Publications
348 results found
Seemungal T, Donaldson GC, Paul EA, et al., 1996, Time series analysis of FEV<inf>1</inf> in patients with exacerbations of COPD, Thorax, Vol: 51, ISSN: 0040-6376
Deterioration in lung function is found when patients present with exacerbations of COPD but little is known of changes before and after onset of symptoms. Between October 1995 and March 1996, a group of 25 COPD patients from East London (22M, 3F; mean(SD) age 66.1(9.1) yrs, FEV1 1120 (440) ml, FVC 2460(640) ml, PaO2 8.79(1.23) kPa) recorded on diary cards, daily morning FEV1 and FVC (Micro Medical Ltd spirometers), peak flow rate and changes in respiratory symptoms. Eighteen patients had 30 exacerbations (E); range 1-4/patient. Diagnosis was made by one physician using criteria based on Anthonisen et al (Ann Intern Med. 1987:106; 196-204). For each E the regression coefficient of FEV1 or FVC on time prior to E was calculated. Significance of these from zero was tested by Wilcoxon signed-rank test. Three different intervals were examined. For days 14 to 8 prior to E, FEV1 and FVC did not fall significantly, median slope -25 ml/d (P=0.308) and -0.5 ml/d (P=0.422) respectively, and were taken as baseline. Over days 7 to 1 prior to E, FEV1 fell moderately, median slope -4 ml/d (P=0.042) but not FVC, median slope 1.5 ml/d (P=0.989). On days 1 to 0, both fell markedly, median slope FEV1 -50 ml/min/d (P=0.004) and FVC -130 ml/d (p<0.001). Recovery, defined as the time at which the 3 day moving average of each parameter exceeded or was nearest baseline, took for FEV1 9.3 (7.1) days and for FVC 9.4(7.1) days. The increased airflow obstruction prior to the onset of E suggests the involvement of viral and other environmental factors in the pathogenesis of exacerbations.
Donaldson GC, Scarborough M, Mridha K, et al., 1996, Erratum: Effect of posture on body temperature of young men in cold air (European Journal of Applied Physiology (1996) 73 (326-331)), European Journal of Applied Physiology and Occupational Physiology, Vol: 74, ISSN: 0301-5548
Donaldson GC, Scarborough M, Mridha K, et al., 1996, Effect of posture on body temperature of young men in cold air, Eur J Appl Physiol Occup Physiol, Vol: 73, Pages: 326-331, ISSN: 0301-5548
We studied eight young adult men to see whether a supine posture caused a fall in body core temperature in the cold, as it does in thermoneutral conditions. In air at 31 degrees C (thermoneutral), a supine posture for 3 h reduced mean aural, gastric, oesophageal and rectal temperatures by 0.2-0.4 degree C, compared to upright and increased femoral artery blood flow from 278 (SEM 42)ml.min-1 whilst upright to 437 (SEM 42) ml.min-1 whilst supine. In cold air (8 degrees C) the supine posture failed to reduce these temperatures [corrected] significantly, or to increase femoral blood flow: it reduced heart rate, and increased arterial systolic and pulse pressures adjusted to carotid sinus level, less than in thermoneutral conditions. However, the behaviour of core temperature at the four sites was significantly nonuniform between the two postures in the cold, mainly because the supine posture tended to reduce rectal temperature. It may have done so by reducing heat production in the muscles of the pelvis, since it reduced overall metabolic rate from 105 (SEM 8) to 87 (SEM 4) W.m-2 in the cold. In other respects the results indicated that posture ceased to have an important effect on body core temperatures during cold stress.
GLASS NL, DONALDSON GC, 1995, DEVELOPMENT OF PRIMER SETS DESIGNED FOR USE WITH THE PCR TO AMPLIFY CONSERVED GENES FROM FILAMENTOUS ASCOMYCETES, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Vol: 61, Pages: 1323-1330, ISSN: 0099-2240
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- Citations: 3199
DONALDSON GC, BALL LA, AXELROOD PE, et al., 1995, PRIMER SETS DEVELOPED TO AMPLIFY CONSERVED GENES FROM FILAMENTOUS ASCOMYCETES ARE USEFUL IN DIFFERENTIATING FUSARIUM SPECIES ASSOCIATED WITH CONIFERS, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Vol: 61, Pages: 1331-1340, ISSN: 0099-2240
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- Citations: 57
Davies BN, Donaldson GC, Joels N, 1995, Do the competition rules of synchronized swimming encourage undesirable levels of hypoxia?, Br J Sports Med, Vol: 29, Pages: 16-19, ISSN: 0306-3674
Recent anecdotal reports that some synchronized swimmers have become dizzy or disorientated towards the end of their performance, and in the worst cases fainted underwater, have caused concern. However, the rules of synchronized swimming encourage slow performance of compulsory figures, and an analysis of the competition placings and duration of underwater sequences showed that the highest rankings were gained by slowly performed compulsory figures and free programmes containing a long underwater sequence. The combination of breath-holding and the vigorous exercise involved suggests that some of the symptoms complained of by the swimmers might be due to hypoxia. We therefore studied the alveolar gas tensions in nine members of the Great Britain National Squad immediately following the performance of set figures and the initial underwater sequence of their free routine in a swimming-bath. All were cyanosed after the underwater sequences of the free routine and reported being mildly confused. The mean(s.d.) alveolar PO2 at this stage was 5.07(1.1) KPa, while three girls had an alveolar PO2 below 4 KPa, the lowest being 3.67 KPa. These gas tensions suggest that potentially dangerous levels of hypoxia may develop during competitive synchronized swimming and that prolonged underwent sequences should not be encouraged.
