Pathological Internet use and associated factors among university students in Hong Kong.

1. Among university entrants, the prevalence of pathological Internet use (PIU) increased more than three-fold (from 5.0 to 15.7%) after 18 months of university life. Psycho-social factors such as depression, life dissatisfaction, and use of the Internet for recreational purposes were associated with the development of PIU. 2. University health workers should be aware that PIU is associated with inferior mental well-being, increased sleeping disorders, and deterioration of family relationships. Special attention should be given to Mainland Chinese students and those with pre-existing psychological problems, as they are more prone to developing PIU. 3. Most university students with PIU were unaware of the health implications of the condition and thus not motivated to seek help. Health workers must take a pro-active approach.

Exploring predictors influencing intended and actual acceptability of the A/H1N1 pandemic vaccine: a cohort study of university students in Hong Kong.

OBJECTIVES: To investigate the factors associated with the uptake of influenza A/H1N1 vaccination by university students, and to examine the relationship between intention and actual vaccination. STUDY DESIGN: Prospective cohort study. METHODS: A baseline survey was conducted among students at the Chinese University of Hong Kong in 2009 to collect data on demographics, pandemic risk perceptions and self-reported intention to be vaccinated in the future. A follow-up survey was conducted in 2011 using an online survey platform collecting information on actual vaccine uptake behaviour, and vaccine attitudes, knowledge and perceptions. RESULTS: Self-reported intention to be vaccinated in 2009 was significantly associated with actual vaccine acceptance. Vaccine perceptions (attitudes and knowledge) were found to be a better predictor of vaccine acceptance than disease risk perceptions. Being a medical or science student and receiving health advice about vaccination from a doctor or school-endorsed advertisement were also found to be predictors of vaccine acceptance. CONCLUSIONS: University students in Hong Kong were wary of the A/H1N1 vaccination campaign, as revealed by their low uptake rate and doubts about the vaccine. Knowledge of the pandemic and vaccine was high in this population, but feelings of susceptibility were low. The results indicate a need to provide tailored messages emphasizing the importance of vaccination and the efficacy of the vaccine in the future.

Brief report: Predictors of heavy Internet use and associations with health-promoting and health risk behaviors among Hong Kong university students.

To examine the correlates of heavy Internet use and determine the associations of heavy Internet use with various health risk behaviors and health-promoting behaviors among Chinese adolescents, an anonymous, self-administered health behavior questionnaire was completed by 2427 matriculants into a Hong Kong university (mean age=18.9 y) and returned at compulsory health examination. Of students, 14.8% reported heavy Internet use (>4h/day) and such use was associated with lower likelihood of engaging in health-promoting activities such as exercising and seeking medical care. At the same time, heavy Internet use was correlated with multiple risk behaviors such as skipping meals and sleeping late as well as poorer health outcomes such as higher likelihood of being overweight or having hypersomnia. Given the double burden of poorer health outcomes and fewer health-promoting behaviors, heavy Internet users represent a particularly challenging group for adolescent health promotion.

Achlya sp. Dermatitis in an American Alligator (Alligator mississippiensis).

Oomycetes are water moulds in the kingdom Protista and are not considered true fungi due to the structural lack of chitin and ergosterol. Many oomycetes are pathogenic, such as Pythium spp., and many fish are prone to Saprolegnia spp. infections, particularly in stressful farming situations. A juvenile American alligator (Alligator mississippiensis) was presented for necropsy examination with white, gelatinous, raised lesions over ulcerated regions of skin on the limbs and tail. The alligator came from a hatchery with age-divided enclosures, and several of the animals within the same enclosure showed similar lesions. Numerous hyphae with non-parallel walls and sparse, non-dichotomous branching were observed histologically on Gomori's methenamine silver staining within the ulcers. Although no organisms were detectable via polymerase chain reaction testing of fresh or formalin-fixed tissues, the organism was cultured and sequenced as an Achlya sp., an infrequently identified oomycete. To the author's knowledge, this is the first description of an oomycete infection within the class Reptilia.

Ly49 C/I-dependent NKT cell-derived IL-10 is required for corneal graft survival and peripheral tolerance.

