1
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Anderson KJ, Walker RJ, Lynch JM, Middleton RG. A qualitative evaluation of internet information on hip and knee osteoarthritis. Ann R Coll Surg Engl 2023; 105:729-733. [PMID: 37489520 PMCID: PMC10618034 DOI: 10.1308/rcsann.2023.0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023] Open
Abstract
BACKGROUND Hip and knee arthritis are two of the most common conditions that result in referral to orthopaedic outpatient clinics. Many patients now use the internet to research their condition and to inform their decision about treatment options. This has implications for the process of informed consent. AIM To assess the quality of patient information on the internet regarding hip and knee arthritis. METHODS 'Hip arthritis' and 'Knee arthritis' were entered as search terms into a popular search engine. To adjust for temporal variation, the process was repeated one month and one year later. Of the 200 results analysed, 83 websites met the inclusion criteria. The quality of patient information presented on these websites was assessed using a validated scoring instrument by two independent observers. RESULTS Most websites assessed were of poor quality; nearly half of all websites did not mention any risks or complications associated with surgical intervention for these conditions. CONCLUSIONS As part of their professional obligation to provide a robust process of informed consent, clinicians should be aware of the variable quality of patient information available on the internet. As such, they should be prepared to advise their patients about quality websites where reliable information can be sought.
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Affiliation(s)
| | | | - J M Lynch
- University Hospital Dorset NHS Foundation Trust, UK
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2
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Chan R, Walker RJ, Samaranayaka A, Schollum J. Long-term impact of early non-infectious complications at the initiation of peritoneal dialysis. ARCH ESP UROL 2023; 43:53-63. [PMID: 36325812 DOI: 10.1177/08968608221132647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Early non-infectious complications at initiation of peritoneal dialysis (PD) are a major burden with unknown long-term impacts on individuals. METHODS Prospective multicentre cohort study using univariable and multivariable Cox regression to identity mortality risk and PD discontinuation risk in those with and without non-infectious complications. All individuals commencing PD between 1 January 2014 and 31 December 2018, registered in the New Zealand Peritoneal Dialysis Registry (NZPDR) were followed up to 31 December 2020. Early non-infectious complications defined as functional, catheter-related, exit-site dialysate leak or anatomical leak complications occurring within 30 days of initiation of PD. Primary outcomes were patient survival and time on PD therapy. Secondary outcomes were peritonitis free survival, first PD catheter survival and catheter tunnel infection free survival. RESULTS Of 1596 individuals included in the study, 102 experienced an early non-infectious complication. Multivariable analysis demonstrated these complications were associated with higher risk of overall mortality (hazard ratio (HR) 1.71; 95% confidence interval (CI) 1.21-2.44), PD discontinuation (HR 1.84; 95% CI 1.41-2.41) and first catheter failure (HR 2.89; 95% CI 2.28-3.66). No difference was found for risk of development of first peritonitis episode or catheter tunnel infection. Mortality risk was associated with functional and exit-site dialysate leak complications and continued beyond 180 days. Risk of PD discontinuation and first catheter loss were associated with catheter and functional complications in the first 180 days. CONCLUSION Early non-infectious complications are associated with long-term mortality risk. Further research in risk factors and causes of early non-infectious complications are required.
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Affiliation(s)
- R Chan
- Department of Nephrology, Southern District Health Board, Dunedin, New Zealand
| | - R J Walker
- Department of Nephrology, Southern District Health Board, Dunedin, New Zealand.,Department of Medicine, Dunedin School of Medicine, University of Otago, New Zealand
| | - A Samaranayaka
- Biostatistics Centre, Division of Health Sciences, University of Otago, Dunedin, New Zealand
| | - Jbw Schollum
- Department of Nephrology, Southern District Health Board, Dunedin, New Zealand.,Department of Medicine, Dunedin School of Medicine, University of Otago, New Zealand
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3
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Leader CJ, Wilkins GT, Walker RJ. The effect of spironolactone on cardiac and renal fibrosis following myocardial infarction in established hypertension in the transgenic Cyp1a1Ren2 rat. PLoS One 2021; 16:e0260554. [PMID: 34843581 PMCID: PMC8629264 DOI: 10.1371/journal.pone.0260554] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/11/2021] [Indexed: 11/19/2022] Open
Abstract
AIMS The renin-angiotensin-aldosterone axis plays a key role in mediating cardiac and kidney injury. Mineralocorticoid receptor antagonism has beneficial effects on cardiac dysfunction, but effects are less well quantified in the cardiorenal syndrome. This study investigated cardiac and kidney pathophysiology following permanent surgical ligation to induce myocardial infarction (MI) in hypertensive animals with or without mineralocorticoid receptor antagonism. METHODS Hypertension was induced in adult male Cyp1a1Ren2 rats. Hypertensive animals underwent MI surgery (n = 6), and were then treated daily with spironolactone for 28 days with serial systolic blood pressure measurements, echocardiograms and collection of urine and serum biochemical data. They were compared to hypertensive animals (n = 4), hypertensive animals treated with spironolactone (n = 4), and hypertensive plus MI without spironolactone (n = 6). Cardiac and kidney tissue was examined for histological and immunohistochemical analysis. RESULTS MI superimposed on hypertension resulted in an increase in interstitial cardiac fibrosis (p<0.001), renal cortical interstitial fibrosis (p<0.01) and glomerulosclerosis (p<0.01). Increased fibrosis was accompanied by myofibroblast and macrophage infiltration in the heart and the kidney. Spironolactone post-MI, diminished the progressive fibrosis (p<0.001) and inflammation (myofibroblasts (p<0.05); macrophages (p<0.01)) in both the heart and the kidney, despite persistently elevated SBP (182±19 mmHg). Despite the reduction in inflammation and fibrosis, spironolactone did not modify ejection fraction, proteinuria, or renal function when compared to untreated animals post MI. CONCLUSION This model of progressive cardiorenal dysfunction more closely replicates the clinical setting. Mineralocorticoid receptor blockade at a clinically relevant dose, blunted progression of cardiac and kidney fibrosis with reduction in cardiac and kidney inflammatory myofibroblast and macrophage infiltration. Further studies are underway to investigate the combined actions of angiotensin blockade with mineralocorticoid receptor blockade.
