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Morris G, Walker AJ, Walder K, Berk M, Marx W, Carvalho AF, Maes M, Puri BK. Increasing Nrf2 Activity as a Treatment Approach in Neuropsychiatry. Mol Neurobiol 2021; 58:2158-2182. [PMID: 33411248 DOI: 10.1007/s12035-020-02212-w] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 11/16/2020] [Indexed: 02/07/2023]
Abstract
Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor encoded by NFE2L2. Under oxidative stress, Nrf2 does not undergo its normal cytoplasmic degradation but instead travels to the nucleus, where it binds to a DNA promoter and initiates transcription of anti-oxidative genes. Nrf2 upregulation is associated with increased cellular levels of glutathione disulfide, glutathione peroxidase, glutathione transferases, thioredoxin and thioredoxin reductase. Given its key role in governing the cellular antioxidant response, upregulation of Nrf2 has been suggested as a common therapeutic target in neuropsychiatric illnesses such as major depressive disorder, bipolar disorder and schizophrenia, which are associated with chronic oxidative and nitrosative stress, characterised by elevated levels of reactive oxygen species, nitric oxide and peroxynitrite. These processes lead to extensive lipid peroxidation, protein oxidation and carbonylation, and oxidative damage to nuclear and mitochondrial DNA. Intake of N-acetylcysteine, coenzyme Q10 and melatonin is accompanied by increased Nrf2 activity. N-acetylcysteine intake is associated with improved cerebral mitochondrial function, decreased central oxidative and nitrosative stress, reduced neuroinflammation, alleviation of endoplasmic reticular stress and suppression of the unfolded protein response. Coenzyme Q10, which acts as a superoxide scavenger in neuroglial mitochondria, instigates mitohormesis, ameliorates lipid peroxidation in the inner mitochondrial membrane, activates uncoupling proteins, promotes mitochondrial biogenesis and has positive effects on the plasma membrane redox system. Melatonin, which scavenges mitochondrial free radicals, inhibits mitochondrial nitric oxide synthase, restores mitochondrial calcium homeostasis, deacetylates and activates mitochondrial SIRT3, ameliorates increased permeability of the blood-brain barrier and intestine and counters neuroinflammation and glutamate excitotoxicity.
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Affiliation(s)
- G Morris
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Barwon Health, School of Medicine, Deakin University, Geelong, VIC, Australia
| | - A J Walker
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Barwon Health, School of Medicine, Deakin University, Geelong, VIC, Australia
| | - K Walder
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Barwon Health, School of Medicine, Deakin University, Geelong, VIC, Australia
| | - M Berk
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Barwon Health, School of Medicine, Deakin University, Geelong, VIC, Australia.,CMMR Strategic Research Centre, School of Medicine, Deakin University, Geelong, VIC, Australia.,Orygen, The National Centre of Excellence in Youth Mental Health, The Department of Psychiatry and the Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - W Marx
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Barwon Health, School of Medicine, Deakin University, Geelong, VIC, Australia
| | - A F Carvalho
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - M Maes
- Institute for Mental and Physical Health and Clinical Translation (IMPACT), Barwon Health, School of Medicine, Deakin University, Geelong, VIC, Australia.,Department of Psychiatry, Chulalongkorn University, Bangkok, Thailand
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Abstract
AbstractThroughout recent history there has been a pattern whereby military medical care improves in wartime and these advances are lost by the time the next conflict occurs. This dip in medical performance potentially represents lives that may be lost and recovery that may be impaired for our young servicemen and women at the start of every new conflict. When reviewing the wars of the last two centuries, three themes emerge. Firstly, post-war military cuts fall disproportionately on medical services, leaving a mismatch between the size of forces that can be deployed and the ability to care for them when injured. Secondly, insufficient medical representation in military operational planning results in the neglect of medical logistics; and finally, technical and procedural lessons are not adequately captured and incorporated into training and doctrine.
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Nettey OS, Walker AJ, Keeter MK, Singal A, Nugooru A, Martin IK, Ruden M, Gogana P, Dixon MA, Osuma T, Hollowell CMP, Sharifi R, Sekosan M, Yang X, Catalona WJ, Kajdacsy-Balla A, Macias V, Kittles RA, Murphy AB. Self-reported Black race predicts significant prostate cancer independent of clinical setting and clinical and socioeconomic risk factors. Urol Oncol 2018; 36:501.e1-501.e8. [PMID: 30236853 DOI: 10.1016/j.urolonc.2018.06.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/11/2018] [Accepted: 06/26/2018] [Indexed: 12/24/2022]
Abstract
INTRODUCTION AND OBJECTIVE Studies have linked Black race to prostate cancer (CaP) risk but most fail to account for established risk factors such as 5-ARI use, prostate volume, socioeconomic status, and hospital setting. We assess whether Black race remains associated with CaP and Gleason ≥3 + 4 CaP, after adjusting for clinical setting and socioeconomic and clinical factors at prostate biopsy, with a focus on men aged 40-54 years, who may be excluded from current screening guidelines. METHODS We recruited 564 men age 40-79 undergoing initial prostate biopsy for abnormal PSA or digital rectal examination (DRE) from three publicly funded and two private hospitals from 2009-2014. Univariate and multivariate analyses examined the associations between hospital type, race, West African Ancestry (WAA), clinical, and sociodemographic risk factors with CaP diagnosis and Gleason ≥3 + 4 CaP. Given changes in CaP screening recommendations, we also assess the multivariate analyses for men aged 40-54. RESULTS Black and White men had similar age, BMI, and prostate volume. Black men had higher PSA (8.10 ng/mL vs. 5.63 ng/mL) and PSA density (0.22 ng/mL/cm3 vs. 0.15 ng/mL/cm3, all p < 0.001). Blacks had higher frequency of CaP (63.1% vs. 41.5%, p<0.001) and Gleason ≥3+4 CaP relative to Whites in both public (27.7% vs 11.6%, p<0.001) and private (48.4% vs 21.6%, p = 0.002) settings. In models adjusted for age, first degree family history, prostate volume, 5-ARI use, hospital type, income, marital and educational status, Black race was independently associated with overall CaP diagnosis (OR = 2.13, p = 0.002). There was a significant multiplicative interaction with Black race and abnormal DRE for Gleason ≥3 + 4 CaP (OR = 2.93, p = 0.01). WAA was not predictive of overall or significant CaP among Black men. Black race (OR = 5.66, p = 0.02) and family history (OR = 4.98, p = 0.01) were independently positively associated with overall CaP diagnosis for men aged 40 to 54. CONCLUSIONS Black race is independently associated with CaP and Gleason ≥3+4 CaP after accounting for clinical and socioeconomic risk factors including clinical setting and WAA, and has a higher odds ratio of CaP diagnosis in younger men. Further investigation into optimizing screening in Black men aged 40 to 54 is warranted.
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Affiliation(s)
- Oluwarotimi S Nettey
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Austin J Walker
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Mary Kate Keeter
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Ashima Singal
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Aishwarya Nugooru
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Iman K Martin
- Division of Cancer Prevention, National Cancer Institute, Bethesda, MD
| | - Maria Ruden
- Department of Medicine, University of Illinois at Chicago, Chicago, IL
| | - Pooja Gogana
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Michael A Dixon
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | | | | | - Roohollah Sharifi
- Section of Urology, Jesse Brown VA Medical Center, Chicago, IL; Department of Urology, University of Illinois at Chicago School of Medicine, Chicago, IL
| | - Marin Sekosan
- Department of Pathology, Cook County Health and Hospitals System, Chicago, IL
| | - Ximing Yang
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - William J Catalona
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Andre Kajdacsy-Balla
- Department of Pathology, University of Illinois at Chicago School of Medicine, Chicago, IL
| | - Virgilia Macias
- Department of Pathology, University of Illinois at Chicago School of Medicine, Chicago, IL
| | - Rick A Kittles
- Division of Health Equities, Department of Population Sciences, City of Hope Cancer Center, Duarte, CA
| | - Adam B Murphy
- Department of Urology, Northwestern University Feinberg School of Medicine, Chicago, IL; Section of Urology, Jesse Brown VA Medical Center, Chicago, IL.
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Abstract
In the first part, the following mechanisms involved in different forms of cell death are considered, with a view to identifying potential therapeutic targets: tumour necrosis factor receptors (TNFRs) and their engagement by tumour necrosis factor-alpha (TNF-α); poly [ADP-ribose] polymerase (PARP)-1 cleavage; the apoptosis signalling kinase (ASK)-c-Jun N-terminal kinase (JNK) axis; lysosomal permeability; activation of programmed necrotic cell death; oxidative stress, caspase-3 inhibition and parthanatos; activation of inflammasomes by reactive oxygen species and the development of pyroptosis; oxidative stress, calcium dyshomeostasis and iron in the development of lysosomal-mediated necrosis and lysosomal membrane permeability; and oxidative stress, lipid peroxidation, iron dyshomeostasis and ferroptosis. In the second part, there is a consideration of the role of lethal and sub-lethal activation of these pathways in the pathogenesis and pathophysiology of neurodegenerative and neuroprogressive disorders, with particular reference to the TNF-α-TNFR signalling axis; dysregulation of ASK-1-JNK signalling; prolonged or chronic PARP-1 activation; the role of pyroptosis and chronic inflammasome activation; and the roles of lysosomal permeabilisation, necroptosis and ferroptosis. Finally, it is suggested that, in addition to targeting oxidative stress and inflammatory processes generally, neuropsychiatric disorders may respond to therapeutic targeting of TNF-α, PARP-1, the Nod-like receptor NLRP3 inflammasome and the necrosomal molecular switch receptor-interacting protein kinase-3, since their widespread activation can drive and/or exacerbate peripheral inflammation and neuroinflammation even in the absence of cell death. To this end, the use is proposed of a combination of the tetracycline derivative minocycline and N-acetylcysteine as adjunctive treatment for a range of neuropsychiatric disorders.
