scholarly journals Genotype classification and fluorescence visual identification of the Rhizoma Paridis of Paris polyphylla var. yunnanensis based on the SNPs of ITS sequence 

2020 ◽  
Author(s):  
Chi Gao ◽  
Kaiyuan Zhang ◽  
Qinghe Wang ◽  
Ling Zhao ◽  
Rong Chen ◽  
...  
Keyword(s):  
Internal Transcribed Spacer ◽  
False Negative ◽  
Identification System ◽  
Accurate Identification ◽  
Negative Results ◽  
Visual Identification ◽  
False Negative Results ◽  
Paris Polyphylla ◽  
Green Fluorescent ◽  
First Time

Abstract A fluorescent visual identification system of Paris polyphylla var. yunnanensis was established based on internal transcribed spacer barcoding. It is proposed for the first time that P. polyphylla var. yunnanensis should be divided into two types of genotypes: YN-I and YN-II according to single nucleotide polymorphism of internal transcribed spacer. In order to avoid false-negative results, two pairs of specific primers for YN-I and YN-II were designed, respectively, and specific visual fluorescent identification systems was established by SYBR Green I fluorescent dye was directly introduced into the PCR system which can be observed directly with the naked eye for the green fluorescent color of PCR system. Therefrom, it has realized the rapid and directly visual identification of two genotypes of P. polyphylla var. yunnanensis from its common nine adulterants. This study proposed for the first time the existence of different genotypes on the legal basis of Rhizoma Paridis, and provided a model for the accurate identification of different genotypes.

Genotype Classification and Fluorescence Visual Identification of the Rhizoma Paridis of Paris Polyphylla Var. Yunnanensis based on the SNPs of ITS Sequence

2020 ◽  
Author(s):  
Chi Gao ◽  
Kaiyuan Zhang ◽  
Qinghe Wang ◽  
Ling Zhao ◽  
Rong Chen ◽  
...  
Keyword(s):  
Internal Transcribed Spacer ◽  
False Negative ◽  
Identification System ◽  
Accurate Identification ◽  
Negative Results ◽  
Visual Identification ◽  
False Negative Results ◽  
Paris Polyphylla ◽  
Green Fluorescent ◽  
First Time

Abstract A fluorescent visual identification system of Paris polyphylla var. yunnanensis was established based on internal transcribed spacer barcoding. It is proposed for the first time that P. polyphylla var. yunnanensis should be divided into two types of genotypes: YN-I and YN-II according to single nucleotide polymorphism of internal transcribed spacer. In order to avoid false-negative results, two pairs of specific primers for YN-I and YN-II were designed, respectively, and specific visual fluorescent identification systems was established by SYBR Green I fluorescent dye was directly introduced into the PCR system which can be observed directly with the naked eye for the green fluorescent color of PCR system. Therefrom, it has realized the rapid and directly visual identification of two genotypes of P. polyphylla var. yunnanensis from its common nine adulterants. This study proposed for the first time the existence of different genotypes on the legal basis of Rhizoma Paridis, and provided a model for the accurate identification of different genotypes.

scholarly journals Importance of Adequate qPCR Controls in Infection Control

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2373
Author(s):  
Matthew Oughton ◽  
Ivan Brukner ◽  
Shaun Eintracht ◽  
Andreas I. Papadakis ◽  
Alan Spatz ◽  
...  
Keyword(s):  
Infection Control ◽  
False Negative ◽  
Significant Proportion ◽  
Control Measures ◽  
Negative Results ◽  
Minimal Sample ◽  
Infection Control Measures ◽  
False Negative Results ◽  
Quantitative Sample ◽  
First Time