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Affiliation(s)
- C. J. Leader
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - G. T. Wilkins
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - R. J. Walker
- Department of Medicine, University of Otago, Dunedin, New Zealand
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4
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Shoemaker LN, Wilson LC, Lucas SJE, Machado L, Walker RJ, Cotter JD. Indomethacin markedly blunts cerebral perfusion and reactivity, with little cognitive consequence in healthy young and older adults. J Physiol 2020; 599:1097-1113. [DOI: 10.1113/jp280118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 11/05/2020] [Indexed: 12/11/2022] Open
Affiliation(s)
- L. N. Shoemaker
- School of Physical Education, Sport and Exercise Sciences University of Otago Dunedin New Zealand
| | - L. C. Wilson
- Department of Medicine Otago Medical School ‐ Dunedin Campus University of Otago Dunedin New Zealand
| | - S. J. E. Lucas
- Department of Physiology University of Otago Dunedin New Zealand
- School of Sport, Exercise and Rehabilitation Sciences College of Life and Environmental Sciences University of Birmingham Birmingham UK
- Centre for Human Brain Health University of Birmingham Birmingham UK
| | - L. Machado
- Department of Psychology University of Otago Dunedin New Zealand
| | - R. J. Walker
- Department of Medicine Otago Medical School ‐ Dunedin Campus University of Otago Dunedin New Zealand
| | - J. D. Cotter
- School of Physical Education, Sport and Exercise Sciences University of Otago Dunedin New Zealand
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5
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Hurcombe JA, Hartley P, Lay AC, Ni L, Bedford JJ, Leader JP, Singh S, Murphy A, Scudamore CL, Marquez E, Barrington AF, Pinto V, Marchetti M, Wong LF, Uney J, Saleem MA, Mathieson PW, Patel S, Walker RJ, Woodgett JR, Quaggin SE, Welsh GI, Coward RJM. Podocyte GSK3 is an evolutionarily conserved critical regulator of kidney function. Nat Commun 2019; 10:403. [PMID: 30679422 PMCID: PMC6345761 DOI: 10.1038/s41467-018-08235-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 12/21/2018] [Indexed: 01/18/2023] Open
Abstract
Albuminuria affects millions of people, and is an independent risk factor for kidney failure, cardiovascular morbidity and death. The key cell that prevents albuminuria is the terminally differentiated glomerular podocyte. Here we report the evolutionary importance of the enzyme Glycogen Synthase Kinase 3 (GSK3) for maintaining podocyte function in mice and the equivalent nephrocyte cell in Drosophila. Developmental deletion of both GSK3 isoforms (α and β) in murine podocytes causes late neonatal death associated with massive albuminuria and renal failure. Similarly, silencing GSK3 in nephrocytes is developmentally lethal for this cell. Mature genetic or pharmacological podocyte/nephrocyte GSK3 inhibition is also detrimental; producing albuminuric kidney disease in mice and nephrocyte depletion in Drosophila. Mechanistically, GSK3 loss causes differentiated podocytes to re-enter the cell cycle and undergo mitotic catastrophe, modulated via the Hippo pathway but independent of Wnt-β-catenin. This work clearly identifies GSK3 as a critical regulator of podocyte and hence kidney function.
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Affiliation(s)
- J A Hurcombe
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - P Hartley
- Bournemouth University, Bournemouth, BH12 5BB, UK
| | - A C Lay
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - L Ni
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - J J Bedford
- Dunedin School of Medicine, University of Otago, Dunedin, 9016, New Zealand
| | - J P Leader
- Dunedin School of Medicine, University of Otago, Dunedin, 9016, New Zealand
| | - S Singh
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - A Murphy
- Department of Pathology, Southern General Hospital, Glasgow, G51 4TF, UK
| | - C L Scudamore
- Mary Lyon Centre, MRC Harwell, Didcot, Oxford, OX11 0RD, UK
| | - E Marquez
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - A F Barrington
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - V Pinto
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - M Marchetti
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - L-F Wong
- Translational Health Sciences, University of Bristol, Bristol, BS2 8DZ, UK
| | - J Uney
- Translational Health Sciences, University of Bristol, Bristol, BS2 8DZ, UK
| | - M A Saleem
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - P W Mathieson
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
- The University of Hong Kong, Pokfulam, Hong Kong
| | - S Patel
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System & University of Toronto, Toronto, M5G 1X5, Canada
- Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - R J Walker
- Dunedin School of Medicine, University of Otago, Dunedin, 9016, New Zealand
| | - J R Woodgett
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System & University of Toronto, Toronto, M5G 1X5, Canada
| | - S E Quaggin
- Feinberg Cardiovascular Research Institute, Northwestern University Feinberg School of Medicine, Chicago, 60611, IL, USA
| | - G I Welsh
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK
| | - R J M Coward
- Bristol Renal, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK.
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6
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Campbell JA, Mendez CE, Garacci E, Walker RJ, Wagner N, Egede LE. The differential impact of adverse childhood experiences in the development of pre-diabetes in a longitudinal cohort of US adults. J Diabetes Complications 2018; 32:1018-1024. [PMID: 30236541 PMCID: PMC7553202 DOI: 10.1016/j.jdiacomp.2018.09.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/17/2018] [Accepted: 09/09/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND ACEs have a dose-response relationship with diabetes. The relationship between ACEs and pre-diabetes is not well known and may represent an effective area for prevention efforts. METHODS Data from 1054 participants from two waves of the longitudinal MIDUS study were used. Multivariate general linear regression models assessed the relationship between ACEs and biomarker outcomes. Correlation tests and mediation models investigated the relationship between ACE and pre-diabetes. RESULTS Individuals reporting ACEs were statistically significantly more likely to have higher BMI (1.13 (0.34-1.92)), higher waist circumference (2.74 (0.72-4.76)), elevated blood fasting insulin levels (2.36 (0.71-4.02)) and higher insulin resistance (HOMA-IR (0.57 (0.08-1.06)). BMI/waist circumference and insulin resistance did not maintain independent relationships with ACEs once HOMA-IR was included in the dichotomized ACE model (p = 0.05 and p = 0.06, respectively), suggesting the relationship between BMI and ACEs may be mediated by insulin resistance. CONCLUSIONS These results represent one of the first studies to examine the differential impact of ACEs on a diverse set of clinical pre-diabetes measures. Findings suggest sexual and physical abuse, and financial strain during childhood are important factors associated with higher risk for pre-diabetes, and should be considered during intervention development.
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Affiliation(s)
- J A Campbell
- Department of Medicine, Division of General Internal Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA; University of Wisconsin, Milwaukee, Joseph Zilber School of Public Health, 1240 N 10th Street, Milwaukee, WI 53205, USA
| | - C E Mendez
- Department of Medicine, Division of General Internal Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA
| | - E Garacci
- Department of Medicine, Division of General Internal Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA; Center for Advancing Population Science (CAPS), Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - R J Walker
- Department of Medicine, Division of General Internal Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA; Center for Advancing Population Science (CAPS), Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - N Wagner
- Department of Medicine, Division of General Internal Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA
| | - L E Egede
- Department of Medicine, Division of General Internal Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA; University of Wisconsin, Milwaukee, Joseph Zilber School of Public Health, 1240 N 10th Street, Milwaukee, WI 53205, USA.
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7
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Abstract
After the Moon's formation, Earth experienced a protracted bombardment by leftover planetesimals. The mass delivered during this stage of late accretion has been estimated to be approximately 0.5% of Earth's present mass, based on highly siderophile element concentrations in the Earth's mantle and the assumption that all highly siderophile elements delivered by impacts were retained in the mantle. However, late accretion may have involved mostly large (≥ 1,500 km in diameter)-and therefore differentiated-projectiles in which highly siderophile elements were sequestered primarily in metallic cores. Here we present smoothed-particle hydrodynamics impact simulations that show that substantial portions of a large planetesimal's core may descend to the Earth's core or escape accretion entirely. Both outcomes reduce the delivery of highly siderophile elements to the Earth's mantle and imply a late accretion mass that may be two to five times greater than previously thought. Further, we demonstrate that projectile material can be concentrated within localized domains of Earth's mantle, producing both positive and negative 182W isotopic anomalies of the order of 10 to 100 ppm. In this scenario, some isotopic anomalies observed in terrestrial rocks can be explained as products of collisions after Moon formation.
