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1.
J Phys Chem B ; 123(37): 7905-7918, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31433179

RESUMO

Glasses Al2/3O-TeO2, ZnO-TeO2 and R2/3O-ZnO-TeO2 (R = Al, B) were prepared by melting in Pt crucibles and studied for correlations between structure and thermal as well as mechanical properties, whereby the glass composition is varied to tailor the short-range speciation of tellurite, aluminate, and borate groups. The glass structure was studied by Raman and infrared spectroscopy analyses, and the measured properties include glass-transition temperature (Tg), density (ρ), and ultrasonic longitudinal (VL) and transverse (VT) velocities. In addition, atomic packing density (Cg), elastic moduli, and Poisson's ratio (σ) were evaluated from the measured properties. It was found that Al2/3O leads to cross-linked alumino-tellurite networks by strong Te-O-Al bonds, which cause a profound enhancement in Tg. The influence of ZnO and B2/3O on Tg is relatively smaller due to the weaker cross-linking effects of ZnO4 tetrahedra and of Te···O-B bonds. Short-range bonding characteristics, interatomic bonding energy differences, and atomic packing density were found to have a strong effect on VT and mostly on the VL sound velocity. The combined effects of structure and bonding are nicely expressed in the composition dependence of Poisson's ratio; it exhibits decreasing trends with Al2/3O content in the binary and ternary glasses studied here, but increasing trends with ZnO and B2/3O additions in glasses ZnO-TeO2 and B2/3O-ZnO-TeO2, respectively. The results for Poisson's ratio and atomic packing density for the studied glasses were found to fit nicely in the global σ versus Cg correlation established previously for a range of glasses not including tellurites so far. Finally, the sound velocities and Poisson's ratio of pure TeO2 glass were determined for the first time and found to differ markedly from those in the literature for TeO2 glass melted in alumina crucible; this is because the latter glass is highly doped by Al2O3 leached from the alumina crucible.

2.
Acta Neurol Scand ; 137(1): 142-148, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28948600

RESUMO

OBJECTIVE: We performed a systematic review and meta-analysis to evaluate the proposed association of restless legs syndrome (RLS) with cerebrovascular/cardiovascular outcomes. METHODS: We calculated the corresponding odds ratios on the prevalence of cerebrovascular/cardiovascular risk factors and standardized mean differences on the reported mean age at baseline between RLS patients and controls. We also calculated the corresponding risk ratios and adjusted for potential confounders hazard ratios (HRsadjusted ) on the reported outcomes of interest between RLS patients and controls. RESULTS: We identified 8 eligible studies (644 506 patients, mean age: 60.2 years, 36.2% males; 3.3% with RLS). RLS patients were found to have significantly higher prevalence of hypertension (P = .002), diabetes (P = .003) and hyperlipidemia (P = .010) compared to controls. In the unadjusted analyses of prospective observational studies, RLS patients were found to have significantly higher risk for cerebrovascular ischaemia (P = .01) and all-cause mortality (P = .04) compared to controls during follow-up, while in the adjusted for potential confounders analyses RLS patients were only found to have a higher risk of all-cause mortality (HR adjusted=1.52, 95% CI: 1.17-1.97, P = .002). CONCLUSIONS: The present report does not provide evidence for an increased risk of cerebrovascular and cardiovascular events in RLS patients, which highlights the vast presence of confounding factors.


Assuntos
Doenças Cardiovasculares/epidemiologia , Transtornos Cerebrovasculares/epidemiologia , Síndrome das Pernas Inquietas/epidemiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco
3.
Eur J Neurol ; 23(3): 569-79, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26918744

