BACKGROUND:Bone marrow mesenchymal stem cells have potential to self-renewal and multi-lineage differentiation. But after a long period of culture in vitro, the proliferation and differentiation capacities of bone marrow mesenchymal stem cells gradual y loss, the mechanism underlying which is not clear now.
OBJECTIVE:To observe the expression of autophagy-related gene Beclin-1 in differentiation from human bone marrow mesenchymal stem cells into neuron-like cells in vitro.
METHODS:The changes of morphological characteristics of neuron-like cells differentiated from human bone marrow mesenchymal stem cells induced by epidermal growth factor were observed. The expression of neuron-specific enolase and glial fibril ary acidic protein in treated and untreated human bone marrow mesenchymal stem cells were detected using immunocytochemistry. The Beclin-1 protein expressions were detected by western blot before and after induction.
RESULTS AND CONCLUSION:After being induced, human bone marrow mesenchymal stem cells presented classical neuron-like morphology;the expressions of neuron-specific enolase and glial fibril ary acidic protein were 78.7%and 8.1%, respectively. The expression of Beclin-1 protein was changed correspondingly during the induction, which increased after 30 minutes of induction and decreased gradual y after 1 hour of induction. Human bone marrow mesenchymal stem cells could be induced into neuron-like cells in vitro by epidermal growth factor. Autophagy-related gene was highly expressed in the induction of early differentiation and the expression gradual y reduced until it remained at a low level during the differentiation.

Objective To investigate the genotype and drug resistance of extended-spectrum beta-lac-tamases(ESBLs) -producing Shigella in pediatric patients.Methods A total of 59 strains of Shigella were isolated from stool specimens of hospitalized children with shigellosis in Beijing Children's Hospital from January 2004 to December 2008.Phenotypic confirmatory test,which is based on Clinical and Laboratory Standards Institute(CLSI),was used to detect the ESBLs-producing strains.Agar dilution method was used to determine the minimal inhibitory concentration (MIC).PCR amplification was performed for ESBLs producers to determine the genotype.PCR product was sequenced and then analyzed to confirm the subtype of ESBLs.Results Of the 59 isolates,21 (35.6%) strains were identified as ESBLs producers.The 21 strains of ESBLs-producing Shigella all carried the genes of CTX-M as shown by PCR,and CTX-M-1,CTX-M-9 accounted for 6,15,respectively.Among the 21 CTX-M producers,there were 4 strains accompanied by TEM-type and 6 strains accompanied by OXA-type.Nucleotide sequence analysis showed that there were CTX-M-3 (n = 1),CTX-M-15 (n = 2),CTX-M-57(n =3) of the 6 CTX-M-1-producing isolates.The subtypes of CTX-M-9,TEM,OXA were all CTX-M-14,TEM-1,OXA-1,respectively.The sensitive drugs to ESBLs producers were imipenem,meropenem,piperacillin/tazobactam,cefoperazone/sulbactam and cefoxitin,with resistance rate all less than 15%.The resistance to ceftazidime was remarkably variable among different CTX-M producers.Conclusion The prevalence of ESBLsproducing Shigella is in a high level in pediatric patients in this area.The genotypes of ESBLs are all CTX-M.Most of them are CTX-M-14,but some are CTX-M-3,CTX-M-15 and CTX-M-57.Most ESBLs-producing strains are multidrug resistant.Carbopenems should be the first choice for ESBLs producers.

Human cytomegalovirus(HCMV)infection is quite prevalent in population. HCMV triggers important disorders in pregnant women,immune-compromised individuals and organ-transplant patients. For dec-ades,more and more scholars believe that NK cells are important immune cells against HCMV. The activity of NK cells largely depends on the balance between the signals transducted by inhibitory receptors and activatory re-ceptors,therefore the study of NK receptors is of great importance. It may be helpful to the basic research and clinical treatment of HCMV infection. Here,this paper reviews the changes and the molecular mechanism of NK receptors in the control of HCMV infection.

Objective:To investigate the apoptosis by thiocoraline in combination with cisplatin on cervical cell line c4-1 and Hela and its mechanism. Methods:Different concentrations of thiocoraline and cisplatin alone or in combination used for cultured c4-1 and Hela cells. The inhibition of cell proliferation was detected by MTT assay,and the apoptosis was detected by Hoechst 33342 and AO-EB staining. The expressions of the protein Bax,Bcl2,p53,p21 were detected by Western blot. The cell cycle of c4-1 and Hela cells were detected by Flow cytometry. Results: The cell proliferation activity of c4-1 and HeLa cells were inhibited obviously by different concentrations of thiocoraline and cisplatin alone or in combination. The inhibition effect was in a dose-dependent manner. Meanwhile, when the concentrations of thiocoraline and cisplatin were 10 nmol/L and 4 μmol/L, respectivity the inhibitory effect was most significant (P<0. 05);Hoechst 33342 and AO-EB staining showed that the cell apoptosis effect was more obvious on thiocoraline in combination with cisplatin. The Western blot showed that the expressions of the protein Bax,p53,p21 were significantly up-regulated, and the Bcl2 was significantly down-regulated. Conclusion:Thiocoraline combination with cisplatin could up-regulate the expression of the protein Bax,p53,p21 and down-regulation the expression of Bcl2 to inhibition the proliferation and promotion apoptosis of cervical cell line c4-1 and Hela.

