Netrin-4: Focus on Its Role in Axon Guidance, Tissue Stability, Angiogenesis and Tumors.

Netrin-4, a member of the Netrins family, is an important secreted protein that plays a role in axonal outgrowth and migration orientation. It was initially described that Netrin-4 had a high correlation with the laminin ß-chain and promoted the growth of neurites in cultured olfactory bulb explants. Subsequently, it was discovered that Netrin-4 is involved in regulating various physiological processes, including angiogenesis, the occurrence and metastasis of various tumors, and the development of the kidney and alveoli. This paper reviews the current research on Netrin-4 since its discovery and provides a theoretical basis for further research on the biological characteristics of Netrin-4. Effects of Netrin-4. Netrin-4 regulates axon guidance, angiogenesis and the development of various tumors.

Response of microbial community to different land-use types, nutrients and heavy metals in urban river sediment.

Nutrients and heavy metals (HM) in the sediment have an impact on microbial diversity and community structure. In this study, the distribution characteristics of nutrients, HM, and microbial community in the sediments along the Longsha River, a tributary of the Pearl River (or Zhu Jiang), China were investigated by analyzing samples from 11 sites. On the basis of the HM-contamination level, the 11 sampling sites were divided into three groups to explore the changes in microbial communities at different ecological risk levels. Results indicated that nutrient concentrations were higher near farmlands and residential lands, while the ecological risk of HM at the 11 sampling sites was from high to low as S10 > S2 > S9 > S6 > S11 > S7 > S5 > S8 > S3 > S4 > S1. Among these HM, Cu, Cr, and Ni had intense ecological risks. In addition, the results of Variance Partitioning Analysis (VPA) revealed a higher contribution of HM (35.93%) to microbial community variation than nutrients (12.08%) and pH (4.08%). Furthermore, the HM-tolerant microbial taxa (Clostridium_sensu_stricto_1, Romboutsia, norank_o__Gaiellales, and etc.) were the dominant genera, and they were more dynamic around industrial lands, while microbes involved in the C, N, and S cycles (e.g., Smithella, Thiobacillus, Dechloromonas, Bacter oidetes_vadinHA17, and Syntrophorhabdus) were inhibited by HM, while their abundance was lower near industrial lands and highway but higher around residential lands. A three-unit monitoring program of land-use types, pollutants, and microbial communities was proposed. These results provide a new perspective on the control of riparian land-use types based on contaminants and microbes, and different microbial community response patterns may provide a reference for contaminant control in sediments with intensive industrial activities.

[Quantitative risk assessment of the polycyclic aromatic hydrocarbons dietary exposure from edible fats and oils in China].

OBJECTIVE: To assess the quantitative risk of the polycyclic aromatic hydrocarbons (PAHs) dietary exposure from edible fats and oils in China. METHODS: One hundred samples of edible fats and oils were collected from the supermarkets and the farmers markets in 11 provinces of China from December in 2013 to May in 2014. Then they were tested for EU15+1 PAHs (16 PAHs were controlled in priority by European Food Safety Authority) by two test methods which were QuECHERS-GC-MS-MS and GPC-HPLC-FLD. Data of PAHs concentration and edible fats and oils consumption which were from Chinese National Nutrition and Health Survey in 2002 were combined to evaluate carcinogenic risk of PAHs in edible fats and oils by the method of margin of exposure (MOE). In this process, we divided the population into 6 groups, namely male adults (older than 18 years old), female adults (older than 18), male youths (13-17), female youths (13-17), school-agers (6-12) and preschoolers (2-5), and thought carcinogenicity as the critical toxicity end point of PAHs. Two quantitative risk assessment methods, i.e. point assessment and probability assessment, were used to evaluate the dietary exposure and MOEs. RESULTS: EU15+1 PAHs in one of 100 samples were not detected, other samples were polluted in different degrees; the detection rates were 3%-98% and the average contents were 0.26-3.26 µg/kg. The results of PAHs dietary exposure from both of point assessment and probability assessment were the same. The average exposures of PAH8 were as the following: male adults were 10.03 and (9.34 ± 12.61) ng·kg(-1)·d(-1)(The former was from point assessment and the latter from probability assessment, the same below), female adults were 9.95 and (9.60 ± 15.04) ng · kg(-1)·d (-1), male youths were 11.09 and (10.84 ± 16.54) ng·kg(-1)·d(-1), female youths were 10.06 and (9.58 ± 12.87) ng·kg(-1)·d(-1),school-agers were 15.29 and (15.62 ± 25.54) ng·kg(-1)·d(-1), preschoolers were 19.27 and (19.22 ± 28.91) ng·kg(-1)·d(-1). MOEs of mean and 50% exposure levels in different group of people were more than 10,000, while MOEs of 95% exposure levels in school-agers and preschoolers were less than 10,000. CONCLUSION: For general consumers, the health risk of PAHs exposure is very low. However, for high-end consumers (95% exposure level) from the sensitive groups (school-ager and preschooler) has a potential health risk.

