Fresh Brain Research Articles

Rapid digital pathology of H&E-stained fresh human brain specimens as an alternative to frozen biopsy

BackgroundHematoxylin and Eosin (H&E)-based frozen section (FS) pathology is presently the global standard for intraoperative tumor assessment (ITA). Preparation of frozen section is labor intensive, which might consume up-to 30 minutes, and is susceptible to freezing artifacts. An FS-alternative technique is thus necessary, which is sectioning-free, artifact-free, fast, accurate, and reliably deployable without machine learning and/or additional interpretation training.MethodsWe develop a training-free true-H&E Rapid Fresh digital-Pathology (the-RFP) technique which is 4 times faster than the conventional preparation of frozen sections. The-RFP is assisted by a mesoscale Nonlinear Optical Gigascope (mNLOG) platform with a streamlined rapid artifact-compensated 2D large-field mosaic-stitching (rac2D-LMS) approach. A sub-6-minute True-H&E Rapid whole-mount-Soft-Tissue Staining (the-RSTS) protocol is introduced for soft/frangible fresh brain specimens. The mNLOG platform utilizes third harmonic generation (THG) and two-photon excitation fluorescence (TPEF) signals from H and E dyes, respectively, to yield the-RFP images.ResultsWe demonstrate the-RFP technique on fresh excised human brain specimens. The-RFP enables optically-sectioned high-resolution 2D scanning and digital display of a 1 cm2 area in <120 seconds with 3.6 Gigapixels at a sustained effective throughput of >700 M bits/sec, with zero post-acquisition data/image processing. Training-free blind tests considering 50 normal and tumor-specific brain specimens obtained from 8 participants reveal 100% match to the respective formalin-fixed paraffin-embedded (FFPE)-biopsy outcomes.ConclusionsWe provide a digital ITA solution: the-RFP, which is potentially a fast and reliable alternative to FS-pathology. With H&E-compatibility, the-RFP eliminates color- and morphology-specific additional interpretation training for a pathologist, and the-RFP-assessed specimen can reliably undergo FFPE-biopsy confirmation.

Mechanisms of mechanical load transfer through brain tissue

Brain injuries are often characterized by diffusely distributed axonal and vascular damage invisible to medical imaging techniques. The spatial distribution of mechanical stresses and strains plays an important role, but is not sufficient to explain the diffuse distribution of brain lesions. It remains unclear how forces are transferred from the organ to the cell scale and why some cells are damaged while neighboring cells remain unaffected. To address this knowledge gap, we subjected histologically stained fresh human and porcine brain tissue specimens to compressive loading and simultaneously tracked cell and blood vessel displacements. Our experiments reveal different mechanisms of load transfer from the organ or tissue scale to single cells, axons, and blood vessels. Our results show that cell displacement fields are inhomogeneous at the interface between gray and white matter and in the vicinity of blood vessels—locally inducing significant deformations of individual cells. These insights have important implications to better understand injury mechanisms and highlight the importance of blood vessels for the local deformation of the brain’s cellular structure during loading.

Effects of formalin fixation on polarimetric properties of brain tissue: fresh or fixed?

Imaging Mueller polarimetry (IMP) appears as a promising technique for real-time delineation of healthy and neoplastic tissue during neurosurgery. The training of machine learning algorithms used for the image post-processing requires large data sets typically derived from the measurements of formalin-fixed brain sections. However, the success of the transfer of such algorithms from fixed to fresh brain tissue depends on the degree of alterations of polarimetric properties induced by formalin fixation (FF). Comprehensive studies were performed on the FF induced changes in fresh pig brain tissue polarimetric properties. Polarimetric properties of pig brain were assessed in 30 coronal thick sections before and after FF using a wide-field IMP system. The width of the uncertainty region between gray and white matter was also estimated. The depolarization increased by 5% in gray matter and remained constant in white matter following FF, whereas the linear retardance decreased by 27% in gray matter and by 28% in white matter after FF. The visual contrast between gray and white matter and fiber tracking remained preserved after FF. Tissue shrinkage induced by FF did not have a significant effect on the uncertainty region width. Similar polarimetric properties were observed in both fresh and fixed brain tissues, indicating a high potential for transfer learning.

