VOC and IVOC emission features and inventory of motorcycles in China

How did the motorcycle emissions evolve during the economic development in China? To address data gaps, this study firstly measured the volatile organic compound (VOC) and intermediate-volatility organic compound (IVOC) emissions from motorcycles. The results confirmed that the emission control of motorcycles, especially small-displacement motorcycles, significantly lagged behind other gasoline-powered vehicles. For the China IV motorcycles, the average VOC and IVOC emission factors (EFs) were 2.74 and 7.78 times higher than the China V-VI light-duty gasoline vehicles, respectively. The notable high IVOC emissions were attributed to a dual influence from gasoline and lubricating oil. Furthermore, based on the complete EF dataset and economy-related activity data, a county-level emission inventory was developed in China. Motorcycle VOC and IVOC emissions changed from 2536.48 Gg and 197.19 Gg in 2006 to 594.21 Gg and 12.66 Gg in 2020, respectively. The absence of motorcycle IVOC emissions in the existed vehicular inventories led to an underestimation of up to 20%. Across the 15 years, the motorcycle VOC and IVOC emission hotspots were concentrated in the undeveloped regions, with the rural emissions reaching 5.81-10.14 times those of the urban emissions. This study provides the first-hand and close-to-realistic data to support motorcycle emission management and accurate air quality simulations.

Impact of spatial scales of control measures on the effectiveness of ozone pollution mitigation in eastern China

Ozone (O3) pollution is becoming the primary air pollution issue with the large decrease in fine particulate concentrations in eastern China. The development of widely recognized policies for controlling O3 pollution episodes is urgent. This study aims to provide actionable and comprehensive suggestions for O3 control policy development, with an emphasis on the precursor emission reductions. Here, we compared the impacts of different spatial scale reductions on a widespread O3 pollution episode in eastern China by a state-of-the-art regional air quality model. We find that region-scale joint control (in >30 cities) is much more effective than city-scale sporadic reduction in reducing O3 concentration. Sporadic controls only reduce the maximum daily 8-h average (MDA8) O3 by ∼1 μg/m3 in the controlled city, whereas regional controls lead to a MDA8 O3 decrease of ∼8 μg/m3 in the controlled region. In addition, the emission reduction effectiveness increased by 2.6 times from <5 cities to >30 cities. Continuous reductions have a cumulative effect on the decrease of MDA8 O3, showing the strongest effects within 24 h and diminishing after 48 h, which underscores the importance of reducing emissions 24 h prior to an episode. Moreover, the effect of control measures on MDA8 O3 varies spatially depending on the ratio of volatile organic compounds (VOCs) to nitrogen oxides (NOx) (VOCs/NOx). Both the reductions of VOC and NOx emissions have a positive effect on the decrease of MDA8 O3 in summer, but the effects of VOC reductions are 1.2 to 1.7 times higher than those of NOx reductions. The residential sector, due to its high VOCs/NOx emission ratio, exhibits the highest efficiency in the reduction of O3 concentrations. Our results highlight the importance of regional joint control and synergistic reduction of VOCs and NOx in eastern China.

Prevalence and influencing factors of depressive and anxiety symptoms among hospital-based healthcare workers during the surge period of the COVID-19 pandemic in the Chinese mainland: a multicenter cross-sectional study

BACKGROUND

From November 2022 to February 2023, the Chinese mainland experienced a surge in COVID-19 infection and hospitalization, and the hospital-based healthcare workers (HCWs) might suffer serious psychological crisis during this period. This study aims to assess the depressive and anxiety symptoms among HCWs during the surge of COVID-19 pandemic and to provide possible reference on protecting mental health of HCWs in future infectious disease outbreaks.

METHODS

A multicenter cross-sectional study was carried out among hospital-based HCWs in the Chinese mainland from 5 January to 9 February 2023. The PHQ-9 (nine-item Patient Health Questionnaire) and GAD-7 (seven-item Generalized Anxiety Disorder Questionnaire) were used to measure depressive and anxiety symptoms. Ordinal logistic regression analysis was performed to identify influencing factors.

RESULTS

A total of 6522 hospital-based HCWs in the Chinse mainland were included in this survey. The prevalence of depressive symptoms among the HCWs was 70.75%, and anxiety symptoms was 47.87%. The HCWs who perceived higher risk of COVID-19 infection and those who had higher work intensity were more likely to experience depressive and anxiety symptoms. Additionally, higher levels of mindfulness, resilience and perceived social support were negatively associated with depressive and anxiety symptoms.

CONCLUSION

This study revealed that a high proportion of HCWs in the Chinese mainland suffered from mental health disturbances during the surge of the COVID-19 pandemic. Resilience, mindfulness and perceived social support are important protective factors of HCWs' mental health. Tailored interventions, such as mindfulness practice, should be implemented to alleviate psychological symptoms of HCWs during the COVID-19 pandemic or other similar events in the future.