RESUMO

BACKGROUND AND PURPOSE: The diagnostic utility of transesophageal echocardiography (TEE) in patients with cryptogenic ischaemic stroke (IS) or transient ischaemic attack (TIA) remains controversial. METHODS: A systematic review and meta-analysis was performed according to PRISMA guidelines to estimate the pooled prevalence of potential cardioembolic causes detected by TEE in prospective observational studies of cryptogenic IS/TIA. Cardiac conditions causally associated with cerebral ischaemia were considered to be intramural thrombi and intracardiac tumors according to ASCO phenotyping of IS. RESULTS: Thirty-five eligible studies, comprising 5772 patients (mean age 53.6 years, 56.9% men) were identified. The most common TEE finding was ascending aorta and/or aortic arch atheroma [51.2% (27.4%-74.5%)], followed by patent foramen ovale (PFO) [43.2% (36.3%-50.4%)]. Complex aortic plaques and large PFOs were reported in 14% (10.2%-18.9%) and 19.5% (16.6%-22.8%) of TEE evaluations. The prevalence of atrial septal aneurysm was 12.3% (7.9%-18.7%) and was significantly higher in conjunction with PFO presence (risk ratio 2.04, 95% confidence interval 1.63-2.54, P < 0.001). The prevalence of left atrial thrombus [3.0% (1.1%-8.3%)] and spontaneous echo contrast [3.8% (2.3%-6.2%)] was low. The prevalence of intracardiac tumors was extremely uncommon [0.2% (0%-0.7%)]. Significant heterogeneity was identified (I(2) > 60%) in the majority of analyses. Heterogeneity was not affected by cryptogenic stroke definition (TOAST versus alternative criteria). After dichotomizing available studies using a cut-off of 50 years, PFO was significantly (P = 0.001) more prevalent in younger than in older patients. CONCLUSION: Routine TEE in patients with cryptogenic IS/TIA commonly identifies abnormal findings. However, the prevalence of cardiac conditions considered to be causally associated with cerebral ischaemia (intracardiac thrombi and tumors) is low.


Assuntos
Isquemia Encefálica/etiologia , Ecocardiografia Transesofagiana/estatística & dados numéricos , Cardiopatias/diagnóstico , Acidente Vascular Cerebral/etiologia , Feminino , Cardiopatias/complicações , Humanos , Ataque Isquêmico Transitório/etiologia , Masculino , Pessoa de Meia-Idade
4.
Carbohydr Polym ; 133: 110-6, 2015 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-26344262

RESUMO

Water absorption in chitosan rapidly increases when the deacetylation degree decreases between 85 and 45%. This seems to contradict the fact that water absorption in chitin is much lower than that of chitosan. The aim of this paper is to understand this feature by measuring the main parameters affecting equilibrium water content. Since swelling capacity depends on the water-polymer interaction, the Flory Huggins interaction parameter was evaluated, finding small or null dependence on the deacetylation degree. Other factor influencing elastic energy is chain stiffness related to the elastic modulus that was measured as a function of deacetylation degree. Besides, crystalline structure was measured by X-ray diffraction patterns as a characteristic of cross-linking density. These observations led us to conclude that the instability of crystals during the swelling process increases with decreasing deacetylation degree, explaining the high equilibrium water content of low deacetylation chitosans.


Assuntos
Quitosana/química , Nitrogênio/química , Água/química , Absorção Fisico-Química , Acetilação , Fenômenos Mecânicos , Volatilização
5.
Eur J Neurol ; 21(8): 1083-1088, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24471738

RESUMO

BACKGROUND AND PURPOSE: Apolipropotein E(apoE) is a plasma protein exhibiting three common isoforms (E2, E3, E4). Its involvement in lipoprotein metabolism may have an impact on stroke occurrence. As results in the literature are inconclusive further studies are needed to elucidate its role. Our objective was to study the role of apoE isoforms and the interplay with environmental risk factors in patients with first ischaemic stroke occurrence in the Greek population. METHODS: Three hundred and twenty-nine patients with first-ever ischaemic stroke were included in our study. Strokes of cardioembolic origin and patients with autoimmune or prothrombotic syndromes were excluded. A control group of 361 subjects with no stroke history were also included in our study. Risk factors (hyperlipidemia, hypertension, diabetes mellitus and smoking) were assessed. ApoE alleles were determined in all subjects participating in the study. RESULTS: Genotype ε3/ε3 was found to have a protective role against stroke occurrence compared with other genotypes (odds ratio 0.674, 95% confidence interval 0.480-0.946) especially in the female patient subgroup. In multivariate analysis after adjustment for age, body mass index (BMI), hypertension, dyslipidemia, diabetes mellitus and smoking, the role of genotype was limited and outweighed by risk factors in both genders. No association between apoE alleles and BMI, cholesterol, triglycerides or high-density lipoprotein plasma levels was noted. CONCLUSIONS: Our study was indicative of a protective role of the ε3/ε3 genotype, especially in female patients. However, risk factors such as age, BMI, hypertension, dyslipidemia, diabetes mellitus and smoking have a strong impact on stroke occurrence and outweigh the protective role of the ε3/ε3 genotype.


