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1.
Rheumatology (Oxford) ; 63(2): 456-465, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37216912

RESUMO

OBJECTIVES: To test the association of use of antimalarials with the overall safety of treatment in RA patients receiving one or multiple courses of biologic (b)DMARDs or a Janus kinase inhibitor (JAKi). METHODS: BiobadaBrasil is a multicentric registry-based cohort study of Brazilian patients with rheumatic diseases starting their first bDMARD or JAKi. The present analysis includes RA patients recruited from January 2009 to October 2019, followed up over one or multiple (up to six) courses of treatment (latest date, 19 November 2019). The primary outcome was the incidence of serious adverse events (SAEs). Total and system-specific adverse events (AEs) and treatment interruption served as secondary outcomes. Negative binomial regression with generalized estimating equations (to estimate multivariate incidence rate ratios, mIRR) and frailty Cox proportional hazards models were used for statistical analyses. RESULTS: The number of patients enrolled was 1316 (2335 treatment courses, 6711 patient-years [PY]; 1254.5 PY on antimalarials). The overall incidence of SAEs was 9.2/100 PY. Antimalarials were associated with reduced risk of SAEs (mIRR: 0.49; 95% CI: 0.36, 0.68; P < 0.001), total AEs (0.68; 95% CI: 0.56, 0.81; P < 0.001), serious infections (0.53; 95% CI: 0.34, 0.84; P = 0.007) and total hepatic AEs (0.21; 95% CI: 0.05, 0.85; P = 0.028). Antimalarials were also related to better survival of treatment course (P = 0.003). There was no significant increase in the risk of cardiovascular AEs. CONCLUSION: Among RA patients on treatment with bDMARDs or JAKi, concomitant use of antimalarials was associated with reduced the incidence of serious and total AEs and with longer treatment course survival.


Assuntos
Antimaláricos , Antirreumáticos , Artrite Reumatoide , Produtos Biológicos , Inibidores de Janus Quinases , Humanos , Inibidores de Janus Quinases/efeitos adversos , Antimaláricos/efeitos adversos , Estudos de Coortes , Artrite Reumatoide/epidemiologia , Antirreumáticos/efeitos adversos , Produtos Biológicos/uso terapêutico
2.
Clin Exp Rheumatol ; 35(2): 247-254, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27908303

RESUMO

OBJECTIVES: Neutrophils play a major role in rheumatoid arthritis (RA) pathogenesis. We aimed to evaluate if neutrophil DNA damage in RA patients is associated with the disease activity, autoantibodies status, carriage of the RA shared epitope (SE) and treatment. METHODS: DNA damage was assessed by alkaline comet assay in peripheral blood (77 patients and 55 healthy controls) and in 10 RA synovial fluid neutrophils. Evaluation of the respiratory burst of 30 patients with RA and 30 healthy controls was done. RESULTS: Compared to controls, RA patients exhibited increased neutrophil DNA damage. RA synovial fluid cells DNA damage was increased when compared to OA synovial fluids cells. In addition, our study shows that anti-TNF-α therapy reduces the frequency of DNA damage. Patients with simple or double dose of shared epitope presented a higher frequency of DNA damage compared to patients without the allele. Positive correlation was found between neutrophil DNA damage and DAS-28 and ROS production. CONCLUSIONS: Our results suggest that an increase of respiratory burst of neutrophils reflects the higher levels of DNA damage in neutrophils and a positive correlation between DNA damage and disease activity shows the importance of oxidative stress in the pathogenesis of RA.


Assuntos
Artrite Reumatoide/imunologia , Artrite Reumatoide/patologia , Dano ao DNA , Epitopos/imunologia , Antígenos HLA/imunologia , Neutrófilos/imunologia , Neutrófilos/patologia , Adulto , Antirreumáticos/uso terapêutico , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/metabolismo , Autoanticorpos/sangue , Estudos de Casos e Controles , Ensaio Cometa , Dano ao DNA/efeitos dos fármacos , Epitopos/sangue , Epitopos/genética , Feminino , Antígenos HLA/sangue , Antígenos HLA/genética , Humanos , Pessoa de Meia-Idade , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória , Índice de Gravidade de Doença , Líquido Sinovial/imunologia , Líquido Sinovial/metabolismo , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/imunologia
3.
Inflamm Res ; 61(4): 337-48, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22249931

