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Biomedical subjects

N S Zhong

Publications and source records attributed to N S Zhong.

At least 19 recordsLinked to original sources
PubMed2002

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.

Allergens↗
PubMed2001

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.

Asian People↗
PubMed1999

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.

Airway Resistance↗
PubMed1997

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.

Administration, Inhalation↗
PubMed1996

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.

Air Pollution↗
PubMed1994

[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.

Animals↗
PubMed1994

[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.

Aged↗
PubMed1993

[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.

Animals↗
PubMed1992

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.

Adolescent↗
PubMed1991

[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.

Adolescent↗
PubMed1990

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.

Adolescent↗
PubMed1990

[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.

Adult↗