[Current situation, problems and suggestions of environmental health standardization].

In this paper, the history and current situation of environmental health standardization in China are reviewed, and the experience and shortcomings in the process of environmental health standardization in China are analyzed, suggestions for the next step of environmental health standards are also put forward.

Analysis of imprinted messenger RNA expression in deceased transgenic cloned goats.

Genomic imprinting is an important epigenetic mechanism that has vital effects on fetal growth and development. We observed the differences in four tissues (heart, spleen, liver, and kidney) from dead transgenic cloned goats using hematoxylin and eosin (H&E) staining. Eight imprinted genes in the tissues of dead transgenic cloned and normal goats were analyzed using reverse transcription polymerase chain reaction. H&E staining results from the abortion group indicated the lack of obvious morphological changes in heart and spleen tissues, while inflammatory cell infiltration and glomerular nephritis characteristics were observed in liver and kidney tissues, respectively. Compared to the control group, CDKN1C, H19, IGF2R, and SNRPN were significantly (P < 0.05) overexpressed in the heart tissue of the abortion group, while XIST was significantly reduced. In the liver tissues, CDKN1C and DLK1 expression decreased, while GNAS, H19, IGF2R, PEG3, and XIST expression increased significantly. In the spleen tissues, DLK1 expression increased, while GNAS, H19, IGF2R, PEG3, SNRPN, and XIST expression decreased. In the kidney tissues, CDKN1C, DLK1, GNAS, IGF2R, and PEG3 expression increased, while H19 and XIST expression decreased. The overall expression of imprinted genes was abnormal in different tissues of transgenic cloned goats, and the degree of abnormal genomic imprinting was more severe in the abortion group compared to the death and control groups. These results suggest that abnormal expression of imprinted genes may cause developmental defects in transgenic cloned goats. Moreover, abnormal epigenetic modifications may affect the reprogramming of transgenic donor cells.

Effects of different dietary intake on mRNA levels of MSTN, IGF-I, and IGF-II in the skeletal muscle of Dorper and Hu sheep hybrid F1 rams.

MSTN, IGF-І(insulin-like growth factor-І) and IGF-II (insulin-like growth factor-II) regulate skeletal muscle growth. This study investigated the effects of different dietary intake levels on skeletal muscles. Sheep was randomly assigned to 3 feeding groups: 1) the maintenance diet (M), 2) 1.4 x the maintenance diet (1.4M), and 3) 2.15 x the maintenance diet (2.15M). Before slaughtering the animals, blood samples were collected to measure plasma urea, growth hormone, and insulin concentrations. After slaughtering, the longissimus dorsi, semitendinosus, semimembranosus, gastrocnemius, soleus, and chest muscle were removed to record various parameters, including the mRNA expression levels of MSTN and IGFs, in addition to skeletal muscle fiber diameter and cross-sectional area. The result showed that as dietary intake improved, the mRNA expression levels of MSTN and IGF-II decreased, whereas IGF-Іexpression increased. The mRNA expression levels of MSTN and IGFs were significantly different in the same skeletal muscle under different dietary intake. The skeletal muscle fiber diameter and cross-sectional area increased with greater dietary intake, as observed for the mRNA expression of IGF-І; however, it contrasted to that observed for the mRNA expression of MSTN and IGF-II. In conclusion, dietary intake levels have a certain influence on MSTN and IGFs mRNA expression levels, in addition to skeletal muscle fiber diameter and cross-sectional area. This study contributes valuable information for enhancing the molecular-based breeding of sheep.

Oct4 and Sox2 overexpression improves the proliferation and differentiation of bone mesenchymal stem cells in Xiaomeishan porcine.

Mesenchymal stem cells derived from bone marrow (BMSCs) are a population of self-renewing multipotent cells that are capable of differentiating into various cellular lineages, and are widely employed in tissue engineering and cell therapy. Recently, clinical research involving BMSCs has become increasingly popular. In order to conduct appropriate research, it is first necessary to amplify large amounts of functional BMSCs in vitro. However, after several passages of expanding in vitro, the proliferation and differentiation potential of BMSCs gradually decline. To determine whether overexpression of Oct4 or Sox2 might prevent this decline, we transfected Oct4 or Sox2, which are essential for the pluripotency and self-renewal of embryonic stem cells, into BMSCs of Xiaomeishan porcine by a lentivirus. The results showed that overexpression of Sox2 or Oct4 BMSCs in culture media containing a basic fibroblast growth factor resulted in higher proliferation and differentiation compared to controls, suggesting that genetic modification of stemness-related genes is an efficient way to maintain the proliferation and differentiation potential of BMSCs.

