Gel permeation chromatography: The effect of flow rate on efficiency. II

1983 ◽  
Vol 28 (2) ◽  
pp. 473-483 ◽  
Author(s):  
Jau-Yi Chuang ◽  
Julian F. Johnson ◽  
Anthony R. Cooper
Keyword(s):  
Flow Rate ◽  
Gel Permeation Chromatography ◽  
Gel Permeation

scholarly journals Effects of the electrosprayed polycaprolactone microparticles morphology on the polycaprolactone degradation

2019 ◽  
Vol 3 (2) ◽  
pp. 65-73
Author(s):  
Nguyen-Vu Viet Linh ◽  
Nguyen Quoc Viet ◽  
Huynh Dai Phu
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Protein Delivery ◽  
Gel Permeation Chromatography ◽  
Processing Parameters ◽  
The Body ◽  
Processing Parameter ◽  
Gel Permeation ◽  
Polymeric Microparticles ◽  
Scanning Electron

The polycaprolactone (PCL) microparticles fabricated by electrospray technique have been studied and applied in drug and protein delivery system. The degradation of PCL and the release of drug/protein from the polymeric microparticles (MPs) were desired to happen simultaneously. When the new dosage was administrated, the PCL MPs were degraded and eliminated out of the body. This research indicated that the degradation of PCL was influenced by the various morphology of electrosprayed microparticles. The different sizes of 11.8 μm and 5.17 μm and the various shapes of the PCL MPs such as hollow, porous and wrinkle particles and spheres were investigated the PCL degradation in the PBS solution, at pH 7.4. The morphology of PCL MPs was designed by controlling the polymer solution and the electrosprayed processing parameters such as the flow rate and collecting distance. Scanning electron microscopy and gel permeation chromatography were order to determine the change of the morphology and number molecule weight (Mn) of PCL MPs. The porous, distorted and smaller particles reduced the Mn faster than the microspheres because of the larger surface area of MPs contacted with PBS solution. After 77 days, PCL MPs which were fabricated by the processing parameter, including 2.5% PCL in DCM, flow rate of 0.8 mL/h, voltage of 18 kV, collecting distance of 25 cm, reduced 49.96% molecular weight (decreasing from Mn= 80,438 g/mol to 40,225 g/mol).  

Aggregated, Conformationally Changed Fibrinogen Exposes the Stimulating Sites for t-PA-Catalysed Plasminogen Activation

1996 ◽  
Vol 75 (02) ◽  
pp. 326-331 ◽  
Author(s):  
Unni Haddeland ◽  
Knut Sletten ◽  
Anne Bennick ◽  
Willem Nieuwenhuizen ◽  
Frank Brosstad
Keyword(s):  
Conformational Changes ◽  
Gel Permeation Chromatography ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Chromogenic Substrate ◽  
Type Plasminogen Activator ◽  
Gel Permeation ◽  
Self Association ◽  
Fibrin Monomers ◽  
Stimulation Of

SummaryThe present paper shows that conformationally changed fibrinogen can expose the sites Aα-(148-160) and γ-(312-324) involved in stimulation of the tissue-type plasminogen activator (t-PA)-catalysed plasminogen activation. The exposure of the stimulating sites was determined by ELISA using mABs directed to these sites, and was shown to coincide with stimulation of t-PA-catalysed plasminogen activation as assessed in an assay using a chromogenic substrate for plasmin. Gel permeation chromatography of fibrinogen conformationally changed by heat (46.5° C for 25 min) demonstrated the presence of both aggregated and monomeric fibrinogen. The aggregated fibrinogen, but not the monomeric fibrinogen, had exposed the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation. Fibrinogen subjected to heat in the presence of 3 mM of the tetrapeptide GPRP neither aggregates nor exposes the rate-enhancing sites. Thus, aggregation and exposure of t-PA-stimulating sites in fibrinogen seem to be related phenomena, and it is tempting to believe that the exposure of stimulating sites is a consequence of the conformational changes that occur during aggregation, or self-association. Fibrin monomers kept in a monomeric state by a final GPRP concentration of 3 mM do not expose the epitopes Aα-(148-160) and γ-(312-324) involved in t-PA-stimulation, whereas dilution of GPRP to a concentration that is no longer anti-polymerizing, results in exposure of these sites. Consequently, the exposure of t-PA-stimulating sites in fibrin as well is due to the conformational changes that occur during selfassociation.

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