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Affiliation(s)
- S. Marchi
- Southwest Research Institute, Boulder, CO, USA
| | - R. M. Canup
- Southwest Research Institute, Boulder, CO, USA
| | - R. J. Walker
- Deptartment of Geology, University of MD, College Park, MD, USA
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8
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Zhou M, Berchem J, Walker RJ, El-Alaoui M, Deng X, Cazzola E, Lapenta G, Goldstein ML, Paterson WR, Pang Y, Ergun RE, Lavraud B, Liang H, Russell CT, Strangeway RJ, Zhao C, Giles BL, Pollock CJ, Lindqvist PA, Marklund G, Wilder FD, Khotyaintsev YV, Torbert RB, Burch JL. Coalescence of Macroscopic Flux Ropes at the Subsolar Magnetopause: Magnetospheric Multiscale Observations. Phys Rev Lett 2017; 119:055101. [PMID: 28949734 DOI: 10.1103/physrevlett.119.055101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Indexed: 06/07/2023]
Abstract
We report unambiguous in situ observation of the coalescence of macroscopic flux ropes by the magnetospheric multiscale (MMS) mission. Two coalescing flux ropes with sizes of ∼1 R_{E} were identified at the subsolar magnetopause by the occurrence of an asymmetric quadrupolar signature in the normal component of the magnetic field measured by the MMS spacecraft. An electron diffusion region (EDR) with a width of four local electron inertial lengths was embedded within the merging current sheet. The EDR was characterized by an intense parallel electric field, significant energy dissipation, and suprathermal electrons. Although the electrons were organized by a large guide field, the small observed electron pressure nongyrotropy may be sufficient to support a significant fraction of the parallel electric field within the EDR. Since the flux ropes are observed in the exhaust region, we suggest that secondary EDRs are formed further downstream of the primary reconnection line between the magnetosheath and magnetospheric fields.
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Affiliation(s)
- M Zhou
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - J Berchem
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - R J Walker
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - M El-Alaoui
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - X Deng
- Nanchang University, Nanchang 330031, People's Republic of China
| | - E Cazzola
- Centre for Plasma Astrophysics, Department of Mathematics, Katholieke Universiteit, Leuven 3001, Belgium
| | - G Lapenta
- Centre for Plasma Astrophysics, Department of Mathematics, Katholieke Universiteit, Leuven 3001, Belgium
| | - M L Goldstein
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
- Space Science Institute, Boulder 80301, Colorado, USA
| | - W R Paterson
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
| | - Y Pang
- Nanchang University, Nanchang 330031, People's Republic of China
| | - R E Ergun
- University of Colorado LASP, Boulder 80303, Colorado, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, UPS, CNES, Toulouse 31028, France
| | - H Liang
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - C T Russell
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - R J Strangeway
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - C Zhao
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - B L Giles
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
| | - C J Pollock
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
| | - P-A Lindqvist
- Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - G Marklund
- Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - F D Wilder
- University of Colorado LASP, Boulder 80303, Colorado, USA
| | | | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J L Burch
- Southwest Research Institute, San Antonio Texas 78238, USA
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9
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Stayner C, Poole CA, McGlashan SR, Pilanthananond M, Brauning R, Markie D, Lett B, Slobbe L, Chae A, Johnstone AC, Jensen CG, McEwan JC, Dittmer K, Parker K, Wiles A, Blackburne W, Leichter A, Leask M, Pinnapureddy A, Jennings M, Horsfield JA, Walker RJ, Eccles MR. An ovine hepatorenal fibrocystic model of a Meckel-like syndrome associated with dysmorphic primary cilia and TMEM67 mutations. Sci Rep 2017; 7:1601. [PMID: 28487520 PMCID: PMC5431643 DOI: 10.1038/s41598-017-01519-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 03/29/2017] [Indexed: 01/20/2023] Open
Abstract
Meckel syndrome (MKS) is an inherited autosomal recessive hepatorenal fibrocystic syndrome, caused by mutations in TMEM67, characterized by occipital encephalocoele, renal cysts, hepatic fibrosis, and polydactyly. Here we describe an ovine model of MKS, with kidney and liver abnormalities, without polydactyly or occipital encephalocoele. Homozygous missense p.(Ile681Asn; Ile687Ser) mutations identified in ovine TMEM67 were pathogenic in zebrafish phenotype rescue assays. Meckelin protein was expressed in affected and unaffected kidney epithelial cells by immunoblotting, and in primary cilia of lamb kidney cyst epithelial cells by immunofluorescence. In contrast to primary cilia of relatively consistent length and morphology in unaffected kidney cells, those of affected cyst-lining cells displayed a range of short and extremely long cilia, as well as abnormal morphologies, such as bulbous regions along the axoneme. Putative cilia fragments were also consistently located within the cyst luminal contents. The abnormal ciliary phenotype was further confirmed in cultured interstitial fibroblasts from affected kidneys. These primary cilia dysmorphologies and length control defects were significantly greater in affected cells compared to unaffected controls. In conclusion, we describe abnormalities involving primary cilia length and morphology in the first reported example of a large animal model of MKS, in which we have identified TMEM67 mutations.
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Affiliation(s)
- C Stayner
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - C A Poole
- Department of Medicine, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand.,150 Warren Street, Wanaka, 9305, New Zealand
| | - S R McGlashan
- Department of Anatomy and Medical Imaging, The University of Auckland 1142, Private Bag, 92019, Auckland, New Zealand
| | - M Pilanthananond
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - R Brauning
- AgResearch Invermay Agricultural Centre, Mosgiel, 9053, New Zealand
| | - D Markie
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - B Lett
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - L Slobbe
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - A Chae
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - A C Johnstone
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Tennant Drive, Palmerston North, 4472, New Zealand
| | - C G Jensen
- Department of Anatomy and Medical Imaging, The University of Auckland 1142, Private Bag, 92019, Auckland, New Zealand
| | - J C McEwan
- AgResearch Invermay Agricultural Centre, Mosgiel, 9053, New Zealand
| | - K Dittmer
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Tennant Drive, Palmerston North, 4472, New Zealand
| | - K Parker
- Department of Medicine, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - A Wiles
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - W Blackburne
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - A Leichter
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - M Leask
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - A Pinnapureddy
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - M Jennings
- Department of Medicine, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - J A Horsfield
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - R J Walker
- Department of Medicine, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - M R Eccles
- Department of Pathology, Dunedin School of Medicine, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
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10
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Camp P, Belonohy E, Carvalho IS, Knipe S, Lefebvre X, Medley SA, Olney R, Romanelli S, Shaw RCR, Smith R, Wakeling B, Walker RJ, Wilson D. ITER-Like Tokamak Exhaust Gases in JET Active Gas Handling System: Process Optioneering. Fusion Science and Technology 2017. [DOI: 10.1080/15361055.2017.1288457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- P. Camp
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - E. Belonohy
- Culham Centre for Fusion Energy , JET Exploitation Unit, Abingdon, Oxfordshire, OX14 3DB
| | - I. S. Carvalho
- Universidade de Lisboa , Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Lisboa P-1049-001, Portugal
| | - S. Knipe
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - X. Lefebvre
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - S. A. Medley
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - R. Olney
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - S. Romanelli
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - R. C. R. Shaw
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - R. Smith
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - B. Wakeling
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - R. J. Walker
- Culham Centre for Fusion Energy , Tritium Engineering & Science Group, Abingdon, Oxfordshire, OX14 3DB
| | - D. Wilson
- Culham Centre for Fusion Energy , Abingdon, Oxfordshire, OX14 3DB
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Parsons V, Walker RJ, Howorth PJN. Serum 5′ Nucleotidase and Alkaline Phosphatase Isoenzymes in Diagnosis, with Special Reference to Haemochromatosis. Ann Clin Biochem 2016. [DOI: 10.1177/000456327301000162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Serum 5′ nucleotidase (NTP) was determined on 91 sera by nickel inhibition and beta-glycerophosphate substrate competition; the latter method was found to be preferable. The isoenzyme pattern of serum alkaline phosphatase (ALP) in the same 91 sera was studied by polyacrylamide gel electrophoresis and was found more helpful in patient management than serum NTP. The serum ALP isoenzyme pattern was further studied in 50 patients with haemochromatosis. Nine out of 10 patients with clinical or radiological joint disease had a raised serum total ALP caused in half by the hepatic isoenzyme and half by the bone isoenzyme, without any clear-cut pattern. Four out of five patients with hepatoma had a raised serum total ALP due to the hepatic isoenzyme. The persistence of a high serum ALP in a patient treated actively for haemochromatosis may indicate malignant change in the liver.