RESUMO

OBJECTIVE: Endothelins (ETs) are involved in several inflammatory events. The present study investigated the efficacy of bosentan, a dual ETA/ETB receptor antagonist, in collagen-induced arthritis (CIA) in mice. TREATMENT: CIA was induced in DBA/1J mice. Arthritic mice were treated with bosentan (100 mg/kg) once a day, starting from the day when arthritis was clinically detectable. METHODS: CIA progression was assessed by measurements of visual clinical score, paw swelling and hypernociception. Histological changes, neutrophil infiltration and pro-inflammatory cytokines were evaluated in the joints. Gene expression in the lymph nodes of arthritic mice was evaluated by microarray technology. PreproET-1 mRNA expression in the lymph nodes of mice and in peripheral blood mononuclear cells (PBMCs) was evaluated by real-time PCR. The differences were evaluated by one-way ANOVA or Student's t test. RESULTS: Oral treatment with bosentan markedly ameliorated the clinical aspects of CIA (visual clinical score, paw swelling and hyperalgesia). Bosentan treatment also reduced joint damage, leukocyte infiltration and pro-inflammatory cytokine levels (IL-1ß, TNFα and IL-17) in the joint tissues. Changes in gene expression in the lymph nodes of arthritic mice returned to the levels of the control mice after bosentan treatment. PreproET mRNA expression increased in PBMCs from rheumatoid arthritis (RA) patients but returned to basal level in PBMCs from patients under anti-TNF therapy. In-vitro treatment of PBMCs with TNFα upregulated ET system genes. CONCLUSION: These findings indicate that ET receptor antagonists, such as bosentan, might be useful in controlling RA. Moreover, it seems that ET mediation of arthritis is triggered by TNFα.


Assuntos
Artrite Experimental/tratamento farmacológico , Citocinas/metabolismo , Antagonistas dos Receptores de Endotelina , Sulfonamidas/uso terapêutico , Adulto , Animais , Antirreumáticos/uso terapêutico , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/metabolismo , Bosentana , Células Cultivadas , Endotelina-1/genética , Endotelina-1/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Leucócitos Mononucleares , Linfonodos/efeitos dos fármacos , Linfonodos/metabolismo , Masculino , Metotrexato/uso terapêutico , Camundongos , Camundongos Endogâmicos DBA , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/metabolismo
4.
Brain Inj ; 26(1): 95-100, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22149448

RESUMO

BACKGROUND: Ventricular over-drainage is a common complication of dysfunctional ventriculoperitoneal devices. Subdural haematomas are usually the most common lesions associated with that complication. Such lesions may arise after ventricular collapse and bridging veins disruption that follows over-drainage, thus contributing to distortion of brain parenchyma, increased intracranial hypertension and neurological decline. More rarely, extradural haematomas may also be observed after ventricular shunt hyperfunction and may result in rapid neurological decline unless a surgical procedure can be promptly performed. CASE: This study reports the case of a 38-old-woman who presented supratentorial hydrocephalus and developed bilateral extradural haematomas after the placement of a ventricular shunt device. Both haematomas were surgically approached and the dysfunctional shunt device was replaced. CONCLUSION: Extradural haematomas may develop precociously after ventricular over-drainage. Surgical treatment is mandatory and must include not only the evacuation of haematoma, but also the replacement of dysfunctional shunt to prevent further recurrence. The pathophysiology of extradural haematomas consequent of ventricular over-drainage and the possible use of a programmable valve to prevent these lesions are briefly discussed.


