Atmospheric radon in Hong Kong

For the first time in Hong Kong, atmospheric radon concentration was continuously monitored between November 2007 and October 2008. This paper presents the results obtained during the 12-month period. The annual mean atmospheric radon concentration in Hong Kong was found to be 9.3 Bqm(-3) which was close to the level at neighbouring places like Guangdong and Taiwan. An estimation of the dose arising from atmospheric radon to the Hong Kong population was made. The meteorological effects on the variation of atmospheric radon concentration were discussed. It was found that the origin of the airmass and stability of the local atmosphere played vital roles in the seasonal and diurnal variations respectively, whereas precipitation caused abrupt changes in rainy days. An attempt was also made to find out the contribution of atmospheric radon to the ambient gamma dose rate.

Transport and metabolism of the antitumour drug candidate 2'-benzoyloxycinnamaldehyde in Caco-2 cells

The transport and metabolism of the antitumour drug candidate 2'-benzoyloxycinnamaldehyde (BCA) was characterized in Caco-2 cells. BCA disappeared rapidly from the donor side without being transported to the receiver side during its absorptive transport across Caco-2 cells. Its metabolites 2'-hydroxycinnamaldehyde (HCA) and o-coumaric acid (OCA) were formed in both the donor and the receiver sides. HCA, in a separate study, also disappeared rapidly from the donor side, mostly being converted to its oxidative metabolite OCA during its absorptive transport across Caco-2 cells. OCA was transported rapidly in the absorptive direction across Caco-2 cells with a P(app) of 25.4 +/- 1.0 x 10(-6) cm s(-1) (mean +/- standard deviation (SD), n = 3). OCA was fully recovered from both the donor and the receiver side throughout the time-course of this study. Formation of HCA from BCA was inhibited almost completely by bis(p-nitrophenyl)phosphate (BNPP), a selective inhibitor of carboxylesterases (CES), and phenylmethylsulfonyl fluoride (PMSF), a broad specificity inhibitor of esterases in Caco-2 cells, suggesting that this hydrolytic biotransformation was likely mediated predominantly by CES. Conversion of HCA to OCA was inhibited significantly by isovanillin, a selective inhibitor of aldehyde oxidase (AO). Inhibitors for xanthine oxidase (XO) and aldehyde dehydrogenase (ALDH), which are known to be involved in the oxidation of aldehydes to carboxylic acids, did not have a significant effect on the biotransformation of HCA to OCA in Caco-2 cells. In summary, the present work demonstrates that BCA is hydrolysed rapidly to HCA, followed by subsequent oxidation to OCA, in Caco-2 cells. The results provide a mechanistic understanding of the poor absorption and low bioavailability of BCA after oral administration.

Effects of oral magnesium supplementation on insulin sensitivity and blood pressure in normo-magnesemic nondiabetic overweight Korean adults

BACKGROUND AND AIM

Little is known about the effect of magnesium on insulin sensitivity and BP in healthy individuals. Therefore, we investigated whether magnesium could improve insulin sensitivity and blood pressure (BP) in normo-magnesemic nondiabetic overweight adults.

METHODS AND RESULTS

In a double-blinded, placebo-controlled, randomized trial, a total of 155 participants (BMI > or = 23 kg/m(2)) received either 12.3 mmol (300 mg) of elemental magnesium in the form of magnesium oxide (n=75) or placebo (n=80) each day for 12 weeks, constituting the intent-to-treat population. A repeated-measures ANOVA was used to evaluate the between-group changes in variables during the study. The baseline characteristics between the intervention and control groups were similar. There were no significant differences between the groups in the pattern of change of the homeostasis model assessment insulin resistance index, BP over time during the 12-week study. In subgroup analysis, magnesium supplementation (n=8, 27, and 24, respectively) lowered BP much more than placebo (n=16, 29, and 25, respectively) in those subjects whose systolic BP > or = 140 mmHg, diastolic BP 80-90 mmHg, and diastolic BP > or = 90 mmHg at the start of the study (P=0.016, 0.043, and 0.023, respectively); in comparison, those subjects whose initial BP reading was low at baseline did not show a change in BP. No significant adverse events related to magnesium supplementation were recorded.

