Ictal SPECT in Psychogenic Nonepileptic and Epileptic Seizures.

BACKGROUND: Psychogenic nonepileptic seizures (PNES) are a common and debilitating problem in patients with epilepsy. They can be virtually indistinguishable from epileptic seizures, demanding video-electroencaphalogram monitoring, which is costly and not widely available, for differential diagnosis. Specific functional brain correlates of PNES have not been demonstrated so far. We hypothesized that PNES and epileptic seizures have distinct brain activation patterns, assessed by functional neuroimaging during ictal events of both conditions. OBJECTIVE: Compare ictal brain activation patterns of PNES and epileptic seizures using single-photon emission computerized tomography. METHODS: We prospectively assessed brain functional activation using single-photon emission computerized tomography 99mTc-ethyl cysteinate dimer in 26 patients with PNES, confirmed by trained psychiatrists in epileptology, who had their seizures induced by provocative tests compared with 22 age- and sex-matched subjects with temporal lobe epilepsy who underwent prolonged intensive video-electroencaphalogram monitoring. RESULTS: In PNES patients compared with temporal lobe epilepsy group, we found a consistent increase in regional cerebral blood flow in the right precuneus (Brodmann area 7; P = 0.003) and right posterior cingulate cortex (Brodmann area 31; P = 0.001), as well as a decrease in regional cerebral blood flow in the right amygdala (P = 0.027). CONCLUSIONS: Activation of default mode network brain areas and temporoparietal junction may be a distinct feature of ictal PNES and could be explained by a disruption between movement prediction input and sensory outcome. Such information mismatch might be the neurobiological underpinning of dissociative episodes.

Immunization stress-related responses presenting as psychogenic non-epileptic seizures following HPV vaccination in Rio Branco, Brazil.

IMPORTANCE: The absence of a positive diagnosis of psychogenic non-epileptic seizures (PNES) in immunization stress-related response (ISRR) clusters may have not only a direct impact on affected patients' health but may also reduce compliance to national vaccination programs. It is therefore crucial to develop efficient diagnostic tools and a feasible proposal for proper communication and treatment of ISRR. PURPOSE: To explore the psychogenic nature of patients' convulsive seizures in a suspected outbreak of an ISRR cluster following human papillomavirus vaccination in Rio Branco, Brazil. METHODS: Twelve patients with convulsive seizures were submitted to prolonged intensive video-electroencephalography monitoring, brain magnetic resonance imaging, cerebrospinal fluid diagnostic testing, laboratory subsidiary examinations, and complete neurological and psychiatric evaluations. RESULTS: Ten patients received the positive diagnosis of PNES, and two patients received the diagnosis of idiopathic generalized epilepsy. No biological association was found between the HPV vaccine and the clinical problems presented by the patients. CONCLUSIONS: Prolonged VEEG monitoring can contribute significantly to the positive diagnosis of PNES in ISRR clusters and to avoid hesitancy to vaccinate.

Proton spectroscopy of the thalamus in a homogeneous sample of patients with easy-to-control juvenile myoclonic epilepsy.

OBJECTIVE: Juvenile myoclonic epilepsy (JME) is a subtype of genetically determined generalized epilepsy that does not present abnormalities on conventional magnetic resonance imaging. The aim of this study was to identify metabolic alterations in the thalamus in a clinically homogeneous sample of patients with easy-to-control JME, using short-echo time proton magnetic resonance spectroscopy (MRS). MATERIALS AND METHODS: We performed single-voxel (2 cm × 2 cm × 2 cm), short-echo time (TE = 35 ms) proton MRS of the thalamus in 21 patients with JME and in 14 healthy age-matched controls. We quantified N-acetylaspartate (NAA), total NAA, creatine (Cr), choline, and myo-inositol (MI), as well as the sum of glutamate and glutamine signals, all scaled to internal water content, and we calculated metabolite ratios using Cr as a reference. Values of p < 0.05 were considered significant. RESULTS: The MI level and the MI/Cr ratio were significantly lower in the thalami of patients diagnosed with JME than in those of the controls. Other metabolites and their ratios did not differ significantly between the two groups. CONCLUSION: In our sample of 21 JME patients, we identified lower levels of MI in the thalamus. No significant abnormalities were observed in the concentrations or ratios of other metabolites.

