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Nature Reviews. Neurology Jun 2016Over the past few decades, MRI-based visualization of demyelinated CNS lesions has become pivotal to the diagnosis and monitoring of multiple sclerosis (MS). In this... (Review)
Review
Over the past few decades, MRI-based visualization of demyelinated CNS lesions has become pivotal to the diagnosis and monitoring of multiple sclerosis (MS). In this Review, we outline current efforts to correlate imaging findings with the pathology of lesion development in MS, and the pitfalls that are being encountered in this research. Multimodal imaging at high and ultra-high magnetic field strengths is yielding biologically relevant insights into the pathophysiology of blood-brain barrier dynamics and both active and chronic inflammation, as well as mechanisms of lesion healing and remyelination. Here, we parallel the results in humans with advances in imaging of a primate model of MS - experimental autoimmune encephalomyelitis (EAE) in the common marmoset - in which demyelinated lesions resemble their human counterparts far more closely than do EAE lesions in the rodent. This approach holds promise for the identification of innovative biological markers, and for next-generation clinical trials that will focus more on tissue protection and repair.
Topics: Animals; Callithrix; Disease Models, Animal; Disease Progression; Encephalomyelitis, Autoimmune, Experimental; Humans; Magnetic Resonance Imaging; Multiple Sclerosis
PubMed: 27125632
DOI: 10.1038/nrneurol.2016.59 -
Frontiers in Cell and Developmental... 2021DNA interstrand crosslinks (ICLs) are covalently bound DNA lesions, which are commonly induced by chemotherapeutic drugs, such as cisplatin and mitomycin C or endogenous... (Review)
Review
DNA interstrand crosslinks (ICLs) are covalently bound DNA lesions, which are commonly induced by chemotherapeutic drugs, such as cisplatin and mitomycin C or endogenous byproducts of metabolic processes. This type of DNA lesion can block ongoing RNA transcription and DNA replication and thus cause genome instability and cancer. Several cellular defense mechanism, such as the Fanconi anemia pathway have developed to ensure accurate repair and DNA replication when ICLs are present. Various structure-specific nucleases and translesion synthesis (TLS) polymerases have come into focus in relation to ICL bypass. Current models propose that a structure-specific nuclease incision is needed to unhook the ICL from the replication fork, followed by the activity of a low-fidelity TLS polymerase enabling replication through the unhooked ICL adduct. This review focuses on how, in parallel with the Fanconi anemia pathway, PCNA interactions and ICL-induced PCNA ubiquitylation regulate the recruitment, substrate specificity, activity, and coordinated action of certain nucleases and TLS polymerases in the execution of stalled replication fork rescue via ICL bypass.
PubMed: 34262911
DOI: 10.3389/fcell.2021.699966 -
Frontiers in Psychology 2017Traditionally, philosophers have appealed to the phenomenological similarity between visual experience and visual imagery to support the hypothesis that there is... (Review)
Review
Traditionally, philosophers have appealed to the phenomenological similarity between visual experience and visual imagery to support the hypothesis that there is significant overlap between the perceptual and imaginative domains. The current evidence, however, is inconclusive: while evidence from transcranial brain stimulation seems to support this conclusion, neurophysiological evidence from brain lesion studies (e.g., from patients with brain lesions resulting in a loss of mental imagery but not a corresponding loss of perception and vice versa) indicates that there are functional and anatomical dissociations between mental imagery and perception. Assuming that the mental imagery and perception do not overlap, at least, to the extent traditionally assumed, then the question arises as to what exactly mental imagery is and whether it parallels perception by proceeding via several functionally distinct mechanisms. In this review, we argue that even though there may not be a shared mechanism underlying vision for perception and conscious imagery, there is an overlap between the mechanisms underlying vision for action and unconscious visual imagery. On the basis of these findings, we propose a modification of Kosslyn's model of imagery that accommodates unconscious imagination and explore possible explanations of the quasi-pictorial phenomenology of conscious visual imagery in light of the fact that its underlying neural substrates and mechanisms typically are distinct from those of visual experience.
