Signal Intensity Research Articles

Case report: 10-year follow-up of a patient with neuronal intranuclear inclusion disease and a literature review

Neuronal intranuclear inclusion disease (NIID) is a rare, progressive neurodegenerative disease with variable clinical manifestations. High signals on diffusion-weighted imaging (DWI) along the corticomedullary junction (CMJ) are a specific feature of NIID. Only a few reports have observed patients for a long period and demonstrated a relationship between magnetic resonance imaging (MRI) features and clinical manifestations. Herein, we present a case of a patient with NIID who underwent a 10-year brain MRI follow-up study and a literature review. A 78-year-old woman presented with severe cognitive dysfunction and disturbances of consciousness. Her brain MRI DWI signal intensity gradually increased over 10 years, and her cognitive function progressively declined. The DWI signal changes were related to the clinical manifestations in this case. In the literature review, we analyzed patients with NIID by classifying them into subgroups and found that high signals on fluid-attenuated inversion recovery (FLAIR) and DWI were related to dementia. Although high DWI signals along the CMJ are specific to NIID, many patients also show high signals on FLAIR in the deep subcortical white matter. In our literature review, dementia could have some correlation to MRI signals. In our case with longitudinal follow up, the DWI high intensity signal expansion could have correlation to cognitive decline. We found dementia and the dementia progression may have some relation to expansion of DWI with intensity signals from the CMJ to the deep subcortical white matter. Our report highlights that DWI signal changes are strongly correlated with the clinical manifestations of NIID.

SERS Detection of Hydrophobic Molecules: Thio-β-Cyclodextrin-Driven Rapid Self-Assembly of Uniform Silver Nanoparticle Monolayers and Analyte Trapping

High-sensitivity and repeatable detection of hydrophobic molecules through the surface-enhanced Raman scattering (SERS) technique is a tough challenge because of their weak adsorption and non-uniform distribution on SERS substrates. In this research, we present a simple self-assembly protocol for monolayer SERS mediated by 6-deoxy-6-thio-β-cyclodextrin (β-CD-SH). This protocol allows for the rapid assembly of a compact silver nanoparticle (Ag NP) monolayer at the oil/water interface within 40 s, while entrapping analyte molecules within hotspots. The proposed method shows general applicability for detecting hydrophobic molecules, exemplified as Nile blue, Nile red, fluconazole, carbendazim, benz[a]anthracene, and bisphenol A. The detection limits range from 10−6to 10−9 M, and the relative standard deviations (RSDs) of signal intensity are less than 10%. Moreover, this method was used to investigate the release behaviors of a hydrophobic pollutant (Nile blue) adsorbed on the nanoplastic surface in the water environment. The results suggest that elevated temperatures, increased salinities, and the coexistence of fulvic acid promote the release of Nile blue. This simple and fast protocol overcomes the difficulties related to hotspot accessibility and detection repeatability for hydrophobic analytes, holding out extensive application prospects in environmental monitoring and chemical analysis.

Middle-throughput LC-MS-based platelet proteomics with minute sample amounts using semi-automated positive pressure FASP in 384-well format (PF384)

Comprehensive characterization of platelets requires various functional assays and analysis techniques, including omics-disciplines, each requiring an individual aliquot of a given sample. Consequently, the sample material per assay is often highly limited rendering downscaling a prerequisite for effective sample exploitation. Here we present a transfer of our recently introduced 96-well-based proteomics workflow (PF96) into the 384-well format (PF384) allowing for a significant increase in sensitivity when processing minute platelet protein amounts. In addition, the 4-fold higher throughput (1500 samples per lab worker per week) allows to easily meet the throughput capacities of modern LC-MS instruments. We determined optimal sample loads followed by highlighting the strengths in comparison to our previous sample preparation approach by processing only 3 µg of purified platelet protein from 22 healthy donors. Major advantages are: (I) improved identification and analyte recovery, especially of low copy number proteins, with signal intensity gains of +130 % and +107 % (peptide and protein level, respectively) (II) substantial intensity gains for key-players in platelet activation including the membrane receptors PAR4, P2X1, GPVI, GPV, GPIX and the downstream mediators AKT, PKA, Rap1, Lyn (III) improved reproducibility with a reduction of technical variance from 22 / 25 % down to 16 / 19 % for detection of lower / higher abundant disease markers and (IV) a 4-fold increase in sample preparation throughput. Taken together, these advantages render PF384 a promising future in clinical proteomics and might pave the way of platelet proteomics with minute sample amounts into molecular diagnostics.