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Affiliation(s)
- G Morris
- , Bryn Road Seaside 87, Llanelli, Wales, , SA15 2LW, UK
- School of Medicine, Deakin University, Geelong, 3220, Australia
| | - A J Walker
- School of Medicine, Deakin University, Geelong, 3220, Australia
| | - M Berk
- The Centre for Molecular and Medical Research, School of Medicine, Deakin University, P.O. Box 291, Geelong, 3220, Australia
- Department of Clinical Medicine and Translational Psychiatry Research Group, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, 60430-040, Brazil
- IMPACT Strategic Research Centre, School of Medicine, Deakin University, P.O. Box 291, Geelong, 3220, Australia
- Orygen Youth Health Research Centre and the Centre of Youth Mental Health, The Florey Institute for Neuroscience and Mental Health and the Department of Psychiatry, University of Melbourne, Parkville, 3052, Australia
| | - M Maes
- School of Medicine, Deakin University, Geelong, 3220, Australia
- Department of Psychiatry, Chulalongkorn University, Bangkok, Thailand
| | - B K Puri
- Department of Medicine, Hammersmith Hospital, Imperial College London, London, W12 0HS, UK.
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Affiliation(s)
- S P Amoils
- Department of Ophthalmology, Baragwanath Hospital, and the University of the Witwatersrand, Johannesburg, South Africa
| | - A J Walker
- Spembly Technical Products, Sittingbourne, Kent
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Kim Y, McGee S, Czeczor JK, Walker AJ, Kale RP, Kouzani AZ, Walder K, Berk M, Tye SJ. Nucleus accumbens deep-brain stimulation efficacy in ACTH-pretreated rats: alterations in mitochondrial function relate to antidepressant-like effects. Transl Psychiatry 2016; 6:e842. [PMID: 27327257 PMCID: PMC4931612 DOI: 10.1038/tp.2016.84] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 02/02/2016] [Accepted: 02/25/2016] [Indexed: 02/08/2023] Open
Abstract
Mitochondrial dysfunction has a critical role in the pathophysiology of mood disorders and treatment response. To investigate this, we established an animal model exhibiting a state of antidepressant treatment resistance in male Wistar rats using 21 days of adrenocorticotropic hormone (ACTH) administration (100 μg per day). First, the effect of ACTH treatment on the efficacy of imipramine (10 mg kg(-1)) was investigated alongside its effect on the prefrontal cortex (PFC) mitochondrial function. Second, we examined the mood-regulatory actions of chronic (7 day) high-frequency nucleus accumbens (NAc) deep-brain stimulation (DBS; 130 Hz, 100 μA, 90 μS) and concomitant PFC mitochondrial function. Antidepressant-like responses were assessed in the open field test (OFT) and forced swim test (FST) for both conditions. ACTH pretreatment prevented imipramine-mediated improvement in mobility during the FST (P<0.05). NAc DBS effectively improved FST mobility in ACTH-treated animals (P<0.05). No improvement in mobility was observed for sham control animals (P>0.05). Analyses of PFC mitochondrial function revealed that ACTH-treated animals had decreased capacity for adenosine triphosphate production compared with controls. In contrast, ACTH animals following NAc DBS demonstrated greater mitochondrial function relative to controls. Interestingly, a proportion (30%) of the ACTH-treated animals exhibited heightened locomotor activity in the OFT and exaggerated escape behaviors during the FST, together with general hyperactivity in their home-cage settings. More importantly, the induction of this mania-like phenotype was accompanied by overcompensative increased mitochondrial respiration. Manifestation of a DBS-induced mania-like phenotype in imipramine-resistant animals highlights the potential use of this model in elucidating mechanisms of mood dysregulation.
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Affiliation(s)
- Y Kim
- School of Psychology, Faculty of Health, Deakin University, Melbourne, VIC, Australia,Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA
| | - S McGee
- Centre for Molecular and Medical Research, School of Medicine, Faculty of Health, Deakin University, Melbourne, VIC, Australia,Metabolism and Inflammation Program, Baker IDI Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - J K Czeczor
- Centre for Molecular and Medical Research, School of Medicine, Faculty of Health, Deakin University, Melbourne, VIC, Australia
| | - A J Walker
- School of Psychology, Faculty of Health, Deakin University, Melbourne, VIC, Australia,Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA
| | - R P Kale
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA,School of Engineering, Faculty of Science Engineering and Built Environment, Deakin University, Geelong, VIC, Australia
| | - A Z Kouzani
- School of Engineering, Faculty of Science Engineering and Built Environment, Deakin University, Geelong, VIC, Australia
| | - K Walder
- Centre for Molecular and Medical Research, School of Medicine, Faculty of Health, Deakin University, Melbourne, VIC, Australia
| | - M Berk
- Deakin University IMPACT Strategic Research Centre, School of Medicine, Faculty of Health, Geelong, VIC, Australia
| | - S J Tye
- School of Psychology, Faculty of Health, Deakin University, Melbourne, VIC, Australia,Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA,Department of Psychiatry, University of Minnesota, Rochester, MN, USA,Department of Psychiatry and Psychology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA. E-mail:
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Humes DJ, Walker AJ, Hunt BJ, Sultan AA, Ludvigsson JF, West J. Risk of symptomatic venous thromboembolism following emergency appendicectomy in adults. Br J Surg 2016; 103:443-50. [DOI: 10.1002/bjs.10091] [Citation(s) in RCA: 13] [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] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/30/2015] [Accepted: 11/23/2015] [Indexed: 12/25/2022]
Abstract
Abstract
Background
Appendicectomy is the commonest intra-abdominal emergency surgical procedure, and little is known regarding the magnitude and timing of the risk of venous thromboembolism (VTE) after surgery. This study aimed to determine absolute and relative rates of symptomatic VTE following emergency appendicectomy.
Methods
A cohort study was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data of patients who had undergone emergency appendicectomy from 2001 to 2011. Crude rates and adjusted incidence rate ratios (IRRs) for VTE were calculated using Poisson regression, compared with baseline risk in the year before appendicectomy.
Results
A total of 13 441 patients were identified, of whom 56 (0·4 per cent) had a VTE in the first year after surgery. The absolute rate of VTE was highest during the in-hospital period, with a rate of 91·29 per 1000 person-years, which was greatest in those with a length of stay of 7 days or more (267·12 per 1000 person-years). This risk remained high after discharge, with a 19·1- and 6·6-fold increased risk of VTE in the first and second months respectively after discharge, compared with the year before appendicectomy (adjusted IRR: month 1, 19·09 (95 per cent c.i. 9·56 to 38·12); month 2, 6·56 (2·62 to 16·44)).
Conclusion
The risk of symptomatic VTE following appendicectomy is relatively high during the in-hospital admission and remains increased after discharge. Trials of extended thromboprophylaxis are warranted in patients at particularly high risk.
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Affiliation(s)
- D J Humes
- Division of Epidemiology and Public Health, School of Medicine, Queens Medical Centre Campus, University of Nottingham, Nottingham, UK
- Nottingham Digestive Diseases Biomedical Research Unit, Queens Medical Centre Campus, University of Nottingham, Nottingham, UK
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
| | - A J Walker
- Division of Epidemiology and Public Health, School of Medicine, Queens Medical Centre Campus, University of Nottingham, Nottingham, UK
| | - B J Hunt
- Thrombosis and Haemophilia Centre, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - A A Sultan
- Division of Epidemiology and Public Health, School of Medicine, Queens Medical Centre Campus, University of Nottingham, Nottingham, UK
| | - J F Ludvigsson
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
- Department of Paediatrics, Örebro University Hospital, Örebro, Sweden
| | - J West
- Division of Epidemiology and Public Health, School of Medicine, Queens Medical Centre Campus, University of Nottingham, Nottingham, UK
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Humes DJ, Walker AJ, Blackwell J, Hunt BJ, West J. Variation in the risk of venous thromboembolism following colectomy. Br J Surg 2015; 102:1629-38. [DOI: 10.1002/bjs.9923] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/01/2015] [Accepted: 07/22/2015] [Indexed: 02/05/2023]
Abstract
Abstract
Background
Guidelines recommend extended thromboprophylaxis following colectomy for malignant disease, but not for non-malignant disease. The aim of this study was to determine absolute and relative rates of venous thromboembolism (VTE) following colectomy by indication, admission type and time after surgery.
Methods
A cohort study of patients undergoing colectomy in England was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data (2001–2011). Crude rates and adjusted hazard ratios (HRs) were calculated for the risk of first VTE following colectomy using Cox regression analysis.
