ABSTRACT
This work describes the use of a reverse phase (RP) column for size-based separation of hydrophilic polysaccharides. The entire separation window (before and after void volume) is used to provide unique separation of polysaccharides from other components in a glycol-conjugate vaccine or complex media of fermentation broth. The technique has also been applied to the separation of polysaccharides of different sizes. The effect of chromatographic parameters including type of packing material (CN, C8 and C18), pore size (80 and 300Å) of stationary phase, concentration of organic solvent on the separation was investigated. In addition, characterization of size-based separation was evaluated by coupling of RP column with multi-angle laser light scattering (MALLs) detector.
Subject(s)
Chromatography, Gel , Chromatography, Reverse-Phase , Polysaccharides/isolation & purification , Chromatography, Reverse-Phase/instrumentation , Complex Mixtures/chemistry , DNA/chemistry , DNA/isolation & purification , Hydrophobic and Hydrophilic Interactions , Molecular Weight , Particle Size , Polysaccharides/chemistry , Proteins/chemistry , Proteins/isolation & purificationABSTRACT
We extend our recently published windkessel-wave interpretation of vascular function to the wave intensity analysis (WIA) of left ventricular (LV) filling dynamics by separating the pressure changes due to the windkessel from those due to traveling waves. With the use of LV compliance, the change in pressure due solely to LV volume changes (windkessel pressure) can be isolated. Inasmuch as the pressure measured in the cardiovascular system is the sum of its windkessel and wave components (excess pressure), it can be substituted into WIA, yielding the isolated wave effects on LV filling. Our study of six open-chest dogs demonstrated that once the windkessel effects are removed from WIA, the energy of diastolic suction is 2.6 times greater than we previously calculated. Volume-related changes in pressure (i.e., the windkessel or reservoir effect) must be considered first when wave motion is analyzed.
Subject(s)
Aorta/physiology , Coronary Circulation/physiology , Models, Cardiovascular , Ventricular Function, Left/physiology , Animals , Blood Flow Velocity , Blood Pressure , Compliance , Dogs , Heart Rate/physiology , Linear Models , Mitral Valve/physiology , Research Design , Stroke Volume , Time Factors , Ventricular PressureABSTRACT
The left atrium (LA) acts as a booster pump during late diastole, generating the Doppler transmitral A wave and contributing incrementally to left ventricular (LV) filling. However, after volume loading and in certain disease states, LA contraction fills the LV less effectively, and retrograde flow (i.e., the Doppler Ar wave) into the pulmonary veins increases. The purpose of this study was to provide an energetic analysis of LA contraction to clarify the mechanisms responsible for changes in forward and backward flow. Wave intensity analysis was performed at the mitral valve and a pulmonary vein orifice. As operative LV stiffness increased with progressive volume loading, the reflection coefficient (i.e., energy of reflected wave/energy of incident wave) also increased. This reflected wave decelerated the forward movement of blood through the mitral valve and was transmitted through the LA, accelerating retrograde blood flow in the pulmonary veins. Although total LA work increased with volume loading, the forward hydraulic work decreased and backward hydraulic work increased. Thus wave reflection due to increased LV stiffness accounts for the decrease in the A wave and the increase in the Ar wave measured by Doppler.
