Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 179
Filter
1.
Neuroscience Bulletin ; (6): 181-199, 2022.
Article in English | WPRIM | ID: wpr-922672

ABSTRACT

The glymphatic system plays a pivotal role in maintaining cerebral homeostasis. Chronic cerebral hypoperfusion, arising from small vessel disease or carotid stenosis, results in cerebrometabolic disturbances ultimately manifesting in white matter injury and cognitive dysfunction. However, whether the glymphatic system serves as a potential therapeutic target for white matter injury and cognitive decline during hypoperfusion remains unknown. Here, we established a mouse model of chronic cerebral hypoperfusion via bilateral common carotid artery stenosis. We found that the hypoperfusion model was associated with significant white matter injury and initial cognitive impairment in conjunction with impaired glymphatic system function. The glymphatic dysfunction was associated with altered cerebral perfusion and loss of aquaporin 4 polarization. Treatment of digoxin rescued changes in glymphatic transport, white matter structure, and cognitive function. Suppression of glymphatic functions by treatment with the AQP4 inhibitor TGN-020 abolished this protective effect of digoxin from hypoperfusion injury. Our research yields new insight into the relationship between hemodynamics, glymphatic transport, white matter injury, and cognitive changes after chronic cerebral hypoperfusion.


Subject(s)
Animals , Brain Ischemia , Carotid Stenosis/drug therapy , Cognitive Dysfunction/etiology , Digoxin , Disease Models, Animal , Mice , Mice, Inbred C57BL , White Matter
2.
Rev. bras. neurol ; 57(3): 32-36, jul.-set. 2021.
Article in English | LILACS | ID: biblio-1342529

ABSTRACT

The extensive white matter of the brain, which comprises about one half of its volume, is constituted by an intricate and interwoven assemble of nerve fibers. The WMH (leukoaraiosis) represent the most frequent ischemic type of lesion of SVD, affecting the white matter. These lesions may be apparent or normal appearing on neuroimaging. In both cases such lesions may interrupt the affected white matter fibers, with consequent disconnection syndromes, and atrophy of the denervated grey matter structures. These conditions affect the structural neural networks (connectome), with functional repercussion on the cognitive and behavioral domains.


A extensa substância branca do cérebro, que compreende cerca da metade do seu volume, é constituída por um intricado e entrelaçado conjunto de fibras nervosas. As HSB (hiperintensidades da substância branca) (leucoaraiose) representam o mais frequente tipo de lesão isquêmica da DPV (doença dos pequenos vasos) que afeta a substância branca. Essas lesões podem ser aparentes ou de aparência normal na neuroimagem. Em ambos os casos tais lesões podem interromper essas fibras da substância branca, com consequente síndromes por desconexão e atrofia de estruturas de substância cinzenta desnervadas. Essas condições afetam as redes neurais estruturais (conectoma), com repercussão funcional nos domínios cognitivo e do comportamento.


Subject(s)
Humans , Aged , Aged, 80 and over , White Matter/physiopathology , White Matter/diagnostic imaging , Magnetic Resonance Imaging/methods , Denervation , Leukoaraiosis/pathology
3.
Rev. bras. neurol ; 57(2): 14-17, abr.-jun. 2021. tab, ilus
Article in English | LILACS | ID: biblio-1280778

ABSTRACT

The white matter hyperintensities (WMH, leucoaraiosis) represent the most common kind of ischemic vascular lesion of the white matter due to small vessel diseases, and occurs frequently in the elderly. Consequent to the neuroimaging identification arouse the need for their assessment. The group of Fazekas proposed a systematized semi-quantitative visual scale to score such lesions where two parameters were considered, extent and localization. The original scale was further modified, to a simplified version. Although other more complex scales have appeared, researchers remarked that the relatively simple Fazekas scale, in comparison to the complex ones and to volumetric measures, appeared to be sufficient when analyzing relationships between clinical parameters and WMH load in a clinical setting.


