Predictive markers of asthma exacerbation during stepwise dose reduction of inhaled corticosteroids

To determine predictors for failed reduction of inhaled corticosteroids (ICS), in 50 subjects with well-controlled asthma (age 43.7 [18-69]; 22 males) taking a median dose of 1,000 microg ICS/d (100-3,600 microg/d), ICS were halved every 8 wk. Airway hyperresponsiveness (AHR) to a bronchial provocation test (BPT) with histamine was measured at baseline. AHR to BPT with mannitol, spirometry, exhaled nitric oxide (eNO), and, in 31 subjects, sputum inflammatory cells were measured at baseline and at monthly intervals. Thirty-nine subjects suffered an asthma exacerbation. Seven subjects were successfully weaned off ICS. Using a Kaplan- Meier survival analysis, the significant predictors of a failure of ICS reduction were being hyperresponsive to both histamine and mannitol at baseline (p = 0.039), and being hyperresponsive to mannitol during the dose-reduction phase of the study (p = 0.02). Subjects older than 40 yr of age tended to be at greater risk of ICS reduction failure (p = 0.059). Response to mannitol and percentage sputum eosinophils were significantly greater before a failed ICS reduction than before the last successful ICS reduction, whereas there were no significant differences in symptoms, spirometry, or eNO. These findings suggest that documentation of patient's AHR or sputum eosinophils may be useful in guiding the reduction of ICS doses.

Consumption of oily fish and childhood asthma risk

OBJECTIVE

To investigate the association between diet and airway disease in children in the light of epidemiological studies suggesting that consumption of fish more than once a week reduces the risk of developing airway hyperresponsiveness (AHR).

DESIGN

Diet was assessed by a detailed food frequency questionnaire and airway disease by respiratory symptoms or airway responsiveness to exercise.

METHODS

A questionnaire, containing questions about the frequency of eating more than 200 foods, was sent to the parents of 574 children in whom we had measured recent wheeze (by questionnaire), AHR (by exercise) and atopy (by skin prick tests) six months before this study. We defined current asthma as the presence of both recent wheeze and AHR.

RESULTS

Response rate to the questionnaire was 81.5% (n=468.) After adjusting for confounders such as sex, ethnicity, country of birth, atopy, respiratory infection in the first two years of life and a parental history of asthma or smoking, children who ate fresh, oily fish (>2% fat) had a significantly reduced risk of current asthma (odds ratio, 0.26; 95% confidence interval, 0.09-0.72; P<0.01). No other food groups or nutrients were significantly associated with either an increased or reduced risk of current asthma.

CONCLUSION

These data suggest that consumption of oily fish may protect against asthma in childhood.

Clinical importance of Alternaria exposure in children

The fungus Alternaria is known to be allergenic and is one of the most common fungi worldwide. We investigated the extent to which exposure to Alternaria increases the severity of asthma. We undertook a prospective cohort study in Australia of 399 school children who had positive skin tests to one or more aeroallergens. Airway responsiveness to histamine, wheeze, and bronchodilator use in 1 mo was measured five times between 1997 and 1999. Airway hyperresponsiveness was defined as PD(20)FEV(1) = 3.9 micromol histamine. Airborne concentrations of Alternaria spores were measured throughout the study, and mean daily concentrations over 1 mo ranged from 2.2 to 307.7 spores/m(3) of ambient air. Using generalized estimating equations, we found that airway responsiveness, wheeze, and bronchodilator use increased significantly in association with increased spore concentrations and that the increase in airway responsiveness was greater in children sensitized to Alternaria than in other children (p = 0.01). The odds ratio for airway hyperresponsiveness in children sensitized to Alternaria was 1.26 (95% CI, 1.14 to 1.39) after an increase in mean exposure of 100 spore/m(3)/d over 1 mo. These results suggest that Alternaria allergens contribute to severe asthma in regions where exposure to the fungus is high.

Meta-analysis on the association between environmental tobacco smoke (ETS) exposure and the prevalence of lower respiratory tract infection in early childhood

