Fluorescent Spots Research Articles

Curcumin nanoparticles: Neuroprotection in Alzheimer's disease assessed through the eye

Aims/Purpose: Alzheimer's disease (AD) is the most prevalent form of dementia and remains a pressing concern in our society with an ageing population. Increasing evidences suggest a link between brain damage and retinal ganglion cell (RGC) loss opening new paradigm to diagnose this condition using the eye as a window to the brain. Curcumin is a natural polyphenol with neuroprotective properties but a low bioavailability preventing its use as a potential treatment in AD. The goal of this research was to assess a novel formulation of curcumin in a triple transgenic Alzheimer's disease (3xTg‐AD) mouse model and to demonstrate a correlation between Aβ/pTau brain deposition and RGC loss.Methods: 10‐month‐old 3xTg‐AD mice were treated for 3 months with either 0.38 mg/kg intranasal curcumin nanoparticles (CNs) (n = 7) or the equivalent vehicle (n = 6). After 3 months of treatment, animals were imaged using Detection of Apoptosing Retinal Cells (DARC). DARC count was defined as the number of fluorescent spots counted by a masked investigator. After sacrifice, their brains were harvested and immunostained for amyloid‐beta (Aβ) and phosphorylated tau (pTau). Retinas were immunostained with Brn3a, a retinal ganglion cell (RGC) marker. Then, RGC regularity index (RI) was calculated because it is more sensitive than RGC density and declining values of RI are observed during RGC loss and correlate with disease severity.Results: In the brain, CNs were able to reduce Aβ deposition (2.9 ± 0.3 vs 4.4 ± 0.4 Aβ score, p < 0.05) and pTau deposition (1.9 ± 0.7 vs 6.3 ± 1.5 pTau deposition, p < 0.05) compared to the equivalent vehicle. DARC count was reduced with CN treatment compared to vehicle (17.4 ± 3.3 vs 49.1 ± 13.3 DARC spots, p < 0.05). More importantly, CN treatment increased significantly RGC RI compared to vehicle (1.73 ± 0.04 vs 1.58 ± 0.04, p < 0.05) suggesting a neuroprotective effect by reducing RGC loss. Interestingly, DARC count correlated with RGC RI (correlation coefficient ‐0.452, p < 0.05) and Aβ deposition in the brain (correlation coefficient 0.509, p < 0.05).Conclusions: CNs are neuroprotective by reducing Aβ and pTau deposition in the brain and RGC loss. More importantly, DARC can be used to monitor disease activity as it correlates with RGC loss and Aβ deposition in the brain. Further studies are needed to confirm these results.

Total Phenolic, Flavonoid Contents, and Antioxidant Activities of Different Parts of Malus domestica L. in Iraq

The current study was designed to estimate the qualitative and quantitative analyses of total phenolic and flavonoid compounds extracted by two different techniques (maceration and soxhlet) for three aerial parts (leaves, stems, and petioles) of Malus domestica grown naturally in Iraq. A general phytochemical investigation of the three parts of the plant had been carried out before the extraction process. Qualitative estimation was held through the Thin Layer Chromatographic Technique to visualize separated fluorescent spots as proposed phenolic and flavonoid compounds corresponding to standard compounds. Total Phenolic Content (TPC) and Total Flavonoid Content (TFC) were determined by colorimetric methods and by HPLC method. The free radical scavenging assay for (DPPH) was carried out to measure antioxidant activity for all extracted portions. Phytochemical screening of the three parts of Malus domestica showed the presence of different active constituents such as saponins, tannins, alkaloids, terpenoids, flavonoids, polyphenols, and glycosides. The maceration extraction technique resulted in a higher yield for all fractions compared to the Soxhlet technique. The results also showed a variation in the phenolic compounds among the different parts, revealing that the leaves of Malus domestica had a high content of phenolic acids and flavonoids compared to the other parts, while the petioles (extracted by soxhlet) showed the strongest antioxidant activity (86.01 %) compared to other parts. Based on HPLC assay, the components obtained from leaves, stems, and petioles ethanolic extract were declared to contain 7 phenolic acids (including ascorbic acid, gallic acid, vanillic acid, chlorogenic acid, p-coumaric acid, caffic acid, and ferulic acid). Whereas, 10 flavonoids (including rutin, quercetin, myricetin, catechin, kaempferol, hispartin, isorhamnetin, apigenin,coumarin and luteolin) were identified.

