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1.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 43(4): 642-648, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34494538

RESUMO

Arterial spin labeling is a noninvasive,quantitative method for perfusion imaging,which does not need any contrast media.This technique has been used in the renal perfusion analysis.In this article,we briefly introduced this technique and summarized its application in healthy volunteers,acute kidney injury,chronic kidney diseases,renovascular diseases,renal tumors,and renal transplantation.


Assuntos
Rim , Insuficiência Renal Crônica , Humanos , Rim/diagnóstico por imagem , Imageamento por Ressonância Magnética , Perfusão , Imagem de Perfusão , Marcadores de Spin
2.
J Agric Food Chem ; 69(33): 9642-9653, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34382782

RESUMO

Radical formation in isohumulones was investigated under different types of stress, including temperature, transition metal ions, and hydrogen peroxide. Including dihydroisohumulones and tetrahydroisohumulones, as relevant analogues, allowed us to evaluate critical functionalities in radical formation. Using spin-trapping methodology with 5,5-dimethyl-1-pyrroline N-oxide and N-tert-butyl-α-phenylnitrone as relevant traps, followed by simulation of corresponding spin adducts, identification of incipient radicals was attempted. The isohexenoyl side chain in isohumulones, but not present in dihydro- and tetrahydroisohumulones, was most sensitive to radical formation. Kinetic profiles further demonstrated that radical formation in this moiety was accelerated in the presence of ferrous ions. Reactivity of parent six-membered-ring humulones in radical formation was different, as scavenging of free radical species was more important. Lupulones, despite similarity with humulones, showed a different behavior with an obvious radical decay pathway during ageing, mainly ascribed to radical formation on the ring structure. Quantification of final spin adducts allowed us to determine absolute importance of the different degradation pathways. Eventually, mechanisms are presented explaining why isohumulones are more prone to radical processes in (aut)oxidation and thermal decay than close relatives such as dihydroisohumulones.


Assuntos
Ácidos , Óxidos N-Cíclicos , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres , Oxirredução , Marcadores de Spin , Detecção de Spin
3.
J Headache Pain ; 22(1): 91, 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34384347

RESUMO

BACKGROUND: Cluster headache is an excruciating disorder with no cure. Greater occipital nerve blockades can transiently suppress attacks in approximately 50% of patients, however, its mechanism of action remains uncertain, and there are no reliable predictors of treatment response. To address this, we investigated the effect of occipital nerve blockade on regional cerebral blood flow (rCBF), an index of brain activity, and differences between treatment responders and non-responders. Finally, we compared baseline perfusion maps from patients to a matched group of healthy controls. METHODS: 21 male, treatment-naive patients were recruited while in a cluster headache bout. During a pain-free phase between headaches, patients underwent pseudo-continuous arterial spin labelled MRI assessments to provide quantitative indices of rCBF. MRIs were performed prior to and 7-to-21 days following treatment. Patients also recorded the frequency of their headache attacks in a daily paper diary. Neuropsychological assessment including anxiety, depression and quality of life measures was performed in a first, scanning free session for each patient. RESULTS: Following treatment, patients demonstrated relative rCBF reductions in posterior temporal gyrus, cerebellum and caudate, and rCBF increases in occipital cortex. Responders demonstrated relative rCBF increases, compared to non-responders, in medial prefrontal cortex and lateral occipital cortex at baseline, but relative reductions in cingulate and middle temporal cortices. rCBF was increased in patients compared to healthy controls in cerebellum and hippocampus, but reduced in orbitofrontal cortex, insula and middle temporal gyrus. CONCLUSIONS: We provide new mechanistic insights regarding the aetiology of cluster headache, the mechanisms of action of occipital nerve blockades and potential predictors of treatment response. Future investigation should determine whether observed effects are reproducible and extend to other headache disorders.


Assuntos
Cefaleia Histamínica , Bloqueio Nervoso , Circulação Cerebrovascular , Cefaleia Histamínica/diagnóstico por imagem , Cefaleia Histamínica/terapia , Humanos , Masculino , Qualidade de Vida , Fluxo Sanguíneo Regional , Marcadores de Spin
4.
J Phys Chem B ; 125(27): 7380-7387, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34213354

RESUMO

Soluble stable radicals are used as spin probes and spin labels for in vitro and in vivo electron paramagnetic resonance (EPR) spectroscopy and imaging applications. We report the synthesis and characterization of a perchlorinated triarylmethyl radical enriched 99% at the central carbon, 13C1-PTMTC. The anisotropy of the hyperfine splitting with the 13C1 (Ax = 26, Ay = 25, Az = 199.5 MHz) and the g (gx = 2.0015, gy = 2.0015, gz = 2.0040) are responsible for a strong effect of the radical tumbling rate on the EPR spectrum. The rotational correlation time can be determined by spectral simulation or via the line width or the apparent Az after calibration, so the spin probe 13C1-PTMTC can be used to measure media microviscosity with high sensitivity.


