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Zakharchenko A, Rock CA, Thomas TE, Keeney S, Hall EJ, Takano H, Krieger AM, Ferrari G, Levy RJ. Inhibition of advanced glycation end product formation and serum protein infiltration in bioprosthetic heart valve leaflets: Investigations of anti-glycation agents and anticalcification interactions with ethanol pretreatment. Biomaterials 2022; 289:121782. [PMID: 36099713 PMCID: PMC10015409 DOI: 10.1016/j.biomaterials.2022.121782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/22/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022]
Abstract
Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol. In vitro, each of these agents significantly inhibited AGE-serum protein infiltration in BP. However, in 28-day rat subdermal BP implants only orally administered PYR demonstrated significant inhibition of AGE and serum protein uptake. Furthermore, BP PYR preincubation of BP mitigated AGE-serum protein SVD mechanisms in vitro, and demonstrated mitigation of both AGE-serum protein uptake and reduced calcification in vivo in 28-day rat subdermal BP explants. Inhibition of BP calcification as well as inhibition of AGE-serum protein infiltration was observed in 28-day rat subdermal BP explants pretreated with ethanol followed by PYR preincubation. In conclusion, AGE-serum protein and calcification SVD pathophysiology are significantly mitigated by both PYR oral therapy and PYR and ethanol pretreatment of BP.
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Affiliation(s)
- Andrey Zakharchenko
- The Pediatric Heart Valve Center, Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Christopher A Rock
- The Pediatric Heart Valve Center, Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Tina E Thomas
- The Pediatric Heart Valve Center, Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Samuel Keeney
- The Pediatric Heart Valve Center, Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Emily J Hall
- The Pediatric Heart Valve Center, Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Hajime Takano
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Abba M Krieger
- Department of Statistics, The Wharton School, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Giovanni Ferrari
- Departments of Surgery and Biomedical Engineering, Columbia University, New York, NY, 10032, USA
| | - Robert J Levy
- The Pediatric Heart Valve Center, Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
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Rock CA, Keeney S, Zakharchenko A, Takano H, Spiegel DA, Krieger AM, Ferrari G, Levy RJ. Model studies of advanced glycation end product modification of heterograft biomaterials: The effects of in vitro glucose, glyoxal, and serum albumin on collagen structure and mechanical properties. Acta Biomater 2021; 123:275-285. [PMID: 33444798 DOI: 10.1016/j.actbio.2020.12.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/17/2020] [Accepted: 12/22/2020] [Indexed: 01/01/2023]
Abstract
Glutaraldehyde cross-linked heterograft tissues, bovine pericardium (BP) or porcine aortic valves, are the leaflet materials in bioprosthetic heart valves (BHV) used in cardiac surgery for heart valve disease. BHV fail due to structural valve degeneration (SVD), often with calcification. Advanced glycation end products (AGE) are post-translational, non-enzymatic reaction products from sugars reducing proteins. AGE are present in SVD-BHV clinical explants and are not detectable in un-implanted BHV. Prior studies modeled BP-AGE formation in vitro with glyoxal, a glucose breakdown product, and serum albumin. However, glucose is the most abundant AGE precursor. Thus, the present studies investigated the hypothesis that BHV susceptibility to glucose related AGE, together with serum proteins, results in deterioration of collagen structure and mechanical properties. In vitro experiments studied AGE formation in BP and porcine collagen sponges (CS) comparing 14C-glucose and 14C-glyoxal with and without bovine serum albumin (BSA). Glucose incorporation occurred at a significantly lower level than glyoxal (p<0.02). BSA co-incubations demonstrated reduced glyoxal and glucose uptake by both BP and CS. BSA incubation caused a significant increase in BP mass, enhanced by glyoxal co-incubation. Two-photon microscopy of BP showed BSA induced disruption of collagen structure that was more severe with glucose or glyoxal co-incubation. Uniaxial testing of CS demonstrated that glucose or glyoxal together with BSA compared to controls, caused accelerated deterioration of viscoelastic relaxation, and increased stiffness over a 28-day time course. In conclusion, glucose, glyoxal and BSA uniquely contribute to AGE-mediated disruption of heterograft collagen structure and deterioration of mechanical properties.
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Affiliation(s)
- Christopher A Rock
- Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
| | - Samuel Keeney
- Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
| | - Andrey Zakharchenko
- Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
| | - Hajime Takano
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States
| | - David A Spiegel
- Department of Chemistry, Yale University, New Haven, CT, 06520, United States
| | - Abba M Krieger
- Department of Statistics, The Wharton School, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Giovanni Ferrari
- Departments of Surgery and Biomedical Engineering, Columbia University, New York, NY, 10032, United States
| | - Robert J Levy
- Division of Cardiology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States.
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Frasca A, Xue Y, Kossar AP, Keeney S, Rock C, Zakharchenko A, Streeter M, Gorman RC, Grau JB, George I, Bavaria JE, Krieger A, Spiegel DA, Levy RJ, Ferrari G. Glycation and Serum Albumin Infiltration Contribute to the Structural Degeneration of Bioprosthetic Heart Valves. JACC Basic Transl Sci 2020; 5:755-766. [PMID: 32875167 PMCID: PMC7452200 DOI: 10.1016/j.jacbts.2020.06.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/02/2020] [Accepted: 06/02/2020] [Indexed: 12/31/2022]
Abstract
Two novel and interacting mechanisms contributing to BHV SVD are reported: glycation and serum albumin infiltration. Glycation product formation and serum albumin deposition were observed in 45 clinical BHV explanted due to SVD as well as BHV tissue subcutaneously implanted in rats. In vitro exposure to glycation and serum albumin elicited collagen network misalignment similar to that seen in clinical and rat explant BHV tissue. Glycation was sufficient to impair BHV hydrodynamic function in ISO-5840-compliant pulse duplication testing and concomitant serum albumin infiltration exacerbated these effects.
Valvular heart diseases are associated with significant cardiovascular morbidity and mortality, and often require surgical and/or percutaneous repair or replacement. Valve replacement is limited to mechanical and biological prostheses, the latter of which circumvent the need for lifelong anticoagulation but are subject to structural valve degeneration (SVD) and failure. Although calcification is heavily studied, noncalcific SVD, which represent roughly 30% of BHV failures, is relatively underinvestigated. This original work establishes 2 novel and interacting mechanisms—glycation and serum albumin incorporation—that occur in clinical valves and are sufficient to induce hallmarks of structural degeneration as well as functional deterioration.
