Microsatellite instability(MSI)was defined according to the frequency of positive findings in a panel of MSI markers.High frequency MSI(MSI-H)was the phenotype in which repeat sequences were extraordinarily unstable, and was considered to be the bona fide phenotype of DNA mismatch repair defection. However base substitutions in some well studied oncogenes or tumor suppressors were reported to be uncommon in MSI-H tumors. To explore this obvious contradiction, the relationship between MSI and KRAS gene mutations were studied in a panel of 76 human colorectal carcinomas, the whole exon of MLH1 and MSH2 were sequenced for MSI-H tumors. KRAS gene mutation was confirmed by similar frequencies in tumors of different MSI status. Intriguingly, all of the KRAS mutant MSI-H tumors harbored sequence alterations in MLH1gene, which was a key player in DNA mismatch repair system. This implied that in MSI-H tumors carrying MMR mutations, KRAS mutation were frequently and almost exclusively occurred. Furthermore, these MMR mutants were uniformly carrying a unique "modification" + "jumping" type MSI, which was different to MSI-H tumors without MLH1 or MSH2 gene mutations. This study shaded lights on the heterogeneity of MSI-H tumors, and implied the connection between "modification" type MSI and DNA mismatch defection.

Objective To develop and evaluate a TaqMan Real-time PCR method for the detection of pathogenic Leptospira species.Methods rrs gene of part fragment on 16S rRNA was used to design primers and TaqMan probe.The target gene was cloned into vector pMD19-T in order to make the standard curve and be used for quality control.To determine the specificity and specificity,DNA from Chinese Leptospira strains belonging to 15 pathogenic reference strains,21non-pathogenic reference strains,and 50 different serotypes of pathogenic isolates as well as 27 other micro-organisms were included in this study.Eight serial DNA dilutions from pathogenic Leptospira and DNA from 25 kidney tissues were detected by Real-time PCR and conventional PCR simultaneously.Results A Real-time PCR methodology was developed and optimised.All the pathogenic Leptospira gave a positive amplification.Non-pathogenic Leptospira and all the other micro-organisms were not amplified.The plasmid sensitivity of Real-time PCR and conventional PCR were 10 copy/μl and 104 copy/μl respectively.The DNA sensitivity of Real-time PCR and conventional PCR were 100 fg/μl and 1 ng/μl respectively.The kidney tissue detection of the two methods appeared to be exactly the same.Conclusion This research project successfully developed a Real-time PCR methodology with better sensitivity and specificity for the identification of pathogenic Leptospira,using the rrs gene.

OBJECTIVETo construct cDNA subtracted libraries from gastric dysplasia and further screen differentially expressed genes.

METHODSRelatively pure dysplasia and normal tissue were procured by manual microdissection, and amplified by cDNA-PCR, which was used to carry on for suppression subtractive hybridization (SSH). Subtracted cDNA fragments were linked with vector, cloned, screened, sequenced, and made homologous search. Differentially expressed fragments were verified by dot hybridization.

RESULTSTwo subtracted cDNA libraries were constructed. Among 26 sequenced clones, 15 fragments corresponded to known genes, 3 fragments were known EST and 8 fragments were unknown EST (GenBank BQ164614-BQ164616, BQ291516-BQ291520). Fifteen fragments were verified to be differentially expressed in gastric dysplasia.

CONCLUSIONSSubtracted cDNA libraries from gastric dysplasia are constructed using combination of microdissection-cDNA PCR and SSH setup in our laboratory. Some fragments have been screened and verified to help to search for novel associated genes with gastric carcinogenesis.

Cloning, Molecular ; DNA, Complementary ; genetics ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Gene Library ; Humans ; Microdissection ; Nucleic Acid Hybridization ; methods ; Polymerase Chain Reaction ; Precancerous Conditions ; genetics ; pathology ; Sequence Analysis, DNA ; Stomach Neoplasms ; genetics ; pathology

OBJECTIVETo screen and analyze the important associated genes in different stages of gastric cancer.

METHODSUsing suppression subtractive hybridization (SSH) to screen differentially expressed genes; detecting the expression of genes in different stages of gastric cancer with dot blot hybridization; and verifying the results with semi-quantitative reverse transcriptase-polymerase chain reaction(RT-PCR).