Determination of Urban Formaldehyde Emission Ratios in the Shanghai Megacity

We analyzed two data sets of atmospheric formaldehyde (FA) at an urban site in the Shanghai megacity during the summer of 2017 and the winter of 2017/18, with the primary objective of determining the emission ratio of formaldehyde versus carbon monoxide (CO). Through the photochemical age method and the minimum R squared (MRS) method, we derived the summer urban formaldehyde release ratios of 3.37 ppbv (ppmv of CO)-1 and 4.04 ppbv (ppmv of CO)-1, respectively. The error of both estimations is within ±20%, indicating the consistency of the results. We recognized the hourly minimum emission ratios determined from the MRS method to be indicative of actual formaldehyde emission ratios. Similarly, the emission ratio in winter is determined to be 2.10 ppbv (ppmv of CO)-1 utilizing the MRS method. The findings provide significant insights into the potential impact of motor vehicle exhaust on formaldehyde emissions in urban areas. This work demonstrates that the formaldehyde emission ratio determined by the MRS method can be used to represent the emissions of the freshest air mass. Formaldehyde photolysis contributed an average of 9% to the free radical primary reaction rate (P(ROx)) as a single chemical species during the daytime in summer, which was lower than the 11% recorded in winter. Formaldehyde emission reduction positively impacts local ozone production, so models describing ozone formation in Shanghai during summer need to reflect these emissions accurately. Evidence of the crucial catalytic role of formaldehyde in particulate matter formation has been confirmed by recent research. A potentially effective way to decrease the incidence of haze days in autumn and winter in the future is therefore to focus on reducing formaldehyde emissions.

[Human papillomavirus vaccination for men who have sex with men in China: demand and suggestions]

MSM are a high-risk population for HPV infection and related diseases. MSM can be effectively protected by quadrivalent and nine-valent HPV vaccines. This paper outlines the significance of providing HPV vaccination to MSM, summarizes the basis of HPV vaccination in MSM, and puts forward the following recommendations. First, China should expedite the development and approval of the HPV vaccine for male use. Second, HIV-positive MSM should vaccinate against HPV as soon as possible. Third, prioritize HPV vaccination for MSM individuals aged 26 or less. Fourth, for MSM aged over 26, catch-up vaccination or opportunistic vaccination should be provided when HPV vaccine resources are sufficient. Implementing this vaccination strategy can provide protection for the MSM and control the spread of sexually transmitted diseases.

Atmospheric gaseous aromatic hydrocarbons in eastern China based on mobile measurements: Spatial distribution, secondary formation potential and source apportionment

Monocyclic aromatic hydrocarbons (MAHs) and polycyclic aromatic hydrocarbons (PAHs) are both well known as hazardous air pollutants and also important anthropogenic precursors of tropospheric ozone (O₃) and secondary organic aerosols (SOA). In recent years, there have been intensive studies covering MAHs emission from various sources and their behavior under stimulated photochemical conditions. Yet in-situ measurements of PAHs presence and variations in ambient air are sparse. Herein we conducted large geometrical scale mobile measurements for 16 aromatic hydrocarbons (AHs, including 7 MAHs and 9 PAHs) in eastern China between October 27 and November 8, 2019. This unique dataset has allowed for some insights in terms of AHs concentration variations, accompanying chemical composition, source contributions and spatial distributions in eastern China. In general, AHs showed a clear concentration variability between the south and the north of the Yangtze River Delta (YRD). The concentrations of PAHs were approximately 9% of AHs, but contributed 23% of SOA formation potential. Source apportionment via positive matrix factorization (PMF) model revealed that industrial processes as the largest source (44%) of observed AHs, followed by solvent usage (21%), vehicle exhaust (19%), coal combustion (11%) and coking processes (6%). In the perspective of PAHs sources, coal combustion emissions were identified as the dominating factor of a share of 41%-52% in eastern China. Our findings complemented the simultaneously monitoring information of PAHs and MAHs in eastern China, revealed the importance of PAHs to SOA formation and highlighted the necessity of formulating strategies to reduce emissions from anthropogenic sources and reduce risks to human health.

Observation-based sources evolution of non-methane hydrocarbons (NMHCs) in a megacity of China

Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region.

Primary organic gas emissions in vehicle cold start events: Rates, compositions and temperature effects

Identification of air toxics emitted from light-duty gasoline vehicles (LDGVs) is expected to better protect human health. Here, the volatile organic compound (VOC) and intermediate VOC (IVOC) emissions in the high-emitted start stages were measured on a chassis dynamometer under normal and extreme temperatures for China 6 LDGVs. Low temperature enhanced the emission rates (ERs) of both VOCs and IVOCs. The VOC ERs were averaged 5.19 ± 2.74 times higher when the temperature dropped from 23 °C to 0 °C, and IVOCs were less sensitive to temperature change with an enlargement of 2.27 ± 0.19 times. Aromatics (46.75 ± 2.83%) and alkanes (18.46 ± 1.21%) dominated the cold start VOC emissions under normal temperature, which was quite different from hot running emission profiles. From the perspective of emission inventories, changes in the speciated composition of VOCs and IVOCs were less important than that in the actual magnitude of ERs under cold conditions. However, changes in the ERs and emission profiles were equally important at high temperatures. Furthermore, high time-resolved measurements revealed that low temperature enhanced both the emission peak and peak duration of fuel components and incomplete combustion products during cold start, while high temperature only increased the peak concentration of fuel components.