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Key Words
- AGE, advanced glycation end product
- BHV, bioprosthetic heart valve
- BP, bovine pericardium
- CML, N-carboxymethyl-lysine
- EOA, effective orifice area
- HSA, human serum albumin
- IHC, immunohistochemistry
- PBS, phosphate-buffered saline
- SAVR, surgical aortic valve replacement
- SHG, second harmonic generation
- SVD, structural valve degeneration
- TAVR, transcatheter aortic valve replacement
- advanced glycation end products
- aortic valve disease
- biomaterial
- bioprosthetic heart valve
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Affiliation(s)
- Antonio Frasca
- Department of Surgery, Columbia University, New York, New York
| | - Yingfei Xue
- Department of Surgery, Columbia University, New York, New York
| | | | - Samuel Keeney
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Christopher Rock
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Andrey Zakharchenko
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Matthew Streeter
- Department of Chemistry, Yale University, New Haven, Connecticut
| | - Robert C Gorman
- Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Juan B Grau
- Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Isaac George
- Department of Surgery, Columbia University, New York, New York
| | - Joseph E Bavaria
- Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Abba Krieger
- Department of Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David A Spiegel
- Department of Chemistry, Yale University, New Haven, Connecticut
| | - Robert J Levy
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
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Affiliation(s)
- A M Cumming
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, U.K
| | - S Keeney
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, U.K
| | - A Salden
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, U.K
| | - D Shanks
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, U.K
| | - C R M Hay
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, U.K
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Hay CRM, Oilier W, Pepper L, Cumming A, Keeney S, Goodeve AC, Colvin BT, Hill FGH, Preston FE, Peake IR. HLA Class II Profile: A Weak Determinant of Factor VIII Inhibitor Development in Severe Haemophilia A. Thromb Haemost 2018. [DOI: 10.1055/s-0038-1655944] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
SummaryThe risk of developing factor VIII inhibitor antibodies in haemophilia A may relate both to factor VIII genotype and genes within the HLA complex known to influence immune response. We investigated a cohort of 176 patients with severe haemophilia A and with either high-level inhibitors (>10BU/ml) or with no history of an inhibitor, stratified according to the presence or absence of the factor VIII gene intron 22 inversion.HLA DRB1, DQA1 and DQB1 polymorphisms were determined by PCR. HLA frequencies from 137 United Kingdom controls were used for comparison. HLA phenotype frequency differences, expressed as odds ratios with 95% confidence intervals were as follows: HLA- DRB*1501, DQB 1*0602 and DQA1*0102 were all increased in frequency in patients with inhibitors, only DQA1*0102 reaching statistical significance (OR 2.7,1.2-5.9). These alleles form part of an established HLA haplotype. The frequencies of HLA-DRB 1*1501, DQB1*0602 and DQA1*0102 were particularly raised in patients with inhibitors and a factor VIII gene intron 22 inversion, although again only DQA1*0102 achieved significance (OR 3.1, 1.0-10.1). The frequency of DRB 1*01, DQB 1 *0501, DQA 1*0101 were also increased in inhibitor patients lacking the intron 22 inversion although this failed to achieve statistical significance. This data suggests that HLA class II profile constitutes a weak risk factor for developing inhibitor antibodies to factor VIII. This may be more pronounced in patients with an intron 22 inversion.
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Affiliation(s)
- C R M Hay
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, Ladywood, UK
| | - W Oilier
- Arthritis and Rheumatism Council Epidemiology Research Unit, Manchester Medical School, Manchester, Ladywood, UK
| | - L Pepper
- Arthritis and Rheumatism Council Epidemiology Research Unit, Manchester Medical School, Manchester, Ladywood, UK
| | - A Cumming
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, Ladywood, UK
| | - S Keeney
- The University Department of Haematology, Manchester Royal Infirmary, Manchester, Ladywood, UK
| | - A C Goodeve
- Department of Haematology, Royal Hallamshire Hospital, Sheffield, Ladywood, UK
| | - B T Colvin
- Department of Haematology, Royal London Hospital, Whitechapel, Ladywood, UK
| | - F G H Hill
- Department of Haematology, Birmingham Children’s Hospital, Birmingham, Ladywood, UK
| | - F E Preston
- Department of Haematology, Royal Hallamshire Hospital, Sheffield, Ladywood, UK
| | - I R Peake
- Department of Haematology, Royal Hallamshire Hospital, Sheffield, Ladywood, UK
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Standen GR, Mazurier C, Gaucher C, Cumming A, Keeney S, Bidwell J, Bowen DJ. Type 2N von Willebrand Disease: Rapid Genetic Diagnosis of G2811A (R854Q), C2696T (R816W), T2701A (H817Q) and G2823T (C858F) – Detection of a Novel Candidate Type 2N Mutation: C2810T (R854W). Thromb Haemost 2017. [DOI: 10.1055/s-0037-1615134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
SummaryThe majority of patients with type 2N von Willebrand disease (VWD type 2N) have mutations in the region of the von Willebrand factor (VWF) gene encoding the factor VIII binding domain of VWF. Two mutations predominate among VWD type 2N patients: G2811A and C2696T, which respectively bring about the amino acid substitutions R854Q and R816W in VWF. Several other mutations have been found in VWD type 2N, including T2701A (H817Q) and G2823T (C858F). We have developed a genetic test which permits rapid screening for these four mutations in a single polymerase chain reaction (PCR). The test employs induced heteroduplex formation using two universal heteroduplex generators, one of which detects G2811A (R854Q) and G2823T (C858F), the other detects C2696T (R816W) and T2701A (H817Q). The allele frequency of the common G2811A (R854Q) mutation was investigated in the local (S. Wales) population by examination of 216 VWF genes (108 individuals) and was found to be 0.01. The heteroduplex-based test additionally detected a novel candidate type 2N mutation, C2810T (R854W) and a previously described polymorphism, G2805A (R852Q). The polymorphism showed allele frequencies of 0.92 (G nucleotide) and 0.08 (A nucleotide) in the population study.
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McCauley CO, McKenna HP, Keeney S, McLaughlin DF. Concept analysis of recovery in mental illness in young adulthood. J Psychiatr Ment Health Nurs 2015; 22:579-89. [PMID: 26148795 DOI: 10.1111/jpm.12245] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/12/2015] [Indexed: 11/29/2022]
Abstract
Recovery, as a concept, emerged as a core philosophy of the service user movement that began in the late 1960s and 1970s. Previous reviews on recovery in mental health have presented definitions or a conceptual framework; however, over time it has been open to disparate interpretations. The aim of this paper was to conduct the first concept analysis of mental health recovery in young adulthood within various multidisciplinary contexts. Rodgers's (2000) six-stepped evolutionary method enabled the analysis of recovery's conceptual characteristics, the identification of an exemplar and the proposition of a hypothesis with implications for practice. This analysis has revealed the derivation of the term recovery does not convey its identified conceptual characteristics. Identified attributes include the reawakening of hope, reclaiming a positive self and meaning through personal growth. Antecedents include the disruption of illness, stigmatization, internal inventory and contemplative recovery. Identified consequences include the return to normality, reconstruction of self and active social connection. The new conceptual definition is the reawakening of hope and rediscovery of a positive sense of self through finding meaning and purpose within personal growth and connection using creative self-care coping strategies. This paper reveals an apparent disparity between professional and personal interpretations of recovery. Therefore, the implication for mental health nursing is the congruence of recovery-orientated practice with the process of recovery experienced by young adult service users.
