Sera and urine from patients with severe uremia and healthy subjects were seperated by means of gel permeation chromatography on Sephadex G15 column with N(C 2H 5) 3 H 2CO 3 buffer as eluent. Two middle molecular peaks(A and B) were detected at 206 nm in normal urine, uremic serum and uremic urine, but these two peaks were hardly observed in the profile of normal sera. In contrast, the absorption at 206 nm of fractions A and B from uremic serum and urine were less than that of fractions A and B from normal urine. Fractions A from normal urine, uremic serum and urine were collected and resolved into 8 to 9 subpeaks at 230 nm by anion exchange chromatography. One of these subpeaks, A 3, was detected in uremic serum and normal urine but undetectable in uremic urine. After a gel permeation chromatography with bidistilled water as eluent for desalting, subfraction A 3 was seperated into two parts designated A 3 Ⅰ and A 3 Ⅱ in order. The results of MALDI TOF MS revealed that the two peaks from both samples were identical respectively, fraction A 3 Ⅰ contained three kinds of components with molecular weight 839.69, 1 007.94 and 2 015.16 and fraction A 3 Ⅱ consisted of other three kinds of components with molecular weight 873.69, 1 106.67 and 1 680.28.
A uremic toxic compound with molecular weight 1007.94 was determined to be an octapeptide by mass spectrometry.Its amino-acid sequence was given as follos: Val-Val-Arg-Gly-Cys-Thr-Trp-Trp.Spin systems for amino acid residues in the octapeptide were identified through analysis of 2D NMR 1H-1H DQF-COSY,TOCSY and ROESY spectra acquired in H2O and D2O.Moreover,the complete assignment of proton resonances for the backbone and side chain was achieved.Based on the secondary chemical shift（Δδ） of the residues,the secondary structure of octapeptide was surveyed.Conformational analyses according to Chemical Shift Index（CSI） showed that the secondary structure of the octapeptide was principally α-helix.The CD spectra of the peptide in aqueous solution gave the same result.Additions of linear polymers made the conformations of octapeptide stretch.These experimental results provide a basis for further comprehension of interaction regulation between biomacromolecule and polymer absorbing materials.
Endotoxin is lipopolysaccharide(LPS) derived from the cell membrane of gram-negative bacteria. The concentration of endotoxin in endotoxemia patients′ blood increases quickly and leads to severe sepsis, leading to severe hypertension, cardiovascular continues to have a high failure and death, which is a major cause of death in patients and continues to have a high mortality despite appropriate surgery, potent antibiotic and intensive supportive therapy was conducted. Removal of endotoxin duly and effectually from patients′ blood is very important in clinic. Hemoperfusion can clear toxins from patient′s blood by adsorbent, not only small molecular toxins but also large ones in time. In this paper, the hemoperfusion adsorbent for removing endotoxin was prepared. The physical and chemical parameter of the adsorbent is investigated and the surface structure of adsorbent was investigated through ESEM. The influence of weights of adsorbents and adsorbing time on adsorption ability was also studied. The results showed that the adsorbent with lysine as the ligand had good affinity to endotoxin and the best adsorption capacity of it was 253.1 EU/g when the initial concentration is 10 EU/mL. The blood compatibility of the adsorbent was also studied and the results indicated that the adsorbent has clinic application foreground.
Sera and urine from patients with severe uremia and healthy persons were separated by means of gel permeation chromatography on Sephadex G-15 column with N（C2H5）3-H2CO3 buffer as the eluent. Two middle molecular peaks（A and B） were detected at 206 nm in normal urine, uremic serum and uremic urine, but these two peaks were hardly observed in the profile of normal sera. In contrast, the absorption at 206 nm of fractions A and B from uremic urine were smaller than that of fractions A and B from normal urine. Fractions A from normal urine, uremic serum and urine were collected and resolved into 3 subpeaks at 254 nm by high performance liquid chromatography. Two of these subpeaks, A-Ⅰ and A-Ⅱ, were detected in uremic serum, normal urine and uremic urine. The results of MALDI-TOF-MS revealed that the fraction A-Ⅰ from both uremic serum and normal urine contained a component with molecular weight {1 214}, which could hardly be seen in the fraction A-Ⅰ of uremic urine.
