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1.
Phys Chem Chem Phys ; 21(41): 22902-22909, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31595895

RESUMO

Broken-symmetry density functional calculations have been used to calculate effective 55Mn hyperfine (A) tensors for a mixed-valence tetranuclear manganese complex, a model system for the S2 state of the oxygen-evolving complex of photosystem II. Recent investigations carried out in our laboratory showed that for calculations within the strong exchange limit, density functional calculations cannot reproduce the relative magnitude of the anisotropy of the hyperfine tensors of the MnIII center compared to the MnIV centers. In this work we therefore go beyond the strong exchange limit and investigate the effect of multiplet mixing, induced by zero-field splitting, on the effective hyperfine tensors through a perturbational treatment within the numerical spin projection procedure. Results show that the inclusion of zero-field splitting leads to a shift of the anisotropy from the MnIII ion towards the three MnIV ions, thus reconciling the calculated and experimentally observed anisotropy pattern. However, the final results are quite sensitive to the energy gap between the ground (doublet) and the first excited (quartet) state and therefore critically depend on the appropriate choice of the isotropic exchange coupling constants.


Assuntos
Anisotropia , Modelos Biológicos , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema II , Manganês/química
2.
J Phys Chem Lett ; 10(20): 6105-6111, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31549842

RESUMO

Protein-protein interactions (PPIs) play a pivotal role in many biological processes. Discriminating functionally important well-defined protein-protein complexes formed by specific interactions from random aggregates produced by nonspecific interactions is therefore a critical capability. While there are many techniques which enable rapid screening of binding affinities in PPIs, there is no generic spectroscopic phenomenon which provides rapid characterization of the structure of protein-protein complexes. In this study we show that chiral plasmonic fields probe the structural order and hence the level of PPI specificity in a model antibody-antigen system. Using surface-immobilized Fab' fragments of polyclonal rabbit IgG antibodies with high specificity for bovine serum albumin (BSA), we show that chiral plasmonic fields can discriminate between a structurally anisotropic ensemble of BSA-Fab' complexes and random ovalbumin (OVA)-Fab' aggregates, demonstrating their potential as the basis of a useful proteomic technology for the initial rapid high-throughput screening of PPIs.


Assuntos
Fragmentos Fab das Imunoglobulinas/metabolismo , Imunoglobulina G/metabolismo , Nanoestruturas/química , Cimento de Policarboxilato/química , Soroalbumina Bovina/metabolismo , Animais , Anisotropia , Bovinos , Ouro/química , Fragmentos Fab das Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Ovalbumina/imunologia , Ovalbumina/metabolismo , Ligação Proteica , Coelhos , Soroalbumina Bovina/imunologia , Análise Espectral/métodos , Estereoisomerismo
3.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 44(7): 805-812, 2019 Jul 28.
Artigo em Chinês | MEDLINE | ID: mdl-31413220

RESUMO

OBJECTIVE: To evaluate the white-matter integrity and its correlation with cognitive function in patients with mild cognitive impairment (MCI) complicated with lacunar infarctions (LI) by diffusion tensor imaging (DTI) of magnetic resonance (MR).
 Methods: Twenty-six patients with MCI were selected including 14 patients with combined LI and 12 patients without combined LI, and 16 healthy volunteers were recruited as normal control. All subjects completed cognitive function assessment and DTI sequence of MR. Factional anisotropy (FA) and mean diffusivity (MD) values among the MCI with LI group (MCI-LI), the MCI without LI group (MCI-non LI), and the normal control group (NC) were compared, and the correlation between DTI parameters and cognition was determined by multiple linear stepwise regression.
 Results: Compared with the MCI-non LI group, the FA values were significantly decreased (P<0.05) and MD values were significantly increased (P<0.05) in the white matter fiber bundles (such as the left hippocampus of the cingulate tract, the frontal fascicle of the corpus callosum, the right inferior frontal occipital fascicle, and the right superior longitudinal fascicle) in the MCI-LI group. In the MCI-LI group, the FA value of right cingulate gyrus was significantly correlated with Activity of Daily Living Scale (ADL) score (B=-50.2, 95% CI -77.7 to -22.7, P=0.003); the FA value of left anterior thalamic radiation (B=443.8, 95% CI 222.9 to 664.8, P=0.001) and MD value of left inferior longitudinal tract (B=-318.5, 95% CI -534.7 to -102.3, P=0.009) were significantly correlated with Wechsler digit symbol substitution (WDSS) score; the FA value of left superior temporal lobe longitudinal tract was significantly correlated with Backward Digit Span (BDSP) score (B=12.5, 95% CI 1.5 to 23.4, P=0.030).
 Conclusion: The integrity of white matter is significantly destroyed in MCI patients with LI than that in MCI patients without LI, and there is a correlation between cognitive function and DTI parameters in some white matter tracts in MCI patients with LI.


