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Hulton AT, Lahart I, Williams KL, Godfrey R, Charlesworth S, Wilson M, Pedlar C, Whyte G. Energy expenditure in the Race Across America (RAAM). Int J Sports Med 2010; 31:463-7. [PMID: 20455193 DOI: 10.1055/s-0030-1251992] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Energy Expenditure was measured with doubly labelled water technique during heavy sustained exercise with an official finishing team in the Race Across America. Energy Intake was also calculated to produce an energy balance for the race. A team of 4 cyclists (Mean +/-SD age: 37+4 yr; body height: 182+8 cm; body mass: 80.8+6.6 kg) completed the race in a relay fashion. The team completed the race in 6 days 10 h and 51 min. Total mean energy expenditure was found to be 43,401 kcals (181,711 kJ) with a mean daily energy expenditure of 6,420 kcals (26,879 kJ). Total mean energy intake from all food and drink consumed was calculated at 29,506 kcals (123,536 kJ) with a mean daily energy intake of 4 918 kcals (20,591 kJ). This resulted in a total mean energy deficit of 13,878 kcals (58,104 kJ) with a mean daily energy deficit of 1,503 kcals (6,293 kJ). The high energy expenditure highlights the need for correct and practical dietary strategies and challenges nutritionists to devise high energy diets that not only contain the correct macronutrient balance, but are also palatable to the cyclists, thus encouraging a high energy intake.
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Theberge AB, Whyte G, Huck WTS. Generation of Picoliter Droplets with Defined Contents and Concentration Gradients from the Separation of Chemical Mixtures. Anal Chem 2010; 82:3449-53. [DOI: 10.1021/ac1005316] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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53
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Shim JU, Olguin LF, Whyte G, Scott D, Babtie A, Abell C, Huck WTS, Hollfelder F. Simultaneous determination of gene expression and enzymatic activity in individual bacterial cells in microdroplet compartments. J Am Chem Soc 2009; 131:15251-6. [PMID: 19799429 DOI: 10.1021/ja904823z] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A microfluidic device capable of storing picoliter droplets containing single bacteria at constant volumes has been fabricated in PDMS. Once captured in droplets that remain static in the device, bacteria express both a red fluorescent protein (mRFP1) and the enzyme, alkaline phosphatase (AP), from a biscistronic construct. By measuring the fluorescence intensity of both the mRFP1 inside the cells and a fluorescent product formed as a result of the enzymatic activity outside the cells, gene expression and enzymatic activity can be simultaneously and continuously monitored. By collecting data from many individual cells, the distribution of activities in a cell is quantified and the difference in activity between two AP mutants is measured.
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Wilson M, O'Hanlon R, Prasad S, Oxborough D, Godfrey R, Alpendurada F, Smith G, Wong J, Basavarajaiah S, Sharma S, Nevill A, Gaze D, George K, Whyte G. Biological markers of cardiac damage are not related to measures of cardiac systolic and diastolic function using cardiovascular magnetic resonance and echocardiography after an acute bout of prolonged endurance exercise. Br J Sports Med 2009; 45:780-4. [PMID: 19854761 DOI: 10.1136/bjsm.2009.064089] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVES Seventeen male participants (mean (SD) (range): age 33.5 (6.5) years (46-26 years), body mass 80 (9.2) kg (100-63 kg), height 1.81 (0.06) m (1.93- 1.70 m)) ran a marathon to investigate the relationship between systolic function (using cardiac magnetic resonance (CMR)) and diastolic function (using echocardiography) against biomarkers of cardiac damage. METHODS Echocardiographic and cardiac troponin I (cTnI)/N-terminal pro-B-type natriuretic peptide (NTproBNP) data were collected 24 h premarathon, immediately postmarathon and 6 h postmarathon. CMR data were collected 24 h premarathon and at 6 h postmarathon. RESULTS Body mass was significantly reduced postmarathon (80 (9.2) vs 78.8 (8.6) kg; p<0.001). There was a significant E/A reduction postmarathon (1.11 (0.34) vs 1.72 (0.44); p<0.05) that remained depressed 6 h postmarathon (1.49 (0.43); p<0.05). CMR demonstrated left ventricular end-diastolic and end-systolic volumes were reduced postmarathon, with a preserved stroke volume. Left ventricular ejection fraction 6 h postmarathon significantly increased (64.4% (4.2%) vs 67.4% (5%); p<0.05). There were significant elevations in cTnI (0.00 vs 0.04 (0.03) μg/l; p<0.05) and NTproBNP (37.4 (24.15) ng/l vs 59.34 (43.3) ng/l; p<0.05) immediately postmarathon. Eight runners had cTnI elevations immediately postmarathon above acute myocardial infarction cutoff levels (≥0.03 μg/l). No correlations between cTnI/NTproBNP and measures of diastolic function (E, A, E/A, isovolumic relaxation time, E deceleration time and E/E') or measures of systolic function (stroke volume or ejection fraction) were observed immediately postmarathon or 6 h postmarathon. CONCLUSIONS Biomarkers of cardiac damage after prolonged exercise are not associated with either systolic or diastolic functional measures.
