Quantitative SARS-CoV-2 Spike Antibody Response in COVID-19 Patients Using Three Fully Automated Immunoassays and a Surrogate Virus Neutralization Test.

Quantitative SARS-CoV-2 antibody assays against the spike (S) protein are useful for monitoring immune response after infection or vaccination. We compared the results of three chemiluminescent immunoassays (CLIAs) (Abbott, Roche, Siemens) and a surrogate virus neutralization test (sVNT, GenScript) using 191 sequential samples from 32 COVID-19 patients. All assays detected >90% of samples collected 14 days after symptom onset (Abbott 97.4%, Roche 96.2%, Siemens 92.3%, and GenScript 96.2%), and overall agreement among the four assays was 91.1% to 96.3%. When we assessed time-course antibody levels, the Abbott and Siemens assays showed higher levels in patients with severe disease (p < 0.05). Antibody levels from the three CLIAs were correlated (r = 0.763-0.885). However, Passing-Bablok regression analysis showed significant proportional differences between assays and converting results to binding antibody units (BAU)/mL still showed substantial bias. CLIAs had good performance in predicting sVNT positivity (Area Under the Curve (AUC), 0.959-0.987), with Abbott having the highest AUC value (p < 0.05). SARS-CoV-2 S protein antibody levels as assessed by the CLIAs were not interchangeable, but showed reliable performance for predicting sVNT results. Further standardization and harmonization of immunoassays might be helpful in monitoring immune status after COVID-19 infection or vaccination.

A comparison of diagnostic performance between two quantitative rapid fecal calprotectin assays in detecting active inflammatory bowel disease.

BACKGROUND: Fecal calprotectin (FC) is widely used for the diagnosis and monitoring disease activity of inflammatory bowel disease (IBD). Quantitative rapid assays can be a reliable alternative to the time-consuming assay. This study aimed to evaluate and compare the diagnostic performance of two quantitative rapid FC assays (Ichroma calprotectin, and Buhlmann Quantum blue). METHODS: A total of 192 patients were included in this study; 84 patients with IBD (67 ulcerative colitis and 17 Crohn's disease) and 108 patients with non-IBD. We compared quantitative FC levels in different disease statuses and evaluated the correlation between the FC results of the two FC kits. Diagnostic performances in predicting active IBD were evaluated in reference to different cut-off levels. RESULTS: The FC levels in 45 patients with active IBD as defined by endoscopic score were significantly higher compared to the inactive IBD and other diseases (P<0.05). Although the two assays' results correlated (r = 0.642, P < 0.001), a significant deviation was observed (y (Buhlmannn) = -45.2 +8.9X (Ichroma)). The Diagnostic performances in predicting active IBD were comparable as area under the curve (AUC), 0.812, cut-off, 50, sensitivity, 64.4%, and specificity, 85.0% for iChroma assay and AUC, 0.826, cut-off, 100, sensitivity, 84.4%, and specificity 61.9% for Buhlmann Quantum Blue assay. FC levels using a cut-off of > 250 µg/g confirmed 85.7% (iChroma) and 64.1% (Buhlmann) of active IBD patients. CONCLUSION: The results of the two rapid FC assays iChroma and Buhlmann showed a significant correlation, but the two test results were not interchangeable. With optimized cut-off values, rapid FC tests could be helpful in the diagnosis of IBD and differentiating active IBD from inactive or organic bowel disease.

Comparison of SARS-CoV-2 Antibody Responses and Seroconversion in COVID-19 Patients Using Twelve Commercial Immunoassays.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assays have high clinical utility in managing the pandemic. We compared antibody responses and seroconversion of coronavirus disease 2019 (COVID-19) patients using different immunoassays. METHODS: We evaluated 12 commercial immunoassays, including three automated chemiluminescent immunoassays (Abbott, Roche, and Siemens), three enzyme immunoassays (Bio-Rad, Euroimmun, and Vircell), five lateral flow immunoassays (Boditech Med, SD biosensor, PCL, Sugentech, and Rapigen), and one surrogate neutralizing antibody assay (GenScript) in sequential samples from 49 COVID-19 patients and 10 seroconversion panels. RESULTS: The positive percent agreement (PPA) of assays for a COVID-19 diagnosis ranged from 84.0% to 98.5% for all samples (>14 days after symptom onset), with IgM or IgA assays showing higher PPAs. Seroconversion responses varied across the assay type and disease severity. Assays targeting the spike or receptor-binding domain protein showed a tendency for early seroconversion detection and higher index values in patients with severe disease. Index values from SARS-CoV-2 binding antibody assays (three automated assays, one LFIA, and three EIAs) showed moderate to strong correlations with the neutralizing antibody percentage (r=0.517-0.874), and stronger correlations in patients with severe disease and in assays targeting spike protein. Agreement among the 12 assays was good (74.3%-96.4%) for detecting IgG or total antibodies. CONCLUSIONS: Positivity rates and seroconversion of SARS-CoV-2 antibodies vary depending on the assay kits, disease severity, and antigen target. This study contributes to a better understanding of antibody response in symptomatic COVID-19 patients using currently available assays.