High-intensity interval training stimulates remyelination via the Wnt/ß-catenin pathway in cuprizone-induced demyelination mouse model.

OBJECTIVES: This study aims to investigate the role of high-intensity interval training (HIIT) in promoting myelin sheath recovery during the remyelination phase in cuprizone (CPZ)-induced demyelination mice and elucidate the mechanisms involving the Wnt/ß-catenin pathway. METHODS: After 5 weeks of a 0.2% CPZ diet to induce demyelination, a 4-week recovery phase with a normal diet was followed by HIIT intervention. Mice body weight was monitored. Morris water maze (MWM) gauged spatial cognition and memory, while the open field test (OFT) assessed anxiety levels. Luxol fast blue (LFB) staining measured demyelination, and immunofluorescence examined myelin basic protein (MBP) and platelet-derived growth factor receptor-alpha (PDGFR-α). Western blotting analyzed protein expression, including MBP, PDGFR-α, glycogen synthase kinase-3ß (GSK3ß), ß-catenin, and p-ß-catenin. Real-time PCR detected mRNA expression levels of CGT and CST. RESULTS: HIIT promoted remyelination in demyelinating mice, enhancing spatial cognition, memory, and reducing anxiety. LFB staining indicated decreased demyelination in HIIT-treated mice. Immunofluorescence demonstrated increased MBP fluorescence intensity and PDGFR-α+ cell numbers with HIIT. Western blotting revealed HIIT reduced ß-catenin levels while increasing p-ß-catenin and GSK3ß levels. Real-time PCR demonstrated that HIIT promoted the generation of new myelin sheaths. Additionally, the Wnt/ß-catenin pathway agonist, SKL2001, decreased MBP expression but increased PDGFR-α expression. DISCUSSION: HIIT promotes remyelination by inhibiting the Wnt/ß-catenin pathway and is a promising rehabilitation training for demyelinating diseases. It provides a new theoretical basis for clinical rehabilitation and care programs.

Solifenacin promotes remyelination in cuprizone mouse model by inhibiting the Wnt/ß-catenin signaling pathway.

Demyelinating diseases are a type of neurological disorder characterized by the damage to the myelin sheath in the central nervous system. Promoting the proliferation and differentiation of oligodendrocyte precursor cells (OPCs) is crucial for treatment. Non-selective muscarinic receptor (MR) antagonists have been shown to improve remyelination in rodent models, although the mechanisms are still unclear. In this study, we treated cuprizone (CPZ)-induced demyelination mouse model with different concentrations of Solifenacin (Sol), a selective M3 receptor antagonist, to determine the optimal concentration for promoting remyelination. Behavioral tests and Luxol fast blue (LFB) staining were used to observe the extent of remyelination, while immunofluorescence was used to measure the expression levels of myelin-related proteins, including myelin basic protein (MBP) and platelet-derived growth factor receptor alpha (PDGFR-α). Western blot analysis was employed to analyze the expression levels of molecules associated with the Wnt/ß-catenin signaling pathway. The results showed that Sol treatment significantly promoted myelin regeneration and OPCs differentiation in CPZ-induced demyelination mouse model. Additionally, Sol treatment inhibited the Wnt/ß-catenin signaling pathway and reversed the effects of CPZ on OPCs differentiation. In conclusion, Sol may promote the differentiation of OPCs by inhibiting the Wnt/ß-catenin signaling pathway, making it a potential therapeutic option for central nervous system demyelinating diseases.