Assuntos
Drenagem/efeitos adversos , Hematoma Subdural Intracraniano/etiologia , Hematoma Subdural Intracraniano/cirurgia , Hidrocefalia/cirurgia , Derivação Ventriculoperitoneal/efeitos adversos , Adulto , Remoção de Dispositivo , Feminino , Hematoma Subdural Intracraniano/diagnóstico por imagem , Humanos , Hidrocefalia/complicações , Hidrocefalia/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Resultado do Tratamento
5.
Neurochem Res ; 36(1): 163-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20936504

RESUMO

The neurotoxicity of the amyloid-ß peptide (Aß) appears to be, at least in part, related to pathological activation of glutamate receptors by Aß aggregates. However, the downstream signaling pathways leading to neurodegeneration are still incompletely understood. Hyperactivation of nitric oxide synthase (NOS) and increased nitric oxide (NO) production have been implicated in excitotoxic neuronal damage caused by overactivation of glutamate receptors, and it has been suggested that increased NO levels might also play a role in neurotoxicity in Alzheimer's disease. We have examined the effect of blockade of NO production on the neurotoxicity instigated by Aß42 and by elevated concentrations of glutamate in chick embryo retinal neurons in culture. Results showed that L-nitroarginine methyl ester, a potent inhibitor of all NOS isoforms, had no protective effect against neuronal death induced by either Aß42 (20 µM) or glutamate (1 mM). Surprisingly, at short incubation times both Aß and glutamate decreased NO production in retinal neuronal cultures in the absence of neuronal death. Thus, excitotoxic insults induced by Aß and glutamate cause inhibition rather than activation of NO synthase in retinal neurons, suggesting that cell death induced by Aß or glutamate is not related to increased NO production. On the other hand, considering the role of NO in long term potentiation and synaptic plasticity, the decrease in NO levels instigated by Aß and glutamate suggests a possible mechanism leading to synaptic failure in AD.


Assuntos
Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Óxido Nítrico/metabolismo , Fragmentos de Peptídeos/farmacologia , Retina/citologia , Doença de Alzheimer/metabolismo , Animais , Células Cultivadas , Embrião de Galinha , Inibidores Enzimáticos/farmacologia , Ácido Glutâmico/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Neurônios/citologia , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Nitritos/metabolismo , Sinapses/fisiologia
7.
J Rheumatol ; 48(10): 1519-1527, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33934077

RESUMO

OBJECTIVE: To evaluate the safety of the methotrexate (MTX)-leflunomide (LEF) combination in rheumatoid arthritis (RA), comparing it with other therapeutic schemes involving conventional synthetic (cs-) and biologic (b-) disease-modifying antirheumatic drugs (DMARDs) or Janus kinase inhibitors (JAKi). METHODS: Patients with RA starting a treatment course with a csDMARD (without previous use of bDMARD or JAKi) or their first bDMARD/JAKi were followed up in a registry-based, multicentric cohort study in Brazil (BiobadaBrasil). The primary outcome was the incidence of serious adverse events (SAEs); secondary outcomes included serious infections. Multivariate Cox proportional hazards models and propensity score matching analysis (PSMA) were used for statistical comparisons. RESULTS: In total, 1671 patients (5349 patient-years [PY]) were enrolled; 452 patients (1537 PY) received MTX + LEF. The overall incidence of SAEs was 5.6 per 100 PY. The hazard of SAEs for MTX + LEF was not higher than for MTX or LEF (adjusted HR [aHR] 1.00, 95% CI 0.76-1.31, P = 0.98). MTX + LEF presented a lower hazard of SAEs (aHR 0.56, 95% CI 0.36-0.88, P = 0.01) and infectious SAEs (aHR 0.48, 95% CI 0.25-0.94, P = 0.03) than bDMARDs/JAKi with MTX or LEF. MTX + LEF presented lower hazard of SAEs than MTX + sulfasalazine (SSZ; aHR 0.33, 95% CI 0.16-0.65, P = 0.002). Analysis using PSMA confirmed the results obtained with traditional multivariate Cox analysis. CONCLUSION: In our study, MTX + LEF presented a relatively good overall safety profile in comparison to MTX + SSZ and schemes involving advanced therapies in RA.


Assuntos
Artrite Reumatoide , Metotrexato , Artrite Reumatoide/tratamento farmacológico , Estudos de Coortes , Quimioterapia Combinada , Humanos , Isoxazóis/uso terapêutico , Leflunomida/uso terapêutico , Metotrexato/efeitos adversos , Sistema de Registros
8.
Brain Inj ; 24(7-8): 1039-43, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20515363

RESUMO

BACKGROUND: Chronic subdural haematoma usually arises from a traumatic acute haemorrhage in the subdural space, frequently causing mass effect and consequent neurological decline. This lesion is mainly found over the cortical convexity and its evolution and surgical approach has been extensively studied. Nevertheless, inter-hemispheric chronic subdural haematoma is considered a rare lesion. AIM AND CASE REPORT: This study reported a case of traumatic acute interhemispheric subdural haematoma, initially asymptomatic, and its evolution to a chronic symptomatic lesion, as well as the surgical approach employed. A brief review of the literature is presented with a discussion of the therapeutic options.


