摘要:

AbstractOne of the factors that may contribute to the exaggerated airway narrowing in asthma is an abnormality of the airway smooth muscle. This abnormality could take the form of an increase in the amount of muscle or an alteration in its pharmacological reactivity. The former could be due to either hypertrophy (an increase in individual muscle cell size) or hyperplasia (an increase in cell number). Changes in pharmacological reactivity that could be relevant to altered airway calibre could result from an increase in contraction or alternatively, a decrease in relaxation. Based on available evidence, the increase in smooth muscle bulk is probably the consequence of both hyperplasia and hypertrophy and several growth factors, inflammatory mediators and cytokines have been implicated. Asthmatic airway tissue is rarely available forin vitropharmacological studies and evidence for enhanced contraction is limited. Recent evidence suggests that an abnormality in beta adrencoceptor function may contribute to impairment of relaxation, but further work needs to be done. Passive sensitization of non‐asthmatic airwaysin vitroprovides a good model for the study of the mechanisms underlying airway hyperresponsiveness, and will be the subject of more intensive study in the futur

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00026.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe prevalences of bronchial asthma in the Asia‐Pacific region range from 0 to 24% and appear to be increasing in some countries. The increased prevalence of asthma may be related to the urbanization of these countries or areas. Risk factors relating to the development of asthma are multiple and complex. These include: Predisposing or genetic factors: (atopy and bronchial hyperresponsiveness; BHR) that increase an individuals susceptibility. Longitutinal studies in children have shown that BHR precedes asthma in some individuals. A gene governing BHR is located near a major locus that regulates serum IgE levels on chromosome 5 q. An additional gene that determines the specificity of the immune response located in the human leukocyte antigen complex (HLA) may govern the specificity of the immune response to common aeroallengens in some individuals. Causal factors: inhaled allergens are the most important causal factors of asthma, which include indoor allergens (domestic mites, animal, cockroach and fungus allergens), domestic mites being the most common potential allergen, and outdoor allergens (pollens from trees, grasses and weeds). Owing to the geographic location and different sensitivity to allergen between races, allergens vary from area to area. Certain drugs, food and food additives are also the cause of asthma attack. Contributing factors: smoking is an important trigger and a serious problem in most Asian Pacific countries. Air pollution in particular sulfur dioxide (SO2), nitrogen dioxide (NO2) and respirating particles are common contributing factors. Very low concentration of SO2(0.5 ppm) can cause bronchospasm in asthmatics. A combination of low concentration of SO2and NO2often encountered in heavy traffic further enhances the airway responsiveness to inhaled allergen. In addition, respiratory virus infection is closely associated to the development of asthma in childhoo

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00027.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractObstructive sleep apnoea (OSA) is a common disorder, and is characterized by repetitive closure of the upper airway during sleep. Upper airway narrowing and sleep‐induced loss of muscle tone are important factors in the development of OSA. Over the last decade there has been a growing recognition that craniofacial abnormalities occur commonly in OSA patients. The more commonly identified abnormalities include mandibular deficiency, an inferiorly placed hyoid bone relative to the mandibular plane, a narrowed posterior air space, a greater flexion of the cranial base, and elongation of the soft palate. It is thought that these abnormalities result. in upper airway narrowing, thereby predisposing to OSA. When the well established role of obesity in the development of OSA is taken into account, a model of OSA emerges in which the degree of craniofacial abnormalities determines the extent of obesity required to produce OSA in a given individual. The recognition of the role of craniofacial abnormalities in the development of OSA has led to a number of treatment strategies aimed at correcting or improving craniofacial structure, thereby preventing upper airway collapse during sleep. These treatments include dental appliances, and various maxillofacial surgical procedures. An improved understanding of the evolution of OSA from childhood to adulthood, in relation to facial development, may lead to a preventative strategy for this disorde

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00028.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractExercise induced asthma is a common complaint and the prevalence appears to be increasing worldwide. Once confined to the research domain of university teaching hospitals, the study of EIA has extended into the school playground, defence force establishments and sports institutions. Standardized protocols have been developed to study EIA in the laboratory and in the field. A surrogate challenge using eucapnic or isocapnic hyperventilation with dry air is becoming popular because it has advantages over exercise, at least for adults. The stimulus that leads the airways to narrow is caused by the inhalation of dry air during hyperventilation and exercise, during which water is evaporated from the airways in order to condition the inspired air. The mechanism whereby the airways narrow is thought to be due to the dehydrating effects of water loss, particularly in relation to its potential to cause the airways to become hyperosmolar. Mast cell mediators such as histamine and the leucotrienes are probably involved in EIA because specific antagonists reduce severity. As a result of the osmotic theory of EIA, studies were carried out to determine whether subjects with EIA were sensitive to the effects of increasing airway osmolarity by inhalation of hyperosmolar aerosols of sodium chloride. A challenge protocol using an aerosol of 4.5% sodium chloride, generated from an ultrasonic nebulizer, has been used to identify persons with asthma and to assess response to drug therapy. There are many similarities between responses to exercise, hyperventilation and hypertonic saline in the physiological and biochemical responses and the responses to drugs. Challenge with hypertonic saline is easier and cheaper to use because expensive equipment and a source of dry air is not required as with exercise or hyperventilation. The ability to obtain a dose‐response curve rather than a single response and the ability to collect inflammatory cells at the same time make challenge with hypertonic saline an attractive technique to study patients suspected of having asthm

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00029.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis review considers the issues involved in measuring the community prevalence of asthma, particularly in the context of international comparisons. We argue that there is no gold standard definition for measuring asthma prevalence, and discuss the currently available methods of case ascertainment. Prevalence studies, if they are to be generalizable, need to involve large sample sizes with high response rates. This necessitates methods that are simple, inexpensive and practicable, but also as sensitive and specific for asthma as possible. We discuss some of the issues that are specific to comparisons of asthma prevalence between diverse populations, and suggest that large surveys using written or video questionnaires of self reported symptoms validated in all of the target populations are the method of choice.

