Model predictions of toxaphene degradation in the atmosphere over North America

Technical toxaphene, a broad-spectrum pesticide mixture, degrades in the environment, resulting in potential changes in toxicity. The present study uses a multimedia model that the authors developed to estimate toxaphene degradation in the atmosphere over North America. The predicted degradation has strong spatial and temporal variability determined by processes such as emission and transport of technical toxaphene, as well as the complex interactions among many species (e.g., toxaphene, hydroxyl [OH] radicals, and ozone). More toxaphene is degraded in warmer months due to higher concentrations of technical toxaphene (primarily due to higher technical toxaphene emissions in the southeastern United States and transport to other regions) and OH radicals. In the model, OH radicals are created primarily through the reactions of water vapor with the excited oxygen atom, O(¹D), generated by the photolysis of ozone, which is produced primarily by reactions of volatile organic compounds and nitrogen oxides (NOx) in the presence of sunlight. The higher OH concentrations in warmer months are primarily the result of higher solar radiation and ozone concentrations. The spatial distribution of degradation depends on the distribution of technical toxaphene soil residues as well as atmospheric transport and chemistry; significant chemical degradation occurs in the southeastern United States where soils are most heavily contaminated by past applications of toxaphene.

In vitro study on cytotoxicity and intracellular formaldehyde concentration changes after exposure to formaldehyde and its derivatives

HeLa cells were exposed to formaldehyde and its metabolic derivatives, methanol, formic acid, and acetaldehyde, to investigate that the toxicity of formaldehyde is not caused by the chemical group. After 1 h of treatment with formaldehyde, mitochondrial assays showed that low concentrations (e.g. 10 μmol/L) of formaldehyde promoted growth of the HeLa cells, while higher concentrations (e.g. ≥62.5 μmol/L) inhibited cell growth; while all four chemicals at a concentration of 125 μmol/L affected cell growth, formaldehyde affected the largest. Reactive oxygen species concentration increased with the concentration of the exposure chemical. The endogenous formaldehyde content increased the most in the formaldehyde group, but in other three groups, it did not increase as the exposure concentration increased. Expression of dehydrogenase (formaldehyde dehydrogenase (FDH)) in the formaldehyde (10.40) and methanol (10.60) groups increased significantly compared with the control (1), while it was similar to the control in formic acid (0.90) and acetaldehyde (1.10) groups. Our results suggest that formaldehyde could affect cell activity and even enter cells. Exposure to formaldehyde changes the endogenous formaldehyde concentration in cells within 24 h, and this induces expression of FDH for formaldehyde degradation to maintain the formaldehyde balance. The toxicity of formaldehyde is not caused by the carbon atoms in the aldehyde, hydroxyl, or carboxyl groups. Formaldehyde is hypothesized to be an important signaling molecule in the regulation of cell growth and maintenance of the endogenous formaldehyde level.

Implementation of high-resolution SNP arrays in the investigation of fetuses with ultrasound malformations: 5 years of clinical experience

Chromosome microarray analysis (CMA) has proven to be a powerful tool in postnatal patients with intellectual disabilities, and it is increasingly used in prenatal diagnosis. However, its diagnostic capabilities in prenatal diagnosis vary, and clinical experiences have failed to establish a consensus regarding CMA indications, the design and resolution of microarrays, and the notification and interpretation of copy number variations (CNVs). We present our 5 years of clinical experience using whole-genome high-resolution single nucleotide polymorphism (SNP) arrays to investigate 446 fetuses that had structural malformations detected with ultrasound but for which standard karyotyping analysis showed normal karyotypes. CMA revealed genomic CNVs in 323 (72.4%) cases and clinically significant CNVs in 11.4% of the fetuses (51/446), including 2 cases of uniparental disomy (UPD) as well as 1 case of cryptic mosaic monosomy of chromosome X. Variants of unknown significance (VOUS) existed in 2.0% of the tested fetuses (9/446). Our results demonstrate the value of whole-genome high-resolution SNP arrays in fetuses with congenital malformations and give a higher detection rate of clinically significant genomic imbalance, especially for detecting UPD. Sufficient communication between technicians and genetic counselors, along with parental testing and comparison with data from in-house or international sources, can significantly reduce VOUS.