Multi-factor reconciliation of discrepancies in ozone-precursor sensitivity retrieved from observation- and emission-based models

Ground-level O₃ pollution has been continuously worsening in China despite gradual improvement in other major pollutant levels. Understanding the sensitivity of O₃ production to its precursors (OPS) is a prerequisite for formulating effective O₃ control measures, but this has been hampered by significant discrepancies in OPS produced by traditional identification approaches using observation-based models (OBM) and emission-based models (EBM). In this study, by applying OBM and EBM in parallel within a month having significant O₃ pollution in Shanghai, China, we demonstrated that a lack of carbonyl input, overestimation in NO₂ monitoring data, and differences in simulation period and emission reduction area were the core factors leading to OPS discrepancies, and that a reliable OPS cannot be obtained unless these factors are reconciled. By collectively addressing these factors, the number of days with a consistent OPS from both models increased from 6-7 to 20-21 in a month, and the R value defined to quantify the discrepancy decreased by ∼55%. The contributions of these factors to OPS discrepancy differed greatly in urban and suburban settings, mainly caused by differences in pollutant emission and transport characteristics. Overall, OPS identified solely by OBM or EBM is associated with great uncertainty, while reliable OPS estimation can be achieved by a collective application of OBM and EBM with consensus on the above factors. The method demonstrated here could be applied to other photo-chemically active regions worldwide as part of efforts to address ozone pollution.

Measurement and minutely-resolved source apportionment of ambient VOCs in a corridor city during 2019 China International Import Expo episode

In this study, real-time measurement of Volatile Organic Compounds (VOCs) was conducted at an urban site in Changzhou, a typical corridor city in the Yangtze River Delta (YRD) region in China, by Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) during 2019 China International Import Expo (CIIE) episode. An improved method based on Air Quality Index (AQI) value is applied to identify polluted and clean periods. Diurnal pattern of VOC levels revealed elevated photochemical reactivity during polluted periods. Five VOC sources were identified by Positive Matrix Factorization (PMF) model, including secondary formation (22.71 ± 12.33%), biogenic (21.50% ± 11.76%), solvent usage (20.50 ± 10.07%), vehicle exhaust (18.32 ± 8.32%), and industrial process and fuel usage (16.96 ± 13.21%). The mean contribution of vehicular exhaust was 10.84% higher during the nighttime than the daytime under polluted days. The biogenic source contributed more during clean periods, while the secondary formation presented the opposite. Spatial analysis displayed that the VOC concentration was higher in the S and SSE. In terms of the regional transport, short-distance air masses from the northeast and the south within the YRD region led to high VOC levels and biogenic VOC derived from the ocean might affect the entire region. Stringent emission control policies enforced over the YRD for 2019 CIIE provided an excellent opportunity to determine the source-receptor response. As joint control area, the VOC level of Changzhou exhibited a substantial reduction and the VOC amounts emitted by solvent usage showed the biggest decrease (-58%). The findings of this study highlight the superiority of high time-resolved data in identifying the dynamic variation pattern (with the change of time and wind) of VOC levels and emission intensities.

Estimation of Aromatic Secondary Organic Aerosol Using a Molecular Tracer-A Chemical Transport Model Assessment

A modified community multiscale air quality model, which can simulate the regional distributions of 2,3-dihydroxy-4-oxopentanoic acid (DHOPA), a marker species for monoaromatic secondary organic aerosol (SOA), was applied to assess the applicability of using the DHOPA to aromatic SOA mass ratio (f_SOA) from smog chamber experiments to estimate aromatic SOA during a three-week wintertime air quality campaign in urban Shanghai. The modeled daily DHOPA concentrations based on the chamber-derived mass yields agree well with the organic marker field measurements (R = 0.79; MFB = 0.152; and MFE = 0.440). Two-thirds of the DHOPA are from the oxidation of ARO1 (lumped less-reactive aromatic species; mostly toluene), with the rest from ARO2 (lumped more-reactive aromatic species; mostly xylenes). Modeled DHOPA is mainly in the particle phase under ambient organic aerosol (OA) loading but could exhibit significant gas-particle partitioning when a higher estimation of the DHOPA vapor pressure is used. The modeled f_SOA shows a strong dependence on the OA loading when only semivolatile aromatic SOA components are included in the f_SOA calculations. However, this OA dependence becomes weaker when non-volatile oligomers and dicarbonyl SOA products are considered. A constant f_SOA value of ∼0.002 is determined when all aromatic SOA components are included, which is a factor of 2 smaller than the commonly applied chamber-based f_SOA value of 0.004 for toluene. This model-derived f_SOA value does not show much spatial variation and is not sensitive to alternative estimates of DHOPA vapor pressures and SOA yields, and thus provides an appropriate scaling factor to assess aromatic SOA from DHOPA measurements. This result helps refine the quantification of SOA attributable to monoaromatic hydrocarbons in urban environments and thereby facilitates the evaluation of control measures targeting these specific precursors.

Simultaneous observation of atmospheric peroxyacetyl nitrate and ozone in the megacity of Shanghai, China: Regional transport and thermal decomposition

