Stem cells from human exfoliated deciduous teeth correct the immune imbalance of allergic rhinitis via Treg cells in vivo and in vitro.

BACKGROUND: Several studies have demonstrated that mesenchymal stem cells can ameliorate the inflammation of allergic rhinitis (AR) and correct the Th1/Th2 immune imbalance. METHODS: This study was performed to explore the immunomodulation properties of stem cells from human exfoliated deciduous teeth (SHEDs) in the treatment of AR in vivo and in vitro. BALB/c mice were sensitized to ovalbumin (OVA) by intraperitoneal injection, and then SHEDs or bone marrow mesenchymal stem cells (BMMSCs) were injected intravenously before challenge. We evaluated nasal symptoms, inflammatory infiltration of nasal mucosa, immunoglobulin secretion, cytokine production, and mRNA expression in the spleen. In addition, peripheral blood mononuclear cells (PBMCs) from AR patients were cultured with SHEDs or BMMSCs in the presence of phytohemagglutinin (PHA). PBMCs cultured alone with or without PHA served as controls. After 3 days of culture, we examined the effect of SHEDs on T lymphocyte proliferation, cytokine secretion, and the proportion of Foxp3+ Treg cells via flow cytometry. Finally, to determine the role of soluble factors (TGF-ß1, PGE2) in the immunomodulatory mechanism, a cytokine neutralization assay was performed. RESULTS: Nasal symptoms and inflammatory infiltration were significantly reduced after SHED administration. The OVA-specific IgE and IgG1 levels in serum were significantly decreased, and the increased IL-4, IL-5, IL-13, and IL-17A levels in the spleen after OVA challenge were markedly downregulated, while the level of IFN-γ was upregulated by SHED administration. The mRNA expression levels also changed correspondingly. SHEDs significantly inhibited the proliferation of T lymphocytes; increased the levels of IFN-γ, IL-10, PGE2, and TGF-ß1; decreased the levels of IL-4 and IL-17A; and induced the expansion of Treg cells in the coculture system. The neutralization of TGF-ß1 partly relieved the immunosuppression of SHEDs, but blocking PGE2 did not. In addition, SHEDs were superior to BMMSCs in inhibiting the Th2 immune response in vivo and inducing the expansion of Treg cells in vitro. CONCLUSION: These results suggest that SHEDs could correct the CD4+ T cell immune imbalance via Treg cells and may be potential therapeutic agents for the treatment of allergic diseases, such as AR, in the future.

[Investigations of microscopic morphology of individual inhalable particulates in Macao in summer].

By means of high resolution field emission scanning electron microcopy (FESEM) and image analysis (IA), microscopic morphologies and the number-size and volume-size distributions of different types of individual inhalable particles collected in Macao in summer of 2007 were investigated. The results showed that the soot aggregates and mineral particles were ubiquitous in the PM10 of Macao in July, 2007. The mineral particles mostly showed an irregular morphology and the soot aggregates displayed chain-like and fluffy morphology. The soot aggregates accounted for approximately 30%-40% in average by number, and the mineral particles accounted for approximately 20%. The relatively higher percentages of more soot aggregates implied that emission from motor vehicle exhausts was serious in Macao during summer. The number-size distributions revealed that the majority of the particles in PM10 of Macao were fine particles, with the equivalent diameter being concentrated in a range from 0.2-0.4 microm. A distinct spatial difference existed in the types of particles collected at different sampling sites. Soot particles dominated the busy transportation sites and the tunnel site, while the mineral particles had a higher proportion at the dock site.

Characterization of surface runoff from a subtropics urban catchment.

Characteristics of surface runoff from a 0.14-km2 urban catchment with separated sewer in Macau was investigated. Water quality measurements of surface runoff were carried out on five rainfall events during the period of August to November, 2005. Water quality parameters such as pH, turbidity, TSS, COD, TN, Zn, Pb, and Cu were analyzed. The results show that TN and COD are the major pollutants from surface runoff with mean concentration of 8.5 and 201.4 mg/L, both over 4-fold higher compared to the Class V surface water quality standard developed by China SEPA. Event mean concentration (EMC) for major pollutants showed considerable variations between rainfall events. The largest rainfall event with the longest length of antecedent dry weather period (ADWP) produced the highest EMC of TN, TSS and COD. From the pollutographs analysis, the peak concentration of TN precedes the peak runoff flow rate for all three rainfall events. The tendency of the concentration of TSS, turbidity and COD changing with runoff flow varies between rainfall events. The relationship between TSS and other parameters were analyzed to evaluate the efficiency of the physical treatment process to control the surface runoff in the urban catchment. Based on the correlation of parameters with TSS, high treatment efficiency of TSS, TN and COD was expected. The most significant event in term of first flush is the one with the strongest rainfall intensity and longest length of ADWP. TN always showed first flush phenomenon in all three rainfall events, which suggested that the surface runoff in the early stage of surface runoff should be dealt with for controlling TN losses during rainfall events.