Assuntos
Apolipoproteína E3/genética , Isquemia Encefálica/genética , Acidente Vascular Cerebral/genética , Idoso , Feminino , Genótipo , Grécia , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo Genético , Fatores de Proteção , Fatores de Risco , Fatores Sexuais
6.
Phlebology ; 29(1): 52-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23155130

RESUMO

OBJECTIVES: To examine and compare the effects of downwards versus upwards total stripping of great saphenous vein (GSV) on saphenous nerve (SN) injury using clinical and electrophysiological studies. METHODS: Fifty patients with varicosities were equally and randomly assigned to undergo total, upwards stripping (group A) or downwards stripping (group B) of GSV during saphenectomy. SN function was measured with electroneurogram (ENG) before operation, two weeks and 12 weeks after, in order to record the incidence and type of SN injury. Clinical signs of SN injury were also recorded at the same time points. The results were statistically analysed. RESULTS: There were no statistical significant differences on the occurrence of SN injury between groups A and B at two and 12 weeks, respectively, as confirmed with ENG studies and clinical evaluation. There were no differences between the two techniques with regard to the type of SN injury. SN injury was significantly ameliorated from 34% to 6% during the first three months. CONCLUSION: SN injury was equally observed after downwards or upwards total stripping of the GSV, as confirmed by ENG and clinical evaluation, with no differences in injury type. SN injury tends to be relieved through time in most patients.


Assuntos
Traumatismos dos Nervos Periféricos/etiologia , Veia Safena/inervação , Veia Safena/cirurgia , Varizes/cirurgia , Procedimentos Cirúrgicos Vasculares/efeitos adversos , Procedimentos Cirúrgicos Vasculares/métodos , Adulto , Eletrofisiologia , Feminino , Humanos , Incidência , Perna (Membro)/patologia , Masculino , Pessoa de Meia-Idade , Traumatismos dos Nervos Periféricos/fisiopatologia , Doenças do Sistema Nervoso Periférico/etiologia , Fatores de Tempo , Traumatismos do Sistema Nervoso/etiologia , Resultado do Tratamento , Varizes/complicações
7.
Biochim Biophys Acta ; 1834(6): 977-88, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23528423

RESUMO

Dynamics of uncrystallized water and protein was studied in hydrated pellets of the fibrous protein elastin in a wide hydration range (0 to 23wt.%), by differential scanning calorimetry (DSC), thermally stimulated depolarization current technique (TSDC) and dielectric relaxation spectroscopy (DRS). Additionally, water equilibrium sorption-desorption measurements (ESI) were performed at room temperature. The glass transition of the system was studied by DSC and its complex dependence on hydration water was verified. A critical water fraction of about 18wt.% was found, associated with a reorganization of water in the material. Three dielectric relaxations, associated to dynamics related to distinct uncrystallized water populations, were recorded by TSDC and DRS. The low temperature secondary relaxation of hydrophilic polar groups on the protein surface triggered by hydration water for almost dry samples contains contributions from water molecules themselves at higher water fractions (ν relaxation). This particular relaxation is attributed to water molecules in the primary and secondary hydration shells of the protein fibers. At higher temperatures and for water fraction values equal to or higher than 10wt.%, a local relaxation of water molecules condensed within small openings in the interior of the protein fibers was recorded. The evolution of this relaxation (w relaxation) with hydration level results in enhanced cooperativity at high water fraction values, implying the existence of "internal" water confined within the protein structure. At higher temperatures a relaxation associated with water dynamics within clusters between fibers (p relaxation) was also recorded, in the same hydration range.


Assuntos
Elastina/química , Água/química , Animais , Bovinos , Cristalização , Espectroscopia Dielétrica/métodos , Vidro/química , Interações Hidrofóbicas e Hidrofílicas , Temperatura
8.
QJM ; 106(5): 401-13, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23243293

RESUMO

BACKGROUND: It has been estimated that 1.3-6.4% of patients with inflammatory bowel diseases (IBD) are complicated by cerebral venous thrombosis (CVT) at some point of time during the course of their disease. METHODS: We retrospectively reviewed and subsequently analyzed data from 65 case reports of IBD patients with CVT. Our sources included MEDLINE and EMBASE, and the references of retrieved articles were also screened. RESULTS: Patients with CVT and IBD were significantly younger than CVT patients without IBD. Female patients were complicated more frequently but at an older age when compared with males. The incidence of ulcerative colitis was almost double compared with Crohn's disease. Active disease was detected in 78.4% of the cases and the proportions of patients with active ulcerative colitis or active Crohn's disease were almost equal. The predominant neurological symptom in these patients was persistent headache (80%) and the most common site of CVT was the superior sagittal sinus (50.7%). Severe iron deficiency anemia was highlighted as a significant risk factor for thrombosis in nearly half of the patients. Transient coagulation abnormalities and hereditary thrombogenic mutations were identified in 23 and 20% of the case reports, respectively. CONCLUSION: The overall outcome was very good, especially in those patients who were treated acutely with heparin or low molecular weight heparin, suggesting that heparin administration is related with improved neurological outcome and decreased mortality rates even in IBD patients complicated with CVT.


