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Howlett N, Bottoms L, Chater A, Clark AB, Clarke T, David L, Irvine K, Jones A, Jones J, Mengoni SE, Murdoch J, Pond M, Sharma S, Sims EJ, Turner DA, Wellsted D, Wilson J, Wyatt S, Trivedi D. A randomised controlled trial of energetic activity for depression in young people (READY): a multi-site feasibility trial protocol. Pilot Feasibility Stud 2021; 7:6. [PMID: 33390189 PMCID: PMC7779325 DOI: 10.1186/s40814-020-00734-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Prevalence of depression is increasing in young people, and there is a need to develop and evaluate behavioural interventions which may provide benefits equal to or greater than talking therapies or pharmacological alternatives. Exercise could be beneficial for young people living with depression, but robust, large-scale trials of effectiveness and the impact of exercise intensity are lacking. This study aims to test whether a randomised controlled trial (RCT) of an intervention targeting young people living with depression is feasible by determining whether it is possible to recruit and retain young people, develop and deliver the intervention as planned, and evaluate training and delivery. METHODS The design is a three-arm cluster randomised controlled feasibility trial with embedded process evaluation. Participants will be help-seeking young people, aged 13-17 years experiencing mild to moderate low mood or depression, referred from three counties in England. The intervention will be delivered by registered exercise professionals, supported by mental health support workers, twice a week for 12 weeks. The three arms will be high-intensity exercise, low-intensity exercise, and a social activity control. All arms will receive a 'healthy living' behaviour change session prior to each exercise session and the two exercise groups are energy matched. The outcomes are referral, recruitment, and retention rates; attendance at exercise sessions; adherence to and ability to reach intensity during exercise sessions; proportions of missing data; adverse events, all measured at baseline, 3, and 6 months; resource use; and reach and representativeness. DISCUSSION UK National Health Service (NHS) policy is to provide young people with advice about using exercise to help depression but there is no evidence-based exercise intervention to either complement or as an alternative to medication or talking therapies. UK National Institute for Health and Care Excellence (NICE) guidelines suggest that exercise can be an effective treatment, but the evidence base is relatively weak. This feasibility trial will provide evidence about whether it is feasible to recruit and retain young people to a full RCT to assess the effectiveness and cost-effectiveness of an exercise intervention for depression. TRIAL REGISTRATION ISRCTN, ISRCTN66452702 . Registered 9 April 2020.
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Affiliation(s)
- N. Howlett
- Department of Psychology, Sport, and Geography, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - L. Bottoms
- Department of Psychology, Sport, and Geography, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - A. Chater
- Institute for Sport and Physical Activity Research (ISPAR), School of Sport Science and Physical Activity, Faculty of Health, Education, Sport and Social Science, University of Bedfordshire, Polhill Avenue, Bedford, MK41 9EA UK
| | - A. B. Clark
- Norwich Clinical Trials Unit, University of East Anglia, Norwich, Norfolk NR4 7TR UK
| | - T. Clarke
- Norfolk and Suffolk NHS Foundation Trust, Hellesdon Hospital, Drayton High Road, Norwich, NR6 5BE UK
- Norwich Medical School, University of East Anglia, Norwich, Norfolk NR4 7TJ UK
| | - L. David
- Centre for Health Services and Clinical Research, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - K. Irvine
- Department of Psychology, Sport, and Geography, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - A. Jones
- Norwich Medical School, University of East Anglia, Norwich, Norfolk NR4 7TJ UK
| | - J. Jones
- Centre for Research in Public Health and Community Care, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - S. E. Mengoni
- Department of Psychology, Sport, and Geography, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
- Centre for Health Services and Clinical Research, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - J. Murdoch
- Norwich Clinical Trials Unit, University of East Anglia, Norwich, Norfolk NR4 7TR UK
| | - M. Pond
- Norwich Clinical Trials Unit, University of East Anglia, Norwich, Norfolk NR4 7TR UK
| | - S. Sharma
- Department of Psychology, Sport, and Geography, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - E. J. Sims
- Norwich Clinical Trials Unit, University of East Anglia, Norwich, Norfolk NR4 7TR UK
| | - D. A. Turner
- Norwich Medical School, University of East Anglia, Norwich, Norfolk NR4 7TJ UK
| | - D. Wellsted
- Centre for Health Services and Clinical Research, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - J. Wilson
- Norfolk and Suffolk NHS Foundation Trust, Hellesdon Hospital, Drayton High Road, Norwich, NR6 5BE UK
- Norwich Medical School, University of East Anglia, Norwich, Norfolk NR4 7TJ UK
| | - S. Wyatt
- Centre for Health Services and Clinical Research, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
| | - D. Trivedi
- Centre for Research in Public Health and Community Care, University of Hertfordshire, College Lane, Hatfield, Herts AL10 9AB UK
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Alexandre L, Clark AB, Walton S, Lewis MP, Kumar B, Cheong EC, Warren H, Kadirkamanathan SS, Parsons SL, Dresner SM, Sims E, Jones M, Hammond M, Flather M, Loke YK, Swart AM, Hart AR. Adjuvant statin therapy for oesophageal adenocarcinoma: the STAT-ROC feasibility study. BJS Open 2019; 4:59-70. [PMID: 32011825 PMCID: PMC6996637 DOI: 10.1002/bjs5.50239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/22/2019] [Indexed: 01/14/2023] Open
Abstract
Background Statins inhibit proliferative signalling in oesophageal adenocarcinoma (OAC) and their use is associated with better survival in observational studies. The present study was undertaken to examine the feasibility of assessing adjuvant statin therapy in patients with operable OAC in a phase III RCT. Methods For this multicentre, double‐blind, parallel‐group, randomized, placebo‐controlled feasibility trial, adults with OAC (including Siewert I–II lesions) who had undergone oesophagectomy were centrally allocated (1 : 1) to simvastatin 40 mg or matching placebo by block randomization, stratified by centre. Participants, clinicians and investigators were blinded to treatment allocation. Patients received treatment for up to 1 year. Feasibility outcomes were recruitment, retention, drug absorption, adherence, safety, quality of life, generalizability and survival. Results A total of 120 patients were assessed for eligibility at four centres, of whom 32 (26·7 per cent) were randomized, 16 in each group. Seven patients withdrew. Participants allocated to simvastatin had lower low‐density lipoprotein cholesterol levels by 3 months (adjusted mean difference −0·83 (95 per cent c.i. −1·4 to −0·22) mmol/l; P = 0·009). Median adherence to medication was greater than 90 per cent between 3 and 12 months' follow‐up. Adverse events were similar between the groups. Quality‐of‐life data were complete for 98·3 per cent of questionnaire items. Cardiovascular disease, diabetes and aspirin use were more prevalent in the non‐randomized group, whereas tumour site, stage and grade were similar between groups. Survival estimates were imprecise. Conclusion This RCT supports the conduct and informs the design considerations for a future phase III trial of adjuvant statin therapy in patients with OAC. Registration number: ISRCTN98060456 (http://www.isrctn/com).