Assuntos
Disfunção Cognitiva , Acidente Vascular Cerebral Lacunar , Substância Branca , Anisotropia , Encéfalo , Disfunção Cognitiva/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Humanos , Testes Neuropsicológicos
4.
Br J Radiol ; 92(1103): 20190324, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31386559

RESUMO

OBJECTIVE: This study was to investigate the relationship of diffusion features with molecule information, and then predict grade and survival in lower-grade gliomas. METHODS: 65 patients with primary lower-grade gliomas (WHO Grade II & III) who underwent conventional MRI and diffusion tensor imaging were retrospectively studied. The tumor region was automatically segmented into contrast-enhancing tumor, non-enhancing tumor, edematous and necrotic volumes. Diffusion features, including fractional anisotropy (FA), axial diffusivity, radial diffusivity and apparent diffusion coefficient (ADC), were extracted from each volume using histogram analysis. To estimate molecule biomarkers and predict clinical characteristics of grade and survival, support vector machine, generalized linear model, logistic regression and Cox regression were performed on the related features. RESULTS: The diffusion features in non-enhancing tumor volume showed differences between isocitrate dehydrogenase mutant and wild-type gliomas. And the mean accuracy of support vector machine classifiers was 0.79. Ki-67 labeling index was correlated with these features, which were combined to significantly estimate Ki-67 expression level (r = 0.657, p < 0.001). These features also showed differences between Grade II and III gliomas. A combination of them for grade classification resulted in an area under the curve of 0.914 (0.857-0.971). Mean FA and fifth percentile of ADC were independently associated with overall survival, with lower FA and higher ADC showing better survival outcome. CONCLUSION: In lower-grade gliomas, multiparametric and multiregional diffusion features could help predict molecule information, histological grade and survival. ADVANCES IN KNOWLEDGE: The multi parametric diffusion features in non-enhancing tumor were associated with molecule information, grade and survival in lower-grade gliomas.


Assuntos
Astrocitoma/patologia , Neoplasias Encefálicas/patologia , Oligodendroglioma/patologia , Adulto , Idoso , Anisotropia , Astrocitoma/mortalidade , Neoplasias Encefálicas/mortalidade , Imagem de Tensor de Difusão/métodos , Estudos de Viabilidade , Feminino , Humanos , Antígeno Ki-67/metabolismo , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Oligodendroglioma/mortalidade , Estudos Retrospectivos , Carga Tumoral , Adulto Jovem
5.
Comput Methods Biomech Biomed Engin ; 22(15): 1174-1185, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31423837

RESUMO

Prestretch is observed in many soft biological tissues, directly influencing the mechanical behavior of the tissue in question. The development of this prestretch occurs through complex growth and remodeling phenomena, which yet remain to be elucidated. In the present study it was investigated whether local cell-mediated traction forces can explain the development of global anisotropic tissue prestretch in the mitral valve. Towards this end, a model predicting actin stress fiber-generated traction forces was implemented in a finite element framework of the mitral valve. The overall predicted magnitude of prestretch induced valvular contraction after release of in vivo boundary constraints was in good agreement with data reported on valvular retraction after excision from the heart. Next, by using a systematic variation of model parameters and structural properties, a more anisotropic prestretch development in the valve could be obtained, which was also similar to physiological values. In conclusion, this study shows that cell-generated traction forces could explain prestretch magnitude and anisotropy in the mitral valve.