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Affiliation(s)
| | - R. J. Walker
- Liver Unit, King's College Hospital, London, S.E.5
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Rizo H, Walker RJ, Carlson RW, Horan MF, Mukhopadhyay S, Manthos V, Francis D, Jackson MG. Preservation of Earth-forming events in the tungsten isotopic composition of modern flood basalts. Science 2016; 352:809-12. [DOI: 10.1126/science.aad8563] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 04/05/2016] [Indexed: 11/02/2022]
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Abstract
Understanding core formation in meteorite parent bodies is critical for constraining the fundamental processes of protoplanet accretion and differentiation within the solar protoplanetary disk. We report variations of 5 to 20 parts per million in (182)W, resulting from the decay of now-extinct (182)Hf, among five magmatic iron meteorite groups. These (182)W variations indicate that core formation occurred over an interval of ~1 million years and may have involved an early segregation of Fe-FeS and a later segregation of Fe melts. Despite this protracted interval of core formation, the iron meteorite parent bodies probably accreted concurrently ~0.1 to 0.3 million years after the formation of Ca-Al-rich inclusions. Variations in volatile contents among these bodies, therefore, did not result from accretion at different times from an incompletely condensed solar nebula but must reflect local processes within the nebula.
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Affiliation(s)
- T S Kruijer
- Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, DE-48149 Münster, Germany. ETH Zürich, Inst. of Geochemistry and Petrology, Clausiusstrasse 25, CH-8092 Zürich, Switzerland
| | - M Touboul
- Department of Geology, University of Maryland, College Park, MD 20742, USA
| | - M Fischer-Gödde
- Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, DE-48149 Münster, Germany
| | - K R Bermingham
- Department of Geology, University of Maryland, College Park, MD 20742, USA
| | - R J Walker
- Department of Geology, University of Maryland, College Park, MD 20742, USA
| | - T Kleine
- Institut für Planetologie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Strasse 10, DE-48149 Münster, Germany
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Affiliation(s)
- M L Wall
- Worcestershire Acute Hospitals NHS Trust, UK
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15
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Hoye NA, Baldi JC, Jardine DL, Wilkins GT, Wilson LC, Walker RJ, Dores H, Branco P, Silva Sousa H, Carvalho MS, Goncalves P, Almeida M, Andrade MJ, Gaspar MA, Pereira M, Barata JD, Mendes M, Ott C, Mahfoud F, Schmid A, Ditting T, Veelken R, Ewen S, Ukena C, Uder M, Bohm M, Schmieder RE, Schmieder RE, Mahfoud F, Schmid A, Ditting T, Veelken R, Uder M, Bohm M, Ott C, Vink EE, Verloop WL, Spiering W, Vonken EJ, Leiner T, Bots ML, Voskuil M, Blankestijn PJ. RENAL DENERVATION. Nephrol Dial Transplant 2014. [DOI: 10.1093/ndt/gfu111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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16
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Manning PJ, Sutherland WHF, Williams SM, Walker RJ, Berry EA, De Jong SA, Ryalls AR. The effect of lipoic acid and vitamin E therapies in individuals with the metabolic syndrome. Nutr Metab Cardiovasc Dis 2013; 23:543-549. [PMID: 22402059 DOI: 10.1016/j.numecd.2011.11.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [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: 08/11/2011] [Revised: 11/01/2011] [Accepted: 11/17/2011] [Indexed: 12/31/2022]
Abstract
The metabolic syndrome is associated with abnormal glucose and lipid metabolism, insulin resistance, increased oxidative stress and pro-inflammatory activity that increase the risk of type 2 diabetes and cardiovascular disease. The aim of this study was to investigate the effect of treatment with the antioxidant α-lipoic acid (ALA) with or without vitamin E supplementation, on markers of insulin resistance and systemic inflammation and plasma nonesterified fatty acid (NEFA) concentrations in individuals with the metabolic syndrome. In a randomized, double-blind, placebo-controlled trial, subjects with the metabolic syndrome received ALA (600 mg/day, n = 34), vitamin E (100 IU/day, n = 36), both ALA and vitamin E (n = 41), or matching placebo (n = 40) for 1 year. Fasting circulating concentrations of glucose and insulin were measure every 3 months and NEFA, markers of inflammation, adiponectin and vitamin E were measured at 6 monthly intervals. Plasma NEFA concentrations decreased [-10 (-18, 0)%] at a marginal level of significance (p = 0.05) in those who received ALA alone compared with placebo and decreased [-8 (-14, -1)% (95% CI)] significantly (P = 0.02) in participants who were randomised to ALA with and without vitamin E compared with those who did not receive ALA. Fasting glucose, insulin, homeostatic model assessment of insulin resistance, adiponectin, and markers of inflammation did not change significantly during the study. These data suggest that prolonged treatment with ALA may modestly reduce plasma NEFA concentrations but does not alter insulin or glucose levels in individuals with the metabolic syndrome.
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Affiliation(s)
- P J Manning
- Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
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Poole T, Stayner C, McGlashan SR, Parker K, Wiles A, Jennings M, Jensen CG, Johnstone AC, Walker RJ, Eccles MR. Primary cilia defects in the polycystic kidneys from an ovine model of Meckel Gruber syndrome. Cilia 2012. [PMCID: PMC3555837 DOI: 10.1186/2046-2530-1-s1-p97] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- T Poole
- University of Otago, New Zealand
| | | | | | - K Parker
- University of Otago, New Zealand
| | - A Wiles
- University of Otago, New Zealand
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Walker RJ, Kivelson MG. Energization of electrons at synchronous orbit by substorm-associated cross-magnetosphere electric fields. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja080i016p02074] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Singer HJ, Southwood DJ, Walker RJ, Kivelson MG. Alfven wave resonances in a realistic magnetospheric magnetic field geometry. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja086ia06p04589] [Citation(s) in RCA: 232] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Walker RJ, van Helden JH, Kirkbride J, McCormack EA, Bell MT, Weidmann D, Ritchie GAD. Rapid passage signals from a vibrationally excited target molecule: a pump and probe experiment with continuous wave quantum cascade lasers. Opt Lett 2011; 36:4725-4727. [PMID: 22179863 DOI: 10.1364/ol.36.004725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Two 5 µm continuous wave quantum cascade lasers are used to perform a counterpropagating pump and probe experiment on a low pressure sample of nitric oxide. The strong pump field excites a fundamental rovibrational transition and the weaker probe field is tuned to the corresponding rotationally resolved hot band transition. When both light fields are in resonance, rapid passage is observed in the hot band absorption lineshape arising from a minimally damped and velocity-selected sample of molecules in the v=1 state. The measured rapid passage signals are well described by a two-level model based on the optical Bloch equations.