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de Noronha SV, Sharma S, Papadakis M, Desai S, Whyte G, Sheppard MN. Aetiology of sudden cardiac death in athletes in the United Kingdom: a pathological study. Heart 2009; 95:1409-14. [PMID: 19443476 DOI: 10.1136/hrt.2009.168369] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Fidalgo L, Whyte G, Ruotolo B, Benesch J, Stengel F, Abell C, Robinson C, Huck W. Coupling Microdroplet Microreactors with Mass Spectrometry: Reading the Contents of Single Droplets Online. Angew Chem Int Ed Engl 2009; 48:3665-8. [DOI: 10.1002/anie.200806103] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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57
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Fidalgo L, Whyte G, Ruotolo B, Benesch J, Stengel F, Abell C, Robinson C, Huck W. Coupling Microdroplet Microreactors with Mass Spectrometry: Reading the Contents of Single Droplets Online. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200806103] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Oxborough D, Batterham AM, Shave R, Artis N, Birch KM, Whyte G, Ainslie PN, George KP. Interpretation of two-dimensional and tissue Doppler-derived strain ( ) and strain rate data: is there a need to normalize for individual variability in left ventricular morphology? EUROPEAN JOURNAL OF ECHOCARDIOGRAPHY 2009; 10:677-82. [DOI: 10.1093/ejechocard/jep037] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Courtois F, Olguin LF, Whyte G, Theberge AB, Huck WTS, Hollfelder F, Abell C. Controlling the Retention of Small Molecules in Emulsion Microdroplets for Use in Cell-Based Assays. Anal Chem 2009; 81:3008-16. [DOI: 10.1021/ac802658n] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Huebner A, Bratton D, Whyte G, Yang M, Demello AJ, Abell C, Hollfelder F. Static microdroplet arrays: a microfluidic device for droplet trapping, incubation and release for enzymatic and cell-based assays. LAB ON A CHIP 2009; 9:692-8. [PMID: 19224019 DOI: 10.1039/b813709a] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We describe the design, fabrication and use of a single-layered poly(dimethylsiloxane) microfluidic structure for the entrapment and release of microdroplets in an array format controlled entirely by liquid flow. Aqueous picoliter droplets are trapped en masse and optically monitored for extended periods of time. Such an array-based approach is used to characterize droplet shrinkage, aggregation of encapsulated E. coli cells and enzymatic reactions. We also demonstrate that trapped droplets may be recovered from the microfluidic array for further processing.
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Whyte G, Whyte G, Stephens N, Senior R, George K, Shave R, Wilson M, Sharma S. Treat the patient not the blood test: the implications of an increase in cardiac troponin after prolonged endurance exercise. CASE REPORTS 2009; 2009:bcr08.2008.0756. [DOI: 10.1136/bcr.08.2008.0756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Theberge AB, Whyte G, Frenzel M, Fidalgo LM, Wootton RCR, Huck WTS. Suzuki–Miyaura coupling reactions in aqueous microdroplets with catalytically active fluorous interfaces. Chem Commun (Camb) 2009:6225-7. [DOI: 10.1039/b911594c] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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63
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Euser TG, Whyte G, Scharrer M, Chen JSY, Abdolvand A, Nold J, Kaminski CF, Russell PSJ. Dynamic control of higher-order modes in hollow-core photonic crystal fibers. OPTICS EXPRESS 2008; 16:17972-17981. [PMID: 18958077 DOI: 10.1364/oe.16.017972] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present a versatile method for selective mode coupling into higher-order modes of photonic crystal fibers, using holograms electronically generated by a spatial light modulator. The method enables non-mechanical and completely repeatable changes in the coupling conditions. We have excited higher order modes up to LP(31) in hollow-core photonic crystal fibers. The reproducibility of the coupling allows direct comparison of the losses of different guided modes in both hollow-core bandgap and kagome-lattice photonic crystal fibers. Our results are also relevant to applications in which the intensity distribution of the light inside the fiber is important, such as particle- or atom-guidance.