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Affiliation(s)
- C O McCauley
- Institute of Nursing and Health Research, Ulster University, Derry City, UK
| | - H P McKenna
- Institute of Nursing and Health Research, Ulster University, Coleraine, UK
| | - S Keeney
- Institute of Nursing and Health Research, Ulster University, Jordanstown, UK
| | - D F McLaughlin
- Institute of Nursing and Health Research, Ulster University, Jordanstown, UK
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Jopling H, Keeney S, Ivison F, Tetlow L, Chaloner C. Substrate variations demonstrate the importance of TPMT genotyping analysis as a quality control tool for age-related TPMT phenotyping stratification. Clin Biochem 2014. [DOI: 10.1016/j.clinbiochem.2014.04.052] [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: 10/25/2022]
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McIlfatrick S, Keeney S, McKenna H, McCarley N, McIlwee G. Exploring the actual and potential role of the primary care nurse in the prevention of cancer: a mixed methods study. Eur J Cancer Care (Engl) 2013; 23:288-99. [DOI: 10.1111/ecc.12119] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2013] [Indexed: 11/29/2022]
Affiliation(s)
- S. McIlfatrick
- Institute of Nursing and Health Research; University of Ulster; Belfast UK
| | - S. Keeney
- Institute of Nursing and Health Research; University of Ulster; Belfast UK
| | - H. McKenna
- Research and Innovation; University of Ulster; Belfast UK
| | - N. McCarley
- Institute of Nursing and Health Research; University of Ulster; Belfast UK
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10
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Cutcliffe JR, McKenna H, Keeney S, Stevenson C, Jordan J. 'Straight from the horse's mouth': rethinking and reconfiguring services in Northern Ireland in response to suicidal young men. J Psychiatr Ment Health Nurs 2013; 20:466-72. [PMID: 23145993 DOI: 10.1111/jpm.12012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The aim of this study was to explore the knowledge, attitudes and behaviours of people in mid-life towards cancer prevention. The study was undertaken in Northern Ireland between 2003 and 2007. This was a mixed methods study using a sequential exploratory design. The theoretical framework was the Theory of Planned Behaviour and the methodology was based on Sutton's framework. There were three methodological stages in the study using focus groups, a large cross-sectional survey and a volunteer sample survey. This paper focuses on the findings of the cross-sectional survey relating to the attitudes of people in mid-life towards cancer and cancer prevention. Findings are considered in relation to the respondents' level of knowledge, age, gender, level of educational attainment and socio-economic status. Evidence from this study shows that attitudes towards cancer and cancer prevention are associated significantly with level of knowledge about cancer, gender, socio-economic status and level of educational attainment. In conclusion, the evidence from this study shows that men, those with a lower level of education, those with a lower level of knowledge and those in a lower socio-economic group were more likely to hold negative attitudes about cancer and cancer prevention.
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Affiliation(s)
- S Keeney
- Institute of Nursing Research, School of Nursing, University of Ulster, UK.
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12
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Abstract
The cysteine variant of the amino acid change tyrosine/cysteine 1584 (Y/C1584) in von Willebrand factor (VWF) has previously been shown to cosegregate with increased susceptibility of VWF to proteolysis by ADAMTS13. It is not known whether C1584 itself confers increased proteolysis or is linked to a causative change elsewhere in VWF. To address whether C1584 underlies enhanced susceptibility of VWF to ADAMTS13-mediated proteolysis, a single family comprising two heterozygous Y/C1584 individuals and four homozygous Y/Y1584 individuals was investigated. The essential regions of the VWF gene were sequenced in all six individuals and ADAMTS13-mediated proteolysis of plasma VWF was assessed for each individual. Comparison of the VWF coding sequences for the Y/C1584 individuals with those for the Y/Y1584 individuals revealed that two amino acid variants were unique to the heterozygotes: R484 and C1584. The plasma VWF of the two heterozygotes showed increased susceptibility to proteolysis in vitro compared with that of the four homozygotes. In the present study we demonstrate that R484, in the absence of C1584, does not influence VWF proteolysis. Enhanced proteolysis occurred only in the presence of Cys1584. Thus, Cys1584 is necessary for increased susceptibility of VWF to proteolysis by ADAMTS13.
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Affiliation(s)
- S Keeney
- Molecular Diagnostics Centre, Manchester Royal Infirmary, Manchester, UK
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13
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Rice F, Cullen P, McKenna H, Kelly B, Keeney S, Richey R. Clinical supervision for mental health nurses in Northern Ireland: formulating best practice guidelines. J Psychiatr Ment Health Nurs 2007; 14:516-21. [PMID: 17635261 DOI: 10.1111/j.1365-2850.2007.01101.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nurses work in a constantly challenging and changing environment. Within this context, there is a continuing need for support. Such support will help increase morale, decrease strain and burnout, and encourage self-awareness and self-expression. Clinical supervision address all these issues and enhances the quality of care for patients. While clinical supervision is a policy imperative in Northern Ireland, it was clear that there were problems in its implementation in mental health nursing. The aim of this project was to explore ways to make clinical supervision available to all mental health nurses and to improve and evaluate their contribution to patient care. The research team undertook a comprehensive literature review and a baseline survey of relevant stakeholders. Results represent the outcome of the group work. They will assist healthcare providers to develop local policies and procedures on clinical supervision for practising mental health nurses.
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Affiliation(s)
- F Rice
- Nursing and Midwifery Advisory Group, Department of Health, Social Services & Public Safety, University of Ulster, Belfast, UK
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14
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Liebe B, Petukhova G, Barchi M, Bellani M, Braselmann H, Nakano T, Pandita TK, Jasin M, Fornace A, Meistrich ML, Baarends WM, Schimenti J, de Lange T, Keeney S, Camerini-Otero RD, Scherthan H. Mutations that affect meiosis in male mice influence the dynamics of the mid-preleptotene and bouquet stages. Exp Cell Res 2006; 312:3768-81. [PMID: 17010969 DOI: 10.1016/j.yexcr.2006.07.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [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] [Received: 02/02/2006] [Revised: 07/20/2006] [Accepted: 07/22/2006] [Indexed: 01/15/2023]
Abstract
Meiosis pairs and segregates homologous chromosomes and thereby forms haploid germ cells to compensate the genome doubling at fertilization. Homologue pairing in many eukaryotic species depends on formation of DNA double strand breaks (DSBs) during early prophase I when telomeres begin to cluster at the nuclear periphery (bouquet stage). By fluorescence in situ hybridization criteria, we observe that mid-preleptotene and bouquet stage frequencies are altered in male mice deficient for proteins required for recombination, ubiquitin conjugation and telomere length control. The generally low frequencies of mid-preleptotene spermatocytes were significantly increased in male mice lacking recombination proteins SPO11, MEI1, MLH1, KU80, ubiquitin conjugating enzyme HR6B, and in mice with only one copy of the telomere length regulator Terf1. The bouquet stage was significantly enriched in Atm(-/-), Spo11(-/-), Mei1(m1Jcs/m1Jcs), Mlh1(-/-), Terf1(+/-) and Hr6b(-/-) spermatogenesis, but not in mice lacking recombination proteins DMC1 and HOP2, the non-homologous end-joining DNA repair factor KU80 and the ATM downstream effector GADD45a. Mice defective in spermiogenesis (Tnp1(-/-), Gmcl1(-/-), Asm(-/-)) showed wild-type mid-preleptotene and bouquet frequencies. A low frequency of bouquet spermatocytes in Spo11(-/-)Atm(-/-) spermatogenesis suggests that DSBs contribute to the Atm(-/-)-correlated bouquet stage exit defect. Insignificant changes of bouquet frequencies in mice with defects in early stages of DSB repair (Dmc1(-/-), Hop2(-/-)) suggest that there is an ATM-specific influence on bouquet stage duration. Altogether, it appears that several pathways influence telomere dynamics in mammalian meiosis.
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Affiliation(s)
- B Liebe
- Max-Planck-Inst. for Molecular Genetics, Ihnestr. 73, D-14195 Berlin, Germany
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15
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Abstract
Homologous recombination is essential for accurate chromosome segregation during meiosis in most sexual organisms. Meiotic recombination is initiated by the formation of DSBs (DNA double-strand breaks) made by the Spo11 protein. We review here recent findings pertaining to protein–protein interactions important for DSB formation, the mechanism of an early step in the processing of Spo11-generated DSBs, and regulation of DSB formation by protein kinases.