Laboratory studies on secondary organic aerosol formation from crude oil vapors

Airborne measurements of aerosol composition and gas phase compounds over the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico in June 2010 indicated the presence of high concentrations of secondary organic aerosol (SOA) formed from organic compounds of intermediate volatility. In this work, we investigated SOA formation from South Louisiana crude oil vapors reacting with OH in a Potential Aerosol Mass flow reactor. We use the dependence of evaporation time on the saturation concentration (C*) of the SOA precursors to separate the contribution of species of different C* to total SOA formation. This study shows consistent results with those at the DWH oil spill: (1) organic compounds of intermediate volatility with C* = 10(5)-10(6) μg m(-3) contribute the large majority of SOA mass formed, and have much larger SOA yields (0.37 for C* = 10(5) and 0.21 for C* = 10(6) μg m(-3)) than more volatile compounds with C*≥10(7) μg m(-3), (2) the mass spectral signature of SOA formed from oxidation of the less volatile compounds in the reactor shows good agreement with that of SOA formed at DWH oil spill. These results also support the use of flow reactors simulating atmospheric SOA formation and aging.

Sequencing-based gene network analysis provides a core set of gene resource for understanding thermal adaptation in Zhikong scallop Chlamys farreri

Marine organisms are commonly exposed to variable environmental conditions, and many of them are under threat from increased sea temperatures caused by global climate change. Generating transcriptomic resources under different stress conditions are crucial for understanding molecular mechanisms underlying thermal adaptation. In this study, we conducted transcriptome-wide gene expression profiling of the scallop Chlamys farreri challenged by acute and chronic heat stress. Of the 13 953 unique tags, more than 850 were significantly differentially expressed at each time point after acute heat stress, which was more than the number of tags differentially expressed (320-350) under chronic heat stress. To obtain a systemic view of gene expression alterations during thermal stress, a weighted gene coexpression network was constructed. Six modules were identified as acute heat stress-responsive modules. Among them, four modules involved in apoptosis regulation, mRNA binding, mitochondrial envelope formation and oxidation reduction were downregulated. The remaining two modules were upregulated. One was enriched with chaperone and the other with microsatellite sequences, whose coexpression may originate from a transcription factor binding site. These results indicated that C. farreri triggered several cellular processes to acclimate to elevated temperature. No modules responded to chronic heat stress, suggesting that the scallops might have acclimated to elevated temperature within 3 days. This study represents the first sequencing-based gene network analysis in a nonmodel aquatic species and provides valuable gene resources for the study of thermal adaptation, which should assist in the development of heat-tolerant scallop lines for aquaculture.

The influence of food on the pharmacokinetics of amlodipine and losartan after single-dose of its compound tablets in healthy chinese subjects

We aim to identify the effects of food on the pharmacokinetics (PK) of amlodipine, losartan and losartan's active metabolite (EXP3174) after oral administration of the Compound Amlodipine Tablets with single dose in healthy Chinese subjects. 12 subjects took the compounds (10 mg/100 mg, amlodipine/losartan) at the conditions of a high-fat breakfast and an overnight fast with a washout period of 14 days. Plasma samples were obtained at scheduled time, and determined by HPLC-MS/MS for the concentrations of amlodipine and HPLC-MS for the concentrations of losartan and EXP3174, respectively. PK parameters were calculated using Software Drug and Statistics (Version 2.0). When tablets were co-administered with food, there was no significant difference of AUC for amlodipine and losartan, but the AUC of EXP3174 was reduced by 19.1%. Meanwhile, the Cmax of amlodipine, losartan and EXP3174 were reduced by 11.4%, 20.0% and 41.4%, and the Tmax of losartan and EXP3174 were 1.3 and 1.8 h longer, respectively. No significant difference was found at t1/2 following food intake. In conclusion, the Compound Amlodipine Tablets, are affected by food administration by reducing the AUC of EXP3174. It is thus suggested that the Compound Amlodipine Tablets should be administered 1 h before or 2 h after meal.