Assuntos
Doenças Inflamatórias Intestinais/complicações , Trombose dos Seios Intracranianos/etiologia , Anticoagulantes/uso terapêutico , Humanos , Prognóstico , Fatores de Risco , Trombose dos Seios Intracranianos/tratamento farmacológico , Resultado do Tratamento
9.
J Phys Chem B ; 116(15): 4593-602, 2012 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-22469064

RESUMO

Dielectric dynamic behavior of bovine serum albumin (BSA)-water mixtures over wide ranges of water fractions, from dry protein until 40 wt % in water, was studied through dielectric relaxation spectroscopy (DRS). The α relaxation associated with the glass transition of the hydrated system was identified. The evolution of the low temperature dielectric relaxation of small polar groups of the protein surface with hydration level results in the enhancement of dielectric response and the decrease of relaxation times, until a critical water fraction, which corresponds to the percolation threshold for protonic conductivity. For water fractions higher than the critical one, the position of the secondary ν relaxation of water saturates in the Arrhenius diagram, while contributions originating from water molecules in excess (uncrystallized water or ice) follow separate relaxation modes slower than the ν relaxation.


Assuntos
Soroalbumina Bovina/química , Água/química , Animais , Bovinos , Espectroscopia Dielétrica , Simulação de Dinâmica Molecular
10.
Biochim Biophys Acta ; 1814(12): 1984-96, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21798376

RESUMO

Protein-water dynamics in mixtures of water and a globular protein, bovine serum albumin (BSA), was studied over wide ranges of composition, in the form of solutions or hydrated solid pellets, by differential scanning calorimetry (DSC), thermally stimulated depolarization current technique (TSDC) and dielectric relaxation spectroscopy (DRS). Additionally, water equilibrium sorption isotherm (ESI) measurements were performed at room temperature. The crystallization and melting events were studied by DSC and the amount of uncrystallized water was calculated by the enthalpy of melting during heating. The glass transition of the system was detected by DSC for water contents higher than the critical water content corresponding to the formation of the first sorption layer of water molecules directly bound to primary hydration sites, namely 0.073 (grams of water per grams of dry protein), estimated by ESI. A strong plasticization of the T(g) was observed by DSC for hydration levels lower than those necessary for crystallization of water during cooling, i.e. lower than about 0.3 (grams of water per grams of hydrated protein) followed by a stabilization of T(g) at about -80°C for higher water contents. The α relaxation associated with the glass transition was also observed in dielectric measurements. In TSDC a microphase separation could be detected resulting in double T(g) for some hydration levels. A dielectric relaxation of small polar groups of the protein plasticized by water, overlapped by relaxations of uncrystallized water molecules, and a separate relaxation of water in the crystallized water phase (bulk ice crystals) were also recorded.


Assuntos
Soroalbumina Bovina/química , Soroalbumina Bovina/metabolismo , Água/química , Água/metabolismo , Animais , Varredura Diferencial de Calorimetria , Bovinos , Cristalização , Espectroscopia Dielétrica , Vidro/química , Cinética , Modelos Biológicos , Transição de Fase , Espectrometria de Massas por Ionização por Electrospray , Temperatura , Termodinâmica
11.
Eur Phys J E Soft Matter ; 34(4): 37, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21538222

RESUMO

Poly(ε-caprolactone)/poly(hydroxyethyl acrylate) networks have been investigated by thermally stimulated depolarization currents (TSDC) and differential scanning calorimetry (DSC). The introduction of hydrophilic units (HEA) in the system aiming at tailoring the hydrophilicity of the system results in a series of copolymer networks with microphase separation into hydrophobic/hydrophilic domains. Polycaprolactone (PCL) crystallization is prevented by the topological constraints HEA units imposed in such heterogeneous domains. Moreover, the mobility of the amorphous PCL chains is enhanced as revealed by the main relaxation process which becomes faster. The glass transition of PHEA-rich domains shifts to lower temperatures, as the total amount of PCL in the copolymer increases, due to the presence of PCL units within the same region. The behaviour of the copolymer networks swollen with different content of water has been investigated to analyze the interaction between water molecules and hydrophobic/hydrophilic domains and provide further insights into the molecular structure of the system.