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00030.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe efficacy of mask‐applied continuous positive airway pressure (CPAP) in the treatment of patients with acute severe exacerbations of chronic obstructive pulmonary disease (COPD) was examined. Ten patients with severe exacerbation of COPD who had deteriorated during conventional therapy were treated with face‐mask delivered CPAP (+5 cmH2O; Downs Vital signs Inc., New Jersey, USA) instead of tracheal intubation and mechanical ventilation. The patients that were selected required mental alertness, intact upper airway reflexes, the clinical signs of dynamic hyperinflation and a positive end‐expiratory pressure auto‐(PEEP) manifested as expiratory wheeze and grunting. Nine out of 10 patients responded promptly to mask‐CPAP with less distress, better oxygenation, lower respiratory and pulse rates. There was no significant change in arterial carbon dioxide tension with mask‐CPAP treatment. One patient deteriorated on mask‐CPAP and required intubation and mechanical ventilation. Three patients died (none of these patients died during the acute period of exacerbation). It was concluded that Mask‐CPAP may be an alternative to mechanical ventilation in the treatment of selected patients with severe hypercapnic exacer

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00031.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAutonomic nervous system abnormalities in airway control may contribute to the symptoms of asthma, and even to the pathogenesis of bronchial hyperresponsiveness (BHR). Partial pulmonary sympathetic denervation by means of bilateral upper dorsal thoracoscopic D2–D3sympathicolysis (TS) is an accepted treatment in severe essential hyperhidrosis (EH). The effects of this intervention on BHR are unknown. The objective of this study was to evaluate whether partial pulmonary sympathetic denervation by means of TS has an effect on BHR. Bronchial challenge tests with histamine, enabling the calculation of the provocative dose causing a 20% reduction in FEV1(PD20 His) were performed 1 day before, and 6 weeks and 6 months after TS in 35 patients with severe EH. In nine patients (including three patients with a previous history of asthma) with pre‐operative BHR (defined as PD20 His<2 mg), mean PD20 Hisdid not change significantly at 6 weeks, nor at 6 months after TS (0.62 ± 0.33, 0.71 ± 0.42 and 0.93 ± 0.65 mg, respectively) although there was a non‐significant trend towards an increase in PD20 Hisat 6 months. Three of the 26 patients (12%) without pre‐operative BHR became hyperresponsive after TS, whereas 1 of the 9 patients with pre‐operative BHR lost hyperresponsiveness. No patient developed asthma symptoms after TS. Upper dorsal thoracoscopic D2–D3sympathicolysis performed for the treatment of EH has no significant effects on mean PD20 Hisand individual loss (11%) or development (12%) of BHR occurs only in a minori

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00032.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractExercise‐induced asthma (EIA) is a common symptom among young asthmatics. The hypothesis that asymptomatic day‐to‐day wide fluctuations in lung function and asymptomatic persistent airflow obstruction are risk factors for the development of EIA was studied. The study population was a cohort of known asthmatic children aged 9–14 years attending a residential asthma camp. The method involved the observation of baseline expiratory peak flow recordings (PEFR) for 5 days while the children were receiving their usual maintenance therapy. The method also included the determination of FEV1pre‐ and post‐ 15 min of continuous aerobic exercise. Exercise‐induced asthma was expressed as the Lability index (LI). The findings were that LI was significantly correlated (P<0.01) with the mean PEFR as a per cent of each child's predicted PEFR. The lability index also correlated (P<0.01) with the degree of day‐to‐day variability in PEFR expressed as the coefficient of variance (CV). It is concluded that there is a significant correlation between baseline asthma control and the development of EIA. In addition to recommending pre‐exercise prophylaxis, practitioners should investigate overall asthma control in chi

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00033.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe objective of this study was to present clinical and radiological data of eight women with histologically proven lymphangioleiomyomatosis (LAM) diagnosed between 1984 and 1994, and to suggest a diagnostic strategy when LAM is suspected. A review of case reports, including results of biopsies, lung function and radiological procedures was undertaken. The mean age of the women at start of symptoms was 36 years, and the mean age at time of diagnosis 42 years. The most frequent presenting complaint was dyspnea, either in conjunction with pneumothorax (3), chylothorax (2) or on exertion (2). All patients had airflow limitation and markedly reduced gas transfer. Five patients had 16 episodes of pneumothorax. In seven patients multiple cysts were observed on the surface of the lung during thoracotomy while computerized tomography (CT) scans revealed numerous cysts evenly distributed throughout the lung parenchyma. The procedures that confirmed the diagnosis included transbronchial lung biopsy (4), open lung biopsy (2), thoracoscopy (1), thoracotomy (3) and autopsy (1). Three specimens had to be revised before the histological diagnosis was confirmed. It was concluded that the important clues to a diagnosis of LAM are recurrent episodes of pneumothoraces in fertile women, progressive air‐flow limitation, markedly reduced gas transfer and characteristic findings on thoracic CT scans. A specific request to the pathologist to stain lung tissue specimens for smooth muscle cells is mandator

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00034.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractPulmonary lymphangioleiomyomatosis (PLAM) is rare progressive, fatal interstitial lung disease, considered to be sex hormones related. We report a follow‐up, after 19 years, in a patient with PLAM without intervention. Despite excessive oestrogen production during four pregnancies there was only mild deterioration of her respiratory disease. Patients with good functional reserve should be followed‐up closely before deciding on hormonal ablative treatm

ISSN:1323-7799    

DOI:10.1111/j.1440-1843.1996.tb00035.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY