High-resolution Magnetic Resonance Research Articles

Changes in brain structure and related functional connectivity during menstruation in women with primary dysmenorrhea.

Neuroimaging studies have identified altered brain structures and functions in women with primary dysmenorrhea (PDM). However, previous studies focused on either structural or functional changes in specific brain regions rather than combining structural and functional analysis. Therefore, this prospective cross-sectional study aimed to investigate the changes in whole brain structure, and functional variation along with structural abnormalities in women with PDM during menstruation. In all, 31 patients with PDM (PTs) and 31 healthy controls (HCs) were recruited. Voxel-based morphometry (VBM) and surface-based morphometry (SBM) analyses were applied to investigate structural changes based on high-resolution T1-weighted magnetic resonance images. Functional connectivity (FC) analysis was performed to evaluate functional variations related to the brain regions that showed structural group differences. Pearson correlation analysis was performed to assess the relationship between neuroimaging changes and clinical measures. Compared to HCs, PTs had reduced gray matter volume (GMV) in the right superior temporal gyrus (STG) and reduced thickness in the bilateral orbitofrontal cortex (OFC), left postcentral gyrus (PoCG), and left superior occipital gyrus (SOG). Among these areas, the STG and PoCG are responsible for altered resting-state FC patterns in PTs. Results showed decreased FC between the STG and the left cerebellar posterior lobe (poCb), the right dorsolateral prefrontal cortex (DLPFC), and the left precentral gyrus (PrCG). Results also showed decreased FC between the PoCG and the right precuneus and the right DLPFC. We also found greater FCs between the PoCG and the bilateral poCb, the left middle temporal gyrus (MTG), and the left angular gyrus. In addition, the FCs between the STG and poCb, and DLPFC in PTs were positively correlated with history and Cox menstrual symptom scale (CMSS) scores, respectively, while the FCs between STG and PrCG were negatively correlated with the onset age of PDM. Our research found structural abnormalities and related FC changes in several brain regions that were mainly involved in the emotional and sensory aspects of menstrual pain in PDM. These findings could help us understand the occurrence of PDM from a neuroimaging perspective.

Abstract WP101: Vessel Wall Enhancement Is Associated With Symptomatic Adult Moyamoya Disease And Syndrome In An American Population

Introduction: Moyamoya Disease (MMD) and Moyamoya Syndrome (MMS) are chronic progressive cerebrovascular disease characterized by bilateral or unilateral stenotic arteries around the circle of Willis with subsequent development of collateral blood vessels. MMS is associated with conditions such as Down Syndrome (DS) or sickle cell disease (SCD). The presence of vessel wall enhancement (VWE) on high resolution magnetic resonance vessel wall imaging (HR MR VWI) in MMD or MMS is controversial. Recent studies suggest VWE is associated with recent ischemic or hemorrhagic stroke. The significance of VWE in MMD or MMS in non-Asian population has not been well established. Our study aimed to investigate the prevalence of VWE in adult MMD/MMS in the United States and identify its predictive value for stenosis progression. Methods: We retrospectively reviewed patients with MMD or MMS admitted to Clements University Hospital and Parkland Memorial Hospital affiliated with University of Texas Southwestern Medical Center from January 2014 to March 2022. Patients were included if HR MR VWI was performed during workup. Patients were excluded if intracranial atherosclerosis was the suspected stroke etiology from cardiovascular risk factors. The presence of the VWE on HR MR VWI and stenosis grading were evaluated by blinded neuroradiologists and vascular neurologists. Symptomatic disease was defined as ischemic stroke, hemorrhagic stroke or transient ischemic attack within 24 months before HR MR VWI was obtained. Results: A total of 32 patients were included, of which 28 had MMD, 3 had MMS from SCD and 1 had MMS from DS. Mean age at diagnosis was 34 ± 10 years old, and 29 (90.6%) were female. VWE was seen in 22 (68.8%) patients. VWE is more common in symptomatic disease than asymptomatic disease (95% vs 20%). 24 patients had follow up MR angiogram with average time from HR MR VWI of 25.8 ± 16.7 months. Among 12 patients with 16 non-occlusive arteries, stenosis progression was seen in 67% of arteries with VWE compared to 25% of arteries without VWE. Conclusions: In a North American population with MMD or MMS, VWE on HR MR VWI was more common in symptomatic disease. The presence of VWE was associated with increased risk of stenosis progression. More studies are needed to confirm these findings.