Assuntos
Carbono , Espectroscopia de Ressonância de Spin Eletrônica , Marcadores de Spin
5.
Int J Mol Sci ; 22(13)2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34206765

RESUMO

A [H2DPEphos][MnX4] [X = Br, Cl] tetrahalomanganates(II) with P,P'-diprotonated bis[2-(diphenylphosphino)phenyl]ether cation has been designed and investigated in photophysics and EPR terms. The complexes exhibit a green luminescence resulted from the Mn(II) d-d transitions (4T1→6A1) with the wavelength-excitation dependence of the quantum yield. The solid [H2DPEphos][MnBr4] complex exhibits a bright green phosphorescence (λmax = 515 nm) with the high luminescence quantum yield depending on the excitation energy whereas the solid [H2DPEphos][MnCl4] complex exhibits a very weak phosphorescence (λmax = 523 nm). The unexpected shorter luminescence lifetime for the [H2DPEphos][MnCl4] than for the [H2DPEphos][MnBr4] at 300 K can be a result of the higher non-radiative relaxation contribution. On the one hand, the non-covalent PH…X(Mn) interactions quench the manganese(II) luminescence. On the other hand, the PH…X(Mn) interactions are a pathway of the excitation transfer from [H2DPEphos]2+ to [MnX4]2-.


Assuntos
Substâncias Luminescentes/química , Compostos de Manganês/química , Marcadores de Spin , Absorção de Radiação , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Prótons , Raios Ultravioleta
6.
J Headache Pain ; 22(1): 72, 2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34261444

RESUMO

BACKGROUND: Migraine constitutes a global health burden, and its pathophysiology is not well-understood; research evaluating cerebral perfusion and altered blood flow between brain areas using non-invasive imaging techniques, such as arterial spin labeling, have been scarce. This study aimed to assess cerebral blood flow (CBF) and its connectivity of migraine. METHODS: This study enrolled 40 patients with episodic migraine without aura (MwoA), as well as 42 healthy patients as control (HC). Two groups of normalized CBF and CBF connectivity were compared, and the relationship between CBF variation and clinical scale assessment was further evaluated. RESULTS: In comparison to HC subjects, MwoA patients exhibited higher CBF in the right middle frontal orbital gyrus (ORBmid.R) and the right middle frontal gyrus, while that in Vermis_6 declined. The increased CBF of ORBmid.R was positively correlated with both the Visual Light Sensitivity Questionnaire-8 (VLSQ-8) and the monthly attack frequency score. In MwoA, significantly decreased CBF connectivity was detected between ORBmid.R and the left superior frontal gyrus, the right putamen, the right caudate, as well as the right angular gyrus. In addition, increased CBF connectivity was observed between the left calcarine cortex and ORBmid.R. CONCLUSIONS: Our results indicate that migraine patients exhibit abnormalities in regional CBF and feature CBF connection defects at the resting state. The affected areas involve information perception, information integration, and emotional, pain and visual processing. Our findings might provide important clues for the pathophysiology of migraine.


Assuntos
Mapeamento Encefálico , Epilepsia , Encéfalo , Circulação Cerebrovascular , Humanos , Imageamento por Ressonância Magnética , Marcadores de Spin
7.
Int J Mol Sci ; 22(13)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34281176

RESUMO

Multicomponent reactions, especially the Ugi-four component reaction (U-4CR), provide powerful protocols to efficiently access compounds having potent biological and pharmacological effects. Thus, a diverse library of betulinic acid (BA), fusidic acid (FA), cholic acid (CA) conjugates with TEMPO (nitroxide) have been prepared using this approach, which also makes them applicable in electron paramagnetic resonance (EPR) spectroscopy. Moreover, convertible amide modified spin-labelled fusidic acid derivatives were selected for post-Ugi modification utilizing a wide range of reaction conditions which kept the paramagnetic center intact. The nitroxide labelled betulinic acid analogue 6 possesses cytotoxic effects towards two investigated cell lines: prostate cancer PC3 (IC50 7.4 ± 0.7 µM) and colon cancer HT29 (IC50 9.0 ± 0.4 µM). Notably, spin-labelled fusidic acid derivative 8 acts strongly against these two cancer cell lines (PC3: IC50 6.0 ± 1.1 µM; HT29: IC50 7.4 ± 0.6 µM). Additionally, another fusidic acid analogue 9 was also found to be active towards HT29 with IC50 7.0 ± 0.3 µM (CV). Studies on the mode of action revealed that compound 8 increased the level of caspase-3 significantly which clearly indicates induction of apoptosis by activation of the caspase pathway. Furthermore, the exclusive mitochondria targeting of compound 18 was successfully achieved, since mitochondria are the major source of ROS generation.