Microbial basis of oral malodor development in humans

To better understand the microbial basis of oral malodor development in humans, we used a cross-sectional and longitudinal study design and the pyrosequencing approach to track and compare the tongue microbiota associated with oral malodor in 29 Chinese adults who underwent a consecutive three-day evaluation for the amount of H2S excreted orally. Three levels of the oral malodor state (healthy, oral malodor, and severe oral malodor) were defined based on the H2S level. Community structure of the tongue plaques was more sensitive to changes of malodor state than to interpersonal variations or differences in sampling times. Within each individual, the structure of microbiota was relatively stable, while their variations were correlated with the change in the H2S level. Severe oral malodor microbiota were the most conserved in community structure, whereas the healthy ones were relatively varied. Oral-malodor-associated bacteria were identified. The relative abundance of Leptotrichia and Prevotella was positively correlated with oral malodor severity, whereas Hemophilus and Gemella exhibited a negative relationship with oral malodor severity. Our study provides one of the first landscapes of oral microbiota changes associated with oral malodor development and reveals microbes potentially useful to the evaluation and control of oral malodor.

Transcriptome profiling of the whitefly Bemisia tabaci reveals stage-specific gene expression signatures for thiamethoxam resistance

Bemisia tabaci has developed high levels of resistance to many insecticides including the neonicotinoids and there is strong evidence that for some compounds resistance is stage-specific. To investigate the molecular basis of B. tabaci resistance to the neonicotinoid thiamethoxam we used a custom whitefly microarray to compare gene expression in the egg, nymph and adult stages of a thiamethoxam-resistant strain (TH-R) with a susceptible strain (TH-S). Gene ontology and bioinformatic analyses revealed that in all life stages many of the differentially expressed transcripts encoded enzymes involved in metabolic processes and/or metabolism of xenobiotics. Several of these are candidate resistance genes and include the cytochrome P450 CYP6CM1, which has been shown to confer resistance to several neonicotinoids previously, a P450 belonging to the Cytochrome P450s 4 family and a glutathione S-transferase (GST) belonging to the sigma class. Finally several ATP-binding cassette transporters of the ABCG subfamily were highly over-expressed in the adult stage of the TH-R strain and may play a role in resistance by active efflux. Here, we evaluated both common and stage-specific gene expression signatures and identified several candidate resistance genes that may underlie B. tabaci resistance to thiamethoxam.

Performance of imaging modalities in the diagnosis of hepatocellular carcinoma: a systematic review and meta-analysis

PURPOSE

The recent guidelines published in 2011 suggest the use of only one imaging method for the final imaging diagnosis of hepatocellular carcinoma. To evaluate the methods in the context of the available literature evidence, this systematic review aimed at assessing the relative performance of different imaging techniques currently used in clinical practice.

MATERIALS AND METHODS

MEDLINE and EMBASE were searched from January 1996 to June 2011, with no language limitation. Eligible trials had to be conducted in patients with suspicion or diagnosis of hepatocellular carcinoma; compare at least two of the following imaging modalities: magnetic resonance imaging, computed tomography, ultrasound; have pathological findings as a reference standard. An analysis also including non-comparative studies was performed as a validation of the main comparison results.

RESULTS

Of 5,144 screened papers, 16 studies fulfilled the eligibility criteria for the comparative analysis and 65 were eligible for the non-comparative analysis. The overall sensitivity and specificity derived by the pooled analysis were 0.78 and 0.77 for computed tomography, 0.84 and 0.84 for magnetic resonance imaging and 0.86 and 0.77 for ultrasound, respectively. In the pair-wise comparisons, ultrasound showed a statistically better specificity than magnetic resonance imaging (0.86 vs. 0.78; p = 0.014) and a statistically better sensitivity than computed tomography (0.88 vs. 0.78; p = 0.030).

CONCLUSION

The present systematic review did not show an obvious superiority of one imaging method. Since their accuracy is not completely overlapping, the possibility of reaching better performance by combining methods should be considered in future prospective trials.

