTA did not increase PI turnover and competitively inhibited the oxytocin-induced response. Direct activation of the pathway by aluminium fluoride and guanosine (3'-O-thio)-triphosphate (GTP gamma S) confirmed that the OTR was G-protein linked. Co-incubation of GTP gamma S with oxytocin shifted the PI-response threshold from 10(-7) M to 10(-9) M and significantly increased the level of response, suggesting that maximum PI turnover was agonist-dependent. The G-protein involved in mediating the signal transduction pathway was pertussis toxin-insensitive and, therefore, probably a member of the Gq subfamily. The PLC inhibitor, U73122, had no effect on oxytocin-induced PI turnover, consistent with the response in endometrial tissue. These data suggest that the signalling pathway mediated by expressed OTR is similar to that attributed to OTR occupancy in ovine endometrium.
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Affiliation(s)
- P R Riley
- Department of Physiology, Royal Free Hospital School of Medicine, London, UK
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Mirsky R, Stewart HJ, Tabernero A, Bradke F, Brennan A, Dong Z, Jessen KR. Development and differentiation of Schwann cells. Rev Neurol (Paris) 1996; 152:308-13. [PMID: 8881421] [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: 02/02/2023]
Abstract
Using the rat sciatic nerve as a model for the study of Schwann cell differentiation we have identified a Schwann cell precursor, a distinct cell type present in developing nerves at a time when they are projecting to their target tissues. These cells develop into Schwann cells over a relatively short time in vivo. In vitro, they can generate Schwann cells if they are cultured in neuron-conditioned medium or in the presence of neu-differentiation factors (NDF) (neuregulins, heregulins, glial growth factor), a recently discovered family of growth factors expressed at high levels in neurons. Thus neu-differentiation factors may be important neuro-glia signalling molecules in the Schwann cell lineage. Later stages in the development of Schann cells, such as differentiation towards a myelin phenotype, can be studied using cultured Schwann cells. These cells dedifferentiate both in vivo and in vitro when they are deprived of axonal contact. Elevation of intracellular cyclic AMP levels in the absence of cell division causes high levels of expression of Po, the major myelin glycoprotein. TGF beta s and FGFs suppress this induction, while IGFs promote it.
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Affiliation(s)
- R Mirsky
- Department of Anatomy and Developmental Biology, University College, London, England
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Abstract
A bovine trophoblast interferon (IFN-tau) gene promoter sequence (-450 to +26 bp relative to the transcription start site) led to expression of reporter gene (CAT) constructs transfected into L929 (murine fibroblast) or JAR (human choriocarcinoma) cells. Expression depended on the presence of an exogenous (SV40) enhancer. Poly(I)(C) activated endogenous IFN production in L929 and JAR cells but had no consistent effect on CAT expression. Similar results were obtained in L929 cells with inactivated Newcastle disease virus. There was no 'priming' effect of exogenous Type I IFN. Deletion mutants revealed sites exerting negative control on expression between - 338 and - 247 bp, and between - 150 and - 71 bp; these regions contained sequences resembling previously identified negative regulatory domains. In the absence of viral inducibility it is proposed that negative regulation contributes towards the stringent control of expression characteristic of IFN-tau genes.
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Stewart HJ, Bradke F, Tabernero A, Morrell D, Jessen KR, Mirsky R. Regulation of rat Schwann cell Po expression and DNA synthesis by insulin-like growth factors in vitro. Eur J Neurosci 1996; 8:553-64. [PMID: 8963447 DOI: 10.1111/j.1460-9568.1996.tb01240.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.0] [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: 02/03/2023]
Abstract
Myelination by Schwann cells is likely to be regulated in vivo by positive and negative epigenetic factors. In vitro, the positive regulation of myelin differentiation, in particular expression of the major myelin protein Po, can be mimicked by cAMP elevating agents, while serum, transforming growth factor (TGF) beta s, and fibroblast growth factor (FGF)2 have been shown to exert a negative effect on this differentiation. Growth factors which promote Po induction have not, however, been identified previously. Using a forskolin concentration (0.4 microM) which alone produces little Po mRNA or protein induction, we show that insulin-like growth factor (IGF)-I, IGF-II and high concentrations of insulin promote high levels of Po induction, although in the absence of forskolin they have no effect. Another event related to Schwann cell differentiation, induction of galactocerebroside expression in response to cAMP analogues, is also potentiated by IGFs. In a different context, IGFs regulate Schwann cell DNA synthesis. We find that in defined medium forskolin plus FGF2, TGF beta or platelet-derived growth factor (PDGF) BB causes minimal DNA synthesis in the absence of IGFs and that IGFs act as potent mitogens under these conditions. IGFs also potentiate DNA synthesis induced by beta isoforms of neu-differentiation factors (NDFs), although in this case considerable DNA synthesis occurs even in the absence of IGF. These results show that IGFs can act as powerful stimulators of both proliferation and differentiation in Schwann cells, and that the total growth factor input determines which of these pathways IGFs will promote.
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Affiliation(s)
- H J Stewart
- Department of Anatomy and Developmental Biology, University College London, UK
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