Publications by authors named "Juliana Ben"

22 Publications

  • Page 1 of 1

Employment status as a major determinant for lower physical activity of patients with epilepsy: A case-control study.

Epilepsy Behav 2021 Feb 17;115:107655. Epub 2020 Dec 17.

Medical Sciences Graduate Program, Federal University of Santa Catarina (UFSC), Florianópolis, SC, Brazil; Neurology Division, Federal University of Santa Catarina (UFSC), Florianópolis, SC, Brazil; Center for Applied Neurosciences (CeNAp), Federal University of Santa Catarina (UFSC), Florianópolis, SC, Brazil. Electronic address:

Background: People with epilepsy (PWE) may have a sedentary lifestyle and less physical activity (PA) as they are often advised against engaging in sports, despite a plethora of evidence suggesting seizure control, major health and psychosocial benefits associated with PA. We aimed to investigate PWE's beliefs on PA and their level of PA compared to controls.

Methods: The Baecke questionnaire for measuring habitual PA in adults, comprising three domains (occupational PA, leisure, and locomotion), was applied in 97 consecutive PWE (96.9% with focal epilepsy, 39.2% well controlled with pharmacological treatment) and 45 healthy controls matched for gender, age, and socioeconomic characteristics.

Results: The total Baecke score was significantly lower in PWE than controls (7.6 ± 1.5 versus 8.2 ± 1.2; p < 0.01). PWE showed a significantly lower employment rate than controls (34.0% versus 73.3%; p < 0.01), and consequently lower occupational PA (p < 0.01). Physical exercise during sports time (p = 0.23) and leisure activities (p = 0.55) scores were similar between patients and controls. When PWE and controls' sociodemographic characteristics were analyzed together by multiple linear regression, 21% of the Baecke total score variation was explained by diagnosis of epilepsy (B = -0.26; p = 0.05), years of education (B = -0.35; p = 0.03), and occupational status (B = -0.41; p < 0.01). However, diagnosis of epilepsy alone explained only 4% (B = -0.64; p = 0.01) of Baecke total score variation.

Conclusion: The level of PA in PWE is only slightly lower than in controls (8% lower score) and it may be explained by lower occupational PA, probably related to lower employment rate among PWE.
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http://dx.doi.org/10.1016/j.yebeh.2020.107655DOI Listing
February 2021

Is self-report sleepiness associated with cognitive performance in temporal lobe epilepsy?

Arq Neuropsiquiatr 2018 09;76(9):575-581

Universidade Federal de Santa Catarina, Hospital Universitário, Departamento de Clínica Médica, Serviço de Neurologia, Florianópolis SC, Brasil.

Objectives: Sleepiness and cognitive impairment are common symptoms observed in patients with epilepsy. We investigate whether self-reported sleepiness is associated with cognitive performance in patients with refractory mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). Seventy-one consecutive patients with MTLE-HS were evaluated with the Stanford Sleepiness Scale (SSS) before neuropsychological evaluation. Their mean SSS scores were compared with controls. Each cognitive test was compared between patients with (SSS ≥ 3) or without sleepiness (SSS < 3). Imbalances were controlled by regression analysis. Patients reported a significantly higher degree of sleepiness than controls (p < 0.0001). After multiple linear regression analysis, only one test (RAVLT total) remained associated with self-reported sleepiness.

Conclusion: Self-reported sleepiness was significantly higher in MTLE-HS patients than controls, but did not affect their cognitive performance. If confirmed in other populations, our results may have implications for decision making about sleepiness screening in neuropsychological settings.
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http://dx.doi.org/10.1590/0004-282X20180089DOI Listing
September 2018

Neuropsychological functioning and brain energetics of drug resistant mesial temporal lobe epilepsy patients.

Epilepsy Res 2017 12 12;138:26-31. Epub 2017 Oct 12.

