[New characteristics of COVID-19 caused by the Omicron variant in Guangzhou]

We investigated the types of novel coronavirus strains present during the Omicron epidemic from late 2022 to early 2023, COVID-19 co-infections with other pathogens, and clinical characteristics of patients with novel coronavirus infections. Adult patients hospitalized due to SARS CoV-2 infection in six hospitals in Guangzhou city were included in the study from November 2022 to February 2023. Clinical information was collected and analyzed, and bronchoalveolar lavage fluid was obtained for pathogen detection using a variety of techniques, including standard methods and mNGS, tNGS. The results showed that the main strain circulating in Guangzhou was Omicron BA.5.2, and the overall detection rate of potentially pathogenic pathogens combined with Omicron COVID-19 infection was 49.8%. In patients with severe COVID-19 infection, special attention should be paid to aspergillosis and combined Mycobacterium tuberculosis infection. In additon, Omicron strain infection could cause viral sepsis, which led to a worse prognosis for COVID-19 patients. Diabetic patients with SARS-CoV-2 infection did not benefit from glucocorticoid treatment, and caution was necessary when using glucocorticoids. These findings highlighted some new features of severe Omicron coronavirus infection that should be noted.

Proteobacteria community compositions correlate with bronchiectasis severity

BACKGROUND

Proteobacteria contributes to airway inflammation and poor clinical outcomes in bronchiectasis.

OBJECTIVE

To compare sputum Proteobacteria compositions according to bronchiectasis severity.

METHODS

Sputum samples collected from 106 patients with stable bronchiectasis and 17 healthy subjects were split for 16srRNA sequencing and biomarker measurement. Pairwise changes in Proteobacteria compositions among 22 of 106 patients during stability, exacerbations and convalescence were compared. Patients were stratified based on the Bronchiectasis Severity Index (BSI).

RESULTS

Respectively 44, 34 and 28 patients had mild, moderate and severe bronchiectasis. A higher BSI was associated with a greater relative abundance of Proteobacteria and lower Shannon-Wiener diversity index, Simpson diversity index and bacterial richness. Similar findings applied at genera levels. Proteobacteria and Pseudomonas were the major phylum and genus, respectively, contributing to community similarity in moderate-to-severe bronchiectasis. These significant correlations were not observed in those in whom Pseudomonas aeruginosa was not isolated. Proteobacteria abundance correlated with lung function, but not sputum inflammatory biomarkers in severe bronchiectasis. Proteobacteria compositions in severe bronchiectasis were less likely to change significantly during exacerbations and convalescence.

CONCLUSION

Proteobacteria compositions (particularly culturable Pseudomonas abundance) were correlated with bronchiectasis severity. Proteobacteria and Pseudomonas contributed most to community similarity in patients with a higher BSI, indicating microbial targets for interventions in severe bronchiectasis.

[Lower airway abnormalities in patients with allergic rhinitis]

Objective: To investigate the characteristics of lower airway abnormalities in allergic rhinitis(AR) patients without asthma. Methods: Between June 2008 and December 2012, 377 consecutive AR patients and 264 healthy subjects were recruited. All subjects underwent meticulous history taking, nasal examination, allergen skin prick test, blood routine test, serum total immunoglobin E assay, induced sputum cell count and differentials, measurement of fractional exhaled nitric oxide (FeNO) and bronchial challenge test. Results: The positive rates in AR patients was 12.2%(46/377) for bronchial provocation test, 49.2%(185/377) for FeNO, 39.0%(147/377) for sputum eosinophilia, 15.6%(40/377) for peripheral blood eosinophilia and 55.4%(209/377) for increased serum total IgE levels, which were consistently and statistically higher than those of healthy controls(P<0.01). The levels of FeNO [35.0 (21.8, 65.9)ppb], induced sputum eosinophil percentage [2.0 (0.0, 7.5)%], peripheral blood eosinophil percentage [2.9 (1.8, 4.5)%] and serum total IgE [178.4 (63.1, 384.0)kU/L] in AR patients were also higher(P<0.01). Compared with healthy controls, patients with AR demonstrated lower levels of FEV₁/FVC%, MMEFpred%, MEF₇₅ pred%, MEF₂₅pred% (all P<0.05). Statistical analysis showed that FeNO, ratio of induced sputum eosinophil percentage and peripheral blood eosinophil percentage had significant correlations with each other(P<0.01), the r value being 0.247, 0.235, 0.355 respectively. Conclusion: AR without asthma is characterized by lower airway inflammation, small airway impairment and bronchial hyperreactivity, features similar to those of asthma.

[Hemoptysis in adults with bronchiectasis: correlation with disease severity and exacerbation risk]

