Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2390

O Doutorado Acadêmico pertence ao Programa de Pós-Graduação em Neurociências e Biologia Celular (PPGNBC) do Instituto de Ciências Biológicas (ICB) da Universidade Federal do Pará (UFPA).

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Acesso aberto (Open Access)
Ajustes motores compensatórios após lesão isquêmica focal unilateral do trato corticoespinhal
(Universidade Federal do Pará, 2017-06-30) CARVALHO, Walther Augusto de; BAHIA, Carlomagno Pacheco; http://lattes.cnpq.br/0910507988777644; PEREIRA JÚNIOR, Antônio; http://lattes.cnpq.br/1402289786010170
The aim of this work was to develop a new model of spinal cord injury caused by focal and unilateral transient ischemia after ET-1 microinjection in the dorsal funiculus and to evaluate the sensorimotor alterations of the anterior paw of rats (Wistar). Fifty (n = 50) animals (CEPAE / UFPA protocol BIO007912), who were trained, thirty-three (n = 33) were selected to compose control (n = 15), sham (n = 6) and injury (n = 12) groups. By using a micropipette, we injected the volume of 250 nL of saline (sham) or endothelin-1 (lesion) near the medial dorsal artery of the cervical segment C4 at a depth of 1 mm from the pial surface of the spinal cord. ET-1 induced cystic cavity formation of 0.421 mm2 (± 0.035 mm2, n = 3) on the corticospinal tract and suprajacent white matter, ipsilateral to the microinjection site that can be measured in cross-sections (50 μm) stained by the Nissl technique. The motor functions of the forepaw were evaluated by specific sensorimotor tests before and after injury at 3, 7 and 14 days. The results were evaluated by the ANOVA statistical test with Tukey post-hoc analysis (α = 0.05). Our results show in pasta test that after injury there is a compensatory motor behavior in which the non-preferential forepaw assumes the functions of the preferential forepaw. The Staircase test revealed a decrease in the ability to grasp the object with the preferred paw and the Contact test showed a decrease in sensitivity of the preferred paw.
Acesso aberto (Open Access)
Ajustes posturais antecipatórios e compensatórios em idosos com e sem lombalgia
(Universidade Federal do Pará, 2021-03) GARCEZ, Daniela Rosa; CALLEGARI, Bianca; http://lattes.cnpq.br/0881363487176703; https://orcid.org/0000-0001-9151-3896; YAMADA, Elizabeth Sumi; http://lattes.cnpq.br/7240314827308306
Chronic low back pain (DLC) is associated with changes in postural control and is highly prevalent in the elderly. Research shows that aging and DLC are described as important factors that affect postural control. The postural control impairments increase the risk of falls. Researches evaluating the postural control in elderly people with DLC are still necessary for greater effectiveness in balance rehabilitation programs to prevention falls in this population. The objective of this study is to verify whether anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are affected by DLC in elderly people by assessing their postural control during a self-initiated perturbation paradigm induced by rapid upper arm movement when pointing to a target. Elderly people were divided into: Group with DLC (GDLC) (n = 15) and Control Group (CG) (n = 15). The participants’ lower limb muscle onset and center of pressure (COP) displacements were assessed prior to perturbation and throughout the entire movement. T0 moment (i.e., the beginning of the movement) was defined as the anterior deltoid (DEL) onset, and all parameters were calculated with respect to it. The rectus femoris (RT), semitendinosus (ST), and soleous (SOL) showed delayed onset in the GDLC group compared with the control group: RF (control: -0.094 ± 0.017 s; GDLC: -0.026 ± 0.012 s, t = 12, p < 0.0001); ST (control: - 0.093 ± 0.013 s; GDL: -0.018 ± 0.019 s, t = 12, p < 0.0001); and SOL (control: -0.086± 0.018 s; GDL: -0.029 ± 0.015 s, t = 8.98, p < 0.0001). In addition, COP displacement was delayed in the GDLC group (control: -0.035 ± 0.021 s; GDL: -0.015 ± 0.009 s, t = 3; p = 0.003) and presented a smaller amplitude during APA COPAPA [control: 0.444 cm (0.187; 0.648); GDLC: 0.228 cm (0.096; 0.310), U = 53, p = 0.012]. The GDLC group required a longer time to reach the maximum displacement after the perturbation (control: 0.211 ± 0.047 s; GDLC 0.296 ± 0.078 s, t = 3.582, p = 0.0013). This indicates that GDLC elderly patients have impairments to recover their postural control and less efficient anticipatory adjustments during the compensatory phase. Our results suggest that people with GDL have altered feedforward hip and ankle muscle control, as shown from the SOL, ST, and RT muscle onset. This study is the first study in the field of aging that investigates the postural adjustments of an elderly population with GDLC. Clinical assessment of this population should consider postural stability as part of a rehabilitation program.