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Affiliation(s)
- R J Walker
- Department of Chemistry, The Physical and Theoretical Chemistry Laboratory, The University of Oxford, Oxford, UK
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Lebedenko VN, Araújo HM, Barnes EJ, Bewick A, Cashmore R, Chepel V, Currie A, Davidge D, Dawson J, Durkin T, Edwards B, Ghag C, Horn M, Howard AS, Hughes AJ, Jones WG, Joshi M, Kalmus GE, Kovalenko AG, Lindote A, Liubarsky I, Lopes MI, Lüscher R, Lyons K, Majewski P, Murphy ASJ, Neves F, da Cunha JP, Preece R, Quenby JJ, Scovell PR, Silva C, Solovov VN, Smith NJT, Smith PF, Stekhanov VN, Sumner TJ, Thorne C, Walker RJ. Limits on the spin-dependent WIMP-nucleon cross sections from the first science run of the ZEPLIN-III experiment. Phys Rev Lett 2009; 103:151302. [PMID: 19905617 DOI: 10.1103/physrevlett.103.151302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 09/03/2009] [Indexed: 05/28/2023]
Abstract
We present new experimental constraints on the WIMP-nucleon spin-dependent elastic cross sections using data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter weakly interacting massive particles based at the Boulby mine. Analysis of approximately 450 kg x days fiducial exposure allow us to place a 90%-confidence upper limit on the pure WIMP-neutron cross section of sigma(n)=1.9x10(-2) pb at 55 GeV/c(2) WIMP mass. Recent calculations of the nuclear spin structure based on the Bonn charge-dependent nucleon-nucleon potential were used for the odd-neutron isotopes 129Xe and 131Xe. These indicate that the sensitivity of xenon targets to the spin-dependent WIMP-proton interaction could be much lower than implied by previous calculations, whereas the WIMP-neutron sensitivity is impaired only by a factor of approximately 2.
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Affiliation(s)
- V N Lebedenko
- Blackett Laboratory, Imperial College London, London, United Kingdom
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Hancock G, Horrocks SJ, Ritchie GAD, Helden JHV, Walker RJ. Time-Resolved Detection of the CF3 Photofragment Using Chirped QCL Radiation. J Phys Chem A 2008; 112:9751-7. [DOI: 10.1021/jp804849m] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. Hancock
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - S. J. Horrocks
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - G. A. D. Ritchie
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - J. H. van Helden
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - R. J. Walker
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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26
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Papaioannou S, Holden-Dye L, Walker RJ. The actions of Caenorhabditis elegans neuropeptide-like peptides (NLPs) on body wall muscle of Ascaris suum and pharyngeal muscle of C. elegans. Acta Biol Hung 2008; 59 Suppl:189-97. [PMID: 18652392 DOI: 10.1556/abiol.59.2008.suppl.28] [Citation(s) in RCA: 5] [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: 11/19/2022]
Abstract
The actions of six Neuropeptide-like Peptides (NLPs) were investigated on Ascaris suum dorsal body wall muscle and Caenorhabditis elegans pharyngeal muscle. The NLPs tested on A. suum muscle, viz, NLP-1A, NLP-2A and B, had no direct effect on the muscle but all reversibly reduced acetylcholine (ACh)-induced contractions of the muscle, NLP-2A being the most potent, with an IC50 value of 78 microM. NLP-2A also reversibly reduced ACh-induced depolarizations of A. suum muscle resting membrane potential. NLP-1A, NLP-2A, NLP-3C and NLP-10A all increased pharyngeal pumping in C. elegans, NLP-8A weakly inhibited pumping while NLP-2B was inactive. NLP-10A induced a concentration-dependent increase in pumping activity with a threshold of 10-100 nM. Since genes encoding NLPs (nlp genes) are expressed in C. elegans pharyngeal neurons it is likely these peptides play a role in feeding behaviour.
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Walker RJ. The 11th symposium on Invertebrate Neurobiology, Tihany, Hungary, 2007. Invert Neurosci 2008; 8:59-62. [PMID: 18180963 DOI: 10.1007/s10158-007-0065-z] [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] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- R J Walker
- School of Biological Sciences, University of Southampton, Southampton, SO16 7PX, UK.
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Weygand JM, Matthaeus WH, Dasso S, Kivelson MG, Walker RJ. Taylor scale and effective magnetic Reynolds number determination from plasma sheet and solar wind magnetic field fluctuations. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2007ja012486] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James M. Weygand
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - W. H. Matthaeus
- Bartol Research Institute and Department of Physics and Astronomy; University of Delaware; Delaware USA
| | - S. Dasso
- Instituto de Astronomía y Física del Espacio (IAFE) and Departmento de Física, Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; Argentina
| | - M. G. Kivelson
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
| | - R. J. Walker
- Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
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Joy SP, Kivelson MG, Walker RJ, Khurana KK, Russell CT, Paterson WR. Mirror mode structures in the Jovian magnetosheath. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006ja011985] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Weygand JM, Kivelson MG, Khurana KK, Schwarzl HK, Walker RJ, Balogh A, Kistler LM, Goldstein ML. Non-self-similar scaling of plasma sheet and solar wind probability distribution functions of magnetic field fluctuations. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2006ja011820] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Holden-Dye L, Walker RJ. Actions of glutamate and ivermectin on the pharyngeal muscle of Ascaridia galli: a comparative study with Caenorhabditis elegans. Int J Parasitol 2005; 36:395-402. [PMID: 16442540 DOI: 10.1016/j.ijpara.2005.11.006] [Citation(s) in RCA: 23] [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] [Received: 10/07/2005] [Revised: 11/14/2005] [Accepted: 11/15/2005] [Indexed: 11/16/2022]
Abstract
The actions of glutamate and ivermectin were examined in the pharynx of Ascaridia galli and the results compared with those on the pharynx of Caenorhabditis elegans. In both preparations glutamate elicits a depolarization and inhibition of pharyngeal pumping, but the response of the pharynx of A. galli was much less than for C. elegans. This may be either because the pharyngeal membrane potential of the former is closely linked to the equilibrium potential for chloride ions (E(Cl)) while that of C. elegans is independent of E(Cl), or that there is a lower density of glutamate receptors on the pharyngeal muscle of A. galli compared with C. elegans. The maximum depolarization to glutamate of the pharyngeal muscle was 4.5+/-0.8 mV in A. galli while it was >25 mV in C. elegans. Picrotoxin was a weak antagonist of the glutamate response in both species. Flufenamic acid, pentobarbitone and flurazepam had no significant effect on either preparation at concentrations up to 100 microM. Three glutamate receptor agonists, ibotenate, kainate and quisqualate were all more potent than glutamate on the A. galli pharyngeal muscle. In contrast, only ibotenate was more potent than glutamate in C. elegans pharynx, the other two agonists being approximately 20 times less potent. The potency of ivermectin differed markedly between the two species, being approximately three orders of magnitude less potent on the pharynx of A. galli compared with C. elegans. This study demonstrates clear differences between the properties of the pharyngeal muscle of the two species and shows that care must be taken when extrapolating data from free-living to parasitic species of nematode.
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Affiliation(s)
- L Holden-Dye
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO167PX, UK.
