BACKGROUND: The particular bystander effect of suicide gene can remarkably kill tumor cells. Meanwhile, it can be used together with radiotherapy as well as immune gene therapy, and overcome the defect of low gene transduction efficiency.Cytosine deaminase (CD) can generate a powerful bystander effect.OBJECTIVE: To observe the effect of a eukaryotic expression plasmid plRES2-AcGFP1-CD mediated by liposome transfected into bone marrow mesenchymal stem cells (BMSCs) and its gene expression.DESIGN, TIME AND SETTING: A cytologic experiment at genetic level was performed at Research and Development Center of Stem Cell and Tissue Engineering, Dalian University of Technology from May to December 2007.MATERIALS: A total of 6 C57BL mice of SPF degree and weighing 18-20 g were used for separation and culture of BMSCs.Escherichia coli DH5a was provided by Research and Development Center of Stem Cell and Tissue Engineering, Dalian University of Technology. Lipofectamine~(TM) 2000 was provided by Invitrogen, China.METHODS: The DNA plasmids were extracted from transformed Escherichia coli DH5a. plRES2-AcGFP1-CD plasmid was identified by BamHI/Xhol double digestion. The BMSCs derived from mouse femur and tibia were cultured and purified by adhesion method in vitro. Signal cell suspension prepared by BMSCs of the third generation was cultured by adding fluorescence-labeled CD44, CD45, CD90 and CD105 antibodies. BMSCs of the third generation were transfected by LipofectamineTM 2000 mediation.MAIN OUTCOME MEASURES: Identification of recombinant plasmids; the expressions of surface markers on BMSCs were detected by flow cytometry; the expressions of cytosine deaminase gene were observed at 36 and 48 hours after transfection under fluorescent inverted microscope.RESULTS: After agarose gel electrophoresis, a band appeared at 1.0-1.5 kb of the digested products of plRES2-AcGFP1-CD plasmids, and the band was accorded with the length of cytosine deaminase gene in the length. Flow cytometry demonstrated that the cells were negative for CD45 but positive for CD44, CD90 and CD105. Fluorescent inverted phase contrast microscope suggested that at 36 hours after plRES2-AcGFP1-CD gene transfection an expression of green fluorescent protein was found in the BMSCs; additionally, at 48 hours after transfection, the expression of green fluorescent protein remained and the intensity was remarkably increased.CONCLUSION: The liposome-mediated plRES2-AcGFP1-CD gene successfully expressed in BMSCs, and the expression peaked at 48 hours after transfection.

The metabolism of thyroid hormone changes during pregnancy. Subclinical hypothyroidism during pregnancy may adversely affect the pregnancy outcomes and neuropsychological development of child, controversially. The diagnostic criteria of subclinical hypothyroidism during pregnancy need to be specific. It is important to figure out when should pregnancy with subclinical hypothyroidism be treated and what is the specific goal of the treatment.

AIM: In this research, the apoptosis mechanism in human umbilical vein endothelial cells (HUVEC) exposed to increasingly high Hcy concentrations was investigated by examining the intracellular signaling pathways. METHODS: HUVEC were cultured and pretreated with Hcy. Twenty-four h after Hcy treatment, cell apoptosis was detected by Annexin V and DNA ladder analysis. Caspase3 and c-IAP1/2 mRNA expression were examined using reverse transcription-polymerase chain reaction (RT-PCR) and protein expression detected by Western blotting. The activation of caspase 3 was measured with the specific substrate DEVD-AMC. RESULTS: Hcy (0.3 mmol/L) induced apoptosis of HUVEC. Caspase 3 mRNA and protein expressions increased and activation enhanced with the concentration of increasing Hcy, but c-IAP2 mRNA and protein expression decreased. CONCLUSION: Hcy induces apoptosis of HUVEC in vivo by activating caspase 3 and inhibiting protein c-IAP-2 mRNA and protein expression.

Objective To understand the Salmonella detectability in the laboratory animal testing laboratories, im-prove the level of detection for the quality of laboratory animals, by means of laboratory animals Salmonella proficiency tes-ting program.Method According to the proficiency testing program approved by CNAS, freeze-dried animal stool samples containing Salmonella bacteria and interference bacteria were prepared, and through stability and homogeneity tests quali-fied as proficiency testing samples.The randomly numbered samples were issued to the participating units by cold-chain transportation, and attached work instructions.The original reports and copies of the tests should be submitted on time.The sample results consistent with the results of the pretested results were considered as satisfactory, and the results inconsistent or fails to submit were judged as unsatisfactory.Results A total of 30 laboratories from 20 provinces and cities nationwide participated in this proficiency testing programs for Salmonella, including 28 ( 93.3%) laboratories with satisfactory re-sults, and two laboratories unsatisfactory ( 6.7%) .29 laboratories used separate culture methods, and two laboratories used PCR method.Conclusions The laboratory animal quality inspection agencies have good detection ability for Salmo-nella.The implementation of the capacity verification plan can well reflect the detection level of laboratories.

