scholarly journals Rapid, Sensitive, and Specific Severe Acute Respiratory Syndrome Coronavirus 2 Detection: A Multicenter Comparison Between Standard Quantitative Reverse-Transcriptase Polymerase Chain Reaction and CRISPR-Based DETECTR

2020 ◽  
Author(s):  
Eelke Brandsma ◽  
Han J M P Verhagen ◽  
Thijs J W van de Laar ◽  
Eric C J Claas ◽  
Marion Cornelissen ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Severe Acute Respiratory Syndrome ◽  
Reverse Transcriptase ◽  
N Gene ◽  
Analytical Sensitivity ◽  
Chain Reaction ◽  
Qrt Pcr ◽  
Ribonucleoprotein Complexes ◽  
Large Patient ◽  
Polymerase Chain

Abstract Background Recent advances in CRISPR-based diagnostics suggest that DETECTR, a combination of reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) and subsequent Cas12 bystander nuclease activation by amplicon-targeting ribonucleoprotein complexes, could be a faster and cheaper alternative to quantitative reverse-transcription polymerase chain reaction (qRT-PCR) without sacrificing sensitivity and/or specificity. Methods In this study, we compare DETECTR with qRT-PCR to diagnose coronavirus disease 2019 on 378 patient samples. Patient sample dilution assays suggest a higher analytical sensitivity of DETECTR compared with qRT-PCR; however, this was not confirmed in this large patient cohort, where we report 95% reproducibility between the 2 tests. Results These data showed that both techniques are equally sensitive in detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) providing additional value of DETECTR to the currently used qRT-PCR platforms. For DETECTR, different guide ribonucleic acids can be used simultaneously to obviate negative results due to mutations in N-gene. Lateral flow strips, suitable as a point-of-care test, showed a 100% correlation to the high-throughput DETECTR assay. More importantly, DETECTR was 100% specific for SARS-CoV-2 relative to other human coronaviruses. Conclusions Because there is no need for specialized equipment, DETECTR could be rapidly implemented as a complementary technically independent approach to qRT-PCR thereby increasing the testing capacity of medical microbiological laboratories and relieving the existent PCR platforms for routine non-SARS-CoV-2 diagnostic testing.

scholarly journals Rapid, sensitive and specific SARS coronavirus-2 detection: a multi-center comparison between standard qRT-PCR and CRISPR based DETECTR.

2020 ◽  
Author(s):  
Eelke Brandsma ◽  
Han JMP Verhagen ◽  
Thijs J.W. van de Laar ◽  
Eric C.J. Claas ◽  
Marion Cornelissen ◽  
...  
Keyword(s):  
Point Of Care ◽  
Diagnostic Testing ◽  
Added Value ◽  
N Gene ◽  
Analytical Sensitivity ◽  
Qrt Pcr ◽  
Negative Results ◽  
Point Of Care Test ◽  
Ribonucleoprotein Complexes ◽  
Large Patient

Recent advances in CRISPR-based diagnostics suggest that DETECTR, a combination of isothermal reverse transcriptase loop mediated amplification (RT-LAMP) and subsequent Cas12 bystander nuclease activation by amplicon targeting ribonucleoprotein complexes, could be a faster and cheaper alternative to qRT-PCR without sacrificing sensitivity/specificity. Here we compare qRT-PCR with DETECTR to diagnose COVID-19 on 378 patient samples and report a 95% reproducibility. Patient sample dilution assays suggest a higher analytical sensitivity of DETECTR compared to qRT-PCR, however, this was not confirmed in a large patient cohort. The data showed that both techniques are equally sensitive in detecting SARS-CoV-2 providing an added value of DETECTR to the currently used qRT-PCR platforms. For DETECTR, different gRNAs can be used simultaneously to obviate negative results due to mutations in N-gene. Lateral flow strips, suitable as a point of care test (POCT), showed a 100% correlation to the high-throughput DETECTR assay. Importantly, DETECTR was 100% specific for SARS-CoV-2 and did not detect other human coronaviruses. As there is no need for specialized equipment, DETECTR could be rapidly implemented as a complementary technically independent approach to qRT-PCR thereby increasing the testing capacity of medical microbiological laboratories and relieving the existent PCR-platforms for routine non- SARS-CoV-2 diagnostic testing.

scholarly journals Cattle rabies: the effect of clinical evolution, viral genetic lineage, and viral load on the severity of histological lesions

2020 ◽  
Vol 40 (4) ◽  
pp. 227-233
Author(s):  
Claudia S. Wisser ◽  
André Thaler Neto ◽  
Helena B.C.R. Batista ◽  
Enio Mori ◽  
Maria E.R. Chierato ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Reverse Transcriptase ◽  
Fluorescent Antibody ◽  
Inflammatory Lesion ◽  
Genetic Lineage ◽  
Fluorescent Antibody Technique ◽  
Chain Reaction ◽  
Antibody Technique ◽  
Qrt Pcr ◽  
Polymerase Chain

