Jane Yin

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/m2 (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.

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.

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.

Treatment of respiratory syncytial virus infection with recombinant interferon alfa-2a.

A prospective randomised, double blind, controlled trial was conducted in 52 infants to determine whether recombinant interferon alfa-2a (INF-alpha-2a) would reduce the morbidity of acute bronchiolitis and the respiratory syncytial virus shedding time. All infants had a positive direct antigen immunofluorescence test for respiratory syncytial virus. INF-alpha-2a (50,000 IU/kg/day) or placebo was administered by daily intramuscular injection for three consecutive days. Sixteen infants received INF-alpha-2a and 36 received placebo treatment. The two groups were similar in demographic characteristics and initial oxygenation. The treatment group, however, had a significantly higher overall score for severity of illness at the start of treatment. More rapid drop of the clinical score was observed in the INF-alpha-2a group after treatment in the first three days and the two groups had similar clinical severity by day 3. There was no significant difference of the duration of viral shedding in the two groups. In conclusion, the overall clinical improvement was greater in the treatment group over the first three days, but the duration of viral shedding was not altered.

Higher exercise frequency associated with lower blood pressure in Hong Kong adolescents: a population-based study

The aim of this study was to determine the association between blood pressure and the frequency of structured physical training activity in Chinese adolescents. A total of 9558 students aged 11–18 years underwent anthropometric and blood pressure measurements in a cross-sectional growth study. Structured physical training activity was assessed by two simple self-administered questions and parents were asked to complete a questionnaire providing demographic information. Ninety per cent of eligible students participated in the study, of which 94% provided data on physical training frequency for final analysis. Of the boys, 22.6% and of the girls, 14.5% were physically active with extracurricular school exercise at least twice a week. Over half of the students did not regularly exercise except during physical education classes at school. Blood pressure had a positive correlation with body mass index (BMI). Both systolic blood pressure and diastolic blood pressure were substantially decreased with increased training frequency (P<0.05). Logistic regression adjusting for age, family history of hypertension, BMI and sleep duration showed that exercising two or more times a week had a negative relation with hypertension (odds ratio: 0.63, 95%CI 0.47–0.85). In conclusion, structured physical training activity of two or more times a week has a beneficial effect on blood pressure in Hong Kong children aged 11–18 years.

Oxygen consumption by lungs with acute and chronic injury in a rabbit model

Abstract. Objective: To study the oxygen consumption by lungs with acquired acute and chronic injury in a rabbit model. Design: A non-randomized controlled animal study. Subjects and method: Three groups of White New Zealand rabbits were studied to determine the oxygen consumption of the lungs. Group 1 (n=21, controls) consisted of healthy rabbits with normal lungs. The rabbits in group 2 (n=14) had sustained acute lung damage induced by subcutaneous N-nitroso-N-methylurethane and those in group 3 (n=9) had sustained chronic lung damage inflicted by a single dose of intra-tracheal bleomycin. Pulmonary oxygen consumption was estimated from the difference between the whole body oxygen consumption, measured by indirect calorimetry, and systemic oxygen consumption estimated by the Fick method. Measurements and results: Both acute and chronic lung-damaged groups had significantly greater pulmonary oxygen consumption than the control group, both as absolute values [control vs acute vs chronic: 0.25 (0.04) vs 0.76 (0.10) vs 1.77 (0.21) ml/kg per min, p<0.001], and as a percentage of total body oxygen consumption [2.98 (0.47) vs 9.34 (1.39) vs 20.20 (2.11)%, p<0.0001]. Histological evaluation of the severity of lung damage using a lung-injury score revealed significantly higher scores in both lung-injury groups than in the controls. Conclusions: These findings suggest that the lung is an important site of energy loss in subjects with acute and chronic lung injury.

Topical prostaglandin E2 gel for cervical ripening and closure of the ductus arteriosus in the newborn.

The closure time of the ductus arteriosus was investigated in 29 full term babies born vaginally after induction with prostaglandin E2 and in 22 controls. Serial Doppler echocardiography studies showed a significantly prolonged closure time in babies induced by prostaglandin E2. Whether the difference is related to changes in fetal prostaglandin E2 concentration remains to be established.