PubMed: 28588527
DOI: 10.3389/fpsyg.2017.00799 -
Biochimica Et Biophysica Acta Jan 2005New methods for analyzing tau fibrillization have yielded insights into the biochemical transitions involved in the process. Here we review the parallels between the... (Review)
Review
New methods for analyzing tau fibrillization have yielded insights into the biochemical transitions involved in the process. Here we review the parallels between the sequential progression of tau fibrillization observed macroscopically in Alzheimer's disease (AD) lesions and the pathway of tau aggregation observed in vitro with purified tau preparations. In addition, pharmacological agents for further dissection of fibrillization mechanism and lesion formation are discussed.
Topics: Alzheimer Disease; Amyloid beta-Peptides; Brain Chemistry; In Vitro Techniques; Microtubule-Associated Proteins; Models, Biological; Mutation; Neurofibrillary Tangles; Phosphorylation; Protein Isoforms; Recombinant Proteins; tau Proteins
PubMed: 15615636
DOI: 10.1016/j.bbadis.2004.06.016 -
Heliyon Jul 2020to compare arrest rates and colour change in carious lesions in primary teeth using two different silver fluoride solutions with and without potassium iodide (KI).
OBJECTIVES
to compare arrest rates and colour change in carious lesions in primary teeth using two different silver fluoride solutions with and without potassium iodide (KI).
METHODS
The study was a four-armed, parallel-design randomised controlled trial and investigated four protocols for caries arrest at 6m. Children in Group 1 and Group 2 received Rivastar Silver Diammine Fluoride (SDF), and Children in Group 3 and Group 4 received an aqueous silver fluoride solution (AgF). Children in Group 2 and Group 4 received a two-step procedure where application of the AgF or SDF solution was followed by KI.
RESULTS
At the six-month follow-up 446 (82.2%) children were re-examined. The arrest rate across the full sample was 51.4% and there were no significant differences in arrest rate by type of silver fluoride therapy. The lesion size, tooth type, surface type, presence of plaque on the carious lesion and caries increment all had an influence on caries arrest. Once clustering effects were accounted for, the use of KI was associated with a higher chance of arrest (OR 1.23; P-value 0.008) and a lower chance of the lesion darkening (OR 0.73; P-value <0.001).
CONCLUSIONS
The combination of AgF & KI was associated with the most favourable clinical outcomes in terms of caries arrest and lesion colour.
CLINICAL SIGNIFICANCE
The major draw-back of arrest of caries treatment with silver fluoride solutions is that it can create an appearance which may be aesthetically unacceptable. This study explores ways in which the base colour of lesions could be improved and as such provide the opportunity for better aesthetic outcomes for children afflicted with a severe burden of dental caries in their primary dentition, and in whom conventional treatment is not being provided.
PubMed: 32715116
DOI: 10.1016/j.heliyon.2020.e04287 -
European Radiology Nov 2023To compare examination time and image quality between artificial intelligence (AI)-assisted compressed sensing (ACS) technique and parallel imaging (PI) technique in MRI...
AI-assisted compressed sensing and parallel imaging sequences for MRI of patients with nasopharyngeal carcinoma: comparison of their capabilities in terms of examination time and image quality.
OBJECTIVE
To compare examination time and image quality between artificial intelligence (AI)-assisted compressed sensing (ACS) technique and parallel imaging (PI) technique in MRI of patients with nasopharyngeal carcinoma (NPC).
METHODS
Sixty-six patients with pathologically confirmed NPC underwent nasopharynx and neck examination using a 3.0-T MRI system. Transverse T2-weighted fast spin-echo (FSE) sequence, transverse T1-weighted FSE sequence, post-contrast transverse T1-weighted FSE sequence, and post-contrast coronal T1-weighted FSE were obtained by both ACS and PI techniques, respectively. The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and duration of scanning of both sets of images analyzed by ACS and PI techniques were compared. The images from the ACS and PI techniques were scored for lesion detection, margin sharpness of lesions, artifacts, and overall image quality using the 5-point Likert scale.
RESULTS
The examination time with ACS technique was significantly shorter than that with PI technique (p < 0.0001). The comparison of SNR and CNR showed that ACS technique was significantly superior with PI technique (p < 0.005). Qualitative image analysis showed that the scores of lesion detection, margin sharpness of lesions, artifacts, and overall image quality were higher in the ACS sequences than those in the PI sequences (p < 0.0001). Inter-observer agreement was evaluated for all qualitative indicators for each method, in which the results showed satisfactory-to-excellent agreement (p < 0.0001).
