Efficacy and safety evaluation of a novel domestic extracorporeal membrane oxygenation mainframe / 中华急诊医学杂志

Objective:To evaluate the safety and efficacy of a novel domestic extracorporeal membrane oxygenation (ECMO) mainframe in a porcine model, and to provide the basis for further clinical application.Methods:Five domestic healthy male white pigs, weighing (51±4) kg, were selected. The ECMO system was established by using a novel ECMO mainframe with imported membrane oxygenator and pipeline, and continued to run for 72 hours. ECMO parameters are as follows: veno-arterial ECMO, centrifugal pump speed 3 000-3 500 r/min, continuous infusion of heparin anticoagulation to maintain the activate clotting time (ACT) of 140-200 s. Real-time monitoring of speed, flow, pressure before pump, pressure after pump, pressure after membrane and other equipment parameters, and the equipment performance was scored. The changes of hemodynamics, blood lactic acid and blood routine were monitored dynamically. Repeated measures analysis of variance was used to compare different time points within the group. At the end of the experiment, the thrombosis in the pump head and oxygenator was observed. The animals were sacrificed to obtain the tissue samples of the main organs for gross observation and pathological injury evaluation.Results:All animals successfully ran the ECMO system for 72 hours. (1) The centrifugal pump speed should be maintained at 3 029-3 483 r/min, the flow rate was maintained at 2.24-2.60 L/min, The pressure before the pump between minus 107.57 and minus 31.86 mmHg, the pressure after the pump was 197.50-282.43 mmHg, and the pressure after the membrane was 178.71-261.5 mmHg, all were in the normal range, and there was no significant difference between different time points (all P>0.05). The performance scores of the mainframe were all 4 points or above, indicating that the use requirements were met. (2) The heart rate of the animals was 50-80 beats /min, the mean arterial pressure was 85-115 mmHg, and the lactic acid was 0.996-2.25 mmol/L, all within the normal range, and there was no significant difference between different time points (all P>0.05). The free hemoglobin was 8.98-16.39 mg/L, and the hemoglobin was 6.58-7.52 g/L, both within a reasonable range, and there was no significant difference between different time points (all P>0.05). The platelet count was 69.6-231.6×10 9/L, and showed a continuous downward trend ( P<0.05). ACT was maintained at 135-169 s, which was within the target range, and there was no significant difference between different time points ( P<0.05). (3) At the end of the experiment, there was no obvious thrombosis in the pump head and oxygenator, no obvious thrombosis or infarction in the heart, brain, liver, lung and kidney, and no obvious hemorrhage or necrosis under the microscope. Conclusions:The ECMO established by the novel domestic ECMO mainframe combined with imported membrane oxygenator and pipeline ran smoothly for 72 hours, achieving the target of effect and safety.

Progress and technology development on hydrogen production through bioconversion of lignocellulosic biomass / 生物工程学报

Hydrogen production from lignocellulosic biomass is both sustainable and environmentally friendly, which is garnering more and more attention across the world, with an expectation to challenge the shortage of fossil fuels supply and climate change as well. In this article, the update research progress and technology development of biohydrogen production are reviewed, with a focus on biomass pretreatment, hydrogen-producing microorganisms and process engineering strategies. And in the meantime, a roadmap for more efficient and economic biohydrogen production is envisioned.

Expression of hGM-CSF in transformed silkworm BmN cells mediated by non-transposon vector / 生物工程学报

To develop the stable transformants of the silkworm (Bombyx mori) BmN cells that could continuously express the exogenous gene based on a non-transposon vector, an expression cassette containing human granucyto-macrophage colony-stimulating factor (hGM-CSF) gene driven by ie-1 promoter from B. mori nucleopolyhedrovirus was inserted into pIZT-V5-His to form a recombinant vector pIZT-IE-hGM-CSF, followed by transfecting the constructant into BmN cells, the stable ie-hGM-CSF cell lines were obtained after being selected with Zeocin. PCR result using the genomic DNA of the transformed BmN cells as template illustrated a specific fragment of ie-hGM-CSF, and Western blotting analysis using an antibody against hGM-CSF demonstrated a specific band with a molecular weight of 22 kDa in the transformed cells, meanwhile, the expression level of hGM-CSF determined by ELISA was about 2 814.7 pg in 10(6) transformed BmN cells.

Transiently secretory expression of DsRed driven by fibroin heavy chain promoter of Bombyx mori / 生物工程学报

Based on the character of strong promoter of the fibroin gene and high level secretion of fibroin of Bombyx mori, we amplified the promoter of heavy chain gene (Fib-H) and its downstream signal peptide sequence (FibHS) by PCR. After that, we cloned the PCR product in pBluescriptII SK (+) to form the vector pSK-FibHS and analyzed its sequence. The sequence identity was 99% comparable to that of the reported sequence by Blast on line. Then we digested pSk-Ser-DsRed-PolyA with Sal IKpn I to get DsRed-PolyA DNA fragment and subcloned it into vector pSK-FibHS to generate a transitorily secretory expression vector pSK-FibHS-DsRed-PolyA. After identified the recombinant plasmid by restriction enzyme digestion, we transfected pSK-FibHS-DsRed-PolyA into BmN cells by liposome. From the cells transfected with the recombinant vector, what the red fluorescence could be detected verified that the recombinant vector could express DsRed in BmN cells transiently. Furthermore, when silkworm had been injected with the recombinant vector pSK-FibHS-DsRed-PolyA, red fluorescence could be observed in the lumen of silk gland of silkworm. The result indicated that DsRed expressed transiently and was secreted into lumen of the silk gland. Therefore, we supposed that the cloned sequence (FibHS) possessed signal peptide bio-function. Moreover, this study would lay a foundation for the research on secretory expression of exogenous gene by silk gland bioreactor.