Atmospheric peroxyacetyl nitrate (PAN) and ozone (O₃) are two typical indicators for photochemical pollution that have adverse effects on the ecosystem and human health. Observation networks for these pollutants have been expanding in developed regions of China, such as North China Plain (NCP) and Pearl River Delta (PRD), but are sparse in Yangtze River Delta (YRD), meaning their concentration and influencing factors remain poorly understood. Here, we performed a one-year measurement of atmospheric PAN, O₃, particulate matter with aerodynamic diameter smaller than 2.5 μm (PM_2.5), nitrogen oxides (NO_x), carbon monoxide (CO), and meteorological parameters from December 2016 to November 2017 in Shanghai. Overall, high hourly maximum PAN and O₃ were found to be 7.0 and 185 ppbv in summer, 6.2 and 146 ppbv in autumn, 5.8 and 137 ppbv in spring, and 6.0 and 76.7 ppbv in winter, respectively. Continental air masses probably carried atmospheric pollutants to the sampling site, while frequent maritime winds brought in less polluted air masses. Furthermore, positive correlations (R: 0.72-0.85) between PAN and O₃ were found in summer, indicating a predominant role of photochemistry in their formation. Unlike in summer, weak or no correlations between PAN and O₃ were featured during the other seasons, especially in winter, due to their different loss pathways. Unexpectedly, positive correlations between PAN and PM_2.5 were found in all seasons. During summer, moderate correlation could be attributed to the strong photochemistry acting as a common driver in the formation of secondary aerosols and PAN. During winter, high PM_2.5 might promote PAN production through HONO production, hence resulting in a good positive correlation. Additionally, the loss of PAN by thermal decomposition (TPAN) only accounted for a small fraction (ca. 1%) of the total (PAN + TPAN) during a typical winter episode, while it significantly reached 14.4 ppbv (71.1% of the total) in summer.

Tracer-based characterization of source variations of PM2.5 and organic carbon in Shanghai influenced by the COVID-19 lockdown

Air quality in megacities is significantly impacted by emissions from vehicles and other urban-scale human activities. Amid the outbreak of Coronavirus (COVID-19) in January 2020, strict policies were in place to restrict people's movement, bringing about steep reductions in pollution activities and notably lower ambient concentrations of primary pollutants. In this study, we report hourly measurements of fine particulate matter (i.e., PM_2.5) and its comprehensive chemical speciation, including elemental and molecular source tracers, at an urban site in Shanghai spanning a period before the lockdown restriction (BR) (1 to 23 Jan. 2020) and during the restriction (DR) (24 Jan. to 9 Feb. 2020). The overall PM_2.5 was reduced by 27% from 56.2 ± 40.9 (BR) to 41.1 ± 25.3 μg m^-3 (DR) and the organic carbon (OC) in PM_2.5 was similar, averaged at 5.45 ± 2.37 (BR) and 5.42 ± 1.75 μgC m^-3 (DR). Reduction in nitrate was prominent, from 18.1 (BR) to 9.2 μg m^-3 (DR), accounting for most of the PM_2.5 decrease. Source analysis of PM_2.5 using positive matrix factorization modeling of comprehensive chemical composition, resolved nine primary source factors and five secondary source factors. The quantitative source analysis confirms reduced contributions from primary sources affected by COVID-19, with vehicular emissions showing the largest drop, from 4.6 (BR) to 0.61 μg m^-3 (DR) and the percentage change (-87%) in par with vehicle traffic volume and fuel sale statistics (-60% to -90%). In the same time period, secondary sources are revealed to vary in response to precursor reductions from the lockdown, with two sources showing consistent enhancement while the other three showing reductions, highlighting the complexity in secondary organic aerosol formation and the nonlinear response to broad primary precursor pollutants. The combined contribution from the two secondary sources to PM_2.5 increased from 7.3 ± 6.6 (BR) to 14.8 ± 9.3 μg m^-3 (DR), partially offsetting the reductions from primary sources and nitrate while their increased contribution to OC, from 1.6 ± 1.4 (BR) to 3.2 ± 2.0 μgC m^-3 (DR), almost offset the decrease coming from the primary sources. Results from this work underscore challenges in predicting the benefits to PM_2.5 improvement from emission reductions of common urban primary sources.

Assessing the Effect of Reactive Oxygen Species and Volatile Organic Compound Profiles Coming from Certain Types of Chinese Cooking on the Toxicity of Human Bronchial Epithelial Cells

The International Agency of Research on Cancer identifies high-temperature frying, which features prominently in Chinese cooking, as producing group 2A carcinogens. This study simultaneously characterized particulate and gaseous-phase cooking emissions, monitored their reactive oxygen species (ROS) concentrations, and evaluated their impact on genetic damage and expression in exposed human bronchial epithelial cells. Five types of edible oil, three kinds of seasonings, and two dishes were assessed. Among tested edible oils, heating of soybean oil released the largest particle number concentration (2.09 × 10¹³ particles/(g cooking material and oil)·h) and volatile organic compounds (VOCs) emissions (12103.42 μg/(g cooking material and oil)·h). Heating of lard produced the greatest particle mass concentration (0.75 mg/(g cooking material and oil)·h). The main finding was that sunflower and rapeseed oils produced the highest ROS concentrations (80.48 and 71.75 nmol/(g cooking material and oil)·h, respectively). ROS formation most likely occurred during the autoxidation of both polyunsaturated and monounsaturated fatty acids. Among all the tested parameters, only ROS concentrations exhibited consistency with cell viability and showed significant correlations with the expression levels of CYP1A1, HIF-1a, and especially with IL-8 (the marker for oxidative stress within the cell). These findings indicate that ROS concentration is potentially a suitable metric for direct assessment of exposure levels and potential toxicity.

