Changes In Peak Flow Research Articles

Changes in peak flow with decreased forestry practices: Analysis using watershed runoff data

The prevalence of forestry practices such as thinning and pruning have gradually decreased since the 1980s. Researchers have noted an increased flood risk with decreased forestry practices for coniferous plantations in Japan on the basis of infiltration and overland flow measurements at a plot scale (typically several square meters). However, no studies have examined changes in peak flow with decreased forestry practices at a watershed scale (typically several tens or hundreds of square kilometers) even though flood disasters generally occur at this scale in Japan. We examined changes in frequency distributions of daily precipitation (P) and runoff (Q) during the period 1979–2007 at the Terauchi watershed, where forestry practices are known to have decreased. For this purpose, we divided P and Q data into 14 and 15 classes according to the magnitude, respectively, and examined changes in the frequency for each class during the period. We observed no significant increasing trend for any P or Q class. Even when taking into account the effect of interannual variations in precipitation on the frequency for each Q class, there was no significant increasing trend in the frequencies except for two Q classes with moderate Q values. These results suggest that the increase in flood risk due to decreased forestry practices might be less than expected.

Coronary Microvascular Function in Early Chronic Kidney Disease

coronary microvascular dysfunction may underlie the high cardiovascular risk associated with chronic kidney disease (CKD), but the effects of CKD on coronary microvasculature function remain uncertain. we assessed myocardial blood flow changes in mild-to-moderate CKD and analyzed the association between creatinine clearance (CrCl) and peak myocardial blood flow and coronary flow reserve (CFR) measured as the ratio of stress to rest perfusion at baseline and at 1 year in 435 nondiabetic individuals who underwent quantitative rest and pharmacological stress positron emission tomography imaging. At baseline, CFR was significantly associated with CrCl (β per 10 mL/min increase, 0.07; P=0.001). Factors such as age and blood pressure accounted for this association, and it was not significant in adjusted analyses (β=-0.02, P=0.53). Peak flow was not associated with CrCl in either crude or adjusted analyses (β per 10 mL/min=-0.02 mL/min per g, P=0.29). Although change in peak flow at 1 year was similar in patients with and without CKD, CrCl was a strong and independent predictor of a higher rate of change in CFR, with a loss of 0.11 CFR units/y (95% confidence interval, 0.01 to 0.20) for each 10 mL/min drop in CrCl (P=0.03). these findings demonstrate that mild-to-moderate CKD is not independently associated with a reduction in peak myocardial flow or CFR and suggests that microvascular changes are unlikely to explain the high cardiovascular mortality in mild to moderate CKD. Loss of CFR, however, may accelerate in mild to moderate CKD. Further studies are needed to determine whether these changes lead to more significant reductions that may reduce peak flows and CFR and contribute to cardiovascular risk in more severe CKD.

Scenario-neutral approach to climate change impact studies: Application to flood risk

This paper presents a novel framework for undertaking climate change impact studies, which can be used for testing the robustness of precautionary climate change allowances used in engineering design. It is illustrated with respect to fluvial flood risk in the UK. The methodology departs from conventional scenario-led impact studies because it is based on sensitivity analyses of catchment responses to a plausible range of climate changes (rather than the time-varying outcome of individual scenarios), making it scenario-neutral. The method involves separating the climate change projections (the hazard) from the catchment responsiveness (the vulnerability) expressed as changes in peak flows. By combining current understanding of likelihood of the climate change hazard with knowledge of the sensitivity of a given catchment, it is possible to evaluate the fraction of climate model projections that would not be accommodated by specified safety margins. This enables rapid appraisal of existing or new precautionary allowances for a set of climate change projections, but also for any new set of climate change projections for example arising from a new generation of climate models as soon as they are available, or when focusing on a different planning time horizon, without the need for undertaking a new climate change impact analysis with the new scenarios. The approach is demonstrated via an assessment of the UK Government’s 20% allowance for climate change applied in two contrasting catchments. In these exemplars, the allowance defends against the majority of sampled climate projections for the 2080s from the IPCC-AR4 GCM and UKCP09 RCM runs but it is still possible to identify a sub-set of regional scenarios that would exceed the 20% threshold.