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Affiliation(s)
- S Keeney
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., Box 97, New York, NY 10021, USA.
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16
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Keeney S, Mitchell M, Goodeve A. The molecular analysis of haemophilia A: a guideline from the UK haemophilia centre doctors' organization haemophilia genetics laboratory network. Haemophilia 2005; 11:387-97. [PMID: 16011593 DOI: 10.1111/j.1365-2516.2005.01111.x] [Citation(s) in RCA: 50] [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: 11/30/2022]
Abstract
Haemophilia A is a common inherited bleeding disorder that has a well-understood pathophysiology. Our understanding of the molecular genetics of the disease has allowed the development of comprehensive carrier and prenatal diagnosis for this single gene defect. Continuing technological developments improve our ability to provide genetic analysis in a rapid and cost effective manner. This guideline aims to provide advice on current best laboratory practice when approaching genetic diagnosis of haemophilia A.
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Affiliation(s)
- S Keeney
- Department of Haematology, Molecular Diagnostics Centre, Manchester Royal Infirmary, Manchester, UK.
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Mitchell M, Keeney S, Goodeve A. The molecular analysis of haemophilia B: a guideline from the UK haemophilia centre doctors' organization haemophilia genetics laboratory network. Haemophilia 2005; 11:398-404. [PMID: 16011594 DOI: 10.1111/j.1365-2516.2005.01112.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [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: 11/28/2022]
Abstract
Haemophilia B is one of the most common inherited bleeding disorders and has a well understood pathophysiology. Our understanding of the molecular genetics of the disease has allowed the development of comprehensive carrier and prenatal diagnosis for this single gene disorder. Continuing technological developments improve our ability to provide genetic analysis in a rapid and cost-effective manner. This guideline aims to provide advice on current best laboratory practice when approaching genetic diagnosis of haemophilia B.
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Affiliation(s)
- M Mitchell
- Molecular Genetics Unit, Reference Centre for Haemostatic and Thrombotic Disorders, St. Thomas' Hospital, London, UK.
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Kucher TV, Oleski SL, Keeney S. Diagnosis of deep venous thrombosis and pulmonary embolus in patients with mucinous variant adenocarcinoma. J Thromb Haemost 2005; 3:591-2. [PMID: 15748258 DOI: 10.1111/j.1538-7836.2005.01156.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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19
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Bolton-Maggs PHB, Peretz H, Butler R, Mountford R, Keeney S, Zacharski L, Zivelin A, Seligsohn U. A common ancestral mutation (C128X) occurring in 11 non-Jewish families from the UK with factor XI deficiency. J Thromb Haemost 2004; 2:918-24. [PMID: 15140127 DOI: 10.1111/j.1538-7836.2004.00723.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Factor XI (FXI) deficiency is a mild bleeding disorder that is particularly common in Ashkenazi Jews, but has been reported in all populations. In Jews, two FXI gene (F11) mutations (a stop codon in exon 5, E117X, type II, and a point mutation in exon 9, F283L, type III) are particularly common, but in other populations a variety of different mutations have been described. In the Basque region of France one mutation, C38R in exon 3, was found in eight of 12 families studied, haplotype analysis suggesting a founder effect. In the course of screening 78 unrelated individuals (including 15 Jewish and 12 Asian) we have found 10 Caucasian non-Jewish patients with the mutation C128X in exon 5. Individuals were investigated because of a personal or family history of bleeding, or finding a prolonged activated partial thromboplastin time. Individuals negative for the type II and type III mutations were screened by a combination of SSCP and heteroduplex analysis. The C128X mutation was found in 10 families (one previously described). Among three individuals with severe FXI deficiency, one was homozygous for the C128X mutation, and two were compound heterozygotes for the C128X and another mutation; other individuals were carriers of the C128X mutation. This is a nonsense mutation producing a truncated protein; individuals have FXI antigen levels concordant with FXI coagulant activity. Haplotype analysis of 11 families, including a further kindred previously reported from the USA, but which originally came from the UK (in which the index patient was homozygous for C128X), suggests a founder effect.
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Affiliation(s)
- P H B Bolton-Maggs
- Department of Clinical Haematology, Manchester Royal Infirmary, Manchester, UK.
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Gilligan OM, Keeney S, Watson P, Hay CRM, Cumming A. Type 2M von Willebrand disease: correlation of phenotype with genotype? J Thromb Haemost 2003. [DOI: 10.1111/j.1538-7836.2003.tb03820.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Homologous recombination is essential during meiosis in most sexually reproducing organisms. In budding yeast, and most likely in other organisms as well, meiotic recombination proceeds via the formation and repair of DNA double-strand breaks (DSBs). These breaks appear to be formed by the Spo11 protein, with assistance from a large number of other gene products, by a topoisomerase-like transesterase mechanism. Recent studies in fission yeast, multicellular fungi, flies, worms, plants, and mammals indicate that the role of Spo11 in meiotic recombination initiation is highly conserved. This chapter reviews the properties of Spo11 and the other gene products required for meiotic DSB formation in a number of organisms and discusses ways in which recombination initiation is coordinated with other events occurring in the meiotic cell.
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Affiliation(s)
- S Keeney
- Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, and Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10021, USA
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Abstract
von Willebrand disease (VWD) is a common autosomally inherited bleeding disorder associated with mucosal or trauma-related bleeding in affected individuals. VWD results from either a quantitative or qualitative deficiency of von Willebrand factor (VWF)--a glycoprotein with essential roles in primary haemostasis and as a carrier of coagulation factor VIII (FVIII) in the circulation. In recent years the identification of mutations in the VWF gene in patients with VWD has improved our understanding of the structure and function of the VWF protein, and has illustrated the importance of specific regions of VWF for its interaction with other components of the vasculature. The underlying genetic lesions and associated molecular pathology have been identified in many cases of type 2A, type 2B, type 2M, type 2N and type 3 VWD. However in the most common variant, type 1 VWD, the causative molecular defect is unknown in the large majority of cases. In the absence of an understanding of the molecular pathology underlying type 1 VWD, precise diagnosis and classification of this common disorder remains problematic.
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Affiliation(s)
- S Keeney
- University Department of Haematology, Royal Infirmary, Manchester, UK.
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Abstract
The Delphi technique is an approach used to gain consensus among a panel of experts. This is normally achieved through a series of rounds where information is fed back to panel members using questionnaires. It has been used extensively within social science research and is being increasingly employed by nurse researchers. This popularity has meant that the technique has been adapted in various ways and there is the possibility that the rigour associated with the original format has been threatened. This signals the need for a critical review of the Delphi as a robust and systematic approach to data collection. While there is a great volume of literature surrounding the "Delphi", there is a dearth of papers critically analysing the technique. This paper aims to examine critically the Delphi technique from a range of perspectives. Discussion will focus on problems of definition and the advantages and disadvantages and the techniques' application in nursing. The critique will be structured through an analysis of the key aspects of the Delphi process. These key aspects include analysis of sampling, anonymity, use of experts, rounds and application. The critical analysis highlights the increasing popularity of the Delphi and the modifications to the process which may cause methodological problems. Ultimately, the Delphi has much to offer in terms of gaining consensus from a wide range of individuals on specific topics.
