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Biomedical subjects

A M Li

Publications and source records attributed to A M Li.

At least 19 recordsLinked to original sources
PubMed2004

Infection control for SARS in a tertiary paediatric centre in Hong Kong.

Severe acute respiratory syndrome (SARS) is an emerging infectious disease. After the appearance of an index patient in Hong Kong in February 2003, SARS outbreaks occurred rapidly in hospitals and spread to the community. The aim of this retrospective study is to evaluate the effectiveness of a triage policy and risk-stratified infection control measures in preventing nosocomial SARS infection among paediatric healthcare workers (HCWs) at the Prince of Wales Hospital, a general hospital to which children with SARS are referred in Hong Kong. The acute paediatric wards were stratified into three areas: (1) ultra high-risk area, (2) high-risk area and (3) moderate-risk area according to different risk levels of nosocomial SARS transmission. The implementation of different levels of infection control precautions was guided by this risk stratification strategy. Between 13 March and 23 June, 38 patients with probable and suspected SARS, 90 patients with non-SARS pneumonia, and 510 patients without pneumonia were admitted into our unit. All probable SARS cases were isolated in negative-pressure rooms. Twenty-six HCWs worked in the ultra high-risk area caring for SARS patients and 88 HCWs managed non-SARS patients in other ward areas. None of the HCWs developed clinical features suggestive of SARS. In addition, there was no nosocomial spread of SARS-associated coronavirus to other patients or visitors during this period. In conclusion, stringent infection control precautions, appropriate triage and prompt isolation of potential SARS patients may have contributed to a lack of nosocomial spread and HCW acquisition of SARS in our unit.

Cross Infection↗
PubMed2004

Serum levels of cutaneous T-cell attracting chemokine (CTACK) as a laboratory marker of the severity of atopic dermatitis in children.

There are at least 13 scoring systems for the assessment of disease severity in atopic dermatitis (AD). Each system has its problems with interobserver and intraobserver variability. Cutaneous T-cell attracting chemokine (CTACK) is a skin-specific chemoattractant which may correlate with AD severity and obviate the issue of observer reliability. We evaluated whether serum CTACK concentrations were associated with the severity of AD in children according to the SCORing Atopic Dermatitis (SCORAD) index. Thirty-seven Chinese children with AD (23 boys, 14 girls; aged 1-11 years) and 13 controls were recruited. The median (interquartile range) overall SCORAD for AD patients was 29.7 (20.3-49.7). Serum concentrations of CTACK and two other atopy-related chemokines, macrophage-derived chemokine (MDC) and thymus and activation-regulated chemokine (TARC), were measured by sandwich enzyme immunoassay. There were significant correlations between SCORAD (r = 0.394, P = 0.016), its area (r = 0.528, P = 0.001) and intensity components (r = 0.429, P = 0.008) with serum levels of CTACK. The serum concentrations of inflammatory markers MDC and TARC also correlated with the CTACK concentrations (r = 0.618, P < 0.001, and r = 0.587, P = 0.001, respectively). Serum CTACK concentration appears to be a skin-specific objective marker that correlates with various clinical and laboratory parameters of AD.

Biomarkers↗
PubMed2004

Urinary leukotriene E4 correlates with severity of atopic dermatitis in children.

Leukotriene E4 (LTE(4)) is elevated in adults with atopic dermatitis (AD). We evaluated whether urinary LTE(4) as a noninvasive marker correlates with clinical indices of disease activity in children with AD. AD patients aged 18 years or younger were eligible for inclusion in the study. Disease severity over the preceding 3 days was evaluated by the SCORing Atopic Dermatitis (SCORAD) index. Severity of AD over the past 12 months was evaluated by the Nottingham Eczema Severity Score (NESS) in Chinese. Urinary LTE(4) concentration was measured by competitive enzyme immunoassay. One hundred and twenty-six children with AD (82 boys and 44 girls) and 45 controls were recruited. The mean +/- SD urinary log-transformed LTE(4) concentration in AD patients and controls was 2.94 +/- 0.32 and 2.62 +/- 0.20 pg/mg creatinine, respectively (P < 0.0001). SCORAD significantly correlated with NESS (r = 0.681, P < 0.0001). There were significant correlations between urinary LTE(4) concentration and overall SCORAD score (r = 0.270, P = 0.002) and its extent (r = 0.185, P = 0.038) and intensity components (r = 0.247, P = 0.005), but not with NESS. When compared with mild AD, urinary LTE(4) concentrations were higher in patients with moderate-to-severe disease (P = 0.049). Urinary LTE(4) measurement is noninvasive and may be useful in supplementing the SCORAD for following longitudinal changes in AD severity in children. However, the practical value of this assay in a clinical setting remains to be determined.

