Quantitative analysis of fiber tractography in cervical spondylotic myelopathy

Background context: Diffusion tensor fiber tractography is an emerging tool for the visualization of spinal cord microstructure. However, there are few quantitative analyses of the damage in the nerve fiber tracts of the myelopathic spinal cord. Purpose: The aim of this study was to develop a quantitative approach for fiber tractography analysis in cervical spondylotic myelopathy (CSM). Study design/setting: Prospective study on a series of patients. Materials and methods: A total of 22 volunteers were recruited with informed consent, including 15 healthy subjects and 7 CSM patients. The clinical severity of CSM was evaluated using modified Japanese Orthopedic Association (JOA) score. The microstructure of myelopathic cervical cord was analyzed using diffusion tensor imaging. Diffusion tensor imaging was performed with a 3.0-T magnetic resonance imaging scanner using pulsed gradient, spin-echo, echo-planar imaging sequence. Fiber tractography was generated via TrackVis with fractional anisotropy threshold set at 0.2 and angle threshold at 40. Region of interest (ROI) was defined to cover C4 level only or the whole-length cervical spinal cord from C1 to C7 for analysis. The length and density of tracked nerve bundles were measured for comparison between healthy subjects and CSM patients. Results: The length of tracked nerve bundles significantly shortened in CSM patients compared with healthy subjects (healthy: 6.85-77.90 mm, CSM: 0.68-62.53 mm). The density of the tracked nerve bundles was also lower in CSM patients (healthy: 086±0.03, CSM: 0.80±0.06, p<.05). Although the definition of ROI covering C4 only or whole cervical cord appeared not to affect the trend of the disparity between healthy and myelopathic cervical cords, the density of the tracked nerve bundle through whole myelopathic cords was in an association with the modified JOA score in CSM cases (r=0.949, p=.015), yet not found with ROI at C4 only (r=0.316, p=.684). Conclusions: The quantitative analysis of fiber tractography is a reliable approach to detect cervical spondylotic myelopathic lesions compared with healthy spinal cords. It could be employed to delineate the severity of CSM. © 2013 Published by Elsevier Inc. All rights reserved.postprin

Diffusion tensor imaging of somatosensory tract in cervical spondylotic myelopathy and its link with electrophysiological evaluation

Background and context Abnormal somatosensory evoked potential (SEP) (ie, prolonged latency) has been associated with poor surgical prognosis of cervical spondylotic myelopathy (CSM). Purpose To further characterize the extent of microstructural damage to the somatosensory tract in CSM patients using diffusion tensor imaging (DTI). Study design/setting Retrospective study. Patient sample A total of 40 volunteers (25 healthy subjects and 15 CSM patients). Outcome measures Clinical, electrophysiological, and radiological evaluations were performed using the modified Japanese Orthopedic Association (mJOA) scoring system, SEP, and cord compression ratio in anatomic magnetic resonance (MR) images, respectively. Axial diffusion MR images were taken using a pulsed gradient, spin-echo-echo-planar imaging sequence with a 3-T MR system. The diffusion indices in different regions of the spinal cord were measured. Methods Comparison of diffusion indices among healthy and myelopathic spinal cord with intact and impaired SEP responses were performed using one-way analysis of variance. Results In healthy subjects, fractional anisotropy (FA) values were higher in the dorsal (0.73±0.11) and lateral columns (0.72±0.13) than in the ventral column of white matter (0.58±0.10) (eg, at C4/5) (p<.05). FA was dramatically dropped in the dorsal (0.54±0.16) and lateral columns (0.51±0.13) with little change in the ventral column (0.48±0.15) at the compressive lesions in CSM patients. There were no significant differences in the mJOA scores or cord compression ratios between CSM patients with or without abnormal SEP. However, patients with abnormal SEP showed an FA decrease in the dorsal column cephalic to the lesion (0.56±0.06) (ie, at C1/2, compared with healthy subjects [0.66±0.02]), but the same decrease was not observed for those without a SEP abnormality (0.67±0.02). Conclusion Spinal tracts were not uniformly affected in the myelopathic cervical cord. Changes in diffusion indices could delineate focal or extensive myelopathic lesions in CSM, which could account for abnormal SEP. DTI analysis of spinal tracts might provide additional information not available from conventional diagnostic tools for prognosis of CSM. © 2014 Elsevier Inc. All rights reserved.postprin

Valid olfactory impairment tests can help identify mild cognitive impairment: an updated meta-analysis

BackgroundOlfactory testing is emerging as a potentially effective screening method for identifying mild cognitive impairment in the elderly population.ObjectiveOlfactory impairment is comorbid with mild cognitive impairment (MCI) in older adults but is not well-documented in subdomains of either olfactory or subtypes of cognitive impairments in older adults. This meta-analysis was aimed at synthesizing the differentiated relationships with updated studies.MethodsA systematic search was conducted in seven databases from their availability to April 2023. A total of 38 publications were included, including 3,828 MCI patients and 8,160 healthy older adults. Two investigators independently performed the literature review, quality assessment, and data extraction. The meta-analyses were conducted with Stata to estimate the average effects and causes of the heterogeneity.ResultsCompared to normal adults, MCI patients had severe impairments in olfactory function and severe deficits in specific domains of odor identification and discrimination. Olfactory impairment was more severe in patients with amnestic mild cognitive impairment than in patients with non-amnestic MCI. Diverse test instruments of olfactory function caused large heterogeneity in effect sizes.ConclusionValid olfactory tests can be complementary tools for accurate screening of MCI in older adults

