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Kochhar S, Izurieta HS, Chandler RE, Hacker A, Chen RT, Levitan B. Benefit-risk assessment of vaccines. Vaccine 2024; 42:969-971. [PMID: 37563049 DOI: 10.1016/j.vaccine.2023.07.041] [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] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 07/20/2023] [Indexed: 08/12/2023]
Abstract
Benefit-risk assessment (BRA) is critical for decision-making throughout the vaccine life cycle. It requires scientific assessment of evidence to make an informed judgment on whether the vaccine has a favourable benefit-risk profile i.e. the benefits of the vaccine outweigh its risks for use in its intended indication. The assessment must also consider data gaps and uncertainties, using sensitivity analyses to show the impact of these uncertainties in the assessment. The BRA field has advanced considerably over the past years, including the use of structured BRA frameworks, quantitative BRA models and use of the patient experience data. Analytical tools and procedures to standardize BRA implementation have become increasingly important. A Benefit-Risk Assessment Module has been prepared to enable the planning, assessment, and communication of relevant BRA information via a structured B-R framework. The module can help facilitate the conduct and communication of defensible BRAs by vaccine developers, funders, regulators and policy makers in high, middle or low-income countries, both for regulatory submissions and in public health responses to infectious diseases, including for epidemics.
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Affiliation(s)
- Sonali Kochhar
- University of Washington, Seattle, USA; Global Healthcare Consulting, India.
| | - Hector S Izurieta
- Center for Biologics Evaluation and Research, Food and Drug Administration, USA
| | | | - Adam Hacker
- Coalition of Epidemic Preparedness Innovations, London, UK
| | - Robert T Chen
- The Brighton Collaboration, Task Force for Global Health, Decatur, GA, USA
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2
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Halsey N, Evans S, Santosham M, Hacker A, Edwards KM, Chandler RE, Dudley MZ, Dekker CL, Al-Abri S, Arora N, Buttery J, Dodoo A, Eskola J, Heininger U, Jee Y, Khuri N, Obaro S, Orenstein W, Pitisuttithum P, Safadi M, Whitney CG, Black S. Considerations for unblinding individual study participants during vaccine trials. Vaccine 2023; 41:3399-3402. [PMID: 37121805 DOI: 10.1016/j.vaccine.2023.04.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 03/26/2023] [Accepted: 04/11/2023] [Indexed: 05/02/2023]
Abstract
Premature unblinding of individual participants is rarely reported in publications, but such unblinding can disrupt vaccine trials by causing worry and drop-out of other participants or "pseudo unblinding," in which participants or investigators over-interpret certain symptoms as being related to receiving an investigational product. This review summarizes appropriate reasons for unblinding in vaccine trials. Regulatory guidance could be improved by distinguishing guidance for vaccine trials from drug trials, with the recognition that unblinding individual participants in vaccine studies is rarely needed for management of adverse events following immunization.
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Affiliation(s)
- Neal Halsey
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States.
| | - Stephen Evans
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Mathuram Santosham
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Adam Hacker
- Coalition for Epidemic Preparedness Innovations, Norway
| | | | | | - Matthew Z Dudley
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | | | - Seif Al-Abri
- Directorate General for Disease Surveillance and Control, Muscat, Oman
| | - Narendra Arora
- Executive Director of The INCLEN Trust International, India
| | | | | | - Juhani Eskola
- National Institute for Health and Wellfare, Helsinki, Finland
| | | | | | | | - Stephen Obaro
- University of Nebraska Medical Center, United States
| | | | | | | | | | - Steve Black
- Global Vaccine Data Network, Auckland, New Zealand
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3
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Hacker A, Naifeh M. Do neonates with positive viral testing have a reduced risk of treatable infections? Am J Med Sci 2023. [DOI: 10.1016/s0002-9629(23)00518-9] [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: 01/28/2023]
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4
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Affiliation(s)
- Melanie Saville
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Jakob P Cramer
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Matthew Downham
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Adam Hacker
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Nicole Lurie
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Lieven Van der Veken
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Mike Whelan
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
| | - Richard Hatchett
- From the Coalition for Epidemic Preparedness Innovations, Oslo (M.S., J.P.C., M.D., A.H., N.L., M.W., R.H.), and McKinsey and Company, Geneva (L.V.V.)
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Krause PR, Arora N, Dowling W, Muñoz-Fontela C, Funnell S, Gaspar R, Gruber MF, Hacker A, Maria Henao-Restrepo A, Plotkin S, Rees HV, Smith DK, Swaminathan S. Making more COVID-19 vaccines available to address global needs: Considerations and a framework for their evaluation. Vaccine 2022; 40:5749-5751. [PMID: 35941036 PMCID: PMC9343170 DOI: 10.1016/j.vaccine.2022.07.028] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/21/2022] [Indexed: 10/28/2022]
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Finch CL, Martinez C, Leffel E, Skiadopoulos MH, Hacker A, Mwesigwa B, Maïga D, Mugisa I, Munkwase G, Rustomjee R. Vaccine Licensure in the Absence of Human Efficacy Data. Vaccines (Basel) 2022; 10:vaccines10030368. [PMID: 35335000 PMCID: PMC8954083 DOI: 10.3390/vaccines10030368] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/18/2022] [Accepted: 02/19/2022] [Indexed: 02/01/2023] Open
Abstract
Clinical vaccine development and regulatory approval generally occurs in a linear, sequential manner: Phase 1: safety, immunogenicity; Phase 2: immunogenicity, safety, dose ranging, and preliminary efficacy; Phase 3: definitive efficacy, safety, lot consistency; and following regulatory approval, Phase 4: post-marketing safety and effectiveness. For candidate filovirus vaccines, where correlates of protection have not been identified, and phase 2 and 3 efficacy of disease prevention trials untenable, large and/or protracted, each trial may span decades, with full licensure expected only after several decades of development. Given the urgent unmet need for new Marburg virus and Ebola Sudan virus vaccines, the Sabin Vaccine Institute hosted a key stakeholder virtual meeting in May 2021 to explore the possibility of licensure by use of an “animal rule-like” licensure process, based on a risk/benefit assessment specific to regional needs and informed by epidemiology. This may be appropriate for diseases where there are no or limited treatment options, and those prone to sporadic outbreaks with high rates of transmission, morbidity, and mortality. The discussion focused on two contexts: licensure within the Ugandan regulatory environment, a high burden country where Ebola vaccine trials are ongoing, and licensure by the United States FDA—a well-resourced regulatory agency.
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Affiliation(s)
- Courtney L. Finch
- Sabin Vaccine Institute, Washington, DC 20037, USA;
- Correspondence: (C.L.F.); (R.R.)
| | | | | | | | - Adam Hacker
- Coalition for Epidemic Preparedness Innovations, Bloomsbury, London NW1 2BE, UK;
| | - Betty Mwesigwa
- Makerere University Walter Reed Project, Kampala 16524, Uganda;
| | - Diadié Maïga
- Regional Office of Africa, World Health Organization, Brazzaville P.O. Box 06, Congo;
| | - Ian Mugisa
- National Drug Authority, Kampala 23096, Uganda; (I.M.); (G.M.)
| | - Grant Munkwase
- National Drug Authority, Kampala 23096, Uganda; (I.M.); (G.M.)
| | - Roxana Rustomjee
- Sabin Vaccine Institute, Washington, DC 20037, USA;
- Correspondence: (C.L.F.); (R.R.)
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Gómez Román R, Tornieporth N, Cherian NG, Shurtleff AC, L'Azou Jackson M, Yeskey D, Hacker A, Mungai E, Le TT. Medical countermeasures against henipaviruses: a review and public health perspective. Lancet Infect Dis 2021; 22:e13-e27. [PMID: 34735799 PMCID: PMC8694750 DOI: 10.1016/s1473-3099(21)00400-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 12/14/2022]
Abstract
Henipaviruses, including Nipah virus, are regarded as pathogens of notable epidemic potential because of their high pathogenicity and the paucity of specific medical countermeasures to control infections in humans. We review the evidence of medical countermeasures against henipaviruses and project their cost in a post-COVID-19 era. Given the sporadic and unpredictable nature of henipavirus outbreaks, innovative strategies will be needed to circumvent the infeasibility of traditional phase 3 clinical trial regulatory pathways. Stronger partnerships with scientific institutions and regulatory authorities in low-income and middle-income countries can inform coordination of appropriate investments and development of strategies and normative guidelines for the deployment and equitable use of multiple medical countermeasures. Accessible measures should include global, regional, and endemic in-country stockpiles of reasonably priced small molecules, monoclonal antibodies, and vaccines as part of a combined collection of products that could help to control henipavirus outbreaks and prevent future pandemics.
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Affiliation(s)
- Raúl Gómez Román
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Nadia Tornieporth
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway; University of Applied Sciences & Arts, Hanover, Germany
| | | | - Amy C Shurtleff
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | | | - Debra Yeskey
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Adam Hacker
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Eric Mungai
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway
| | - Tung Thanh Le
- Coalition for Epidemic Preparedness Innovations (CEPI), Oslo, Norway.