The in-tissue molecular architecture of β-amyloid pathology in the mammalian brain

Amyloid plaques composed of Aβ fibrils are a hallmark of Alzheimer’s disease (AD). However, the molecular architecture of amyloid plaques in the context of fresh mammalian brain tissue is unknown. Here, using cryogenic correlated light and electron tomography we report the in situ molecular architecture of Aβ fibrils in the AppNL-G-F familial AD mouse model containing the Arctic mutation and an atomic model of ex vivo purified Arctic Aβ fibrils. We show that in-tissue Aβ fibrils are arranged in a lattice or parallel bundles, and are interdigitated by subcellular compartments, extracellular vesicles, extracellular droplets and extracellular multilamellar bodies. The Arctic Aβ fibril differs significantly from an earlier AppNL-F fibril structure, indicating a striking effect of the Arctic mutation. These structural data also revealed an ensemble of additional fibrillar species, including thin protofilament-like rods and branched fibrils. Together, these results provide a structural model for the dense network architecture that characterises β-amyloid plaque pathology.

An anatomical and volumetric study on brain ventricles in sheep using different techniques.

This study investigated the morphological features of the ventricular system of the brain in Akkaraman sheep in a measured and structural manner. In the study, 24 adults male Akkaraman sheep, which is a common and hornless breed were used. Anatomical features of the ventricular system were determined by latex injection and dissection, acrylic injection and corrosion cast and magnetic resonance imaging. In the measurements, a precise digital calliper, Archimedes' principle, Cavalieri's principle and ITK-SNAP imaging were used by comparing them with each other. The average weight of fresh sheep brains was 102 g (0.226 lb), the volume 115.8 mL and the length, height and width were 130.78, 40.58 and 70.08 mm, respectively. The olfactoric bulb contained a cavity associated with the lateral ventricle, large enough to be called a ventricle. The cavity of septum pellucidum has a large cavity was observed. However, there was no cerebrospinal fluid in this cavity. The interventricular foramen of the dissected brain was also an opening measuring 1.4 mm × 3.9 mm × 5.5 mm. The total volume of the ventricles of the brain of Akkaraman sheep was found to be 7107.71 ± 479, 7115 ± 737 and 7080 ± 647 mm3 and 6200 mm3 using the Planimetry, Point Counting method, ITK-SNAP program, and Archimedes' principle, respectively. In the study, species and breed-specific brain indices values and many detailed morphometric data were obtained.

Robustness of the wide-field imaging Mueller polarimetry for brain tissue differentiation and white matter fiber tract identification in a surgery-like environment: an ex vivo study.

During neurooncological surgery, the visual differentiation of healthy and diseased tissue is often challenging. Wide-field imaging Muller polarimetry (IMP) is a promising technique for tissue discrimination and in-plane brain fiber tracking in an interventional setup. However, the intraoperative implementation of IMP requires realizing imaging in the presence of remanent blood, and complex surface topography resulting from the use of an ultrasonic cavitation device. We report on the impact of both factors on the quality of polarimetric images of the surgical resection cavities reproduced in fresh animal cadaveric brains. The robustness of IMP is observed under adverse experimental conditions, suggesting a feasible translation of IMP for in vivo neurosurgical applications.