CONCLUSIONS

These results suggested that magnesium supplementation does not reduce BP and enhance insulin sensitivity in normo-magnesemic nondiabetic overweight people. However, it appears that magnesium supplementation may lower BP in healthy adults with higher BP.

Evaluation of haemodynamic flow to the hip in patients with systemic lupus erythematosus

OBJECTIVE

One of the groups with high risk for osteonecrosis is patients with systemic lupus erythematosus (SLE). No predictive test, however, is known to detect osteonecrosis. The purpose of this study was to evaluate haemodynamic flow to the proximal femur in SLE patients.

METHODS

Twenty-two SLE patients without osteonecrosis were evaluated in comparison with 15 healthy controls. Medial and lateral circumflex arteries of 44 hips in the 22 SLE patients and 30 hips in the healthy controls were examined using ultrasound equipment with colour and power Doppler capability. Arterial pulsatility index (PI) and peak systolic velocity (PSV) were determined with neutral and internal rotation positions (stimulated ischaemia).

RESULTS

PSV was significantly increased in SLE patients compared to healthy controls in both the neutral position (70.6+/-40.4 vs. 46.9+/-19.3; p<0.001) and after internal rotation of the femoral head (74.8+/-42.3 vs. 49.9+/-19.9; p<0.001). PI was also higher in SLE patients than in healthy controls in both the neutral position (8.9+/-6.3 vs. 5.5+/-3.4; p<0.001) and after internal rotation (8.1+/-7.1 vs. 3.9+/-2.4; p<0.001).

CONCLUSION

PSV and PI of arteries to the femur head in SLE patients were significantly higher than in healthy controls.

Long-term follow-up after deferring angioplasty in asymptomatic patients with moderate noncritical in-stent restenosis

BACKGROUND

Many patients with in-stent restenosis (ISR) are angina-free, but the optimal treatment for these patients remains uncertain.

HYPOTHESIS

In cases with asymptomatic moderate noncritical ISR. deferral of the intervention may be safe and associated with favorable clinical outcome.

METHODS

We evaluated the long-term clinical outcome of asymptomatic patients (Group 1, n = 98) with moderate noncritical ISR (< 70% diameter stenosis) after intervention was deferred, and compared it with that of patients (Group 2, n = 655) without restenosis. After repeat angioplasty was deferred, all patients were treated medically and later underwent angioplasty only in the case of clinical recurrence.

RESULTS

Baseline characteristics were similar between the two groups. Clinical follow-up was available in all patients at 26.3+/-15.9 months. Twenty patients died during the follow-up: 1 in Group 1 and 19 in Group 2. Target lesion revascularization was performed in 3 patients in Group 1 and 11 patients in Group 2 during follow-up (p = NS), and new lesion revascularization in 2 patients in Group 1 and 27 patients in Group 2 (p = NS). Event-free survival rate (cardiac death, nonfatal myocardial infarction, repeat revascularization) was 86.7+/-6.1% in Group 1 and 84.8+/-2.2% in Group 2 at the end of follow-up (p = NS). Major adverse cardiac events were only associated with the presence of diabetic mellitus (hazards ratio 2.65, 95% confidence interval [CI] 1.48-4.73, p<0.01). The percentage of patients receiving antianginal medication was similar between the two groups at the end of the study (p = NS).

CONCLUSIONS

Asymptomatic patients with moderate noncritical ISR have a good prognosis and similar clinical outcome as those without ISR, suggesting that it may be safe to defer repeat angioplasty in these patients until angina recurrence.

Immediate and late clinical and angiographic outcomes after GFX coronary stenting: is high-pressure balloon dilatation necessary?

BACKGROUND

The GFX stent is a balloon-expandable stent made of sinusoidal element of stainless steel. The adjunct high-pressure balloon dilatations were usually recommended in routine stenting procedure.

HYPOTHESIS

The aim of this study was to evaluate the immediate and long-term clinical and angiographic outcomes and to investigate the necessity of high-pressure balloon dilatation during GFX stenting.

