Epidermal growth factor as a biologic switch in hair growth cycle

The hair growth cycle consists of three stages known as the anagen (growing), catagen (involution), and telogen (resting) phases. This cyclical growth of hair is regulated by a diversity of growth factors. Although normal expression of both epidermal growth factor and its receptor (EGFR) in the outer root sheath is down-regulated with the completion of follicular growth, here we show that continuous expression of epidermal growth factor in hair follicles of transgenic mice arrested follicular development at the final stage of morphogenesis. Data from immunoprecipitation and immunoblotting showed that epidermal growth factor signals through EGFR/ErbB2 heterodimers in skin. Furthermore, topical application of tyrphostin AG1478 or AG825, specific inhibitors of EGFR and ErbB2, respectively, completely inhibited new hair growth in wild type mice but not in transgenic mice. When the transgenic mice were crossed with waved-2 mice, which possess a lower kinase activity of EGFR, the hair phenotype was rescued in the offspring. Taken together, these data suggest that EGFR signaling is indispensable for the initiation of hair growth. On the other hand, continuous expression of epidermal growth factor prevents entry into the catagen phase. We propose that epidermal growth factor functions as a biologic switch that is turned on and off in hair follicles at the beginning and end of the anagen phase of the hair cycle, guarding the entry to and exit from the anagen phase.postprin

Children's Preferential Modes of Spatial Communication

A group of lower primary children (age from 8-9 years old) was given a task to present spatial information to communicate with their peers about wayfinding to their school from the nearby mass transit railway station. The children were left with their own preferential choice to decide what mode of spatial communication was used to do the task. Different frameworks of cartographic analysis were used to understand the mapping quality of such spatial communication if children opted to draw map to show the spatial information. Selected children from distinctive categories were interviewed to further illuminate their spatial consideration when drawing the map to complete the task. The outcome of this study is hoped to provide insight to teachers the venue to understand their children better in terms of their giftedness in spatial and visual ability. Such understanding enables teachers to better prepare for meaningful and effective teaching in spatial related topics and issues.published_or_final_versio

Effects of chelators (desferal, deferiprone & deferaairox) on the growth of klebsiella and aeromonas isolated from transfusion dependent thalassemia patients

Poster Presentation (Doctor’s Session)Infection is among the leading causes of death for thalassemia major patients. The known predisposing factors of infection include prior splenectomy, iron overload and use of iron chelator such as desferal (desferrioxamine). While encapsulated organisms frequently found in splenectomized patients were readily controlled by prophylactic vaccination and vigilant antibiotic treatment, ferrophilic organisms such as Yersinia and Klebsiella remains common among Thalassemic patients. The inductive iron overloaded environment favours the growth of these organisms but their growth is also affected by the environment temperature. For example, Yersinia infection is more prevalent in temperate regions and Klebsiella infection is commonly found in subtropical areas. Furthermore, the use of iron chelator in the form of desferal further aggravates the risk of Yersinia infection. It is because the iron membrane transport protein siderophore found in desferal can be adopted by the bacteria for iron acquisition. However, oral chelators such as deferiprone do not enhance growth of Yersinia in vitro or in vivo. In order to find out whether such observation can be extended to Klebsiella and Aeromona infection, in vitro culture assay using Klebsiella pneumoniae and Aeromonas hydrophila obtained directly from our transfusion dependent thalassaemic patients were performed. The growth rates of the bacteria under iron rich, iron poor with or without different chelators were assessed. The growth rates were analyzed by both: (1) optic density of bacterial broth; and (2) colony count by bacterial agar plate. We found that the growth of Klebsiella was marginally enhanced by desferal in vitro when compared to Yersinia. Such unfavourable effect was not found in either deferiprone or deferasirox in vitro. On the other hand, the growth of Aeromonas was not affected by the presence of any of the 3 chelators. Therefore, we suggested that factors other than desferal may account for the increase prevalence of Klebsiella and Aeromonas infection among Asian thalassemic patients. It also suggests that oral chelators are safe for thalassemic patients during febrile illness. Unlike desferal, withholding iron chelator during infectious period may not be mandatory. But care has to be exercised especially for patients on deferiprone, since neutropenia has to be ruled out during febrile illness. This project was supported by the Children's Thalassaemia Foundationspublished_or_final_versio

Microsatellite instability and mismatch repair gene mutations are common in young colorectal cancer patients in Hong Kong

Conference Theme: Challenges to Specialists in the 21st centurypublished_or_final_versio

Carriers in Cell-Based Therapies for Neurological Disorders

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In utero pleuro-amniotic shunting in fetuses with chylothorax

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A contact cavity-biased method for grand canonical Monte Carlo simulations

A modification of the cavity-biased grand canonical Monte Carlo (GCMC) proposed by Mezei is introduced here. Instead of on a fixed grid, test points of cavities are generated at the contact positions around the centers of existing particles. The increase in the probability or bias of finding a cavity is related to the radial distribution function and can hence be corrected. With this new cavity-biased implementation, an improved convergence to equihbrium is demonstrated and higher densities can be attained. Comparisons with the standard GCMC method, and the original cavity-biased scheme of Mezei are made. © 1994 American Institute of Physics.published_or_final_versio

Use of FBG optical sensors for structural health monitoring: Practical application

This paper describes the development of FBG Optical sensors for their practical application on structural health monitoring. The sensors were installed on the Tsing Ma Bridge for a trial run. The results using FBG sensors were in excellent agreement with those acquired by the bridge WASHMS

The use of variable pulse width frequency double Neodymium: YAG 532 nm laser in the treatment of port wine stain in Chinese

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Can the Hospital Anxiety and Depression (HAD) Scale be used on Chinese elderly in general practice?

A study was carried out in a general practice in Hong Kong to find out if the Hospital Anxiety and Depression (HAD) Scale could be used to detect psychological problems in Chinese elderly. The HAD Scale was translated into Cantonese and administered by an interviewer to 298 Chinese aged 60 or above before their doctor consultations. The acceptance rate of the Scale was 96% and each interview took only 5-10 min to complete. All 298 elderly understood and completed the HAD Scale. Validation of the results of the HAD Scale by the Clinical Interview Schedule (CIS) was done on a random sample of 100 elderly. Relative operating characteristic (ROC) analysis showed that the optimal cut-off points of the HAD Scale was a depression score of 6 and an anxiety score of 3. The sensitivity was 80%, specificity was 90%, OMR (overall misclassification rate) was 12%, positive predictive value was 67% and negative predictive value was 95%. Thirty-six per cent of the,elderly had scores above these cut-off points. More females than males had high anxiety scores. Nearly half of those with positive HAD scores were not known to have any psychological illness. The HAD Scale has great potential to be used as a screening instrument for psychological illnesses in Cantonese-speaking Chinese elderly all over the world.postprin