HDL and LDL have distinct, opposing effects on LPS-induced brain inflammation

Endotoxemia and sepsis induce neuroinflammation and increase the risk of neurodegenerative disorders although the mechanism by which peripheral infection leads to brain inflammation is not well understood. While circulating serum lipoproteins are known immunometabolites with the potential to modulate the acute phase response and cross the blood brain barrier, their contribution to neuroinflammation during systemic infection is unknown. The objective of this study was to elucidate the mechanisms by which lipoprotein subclasses modulate lipopolysaccharide (LPS)-induced neuroinflammation. Adult C57BL/6 mice were divided into 6 treatment groups, including a sterile saline vehicle control group (n = 9), an LPS group (n = 11), a premixed LPS + HDL group (n = 6), a premixed LPS + LDL group (n = 5), a HDL only group (n = 6) and an LDL only group (n = 3). In all cases injections were administered intraperitoneally. LPS was administered at 0.5 mg/kg, and lipoproteins were administered at 20 mg/kg. Behavioural testing and tissue collection was performed 6 h post-injection. The magnitude of peripheral and central inflammation was determined by qPCR of pro-inflammatory genes in fresh liver and brain. Metabolite profiles of liver, plasma and brain were determined by 1H NMR. Endotoxin concentration in the brain was measured by the Limulus Amoebocyte Lysate (LAL) assay. Co-administration of LPS + HDL exacerbated both peripheral and central inflammation, whilst LPS + LDL attenuated this inflammation. Metabolomic analysis identified several metabolites significantly associated with LPS-induced inflammation, which were partially rescued by LDL, but not HDL. Endotoxin was detected at significantly greater concentrations in the brains of animals that received LPS + HDL compared to LPS + saline, but not those that received LPS + LDL. These results suggest that HDL may promote neuroinflammation through direct shuttling of endotoxin to the brain. In contrast, LDL was shown to have anti-neuroinflammatory properties in this study. Our results indicate that lipoproteins may be useful targets in neuroinflammation and neurodegeneration associated with endotoxemia and sepsis.

Abstract 5105: TIMP1 mediates astrocyte-dependent local immunosuppression in brain metastasis

Abstract Brain metastasis is an unmet clinical need, affecting between 10-30% of cancer patients with 200000 to 400000 newly diagnosis per annum in the US. Recently, several clinical trials have reported benefits using immunotherapy to treat brain metastasis. However, variability of the responses is broad and high benefit is found mainly in asymptomatic brain metastasis, while the benefit is dramatically reduced in the clinically relevant stage. Thus, it is currently unknown how to effectively target symptomatic brain metastases with immunotherapy. We previously reported a clinically relevant protumoral program driven by STAT3 activation in a subpopulation of reactive astrocytes in these advanced stages of the disease. Our current study further exploited the heterogeneity within the metastasis-associated microenvironment as a resource to identify novel therapeutic vulnerabilities to improve the benefits of immunotherapies based on immune checkpoint blocking antibodies (ICB) in symptomatic brain metastasis. Our results demonstrate that reactive astrocytes are strong immunomodulatory cells in brain tumors. We have identified the molecular profile of disease-associated glial cells and defined its connection to modulatory activities on specific lymphocyte populations in experimental brain metastasis as well as human-derived samples. scRNASeq and high content multiplex immunofluorescence allowed us to report a novel local immunomodulatory axis dependent on TIMP1 (astrocytes)/CD63 (CD8 T cells), which is present in brain metastasis patients with high immunoscore and would imply an additional immunosuppressive signal for potential ICB responders in brain metastasis. Genetic and pharmacologic approaches targeting this STAT3-dependent local immunomodulatory axis have allowed us to define the rationale to combine immune checkpoint blockade with a STAT3 inhibitor, which we previously used in patients. We proved that such combined immunotherapy boost the systemic activation of T cells while also preventing the local blockade. Additionally, our comprehensive strategy includes the possibility to stratify patients that are best qualified to benefit from this therapy by measuring TIMP1 in liquid biopsies from CSF. Even more, our data using Patient Derived Organotypic Cultures (PDOC) from fresh brain metastasis neurosurgeries confirms that our therapeutic strategy might benefit brain metastases generated from any primary source. In conclusion, we describe an immunosuppressive mechanism in the brain microenvironment that could explain the lack of response to ICB in patients with advanced brain metastasis. Our finding provides the rationale to implement complementary approaches targeting local immunosuppression to increase the benefit of immunotherapy in symptomatic brain metastasis. Citation Format: Neibla Priego, Pedro García-Gómez, Ana de Pablos-Aragoneses, María Perea-García, Laura Álvaro-Espinosa, Carolina Hernández-Oliver, Elena Martínez-Saez, Ángel Pérez-Núñez, Aurelio Hernández-Laín, Rebeca Sanz-Pamplona, Marc Schmitz, Stephen J. Crocker, Diego Serrano, Asís Palazón, RENACER Red Nacional de Metástasis Cerebral, Manuel Valiente. TIMP1 mediates astrocyte-dependent local immunosuppression in brain metastasis. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5105.