Objective: To investigate the association between hemoptysis and disease severity and risks of acute exacerbations in patients with bronchiectasis. Methods: Between September 2012 and January 2014, we recruited 148 patients (56 males, 92 females, mean age: 44.6 years) with clinically stable bronchiectasis, who were classified into hemoptysis group (36 males, 70 females, mean age: 45.6 years) and non-hemoptysis group (20 males, 22 females, mean age: 41.8 years). We inquired the past history, and evaluated chest imaging characteristics, lung function, cough sensitivity assessed using capsaicin cough challenge tests, and airway inflammation. We also performed a 1-year follow-up to evaluate whether patients with hemoptysis would have greater risk of having acute exacerbations. Results: In the hemoptysis group, median 24-hour sputum volume was 20.0 ml, median Bronchiectasis Severity Index (BSI) was 7.0, median bronchiectatic lobes was 4.0, median chest CT score was 7.0, the geometric mean for eliciting 5 coughs following capsaicin cough sensitivity (C5) was 77 μmol/L, 67 cases (63%) had cystic bronchiectasis and 52 cases (49%) had pulmonary cavity shown on chest CT, and 35 cases (33%) had Pseudomonas aeruginosa colonization. In the non-hemoptysis group, median 24-hour sputum volume was 5.0 ml, median BSI was 4.0, median bronchiectatic lobes was 3.0, median chest CT score was 5.0, 15 cases (36%) had cystic bronchiectasis and 10 cases (24%) had pulmonary cavity, the geometric mean for C5 was 212 μmol/L, and 4 cases (10%) had Pseudomonas aeruginosa colonization. All the above parameters differed significantly between the hemoptysis and the non-hemoptysis group (P<0.05). In the hemoptysis group, 29 patients with pulmonary cavity (27%) had reported the use of intravenous antibiotics, and 44 cases (42%) had at least one hospitalization within the previous 2 years. In the non-hemoptysis group, 8 cases (19.0%) had reported the use of intravenous antibiotics, and 8 cases (19.0%) reported hospitalization within 2 years. A prior history of hemoptysis was associated with a greater risk of experiencing bronchiectasis exacerbations during follow-up, after adjusting for age, sex, smoking status and BSI (62 cases in the hemoptysis group, 18 cases in the non-hemoptysis group, χ(2)=16.06, P=0.03). In a multivariate model, cystic bronchiectasis was the sole risk factor for hemoptysis; 67 cases which accounted for 63% of patients in the hemoptysis group and 15 cases which accounted for 36% of patients in the non-hemoptysis group, odds ratio: 2.84, 95% confidence interval: 1.00-8.14, P=0.05 . Conclusions: In this study, 72% of bronchiectasis patients had experienced hemoptysis, which was associated with the severity of bronchiectasis. Patients with a prior history of hemoptysis had a greater risk of acute exacerbations during follow-up than those without.

Sputum bacteriology in steady-state bronchiectasis in Guangzhou, China

BACKGROUND

The impact of potentially pathogenic micro-organisms (PPMs) on Chinese patients with steady-state bronchiectasis is unknown.

METHODS

Peripheral blood and sputum were sampled to determine inflammatory markers and sputum bacterial density. Spirometry and diffusing capacity were measured. Quality of life was assessed using the St George's Respiratory Questionnaire.

RESULTS

Of 144 patients with steady-state bronchiectasis, Pseudomonas aeruginosa was isolated in 44 cases (30.6%). Compared with other PPMs, P. aeruginosa had a more pronounced influence on airway inflammation and spirometry, but not on systemic inflammation or quality of life. The impact of PPMs other than P. aeruginosa on clinical indices was similar. Bacterial density was not correlated with most clinical parameters. Factors associated with PPM isolation included bronchiectasis symptoms for ⩾ 10 years (OR 2.13) and ⩾ 4 bronchiectatic lobes (OR 2.82). Having ⩾ 4 exacerbations within 2 years (OR 2.18) and cystic bronchiectasis (OR 2.23) was associated with the colonisation of PPMs, i.e., isolating an identical PPM on at least two occasions within 1 year.

CONCLUSION

In patients with steady-state bronchiectasis in Guangzhou, P. aeruginosa is the most common organism causing heightened airway inflammation and poor lung function. PPM isolation or colonisation should be suspected in case of longer duration of symptoms, multilobar bronchiectasis, frequent exacerbation and cystic bronchiectasis.

Validation of the Mandarin Chinese version of the Leicester Cough Questionnaire in bronchiectasis

BACKGROUND

The Leicester Cough Questionnaire (LCQ) has been validated for assessing cough-specific health status in bronchiectasis. We translated the LCQ into Mandarin Chinese and investigated its validity, reliability and responsiveness.

METHODS

The LCQ was translated into Mandarin Chinese using the forward-backward translation procedure. A total of 144 out-patients completed the Mandarin Chinese version of the LCQ (LCQ-MC), the Hospital Anxiety and Depression Scale (HADS) and the St George's Respiratory Questionnaire. Reassessments were performed during exacerbations and at 6 months. Concurrent validation, internal consistency, repeatability and responsiveness were determined.

RESULTS

Minor cultural adaptations were made to the wording of LCQ-MC. No other difficulties were found during the translation process, with all items easily adapted to acceptable Mandarin Chinese. The questionnaire was not changed in terms of content layout and the order of the questions. In cognitive debriefing interviews, participants reported that the questionnaire was acceptable, relevant, comprehensive and easy to complete. The LCQ-MC showed good concurrent validity, internal consistency and test-retest reliability. Responsiveness was shown by significant changes in LCQ-MC scores between steady state, the first exacerbation and following 2-week antibiotic treatment (both interval changes, P < 0.01) CONCLUSION: The LCQ-MC is a valid, reliable and responsive instrument for determining cough-specific health status in Chinese bronchiectasis patients.

Development and validation of a chronic obstructive pulmonary disease screening questionnaire in China

OBJECTIVE

To develop a brief, reliable screening questionnaire for chronic obstructive pulmonary disease (COPD) for use in primary care settings.

