Key Preparation Technique and Clinical Application of Frozen Platelets / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To explore the key technique for preparation of the frozen platelet and efficacy of its clinical application.</p><p><b>METHODS</b>The influences of the donators' peripheral platelet count, starting time of freeze, injection rate and evenness of the freeze-protective agent, storage mode, re-melting temperature and the capacity of water-bath etc. on the quality of the frozen platelets were analyzed retrospectively in 3 257 samples of frozen platelets before platelet pheresis. Then, the platelet counts were examined in 150 cases transfused with frozen platelets at the time-points of 1, 24, 48 and 72 hrs after transfusion, 90 cases suffered from the obstetrical bleeding were transfused with 200 parts of the re-melting frozen platelets, and then the peripheral blood platelet count, platelet increasing index(CCI), bleeding time and blood clot retraction rate etc. were observed for determining the clinical efficiency of the frozen platelets.</p><p><b>RESULTS</b>The floccule in the re-melting frozen platelets from the donators with (175-250)×10(9)/L platelets were decreased significantly(P<0.01). The quality of frozen platelets was influenced by the following factors, such as injection of DMSO at a too fast and heterogeneous rate, blood bags stored in a multilamminar space, and re-melting in a water-bath of small capacity etc. The routine storage for 0 and 3 days did not influence the quality of the frozen platelets. The recovery rate of one year-freezing platelets all was higher than 80%. The effects of the frozen platelets transfused into the patients with obstetrical bleeding displayed good haemostatic results, and the blood transfusion reaction did not occur. However, the frozen platelets immediately were exhausted and displayed their function, but the counting after 48 hrs could not display a good effect of raising platelet number.</p><p><b>CONCLUSIONS</b>The peripheral platelet count before platelet pheresis, the injection rate and evenness of the protective agent, the number of stratum for blood bags and the capacity of re-melting water-bath etc. all are the key factors influencing the quality of the frozen platelets. The frozen platelets prepared in this study shows a good efficacy of clinical application.</p>

Further characterization of o-nitrobenzaldehyde degrading bacterium Pseudomonas sp: ONBA-17 and deduction on its metabolic pathway

A previously reported o-nitrobenzaldehyde (ONBA) degrading bacterium Pseudomonas sp. ONBA-17 was further identified and characterized. Based on results of DNA base composition and DNA-DNA hybridization, the strain was identified as P. putida. Its degradation effect enhanced with increase of inoculum amount and no lag phase was observed. Higher removal rate was achieved under shaking conditions. All tested ONBA with different initial concentrations could be completely degraded within 5 d. In addition, degradative enzyme(s) involved was confirmed as intra-cellular distributed and constitutively expressed. Effects of different compounds on relative activity of degradative enzyme(s) within cell-free extract were also evaluated. Finally, 2-nitrobenzoic acid and 2, 3-dihydroxybenzoic acid were detected as metabolites of ONBA degradation by P. putida ONBA-17, and relevant metabolic pathway was preliminary proposed. This study might help with future research in better understanding of nitroaromatics biodegradation.