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Affiliation(s)
- S Keeney
- Centre for Nursing Research, University of Ulster, Shore Road, Newtownabbey BT37 0QB, Northern Ireland, UK.
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Mahadevaiah SK, Turner JM, Baudat F, Rogakou EP, de Boer P, Blanco-Rodríguez J, Jasin M, Keeney S, Bonner WM, Burgoyne PS. Recombinational DNA double-strand breaks in mice precede synapsis. Nat Genet 2001; 27:271-6. [PMID: 11242108 DOI: 10.1038/85830] [Citation(s) in RCA: 666] [Impact Index Per Article: 29.0] [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: 01/22/2023]
Abstract
In Saccharomyces cerevisiae, meiotic recombination is initiated by Spo11-dependent double-strand breaks (DSBs), a process that precedes homologous synapsis. Here we use an antibody specific for a phosphorylated histone (gamma-H2AX, which marks the sites of DSBs) to investigate the timing, distribution and Spo11-dependence of meiotic DSBs in the mouse. We show that, as in yeast, recombination in the mouse is initiated by Spo11-dependent DSBs that form during leptotene. Loss of gamma-H2AX staining (which in irradiated somatic cells is temporally linked with DSB repair) is temporally and spatially correlated with synapsis, even when this synapsis is 'non-homologous'.
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Affiliation(s)
- S K Mahadevaiah
- Division of Developmental Genetics, National Institute for Medical Research, London, UK
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Abstract
Accurate segregation of homologous chromosomes at the first meiotic division requires the tight coordination of DNA replication, homologous recombination and chromosome organization. Recent studies suggest that the initiation of meiotic recombination is mechanistically coupled to premeiotic DNA replication.
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Affiliation(s)
- F Baudat
- Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 97, New York, New York 10021, USA
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Abstract
Spo11, a protein first identified in yeast, is thought to generate the chromosome breaks that initiate meiotic recombination. We now report that disruption of mouse Spo11 leads to severe gonadal abnormalities from defective meiosis. Spermatocytes suffer apoptotic death during early prophase; oocytes reach the diplotene/dictyate stage in nearly normal numbers, but most die soon after birth. Consistent with a conserved function in initiating meiotic recombination, Dmc1/Rad51 focus formation is abolished. Spo11(-/-) meiocytes also display homologous chromosome synapsis defects, similar to fungi but distinct from flies and nematodes. We propose that recombination initiation precedes and is required for normal synapsis in mammals. Our results also support the view that mammalian checkpoint responses to meiotic recombination and/or synapsis defects are sexually dimorphic.
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Affiliation(s)
- F Baudat
- Cell Biology Program Memorial Sloan-Kettering Cancer Center New York, NY 10021, USA
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Hasson F, Keeney S, McKenna H. Research guidelines for the Delphi survey technique. J Adv Nurs 2000; 32:1008-15. [PMID: 11095242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Consensus methods such as the Delphi survey technique are being employed to help enhance effective decision-making in health and social care. The Delphi survey is a group facilitation technique, which is an iterative multistage process, designed to transform opinion into group consensus. It is a flexible approach, that is used commonly within the health and social sciences, yet little guidance exists to help researchers undertake this method of data collection. This paper aims to provide an understanding of the preparation, action steps and difficulties that are inherent within the Delphi. Used systematically and rigorously, the Delphi can contribute significantly to broadening knowledge within the nursing profession. However, careful thought must be given before using the method; there are key issues surrounding problem identification, researcher skills and data presentation that must be addressed. The paper does not claim to be definitive; it purports to act as a guide for those researchers who wish to exploit the Delphi methodology.
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Affiliation(s)
- F Hasson
- Centre for Nursing Research, University of Ulster, Newtownabbey, Northern Ireland.
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Abstract
The Audit Commission's (1994) report Finding a Place states that mental health problems are a major cause of disruption and difficulty in people's lives and that in any one year more than a quarter of all people suffer to some degree. The report asserts that the majority visit their general practitioner (GP) and less than half of the people concerned are recognized as having a mental health problem. Many recover over a period of weeks or months and are best served by community services. Only those with the most serious conditions need specialized care or admission to hospital. On a local level in Northern Ireland, the policy of reducing the number of long-stay patients began in the 1960s with a call for people with mental illness to be integrated into the community. This has had major implications for community mental health services and for community psychiatric nursing. The aim of this study into one community psychiatric nursing service (CPNS) in Northern Ireland is to inform managers and professionals about the nature and shape of this service and to facilitate wider discussion on how to plan and deliver it in the future.
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Affiliation(s)
- H McKenna
- School of Health Sciences, University of Ulster, Shore Road, Newtownabbey, Co. Antrim, BT37 OQB, Northern Ireland, UK
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Keeney S. Meiotic machinations. Nat Genet 2000; 25:248. [PMID: 10888862 DOI: 10.1038/76982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
The desire to reduce the length of waiting lists in the modern health service means that strategies for decreasing the length of hospital stay are exercising the minds of service planners. This has led to renewed emphasis on well planned discharge policies and procedures. The aim of this study was to analyse all discharge policies and procedures currently in use in one large integrated NHS trust in Northern Ireland and formulate a Corporate Discharge Policy for general use in NHS trusts. Objectives of the study included examining the current process of discharge, reviewing the interface between ward staff and district nursing services and examining the quality and standard of documentation in use. Findings indicate the need for standardization of the discharge planning process and sufficient notice of discharge, and for clarification and education regarding staff roles, the importance of multidisciplinary working, and the lack of quality communication between acute and community services.
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Affiliation(s)
- H McKenna
- School of Health Sciences, University of Ulster, Northern Ireland
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Cha RS, Weiner BM, Keeney S, Dekker J, Kleckner N. Progression of meiotic DNA replication is modulated by interchromosomal interaction proteins, negatively by Spo11p and positively by Rec8p. Genes Dev 2000; 14:493-503. [PMID: 10691741 PMCID: PMC316381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Spo11p is a key mediator of interhomolog interactions during meiosis. Deletion of the SPO11 gene decreases the length of S phase by approximately 25%. Rec8p is a key coordinator of meiotic interhomolog and intersister interactions. Deletion of the REC8 gene increases S-phase length, by approximately 10% in wild-type and approximately 30% in a spo11Delta background. Thus, the progression of DNA replication is modulated by interchromosomal interaction proteins. The spo11-Y135F DSB (double strand break) catalysis-defective mutant is normal for S-phase modulation and DSB-independent homolog pairing but is defective for later events, formation of DSBs, and synaptonemal complexes. Thus, earlier and later functions of Spo11 are defined. We propose that meiotic S-phase progression is linked directly to development of specific chromosomal features required for meiotic interhomolog interactions and that this feedback process is built upon a more fundamental mechanism, common to all cell types, by which S-phase progression is coupled to development of nascent intersister connections and/or related aspects of chromosome morphogenesis. Roles for Rec8 and/or Spo11 in progression through other stages of meiosis are also revealed.
