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1.
Sci Rep ; 14(1): 12389, 2024 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-38811625

RESUMO

Extracellular vesicles have emerged as important mediators of cell-to-cell communication in the pathophysiology of fibrotic diseases. One such disease is Peyronie's disease (PD), a fibrotic disorder of the penis caused by uncontrolled transformation of resident fibroblasts to alpha-smooth muscle actin positive myofibroblasts. These cells produce large amounts of extracellular matrix, leading to formation of a plaque in the penile tunica albuginea (TA), causing pain, penile curvature, and erectile dysfunction. We have used primary fibroblasts derived from the TA of PD patients to explore the role of transforming growth factor beta 1 (TGF-ß1), a key signalling factor in this process. TGF-ß1 treatment elicited a range of responses from the myofibroblasts: (i) they secreted extracellular vesicles (EVs) that were more numerous and differed in size and shape from those secreted by fibroblasts, (ii) these EVs prevented TGF-ß1-induced transformation of fibroblasts in a manner that was dependent on vesicle uptake and (iii) they prevented phosphorylation of Erk1/2, a critical component in modulating fibrogenic phenotypic responses, but did not affect TGF-ß1-induced Smad-signalling. We posit that this effect could be linked to enrichment of TSG-6 in myofibroblast-derived EVs. The ability of myofibroblast-derived vesicles to prevent further myofibroblast transformation may establish them as part of an anti-fibrotic negative feedback loop, with potential to be exploited for future therapeutic approaches.


Assuntos
Vesículas Extracelulares , Fibroblastos , Miofibroblastos , Fator de Crescimento Transformador beta1 , Vesículas Extracelulares/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Humanos , Miofibroblastos/metabolismo , Fosforilação , Masculino , Fibroblastos/metabolismo , Moléculas de Adesão Celular/metabolismo , Sistema de Sinalização das MAP Quinases , Induração Peniana/metabolismo , Induração Peniana/patologia , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Células Cultivadas , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Transdução de Sinais
2.
Int J Mol Sci ; 25(5)2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38474020

RESUMO

Versatility, sensitivity, and accuracy have made the real-time polymerase chain reaction (qPCR) a crucial tool for research, as well as diagnostic applications. However, for point-of-care (PoC) use, traditional qPCR faces two main challenges: long run times mean results are not available for half an hour or more, and the requisite high-temperature denaturation requires more robust and power-demanding instrumentation. This study addresses both issues and revises primer and probe designs, modified buffers, and low ∆T protocols which, together, speed up qPCR on conventional qPCR instruments and will allow for the development of robust, point-of-care devices. Our approach, called "FlashPCR", uses a protocol involving a 15-second denaturation at 79 °C, followed by repeated cycling for 1 s at 79 °C and 71 °C, together with high Tm primers and specific but simple buffers. It also allows for efficient reverse transcription as part of a one-step RT-qPCR protocol, making it universally applicable for both rapid research and diagnostic applications.


Assuntos
Transcrição Reversa , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sensibilidade e Especificidade
3.
J Sex Med ; 21(4): 278-287, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38383071

RESUMO

BACKGROUND: Transformation of resident fibroblasts to profibrotic myofibroblasts in the tunica albuginea is a critical step in the pathophysiology of Peyronie's disease (PD). We have previously shown that myofibroblasts do not revert to the fibroblast phenotype and we suggested that there is a point of no return at 36 hours after induction of the transformation. However, the molecular mechanisms that drive this proposed irreversibility are not known. AIM: Identify molecular pathways that drive the irreversibility of myofibroblast transformation by analyzing the expression of the genes involved in the process in a temporal fashion. METHODS: Human primary fibroblasts obtained from tunica albuginea of patients with Peyronie's disease were transformed to myofibroblasts using transforming growth factor beta 1 (TGF-ß1). The mRNA of the cells was collected at 0, 24, 36, 48, and 72 hours after stimulation with TGF-ß1 and then analyzed using a Nanostring nCounter Fibrosis panel. The gene expression results were analyzed using Reactome pathway analysis database and ANNi, a deep learning-based inference algorithm based on a swarm approach. OUTCOMES: The study outcome was the time course of changes in gene expression during transformation of PD-derived fibroblasts to myofibroblasts. RESULTS: The temporal analysis of the gene expression revealed that the majority of the changes at the gene expression level happened within the first 24 hours and remained so throughout the 72-hour period. At 36 hours, significant changes were observed in genes involved in MAPK-Hedgehog signaling pathways. CLINICAL TRANSLATION: This study highlights the importance of early intervention in clinical management of PD and the future potential of new drugs targeting the point of no return. STRENGTHS AND LIMITATIONS: The use of human primary cells and confirmation of results with further RNA analysis are the strengths of this study. The study was limited to 760 genes rather than the whole transcriptome. CONCLUSION: This study is to our knowledge the first analysis of temporal gene expression associated with the regulation of the transformation of resident fibroblasts to profibrotic myofibroblasts in PD. Further research is warranted to investigate the role of the MAPK-Hedgehog signaling pathways in reversibility of PD.