Effect of Mid-Basilar Artery Angle and Plaque Characteristics on Pontine Infarction in Patients with Basilar Artery Plaque.

The basilar artery (BA) geometry and plaque characteristics may play an important role in the development of atherosclerosis. This study was performed to explore the relationship between the mid-BA angle and plaque characteristics and its effect on pontine infarction using high-resolution magnetic resonance imaging and three-dimensional time-of-flight magnetic resonance angiography. In total, 77 patients with BA plaques were included in this study. According to the presence of acute pontine infarction on diffusion-weighted imaging, the patients were divided into a pontine infarction group and pontine non-infarction group. The mid-BA angle, plaque burden, stenosis ratio, positive remodeling, and intraplaque hemorrhage were evaluated to investigate their effects on stroke. The pontine infarction group had a greater plaque burden, stenosis ratio, positive remodeling, and mid-BA angle than the pontine non-infarction group. The correlation between the plaque burden and mid-BA angle was the highest (r=0.441, P＜0.001). Multivariate logistic regression analysis showed that the plaque burden (odds ratio, 1.164; 95% confidence interval, 1.093-1.241; P＜0.001) was an independent risk factor for pontine infarction. The mid-BA angle may increase the incidence of pontine infarction by increasing the plaque burden.

Studying the imaging features and infarction mechanism of vertebrobasilar dolichoectasia with high-resolution magnetic resonance imaging.

The mechanisms underlying ischemic infarction in patients with vertebrobasilar dolichoectasia (VBD) remain unclear. In this study, we retrospectively analyzed the imaging characteristics of high-resolution magnetic resonance imaging (HR-MRI) in patients with VBD to explore the possible mechanisms of ischemic stroke (IS) in patients with VBD. Patients with VBD were recruited from the HR-MRI database between July 2017 and June 2021. HR-MRI was used to evaluate the diameter, bifurcation height, laterality, arterial dissection, and atherosclerotic plaques of the basilar artery (BA). Transcranial Doppler was used to measure the vertebrobasilar mean velocity (Vm), peak systolic velocity (Vs), end-diastolic velocity (Vd), and pulsatile index. Twenty-six patients with VBD were enrolled, of which 15 had IS and 11 did not. The incidence of classical vascular risk factors, including age, sex, hypertension, diabetes, and hypercholesterolemia, did not differ significantly between the two groups. The BA diameters of the stroke group were significantly higher than that of the nonstroke group (6.57 ± 1.00 mm vs. 5.06 ± 0.50 mm, p=0.000). The height of the BA bifurcation in the stroke and nonstroke groups was statistically significant (p=0.002). Compared with the nonstroke group, the Vm, Vs, and Vd of the BA in the stroke group were lower, but the difference was not significant. In the 16 patients with atherosclerotic stenosis, 30 atherosclerotic plaques were found in the BA, 18 (60%) in the greater curvature, and 12 (40%) in the lesser curvature. In addition, one artery dissection (on the lesser curvature) and two dissecting aneurysms (on the greater curvature) were found in the BA of three patients, respectively. The BA diameter and bifurcation height are factors related to IS in patients with VBD. The mechanism of stroke in patients with VBD may involve abnormal hemodynamics, artery dissection, and atherosclerosis. HR-MRI is a useful method for evaluating the risk and underlying mechanism of stroke in patients with VBD.

