ANA TEREZA DI LORENZO ALHO
Projetos de Pesquisa
Unidades Organizacionais
LIM/44 - Laboratório de Ressonância Magnética em Neurorradiologia, Hospital das Clínicas, Faculdade de Medicina
5 resultados
Resultados de Busca
Agora exibindo 1 - 5 de 5
- Magnetic resonance diffusion tensor imaging for the pedunculopontine nucleus: proof of concept and histological correlation(2017) ALHO, A. T. D. L.; HAMANI, C.; ALHO, E. J. L.; SILVA, R. E. da; SANTOS, G. A. B.; NEVES, R. C.; CARREIRA, L. L.; ARAUJO, C. M. M.; MAGALHAES, G.; COELHO, D. B.; ALEGRO, M. C.; MARTIN, M. G. M.; GRINBERG, L. T.; PASQUALUCCI, C. A.; HEINSEN, H.; FONOFF, E. T.; AMARO JR., E.The pedunculopontine nucleus (PPN) has been proposed as target for deep brain stimulation (DBS) in patients with postural instability and gait disorders due to its involvement in muscle tonus adjustments and control of locomotion. However, it is a deep-seated brainstem nucleus without clear imaging or electrophysiological markers. Some studies suggested that diffusion tensor imaging (DTI) may help guiding electrode placement in the PPN by showing the surrounding fiber bundles, but none have provided a direct histological correlation. We investigated DTI fractional anisotropy (FA) maps from in vivo and in situ postmortem magnetic resonance images (MRI) compared to histological evaluations for improving PPN targeting in humans. A post-mortem brain was scanned in a clinical 3T MR system in situ. Thereafter, the brain was processed with a special method ideally suited for cytoarchitectonic analyses. Also, nine volunteers had in vivo brain scanning using the same MRI protocol. Images from volunteers were compared to those obtained in the post-mortem study. FA values of the volunteers were obtained from PPN, inferior colliculus, cerebellar crossing fibers and medial lemniscus using histological data and atlas information. FA values in the PPN were significantly lower than in the surrounding white matter region and higher than in areas with predominantly gray matter. In Nissl-stained histologic sections, the PPN extended for more than 10 mm in the rostro-caudal axis being closely attached to the lateral parabrachial nucleus. Our DTI analyses and the spatial correlation with histological findings proposed a location for PPN that matched the position assigned to this nucleus in the literature. Coregistration of neuroimaging and cytoarchitectonic features can add value to help establishing functional architectonics of the PPN and facilitate neurosurgical targeting of this extended nucleus.
- High thickness histological sections as alternative to study the three-dimensional microscopic human sub-cortical neuroanatomy(2018) ALHO, Eduardo Joaquim Lopes; ALHO, Ana Tereza Di Lorenzo; GRINBERG, Lea; AMARO JR., Edson; SANTOS, Glaucia Aparecida Bento dos; SILVA, Rafael Emidio da; NEVES, Ricardo Caires; ALEGRO, Maryana; COELHO, Daniel Boari; TEIXEIRA, Manoel Jacobsen; FONOFF, Erich Talamoni; HEINSEN, HelmutStereotaxy is based on the precise image-guided spatial localization of targets within the human brain. Even with the recent advances in MRI technology, histological examination renders different (and complementary) information of the nervous tissue. Although several maps have been selected as a basis for correlating imaging results with the anatomical locations of sub-cortical structures, technical limitations interfere in a point-to-point correlation between imaging and anatomy due to the lack of precise correction for post-mortem tissue deformations caused by tissue fixation and processing. We present an alternative method to parcellate human brain cytoarchitectural regions, minimizing deformations caused by post-mortem and tissue-processing artifacts and enhancing segmentation by means of modified high thickness histological techniques and registration with MRI of the same specimen and into MNI space (ICBM152). A three-dimensional (3D) histological atlas of the human thalamus, basal ganglia, and basal forebrain cholinergic system is displayed. Structure's segmentations were performed in high-resolution dark-field and light-field microscopy. Bidimensional non-linear registration of the histological slices was followed by 3D registration with in situ MRI of the same subject. Manual and automated registration procedures were adopted and compared. To evaluate the quality of the registration procedures, Dice similarity coefficient and normalized weighted spectral distance were calculated and the results indicate good overlap between registered volumes and a small shape difference between them in both manual and automated registration methods. High thickness high-resolution histological slices in combination with registration to in situ MRI of the same subject provide an effective alternative method to study nuclear boundaries in the human brain, enhancing segmentation and demanding less resources and time for tissue processing than traditional methods.