Assuntos
Induração Peniana , Masculino , Humanos , Induração Peniana/genética , Miofibroblastos/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Proteínas Hedgehog/metabolismo , Pênis , Células Cultivadas , Fibroblastos/metabolismo
4.
Mol Aspects Med ; 96: 101249, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38290180

RESUMO

The quantitative polymerase chain reaction (qPCR) is fundamental to molecular biology. It is not just a laboratory technique, qPCR is a bridge between research and clinical practice. Its theoretical foundations guide the design of experiments, while its practical implications extend to diagnostics, treatment, and research advancements in the life sciences, human and veterinary medicine, agriculture, and forensics. However, the accuracy, reliability and reproducibility of qPCR data face challenges arising from various factors associated with experimental design, execution, data analysis and inadequate reporting details. Addressing these concerns, the Minimum Information for the Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines have emerged as a cohesive framework offering a standardised set of recommendations that describe the essential information required for assessing qPCR experiments. By emphasising the importance of methodological rigour, the MIQE guidelines have made a major contribution to improving the trustworthiness, consistency, and transparency of many published qPCR results. However, major challenges related to awareness, resources, and publication pressures continue to affect their consistent application.


Assuntos
Reprodutibilidade dos Testes , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos
5.
Int J Mol Sci ; 24(18)2023 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-37762471

RESUMO

The escalating impacts of the climate crisis, zoonotic spill-over, and antibiotic resistance have positioned molecular medicine at the forefront of pioneering translational research [...].

6.
Mol Oncol ; 17(5): 713-717, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36916500

RESUMO

Accuracy and transparency of scientific data are becoming more and more relevant with the increasing concern regarding the evaluation of data reproducibility in many research areas. This concern is also true for quantifying coding and noncoding RNAs, with the remarkable increase in publications reporting RNA profiling and sequencing studies. To address the problem, we propose the following recommendations: (a) accurate documentation of experimental procedures in Materials and methods (and not only in the supplementary information, as many journals have a strict mandate for making Materials and methods as visible as possible in the main text); (b) submission of RT-qPCR raw data for all experiments reported; and (c) adoption of a unified, simple format for submitted RT-qPCR raw data. The Real-time PCR Data Essential Spreadsheet Format (RDES) was created for this purpose.


Assuntos
RNA , Humanos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase em Tempo Real/métodos
7.
Int J Mol Sci ; 24(5)2023 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-36902493

RESUMO

Molecular pathology, diagnostics and therapeutics are three closely related topics of critical importance in medical research and clinical practice [...].


Assuntos
Patologia Molecular
8.
Int J Mol Sci ; 23(15)2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35955620

RESUMO

The COVID-19 pandemic resulted in a universal, immediate, and vast demand for comprehensive molecular diagnostic testing, especially real-time quantitative (qPCR)-based methods. This rapidly triggered a global shortage of testing capacity, equipment, and reagents. Even today, supply times for chemicals from date of order to delivery are often much longer than pre-pandemic. Furthermore, many companies have ratcheted up the price for minimum volumes of reaction master mixes essential for qPCR assays, causing additional problems for academic laboratories often operating on a shoestring. We have validated two strategies that stretch reagent supplies and, whilst particularly applicable in case of scarcity, can readily be incorporated into standard qPCR protocols, with appropriate validation. The first strategy demonstrates equivalent performance of a selection of "past expiry date" and newly purchased master mixes. This approach is valid for both standard and fast qPCR protocols. The second validates the use of these master mixes at less than 1x final concentration without loss of qPCR efficiency or sensitivity.