Assuntos
Valva Mitral/fisiopatologia , Modelos Cardiovasculares , Estresse Mecânico , Anisotropia , Fenômenos Biomecânicos , Simulação por Computador , Elasticidade , Análise de Elementos Finitos
6.
Comput Methods Biomech Biomed Engin ; 22(15): 1197-1208, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31432696

RESUMO

Despite the general interest in aneurysm rupture prediction, the aneurysm formation has received limited attention. The goal of this study is to assess whether an aneurysm may be instigated in a healthy model of an aorta inflated by a supra-physiological pressure. The effect of two main aspects on numerical predictions has been explored: i) the geometric design and ii) the constitutive law adopted to represent the material properties. Firstly, higher values of wall stress and displacement magnitude were generated in the physiologic model compared to the cylindrical one when assigning the same material properties. Secondly, greater deformations are observed in the anisotropic model compared to the isotropic one.


Assuntos
Aneurisma/fisiopatologia , Aorta Torácica/fisiopatologia , Análise de Elementos Finitos , Modelos Cardiovasculares , Anisotropia , Fenômenos Biomecânicos , Humanos , Pressão , Estresse Mecânico
7.
Artigo em Russo | MEDLINE | ID: mdl-31339493

RESUMO

Diffuse axonal injury (DAI) is one of the most severe traumatic brain injuries. The availability of neuroimaging biomarkers for monitoring expansion of traumatic brain injury in vivo is a topical issue. PURPOSE: To evaluate novel neuroimaging biomarkers for monitoring brain injury using diffusion kurtosis imaging (DKI) in patients with severe diffuse axonal injury. MATERIAL AND METHODS: DKI data of 12 patients with severe DAI (11 patients with a Glasgow Coma Scale (GCS) score of ≤ 8 and 1 patient with a GCS score of 9) and 8 healthy volunteers (control group) were compared. MRI examination was performed 5 to 19 days after injury; 7 of the 12 patients underwent repeated MRI examinations. We assessed the following parameters: mean, axial, and radial kurtosis (MK, AK, RK, respectively) and kurtosis anisotropy (KA) of the white and gray matter; fractional anisotropy (FA), axonal water fraction (AWF), axial and radial extra-axonal diffusion (AxEAD and RadEAD, respectively), and tortuosity (TORT) of the extra-axonal space) of the white matter. Regions of interest (ROIs) were set bilaterally in the centrum semiovale, genu and splenium of the corpus callosum, anterior and posterior limbs of the internal capsule, putamen, thalamus, midbrain, and pons. RESULTS: A significant reduction in KA (p<0.05) in most of ROIs set on the white matter was revealed. AK was increased (p<0.05) not only in the white matter but also in the putamen and thalamus. A significant reduction in MK with time was observed when the first and second DKI data were compared. AWF was reduced in the centrum semiovale and peduncles. The TORT parameter was decreased (p<0.05) in the majority of ROIs in the white matter, with the most pronounced changes occurring in the genu and splenium of the corpus callosum. CONCLUSION: DKI provides novel data about microstructural injury in DAI and improves our knowledge of brain trauma pathophysiology. DKI parameters should be considered as potential biomarkers of brain injury and potential predictors of the outcome.


Assuntos
Lesão Axonal Difusa , Substância Branca , Anisotropia , Lesão Axonal Difusa/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Humanos , Neuroimagem
8.
J Craniofac Surg ; 30(5): 1471-1474, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31299746

RESUMO

OBJECTIVE: The aim of this study is to assess the microstructural changes to the olfactory bulb (OB) in patients with nasal septum deviation (NSD) using diffusion tensor imaging and to research the association between these changes and the degree of NSD. METHODS: Ninety-six patients with NSD (46 males, 50 females) who received diffusion tensor imaging were assessed by 2 independent readers. The patients were separated into 3 groups according to the NSD angle. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the ipsilateral and contralateral OB were measured in all NSD patients by region of interest. RESULTS: According to deviation side, there was significant difference between the right (R) and left (L) OB FA and ADC values across the 3 groups. In patients with left- and right- sided NSD, FA and ADC values for the left and right OB were significantly different between groups 1 and 3, and groups 2 and 3. There was negative correlation between L-FA (r = -0.481, P = 0.001; r = -0.496, P = 0.001) and R-FA (r = -0.705, P = 0.001; r = -0.286, P = 0.02) versus age and deviation angle. However, there was positive correlation between L-ADC versus age and deviation angle (r = 0.493, P = 0.001; r = 0.482, P = 0.001), as well as positive correlation between R-ADC versus age (r = 0.646, P = 0.001). CONCLUSION: This is the first study showing ADC increase and FA decrease associated with axonal damage and microstructural integrity loss based on the side of deviation in NSD patients. It has also shown that this abnormality is directly proportional with NSD degree.


