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Biomedical subjects

M J Abramson

Publications and source records attributed to M J Abramson.

At least 55 records · Page 3Linked to original sources
PubMed1997

Absence of genetic linkage of chromosome 5q31 with asthma and atopy in the general population.

BACKGROUND: Clinical asthma is associated with increased serum total immunoglobulin E (IgE), atopy (skin prick test positivity to common aeroallergens), and bronchial hyperreactivity (BHR) to non-specific stimuli (positive methacholine challenge test). A region on chromosome 5q31-33 has been linked with increased total serum IgE and BHR. A study of the genetic linkage of this region with clinical asthma and atopy was therefore undertaken. METHODS: A polymorphic microsatellite marker in chromosome 5q31 (D5S399) was studied in 119 sibling pairs recruited from the general population who shared asthma, atopy, and/or BHR. Based on our population distribution of 13 different alleles, it was expected that by chance alone sibling pairs would share on average 1.24 alleles and that a significant excess would indicate genetic linkage. RESULTS: No evidence of linkage was found in 45 siblings concordant for asthma (shared alleles = 1.09, p = 0.95), in 103 sibling pairs with atopy (shared alleles = 1.18, p = 0.82), in 51 sibling pairs with BHR (shared alleles = 1.22, p = 0.62), or in 68 sibling pairs who shared atopy in the absence of BHR (shared alleles = 1.22, p = 0.61). A slight non-significant excess of shared alleles (1.44, p = 0.11) was observed in siblings who shared BHR without atopy. CONCLUSIONS: No evidence of genetic linkage of chromosome 5q31 with either clinical asthma or atopy was therefore detected in the population studied. Linkage between chromosome 5q and BHR needs further investigation.

Adult↗
PubMed1996

Asthma management in eastern Australia, 1990 and 1993.

OBJECTIVE: To compare the prevalence and management of asthma before and after institution of the National Asthma Campaign. DESIGN: Repeat population-based cross-sectional analytic surveys. SETTING: Eastern Australia (Sydney, Brisbane, Melbourne, and the Hunter Valley, New South Wales) in September 1990 and 1993. SUBJECTS: Primary school children and their parents from 33 schools (8746 children) in 1990 and 40 schools (10 106 children) in 1993. OUTCOME MEASURES: Frequency of respiratory symptoms; diagnoses of asthma; medications; lung function measurements; possession of a peak flow meter and a written action plan. RESULTS: Age and sex distribution of the subjects and the reported prevalence of asthma were similar in 1990 and 1993. The frequency of reported episodes of wheezing and troublesome cough increased significantly in children between 1990 and 1993. Asthma management improved in accordance with current recommendations, with significantly decreased use of regular inhaled bronchodilator medication in children and increased use of preventive medication, monitoring of lung function by doctors and use of peak flow meters and written action plans in both children and adults. CONCLUSION: There is evidence that the National Asthma Campaign may have contributed to increased awareness and improved management of asthma in children and adults in eastern Australia.

Adult↗
PubMed1996

Assessment of the severity of asthma in a family practice.

The objective of this study was to evaluate clinical history and self-perception of severity as predictors of asthma severity. A short-term longitudinal study was conducted in a family practice in Melbourne, Australia, utilizing peak flow monitoring, medication diary, and self-administered asthma severity questionnaire. Seventy-two asthmatic subjects with a positive bronchodilator or exercise test, aged between 6 and 79 years, were studied. Symptom and treatment items were correlated with peak flow variability and minimal peak expiratory flow rate (PEFR). An asthma severity scale was generated using the partial credit version of Item Response Theory and the participants' severity scores were validated against lung function tests and medication usage. Quantitative modeling procedures were used to investigate the interrelationships of factors associated with peak flow variability. Severity scores demonstrated significant relationships with peak flow variability (partial r = 0.34) and treatment items. Self-perceived severity of asthma in the preceding 2 weeks showed significant association with peak flow variability (partial rho = 0.46) and minimal PEFR (rho = -0.41). The severity module of the Monash Respiratory Questionnaire is a valid and reliable instrument. The most important symptoms appear to be the frequency of use of bronchodilator and frequency of nocturnal attacks. A carefully structured clinical history in conjunction with the peak flow criteria of variability and minimal peak flow rate would be appropriate in the evaluation of asthma severity. Patients' self-perception of the severity of their asthma needs further evaluation.