CagA-positive Helicobacter pylori may promote and aggravate scrub typhus

Helicobacter pylori (H. pylori) infection may alter the host’s resistance to tsutsugamushi disease pathogens through the Th1 immune response, leading to potential synergistic pathogenic effects. A total of 117 scrub typhus cases at Beihai People’s Hospital and affiliated hospitals of Youjiang University for Nationalities and Medical Sciences were studied from January to December 2022, alongside 130 healthy individuals forming the control group. All participants underwent serum H. pylori antibody testing. The prevalence of H. pylori infection was significantly higher among scrub typhus patients (89.7%) compared to healthy individuals (54.6%) (p &lt; 0.05). Moreover, type I H. pylori infection was notably more prevalent in scrub typhus cases (67.5%) compared to healthy individuals (30%) (p &lt; 0.05). Multifactorial analysis demonstrated type I H. pylori infection as an independent risk factor for scrub typhus (adjusted odds ratio: 2.407, 95% confidence interval: 1.249–4.64, p = 0.009). Among scrub typhus patients with multiple organ damage, the prevalence of type I H. pylori infection was significantly higher (50.6%) than type II H. pylori infection (15.4%) (χ2 = 4.735, p = 0.030). These results highlight a higher incidence of H. pylori infection in scrub typhus patients compared to the healthy population. Additionally, type I H. pylori strain emerged as an independent risk factor for scrub typhus development. Moreover, individuals infected with type I H. pylori are more susceptible to multiple organ damage. These findings suggest a potential role of H. pylori carrying the CagA gene in promoting and exacerbating scrub typhus

A Method to Boost Naïve Bayesian Classifiers

In this paper, we introduce a new method to improve the perform- ance of combining boosting and nave Bayesian. Instead of combining boosting and Nave Bayesian learning directly, which was proved to be unsatisfactory to improve performance, we select the training samples dynamically by bootstrap method for the construction of nave Bayesian classifiers, and hence generate very different or unstable base classifiers for boosting. Besides, we devise a modification for the weight adjusting of boosting algorithm in order to achieve this goal: minimizing the overlapping errors of its constituent classifiers. We conducted series of experiments, which show that the new method not only has performance much better than nave Bayesian classifiers or directly boosted nave Bayesian ones, but also much quicker to obtain optimal performance than boosting stumps and boosting decision trees incorporated with nave Bayesian learning

Introducing Large Genomic Deletions in Human Pluripotent Stem Cells Using CRISPR‐Cas3

CRISPR‐Cas systems provide researchers with eukaryotic genome editing tools and therapeutic platforms that make it possible to target disease mutations in somatic organs. Most of these tools employ Type II (e.g., Cas9) or Type V (e.g., Cas12a) CRISPR enzymes to create RNA‐guided precise double‐strand breaks in the genome. However, such technologies are limited in their capacity to make targeted large deletions. Recently, the Type I CRISPR system, which is prevalent in microbes and displays unique enzymatic features, has been harnessed to effectively create large chromosomal deletions in human cells. Type I CRISPR first uses a multisubunit ribonucleoprotein (RNP) complex called Cascade to find its guide‐complementary target site, and then recruits a helicase‐nuclease enzyme, Cas3, to travel along and shred the target DNA over a long distance with high processivity. When introduced into human cells as purified RNPs, the CRISPR‐Cas3 complex can efficiently induce large genomic deletions of varying lengths (1‐100 kb) from the CRISPR‐targeted site. Because of this unique editing outcome, CRISPR‐Cas3 holds great promise for tasks such as the removal of integrated viral genomes and the interrogation of structural variants affecting gene function and human disease. Here, we provide detailed protocols for introducing large deletions using CRISPR‐Cas3. We describe step‐by‐step procedures for purifying the Type I‐E CRISPR proteins Cascade and Cas3 from Thermobifida fusca, electroporating RNPs into human cells, and characterizing DNA deletions using PCR and sequencing. We focus here on human pluripotent stem cells due to their clinical potential, but these protocols will be broadly useful for other cell lines and model organisms for applications including large genomic deletion, full‐gene or ‐chromosome removal, and CRISPR screening for noncoding elements, among others. © 2022 Wiley Periodicals LLC.Basic Protocol 1: Expression and purification of Tfu Cascade RNPSupport Protocol 1: Expression and purification of TfuCas3 proteinSupport Protocol 2: Culture of human pluripotent stem cellsBasic Protocol 2: Introduction of Tfu Cascade RNP and Cas3 protein into hPSCs via electroporationBasic Protocol 3: Characterization of genomic DNA lesions using long‐range PCR, TOPO cloning, and Sanger sequencingAlternate Protocol: Comprehensive analysis of genomic lesions by Tn5‐based next‐generation sequencingSupport Protocol 3: Single‐cell clonal isolationPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/171838/1/cpz1361.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/171838/2/cpz1361_am.pd

Carbon nanotubes as nanoreactors for fabrication of single-crystalline Mg3N2 nanowires

Due to fast decomposition of Mg3N2 in the presence of water in the atmosphere (Mg3N2 + 6H2O → 3Mg(OH)2 + 2NH3), the synthesis of single-crystalline Mg3N2 nanowires has been a challenge. Here, we demonstrate that carbon nanotubes may serve as nanoreactors for a simple thermal reaction process resulting in the first fabrication of high-quality, large-yield, single-crystalline Mg3N2 nanowires. The Mg 3N2 nanowires are homogeneously sheathed over their entire lengths with very thin graphitic carbon tubular layers, which effectively prevent their decomposition (even when the samples are put into water or exposed to atmosphere for several months). We have systematically analyzed for the first time the Mg3N2 nanomaterlal by means of transmission electron microscopy (TEM), high-resolution TEM, and electron diffraction. Successful fabrication of carbon sheath protected Mg3N2 nanowires may promote further experimental studies on their crystal structures and properties.</p