POLYMERASE CHAIN REACTION (PCR) AND REAL TIME PCR (For Detection and Quantification of Nucleic Acid)

2007 ◽  
pp. 267-267
Author(s):  
Dr Chatterjea ◽  
Dr Shinde
2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Subeen Hong ◽  
Seung Mi Lee ◽  
Sohee Oh ◽  
So Yeon Kim ◽  
Young Mi Jung ◽  
...  

AbstractTo examine the detection performance of a peptide nucleic acid (PNA) probe-based real-time time polymerase chain reaction (PCR) assay to detect common aneuploidies. Using amniotic fluid samples, PNA probe based real-time PCR (Patio DEP Detection Kit; SeaSun Biomaterials, Korea) assay was performed. PNA probe was designed to hybridize to similar sequences located on different segments of target chromosomes (21, 18, and 13) and a reference chromosome. Amplification of target sequences and melting curve analysis was performed. When analyzing the melting curve, the ratio of the peak height of the target and reference chromosome was calculated and determined as aneuploidy if the ratio of peak height was abnormal. All the results from the PNA probe-based real-time PCR and melting curve analyses were compared to those from conventional karyotyping. Forty-two cases with common aneuploidies (24 of trisomy 21, 12 of trisomy 18, and 6 of trisomy 13) and 131 cases with normal karyotype were analyzed. When comparing the karyotyping results, the sensitivity and specificity of the PNA probe-based real-time PCR assay were both 100%. The level of agreement was almost perfect (k = 1.00). PNA real-time PCR assay is a rapid and easy method for detecting common aneuploidies.


Author(s):  
Ika Yasma Yanti ◽  
Dalima Ari Wahono Astrawinata

Toxigenic Clostridium difficile infection, causing a Pseudo Membrane Colitis (PMC) and Clostridium Difficile Associated Diarrhea(CDAD) has increased sharply. The largest risk factor is the use of antibiotics. The purpose of this study was to know how to determinethe prevalence and characteristics of subjects with Toxigenic Clostridium difficile and to assess the ability of the toxin rapid test comparedto real-time PCR. Ninety adult subjects with antibiotic therapy more than two (2) weeks were enrolled in this study. The results of toxinrapid test and real-time PCR were presented in a 2x2 table, statistical test used was Chi square. The prevalence of Toxigenic Clostridiumdifficile based on the toxin rapid test and by real-time PCR was 27.3% and 37.5%, respectively. There were significant differences betweenstool consistency and number of antibiotics used with the detection of Toxigenic Clostridium difficile. There was a relationship betweenthe duration of antibiotic therapy with the detection of Toxigenic Clostridium difficile using real-time PCR (p=0.010, RR=2.116). Thesensitivity, specificity, PPV, NPV, PLR and NLR rapid test against real-time PCR were 69.7%; 98.2%; 95.8%; 84.4%; 39.2 and 0.31,respectively. This study concluded that the prevalence of Clostridium difficile in RSCM was higher compared to that in Malaysia, Thailandand India; the subjects with antibiotic therapy for more than four (4) weeks had a double risk to have Toxigenic Clostridium difficilethan subjects with antibiotic therapy for less than that time (4 weeks). Thus, in this study, toxin rapid test could be used as a tool todetect Toxigenic Clostridium difficile.


2010 ◽  
Vol 134 (3) ◽  
pp. 444-448 ◽  
Author(s):  
Zhengming Gu ◽  
Jianmin Pan ◽  
Matthew J. Bankowski ◽  
Randall T. Hayden

Abstract Context.—BK virus infections among immunocompromised patients are associated with disease of the kidney or urinary bladder. High viral loads, determined by quantitative polymerase chain reaction (PCR), have been correlated with clinical disease. Objective.—To develop and evaluate a novel method for real-time PCR detection and quantification of BK virus using labeled primers. Design.—Patient specimens (n = 54) included 17 plasma, 12 whole blood, and 25 urine samples. DNA was extracted using the MagNA Pure LC Total Nucleic Acid Isolation Kit (Roche Applied Science, Indianapolis, Indiana); sample eluate was PCR-amplified using the labeled primer PCR method. Results were compared with those of a user-developed quantitative real-time PCR method (fluorescence resonance energy transfer probe hybridization). Results.—Labeled primer PCR detected less than 10 copies per reaction and showed quantitative linearity from 101 to 107 copies per reaction. Analytical specificity of labeled primer PCR was 100%. With clinical samples, labeled primer PCR demonstrated a trend toward improved sensitivity compared with the reference method. Quantitative assay comparison showed an R2 value of 0.96 between the 2 assays. Conclusions.—Real-time PCR using labeled primers is highly sensitive and specific for the quantitative detection of BK virus from a variety of clinical specimens. These data demonstrate the applicability of labeled primer PCR for quantitative viral detection and offer a simplified method that removes the need for separate oligonucleotide probes.


2008 ◽  
Vol 98 (5) ◽  
pp. 592-599 ◽  
Author(s):  
Satyanarayana Tatineni ◽  
Uma Shankar Sagaram ◽  
Siddarame Gowda ◽  
Cecile J. Robertson ◽  
William O. Dawson ◽  
...  

Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide, and is caused by a phloem-limited fastidious prokaryotic α-proteobacterium that is yet to be cultured. In this study, a combination of traditional polymerase chain reaction (PCR) and real-time PCR targeting the putative DNA polymerase and 16S rDNA sequence of ‘Candidatus Liberibacter asiaticus,’ respectively, were used to examine the distribution and movement of the HLB pathogen in the infected citrus tree. We found that ‘Ca. Liberibacter asiaticus’ was distributed in bark tissue, leaf midrib, roots, and different floral and fruit parts, but not in endosperm and embryo, of infected citrus trees. Quantification analysis of the HLB bacterium indicated that it was distributed unevenly in planta and ranged from 14 to 137,031 cells/μg of total DNA in different tissues. A relatively high concentration of ‘Ca. Liberibacter asiaticus’ was observed in fruit peduncles. Our data from greenhouse-infected plants also indicated that ‘Ca. Liberibacter asiaticus’ was transmitted systemically from infection site to different parts of the plant. Understanding the distribution and movement of the HLB bacterium inside an individual citrus tree is critical for discerning its virulence mechanism and to develop management strategies for HLB.


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