Rita Yn Tz Sung

Aims: We investigated the therapeutic efficacy of thrombopoietin (TPO) in acute and chronic rat models of heart damage and explored the mechanisms in terms of genome-wide transcriptional changes, phosphorylation signals, and bone marrow endothelial progenitor cell (EPC) levels. Methods and results: Cardiac damage was induced in rat models of (i) acute-doxorubicin (DOX) treatment: single high-dose DOX, four doses TPO, followed up for 5 days; and (ii) chronic-DOX treatment: one low-dose DOX and three doses TPO weekly for 6 weeks, followed up for 11 weeks. Our results demonstrated that TPO treatment led to significant improvements of fractional shortening, cardiac output, and morphologic parameters in both models. In the acute-DOX model, microarray and network analyses showed that DOX damage was associated with changes in a large cohort of gene expressions, of which many were inversely regulated by TPO, including modulators of signal transduction, ion transport, anti-apoptosis, protein kinase B/ p42/p44 extracellular signal-regulated kinase (AKT/ERK) pathways, cell division, and contractile protein/matrix remodelling. Many of these regulations also occurred in chronic-DOX animals, in which TPO treatment reduced morphological damage and cardiomyopathy score, and increased AKT phosphorylation of heart tissues. Thrombopoietin also increased EPC colonies in their bone marrow. Conclusion: Our overall data suggest that TPO promotes cardiac protection from acute- and chronic-DOX insults, possibly mediated by multi-factorial mechanisms including AKT- and ERK-associated restoration of regulatory gene activities critical for normal heart function.

Central body fat is a better predictor than overall body fat for cardiovascular (CV) risk factors in both adults and children. Waist circumference (WC) has been used as a proxy measure of central body fat. Children at high CV risk may be identified by WC measurements. Waist-to-height ratio (WHTR) has been proposed as an alternative, conveniently age-independent measure of CV risk although WHTR percentiles have not been reported. We aim to provide age- and sex-specific reference values for WC and WHTR in Hong Kong Chinese children.

Background: Large population growth surveys of children and adolescents aged 6 to 18 y were undertaken in Hong Kong in 1963 and 1993. The global epidemic of obesity is a major public health concern. To monitor the impact of this epidemic in Hong Kong children and to identify secular changes in growth, a further growth survey was undertaken in 2005/6. Methods: Cross-sectional height and weight measurements of 14,842 children and adolescents aged 6 to 18 y from Hong Kong's 18 districts were obtained during the 2005/6 school year. Percentile curves were constructed using LMS method and sex-specific percentile values of weight-for-age, height-for-age, and BMI-for-age were compared with those data from 1963 and 1993. Results: Secular changes in height, weight and BMI were noted between 1963 and 1993 and between 1993 and 2005/6. In the latter period, greater changes were observed at younger ages, and particularly in boys. On an annual basis, the 1993–2005/6 changes were less than those during 1963–1993. Using the International Obesity Task Force cut-offs, 16.7% of children were overweight or obese in 2005/6, which was a 5.1% increase since 1993. Conclusion: These data provide policy-makers with further evidence of the secular changes in child growth and the increasing obesity epidemic among Hong Kong children.

Paired nasopharyngeal aspirate (NPA) and nasal swab (NS) samples from 475 children hospitalized for acute respiratory infection were studied for the detection of influenza virus, parainfluenza virus, respiratory syncytial virus, and adenovirus by immunofluorescence test, viral culture, and multiplex PCR assay. The overall sensitivity of viral detection with NPA specimens was higher than that obtained with NS specimens.

Oscillometric devices are increasingly used to measure blood pressure (BP). Reference data are limited and have not used devices validated against sphygmomanometric measurements on which current standards are based. BP standards for Chinese children have been based on sphygmomanometry and have not provided height-related or weight-related BP percentiles. BP was measured in 14 842 Hong Kong Chinese schoolchildren aged 6–18 years randomly selected from 36 schools in the 18 Hong Kong districts, using a validated oscillometric device (Datascope Accutorr Plus). Height, weight, heart rate and waist circumference were measured. Percentiles for systolic BP and diastolic BP by sex, age, height and weight were generated. Features associated with systolic BP and diastolic BP in 12 680 children were analysed by univariate and multivariate analysis. Reference BP standards by sex, age, weight and height are presented. BP was associated (in descending order of strength) with weight > height > age > waist circumference > body mass index, and weakly with heart rate (which added considerable influence on multivariate analysis). BP increases similarly with age, height (which can normalize for variations in growth) and weight (which is associated most strongly with BP). BP was associated also with family history of high BP and (inversely) with sleep duration. The study provides oscillometrically measured BP standards for Chinese children, with age-related and sex-related height-specific and weight-specific percentiles. Implications of the findings are discussed. Screening by sex-specific BP–height percentile charts, and then if high, reference to the BP–sex–age–weight table, is suggested.

