Sildenafil might impair maternal-fetal immunotolerance by suppressing myeloid-derived suppressor cells in mice.

Myeloid-derived suppressor cells (MDSCs) as an important population of immune cells were found to restrain T cell function, polarize T-helper cells (Th) 1/Th2 toward Th2 response and induce regulatory T cells (Tregs), therefore enhancing the immunotolerance during pregnancy. Sildenafil has been applied for poor endometrial quality in implantation failure patients. Nevertheless, investigations have shown that sildenafil could reduce MDSCs-dependent immunosuppression. Whether sildenafil affects embryo implantation by suppressing MDSCs? To address this question, using the mice model, we investigated the amounts of immune cells in peripheral blood and endometrial cells from control group (CG), sildenafil low-dose group (LDG) and high-dose group (HDG). We found that both treatment groups displayed a marked deficiency in polymorphonuclear (PMN)-MDSCs and Th2 from mice blood and endometrium as compared to these from CG. The frequency of Tregs in endometrium from HDG was lower than those from CG. Th1/Th2 ratio in both periphery and uterus from study groups showed a significant increase as compared to those from CG. By relevance analysis, we found that the level of Tregs positively correlated with the level of PMN-MDSCs, whereas the Th1/Th2 ratio negatively correlated with the frequency of PMN-MDSCs in uterus. Moreover, there was a positive relationship between the amount of blood PMN-MDSCs and endometrial PMN-MDSCs. These results suggest that we should carefully weigh the pros and cons of using sildenafil when applied to patients with poor endometrial receptivity.

Haplotype analysis encompassing HTT gene in Chinese patients with Huntington's disease.

BACKGROUND AND PURPOSE: Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder with varied prevalence in different populations, which may be associated with specific haplotypes. This study aimed to explore the haplotypes encompassing the HTT gene in the Chinese population. METHODS: A total of 406 individuals with HD and 59 normal relatives from 253 families with HD were enrolled. A total of 29 tag single nucleotide polymorphisms (tSNPs) were selected and genotyped for the haplotype analysis. RESULTS: In stage one, we used 18 tSNPs to replicate the distribution of three major haplogroups (A, B, C). We found that risk-associated haplogroup variants A1 and A2, enriched on Caucasian HD chromosomes, were totally absent from both Chinese HD and control chromosomes, and the distributions of haplogroups between HD and control chromosomes were similar. Therefore, in stage two, we used 29 tSNPs (including the18 tSNPs) to define new haplogroups (I, II, III) and found that haplogroup I accounted for 61.4% on HD chromosomes and 34.4% on control chromosomes, indicating that haplogroup I was enriched on Chinese HD chromosomes. CONCLUSIONS: This is the first haplotype analysis encompassing HTT in the Chinese population. The results contribute to explaining the low prevalence of HD in China and provide a better understanding of genetic diversity in the HTT region.

[Mouse models for human colorectal cancer with liver metastasis].

