The mediating role of Internet addiction in depression, social anxiety, and psychosocial well-being among adolescents in six Asian countries: a structural equation modelling approach.

OBJECTIVES: This study examines the associations of Internet addiction with social anxiety, depression, and psychosocial well-being among Asian adolescents. A self-medication model conceptualizing Internet addiction as a mediating role in relating depression and social anxiety to negative psychosocial well-being was tested. STUDY DESIGN: A cross-sectional survey. METHODS: In the Asian Adolescent Risk Behavior Survey (AARBS), 5366 adolescents aged 12-18 years from six Asian countries (China, Hong Kong, Japan, South Korea, Malaysia, and Philippines) completed a questionnaire with items of the Internet Addiction Test (IAT), Social Anxiety Scale for Adolescents (SAS-A), Center for Epidemiological Studies Depression Scale (CESD), Self-Rated Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA-SR) in the 2012-2013 school year. Structural equation modelling was used to examine the mediating role of Internet addiction in depression, social anxiety, and subjective psychosocial well-being. RESULTS: Significant differences on the scores of IAT, SAS-A, CESD, and HoNOSCA-SR across the six countries were found. The proposed self-medication model of Internet addiction received satisfactory goodness-of-fit with data of all countries. After the path from social anxiety to Internet addiction had been discarded in the revised model, there was a significant improvement of the goodness-of-fit in the models for Japan, South Korea, and the Philippines. CONCLUSIONS: Depression and social anxiety reciprocally influenced, whereas depression associated with poorer psychosocial well-being directly and indirectly through Internet addiction in all six countries. Internet addiction mediated the association between social anxiety and poor psychosocial well-being in China, Hong Kong, and Malaysia.

Hedgehog signaling induces osteosarcoma development through Yap1 and H19 overexpression.

Osteosarcoma is one of the most common bone tumors. However, the genetic basis for its pathogenesis remains elusive. Here, we investigated the roles of Hedgehog (Hh) signaling in osteosarcoma development. Genetically-engineered mice with ubiquitous upregulated Hh signaling specifically in mature osteoblasts develop focal bone overgrowth, which greatly resembles the early stage of osteosarcoma. However, these mice die within three months, which prohibits further analysis of tumor progression. We therefore generated a mouse model with partial upregulated Hh signaling in mature osteoblasts and crossed it into a p53 heterozygous background to potentiate tumor development. We found that these mutant mice developed malignant osteosarcoma with high penetrance. Isolated primary tumor cells were mainly osteoblastic and highly proliferative with many characteristics of human osteosarcomas. Allograft transplantation into immunocompromised mice displayed high tumorigenic potential. More importantly, both human and mouse tumor tissues express high level of yes-associated protein 1 (Yap1), a potent oncogene that is amplified in various cancers. We show that inhibition of Hh signaling reduces Yap1 expression and knockdown of Yap1 significantly inhibits tumor progression. Moreover, long non-coding RNA H19 is aberrantly expressed and induced by upregulated Hh signaling and Yap1 overexpression. Our results demonstrate that aberrant Hh signaling in mature osteoblasts is responsible for the pathogenesis of osteoblastic osteosarcoma through Yap1 and H19 overexpression.

Risk factors and outcomes of childhood obesity in Hong Kong: a retrospective cohort study.

1. Onset of obesity is related to age, gender, pubertal stage, dietary habits, and parental occupation. Targeting the high riskgroups may help curb obesity in children. 2. Obesity may lead to poor self-esteem and potential psychosocial risk. The psychosocial impact of obesity could be more pronounced in girls than boys. 3. The association between obesity and psychosocial health could be bi-directional. Improving psychosocial health could be beneficial in weight management for normal-weight and obese children. 4. Obesity is associated with higher blood pressures.

The risks of disordered eating in Hong Kong adolescents.

OBJECTIVE: This study examines the risks of disordered eating among Hong Kong adolescents. SUBJECTS: A total of 893 students (12-18 years old) participated in a cross-sectional study in 2007. METHODS: Students' height and weight were measured and the Eating Attitudes Test (EAT-26) was completed. The risks of disordered eating were assessed by EAT-26 results and weight status. Sex differences in the risks of disordered eating were examined by logistic regression models with adjustment for age. RESULTS: Based on the EAT-26 results, 18.5% of boys and 26.6% of girls were at risk of disordered eating with a significant adjusted odds ratio (OR) of 1.58 [95% confidence interval (CI) 1.15-2.18] for sex. A significant OR of 1.60 (95%CI 1.21-2.13) for sex was also obtained when both EAT-26 results and weight status were used for the screening. CONCLUSIONS: Hong Kong adolescent girls have a higher risk of disordered eating than boys. EAT-26 results together with measured weight status are useful criteria for screening disordered eating attitudes and behaviors in adolescents.

Dental health behaviours among early adolescents in Hong Kong.