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Laird BJA, Whyte G, Laird JH, Soutar RL, Welsh J, Fallon MT. Letter to editor: an observational study of red cell transfusion in specialist palliative care. Palliat Med 2008; 22:874-5. [PMID: 18718992 DOI: 10.1177/0269216308094521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Courtois F, Olguin LF, Whyte G, Bratton D, Huck WTS, Abell C, Hollfelder F. An integrated device for monitoring time-dependent in vitro expression from single genes in picolitre droplets. Chembiochem 2008; 9:439-46. [PMID: 18232037 DOI: 10.1002/cbic.200700536] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microdroplets have great potential for high-throughput biochemical screening. We report the design of an integrated microfluidic device for droplet formation, incubation and screening. Picolitre water-in-oil droplets can be stored in a reservoir that contains approximately 10(6) droplets. In this reservoir droplets are stable for at least 6 h, which gives an extended timescale for biochemical experiments. We demonstrate the utility of the system by following the in vitro expression of green fluorescent protein. The high efficiency allows protein expression from a single molecule of DNA template, creating "monoclonal droplets" in which genotype and phenotype are combined in one emulsion compartment.
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Huebner A, Olguin LF, Bratton D, Whyte G, Huck WTS, de Mello AJ, Edel JB, Abell C, Hollfelder F. Development of quantitative cell-based enzyme assays in microdroplets. Anal Chem 2008; 80:3890-6. [PMID: 18399662 DOI: 10.1021/ac800338z] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the development of an enzyme assay inside picoliter microdroplets. The enzyme alkaline phosphatase is expressed in Escherichia coli cells and presented in the periplasm. Droplets act as discrete reactors which retain and localize any reaction product. The catalytic turnover of the substrate is measured in individual droplets by monitoring the fluorescence at several time points within the device and exhibits kinetic behavior similar to that observed in bulk solution. Studies on wild type and a mutant enzyme successfully demonstrated the feasibility of using microfluidic droplets to provide time-resolved kinetic measurements.
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Whyte G, Sheppard M, George K, Shave R, Wilson M, Prasad S, O'Hanlon R, Sharma S. Post-mortem evidence of idiopathic left ventricular hypertrophy and idiopathic interstitial myocardial fibrosis: is exercise the cause? Br J Sports Med 2008; 42:304-5. [PMID: 17720799 DOI: 10.1136/bjsm.2007.038158] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A growing body of evidence reporting altered cardiac function and myocardial damage after arduous exercise, together with the increased prevalence of arrhythmias observed in highly trained athletes, suggests that repetitive bouts of prolonged, arduous exercise may be deleterious to long-term cardiac health. We report the case of an experienced, highly trained marathon runner who died suddenly while running. On post-mortem examination, left ventricle hypertrophy and idiopathic interstitial myocardial fibrosis was found. We believe that life-long, repetitive bouts of arduous physical activity resulted in fibrous replacement of the myocardium, causing a pathological substrate for the propagation of fatal arrhythmias.