Objective: To established Apc(loxp/loxp)+Kras(LSL-G12D/-)+Smad4(loxp/loxp) transgenic mouse model that mimick the occurrence and development of human sporadic colorectal cancer(CRC) and its liver metastasis. Methods: C57BL/6-Apc(tm1Tyj)/J(Apc(loxP)), B6.129S4-Kras(tm4Tyj)/J(Kras(LSL-G12D)), 129S6-Smad4(tm2.1Cxd)/J(Smad4(loxP)) and C57BL/6J mice were crossed, and genotype with Apc(loxP/loxP)+Kras(LSL-G12D/-)and Apc(loxP/loxP)+Kras(LSL-G12D/-)+Smad4(loxP/loxP)were generated. Genotypes of the mice were identified by PCR and real-time quantitative PCR. The mice were divided into Apc(loxP/loxP)+Kras(LSL-G12D/-)+Smad4(loxP/loxP) group (n=20) and Apc(loxP/loxP)+Kras(LSL-G12D/-)group(n=24). Lentivirus expressing Cre enzyme and IRES-luciferase were injected into the submucosa of colon or rectum of the transgenic mice under colonoscopy. Intraabdominal injection of D-luciferase into mice every 4 weeks, imaging with small animal in vivo imaging system(IVIS). The tumor size, tumorigenesis rate and metastasis ratio were analyzed. At the end of the 20th week, the colorectal lesions and metastatic tissues of mice were stained with hematoxylin-eosin(HE) and the pathological changes were observed under microscope. Results: Apc(loxp/loxp)+Kras(LSL-G12D/-)+Smad4(loxp/loxp) and Apc(loxp/loxp)+Kras(LSL-G12D/-)transgenic mice were successfully bred. The colorectal stem cells of the transgenic mouse mutated leading tumor lesion and liver metastatic under the induction of Lentivirus(Cre-IRES-luciferase). The primary and metastatic foci of colorectal carcinoma and liver metastasis in mice were proved to be adenocarcinoma and liver metastatic carcinoma by histopathological examination. The primary tumor size inApc(loxP/loxP)+Kras(LSL-G12D/-)+Smad4(loxP/loxP) group and Apc(loxP/loxP)+Kras(LSL-G12D/-)group was(3.52±0.26) and(3.45±0.20)mm, respectively,without significant difference(t=0.872, P=0.388).The tumorigenesis rate was 70.0% and 50.0% respectively, and there was no significant difference between the two groups(χ(2)=0.440, P=0.507). The metastasis rate of two groups were 58.3% and 8.3%respectively(Fisher's exact test, P=0.027). Conclusions: In this study, the colorectal carcinogenesis and its spontaneously metastasis to the liver of CRC were induced by Lentivirus(Cre-IRES-luciferase) in our established transgenic mice,which successfully simulated the occurrence and development of human sporadic CRC and its liver metastasis.

AKT-GSK3ß Signaling Pathway Regulates Mitochondrial Dysfunction-Associated OPA1 Cleavage Contributing to Osteoblast Apoptosis: Preventative Effects of Hydroxytyrosol.

Oxidative stress (OS) induces osteoblast apoptosis, which plays a crucial role in the initiation and progression of osteoporosis. Although OS is closely associated with mitochondrial dysfunction, detailed mitochondrial mechanisms underlying OS-induced osteoblast apoptosis have not been thoroughly elucidated to date. In the present study, we found that mitochondrial abnormalities largely contributed to OS-induced osteoblast apoptosis, as evidenced by enhanced production of mitochondrial reactive oxygen species; considerable reduction in mitochondrial respiratory chain complex activity, mitochondrial membrane potential, and adenosine triphosphate production; abnormality in mitochondrial morphology; and alteration of mitochondrial dynamics. These mitochondrial abnormalities were primarily mediated by an imbalance in mitochondrial fusion and fission through a protein kinase B- (AKT-) glycogen synthase kinase 3ß- (GSK3ß-) optic atrophy 1- (OPA1-) dependent mechanism. Hydroxytyrosol (3,4-dihydroxyphenylethanol (HT)), an important compound in virgin olive oil, significantly prevented OS-induced osteoblast apoptosis. Specifically, HT inhibited OS-induced mitochondrial dysfunction by decreasing OPA1 cleavage and by increasing AKT and GSK3ß phosphorylation. Together, our results indicate that the AKT-GSK3ß signaling pathway regulates mitochondrial dysfunction-associated OPA1 cleavage, which may contribute to OS-induced osteoblast apoptosis. Moreover, our results suggest that HT could be an effective nutrient for preventing osteoporosis development.

Causes of ozone pollution in summer in Wuhan, Central China.

In August 2016, continuous measurements of volatile organic compounds (VOCs) and trace gases were conducted at an urban site in Wuhan. Four high-ozone (O3) days and twenty-seven non-high-O3 days were identified according to the China's National Standard Level II (∼100 ppbv). The occurrence of high-O3 days was accompanied by tropical cyclones. Much higher concentrations of VOCs and carbon monoxide (CO) were observed on the high-O3 days (p < 0.01). Model simulations revealed that vehicle exhausts were the dominant sources of VOCs, contributing 45.4 ±â€¯5.2% and 37.3 ±â€¯2.9% during high-O3 and non-high-O3 days, respectively. Both vehicle exhausts and stationary combustion made significantly larger contributions to O3 production on high-O3 days (p < 0.01). Analysis using a chemical transport model found that local photochemical formation accounted for 74.7 ±â€¯5.8% of the daytime O3, around twice the regional transport (32.2 ±â€¯5.4%), while the nighttime O3 was mainly attributable to regional transport (59.1 ±â€¯9.9%). The local O3 formation was generally limited by VOCs in urban Wuhan. To effectively control O3 pollution, the reduction ratio of VOCs to NOx concentrations should not be lower than 0.73, and the most efficient O3 abatement could be achieved by reducing VOCs from vehicle exhausts. This study contributes to the worldwide database of O3-VOC-NOx sensitivity research. Its findings will be helpful in formulating and implementing emission control strategies for dealing with O3 pollution in Wuhan.