- Locus coeruleus volume and cell population changes during Alzheimer's disease progression: A stereological study in human postmortem brains with potential implication for early-stage biomarker discovery(2017) THEOFILAS, Panos; EHRENBERG, Alexander J.; DUNLOP, Sara; ALHO, Ana T. Di Lorenzo; NGUY, Austin; LEITE, Renata Elaine Paraizo; RODRIGUEZ, Roberta Diehl; MEJIA, Maria B.; SUEMOTO, Claudia K.; FERRETTI-REBUSTINI, Renata Eloah De Lucena; POLICHISO, Livia; NASCIMENTO, Camila F.; SEELEY, William W.; NITRINI, Ricardo; PASQUALUCCI, Carlos Augusto; JACOB FILHO, Wilson; RUEB, Udo; NEUHAUS, John; HEINSEN, Helmut; GRINBERG, Lea T.Introduction: Alzheimer's disease (AD) progression follows a specific spreading pattern, emphasizing the need to characterize those brain areas that degenerate first. The brainstem's locus coeruleus (LC) is the first area to develop neurofibrillary changes (neurofibrillary tangles [NFTs]). Methods: The methods include unbiased stereologiCal analyses in human brainstems to estimate LC volume and neuronal population in controls and individuals across all AD stages. Results: As the Braak stage increases by 1 unit, the LC volume decreases by 8.4%. Neuronal loss started only midway through AD progression. Age-related changes spare the LC. Discussion: The long gap between NFT accumulation and neuronal loss suggests that a second trigger may be necessary to induce neuronal death in AD. Imaging studies should determine whether LC volumetry can replicate the stage-wise atrophy observed here and how these changes are specific to AD. LC volumetry may develop into a screening biomarker for selecting high-yield candidates to undergo expensive and less accessible positron emission tomography scans and to monitor AD progression from presymptomatic stages.
- Three-dimensional and stereological characterization of the human substantia nigra during aging(2016) ALHO, Ana Tereza Di Lorenzo; SUEMOTO, Claudia Kimie; POLICHISO, Livia; TAMPELLINI, Edilaine; OLIVEIRA, Katia Cristina de; MOLINA, Mariana; SANTOS, Glaucia Aparecida Bento; NASCIMENTO, Camila; LEITE, Renata Elaine Paraizo; FERRETI-REBUSTINI, Renata Eloah de Lucena; SILVA, Alexandre Valotta da; NITRINI, Ricardo; PASQUALUCCI, Carlos Augusto; JACOB-FILHO, Wilson; HEINSEN, Helmut; GRINBERG, Lea TenenholzThe human brain undergoes non-uniform changes during aging. The substantia nigra (SN), the source of major dopaminergic pathways in the brain, is particularly vulnerable to changes in the progression of several age-related neurodegenerative diseases. To establish normative data for high-resolution imaging, and to further clinical and anatomical studies we analyzed SNs from 15 subjects aged 50-91 cognitively normal human subjects without signs of parkinsonism. Complete brains or brainstems with substantia nigra were formalin-fixed, celloidin-mounted, serially cut and Nissl-stained. The shapes of all SNs investigated were reconstructed using fast, high-resolution computer-assisted 3D reconstruction software. We found a negative correlation between age and SN volume (p = 0.04, rho = -0.53), with great variability in neuronal numbers and density across participants. The 3D reconstructions revealed SN inter- and intra-individual variability. Furthermore, we observed that human SN is a neuronal reticulum, rather than a group of isolated neuronal islands. Caution is required when using SN volume as a surrogate for SN status in individual subjects. The use of multimodal sequences including those for fiber tracts may enhance the value of imaging as a diagnostic tool to assess SN in vivo. Further studies with a larger sample size are needed for understanding the structure-function interaction of human SN.
- Enrichment of single neurons and defined brain regions from human brain tissue samples for subsequent proteome analysis(2015) MOLINA, Mariana; STEINBACH, Simone; PARK, Young Mok; YUN, Su Yeong; ALHO, Ana Tereza Di Lorenzo; HEINSEN, Helmut; GRINBERG, Lea. T.; MARCUS, Katrin; LEITE, Renata E. Paraizo; MAY, CarolineBrain function in normal aging and neurological diseases has long been a subject of interest. With current technology, it is possible to go beyond descriptive analyses to characterize brain cell populations at the molecular level. However, the brain comprises over 100 billion highly specialized cells, and it is a challenge to discriminate different cell groups for analyses. Isolating intact neurons is not feasible with traditional methods, such as tissue homogenization techniques. The advent of laser microdissection techniques promises to overcome previous limitations in the isolation of specific cells. Here, we provide a detailed protocol for isolating and analyzing neurons from postmortem human brain tissue samples. We describe a workflow for successfully freezing, sectioning and staining tissue for laser microdissection. This protocol was validated by mass spectrometric analysis. Isolated neurons can also be employed for western blotting or PCR. This protocol will enable further examinations of brain cell-specific molecular pathways and aid in elucidating distinct brain functions.