Climate change impacts on streamflow extremes and summertime stream temperature and their possible consequences for freshwater salmon habitat in Washington State

This study evaluates the sensitivity of Washington State’s freshwater habitat of Pacific Salmon (Oncorhynchus spp.) to climate change. Our analysis focuses on summertime stream temperatures, seasonal low flows, and changes in peak and base flows because these physical factors are likely to be key pressure points for many of Washington’s salmon populations. Weekly summertime water temperatures and extreme daily high and low streamflows are evaluated under multimodel composites for A1B and B1 greenhouse gas emissions scenarios. Simulations predict rising water temperatures will thermally stress salmon throughout Washington’s watersheds, becoming increasingly severe later in the twenty-first century. Streamflow simulations predict that basins strongly influenced by transient runoff (a mix of direct runoff from cool-season rainfall and springtime snowmelt) are most sensitive to climate change. By the 2080s, hydrologic simulations predict a complete loss of Washington’s snowmelt dominant basins, and only about ten transient basins remaining in the north Cascades. Historically transient runoff watersheds will shift towards rainfall dominant behavior, undergoing more severe summer low flow periods and more frequent days with intense winter flooding. While cool-season stream temperature changes and impacts on salmon are not assessed in this study, it is possible that climate-induced warming in winter and spring will benefit parts of the freshwater life-cycle of some salmon populations enough to increase their reproductive success (or overall fitness). However, the combined effects of warming summertime stream temperatures and altered streamflows will likely reduce the reproductive success for many Washington salmon populations, with impacts varying for different life history-types and watershed-types. Diminishing streamflows and higher stream temperatures in summer will be stressful for stream-type salmon populations that have freshwater rearing periods in summer. Increased winter flooding in transient runoff watersheds will likely reduce the egg-to-fry survival rates for ocean-type and stream-type salmon.

Land-cover impacts on streamflow: a change-detection modelling approach that incorporates parameter uncertainty

The effect of land-use or land-cover change on stream runoff dynamics is not fully understood. In many parts of the world, forest management is the major land-cover change agent. While the paired catchment approach has been the primary methodology used to quantify such effects, it is only possible for small headwater catchments where there is uniformity in precipitation inputs and catchment characteristics between the treatment and control catchments. This paper presents a model-based change-detection approach that includes model and parameter uncertainty as an alternative to the traditional paired-catchment method for larger catchments. We use the HBV model and data from the HJ Andrews Experimental Forest in Oregon, USA, to develop and test the approach on two small (<1 km2) headwater catchments (a 100% clear-cut and a control) and then apply the technique to the larger 62 km2 Lookout catchment. Three different approaches are used to detect changes in stream peak flows using: (a) calibration for a period before (or after) change and simulation of runoff that would have been observed without land-cover changes (reconstruction of runoff series); (b) comparison of calibrated parameter values for periods before and after a land-cover change; and (c) comparison of runoff predicted with parameter sets calibrated for periods before and after a land-cover change. Our proof-of-concept change detection modelling showed that peak flows increased in the clear-cut headwater catchment, relative to the headwater control catchment, and several parameter values in the model changed after the clear-cutting. Some minor changes were also detected in the control, illustrating the problem of false detections. For the larger Lookout catchment, moderately increased peak flows were detected. Monte Carlo techniques used to quantify parameter uncertainty and compute confidence intervals in model results and parameter ranges showed rather wide distributions of model simulations. While this makes change detection more difficult, it also demonstrated the need to explicitly consider parameter uncertainty in the modelling approach to obtain reliable results. Citation Seibert, J. & McDonnell, J. J. (2010) Land-cover impacts on streamflow: a change-detection modelling approach that incorporates parameter uncertainty. Hydrol. Sci. J. 55(3), 316–332.

β2-Receptor Polymorphisms in Patients Receiving Salmeterol with or without Fluticasone Propionate

Retrospective pharmacogenetic studies have questioned whether patients with asthma who are arginine homozygous at the beta(2-)adrenergic receptor (position 16) should use long-acting beta-agonists. To examine whether the response to salmeterol alone or in combination with an inhaled corticosteroid is influenced by beta- receptor polymorphisms. Subjects using only as-needed albuterol were screened and completed two sequential open-label run-in periods (8 wk on as-needed albuterol; 8 wk on as-needed ipratropium). Five hundred forty-four subjects were randomized by Arg16Gly genotype to salmeterol alone or with fluticasone propionate for 16 weeks. Change from baseline in morning peak expiratory flow was the primary endpoint. Lung function responses were sustained over treatment and no statistically significant changes from baseline between genotypes within treatments were observed. Overall mean changes in morning peak flow for salmeterol with fluticasone propionate were 32.6 L/min (Arg/Arg vs. Gly/Gly, 95% confidence interval [CI], -6.3, 22.1), 25.9 L/min (Arg/Arg vs. Arg/Gly, 95% CI, -7.1, 21.3), and 24.9 L/min (Arg/Gly vs. Gly/Gly, 95% CI, -13.0, 14.6), and for salmeterol alone were 19.4 L/min (Arg/Arg vs. Gly/Gly, 95% CI, -1.7, 21.4), 24.6 L/min (Arg/Arg vs. Arg/Gly, 95% CI, -13.0, 10.6), and 12.4 L/min (Arg/Gly vs. Gly/Gly, 95% CI, -0.2, 22.3) for Arg/Arg, Arg/Gly, and Gly/Gly genotypes, respectively. Other measures of asthma control showed similar responses. The results showed no evidence of a pharmacogenetic effect of beta-receptor variation on salmeterol response. Clinical trial registered with www.clinicaltrials.gov (NCT 00102882).