METHODS

In all, 172 consecutive patients underwent single 12 or 18 mm GFX stent implantation in 188 native coronary lesions. Two types of stenting technique were used: (1) stent size of a final stent-to-artery ratio of 1:1 (inflation pressure > 10 atm, high-pressure group), and (2) stent size of 0.5 mm bigger than reference vessel (inflation pressure < or = 10 atm, low-pressure group). The adjunct high-pressure balloon dilatations were performed only in cases of suboptimal results.

RESULTS

The adjunct high-pressure balloon dilatation was required in 11 of 83 lesions (13%) in the high-pressure group and in 7 of 105 lesions (7%) in the low-pressure group (p = 0.203). Procedural success rate was 100%. There were no significant differences of in-hospital and long-term clinical events between the two groups. The overall angiographic restenosis rate was 17.7%; 18.4% in the high-pressure group and 17.1% in the low-pressure group (p = 0.991).

CONCLUSIONS

The GFX stent is a safe and effective device with a high procedural success rate and favorable late clinical outcome for treatment of native coronary artery disease. Further randomized trials may be needed to compare stenting techniques in GFX stent implantation.

Rescue use of abciximab improves regional left ventricular function after early incomplete reperfusion in acute myocardial infarction

BACKGROUND

Abciximab was shown to have important beneficial effects beyond the maintenance of epicardial coronary artery patency. However, it remains uncertain whether abciximab may lead to a better functional outcome in patients with acute myocardial infarction (AMI) and with incomplete reperfusion after primary angioplasty (PA).

HYPOTHESIS

The study aimed to evaluate whether rescue use of abciximab may lead to a better functional outcome in such patients.

METHODS

The study included 25 patients with first AMI who met the following criteria: (1) total occlusion of the infarct-related artery, (2) PA within 12 h of symptom onset, (3) postprocedural diameter stenosis < 30%, and final Thrombolysis in Myocardial Infarction (TIMI) flow grade 2. Echocardiographic examination was performed before and on Days 7 and 30 after PA. The study population was divided into two groups: Group 1 (usual care, n = 13) and Group 2 (rescue use of abciximab, n = 12). Baseline characteristics were similar between the two groups.

RESULTS

Peak level of creatine kinase was higher in Group 1 than in Group 2 (5,800+/-2,700 vs. 3,800+/-2,000 U/I, p < 0.05). At 1 month follow-up, infarct zone wall motion score index (2.71+/-0.26 vs. 2.05+/-0.63, p < 0.01) and left ventricular (LV) volume indices were smaller in Group 2 than in Group 1, whereas LV ejection fraction was higher in Group 2 than in Group 1 (52.1+/-7.8 vs. 42.1+/-6.4, p < 0.01). At 1-month, abciximab was the only independent predictor of wall motion recovery index by multiple regression analysis.

CONCLUSIONS

Rescue use of abciximab may reduce the infarct size in patients with AMI and TIMI grade 2 flow after PA, which may improve the recovery of regional LV function.

Proteomic analysis of differential protein expression in atherosclerosis

Although recent studies have shown that several pro-inflammatory proteins can be used as biomarkers for atherosclerosis, the mechanism of atherogenesis is unclear and little information is available regarding proteins involved in development of the disease. Atherosclerotic tissue samples were collected from patients in order to identify the proteins involved in atherogenesis. The protein expression profile of atherosclerosis patients was analysed using two-dimensional electrophoresis-based proteomics. Thirty-nine proteins were detected that were differentially expressed in the atherosclerotic aorta compared with the normal aorta. Twenty-seven of these proteins were identified in the MS-FIT database. They are involved in a number of biological processes, including calcium-mediated processes, migration of vascular smooth muscle cells, matrix metalloproteinase activation and regulation of pro-inflammatory cytokines. Confirmation of differential protein expression was performed by Western blot analysis. Potential applications of the results include the identification and characterization of signalling pathways involved in atherogenesis, and further exploration of the role of selected identified proteins in atherosclerosis.