Assuntos
Materiais Biocompatíveis/química , Poliésteres/química , Poli-Hidroxietil Metacrilato/química , Biofísica/métodos , Varredura Diferencial de Calorimetria/métodos , Cristalização , Vidro , Temperatura Alta , Cinética , Teste de Materiais , Estrutura Molecular , Polímeros/química , Temperatura , Água/química
12.
Br J Radiol ; 84(997): 78-80, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21172968

RESUMO

OBJECTIVE: Primary lateral sclerosis (PLS) is a progressive degenerative disorder affecting upper motor neurons and requires a clinical diagnosis. Diffusion tensor imaging (DTI) is a quantitative method for assessing white matter fibre integrity. The purpose of the study was to evaluate the involvement of upper motor neurons by using DTI in PLS. METHODS: A patient with PLS was compared with eight age-matched controls. Differences in fractional anisotropy (FA) index were assessed using DTI on a voxel-by-voxel basis. RESULTS: Decreased FA was observed in the proximal part of the pyramidal tract bilaterally, which indicated degeneration of the pyramidal cells. CONCLUSION: Voxel-based DTI could be used as an objective marker for detecting upper motor neuron degeneration in PLS.


Assuntos
Doença dos Neurônios Motores/patologia , Tratos Piramidais/patologia , Estudos de Casos e Controles , Imagem de Difusão por Ressonância Magnética , Progressão da Doença , Feminino , Humanos , Pessoa de Meia-Idade , Doença dos Neurônios Motores/fisiopatologia , Neurônios Motores/fisiologia , Condução Nervosa/fisiologia , Prognóstico , Tratos Piramidais/fisiopatologia
13.
Eur J Neurol ; 18(5): 719-25, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21087363

RESUMO

BACKGROUND AND PURPOSE: Several previous studies have employed optical coherence tomography (OCT) of the optic disc and 'white-on-white' automated perimetry to evaluate optic neuritis (ON) associated with multiple sclerosis (MS). This study employed OCT, white-on-white automated perimetry as well as 'blue-on-yellow' automated perimetry to evaluate MS patients with or without episodes of ON. METHODS: The MS group consisted of 56 patients with MS (27 patients with no history of ON in both eyes and 29 patients with at least one ON attack in one or both eyes), whereas the control group consisted of 56 age- and sex-matched healthy subjects. All patients underwent a complete neurological and ophthalmological examination. Peri-papillary retinal nerve fibre layer thickness (RNFLT) was evaluated using OCT. The mean defect and pattern standard deviation for both white-on-white and blue-on-yellow perimetry were also recorded. RESULTS: RNFLT and perimetric scores were significantly lower in MS group without a history of ON and in the unaffected eyes of MS group with unilateral ON, compared with controls. MS group with more than one ON episodes had significantly compromised blue-on-yellow perimetric indices, compared with patients with one ON episode, whereas respective differences for white-on-white perimetry were not statistically significant. CONCLUSIONS: The significantly lower RNFLT and perimetric scores in MS group patients without ON, compared with control group, may possibly be attributed to sub-clinical episodes of ON or to retrograde degeneration of nerve cells from sub-clinical post-chiasmal lesions. Blue-on-yellow perimetry may be advantageous over white-on-white perimetry in evaluating MS-associated functional defects.


Assuntos
Esclerose Múltipla/diagnóstico , Fibras Nervosas Mielinizadas/patologia , Nervo Óptico/patologia , Neurite Óptica/diagnóstico , Tomografia de Coerência Óptica/métodos , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Esclerose Múltipla/fisiopatologia , Nervo Óptico/fisiopatologia , Neurite Óptica/etiologia , Neurite Óptica/fisiopatologia , Adulto Jovem
14.
J Neuroimmunol ; 226(1-2): 136-42, 2010 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-20605226