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Abstract
BACKGROUND A number of methods have been used to try to protect kidney function in patients undergoing surgery. These include the administration of dopamine, diuretics, calcium channel blockers, angiotensin converting enzyme inhibitors and hydration fluids. OBJECTIVES For this review, we selected randomized controlled trials, which employed different methods to protect renal function during the perioperative period. In examining these trials, we looked at outcomes such as renal failure and mortality, as well as changes in the renal function tests, including urine output, creatinine clearance, free water clearance, fractional excretion of sodium and renal plasma flow. SEARCH STRATEGY We searched the Cochrane Central register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2004), MEDLINE (1966 to 2004) and EMBASE (1988 to 2004) and hand searched six journals (British Journal of Anaesthesia; Anesthesia and Analgesia; Anesthesiology; Annals of Surgery; Journal of Thoracic and Cardiovascular Surgery and Journal of Vascular Surgery). SELECTION CRITERIA We selected all randomized controlled trials in adult population undergoing surgery where a treatment measure was used for the purpose of renal protection in the perioperative period. DATA COLLECTION AND ANALYSIS We selected 37 studies for inclusion in this review. As well as analysis of the data from all the studies, we also performed subgroup analysis for type of interventions, types of surgical procedures and those with pre-existing renal dysfunction. We undertook sensitivity analysis on studies with high methodological quality. MAIN RESULTS The review included data from 37 studies, comprising a total of 1227 patients. Of these, 658 received some form of treatment and 569 acted as controls. The interventions were mostly employing different pharmaceutical agents such as dopamine, diuretics, calcium channel blockers. ACE inhibitors or selected hydration fluids. The results indicated that certain interventions showed some benefits, but all the results suffered from significant heterogeneity. Hence we can draw no conclusions about the effectiveness of these interventions in protecting the kidneys during surgery. AUTHORS' CONCLUSIONS There is no reliable evidence from available literature to suggest that interventions during surgery can protect the kidneys from damage. However, there is a need for more studies of high methodological quality. One particular area for further studies may be on patients with pre-existing renal dysfunction undergoing surgery.
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Affiliation(s)
- M Zacharias
- Anaesthesia & Intensive Care, Dunedin Hospital, Great King Street, Dunedin, Otago, New Zealand.
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Abstract
Historically, peptidergic substances (in the form of neurosecretions) were linked to moulting in nematodes. More recently, there has been a renewal of interest in nematode neurobiology, initially triggered by studies demonstrating the localization of peptide immunoreactivities to the nervous system. Here, David Brownlee, Ian Fairweather, Lindy Holden-Dye and Robert Walker will review progress on the isolation of nematode neuropeptides and efforts to unravel their physiological actions and inactivation mechanisms. Future avenues for research are suggested and the potential exploitation of peptidergic pathways in future therapeutic strategies highlighted.
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Affiliation(s)
- D J Brownlee
- School of Biology and Biochemistry, The Queen's University of Belfast, Belfast, UK
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Franks CJ, Walker RJ, Holden-Dye L. A structure-activity study of the neuropeptide PF1, SDPNFLRFamide, using the dorsal body wall muscle of the chicken nematode, Ascaridia galli. Acta Biol Hung 2005; 55:343-51. [PMID: 15270251 DOI: 10.1556/abiol.55.2004.1-4.40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The action of a range of N terminally modified peptides structurally related to the nematode peptide PF1, SDPNFLRFamide, has been investigated using a dorsal muscle strip preparation from the chicken nematode, Ascaridia galli. Acetylcholine contracts this muscle preparation in a concentration-dependent manner when applied in the range 1-100 microM with an EC50 value of 9 microM. These contractions are reduced in the presence of PF1 and its analogues, with a threshold effect of PF1 of around 1 nM and an IC50 value of 470 nM against 10 microM acetylcholine. All the PF1 analogues tested were less potent than PF1 in reducing the acetylcholine contractions, indicating the importance of the N terminal amino acids in the action of PF1 in this preparation.
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Affiliation(s)
- C J Franks
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, UK
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Walker RJ, Sutherland WHF, De Jong SA. Effect of changing from a cellulose acetate to a polysulphone dialysis membrane on protein oxidation and inflammation markers. Clin Nephrol 2004; 61:198-206. [PMID: 15077871 DOI: 10.5414/cnp61198] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In vitro, synthetic dialysis membranes induce less activation of blood components to produce pro-inflammatory cytokines and reactive oxygen species compared with cellulose acetate membranes. However, the long-term effect of switching from a cellulose-based dialysis membrane to a synthetic membrane on protein oxidation and systemic inflammation in hemodialysis patients is not well defined. METHODS Nineteen patients receiving hemodialysis were followed prospectively after changing from a low-flux cellulose acetate membrane to a low-flux polysulphone membrane for 11-17 months (n = 15) and then returning to the cellulose acetate membrane for 1 month (n = 13). Plasma markers of protein oxidation, cell activation and systemic inflammation and concentrations of soluble cell adhesion molecules were measured at baseline and at the end of each intervention period. RESULTS Plasma levels of protein thiols (18%), IL-6 (34%), VCAM-1 (33%), ICAM-1 (21%) and beta2-microglobulin (21%) increased significantly and dityrosine fluorescence (-36%), protein lipofuscin-like fluorophores (-18%) and TNF-alpha (-20%) decreased significantly in the patients after they switched to the polysulphone membrane. After reverting to the cellulose acetate membrane for 1 month, plasma levels of protein thiols and IL-6 returned to baseline while levels of other variables were not significantly different from values at the end of the polysulphone dialysis period. There was substantial intra-individual variation between 2 baseline measurements of plasma cytokines. CONCLUSIONS Switching from a cellulose acetate membrane to a low-flux polysulphone dialysis membrane for a year or more may decrease the level of protein oxidation suggesting a decrease in oxidant stress and greater biocompatibility of the polysulphone membrane. The effect of this change in dialysis membrane on systemic inflammation is uncertain due to increases in some but not other inflammation-sensitive molecules.
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Affiliation(s)
- R J Walker
- Department of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.
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White AR, Curtis SA, Walker RJ. Evidence for a possible role for nitric oxide in the modulation of heart activity in Achatina fulica and Helix aspersa. Comp Biochem Physiol C Toxicol Pharmacol 2004; 137:95-108. [PMID: 15050921 DOI: 10.1016/j.cca.2003.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Revised: 11/24/2003] [Accepted: 11/25/2003] [Indexed: 10/26/2022]
Abstract
The effects of nitric oxide (NO) donors, S-nitroso-N-acetylpenicillamine, S-nitroso-l-glutathione, sodium nitroprusside and sodium nitrite were investigated on the activity of the isolated hearts of Achatina fulica and Helix aspersa. NO donors inhibited heart activity in a concentration-dependent manner. The only exception was sodium nitroprusside, which excited H. aspersa heart. The inhibitory effects of these NO donors were reduced by the NO scavenger, methylene blue, the guanylyl cyclase inhibitor, 1H-(1,2,4) Oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), and potentiated by 8-Br-cGMP and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Acetylcholine also inhibited the heart activity, and this inhibition was reduced by methylene blue and ODQ. Positive NADPH-diaphorase staining was located in the outer pericardial layer of the heart of A. fulica. The present results provide evidence that NO may modulate the activity of gastropod hearts, and this modulation may modify the inhibitory action of acetylcholine on heart activity.