The aim of this study was to obtain quantitative information from published data on the association between environmental tobacco smoke (ETS) exposure and the prevalence of serious lower respiratory tract infections (LRTI) in infancy and early childhood. We identified 21 relevant publications on the relation between ETS and the prevalence of serious LRTI by reviewing reference lists in relevant reports and by conducting manual and computer searches (Medline database; Dissertation abstracts index of Xerox University Microfilms) of published reports between 1966 and 1995. Thirteen studies were included in a quantitative overview using random effects modeling to derive pooled odds ratios. Sensitivity analyses were conducted to test the decision rules used in extracting odds ratio data. The results of community and hospital studies are broadly consistent and show that the child of a parent who smokes is at approximately twice the risk of having a serious respiratory tract infection in early life that requires hospitalization. This association was pronounced in children younger than age two and diminished after the age of two. The combined odds ratio for hospitalization for lower respiratory tract infections in infancy or early childhood is 1.93 (95% CI 1.66-2.25); the combined odds ratio of prevalence of serious LRTI at age less than 2 years, between 0 and 6 years, and between 3 and 6 years were 1.71 (95% CI 1.33-2.20); 1.57 (1.28-1.91), and 1.25 (0.88-1.78), respectively. There was no evidence of heterogeneity across the studies in these combined odds ratios. We conclude that this meta-analysis provides strong evidence that exposure to ETS causes adverse respiratory health outcomes such as either a serious LRTI or hospitalization for LRTI. New public health campaigns are urgently needed to discourage smoking in the presence of young children.

Optimal asthma control, starting with high doses of inhaled budesonide

The aim of this study was to determine whether outcomes in poorly controlled asthma can be further improved with a starting dose of inhaled budesonide higher than that recommended in international guidelines. The study had a parallel-group design and included 61 subjects with poorly controlled asthma, randomized to receive 3,200 microg or 1,600 microg budesonide daily by Turbuhaler for 8 weeks (double-blind), then 1,600 microg x day(-1) for 8 weeks (single-blind), followed by 14 months of open-label budesonide dose down-titration using a novel algorithm, with a written asthma crisis plan based on electronic peak expiratory flow monitoring. The primary outcome variable for weeks 1-16 was change in airway hyperresponsiveness (AHR), and, for the open-label phase, mean daily budesonide dose. By week 16, there were large changes from baseline in all outcomes, with no significant differences between the 3,200- and 1,600-microg x day(-1) starting dose groups (AHR increased by 3.2 versus 3.0 doubling doses, p=0.7; morning peak flow increased by 134 versus 127 L x min(-1), p=0.8). Subjects starting with 3,200 microg x day(-1) were 3.8 times more likely to achieve AHR within the normal range, as defined by a provocative dose of histamine causing a 20% fall in forced expiratory volume in one second (PD20) of > or = 3.92 micromol by week 16 (p=0.03) [corrected]. During dose titration, there was no significant difference in mean budesonide dose (1,327 versus 1,325 microg x day(-1), p>0.3). Optimal asthma control was achieved in the majority of subjects (at completion/withdrawal: median symptoms 0.0 days x week(-1), beta2-agonist use 0.2 occasions x day(-1), and PD20 2.4 micromol). In subjects with poorly controlled asthma, a starting dose of 1,600 microg x day(-1) budesonide was sufficient to lead to optimal control in most subjects. The high degree of control achieved, compared with previous studies, warrants further investigation.

Early predictors for developing allergic disease and asthma: examining separate steps in the 'allergic march'

BACKGROUND

Sensitization and symptoms of allergic disease are strongly correlated, but little is known about the early clinical precursors of the development of allergen sensitization in childhood. The aim of this study was to identify these predictors, and to examine separately the effect of early sensitization on subsequent wheeze, asthma, rhinitis and eczema.

METHODS

In the Childhood Asthma Prevention Study, children with a family history of asthma were assessed for allergen sensitization, total serum IgE, wheeze, asthma, eczema and rhinitis at ages 18 months and 5 years. To examine predictors, at 18 months, for subsequent sensitization, children who were non-sensitized at 18 months and had data on sensitization at 5 years were investigated, n=375. To examine the predictors, at age 18 months, of subsequent onset of symptoms, children who did not have wheeze, asthma, eczema or rhinitis at 18 months were followed-up at 5 years, n=177.

RESULTS

Among children who were non-sensitized at age 18 months, the presence of eczema [adjusted relative risk (aRR), 1.67, 95% confidence interval (CI) 1.20-2.33], but not wheeze, asthma or rhinitis, was an independent predictor of the onset of sensitization by age 5 years. Among children who were asymptomatic at age 18 months, sensitization to any allergen at 18 months was an independent predictor for the presence of wheeze (aRR 2.41, 95% CI 1.28-4.55), asthma (aRR 4.66, 95% CI 1.88-11.54) and rhinitis (aRR 1.77, 95% CI 1.08-2.90), but not for the development of eczema (aRR 0.78, 95% CI 0.23-2.64) at 5 years.

CONCLUSION

In non-sensitized children, eczema, but not wheeze, asthma or rhinitis is a predictor for subsequent development of sensitization. This suggests that early childhood eczema, rather than wheeze and rhinitis, may promote subsequent allergen sensitization and raises the possibility that early management of eczema may reduce the prevalence of sensitization in children.