As hiperintensidades da substância branca (HSB, leucoaraiose) representam o tipo de lesão isquêmica mais comum da substância branca decorrente de doenças de pequenos vasos e ocorre frequentemente em idosos. Consequente à identificação por neuroimagem surgiu a necessidade de sua avaliação. O grupo de Fazekas propos uma escala visual semiquantitativa sistematizada para pontuar tais lesões, onde foram considerados dois parâmetros, extensão e localização. A escala original foi modificada para constituir uma versão mais simplificada. Embora outras escalas mais complexas tenham aparecido, pesquisadores comentaram que a relativamente simples escala de Fazekas, em comparação às mais complexas e a método volumétrico, mostrou-se suficiente quando é analisada a relação entre parâmetros clínicos e a carga de HSB em um cenário clínico.


Subject(s)
Humans , Aged , Aged, 80 and over , Leukoaraiosis/pathology , Leukoaraiosis/diagnostic imaging , White Matter/diagnostic imaging , Aging , Brain Ischemia/diagnostic imaging , Neuroimaging/methods
4.
Article in Chinese | WPRIM | ID: wpr-879868

ABSTRACT

OBJECTIVE@#To study the effect of human oligodendrocyte precursor cell (hOPC) transplantation in the treatment of white matter injury (WMI).@*METHODS@#Neonatal rats were randomly divided into a sham-operation group, a model group, and a transplantation group (@*RESULTS@#The place navigation test using the Morris water maze showed that the model group had a significantly longer escape latency than the sham-operation group, and compared with the model group, the transplantation group had a significant reduction in escape latency (@*CONCLUSIONS@#Intrathecal hOPC transplantation may alleviate neurological injury and promote remyelination in a rat model of WMI.


Subject(s)
Animals , Animals, Newborn , Humans , Myelin Sheath , Oligodendrocyte Precursor Cells , Oligodendroglia , Rats , White Matter
5.
Article in Chinese | WPRIM | ID: wpr-879850

ABSTRACT

OBJECTIVE@#To study the effect of different melatonin treatment regimens on long-term behavior and white matter damage in neonatal rats with hypoxic-ischemic brain damage (HIBD), and to seek an optimal melatonin treatment regimen.@*METHODS@#Healthy Sprague-Dawley rats, aged 7 days, were randomly divided into four groups: sham-operation, HIBD, single-dose immediate treatment (SDIT), and 7-day continuous treatment (7DCT), with 8 rats in each group. A neonatal rat model of HIBD was prepared according to the classical Rice-Vannucci method. On day 21 after HIBD, the Morris water maze test was used to evaluate spatial learning and memory abilities. On day 70 after HIBD, immunofluorescence assay was used to measure the expression of neuronal nuclear antigen (NeuN) in the cerebral cortex and the hippocampal CA1 region of neonatal rats, and double-label immunofluorescence was used to measure the expression of myelin basic protein (MBP) and neurofilament 200 (NF200) in the corpus striatum and the corpus callosum.@*RESULTS@#The results of the Morris water maze test showed that the SDIT and 7DCT groups had a significantly shorter mean escape latency than the HIBD group, and the 7DCT group had a significantly shorter mean escape latency than the SDIT group (@*CONCLUSIONS@#Both SDIT and 7DCT can improve long-term behavior and reduce white matter damage in neonatal rats with HIBD, and 7DCT is more effective than SDIT.


Subject(s)
Animals , Animals, Newborn , Hypoxia-Ischemia, Brain/drug therapy , Melatonin/pharmacology , Rats , Rats, Sprague-Dawley , White Matter
6.
Article in Chinese | WPRIM | ID: wpr-879282

ABSTRACT

Diffusion tensor imaging technology can provide information on the white matter of the brain, which can be used to explore changes in brain tissue structure, but it lacks the specific description of the microstructure information of brain tissue. The neurite orientation dispersion and density imaging make up for its shortcomings. But in order to accurately estimate the brain microstructure, a large number of diffusion gradients are needed, and the calculation is complex and time-consuming through maximum likelihood fitting. Therefore, this paper proposes a kind of microstructure parameters estimation method based on the proximal gradient network, which further avoids the classic fitting paradigm. The method can accurately estimate the parameters while reducing the number of diffusion gradients, and achieve the purpose of imaging quality better than the neurite orientation dispersion and density imaging model and accelerated microstructure imaging via convex optimization model.


