Abstract Neuropsychiatric or behavioral symptoms of dementia encompass a series of disorders, such as anxiety, depression, apathy, psychosis, and agitation, all commonly present in individuals living with dementia. While they are not required for the diagnosis of Alzheimer's disease (AD), they are ubiquitously present in all stages of the disease, contributing to negative clinical outcomes, including cognitive decline, functional disability, and caregiver burden. Neuropsychiatric symptoms have been conceptualized not only as risk factors but as clinical markers of decline along the AD spectrum. The concept of “mild behavioral impairment”, the behavioral correlate of mild cognitive impairment, has been proposed within this framework. The first steps in the management of behavioral symptoms in AD involve defining the target and investigating potential causes and/or aggravating factors. Once these factors are addressed, non-pharmacological approaches are preferred as first-line interventions. Following the optimization of anticholinesterase treatments, specific pharmacological approaches (e.g., antidepressants, antipsychotics) can be considered weighing potential side effects.

Resumo Sintomas neuropsiquiátricos ou comportamentais de demência envolvem uma série de condições, como ansiedade, depressão, apatia, psicose e agitação, frequentemente observadas em indivíduos com demência. Embora esses sintomas não sejam necessários para o diagnóstico da doença de Alzheimer, estão presentes em todas as fases ou estágios da doença, contribuindo negativamente para o declínio cognitivo, comprometimento funcional e sobrecarga do cuidador. Os sintomas neuropsiquiátricos têm sido conceituados não apenas como fatores de risco, mas também como marcadores clínicos de progressão da doença de Alzheimer. O construto “comprometimento comportamental leve”, correlato comportamental do comprometimento cognitive leve, tem sido proposto nesse contexto. Os primeiros passos na abordagem dos sintomas comportamentais da doença de Alzheimer envolvem definir os alvos-terapêuticos e investigar potenciais causas ou fatores agravantes. Após intervir nesses fatores, abordagens não farmacológicas constituem a primeira linha de intervenção. Depois da otimização do tratamento anticolinesterásico, terapias farmacológicas específicas (por exemplo, antidepressivos, antipsicóticos) podem ser consideradas, levando-se em conta potencias efeitos colaterais.

ABSTRACT Despite substantial progress toward its control, Chagas disease continues to be a major public health problem in Latin America and has become a global health concern. The disease affects approximately 6 million people, of whom 20-40% will develop cardiomyopathy over the years after the initial Trypanosoma cruzi infection. Chagas cardiomyopathy is the most serious and frequent manifestation of Chagas disease. Clinical manifestations vary widely according to the severity of myocardial dysfunction, ranging from asymptomatic to severe forms, including dilated cardiomyopathy with heart failure, arrhythmias, thromboembolism events, and sudden death. Chagas disease is a risk factor for stroke regardless of the severity of cardiomyopathy, which is a leading cause of chronic disability. Classically, stroke etiology in patients with Chagas disease is thought to be cardioembolic and related to apical aneurysm, mural thrombus, and atrial arrhythmias. Although most strokes are thromboembolic, other etiologies have been observed. Small vessel disease, atherosclerosis, and cryptogenic diseases have been reported in patients with Chagas disease and stroke. The potential mechanisms involved in non-embolic strokes include the presence of associated risk factors, pro-inflammatory and prothrombotic disease states, and endothelial dysfunction. However, the contribution of each mechanism to stroke in Chagas disease remains unclear. The review aims to provide an overview of stroke in Chagas disease, highlighting the main pathophysiological mechanisms, clinical presentation, approaches for prevention, and unanswered questions regarding treatment strategies.