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8
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Vandeputte J, Saville M, Cavaleri M, Friede M, Hacker A, Mueller SO, Rizzi R, Smith D, Thirstrup S, Wagner R, Baay M, Neels P. IABS/CEPI platform technology webinar: Is it possible to reduce the vaccine development time? Biologicals 2021; 71:55-60. [PMID: 33966960 PMCID: PMC8102086 DOI: 10.1016/j.biologicals.2021.04.005] [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] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 11/19/2022] Open
Abstract
The International Alliance for Biological Standardization and the Coalition for Epidemic Preparedness Innovations organized a joint webinar on the use of platform technologies for vaccine development. To tackle new emerging infectious diseases, including SARS-CoV-2, rapid response platforms, using the same basic components as a backbone, yet adaptable for use against different pathogens by inserting new genetic or protein sequences, are essential. Furthermore, it is evident that development of platform technologies needs to continue, due to the emerging variants of SARS-CoV-2. The objective of the meeting was to discuss techniques for platform manufacturing that have been used for COVID-19 vaccine development, with input from regulatory authorities on their experiences with, and expectations of, the platforms. Industry and regulators have been very successful in cooperating, having completed the whole process from development to licensing at an unprecedented speed. However, we should learn from the experiences, to be able to be even faster when a next pandemic of disease X occurs.
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Affiliation(s)
- Joris Vandeputte
- International Alliance for Biological Standardization, IABS, Geneva, Switzerland.
| | - Melanie Saville
- Vaccine R&D, Coalition for Epidemic Preparedness Innovations, CEPI, London, United Kingdom.
| | - Marco Cavaleri
- EMA COVID-19 taskforce, European Medicines Agency, Amsterdam, the Netherlands
| | - Martin Friede
- Initiative for vaccine research, immunization and Vaccines, World Health Organization, Geneva, Switzerland
| | - Adam Hacker
- Global Regulatory Affairs, Coalition for Epidemic Preparedness Innovations, CEPI, London, United Kingdom
| | | | - Ruben Rizzi
- Global Regulatory Affairs, BioNTech, Germany
| | | | | | | | - Marc Baay
- P95 Epidemiology & Pharmacovigilance, Leuven, Belgium.
| | - Pieter Neels
- International Alliance for Biological Standardization, IABS, Geneva, Switzerland.
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9
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Turnbull IJ, Clarke R, Guo Y, Hacker A, Kartsonaki C, Bian Z, Sansome S, Chen H, Wu H, Xu X, Li L, Chen Z, Chen Y. P2780Accuracy of electronic healthcare records for diagnosis of stroke types in a large community-based prospective cohort study in China. Eur Heart J 2019. [DOI: 10.1093/eurheartj/ehz748.1096] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background and purpose
Reliable assessment of the determinants of major pathological types of stroke is dependent on the accuracy of diagnosis in population-based studies. We evaluated the diagnostic accuracy of stroke types in a large community-based cohort study involving health records collected in China.
Methods
In 2004–08, >0.5 million adults aged 30–79 years were recruited from general populations of 10 diverse areas (5 urban, 5 rural) in China. During an approximate 7-year follow-up, 37,694 stroke cases had been reported by linkage to electronic health records from disease-specific and mortality registries and from national health insurance agencies. For all reported stroke cases, hospital medical records were retrieved systematically and relevant data extracted for subsequent adjudication by specialists using bespoke electronic platforms.
Results
Among all reported incident stroke cases, 80% were ischaemic stroke (IS), 17% were intracerebral haemorrhage (ICH), and 1% were subarachnoid haemorrhage (SAH). To date, medical records have been retrieved for 29,632 cases, with reports of stroke diagnosis verified by public health staff in 27,115 (92%) cases, of which 3,778 (14%) were secondary diagnoses. Evidence of neuroimaging was found in 92% of all verified stroke cases. Of 23,337 primary stroke cases sent for specialist adjudication, a diagnosis of pathological stroke type was confirmed in 19,718 cases with the positive predictive values being 82.4% (95% confidence interval [CI], 82.0% - 82.8%) for IS, 97.8% (97.6 - 97.9) for ICH, and 98.2% (98.1 - 98.3) for SAH. Overall, the strength of association of systolic blood pressure was over 6-fold greater for confirmed than non-confirmed stroke cases and was nearly 3-fold greater for confirmed ICH than IS cases.
Diagnostic accuracy by stroke type Reported Retrieved Verified Adjudicated Confirmed Approximate 95% CI n n % n % n % n PPV, % IS 30,143 25,477 85 23,551 92 20,045 85 16,515 82.4 (82.0–82.8) ICH 6,484 3,486 54 3,079 88 2,919 95 2,854 97.8 (97.6–97.9) SAH 557 397 71 326 82 279 86 274 98.2 (98.1–98.3) Other 510 272 53 159 59 94 59 75 79.8 (79.4–80.2) IS indicates ischaemic stroke; ICH, intracerebral haemorrhage; SAH, subarachnoid haemorrhage; and PPV, positive predictive value.
Conclusions
The overall diagnostic accuracy of pathological stroke types obtained from hospital records in China is comparable to reports from Western populations. Despite advances in electronic healthcare records, reliable classification of stroke types requires clinical adjudication using additional relevant investigations.
Acknowledgement/Funding
Kadoorie Charitable Foundation, UK Wellcome Trust & National Natural Science Foundation and National Key Research and Development Program of China
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Affiliation(s)
- I J Turnbull
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
| | - R Clarke
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
| | - Y Guo
- Chinese Academy of Medical Sciences, Beijing, China
| | - A Hacker
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
| | - C Kartsonaki
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
| | - Z Bian
- Chinese Academy of Medical Sciences, Beijing, China
| | - S Sansome
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
| | - H Chen
- Center for Disease Control and Prevention, Non-Communicable Disease Prevention and Control Department, Huixian, China
| | - H Wu
- Center for Disease Control and Prevention, Non-Communicable Disease Prevention and Control Department, Huixian, China
| | - X Xu
- Center for Disease Control and Prevention, Liuyang, China
| | - L Li
- Chinese Academy of Medical Sciences, Beijing, China
| | - Z Chen
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
| | - Y Chen
- University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom
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Whelehan P, Heywang-Köbrunner S, Vinnicombe S, Hacker A, Jänsch A, Hapca A, Gray R, Jenkin M, Lowry K, Oeppen R, Reilly M, Stahnke M, Evans A. Clinical performance of Siemens digital breast tomosynthesis versus standard supplementary mammography for the assessment of screen-detected soft-tissue abnormalities: a multi-reader study. Clin Radiol 2017; 72:95.e9-95.e15. [DOI: 10.1016/j.crad.2016.08.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 08/18/2016] [Accepted: 08/31/2016] [Indexed: 11/25/2022]
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11
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Heywang-Koebrunner S, Bock K, Heindel W, Hecht G, Regitz-Jedermann L, Hacker A, Kaeaeb-Sanyal V. Mammography Screening - as of 2013. Geburtshilfe Frauenheilkd 2013; 73:1007-1016. [PMID: 24771889 DOI: 10.1055/s-0033-1350880] [Citation(s) in RCA: 8] [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: 05/16/2013] [Revised: 07/10/2013] [Accepted: 08/09/2013] [Indexed: 01/27/2023] Open
Abstract
Introduction: Since 2008 the German Mammography Screening Programme has been available throughout Germany to all women aged between 50 and 69. The programme strictly follows the European Guidelines. There are controversial discussions in the media as well as in the specialised press. Materials and Methods: Overview of the available data with regard to an evaluation of randomised studies and with regard to quality-assured screening programmes in accordance with EU Guidelines (including data from 18 screening countries). Results: Positive effects of screening: reduction in mortality, less invasive treatment. Negative effects: False-positive diagnoses and biopsy recommendations, so-called overdiagnoses, radiation dose. Limits of screening: Interval carcinomas, incomplete reduction in mortality. A mathematical synopsis of the latest publications from the European screening programmes with the diagnosis rates in Germany determined from > 4.6 million screening examinations produces the following: a total of 10 000 mammograms are created for 1000 women (P) taking part in the Mammography Screening Programme (each of whom undergoes 10 mammograms in 20 years). Overall, the risk of triggering breast cancer through a mammogram is very clearly below the annual natural risk of suffering from breast cancer. In the German screening, of these 1000 women, an average of 288 women are called back once in 20 years as a result of changes that are ultimately benign (< 3 % per cycle). Of these, 74 of the 288 women undergo a biopsy due to a benign change (false-positive biopsy recommendations, usually punch or vacuum biopsies). According to EUROSCREEN, 71 carcinomas develop among participants (56 are discovered in the screening, 15 in the interval), and 67 carcinomas among non-participants (N-P) (in some cases, several years later) during this period. The 4 additional diagnoses among the Ps are referred to as overdiagnoses, as they do not contribute to a reduction in mortality (these participants die beforehand from other causes of death). With regard to the carcinomas that concern the screening periods, 11 women out of 1000 die among the Ps; there are 19 deaths among the N-Ps (within the observation period plus follow-up period). Discussion: The false-positive rate is unavoidable, but is far lower with mammography screening than with other methods. Overdiagnoses are to be expected with any early detection. All calculations require assumptions and are therefore highly discrepant. They have very low evidence levels. The radiation dose should not be an argument against screening when applied correctly due to the very low risk and significant benefits. Interval carcinomas indicate the limits of a mammography screening programme. False-negatives only represent a subset of the interval carcinomas and are not to be equated with them. There is a very high evidence level for a significant reduction in mortality through mammography screening. For the first time, an independent expert commission has confirmed the results of the randomised studies and the statement of the WHO from 2002 and their further validity. Participants can expect a reduction in mortality of 30 %. Data from the current European screening programmes confirm a mortality reduction of 43 %, corresponding to 8/19 saved lives among 71 women with breast cancer or 1000 asymptomatic Ps. Many additional Ps benefit from less invasive treatment due to the early detection. Conclusions: As a result of the risk/benefit ratio, mammography screening should absolutely be recommended to asymptomatic women aged between 50-69. High importance is given to the provision of education for women by the treating gynaecologists as regards the opportunities for quality-assured early detection available to them in the healthcare system.