Assuntos
Septo Nasal/diagnóstico por imagem , Deformidades Adquiridas Nasais/diagnóstico por imagem , Bulbo Olfatório/diagnóstico por imagem , Adulto , Idoso , Anisotropia , Axônios , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
9.
Comput Biol Chem ; 82: 37-43, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31255973

RESUMO

Tubulin protein is the fundamental unit of microtubules, and comprises of α and ß subunits arranged in an alternate manner forming protofilaments. These longitudinal protofilaments are made up of intra- (α-ß) and inter-dimer (ß-α) interactions. Literature review confirms that GTP hydrolysis results in considerable structural rearrangement within GTP binding site of ß-α dimer interface after the release of γ phosphate. In addition to this, the intra-dimer interface exhibits structural rigidity which needs further investigation. In this study, we explored the reasons for the flexibility and the rigidity of the ß-α dimer and the α-ß dimer respectively through molecular simulation and Anisotropic Normal Mode based analysis. As per the sequence alignment report, two glycine residues (Gly96 and Gly98) were observed in the T3 loop of the ß subunit which get substituted by Asp98 and Ala100 in the T3 loop of the α subunit. The higher mobility of glycine residues contributes to the flexibility of the T3 loop of inter-dimer when they come in direct contact with the GTPase Activating Protein (GAP) domain of the subunit. This was confirmed through RMSD, RMSF and Radius of Gyration based studies. Conversely, the intra-dimer exhibited a lower mobility in the absence of glycine residues. As per ANM based analysis, positive domain correlations were observed between T3 loop and GAP domain of intra- and inter- dimeric contact regions. However, these correlation motions were higher in the intra-dimer as compared to the inter-dimer interface. Thus on the basis of our findings, we hypothesize that the higher flexibility of T3 loop and the GAP domain of the inter-dimer is required for structural rearrangement and protofilament stability during hydrolysis. Furthermore, the slightly rigid nature of the T3 loop and the GAP domain of the intra-dimer assists in enhancing the monomer-monomer interaction through the higher positive domain correlation.


Assuntos
Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo , Sequência de Aminoácidos , Animais , Anisotropia , Sítios de Ligação , Bovinos , Glicina/química , Simulação de Dinâmica Molecular , Mutação , Maleabilidade , Ligação Proteica , Conformação Proteica , Domínios Proteicos , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Multimerização Proteica , Alinhamento de Sequência , Tubulina (Proteína)/genética
10.
J Headache Pain ; 20(1): 78, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31291903

RESUMO

BACKGROUND: Several studies have investigated white matter with diffusion tensor imaging (DTI) in those suffering from headache, but so far only in clinic based samples and with conflicting results. METHODS: In the present study, 1006 individuals (50-66 years) from the general population (Nord-Trøndelag Health Study) participated in an imaging study of the head at 1.5 T (HUNT-MRI). Hundred and ninety-six individuals were excluded because of errors in the data acquisition or brain pathology. Two hundred and forty-six of the remaining participants reported suffering from headache (69 from migraine and 76 from tension-type headache) the year prior to the scanning. DTI data were analysed with Tract-Based Spatial Statistics and automated tractography. Type of headache, frequency of attacks and evolution of headache were investigated for an association with white matter fractional anisotropy (FA), mean diffusivity (MD), axonal diffusivity (AD), radial diffusivity (RD) and tract volume. Correction for various demographical and clinical variables were performed. RESULTS: Headache sufferers had widespread higher white matter MD, AD and RD compared to headache free individuals (n = 277). The effect sizes were mostly small with the largest seen in those with middle-age onset headache, who also had lower white matter FA. There were no associations between white matter microstructure and attack frequency or type of headache. CONCLUSION: Middle-age onset headache may be related to a widespread process in the white matter leading to altered microstructure.


