Navegando por Palavras-chave "Electrophysiology"

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    Acuidade visual e eletrorretinografia de campo total em pacientes com síndrome de Usher
    (Conselho Brasileiro de Oftalmologia, 2005-04-01) Mendieta, Luana [UNIFESP]; Berezovsky, Adriana [UNIFESP]; Salomão, Solange Rios [UNIFESP]; Sacai, Paula Yuri [UNIFESP]; Pereira, Josenilson Martins [UNIFESP]; Fantini, Sérgio Costa [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    PURPOSE: Usher's syndrome (US) is a group of genetically distinct autossomal conditions, characterized by sensorineural hearing loss accompanied by a retinal dystrophy indistinguishable from retinitis pigmentosa (RP). The purpose of this study was to analyze full-field electroretinography (ERG) and visual acuity (VA) among patients with type I and II Usher's syndrome. METHODS: Electroretinography responses and visual acuity were studied in 22 patients (mean age at test = 26.8±16.8 years). Seventeen patients had SU type I and 5 patients were diagnosed as Usher's syndrome type II. RESULTS: Mean visual acuity was 0.9 logMAR (20/160, Snellen equivalent) for patients with Usher's syndrome type I and 0.4 logMAR (20/50, Snellen equivalent) for patients with Usher's syndrome type II. Scotopic rod and maximal responses were non-detectable in both groups. Mean amplitude for oscillatory potentials was 14.5 µV ±6.1 in Usher's syndrome type I and 12.6 µV±5.2 in Usher's syndrome type II. Cone responses were non-detectable in 95% of the patients with Usher's syndrome I and in 100% of patients with Usher's syndrome II. Mean amplitude for 30 Hz flicker photopic cone response was 3.1 µV±4.1 for Usher's syndrome type I and 1.0 µV±0.6 for type II with mean implicit time of 34.0 ms±6.2 (US I) and 35.8 ms±3.1 (type II). CONCLUSIONS: Visual acuity was relatively preserved in both groups, however Usher's syndrome II group showed better visual acuity results. Electroretinography findings were severely reduced in both groups, with most patients showing non-detectable rod and cone responses.
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    Acuidade visual e função de bastonetes em pacientes com retinose pigmentária
    (Conselho Brasileiro de Oftalmologia, 2004-10-01) Berezovsky, Adriana [UNIFESP]; Pereira, Josenilson Martins [UNIFESP]; Sacai, Paula Yuri [UNIFESP]; Fantini, Sérgio Costa [UNIFESP]; Salomão, Solange Rios [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    PURPOSE: To investigate visual acuity and rod function, and correlate them to different clinical parameters in patients with retinitis pigmentosa (RP). METHODS: A cohort of 199 patients with retinitis pigmentosa (110 males and 89 females), aged 6-79 years (mean = 36.8±17.5) had their monocular visual acuity measured by the ETDRS chart and rod function assessed by full-field electroretinogram and dark-adapted thresholds. The distribution of different genetic subtypes of retinitis pigmentosa was 20.3% autosomal dominant, 14.2% X - linked, 24.2% autosomal recessive and 41.3% isolated. History of consanguinity was found in 41 (20.6%) patients. Forty-one patients (20.6%) were 20 years old or less, 77 (38.6%) ranged from 21 - 40 years, 61 (30.7%) from 41 - 60 years, and 20 (10.1%) were 61 years or older. Peak-to-peak amplitude and b-wave implicit time were measured and statistically analyzed (one-way ANOVA). Pearson correlation was performed between rod amplitude and dark-adapted thereshold and rod amplitude and visual acuity. RESULTS: Analyzing the visual acuity data according to genetic subtypes, without considering age, showed that as a group, patients with autosomal recessive and isolated retinitis pigmentosa have less severe impairment of visual acuity, than those with X-linked retinitis pigmentosa. Nyctalopia begun earlier in X-linked groups, compared with the remaining groups (p=0.011). A negative correlation was found between dark-adapted thereshold and scotopic rod amplitude (Pearson correlation coefficient = - 0.772 and P =0.000). There were no significant relationships between visual acuity and rod response by electroretinogram (Pearson correlation coefficient = 0.0815 and P = 0.286), P > 0.050. CONCLUSIONS: In a cohort of retinitis pigmentosa patients, 31.2% had vision of 20/40 or better. Rod function loss was highly correlated when assessed electrophysiologically (ERG) and psychophysically (dark-adapted thershold). No correlation was found between rod response measured by electroretinogram and visual acuity.
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    Alterações encontradas no potencial visual evocado por padrão reverso em pacientes com esclerose múltipla definida
    (Conselho Brasileiro de Oftalmologia, 2007-12-01) Andrade, Eric Pinheiro De; Sacai, Paula Yuri [UNIFESP]; Berezovsky, Adriana [UNIFESP]; Salomão, Solange Rios [UNIFESP]; Universidade de Santo Amaro; Universidade Federal de São Paulo (UNIFESP)
    INTRODUCTION: Multiple sclerosis is an idiopathic demyelinating disease that may affect the optic nerve leading to acute unilateral visual loss, which could be observed by means of evoked visual potential (VEP). This exam is much valued for studying prechiasmatic visual paths in multiple sclerosis. PURPOSE: To analyze the findings of pattern reversal VEP in patients with prior diagnosis of multiple sclerosis and to compare them to visual acuity. METHODS: Twenty-four patients with a definite diagnosis of multiple sclerosis were submitted to pattern reversal VEP from October 2001 to March 2007. RESULTS: In P100 component response, at 15' and 1º stimuli, 19 eyes presented latency response up to 115 ms in both stimuli, which coincided in 6 eyes with latency response between 116 and 135 ms; 11 eyes had a latency response higher than 135 ms, and four eyes did not respond to stimuli. Correlating visual acuity with P100 latency for 15', in Pearson r correlation, r=0.85 with p=0.000000123, and for 1º, r = 0.87 with p=0.0000000338. CONCLUSION: Approximately 60.4% of patients presented abnormalities. However, the correlation between the P100 latency (15' and 1º) and visual acuity was statistically significant; therefore the better the visual acuity, the better the response to stimuli of the pattern-reversal VEP.