METHODS

We developed a COPD Screening Questionnaire (COPD-SQ) using data collected from 19,800 subjects aged ≥40 years obtained from an epidemiological study of COPD in China in 2002 (Phase I). A stepwise logistic regression method was adopted for item reduction and scoring. We then assessed the COPD-SQ through a cross-sectional study (Phase II) among 3231 subjects aged ≥40 years.

RESULTS

The final COPD-SQ consisted of seven items: age, smoking pack-years, body mass index, cough, dyspnoea, family history of respiratory diseases and exposure to biomass smoke from cooking. Using the questionnaire to screen for COPD in Phase II, we obtained high classification accuracy with an area under the curve of 0.812 (95%CI 0.786-0.838). The sensitivity, specificity and correct classification rates for COPD diagnosis were respectively 60.6%, 85.2% and 82.7% at a cut-off score of 16.

CONCLUSIONS

The COPD-SQ can be used in first-level screening for COPD.

Cough reflex sensitivity is increased in guinea pigs with parainfluenza virus infection

The purpose of this study was to investigate for the change in cough reflex sensitivity (CRS) caused by parainfluenza virus type 3 (PIV3) infection. Guinea pigs were randomized into a vehicle control, an asthma control, or 1 of 4 PIV3-inoculated groups (referred to as postinfection day [PID] 6, 12, 28, and 42 groups). Evidence of viral protein and nucleic acid within the lung confirmed successful PIV3 infection. Plethysmography was used to assess CRS and airway reaction and airway inflammation was assessed via bronchoalveolar lavage fluid cytology and lung histopathology. Compared with the vehicle control group, CRS was significantly increased in all PID groups (P <.05) in concert with an obvious airway hyperresponsiveness in the PID 6 group. Though a small increase in CRS in the asthma control group was noted, it was not significant compared to the vehicle control group. Total cell counts from the bronchoalveolar lavage fluid of all PIV3-inoculated groups increased markedly and the number of lymphocytes was significantly increased in the PID 6 and PID 12 groups. The lung pathology of PIV3-inoculated animals showed airway inflammation without pneumonia in the acute infectious phase. The temporal and spatial variation of CRS may be the essential mechanism of cough caused by PIV3.

How well do questionnaires perform compared with physical examination in detecting flexural eczema? Findings from the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two

BACKGROUND

Questionnaires are widely used in epidemiological studies to measure eczema symptom prevalence, but there are concerns regarding their accuracy if used as a diagnostic tool.

OBJECTIVES

To compare the performance of a validated eczema symptom questionnaire and a standardized skin examination protocol employed in the second phase of the International Study of Asthma and Allergies in Childhood (ISAAC).

METHODS

A total of 30,358 schoolchildren aged 8-12 years from 18 countries were examined for flexural eczema. Parents also completed an eczema symptom questionnaire. We compared prevalence estimates at the population level based on the questionnaire vs. physical examination. We also compared the skin examination and the ISAAC questionnaire in making a diagnosis of flexural eczema.

RESULTS

The point prevalences for flexural eczema at centre level based on a single examination were lower than the questionnaire-based 12-month period prevalences (mean centre prevalence 3.9% vs. 9.4%). Correlation between prevalences of both outcome measures was high (r = 0.77, P < 0.001). At the individual level, questionnaire-derived symptoms of 'persistent flexural eczema in the past 12 months' missed < 10% of cases of flexural eczema detected on physical examination. However, between 33% and 100% of questionnaire-based symptoms of 'persistent flexural eczema in the past 12 months' were not confirmed on examination.

CONCLUSIONS

ISAAC questionnaire-derived symptom prevalences are sufficiently precise for comparisons between populations. Where diagnostic precision at the individual level is important, questionnaires should be validated and potentially modified in those populations beforehand, or a standardized skin examination protocol should be used.

Prior SO2 exposure promotes airway inflammation and subepithelial fibrosis following repeated ovalbumin challenge

BACKGROUND

Exposure to allergens or air pollutants often leads to asthma exacerbations associated with aggravation of airway inflammation. Although, repeated allergen challenge often induces chronic allergic airway inflammation (CAAI) and airway remodelling, yet, the effects of brief exposure to air pollutants such as SO(2) on development of CAAI and airway remodelling remain to be clarified.

OBJECTIVE

The aim of the experiment was to investigate the effects of acute neutrophilic airway inflammation induced by brief exposure to SO(2) on development of CAAI and subepithelial fibrosis (SEF) in a murine model of asthma.

METHODS

Acute airway inflammation was induced by brief exposure to 50 p.p.m. SO(2) (1 h/d, 3 days). CAAI and SEF in BALB/c mice were induced by repeated challenge with ovalbumin (OVA) for 5 or 9 weeks with or without prior exposure to SO(2). Bronchoalveolar lavage fluid (BALF) eosinophilia as index of CAAI, BALF endothelin-1 (ET-1) and TGF-beta1 levels, morphometric evaluation of fibrotic area beneath subbasement membrane and lung hydroxyproline content (Hyp) as indexes of SEF were monitored.