The effects of age and other individual factors on radiation induced ESR signals from fingernails

Biodosimetry is crucial for assessing ionizing radiation exposure to guide medical responses. Electron spin resonance (ESR) spectroscopy using fingernails can be effectively used for both occupational and public dose assessments in radiological accidents because of their accessibility and ability to retain stable radiation-induced free radicals. However, despite two decades of research, challenges remain in achieving accurate fingernail dosimetry, mainly owing to the variation in ESR signals among individuals. The purpose of this study was to explore inter-individual differences in ESR signals in fingernails to improve the accuracy and reliability of extremity dosimetry. Fingernail samples were collected from 15 participants (age: 11–64 years), irradiated with X-rays (160 kV, 6.3 mA) at 0, 5, 10, and 20 Gy, and measured using ESR spectroscopy. The effects of individual factors, such as age, sex, health condition, and lifestyle, on radiation-induced ESR signals (RIS) were investigated. Younger participants exhibited stronger RIS intensities and a more linear dose–response relationship. The RIS intensity in female samples tended to be higher than that in male samples. Interestingly, the fingernals of middle-aged donors who regularly took vitamin supplements showed significantly higher ESR signal intensities than those of similar-age donors who did not take supplements. Notable reductions in RIS intensity during storage in a freezer were observed only in older donor samples irradiated at higher doses. These findings underscores the importance of considering age and other individual factors in the calibration for fingernail dosimetry.

Imaging characteristics of hypervascular focal nodular hyperplasia-like lesions in patients with chronic alcoholic liver disease.

Focal nodular hyperplasia (FNH)-like lesions are hyperplastic formations in patients with micronodular cirrhosis and a history of alcohol abuse. Although pathologically similar to hepatocellular carcinoma (HCC) lesions, they are benign. As such, it is important to develop methods to distinguish between FNH-like lesions and HCC. To evaluate diagnostically differential radiological findings between FNH-like lesions and HCC. We studied pathologically confirmed FNH-like lesions in 13 patients with alcoholic cirrhosis [10 men and 3 women; mean age: 54.5 ± 12.5 (33-72) years] who were negative for hepatitis-B surface antigen and hepatitis-C virus antibody and underwent dynamic computed tomography (CT) and magnetic resonance imaging (MRI), including superparamagnetic iron oxide (SPIO) and/or gadoxetic acid-enhanced MRI. Seven patients also underwent angiography-assisted CT. The evaluated lesion features included arterial enhancement pattern, washout appearance (low density compared with that of surrounding liver parenchyma), signal intensity on T1-weighted image (T1WI) and T2-weighted image (T2WI), central scar presence, chemical shift on in- and out-of-phase images, and uptake pattern on gadoxetic acid-enhanced MRI hepatobiliary phase and SPIO-enhanced MRI. Eleven patients had multiple small lesions (< 1.5 cm). Radiological features of FNH-like lesions included hypervascularity despite small lesions, lack of "corona-like" enhancement in the late phase on CT during hepatic angiography (CTHA), high-intensity on T1WI, slightly high- or iso-intensity on T2WI, no signal decrease in out-of-phase images, and complete SPIO uptake or incomplete/partial uptake of gadoxetic acid. Pathologically, similar to HCC, FNH-like lesions showed many unpaired arteries and sinusoidal capillarization. Overall, the present study showed that FNH-like lesions have unique radiological findings useful for differential diagnosis. Specifically, SPIO- and/or gadoxetic acid-enhanced MRI and CTHA features might facilitate differential diagnosis of FNH-like lesions and HCC.