Intracranial plaque characteristics on high-resolution MRI and high-sensitivity C-reactive protein levels: association and clinical relevance in acute cerebral infarction

To investigate the association between intracranial plaque characteristics and high-sensitivity C-reactive protein (hs-CRP) levels, and their combined effects on the occurrence of acute cerebral infarction (ACI). One hundred and forty-three patients with recent ischaemic events in the territory of middle cerebral artery or basilar artery were enrolled and divided into the ACI group (n=93) and non-ACI group (n=50) according to clinical data and diffusion-weighting imaging (DWI) results. All recruited patients underwent high-resolution magnetic resonance imaging (MRI) to assess intracranial plaque characteristics, including plaque enhancement, standardised wall index, stenosis ratio, T1 hyperintense component, remodelling pattern, plaque area, plaque burden, and maximum wall thickness. hs-CRP levels were further grouped into the low group (<1 mg/l), the intermediate group (1-3 mg/l), and the high group (≥3 mg/l). Multivariate logistic regression and receiver operating characteristic curve were constructed to evaluate the association between intracranial plaque characteristics and hs-CRP levels, as well as their synergistic effects on determining the occurrence of ACI. High hs-CRP levels were associated with strong plaque enhancement (p<0.001, odds ratio [OR]=7.497). Strong plaque enhancement (p=0.002, OR=2.109) and high hs-CRP levels (p=0.009, OR=3.893) were independently associated with the occurrence of ACI after adjustments for sex, age, and other traditional atherosclerotic risk factors. The combination of hs-CRP levels and strong plaque enhancement provided incremental information to determine ACI with an AUC of 0.823, which was significantly higher than that of strong plaque enhancement (0.711) and hs-CRP levels (0.686), respectively. High hs-CRP levels were associated with strong plaque enhancement. The synergistic effects of hs-CRP levels and strong plaque enhancement provided incremental effects on the occurrence of ACI.

The interaction between first-episode drug-naïve schizophrenia and age based on gray matter volume and its molecular analysis: a multimodal magnetic resonance imaging study.

Schizophrenia is a neurodevelopmental disorder characterized by progressive and widespread gray matter (GM) atrophy. Studies have shown that normal brain development has an impact on schizophrenia-induced GM alterations. However, the neuropathology and underlying molecular mechanisms of interaction between age and schizophrenia are unclear. This study enrolled 66/84 first-episode drug-naïve patients with early-onset/adult-onset schizophrenia ((EOS)/(AOS)) and matched normal controls (NC) (46 adolescents/73 adults), undergoing T1-weighted high-resolution magnetic resonance imaging. Gray matter volume (GMV) in four groups was detected using 2-way analyses of variance with diagnosis and age as factors. Then, factors-related volume maps and neurotransmitter maps were spatially correlated using JuSpace to determine the relationship to molecular structure. Compared to AOS, EOS and adult NC had larger GMV in right middle frontal gyrus. Compared to adolescent NC, EOS and adult NC had smaller GMV in right lingual gyrus, right fusiform gyrus, and right cerebellum_6. Disease-induced GMV reductions were mainly distributed in frontal, parietal, thalamus, visual, motor cortex, and medial temporal lobe structures. Age-induced GMV alterations were mainly distributed in visual and motor cortex. The changed GMV induced by schizophrenia, age, and their interaction was related to dopaminergic and serotonergic receptors. Age is also related to glutamate receptors, and schizophrenia is also associated with GABAaergic and noradrenergic receptors. Our results revealed the multimodal neural mechanism of interaction between disease and age. We emphasized age-related GM abnormalities of ventral stream of visual perceptual pathways and high-level cognitive brain in EOS, which may be affected by imbalance of excitatory and inhibitory neurotransmitters.

Application of 1H HR-MAS NMR-Based Metabolite Fingerprinting of Marine Microalgae

Natural products from the marine environment as well as microalgae, have been known for the complexity of the metabolites they produce due to their adaptability to different environmental conditions, which has been an inexhaustible source of several bioactive properties, such as antioxidant, anti-tumor, and antimicrobial. This study aims to characterize the main metabolites of three species of microalgae (Nannochloropsis oceanica, Chaetoceros muelleri, and Conticribra weissflogii), which have important applications in the biofuel and nutrition industries, by 1H High-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR), a method which is non-destructive, is highly reproducible, and requires minimal sample preparation. Even though the three species were found in the same ecosystem and a superior production of lipid compounds was observed, important differences were identified in relation to the production of specialized metabolites. These distinct properties favor the use of these compounds as leaders in the development of new bioactive compounds, especially against environmental, human, and animal pathogens (One Health), and demonstrate their potential in the development of alternatives for aquaculture.

