Objective To investigate the effects of different stabilizers, time and temperature before centrifugation on the stability of homocysteine (Hcy) and other related thiols levels involving EDTA-containing whole blood.Methods Blood was drawn from 17 healthy adults and collected into tubes containing EDTA, EDTA plus NaF and EDTA plus 3-deazaadenosine(3DA),then stored on crush ice(0-4 ℃) immediately or at room temperature(25 ℃).Plasma was separated at 0, 3, 6, 24 and 48 hours, respectively.The levels of plasma total Hcy (tHcy), total cysteine (tCys), tatal cysteinylglycine (tCysGly) and tatal glutathione (tGSH) were measured by HPLC.The plasma immediately separated was used as baseline sample. Results In EDTA tubes stored at room temperature, tHcy levels increased by 38.5%, 64.2%, 141.9%, 225.4% for 3, 6, 24, and 48 h, respectively.The levels of tCysGly and tGSH increased by 20.0% and 37.9% within 3 h, however, tCys decreased by 3.5%.The levels of the thiols increase by less than 5% up to 6 h in EDTA tubes stored on crush ice.In EDTA-3DA and EDTA-NaF tubes, no statistical differences were observed in the plasma levels of tHcy, tCys,tCysGly and tGSH compared with their respective baseline values at room temperature for 3 h(EDTA-3DA tubes:F=0.01,0.94,0.09,0.01,all P>0.05;EDTA-NaF tubes:F=0.85,0.04,0.03,0.02,all P>0.05).Conclusions The EDTA-plasma levels of tHcy and other related thiols are time and temperature-dependent. There is a strong need for standardization of blood sample collection and processing in tHcy and other thiols assays. The plasma concentrations of tHcy, tCys, tCysGly and tGSH were stable for 3 h at least in the EDTA-3DA and EDTA-NaF tubes kept at room temperature.

Objective To investigate the tryptophan (Trp) metabolism change in the patients with chronic hepatitis B (CHB) and hepatitis B cirrhosis (HBC) and to analyze the related risk .Methods Eighty-one cases of CHB and 40 cases of HBC hospitalized in the First Affiliated Hospital of Chongqing Medical University from October 2015 to January 2016 served as the stud-y subjects ,and 40 healthy persons as the controls .High performance liquid chromatography -fluorescence detection (HPLC-FD) were adopted to detect the levels of plasma Trp ,kynurenine (Kyp) and its metabolite 5-hydroxy tryptamine (5-HT) .HBV-DNA vi-ral replication number was detected by real-time quantitative PCR .The serological indicators differences among 3 groups were ana-lyzed .The risk factors were analyzed and screened by the Logistic regression analysis and Pearson correlation analysis .Results Compared with the control group ,plasma 5-HT and Trp levels in the CHB group and HBC group were significantly decreased (P<0 .01);plasma Kyn/Trp in the HBC group was significantly higher than that in the other two groups (P<0 .01) .Kyn/Trp in the HBC group was negatively correlated with A/G (r= -0 .686 ,P<0 .01) ,and Kyn/Trp in the CHB group was positively correlated with Log DNA (r= 0 .784 ,P<0 .01) .The Logistic regression analysis indicated that Kyn/Trp was the risk factor of CHB and HBC .Conclusion Detecting plasma Trp and its metabolite can serve as the adjuvant indicators for assessing the progression of hep-atitis B .