Assuntos
COVID-19 , Pandemias , COVID-19/epidemiologia , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sensibilidade e Especificidade
9.
Int J Mol Sci ; 23(3)2022 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-35163227

RESUMO

Reverse transcription of RNA coupled to amplification of the resulting cDNA by the polymerase chain reaction (RT-PCR) is one of the principal molecular technologies in use today, with applications across all areas of science and medicine. In its real-time, fluorescence-based usage (RT-qPCR), it has long been a core technology driving the accurate, rapid and sensitive laboratory diagnosis of infectious diseases. However, RT-qPCR protocols have changed little over the past 30 years, with the RT step constituting a significant percentage of the time taken to complete a typical RT-qPCR assay. When applied to research investigations, reverse transcription has been evaluated by criteria such as maximum yield, length of transcription, fidelity, and faithful representation of an RNA pool. Crucially, however, these are of less relevance in a diagnostic RT-PCR test, where speed and sensitivity are the prime RT imperatives, with specificity contributed by the PCR component. We propose a paradigm shift that omits the requirement for a separate high-temperature RT step at the beginning of an RT-qPCR assay. This is achieved by means of an innovative protocol that incorporates suitable reagents with a revised primer and amplicon design and we demonstrate a proof of principle that incorporates the RT step as part of the PCR assay setup at room temperature. Use of this modification as part of a diagnostic assay will of course require additional characterisation, validation and optimisation of the PCR step. Combining this revision with our previous development of fast qPCR protocols allows completion of a 40 cycle RT-qPCR run on a suitable commercial instrument in approximately 15 min. Even faster times, in combination with extreme PCR procedures, can be achieved.


Assuntos
Teste de Ácido Nucleico para COVID-19/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , SARS-CoV-2/genética , COVID-19/diagnóstico , Técnicas de Laboratório Clínico , Primers do DNA/química , Primers do DNA/genética , Humanos , Técnicas de Diagnóstico Molecular/métodos , RNA Viral/genética , Transcrição Reversa/fisiologia , Sensibilidade e Especificidade , Temperatura
10.
Methods ; 201: 5-14, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34454016

RESUMO

Coronavirus disease 2019 (COVID-19) is an infectious, acute respiratory disease caused mainly by person-to-person transmission of the coronavirus SARS-CoV-2. Its emergence has caused a world-wide acute health crisis, intensified by the challenge of reliably identifying individuals likely to transmit the disease. Diagnosis is hampered by the many unknowns surrounding this disease, including those relating to infectious viral burden. This uncertainty is exacerbated by disagreement surrounding the clinical relevance of molecular testing using reverse transcription quantitative PCR (RT-qPCR) for the presence of viral RNA, most often based on the reporting of quantification cycles (Cq), which is also termed the cycle threshold (Ct) or crossing point (Cp). Despite it being common knowledge that Cqs are relative values varying according to a wide range of different parameters, there have been efforts to use them as though they were absolute units, with Cqs below an arbitrarily determined value, deemed to signify a positive result and those above, a negative one. Our results investigated the effects of a range of common variables on Cq values. These data include a detailed analysis of the effect of different carrier molecules on RNA extraction. The impact of sample matrix of buccal swabs and saliva on RNA extraction efficiency was demonstrated in RT-qPCR and the impact of potentially inhibiting compounds in urine along with bile salts were investigated in RT-digital PCR (RT-dPCR). The latter studies were performed such that the impact on the RT step could be separated from the PCR step. In this way, the RT was shown to be more susceptible to inhibitors than the PCR. Together, these studies demonstrate that the consequent variability of test results makes subjective Cq cut-off values unsuitable for the identification of infectious individuals. We also discuss the importance of using reliable control materials for accurate quantification and highlight the substantial role played by dPCR as a method for their development.