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    Análise eletrofisiológica do hipocampo durante o sono dessincronizado do rato
    (Universidade Federal de São Paulo (UNIFESP), 1995) Valle, Angela Cristina do [UNIFESP]; Iaria, Cesar Timo [UNIFESP]
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    Auditory Brainstem Response: reference-values for age
    (Sociedade Brasileira de Fonoaudiologia, 2014-04-01) Rosa, Luana Araujo Cruz; Suzuki, Marcia Rumi; Angrisani, Rosanna Giaffredo; Azevedo, Marisa Frasson de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
    PURPOSE:To study the absolute latencies of waves I , III and V and interpeak I-III , III-V and I-V of Auditory brainstem responses obtained in preterm newborns in relation to post-conceptual age, term newborns and six months of age infants, establishing reference values ​​for each age group.METHODS:Retrospective study realized through the analysis of tests performed on 80 infants divided into four groups, being the group one composed per newborns assessed between 35 and 36 weeks post-conceptual age; group two by newborns assessed between 37 and 38 weeks; group three with newborns reviewed between 39 to 40 weeks; and group four with infants evaluated with six months.RESULTS:The wave I absolute latency in the group one was 1.81 ms, decreasing to 1.79 ms in groups two and three, and to 1.70 ms in group four. The wave III latency in group one was 4.74 ms, decreasing to 4.62 ms in group two, to 4.56 ms in the group three and to 4.37 ms in the group four. The wave V latency in group one was 7.14 ms, in the group two it was 7.05 ms, in the group three 6.90 ms; and in the group four it was 6.50 ms. Interpeak latencies were also decreased in all groups.CONCLUSION:The latencies studied decreased with the increasing age and were similar values ​​with the international literature.
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    Avaliação comportamental e eletrofisiológica do processamento auditivo central em indivíduos com traumatismo cranioencefálico leve pré e pós-treinamento auditivo acusticamente controlado
    (Universidade Federal de São Paulo (UNIFESP), 2019-05-28) Buriti, Ana Karina Lima [UNIFESP]; Gil, Daniela [UNIFESP]; http://lattes.cnpq.br/6363626867862971; http://lattes.cnpq.br/0641682808873805; Universidade Federal de São Paulo (UNIFESP)
    Objective: To characterize and compare the behavioral and electrophysiological assessments of the central auditory processing in individuals with mild degree of traumatic brain injury, pre, post and after 6 months of acoustically controlled auditory training. Method: The sample was composed of ten individuals between 16 and 64 years after mild traumatic brain injury who underwent behavioral assessment of central auditory processing and electrophysiological assessment of hearing before and after the acomplishment of an acoustically controlled auditory training, which was organized in ten sessions. After concluding the stimulation program, we applied a self-assessment questionnaire. In order to assess the stability of the measurements, the individuals were invited to undergo a new re-assessment six months after the acoustically controlled auditory training. Results: In the behavioral assessment of central auditory processing, we noted changes in all tests, with a higher emphasis on speech in noise (90%), followed by the duration standard (80%). By comparing the pre and post assessments, we noted a statistically significant difference in the speech in noise tests in the left ear, dichotic of alternating disyllables in the right ear, sound localization and Random Gap Detecton Fusion, with better results after the acoustically controlled auditory training. In the electrophysiological assessment, we noted changes in the brain stem in the pre-assessment, besides adequacy in 100% of the individuals for wave III latency and I-III interspike interval on the right. In the assessment of the frequency following response, we noted changes in all waves due to latency delay and/or component absence, mainly for D, E, F and O waves; and after the auditory training, D and E waves on the right. For the cognitive potential, we noted a statistically significant difference for the left P3 amplitude with speech stimulus. Between the pre and post assessments, we noted P300 adequacy in 100% of the individuals on the left ear with tone burst stimulus in the post-assessment. In the self-assessment questionnaire, we noted a higher concentration of responses in a significant improvement for auditory performance aspects in noisy environments, attention and alertness level, as well as self-esteem. Conclusion: The individuals with mild traumatic brain injury show central auditory processing disorder in both behavioral and electrophysiological assessments, which was minimized after the acoustically controlled auditory training.