New particle formation and growth at a suburban site and a background site in Hong Kong.

Atmospheric nanoparticles have great impacts on human health and global climate change. The number concentrations and size distributions of nanoparticles in the size range of 5.5-350.4 nm were detected at a background site and a suburban site in Hong Kong from summer to winter in 2011 and in autumn of 2013, respectively. Significantly higher particle number concentrations in all modes were observed at the suburban site (p < 0.05) during the sampling periods, possibly due to stronger primary emissions/regional transport and more intensive new particle formation (NPF). Particle number concentrations were much enhanced under northerly winds at both sites, resulting from regional transport of Aitken and accumulation mode particles, enhanced local NPF and occasionally low condensation sink. NPF was mainly limited by the precursors of condensable vapors and oxidative capacity of the atmosphere at the background site and the suburban site, respectively. In most cases, the formation rate of 5.5 nm particles was a function of sulfuric acid vapor to the power of 1.32 ± 0.34 at the background site and 0.81 ± 0.31 at the suburban site, abiding by the cluster activation theory. However, ozonolysis of monoterpenes (particularly α-pinene) might also drive NPF, particularly in the afternoon. These reactions also contributed to the growth of nucleation mode particles, which was largely explained by sulfuric acid vapor (73.6 ± 10% at the background site and 60.4 ± 9.8% at the suburban site). In contrast, the oxidations of isoprene, ß-pinene and aromatics (particularly xylenes and trimethylbenzenes) were found to participate in the growth of Aitken mode particles.

Observation of SOA tracers at a mountainous site in Hong Kong: Chemical characteristics, origins and implication on particle growth.

Secondary organic aerosol (SOA) is an important constituent of airborne fine particles. PM2.5 (particles with aerodynamic diameters≤2.5µm) samples were collected at a mountainous site in Hong Kong in autumn of 2010, and analyzed for SOA tracers. Results indicated that the concentrations of isoprene SOA tracers (54.7±22.7ng/m3) and aromatics SOA tracers (2.1±1.6ng/m3) were on relatively high levels in Hong Kong. Secondary organic carbon (SOC) derived from isoprene, monoterpenes, sesquiterpenes and aromatics was estimated with the SOA tracer based approach, which constituted 0.35±0.15µg/m3 (40.6±5.7%), 0.20±0.03µg/m3 (30.4±5.5%), 0.05±0.02µg/m3 (5.6±1.7%) and 0.26±0.20µg/m3 (21.3±8.2%) of the total estimated SOC. Biogenic SOC (0.60±0.18µg/m3) dominated over anthropogenic SOC (0.26±0.20µg/m3) at this site. In addition to the total estimated SOC (17.8±4.6% of organic carbon (OC) in PM2.5), primary organic carbon (POC) emitted from biomass burning also accounted for a considerable proportion of OC (11.6±3.2%). Insight into the OC origins found that regional transport significantly (p<0.05) elevated SOC from 0.37±0.17 to 1.04±0.39µg/m3. Besides, SOC load could also increase significantly if there was influence from local ship emission. Biomass burning related POC in regional air masses (0.81±0.24µg/m3) was also higher (p<0.05) than that in samples affected by local air (0.29±0.35µg/m3). Evidences indicated that SOA formation was closely related to new particle formation and the growth of nucleation mode particles, while biomass burning was responsible for some particle burst events in Hong Kong. This is the first SOA study in afforested areas of Hong Kong.

Tropospheric volatile organic compounds in China.