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Affiliation(s)
- L Alexandre
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - A B Clark
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - S Walton
- Cancer Research Team and, Norwich, UK
| | - M P Lewis
- Department of General Surgery, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, UK
| | - B Kumar
- Department of General Surgery, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, UK
| | - E C Cheong
- Department of General Surgery, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, UK
| | - H Warren
- Department of General Surgery, Queen Elizabeth Hospital, King's Lynn, UK
| | - S S Kadirkamanathan
- Department of General Surgery, Broomfield Hospital, Mid Essex Hospital Services NHS Trust, Chelmsford, UK
| | - S L Parsons
- Department of Surgery, Nottingham City Hospital, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - S M Dresner
- Department of General Surgery, James Cook University Hospital, Middlesbrough, UK
| | - E Sims
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - M Jones
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - M Hammond
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - M Flather
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - Y K Loke
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - A M Swart
- Norwich Medical School, University of East Anglia, Norwich, UK
| | - A R Hart
- Norwich Medical School, University of East Anglia, Norwich, UK
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Teh WH, Smith CJ, Barlas RS, Wood AD, Bettencourt-Silva JH, Clark AB, Metcalf AK, Bowles KM, Potter JF, Myint PK. Impact of stroke-associated pneumonia on mortality, length of hospitalization, and functional outcome. Acta Neurol Scand 2018; 138:293-300. [PMID: 29749062 DOI: 10.1111/ane.12956] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2018] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Stroke-associated pneumonia (SAP) is common and associated with adverse outcomes. Data on its impact beyond 1 year are scarce. MATERIALS AND METHODS This observational study was conducted in a cohort of stroke patients admitted consecutively to a tertiary referral center in the east of England, UK (January 2003-April 2015). Logistic regression models examined inpatient mortality and length of stay (LOS). Cox regression models examined longer-term mortality at predefined time periods (0-90 days, 90 days-1 year, 1-3 years, and 3-10 years) for SAP. Effect of SAP on functional outcome at discharge was assessed using logistic regression. RESULTS A total of 9238 patients (mean age [±SD] 77.61 ± 11.88 years) were included. SAP was diagnosed in 1083 (11.7%) patients. The majority of these cases (n = 658; 60.8%) were aspiration pneumonia. After controlling for age, sex, stroke type, Oxfordshire Community Stroke Project (OCSP) classification, prestroke modified Rankin scale, comorbidities, and acute illness markers, mortality estimates remained significant at 3 time periods: inpatient (OR 5.87, 95%CI [4.97-6.93]), 0-90 days (2.17 [1.97-2.40]), and 91-365 days (HR 1.31 [1.03-1.67]). SAP was also associated with higher odds of long LOS (OR 1.93 [1.67-2.22]) and worse functional outcome (OR 7.17 [5.44-9.45]). In this cohort, SAP did not increase mortality risk beyond 1 year post-stroke, but it was associated with reduced mortality beyond 3 years. CONCLUSIONS Stroke-associated pneumonia is not associated with increased long-term mortality, but it is linked with increased mortality up to 1 year, prolonged LOS, and poor functional outcome on discharge. Targeted intervention strategies are required to improve outcomes of SAP patients who survive to hospital discharge.
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Affiliation(s)
- W. H. Teh
- Institute of Applied Health Sciences; School of Medicine; Medical Sciences and Nutrition; University of Aberdeen; Aberdeen UK
| | - C. J. Smith
- Greater Manchester Comprehensive Stroke Centre; Manchester Academic Health Science Centre; Salford Royal NHS Foundation Trust; Salford UK
- Faculty of Biology; Medicine and Health; University of Manchester; Manchester UK
| | - R. S. Barlas
- Institute of Applied Health Sciences; School of Medicine; Medical Sciences and Nutrition; University of Aberdeen; Aberdeen UK
| | - A. D. Wood
- Institute of Applied Health Sciences; School of Medicine; Medical Sciences and Nutrition; University of Aberdeen; Aberdeen UK
| | - J. H. Bettencourt-Silva
- Institute of Applied Health Sciences; School of Medicine; Medical Sciences and Nutrition; University of Aberdeen; Aberdeen UK
- Stroke Research Group; Norwich Cardiovascular Research Group; Norwich Research Park; Norwich UK
| | - A. B. Clark
- Norwich Medical School; University of East Anglia; Norwich UK
| | - A. K. Metcalf
- Stroke Research Group; Norwich Cardiovascular Research Group; Norwich Research Park; Norwich UK
- Stroke Services; Norfolk and Norwich University Hospitals NHS Foundation Trust; Norwich UK
| | - K. M. Bowles
- Norwich Medical School; University of East Anglia; Norwich UK
- Stroke Research Group; Norwich Cardiovascular Research Group; Norwich Research Park; Norwich UK
| | - J. F. Potter
- Norwich Medical School; University of East Anglia; Norwich UK
- Stroke Research Group; Norwich Cardiovascular Research Group; Norwich Research Park; Norwich UK
| | - P. K. Myint
- Institute of Applied Health Sciences; School of Medicine; Medical Sciences and Nutrition; University of Aberdeen; Aberdeen UK
- Stroke Research Group; Norwich Cardiovascular Research Group; Norwich Research Park; Norwich UK
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Wood AD, Lorking N, Tiamkao S, Clark AB, Kongbunkiat K, Bettencourt-Silva JH, Sawanyawisuth K, Kasemsap N, Mamas MA, Myint PK. 78WINTER EXCESS IN HOSPITAL ADMISSIONS, IN-PATIENT MORTALITY, AND COMPLICATIONS IN STROKE: A THAILAND NATIONAL DATABASE STUDY. Age Ageing 2018. [DOI: 10.1093/ageing/afy135.03] [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: 11/13/2022] Open
Affiliation(s)
- A D Wood
- ACER, University of Aberdeen, UK
| | | | - S Tiamkao
- Department of Medicine, Khon Kaen University, Thailand
| | - A B Clark
- Norwich Medical School, University of East Anglia, UK
| | - K Kongbunkiat
- Department of Medicine, Khon Kaen University, Thailand
| | | | | | - N Kasemsap
- Department of Medicine, Khon Kaen University, Thailand
| | - M A Mamas
- Cardiovascular Research Group, Keele University, UK
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Clark AB, Tokach MD, DeRouchey JM, Dritz SS, Goodband RD, Woodworth JC, Touchette KJ, Bello NM. Modeling the effects of standardized ileal digestible isoleucine to lysine ratio on growth performance of nursery pigs . Transl Anim Sci 2017; 1:437-447. [PMID: 32704667 PMCID: PMC7204974 DOI: 10.2527/tas2017.0048] [Citation(s) in RCA: 5] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/03/2017] [Indexed: 12/27/2022] Open
Abstract
Two experiments evaluated the effects of increasing standardized ileal digestible (SID) Ile:Lys ratio on growth performance of nursery pigs. In both experiments, dietary treatments consisted of 40, 44, 48, 52, 54, 58, or 63% SID Ile:Lys ratio. Diets were formulated using analyzed ingredient AA values and NRC (2012) SID coefficients. A combination of field peas and spray dried blood cells were used to ensure a low enough Ile diet concentration while minimizing the excess of Leu. The experiments consisted of 8 pens per dietary treatment with 5 pigs per pen for a total of 280 nursery pigs per experiment (Exp. 1: PIC 327 × 1,050, initially 6.7 ± 1.0 kg BW; Exp. 2: DNA 600 × 241, initially 6.0 ± 0.97 kg BW). Data were analyzed using mixed models with heterogeneous variance, where appropriate. The dose response was further characterized using quadratic polynomial (QP), broken-line linear (BLL), or broken-line quadratic (BLQ) functional forms. For Exp. 1, diets were initiated 6-d post-weaning and fed for 12-d followed by a common diet from d 12 to 28. From d 0 to 12, increasing dietary SID Ile:Lys ratio increased ADG (linear, P < 0.005) and ADFI (quadratic, P < 0.017) but G:F decreased (quadratic, P < 0.043). For ADG, the QP, BLL, and BLQ models resulted in maximum ADG at 64.7, 52.0, and 52.0 SID Ile:Lys ratios, respectively. For ADFI, the BLL breakpoint occurred at 50.6 and the QP predicted maximum ADFI at 56.2 SID Ile:Lys ratio. In Exp. 2, diets were initiated 6-d post-weaning for 7 pens and 3-d post-weaning for one heavier block and fed for 18-d followed by a common diet from d 18 to 32. From d 0 to 18, ADG and ADFI increased (quadratic, P < 0.016) with no evidence for difference in G:F as SID Ile:Lys ratio increased. For ADG, the QP and BLL had similar fit with breakpoints or maximums occurring at 58.3 and 51.8% SID Ile:Lys ratio, respectively. For ADFI, the BLQ breakpoint occurred at 52.0 SID Ile:Lys and the QP maximum ADFI at 57.2% SID Ile:Lys ratio. In conclusion, broken-line models reported maxima of 52.0% Ile:Lys ratio while quadratic models were as high as 64% of Lys to maximize ADG and ADFI of 6- to 11-kg nursery pigs. However, for the QP models 99% of the maximum response was achieved with a dose comparable to that from the broken line models. Therefore, these results are similar to the NRC (2012) requirement estimate of 51.1 Ile:Lys ratio.