Centro de Neurociências Aplicadas, Hospital Universitário (HU), Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, Brazil; Centro de Epilepsia do Estado de Santa Catarina, CEPESC, HU, UFSC, Florianópolis, SC, Brazil; Serviço de Neurologia, Departamento de Clínica Médica, HU, UFSC, Florianópolis, SC, Brazil. Electronic address:

Interictal hypometabolism is commonly measured by 18-fluoro-deoxyglucose Positron Emission Tomography (FDG-PET) in the temporal lobe of patients with mesial temporal lobe epilepsy (MTLE-HS). Left temporal lobe interictal FDG-PET hypometabolism has been associated with verbal memory impairment, while right temporal lobe FDG-PET hypometabolism is associated with nonverbal memory impairment. The biochemical mechanisms involved in these findings remain unknown. In comparison to healthy controls (n=21), surgically treated patients with MTLE-HS (n=32, left side=17) had significant lower scores in the Rey Auditory Verbal Learning Test (RAVLT retention and delayed), Logical Memory II (LMII), Boston Naming test (BNT), Letter Fluency and Category Fluency. We investigated whether enzymatic activities of the mitochondrial enzymes Complex I (C I), Complex II (C II), Complex IV (C IV) and Succinate Dehydrogenase (SDH) from the resected samples of the middle temporal neocortex (mTCx), amygdala (AMY) and hippocampus (HIP) were associated with performance in the RAVLT, LMII, BNT and fluency tests of our patients. After controlling for the side of hippocampus sclerosis, years of education, disease duration, antiepileptic treatment and seizure outcome after surgery, no independent associations were observed between the cognitive test scores and the analyzed mitochondrial enzymatic activities (p>0.37). Results indicate that memory and language impairment observed in MTLE-HS patients are not strongly associated with the levels of mitochondrial CI, CII, SDH and C IV enzymatic activities in the temporal lobe structures ipsilateral to the HS lesion.
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http://dx.doi.org/10.1016/j.eplepsyres.2017.10.009DOI Listing
December 2017

Decline in word-finding: The objective cognitive finding most relevant to patients after mesial temporal lobe epilepsy surgery.

Epilepsy Behav 2017 10 1;75:218-224. Epub 2017 Sep 1.

Centro de Neurociências Aplicadas (CeNAp), Hospital Universitário (HU), Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, Brazil; Serviço de Neurologia, Departamento de Clínica Médica, HU-UFSC, Florianópolis, SC, Brazil; Centro de Epilepsia de Santa Catarina (CEPESC), HU-UFSC, Florianópolis, SC, Brazil. Electronic address:

Purpose: The purpose of this study was to investigate the following: i) the objective impairment in neuropsychological tests that were associated with the subjective perception of cognitive function decline in Brazilian patients who underwent mesial temporal lobe epilepsy (MTLE) surgery and ii) the predictive variables for those impaired objective neuropsychological tests.

Methods: Forty-eight adults with MTLE (27 right HS and 23 male) were divided according to their perception of changes (Decline or No-decline) of cognitive function domain of the QOLIE-31 questionnaire applied before and 1year after the ATL. The mean (SD) of changes in the raw score difference of the neuropsychological tests before and after the ATL was compared between Decline and No-decline groups. Receiver Operating Characteristic curves, sensitivity, specificity, and predictive values were used to assess the optimum cutoff points of neuropsychological test score changes to predict patient-reported subjective cognitive decline.

Key Findings: Six (12.5%) patients reported a perception of cognitive function decline after ATL. Among the 25 cognitive tests analyzed, only changes in the Boston Naming Test (BNT) were associated with subjective cognitive decline reported by patients. A reduction of ≥8 points in the raw score of BNT after surgery had 91% of sensitivity and 45% specificity for predicting subjective perception of cognitive function decline by the patient. Left side surgery and age older than 40years were more associated with an important BNT reduction with overall accuracy of 91.7%, 95% predictive ability for no impairment, and 75% for impairment of cognitive function.

Significance: Impairment in word-finding seems to be the objective cognitive finding most relevant to Brazilian patients after mesial temporal lobe epilepsy surgery. Similar to American patients, the side of surgery and age are good predictors for no decline in the BNT, but shows a lower accuracy to predict its decline. If replicated in other populations, the results may have wider implications for the surgical management of patients with drug-resistant MTLE.
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http://dx.doi.org/10.1016/j.yebeh.2017.08.012DOI Listing
October 2017

Predictors of meaningful improvement in quality of life after temporal lobe epilepsy surgery: A prospective study.

Epilepsia 2017 05 23;58(5):755-763. Epub 2017 Mar 23.

Center for Applied Neurosciences (CeNAp), University Hospital (HU), Federal University of Santa Catarina State (UFSC), Florianópolis, Santa Catarina, Brazil.

Objectives: To investigate prospectively the independent predictors of a minimum clinically important change (MCIC) in quality of life (QOL) after anterior temporal lobectomy (ATL) for drug-resistant mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) in Brazilian patients.