Physiologic affects of altitude on recreational climbers

Objectives Previous analyses of physiologic parameter changes during ascent to altitude have incorporated small numbers of well-trained climbers. The effects of altitude illness are more likely to occur and may come to medical attention more frequently in unacclimatized recreational individuals. We sought to evaluate acute changes in physiologic parameters during ascent to high altitude (14 100 ft) in recreational climbers. Methods We performed a prospective naturalistic study of 221 recreational climbers at Mount Shasta (peak altitude of 14 162 ft). Baseline vital signs were recorded at 3500 ft (blood pressure, heart rate, respiratory rate, pulse oximetry, and peak flow). Subsequent measurements were obtained at 6700 ft, 10 400 ft, and at the summit. Mean vital signs and the amount they changed with altitude were estimated using mixed linear models. Results One hundred twenty-five climbers (56.6%) reached the summit. Heart rate increased and pulse oximetry decreased with ascent (mean, 71.9, 79, 97, and 102.4 beats/min and 96.9%, 93.9%, 88.8%, and 80.8%, respectively), with estimates at each altitude differing statistically at P < .0001. Mean systolic and diastolic blood pressures varied significantly by altitude (not measured at summit), but the changes were not monotonic. Peak flow progressively declined with ascent, but the difference between 6700 and 10 400 was not statistically significant. Respiratory rate did not change significantly. Conclusions Acute compensation for altitude-induced hypoxia involves numerous physiologic changes; this is supported by our data that demonstrate significant changes in blood pressure and stepwise changes in pulse oximetry, peak flow, and heart rate. Consideration of these changes can be incorporated in future studies of the affect of altitude on recreational climbers.

Randomized trial of the effect of drug presentation on asthma outcomes: The American Lung Association Asthma Clinical Research Centers

Information that enhances expectations about drug effectiveness improves the response to placebos for pain. Although asthma symptoms often improve with placebo, it is not known whether the response to placebo or active treatment can be augmented by increasing expectation of benefit. The study objective was to determine whether response to placebo or a leukotriene antagonist (montelukast) can be augmented by messages that increase expectation of benefit. A randomized 20-center controlled trial enrolled 601 asthmatic patients with poor symptom control who were assigned to one of 5 study groups. Participants were randomly assigned to one of 4 treatment groups in a factorial design (ie, placebo with enhanced messages, placebo with neutral messages, montelukast with enhanced messages, or montelukast with neutral messages) or to usual care. Assignment to study drug was double masked, assignment to message content was single masked, and usual care was not masked. The enhanced message aimed to increase expectation of benefit from the drug. The primary outcome was mean change in daily peak flow over 4 weeks. Secondary outcomes included lung function and asthma symptom control. Peak flow and other lung function measures were not improved in participants assigned to the enhanced message groups versus the neutral messages groups for either montelukast or placebo; no differences were noted between the neutral placebo and usual care groups. Placebo-treated participants had improved asthma control with the enhanced message but not montelukast-treated participants; the neutral placebo group did have improved asthma control compared with the usual care group after adjusting for baseline difference. Headaches were more common in participants provided messages that mentioned headache as a montelukast side effect. Optimistic drug presentation augments the placebo effect for patient-reported outcomes (asthma control) but not lung function. However, the effect of montelukast was not enhanced by optimistic messages regarding treatment effectiveness.

