In this study, loop-mediated isothermal amplification (LAMP) assay in conjunction with calcein for visualized detection of Mycobacterium tuberculosis (MTB) was established. Firstly, four LAMP primers were designed according to the region of 16S rDNA sequences of MTB. Secondly, clinical sputum samples were collected, decontaminated and their DNA was extracted. Thirdly, standard MTB strains were used to evaluate the specificity and sensitivity of LAMP. At the same time, electrophoresis was used for products detection and calcein was used for visualized verification. At last, Chi-squared test function in SPSS 17.0 software was used for consistency evaluation of LAMP assay as compared with the gold standard (culture method). Results showed that there was no nonspecific amplification appeared in the specificity assay and the detection limit was 10 copies/tube in the sensitivity assay. In addition, visualized method by calcein had a comparable sensitivity with that of electrophoresis method. After evaluation of clinical practicability, the sensitivity of LAMP was calculated as 94.74% and the specificity was 90%, respectively. And Chi-squared test showed that LAMP and culture method had no statistic difference, and the two methods were in good consistency (P>0.05). In conclusion, LAMP assay introduced in our study has the characteristics of high efficiency and visualized detection so that this technique has great application prospects in the resource-limited environment, such as work field and primary care hospitals.
【Abstract】ObjectiveTo study the effect of transfection with antisense DNMT3b gene eukaryotic expression vector on the expression of DNMT3b gene in human cholangiocarcinoma cell line QBC-939. MethodsThe constructed antisense DNMT3b gene eukaryotic expression vector was transfected into the human cholangiocarcinoma cell line QBC-939 by using lipofectamine transfection reagents, and positive cell clones were obtained by using G418 selection after transfection. Whether the constructed recombinant vector was transfected into QBC-939 cells successfully was confirmed by amplifying the exogenous neoR gene with PCR method. The expression of DNMT3b gene mRNA and protein were detected by semi-quantitative RT-PCR and FCM methods respectively. ResultsFollowing the transfection of antisense DNMT3b gene eukaryotic expression vector, the mRNA level of DNMT3b gene in QBC-939 cells of human cholangiocarcinoma decreased from 0.956±0.053 to 0.209±0.023, and the protein level of DNMT3b gene also decreased from (75.38±3.22)% to (29.87±3.46)%. There were very significant differences on the expression levels of DNMT3b gene between non-tranfections group and the antisense DNMT3b gene eukaryotic expression vector transfection group (P＜0.01). ConclusionTransfection with antisense DNMT3b gene eukaryotic expression vector significantly reduces the expression level of DNMT3b gene in human cholangiocarcinoma cell line QBC-939, and this study may provide a valid tool and method to investigate the function of DNMT3b gene and its role in cholangiocarcinoma.
【Abstract】ObjectiveTo review recent studies on Muir-Torre syndrome (MTS) and to improve the knowledge about MTS.MethodsThe literatures in recent years on clinic and gene research of MTS were reviewed.ResultsMTS was is a rare autosomal-dominant disorder characterized by the predisposition to both sebaceous tumors (or multiple keratoacanthomas) and internal malignancies. Gastrointestinal cancers were the most common kind of internal malignancies in MTS patients(61%)，followed by genitourinary cancers(22%). In most cases(56%)，sebaceous tumors appeared after the emergence of internal maliganancy. Both hereditary nonpolyposis colorectal cancer(HNPCC) and MTS were caused by germline mutations in the DNA mismatch repair genes. MTS patients exhibit significantly more mutations in the hMSH2 than in the hMLH1. In these cases , both internal and skin tumors showed the characteristic of high microsatellite instability(MSI).ConclusionThe presence of sebaceous tumors(or multiple keratoacanthomas) necessitates the search for internal malignancies. It is mandatory that patients with MTS, as patients with HNPCC, should be regularly followed up to search new malignancies. Evaluation and monitoring of the family members of patients are also necessary. The patients and their families should be counseled for genetic test. Sequencing the hMSH2 gene should be the prior selection of further examinations when clinical manifestations, history and laboratory tests suggest MTS.