Assuntos
Óxidos N-Cíclicos/química , Bibliotecas de Moléculas Pequenas/síntese química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Ácido Cólico/química , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Ácido Fusídico/química , Humanos , Neoplasias/tratamento farmacológico , Triterpenos Pentacíclicos/química , Marcadores de Spin , Esteroides/farmacologia , Triterpenos/farmacologia
8.
Biophys J ; 120(13): 2679-2690, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34087213

RESUMO

Spin labels based on cinobufagin, a specific inhibitor of the Na,K-ATPase, have proved valuable tools to characterize the binding site of cardiotonic steroids (CTSs), which also constitutes the extracellular cation pathway. Because existing literature suggests variations in the physiological responses caused by binding of different CTSs, we extended the original set of spin-labeled inhibitors to the more potent bufalin derivatives. Positioning of the spin labels within the Na,K-ATPase site was defined and visualized by molecular docking. Although the original cinobufagin labels exhibited lower affinity, continuous-wave electron paramagnetic resonance spectra of spin-labeled bufalins and cinobufagins revealed a high degree of pairwise similarity, implying that these two types of CTS bind in the same way. Further analysis of the spectral lineshapes of bound spin labels was performed with emphasis on their structure (PROXYL vs. TEMPO), as well as length and rigidity of the linkers. For comparable structures, the dynamic flexibility increased in parallel with linker length, with the longest linker placing the spin label at the entrance to the binding site. Temperature-related changes in spectral lineshapes indicate that six-membered nitroxide rings undergo boat-chair transitions, showing that the binding-site cross section can accommodate the accompanying changes in methyl-group orientation. D2O-electron spin echo envelope modulation in pulse-electron paramagnetic resonance measurements revealed high water accessibilities and similar polarity profiles for all bound spin labels, implying that the vestibule leading to steroid-binding site and cation-binding sites is relatively wide and water-filled.


Assuntos
ATPase Trocadora de Sódio-Potássio , Água , Sítios de Ligação , Espectroscopia de Ressonância de Spin Eletrônica , Simulação de Acoplamento Molecular , ATPase Trocadora de Sódio-Potássio/metabolismo , Marcadores de Spin
9.
J Neural Eng ; 18(4)2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-34087805

RESUMO

Objective. Semantic verbal fluency (SFV) is a cognitive process that engages and modulates specific brain areas related to language comprehension and production, decision making, response inhibition, and memory retrieval. The impairment of the brain network responsible for these functions is related to various neurological conditions, and different strategies have been proposed to assess SVF-related deficits in such diseases. In the present study, the concomitant changes of brain perfusion and functional connectivity were investigated during the resting state and SVF task performance.Approach. Arterial spin labeling (ASL), a perfusion-based magnetic resonance imaging (MRI) method, was used with a pseudocontinuous labeling approach and dual-echo readout in 28 healthy right-handed Brazilian Portuguese speakers. The acquisition was performed in a resting state condition and during the performance of a SVF task.Main results. During task performance, a significant increase in cerebral blood flow (CBF) was observed in language-related regions of the frontal lobe, including Brodmann's areas 6, 9, 45, and 47, associated with semantic processing, word retrieval, and speech motor programming. Such regions, along with the posterior cingulate, showed a crucial role in the SVF functional network, assessed by seed-to-voxel and graph analysis. Our approach successfully overcame the generalization problem regarding functional MRI (fMRI) graph analysis with cognitive, task-based paradigms. Moreover, the CBF maps enabled the functional assessment of orbital frontal and temporal regions commonly affected by magnetic susceptibility artifacts in conventional T2*-weighted fMRI approaches.Significance. Our results demonstrated the capability of ASL to evaluate perfusion alterations and functional patterns simultaneously regarding the SVF network providing a quantitative physiological basis to functional hubs in this network, which may support future clinical studies.


Assuntos
Mapeamento Encefálico , Semântica , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular , Imageamento por Ressonância Magnética , Marcadores de Spin
10.
Science ; 373(6551): 236-241, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34083449

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of COVID-19, uses an RNA-dependent RNA polymerase (RdRp) for the replication of its genome and the transcription of its genes. We found that the catalytic subunit of the RdRp, nsp12, ligates two iron-sulfur metal cofactors in sites that were modeled as zinc centers in the available cryo-electron microscopy structures of the RdRp complex. These metal binding sites are essential for replication and for interaction with the viral helicase. Oxidation of the clusters by the stable nitroxide TEMPOL caused their disassembly, potently inhibited the RdRp, and blocked SARS-CoV-2 replication in cell culture. These iron-sulfur clusters thus serve as cofactors for the SARS-CoV-2 RdRp and are targets for therapy of COVID-19.


