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1.
Med. infant ; 30(2): 191-197, Junio 2023. ilus
Article in Spanish | LILACS, UNISALUD, BINACIS | ID: biblio-1443762

ABSTRACT

Las enfermedades autoinflamatorias (AIDs) son un grupo heterogéneo de desórdenes monogénicos o poligénicos, con características de disregulación inmune innata y/o adaptativa, cuyo mecanismo central es la autoinflamación pero también pueden presentarse con autoinmunidad e inmunodeficiencia. En estos últimos años el desarrollo de las tecnologías de secuenciación masiva han provocado una explosión en el descubrimiento de nuevos genes responsables de AIDs monogénicas. Esto remarca la importancia de implementar este tipo de estudios para llegar a un diagnóstico definitivo sobre todo en este grupo de patologías genéticamente muy diversas donde los fenotipos clínicos se solapan. Sin embargo, dada la presencia de variantes de significación incierta (VUS), los resultados pueden no ser concluyentes planteándose la necesidad de desarrollar pruebas funcionales para determinar la patogenicidad de dichas variantes genéticas. En nuestro grupo de trabajo estamos aplicando la PCR digital en gotas (ddPCR), una técnica cuantitativa de 3era generación altamente sensible, especifica y reproducible que no necesita de curvas de calibración, para desarrollar pruebas funcionales que permitan no sólo reclasificar variantes VUS para lograr diagnósticos definitivos sino también estudiar los mecanismos responsables de las principales AIDs que permitan una estratificación de las terapéuticas especificas a aplicar y de esta manera poder contribuir al diagnóstico, tratamiento y seguimiento de nuestros pacientes en forma personalizada. (AU)


Autoinflammatory diseases (AIDs) are a heterogeneous group of monogenic or polygenic disorders, with characteristics of inborn and/or adaptive immune dysregulation, whose central mechanism is autoinflammation but may also present with autoimmunity and immunodeficiency. In recent years the development of massive sequencing technologies has led to an exponential increase in the discovery of new genes responsible for monogenic AIDs. This emphasizes the importance of the implementation of this type of studies to make a definitive diagnosis, especially in this group of genetically very diverse diseases with overlapping clinical phenotypes. However, given the presence of variants of uncertain significance (VUS), the results may not be conclusive, raising the need to develop functional tests to determine the pathogenicity of these genetic variants. In our working group we are applying droplet digital PCR (ddPCR), a highly sensitive, specific and reproducible third generation quantitative technique that does not require calibration curves, to develop functional tests that allow not only to reclassify VUS variants to achieve definitive diagnoses but also to study the mechanisms responsible for the main AIDs that allow for the stratification of specific treatments to be used and thereby contribute to the individualized diagnosis, treatment, and follow-up of our patients (AU)


Subject(s)
Humans , Male , Female , Child , Adolescent , Autoimmune Diseases/diagnosis , Therapeutics/instrumentation , Polymerase Chain Reaction/methods , Hereditary Autoinflammatory Diseases/diagnosis , Hereditary Autoinflammatory Diseases/genetics , High-Throughput Nucleotide Sequencing , Laboratories, Hospital
2.
Chinese Journal of Biochemistry and Molecular Biology ; (12): 1356-1364, 2023.
Article in Chinese | WPRIM | ID: wpr-1015650

ABSTRACT

We aim to establish a chip-based digital PCR (dPCR) method for detecting copy number variation of the LAPTM4B gene in non-small cell lung cancer (NSCLC), and preliminarily evaluate its basic performance and clinical feasibility. The LAPTM4B gene primers and specific probes were designed to establish a dPCR reaction system. The detection limit, precision, and linearity of the method were verified according to the prepared target DNA samples of different concentrations. The reaction system of dPCR for LAPTM4B gene copy number detection was established and optimized for the first time. The results showed that 12. 5% of LAPTM4B gene copy number deletion could be detected at the lowest level. The coefficient of variation of inter-batch precision was less than 10%, and the linearity of deletion ratio was good in the range of 12. 5%-100% (R