Acesso aberto (Open Access)
Alteração diferencial nos astrócitos radiais do hipocampo e neurogênese em aves marinhas com rotas migratórias constantes
(Universidade Federal do Pará, 2019-08-17) LIMA, Camila Mendes de; MAGALHÃES, Nara Gyzely de Morais; http://lattes.cnpq.br/2519507561210918; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286; https://orcid.org/0000-0001-6611-6880
Little is known about environmental influences on radial glia–like α cells (radial astrocytes) and their relation to neurogenesis. Because radial glia is involved in adult neurogenesis and astrogenesis, we investigated this association in two migratory shorebird species that complete their autumnal migration using contrasting strategies. Before their flights to South America, the birds stop over at the Bay of Fundy in Canada. From there, the semipalmated sandpiper (Calidris pusilla) crosses the Atlantic Ocean in a non-stop 5-day flight, whereas the semipalmated plover (Charadrius semipalmatus) flies primarily overland with stopovers for rest and feeding. Using hierarchical cluster and discriminant analysis of morphometric features to classify three-dimensionally (3D) reconstructed cells, we identified two morphotypes of radial glia, designated as Type I and Type II. The migratory process affected these cells differentially, with more intense morphological changes in Type I than in Type II morphotypes in both species. We also compared the number of doublecortin (DCX)-immunolabeled neurons with morphometric features of radial glial–like α cells in the hippocampal V region between C. pusilla and C. semipalmatus before and after autumn migration. Compared with migrating birds, the convex hull surface of radial glial–like α cells of wintering birds significantly increased in both C. semipalmatus and C. pusilla. This increase correlated with an increase of the total number of DCX-immunolabeled neurons in wintering birds. The decreased radial astrocyte morphological complexity in the semipalmated sandpiper and its increase in the semipalmated plover, a species that probably relies more on visuospatial information for navigation, may be significant, despite phylogenetic and other differences between these taxa. The migratory flight of the semipalmated plover, with stopovers for feeding and rest, versus the non-stop flight of the semipalmated sandpiper may differentially affect radial astrocyte morphology and neurogenesis.
Acesso aberto (Open Access)
Alterações oxidativas e inflamatórias induzidas pela dapsona no sangue e no córtex pré-frontal de camundongos: efeitos do ácido alfa-lipóico
(Universidade Federal do Pará, 2018-12-14) GOMES, Bruno Alexandre Quadros; MONTEIRO, Marta Chagas; http://lattes.cnpq.br/6710783324317390
Dapsone (DDS), a drug used in leprosy multidrug therapy, can cause many adverse reactions and intoxications, inducing the generation of reactive oxygen species (ROS) and imbalance in the redox state, increase methemoglobin (MetHb) formation, hemolysis and release of heme and iron free, which may interfere with redox homeostasis in more vulnerable regions, such as prefrontal cortex (PFC), causing neurotoxicity and even neuroinflammation. In this sense, antioxidant compounds with chelating properties such as α-lipoic acid (ALA) may play a key role in combating or preventing these alterations. Thus, this work aims to evaluate the effect of DDS on MetHb formation, peripheral oxidative stress, and oxidative changes and neuroinflammation in PFC, as well as, effects of ALA. For this, was induced MetHb formation in Swiss mice with DDS 40mg/kg ip for 5 days. Two hours after DDS administration, ALA was given at two concentrations (12.5 and 25 mg/kg). Besides MetHb percentage, total equivalent antioxidant capacity (TEAC), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) thiobarbituric acid reactive substances (TBARS), and iron concentrations in blood and PFC were evaluated, as well as, IL-1β, IL-17, and IL-4 cytokine concentrations, and de F4/80+, GFAP, and BDNF expression in PFC. Our results show that DDS induces the MetHb formation in red blood cells of mice, however, ALA was able to prevent or reverse the oxidation of hemoglobin induced by DDS at two used concentrationns. DDS reduced antioxidant capacity (TEAC) in plasma and red blood cells; decreased erythrocyte GSH, CAT, and SOD; and increased TBARS and plasma iron; however, ALA at two concentrations increased or reestablished TEAC in plasma and red blood cells at baseline levels. In addition to increasing or reestablishing GSH levels, SOD, and CAT in red blood cells, and decreased TBARS and iron levels, mainly in euthanized animals 4h after treatment. Curiously ALA 50mg/kg increased plasma iron concentrations. The treatment with DDS 40mg/kg also reduced TEAC, GSH, SOD e CAT in the PFC of the mice and increased TBARS and iron, characterizing oxidative stress, mainly in euthanized animals in 24h after treatment. Treatment with ALA increased or restored TEAC and GSH; and increased SOD and CAT in 12,5mg/kg concentration in euthanized animals 4h after treatment, as well as reducing TBARS levels and decreasing or preventing iron overload, mainly in euthanized animals 24h after treatment. DDS also promoting microglial and astrocyte activation in PFC, through F4/80+ e GFAP expression., with increased IL-1β and IL-4 production, and BDNF reduction, on the other hand, ALA 25mg/kg reduced GFAP and IL-1β expression, besides increased BDNF, suggesting that DDS also can cause neuroinflammation, and ALA presents antioxidant and anti-inflammatory properties against toxicity caused by DDS. These results suggest that ALA is promising and plays an important role in the prevention and/or formation of MetHb, reestablishment of redox balance and iron concentrations in both blood and PFC. Thus, ALA may be a usefull adjuvant therapy in DDS-induced toxicity, with lower toxicity and increasing adherence to treatment of leprosy patients.
Acesso aberto (Open Access)
Análise do efeito tóxico e alterações transcriptomicas de células neuronais e gliais após exposição ao fluoreto
(Universidade Federal do Pará, 2019-05-23) GOMES, Bruna Puty Silva; OLIVEIRA, Edivaldo Herculano Corrêa de; http://lattes.cnpq.br/0094007714707651; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468
Despite being widely used in dentistry for dental carie control, in high amounts fluoride may be associated with side effects of which the best known is dental fluorosis. In addition, studies suggest that even at low concentrations fluoride may exerts toxicity leading to damage on CNS. Functional toxicogenomics analysis of gene profile after exposure to contaminants has been used as a tool for the identification of biomarkers of exposure, as well as for the identification of signaling pathways that may be used for treatment and / or prevention of damage caused by the toxicity of certain compounds. As the molecular mechanism of fluoride toxicity still unknow, analysis of F chronic exposure on gene expression profile of CNS cells are necessary. Here we aimed to show the effect of fluoride exposure of plasma concentration founded on population that used to be exposed to fluoridated drink water, on the main CNS cells. In this way, we have used human cell lineage IMR-32 (neurons) and U87 (glial cells) to analyze parameter of viability, morphology and cell metabolism, ATP-synthesis, oxidative stress, DNA damage and global gene expression profile after 10 days exposure. Our results have shown that fluoride does not induce changes in IMR-32 cells. On the other hand, it induces cell death by necrosis, increased metabolism, decrease in ATP and GSH / GSSG in U87 cells and DNA fragmentation. The U87 gene expression profile is differentially altered after fluoride exposure, decreasing 1735 genes and an increasing expression of 1047 genes after exposure to 0.095μg / mL and decreasing of 1863 gene expression and increasing of 1023 expression after exposure to 0.22μg / mL. We also highlighted the major molecular pathways altered after exposure, such as the signaling pathway TNF-alpha via NFK-B and mitochondrial process. We also showed genes with significant importance biology (hub genes) such as the genes PTGES3, EP300, CYP1B1, RPS27A. Our results suggests that glial cell are affected by fluorides exposure and mitochondria has a major role on the mechanism of fluoride toxicity.