Similar colds in subjects with allergic asthma and nonatopic subjects after inoculation with rhinovirus-16

Rhinovirus infections are frequent causes of asthma exacerbations. This study was conducted to test whether subjects with and without allergic asthma have different responses to infection and to identify baseline patient risk factors that predict cold outcomes. Twenty subjects with mild persistent allergic asthma and 18 healthy subjects were experimentally inoculated with rhinovirus-16. Subjects were evaluated at baseline, during the acute infection, and during recovery for asthma and cold symptoms by using a validated questionnaire. Sputum and nasal lavage fluid were evaluated for viral shedding, cytokines, and cellular inflammation. There were no group-specific significant differences in peak cold symptom scores (10.0 +/- 5.8 vs 11.1 +/- 6.2, asthmatic vs healthy subjects), peak nasal viral titers (log(10) 4.3 +/- 0.8 vs 3.7 +/- 1.4 50% tissue culture infective dose/mL, respectively), or changes in peak flow during the study (10% +/- 10% vs 8% +/- 6%, respectively). Rhinovirus-16 infection increased peak asthma index values in the asthmatic group (median, 6 --> 13; P = .003) but only marginally in the healthy group (median, 4 --> 7; P = .09). More asthmatic subjects had detectable eosinophils in nasal lavage and sputum samples at baseline and during infection, but otherwise, cellular and cytokine responses were similar. Baseline sputum eosinophilia and CXCL8 (IL-8) levels were positively associated with cold symptoms, whereas CCL2 (monocyte chemotactic protein 1) levels were inversely associated with nasal viral shedding. These findings suggest that subjects with mild allergic asthma and healthy subjects have similar cold symptoms and inflammatory and antiviral responses. In addition, eosinophilia and other selective baseline measures of airway inflammation in subjects with or without asthma might predict respiratory outcomes with rhinovirus infection.

Comparative Study of Budesonide Inhalation Suspension and Montelukast in Young Children With Mild Persistent Asthma

Szefler SJ, Baker JW, Uryniak T, Goldman M, Silkoff PE. J Allergy Clin Immunol. 2007;120(5):1043–1050 PURPOSE OF THE STUDY. To evaluate the efficacy of budesonide inhalation suspension (Pulmicort respules) compared with montelukast (Singulair) for controlling asthma symptoms in young children with mild persistent asthma. STUDY POPULATION. This was a prospective study of 395 children, aged 2 to 8 years, diagnosed with mild persistent asthma recruited from 55 US centers. Approximately 12% of the subjects had previous histories of inhaled corticosteroid (ICS) use. METHODS. Subjects were randomly assigned to receive either budesonide 0.5 mg or montelukast 4 to 5 mg daily and were followed for 52 weeks. Compliance was assessed by daily electronic diary review. For mild asthma exacerbations, step-up therapy consisted of the addition of a morning dose of budesonide 0.5 mg in both arms. For severe asthma exacerbations, subjects received a 3- to 10-day standardized course of oral steroids. The primary end point was evaluated by using the intention-to-treat population and was defined as time to first additional medication for asthma worsening at 52 weeks. Secondary end points included the time to additional asthma medication and rates of occurrence of mild and severe asthma exacerbations. Changes in symptom scores, peak flows, rescue-medication use, and pulmonary-function test results were also evaluated. RESULTS. Kaplan-Meier probability curves showed that the primary outcome measurement, time to the first additional asthma medication, was not significantly different between the 2 groups at 52 weeks (P = .3). There was a significant increase in the time to first additional asthma medication in the budesonide group compared with the montelukast group at 12 weeks (P = .05). The percentage of subjects requiring step-up therapy in the budesonide group versus the montelukast group at 12 weeks was 29.1% versus 38.6% (not significant [NS]), at 26 weeks was 41.3% versus 48.2% (NS), and at 52 weeks was 52% versus 56.9% (NS), respectively. The budesonide group achieved significantly improved morning and evening peak flow values compared with the montelukast group at 12 weeks (P = .005–.007). The rate of mild and severe asthma exacerbations per subject per year in the budesonide and montelukast groups was 1.23 and 1.63, respectively (P = .034). There was no significant difference in the number of severe asthma exacerbations between the 2 groups. Both treatment groups showed nonsignificant improvements in changes from baseline asthma scores, 24-hour rescue-medication use, and medication- and asthma-free days. CONCLUSIONS. Both budesonide and montelukast are effective and well-tolerated as controller medications in children aged 2 to 8 years with mild persistent asthma. Results favored budesonide for several secondary outcome measures. REVIEWER COMMENTS. Previous studies have shown that ICSs are more effective asthma-controller medications compared with montelukast in children older than 6 years. Although this study failed to show statistical significance in the primary outcome, it provides data supporting certain treatment benefits of ICSs in children younger than 6 years (257 of 395 children were &amp;lt;5 years old). Compared with previous studies, these children had milder asthma, with only 12% having taken ICSs before enrollment.