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Affiliation(s)
| | - K Bock
- Southwest Reference Centre, Marburg
| | | | - G Hecht
- North Reference Centre, Oldenburg
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12
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Keightley A, Hacker A. Metacarpal Titanium Elastic Nail insertion. Ann R Coll Surg Engl 2012. [PMID: 23031778 PMCID: PMC3954257 DOI: 10.1308/003588412x13373405387050c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- A Keightley
- Ashford and St Peter's Hospitals NHS Foundation Trust, UK.
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13
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Keightley A, Hacker A. Metacarpal Titanium Elastic Nail insertion. Ann R Coll Surg Engl 2012; 94:531-2. [DOI: 10.1308/rcsann.2012.531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- A Keightley
- Ashford and St Peter’s Hospitals NHS Foundation Trust, UK
| | - A Hacker
- Ashford and St Peter’s Hospitals NHS Foundation Trust, UK
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14
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Abstract
We evaluated the outcome of pyrocarbon arthroplasty for proximal interphalangeal joint osteoarthritis in 18 arthroplasties carried out by a single surgeon using the Ascension prosthesis (Ascension Orthopedics Inc., Austin, Texas) in 15 patients after a mean of 6.2 years. Significant and maintained improvements in pain scores at rest and on active movements were achieved for surviving implants, and the range of motion was comparable with preoperative measurements. The radiographs, which were evaluated for evidence of ongoing migration and potential failure, were of concern in 10 out of 18 joints. Two patients required implant removal.
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Affiliation(s)
- J R B Hutt
- Department of Trauma and Orthopaedic Surgery, Epsom and St. Helier NHS Trust, Carshalton, Surrey, UK.
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15
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Haupts MR, Meyer-Schwickerath R, Hacker A, Haug C, Fink F, Seidel D, Hartung HP. Normal CSF ferritin levels in MS suggest against etiologic role of chronic venous insufficiency. Neurology 2011; 76:2131-2132. [PMID: 21815295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023] Open
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16
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Heywang-Köbrunner S, Hacker A, Sedlacek S. Kontrastmittel-MRT der Brust bei Staging und Früherkennung: Wo benötigen wir sie? Geburtshilfe Frauenheilkd 2010. [DOI: 10.1055/s-0029-1240922] [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: 10/19/2022] Open
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17
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Heywang-Köbrunner S, Nährig J, Hacker A, Höfler H. 405 Evaluation of B3-lesions diagnosed at percutaneous biopsy and surgical results after excision. EJC Suppl 2010. [DOI: 10.1016/s1359-6349(10)70431-6] [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: 10/19/2022] Open
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18
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Chauhan S, Amir H, Chen G, Hacker A, Michel M, Koehrmann K. Intra-operative feedback and dynamic compensation for image-guided robotic focal ultrasound surgery. ACTA ACUST UNITED AC 2010; 13:353-68. [DOI: 10.3109/10929080802586825] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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19
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Heywang-Köbrunner SH, Nährig J, Hacker A. [Mammography screening. Concept, quality assurance and interdisciplinary cooperation]. Pathologe 2008; 29 Suppl 2:163-7. [PMID: 18807041 DOI: 10.1007/s00292-008-1024-0] [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] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In 2005/2006 the German National Mammography Screening Program was initiated and has now become established. The objective is to reduce breast cancer mortality and the early diagnosis and therapy of small cancers. The program follows the European guidelines and is controlled by over 30 parameters of quality. All trained members of the team document each step of the screening chain electronically. Histological assessment (HA) is recommended in up to 2% of examinations, 90% of HAs are performed by core needle biopsy (CNB) or by stereotactic vacuum-assisted biopsy (VABB). Open diagnostic biopsies are performed in <10% of all HAs and therapy is successful in some of the B3 lesions. Mammograms are interpreted by two independent readers. Recommendations of the regular interdisciplinary conferences, preoperative and postoperative, follow the European guidelines. About 45% of all breast cancers detected by screening are in-situ or less than 10 mm in size. The 17% alterations diagnosed by needle biopsy are B3 or B4 lesions and impose high demands on the pathologists and the interdisciplinary team. Due to the many early and discrete lesions counterchecking of representative biopsies is crucial. Problems may be caused by sampling error or partial volume effects. Interdisciplinary conferences and knowledge of the limitations of each discipline and method are needed to optimize diagnostic and therapeutic decisions.
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20
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Rider JE, Hacker A, Mackintosh CA, Pegg AE, Woster PM, Casero RA. Spermine and spermidine mediate protection against oxidative damage caused by hydrogen peroxide. Amino Acids 2007; 33:231-40. [PMID: 17396215 DOI: 10.1007/s00726-007-0513-4] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [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] [Received: 11/30/2006] [Accepted: 02/01/2007] [Indexed: 01/01/2023]
Abstract
The polyamines spermidine and spermine have been hypothesized to possess different functions in the protection of DNA from reactive oxygen species. The growth and survival of mouse fibroblasts unable to synthesize spermine were compared to their normal counterparts in their native and polyamine-depleted states in response to oxidative stress. The results of these studies suggest that when present at normal or supraphysiological concentrations, either spermidine or spermine can protect cells from reactive oxygen species. However, when polyamine pools are pharmacologically manipulated to produce cells with low levels of predominately spermine or spermidine, spermine appears to be more effective. Importantly, when cells are depleted of both glutathione and endogenous polyamines, they exhibit increased sensitivity to hydrogen peroxide as compared to glutathione depletion alone, suggesting that polyamines not only play a role in protecting cells from oxidative stress but this role is distinct from that played by glutathione.
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Affiliation(s)
- J E Rider
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
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21
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Fortin J, Marte W, Grüllenberger R, Hacker A, Habenbacher W, Heller A, Wagner C, Wach P, Skrabal F. Continuous non-invasive blood pressure monitoring using concentrically interlocking control loops. Comput Biol Med 2006; 36:941-57. [PMID: 16483562 DOI: 10.1016/j.compbiomed.2005.04.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 04/11/2005] [Accepted: 04/18/2005] [Indexed: 11/18/2022]
Abstract
A new method and apparatus for non-disruptive blood pressure (BP) recording in the finger based on the vascular unloading technique is introduced. The instrument, in contrast to intermittent set point readjustments of the conventional vascular unloading technique, delivers BP without interruptions, thus refining the Penáz' principle. The method is based on concentrically interlocking control loops for correct long-term tracing of finger BP, including automatic set point adaptation, light control and separate inlet and outlet valves for electro-pneumatic control. Examples of long-term BP recordings at rest and during autonomic function tests illustrate the potential of the new instrument.
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Affiliation(s)
- J Fortin
- Institute of Medical Engineering, Graz, University of Technology, Krenngasse, Graz, Austria.
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22
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Fortin J, Habenbacher W, Heller A, Hacker A, Grüllenberger R, Innerhofer J, Passath H, Wagner C, Haitchi G, Flotzinger D, Pacher R, Wach P. Non-invasive beat-to-beat cardiac output monitoring by an improved method of transthoracic bioimpedance measurement. Comput Biol Med 2005; 36:1185-203. [PMID: 16131462 DOI: 10.1016/j.compbiomed.2005.06.001] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 06/17/2005] [Accepted: 06/17/2005] [Indexed: 10/25/2022]
Abstract
The report describes a method of impedance cardiography using an improved estimate of thoracic volume. The formulas and their implementation in hardware and software are explained and new shortband electrodes are described which generate a good homogeneous thoracic field. Examples of stroke volume and cardiac output curves underline the capabilities of the monitoring system "Task Force Monitor". In several experiments, results are compared to thermodilution as well as to BioZ measurements: the new method excels in comparison with thermodilution and is comparable to the BioZ device. Compared to traditional electrodes, the new shortband electrodes are shown to provide better reproducibility.