Comparison of dark-field chest radiography and CT for the assessment of COVID-19 pneumonia

BackgroundDark-field chest radiography allows the assessment of the structural integrity of the alveoli by exploiting the wave properties of x-rays.PurposeTo compare the qualitative and quantitative features of dark-field chest radiography in patients with COVID-19 pneumonia with conventional CT imaging.Materials and methodsIn this prospective study conducted from May 2020 to December 2020, patients aged at least 18 years who underwent chest CT for clinically suspected COVID-19 infection were screened for participation. Inclusion criteria were a CO-RADS score ≥4, the ability to consent to the procedure and to stand upright without help. Participants were examined with a clinical dark-field chest radiography prototype. For comparison, a healthy control cohort of 40 subjects was evaluated. Using Spearman's correlation coefficient, correlation was tested between dark-field coefficient and CT-based COVID-19 index and visual total CT score as well as between the visual total dark-field score and the visual total CT score.ResultsA total of 98 participants [mean age 58 ± 14 (standard deviation) years; 59 men] were studied. The areas of signal intensity reduction observed in dark-field images showed a strong correlation with infiltrates identified on CT scans. The dark-field coefficient had a negative correlation with both the quantitative CT-based COVID-19 index (r = −.34, p = .001) and the overall CT score used for visual grading of COVID-19 severity (r = −.44, p &amp;lt; .001). The total visual dark-field score for the presence of COVID-19 was positively correlated to the total CT score for visual COVID-19 severity grading (r = .85, p &amp;lt; .001).ConclusionCOVID-19 pneumonia-induced signal intensity losses in dark-field chest radiographs are consistent with CT-based findings, showing the technique's potential for COVID-19 assessment.

The Influence of the Supporting Substrate on Single‐Particle Circular Differential Scattering of DNA Assembled Nanorod Dimers

AbstractSingle‐particle measurements of chiral nanostructures have the potential to offer more detailed insights compared to the ensemble‐averaged signals obtained in ensemble circular dichroism spectroscopy. For instance, single‐particle circular differential scattering (CDS) studies have revealed the effects of structural heterogeneity in chiral plasmonic nanostructures. However, differential light‐matter interactions of 3D chiral nanostructures caused by diverse orientations on the supporting substrate remain largely unexplored. Here, the CDS of DNA origami‐templated twisted gold nanorod (AuNR) dimers on a glass support is investigated. With the help of correlated scanning electron microscopy and electromagnetic simulations, it is demonstrated how the broad diversity of spectral lineshapes and signal intensities as well as sign of the CDS originates mainly from four different orientations of the chiral dimer once deposited from solution on the substrate and dried. Most surprisingly, it is found that even for the same enantiomer a sign reversal is possible depending solely on the dimer orientation when deposited on the support. These results are important for the correct interpretation of single‐particle chiroptical studies and furthermore provide valuable insights into the design of substrate‐supported chiral plasmonic metamaterials.

Damage Evolution Characteristics of Steel-Fiber-Reinforced Cellular Concrete Based on Acoustic Emission

In order to investigate the steel fiber parameters on the damage characteristics and crack evolution of cellular concrete materials, uniaxial compression–acoustic emission combined tests were carried out on steel-fiber-reinforced cellular concrete (SFRCC) with different steel fiber contents (0%, 0.5%, 1%, 1.5%, and 2%) and different porosities (10% and 20%). The material damage evolution characteristics were analyzed by acoustic emission parameters and IB values, and the crack types were identified using Gaussian mixture clustering method (GMM) pairs. The results show the following: the inclusion of steel fibers increased the compressive strength of cellular concrete by 19.8~46.3% at 10% porosity, and by 37.1~102.2% at 20% porosity; the addition of steel fibers significantly increased the density and intensity of the acoustic emission signals; the decreasing tendency of the IB value at the peak stress slowed down with the increase in the amount of steel fibers, and the steel fibers could effectively inhibit the crack development; crack classification results show that the proportion of shear cracks in all stages of cellular concrete increased significantly after the addition of steel fibers.

A mouse coccygeal intervertebral disc degeneration model with tail-looping constructed using a suturing method.

Intervertebral disc degeneration (IDD) is one of the common degenerative diseases. Due to ethical constraints, it is difficult to obtain sufficient research on humans, so the use of an animal model of IDD is very important to clarify the pathogenesis and treatment mechanism of the disease. In this study, thirty 2-month-old mice were selected for operation to establish a coccygeal IDD model. The distal tail portion of the tail (beyond the 17th coccygeal vertebra) and a small piece of skin above the 8th coccygeal vertebra were excised, and the two incisions were brought together after flexion, and secured with sutures. The heights and signal intensities of the intervertebral discs (IVDs) were assessed using microcomputed tomography (μCT) and magnetic resonance imaging (MRI) at 0, 6, 12 weeks postoperatively. The overall tissue morphology, cell distribution and density, and extracellular matrix of the IVDs were also assessed using Hematoxylin and Eosin (HE), Safranin O-Fast Green and immunohistochemical staining. All mice in the experimental group survived after the operation, and there were no complications such as wound infection, tail necrosis and suture shedding. The experimental results demonstrated that the suturing method can successfully initiate IDD. Different severity levels of IDD can be induced by controlling the bending angle of the IVDs within the tail loop; however, for consistency, histologic and imaging results should be obtained at the same bending angle and looping period. This IDD model is an effective method for studying the etiology and treatment of degenerative IVD disease.