Burden of self-reported acute gastrointestinal illness in China: a population-based survey.

BACKGROUND: Acute gastrointestinal illness (AGI) is an important public-health problem worldwide. Previous national studies of the incidence of AGI in China were performed decades ago, and detailed information was not available. This study therefore sought to determine the magnitude, distribution, and burden of self-reported AGI in China. METHODS: Twelve-month, retrospective face-to-face surveys were conducted in 20 sentinel sites from six provinces between July 2010 and July 2011. RESULTS: In total, 39686 interviews were completed. The overall adjusted monthly prevalence of AGI was 4.2% (95% confidence interval, 4.0-4.4), corresponding to 0.56 episodes of AGI per person-year. Rates of AGI were highest in children aged < 5 years. Healthcare was sought by 56.1% of those reporting illness. Of the cases who visited a doctor, 32.7% submitted a stool sample. The use of antibiotics was reported by 49.7% of the cases who sought medical care and 54.0% took antidiarrhoeals. In the multivariable model, gender, age, education, household type, residence, season, province and travel were significant risk factors of being a case of AGI. CONCLUSIONS: This first population-based study in China indicated that AGI represents a substantial burden of health. Further research into the specific pathogens is needed to better estimate the burden of AGI and foodborne disease in China.

[Prevalence survey of using characteristics of quality, quantity, origin and composition claims on food labels in China].

OBJECTIVE: To understand the using characteristics of quality, quantity, origin and composition claims on food labels in China. METHODS: To get the label samples from different size of supermarket by taking photos in Beijing, and also samples were provided by provincial quality technical supervision, et al. Then extracted the claims from the label samples, classified the samples by determined food categories, and analyzed the using characteristics of these claims. RESULTS: The constituent ratio of quality, quantity, origin and composition claims were 29.48%, 2.24%, 29.21%, 31.81% among all the samples. The constituent ratio of snacks (16.11%) was maximum among all the samples using quality claims, and grain and its products (36.00%) for quantity claims, meat and meat products (22. 09%) for origin claims, snacks (27.04%) for composition claims. "Nature, Natural" (48.63%) was the most used claims among all the samples using quality claims, "Exaggerated capacity" (44.00%) was the most for quantity claims, "Product of , From, Manufactured in" (34.36%) was the most for origin claims, and "Pure, 100% , All" (38.03%) was the most for composition claims. CONCLUSION: The using of quality, quantity, origin, and composition claims is frequently on food labels in China, and a lot of studies should be taken on this field, government should also enact regulations to regulate the use of this claims.

[Expert investigation on food safety standard system framework construction in China].

OBJECTIVE: Through investigating food safety standard framework among food safety experts, to summarize the basic elements and principles of food safety standard system, and provide policy advices for food safety standards framework. METHODS: A survey was carried out among 415 experts from government, professional institutions and the food industry/enterprises using the National Food Safety Standard System Construction Consultation Questionnaire designed in the name of the Secretariat of National Food Safety Standard Committee. RESULTS: Experts have different advices in each group about the principles of food product standards, food additive product standards, food related product standards, hygienic practice, test methods. According to the results, the best solution not only may reflect experts awareness of the work of food safety standards situation, but also provide advices for setting and revision of food safety standards for the next. CONCLUSION: Through experts investigation, the framework and guiding principles of food safety standard had been built.

[Foodborne illness report systems in China].

OBJECTIVE: To introduce the current foodborne illness report system in China. METHODS: Foodborne illness (food poisoning included) report system and food related unusual cases reported system were characterized by their report definitions, scopes and report procedures as well as their differences. RESULTS: From October, 2010 to June, 2012, there are 2961 centers of disease control and prevention and heath executive organizations at the different local levels registered in the foodborne illness (food poisoning included) report system and 1525 incidents were reported. There were 553 hospitals registered in the food related unusual cases reported system while only 38 cases reported. CONCLUSION: The foodborne illness report system has been set up in China and further efforts in capacities building are needed.

