Outside of his illustrious medical career, Dr Chung is also a keen advocate of first-aid promotion. Since 1991, he has been working for the Hong Kong St John Ambulance and is currently the Director ...of the Association, where he takes up administrative, course development, and teaching duties. Today, St John Ambulance continues to regularly hold AED courses for the public, and knowledge of proper AED usage is a prerequisite for brigade members of the organisation. Since 2006, Dr Chung has led mass cardiopulmonary resuscitation (CPR) training programmes in different areas of Hong Kong. ...he implemented and led a pilot project of free CPR training for taxi drivers in 2011.
Despite the fact that integrin-mediated lymphocyte adhesion is a crucial event for an appropriate immune response, little is known about the mechanisms that control the adhesion and deadhesion ...processes generated by the engagement of CD99 between various types of immune cells. Here we report that the CD99 gene encodes two distinct proteins with opposite functions in the LFA-1/intercellular adhesion molecule 1 (ICAM-1)-mediated cell adhesion process. The two forms of the CD99 protein are produced by alternative splicing of the CD99 gene transcript. The major form induced homotypic adhesion of the human B lymphoblastoid cell line IM-9, whereas the minor, truncated form inhibited the adhesion process. Activation of the major form of CD99 with anti-CD99 monoclonal antibodies induced rapid aggregation of IM-9 cells, which was blocked by the addition of mAbs to LFA-1 or intracellular adhesion molecule 1. Overexpression of the minor truncated form of CD99 markedly down-regulated the expression of LFA-1. The two forms of CD99 are differentially expressed in most human cells tested and are highly conserved in monkey. Taken together, these observations suggest that the two forms of CD99 function in vivo in both positive and negative regulation of LFA-1-mediated adhesion of lymphocytes during an immune response.
In the study, a complex composed of alginate blended with a water-soluble chitosan (N,O-carboxymethyl chitosan, NOCC) was prepared to form microencapsulated beads by dropping aqueous alginate–NOCC ...into a Ca2+ solution. These microencapsulated beads were evaluated as a pH-sensitive system for delivery of a model protein drug (bovine serum albumin, BSA). The main advantage of this system is that all procedures used were performed in aqueous medium at neutral environment, which may preserve the bioactivity of protein drugs. The swelling characteristics of these hydrogel beads at distinct compositions as a function of pH values were investigated. It was found that the test beads with an alginate-to-NOCC weight ratio of 1:1 had a better swelling characteristic among all studied groups. With increasing the total concentration of alginate–NOCC, the effective crosslinking density of test beads increased significantly and a greater amount of drug was entrapped in the polymer chains (up to 77%). The swelling ratios of all test groups were approximately the same (∼3.0) at pH 1.2. At pH 7.4, with increasing the total concentration of alginate–NOCC, the swelling ratios of test beads increased significantly (20.0–40.0), due to a larger swelling force created by the electrostatic repulsion between the ionized acid groups (–COO−). It was shown that BSA was uniformly distributed in all test beads. At pH 1.2, retention of BSA in hydrogels may be improved by rinsing test beads with acetone (the amount of BSA released was below 15%). At pH 7.4, the amounts of BSA released increased significantly (∼80%) as compared to those released at pH 1.2. With increasing the total concentration of alginate–NOCC, the release of encapsulated proteins was slower. Thus, the calcium–alginate–NOCC beads with distinct total concentrations developed in the study may be used as a potential system for oral delivery of protein drugs to different regions of the intestinal tract.
A high cementitious content inportland cement concrete can cause early cracking of concrete. This study investigated the effects of minimized paste volume in concrete with the effects of portland ...limestone cement (PLC) and blended aggregates (BA). Based on the laboratory results and numerical modeling, the performance of pavement concrete with different paste volumes was evaluated. The paste volume of concrete could be reduced to 23.7% without affecting its strength and durability as evaluated by rapid chloride penetrability testing (RCPT) and surface resistivity (SR) tests. The paste volume of concrete with the BA technique could be further reduced to 22.6%. When the concrete mixtures were evaluated by using the critical stress analysis, their potential performance was noted to decrease as the paste volume decreased. The concrete mixtures with the BA technique were noted to have better potential performance as a pavement concrete. The concrete using PLC has comparable performance as that of the conventional concrete. Keywords: blended aggregates; minimized cement paste volume; pavement concrete; performance prediction; portland limestone cement (PLC); stress to strength ratio.