Acesso aberto (Open Access)
Atividade antineoplásica da 1-desoxinojimiricina em modelos de câncer in vitro
(Universidade Federal do Pará, 2021-12) FONSECA, Suzanne Suely Santos da; PEREIRA JÚNIOR, Antônio; http://lattes.cnpq.br/1402289786010170; https://orcid.org/0000-0002-0808-1058
Cancer is one of the diseases that kill the most in Brazil, with alarming projections until 2030. In view of the problems related to cancer treatment, such as the compromise of healthy cells and, consequently, the presence of adverse effects, it is imperative to seek of alternative substances that may have antineoplastic effects and that are effective in the treatment of patients with this disease. In this way, the use of bioactive compounds has been widely used in the fight against neoplasms. Thus, the substance 1-deoxynojimyricin (1-DNJ) isolated from Bagassa guianensis may have great anticancer potential. In view of the problems related to cancer treatment, such as the impairment of healthy cells and, consequently adverse effects, it is necessary to search alternative substances that may have antineoplastic effects and they are effective in the treatment of patients with this disease. The objective of this study was to evaluate the effect of 1-deoxynojirimycin (1-DNJ) extracted from wood residue of the species Bagassa guianensis in different cancer cell lines to investigate possible antineoplastic actions in vitro using gastric adenocarcinoma and glioblastoma cancer cell lines. To do that, it was evaluated the effect of the substance 1-deoxynojirimycin on cell viability in vitro after 72h of treatment in cell lines ACP02 and A172. We also evaluated the effect of this bioactive compound on cell migration pattern, cell death by apoptosis and cell cycle changes using flow cytometry and reactive oxygen production. The results showed that 1-deoxynojirimycin makes a significant reduction in cell viability of cancer cell cultures in both glioblastoma (A172) and gastric cancer cell (ACP02) cell lines. The reduction in viability appears to be more effective in glioblastoma cell lines, with a common ic50 much lower when compared to other cell lines. We propose that the reduction in viability may be related to the decrease in reactive oxygen production in both lines after treatment with 1-DNJ. Besides that, 1-DNJ interrupts the cell cycle, prevents cell migration and induces necrosis-like cell death in the ACP02 lineage and apoptosis in the A172 lineage. Therefore, we suggest that 1-deoxynojirimycin may be an important and effective chemopreventive substance for the treatment of glioblastoma and gastric adenocarcinoma cancers.
Acesso aberto (Open Access)
Atividade neuroprotetora do treinamento físico moderado contra os danos morfofuncionais cerebelares causados pelo consumo de etanol de forma intensa e episódica (Binge drinking) em ratos
(Universidade Federal do Pará, 2019-09) VIEIRA, Kátia Lamarão; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468; https://orcid.org/0000-0003-1486-4013
Ethanol (EtOH) is a psychotropic drug, central nervous system (CNS) depressant, but widely encouraged and consumed by Brazilian society, as well as in much of the world, reflecting on a public health problem. In recent decades, teenagers have been practicing a very common practice, which is binge drinking. The harmful consumption of EtOH promotes, besides biopsychosocial alteration, the homeostatic imbalance that causes neurodegeneration and loss of function with motor disorders. In contrast, the practice of moderate physical training (MPT) has been recommended for the maintenance of physical and mental health, as well as prevention or minimization of the development of some diseases due to motor activity inducing plastic and dynamic changes in the CNS, in order to favor the neurogenesis, synaptogenesis and angiogenesis, besides contributing to the synaptic modulation. In view of the benefits of MPT, it was investigated the neuroprotective effects on motor, tissue and biochemical parameters in the cerebellum of rats exposed to binge-pattern EtOH from adolescence to adulthood. Forty male Wistar rats with 30 days old were used and divided into four groups, the control being sedentary animals and treated with distilled H2O; the trained, composed of animals exercised and treated with distilled H2O; EtOH, formed by sedentary animals and treated with doses of 3 g/kg/day EtOH, 20% (w/v); and Trained + EtOH, with exercised animals and treated with doses of 3 g/kg/day EtOH, 20% (w/v). The MPT protocol was performed on a rodent treadmill for 5 days for 4 weeks and binge-pattern EtOH doses were administered by intragastric gavage in the same weeks as the MPT. After this period, the animals were submitted to open field and beam walking behavioral tests. Then, they were euthanized for cerebellum collection, evaluating immunohistochemistry from the levels of trolox equivalent antioxidant capacity (TEAC), reduced glutathione (GSH), nitrite and lipid peroxidation (LPO); as well as Purkinje cell morphology (PC), the fraction of anti-synaptophysine (SYP) and anti-myelin basic protein (MBP) immunolabeled area. According to the result, EtOH caused severe oxidative stress and motor damage, but the execution of the MPT performed promoted neuroprotective effects in the rat cerebellum, among them, the modulation of oxidative biochemistry by the restoration of GSH levels. decreased LPO levels and increased TEAC, as well as preventing neuronal loss, synaptic vesicle damage (SYP) and myelin components (MBP). Therefore, MPT can be considered as a significant therapeutic strategy for the acquisition of redox homeostasis, avoiding oxidative biochemistry imbalance, as well as tissue and functional damage in the cerebellum of rats treated by binge pattern EtOH.