Evaluation of a Newly Developed Rapid Automated Fluorescent Lateral Flow Immunoassay to Detect IgG and IgM Antibodies to Chikungunya Virus.

The ichroma Chikungunya virus (CHIKV) IgG/IgM (Boditech Med Inc., Chuncheon, Korea) is a newly developed rapid lateral flow immunoassay for detection of anti- CHIKV-IgG/IgM. This study conducted with thirty-six anti-CHIKV IgG positive sera, 57 anti-CHIKV IgM positive sera and 163 anti-CHIKV IgG/IgM negative sera which were confirmed by commercial enzyme-linked immunosorbent assays (ELISAs) (Inbios CHIKjj Detect™ IgM Capture ELISA, Inbios CHIKjj Detect™ IgG ELISA (InBios International Inc., Seattle, WA, USA), Anti-CHIKV ELISA (IgM), Anti- CHIKV ELISA (IgG) (Euroimmun, Lübeck, Germany)). The ichroma detected all 36 anti-CHIKV IgG and 57 anti-CHIKV IgM positivity (100% sensitivity). For 163 anti-CHIKV IgG/IgM negative sera, the ichroma showed one false positive for IgM (99.4% specificity). The ichroma showed no cross-reactivity and no interference. The ichroma demonstrated good diagnostic performance compared to the current ELISAs.

Delayed NK Cell Reconstitution and Reduced NK Activity Increased the Risks of CMV Disease in Allogeneic-Hematopoietic Stem Cell Transplantation.

Cytomegalovirus (CMV) infection has a significant impact in patients after allogeneic hematopoietic stem cell transplantation (HSCT). We investigated natural killer (NK) cell reconstitution and cytotoxic/cytokine production in controlling CMV infection, especially severe CMV disease in HSCT patients. Fifty-eight patients with acute myeloid leukemia (AML) who received allo-HSCT were included. We monitored NK reconstitution and NK function at baseline, 30, 60, 90, 120, 150, and 180 days after HSCT, and compared the results in recipients stratified on post-HSCT CMV reactivation (n = 23), non-reactivation (n = 24) versus CMV disease (n = 11) groups. The CMV disease group had a significantly delayed recovery of CD56dim NK cells and expansion of FcRγ-CD3ζ+NK cells started post-HSCT 150 days. Sequential results of NK cytotoxicity, NK cell-mediated antibody-dependent cellular cytotoxicity (NK-ADCC), and NK-Interferon-gamma (NK-IFNγ) production for 180 days demonstrated delayed recovery and decreased levels in the CMV disease group compared with the other groups. The results within 1 month after CMV viremia also showed a significant decrease in NK function in the CMV disease group compared to the CMV reactivation group. It suggests that NK cells' maturation and cytotoxic/IFNγ production contributes to CMV protection, thereby revealing the NK phenotype and functional NK monitoring as a biomarker for CMV risk prediction, especially CMV disease.

Heterochiral Assembly of Amphiphilic Peptides Inside the Mitochondria for Supramolecular Cancer Therapeutics.