ABSTRACT: Our objective was the characterization and staging of histological lesions in different anatomical sites of the central nervous system (CNS) of rabid cattle. The severity of the lesions was compared with the clinical stages of the disease, the variants of viral isolates, and with the load of virus. Thirty-one spontaneously affected rabid cattle the state of Santa Catarina underwent clinical follow-up and were eventually necropsied. CNS tissues were sampled and submitted to direct fluorescent antibody technique (DFAT), immunohistochemistry (IHC), routine histopathology with hematoxylin and eosin stain (HE), reverse transcriptase polymerase chain reaction (RT-PCR), and polymerase chain reaction in quantitative reverse transcriptase in real time (qRT-PCR). Affected cattle were allotted in four groups according to their clinical stage when euthanized: G1, euthanized while standing; G2, euthanized when in sternal recumbence; G3, euthanized when in lateral recumbence; and G4, affected cattle with natural death. In order to evaluate the degree of severity of the lesions and the presence of Negri bodies (NBs), the brain was sectioned at 9 sites. Additionally, spinal cord and trigeminal ganglion sections were examined. The intensity of the lesions was graded as either absent, mild, moderate, or marked, and the presence or absence of the NBs was noted. Histological lesions were characterized by lymphocytic and monocytic meningoencephalitis with NBs in 28 cases. In all analyzed groups, intensities of histological lesions ranging from mild to severe were observed. Brain regions with the highest inflammatory lesion intensity were the medulla at the level of obex, followed by the colliculus and thalamus. NBs were observed in a higher percentage in the cerebellum, followed by medulla at the obex level, striatum complex, and frontal telencephalon. The duration of the clinical course of the disease did not influence the intensity of the inflammatory lesion, but it did influence the presence of NBs, with a higher percentage of these inclusions in cattle that died naturally than in euthanized cattle. All isolated rhabdovirus included in this study were genetically compatible with samples from hematophagous bats Desmodus rotundus. The evaluation by qRT-PCR did not demonstrate a correlation between lesion intensity and the amount of virus.

scholarly journals Experience With Pretravel Testing for SARS-CoV-2 at an Academic Medical Center

2021 ◽  
Vol 8 ◽  
pp. 237428952110102
Author(s):  
Katherine L. Imborek ◽  
Matthew D. Krasowski ◽  
Paul Natvig ◽  
Anna E. Merrill ◽  
Daniel J. Diekema ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Severe Acute Respiratory Syndrome ◽  
Reverse Transcriptase ◽  
Medical Center ◽  
Academic Medical Center ◽  
Immunoglobulin M ◽  
Chain Reaction ◽  
Academic Medical ◽  
Polymerase Chain ◽  
Positive Results

International travel has been a significant factor in the coronavirus disease 2019 pandemic. Many countries and airlines have implemented travel restrictions to limit the spread of the causative agent, severe acute respiratory syndrome coronavirus-2. A common requirement has been a negative reverse-transcriptase polymerase chain reaction performed by a clinical laboratory within 48 to 72 hours of departure. A more recent travel mandate for severe acute respiratory syndrome coronavirus-2 immunoglobulin M serology testing was instituted by the Chinese government on October 29, 2020. Pretravel testing for severe acute respiratory syndrome coronavirus-2 raises complications in terms of cost, turnaround time, and follow-up of positive results. In this report, we describe the experience of a multidisciplinary collaboration to develop a workflow for pretravel severe acute respiratory syndrome coronavirus-2 reverse-transcriptase polymerase chain reaction and immunoglobulin M serology testing at an academic medical center. The workflow primarily involved self-payment by patients and preferred retrieval of results by the patient through the electronic health record patient portal (Epic MyChart). A total of 556 unique patients underwent pretravel reverse-transcriptase polymerase chain reaction testing, with 13 (2.4%) having one or more positive results, a rate similar to that for reverse-transcriptase polymerase chain reaction testing performed for other protocol-driven asymptomatic screening (eg, inpatient admissions, preprocedural) at our medical center. For 5 of 13 reverse-transcriptase polymerase chain reaction positive samples, the traveler had clinical history, prior reverse-transcriptase polymerase chain reaction positive, and high cycle thresholds values on pretravel testing consistent with remote infection and minimal transmission risk. Severe acute respiratory syndrome coronavirus-2 immunoglobulin M was performed on only 24 patients but resulted in 2 likely false positives. Overall, our experience at an academic medical center shows the challenge with pretravel severe acute respiratory syndrome coronavirus-2 testing.

scholarly journals Pendeteksian petanda kepuncaan glioblastoma multiforme

2020 ◽  
Vol 3 (1) ◽  
pp. 39-45
Author(s):  
Yohana Yohana
Keyword(s):  
Polymerase Chain Reaction ◽  
Glioblastoma Multiforme ◽  
Western Blot ◽  
Reverse Transcriptase ◽  
Real Time ◽  
Chain Reaction ◽  
Qrt Pcr ◽  
Polymerase Chain

Glioblastoma multiforme (GBM) adalah tumor otak ganas yang memiliki populasi sel punca kanker yang dapat  mempertahankan formasi tumor. Peranan sel punca kanker telah banyak dipelajari yang memiliki tanggung jawab terhadap resistensi dan rekurensi terapi GBM seperti radiasi dan kemoterapi. Beberapa petanda kepuncaan dapat dipakai diantaranya CD133, Nestin, A2B5, CD44, SOX2 and OCT4. Pemeriksaan histopatologi terhadap jaringan tumor yang dioperasi menjadi standar baku untuk menentukan derajat, tingkat keganasan, dan prognosis keganasan. Namun di sisi lain, kehadiran populasi sel punca yang memiliki sifat mampu memperbaharui diri dan mampu menginduksi pembentukan tumor memerlukan pemeriksaan yang lebih mendalam mengenai karakteristik biologi sel tumor. Pemeriksaan  sel punca dilakukan menggunakan flowcytometry dan imunohistokimia. Pemeriksaan petanda kepuncaan glioblastoma dilakukan dengan quantitative Reverse Transcriptase Real Time Polymerase Chain Reaction (qRT-PCR), Enzyme Linked Immunoabsorbent Assay (ELISA), Western Blot, Imunohistokimia dan flowcytometry. Petanda CD133 ditemukan ekspresinya meningkat pada berbagai pemeriksaan. CD133 digunakan sebagai prognostik GBM.

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