α-MSH-catabolic enzyme prolylcarboxypeptidase in nucleus accumbens shell ameliorates stress susceptibility in mice through regulating synaptic plasticity.

Emerging evidence demonstrates the vital role of synaptic transmission and structural remodeling in major depressive disorder. Activation of melanocortin receptors facilitates stress-induced emotional behavior. Prolylcarboxypeptidase (PRCP) is a serine protease, which splits the C-terminal amino acid of α-MSH and inactivates it. In this study, we asked whether PRCP, the endogenous enzyme of melanocortin system, might play a role in stress susceptibility via regulating synaptic adaptations. Mice were subjected to chronic social defeat stress (CSDS) or subthreshold social defeat stress (SSDS). Depressive-like behavior was assessed in SIT, SPT, TST and FST. Based on to behavioral assessments, mice were divided into the susceptible (SUS) and resilient (RES) groups. After social defeat stress, drug infusion or viral expression and behavioral tests, morphological and electrophysiological analysis were conducted in PFX-fixed and fresh brain slices containing the nucleus accumbens shell (NAcsh). We showed that PRCP was downregulated in NAcsh of susceptible mice. Administration of fluoxetine (20 mg·kg-1·d-1, i.p., for 2 weeks) ameliorated the depressive-like behavior, and restored the expression levels of PRCP in NAcsh of susceptible mice. Pharmacological or genetic inhibition of PRCP in NAcsh by microinjection of N-benzyloxycarbonyl-L-prolyl-L-prolinal (ZPP) or LV-shPRCP enhanced the excitatory synaptic transmission in NAcsh, facilitating stress susceptibility via central melanocortin receptors. On the contrary, overexpression of PRCP in NAcsh by microinjection of AAV-PRCP alleviated the depressive-like behavior and reversed the enhanced excitatory synaptic transmission, abnormal dendritogenesis and spinogenesis in NAcsh induced by chronic stress. Furthermore, chronic stress increased the level of CaMKIIα, a kinase closely related to synaptic plasticity, in NAcsh. The elevated level of CaMKIIα was reversed by overexpression of PRCP in NAcsh. Pharmacological inhibition of CaMKIIα in NAcsh alleviated stress susceptibility induced by PRCP knockdown. This study has revealed the essential role of PRCP in relieving stress susceptibility through melanocortin signaling-mediated synaptic plasticity in NAcsh.

Abstract TMP109: Labeling And Isolating Cell Specific Neuronal Mitochondria And Their Functional Analysis In Mice Post Stroke

