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We aimed at exploring the feasibility of noninvasive late arterial phase enhanced CT imaging in evaluating tumor angiogenesis, ischemic necrosis, and glucose metabolism, thereby providing pathological information for the comprehensive treatment plan in non-small cell lung cancer (NSCLC).52 cases of NSCLC were enrolled in this study. The mean ischemia necrosis CT quantitative value (INCTQ) and CT enhanced value (CTe) of the tumor were determined, and the immunohistochemical staining of factors relating to tumor angiogenesis, ischemic necrosis and glucose metabolism, including VEGF, VEGFR-2, HIF-1α, CAIX, GLUT1, and GLUT3, were conducted.The mean INCTQ values of different expression grades of VEGF, VEGFR-2, HIF-1α, and CAIX have no significant difference, but the mean INCTQ values of different expression grades of GLUT1 or GLUT3 have significant differences (p0.001), respectively. However, INCTQ value has a positive correlation with CAIX expression. In addition, CTe value was positively correlated with VEGF.To sum up, late arterial phase CT enhanced images of NSCLC not only can assess the tumor angiogenesis, but also can reflect the degree of ischemic necrosis, effectively reflecting the level of glucose metabolism in tumor and tumor angiogenesis, for the comprehensive treatment program.

Calorimetric measurement of adsorption enthalpies of native lysozyme(Lyz) on a moderately hydrophobic surface at 25°C, pH 7.0 and various salt concentrations was performed. Based on the thermodynamics of stoichiometric displacement theory (SDT), we calculated the fractions of thermodynamic functions involving four subprocesses during a displacement adsorption process from the directly determined enthalpies in combination with adsorption isotherm measurements. The thermodynamic fractions reveal the relative degree of the four subprocesses for contributions to enthalpy, entropy and free energy. The results show that native Lyz adsorption on a moderately hydrophobic surface is an entropy driven process contributed mainly by conformational loss of adsorbed Lyz.

Both microcalorimetric determination of displacement adsorption enthalpies ΔH and measurement of adsorbed amounts of guanidine – denatured lysozyme (Lys) refolding on the surface of hydrophobic interaction chromatography (HIC) packings at 308 K were carried out and compared with that at 298 K. Study shows that both temperature and concentration of guanidine hydrochloride (GuHCl) affect the molecular mechanism of hydrophobic interaction of protein with adsorbent based on the analysis of dividing ΔH values into three kinds of enthalpy fractions. The adsorption in higher concentrations of GuHCl (>1.3 mol L–1) at 308 K is an enthalpy-driving process, and the adsorption under other GuHCl concentrations is an entropy-driving process. The fact that the Lys denatured by 1.8 mol L–1 GuHCl forms a relatively stable intermediate state under the studied conditions will not be changed by temperature.

The displacement adsorption enthalpies (ΔH) of the refolding of lysozyme (Lys) denatured by 1.8 mol L–1 guanidine hydrochloride (GuHCl) on a moderately hydrophobic surface at 298 K, pH 7.0 and various (NH4)2SO4 concentrations were determined by using a Micro DSC-III calorimeter. The study shows that the effect of salt concentrations on the three fractions of the enthalpy is that with increasing (NH4)2SO4 concentrations, the molecular conformation enthalpy of the adsorbed Lys has probably no distinct change at 1.8 mol L–1 GuHCl; the adsorption affinity enthalpy (exothermic) becomes more negative; and the dehydration enthalpy (endothermic) decreases. At lower salt concentrations, the dehydration, especially squeezing water molecules led by molecular conformation, which leads to an entropy-driving process, predominates over the adsorption affinity (also including the orderly orientation of molecular conformation), while at higher salt concentrations, the latter is prior to the former for contribution to ΔH and induces an enthalpy-driving process. Also, the optimal NH4)2SO4 concentration favoring refolding and renaturing of Lys denatured by 1.8 mol L–1 GuHCl was found.

Calorimetric determination of the total enthalpy changes (ΔH i ) of guanidine-denatured lysozyme (Lys) during the adsorption with simultaneously refolding on the surface of hydrophobic interaction chromatography packings was carried out at 25±0.001°C. The measured ΔH i in the circumstances should include the changes in the three fractions: adsorption, dehydration and molecular conformation. It was found that when the unfolded Lys molecules are adsorbed and refold on the surface, entropy-driving caused by the dehydration of Lys mainly dominates the foregoing process. The refolding enthalpies of Lys, ΔΔH i were found to be 10∼100 folds higher than that measured in usual solutions.

Based on the stoichiometric displacement model for retention (SDM-R) in high performance liquid chromatography(HPLC), the biopolymer retentions are mainly dominated by displacer's concentration in mobile phase. According to this conclusion, an equation is presented for evaluating the minimum amount of mobile phase used for the preparative purpose with the unit of simultaneous renaturation and purification of proteins (USRPP) by linear gradient elution. Furthermore, the resolution and refolding efficiency of lysozyme were found to be independent of the flow-rate and gradient time when the amount of mobile phase was kept constant. The conclusions were tested by experiments and a good coincidence was obtained.