Adolescent↗
PubMed1995

Are non-allergenic environmental factors important in asthma?

OBJECTIVE: To review the roles of viral respiratory tract infections, environmental tobacco smoke and air pollution in asthma. DATA SOURCES: MEDLINE (1992-1995) searches were conducted for publications on asthma, environmental tobacco smoke, ozone, nitrogen dioxide and particulates. STUDY SELECTION: Representative original experimental and epidemiological studies and reviews of viral infections in asthma. DATA SYNTHESIS: Respiratory virus infections are the most common and important trigger of asthma attacks in children and probably also in adults. Their role in promoting development of asthma is not so clear. Exposure to environmental tobacco smoke is almost certainly responsible for some cases of childhood asthma, and can also trigger symptoms of bronchoconstriction in adults with asthma. Exposure to ozone or nitrogen dioxide is associated with symptoms, impaired lung function, bronchial hyperresponsiveness and hospital presentations for asthma. These pollutants may also act as cofactors in the development of allergen-specific bronchial hyperresponsiveness. CONCLUSIONS: Research on preventing upper respiratory viral infections may reduce asthma morbidity. The move to non-smoking workplaces is welcome, but new interventions are needed to prevent young women taking up smoking and subsequently exposing their children. The ambient air quality guideline for ozone should be revised and a health-based guideline for respirable particulates introduced.

Air Pollution↗
PubMed1995

Linkage of high-affinity IgE receptor gene with bronchial hyperreactivity, even in absence of atopy.

Asthma is a manifestation of bronchial hyperreactivity (BHR) and forms part of the spectrum of atopic disease. Some pedigree studies of atopy have suggested linkage with the high-affinity IgE receptor (Fc epsilon RI beta) gene on chromosome 11q13, but others find no linkage. The molecular genetics of asthma and BHR have not been studied in the general population. We examined the genetic linkage of the Fc epsilon RI beta gene with clinical asthma and the underlying phenotypes of BHR (to methacholine) and atopy (defined by skinprick testing) in 123 affected sibling-pairs recruited from the general population. We found evidence of significant linkage of a highly polymorphic microsatellite marker in the fifth intron of the Fc epsilon RI beta gene to a diagnosis of asthma (18.0% excess of shared alleles, p = 0.002) and to BHR (21.7% excess of shared alleles, p = 0.001). Significant linkage was also observed in siblings sharing BHR when those with atopy were excluded (32.8% excess of shared alleles, p = 0.004). Atopy in the absence of BHR did not show significant linkage to the Fc epsilon RI beta gene (7.2% excess of shared alleles, p = 0.124). These findings suggest that mutations in the Fc epsilon RI beta gene or a closely linked gene influence the BHR underlying asthma, even in the absence of atopy.

Adult↗
PubMed1995

Morbidity, medication and trigger factors in a community sample of adults with asthma.

OBJECTIVES: To determine asthma morbidity, use of medications and trigger factors for asthma attacks in an adult community sample. METHODS: Follow-up questionnaires were sent to respondents indicating a history of asthma or any respiratory symptom on a screening questionnaire. A new scale to measure asthma severity was developed. RESULTS: Questionnaires were returned by 74% (589/795). Respondents with diagnosed asthma had more frequent symptoms and more disruption to lifestyle than those with non-specific respiratory symptoms. Inhaled beta-agonist and oral theophylline preparations were used by 61% and 16% of asthmatics, respectively. Preventive medications such as inhaled corticosteroids and cromoglycate were used daily by only 15% and 4%, respectively. The most frequently reported trigger factors were viral upper respiratory tract infections, cigarette smoke, house dust, smog and other non-specific irritants. Twenty per cent of asthmatics reported occupational exacerbation of symptoms. CONCLUSIONS: There is substantial morbidity from asthma in Victorian adults, which could be reduced by greater use of preventive medications, avoidance of trigger factors, peak flow monitoring and action plans. The asthma severity scale proved to be reliable and valid.