An Acta Orthopaedica educational article: Treatment of pediatric spondylolysis and spondylolisthesis.

Spondylolysis is defined as a defect or elongation in the pars interarticularis of the lumbar spine, either unilateral or bilateral. Growing children with bilateral spondylolysis may develop spondylolisthesis, i.e., forward slipping of the affected vertebra. The etiology of spondylolysis is regarded as a stress fracture due to repetitive loading associated with a genetic predisposition. Lumbar magnetic resonance imaging (MRI) shows an increased signal intensity before an actual fracture line develops. In low grade spondylolisthesis, two-thirds of children with acute pediatric spondylolysis will undergo bony union with early activity restriction. Health-related quality of life is improved in patients achieving bony union as compared with patients having non-union, of which one-fourth will additionally develop spondylolisthesis. In patients with high-grade spondylolisthesis, defined as a more than 50% forward slippage of the affected vertebra, spinal fusion is recommended to prevent further progression.

The MRI-based vertebral bone quality score is a predictor of pedicle screw loosening following instrumented posterior lumbar fusion

Objective: To investigate the predictive ability of the MRI-based vertebral bone quality (VBQ) score for pedicle screw loosening following instrumented transforaminal lumbar interbody fusion (TLIF). Methods: Data from patients who have received one or two-level instrumented TLIF from February 2014 to March 2015 were retrospectively collected. Pedicle screw loosening was diagnosed when the radiolucent zone around the screw exceeded 1 mm in plain radiographs. The T1-weighted MRI sagittal images were used for calculation of the VBQ score. The score was calculated with the median signal intensity value of L1 to L4 divided by the signal intensity value of cerebrospinal fluid at the L3 level. Univariate analysis and multivariate binary logistic regression analysis were performed. Receiver operating characteristic curve analysis assessed the predictive ability of the VBQ score on screw loosening. Results: Among the included 211 patients, 75 of them (35.55%) had pedicle screw loosening at the 24 month follow-up. Multivariable logistic regression analyses demonstrated that higher VBQ score (OR: 27.887 ± 0.514 ,95% CI: 10.189–76.326), male sex (female to male 0.323 ± 0.483, 0.126–0.833), and longer fusion length (2.578 ± 0.545, 1.166–5.701) were significant influencing factors for pedicle screw loosening. The VBQ score significantly predicted screw loosening with an accuracy of 78.9%. Conclusions: A higher VBQ score was an independent risk factor for pedicle screw loosening following instrumented TLIF. The MRI-based VBQ score showed good predictive ability for screw loosening and could be used as an alternative option for preoperative bone quality evaluation.

Exploring Quantitative MRI Biomarkers of Head and Neck Post-Radiation Lymphedema and Fibrosis: Post Hoc Analysis of a Prospective Trial.

Quantifying head and neck lymphedema and fibrosis (HN-LEF) is crucial in the investigation and management of treatment sequelae in head and neck cancer (HNC). The T1- and T2-weighted MRI signal intensity (SI) was examined in relation to HN-LEF categories per physical/tactile examination (No-LEF, A-B = edema, C = edema + fibrosis, D = fibrosis), and MRI structural volumes were examined in relation to a novel 10-point HN-LEF score in the intraoral and submental regions. We identified differences in ranks among HN-LEF categories in relation to the MRI SI (A-B and C are higher than D and No-LEF for T2 SI, and A-B is the highest for T1). Furthermore, six pairs of FOM volumes on MRI demonstrated a strong negative correlation (p < 0.05) with the HN-LEF score at adjacent palpable sites. Both MRI SI and structural volumes can potentially be imaging biomarkers of edematous soft tissue states in HNC patients.

Identification of Sulcal Hyperintense Vessel (Vessel Wall MR Ivy Sign) in Adult Moyamoya Disease with High-resolution Vessel Wall Imaging : A Pilot Study.

