Biomedical subjects

A M Li

Publications and source records attributed to A M Li.

At least 19 recordsLinked to original sources

PubMed2006

Induced sputum inflammatory measures correlate with disease severity in children with obstructive sleep apnoea.

OBJECTIVE: To establish the association between airway inflammation and severity of obstructive sleep apnoea (OSA) in children. METHODS: Consecutive children presenting with symptoms suggestive of OSA were recruited. They completed a sleep apnoea symptom questionnaire, underwent physical examination, spirometry, sputum induction and an overnight polysomnography. Adequate sputum contained <50% squamous epithelial cells, and OSA was diagnosed if the obstructive apnoea index was >1. RESULTS: 73 children with a median (interquartile range (IQR)) age of 11.3 (10.0-13.2) years were recruited. There were 21 girls and the median body mass index of the group was 24.0 (18.0-27.0) kg/m2. The most common presenting symptoms were habitual snoring, mouth breathing and prone sleeping position. Sputum induction was successful in 43 (59%) children, of whom 14 were found to have OSA. Children with OSA had significantly greater percentage sputum neutrophil than those without OSA (18.5 (IQR 8.0-42.0) v 4 (IQR 3.0-11.3), p = 0.006). On multiple regression analysis, percentage sputum neutrophil was significantly associated with OSA (odds ratio = 1.1, p = 0.013). CONCLUSION: Children with OSA had airway inflammation characterised by a marked increase in neutrophils. Further studies are needed to confirm these findings and to better define the downstream cellular interactions and molecular pathogenesis in childhood OSA.

Adolescent↗

PubMed2006

Cough frequency in children with mild asthma correlates with sputum neutrophil count.

BACKGROUND: A study was undertaken to measure cough frequency in children with stable asthma using a validated monitoring device, and to assess the correlation between cough frequency and the degree and type of airway inflammation. METHODS: Thirty six children of median age 11.5 years (interquartile range (IQR) 9-14) with stable asthma were recruited. They underwent spirometric testing, exhaled nitric oxide (eNO) measurement, sputum induction for differential cell count, and ambulatory cough monitoring for 24 hours. Coughing episodes were counted both as individual spikes and as clusters. RESULTS: All children had mild intermittent asthma and their median forced expiratory volume in 1 second and eNO were 83.3% (IQR 81.1-97.6) and 56.1 ppb (IQR 37.4-105), respectively. The median number of cough episodes per day was 25.5 (IQR 16-42.8). Sputum induction was successful in 69% of the subjects and cough frequency was found to have a significant positive correlation with sputum neutrophil count (r = 0.833, p = 0.0001). CONCLUSIONS: Children with stable mild asthma have increased cough frequency that might be driven by a neutrophilic inflammatory pathway.

Asthma↗

PubMed2006

Longer term follow up of aerobic capacity in children affected by severe acute respiratory syndrome (SARS).

BACKGROUND: A study was undertaken to investigate the aerobic capacity and pulmonary function of children 6 and 15 months after the diagnosis of severe acute respiratory syndrome (SARS). METHODS: Thirty four patients of mean age 14.7 years completed both pulmonary function and maximal aerobic capacity tests at 6 months. All had normal clinical examination and were asymptomatic. Their exercise responses were compared with a group of healthy controls. Complete data were collected on 27 of the original 34 cases at 15 months. RESULTS: Compared with normal controls, the patient group had significantly lower absolute and mass related peak oxygen consumption (peak V o(2) (p<0.01)), higher ventilatory equivalent for oxygen (p<0.01), lower oxygen pulse (p<0.01), and a lower oxygen uptake efficiency slope (p<0.01) at 6 months. This impairment was unexpected and out of proportion with the degree of lung function abnormality. Residual high resolution computed tomography of thorax (HRCT) abnormalities were present in 14 patients. Those with abnormal HRCT findings had significantly lower mass related peak V o(2) than subjects with normal radiology (p<0.01). Absolute and mass related peak V o(2) in the patient group remained impaired at 15 months despite normalisation of lung function in all patients. CONCLUSIONS: The mechanism for the reduced aerobic capacity in children following SARS is not fully understood, but it is probably a consequence of impaired perfusion to the lungs at peak exercise and deconditioning.

Adolescent↗

PubMed2005

Deletion of the nuclear receptor Nr2e1 impairs synaptic plasticity and dendritic structure in the mouse dentate gyrus.

