Fisiopatología de la enfermedad COVID-19 / Pathophysiology of COVID-19 / Fisiopatologia da doença COVID-19

La enfermedad por coronavirus es una infección respiratoria causada por el virus SARS-CoV 2, el cual genera una cascada de eventos sistémicos, afectando diferentes órganos y tejidos. El entendimiento de la fisiopatología del COVID-19 es indispensable no solo al momento de brindar tratamiento a los pacientes, sino que también para comprender las causas de las complicaciones que presentan un número importante de pacientes recuperados. El objetivo de este trabajo es presentar una revisión actualizada de los efectos de la infección en diferentes órganos y sistemas principales que sea de utilidad como material de referencia para profesionales y estudiantes de la salud. Para ello se realizó una búsqueda bibliográfica en los portales PubMED, Scielo, Google Scholar, Cochrane y Springer Link, así como en las bases de repositorios científicos pre-publicación bioRxiv ("bioarchives") y medRxiv ("med-archives") y sobre un total de cerca de 200 mil artículos, se seleccionaron 100 artículos para esta revisión en base a su relevancia o sugerencias de parte de profesionales especializados.

Coronavirus disease is a respiratory infection caused by the SARS-CoV-2 virus, which causes a cascade of systemic events, affecting various organs and tissues. Understanding the pathophysiology of COVID-19 is essential to treat patients and understand the causes of the complications in a significant number of recovered patients. This article presents a review of the effects of infection on various organs and systems that will be useful as reference material for healthcare professionals and medical students. To this end, a literature search was conducted in PubMED, Scielo, Google Scholar, Cochrane, and Springer Link portals, as well as in the pre-publication scientific repositories bioRxiv ("bioarchives") and medRxiv ("med-archives") databases. From about 200,000 papers, 100 articles were selected for this review based on their relevance or suggestions from experts in the field.

A doença coronavírus é uma infecção respiratória causada pelo vírus SARS-CoV-2, que gera uma cascata de eventos sistêmicos, afetando diferentes órgãos e tecidos. Compreender a fisiopatologia da COVID-19 é essencial não apenas no tratamento de pacientes, mas também para compreender as causas das complicações que um número significativo de pacientes recuperados apresenta. O objetivo deste trabalho é apresentar uma revisão atualizada dos efeitos da infecção em diferentes órgãos e principais sistemas que seja útil como material de referência para profissionais de saúde e estudantes. Para isso, foi realizada uma pesquisa bibliográfica nos portais PubMED, Scielo, Google Scholar, Cochrane e Springer Link, bem como nos repositórios científicos de pré-publicação bioRxiv ("bioarquivos") e medRxiv ("arquivos med"). Num total de cerca de 200 mil artigos, 100 artigos foram selecionados para esta revisão por sua relevância ou sugestões de profissionais especializados.

Narrativa oral de indivíduos com Transtorno do Espectro Alcoólico Fetal / Oral narrative of individuals with Fetal Alcohol Spectrum Disorder

RESUMO Objetivo Investigar e comparar a narrativa oral de indivíduos com Transtorno do Espectro Alcoólico Fetal (TEAF) e de indivíduos com desenvolvimento típico de linguagem (DTL) e correlacionar o desempenho na narrativa oral com a pontuação do "4-Digit Diagnostic Code". Método Participaram 20 indivíduos com TEAF, de ambos os gêneros, com idade cronológica entre seis e 16 anos e 20 indivíduos com DTL, semelhantes quanto ao gênero, idade e nível socioeconômico aos do grupo TEAF. A narrativa oral foi eliciada por meio do livro "Frog, where are you?" e analisada quanto aos aspectos macroestruturais, microestruturais e nível de coerência global. Os aspectos macroestruturais incluíram elementos típicos de história e os microestruturais incluíram palavras (total, palavras diferentes), unidades comunicativas (C-Units), diversidade lexical e extensão média dos C-Units. Resultados Desempenho inferior foi encontrado para o grupo TEAF em todos os aspectos macroestruturais, exceto para os marcadores linguísticos. Dentre os aspectos microestruturais, a diversidade lexical e a ocorrência de "C-Units" incompletos foram aspectos que diferenciaram os grupos TEAF e DTL. O grupo TEAF apresentou nível de coerência global inferior ao grupo DTL. Correlações negativas foram encontradas entre os aspectos macroestruturais e os itens características faciais e alterações no Sistema Nervoso Central. Conclusão O uso restrito de elementos estruturais típicos de história com níveis inferiores de coerência e vocabulário reduzido diferenciaram o TEAF do DTL. Estudos futuros poderão explorar se a associação entre o desempenho narrativo e os itens do "4-Digit Diagnostic Code" apresentam valor preditivo no desempenho narrativo dos indivíduos com TEAF.

