scholarly journals Immunohistochemical typing of amyloid in fixed paraffin-embedded samples by an automatic procedure: Comparison with immunofluorescence data on fresh-frozen tissue

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256306
Author(s):  
Antonella Barreca ◽  
Emanuel Bottasso ◽  
Francesca Veneziano ◽  
Manuela Giarin ◽  
Alberto Nocifora ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gold Standard ◽  
Retrospective Cohort ◽  
Low Cost ◽  
Amorphous Material ◽  
Immunogold Labeling ◽  
Frozen Tissue ◽  
Fresh Frozen ◽  
Antibody Panel ◽  
Automated Platform

Amyloidosis comprises a spectrum of disorders characterized by the extracellular deposition of amorphous material, originating from an abnormal serum protein. The typing of amyloid into its many variants represents a pivotal step for a correct patient management. Several methods are currently used, including mass spectrometry, immunofluorescence, immunohistochemistry, and immunogold labeling. The aim of the present study was to investigate the accuracy and reliability of immunohistochemistry by means of a recently developed amyloid antibody panel applicable on fixed paraffin-embedded tissues in an automated platform. Patients with clinically and pathologically proven amyloidosis were divided into two cohorts: a pilot one, which included selected amyloidosis cases from 2009 to 2018, and a retrospective one (comprising all consecutive amyloidosis cases analyzed between November 2018 and May 2020). The above-referred panel of antibodies for amyloid classification was tested in all cases using an automated immunohistochemistry platform. When fresh-frozen material was available, immunofluorescence was also performed. Among 130 patients, a total of 143 samples from different organs was investigated. They corresponded to 51 patients from the pilot cohort and 79 ones from the retrospective cohort. In 82 cases (63%), fresh-frozen tissue was tested by immunofluorescence, serving to define amyloid subtype only in 30 of them (36.6%). On the contrary, the automated immunohistochemistry procedure using the above-referred new antibodies allowed to establish the amyloid type in all 130 cases (100%). These included: ALλ (n = 60, 46.2%), ATTR (n = 29, 22.3%), AA (n = 19, 14.6%), ALκ (n = 18, 13.8%), ALys (n = 2, 1.5%), and Aβ2M amyloidosis (n = 2, 1.5%). The present immunohistochemistry antibody panel represents a sensitive, reliable, fast, and low-cost method for amyloid typing. Since immunohistochemistry is available in most pathology laboratories, it may become the new gold standard for amyloidosis classification, either used alone or combined with mass spectrometry in selected cases.

Fresh frozen tissue staining with CODEX tagged antibody panel v1 (protocols.io.4jngume)

protocols.io ◽  
2019 ◽  
Author(s):  
Yury Goltsev ◽  
Nikolay Samusik ◽  
Julia Kennedy ◽  
Salil Bhate ◽  
Matthew Hale ◽  
...  
Keyword(s):  
Frozen Tissue ◽  
Fresh Frozen ◽  
Antibody Panel

Fresh frozen tissue staining with CODEX tagged antibody panel v1 (protocols.io.2qpgdvn)

protocols.io ◽  
2019 ◽  
Author(s):  
Yury Goltsev ◽  
Nikolay Samusik ◽  
Julia Kennedy ◽  
Salil Bhate ◽  
Matthew Hale ◽  
...  
Keyword(s):  
Frozen Tissue ◽  
Fresh Frozen ◽  
Antibody Panel

Glass Knife Geometry as Seen by the SEM

1971 ◽  
Vol 29 ◽  
pp. 454-455
Author(s):  
J. Temple Black
Keyword(s):  
Low Cost ◽  
Amorphous Material ◽  
Stress Concentrations ◽  
Basic Tool ◽  
Tool Materials ◽  
Optical Inspection ◽  
Surface Flaws ◽  
Slip Planes ◽  
Glass Knife ◽  
Diamond Knife

In ultramicrotomy, the two basic tool materials are glass and diamond. Glass because of its low cost and ease of manufacture of the knife itself is still widely used despite the superiority of diamond knives in many applications. Both kinds of knives produce plastic deformation in the microtomed section due to the nature of the cutting process and microscopic chips in the edge of the knife. Because glass has no well defined slip planes in its structure (it's an amorphous material), it is very strong and essentially never fails in compression. However, surface flaws produce stress concentrations which reduce the strength of glass to 10,000 to 20,000 psi from its theoretical or flaw free values of 1 to 2 million psi. While the microchips in the edge of the glass or diamond knife are generally too small to be observed in the SEM, the second common type of defect can be identified. This is the striations (also termed the check marks or feathers) which are always present over the entire edge of a glass knife regardless of whether or not they are visable under optical inspection. These steps in the cutting edge can be observed in the SEM by proper preparation of carefully broken knives and orientation of the knife, with respect to the scanning beam.