CONCLUSION
Compared with the PI technique, the ACS technique for MR examination of NPC can not only shorten scanning time but also improve image quality.
CLINICAL RELEVANCE STATEMENT
The artificial intelligence (AI)-assisted compressed sensing (ACS) technique shortens examination time for patients with nasopharyngeal carcinoma, while improving the image quality and examination success rate, which will benefit more patients.
KEY POINTS
• Compared with the parallel imaging (PI) technique, the artificial intelligence (AI)-assisted compressed sensing (ACS) technique not only reduced examination time, but also improved image quality. • Artificial intelligence (AI)-assisted compressed sensing (ACS) pulls the state-of-the-art deep learning technique into the reconstruction procedure and helps find an optimal balance of imaging speed and image quality.
Topics: Humans; Artificial Intelligence; Nasopharyngeal Carcinoma; Magnetic Resonance Imaging; Signal-To-Noise Ratio; Nasopharyngeal Neoplasms; Artifacts
PubMed: 37219618
DOI: 10.1007/s00330-023-09742-6 -
BMC Cardiovascular Disorders Oct 2020To explore the lesion outline and thermal field distribution of radiofrequency ablation (RFA) and laser ablation (LA) in myocardial ablation in vitro. (Comparative Study)
Comparative Study
OBJECTIVES
To explore the lesion outline and thermal field distribution of radiofrequency ablation (RFA) and laser ablation (LA) in myocardial ablation in vitro.
MATERIALS AND METHODS
Twenty-four fresh porcine hearts were ablated with RFA or LA in vitro. The radiofrequency electrode or laser fiber and two parallel thermocouple probes were inserted into the myocardium under ultrasound guidance. The output power for RFA was 20 W/s and for LA was 5 W/s, and the total thermal energies were 1200 J, 2400 J, 3600 J, and 4800 J. The range of ablation lesions was measured, and temperature data were recorded simultaneously.
RESULTS
All coagulation zones were ellipsoidal with clear boundaries. The center of LA was carbonized more obviously than that of RFA. With the accumulation of thermal energy and the extended time, all the ablation lesions induced by both RFA and LA were enlarged. By comparing the increase in thermal energy between the two groups, both the short-axis diameter and the volume change showed significant differences between the 1200 J and 3600 J groups and between the 2400 J and 4800 J groups (all P < 0.05). Both the short-axis diameter and the volume of the coagulation necrosis zone formed by LA were always larger than those of RFA at the same accumulated thermal energy. The temperatures of the two thermocouple probes increased with each energy increment. At the same accumulated energy, the temperature of LA was much higher than that of RFA at the same point. The initial temperature increase at 0.5 cm of LA was rapid. The temperature reached 43 °C and the accumulated energy reached 1200 J after approximately 4 min. After that the temperature increased at a slower rate to 70 C. For the RFA at the point of 0.5 cm, the initial temperature increased rapidly to 30 °C with the same accumulated energy of 1200 J after only 1 min. In the range of 4800 J of accumulated thermal energy, only the temperature of LA at the point of 0.5 cm exceeded 60 °C when the energy reached approximately 3000 J.
CONCLUSIONS
Both RFA and LA were shown to be reliable methods for myocardial ablation. The lesion outline and thermal field distribution of RFA and LA should be considered when performing thermal ablation in the intramyocardial septum during hypertrophic obstructive cardiomyopathy.
Topics: Animals; Catheter Ablation; In Vitro Techniques; Laser Therapy; Myocardium; Sus scrofa; Temperature; Time Factors
PubMed: 33081697
DOI: 10.1186/s12872-020-01735-3 -
Nature Reviews. Gastroenterology &... Mar 2011Improvements in the sensitivity and quality of cross-sectional imaging have led to increasing numbers of patients being diagnosed with cystic lesions of the pancreas. In... (Review)
Review
Improvements in the sensitivity and quality of cross-sectional imaging have led to increasing numbers of patients being diagnosed with cystic lesions of the pancreas. In parallel, clinical, radiological, pathological and molecular studies have improved the systems for classifying these cysts. Patients with asymptomatic serous cystic neoplasms can be managed conservatively with regular monitoring; however, the clinical management of patients with intraductal papillary mucinous neoplasms and mucinous cystic neoplasms is far more challenging, as it is difficult to determine whether these lesions will progress to malignancy. Fortunately, prospective studies have helped to establish that proposed clinical and radiological criteria (the Sendai guidelines) can be used to guide the care of patients with cystic lesions of the pancreas. Despite this progress in imaging and clinical guidelines, sensitive and specific tests have not yet been developed that can reliably predict the histology and biological properties of a cystic lesion. Such biomarkers are urgently needed, as noninvasive precursors of pancreatic cancer are curable, while the vast majority of invasive pancreatic adenocarcinomas are not.