RESULTSTwenty-six differentially expressed gene fragments were obtained by means of SSH. Among them,24 were known genes, 1 was a new expressed sequence tags(EST), and 1 was a hypothetical gene. The results of dot blot hybridization demonstrated that the expressions of Annexin A2, RPS29, RPS12 etc. in dysplasia were higher than those in normal mucosa; the expressions of RPS12 etc.in early cancer were higher than those in normal mucosa;the expressions of cytochromosome C oxidase II, ferritin light chain, RPS12 etc. in advanced gastric cancer and lymph node metastases were consistently higher than those in normal mucosa. The expression of proteasome 26S subunit gene in advanced gastric cancer was higher than that in normal mucosa. The expression of RPS12 was consistently higher in different stages of gastric cancer. It was demonstrated by RT-PCR that the expression of RPS12 in gastric cancer was higher than that in normal mucosa.

CONCLUSIONThe authors have identified some important genes that might be involved in the carcinogenesis and progression of gastric cancer, and RPS12 may play more important roles in gastric cancer.

Gene Expression Profiling ; methods ; Gene Expression Regulation, Neoplastic ; Genetic Testing ; methods ; Humans ; Nucleic Acid Hybridization ; methods ; Reverse Transcriptase Polymerase Chain Reaction ; Stomach Neoplasms ; diagnosis ; genetics

OBJECTIVETo identify gene expression patterns in distinct stages of intestinal-type gastric cancer(GC).

METHODSGene expression patterns of distinct stages of intestinal-type GC samples from 3 patients were compared with cDNA microarray, which contained 576 genes. There were 506 target genes, which included 51 genes identified from our previous experiment with suppression subtractive hybridization(SSH) and other 455 genes chosen for their important roles in cancers. Hierarchical clustering was performed to clarify genes in association with distinct stages of GC.

RESULTSOne hundred and eighty-one differentially expressed genes with average Cy5:Cy3 ratios higher than 2.0 or lower than 0.5 in at least one stage of GC were identified by cDNA microarray. Among them, 48 genes were up-regulated and 133 down-regulated. Hierarchical clustering analysis separated the differentially expressed genes in different stages of GC into 5 main characteristic groups. Some important differentially expressed genes in different stages of GC were identified, such as SEC23IP, LIPF, ES(BQ291520), SLC5A1, PG(encoding similar to pepsin A precursor), CXCR4, DICER1, SH3GL2, and IGF2R.

CONCLUSIONThe differentially expressed gene patterns and some important genes were identified, which might be useful in further study on carcinogenesis, progression and metastasis of intestinal-type GC.

DNA, Neoplasm ; analysis ; Gene Expression ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Gene Library ; Humans ; Microarray Analysis ; Nucleic Acid Hybridization ; Oligonucleotide Array Sequence Analysis ; Stomach Neoplasms ; genetics ; metabolism ; Transcription, Genetic

Bufonis Venenum, an animal medicinal material, is widely used for treating cardiovascular diseases and pain induced by rheumatics or malignant tumors. In view of the high activity and high toxicity, it is of great significance to pay attention to the quality control of Bufonis Venenum to ensure the safety and effectiveness of its preparations. China's drug standards involve 102 preparations(474 batch numbers) containing Bufonis Venenum approved for sale, including 14 preparations in the Chinese Pharmacopoeia(2020 edition) and 68 preparations in the standards issued by the Ministry of Health Drug Standard of the People's Republic of China. Bufonis Venenum is mostly used in pill and powder preparations in the form of raw powder, with the main functions of clearing heat, removing toxin, relieving swelling and pain, replenishing qi, activating blood, opening orifice, and awakening brain. Except the high level of quality control for Bufonis Venenum in the preparations in the Chinese Pharmacopoeia(2020 edition), the quality control standards of Bufonis Venenum in other preparations are low or even absent. Therefore, it is urgent to conduct research on the improvement of quality standards for the preparations containing Bufonis Venenum. This study retrieved the reports focusing on the quality evaluation and quality control of the preparations containing Bufonis Venenum from CNKI, PubMed, and Web of Science. Qualitative and quantitative analysis methods for 64 preparations containing Bufonis Venenum have been reported, mainly including thin-layer chromatography, HPLC fingerprint, and multi-component content determination. The index components mainly involved bufadienolides, such as gamabufalin, arenobufagin, bufotalin, bufalin, cinobufagin, and resibufogenin. According to the literature information, this paper suggests that attention should be paid to the correlations between the analysis methods and detection indexes of medicinal materials, decoction pieces and preparations, the monitoring of indole alkaloids, and the content uniformity inspection for further improving the quality standards for the preparations containing Bufonis Venenum.
Animals ; Humans ; Bufonidae ; Powders ; Bufanolides/pharmacology* ; Quality Control ; Chromatography, High Pressure Liquid ; Pain/drug therapy*