RESUMO

AIM: To investigate the cellular and humoral immunity status of gliomas, and their association with the WHO grading system. MATERIAL AND METHODS: We have conducted a case-control study of 49 patients with gliomas and 30 healthy controls. We used ELISA assays, radial immunodiffusion, indirect immunofluorescence, latex test and flow cytometry assays to estimate preoperative in serum the immunological profile. RESULTS: Patients with glioma had significantly reduced amounts of IL2 (p=0.000), TNF-a (p=0.033), IgG (p=0.011), IgA (p=0.027),C4 (p=0.026) ,CD3+ (p=0.001), CD4+ (p=0.000), CD8+ (p=0.002), ratio CD4/CD8 (p=0.000), CD19+ (p=0.04) and elevated IL10 (p=0.05) compared with healthy controls. No statistically significant differences were observed concerning viral agents, total NK cells, IgM, IgE, IL16, granzyme-b, RF, ANA, ENA, anti-dsDNA and anti-cardiolipin antibodies. A higher WHO grade, after controlling for age and gender, was associated with decreased number of CD3+ (p=0.011), CD4+ (p=0.015), CD8+ (p=0.048) and ratio CD4/CD8 (p=0.027), as well as with decreased IL2 (p=0.018), C4 (p=0.02), and IgG (p=0.05). IL2 and CD4+ counts were significant predictors of grade. CONCLUSIONS: A shift from Th1 to Th2, a CD3+ and CD19+ lymphocytopenia, a diminished fraction CD4/CD8 and a reduced amount of immunoglobulins and complement were observed in the patients with gliomas. A higher WHO grade of the tumor was associated with greater impairments of immunity. Since defects of both humoral and cellular immunity were equally observed and significant predictors of grade were assessed, a preoperative evaluation of the immune system of patients with gliomas is being proposed.


Assuntos
Glioma/complicações , Glioma/imunologia , Doenças do Sistema Imunitário/etiologia , Neoplasias do Sistema Nervoso/complicações , Neoplasias do Sistema Nervoso/imunologia , Adulto , Idoso , Antígenos CD/sangue , Antígenos CD/imunologia , Estudos de Casos e Controles , Citocinas/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Citometria de Fluxo , Glioma/classificação , Glioma/diagnóstico , Humanos , Doenças do Sistema Imunitário/metabolismo , Modelos Logísticos , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Neoplasias do Sistema Nervoso/classificação , Neoplasias do Sistema Nervoso/diagnóstico , Estudos Retrospectivos , Estatísticas não Paramétricas , Organização Mundial da Saúde
15.
J Neurooncol ; 100(2): 157-64, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20336349

RESUMO

Phosphorylated (activated) forms of Janus Kinase 2 (pJAK-2) and STAT-5 transcription factor (pSTAT-5), which are preferentially expressed after binding of erythropoietin (Epo) to its receptor EpoR, are known to be implicated in the molecular mechanisms controlling brain development. The purpose of this study was to investigate the expression of these proteins (pJAK-2, pSTAT-5, and EpoR) in human brain tumors compared with normal brain. Using specific antibodies and immunohistochemistry on formalin-fixed, paraffin-embedded semi-serial tissue sections a total of 87 human brain tumors and samples from normal brain tissue were studied. pJAK-2/pSTAT-5 nuclear co-expression was detected in 39% of astrocytomas, 43% of oligodendrogliomas, 50% of ependymomas, and in all (100%) of the medulloblastomas examined. In contrast, most of the meningiomas showed weak or no immunoreactivity for pJAK-2/pSTAT-5 proteins. A significant percentage of tumors exhibited pSTAT-5 immunoreactivity, being pJAK-2 immunonegative. EpoR/pJAK-2/pSTAT-5 co-expression was detected in a small percentage of astrocytomas (18%) and ependymomas (33%). Oligodendrogliomas and medulloblastomas were EpoR immunonegative. Tumor vessels exhibited EpoR, pJAK-2, and pSTAT-5 immunoreactivity. In normal brain tissue, EpoR immunoreactivity was detected in neurons and vessels whereas pSTAT-5 and pJAK-2 immunoreactivity was limited to some neurons and a few glial cells, respectively. These results indicate the existence of ligand (other than Epo)-dependent or independent JAK-2 activation that leads to constitutive activation of STAT-5 in most human brain tumors. Given the oncogenic potential of the JAK/STAT pathway, detection of different pJAK-2 and pSTAT-5 expression profiles between groups of tumors may reflect differences in the biological behavior of the various human brain tumors.


