Publications by authors named "Joao A Assirati"

Article Synopsis
  • - Meningiomas are the most common primary brain tumors, making up 43.8% of central nervous system tumors studied in a retrospective analysis of 993 patients, highlighting the need for understanding their demographic and geographic characteristics to guide treatment.
  • - The study revealed that operated patients had a mean age of 53 years while non-operated patients averaged 63.9 years, with a significant female predominance (up to 6.3:1) across various age groups, particularly in those not receiving surgery.
  • - The majority of meningiomas (96.5%) were found to be intracranial, mainly classified as WHO grade I, and there was a notable racial distribution with 87% Caucasian,
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Objective: Temporal lobe epilepsy patients (TLE) often present with hippocampal atrophy, increased T2 relaxation, and reduced magnetization transfer ratio (MTR) in magnetic resonance images (MRI). The histological correlates of the reduced hippocampal MTR are so far unknown. Since MTR is dependent on the tissue's macromolecules, our aim was to evaluate the correlations between cellular populations, extracellular matrix molecules and the MTR in TLE patients.

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Objective: Drebrins are crucial for synaptic function and dendritic spine development, remodeling, and maintenance. In temporal lobe epilepsy (TLE) patients, a significant hippocampal synaptic reorganization occurs, and synaptic reorganization has been associated with hippocampal hyperexcitability. This study aimed to evaluate, in TLE patients, the hippocampal expression of drebrin using immunohistochemistry with DAS2 or M2F6 antibodies that recognize adult (drebrin A) or adult and embryonic (pan-drebrin) isoforms, respectively.

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Mesial temporal lobe epilepsy with hippocampal sclerosis is the most frequent form of focal epilepsy in adults, and it is often refractory to drug treatment. Regardless of the efforts on developing new antiepileptic drugs for refractory cases, studies suggest a need for better understanding the molecular bases of epilepsy. The microRNAs have been progressively investigated as potential targets for both epilepsy mechanisms elucidation and treatment.

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The aim of this study was to analyze the expression profiles of the microRNAs (miRNAs) miR-145, miR-181c, miR-199a and miR-1183 in the hippocampus and blood of patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) and to investigate whether these can be used as diagnosis and prognosis biomarkers for epilepsy. Hippocampus and blood samples were collected from 20 patients with MTLE-HS, ten of whom had a favorable surgical outcome (Engel I) and ten with an unfavorable surgical outcome (Engel III-IV). Hippocampus samples from autopsied individuals with no neurological or psychiatric medical history (necropsy samples) and blood samples from healthy individuals were used as controls.

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In patients with temporal lobe epilepsy (TLE), presurgical magnetic resonance imaging (MRI) often reveals hippocampal atrophy, while neuropathological assessment indicates the different types of hippocampal sclerosis (HS). Different HS types are not discriminated in MRI so far. We aimed to define the volume of each hippocampal subfield on MRI manually and to compare automatic and manual segmentations for the discrimination of HS types.

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Background: Slice cultures have been prepared from several organs. With respect to the brain, advantages of slice cultures over dissociated cell cultures include maintenance of the cytoarchitecture and neuronal connectivity. Slice cultures from adult human brain have been reported and constitute a promising method to study neurological diseases.

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Growth hormone (GH) and the insulin-like growth factor I (IGF-I) have cell proliferative and differentiation properties. Whether these hormones have a role in mutagenesis is unknown. Nevertheless, severe IGF-I deficiency seems to confer protection against the development of neoplasms.

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Objective: Increased T2 relaxation time is often seen in temporal lobe epilepsy (TLE) with hippocampal sclerosis. Water content directly affects the effective T2 in a voxel. Our aim was to evaluate the relation between T2 values and two molecules associated with brain water homeostasis aquaporin 4 (AQP4) and chondroitin sulfate proteoglycan (CSPG), as well as cellular populations in the hippocampal region of patients with TLE.

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Objective: Hippocampal sclerosis is a common finding in patients with temporal lobe epilepsy (TLE), and magnetic resonance imaging (MRI) studies associate the reduction of hippocampal volume with the neuron loss seen on histologic evaluation. Astrogliosis and increased levels of chondroitin sulfate, a major component of brain extracellular matrix, are also seen in hippocampal sclerosis. Our aim was to evaluate the association between hippocampal volume and chondroitin sulfate, as well as neuronal and astroglial populations in the hippocampus of patients with TLE.

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Background: Despite the strong association between epilepsy and psychiatric comorbidities, few biological substrates are currently described. We have previously reported neuropathological alterations in mesial temporal lobe epilepsy (MTLE) patients with major depression and psychosis that suggest a morphological and neurochemical basis for psychopathological symptoms. Neuroinflammatory-related structures and molecules might be part of the altered neurochemical milieu underlying the association between epilepsy and psychiatric comorbidities, and such features have not been previously investigated in humans.

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Objective: Biologic substrates behind the close association between mesial temporal lobe epilepsy (MTLE) and psychiatric comorbidities are largely unknown. Heat shock protein 70 (HSP70) and HSP90 are ubiquitous molecular chaperones that play important roles in functions from cellular stress response to receptor trafficking control. There are controversial findings regarding HSP expression in epilepsy.

