Diffuse Changes Research Articles

Congestive Hepatopathy: Pathophysiology, Workup, and Imaging Findings with Pathologic Correlation.

Liver congestion is increasingly encountered in clinical practice and presents diagnostic pitfalls of which radiologists must be aware. The complex altered hemodynamics associated with liver congestion leads to diffuse parenchymal changes and the development of benign and malignant nodules. Distinguishing commonly encountered benign hypervascular lesions, such as focal nodular hyperplasia (FNH)-like nodules, from hepatocellular carcinoma (HCC) can be challenging due to overlapping imaging features. FNH-like lesions enhance during the hepatic arterial phase and remain isoenhancing relative to the background liver parenchyma but infrequently appear to wash out at delayed phase imaging, similar to what might be seen with HCC. Heterogeneity, presence of an enhancing capsule, washout during the portal venous phase, intermediate signal intensity at T2-weighted imaging, restricted diffusion, and lack of uptake at hepatobiliary phase imaging point toward the diagnosis of HCC, although these features are not sensitive individually. It is important to emphasize that the Liver Imaging Reporting and Data System (LI-RADS) algorithm cannot be applied in congested livers since major LI-RADS features lack specificity in distinguishing HCC from benign hypervascular lesions in this population. Also, the morphologic changes and increased liver stiffness caused by congestion make the imaging diagnosis of cirrhosis difficult. The authors discuss the complex liver macro- and microhemodynamics underlying liver congestion; propose a more inclusive approach to and conceptualization of liver congestion; describe the pathophysiology of liver congestion, hepatocellular injury, and the development of benign and malignant nodules; review the imaging findings and mimics of liver congestion and hypervascular lesions; and present a diagnostic algorithm for approaching hypervascular liver lesions. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Erythrocytes membrane fluidity changes induced by adenylyl cyclase cascade activation: study using fluorescence recovery after photobleaching.

In this study, fluorescence recovery after photobleaching (FRAP) experiments were performed on RBC labeled by lipophilic fluorescent dye CM-DiI to evaluate the role of adenylyl cyclase cascade activation in changes of lateral diffusion of erythrocytes membrane lipids. Stimulation of adrenergic receptors with epinephrine (adrenaline) or metaproterenol led to the significant acceleration of the FRAP recovery, thus indicating an elevated membrane fluidity. The effect of the stimulation of protein kinase A with membrane-permeable analog of cAMP followed the same trend but was less significant. The observed effects are assumed to be driven by increased mobility of phospholipids resulting from the weakened interaction between the intermembrane proteins and RBC cytoskeleton due to activation of adenylyl cyclase signaling cascade.

A rare case of atypical intradural extramedullary glioblastoma diagnosed utilizing next-generation sequencing and methylation profiling: illustrative case.

Primary spinal cord tumors, especially primary spinal cord glioblastoma multiforme (PSC-GBM), are exceptionally rare, accounting for less than 1.5% of all spinal tumors. Their infrequency and aggressive yet atypical presentation make diagnosis challenging. In uncertain cases, a surgical approach for tissue diagnosis is often optimal. A 76-year-old male presented with a rapidly progressing clinical history marked by worsening extremity weakness, urinary retention, and periodic fecal incontinence alongside diffuse changes on neuraxis imaging. The patient, in whom subacute polyneuropathy was initially diagnosed, received multiple rounds of steroids and intravenous immunoglobulin without clinical improvement. Histopathological review of the biopsy tissue yielded an initial diagnosis of spindle cell neoplasm. Next-generation sequencing (NGS) is done routinely on all neuropathology specimens at the authors' institution, and methylation profiling is pursued in difficult cases. Ultimately, NGS and methylation profiling results were essential to an integrated final diagnosis of GBM. PSC-GBM is a rare but highly aggressive occurrence of this tumor. Prolonged back pain, rapid neurological decline, and imaging changes warrant the consideration of lesional biopsy for precise disease characterization. In inconclusive cases, NGS has proved invaluable for clinical clarification and diagnosis, underscoring its importance for integrated diagnoses in guiding appropriate treatment strategies.

Diffusion Weighted Magnetic Resonance Imaging of Spinal Cord Injuries After Instrumented Fusion Stabilization.