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Affiliation(s)
- A B Clark
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - M D Tokach
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - J M DeRouchey
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - S S Dritz
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506
| | - R D Goodband
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - J C Woodworth
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | | | - N M Bello
- Department of Statistics, College of Arts and Sciences, Kansas State University, Manhattan 66506
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Clark AB, Tokach MD, DeRouchey JM, Dritz SS, Goodband RD, Woodworth JC, Touchette KJ, Bello NM. Modeling the effects of standardized ileal digestible valine to lysine ratio on growth performance of nursery pigs . Transl Anim Sci 2017; 1:448-457. [PMID: 32704668 PMCID: PMC7204984 DOI: 10.2527/tas2017.0049] [Citation(s) in RCA: 9] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/05/2017] [Indexed: 11/25/2022] Open
Abstract
Two experiments evaluated the effects of increasing Lys and Val on growth performance of nursery pigs. In Exp. 1,300 nursery pigs (PIC 327 × 1,050, initially 6.7 ± 1.4 kg BW) were randomly allotted to 1 of 6 diets containing 1.10, 1.20, 1.30, 1.40, 1.50, or 1.60% standardized ileal digestible (SID) Lys, with 10 pens per dietary treatment and 5 pigs per pen. Linear and nonlinear mixed models were fitted to estimate dose responses. From d 0 to 14, and for the overall 28 d period, ADG and G:F increased (linear, P < 0.001) as SID Lys increased, with no evidence of differences in ADFI. Dose response modeling indicated the SID Lys requirement for ADG and G:F was at 1.45% using a broken line linear (BLL) and greater than 1.60% using a quadratic polynomial (QP) model. In Exp. 2, 280 nursery pigs (PIC 327 × 1,050, initially 6.5 ± 1.3 kg BW) were allotted to 1 of 7 diets containing SID Val:Lys ratios of 50, 57, 63, 68, 73, 78, or 85%. The dietary SID Lys concentration 1.24% SID Lys which was below the estimated requirement from Exp. 1 and ensured the Val:Lys ratio was not underestimated. From d 0 to 14, ADG, ADFI, and G:F increased (quadratic, P < 0.039) with increasing SID Val:Lys. For ADG, the best fitting model was a BLL, with a breakpoint estimate of 62.9% SID Val:Lys [52.2, 73.7] ratio while for G:F the best fit model was a quadratic polynomial with a maximum G:F at 71.7% SID Val:Lys (95%CI:[58, > 85]). Average daily feed intake was also modeled with a quadratic polynomial and maximized at 73.7% Val:Lys (95% CI: [61, > 85]). In conclusion, the Val requirement ranged from approximately 63 to 74% of Lys depending on the response criteria modeled.
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Affiliation(s)
- A B Clark
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - M D Tokach
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - J M DeRouchey
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - S S Dritz
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506
| | - R D Goodband
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | - J C Woodworth
- Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan 66506
| | | | - N M Bello
- Department of Statistics, College of Arts and Sciences, Kansas State University, Manhattan 66506
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Foster EJ, Barlas RS, Clark AB, Bettencourt-Silva JH, Bowles KM, Metcalf AK, Potter JF, Myint PK. 35DETERMINANTS OF POST-DISCHARGE FALLS AND FRACTURES AFTER STROKE OVER LONG TERM FOLLOW UP. Age Ageing 2017. [DOI: 10.1093/ageing/afx110.35] [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: 11/14/2022] Open
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Adekunle-Olarinde IR, McCall SJ, Barlas RS, Wood AD, Clark AB, Bettencourt-Silva JH, Metcalf AK, Bowles KM, Soiza RL, Potter JF, Myint PK. Addition of sodium criterion to SOAR stroke score. Acta Neurol Scand 2017; 135:553-559. [PMID: 27397108 DOI: 10.1111/ane.12634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2016] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To examine the usefulness of including sodium (Na) levels as a criterion to the SOAR stroke score in predicting inpatient and 7-day mortality in stroke. MATERIALS AND METHODS Data from the Norfolk and Norwich University Hospital Stroke & TIA register (2003-2015) were analysed. Univariate and then multivariate models controlling for SOAR variables were used to assess the association between admission sodium levels and inpatient and 7-day mortality. The prognostic ability of the SOAR and SOAR Na scores for mortality outcomes at both time points were then compared using the Area Under the Curve (AUC) values from the Receiver Operating Characteristic curves. RESULTS A total of 8493 cases were included (male=47.4%, mean (SD) 77.7 (11.6) years). Compared with normonatremia (135-145 mmol/L), hypernatraemia (>145 mmol/L) was associated with inpatient mortality and moderate (125-129 mmol/L) and severe hypontraemia (<125 mmol/L) with 7-day mortality after adjustment for stroke type, Oxfordshire Community Stroke Project classification, age, prestroke modified Rankin score and sex. The SOAR and SOAR-Na scores both performed well in predicting inpatient mortality with AUC values of .794 (.78-.81) and .796 (.78-.81), respectively. 7-day mortality showed similar results. Both scores were less predictive in those with chronic kidney disease (CKD) and more so in those with hypoglycaemia. CONCLUSION The SOAR-Na did not perform considerably better than the SOAR stroke score. However, the performance of SOAR-Na in those with CKD and dysglycaemias requires further investigation.
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Affiliation(s)
- I. R. Adekunle-Olarinde
- Epidemiology Group; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
| | - S. J. McCall
- Epidemiology Group; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
- Nuffield Department of Population Health; University of Oxford; Oxford UK
| | - R. S. Barlas
- Epidemiology Group; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
| | - A. D. Wood
- Epidemiology Group; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
| | - A. B. Clark
- Norwich Medical School; University of East Anglia; Norwich UK
| | - J. H. Bettencourt-Silva
- Clinical Informatics; Department of Medicine; University of Cambridge; Cambridge UK
- Norfolk and Norwich University Hospital; Norwich UK
| | | | - K. M. Bowles
- Norwich Medical School; University of East Anglia; Norwich UK
- Norfolk and Norwich University Hospital; Norwich UK
| | - R. L. Soiza
- Health Services Research Unit; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
- Academic Department of Medicine for the Elderly; Aberdeen Royal Infirmary; NHS Grampian; Aberdeen UK
| | - J. F. Potter
- Norwich Medical School; University of East Anglia; Norwich UK
- Norfolk and Norwich University Hospital; Norwich UK
| | - P. K. Myint
- Epidemiology Group; Institute of Applied Health Sciences; University of Aberdeen; Aberdeen UK
- Academic Department of Medicine for the Elderly; Aberdeen Royal Infirmary; NHS Grampian; Aberdeen UK
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Clark AB, Tokach MD, DeRouchey JM, Dritz SS, Woodworth JC, Goodband RD, Touchette KJ, Allerson M. 174 Effects of dietary lysine level and amino acid ratios on nursery pig performance. J Anim Sci 2017. [DOI: 10.2527/asasmw.2017.12.174] [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: 11/13/2022] Open
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Shawk DJ, Moniz MM, Goodband RD, DeRouchey JM, Tokach MD, Woodworth JC, Dritz SS, Clark AB, Williams HE. 222 Effects of dietary salt concentration on performance of 7 to 10 Kg nursery pigs. J Anim Sci 2017. [DOI: 10.2527/asasmw.2017.12.222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Clark AB, Tokach MD, DeRouchey JM, Dritz SS, Touchette KJ, Goodband RD, Woodworth JC. 230 Effects of dietary standardized ileal digestible Ile:Lys ratio on growth performance of 6 to 11 Kg pigs. J Anim Sci 2017. [DOI: 10.2527/asasmw.2017.12.230] [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: 11/13/2022] Open
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Landero JL, Young MG, Touchette KJ, Stevenson MJ, Clark AB, Gonçalves MAD, Dritz SS. 201 Lysine requirement titration for barrows and gilts from 25- to 75-kg. J Anim Sci 2016. [DOI: 10.2527/msasas2016-201] [Citation(s) in RCA: 3] [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] Open
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Clark AB, De Jong JA, DeRouchey JM, Tokach MD, Dritz SS, Goodband RD, Woodworth JC. 213 Effects of creep feed pellet diameter on suckling and nursery pig performance. J Anim Sci 2016. [DOI: 10.2527/msasas2016-213] [Citation(s) in RCA: 3] [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] Open
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Clark AB, Tokach MD, Dritz SS, Touchette KJ, GonÁalves MAD, DeRouchey JM, Goodband RD, Woodworth JC. 097 Effects of standardized ileal digestible valine:lysine ratio on nursery pig performance. J Anim Sci 2016. [DOI: 10.2527/msasas2016-097] [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: 11/13/2022] Open
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15
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Mannu GS, Kyu MM, Bettencourt-Silva JH, Loke YK, Clark AB, Metcalf AK, Potter JF, Myint PK. Age but not ABCD(2) score predicts any level of carotid stenosis in either symptomatic or asymptomatic side in transient ischaemic attack. Int J Clin Pract 2015; 69:948-56. [PMID: 25832133 DOI: 10.1111/ijcp.12637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [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: 11/26/2022] Open
Abstract
BACKGROUND The ABCD(2) score is routinely used in assessment of transient ischaemic attack (TIA) to assess the risk of developing stroke. There remains uncertainty regarding whether the ABCD(2) score could be used to help predict extent of carotid artery stenosis (CAS). OBJECTIVES We aimed to (i) collate and analyse all available published literature on this topic and (ii) compare the data from our local population to the existing evidence base. MATERIALS AND METHODS We conducted a retrospective-observational study over a 6-month period using our East of England hospital-based TIA clinic data with a catchment population of ~750,000. We also searched the literature on studies reporting the association between ABCD(2) score and CAS. RESULTS We included 341 patients in our observational study. The mean age in our cohort was 72.86 years (SD 10.91) with 52% male participants. ABCD(2) score was not significantly associated with CAS (p = 0.78). Only age > 60 years was significantly associated with ipsilateral (> 50%) and contralateral CAS (> 50% and > 70%) (p < 0.01) after controlling for other confounders. The systematic review identified four studies for inclusion and no significant association between ABCD(2) score and CAS was reported, confirming our findings. CONCLUSION Our systematic review and observational study confirm that the ABCD(2) score does not predict CAS. However, our observational study has examined a larger number of possible predictors and demonstrates that age appears to be the single best predictor of CAS in patients presenting with a TIA. Selection of urgent carotid ultrasound scan thus should be based on individual patient's age and potential benefit of carotid intervention rather than ABCD(2) score.