Effect of the IGF-1/PTEN/Akt/FoxO signaling pathway in the duodenal mucosa of rats subjected to water immersion and restraint stress.

The insulin growth factor 1/phosphatase and tensin homologue deleted on chromosome 10/Akt/forkhead box (IGF-1/PTEN/Akt/FoxO) signaling pathway reportedly exhibits gastroprotective effects by reducing water immersion and restraint stress (WRS)-induced gastric mucosal cell apoptosis. We examined the expression and localization of IGF-1, PTEN, Akt, and FoxO proteins, caspase-3 activity, and the number of apoptotic cells in the duodenal mucosa of rats subjected to WRS to confirm whether the IGF-1/PTEN/Akt/FoxO signaling pathway has a role in the duodenal mucosa. The results indicated that WRS enhanced cell apoptosis in the duodenal mucosa. In addition, in normal rats, PTEN was found mainly in the cellular cytoplasm of the duodenal glands and lamina propria of villi. IGF-1 and total Akt were observed in the cellular cytoplasm of the duodenal glands. In addition, total Akt was found in the cellular cytoplasm of the myenteric plexus. FoxO3a and FoxO4 were primarily concentrated in the cellular cytoplasm of the lamina propria. Specifically, PTEN, FoxO3a and FoxO4 were also localized in the cellular cytoplasm of lamina propria of restituted villi in the duodenal mucosa of rat subjected to WRS. In addition, messenger RNA transcript levels of IGF-1, PTEN, Akt1, Akt2, FoxO3, and FoxO4 were upregulated in the duodenal mucosa, with a peak between the 4th and 8th day after 7 h of WRS. Furthermore, the results also suggested that Akt3 messenger RNA transcript levels in the duodenal mucosa of rats after WRS showed no significant differences compared with those in the non-WRS group. Collectively, our results implied that the IGF-1/ PTEN/Akt/FoxO signaling pathway was effective in regulating cellular apoptosis in the duodenal mucosa of rats after WRS.

The dehydration effect on mechanical properties of tooth enamel.

Exploring the subtle mechanical property changes of tooth enamel in different conditions is important for dental research. However, some experimental results can be deceptive and may lead to misunderstanding. In particular, we show the dehydration associated with increased mechanical properties of tooth enamel as monitored by Nanomechanical System Testing (NST) can be misleading. The results indicate that the friction coefficient decreased with an increase of hardness of enamel upon dehydration, which appears to imply that dehydrated enamel has better mechanical properties than hydrated enamel. However, more critical scrutiny of the actual situation, suggests dehydrated teeth enamel are more prone to damage and greater wear. To appreciate the basis for the contrast between the experimental results and reality of natural hydrated enamel, which has better resistance to wear, and is critical for an understanding of the aetiology of enamel resistance to fracture.

[Analysis of related factors of coins foreign bodies crossing the esophagus in 204 cases of children].

Objective:To analyze the related factors of coins crossing the esophagus by themselves in children. Method:Two hundred and four cases with coin esophageal foreign bodies in our hospital from April 2016 to June 2017 were selected,the sex, age, size and texture of foreign body and the time of foreign body insertion were analyzed.Result:Of the 204 children, 46 had esophageal foreign bodies falling off the digestive tract below the esophagus,44 cases were discharged by themselves，2 children were removed under digestive endoscopy，1 coins formed diverticulum at the entrance of esophagus.Conclusion:Coins pass over the esophagus, basically seen within 24 hours，unrelated to age，sex or coin size，but related to the quality of the coin.

Clinical, pathological and unusual MRI features of five synovial sarcomas in head and neck.

OBJECTIVE: Synovial sarcoma (SS) of the head and neck is an unusual malignancy. This article documents five SSs in this region. METHODS: All the patients underwent MR examinations. Four lesions received surgical ablation; one was treated with radiotherapy before surgery. The clinical, pathological and MRI features were reviewed. RESULTS: Four of all five cases were monophasic fibrous-type SS, and the other one was biphasic type that was the fourth documented SS located in the nasopharynx. The symptoms were varied. All the masses were well defined, mainly homogeneous and solid; three of them arose adjacent to the minor joint. The mass parenchyma showed isointense signal on T1 weighted imaging similar to that of the skeletal muscle and hyperintense signal on T2 weighted imaging with remarkable enhancement. Two cases were found with fibrous septum, one with haemorrhage and one with cystic degeneration. Epithelial membrane antigens (EMAs) were all positive. The positive rate of cytokeratin (CK), part pan-CK antibody (AE1/3) and vimentin (Vim) were 50%, 75%, 75%, respectively. CONCLUSION: Well-defined head and neck masses frequently arise adjacent to the minor joint, which are mainly homogeneous and solid, with isointense signal on T1 weighted MRI and hyperintense signal on T2 weighted MRI, and remarkable enhancement should evoke the diagnosis of SS. The positive staining of Vim\AE1/3\EMA and CK facilitates the final diagnosis. ADVANCES IN KNOWLEDGE: The article documents the fourth SS involving the nasopharynx; other locations were also uncommon; three of them arose adjacent to the minor joint. The clinical, pathology and uncommon MR features of SS in the head and neck are also documented.