Emissions of volatile organic compounds (VOCs) from cooking and their speciation: A case study for Shanghai with implications for China

Cooking emission is one of sources for ambient volatile organic compounds (VOCs), which is deleterious to air quality, climate and human health. These emissions are especially of great interest in large cities of East and Southeast Asia. We conducted a case study in which VOC emissions from kitchen extraction stacks have been sampled in total 57 times in the Megacity Shanghai. To obtain representative data, we sampled VOC emissions from kitchens, including restaurants of seven common cuisine types, canteens, and family kitchens. VOC species profiles and their chemical reactivities have been determined. The results showed that 51.26%±23.87% of alkane and 24.33±11.69% of oxygenated VOCs (O-VOCs) dominate the VOC cooking emissions. Yet, the VOCs with the largest ozone formation potential (OFP) and secondary organic aerosol potential (SOAP) were from the alkene and aromatic categories, accounting for 6.8-97.0% and 73.8-98.0%, respectively. Barbequing has the most potential of harming people's heath due to its significant higher emissions of acetaldehyde, hexanal, and acrolein. Methodologies for calculating VOC emission factors (EF) for restaurants that take into account VOCs emitted per person (EF_person), per kitchen stove (EF_{kitchen stove}) and per hour (EF_hour) are developed and discussed. Methodologies for deriving VOC emission inventories (S) from restaurants are further defined and discussed based on two categories: cuisine types (S_type) and restaurant scales (S_scale). The range of S_type and S_scale are 4124.33-7818.04t/year and 1355.11-2402.21t/year, respectively. We also found that S_type and S_scale for 100,000 people are 17.07-32.36t/year and 5.61-9.95t/year, respectively. Based on Environmental Kuznets Curve, the annual total amount of VOCs emissions from catering industry in different provinces in China was estimated, which was 5680.53t/year, 6122.43t/year, and 66,244.59t/year for Shangdong and Guangdong provinces and whole China, respectively. Large and medium-scaled restaurants should be paid more attention with respect to regulation of VOCs.

A meta-analysis evaluating the relationship between IL-18 gene promoter polymorphisms and an individual's susceptibility to HCV infection

BACKGROUND

Several observational studies have investigated interleukin-18 (IL-18) gene polymorphisms with regard to susceptibility to hepatitis C virus (HCV) infection, but the results have been inconsistent.

AIM

To evaluate the relationships between functional polymorphisms in the IL-18 gene and an individual's susceptibility to HCV infection, a meta-analysis was performed. Methods: A literature search was conducted using the PubMed, EMBASE, Web of Science and China BioMedicine databases to investigate the correlation between IL-18 gene polymorphisms and susceptibility to HCV infection. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.

RESULTS

The polymorphisms IL-18-607 C>A and -137 G>C were correlated with susceptibility to HCV infection in Asian populations. However, there was no evidence indicating a correlation between either of these polymorphisms and susceptibility to HCV infection in Caucasian populations.

CONCLUSIONS

Our current meta-analysis suggests that the -607 C>A and -137 G>C polymorphisms in the IL-18 gene promoter play important roles in determining the response to HCV in Asian populations. More studies with larger sample sizes are needed to evaluate the associations between IL-18 genetic polymorphisms and HCV infection risk.

VOC characteristics and inhalation health risks in newly renovated residences in Shanghai, China

BACKGROUND

Exposure to indoor VOCs is expected to link to a variety of negative health outcome. The popularity of decorations and refurbishment in homes in China has given rise to indoor elevated VOC levels, potentially posing health threats to residents.

METHODS

In this study, concentrations of 101 VOC compounds and associated health risks were investigated in newly renovated homes in Shanghai. The potential excess inhalation health risks from home exposure of 17 health-related VOCs were estimated by the Inhalation Unit Risk (IUR) and Reference Concentration (RfC) proposed by US EPA. Monte Carlo simulation and sensitivity analysis were used to assess the uncertainty associated with the estimates of health risks.

RESULTS

The dominant groups by mass concentration were oxygenated VOCs (o-VOCs), aromatics, alkanes and halogenated VOCs (x-VOCs) .12 VOCs with IARC's confirmed or probable carcinogens ratings were detected with a >60% detection frequency in the total samples. The mean concentrations of BTEX (benzene, toluene, m/p-xylene, o-xylene, ethylbenzene) were 2.32μg/m³, 200.13μg/m³, 39.56μg/m³, 32.59μg/m³ and 26.33μg/m³ respectively, generally higher than those in older homes reported in previous studies except benzene. The mean concentration of methylene chloride (47.43μg/m³) and 1,2-dichloroethane (33.83μg/m³) were noticeably higher than the levels reported in previous studies in Hong Kong, Japan and Canada. Whereas the mean concentration of 1,4-dichlorobenzene (5.53μg/m³) were similar to the results of Canadian national survey but lower than those in Japan. The concentrations of 1,2-dichloroethane, 1,4-dichlorobenzene, and methylene chloride, ethylbenzene presented a mean cancer risk at 7.39×10^-6, 1.95×10^-6, 1.62×10^-6, 1.04×10^-6 respectively, above the US EPA proposed acceptable risk level of 1×10^-6. Sensitivity analyses indicated that the VOC exposure concentration have a greater impact than the IUR values on the risk assessment.

CONCLUSION

This study highlights the characteristics of VOCs in recently renovated homes and has implications for the adverse health effects that result from exposure to chlorinated hydrocarbons in indoor air.