The leptomeningeal ivy sign is a distinctive finding of moyamoya disease (MMD), characterized by a linear high signal intensity along the cortical sulci on contrast-enhanced T1 magnetic resonance imaging (MRI) and fluid-attenuated inversion-recovery MRI. We recently identified a similar linear enhancement along the cortical sulci using gadolinium-enhanced vessel wall MRI (VWMR) in patients with MMD. The aim of this study was to introduce the concept of the "VWMR ivy sign (VIS)". Eighteen MMD patients underwent gadolinium-enhanced VWMR. We identified the VIS in gadolinium-enhanced VWMR, represented by a linear high intensity along the cortical sulci. The VIS was assessed by comparing pre and postcontrast T1 black blood sequences on VWMR and was investigated in the precentral, central, and postcentral sulci. "VIS scores" were calculated by the sum of VIS in the three sulci, ranged from 0 to 3. We compared the VIS scores according to different stroke presentations (non-stroke, ischemic stroke, and hemorrhagic stroke). The inter-modality agreement for identifying VIS and fluid-attenuated inversion-recovery (FLAIR)/cortical sulci on contrast-enhanced T1 MRI (CEMR) ivy sign was determined using Cohen's kappa statistics. The VIS scores were significantly different among the three groups (P = 0.004). The VIS scores in both the ischemic and hemorrhagic groups were significantly higher than those in the non-stroke group (ischemic vs. non-stroke, P = 0.009; hemorrhagic vs. non-stroke, P = 0.004). After adjusting for age and sex using the non-stroke group as a reference group, the VIS scores were significantly higher in the ischemic and hemorrhagic groups (P=0.046, OR 8.27, 95% CI 1.03-66.19 and P=0.039, OR 7.78, 95% CI 1.11-54.48, respectively). Inter-modality agreement between VIS and FLAIR ivy sign was substantial, perfect, and substantial in the precentral, central, and postcentral sulci, respectively (precentral sulcus, κ=0.609, 95% CI=0.213-1; central sulcus, κ=1; and postcentral sulcus, κ=0.769, 95% CI=0.475-1). Inter-modality agreement between the VIS and CEMR ivy sign was substantial in the precentral, central, and postcentral sulci, respectively (precentral sulcus, κ=0.727, 95% CI=0.384-1; central sulcus, κ=0.609, 95% CI=0.384-1; and postcentral sulcus, κ=0.649, 95% CI=0.310-0.998). This preliminary series introduces the concept of VIS, possibly indicating slow and retrograde flow of sulcal vessels via leptomeningeal collaterals. Future studies are needed to develop an optimal scoring system for VIS and establish its clinical correlation with stroke presentations in MMD patients.

Long-term effects of linear versus macrocyclic GBCAs on gene expression in the central nervous system of mice

BackgroundWe examined chronic gadolinium retention impact on gene expression in the mouse central nervous system (CNS) after injection of linear or macrocyclic gadolinium-based contrast agents (GBCAs).MethodsFrom 05/2022 to 07/2023, 36 female mice underwent weekly intraperitoneal injections of gadodiamide (2.5 mmol/kg, linear), gadobutrol (2.5 mmol/kg, macrocyclic), or saline. Mice were sacrificed on day 29 or 391 after a 1-year washout. Assessments included magnetic resonance imaging (MRI), mechanical hyperalgesia tests, and inductively coupled plasma mass spectrometry to measure gadolinium levels. Ribonucleic acid (RNA) sequencing and bioinformatic analyses identified differentially expressed genes (DEGs), with validation by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB).ResultsPost-gadodiamide, MRI showed increased signal intensity in the deep cerebellar nuclei (pre, 0.997 ± 0.006 versus post, 1.086 ± 0.013, p < 0.001). Mechanical hyperalgesia tests indicated transient sensory changes. After 1-year, gadolinium retention was noted in the brain (5.92 ± 0.32 nmol/kg) and spinal cord (1.23 ± 0.66 nmol/kg) with gadodiamide, compared to saline controls (0.06 ± 0.02 nmol/kg in brains and 0.28 ± 0.06 nmol/kg in spinal cords). RNA sequencing identified 17 shared DEGs between brain and spinal cord in the gadodiamide group on day 391, with altered Hmgb2 and Sgk1 expression confirmed by qRT-PCR and WB. Reactome pathway analysis showed enrichment in neuroinflammation pathways. No DEGs were detected in brains on day 29.ConclusionChronic gadolinium deposition from repeated linear GBCA but not macrocyclic administration causes significant gene expression alterations in the mouse CNS, particularly affecting neuroinflammation pathways.Relevance statementThis study examined the long-term impact of chronic gadolinium retention on gene expression in the mouse CNS, uncovering significant changes associated with neuroinflammation pathways after repeated administration of linear GBCA, but not with macrocyclic GBCA. These findings highlight the importance of further research on the long-term safety of linear GBCA in medical imaging.Key PointsChronic gadolinium retention alters gene expression in the mouse central nervous system.Significant neuroinflammatory pathway changes were observed after linear gadodiamide exposure.MRI showed increased signal intensity in deep cerebellar nuclei after gadodiamide injection.Graphical