Objective To verify the detection ability of experimental animal quality detection laboratories in China for Staphylococcus aureus.Methods The testing samples for Staphylococcus aureus detection were prepared by bacterial culture, homogeneity test and stability test, according to the study plan approved by CNAS.Then the samples and operation instruction were sent to the participant laboratories.The detection reports from these laboratories should be submitted before the deadline expires, and the collected data were summarized and analyzed.Results There were 28 laboratories which joined to this test plan.Among them 22 laboratories ( 78.57%) achieved satisfactory test results, and six laboratories (21.43%) had unsatisfactory test results.27 Laboratories used the national standard detection assay, while only one labo-ratory used PCR assay.Conclusions Most of experimental animal quality testing laboratories in China have sufficient pro-ficiency in detection of Staphylococcus aureus.The obtained information are very helpful for the laboratory ability verification testing in future.

Objective Through the proficiency validation of testing of mammalian orthoreovirus 3 (Reo3)antibody in laboratory mice, to investigate the capacity of experimental animal quality control laboratories, so as to improve the de-tection capacity.Methods According to the program approved by CNAS, serum samples after calibration were tested for stability and homogeneity, and numbered randomly.The random samples were issued to the participant laboratories with the Standard Operation Procedure( SOP) .The participants must submit the test reports and original records in time.The feed-back results were judged by the concordance rate with the anticipated results.Results 27 laboratories from 17 provinces were enrolled in this evaluation project, all of them submitted detection results on time.Results All the 27 laboratories were marked as pass or excellent, with a pass rate of 100%.ELISA was used in 26 laboratories, and immunofluorescence assay was used in one laboratory.Conclusions The ability for detection of Reo3 antibody in laboratory mice in animal test laboratories is high.The implementation of proficiency testing can reflect the inspection level of quality control laborato-ries.

Objective To explore the effect of Ginkgo biloba extract (EGb761) on apoptosis of K-ras mutational human colon cancer cells DLD1(DLD1/G13D)and its mechanism. Methods Human colon cancer cell lines DLD1/G13D and DLD1 with K-ras wild type(DLD1/WT)were cultured in vitro,the cell proliferation and apoptosis after 24 h of EGb761 were measured. Proteins involved in related signal pathway were detected by Western blot or ELISA. Results EGb761 reduced cell proliferation and induced cell apoptosis in a concentration-dependent manner in DLD1/WT and DLD1/G13D cells. EGb761 downregulated the expression of RIP1, impaired the phosphorylation of IκB and decreased the level of NF-κB in DLD1/WT and DLD1/G13D cells[DLD1/G13D: (24±4)%, DLD1/WT: (29±9)%(P<0.05). Conclusion EGb761 restrains the proliferation and induces the apoptosis of DLD1/WT and DLD1/G13D cells. The mechanism may be related to the degradation of RIP-1 and inhibition of activation of NF-κB signaling pathway.