RESULTS

Exposure to SO(2) led to acute neutrophilic inflammation and epithelial sloughing with profound elevation of BALF ET-1. Repeated OVA challenge resulted in CAAI and SEF along with elevation of Hyp, increase of fibrotic area beneath subbasement membrane and elevation of BALF TGF-beta1. Preceding SO(2) exposure exaggerated BALF eosinophilia, facilitated and enhanced SEF with more significant elevation of BALF ET-1 and TGF-beta1 levels compared with OVA-challenged mice without prior exposure to SO(2). The increase of Hyp was positively correlated with elevation of BALF TGF-beta1 during CAAI (r=0.842, P<0.01).

CONCLUSION

This data demonstrated that SEF developed in parallel with severity and time course of CAAI following repeated OVA challenge. SO(2)-induced acute epithelial injury and neutrophilic inflammation could enhance CAAI and promote SEF, probably through overexpression of ET-1 and TGF-beta1.

Increasing COPD awareness

Early diagnosis and smoking cessation are the only available methods to stop the progression of chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the effects of early detection of airflow limitation (AL) in a population with high risk for COPD, using spirometric screening. Smokers aged 40 yrs with a smoking history of 10 pack-yrs were invited to visit a local outpatient chest clinic for simple spirometry (forced expiratory volume in one second (FEV1) and forced vital capacity (FVC)). Smoking history was recorded, followed by smoking cessation advice relating the results of spirometry to the smoking behaviour. Subjects who did not fulfil the above criteria (younger and/or nonsmokers) were also screened. A total 110,355 subjects were investigated; they were aged 53.5+/-11.5 yrs and 58.2% were males. Of the total amount of subjects, 64% were current smokers, 25.1% were former smokers and 10.9% were lifelong nonsmokers. Spirometry tests were within normal values for 70.3%, and 20.3% showed signs of AL: this was mild in 7.6%, moderate in 6.7% and severe in 5.9%. The remaining 8.3% of subjects presented with a restrictive pattern of ventilatory impairment. Airflow limitation was found in 23% of smokers aged 40 yrs with a history of 10 pack-yrs. This study concluded that large-scale voluntary spirometry screening of the population with high risk for COPD detects a large number of subjects with AL.

Wheezing in Chinese schoolchildren: disease severity distribution and management practices, a community-based study in Hong Kong and Guangzhou

BACKGROUND

Asthma is a common chronic disease and information on its management practices at the community level is helpful in identifying problems and improving asthma care.

OBJECTIVE

To assess the severity status and management of the asthma symptom of wheeze of children at the community level in Hong Kong (HK) and Guangzhou (GZ).

METHODS

Cross-sectional study of children aged 10 years using the International Study of Asthma and Allergic disease in Childhood (ISAAC Phase II protocol). Asthma management and lung function were assessed in 178 (98 from HK and 80 from GZ) randomly selected children with wheeze over the past 12 months.

RESULTS

Eighty-three percent, 11%, 6% and 0% of children suffered from intermittent, mild persistent, moderate persistent and severe persistent asthma, respectively, according to the frequency of their symptoms. Addition of spirometric parameter only changed the asthma severity classification in 2.8% of children. Medications were used by 30.6% and 71.3% of children for wheeze in HK and GZ, respectively. In HK, inhaled beta(2)-agonist (73.3% among the drug users) was the commonest medication used followed by inhaled corticosteroid (ICS) (23.3%). In GZ, inhaled beta(2)-agonist was used by 75.4% of children, but use of ICS (26.3%), oral beta(2)-agonist (26.3%), oral theophylline (45.6%), oral ketotifen (36.8%) and oral steroid (35.1%) were also common. ICS was only used by 11.4% of children with persistent asthma. Ten percent and 18.7% of children in HK and GZ, respectively, had emergency department visits, while 16.3% and 11.6% of children in HK and GZ, respectively, had missed school secondary to asthma over the past 1 year.

CONCLUSIONS

Most children in the community had intermittent asthma and addition of lung function to symptoms did not significantly affect classification of asthma severity. Significant morbidity was seen even in this group of children with mostly intermittent and mild persistent asthma.

Pentaglobin in steroid-resistant severe acute respiratory syndrome

SETTING

The treatment of severe acute respiratory syndrome (SARS) is at best controversial, although there is considerable anecdotal experience to show the benefits of corticosteroid therapy for selected patients. Some patients deteriorate relentlessly despite treatment with antibiotic, corticosteroid and mechanical ventilation.

OBJECTIVE

To attempt to determine the clinical efficacy of pentaglobin, an IgM-enriched immunoglobulin preparation, on 12 severe SARS patients who continued to deteriorate despite corticosteroid and ribavirin therapy.

DESIGN

Retrospective analysis of daily quantitative and radiographic data on the cohort in a regional teaching hospital.

RESULTS AND CONCLUSION

There was significant improvement in radiographic scores, when compared with day 1, on days 5, 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. Similarly, there was significant improvement in oxygen requirement, when compared with day 1, on days 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. There were no reported adverse events attributable to pentaglobin administration. Ten patients made an uneventful recovery after treatment. One elderly man died from cardiorespiratory arrest despite clinical and radiological improvement, and another patient is making good progress. Pentaglobin is safe and probably effective in the treatment of steroid-resistant SARS. A double-blind placebo-controlled study should therefore be considered.