ObjectiveTo explore the relationship between aberrant promoter CpG islands methylation status of E-cadherin gene and hepatocarcinogenesis, and to assess its significance in clinical early diagnosis of hepatocellular carcinoma (HCC). MethodsSurgically resected specimens, among which cancerous and corresponding noncancerous liver tissues from 34 HCC patients, 10 liver cirrhosis from patients without HCC and normal liver tissues from 4 accidental deaths, were collected in West China Hospital. Breast cancer cell line MDA-MB-435 with promoter CpG islands hypermethylation of E-cadherin as positive control was gained from the Cell Bank of Chinese Academy of Sciences in Shanghai. The methylation status of promoter CpG island of E-cadherin gene was detected by nested methylationspecific polymerase chain reaction (nested-MSP). ResultsE-cadherin gene promoter CpG islands hypermethylation was found in 61.76% (21/34) of cancerous tissues, in 29.41% (10/34) of noncancereous tissues from the 34 HCC patients and in 50.00% (5/10) liver cirrhosis from patients without HCC. None of the 4 normal liver samples were detected E-cadherin mehylation positive. Moreover, the methylation of E-cadherin gene was significantly more frequent in 34 cancerous than that in corresponding noncancerous liver tissues (Plt;0.05), which had no significant difference between the 10 cirrhotic samples and cancerous or non-cancerous liver tissues (Pgt;0.05). In 34 cancerous samples, with the combination of both biomarkers of E-cadherin methylation and AFP400 (serum AFP level at a cutoff of 400 μg/L), the diagnostic sensitivity of HCC increased to 82.35%. ConclusionsThe aberrant promoter methylation of E-cadherin gene may play a vital role in the development and progression of HCC. Moreover, it might be an early event in hepatocarcinogensis. It is of high value to make further study to confirm the significance of E-cadherin gene methylation in clinical diagnosis and therapy.
ObjectiveTo explore the presence of common genetic alterations in retinoblastoma and to localize the altered genomic regions.MethodsGenetic instability of chromosome 19, 20, 21, 22 and X of 15 microdissected retinoblastoma tumors were analyzed by the loss of heterozygosity (LOH) and microsatellite instability (MSI).ResultsAmong the 15 patients with retinoblastoma, genome instability ［LOH and(or) MSI］ at one or more loci on the 5 chromosomes in 10 (67%), in which the loss of a single allele was more frequent in chromosomes 19 (33%) and 20 (27%) than in the other 3 chromosomes. Highfrequency LOH between D19S902 and D19S571 suggested gene loci in the 19q13 region might be associated with tumor development in retina. According to the result of MSI, MSI occured at least in one subset of retinoblastoma.ConclusionsOur results provide first evidence of LOH in chromosomes 19 and 20 in retinoblastoma and further support the presence of genome instability in retinoblastoma that may play an important role in the tumorigenesis or progression of retinoblastoma.(Chin J Ocul Fundus Dis, 2005,21:28-31)
Objective To explore the feasibility of identifying clonal origin of hepatocellular carcinoma (HCC) by analyzing the mitochondrial DNA D-Loop region variations. Methods Forty-two patients with a total of 112 HCC nodules consequentially hospitalized for radical resection of HCC in the department of hepatobiliary surgery of the First Affiliated Hospital of Guangxi Medical University from April 2004 to August 2007 were included for study group (multinodular HCCs). Control group included 20 cases of HCC (40 samples) hospitalized in the same period that consisted of two sub-groups: control groupⅠconsisted of 16 cases of single nodular HCC that each had two pieces of inconsecutive tumor tissues and control groupⅡconsisted of 4 cases of HCC with portal vein tumor embolus whose tumor tissues and portal vein tumor embolus were collected simultaneously. Normal control included 5 patients who were donors for liver transplantation or underwent liver trauma without any liver disease. Polymerase chain reaction (PCR) and direct sequencing were applied to study the mtDNA D-Loop region. The sequences of multinodular lesions were compared among different groups. Results For all the 42 cases of the study group, basic group variations appeared in 131 sites (131/1 122, 11.7%, the number 1 122 was the length of mtDNA D-Loop) with point mutation in 15 sites, insert in 9 sites, and deletion in 16 sites. And of all the variations in the study group, 98 were polymorphism. In study group, 20 cases were categorized as multicentric occurrence (MO) based on their variant mtDNA D-Loop sequences in each nodule from the same patient. And 22 cases were characterized as intrahepatic metastasis (IM) based on the identical mtDNA D-Loop sequences found in each nodule from the same patient. In all 20 cases in the control group, the inconsecutive tumor tissues or the portal vein tumor embolus and original tumors shared identical mtDNA D-Loop sequences. For the normal control group, basic group variations appeared in 14 sites, and they were all polymorphism including a new polymorphism (NT 479 Agt;G). Conclusions There is a high rate of changes in mtDNA D-Loop region. And our study speculates a novel discrimination of MO and IM origins among multinodular HCCs using PCR and direct sequencing of the mtDNA D-Loop sequences.
Purpose
To investigate mitochondrial DNA (mt-DNA) mutations in optic neuritis of unknow reason (ONUR) and to assess the pathogenic and differential diagnostic values of screening for mt-DNA mutations in ONUR.
Method
Thirty patients with ONUR were screened for mt-DNA mutations by using SSCP,mutation-specific primer PCR and sequencing.
Results
mt-DNA mutations were found in 12 out of the thirty patients.All of the mutations were at 11778 position,but no one at 3460 and 15257.
Conclusions
Quite a number of patients (12/30,40%) with ONUR were caused actually by mt-DNA mutation．Screening for mt-DNA mutation in these patients has a pathogenic and differential diagnostic significance.