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Epilepsy and psychiatric comorbidities are frequently associated, but their common biological substrate is unknown. We have previously reported altered structural elements and neurotrophins (NTs) expression in mesial temporal lobe epilepsy (MTLE) patients with psychiatric comorbidities. NTs receptors can regulate neurotransmission and promote neuroplasticity, being important candidates in the regulation and manifestation of psychopatological states and seizure-related events.

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Despite the strong association between epilepsy and psychiatric comorbidities, data on clinicopathologic correlations are scant. We previously reported differential mossy fiber sprouting (MFS) in mesial temporal lobe epilepsy (MTLE) patients with psychosis (MTLE + P) and major depression (MTLE + D). Because neurotrophins (NTs) can promote MFS, here, we investigated MFS, neuronal density and immunoreactivity for the NT nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT3) in hippocampi of 14 MTLE patients without a psychiatric history, 13 MTLE + D, 13 MTLE + P, and 10 control necropsies.

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Background: Despite strong association between epilepsy and psychiatric comorbidities, biological substrates are unknown. We have previously reported decreased mossy fiber sprouting in mesial temporal lobe epilepsy (MTLE) patients with psychosis and increased in those with major depression. Microtubule associated proteins (MAPs) are essentially involved in dendritic and synaptic sprouting.

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Metabotropic glutamate receptor type 5 (mGluR5) upregulation in temporal lobe epilepsy (TLE) and the correlation of its expression with features of hippocampal sclerosis (HS) remains unclear. Here we characterized mGluR5 immunoreactivity in hippocampus, entorhinal cortex (EC), and subiculum of TLE specimens with confirmed HS, with neocortical TLE (non-HS) and necropsy controls. We correlated mGluR5 immunoreactivity with neuronal density, mossy fiber sprouting, astrogliosis (GFAP), and dendritic alterations (MAP2).

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Background: Where neurocysticercosis (NCC) is endemic, chronic calcified neurocysticercosis (cNCC) can be observed in patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS). Considering that both disorders cause recurrent seizures or cognitive impairment, we evaluated if temporal lobectomy is cognitively safe and effective for seizure control in MTLE-HS plus cNCC.

Methods: Retrospective cohort study of neuropsychological profile and surgical outcome of 324 MTLE-HS patients submitted to temporal lobectomy, comparing the results according to the presence or absence of cNCC.

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Patients with left mesial temporal lobe epilepsy (MTLE) have deficits in verbal memory processes, while patients with right MTLE have visuospatial memory impairment. However, atypical cognitive phenotypes among patients with MTLE may occur. In this study, we analyzed preoperative memory deficits in a cohort of 426 right-handed patients with unilateral MTLE.

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Purpose: To investigate the prognostic value of ictal scalp EEG patterns in drug-resistant temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) prior to undergoing temporal lobectomy.

Methods: Scalp EEGs of the first seizure recorded during presurgical long-term video-EEG monitoring of 284 patients were reviewed. Patients were divided according to seizure laterality as either unilateral, when the EEG was restricted to one cerebral hemisphere for the entire seizure, or bilateral, when there was involvement of both hemispheres during the seizure.

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We studied the prevalence and associated factors of psychiatric comorbidities in 490 patients with refractory focal epilepsy. Of these, 198 (40.4%) patients had psychiatric comorbidity.

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In the central nervous system, zinc is released along with glutamate during neurotransmission and, in excess, can promote neuronal death. Experimental studies have shown that metallothioneins I/II (MT-I/II), which chelate free zinc, can affect seizures and reduce neuronal death after status epilepticus. Our aim was to evaluate the expression of MT-I/II in the hippocampus of patients with temporal lobe epilepsy (TLE).

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The term "paraclinoid aneurysms", has been used for aneurysms of the internal carotid artery (ICA) between the cavernous sinus and the posterior communicating artery. Due to their complex anatomical relationship at the skull base and because they are frequently large/giant, their surgical treatment remains a challenge. Ninety-five patients harboring 106 paraclinoid aneurysms underwent surgery (1990-2010).

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The objectives of the study were to translate and adapt the Subjective Handicap of Epilepsy (SHE) instrument to Brazilian Portuguese and to determine its psychometric properties for the evaluation of quality of life in patients with epilepsy. A sample of 448 adult patients with epilepsy with different clinical profiles (investigation, preoperative period, postoperative period, and drug treatment follow-up) was evaluated with the SHE and the Epilepsy Surgery Inventory (ESI-55). Exploratory factorial analysis demonstrated that four factors explained 60.

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Purpose: Refractory frontal lobe epilepsy (FLE) remains one of the most challenging surgically remediable epilepsy syndromes. Nevertheless, definition of independent predictors and predictive models of postsurgical seizure outcome remains poorly explored in FLE.

Methods: We retrospectively analyzed data from 70 consecutive patients with refractory FLE submitted to surgical treatment at our center from July 1994 to December 2006.

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