Subject(s)
Brain/diagnostic imaging , Diffusion Magnetic Resonance Imaging , Diffusion Tensor Imaging , Neurites , White Matter
7.
Frontiers of Medicine ; (4): 125-138, 2021.
Article in English | WPRIM | ID: wpr-880937

ABSTRACT

This study aimed to define the most consistent white matter microarchitecture pattern in Parkinson's disease (PD) reflected by fractional anisotropy (FA), addressing clinical profiles and methodology-related heterogeneity. Web-based publication databases were searched to conduct a meta-analysis of whole-brain diffusion tensor imaging studies comparing PD with healthy controls (HC) using the anisotropic effect size-signed differential mapping. A total of 808 patients with PD and 760 HC coming from 27 databases were finally included. Subgroup analyses were conducted considering heterogeneity with respect to medication status, disease stage, analysis methods, and the number of diffusion directions in acquisition. Compared with HC, patients with PD had decreased FA in the left middle cerebellar peduncle, corpus callosum (CC), left inferior fronto-occipital fasciculus, and right inferior longitudinal fasciculus. Most of the main results remained unchanged in subgroup meta-analyses of medicated patients, early stage patients, voxel-based analysis, and acquisition with 30 diffusion directions. The subgroup meta-analysis of medication-free patients showed FA decrease in the right olfactory cortex. The cerebellum and CC, associated with typical motor impairment, showed the most consistent FA decreases in PD. Medication status, analysis approaches, and the number of diffusion directions have an important impact on the findings, needing careful evaluation in future meta-analyses.


Subject(s)
Anisotropy , Brain/diagnostic imaging , Corpus Callosum , Diffusion Tensor Imaging , Humans , Parkinson Disease/diagnostic imaging , White Matter/diagnostic imaging
8.
Acta Physiologica Sinica ; (6): 407-422, 2021.
Article in Chinese | WPRIM | ID: wpr-887677

ABSTRACT

As the two essential components, the white matter and gray matter compose the central nervous system of the brain. Widely known that axons of neurons mainly form the white matter, and these formed nerve fibers are responsible for transmitting information among various brain regions to achieve the coordinated operation of the entire brain. Early research on the white matter could only be done by dissecting living animals or human cadavers, until Basser et al. proposed diffusion tensor imaging (DTI) technology in 1994, which could detect the diffusion characteristics of water in the brain in vivo noninvasively. Accordingly, this technology could be applied to investigate the diffusion movement of water in white matter to obtain the information of direction and micro-anatomy of white matter fiber bundles. With the advancement on the display and analysis of the anatomical structure of white matter fiber bundles, the exploration of microscopic pathological changes, and the assistance of clinical diagnosis and neurophysiological research, DTI technology has become one of the most popular topics in brain science research. Chronic pain refers to pain lasting more than three months, which not only seriously affects the patient's physical and social functions, but also dramatically reduces the quality of life. It was reported that long-term pain stimulation might cause pathological remodeling of the central nervous system, and abnormalities in white matter were found in imaging examinations of patients with chronic pain. This review introduces the quantitative analysis methods of white matter fiber bundle microstructure based on DTI and its application in chronic pain, and further discusses the application value of DTI technology on clinical research of chronic pain.


Subject(s)
Animals , Brain , Chronic Pain/diagnostic imaging , Diffusion Tensor Imaging , Humans , Quality of Life , White Matter/diagnostic imaging
9.
Article in English | WPRIM | ID: wpr-922587