Keatinge WR, Donaldson GC, 1995, Cardiovascular mortality in winter, Arctic Med Res, Vol: 54 Suppl 2, Pages: 16-18, ISSN: 0782-226X
Ischaemic heart disease is the biggest single cause of excess mortality in winter, accounting for approximately half of all the excess deaths. Most of these deaths take place hours or a day or two after exposure to cold suggesting that some result from thrombosis starting during or shortly after cold exposure, although some can result from immediate reflex effects of cold, and some can occur in association with respiratory deaths which are delayed many days after cold weather. Changes in blood composition observed in the cold that may explain the rapid thrombotic deaths include increased red cell count, plasma cholesterol, and plasma fibrinogen, which are all thrombogenic. The protective protein C does not increase significantly. British data suggests that cold housing particularly affects respiratory mortality in winter, and outdoor cold exposures mortality from arterial thrombosis. A Europe-wide survey is now being run as part of the EC- funded project "Eurowinter" to assess such factors.
MARCHANT B, DONALDSON G, MRIDHA K, et al., 1994, MECHANISMS OF COLD INTOLERANCE IN PATIENTS WITH ANGINA, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 23, Pages: 630-636, ISSN: 0735-1097
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- Citations: 36
Neild PJ, Syndercombe-Court D, Keatinge WR, et al., 1994, Cold-induced increases in erythrocyte count, plasma cholesterol and plasma fibrinogen of elderly people without a comparable rise in protein C or factor X, Clin Sci (Lond), Vol: 86, Pages: 43-48, ISSN: 0143-5221
1. Six elderly (66-71 years) and six young (20-23 years) subjects (half of each group women) were cooled for 2 h in moving air at 18 degrees C to investigate possible causes of increased mortality from arterial thrombosis among elderly people in cold weather. Compared with thermoneutral control experiments, skin temperature (trunk) fell from 35.5 to 29.5 degrees C, with little change in core temperature. 2. Erythrocyte count rose in the cold from 4.29 to 4.69 x 10(12)/l, without a change in mean corpuscular volume, indicating a 14% or 438 ml decline in plasma volume; increased excretion of water, Na+ and K+ accounted for loss of only 179 ml of extracellular water. 3. Plasma cholesterol and fibrinogen concentrations rose in the elderly subjects from 4.90 mmol/l and 2.97 g/l (control) to 5.45 mmol/l and 3.39 g/l in the cold, and in the young subjects from 3.33 mmol/l and 1.84 g/l (control) to 3.77 mmol/l and 2.07 g/l in the cold. Increases were significant for the elderly subjects, the young subjects and the group as a whole, except for cholesterol in the young subjects, and all were close to those expected from the fall in plasma volume. 4. Plasma levels of Protein C and factor X did not increase significantly in the cold in the elderly subjects, young subjects, or the group as a whole. 5. The results suggest that loss of plasma fluid in the cold concentrates major risk factors for arterial thrombosis, while small molecules, including protective Protein C, redistribute to interstitial fluid.