Objective To acquire the prevalence and molecular identification data on Syphacia muris and provide reference for the revision of national standard. Methods 923 batches of 5199 SPF animals ( including one batch of 5 monkeys, 3 batches of 25 mini?pigs, 28 batches of 55 rabbits, 13 batches of 248 hamsters, 37 batches of 198 guinea pigs, 93 batches of 459 rats, 742 batches of 4179 mice, 5 batches of 25 chickens and one batch of 5 ducks) and 145 batches of 1389 clean animals ( including one batch of 3 rabbits, 4 batches of 31 hamsters, 16 batches of 157 guinea pigs, 32 batches of 268 rats and 92 batches of 930 mice ) came from 50 different manufactures in China. Direct microscopy real?time dynamic video recording techniques in combination with morphological identification method were applied to screen the Syphacia muris infestation. A multiple polymerase chain reaction ( multiple?PCR ) testing of the isolate based on amplification of the conserved portions of the Syphacia muris internal transcribed spacer (ITS), 28S ribosomal RNA (28S rRNA), NADH dehydrogenase subunits 1 (nad1) and cytochrome c oxidase subunit 1 (cox1) genes, and the molecular sequencing of the multiple?PCR amplicons was used to confirm the Syphacia muris infection. Results Syphacia muris eggs, larvae and adults were detected by using direct microscopy real?time dynamic video recording technique. Syphacia muris were detected based on the morphology and size of ovum, larvae, and female and male adult worms. Multiple?PCR and sequencing were performed to identify ITS, 28S rRNA, nad1 and cox1 genes of DNA extracted from the single egg, larva and adult parasite Syphacia muris. This approach allowed the specific identification with no amplicon being amplified from heterogeneous DNA samples, and sequencing confirmed the identity of the amplified sequences. Molecular characterization by multiple?PCR amplification and sequencing of the ITS, 28S rRNA, nad1 and cox1 genes demonstrated the presence of Syphacia muris. Multiple?PCR followed by sequencing confirmed 285 of 5199 SPF and 135 of 1389 clean animal samples classified as positive by using direct microscopy real?time dynamic video recording technique in the study as containing Syphacia muris?specific DNA. Comparison of the partial sequences of the ITS, 28S rRNA, nad1 and cox1 genes revealed 100% similarity amongst Syphacia muris from different animals. The prevalence of Syphacia muris infection in SPF and clean animals were 5?5% (285/5199) and 9?7% (135/1389), respectively. Conclusions Direct microscopy real?time dynamic video recording technique, multiple?PCR and sequencing can be used to rapidly detect and accurately identify Syphacia muris. The zoonotic nature of Syphacia muris can be regard as a public health alter, hence the good quality control of animal has an important role in protecting human health and safeguarding people safety. This is the first molecular identification and infection investigation of Syphacia muris in SPF and clean animals in China.

Objective To analyze and evaluate the population genetic quality of 3 subbreeds of China Agricultural University miniature pigs in Beijing.Method According to the local standard DB11/T828.3 -2011, 25 pairs of microsatellite primers were used in 3 subbreeds of China Agricultural University miniature pigs, and software Popgen32 was used to process the data.Results 24 microsatellite loci shared 130, 122 and 138 alleles in the China Agricultural University miniature pigs I, II, III, respectively. The average heterozygosity was 0.6759, 0.5967 and 0.6779, respectively, while the average polymorphism information content ( PIC) was 0.6344, 0.5540 and 0.6403, respectively. The genetic distance between China Agricultural University miniature pig II and III was 0.4251, while the genetic distance between China Agricultural University miniature pig I and II was 0.2084.Conclusions In the 3 subbreeds, China Agricultural University miniature pigs II and III have genetic stability and genetic diversity, and both of which satisfy with the genetic characteristics of closed colony laboratory animal.

Objective To investigate the diagnostic value of superb microvascular imaging(SMI)grading,CT angiography(CTA),and serum small and dense low-density lipoprotein cholesterol(sdLDL-C)in elderly hypertension patients with acute cerebral infarction(ACI).Methods A ret-rospective study was conducted on 180 elderly hypertension patients admitted to our hospital from June 2021 to June 2023,and those admitted due to ACI were assigned into ACI group(95 cases)and those without into non-ACI group(85 cases).The SMI grade,CTA,and serum sdLDL-C level were compared between the two groups.ROC curve was plotted to analyze the diagnostic value of SMI grading and CTA combined with serum sdLDL-C for ACI in patients with hyperten-sion.Multivariate logistic regression analysis was employed to analyze the factors affecting the oc-currence of ACI in the patients.Results The ACI group had significantly larger proportion of hy-perlipidemia,and higher DBP,SBP,and HDL-C,and LDL-C than the non-ACI group(P＜0.05).The proportion of SMI grade 2 and grade 3 and serum sdLDL-C level were also greatly higher[35.79％vs 10.59％,43.16％vs 8.24％,(1.62±0.25)mmol/L vs(1.35±0.19)mmol/L,P＜0.01],and the proportion of SMI grade 0 and grade 1 was lower(11.58％vs 51.76％,9.47％vs 29.41％,P＜0.01)in the ACI group than the non-ACI group.ROC curve analysis showed that the AUC value of SMI grade and CTA combined with serum sdLDL-C in diagnosing ACI in patients with hypertension was 0.934(95％CI:0.897-0.972).Multivariate logistic regression analysis in-dicated that SMI grade,CTA,and sdLDL-C were risk factors for ACI in hypertensive patients(P＜0.01).Conclusion Combination of carotid artery plaque SMI grading,CTA,and serum sdLDL-C has high auxiliary diagnostic value for elderly hypertension patients with ACI.