Introduction: In vivo neuronal mitochondria dysfunction post stroke has not been well investigated. Methods: Using Mito-tag mice in combine with local infection of AAV9 produced from plasmids carrying Cre-recombinase controlled by neuronal promoters, we generated reporter mice expressing a hemagglutinin (HA)-tagged EGFP that localizes to mitochondrial outer membranes in synaptophysin (SYN) and calmodulin-kinase II (CaMKII) glutamatergic neurons localized to cerebral cortex. These mice were subjected to permanent middle cerebral artery occlusion and sacrificed 14 days post stroke. Fresh brain tissues were excised from the ischemic core (IC), ischemic boundary zone (IBZ) as well as from the homologous contralateral hemisphere, and the crude mitochondrial fractions (CMF) were extracted. Neuronal mitochondria were then isolated from the CMF by anti-HA magnetic beads (Thermo Scientific) and their specificity and oxidative phosphorylation (OXPHOS) complexes were confirmed by means of Western-blot. Seahorse assay was employed to measure oxygen consumption rate (OCR) of the isolated mitochondria as an indicator of mitochondrial function. Results: The bead pulled components were co-precipitated with GFP and enriched with mitochondrial markers, e.g. voltage-dependent anion channel, cytochrome C, and COX IV, but lacked the Golgi protein RCAS1 as well as endoplasmic reticulum markers: Heme-oxygenase 1 and Calnexin, indicating that specific neuronal mitochondria have been selectively isolated. Western-blot data showed that OXPHOS components in SYN + and CAMKII + neuronal mitochondria were significantly downregulated in the IBZ and further decreased in the IC compared to the contralateral tissue, which was associated with the significant reductions of mitochondrial function measured by OCR (p&lt;0.05, respectively, for both neuron types). These data suggesting dysfunction of neuronal mitochondria post stroke. Conclusions: We, for the first time, measure mitochondrial function in 2 types of neurons post stroke. By introducing specific neuronal promoter controlled Cre recombinase to Mito-tag mouse, mitochondria from individual neuronal linage cells can be efficiently labeled and isolated to investigate functional change post stroke.

The development of compulsive coping behaviour is associated with a downregulation of Arc in a Locus Coeruleus neuronal ensemble

Some compulsive disorders have been considered to stem from the loss of control over coping strategies, such as displacement. However, the cellular mechanisms involved in the acquisition of coping behaviours and their subsequent compulsive manifestation in vulnerable individuals have not been elucidated. Considering the role of the locus coeruleus (LC) noradrenaline-dependent system in stress and related excessive behaviours, we hypothesised that neuroplastic changes in the LC may be associated with the acquisition of an adjunctive polydipsic water drinking, a prototypical displacement behaviour, and the ensuing development of compulsion in vulnerable individuals. Thus, male Sprague Dawley rats were characterised for their tendency, or not, to develop compulsive polydipsic drinking in a schedule-induced polydipsia (SIP) procedure before their fresh brains were harvested. A new quantification tool for RNAscope assays revealed that the development of compulsive adjunctive behaviour was associated with a low mRNA copy number of the plasticity marker Arc in the LC which appeared to be driven by specific adaptations in an ensemble of tyrosine hydroxylase (TH)+, zif268− neurons. This ensemble was specifically engaged by the expression of compulsive adjunctive behaviour, not by stress, because its functional recruitment was not observed in individuals that no longer had access to the water bottle before sacrifice, while it consistently correlated with the levels of polydipsic water drinking only when it had become compulsive. Together these findings suggest that downregulation of Arc mRNA levels in a population of a TH+/zif268− LC neurons represents a signature of the tendency to develop compulsive coping behaviours.

Eradication of human immunodeficiency virus-1 reservoir in the brain microglia.

Eradication of human immunodeficiency virus-1 reservoir in the brain microglia.

Spectral Optical Properties of Gray Matter in Human Male Brain Tissue Measured at 400–1100 nm

Gray matter, in the outermost layer of the cerebral cortex, plays a significant role in processing important information, such as when reasoning and planning, in addition to influencing intelligence, emotion, memory, and language. In this paper, measurements of the optical properties, such as the attenuation coefficients, scattering coefficients, scattering efficiency, and penetration depth of gray matter in the cerebral cortex were measured in the fresh brain tissue of a healthy human male at a spectral range of 400–1100 nm. Determining the optical properties of gray matter is important for developing NIR noninvasive diagnostic imaging techniques and therapy. The absorption spectra of the gray matter tissues obtained here showed clear peaks at 550 and 580 nm due to HBO2 and 970 nm due to water. The attenuation coefficient, transport length, and penetration depth for the gray matter were measured at 800 nm. The possible NIR optical imaging depth was roughly 3.8 mm, determined by the theoretical limit resulting from ballistic and snake photons. Using Beer’s law and the Mie model, the structural properties, such as the density of neurons, in the gray matter of human brain tissue, were investigated for the first time. The density of neurons in the examined gray matter tissue sample was estimated as roughly 40,000 neurons/mg.