Similar to their activity on NK cells, Ly49 molecules play a pivotal role in influencing how NKT cells respond. It is known that Ly49 C/I is an inhibitory receptor capable of down-modulating proliferation, IFN-gamma response, and cytotoxic activity in cells that express it. In a model of peripheral tolerance induced via the eye, we observed that Ly49 C/I-positive, invariant NKT cells were required. To test if the NK inhibitory receptor functionally contributed to tolerance development, we used blocking antibody, in vivo and in vitro, to interfere with the development of antigen-specific suppression. A result of blocking ligation of Ly49 C/I inhibitory receptor prevented NKT cell production of IL-10 and the subsequent development of tolerance. Ly49 C/I-blocking antibodies also prevented corneal graft survival, a phenomenon dependent on eye-induced tolerance. Furthermore, in the presence of TCR stimulation, cross-linking of Ly49 C/I on CD4(+) NKT cells stimulated an increase in IL-10 mRNA and a decrease in IFN-gamma. The concept of Ly49 inhibitory receptors regulating immune reactivity to self by regulating immune activity of individual cells is thus expanded to include a role for the inhibitory receptors in the more global process of peripheral tolerance to foreign antigens.

An in vivo investigation on the wound-healing effect of two medicinal herbs using an animal model with foot ulcer.

BACKGROUND/AIM: Over 190 million people in the world suffer from diabetes mellitus. Diabetics are 25 times more likely to have a leg amputated because of unhealing foot ulcers. Herbal medicine has been used in China to salvage the ulcerated limb. With the aim to study the efficacy of two commonly used herbs for ulcer healing, namely Radix Astragali and Radix Rehmanniae, a good animal model needs to be developed for a proper in vivo investigation. METHODS: Firstly, a diabetic animal model was established by streptozotocin injection. Then standard wounds were created on the feet of the diabetic rats. Digital photographs were taken and analyzed by a novel image analysis software. RESULTS: The average ulcer area in the Radix Rehmanniae treatment group was 11.45 mm2, which was significantly smaller than the 15.12 mm2 in the water treatment group (p = 0.04). Radix Astragali, on the other hand, was found to have no significant effect on ulcer shrinkage. CONCLUSION: Further investigation is needed for the identification of the active principles of Radix Rehmanniae.

In vitro antidiabetic activities of five medicinal herbs used in Chinese medicinal formulae.

Fructus Corni, Fructus Schisandrae Chinensis, Poria, Rhizoma Alismatis and Rhizoma Dioscoreae are commonly used in traditional Chinese medicine for diabetes treatment. They are also the component herbs of an antidiabetic foot ulcer formula with demonstrated clinical efficacy. Although some of these herbal extracts were previously shown to possess in vivo antidiabetic effects (i.e. lowering blood glucose levels), the underlying mechanisms remain elusive. The objective of this study is to investigate the possible antidiabetic mechanisms of these individual herbs, using a systematic study platform which includes four in vitro tissue models: glucose absorption into intestinal brush border membrane vesicles (BBMV), gluconeogenesis by rat hepatoma cell line H4IIE, glucose uptake by human skin fibroblasts cell line Hs68 and mouse adipocytes 3T3-L1. All tested herbs showed significant in vitro antidiabetic effects in at least two models. Fructus Schisandrae Chinensis, Poria, Rhizoma Alismatis and Rhizoma Dioscoreae showed significant inhibitory effects in the BBMV glucose uptake assay. All tested herbs showed significant stimulatory effects to the glucose uptake of Hs68 and 3T3-L1 cells, except Poria and Rhizoma Dioscoreae which were not effective to Hs68 and 3T3-L1 respectively. However, none of the tested herbs inhibited hepatic gluconeogenesis. In conclusion, the five herbs exhibited distinct antidiabetic mechanisms in vitro and hence our investigations provided scientific evidence to support the traditional usage of these herbs for diabetic treatment in medicinal formulae.

Influence of an anti-diabetic foot ulcer formula and its component herbs on tissue and systemic glucose homeostasis.