RESUMO Estudos investigaram o papel da intervenção nutricional, focada no consumo de alimentos “gatilhos” ou na alteração de peso, na melhora da migrânea. Porém, mudanças na qualidade da dieta ainda não foram abordadas. Objetivo Investigar se intervenção nutricional focada na qualidade da dieta e peso saudável pode melhorar parâmetros clínicos em mulheres com migrânea. Métodos Estudo de intervenção, não controlado e não randomizado. As mulheres receberam plano alimentar individualizado e orientações nutricionais, conforme o diagnóstico nutricional. Dados antropométricos, clínicos e alimentares foram medidos uma vez por mês durante três meses. Recordatório alimentar de 24 horas forneceu informações sobre o consumo alimentar. Qualidade da dieta foi avaliada pelo Índice Brasileiro de Alimentação Saudável (IQD-R). Os questionários Migraine Disability Test (MIDAS) e Headache Impact Test, versão 6 (HIT-6) avaliaram a incapacidade gerada pela enxaqueca e o Inventário de Depressão de Beck (BDI) investigou sintomas depressivos. Resultados Cinquenta e duas mulheres com 44,0 ± 13,0 anos participaram da amostra. Características antropométricas e consumo de energia, macronutrientes e fibras não se alteraram depois da intervenção. No entanto, os escores do IQD-R melhoraram após 60 e 90 dias de intervenção. Os escores do BDI e do HIT-6 diminuíram após 60 e 90 dias, respectivamente. A mudança no escore do IQD-R correlacionou de maneira negativa com a gravidade da enxaqueca avaliada pelo HIT-6 ao final da intervenção. Conclusões O manejo da qualidade da dieta pode ser estratégia para melhorar a gravidade da migrânea, independente do estado nutricional e da mudança de peso dos pacientes.

ABSTRACT Although some studies have investigated the role of nutritional intervention on migraine, they had focused on triggers or on weight change and, to the best of our knowledge, none studied diet quality. Objective To investigate whether nutritional intervention focused on improving diet quality and healthy weight can promote improvement in clinical parameters of women with migraine. Methods Non-controlled and non-randomized intervention study conducted for 90 days. Women received an individualized diet meal plan and nutritional orientation according to their nutritional diagnosis. Anthropometric, clinical and nutritional data were measured once a month. Diet energy content and macronutrients were evaluated using 24-hour dietary recall. Diet quality was assessed through the Brazilian Healthy Eating Index–Revised (BHEI-R). The Migraine Disability Assessment and Headache Impact Test version 6 were used to assess the severity of migraine, and the Beck Depression Inventory evaluated depressive symptoms. Results Fifty-two women aged 44.0 ± 13.0 years were enrolled. Anthropometric characteristics, energy, macronutrients and fiber intake did not change after intervention. However, the BHEI-R scores improved after 60 and 90 days of intervention. Concurrent to this, the Beck Depression Inventory scores and Headache Impact Test scores decreased after 60 and 90 days, respectively. The change in the BHEI-R score was negatively correlated with the migraine severity as assessed by the Headache Impact Test at the end of the intervention. Conclusions We concluded that the management of diet quality may be a good strategy for improving migraine severity, regardless of the nutritional status and weight change.

RESUMO Há evidências de que alteracões nas ações exercidas por fatores neurotróficos (FNs) estejam associadas à fisiopatologia da doença de Parkinson (DP). O presente estudo foi conduzido para avaliar os níveis plasmáticos de FNs e suas possíveis associações com sintomas clínicos na DP. Para este fim, 40 pacientes com DP e 25 controles foram submetidos à avaliação clínica e coleta de sangue periférico. Os níveis plasmáticos do fator neurotrófico derivado do cérebro (BDNF), pro-BDNF, neurotrofina 3, neurotrofina 4, fator de crescimento do nervo, fator neurotrófico derivado da glia e fator neurotrófico ciliar foram avaliados por ensaio de imunoadsorção enzimática. Não houve diferença significativa entre pacientes com DP e controles quanto aos níveis plasmáticos dos FNs avaliados. Além disso, não encontramos associação entre os níveis dos FNs e duração da doença, grau de comprometimento motor ou funcional, desempenho cognitivo e gravidade dos sintomas depressivos. Em conclusão, embora os FNs possam desempenhar papéis relevantes na fisiopatologia da DP, os níveis circulantes dessas moléculas não estão necessariamente alterados em pacientes com DP.

ABSTRACT There is great evidence linking neurotrophic factor (NF) dysfunction with Parkinson's disease (PD) pathophysiology. This study was conducted to evaluate plasma levels of NFs and their possible associations with clinical symptoms in PD. For this purpose, 40 PD patients and 25 controls were subjected to a clinical evaluation and peripheral blood draw. Plasma levels of brain-derived neurotrophic factor (BDNF), pro-BDNF, neurotrophin 3, neurotrophin 4, nerve growth, glial cell line-derived neurotrophic factor and ciliary neurotrophic factor were measured by enzyme-linked immunosorbent assay. There was no significant difference between PD patients and controls regarding the plasma levels of the evaluated NFs. In addition, NF levels were not associated with disease duration, degree of motor or functional impairment, cognitive performance or severity of depressive symptoms. In conclusion, although NFs may play relevant roles in the pathophysiology of PD, the circulating levels of these molecules are not necessarily changed in patients with PD.