Deep learning method for detecting fluorescence spots in cancer diagnostics via fluorescence in situ hybridization

Fluorescence in Situ Hybridization (FISH) is a technique for macromolecule identification that utilizes the complementarity of DNA or DNA/RNA double strands. Probes, crafted from selected DNA strands tagged with fluorophore-coupled nucleotides, hybridize to complementary sequences within the cells and tissues under examination. These are subsequently visualized through fluorescence microscopy or imaging systems. However, the vast number of cells and disorganized nucleic acid sequences in FISH images present significant challenges. The manual processing and analysis of these images are not only time-consuming but also prone to human error due to visual fatigue. To overcome these challenges, we propose the integration of medical imaging with deep learning to develop an automated detection system for FISH images. This system features an algorithm capable of quickly detecting fluorescent spots and capturing their coordinates, which is crucial for evaluating cellular characteristics in cancer diagnosis. Traditional models struggle with the small size, low resolution, and noise prevalent in fluorescent points, leading to significant performance declines. This paper offers a detailed examination of these issues, providing insights into why traditional models falter. Comparative tests between the YOLO series models and our proposed method affirm the superior accuracy of our approach in identifying fluorescent dots in FISH images.

Mapping Endocytic Vesicular Acidification with a pH-Responsive DNA Nanomachine.

Mapping the endocytic vesicular acidification process is of prior importance to better understand the health and pathological processes of cells. Herein, by integrating a pH-sensitive i-motif and a pair of fluorescence resonance energy transfer (FRET) into a tetrahedral DNA framework (TDF), we develop a pH-responsive DNA nanomachine, allowing for efficient sensing of pH from 7.0 to 5.5 via the pH-triggered spatial proximity modulation of FRET. The inheriting endo-lysosome-targeting ability of TDF enables spatiotemporal tracking of endocytic vesicle acidification during the endosomal maturation process. Analysis of pH-dependent FRET response at single fluorescent spot level reveals the significant difference of endocytic vesicular acidification between normal and cancer cells. The performance of pH-responsive DNA nanomachine underlines its potential for studies on vesicle acidification-related pathologies as a universal platform.

Direct measurement of multi-angle evanescent field by whispering gallery mode of the microsphere and fluorescent spots in an optical waveguide fluorescence microscopy

Evanescent field (EF) has been widely applied in various micro-imaging techniques for its ability to excite surfaces. However, measuring the multi-angle EF remains challenging. In this paper, the whispering gallery mode (WGM) is observed in an excited microsphere on an optical waveguide (OWG) with a thickness of 0.6 mm, which is used to determine the diameter of the excited microsphere. A simple and nondestructive measurement method for multi-angle OWG-EF is proposed, which is based on the reliable diameter of the microsphere, determined by WGM and the TIRF spots. The measurement result for multi-angle OWG-EF shows a dynamic range between ∼180 and ∼2400 nm, which shows good agreement with the simulation results. The method synchronization possible for EF measurements and fluorescent experiments.

Polarization-modulated dual-wavelength metalens to overcome the diffraction limit

Two-photon stimulated emission depletion (STED) fluorescence microscopy has demonstrated advantages in ultrahigh resolution biological imaging. However, the bulky setup for generating excitation and depletion beams hinders the system development. Here, a miniaturized single-layer polarization-modulated dual-wavelength metalens is proposed for applications in STED. The metalens can achieve achromatic focusing at 532 nm and 632 nm, and can generate both a Gaussian-shaped spot and a donut-shaped depletion spot across different polarization states. Based on the theoretical analysis, we obtained an effective fluorescence spot that overcomes the diffraction limit. The multifunctional imaging capability of the metalens is also demonstrated, including bright-field and edge-detection imaging. The proposed metalens offers several advantages such as flexibility, single-layer, light-weight and multifunctionality. These features make it an ideal candidate for enabling super-resolution in minimally invasive imaging.