3.
Chinese Journal of Biologicals ; (12): 429-2023.
Article in Chinese | WPRIM | ID: wpr-976173

ABSTRACT

@#ObjectiveTo develop a national standard for genomic titer determination of recombinant type 5 adeno-associated virus(rAAV5).MethodsThe rAAV5-GFP stock solution prepared by the three-plasmid system was identified and verified for the appearance,pH,sterility,genomic titer,purity and infection titer according to the relevant requirements of Chinese Pharmacopoeia(Volume Ⅲ,2020 edition),which was diluted and subpackaged to prepare candidate standards according to the results;The stability of candidate standards was investigated by thermal acceleration test;Three laboratories were organized to collaboratively calibrate the candidate standards using droplet digital PCR(ddPCR).ResultsAll the detection indexes of the candidate standard and the stock solution met the relevant requirements;The genomic titer showed no significant decrease at 25,4,-20,-40,-80 ℃ for 1,3,4,6 months;Through collaborative calibration by three laboratories,the candidate standard was assigned a value of 2. 56 × 10(12)copies/mL,and the 95% confidence interval was 2. 48 ×10(12)copies/mL,and the 95% confidence interval was 2. 48 ×10(12)copies/mL ~ 2. 64 × 10(12)copies/mL ~ 2. 64 × 10(12)copies/mL.ConclusionThe developed national standard for the determination of rAAV5 genomic titer had good stability and might be used for the quality evaluation of rAAV5 related products.

4.
Chinese Journal of Biologicals ; (12): 826-832+838, 2023.
Article in Chinese | WPRIM | ID: wpr-996492

ABSTRACT

@#Objective To develop a duplex digital PCR(dPCR) for evaluation of the stability of luciferase(Luc) gene in Luc2P reporter cell lines(CHO-K1,Hacat,HEK293 and UT7).Methods Genomic DNAs of Luc2P reporter cell lines were extracted,a duplex dPCR was developed to determine the copies of reference gene RPP30 and the target gene Luc,and the relative copy number of Luc(copies Luc/copy RPP30) was employed as the indicator for the stability evaluation of Luc gene;The developed method was verified for the specificity,precision,linearity,accuracy and durability,and analyzed for the applicability,according to the related requirements in Chinese Pharmacopoeia(Volume Ⅲ,2020 edition).Results All the original cells without reporter gene transfection were negative,while all the four reporter cell lines were positive,and the negative and positive regions in dPCR results were clearly distinguished;The relative standard deviation(RSD) of the eight repeated detections of the same genomic DNA sample and the six independent extractions of genomic DNA sample of the same cell were all less than 10%,and the linear fitting R~2 values were more than 0.99 for both Luc and RPP30.The spike recoveries of five groups of samples detected by the developed method were between 50% and 100%,and the results of chip-type dPCR and droplet-type dPCR were consistent.This method distinguished the relative copy number of Luc in different cell clones,and the results of detecting the relative copy number of Luc in three passages(P8,P12 and P31) were highly consistent.Conclusion The developed duplex dPCR method has good specificity,precision,linearity,accuracy,durability and applicability,and might be used to evaluate the stability of Luc gene in Luc2P reporter cell lines.

5.
Journal of Experimental Hematology ; (6): 653-658, 2022.
Article in Chinese | WPRIM | ID: wpr-939672

ABSTRACT

OBJECTIVE@#To establish the droplet digital PCR (ddPCR) assay for the detection of NPM1 type A mutation in patients with acute myeloid leukemia (AML), and to evaluate its specificity, sensitivity and its value in clinical application.@*METHODS@#NPM1 mutant and wildtype plasmids were used to verify the performance of ddPCR. Both ddPCR and Sanger sequencing were used to detect the bone marrow samples of 87 AML patients, which were confirmed by next generation sequencing (NGS). Moreover, NPM1 mutation burden was dynamically monitored in five patients by ddPCR.@*RESULTS@#The limit of blank (LOB) of ddPCR established for NPM1 mutation detection was 1.1 copies/μl, and the limit of detection (LOD) was 2.43 copies/μl, which had good linearity. Among the 87 newly diagnosed AML patients, ddPCR identified seventeen cases positive for NPM1 mutation (19.5%), which was consistent with Sanger sequencing. NGS confirmed 12 positive cases, including 8 of type A mutations, 2 of type D mutations, and 2 of rare type mutations. The results of dynamic monitoring of NPM1 mutation burden in 5 patients showed that the NPM1 mutation burden decreased obviously even close to 0, when patients achieve complete remission after chemotherapy. However, the mutation burden was increased again at the time of relapse.@*CONCLUSION@#In this study, we established a ddPCR method for detection of NPM1 mutation with good sensitivity and repeatability, which can be used for screening NPM1 mutation in newly diagnosed AML patients and for minimal residual disease monitoring after remission in positive AML patients to guide treatment.