The spontaneous or targeted deletion of the nuclear receptor transcription factor Nr2e1 produces a mouse that shows hypoplasia of the hippocampal formation and reduced neurogenesis in adult mice. In these studies we show that hippocampal synaptic transmission appears normal in the dentate gyrus and cornu ammonis 1 subfields of adult mice that lack Nr2e1 (Nr2e1-/-), and that fEPSP shape, paired-pulse responses, and short-term plasticity are not substantially altered in either subfield. In contrast, the expression of long-term potentiation is selectively impaired in the dentate gyrus, and not in the cornu ammonis 1 subfield. Golgi analysis revealed that there was a significant reduction in both dendritic branching and dendritic length that was specific to dentate gyrus granule cells in the Nr2e1-/- mice. These results indicate that Nr2e1 deletion can significantly alter both synaptic plasticity and dendritic structure in the dentate gyrus.

Animals↗

PubMed2005

Mal-positioned umbilical venous catheter causing liver abscess in a preterm infant.

Neonatal liver abscess is uncommon, carries a high mortality and is difficult to diagnose. We report an unusual case of liver abscess in a preterm infant presenting with abdominal distension and suspected gastrointestinal perforation, rather than the more usual features of fever, hepatomegaly, abdominal tenderness, right-sided pleural effusion, and leukocytosis. We discuss current treatments for neonatal liver abscess and argue that in view of the high mortality and difficulty in diagnosis, prevention should be the primary objective. We believe that mal-positioning the umbilical venous catheter in the liver substantially increases the life-threatening risk of this complication, and advocate extreme care in the placement and use of these catheters.

Catheterization, Peripheral↗

PubMed2005

RANTES G-401A polymorphism is associated with allergen sensitization and FEV1 in Chinese children.

G-401A polymorphism in RANTES promoter was associated with near-fatal asthma and atopic dermatitis in children. We studied whether gain-of-function mutations in RANTES gene were associated with asthma and atopy-related traits in Chinese children. Plasma total and aeroallergen-specific IgE concentrations were measured using micro-particle immunoassay and fluorescent enzyme immunoassay, respectively. Restriction fragment length polymorphism was used to genotype RANTES G-401A and C-28G. One hundred and twenty-nine asthmatic children and 66 controls were recruited. Their mean logarithmic plasma total IgE concentrations were 2.53 and 1.98, respectively (P<0.0001). RANTES G-401A was not associated with physician-diagnosed asthma (P = 0.408). However, RANTES G-401A allele was significantly associated with IgE sensitization to cat (odds ratio 2.35; 95% CI 1.15-4.77; P = 0.010). Those homozygous for -401A had higher plasma cat-specific IgE levels (P = 0.034). Subjects having -401A were also more likely to have mold-specific IgE (odds ratio 3.82; 95% CI 1.24-12.14; P = 0.007). On spirometry, those with -401A/ A had lower forced expiratory volume in 1-s (FEV1; P = 0.044). RANTES C-28G was not associated with any outcome in this study. In conclusion, the gain-of-function mutation at -401 of RANTES promoter is associated with sensitization to cat and mold allergens and FEV1 in Chinese children.

Adolescent↗

PubMed2005

Resting energy expenditure, oxygen consumption and carbon dioxide production during sleep in children with atopic dermatitis.

BACKGROUND: Pruritus and scratching are cardinal symptoms of atopic dermatitis (AD). Sleep and growth may also be affected in children with moderate-to-severe AD. We evaluated whether resting energy expenditure (REE), oxygen consumption (VO2) and carbon dioxide production (VCO2) in various stages of sleep were influenced by the disease severity. METHODS: Disease severity was evaluated by the scoring atopic dermatitis (SCORAD) index. All-night polysomnography was performed and REE, VO2 and VCO2 were measured. RESULTS: Twenty children (13 boys and seven girls) with AD and eight controls were recruited. The median overall SCORAD for our AD patients was 36.8. The total sleep efficiency was lower in patients with severe AD than that obtained in the control group (median: 72% versus 88%; p = 0.039). When compared with mild-to-moderate disease (SCORAD40) and controls, REE, VO2 and VCO2 in patients with severe AD (SCORAD > 40) did not differ in sleep stages I and II combined, stages III and IV combined or the rapid eye movement (REM) stage. REE, VO2 and VCO2 in these sleep stages did not show significant correlation with the overall and the three components of the SCORAD scores. CONCLUSIONS: Children with AD do not appear to have significant disturbance in their resting energy consumption, oxygen consumption and carbon dioxide production during sleep. These parameters do not appear to correlate with the symptomatology of pruritus and sleep disturbance. We speculate that deranged metabolism during sleep is unlikely in children with AD.

Adolescent↗

PubMed2005

A survey of bathing and showering practices in children with atopic eczema.

