RESUMO
We characterized a symptomatic CRMred factor X (FX) deficiency produced by the Glu19Ala mutation in the gamma-carboxyglutamic-rich domain. FX activity levels in plasma were markedly reduced in prothrombin time assays (< 1-5%), whereas in activated partial thromboplastin assays (16%) and in RVV assays (17%) the reduction in activity mirrored that in antigen levels (17%). Activation of recombinant 19Ala-FX by factor IXa/factor VIIIa or RVV, and the activity in thrombin generation assays, were comparable to those of wild-type FX. Differently, complete activation of recombinant 19Ala-FX required a factor VIIa/TF concentration 30-fold higher than that of wild-type FX. The recombinant FVIIa significantly reduced PT values in 19Ala-FX reconstituted plasma, thus suggesting an alternative approach for treatment of FX deficiencies characterized by defective FX activation. The study of this FX deficiency provides an "in vivo" and "in vitro" model for the investigation of Gla domain interactions.
Assuntos
Coagulação Sanguínea/genética , Deficiência do Fator X/genética , Fator X/genética , Fator X/metabolismo , Mutação de Sentido Incorreto , Testes de Coagulação Sanguínea , Linhagem Celular , Saúde da Família , Feminino , Variação Genética , Humanos , Pessoa de Meia-Idade , Linhagem , TransfecçãoRESUMO
A scanning soft x-ray microscope has been developed that uses synchrotron radiation focused by a Fresnel zone plate to form a submicron beamspot on the specimen. Transmitted x-rays are detected and used to form a quantitative map of specimen absorptivity. Applications of the instrument to the imaging of whole wet cells and to the mapping of calcium in sections of bone are presented, with a resolution of 300 nm and an elemental sensitivity of 2 micrograms cm-2.
Assuntos
Neurônios/diagnóstico por imagem , Crânio/diagnóstico por imagem , Animais , Axônios/diagnóstico por imagem , Axônios/ultraestrutura , Células Cultivadas , Microanálise por Sonda Eletrônica/métodos , Humanos , Neurônios/citologia , Radiografia , Raios XRESUMO
X-ray differential absorption microanalysis is presented as a technique for trace element analysis of hydrated biological specimens of about 0.1-5 µm thickness. For the study of the light elements (Zâ²20), the absorption technique minimizes the radiation dose and, thus, damage to such specimens when compared with X-ray fluorescence. A Scanning Transmission X-ray Microscope (SXTM) is described, which has been used to map the concentration of calcium in bone with better than 300 nm spatial resolution and a sensitivity to 5% calcium by weight. Future plans are briefly discussed that offer the hope of achieving 0.1% trace element sensitivity and 75 nm spatial resolution.
RESUMO
BACKGROUND: The measurement of the dispersion of the QT interval reflects regional repolarization differences in the heart which in turn can elicit the onset of arrhythmias by means of re-entry mechanism. Therefore, inter-lead QT dispersion has been proposed as novel indicator of arrhythmogenic risk that can predict severe ventricular arrhythmias or sudden death. The present study was conducted to evaluate QT dispersion in diabetic insulin-dependent patients with autonomic neuropathy. METHODS: We recruited three groups of 10 patients with the same age, sex, body weight distribution: 1) group DAN+ (diabetics with neuropathy); 2) group DAN- (diabetics without neuropathy); and 3) group CTRL (healthy control group). The patients underwent two-dimensional color-Doppler echocardiography and 12-lead electrocardiogram, 25 and 50 mm/s paper speed (gain 10 mm/mU). The QTc dispersion was determined as the difference between the maximum and the minimum value of the QTc interval in different leads of the ECG recording. QT interval was corrected (QTc) by heart rate according to the Bazett's formula. Cardiovascular autonomic function was evaluated by Ewing's tests (heart rate and blood pressure measurement during lying to standing, deep breathing, hand-grip isometric stress test and Valsalva's maneuver). RESULTS: QT dispersion was significantly greater (p < 0.01) in the patients with autonomic neuropathy (51 +/- 10 ms) than in the patients without autonomic neuropathy (29 +/- 6 ms) or in healthy control subjects (26 +/- 5 ms). CONCLUSIONS: Our data suggest that diabetic neuropathy, associated with an increased QT dispersion, shows a higher risk for serious ventricular arrhythmias and sudden cardiac death.
Assuntos
Diabetes Mellitus Tipo 1/fisiopatologia , Eletrocardiografia , Adulto , Doenças do Sistema Nervoso Autônomo/diagnóstico , Doenças do Sistema Nervoso Autônomo/fisiopatologia , Diabetes Mellitus Tipo 1/diagnóstico , Neuropatias Diabéticas/diagnóstico , Neuropatias Diabéticas/fisiopatologia , Ecocardiografia Doppler em Cores , Eletrocardiografia/métodos , Eletrocardiografia/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
This article describes the scanning transmission X-ray microscope operated at the National Synchroton Light Source. The application of the instrument to elemental analysis is detailed. In particular, qualitative results on the calcium distribution in human skull tissue are presented.