Subject(s)
Humans , Leukemia, Myeloid, Acute/therapy , Mutation , Nuclear Proteins/genetics , Nucleophosmin , Polymerase Chain Reaction , Prognosis
6.
Chinese Journal of Laboratory Medicine ; (12): 948-955, 2021.
Article in Chinese | WPRIM | ID: wpr-912502

ABSTRACT

Objective:To verify the performance of the next-generation sequencing (NGS) platform and evaluate the application of NGS, droplet digital PCR (ddPCR) and super amplification refractory mutation system (super-ARMS) in the detection of circulating free DNA (cfDNA) mutations in patients with non-small-cell lung cancer (NSCLC).Methods:A total of 75 patients with NSCLC in the respiratory department of Zhongshan Hospital Affiliated to Fudan University were enrolled. The standards, cfDNA from 25 patients with newly diagnosed and untreated NSCLC, and self-made mixed samples mixed with hemoglobin (1 000 mg /dl), bilirubin (500 mg/l), fat emulsion (2%), enterococcus gDNA and Escherichia coli gDNA were used to verify the blank limit, analytical sensitivity, precision, accuracy and specificity of NGS platform. The cfDNA mutations of 75 NSCLC patients were detected by ddPCR and NGS, and the mutation positive rates of the two platforms were compared. The linear relationship between the two platforms was compared by Pearson correlation test. 12 patients were selected by simple random sampling for the detection of plasma super-ARMS platform. The performance of three platforms in the detection of plasma cfDNA mutation in patients with NSCLC was compared.Results:The blank limit of NGS platform was set to 0.00%, the analytical sensitivity was 0.2%, the intra-assay precision and inter-assay precision were 100%. The test results were not affected by endogenous hemoglobin, bilirubin or fat emulsion in plasma or exogenous DNA interference, and the analysis specificity was good. The mutation positive rates of plasma cfDNA in 75 NSCLC patients detected by ddPCR and NGS were 61.33% and 60.00%, respectively. The complete coincidence rate was 89.33%, which suggests there was a positive correlation between the mutation abundance of NGS and ddPCR ( r=0.984, P=0.001). Among the plasma of 12 NSCLC patients, the results of NGS, ddPCR and super-ARMS were completely consistent in 7 cases, including 2 wild-types and 5 mutants. Conclusion:The NGS platform was verified to be useful for cfDNA mutation detection in patients with NSCLC. The ddPCR, NGS and super-ARMS have their own advantages in detecting cfDNA mutations in patients with NSCLC.

7.
Chinese Journal of Biochemistry and Molecular Biology ; (12): 890-899, 2021.
Article in Chinese | WPRIM | ID: wpr-1015906

ABSTRACT

Using fluorescence PCR (FPCR) technology to amplify DNA is an important part of modern biological research. The paper traced the invention of FPCR, through its main development, respective principles, design techniques, through to practical applications, etc. The two generations of phased methods of real-time quantitative PCR (QPCR) and digital PCR (DPCR) were mainly reviewed. QPCR that contained means of dyes, hydrolysis probe and its derivatives, hybridization probe containing molecular beacon and Yin-Yang probes, etc, dye melting curve and probe melting curve was summarized. DPCR involving chip digital PCR(cdPCR) and droplet digital PCR (ddPCR) was also included. Furthermore, the main application areas and limitation of FPCR, their characteristics of different types and future development direction were described.