Synthetic Chemistry and Microelectrode Arrays for Point of Care Diagnostics

Molecular diagnostics typically require a molecular interaction that identifies a specific target, a device that detects, quantifies, and records that interaction, and an interface between those two elements. Each feature is critical for the success of the device. Yet while the first two are matters of intense interest an research, the surface itself is often ignored. This is problematic because it provides the platform for the whole "experiment". For a "point-of-care" diagnostic, the surface on the device must be stable both in terms of chemistry and time while still allowing the signal from the molecular interaction to be sensed and recorded.With this in mind, we have been focusing on the use of diblock copolymers as molecular surfaces for the construction of "point-of-care" diagnostics. We have developed a toolbox of chemical reactions that can be used site-selectively on such surfaces, and we have recently demonstrated that the approach taken is compatible with the use of DNA-aptamers to do multiplex sensing on a high density microelectrode array using a surface that is stable for a year. We have also illustrated how the quality of the signaling study conducted on an array is dependent on optimization of the chemical reaction.But exactly how good are the chemical reactions employed on the arrays to build a surface in a site-selective manner? One can tell with the use of fluorescence based studies that reactions happen where you want then to happen, but are there background reactions that can be problematic for a multiplex sensing experiment, do the reactions happen in high yield, and how much of an expensive, difficult to obtain biological reagent might be lost due to the confinement strategy? Are some reactions better than others in this regard? In short, if we are to optimize the surfaces constructed on a diagnostic device, then we need not only have tools in place for conducting synthetic chemistry on the device, but also the tools in place necessary to analyze those reactions. Understanding the chemistry that can and/or does occur at any electrode in a high density array requires more than looking at pretty pictures of fluorescent spots. In the talk to be given, we will utilize a combination of a "Kenner-safety-catch" linker strategy and molecular biology techniques to answer key questions about the synthetic chemistry used to construct the DNA-aptamer based multiplex sensor mentioned above.

(Invited) Comprehensive Analysis of Exciton Diffusion with Time-Resolved Fluorescence Spectroscopy, Anisotropy and Imaging

Excitons produced in materials play a crucial role in photo-energy conversion such as photovoltaics and electroluminescence devices. The temporal and spatial diffusion of excitons is a key factor for dominating the fundamental performance of optoelectronic materials. In this context, analysis of the exciton diffusion dynamics is an important issue for obtaining the rational design of the materials. Excitons diffusing in materials can be characterized by several parameters such as the energy level, orientation of the transition dipole moment and spatial distribution, and the detection of these properties is required for the comprehensive analysis. In the present study, we show time-resolved fluorescence methods for detecting the above relevant properties of excitons.First, time-resolved fluorescence spectroscopy is a basic technique for analyzing the exciton diffusion dynamics. Fluorescence intensity is detected as functions of observation wavelength and time, and the spectral intensity and shift of fluorescence bands provide information on the population of excitons and their energy level. For example, dynamic Stokes shift indicates downhill energy migration and excitons are trapped by the defective site in molecular aggregates. Second, fluorescence anisotropy can be a good indicator for tracking the exciton diffusion in amorphous materials. Fluorescence anisotropy is sensitive to orientation change in transition dipole moments (TDMs) between absorption and fluorescence. In systems where the relative orientation of adjacent molecules is different from each other, such as amorphous solids, the exciton diffusion is accompanied with the change in TDM. Thus, appropriate modeling of molecular alignment enables quantitative estimation of the exciton diffusion coefficient and diffusion length from the anisotropy signal. Finally, time-resolved imaging is a combination of time-resolved spectroscopy and super-resolution microscopy, and an emergent technique for visualizing real-space propagation of excitons in materials. The diffraction-limited excitation beam produces excitons in several hundreds of nanometers and the subsequent exciton diffusion is evaluated by the spatial width of the fluorescence spot. The temporal broadening of the fluorescence spot directly reflects the exciton distribution and we can intuitively obtain the diffusion coefficient and length. Unlike the conventional methods for bulk materials, the advantage of the time-resolved imaging is the applicability to materials with nano- and meso-scale heterogeneous structure and it enables site-selective evaluation of the exciton transport capability. In the conference site, we will also show the application of the above methods to supramolecular polymers and thermally activated delayed fluorescence materials. Figure 1

Autophagy promotes replication of Bombyx mori Nucleopolyhedrovirus in insect cells