Assuntos
Hematoma Subdural/diagnóstico por imagem , Acidentes por Quedas , Doença Crônica , Feminino , Hematoma Subdural/cirurgia , Humanos , Pessoa de Meia-Idade , Prognóstico , Tomografia Computadorizada por Raios X
9.
Adv Rheumatol ; 60(1): 20, 2020 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-32171331

RESUMO

BACKGROUND: In Brazil, socioeconomic differences in the incidence of rheumatoid arthritis (RA) have been demonstrated, which are important in the formulation of hypotheses regarding the association between environmental factors, lifestyle and the risk of disease development. This study examines how the socioeconomic condition of the patient with RA in Brazil, assessed according to social class, educational level, employment situation and use of caregivers, affects the times between the beginning of symptoms and diagnosis and the beginning of the use of disease-modifying antirheumatic drugs, as well as the presence of erosive disease and functional status. METHODS: This work is part of a multicentric study called REAL - Rheumatoid Arthritis in Real Life in Brazil, which is a prospective observational cohort study. RESULTS: As described in the REAL study, we included a total of 1115 patients. It was noted that patients with an educational classification of up to second grade incomplete presented with erosion percentages above those with a higher grade complete. Patients with caregivers presented a higher percentage of erosion than patients without caregivers. We verified that patients from economic classes above B2 presented fewer occurrences of erosion than those from classes C2, D-E. We also analyzed the average time differences from the beginning of symptoms and diagnosis and the beginning of treatment, according to academic level, erosion and economic classification. Patients with first grade complete showed an HAQ-DI averages higher than those with second grade complete. The patients who had employment showed lower HAQ-DI averages than patients who were not employed. The patients with erosion showed an HAQ-DI value higher than those without erosion. Patients with caregivers showed an HAQ-DI average higher than that of without caregivers. CONCLUSION: This study showed that the therapeutic window of RA is not being reached, and therefore we should have a policy to expand and ensure access to public health for all patients, especially those with lower levels of education and income. TRIAL REGISTRATION: This study was approved by the National Commission of Ethics in Research.


Assuntos
Artrite Reumatoide/terapia , Antirreumáticos/uso terapêutico , Artrite Reumatoide/diagnóstico , Brasil , Cuidadores , Estudos de Coortes , Estudos Transversais , Escolaridade , Emprego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Classe Social , Fatores Socioeconômicos
11.
Indian J Nucl Med ; 34(2): 167-168, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31040536

RESUMO

We report a 44-year-old female patient diagnosed with neuropsychiatric systemic lupus erythematosus and probable ischemia secondary to vasculitis in the speech motor region (Broca's area). After corticosteroid treatment, the patient recovered the speech, presented clinical improvement, and SISCOM showed reperfusion of the ischemic area (luxury perfusion).