Adolescent↗
PubMed2003

Clinical presentations and outcome of severe acute respiratory syndrome in children.

Hong Kong has been severely affected by severe acute respiratory syndrome (SARS). Contact in households and health-care settings is thought to be important for transmission, putting children at particular risk. Most data so far, however, have been for adults. We prospectively followed up the first ten children with SARS managed during the early phase of the epidemic in Hong Kong. All the children had been in close contact with infected adults. Persistent fever, cough, progressive radiographic changes of chest and lymphopenia were noted in all patients. The children were treated with high-dose ribavirin, oral prednisolone, or intravenous methylprednisolone, with no short-term adverse effects. Four teenagers required oxygen therapy and two needed assisted ventilation. None of the younger children required oxygen supplementation. Compared with adults and teenagers, SARS seems to have a less aggressive clinical course in younger children.

Administration, Oral↗
PubMed2003

Role of amination of a polymeric adsorbent on phenol adsorption from aqueous solution.

Adsorption of seven phenols, one aromatic carboxylic acid and one sulfonated aromatic acid from aqueous solution, by a hypercrosslinked polymeric adsorbent (CHA-111) and the derivative animated by dimethylamine was compared. The results of different adsorption isotherms indicated that amino group on the polymeric matrix played a significant role on adsorption of almost all the employed compounds. For most employed compounds adsorption capacities increase to different degree and significantly for those with lower value of pK(a). It may be attributed to the enhanced adsorbent-adsorbate interaction for amino group introduced on the polymeric matrix. The empirical Freundlich isotherm equation was employed to interpret the adsorbent-adsorbate interaction. The adsorption enthalpy change indicated the uptake of phenols on MCH-111 to be an enhanced physical adsorption because of the hydrogen-bonding interaction. Adsorption kinetic study of phenols on CHA-111 and MCH-111 was also conducted and amino group on the matrix will reduce the adsorption rate for change of pore size distribution and loss of macroprous volume as well as the hydration effect on the surface partly.

Adsorption↗
PubMed2003

Risk factors for childhood overweight in 6- to 7-y-old Hong Kong children.

OBJECTIVE: To identify risk factors for overweight in Hong Kong children aged 6-7 y. DESIGN: Case-control study. SETTING: Student Health Service Centres, Hong Kong. SUBJECTS: A total of 343 Hong Kong Chinese children aged 6-7 y old categorised into three groups, an overweight group (> or =92 nd centile for BMI), a normal middle-weight group (45th-55th centile for BMI) and a normal low-weight group (< or =8th centile for BMI). MEASUREMENTS: Subjects and their parents/caregivers were interviewed at home. Data on lifestyle habits, dietary habits, family structure and demographic background were collected by questionnaire. A 3-day dietary record was administrated by the parents/caregivers to assess dietary intake of the children. RESULTS: Logistic regression analyses (overweight group compared with middle-weight plus low-weight groups) showed that childhood overweight was significantly associated with parental obesity (BMI > or =25 kg/m(2), Asian reference) (paternal: OR=2.66, 95% CI=1.51-4.70; maternal: 5.07, 2.62-9.79) but not parental overweight (BMI=23-25 kg/m(2)). After adjustment for parental obesity, the odds ratio for childhood overweight was increased by birth weight (<3.0 kg as reference, 3.0-3.5 kg: 2.13, 1.18-3.84; > or =3.5 kg: 4.89, 2.49-9.60) and decreased by sleeping duration (<9 h/day as reference, 9-11 h/day: 0.54, 0.30-0.97; > or =11 h/day: 0.31, 0.11-0.87). Childhood overweight was also significantly associated with higher energy consumption (2.62, 1.20-5.74) and having a father who was a current smoker (2.08, 1.25-3.46). CONCLUSIONS: Although healthy diet and regular exercise will remain the cornerstones of obesity management in children, our data support the view that education about maintaining a healthy weight could be introduced much earlier in those families with high-risk children, as indicated by high parental BMI or high birth weight. The utility and practicality of such an approach should be carefully evaluated before becoming part of any public health policy. Further study of the role of short sleeping duration and parental smoking on childhood obesity development is warranted.