Simulated potential effects of ecological factors on a hypothetical population of Chiricahua leopard frog ( Rana chiricahuensis)

Simulations provide an opportunity to examine how single or multiple perturbations may impact a specific species. The objectives of this study were to identify thresholds at which changes in stream peak flow, stream base flow, and/or chytrid fungus presence alter long-term Rana chiricahuensis populations. We used scenarios with varying peak flow mortality rates, base flow mortality rates, and chytrid fungus mortality rates. Sensitivity analysis was also conducted. Over 50 years, populations in six scenarios increased and 13 scenarios decreased. Eight scenarios resulting with fewer than 100 individuals included stochastic effects for at least two of three perturbations and the remaining scenarios included chronic effects of 30% or higher. Scenarios with population increases had either no chytrid fungus effect or chronic effects from perturbations totaling less than 30%. In the absence of chytrid fungus, populations increased and became stable. At a 10% annual death rate caused by chytrid fungus, the R. chiricahuensis population decreased 46.8%. At a 20% death rate, the population decreased 98.6%. Model scenarios were sensitive to peak flow death rates. As peak flow mortality increased to 10 and 20%, extinction rates increased to 91.7 and 99.9%, respectively. With model parameters and the no base flow mortality, R. chiricahuensis populations declined by 92% with a 3.2% extinction rate at 50 years. Models with base flow mortality rates of 10 and 20% resulted in population extinction rates of 48.7 and 96.1%, respectively. Scenario analysis of perturbations on a hypothetical R. chiricahuensis population provided a framework in which to view combined effects on a species. Analysis supports supposition that chytrid fungus is the proximate cause of many amphibian declines, but the added effect of base flow and peak flow has the potential to hasten declines.

The association of coronary flow changes and inflammatory indices to ischaemia–reperfusion microvascular damage and left ventricular remodelling

The aim of this study was to investigate the effect of coronary flow (CF) changes and inflammatory indices on myocardial microcirculation--assessed by myocardial contrast echocardiography (MCE)--and on left ventricular remodelling, in an experimental ischaemia-reperfusion model. In 15 pigs, weighing 30 +/- 5 kg, ligation of the left anterior descending (LAD) coronary artery was performed, followed by reperfusion for 120 min. Peak, mean, duration and volume of systolic and diastolic components of CF distal to the LAD ligation were measured using a butterfly flowmeter and their ratio was calculated. The following two-dimensional echocardiography indices of LV geometry/function were measured from the apical four-chamber view: LV end-systolic (ESD) and end-diastolic (EDD) dimension long- (Ls, Ld) and short-axis (Ss, Sd) and their ratio (Ld/Sd, Ls/Ss, defined as the sphericity index). Interleukin (IL) 1beta, 6, 10 and tumour necrosis factor (TNF) were measured in samples obtained from the LV cavity and coronary sinus. A 0.5 ml/min injection slow bolus over 30 s of SonoVue was made into the left ventricle (LV) in order to assess myocardial perfusion by MCE. Standard apical four-chamber views were digitally acquired and stored for off-line analysis using the Echofit system. The peak intensity (Ac) of the microbubbles at the apex, distally to ligation, was normalised with respect to the peak intensity of the microbubbles in the LV cavity. All parameters were recorded at baseline, immediately after ligation and at 5, 15, 30, 60, 120 min during reperfusion. The percentage changes of CF indices, echocardiographic parameters, interleukins and Ac between baseline and reperfusion were calculated. Mean systolic CF, systolic volume, peak and mean diastolic flow (MDF) changes and epicardial mean CF, Ld/Sd, Ls/Ss changes and coronary sinus IL-6 (IL-6 cs) were inversely correlated with Ac changes during reperfusion. At 5 and 15 min of reperfusion (hyperaemic phase), the greatest median increase of mean diastolic (172% and 86%), and mean systolic CF (713% and 344%) and the greatest reduction of Ac (-41% at 5 min) compared to baseline (P < 0.05) were observed. The maximum increase of IL-6 cs (40%) was detected at 120 min. ROC analysis showed that of all examined echocardiography indices an increase of mean diastolic CF > 22% was the best predictor of a >25% reduction of Ac with 76% sensitivity and 65% specificity (area 71%, CI 54%-85%, P = 0.02). In addition an >32% increase of IL-6 at 120 min of reperfusion predicted a >25% reduction of Ac with a 76% sensitivity and 65% specificity (area 71% CI 61%-97%, P = 0.01). Changes of mean diastolic CF and IL-6 cs are associated with alterations in myocardial microvascular integrity after ischaemia-reperfusion and may be used as a predictor of myocardial dysfunction.