Assuntos
Coenzimas/metabolismo , RNA-Polimerase RNA-Dependente de Coronavírus/antagonistas & inibidores , RNA-Polimerase RNA-Dependente de Coronavírus/química , Óxidos N-Cíclicos/farmacologia , Ferro/metabolismo , SARS-CoV-2/efeitos dos fármacos , Enxofre/metabolismo , Motivos de Aminoácidos , Animais , Antivirais/farmacologia , Sítios de Ligação , Domínio Catalítico , Chlorocebus aethiops , Coenzimas/química , RNA-Polimerase RNA-Dependente de Coronavírus/metabolismo , Inibidores Enzimáticos/farmacologia , Ferro/química , Domínios Proteicos , RNA Helicases/metabolismo , SARS-CoV-2/enzimologia , SARS-CoV-2/fisiologia , Marcadores de Spin , Enxofre/química , Células Vero , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/efeitos dos fármacos , Zinco/metabolismo
11.
J Stroke Cerebrovasc Dis ; 30(8): 105885, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34107416

RESUMO

BACKGROUND: Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique used to quantify cerebral blood perfusion by labeling blood water as it flows throughout the brain. Hypoperfusion volume ratio (HVR) can be calculated using proportional hypoperfusion volume on ASL-based cerebral blood flow (CBF). This study aimed to explore the relation between HVR and early neurological deterioration (END) in AIS patients. SUBJECTS AND METHODS: Patients with AIS were recruited consecutively, and ASL and regular MRI scans were performed. HVR was calculated from 1.5 and 2.5s post labeling delay (PLD) ASL-CBF maps. END was defined as ≥2 points increment of NIHSS within 72 hours of stroke onset. Univariate and multivariate analysis were used to evaluate the relation between HVR and END. Receiver operating characteristic (ROC) curves were used to determine the ability of HVR in predicting END. RESULTS: Of the 52 enrolled patients, 18 (34.5%) were determined with END. In patients with END, the median hypoperfusion volume was 20 mL [Inter Quartile Range)IQR, 6-72.5 mL] at 1.5s PLD, and 11.2 mL (IQR, 5.3-26 mL) at 2.5s PLD; Sixteen (88.9%) patients had HVR ≥50%, and 13 (72.2%) patients hypoperfusion volume at 2.5s PLD ASL were greater than diffusion-weighted imaging (DWI) infarct volume. In patients without END, median hypoperfusion volume was 7 mL (IQR, 4-30 mL) at 1.5s PLD, and 4 mL (IQR, 1.5-8.5 mL) at 2.5s; Eleven (32.4%) patients had HVR ≥50%, and 10 (29.4%) patients hypoperfusion volume at 2.5s PLD ASL were greater than DWI infarct volume. The proportion of HVR ≥50% and hypoperfusion volume >DWI infarct volume were more frequent in patients with END than patients without (all P<0.001). After adjusted for age, admission NIHSS, proportion of hypoperfusion volume > DWI infarct and arterial transit artifact (ATA) by logistic regression analysis, HVR ≥50% (OR=13.1, P=0.003) was an independent risk factor for END. ROC analysis demonstrated that the HVR could predict END with an area under the curve of 0.794 (P=0.001). CONCLUSIONS: HVR obtained from the 1.5 and 2.5s PLD ASL may be a useful predictor of END in AIS. The value of HVR may be a marker for hemodynamic impairments.


Assuntos
Encéfalo/irrigação sanguínea , Circulação Cerebrovascular , AVC Isquêmico/diagnóstico por imagem , Imageamento por Ressonância Magnética , Imagem de Perfusão , Marcadores de Spin , Idoso , Avaliação da Deficiência , Progressão da Doença , Feminino , Estado Funcional , Humanos , AVC Isquêmico/fisiopatologia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Fluxo Sanguíneo Regional , Medição de Risco , Fatores de Risco
12.
Molecules ; 26(9)2021 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-34066858

RESUMO

Alterations in viscosity of biological fluids and tissues play an important role in health and diseases. It has been demonstrated that the electron paramagnetic resonance (EPR) spectrum of a 13C-labeled trityl spin probe (13C-dFT) is highly sensitive to the local viscosity of its microenvironment. In the present study, we demonstrate that X-band (9.5 GHz) EPR viscometry using 13C-dFT provides a simple tool to accurately measure the microviscosity of human blood in microliter volumes obtained from healthy volunteers. An application of low-field L-band (1.2 GHz) EPR with a penetration depth of 1-2 cm allowed for microviscosity measurements using 13C-dFT in the living tissues from isolated organs and in vivo in anesthetized mice. In summary, this study demonstrates that EPR viscometry using a 13C-dFT probe can be used to noninvasively and rapidly measure the microviscosity of blood and interstitial fluids in living tissues and potentially to evaluate this biophysical marker of microenvironment under various physiological and pathological conditions in preclinical and clinical settings.