Ebselen alleviates white matter lesions and improves cognitive deficits by attenuating oxidative stress via Keap1/Nrf2 pathway in chronic cerebral hypoperfusion mice.

Oxidative stress is crucial in cerebral white matter lesions (WMLs) induced by chronic cerebral hypoperfusion. Therefore, ameliorating oxidative damage is considered to be a beneficial strategy for the treatment of WMLs. Ebselen (EbSe), a small lipid organoselenium compound, its lipid peroxidation activity is mediated through the glutathione peroxidase-mimetic properties. This study aimed to investigate the role of EbSe in WMLs after bilateral common carotid artery stenosis (BCAS). The BCAS model can moderately reduce cerebral blood flow, and mimics white matter damage caused by chronic cerebral hypoperfusion or small vessel disease. Laser Speckle Contrast Imaging (LSCI) was used to monitor the cerebral blood flow of mice. The spatial learning and memory were tested by using the eight-arm maze. LFB staining was used to detect demyelination. The expression of MBP, GFAP and Iba1 was assayed by immunofluorescence. The demyelination was assessed by Transmission Electron Microscope (TEM). The activities of MDA, SOD and GSH-Px were detected by assay kits. The mRNA levels of SOD, GSH-Px and HO-1 was detected by realtime PCR. The activation of the Nrf2/ARE pathway and the expression of SOD, GSH-Px and HO-1was assessed by Western blot. EbSe ameliorated cognitive deficits and white matter lesions induced by bilateral common carotid artery stenosis (BCAS). The expression of GFAP and Iba1 was decreased in the corpus callosum of BCAS mice after EbSe treatment. Moreover, EbSe alleviated the level of MDA by elevating the expression and mRNA of SOD, GSH-Px and HO-1 in BCAS mice. Furthermore, EbSe promoted the dissociation of the Keap1/Nrf2 complex, resulting in the accumulation of Nrf2 in the nucleus. This study demonstrates a favorable effect of EbSe on cognitive impairment in a chronic cerebral hypoperfusion model, and the improvement of EbSe's antioxidant property is mediated by Keap1/Nrf2 pathway.

[Effects of recombinant human lactoferrin on improving the iron status of IDA rats].

OBJECTIVE: To investigate the effect of recombinant human lactoferrin (rhLf) separated and purified from milk of transgenic cows on improving the iron status of rats suffered from iron deficiency anemia (IDA). METHOD: The IDA model of female weaning Wistar rats was induced by iron deficient diet, and the rats were then randomly divided into 6 groups (12 rats in each group, based on their body weight and the concentration of hemoglobin) : group A (the model control ), group B, C and D (rhLf 0.375. 0.75 or 2.25 g/kg BW), group E (ferrous lactate 0.011 g/kg BW), and group F (ferrous lactate 0.011 g/kg BW + rhLf 0.375 g/kg BW). Test substances were administered by gavage daily for 8 weeks. Related indexes, including general health condition, body weight, hematological parameters, free erythrocyte protoporphyrin (FEP), serum iron (SI), total iron binding capacity (TIBC), serum ferritin (SF), serum Cu and serum Zn, were determined. RESULTS: After 8 weeks of supplementation, body weight, RBC, Hb, SI, TS and SF levels of rats in group E and F were improved and significantly higher than those in group A, while levels of FEP, TIBC and Zn were lower. Indexes of rats in group D were also significantly different from those in group A but with a less degree than those in group E or F. Compared with group A, there were no obvious difference in iron status for group B or C except for more RBC and lower levels of FEP and Zn in group C, as well as the lower level of Zn in group B. SI, TS and SF levels in group F were significantly higher but TIBC was lower than those in group E. CONCLUSION: The iron status of IDA rats could be improved to some degree by the supplementation of rhLf alone, but the effect was weaker than that of ferrous lactate. The effect of combining rhLf with ferrous lactate was more intensive than ferrous lactate or rhLf administered individually.