Abstract Toxoplasmic retinochoroiditis (TR) is the most common identifiable cause of posterior uveitis in Brazil. Response to treatment and clinical presentation may vary significantly. We assessed serum levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurotrophin (NT)-3, and NT-4/5 in patients with active TR, before and after TR treatment. Methods: Twenty patients with active lesion and 15 healthy controls were enrolled in the study. Serum concentration of neurotrophic factors was determined by enzyme-linked immunosorbent assay. Results: BDNF levels were significantly higher in patients before treatment when compared with controls (p = 0.0015). There was no significant difference in pro-BDNF, NGF, GDNF, NT-3, and NT-4/5 levels between TR patients and controls. Treatment did not affect the levels of these factors. Conclusion: BDNF may be released in the context of the active TR inflammatory response.

RESUMO Neste estudo prospectivo foi avaliada a influência do polimorfismo -351A/G XbaI do gene do receptor de estrogênio alfa (ESR-1) sobre o desempenho cognitivo global em idosos muito idosos (≥ 75 anos) saudáveis durante um ano. Métodos Os indivíduos foram divididos em dois grupos de acordo com a presença ou ausência de declínio cognitivo. Dados cognitivos foram relacionados à informação genética. Resultados O genótipo XbaI -351 AA foi mais comum entre indivíduos que apresentaram declínio cognitivo, enquanto carreadores do alelo -351G demonstraram estabilidade ou melhora cognitiva. Conclusão Estes resultados sugerem que ESR-1 poderia estar associado ao declínio cognitivo em curto prazo em idosos saudáveis, possivelmente por meio de propriedades neuroprotetoras do estrogênio, mesmo em cérebros idosos saudáveis.

ABSTRACT This prospective study aimed to evaluate the influence of the -351A/G XbaI polymorphism in the estrogen receptor-alpha (ESR-1) gene on global cognitive scores of a community sample of healthy oldest-old individuals within one year of follow up. Methods The individuals were categorized in two groups according to the presence or absence of cognitive decline. Cognitive data were related to genetic information. Results The XbaI -351 AA genotype was more common among cognitive decliners, while -351G allele carriers showed cognitive stability or improvement. Conclusion These results suggest that ESR-1 could be associated with one-year cognitive decline in healthy oldest-old individuals, since the estrogen pathway may be involved with neuroprotection, even in healthy brain aging.

RESUMO A doença de Huntington (DH) é uma doença neurodegenerativa autossômica dominante classificada entre as coreias. Além de sintomas motores, a DH é caracterizada por sintomas cognitivos e comportamentais que impactam na capacidade funcional dos pacientes. A progressão dos sintomas neuropsiquiátricos e déficits cognitivos ocorre paralelamente à neurodegeneração. A natureza desses sintomas é muito dinâmica, sendo que os desafios clínicos mais comuns incluem disfunção executiva, apatia, depressão e irritabilidade. O presente artigo apresenta uma revisão atualizada sobre as manifestações cognitivas e psiquiátricas da DH.

ABSTRACT Huntington's disease (HD) is an autosomal dominant neurodegenerative disease classified under the choreas. Besides motor symptoms, HD is marked by cognitive and behavioral symptoms, impacting patients' functional capacity. The progression of cognitive impairment and neuropsychiatric symptoms occur in parallel with neurodegeneration. The nature of these symptoms is very dynamic, and the major clinical challenges include executive dysfunction, apathy, depression and irritability. Herein, we provide a focused updated review on the cognitive and psychiatric features of HD.