Lung function growth and its relation to airway hyperresponsiveness and recent wheeze. Results from a longitudinal population study

To evaluate the association between growth in height and growth in lung function, and to identify the potential temporal relationships between airway hyperresponsiveness (AHR), respiratory symptoms, and lung function growth during adolescence and young adulthood, we analyzed data collected from the Belmont cohort. Among the 718 schoolchildren initially studied at 1982 (aged 8-10 yr), 557 were studied between two times and six times at 2-yr intervals until 1992. Baseline lung function, AHR by histamine inhalation test, and recent wheeze by questionnaires, were measured at each visit. We found that between 17 and 19 yr of age, when growth in height had stopped, growth in FEV(1) was approximately 200 ml/yr in boys and 100 ml/yr in girls. Peak growth velocity of height occurred at age 13 both in boys and in girls, whereas peak growth velocity of FEV(1) occurred at the same age only in girls and 1 yr later in boys. Having AHR and recent wheeze at the previous study time were both associated with lower subsequent growth in FEV(1), but not with subsequent growth in FVC. We conclude that lung function continues to grow after the cessation of height growth and that growth in FEV(1) is reduced in subjects with AHR and/or recent wheeze.

Symptoms of persistent allergic rhinitis during a full calendar year in house dust mite-sensitive subjects

BACKGROUND

Little is known about the natural course of persistent rhinitis symptoms over a prolonged period.

OBJECTIVE

To describe the frequency and severity of nasal symptoms and quality of life (QoL) in house dust mite-sensitive persistent rhinitic subjects and to determine if medication use was related to symptoms.

METHODS

Rhinitics and controls were telephoned fortnightly for 1 year to monitor symptoms. QoL was measured every 3 months.

RESULTS

Thirty-seven rhinitics and 19 controls completed the study. Total nasal symptom scores (TNSS) were 'high' for 65% (95% CI +/- 6%) of the year in rhinitic subjects. When TNSS increased by 1, the likelihood of nasal medication use increased by 25% (95% CI: 7-46%). General and specific QoL were worse in rhinitic subjects than controls (P < 0.04 and <0.0001). Rhinitics with pollen allergy (n = 21) had seasonal variation in the frequency of high nasal symptom scores (P = 0.02).

CONCLUSION

Nasal symptom scores were consistently high in rhinitics, and their QoL was worse than controls, even in general QoL. An increase in nasal symptom score increased the likelihood of nasal medication use. These findings help to characterize the course of persistent rhinitis over a previously unstudied period of 1 year.

Risk factors for onset and remission of atopy, wheeze, and airway hyperresponsiveness

BACKGROUND

Although many children with asthma may have a remission as they grow and other children who did not have asthma may develop asthma in adult life, knowledge about the factors that influence the onset and prognosis of asthma during adolescence and young adulthood is very limited.

METHODS

A cohort of 8-10 year old children (n=718) living in Belmont, New South Wales, Australia were surveyed six times at 2 yearly intervals from 1982 to 1992, and then again 5 years later in 1997. From this cohort, 498 subjects had between three and seven assessments and were included in the analysis. Atopy, airway hyperresponsiveness (AHR), and wheeze in the last 12 months were measured at each survey. Late onset, remission, and persistence were defined based on characteristics at the initial survey and the changes in characteristics at the follow up surveys.

RESULTS

The proportion of subjects with late onset atopy (13.7%) and wheeze (12.4%) was greater than the proportion with remission of atopy (3.2%) and wheeze (5.6%). Having atopy at age 8-12 years (OR 2.8, 95% CI 1.5 to 5.1) and having a parental history of asthma (OR 2.0, 95% CI 1.02 to 4.13) were significant risk factors for the onset of wheeze. Having AHR at age 8-12 years was a significant risk factor for the persistence of wheeze (OR 4.3, 95% CI 1.3 to 15.0). Female sex (OR 1.9, 95% CI 1.01 to 3.60) was a significant risk factor for late onset AHR whereas male sex (OR 1.9, 95% CI 1.1 to 2.8) was a significant risk factor for late onset atopy.

CONCLUSIONS

The onset of AHR is uncommon during adolescence, but the risk of acquiring atopy and recent wheeze for the first time continues during this period. Atopy, particularly present at the age of 8-10 years, predicts the subsequent onset of wheeze.