Development and use of EST-SSR markers for assessing genetic diversity in the brown planthopper (Nilaparvata lugens Stål)

To assess genetic diversity in populations of the brown planthopper (Nilaparvata lugens Stål) (Homoptera: Delphacidae), we have developed and applied microsatellite, or simple sequence repeat (SSR), markers from expressed sequence tags (ESTs). We found that the brown planthopper clusters of ESTs were rich in SSRs with unique frequencies and distributions of SSR motifs. Three hundred and fifty-one EST-SSR markers were developed and yielded clear bands from samples of four brown planthopper populations. High cross-species transferability of these markers was detected in the closely related planthopper N. muiri. The newly developed EST-SSR markers provided sufficient resolution to distinguish within and among biotypes. Analyses based on SSR data revealed host resistance-based genetic differentiation among different brown planthopper populations; the genetic diversity of populations feeding on susceptible rice varieties was lower than that of populations feeding on resistant rice varieties. This is the first large-scale development of brown planthopper SSR markers, which will be useful for future molecular genetics and genomics studies of this serious agricultural pest.

RNAi-mediated inhibition of the desmosomal cadherin (desmoglein 3) impairs epithelial cell proliferation

OBJECTIVES

  Desmoglein 3 (Dsg3) is a desmosomal adhesion protein expressed in basal and immediate suprabasal layers of skin. Importance of Dsg3 in cell-cell adhesion and maintenance of tissue integrity is illustrated by findings of keratinocyte dissociation in the autoimmune disease, pemphigus vulgaris, where autoantibodies target Dsg3 on keratinocyte surfaces and cause Dsg3 depletion from desmosomes. However, recognition of possible participation of involvement of Dsg3 in cell proliferation remains controversial. Currently, available evidence suggests that Dsg3 may have both anti- and pro-proliferative roles in keratinocytes. The aim of this study was to use RNA interference (RNAi) strategy to investigate effects of silencing Dsg3 in cell-cell adhesion and cell proliferation in two cell lines, HaCaT and MDCK.

MATERIALS AND METHODS

  Cells were transfected with siRNA, and knockdown of Dsg3 was assessed by western blotting, fluorescence-activated cell sorting and confocal microscopy. Cell-cell adhesion was analysed using the hanging drop/fragmentation assay, and cell proliferation by colony forming efficiency, BrdU incorporation, cell counts and organotypic culture.

RESULTS

  Silencing Dsg3 caused defects in cell-cell adhesion and concomitant reduction in cell proliferation in both HaCaT and MDCK cells.

CONCLUSION

  These findings suggest that Dsg3 depletion by RNAi reduces cell proliferation, which is likely to be secondary to a defect in cell-cell adhesion, an essential function required for cell differentiation and morphogenesis.

Isolation of Guinea pig inner hair cells using manual microsurgical dissection

Cochlear inner hair cells (IHCs) and outer hair cells (OHCs) show distinctive morphological features that are usually sufficient to distinguish these two species in vitro. However, OHCs may sometimes resemble IHCs when they are mechanically distorted or begin swelling at their basal end. As a result, accurately discriminating the cells based on morphology was thought to be problematic. An objective method that allows us to clearly and unambiguously distinguish these two cell types is therefore of continued interest. We describe a protocol in which solitary IHCs were harvested from guinea pig cochlea using a manual microsurgical dissection.

[Clinic significance of nm23, collage IV and PCNA expression in non-small cell lung cancer]

BACKGROUND

To study the significance of nm23, collagen IV and PCNA expressions in non-small cell lung cancer.

METHODS

Expressions of the nm23, collagen IV and PCNA in 84 cases of non-small cell lung cancer were examined with SP immunohistochemical technique. Of the 84 cases, there were squamous cell carcinoma 42, adenocarcinoma 42, stage I 27, stage II 24, stage III 24, and stage IV 9. Statistical analysis was performed with Chi-Square test.

RESULTS

Expressions of the nm23, collagen IV and PCNA in 84 cases of non-small cell lung cancer were 60. 7% ( 51/ 84) , 75. 0% ( 63/ 84) and 53. 6% ( 45/ 84) respectively. There was negative correlation between the lymph node metastasis and the expressions of nm23 and collagen IV in squamous cell carcinoma, and the expressions of collagen IV and PCNA were associated with tumor differentiation. No correlation was found between TNM stage and expressions of nm23, collagen IV and PCNA.

CONCLUSIONS

The results indicate that nm23, collagen IV and PCNA participate the modulation of metastasis of non-small cell lung cancer and that they may be used to evaluate the potential of metastasis.

Clinical features of diffuse axonal injury

OBJECTIVE

To analyze the mechanism of diffuse axonal injury (DAI) and study the relationship between DAI and brain concussion, brain contusion, and primary brain stem injury.

METHODS

The clinical data and iconographic characteristics of 56 patients with DAI were analyzed retrospectively.

RESULTS

Traffic accidents were the main cause of DAI. Among t he 56 cases, 34 were injured for at least twice, and 71.43% of the patients were complicated with contusion.

CONCLUSIONS

It is considered that DAI is a common pattern of primary brain injury, which is often underestimated. And DAI includes cerebral concussion and primary brain injury, and is often complicated by cerebral cortex contusion. Therefore, it is very simple and practical to divide primary brain injuries into local and diffuse injuries.

Pharmaceutical significance of the cyclic imide form of recombinant human glial cell line derived neurotrophic factor

PURPOSE

The purpose of this paper is to determine the significance of cyclic imide formation of an aspartic acid residue during storage on the pharmaceutical quality of a recombinant human glial cell line-derived neurotrophic factor (rhGDNF) formulation.