False-Positive Uptake of 123I-MIBG in the Basal Ganglion in a Pediatric Neuroblastoma Patient.

A 7-year-old boy with high-risk neuroblastoma underwent 123I-MIBG SPECT/CT to evaluate the therapy response. The scan revealed abnormal 123I-MIBG uptake in the left basal ganglion, indicating the possibility of brain metastasis. Subsequent contrast-enhanced brain MRI, however, did not show any abnormal signal intensity in the left basal ganglion. Follow-up 123I-MIBG SPECT/CT scans at 3-month and 9-month also did not show abnormal MIBG uptake in the same area. The case highlights the possibility of false-positive uptake of 123I-MIBG in the basal ganglion.

LGR5 as a diagnostic marker for dysplasia in serrated polyps

AimsWNT signalling pathway dysregulation is often a critical early component in colorectal neoplasia, particularly the chromosomal instability pathway. Using two WNT reporters, LGR5 and AXIN2, we sought to assess whether...

Impact of A1 segment asymmetry on hemodynamic conditions around the circle of Willis and anterior communicating artery aneurysm formation

BackgroundThis study aims to investigate how A1 segment asymmetry—also known as A1 dominancy—influences the development of the anterior communicating artery aneurysm (AcomA) as it affects hemodynamic conditions within the circle of Willis (COW). Using time-of-flight magnetic resonance angiography (TOF-MRA), the research introduces a novel approach to assessing shear stress in A1 segments to uncover the hemodynamic factors contributing to AcomA formation.MethodAn observational study was conducted over 6 years at a tertiary university hospital’s outpatient clinic. Recruited patients who underwent TOF-MRA imaging were divided into AcomA and non-AcomA groups. MRA images were analyzed using semi-automatic software (VINT, Mediimg, Inc.) to calculate the signal intensity gradient (SIG), which reflects wall shear stress. The comparison metrics included general demographics, anatomical characteristics, and hemodynamic attributes of the COW, mainly focusing on A1 segment asymmetry.ResultsAmong the 700 subjects, 106 were categorized into the AcomA group, while 594 were placed in the non-AcomA group. The AcomA group showed a more significant difference in the bilateral A1 diameter (49.0% vs. 20.8%, p &amp;lt; 0.001) and a greater prevalence of unilateral A1 aplasia (32.1% vs. 6.7%, p &amp;lt; 0.001) compared to the non-AcomA group. Increased bilateral A1 asymmetry in the AcomA group corresponded with notable variations in A1 SIG, indicating increased wall shear stress. The occurrence of AcomA is associated with both anatomical factors of the circle of Willis, represented by the bilateral A1 diameter ratio, and hemodynamic factors, represented by the bilateral A1 SIG ratio, suggesting that both factors are almost equally significant.ConclusionOur findings suggest that A1 segment asymmetry influences hemodynamic changes within the COW, contributing to AcomA formation. Hemodynamic factors provide an intuitive understanding of how anatomical characteristics within the COW can lead to aneurysm development.