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Affiliation(s)
- A R White
- School of Biological Sciences, Biomedical Sciences Building, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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Pivovarov AS, Walker RJ. Effects of SEPYLRFamide on acetylcholine-induced currents of Helix aspersa neurones: role of ryanodine receptors. Invert Neurosci 2003; 4:17-24. [PMID: 12491070 DOI: 10.1007/pl00022365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
The possible participation of ryanodine receptors in the modulatory effects of the endogenous Helix heptapeptide, SEPYLRFamide, on the acetylcholine-induced currents (ACh-currents) of Helix aspersa neurones was studied using the two-electrode voltage clamp technique. SEPYLRFamide (bath application) caused a reduction of the ACh-currents of D1, D2, F1, F2, F76 and F77 neurones. Ryanodine (10 microM; bath application), which modifies ryanodine-controlled Ca(2+) channels, potentiated the inhibitory effect of SEPYLRFamide on the ACh-current. An antagonist of cyclic adenosine diphosphate ribose (cADPR) and ryanodine receptors, ruthenium red (1 mM; intracellular injection), reduced the inhibitory effects of SEPYLRFamide on the ACh-current. Ryanodine (10 microM) did not change the inhibitory effect of SEPYLRFamide on the ACh-current after intracellular injection of ruthenium red. An agonist of ryanodine receptors, caffeine (5 mM; bath application), reduced the ACh-current. Ryanodine (10 microM) did not change the reduction of ACh-currents induced by the first application of caffeine but decreased the reduction of ACh-currents induced by subsequent applications of caffeine. It is proposed that ryanodine receptors are involved in the inhibitory modulatory effects of SEPYLRFamide on somatic cholinergic receptors of Helix aspersa neurones.
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Affiliation(s)
- A S Pivovarov
- Department of Physiology and Pharmacology, University of Southampton, Bassett Crescent East, Southampton S016 7PX, UK
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Willson J, Amliwala K, Harder A, Holden-Dye L, Walker RJ. The effect of the anthelmintic emodepside at the neuromuscular junction of the parasitic nematode Ascaris suum. Parasitology 2003; 126:79-86. [PMID: 12613766 DOI: 10.1017/s0031182002002639] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Here we report on the action of the novel cyclo-depsipeptide anthelmintic, emodepside, on the body wall muscle of the parasitic nematode, Ascaris suum. Emodepside caused (i) muscle relaxation, (ii) inhibition of muscle contraction elicited by either acetylcholine (ACh), or the neuropeptide, AF2 (KHEYLRFamide) and (iii) a rapid relaxation of muscle tonically contracted by ACh. The inhibitory action of emodepside on the response to ACh was not observed in a denervated muscle strip, indicating that it may exert this action through the nerve cord, and not directly on the muscle. Electrophysiological recordings showed emodepside elicited a Ca(++)-dependent hyperpolarization of muscle cells. Furthermore, the response to emodepside was dependent on extracellular K+, similar to the action of the inhibitory neuropeptides PF1 and PF2 (SDPNFLRFamide and SADPNFLRFamide). Thus emodepside may act at the neuromuscular junction to stimulate release of an inhibitory neurotransmitter or neuromodulator, with a similar action to the PF1/PF2 neuropeptides.
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Affiliation(s)
- J Willson
- Southampton Neuroscience Group, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK
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Kurth WS, Gurnett DA, Hospodarsky GB, Farrell WM, Roux A, Dougherty MK, Joy SP, Kivelson MG, Walker RJ, Crary FJ, Alexander CJ. The dusk flank of Jupiter's magnetosphere. Nature 2002; 415:991-4. [PMID: 11875558 DOI: 10.1038/415991a] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Limited single-spacecraft observations of Jupiter's magnetopause have been used to infer that the boundary moves inward or outward in response to variations in the dynamic pressure of the solar wind. At Earth, multiple-spacecraft observations have been implemented to understand the physics of how this motion occurs, because they can provide a snapshot of a transient event in progress. Here we present a set of nearly simultaneous two-point measurements of the jovian magnetopause at a time when the jovian magnetopause was in a state of transition from a relatively larger to a relatively smaller size in response to an increase in solar-wind pressure. The response of Jupiter's magnetopause is very similar to that of the Earth, confirming that the understanding built on studies of the Earth's magnetosphere is valid. The data also reveal evidence for a well-developed boundary layer just inside the magnetopause.
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Affiliation(s)
- W S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA.
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Rogers CM, Franks CJ, Walker RJ, Burke JF, Holden-Dye L. Regulation of the pharynx of Caenorhabditis elegans by 5-HT, octopamine, and FMRFamide-like neuropeptides. J Neurobiol 2001; 49:235-44. [PMID: 11745661 DOI: 10.1002/neu.1078] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
More than fifty FMRFamide-like neuropeptides have been identified in nematodes. We addressed the role of a subset of these in the control of nematode feeding by electrophysiological recording of the activity of C. elegans pharynx. AF1 (KNEFIRFamide), AF2 (KHEYLRFamide), AF8 (KSAYMRFamide), and GAKFIRFamide (encoded by the C. elegans genes flp-8, flp-14, flp-6, and flp-5, respectively) increased pharyngeal action potential frequency, in a manner similar to 5-HT. In contrast, SDPNFLRFamide, SADPNFLRFamide, SAEPFGTMRFamide, KPSVRFamide, APEASPFIRFamide, and AQTVRFamide (encoded by the C. elegans genes flp-1; flp-1; flp-3; flp-9; flp-13, and flp-16, respectively) inhibited the pharynx in a manner similar to octopamine. Only three of the neuropeptides had potent effects at low nanomolar concentrations, consistent with a physiological role in pharyngeal regulation. Therefore, we assessed whether these three peptides mediated their actions either directly on the pharynx or indirectly via the neural circuit controlling its activity by comparing actions between wild-type and mutants with deficits in synaptic signaling. Our data support the conclusion that AF1 and SAEPFGTMRFamide regulate the activity of the pharynx indirectly, whereas APEASPFIRFamide exerts its action directly. These results are in agreement with the expression pattern for the genes encoding the neuropeptides (Kim and Li, 1999) as both flp-8 and flp-3 are expressed in extrapharyngeal neurons, whereas flp-13 is expressed in I5, a neuron with synaptic output to the pharyngeal muscle. These results provide the first, direct, functional information on the action of neuropeptides in C. elegans. Furthermore, we provide evidence for a putative inhibitory peptidergic synapse, which is likely to have a role in the control of feeding.
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Affiliation(s)
- C M Rogers
- Centre for Neuroscience, School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton S016 7PX, United Kingdom
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Abstract
Although cytomegalovirus (CMV) infection is common in renal transplant recipients, urinary tract involvement has been rare. Only six cases of symptomatic ureteritis have been reported in renal transplant recipients and all within the last five years. We describe an additional four cases of CMV ureteritis. The presentation of CMV ureteritis is obstructive nephropathy often in the absence of systemic illness. Presentation may also mimic allograft rejection with minimal obstructive symptoms. We hypothesize that CMV ureteritis is an emerging complication of CMV disease, possibly due to changes in transplant practice.
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Affiliation(s)
- M C Thomas
- Renal Unit, The Queen Elizabeth Hospital, Adelaide, Australia.
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Pedder SM, Muneoka Y, Walker RJ. Structure-activity and possible mode of action of S-Iamide neuropeptides on identified central neurons of Helix aspersa. Regul Pept 2001; 101:131-40. [PMID: 11495688 DOI: 10.1016/s0167-0115(01)00279-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Intracellular recordings were made from identified neurons from the suboesophageal ganglia of Helix aspersa. The inhibitory action of nine S-Iamide peptides was investigated. Structure-activity studies suggest that all act through a common receptor, which normally requires FVRIamide at the C terminal, with a preferred length of seven amino acids. Substitution at the N-terminal with alanine (A), threonine (T), proline (P) or leucine (L) results in little change in potency, suggesting the N-terminal requirements are relatively flexible. Ion substitution experiments suggest that potassium is the main ion involved in the inhibitory response to S-Iamide application. Studies using a range of compounds, which modify second messenger systems, would suggest that S-Iamide peptides may interact with adenylate cyclase. No evidence was found for an interaction with either guanylate cyclase or nitric oxide synthase.