scholarly journals A low-cost mass spectrometry-based approach for quantifying purines in placental explants

2021 ◽  
Vol 460 ◽  
pp. 116490
Author(s):  
Ruslan Rodriguez ◽  
Igor Konovets ◽  
Serhii Ralchenko ◽  
Maxsim Kharkhota ◽  
Andrij Kostyuk ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Low Cost

scholarly journals Superiority of MALDI-TOF Mass Spectrometry over Real-Time PCR for SARS-CoV-2 RNA Detection

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 730
Author(s):  
Magda Rybicka ◽  
Ewa Miłosz ◽  
Krzysztof Piotr Bielawski
Keyword(s):  
Mass Spectrometry ◽  
Gold Standard ◽  
Viral Genome ◽  
False Negative ◽  
Rt Pcr ◽  
Rna Detection ◽  
Maldi Tof ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Test

At present, the RT-PCR test remains the gold standard for early diagnosis of SARS-CoV-2. Nevertheless, there is growing evidence demonstrating that this technique may generate false-negative results. Here, we aimed to compare the new mass spectrometry-based assay MassARRAY® SARS-CoV-2 Panel with the RT-PCR diagnostic test approved for clinical use. The study group consisted of 168 suspected patients with symptoms of a respiratory infection. After simultaneous analysis by RT-PCR and mass spectrometry methods, we obtained discordant results for 17 samples (10.12%). Within fifteen samples officially reported as presumptive positive, 13 were positive according to the MS-based assay. Moreover, four samples reported by the officially approved RT-PCR as negative were positive in at least one MS assay. We have successfully demonstrated superior sensitivity of the MS-based assay in SARS-CoV-2 detection, showing that MALDI-TOF MS seems to be ideal for the detection as well as discrimination of mutations within the viral genome.

scholarly journals A set of simple methods for detection and extraction of laminarinase

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ananthamurthy Koteshwara ◽  
Nancy V. Philip ◽  
Jesil Mathew Aranjani ◽  
Raghu Chandrashekhar Hariharapura ◽  
Subrahmanyam Volety Mallikarjuna
Keyword(s):  
Ammonium Sulfate ◽  
Ammonium Sulphate ◽  
Gold Standard ◽  
Direct Detection ◽  
Low Cost ◽  
Direct Analysis ◽  
Reducing Sugar ◽  
Ammonium Sulfate Precipitation ◽  
Simple Method ◽  
Functional Step

AbstractA carefully designed ammonium sulfate precipitation will simplify extraction of proteins and is considered to be a gold standard among various precipitation methods. Therefore, optimization of ammonium sulfate precipitation can be an important functional step in protein purification. The presence of high amounts of ammonium sulphate precludes direct detection of many enzymatically active proteins including reducing sugar assays (e.g. Nelson-Somogyi, Reissig and 3,5-dinitrosalicylic acid methods) for assessing carbohydrases (e.g. laminarinase (β (1–3)-glucanohydrolase), cellulases and chitinases). In this study, a simple method was developed using laminarin infused agarose plate for the direct analysis of the ammonium sulphate precipitates from Streptomyces rimosus AFM-1. The developed method is simple and convenient that can give accurate results even in presence of ammonium sulfate in the crude precipitates. Laminarin is a translucent substrate requiring the use of a stain to visualize the zones of hydrolysis in a plate assay. A very low-cost and locally available fluorescent optical fabric brightener Tinopal CBS-X has been used as a stain to detect the zones of hydrolysis. We also report simple methods to prepare colloidal chitin and cell free supernatant in this manuscript.

scholarly journals A20 DIAGNOSTIC ACCURACY OF A LOW COST, WIDELY AVAILABLE TEST STRIP FOR PREDICTING A POSITIVE FECAL CALPROTECTIN TEST

2021 ◽  
Vol 4 (Supplement_1) ◽  
pp. 210-212
Author(s):  
R Trasolini ◽  
S Wong ◽  
B Salh
Keyword(s):  
Sample Size ◽  
Likelihood Ratio ◽  
Gold Standard ◽  
Low Cost ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Rapid Test ◽  
Test Strip ◽  
Fecal Calprotectin ◽  
Type I