H19 DMR methylation correlates to the progression of esophageal squamous cell carcinoma through IGF2 imprinting pathway

BACKGROUND

H19 gene has been proved to be essential for human tumor growth which contains CpG rich regions. Imprinted gene expression in many cancers is usually associated with the function of methylation. We performed this study to better understand wether H19 DMR methylation correlates to the progression of esophageal squamous cell carcinoma through IGF2 imprinting pathway.

METHODS

LOI of IGF2 was detected in 276 samples, which were determined as heterozygote with ApaI polymorphism in exon 9 of IGF2 by PCR-RFLP and RT-PCR-RFLP. Methylation status of H19 DMR in informative samples was analyzed by bisulfite sequencing PCR. IGF2 expression was examined by real-time PCR and IHC.

RESULTS

208 ESCC patients were informative for ApaI polymorphism. 92 tumor and 30 normal tissues showed IGF2 LOI. Methylation status of H19 CBS6 was higher in patients with IGF2 LOI compared to patients with IGF2 MOI (p < 0.05). IGF2 expression in patients with IGF2 LOI was higher than patients with IGF2 MOI (p < 0.05) which was correlated with lymph node involvement, neoplastic grade and metastasis (p < 0.05).

CONCLUSIONS

Our results suggested that H19 CBS6 hypermethylation is related to the LOI of IGF2 which usually leads to an overexpression of IGF2, playing important roles in the occurrence, development as well as metastasis of ESCC. Therefore, H19 CBS6 methylation potentially represents a novel clinically relevant epigenetic marker to identify individuals at increased risk for the occurrence, progression and prognosis of ESCC.

[Lux1540nm fractional laser treatment for superficial scar]

OBJECTIVE

To observe the effect of non-ablative fractional laser Lux1540nm in superficial scars therapy.

METHODS

According to the Fitzpatrik skin type and scar appearances, appropriate laser energy and pulse width were selected for scar treatment. Therapeutic effect and side-effect was evaluated by preoperative photos and 6 months of postoperative photos.

RESULTS

The total effective rate was 78.12% (28/32). 7 cases (21.88%) showed ineffective results. The therapeutic effect was improved along the increase of treatments. Temporary hyperpigmentation was found in 3 cases (9.38%) and faded away within 3-6 months. Temporary erythema faded away within 4-24 hours.

CONCLUSION

The treatment of non-ablative fractional laser Lux1540nm for superficial scar is effective with minimum side effect.

Contrast and correlations between coarse and fine particulate matter in the United States

The characteristics of concentrations of PM₁₀₋₂.₅, PM₂.₅, and PM₁₀ at 77 sites in the United States are evaluated. PM₁₀ concentrations show strong spatial variability, with highest levels occurring in the southwestern United States, driven primarily by PM₁₀₋₂.₅. PM₁₀₋₂.₅ and PM₂.₅ concentrations show different spatial patterns. The highest concentrations of PM₁₀₋₂.₅ were observed at sites in the southwestern US, leading to the highest PM₁₀ concentrations there. The PM₂.₅ concentrations are the major contributors to the average PM₁₀ concentrations at many sites in the eastern United States. Poor correlations were generally found between PM₁₀₋₂.₅ and PM₂.₅, suggesting that PM₁₀₋₂.₅ and PM₂.₅ are generally influenced by different sources. PM₁₀₋₂.₅ is generally more variable than PM₂.₅ because PM₁₀₋₂.₅ has a higher deposition velocity and is primarily emitted from mechanical processes (e.g. agricultural harvest and construction) that are more influenced by factors including human operation and wind speed leading to a strong episodic nature. As a result of its high variability, PM₁₀₋₂.₅ acts as the major driver for PM₁₀ extremes. PM₁₀₋₂.₅ is significantly correlated with PM₁₀ at all investigated sites, with the average correlation value R(2)=0.79. Correlations of PM₂.₅ with PM₁₀ (average of 0.37) are overall considerably lower than those between PM₁₀₋₂.₅ and PM₁₀. Different seasonal, weekly, and diurnal patterns were observed between PM₁₀₋₂.₅ and PM₂.₅ at agricultural, on-road traffic, quarrying, airport, and marine sites. At investigated agricultural sites, while the concentrations of PM₂.₅ are higher in winter when there are few agricultural activities, PM₁₀₋₂.₅ concentrations are lower in winter months than in summer and autumn months, with highest levels corresponding to harvest and planting. The harvest and planting signatures were not observed in PM₂.₅ concentrations at any of these sites, suggesting that agricultural activities do not have a strong influence on PM₂.₅ concentrations.