Methods: Multiple binary logistic regression analysis was performed to identify the clinical, demographic, radiologic, and electrophysiologic variables independently associated with MCIC in the Quality of Life in Epilepsy-31 Inventory (QOLIE-31) overall score 1 year after ATL in 77 consecutive patients with unilateral MTLE-HS.

Results: The overall QOLIE-31 score and all its subscale scores increased significantly (p < 0.0001) 1 year after ATL. In the final logistic regression model, absence of presurgical diagnosis of depression (adjusted odds ratio [OR] 4.4, 95% confidence interval [CI] 1.1-16.1, p = 0.02) and a complete postoperative seizure control (adjusted OR 4.1, 95% CI 1.2-14.5, p = 0.03) were independently associated with improvement equal to or greater than the MCIC in QOL after ATL. The overall model accuracy for MCIC improvement in the QOL was 85.6%, with a 95.2% of sensitivity and 46.7% of specificity.

Significance: These results in Brazilian patients reinforce the external validation of previous findings in Canadian patients showing that presurgical depression and complete seizure control after surgery are independent predictors for meaningful improvement in QOL after ATL, and have implications for the surgical management of MTLE patients.
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http://dx.doi.org/10.1111/epi.13721DOI Listing
May 2017

Moderate traumatic brain injury increases the vulnerability to neurotoxicity induced by systemic administration of 6-hydroxydopamine in mice.

Brain Res 2017 05 11;1663:78-86. Epub 2017 Mar 11.

Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis 88049-900, Brazil; Programa de Pós-Graduação em Neurociências, Universidade Federal de Santa Catarina, Florianópolis 88049-900, Brazil. Electronic address:

Moderate traumatic brain injury (TBI) might increase the vulnerability to neuronal neurodegeneration, but the basis of such selective neuronal susceptibility has remained elusive. In keeping with the disruption of the blood-brain barrier (BBB) caused by TBI, changes in BBB permeability following brain injury could facilitate the access of xenobiotics into the brain. To test this hypothesis, here we evaluated whether TBI would increase the susceptibility of nigrostriatal dopaminergic fibers to the systemic administration of 6-hydroxydopamine (6-OHDA), a classic neurotoxin used to trigger a PD-like phenotype in mice, but that in normal conditions is unable to cross the BBB. Adult Swiss mice were submitted to a moderate TBI using a free weight-drop device and, 5h later, they were injected intraperitoneally with a single dose of 6-OHDA (100mg/kg). Afterwards, during a period of 4weeks, the mice were submitted to a battery of behavioral tests, including the neurological severity score (NSS), the open field and the rotarod. Animals from the TBI plus 6-OHDA group displayed significant motor and neurological impairments that were improved by acute l-DOPA administration (25mg/kg, i.p.). Moreover, the observation of the motor deficits correlates with (i) a significant decrease in the tyrosine hydroxylase levels mainly in the rostral striatum and (ii) a significant increase in the levels of striatal glial fibrillary acidic protein (GFAP) levels. On the whole, the present findings demonstrate that a previous moderate TBI event increases the susceptibility to motor, neurological and neurochemical alterations induced by systemic administration of the dopaminergic neurotoxin 6-OHDA in mice.
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http://dx.doi.org/10.1016/j.brainres.2017.03.002DOI Listing
May 2017

Deep brain stimulation improves gait velocity in Parkinson's disease: a systematic review and meta-analysis.

J Neurol 2016 Jun 28;263(6):1195-203. Epub 2016 Apr 28.

Department of Applied Physiology and Kinesiology, University of Florida, 100 Florida Gym, PO Box 118205, Gainesville, FL, 32611-8205, USA.

In Parkinson's disease (PD), slow gait speed is significantly related to clinical ratings of disease severity, impaired performance of daily activities, as well as increased overall disability. Conducting a meta-analysis on gait speed is an objective and quantitative technique to summarize the effectiveness of DBS and to determine the effect sizes for future studies. We conducted a systematic review and meta-analysis that analyzed the effects of deep brain stimulation (DBS) surgery on gait speed in patients with PD to gain fundamental insight into the nature of therapeutic effectiveness. A random effects model meta-analysis on 27 studies revealed a significant overall standardized mean difference medium effect size equal to 0.60 (SE = 0.06; p < 0.0001; Z = 10.58). Based on our synthesis of the 27 studies, we determined the following: (1) a significant and medium effect size indicating DBS improves gait speed; (2) DBS improved gait speed regardless of whether the patients were tested in the on or off medication state; (3) both bilateral and unilateral DBS led to gait speed improvement; (4) the effects of DBS on gait speed in the data collection sessions after surgery (DBS on vs. off) were comparable with data collection before surgery (before surgery vs. DBS after surgery); and (5) when evaluating the effects of DBS and medication on gait speed suprathreshold doses were comparable to normal dosages of medication and DBS. The current analysis provides objective evidence that both unilateral and bilateral DBS provide a therapeutic benefit on gait speed in persons with PD.
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http://dx.doi.org/10.1007/s00415-016-8129-9DOI Listing
June 2016