Assuntos
Viscosidade Sanguínea , Isótopos de Carbono/química , Líquido Extracelular/química , Marcadores de Spin , Compostos de Tritil/química , Animais , Espectroscopia de Ressonância de Spin Eletrônica , Feminino , Voluntários Saudáveis , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Viscosidade
13.
Acta Neurochir Suppl ; 128: 113-119, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34191067

RESUMO

OBJECTIVE: This study evaluated the usefulness of arterial spin labeling (ASL) for assessment of tumor blood flow (TBF) and cerebral blood flow (CBF) before Gamma Knife surgery (GKS) for intracranial metastases, in order to analyze the variability of perfusion characteristics at baseline and to reveal how these data may impact differentiation of radiation-induced effects from tumor progression during follow-up. METHODS: Radiological data from 87 patients with intracranial metastases of solid cancers, who underwent TBF/CBF analysis by means of ASL at the Hawaii Advanced Imaging Institute between 2015 and 2018 both before and after GKS, were reviewed retrospectively. Only cases with a largest tumor diameter of ≥10 mm were included in the study cohort (N = 53). RESULTS: In comparison with CBF in the healthy contralateral cerebral cortex, TBF before GKS was greater in 32 cases (60%), lesser in 7 cases (13%), and equivalent in 14 cases (27%). There was significant variability in TBF both within and between histologically different groups of tumors. CONCLUSION: Since, at baseline, approximately 40% of intracranial metastases have TBF that is lesser or equivalent to CBF, increased blood flow in the contrast-enhancing lesion after GKS may have insufficient sensitivity for identification of tumor progression. Availability of baseline TBF data may significantly facilitate differential diagnosis in such cases.


Assuntos
Neoplasias Encefálicas , Radiocirurgia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/cirurgia , Humanos , Imageamento por Ressonância Magnética , Necrose , Estudos Retrospectivos , Marcadores de Spin
14.
Zhonghua Yi Xue Za Zhi ; 101(23): 1772-1777, 2021 Jun 22.
Artigo em Chinês | MEDLINE | ID: mdl-34167276

RESUMO

Objective: To investigate the use of deep learning approaches to improve the image quality of arterial spin labeling (ASL) and optimize its quantitative accuracy for cerebral blood flow (CBF). Methods: The clinical and imaging data of 101 patients with cerebrovascular disease in Tianjin Huanhu Hospital from May 2018 to August 2019 were retrospectively collected. Patients were divided into a training set (71 cases) and a validation set (30 cases). In training set, there were 53 cases of male,18 cases of female,with age of 55.0 (41.3, 64.5), and in validation set, there were 23 cases of male,7 cases of female,with age of57.5 (49.0, 65.0). Quantitative perfusion weighted imaging was used as the reference standard, and the original ASL-CBF images were reconstructed by training a deep learning generative adversarial network (GAN). The image quality of original ASL-CBF and GAN-CBF was compared by the structural similarity index and the normalized root mean square error. Pearson correlation coefficient was used to analyze the correlation between ASL-CBF, GAN-CBF and quantitative perfusion in different cerebral vascular blood supply areas and stroke areas, and to verify the improvement effect of GAN on the image quality and quantitative accuracy of ASL. Results: There were significant differences in gender, age, disease type, site and size between training set and validation set (all P>0.05). Compared with ASL-CBF, GAN-CBF had a higher structural similarity index (0.888 vs 0.801, P<0.001), and a lower normalized root mean square error (0.628 vs 0.775, P<0.001). The correlation between GAN-CBF and quantitative perfusion in different blood vessel supply areas and stroke lesion areas was improved compared with the original ASL-CBF, in which the perforating branch of the middle artery (r=0.853) and stroke lesion areas (r=0.765) were the most obvious (all P<0.001). Conclusion: The generative adversarial network could improve the image quality and quantization accuracy of ASL without increasing the scanning time, and expand the clinical application value of ASL.