Acesso aberto (Open Access)
Avaliação do óleo essencial de pau-rosa (Aniba rosaeodora Ducke) em modelo de depressão induzida por álcool em ratas adolescentes
(Universidade Federal do Pará, 2023-08) SANTOS, Éverton Renan Quaresma dos; MAIA, José Guilherme Soares; http://lattes.cnpq.br/1034534634988402; MAIA, Cristiane do Socorro Ferraz; http://lattes.cnpq.br/4835820645258101
Depression is a prevalent disorder worldwide, which affects the functionality and quality of life of the people. The linalool-rich rosewood essential oil (Aniba rosaeodora Ducke) displays activities on the central nervous system (CNS), including of antidepressant-type. The work aimed to evaluate the effect of the essential oil in adolescent female rats through a model of binge drinking-induced depression. The essential oil was extracted by hydrodistillation and analyzed by a dual system of gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (CG-FID). The in vitro antioxidant capacity of the essential oil was determined in the 1,1-diphenyl-2-picrylhydrazyl (DPPH•) radical scavenging assay. Female Wistar rats, 29 days old, received distilled water or ethanol (3 g/kg/day) orally in 4 binge episodes, and saline solution or rosewood oil (35 mg/kg) intranasally once a day for 28 days. After the experimental treatment, splash and forced swimming tests were performed. The brain-derived neurotrophic factor (BDNF) and S100B gene expression, biological parameters of the oxidative stress and levels of pro-inflammatory cytokines were determined in the prefrontal cortex and hippocampus. The OEPR+EtOH group increased self-cleaning time and decreased immobility time, both significantly compared to the EtOH group in the splash and forced swimming tests, respectively. The essential oil behavioral effects were related to positive modulation of BDNF and S100B genes, to restoration of glutathione (GSH) and Trolox equivalent antioxidant capacity (TEAC) levels, in addition to the attenuation of the increase of thiobarbituric acid reactive species (TBARS), Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) induced by alcohol. The results suggest that essential oil improved the alcohol-induced depressive profile through a neuroprotective mechanism by positively modulating the gene expression of neurotrophic factors, rebalancing the antioxidant status and attenuating the inflammatory process, possibly due to the linalool action.
Acesso aberto (Open Access)
Desenvolvimento de aplicativo para realização do finger tapping test e a influência do sexo e da dominância manual no desempenho do finger tapping test baseado em smartphone
(Universidade Federal do Pará, 2023-11) BRITO, Felipe André da Costa; SOUZA, Givago da Silva; http://lattes.cnpq.br/5705421011644718; https://orcid.org/0000-0002-4525-3971
The Finger Tapping Test (FTT) is a classical neuropsychological test that assesses motor functioning, and recently it has been employed using smartphones. For classical protocols, it has been observed that sex and handedness influence the performance during the test. By assessing the influence of sex and handedness on the test, it is possible to adjust the performance measurements to ensure the validity of test results and avoid sex- and handedness-related bias. The present study aimed to evaluate the influence of sex and handedness on smartphone-based FTT performance. We developed an Android application for the FTT and recruited 40 males and 40 females to carry out three spatial designs on it (protocols I, II, and III). Participants’ performance was measured using the global, temporal, and spatial parameters of the FTT. We observed that for the performance in protocol I, handedness had a significant influence on global and temporal variables, while the interaction between handedness and sex had a greater influence on spatial variables. For protocols II and III, we observed that handedness had a significant influence on global, temporal, and spatial variables compared to the other factors. We concluded that the smartphone-based test is partly influenced by handedness and sex, and these factors should be considered during the evaluation of the smartphone-based FTT.
Acesso aberto (Open Access)
Efeito da competência leitora nas estratégias de organização perceptual da cena visual em escolares
(Universidade Federal do Pará, 2023-02) RESQUE, Deusa Priscila da Silva; MATOS, Felipe de Oliveira; http://lattes.cnpq.br/4207066833785568; https://orcid.org/0000-0002-4926-4694; PEREIRA JUNIOR, Antonio; http://lattes.cnpq.br/1402289786010170; https://orcid.org/0000-0002-0808-1058
The current Brazilian educational scenario, evaluated by different national and international indicators, has shown alarming results in mathematics, science and especially in reading. The country is in the last positions in all evaluations. For the change of this scenario, urgent educational measures that respect the student's biological and social development are necessary. The applied neurosciences to education emerge as a theoretical model of aid for pedagogical practices that aim to improve quality in education. An important contribution of neurosciences in education is focused on reading, through a theoretical/practical contribution on brain functioning those points more effective paths for literacy with a view to reading competence. In this sense, it was possible to understand that the human species has not yet developed a specific neural system for reading, using other brain structures for this function, ie literacy depends on a neural recycling process of brain structures associated with Sensory, motor and language functions, as is the case with brain regions associated with faces recognition, to accommodate the decoding of the written word. The aim of this study is to investigate reading in school -age children. To this end, the present thesis divided into two studies: Study 1 that investigates the inhibition of the generalization of letters in mirror in school -age children and the study 2 that investigates the relationship between reading competence and perceptual organization strategies of the visual scene in schools . Both studies were conducted in three public schools in the Belém do Pará Metropolitan Region, Brazil. Altogether two hundred and thirty -one subjects aged 6 to 10 years (113 boys, 8.2 ± 1.4 years and 118 girls, 8.2 ± 1.4 years), enrolled 1 to 5th years, were recruited, 1,2 ± 1.4 years old) elementary School. Among these eighty -eight subjects were students from school 1, fifty -two from school 2 and ninety from the school 3. In all, six tests were applied, each school participated in a different group of tests. Our results show that the performance of boys in the 6-10 year old is different from that of girls in the same age group for the reading competence test, with boys with higher performance, although it is not possible to establish differences between genders to the perceptual closure test. What's more, while boys performed significantly better in the rotation of letters in the older group, girls' performance was similar in both groups. This pattern is reverse for the mirror's task, with the older girls surpassing their younger counterparts and the boys performing similarly in both groups. Since the age period of our sample is not associated with large variations in reproductive steroid levels, we propose that the similarity of performance between younger and older girls in the mental rotation of letters may be associated with society's traditional attitudes and expectations and expectations about the relationship between spatial visual skills and gender. As for the mirror's task, while only girls showed a significant difference between the two age groups, the boys showed improvement, as expected by the mirror generalization inhibition to letters during reading. These findings are relevant to the development of more effective future strategies for optimizing the literacy process of school -age children, combining education and neuroscience. For this, more studies must be performed and the number of subjects investigated should be expanded.