ABSTRACT Purpose To investigate and compare the oral narrative of individuals with FASD and individuals with typical language development (TLD), as well as to correlate the narrative performance with the score from 4-Digit Diagnostic Code. Methods Participants were 20 individuals with FASD, of both genders, with chronological age between 6 and 16 years, and 20 individuals with TLD, same gender and similar to the FASD group in age and socioeconomic status. The oral narrative was elicited using the book Frog, where are you? and the data were analyzed in terms of macrostructure, microstructure and global coherence level. Measures regarding the macrostructure included the presence of typical structural elements of storytelling, while the microstructural aspects included words (total and different words), communication units (C-Units), lexical diversity, and mean length of C-Units. Results Low performance was found in the FASD group for all macrostructural aspects, with the exception of linguistic markers. Among the microstructural aspects, lexical diversity and incomplete C-Units were different between the FASD and TLD groups. The FASD group presented lower global coherence level compared to the TLD group. Negative correlations were found between macrostructural aspects, facial characteristics, and Central Nervous System impairment. Conclusion Restricted use of typical structural elements of storytelling with lower levels of coherence and reduced vocabulary distinguished the FASD from the TDL group. Future studies may explore whether the association between narrative performance and the 4-Digit Diagnostic Code items present predictive values in the narrative performance of individuals with FASD.

Bullous pemphigoid and comorbidities: a case-control study in Portuguese patients

BACKGROUND: aAlthough rare, bullous pemphigoid (BP) is the most common autoimmune blistering disease. Recent studies have shown that patients with bullous pemphigoid are more likely to have neurological and psychiatric diseases, particularly prior to the diagnosis of bullous pemphigoid. OBJECTIVE: The aims were: (i) to evaluate the demographic and clinical features of bullous pemphigoid from a database of patients at a Portuguese university hospital and (ii) to compare the prevalence of comorbid conditions before the diagnosis of bullous pemphigoid with a control group. METHODS: Seventy-seven patients with bullous pemphigoid were enrolled in the study. They were compared with 176 age- and gender-matched controls, which also had the same inpatient to outpatient ratio, but no history of bullous or cutaneous malignant disease. Univariate and multivariate analyses were used to calculate odds ratios for specific comorbid diseases. RESULTS: At least one neurologic diagnosis was present in 55.8% of BP patients compared with 20.5% controls (p<0.001). Comparing cases to controls, stroke was seen in 35.1 vs. 6.8%, OR 8.10 (3.80-17.25); dementia in 37.7 vs. 11.9%, OR 5.25 (2.71-10.16); and Parkinson's disease in 5.2 vs. 1.1%, OR 4.91 (0.88-27.44). Using multivariate analysis, all diseases except Parkinson's retained their association with BP. Patients under systemic treatment were eight times more likely to have complications than those treated with topical steroids (p< 0.017). CONCLUSIONS: The results of this study substantiate the association between BP and neurological diseases. In addition, they highlight the potential complications associated with the treatment of BP. .

Organización de las redes cerebrales / Organization of brain networks

El procesamiento de información por el cerebro se basa en sistemas de redes (networks) que poseen propiedades estructurales y funcionales derivadas de su extrema complejidad. Al tratarse de sistemas complejos con propiedades dinámicos no lineares, las redes se auto organizan permanentemente para adecuarse tanto a los procesamientos rápidos, como en el caso de las funciones cognitivas o ejecutivas, como a las más lentas, derivadas de la capacidad de generar cambios plásticos para adaptarse a las situaciones cambiantes de los entornos externos e internos. El estudio de la conectividad en el SNC se ha sistematizado por teorías de gráficas, modelos simples de un sistema, basados en conjuntos de nodos y márgenes o bordes que poseen propiedades de pequeño mundo (ni azarística, ni regular) de modo tal que el conectoma se organiza en los pequeños volúmenes relativos del cerebro permietiendo una alta eficiencia a bajo costo dada la corta distancia ente nodos centrales que procesan gran cantidad de información. Las proyecciones largas entre regiones distantes del SNC si bien eficaces en las funciones integradoras son costosas en estructura y metabolismo, y por ello vulnerables tanto en el desarrollo como en patologías, como la enfermedad de Alzheimer, la esquizofreia, la epilepsia, el ADHD la esclerosis múltiple, etc. Se conceptualiza al conectoma como fenotipo intermedio o endofenotipo con características heredables modificables en las distintas etapas de la vida, desde el desarrollo pre y perinatal hasta el envejecimiento.