Diffusion-weighted magnetic resonance imaging (DW-MRI) is a promising technique for assessing spinal cord injury (SCI) that has historically been challenged by the presence of metallic stabilization hardware. This study leverages recent advances in metal-artifact resistant multi-spectral DW-MRI to enable diffusion quantification throughout the spinal cord even after fusion stabilization. Twelve participants with cervical spinal cord injuries treated with fusion stabilization and 49 asymptomatic able-bodied control participants underwent multi-spectral DW-MRI evaluation. Apparent diffusion coefficient (ADC) values were calculated in axial cord sections. Statistical modeling assessed ADC differences across cohorts and within distinct cord regions of the SCI participants (at, above, or below injured level). Computed models accounted for subject demographics and injury characteristics. ADC was found to be elevated at injured levels compared with non-injured levels (z = 3.2, p = 0.001), with ADC at injured levels decreasing over time since injury (z = -9.2, p < 0.001). Below the injury level, ADC was reduced relative to controls (z = -4.4, p < 0.001), with greater reductions after more severe injuries that correlated with lower extremity motor scores (z = 2.56, p = 0.012). No statistically significant differences in ADC above the level of injury were identified. By enabling diffusion analysis near fusion hardware, the multi-spectral DW-MRI technique allowed intuitive quantification of cord diffusion changes after SCI both at and away from injured levels. This demonstrates the approach's potential for assessing post-surgical spinal cord integrity throughout stabilized regions.

Pedigree Analysis of Nonclassical Cholesteryl Ester Storage Disease with Dominant Inheritance in a LIPA I378T Heterozygous Carrier.

Cholesterol ester storage disorder (CESD; OMIM: 278,000) was formerly assumed to be an autosomal recessive allelic genetic condition connected to diminished lysosomal acid lipase (LAL) activity due to LIPA gene abnormalities. CESD is characterized by abnormal liver function and lipid metabolism, and in severe cases, liver failure can occur leading to death. In this study, one Chinese nonclassical CESD pedigree with dominant inheritance was phenotyped and analyzed for the corresponding gene alterations. Seven males and eight females from nonclassical CESD pedigree were recruited. Clinical features and LAL activities were documented. Whole genome Next-generation sequencing(NGS) was used to screen candidate genes and mutations, Sanger sequencing confirmed predicted mutations, and qPCR detected LIPA mRNA expression. Eight individuals of the pedigree were speculatively thought to have CESD. LAL activity was discovered to be lowered in four living members of the pedigree, but undetectable in the other four deceased members who died of probable hepatic failure. Three of the four living relatives had abnormal lipid metabolism and all four had liver dysfunctions. By liver biopsy, the proband exhibited diffuse vesicular fatty changes in noticeably enlarged hepatocytes and Kupffer cell hyperplasia. Surprisingly, only a newly discovered heterozygous mutation, c.1133T>C (p. Ile378Thr) on LIPA, was found by gene sequencing in the proband. All living family members who carried the p.I378T variant displayed reduced LAL activity. Phenotypic analyses indicate that this may be an autosomal dominant nonclassical CESD pedigree with a LIPA gene mutation.

Analytic shock‐fronted solutions to a reaction–diffusion equation with negative diffusivity

AbstractReaction–diffusion equations (RDEs) model the spatiotemporal evolution of a density field according to diffusion and net local changes. Usually, the diffusivity is positive for all values of , which causes the density to disperse. However, RDEs with partially negative diffusivity can model aggregation, which is the preferred behavior in some circumstances. In this paper, we consider a nonlinear RDE with quadratic diffusivity that is negative for . We use a nonclassical symmetry to construct analytic receding time‐dependent, colliding wave, and receding traveling wave solutions. These solutions are multivalued, and we convert them to single‐valued solutions by inserting a shock. We examine properties of these analytic solutions including their Stefan‐like boundary condition, and perform a phase plane analysis. We also investigate the spectral stability of the and constant solutions, and prove for certain and that receding traveling waves are spectrally stable. In addition, we introduce a new shock condition where the diffusivity and flux are continuous across the shock. For diffusivity symmetric about the midpoint of its zeros, this condition recovers the well‐known equal‐area rule, but for nonsymmetric diffusivity it results in a different shock position.