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Affiliation(s)
- S M Pedder
- Department of Physiology and Pharmacology, School of Biological Sciences, University of Southampton, Bassett Crescent East, SO16 7PX, Southampton, UK
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Affiliation(s)
- M J Williams
- Department of Medical and Surgical Sciences, Dunedin School of Medicine, University of Otago, New Zealand.
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Williams MJ, Sutherland WH, McCormick MP, Yeoman D, de Jong SA, Walker RJ. Normal endothelial function after meals rich in olive or safflower oil previously used for deep frying. Nutr Metab Cardiovasc Dis 2001; 11:147-152. [PMID: 11590989] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
BACKGROUND AND AIM Polyunsaturated fats are more susceptible to oxidation during heating than monounsaturated fats but their effects on endothelial function when heated are unknown. The aim of this study was to compare the effect of meals rich in heat-modified safflower and olive oils on postprandial flow-mediated endothelium-dependent dilation (EDD) in healthy men. METHODS AND RESULTS Flow-mediated EDD and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were investigated in 14 subjects before and 4 hours after meals rich in olive oil and safflower oil used hourly for deep-frying for 8 hours in a double-blind crossover study design. There were high levels of lipid oxidation products (peroxides and carbonyls) in both heated oils. Plasma triglycerides were markedly increased at 4 hours after heated olive oil (1.26 +/- 0.43 vs 2.06 +/- 0.97 mmol/L) and heated safflower oil (1.44 +/- 0.63 vs 1.99 +/- 0.88 mmol/L). There was no change in EDD between fasting and postprandial studies and the response during the postprandial period was not significantly (p = 0.51) different between the meals (heated olive oil: 4.9 +/- 2.2% vs 4.9 +/- 2.5%; heated safflower oil: 5.1 +/- 3.1% vs 5.6 +/- 3.4%). CONCLUSIONS Meals rich in olive and safflower oils previously used for deep frying and containing high levels of lipid oxidation products increase postprandial serum triglycerides without affecting endothelial function. These findings suggest that relatively short-term use of these vegetable oils for frying may not adversely affect postprandial endothelial function when foods containing the heat-modified oils are consumed.
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Affiliation(s)
- M J Williams
- Department of Medicine, Dunedin School of Medicine, University of Otago, 201 Great King Street, Dunedin, New Zealand
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Williams MJ, Sutherland WH, McCormick MP, de Jong SA, McDonald JR, Walker RJ. Vitamin C improves endothelial dysfunction in renal allograft recipients. Nephrol Dial Transplant 2001; 16:1251-5. [PMID: 11390728 DOI: 10.1093/ndt/16.6.1251] [Citation(s) in RCA: 37] [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] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Endothelial function is impaired in renal allograft recipients but the effects of antioxidant vitamin therapy on endothelial function in such patients is unknown. METHODS Thirteen renal allograft recipients were randomized to vitamin C or placebo in a double blind cross-over study design. Flow-mediated endothelium-dependent dilation and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were assessed before and 2 h after oral administration of 2 g vitamin C or placebo. RESULTS Plasma vitamin C levels increased from 33.5+/-17.0 micromol/l to 98.8+/-60.2 micromol/l after treatment (P=0.0001). Endothelium-dependent dilation improved (from 1.6+/-2.6 to 4.5+/-2.5%) after vitamin C administration but was unchanged after placebo (1.9+/-1.5 to 1.8+/-2.5%; P=0.003 for vitamin C vs placebo). There was no significant change in endothelium-independent dilation in response to vitamin C. Vitamin C was also associated with a significant increase in the lag time in dilute serum oxidation (P=0.001). CONCLUSIONS Vitamin C acutely improves flow-mediated, endothelium-dependent dilation and increases the resistance of lipoproteins in dilute serum to oxidation in renal transplant recipients.
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Affiliation(s)
- M J Williams
- Department of Medicine, University of Otago, PO Box 913, Dunedin, New Zealand
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Pemberton DJ, Franks CJ, Walker RJ, Holden-Dye L. Characterization of glutamate-gated chloride channels in the pharynx of wild-type and mutant Caenorhabditis elegans delineates the role of the subunit GluCl-alpha2 in the function of the native receptor. Mol Pharmacol 2001; 59:1037-43. [PMID: 11306685 DOI: 10.1124/mol.59.5.1037] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glutamate-gated chloride (GluCl) channels are the site of action of the anthelmintic ivermectin. Previously, the Xenopus laevis oocyte expression system has been used to characterize GluCl channels cloned from Caenorhabditis elegans. However, information on the native, pharmacologically relevant receptors is lacking. Here, we have used a quantitative pharmacological approach and intracellular recording techniques of C. elegans pharynx to characterize them. The glutamate response was a rapidly desensitizing, reversible, chloride-dependent depolarization (EC(50) = 166 microM), only weakly antagonized by picrotoxin. The order of potency of agonists was ibotenate > L-glutamate > kainate = quisqualate. Ivermectin potently and irreversibly depolarized the muscle (EC(50) = 2.7 nM). No further depolarization was seen with coapplication of maximal glutamate during the maximal ivermectin response, indicating that ivermectin depolarizes the muscle by the same ionic mechanism as glutamate (i.e., chloride). The potency of ivermectin on the pharynx was greater than at any of the GluCl subunits expressed in X. laevis oocytes. This effect of ivermectin was abolished in the mutant avr-15, which lacks a functional GluCl-alpha2 subunit. However, a chloride-dependent, nondesensitizing response to glutamate persisted. Therefore, the GluCl-alpha2 subunit confers ivermectin sensitivity and a high-affinity desensitizing glutamate response on the native pharyngeal GluCl receptor.
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Affiliation(s)
- D J Pemberton
- Centre for Neuroscience, University of Southampton, Bassett Crescent East, Southampton UK
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Waite JH, Gladstone GR, Lewis WS, Goldstein R, McComas DJ, Riley P, Walker RJ, Robertson P, Desai S, Clarke JT, Young DT. An auroral flare at Jupiter. Nature 2001; 410:787-9. [PMID: 11298440 DOI: 10.1038/35071018] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Jupiter's aurora is the most powerful in the Solar System. It is powered largely by energy extracted from planetary rotation, although there seems also to be a contribution from the solar wind. This contrasts with Earth's aurora, which is generated through the interaction of the solar wind with the magnetosphere. The major features of Jupiter's aurora (based on far-ultraviolet, near-infrared and visible-wavelength observations) include a main oval that generally corotates with the planet and a region of patchy, diffuse emission inside the oval on Jupiter's dusk side. Here we report the discovery of a rapidly evolving, very bright and localized emission poleward of the northern main oval, in a region connected magnetically to Jupiter's outer magnetosphere. The intensity of the emission increased by a factor of 30 within 70 s, and then decreased on a similar timescale, all captured during a single four-minute exposure. This type of flaring emission has not previously been reported for Jupiter (similar, but smaller, transient events have been observed at Earth), and it may be related directly to changes in the solar wind.
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Affiliation(s)
- J H Waite
- Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Chia KK, Cracknell AP, Walker RJ. General expansions for a geometrical plane wave parametrization scheme for the Fermi surfaces of BCC, FCC, and HCP metals. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0305-4608/4/8/008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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