OBJECTIVES: The aims of the current study were 1) to evaluate the reliability and validity of the Brazilian version of the 15-item Myasthenia Gravis Quality of Life Scale and 2) to investigate the quality of life of Brazilian patients with myasthenia gravis and its determinants. METHODS: This cross-sectional study included 69 patients with myasthenia gravis who underwent neurological evaluation and completed questionnaires regarding quality of life (the 36-item Short Form of the Medical Outcomes Study and the 15-item Myasthenia Gravis Quality of Life Scale), anxiety and depressive symptoms. RESULTS: The Brazilian version of the 15-item Myasthenia Gravis Quality of Life Scale showed high internal consistency and good concurrent validity with the 36-item Short Form of the Medical Outcomes Study and its subscales. Determinants of quality of life in Brazilian patients with myasthenia gravis included the current status of myasthenia gravis as assessed by the Myasthenia Gravis Composite, the current prednisone dose and the levels of anxiety and depression. CONCLUSION: The Brazilian version of the 15-item Myasthenia Gravis Quality of Life Scale is a valid instrument. Symptom severity, prednisone dosage and anxiety and depression levels impact the quality of life of patients with myasthenia gravis.

Os mecanismos subjacentes aos sintomas da coreia de Sydenham (CS) permanecem desconhecidos. Considerando-se a hipótese de que a patogênese da CS é mediada por anticorpos autorreativos, a persistência da coreia está provavelmente associada a níveis aumentados de linfócitos B1 e outros subtipos de linfócitos. No presente trabalho, foram avaliados subtipos de linfócitos B e T em pacientes com CS em remissão (CSR) e persistente (CSP), por citometria de fluxo. Nossos resultados demonstraram que não há diferença na frequência das subpopulações de linfócitos T e B circulantes e no perfil de ativação e estado funcional dessas células. Esses resultados enfraquecem a hipótese de que a CSP seja uma condição imune sustentada mediada por células citotóxicas. São necessários estudos que investiguem mecanismos alternativos que expliquem a patogênese da CSP.

The mechanisms involved in the symptoms of Sydenham’s chorea (SC) remain obscure. Taking into account the autoreactive antibody-mediated hypothesis of SC pathogenesis, the persistence of chorea may be associated with increased levels of B1 lymphocytes and other lymphocyte subsets. We evaluated lymphocyte subsets, including B1 and T cells, in patients with remitted (RSC) and persistent (PSC) SC by flow cytometry. Our results showed neither difference in the frequency of T and B lymphocytes subpopulations nor in their activation and functional states. These findings undermine the view of PSC as a sustained cytotoxic cellular-mediated condition. Alternative mechanisms may explain the pathogenesis of PSC.

RESUMO Um alcance educacional mais elevado constitui um fator protetivo contra o declínio cognitivo em idosos. Todavia, os elementos subjacentes a esta associação ainda são pouco compreendidos. Objetivo: O principal objetivo deste estudo foi comparar indivíduos analfabetos com comprometimento cognitivo com analfabetos cognitivamente normais, de acordo com aspectos demográficos, morbidades, hábitos de vida e genótipo APOE. Métodos: Este é um estudo transversal da amostra de participantes analfabetos (n=174) do Estudo Pietà, um levantamento de base comunitária sobre envelhecimento cerebral bem sucedido, conduzido em Caeté (MG), Brasil. Os sujeitos foram categorizados em três grupos diagnósticos: cognitivamente normais, comprometimento cognitivo não demência e demência. Os grupos foram então comparados conforme variáveis selecionadas. Resultados: Indivíduos com demência eram mais idosos e apresentaram uma maior prevalência de relato de acidente vascular encefálico ou ataque isquêmico transitório. Os três grupos não se mostraram diferentes em relação à demografia, prevalência de comorbidades, nível socioeconômico, perfil ocupacional prévio e frequência do alelo APOE-e4. A avaliação qualitativa de hábitos de vida, como o consumo de bebida alcoólica, fumo e engajamento em atividade física também foi semelhante entre os grupos. Conclusão: Não encontramos associações entre comprometimento cognitivo/demência e as variáveis investigadas nesta amostra comunitária de idosos analfabetos.