Photochemical smog, characterized by high concentrations of ozone (O3) and fine particles (PM2.5) in the atmosphere, has become one of the top environmental concerns in China. Volatile organic compounds (VOCs), one of the key precursors of O3 and secondary organic aerosol (SOA) (an important component of PM2.5), have a critical influence on atmospheric chemistry and subsequently affect regional and global climate. Thus, VOCs have been extensively studied in many cities and regions in China, especially in the North China Plain, the Yangtze River Delta and the Pearl River Delta regions where photochemical smog pollution has become increasingly worse over recent decades. This paper reviews the main studies conducted in China on the characteristics and sources of VOCs, their relationship with O3 and SOA, and their removal technology. This paper also provides an integrated literature review on the formulation and implementation of effective control strategies of VOCs and photochemical smog, as well as suggestions for future directions of VOCs study in China.

Expression and effect of serum interleukin-24 level on bone marrow mononuclear cells in children with acute leukemia.

To investigate the expression of interleukin-24 (IL-24) in the children with acute leukemia (AL) and its effect on the apoptosis of bone marrow mononuclear cells (BMMNCs) in vitro. Four groups were assessed: acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), non-leukemia, and healthy groups, 20 children in each group. ELISA was used to measure IL-24 serum level. The bone marrow was taken from patients and controls. BMMNCs were isolated and the DNA was analyzed by glucose electrophoresis. Flow cytometry was used to determine BMMNC apoptosis. The serum level of IL-24 in the ALL and AML groups were significantly higher than in the other two groups. There was no statistical difference between ALL and AML groups, either between non-leukemia and healthy groups. BMMNCs were exposed to IL-24 for 48 h, and the apoptotic rate of the group treated with 50 ng/ml IL-24 was obviously higher than that of control group (0 ng/mL). The serum IL-24 level of AL children decreased comparing to non-leukemia and healthy children, indicating that IL-24 can induce BMMNCs apoptosis of AL children in vitro.

Effects of docetaxel plus three-dimensional conformal radiation therapy on microvessel density and apoptosis expression in local advanced squamous non-small-cell lung cancer.

We examined the effects of weekly single-agent docetaxel plus three-dimensional conformal radiation therapy (3D-CRT) on apoptotic index (AI) and microvessel density (MVD) in local advanced non-small-cell lung squamous cancer patients and analyzed the correlation of MVD, AI, and 50% tumor shrinkage time (T0.5) The molecular mechanism of docetaxel radiosensitization was investigated. Sixty untreated patients with stage IIIA or IIIB lung squamous cancer were enrolled and randomly divided into two groups: observation (N = 30; 3D-CRT + docetaxel + adjuvant chemotherapy) and control (N = 30; 3D-CRT + adjuvant chemotherapy). From day 1 radiotherapy, the observation group received intravenous docetaxel (36 mg/m(2)) once weekly for 6 weeks. Post-radiotherapy, chemotherapy of docetaxel combined with cisplatin lasted 4-6 cycles in both groups. Before radiotherapy and within 24 h after radiotherapy (20 Gy), bronchoscopic biopsy was performed twice at the same site. To analyze the MVD of tumor specimens with immunohistochemical staining . The AI of lung cancer cells was assessed with TUNEL assay, T0.5 values were calculated. The observation group had significantly lower MVD than the control group (P < 0.05). AI significantly increased before and after treatment in the observation group compared with the control group (P < 0.05). The decreased MVD values negatively correlated with T0.5 values (r = -0.624, P < 0.05), whereas the increased AI values did not correlate with the T0.5 values. Docetaxel radiosensitization may occur by decrease in MVD and increase in AI values. Weekly single-agent docetaxel plus 3D-CRT can improve prognosis and quality of life in local advanced non-small-cell lung squamous cancer patients.

First Report of Myrothecium roridum Causing Leaf Spot of Anubias barteri var. nana in Mainland China.