ABSTRACT

OBJECTIVES@#White matter hyperintensity (WMH) is an important factor leading to cognitive impairment, and the mechanism has not been clarified. In recent years, studies have found that circular RNA (circRNA) has differential expression in cerebrovascular diseases. This study aims to analyze the expression profile of circRNA in peripheral blood mononuclear cell (PBMC) of patients with WMH with cognitive impairment, to screen the differentially expressed circRNA, and to explore the possible role of circRNA in WMH with cognitive impairment.@*METHODS@#CircRNA microarray was used to detect the circRNA expression profile of PBMC in patients with WMH with cognitive impairment, and in patients with WMH without cognitive impairment as well as in normal controls (3 cases each, male to female ratio of 2꞉1). The differentially expressed circRNA in patients with WMH with cognitive impairment was screened. The screening criteria for differentially expressed circRNA was fold change (FC) ≥2.0 (|log@*RESULTS@#Compared with the control group, there were 5 significantly up-regulated circRNA and 3 down-regulated circRNA in the WMH with cognitive impairment group; 8 circRNA were significantly up-regulated and 2 were down-regulated in the WMH without cognitive impairment group. When compared with the WMH with cognitive impairment group, no co-differentially expressed circRNA was found in WMH without cognitive impairment group and control group. Compared with the control group, the expression of hsa_circ_0092222 was up-regulated and the expressions of hsa_circ_0000662 and hsa_circ_0083773 were down-regulated in the WMH with cognitive impairment group and the WMH without cognitive impairment group, and there was no significant difference between the 2 groups (all @*CONCLUSIONS@#The circRNA expression profile of patients with WMH is changed significantly. The differentially expressed circRNA may be the cause of WMH; Hsa_circ_0092222, hsa_circ_0000662, and hsa_circ_0083773 may regulate the expression of target genes by targeting adsorption of the target miRNA, leading to brain white matter damage through Janus kinase 2 (JAK2)/signal transducers and activators of transcription (STAT3) signal pathway and Wnt signal pathway.There is no significant difference in circRNA expression profile between WMH with or without cognitive impairment. Cognitive impairment in patients with WMH may have other reasons.


Subject(s)
Cognitive Dysfunction/genetics , Female , Humans , Leukocytes, Mononuclear , Male , MicroRNAs , RNA/genetics , RNA, Circular , Software , White Matter
10.
Frontiers of Medicine ; (4): 887-902, 2021.
Article in English | WPRIM | ID: wpr-922517

ABSTRACT

Monocarboxylic acid transporter 1 (MCT1) maintains axonal function by transferring lactic acid from oligodendrocytes to axons. Subarachnoid hemorrhage (SAH) induces white matter injury, but the involvement of MCT1 is unclear. In this study, the SAH model of adult male Sprague-Dawley rats was used to explore the role of MCT1 in white matter injury after SAH. At 48 h after SAH, oligodendrocyte MCT1 was significantly reduced, and the exogenous overexpression of MCT1 significantly improved white matter integrity and long-term cognitive function. Motor training after SAH significantly increased the number of ITPR2


Subject(s)
Animals , Male , MicroRNAs/genetics , Monocarboxylic Acid Transporters/genetics , Rats , Rats, Sprague-Dawley , Subarachnoid Hemorrhage , Symporters/genetics , White Matter/injuries
12.
Article in Chinese | WPRIM | ID: wpr-828679

ABSTRACT

OBJECTIVE@#To study the value of fractional anisotropy (FA) of regions of interest (ROI) on magnetic resonance diffusion tensor imaging (DTI) in bilirubin-induced neurological dysfunction in neonates.@*METHODS@#A total of 91 neonates with hyperbilirubinemia who were hospitalized from January 2017 to January 2018 were enrolled. According to the peak level of total serum bilirubin, they were divided into three groups: mild/moderate increase (n=45), severe increase (n=35), and extremely severe increase (n=11). According to the presence or absence of abnormal neurological manifestations, they were divided into two groups: neurological dysfunction (n=20) and non-neurological dysfunction (n=71). Ten healthy full-term infants were enrolled as the control group. Head DTI was performed for all neonates to measure the FA values of the bilateral globus pallidus, the anterior limb of the internal capsule, the posterior limb of the internal capsule, and the cerebellar dentate nucleus.@*RESULTS@#The extremely severe increase group had significantly lower FA values of the globus pallidus than the control, mild/moderate increase, and severe increase groups (P<0.05). The severe increase group had significantly lower FA values of the globus pallidus than the control group (P<0.05). The extremely severe increase group had significantly lower FA values of the posterior limb of the internal capsule than the control, mild/moderate increase, and severe increase groups (P<0.05). The neurological dysfunction group had significantly lower FA values of the globus pallidus and the posterior limb of the internal capsule than the non-neurological dysfunction group (P<0.05).@*CONCLUSIONS@#Serum bilirubin level combined with the changes in the DTI FA values of the globus pallidus and the posterior limb of the internal capsule can be used to predict the injury of cerebral nuclei and white matter fibers.