Systemic immune-inflammation index is associated with aneurysmal wall enhancement in unruptured intracranial fusiform aneurysms.

Inflammation plays a key role in the progression of intracranial aneurysms. Aneurysmal wall enhancement (AWE) correlates well with inflammatory processes in the aneurysmal wall. Understanding the potential associations between blood inflammatory indices and AWE may aid in the further understanding of intracranial aneurysm pathophysiology. We retrospectively reviewed 122 patients with intracranial fusiform aneurysms (IFAs) who underwent both high-resolution magnetic resonance imaging and blood laboratory tests. AWE was defined as a contrast ratio of the signal intensity of the aneurysmal wall to that of the pituitary stalk ≥ 0.90. The systemic immune-inflammation (SII) index (neutrophils × platelets/lymphocytes) was calculated from laboratory data and dichotomized based on whether or not the IFA had AWE. Aneurysmal symptoms were defined as sentinel headache or oculomotor nerve palsy. Multivariable logistic regression and receiver operating characteristic curve analyses were performed to determine how well the SII index was able to predict AWE and aneurysmal symptoms. Spearman's correlation coefficients were used to explore the potential associations between variables. This study included 95 patients, of whom 24 (25.3%) presented with AWE. After adjusting for baseline differences in neutrophil to lymphocyte ratios, leukocytes, and neutrophils in the multivariable logistic regression analysis, smoking history (P = 0.002), aneurysmal symptoms (P = 0.047), maximum diameter (P = 0.048), and SII index (P = 0.022) all predicted AWE. The SII index (P = 0.038) was the only independent predictor of aneurysmal symptoms. The receiver operating characteristic curve analysis revealed that the SII index was able to accurately distinguish IFAs with AWE (area under the curve = 0.746) and aneurysmal symptoms (area under the curve = 0.739). An early elevation in the SII index can independently predict AWE in IFAs and is a potential new biomarker for predicting IFA instability.

Identifying vulnerable plaques: A 3D carotid plaque radiomics model based on HRMRI.

Identification of vulnerable carotid plaque is important for the treatment and prevention of stroke. In previous studies, plaque vulnerability was assessed qualitatively. We aimed to develop a 3D carotid plaque radiomics model based on high-resolution magnetic resonance imaging (HRMRI) to quantitatively identify vulnerable plaques. Ninety patients with carotid atherosclerosis who underwent HRMRI were randomized into training and test cohorts. Using the radiological characteristics of carotid plaques, a traditional model was constructed. A 3D carotid plaque radiomics model was constructed using the radiomics features of 3D T1-SPACE and its contrast-enhanced sequences. A combined model was constructed using radiological and radiomics characteristics. Nomogram was generated based on the combined models, and ROC curves were utilized to assess the performance of each model. 48 patients (53.33%) were symptomatic and 42 (46.67%) were asymptomatic. The traditional model was constructed using intraplaque hemorrhage, plaque enhancement, wall remodeling pattern, and lumen stenosis, and it provided an area under the curve (AUC) of 0.816 vs. 0.778 in the training and testing sets. In the two cohorts, the 3D carotid plaque radiomics model and the combined model had an AUC of 0.915 vs. 0.835 and 0.957 vs. 0.864, respectively. In the training set, both the radiomics model and the combination model outperformed the traditional model, but there was no significant difference between the radiomics model and the combined model. HRMRI-based 3D carotid radiomics models can improve the precision of detecting vulnerable carotid plaques, consequently improving risk classification and clinical decision-making in patients with carotid stenosis.

Defining Occult High-Risk Cysts of the Pineal Region: A Case Series.

