RESUMEN
This paper presents a new on-chip electrospray ionisation (ESI) nozzle, which can be used as an interface for coupling microfluidic devices with mass spectrometric (MS) detection. The nozzle was micromilled in a polymer foil (polymethylmethacrylate (PMMA) 750 microm thick), normally used as a cover for microfluidic chips. The performance of this device was examined in the ESI-MS analysis of the tetrapeptide MRFA (methionine-argenine-phenylalanine-alanine). The spray quality is basically dependent on the inner diameter of the nozzle, beside the part of the organic modifier in the solution to be sprayed. Three different inner nozzle diameters (30, 50, 100 microm) and two different apex angles were investigated. Stable electrospray conditions can be generated with a relative standard deviation less than 10% of the total ion current, and down to a concentration of 0.01 micromol L(-1). The production of this ESI interface is relatively simple for the purpose of a low-cost batch fabrication of miniaturized analytical instruments.
RESUMEN
The coexistence of arterial hypertension and disturbances of haemostasis in pregnant women with EPH-gestosis allow to expect a role of fibrinolysis and kinin-forming systems in pathomechanism of this syndrome. For these reasons blood plasma of 34 patients with EPH-gestosis, 23 patients with normal pregnancy and 19 nonpregnant women was investigated. All pregnant women were in third trimester of pregnancy. The following parameters were investigated: kinin-forming system compounds (kininogens and prokininogenases - biological methods), fibrinolytic activity (plasma euglobulin fibrinolysis time), total plasma protein and fibrinogen concentration, protease inhibitors - antithrombin III, C1-esterase inhibitor, alpha 2-antiplasmin, alpha 1-protease inhibitor and alpha 2-macroglobulin (by electroimmunodiffusion). Furthermore hematocrit was measured. In pregnant women with EPH-gestosis significant increase of high molecular weight kininogen concentration was found (p less than 0.02), decreased fibrinolytic activity (p less than 0.01) and (except alpha 2-antiplasmin) decreased concentration of protease inhibitors (p less than 0.005 - p less than 0.01) were observed. Further statistical analysis demonstrated positive correlation between the concentrations of kininogens and prokallikrein-prokininogenases and between low molecular weight kininogen and plasma euglobulin fibrinolysis time. On the other hand negative correlation between concentrations of those proenzymes and severity of gestosis was observed. The above described phenomena indicate on significance of disturbances of proteolytic enzyme activation in pathogenesis of EPH-gestosis.