Complications of diabetes impose major public health burdens worldwide. The positive effect of a Radix Astragali-based herbal preparation on healing diabetic foot ulcers in patients has been reported. Formula 1 is also referred as the 'Herbal drink to strengthen muscle and control swelling'. This formula contains six Chinese medical herbs, including Radix Astragali, Radix Rehmanniae, Rhizoma Smilacis Chinensis, Rhizoma Atractylodis Macrocephalae, Radix Polygoni Multiflori Preparata, and Radix Stephania Tetrandrae. Three of these herbs (Radix Astragali, Radix Rehmanniae, Rhizoma Atractylodis Macrocephalae) are commonly used in different anti-diabetic formulae of Chinese medicine. The objective of the current study is to use an interdisciplinary approach to test the hypothesis that Formula 1 and its components influence tissue and systemic glucose homeostasis. In vitro and in vivo models have been established including: (1) glucose absorption into intestinal brush border membrane vesicles (BBMV); (2) gluconeogenesis by H4IIE hepatoma cells; (3) glucose uptake by 3T3-L1 adipocytes and Hs68 skin fibroblasts; (4) normalization of glycaemic control in a diabetic rat model. The results of in vitro studies indicated that all herbal extracts can modify cellular glucose homeostasis. Since Formula 1 and Rhizoma Smilacis Chinensis extracts demonstrated potent effects on modifying glucose homeostasis in multiple tissues in vitro, they were further studied for their anti-diabetic activities in vivo using a streptozotocin (STZ)-induced diabetic rat model. The results showed that Formula 1 and Rhizoma Smilacis Chinensis extracts did not significantly improve oral glucose tolerance or basal glycaemia in diabetic rats. In conclusion, the anti-diabetic foot ulcer Formula 1 contains ingredients active in modifying tissue glucose homeostasis in vitro but these biological activities could not be associated with improved glycaemic control of diabetes in vivo.

PCR cycle sequencing protocol for population mitochondrial cytochrome b analysis.

Laboratories intending to adopt cycle sequencing of PCR products in their routine analysis often face a confusing range of methods and kits. Through the study of mitochondrial cytochrome b, we have shown that clean and highly reproducible sequences could be obtained by using a combination of existing simple and economical methods in the preparation of DNA templates, PCR, purification of PCR products and sequencing. Our protocol is useful in itself or as a standard in typing other PCR-amplified DNA at the population level.

FRAXAC1 and DXS548 polymorphisms in the Chinese population.

The fragile X syndrome is the most common inherited form of mental retardation. Haplotype studies using FRAXAC1 and DXS548 polymorphic markers flanking the fragile site have demonstrated linkage disequilibrium at the FMR1 locus. We investigated the association of the FRAXAC1, DXS548 and CGG alleles between normal subjects and mentally retarded (MR) patients of unspecified cause who do have fragile X syndrome. We have evaluated the FRAXAC1 site in 390 normal subjects and 321 MR patients and the DXS548 site in 146 normal and 319 MR subjects. Both FRAXAC1 and DXS548 alleles were determined by application of the polymerase chain reaction. When compared with Caucasians, the normal Chinese population has a different FRAXAC1 allele distribution. There are more AC18 repeat alleles and fewer AC19 repeat alleles. The DXS548 allele distributions were similar between Chinese and Caucasians. The same distribution pattern of FRAXAC1 alleles was found in both normal subjects and MR patients, but there were significant differences in the distribution patterns of DXS548 alleles. The FMR1 CGG-DXS548 and FRAXAC1-DXS548 haplotype distribution between normal subjects and MR patients also differed significantly. Our results suggest a possible association between DXS548 alleles and non-FRAXA mental retardation.

Trinucleotide CGG repeat in the FMR1 gene in Chinese mentally retarded patients.