Assuntos
COVID-19 , SARS-CoV-2 , COVID-19/diagnóstico , Humanos , RNA Viral/análise , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , Transcrição Reversa , SARS-CoV-2/genética , Sensibilidade e Especificidade
11.
Water Res ; 203: 117516, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34412018

RESUMO

Due to the coronavirus disease 2019 (COVID-19) pandemic, wastewater surveillance has become an important tool for monitoring the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) within communities. In particular, reverse transcription-quantitative PCR (RT-qPCR) has been used to generate large datasets aimed at detecting and quantifying SARS-CoV-2 RNA in wastewater. Although RT-qPCR is rapid and sensitive, there is no standard method yet, there are no certified quantification standards, and experiments are conducted using different assays, reagents, instruments, and data analysis protocols. These variations can induce errors in quantitative data reports, thereby potentially misleading interpretations, and conclusions. We review the SARS-CoV-2 wastewater surveillance literature focusing on variability of RT-qPCR data as revealed by inconsistent standard curves and associated parameters. We find that variation in these parameters and deviations from best practices, as described in the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines suggest a frequent lack of reproducibility and reliability in quantitative measurements of SARS-CoV-2 RNA in wastewater.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos Testes , Transcrição Reversa , Águas Residuárias
12.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34445406

RESUMO

The reverse transcription quantitative polymerase chain reaction (RT-qPCR) is an established tool for the diagnosis of RNA pathogens. Its potential for automation has caused it to be used as a presence/absence diagnostic tool even when RNA quantification is not required. This technology has been pushed to the forefront of public awareness by the COVID-19 pandemic, as its global application has enabled rapid and analytically sensitive mass testing, with the first assays targeting three viral genes published within days of the publication of the SARS-CoV-2 genomic sequence. One of those, targeting the RNA-dependent RNA polymerase gene, has been heavily criticised for supposed scientific flaws at the molecular and methodological level, and this criticism has been extrapolated to doubts about the validity of RT-qPCR for COVID-19 testing in general. We have analysed this assay in detail, and our findings reveal some limitations but also highlight the robustness of the RT-qPCR methodology for SARS-CoV-2 detection. Nevertheless, whilst our data show that some errors can be tolerated, it is always prudent to confirm that the primer and probe sequences complement their intended target, since, when errors do occur, they may result in a reduction in the analytical sensitivity. However, in this case, it is unlikely that a mismatch will result in poor specificity or a significant number of false-positive SARS-CoV-2 diagnoses, especially as this is routinely checked by diagnostic laboratories as part of their quality assurance.


Assuntos
Teste para COVID-19/métodos , COVID-19/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , SARS-CoV-2/isolamento & purificação , COVID-19/epidemiologia , COVID-19/virologia , Técnicas de Laboratório Clínico/métodos , Humanos , Pandemias , RNA Viral/genética , RNA Polimerase Dependente de RNA , SARS-CoV-2/genética , Sensibilidade e Especificidade , Temperatura
13.
Int J Mol Sci ; 22(5)2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33671091

RESUMO

Although molecular testing, and RT-qPCR in particular, has been an indispensable component in the scientific armoury targeting SARS-CoV-2, there are numerous falsehoods, misconceptions, assumptions and exaggerated expectations with regards to capability, performance and usefulness of the technology. It is essential that the true strengths and limitations, although publicised for at least twenty years, are restated in the context of the current COVID-19 epidemic. The main objective of this commentary is to address and help stop the unfounded and debilitating speculation surrounding its use.


Assuntos
Teste para COVID-19/métodos , COVID-19/diagnóstico , COVID-19/virologia , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , SARS-CoV-2/isolamento & purificação , Técnicas de Laboratório Clínico/métodos , Humanos , RNA Viral/análise , RNA Viral/genética , SARS-CoV-2/genética , Sensibilidade e Especificidade
14.
Sci Rep ; 10(1): 22214, 2020 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-33335187