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Affiliation(s)
- G S Mannu
- Oxford University Hospitals NHS Trust, Oxford, UK
- Norfolk and Norwich University Hospital, Norfolk, UK
| | - M M Kyu
- Norfolk and Norwich University Hospital, Norfolk, UK
- Huddersfield Royal Infirmary, West Yorkshire, UK
| | - J H Bettencourt-Silva
- Norfolk and Norwich University Hospital, Norfolk, UK
- University of East Anglia, Norwich, UK
| | - Y K Loke
- Norfolk and Norwich University Hospital, Norfolk, UK
- University of East Anglia, Norwich, UK
| | - A B Clark
- University of East Anglia, Norwich, UK
| | - A K Metcalf
- Norfolk and Norwich University Hospital, Norfolk, UK
- University of East Anglia, Norwich, UK
| | - J F Potter
- Norfolk and Norwich University Hospital, Norfolk, UK
- University of East Anglia, Norwich, UK
| | - P K Myint
- University of Aberdeen, Aberdeen, UK
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16
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Kwok CS, Clark AB, Musgrave SD, Potter JF, Dalton G, Day DJ, George A, Metcalf AK, Ngeh J, Nicolson A, Owusu-Agyei P, Shekhar R, Walsh K, Warburton EA, Bachmann MO, Myint PK. The SOAR stroke score predicts hospital length of stay in acute stroke: an external validation study. Int J Clin Pract 2015; 69:659-65. [PMID: 25648886 DOI: 10.1111/ijcp.12577] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
AIMS The objective of this study is to externally validate the SOAR stroke score (Stroke subtype, Oxfordshire Community Stroke Project Classification, Age and prestroke modified Rankin score) in predicting hospital length of stay (LOS) following an admission for acute stroke. METHODS We conducted a multi-centre observational study in eight National Health Service hospital trusts in the Anglia Stroke & Heart Clinical Network between September 2008 and April 2011. The usefulness of the SOAR stroke score in predicting hospital LOS in the acute settings was examined for all stroke and then stratified by discharge status (discharged alive or died during the admission). RESULTS A total of 3596 patients (mean age 77 years) with first-ever or recurrent stroke (92% ischaemic) were included. Increasing LOS was observed with increasing SOAR stroke score (p < 0.001 for both mean and median) and the SOAR stroke score of 0 had the shortest mean LOS (12 ± 20 days) while the SOAR stroke score of 6 had the longest mean LOS (26 ± 28 days). Among patients who were discharged alive, increasing SOAR stroke score had a significantly higher mean and median LOS (p < 0.001 for both mean and median) and the LOS peaked among patients with score value of 6 [mean (SD) 35 ± 31 days, median (IQR) 23 (14-48) days]. For patients who died as in-patient, there was no significant difference in mean or median LOS with increasing SOAR stroke score (p = 0.68 and p = 0.79, respectively). CONCLUSION This external validation study confirms the usefulness of the SOAR stroke score in predicting LOS in patients with acute stroke especially in those who are likely to survive to discharge. This provides a simple prognostic score useful for clinicians, patients and service providers.
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Affiliation(s)
- C S Kwok
- Institute of Applied Health Sciences, School of Medicine & Dentistry, University of Aberdeen, Aberdeen, UK
- University of Manchester, Manchester, UK
| | | | | | - J F Potter
- Norwich Medical School, Norwich, UK
- Norfolk and Norwich University Hospital, Norwich, UK
| | - G Dalton
- Anglia Stroke & Heart Clinical Network, Cambridge, UK
| | - D J Day
- Addenbrooke's Hospital, Cambridge, UK
| | - A George
- James Paget University Hospital, Gorleston, UK
| | - A K Metcalf
- Norwich Medical School, Norwich, UK
- Norfolk and Norwich University Hospital, Norwich, UK
| | - J Ngeh
- Colchester Hospital, Colchester, UK
| | - A Nicolson
- West Suffolk Hospital, Bury St Edmunds, UK
| | | | - R Shekhar
- Queen Elizabeth Hospital, Kings Lynn, UK
| | - K Walsh
- Hinchingbrooke Hospital, Huntingdon, UK
| | | | | | - P K Myint
- Institute of Applied Health Sciences, School of Medicine & Dentistry, University of Aberdeen, Aberdeen, UK
- Norwich Medical School, Norwich, UK
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17
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Daley DJ, Deane KHO, Gray RJ, Clark AB, Pfeil M, Sabanathan K, Worth PF, Myint PK. Adherence therapy improves medication adherence and quality of life in people with Parkinson's disease: a randomised controlled trial. Int J Clin Pract 2014; 68:963-71. [PMID: 24750544 DOI: 10.1111/ijcp.12439] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [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: 12/01/2022] Open
Abstract
BACKGROUND Many factors are associated with medication non-adherence in Parkinson's disease (PD), including complex treatment regimens, mood disorders and impaired cognition. However, interventions to improve adherence which acknowledge such factors are lacking. A phase II randomised controlled trial was conducted investigating whether Adherence Therapy (AT) improves medication adherence and quality of life (QoL) compared with routine care (RC) in PD. METHODS Eligible PD patients and their spouse/carers were randomised to intervention (RC plus AT) or control (RC alone). Primary outcomes were change in adherence (Morisky Medication Adherence Scale) and QoL (Parkinson's Disease Questionnaire-39) from baseline to week-12 follow up. Secondary outcomes were MDS-UPDRS (part I, II, IV), Beliefs about Medication Questionnaire (BMQ), EuroQol (EQ-5D) and the Caregiving Distress Scale. Blinded data were analysed using logistic and linear regression models based on the intention-to-treat principle. RESULTS Seventy-six patients and 46 spouse/carers completed the study (intervention: n = 38 patients, n = 24 spouse/carers). At week-12 AT significantly improved adherence compared with RC (OR 8.2; 95% CI: 2.8, 24.3). Numbers needed to treat (NNT) were 2.2 (CI: 1.6, 3.9). Compared with RC, AT significantly improved PDQ-39 (-9.0 CI: -12.2, -5.8), BMQ general harm (-1.0 CI: -1.9, -0.2) and MDS-UPDRS part II (-4.8 CI: -8.1, -1.4). No significant interaction was observed between the presence of a spouse/carer and the effect of AT. CONCLUSION Adherence Therapy improved self-reported adherence and QoL in a PD sample. The small NNT suggests AT may be cost-effective. A larger pragmatic trial to test the efficacy and cost-effectiveness of AT by multiple therapists is required.