Assuntos
Circulação Cerebrovascular , Imageamento por Ressonância Magnética , Artérias , Feminino , Humanos , Masculino , Estudos Retrospectivos , Marcadores de Spin
15.
Zhonghua Yi Xue Za Zhi ; 101(23): 1778-1783, 2021 Jun 22.
Artigo em Chinês | MEDLINE | ID: mdl-34167277

RESUMO

Objective: To explore the correlation between decreased cerebral perfusion measured from arterial spin labeling and cerebrovascular events in patients with bilateral moyamoya angiography (MMA). Methods: Twenty-seven consecutive cases with bilateral MMA, who were admitted to the neurosurgery department of Nanjing Drum Tower Hospital from April to November 2020, were included in this retrospective study. Among them, 10 were males and 17 were females, aged 35-66 (55±9) years. These patients all presented with unilateral cerebral hemisphere cerebral infarction or cerebral hemorrhage. The Wilcoxon paired signed-rank test was used to qualitatively analyze the differences in the Arterial Transit Artifact (ATA) of the bilateral cerebral hemispheres. The mean gray value, the kurtosis and skewness of gray distribution curve of bilateral cerebral hemispheres on cerebral blood flow (CBF) images with post labeling delay (PLD) of 1.5 s and 2.5 s were quantitative calculated. The relationship between ASL and cerebrovascular event was determined using binary logistics regression analysis. Results: No significant difference was observed in ATA between bilateral hemispheres on CBF images with PLDs of 1.5 s and 2.5 s (P>0.05). On the CBF images with a PLD of 1.5 s, the mean gray value of the cerebral hemisphere on the lesion side (17.50±5.88) was markly lower than that on the non-lesion side (20.80±5.51) (P<0.001), the kurtosis and skewness of gray distribution were significantly different between bilateral cerebral hemispheres (P<0.05);On the CBF images with a PLD of 2.5 s, the mean gray value and the skewness of the gray distribution on the lesion side of the cerebral hemisphere were statistically different from those on the non-lesion side (P<0.05), while the difference in kurtosis was not statistically significant between bilateral cerebral hemispheres (P>0.05). Multivariate regression analysis showed that the reduction of gray value on the side of the lesion was independently associated to the occurrence of the cerebrovascular events (ORPLD1.5=0.192, 95%CI:0.047-0.783;ORPLD2.5=0.175, 95%CI:0.050-0.615). Conclusion: The decreased perfusion detected by ASL is independently associated with cerebrovascular events in patients with MMA.


Assuntos
Doença de Moyamoya , Circulação Cerebrovascular , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Doença de Moyamoya/diagnóstico por imagem , Perfusão , Estudos Retrospectivos , Marcadores de Spin
16.
Zhonghua Yi Xue Za Zhi ; 101(23): 1784-1790, 2021 Jun 22.
Artigo em Chinês | MEDLINE | ID: mdl-34167278

RESUMO

Objective: To compare the cerebral perfusion differences between the symptomatic patients and the asymptomatic patients with unilateral middle cerebral artery (MCA) severe stenosis or occlusion by using three post labeling delays (PLD) of the three-dimensional pseudo-continuous arterial spin labeling (pCASL) technique. Methods: The clinical characteristics and ASL data of the 27 patients with severe stenosis or occlusion of unilateral MCA (18 symptomatic, 9 asymptomatic) were prospectively enrolled from April 2018 to November 2019 in the Department of Radiology of China-Japan Friendship Hospital. There were 16 males and 11 females, age range from 29 to 85 (55±13) years. According to the symptoms, they were divided into symptomatic group (18 cases) and asymptomatic group (9 cases). The parameters of cerebral blood flow (CBF), mean cerebral blood flow (mCBF), arterial transit time (ATT) and arterial cerebral blood volume (aCBV) were obtained using the Cereflow software. One-way multivariate analysis of variance (one-way MANOVA) was used to compare the differences of cerebral perfusion parameters between symptomatic group and asymptomatic group, and between the affected side and the control side in the two groups. Two-way ANOVA was used to evaluate the effects of symptoms, hemisphere (affected and control side), PLD times (1.5, 2.0 and 2.5 s) and the interaction between the two factors. Results: The CBF of the affected leptomeningeal branch and perforating branch of MCA in symptomatic group was lower than that in asymptomatic group [(36.8±10.2) ml·100 g-1·min-1 versus (46.6±13.9) ml·100 g-1·min-1, F(1, 75)=13.279, P=0.000 49; (32.3±8.3) ml·100 g-1·min-1 versus (36.2±7.5) ml·100 g-1·min-1, F (1, 75)=4.065, P=0.047], and there was no interaction between the symptom and PLD [F(2, 75) =0.061, P=0.940]. In the symptomatic group, the CBF of the leptomeningeal branch and perforating branch of MCA in affected side was lower than that in control side [(36.8±10.2) ml·100 g-1·min-1 versus (43.7±10.0) ml·100 g-1·min-1, F(1, 102)=12.559, P=0.000 59; (32.3±8.3) ml·100 g-1·min-1 versus (36.4±8.0) ml·100 g-1·min-1, F(1, 102)=6.493, P=0.012]. In the symptomatic group, the CBF of leptomeningeal branch of MCA when PLD was 2.5 s was 7.34 ml·100 g-1·min-1, which were higher than that when PLD of 1.5 s (95%CI: 0.72-13.9, P=0.03). There was no interaction between PLD and hemisphere [F(2, 102) =0.307, P=0.736]. Conclusions: The collateral circulation in the blood supply area of MCA in asymptomatic patients with severe unilateral MCA stenosis or occlusion is more abundant than that in symptomatic patients. ASL can be an effective technique for evaluating the cerebral perfusion of collateral circulation in patients with severe stenosis or occlusion of MCA.