Deep spatial phenotyping of microglial populations and pathological features in Alzheimer’s disease brains using CODEX Multiplexed Imaging

AbstractBackgroundRecent high‐throughput transcriptomics and proteomics analysis have shown a remarkable heterogeneity of microglia phenotypes across various disease conditions. Differently from neurons, microglia appearance can be characterized as a continuum between ramified and amoeboid morphologies. The transcriptional and proteomic profiles associated to each degree of morphology are potentially multiple and dependent on the healthy/pathological conditions in consideration with sex, anatomical area of the brain and disease stage. While single‐cell RNA sequencing (scRNA‐seq) has been instrumental in revealing microglia sub‐populations, it is lacking in spatial information and phenotypic characterization. The scarcity of fresh human brain tissue imposes a bottleneck for RNA‐seq studies, while paraffin‐embedded tissues are widely available in most brain banks. CODEX multiplexed imaging technology permits a deep characterization of microglial cells preserving their morphology and avoiding cell activation by aggressive sample preparation methods as occurs in tissue homogenates. Moreover, we can discriminate the immune cells in brain blood vessel from those in the parenchyma.MethodUsing this technology, we characterize microglia sub‐population localization in relationship to the distance from neurodegenerative disease pathogenic features in post‐mortem AD brain samples and matching controls. Bioinformatics analysis were performed to achieve microglial segmentation to a single‐cell level and cell clustering by protein expression.ResultOur results show the existence of different microglial cells populations, which vary between AD and control brains. Expression of blood‐derived macrophages markers was observed in parenchymal ramified cells close to blood vessels and/or Aβ plaques. We were able to deeply characterize this population and measure their distance to the nearest blood vessel and Aβ plaque. Microglial/macrophages activation markers were increased correlating with the distance to the plaques.ConclusionThis study allowed us to characterize the changes of microglia phenotype in the immediate neighborhood of pathogenic features. Such observation will be instrumental to understanding the role of several Late Onset Alzheimer’s Diseases associated genes and potentially identify novel drug targets.

TRPV1 and GABAB1 in the Cerebrospinal Fluid-Contacting Nucleus are Jointly Involved in Chronic Inflammatory Pain in Rats.

To assess the receptors of TRPV1 and GABAB1 receptors that were colocalized in cerebrospinal fluid contacting nucleus (CSF-contact nucleus) of chronic inflammatory pain (CIP) rats bringing inspiration for reducing chronic pain. A rat model of CIP was constructed by plantar injection of complete Freund's adjuvant (CFA), and the paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured 1, 3, 5, 7, 10, and 14 days after plantar injection. In the first part of the experiment, rats with CIP were divided into the immunofluorescence group and the coimmunoprecipitation (Co-IP) group (n = 6). Rats in the immunofluorescence group were injected with the retrograde tracer CB conjugated with Alexa Fluor 594 into the lateral ventricle two days before the injection of CFA into the plantar surface of the left paw. Three days later, rats that exhibited hyperalgesia were perfused, and their brains were extracted and used for double immunofluorescence staining of the CSF-contacting nucleus. Rats in the Co-IP group were anesthetized and dissected 3 days after CFA injection, and fresh brain segments containing the CSF-contacting nucleus were collected for Co-IP to assess the colocalization of TRPV1 and GABAB1 in the CSF-contacting nucleus (n = 6). In the second part of the experiment, SD rats were divided into the normal saline group (control group) and the CFA group. Fresh CSF-contacting nucleus-containing tissues were collected for Western blot analysis 3 days after plantar injection to observe the changes in TRPV1 and GABAB1 expression in the CSF-contacting nucleus. TRPV1 and GABAB1 were co-expressed in the CSF-contacting nucleus in rats with CIP, and their expression was upregulated. TRPV1 and GABAB1 in the CSF-contacting nucleus are jointly involved in CIP in rats, and there is a direct or indirect link between TRPV1 and GABAB1.

Impact of preprocessing methods on the Raman spectra of brain tissue.