We evaluated the emollient use and bathing habits of children with atopic eczema (AE) managed at the paediatric dermatology clinic of a university teaching hospital, using children with noneczematous skin diseases as controls. Disease severity of AE in the preceding 12 months was evaluated by the Nottingham Eczema Severity Score. Three-quarters of patients with or without eczema preferred showering to bathing. Patients with AE were more likely to use bath oils than soap and to use emollients after a bath/shower. Review cases, however, were more likely to take a shower and for a longer time (10-30 min) than first-visit eczema patients. These habits did not vary with season or disease severity. Emulsifying ointment was the most commonly used agent for the bath/shower. Most patients applied emollient immediately after a bath/shower. However there were still significant proportions of AE patients who used soap (40% of first-visit vs. 27% of review cases) and who did not apply emollients after a bath/shower (25% of first-visit vs. 23% of review cases). It is important to determine whether this problem is due to inadequate patient education or whether other factors lead to poor compliance.

Baths↗

PubMed2005

Chemokine response in children with SARS.

The chemokine response of eight children with serologically confirmed severe acute respiratory syndrome (SARS) was longitudinally monitored. All had raised plasma interferon gamma inducible protein (IP-10) concentrations, which suggested an active type 1 T-helper lymphocyte mediated immune response. High circulating IP-10 levels could facilitate viral clearance and might play a role in assisting the recovery of the patients.

Chemokine CCL2↗

PubMed2005

A case-control study of SARS versus community acquired pneumonia.

The clinical, laboratory, and radiological features at presentation of 16 children (<12 years) with severe acute respiratory syndrome (SARS) and pneumonia were compared with 32 age matched patients with community acquired pneumonia for determination of predictive factors that could allow early differentiation of the two conditions. A definitive contact history was the most important predictor for SARS. Raised serum lactate dehydrogenase concentration in the presence of low neutrophil count and serum creatine phosphokinase level at presentation also indicated an increased likelihood of SARS-coronavirus infection in young children.

Biomarkers↗

PubMed2005

Severe acute respiratory syndrome (SARS) in neonates and children.

Severe acute respiratory syndrome (SARS) runs a more benign course in children during the acute phase. Infants born to mothers with the disease did not acquire the infection through vertical transmission. The treatment strategy for children with SARS has not been standardised and is based on adult experience. Thus far, no deaths have been reported in the paediatric age group. Exercise impairment and residual radiological abnormalities were present six months after diagnosis. It is important to assess these patients on a regular basis to detect and provide appropriate management for any persistent or emerging long term sequelae in the physical, psychological, and social domains. This review describes the current understanding of SARS coronavirus infection in newborns and children.

Acute Disease↗

PubMed2005

Non-CF bronchiectasis: does knowing the aetiology lead to changes in management?

The aim of the current study was to review the aetiology of non-cystic fibrosis (CF) bronchiectasis from two tertiary paediatric respiratory units in order to determine how often making a specific aetiological diagnosis leads to a change in management, and to assess the contribution of computed tomography (CT) in determining the underlying diagnosis. The case records of all patients who were diagnosed as having bronchiectasis by CT, currently being seen at the Royal Brompton Hospital and Great Ormond Street Hospital for Children (London, UK), were reviewed. All patients had undergone extensive investigations, and the underlying aetiology and the area of pulmonary involvement (as seen on CT) were recorded. A total of 136 patients were identified; there were 65 young males and the group median (range) age was 12.1 yrs (3.1-18.1). Immunodeficiency, aspiration and primary ciliary dyskinesia accounted for 67% of the cases. In 77 (56%) children, the identification of a cause led to a specific change in management. There was no association between aetiology and the distribution of CT abnormalities. In conclusion, immunodeficiency and other intrinsic abnormalities account for the majority of cases of non-cystic fibrosis bronchiectasis seen in the current authors' units. Computed tomography scans do not contribute towards identifying the aetiology and, most importantly, a specific aetiological diagnosis frequently leads to a change in management.

Adolescent↗

PubMed2005

The six-minute walk test in healthy children: reliability and validity.

The aim of this study was to assess the reliability and validity of the 6-min walk test (6MWT) in healthy children. Chinese secondary school students were randomly recruited. They attended the current authors' unit on two occasions, separated by 2 weeks. Physical examination and standardised maximum incremental exercise testing on a treadmill were performed on the first visit. Spirometry and 6MWT were carried out on the second visit. A randomly selected subgroup was invited to return for repeat 6MWT at an interval of 2-4 weeks. Seventy-eight subjects were recruited; however, four failed to achieve maximal effort on exercise test. The final group included 43 young females and the mean+/-sd age of the subjects was 14.2+/-1.2 yrs. Physical examination was unremarkable in all cases. The mean+/-sd per cent predicted forced expiratory volume in one second was 91.4+/-10.2%. Concurrent validity was demonstrated by good correlation between the 6-min walking distance and maximum oxygen uptake determined on the exercise treadmill. Test-retest reliability was undertaken in 52 subjects, and the intraclass correlation coefficient (95% confidence interval) was calculated as 0.94 (0.89-0.96). In addition, Bland and Altman plots demonstrated a high degree of repeatability. In healthy children, the 6-min walk test is a reliable and valid functional test for assessing exercise tolerance and endurance.