The Impact of Vertical Eddy Diffusivity Changes in the CMAQ Model on PM2.5 Concentration Variations in Northeast Asia: Focusing on the Seoul Metropolitan Area

The vertical eddy diffusion process plays a crucial role in PM2.5 prediction, yet accurately predicting it remains challenging. In the three-dimensional atmospheric chemistry transport model (3-D AQM) CMAQ, a parameter, Kz, is utilized, and it is known that PM2.5 prediction tendencies vary according to the floor value of this parameter (Kzmin). This study aims to examine prediction characteristics according to Kzmin values, targeting days exceeding the Korean air quality standards, and to derive appropriate Kzmin values for predicting PM2.5 concentrations in the DJFM Seoul Metropolitan Area (SMA). Kzmin values of 0.01, 0.5, 1.0, and 2.0, based on the model version and land cover, were applied as single values. Initially focusing on December 4th to 12th, 2020, the prediction characteristics were examined during periods of local and inflow influence. Results showed that in both periods, as Kzmin increased, surface concentrations over land decreased while those in the upper atmosphere increased, whereas over the sea, concentrations increased in both layers due to the influence of advection and diffusion without emissions. During the inflow period, the increase in vertically diffused pollutants led to increased inflow concentrations and affected contribution assessments. Long-term evaluations from December 2020 to March 2021 indicated that the prediction performance was superior when Kzmin was set to 0.01, but it was not significant for the upwind region (China). To improve trans-boundary effects, optimal values were applied differentially by region (0.01 for Korea, 1.0 for China, and 0.01 for other regions), resulting in significantly improved prediction performance with an R of 0.78, IOA of 0.88, and NMB of 0.7%. These findings highlight the significant influence of Kzmin values on winter season PM2.5 prediction tendencies in the SMA and underscore the need for considering differential application of optimal values by region when interpreting research and making policy decisions.

Oligodendrocyte progenitor cells' fate after neonatal asphyxia-Puzzling implications for the development of hypoxic-ischemic encephalopathy.

Premature birth or complications during labor can cause temporary disruption of cerebral blood flow, often followed by long-term disturbances in brain development called hypoxic-ischemic (HI) encephalopathy. Diffuse damage to the white matter is the most frequently detected pathology in this condition. We hypothesized that oligodendrocyte progenitor cell (OPC) differentiation disturbed by mild neonatal asphyxia may affect the viability, maturation, and physiological functioning of oligodendrocytes. To address this issue, we studied the effect of temporal HI in the in vivo model in P7 rats with magnetic resonance imaging (MRI), microscopy techniques and biochemical analyses. Moreover, we recreated the injury in vitro performing the procedure of oxygen-glucose deprivation on rat neonatal OPCs to determine its effect on cell viability, proliferation, and differentiation. In the in vivo model, MRI evaluation revealed changes in the volume of different brain regions, as well as changes in the directional diffusivity of water in brain tissue that may suggest pathological changes to myelinated neuronal fibers. Hypomyelination was observed in the cortex, striatum, and CA3 region of the hippocampus. Severe changes to myelin ultrastructure were observed, including delamination of myelin sheets. Interestingly, shortly after the injury, an increase in oligodendrocyte proliferation was observed, followed by an overproduction of myelin proteins 4 weeks after HI. Results verified with the in vitro model indicate, that in the first days after damage, OPCs do not show reduced viability, intensively proliferate, and overexpress myelin proteins and oligodendrocyte-specific transcription factors. In conclusion, despite the increase in oligodendrocyte proliferation and myelin protein expression after HI, the production of functional myelin sheaths in brain tissue is impaired. Presented study provides a detailed description of oligodendrocyte pathophysiology developed in an effect of HI injury, resulting in an altered CNS myelination. The described models may serve as useful tools for searching and testing effective of effective myelination-supporting therapies for HI injuries.

Oral epithelial dysplasia with lymphocytic immune response: clinicopathological characterisation of 44 cases.