BmNPV is a pathogen that infects silkworms exclusively. Although the interaction between BmNPV and the silkworm has been widely noticed and studied, its specific mechanism has still not been elucidated. In this study, we investigated whether BmNPV infection induces the onset of host cell autophagy to enhance viral replication. We observed a significant increase in double- or single-membrane vesicles and an accumulation of enhanced green fluorescent protein eGFP-ATG8 spots in virus-infected cells 72 h after BmNPV infection, accompanied by a conversion of ATG8 to ATG8-PE. In addition, we observed changes in the mitochondrial morphology of BmN cells after BmNPV infection by transmission electron microscopy. By detecting the mitochondrial membrane potential, we found that BmNPV infection resulted in the decrease of mitochondrial membrane potential, and that eGFP-ATG8 was able to co-localise with mitochondria after virus infection of the cells. Moreover, the use of drugs to regulate the occurrence of autophagy affects the replication of cellular BmNPV. Our data demonstrates that BmNPV infection induces host cell autophagy and leads to cellular mitochondrial damage, which in turn may lead to mitochondrial autophagy, and that BmNPV-induced host autophagy promotes its replication in cells. These findings will provide clues for further understanding of host-virus interactions.

Evaluation of Fluorescent Spot Test with Dried Blood Spots for Glucose-6-Phosphate Dehydrogenase Deficiency Screening in A Malaria-Endemic Area

The utilization of dried blood spot (DBS) samples for screening glucose-6-phosphate dehydrogenase (G6PD) deficiency remains limited in resource-constrained and malaria-endemic regions of Thailand. This study evaluated the feasibility of employing DBS for G6PD deficiency screening among 242 participants (118 males and 124 females) who provided fresh whole blood (FWB) and DBS samples for analysis. The G6PD deficiency diagnostic performances of the fluorescent spot test using DBS (FST-DBS) were compared to those using FWB (FST-FWB). The G6PD gene variant was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using DBS samples. The FST-DBS showed no significant difference in sensitivity (95.0% vs 100.0%) but superior specificity (100.0% vs 80.2%) and a positive predictive value (100.0% vs. 50.0%) compared to FST-FWB. The PCR-RFLP revealed a G6PD mutation incidence rate of 16.5% (11.1% in males and 5.4% in females). Among 40 DBS samples, 39 (97.5%) were the Mahidol (487G>A) while a sample (2.5%) which both FST-DBS and FST-FWB showed positive results had an unidentified variant. Therefore, FST-DBS is an alternative format for G6PD deficiency screening in malaria-endemic regions, particularly where resources are limited.

Isolation of Aspergillus sp from some Decomposing Fruits and Vegetables from Banana Rhyzosphere Soil for Citric Acid Production

Aims: The general objective of this study is to isolate certain strains capable of producing citric acid. Place and Duration of Study: Sample collection was carried out on two types of organic matter. Sampling was done from February to April 2021 in 3 municipalities in Abidjan with 10 samples per site. Methodology: To carry out this work, isolation and purification of Aspergillus sp strains were carried out. Macroscopic and microscopic identifications of the mold isolates were carried out. The search for aflatoxin-producing molds was carried out. The analysis ended with a screening of molds capable of synthesizing citric acid. Results: Aspergillus niger, Aspergillus sp1 and Aspergillus sp2 showed no fluorescence, while Aspergillus flavus, Aspergillus candidus and Aspergillus fumigatus showed fluorescent spots, indicating the presence of aflatoxin. Conclusion: Aspergillus isolates capable of producing citric acid were isolated during this study. Aspergillus niger, Aspergillus sp1 and Aspergillus sp2 do not produce aflatoxin and have the capacity to synthesize citric acid.

Abstract 5866: TESC mediates resistance to lenvatinib in hepatocellular carcinoma by regulating cell autophagy