Overview on SARS in Asia and the world

Severe Acute Respiratory Syndrome (SARS) is the first major novel infectious disease to hit the international community in the 21st century. It originated in southern China in November 2002, reached Hong Kong in February 2003 and spread rapidly thereafter to 29 countries/regions on five continents. At the end of the epidemic, the global cumulative total was 8098 with 774 deaths. Seven Asian countries/regions were among the top ten on the list. Mainland China and Hong Kong, SAR, accounted for 87% of all cases and 84% of all deaths. Severe acute respiratory syndrome is caused by a novel coronavirus. It has alarmed the world with its infectivity and significant morbidity and mortality, its lack of a rapid, reliable diagnostic test and lack of effective specific treatment and vaccination. The adverse impact on travel and business around the world, particularly in Asia, has been enormous. Some lessons learnt from this epidemic included: (1) any outbreak of infectious disease can rapidly spread around the world by air travel; (2) early reporting of the outbreak to neighbouring countries/regions and the World Health Organization is essential to prevent international spread; and (3) infection control, tracing and quarantine of contacts are essential to control the epidemic. Many questions remain unanswered, including the origin and pathogenesis of the novel coronavirus, the natural history and the best specific treatment of the disease. The SARS-CoV has probably jumped from an animal host to humans. There is an urgent need to evaluate the human-animal habitat in southern China and to remove animal reservoirs if found.

Epidemiology and cause of severe acute respiratory syndrome (SARS) in Guangdong, People's Republic of China, in February, 2003

BACKGROUND

An epidemic of severe acute respiratory syndrome (SARS) has been associated with an outbreak of atypical pneumonia originating in Guangdong Province, People's Republic of China. We aimed to identify the causative agent in the Guangdong outbreak and describe the emergence and spread of the disease within the province.

METHODS

We analysed epidemiological information and collected serum and nasopharyngeal aspirates from patients with SARS in Guangdong in mid-February, 2003. We did virus isolation, serological tests, and molecular assays to identify the causative agent.

FINDINGS

SARS had been circulating in other cities of Guangdong Province for about 2 months before causing a major outbreak in Guangzhou, the province's capital. A novel coronavirus, SARS coronavirus (CoV), was isolated from specimens from three patients with SARS. Viral antigens were also directly detected in nasopharyngeal aspirates from these patients. 48 of 55 (87%) patients had antibodies to SARS CoV in their convalescent sera. Genetic analysis showed that the SARS CoV isolates from Guangzhou shared the same origin with those in other countries, and had a phylogenetic pathway that matched the spread of SARS to the other parts of the world.

INTERPRETATION

SARS CoV is the infectious agent responsible for the epidemic outbreak of SARS in Guangdong. The virus isolated from patients in Guangdong is the prototype of the SARS CoV in other regions and countries.

Individual allergens as risk factors for asthma and bronchial hyperresponsiveness in Chinese children

The role of allergen sensitization in the development of asthma in the Chinese is not clear. This study aims to determine the relationship of sensitization to individual allergens, and the development of asthma and bronchial hyperresponsiveness (BHR) in schoolchildren from three Chinese cities: Hong Kong, Beijing and Guangzhou. Community-based random samples of 10-yr-old schoolchildren from three Chinese cities were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaires (n=10,902), skin-prick tests (n=3,479), and methacholine challenge tests (n=608). The prevalence rates of wheeze in the past 12 months (Hong Kong, 5.8%; Beijing, 3.8%; Guangzhou, 3.4%) and atopy (Hong Kong, 41.2%; Beijing, 23.9%; Guangzhou, 30.8%) were highest in schoolchildren from Hong Kong. Multivariate logistic regression analyses revealed that sensitization to Dermatophagoides pteronyssinus (odds ratio (OR)=4.48; 95% confidence interval (CI): 3.02-6.66), cat (2.59; 1.67-4.03), Dermatophagoides farinae (2.41; 1.65-3.51) and mixed grass pollen (2.85; 1.24-6.50) were significantly associated with current wheeze. Atopy, defined as having > or = 1 positive skin-prick tests, was not an independent risk factor for current wheeze in children from any of the three cities. Furthermore, atopy (OR=2.53; 95% CI: 1.07-5.97), sensitization to cat (3.01; 1.39-6.52) and D. farinae (3.67; 1.93-6.97) were significantly associated with BHR. The authors confirmed that sensitization to house dust mite and cat was significantly associated with current wheeze and bronchial hyperresponsiveness in Chinese schoolchildren. However, the difference in the prevalence rate of atopic sensitization cannot explain the higher prevalence of childhood asthma in Hong Kong, when compared with those children from Beijing and Guangzhou.

Prevalence of respiratory and atopic disorders in Chinese schoolchildren

BACKGROUND

Epidemiological surveys have shown that the prevalence of asthma in the Asian population is relatively low. Within the Chinese population, schoolchildren from Hong Kong were found to have the highest rate of asthma.

OBJECTIVE

To compare the prevalence of respiratory and atopic disorders, and to assess the role of atopy in the development of asthma, in Chinese schoolchildren from Hong Kong, Beijing and Guangzhou.

METHODS

Community-based random samples of schoolchildren aged 9-11 years from three Chinese cities (Hong Kong, Beijing and Guangzhou) were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaires (n = 10902), skin-prick tests (n = 3479) and skin examination (n = 3479).

RESULTS

The prevalence rates of current wheeze, speech limiting wheeze, rhinoconjunctivitis and flexural dermatitis were significantly more common in Hong Kong than in Beijing or Guangzhou. The atopy rate was also higher in Hong Kong (41.2%) than in Beijing (23.9%) or Guangzhou (30.8%). Atopy was strongly correlated with current wheeze (OR 7.74; 95% CI = 5.70-10.51). Subgroup analyses of children from Hong Kong revealed that children born in mainland China who had subsequently migrated to Hong Kong had a significantly lower rate of allergic symptoms and atopy than those children born in Hong Kong.