OBJETIVO: A epilepsia mioclônica juvenil (EMJ) é um dos subtipos da epilepsia generalizada geneticamente determinada que não apresenta alterações na ressonância magnética convencional. O objetivo deste estudo foi determinar se há alterações metabólicas no tálamo de pacientes com EMJ de fácil controle de uma amostra clinicamente homogênea utilizando espectroscopia de prótons por ressonância magnética (ERM) com tempo de eco curto. MATERIAIS E MÉTODOS: Nós realizamos ERM com voxel único (2 cm × 2 cm × 2 cm) e tempo de eco curto (TE = 35 ms) no tálamo de 21 pacientes com EMJ e 14 controles saudáveis pareados por idade. N-acetil-aspartato (NAA), NAA total, creatina (Cr), colina, mio-inositol (MI) e a soma de glutamato e glutamina foram quantificados em relação ao conteúdo de água interna e as razões dos metabólitos foram calculadas utilizando Cr como referência. Valor de p < 0,05 foi considerado como significante. RESULTADOS: Houve redução estatisticamente significante de MI e MI/Cr no tálamo dos pacientes diagnosticados como EMJ em relação aos controles. Outros metabólitos e suas razões não apresentaram alterações significantes. Conclusão: No tálamo do nosso grupo de 21 pacientes com EMJ foi observada redução de MI e da relação MI/Cr. Não foi observada diferença nos outros metabólitos ou suas relações.

Proton spectroscopy of the thalamus in a homogeneous sample of patients with easy-to-control juvenile myoclonic epilepsy / Espectroscopia de prótons do tálamo em uma amostra homogênea de pacientes com epilepsia mioclônica juvenil de fácil controle

Abstract Objective: Juvenile myoclonic epilepsy (JME) is a subtype of genetically determined generalized epilepsy that does not present abnormalities on conventional magnetic resonance imaging. The aim of this study was to identify metabolic alterations in the thalamus in a clinically homogeneous sample of patients with easy-to-control JME, using short-echo time proton magnetic resonance spectroscopy (MRS). Materials and Methods: We performed single-voxel (2 cm × 2 cm × 2 cm), short-echo time (TE = 35 ms) proton MRS of the thalamus in 21 patients with JME and in 14 healthy age-matched controls. We quantified N-acetylaspartate (NAA), total NAA, creatine (Cr), choline, and myo-inositol (MI), as well as the sum of glutamate and glutamine signals, all scaled to internal water content, and we calculated metabolite ratios using Cr as a reference. Values of p < 0.05 were considered significant. Results: The MI level and the MI/Cr ratio were significantly lower in the thalami of patients diagnosed with JME than in those of the controls. Other metabolites and their ratios did not differ significantly between the two groups. Conclusion: In our sample of 21 JME patients, we identified lower levels of MI in the thalamus. No significant abnormalities were observed in the concentrations or ratios of other metabolites.

Resumo Objetivo: A epilepsia mioclônica juvenil (EMJ) é um dos subtipos da epilepsia generalizada geneticamente determinada que não apresenta alterações na ressonância magnética convencional. O objetivo deste estudo foi determinar se há alterações metabólicas no tálamo de pacientes com EMJ de fácil controle de uma amostra clinicamente homogênea utilizando espectroscopia de prótons por ressonância magnética (ERM) com tempo de eco curto. Materiais e Métodos: Nós realizamos ERM com voxel único (2 cm × 2 cm × 2 cm) e tempo de eco curto (TE = 35 ms) no tálamo de 21 pacientes com EMJ e 14 controles saudáveis pareados por idade. N-acetil-aspartato (NAA), NAA total, creatina (Cr), colina, mio-inositol (MI) e a soma de glutamato e glutamina foram quantificados em relação ao conteúdo de água interna e as razões dos metabólitos foram calculadas utilizando Cr como referência. Valor de p < 0,05 foi considerado como significante. Resultados: Houve redução estatisticamente significante de MI e MI/Cr no tálamo dos pacientes diagnosticados como EMJ em relação aos controles. Outros metabólitos e suas razões não apresentaram alterações significantes. Conclusão: No tálamo do nosso grupo de 21 pacientes com EMJ foi observada redução de MI e da relação MI/Cr. Não foi observada diferença nos outros metabólitos ou suas relações.