Abstract Objective: To investigate the mechanism by which TESC (Tescalcin) induces lenvatinib resistance in hepatocellular carcinoma (HCC) through autophagy mediation. Methods:1) Utilized established liver cancer organoids from over 70 patients for lenvatinib drug sensitivity screening and transcriptome sequencing to identify lenvatinib-resistant genes. 2) Constructed stable TESC overexpression and downregulation liver cancer cell lines. Employed CCK8 assays to plot IC50 drug sensitivity curves, elucidating changes in lenvatinib sensitivity in liver cancer cells after TESC overexpression or downregulation. 3) Used TESC-stable cells to establish subcutaneous tumor models and intrahepatic tumor models in nude mice. After tumor formation, administered lenvatinib orally to observe whether TESC affects liver cancer sensitivity to lenvatinib in vivo. 4) Conducted Western blot (WB) analysis to assess the expression of autophagy-related molecules (LC3B II/I, P62, and Beclin1 proteins) in TESC downregulated or overexpressed stable cell lines and their control cell lines. Utilized the LC3-GFP-mRFP fluorescence dual-labeling lentivirus system and laser confocal microscopy to examine autophagic flux. 5)Treated TESC downregulated cells with the autophagy inhibitor 3-MA. Conducted WB to assess the expression levels of autophagy-related proteins and plotted drug sensitivity curves using IC50 experiments to evaluate the impact of 3-MA on reversing liver cancer cell sensitivity to lenvatinib. Results: Compared to the control group, HCC cells overexpressing TESC showed an increased IC50 value and reduced sensitivity to lenvatinib, while TESC downregulation resulted in a decreased IC50 value and decreased sensitivity to lenvatinib. Subcutaneous tumor experiments in nude mice indicated that, compared to the control group, tumors with reduced TESC expression were more sensitive to lenvatinib. Additionally, in HCC cells overexpressing TESC, protein expression levels of LC3B II/I and Beclin1 significantly decreased, while P62 expression increased. Conversely, TESC downregulation significantly increased protein expression levels of LC3B II/I and Beclin1, while P62 expression decreased. Furthermore, results from the LC3-GFP-mRFP autophagy dual-labeling lentivirus system showed a significant reduction in fluorescence spots in the TESC overexpression group compared to the control group, indicating weakened autophagic flux. Treatment of TESC downregulated liver cancer cells with 3-MA resulted in an increased IC50 value compared to the control group. Conclusion: TESC expression levels are associated with the sensitivity of liver cancer cells to lenvatinib, possibly by inhibiting autophagy and affecting the sensitivity of liver cancer cells to lenvatinib. Citation Format: Hao Zhuang, Tingting Zhang, Jiaqi Chen. TESC mediates resistance to lenvatinib in hepatocellular carcinoma by regulating cell autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5866.

Single-Molecule Catalysis in the Palladium Cross-Coupling Reaction Cycle.

Single-molecule (SM) methods are applied to study various types of catalytic processes in chemical and biochemical reactions. In this study, the Suzuki-Miyaura cross-coupling reaction forming a fluorescent product is investigated within the SM approximation. Stochastic analysis of emission intermittency in selected nanoscopic spots allows us to determine the single-molecule turnover frequency (SM-TOF) of the Pd catalyst in a specific probe reaction. We generate and analyze simulated intermittency time traces of a single catalyst surrounded by reactant molecules to assess the reliability of the method applied to real intermittency time trace data from hundreds of nanoscopic fluorescence spots. The results demonstrate that the proposed method can be used to evaluate the average SM-TOF of Pd in a cross-coupling reaction.

A novel multicolor fluorescent spot assay for the functional assessment of chimeric antigen receptor (CAR) T-cell products

Background aimsChimeric antigen receptor (CAR) T-cell (CAR-T) therapies have revolutionized the treatment of B-cell lymphomas. Unfortunately, relapses after CD19-targeted CAR-T are relatively common and, therefore, there is a critical need for assays able to assess the function and potency of CAR-T products pre-infusion, which will hopefully help to optimize CAR-T therapies. We developed a novel multicolor fluorescent spot assay (MFSA) for the functional assessment of CAR-T products on a single-cell level, combining the numerical assessment of CAR-T products with their functional characterization. MethodsWe first used a standard single-cell interferon (IFN)-γ enzyme-linked immune absorbent spot assay to measure CD19-targeted CAR-T responses to CD19-coated beads. We then developed, optimized and validated an MFSA that simultaneously measures the secretion of combinations of different cytokines on a single CAR-T level. ResultsWe identified IFN-γ/tumor necrosis factor-α/granzyme B as the most relevant cytokine combination, and we used our novel MFSA to functionally and numerically characterize two clinical-grade CAR-T products. ConclusionsIn conclusion, we have developed a novel assay for the quantitative and functional potency assessment of CAR-T products. Our optimized MFSA is cost-effective, easy to perform, reliable, can be performed overnight, allowing for a fast delivery of the product to the patient, and requires relatively minimal maintenance and training. The clinical value of our novel assay will be assessed in studies correlating the pre-infusion assessment of CAR-T products with the patients’ outcome in a prospective fashion.

