Irradiation of pyrimidine in pure H2O ice with high-energy ultraviolet photons.

The detection of nucleobases, the informational subunits of DNA and RNA, in several meteorites suggests that these compounds of biological interest were formed via astrophysical, abiotic processes. This hypothesis is in agreement with recent laboratory studies of irradiation of pyrimidine in H2O-rich ices with vacuum UV photons emitted by an H2-discharge lamp in the 6.9-11.3 eV (110-180 nm) range at low temperature, shown to lead to the abiotic formation of several compounds including the nucleobases uracil, cytosine, and thymine. In this work, we irradiated H2O:pyrimidine ice mixtures under astrophysically relevant conditions (14 K, ≤10(-9) torr) with high-energy UV photons provided by a synchrotron source in three different ranges: the 0(th) order light (4.1-49.6 eV, 25-300 nm), the He i line (21.2 eV, 58.4 nm), and the He ii line (40.8 eV, 30.4 nm). The photodestruction of pyrimidine was monitored with IR spectroscopy, and the samples recovered at room temperature were analyzed with liquid and gas chromatographies. Uracil and its precursor 4(3H)-pyrimidone were found in all samples, with absolute and relative abundances varying significantly from one sample to another. These results support a scenario in which compounds of biological interest can be formed and survive in environments subjected to high-energy UV radiation fields.

Early elevated HMGB1 level predicting the outcome in exertional heatstroke.

BACKGROUND: Heatstroke is generally considered as a syndrome of hyperthermia associated with systemic inflammation leading to multiorgan dysfunction. High mobility group box-1 protein (HMGB1) has recently been identified as a late mediator of systemic inflammation inducing multiorgan dysfunction. Elevation of plasma HMGB1 in heatstroke has been observed in animals, but there is no data available about its changes in heatstroke patients. The objectives of this study are to observe the time course of plasma HMGB1 changes and assess its prognostic value in patients with exertional heatstroke. METHODS: Blood samples were taken from the patients with exertional heatstroke. Plasma HMGB1 level was detected by the enzyme-linked immunosorbent assay. C-reactive protein level was measured using a fully automated IMMAGE Immunochemistry System. Secreted HMGB1 in the culture supernatant of peripheral blood monocyte was assessed by immunoblotting. Acute Physiology and Chronic Health Evaluation II score was evaluated within 24 hours of admission. RESULTS: HMGB1 released into circulation at early stage, with peak levels occurring within 6 hours to 13 hours postheatstroke. Plasma HMGB1 levels remained markedly elevated in the following 6 days postheatstroke when compared with healthy volunteers (p<0.005). Positive correlation (r=0.798, p<0.001) was found between Acute Physiology and Chronic Health Evaluation II score and HMGB1 level at admission. HMGB1 levels at admission between survivors and nonsurvivors were significantly different (p<0.001). Receiver operating curve analysis showed that at a level of 47 ng/mL, HMGB1 level at admission indicated lethality with 77.4% sensitivity and 84.2% specificity. CONCLUSIONS: HMGB1 level at admission is an indicator of the severity of illness and a useful mortality predictor in exertional heatstroke.

[Role of assessment and monitoring of human leucocyte antigen-DR on CD14+ monocyte in postoperative infection in patients after orthotopic liver transplantation].

OBJECTIVE: To investigate the changes in expression level of human leucocyte antigen-DR (HLA-DR) on CD14(+) monocyte (CD14(+)/HLA-DR) in the patients after orthotopic liver transplantation, and its role in monitoring postoperative infection. METHODS: Sixty-three patients with liver transplantation were divided into three groups, non-infection group with 47 cases, infection group with 10 cases and septic shock group with 6 cases [according to the definition of septic shock of American College of Chest Physicians/Society for Critical Care Medicine (ACCP/SCCM)]. CD14(+)/HLA-DR expression ratio was assessed with flow cytometer, and its clinical implication was evaluated by receiver operating characteristic (ROC) curve assay. RESULTS: CD14(+)/HLA-DR expression ratio in infection group [(29.6+/-7.2)%] and septic shock group [(16.3+/-10.5)%] were significantly lower than that in non-infection group [(62.3+/-18.3)%, both P<0.01], but no significant difference of CD14(+)/HLA-DR expression ratio was found between infection group and septic shock group (P=0.128). Total area under ROC curve of CD14(+)/HLA-DR expression ratio for the infection was 0.965, its sensitivity and specificity at 36.35% cut off were 100.0% and 93.6%, respectively. Total area under ROC curve of CD14(+)/HLA-DR expression ratio to predict septic shock was 0.968, its sensitivity and specificity at 31.97% cut off were 100.0% and 87.7%, respectively. Comparing the change of CD14(+)/HLA-DR expression, it was lower in the infection group and septic shock group (P<0.05 and P<0.01), and the expression rate was lowest during period of serious infection in the two groups [infection group: (29.6+/-7.2)%, septic shock group: (16.3+/-0.5)%, all P<0.01]. CONCLUSION: For the patients with possible infection after liver transplantation, sequential assessment of CD14(+)/HLA-DR expression ratio would be a good marker for the judgment of patient's conditions and outcome. CD14(+)/HLA-DR expression ratio below 36.35% could be used as the prewarning value for the diagnosis of postoperative infection, and 31.97% could be used as the critical value for the diagnosis of septic shock.