Assuntos
Imageamento por Ressonância Magnética , Artéria Cerebral Média , Adulto , Idoso , Idoso de 80 Anos ou mais , Circulação Cerebrovascular , China , Constrição Patológica , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Marcadores de Spin
17.
Zhonghua Yi Xue Za Zhi ; 101(23): 1791-1797, 2021 Jun 22.
Artigo em Chinês | MEDLINE | ID: mdl-34167279

RESUMO

Objective: To evaluate the diagnostic performance of the combination of arterial spin labeling (ASL) and time of flight MR angiography (TOF MRA) for intracranial arteriovenous shunt (AVS) detection. Methods: A total of 39 patients with known or suspected with cerebrovascular malformations underwent digital subtraction angiography (DSA) and ASL/TOF MRA imaging in Department of neurosurgery and radiology and nuclear medicine, Xuanwu Hospital from May 1, 2020 to October 31, 2020 were retrospectively analyzed. Patients were divided into either acute cerebral hemorrhage group (n=13) or non-acute cerebral hemorrhage group (n=26) based on the signs of bleeding on imaging findings. According to history of treatment, those patients were divided into treated (n=11) and untreated (n=28) subgroups. The determination of the presence of AVS on images was judged by two radiologists in a blinded and randomized order fashion. The diagnostic performance of ASL or TOF MRA for AVS were evaluated in overall, acute cerebral hemorrhage subgroup and treated subgroup by using the area under receiver operating curve (AUC) with DSA as the reference standard, respectively. The κ coefficients were calculated to determine the interobserver agreement. Results: Among 39 patients, 29 patients were confirmed with AVS by DSA while 10 patients with no AVS. Interobserver agreement was good-excellent (κ=0.83-1.00). In patients with AVM, the detection rates for AVS of ASL or TOF MRA were 93.1% and 86.2% respectively, while the detection rates of the combination of ASL and TOF MRA were 100%. The AUC of ASL, TOF MRA and their combination for diagnosis of AVS in overall were 0.966 (95%CI: 0.909-1.00), 0.914 (95%CI: 0.825-1.00) and 0.983 (95%CI:0.943-1.00), respectively. The AUC of ASL, TOF MRA and their combination for AVS in acute cerebral hemorrhage subgroup were 1(95%CI:1.00-1.00), 0.833(95%CI:0.611-1.00), 1(95%CI:1.00-1.00), respectively. Conclusion: Combination of ASL and TOF MRA can be a non-invasive thchnique for the detection of AVS.


Assuntos
Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética , Angiografia Digital , Humanos , Estudos Retrospectivos , Sensibilidade e Especificidade , Marcadores de Spin
18.
J Agric Food Chem ; 69(32): 9034-9042, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006112

RESUMO

The free-radical-mediated formation mechanism of polar polymeric triglycerides (TAGs) was derived based on the formation of lipid-derived radicals and the degradation of TAGs in palm oil (PO), rapeseed oil (RO), and sunflower oil (SO). The experimental spectra were simulated by alkoxyl, alkyl, and 5-dimethyl-1-pyrroline N-oxide (DMPO)-oxidized adducts. DMPO-oxidized adducts were the main radical adducts in the initial stage. Then, alkyl radical adducts became the dominating radical adducts after 12 min in PO and RO. The intensity of alkyl radical adducts was the highest in SO. Therefore, based on the bimolecular reaction, polar polymeric TAGs were mainly bonded by -C-O-O-C- in the initial stage and then by -C-C- and -C-O-C- after 30 min. Besides, according to the correlation analysis between the amounts of polar polymeric TAGs and the degradation of TAGs, the main structures of polar polymeric TAGs in PO, RO, and SO were POL-LOP, POL-OOP, and POO-OOP; OLL-LnLO, OLLn-OLnO, OOO-OLO, and OLLn-OOO; and LLL-LLO, LLL-LLL, and OLL-LLO, respectively.