Assuntos
Cefaleia/diagnóstico por imagem , Cefaleia/patologia , Transtornos de Enxaqueca/diagnóstico por imagem , Transtornos de Enxaqueca/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Adulto , Idoso , Anisotropia , Estudos Transversais , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
11.
Br J Radiol ; 92(1102): 20190133, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31322916

RESUMO

OBJECTIVE: Signal-to-noise ratio (SNR) assessment is essential for accurate quantification of diffusion tensor imaging (DTI) metrics and usually requires the use of a difference image method using duplicate images. We aimed to estimate the SNR of DTI of thigh muscles using a single image set without duplicate images. METHODS: DTI of one thigh were acquired on a 3 T scanner from 15 healthy adults, and scans with number of signal averages (NSA) = 4 and 8 were repeatedly acquired. SNR were evaluated for six thigh muscles. For SNR calculation from a single image set, diffusion-weighted images with similar diffusion encoding directions were grouped into pairs. The difference image of each pair was high-pass filtered in k-space to yield noise images. Noise images were also calculated with a difference method using two image sets as a reference. Subjects were divided into two groups for filter optimization and validation, respectively. The coefficient of repeatability (CR) of the SNR obtained from the two methods was also evaluated separately. RESULTS: Bland-Altman analysis comparing the single image set method and the reference showed 95% limits of agreement of -9.2 to 9.2% for the optimization group and -12.5 to 12.6% for the validation group. The SNR measurement had a CR of 21.1% using the reference method, and 13.8% using the single image set method. CONCLUSION: The single image method can be used for DTI SNR assessment and offers better repeatability. ADVANCES IN KNOWLEDGE: SNR of skeletal muscle DTI can be assessed for any data set without duplicate images.


Assuntos
Imagem de Tensor de Difusão/métodos , Músculo Esquelético/diagnóstico por imagem , Razão Sinal-Ruído , Adulto , Anisotropia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Reprodutibilidade dos Testes , Coxa da Perna/diagnóstico por imagem
12.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 44(5): 491-500, 2019 May 28.
Artigo em Chinês | MEDLINE | ID: mdl-31303611

RESUMO

OBJECTIVE: To explore the mechanism for changes in brain microstructure in long-term abstinent from methamphetamine-dependence by using the diffusion tensor imaging (DTI).
 Methods: A total of 26 patients with long-term abstinent methamphetamine-dependence, whose abstinence time more than 14 months, and 26 normal controls all underwent cognitive executive function tests and DTI scans. We used voxel-based analysis to compare the fractional anisotropy (FA) and mean diffusivity (MD) to obtain the abnormal brain regions of DTI parameters between the two groups. Spearman correlation analysis was used to explore the correlation between FA, MD of the brain regions with abnormal parameters and cognitive executive function tests.
 Results: There were no statistical differences in the cognitive executive function tests between the two groups (P>0.05). Compared with the normal control group, the long-term abstinent from methamphetamine-dependence group showed the decreased FA in the right precuneus, right superior frontal gyrus, right calcarine, left inferior temporal gyrus and the increased MD in the right triangular part of inferior frontal gyrus, right precuneus, right posterior cingulate, right middle temporal gyrus, bilateral middle occipital gyrus, left superior parietal lobule, and lobule VIII of cerebellar hemisphere. The MD values of the right middle temporal gyrus in the long-term abstinent group were negatively correlated with the number of completions within 60 seconds (r=-0.504) and within 120 seconds (r=-0.464) .
 Conclusion: The DTI parameters in multiple brain regions from the methamphetamine-dependence patients are still abnormal after a long-term abstinence. DTI can provide imaging evidence for brain microstructural abnormalities in long-term abstinent from methamphetamine-dependence.


Assuntos
Transtornos Relacionados ao Uso de Anfetaminas , Encéfalo , Anisotropia , Imagem de Tensor de Difusão , Humanos , Metanfetamina
13.
Eur J Radiol ; 116: 152-159, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31153558

