ABSTRACT
Many virus lysis/transport buffers used in molecular diagnostics, including the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA, contain guanidine-based chaotropic salts, primarily guanidine hydrochloride (GuHCl) or guanidine isothiocyanate (GITC). Although the virucidal effects of GuHCl and GITC alone against some enveloped viruses have been established, standardized data on their optimum virucidal concentrations against SARS-CoV-2 and effects on viral RNA stability are scarce. Thus, we aimed to determine the optimum virucidal concentrations of GuHCl and GITC against SARS-CoV-2 compared to influenza A virus (IAV), another enveloped respiratory virus. We also evaluated the effectiveness of viral RNA stabilization at the determined optimum virucidal concentrations under high-temperature conditions (35°C) using virus-specific real-time reverse transcription polymerase chain reaction. Both viruses were potently inactivated by 1.0 M GITC and 2.5 M GuHCl, but the GuHCl concentration for efficient SARS-CoV-2 inactivation was slightly higher than that for IAV inactivation. GITC showed better viral RNA stability than GuHCl at the optimum virucidal concentrations. An increased concentration of GuHCl or GITC increased viral RNA degradation at 35°C. Our findings highlight the need to standardize GuHCl and GITC concentrations in virus lysis/transport buffers and the potential application of these guanidine-based salts alone as virus inactivation solutions in SARS-CoV-2 and IAV molecular diagnostics.
Subject(s)
Guanidine , Influenza A virus , RNA, Viral , SARS-CoV-2 , Specimen Handling , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , Influenza A virus/drug effects , Influenza A virus/genetics , Guanidine/pharmacology , Guanidine/chemistry , RNA, Viral/genetics , Humans , Specimen Handling/methods , Genome, Viral , COVID-19/virology , COVID-19/diagnosis , Chlorocebus aethiops , Vero Cells , Virus Inactivation/drug effects , Animals , RNA Stability/drug effects , Containment of Biohazards , Guanidines/pharmacology , Guanidines/chemistry , Salts/pharmacology , Salts/chemistryABSTRACT
Since being reported in 1979 and 2006, indirect fluorescent antibody (IFA) tests have not been reported to detect bovine viral diarrhea virus (BVDV) antibodies to our knowledge. Thus, we re-evaluated the efficacy and usefulness of IFA tests for BVDV serology. We tested 4 combinations of 2 antibody conjugates (fluorescein isothiocyanate [FITC]-conjugated rabbit IgG anti-bovine IgG; rabbit IgG F(ab')2 fragment anti-bovine IgG [F(ab')2 FITC-IgG]) and 2 washing solutions (PBS; carbonate-bicarbonate-buffered saline [CBBS]) to evaluate the specificity of an IFA test for BVDV. We compared the sensitivity of the optimal combination with virus neutralization (VN) tests and an ELISA, and compared IFA with VN titers against different genotype (subgenotype) strains. For the F(ab')2 FITC-IgG/CBBS combination, only 1 of the 156 (0.6%) 4-fold diluted cattle sera resulted in a nonspecific reaction; other combinations led to a much higher incidence (22.9-37.2%). For the F(ab')2 FITC-IgG/CBBS combination, IFA detection rates were identical (36 of 59) for BVDV1 and BVDV2 genotypes, and IFA titers against them were strongly correlated (r = 0.99). The antibody-detection rates of the IFA tests were almost identical to those of VN tests and the ELISA (κ: 0.96 and 0.89, respectively). The IFA titers against 4 strains (BVDV1a, BVDV1j, BVDV2a, and an unidentified strain) were similar, 1,024 to ≥4,096, although the VN titers were different. Thus, our IFA tests were specific and sensitive, and more useful than VN tests given that the IFA tests could evaluate the immune status of cattle using a representative strain, regardless of genotype (subgenotype).
Subject(s)
Bovine Virus Diarrhea-Mucosal Disease , Cattle Diseases , Diarrhea Virus 1, Bovine Viral , Diarrhea Viruses, Bovine Viral , Cattle , Animals , Rabbits , Fluorescein-5-isothiocyanate , Diarrhea Viruses, Bovine Viral/genetics , Diarrhea Virus 1, Bovine Viral/genetics , Antibodies, Viral , Immunoglobulin G , Diarrhea/veterinary , Bovine Virus Diarrhea-Mucosal Disease/diagnosisABSTRACT
Objective Abdominal ultrasonography (AUS) is used to screen for abdominal diseases owing to its low cost, safety, and accessibility. However, the detection rate of pancreatic disease using AUS is unsatisfactory. We evaluated the visualization area of the pancreas and the efficacy of manipulation techniques for AUS with fusion imaging. Methods Magnetic resonance imaging (MRI) volume data were obtained from 20 healthy volunteers in supine and right lateral positions. The MRI volume data were transferred to an ultrasound machine equipped with a fusion imaging software program. We evaluated the visualization area of the pancreas before and after postural changes using AUS with fusion imaging and assessed the liquid-filled stomach method using 500 ml of de-aerated water in 10 randomly selected volunteers. Patients This study included 20 healthy volunteers (19 men and 1 woman) with a mean age of 33.0 (21-37.5) years old. Results Fusion imaging revealed that the visualization area of the entire pancreas using AUS was 55%, which significantly improved to 75% with a postural change and 90% when using the liquid-filled stomach method (p=0.043). Gastrointestinal gas is the main obstacle for visualization of the pancreas. Conclusion Fusion imaging objectively demonstrated that manipulation techniques can improve pancreatic visualization.
ABSTRACT
(1) Background: There is controversy regarding stent placement for unresectable malignant hilar biliary obstruction (UMHBO). We mainly use the partial stent-in-stent (PSIS) method with an uncovered self-expandable metallic stent (UCSEMS) based on the drainage area and patency period. In this study, we investigated the usefulness and safety of the PSIS method. (2) Methods: In total, 59 patients who underwent the PSIS method for UMHBO at our hospital were included in the study. The technical success rate, clinical success rate, time to recurrent biliary obstruction (TRBO) and overall survival (OS) from the first placement, factors affecting TRBO and OS, and early complications within 30 days after the procedure were evaluated retrospectively. (3) Results: The technical and clinical success rates were 100% and 96.6%, respectively, with a TRBO of 121 days [95% confidence interval: 82-231] and an OS of 194 days [95% confidence interval: 113-305] after the first placement. Early complications occurred in nine patients (15.3%), including five cases of cholangitis, three cases of pancreatitis, and one case of cholecystitis. (4) Conclusions: The PSIS method for UMHBO is safe and useful with high technical and clinical success rates.