Hydrological response to timber harvest in northern Idaho: implications for channel scour and persistence of salmonids

AbstractThe potential for forest harvest to increase snowmelt rates in maritime snow climates is well recognized. However, questions still exist about the magnitude of peak flow increases in basins larger than 10 km2 and the geomorphic and biological consequences of these changes. In this study, we used observations from two nearly adjacent small basins (13 and 30 km2) in the Coeur d'Alene River basin, one with recent, relatively extensive, timber harvest, and the other with little disturbance in the last 50 years to explore changes in peak flows due to timber harvest and their potential effects on fish. Peak discharge was computed for a specific rain‐on‐snow event using a series of physical models that linked predicted values of snowmelt input to a runoff‐routing model. Predictions indicate that timber harvest caused a 25% increase in the peak flow of the modelled event and increased the frequency of events of this magnitude from a 9‐year recurrence interval to a 3·6‐year event. These changes in hydrologic regime, with larger discharges at shorter recurrence intervals, are predicted to increase the depth and frequency of streambed scour, causing up to 15% added mortality of bull trout (Salvelinus confluentus) embryos. Mortality from increased scour, although not catastrophic, may have contributed to the extirpation of this species from the Coeur d'Alene basin, given the widespread timber harvest that occurred in this region. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Premenstrual Asthma: Prevalence, Cycle-to-Cycle Variability and Relationship to Oral Contraceptive Use and Menstrual Symptoms

The prevalence of asthma is higher in women than men of reproductive age and almost half of all hospitalisations for asthma in women occur during the perimenstrual phase of the cycle. The mechanisms of premenstrual asthma (PMA) are unknown and a definition of PMA has not been clearly presented in the literature. The objective of this study was to determine the prevalence of PMA using a variety of definitions, to investigate the cycle-to-cycle variation in PMA, the effects of oral contraceptive use and the relationship between PMA and premenstrual symptoms. Premenopausal women with asthma (n = 28) were prospectively followed for at least 12 weeks over 2–4 consecutive menstrual cycles. Asthma symptoms, β2-agonist and inhaled corticosteroid use and morning and evening peak expiratory flow were recorded daily. The following types of PMA definitions were investigated: self-reported PMA, increased symptoms, increased medication use, decreased peak flow or a combination of changes in symptoms, medication and peak flow. Changes of more than 20%, for at least 2 consecutive days of the luteal phase (last 14 days of the cycle prior to menstruation) compared to the early follicular phase average (first 7 days after menstruation) were considered PMA. Using a composite definition where subjects experienced increased symptoms and medication use with or without a change in peak flow, 16 subjects were classified as having PMA (57%), while 12 did not have PMA. Only 4 subjects (25%) had PMA in every cycle examined. Fifty-five percent of subjects who used oral contraceptives had PMA, while 59% of subjects who did not use oral contraceptives had PMA. Women who were defined PMA using the composite definition were more likely than those without PMA to experience a 20% decrease in peak flow during the luteal phase. There was no relationship between asthma symptoms and premenstrual symptoms on day 1 of the menstrual cycle in women with PMA. PMA resulting in increased symptoms and medication use occurred in 57% of subjects studied for 2–4 menstrual cycles. The use of oral contraceptives is not protective and further work is required to elucidate the mechanisms of PMA.

Use of the Airway Questionnaire 20 to Detect Changes in Quality of Life in Asthmatic Patients and its Association with the St George’s Respiratory Questionnaire and Clinical Parameters

The usefulness of the Airway Questionnaire 20 (AQ20) -- a short version of the St George's Respiratory Questionnaire (SGRQ) -- to evaluate quality of life (QOL) in asthmatic patients following a hospital admission was assessed. At baseline and at six months following the index admission, 135 asthmatic patients were asked to complete the AQ20 and the SGRQ. The patient's peak flow, number of subsequent asthma exacerbations and number of repeat hospital admissions were also recorded. The AQ20 scores ranged from 0 to 20, with a high score indicating poor QOL. The AQ20 had good coverage, with no obvious ceiling or floor effects. In multiple regression analysis, all three SGRQ components were important in predicting AQ20 scores (R(2) values were 61.9% and 73.1% for baseline and six-month scores, respectively). The AQ20 was closely correlated with the SGRQ, but not redundant when used together. Bias was low when the retest reliability of the AQ20 was evaluated using the Bland-Altman method, but variation was high (-0.64). Patients with subsequent exacerbations (n=52) had higher AQ20 scores at six-month follow-up (P=0.002). In logistic regression, the AQ20 score was closely associated with the incidence of exacerbations (OR 1.15, 95% CI 1.05 to 1.25), with a similar magnitude of association between the AQ20 and the SGRQ. The AQ20 score did not correlate with peak flow at baseline (r=-0.05; P=0.573) or at six months (r=-0.31; P=0.006), and was not responsive to changes in peak flow (r=-0.06; P=0.583). The AQ20 can be substituted for the more complicated SGRQ in the assessment of QOL in patients following a hospital admission for an asthma exacerbation.