The processing of information by the brain is based on systems of networks that have both structural and functional properties, given their extreme complexity. Because they consist in complex systems with nonlinear dynamic properties, the networks organize themselves permanently to adjust either to quick processings, as is the case with cognitive or executive functions and to the slowest processings which result from the capability of generating plastic changes to adapt to the changing contexts of the external and internal environments. The study of connectivity in the CNS has been systematized by graphics theories, which consist in simple models of a system based on sets of nodes and margins or borders that have properties of a small-world network (neither at random nor regular), so that the connectome is organized in the small relative volumes of the brain, enabling a high efficiency at a low cost, given the short distance between central nodes that process a large amount of information. Although the long projections between the regions that are far from the CNS are efficacious in the integrative functions, they are costly in structure and metabolism, and therefore, vulnerable both in development as well as in pathologies such as Alzheimer's Disease, schizophrenia, epilepsy and ADHD in multiple sclerosis, etc. The author conceptualizes the connectome as an intermediate phenotype or endophenotype with modifying inheritable characteristics in the different stages of life, from the pre- and perinatal development until ageing.

Procedimientos endovasculares como tratamiento de la esclerosis múltiple?: la hipótesis de la insuficiencia venosa crónica cerebro medular: [revisión] / Endovascular procedures as multiple sclerosis treatment?: the hipothesis of the chronic cerebrospinal venous insufficiency: [review]

In this "point of view" or special article, it has been reviewed the main bibliographic antecedents related to the entity denominated as chronic cerebrospinal venous insufficiency (CCSVI), which formulation has been stated by Zamboni et col, from the Vascular Diseases Center of the University of Ferrara-Italy, who have assigned it a pathogenic role or of aggravation one in Multiple Sclerosis (MS), what has led them to propose and carry out endovascular balloon angioplasty or venous stent in MS patients as a treatment. The bibliographic review at this stage of the knowledge of CCSVI does not let us to conclude whether this hypothetical entity has any role in the development or aggravation of MS. On the other hand, we agree with most of the clinicians and neuroimaging MS researchers because of the absence of arguments to indicate, support or propose envovascular "therapeutic" procedures for MS. To advance in the knowledge of CCSVI and the eventual relation with MS it is required some multicentric controlled studies carefully led and clinical and methodological rigorous procedures approved by committee of ethic in very well informed patients invited to participate in protocols of formal investigation who should be protected by complementary pertinent insurances and responsibilities connected to the investigation expenses.

En este artículo especial de la modalidad "puntos de vista", se revisan los antecedentes bibliográficos principales relacionados a la entidad denominada "Insuficiencia venosa crónica cerebro medular (IVCCM)" cuya formulación ha sido planteada por Zamboni y col, del Centro de Enfermedades Vasculares de la Universidad de Ferrara-Italia quienes le han adjudicado un rol patogénico o de agravación en la Esclerosis Múltiple (EM), que les ha llevado a proponer y realizar procedimientos de angioplastía mediante balón endovascular o stent venoso en pacientes con EM. La revisión de la bibliografía, en esta etapa del conocimiento de la IVCCM, no permite concluir si esta hipotética entidad tiene algún rol en el desarrollo o agravación de la EM. Por otro lado, concordamos con la mayoría de los clínicos e imagenólogos dedicados al estudio y tratamiento de la EM, en la ausencia de argumentos para indicar, alentar o propiciar procedimientos "terapéuticos" endovasculares para la EM. Para avanzar, en el conocimiento de la IVCCM y de eventual relación con la EM, se requieren estudios multicéntricos cuidadosamente conducidos, clínica y metodológicamente rigurosos, aprobados por comités de ética, en pacientes que sean invitados informadamente a participar en protocolos de investigación formales, que cuenten con las protecciones de seguros complementarios pertinentes y responsabilidades del gasto a costas de los investigadores.