Topics: Adenocarcinoma; Disease Progression; Humans; Neoplasm Invasiveness; Pancreatic Cyst; Pancreatic Neoplasms; Precancerous Conditions
PubMed: 21383670
DOI: 10.1038/nrgastro.2011.2 -
Diagnostics (Basel, Switzerland) Jan 2022Patients with new-onset malignant spinal lesions often have an urgent need for local spine intervention and systemic therapy. For optimal management, it is crucial to...
Patients with new-onset malignant spinal lesions often have an urgent need for local spine intervention and systemic therapy. For optimal management, it is crucial to diagnose the underlying disease as quickly and reliably as possible. The aim of our current study was to determine the feasibility, sensitivity, specificity, and diagnostic certainty of complementary cytological evaluation of spinal lesions suspected of malignancy. In 44 patients, we performed histopathological biopsies and in parallel cytologic preparations from the malignant site. Cytological smears were prepared and stained for May-Grunwald and Giemsa. Bone biopsies were histopathologically analyzed according to the existing standard-of-care practices. In 42 of 44 cases (95%), a cytological sample was successfully obtained. In 40 cases (95.2%, Cohen's kappa: 0.77), the cytological diagnosis agreed with the histological diagnosis regarding the identification of a malignant lesion. This resulted in a sensitivity of 97% and a specificity of 80% as well as a diagnostic safety of 95%. Cytological analysis in the context of spinal surgery proved sufficient to establish a diagnosis of malignancy or its exclusion, expanding the existing diagnostic spectrum. Furthermore, implementation of this process as a routine clinical diagnostic might shorten the time to diagnosis and improve the treatment of this vulnerable patient group.
PubMed: 35204401
DOI: 10.3390/diagnostics12020310 -
Ocular Oncology and Pathology Sep 2021To report retinal function findings on the choroidal nevus.
PURPOSE
To report retinal function findings on the choroidal nevus.
METHODS
Prospective descriptive case series of 7 patients ( = 7 eyes) presenting a melanocytic choroidal lesion consistent with choroidal nevus and no other ocular disease. Baseline evaluation included measurement of best-corrected visual acuity (BCVA), color and near-infrared fundus pictures, and spectral-domain OCT (Heidelberg Engineering). Retinal function was tested with microperimetry (MAIA; CenterVUE, Padova) using a standard grid (µP1) and a linear grid (µP2) that distribute test points on retinal areas that overlaid the choroidal lesion as well as lesion-free areas equidistantly to the fovea in 3 parallel lines. mfERG was performed following the International Society for Clinical Electrophysiology of Vision (ISCEV) recommendation using a 61-hexyagon protocol.
RESULTS
BCVA was 20/25 (0.1 logMAR) or better in all 7 eyes. Microperimetry showed central stable fixation on all eyes, with mean ± SE sensitivity threshold significantly decreased on retinal areas overlaying the lesions (µP1): 21.8 ± 0.6 dB versus 25.2 ± 0.9 dB on nonaffected retinal areas ( < 0.001). Sensitivity was also decreased on µP2: 23.7 ± 0.2 dB for areas overlying the nevi and 25.7 ± 0.3 dB for the nonaffected retina ( < 0.001). mfERG responses showed no focal amplitude or implicit-time changes on the retina in the topographical region corresponding to the nevus for all patients.
CONCLUSION
Our results indicate that choroidal nevi may cause significant retinal sensitivity impairment, as shown by microperimetry, but preserved mfERG response indicates that the retinal function may be only partially impaired.
PubMed: 34604202
DOI: 10.1159/000515561