13.
J Neurosci Methods ; 307: 203-209, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29859877

RESUMO

BACKGROUND: Slice cultures have been prepared from several organs. With respect to the brain, advantages of slice cultures over dissociated cell cultures include maintenance of the cytoarchitecture and neuronal connectivity. Slice cultures from adult human brain have been reported and constitute a promising method to study neurological diseases. Despite this potential, few studies have characterized in detail cell survival and function along time in short-term, free-floating cultures. NEW METHOD: We used tissue from adult human brain cortex from patients undergoing temporal lobectomy to prepare 200 µm-thick slices. Along the period in culture, we evaluated neuronal survival, histological modifications, and neurotransmitter release. The toxicity of Alzheimer's-associated Aß oligomers (AßOs) to cultured slices was also analyzed. RESULTS: Neurons in human brain slices remain viable and neurochemically active for at least four days in vitro, which allowed detection of binding of AßOs. We further found that slices exposed to AßOs presented elevated levels of hyperphosphorylated Tau, a hallmark of Alzheimer's disease. COMPARISON WITH EXISTING METHOD(S): Although slice cultures from adult human brain have been previously prepared, this is the first report to analyze cell viability and neuronal activity in short-term free-floating cultures as a function of days in vitro. CONCLUSIONS: Once surgical tissue is available, the current protocol is easy to perform and produces functional slices from adult human brain. These slice cultures may represent a preferred model for translational studies of neurodegenerative disorders when long term culturing in not required, as in investigations on AßO neurotoxicity.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Neurônios/metabolismo , Neurotransmissores/metabolismo , Adulto , Análise de Variância , Epilepsia do Lobo Temporal/patologia , Feminino , Humanos , Técnicas In Vitro , Masculino , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Fosfopiruvato Hidratase/metabolismo , Cloreto de Potássio/farmacologia , Proteínas tau/metabolismo
14.
Arq Neuropsiquiatr ; 65(4B): 1237-40, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18345438

RESUMO

We report the case of a severe head injured 43-year old male patient with a large extradural hematoma, Glasgow Coma Scale 3 and dilated fixed pupils. Patient was promptly submitted to surgical evacuation of the lesion, but remained in persistent vegetative state in the post-operative time. Head computed tomography scans performed before surgery, and at early and late post-operative periods comparatively revealed extreme bilateral cortical atrophy. Late consequences of severe head trauma drastically affect the prognosis of patients, being its prevention, and neuroprotection against secondary injury still a therapeutical challenge for neurosurgeons.


Assuntos
Córtex Cerebral/patologia , Traumatismos Craniocerebrais/complicações , Hematoma Epidural Craniano/etiologia , Adulto , Atrofia/etiologia , Atrofia/cirurgia , Córtex Cerebral/cirurgia , Traumatismos Craniocerebrais/diagnóstico , Traumatismos Craniocerebrais/cirurgia , Evolução Fatal , Escala de Coma de Glasgow , Hematoma Epidural Craniano/diagnóstico , Hematoma Epidural Craniano/cirurgia , Humanos , Masculino , Tomografia Computadorizada por Raios X
16.
FASEB J ; 18(3): 511-8, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15003996

RESUMO

Alzheimer's disease (AD) and several other neurological disorders have been linked to the overactivation of glutamatergic transmission and excitotoxicity as a common pathway of neuronal injury. The beta-amyloid peptide (Abeta) is centrally related to the pathogenesis of AD, and previous reports have demonstrated that the blockade of glutamate receptors prevents Abeta-induced neuronal death. We show that taurine, a beta-amino acid found at high concentrations in the brain, protects chick retinal neurons in culture against the neurotoxicity of Abeta and glutamate receptor agonists. The protective effect of taurine is not mediated by interaction with glutamate receptors, as demonstrated by binding studies using radiolabeled glutamate receptor ligands. The neuroprotective action of taurine is blocked by picrotoxin, an antagonist of GABA(A) receptors. GABA and the GABA(A) receptor agonists phenobarbital and melatonin also protect neurons against Abeta-induced neurotoxicity. These results suggest that activation of GABA receptors decreases neuronal vulnerability to excitotoxic damage and that pharmacological manipulation of the excitatory and inhibitory neurotransmitter tonus may protect neurons against a variety of insults. GABAergic transmission may represent a promising target for the treatment of AD and other neurological disorders in which excitotoxicity plays a relevant role.


Assuntos
Precursor de Proteína beta-Amiloide/toxicidade , Proteínas do Olho/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Receptores de GABA/efeitos dos fármacos , Receptores de Glutamato/efeitos dos fármacos , Taurina/farmacologia , Doença de Alzheimer/tratamento farmacológico , Animais , Células Cultivadas , Senescência Celular , Embrião de Galinha , Maleato de Dizocilpina/farmacologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Proteínas do Olho/fisiologia , Ácido Glutâmico/farmacologia , Ácido Caínico/toxicidade , N-Metilaspartato/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Picrotoxina/farmacologia , Receptores de AMPA/efeitos dos fármacos , Receptores de GABA/fisiologia , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/fisiologia , Receptores de Glutamato/fisiologia , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Retina/citologia , Retina/embriologia , Taurina/uso terapêutico , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
17.
Int J Biochem Cell Biol ; 36(5): 900-8, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15006642