Acesso aberto (Open Access)
O efeito do ruído espacial de cor sobre a discriminação limiar de luminância: investigação básica e aplicada em populações expostas ao mercúrio
(Universidade Federal do Pará, 2018-05-22) FARIAS, Letícia Miquilini de Arruda; CÔRTES, Maria Izabel Tentes; http://lattes.cnpq.br/3913689546568227; SOUZA, Givago da Silva; http://lattes.cnpq.br/5705421011644718
Natural images are a complex set of color and luminance contrast that when combined in visual scene helps to create the discrimination of objects from the surrounding visual environment. A series of neural streams transmits the color and luminance information from the retina to the higher cortical centers. Several proposals have been made to study how the visual system processes the stimuli that combining color and luminance contrasts. This thesis has as main proposal to introduce a new stimulus to be used luminance discrimination task under chromatic noise masking. Thus, five experiments were carried out with focus this new paradigm to explore basic and applied questions about its use. Study 1 investigated the effect of color noise saturation on the threshold discrimination of luminance contrast. Study 2 investigated how the mosaic arrangement contributed to the contrast values of luminance contrast thresholds under the chromatic noise masking. Study 3 investigated the influence of the color content of the noise on the threshold discrimination of the luminance contrast. Study 4 investigated the influence of the polarity of the luminance contrast under the chromatic noise masking on the estimated threshold contrasts. Study 5 compared the values of threshold luminance contrasts under chromatic noise masking of two riverine populations of different Amazonian regions of the Pará State and exposed to different levels of mercury by feeding. The main finding of this thesis was that the luminance contrast thresholds varied as a function of the vector length of the chromatic noise values. The higher chromatic noise length, the higher luminance contrast threshold. The contrast threshold estimated by the non-mosaic stimulus exhibited significantly lower values than those estimated with mosaic stimuli (p <0.01). No statistical difference was observed between the contrasts threshold estimated around the five reference chromaticities at different saturation conditions (p> 0.05). The luminance contrasts thresholds estimated in the luminance decrement protocol were xiii significantly lower at all saturation levels than those estimated using the luminance increase protocol (p <0.05). There is no statistical difference between the thresholds of estimated luminance discrimination among riverine communities that were differently exposed to mercury (p> 0.05). The luminance contrasts threshold estimated by the new stimulus, described in this thesis, were influenced by chromatic and spatial noise, and by the polarity of the stimulus of luminance contrast. However, the different chromatic noise compositions did not exhibit any influence on the luminance discrimination. The presence of one or more color-sensitive visual pathways and luminance may be the physiological substrate of the mechanism underlying the luminance contrast perception of this new stimulus.
Acesso aberto (Open Access)
Efeitos anti-inflamatórios e neuroprotetores do extrato de gergelim preto (Sesamum indicum L.) em um modelo experimental de isquemia estrial
(Universidade Federal do Pará, 2024-03) SANTOS, Ijair Rogério Costa dos; LEAL, Walace Gomes; http://lattes.cnpq.br/2085871005197072
Acidente Vascular Encefálico (AVE) é uma neuropatologia caracterizada como o surgimento súbito global ou focal de déficits da função neurológica de duração superior a 24 horas ou que leve a morte, cuja única causa reside na origem vascular. Estudos sobre a incidência, comprometimento físico e mortalidade enquadram o AVE como a segunda causa de morte no mundo e a principal complicação orgânica que leva às disfunções físico-neurológicas, frequentemente, graves e permanentes. A indução do AVE em animais de experimentação e o entendimento de sua fisiopatologia, bem como a busca de tratamentos que minimizem os danos neurológicos e estimulem a recuperação morfofuncional do indivíduo afetado são temas de grande relevância científica e clínica. Neste estudo, investigamos os possíveis efeitos neuroprotetores e/ou anti-inflamatórios do extrato supercrítico de gergelim preto (Sesamun indicum L.) após lesão isquêmica focal por microinjeções de 80 pmol de endotelina-1 no estriado de ratos adultos, usando as coordenadasestereotáxicas: 1,2 mm, anterior-posterior; 2,5 mm, médio-lateral; 4,0 mm, dorsoventral. Após a indução do AVE, os grupos controles foram tratados com tween a 5% e os tratados receberam 150 mg/kg de gergelim, ambos, por via intraperitoneal, em duas doses diárias de 75 mg/kg. A neuropatologia foi obtida em secções encefálicas com 50 e 20 μm de espessuras e coradas com violeta de cresila, para identificar a área de lesão, e/ou imunomarcadas por anticorpos específicos à identificação de neurônios (anti-NeuN), astrócitos (anti-GFAP) e micróglia (anti-ED1). Secções de 5 μm de espessura de rim e fígado corados por métodos histológicos e histoquímicos não mostraram alterações morfológicas nas células que compõem esses órgãos essenciais, sugerindo baixa toxicidade do extrato. Todas as secções coradas e/ou imunomarcadas foram visualizadas em microscópio óptico e seuscampos mais ilustrativos, em todos os tempos de sobrevida e grupos experimentais,foram capturados digitalmente e editados em computador. A quantificação das célulasNeuN+(neurônios), micróglia/macrófagos (ED1+) e astrócitos (GFAP+) na área de lesão, três secções por lâmina, todo campo ao redor de lesão por secção, com auxílio de uma gradícula de área 0,0625 mm2 na ocular possibilitou o teste t-Student à análise estatística entre os grupos e o uso do programa Microsoft Excel à plotagem dos gráficos. Por fim, uma caracterização da citotoxicidade in vitro, bem como a verificação do índice de acidez do extrato revelou baixa acidez e mínima agressividade em células sanguíneas, que ratifica o uso do extrato supercrítico em estudos que visem otratamento de doenças agudas e crônicas no SNC.