ABLE - assessment based learning

Over the past decade the Australian health care system has moved rapidly toward a greater emphasis on medical care being provided within the community. This trend can only continue as our population ages and levels of chronic and complex illness continue to rise. Primary care now includes: a higher proportion of general practitioners working in group practices supported by practice nurses and allied health professionals- both on site and in the community, increased patient presentations for chronic and complex disease - often compounded by mental health and social issues, and, more hospital in the home, early discharge and similar programmes enabling shared management of sicker patients in the community.

Gluteal compartment syndrome following abdominal aortic aneurysm repair: a case report

Compartment syndromes occur when the elevated tissue pressure within a confined limb's myofascial compartment exceeds capillary pressure, with subsequent neurovascular compromise. In order to reduce disability and the consequences of ensuring ischemia, it is essential for early recognition and intervention. This is more commonly recognized in the calf. We report an unusual case of gluteal compartment syndrome after abdominal aortic aneurysm (AAA) repair.

Assessing potential pathogenicity of avian influenza virus: current and experimental system

An avian influenza (AI) isolate can be classified as a high pathogenicity avian influenza (HPAI) virus based upon the results of the standard intravenous pathogenicity index test; molecular classification, which is derived by sequencing the hemagglutinin gene across the site coding for the cleavage site; or a combination. However, discordant results between the molecular classification and virulence for experimentally infected chickens have been observed with several H5 and H7 subtype AI viruses. Because the declaration of HPAI virus results in severe effects on trade for the entire country, the gap between the genetic and phenotypic markers is an important issue, and it requires us to reexamine what should be considered an HPAI virus by the Office International des Epizooties standards. To better understand and assess the true virulence of the virus, potential pathogenicity of H5 and H7 subtype AI virus isolates has been assessed by examining the plaquing efficiency of the virus in chicken embryo fibroblast cells, conducting 14-day-old embryo passage and selection system, and applying in vitro mutagenesis coupled with reverse genetics. The potential value of these complimentary methods in assessing potential pathogenicity of the AI virus is discussed.

Experimental study on the effect of SO2 on PCDD/F emissions: determination of the importance of gas-phase versus solid-phase reactions in PCDD/F formation

Cofiring coal in municipal solid waste incinerators (MSWls) has previously been reported to reduce polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/Fs) emissions due to increasing the flue gas SO2 concentration. The present study was focused on understanding the primary mechanism responsible for the suppressant effect of SO2 on total PCDD/F formation and toxic equivalent (TEQ) emissions. The addition of SO2, simulating the effect of coal addition on the flue gas composition, resulted in significant reductions in the TEQ emissions due to reactions involving SO2 in the postcombustion zone. However, emissions of total PCDDs/Fs, unlike the TEQ value, were dependent upon the Cl2 and SO2 injection temperatures due to increases in non-TEQ correlated isomers. The conversion of metal chlorides in the fly ash to sulfates, thus reducing the sites responsible for chlorination/oxidation reactions, was concluded to be the main suppressant mechanism; proposed reactions for copper and iron are presented. This mechanism was found to be independent of combustion conditions and could have prolonged effects on PCDD/F emissions from deposits formed with high flue gas S/Cl ratios.

Regulation of survivin expression by IGF-1/mTOR signaling

Survivin is a dual regulator of cell proliferation and cell viability overexpressed in most human tumors. Although strategies to lower survivin levels have been pursued for rational cancer therapy, the molecular circuitries controlling survivin expression in tumors have not been completely elucidated. Here, we show that stimulation with insulin-like growth factor-1 (IGF-1) results in increased survivin expression in prostate cancer cells. This response is independent of de novo gene transcription, changes in mRNA expression or modifications of survivin protein stability. Instead, IGF-1 induced persistence and translation of a pool of survivin mRNA, in a reaction abolished by the mTOR (mammalian target of rapamycin) inhibitor, rapamycin. Forced expression of the mTOR target p70S6K1 reproduced the increase in survivin expression in prostate cancer cells, whereas acute ablation of endogenous p70S6K1 by small interfering RNA downregulated survivin levels. Rapamycin, alone or in combination with suboptimal concentrations of taxol reduced survivin protein levels, and decreased viability of prostate cancer cells. Therefore, IGF-1/mTOR signaling elevates survivin in prostate cancer cells via rapid changes in mRNA translation. Antagonists of this pathway may be beneficial to lower an antiapoptotic threshold maintained by survivin in prostate cancer.