Epilepsy in patients with psychogenic non-epileptic seizures.

The aim of this study was to evaluate the frequency of epilepsy in patients who presented psychogenic non-epileptic seizures (PNES). The evaluation was carried out during intensive VEEG monitoring in a diagnostic center for epilepsy in a university hospital. The difficulties involved in reaching this diagnosis are discussed. Ninety-eight patients underwent intensive and prolonged video-electroencephalographic (VEEG) monitoring; out of these, a total of 28 patients presented PNES during monitoring. Epilepsy was defined as present when the patient presented epileptic seizures during VEEG monitoring or when, although not presenting epileptic seizures during monitoring, the patient presented unequivocal interictal epileptiform discharges. The frequency of epilepsy in patients with PNES was 50% (14 patients). Our findings suggest that the frequency of epilepsy in patients with PNES is much higher than that of previous studies, and point out the need, at least in some cases, for prolonging the evaluation of patients with PNES who have clinical histories indicating epilepsy.

Epilepsy in patients with psychogenic non-epileptic seizures / Epilepsia em pacientes com crises não epilépticas psicogênicas

The aim of this study was to evaluate the frequency of epilepsy in patients who presented psychogenic non-epileptic seizures (PNES). The evaluation was carried out during intensive VEEG monitoring in a diagnostic center for epilepsy in a university hospital. The difficulties involved in reaching this diagnosis are discussed. Ninety-eight patients underwent intensive and prolonged video-electroencephalographic (VEEG) monitoring; out of these, a total of 28 patients presented PNES during monitoring. Epilepsy was defined as present when the patient presented epileptic seizures during VEEG monitoring or when, although not presenting epileptic seizures during monitoring, the patient presented unequivocal interictal epileptiform discharges. The frequency of epilepsy in patients with PNES was 50 percent (14 patients). Our findings suggest that the frequency of epilepsy in patients with PNES is much higher than that of previous studies, and point out the need, at least in some cases, for prolonging the evaluation of patients with PNES who have clinical histories indicating epilepsy.

O objetivo deste estudo foi avaliar a frequência de epilepsia em pacientes que apresentaram crises não epilépticas psicogênicas (CNEP). Isto foi realizado durante monitoração intensiva por video-EEG num centro diagnóstico de epilepsia em um hospital universitário. As dificuldades envolvidas para se chegar a este diagnóstico são discutidas. Noventa e oito pacientes foram submetidos a monitoração intensiva por video-EEG; 28 destes pacientes apresentaram CNEP durante a monitoração. Epilepsia foi considerada presente quando o paciente apresentou crises epilépticas durante a avaliação pelo video-EEG ou quando, apesar da não ocorrência de crises epilépticas durante a avaliação, descargas epilépticas interictais inequívocas estavam presentes. A frequência de epilepsia em pacientes com CNEP foi 50 por cento (14 pacientes). Nossos achados sugerem que a frequência de epilepsia em pacientes com CNEP é maior do que a apresentada em estudos anteriores e apontam para a necessidade de, ao menos em alguns casos, prolongar a avaliação de pacientes com CNEP, mas com história clínica sugestiva de epilepsia.

Epilepsia Mioclônica Juvenil: endofenótipos distintos considerando aspectos neuropsicológicos, traços de personalidade e variáveis clínicas / Juvenile Myoclonic Epilepsy: distinct phenotypes considering aspects neuropsychological, personality traits and variables clinics