CONCLUSION

Using a standardized written questionnaire along with a skin prick test and skin examination, we confirmed that the prevalence of asthma, allergic diseases and atopy was highest in schoolchildren from Hong Kong. Atopic sensitization is an important factor associated with asthma in Chinese children.

Mechanisms of bronchial hyperresponsiveness: the interaction of endothelin-1 and other cytokines

Bronchial hyperresponsiveness (BHR) is a fundamental characteristic of asthma and has become part of a more recent definition of asthma. Data show a close link between bronchial hyperresponsiveness (both transient and persistent) and airway inflammation. Airway inflammation is orchestrated by a complex network of cytokines. It has been considered that endothelin-1 is involved in bronchoconstriction and airway structural remodelling and has several pro-inflammatory properties of potential relevance to asthma. We focus on endothelin-1, its activities and interaction with other cytokines in the pathogenesis of asthma.

The interaction of tumour necrosis factor alpha and endothelin-1 in pathogenetic models of asthma

BACKGROUND

There is evidence that tumour necrosis factor alpha (TNF alpha) may be an important mediator in initiating asthmatic airway inflammation. It has been proposed that endothelin-1 (ET-1) is involved in bronchoconstriction and airway remodelling in asthma. It is not known, however, if there is any interaction between TNF alpha and ET in perpetuating airway inflammation in asthma.

OBJECTIVE

The present study aimed to determine the activities of ET-1 and TNF alpha in ovalbumin-sensitized guinea pigs and their roles in the development of airway inflammation.

METHOD

Twelve guinea pigs were sensitized by ovalbumin injection and aerosol inhalation. ET-1 levels were measured in both bronchoalveolar lavage fluid (BALF) and plasma by 125-labelled endothelin-1 (ET-1) radioimmunoassay. The TNF alpha activity released from alveolar macrophage (AM) in BALF was estimated by ELISA. Cultured bovine airway smooth muscle cells (BASMCs) were treated with TNF alpha (1000 units/5 x 10(4) cells) for different times. ET-1 levels in harvested medium from these cells were measured by radioimmunoassay. Cultured human fetal lung fibroblasts (HFLFs) were incubated with ET-1 (10(-8) approximately 10(-6)M), then 3HTdR incorporation to these cells and cell counting were performed. The effects of ET-1 stimulation on the granulocyte macrophage colony stimulating factor (GM-CSF) gene expression in HFLFs were estimated by using RT-PCR method.

RESULTS

ET-1 levels in both plasma and BALF were significantly higher in ovalbumin-sensitized guinea-pigs compared with those in controls (422.27 +/- 175.0 pg/mL vs 277.311 +/- 88.0 pg/mL, P < 0.05, 81.22 +/- 16.15 vs 49.81 +/- 12.64 pg/mL, P < 0.05) while TNF alpha activity was also significantly increased in the OVA-sensitized group compared with that in the control group (6010 +/- 1900 pg/mL vs 2810 +/- 450 pg/mL, P < 0.05). The ET-1 level in harvested medium of BASMCs rose significantly in 12 h in the TNF-alpha treated group (from < 5 pg/mL to 53.72 +/- 14.3 pg/mL, P < 0.001), and remained at a similar level for 24 h in the TNF alpha treated group. It was shown that ET-1 not only stimulated cell proliferation but also induced GM-CSF mRNA expression in HFLFs.

CONCLUSION

ET-1 levels in both plasma and BALF and TNF alpha release from macrophage are increased significantly in ovalbumin-sensitized guinea-pigs. TNF alpha stimulates ET-1 secretion from cultured BASMCsw; ET-1 accelerates cell proliferation and induces GM-CSF mRNA expression in the human fetal lung fibroblast.

New insights into risk factors of asthma

The 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. Longitudinal 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 bronhospasm in asthmatics. A combination of low concentration of SO2 and NO2 often 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 childhood.

[Short-term energy and protein support in mechanically ventilated patients with acute exacerbation of cor pulmonale]

Twenty-one mechanically ventilated patients with acute exacerbation of cor pulmonale had received home made "Nutritient" via nasal gastric tube as energy and protein support for four weeks (energy supplement 37-45 kcal.kg-1.d-1, protein 1.40-1.67 g.kg-1.d-1). Anthropometry, serum albumin, serum prealbumin were measured on the 1st day and at the end of the 1st, 2nd, 4th week of ventilation. The results were compared with those in 15 age-matched ventilated patients who received routine hospital nasal gastric feeding (energy 24-29 kcal.kg-1.d-1, protein: 0.92-1.09 g.kg-1.d-1). All patients were in protein deficient type malnutrition. At the end of the 1st week of ventilation, serum albumin dropped significantly in both groups, resulting in a status of mixed type malnutrition. At the end of the 2nd week, however, serum prealbumin in the experimental group (24.31 +/- 4.80 mg/dl) returned nearly to normal level, being significantly higher than that in the control group (15.10 +/- 3.10 mg/dl, P < 0.01). At the end of the 4th week, both serum albumin (3.90 +/- 0.31 g/dl) and prealbumin (27.33 +/- 3.30 mg/dl) in experimental group returned to normal, being also significantly higher than those in the control group (3.00 +/- 0.23 g/dl, P < 0.05; 17.11 +/- 3.22 mg/dl, P < 0.01). Anthropometry showed no significant change between the two groups during ventilation. It is shown that nasal tube administration of "Nutritient" provides much higher energy and protein as compared with routine nasal feeding, and enables the patient to overcome protein deficiency and to reach positive nitrogen balance earlier.