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Affiliation(s)
- R S Cha
- Department of Molecular Biology, Harvard University, Cambridge, Massachusetts 02138 USA
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Cumming AM, Olujohungbe A, Keeney S, Singh H, Hay CR, Serjeant GR. The methylenetetrahydrofolate reductase gene C677T polymorphism in patients with homozygous sickle cell disease and stroke. Br J Haematol 1999; 107:569-71. [PMID: 10583261 DOI: 10.1046/j.1365-2141.1999.01728.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [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
Homozygosity for the methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism may cause hyperhomocysteinaemia, a recognized risk factor for stroke, in individuals with folate deficiency. Homozygous sickle cell (SS) disease is associated both with increased demands for folic acid and a tendency to develop stroke. We therefore investigated a possible role of the MTHFR C677T polymorphism in SS disease patients with stroke. Investigation of the frequency of the polymorphism in 48 patients with stroke and in 48 age-, sex- and racially-matched SS controls without stroke failed to reveal a difference between the groups (Fisher exact test, P = 0.99). Homozygosity for the MTHFR C677T polymorphism is unlikely to be a risk factor for stroke in this population with SS disease.
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Affiliation(s)
- A M Cumming
- University Department of Haematology, Royal Infirmary, Manchester, UK.
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Keeney S, Cumming A, Hay C. Mutations in von Willebrand factor multimerization domains are not a common cause of classical type 1 von Willebrand disease. Thromb Haemost 1999; 82:1446-50. [PMID: 10595636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Type 1 von Willebrand disease (vWD) is an autosomal dominant bleeding disorder of variable penetrance. It is characterised by a mild to moderate bleeding tendency and a quantitative deficiency of von Willebrand factor (vWF) with the full range of vWF multimers. Few mutations have been described which account for the mode of inheritance in dominant vWD type 1. We screened the vWF multimerization domains (regions D1-D3 of the vWF gene) of 12 unrelated patients with dominant vWD type 1 to investigate the hypothesis that multimerization of vWF sub-units may be inhibited or reduced by a "dominant negative" mechanism. Platelet-derived RNA was reverse transcribed and the resulting vWF cDNA amplified by the polymerase chain reaction (PCR) in a series of overlapping fragments. These were subjected to a combination of single-strand conformation polymorphism (SSCP) and heteroduplex analysis. This approach identified mobility shifts on acrylamide gels that represented 12 distinct SSCP and/or heteroduplex patterns in our patient group. DNA sequencing of the region encompassing each mobility shift showed these variants to represent previously described polymorphisms within the vWF coding sequence. Examination in all 12 patients for the previously described G3389T and T3445C mutations proved negative. The molecular pathology of classical type 1 vWD remains enigmatic, mutations having been identified in only a small minority of patients. A common mechanism underlying this disease state has still to be elucidated.
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Affiliation(s)
- S Keeney
- University Department of Haematology, Manchester Royal Infirmary, UK.
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Keeney S, Baudat F, Angeles M, Zhou ZH, Copeland NG, Jenkins NA, Manova K, Jasin M. A mouse homolog of the Saccharomyces cerevisiae meiotic recombination DNA transesterase Spo11p. Genomics 1999; 61:170-82. [PMID: 10534402 DOI: 10.1006/geno.1999.5956] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Saccharomyces cerevisiae Spo11 protein is thought to catalyze formation of the DNA double-strand breaks that initiate meiotic recombination. We have cloned cDNA and genomic DNA for a mouse gene encoding a protein with significant sequence similarity to conserved domains found in proteins of the Spo11p family. This putative mouse Spo11 gene maps to the distal region of chromosome 2 (homologous to human chromosome 20q13.2-q13.3) and comprises at least 12 exons, spanning approximately 15-18 kb. Strong expression of the Spo11 message is seen in juvenile and adult testis by RNA in situ hybridization, RT-PCR, and Northern blot, with much weaker expression in thymus and brain. In situ hybridization detects expression in oocytes of embryonic ovary, but not of adult ovary. RT-PCR and in situ hybridization analyses of a time course of juvenile testis development indicate that Spo11 expression begins in early meiotic Prophase I, prior to the pachytene stage, with increasing accumulation of mRNA through the pachytene stage. Taken together, these results strongly suggest that this gene encodes the functional homolog of yeast Spo11p, which in turn suggests that the mechanism of meiotic recombination initiation is conserved between yeast and mammals.
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Affiliation(s)
- S Keeney
- Molecular Biology Program, Cell Biology Program, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, New York, 10021, USA.
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Keeney S, Salden A, Hay C, Cumming A. A whole blood, multiplex PCR detection method for factor V Leiden and the prothrombin G20210A variant. Thromb Haemost 1999; 81:464-5. [PMID: 10102480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Bowen DJ, Standen GR, Mazurier C, Gaucher C, Cumming A, Keeney S, Bidwell J. Type 2N von Willebrand disease: rapid genetic diagnosis of G2811A (R854Q), C2696T (R816W), T2701A (H817Q) and G2823T (C858F)--detection of a novel candidate type 2N mutation: C2810T (R854W). Thromb Haemost 1998; 80:32-6. [PMID: 9684781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The majority of patients with type 2N von Willebrand disease (VWD type 2N) have mutations in the region of the von Willebrand factor (VWF) gene encoding the factor VIII binding domain of VWF. Two mutations predominate among VWD type 2N patients: G2811A and C2696T, which respectively bring about the amino acid substitutions R854Q and R816W in VWF. Several other mutations have been found in VWD type 2N, including T2701A (H817Q) and G2823T (C858F). We have developed a genetic test which permits rapid screening for these four mutations in a single polymerase chain reaction (PCR). The test employs induced heteroduplex formation using two universal heteroduplex generators, one of which detects G2811A (R854Q) and G2823T (C858F), the other detects C2696T (R816W) and T2701A (H817Q). The allele frequency of the common G2811A (R854Q) mutation was investigated in the local (S. Wales) population by examination of 216 VWF genes (108 individuals) and was found to be 0.01. The heteroduplex-based test additionally detected a novel candidate type 2N mutation, C2810T (R854W) and a previously described polymorphism, G2805A (R852Q). The polymorphism showed allele frequencies of 0.92 (G nucleotide) and 0.08 (A nucleotide) in the population study.
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Affiliation(s)
- D J Bowen
- Arthur Bloom Center, Dept of Haematology, University of Wales College of Medicine, Cardiff, S Wales, UK
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Salden A, Keeney S, Hay CR, Cumming AM. The C677T MTHFR variant and the risk of venous thrombosis. Br J Haematol 1997; 99:472. [PMID: 9375781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Cumming AM, Keeney S, Salden A, Bhavnani M, Shwe KH, Hay CRM. Prevalence of the prothrombin gene G20210A variant in an UK anticoagulant clinic population. Blood Coagul Fibrinolysis 1997. [DOI: 10.1097/00001721-199710000-00034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
We have investigated the prevalence of a recently reported genetic variation in the prothrombin gene (G20210A) in patients with an objectively confirmed history of venous thrombosis, 12/219 patients (5.5%) were found to be heterozygous carriers of the 20210A allele. The incidence of the 20210A allele in a group of 164 healthy controls was 1.2% (allele frequency 0.61%, 95% CI 0.08-2.19). When patients with a known alternative hereditary risk factor for venous thrombosis (factor V Leiden mutation or deficiency of antithrombin, protein C or protein S) were excluded, the G20210A variant was found to increase the risk for venous thrombosis by approximately 5-fold (odds ratio 5.4, 95% CI 1.16-25.0). This prothrombin gene sequence variation adds further to the list of recognized genetic risk factors for thrombophilia.