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    Characterization of the acute cardiac electrophysiologic effects of ethanol in dogs
    (Blackwell Publishing, 2007-09-01) Fenelon, Guilherme [UNIFESP]; Balbao, Carlos Eduardo Bissolli [UNIFESP]; Fernandes, Rinaldo Carvalho [UNIFESP]; Arfelli, Elerson [UNIFESP]; Landim, Priscila [UNIFESP]; Ayres, Otavio [UNIFESP]; De Paola, Angelo Amato Vincenzo [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Background: Alcohol has been related to atrial fibrillation (holiday heart syndrome), but its electrophysiologic actions remain unclear. Methods: We evaluated the effects of alcohol in 23 anesthetized dogs at baseline and after 2 cumulative intravenous doses of ethanol: first dose 1.5 ml/kg (plasma level 200 mg/dl); second dose 1.0 ml/kg (279 mg/dl). in 13 closed-chest dogs (5 with intact autonomic nervous system, 5 under combined autonomic blockade and 3 sham controls), electrophysiologic evaluation and monophasic action potential (MAP) recordings were undertaken in the right atrium and ventricle. in 5 additional dogs, open-chest biatrial epicardial mapping with 8 bipoles on Bachmann's bundle was undertaken. in the remaining 5 dogs, 2D echocardiograms and ultrastructural analysis were performed. Results: in closed-chest dogs with intact autonomic nervous system, ethanol had no effects on surface electrocardiogram and intracardiac variables. At a cycle length of 300 milliseconds, no effects were noted on atrial and ventricular refractoriness and on the right atrial MAP. These results were not altered by autonomic blockade. No changes occurred in sham controls. in open-chest dogs, ethanol did not affect inter-atrial conduction time, conduction velocity, and wavelength. Atrial arrhythmias were not induced in any dog, either at baseline or after ethanol. Histological and ultrastructural findings were normal but left ventricular (LV) ejection fraction decreased in treated dogs (77 vs. 73 vs. 66%; p = 0.04). Conclusion: Ethanol at medium and high doses depresses LV systolic function but has no effects on atrial electrophysiological parameters. These findings suggest that acute alcoholic intoxication does not directly promote atrial arrhythmias.
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    Contribuição diagnóstica da avaliação eletrofisiológica visual em pacientes atendidos em hospital universitário
    (Conselho Brasileiro de Oftalmologia, 2003-01-01) Sacai, Paula Yuri [UNIFESP]; Berezovsky, Adriana [UNIFESP]; Fantini, Sérgio Costa; Salomão, Solange Rios [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    PURPOSE: To determine the frequency of diagnostic categories obtained in a clinical vision electrophysiology laboratory at a university hospital. METHODS: Patients who underwent visual electrodiagnostic testing from October 1998 to October 2000 (N=570) were cross-sectionally studied. Electroretinogram (ERG) was performed in 385 (68%) patients and pattern and/or flash visually evoked potentials were performed in 185 (32%) patients. RESULTS: After electroretinogram assessment, the most frequently identified diagnostic categories were (in this order): retinitis pigmentosa, Stargardt's disease, cone dystrophy, cone-rod degeneration, retinotoxic effects due to several agents (chloroquine, tamoxifen, methanol, etc) and ocular trauma, besides unclear visual loss. In 23% of the cases, it was impossible to obtain a final diagnosis on the first examination. The largest group referred to electroretinogram testing was for documentation or exclusion of tapetoretinal degenerations (42%). In this group, 110 cases of RP were identified: 91 isolated and 19 syndromic cases. Visually evoked potential testing helped to identify the following diagnostic categories: diseases affecting only the optic nerve (optic nerve atrophy, optic neuritis, optic disk edema, etc); neurological conditions affecting the visual pathway (multiple sclerosis, cerebral palsy, blunt head trauma, tumors, etc): pediatric eye and/or neurological conditions (congenital cataract, cortical visual impairment, congenital glaucoma, etc) and opaque media (leucoma, ocular trauma, etc). CONCLUSIONS: Frequent and meaningful indications for visual electrophysiologic recording and diagnostic decisions arise from this relatively large group of studied patients. A number of diagnoses can hardly, if not all, be established without visual electrophysiologic testing. These include early stages of retinitis pigmentosa, progressive cone dystrophy, toxic retinopathy without fundus changes, optic nerve or retinal dysfunction in opaque media, optic nerve involvement in multiple sclerosis and pediatric eye disease with or without neurological damage.
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    Dysfunction in the fellow eyes of strabismic and anisometropic amblyopic children assessed by visually evoked potentials
    (Consel Brasil Oftalmologia, 2016) Andrade, Eric Pinheiro [UNIFESP]; Berezovsky, Adriana [UNIFESP]; Sacai, Paula Yuri [UNIFESP]; Pereira, Josenilson Martins [UNIFESP]; Rocha, Daniel Martins [UNIFESP]; Salomao, Solange Rios [UNIFESP]
    Purpose: To evaluate visual acuity and transient pattern reversal (PR) visual evoked potentials (VEPs) in the fellow eyes of children with strabismic and/or anisometropic amblyopia. Methods: Children diagnosed with strabismic and/or anisometropic amblyopia were recruited for electrophysiological assessment by VEPs. Monocular grating and optotype acuity were measured using sweep-VEPs and an Early Treatment Diabetic Retinopathy Study chart, respectively. During the same visit, transient PR-VEPs of each eye were recorded using stimuli subtending with a visual angle of 60', 15', and 7.5'. Parameters of amplitude (in mu V) and latency (in ms) were determined from VEP recordings. Results: A group of 40 strabismic and/or anisometropic amblyopic children (22 females: 55%, mean age = 8.7 +/- 2.2 years, median = 8 years) was examined. A control group of 19 healthy children (13 females: 68.4%, mean age = 8.2 +/- 2.6 years, median = 8 years) was also included. The fellow eyes of all amblyopes had significantly worse optotype acuity (p = 0.021) than the control group, regardless of whether they were strabismic (p = 0.040) or anisometropic (p = 0.048). Overall, grating acuity was significantly worse in the fellow eyes of amblyopes (p = 0.016) than in healthy controls. Statistically prolonged latency for visual angles of 15' and 7.5' (p = 0.018 and 0.002, respectively) was found in the strabismic group when compared with the control group. For the smaller visual stimulus (7.5'), statistically prolonged latency was found among all fellow eyes of amblyopic children (p< 0.001). Conclusions: The fellow eyes of amblyopic children showed worse optotype and grating acuity, with subtle abnormalities in the PR-VEP detected as prolonged latencies for smaller size stimuli when compared with eyes of healthy children. These findings show the deleterious effects of amblyopia in several distinct visual functions, mainly those related to spatial vision.
