ABSTRACT
Food-borne pathogenic bacteria seriously threaten public health. Based on the mechanism of fluorescence resonance energy transfer (FRET), a ratiometric fluorescence biosensor was constructed by integration of Exo III-based signal amplification strategy. The Cy3 labeled R1-DNA firstly hybridized with Cy5 labeled R2-DNA to form duplex of R1/R2. Cy3 showed a low fluorescence response while Cy5 showed a high fluorescence response. The addition of target pathogenic bacterial gene (Lac Z gene) could de-hybridize the R1/R2,resulting in the fluorescence decreasing of Cy5 and the fluorescence recovering of Cy3. Under the assistance of Exo III, the signal change was further amplified. The detection of limit reached as low as 5.29 pmol/L. The linear detection range was from 10 pmol/L to 2000 pmol/L. The developed ratiomtric detection strategy significantly reduced the possibility of false-positive and false-negative detection results.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the value of real-time fluorescence quantitative PCR in the diagnosis of chromosome anepuploidy.</p><p><b>METHODS</b>ABCC4 gene on chromosome 13, TYMS gene on chromosome 18, DSCR3 gene on chromosome 21, HPRT2 gene on chromosome X, and SRY gene on Y chromosome were used as the target genes, with GAPDH gene on chromosome 12 as the control gene. Using double-standard curve fluorescent relative quantitative PCR method with SYBR Green as the fluorescent dye, the gene expression levels were detected and the results were compared with those of karyotype analysis.</p><p><b>RESULTS</b>The ratio of the target gene on chromosome 13 to the control gene showed a significant difference between the normal karyotype group (0.90 - or + 0.31) and trisome group (1.39 - or + 0.12, P=0.003), and the genes on chromosome 18 (1.07 - or + 0.44 vs 1.66 - or + 0.12, P=0.000) and chromosome 21 (0.84 - or + 0.27 vs 1.73 - or + 0.54, P=0.000) showed similar results. The expression of the genes on the X chromosome showed no significant difference between 45, X group and 46,XY group (0.62 - or + 0.12 vs 0.63 - or + 0.25, P=0.965), nor between 46, XX group and 47,XXY group (1.32 - or + 0.37 vs 1.20 - or + 0.35, P=0.326), while a significant difference was noted between the single copy X (including 45,X and 46,XY) and two copies X (46,XX and 47,XXY) (0.63 - or + 0.23 vs 1.26 - or + 0.36, P=0.000). The expression of the target gene on the Y chromosome was not detected in normal females (46,XX), and a significant difference in the expression was found between normal male group (46,XY) and 47,XYY group (1.57 - or + 0.54 vs 3.08 - or + 0.15, P=0.003).</p><p><b>CONCLUSION</b>SYBR Green I real-time fluorescence quantitative PCR can be used for the purpose of rapid diagnosis of chromosome aneuploidy.</p>
Subject(s)
Female , Humans , Male , Aneuploidy , Chromosome Disorders , Diagnosis , Chromosomes, Human, Pair 13 , Genetics , Chromosomes, Human, Pair 18 , Genetics , Chromosomes, Human, Pair 21 , Genetics , Fluorescence , Organic Chemicals , Reverse Transcriptase Polymerase Chain Reaction , Methods , Trisomy , DiagnosisABSTRACT
<p><b>OBJECTIVE</b>To investigate the value of fetal chromosomal karyotype analysis in cases of early spontaneous abortion.</p><p><b>METHODS</b>Chorionic villus specimens obtained from 110 cases of early spontaneous abortion were cultured for karyotype analysis.</p><p><b>RESULTS</b>Of the 110 cases, chorionic villus was successfully cultured in 103 cases (93.7%), and abnormal embryo karyotypes were identified in 52 cases (50.5%). Trisomy was the most frequent embryo karyotype abnormalities in these cases, and chromosomal aberration occurred in 29 cases (52.9%) of the first spontaneous abortion and in 23 cases (42.6%) of repeated abortions. Female fetuses accounted for 75.5% (78 cases) in the spontaneously aborted fetuses and for 67.3% (35 cases) in fetuses with chromosomal abnormalities.</p><p><b>CONCLUSION</b>Embryo chromosomal abnormality is the most important reason of early spontaneous abortion, and karyotype analysis of the villus helps identify the causes of abortion and ensure the success of the next pregnancy.</p>
Subject(s)
Adult , Female , Humans , Pregnancy , Abortion, Spontaneous , Genetics , Pathology , Cells, Cultured , Chorionic Villi , Pathology , Karyotyping , Pregnancy Trimester, First , Trisomy , GeneticsABSTRACT
Objective To analyse the imaging characteristics of solitary pulmonary nodules(SPNs) with the spiral CT, and detection clinical values of the definitive diagnosis to SPNs. Methods 32 cases of SPNs were identified by spiral CT, 9 cases of them were examinated by enhancement scanning. The diffrentical imaging features were analyzed. Results 24 cases were malignant in imaging(18 cases were identified), 8 cases were benign in imaging(6 cases were identified). 15 cases of malignant SPNs by clinical identified were smooth at edge; 6 cases of benign SPNs by clinical identified. 5 cases of them were anomaly;4 cases of them were burr;2 cases of them were bronchial sign and vesiclat sign.6 cases of the SPNs were calcified. 6 cases of SPNs(9 cases with contrasting) were benign in imaging, 3 cases of them were malignant in imaging. Conclusion The differential diagnostic of SPNs is difficult by spiral CT, but enhancement scanning and epidemiology combined with spiral CT is very valuable for definitive diagnosis.