Self-assembly of peptides containing both l- and d-isomers often results in nanostructures with enhanced properties compared to their enantiomeric analogues, such as faster kinetics of formation, higher mechanical strength, and enzymatic stability. However, occurrence and consequences of the heterochiral assembly in the cellular microenvironment are unknown. In this study, we monitored heterochiral assembly of amphiphilic peptides inside the cell, specifically mitochondria of cancer cells, resulting in nanostructures with refined morphological and biological properties owing to the superior interaction between the backbones of opposite chirality. We have designed a mitochondria penetrating tripeptide containing a diphenyl alanine building unit, named as Mito-FF due to their mitochondria targeting ability. The short peptide amphiphile, Mito-FF co-assembled with its mirror pair, Mito-ff, induced superfibrils of around 100 nm in diameter and 0.5-1 µm in length, while enantiomers formed only narrow fibers of 10 nm in diameter. The co-administration of Mito-FF and Mito-ff in the cell induced drastic mitochondrial disruption both in vitro and in vivo. The experimental and theoretical analyses revealed that pyrene capping played a major role in inducing superfibril morphology upon the co-assembly of racemic peptides. This work shows the impact of chirality control over the peptide self-assembly inside the biological system, thus showing a potent strategy for fabricating promising peptide biomaterials by considering chirality as a design modality.

Synthesis and Feasibility Evaluation of a new Trastuzumab Conjugate Integrated with Paclitaxel and 89Zr for Theranostic Application Against HER2-Expressing Breast Cancers.

The preparation and in  vitro evaluation of a theranostic conjugate composed of trastuzumab, paclitaxel (PTX), and deferoxamine (DFO)-chelated 89Zr have been reported. These comounds have potential applications against HER2 receptor positive breast cancers. We conjugated DFO and PTX to trastuzumab by exploiting simple conjugation chemistry. The conjugate (DFO-trastuzumab-PTX) showed excellent radiolabeling efficiency with 89Zr and the labeled conjugate had high in vitro stability in human serum. Furthermore, DFO-trastuzumab-PTX displayed comparable cytotoxicity with PTX and 89Zr-DFO-trastuzumab-PTX exhibited HER2 receptor-mediated binding on HER2-positive MDA-MB-231 breast cancer cells. The results of our in vitro study indicate high potential of 89Zr-DFO-trastuzumab-PTX to be utilized in the theranostic application against HER2-postive breast cancers.

Targeted tumor detection: guidelines for developing biotinylated diagnostics.

The challenge in achieving precision medicine relies on how to advance and/or enhance new as well as old therapeutic strategies. Here, we highlight the significant role hydrophilicity of biotinylated fluorescent probe's plays on their cellular uptake behaviour.

Indomethacin-guided cancer selective prodrug conjugate activated by histone deacetylase and tumour-associated protease.

An indomethacin-guided drug delivery conjugate (IGDDC) has been designed by utilizing cancer associated elevated HDAC and CTSL activities as consecutive demasking ventures for drug activation. IGDDC exhibited preferential uptake by COX-2 positive cells both in vitro and ex vivo highlighting indomethacin's role in designing new cancer-specific drug delivery frameworks.

BODIPY/Nile-Red-Based Efficient FRET Pair: Selective Assay of Endoplasmic Reticulum Membrane Fluidity.

We synthesized a boron-dipyrromethene (BODIPY)/Nile Red hybrid probe capable of selectively recognizing fluidity changes in the endoplasmic reticulum (ER) membrane due to its preferential localization to the ER and strong energy transfer from BODIPY to the Nile Red moiety, emitting only in nonaqueous environments. ER membrane fluidity in HepG2 cells was markedly reduced by a cell model of metabolic syndrome.

An intramolecular crossed-benzoin reaction based KCN fluorescent probe in aqueous and biological environments.

A turn-on fluorescent probe was designed for selective cyanide anion sensing in aqueous and biological environments. The probe underwent an intramolecular crossed-benzoin reaction in the presence of KCN to expel the fluorophore resorufin. This probe was sensitive to KCN concentrations as low as 4 nM in aqueous media.

Chemical sensing of neurotransmitters.

In the past few decades, the development of chemosensors for neurotransmitters has emerged as a research area of significant importance, which attracted a tremendous amount of attention due to its high sensitivity and rapid response. This current review focuses on various neurotransmitter detection based on fluorescent or colorimetric spectrophotometry published for the last 12 years, covering biogenic amines (dopamine, epinephrine, norepinephrine, serotonin, histamine and acetylcholine), amino acids (glutamate, aspartate, GABA, glycine and tyrosine), and adenosine.