[Characterization of urban surface runoff in two urban catchments in Macau].

Characteristics of pollutants from urban surface runoff were investigated. Two catchments with a seperated system in Macau were selected for sampling on rainfall events during the period of August to November, 2005. Water quality parameters such as pH, turbidity, TSS, COD, TOC, TN, TP, Zn, Pb, and Cu were analyzed. The results show that the commercial-residential urban catchment shows high level of COD, TN, TP, and the park urban catchment has high TN and TP concentration. From the pollutograph analysis, the peak of TSS, TN, TP concentration appears in the first and the third sample respectively in ELH and YLF catchments, and then the pollutants concentration tend to decrease. Regression analysis between TSS and TN & TP in two urban catchments resulted in a high value (R2 > 0.95) of the coefficient of determination R2 indicating a close relationship between soil losses and nitrogen & phosphorus discharged from surface runoff. The profile of TSS and COD discharged from surface runoff relates greatly to the surface flow change, whereas the surface flow change has little influence on the profile of TN and TP. The heavy metals such as Zn, Pb and Cu fluctuate with the continuous input of vehicles during rainfall events. Pollutants such as TSS, TN, COD discharged from surface runoff depend greatly on the dry periods and storms intensity in such two urban catchments.

[Choice experiment method and its application to solid waste management in Macao].

Economic valuation of environmental goods or services has been becoming a research frontier and hotspot of environmental economics in the world. Choice experiment (CE) is a relatively new method that can be used to value the economic benefits of environmental goods or services. This paper reports an attempt to apply the CE method in Macao that aimed to understand Macao residents' preferences for solid waste management programs. A random sample survey of 260 respondents in Macao was conducted during the summer in 2004. Survey data was analyzed using multinomial logit models. Results from 260 in-person interviews indicate that Macao residents preferred waste segregation and recycling at source and noise reduction during waste collection and transportation. The study concludes that CE is a reliable tool in the analysis of respondents' preferences for the development of suitable solid waste management programs in Macao.

[Primarily study of alkylphenols in sediment core from Nam Van artificial lake of Macao].

Alkylphenols, nonylphenols (NPs), octylphenol (OP), are known to have estrogenic effects. In a sediment core from Nam Van artificial lake of Macao, the concentrations of NPs ranged from 2.17 to 5.91 microg/g, with mean value of 3.66 microg/g during the estuarine sedimentary environment from 1970s-1980s and from 0.69 to 3.04 microg/g, with mean value of 2.08 microg/g during lagoon sedimentary environment in 1990s. The concentrations of OP during the initial stages of lagoon environment in the early 1990s were similar to that in the estuarine environment, and ranged from 14.33 to 39.11 ng/g. Subsequently, the concentration of OP was rapidly decreasing from 6.52 to 2.58 ng/g. Sources of APs in the estuarine condition included the urban runoffs from the upstream waters of Pearl River Delta and Macao city, but just from Macao in the lagoon condition. Consequently, concentration of APs in estuary condition was higher than that in lagoon condition. The vertical profile of concentration of APs in the sediment core, to some degree, was correlated with the development degree of regional economy and the proceeding of wastewater treatment. The results also showed that the alkylphenols in overlapping silty layer preferred to transfer downward to filling sandy layer.

[Study on on-board measurements and modeling of vehicular emissions].

It's a basic work to study the characteristics of vehicular emissions and give emission factors for development of vehicular emission inventory and decision-making of the control strategies. On-board emission measurements of on-road vehicles are regarded as important complementary to emission laboratory dynamometer tests. On-board exhaust emission measurements were conducted on seven samples of gasoline cars in a typical road in Macao, using AVL DiGas 4000 light five-gas analyzer. It was found that there was an obvious reduction of gaseous pollutant emissions from cars equipped with electronic fuel injection and three-way catalytic converter system (referred to as EFI cars in the following), compared to old carburetor cars. The average volume concentrations of CO, HC and NO of carburetor cars were 227 x 10(-6), 1.57% and 1477 x 10(-6), respectively, while those of EFI cars were 33 x 10(-6), 0.21% and 131 x 10(-6), which were about 1/11 through 1/7 of the former. However, there were high emissions during the cold start of EFI cars. The arithmetical mean concentrations of CO and NO emissions of EFI cars were calculated and their absolute values were predominantly contributed by high concentrations with low frequency. Furthermore, the emission factors of gasoline cars were estimated by test data, and at the same time, MOBILES model was used to calculate average emission factors of gasoline cars in Macao in 2000. The ratios between the results calculated by model and estimated by experiment data were in the range of 59%-139%, which would narrow into 68%-132% if only annual average emission factors were compared. The results suggest that EFI + TWC systems equipped in vehicles have good effect on the emission reduction, but catalytic converters are not activated during the cold start. Technical improvement of EFI cars, which could reduce the occurrence of high emissions with low frequency during the operation, would decrease their average level on exhaust emissions a lot. Furthermore, it's reliable that the emission factors of gasoline cars in Macao calculated by modified MOBILES model.