Long-term potentiation and long-term depression: a clinical perspective

Long-term potentiation and long-term depression are enduring changes in synaptic strength, induced by specific patterns of synaptic activity, that have received much attention as cellular models of information storage in the central nervous system. Work in a number of brain regions, from the spinal cord to the cerebral cortex, and in many animal species, ranging from invertebrates to humans, has demonstrated a reliable capacity for chemical synapses to undergo lasting changes in efficacy in response to a variety of induction protocols. In addition to their physiological relevance, long-term potentiation and depression may have important clinical applications. A growing insight into the molecular mechanisms underlying these processes, and technological advances in non-invasive manipulation of brain activity, now puts us at the threshold of harnessing long-term potentiation and depression and other forms of synaptic, cellular and circuit plasticity to manipulate synaptic strength in the human nervous system. Drugs may be used to erase or treat pathological synaptic states and non-invasive stimulation devices may be used to artificially induce synaptic plasticity to ameliorate conditions arising from disrupted synaptic drive. These approaches hold promise for the treatment of a variety of neurological conditions, including neuropathic pain, epilepsy, depression, amblyopia, tinnitus and stroke.

Progress of transcranial magnetic stimulation-motor evoked potential and its forensic application / 法医学杂志

Transcranial magnetic stimulation-motor evoked potential (TMS-MEP) test is one of the electrophysiological examination methods to evaluate the function of central nervous system. The value of the TMS-MEP has been recognized by some clinical forensic workers recently. This article reviews the principle and advantages of TMS-MEP and its application in functional evaluation of central nervous system and clinical treatment. The value of TMS-MEP in forensic medicine, especially in objective assessment of muscle strength after injury of central nervous system is also discussed.

Funciones superiores en pacientes con accidente cerebro vascular / Superior functions in patients with cerebrovascular accidents

Los estudios realizados en Chile hasta la fecha no permiten detectar de manera significativa el deterioro neuropsicológico causado por el accidente cerebro vascular (ACV) y el impacto que éste tiene en el paciente a nivel de su desenvolvimiento diario y familiar. Con base a esto el objetivo de esta investigación fue elaborar un perfil de deterioro neuropsicológico de las diversas funciones cerebrales superiores causado por un ACV, en un grupo de 50 pacientes de la Unidad de Medicina Física del Hospital San José al cuál se le administró un Protocolo de Evaluación Neuropsicológica, comparándose luego con un grupo control de 50 sujetos evaluados con el mismo protocolo. Se encuentra que sobre un 20 por ciento de la población con ACV evaluada presenta deterioro en al menos uno de los ítems evaluados, siendo las funciones ejecutivas, la memoria a largo plazo y la memoria a corto plazo las áreas mayoritariamente afectada en la población evaluada.

The studies in Chile do not allow to detect of significant way the neuropsychological damage caused by the stroke and the impact that this one has in the patient at level of its daily and familiar unfolding. The aim of this research was to elaborate a neuropsychological profile of damage of the diverse superior cerebral functions caused by a stroke. The sample was 50 patients of the Physical Medicine Department from the San José. They was evaluated with a Protocol of Neuropsychological evaluation, comparing itself soon with a group control of 50 subjects evaluated with the same protocol. 20 percent of the evaluated population with stroke displays damage in at least one of the evaluated items, being the executive functions, the long term memory and the short term memory the areas mainly affected in the evaluated population.