Do shrimp‐allergic individuals tolerate shrimp‐derived glucosamine?

There is concern that shrimp-allergic individuals may react to glucosamine-containing products as shrimp shells are a major source of glucosamine used for human consumption. The purpose of this study was to determine whether shrimp-allergic individuals can tolerate therapeutic doses of glucosamine. Subjects with a history of shrimp allergy were recruited and tested for both shrimp reactivity via a prick skin test and shrimp-specific IgE by an ImmunoCAP assay. Fifteen subjects with positive skin tests to shrimp and an ImmunoCAP class level of two or greater were selected for a double-blind placebo-controlled food challenge (DBPCFC) using glucosamine-chondroitin tablets containing 1,500 mg of synthetically produced (control) or shrimp-derived glucosamine. Immediate reactions, including changes in peak flow and blood pressure, and delayed reactions (up to 24 h post-challenge) via questionnaire were noted and assessed. All subjects tolerated 1,500 mg of both shrimp-derived or synthetic glucosamine without incident of an immediate hypersensitivity response. Peak flows and blood pressures remained constant, and no subject had symptoms of a delayed reaction 24 h later. This study demonstrates that glucosamine supplements from specific manufacturers do not contain clinically relevant levels of shrimp allergen and therefore appear to pose no threat to shrimp-allergic individuals.

Effect of Psychological Intervention on Exercise Adherence in Type 2 Diabetic Subjects

Previous research has pointed to the efficacy of physical activity in individuals suffering from type 2 diabetes mellitus (type 2 DM). However, as with other populations, adherence to exercise programs is often problematic. This study assessed the effectiveness of a combination of exercise and psychological interventions in type 2 diabetics in terms of disease management and exercise adherence. Forty newly diagnosed type 2 diabetic subjects (54 +/- 6.5 years) took part in the study. Subjects were allocated to an exercise-only intervention (EO) or a combined exercise and psychological adherence intervention (EP) group. Adherence to the program was also monitored at a 6-month follow-up. The results confirmed a significant improvement in physiological parameters (total mass, fat mass, grip strength, peak flow, flexibility, and VO2 max) after the 12-week program in both groups (P < 0.001). The EP group had significant changes in body fat, grip strength, and peak flow (P < 0.05) in comparison to the EO group. Components of the visual analog mood scale (VAMS) were positively influenced in both groups from the therapy program (P < 0.001). The directed psychological intervention had a significant influence on attendance to the 12-week program (P < 0.001). This also resulted in significantly better adherence 6 months later (P < 0.05). In conclusion, the results have demonstrated that psychological intervention is of paramount importance for ensuring high adherence rates during exercise therapy for type 2 diabetic subjects.

COMPARISON OF SERIAL CHANGE IN PULMONARY ARTERY PRESSURES IN VARIOUS FORMS OF ADVANCED LUNG DISEASE

To evaluate whether follow-up of patients recently discharged from the hospital as a result of acute asthma can be adequately provided by a respiratory specialist nurse compared to a respiratory doctor.Single center, prospective, randomized controlled trial.District general hospital in the United Kingdom.One hundred fifty-four of 373 eligible patients admitted with acute asthma were enrolled into the study from October 2000 to October 2003. All patients > 16 years of age were eligible for the study. Patients with COPD were excluded.Patients were randomly assigned to receive an initial 30-min follow-up clinic appointment within 2 weeks of hospital discharge with either a specialist nurse or respiratory doctor. This comprised a medical review, patient education, and a self-management asthma plan. Further follow-up was then arranged as was deemed appropriate by the corresponding doctor or nurse. All patients were asked to attend a 6-month appointment.The primary outcome was the number of exacerbations within 6 months of hospital admission. Secondary outcome variables were change in peak flow, quality of life (using the St. George Respiratory Questionnaire (SGRQ) and the Asthma Questionnaire 20 [AQ20]), and clinic attendance.Outcome data were available for 66 patients in the doctor group and 70 patients in the nurse group. There was no difference in the number of patients with exacerbations in the nurse group compared to the doctor group (45.6% vs 49.2%; odds ratio, 0.86; 95% confidence interval [CI], 0.44 to 1.71; p = 0.674). However, a significant proportion of patients in both groups had exacerbations despite hospital outpatient follow-up. There was no difference in quality of life (p = 0.285; mean difference, 0.78; 95% CI, - 0.64 to 2.19 for the AQ20; and p = 0.891; mean difference, 1.08; 95% CI, - 5.05 to 7.21 for SGRQ) or change in peak flow (mean difference between nurse and doctor groups, 1.39 (95% CI, - 3.84 to 6.63; p = 0.122) at 6 months.Follow-up care by a nurse specialist for patients admitted with acute asthma can be delivered equivocally with comparable safety and effectiveness to that given by a doctor.