Decreased synaptic plasticity in the medial prefrontal cortex underlies short-term memory deficits in 6-OHDA-lesioned rats.

Behav Brain Res 2016 Mar 18;301:43-54. Epub 2015 Dec 18.

Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis 88049-900, SC, Brazil; Centro de Neurociências Aplicadas (CeNAp), Hospital Universitário (HU), Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil. Electronic address:

Parkinson's disease (PD) is characterized by motor dysfunction associated with dopaminergic degeneration in the dorsolateral striatum (DLS). However, motor symptoms in PD are often preceded by short-term memory deficits, which have been argued to involve deregulation of medial prefrontal cortex (mPFC). We now used a 6-hydroxydopamine (6-OHDA) rat PD model to explore if alterations of synaptic plasticity in DLS and mPFC underlie short-term memory impairments in PD prodrome. The bilateral injection of 6-OHDA (20μg/hemisphere) in the DLS caused a marked loss of dopaminergic neurons in the substantia nigra (>80%) and decreased monoamine levels in the striatum and PFC, accompanied by motor deficits evaluated after 21 days in the open field and accelerated rotarod. A lower dose of 6-OHDA (10μg/hemisphere) only induced a partial degeneration (about 60%) of dopaminergic neurons in the substantia nigra with no gross motor impairments, thus mimicking an early premotor stage of PD. Notably, 6-OHDA (10μg)-lesioned rats displayed decreased monoamine levels in the PFC as well as short-term memory deficits evaluated in the novel object discrimination and in the modified Y-maze tasks; this was accompanied by a selective decrease in the amplitude of long-term potentiation in the mPFC, but not in DLS, without changes of synaptic transmission in either brain regions. These results indicate that the short-term memory dysfunction predating the motor alterations in the 6-OHDA model of PD is associated with selective changes of information processing in PFC circuits, typified by persistent changes of synaptic plasticity.
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http://dx.doi.org/10.1016/j.bbr.2015.12.011DOI Listing
March 2016

Developmental exposure to manganese induces lasting motor and cognitive impairment in rats.

Neurotoxicology 2015 Sep 26;50:28-37. Epub 2015 Jul 26.

Programa de Pós-graduação em Neurociências, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil; Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil. Electronic address:

Exposure to high manganese (Mn) levels may damage the basal ganglia, leading to a syndrome analogous to Parkinson's disease, with motor and cognitive impairments. The molecular mechanisms underlying Mn neurotoxicity, particularly during development, still deserve further investigation. Herein, we addressed whether early-life Mn exposure affects motor coordination and cognitive function in adulthood and potential underlying mechanisms. Male Wistar rats were exposed intraperitoneally to saline (control) or MnCl2 (5, 10 or 20 mg/kg/day) from post-natal day (PND) 8-12. Behavioral tests were performed on PND 60-65 and biochemical analysis in the striatum and hippocampus were performed on PND14 or PND70. Rats exposed to Mn (10 and 20 mg/kg) performed significantly worse on the rotarod test than controls indicating motor coordination and balance impairments. The object and social recognition tasks were used to evaluate short-term memory. Rats exposed to the highest Mn dose failed to recognize a familiar object when replaced by a novel object as well as to recognize a familiar juvenile rat after a short period of time. However, Mn did not alter olfactory discrimination ability. In addition, Mn-treated rats displayed decreased levels of non-protein thiols (e.g. glutathione) and increased levels of glial fibrillary acidic protein (GFAP) in the striatum. Moreover, Mn significantly increased hippocampal glutathione peroxidase (GPx) activity. These findings demonstrate that acute low-level exposure to Mn during a critical neurodevelopmental period causes cognitive and motor dysfunctions that last into adulthood, that are accompanied by alterations in antioxidant defense system in both the hippocampus and striatum.
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http://dx.doi.org/10.1016/j.neuro.2015.07.005DOI Listing
September 2015

Effects of pentylenetetrazole kindling on mitogen-activated protein kinases levels in neocortex and hippocampus of mice.