Purinergic signalling: past, present and future

The discovery of non-adrenergic, non-cholinergic neurotransmission in the gut and bladder in the early 1960's is described as well as the identification of adenosine 5'-triphosphate (ATP) as a transmitter in these nerves in the early 1970's. The concept of purinergic cotransmission was formulated in 1976 and it is now recognized that ATP is a cotransmitter in all nerves in the peripheral and central nervous systems. Two families of receptors to purines were recognized in 1978, P1 (adenosine) receptors and P2 receptors sensitive to ATP and adenosine diphosphate (ADP). Cloning of these receptors in the early 1990's was a turning point in the acceptance of the purinergic signalling hypothesis and there are currently 4 subtypes of P1 receptors, 7 subtypes of P2X ion channel receptors and 8 subtypes of G protein-coupled receptors. Both short-term purinergic signalling in neurotransmission, neuromodulation and neurosecretion and long-term (trophic) purinergic signalling of cell proliferation, differentiation, motility, death in development and regeneration are recognized. There is now much known about the mechanisms underlying ATP release and extracellular breakdown by ecto-nucleotidases. The recent emphasis on purinergic neuropathology is discussed, including changes in purinergic cotransmission in development and ageing and in bladder diseases and hypertension. The involvement of neuron-glial cell interactions in various diseases of the central nervous system, including neuropathic pain, trauma and ischemia, neurodegenerative diseases, neuropsychiatric disorders and epilepsy are also considered.

Planificación quirúrgica avanzada en neurocirugía: metodología de procesamiento de imágenes integradas / Advanced surgical planning in neurosurgery: methodology of integrated image processing

El riesgo de provocar morbilidad incapacitante y permanente en el paciente neuroquirúrgico ha sido el motor del desarrollo de la imagenología actual. Además de la adquisición de imágenes anatómicas muy detalladas, hoy se puede tener información funcional para cada paciente individual y utilizarla para la planificación del abordaje quirúrgico. La integración de esta información y su utilización racional en un sistema de despliegue tridimensional es el objetivo final de todo el estudio preoperatorio del paciente. La capacidad que tenga el neurocirujano de evaluar esta información antes y durante el acto quirúrgico son determinantes en el resultado. Se analizan la integración de imágenes derivadas de la TAC RM funcional, anatómica y tractografía en la evaluación preoperatoria. A pesar de que la tecnología está ampliamente disponible y al alcance, el conocimiento sobre su empleo correcto para el manejo rutinario no siempre está presente. Actualmente la mayoría de los clínicos deben revisar interminables secuencias de cortes para efectuar una reconstrucción mental del problema del paciente, y con esta información enfrentar el caso. El desafío educacional actual es incorporar el manejo de esta tecnología en la práctica clínica rutinaria, para construir una memoria organizacional que sea capaz de mantener el ritmo de avance que cada vez parece más acelerado.

The risk of incapacitating and permanent morbidity in the neurosurgical patient has driven modern times medical imaging. Besides rich anatomical images, today we can have functional information about the individual patient, to be used in pre-operative planning. The integration of this information for its rational use in a three dimensional planning system is the final goal of all the preoperative study of the patient. The capacity of the neurosurgeon to evaluate and use this information during the actual surgical procedure is determinant in the results. The integration of images from computed tomography, magnetic resonance, anatomic and functional, and lately tractography are analyzed. Although the technology is widely available, knowledge about its use is lacking in the clinical field. Many neurosurgeons still must review hundreds of slices to make a mental composition of the pathology and the anatomy and with this, plan the operation. The challenge is to incorporate this technology in routine clinical practice, to build enough organizational memory to keep pace with the fast rhythm imposed by progress in neuroimaging.

Traumatismo raquimedular / Spinal cord injury

El Traumatismo Raquimedular (TRM) incluye todas las lesiones traumáticas que afectan las diferentes estructuras osteoligamentosas, cartilaginosas, musculares, vasculares, meníngeas, radiculares y medulares de la columna vertebral a cualquiera de sus niveles. Habitualmente afecta a personas jóvenes en etapa productiva. Representa un problema económico para los sistemas de salud dado el alto costo que implica su tratamiento en la etapa aguda y posterior rehabilitación. La medula espinal es el conducto a través del cual viaja la información entre el cerebro y el cuerpo; está diseñada como eje transmisor, regulador y modulador de múltiples funciones neurológicas. La lesión medular aguda es un proceso dinámico, evolutivo y multifásico a partir del momento en que se produce el traumatismo; par ello el objetivo sobre el manejo del daño espinal esta orientado a reducir el déficit neurológico resultante y prevenir alguna pérdida adicional de la función neurológica. El nivel mas frecuente de lesión es la región cervical media baja, el siguiente lugar es la unión toracolumbar; coincidiendo estos niveles con las áreas de mayor movilidad de la columna espinal. En un paciente con sospecha de daño espinal, la columna debe ser inmovilizada para prevenir el daño neurológico y la anatomía de la lesión debe ser analizada como primer paso al memento de proveer un tratamiento efectivo.