Mechanical characterization of stomach tissue under uniaxial tensile action.

In this article, the tensile properties of gastric wall were investigated by using biomechanical test and theoretical analysis. The samples of porcine stomach strips from smaller and greater curvature of the stomach were cut in longitudinal and circumferential direction, respectively. The loading-unloading, stress relaxation, strain creep, tensile fracture tests were performed at mucosa-submucosa, serosa-muscle and intact layer, respectively. Results showed that the biomechanical properties of the porcine stomach depended on the layers, orientations and locations of the gastric wall and presented typical viscoelastic, nonlinear and anisotropic mechanical properties. During loading-unloading test, the stress of serosa-muscle layer in the longitudinal direction was 15-20% more than that in the circumferential direction at 12% stretch ratio, while it could reach about 40% for the intact layer and 50% for the mucosa-submucosa layer. The results of stress relaxation and strain creep showed that the variation degree was obviously faster in the circumferential direction than that in the longitudinal direction, and the ultimate residual values were also different for the different layers, orientations and locations. In the process of fracture test, the serosa-muscle layer fractured firstly followed by the mucosa-submucosa layer when the intact layer was tested, the longitudinal strips firstly began to fracture and the required stress value was about twice as much as that in the circumferential strips. The anisotropy and heterogeneity of mechanical characterization of the porcine stomach were related to its complicated geometry, structure and functions. The results would help us to understand the biomechanics of soft organ tissue.

Effect of adsorption time on the adhesion strength between salivary pellicle and human tooth enamel.

Salivary pellicle is a biofilm that is formed by the selective adsorption of salivary proteins. Almost all the functions of the salivary pellicle (lubricating properties, anti-caries properties, etc.) are closely associated with its adhesion strength to tooth surface. The objective of this study was to investigate the effect of adsorption time on the adhesion strength between salivary pellicle and human tooth enamel, aiming to understand what act as the determinant of the interfacial adhesion. In this study, human tooth enamel samples were immersed in human whole saliva in vitro to obtain a salivary pellicle on the surface of enamel. Immersion treatments lasting up to 1, 3, 10 and 60 min were conducted, respectively. Nano-scratch tests were conducted on the surface of enamel after different adsorption times. The wettability of enamel surface was measured through water contact angle. Results showed that the shear energy between salivary pellicle and enamel surface increased exponentially with the adsorption time. The adhesion force between salivary pellicle and bare enamel surface was more than twice that between salivary pellicle and salivary pellicle. It was found that both the wettability and zeta potential of enamel increased obviously after 1 min saliva-adsorption treatment, and then they almost kept stable as the adsorption time further increased. In summary, the adhesion strength between initial salivary pellicle and enamel surface was much higher than that between initial salivary pellicle and outer salivary pellicle. It seemed that electrostatic interaction contributed to the adhesion between the initial salivary pellicle and enamel surface, but not to the adhesion between the initial and outer salivary pellicle. The results would be helpful to extend the understanding of the adhesion mechanism of salivary pellicle and then to develop new artificial saliva and dental restorative materials.

Chemotherapy plus Erlotinib versus Chemotherapy Alone for Treating Advanced Non-Small Cell Lung Cancer: A Meta-Analysis.