Birth Weight↗
PubMed2003

A controlled study of sleep related disordered breathing in obese children.

BACKGROUND: Unlike the adult sleep related disordered breathing (SDB) patients who are typically obese, the relation between obesity and childhood SDB is not clear. AIMS: To investigate whether obese children are more at risk of obstructive SDB when compared to normal population, and whether this risk is potentiated by the presence of pharyngeal lymphoid tissue. METHODS: Forty six obese children (age 10.8 (SD 2.3) years; BMI 27.4 (SD 5.1)), and 44 sex and age matched normal weight children (age 11.7 (SD 2.1) years; BMI 18 (SD 1.8)) were studied. All children underwent a set of physical examinations (including the upper airways) and sleep studies. RESULTS: The obese children were different from the normal weight children in terms of type (predominantly obstructive), frequency, and severity of respiratory disturbances. Depending on the criteria used, 26% or 32.6% of obese children had SDB; 2.3% of normal controls had OAI > or =1 and 4.5% had RDI > or =5. Presence of SDB was related to presence of tonsils (size >2; range 0-4) (OR 12.67, 95% CI 2.14 to 75.17) and BMI (OR 1.20, 95% CI 1.08 to 1.33). CONCLUSIONS: Results suggest that obese children are at increased risk of obstructive SDB; the presence of any pharyngeal lymphoid tissue enlargement in obese children should therefore be aggressively managed.

Adolescent↗
PubMed2003

The effects of obesity on pulmonary function.

AIMS: (1) To determine the predominant pulmonary function abnormality in our population of obese children; and (2) to assess the correlation between the severity of lung function impairment and the degree of obesity as assessed by dual energy x ray absorptiometry (DEXA). METHODS: Sixty four obese patients underwent physical examination, standardised pulmonary function tests (spirometry, lung volumes, and single breath diffusion capacity for carbon monoxide), and DEXA scan measurements. The trunk and subtotal (total - head) body fat mass were used as surrogate index of body adiposity. RESULTS: Sixteen girls and 48 boys with median age and body mass index (BMI) of 12 years (interquartile range (IQR): 10-14) and 30.1 kg/m2 (IQR: 27.2-32.8) respectively were studied. None of the patients had clinical evidence of cardiopulmonary disease. Reduction in functional residual capacity (median FRC 93% predicted, IQR: 68.5-116.5%) and impairment of diffusion capacity (median DLco 83.5% predicted, IQR: 70.0-100.7%) were the most common abnormalities in our cohort, being observed in 30 (46%) and 21 (33%) patients respectively. Obstructive ventilatory impairment was found in three patients. There was significant negative correlation between the degree of reduction of FRC but not DLco with DEXA scan measurements, but such a relation was not found when BMI was used as the indicator of obesity. CONCLUSION: Reduction in FRC and diffusion impairment were the commonest abnormalities found in our cohort of obese patients. Reduction in static lung volume was correlated with the degree of obesity.

Absorptiometry, Photon↗
PubMed2003

Infection control for SARS in a tertiary neonatal centre.

The Severe Acute Respiratory Syndrome (SARS) is a newly discovered infectious disease caused by a novel coronavirus, which can readily spread in the healthcare setting. A recent community outbreak in Hong Kong infected a significant number of pregnant women who subsequently required emergency caesarean section for deteriorating maternal condition and respiratory failure. As no neonatal clinician has any experience in looking after these high risk infants, stringent infection control measures for prevention of cross infection between patients and staff are important to safeguard the wellbeing of the work force and to avoid nosocomial spread of SARS within the neonatal unit. This article describes the infection control and patient triage policy of the neonatal unit at the Prince of Wales Hospital, Hong Kong. We hope this information is useful in helping other units to formulate their own infection control plans according to their own unit configuration and clinical needs.

Cross Infection↗
PubMed2003

Cough frequency in children with stable asthma: correlation with lung function, exhaled nitric oxide, and sputum eosinophil count.