Mattock M, Syndercombe-Court D, Keatinge WR, et al., 1993, Increases in plasma cholesterol in elderly and young adults during exposure to cold without increase in Factors VII or X, ISSN: 0022-3751
WHELAN LJ, SCARBOROUGH M, DONALDSON GC, et al., 1993, USE OF TURBULENT AIR TO STABILIZE SKIN TEMPERATURE DURING INVESTIGATION OF EFFECTS OF POSTURAL CHANGE ON THERMOREGULATION IN MAN, Publisher: CAMBRIDGE UNIV PRESS, Pages: P11-P11, ISSN: 0022-3751
DONALDSON GC, MRIDHA KA, WHELAN L, et al., 1993, EFFECTS OF POSTURE ON CORE TEMPERATURE DURING COLD STRESS IN MAN, Publisher: CAMBRIDGE UNIV PRESS, Pages: P79-P79, ISSN: 0022-3751
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SYNDERCOMBECOURT D, KEATINGE WR, DONALDSON GC, et al., 1993, INCREASED PLASMA-FIBRINOGEN IN YOUNG AND ELDERLY HUMAN ADULTS DURING BRIEF EXPOSURE TO COLD, Publisher: CAMBRIDGE UNIV PRESS, Pages: P81-P81, ISSN: 0022-3751
Donaldson GC, 1992, The chaotic behaviour of resting human respiration, Respir Physiol, Vol: 88, Pages: 313-321, ISSN: 0034-5687
The study of non-linear mathematics has led to the concept of an attractor that can confine to within certain boundaries the path traced out in multidimensional space when a variable is plotted against itself delayed by various lag times. The type of attractor present can be determined by monitoring the exponential rate (called a Lyapunov exponent) at which almost identical values within a time series become dissimilar. Lyapunov exponents estimated from data collected during the normal resting breathing of eight adults were all positive, end-tidal PCO2 had the lowest Lyapunov exponent (0.06 +/- 0.01 bits/s; Mean +/- SE), breath and expiratory duration had the highest exponents (0.23 bits/s). The results indicate that resting respiration is chaotic. This chaotic behaviour may allow fast and flexible responses to sudden changes, allow if necessary complete readjustment of the control parameters, and may be involved in the phase locking of respiration to external stimuli.
Donaldson GC, Skehan JD, Keatinge WR, 1990, Use of early portion of expiration for single-breath estimation of cardiac output, P(v, CO<inf>2</inf>) and P(a, CO<inf>2</inf>), ISSN: 0022-3751
Newstead CG, Donaldson GC, Sneyd JR, 1990, Potassium as a respiratory signal in humans, J Appl Physiol, Vol: 69, Pages: 1799-1803, ISSN: 8750-7587
Six renal transplant recipients underwent a series of incremental exercise experiments. Minute ventilation (VE), carbon dioxide production rate (VCO2), and arterial blood chemistry were measured at rest and while subjects exercised on a stationary bicycle. Four of the subjects performed a similar experiment while exercising on a static rowing machine. Within each subject, arterial potassium concentration ([K+]a) was linearly related to VCO2 and VE during exercise. The slope of the relationship between [K+]a and VCO2 was similar in the cycling and rowing experiments. This implies that the absorption of potassium by resting muscle does not significantly limit the arterial hyperkalemia seen during exercise. When VE, VCO2, and [K+]a were measured 1 and 5 min after the end of cycling there was no correlation, whereas VE continued to be closely correlated with VCO2. The relationship demonstrated between change in [K+]a and VCO2 in these experiments is compatible with change of [K+]a acting as a respiratory signal during exercise but not during recovery from exercise in humans.
Hearn VM, Donaldson GC, Healy MJ, 1985, A method to determine significant levels of immunoglobulin G to Aspergillus fumigatus antigens in an ELISA system and a comparison with counterimmunoelectrophoresis and double diffusion techniques, J Immunoassay, Vol: 6, Pages: 137-158, ISSN: 0197-1522
A method is described which assesses results obtained from an ELISA system for the determination of human serum levels of IgG class antibodies to Aspergillus fumigatus. The method is used to discriminate positive from negative samples, and significant antibody activity may be reported to the clinician, relative to a reference positive control serum monitored simultaneously under the same test conditions. Antibody content is expressed as the absorbance of a certain dilution of serum. Duplicate samples were analysed at a single serum dilution and their absorbtion values obtained from a semi-automated ELISA microplate reader. These were entered into a computer programmed to convert the data into units on a logarithmic scale. In parallel experiments, ELISA results were compared with those obtained by the techniques of counterimmunoelectrophoresis and double diffusion which measure precipitating antibody of all classes. A relatively good degree of correlation between tests was found only among sera with a high level of antibody.
Hearn VM, Donaldson GC, Healy MJ, et al., 1985, A method to determine significant levels of immunoglobulin G to Aspergillus fumigatus antigens in an ELISA system and a comparison with counterimmunoelectrophoresis and double diffusion techniques, J Immunoassay, Vol: 6, Pages: 165-187, ISSN: 0197-1522
A method is described which assesses results obtained from an ELISA system for the determination of human serum levels of IgG class antibodies to Aspergillus fumigatus. The method is used to discriminate positive from negative samples, and significant antibody activity may be reported to the clinician, relative to a reference positive control serum monitored simultaneously under the same test conditions. Antibody content is expressed as the absorbance of a certain dilution of serum. Duplicate samples were analysed at a single serum dilution and their absorbtion values obtained from a semi-automated ELISA microplate reader. These were entered into a computer programmed to convert the data into units on a logarithmic scale. In parallel experiments, ELISA results were compared with those obtained by the techniques of counterimmunoelectrophoresis and double diffusion which measure precipitating antibody of all classes. A relatively good degree of correlation between tests was found only among sera with a high level of antibody.
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