Cu(2+)-responsive bimodal (optical/MRI) contrast agent for cellular imaging.

A water-soluble T1 magnetic resonance imaging contrast agent (1) has been synthesized. The bimodal contrast agent 1 responds to the Cu(2+) ion in living cells by enhancing the MRI modality signal whereas the optical signal gradually drops. This dual modality probe response depends on the cellular free copper ions in RAW 264.7 cells even at the micromolar level.

Failed anterior lumbar interbody fusion due to incomplete foraminal decompression.

BACKGROUND: Anterior lumbar interbody fusion (ALIF) has gained widespread popularity for spinal disorders requiring fusion. The purpose of this study was to analyze ALIF failures. METHODS: The medical records of 223 patients treated with ALIF between January 2007 and June 2008 were retrospectively reviewed. Patients with unfavorable outcomes, including subsequent posterior decompression at the index level or poor outcomes after ALIF were identified based on clinical and radiological findings. The patients were divided into two groups: an unfavorable group and a favorable group. Preoperative clinical and radiological factors for each group were statistically analyzed. RESULTS: Two hundred of the 223 patients were enrolled in this study. Thirteen (6.5%) of 200 patients resulted in unfavorable outcome. Four patients (2%) of them underwent posterior decompressive surgery. The main cause of unfavorable outcomes was incomplete decompression of the foraminal stenosis. Unfavorable outcomes were obtained in patients with the level of L5-S1 (p = 0.036), higher body mass index (p = 0.048), higher percentage of slippage (p = 0.024), and severe facet arthropathy (p = 0.013). However, there was no difference in preoperative disc height, foraminal size, facet angle, facet tropism, or preoperative visual analog scale for back and leg pain, the Oswestry disability index, symptom duration, and fusion rate between the two groups. CONCLUSION: Based on these results, posterior decompression and fusion may be considered for obese patients with the level of L5-S1, high-grade spondylolisthesis, or severe facet arthropathy. On the other hand, ALIF can be used an effective alternative treatment in many spinal disorders requiring fusion.

Proton-conductive nanochannel membrane for fuel-cell applications.

Novel design of proton conductive membrane for direct methanol fuel cells is based on proton conductivity of nanochannels, which is acquired due to the electric double layer overlap. Proton conductivity and methanol permeability of an array of nanochannels were studied. Anodic aluminum oxide with pore diameter of 20 nm was used as nanochannel matrix. Channel surfaces of an AAO template were functionalized with sulfonic groups to increase proton conductivity of nanochannels. This was done in two steps; at first -SH groups were attached to walls of nanochannels using (3-Mercaptopropyl)-trimethyloxysilane and then they were converted to -SO3H groups using hydrogen peroxide. Treatment steps were analyzed by Fourier Transform Infrared spectroscopy and X-ray Photoelectron Spectroscopy. Proton conductivity and methanol permeability were measured. The data show methanol permeability of membrane to be an order of magnitude lower, than that measured of Nafion. Ion conductivity of functionalized AAO membrane was measured by an impedance analyzer at frequencies ranging from 1 Hz to 100 kHz and voltage 50 mV to be 0.15 Scm(-1). Measured ion conductivity of Nafion membrane was 0.05 Scm(-1). Obtained data show better results in comparison with commonly used commercial available proton conductive membrane Nafion, thus making nanochannel membrane very promising for use in fuel cell applications.

Rapid cell-deformability sensing system based on slit-flow laser diffractometry with decreasing pressure differential.

A slit-flow apparatus with a laser-diffraction method has been developed with significant advances in ektacytometry design, operation and data analysis. In the slit-flow ektacytometry, the deformation of red blood cells subjected to continuously decreasing shear stress in slit-flow can be quickly measured with adopting a laser-diffraction technique. Both the laser-diffraction image and pressure were measured with respect to time, which enable to determine the elongation index (EI) and the shear stress. The range of shear stress is 0-35 Pa and the measuring time is < 2 min. The EI is determined from an isointensity curve in the diffraction pattern using an ellipse-fitting program. The present study proposed the deformability index (DI) as a new measure of the RBC deformability, which is defined as an integral area under the EI curve between 0 and tau10 (tau(w) = 0-10). The key advantage of this design is the incorporation of a disposable element that holds the blood sample, which enables the present system to be easily used in a clinical setting.