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Affiliation(s)
- D J Daley
- Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK; Norfolk & Norwich University Hospital NHS Foundation Trust, Norwich, UK
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18
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Clark AB. Scent marks as social signals inGalago crassicaudatus II. Discrimination between individuals by scent. J Chem Ecol 2014; 8:1153-65. [PMID: 24413909 DOI: 10.1007/bf00986985] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/1981] [Revised: 01/22/1982] [Indexed: 11/25/2022]
Abstract
Thick-tailed galagos,Galago crassicaudatus argentatus, which had been habituated to the scent marks of a conspecific through repeated presentations, increased their sniffing when presented with scent marks from a second conspecific of the same sex. Thus, they discriminated between the scents of individual conspecifics. This result was obtained using naturally scent-marked perches and perches carrying only chest gland scent-the latter even two weeks after the marking. When urine, the prevalent scent signal among most other galago species, was tested, it elicited little interest and discriminations were not clearly made. It is suggested that the use of more specialized scents is related to the social characteristics ofGalago crassicaudatus.
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Affiliation(s)
- A B Clark
- Kellogg Biological Station, 49060, Hickory Corners, Michigan
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19
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Abstract
The shy-bold continuum is a fundamental axis of behavioral variation in humans and at least some other species, but its taxonomic distribution and evolutionary implications are unknown. Models of optimal risk, density- or frequency-dependent selection, and phenotypic plasticity can provide a theoretical framework for understanding shyness and boldness as a product of natural selection. We sketch this framework and review the few empirical studies of shyness and boldness in natural populations. The study of shyness and boldness adds an interesting new dimension to behavioral ecology by focusing on the nature of continuous behavioral variation that exists within the familiar categories of age, sex and size.
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Affiliation(s)
- D Sloan Wilson
- Dept of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
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20
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Alexandre L, Clark AB, Cheong E, Lewis MPN, Hart AR. Systematic review: potential preventive effects of statins against oesophageal adenocarcinoma. Aliment Pharmacol Ther 2012; 36:301-11. [PMID: 22716127 DOI: 10.1111/j.1365-2036.2012.05194.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 02/21/2012] [Accepted: 06/04/2012] [Indexed: 12/14/2022]
Abstract
BACKGROUND The incidence of oesophageal adenocarcinoma (OAC) has risen dramatically in recent decades, and its prognosis remains extremely poor. There is emerging evidence that statins may prevent OAC. AIM To systematically review both the experimental and epidemiological evidence to determine whether statins reduce the risk of developing OAC. METHODS Relevant laboratory and epidemiological studies were identified by systematically searching the PUBMED and EMBASE electronic databases for data on statins and oesophageal cancer (OC). The evidence was assessed according to the nine Bradford Hill criteria (BHC) of causality. Pooled effect sizes (ES) were calculated for the risk of OC with prior statin use. RESULTS Many of the BHC were supported including: 'plausible biological mechanisms', 'coherence', 'strong associations', 'consistency', 'biological gradient', 'analogy' and 'temporality'. Three experimental studies reported that statins inhibited proliferation, induced apoptosis and may limit metastatic potential in OAC cell lines. Fixed effects meta-analysis of two prospective studies in Barrett's oesophagus cohorts, involving 1382 participants, showed an ES of 0.53 (95% CI = 0.36-0.78, P = 0.001, I(2) = 0%) for risk of OAC with prior statin use. Meta-analysis of three prospective studies in general population cohorts, involving 35 214 participants, showed an ES of 0.86 (95% CI = 0.78-0.94, P = 0.001, I(2) = 0%) for risk of OC with prior statin use. The most important criterion, 'experiment', is as yet unfulfilled as to date there are no clinical trials which investigate this hypothesis. CONCLUSION There is some evidence that statins may protect against the development of OAC, although to be conclusive, data from randomised clinical trials are required.
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Affiliation(s)
- L Alexandre
- Norwich Medical School, University of East Anglia, Norwich, UK.
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21
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22
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DeCarlo CH, Clark AB, McGowan KJ, Ziegler PE, Glaser AL, Szonyi B, Mohammed HO. Factors associated with the risk of West Nile virus among crows in New York State. Zoonoses Public Health 2010; 58:270-5. [PMID: 20707862 DOI: 10.1111/j.1863-2378.2010.01346.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
West Nile virus (WNV) is transmitted between avian hosts in enzootic cycles by a mosquito vector. The virus has significant disease effects on humans and equines when it bridges into an epizootic cycle. As the initial epidemic of WNV in 1999, perennial outbreaks in New York State suggest the local establishment of natural foci with perpetuation of the virus among susceptible hosts rather than reintroduction of the virus. The factors that play a role in the perpetuation of the virus are not fully understood. American crows (Corvus brachyrhynchos) are known to be highly susceptible to infection with the virus. We investigate the factors that put crows at risk of infection in Tompkins County, New York during the period of 2000-2008 in a case-control study. Cases were crow carcasses that were found dead and tested positive for WNV using real time reverse transcription or VecTest. Data on putative risk factors were collected and assessed for significance of association with the presence of WNV using logistic regression analysis to evaluate the significance of each factor while simultaneously controlling for the effect of others. The risk of a crow carcass testing WNV positive varied with age, season of the year and ecological area where the carcass was found. Crows that were more than 1-year-old were four times more likely to be WNV positive in comparison to birds that were less than 1 year of age. It was three times more likely to find WNV positive carcasses in residential areas in comparison to rural areas. The risk of testing WNV positive did not vary by sex of the crow carcasses.
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Affiliation(s)
- C H DeCarlo
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-5786, USA
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23
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Abstract
1. The reality of a chemical cycle proposed to describe the rhodopsin system is tested with dark adaptation measurements. 2. The first few minutes of rod dark adaptation are rapid following short, slower following long irradiation. As dark adaptation proceeds, the slow process grows more prominent, and occupies completely the final stages of adaptation. 3. Light adaptation displays similar duality. As the exposure to light of constant intensity lengthens, the visual threshold rises, and independently the speed of dark adaptation decreases. 4. These results conform with predictions from the chemical equations.
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Affiliation(s)
- G Wald
- Biological Laboratories, Harvard University, Cambridge
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24
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Clark AB. More Than Kin and Less Than Kind. The Evolution of Family Conflict Douglas W. Mock. Integr Comp Biol 2007. [DOI: 10.1093/icb/icm102] [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: 11/14/2022] Open
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26
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Raistrick H, Clark AB. Studies on the Cycloclastic Power of Bacteria: Part II. A Quantitative Study of the Aerobic Decomposition of Tryptophan and Tyrosine by Bacteria. Biochem J 2006; 15:76-82. [PMID: 16742977 PMCID: PMC1258959 DOI: 10.1042/bj0150076] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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28
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Affiliation(s)
- C P Winsor
- Biological Laboratories, Harvard University
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29
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Bennett AMD, Clark AB, Bath AP, Montgomery PQ. Meta-analysis of the timing of haemorrhage after tonsillectomy: an important factor in determining the safety of performing tonsillectomy as a day case procedure. Clin Otolaryngol 2005; 30:418-23. [PMID: 16232245 DOI: 10.1111/j.1365-2273.2005.01060.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [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: 11/30/2022]
Abstract
OBJECTIVES To perform a meta-analysis of studies of the timing of primary tonsillectomy haemorrhage. In particular to compare the difference in risk between 0-8 and 8-24 h; that is whether overnight inpatient tonsillectomy is required. DESIGN Medline search of all tonsillectomy studies to perform a meta-analysis of the timing of primary haemorrhages. SETTING Literature-based study. PARTICIPANTS All adult and paediatric tonsillectomy studies giving the absolute number and timing of all primary haemorrhages. MAIN OUTCOME MEASURES The overall incidence of haemorrhage occurring between 0-8 and 8-24 h. The overall incidence of haemorrhage for each of the first 24 h after operation. Compare risk of a bleed occurring 0-8, 8-24 and >24 h where data were available. RESULTS From a 1.4% overall risk of a primary haemorrhage only one in 14 occur after 8 h, i.e. 0.1% (95% CI=0.08-0.16%). A total of 833 patients would require to be kept overnight in order to identify one case of bleeding after 8 h. CONCLUSIONS Little benefit was conferred from overnight admission from the point of view of monitoring for primary haemorrhage. A case can be made for either day-case tonsillectomy (hospital stay over the period in which 93% of primary haemorrhages would occur) or the 'belt-and-braces' approach of a 1-week stay (during which all haemorrhages would occur) but current 24-h admission appears illogical.