The effects of music on brain functional networks: a network analysis

The human brain can dynamically adapt to the changing surroundings. To explore this issue, we adopted graph theoretical tools to examine changes in electroencephalography (EEG) functional networks while listening to music. Three different excerpts of Chinese Guqin music were played to 16 non-musician subjects. For the main frequency intervals, synchronizations between all pair-wise combinations of EEG electrodes were evaluated with phase lag index (PLI). Then, weighted connectivity networks were created and their organizations were characterized in terms of an average clustering coefficient and characteristic path length. We found an enhanced synchronization level in the alpha2 band during music listening. Music perception showed a decrease of both normalized clustering coefficient and path length in the alpha2 band. Moreover, differences in network measures were not observed between musical excerpts. These experimental results demonstrate an increase of functional connectivity as well as a more random network structure in the alpha2 band during music perception. The present study offers support for the effects of music on human brain functional networks with a trend toward a more efficient but less economical architecture.

Exposure to bisphenol A disrupts meiotic progression during spermatogenesis in adult rats through estrogen-like activity

The effect of bisphenol A (BPA) on the reproductive system is highly debated but has been associated with meiotic abnormalities. However, evidence is lacking with regard to the mechanisms involved. In order to explore the underlying mechanisms of BPA-induced meiotic abnormalities in adult male rats, we exposed 9-week-old male Wistar rats to BPA by gavage at 0, 2, 20 or 200 μg/kg body weight (bw)/day for 60 consecutive days. 17β-Estradiol (E2) was administered at 10 μg/kg bw/day as the estrogenic positive control. Treatments with 200 μg/kg bw/day of BPA and E2 significantly decreased sperm counts and inhibited spermiation, characterized by an increase in stage VII and decrease in stage VIII in the seminiferous epithelium. This was concomitant with a disruption in the progression of meiosis I and the persistence of meiotic DNA strand breaks in pachytene spermatocytes,and the ataxia-telangiectasia-mutated and checkpoint kinase 2 signal pathway was also activated; Eventually, germ cell apoptosis was triggered as evaluated by terminal dUTP nick-end labeling assay and western blot for caspase 3. Using the estrogen receptor (ER) antagonist ICI 182780, we determined that ER signaling mediated BPA-induced meiotic disruption and reproductive impairment. Our results suggest that ER signaling-mediated meiotic disruption may be a major contributor to the molecular events leading to BPA-related male reproductive disorders. These rodent data support the growing association between BPA exposure and the rapid increase in the incidence of male reproductive disorders.

[Effects of four dental alloys on apoptosis related gene and protein expression of fibroblast L929]

OBJECTIVE

To investigate the effects of the leaching liquids of 4 differents kinds of dental alloys (Au alloy, Ag-Pd alloy, Co-Cr alloy, Ni-Cr alloy) on apoptosis related gene and protein of fibroblast L929.

METHODS

The L929 cells of mouse were treated in vitro with leaching liquids of 4 different kinds of dental alloys, Au alloy (group A), Ag-Pd alloy(group B), Co-Cr alloy(group C) and Ni-Cr alloy(group D). The RPMI1640 cell medium containing 10% fetal calf serum was served as a control(group E). The effects of these alloys on the expression of caspase-3, 8, 9 of L929 cells were examined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry method. Results After 48 h culture, the mRNA levels of caspase-3 and caspase-9 demonstrated significant differences between the groups expect group A and group E. The mRNA levels of caspase-8 had no change in all groups. The expression of caspase-3 and caspase-9 were significant differences between the groups expect group A and C, group B and D. The expression of caspase-8 had no change in all grotps.

CONCLUSION

The leaching liquids of 4 different kinds of dental alloys expect Au alloy may induce cell appotosis through mitochondrion pathway.