Anubias barteri var. nana (belonging to family Araceae) is one of the most popular ornamental plants for aquaria. It has slow growth and small attractive ornamental leaves. It originated from West Africa, was first described in 1860 by Heinrich Wilhelm Schott (1), and is now commercially planted widely in southern China. A new disease of A. barteri var. nana was observed on leaves. Approximately 30% of the plants in an ornamental nursery in Baiyun district, Gaungzhou, China (113°22'45.15″ E, 23°23'41.15″ N) in July 2013 were found to be infected. The pathogen caused necrotic spots that progressed to form holes on leaves of the infected plants, negatively affecting their ornamental market value. Eventually the diseased plant died. White fungal fruiting bodies and black sporodochia were observed on the surfaces of the symptomatic leaves. A single-spore isolate (myr5) was obtained from the concentric lesions and cultured on potato dextrose agar (PDA). The floccose fungal colonies were white to buff, and black conidiomata were often visible on the surface after 25 days of incubation. The conidia had rounded ends and the average size of conidia was 5.98 ± 0.15 × 2.24 ± 0.08 µm. The rDNA internal transcribed spacer (ITS) region of isolate myr5 was amplified by PCR using ITS1 and ITS4 primer pairs. The amplified product was sequenced and deposited in GenBank (Accession No. KJ572115) and showed 99% identity to Myrothecium roridum isolates BBA 71015 (AJ302001) and BBA 67679 (AJ301995) (unpublished), and 100% identity to the isolate myr2-2 from Dieffenbachia picta 'Camilla' in Taiwan (2). On the basis of morphological and molecular characterization, the fungus causing leaf spot on A. barteri var. nana plants was identified as M. roridum Tode ex Fr (2,3). To confirm the etiology of the disease, Koch's postulates was performed in a greenhouse (28 ± 2°C) using 3-day-old cultures of isolate myr5 and fungal spore suspensions of 1 × 105 conidia ml-1 containing 0.05% of Tween 20. Sixteen healthy leaves, two each from eight plants, were infiltrated on two different parts close to the midribs with 100 µl of the fungal spore using needleless syringes. Water infiltration was used as the control treatment. Water-soaked brown lesions appeared on leaves 7 days after inoculation, followed by the development of dark concentric rings within the necrotic areas on the surface of the inoculated leaves after 15 days of incubation. These symptoms were similar to those in the naturally infected aquarium plants. No symptoms were observed on any of the water micro-infiltrated plants. The fungus was re-isolated from the inoculated plants, but not from control plants. To our knowledge, this is the first report of Myrothecium leaf spot caused by M. roridum on A. barteri var. nana in mainland China. References: (1) W. Crusio. Primitiae Africanae XII 79 (14):1-48, 1979. (2) C. F. Hong et al. Plant Dis. 97:1253, 2013. (3) M. Tulloch. Mycol. Pap. 130:1-42, 1972.

Photochemical trajectory modeling of ozone concentrations in Hong Kong.

In this study, tropical cyclones over the East and South China Seas were found to be the most predominant weather conditions associated with the occurrence of high ozone (O3) episodes in Hong Kong in 2005-2009. A photochemical trajectory model coupled with Master Chemical Mechanism (MCM) was adapted to simulate the O3 concentrations during two O3 pollution episodes. The results agreed well with the observed data. A representative backward air mass trajectory was used to determine the contribution of each volatile organic compound (VOC) to the O3 levels. After taking into account both reactivity and mass emission of each VOC, 10 species were found to be the key O3 precursors in Hong Kong. Further analysis identified solvent related products accounting for 70% of the modeled O3 concentration in Hong Kong. The results highlight the importance of considering together reactivity and source sector emissions in developing targeted VOC reduction for O3 abatement strategies.

Establishing a conceptual model for photochemical ozone pollution in subtropical Hong Kong.

Photochemical ozone (O3) formation is related to its precursors and meteorological conditions. A conceptual model of O3 air pollution is developed based on the analysis of data obtained at Tung Chung (TC) in Hong Kong. By comparing meteorological parameters between O3 and non-O3 episode days, it was found that high temperatures, strong solar radiation, low wind speeds and relative humidity, northeasterly and/or northwesterly prevailing winds were favorable for the O3 formation, while tropical cyclones were most conducive to the occurrence of O3 episodes. Backward trajectories simulation and graphical illustration of O3 pollution suggested that super-regional (i.e. central and eastern China) and regional (i.e. Pearl River Delta, southern China) transport was another factor that contributed to high O3 levels in Hong Kong. The photochemical O3 formation, generally VOC-limited in Hong Kong, was controlled by a small number of volatile organic compounds (VOCs). Furthermore, the positive matrix factorization (PMF) simulation suggested that solvent usage and vehicular emissions are the major contributors to ambient VOCs in Hong Kong. Finally, this paper presents recommendations for further O3 research and implementation of O3 control strategies.