Childhood factors that predict asthma in young adulthood

Predicting adult asthma, using childhood characteristics, is important for advising on prognosis and, potentially, for secondary prevention. A novel use of multivariate likelihood ratios (LRs) to quantify prognosis is described here. Of 718 subjects of a community-based cohort, 575 (80%) members were recruited at age 8-10 yrs and were re-assessed 15-17 yrs later. At baseline, information about symptoms, spirometry, histamine challenge and skin-prick tests were collected. At follow-up "asthma symptoms" were defined as wheeze, sleep disturbance from asthma or inhaled steroid use within the previous year. LRs were calculated for significant predictors of this outcome. Shinkage factors were applied to yield multivariate LRs. Childhood characteristics that independently predicted asthma symptoms in adulthood were obstructive spirometry (adjusted (adj)LR 2.9, 95% confidence interval (CI) 1.3-6.5), airway hyperresponsiveness (adjLR 2.6, 95% CI 1.8-3.7), atopy (adjLR 2.0, 95% CI 1.5-2.7), recent wheeze (adjLR 1.9, 95% CI 1.5-2.5) and being female (adjLR 1.29, 95% CI 0.8-2.1). Children with all five characteristics had a cumulative LR of 36.9 for asthma symptoms in adulthood. Most adults who had asthma symptoms did not have manifestations of asthma as children. However, the presence of obstructive spirometry, airway hyperresponsiveness and atopy in childhood identifies individuals with increased likelihood of having asthma in adulthood. Cumulative likelihood ratios are more valuable than odds ratios for quantifying risk in individuals and for identifying people with most to gain from preventive interventions.

Personal exposure to allergenic pollen and mould spores in inland New South Wales, Australia

BACKGROUND

In inland NSW, Australia, allergic sensitization to the fungi Alternaria and Cladosporium and to pollen is common and an important risk factor for asthma.

OBJECTIVE

We report the results of a series of experiments designed to assess the nature of personal exposure to these airborne allergenic particles. We have tested the effect of exposure conditions and level of activity on measurements of the personal exposure.

METHOD

Personal Air Samplers (PAS) and Nasal Air Samplers (NAS) were employed. NAS are fitted just inside the nose and collect inhaled particles by impaction, while the PAS use a pump-operated filter with constant air flow (2 L/min). Thirty-three subjects (adults and children) used both NAS and PAS simultaneously for four one hour periods during which they performed activities or rested, both inside and outside their homes. Samples were analysed by light microscopy. Alternaria spores, Cladosporium spores, grass pollen and nongrass pollen were counted.

RESULTS

Both samplers detected substantial variation in exposure between subjects. Between members of the same household, the intrahouse correlation coefficient ranged from < 0 - 0.38. Levels of pollen grains and fungal spores inhaled were higher during periods of activity than during rest, and higher while subjects were outdoors than indoors. During the active outdoor period, the number of Alternaria spores inhaled ranged from 4 to 794 (median 11) spores/hr, Cladosporium from 0 to 396 (median 4) spores/hr, grass pollen from 0 to 81 (median 1) grains/hr and nongrass pollen from 0 to 72 (median 5) grains/hr.

CONCLUSION

This is the first study to quantify individual inhaled levels of allergenic fungal spores and pollen under normal domestic circumstances. Exposure can be substantial and highly variable between individuals. The amount of particles inhaled relates both to location of the individual and activity being performed, independent of age group.

The reduction of rhinitis symptoms by nasal filters during natural exposure to ragweed and grass pollen

BACKGROUND

Prototype nasal filters were developed to collect inhaled pollen. This study evaluated the efficacy of the filters for prevention of rhinitis symptoms during acute outdoor pollen exposure.

METHODS

A randomized double-blind design was used. Subjects (n=46) with a history of autumn exacerbation of rhinitis and positive skin test to ragweed, Bermuda and/or Bahia grass wore either active or placebo nasal filters for 2 h in autumn in a park containing these species. Major and Total Symptoms scores were recorded at 0, 30, 60, 90 and 120 min.

RESULTS

Subjects wearing active nasal filters had significantly reduced scores, at all time-points compared with placebo group (all P <0.05). Of 14 individual symptoms measured, seven were significantly reduced (number of sneezes, runny nose, itchy nose, sniffles, itchy throat; itchy eyes and watery eyes) and another three showed a trend towards lower severity. The nasal filters also enabled the resolution of existing symptoms. Maximal difference in symptoms was seen immediately after subjects had spent 20 min sitting beside a large patch of ragweed.

CONCLUSION

This is the first clinical trial of a nasal filter. The results suggest it has potential for enhancing rhinitis management during acute allergen exposure.