Subject(s)
Anisotropy , Bilirubin , Brain , Diffusion Magnetic Resonance Imaging , Diffusion Tensor Imaging , Humans , Infant, Newborn , Magnetic Resonance Imaging , Magnetic Resonance Spectroscopy , White Matter
13.
Clinics ; 75: e2245, 2020. tab
Article in English | LILACS | ID: biblio-1142775

ABSTRACT

OBJECTIVES: Although a large number of studies have shown brain volumetric differences between men and women, only a few investigations have analyzed brain tissue volumes in representative samples of the general elderly population. We investigated differences in gray matter (GM) volumes, white matter (WM) volumes, and intracranial volumes (ICVs) between the sexes in individuals older than 66 years using structural magnetic resonance imaging (MRI). METHODS: Using FreeSurfer version 5.3, we obtained the ICVs and GM and WM volumes from the MRI datasets of 84 men and 92 women. To correct for interindividual variations in ICV, GM and WM volumes were adjusted with a method using the residuals of a least-square-derived linear regression between raw volumes and ICVs. We then performed an analysis of covariance comparing men and women, including age and years of schooling as confounding factors. RESULTS: Women had a lower socioeconomic status overall and fewer years of schooling than men. The comparison of unadjusted brain volumes showed larger GM and WM volumes in men. After the ICV correction, the adjusted volumes of GM and WM were larger in women. CONCLUSION: After the ICV correction and taking into account differences in socioeconomic status and years of schooling, our results confirm previous findings of proportionally larger GM in women, as well as larger WM volumes. These results in an elderly population indicate that brain volumetric differences between sexes persist throughout the aging process. Additional studies combining MRI and other biomarkers to identify the hormonal and molecular bases influencing such differences are warranted.


Subject(s)
Humans , Male , Female , Aged , Brain/diagnostic imaging , White Matter , Magnetic Resonance Imaging , Linear Models , Gray Matter/diagnostic imaging
14.
Medicina (B.Aires) ; 79(supl.3): 10-14, set. 2019. ilus
Article in Spanish | LILACS | ID: biblio-1040542

ABSTRACT

Los nacimientos prematuros son uno de los principales indicadores de salud de un país. Están asociados a una alta mortalidad e importante morbilidad en niños con parálisis cerebral y otros trastornos del neurodesarrollo, incluyendo problemas cognitivos y del aprendizaje. Los principales tipos de lesión encefálica en los recién nacidos prematuros son: a) las lesiones de la sustancia blanca, generalmente asociadas a alteraciones neuronales y axonales en la corteza cerebral y otras zonas de sustancia gris; b) hemorragias intracraneanas que incluyen las de la matriz germinal, intraventriculares e intraparenquimatosas y c) del cerebelo. Las lesiones de sustancia blanca incluyen la leucomalacia periventricular quística, no quística (con focos de necrosis microscópicos) y lesiones difusas de sustancia blanca, no necróticas. Estas lesiones tienen múltiples factores etiológicos. Las características anatómicas y fisiológicas de las estructuras vasculares periventriculares predisponen a la sustancia blanca a ser muy vulnerable a las situaciones de isquemia cerebral y, en interacción con factores infecciosos/inflamatorios, activan a las microglías generando estrés oxidativo (por liberación de radicales libres del oxígeno y del nitrógeno), liberación de citoquinas proinflamatorias, liberación de glutamato, fallo energético y alteración de la integridad vascular. Todo lo anteriormente mencionado genera una particular vulnerabilidad de los pre-oligodendrocitos que termina alterando la mielinización. La hipoxia-isquemia también puede producir necrosis neuronal selectiva en diferentes regiones encefálicas. La matriz germinal es un área altamente vascularizada en la región subependimaria periventricular con una estructura capilar muy frágil que la predispone a las hemorragias.