RESUMO

BACKGROUND AND PURPOSE: Periventricular pseudocysts (PVPCs) are cystic cavities originating from the germinal matrix. The effects of PVPCs on the development of white matter (WM) in neonates remain unclear. This study aimed to characterise WM microstructural variations in neonates with PVPCs with and without additional abnormities on MRI. MATERIALS AND METHODS: Neonates with PVPCs and controls with no MRI abnormalities were retrospectively enrolled. Test subjects were divided into groups 1 (isolated PVPCs) and 2 (PVPCs with additional MRI abnormalities). The PVPC MRI features collected included lateralisation, locularity, anatomic location, and the maximum anteroposterior diameter. Diffusion tensor imaging (DTI)-derived fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD) were compared between the PVPC and control groups using tract-based spatial statistics. RESULTS: Thirty-eight neonates with PVPCs and 60 controls were enrolled. Groups 1 and 2 contained 15 and 23 subjects, respectively. The additional MRI findings in group 2 included intracranial haemorrhage, punctate WM lesions, hypoxic-ischaemic encephalopathy, and acute cerebral infarction. No significant differences were found in PVPC MRI features between the 2 test groups. Compared to controls, no significant changes in DTI metrics were observed in group 1 neonates; whereas extensive WM regions with decreased FA, increased RD, and unchanged/increased AD were found in group 2. CONCLUSIONS: Isolated PVPCs are not independently correlated with WM microstructural variations in neonates. This result provides further evidence for supporting the benign outcome of fetuses with isolated PVPCs.


Assuntos
Encefalopatias/patologia , Cistos/patologia , Substância Branca/patologia , Anisotropia , Encefalopatias/congênito , Estudos de Casos e Controles , Cistos/congênito , Imagem de Tensor de Difusão/métodos , Feminino , Humanos , Recém-Nascido , Masculino , Estudos Retrospectivos
14.
Eur J Radiol ; 116: 174-179, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31153561

RESUMO

PURPOSE: To evaluate any possible correlation between the presence of Isocitrate DeHydrogenase 1 mutation (IDH1m) and specific DTI (Diffusion Tensor Imaging) metrics, such as Fractional Anisotropy (FA), Mean Diffusivity (MD), Radial Diffusivity (RD) and Axial Diffusivity (AD). METHODS: We retrospectively analyzed 47 patients who underwent an advanced-MR study with DTI followed by surgical intervention with a subsequent histologic diagnosis of High-Grade Glioma (HGG) and immunohistochemical evaluation of IDH1 (Isocitrate DeHydrogenase) mutation status. For each DTI metrics we measured the ratio between tumor and normal tissue and we evaluated the correlation with IDH1 mutation. RESULTS: We observed a positive correlation with IDH1 status and RD and MD data. No correlation was demonstrated between IDH1 status and FA and AD. DISCUSSION: Our results support the hypothesis that the number of residual axonal fibers, extracellular matrix composition and the presence of colliquated tissue, may together contribute to a global RD increase in HGG, with a relatively higher increase in IDH1m tumors. CONCLUSIONS: Our data are in favor of a need for multimodal advance evaluation of HGG. DTI metrics help to analyze IDH1 mutation status, in order to better characterize the lesions and to tailor treatment and follow up.


Assuntos
Glioma/patologia , Isocitrato Desidrogenase/genética , Mutação/genética , Adulto , Idoso , Anisotropia , Imagem de Tensor de Difusão/métodos , Feminino , Glioma/genética , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Imagem Multimodal , Estudos Retrospectivos
15.
Eur J Radiol ; 116: 55-60, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31153574