[Effects of hypoxia-induced endothelin release on the proliferation of pulmonary artery smooth muscle cells]

On the Co-culture model of pulmonary arterial endothelial cells (PECs) and smooth muscle cells (PSMCs), we studied the effects of hypoxia on the release of endothelin in cultured PECs and whether or not these effects could trigger the proliferation in PSMCs. Increase of the transcription of ET gene in cultured pulmonary arterial endothelial cells was shown when endothelial cells were exposed to hypoxia for 24h (95% N2 + 5% CO2, PO2 40-45mmHg in media), was showed to increase the transcription of ET gene in cultured pulmonary arterial endothelial cells by using situ hybridization method. The secretion of ET-1 from those cells into media by ET-1 radioimmunologic detection while 3HTdr incorporation in cultured PMCs was higher compared with normoxia, and administration of ETAb significantly reduced the increase of the incorporation in those compared with hypoxia alone. These results showed that exposure to hypoxia can promote ET-1 gene expression in PECs as well as release of ET from those cells, which of ET can stimulate DNA synthesis in cultured PMCs. It is suggested that enhanced ET release from PECs under hypoxia could stimulate PSMCs' proliferation which may induce pulmonary vessel remodeling--which may involve in the development of hypoxic pulmonary hypertension.

[Histamine release from mast cell induced by main pathogenic bacteria of respiratory infections in Guangzhou area]

The methodology for isolating rat peritoneal mast cell was established. The main pathogenic bacterial ultrasonicates of respiratory infection in GuangZhou area have been examined for their ability to release histamine from purified rat peritoneal mast cells. The results were as following: (1) 7 pathogenic bacteria can cause direct release of histamine from rat mast cells. The most effective histamine releasers were P. mira (histamine release percent is 26.89% +/- 6.70%), Strep. Pneu (24.16% +/- 3.71%), E. Coli (20.40% +/- 4.83%) and K. Pneu (17.91% +/- 4.60%). (2) Histamine release initiated by bacterial ultrasonicates was completed within 30 minutes E. Coli differed from K. Pneu induced histamine release was independent of its dose. (3) The products of K. Pneu did not induce histamine release directly and bacterial hemolysin may play a potent role in bacteria-induced release of histamine. Our findings provide some evidence for mechanism by which respiratory bacterial infection can precipitate or exacerbate attacks of bronchial asthma.

Is asymptomatic bronchial hyperresponsiveness an indication of potential asthma? A two-year follow-up of young students with bronchial hyperresponsiveness

To determine the possibility that asymptomatic bronchial hyperresponsiveness (BHR) develops into symptomatic asthma, a two-year follow-up study was conducted in 81 students (48 male, 33 female; 11 to 17 years) who were found to have BHR in a 3,067 population survey (BHR group). Eighty-eight age-matched students (48 male, 40 female) with normal bronchial responsiveness served as control subjects. Daily symptom cards were recorded. Peak expiratory flow rate was measured for 24 h when symptoms occurred. Histamine inhalation tests were performed at the beginning of the study and at the end of the first and the second year. In the BHR group, 58 students remained bronchial hyperresponsive at the end of follow-up. Nine of 31 students with initially diagnosed bronchial asthma had their symptoms relieved entirely, but ten asymptomatic students developed asthma. The incidence of newly diagnosed asthma (12.5 percent in the BHR group or 20 percent in the asymptomatic BHR group) and the total percentage of diagnosed asthma (39.5 percent) in the BHR group were significantly higher than those (2.27 percent, 2.27 percent) in the control group. FVC and FEV1 showed no significant difference between two groups. PD20 FEV1 values in newly diagnosed asthmatics were significantly lower than those in asymptomatic students both at the beginning (3.05 +/- 1.56 mumol vs 6.14 +/- 1.60 mumol, p < 0.05) or the end (3.47 +/- 1.73 mumol vs 6.55 +/- 1.51 mumol, p < 0.05). The percentage of early respiratory illness was significantly higher in those with newly diagnosed asthma (80 percent) than in asymptomatic students (22.3 percent), but atopic index and the percentage of parental asthma showed no difference between two groups. In nine asthmatics whose symptoms were relieved entirely in the two-year follow-up, PD20 FEV1 was undetectable within the cumulative dose of 7.8 mumol of histamine in three students and rose from 4.58 +/- 1.85 mumol to 7.62 +/- 1.02 mumol in the remaining six. The higher the BHR, the more likely the students developed asthma. About 45 percent of asymptomatic students with PD20 < or = 3.2 mumol developed asthma in the following two years and 80 percent of them had a history of early respiratory illness, suggesting that they may have subclinical or potential asthma.