OBJECTIVES: This study aimed to investigate the prevalence and socioeconomic differences in dental health behaviours among Hong Kong early adolescents. METHODS: A cross-sectional survey was conducted among 4927 students (44.7% boys) aged 14-15 from 36 secondary schools in 2000-2001. Students reported their socioeconomic information and dental health behaviours using the Health Related Behaviour General Questionnaire (HRBGQ). Logistic regression models were used to determine the adjusted odds ratios of regular tooth brushing (at least twice daily), weekly use of dental floss (in the past 7days) and annual dental visit (in the past 12months) for different socioeconomic characteristics. RESULTS: Of the subjects, 77.8% reported to have brushed regularly, but only 22.3% used dental floss weekly and 37.9% had annual dental visit. Male gender and Chinese ethnicity were significantly associated with lower odds of regular brushing, use of dental floss and annual dental visit. Two or more siblings and not living with both parents were also significantly associated with lower odds of regular brushing and annual dental visit. Furthermore, students living in non-private housing were significantly less likely to have annual dental visit than those in private housing. CONCLUSIONS: Regular brushing was common, but not use of dental floss and annual dental visits among Hong Kong early adolescents. In general, socioeconomic disparity in dental health behaviours was observed. Extending the existing government-run dental health programmes to secondary school students in Hong Kong is warranted.

Overexpression of epidermal growth factor induced hypospermatogenesis in transgenic mice.

The in vivo role of epidermal growth factor (EGF) is not well defined even though its effects on culture cells were well studied. To understand the developmental, physiological, and pathological roles of EGF, we have generated transgenic mice widely expressing human EGF with the use of the beta-actin promoter. EGF and transforming growth factor alpha (TGFalpha) bind with equal affinity to the EGF receptor, a transmembrane tyrosine kinase, to trigger various biological responses. EGF and TGFalpha signaling are implicated in the development of the reproductive system. EGF also plays a physiological role in reproduction. Removal of the salivary gland in rodents, which reduces circulating EGF, reduces spermatogenesis, which can be corrected by EGF replacement. Here we show that in our transgenic males, only few post-meiosis II gametes were found, and the mice were sterile. This resembles a common cause of infertility in humans. Furthermore, the transgenic males had reduced serum testosterone. Our findings contrast the previous report on transgenic mice overexpressing TGFalpha in testis, which showed normal spermatogenesis. These data suggest that EGF is the active ligand for EGF receptor reported in germ cells, and proper EGF expression is important for completion of spermatogenesis.

Utilization of the Government dental service by Chinese civil servants in Hong Kong.

A sociological study was conducted in 1987 on a sample of 490 Hong Kong Chinese civil servants for the purpose of investigating factors which influenced their utilization of a freely available Government dental service. The proportions of regular, irregular and non-users of the dental service were 69, 18, and 13% respectively. Regular users had a higher educational standard and income level than the other two user-types. Most of the regular users attended the dental clinics for a check-up. The irregular users did not regularly utilize the service mainly because it took a long time to obtain an appointment. Non-users referred to the long waiting time to obtain an appointment and to their perception of not having dental problems when asked to give their main reasons for not utilizing the dental service. The majority of the user-types considered that shortening the waiting time and employing more dentists would increase the utilization of the Government dental service.

Characterization of thromboxane A2 receptors in the human fetal placental vessels and umbilical vein.

An in vitro examination has been made of the thromboxane A2 receptors in human fetal placental villous vessels and umbilical veins utilizing the TxA2 agonist U46619 and its competitive antagonist AH22921. U46619 was a potent constrictor of both preparations. The EC50 were 25.3 nmol/l (s.e.m. = 2.5, n = 8) for causing constriction of perfused villous vessels and 22 nmol/l (s.e.m. = 5, n = 17) for contraction of the venous longitudinal strip. AH22921 competitively antagonized responses to U46619 in both preparations. The pA2 values were not significantly different and their 95% confidence limits, obtained for its ability to antagonize responses to U46619 in villous vessels and the umbilical vein, were 8.0 (7.3-8.8) and 7.1 (6.3-7.9) respectively. It is concluded that TxA2 receptors in both the human fetal placental villous vessels and umbilical vein may be similar. They also may be similar to those in human platelets and pulmonary blood vessels.

Effects of vasoactive autacoids on the human umbilical-fetal placental vasculature.

Studies have been made of the effects of autacoids on vascular tone of the human perfused fetal umbilical vein and placental lobule. The thromboxane A2 (TxA2)-mimetic substance U46619, 5-hydroxytryptamine and bradykinin were powerful constrictors of the vein. Prostaglandins E2 (PGE2), F2 alpha (PGF2 alpha), adrenaline, noradrenaline, histamine and angiotensin II were much less potent. Venoconstriction caused by U46619, bradykinin and 5-hydroxytryptamine was reduced during inhibition of phospholipase A2 with mepacrine. Responses to U46619 were also reduced after inhibition of cyclo-oxygenase with indomethacin whereas those to bradykinin and 5-hydroxytryptamine were potentiated. In the placenta U46619 was the most potent vasoconstrictor, bradykinin, 5-hydroxytryptamine, angiotensin II, PGE2 and PGF2 alpha being 10-100 times less active. Responses to U46619 were reduced by either mepacrine or indomethacin. Arachidonic acid caused umbilical venoconstriction but vasodilatation in the placenta. Both effects were reduced by indomethacin. Prostacyclin (PGI2) caused vasodilatation in both preparations. It is suggested that TxA2 in the placenta and TxA2, 5-hydroxytryptamine and bradykinin in the umbilical vein could contribute to control of vascular smooth muscle tone. Their vasoconstrictor effects are partly indirect and affected by the concomitant local release of eicosanoids. The results add support to previous conclusions that these autacoids may normally have important influences on blood flow in the fetal extra-corporeal circulation. Agents inhibiting their synthesis, eg non-steroidal anti-inflammatory agents, should only be prescribed during pregnancy with these facts in mind.