Neurochem Res 2014 Dec 15;39(12):2492-500. Epub 2014 Oct 15.

Programa de Pós-Graduação em Neurociências, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.

The epileptogenesis process involves cell signaling events associated with neuroplasticity. The mitogen-activated protein kinases (MAPKs) integrate signals originating from a variety of extracellular stimuli and may regulate cell differentiation, survival, cell death and synaptic plasticity. Here we compared the total and phosphorylated MAPKs (ERK1/2, JNK1/2 and p38(MAPK)) levels in the neocortex and hippocampus of adult Swiss male mice quantified by western blotting analysis 48 h after the last injection of pentylenetetrazole (PTZ), according to the kindling protocol (35 mg/kg, i.p., on alternated days, with a total of eight injections). The total levels of the investigated MAPKs and the phospho-p38(MAPK) in the neocortex and hippocampus were not affected by the PTZ injections. The MAPKs phosphorylation levels remain unaltered in PTZ-treated animals without convulsive seizures. The phospho-JNK2 phosphorylation, but not the phospho-JNK1, was increased in the hippocampus of PTZ-treated animals showing 1-3 days with convulsive seizures, whereas no significant changes were observed in those animals with more than 3 days with convulsive seizures. The phospho-ERK1/2 phosphorylation decreased in the neocortex and increased in the hippocampus of animals with 1-4 days with convulsive seizures and became unaltered in mice that showed convulsive seizures for more than 4 days. These findings indicate that resistance to PTZ kindling is associated with unaltered ERK1/2, JNK1/2 and p38(MAPK) phosphorylation levels in the neocortex and hippocampus. Moreover, when the PTZ kindling-induced epileptogenesis manifests behaviorally, the activation of the different MAPKs sub-families shows a variable and non-linear pattern in the neocortex and hippocampus.
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http://dx.doi.org/10.1007/s11064-014-1453-5DOI Listing
December 2014

Role of agmatine in neurodegenerative diseases and epilepsy.

Front Biosci (Elite Ed) 2014 Jun 1;6:341-59. Epub 2014 Jun 1.

Departamento de Farmacologia, Centro de Ciencias Biologicas, Universidade Federal de Santa Catarina, UFSC, Florianopolis, SC, Brazil.

Agmatine, a cationic polyamine synthesized after decarboxylation of L-arginine by the enzyme arginine decarboxylase, is an endogenous neuromodulator that emerges as a potential agent to manage diverse central nervous system (CNS) disorders. Consistent with its neuromodulatory and neuroprotective properties, there is increasing number of preclinical studies demonstrating the beneficial effects of exogenous agmatine administration on depression, anxiety, hypoxic ischemia, nociception, morphine tolerance, memory, Parkinson`s disease, Alzheimer`s disease, traumatic brain injury related alterations/disorders and epilepsy. The aim of this review is to summarize the knowledge about the effects of agmatine in CNS and point out its potential as new pharmacological treatment for diverse neurological and neurodegenerative diseases. Moreover, some molecular mechanisms underlying the neuroprotective effects of agmatine will be discussed.
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June 2014

Role of hormonal levels on hospital mortality for male patients with severe traumatic brain injury.

Brain Inj 2014 19;28(10):1262-9. Epub 2014 May 19.

Centro de Neurociências Aplicadas (CeNAp) .

Introduction: Changes in hormone blood levels during the acute phase of traumatic brain injury (TBI) have been described in the literature. The objective was to investigate the association among several hormones plasma levels in the acute phase of severe TBI and the hospital mortality rate of male patients.

Methods: The independent association among plasma levels of TSH, LH, FSH, GH, free T4, cortisol, IGF-1 and total testosterone was measured 10 hours and 30 hours after severe TBI and the hospital mortality of 60 consecutive male patients was evaluated.

Results: At least one hormonal level abnormality was demonstrated in 3.6-73.1% of patients. The multiple logistic regressions showed a trend for an independent association among hospital mortality and normal or elevated LH levels measured at 10 hours (OR = 3.7, 95% CI = 0.8-16.3, p = 0.08) and 30 hours (OR = 3.9, 95% CI = 0.9-16.7, p = 0.06). Admission with abnormal pupils and a lower Glasgow Coma Score also were independently associated with hospital mortality.