The fragile X syndrome of mental retardation is related to the number of trinucleotide CGG repeats at the 5'-untranslated region of the FMR1 gene located on the X-chromosome. We have studied X-chromosomes from 649 unaffected Chinese subjects and 324 patients with mild mental retardation. All study subjects were unrelated. The CGG repeat number was analysed by electrophoresis of a polymerase chain reaction followed by gel transfer and hybridisation with a 32P-labeled (CCG)5 probe. The DNA samples having detectable CGG expansion were further analysed by Southern blot analysis with probe StB12.3 after restriction digestion by EcoR I and Eag I. For the unaffected Chinese subjects, a different distribution pattern of CGG allele size from Caucasians was observed. It was a bimodal pattern and the CGG repeat number ranged from 19 to 54. The most common CGG repeat allele was 29 compared with 30 in Caucasians. The second mode appeared at 36 repeats. There was mild statistical difference in the repeat patterns between the mentally retarded patients and unaffected subjects, although the essential features were similar. Among the mentally retarded patients, one male had an unmethylated full mutation and one female had a full mutation. The fragile X prevalence was 0.6%, which is lower than two previous studies in Chinese mentally retarded patients utilising cytogenetic analysis. Our results indicate that a large-scale screening program would be worthwhile to determine the prevalence of the fragile X syndrome in the Chinese population.

A murine model of interlamellar corneal transplantation.

AIMS/BACKGROUND: There are more reagents and information available for immunological studies in the mouse compared with other animals. Unfortunately, the mouse penetrating keratoplasty model is associated with high background inflammation which hinders study of the immune response to the graft. To mitigate this drawback, a murine orthotopic corneal interlamellar transplantation model with mild non-specific inflammation was developed. METHODS: A 1.5 mm diameter full thickness donor corneal button was placed in a 2 mm diameter recipient corneal interlamellar pocket without placement of a suture. The clinical course of graft status was studied daily for 60 days in 30 allografts (donor strain CBA 101 (H-2k) to recipient NIH (H-2q) and 30 syngeneic grafts (NIH to NIH) by slit lamp biomicroscopy and scored for neovascularisation, opacity, oedema, and granularity. In another cohort of animals, histological observation was performed after 30 minutes and on days 10, 20, 30, and 40 after transplantation (four allografts and four syngeneic grafts per time point). Histological study was also performed on grafts without donor epithelium and on interlamellar pockets without grafts. RESULTS: There was significantly more neovascularisation (NV), opacity, oedema, and granularity in 24/30 allografts (80%) than in syngeneic grafts. Such grafts were defined as rejected. The median time to rejection was 21 days (range 18 to > 60 days). By histology, some allografts showed moderate to heavy cell infiltration which correlated with clinical scores of NV (4-5), opacity (1-3), oedema (1-3), and granularity (1-3). Such infiltration was absent in other allografts and syngeneic grafts. CONCLUSION: Surgically, corneal interlamellar transplantation could be accomplished in the mouse and rejection could be clearly defined. The model can therefore be useful for in situ study of cell and molecular aspects of corneal graft rejection.

Dynamic imaging and tracer kinetic modeling for emission tomography using rotating detectors.

When performing dynamic studies using emission tomography the tracer distribution changes during acquisition of a single set of projections. This is particularly true for some positron emission tomography (PET) systems which, like single photon emission computed tomography (SPECT), acquire data over a limited angle at any time, with full projections obtained by rotation of the detectors. In this paper, an approach is proposed for processing data from these systems, applicable to either PET or SPECT. A method of interpolation, based on overlapped parabolas, is used to obtain an estimate of the total counts in each pixel of the projections for each required frame-interval, which is the total time to acquire a single complete set of projections necessary for reconstruction. The resultant projections are reconstructed using traditional filtered backprojection (FBP) and tracer kinetic parameters are estimated using a method which relies on counts integrated over the frame-interval rather than instantaneous values. Simulated data were used to illustrate the technique's capabilities with noise levels typical of those encountered in either PET or SPECT. Dynamic datasets were constructed, based on kinetic parameters for fluoro-deoxy-glucose (FDG) and use of either a full ring detector or rotating detector acquisition. For the rotating detector, use of the interpolation scheme provided reconstructed dynamic images with reduced artefacts compared to unprocessed data or use of linear interpolation. Estimates for the metabolic rate of glucose had similar bias to those obtained from a full ring detector.