Assuntos
Neoplasias Encefálicas/metabolismo , Janus Quinase 2/biossíntese , Receptores da Eritropoetina/biossíntese , Fator de Transcrição STAT5/biossíntese , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Criança , Pré-Escolar , Perfilação da Expressão Gênica , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Fosforilação , Transdução de Sinais/fisiologia , Adulto Jovem
16.
Eur J Neurol ; 17(5): 757-9, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-19930448

RESUMO

BACKGROUND: Paraoxonase (PON) is an HDL-associated enzyme that prevents low-density lipoprotein oxidation, playing a major role in the pathogenesis of atherosclerosis. PON genes polymorphisms may affect the corresponding enzyme activity. In this study, we examined the association of ischemic stroke with the three PON genes. METHODS: One hundred and seventy-eight patients hospitalized for ischemic stroke and 181 age- and sex-matched healthy controls were recruited. PON1(Q/R) 192, PON1(M/L) 55, and PON2(S/C) 311 polymorphisms were analyzed. RESULTS: The presence of the PON2 311C allele was significantly increased in patients with severe forms of ischemic stroke according to Modified Rankin Scale (P = 0.02, odds ratio = 2.215). No significant differences in genotype and allele distribution were observed between patients and controls. CONCLUSIONS: The PON2 311C allele was suggested as a possible predisposing factor for severe cases of ischemic stroke. Large-scale multicenter-controlled prospective studies are warranted to further explore the effects of PON polymorphisms on stroke susceptibility and severity.


Assuntos
Arildialquilfosfatase/genética , Polimorfismo Genético/genética , Índice de Gravidade de Doença , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/genética , Idoso , Aterosclerose/enzimologia , Aterosclerose/genética , Isquemia Encefálica/enzimologia , Isquemia Encefálica/genética , Estudos de Coortes , Feminino , Frequência do Gene/genética , Marcadores Genéticos/genética , Predisposição Genética para Doença/genética , Testes Genéticos , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade
17.
Cancer Gene Ther ; 16(10): 741-52, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19644531

RESUMO

Cancer gene therapy is based on the transfer of genetic material to cancer cells to modify a normal or abnormal cellular function, or to induce cell death. Modified viruses or stem cells have been used as carriers to transfer the genetic material to cancer cells avoiding trafficking through normal cells. However, although the current vectors have been successful in delivering genes in vitro and in vivo, little has been achieved with human cerebral gliomas. Poor transduction efficiency of viruses in human glioma cells and limited spread and distribution to the tumor limits our current expectations for successful gene therapy of central nervous system cancer until and if effective transfer vehicles are available. Nevertheless, continuing research in better vector development may overcome these limitations and offer a therapeutic advantage over the standard therapies for glioma.


Assuntos
Neoplasias Encefálicas/terapia , Terapia Genética/métodos , Glioma/terapia , Terapia Viral Oncolítica/métodos , Vírus Oncolíticos/fisiologia , Células-Tronco/fisiologia , Adenoviridae/genética , Adenoviridae/fisiologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/virologia , Glioma/genética , Glioma/virologia , Humanos , Vírus Oncolíticos/genética
18.
Neuroepidemiology ; 33(2): 89-95, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19494549

RESUMO

BACKGROUND: To investigate the epidemiologic and clinical characteristics (age, sex, tumor location, socioeconomic status) and potential predisposing factors (alcohol, tobacco, mobile phone use, severe head trauma) of cerebral gliomas in a defined area of Northwest Greece. METHODS: The prospective study was conducted in patients with gliomas referred to all 7 hospitals of a study area with a population of 488,435 inhabitants, from June 1, 2005, to May 31, 2007. Incidence rates (IR) were calculated as new cases diagnosed among residents of the study area during the study period per 100,000 inhabitants. A case-control study was carried out in order to study the possible association of the risk of glioma with smoking, alcohol, use of mobile phone, and severe cranial trauma. RESULTS: A total of 56 glioma incident cases were identified with IRs of glioma and glioblastoma (GBM) at 5.73/10(5)/year and 3.69/10(5)/year, respectively. A male to female ratio of 1.25 was obtained in the GBM group. IRs of glioma and GBM for both males and females were higher in the age group 60-79. The most frequent anatomic location was the frontal lobe. 46.5% of the patients originated from the low, 25% from the middle and 28.5% from the high socioeconomic class. There was no significant association between glioma and alcohol consumption, smoking and mobile phone use. A trend for a positive association between the risk of glioma and a history of severe cranial trauma was observed, but this association was not statistically significant. CONCLUSION: The estimated IR of glioma and GBM in this study was higher compared with data from other studies carried out on European, Asian and US populations. Further studies may be needed to assess the possible association of genetic, environmental and lifestyle factors with the high occurrence of gliomas observed in this study.