Delineating cancer tissue while leaving functional tissue intact is crucial in brain tumor resection. Despite several available aids, surgeons are limited by preoperative or subjective tools. Raman spectroscopy is a label-free optical technique with promising indications for tumor tissue identification. To allow direct comparisons between measurements preprocessing of the Raman signal is required. There are many recognized methods for preprocessing Raman spectra; however, there is no universal standard. In this paper, six different preprocessing methods were tested on Raman spectra (n > 900) from fresh brain tissue samples (n = 34). The sample cohort included both primary brain tumors, such as adult-type diffuse gliomas and meningiomas, as well as metastases of breast cancer. Each tissue sample was classified according to the CNS WHO 2021 guidelines. The six methods include both direct and iterative polynomial fitting, mathematical morphology, signal derivative, commercial software, and a neural network. Data exploration was performed using principal component analysis, t-distributed stochastic neighbor embedding, and k-means clustering. For each of the six methods, the parameter combination that explained the most variance in the data, i.e., resulting in the highest Gap-statistic, was chosen and compared to the other five methods. Depending on the preprocessing method, the resulting clusters varied in number, size, and associated spectral features. The detected features were associated with hemoglobin, neuroglobin, carotenoid, water, and protoporphyrin, as well as proteins and lipids. However, the spectral features seen in the Raman spectra could not be unambiguously assigned to tissue labels, regardless of preprocessing method. We have illustrated that depending on the chosen preprocessing method, the spectral appearance of Raman features from brain tumor tissue can change. Therefore, we argue both for caution in comparing spectral features from different Raman studies, as well as the importance of transparency of methodology and implementation of the preprocessing. As discussed in this study, Raman spectroscopy for in vivo guidance in neurosurgery requires fast and adaptive preprocessing. On this basis, a pre-trained neural network appears to be a promising approach for the operating room.

Anatomical study of circle of Willis on fresh autopsied brains. A study of a Romanian population.

Because the circle of Willis (CoW) supplies blood to the brain in case of occlusion of one of the cerebral arteries, identification of any change in its classical shape could be useful in the assessment of cerebrovascular morbidity. The purpose of our research was to study the anatomical variants of CoW identified on fresh brains obtained at the clinical autopsies of adult deceased patients belonging to a specific population (Northeastern region of Romania), as no data are available for Romania population up to date. The study group included consecutive patients who died in Prof. Dr. Nicolae Oblu Emergency Clinical Hospital, Iaşi, Romania, due to medical causes between January 1, 2014 and June 30, 2016, to whom a clinical autopsy was performed. From a total of 96 circles of Willis, 29.17% presented an atypical morphology. We identified eight types of anatomical variants, which affected simultaneously both the posterior and the anterior parts of CoW in 46.42% of cases. The most frequent anatomical variants were hypoplasia (20.91%), followed by the absence of an artery (3.06%), and partially fetal type artery (2.04%). 67.86% of atypical CoW exhibited more than one anatomical variant of an artery in one circle. We identified nine of the 23 morphological patterns that were published to date, and also nine new types. Our research proved that in the population living in the Northeastern part of Romania the anatomical variations of circles of Willis are very polymorphic, with particular morphological aspects.

Feasibility of ultrashort echo time quantitative susceptibility mapping with a 3D cones trajectory in the human brain.