Phomopsterone B Alleviates Liver Fibrosis through mTOR-Mediated Autophagy and Apoptosis Pathway.

Liver fibrosis is the initial pathological process of many chronic liver diseases. Targeting hepatic stellate cell (HSC) activation is an available strategy for the therapy of liver fibrosis. We aimed to explore the anti-liver fibrosis activity and potential mechanism of phomopsterone B (PB) in human HSCs. The results showed that PB effectively attenuated the proliferation of TGF-β1-stimulated LX-2 cells in a concentration-dependent manner at doses of 1, 2, and 4 μM. Quantitative real-time PCR and Western blot assays displayed that PB significantly reduced the expression levels of α-SMA and collagen I/III. AO/EB and Hoechst33342 staining and flow cytometry assays exhibited that PB promoted the cells' apoptosis. Meanwhile, PB diminished the number of autophagic vesicles and vacuolated structures, and the LC3B fluorescent spots indicated that PB could effectively inhibit the accretion of autophagosomes in LX-2 cells. Moreover, rapamycin and MHY1485 were utilized to further investigate the effect of mTOR in autophagy and apoptosis. The results demonstrated that PB regulated autophagy and apoptosis via the mTOR-dependent pathway in LX-2 cells. In summary, this is the first evidence that PB effectively alleviates liver fibrosis in TGF-β1-stimulated LX-2 cells, and PB may be a promising candidate for the prevention of liver fibrosis.

Self-assembled bamboo-like carbon nanotubes based on chiral H8BINOL sensors to recognize cinchonidine efficiently by diastereoisomer complexes.

Fluorescence recognition for the antimalarial cinchonidine could be achieved efficiently and rapidly through bamboo-like carbon nanotubes based on chiral conjugated H8BINOL derivatives. Herein, it was proved that the chiral fluorescence probe H8BINOL exhibited excellent fluorescence identification ability for cinchonidine. The structure and size of the S-1 (S-(3,3'-phenyl)-5,5'6,6',7',8,8'-octahydro-[1,1'-dinaphthalene]-2,2'-diol) and R-1 (R-(3,3'-phenyl)-5,5'6,6',7',8,8'-octahydro-[1,1'-dinaphthalene]-2,2'-diol) were studied by using the DLS, TEM, and SEM spectra, which exhibited a self-assembled bamboo-like carbon nanotube structure. In the CD (circular dichroism) test, cinchonidine was added to a pair of enantiomers of H8BINOL derivatives. The different configurations of H8BINOL derivatives showed significantly different Cotton effects for cinchonidine, indicating that cinchonidine formed diastereoisomer π-π complexes with different configurations of H8BINOL derivatives. From the AFM tests, it was revealed that cinchonidine could effectively quench the fluorescent spot of the probes quickly. The fluorescence titration tests demonstrated that 6.4 × 10-7 mol of cinchonidine could completely quench the fluorescence sensor of S-1 (2 × 10-5 M, 2 mL) through the formation of a 1 : 1 complex. The limit of detection (LOD) of S-1 was calculated to be 6.08 × 10-10, which indicates that S-1 has a high sensitivity and can be applied effectively to the practice of identifying cinchonidine. Meanwhile, the fluorescence sensor R-1 also exhibited the same sensibility with a low limit of detection (7.60 × 10-10).

Prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency among the fulminant hepatitis A virus infection patients.

Hepatitis A is a widespread viral infection with significant public health implications. Assessing glucose 6-phosphate dehydrogenase (G6PD) deficiency in hepatitis A patients is essential for various reasons, including prognosis, disease severity evaluation, encephalopathy risk identification, tailored management, and advancing scientific understanding. This study aimed to investigate the prevalence and clinical implications of G6PD impairment in individuals with fulminant hepatitis A. A cross-sectional descriptive analysis was conducted, involving hospitalized patients with fulminant hepatitis A. Demographic data, prevalence rates, and clinical findings were recorded in a database. The diagnosis of hepatitis A infection was confirmed using an anti-HAV IgM antibody test, and G6PD enzyme activity was measured with a fluorescent spot assay. Out of 81 patients with hepatitis A, 57 (70.4%) were males, and 24 (29.5%) were females, with an average age of 24.6 years. Dark yellow urine and anorexia were the most common clinical symptoms. Notably, 30 (37%) patients lacked G6PD. The group with G6PD deficiency showed significantly higher rates of encephalopathy and mortality (P<0.01), along with elevated bilirubin (P=0.00), abnormal coagulation parameters, and low hemoglobin levels (P=0.00). In light of these findings, the present study proposes the implementation of routine G6PD level assessments and the evaluation of other relevant markers in regions where hepatitis A is endemic. Furthermore, the study underscores the need for vigilant monitoring of hemolysis and encephalopathy in affected patients to optimize clinical management and reduce morbidity and mortality associated with this condition.