ABSTRACT A higher level of educational attainment constitutes a protective factor against cognitive decline in the elderly. Nevertheless, the elements underpinning this association are yet not fully understood. Objective: The primary aim of this study was to compare cognitively impaired illiterate elderly subjects with cognitively preserved counterparts, according to demographics, comorbidities, lifetime habits and APOE genotype. Methods: This is a cross-sectional analysis of the illiterate subset of participants (n=174) from the Pietà study, a community-based survey of successful brain aging conducted in Caeté (MG), Brazil. Subjects were categorized into three diagnostic groups: cognitively normal (CN), cognitive impairment no-dementia (CIND) and dementia. The groups were then compared according to selected variables. Results: Subjects with dementia were older and had an increased prevalence of reported stroke or transient ischemic attack. The three groups did not differ in relation to demographics, prevalence of comorbidities, socioeconomic level, previous occupation profile and APOE-e4 allele frequency. Qualitatively evaluated lifetime habits, such as alcohol consumption, smoking and physical activity engagement were also similar across groups. Conclusion: No associations were found between cognitive impairment/dementia and the variables evaluated in this community-based sample of illiterate elderly.

Leprosy is an infectious and contagious spectral disease accompanied by a series of immunological events triggered by the host response to the aetiologic agent, Mycobacterium leprae . The induction and maintenance of the immune/inflammatory response in leprosy are linked to multiple cell interactions and soluble factors, primarily through the action of cytokines. The purpose of the present study was to evaluate the serum levels of tumour necrosis factor (TNF)-α and its soluble receptors (sTNF-R1 and sTNF-R2) in leprosy patients at different stages of multidrug treatment (MDT) in comparison with non-infected individuals and to determine their role as putative biomarkers of the severity of leprosy or the treatment response. ELISA was used to measure the levels of these molecules in 30 healthy controls and 37 leprosy patients at the time of diagnosis and during and after MDT. Our results showed increases in the serum levels of TNF-α and sTNF-R2 in infected individuals in comparison with controls. The levels of TNF-α, but not sTNF-R2, decreased with treatment. The current results corroborate previous reports of elevated serum levels of TNF-α in leprosy and suggest a role for sTNF-R2 in the control of this cytokine during MDT.

Objetivo Realizar a tradução e a adaptação transcultural do “Questionário de Qualidade de Vida Específico para Miastenia Gravis – 15 itens” (MG-QOL15). Método Inicialmente, foi realizada a tradução do instrumento original em inglês para o português. Esta versão foi revisada e retrotraduzida para o inglês. A versão retrotraduzida foi comparada à versão original em inglês, sendo corrigidas as divergências no texto em português. Em um segundo momento, dez pacientes com MG acompanhados na Clínica de Doenças Neuromusculares do Hospital das Clínicas da Universidade Federal de Minas Gerais responderam ao questionário. Na aplicação do questionário, os itens mal compreendidos foram analisados pelos autores. Resultados Os itens 8, 13 e 15 foram considerados de difícil compreensão e modificados na versão final em português. A maioria dos pacientes (70%) apresentou uma pontuação total superior a 25, sendo que os itens 3, 8 e 9 apresentaram os escores mais elevados. Conclusão A versão brasileira do MG-QOL15 é um instrumento promissor para a avaliação de pacientes brasileiros com MG.

Objective To translate and to perform the cross-cultural adaptation of the “Questionnaire of Life Quality Specific for Myasthenia Gravis - 15 items” (MG-QOL15). Method The original English version of the questionnaire was translated into Portuguese. This version was revised and translated back into English. Later, both English versions were compared and the divergences were corrected in the Portuguese text. At a second stage, ten patients with MG followed at the Neuromuscular Diseases Clinic from the University Hospital, Universidade Federal de Minas Gerais answered the questionnaire. The authors analyzed the difficulties and misunderstandings in the application of the questionnaire. Results The questions 8, 13 and 15 were considered difficult to understand and were modified in the final Portuguese version. Most patients (70%) had a total score above 25, and the statements 3, 8 and 9 showed the highest scores. Conclusion The Brazilian version of the questionnaire MG-QOL15 seems to be a promising tool for the assessment of Brazilian patients with MG.