Inhibitory effects of visible 650-nm and infrared 808-nm laser irradiation on somatosensory and compound muscle action potentials in rat sciatic nerve: implications for laser-induced analgesia.

Low-level laser therapy (LLLT) has been shown in clinical trials to relieve chronic pain and the World Health Organization has added LLLT to their guidelines for treatment of chronic neck pain. The mechanisms for the pain-relieving effects of LLLT are however poorly understood. We therefore assessed the effects of laser irradiation (LI) on somatosensory-evoked potentials (SSEPs) and compound muscle action potentials (CMAPs) in a series of experiments using visible (λ = 650 nm) or infrared (λ = 808 nm) LI applied transcutaneously to points on the hind limbs of rats overlying the course of the sciatic nerve. This approximates the clinical application of LLLT. The 650-nm LI decreased SSEP amplitudes and increased latency after 20 min. CMAP proximal amplitudes and hip/ankle (H/A) ratios decreased at 10 and 20 min with increases in proximal latencies approaching significance. The 808-nm LI decreased SSEP amplitudes and increased latencies at 10 and 20 min. CMAP proximal amplitudes and H/A ratios decreased at 10 and 20 min. Latencies were not significantly increased. All LI changes for both wavelengths returned to baseline by 48 h. These results strengthen the hypothesis that a neural mechanism underlies the clinical effectiveness of LLLT for painful conditions.

[Endothelium-dependent vasorelaxation effects induced by apigenin on the thoracic aorta of rats and its possible mechanism].

OBJECTIVE: To investigate the vasorelaxant effect and mechanism of apigenin. METHODS: Rats were anesthetized with 1% sodium pentobarbital (i. p.) and killed by exsanguination. The thoracic aorta was isolated and cut into 3-4 mm rings and suspended in an organ bath filled with 20 ml Kreb solution which was maintained at 37 degrees C and ventilated continuously with 95% O2 and 5% CO2. The contraction was measured with a multichannel acquisition and analysis system (BIO-PAC MP150, America). Related studies were conducted on the effect of apigenin on the contraction induced by phenylephrine (PE) and role of endothelium, K+ channel as well as Ca2+ channel in PE-induced relaxation. RESULT: Apigenin had no effect on the basal tension in rat aortic rings. Apigenin can relax PE pre-contracted rings in both endothelium-intact aortic and endothelium-denuded aortic in a dose-dependent manner, with the effect of endothelium-intact aortic significantly stronger than that of endothelium-denuded aortic (P < 0.05). Pre-incubation of endothelium-intact rings with L-NAME and methylene blue significantly reduced apigenin-induced relaxation (P < 0.05). However, indomethacin did not significantly affect the apigenin-induced relaxation in endothelium-intact rings (P > 0.05). 4-AP, 5-HD, TEA as well as BaCl2 significantly inhibited apigenin-induced relaxation in endothelium-denuded rings pre-contracted by PE (P < 0.05). In the K(+)-free solution, apigenin can significantly inhibit PE pre-contracted aortic rings (P < 0.05). In the Ca2(+)-free solution plus PE, cumulative addition of CaCl2 induced a stepwise tension increase of aortic rings. Pretreated with apigenin significantly attenuated CaCl2 induced contraction. CONCLUSION: Apigenin induces both endothelium-dependent and independent relaxation. NO and cGMP are involved in the endothelium-dependent relaxation, inhibition of voltage-dependent or receptor-operate Ca2+ channel or extracellular Ca2+ influx and activation of K channel contribute in part to the endothelium-independent relaxation by apigenin.

[Assessment of dietary iodine intake of population in non-high-iodine areas in China].

