ABSTRACT
Objective:The hemolytic prediction model of the axial flow impeller blood pump is carried out by using a computational fluid dynamics(CFD) multiphase flow model.Methods:The hydrodynamic performance of the pump and the flow field in the pump, and the shear stress distribution are analyzed. A hemolytic prediction model based on the shear stress is built based on the calculation results. Hemolysis tests in vitro were performed 6 times with fresh bovine blood. At each time, the flow of the ventricular assist device(VAD) is 5 L/min and the outflow tract pressure is 100 mmHg(13.3kPa). According to the tests, the plasma free hemoglobin(FHB) content and the hematocrit(HCT) are measured every half hour. At the end of each experiment Normal Index of Hemolysis(NIH) is calculated.Results:The average of NIH is 0.0055 g/100L, almost identical with that obtained from the hemolytic prediction model.Conclusion:Multiphase flow model can be used for quantitative predictions of the hemolytic behavior of a VAD. This method can be applied in the selection stage of a blood pump.
ABSTRACT
<p><b>OBJECTIVE</b>To improve the MigR1-CD19-CAR (chimeric antigen receptor) that contains a single chain variable region (scFv) which targeted to CD19 through a retroviral vector transduction efficiency of T-lymphocytes.</p><p><b>METHODS</b>Insert the CD19-CAR fragment into the retroviral vector (MigR1) through recombinant DNA technology, after transfecting plat-A packaging cell lines, viral supernatant was collected to transduce K562 cell line and activated human T-lymphocytes. We used flow cytometry to determine the transduction efficiency and RT-PCR to confirm the transcription of CD19-CAR gene. The ability of the transduced T cells to produce IFN-γ and TNF-α in a CD19-specific manner was measured in an enzyme-linked immunosorbent (ELISA) assay.</p><p><b>RESULTS</b>(1)Using MigR1-CD19-CAR retroviral vector to produce the high titer retrovirus. (2)MigR1-CD19-CAR transduction efficiency of K562 cell line was significantly higher than human T-lymphocytes (P<0.01). (3)120 min centrifugation could significantly improve transduction efficiency of T-lymphocytes to (54.5±14.6)%. (4)Transduction efficiency could be improved by deciding transduce time according to T-lymphocytes proliferation fold in vitro individually, and the highest transduction efficiency in the study was 69.3%. The CD19-CAR gene sequence was transcripted specificly with high efficiency. (5) IFN-γ and TNF-α released by CD19-CAR transduced T-lymphocytes significantly increased to (13 230±1 543) pg/ml and (4 217±211) pg/ml when coculture with CD19-K562 cells.</p><p><b>CONCLUSION</b>We have successfully constructed a second generation CAR which targeted to CD19 through a retroviral vector called MigR1 (MigR1-CD19-CAR). Deciding transduce time according to T-lymphocytes proliferation fold in vitro individually and 120 min centrifugation could improve the CAR transduction efficiency of T-lymphocytes. RT-PCR confirmed that the CD19-CAR gene was specificly transcripted with high efficiency. IFN-γ and TNF-α released by CD19-CAR transduced T-lymphocytes significantly increased when activated by target cells.</p>
Subject(s)
Humans , Antigens, CD19 , Cell Proliferation , Flow Cytometry , Genetic Vectors , K562 Cells , Recoverin , Retroviridae , T-Lymphocytes , TransfectionABSTRACT
Objective To compare the therapeutic effect of inhaled aerosolized and intravenous milrinone,a phosphodiesterase-3 inhibitor in rats with oleic acid-induced acute lung injury (ALI) .Methods Forty male SD rats weighing 300-350 g were randomly divided into 4 groups (n=10 each) : group Ⅰ normal control: group Ⅱ ALI; group Ⅲ milfinone inhalation and group Ⅳ intravenous milrinone.The animals were anesthetized with intraperitoneal 2% pentobarbital 40 mg/kg,tracheostomized and mechanically ventilated (FiO2 30%,VT 10 ml/kg,RR 80 bpm,I:E=1:2).The chest was opened and the heart was exposed.Pulmonary artery was catheterized via fight ventricle.MAP,CVP,airway pressure and pulmonary artery pressure (PAP) were monitored.ALI was induced with 10% oleic acid 2 ml/kg administered through fight external jugular vein in group Ⅱ,Ⅲ and Ⅳ.In control group 0.1% BSA solution 2 ml/kg was administered iv instead of oleic acid.In group Ⅲ at 30 min after oleic acid administration aerosolized milrinone 1 mg/ml was inhaled 4 times at 60 min interval.Each time milrinone was inhaled for 10 min.In group Ⅳ at 30 min after oleic acid administration a bolus of 10 μg/kg milrinone was given iv followed by 10 min milrinone infusion at 1 μ·kg-1·min-1.The same procedure was repeated 4 times at 60 min interval.MAP and PAP were recorded and blood samples were taken from carotid artery and pulmonary artery for blood gas analysis at the 1st,2nd,3rd and 4th treatment.PaO2/FiO2 and Qs/Qt were calculated.The animals were sacrificed by exsanguination after the 4th treatment.The lungs were removed.The left lung was lavaged.Neutrophil count and protein content in broncho-alveolar lavage fluid (BALF) were determined.W/D lung weight ratio and lung myeloperoxidase (MPO) activity were measured.The uhrastructure of the lung was examined with electron microscope.Results The MAP was significantly lower after oleic acid adminstration in group Ⅳ than in other 3 groups.PaO2/FiO2 was significantly decreased and Qs/Qt increased by iv oleic acid in group Ⅱ ,Ⅲ and Ⅳ.PAP was significantly increased after iv oleic acid in group Ⅱ ,Ⅲ and Ⅳ but was significantly lower in group Ⅲ and Ⅳ than in group Ⅱ .The neutrophil count and total protein content in BALF,W/D ratio and lung MPO activity were significantly increased in group Ⅱ ,Ⅲ and Ⅳ as compared with control group(Ⅰ) and were significantly higher in group Ⅳ than in group Ⅲ.The lung damage induced by oleic acid was less serious in group Ⅲ and Ⅳ than in group Ⅱ .Conclusion Inhaled aerosoLized milrinone has better therapeutic effect than intravenous milrinone in rats with oleic acid-induced ALI and is safer.