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    Effects of A1 receptor agonist/antagonist on spontaneous seizures in pilocarpine-induced epileptic rats
    (Academic Press Inc Elsevier Science, 2016) Amorim, Beatriz Oliveira; Hamani, Clement; Ferreira, Elenn; Miranda, Maisa Ferreira; Fernandes, Maria Jose S.; Rodrigues, Antonio M.; de Almeida, Antonio-Carlos G.; Covolan, Luciene
    Adenosine is an endogenous anticonvulsant that activates pre- and postsynaptic adenosine A(1) receptors. A(1) receptor agonists increase the latency for the development of seizures and status epilepticus following pilocarpine administration. Although hippocampal adenosine is increased in the chronic phase of the pilocarpine model, it is not known whether the modulation of A(1) receptors may influence the frequency of spontaneous recurrent seizures (SRS). Here, we tested the hypothesis that the A(1) receptor agonist RPia ([R]-N-phenylisopropyladenosine) and the A(1) antagonist DPCPX (8-Cyclopentyl-1,3-dipropylxanthine) administered to chronic pilocarpine epileptic rats would respectively decrease and increase the frequency of SRS and hippocampal excitability. Four months after Pilo-induced SE, chronic epileptic rats were video-monitored for the recording of SRS before (basal) and after a 2-week treatment with RPia (25 mu g/kg) or DPCPX (50 mu g/kg). Following sacrifice, brain slices were studied with electrophysiology. We found that rats given RPia had a 93% nonsignificant reduction in the frequency of seizures compared with their own pretreatment baseline. In contrast, the administration of DPCPX resulted in an 87% significant increase in seizure rate. Nontreated epileptic rats had a similar frequency of seizures along the study. Corroborating our behavioral data, in vitro recordings showed that slices from animals previously given DPCPX had a shorter latency to develop epileptiform activity, longer and higher DC shifts, and higher spike amplitude compared with slices from nontreated Pilo controls. In contrast, smaller spike amplitude was recorded in slices from animals given RPia. In summary, the administration of A(1) agonists reduced hippocampal excitability but not the frequency of spontaneous recurrent seizures in chronic epileptic rats, whereas A(1) receptor antagonists increased both. (C) 2016 Elsevier Inc. All rights reserved.
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    Estudo do efeito de supressão no potencial evocado auditivo de tronco encefálico
    (Pró-Fono Produtos Especializados para Fonoaudiologia Ltda., 2010-09-01) Matas, Carla Gentile [UNIFESP]; Silva, Fernanda Nivoloni O; Leite, Renata Aparecida; Samelli, Alessandra Giannella; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
    BACKGROUND: the suppression effect with contralateral white noise observed in the brainstem auditory evoked potential can be influenced by the efferent auditory system. AIM: to evaluate the suppression effect with contralateral white noise in the Brainstem Auditory Evoked Potential of individuals with normal hearing. METHODS: 25 individuals, ranging in age from 18 to 30 years, of both genders, were submitted to a clinical history questionnaire, inspection of the external auditory canal, conventional audiometry, speech audiometry and acoustic immittance measurements. Only individuals with normal hearing thresholds were selected. The selected individuals underwent brainstem auditory evoked potential testing with and without contralateral white noise. RESULTS: a significant statistical difference was observed between the situations with and without contralateral white noise, for wave I amplitude and waves III and V latencies. No statistical differences were observed for the interpeak latencies. CONCLUSION: the present study indicated increased latencies and reduced amplitudes of waves I, III and V with contralateral noise, when comparing the situations with and without noise. These results suggest a possible influence of the efferent auditory system on the response modulation of Brainstem auditory evoked potential when contralateral white noise is used.