The effect of diabetes mellitus on costs and length of stay in patients with peripheral arterial disease undergoing vascular surgery

OBJECTIVE

To determine the impact of diabetes mellitus (DM) and other comorbidities on length of stay (LOS) and costs in patients with peripheral arterial disease (PAD) admitted to a vascular surgical unit.

METHODS

A retrospective study was conducted between January 2011 and July 2012 at a tertiary referral hospital in Sydney. Demographic, laboratory, and operative data were obtained from the Australasian Vascular Audit database and hospital diagnostic-related group (DRG) reports. Patients with confirmed PAD with or without DM requiring hospital admission for a diagnosis of claudication, rest pain, ulcer/gangrene, and infection that required lower limb surgical intervention were included. Associations between LOS, surgical procedure, and DRG were explored.

RESULTS

Five hundred and sixty-eight admissions (492 patients) were identified: 292 admissions with PAD and 276 admissions with PAD in conjunction with DM (PADDM). Mean LOS for patients with PAD was 10 ± 13.7 days compared with 15 ± 18.2 days for PADDM (p < .01; 95% confidence interval 2.7-8.0). LOS and costs were greatest in patients with PADDM undergoing major amputation (37 ± 13.7 days; US$42,236; p < .01). Analysis of variance indicated that the best predictors of LOS were the presence of DM, bypass surgery, amputation, chronic kidney disease (CKD) stage V, infection, and emergency admission. Over 18 months, the estimated total inpatient costs associated with lower limb intervention for PAD with and without DM amounted to US$7,598,597. People with DM incurred greater inpatient costs, averaging US$1,912 more per episode of admission and a total of US$528,029 over 18 months.

CONCLUSION

The impact of diabetes as a comorbid condition in patients with PAD is significant, both clinically and economically. Factors that predict increased LOS in patients with PAD are DM, bypass surgery, amputation, CKD stage V, infection, and emergency admission.

Association between nasal and bronchial symptoms in subjects with persistent allergic rhinitis

BACKGROUND

The association between nasal and bronchial symptoms, and the course of bronchial responsiveness and airway inflammation in house dust mite sensitive persistent rhinitis over a prolonged time period has not been thoroughly explored.

OBJECTIVE

To determine if nasal symptoms were associated with bronchial symptoms in persistent rhinitic subjects, and to assess their bronchial responsiveness and airway inflammation in comparison to nonrhinitic, nonatopic controls. The additional impact of pollen sensitivity on the lower airways in rhinitic subjects was also addressed.

METHODS

Rhinitics and controls answered telephone symptom questionnaires once every 2 weeks for 1 year. Every 3 months, exhaled nitric oxide (eNO) and bronchial responsiveness to histamine were measured.

RESULTS

Thirty-seven rhinitics and 19 controls completed the study. High nasal symptom scores in rhinitic subjects were associated with bronchial symptoms (OR = 1.7, 95% CI 1.2-2.5). Bronchial hyper-responsiveness was present in 32.4% of rhinitic subjects on at least one clinical visit during the year. Pollen allergy caused seasonal variation in eNO (P = 0.03).

CONCLUSION

In persistent rhinitic subjects, high nasal symptom scores were associated with bronchial symptoms, and many subjects experienced bronchial hyper-responsiveness during the year. Persistent rhinitic subjects were more at risk than healthy adults of bronchial symptoms and airway inflammation, which are likely risk factors for asthma.

Family patterns of asthma, atopy and airway hyperresponsiveness: an epidemiological study

BACKGROUND

The patterns of inheritance of asthma have largely been explored using data of symptom history collected by questionnaires which are subject to bias and which may therefore distort the measured relationship.

OBJECTIVE

The purpose of this study was to examine family patterns of allergic disease using objective measurements of atopy and of airway hyperresponsiveness (AHR).

METHODS

A large random sample of children aged 8-11 years was studied and 3 months later, their parents were also invited for study. Of the sample of 1655 children, both parents of 661 children were studied. In all subjects, respiratory illness history was measured by questionnaire, atopy by skin tests and AHR by responsiveness to histamine.

RESULTS

The odds ratio for a child to have AHR if either parent had the same condition was approximately 2. 0, which was the same as the odds ratio for wheeze or diagnosed asthma in the presence of the same condition in either parent. The odds ratio for atopy was smaller (approximately 1.4, NS) but the risk of a nonatopic child having AHR if the parent had AHR was 3.0 (P = 0.01). The correlation between weal size in the child and parent was poor and the severity of AHR in the child was only modestly correlated with the severity of AHR in the parent (R = 0.51, P = 0.04).

CONCLUSION

The use of objective measurements did not strengthen the association between atopic or asthmatic conditions in the parent and child, but did suggest that atopy and AHR are inherited independently.