Acesso aberto (Open Access)
Efeitos da suplementação com açaí clarificado (Euterpe oleracea Mart.) sobre marcadores de estresse oxidativo em pacientes com doença renal crônica em hemodiálise
(Universidade Federal do Pará, 2019-06) MARTINS, Isabelle Christine Vieira da Silva; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978; https://orcid.org/0000-0003-3647-9124
Acesso aberto (Open Access)
Efeitos do exercício físico sore parâmetros cognitivos e bioquímicos em ratos expostos ao etanol de forma intensa e episódica (Binge Drinking)
(Universidade Federal do Pará, 2018-12-21) TEMBRA, Dinair Pamplona dos Santos; LIMA, Rafael Rodrigues; http://lattes.cnpq.br/3512648574555468
The consumption pattern of heavy and episodic ethanol, weekend consumption, characterizes the pattern of excessive alcohol consumption or binge drinking that promotes an imbalance of brain metabolic functions, contributing to neurodegeneration and cerebral dysfunction. And because it is a legal drug, it has global relevance in public and social health. In this way, we aimed to investigate the effects of physical training of moderate intensity, in treadmill, on the deleterious effects of ethanol on hippocampus functions related to memory and learning. For this, 80 Wistar rats were divided into four groups: Control group; Trained group (animals trained and treated with distilled water); Ethanol group (animals not trained and treated with doses of 3 g / kg / day of ethanol, 20% w / v); and ethanol + trained group (animals trained and exposed to ethanol). Physical exercise was performed on a treadmill for 5 days a week for 4 weeks and all doses of ethanol and distilled water were administered by intragastric gavage (three days a week) in four repeated cycles. After the experimental period, the animals were submitted to the task of object recognition and Morris aquatic labyrinth test, and after euthanasia, blood and hippocampus were collected to measure levels of antioxidant capacity equivalent to trolox (TEAC), content of reduced glutathione (GSH), nitrite and lipid peroxidation. (LPO). Our results showed that EtOH caused marked oxidative stress and mnemonic damage, and physical exercise promoted neuroprotective effects, including modulation of oxidative plasma biochemistry (by restoration of GSH levels) and hippocampus (reducing levels of LPO and increasing antioxidant parameters) and improving cognitive function. Therefore, physical exercise may be an important prophylactic and therapeutic tool to improve and even prevent the deleterious effects of ethanol on cognitive functions.
Acesso aberto (Open Access)
Em direção à costa brasileira fugindo do inverno: rotas migratórias contrastantes e plasticidade diferencial dos astrócitos hipocampais
(Universidade Federal do Pará, 2018-01-04) OLIVEIRA, Marcus Augusto de; DINIZ, Cristovam Wanderley Picanço; http://lattes.cnpq.br/2014918752636286
One of the largest seasonal events on the planet is the migration of birds from the Arctic to the southern hemisphere fleeing from winter and returning to the Arctic during the spring to the breeding season. Billions of individuals need to remember the routes learned during this epic journey and find the same places to rest and feeding. These birds can navigate thousands of miles with great accuracy, utilizing their spatial and temporal memories associated with the hippocampus, a key area for accomplishing this task. Recently, we have shown that the semipalmated sandpiper Calidris pusilla, after crossing the Atlantic towards the coast of South America, revealed significant changes in its hippocampal astrocytes. In fact, the hippocampal astrocytes of birds captured on the coast of Bragança in Brazil, compared with those of the hippocampus of individuals caught in the Bay of Fundy, Canada, were less numerous and exhibited shrunken branches. In the present work, we used another semipalmated shorebird, Charadrius semipalmatus, which, although having the same start and end points of C. pusilla migration, uses a different migratory strategy, performing a flight over the continent with stops for rest and feeding. Taking advantage of the opportunity offered by contrasting migratory flights, we tested the hypothesis that wintering bird species of the C. semipalmatus caught on the coast of Bragança (Brazil) would show greater morphological complexities than the hippocampal astrocytes of these migratory birds captured in the Bay of Fundy (Canada). Since the stands for food and rest, as well as the constant change in the landscape would constitute an enriched environment of multisensory stimuli, we expected to find in the individuals of C. semipalmatus captured in Bragança, an increase of the complexity, in opposition to the reduction in complexity previously found in C. pusilla. To test this hypothesis, we compared the three-dimensional (3-D) morphological characteristics of the adult C. semipalmatus astrocytes captured in the Bay of Fundy (n = 265 cells) with those of wintering birds captured in the coastal region of Bragança, Brazil, (n = 242 cells), and compared with the results obtained with C. pusilla. The Neurolucida program was used for three-dimensional reconstructions and the hierarchical cluster analysis (Ward’s method) was used to classify cells. This analysis showed two families of astrocytes, which we designated Type I and Type II, based on several morphological characteristics. Contrary to our expectations, Type I and Type II phenotypes showed, on average, independently of the species, lower morphological complexity after migration, and this reduction was significantly higher in Type I than in Type II. The magnitudes of these changes were significantly higher in C. pusilla than in C. semipalmatus. Taken together, these findings suggest that contrasting long-distance migratory flight strategies may differentially affect the astrocyte morphology and that distinct astrocyte morphologies may be associated with different functional roles during migration.