Preterm birth is one of the main country health indicators. It is associated with high mortality and significant morbidity in preterm newborns with cerebral palsy and potential long-term neurodevelopmental disabilities like cognitive and learning problems. The main lesions could be: a) white matter injuries, generally associated with cortical and other regions of grey matter neuronal-axonal disturbances; b) intracranial hemorrhage that includes germinal matrix, intraventricular and parenchymal, c) cerebellum injuries. The white matter lesions include cystic and non-cystic (with microscopic focal necrosis) periventricular leukomalacia and non-necrotic diffuse white matter injury. Multiple etiologic factors are associated with these injuries. Anatomical and physiological characteristics of periventricular vascular structures predispose white matter to cerebral ischemia and, interacting with infection/inflammation factors, activate microglia, generating oxidative stress (mediated by free oxygen and nitrogen radicals), pro-inflammatory cytokine and glutamate toxicity, energetic failure and vascular integrity disturbances. All these factors lead to a particular vulnerability of pre-oligodendrocytes that will affect myelination. Hypoxia-ischemia also may produce selective neuronal necrosis in different cerebral regions. Germinal matrix is a highly vascularized zone beneath ependymal or periventricular region that constitutes a capillary bed with a particular structural fragility that predispose it to hemorrhage.


Subject(s)
Humans , Infant, Newborn , Leukomalacia, Periventricular/etiology , Brain Injuries/etiology , Infant, Premature , Brain Ischemia/etiology , Cerebral Palsy/etiology , Hypoxia-Ischemia, Brain/etiology , Brain Injuries/mortality , Brain Injuries/diagnostic imaging , Brain Ischemia/mortality , Brain Ischemia/diagnostic imaging , Cerebral Palsy/mortality , Hypoxia-Ischemia, Brain/mortality , Hypoxia-Ischemia, Brain/diagnostic imaging , White Matter/pathology
15.
Rev. argent. radiol ; 83(3): 95-101, set. 2019. ilus, tab
Article in Spanish | LILACS | ID: biblio-1057407

ABSTRACT

Objetivo Desde la aparición de la tractografía, al tratarse de una técnica no invasiva y que usa la ampliamente conocida resonancia magnética (RM), el estudio de la sustancia blanca se ha facilitado. A partir de eso, se han logrado grandes descubrimientos en cuanto a fascículos cerebrales involucrados en funciones cognitivas. Sin embargo, su evaluación sigue siendo subjetiva y depende de la experiencia y entrenamiento del evaluador, razón por la cual se ha limitado su aplicabilidad en la práctica clínica. En ese sentido, es conveniente parametrizar volúmenes cerebrales de sustancia blanca en población sana a través de una herramienta electrónica que se pueda reproducir y así poderlo aplicar en enfermos. Materiales y métodos Se reportan 10 sujetos sanos desde el punto de vista neurológico. Para cada sujeto, se adquirieron imágenes ponderadas por difusión y los resultados se visualizaron mediante FiberNavigator (http://scilus.github.io/fibernavigator). Finalmente, esa misma herramienta fue utilizada para purificar los fascículos objeto de estudio y realizar el conteo de las fibras. Resultados Se obtuvieron valores de volumetría del fascículo longitudinal superior (FLS), fascículo longitudinal inferior (FLI), fascículo frontoccipital inferior (FFI), fascículo uncinado (FU) y fascículo del cíngulo (FC), identificando que no existen diferencias estadísticamente significativas entre el número de fibras que componen los fascículos cerebrales. Discusión Los resultados alcanzados de la anatomía y la direccionalidad de fibras de los fascículos cerebrales de este estudio coinciden con el resto de la evidencia publicada hasta el momento, sin encontrar diferencias en cuanto a su organización y recorrido. Conclusión Aunque esos resultados no sirven como valores de referencia para ser aplicados en pacientes con patología neurológica, brindamos información inexistente hasta el momento, con ese equipo en específico y la reproducción entre los distintos usuarios y el software.