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Affiliation(s)
- J Fortin
- Institute of Medical Engineering, Graz University of Technology, Krenngasse 37, A-8010 Graz, Austria.
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23
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Lecomte PV, Hacker A, Kojda G, De Hert SG. The negative inotropic effect of sevoflurane is not mediated through nitric oxide synthase in rat papillary muscle. Acta Anaesthesiol Belg 2003; 54:25-31. [PMID: 12703343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Sevoflurane has dose-dependent negative inotropic effects on myocardial contractility. The current study investigated whether the nitric oxide pathway is involved in these effects. A laboratory, ex-vivo experiment was performed on 66 isolated papillary muscles. Effects of increasing concentrations of sevoflurane (1, 2 and 3 MAC) were assessed in control conditions, in the presence of Nw-nitro-L-arginine (L-NOARG) and in beta-adrenergic stimulated rat papillary muscles. Contractility was assessed by total developed tension. In baseline conditions, the administration of increasing concentrations of sevoflurane caused a dose-dependent reduction in contractility of respectively 8.6 +/- 1.7%, 14.4 +/- 4.8% and 23.6 +/- 3.9%. This negative inotropic effect was not significantly altered by the administration of the NO-synthase inhibitor L-NOARG (p = 0.09). Under continuous administration of 3 MAC sevoflurane, 4 consecutive concentrations of isoproterenol induced a mean increase of contractility of respectively 43.0 +/- 13.7%, 65.9 +/- 22.6%, 131.2 +/- 25.6% and 122.3 +/- 31.2%. After administration of L-NOARG, the 4 consecutive concentrations of isoproterenol induced a mean increase in contractility of respectively 36.0 +/- 8.5%, 75.0 +/- 17.8%, 143.0 +/- 42.8% and 120.0 +/- 51.4% (p = 0.85). These data indicated that the negative inotropic effects of sevoflurane in rat papillary muscles, both in basic as in beta-adrenergic stimulated conditions, were not altered by blocking the NO-cGMP-system.
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Affiliation(s)
- P V Lecomte
- Department of Anesthesiology, University Hospital of Antwerp, Antwerp, Belgium
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24
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Casero RA, Wang Y, Stewart TM, Devereux W, Hacker A, Wang Y, Smith R, Woster PM. The role of polyamine catabolism in anti-tumour drug response. Biochem Soc Trans 2003; 31:361-5. [PMID: 12653639 DOI: 10.1042/bst0310361] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [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: 11/17/2022]
Abstract
Interest in polyamine catabolism has increased since it has been directly associated with the cytotoxic response of multiple tumour types to exposure to specific anti-tumour polyamine analogues. Human polyamine catabolism was considered to be a two-step pathway regulated by the rate-limiting enzyme spermidine/spermine N(1)-acetyltransferase (SSAT) that provides substrate for an acetylpolyamine oxidase (APAO). Further, the super-induction of SSAT by several anti-tumour polyamine analogues has been implicated in the cytotoxic response of specific solid-tumour phenotypes to these agents. This high induction of SSAT has been correlated with cellular response to the anti-tumour polyamine analogues in several systems and considerable progress has been made in understanding the molecular mechanisms that regulate the analogue-induced expression of SSAT. A polyamine response element has been identified and the transacting transcription factors that bind and stimulate transcription of SSAT have been cloned and characterized. The link between SSAT activity and cellular toxicity is thought to be based on the production of H(2)O(2) by the activity of the constitutive APAO that uses the SSAT-produced acetylated polyamines. The high induction of SSAT and the subsequent activity of APAO are linked to the cytotoxic response of some tumour cell types to specific polyamine analogues. However, we have recently cloned a variably spliced human polyamine oxidase (PAOh1) that is inducible by specific polyamine analogues, efficiently uses unacetylated spermine as a substrate, and also produces toxic H(2)O(2) as a product. The results of studies with PAOh1 suggest that it is an additional enzyme in polyamine catabolism that has the potential to significantly contribute to polyamine homoeostasis and drug response. Most importantly, PAOh1 is induced by specific polyamine analogues in a tumour-phenotype-specific manner in cell lines representative of the major forms of solid tumours, including lung, breast, colon and prostate. The sensitivity to these anti-tumour polyamine analogues can be significantly reduced if the tumour cells are co-treated with 250 microM of the polyamine oxidase inhibitor N (1), N (4)-bis(2,3-butadienyl)-1,4-butanediamine (MDL 72,527), suggesting that the H(2)O(2) produced by PAOh1 does in fact play a direct role in the observed cytotoxicity. These results strongly implicate PAOh1 as a new target that, in combination with SSAT, may be exploited for therapeutic advantage. The current understanding of the role and regulation of these two important polyamine catabolic enzymes are discussed.
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Affiliation(s)
- R A Casero
- Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, 1650 Orleans Street, Baltimore, MD 21231, U.S.A.
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Morawietz H, Weber M, Rueckschloss U, Lauer N, Hacker A, Kojda G. Upregulation of vascular NAD(P)H oxidase subunit gp91phox and impairment of the nitric oxide signal transduction pathway in hypertension. Biochem Biophys Res Commun 2001; 285:1130-5. [PMID: 11478771 DOI: 10.1006/bbrc.2001.5312] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [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]
Abstract
In this study we analyzed the role of vascular NAD(P)H oxidase in the generation of O(2)(-) and the endothelial impairment of NO signal transduction pathway in hypertension. In aortic rings of 15-month-old stroke-prone spontaneously hypertensive rats (SHR15) we found a 10-fold increased expression of NAD(P)H oxidase subunit gp91phox mRNA associated with a 3-fold increased production of O(2)(-) compared to age-matched Wistar rats (WIS15). Vasorelaxation studies in aortas of SHR15 showed a strongly diminished response to acetylcholine, NO-donor S-nitroso-N-acetyl-d,l-penicillamine, and organic nitrate glyceryl trinitrate compared to WIS15. Soluble guanylate cyclase (sGC) activity and sGC beta(1)-subunit protein expression was downregulated in aortas and lungs of SHR15. These data suggest an upregulation of vascular NAD(P)H oxidase and an impairment of the NO signal transduction pathway in hypertension.
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Affiliation(s)
- H Morawietz
- Institute of Pathophysiology, Martin Luther University Halle-Wittenberg, Halle, Germany
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26
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Wang Y, Devereux W, Woster PM, Stewart TM, Hacker A, Casero RA. Cloning and characterization of a human polyamine oxidase that is inducible by polyamine analogue exposure. Cancer Res 2001; 61:5370-3. [PMID: 11454677] [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: 02/20/2023]
Abstract
Mammalian polyamine catabolism is under the control of two enzymes, spermidine/spermine N1-acetyltransferase and the flavin adenine dinucleotide-dependent polyamine oxidase (PAO). In this study, the cloning and initial characterization of human PAO is reported. A 1894-bp cDNA with an open reading frame of 1668-bp codes for a protein of 555 amino acids. In vitro transcription/translation of this cDNA clone produces the expected M(r) 61,900 protein with PAO activity. The PAO activity of this clone is inhibited by MDL 72,527, a specific inhibitor of mammalian PAO. However, neither pargyline, a specific monoamine oxidase inhibitor, nor semicarbazide, a specific diamine oxidase inhibitor, inhibits the PAO activity of this clone. PAO has been referred to as being constitutively expressed. However, 24-h exposure of a non-small cell lung carcinoma cell line, NCI H157, to 10 microM of N1,N"-bis(ethyl)norspermine results in approximately 5-fold induction of PAO mRNA and a >3-fold induction of PAO activity. These results demonstrate that in at least one cell type, PAO is up-regulated in response to polyamine analogue exposure. The PAO clone described here should provide a useful tool, which will facilitate the dissection of the role of polyamine catabolism in normal growth and in response to the antitumor polyamine analogues.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Gene Expression Regulation, Enzymologic/drug effects
- Genes/genetics
- Humans
- Kinetics
- Molecular Sequence Data
- Oxidoreductases Acting on CH-NH Group Donors/genetics
- Oxidoreductases Acting on CH-NH Group Donors/metabolism
- Polyamines/chemistry
- Polyamines/pharmacology
- Protein Biosynthesis
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Analysis, DNA
- Transcription, Genetic
- Tumor Cells, Cultured
- Polyamine Oxidase
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Affiliation(s)
- Y Wang
- The Johns Hopkins Oncology Center, Bunting-Blaustein Cancer Research Building, Baltimore, Maryland 21231, USA
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27
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Abstract
The vertebrate nervous system performs the most complex functions of any organ system. This feat is mediated by dedicated assemblies of neurons that must be precisely connected to one another and to peripheral tissues during embryonic development. Motor neurons, which innervate muscle and regulate autonomic functions, form an integral part of this neural circuitry. The first part of this review describes the remarkable progress in our understanding of motor neuron differentiation, which is arguably the best understood model of neuronal differentiation to date. During development, the coordinate actions of inductive signals from adjacent non-neural tissues initiate the differentiation of distinct motor neuron subclasses, with specific projection patterns, at stereotypical locations within the neural tube. Underlying this specialisation is the expression of specific homeodomain proteins, which act combinatorially to confer motor neurons with both their generic and subtype-specific properties. Ensuring that specific motor neuron subtypes innervate the correct target structure, however, requires precise motor axon guidance mechanisms. The second half of this review focuses on how distinct motor neuron subtypes pursue highly specific projection patterns by responding differentially to spatially discrete attractive and repulsive molecular cues. The tight link between motor neuron specification and axon pathfinding appears to be established by the dominant role of homeodomain proteins in dictating the ways that navigating motor axons interpret the plethora of guidance cues impinging on growth cones.