INTRODUÇÃO: Estudos neuropsicológicos sugerem que indivíduos com EMJ apresentam disfunção executiva além de maior impulsividade, refletindo uma disfunção de lobo frontal. Este estudo teve como objetivos verificar: 1. o desempenho e gravidade de comprometimento das funções executivas; 2. presença de traços de personalidade impulsivos; 3. a correlação entre o desempenho nas funções cognitivas e a expressão de traços de personalidade impulsivos e; 4. se as variáveis da epilepsia se correlacionam com as disfunções executivas e a um pior controle de impulsos. MÉTODOS: Foram avaliados 42 pacientes com EMJ e 42 sujeitos saudáveis pareados por idade, escolaridade e nível socioeconômico, através de bateria compreensiva de testes neuropsicológicos avaliadores de funções executivas e questionário padronizado de avaliação de traços de personalidade (ITC). RESULTADOS: Pacientes com EMJ tiveram pior desempenho nos testes de atenção imediata, seletiva e sustentada; controle mental e inibitório; flexibilidade mental; fluência verbal; formação de conceitos e manutenção de metas. A disfunção executiva foi moderada/grave em 83,33 por cento. Pacientes com EMJ apresentaram maior expressão dos traços de personalidade impulsivos. A disfunção executiva se correlacionou com o pior controle dos impulsos. Pacientes refratários apresentaram pior disfunção executiva e maior expressão de traços impulsivos. CONCLUSÕES: Nosso estudo demonstra a presença de disfunção atencional e executiva nos pacientes com EMJ, além da presença de traços de personalidade impulsivos. Além disso, verificamos a existência de dois grupos distintos de pacientes, sendo que pacientes mais refratários apresentam-se globalmente comprometidos. Estes achados sugerem que há uma necessidade de melhor caracterização fenotípica dos pacientes com EMJ a fim de incluir endofenótipos visto que nossos resultados demonstram uma possível existência de grupos distintos de pacientes com EMJ.

INTRODUCTION: Neuropsychological studies suggest that patients with JME have executive dysfunction and impulsiveness, reflecting a possible frontal lobe dysfunction. This study aimed to verify: 1. the performance and severity of attentional and executive functions; 2. presence of impulsive personality traits; 3. correlation between cognitive performance and the expressions of impulsive personality traits; 4. correlation between epilepsy variables and neuropsychological performance as well as worse impulse control. METHODS: We evaluated 42 patients with JME and a group of 42 control subjects, matched for age, education and socioeconomic status with a comprehensive battery of neuropsychological tests of attentional and executive functions and a standardized assessment of personality traits (TCI). RESULTS: Patients with JME showed worse performance than controls on tests of attentional span, working memory, inhibitory control, concept formation, maintenance of goals, and verbal fluency. Executive dysfunction was severe/moderate in 83.33 percent. Patients with JME showed higher expression of personality traits associated with an impaired impulse control. Attentional/executive dysfunction was correlated with poor impulse control. Refractory patients had worse executive dysfunction with an even a greater presence of impulsive personality traits. CONCLUSIONS: Our study demonstrates the presence of attentional and executive dysfunction in patients with JME, as well as the presence of impulsive personality traits. We also note the existence of two distinct groups of patients, were more refractory patients appear to present broader impairment. These findings suggest that there is a need for better phenotypic characterization of patients with JME to include diverse phenotypes since our results suggest a possible existence of distinct groups of patients with JME.

Evaluating patients with suspected nonepileptic psychogenic seizures.

The authors evaluate 26 patients with suspected psychogenic non-epileptic seizures (PNES) who were referred to prolonged intensive video EEG (VEEG) in an epilepsy diagnostic center at the University of São Paulo, Brazil. Following the investigative protocol, 50% of the patients received a diagnosis of PNES, 15.4% of epilepsy, and 34.6% of associated PNES and epilepsy. In all patients in our series, PNES were the pseudoneurological presentations of dissociative or conversion symptoms in patients presenting the following mental disorders: conversion disorder, somatization or undifferentiated somatoform disorder, dissociative disorder not otherwise specified, and posttraumatic stress disorder. Psychiatric comorbidities, mostly depressive disorders, were frequent.

Psychiatric diagnoses of patients with psychogenic non-epileptic seizures.

OBJECTIVE: Our purpose was to present and discuss the psychiatric diagnoses of patients who presented psychogenic non-epileptic seizures (PNES) during video-electroencephalographic monitoring (VEEG). METHODS: Out of 98 patients, a total of 28 patients presented PNES during the diagnostic procedure. In those cases in which the PNES that occurred during VEEG were validated by clinical history (clinical validation), and by showing the recorded event on video to an observer close to the patient (observer validation), was defined psychogenic non-epileptic seizure disorder (PNESD). Psychiatric diagnoses were made according to DSM-IV. RESULTS: In 27, psychogenic non-epileptic seizures disorder was diagnosed. Fourteen patients presented only with psychogenic non-epileptic seizure disorder, 13 with both psychogenic non-epileptic seizures disorder and epilepsy, and one patient with epilepsy only. Psychiatric diagnoses were: 17 (63%) patients with conversion disorder, five (19%) with somatization disorder, two (7%) with dissociative disorder NOS, two (7%) with post-traumatic stress disorder and one (4%) with undifferentiated somatoform disorder. CONCLUSIONS: Dissociative-conversion non-epileptic seizures are the most frequent finding, representing the pseudoneurological manifestation of mental disorders that have these symptoms as a common feature. Provisionally, they may be defined as dissociative-conversion non-epileptic seizure disorders.