Absence of hydrocephalus on neuroimaging may impart a false sense of security for patients with pineal cysts. In this case series, we characterize a subset of patients with pineal cysts having an occult presentation. Unifying features of worsening paroxysmal headaches suggesting intermittent obstructive hydrocephalus and radiographic evidence of third ventricular invagination characterize these patients as high risk. To define features of occult, high-risk pineal cysts and outcomes of endoscopic cyst fenestration. Charts were retrospectively reviewed for patients with pineal cysts evaluated at our institution between 2018 and 2021 who underwent endoscopic cyst fenestration. To capture cysts presenting as occult, patients were excluded if hydrocephalus was noted at presentation. Relevant clinical history, imaging, operative data, and clinical outcomes were reviewed. Of 50 pineal cyst patients, 4 satisfied inclusion criteria. All patients presented with worsening paroxysmal headaches. In addition, 75% (3/4) also experienced intermittent syncope. Patients exhibited no hydrocephalus (n = 3) or fluctuating ventricular size on longitudinal imaging (n = 1). In all cases, high-resolution sagittal 3-dimensional T2 magnetic resonance imaging demonstrated invagination of the cyst anteriorly into the posterior third ventricle. All patients underwent endoscopic cyst fenestration with complete symptom resolution (mean follow-up of 20.6 months; range 3.5-37.4 months). The clinical history for occult, high-risk pineal cysts is notable for worsening paroxysmal headaches and episodic alterations of consciousness suggesting intermittent obstructive hydrocephalus. Because ventricular size can appear normal on standard imaging protocols, clinical suspicion should trigger workup with high-resolution magnetic resonance imaging designed to detect these cysts. Endoscopic cyst fenestration is a safe and efficacious management strategy.

The Rostral Zona Incerta: A Subcortical Integrative Hub and Potential Deep Brain Stimulation Target for Obsessive-Compulsive Disorder

BackgroundThe zona incerta (ZI) is involved in mediating survival behaviors and is connected to a wide range of cortical and subcortical structures, including key basal ganglia nuclei. Based on these connections and their links to behavioral modulation, we propose that the ZI is a connectional hub for mediating between top-down and bottom-up control and a possible target for deep brain stimulation for obsessive-compulsive disorder. MethodsWe analyzed the trajectory of cortical fibers to the ZI in nonhuman and human primates based on tracer injections in monkeys and high-resolution diffusion magnetic resonance imaging in humans. The organization of cortical and subcortical connections within the ZI were identified in the nonhuman primate studies. ResultsMonkey anatomical data and human diffusion magnetic resonance imaging data showed a similar trajectory of fibers/streamlines to the ZI. Prefrontal cortex/anterior cingulate cortex terminals all converged within the rostral ZI, with dorsal and lateral areas being most prominent. Motor areas terminated caudally. Dense subcortical reciprocal connections included the thalamus, medial hypothalamus, substantia nigra/ventral tegmental area, reticular formation, and pedunculopontine nucleus and a dense nonreciprocal projection to the lateral habenula. Additional connections included the amygdala, dorsal raphe nucleus, and periaqueductal gray. ConclusionsDense connections with dorsal and lateral prefrontal cortex/anterior cingulate cortex cognitive control areas and the lateral habenula and the substantia nigra/ventral tegmental area, coupled with inputs from the amygdala, hypothalamus, and brainstem, suggest that the rostral ZI is a subcortical hub positioned to modulate between top-down and bottom-up control. A deep brain stimulation electrode placed in the rostral ZI would not only involve connections common to other deep brain stimulation sites but also capture several critically distinctive connections.

High-resolution, respiratory-resolved coronary MRA using a Phyllotaxis-reordered variable-density 3D cones trajectory