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Affiliation(s)
- J Jacob
- MRC Centre for Developmental Neurobiology, King's College, London
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Caton A, Hacker A, Naeem A, Livet J, Maina F, Bladt F, Klein R, Birchmeier C, Guthrie S. The branchial arches and HGF are growth-promoting and chemoattractant for cranial motor axons. Development 2000; 127:1751-66. [PMID: 10725250 DOI: 10.1242/dev.127.8.1751] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [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
During development, cranial motor neurons extend their axons along distinct pathways into the periphery. For example, branchiomotor axons extend dorsally to leave the hindbrain via large dorsal exit points. They then grow in association with sensory ganglia, to their targets, the muscles of the branchial arches. We have investigated the possibility that pathway tissues might secrete diffusible chemorepellents or chemoattractants that guide cranial motor axons, using co-cultures in collagen gels. We found that explants of dorsal neural tube or hindbrain roof plate chemorepelled cranial motor axons, while explants of cranial sensory ganglia were weakly chemoattractive. Explants of branchial arch mesenchyme were strongly growth-promoting and chemoattractive for cranial motor axons. Enhanced and oriented axon outgrowth was also elicited by beads loaded with Hepatocyte Growth Factor (HGF); antibodies to this protein largely blocked the outgrowth and orientation effects of the branchial arch on motor axons. HGF was expressed in the branchial arches, whilst Met, which encodes an HGF receptor, was expressed by subpopulations of cranial motor neurons. Mice with targetted disruptions of HGF or Met showed defects in the navigation of hypoglossal motor axons into the branchial region. Branchial arch tissue may thus act as a target-derived factor that guides motor axons during development. This influence is likely to be mediated partly by Hepatocyte Growth Factor, although a component of branchial arch-mediated growth promotion and chemoattraction was not blocked by anti-HGF antibodies.
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Affiliation(s)
- A Caton
- Centre for Developmental Neurobiology, King's College, Guy's Campus, London SE1 9RT, UK
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29
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Abstract
Cells of the cranial paraxial mesoderm give rise to parts of the skull and muscles of the head. Some mesoderm cells migrate from locations close to the hindbrain into the branchial arches where they undergo muscle differentiation. We have characterised these migratory pathways in chick embryos either by DiI-labelling cells before migration or by grafting quail cranial paraxial mesoderm orthotopically. These experiments demonstrate that depending on their initial rostrocaudal position, cranial paraxial mesoderm cells migrate to fill the core of specific branchial arches. A survey of the expression of myogenic genes showed that the myogenic markers Myf5, MyoD and myogenin were expressed in branchial arch muscle, but at comparatively late stages compared with their expression in the somites. Pax3 was not expressed by myogenic cells that migrate into the branchial arches despite its expression in migrating precursors of limb muscles. In order to test whether segmental plate or somitic mesoderm has the ability to migrate in a cranial location, we grafted quail trunk mesoderm into the cranial paraxial mesoderm region. While segmental plate mesoderm cells did not migrate into the branchial arches, somitic cells were capable of migrating and were incorporated into the branchial arch muscle mass. Grafted somitic cells in the vicinity of the neural tube maintained expression of the somitic markers Pax3, MyoD and Pax1. By contrast, ectopic somitic cells located distal to the neural tube and in the branchial arches did not express Pax3. These data imply that signals in the vicinity of the hindbrain and branchial arches act on migrating myogenic cells to influence their gene expression and developmental pathways.
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Affiliation(s)
- A Hacker
- Department of Developmental Neurobiology, UMDS, Guy's Hospital, London, SE1 9RT, UK
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30
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Kojda G, Hacker A, Noack E. Effects of nonintermittent treatment of rabbits with pentaerythritol tetranitrate on vascular reactivity and superoxide production. Eur J Pharmacol 1998; 355:23-31. [PMID: 9754935 DOI: 10.1016/s0014-2999(98)00460-9] [Citation(s) in RCA: 40] [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: 02/08/2023]
Abstract
Pentaerythritol tetranitrate is an organic nitrate ester that undergoes metabolization to pentaerythritol, pentaerythritol trinitrate, pentaerythritol dinitrate and pentaerythritol mononitrate. Recent data suggested that pentaerythritol tetranitrate is endowed with vasoprotective activities in experimental atherosclerosis. This study was undertaken to gain insight into the underlying mechanism. The basic mechanism of action of all pentaerythritol nitrates was evaluated by measuring liberation of nitric oxide (NO), stimulation of human soluble guanylate cyclase and vasorelaxation in rabbit aorta. A subsequent in vivo study in New Zealand White rabbits was performed to investigate the effects of a 4 months lasting nonintermittent oral treatment with 6 mg pentaerythritol tetranitrate kg(-1) day(-1) on vascular superoxide production, endothelium dependent vasorelaxation and vasorelaxation to pentaerythritol tetranitrate itself. The formation rates of NO from the pentaerythritol nitrates (100 microM, n = 5) in presence of 5 mM cystein were (in nM min(-1)): 62.1 +/- 3.2 (pentaerythritol tetranitrate), 21.3 +/- 0.9 (pentaerythritol trinitrate), 6.4 +/- 0.6 (pentaerythritol dinitrate) and 3.2 +/- 0.4 (pentaerythritol mononitrate). Similarly, the pD2 values (-log M) for half-maximal activation of soluble guanylate cyclase decreased from pentaerythritol tetranitrate (3.391 +/- 0.09, n = 4) to pentaerythritol mononitrate (2.655 +/- 0.04, n = 3) as did the pD2 values (in -log M) for half-maximal relaxation of rabbit aortic rings (n = 7) from pentaerythritol tetranitrate (8.3 +/- 0.17) to pentaerythritol mononitrate (5.0 +/- 0.11). Significant correlations were found between the NO formation rates and the pD2 values for enzyme stimulation (r = 0.98, P = 0.002) and vasorelaxation (r = 0.90, P = 0.049) suggesting that these effects of the pentaerythritol nitrates were mediated by NO. The results of the in vivo study showed that aging induces a significant increase of aortic superoxide production (median values, n = 10) from 2.45 nM mg(-1) min(-1) (age 7 months) to 3.39 nM mg(-1) min(-1) (age 11 months, P < 0.01) that was prevented by concurrent treatment with pentaerythritol tetranitrate (2.76 nM mg(-1) min(-1)). In vitro vasorelaxation to pentaerythritol tetranitrate was identical in all groups indicating absence of nitrate tolerance. Endothelium-dependent vasorelaxation was also identical in all groups. These data suggest that oral treatment with pentaerythritol tetranitrate reduces vascular oxidant stress by an NO-dependent pathway, which may contribute to the vasoprotective activity of pentaerythritol tetranitrate in experimental atherosclerosis.
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Affiliation(s)
- G Kojda
- Institut für Pharmakologie, Heinrich-Heine-Universität, Düsseldorf, Germany.
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31
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Kojda G, Kottenberg K, Hacker A, Noack E. Alterations of the vascular and the myocardial guanylate cyclase/cGMP-system induced by long-term hypertension in rats. Pharm Acta Helv 1998; 73:27-35. [PMID: 9708036 DOI: 10.1016/s0031-6865(97)00044-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
NO as produced by NO-synthases (NOS) contributes to the regulation of cardiovascular functions. In hypertension, there is a reduced production and/or activity of endogenous NO in the vasculature. We investigated if hypertension alters the NO-sensitivity of soluble guanylate cyclase (sGC) in blood vessels and heart muscle isolated from 15 month old spontaneously hypertensive rats (SHR15) and normal Wistar rats (WIS). Inhibition of NOS by 1 mM N omega-nitro-L-arginine decreased dP/dtmax in WIS (-27.6 +/- 3.4%) and SHR15 (-26.0 +/- 4.4%), while stimulation of NOS with 1 mM L-arginine increased dP/dtmax in WIS (9.9 +/- 0.7%) and SHR15 (8.9 +/- 2.3%). The positive inotropic response to 0.1 microM glyceryl trinitrate (GTN) was comparable in WIS (dP/dtmax: 4.5 +/- 1.7%) and SHR15 (dP/dtmax: 3.75 +/- 0.7%) as was the positive inotropic response to the NO-donor sodium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolat (DEA/NO, 1 microM) in WIS (dP/dtmax: 10.7 +/- 2.9%) and SHR15 (dP/dtmax: 5.1 +/- 1.5%, P = 0.1873). In aortas of SHR15 we found an increased superoxide production of 19.4 +/- 1.7 nM/mg/min (WIS: 6.1 +/- 0.6 nM/mg/min) in the smooth muscle and the endothelial layer. Endothelium-dependent relaxation by acetylcholine was markedly impaired in SHR15 as was the vasorelaxant activity of S-nitroso-N-acetyl-D,L-penicillamine (SNAP), pentaerythritol tetranitrate and GTN. Maximal cGMP-production by sGC isolated from the lung and stimulated with SNAP (0.5 mM) was much lower in SHR15 (115 +/- 14 pmol/mg/min) than in WIS (348 +/- 36 pmol/mg/min). We suggest that hypertension is associated with a reduced activity of the sGC/cGMP-system in the vasculature but not in the heart muscle. Our results provide the first evidence that excess superoxide production in hypertension may trigger a desensitization of vascular sGC.