8.
Chinese Journal of Blood Transfusion ; (12): 835-839, 2021.
Article in Chinese | WPRIM | ID: wpr-1004423

ABSTRACT

【Objective】 To establish an efficient digital PCR method for Babesia detection, so as to provide data reference for the follow-up studies and the evaluation of blood supply safety in China. 【Methods】 18S rRNA conservative gene sequence of Babesia spp. was downloaded from Genbank, and primers were designed according to the common part of the sequence to establish a highly sensitive and absolutely quantitative digital PCR detection method for Babesia detection. A total of 1000 red blood cell samples collected from voluntary blood donors in Mudanjiang City from July 19, 2016 to August 24, 2016 were detected using this new digital PCR method. 【Results】 The established digital PCR method for Babesia detection showed a good repeatability and could steadily detect the mono-copied nuclear acid. The positive rate was 0.2%(2/1 000)by this method. The two blood donors were further confirmed positive by Indirect Immunofluorescence Assay (IFA), and preliminarily judged as asymptomatic infection. 【Discussion】 The digital PCR method for Babesia detection established in this study has high sensitivity and stability, and the its application on blood screening is conductive to reduce the threats of asymptomatic infection to blood safety

9.
Journal of Clinical Hepatology ; (12): 1806-1810., 2021.
Article in Chinese | WPRIM | ID: wpr-886335

ABSTRACT

ObjectiveTo establish a droplet digital PCR (ddPCR) method for detecting hepatitis B virus (HBV) covalently closed circular DNA (cccDNA). MethodsHBV cccDNA standard substance was constructed, and HBV cccDNA primers and probes were designed based on the structural differences between HBV cccDNA and relaxed circular DNA (rcDNA). HBV plasmid was amplified to obtain HBV cccDNA standard substance, and a ddPCR detection method was established with the standard substance after gradient dilution as the template for HBV cccDNA detection; the limit of detection and repeatability of this method were analyzed. Liver tissue samples were collected from 20 patients who attended Beijing YouAn Hospital, Capital Medical University, from June 2017 to October 2020, all of whom were diagnosed with HBV infection, and DNA of the samples was extracted and digested with plasmid-safe ATP-dependent DNA enzyme to obtain HBV cccDNA template; the ddPCR detection method was evaluated in clinical samples and was compared with the quantitative real-time PCR (qPCR) detection method. The chi-square test was used for comparison of categorical data between the two groups. ResultsThe HBV cccDNA detection method based on ddPCR was established, which accurately detected HBV cccDNA in standard substance after gradient dilution, with a limit of detection of 1 copy/μl, and the coefficients of variation of 1×103, 1×102, and 1×101 copies/μl standard substances were 441%, 3.98%, and 5.09%, respectively. HBV cccDNA was detected in the samples of 20 patients with HBV infection; the ddPCR detection method detected HBV cccDNA in 17 patients, with a positive rate of 85%, while the qPCR detection method detected HBV cccDNA in 11 patients, with a positive rate of 55%, and there was a significant difference between the two methods (χ2=4.286, P=0038). ConclusionThe established ddPCR method for detecting HBV cccDNA has a low limit of detection and good repeatability, which provides an effective tool for further clinical detection.

10.
Annals of Laboratory Medicine ; : 72-75, 2020.
Article in English | WPRIM | ID: wpr-762451

ABSTRACT

Accurate detection of BCR-ABL fusion transcripts at and below molecular response (MR) 4 (0.01% International Scale [IS]) is required for disease monitoring in patients with chronic myeloid leukemia (CML). We evaluated the analytical performance of the QXDx BCR-ABL %IS (Bio-Rad, Hercules, CA, USA) droplet digital PCR (ddPCR) assay, which is the first commercially available ddPCR-based in vitro diagnostics product. In precision analysis, the %CV was 9.3% and 3.0%, with mean values of 0.031% IS and 9.4% IS, respectively. The assay was linear in the first order, ranging from 0.032% IS to 20% IS. The manufacturer-claimed limit of blank, limit of detection, and limit of quantification were verified successfully. There was a very strong correlation between the results of the QXDx BCR-ABL %IS ddPCR assay and the ipsogen BCR-ABL1 Mbcr IS-MMR (Qiagen, Hilden, Germany) real-time quantitative PCR assay (r=0.996). In conclusion, the QXDx BCR-ABL %IS ddPCR assay can provide reliable results for CML patients.