Acesso aberto (Open Access)
Estudo do desenvolvimento auditivo da habilidade de fusão binaural
(Universidade Federal do Pará, 2022-04) ARAÚJO, Francisca Canindé Rosário da Silva; SILVA FILHO, Manoel da; http://lattes.cnpq.br/2032152778116209
Introduction: Binaural Interaction (BI) allows the introduction of auditory information (in the brain as a function of differences in perception of intensity or time of acoustic stimuli). Allows you to assess the action and integrated co- operative of the brainstem in lower understanding. As the maturation of the central nervous system occurs in the craniocaudal direction, the response to this ability may change during the course of development. Objectives: To normalize and compare the development with increasing age of response in the binaural diffusion test (BPT) with digital low-pass (LP) and high-pass (HP) filters in normative listeners. Methods: Prospective, cross-sectional and observational study. A total of 120 years were evaluated, in different age groups (6 to 8 years old, 10 to 12 years old, 14 to 16 years old and 20 to 30 years old) with TFB, filter at Fc 500/1700 Hz digital Finite Impulse Response type order 4096, with null phase and 5000 between 18 and 30 years with unfiltered speech material. Results: a progressive improvement in performance with increasing age (ANOVA (one-way): p<0.0001). There was a significant difference between the filtered words, age and the unfiltered p < (Dunnet: any filtered words,01). The difference between the age groups was significant (Tukey: p<0.01), less for the results obtained in the age groups of 6-8 and 10-12 years and of 14-16 and 18- 30 years. Discussion: IB is a skill that evolves with age development and NC fabrication. Final considerations: The interpretation of the TFB should take into account the performance by age group of the patients. This is important for future applications of these tests in people with Auditory Processing Disorder.
Acesso aberto (Open Access)
Estudo eletrorretinográfico da adaptação à luz de vias de processamento específicas de cone e de oponência em cor e luminância
(Universidade Federal do Pará, 2017-12-15) COSTA, Alódia Brasil; SILVA, Anderson Manoel Herculano Oliveira da; http://lattes.cnpq.br/8407177208423247
Visual system has an essential function called light adaptation or photopic adaptation, which consists in the regulation of light sensitivity allowing visual adaptation to a wide range of illumination levels. This phenomenon is not fully elucidated. Therefore, the present study aims to evaluate the magnitude and temporal pattern of the variation of retinal electrical responses for L cone and M cone selective stimuli and for luminance pathway and red-green color pathway specific stimuli, making possible the evaluation of the red-green parvocellular (P pathway) and magnocellular (M pathway) visual pathways activity, during the photopic adaptation. For such purpose, 6 healthy subjects underwent 30 minutes of dark adaptation and then were exposed a light steady background for 16 min. The stimuli were given every 2 min and the electrical retinal response was recorded by full field electroretinogram (ffERG) over 16 min. The triple silent substitution method was used to isolate the responses of pathways originating from the L or M cone. We also used specific stimuli of luminance (Lum) and red-green color (Crom). For each stimulation type was used intermediate (12 Hz, which reflects the activity of the red-green parvocellular pathway - P pathway) and high (36 Hz, which reflects the activity of the magnocellular pathway - M pathway) temporal frequency, resulting in 8 stimulation conditions. Amplitude and phase of the first (F), second (2F) and third (3F) harmonic components were extracted by Fast Fourier Transform. It was observed that amplitude and phase increased over light adaptation time with simple sine wave form in the most of components and stimulation conditions. The relative increases in F amplitude from the M-cone driven responses during the light adaptation were higher than those L-cone driven ERGs at both temporal frequencies, 12 Hz (M = 1.21, L = 0.33) and 36 Hz ( M = 1.94, L = 0.55), as well as they were higher at 36 Hz than at 12 Hz for the two cones. In general, there was slight F phase increase during the light adaptation time (<30 degrees), slightly higher at 36 Hz. Regarding the light adaptation kinetics, F amplitude and phase that seem reflect the activity of the P pathway presented a faster adaptation (L-cone 12 Hz, M-cone 12 Hz, Crom 12 Hz, Lum 12, with a mean of 1.4 min) and those that probably reflect activity of the M-pathway had slower adaptation (Lum 36 Hz, L-cone 36 Hz, M-cone 36 Hz, with a mean of 4.9 min). Thefore, M and P pathways presented different magnitude and kinetics of light adaptation, being the M pathway the pathway of greatest increase and slower adaptation.