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Affiliation(s)
- G Kojda
- Institut für Pharmakologie, Heinrich-Heine-Universität, Dusseldorf, Germany.
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32
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Kojda G, Patzner M, Hacker A, Noack E. Nitric oxide inhibits vascular bioactivation of glyceryl trinitrate: a novel mechanism to explain preferential venodilation of organic nitrates. Mol Pharmacol 1998; 53:547-54. [PMID: 9495823 DOI: 10.1124/mol.53.3.547] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [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: 02/06/2023] Open
Abstract
Organic nitrates undergo enzymatic metabolization in the vasculature to release the active compound nitric oxide (NO). The resulting preferential venodilation has been suggested to be related to the vascular bioactivation process of organic nitrates because sodium nitroprusside, which is bioactivated differently, is not venoselective. We sought to determine whether NO has an influence on vascular bioconversion of organic nitrates because endogenous endothelial production of NO is smaller in veins than in arteries. Rings of porcine coronary arteries were subjected to radioactive glyceryl trinitrate (GTN) after preincubation with defined amounts of NO. The vascular content of GTN and the dinitrates (GDNs) 1,2-GDN and 1,3-GDN then was quantified. NO (3 microM, 30 min) significantly impaired bioactivation of GTN as indicated by a 30-50% reduction in the accumulation of 1,2-GDN and 1,3-GDN, whereas unchanged GTN was increased. Incubation with NO also reduced the stimulated specific activity of soluble guanylate cyclase isolated from human platelets. Its specific activity was reduced from 2.6 +/- 0.2 to 2.1 +/- 0.13 nmol of cGMP/mg/min. Relaxation studies with rings of porcine coronary arteries showed that NO-induced inhibition of vascular GTN metabolism and cGMP accumulation decreased the vasodilator potency of GTN by 10-fold. Further experiments showed that the duration of NO treatment is more important for this effect than the concentration of NO. We suggest that NO can inhibit vascular bioactivation of organic nitrates and might slightly desensitize soluble guanylate cyclase. The preferential venodilation induced by organic nitrates might be the result of the comparably low production of endogenous NO in veins.
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Affiliation(s)
- G Kojda
- Institut fur Pharmakologie, Medizinische Einrichtungen, Heinrich-Heine-Universitat, 40225 Dusseldorf, Germany.
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Kojda G, Hüsgen B, Hacker A, Perings D, Schnaith EM, Kottenberg E, Noack E. Impairment of endothelium-dependent vasorelaxation in experimental atherosclerosis is dependent on gender. Cardiovasc Res 1998; 37:738-47. [PMID: 9659458 DOI: 10.1016/s0008-6363(97)00268-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [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] Open
Abstract
OBJECTIVE Nitric oxide (NO) has been suggested to have antiatherosclerotic effects. It has also been demonstrated that there is a greater basal release of endothelium derived relaxing factor (EDRF) in female as compared to male rabbit aorta, which also might have beneficial effects in atherosclerosis. We thus sought to determine if gender influences the severity of atherosclerosis. METHODS We studied 18 female and 18 male New Zealand White rabbits that were randomly divided in two groups of 9 animals each and fed either a standard or a cholesterol diet (0.75%) for 15 weeks. RESULTS In cholesterol-fed rabbits the percentage of atherosclerotic lesions in the aorta was identical in females and males and was inversely correlated with the maximal aortic relaxation to acetylcholine as assessed in organ chamber experiments (females: P < 0.0008, males: P < 0.0002). Importantly, the cholesterol diet induced a significantly (P < 0.025) more severe impairment of maximal vasorelaxation to acetylcholine in males from 78.4 +/- 1.2% to 29.4 +/- 10.2%) compared to females (from 84.4 +/- 1.2% to 60.7 +/- 8.5%). Both male gender (P < 0.0001) and the extent of impairment of endothelium-dependent relaxation (P < 0.0002) were associated with a reduced aortic sensitivity to S-nitroso-N-acetyl-D,L-penicillamine, which releases NO into the organ bath. In contrast, the aortic sensitivity to the organic nitrates pentaerythritol tetranitrate and isosorbide 5-nitrate, which release NO after enzymatic metabolization within the smooth muscle, was not reduced. CONCLUSIONS These results suggest that the impairment of endothelium-dependent vasorelaxation induced by atherosclerosis is dependent on gender. This may be due to a greater degradation of extracellular NO in the vessel wall of males.
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Affiliation(s)
- G Kojda
- Institut für Pharmakologie, Heinrich-Heine-Universität, Düsseldorf, Germany
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34
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Affiliation(s)
- A Hacker
- Institute of Pharmaceutical Chemistry, Karl Franzens University of Gent, Austria
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35
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Abstract
The development of a precipitation flow injection immunoassay is described. This approach is based on the immunoprecipitin reaction, whereby the precipitate formed by binding of the sample antigen (HIgG) to fluorescein-labelled antibodies is retained on a filter built in on-line in a flow-injection system. After dissolving the precipitate with sodium hydroxide solution the liberation of fluorescein-labelled antibodies results in a fluorescence signal that is directly proportional to the concentration of HIgG. The instrumental set-up is very simple and fully automated. One assay cycle takes about 10 min. The RSD ranged between 1 and 3%, depending on concentration. The detection limit was about 140 fmol. The recovery from spiked serum samples was between 96 and 102%.
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Affiliation(s)
- A Hacker
- Institute of Pharmaceutical Chemistry, Karl-Franzens-University of Graz, Austria
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36
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Morais da Silva S, Hacker A, Harley V, Goodfellow P, Swain A, Lovell-Badge R. Sox9 expression during gonadal development implies a conserved role for the gene in testis differentiation in mammals and birds. Nat Genet 1996; 14:62-8. [PMID: 8782821 DOI: 10.1038/ng0996-62] [Citation(s) in RCA: 581] [Impact Index Per Article: 20.8] [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: 02/02/2023]
Abstract
Heterozygous mutations in SOX9 lead to a human dwarfism syndrome, Campomelic dysplasia. Consistent with a role in sex determination, we find that Sox9 expression closely follows differentiation of Sertoli cells in the mouse testis, in experimental sex reversal when fetal ovaries are grafted to adult kidneys and in the chick where there is no evidence for a Sry gene. Our results imply that Sox9 plays an essential role in sex determination, possibly immediately downstream of Sry in mammals, and that it functions as a critical Sertoli cell differentiation factor, perhaps in all vertebrates.
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Affiliation(s)
- S Morais da Silva
- Division of Developmental Genetics, MRC National Institute for Medical Research, Mill Hill, London, UK
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37
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Swain A, Zanaria E, Hacker A, Lovell-Badge R, Camerino G. Mouse Dax1 expression is consistent with a role in sex determination as well as in adrenal and hypothalamus function. Nat Genet 1996; 12:404-9. [PMID: 8630494 DOI: 10.1038/ng0496-404] [Citation(s) in RCA: 289] [Impact Index Per Article: 10.3] [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: 02/01/2023]
Abstract
Duplications of a chromosome Xp21 locus DSS (Dosage Sensitive Sex reversal) are associated with male to female sex reversal. An unusual member of the nuclear hormone receptor superfamily, DAX1, maps to the DSS critical region and is responsible for X-linked adrenal hypoplasia congenita. Here we describe the isolation of the mouse Dax1 gene and its pattern of expression during development. Expression was detected in the first stages of gonadal and adrenal differentiation and in the developing hypothalamus. Moreover, Dax1 expression is down-regulated coincident with overt differentiation in the testis, but persists in the developing ovary. Comparison of the predicted protein products of the human and mouse genes show that specific domains are evolving rapidly. Our results suggest a basis for adrenal insufficiency and hypogonadotropic hypogonadism in males affected by adrenal hypoplasia congenita and are consistent with a role for DAX1 in gonadal sex determination.