Oral epithelial dysplasia (OED) often exhibits a lymphocytic/lichenoid immune response (LIR), imparting histological resemblance to lichenoid mucositis and rendering diagnosis challenging. The clinical appearances of OED and lichenoid inflammatory processes are generally divergent, presenting as well-demarcated hyperkeratotic plaques and diffuse white and/or red mucosal change with variably prominent Wickham striae, respectively. To date, clinicopathological characterisation of OED with LIR, including clinical/gross appearance, has not been depicted. Cases of solitary OED with LIR for which a clinical photograph was available were identified in the authors' institutional files. Clinical and histological features were documented. In 44 identified cases, dysplasia was mild (19 of 44, 43.2%), moderate (19 of 44, 43.2%) and severe (six of 44, 13.6%). Clinically/grossly, all 44 cases (100.0%), presented as well-demarcated hyperkeratotic plaques lacking diffuse white-and-red mucosal change or Wickham striae. Histologically, OED with LIR exhibited numerous 'lichenoid' features beyond the lymphocytic band in the superficial lamina propria, including: leucocyte transmigration (38 of 44, 86.4%), spongiosis (37 of 44, 84.1%), Civatte/colloid bodies (36 of 44, 81.8%), basal cell degeneration (29 of 45, 65.9%), sawtooth rete ridges (11 of 44, 25.0%) and subepithelial clefting (7 of 44, 15.9%). Virtually any lichenoid histological feature may be seen in OED with LIR, representing a significant diagnostic pitfall. The typical clinical appearance of OED with LIR is of a well-demarcated hyperkeratotic plaque, characteristic of keratinising dysplasia and devoid of lichenoid features. This suggests that pathologist access to clinical photographs during diagnostic interpretation of biopsied white lesions, which represents opportunity to perform gross examination of the disease process, may reduce interobserver variability and improve diagnostic accuracy in this challenging differential diagnosis.

ВЛИЯНИЕ ПРИМЕСЕЙ НА ДЕГРАДАЦИЮ СОЕДИНЕНИЙ В СИСТЕМЕ Al – Au

Typical reasons for degradation of micro–welded bimetallic compounds of the aluminum-gold binary system are considered. These types of compounds are often used in the manufacture of semiconductor products (SCPs) and integrated circuits (ICs). Degradation of compounds, revealed during screen tests or during products operating, leads to failures, which dramatically reduces the reliability of electronic equipment (EE). The majority of degradation processes are based on diffusion phenomena, which are mainly determined by temperature, chemical composition and microstructure of metals and alloys. Impurity elements included in the gold coating have a significant effect on the degradation of the wire connections such as crystal contact pads – traverses of package terminals of SCPs. In this regard, it is worth analyzing the effect of various impurities on the diffusion processes and changes in the microstructure of the coating in order to find out the most dangerous chemical elements and determine their role in the degradation of compounds. The paper presents a review of references on the research subject. In the conclusion, the results of analysis in the field of the influence of impurity elements on the degradation of compounds in Al – Au system are summarized, conclusions are drawn about the key role of grain-boundary diffusion on the degradation of micro-welded bimetallic compounds.

Repeatability quantification of brain diffusion-weighted imaging for future clinical implementation at a low-field MR-linac

BackgroundLongitudinal assessments of apparent diffusion coefficients (ADCs) derived from diffusion-weighted imaging (DWI) during intracranial radiotherapy at magnetic resonance imaging-guided linear accelerators (MR-linacs) could enable early response assessment by tracking tumor diffusivity changes. However, DWI pulse sequences are currently unavailable in clinical practice at low-field MR-linacs. Quantifying the in vivo repeatability of ADC measurements is a crucial step towards clinical implementation of DWI sequences but has not yet been reported on for low-field MR-linacs. This study assessed ADC measurement repeatability in a phantom and in vivo at a 0.35 T MR-linac.MethodsEleven volunteers and a diffusion phantom were imaged on a 0.35 T MR-linac. Two echo-planar imaging DWI sequence variants, emphasizing high spatial resolution (“highRes”) and signal-to-noise ratio (“highSNR”), were investigated. A test–retest study with an intermediate outside-scanner-break was performed to assess repeatability in the phantom and volunteers’ brains. Mean ADCs within phantom vials, cerebrospinal fluid (CSF), and four brain tissue regions were compared to literature values. Absolute relative differences of mean ADCs in pre- and post-break scans were calculated for the diffusion phantom, and repeatability coefficients (RC) and relative RC (relRC) with 95% confidence intervals were determined for each region-of-interest (ROI) in volunteers.ResultsBoth DWI sequence variants demonstrated high repeatability, with absolute relative deviations below 1% for water, dimethyl sulfoxide, and polyethylene glycol in the diffusion phantom. RelRCs were 7% [5%, 12%] (CSF; highRes), 12% [9%, 22%] (CSF; highSNR), 9% [8%, 12%] (brain tissue ROIs; highRes), and 6% [5%, 7%] (brain tissue ROIs; highSNR), respectively. ADCs measured with the highSNR variant were consistent with literature values for volunteers, while smaller mean values were measured for the diffusion phantom. Conversely, the highRes variant underestimated ADCs compared to literature values, indicating systematic deviations.ConclusionsHigh repeatability of ADC measurements in a diffusion phantom and volunteers’ brains were measured at a low-field MR-linac. The highSNR variant outperformed the highRes variant in accuracy and repeatability, at the expense of an approximately doubled voxel volume. The observed high in vivo repeatability confirms the potential utility of DWI at low-field MR-linacs for early treatment response assessment.