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    Estudo eletrofisiológico in vitro da excitabilidade hipocampal do Proechimys gr. guyannensis durante o desenvolvimento pós-natal
    (Universidade Federal de São Paulo (UNIFESP), 2010-03-31) Ueda, Erika Sayuri [UNIFESP]; Cavalheiro, Esper Abrão [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The immature brain presents increased excitability where the occurrence of neuronal synchronization is facilitated. These features make the immature brain more susceptible to generate seizures. Although the causes and consequences of hyperexcitability in the immature brain are not well understood, recent studies have been focused on the development of appropriate strategies for prevention and / or reduction of epileptiform events and their possible consequences in the short and long term, aiming to ensure the normal development of the central nervous system. Previous studies in our laboratory showed that Proechimys gr. guyannensis (Proechimys), a rodent from Amazon, do not develop epilepsy when subjected to experimental models (pilocarpine, kainic acid and kindling) as other laboratory animals. This resistance to experimental epileptogenesis has been considered to be related to possible endogenous brain mechanisms that prevent the chronic development of epilepsy in this specie. This resistance of the Proechimys brain to develop epilepsy has been supported by preliminary data that hippocampal slices present lower susceptibility to convulsant agents (eg, bicuculline). Therefore, the aim of this Thesis was to study the hippocampal electrophysiological characteristics of the Proechimys from birth to adulthood, and compare with observations made in Rattus norvegicus (Wistar) in the same age periods. These studies were performed in hippocampal slices bathed with normal artificial cerebrospinal fluid and in situations promoting hyperexcitability (High Potassium, Zero Calcium or Bicuculline Models). The typical orthodromic responses of CA1 pyramidal layer could be recorded since P0-5 in Proechimys and were similar to those observed in other age subgroups of this specie. The sensitivity of the Proechimys to the High Potassium Model was also observed since birth and was characterized by epileptiform events, predominantly in P0-5 and P13-16. Similarly, the resistance of Proechimys to the Bicuculline Model was observed since after birth. High concentrations of bicuculline (30 and 50μM) induced similar responses to those reported in rats submitted to low concentrations of the same antagonist (10μM). The blockade of chemical synaptic interactions with the Zero Calcium Model in Proechimys induced spontaneous and recurrent epileptiform events, without bursts, in all age groups studied. Altogether, these results indicate that Proechimys gr. guyannensis presents an advanced maturational stage of the central nervous system at birth. Proechimys hippocampal slices submitted to in vitro models of hyperexcitability lead to similar responses during the entire developmental period. Furthermore, the mechanisms of GABAergic inhibition and synchronization of non-synaptic circuit in the CA3-CA1 may be related to a lower neuronal recruitment in this species, and consequently, the characteristic resistance to epilepsy models.
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    Estudo eletrofisiológico in vitro do hipocampo e da suscetibilidade frente a dois modelos experimentais de epilepsia no roedor Trinomys yonenagae
    (Universidade Federal de São Paulo (UNIFESP), 2009-04-29) Nascimento, André Luiz do [UNIFESP]; Cavalheiro, Esper Abrão [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Trinomys yonenagae (TY) is a fossorial rodent dweller of sand dunes of the Caatinga, pertaining to Echimydae family and known locally as rabo de facho. The observation of some animals of this species show spontaneous seizures stimulated us the study of some characteristics of its nervous system that could to be subjacents to this condition. Through techniques of eletrophysiology in vitro, with the utilization of protocols of induction of hiperexcitability and study of the long-term potentiation (LTP), we aimed at to identifying the eletrophysiologic pattern of hippocampal circuitry of the TY and comparing it to Wistar rats. Additionaly, we also aimed at verifying how animals of the TY species behave regarding two classic models of epilepsy induction: amygdala kindling and systemic aplication of pilocarpine. In the high potassium protocol, we observed in TY a higher sensibility to gradual increase of potassium in the artificial cerebrospinal fluid (ACSF). In the protocol of addition of antagonist of GABAA receptor (bicuculine) in the ACSF, we did not observe any significative differences in the extracellular records between TY and Wistar. In the absence magnesium protocol in the ACSF, both species showed spontaneous epileptiform activity, and when both species were submited to electric stimulation, their responses did not differ statisticaly. In the study of LTP, we observed that, although the normalized slopes averages in TY have showed always smaller than of Wistar after high frequence stimulus, these values between the two species did not differ statistically. The electroencephalographic and behavioral data were similar between TY and Wistar in the two epilepsy induction models, with exception of the pilocarpine dosage used to elicite status epilepticus in TY, that was lower. The electrophysiological characterization and the obtained results against the epilepsy models are interesting contributions to the knowledge of the nervous system of the TY and reveal the importance to futures works in this species for the acquisition of new knowledges that can to be involved in the genesis of the seizures.
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    Estudo normativo do eletrorretinograma por padrões (PERG) em adultos
    (Conselho Brasileiro de Oftalmologia, 2010-06-01) Alves, Letícia Dourado [UNIFESP]; Berezovsky, Adriana [UNIFESP]; Sacai, Paula Yuri [UNIFESP]; Pereira, Josenilson Martins [UNIFESP]; Salomão, Solange Rios [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Purpose: To determine normative values for pattern-reversal electroretinogram (PERG) in healthy adult volunteers according to the standard protocol recommended by the International Society for Clinical Electrophysiology of Vision-ISCEV. Methods: Participants were 30 healthy volunteers (15 males) with ages from 18 to 61 years (mean= 30.8 ± 8.7 yrs.; median= 29.5 yrs). Inclusion criteria were: visual acuity of 0.0 logMAR (20/20 Snellen) in each eye, absence of visual complaints, absence of media opacities, negative history for ocular or neurological diseases, negative family history for ocular and informed consent. PERG was recorded from each eye in a darkened room at 1 m from a high resolution display monitor. Stimuli were monochromatic checkerboards subtending 60, 15 e 7.5 minutes of visual angle reversing at 1.9 Hz. Responses were obtained from modified disposable fiber electrodes developed at UNIFESP. Latency (ms) for N35, P50 and N95 components as well as peak-to-peak amplitudes (µV) for N35-P50 and P50-N95 were determined. For normative values only one randomly chosen eye was included. Normal limits were calculated as 97.5% percentiles for latency and 2.5% percentile for amplitudes for each stimulus size. Results: Normal limits for N35, P50 and N95 latencies for 60', 15' and 7.5' stimuli were respectively: N35 - 40.1; 39.9 and 41.3 ms; P50 - 60.5; 64.4 and 65.6 ms and N95 - 103.4; 104.6 and 104.6 ms. For amplitude the normative values for N35-P50 and P50-N95 for 60', 15' and 7.5' were respectively: N35-P50 - 1.7; 1.6 and 0.9 µV; P50-N95 - 3.8; 2.8 and 1.5 µV. No gender differences were found either for latency or for amplitude in the three stimulus sizes. There was no correlation between PERG latency and amplitude with age, except for P50 amplitude for stimulus 15'(r=0.39; P=0.035). Conclusions: Normative values were determined for PERG parameters of amplitude and latency for three stimulus sizes. These parameters are important for evaluating the normal functioning of retinal ganglion cells and the macula. The normative values obtained in this study are comparable to previous studies in the literature.