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Affiliation(s)
- A Swain
- Laboratory of Developmental Genetics, MRC National Institute for Medical Research, London, UK
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38
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Collignon J, Sockanathan S, Hacker A, Cohen-Tannoudji M, Norris D, Rastan S, Stevanovic M, Goodfellow PN, Lovell-Badge R. A comparison of the properties of Sox-3 with Sry and two related genes, Sox-1 and Sox-2. Development 1996; 122:509-20. [PMID: 8625802 DOI: 10.1242/dev.122.2.509] [Citation(s) in RCA: 337] [Impact Index Per Article: 12.0] [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: 11/20/2022]
Abstract
The Sox gene family consists of a large number of embryonically expressed genes related via the possession of a 79-amino-acid DNA-binding domain known as the HMG box. Partial clones for the first three Sox genes (al-a3) were isolated by homology to the HMG box of the testis-determining gene Sry and are now termed Sox-1, Sox-2 and Sox-3, Sox-3 is highly conserved amongst mammalian species and is located on the X chromosome. This has led to the proposal that Sry evolved from Sox-3. We present the cloning and sequencing of Sox-1, Sox-2 and Sox-3 from the mouse and show that Sox-3 is most closely relate to Sry. We also confirm that mouse Sox-3 is located on the X chromosome between Hprt and Dmd. Analysis of the distribution of Sox-3 RNA shows that its main site of expression is in the developing central nervous system, suggesting a role for Sox-3 in neural development. Moreover, we demonstrate that Sox-3, as well as Sox-1 and Sox-2, are expressed in the urogenital ridge and that their protein products are able to bind the same DNA sequence motif as Sry in vitro, but with different affinities. These observations prompt discussion of an evolutionary link between the genes and support the model that Sry has evolved from Sox-3. However our findings imply that if this is true, then Sry has undergone concomitant changes resulting in loss of CNS expression and altered DNA-binding properties.
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Affiliation(s)
- J Collignon
- Laboratory of Developmental Genetics, MRC National Institute for Medical Research, London, UK
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39
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Abstract
The process of sex determination, by which is meant the decision as to whether an embryo develops as a male or a female, is considered as a paradigm of how gene action can influence developmental fate. In mammals the decision is dependent on the action of the testis determining gene present on the Y chromosome, now known to be the gene Sry. Sry is expressed for only a brief period in the mouse embryo and must act to initiate rather than maintain the pathway of gene activity required for testis differentiation. It probably acts within cells of the supporting cell lineage to direct their differentiation into Sertoli cells, rather than the granulosa cells characteristic of the ovary. Other lineages in the gonad then follow the male pathway. The nature of the Sry transcript in the genital ridge of mice has been determined and compared with that from the human gene which is dramatically different. The expression of Sry has been carefully examined during the critical stages of genital ridge development and compared to the expression of a number of other genes involved in gonadal development and male development such as that for anti-Mullerian hormone. This has defined the period in which Sry must act to between 11 and 11.5 days post coitum. The expression of Sry has also been examined in cases of sex reversal in the mouse. There is a dependence on level of expression and extent of testicular differentiation that suggests thresholds for both the amount of SRY per cell and the number of cells expressing the gene. The SRY protein interacts with DNA through an HMG box type of DNA binding domain, however at present no definite target genes have been found. Progress on strategies to find such genes is discussed.
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Affiliation(s)
- R Lovell-Badge
- Division of Developmental Genetics, MRC National Institute for Medical Research, London, U.K
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40
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Dresser DW, Hacker A, Lovell-Badge R, Guerrier D. The genes for a spliceosome protein (SAP62) and the anti-Müllerian hormone (AMH) are contiguous. Hum Mol Genet 1995; 4:1613-8. [PMID: 8541848 DOI: 10.1093/hmg/4.9.1613] [Citation(s) in RCA: 39] [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: 01/31/2023] Open
Abstract
During an investigation of the regulatory potential of a region 5' of the mouse anti-müllerian hormone (Amh) gene, we identified a region of homology with the known cDNA sequence of a human spliceosome gene (SAP62). In mouse, the Sap62 termination codon (TGA) is just 434 bp 5' of the Amh start of translation (ATG); in the human the equivalent distance is 789 bp. RNase protection analysis shows the majority of Sap62 transcripts use an uncommon polyadenylation signal (ATTAAA) lying in the intragenic region, 87 bp 3' of the TGA. This analysis also shows that Sap62 is transcribed in all tissues examined, whereas specific Amh transcription initiating 10 bp 5' of the ATG is limited to the developing testis of the fetus from 11.5 days post coitum and in the ovary from 3 days post partum. However, in all tissues a significant number of Sap62 transcripts fail to polyadenylate in the intragenic region and continue through the Amh locus. This implies that the Amh locus is in an open chromatin state in all tissues despite a requirement for precise regulation. Human SAP62 can now be mapped to HSA19p and mouse Sap62 to MMU10.
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Affiliation(s)
- D W Dresser
- Laboratory of Cellular Immunology, National Institute for Medical Research, Mill Hill, London, UK
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41
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Abstract
In the mouse, Sry is expressed by germ cells in the adult testis and by somatic cells in the genital ridge. Transcripts in the former exist as circular RNA molecules of 1.23 kb, which are unlikely to be efficiently translated. We have used RNase protection to map the extent of the less abundant Sry transcript in the developing gonad. We demonstrate that it is a linear mRNA derived from a single exon. This begins in the unique region 5′ of the protein coding region and extends several kilobases into the 3′ arm of the large inverted repeat which bounds the Sry genomic locus. Knowledge of this transcript, which is very different from that of the human SRY gene, allows us to predict its protein product and reveals several features which may be involved in translational control. Our data is also consistent with there being two promoters for the Sry gene, a proximal one that gives functional transcripts in the genital ridge and a distal promoter used in germ cells in the adult testis. As RNase protection is a quantitative technique, a detailed timecourse of Sry expression was carried out using accurately staged samples. Sry transcripts are first detectable just after 10.5 days post coitum, they reach a peak at 11.5 days and then decline sharply so that none are detected 24 hours later. This was compared with anti-Mullerian hormone gene expression, an early marker of Sertoli cells and the first known downstream gene of Sry. Amh expression begins 20 hours after the onset of Sry expression at a time when Sry transcripts are at their peak. While this result does not prove a direct interaction between the two genes, it defines the critical period during which Sry must act to initiate Sertoli cell differentiation.
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Affiliation(s)
- A Hacker
- Laboratory of Developmental Genetics, Medical Research Council, National Institute for Medical Research, London, UK
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43
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Effros RM, Hacker A, Jacobs E, Audi S, Murphy C. Continuous measurements of changes in pulmonary capillary surface area with 201Tl infusions. J Appl Physiol (1985) 1994; 77:2093-103. [PMID: 7868421 DOI: 10.1152/jappl.1994.77.5.2093] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The impact of physiological and pathological processes on metabolism and transport of a variety of substances traversing the pulmonary vasculature depends in part on the capillary surface area available for exchange, and a reliable method for detecting changes in this parameter is needed. In this study, a continuous-infusion approach was used to investigate the response of the pulmonary capillary surface area to increases in flow and left atrial pressure. Isolated rat lungs were perfused with an acellular perfusion solution containing 125I-labeled albumin (an intravascular indicator) and 201Tl, a K+ analogue which is concentrated within lung cells. The extraction of 201Tl from the perfusate was 61% greater at low flow (8.5 ml/min) than at high flow (26 ml/min), and rapid changes in extraction were observed when flow was altered. In contrast, the permeability-surface area product was 76% greater when lungs were perfused at high flow than at low flow, suggesting comparable increases in pulmonary capillary surface area in these zone 2 lungs (airway pressure = 5 cmH2O, left atrial pressure < 0 cmH2O). In a second group of experiments, increases in left atrial pressure to 14 cmH2O (zone 3 lungs) at a constant flow of 8.5 ml/min increased the permeability-surface area product by only 18% despite increases in average intravascular pressure that were at least as high as those associated with high perfusion rates. 201Tl infusions provide a useful method for detecting and quantifying changes in pulmonary capillary surface area.
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Affiliation(s)
- R M Effros
- Department of Medicine, Medical College of Wisconsin, Milwaukee 53226
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44
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Abstract
The use of methylene blue (MB) to estimate dilution of epithelial lining fluid, which occurs during bronchoalveolar lavage (BAL), is complicated by loss of this redox dye from the air spaces. The rate of MB uptake from the air spaces of isolated rat lungs and the effects of oxidation and reduction on this process were investigated in this study. Movement of MB from the air spaces to perfusate was compared with the corresponding transport of 125I-labeled albumin, [14C]-dextran, 99mTc-labeled diethylenetriaminepentaacetate, [3H]-sucrose, and 3H2O. By the end of 2 min, MB concentrations in the BAL had fallen by 58 +/- 4% (SE; n = 11) and 3H2O by 78 +/- 2% (n = 13), whereas concentrations of the other indicators decreased by approximately 6%. All but 10% of the 3H2O lost from the air spaces was found in the perfusate, whereas 19% of the lost MB was not recovered in the perfusate, suggesting retention of MB in the pulmonary tissues. Absorption of MB from the air spaces was slowed by 20% when the lungs were left unperfused, and absorption was accelerated threefold by reduction of MB to leukomethylene blue with Na2S2O4. In contrast, MB losses from the air space were slowed by the oxidizing agent K3Fe(CN)6 and by addition of superoxide dismutase or ascorbic oxidase. It is therefore possible that ascorbic acid and O2- entering the air spaces reduce MB to the uncharged leuko form. Lowering the pH of the BAL fluid to 3.5 also slowed MB reabsorption. This suggests that acid aspiration may stimulate release of oxidants into the air spaces.