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Affiliation(s)
- A M Cumming
- University Department of Haematology, Royal Infirmary, Manchester
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Cumming AM, Keeney S, Salden A, Shanks D, Hay CR. Potential misdiagnosis of factor V Leiden: a comparison of two genotyping techniques. Thromb Haemost 1997; 77:1217. [PMID: 9241760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Abstract
Meiotic recombination in S. cerevisiae is initiated by double-strand breaks (DSBs). In certain mutants, breaks accumulate with a covalently attached protein, suggesting that cleavage is catalyzed by the DSB-associated protein via a topoisomerase-like transesterase mechanism. We have purified these protein-DNA complexes and identified the protein as Spo11, one of several proteins required for DSB formation. These findings strongly implicate Spo11 as the catalytic subunit of the meiotic DNA cleavage activity. This is the first identification of a biochemical function for any of the gene products involved in DSB formation. Spo11 defines a protein family with other members in fission yeast, nematodes, and archaebacteria. The S. pombe homolog, rec12p, is also known to be required for meiotic recombination. Thus, these findings provide direct evidence that the mechanism of meiotic recombination initiation is evolutionarily conserved.
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Affiliation(s)
- S Keeney
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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Hay CR, Ollier W, Pepper L, Cumming A, Keeney S, Goodeve AC, Colvin BT, Hill FG, Preston FE, Peake IR. HLA class II profile: a weak determinant of factor VIII inhibitor development in severe haemophilia A. UKHCDO Inhibitor Working Party. Thromb Haemost 1997; 77:234-7. [PMID: 9157572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The risk of developing factor VIII inhibitor antibodies in haemophilia A may relate both to factor VIII genotype and genes within the HLA complex known to influence immune response. We investigated a cohort of 176 patients with severe haemophilia A and with either high-level inhibitors (> 10BU/ml) or with no history of an inhibitor, stratified according to the presence or absence of the factor VIII gene intron 22 inversion. HLA DRB1, DQA1 and DQB1 polymorphisms were determined by PCR. HLA frequencies form 137 United Kingdom controls were used for comparison. HLA phenotype frequency differences, expressed as odds ratios with 95% confidence intervals were as follows: HLA-DRB*1501, DQB1*0602 and DQA1*0102 were all increased in frequency in patients with inhibitors, only DQA1*0102 reaching statistical significance (OR 2.7, 1.2-5.9). These alleles form part of an established HLA haplotype. The frequencies of HLA-DRB1*1501, DQB1*0602 and DQA1*0102 were particularly raised in patients with inhibitors and a factor VIII gene intron 22 inversion, although again only DQA1*0102 achieved significance (OR 3.1, 1.0-10.1). The frequency of DRB1*01, DQB1*0501, DQA1*0101 were also increased in inhibitor patients lacking the intron 22 inversion although this failed to achieve statistical significance. This data suggests that HLA class II profile constitutes a weak risk factor for developing inhibitor antibodies to factor VIII. This may be more pronounced in patients with an intron 22 inversion.
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Affiliation(s)
- C R Hay
- University Department of Haematology, Manchester Royal Infirmary, UK.
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Saunders MJ, Tobal K, Keeney S, Liu Yin JA. Expression of diverse AML1/MTG8 transcripts is a consistent feature in acute myeloid leukemia with t(8;21) irrespective of disease phase. Leukemia 1996; 10:1139-42. [PMID: 8683993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The (8;21) chromosomal translocation occurs in 20% of adult patients with AML M2. This translocation interrupts two genes, AML1 on chromosome 21q and MTG8 (ETO) on 8q to form a chimeric gene AML1/MTG8 on the der(8) chromosome. Recent reports have shown the presence of diverse forms of transcript for this chimeric gene. Three alternative out-of-frame transcripts have been previously demonstrated (types II, III, IV) all of which have a stop codon 3' of the runt box encoding a truncated runt polypeptide. We have characterized a novel transcript (V) which is in-frame and has a stop codon 3' to the runt box. We have examined transcript diversity in 10 AML patients with t(8;21) in remission of their disease following chemotherapy or bone marrow transplantation. Specific transcripts detected at presentation in six patients were similarly expressed during remission and at relapse in two patients; thus expression of transcript diversity was unaffected by the disease phase. Alternative transcripts were unhelpful as a marker of remission quality or predictor of relapse. The significance of these diverse transcripts in leukemogenesis remains unknown.
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MESH Headings
- Base Sequence
- Chromosomes, Human, Pair 21
- Chromosomes, Human, Pair 8
- Core Binding Factor Alpha 2 Subunit
- DNA-Binding Proteins/genetics
- Gene Expression
- Humans
- Leukemia, Myeloid, Acute/drug therapy
- Leukemia, Myeloid, Acute/genetics
- Molecular Sequence Data
- Neoplasm Proteins/genetics
- Proto-Oncogene Proteins
- RUNX1 Translocation Partner 1 Protein
- Recurrence
- Remission Induction
- Transcription Factors/genetics
- Transcription, Genetic
- Translocation, Genetic
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Affiliation(s)
- M J Saunders
- University Department of Clinical Hematology, Manchester Royal Infirmary, UK
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Keeney S, Kleckner N. Communication between homologous chromosomes: genetic alterations at a nuclease-hypersensitive site can alter mitotic chromatin structure at that site both in cis and in trans. Genes Cells 1996; 1:475-89. [PMID: 9078379 DOI: 10.1046/j.1365-2443.1996.d01-257.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [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: 02/04/2023]
Abstract
BACKGROUND In vegetatively growing diploid strains of the yeast Saccharomyces cerevisiae, homologous chromosomes appear to be paired via multiple interstitial interactions, likely as a regular feature of the diploid lifestyle. We have previously suggested that this pairing is guided by direct physical interactions between intact DNA duplexes in nuclease-hypersensitive regions and that homology is sensed directly at the DNA level. RESULTS As a first test of this idea we have examined the level of DNase I sensitivity at a prominent nuclease-hypersensitive site in mitotic chromatin in strains that are either homozygous or heterozygous for a pair of alleles at this site. We find that the degree of nuclease sensitivity at this site on a given (maternal or paternal) chromosome can vary depending upon whether the homologue carries the same allele or the different allele. The data are suggestive that nuclease sensitivity is higher in the former case than in the latter, as though nuclease hypersensitivity might be increased when the two alleles match as compared to when they do not. CONCLUSIONS Formally, these observations suggest that homologous chromosomes can communicate via a mechanism that senses the status of the assayed nuclease-hypersensitive site with resultant changes in chromatin structure at that site. The observed pattern of effects is fully compatible with direct physical interactions between homologues at nuclease-hypersensitive regions, but alternative scenarios also can be envisioned. Since DNase I hypersensitive sites occur in many important regions of chromosomes, homology-dependent interactions involving such regions could potentially affect diverse processes including gene expression (e.g. transvection), chromosome organization, domain structure, and/or DNA replication patterns.