Results
Some 12 388 patients were identified; 312 (2·5 per cent) developed VTE after surgery, giving a rate of 29·59 (95 per cent c.i. 26·48 to 33·06) per 1000 person-years in the first year after surgery. Overall rates were 2·2-fold higher (adjusted HR 2·23, 95 per cent c.i. 1·76 to 2·50) for emergency compared with elective admissions (39·44 versus 25·78 per 1000 person-years respectively). Rates of VTE were 2·8-fold higher in patients with malignant disease versus those with non-malignant disease (adjusted HR 2·84, 2·04 to 3·94). The rate of VTE was highest in the first month after emergency surgery, and declined from 121·68 per 1000 person-years in the first month to 25·65 per 1000 person-years during the rest of the follow-up interval. Crude rates of VTE were similar for malignant and non-malignant disease (114·76 versus 120·98 per 1000 person-years respectively) during the first month after emergency surgery.
Conclusion
Patients undergoing emergency colectomy for non-malignant disease have a similar risk of VTE as patients with malignant disease in the first month after surgery.
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Affiliation(s)
- D J Humes
- Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK
- National Institute for Health Research Nottingham Digestive Disease Biomedical Research Unit, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, UK
| | - A J Walker
- Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK
| | - J Blackwell
- Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK
| | - B J Hunt
- Thrombosis and Haemophilia Centre, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, London, UK
| | - J West
- Division of Epidemiology and Public Health, School of Medicine, University of Nottingham, Nottingham, UK
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Walker AJ, West J, Card TR, Humes DJ, Grainge MJ. Variation in the risk of venous thromboembolism in people with colorectal cancer: a population-based cohort study from England. J Thromb Haemost 2014; 12:641-9. [PMID: 24977288 PMCID: PMC4230392 DOI: 10.1111/jth.12533] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND Patients with colorectal cancer are at high risk of developing venous thromboembolism(VTE), and recent international guidelines have advised extended prophylaxis for some of these patients following surgery or during chemotherapy. However, our understanding of which patients are at increased risk, and to what extent, is limited. OBJECTIVES To determine absolute and relative rates of VTE among patients with colorectal cancer according to Dukes stage, surgical intervention,and chemotherapy. METHODS We analyzed data from four linked databases from 1997 to 2006: the Clinical Practice Research Datalink, linked to Hospital Episode Statistics, Cancer Registry data, and Office for National Statistics cause of death data, all from England. Rates were compared by the use of Cox regression. RESULTS There were 10 309 patients with colorectal cancer, and 555 developed VTE (5.4%). The incidence varied by Dukes stage, being three-fold higher among Dukes D patients than among Dukes A patients (hazard ratio [HR] 3.08, 95% confidence interval [CI] 1.95–4.84), and 40% higher for those receiving chemotherapy than for those not receiving chemotherapy(HR 1.39, 95% CI 1.14–1.69). The risk following surgery varied by stage of disease and chemotherapy, with Dukes A patients having a low incidence of VTE (0.74%; 95% CI 0.28–1.95) at 6 months,with all events occurring within 28 days of surgery, as compared with Dukes B and Dukes C patients, whose risk at 6 months was ~ 2%. CONCLUSION Twenty-eight days of prophylaxis following surgery for colorectal cancer is appropriate for Dukes A patients. However, Dukes B and Dukes C patients receiving postoperative chemotherapy have a longer duration of risk.
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Abstract
Background: Aspirin has been widely reported to reduce the incidence of colorectal cancer. Recently, a survival benefit after diagnosis has also been suggested. Data regarding such a benefit are to date contradictory. This study examines the effect of non-steroidal anti-inflammatory drug (NSAID) use on mortality in colorectal cancer in a larger patient cohort than previously to further clarify this effect, especially in terms of exposure timing and dosing. Methods: A study using the General Practice Research Database assessed whether aspirin or NSAID exposure in the year immediately following diagnosis affected all-cause mortality in a cohort of 13 994 colorectal cancer patients. Cox proportional hazards modelling adjusted for age, gender, smoking, body mass index and comorbidity. Results: Overall mortality was slightly lower in patients treated with aspirin, (hazard ratio (HR)=0.91; 95% confidence interval (CI)=0.82–1.00). This effect was observed only in patients treated with prophylaxis-dose aspirin (HR=0.89, CI=0.80–0.98) and only in patients taking aspirin before diagnosis (HR=0.86, CI=0.76–0.98). Differential effects were observed depending on the time after diagnosis. Up to 5 years, a reduction in mortality was observed for aspirin users (HR=0.83, CI=0.75–0.92), whereas after 10 years there was an increase in mortality (HR=1.94, CI=1.26–2.99). For NSAID use, no significant effect was observed on overall mortality (HR=1.07, CI=0.98–1.15). High-dose NSAID use was associated with a slight increase in mortality (HR=1.41, CI=1.26–1.56). Interpretation: These findings provide further indication that aspirin may be beneficial in reducing mortality in colorectal cancer during the first 5 years. The same cannot be said for other NSAIDs, where a small increase in mortality was observed.
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Affiliation(s)
- A J Walker
- Division of Epidemiology and Public Health, School of Community Health Sciences, University of Nottingham, Nottingham City Hospital, Clinical Sciences Building, 07713 152268, Nottingham NG5 1PB, UK.
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Fraser JAV, Peacher DF, Freiberger JJ, Natoli MJ, Schinazi EA, Beck IV, Walker JR, Doar PO, Boso AE, Walker AJ, Kernagis DN, Moon RE. Risk factors for immersion pulmonary edema: hyperoxia does not attenuate pulmonary hypertension associated with cold water-immersed prone exercise at 4.7 ATA. J Appl Physiol (1985) 2010; 110:610-8. [PMID: 21148341 DOI: 10.1152/japplphysiol.01088.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Hyperoxia has been shown to attenuate the increase in pulmonary artery (PA) pressure associated with immersed exercise in thermoneutral water, which could serve as a possible preventive strategy for the development of immersion pulmonary edema (IPE). We tested the hypothesis that the same is true during exercise in cold water. Six healthy volunteers instrumented with arterial and PA catheters were studied during two 16-min exercise trials during prone immersion in cold water (19.9-20.9°C) in normoxia [0.21 atmospheres absolute (ATA)] and hyperoxia (1.75 ATA) at 4.7 ATA. Heart rate (HR), Fick cardiac output (CO), mean arterial pressure (MAP), pulmonary artery pressure (PAP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), arterial and venous blood gases, and ventilatory parameters were measured both early (E, 5-6 min) and late (L, 15-16 min) in exercise. During exercise at an average oxygen consumption rate (Vo(2)) of 2.38 l/min, [corrected] CO, CVP, and pulmonary vascular resistance were not affected by inspired (Vo(2)) [corrected] or exercise duration. Minute ventilation (Ve), alveolar ventilation (Va), and ventilation frequency (f) were significantly lower in hyperoxia compared with normoxia (mean ± SD: Ve 58.8 ± 8.0 vs. 65.1 ± 9.2, P = 0.003; Va 40.2 ± 5.4 vs. 44.2 ± 9.0, P = 0.01; f 25.4 ± 5.4 vs. 27.2 ± 4.2, P = 0.04). Mixed venous pH was lower in hyperoxia compared with normoxia (7.17 ± 0.07 vs. 7.20 ± 0.07), and this result was significant early in exercise (P = 0.002). There was no difference in mean PAP (MPAP: 28.28 ± 8.1 and 29.09 ± 14.3 mmHg) or PAWP (18.0 ± 7.6 and 18.7 ± 8.7 mmHg) between normoxia and hyperoxia, respectively. PAWP decreased from early to late exercise in hyperoxia (P = 0.002). These results suggest that the increase in pulmonary vascular pressures associated with cold water immersion is not attenuated with hyperoxia.
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Affiliation(s)
- J A V Fraser
- Dept. of Anesthesiology, Box 3094, Duke Univ. Medical Center, Durham, NC 27710, USA
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Abstract
A dynamic theory for compressible smectic C (SmC) liquid crystals is postulated following previous work by Leslie et al (1991 Mol. Cryst. Liq. Cryst. 198 443-54), Nakagawa (1996 J. Phys. Soc. Japan 65 100-6; 2004 J. Non-Newtonian Fluid Mech. 119 123-9) and de Gennes and Prost (1993 The Physics of Liquid Crystals 2nd edn (Oxford: Oxford University Press)). This theory is then implemented with a constructed bulk elastic energy and asymmetric stress tensor to describe a system of planar layered SmC liquid crystals undergoing various modes of undulation. We show that previous work on smectic A (SmA) liquid crystals by de Gennes and Prost (1993 The Physics of Liquid Crystals 2nd edn (Oxford: Oxford University Press)) can be expanded for SmC and consolidated. Novel and confirming estimates for SmC material parameter values are produced by considering the dependence of the system on these parameters.
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Affiliation(s)
- A J Walker
- Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK.
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14
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Abstract
This paper considers the dynamics of cylindrically arranged parallel layers of smectic A liquid crystal subjected to Couette flow. Governing equations are constructed using a recently developed dynamic theory for smectic A (Stewart 2007 Contin. Mech. Thermodyn. 18 343-60). These equations are solved to provide analytical solutions for the smectic layer undulations and velocity profiles. Results show the dependence of the response time of the smectic layers upon the permeation constant and the layer compression modulus. The relaxation times for the flow profiles are shown to depend upon two viscosities; estimates for these times are shown to be shorter than that for a typical approximation to the relaxation time of the smectic layer undulations.