The prognosis of occupational asthma due to detergent enzymes: clinical, immunological and employment outcomes

Little is known about the prognosis of occupational asthma induced by high molecular weight proteins. Our objective was to measure the clinical, immunological and employment outcomes of individuals with occupational asthma induced by detergent enzymes. We undertook a workforce-based follow-up study in 35 (78%) of the 45 ex-employees from a single factory with occupational asthma. In each case the diagnosis was supported by evidence of specific sensitization and characteristic changes in peak flow or a positive response to specific bronchial provocation testing. This group had left the factory on average 37 months before study. On review 25 (71%) reported chest symptoms during the last month. Compared with when working at the factory, most (86%) reported that their symptoms had improved. Twenty continued to attend their general practitioner for respiratory symptoms and 19 still used asthma medications. Since leaving the factory 16 (46%) and four (11%) had found full-time or part-time employment, respectively; of these 16 found they were paid less than when they worked at the factory. The remaining 15 subjects had not had any paid employment. All but two had positive skin prick tests to one or more three detergent enzymes. The estimated half-life of serum-specific IgE antibodies was 20 months for protease, and 21 months for cellulase and amylase. Population-based follow-up studies of the prognosis of occupational asthma are rare but probably avoid the bias in clinic-derived surveys. This study demonstrates that 3 years after the avoidance of exposure with detergent enzymes most patients continue to be troubled by, albeit improved, symptoms and experience difficulty in re-employment.

Change In Plasma C5a Levels After Routine Allergen Immunotherapy Correlates With Dust Mite Dosage, Changes in Wheal Size, And Rhinoconjunctivitis Symptoms

RATIONALE: Complement split product C5a is increased in BAL fluid after segmental allergen provocation. C5a also is generated in vitro in serum in the presence of allergens. This study investigated if plasma C5a levels are altered after routine allergen immunotherapy (IT) for rhinitis/asthma.METHODS: C5a-desArg levels in plasma (ELISA) from IT subjects (n=16) were determined immediately before and 1 hr after IT. Skin reactivity to each allergen (induration) was determined at 15 min and 1 hr. Spirometry was performed before and at 1 hr. Rhinoconjunctivitis quality of life symptom scores (RQLQ, Juniper) and total serum IgE level were determined.RESULTS: Change in plasma C5a levels was found to correlate with change in total mean wheal diameter (p=0.05), total dust mite IT dose(p=0.04), and total RQLQ score (p=0.03). Change in C5a did not correlate with total IT dose or IgE.Although change in C5a levels did not correlate with spirometric parameters at 1 hr, there was a significant negative correlation between total mean wheal diameter change and change in peak flow (PEFR)(p=0.005). The mean change in wheal diameter induced by dust mite IT was negatively correlated with change in FEF25-75 (p=0.007), but not PEFR (p=0.4).CONCLUSIONS: The correlation of change in C5a levels with dust mite dosage, changes in wheal size, and symptoms scores strongly suggests that C5a is crucial in the maintenance of allergic inflammation. RATIONALE: Complement split product C5a is increased in BAL fluid after segmental allergen provocation. C5a also is generated in vitro in serum in the presence of allergens. This study investigated if plasma C5a levels are altered after routine allergen immunotherapy (IT) for rhinitis/asthma. METHODS: C5a-desArg levels in plasma (ELISA) from IT subjects (n=16) were determined immediately before and 1 hr after IT. Skin reactivity to each allergen (induration) was determined at 15 min and 1 hr. Spirometry was performed before and at 1 hr. Rhinoconjunctivitis quality of life symptom scores (RQLQ, Juniper) and total serum IgE level were determined. RESULTS: Change in plasma C5a levels was found to correlate with change in total mean wheal diameter (p=0.05), total dust mite IT dose(p=0.04), and total RQLQ score (p=0.03). Change in C5a did not correlate with total IT dose or IgE. Although change in C5a levels did not correlate with spirometric parameters at 1 hr, there was a significant negative correlation between total mean wheal diameter change and change in peak flow (PEFR)(p=0.005). The mean change in wheal diameter induced by dust mite IT was negatively correlated with change in FEF25-75 (p=0.007), but not PEFR (p=0.4). CONCLUSIONS: The correlation of change in C5a levels with dust mite dosage, changes in wheal size, and symptoms scores strongly suggests that C5a is crucial in the maintenance of allergic inflammation.