Administration, Inhalation↗
PubMed1995

Assessment of the future impact on health of a proposed freeway development.

This paper estimates the effect on health of traffic injury and air and noise pollution from a proposed inner-suburban freeway in Melbourne. We estimated levels of these health problems for the year 2001 using traffic flow projections for the presence and absence of the freeway. For noise and air pollution, it was necessary to use pollutant levels as proxies for levels of associated diseases and health states. In 2001, there will be an increase in all traffic movements in the study area but a decrease of 100,000 vehicle-kilometers per day on major roads, excluding the bypass. This is associated with a projected reduction in the study area of about 100 to 110 injuries of all types. The major air pollution problems associated with motor vehicle emissions are ozone and respirable particulates; sulphur dioxide, nitrogen dioxide and carbon monoxide are unlikely to pose a health hazard. Levels of respirable particulates, lead and polycylic aromatic hydrocarbons are generally low. There should be no detectable increase in average or maximum noise levels adjacent to the freeway if attenuation measures are employed. A reduction in average and maximum noise levels should occur on some main roads in the affected area. The effects of the freeway on the area should be favourable to health, with reduction in traffic injury and noise-related health problems outweighing any risk of a small deterioration in respiratory health associated with atmospheric pollution.

Accidents, Traffic↗
PubMed1995

Is allergen immunotherapy effective in asthma? A meta-analysis of randomized controlled trials.

A meta-analysis of clinical trials of allergen immunotherapy was undertaken to assess the efficacy of this controversial form of therapy in asthma. A computerized bibliographic search revealed 20 randomized placebo controlled double-blind trials of allergen immunotherapy for asthma. The results extracted included asthmatic symptoms, medication requirements, lung function, and bronchial hyperreactivity (BHR). Categorical outcomes were expressed as odds ratios and continuous outcomes as effect sizes. The combined odds of symptomatic improvement from immunotherapy with any allergen were 3.2 (95% CI 2.2 to 4.9). The odds for reduction in medication after mite immunotherapy were 4.2 (95% CI 2.2 to 7.9). The combined odds for reduction in BHR were 6.8 (95% CI 3.8 to 12.0). The mean effect size for any allergen immunotherapy on all continuous outcomes was 0.71 (95% CI 0.43 to 1.00), which would correspond to a mean 7.1% predicted improvement in FEV1 from immunotherapy. Although the benefits of allergen immunotherapy could be overestimated because of unpublished negative studies, an additional 33 such studies would be necessary to overturn these results. Allergen immunotherapy is a treatment option in highly selected patients with extrinsic ("allergic") asthma.

Asthma↗
PubMed1994

Adequacy of control of asthma in a general practice. Is maximum peak expiratory flow rate a valid index of asthma severity?

OBJECTIVES: To evaluate the adequacy of control of asthma in patients attending a general practice; and to examine the validity of peak expiratory flow rate (PEFR) as an index of asthma severity in the context of general practice. DESIGN: Short-term cohort study using indices derived from two weeks of peak flow monitoring to evaluate asthma control. PARTICIPANTS: Known and newly diagnosed asthmatics aged six years or more who presented during the study period for any reason. They were enrolled if baseline forced expiratory volume in one second (FEV1) increased by 10% or more after the administration of nebulised salbutamol. Children under the age of 12 years with no initial response to bronchodilator were included if an exercise test performed on another day was positive. OUTCOME MEASURES: Peak flow criteria for "mild asthma" in the Asthma Management Plan, 1989 (Med J Aust 1989; 151: 650-653) were used as the initial definition of "adequate control". The definition of "adequate control" was modified to variability less than 20% and a minimum PEFR of 50% or more of mean predicted value. RESULTS: There was no association between variability and maximum PEFR, but variability was strongly correlated with minimum PEFR (R = -0.60; P < 0.0005). Asthma was adequately controlled in 68% of the participants. CONCLUSION: Current guidelines with respect to the peak flow indices used in the classification of the severity of asthma need to be re-evaluated and probably changed for application in general practice.