Effectiveness of Different Organic Solvent Additions to Water Samples for Reducing the Adsorption Effects of Organic Pesticides Using Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

This study systematically investigated the effect of organic solvent addition on the detection signal intensity of 15 organic pesticides in water using ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS). The analysis of chromatographic peak area ratios in ultrapure water (UPW) versus 30% methanol (MeOH)-UPW showed that the adsorption effects (AEs, mainly from injection vials with weaker polarity) were the main factor influencing the detection intensity of the organic pesticides. The AEs varied with pesticide type and concentration, especially for those with high logKow values and longer retention times, such as malathion, triadimefon, prometryn, S-metolachlor, diazinon, and profenofos. Significant differences were observed in the ability of five organic solvents (MeOH, dimethyl sulfoxide, isopropanol, acetonitrile, and acetone) to reduce AEs, with MeOH being the most effective. Optimal solvent ratios were determined to minimize AEs in aqueous solutions. Additionally, plastic injection vials caused greater AEs than glass injection vials, but the addition of organic solvents increased the detection intensity of the analytes for vials of both materials. Density functional theory calculations of the binding energies between pesticides (diazinon, malathion, and S-metolachlor) and vial materials further confirmed the effect of AE on the detection intensity of the analytes. This study showed that the addition of MeOH to real water samples effectively reduced or eliminated the effects of AEs, achieving a good linearity of calibration curves (0.05/0.1-5 μg/L, R2 = 0.9853-0.9998), high sensitivity (LOD = 5-32 ng/L), precision (RSD = 1.4-14.5%), and accuracy (average recoveries = 80.6-121.8%). These results provide technical and methodological support for mitigating the effects of AEs on pesticide detection in water using UHPLC-ESI-MS/MS.

Vessels encapsulating tumor clusters contribute to the intratumor heterogeneity of HCC on Gd-EOB-DTPA-enhanced MRI.

Vessels encapsulating tumor clusters (VETC) pattern is tumor vasculature of HCC and is a predictor of prognosis and therapeutic efficacy. Recent radiological studies have demonstrated the predictability of VETC from preoperative images, but the mechanisms of image formation are not elucidated. This study aims to determine the relationship between VETC and intratumor heterogeneity in Gd-EOB-DTPA-enhanced magnetic resonance imaging (EOB-MRI) and to provide its pathological evidence. Radiologists visually classified preoperative arterial- and hepatobiliary-phase EOB-MRI images of 204 surgically resected HCCs into patterns based on heterogeneity and signal intensity; these classifications were validated using texture analysis. Single and multiplex immunohistochemistry for CD34, h-caldesmon, and OATP1B3 were performed to evaluate VETC, arterial vessel density (AVD), and OATP1B3 expression. Recurrence-free survival was assessed using the generalized Wilcoxon test. The contribution of clinicoradiological factors to the prediction of VETC was evaluated by random forest and least absolute shrinkage and selection operator regression. VETC was frequently found in tumors with arterial-phase heterogeneous hyper-enhancement patterns and in tumors with hepatobiliary-phase heterogeneous hyperintense/isointense patterns (HBP-Hetero). AVD and OATP1B3 expression positively correlated with signal intensity in the arterial and hepatobiliary phases, respectively. Intratumor spatial analysis revealed that AVD and OATP1B3 expression were lower in VETC regions than in tumor regions without VETC. Patients with HBP-Hetero tumors had shorter recurrence-free survival. Machine learning models highlighted the importance of serum PIVKA-II, tumor size, and enhancement pattern of arterial and hepatobiliary phase for VETC prediction. VETC is associated with local reductions of both AVD and OATP1B3 expression, likely contributing to heterogeneous enhancement patterns in EOB-MRI. Evaluation of the arterial and hepatobiliary phases of EOB-MRI would enhance the predictability of VETC.

Mitochondrial Morphofunctional Profiling in Primary Human Skin Fibroblasts Using TMRM and Mitotracker Green Co-staining.

Mitochondrial morphology and membrane potential (Δψ) are important readouts of mitochondrial function. Integrated analysis of these parameters in living cells can be performed using fluorescent lipophilic cations, which enter cells and accumulate in the mitochondrial matrix in a Δψ-dependent manner. Here, we describe the use of tetramethylrhodamine methyl ester (TMRM) and Mitotracker Green FM (MG) for mitochondrial morphology and semiquantitative Δψ analysis in living primary human skin fibroblasts (PHSFs). Practically, we present an integrated protocol to quantify mitochondrial morphology parameters and signal intensity using epifluorescence microscopy of PHSFs co-stained with TMRM and MG. This approach performs best using large flat cells like PHSFs, which display a high mitochondria-specific fluorescence signal and are imaged at a relatively high (x40) magnification.