Respiratory screening assays lacking Sample Adequacy Controls (SAC) may result in inadequate sample quality and thus false negative results. The non-adequate samples might represent a significant proportion of the total performed tests, thus resulting in sub-optimal infection control measures with implications that may be critical during pandemic times. The quantitative sample adequacy threshold can be established empirically, measuring the change in the frequency of positive results, as a function of the numerical value of “sample adequacy”. Establishing a quantitative threshold for SAC requires a big number/volume of tests to be analyzed in order to have a statistically valid result. Herein, we are offering for the first time clear clinical evidence that a subset of results, which did not pass minimal sample adequacy criteria, have a significantly lower frequency of positivity compared with the “adequate” samples. Flagging these results and/or re-sampling them is a mitigation strategy, which can dramatically improve infection control measures.

scholarly journals Detection of a Giardia lamblia coproantigen by using a commercially available immunoenzymatic assay, in Belo Horizonte, Brazil

1999 ◽  
Vol 41 (3) ◽  
pp. 151-154 ◽  
Author(s):  
Míriam Oliveira e ROCHA ◽  
Rômulo Teixeira de MELLO ◽  
Tânia Mara Pinto Dabés GUIMARÃES ◽  
Vicente de Paulo Coelho Peixoto de TOLEDO ◽  
Maria da Conceição Carneiro Gonçalves MOREIRA ◽  
...  
Keyword(s):  
Giardia Lamblia ◽  
Intestinal Parasites ◽  
False Negative ◽  
Good Alternative ◽  
Fecal Examination ◽  
Negative Results ◽  
False Negative Results ◽  
Belo Horizonte ◽  
First Time ◽  
Immunoenzymatic Assay

It is known that fecal examination to detect Giardia lamblia cysts or trophozoites produces a high percentage of false-negative results. A commercially available immunoenzymatic assay (ProSpecT Giardia Microplate Assay, Alexon, Inc., BIOBRÁS) to detect G. lamblia specific coproantigen was evaluated for the first time in Brazil. A total of 90 specimens were tested. Each specimen was first tested as unpreserved stool, and then it was preserved in 10% Formalin to be tested 2 months later. The assay was able to identify all the 30 positive patients (sensitivity = 100.0%) by visual or spectrophotometric examination in the unpreserved specimens and was negative in 57 of the 60 patients without G. lamblia (specificity = 95.0%). The assay identified 27 of the 30 positive patients (sensitivity = 90.0%) and was negative in 59 of the 60 negatives (specificity = 98.3%) in the preserved stools according to both readings. A marked difference was observed in the optical densities in both groups, preserved and unpreserved stools, when the G. lamblia-positive specimens were compared to the negative or positive for other intestinal parasites than G. lamblia. The assay seems a good alternative for giardiasis diagnosis, especially when the fecal examination was repeatedly negative and the patient presents giardiasislike symptoms.

scholarly journals Lateral Flow Immunochromatography Assay for Detection of Furosemide in Slimming Health Foods

Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2041
Author(s):  
Yingying Li ◽  
Haihuan Xie ◽  
Jin Wang ◽  
Xiangmei Li ◽  
Zhili Xiao ◽  
...  
Keyword(s):  
Au Nanoparticles ◽  
Limit Of Detection ◽  
False Negative ◽  
Sample Pretreatment ◽  
Lateral Flow ◽  
Initial Screening ◽  
Negative Results ◽  
False Negative Results ◽  
High Consistency ◽  
First Time

In recent years, furosemide has been found to be abused in slimming health foods. There is an urgent need for a simpler, faster method for detecting furosemide in slimming health foods. In this study, a rapid, convenient and sensitive lateral flow immunochromatography (LFIA) based on Au nanoparticles (AuNPs) was established for the first time. Under optimal conditions, the qualitative limit of detection (LOD) of the AuNPs-based LFIA was 1.0~1.2 μg/g in slimming health foods with different substrates. AuNPs-LFIA could specifically detect furosemide within 12 min (including sample pretreatment) and be read by the naked eye. The developed AuNPs-LFIA showed high consistency with liquid chromatography with tandem mass spectrometry (LC-MS/MS), and no false positive or false negative results were found in spiked slimming health foods, proving that the AuNPs-LFIA should be accurate and reliable. The AuNPs-LFIA reported here provides a serviceable analytical tool for the on-site detection and rapid initial screening of furosemide for the first time.