O papel das quimiocinas na neuroinflamação / The role of chemokines in neuroinflammation

Inflamação é parte do processo fisiológico que visa reparar o dano tecidual causado por infecção, trauma, isquemia, autoimunidade. Entretanto, quando o processo inflamatório não é controlado, pode contribuir para o aumento da lesão tecidual. A regulação da resposta inflamatória no sistema nervoso central (SNC) envolve diferentes tipos celulares, como neutrófilos, macrófagos e linfócitos, células da glia, moléculas de adesão, citocinas e quimiocinas. As quimiocinas são uma família de citocinas de baixo peso molecular responsáveis pelo recrutamento seletivo de leucócitos, e subdividem-se em quatro subfamílias de acordo com a posição do resíduo cisteína N-terminal dessas moléculas: C, CC, CXC, CX3C. O objetivo desta revisão é apresentar o papel das quimiocinas na regulação da inflamação em doenças do SNC.

Inflammation is part of the physiological process that aims at repairing the tissue damage produced by infection, trauma, ischemia, autoimmune diseases. However, when this process is not controlled, it can increase the tissue lesion. The regulation of the inflammatory response in the central nervous system (CNS) involves different cell types such as neutrophils, macrophages, lymphocytes, glia cells, adhesion molecules, cytokines and chemokines. Chemokines are a large family of low-molecular weight cytokines associated with the selective trafficking of leukocytes, and are classified into four subfamilies on the basis of the arrangement of cysteine residues located in the N-terminal region of these molecules: C, CC, CXC and CX3C. This review will attempt to describe the role of chemokines in the regulation of inflammation in CNS diseases.

A influência das fases oral e faríngea na dinâmica da deglutição / The influence of oral and pharyngeal phases on the swallowing dynamic

RACIONAL: Embora a dinâmica da deglutição ocorra de forma integrada, a fase oral não tem sido tão valorizada quanto a fase faríngea. OBJETIVOS: Avaliar, através do método videofluoroscópico, a fase oral da deglutição, para observar as características da organização do bolo líquido em voluntários sadios e as variações desta organização em exames de pacientes disfágicos. Estabelecer a inter-relação funcional dos estágios de organização e ejeção oral do bolo. Verificar a presença (ou ausência) de interferência do binômio organização/ejeção oral, sobre a fase faríngea da deglutição. CASUíSTICA E MÉTODO: Analisaram-se os exames videofluoroscópicos de 44 indivíduos; destes, 14 eram adultos, voluntários sadios, e 30 disfágicos, sendo 15 pacientes com seqüelas de acidente vascular encefálico e 15 com doença de Parkinson. Todos os indivíduos estudados foram submetidos a avaliação videofluoroscópica da dinâmica da deglutição seguindo protocolo descrito por Junqueira e Costa. Privilegiou-se a incidência em perfil direito com meio de contraste líquido (solução de sulfato de bário). RESULTADOS: Segundo a organização intra-oral do bolo contrastado, pôde-se classificar a organização oral como: fechada, aberta, que pode ser subdividida em anterior e ântero-superior, alongada e instável. A ejeção pode ser definida como: adequada, lentificada e em dois tempos. A correlação entre a dinâmica oral representada pela organização e a dinâmica faríngea pode ser percebida como: adequada, adaptada e alterada. Os diversos tipos de organização e ejeção, assim como as correlações observadas, mostram-se estatisticamente significantes. CONCLUSÕES: A organização do tipo fechada é a que se caracterizou como normal. Organizações aberta ântero-superior, alongada e instável revelam alteração no processo da deglutição. As ejeções dos tipos lentificada e dois tempos também denotam alteração da fisiologia da deglutição. Existe correlação funcional entre os estágios de organização e ejeção oral. A organização oral influiu não só na qualidade da ejeção oral mas também na da dinâmica da fase faríngea.