Isolation of a novel mycovirus OMIV in Pleurotus ostreatus and its detection using a triple antibody sandwich-ELISA

A novel mycovirus was isolated from a diseased mushroom, Pleurotus ostreatus, using a purification procedure involving polyethylene glycol (PEG)-NaCl precipitation, differential centrifugation, and equilibrium centrifugation in a CsCl gradient. The virion was a 43 nm isometric virus encapsulating double-stranded RNA (dsRNA) genome of 2.1, 2.0, 1.9, and 1.7 kbp with a coat protein (CP) of 58 kDa. The new mycovirus was named Oyster Mushroom Isometric Virus (OMIV). A triple antibody sandwich-ELISA (TAS-ELISA) system was constructed to detect OMIV in the mushroom using an anti-OMIV mouse monoclonal antibody and an anti-OMIV rabbit polyclonal serum. The TAS-ELISA system was sensitive enough to allow detection of OMIV in the mushroom with the naked eye. It detected successfully virus particles from 0.6 mg of diseased tissue as well as 0.4 microg/ml purified virus preparation.

Singular meshless method using double layer potentials for exterior acoustics

Time-harmonic exterior acoustic problems are solved by using a singular meshless method in this paper. It is well known that the source points cannot be located on the real boundary, when the method of fundamental solutions (MFS) is used due to the singularity of the adopted kernel functions. Hence, if the source points are right on the boundary the diagonal terms of the influence matrices cannot be derived. Herein we present an approach to obtain the diagonal terms of the influence matrices of the MFS for the numerical treatment of exterior acoustics. By using the regularization technique to regularize the singularity and hypersingularity of the proposed kernel functions, the source points can be located on the real boundary and therefore the diagonal terms of influence matrices are determined. We also maintain the prominent features of the MFS, that it is free from mesh, singularity, and numerical integration. The normal derivative of the fundamental solution of the Helmholtz equation is composed of a two-point function, which is one of the radial basis functions. The solution of the problem is expressed in terms of a double-layer potential representation on the physical boundary based on the potential theory. The solutions of three selected examples are used to compare with the results of the exact solution, conventional MFS, boundary element method, and Dirichlet-to-Neumann finite element method. Good numerical performance is demonstrated by close agreement with other solutions.

Avian influenza vaccination in North America: strategies and difficulties

Vaccination with high quality efficacious vaccines that are properly delivered can contribute to the control of avian influenza (AI) outbreaks when used as part of a comprehensive control programme that includes quarantines, animal movement controls, increased biosecurity, enhanced surveillance, and education. In North America both whole virus killed adjuvanted vaccines and fowlpox recombinant vaccines have been used to aid in the control of AI. The fowlpox recombinant vaccine is licensed in several countries including the United States (U.S.), but it has only been used in the field in Mexico and some Central American countries. The U.S., however, has considerable experience with the use of killed vaccines, primarily in turkeys. In the state of Minnesota in the 1980s and early 1990s, outbreaks of AI in range-reared turkeys were common, and vaccines were used successfully as part of a controlled marketing programme. More recently, several large layer flocks in Connecticut were vaccinated as an alternative to immediate depopulation after an H7N2 low pathogenic AI outbreak. The vaccinated flocks were intensively monitored for virus shed using sentinel birds, dead bird testing, and eventually some serological surveillance using a neuraminidase DIVA (differentiation of infected from vaccinated animal) approach. With these successes, vaccination is being considered as a valuable tool in comprehensive AI control strategies. Consideration for matching the vaccine to the field strain should also be considered to provide optimal protection including reduced shedding of virus. Antigenic drift of AI viruses after extended vaccination programmes has been observed in chickens, similar to what has been observed with human influenza viruses. Therefore, periodical evaluation of the vaccine to the field strain is necessary to maintain good protection from clinical disease and virus shedding.