Numerical analysis of heat and moisture transfer in waterproof and breathable composite fabric used for steam protective clothing

A coupled heat and moisture transfer model for waterproof and breathable composite fabrics was developed to examine the behavior of steam heat transfer in porous and hygroscopic membranes. The model accounted for the impact jet flow at outer boundary of fabric, Darcian flow, molecular diffusion, dynamical absorption and phase change of moisture in the fabric. The predictive model was validated by experimental data of hot steam exposure. The heat and moisture distribution in porous and hygroscopic membranes (PM and HM) fabrics was analyzed. The parameters affecting the steam protective performance of waterproof and breathable composite fabric were investigated. The results demonstrated that the HM fabric provided higher steam protective performance than the PM fabric, and placing the membrane on the outer layer of PM and HM fabrics significantly enhanced the steam protective performance. For the PM fabric, the steam protective performance was greatly determined by the thickness and porosity of membrane layer. However, the steam protective performance for the HM fabric was strongly affected by the thickness and thermal conductivity of the substrate layer. The findings obtained in this study can be used to engineer protective clothing that offer better protection against hot steam exposure.

Role of microstructure in the exploitation of self-healing potential in form-stable composite phase change materials based on immiscible alloys

Metallic Phase Change Materials (PCMs), based on solid-liquid transitions, represents one of the most promising technologies for efficient Thermal Energy Storage (TES), due to their superior thermal conductivity and energy storability per unit volume, but suffer of limited solutions for their handling at the molten state. The use of Miscibility Gap Alloys (MGAs) allows to manage PCM volume expansion and keep it confined when molten, preventing interaction with the environment. A relevant example is provided by the Al-Sn system, where Al covers the role of the high-temperature stable and highly thermal-conductive passive matrix and Sn the active PCM. The alloy can thus be considered a Composite PCM (C-PCM). The response fastness of these systems depends on their thermal diffusivity, subjected to abrupt variations under the presence of discontinuities and damages. In this sense, the authors investigated the possibility to employ molten Sn mobility in a potentially damaged C-PCM for self-healing purposes, aimed to restore, at least partially, the material continuity and thus its thermal diffusivity. Exudation heat treatments above the melting temperature of Sn were performed on sets of Al-40%wt. Sn metallic composites, produced either with powder metallurgy or liquid metal routes, in order to quantify and assess the mobility of the Sn under simulated operating conditions. Exudation tests assess Simple Mixed powders and liquid metal routes sample as the ones with the highest healing potential. Al dissolution and re-deposition was established by EDS analyses as one of the principal Sn mobility mechanisms. Laser Flash Analysis tests, as well as microstructural investigations, were performed on the samples before and after both healing-focused and simulated service heat treatments to evaluate the changes of thermal diffusivity. Healing-focused treatment at 250°C for 1 hour generally displayed a moderate thermal diffusivity recovery and simulated service by shorter cycles between 170°C and 270°C slightly reduce it. The beneficial role of healing focused heat treatments at 250°C for 1 hour suggests that the presence of fully molten Sn phase during service for relatively long time could be beneficial for functional healing. The requirements of suitable Al-Sn microstructures for self-healing purposes, granting at the same time the C-PCM functionalities, i.e., thermal energy storage and form-stability, were set.