METHODS

A combination of chromatography, peptide mapping, mass spectroscopy, and protein sequencing was used to purify and characterize the degradation product. Circular dichroism, 1,8-ANS and heparin binding, melting temperature determination, bioassays, and preclinical pharmacokinetic and toxicology testing were performed to examine its equivalence to native rhGDNF.

RESULTS

The rhGDNF with cyclic imide at aspartic acid residue 96 showed identical activity, structure, pharmacokinetic profile, and toxicity profile to the native rhGDNF.

CONCLUSIONS

Formation of cyclic imide at aspartic acid residue 96 does not affect the pharmaceutical quality of the rhGDNF formulation.

Functional abrogation of p53 is required for T-Ag induced proliferation in cardiomyocytes

Targeted expression of the SV40 large T-antigen oncoprotein (T-Ag) induces cardiomyocyte proliferation in the atria and ventricles of transgenic mice. Previous studies have identified the p53 tumor suppressor, p107 (a homologue of the retinoblastoma tumor suppressor), and p193 (a novel BH3 only proapoptosis protein) as prominent TAg binding proteins in cardiomyocyte cell lines derived from these transgenic mice. To further explore the significance of these protein-protein interactions in the regulation of cardiomyocyte proliferation, a transgene comprising the human atrial natriuretic factor (ANF) promoter and sequences encoding a mutant T-Ag lacking the p53 binding domain was generated. Repeated micro-injection of this DNA gave rise to genetically mosaic animals with minimal transgene content, suggesting that widespread cardiac expression of mutant T-Ag was deleterious. This notion was supported by the observation that the transgene was selectively lost from the cardiac myocytes (but not the cardiac fibroblasts) in the mosaic animals. Crosses between the mosaic mice and animals expressing a cardiac restricted dominant negative p53 resulted in transgene transmission with ensuing overt cardiac tumorigenesis. Transfection of the mutant T-Ag in embryonic stem (ES) cell-derived cardiomyocytes resulted in wide-spread cell death with characteristics typical of apoptosis. Co-transfection with a dominant negative p53 transgene rescued mutant TAg-induced cell death in the ES-derived cardiomyocyte cultures, resulting in a marked proliferative response similar to that seen in vivo with the rescued transgenic mouse study. These results indicate that T-Ag expression in the absence of p53 functional abrogation results in cardiomyocyte death.

The effect of vitamin A on contraction of the ductus arteriosus in fetal rat

Endogenous retinoic acid may play a role in inducing smooth muscle differentiation in the fetal ductus arteriosus. Maternal administration of retinoic acid may accelerate the process. This study was designed to investigate the effect of vitamin A on developmental changes in the contractile system of the ductus. Vitamin A was injected into pregnant rats and the ductus was isolated from the fetus at 19, 20, or 21 d of gestation. The fetus at 19 d of gestation served as a model of the preterm fetus. The force of contraction and [Ca]i were measured. Membrane depolarization caused by high KCl induced ductal contraction in all age groups studied. In the 19-d fetus, O2 did not cause significant contraction or changes in [Ca]i in the control group, but it did induce a significant contraction and increases in [Ca]i in the vitamin A-treated group. In the 20- and 21-d fetuses, 5% O2-induced contraction in the vitamin A-treated group was significantly greater than in the control group. In the 19-d fetus, noradrenaline-induced contraction and increases in [Ca]i, indicators of the size of the intracellular Ca pool, were observed and they were similar in the control group and in the vitamin A-treated group. These data suggest that 1) in the preterm fetus, the contractile system, including membrane depolarization, [Ca]i increase, and its activation of contractile proteins, is already functioning, but the O2-sensing mechanism is underdeveloped, 2) vitamin A accelerates the development of the O2-sensing mechanism of the ductus arteriosus.

[Clinical use of acellular allogenic dermis or acellular porcine dermis with split-thickness autologous skin graft in 119 cases]

OBJECTIVE

To observe the effect of acellular allogenic dermis or acellular porcine dermis together with split-thickness autologous skin graft on coverage of deep burn wound and the wound of scar excision.

METHODS

Acellular allogenic dermis or acellular porcine dermis produced by our unit, with split-thickness autologous skin graft, were used in repairing various wounds in 119 cases. The take rate of various wounds was compared, and the take rate of wounds in which autologous skin from different sites was used to cover either acellular allogenic dermis or acellular porcine dermis was also compared. Histological examination and follow-up were made in some cases.

RESULTS

After tangential excision, eschar excision and scar excision, the wounds were covered with either allogenic acellular dermis or porcine acellular dermis and autologous split-thickness skin. The take rate was found to be (93.4 +/- 3.4)%, (92.1 +/- 4.6)%, (94.5 +/- 3.5)%, respectively. There was no a significant difference in take rate (P > 0.05). No significant difference in take rate between the transplantation of allogenic acellular dermis with autologous split-thickness skin and transplantation of porcine acellular dermis with autologous split-thickness skin was found (P > 0.05). When autologous split-thickness skin harvested from the trunk or extremities was used, the take rate was (93.1 +/- 4.8)%, (89.0 +/- 6.2)%, respectively, whereas the take rate was only about 70% - 80% when skin harvested from the scalp was used. The take rate was only about 40% when acellular allogenic dermis and autologous micro-skin graft were used to cover the wound. Histological examination 19 months after the transplantation revealed normal structure. Collagenous fibers were orderly arranged. There was no apparent hyperplasia of collagenous fibers. Hair follicles, sweat glands and other skin appendages were not found in the healed area. Grossly, no obvious pigmentation was seen, the surface was smooth with slight wound contraction, and the consistency was flexible.