OBJECTIVE: To assess the potential risk of dietary iodine insufficiency of population in non-high-iodine areas (water iodine < 150 microg/L) in China. METHOD: The dietary iodine intake of 13 age-sex population groups were estimated by combining the data of iodine intake from food, table salt and drinking water. Two conditions were considered: consuming iodized salt or non-iodized salt. The data of food and table salt consumption were derived from the Chinese National Nutrition and Health Survey in 2002. Water consumption was calculated as the recommended water intake. Iodine contents of food, table salt and water were calculated from China Food Composition Table and iodine surveillance data. RESULTS: Under the condition of consuming iodized salt, the average iodine intake of all population groups was higher than the Recommended Nutrient Intake (RNI), while the iodine intakes of individuals above Upper Limits (UL) and below RNI were 5.8% and 13.4% respectively, and the iodine intake of individuals lower than the Estimated Average Requirement (EAR) was 9.4% in adults above 18 years of age (including pregnant and lactating women). If non-iodized salt was consumed, the average iodine intake of most sex-age population groups was higher than RNI, but the iodine intake of 97.6% of individuals would be lower than RNI, while the iodine intake of 97.4% of adults would be lower than EAR. The contribution of iodine from table salt was much higher than that from drinking water and food in the condition of consuming iodized salt, while food was the predominant contributor of dietary iodine in the condition of consuming non-iodized salt. CONCLUSION: The health risk of iodine deficiency was higher than that of iodine excess in areas where water iodine was < 150 p.g/L in China, and the risk of iodine insufficiency was much higher if non-iodized salt was consumed. Iodized salt should be the main sources of dietary iodine intake for population in areas where water iodine was < 150 microg/L in China.

[Boron background value survey of some foodstuffs in 12 provinces of China and boron primary intake estimation of Chinese habitants].

OBJECTIVE: To learn boron background value of some foodstuffs in China and estimation the primary intake of boron. METHODS: A total of 1035 grain, meat and fruit samples collected from 12 provinces in 2010 were analyzed for boron by ICP-MS. The primary intake of boron was estimated by using the data of "Survey on the Status of Nutrition and Health of Chinese People" in 2002. RESULTS: Soybeans contain the highest concentration of boron among all the surveyed foodstuffs, with the background valued is 39.46 mg/kg. Fruit and pork contain second highest concentration of boron, with the background value range from 4 mg/kg to 7 mg/kg. Beef, mutton, rice and wheat flour contain less boron than other foodstuffs, with background value less than 4 mg/kg. The primary intake of boron for Chinese habitants is 1.62 mg per day and rice is the main source of dietary boron. CONCLUSION: Boron concentration varies in different foodstuffs and soybeans are rich in boron. The average intake of boron for Chinese habitants was among the safe range if no illegal boron added to food.

Assessment on dietary melamine exposure from tainted infant formula.

OBJECTIVE: To estimate the dietary melamine exposure in Chinese infants and young children from the consumption of melamine adulterated Sanlu infant formula. METHODS: Four age groups of infants and young children (3, 6, 12, and 24 months) were chosen as the assessed subjects and the maximum amount of infant formula consumption was estimated based on the recommended usage level in the package insert of Sanlu infant formula and other brands. Melamine was analyzed in 111 Sanlu infant formula samples collected from the markets in Beijing and Gansu province using the LC-MS-MS with a limit of quantification of 0.05 mg/kg. Four levels of melamine concentration were chosen to estimate the dietary intakes, including the mean, median, 90th percentile, and maximum. RESULTS: The infants of 3 months had the highest intake of melamine, and with the increase of the age (month), the intake decreased. Based on the median melamine concentration (1,000 mg/kg) as an example, the melamine intakes for the infants of 3, 6, 12, and 24 months were 23.4, 21.4, 15.0, and 8.6 mg/kg bw/d, respectively. CONCLUSION: Dietary melamine intakes from tainted Sanlu infant formula significantly exceeded the TDI level (0.2 mg/kg bw/d) recommended by the WHO Expert Meeting in 2008. However, the present assessment has some limitations including the poor representative samples, the varied melamine concentrations in the adulterated Sanlu infant formula, and other brand infant formula possibly consumed by these infants.

[Study on the validation of application model on embryonic stem test].