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Gibson G, Carberry DM, Whyte G, Leach J, Courtial J, Jackson JC, Robert D, Miles M, Padgett M. Holographic assembly workstation for optical manipulation. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1464-4258/10/4/044009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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69
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Fidalgo L, Whyte G, Bratton D, Kaminski C, Abell C, Huck W. From Microdroplets to Microfluidics: Selective Emulsion Separation in Microfluidic Devices. Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200704903] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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70
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Fidalgo L, Whyte G, Bratton D, Kaminski C, Abell C, Huck W. From Microdroplets to Microfluidics: Selective Emulsion Separation in Microfluidic Devices. Angew Chem Int Ed Engl 2008; 47:2042-5. [DOI: 10.1002/anie.200704903] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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71
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Whyte G, George K, Shave R, Middleton N, Nevill A. Training Induced Changes in Maximum Heart Rate. Int J Sports Med 2008; 29:129-33. [DOI: 10.1055/s-2007-965783] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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72
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Andrus C, Penava D, Chittle A, McDonald C, Scott S, Taylor S, Whyte G. Dispensing Plan B in London, Ontario, 1 year after Schedule II status. Contraception 2007. [DOI: 10.1016/j.contraception.2007.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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73
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Dawson EA, Shave R, Whyte G, Ball D, Selmer C, Jans Ø, Secher NH, George KP. Preload maintenance and the left ventricular response to prolonged exercise in men. Exp Physiol 2007; 92:383-90. [PMID: 17158180 DOI: 10.1113/expphysiol.2006.035089] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined whether left ventricular function was reduced during 3 h of semi-recumbent ergometer cycling at 70% of maximal oxygen uptake while preload to the heart was maintained via saline infusion. Indices of left ventricular systolic function (end-systolic blood pressure-volume relationship, SBP/ESV) and diastolic filling (ratio of early to late peak filling velocities into the left ventricle, E:A) were calculated during recovery and compared with baseline resting data. During exercise in seven healthy, trained male subjects, an arterial catheter allowed continuous assessment of arterial pressure, stroke volume (SV), cardiac output ( ) and an index of contractility (dP/dt(max)). A venous catheter assessed that central venous pressure (CVP) was maintained throughout rest, exercise and 10 min into recovery. Both systolic blood pressure and heart rate (HR) increased with the onset of exercise (from 132 +/- 5 to 185 +/- 19 mmHg and from 66 +/- 9 to 135 +/- 23 beats min(-1); increases from rest to the end of the first 5 min of exercise in SBP and HR, respectively) but systolic blood pressure did not change from 30 to 180 min of exercise ( approximately 150 mmHg), while heart rate only increased by 8 +/- 9 beats min(-1) (means +/- s.d.; P > 0.05). The attenuated increase in HR compared with other studies suggests that the maintained CVP ( approximately 5 mmHg) helped to prevent cardiovascular drift in this protocol. Stroke volume, and dP/dt(max) were all increased with the onset of exercise (from 85 +/- 8 to 120 +/- 18 ml, from 5.4 +/- 1.3 to 16.5 +/- 3.3 l min(-1) and from 14.4 +/- 4 to 28 +/- 8 mmHg s(-1); values from rest to the end of the first 5 min of exercise for SV, and dP/dt(max), respectively) and were maintained during exercise. There was no difference in the SBP/ESV ratio from pre- to postexercise. Conversely, E:A was reduced from 2.0 +/- 0.4 to 1.6 +/- 0.5 postexercise (P < 0.05), returning to normal values at 24 h postexercise. This change in diastolic filling could not be fully explained (r(2) = 0.39) by an increased heart rate and, with CVP unchanged, it is likely to represent some depression of intrinsic relaxation properties of left ventricular myocytes. Three hours of semi-supine cycling resulted in no evidence of a depression in left ventricular systolic function, while left ventricular diastolic function declined postexercise.
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Whyte G, Stephens N, Senior R, George K, Shave R, Wilson M, Sharma S. Treat the patient not the blood test: the implications of an increase in cardiac troponin after prolonged endurance exercise. Br J Sports Med 2007; 41:613-5; discussion 615. [PMID: 17261549 PMCID: PMC2465398 DOI: 10.1136/bjsm.2006.033720] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Collapse after prolonged endurance exercise is common and usually benign. This case study reports a triathlete who suffered a vaso-vagal associated collapsed after exercise. Misdiagnosis of myocardial injury in the presence of elevated cardiac troponins and ECG anomalies led to inappropriate management and highlights the difficulty in treating the collapsed athlete following arduous exercise.
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Whyte G. Improved safety of clinical blood transfusion in four provinces of China 1997-2005. DEVELOPMENTS IN BIOLOGICALS 2007; 127:197-204. [PMID: 17486893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This paper outlines the activities of the Blood Component of the World Bank Health IX Program in China over the period 1997-2005. There has been a large and sustainable improvement in the safety of the systems that provide blood for transfusion in four provinces of China. This success is only one of the many great improvements that have occurred across the whole country.
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