Critical Evaluation of Impedance Phlebography for the Diagnosis of Deep Vein Thrombosis

1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel
Keyword(s):  
Deep Vein Thrombosis ◽  
False Positive ◽  
False Negative ◽  
Critical Evaluation ◽  
Original Method ◽  
Vein Thrombosis ◽  
Negative Results ◽  
False Negative Results ◽  
Deep Vein ◽  
Positive Results

SummaryIn order to evaluate its daily variability and reliability, impedance phlebography was performed daily or on alternate days on 61 patients with deep vein thrombosis, of whom 47 also had 125I-fibrinogen uptake tests and 22 had radiographic venography. The results showed that impedance phlebography was highly variable and poorly reliable. False positive results were noted in 8 limbs (18%) and false negative results in 3 limbs (7%). Despite its being simple, rapid and noninvasive, its clinical usefulness is doubtful when performed according to the original method.

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

Detection of Streptococcus pneumoniae in Sputum Samples by Real- Time PCR.

2020 ◽  
Vol 18 ◽  
Author(s):  
Pegah Shakib ◽  
Mohammad Reza Zolfaghari
Keyword(s):  
Streptococcus Pneumoniae ◽  
Real Time ◽  
Real Time Pcr ◽  
False Negative ◽  
Cross Sectional Study ◽  
Laboratory Culture ◽  
Cross Sectional ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Method

Background: Conventional laboratory culture-based methods for diagnosis of Streptococcus pneumoniae are time-consuming and yield false negative results. Molecular methods including real-time (RT)-PCR rapid methods and conventional PCR due to higher sensitivity and accuracy have been replaced instead traditional culture assay. The aim of the current study was to evaluate lytA gene for detection of Streptococcus pneumoniae in the cerebrospinal fluid of human patients with meningitis using real-time PCR assay. Material and Methods: In this cross-sectional study, a total of 30 clinical specimens were collected from patients in a period from September to December 2018. In order to evaluate the presence of lytA gene, conventional and real-time PCR methods were used without culture. Results: From 30 sputum samples five (16.66%) isolates were identified as S. pneumoniae by lytA PCR and sequencing. Discussion: In this research, an accurate and rapid real-time PCR method was used, which is based on lytA gene for diagnosis of bacteria so that it can be diagnosed. Based on the sequencing results, the sensitivity for detection of lytA gene was 100% (5/5).

COVID-19: how nuclear medicine can provide a differential diagnosis in very dubious case

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Maria Silvia De Feo ◽  
Viviana Frantellizzi ◽  
Giuseppe De Vincentis
Keyword(s):  
Infectious Disease ◽  
Differential Diagnosis ◽  
Ct Scan ◽  
Imaging Technique ◽  
False Negative ◽  
Clinical Signs ◽  
Negative Results ◽  
Infectious Disease Department ◽  
False Negative Results ◽  
99Mtc Hmpao

Background: We present the case of a 55-year-old woman, admitted to the Infectious Disease Department of Policlinico Umberto I, Rome, in mid-March 2020, with suspicion of COVID-19 infection. Objective: The rRT-PCR was negative and the following CT scan, performed to exclude false-negative results and help diagnosis, was inconclusive. Methods: It was decided to submit the patient to 99mTc-HMPAO-labelled leukocyte scan. Results: This exam led to the diagnosis of infective endocarditis. Conclusion: In the present pandemic scenario, 99mTc-HMPAO-labelled leukocyte scan represents a reliable imaging technique for differential diagnosis with COVID-19 in patients with confusing clinical signs, possible false-negative rRT-PCR results and inconclusive CT scan.

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