Resultados preliminares de um programa de tratamento de crises não-epilépticas psicogênicas / Preliminary results of the treatment program of psychogenic nonepileptic seizures

Apesar dos avanços no diagnóstico das crises não epilépticas psicogênicas (CNEP), até o presente momento não há tratamentos que sejam padronizados e eficientes. O presente estudo examinou a freqüência de crises e as condições de trabalho e acadêmicas em um grupo de pacientes portadores de CNEP antes e depois de completarem um programa de oito semanas específico, desenvolvido no PROJEPSI (Projeto de Epilepsia e Psiquiatria) do Instituto de Psiquiatria do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, com os objetivos de redução da freqüência de crises e de danos associados ao diagnóstico de CNEP. Ao final do programa de tratamento, 15 pacientes (62,5 por cento) apresentavam-se em remissão e 19 (79,2 por cento) apresentaram melhora do desempenho profissional ou acadêmico. O presente estudo fornece evidências da eficácia do programa de atendimento dos pacientes portadores de CNEP proposto pelo PROJEPSI. O número significativo de pacientes que apresentam remissão e redução do número de crises após a comunicação terapêutica do diagnóstico, do tratamento das comorbidades psiquiátricas e da terapia para redução de danos e crises (TRDC) sugere que o conhecimento da doença por parte dos pacientes, familiares e amigos convidados é essencial ao tratamento.

In spite of the growing interest in psychogenic nonepileptic seizures (PNES), this diagnosis clearly lacks both standard protocols and efficient treatment. We analyzed seizure frequency, as well as, academic and working performances in a group of PNES patients, both prior and following a specific eight-week program developed at PROJEPSI (Epilepsy and Psychiatry Project) - Institute of Psychiatry, Hospital de Clinicas, School of Medicine, University of Sao Paulo. The program targeted seizure reduction and decrease in losses associated to PNES. Fifteen patients (62.5 percent) entered prolonged remission and 19 (79.2 percent) improved academic and professional performances. Our study shows evidence supporting the efficacy of the NES protocol proposed by PROJEPSI. The number of patients presenting with either remission or significant decrease on their seizures following the diagnosis presentation, psychiatric comorbidity treatment and specific therapy aiming to damage and crisis suggests that the knowledge of this condition by patients, family members and friends is key to successful treatment.

Risk factors for psychogenic nonepileptic seizures in children and adolescents with epilepsy.

There is evidence that psychogenic nonepileptic seizures (PNES) remain underdiagnosed, especially in children and adolescents. Diagnosis of such events is even more difficult in patients that do have epilepsy, leading to delayed diagnosis and treatment and, consequently, iatrogenic complications. This study aimed to evaluate possible risk factors in children with epilepsy who had PNES. Seizures and epileptic syndromes were classified according to International League Against Epilepsy guidelines. Patients were evaluated with a structured psychiatric anamnesis and classified according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; Classification of Mental and Behavioral Disorders: Diagnostic Criteria for Research; and Schedule for Affective Disorders and Schizophrenia for School-Age Children--Epidemiological Version. Risk factors such as head trauma, physical, sexual and psychological abuse, and psychiatric diagnoses, among others, were investigated. Family history of epilepsy and psychiatric illness were detected by review of medical records and/or follow-up interviews. Gender was not a predictive factor, and although older children had a higher risk for PNES, younger children also presented truly psychogenic events mimicking epileptic seizures. The most common associated psychiatric diagnosis was depression. Family histories for epilepsy and psychiatric illness were a frequent finding. An inadequate family environment was more common than sexual or physical abuse. Current knowledge obtained from adults with PNES has been used to understand children with PNES. However, this study of children with epilepsy revealed some similarities and many differences. These features may help to identify predictive factors in a population in need of adequate diagnosis of and therapy for this long-lasting pathology.