Isolation and characterization of H3N2 influenza A virus from turkeys

Five 34-wk-old turkey breeder layer flocks in separate houses of 2550 birds each in a single farm in Ohio experienced a drop in egg production from late January to early February 2004. Tracheal swabs (n = 60), cloacal swabs (n = 50), and convalescent sera (n = 110) from the flocks were submitted to the laboratory for diagnostics. Virus isolation was attempted in specific-pathogen free embryonating chicken eggs and Vero and MDCK cells. Virus characterization was performed using agar gel immunodiffusion, the hemagglutination test, the hemagglutination inhibition test, the virus neutralization test, reverse transcription-polymerase chain reaction, sequencing, and phylogenetic analysis. A presumptive influenza virus was successfully propagated and isolated on the first passage in MDCK cells, but initially not in Vero cells or specific-pathogen free chicken embryos. After two passages in MDCK cells, it was possible to propagate the isolate in specific-pathogen free chicken embryos. Preliminary sequence analysis of the isolated virus confirmed that it was influenza A virus with almost 100% (235/236) identity with the matrix gene of a swine influenza A virus, A/Swine/Illinois/100084/01 (H1N2). However, it was not possible to subtype the virus using conventional serotyping methods. The results of genetic characterization of the isolated virus showed that it was the H3N2 subtype and was designated as A/Turkey/OH/313053/04 (H3N2). Phylogenetic analysis of the eight gene segments of the virus showed that A/Turkey/OH/313053/04 (H3N2) isolate was most closely related to the triple-reassortant H3N2 swine viruses [A/Swine/WI/14094/99 (H3N2)] that have been circulating among pigs in the United States since 1998, which contains gene segments from avian, swine, and human viruses. The A/Turkey/OH/313053/04 (H3N2) isolated from turkeys in this study was classified as a low pathogenic avian influenza A virus because it only caused a drop in egg production with minor other clinical signs and no mortality.

Expression of diphtheria toxin inStreptococcus mutansand induction of toxin-neutralizing antisera

The nontoxic full-length diphtheria toxin (DTX), fragment A (DTA), and fragment B (DTB) were each genetically fused to the major surface protein antigen P1 (SpaP) of Streptococcus mutans. Repeated attempts to express the recombinant DTX and DTB in the live oral vaccine candidate Streptococcus gordonii were unsuccessful, whereas DTA could be readily expressed in this bacterium. However, the recombinant DTX, DTB, and DTA could be expressed in the related oral bacterium S. mutans. Western blotting and enzyme-linked immunosorbant assay (ELISA) using anti-DTX and anti-P1 antibodies demonstrated the expression of the three fusion proteins in S. mutans. Mouse antisera raised against the recombinant S. mutans recognized the native DTX in Western immunoblotting. The antibodies raised against S. mutans expressing the recombinant DTX and DTA neutralized the cytotoxicity of the native toxin in a Vero cell assay, but the neutralization titers were relatively low. The potential of using S. gordonii as a live vaccine against diphtheria faces major challenges in the expression of DTX in this organism and in the induction of high-titer toxin-neutralizing antibodies.Key words: diphtheria toxin, Streptococcus mutans, Streptococcus gordonii.

Mutation analysis of hepatitis B virus promoters in chronically infected children

Hepatitis B viral (HBV) infection in early childhood is one of the leading causes of chronic hepatitis and liver cirrhosis that eventually lead to hepatic carcinoma. Despite the nationwide immunization programs to curtail the vertical transmission of HBV, childhood HBV infection through mothers is still occurring in Korea. As one of the efforts to understand the childhood HBV infection in Korea, four HBV promoter sequences in the sera of the chronically infected children were analyzed. Children harbored diverse viral variants as most of the chronically infected adult patients, but the deletion mutations were rare. The dominant viral sequences in the children were highly similar to the ones in the respective mothers, indicating that the maternal viruses were most likely transmitted to the children. The mutations in X, S1, S2/S promoters did not seem to show any correlation to the severity of the disease nor ages of the children. The mutations that showed some correlation to the severity of the disease were the mutations in C promoter, but the mutations did not seem to be vertically transmitted. Finally, the children with the elevated ALT/AST levels tended to have more child-specific variants suggesting that the accumulation of host-specific mutations might be associated with the development of clinical symptoms.