BACKGROUND: Whether a combination of chemotherapy and erlotinib is beneficial for advanced non-small cell lung cancer (NSCLC) remains controversial. This study aimed to summarize the currently available evidence and compare the efficacy and safety of chemotherapy plus erlotinib versus chemotherapy alone for treating advanced NSCLC. METHODS: EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials were searched for relevant studies. Our protocol was registered in PROSPERO (CRD42014015015). RESULTS: Nine randomized controlled trials with a total of 3599 patients were included. Compared to chemotherapy alone, chemotherapy plus erlotinib was superior in PFS (HR = 0.76 [95% CI 0.62, 0.92], P = 0.006), and no statistically significant difference was observed in OS (HR = 0.94 [95% CI 0.86, 1.03], P = 0.16). Intercalated erlotinib plus chemotherapy demonstrated improvements in PFS (HR = 0.67 [95% CI 0.50, 0.91], P = 0.009) and OS (HR = 0.82 [95% CI 0.69, 0.98], P = 0.03). Continuous erlotinib plus chemotherapy treatment failed to demonstrate improvements in PFS (HR = 0.91 [95% CI 0.80, 1.04], P = 0.16) and OS (HR = 0.98 [95% CI 0.89, 1.09], P = 0.75). The association of chemotherapy plus erlotinib with improvement in PFS was significant in never smoking patients (HR = 0.46 [95% CI 0.37, 0.56], P<0.00001) but not in smoking patients (HR = 0.70 [95% CI 0.49, 1.00], P = 0.05). Among patients with EGFR mutant tumors, chemotherapy plus erlotinib demonstrated significant improvements in PFS (HR = 0.31 [95% CI 0.17, 0.58], P = 0.0002) and OS (HR = 0.52 [95% CI 0.30, 0.88], P = 0.01). Among patients with EGFR wild-type tumors, no statistically significant difference was observed with respect to PFS (HR = 0.87 [95% CI 0.70, 1.08], P = 0.21) and OS (HR = 0.78 [95% CI 0.59, 1.01], P = 0.06). CONCLUSION: Combination of chemotherapy and erlotinib is a viable treatment option for patients with NSCLC, especially for patients who never smoked and patients with EGFR mutation-positive disease. In addition, intercalated administration is an effective combinatorial strategy.

Location of disulfide bonds in antithrombin III.

Proteolytic digests of human antithrombin III (ATIII) have been analyzed by a combination of reversed-phase high-performance liquid chromatography and fast atom bombardment (FAB) mass spectrometry for disulfide-containing peptides which are diagnostic for disulfide linkages in ATIII. These results indicate that disulfide bonds join Cys 8 and Cys 128, Cys 21 and Cys 95, and Cys 247 and Cys 430. In addition, these results demonstrate that systematic searches of the amino acid sequence of a large protein for segments with molecular weights matching FAB mass spectral information is a viable method for identifying peptides independent of the specificity of the enzyme used to fragment the protein.

Assignment of disulfide bonds in proteins by partial acid hydrolysis and mass spectrometry.

A new method is described for locating disulfide bonds in proteins which cannot be cleaved between half-cystinyl residues by enzymic methods, as is often the case for tightly coiled proteins, or for proteins in which half-cystinyl residues are not separated by residues required for enzymic cleavage. Partial acid hydrolysis of a model protein, hen egg-white lysozyme, produces a mixture of disulfide-containing peptides from which the disulfide connections may be deduced. The usefulness of a combination of HPLC, fast atom bombardment mass spectrometry, and computer-assisted analysis to identify disulfide-containing peptides present in the partial acid hydrolysate of the model protein is demonstrated. Chromatographic fractions of the hydrolysate were analyzed by mass spectrometry before and after chemical reduction of the disulfide bonds to determine the molecular weights of disulfide-containing peptides. Computer-assisted analysis was then used to relate the molecular weights of these peptides to specific segments of the protein from which the disulfide connectivities could be determined. Partial acid hydrolysis of proteins, which is attractive because it proceeds relatively independent of the amino acid sequence and structure, and because disulfide interchange is unlikely to occur in dilute acid, has become practical because disulfide-containing peptides present in complex mixtures can be identified rapidly and definitively by this method.

3,9-Bis(dicyanomethylene)-2,4,8,10-tetrathiaspiro[5.5]undecane.

The title compound, 2,2'-(2,4,8,10-tetrathiaspiro[5.5]undecane-3,9-diylidene)bis(propanedinitrile), C(13)H(8)N(4)S(4), has been designed and synthesized for use as a potential new organic molecular electronic material. The spiro-annulated structure has twofold symmetry and is formed by two equal push-pull ethylene units, with the cycloalkylthio groups as electron donors and the cyano groups as electron acceptors. The intermolecular S.N non-bonded separation within a layer in the lattice is 3.296 (6) A, indicating a strong intermolecular interaction between the cyano groups and the S atoms, while the S atoms in two neighbouring molecules have a shortest S.S contact of 3.449 (3) A. In addition, attractive C-H.N and C-H.S interactions bridge adjacent molecules either within a layer or between layers. In short, these four types of intermolecular interactions combine to form an extended three-dimensional network in the lattice, resulting in a highly ordered array of molecular packing.