Subject(s)
Humans , In Vitro Techniques , Leukemia, Myelogenous, Chronic, BCR-ABL Positive , Limit of Detection , Polymerase Chain Reaction
11.
Journal of Zhejiang University. Medical sciences ; (6): 586-590, 2020.
Article in Chinese | WPRIM | ID: wpr-879916

ABSTRACT

OBJECTIVE@#To perform gene mutation analysis in a patient with atypical clinical manifestations of tuberous sclerosis (TSC) for definite diagnosis.@*METHODS@#Peripheral blood DNA was obtained from a patient with clinically suspected TSC and her parents, and all exons and their flanking sequences of @*RESULTS@#A heterozygous nonsense mutation c.1096G>T (p.E366*) was identified in the exon 11 of the @*CONCLUSIONS@#The somatic mosaic mutation c.1096G>T (p.e366*) may be responsible for the phenotype of TSC in this patient. And the drop digital PCR is expected to be a diagnostic method for somatic cells mosaicism.


Subject(s)
Female , Humans , Male , Mosaicism , Mutation , Tuberous Sclerosis/genetics , Tuberous Sclerosis Complex 2 Protein/genetics , Exome Sequencing
12.
Chinese Journal of Biotechnology ; (12): 2193-2205, 2020.
Article in Chinese | WPRIM | ID: wpr-878478

ABSTRACT

Endoglucanase (EG) is an important component of cellulases and play an important role in cellulose degradation. However, its application is limited due to the low yield of endoglucanase from natural microorganisms. Efficient heterologous expression of endoglucanase is an effective way to solve this problem. To obtain the engineered Saccharomyces cerevisiae for high-yield endoglucanase, endoglucanase gene was cloned from Clostridium cellulovorans, with a total length of 1 996 bp, encoding 440 amino acids, and the complete expression cassette (PαEGC) was constructed with the PGK promoter sequence from Saccharomyces cerevisiae, α-signal peptide sequence from pPIC9K plasmid and CYC1 terminator sequence from pSH65 plasmid by gene splicing by overlap extension PCR (SOE PCR), and the expression vector of endoglucanase in Saccharomyces cerevisiae was constructed by rDNA integration. The relationship between copy number and protein expression was explored. Random multicopy expression of endoglucanase was performed in Saccharomyces cerevisiae. The copy number of endoglucanase was identified by Droplet Digital PCR and explore the relationship between copy number and protein expression.The engineered Saccharomyces cerevisiae of endoglucanase with copy numbers of 1, 3, 4, 7, 9, 11, 15, 16, 19, 21, 22 and 23 were obtained by rDNA integration, respectively. The results showed that when the copy number was 15, the enzyme activity was the highest, namely 351 U/mL. The engineered strain of Saccharomyces cerevisiae for endoglucanase was successfully constructed, which can provide reference for the heterologous expression of other industrial enzymes.


Subject(s)
Cellulase/genetics , Genetic Engineering , Industrial Microbiology , Plasmids/genetics , Saccharomyces cerevisiae/genetics
13.
Journal of Southern Medical University ; (12): 601-605, 2020.
Article in Chinese | WPRIM | ID: wpr-828110

ABSTRACT

Since the outbreak of COVID-19 pandemic, the detection capability has been improving and the detection techniques have been evolving with innovations. qRT- PCR and mNGS, which represent the current mainstay diagnostic technologies, play key roles in disease diagnosis and monitoring of virus variation. The detection technologies based on serum and plasma IgM and IgG antibodies are important for auxiliary diagnosis. RT-LAMP is highly specific for a diagnostic purpose. Digital PCR could quantitatively detect nucleic acid and SHERLOCK has a higher sensitivity. These techniques all have great potential for future development and application for pathogen detection. In this review the authors summarize the basic rationales, technical characteristics and the current application of the SARS-CoV-2 detection techniques.