[Suppression of pituitary-adrenal axis by triamcinolone acetonide in asthmatics]

To assess the inhibitory effect of triamcinolone acetonide on pituitary-adrenal axis, we measured plasma cortisol, plasma ACTH and performed short ACTH stimulation test before and after injection of 40 mg of triamcinolone acetonide intramuscularly in 34 asthmatic patients. At the same time salivary cortisol levels had been followed up for four weeks in ten of the 34 patients. Maximum adrenal suppression was found in two to three days after the administration. The suppression rates of salivary cortisol, plasma cortisol, plasma ACTH and ACTH stimulation test were 81.5%, 53.2%, 70% and 45.6% respectively. Such suppression lasted for two weeks. Afterwards the secretion of pituitary and adrenal glands recovered gradually. The secretion of plasma ACTH and salivary cortisol returned to normal in four weeks and that of plasma cortisol in five weeks. Triamcinolone acetonide, 40 mg monthly, is comparable with prednisone 10 mg daily, or oral dexamethasone 0.75 mg daily. The inhibitory effect of the steroids on pituitary-adrenal axis was in the order of dexamethasone, triamcinolone acetonide and prednisone.

Bronchial hyperresponsiveness in young students of southern China: relation to respiratory symptoms, diagnosed asthma, and risk factors

A cross sectional study was carried out to determine the prevalence of bronchial hyperresponsiveness and asthma in 3067 students aged 11-17 years in an urban and a rural area of Guangzhou (Canton), China. The methods used included a self administered questionnaire, a histamine bronchial provocation test, and allergen skinprick tests. Bronchial hyperresponsiveness was defined as a 20% fall in FEV1 and peak expiratory flow at a provoking dose of histamine (PD20) less than 7.8 mumol on two occasions four weeks apart. The response rate was 98.0% and 99.2% in the two areas. The prevalence of bronchial hyperresponsiveness was 4.1% and of diagnosed asthma 2.4% in the total population. There were no significant differences in prevalence between the urban and the rural area or between boys and girls. The 11-12 year group had a higher prevalence of bronchial hyperresponsiveness (7.6%) than the older groups. Of the 125 with bronchial hyperresponsiveness, 12.0% were defined as having severe or moderate (PD20 less than 0.8 mumol), 26% mild (0.9-3.2 mumol), and 62% slight bronchial hyperresponsiveness (3.3-7.8 mumol). The severity of bronchial hyperresponsiveness was closely related to diagnosed asthma, wheezing, and cough, though half the students with bronchial hyperresponsiveness were symptom free. The most common allergens were house dust and house dust mite in the city, and hay dust, pollen, and feathers in the rural area. The odds ratios for having respectively slight, mild or moderate, and severe bronchial hyperresponsiveness were 5.9, 21.0, and 30.4 for atopy; 1.9, 1.9, and 7.3 for early respiratory infection; and 3.1, 2.5, and 5.6 for a history of parental asthma.

[Pulmonary Pseudomonas infections]

145 strains of pathogenic pseudomonas had been isolated from the sputum or bronchoscopic aspirate of 1423 patients with pulmonary infections. They were classified into 8 types, among which 31.7% was pseudomonas aeruginosa. Pseudomonas aeruginosa was the dominant causative organism in pulmonary infections of the aged while in presenile ones the organism was mainly Pseudomonas fetid. The incidence of nosnocomial pseudomonas infection in patients of COPD with respiratory failure was 40%, of COPD with pulmonary infection 9.1% and of others 6.6%. 24 pseudomonas carriers with COPD (colonies less than or equal to 10(6)/ml in sputum) had been followed up. 16 out of them became negative in sputum culture without any treatment, while the remaining 8 developed pulmonary pseudomonas infections. 21 patients (14.5%) were found to have other types of pseudomonas infections during antibiotic treatment. Sensitivity tests showed that third-generation cephalosporins and aminoglycosides had definite antimicrobial activity against pseudomonas, the former being more stable and effective than the latter.

A comparison of the available methods for the measurement of histamine in sputum

Sputum samples from patients with chronic bronchitis were assayed for histamine content using a bioassay, and/or fluorometric assay and single or double radioenzymatic techniques. Comparison showed that all the assays produced significant differences in the measurement of sputum histamine. Similarly, it was observed that the assays all showed significant differences in the measurement of histamine released from human basophils. In general the fluorometric assay give the highest values for histamine in sputum and the double-isotope radioenzymatic assay the lowest. In contrast, no differences were found between the bioassay, fluorometric assay and the single-isotope radioenzymatic assay for the measurement of histamine added to Tyrode's solution. These results suggest that in biological samples some of the assays may additionally be measuring metabolites of histamine or other components present in the samples and underline the need to measure the levels of histamine and its metabolites separately in sputum.

Inspired oxygen and oxygen transfer during artificial ventilation for respiratory failure

Arterial oxygenation was measured in patients being ventilated artificially for respiratory failure, initially at the FIO2 that had been selected clinically to achieve PaO2 at least normal, and then at each of two or three progressively increased FIO2 values up to about 0.9. Impairment of oxygen transfer was assessed by the difference between calculated pulmonary end-capillary and arterial oxygen content (Cc'O2-CaO2). Reasons are presented to support the assumption that this value indicates the degree of venous admixture. In patients with severely impaired gas exchange ((Cc'O2-CaO2) greater than 1 ml dl-1), the first increase in inspired oxygen decreased the impairment: less severely impaired lungs showed no change. The observations are consistent with the ventilation/perfusion mismatch hypothesis and do not show that increased oxygen impairs pulmonary oxygenating efficiency.