Objective Since the appearance of tractography, as it is a non-invasive technique and uses the widely known magnetic resonance (MR), the study of white matter has been facilitated. After this, great discoveries have been made regarding the brain fascicles involved in cognitive functions. However, its evaluation continues to be subjective and depends on the evaluator's experience and training. That the reason why its applicability has been limited in clinical practice. Because of this, it is convenient to parametrize cerebral volumes of white matter in healthy population through an electronic, reproducible tool that could be applied in patients. Materials and Methods Ten neurologically healthy subjects are reported, for each subject we acquired images weighted by diffusion and the results were visualized by means of FiberNavigator (http://scilus.github.io/fibernavigator). Finally, this same tool was used to purify the fascicles under study and perform the fiber count. Results Volumetric values of the upper longitudinal fasciculus, inferior longitudinal fasciculus, inferior frontoccipital fasciculus, uncinated fasciculus and cingulate fasciculus were obtained, identifying that there are not statistically significant differences in the number of fibers that make up the cerebral fascicles. Discussion The results achieved of the anatomical and fiber directionality of the cerebral fascicles of this study, coincide with the rest of the evidence published up to now, without finding differences regarding its organization and route. Conclusion Although these results do not serve as reference values to be applied in patients with neurological pathology, do we provide nonexistent information so far, with this specific equipment and the reproducibility between the different users and the software.


Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Young Adult , Cognition/physiology , White Matter/diagnostic imaging , Reference Values , Anisotropy , Titrimetry/standards , Diffusion Tensor Imaging/standards , Nerve Fibers
17.
Rev. bras. psiquiatr ; 41(2): 101-111, Mar.-Apr. 2019. tab, graf
Article in English | LILACS | ID: biblio-990827

ABSTRACT

Objective: To compare results of positron emission tomography (PET) with carbon-11-labeled Pittsburgh compound B (11C-PIB) obtained with cerebellar or global brain uptake for voxel intensity normalization, describe the cortical sites with highest tracer uptake in subjects with mild Alzheimer's disease (AD), and explore possible group differences in 11C-PIB binding to white matter. Methods: 11C-PIB PET scans were acquired from subjects with AD (n=17) and healthy elderly controls (n=19). Voxel-based analysis was performed with statistical parametric mapping (SPM). Results: Cerebellar normalization showed higher 11C-PIB uptake in the AD group relative to controls throughout the cerebral cortex, involving the lateral temporal, orbitofrontal, and superior parietal cortices. With global uptake normalization, greatest cortical binding was detected in the orbitofrontal cortex; decreased 11C-PIB uptake in white matter was found in the posterior hippocampal region, corpus callosum, pons, and internal capsule. Conclusion: The present case-control voxelwise 11C-PIB PET comparison highlighted the regional distribution of amyloid deposition in the cerebral cortex of mildly demented AD patients. Tracer uptake was highest in the orbitofrontal cortex. Decreased 11C-PIB uptake in white-matter regions in this patient population may be a marker of white-matter damage in AD.


Subject(s)
Humans , Male , Female , Aged , Aged, 80 and over , Carbon Radioisotopes , Cerebral Cortex/diagnostic imaging , Positron-Emission Tomography/methods , Alzheimer Disease/diagnostic imaging , White Matter/diagnostic imaging , Severity of Illness Index , Case-Control Studies
18.
Article in Korean | WPRIM | ID: wpr-764671

ABSTRACT

PURPOSE: The purpose of this study was to identify the effect of ghrelin on memory impairment in a rat model of vascular dementia induced by chronic cerebral hypoperfusion. METHODS: Randomized controlled groups and the posttest design were used. We established the representative animal model of vascular dementia caused by bilateral common carotid artery occlusion and administered 80 µg/kg ghrelin intraperitoneally for 4 weeks. First, behavioral studies were performed to evaluate spatial memory. Second, we used molecular biology techniques to determine whether ghrelin ameliorates the damage to the structure and function of the white matter and hippocampus, which are crucial to learning and memory. RESULTS: Ghrelin improved the spatial memory impairment in the Y-maze and Morris water maze test. In the white matter, demyelination and atrophy of the corpus callosum were significantly decreased in the ghrelin-treated group. In the hippocampus, ghrelin increased the length of hippocampal microvessels and reduced the microvessels pathology. Further, we confirmed angiogenesis enhancement through the fact that ghrelin treatment increased vascular endothelial growth factor (VEGF)-related protein levels, which are the most powerful mediators of angiogenesis in the hippocampus. CONCLUSION: We found that ghrelin affected the damaged myelin sheaths and microvessels by increasing angiogenesis, which then led to neuroprotection and improved memory function. We suggest that further studies continue to accumulate evidence of the effect of ghrelin. Further, we believe that the development of therapeutic interventions that increase ghrelin may contribute to memory improvement in patients with vascular dementia.