Conclusion: The hormonal changes are frequent in the acute phase of severe TBI. The hormones plasma levels, excepting the LH, are not highly consistent with the hospital mortality of male patients.
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http://dx.doi.org/10.3109/02699052.2014.915986DOI Listing
November 2015

Vatairea macrocarpa lectin (VML) induces depressive-like behavior and expression of neuroinflammatory markers in mice.

Neurochem Res 2013 Nov 12;38(11):2375-84. Epub 2013 Sep 12.

Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.

Lectins are proteins capable of reversible binding to the carbohydrates in glycoconjugates that can regulate many physiological and pathological events. Galectin-1, a β-galactoside-binding lectin, is expressed in the central nervous system (CNS) and exhibits neuroprotective functions. Additionally, lectins isolated from plants have demonstrated beneficial action in the CNS. One example is a lectin with mannose-glucose affinity purified from Canavalia brasiliensis seeds, ConBr, which displays neuroprotective and antidepressant activity. On the other hand, the effects of the galactose-binding lectin isolated from Vatairea macrocarpa seeds (VML) on the CNS are largely unknown. The aim of this study was to verify if VML is able to alter neural function by evaluating signaling enzymes, glial and inflammatory proteins in adult mice hippocampus, as well as behavioral parameters. VML administered by intracerebroventricular (i.c.v) route increased the immobility time in the forced swimming test (FST) 60 min after its injection through a carbohydrate recognition domain-dependent mechanism. Furthermore, under the same conditions, VML caused an enhancement of COX-2, GFAP and S100B levels in mouse hippocampus. However, phosphorylation of Akt, GSK-3β and mitogen-activated protein kinases named ERK1/2, JNK1/2/3 and p38(MAPK), was not changed by VML. The results reported here suggest that VML may trigger neuroinflammatory response in mouse hippocampus and exhibit a depressive-like activity. Taken together, our findings indicate a dual role for galactose binding lectins in the modulation of CNS function.
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http://dx.doi.org/10.1007/s11064-013-1150-9DOI Listing
November 2013

Chronic brain hypoperfusion causes early glial activation and neuronal death, and subsequent long-term memory impairment.

Brain Res Bull 2012 Jan 21;87(1):109-16. Epub 2011 Oct 21.

Programa de Pós-graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2600, 90050-170, Porto Alegre, RS, Brazil.

Reduction of cerebral blood flow is an important risk factor for dementia states and other brain dysfunctions. In present study, the effects of permanent occlusion of common carotid arteries (2VO), a well established experimental model of brain ischemia, on memory function were investigated, as assessed by reference and working spatial memory protocols and the object recognition task; cell damage to the hippocampus, as measured through changes in immunoreactivity for GFAP and the neuronal marker NeuN was also studied. The working hypothesis is that metabolic impairment following hypoperfusion will affect neuron and glial function and result in functional damage. Adult male Wistar rats were submitted to the modified 2VO method, with the right common carotid artery being occluded first and the left one week later, and tested seven days, three and six months after the ischemic event. A significant cognitive deficit was found in both reference and working spatial memory, as well as in the object recognition task, three and six months after surgery. Neuronal death and reactive astrogliosis were already present at 7 days and continued for up to 3 months after the occlusion; interestingly, there was no significant reduction in hippocampal volume. Present data suggests that cognitive impairment caused by brain hypoperfusion is long - lasting and persists beyond the time point of recovery from glial activation and neuronal loss.
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http://dx.doi.org/10.1016/j.brainresbull.2011.10.006DOI Listing
January 2012

Forced treadmill exercise prevents oxidative stress and memory deficits following chronic cerebral hypoperfusion in the rat.

Neurobiol Learn Mem 2012 Jan 7;97(1):90-6. Epub 2011 Oct 7.

Programa de Pós-graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Brazil.