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Affiliation(s)
- A J Walker
- Department of Mathematics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, UK
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15
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Wester TE, Cherry AD, Pollock NW, Freiberger JJ, Natoli MJ, Schinazi EA, Doar PO, Boso AE, Alford EL, Walker AJ, Uguccioni DM, Kernagis D, Moon RE. Effects of head and body cooling on hemodynamics during immersed prone exercise at 1 ATA. J Appl Physiol (1985) 2008; 106:691-700. [PMID: 19023017 DOI: 10.1152/japplphysiol.91237.2008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Immersion pulmonary edema (IPE) is a condition with sudden onset in divers and swimmers suspected to be due to pulmonary arterial or venous hypertension induced by exercise in cold water, although it does occur even with adequate thermal protection. We tested the hypothesis that cold head immersion could facilitate IPE via a reflex rise in pulmonary vascular pressure due solely to cooling of the head. Ten volunteers were instrumented with ECG and radial and pulmonary artery catheters and studied at 1 atm absolute (ATA) during dry and immersed rest and exercise in thermoneutral (29-31 degrees C) and cold (18-20 degrees C) water. A head tent varied the temperature of the water surrounding the head independently of the trunk and limbs. Heart rate, Fick cardiac output (CO), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), and central venous pressure (CVP) were measured. MPAP, PAWP, and CO were significantly higher in cold pool water (P < or = 0.004). Resting MPAP and PAWP values (means +/- SD) were 20 +/- 2.9/13 +/- 3.9 (cold body/cold head), 21 +/- 3.1/14 +/- 5.2 (cold/warm), 14 +/- 1.5/10 +/- 2.2 (warm/warm), and 15 +/- 1.6/10 +/- 2.6 mmHg (warm/cold). Exercise values were higher; cold body immersion augmented the rise in MPAP during exercise. MAP increased during immersion, especially in cold water (P < 0.0001). Except for a transient additive effect on MAP and MPAP during rapid head cooling, cold water on the head had no effect on vascular pressures. The results support a hemodynamic cause for IPE mediated in part by cooling of the trunk and extremities. This does not support the use of increased head insulation to prevent IPE.
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Affiliation(s)
- T E Wester
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
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Cherry AD, Forkner IF, Frederick HJ, Natoli MJ, Schinazi EA, Longphre JP, Conard JL, White WD, Freiberger JJ, Stolp BW, Pollock NW, Doar PO, Boso AE, Alford EL, Walker AJ, Ma AC, Rhodes MA, Moon RE. Predictors of increased PaCO2 during immersed prone exercise at 4.7 ATA. J Appl Physiol (1985) 2008; 106:316-25. [PMID: 18787095 DOI: 10.1152/japplphysiol.00885.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During diving, arterial Pco(2) (Pa(CO(2))) levels can increase and contribute to psychomotor impairment and unconsciousness. This study was designed to investigate the effects of the hypercapnic ventilatory response (HCVR), exercise, inspired Po(2), and externally applied transrespiratory pressure (P(tr)) on Pa(CO(2)) during immersed prone exercise in subjects breathing oxygen-nitrogen mixes at 4.7 ATA. Twenty-five subjects were studied at rest and during 6 min of exercise while dry and submersed at 1 ATA and during exercise submersed at 4.7 ATA. At 4.7 ATA, subsets of the 25 subjects (9-10 for each condition) exercised as P(tr) was varied between +10, 0, and -10 cmH(2)O; breathing gas Po(2) was 0.7, 1.0, and 1.3 ATA; and inspiratory and expiratory breathing resistances were varied using 14.9-, 11.6-, and 10.2-mm-diameter-aperture disks. During exercise, Pa(CO(2)) (Torr) increased from 31.5 +/- 4.1 (mean +/- SD for all subjects) dry to 34.2 +/- 4.8 (P = 0.02) submersed, to 46.1 +/- 5.9 (P < 0.001) at 4.7 ATA during air breathing and to 49.9 +/- 5.4 (P < 0.001 vs. 1 ATA) during breathing with high external resistance. There was no significant effect of inspired Po(2) or P(tr) on Pa(CO(2)) or minute ventilation (Ve). Ve (l/min) decreased from 89.2 +/- 22.9 dry to 76.3 +/- 20.5 (P = 0.02) submersed, to 61.6 +/- 13.9 (P < 0.001) at 4.7 ATA during air breathing and to 49.2 +/- 7.3 (P < 0.001) during breathing with resistance. We conclude that the major contributors to increased Pa(CO(2)) during exercise at 4.7 ATA are increased depth and external respiratory resistance. HCVR and maximal O(2) consumption were also weakly predictive. The effects of P(tr), inspired Po(2), and O(2) consumption during short-term exercise were not significant.
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Affiliation(s)
- A D Cherry
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
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Pilolla KD, Bryant TK, Manore MM, Donatelle RJ, Jabson JM, Walker AJ, Ourada VE. A pilot study: Impact of a non‐weight loss intervention, focused on changing diet and physical activity (PA) behaviors, in midlife women at risk for metabolic syndrome (MetS). FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.677.20] [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: 11/11/2022]
Affiliation(s)
| | | | | | | | | | - A J Walker
- Human Development & Family SciencesOregon State UniversityCorvallisOR
| | - V E Ourada
- Human Development & Family SciencesOregon State UniversityCorvallisOR
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18
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Walker AJ. Care of the critically III patient in the tropics and sub-tropics. D. A. K. Watters, I. H. Wilson, R. J. Leaver and A. Bagshawe. 235 × 15.5 mm. Pp. 450 + xiv. Illustrated. 1991. Busingstoke: Macmillan Education. £40. Br J Surg 2005. [DOI: 10.1002/bjs.1800790539] [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: 11/08/2022]
Affiliation(s)
- A J Walker
- The Royal Infirmary, Edinburgh EH3 9YW, UK
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19
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Walker AJ. War wounds of the limbs: Surgical management. R. M. Coupland (ed.). 195 × 253 mm. Pp. 101. Illustrated. 1993. Oxford: Butterworth–Heinemann. £30. Br J Surg 2005. [DOI: 10.1002/bjs.1800810566] [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: 11/10/2022]
Affiliation(s)
- A J Walker
- Royal Naval Hospital, Plymouth PL1 3JY, UK
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Affiliation(s)
- A J Walker
- Surgical Professorial Unit, St. Bartholomew's Hospital
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21
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Abstract
This is a review of our experience with vascular access procedures over a 5-year period at Derriford Hospital, Plymouth, UK. The aims of the study were to examine the outcome of vascular access procedures and factors influencing access survival. Between April 1995 and March 2000, 151 patients who underwent 221 vascular access procedures were studied. Of these, 136 had autogenous arteriovenous fistulae, whereas 85 had prosthetic AV grafts (41% in the thigh). The overall primary failure rate was 21% whereas the 1- and 5-year cumulative access survival rates were 60 and 41%, respectively. Thigh grafts have a mean survival of 36 months compared with 32 months for prosthetic upper limb and 43 months for autogenous fistulae. Age, diabetes and predialysis status did not significantly influence access survival. Thrombosis was responsible for access failure in 62 cases (28%). Avoiding subclavian vein canulation and performing vessel mapping prior to access placement should reduce the risk of access failure due to outflow obstruction.
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Affiliation(s)
- J A Akoh
- Department of Renal Medicine, Plymouth Hospitals NHS Trust, Derriford Hospital, Plymouth, UK.
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22
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Bisseling TM, Steegers EAP, van den Heuvel JJM, Siero HLM, van de Water FM, Walker AJ, Steegers-Theunissen RPM, Smits P, Russel FGM. Placental folate transport and binding are not impaired in pregnancies complicated by fetal growth restriction. Placenta 2004; 25:588-93. [PMID: 15135243 DOI: 10.1016/j.placenta.2003.11.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [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] [Received: 04/15/2003] [Revised: 11/21/2003] [Accepted: 11/27/2003] [Indexed: 11/22/2022]
Abstract
Maternal folate deficiency is associated with fetal growth restriction, however, transfer of folate across placentae of pregnancies complicated by fetal growth restriction has never been investigated. We studied whether maternal to fetal 5-methyltetrahydrofolate (5MTF) transport in the ex vivo dually perfused isolated cotyledon, binding of [(3)H] folate (PteGlu) to the syncytial microvillous membrane, and protein expression of folate receptor alpha (FR-alpha) and reduced folate carrier (RFC) in these placentae are disturbed. Placental clearance of 5MTF from the maternal perfusate appeared to be non-saturable over a range of 50 to 500 nm, independent of albumin and flow-independent. No statistically significant differences between placentae complicated with fetal growth restriction and uncomplicated pregnancies were observed. Binding characteristics of [(3)H-]PteGlu to microvillous membranes of fetal growth restriction versus control placentae were similar: B(max)of 3.9+/-2.0 (mean+/-s.d.) versus 4.0+/-1.6 pmol/mg protein and a K(d)of 0.037+/-0.010 versus 0.040+/-0.018 nm. Expression of FR-alpha and RFC were not different in placentae of both groups studied. In conclusion, fetal growth restriction appears not to be associated with impaired maternal to fetal placental folate transport, placental receptor binding, or expression of FR-alpha and RFC.