PurposeTo develop a respiratory-resolved motion-compensation method for free-breathing, high-resolution coronary magnetic resonance angiography (CMRA) using a 3D cones trajectory. MethodsTo achieve respiratory-resolved 0.98 mm resolution images in a clinically relevant scan time, we undersample the imaging data with a variable-density 3D cones trajectory. For retrospective motion compensation, translational estimates from 3D image-based navigators (3D iNAVs) are used to bin the imaging data into four phases from end-expiration to end-inspiration. To ensure pseudo-random undersampling within each respiratory phase, we devise a phyllotaxis readout ordering scheme mindful of eddy current artifacts in steady state free precession imaging. Following binning, residual 3D translational motion within each phase is computed using the 3D iNAVs and corrected for in the imaging data. The noise-like aliasing characteristic of the combined phyllotaxis and cones sampling pattern is leveraged in a compressed sensing reconstruction with spatial and temporal regularization to reduce aliasing in each of the respiratory phases. ResultsIn initial studies of six subjects, respiratory motion compensation using the proposed method yields improved image quality compared to non-respiratory-resolved approaches with no motion correction and with 3D translational correction. Qualitative assessment by two cardiologists and quantitative evaluation with the image edge profile acutance metric indicate the superior sharpness of coronary segments reconstructed with the proposed method (P < 0.01). ConclusionWe have demonstrated a new method for free-breathing, high-resolution CMRA based on a variable-density 3D cones trajectory with modified phyllotaxis ordering and respiratory-resolved motion compensation with 3D iNAVs.

Imaging and Hemodynamic Characteristics of Vulnerable Carotid Plaques and Artificial Intelligence Applications in Plaque Classification and Segmentation.

Stroke is a massive public health problem. The rupture of vulnerable carotid atherosclerotic plaques is the most common cause of acute ischemic stroke (AIS) across the world. Currently, vessel wall high-resolution magnetic resonance imaging (VW-HRMRI) is the most appropriate and cost-effective imaging technique to characterize carotid plaque vulnerability and plays an important role in promoting early diagnosis and guiding aggressive clinical therapy to reduce the risk of plaque rupture and AIS. In recent years, great progress has been made in imaging research on vulnerable carotid plaques. This review summarizes developments in the imaging and hemodynamic characteristics of vulnerable carotid plaques on the basis of VW-HRMRI and four-dimensional (4D) flow MRI, and it discusses the relationship between these characteristics and ischemic stroke. In addition, the applications of artificial intelligence in plaque classification and segmentation are reviewed.

New Anti-Inflammatory β-Resorcylic Acid Lactones Derived from an Endophytic Fungus, Colletotrichum sp.

The endophytic fungus Colletotrichum gloeosprioides JS0419, isolated from the leaves of the halophyte Suaeda japonica, produced four new β-resorcylic acid derivatives, colletogloeopyrones A and B (1 and 2) and colletogloeolactones A and B (3 and 4), and seven known β-resorcylic acid lactones (RALs). The structures of these compounds were elucidated via analysis of the high-resolution mass spectrometry and nuclear magnetic resonance data. Compounds 1 and 2 showed a dihydrobenzopyranone ring with a linear C9 side chain, which is rarely observed in RALs. All isolated compounds were evaluated for their anti-inflammatory activities. Colletogloeopyrone A (1), monocillin II (5), and monocillin II glycoside (6) were effective in reducing nitric oxide production without cytotoxicity. They also inhibited the secretion of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), as demonstrated by the expression of mRNA corresponding to IL-6 and TNF-α. Mechanistically, compounds 5 and 6 significantly inhibited the protein expression of nuclear factor-κB, IκBα, IKKα/β, inducible nitric oxide synthase, and cyclooxygenase (COX)-2, whereas compound 1 only inhibited COX-2 expression. This study indicated that RAL-type compounds 1, 5, and 6 demonstrated potential anti-inflammatory activity by inhibiting the synthesis of pro-inflammatory cytokines.

Probing microstructure of solid-state synthesized LiCoO2 with MAS NMR spectroscopy

LiCoO2 is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density, good thermal stability, and stable voltage platform. Recent works on LiCoO2 have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity. However, an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation. Here we employ high-resolution solid-state nuclear magnetic resonance (NMR) spectroscopy to study the local atomic environments in LiCoO2 synthesized with three common sintering methods. While one-dimensional 7Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry, both 7Li and 59Co relaxation times are highly dependent on the sintering method. We prove that the two-step sintering method favors the elimination of unreacted Co3O4, thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO2/LGPS/LiIn, which is in accordance with its narrowest 7Li linewidth and the longest 7Li/59Co T1.