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Affiliation(s)
- A M D Bennett
- Department of ENT, Norfolk and Norwich University Hospital, Norwich, UK.
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30
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Abstract
In bladder cancer the observed microsatellite instability indicates that mismatch repair deficiency could be a frequently involved factor in bladder cancer progression. To investigate this hypothesis we analysed extracts of seven bladder cancer cell lines and, as a novel approach, five clinical cancer samples for mismatch repair activity. We found that one cell line (T24) and three of the clinical samples had a reduced repair capacity, measured to approximately 20% or less. The T24 cell extract was unable to repair a G-G mismatch and showed reduced repair of a 2-base loop, consistent with diminished function of the MSH2-MSH6 heterodimer. The functional assay was combined with measurement for mutation frequency, microsatellite analysis, sequencing, MTT assay, immunohistochemical analysis and RT-PCR analysis of the mismatch repair genes MSH2, MSH3, MSH6, PMS1, PMS2 and MLH1. A >7-fold relative increase in mutation frequency was observed for T24 compared to a bladder cancer cell line with a fully functional mismatch repair system. Neither microsatellite instability, loss of repair nor mismatch repair gene mutations were detected. However, RT-PCR analysis of mRNA levels did detect changes in the ratio of expression of the Mut S and Mut L homologues. The T24 cell line had the lowest MSH6 expression level of the cell lines tested. Identical RT-PCR analysis of seventeen clinical samples (normal urothelium, 7; pTa low stage, 5; and pT1-4 high stage, 5) indicated a significant change in the expression ratio between MSH3/MSH6 (P< 0.004), MSH2/MSH3 (P< 0.012) and PMS2/MLH1 P< 0.005, in high stage bladder tumours compared to normal urothelium and low stage tumours. Collectively, the data suggest that imbalanced expression of mismatch repair genes could lead to partial loss of mismatch repair activity that is associated with invasive bladder cancer.
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Affiliation(s)
- T Thykjaer
- Department of Clinical Biochemistry, Skejby University Hospital, 8200 Aarhus N, Denmark
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31
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Clark AB, Valle F, Drotschmann K, Gary RK, Kunkel TA. Functional interaction of proliferating cell nuclear antigen with MSH2-MSH6 and MSH2-MSH3 complexes. J Biol Chem 2000; 275:36498-501. [PMID: 11005803 DOI: 10.1074/jbc.c000513200] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic DNA mismatch repair requires the concerted action of several proteins, including proliferating cell nuclear antigen (PCNA) and heterodimers of MSH2 complexed with either MSH3 or MSH6. Here we report that MSH3 and MSH6, but not MSH2, contain N-terminal sequence motifs characteristic of proteins that bind to PCNA. MSH3 and MSH6 peptides containing these motifs bound PCNA, as did the intact Msh2-Msh6 complex. This binding was strongly reduced when alanine was substituted for conserved residues in the motif. Yeast strains containing alanine substitutions in the PCNA binding motif of Msh6 or Msh3 had elevated mutation rates, indicating that these interactions are important for genome stability. When human MSH3 or MSH6 peptides containing the PCNA binding motif were added to a human cell extract, mismatch repair activity was inhibited at a step preceding DNA resynthesis. Thus, MSH3 and MSH6 interactions with PCNA may facilitate early steps in DNA mismatch repair and may also be important for other roles of these eukaryotic MutS homologs.
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Affiliation(s)
- A B Clark
- Laboratory of Molecular Genetics and Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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32
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Abstract
Hereditary non-polyposis colorectal cancer (HNPCC) is associated with germline mutations in the DNA mismatch repair gene hMSH2 [1], the human homologue of the Escherichia coli MutS gene. These are mostly nonsense, frameshift or deletion mutations that result in loss of intact protein and complete inactivation of DNA mismatch repair. However, cancer is also associated with hMSH2 missense mutations that are merely inferred to be deleterious because they result in non-conservative substitutions of amino acids that are highly conserved among MutS family proteins. Moreover, sequence polymorphisms exist in hMSH2 that also change conserved amino acids but whose functional consequences and relationship to cancer are uncertain. Here, we show that yeast strains harboring putative equivalents of three hMSH2 polymorphisms have elevated mutation rates. Mutator effects were also observed for yeast equivalents of hMSH2 missense mutations found in HNPCC families and in an early onset colon tumor. Several distinct phenotypes were observed, indicating that these missense mutations have differential effects on MSH2 function(s). The results suggest that cancer may be associated with even partial loss of hMSH2 function and they are consistent with the hypothesis that polymorphisms in hMSH2 might predispose humans to disease.
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Affiliation(s)
- K Drotschmann
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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Drotschmann K, Clark AB, Tran HT, Resnick MA, Gordenin DA, Kunkel TA. Mutator phenotypes of yeast strains heterozygous for mutations in the MSH2 gene. Proc Natl Acad Sci U S A 1999; 96:2970-5. [PMID: 10077621 PMCID: PMC15879 DOI: 10.1073/pnas.96.6.2970] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [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] [Indexed: 11/18/2022] Open
Abstract
Heterozygosity for germ-line mutations in the DNA mismatch repair gene MSH2 predisposes humans to cancer. Here we use a highly sensitive reporter to describe a spontaneous mutator phenotype in diploid yeast cells containing a deletion of only one MSH2 allele. We also identify five MSH2 missense mutations that have dominant mutator effects in heterozygous cells when expressed at normal levels from the natural MSH2 promoter. For example, a 230-fold mutator effect is observed in an MSH2/msh2 diploid strain in which Gly693, which is invariant in MutS homologs and involved in ATP hydrolysis, is changed to alanine. DNA binding data suggest that mismatch repair is suppressed by binding of a mutant Msh2-Msh6 heterodimer to a mismatch with subsequent inability to dissociate from the mismatch in the presence of ATP. A dominant mutator effect also is observed in yeast when Gly693 is changed to serine. An early onset colorectal tumor is heterozygous for the analogous Gly --> Ser mutation in hMSH2, and a second hMSH2 mutation was not found, suggesting that this missense mutation may predispose to cancer via a dominant mutator effect. The mutator effects of the deletion mutant and the Gly --> Ala missense mutant in yeast MSH2 are enhanced by heterozygosity for a missense mutation in DNA polymerase delta that reduces its proofreading activity but is not a mutator in the heterozygous state. The synergistic effects of heterozygosity for mutations in two different genes that act in series to correct replication errors may be relevant to cancer predisposition.
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Affiliation(s)
- K Drotschmann
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709, USA
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Clark AB, Cook ME, Tran HT, Gordenin DA, Resnick MA, Kunkel TA. Functional analysis of human MutSalpha and MutSbeta complexes in yeast. Nucleic Acids Res 1999; 27:736-42. [PMID: 9889267 PMCID: PMC148241 DOI: 10.1093/nar/27.3.736] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [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: 11/15/2022] Open
Abstract
Mismatch repair (MMR) is initiated when a heterodimer of hMSH2*hMSH6 or hMSH2*hMSH3 binds to mismatches. Here we perform functional analyses of these human protein complexes in yeast. We use a sensitive genetic system wherein the rate of single-base deletions in a homopolymeric run in the LYS2 gene is 10 000-fold higher in an msh2 mutant than in a wild-type strain. Expression of the human proteins alone or in combination does not reduce the mutation rate of the msh2 strain, and expression of the individual human proteins does not increase the low mutation rate of a wild-type strain. However, co-expression of hMSH2 and hMSH6 in wild-type yeast increases the mutation rate 4000-fold, while co-expression of hMSH2 and hMSH3 elevates the rate 5-fold. Analysis of cell extracts indicates that the proteins are expressed and bind to mismatched DNA. The results suggest that hMutSalpha and hMutSbeta complexes form, bind to and prevent correction of replication slippage errors in yeast. Expression of hMSH6 with hMSH2 containing a proline substituted for a conserved Arg524 eliminates the mutator effect and reduces mismatch binding. The analogous mutation in humans is associated with microsatellite instability, defective MMR and cancer, illustrating the utility of the yeast system for studying human disease alleles.