BACKGROUND: A study was undertaken to assess the correlation between cough frequency in asthmatic children with lung function and two non-invasive markers of airway inflammation. METHODS: Thirty two children of median age 12.0 years (interquartile range (IQR) 9.5-13.4) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring over 17 hours and 40 minutes. Coughing episodes were counted both as individual spikes and as clusters. RESULTS: Complete cough frequency data were available in 29 children (90%) and their median forced expiratory volume in 1 second (FEV1) and eNO were 88.5% (IQR 79.5-98) and 23.9 ppb (IQR 11.4-41.5), respectively. The median number of cough episodes was 14 (IQR 7.0-24.0) which was significantly higher than that of normal children (6.7 (IQR 4.1-10.5), p<0.001). Sputum induction was successful in 61% of the subjects; the median induced sputum eosinophil count was 0.05% (IQR 0-9.0). Cough frequency was found to have a significant positive correlation with eNO (Spearman's r =0.781, p<0.001) but not with FEV1 or sputum eosinophil count (r =-0.270, p=0.157; r =0.173, p=0.508, respectively). CONCLUSIONS: Children with stable asthma have increased cough frequency compared with normal controls and cough frequency was greater during the day than at night. Cough may be a more sensitive marker of airway inflammation than simple spirometry.

Adolescent↗
PubMed2003

Plasma TARC concentration may be a useful marker for asthmatic exacerbation in children.

Recent studies suggested the T-helper cells type-2 lymphocytes-specific thymus and activation-regulated chemokine (TARC) and monocyte-derived chemokine (MDC) are useful inflammatory markers for chronic asthma. However, their roles in assessing the severity of acute asthma are unknown. This study aims to evaluate the serial changes of plasma TARC and MDC concentrations in children with asthmatic exacerbation. All patients with acute asthma were treated with systemic corticosteroid for 5 days. The severity of asthmatic exacerbation was classified according to the Global Initiative for Asthma guidelines. Plasma TARC and MDC concentrations were measured by sandwich enzyme immunoassays. Sixteen children, with a median (interquartile range) age of 9.3 (7.2-10.6) yrs and asthmatic exacerbation, were recruited. Plasma TARC concentration showed inverse correlation with peak expiratory flow rate at presentation. The median plasma TARC concentration was highest during the acute attacks (46 pg x mL(-1)) as compared to those levels at 1 (31 pg x mL(-1)) and 5 weeks (32 pg x mL(-1)) following treatment. The median plasma MDC level similarly decreased from 698 pg x mL(-1) at baseline to 261 pg x mL(-1) 1 week later, but increased back to 574 pg x mL(-1) at 5 weeks. These results suggest that plasma T-helper cells type-2 lymphocytes-specific thymus and activation-regulated chemokine but not monocyte-derived chemokine concentration may be a useful inflammatory marker in assessing asthmatic exacerbation in children.

Acute Disease↗
PubMed2003

Sleeping energy expenditure in paediatric patients with obstructive sleep apnoea syndrome.

OBJECTIVE: To investigate sleeping energy expenditure in paediatric patients with obstructive sleep apnoea syndrome. DESIGN: Retrospective study. Setting. University teaching hospital, Hong Kong. PATIENTS AND METHODS: A retrospective analysis comparing sleeping energy expenditure in patients with confirmed obstructive sleep apnoea syndrome and control subjects matched for age, sex, and ideal weight for body height. Subjects were recruited from the Paediatric Chest Clinic and all had undergone overnight polysomnography and sleeping energy expenditure measurement by open-circuit indirect calorimetry using a metabolic cart and canopy system. The measurements were taken during slow-wave sleep. RESULTS: Twenty-four cases with obstructive sleep apnoea syndrome (apnoea hypopnoea index >5) and 23 control subjects were studied. Mean age and ideal weight for body height were 9.4 (standard deviation, 3.9) years and 152.5% (27.2%), respectively. Mean sleeping energy expenditure corrected for body weight for the cases and the control group were 44.83 (standard deviation, 10.49) Kcal/day and 40.71 (10.60) Kcal/day, respectively. Sleeping energy expenditure was not found to be associated with the severity of obstructive sleep apnoea syndrome (r=0.34, P=0.27). CONCLUSION: A trend towards greater sleeping energy expenditure was found in patients with obstructive sleep apnoea syndrome. Further studies on the metabolic aspects of this condition are required.

Calorimetry, Indirect↗
PubMed2002

Distribution in allele frequencies of predisposition-to-atopy genotypes in Chinese children.