CONCLUSION

Acellular allogenic split-thickness dermis or acellular porcine split-thickness dermis with autologous split-thickness dermis for coverage of deep burn wound and the wound of scar excision is an ideal material.

Enhanced cardiomyocyte DNA synthesis during myocardial hypertrophy in mice expressing a modified TSC2 transgene

Tuberous sclerosis complex (TSC) is a rare genetic disorder characterized by the appearance of benign tumors in multiple organs, including the heart. Disease progression is accompanied by homozygous mutation at 1 of 2 loci (designated TSC1 or TSC2), leading to the suggestion that these genes function as tumor suppressors. In this study, we generated a series of TSC2 cDNAs in which one or more structural motifs were deleted, with the hope that expression of the modified gene product would override the growth-inhibitory activity of the endogenous TSC2 gene product. Several of the modified cDNAs enhanced growth rate, increased endocytosis, and promoted aberrant protein trafficking when expressed in NIH-3T3 cells, thereby mimicking phenotypes typical of TSC2-deficient cells. Surprisingly, targeted expression of the most potent TSC2 cDNA to the heart did not perturb cardiac development. However, the level of cardiomyocyte DNA synthesis in adult transgenic mice was elevated >35-fold during isoproterenol-induced hypertrophy compared with their nontransgenic siblings. These results suggest that alteration of TSC2 gene activity in combination with beta-adrenergic stimulation can reactivate the cell cycle in a limited number of terminally differentiated adult cardiomyocytes.

Atrial but not ventricular fibrosis in mice expressing a mutant transforming growth factor-beta(1) transgene in the heart

Increased transforming growth factor (TGF)-beta(1) activity has been observed during pathologic cardiac remodeling in a variety of animal models. In an effort to establish a causal role of TGF-beta(1) in this process, transgenic mice with elevated levels of active myocardial TGF-beta(1) were generated. The cardiac-restricted alpha-myosin heavy chain promoter was used to target expression of a mutant TGF-beta(1) cDNA harboring a cysteine-to-serine substitution at amino acid residue 33. This alteration blocks covalent tethering of the TGF-beta(1) latent complex to the extracellular matrix, thereby rendering a large proportion (>60%) of the transgene-encoded TGF-beta(1) constitutively active. Although similar levels of active TGF-beta(1) were present in the transgenic atria and ventricles, overt fibrosis was observed only in the atria. Surprisingly, increased active TGF-beta(1) levels inhibited ventricular fibroblast DNA synthesis in uninjured hearts and delayed wound healing after myocardial injury. These data suggest that increased TGF-beta(1) activity by itself is insufficient to promote ventricular fibrosis in the adult mouse ventricle.

Heritable lympho-epithelial thymoma resulting from a transgene insertional mutation

Thymoma is the most common tumor of the anterior-superior mediastinum. We have identified a line of transgenic mice which spontaneously and heritably develop thymomas at a very high penetrance. The available data suggest that thymoma formation in these mice results as a consequence of transgene insertional mutagenesis. Immune histologic analyses indicate that the thymomas are of epithelial cell origin. Survival studies indicate that tumor progression is more aggressive in females as compared to males (73.9 vs 41.7% mortality at 20 weeks of age, respectively). Fluorescent in situ hybridizations have localized the transgene integration site to the F2-G region of mouse chromosome 2. Translocation encompassing the syntenic region in humans has been implicated in lympho-epithelial thymoma. These animals may constitute a useful resource for the identification of gene(s) which participate in thymoma progression, as well as a model system for screening anti-thymoma therapeutic agents.

Selective inhibition of spinal cord neurite outgrowth and cell survival by the Eph family ligand ephrin-A5

The Eph family tyrosine kinase receptors and their ligands, the ephrins, have been shown to play critical roles in cell migration, tissue morphogenesis, and axonal guidance in many different systems. However, their function in the spinal cord has not been examined carefully. We showed in this study that several Eph receptors, including EphA3, Eph A4, and Eph A5, are expressed in the ventral spinal cord in partially overlapping patterns, with EphA5 exhibiting the most widespread transcription in the entire ventral spinal cord during early development. Complementary to the receptor expression, a ligand of these receptors, ephrin-A5, is transcribed in the dorsal half of the spinal cord. Consistent with the spatial location of receptor expression, the ligand selectively inhibits neurite outgrowth and induces cell death of the ventral, but not the dorsal, spinal cord neurons. These observations suggest that interactions between the Eph family receptors and ligands exerts negative influences on ventral spinal cord neurons and thus may play important roles in regulating morphogenesis and axon guidance in the spinal cord.

[The coat color mutation in silver foxes (Vulpes vulpes): morphology of guard hairs]

The structure of guard hairs was analyzed in the mottling mutants of silver foxes. The mottling mutation occurred in the population of silver foxes which has been subjected to domestication. Hairs from the mottling areas were shown to have the following distinctions from silvery-black hairs: the lack of clear grana-shaft separation, a lesser thickness and length, another shape and pattern of guard-hair scales, another thickness ratio between cortical and medullar layers, a lesser number of melanocytes in hair bulbs, and a lesser number of dendritic processes in melanocytes. Putative mechanisms underlying the phenotypic effect of the mutant gene that controls mottling are suggested.