Effects of hepatitis B virus precore and basal core promoter mutations on the expression of viral antigens: genotype B vs C.

Hepatitis B virus (HBV) genotypes/mutants are known to affect natural outcomes. The virologic differences among HBV genotype, precore and basal core promoter (BCP) mutations were investigated. HBV strains were isolated from 18 hepatitis B e antigen (HBeAg)-positive patients (nine genotype B and nine genotype C). All had precore and BCP wild-type sequences. After cloning of full-length HBV genome, the effects of viral genotype, precore and BCP mutations singly or additively on the expression of viral DNA and antigens were investigated by mutagenesis and transfection assays in Huh7 cells. Significant findings included the following: (i) expression of intracellular core protein increased when precore or BCP mutation was introduced in genotype C strains; (ii) expression of intracellular surface protein was lower in genotype C precore wild-type strain compared with genotype B; (iii) precore mutation was associated with a lower extracellular expression level of HBV DNA; (iv) secretion of hepatitis B surface antigen in genotype C was lower than that in genotype B; and (v) secretion of HBeAg in genotype B was lower than that in genotype C. No additive effect was observed by combining precore and BCP mutations. Hence, HBV genotype and precore/BCP mutations correlate with intrahepatic expression of viral antigens in vitro.

Sources of ambient volatile organic compounds and their contributions to photochemical ozone formation at a site in the Pearl River Delta, southern China.

The Positive Matrix Factorization (PMF) receptor model and the Observation Based Model (OBM) were combined to analyze volatile organic compound (VOC) data collected at a suburban site (WQS) in the PRD region. The purposes are to estimate the VOC source apportionment and investigate the contributions of these sources and species of these sources to the O(3) formation in PRD. Ten VOC sources were identified. We further applied the PMF-extracted concentrations of these 10 sources into the OBM and found "solvent usage 1", "diesel vehicular emissions" and "biomass/biofuel burning" contributed most to the O(3) formation at WQS. Among these three sources, higher Relative Incremental Reactivity (RIR)-weighted values of ethene, toluene and m/p-xylene indicated that they were mainly responsible for local O(3) formation in the region. Sensitivity analysis revealed that the sources of "diesel vehicular emissions", "biomass/biofuel burning" and "solvent usage 1" had low uncertainties whereas "gasoline evaporation" showed the highest uncertainty.

Post-partum weight retention in women in Asia: a systematic review.

Obesity is a health issue for people in Asia, and many studies support that childbearing may contribute to women's obesity. However, most studies of post-partum weight retention (PWR) focus on Western countries. This paper aimed to review recent data on PWR and discuss the related factors of PWR for women in Asia. Three electronic databases - MEDLINE, CINAHL and PsycINFO - were searched for data from January 1990 to August 2010. Twelve studies were identified as containing information related to PWR. Chinese, Taiwanese and Korean women tend to have higher gestational weight gain and PWR than women in other Asian countries in this review. The average reported gestational weight gain in these studies ranged from 8.3 kg to 18.0 kg, and the average weight retention at 6 months post partum in various countries ranged from 1.56 kg to 4.1 kg. Gestational weight gain had a positive effect on PWR, but there were no consistent conclusions for other factors. Only a few psychosocial and behavioural factors have been studied. Moreover, no one has assessed changes in waist circumference and waist-to-hip ratio for measuring central obesity and ensuring risk of chronic disease. Focusing on changes in maternal weight and body composition, and considering the impact of psychological and behavioural factors are suggested for future studies in Asia.

Which emission sources are responsible for the volatile organic compounds in the atmosphere of Pearl River Delta?

A field measurement study of volatile organic compounds (VOCs) was simultaneously carried out in October-December 2007 at an inland Pearl River Delta (PRD) site and a Hong Kong urban site. A receptor model i.e. positive matrix factorization (PMF) was applied to the data for the apportionment of pollution sources in the region. Five and six sources were identified in Hong Kong and the inland PRD region, respectively. The major sources identified in the region were vehicular emissions, solvent use and biomass burning, whereas extra sources found in inland PRD included liquefied petroleum gas and gasoline evaporation. In Hong Kong, the vehicular emissions made the most significant contribution to ambient VOCs (48 ± 4%), followed by solvent use (43 ± 2%) and biomass burning (9 ± 2%). In inland PRD, the largest contributor to ambient VOCs was solvent use (46 ± 1%), and vehicular emissions contributed 26 ± 1% to ambient VOCs. The percentage contribution of vehicular emission in Hong Kong in 2007 is close to that obtained in 2001-2003, whereas in inland PRD the contribution of solvent use to ambient VOCs in 2007 was at the upper range of the results obtained in previous studies and twice the 2006 PRD emission inventory. The findings advance our knowledge of ozone precursors in the PRD region.