Regulating smoking in Japan: from manners to rules

Abstract Opinions vary in Japan on whether smoking is deviant today, but the behavior, once widely accepted, faces increasing regulation. Recent reforms, moving beyond reliance on nonsmokers' tolerance and smokers' etiquette, impose stricter and more detailed rules on smoking, along with penalties for noncompliance. As the Japanese government's promotional materials note, the reforms move “from manners to rules” (manā kara rūru e). The evolution of Japan's smoking regulations exemplifies a shift toward more legalistic modes of social control. Historically, Japanese governance relied on non-binding “soft law,” administrative guidance, and societal cooperation. Legalistic governance, in contrast, hinges on formal rules and proceduralized enforcement mechanisms. This article, drawing on twenty-eight interviews and qualitative analysis of policy deliberations, advocacy organization documents, court rulings, and Japanese news coverage, traces how societal actors contributed to this legalistic turn. Tobacco control advocates filed lawsuits, pursued voluntary changes through local activities, and provided information subsidies to policymakers while lobbying for local and national reforms. They thereby helped de-normalize smoking and render it regulatable. By uncovering bottom-up drivers of legalistic governance and the strategies through which societal actors influence regulatory style, this paper contributes to scholarship on governance, policy diffusion, and law and social change.

Single-molecular diffusivity and long jumps of large organic molecules: CoPc on Ag(100).

Energy dissipation and the transfer rate of adsorbed molecules do not only determine the rates of chemical reactions but are also a key factor that often dictates the growth of organic thin films. Here, we present a study of the surface dynamical motion of cobalt phthalocyanine (CoPc) on Ag(100) in reciprocal space based on the helium spin-echo technique in comparison with previous scanning tunnelling microscopy studies. It is found that the activation energy for lateral diffusion changes from 150meV at 45-50K to ≈100meV at 250-350K, and that the process goes from exclusively single jumps at low temperatures to predominantly long jumps at high temperatures. We thus illustrate that while the general diffusion mechanism remains similar, upon comparing the diffusion process over widely divergent time scales, indeed different jump distributions and a decrease of the effective diffusion barrier are found. Hence a precise molecular-level understanding of dynamical processes and thin film formation requires following the dynamics over the entire temperature scale relevant to the process. Furthermore, we determine the diffusion coefficient and the atomic-scale friction of CoPc and establish that the molecular motion on Ag(100) corresponds to a low friction scenario as a consequence of the additional molecular degrees of freedom.

Effects of exposition to glycol ethers on heart rate recovery, parasympathetic modulation and oxygen diffusion at rest and during exercise

Introduction Daily exposition to ether glycols is common. Caretakers using cleaning products are critically exposed by combining physical activity with exposition to highly concentrated products. Previous animal studies showed hemato-, respiratory and autonomic nervous system toxicity amongst others. Yet, no controlled study explored the combination of an exposition to glycol ethers with physical activity in humans. Methods 30 young healthy participants were exposed a control condition (ambient air) and to one of three vaporized glycol ethers: propylene glycol n-propyl ether (PGPE, 25 ppm, n = 10) or propylene glycol ethyl ether (PGEE, 35 ppm, n = 10) or propylene glycol monomethyl ether (PGME, 35 ppm, n = 10) in a single-blind cross-over design. They performed an orthostatic test (5-min supine, 5-min standing) and a 6-min steady-state exercise at 1.5 W/kg followed by 10-min recovery in PGPE/PGEE conditions. In addition, an incremental exercise to exhaustion followed in PGME condition. Heart rate variability (HRV) was measured throughout the protocol, Heart rate recovery (HRR) was assessed during the 10-min recovery post steady-state exercise. Root-mean-square of the successive differences (RMSSD), power spectrum of the low- (LF) and high-frequency (HF) bands, tau, amplitude and T30 were computed for HRR. Near Infrared spectroscopy (NIRS) and cardiac output (using thoracic impedance) were measured for PGME exposition. PO2, PCO2 and pH were measured regularly via arterialized and venous blood sampling. Results Resting values of supine LF (1,180 ± 851 vs. 2,993 ± 2,259 ms2) and standing RMSSD (32 ± 17 vs. 41 ± 17 ms) increased under PGEE. Supine and standing HR decreased under PGPE (65.5 ± 4.8 vs. 61.3 ± 6.9 and 83.8 ± 7.0 vs. 76.1 ± 10.0 bpm) whereas standing RMSSD (26.6 ± 10.0 vs. 37.0 ± 14.9 ms) and LF (825 ± 474 vs. 2,028 ± 1,471 ms2) increased.  Parasympathetic reactivation (e.g., RMSSD, LF and HF) was increased post-exercise under exposition to all three glycol ethers. In addition, amplitude significantly increased when exposed to PGEE. However, unexpectedly, HRR was neither slowed nor speeded. Finally, no differences were observed in any NIRS variables or cardiac output. Accordingly, the modelled muscle oxygen diffusion coefficient was not modified between any solvent conditions. Arterialized blood pH (7.35 ± .06 vs. 7.39 ± .04) and PaCO2 (34.1 ± 5.0 vs. 35.7 ± 4.3 mmHg) increased whilst PaO2 (81.8 ± 9.7 vs. 77.9 ± 10.6 mmHg) decreased. Discussion/Conclusion: The decrease in supine/standing HR associated with a general increase in HRV during recovery likely indicate an increase in parasympathetic modulation, which is compatible with the sedative effects of glycol ethers previously described in animal models. However, HR recovery was not altered. Despite no change in the O2 diffusion coefficient, there was an increase in PaCO2, a decrease in PaO2 and an increase in blood pH, all indicative of potential impaired blood oxygenation during exercise, to be further investigated. To conclude, exposition to different glycol ethers induced an enhanced parasympathetic activation without any changes in HR recovery or O2 diffusion.