Physical activity impacts functional recovery following stroke in humans, however its effects in experimental animals submitted to chronic cerebral hypoperfusion have not been investigated. The aim of this study was to evaluate the therapeutic potential of exercise, as assessed by cognitive activity in the Morris water maze and the brain oxidative status, through measurement of macromolecules damage, TBARS levels and total cellular thiols, as well as antioxidant enzymes in hippocampus, striatum and cerebral cortex. Adult male Wistar rats were submitted to the modified permanent bilateral occlusion of the common carotid arteries (2VO) method, with right common carotid artery being first occluded, and tested 3 months after the ischemic event. The effects of three different exercise protocols were examined: pre-ischemia, post-ischemia and pre+post-ischemia. Physical exercise consisted of sessions of 20-min, 3 times per week during 12 weeks (moderate intensity). Rats were submitted to cognitive assessment, in both reference and working spatial memory and after the last testing session were sacrificed to have oxidative stress parameters determined. Hypoperfusion caused a significant cognitive deficit in both spatial water maze tasks and this effect was reversed in rats receiving exercise protocol post and pre+post the ischemic event. Moreover, forced regular treadmill exercise regulated oxidative damage and antioxidant enzyme activity in the hippocampus. These results suggest that physical exercise protects against cognitive and biochemical impairments caused by chronic cerebral hypoperfusion.
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http://dx.doi.org/10.1016/j.nlm.2011.09.008DOI Listing
January 2012

The beneficial effects of treadmill step training on activity-dependent synaptic and cellular plasticity markers after complete spinal cord injury.

Neurochem Res 2011 Jun 22;36(6):1046-55. Epub 2011 Mar 22.

Programa de Pós-Graduação em Neurociências, ICBS, Universidade Federal do Rio Grande do Sul, R Sarmento Leite 500, Porto Alegre, RS 90050-170, Brazil.

Several studies have shown that treadmill training improves neurological outcomes and promotes plasticity in lumbar spinal cord of spinal animals. The morphological and biochemical mechanisms underlying these phenomena remain unclear. The purpose of this study was to provide evidence of activity-dependent plasticity in spinal cord segment (L5) below a complete spinal cord transection (SCT) at T8-9 in rats in which the lower spinal cord segments have been fully separated from supraspinal control and that subsequently underwent treadmill step training. Five days after SCT, spinal animals started a step-training program on a treadmill with partial body weight support and manual step help. Hindlimb movements were evaluated over time and scored on the basis of the open-field BBB scale and were significantly improved at post-injury weeks 8 and 10 in trained spinal animals. Treadmill training also showed normalization of withdrawal reflex in trained spinal animals, which was significantly different from the untrained animals at post-injury weeks 8 and 10. Additionally, compared to controls, spinal rats had alpha motoneuronal soma size atrophy and reduced synaptophysin protein expression and Na(+), K(+)-ATPase activity in lumbar spinal cord. Step-trained rats had motoneuronal soma size, synaptophysin expression and Na(+), K(+)-ATPase activity similar to control animals. These findings suggest that treadmill step training can promote activity-dependent neural plasticity in lumbar spinal cord, which may lead to neurological improvements without supraspinal descending control after complete spinal cord injury.
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http://dx.doi.org/10.1007/s11064-011-0446-xDOI Listing
June 2011

Running exercise effects on spatial and avoidance tasks in ovariectomized rats.

Neurobiol Learn Mem 2010 Oct 24;94(3):312-7. Epub 2010 Jul 24.

Laboratório de Neuroproteção e Doença Metabólica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Brazil.

Since previous studies have shown that ovariectomy impairs memory and cognition, we investigated whether physical exercise would affect ovariectomy-induced memory deficits in inhibitory avoidance and Morris water maze tasks. Female adult Wistar rats were assigned to one of the following groups: sham (submitted to surgery without removal of the ovaries), exercise, ovariectomy (Ovx) and Ovx plus exercise. Thirty days after ovariectomy or sham surgery, animals were submitted to 1 month of treadmill exercise training for 20 min, three times per week. Rats were than tested in inhibitory avoidance and Morris water maze tasks in order to verify ovariectomy effects on aversive and spatial memory performance. Results show that ovariectomized rats were impaired in aversive memory and spatial navigation, both in reference and working memory protocols. Confirming the working hypothesis, ovariectomized rats submitted to exercise had those impairments prevented. These findings support that physical exercise might constitute an important strategy to minimize cognitive deficits found in post-menopausal women.
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http://dx.doi.org/10.1016/j.nlm.2010.07.003DOI Listing
October 2010

Exercise effects on activities of Na(+),K(+)-ATPase, acetylcholinesterase and adenine nucleotides hydrolysis in ovariectomized rats.

Brain Res 2009 Dec 11;1302:248-55. Epub 2009 Sep 11.

Laboratório de Neuroproteção e Doença Metabólica, Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, Porto Alegre, RS, Brazil.