RESUMO

Accumulation of trehalose has been implicated in the tolerance of yeast cells to several forms of stress, including heat-shock and high ethanol levels. However, yeast lacking trehalase, the enzyme that degrades trehalose, exhibit poor survival after exposure to stress conditions. This suggests that optimal cell viability also depends on the capacity to rapidly degrade the high levels of trehalose that build up under stress. Here, we initially examined the effects of trehalose on the activity of an important antioxidant enzyme, glutathione reductase (GR), from Saccharomyces cerevisiae. At 25 degrees C, GR was inhibited by trehalose in a dose-dependent manner, with 70% inhibition at 1.5M trehalose. The inhibition was practically abolished at 40 degrees C, a temperature that induces a physiological response of trehalose accumulation in yeast. The inhibition of GR by trehalose was additive to the inhibition caused by ethanol, indicating that enzyme function is drastically affected upon ethanol-induced stress. Moreover, two other yeast enzymes, cytosolic pyrophosphatase and glucose 6-phosphate dehydrogenase, showed temperature dependences on inhibition by trehalose that were similar to the temperature dependence of GR inhibition. These results are discussed in terms of the apparent paradox represented by the induction of enzymes involved in both synthesis and degradation of trehalose under stress, and suggest that the persistence of high levels of trehalose after recovery from stress could lead to the inactivation of important yeast enzymes.


Assuntos
Glutationa Redutase/metabolismo , Saccharomyces cerevisiae/enzimologia , Trealose/farmacologia , Betaína/metabolismo , Betaína/farmacologia , Etanol/metabolismo , Glucosefosfato Desidrogenase/efeitos dos fármacos , Glutationa Redutase/efeitos dos fármacos , Temperatura Alta , Pressão Osmótica/efeitos dos fármacos , Dobramento de Proteína , Pirofosfatases/efeitos dos fármacos , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/efeitos dos fármacos , Análise Espectral , Sacarose/metabolismo , Trealose/metabolismo
18.
Neurotox Res ; 5(5): 323-7, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14715451

RESUMO

The beta-amyloid peptide (Abeta) is centrally related to the pathogenesis of Alzheimer's disease (AD). Previous studies have suggested that the neurotoxicity of Abeta may be related to the overactivation of glutamatergic transmission and excitotoxicity, and that blockade of glutamate receptors prevents Abeta-induced cell death. Here, we show that melatonin, a pineal hormone, protects chick retinal neurons in culture against the neurotoxicity of Abeta and glutamate. Right-angle light scattering and thioflavin T fluorescence measurements, as well as light microscopy analysis, indicated that, under our experimental conditions, melatonin had no effect on the aggregation of Abeta. Interestingly, the neuroprotective action of melatonin against the toxicity of Abeta was significantly decreased in the presence of picrotoxin, an antagonist of GABA(A)-like receptors. By itself, picrotoxin had no effect. These results suggest that the neuroprotective effects of melatonin against Abeta neurotoxicity could be at least in part related to a decrease in the excitatory tonus, mediated by activation of GABA receptors and the resulting hyper-polarization of the neurons. Thus, selective pharmacological manipulation of neuronal excitatory/inhibitory tonus could be a potentially interesting new approach in the treatment of AD.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/toxicidade , Antioxidantes/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Ácido Glutâmico/toxicidade , Melatonina/farmacologia , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/toxicidade , Receptores de GABA/efeitos dos fármacos , Animais , Benzotiazóis , Embrião de Galinha , Corantes Fluorescentes , Antagonistas GABAérgicos/farmacologia , Luz , Neurônios/efeitos dos fármacos , Picrotoxina/farmacologia , Retina/citologia , Retina/efeitos dos fármacos , Espalhamento de Radiação , Tiazóis
19.
Arq. bras. neurocir ; 35(4): 319-322, 30/11/2016.
Artigo em Inglês | LILACS | ID: biblio-911044