Ultrastructural changes of lung tissue under conditions of experimental obesity and smoking.

Obesity can cause respiratory disorders inflicted by adipose tissue accumulation and the numerous cytokines adipocytes produce. Smoking is, first of all, associated with a wide range of lung diseases characterized by diffuse changes in the lung tissue and a decrease in the respiratory volume of the lungs. The study aimed to investigate the ultrastructural changes in the lungs of sexually mature male rats under conditions of experimental obesity and smoking. The total sample of experimental animals consisted of 120 rats, divided into four groups: the control group (n=30) - conditionally healthy rats fed on a standard diet; a group of rats subjected to isolated exposure to tobacco smoke (n=30); a group of experimentally obese rats (n=30) and a group of experimentally obese rats simultaneously exposed to tobacco smoke (n=30) - feeding using a high-fat diet with exposure to a chamber with tobacco smoke. The revealed ultrastructural features of the lungs in the group of rats with experimental obesity and the group of rats with experimental obesity that were simultaneously exposed to tobacco smoke did not differ qualitatively, which indicates that pathological changes in the ultrastructure of the lung tissue developed regardless of the presence or absence of a direct damaging effect on the lung tissue of passive smoking.

Abstract WP219: Diffusion Weighted Imaging Characteristics in Deep White and Gray Matter Structures in Pediatric Patients With Moyamoya Disease

Background: Moyamoya Disease (MMD) is a steno-occlusive arteriopathy associated with transient ischemic attacks, stroke, and cognitive impairments. In adult MMD, normal-appearing deep gray and white matter structures (NADWM) show diffusion changes that are associated with cognitive impairments. Apparent diffusion coefficient [ADC] measures the mean diffusion and is sensitive to these changes. The association of ADC changes in NADWM in pediatric MMD is not clear. Our objective is to determine whether ADC is elevated in NADWM in pediatric MMD patients. Hypothesis: ADC values in NADWM will be elevated in MMD patients compared to controls. Methods: Twenty-nine MMD patients and no stroke and 7 healthy controls (HC) were included in a single center, retrospective study. Diffusion and T1-weighted images were analyzed. We constructed a script implementing a convolutional neural network (CNN) based approach to segment and binarize cortical regions of interest (ROI) and allow extraction of ADC values (units =[x10 -6 mm 2 /s]). Segmented ROIs included: 1) all white matter (WM), and NADWM including: 2) thalamus, 3) caudate, 4) putamen, 5) globus pallidus, 6) hippocampus. Mean ADC values were compared for: 1) all ROIs between MMD and controls, and 2) all ROIs in the MMD affected and the contralateral hemispheres within the MMD group. Results: Patients were on average 7.7 + 5.4 years at MMD diagnosis. In all WM, MMD patients had significantly higher ADC values than controls in the left (mean= 865.7 + 101.6 versus 762.4 + 21.6, p=0.01) and right hemispheres (mean= 869.9 + 104.9 versus 761.0 + 21.3, p=.01), respectively. In NADGM, there were no significant differences found between the MMD and control groups in any of the NADGM ROIs. In the NADGM of MMD patients, higher ADC values were found in the putamen (mean= 778.2 + 46.0, p=0.041), hippocampus (mean=1009.5 + 58.6, p=0.005) and all NAWM (mean= 860.3 + 57.0, p&lt;0.0001) in the MMD affected compared to the contra-lesional hemisphere. Conclusions: In pediatric patients with MMD, we found elevated ADC values in deep gray and white matter structures in the diseased hemisphere indicating alterations in the underlying microstructure. Our future analysis will integrate hemodynamic profiles and cognitive outcomes.