Education is so strongly emphasized in the Chinese culture that academic success is widely regarded as the only indicator of success, while too much physical activity is often discouraged because it drains energy and affects academic concentration. This study investigated the relations among academic achievement, self‐esteem, school conduct and physical activity level. The participants were 333 Chinese pre‐adolescents (aged 8–12) in Hong Kong. Examination results and conduct grades were obtained from the school records. Global self‐esteem was measured with the Physical self‐description questionnaire (PSDQ), while physical activity patterns of the children were assessed with the Physical activity questionnaire for children (PAQ‐C). Results showed that high academic achievers consistently attained better school conduct marks. However, physical activity level was quite an independent entity that was related neither to academic achievement nor school conduct. Furthermore, regression analyses showed that only academically high‐achieving boys and physically active boys had higher self‐esteem.

Cervical lymphadenopathy is a typical feature in some children with Kawasaki disease, but whether its presence or absence delays diagnosis, thereby increasing the risk of coronary artery abnormalities, has remained uncertain. : The aim of this study is to review the clinical features of Kawasaki disease with particular reference to investigating the relationship of cervical lymphadenopathy to the development of coronary artery lesions. Demographic and clinical data from all the patients entered into the Hong Kong Kawasaki disease registry during 1994 to 2000 were reviewed. The presenting clinical features, echocardiographically monitored coronary artery lesions and influence of cervical lymphadenopathy (> or = 1 nodes > or = 1.5 cm diameter) on clinical onset-to-diagnosis time and response to immunoglobulin therapy are reported. We studied 696 patients (99% Chinese, male/female ratio 1.7:1). Their distribution was inversely related to age. Twenty-four percent of the patients presented with cervical lymphadenopathy, the relative incidence of which was directly related to age. Five percent of patients had demonstrable coronary artery aneurysms at 8 weeks after disease onset. A slightly higher percentage of patients with absence of lymphadenopathy had late diagnosis. No significant positive or negative overall association between cervical lymphadenopathy and coronary artery lesions was observed. Time to resolution of fever after immunoglobulin administration did not differ between those with and without cervical lymphadenopathy. Cervical lymphadenopathy was present in only 24% of the patients with Kawasaki disease, correlating directly with age. Its absence may delay the timing of diagnosis. There was, however, no overall association between lymphadenopathy and coronary lesions.

Background— Doxorubicin (DOX) is an important antineoplastic agent. However, the associated cardiotoxicity, possibly mediated by the production of reactive oxygen species, has remained a significant and dose-limiting clinical problem. Our hypothesis is that the hematopoietic/megakaryocytopoietic growth factor thrombopoietin (TPO) protects against DOX-induced cardiotoxicity and might involve antiapoptotic mechanism exerted on cardiomyocytes. Methods and Results— In vitro investigations on H9C2 cell line and spontaneously beating cells of primary, neonatal rat ventricle, as well as an in vivo study in a mouse model of DOX-induced acute cardiomyopathy, were performed. Our results showed that pretreatment with TPO significantly increased viability of DOX-injured H9C2 cells and beating rates of neonatal myocytes, with effects similar to those of dexrazoxane, a clinically approved cardiac protective agent. TPO ameliorated DOX-induced apoptosis of H9C2 cells as demonstrated by assays of annexin V, active caspase-3, and mitochondrial membrane potential. In the mouse model, administration of TPO (12.5 μg/kg IP for 3 alternate days) significantly reduced DOX-induced (20 mg/kg) cardiotoxicity, including low blood cell count, cardiomyocyte lesions (apoptosis, vacuolization, and myofibrillar loss), and animal mortality. Using Doppler echocardiography, we observed increased heart rate, fractional shortening, and cardiac output in animals pretreated with TPO compared with those receiving DOX alone. Conclusions— These data have provided the first evidence that TPO is a protective agent against DOX-induced cardiac injury. We propose to further explore an integrated program, incorporating TPO with other protocols, for treatment of DOX-induced cardiotoxicity and other forms of cardiomyopathy.

Objective: To compare self-perceptions of physical competences in overweight and in normal weight preadolescent Chinese children. Design: Cross-sectional study. Setting: Three primary schools and a university hospital in Hong Kong. Subjects: A total of 634 children, comprising 558 (462 normal weight, 96 overweight) aged 8–12 y randomly sampled from three primary schools, and 76 similar age overweight children recruited from the community for a diet and exercise intervention programme. Measurements: Height, weight and percentage body fat were measured. Self-perceptions of physical competences were determined by Physical Self-Descriptive Questionnaire (PSDQ). Corresponding actual physical competences were measured by physical fitness tests. Results: Overweight children perceived themselves to have significantly more body fat than normal weight children, with poorer appearance, sports competence, endurance, coordination, flexibility, overall physical self-concept and self-esteem, but to be no less healthy, no less physically active and no less strong. Overweight children performed less well than normal weight children in measures of endurance, coordination and flexibility but better in strength. Poor self-perception of physical competences appeared only partly related to deficiencies in actual physical competences. Conclusion: Overweight children have poorer self-perception of their physical competences but do not perceive themselves to be less strong, healthy or physically active than normal weight children. Exercise programmes for overweight children could be more effective if designed with the knowledge of these self-perceptions. Sponsorship: Research Grants Council of the Hong Kong Special Administrative Region.