Abstract Background Fecal calprotectin is a non-invasive test of colonic inflammation used for monitoring inflammatory bowel disease activity and for risk stratifying non-specific colonic symptoms. Calprotectin is a leukocyte specific enzyme. A similar test, leukocyte esterase is used to detect leukocytes in urine and is widely available as a low-cost point-of-care test strip. We hypothesize that an unmodified version of the urine test strip would be highly accurate in predicting a positive fecal calprotectin test in a real world sample of patients. Aims To explore a low cost, rapid alternative to the fecal calprotectin test Methods All inpatient and outpatient stool samples tested for calprotectin by the Vancouver General Hospital laboratory from February 2020 to November 2020 were included prospectively. Samples were simultaneously tested for fecal leukocyte esterase using an unmodified Roche Cobas Chemstrip urinalysis test strip by central lab personnel. An identical aliquot was sent to LifeLabs for calprotectin as per standard protocol. All samples were suspended in buffer using established laboratory protocols prior to testing. Fecal leukocyte esterase results were reported as 0–4+ based on visual interpretation, calprotectin results were reported as mcg/g of stool. REB review and approval was obtained prior to data collection. Sensitivity, Specificity and AUROC were calculated using Microsoft Excel and JROCFIT. Results 26 samples were collected. Using a fecal calprotectin greater than 120 mcg/g as a gold standard an AUROC of 0.89 (SE= .06) was calculated. A leukocyte esterase reading of 2+ or greater had the best test characteristics based on ROC curve analysis. Using this cutoff, 21/26 samples were concordant, giving an accuracy of 80.8%, sensitivity of 90.9% and specificity of 73.3%. Positive likelihood ratio was 8.07 and negative likelihood ratio was 0.29. Assuming an AUROC of 0.8, the sample size N=26 is 90% powered (β=0.9) to predict the true AUROC within 0.1 with a type I error rate of .05 (α<.05). Conclusions This study suggests application of a prepared stool sample to a urinalysis test strip gives a result highly predictive of a positive fecal calprotectin test. Further results are being collected prospectively to improve the robustness of these preliminary data. Secondary outcomes including comparison to endoscopy and biopsy results where available are planned if an adequate sample size can be accrued. Future studies justifying independent clinical use of leukocyte esterase would require a common gold standard comparator such as endoscopy. Fecal calprotectin testing is not universally insured and is not available as a rapid test strip. Use of fecal leukocyte esterase may reduce costs and shorten time to results if proven to be independently reliable. Funding Agencies None

Impact of methodical guidelines of gastric scintigraphy on patients’ radiation exposure

2021 ◽  
Vol 75 (2) ◽  
pp. 159-164
Author(s):  
Martina Horváthová ◽  
Zuzana Bárdyová ◽  
Darina Budošová ◽  
Rastislav Husťak
Keyword(s):  
Gastric Emptying ◽  
Radiation Exposure ◽  
Gold Standard ◽  
Retrospective Cohort ◽  
Noninvasive Method ◽  
Lower Intensity ◽  
Medicine Department ◽  
Nuclear Medicine Department ◽  
Gastric Emptying Scintigraphy ◽  
Gastric Scintigraphy

Introduction: Gastric emptying scintigraphy (GES) is a safe, noninvasive method for assessing the ability of the stomach to empty which has been used clinically for many years. It is considered as a “gold standard” to assess gastric emptying of both solids and liquids allowing assessment of early, mid and late emptying, each of which may be altered by pathology. The aim of the study was to analyse standard diagnostic approach and evaluate patients` radiation exposure, who underwent GES in Slovakia. Methods: A retrospective cohort study included 55 patients from 2 departments of nuclear medicine (department A, B). Patients’ radiation exposure was determined by dosimetry program IDAC-Dose2.1. The radiopharmaceutical 99mTc-DTPA, always with the same activity, was applied orally to patients at Department B. The applied activity of the radiopharmaceutical at GES was 185 MBq. The radiopharmaceutical 99mTc MAA, with various activity, was applied orally to patients at Department A. Results: According to ICRP60, the eff ective dose (ED) of every patient undergoing GES was 0.77 mSv and, according to ICRP103, the dose was 0.836 mSv at Department B. Patients at Department A were exposed to ionizing radiation with 5-times lower intensity, compared with patients at Department B. It was caused by radiopharmaceutical activity correction. The ED medians according to ICRP60, and according to ICRP103 were 0.167 mSv (range 0.105–0.208 mSv) and 0.181 mSv (range 0.113–0.226 mSv) at Department A, respectively. Discussion: Adequate correction of applied radiopharmaceutical activity is an essential part of GES guidelines and in accordance with ALARA principles. For the accuracy of GES examination, it is necessary to follow a standard 4-hour protocol and an approach which ensures full-featured utilization of the examination while decreasing patient`s radiation exposure. Conclusion: The results of our study show relatively low ED associated with GES, but also confi rm that the GES methodology significantly affects the patient`s radiation exposure

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