RESUMO

OBJECTIVE: To determine the changes in fractional anisotropy (FA) at the proximal spinal cord and in magnetic resonance spectroscopy (MRS) of the precentral gyrus in patients with cervical spondylotic myelopathy (CSM) with respect to clinical symptoms and their duration. MATERIAL AND METHODS: 20 patients with CSM (7 female; mean age 64.6 ± 10.5 years) and 18 age/sex matched healthy controls (9 female; mean age 63.5 ± 6.6 years) were prospectively included. Clinical data (modified Japanese Orthopaedic Association Score (mJOA) and Neck Disability Index (NDI)) and 3T MR measurements including DTI at the spinal cord (level C2/3) with FA and MRS of the left and right precentral gyrus were taken. Clinical correlations and regression analyses were performed. RESULTS: Mean clinical scores of patients were significantly different to controls (mJOA; CSM: 10.2 ± 2.9; controls: 18.0 ± 0.0, p < 0.001; NDI; CSM: 41.4±23.5; controls: 4.4±6.6, p<0.001); FA was significantly lower in patients (CSM: 0.645 ± 0.067; controls: 0.699 ± 0.037, p = 0.005). MRS showed significantly lower metabolite concentrations between both groups: creatine (Cr) (CSM: 46.46±7.64; controls: 51.36±5.76, p = 0.03) and N-acetylaspartate (NAA) (CSM: 93.94±19.22; controls: 107.24±20.20, p = 0.05). Duration of symptoms ≤6 months was associated with increased myo-inositol (Ins) (61.58±17.76; 44.44±10.79; p = 0.02) and Ins/Cr ratio (1.36±0.47; 0.96±0.18; p = 0.014) compared to symptoms >6 months. CONCLUSION: Metabolic profiles of the precentral gyrus and FA in the uppermost spinal cord differ significantly between patients and healthy controls. Ins, thought to be a marker of endogenous neuroinflammatory response, is high in the early course of CSM and normalizes over time.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Córtex Motor/diagnóstico por imagem , Córtex Motor/metabolismo , Doenças da Medula Espinal/patologia , Espondilose/patologia , Idoso , Anisotropia , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Biomarcadores/metabolismo , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/patologia , Creatina/metabolismo , Feminino , Humanos , Inositol/metabolismo , Masculino , Pessoa de Meia-Idade , Córtex Motor/patologia , Doenças da Medula Espinal/metabolismo , Espondilose/metabolismo , Fatores de Tempo
16.
Chemosphere ; 233: 667-676, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31195271

RESUMO

In situ delivery of liquid reagents in vadose zone is limited by soil anisotropy and gravity. The enhanced delivery of persulfate (PS) as oxidant, using a new foam-based method (F-PS) was compared at bench-scale to traditional water-based (W-PS) and surfactant solution-based (S-PS) deliveries. The goal was to distribute PS uniformly in coal tar-contaminated unsaturated and anisotropic soils, both in terms of permeability and contamination. Water was the less efficiently delivered fluid because of the hydrophobicity of the contaminated soils. Surfactant enhanced PS-distribution into contaminated zones by reducing interfacial tension and inverting soil wettability. Regardless of coal tar contamination contrasts (0 vs. 5 and 1 vs. 10 g kg soil-1) or strong permeability contrasts, PS-solution injection after foam injection led to the most uniform reagents delivery. While PS-concentration varied more than 5-times between zones using W-PS and S-PS methods, it varied less than 1.6-times when the F-PS one was used. Finally, despite unfavorable conditions, the foam-based method did not show any detrimental effect regarding the oxidation of hydrocarbons compared to the W-PS and S-PS methods carried out in ideal conditions. Moreover, hydrocarbon degradation rates were slightly higher when using F-PS than S-PS due to a lower surfactant content in the targeted zone.


Assuntos
Recuperação e Remediação Ambiental/métodos , Hidrocarbonetos/análise , Poluentes do Solo/análise , Anisotropia , Alcatrão , Poluição Ambiental , Oxidantes , Oxirredução , Estresse Oxidativo , Permeabilidade , Solo/química , Tensoativos , Água
17.
Radiol Med ; 124(10): 946-954, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31197647

RESUMO

PURPOSE: To evaluate the role of DTI (with fibretracking) and T2-weighted imaging (T2-WI) used together for predicting extra-capsular extension in patients with localized prostate cancer. METHOD AND MATERIALS: Thirty-six patients with biopsy-proven diagnosis of prostatic neoplasia performed MRI and underwent radical prostatectomy. Histopathological analysis showed ECE in 15/36 and capsule sparing in 21/36. By means of T2-WI, ECE was evaluated in a qualitative manner, according to PI-RADS v.2 (two groups with low and high risk of ECE); sensitivity and specificity were calculated for both groups. We performed a quantitative analysis on two tractographic parameters, fractional anisotropy (FA) and apparent diffusion coefficient (ADC) and computed the ratio between the lesion quadrant and its contralateral (L/H ratio). We compared L/H ratios of patients with and without ECE; ROC analyses were performed to determinate ECE cut-off values of tractographic parameters. These cut-off values were used in association with T2-WI to reassess patients and to evaluate whether specificity and sensitivity of ECE detection change. RESULTS: T2-WI showed a sensitivity of 80% and a specificity of 71% in detection of ECE. Tractography displayed a significant difference in L/H ratio for FA and ADC between patients with and without ECE. The simultaneous use of T2-WI and tractography revealed high sensitivity (100%) on patients with low suspect of ECE (on T2-WI) and high specificity (83%) on patients with high suspect of ECE (on T2-WI). CONCLUSION: The morphologic component of T2-weighted imaging and functional aspect of DTI should be interpreted together to more successfully assess the presence of ECE.