Objective A method was developed for determination of the total triterpene glycosides in different sea cucumbers.Methods A holostane triterpene glycoside called Echinoside A was taken as the reference standard.Triterpene glycosides were reacted with vanillin and perchloric acid.The sea cucumbers were extracted by 60% ethanol and partitioned between water and n-butanol to gain the total triterpene glycosides.The contents of total triterpene glycosides in 11 kinds of sea cucumbers were determined with the standard curve.And the relationships of the triterpene glycosides content among different sea cucumber species,growth environment,process technique,etc.were discussed by the value of TG/P(triterpene glycosides content /protein content).Results The determination wavelength was confirmed to be 560nm and the standard curve was determined as y-1.3414x-0.0077.The ab-sorbance was of a good linearity in the mass range of 0-0.5mg with R2 =0.9994.The recovery of this method was(99.01?2.82)% and the relative standard deviation was 4.68%.Conclusion The method has been proved to be convenient,reliable and suitable for the analysis of triterpene glycosides in sea cucumbers.

Objective To study the effect of p38 mitogen activated protein kinase (MAPK) pathway inhibitors SB203580 on cell cycle of K562 cell lines and its mechanisms. Methods The expression of mRNA and protein of p38,Cyclin D2,Cyelin E and P27 in K562 cell lines treated with SB203580 were detected by retrotranscription polymerase chain reaction (RT-PCR) and Western blotting, respectively. Cell cycle was determined by flow eytometry (FCM). Results The expressions of mRNA and protein of p38, Cyclin D2 and Cyclin E in K562 cell lines treated with SB203580 were decreased and the expression of p27 was increased.The percentage of cells in G0/G1 phase was increased and was decreased in S phase. There was a significant difference as compared with K562 cell lines before treated with SB203580. Conclusion SB203580 can affect cell cycle regulatory proteins by p38 pathway and eventually inhibit proliferation of K562 cells.

A multi-residue analysis method was developed for the determination of 38 kinds of pesticides in nuts (almonds, peanuts, cashew nuts and walnuts) by QuEChERS-ultra-high performance liquid chromatography-tandem mass spectrometry.The pesticide residues were extracted with acetonitrile.The extract was cleaned up with PSA, C18 and Oasis PRiME HLB, and then analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode.External standard method was employed to quantify.The limits of detection (LODs, S/N=3) of this method were between 0.01 and 10 μg/kg, and the limits of quantitation (LOQs, S/N=10) were between 0.05-20 μg/kg.All of the tested pesticides showed good linear relationship (r>0.991).The practical samples were determined at three spiked levels and the average recoveries were between 51.0% and 126.0%.The RSDs were less than 20%.This method was simple, sensitive and accurate, and could be used for the routine analysis of pesticide residues in nuts.