Adolescent↗

PubMed2005

Induced sputum in childhood asthma.

Asthma is characterised by variable degrees of airway obstruction, airway hyper-responsiveness, and chronic airway inflammation. Current guidelines emphasise that inhaled corticosteroid treatment is the mainstay of asthma therapy because it targets the underlying airway inflammation. It is prudent to use the lowest possible dose of inhaled corticosteroid compatible with good asthma control. In clinical practice, the use of or the reduction of inhaled corticosteroid dosage is based on symptoms and lung function, both of which have been shown to have a poor correlation with airway inflammation. The use of induced sputum as a marker of airway inflammation improves asthma monitoring and optimises treatment in adults. This review discusses the technique of sputum induction, its clinical application, and our experience of its use in asthmatic children.

Adrenal Cortex Hormones↗

PubMed2004

Radiological and pulmonary function outcomes of children with SARS.

We examined the radiological and pulmonary function outcomes of children affected with severe acute respiratory syndrome (SARS) at 6 months from diagnosis. Twenty-one female and 26 male Chinese patients (median age, 13.6 years; interquartile range, 9.9-16.0) were studied. In each subject, high-resolution computed tomography (HRCT) of the thorax and pulmonary function were assessed. All children were asymptomatic and had a normal clinical examination. Mild pulmonary abnormalities were detected on HRCT in 16 (34.0%) subjects, including residual ground-glass opacification (n = 5), air trapping (n = 8), and a combination of ground-glass changes and air trapping (n = 3). The need for oxygen supplementation (P = 0.02) and lymphopenia during the course of illness (P = 0.012) were significant risk factors in predicting abnormal HRCT. There were no significant lung function differences between those with and without HRCT abnormalities. Despite complete clinical resolution, a considerable proportion of children affected with SARS had abnormal HRCT findings at 6 months. These abnormalities were more prevalent in those with severe disease. It is important that careful follow-up be carried out to assess the clinical significance and persistence of such abnormalities.

Adolescent↗

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

Hepatic steatosis in obese Chinese children.

OBJECTIVES THE AIMS OF OUR STUDY WERE: (1) to determine the prevalence of asymptomatic hepatic steatosis and presumed nonalcoholic steatohepatitis, in our local population of obese Chinese children referred for medical assessment; and (2) to assess the correlation between severity of ultrasonographic hepatic steatosis and degree of obesity, insulin resistance and serum biochemical abnormalities. DESIGN: Cross-sectional study. METHODS: In total, 84 obese children, 25 girls and 59 boys with median age and body mass index (BMI) of 12.0 years (interquartile range (IR): 9.5-14.0) and 30.3 kg/m(2) (IR: 27.1-33.4), respectively, referred for medical assessment were studied. All subjects underwent physical examination, anthropometric and dual energy X-ray absorptiometry (DEXA) scan measurements and real-time ultrasonographic (US) examination of the liver. Fasting blood samples were collected for the measurement of liver function, hepatitis status, levels of serum glucose and insulin and lipid profile. Degree of fatty infiltration of the liver was graded according to ultrasonic appearance of liver echotexture, liver-diaphragm differentiation in echo amplitude, hepatic echo penetration and clarity of hepatic blood vessels. RESULTS: All recruited subjects had no history of alcohol abuse and tests for Hepatitis B or C virus were negative. Thorough examination showed all of them to be in general good health without signs of chronic liver disease. Hepatic steatosis identified by defined ultrasonic appearances was diagnosed in 65 subjects (77%); 17 girls and 48 boys. The severity of fatty liver was positively related to anthropometric measurements including BMI, waist and hip circumference, subscapular skinfold thickness; insulin resistance markers [QUICKI and homeostasis model assessment (HOMA)], and hypertriglyceridaemia. Multvariate ordinal regression analysis showed that BMI and raised alanine aminotransferase (ALT) were positively associated with fatty liver. Combination of hepatic steatosis with raised ALT (presumptive NASH) was found in 19 subjects (24%). This group of patients had significantly higher waist hip ratio and conicity index compared to those with isolated hepatic steatosis. Boys with presumed NASH were also found to have significantly higher insulin resistance. CONCLUSION: Nonalcoholic fatty liver disease (NAFLD) was common among our cohort of obese children referred for medical assessment. The prevalence of simple steatosis and presumed NASH was 77 and 24%, respectively. The severity of US steatosis was positively correlated with BMI, raised ALT, insulin resistance and hypertryglyceridaemia. Ultrasonography being noninvasive and readily available could be used for the monitoring of the progression of hepatic steatosis. Further longitudinal studies are required to determine the natural disease progression and the role of insulin resistance and other factors in the pathophysiology of NAFLD.

Adolescent↗

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↗