OBJECTIVE: According trend of differentiation cardiomyocyte of embryonic stem cell,the model of EST has been built and the validation of the model is needed to be tested. It is profit to improve the method of safety evaluation. METHODS: The embryonic stem cell differentiates into cardiomyocyte in different concentrations of Penicillin G,DPH and 5-FU with hanging and suspending culture conditions. With the results of cytotoxicity, the different embryonic toxicity characteristics of different substants may be detected clearly. RESULTS: The ID50 (D3) concentration of three embryo toxicants were 1099, 47.4 and 0.023 microg/ml. Penicillin G, DPH and 5-FU were discriminated as none-embryotoxicity, weak-embryotoxicity and strong-embryotoxicity. CONCLUSION: Test compounds between three classes were discriminated correctly .The validation of EST model that established by us is high.

[Safety assessment of starters culture bacteria in fermented milk in China].

In this study, we analysised the safety of 137 strains of starters culture bacteria in fermented milk between 2000 and 2006 in China. The study was designed to evaluate the acute oral toxicity of 137 strains to mice, and 31 of 137 strains for Minimum inhibitory concentrations (MIC) of 20 kinds of antibiotics by broth micro-dilution method. The result indicated that except a strain of Lactobacillus rhamnosus, other probiotics were non-pathogenic and safe for human consumption. 31 strains of probiotics were sensitive to Ampicillin, Penicillin, Imipenem, Gentamicine, Amoxicillin, Amoxicillin/clavulanic acid, Gatifloxacin, Erythromycin, Clindamycin, and were resistant to Nalidixic acid, Vancomycine, Fosfomycin.

[Study on inducing differentiation of mouse embryonic stem cells into cardiomyocyte in vitro].

OBJECTIVE: To study the differentiation from embeyonic stem cells into cardiomyocyte. METHODS: Gene alpha/ beta-MHC, a specific gene of cardiomyocyte and another three house-keeping genes were detected by RT-PCR from the ESCs of 0-,2-,4-,6-,8-, 10-,12-,14-,16-,18- and 20 day and ESCs of 0-,3-, 5- and 10 day with specific culture condition. RESULTS: ESCs started to express alpha/betaMHC gene from 6 day and the levels of alpha/betaMHC increased with culture time. The levels of 14 day's alpha/betaMHC were the highest. After 14 day, alpha/betaMHC gene kept the stable levels. The levels of three house-keeping genes changed significantly with culture time, and GAPDH kept the best stability of three genes. CONCLUSION: The cycle of the differentiation from ESCs into cardiomyocyte in vitro could be designed as 10 - 12 days and GAPDH could be selected as the fittest inner comparison.

Temporal and Spatial Variation in the Abundance of Total and Pathogenic Vibrio parahaemolyticus in Shellfish in China.

We investigated the abundance of total and pathogenic Vibrio parahaemolyticus in shellfish sampled from four provinces in China during May 2013 and March 2014 using the most probable number-polymerase chain reaction (MPN-PCR) method. Total V. parahaemolyticus was detected in 67.7% of 496 samples. A total of 38.1% and 10.1% of samples exceeded 1,000 MPN g(-1) and 10,000 MPN g(-1), respectively. V. parahaemolyticus densities followed a seasonal and geographical trend, with Guangxi and Sichuan shellfish possessing total V. parahaemolyticus levels that were 100-fold higher than those of the Liaoning and Shandong regions. Moreover, the levels of V. parahaemolyticus were at least 10-fold higher in the summer and autumn than in the cooler seasons. Pathogenic V. parahaemolyticus levels were generally lower than total V. parahaemolyticus levels by several log units and tended to be high in samples contaminated with high total V. parahaemolyticus levels. The aqua farms had a lower prevalence but higher abundance of total V. parahaemolyticus compared to retail markets. The catering markets showed the lowest levels of total V. parahaemolyticus, but 20.0% of samples exceeded 1,000 MPN g(-1). The levels of both total and pathogenic V. parahaemolyticus in oysters were higher than in clams. The log-transformed abundance of V. parahaemolyticus was significantly correlated with both water temperature and air temperature but not water salinity. These results provide baseline contamination data of V. parahaemolyticus in shellfish in China, which can be applied to local risk assessments to prioritize risk control to key sectors and evaluate the effectiveness of future control measures.