RESUMO

Accurate, reliable and rapid detection of SARS-CoV-2 is essential not only for correct diagnosis of individual COVID-19 disease but also for the development of a rational strategy aimed at lifting confinement restrictions and preparing for possible recurrent waves of viral infections. We have used the MIQE guidelines to develop two versions of a unique five plex RT-qPCR test, termed CoV2-ID, that allows the detection of three viral target genes, a human internal control for confirming the presence of human cells in a sample and a control artificial RNA for quality assessment and potential quantification. Viral targets can be detected either individually with separate fluorophores or jointly using the same fluorophore, thus increasing the test's reliability and sensitivity. It is robust, can consistently detect two copies of viral RNA, with a limit of detection of a single copy and can be completed in around 15 min. It was 100% sensitive and 100% specific when tested on 23 RNA samples extracted from COVID-19 positive patients and five COVID-19 negative patients. We also propose using multiple cycle fluorescence detection, rather than real-time PCR to reduce significantly the time taken to complete the assay as well as assuage the misunderstandings underlying the use of quantification cycles (Cq). Finally, we have designed an assay for the detection of the D614G mutation and show that all of the samples isolated in the Chelmsford, Essex area between mid-April and June 2020, have the mutant genotype whereas a sample originating in Australia was infected with the wild type genotype.


Assuntos
COVID-19/diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , SARS-CoV-2/genética , Austrália , COVID-19/virologia , Genes Virais/genética , Humanos , Mutação/genética , RNA Viral/genética , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
16.
J Sex Med ; 17(10): 1848-1864, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32771352

RESUMO

BACKGROUND: Myofibroblast transformation is a key step in the pathogenesis of Peyronie's disease (PD). Phosphodiesterase type 5 inhibitors (PDE5is) and selective estrogen receptor modulators (SERMs) can prevent the formation of fibrosis in in vitro and in vivo models of PD. However, it is unknown whether these drugs can also reverse established fibrosis. AIM: To investigate whether PDE5is and SERMs can reverse transforming growth factor beta 1 (TGF-ß1)-induced myofibroblast transformation and determine the point of no return. METHODS: In-Cell enzyme-linked immunosorbent assay was used to quantify TGF-ß1-induced myofibroblast transformation of human primary fibroblasts isolated from tunica albuginea (TA) of patients undergoing surgery for treatment of PD. Extracellular matrix production and collagen contraction assays were used as secondary assays. Reverse transcription-quantitative polymerase chain reaction and In-Cell enzyme-linked immunosorbent assay were used to measure drug target expression. PDE5i (vardenafil) and SERM (tamoxifen) were applied at various time points after TGF-ß1. OUTCOMES: Reversibility of myofibroblast transformation and drug target expression were investigated in a time-dependent manner in TA-derived fibroblasts. RESULTS: Vardenafil or tamoxifen could not reverse the myofibroblast traits of alpha-smooth muscle actin expression and extracellular matrix production, whereas only tamoxifen affected collagen contraction after 72 hours of TGF-ß1 treatment. Phosphodiesterase 5A and estrogen receptor (ER)-ß were downregulated after 72 hours, and estrogen receptor -α protein could not be quantified. Tamoxifen could prevent myofibroblast transformation until 36 hours after TGF-ß1 treatment, whereas vardenafil could prevent only 24 hours after TGF-ß1 treatment. This was mirrored by downregulation of drug targets on mRNA and protein level. Furthermore, antifibrotic signaling pathways, peroxisome proliferator-activated receptor gamma and betaglycan (TGFB receptor III), were significantly downregulated after 36 hours of TGF-ß1 exposure, as opposed to upregulation of profibrotic thrombospondin-1 at the same time point. CLINICAL TRANSLATION: This study suggests that using PDE5is and SERMs might only help for early-phase PD and further highlights the need to test drugs at the appropriate stage of the disease based on their mechanism of action. STRENGTHS & LIMITATIONS: The study uses primary human TA-derived fibroblasts that enhances translatability of the results. Limitations include that only 1 example of PDE5i- and SERM-type drug was tested. Time course experiments were only performed for marker expression experiments and not for functional assays. CONCLUSION: This is the first study to demonstrate that timing for administration of drugs affecting myofibroblast transformation appears to be vital in in vitro models of PD, where 36 hours of TGF-ß1 treatment can be suggested as a "point of no return" for myofibroblast transformation. Ilg MM, Stafford SJ, Mateus M, et al. Phosphodiesterase Type 5 Inhibitors and Selective Estrogen Receptor Modulators Can Prevent But Not Reverse Myofibroblast Transformation in Peyronie's Disease. J Sex Med 2020;17:1848-1864.