Symptomatic muscle involvement in neurosarcoidosis: a clinicopathological study of 5 cases

We report on the clinical course and histopathologic muscle alterations of five patients diagnosed with neurosarcoidosis, who underwent biopsy due to their muscle manifestations. The five patients were females and only one was less than 40 years of age. Proximal muscle weakness was presented by all and only two patients complained of myalgia. Only normal values of serum muscle enzymes were detected. Electromyography revealed diverse findings such as normal, myopathic and neuropathic patterns. Granuloma was not present in one muscle biopsy. Two patients thoroughly recovered by taking only prednisone and one patient required a methotrexate addition for 3 months before becoming asymptomatic. The other two patients received azathioprine, one due to steroid side effects but without a satisfactory evolution, and the other to strengthen the prednisone régime, with excellent results

Behaviour of oligodendrocytes and Schwann cells in an experimental model of toxic demyelination of the central nervous system

Oligodendrocytes and Schwann cells are engaged in myelin production, maintenance and repairing respectively in the central nervous system (CNS) and the peripheral nervous system (PNS). Whereas oligodendrocytes act only within the CNS, Schwann cells are able to invade the CNS in order to make new myelin sheaths around demyelinated axons. Both cells have some limitations in their activities, i.e. oligodendrocytes are post-mitotic cells and Schwann cells only get into the CNS in the absence of astrocytes. Ethidium bromide (EB) is a gliotoxic chemical that when injected locally within the CNS, induce demyelination. In the EB model of demyelination, glial cells are destroyed early after intoxication and Schwann cells are free to approach the naked central axons. In normal Wistar rats, regeneration of lost myelin sheaths can be achieved as early as thirteen days after intoxication; in Wistar rats immunosuppressed with cyclophosphamide the process is delayed and in rats administered cyclosporine it may be accelerated. Aiming the enlightening of those complex processes, all events concerning the myelinating cells in an experimental model are herein presented and discussed

Estimulación magnética transcraneana en el hombre / Transcranial magnetic stimulation in man

La estimulación magnética constituye una herramienta de estudio de las vías motoras centrales de carácter no invasivo e indoloro. La ausencia de efectos colaterales y molestias para el paciente han permitido su rápido desarrollo y aceptación. Es posible la estimulación de la corteza motora mediante la estimulación transcraneana (EMT), así como de las raíces motoras a nivel de su pasaje por los agujeros de conjugación mediante la estimulación espinal. Esto permite conocer el tiempo de conducción motora central (TCMC), el parámetro más utilizado, aunque la morfología y la amplitud de las respuestas permite ampliar el espectro diagnóstico. Además del potencial evocado motor (PEM), obtenido como un efecto excitatorio de la EMT, también existe un efecto inhibitorio, conocido como período de silencio (PS). En la esclerosis múltiple es característico el aumento del TCMC debido al retardo en zonas de desmielinización. Pueden observarse también respuestas polifásicas, reducción en la amplitud, aumento en la duración de las respuestas y aun ausencia de éstas. En la mielopatía cervicoartrósica el aumento del TCMC es considerablemente menor que en la anterior, siendo más frecuentes los efectos sobre la amplitud. El estudio de diferentes grupos musculares permite un diagóstico topográfico del nivel de compresión. En el accidente muscular encefálico, la presencia o ausencia de respuestas en los primeros días de instalación permite un pronóstico de recuperación funcional. En la esclerosis lateral amiotrófica se encuentra una marcada reducción de la amplitud y frecuentemente ausencia de respuestas, con escaso o ningún efecto sobre el TCMC

Alteraciones neurotológicas en la esclerosis múltiple / Neurotological distrurbances in multiples sclerosis

La esclerosis múltiple es una enfermedad desmielinizante del sistema nervioso, de etiología aún desconocida. La afección del VIII par craneal es frecuente, por ello se realizó una investigación en 20 pacientes con diagnóstico de certeza de esclerosis múltiple, con manifestaciones otoneurológicas, los cuales fueron sometidos a un examen neurológico, a determinación de inmunoglobulina G en el líquido cefalorraquídeo, audiometría tonal, electronistagmografía, potenciales evocados auditivos del tallo cerebral y resonancia magnética nuclear; con la finalidad de conocer la alteración otoneurológica mas frecuente y el impacto de los estudios paraclínicos en la esclerosis múltiple. El vértigo (90 por ciento) fue el dato mas importante. Los potenciales evocados como la resonancia magnética demostraron la evidencia de lesiones, pero no se pudo establecer una relación entre ambos estudios