Assuntos
Óxidos N-Cíclicos , Óleos Vegetais , Cromatografia Líquida de Alta Pressão , Espectroscopia de Ressonância de Spin Eletrônica , Radicais Livres , Marcadores de Spin , Detecção de Spin , Triglicerídeos
19.
Radiother Oncol ; 160: 97-106, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33951492

RESUMO

BACKGROUND AND PURPOSE: Chemoradiotherapy (CRT) has been widely applied in patients with advanced nasopharyngeal carcinoma (ANPC). However, limited imaging modality exists on the evaluation of early response to CRT. The purpose of this study was therefore to investigate whether 3D pseudo-continuous arterial spin labeling (3D pCASL) perfusion imaging could predict early response to CRT in ANPC patients. MATERIALS AND METHODS: Seventy ANPC patients who received CRT underwent pre-treatment MRI including 3D pCASL perfusion measurements, and were categorized into response group (RG) and no-response group (NRG) according to RECIST 1.1. Pre-treatment 3D pCASL derived cerebral blood flow (CBF) values in tumors were compared between RG and NRG patients. Receiver-operating characteristic (ROC) analysis was performed to determine the optimal diagnostic cutoff value for CBF in predicting tumor response to CRT. Clinicopathological variables were also analyzed by using univariate and binary logistic regression. The corresponding obtained variables with statistical significance were further applied to create a nomogram in which the bootstrap resampling method was used for calibration. RESULTS: Forty-eight patients in RG had significantly higher pre-treatment CBF values in tumors compared with 22 patients in NRG (P < 0.001). CBF showed the high area under the ROC curve (AUC = 0.843) in distinguishing RG from NRG patients. The corresponding cutoff value for CBF was 103.68 ml/100 g/min, with respective accuracy, sensitivity and specificity of 82.86%, 87.50% and 72.73%. The nomogram was generated by binary logistic regression results, incorporating three variables: CBF value, clinical stage and pathological type. The AUC, accuracy, sensitivity and specificity of the nomogram was respectively 0.893, 84.28%, 81.25% and 90.91% in predicting tumor response to CRT. Moreover, as shown in the calibration curve, a strong agreement was observed between nomogram prediction probability and actual clinical findings (P = 0.309). CONCLUSIONS: 3D pCASL derived CBF in tumor could act as a noninvasive effective biomarker to predict tumor response to CRT in ANPC patients before clinical treatment. Furthermore, the nomogram combining CBF and clinicopathological variables could serve as a novel clinical analysis tool for treatment response prediction.


Assuntos
Circulação Cerebrovascular , Neoplasias Nasofaríngeas , Quimiorradioterapia , Humanos , Imageamento por Ressonância Magnética , Carcinoma Nasofaríngeo/diagnóstico por imagem , Carcinoma Nasofaríngeo/terapia , Neoplasias Nasofaríngeas/diagnóstico por imagem , Neoplasias Nasofaríngeas/terapia , Perfusão , Imagem de Perfusão , Marcadores de Spin
20.
Magn Reson Med ; 86(4): 1917-1928, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33977546

RESUMO

PURPOSE: The ability to measure cerebral vascular compliance (VC) is important in the evaluation of vascular diseases. Additionally, quantification of arterial wall pulsation in the brain may be useful for understanding the driving force of the recently discovered glymphatic system. Our goal is to develop an MRI technique to measure VC and arterial wall pulsation in major intracranial vessels. METHODS: A total of 17 healthy subjects were studied on a 3T MRI system. The technique, called VaCom-PCASL, uses pseudo-continuous arterial spin labeling (PCASL) to obtain pure blood vessel signal, uses a 3D radial acquisition, and applies a golden-angle radial sparse parallel (GRASP) algorithm for image reconstruction. The k-space data were retrospectively sorted into different cardiac phases. The GRASP algorithm allows the reconstruction of 5D (three spatial dimensions, one control/label dimension, and one cardiac-phase dimension) data simultaneously. The proposed technique was optimized in terms of reconstruction parameters and labeling duration. Intracranial VC was compared with aortic pulse wave velocity measured with phase-contrast MRI. Age differences in VC were studied. RESULTS: The VaCom-PCASL technique using 10 cardiac phases and GRASP sparsity constraints of λlabel/control = 0.05 and λcardiac = 0.05 provided the highest contrast-to-noise ratio. A labeling duration of 800 ms was found to yield signals comparable to those of longer duration (P > .2), whereas 400 ms yielded significant overestimation (P < .005). A significant correlation was observed between intracranial VC and aortic pulse wave velocity (r = -0.73, P = .038, N = 8). Vascular compliance in the older group was lower than that in the younger group. CONCLUSION: The VaCom-PCASL-MRI technique represents a promising approach for noninvasive assessment of arterial stiffness and pulsatility.


Assuntos
Circulação Cerebrovascular , Análise de Onda de Pulso , Encéfalo , Humanos , Imageamento Tridimensional , Estudos Retrospectivos , Marcadores de Spin
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