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Affiliation(s)
- T M Bisseling
- Department of Pharmacology and Toxicology, University Medical Centre Nijmegen, 233, University Medical Centre Nijmegen/NCMLS, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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23
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Lambert AW, Dashfield A, Cosgrove C, Wilkins DC, Walker AJ, Ashley S. Randomized prospective study comparing pre-emptive epidural and intraoperative perineural analgesia for the prevention of postoperative stump and phantom limb pain following major amputation. Br J Surg 2002. [DOI: 10.1046/j.1365-2168.2000.01420-62.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Background
The reported incidence of phantom limb pain (PLP) following amputation is up to 85 per cent. This study was designed to compare the efficacy of two perioperative analgesic techniques with respect to postoperative stump pain (POSP) and PLP.
Methods
Patients were randomized prospectively. Group 1 received a pre-emptive epidural for a minimum of 24 h before surgery which was continued after operation. Group 2 had intraoperative placement of a perineural catheter for the administration of local anaesthetic by infusion after operation. All amputations were performed under general anaesthesia. POSP was assessed by visual analogue score (VAS), ranging from 0 to 10. The presence of PLP was assessed 6 and 12 months after operation.
Results
A total of 30 patients were recruited, 12 men and 18 women, of median age 74 (range 47–93) years. Each group was well matched for concurrent cardiovascular disease and the level of amputation. VAS at 6 h, 1, 2 and 3 days after operation was significantly less in group 1 than group 2 (P < 0·05, two-sample t test). Six patients died in each group and one was lost to follow-up. The overall incidence of PLP was 75 per cent at 6 months and 44 per cent at 12 months, with no significant difference between the two groups.
Conclusion
In this series, pre-emptive epidural analgesia significantly reduced the severity of POSP. The incidence of PLP remains disappointingly high regardless of the analgesic technique used.
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Affiliation(s)
- A W Lambert
- Vascular Surgical Unit, Derriford Hospital, Plymouth, UK
| | - A Dashfield
- Department of Anaesthesia, Derriford Hospital, Plymouth, UK
| | - C Cosgrove
- Vascular Surgical Unit, Derriford Hospital, Plymouth, UK
| | - D C Wilkins
- Vascular Surgical Unit, Derriford Hospital, Plymouth, UK
| | - A J Walker
- Vascular Surgical Unit, Derriford Hospital, Plymouth, UK
| | - S Ashley
- Vascular Surgical Unit, Derriford Hospital, Plymouth, UK
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Gaskill SE, Walker AJ, Serfass RA, Bouchard C, Gagnon J, Rao DC, Skinner JS, Wilmore JH, Leon AS. Changes in ventilatory threshold with exercise training in a sedentary population: the HERITAGE Family Study. Int J Sports Med 2001; 22:586-92. [PMID: 11719894 DOI: 10.1055/s-2001-18522] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
UNLABELLED The purpose of this study was to evaluate the effect of exercise training intensity relative to the ventilatory threshold (VT) on changes in work (watts) and VO2 at the ventilatory threshold and at maximal exercise in previously sedentary participants in the HERITAGE Family Study. We hypothesized that those who exercised below their VT would improve less in VO2 at the ventilatory threshold (VO2vt) and VO2max than those who trained at an intensity greater than their VT. Supervised cycle ergometer training was performed at the 4 participating clinical centers, 3 times a week for 20 weeks. Exercise training progressed from the HR corresponding to 55% VO2max for 30 minutes to the HR associated with 75% VO2max for 50 minutes for the final 6 weeks. VT was determined at baseline and after exercise training using standardized methods. 432 sedentary white and black men (n = 224) and women (n = 208), aged 17 to 65 years, were retrospectively divided into groups based on whether exercise training was initiated below, at, or above VT. RESULTS 1) Training intensity (relative to VT) accounting for about 26% of the improvement in VO2vt (R2 = 0.26, p < 0.0001). 2) The absolute intensity of training in watts (W) accounted for approximately 56% of the training effect at VT (R2 = 0.56, p < 0.0001) with post-training watts at VT (VT(watts)) being not significantly different than W during training (p > 0.70). 3) Training intensity (relative to VT) had no effect on DeltaVO2max. These data clearly show that as a result of aerobic training both the VO2 and W associated with VT respond and become similar to the absolute intensity of sustained (3 x /week for 50 min) aerobic exercise training. Higher intensities of exercise, relative to VT, result in larger gains in VO2vt but not in VO2max.
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Affiliation(s)
- S E Gaskill
- Department of Health and Human Performance, Human Performance Laboratory, University of Montana, Missoula, MT 59812, USA.
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Gaskill SE, Ruby BC, Walker AJ, Sanchez OA, Serfass RC, Leon AS. Validity and reliability of combining three methods to determine ventilatory threshold. Med Sci Sports Exerc 2001; 33:1841-8. [PMID: 11689733 DOI: 10.1097/00005768-200111000-00007] [Citation(s) in RCA: 244] [Impact Index Per Article: 10.6] [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: 11/25/2022]
Abstract
PURPOSE This research was undertaken to validate a combination of methodologies to determine ventilatory threshold (VT). METHODS Three methods were used individually and then combined to determine VT as follows: 1) ventilatory equivalencies, 2) excess CO2 production, and 3) a modified V-slope method. Three groups of participants-endurance athletes (N = 132), healthy, aerobically active adults (N = 31), and healthy, sedentary/low-active adults (N = 22)-were independently evaluated for VT and compared with the criterion standard lactate threshold (LT) defined as the first rise in blood lactate with increasing intensity of exercise. RESULTS VT and LT were significantly correlated using the combined VT method within each study group (r = 0.98, 0.97, and 0.95, respectively; P < 0.001). Mean VO2 values at VT and LT were not significantly different between the three groups (P > 0.20). The combined method improved the determination rate of VT and reduced the standard deviation of the LT - VT difference by 80-170% over the individual methods. During test-retest procedures VO2lt and VO2vt determined by the combined method met criteria demonstrating further reliability. CONCLUSION The combined method to determine VT is valid and reliable across a wide fitness range in healthy individuals and improves the determination rate and accuracy of VT determination over the use of single methods.
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Affiliation(s)
- S E Gaskill
- Human Performance Laboratory, Department of Health and Human Performance, University of Montana, Missoula, MT 59812, USA.
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26
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Chapman TW, Bowley DM, Lambert AW, Walker AJ, Ashley SA, Wilkins DC. Haemorrhage associated with combined clopidogrel and aspirin therapy. Eur J Vasc Endovasc Surg 2001; 22:478-9. [PMID: 11735194 DOI: 10.1053/ejvs.2001.1506] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Avery MD, Walker AJ. Acute effect of exercise on blood glucose and insulin levels in women with gestational diabetes. J Matern Fetal Med 2001; 10:52-8. [PMID: 11332421 DOI: 10.1080/714904296] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
OBJECTIVE To evaluate the effect of a single session of exercise (cycling), at rest (control condition) and at two intensity levels (low- and moderate-intensity exercise conditions), on blood glucose and insulin in pregnancy complicated by gestational diabetes mellitus (GDM). METHODS A one-group repeated measures design was used. Women aged 18-38 with GDM, no other complications, not on insulin, and not exercising regularly were recruited. The women rested or exercised at the two intensities for 30 min and rested for 2 h after each session. Blood was sampled for blood glucose, insulin and hematocrit at baseline and every 15 min. RESULTS There was no difference at baseline in blood glucose levels. The blood glucose level was significantly lower for each exercise condition compared to rest, and for moderate compared to low-intensity exercise (5.2 vs. 4.3 vs 3.9 mmol/l) at the end of exercise (30 min), and for the two exercise conditions compared to rest at 15 min after exercise (4.9 vs 4.4 vs. 4.0 mmol/l). By 45 min after exercise, the blood glucose values were nearly identical. The area under the curve for blood glucose was significantly lower for low- and moderate-intensity exercise than for rest (p = 0.01). The slope of change in insulin among the three conditions, from baseline to the 30-min session, approached significance (p = 0.065). The power for that analysis was 0.51. A sample of 23 would have been required to increase the power to 0.80. CONCLUSIONS Significant declines in blood glucose level were observed during low- and moderate-intensity exercise compared to rest. These differences were gone by 45 min after exercise. Continued research should examine those with high body mass index and more pronounced hyperglycemia for further evaluation of the effect of exercise on blood glucose and insulin levels in women with GDM.
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Affiliation(s)
- M D Avery
- School of Nursing, University of Minnesota, Minneapolis 55455, USA.