Assuntos
Neoplasias Encefálicas/epidemiologia , Glioma/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Consumo de Bebidas Alcoólicas/epidemiologia , Encéfalo/patologia , Neoplasias Encefálicas/patologia , Causalidade , Telefone Celular , Traumatismos Craniocerebrais/epidemiologia , Feminino , Glioma/patologia , Grécia/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , População Rural , Fatores Sexuais , Fumar/epidemiologia , Classe Social , População Urbana , Adulto Jovem
19.
Neuroepidemiology ; 33(2): 96-102, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19494550

RESUMO

BACKGROUND: We assessed the incidence and determinants of aphasia attributable to first-ever acute stroke. We also investigated early and long-term mortality and 1-year dependence in post-stroke patients. METHODS: A 10-year prospective hospital-based study was conducted in the prefecture of Athens, Greece. RESULTS: In total, 2,297 patients were included in the study, of whom 806 (35.1%) had aphasia. The presence of aphasia was independently associated with increasing age (OR: 1.19 per 10-year increase, 95% CI: 1.12-1.21) and atrial fibrillation (OR: 1.35, 95% CI: 1.08-1.67), and inversely associated with Scandinavian Stroke Scale (SSS) score (OR: 0.55 per 10-point increase, 95% CI: 0.52-0.59) and hypertension (OR: 0.77, 95% CI: 0.63-0.96). One-year dependence score (calculated with the modified Rankin score) was higher in aphasic patients compared to non-aphasics (p < 0.001). Moreover, severity of aphasia (estimated with a subscale of SSS) was found as an independent predictor of 1-year dependence. Most of the deaths in the aphasic patients were attributed to infections and neurological damage. Using the Kaplan-Meier limit method, the unadjusted probability of 10-year mortality was demonstrated to increase with the severity of aphasia (log-rank test: 233.9, p < 0.001) and, even after adjustment for several other factors, severity of aphasia remained an independent predictor of 10-year mortality. CONCLUSIONS: Increasing age, atrial fibrillation and severity of stroke were associated with the risk of aphasia after stroke. Severity of aphasia is a strong predictor of long-term mortality and dependence of post-stroke patients.


Assuntos
Afasia/etiologia , Acidente Vascular Cerebral/complicações , Idoso , Afasia/mortalidade , Afasia/terapia , Causas de Morte , Estudos de Coortes , Feminino , Escala de Coma de Glasgow , Grécia/epidemiologia , Hospitalização , Humanos , Hipertensão/complicações , Hipertensão/epidemiologia , Estimativa de Kaplan-Meier , Masculino , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Acidente Vascular Cerebral/mortalidade , Acidente Vascular Cerebral/terapia , Resultado do Tratamento
20.
Neurology ; 72(21): 1816-22, 2009 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-19470963

RESUMO

OBJECTIVE: To determine whether statin therapy after hospital discharge affects ischemic stroke recurrence and long-term mortality in patients admitted for a first-ever occurrence of ischemic stroke. METHODS: This was a retrospective observational study involving linked hospitalization and death records. The cohort comprised a series of 794 consecutive, first-ever acute ischemic stroke patients from the Athenian Stroke Registry, admitted to the acute stroke unit and the general medicine and neurology ward of our institutions since January 1997 for whom there was available information covering a 10-year follow-up period. Cox proportional hazards model was used to identify risk factors for stroke recurrence and death. RESULTS: The recurrence rate was 16.3% among stroke patients not receiving a statin after hospital discharge compared with 7.5% among those who received statin therapy (p = 0.002). Cox regression analyses revealed only statin therapy postdischarge to be a significant independent predictor of stroke recurrence (adjusted hazard ratio [HR], 0.65, 95% confidence interval [CI] 0.39 to 0.97, p < 0.01). Similarly, patients receiving a statin had a significantly lower mortality during the 10-year period after the acute cerebrovascular event (adjusted HR, 0.43; 95% CI 0.29 to 0.61, p < 0.01). CONCLUSIONS: Prescribing statin therapy upon hospital discharge to patients with first-ever acute stroke lowers the risk of 10-year stroke recurrence and improves survival.


Assuntos
Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/prevenção & controle , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/prevenção & controle , Idoso , Isquemia Encefálica/mortalidade , Estudos de Coortes , Intervalos de Confiança , Feminino , Seguimentos , Previsões , Humanos , Estimativa de Kaplan-Meier , Masculino , Análise Multivariada , Modelos de Riscos Proporcionais , Sistema de Registros , Análise de Regressão , Estudos Retrospectivos , Prevenção Secundária , Acidente Vascular Cerebral/mortalidade , Resultado do Tratamento
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