On adjusting measurements of airway responsiveness for lung size and airway caliber

It has been suggested that during bronchial challenge with a pharmacologic agent, subjects with small lungs receive a proportionally greater dose of agonist than do those with larger lungs. This infers that measurements of airway hyperresponsiveness (AHR) between different age and gender groups may not be comparable. To examine this, we analyzed data from population samples of 1,613 children 7 to 12 yr of age and 1,484 adults 25 to 50 yr of age in whom we measured airway responsiveness by histamine inhalation test. We used FVC as a surrogate measurement for lung size and FEV1/FVC as a surrogate measurement for airway caliber. When AHR was adjusted for FVC, FEV1/FVC, and gender, the differences in prevalence between age groups was reduced. The prevalence of AHR in those between 7 and 9 yr of age decreased from 20.2% (95% CI, 17.7 to 22.7) to 15.7% (95% CI, 13.4 to 18.0), but the prevalence of AHR in those 35 to 44 yr of age remained the same at 7.6% (95% CI, 5.9 to 9.3). We conclude that FVC and FEV1/FVC have a small but significant effect on the measurement of airway responsiveness and that more precise measurements of the prevalence of AHR can be obtained by standardization for these parameters.

The effect of insecticide aerosols on lung function, airway responsiveness and symptoms in asthmatic subjects

The object of this study was to compare the effect of standard and "low irritant" insecticide aerosols on lung function, airway hyperresponsiveness (AHR) and symptoms in asthmatic subjects. A double blind randomized, crossover study was conducted in 25 asthmatic subjects who reported sensitivity to insecticide aerosols. All subjects were exposed for 30 min, on separate occasions, to two standard insecticide formulations (A and B), one low irritant formulation (C) and a negative control aerosol. Spirometric function and chest, nose and eye symptoms were recorded during, and for 90 min after, the exposure. AHR to methacholine was measured 90 min after the exposure. Compared to the negative control, the maximum fall in forced expiratory volume in one second (FEV1) was slightly greater after standard insecticides (mean differences from control +/-95% confidence interval: aerosol A, 3.3+/-3.6%, p=0.08; aerosol B, 5.1+/-4.7%, p=0.04), AHR was significantly more severe (mean difference from control: aerosol A, 0.35+/-0.29 doubling doses, p=0.028; aerosol B, 0.52+/-0.43 doubling doses, p=0.028), and symptoms were more severe. The low irritant test aerosol (C) did not differ significantly from the negative control with respect to FEV1, AHR or symptoms. It is concluded that some insecticide aerosols trigger symptoms and falls in lung function in some people with asthma. Furthermore, these aerosols may also increase airway hyperresponsiveness, although the mechanism of this effect has not been determined. The low irritant formulation did not appear to have the same effects.

Association between Der p 1 concentration and peak expiratory flow rate in children with wheeze: a longitudinal analysis

BACKGROUND

House dust mite (HDM) allergen exposure has been well documented as an environmental cause of airway hyperresponsiveness (AHR) and asthma symptoms. The relationship between asthma morbidity and exposure to low concentrations of HDM allergen suggests that there may be no safe exposure threshold to HDM allergen.

OBJECTIVE

We aimed to investigate the associations between Der p 1 in bedding and lung function in 30 children with a history of wheezing in a longitudinal study.

METHODS

After a cross-sectional study of school children, which included histamine challenge for AHR and skin testing for dust mite atopy, we made repeated measurements of HDM allergens in children with a history of wheeze over a 12-month period. These children also kept a daily asthma diary in which they recorded their peak expiratory flow rates (PEFRs). We used a repeated measures model to determine the association between PEFR and HDM allergen concentration.

RESULTS

There was a significant association between PEFRs and HDM allergen concentration (beta-coefficient = -14.17, P = .0024) in children with HDM atopy. An association was not found in children without HDM atopy.

CONCLUSIONS

These findings support the hypothesis that HDM allergens have an adverse effect on the lung function of children with wheeze and highlight the importance of maintaining low dust mite allergen levels throughout the year in the home environment of children sensitized to HDMs.