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Walker AJ, Draeger A, Houssa B, van Blitterswijk WJ, Ohanian V, Ohanian J. Diacylglycerol kinase theta is translocated and phosphoinositide 3-kinase-dependently activated by noradrenaline but not angiotensin II in intact small arteries. Biochem J 2001; 353:129-137. [PMID: 11115406 PMCID: PMC1221550] [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
Diacylglycerol (DG) kinase (DGK) phosphorylates the lipid second messenger DG to phosphatidic acid. We reported previously that noradrenaline (NA), but not angiotensin II (AII), increases membrane-associated DGK activity in rat small arteries [Ohanian and Heagerty (1994) Biochem. J. 300, 51-56]. Here, we have identified this DGK activity as DGKtheta, present in both smooth muscle and endothelial cells of these small vessels. Subcellular fractionation of artery homogenates revealed that DGKtheta was present in nuclear, plasma membrane (and/or Golgi) and cytosolic fractions. Upon NA stimulation, DGKtheta translocated towards the membrane and cytosol (155 and 153% increases relative to the control, respectively) at 30 s, followed by a return to near-basal levels at 5 min; AII was without effect. Translocation to the membrane was to both Triton-soluble and -insoluble fractions. NA, but not AII, transiently increased DGKtheta activity in immunoprecipitates (126% at 60 s). Membrane translocation and DGKtheta activation were regulated differently: NA-induced DGKtheta activation, but not translocation, was dependent on transient activation of phosphoinositide 3-kinase (PI 3-K). In addition, DGK activity co-immunoprecipitated with protein kinase B, a downstream effector of PI 3-K, and was increased greatly by NA stimulation. The rapid and agonist-specific activation of DGKtheta suggests that this pathway may have a physiological role in vascular smooth-muscle responses.
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MESH Headings
- Androstadienes/pharmacology
- Angiotensin II/pharmacology
- Animals
- Arteries/cytology
- Arteries/drug effects
- Arteries/enzymology
- Arteries/metabolism
- Arterioles/cytology
- Arterioles/drug effects
- Arterioles/enzymology
- Arterioles/metabolism
- Cell Membrane/drug effects
- Cell Membrane/enzymology
- Cell Membrane/metabolism
- Cells, Cultured
- Cytosol/drug effects
- Cytosol/enzymology
- Cytosol/metabolism
- Diacylglycerol Kinase/metabolism
- Dose-Response Relationship, Drug
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/metabolism
- Enzyme Activation/drug effects
- Female
- Immunohistochemistry
- In Vitro Techniques
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- Norepinephrine/agonists
- Norepinephrine/pharmacology
- Phosphatidylinositol 3-Kinases/metabolism
- Phosphoinositide-3 Kinase Inhibitors
- Precipitin Tests
- Protein Binding
- Protein Serine-Threonine Kinases
- Protein Transport/drug effects
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Rats
- Rats, Sprague-Dawley
- Wortmannin
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Affiliation(s)
- A J Walker
- Department of Medicine, University of Manchester, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK
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29
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Kingsnorth AN, Porter CS, Bennett DH, Walker AJ, Hyland ME, Sodergren S. Lichtenstein patch or Perfix plug-and-patch in inguinal hernia: a prospective double-blind randomized controlled trial of short-term outcome. Surgery 2000; 127:276-83. [PMID: 10715982 DOI: 10.1067/msy.2000.104124] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [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: 01/13/2023]
Abstract
BACKGROUND Open mesh used in anterior inguinal hernia repair can be configured as a flat patch (Lichtenstein operation) or as a cone-shaped preformed plug and supplementary patch (plug-and-patch operation; Perfix Plug; Davol Inc, Cranston, RI). METHODS One hundred forty-one patients were randomly allocated and blinded to receive either a Lichtenstein patch or a Perfix plug-and-patch. Information before the operation and on postoperative days 3 and 14 was recorded by an independent blinded observer to include operating time, postoperative pain, analgesic medication, return to activity and work, and quality of life assessment. RESULTS Operating time (32 vs 37.6 minutes) was significantly shorter in the plug-and-patch group (P = .01). During days 1 through 8, patients who had undergone the plug-and-patch operation experienced less pain, and their physical functioning on day 3 was significantly better (P = .013). Days of analgesic medication (4.0 vs 4.6 days), return to normal activity (2.8 vs 3.6 days), return to work (17.0 vs 20.8 days), and total days of work missed (14.3 vs 16.1 days) were similar in both groups (P = NS for all comparisons). CONCLUSIONS Compared with patients who received the Lichtenstein patch for ambulatory inguinal hernia repair, patients who underwent the Perfix plug-and-patch operation experienced less postoperative pain in the first 8 days after the operation but consumed similar postoperative analgesic medication. The rate of return to normal activity and work is similar in both groups, which indicates no superiority for the plug-and-patch operation in overall rehabilitation and societal costs. Overall hospital costs are greater for the plug-and-patch operation ($120 [US]) compared with the Lichtenstein patch ($20 [US]), with a negligible (5.6 minutes) saving of operating room time for the plug-and-patch operation.
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Affiliation(s)
- A N Kingsnorth
- Department of Surgery, Postgraduate Medical School, University of Plymouth, England
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Abstract
The neuropsychological functioning of adults with Attention Deficit Hyperactivity Disorder (ADHD) was compared to that of healthy controls and individuals with mild psychiatric disorders including attentional complaints. Thirty adults in each group were examined on the Conners' Continuous Performance Test (CPT) and measures of attention, executive function, psychomotor speed, and arithmetic skills. The ADHD group performed lower than healthy controls on most measures. However when compared to the psychiatric group, the performances of the ADHD group were not significantly lower on any of the measures. The predictive power of the tests was poor in discriminating ADHD from psychiatric disorder. Implications for the clinical diagnosis of ADHD are discussed.
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Affiliation(s)
- A J Walker
- Neuropsychiatric Institute, Prince of Wales Hospital, Sydney, Australia.
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Abstract
BACKGROUND Medical research produces large multivariable datasets that are difficult to visualise and interpret intuitively. We describe a novel growing cell structure (GCS) technique that compresses multidimensional datasets into two dimensional maps with colour overlays that can be visually interpreted. METHODS The two-dimensional map is self-discovered from the training set by distribution of cases to different nodes according to similarity between the cases at each node. Nodes are added to the map until there is no further significant reduction in error. The Parzen window method is used to estimate the probability distribution of the training cases, and this probability is converted to posterior class probabilities by use of Bayes' theorem. Classification performance can be assessed by means of receiver operating characteristic (ROC) curves. Colour maps of the values of each input variable at each node are constructed, which illustrate the relation between each input variable and the overall distribution of cases in the network map. FINDINGS From a dataset of 11 input variables from 692 fine-needle aspirate samples from breast lesions, a 32-node network produced an area under the ROC curve of 0.96, which was not significantly different from that for logistic regression (0.98, z=1.09, p>0.05). Colour maps of the input variables showed that some variables had discrete distributions over exclusively benign or malignant areas of the network, and were thus discriminant, whereas others, such as foamy macrophages, covered both benign and malignant regions. INTERPRETATION This technique produces dimensional compression that allows multidimensional data to be displayed as two-dimensional colour images. This envisioning of information allows the highly developed visuospatial abilities of human observers to perceive subtle inter-relations in the dataset.
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Affiliation(s)
- A J Walker
- Department of Automatic Control and Systems Engineering, University of Sheffield, UK
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Walker AJ, Urwin PE, Atkinson HJ, Brain P, Glen DM, Shewry PR. Transgenic Arabidopsis leaf tissue expressing a modified oryzacystatin shows resistance to the field slug Deroceras reticulatum (Müller). Transgenic Res 1999; 8:95-103. [PMID: 10481309 DOI: 10.1023/a:1008814317199] [Citation(s) in RCA: 30] [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: 11/12/2022]
Abstract
Transgenic Arabidopsis thaliana has been developed which expresses the oryzacystatin mutant OC-I delta 86, which is an inhibitor of the major proteinase present in the digestive gland of the slug, Deroceras reticulatum. When fed on leaf tissue from plants expressing this inhibitor the growth of juvenile slugs was significantly reduced by 31% compared with those feeding on control leaf tissue. Furthermore, while surviving slugs did not individually consume less when feeding on leaf tissue expressing OC-I delta 86, the total amount of leaf tissue eaten was 50% less, due to reduced survival of slugs. The synthetic cysteine proteinase inhibitors E-64 and leupeptin also significantly reduced slug weight gain (by at least 40%) and digestive gland cysteine proteinase activity when administered in an artificial diet, indicating that their antimetabolic effects are due to direct inhibition of gut proteolytic activity. These results suggest that transgenic crop plants expressing phytocystatins could be used to suppress the growth rates of slug populations in the field.
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Affiliation(s)
- A J Walker
- IACR-Long Ashton Research Station, Department of Agricultural Sciences, University of Bristol, UK.
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Prance SE, Wilson YG, Cosgrove CM, Walker AJ, Wilkins DC, Ashley S. Ruptured abdominal aortic aneurysms: selecting patients for surgery. Eur J Vasc Endovasc Surg 1999; 17:129-32. [PMID: 10063407 DOI: 10.1053/ejvs.1998.0718] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES Mortality from ruptured abdominal aortic aneurysm (RAAA) remains high. Despite this, withholding surgery on poor-prognosis patients with RAAA may create a difficult dilemma for the surgeon. Hardman et al. identified five independent, preoperative risk factors associated with mortality and proposed a model for preoperative patient selection. The aim of this study was to test the validity of the same model in an independent series of RAAA patients. METHODS A consecutive series of patients undergoing surgery for RAAA was analysed retrospectively by case-note review. Thirty-day operative mortality and the presence of the five risk factors: age (> 76 years), creatinine (Cr) (> 190 mumol/l), haemoglobin (Hb) (< 9 g/dl), loss of consciousness and electrocardiographic (ECG) evidence of ischaemia were recorded for each patient. RESULTS Complete data sets existed for 69 patients (mean age: 73 years, range: 38-86 years, male to female ratio: 6:1). Operative mortality was 43%. The cumulative effect of 0, 1 and 2 risk factors on mortality was 18%, 28% and 48%, respectively. All patients with three or more risk factors died (eight patients). CONCLUSIONS These results lend support to the validity of the model. The potential to avoid surgery in patients with little or no chance of survival would spare unnecessary suffering, reduce operative mortality and enhance use of scarce resources.