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Affiliation(s)
- A B Clark
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, PO Box 12233,Research Triangle Park, NC 27709, USA
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35
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Abstract
The begging behaviour of nestling birds appears to be the main signal telling parents how much food is needed by the brood. Not only may the accuracy of that information be reduced through exaggeration due to competition, but it may also vary with the age of the nestling. Younger nestlings may vary more in how frequently they call than older nestlings because they cannot discriminate stimuli as well. Thus, even if 'honest', begging from younger nestlings could be a less reliable hunger signal than that from older nestlings. We tested the prediction that parents should respond less to the increased frequency of begging from very young versus older nestlings by playing back begging calls at the nests of both younger (</=5 day) and older (>/=6 days) red-winged blackbirds, Agelaius phoeniceus. In neither case did parents respond with consistent increases in feeding, nor did young gain more weight during playbacks. This lack of response is discussed in relation to two other recent studies of blackbirds that did demonstrate increased feeding with playbacks of begging calls. Copyright 1998 The Association for the Study of Animal Behaviour.
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Affiliation(s)
- AB Clark
- Department of Biological Sciences, Binghamton University
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36
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Clark AB, Holt JM. Identifying and managing patients with hyperlipidemia. Am J Manag Care 1997; 3:1211-9; quiz 1223-5. [PMID: 10170303] [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: 02/11/2023]
Abstract
Cardiovascular disease related to hyperlipidemia is a significant cause of morbidity and mortality in the United States. The benefit of lowering lipid levels in patients with and without cardiovascular disease has been demonstrated in numerous clinical trials. The results of these trials prompted the National Heart, Blood, and Lung Institute to form the Nation Cholesterol Education Panel (NCEP). This panel developed guidelines for identifying and treating lipid disorders. Before starting antilipemic therapy, patients should be evaluated for secondary causes of hyperlipidemia, including disease states and medications. Risk factors for cardiovascular disease should be identified and used to determine the patient's goal low-density lipoprotein level. Regardless of the drug therapy used, the cornerstone treatment for hyperlipidemia is dietary changes. The NCEP recommendation for dietary modification follows a two-step plan to reduce intake of cholesterol and dietary fats. Other nonpharmacologic treatments for hyperlipidemia include exercise, weight reduction for obese patients, reduction of excessive alcohol use, and smoking cessation . Drug therapy should be considered in patients who do not respond to an adequate trial of dietary modifications and lifestyle changes. The principal lipid-lowering agents currently used are the bile acid sequestrants, nicotinic acid, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors, and fibric acid derivatives. Estrogen, fish oil, and alcohol also can decrease the risk of developing heart disease. In pharmacoeconomic studies, lipid-lowering drug therapy has been shown to decrease the number of procedures, hospitalizations, and other medical interventions required by patients with cardiovascular disease.
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Affiliation(s)
- A B Clark
- Department of Pharmacy Services, Veteran's Affairs Medical Center, Memphis, TN, USA
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Abstract
OBJECTIVE To describe a patient with cryptococcal meningitis treated with the combination of amphotericin B and fluconazole. CASE SUMMARY A 41-year-old woman with cryptococcal meningitis who was not infected with HIV was treated with a combination of amphotericin B and fluconazole because she did not respond to amphotericin B alone and could not tolerate amphotericin B with flucytosine. She improved clinically, but it is unclear whether the combination was beneficial. DISCUSSION Standard therapy for cryptococcal meningitis is amphotericin B with or without flucytosine. Fluconazole is an alternative therapy, but its efficacy has not been documented in the patient population not infected with HIV. Theoretically, the combination of amphotericin B and fluconazole is antagonistic, but in vitro and in vivo data suggest that antagonism may not occur. The combination of amphotericin B and fluconazole in cryptococcal meningitis has not been evaluated in clinical trials, and its use is not recommended. CONCLUSIONS A patient with cryptococcal meningitis was treated with the combination of amphotericin B and fluconazole because of a poor response to amphotericin B monotherapy and intolerance to flucytosine. It is unclear whether her clinical response was a result of the combination.
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Affiliation(s)
- A B Clark
- Department of Pharmacy, University of Tennessee, USA
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38
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Abstract
A two-hybrid system was used to screen yeast and human expression libraries for proteins that interact with mismatch repair proteins. PCNA was recovered from both libraries and shown in the case of yeast to interact with both MLH1 and MSH2. A yeast strain containing a mutation in the PCNA gene had a strongly elevated mutation rate in a dinucleotide repeat, and the rate was not further elevated in a strain also containing a mutation in MLH1. Mismatch repair activity was examined in human cell extracts using an assay that does not require DNA repair synthesis. Activity was inhibited by p21WAF1 or a p21 peptide, both of which bind to PCNA, and activity was restored to inhibited reactions by addition of PCNA. The data suggest a PCNA requirement in mismatch repair at a step preceding DNA resynthesis. The ability of PCNA to bind to MLH1 and MSH2 may reflect linkage between mismatch repair and replication and may be relevant to the roles of mismatch repair proteins in other DNA transactions.
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Affiliation(s)
- A Umar
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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Clark AB, Randell SH, Nettesheim P, Gray TE, Bagnell B, Ostrowski LE. Regulation of ciliated cell differentiation in cultures of rat tracheal epithelial cells. Am J Respir Cell Mol Biol 1995; 12:329-38. [PMID: 7873199 DOI: 10.1165/ajrcmb.12.3.7873199] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [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: 01/27/2023] Open
Abstract
The cellular pathway of ciliated cell differentiation and its regulation is poorly defined. To begin to understand the process of ciliated cell differentiation, we sought to identify factors regulating ciliated cell development in vitro. Rat tracheal epithelial (RTE) cells were cultured on collagen gel-coated membranes at an air-liquid interface in hormone- and growth factor-supplemented medium (complete medium [CM]). Under these conditions, RTE cells first proliferate and then differentiate into a pseudostratified mucociliary epithelium. Ciliated cell differentiation was measured using a monoclonal antibody, RTE3, which was shown to specifically react with the plasma membrane of ciliated cells. Cultures were immunostained in situ, and the percentage of the culture surface covered with ciliated cells was estimated using videomicroscopy and an image analysis program. If an air-liquid interface was not created and the cells were maintained in the submerged state, ciliated cell differentiation was suppressed 25-fold. Culture in the absence of mitogenic components present in CM, including epidermal growth factor (EGF), cholera toxin (CT), or bovine pituitary extract, resulted in 2- to 4-fold increases in the percentage of ciliated cells. When both EGF and CT were removed from the media, DNA synthesis and total cell number was reduced, while ciliated cell differentiation increased as much as 5-fold. These results demonstrate that submersion inhibits, while withdrawal of mitogenic compounds promotes, ciliated cell differentiation in vitro.
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Affiliation(s)
- A B Clark
- Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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Affiliation(s)
- L E Ostrowski
- Laboratory of Pulmonary Pathobiology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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41
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Abstract
Monozygotic twinning is rare within populations yet taxonomically widespread. We explore the evolution of monozygotic twinning by modeling an allele in a newly formed offspring that causes it to undergo mitosis and separation to form one or more clones (twins), potentially in conflict with the parents' best interest. The success of this twinning allele in our haploid models depends on the balance of the benefit of increased frequency in the clutch and the cost of reduced survival resulting from limited parental resources. The trait reaches high frequency in a broad range of plausible conditions but also fails to spread or is kept at low frequency in others when the survival cost is high (e.g., in small clutch sizes). Interestingly, there are two reasonable conditions that predict high frequency of the trait but low visibility: random parental abortion and selection for low penetrance. Thus our models suggest reasons why monozygotic twinning might be rare, or alternatively, be common yet appear rare. In addition, we discuss the implications for sex-linked twinning, dizygotic twinning, and twinning by gametes.
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Affiliation(s)
- S K Gleeson
- School of Biological Sciences, University of Kentucky, Lexington 40506
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Dykstra CC, Kitada K, Clark AB, Hamatake RK, Sugino A. Cloning and characterization of DST2, the gene for DNA strand transfer protein beta from Saccharomyces cerevisiae. Mol Cell Biol 1991; 11:2583-92. [PMID: 1850100 PMCID: PMC360028 DOI: 10.1128/mcb.11.5.2583-2592.1991] [Citation(s) in RCA: 40] [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] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The gene encoding the 180-kDa DNA strand transfer protein beta from the yeast Saccharomyces cerevisiae was identified and sequenced. This gene, DST2 (DNA strand transferase 2), was located on chromosome VII. dst2 gene disruption mutants exhibited temperature-sensitive sporulation and a 50% longer generation time during vegetative growth than did the wild type. Spontaneous mitotic recombination in the mutants was reduced severalfold for both intrachromosomal recombination and intragenic gene conversion. The mutants also had reduced levels of the intragenic recombination that is induced during meiosis. Meiotic recombinants were, however, somewhat unstable in the mutants, with a decrease in recombinants and survival upon prolonged incubation in sporulation media. spo13 or spo13 rad50 mutations did not relieve the sporulation defect of dst2 mutations. A dst1 dst2 double mutant has the same phenotype as a dst2 single mutant. All phenotypes associated with the dst2 mutations could be complemented by a plasmid containing DST2.