(Chin J Ocul Fundus Dis,2000,16:78-79)
Objective
To investigate the histological origin, diagnosis, differential diagnosis and treatment of thyroid carcinoma showing thymus-like differentiation (CASTLE).
Methods
Five patients with thyroid CASTLE were adopted by surgical resection and postoperative radiotherapy, and the CD5, CD117, CK5/6, P63, thyroid transcription factor-1 (TTF-1), carcino-embryonic antigen (CEA), calcitonin (CT), Ki-67, chromogranin A (CgA), thyrobolulin (Tg), peroxisome proliferator activated receptorγ (PPAR-γ), sodium iodide symporter (NIS), and thyroid stimulating hormone receptor (TSHR) were detected in tumor tissues by immunohistochemistry S-P method and v-raf murine sarcoma viral oncogene homolog B1 (BRAF)V600E gene and telomerase reverse transcriptase (TERT) promoter mutations were detected by DNA sequencing. Eight cases of poorly differentiated thyroid carcinoma and 6 cases of anaplastic thyroid carcinoma were adopted by comprehensive comparative analysis.
Results
Thyroid CASTLE tumor cells showed the positive expression of CD5, CD117, CK5/6 and P63, and the negative expression of TTF-1, CT, CgA, Tg, PPAR-γ, NIS and TSHR. There were partly positive expression for CK5/6, P63, TTF-1, CgA, Tg, NIS and TSHR, and negative expression for CD5 and CD117 in the poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma. The BRAFV600E gene and TERT promoter mutations were not detected in thyroid CASTLE, and the BRAFV600E gene mutations were also not detected in the poorly differentiated thyroid carcinoma and anaplastic thyroid carcinoma. Four cases of poorly differentiated thyroid carcinoma showed the TERT promoter mutations (4/8) included 3 cases with C228T and 1 case with C250T. Two cases of anaplastic thyroid carcinoma showed the TERT promoter mutations (2/6) included 1 case with C228T and 1 case with C250T. There was no recurrence and metastasis after 3–47 months (an average of 25.6 months) of followed-up in thyroid CASTLE patients.
Conclusions
The histological origin of thyroid CASTLE may be not related to the thyroid. There is important clinical value to combined detection of CD5, CD117, P63, TTF-1, Tg, NIS, and TSHR for the diagnosis and differential diagnosis of thyroid CASTLE. The further study still need for the diagnosis and differential diagnosis of thyroid CASTLE according to the detection of BRAFV600E and TERT promoter mutations.
ObjectiveTo explore the clinical significance of promoter hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT) in cholangiocarcinoma. MethodsPromoter methylation status of MGMT gene and expression of MGMT protein were detected in cholangiocarcinoma by methylationspecific PCR and immunohistochemical staining, respectively. ResultsAberrant methylation of MGMT gene was detected in 17 patients (47.2%). Twentyone cases showed negative immunoreactivities. Of 21 patients with negative MGMT expression, 14 patients had aberrant methylation of MGMT gene. In 15 patients with positive MGMT expression, aberrant methylation of MGMT gene was only found in three cases. There was a negative correlation between promoter methylation status of MGMT gene and the expression of MGMT protein (rs=-0.816, Plt;0.05). Promoter methylation status of MGMT gene was related to depth of invasion, degree of differentiation, and TNM stage (Plt;0.05), but not to age of patient, gender, pathological type, and lymph node metastasis (Pgt;0.05). ConclusionsHypermethylation of MGMT promoter is a frequency molecular event in cholangiocarcinoma and may be involved in carcinogenesis. Methylation status of MGMT gene may be used to evaluate malignant degree of cholangiocarcinoma.
ObjectiveTo evaluate diagnostic performance of crithidia luciliae immunofluorescence test (CLIFT), enzyme linked immunosorbent assay (ELISA), linear immunoassay (LIA) and chemiluminescence immunoassay (CLIA) for detection of anti-dsDNA antibodies for systemic lupus erythematosus (SLE).
MethodsA total of 178 sera[SLE (n=86), other systemic rheumatic diseases (n=62), and healthy individual (n=30)], from whom received treatment from July 2012 to June 2013, were tested by 4 different assay kits.
ResultsThe diagnostic performances of four methods for detecting anti-dsDNA antibodies for SLE were ELISA, CLIA, CLIFT and LIA, from higher to lower; while ELISA had the highest sensitivity (67.4%), and CLIA had the highest specificity (95.6%). The three test methods (ELISA, LIA, CLIA) had almost perfect concordance with the comparison method (CLIFT, Kappa >0.8). With cut-off values set at 95% of specificity, there was no statistical difference of sensitivity between ELISA and CLIA (58.1%, 60.5%; P>0.05).
ConclusionFour assays can be used for the clinical detection of anti-dsDNA antibodies, and the results have an almost perfect concordance. Different assays show various performances depending on the methods and cut-off values used.