RESUMO Apatia está intimamente associada à demência. Lamentavelmente, sua fisiopatologia ainda é pouco compreendida. O comprometimento motivacional que caracteriza este transtorno poderia compartilhar mecanismos inflamatórios como sugere a teoria do comportamento associado à doença. Objetivo: O principal objetivo deste estudo foi investigar a associação entre apatia e os níveis séricos do fator de necrose tumoral alfa (TNF-α) e de seus receptores solúveis. Os níveis de fator neurotrófico derivado do cérebro também foram analisados já que estes foram associados à depressão, que compartilha aspectos abúlicos com a apatia. Métodos: A amostra consistiu de 27 indivíduos com doença de Alzheimer leve ou com comprometimento cognitivo leve amnéstico, que foram submetidos à avaliação de apatia pela Escala de Apatia (EA), e proveram amostra de sangue para análise de biomarcadores. De acordo com a mediana de escores na EA (17 pontos), a amostra foi divida em dois grupos. Resultados: O grupo com mais sintomas de apatia apresentou maiores níveis séricos de receptores solúveis de TNF-α (tipo 1: p=0,03 ; tipo 2: p=0,04). Nenhuma outra diferença foi encontrada entre os grupos. Conclusão: Estes achados sugerem o envolvimento de mediadores inflamatórios na gênese de sintomas de apatia, assim como sugere a teoria do comportamento associado à doença.

ABSTRACT Apathy is intimately associated with dementia. Unfortunately, its pathophysiology remains poorly understood. The motivational impairment that characterizes this disorder might share the same inflammatory mechanisms, as suggested by the sickness behavior theory. Objective: The primary aim of this study was to investigate the association between apathy symptoms and serum levels of tumor necrosis factor alpha (TNF-α) and its soluble receptors. Brain-derived neurotrophic factor (BDNF) levels were also analyzed since these have been associated with depression, a condition which shares abulic features with apathy. Methods: The sample consisted of 27 subjects with mild Alzheimer's disease or amnestic mild cognitive impairment, who were submitted to specific apathy evaluation using the Apathy Scale (AS) and provided blood samples for biomarker analysis. Participants were categorized into two groups according to median AS scores (17 points). Results: Subjects with higher apathy symptoms (n=13) displayed higher levels of TNF-α soluble receptors (type 1: p=0.03; type 2: p=0.04). No other difference was found between groups. Conclusion: These findings point to the involvement of inflammatory mediators in the genesis of apathy symptoms, as suggested by the sickness behavior theory.

The prevalence of neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), increases with age, and the number of affected patients is expected to increase worldwide in the next decades. Accurately understanding the etiopathogenic mechanisms of these diseases is a crucial step for developing disease-modifying drugs able to preclude their emergence or at least slow their progression. Animal models contribute to increase the knowledge on the pathophysiology of neurodegenerative diseases. These models reproduce different aspects of a given disease, as well as the histopathological lesions and its main symptoms. The purpose of this review is to present the main animal models for AD, PD, and Huntington's disease.

OBJECTIVE: Ischemic stroke may result from transient or permanent reductions of regional cerebral blood flow. Polymorphonuclear neutrophils have been described as the earliest inflammatory cells to arrive in ischemic tissue. CXCR1/2 receptors are involved in the recruitment of these cells. However, the contribution of these chemokine receptors during transient brain ischemia in mice remains poorly understood. In this work, we investigated the effects of reparixin, an allosteric antagonist of CXCR1/2 receptors, in a model of middle cerebral artery occlusion and reperfusion in mice. METHODS: C57BL/6J male mice treated with reparixin or vehicle were subjected to a middle cerebral artery occlusion procedure 1 h after the treatment. Ninety minutes after ischemia induction, the monofilament that prevented blood flow was removed. Twenty-four hours after the reperfusion procedure, behavioral changes, including motor signs, were analyzed with the SmithKline/Harwell/lmperial College/Royal Hospital/Phenotype Assessment (SHIRPA) battery. The animals were sacrificed, and brain tissue was removed for histological and biochemical analyses. Histological sections were stained with hematoxylin and eosin, neutrophil infiltration was estimated by myeloperoxidase activity and the inflammatory cytokine IL-iβ was measured by ELISA. RESULTS: Pre-treatment with reparixin reduced the motor deficits observed in this model of ischemia and reperfusion. Myeloperoxidase activity and IL-iβ were reduced in the reparixin-treated group. Histological analysis revealed that ischemic injury was also attenuated by reparixin pre-treatment. CONCLUSIONS: Our results suggest that the blockade of the CXCR1/2 receptors by reparixin promotes neuroprotective effects by reducing the levels of polymorphonuclear infiltration in the brain and the tissue damage associated with middle cerebral artery occlusion and reperfusion.