Subject(s)
Humans , Antibodies, Viral , Betacoronavirus , Clinical Laboratory Techniques , Coronavirus Infections , Diagnosis , Immunoglobulin G , Immunoglobulin M , Pandemics , Pneumonia, Viral , Diagnosis
14.
Genomics & Informatics ; : 42-2019.
Article in English | WPRIM | ID: wpr-785799

ABSTRACT

Robust identification of genetic alterations is important for the diagnosis and subsequent treatment of tumors. Screening for genetic alterations using tumor tissue samples may lead to biased interpretations because of the heterogeneous nature of the tumor mass. Liquid biopsy has been suggested as an attractive tool for the non-invasive follow-up of cancer treatment outcomes. In this study, we aimed to verify whether the mutations identified in primary tumor tissue samples could be consistently detected in plasma cell–free DNA (cfDNA) by digital polymerase chain reaction (dPCR). We first examined the genetic alteration profiles of three colorectal cancer (CRC) tissue samples by targeted next-generation sequencing (NGS) and identified 11 non-silent amino acid changes across six cancer-related genes (APC, KRAS, TP53, TERT, ARIDIA, and BRCA1). All three samples had KRAS mutations (G12V, G12C, and G13D), which were well-known driver events. Therefore, we examined the KRAS mutations by dPCR. When we examined the three KRAS mutations by dPCR using tumor tissue samples, all of them were consistently detected and the variant allele frequencies (VAFs) of the mutations were almost identical between targeted NGS and dPCR. When we examined the KRAS mutations using the plasma cfDNA of the three CRC patients by dPCR, all three mutations were consistently identified. However, the VAFs were lower (range, 0.166% to 2.638%) than those obtained using the CRC tissue samples. In conclusion, we confirmed that the KRAS mutations identified from CRC tumor tissue samples were consistently detected in the plasma cfDNA of the three CRC patients by dPCR.


Subject(s)
Humans , Bias , Biopsy , Colorectal Neoplasms , Diagnosis , DNA , Follow-Up Studies , Gene Frequency , Mass Screening , Plasma , Polymerase Chain Reaction
15.
Chinese Journal of Experimental and Clinical Virology ; (6): 664-668, 2018.
Article in Chinese | WPRIM | ID: wpr-806661

ABSTRACT

In recent years, digital PCR (dPCR), as a novel nucleic acid amplification detection technique, contrasts real-time fluorescent quantitative PCR (qPCR) without the need to establish a standard curve, "single molecule template amplification" absolute quantification, insensitive to inhibitors that affect PCR efficiency, and excellent sensitivity, specificity, extremely strong repeatability and the development of the existing commercial platform technology that has great application advantages in virology and nucleic acid quantification. In this review, we address the application advantages of digital PCR in virus detection and describe its future development.

16.
Biomedical and Environmental Sciences ; (12): 713-720, 2018.
Article in English | WPRIM | ID: wpr-690599

ABSTRACT

<p><b>OBJECTIVE</b>Shellfish are recognized as important vehicles of norovirus-associated gastroenteritis. The present study aimed to monitor norovirus contamination in oysters along the farm-to-fork continuum in Guangxi, a major oyster production area in Southwestern China.</p><p><b>METHODS</b>Oyster samples were collected monthly from farms, markets, and restaurants, from January to December 2016. Norovirus was detected and quantified by one-step reverse transcription-droplet digital polymerase chain reaction (RT-ddPCR).</p><p><b>RESULTS</b>A total of 480 oyster samples were collected and tested for norovirus genogroups I and II. Norovirus was detected in 20.7% of samples, with genogroup II predominating. No significant difference was observed in norovirus prevalence among different sampling sites. The norovirus levels varied widely, with a geometric mean of 19,300 copies/g in digestive glands. Both norovirus prevalence and viral loads showed obvious seasonality, with a strong winter bias.</p><p><b>CONCLUSION</b>This study provides a systematic analysis of norovirus contamination 'from the farm to the fork' in Guangxi. RT-ddPCR can be a useful tool for detection and quantification of low amounts of norovirus in the presence of inhibitors found particularly in foodstuffs. This approach will contribute to the development of strategies for controlling and reducing the risk of human illness resulting from shellfish consumption.</p>