Perception of airway narrowing in a general population sample

In epidemiological studies, defining asthma as the presence of airway hyperresponsiveness (AHR) plus recent symptoms leaves two groups of subjects whose clinical significance is unclear: those with asymptomatic AHR, and those with symptoms only. The aim of the study was to determine whether subjects with symptoms only differ from the normal and asthmatic groups in the perception of airway obstruction. Six hundred and ninety seven adults completed a questionnaire of symptoms and underwent bronchial challenge with histamine to induce airway obstruction. Recent symptoms included wheeze and morning chest tightness in the last 12 months. AHR was defined as a provoking dose of histamine causing > or = 20% fall in forced expiratory volume in one second (PD20FEV1) <3.9 micromol. At the end of the challenge test, subjects who felt wheezy or tight in the chest marked a value from 0 to 10 on a modified Borg scale, to describe the severity of the sensation. Subjects with asymptomatic AHR did not differ significantly from subjects with AHR plus recent symptoms (current asthma) either in the mean fall in FEV1 or in the median Borg score. In subjects with symptoms only, the mean Borg score was not significantly different from that of the asthmatic subjects, although mean fall in FEV1 differed significantly (p<0.0001). In subjects with symptoms only, chest tightness correlated significantly with the fall in forced vital capacity (FVC) (p= 0.011), but not with the fall in FEV1. Subjects with asymptomatic airways hyperresponsiveness were not poor perceivers of airway narrowing, but may underreport their symptoms. Subjects with symptoms only may have enhanced perception of small changes in lung function, particularly in forced vital capacity.

Inhibition of p53 expression by peptide-conjugated phosphorodiamidate morpholino oligomers sensitizes human cancer cells to chemotherapeutic drugs

The p53 tumor suppressor gene encodes a transcription factor that is commonly mutated in cancer. Tumors arise when premalignant cells are unable to undergo p53-dependent apoptosis, cell cycle arrest or DNA repair. The p53-signaling pathway affects not only tumor development, but also the response of tumors to chemotherapeutic drugs. In this study, we use cell penetrating peptide conjugates of phosphorodiamidate morpholino oligomers (PPMOs) to inhibit p53 expression. We examine the functional properties of endogenous p53 isoforms that are produced upon PPMO-mediated inhibition of p53 translation and splicing, and report that loss of N-terminal or C-terminal sequences interferes with the transcriptional activity of p53. Importantly, we report that PPMO-mediated inhibition of p53 expression sensitizes human cancer cells with wild-type p53 to chemotherapeutic drugs.

Factors that affect normal lung function in white Australian adults

STUDY OBJECTIVE

To classify abnormal lung function in epidemiologic studies, we first calculated "normal" values using data from Australian white adults. We then examined the effects of airway hyperresponsiveness (AHR), respiratory symptoms, current and past asthma, and current smoking on spirometric function.

METHODS

A large random sample of 1,527 adults aged 18 to 73 years was studied. We measured respiratory symptoms and smoking history by questionnaire and AHR by histamine inhalation test.

RESULTS

Data from 729 "normal" subjects (asymptomatic nonsmokers without AHR) were used to obtain regression models for FVC, FEV1, peak expiratory flow rate, and forced expiratory flow between 25% and 75% of FVC. The R2 values were 0.76, 0.74, 0.58, and 0.29, respectively. The presence of AHR reduced FVC by 0.1 L and FEV1 by 0.2 L, on average. Subjects with asthma-related symptoms had a mean reduction in FVC of 0.1 L for both genders and in FEV1 of 0.08 L for women and 0.2 L for men. Current asthma reduced FVC by 0.3 L, on average, and FEV1 by 0.5 L for women and 0.6 L for men. The FEV1 was reduced by 0.002 L per cigarette smoked daily.

CONCLUSION

Recent symptoms, AHR, and current smoking were all important predictors of reduced lung function.

Human papillomavirus exposure and sexual behavior are significant risk factors for Barrett's dysplasia/esophageal adenocarcinoma

Given the comparable strains of high-risk human papillomavirus (HPV) present in a subset of Barrett's dysplasia and esophageal adenocarcinoma as in head and neck squamous cell carcinomas and the anatomical proximity of both lesions, we hypothesized that oral sex may increase the risk of Barrett's dysplasia/esophageal adenocarcinoma. Therefore, we compared the sexual behavior of patients with Barrett's dysplasia/esophageal adenocarcinoma and controls (hospital, reflux, and Barrett's metaplasia) to explore a plausible mechanism of viral transmission to the lower esophagus. A hospital-based case-control study involving 36 Barrett's dysplasia/esophageal adenocarcinoma subjects and 55 controls with known HPV DNA status and markers of transcriptional activity i.e p16INK4A and E6/E7 mRNA of the esophageal epithelium was conducted to evaluate differences in sexual history (if any). Barrett's dysplasia/esophageal adenocarcinoma patients were more likely than controls to be positive for HPV DNA (18 of 36, 50% vs. 6/55, 11%, p for trend <0.0001), be male (P = 0.001) and in a relationship (P = 0.02). Viral genotypes identified were HPV 16 (n = 14), 18 (n = 2), 11 (n = 1) and 6 (n = 1). HPV exposure conferred a significantly higher risk for Barrett's dysplasia/esophageal adenocarcinoma as compared with hospital/reflux/Barrett's metaplasia controls (OR = 6.8, 95% CI: 2.1-23.1, adjusted P = 0.002). On univariate analysis, ≥6 lifetime oral sex partners were significantly associated with dysplastic Barrett's esophagus and adenocarcinoma (OR, 4.0; 95% CI: 1.2-13.7, P = 0.046). After adjustment for confounders, HPV exposure and men with ≥2 lifetime sexual partners were at significant risk for Barrett's dysplasia/esophageal adenocarcinoma. If these initial findings can be confirmed in larger studies, it could lead to effective prevention strategies in combating some of the exponential increase in the incidence of esophageal adenocarcinoma in the West.