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Affiliation(s)
- S Keeney
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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Abstract
During meiosis in Saccharomyces cerevisiae, the first chemical step in homologous recombination is the occurrence of site-specific DNA double-strand breaks (DSBs). In wild-type cells, these breaks undergo resection of their 5' strand termini to yield molecules with 3' single-stranded tails. We have further characterized the breaks that accumulate in rad50S mutant stains defective in DSB resection. We find that these DSBs are tightly associated with protein via what appears to be a covalent linkage. When genomic DNA is prepared from meiotic rad50S cultures without protease treatment steps, the restriction fragments diagnostic of DSBs selectively partition to the organic-aqueous interphase in phenol extractions and band at lower than normal density in CsCl density gradients. Selective partitioning and decreased buoyant density are abolished if the DNA is treated with proteinase K prior to analysis. Similar results are obtained with sae2-1 mutant strains, which have phenotypes identical to rad50S mutants. The protein is bound specifically to the 5' strand termini of DSBs and is present at both 5' ends in at least a fraction of breaks. The stability of the complex to various protein denaturants and the strand specificity of the attachment are most consistent with a covalent linkage to DSB termini. We propose that the DSB-associated protein is the catalytic subunit of the meiotic recombination initiation nuclease and that it cleaves DNA via a covalent protein-DNA intermediate.
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Affiliation(s)
- S Keeney
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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Dualan R, Brody T, Keeney S, Nichols AF, Admon A, Linn S. Chromosomal localization and cDNA cloning of the genes (DDB1 and DDB2) for the p127 and p48 subunits of a human damage-specific DNA binding protein. Genomics 1995; 29:62-9. [PMID: 8530102 DOI: 10.1006/geno.1995.1215] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.6] [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: 01/31/2023]
Abstract
DDB is a damage-specific DNA binding protein whose binding activity is absent from a minority of cell strains from individuals with xeroderma pigmentosum Group E, a human hereditary disease characterized by defective nucleotide excision DNA repair and an increased incidence of skin cancer. The binding activity from HeLa cells is associated with polypeptides of M(r) 124,000 and 41,000 as determined by SDS-polyacrylamide gels. This report describes the isolation of full-length human cDNAs encoding each polypeptide of DDB. The predicted peptide molecular masses based on open reading frames are 127,000 and 48,000. When expressed in an in vitro rabbit reticulocyte system, the p48 subunit migrates with an M(r) of 41 kDa on SDS-polyacrylamide gels, similarly to the peptide purified from HeLa cells. There is no significant homology between the derived p48 peptide sequence and any proteins in current databases, and the derived peptide sequence of p127 has homology only with the monkey DDB p127 (98% nucleotide identity and only one conserved amino acid substitution). Using a fluorescence in situ hybridization technique, the DDB p127 locus (DDB1) was assigned to the chromosomal location 11q12-q13, and the DDB p48 locus (DDB2) to 11p11-p12.
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Affiliation(s)
- R Dualan
- Department of Molecular and Cell Biology, University of California, Berkeley 94720-3202, USA
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Abstract
We measured activated protein C (APC) anticoagulant activity in 20 healthy women at 14-20, 28 and 36 weeks gestation, and at 1 d post-partum. Significant reductions in the mean APC sensitivity ratio (APC-SR) were observed at all stages of pregnancy studied compared with the mean APC-SR obtained for baseline measurements carried out at > 8 weeks post-partum. APC resistance was seen in 8/19 (42%) and in 11/20 (55%) women at 14-20 and 28 weeks gestation respectively. The development of resistance to APC may contribute to the increased risk of thrombosis during pregnancy.
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Affiliation(s)
- A M Cumming
- University Department of Haematology, Manchester Royal Infirmary
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48
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Keeney S, Eker AP, Brody T, Vermeulen W, Bootsma D, Hoeijmakers JH, Linn S. Correction of the DNA repair defect in xeroderma pigmentosum group E by injection of a DNA damage-binding protein. Proc Natl Acad Sci U S A 1994; 91:4053-6. [PMID: 8171034 PMCID: PMC43721 DOI: 10.1073/pnas.91.9.4053] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.2] [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: 01/29/2023] Open
Abstract
Cells from a subset of patients with the DNA-repair-defective disease xeroderma pigmentosum complementation group E (XP-E) are known to lack a DNA damage-binding (DDB) activity. Purified human DDB protein was injected into XP-E cells to test whether the DNA-repair defect in these cells is caused by a defect in DDB activity. Injected DDB protein stimulated DNA repair to normal levels in those strains that lack the DDB activity but did not stimulate repair in cells from other xeroderma pigmentosum groups or in XP-E cells that contain the activity. These results provide direct evidence that defective DDB activity causes the repair defect in a subset of XP-E patients, which in turn establishes a role for this activity in nucleotide-excision repair in vivo.
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Affiliation(s)
- S Keeney
- Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720
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Reardon JT, Nichols AF, Keeney S, Smith CA, Taylor JS, Linn S, Sancar A. Comparative analysis of binding of human damaged DNA-binding protein (XPE) and Escherichia coli damage recognition protein (UvrA) to the major ultraviolet photoproducts: T[c,s]T, T[t,s]T, T[6-4]T, and T[Dewar]T. J Biol Chem 1993; 268:21301-8. [PMID: 8407968] [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: 01/30/2023] Open
Abstract
Human cells contain a protein that binds to UV-irradiated DNA with high affinity. This protein, the damaged DNA-binding protein (DDB), is absent from some xeroderma pigmentosum complementation group E cell strains; therefore, it has been suggested that it may be the damage recognition subunit of a human excision nuclease complex. However, the identity of the UV photoproduct bound by DDB and the role of this protein in nucleotide excision repair have been controversial. In this study, we used several synthetic DNA substrates, each of which contains one of the major UV photoproducts, and DDB purified to apparent homogeneity to quantify the specific binding of DDB to various photoproducts. For comparison, the binding of the same photoproducts by the Escherichia coli damage recognition protein UvrA, which is known to be a subunit of the E. coli excision nuclease, was also measured. UvrA and DDB each bound with high affinity to T[t,s]T, T[6-4]T, and T[Dewar]T, but only marginally discriminated between an undamaged oligomer and an oligomer with a T[c,s]T. In contrast to these similarities with regard to the binding to UV photoproducts, UvrA bound to another excision repair substrate, the psoralen-thymine monoadduct, with high specificity, whereas DDB was unable to distinguish between psoralen-adducted DNA and undamaged DNA. We conclude that DDB may play a special role in the repair of UV damage, but it cannot be the sole damage recognition subunit of human excision nuclease.
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Affiliation(s)
- J T Reardon
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill 27599
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Keeney S, Chang GJ, Linn S. Characterization of a human DNA damage binding protein implicated in xeroderma pigmentosum E. J Biol Chem 1993; 268:21293-300. [PMID: 8407967] [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: 01/30/2023] Open
Abstract
A human DNA damage binding protein implicated in the DNA excision repair disorder xeroderma pigmentosum E was purified to near homogeneity from HeLa cells. The protein is abundant (approximately 10(5) copies/cell) and has a native molecular weight of 154,000-163,000 as estimated by gel filtration and glycerol gradient sedimentation. DNA damage binding activity copurified with polypeptides of 124 and 41 kDa. Based on the native molecular weight, cosedimentation of both polypeptides with DNA damage binding activity on glycerol gradients, and a molar ratio of approximately 1:1 for the two polypeptides, it appears that p124 and p41 are subunits of a heterodimeric protein. Binding to damaged DNA was resistant to K+ concentrations approaching 1 M, but showed anion-specific sensitivity to Cl- concentrations above 0.5 M, suggesting that the majority of the binding energy is contributed by nonionic interactions. In contrast to previous reports, the DNA damage binding protein was shown to recognize cyclobutane pyrimidine dimers in addition to a nonphotoreactivable lesion(s), most likely the pyrimidine-pyrimidone (6-4) photoproduct.
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Affiliation(s)
- S Keeney
- Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720
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