17.
Chinese Journal of Biotechnology ; (12): 407-420, 2018.
Article in Chinese | WPRIM | ID: wpr-690161

ABSTRACT

This study aims to develop a new method for the detection of KRAS mutations related to colorectal cancer in cfDNA, and to evaluate the sensitivity and accuracy of the detection. We designed a method of cfDNA based KRAS detection by droplets digital PCR (ddPCR). The theoretical performance of the method is evaluated by reference standard and compared to the ARMS PCR method. Two methods, ddPCR and qPCR, were successfully established to detect KRAS wild type and 7 mutants. Both methods were validated using plasmid standards and actual samples. The results were evaluated by false positive rate, linearity, and limit of detection. Finally, 52 plasma cfDNA samples from patients and 20 samples from healthy people were tested, the clinical sensitivity is 97.64%, clinical specificity is 81.43%. ddPCR method shows higher performance than qPCR. The LOD of ddPCR method reached single digits of cfDNA copies, it can detect as low as 0.01% to 0.04% mutation abundance.

18.
Chinese Journal of Clinical Oncology ; (24): 146-149, 2017.
Article in Chinese | WPRIM | ID: wpr-507315

ABSTRACT

In the context of precision medicine, although individual treatment of breast cancer under the guidance of molecular classi-fication has become the norm, a precision treatment program with increased efficiency and quality is still required. Compared with the traditional real-time fluorescent quantitative polymerase chain reaction (PCR), the droplet digital PCR (ddPCR) has obvious advantages in the detection of rare mutations and copy number variations, as well as the integration with the second-generation-sequencing tech-nology. This paper reviews the application of a ddPCR platform in different breast cancer subtypes and explores new horizons of breast cancer research through the ddPCR technology.

19.
Genomics & Informatics ; : 2-10, 2017.
Article in English | WPRIM | ID: wpr-69984

ABSTRACT

Early detection and proper management of kidney rejection are crucial for the long-term health of a transplant recipient. Recipients are normally monitored by serum creatinine measurement and sometimes with graft biopsies. Donor-derived cell-free deoxyribonucleic acid (cfDNA) in the recipient's plasma and/or urine may be a better indicator of acute rejection. We evaluated digital PCR (dPCR) as a system for monitoring graft status using single nucleotide polymorphism (SNP)-based detection of donor DNA in plasma or urine. We compared the detection abilities of the QX200, RainDrop, and QuantStudio 3D dPCR systems. The QX200 was the most accurate and sensitive. Plasma and/or urine samples were isolated from 34 kidney recipients at multiple time points after transplantation, and analyzed by dPCR using the QX200. We found that donor DNA was almost undetectable in plasma DNA samples, whereas a high percentage of donor DNA was measured in urine DNA samples, indicating that urine is a good source of cfDNA for patient monitoring. We found that at least 24% of the highly polymorphic SNPs used to identify individuals could also identify donor cfDNA in transplant patient samples. Our results further showed that autosomal, sex-specific, and mitochondrial SNPs were suitable markers for identifying donor cfDNA. Finally, we found that donor-derived cfDNA measurement by dPCR was not sufficient to predict a patient's clinical condition. Our results indicate that donor-derived cfDNA is not an accurate predictor of kidney status in kidney transplant patients.


Subject(s)
Humans , Biopsy , Creatinine , DNA , Kidney Transplantation , Kidney , Monitoring, Physiologic , Plasma , Polymerase Chain Reaction , Polymorphism, Single Nucleotide , Tissue Donors , Transplant Recipients , Transplants
20.
Chinese Journal of Biotechnology ; (12): 170-177, 2017.
Article in Chinese | WPRIM | ID: wpr-310601

ABSTRACT

Digital PCR is an emerging analysis technology for absolute quantification after realtime-PCR. Through digital PCR, single DNA molecules are distributed into isolated reactions, and the product with fluorescence signal can be detected and analyzed after amplification. With the advantages of higher sensitivity and accuracy, digital PCR, independent of a standard curve, is developing rapidly and applied widely to the next generation sequencing and detection fields, such as gene mutation, copy number variation, microorganism, and genetically modified food. In this article, we reviewed the quantitative method and research progress of digital PCR technology in the main application fields.

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