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    Função do núcleo paratrigeminal na homeostase circulatória e reflexos cardiorrespiratórios
    (Universidade Federal de São Paulo (UNIFESP), 2010-03-31) Sousa, Luana de Oliveira [UNIFESP]; Lindsey, Charles Julian [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Recentes investigações inserem 0 núcleo paratrigeminal entre 0 grupo de estruturas bulbares relacionadas ao controle homeostático. Para compreender sua participação nestes mecanismos avaliamos 0 efeito da lesão neuroquímica do núcleo, ou de suas sub-regiões, na resposta reflexa a estímulos pressores e depressores durante diferentes períodos pós ablação da estrutura. Também avaliamos 0 atividade elétrica neuronal através de registro simultâneo de muitos neurônios ou "multi-chonnel ensemble recording” durante alterações da pressão arterial. Os resultados mostraram que a integridade do núcleo é fundamental para a manutenção da pressão arterial de repouso como também para os componentes de compensação cardíaca e de tamponamento do simpático-vascular barorreflexos aos aumentos ou diminuições da pressão arterial. Aparentemente 0 núcleo parotrigeminal atuaria em tamponar pequenos e médios alterações da pressão arterial, dentro da faixa de oscilações das batidas cardíacas (40 mmHg em ratos), enquanto que 0 núcleo do trato solitário (NTS) atuaria tamponando as maiores alterações da pressão, sugerindo que as estruturas atuem com funções complementares. Lesões seletivas do núcleo paratrigeminal ossociaram a porção caudal à função barorreflexa e a porção interpolar e rostral na manutenção do tônus vascular e ou simpático. Uma estreito coluna de neurônios no aspecto lateral da região interpolar/caudal do núcleo teria importância fundamental para a manutenção do tônus vascular e pressão arterial de repouso. 0 decurso temporal dos efeitos da lesão do núcleo evidência a adaptação e plasticidade das redes neurais levando 0 uma reorganização para substituir funcionalmente a estrutura danificado. 0 registro simultâneo de neurônios paratrigeminais mostrou uma atividade elétrica compatível ao esperado de neurônios sensíveis à estimulação pressoceptora, observados no NTS. Evidência de recrutamento neuronal ocorre durante a fase ascendente da resposta pressora e a redução no número de neurônios que aumentaram a atividade elétrica no pico do efeito pressor pode refletir a cessação do efeito do recrutamento, possivelmente como parte do processo de resetting de curto prazo dos barorreceptores. Também, 0 número de neurônios que diminuíram ou aumentaram a taxa de disparo durante os eventos pressores e depressores pode representar a desativação ou ativação quimioreceptora, em resposta ao aumento ou queda do pressão arterial, respectivamente. Similar ao NTS, aproximadamente 90% dos neurônios paratrigeminois apresentaram atividade rítmico atrelada ao ciclo cardíaco, a maioria com múltiplos picos com distintas frequências, e grande proporção de neurônios com atividades rítmicas altamente sincronizadas com 0 rítmo respiratório ou outros. A assimetria e a falta de coerêncio da atividade dos neurônios frente a alterações opostas da pressão arterial, os múltiplos picos associados a atividade rítmicas sugere que 0 núcleo, além das aferências bororreceptoras receba também aferências convergentes, excitatórias e inibitórias, de origem quimioreceptora, cardiopulmonar, somatosensorial e ou nociceptiva. As informações convergentes ao núcleo seriam processadas 'por redes neurais e repassadas às outras estruturas bulbares relacionadas à homeostase cordiovascular e respiratória. Os dados apontam homologias entre o núcleo paratrigeminal e 0 NTS e, do ponto de vista evolutivo, o núcleo paratrigeminal poderia ser uma diferenciação funcional do NTS, próprio para fornecer ajustes finos e rápidos requeridos nos animais homeotermos..
