Objective To identify and isolate the variant gene associated with gastric adenocarcinoma and clone the fragment of variant gene.Methods By arbitrarily primer polymerase chain reaction (AP-PCR), DNA samples from 5 matched gastric adenocarcinoma and non-tumor gastric tissues were analysed. Results The produced AP-PCR profiles were different in each matched gastric adenocarcinoma and non-tumor gastric tissue. One differentiated amplified DNA fragments PW2.2 from a matched gastric adenocarcinoma were cloned. The result of Southern blot hybridization with PW2.2 as a probe showing that this fragment was also found in some other gastric adenocarcinoma samples. Conclusion AP-PCR fingerprinting assay can be used to identify and clone the variant genes associated with gastric adenocarcinoma.
Objective To evaluate the potential of specific mRNA marker keratin 19(K19) to detect micrometastasis by reverse transcriptase polymerase chain reaction (RT-PCR) .Methods One hundred and ninty four regional lymph nodes harvested from 6 cases of benign diseases, 4 cases of breast carcinoma, 5 cases of gastric carcinoma and 12 cases of colorectal carcinoma patients were examined by conventional pathology and amplifying tissue specific K19 mRNA by RT-PCR separately, then the two methods were compared with each other. Results None of the 34 lymph nodes which were pathological metastasis-negative from benign diseases expressed K19 mRNA by RT-PCR, all of the 28 regional lymph nodes which were pathological metastasis-positive from malignant cases showed trains of K19 mRNA by RT-PCR. Of the 132 lymph nodes which were pathological metastasis-negative from malignant cases, 11 lymph nodes were detected with micrometastasis by genetic diagnosis.Conclusion Genetic diagnosis of lymph node micrometastasis is more sensitive than conventional pathology and has diagnostic value and merits further study.
Objective To investigate whether mutations exist in codon 58 and codon 347 of the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa(ADRP)． Methods Point mutations at codons 58 and 347 were detected by restriction endonuclease digestion of exons 1 and 5 amplified by polymerase chain reaction(PCR)．This method was applied to screen genomic DNAs from 57 patients of 38 families with ADRP and 60 normal controls． Results Four patients from one family of ADRP were confirmed to have a point mutation at the second nucleotide of codon 58,and 6 patients from two families of ADRP were found to have a mutation at codon 347．None of these mutations were found in 60 normal subjects． Conclusion It is suggested that molecular genetic heterogeneity exists within ADRP and some subtypes of ADRP are caused by points mutations of the rhodopsin gene． (Chin J Ocul Fundus Dis,1998,14:108-110)
Objective To discuss the changes of c-kit/scf mRNA and protein in guinea pig gallbladder fed on high cholesterol diet. Methods Twenty guinea pigs were divided into two equal groups of 10 each：the control group and lithogenic group. Normal diet and high cholesterol diet was given to each group respectively. The period of stone permeation was six weeks. RT-PCR and Western blot were used to determin the expressions of c-kit and scf mRNA and protein. Results RT-PCR results showed that the expressions of c-kit mRNA（t=6.985，P＜0.01） and scf mRNA （t=6.028， P＜0.01）decreased significantly in lithogenic group compared with the control group. Western blot results showed that the expressions of c-kit protein （t=10.256， P＜0.01） and scf protein （t=9.586， P＜0.01）decreased significantly in lithogenic group compared with the control group. Conclusions The expressions of c-kit/scf mRNA and protein decrease during the formation of cholesterol gallstones in guinea pigs fed on high cholesterol diet. Inhibition of c-kit/scf pathway may play a role in the formation of cholesterol gallstones.
Objective To detect traces of microRNAs (miRNAs) in plasma and assess the expression stability of two common reference genes by stem-loop and poly A polymerase (PAP) real-time quantitative polymerase chain reaction (PCR) method, as miRNAs are the new bio-markers of tumor diagnosis and molecular targeted therapy, and its quantitative research is very important. Methods We extracted miRNAs from plasma of adult Sprague Dawley (SD) rats’ plasma, and detected the expressions of rno-miR-200b-3p and rno-miR-126-3p with stem-loop and PAP real-time PCR quantitative method, with rno-miR-103a-3p and U6 as internal controls. All the results were evaluated by 2△Ct method. Results Compared with PAP method, the stem-loop method reduced Ct value by 2-4 cycles and improved sensitivity by 10 times. In PAP method, the melting curve showed two peaks, a main peak and a small non-specific peak. Yet the melting curve of stem-loop method demonstrated a single specific peak. Furthermore, we validated the stability of internal references in the two real time PCR methods. U6 presented a more stable Ct value than rno-miR-103 in adult SD rats’ plasma samples. Conclusions Stem-loop real-time PCR is recommended as a major way to detect some samples with a low concentration of miRNAs, owing to its high accuracy and sensitivity. However, if a large number of tissue samples is going to be detected, PAP real-time PCR is more suitable and convenient than stem-loop method. U6 is more stable and repeatable than rno-miR-103a-3p as the reference gene to evaluate the semi-quantitative consequence of miRNAs.
Objective To detect and analyse the mutations in rhodopsin gene of members in a family affected by autosomal dominant retinitis pigmentosa (ADRP). Methods Using the polymerase chain reaction (PCR), we amplified exon 1-5 of rhodopsin gene in patients with ADRP,and analyzed it with direct sequence measuement. Results The Gly-182-Asp mutation in the rhodopsin gene was detected in most of affected members of this ADRP family, but no mutation was detected in two affected members and the control ones. Conclusion We cannot regard the Gly-182-Asp mutation in the rhodopsin gene as the pathagenic factor of the ADRP family. It is likely there is a new gene next to the rhodopsin gene. (Chin J Ocul Fundus Dis, 2002, 18: 256-258)
Objective To evaluate the rapid diagnosis of bacterial and (or) fungal endophthalmitis by multiplex polymerase chain reaction (MPCR). Methods MPCR was performed to detect the DNA segment of bacteria and (or) fungi from standard strains and 41 samples of intraocular fluid or vitreous from 38 patients (3 with double eyes and 35 with single), and the results were compared with the cultured bacteria and fungi. Results Five hours after detected by MPCR, bacteria and (or) fungi in 34 out of 41 samples (82.9%) from patients were detected，in cluding bacteria in 26，fungi in 6，and both bacteria and fungi in 2. The positive rate of MPCR was obviously higher than the cultured ones（χ2＝9.60, P＜0.05）. Conclusion With the advantages of rapidity, sensibility, and specificity, MPCR can make for the rapid and definitive diagnosis of bacterial and (or) fungal endophthalmitis. (Chin J Ocul Fundus Dis，2004，20：81-83)