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Affiliation(s)
- R M Effros
- Department of Medicine, Medical College of Wisconsin, Milwaukee 53226
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45
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Capel B, Swain A, Nicolis S, Hacker A, Walter M, Koopman P, Goodfellow P, Lovell-Badge R. Circular transcripts of the testis-determining gene Sry in adult mouse testis. Cell 1993; 73:1019-30. [PMID: 7684656 DOI: 10.1016/0092-8674(93)90279-y] [Citation(s) in RCA: 830] [Impact Index Per Article: 26.8] [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: 01/26/2023]
Abstract
Sry is expressed at higher levels in the adult testis, where no function has been determined, than in the genital ridge, its critical site of action. cDNA and 5' RACE clones isolated from testis or from Sry-transfected cell lines have an unusual structure, with 3' sequences located in a 5' position. RNAase protection assays and reverse transcription polymerase chain reactions confirmed that these unusual RNA molecules represent the most abundant transcript in testis. Furthermore, oligonucleotide hybridization and RNAase H digestion proved that these Sry RNA molecules are circular. Similar transcripts were detected in the testes of mice with Mus musculus musculus, Mus musculus domesticus, and Mus spretus Sry genes. The circular RNA is found in the cytoplasm but is not substantially bound to polysomes. We suggest that the circles arise from normal splicing processes as a consequence of the unusual genomic structure surrounding the Sry locus in the mouse.
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Affiliation(s)
- B Capel
- Laboratory of Eukaryotic Molecular Genetics, Medical Research Council, National Institute for Medical Research, London, England
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46
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Abstract
Urea exchange is enhanced in renal collecting duct cells and erythrocytes by transporters which can be inhibited by phloretin and urea analogs such as thiourea. In this study, evidence for a comparable transporter was found in rat livers perfused with solutions which contained no red cells and in suspensions of hepatocytes. Bolus injections containing 125I-albumin (intravascular indicator), 99mTc-DTPA (extracellular indicator), 3HOH (water indicator), and [14C]urea were administered into the portal vein and fluid was collected from the hepatic vein. Under control conditions, [14C]urea and 3HOH emerged from the hepatic vein at nearly the same rate. However when the perfusate contained 2.5 mM phloretin (equivalent to 0.058 mM phloretin not bound to albumin), the amount of [14C]urea which had been recovered in the hepatic venous outflow by the time of peak 125I-albumin concentrations exceeded 3HOH recovery by a factor of 2.31 +/- 0.23 (n = 7). When the perfusate contained 200 mM thiourea, the comparable recovery of [14C]urea from the hepatic veins exceeded that of 3HOH by a factor of 3.48 +/- 0.44 (n = 7). These effects were at least partially reversible and suggested inhibition of urea transporters in hepatocytes. This conclusion was supported by studies of unloading of [14C]urea from hepatocytes which were exposed to unlabeled solutions: in the presence of phloretin, the amount of [14C]urea remaining within hepatocytes at 4 s was approximately twice that remaining in hepatocytes which had not been exposed to phloretin. Rapid transport of urea out of hepatocytes may increase urea synthesis and minimize cellular swelling due to urea accumulation.
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Affiliation(s)
- R M Effros
- Department of Medicine, Medical College of Wisconsin, Milwaukee 53226
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47
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Abstract
Urea has been used as an indicator for estimating 1) the dilution of epithelial lining fluid (ELF) that occurs during bronchoalveolar lavage (BAL) and 2) the permeability-surface area product (PS) of the pulmonary endothelium to this solute. Because relatively little is known about how urea equilibrates with fluid in the lung tissues and airspaces, we have undertaken a study of the kinetics of movement from the vasculature into the tissues of isolated, perfused rat lungs. Although instillation of 5 ml of 154 mM saline into the airspaces of this preparation increased the calculated extravascular volume of 3HOH from 0.64 +/- 0.23 to 2.10 +/- 0.58 ml (SE, n = 6) during a single transit through the pulmonary circulation, it did not have a detectable effect on the distribution of [14C]urea in the lung tissues. However, leakage of [14C]urea into saline within the airspaces was detected during constant infusions: concentrations in the airspace fluid reached 1.1 +/- 0.2% of those in the perfusate by 90 s and 1.90 +/- 0.2% at 120 s, levels that would significantly reduce estimates of the dilution of ELF by BAL. In contrast, concentrations of 99mTc-diethylenetriaminepentaacetic acetic acid (DTPA) in the airspaces remained < 0.2% of those in the perfusate, suggesting that 99mTc-DTPA may be a superior indicator for estimating dilution of ELF by BAL.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R M Effros
- Department of Medicine, Medical College of Milwaukee, Wisconsin 53226
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48
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Abstract
Although the transport of solutes from air spaces to plasma has been extensively studied, comparatively little information is available concerning solute equilibration between the plasma and the epithelial lining fluid (ELF) of air-filled lungs. In the present study, 11 lipophobic indicators varying in molecular mass between 22 and 80,000 Da were injected intravenously and/or intramuscularly into anesthetized rats in a manner designed to keep blood concentrations constant. The animals were killed by rapid lavage of their lungs at various intervals up to 120 min after the injections had been made. Indicator concentrations in the bronchoalveolar lavage (BAL) fluid and plasma were determined, and BAL-to-plasma concentration ratios were calculated for indicators that were injected (exogenous: [14C]urea, 22Na+, [3H]mannitol, 99mTc-diethylenetriaminepentaacetate (a chelate), 51Cr-(ethylene dinitrilo)tetraacetate (a chelate), 113mIn-transferrin, human albumin, and Evans blue-labeled rat albumin) and those that were already present from the plasma and ELF (unlabeled urea, rat albumin, and rat transferrin). Leakage of exogenous indicators in the blood into the BAL fluid was observed during the lavage procedure. Leakage of [14C]urea, 22Na+, and [3H]mannitol exceeded that of the heavier solute molecules. Diffusion of proteins and the labeled chelates into the ELF before lavage occurred at similar rates, suggesting vesicular transport. Use of rapidly diffusible solutes such as urea for determining dilution of ELF by BAL should be accompanied by intravascular injections of labeled solutes to correct for diffusion from the blood during lavage. Alternatively, labeled chelates or serum proteins can be used to estimate dilution of ELF by BAL. Interstitial sampling may be inevitable if the epithelium has been injured before lavage.
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Affiliation(s)
- N H Feng
- Division of Pulmonary and Critical Care Medicine, Medical College of Wisconsin, Milwaukee 53226
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49
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Abstract
A study was conducted to determine whether differences in the concentrations of large molecules between the air space and perfusate solutions altered the rates at which fluid was reabsorbed from isolated fluid-filled perfused rat lungs. Four groups of experiments were conducted: 1) 5 g/dl albumin in the air spaces and perfusate, 2) 15 g/dl albumin in the air space and 5 g/dl albumin in the perfusate, 3) 5 g/dl albumin in the air space and 15 g/dl albumin in the perfusate, and 4) a mixture of 5 g/dl albumin and 7 g/dl Dextran 70 in the air spaces and 5 g/dl albumin in the perfusate. Fluid reabsorption was determined by following the concentration of albumin labeled with Evans blue (T-1824) in the air space and perfusate compartments. Because leakage of protein between the air space and perfusate compartments is very slow, increases in T-1824 concentrations in the air spaces indicated loss of fluid from this compartment, whereas decreases in these concentrations in the perfusate compartment provided evidence of fluid transport into the vasculature. Approximately 30% of the air space fluid was reabsorbed in a 2-h period, and virtually all of this fluid reached the perfusate compartment. Despite oncotic differences that ranged from -65 to 65 Torr, variations in air space or perfusate albumin concentrations did not have a significant effect on this process. A 30% decrease in fluid reabsorption was observed when dextran was in the air space solution, but this decrease did not appear to be due to the oncotic properties of this solution because albumin did not have a measurable effect on reabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- R M Effros
- Division of Pulmonary and Critical Care Medicine, Medical College of Wisconsin, Milwaukee 53226
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50
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Elsayed N, Hacker A, Mustafa M, Kuehn K, Schrauzer G. Effects of decreased glutathione peroxidase activity on the pentose phosphate cycle in mouse lung. Biochem Biophys Res Commun 1982; 104:564-9. [PMID: 7073702 DOI: 10.1016/0006-291x(82)90674-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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