Subject(s)
Animals , Atrophy , Carotid Artery, Common , Corpus Callosum , Dementia , Dementia, Vascular , Demyelinating Diseases , Ghrelin , Hippocampus , Humans , Learning , Memory Disorders , Memory , Microvessels , Models, Animal , Molecular Biology , Myelin Sheath , Neuroprotection , Pathology , Rats , Spatial Memory , Vascular Endothelial Growth Factor A , Water , White Matter
19.
Experimental Neurobiology ; : 300-310, 2019.
Article in English | WPRIM | ID: wpr-739536

ABSTRACT

Over the years, diffusion tractography has seen increasing use for comparing minute differences in connectivity of brain structures in neurodegenerative diseases and treatments. Studies on connectivity between basal ganglia has been a focal point for studying the effects of diseases such as Parkinson's and Alzheimer's, as well as the effects of treatments such as deep brain stimulation. Additionally, in previous studies, diffusion tractography was utilized in disease mouse models to identify white matter alterations, as well as biomarkers that occur in the progression of disease. However, despite the extensive use of mouse models to study model diseases, the structural connectivity of the mouse basal ganglia has been inadequately explored. In this study, we present the methodology of segmenting the basal ganglia of a mouse brain, then generating diffusion tractography between the segmented basal ganglia structures. Additionally, we compare the relative levels of connectivity of connecting fibers between each basal ganglia structure, as well as visualize the shapes of each connection. We believe that our results and future studies utilizing diffusion tractography will be beneficial for properly assessing some of the connectivity changes that are found in the basal ganglia of various mouse models.


Subject(s)
Animals , Basal Ganglia , Biomarkers , Brain , Deep Brain Stimulation , Diffusion Tensor Imaging , Diffusion , Magnetic Resonance Imaging , Mice , Neurodegenerative Diseases , White Matter
20.
Experimental Neurobiology ; : 119-129, 2019.
Article in English | WPRIM | ID: wpr-739526

ABSTRACT

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a progressive degenerative white matter disorder caused by mutations in the tyrosine kinase domain of the CSF1R gene. ALSP is often misdiagnosed as other diseases due to its rarity and various clinical presentations such as Parkinsonism, pyramidal signs, cognitive impairment and/or psychiatric symptoms. We describe an autopsy case of ALSP with a CSF1R mutation. A 61-year-old woman presented insidious-onset gait difficulty for 12 years since her age of 49, and premature ovarian failure since her age of 35. At initial hospital visit, brain magnetic resonance imaging revealed hydrocephalus. Initially, Parkinson's syndrome was diagnosed, and she was prescribed L-dopa/carbidopa because of spasticity and rigidity of extremities, which had worsened. Subsequently, severe neuropsychiatric symptoms and cognitive impairment developed and radiologically, features of leukoencephalopathy or leukodystrophy were detected. She showed a down-hill course and died, 12 years after initial diagnosis. At autopsy, the brain showed severe symmetric atrophy of bilateral white matter, paper-thin corpus callosum, thin internal capsule, and marked hydrocephalus. Microscopically, diffuse loss of white matter, relatively preserved subcortical U-fibers, and many eosinophilic bulbous neuroaxonal spheroids were noted, but there was no calcification. Pigmented glia with brown cytoplasmic pigmentation were readily found in the white matter, which were positive for Periodic acid-Schiff, p62, and CD163 stains, but almost negative for CD68. Whole-exome and Sanger sequencing revealed a CSF1R mutation (c.2539G>A, p.Glu847Lys) which was reported in prior one ALSP case. This example demonstrates that ALSP could be associated with premature ovarian failure.


Subject(s)
Atrophy , Autopsy , Axons , Brain , Cognition Disorders , Coloring Agents , Corpus Callosum , Cytoplasm , Diagnosis , Eosinophils , Extremities , Female , Gait , Humans , Hydrocephalus , Internal Capsule , Leukoencephalopathies , Magnetic Resonance Imaging , Middle Aged , Muscle Spasticity , Neuroglia , Parkinsonian Disorders , Pigmentation , Primary Ovarian Insufficiency , Protein-Tyrosine Kinases , White Matter
SELECTION OF CITATIONS
SEARCH DETAIL