Assuntos
Induração Peniana , Preparações Farmacêuticas , Actinas , Células Cultivadas , Fibroblastos , Humanos , Masculino , Miofibroblastos , Induração Peniana/tratamento farmacológico , Pênis , Inibidores da Fosfodiesterase 5/farmacologia , Inibidores da Fosfodiesterase 5/uso terapêutico , Moduladores Seletivos de Receptor Estrogênico/farmacologia , Moduladores Seletivos de Receptor Estrogênico/uso terapêutico , Fator de Crescimento Transformador beta1
17.
Int J Mol Sci ; 21(8)2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32344568

RESUMO

Testing for the presence of coronavirus is an essential diagnostic tool for monitoring and managing the current COVID-19 pandemic. The only reliable test in current use for testing acute infection targets the genome of SARS-CoV-2, and the most widely used method is quantitative fluorescence-based reverse transcription polymerase chain reaction (RT-qPCR). Despite its ubiquity, there is a significant amount of uncertainty about how this test works, potential throughput and reliability. This has resulted in widespread misrepresentation of the problems faced using this test during the current COVID-19 epidemic. This primer provides simple, straightforward and impartial information about RT-qPCR.


Assuntos
Betacoronavirus/isolamento & purificação , Técnicas de Laboratório Clínico/métodos , Primers do DNA , Reação em Cadeia da Polimerase em Tempo Real/métodos , Betacoronavirus/genética , COVID-19 , Teste para COVID-19 , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Pandemias , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia , RNA Viral/genética , RNA Viral/isolamento & purificação , SARS-CoV-2
18.
Methods Mol Biol ; 2065: 5-22, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31578684

RESUMO

Primers are critical components of any PCR assay, as they are the main determinants of its specificity, sensitivity, and robustness. Despite the publication of numerous guidelines, the actual design of many published assays is often unsound: primers lack the claimed specificity, they may have to compete with secondary structures at their binding sites, primer dimer formation may affect the assay's sensitivity or they may bind only within a narrow temperature range. This chapter provides simple guidance to avoid these most common issues.


Assuntos
Primers do DNA/química , Reação em Cadeia da Polimerase/métodos , Sítios de Ligação/genética , Primers do DNA/genética , Limite de Detecção , Conformação de Ácido Nucleico , Reprodutibilidade dos Testes , Temperatura
19.
Biomol Detect Quantif ; 15: 13-17, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29922589

RESUMO

Human health and safety depend on reliable measurements in medical diagnosis and on tests that support the selection and evaluation of therapeutic intervention and newly discovered molecular biomarkers must pass a rigorous evaluation process if they are to be of benefit to patients. Measurement standardization helps to maximize data quality and confidence and ultimately improves the reproducibility of published research. Failure to consider how a given experiment may be standardized can be costly, both financially as well as in time and failure to perform and report pre-clinical research in an appropriately rigorous manner will hinder the development of diagnostic methods. Hence standardization is a crucial step in maintaining the integrity of scientific studies and is a key feature of robust investigation.

20.
Mycoses ; 61(6): 355-359, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29460450

RESUMO

The newly developed AspID PCR assay for detection of Aspergillus spp. was evaluated with an interlaboratory quality control programme panel and human bronchoalveolar lavage fluid (BALF) samples. With the quality control programme, 8 out of 9 panel members were correctly identified. With the clinical study, 36 BALF samples that had been obtained from 18 patients with invasive pulmonary aspergillosis (IPA) and 18 without IPA were investigated. Sensitivity, specificity, positive and negative likelihood ratio for the AspID assay were 94.1% (95% CI 73.3-99.9), 76.5% (95% CI 50.1-93.2), 4 (95% CI 1.7-9.5) and 0.1 (95% CI 0.01-0.5) respectively.


Assuntos
Aspergillus/isolamento & purificação , Líquido da Lavagem Broncoalveolar/microbiologia , Aspergilose Pulmonar Invasiva/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase Multiplex/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos de Fungos/genética , Antígenos de Fungos/isolamento & purificação , Aspergilose/diagnóstico , Aspergilose/microbiologia , Aspergillus/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Aspergilose Pulmonar Invasiva/microbiologia , Masculino , Mananas/análise , Pessoa de Meia-Idade , Técnicas de Diagnóstico Molecular/normas , Reação em Cadeia da Polimerase Multiplex/normas , Projetos Piloto , Controle de Qualidade , Sensibilidade e Especificidade
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