The retention behavior of aromatic alcohol homologues in hydrophobic interaction chromatography (HIC) was investigated for the first time. The differences in retention behavior between proteins and small solutes, and the eluted range and ability of different salts to small solutes and biopolymers, are elucidated with the parameter Z of the stoichiometric displacement retention model. The retention of aromatic alcohols follows the homologue rule. By the comparison of the changes of Z in different salt solutions, it is found that for small molecules the salt type only changes the hydration degree; but for proteins, it not only changes the hydration of proteins and stationary phase, but also affects the conformation of protein molecules near the contact regions between the protein and the stationary phase surface.

The reversed-phase chromatographic method consisting of acetic acid-water as a new mobile phase for separating biopolymers on ODS column is presented. The new mobile phase may overcome the weak points of irreversible adsorption in chromatographic separation to some degree and difficulty in concentrating proteins with lyophylization and reduce the three-component (organic solvent, ion-pairing agent and water) of typical mobile phase to two component system. Based on the retention and Z (the number of solvent molecules involving in the displacement from stationary-phase surface), log I (a constant relating to the affinity of 1 mol of solute to the bonded stationary phase), and j (a constant relating to the affinity of 1 mol of solvent to the bonded stationary phase), the elution strength of acetic acid-water mobile phase was found to be stronger than that of methanol-water-TFA. From a good linear relationship between log I and Z, it can be concluded that the interaction force between proteins and RPLC stationary phase with acetic acid-water as mobile phase is non-selective hydrophobic interaction forces. In addition, the molecular conformations of protein in acetic acid-water and methanol-trifluoroacetic acid-water were found to be different.

The recent development of the molecular conformation, renaturation and intermediates on therapeutic proteins produced in biotechnology is reviewed. It also includs the quality control and in preparation of the therapeutic proteins in large scale by liquid chromatography in down-stream technology. This review includes 42 references.

Based on the physical meanings of Z (total moles of the released solvent at the contact region between solute and stationary phase), and j(the slope of the linear plot of lg I versus Z, a constant relating to the affinity of organic solvent to the stationary phase) of stoichiometric displacement model for retention (SDM-R) of solute in liquid chromatography(LC), both Z and j could be employed to characterize solvents, therefore, Z value only can be used as a characterization parameter for fixed solute and stationary phase. However, the parameter j is independent of solutes. As long as phase is given, j can be employed as a new characterization parameter of organic solvent strength in LC. With the homologues of methanol, ethanol and n-propanol as organic solvents in mobile phase and n-alkylalcohols as solutes, both the SDM-R and Snyder's empirical equation were tested, and compared with the corresponding parameters obtained from Snyder's empirical equation. With S [the slope of the linear plot of lg k' (k' is capacity factor) vs psi(volume fraction of organic solvent in mobile phase)] and lg kw0(the intercept of this plot), it was found that the two linear plots with the SDM-R, lg k' vs the composition of mobile phase and lg I vs Z were better than the corresponding plots with Snyder's empirical equation. The results indicate that Z, lg I and j decrease with the increase in the molecular size of the organic solvent of the homologue. This fact indicates that the solvent strength in LC depends on the size of solvent molecules. And the greater the solvent molecules, the stronger the solvent strength is. Furthermore the solvent strength was found to follow homologous rule. The j value may become a new parameter for the characterization of organic solvent strength in LC.

A quantitative relationship between lg I (a constant relating to the affinity of one mole of solute to stationary phase) and Z (total moles of organic solvent released at the contact region as one mole solute adsorbed by stationary phase) in the stoichiometric displacement model for retention (SDM-R) of solute was compared with the corresponding relationship in Snyder's Equation in reversed-phase liquid chromatography (RPLC). It was found that the relationship from SDM-R was more exact than that from Snyder's Equation. The linearity depends on the ranges of both lg I and lg Kw0. The broader the range, the better the linearity is. This conclusion conflicts to that reported in references in which the linearity only exists either when one factor dominates solute retention, or when it is completely dominated by statistics. The linear relationship in SDM-R and in Snyder's Equation was found valid not only for homologues but also for non-homologues.

Based on the physical meaning of each term in the linear parameter log I (a constant correlating the affinity of solute to stationary phase) of stoichiometric displacement model for retention(SDM-R) of solute, the thermodynamic characteristics of log I of solute in reversed-phase liquid chromatography (RPLC) were investigated theoretically. This point was tested by experimental data with two linear relationships: (1) plot of log I vs 1/T (T is absolute temperature) with apolar, polar small solutes and proteins; (2) plot of log I vs log Po/w (partition coefficient of solute between n-octanol and water) with apolar and polar small solutes. From the comparison of the magnitude of partition coefficient between small solute and proteins, a phenomenon that the resolution of small solutes depends on column length but that of proteins almost to be independent of column length is quantitatively explained.