Atrial fibrillation is a highly prevalent arrhythmia and a major risk factor for stroke, heart failure and death. We conducted a genome-wide association study (GWAS) in individuals of European ...ancestry, including 6,707 with and 52,426 without atrial fibrillation. Six new atrial fibrillation susceptibility loci were identified and replicated in an additional sample of individuals of European ancestry, including 5,381 subjects with and 10,030 subjects without atrial fibrillation (P < 5 × 10(-8)). Four of the loci identified in Europeans were further replicated in silico in a GWAS of Japanese individuals, including 843 individuals with and 3,350 individuals without atrial fibrillation. The identified loci implicate candidate genes that encode transcription factors related to cardiopulmonary development, cardiac-expressed ion channels and cell signaling molecules.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The fission yeast
Schizosaccharomyces pombe contains two dithiol glutaredoxins (Grx1 and Grx2) and genes for three putative monothiol glutaredoxins (
grx3,
4, and
5). We investigated the expression, ...sub-cellular localization, and functions of the three monothiol glutaredoxins. Fluorescence microscopy revealed that Grx3 is targeted to nuclear rim and endoplasmic reticulum, Grx4 primarily to the nucleus, and Grx5 to mitochondria. Null mutation of
grx3 did not significantly affect growth and resistance against various oxidants, whereas
grx5 mutation caused slow growth and sensitivity toward oxidants such as hydrogen peroxide, paraquat, and diamide. The
grx2grx5 double mutation, deficient in all mitochondrial glutaredoxins, caused further retardation in growth and severe sensitivity toward all the oxidants tested. The
grx4 mutation was not viable, suggesting a critical role of Grx4 for the physiology of
S. pombe. Overproduction of Grx3 and Grx5, but not the truncated form of Grx5 without mitochondrial target sequence, severely retarded growth as Grx2 did, supporting the idea that Grx2, 3, and 5 are targeted to organellar compartments. Our results propose a distinct role for each glutaredoxin to maintain thiol redox balance, and hence the growth and stress resistance, of the fission yeast.
Abstract
This retrospective cohort study aims at determining whether baseline antral follicle count (AFC) and serum anti-Mullerian hormone (AMH) level in the index stimulation cycle predict ...live-birth outcome in subsequent frozen-thawed embryo transfer (FET) cycles. We studied 500 women undergoing the first IVF cycle who had embryo(s) cryopreserved. The main outcome measures were live-birth in the first FET cycle and cumulative live-birth in all the FETs combined after the same stimulation cycle. Our results showed that baseline AFC and AMH level on the day before ovarian stimulation showed significant correlation. In the first FET cycle, AFC and AMH level were significantly higher in subjects attaining live-birth in the first FET cycle or cumulative live-birth from all FETs than those who did not. Both AMH and AFC were insignificant predictors of live-birth in the first FET cycle or cumulative live-birth after adjusting for age. The areas under the ROC curves for AMH, AFC and age were 0.654, 0.625 and 0.628, respectively, for predicting cumulative live-birth. In conclusion, we reported for the first time that baseline AFC and AMH in the index stimulation cycle have only modest predictive performance on cumulative live-birth in subsequent FET cycles.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Nanoparticles based on stimuli-sensitive drug delivery have been extensively investigated for tumor targeting. Among them, pH-responsive drug targeting using pH-sensitive polymers has attracted ...attention because solid tumors have an acidic environment. A dextran-b-poly(L-histidine) (DexPHS) copolymer was synthesized and pH-responsive nanoparticles were fabricated for drug targeting.
A DexPHS block copolymer was synthesized by attaching the reductive end of dextran to the amine groups of poly(L-histidine). pH-responsive nanoparticles incorporating doxorubicin were fabricated and studied in HuCC-T1 cholangiocarcinoma cells. Synthesis of DexPHS was confirmed by 1H nuclear magnetic resonance spectroscopy, with specific peaks of dextran and PHS observed at 2-5 ppm and 7.4-9.0 ppm, respectively. DexPHS nanoparticles showed changes in particle size with pH sensitivity, ie, the size of the nanoparticles increased at an acidic pH and decreased at a basic pH. DexPHS block copolymer nanoparticles incorporating doxorubicin were prepared using the nanoprecipitation dialysis method. The doxorubicin release rate was increased at acidic pH compared with basic pH, indicating that DexPHS nanoparticles have pH-sensitive properties and that drug release can be controlled by variations in pH. The antitumor activity of DexPHS nanoparticles incorporating doxorubicin were studied using HuCC-T1 cholangiocarcinoma cells. Viability was decreased in cells treated with nanoparticles at acidic pH, whereas cell viability in response to treatment with doxorubicin did not vary according to changes of pH.
Our results indicated that DexPHS polymeric micelles are promising candidates for antitumor drug targeting.
Ultrawide-band tunable fiber ring lasers using 84.6-cm-long lanthanum-codoped bismuth-based erbium doped fiber and a narrow-band tunable microelectromechanical system filter are reported. The fiber ...ring lasers can be continuously tuned from 1520 to 1626 nm, covering both the C- and L-bands. The laser has two outputs; the high output power port exhibits better than 35-dB wavelength extinction ratio, and the second output has much lower power but exhibits a large extinction ratio of better than 60 dB.
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