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Affiliation(s)
- S E Prance
- Vascular Surgical Unit, Derriford Hospital, Plymouth, U.K
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Bassett DR, Duey WJ, Walker AJ, Torok DJ, Howley ET, Tanaka H. Exaggerated blood pressure response to exercise: importance of resting blood pressure. Clin Physiol 1998; 18:457-62. [PMID: 9784942 DOI: 10.1046/j.1365-2281.1998.00124.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Normotensive individuals who exhibit an exaggerated blood pressure (BP) response to exercise have an increased risk of future hypertension. However, previous studies failed to control for resting BP despite the fact that an elevated resting BP in the normotensive range is also a strong predictor of future hypertension. Therefore, we determined whether maximal systolic BP is associated with resting BP. Resting BP was measured in 68 healthy normotensive men on three separate days. The subjects then performed a graded, maximal exercise test on a Monark cycle ergometer. Maximal systolic BP was strongly correlated with resting systolic BP (r = 0.64, P < 0.0001). Subjects with elevations in systolic BP during maximal exercise (> 220 mmHg) also had higher (P < 0.005) resting BP than those without (< 220 mmHg). When stepwise regression analyses were performed, systolic BP at rest was a significant independent predictor of maximal systolic BP, explaining over 40% of the variability. These results suggest that exaggerated BP response as a predictor of future hypertension reported in previous studies may be little more than a simple reflection of elevated resting BP. Specifically, these studies should not be interpreted as demonstrating that exercise BP is a better predictor of future hypertension than resting BP alone. In the future, defining the BP 'response' to exercise as a change score (i.e. maximal BP minus resting BP) may be advantageous as it permits the effects of exercise to be examined independently of the level of resting BP.
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Affiliation(s)
- D R Bassett
- Exercise Science Unit, University of Tennessee, Knoxville, USA
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Affiliation(s)
- L Cannon
- Vascular Unit, Derriford Hospital, Plymouth, U.K
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36
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Moiseenko VV, Walker AJ, Prestwich WV. Energy deposition pattern from tritium and different energy photons--a comparative study. Health Phys 1997; 73:388-392. [PMID: 9228177 DOI: 10.1097/00004032-199708000-00014] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Energy deposition patterns of beta particles from tritium decay have been analyzed in comparison with photon radiation in the energy range from 12 to 1250 keV. Energy deposition was modeled by Monte Carlo means using electron tracks in water vapor with a complete follow up of delta electrons. Ionizations have been used as representative of track structure. Frequencies of clusters on a nanometer scale and their spatial distribution in spherical targets representing cell nuclei have been derived. Cluster analysis has been carried out by implementing a k-means method. Frequencies of ionization clusters from tritium are similar to 60-100 keV photons. Spatial distribution of clusters from tritium closely match approximately 70 keV photons up to 2 microm separation.
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Affiliation(s)
- V V Moiseenko
- McMaster University, Department of Physics and Astronomy, Hamilton, Ontario, Canada
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Duey WJ, Bassett DR, Walker AJ, Torok DJ, Howley ET, Ely D, Pease MO. Cardiovascular and plasma catecholamine response to static exercise in normotensive blacks and whites. Ethn Health 1997; 2:127-136. [PMID: 9395595 DOI: 10.1080/13557858.1997.9961821] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
OBJECTIVES The objectives of the present study were (1) to evaluate the pressor response to an isometric handgrip exercise in normotensive black and white males; (2) to measure plasma catecholamine levels pre- and post-exercise, as an index of sympathetic nervous system activity; and (3) to quantify the pressor response to bolus intravenous injections of phenylephrine (an alpha-specific agonist). METHODS Cardiovascular and catecholamine responses to an isometric handgrip exercise (3 minutes at 30% MVC) were measured in 15 normotensive blacks and whites. In another phase of the study, pressor responses to bolus injections of phenylephrine were assessed to evaluate alpha-adrenergic sensitivity. RESULTS The blood pressure in the blacks increased from 119/69 to 160/120 mm HG during isometric exercise, while in the whites it increased from 118/67 to 153/110 mm HG. The blacks exhibited a greater diastolic blood pressure reactivity, as evidenced by a significant race x time interaction (p < 0.05). The heart rate responses were not significantly different between the two groups. The plasma levels of norepinephrine were similar at rest, but were 25% lower in the blacks than in the whites following isometric exercise (p < 0.01). Black subjects also demonstrated an increased pressor response to intravenous injections of phenylephrine at rest (p < 0.05). CONCLUSIONS The enhanced vascular sensitivity to norepinephrine may have contributed to the greater exercise pressor response in the blacks.
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Affiliation(s)
- W J Duey
- Exercise Science Unit, University of Tennessee-Knoxville, USA
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Rose JD, Walker AJ. Traumatic diaphragmatic herniation. J R Nav Med Serv 1997; 82:197-8. [PMID: 9167360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- J D Rose
- Department of Plastic Surgery at MDHU Derriford
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Abstract
We examined the wear-and-tear hypothesis using data from 4 annual interviews with 130 (128 White) middle-aged daughters caring for their physically impaired, elderly mothers. We formulated a latent growth curve model hypothesizing that increases in the amount of care given by daughters caused a decrease in caregiving satisfaction, independent of caregiving duration. We found considerable individual variability and change in both caregiving satisfaction and the amount of care given in univariate latent growth curve analyses. Contrary to the wear-and-tear hypothesis, a multivariate latent growth curve analysis revealed duration of caregiving had no effect on either initial caregiving satisfaction or change in satisfaction. An elaborated wear-and-tear model was supported, however. The mechanism for decline in satisfaction is an increase in the amount of care given.
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Affiliation(s)
- A J Walker
- Department of Human Development and Family Sciences, Oregon State University, USA.
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Bassett, Walker AJ, Duey WJ, Howley ET. 462 THE EXAGGERATED BLOOD PRESSURE (BP) RESPONSE TO EXERCISE: DOES IT PREDICT FUTURE HYPERTENSION? Med Sci Sports Exerc 1994. [DOI: 10.1249/00005768-199405001-00463] [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: 11/21/2022]
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Bracker JS, Sussman L, Walker AJ. Creating a high-performance team through proactive management. Clin Lab Manage Rev 1994; 8:269-74. [PMID: 10134739] [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
Numerous articles, business consultants, and scholars argue that high-performing management teams lead to higher productivity in organizations. Unfortunately, few managers are able to successfully develop such teams in their organizations. This article outlines the five strategies that define proactive management and produce high-performing teams.
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Bradbury AW, Stonebridge PA, Callam MJ, Walker AJ, Allan PL, Beggs I, Ruckley CV. Recurrent varicose veins: assessment of the saphenofemoral junction. Br J Surg 1994; 81:373-5. [PMID: 8173902 DOI: 10.1002/bjs.1800810316] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Thirty-six consecutive unselected patients, who had apparently previously undergone saphenofemoral ligation for primary uncomplicated long saphenous varicosities and who had then re-presented with recurrent thigh varices emanating from the groin, underwent preoperative clinical assessment, hand-held Doppler and duplex ultrasonographic examination and varicography to establish the presence or absence of saphenofemoral incompetence as the cause of recurrence. All patients underwent reexploration of the saphenofemoral junction (SFJ) via a lateral approach. Twenty-six patients had an intact SFJ (type I recurrence) and ten had varices arising from either a thigh perforator, or from abdominal or perineal veins (type II recurrence). Clinical examination alone was poor at distinguishing type I from type II recurrence. Doppler ultrasonography was sensitive (88 per cent) but non-specific (40 per cent). In contrast, duplex scanning was insensitive (42 per cent) but extremely specific (100 per cent) and accurate, with a positive predictive value of 100 per cent. Varicography also had a specificity and positive predictive value of 100 per cent, a sensitivity of 73 per cent and in addition provided a precise anatomical 'road-map'. A combination of clinical examination and hand-held Doppler ultrasonography seems to be the most appropriate first-line method of preoperative assessment in these patients. Duplex ultrasonography, if available, will provide additional useful information about both the SFJ and the presence of thigh perforators. Contrast examination may be reserved for patients who have equivocal results on non-invasive investigations, who have had more than one previous groin operation or who have, in addition, deep venous disease.
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Affiliation(s)
- A W Bradbury
- University Department of Clinical Surgery, Royal Infirmary, Edinburgh, UK
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Abstract
After vascular injury, intraluminal arterial shunting may be employed if definitive surgery must be delayed. This paper describes use of a heparin-bonded polyurethane shunt to restore distal circulation after ligation of the femoral artery in sheep. In studies to determine tissue viability for 12 h after insertion into the femoral artery, five of seven shunts remained patent. In another series of experiments to study tissue viability after limb ischaemia, the femoral artery was ligated and a tight Esmarch bandage applied to the limb for 6 h before shunt insertion. The shunt remained patent for 12 h in five of six cases. Nearly all shunt failures occurred shortly after placement and were attributable to intimal damage arising from difficulties during insertion.