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    Investigação funcional do canal para potássio KIR2.6: novas perspectivas para o Gating do canal
    (Universidade Federal de São Paulo (UNIFESP), 2021) Paninka, Rolf Matias [UNIFESP]; Miranda Filho, Manoel de Arcisio [UNIFESP]; Universidade Federal de São Paulo
    The lipidic nature of the plasma membrane constitutes a barrier to the passage of electrically charged particles solvated in water. Ion channels are integral membrane proteins connecting the internal and external media of the cell allowing the passage of specific ions in a highly selective way. This work discusses a peculiar family of potassium channels called Kir, which stands for “Potassium inward rectifier”. Kir channels resemble a diode, allowing K+ to flow more easily into the cells, but limiting the flow in the reverse direction. Kir2.6 channel, encoded by the KCNJ18 gene, has been linked to a clinical condition called Thyrotoxic Periodic Paralysis (TPP). At the first part of the thesis, the direct DNA sequencing of two patients diagnosed with PPT, revealed two heterozygous mutations of the KCNJ18 gene: D252N and R386C, respectively. cDNAs of Kir2.6 wild-type (WT) channels and their mutants were transiently transfected to Embryonic Human Kidney cells (HEK293T) and analyzed by electrophysiology (voltage-clamp at whole-cell mode) and confocal laser scanning microscopy. D252N mutation showed a decrease in the current density of the channel in the order of 34%, when compared to the wild Kir2.6 (WT) channel. In addition, this mutation had a negative dominant effect when co-transfected in proportion of 50% with the Kir2.6 WT channel. Finally, D252N mutation demonstrated a substantial reduction (~ 51%) on membrane abundance of the channel compared to Kir2.6 WT channel. R386C mutation showed no significant change in comparation to Kir2.6 WT channel. At the second part of the thesis, the gating (the opening and closing mechanism) of the channel was investigated. For this purpose, two regions of the channel were selected so far not mentioned in the literature and, through a technique called alanine scanning, 20 amino acids of the channel-forming protein were systematically mutated by alanine. In doing so, we aim to study the individual contribution of each of these amino acids to the stability and functioning of the channel region located at the outer leaf of the plasma membrane.20 Using the same methodology used in the first part, nine amino acids were identified that proved to be critical for maintaining the conductive state of the channel: F102, W103, I105, A106, A158, V159, V162, and Q165. Six of them are in symmetrical positions in the first and second transmembrane segments of the channel-forming monomer: F102, I105, A106 are at the first segment and, A158, V159 and V162 are at the second segment. This suggests that these three pairs of amino acids may be important in maintaining the stability of the ion-conducting pore. In addition, the alignment of the total length of the protein between the Kir channel family (KCNJ1-KCNJ18) and the molecular analysis of distances between the amino acids at the pore region of the channel, showed possible interactions between amino acids F102 and F136, as well as between amino acids W103 and F130. The alanine mutation of the amino acids F130 and F136 revealed data consistent with this hypothesis, since the electrophysiological analysis showed total and partial suppression, respectively, of the channel activity. Our results suggest that these amino acids are important for maintaining the channel structure and the stability of the ion conducting pore and that there may be a mechanism for opening and closing the channel positioned in the most extracellular portion of the transmembrane domain of the channel.
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    P300 in individuals with sensorineural hearing loss
    (Assoc Brasileira Otorrinolaringologia & Cirurgia Cervicofacial, 2015-03-01) Mirandola Barbosa Reis, Ana Claudia; Figueiredo Frizzo, Ana Claudia; Isaac, Myriam de Lima; Dutra Garcia, Cristiane Fregonesi; Rodrigues Funayama, Carolina Araujo; Iorio, Maria Cecilia Martinelli [UNIFESP]; Universidade de São Paulo (USP); Univ Estadual Paulista; Universidade Federal do Rio de Janeiro (UFRJ); Universidade Federal de São Paulo (UNIFESP)
    Introduction: Behavioral and electrophysiological auditory evaluations contribute to the understanding of the auditory system and of the process of intervention.Objective: To study P300 in subjects with severe or profound sensorineural hearing loss.Methods: This was a descriptive cross-sectional prospective study. It included 29 individuals of both genders with severe or profound sensorineural hearing loss without other type of disorders, aged 11 to 42 years; all were assessed by behavioral audiological evaluation and auditory evoked potentials.Results: A recording of the P3 wave was obtained in 17 individuals, with a mean latency of 326.97 ms and mean amplitude of 3.76 V. There were significant differences in latency in relation to age and in amplitude according to degree of hearing loss. There was a statistically significant association of the P300 results with the degrees of hearing loss (p = 0.04), with the predominant auditory communication channels (p < 0.0001), and with time of hearing loss. 3Conclusions: P300 can be recorded in individuals with severe and profound congenital sensorineural hearing loss; it may contribute to the understanding of cortical development and is a good predictor of the early intervention outcome. (C) 2015 Associacao Brasileira de Otorrinolaringologia e Cirurgia Cervico-Facial. Published by Elsevier Editora Ltda. All rights reserved.