Quantitative susceptibility mapping (QSM) has surfaced as a promising non-invasive quantitative biomarker that provides information about tissue composition and microenvironment. Recently, ultrashort echo time quantitative susceptibility mapping (UTE-QSM) has been investigated to achieve QSM of short T2 tissues. As the feasibility of UTE-QSM has not been demonstrated in the brain, the goal of this study was to develop a UTE-QSM with an efficient 3D cones trajectory and validate it in the human brain. An ultrashort echo time (UTE) cones sequence was implemented in a 3T clinical MRI scanner. Six images were acquired within a single acquisition, including UTE and gradient recalled echo (GRE) images. To achieve QSM, a morphology-enabled dipole inversion (MEDI) algorithm was incorporated, which utilizes both magnitude and phase images. Three fresh cadaveric human brains were scanned using the 3D cones trajectory with eight stretching factors (SFs) ranging from 1.0 to 1.7. In addition, five healthy volunteers were recruited and underwent UTE-QSM to demonstrate the feasibility in vivo. The acquired data were processed with the MEDI-QSM pipeline. The susceptibility maps estimated by UTE-QSM showed reliable tissue contrast. In the ex vivo experiment, high correlations were found between the baseline (SF of 1.0) and SFs from 1.1 to 1.7 with Pearson's correlations of 0.9983, 0.9968, 0.9959, 0.9960, 0.9954, 0.9943, and 0.9879, respectively (all p-values < 0.05). In the in vivo experiment, the measured QSM values in cortical gray matter, juxtacortical white matter, corpus callosum, caudate, and putamen were 25.4 ± 4.0, -21.8 ± 3.2, -22.6 ± 10.0, 77.5 ± 18.8, and 53.8 ± 7.1 ppb, consistent with the values reported in the literature. Ultrashort echo time quantitative susceptibility mapping enables direct estimation of the magnetic susceptibility in the brain with a dramatically reduced total scan time by use of a stretched 3D cones trajectory. This technique provides a new biomarker for susceptibility mapping in the in vivo brain.

An Analysis of Khurtsiin Deed-6 Compound’s Effect on IL-1β Expression in Nitroglycerin Induced Migraine and Alcohol Exposed Neurodegeneration Model in Rat

Objectives: To investigate the anti-inflammatory activity of Khurtsiin deed-6 in migraine and neurodegeneration rat models. Methods: This study uses nitroglycerin induced migraine was model and alcohol exposed neurodegeneration model in Wistar rats to evaluate anti-inflammatory effect of Khurtsiin deed-6 at the 3 different doses of 50, 100and 150 mg/kg, orally. After anesthesia, the brains were removed, then trigeminal nucleus caudal is and hippocampus region isolated from fresh brain. And followed by protein and RNA extraction. Interleukin-1β expression was analyzed by real time polymerase chain reaction. Results: Nitroglycerin induced rat migraine model had increased Interleukin-1β expression in brain TNC area (p&lt;0.001). It has been decreased dramatically after treatment of Khurtsiin deed-6 by doses of 50mg/kg, 100mg/kg and 150mg/kg treatment in brain trigeminal nucleus caudal is region (p&lt;0.01) comparing ibuprofen treated group. Moreover alcohol exposed neurodegeneration rat model had observed increased Interleukin-1β expression in brain Hp area (p&lt;0.001). But Khurtsiin deed-6 doses of 50mg/kg, 100mg/kg and 150mg/kg treatment reduced neuroinflammatory cytokines IL1β expression in hippocampus region (p&lt;0.01, p&lt;0.001) of alcoholic rat models comparing pyridoxamine administrated animals. Conclusion: The present finding indicates that Khurtsiin deed-6shows anti-inflammatory activity decreasing the level of Interleukin -1β cytokine in nitroglycerin induced migraine and alcohol exposed neurodegeneration rat models

Time-domain feature extraction for target specificity in photoacoustic remote sensing microscopy.

Photoacoustic remote sensing (PARS) microscopy is an emerging label-free optical absorption imaging modality. PARS operates by capturing nanosecond-scale optical fluctuations produced by photoacoustic pressures. These time-domain (TD) variations are usually projected by amplitude to determine optical absorption magnitude. However, valuable details on a target's material properties (e.g., density, speed of sound) are contained within the TD signals. This work uses a novel, to the best of our knowledge, clustering method to learn TD features, based on signal shape, which relate to underlying material traits. A modified K-means method is used to cluster TD data, capturing representative signal features. These features are then used to form virtual colorizations which may highlight tissues based on their underlying material properties. Applied in fresh resected murine brain tissue, colorized visualizations highlight distinct regions of tissue. This may potentially facilitate differentiation of tissue constituents (e.g., myelinated and unmyelinated axons, cell nuclei) in a single acquisition.