Atrophy in subcortical gray matter in adult patients with moyamoya disease

BackgroundAcute cerebrovascular accidents, long-term hypoperfusion, and/or remote neuronal degeneration may lead to structural alterations in patients with moyamoya disease (MMD). This study sought to comprehensively investigate the distribution characteristics of subcortical gray matter volume and their correlations with angiographic changes in the intracranial artery in patients with MMD. MethodOne hundred forty-two patients with MMD and 142 age- and sex-matched healthy controls underwent 3-dimensional high-resolution structural magnetic resonance imaging. Volumes of subcortical gray matter and subregions of the hippocampus and amygdala were calculated, and the degree of stenosis/occlusion of intracranial arteries in patients with MMD was evaluated on MR angiography.ResultsVolume reductions in the thalamus, caudate, putamen, hippocampus, amygdala, pallidum, and nucleus accumbens were found in patients with MMD. Hippocampal subfields and amygdala subnuclei in patients with MMD showed distinct vulnerability, and morphological alterations in specific subregions were more obvious than in the whole hippocampus/amygdala. Volume loss in several subcortical areas was related to disease duration and intracranial arterial changes.ConclusionsOur findings revealed structural alteration patterns of subcortical gray matter in MMD. The specific atrophy in subregions of the hippocampus and the amygdala suggested potential cognitive and affective impairments in MMD, which warrants further investigation. Chronic cerebral hemodynamic alterations in MMD may play a pivotal role in morphological changes in subcortical areas.

Genomic and Metabolite Profiling Reveal a Novel Streptomyces Strain, QHH-9511, from the Qinghai-Tibet Plateau.

The prevalence of superbugs, represented by methicillin-resistant Staphylococcus aureus (MRSA), has become a serious clinical and public safety concern with rising incidence in hospitals. Polyketides with diverse chemical structures harbor many antimicrobial activities, including those of rifampin and rapamycin against MRSA. Streptomyces sp. QHH-9511 was isolated from a niche habitat in the Qinghai-Tibet Plateau and used to produce antibacterial metabolites. Herein, an integrated approach combining genome mining and metabolic analysis were employed to decipher the chemical origin of the antibacterial components with pigmented properties in strain QHH-9511, a novel Streptomyces species from a lichen symbiont on the Qinghai-Tibet Plateau. Genomic phylogeny assembled at the chromosome level revealed its unique evolutionary state. Further genome mining uncovered 36 candidate gene clusters, most of which were uncharacterized. Meanwhile, based on liquid chromatography coupled to diode array detection mass spectrometry, a series of granaticins, BSMs, chromones, phaeochromycins, and related molecules were discovered by using the Global Natural Product Social molecular networking platform. Subsequently, several pigment compounds were isolated and identified by high-resolution mass spectrometry and/or nuclear magnetic resonance, among which the structure-activity relationships of seven aromatic polyketides showed that the fused lactone ring of the C-2 carboxyl group could increase antibacterial activity. Genetic experiments indicated that all seven aromatic polyketides are a series of metabolic shunts produced by a single type II polyketide synthase (PKS) cluster. Comparative genomic analysis of granaticin producers showed that the granaticin gene cluster is widely distributed. This study provides an efficient method to combine genome mining and metabolic profiling techniques to uncover bioactive metabolites derived from specific habitats, while deepening our understanding of aromatic polyketide biosynthesis. IMPORTANCE Undescribed microorganisms from special habitats are being screened for anti-superbug drug molecules. In a project to screen actinomycetes for anti-MRSA activity, we isolated a Streptomyces strain from Qinghai Lake lichens. The phylogeny based on the genome assembled at the chromosome level revealed this strain's unique evolutionary state. The chemical origins of the antibacterial components with pigment properties in strain QHH-9511 were determined using an integrated approach combining genome mining and metabolic analysis. Further genome mining uncovered 36 secondary metabolite gene clusters, the majority of which were previously unknown. A series of aromatic compounds were discovered using molecular network analysis, separation, and extraction. Genetic experiments revealed that all seven aromatic polyketides are a series of metabolic shunts produced by a single cluster of type II PKSs. This study describes a method for identifying novel Streptomyces from specific habitats by combining genome mining with metabolic profiling techniques.