Acesso aberto (Open Access)
Estudos de mecanismos cromáticos e acromáticos para o potencial cortical provocado visual (VECP) e multifocal (mfVEP)
(Universidade Federal do Pará, 2017-10-06) ARAÚJO, Carolina dos Santos; SOUZA, Givago da Silva; http://lattes.cnpq.br/5705421011644718
Visual evoked potentials (VECPs) and multifocal visual evoked potentials (mfVEPs) are being widely used to investigate cortical information processing in response to stimuli at different sites of the visual field and present the potential for complement information to conventional VEPs on chromatic and achromatic mechanisms of human vision. The objective of this work was to investigate the contribution of chromatic and achromatic mechanisms to VECP and mfVEP from two experiments: in the first, 9 healthy trichromates subjects with normal or corrected to 20/20 visual acuity were submitted to a visual stimulation of 8º of size, formed by achromatic sinusoidal gratings in 7 spatial frequencies (from 0.4 to 10 cpd) and in six contrast levels (from 3.12% to 99%); in the second, a multifocal dartboard with 60 sectors covering 40° of visual angle was shown for 14 healthy subjects (12 trichromates, 1 protan and 1 deutan discromatopsic type) in 7 different ratios of red-green luminance (R/R+G) and in one achromatic condition (99%). The two stimuli were presented as a reverse pattern, temporally controlled by m-sequences. The first slice (K2.1) and the second slice (K2.2) of the second order kernel were extracted. In experiment 1, were analyzed the main components of the waveforms recorded and in experiment 2 the signal-to-noise ratio (SNR) of the waveforms was analyzed to classify them as reliable (SNR> 1.35) or unreliable (SNR <1.35) and the number of reliable waveforms in 6 different rings with the same visual eccentricity (R1 being the central ring and R6 the most peripheral ring) was quantified. The results of experiment 1 indicated that responses in K2.1 were dominated by M pathway, and responses in K2.2 reflected the contribution of P pathway. The results of experiment 2 were similar for K2.1 and K2.2. In the R1-R4 rings, all red-green luminance ratios showed a similar number of reliable waveforms. In the R5-R6 rings, there are more reliable waveforms in the red-green luminance ratios with high luminance contrast, while the equiluminant condition has the fewest reliable responses. Protan and deutan subjects showed inverted results: stimulus conditions with green brighter than red generated more reliable waveforms in the protan subject (0.2-0.4), while the opposite combination generated more reliable waveforms in the deutan subject. The two second-order kernel slices are useful for studying the chromatic and achromatic mfVEP mechanisms. The results in R1-R4 indicated a similar contribution of chromatic and achromatic mechanisms for mfVEP, while R5-R6 show the most pronounced contribution of the achromatic mechanism to mfVEP. The method used allowed to identificate specific characteristics of protan and deutan discromatopsic type from obtained data. discromatopsic type from obtained data.
Acesso aberto (Open Access)
O extrato aquoso de Coriandrum sativum L. promove neuroproteção contra alterações motoras e danos oxidativos na progênie de ratas expostas ao metilmercúrio
(Universidade Federal do Pará, 2020-01) RODRIGUES, Keuri Eleutério; PRADO, Alejandro Ferraz do; http://lattes.cnpq.br/7016475842644161; NASCIMENTO, José Luiz Martins do; http://lattes.cnpq.br/7216249286784978; https://orcid.org/0000-0003-3647-9124
This study aimed to investigate the efects of Coriandrum sativum aqueous extract (EACS) on the rat progeny of mothers exposed to methylmercury (MeHg). The presence of bioactive compounds and EACS's antioxidant capacity been evaluated, and the spring were assessed for their total mercury levels, motor behavioral parameters and oxidative stress in the cerebellum. The analysis of the bioactive compounds revealed significant amounts of polyphenols, flavonoids, and anthocyanins, as well as a variety of minerals. A DPPH test showed the EACS had important antioxidant activity. The MeHg + EACS group performed significantly better spontaneous locomotor activity, palmar grip strength, balance, and motor coordination in behavioral tests compared the MeHg group, as well as in the parameters of oxidative stress, with similar results to those of the control group. The MeHg + EACS group alsohad significantly reduced mercury levels in comparison to the MeHg group. Based on the behavioral tests, which detected large locomotor, balance, and coordination improvements, as well as a reduction in oxidative stress, we conclude that EACS had positive functional results in the spring of rats exposed to MeHg.
Acesso aberto (Open Access)
Função de recuperação do nervo auditivo após doze meses de uso do implante coclear
(Universidade Federal do Pará, 2022-03) YAMAGUCHI, Cíntia Tizue; SILVA FILHO, Manoel da; http://lattes.cnpq.br/2032152778116209
Introduction: Cochlear implant is the standard treatment for severe and profound bilateral sensorineural hearing loss. To optimize the adaptation of this device, especially in patients who do not have the ability to refer to the parameters necessary for programming, such as children and people with associated disabilities, objective tests based on the action potential of auditory nerve fibers have been studied as possible predictors. of these parameters to be used in cochlear implant programming. The auditory nerve recovery function is a test that measures the time the auditory nerve needs to recover from a stimulus (leave the absolute refractory period) to receive new stimulation and possibly be more responsive to the auditory sensation offered by the cochlear implant. Objective: Through a specific software for cochlear implants, with the objective of measuring the time constant (τ) in the intraoperative period and in the postoperative period after 12 months of cochlear implant use in children. Method: We recruited children with cochlear implant and intraoperative neural response, evaluated the recovery function using commercially available cochlear implant software. Data were collected intraoperatively and repeated twice 12 months after surgery. Results: We found that the recovery time of the auditory nerve increases after 12 months of cochlear implant use. Our results also show that the profile of temporal responses is significantly higher in the postoperative measurement than in the intraoperative one. The test-retest reproducibility of the composite evoked action potential recordings proved to be reliable and stable. Conclusion: There was a change in 12 months of cochlear implant use, in relation to the same measure at the intraoperative moment in the subjects of this study. The intraoperative τ measurement was faster, however, in the postoperative period the mean showed higher τ values. However, the current level was different intraoperatively and 12 months after use, needing to be further explored. There was no statistical difference regarding the test-retest in the postoperative period, showing reliability and reproducibility of the measurement. Possibly it would be the beginning of the study of a responsiveness profile in relation to the recovery time of the auditory nerve.