Assuntos
Imagem por Ressonância Magnética/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia , Adulto , Idoso , Anisotropia , Biópsia , Meios de Contraste , Imagem de Difusão por Ressonância Magnética , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/diagnóstico por imagem , Invasividade Neoplásica/patologia , Compostos Organometálicos , Estudos Prospectivos , Prostatectomia , Neoplasias da Próstata/cirurgia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Invest Ophthalmol Vis Sci ; 60(6): 1906-1913, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31042798

RESUMO

Purpose: We investigated the pattern of meridional anisotropies, if any, for pattern onset-offset visual evoked potential (POVEPs) responses and psychophysical grating acuity (GA) in children with normal letter visual acuity (20/20 or better). Methods: A total of 29 children (aged 3-9 years), nine of whom were astigmatic (AS), were recruited. Orientation-specific monocular POVEPs were recorded in response to sinewave grating stimuli oriented along the subjects' principal AS meridians. Horizontal and vertical gratings were designated Meridians 1 and 2, respectively, for nonastigmatic patients (Non-AS). Binocular POVEPs in response to the same stimuli, but oriented at 45°, 90°, 135°, and 180°, were recorded. Psychophysical GAs were assessed monocularly and binocularly along the same meridians using the same stimuli by a 2-alternative-forced-choice staircase technique. The C3 amplitudes and peak latencies of the POVEP and GAs were compared across meridians using linear mixed models (monocular) and ANOVA (binocular). Results: There were significant meridional anisotropies in monocular C3 amplitudes regardless of astigmatism status (P = 0.001): Meridian 2 (mean ± SE Non-AS, 30.13 ± 2.07 µV; AS, 26.53 ± 2.98 µV) was significantly higher than Meridian 1 (Non-AS, 26.14 ± 1.87 µV; AS, 21.68 ± 2.73 µV; P = 0.019), but no meridional anisotropies were found for GA or C3 latency. Binocular C3 amplitude in response to horizontally oriented stimuli (180°, 29.71 ± 3.06 µV) was significantly lower than the oblique (45°, 36.62 ± 3 .05 µV; P = 0.03 and 135°, 35.95 ± 2.92 µV; P = 0.04) and vertical (90°, 37.82 ± 3.65 µV; P = 0.02) meridians, and binocular C3 latency was significantly shorter in response to vertical than oblique gratings (P ≤ 0.001). Conclusions: Meridional anisotropy was observed in children with normal vision. The findings suggest that horizontal gratings result in a small, but significantly lower POVEP amplitude than for vertical and oblique gratings.


Assuntos
Astigmatismo/fisiopatologia , Potenciais Evocados Visuais/fisiologia , Orientação/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Psicofísica/métodos , Visão Binocular/fisiologia , Acuidade Visual , Anisotropia , Astigmatismo/diagnóstico , Criança , Pré-Escolar , Feminino , Humanos , Masculino
20.
Nanomedicine (Lond) ; 14(9): 1203-1226, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31075049

RESUMO

Gold nanoparticles have drawn attention to nanomedicine for many years due to their physicochemical properties, which include: good stability; biocompatibility; easy surface chemistry and superior magnetic; and last, electronic properties. All of these properties distinguish gold nanoparticles as advantageous carriers to be exploited. The challenge to develop new gold nanostructures has led to anisotropy, a new property to exploit for various medical applications: diagnostic and imaging strategies as well as therapeutic options. Gold nanorods are the most studied anisotropic gold nanoparticles because of the presence of two absorption peaks according to their longitudinal and transversal plasmon resonances. The longitudinal surface plasmonic resonance can provide the absorption in the near-infrared region and this is an important aspect of using gold nanorods for medical purposes.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Nanotubos/química , Anisotropia , Materiais Biocompatíveis/química , Corantes/química , Portadores de Fármacos/química , Hipertermia Induzida , Fototerapia , Dióxido de Silício/química
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