Dual-Signal Imaging Mode Based on Fluorescence and Electrochemiluminescence for Ultrasensitive Visualization of SARS-CoV-2 Spike Protein.

Accurate and reliable detection of SARS-CoV-2 is critical for the effective prevention and rapid containment of COVID-19. Current approaches suffer from complex procedures or a single signal readout, resulting in an increased risk of false negatives and low sensitivity. Here, we developed a fluorescence (FL) and electrochemiluminescence (ECL) dual-mode imaging platform based on a self-powered DNAzyme walker to achieve accurate surveillance of SARS-CoV-2 spike protein at the single-molecule level. The specific activation of the DNAzyme walker by the target protein provides the power for the system's continuous running, enabling the simultaneous recording of the reduction in fluorescence spots and the appearance of ECL spots generated by the Ru-doped metal-organic framework (MOF) emitter. Therefore, the constructed imaging platform can achieve dual-mode detection of spike protein via reverse dual-signal feedback, which could effectively eliminate false-positive or false-negative signals and improve the detection accuracy and sensitivity with a low detection limit. In particular, the dual-mode accuracy of spike protein diagnosis in samples has been significantly improved compared to single-signal output means. In addition, this dual-mode imaging platform may become a prospective diagnostic device for other infectious viruses.

Feasibility Study for Longitudinal Retinal Imaging in the Anti‐Amyloid Treatment in Asymptomatic Alzheimer’s Disease (A4) Trial

AbstractBackgroundAlterations to the retina manifest in patients diagnosed with neurodegenerative diseases such as Alzheimer’s disease (AD). Retinal imaging techniques open the possibility for non‐invasive evaluation of AD pathology. Clinically AD diagnosed patients exhibit retinal spots that may be amyloid deposits. Few studies monitoring preclinical individuals exist, limiting the assessment of the feasibility of retinal imaging as a biomarker for early‐stage AD risk detection.MethodWe compared extent and distribution of retinal fluorescent spots and cerebral amyloid in clinically normal individuals who screened positive for high amyloid levels through positron emission tomography (PET) from the Anti‐Amyloid Treatment in Asymptomatic Alzheimer Disease (A4) as well as a companion cohort of individuals who exhibited low levels of amyloid PET in the Longitudinal Evaluation of Amyloid Risk and Neurodegeneration (LEARN) study. We quantified the number of curcumin‐positive fluorescent retinal spots from participants from both studies to determine retinal amyloid deposition at baseline.ResultParticipants from the A4 trial exhibited a greater number of retinal spots compared to those from the LEARN study. We report a positive correlation between retinal spots and brain amyloid, as measured by the standardized uptake value ratio (SUVr).ConclusionThe results of this study support the use of retinal fundus imaging for and assessing relationships with brain amyloid PET SUVr. Further work is needed to determine the nature of retinal spots and their relationship with actual amyloid plaques cross‐sectionally and longitudinally.

Modularity impacts cellulose surface oxidation by a lytic polysaccharide monooxygenase from Streptomyces coelicolor

AbstractLytic polysaccharide monooxygenases (LPMOs) catalyze the oxidation of β-(1,4)-linked polysaccharides, such as cellulose, in a reaction that requires an electron donor and H2O2 as co-substrate. Several LPMOs include a carbohydrate-binding module (CBM), which promotes action on insoluble substrates. Herein, a fluorescent labeling technique was used to track LPMO action on microcrystalline cellulose and evaluate the impact of CBMs on the distribution of LPMO activity across the fiber surface. Confocal microscopic images revealed that the distribution of oxidized positions on the cellulose surface was CBM-dependent: fluorescent spots were concentrated in reactions with a CBM-containing LPMO whereas they were more dispersed for a CBM-deficient LPMO variant. The more dispersed oxidation pattern for the CBM-free LPMO coincided with the release of fewer soluble reaction products.