The clinical significance of occult hepatitis B transfusion in Taiwan--a look-back study.

OBJECTIVES: A look-back study was conducted to determine the clinical significance of occult hepatitis B virus (HBV) blood transfusion in an HBV hyperendemic area. AIM: To improve the blood transfusion safety. BACKGROUND: Occult HBV is transmissible through blood transfusion in HBV-naÏve recipients. However, its impact on recipients with prevalent HBV infection in HBV hyperendemic areas is unclear. METHODS/MATERIALS: In 2006, 12 occult HBV blood donors were found from 10 824 repository samples by nucleic acid testing. The 74 corresponding recipients were identified and their pre- and post-transfusion clinical information was gathered, and the living recipients were recalled for follow-up. From the available archival sera, the HBV DNA was examined and sub-genomic sequences between paired donor and recipient were compared using polymerase chain reaction-based assays. RESULTS: Among the 74 recipients, 18 were still alive and 12 returned to our clinic. From the available serological profiles, 76% of recipients had ongoing or recovered HBV infection before transfusion. Only 24 recipients had available post-transfusion serological profiles and none seroconverted to be hepatitis B surface antigen (HBsAg) positive. Moreover, except for the prior HBsAg carriers, the recipients' HBV DNA levels after transfusion were low (<20 IU/mL). One recipient had identical HBV surface gene sub-genomic sequence (384 nucleotides) to his donor. After transfusion, no recipient developed post-transfusion hepatitis (PTH) and the clinical outcome was good. CONCLUSION: In HBV hyperendemic areas, occult hepatitis B transfusion might not lead to HBsAg carriage or PTH. The risk of transfusion-transmitted HBV infection was probably lower than that in non-endemic areas because most recipients had already experienced HBV infection.

Formaldehyde and volatile organic compounds in Hong Kong homes: concentrations and impact factors.

UNLABELLED: This paper presents formaldehyde and volatile organic compounds (VOC) concentrations, potential sources and impact factors in 100 homes. The 24-h average formaldehyde concentration in 37 homes exceeded the good class of the Hong Kong Indoor Air Quality Objectives (HKIAQO), whereas the total VOCs concentration in all homes was lower than the HKIAQO. Compared to other East Asian cities, indoor formaldehyde and styrene in Hong Kong was the highest, reflecting that the homes in Hong Kong were more affected by household products and materials. The formaldehyde concentration in newly built apartments was significantly higher than that in old buildings, whereas no relationship between the concentration and the building age was found for VOCs. There was no difference for formaldehyde and toluene between smoking and non-smoking homes, suggesting that cigarette smoking was not the major source of these two species. Homes of a couple with a child had higher formaldehyde and acetic acid concentrations, while homes with more than three people had higher concentrations of 1-butanol, heptane and d-limonene. When shoes were inside the homes, heptane, acetic acid, nonane and styrene concentrations were statistically higher than that when shoes were out of the homes. Furthermore, higher levels of 1,2,4-trimethylbenzene, styrene, nonane and heptane were found in gas-use families rather than in electricity-use homes. PRACTICAL IMPLICATIONS: Long-term exposure to formaldehyde and volatile organic compounds (VOC) in indoor environments may cause a number of adverse health effects such as asthma, dizziness, respiratory and lung diseases, and even cancers. Therefore, it is critical to minimize indoor air pollution caused by formaldehyde and VOCs. The findings obtained in this study would significantly enhance our understanding on the levels, emission sources and factors which affect indoor concentrations of formaldehyde and VOCs. The results can help housing designers, builders, home residents, and housing department of the government to improve indoor air quality (IAQ) by means of appropriate building materials, clean household products and proper life styles. It can also help policy makers reconcile the IAQ objectives and guidelines.