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Affiliation(s)
- A J Walker
- Medical Division, Chemical and Biological Defence Establishment, Porton Down, Salisbury, UK
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Bond V, Bassett DR, Howley ET, Lewis J, Walker AJ, Swan PD, Tearney RJ, Adams RG. Evaluation of the Colin STBP-680 at rest and during exercise: an automated blood pressure monitor using R-wave gating. Br J Sports Med 1993; 27:107-9. [PMID: 8358579 PMCID: PMC1332130 DOI: 10.1136/bjsm.27.2.107] [Citation(s) in RCA: 9] [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] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The application of automated blood pressure measurement during exercise has been limited by inaccuracies introduced by the effects of accompanying motion and noise. We evaluated a newly developed automated blood pressure monitor for measuring exercise blood pressure (Colin STBP-680; Colin, San Antonio, Texas, USA). The STBP-680 uses acoustic transduction with the assistance of the electrocardiogram R-wave to trigger the sampling period for blood pressure measurement. The automated monitor readings were compared with simultaneous technician mercury sphygmomanometric readings in the same arm. Blood pressure was measured in 18 men at rest and during exercise at 40% VO2 peak, (low intensity), 70% VO2 peak (moderate intensity) and VO2 peak (high intensity) on the cycle ergometer. Mean(s.d.) systolic blood pressure difference between the automated monitor and mercury manometer readings at rest and during exercise at low, moderate and high work intensities were 3(0) mmHg, 3(2) mmHg, 1(1) mmHg, and 0(11) mmHg respectively (analysis of variance; P > 0.05). Resting diastolic blood pressure obtained with the STBP-680 was similar to the mercury manometer readings (78(10) versus 81(7) mmHg (P > 0.05). Exercise diastolic pressure at the low level of work intensity was almost identical between the automated monitor and mercury manometer readings (64(8) versus 65(10) mmHg (not significant)). Diastolic blood pressure readings between the STBP-680 and mercury manometer showed a greater difference at the moderate and high workloads (11 mmHg and 9 mmHg, respectively), but this difference was not significant (P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- V Bond
- Department of Human Performance and Sport Studies, University of Tennessee, Knoxville
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Abstract
Over a 7-month period 50 patients presented to the vascular unit with a ruptured or acute symptomatic abdominal aortic aneurysm (AAA). Information regarding the 24 months before acute presentation was obtained from the patient, family doctor and relevant case records to determine whether an asymptomatic aneurysm had previously been diagnosed but the patient not referred to the vascular service, or whether the patient had undergone an examination at which an aneurysm might reasonably have been expected to be diagnosed. Thirteen patients (26 per cent) had previously had an AAA diagnosed but only five had been referred. Thirteen patients (26 per cent) had had a total of 16 inpatient hospital admissions without an asymptomatic aneurysm being diagnosed. Six patients (12 per cent) underwent abdominal examination for an unrelated complaint by the family doctor without an asymptomatic aneurysm being diagnosed. A significant impact on overall mortality from aortic aneurysm may be made by increasing the number of patients undergoing elective aneurysm repair. All doctors should assess aortic diameter in all patients over 50 years of age who undergo abdominal examination for whatever reason. All patients diagnosed as having an asymptomatic AAA should be referred to a vascular surgeon for assessment.
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Affiliation(s)
- S R Craig
- Department of Vascular Surgery, Royal Infirmary, Edinburgh, UK
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Bassett DR, Duey WJ, Walker AJ, Howley ET, Bond V. Racial differences in maximal vasodilatory capacity of forearm resistance vessels in normotensive young adults. Am J Hypertens 1992; 5:781-6. [PMID: 1457077 DOI: 10.1093/ajh/5.11.781] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [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: 12/27/2022] Open
Abstract
This study was performed to determine whether alterations in vascular structure exist in a biracial population of young (age 22.3 +/- 0.6 yrs [mean + SE]) normotensive men. We examined maximal vasodilatory capacity in 21 blacks and 20 whites (average blood pressure = 122/75 and 118/72 mm Hg, respectively). Forearm blood flow was determined at rest and after 10 min of ischemic handgrip exercise using venous occlusion plethysmography. Forearm vascular resistance was computed from blood flow and mean arterial blood pressure determined by auscultation. Minimum forearm vascular resistance was 23% higher in blacks (2.60 +/- 0.60) than in whites (2.11 +/- 0.41) (P = .005), and was unrelated to parental history of hypertension. The regression equation for minimum forearm vascular resistance (Y) and casual blood pressure (X) for blacks was Y = -1.782 + 0.0487X (r = 0.522); for whites it was Y = -1.165 + 0.0367X (r = 0.418). When the data were covaried on resting mean arterial blood pressure, blacks still had a higher minimum forearm vascular resistance (P = .014). The results suggest a racial difference in the vascular structure of the forearm resistance vessels.
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Affiliation(s)
- D R Bassett
- Department of Human Performance and Sport Studies, University of Tennessee-Knoxville 37996
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Walker AJ, Bassett DR, Duey WJ, Howley ET, Bond V, Torok DJ, Mancuso P. Cardiovascular and plasma catecholamine responses to exercise in blacks and whites. Hypertension 1992; 20:542-8. [PMID: 1398889 DOI: 10.1161/01.hyp.20.4.542] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The purpose of the present study was to assess possible racial differences in cardiovascular and plasma catecholamine responses to dynamic exercise. A biracial group of normotensive college-age men (15 blacks, 15 whites) were tested for maximal oxygen uptake, resting blood pressure, and heart rate. Subjects then rode a cycle ergometer at 25%, 50%, and 75% of peak oxygen uptake (6 minutes at each stage). Blood pressure and heart rate were measured during supine rest, seated rest, and at each stage of exercise with an automated blood pressure monitor. At each stage, venous blood was sampled to allow determination of plasma norepinephrine and epinephrine, and cardiac output was measured with the carbon dioxide rebreathing technique. The results indicated that resting blood pressure was similar for blacks and whites (114/68 versus 115/68 mm Hg, respectively). Blacks exhibited greater systolic and diastolic blood pressures during submaximal dynamic exercise. However, blacks also showed a trend toward a positive parental history of hypertension, which has been associated with an increased pressor response. Racial differences did not exist for heart rate or cardiac output, but blacks had higher values for total peripheral resistance both at rest and during exercise. Although no overall racial differences were seen for plasma catecholamine concentrations at rest, blacks had significantly lower levels of norepinephrine (1,275 versus 1,556 pg/ml) and higher levels of epinephrine (306 versus 216 pg/ml) than whites at the highest work rate. The current study confirms the increased pressor response to exercise in normotensive blacks. Blacks had an elevation in total peripheral resistance that was not accompanied by an increase in plasma norepinephrine levels.
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Affiliation(s)
- A J Walker
- Department of Human Performance and Sport Studies, University of Tennessee-Knowville 37996
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Walker AJ, Holah JT, Denyer SP, Stewart GS. The antibacterial activity of Virkon measured by colony growth and bioluminescence of lux recombinant Listeria monocytogenes. Lett Appl Microbiol 1992; 15:80-2. [PMID: 1368422 DOI: 10.1111/j.1472-765x.1992.tb00730.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [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
Concentration exponents for the broad spectrum antimicrobial Virkon were determined for Listeria monocytogenes using both plate counts and bioluminescence measurements; the values of 3.15 and 2.6 indicate a close equivalence between these two measurement procedures. Virkon is an effective biocide for L. monocytogenes at the manufacturer's in-use concentration of 1%.
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Affiliation(s)
- A J Walker
- University of Nottingham, Faculty of Agricultural and Food Sciences, Sutton Bonington, Leicestershire, UK
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Abstract
In accordance with social exchange theory (Thibaut and Kelley, 1959), this study examined the outcomes of caregiving for elderly mothers and their caregiving daughters (N = 141 pairs). Data were gathered through face-to-face interviews. Principal components factor analyses revealed three factors for mothers: Helplessness, Feeling Loved, and Anger; and three factors for daughters: Insufficient Time, Frustration, and Anxiety. Block regressions with an initial block of demographic variables and a second block of situational variables were performed to determine the relative influence of these two sets of independent variables on caregiving outcomes. The regressions revealed limited influence of demographic variables and significant influence of situational variables. Of particular importance for daughters is the role of perceived intimacy with the mother: Daughters with better relationships experience fewer caregiving costs. Mothers' health plays a critical role in the outcomes of care receiving: Mothers in poorer health experience greater helplessness and are less likely to feel loved.
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Affiliation(s)
- A J Walker
- Department of Human Development and Family Sciences, Oregon State University
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Walker AJ, Jassim SA, Holah JT, Denyer SP, Stewart GS. Bioluminescent Listeria monocytogenes provide a rapid assay for measuring biocide efficacy. FEMS Microbiol Lett 1992; 70:251-5. [PMID: 1624105 DOI: 10.1016/0378-1097(92)90706-t] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- A J Walker
- University of Nottingham, Department of Applied Biochemistry and Food Science, Loughborough, UK
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