Hormone deficiency following ovariectomy causes activation of Na(+),K(+)-ATPase and acetylcholinesterase (AChE) that has been related to cognitive deficits in experimental animals. Considering that physical exercise presents neuroprotector effects, we decide to investigate whether exercise training would affect enzyme activation in hippocampus and cerebral cortex, as well as adenosine nucleotide hydrolysis in synaptosomes from cerebral cortex of ovariectomized rats. Female adult Wistar rats were assigned to one of the following groups: sham (submitted to surgery without removal of the ovaries), exercise, ovariectomized (Ovx) and Ovx plus exercise. Thirty days after surgery, animals were submitted to one month of exercise training, three times per week. After, rats were euthanized, blood serum was collected and hippocampus and cerebral cortex were dissected. Data demonstrated that exercise reversed the activation of Na(+),K(+)-ATPase and AChE activities both in hippocampus and cerebral cortex of ovariectomized rats. Ovariectomy decreased AMP hydrolysis in cerebral cortex and did not alter adenine nucleotides hydrolysis in blood serum. Exercise per se decreased ADP and AMP hydrolysis in cerebral cortex. On the other hand, AMP hydrolysis in blood serum was increased by exercise in ovariectomized adult rats. Present data support that physical exercise might have beneficial effects and constitute a therapeutic alternative to hormone replacement therapy for estrogen deprivation.
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http://dx.doi.org/10.1016/j.brainres.2009.09.013DOI Listing
December 2009

Ovariectomy impairs spatial memory: prevention and reversal by a soy isoflavone diet.

Metab Brain Dis 2008 Sep 22;23(3):243-53. Epub 2008 Jul 22.

Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcellos, 2600-Anexo, CEP 90035-003, Porto Alegre, Rio Grande do Sul, Brazil.

Since a previous study has shown that ovariectomy impairs spatial memory, we, herein, investigate the influence of pre- and post-treatment with a soy diet on the effects elicited by ovariectomy on spatial memory. In the pre-treatment, 20-day-old female Wistar rats were first fed for 60 days on a standard diet with casein (control) or a soy diet. At 80 days of age, the animals were assigned to one of the following groups: sham (submitted to surgery without removal of ovaries) and ovariectomized. One week after surgery, the rats were submitted to behavioral testing. In the post-treatment, 80-day-old female rats were assigned to one of the following groups: sham and ovariectomized. One week after surgery, animals were fed for 30 days with the same diet described above. Then, rats were submitted to water maze testing. Pre-treatment for two months before ovariectomy with the soy diet effectively prevented the increase in latency in finding the platform on the fifth day of training in the ovariectomized group. Ovariectomized rats subjected to soy diet post-treatment reversed the increase in latency to find the platform in the ovariectomized group on the fifth day of training and, the decrease in the time spent in target quadrant, the increase in the time spent in opposite quadrant and the latency to cross the platform location. Results show that both pre- and post-treatment protected against the impairment of memory, caused by ovariectomy. Post-treatment reversed various parameters of memory reference, indicating that post-treatment was more efficient than pre-treatment. Based on these findings, we suggest that soy diet (rich in isoflavones) may represent a novel therapeutic strategy to prevent or to treat cognitive symptoms found in some menopausal women.
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http://dx.doi.org/10.1007/s11011-008-9093-6DOI Listing
September 2008

Intrastriatal injection of hypoxanthine impairs memory formation of step-down inhibitory avoidance task in rats.

Pharmacol Biochem Behav 2008 Oct;90(4):594-7

Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.

The aim of this study was to investigate the effects of intrastriatal injection of hypoxanthine, the major compound accumulated in Lesch-Nyhan disease, on performance step-down inhibitory avoidance task in the rat. Male adult Wistar rats were divided in two groups: (1) saline-injected and (2) hypoxanthine-injected group. Treated-group received intrastriatal hypoxanthine solution 30 min before training session (memory acquisition) or immediately after training session (memory consolidation) or 30 before test session (memory retrieval) on step-down inhibitory avoidance task. Results show that hypoxanthine administration caused significant memory impairment in all periods tested. These results show that intrastriatal hypoxanthine administration provoked memory process impairment of step-down inhibitory avoidance task, an effect that might be related to the cognitive memory alterations in Lesch-Nyhan patients.
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http://dx.doi.org/10.1016/j.pbb.2008.05.001DOI Listing
October 2008