Safety and efficacy of ECT in mental disorders associated with epilepsy: report of three cases.

SUMMARY: The authors report on the use of electroconvulsive therapy (ECT) in the treatment of three patients with mental disorders associated with epilepsy. They discuss several aspects related to safety, efficacy, and indications of ECT in these patients. The observed results, as well as published data, provide evidence that ECT is a safe and effective therapeutic option for some patients with mental disorders associated with epilepsy. The indications are the same as in patients without epilepsy. There might be another possible indication for patients with alternative mental disorders (forced normalization), although improvement after spontaneous seizures may not always predict response to ECT.

Complete remission of epileptic psychosis after temporal lobectomy: case report

We report a case of a female patient with refractory complex partial seizures since 15 years of age, recurrent postictal psychotic episodes since 35 which evolved to a chronic refractory interictal psychosis and MRI with right mesial temporal sclerosis (MTS). After a comprehensive investigation (video-EEG intensive monitoring, interictal and ictal SPECT, and a neuropsychological evaluation including WADA test) she was submitted to a right temporal lobectomy. Since then, she has been seizure-free with remission of psychosis, although with some persistence of personality traits (hiperreligiosity, viscosity) which had been present before surgery. This case supports the idea that temporal lobectomy can be a safe and effective therapeutic measure for patients with MTS, refractory epilepsy and recurrent postictal epileptic psychosis or interictal epileptic psychosis with postictal exacerbation

Functional significance of MRI defined mesial temporal sclerosis in temporal lobe epilepsy

O significado funcional dos sinais de esclerose mesial temporal observados em ressonância magnética ainda näo está estabelecido. Para estudar as relaçöes entre sinais de esclerose mesial temporal na ressonância magnética e alteraçöes no SPECT intercrítico, foram selecionados 18 pacientes com epilepsia do lobo temporal cujo diagnóstico foi definido pela presença de descargas de ondas agudas e alentecimento da atividade de base em vários EEG obtidos durante vários anos de seguimento em todos os pacientes e por registros críticos com eletrodos esfenoidais em 12 pacientes. No grupo 1 foram incluídos pacientes (n=11) com sinais de esclerose mesial temporal na ressonância magnética; no grupo II (n=7), pacientes com ressonância normal. Em todos os casos a injeçäo do Tc99 HMPAO foi realizada no período intercrítico com monitorizaçäo EEG. Foi observada hipoperfusäo lateralizada ipsolateral ao foco definido pelo EEG em 13 pacientes (72 por cento). Todos os pacientes do grupo II e 6 pacientes do grupo I tiveram hipoperfusäo temporal. Este estudo mostrou maior positividade de SPECT em pacientes com ressonância normal do que tem sido referido na literatura. Como os pacientes do grupo II tinham sinais clínicos ou eletrencefalográficos sugestivos de origem neocortical de suas crises epilépticas, postulamos que hipoperfusäo em estudos de SPECT pode ser demonstrada tanto em epilepsia temporal neocortical como mesiolímbica

Esquistossomose mansônica experimental em camundongos submetidos a dieta hipoprotêica

Investigou-se o efeito de dieta moderadamente hipoprotêica (15 g%) de proteínas) sobre o curso de equistossomose mansônica, em camundongos albinos experimentalmente infectados, comparada a dieta normoprotéica (24 g% de proteínas). A dieta hipoprotêica foi administrada a dois grupos de camundongos: desde o desmame e desde a infecçäo por S. mansoni. Determinou-se o índice de letalidade e os pesos corporal, hepático e esplênico nos três grupos de camundongos infectados por S. mansoni (dieta normoprotêica, dieta hipoprotêica desde o desmame e dieta hipoprotêica desde a infecçäo). Determinou-se, também, o comprimento antigido pelos exemplares de S. mansoni, recuperados nos três grupos de camundongos. Os resultados indicaram índice de letalidade significativamente superior entre os grupos de camundongos alimentados com dieta hipoprotêica. Näo foi possível, entretanto, demonstrar a existência de diferenças significativas entre os valores encontrados para os pesos corporal, hepático e esplênico nos três grupos considerados. Também näo se conseguiu evidenciar diferenças significativas com relaçäo ao comprimentodos exemplares de S. mansoni obtidos nos camundongos alimentados com dietas normo e hipoprotêica