Asthma↗
PubMed1992

Asthma morbidity in Australia: an epidemiological study.

OBJECTIVE: To examine the prevalence and management of asthma in adults and children in a population sample in eastern Australia. SETTING: A random sample of children from 33 primary schools in Sydney, Melbourne, Brisbane, and the Upper Hunter Valley (New South Wales), and their parents. DESIGN: A cross-sectional analytic survey of 8753 primary school children aged between 5 and 12 years, and their parents (n = 13,945 adults). Asthma prevalence and management practices were determined by parental responses to a questionnaire, and spirometry was performed in children with "probable asthma". RESULTS: Of 8753 children whose parents responded, the prevalence of current wheeze was 19.5% and diagnosed asthma was 17.1%. Of the children with "probable asthma", 30% had their lung function measured in the previous year, and 6% possessed both a peak flow meter and an action plan for their asthma. Undertreatment was likely, as preventive asthma medications (inhaled corticosteroids or sodium cromoglycate) were used regularly by only 25.5% of these children and by 44.3% of children who had asthma symptoms more than twice per week. Children with the diagnosis of asthma reported higher rates of preventive medication use and ventilatory function measurement than children with frequent symptoms without the diagnosis. In the 13,945 adults, the reported prevalence of asthma was 7%, of whom 39% were using preventive medications, 34% had their ventilatory function assessed in the previous year, and 7% had both a peak flow meter and an asthma action plan. CONCLUSIONS: The study illustrated the gap between the current level of asthma management in the community and the standards set by the Thoracic Society of Australia and New Zealand. Undertreatment and suboptimal management of asthma remain important problems in Australia.

Administration, Inhalation↗
PubMed1991

Lung function abnormalities and decline of spirometry in scleroderma: an overrated danger?

To document the prevalence and progression of pulmonary involvement in scleroderma (systemic sclerosis including the CREST syndrome), the clinical notes and lung function records of 113 cases were reviewed. Lung function was normal in 39 cases, isolated impairment of DLCO was found in 38 patients, a restrictive defect was present in 27 cases and there was evidence of airflow obstruction in 9 cases. The median duration of symptoms was 10 years. Dyspnoea and an interstitial pattern on chest X-ray were associated with impaired lung function. Death during the period of review was significantly related to initial impairment of the DLCO. Sixty-six patients (53 women and 13 men) underwent repeat spirometry at least 1 year after initial testing. The rates of change in VC and FEV1 were no more rapid than would be expected for normal subjects. There was no significant difference in rates of change between men and women or between dyspnoeic patients and those who were asymptomatic. The extent of skin involvement and the presence of interstitial fibrosis on chest X-ray were unrelated to the rate of loss of lung function. It is concluded that most scleroderma patients in this study had abnormal lung function when first tested, but overall significant worsening of spirometry was not found.

Adolescent↗
PubMed1991

Evaluation of a new asthma questionnaire.

The new International Union Against Tuberculosis (IUAT) bronchial symptoms questionnaire was completed by 827 subjects participating in a prospective study of respiratory symptoms and lung function in aluminum smelter workers. A modified Medical Research Council (MRC) questionnaire was also administered. Bronchial reactivity (BR) was measured in 809 subjects by methacholine challenge using a rapid method. Factor analysis demonstrated sensible clustering of responses to items unique to the new questionnaire such as nocturnal, spontaneous, and postexertional dyspnea, dust-induced dyspnea and tightness, and breathing difficulty. Responses to IUAT questions concerning past asthma, wheeze, chest tightness, morning cough and sputum, and asthma medication agreed well with corresponding items from the MRC questionnaire. Questions concerning asthma, medication, dust-induced, nocturnal, and spontaneous dyspnea, chest tightness, wheeze, nocturnal cough, postexertional dyspnea and breathing difficulty also had high validity against the criterion of concurrently measured bronchial reactivity. It is concluded that the IUAT questionnaire is a valid asthma questionnaire.