MR microneurography of human peripheral fascicles using a clinical 3T MR scanner

Background and purposeKnowledge of nerve fascicular structures is essential for managing peripheral nerve disorders. This study aimed to investigate the feasibility of z-axis high-resolution magnetic resonance (MR) microneurography (zH-MRMN) in displaying the three-dimensional structures of tibial nerve fascicles in vivo using a 3T MR scanner. Materials and methodsTwelve volunteers underwent z-axis conventional-resolution MR microneurography (zC-MRMN) and zH-MRMN of tibial nerves. The visibility scores of the nerve fascicles (VSNFs) on axial zC-MRMN images and axial zH-MRMN multiplanar reformation (MPR) images were compared. The nerve fascicle appearances on the longitudinal zH-MRMN MPR images were described. ResultsIn the nerve segments whose long axes were perpendicular to the imaging planes of both zC-MRMN and zH-MRMN, the VSNFs were not significantly different between the axial images of the two modalities (P = 0.083). In the nerve segments whose long axes were not perpendicular to the imaging planes of zC-MRMN, the VSNFs on the axial zC-MRMN images were significantly lower than those on the axial zH-MRMN MPR images that were angled perpendicular to the long axis of the tibial nerve (P < 0.001). ConclusionsThe longitudinal zH-MRMN MPR images clearly displayed the changing features of the intraneural fascicles as well as the gross morphology of the tibial nerves. zH-MRMN can clearly delineate the topography of the tibial nerve fascicles in vivo through use of a 3T MR scanner.

Intracranial plaque with large lipid core is associated with embolic stroke of undetermined source.

To investigate an association between percentage lipid-rich necrotic core (LRNC) and an index ischemic stroke in an embolic stroke of undetermined source (ESUS) cohort. A total of 167 ESUS patients with 259 non-stenotic intracranial plaques including 155 ipsilateral and 104 contralateral to stroke were finally enrolled in the current analysis. The multi-dimensional parameters involving remodeling index (RI), plaque burden (PB), LRNC, discontinuity of plaque surface (DPS), intraplaque hemorrhage (IPH), and vulnerable plaque defined as presence of complicated plaque were evaluated by high-resolution magnetic resonance imaging. We found that %LRNC was an independent predictor for ESUS in model 1 (OR: 2.574, 95% CI: 1.854-3.573, P < 0.001), and model 2 (OR: 2.550, 95% CI: 1.835-3.545, P < 0.001), but the association was not seen in PB. In receiver operating characteristic curve analysis, the discrimination of LRNC for ESUS was significantly superior to that of PB (absolute difference: 0.121, 95% CI: 0.056-0.205, P < 0.001). Importantly, a significantly positive synergy between the remodeling pattern and LRNC in response to plaque vulnerability was found by Sankey diagram (P for interaction=0.001). This is the first report that LRNC, beyond PB, may be correlated with an index ESUS, and a synergistic effect between positive remodeling and larger LRNC could promote plaque vulnerability. The findings suggest that a potential target subgroup may benefit from stroke prevention with intensive statin, although this must be confirmed in future.

HRMAS-NMR and simulation study of the self-assembly of surfactants on carbon nanotubes.

Polyethoxylated surfactants, such as those of the Tween and Pluronic series, are commonly used to disperse carbon nanotubes (CNTs) and other nanoparticles. However, the current understanding of the nature of interactions between these surfactants and CNTs is limited. The nature of the interactions between surfactants (Tween-80 [T80] and Pluronic F68 [PF68]) and CNTs was investigated using high-resolution magic angle spinning nuclear magnetic resonance (HRMAS-NMR) and coarse-grained molecular dynamics (MD) simulations. HRMAS-NMR revealed that T80 molecules interact with single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs) via the oleyl chain, whereas PF68 molecules interact with the surface of SWCNTs and MWCNTs via the polypropylene oxide residues. The polyethylene oxide chains were oriented towards the external aqueous environment. The HRMAS-NMR results were supported by MD simulations, and the latter provided further insights into the nature of the interactions.