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Affiliation(s)
- C C Dykstra
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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Clark AB, Dykstra CC, Sugino A. Isolation, DNA sequence, and regulation of a Saccharomyces cerevisiae gene that encodes DNA strand transfer protein alpha. Mol Cell Biol 1991; 11:2576-82. [PMID: 1850099 PMCID: PMC360027 DOI: 10.1128/mcb.11.5.2576-2582.1991] [Citation(s) in RCA: 25] [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: 12/29/2022] Open
Abstract
DNA strand transfer protein alpha (STP alpha) from meiotic Saccharomyces cerevisiae cells promotes homologous pairing of DNA without any nucleotide cofactor in the presence of yeast single-stranded DNA binding protein. This gene (DNA strand transferase 1, DST1) encodes a 309-amino-acid protein with a predicted molecular mass of 34,800 Da. The STP alpha protein level is constant in both mitotic and meiotic cells, but during meiosis the polypeptide is activated by an unknown mechanism, resulting in a large increase in its specific activity. A dst1::URA3/dst1::URA3 mutant grows normally in mitotic media; however, meiotic cells exhibit a greatly reduced induction of both DNA strand transfer activity and intragenic recombination between his1 heteroalleles. Spore viability is normal. These results suggest that DST1 is required for much of the observed induction of homologous recombination in S. cerevisiae during meiosis but not for normal sporulation.
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Affiliation(s)
- A B Clark
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709
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Clark AB, Sims MR, Leppard PI. An analysis of the effect of tooth intrusion on the microvascular bed and fenestrae in the apical periodontal ligament of the rat molar. Am J Orthod Dentofacial Orthop 1991; 99:21-9. [PMID: 1986518 DOI: 10.1016/s0889-5406(05)81676-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An analysis of the rat apical periodontal ligament (PDL) microvascular bed and fenestrae was conducted to evaluate the effect of a continuous 1.0 N intrusive tooth load for 30 minutes. The microvascular bed consisted of postcapillary-sized venules, venous and arterial capillaries, and terminal arterioles. Intrusion produced significant increases (p less than 0.01) in vascular volume for postcapillary-sized venules and venous capillaries in three of the four animals. Arterial capillaries, overall, showed a statistically significant increase (p less than 0.01). The endothelial surface area (micron2 x 10(6)) per cubic millimeter of PDL responded variably in postcapillary-sized venules and venous capillaries but showed a strong trend to increase in arterial capillaries. After tooth intrusion a significant reduction (p less than 0.01) occurred in the number of fenestrae per square micrometer of endothelium in postcapillary-sized venules and venous capillaries. Fenestrae in the control PDL had a mean diameter of 51.5 nm +/- 0.6 (SE), whereas those on the intrusion side were smaller (p less than 0.05), measuring 49.9 nm +/- 0.4 (SE).
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Affiliation(s)
- A B Clark
- Department of Dentistry, University of Adelaide, Australia
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Abstract
DNA polymerases I and III are essential for viability of S. cerevisiae. We have cloned and analyzed POL2, the gene encoding the catalytic subunit of the third nuclear DNA polymerase, DNA polymerase II. POL2 expressed a transcript of approximately 7.5 kb and contained a reading frame that encoded a protein of calculated Mr 255,649. The N-terminal half of the predicted protein displayed relatively weak similarity of sequence to eukaryotic DNA polymerases. Disruption of the coding sequence at midpoint led to viable, slowly growing cells, which yielded a truncated polypeptide with DNA polymerase II activity, free from subunits B or C. Deletion of the reading frame resulted in inviability and the dumbbell terminal morphology that typically follows arrest of DNA replication. We conclude that three DNA polymerases are essential in yeast and argue that all three are replicases, a possibility that challenges existing models of eukaryotic DNA replication.
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Affiliation(s)
- A Morrison
- Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences Research Triangle Park, North Carolina 27709
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Hamatake RK, Hasegawa H, Clark AB, Bebenek K, Kunkel TA, Sugino A. Purification and characterization of DNA polymerase II from the yeast Saccharomyces cerevisiae. Identification of the catalytic core and a possible holoenzyme form of the enzyme. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39704-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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47
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Landis BA, Rotolo FS, Meyers WC, Clark AB, Quarfordt SH. Influence of apolipoprotein E on soluble and heparin-immobilized hepatic lipase. Am J Physiol 1987; 252:G805-10. [PMID: 3591946 DOI: 10.1152/ajpgi.1987.252.6.g805] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The effect of human apolipoprotein E (apoE), either alone or in combination with apoC, on the lipolysis of a radiolabeled triglyceride emulsion was studied with hepatic lipase in solution and immobilized on heparin-Sepharose. The soluble hepatic lipase was inhibited, whereas the heparin-immobilized lipase was stimulated by apoE. This stimulation was attenuated by combining apoE with either apoC-II or C-III. The heparin-immobilized lipase demonstrated much less lipolysis of the zwitterionic phosphatidylcholine-stabilized triglyceride emulsion than did the soluble enzyme. This difference was less when the emulsion was stabilized by a nonionic detergent. apoE inhibited lipase activity when assayed under conditions (0.4 M NaCl) of bound enzyme and unbound substrate. Increasing the emulsion apoE content beyond optimum inhibited lipolysis by the immobilized enzyme. Kinetic analysis of phosphatidylcholine-stabilized triglyceride emulsions revealed a significant decrease in immobilized enzyme Km and an increase in Vmax when the emulsion was supplemented with apoE. Distributing the immobilized lipase in clustered aggregates produced more lipolysis than when the same enzyme content was uniformly bound.
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Clark AB, Quarfordt SH. Apolipoprotein effects on the lipolysis of perfused triglyceride by heparin-immobilized milk lipase. J Biol Chem 1985; 260:4778-83. [PMID: 3988735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Bovine milk lipase was noncovalently bound to a heparin-Sepharose support and a [3H]glycerol/[14C]triolein emulsion was circulated through it. This system, more closely simulating in vivo conditions than the standard lipoprotein lipase assay, was employed to determine the effect of human apo-E and apo-C-II on the lipolysis of the circulating substrate. Both apo-C-II and apo-E produced enhanced lipolysis in comparison to unsupplemented emulsions, at appropriate enzyme densities on the heparin-Sepharose. With high enzyme densities the stimulation produced by apo-E was lost but that of apo-C-II persisted. When apo-E and apo-C-II were added together they produced significantly more lipolysis than when either was added separately. The enhancement of lipolysis produced by apo-E was correlated with the increased binding of triglyceride to the heparin-Sepharose enzyme complex. The effect of additions of both apoproteins to rat intestinal chylomicrons resulted in data quite similar to the triglyceride emulsions. Heparin-Sepharose columns with high and low zones of enzyme density produced greater lipolysis than when the enzyme was distributed more uniformly throughout the column. Perfusions of substrate supplemented with sufficient apo-E to produce maximal binding and lipolysis resulted in a progressive elution of the triglyceride substrate from the column during the perfusion. Free fatty acid:albumin molar ratios greater than 2 resulted in desorption of substrate from the column. This suggests the possibility of regulation of the lipolytic process by the products of lipolysis.
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Abstract
Competition between female kin for local limiting resources may explain a male-biased secondary sex ratio in the prosimian Galago crassicaudatus. Data demonstrating the skewed sex ratio, a brief summary of field observations on the species, and a simple mathematical statement of the hypothesis are presented. Local resource competition may influence sex ratio in other mammals.
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Clark AB, Miller MD. High pressure liquid chromatographic separation of dyes encountered in illicit heroin samples. J Forensic Sci 1978; 23:21-8. [PMID: 744963] [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: 12/24/2022]
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