Asthma↗
PubMed1990

Analysis of bronchial reactivity in epidemiological studies.

The measurement of bronchial reactivity in epidemiological studies has the advantage of quantifying an objective physiological feature of asthma. Bronchial reactivity was developed in a clinical setting and has been conventionally expressed as the dose of agonist producing a 20% fall in FEV1 (PD20). As PD20 can be estimated for less than 20% of subjects in general community surveys with the doses of agonist that are usually given, data from most subjects must be censored. Thus PD20 alone is a poor index of bronchial reactivity for epidemiological studies. Data from 809 aluminium smelter workers were used to evaluate alternative methods of analysing bronchial reactivity. Dose-response relationships were analysed by four methods: (1) PD20 by the conventional method of interpolating the dose on a logarithmic scale between the last two measurements of FEV1; (2) PD20 (with allowance for extrapolation), estimated by fitting an exponential curve to the dose-response data; (3) the linear regression slope between dose and FEV1 when significant; (4) the dose-response slope obtained in all subjects as the % change in FEV1 from baseline in response to total dose. When each of these measures was related to symptoms, diagnosis, and treatment of asthma, all differentiated between "asthmatic" and "non-asthmatic" subjects. The dose-response slope (method 4) had the advantages of simplicity and no censored data, and was shown to be clinically relevant. It is suggested that the dose-response slope should be used for the analysis of bronchial reactivity in epidemiological studies.

Airway Resistance↗
PubMed1989

Does aluminum smelting cause lung disease?

The evidence concerning a relationship between work in the aluminum industry and lung disease has been reviewed using epidemiologic criteria. Adequate data on environmental exposure are rarely presented. Case series on aluminum potroom workers over the past 50 years have identified an asthmalike syndrome that appears to be due to an irritant rather than an allergic mechanism. These studies have been supported by evidence of within shift variability of measures of lung function. However, to date, there is inadequate evidence to resolve the question of whether potroom exposure initiates asthma or merely precipitates asthmalike symptoms in a predisposed individual. Cross-sectional studies have demonstrated evidence of reduced lung function, consistent with chronic airflow limitation. In exposed aluminum smelter workers compared to unexposed control subjects. Cigarette smoking, the major potential confounding variable, has been measured and accounted for in multivariate analyses. To date, evidence is lacking from longitudinal studies about the development of disabling chronic obstructive lung disease. Exposure to coal tar pitch volatiles in the production and consumption of anodes has biologic plausibility for an association of lung cancer with work in an aluminum smelter. Although retrospective mortality studies have failed to account for the probable high prevalence of smoking in blue collar workers, the relative risk of lung cancer is very low if present at all. Pulmonary fibrosis has not been shown to be a significant problem in aluminum smelter workers. Future research in the aluminum industry needs to concentrate on longitudinal studies, preferably with an inception cohort for the investigation of potroom asthma.

Aluminum↗
PubMed1987

The role of bronchoalveolar lavage in the diagnosis of suspected opportunistic pneumonia.

We report 50 immunocompromised patients with pulmonary infiltrates who underwent fibreoptic bronchoscopy, including bronchoalveolar lavage, on 56 occasions. The underlying diseases were mostly lymphoma, leukemia, other malignancies and renal failure. The commonest immunodeficiency factors were chemotherapy, steroids and neutropenia. A positive diagnosis could be made from analysis of the bronchoalveolar lavage on 59% (33/56) occasions. This was a comparable yield to transbronchial lung biopsy 57% (16/27), and superior to proximal airways wash 24% (13/55), or bronchial brushings 29% (10/34). Open lung biopsy added additional diagnostic information in three of the four cases in which it was performed. The most common final diagnoses were bacterial, viral or Pneumocystis carinii pneumonia and recurrent malignancy. We conclude that bronchoalveolar lavage is a safe procedure with a high diagnostic yield in the immunocompromised host with suspected opportunistic pneumonia.

Bacterial Infections↗