RESUMO

Introduction Hydrocephalus is a frequent neurological condition in childhood. The most common approach to this disease is still ventricular shunting. However, shunting problems, including catheter infection or shunting malfunctioning, contribute to several complications, such as extra-axial hematomas, which are a possibly lifethreatening. Case report We report the case of a 6-month-old female infant victim of brain trauma. She was previously shunted because of an obstructive hydrocephalus consequent of an aqueductal stenosis diagnosed early after birth. After brain injury, initial symptoms were only irritability and horizontal nystagmus. A computed tomography scan revealed an extra-axial mass lesion that suggested a giant globular extradural hematoma. The patient was submitted to a small exploratory craniectomy to evacuate the blood clot. Surprisingly, the supposed extradural hematoma was, in fact, a chronic subdural hematoma with an unusual shape. After the surgical drainage, the patient remained asymptomatic. No lesion recurrence has been detected so far. Conclusions The case illustrates a very uncommon and interesting presentation of a common neurosurgical disease. A full characterization of the lesion and its pathophysiology is made, and a particular surgical management is proposed and thoroughly discussed


Introdução A hidrocefalia é uma condição neurológica frequente na infância. A abordagem mais comum continua sendo o shunt ventricular. Contudo, os problemas de shunt, incluindo a infecção do catéter ou o mal funcionamento do shunt, contribuem para diversas complicações, como hematomas extra-axiais, uma complicação com potencial comprometimento de vida. Relato de caso Relatamos o caso de uma recém-nascida de 6 meses de idade vítima de trauma cerebral. Ela recebeu previamente um shunt para hidrocefalia obstrutiva consequente de estenose do aqueduto diagnosticada logo após o nascimento. Após o dano cerebral, os sintomas iniciais foram apenas irritabilidade e nistagmo horizontal. Tomografia computadorizada revelou uma massa extra-axial lesionada que sugeriu um hematoma globular extradural gigante. A paciente foi submetida a uma pequena craniectomia exploratória para extração do coágulo sanguíneo. Surpreendentemente, o suposto hematoma extradural era, na verdade, um hematoma subdural crônico com formato anormal. Após drenagem cirúrgica, a paciente permaneceu assintomática. Nenhuma lesão recorrente foi detectada até a presente publicação. Conclusões O caso exemplifica uma apresentação muito incomum e interessante de um distúrbio neurocirúrgico comum. Uma caracterização completa da lesão e de sua patofisiologia é feita, e um procedimento cirúrgico particular é proposto e exaustivamente discutido.


Assuntos
Humanos , Feminino , Lactente , Hematoma Subdural Crônico , Hidrocefalia , Derivação Ventriculoperitoneal , Constrição Patológica , Lesões Encefálicas Traumáticas/complicações
20.
Biophys J ; 85(5): 3255-61, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14581225

RESUMO

The equilibrium unfolding of dimeric yeast glutathione reductase (GR) by guanidine hydrochloride (GdnHCl) was investigated. Unfolding was monitored by a variety of techniques, including intrinsic fluorescence emission, anisotropy and iodide quenching measurements, far-ultraviolet circular dichroism and thiol reactivity measurements. At 1 M GdnHCl, one thiol group of GR became accessible to modification with 5,5'-dithiobis-(2-nitrobenzoic) acid (DTNB), whereas no changes could be detected in the spectroscopic properties (fluorescence, circular dichroism) of the protein. Between 2 and 3 M GdnHCl, two partially folded intermediate states possessing flexible tertiary structures (revealed by fluorescence data) but compact secondary structures (as indicated by circular dichroism measurements) were identified. The quaternary structure of GR in the presence of GdnHCl was also investigated by size-exclusion liquid chromatography. These results indicated the presence of an expanded predissociated dimer at 2.5 M GdnHCl and partially folded monomers at 3 M GdnHCl. Taken together, these results suggest the existence of two molten-globule-like intermediate species (one dimeric and one monomeric) in the unfolding of GR. The results are discussed in terms of the mechanism of GR folding and dimerization.


Assuntos
Glutationa Redutase/química , Guanidina/química , Dicroísmo Circular , Dimerização , Ativação Enzimática , Estabilidade Enzimática , Temperatura Alta , Conformação Proteica , Dobramento de Proteína , Estrutura Secundária de Proteína , Saccharomyces cerevisiae/química , Espectrometria de Fluorescência
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