Objective:To investigate the effect of chronic ethanol consumption on sensory information transmission in the cerebellar molecular layer and reveal the mechanism of chronic alcoholism on sensory information transmission and integration in the cerebellar cortex.Methods:Fifty healthy male ICR mice aged 6-8 weeks were randomly divided into saline group(control group)and ethanol consumption group(alcohol group) according to the random number table, with 25 mice in each group.The mice in alcohol group were injected intraperitoneally with 20% ethanol daily, while the mice in control group were injected with the same dose of normal saline. All mice were injected intraperitoneally once a day for 28 days.Through electrophysiological technology, patch-clamp amplifier and data acquisition software were used to record the changes in cerebellar molecular layer field potential of mice in the alcohol group and control group induced by sensory stimulation.Clampfit 10.3 software was used to record and analyze the electrophysiological data. SPSS 22.0 software was used for statistical analysis. Paired t-test and one-way ANOVA were used to analyze the differences before and after treatment. Results:After giving the stimulation of wind blowing, the amplitude of P1 in alcohol group was significantly higher than that in control group ((121.31±3.5)%, (97.2±2.7)%; t=26.08, P<0.05), and the area under the P1 curve (AUC) of the alcohol group was significantly lower than that of the control group ((127.1±4.2)%, (102.2±3.5)%; t=22.95, P<0.05). There was no significant difference in N1 amplitude between the two groups (P>0.05). When L-NNA, an inhibitor of nitric oxide synthase, was perfused into the brain surface of mice, the amplitude of P1 in alcohol group was significantly lower than that before administration ((76.2±4.8)%, (103.5±3.6)%; t=22.60, P<0.05), but there was no difference of the amplitude of P1 before administration and after elution ((101.5±4.6)%) ( t=1.70, P>0.05). After the L-NNA was perfused, the AUC of P1 was significantly lower than that before administration((72.4±5.6)%, (102.7±2.66)% ( t=24. 58, P<0.05), and there was no significant difference between before administration and after elution( (100.6±3.5)%, t=1.81, P>0.05). When L-NNA was perfused into the brain surface of mice, the amplitude of P1 in control group was (104.3±1.6)% and it had no differences compared with before administration(102.2±5.6)%, t=1.84, P>0.05) and after elution(102.5±4.5)%, t=1.92, P>0.05). And the AUC of P1 in control group after perfused L-NNA had no differences compared with before administration(103.5±2.6)%, (102.5±4.6)%) and after elution((101.9±3.7)%, t=0.99, 1.81, both P>0.05). When the mouse brain surface was perfused with NO donor SNAP, the amplitude of P1 in the control group was significantly higher than that before administration( (128.2±3.4)%, (103.5±2.6)%; t=28.89, P<0. 05) and there was no difference between before administration and after elution( (105.4±4.2)% , t=1.93, P>0.05). The AUC of P1((125.4±4.4)%) was higher than before administration((104.3±4.6)% , t=16.60, P<0.05) and there was no difference between before administration and after elution(103.5±4.2)%, t=0.65, P>0.05). Conclusion:Chronic ethanol consumption significantly enhances the inhibitory response, and the enhancement of inhibitory components stems from the activation of the NO signaling pathway.

Objective To analyze the clinical and molecular features of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in neonates and to investigate their antibiotic resistance profiles.Methods A total of 35 invasive CA-MRSA strains were collected from six hospitals in 2014.Multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing and spa typing were used to analyze these isolated CA-MRSA strains.In vitro antibiotic susceptibilities of those strains to 15 antibiotics were analyzed by using agar dilution method.Results Up to 88.6% patients were late-onset infection and septicemia (24, 68.5%) was the most common infection among the 35 cases.A total of 16 patients (45.7%) suffered from complications.Caesarean section and premature birth were risk factors for invasive CA-MRSA infection.ST59-MRSA-SCCmecⅣa-t437 (14, 40%) was the most predominant CA-MRSA clone, followed by ST59-MRSA-SCCmecⅤ-t437 (13, 37.1%).The incidence of severe complications caused by ST59-MRSA-SCCmecⅤ-t437 was higher than that caused by ST59-MRSA-SCCmecⅣa-t437 (P<0.05).Up to 85.7% of the isolated CA-MRSA strains were multidrug-resistant strains.Conclusion This study shows that neonatal invasive CA-MRSA infections mainly result in septicemia and are often accompanied by complications and involve multiple organs.Multidrug-resistant CA-MRSA strains are prevalent in neonates.ST59-MRSA-SCCmecⅣa-t437 is the predominant clone causing neonatal invasive CA-MRSA infection.

This article was aimed to rapidly analyze chemical composition in A loe Barbadensis Mill, and to compare the chemical composition of commercial aloe vera medicinal materials with that of fresh aloe yellow exudate. An opti-mized liquid chromatography-mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF) method was applied for the analysis of commercial aloe vera medicinal materials and fresh aloe yellow exudates. The Agilent TC-C18 column (4.6 í 250 mm, 5 m) was used. The gradient elution was a solvent system of water(A)-methanol(B). ESI source was operated in both positive and negative ion modes. The results showed that chromones, pyrones, naphthalene deriva-tive, anthrones and anthraquinones were separated successfully, 30 compounds were characterized by the comparison of characteristic MS/MS fragment ions data with the literature. The diagnostic fragmentation patterns of different chemical compositions were also discussed on the basis of EST-IT-TOF MS data. It was concluded that the chemical composition of commercial aloe vera medicinal materials were significantly different from that of fresh aloe yellow ex-udate in terms of types and contents: the former one mainly contains isoaloeresin D and aloin, and few aloesin; but the latter is mainly composed of aloesin and aloin, and the content of aloesin is the highest. The LCMS-IT-TOF analysis can be used to rapidly obtain rich structural information of different chemical compositions, which improves the efficiency of qualitative analysis of chemical composition, and is of great significance to the quality control, eval-uation and the utilization of A loe Barbadensis Mill.