Asthma is one of the most common chronic diseases in childhood; it is caused by a complex interaction between genetic factors and exposure to environmental allergens and irritants. Previous studies using the candidate gene approach showed that asthma was linked to a number of susceptibility genetic loci in Caucasian subjects. There are, however, only a few studies on asthma predisposition genes in the Chinese population. We studied the distribution of allele frequencies of I50V for the interleukin-4 receptor, two polymorphisms in intron 2 and exon 7 for the high-affinity IgE receptor (Fc epsilon RI-beta), R16G and E27Q for the beta(2)-adrenoceptor,and R275Q (824G/A) for CC chemokine receptor 3 in Chinese children.Seventy-six patients, with a mean age of 10.6 years, and 70 age- and sex-matched controls, were studied. Significantly more subjects in the asthma group had specific IgE antibodies against environmental allergens (P < 0.0001; odds ratio, 9.82). Genotyping of the six genetic markers showed that none of the six polymorphisms was associated with asthma in this cohort. The allele frequencies of I50V, R16G, and E27Q in our population were similar to those published for Asian subjects but not Caucasians. The R275Q substitution was a rare finding in our study and in the published reports. Our results demonstrate ethnic differences in polymorphisms of atopy candidate genes. Additional studies involving larger samples are required to investigate the association between asthma or atopy and the genotypes studied to date in Chinese children.

Asthma↗
PubMed2002

Use of tonsil size in the evaluation of obstructive sleep apnoea.

AIMS: (1) To determine the extent to which tonsil size contributes to the severity of obstructive sleep apnoea (OSA) in children; and (2) to assess the use of tonsillar-pharyngeal (TP) ratio in differentiating patients with different severity of OSA. METHODS: Lateral neck radiograph was performed on 35 children referred consecutively to a university paediatric chest clinic for suspected OSA secondary to tonsillar hypertrophy. The tonsil size was determined by measuring the TP ratio on the radiographs. The severity of OSA was assessed by overnight polysomnography. RESULTS: A total of 24 boys and 11 girls (median age 6.2 years) were studied. All presented with symptoms of OSA, and tonsillar hypertrophy was detected on clinical examination. The median apnoea-hypopnoea index (AHI) was 16.93 (interquartile range: 8.41 to 28.29). The median TP ratio was 0.76 (interquartile range: 0.65 to 0.80). AHI was positively correlated with the TP ratio. The clinical tonsil size did not correlate with the AHI or the TP ratio. Using a TP ratio of 0.479, the sensitivity and specificity in predicting cases with moderate/severe OSA (AHI >10) were 95.8% and 81.8% respectively, while the positive and negative predictive values were 92.0% and 90.0% respectively. CONCLUSIONS: Results show that in a population of children with OSA, tonsillar hypertrophy as assessed by lateral neck radiograph correlates positively with the severity of obstructive sleep apnoea. The TP ratio has high sensitivity and specificity in predicting those with moderate/severe disease and this feature may be used as a clinical screening method in prioritising patients with OSA for further assessment.

Child↗
PubMed2002

Respiratory function in patients with thalassaemia major: relation with iron overload.

AIMS: (1) To determine the pattern of respiratory impairment in children with thalassaemia major (TM); (2) to assess the relation between the degree of respiratory impairment and total body iron content. METHODS: Twenty nine TM patients were recruited. All underwent physical examination, standardised pulmonary function tests (spirometry, lung volume, and single breath diffusion capacity for carbon monoxide), and magnetic resonance imaging measurements of the liver. Serum ferritin was measured. The signal intensity ratio of liver to that of paraspinal muscle (T1 weighted sequence) and serum ferritin were used as surrogate index of body iron content. RESULTS: Sixteen boys and 13 girls (median age 14.2 years) were studied. None had clinical evidence of congestive heart failure. Sixteen had normal lung function. Impairment of diffusion capacity (median DL(co) 83.5% predicted) was the most common abnormality, being observed in 34% of patients. Pure restrictive and obstructive ventilatory impairment was found in one and two patients respectively. Five patients had a combination of ventilation and diffusion defects. There was no correlation between the degree of impairment of each respiratory abnormality and body iron content. CONCLUSION: Diffusion impairment was the commonest abnormality found in our cohort of paediatric TM patients. Our data did not support the notion that respiratory function impairment was correlated with body iron content.

Adolescent↗