[Correlation between postoperative microstructural changes in cerebral white matter and early postoperative cognitive function in patients undergoing meningioma resection].

Objective: To analyze the correlation between microstructure changes in cerebral white matter before and after surgery and early postoperative cognitive function in patients undergoing meningioma resection. Methods: A total of 17 patients who underwent their first meningioma resection at Xuanwu Hospital of Capital Medical University from April 2022 to April 2023 were prospectively included as observation group, with 5 males and 12 females, aged (56.4±7.3) years. Another 15 age- and education-matched patients with cerebral benign tumor were recruited as control group during the same period, with 5 males and 10 females, aged (55.2±8.0) years. Neuropsychological tests (NST), mainly including auditory verbal learning test of Huashan version (AVLT-H), the Montreal cognitive assessment-basic (MoCA-B), clock drawing task-30 (CDT-30), shape trails test-B (STT-B) and animal fluence test (AFT), were conducted at 1 day before surgery, 1 day and within 3-4 days after surgery in the observation group. Simultaneously, magnetic resonance imaging (MRI) scans were performed to collect diffusion tensor imaging (DTI) images at 1 day before surgery and within 3-4 days after surgery. The same NST were conducted at 1 day, 3 days and 6 days after admission in the control group to adjust for learning effects from repeated tests. The microstructure changes of the whole brain white matter were evaluated at the group level by using tract-based spatial statistics (TBSS) technology, including changes of fractional anisotropy (FA), mean diffusion (MD), axial diffusion (AD), and radial diffusion (RD). Then, correlation was performed between DTI indicators with statistically significant and cognitive function. Results: After adjusting for the learning effects, the AVLT-H (R), MoCA-B, and CDT-30 scores decreased, and the evaluation time of STT-B prolonged after surgery in patients with meningioma. And their perioperative decreased values were -0.78 (95%CI:-3.28--0.28) points, -2.22 (95%CI:-4.22--0.72) points, -2.74 (95%CI:-5.29--0.19) points, and 61.49 (95%CI: 5.71-117.27) seconds, respectively, with statistically significant differences (all P<0.05). Group level analysis of TBSS based on DTI images showed decreased FA mainly in the right superior cerebellar peduncle, left posterior limb of internal capsule and genu of corpus callosum, and increased RD mainly in the left anterior corona radiata in patients undergoing meningioma resection, with statistically significant differences (all PFWE<0.05). Linear correlation showed that the perioperative decreased values of FA in genu of corpus callosum and right superior cerebellar peduncle were positively correlated with the perioperative decreased values of AVLT-H (L) after adjusting for learning effects (r=0.72, 0.52, all PFWE<0.05). Conclusions: Patients undergoing meningioma resection are at risk of postoperative cognitive decline. Perioperative decreased values of FA in genu of corpus callosum and right superior cerebellar peduncle based on DTI images are positively correlated with the perioperative decreased values of AVLT-H (L) after adjusting for learning effects.

Lethal case of lung gangrene against the background of viral-bacterial pneumonia (COVID-19 and &lt;i&gt;Fusobacteria&lt;/i&gt;)

The respiratory system is the main target of COVID-19 infection spread by the SARS-CoV-2 virus. This study presents a case of viral–bacterial pneumonia caused by SARS-CoV-2 and Fusobacteria complicated by the development of gangrene in the lower lobe of the right lung with abscess formation. Accompanied by an ambulance team for emergency reasons, the patient was admitted for inpatient treatment with complaints of pain when coughing, dyspnea, cough with mucopurulent sputum, and fever up to 39.6°С. Chest computed tomography revealed signs of viral–bacterial pneumonia. Infiltration was determined in the lower lobe of the right lung, against which a cavity with melting lung tissue was observed. A virological test of throat and nasal swabs detected SARS-CoV-2 coronavirus RNA. Despite treatment, the patient died. Autopsy revealed signs of viral–bacterial pneumonia, a decaying cavity with purulent content, and diffuse destructive changes with hemorrhages. The cause of death of the patient was COVID-19, which caused bilateral viral–bacterial pneumonia complicated by the development of gangrene in the lower lobe of the right lung with abscess formation.