The effect of parental smoking on presence of wheez or airway hyper-responsiveness in New South Wales school children

BACKGROUND AND AIMS

To assess accurately the effect of parental smoking on the respiratory health of New South Wales (NSW) school children, we obtained a large data set by pooling data from seven cross-sectional studies conducted in NSW between 1991 and 1993.

METHODS

A random sample of 6394 children age eight to 11 years was studied. Respiratory symptoms, family history of asthma and parental smoking history were measured by questionnaire, atopy by skin prick test and airway hyper-responsiveness (AHR) by histamine inhalation test.

RESULTS

In total, 58.3% of children had at least one parent who smoked; 38.5% were exposed to maternal smoking. After adjusting for potential confounders, such as atopy, parental history of asthma and bronchitis in the first two years, children who were exposed to maternal smoking had a significantly increased risk of recent wheeze but not of AHR (odds ratios 1.33; 95% CI: 1.2-1.5 and 1.00; 95% CI: 0.9-1.2).

CONCLUSIONS

The positive association with wheeze and the lack of an association with AHR suggests that exposure to parental smoking leads to wheezing, but does not increase airway responsiveness.

Effects of compound injection of Pyrola rotundifolia L and Astragalus membranaceus Bge on experimental guinea pigs' gentamicin ototoxicity

In attempting to find drugs effective in preventing and remedying ototoxic injury caused by aminoglycoside antibiotics, we relied on the theory that the induction of ototoxic injury by aminoglycoside antibiotics is related to a decrease of cyclic adenosine monophosphate and RNA content in the cochlea or a dysfunction of the kidney. We selected Pyrola rotundifolia L and Astragalus membranaceus Bge from traditional Chinese herbal medicine, made a compound injection of them, and observed the effect on the pattern of gentamicin ototoxicity in guinea pigs. By electrocochleography and morphology by scanning electron microscopy, the experimental results indicated that the Chinese herbal compound possessed the definite effect of protecting the guinea pig cochlea. The determination of blood urea nitrogen, urinary N-acetyl-D-aminoglucosidase, and urinary protein and observation of renal morphology showed that it also protected the kidney against nephrotoxic nephritis of gentamicin. The conjecture that protection of the kidney by the Chinese herbs may be one of the important factors in preventing ototoxicity supports some explanations of ototoxic mechanisms induced by aminoglycoside antibiotics.

Molecular cloning and expression analysis of a novel BCCP subunit gene from Aleurites moluccana

Aleurites moluccana L. is grown as a roadside tree in southern China and the oil content of its seed is higher than other oil plants, such as Jatropha curcas and Camellia oleifera. A. moluccana is considered a promising energy plant because its seed oil could be used to produce biodiesel and bio-jet fuel. In addition, the bark, leaves, and kernels of A. moluccana have various medical and commercial uses. Here, a novel gene coding the biotin carboxyl carrier protein subunit (BCCP) was cloned from A. moluccana L. using the homology cloning method combined with rapid amplification of cDNA end (RACE) technology. The isolated full-length cDNA sequence (designated AM-accB) was 1188 bp, containing a 795-bp open reading frame coding for 265 amino acids. The deduced amino acid sequence of AM-accB contained a biotinylated domain located between amino acids 190 and 263. A. moluccana BCCP shows high identity at the amino acid level to its homologues in other higher plants, such as Vernicia fordii, J. curcas, and Ricinus communis (86, 77, and 70%, respectively), which all contain conserved domains for ACCase activity. The expression of the AM-accB gene during the middle stage of development and maturation in A. moluccana seeds was higher than that in early and later stages. The expression pattern of the AM-accB gene is very similar to that of the oil accumulation rate.