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    Padronização normativa de eletro-oculografia em adultos
    (Conselho Brasileiro de Oftalmologia, 2004-04-01) Munhoz, Juliana Simões; Salomão, Solange Rios [UNIFESP]; Berezovsky, Adriana [UNIFESP]; Sacai, Paula Yuri [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    PURPOSE: To determine normative values for EOG in a group of healthy adult volunteers, according to the standard protocol recommended by the International Society for Clinical Eletrophisiology of Vision - ISCEV. METHODS: 33 volunteers aging from 18 to 55 years (mean=26.75±10.50) were included in the study. EOG was recorded by skin electrodes positioned in the external canthi of the eyes, with LED stimulus presented in a Ganzfeld dome. Subject's task was to fix the LED stimulus either straight ahead or with saccadic horizontal movements. The potential difference between the cornea and posterior pole of the eye was recorded each minute. The examination was done in 3 phases: 1- pre-adaptation; 2- dark (scotopic) and 3- light (photopic). The Arden ratio was calculated as the proportion between the maximum peak amplitude in the light phase divided by the minimum peak amplitude in the dark. RESULTS: At the scotopic phase, the minimum peak amplitude occurred between 14 and 21 minutes after the beginning of the stimulation (mean=17.82±2.11 min) and the amplitude ranged from 206 to 635 µV (mean 365.73±122.52 µV). At the photopic phase the maximun peak amplitude occurred between 27 and 34 minutes (mean=30.06±1.80 min); the amplitude ranged from 646 to 1250 µV (mean= 950.70±179.16 µV). Arden ratio ranged from 1.85 to 4.02 with a lower normal limit of 1.92 and the upper limit of 4.00. CONCLUSION: The results obtained in this study are comparable to those previously reported in the literature, with a lower normal limit of 1.92 for Arden ratio. These values will be helpful to evaluate patients with several retinal disorders. Inclusion of other age groups will provide extended normative data.
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    Potencial evocado auditivo de tronco encefálico por via óssea em indivíduos com perda auditiva sensorioneural
    (CEFAC Saúde e Educação, 2013-06-01) Fernandes, Luciana Castelo Branco Camurça [UNIFESP]; Gil, Daniela [UNIFESP]; Maria, Samylla Lopes de Santa; Azevedo, Marisa Frasson de [UNIFESP]; Universidade Estadual de Ciências da Saúde de Alagoas; Universidade Federal de São Paulo (UNIFESP)
    PURPOSE: to characterize the results of ABR via bone in subjects with mild sensorineural hearing loss, comparing these data with the control group made up by subjects with normal hearing. METHOD: the sample consisted of 40 adults of both genders, 18 - 55 year old, divided into a control group of 30 subjects with normal hearing and a study group made up of 10 subjects with mild sensorineural hearing loss. ABR was carried out with Interacoustics brand EP15. The stimulus was the click presentation rate of 27.7 / s, for a total of 2000 stimuli with rarefaction polarity for AC and switched to VO and band-pass filter of 50Hz and 3000Hz. RESULTS: in subjects with mild sensorineural loss, there were no statistically significant differences between the ABR threshold via air and bone, and those thresholds were equivalent, with air-bone gap of less than 10dB. The latencies of wave V in the electrophysiological threshold and 50 dBnNA were lower latencies than those noted in subjects with normal hearing. CONCLUSION: we found electrophysiological thresholds via bone equivalent to thresholds obtained via air, with the presence of air-bone gap being less than 10dBnNA. Thus, the use of VO by ABR provides data for a more-detailed characterization of the type of hearing loss.
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    Repercussão cerebral após um insulto isquêmico no roedor neotropical Proechimys
    (Universidade Federal de São Paulo (UNIFESP), 2019-11-28) Villatoro, Nancy Nohemi Ortiz [UNIFESP]; Bahi, Carla Alessandra Scorza [UNIFESP]; http://lattes.cnpq.br/1780763516426752; http://lattes.cnpq.br/4545602619091705; Universidade Federal de São Paulo (UNIFESP)
    Stroke is a serious public health problem with a limited treatment option and narrow therapeutic window and therefore available only to about 5% of patients. It is the second leading cause of death worldwide and, in addition to its high incidence and high mortality rates, stroke is highly disabling. Approximately 87% of all cases correspond to ischemic stroke. This work strengthens the usefulness of investigating the responses elicited by induced brain injury in a non-conventional animal model, the Proechimys rodent. This exotic wildlife species of the Amazon rainforest seems to have a better restorative mechanism to recover from cortical photothrombotic infarction as compared with the traditional laboratory Wistar rats. Focal cortical photothrombotic stroke was induced in male Proechimys and Wistar rats. Experiments were performed 24-h and 30days after injury. Blood brain barrier (BBB) permeability was assessed by measuring Evans blue extravasation, infarct volume by mitochondrial viability and by stereological estimation of Nissl-stained slices, glial activation by immunofluorescence, brain levels of inflammatory cytokines and growth factors by ELISA, neuronal death estimated by total number of cresyl violet stained neurons. Brain tissue excitability was evaluated by cortical spreading depression phenomenon and by long-term electroencephalographic recordings (EEG). The Proechimys rodent group showed lower blood-brain barrier permeability, smaller volume of ischemic infarction and lesser glial activation than Wistar group. Substantially lower neuronal loss was detected in both perilesional area and ipsilateral thalamus of Proechimys as compared with Wistar. In contrast to Wistar rats, post-stroke decreased levels of pro-inflammatory cytokines and increased levels of anti-inflammatory mediators and growth factors were found in Proechimys. Differences in cortical electrophysiological features associated with lesion were detected between animal species subjected to spreading depression induction suggesting a lower post-stroke impact in the brain of Proechimys. A major finding of our study is that ischemic injury did not lead to epilepsy in Proechimys whereas 88% of the Wistar rats developed post-stroke epilepsy. Our findings highlight singular endogenous antiepileptogenic mechanisms and post-stroke recovery capabilities in Proechimys. As emergent interest in epilepsy research is the understanding of neurobiological processes for preventing post-stroke epileptogenesis or minimizing its effects, Proechimys may prove to be a useful animal model in identifying antiepileptogenic mechanisms to enable the design of disease-modifying approaches.