Research on coronavirus disease 2019 (COVID-19) detection method based on depthwise separable DenseNet in chest X-ray images / 生物医学工程学杂志

Coronavirus disease 2019 (COVID-19) has spread rapidly around the world. In order to diagnose COVID-19 more quickly, in this paper, a depthwise separable DenseNet was proposed. The paper constructed a deep learning model with 2 905 chest X-ray images as experimental dataset. In order to enhance the contrast, the contrast limited adaptive histogram equalization (CLAHE) algorithm was used to preprocess the X-ray image before network training, then the images were put into the training network and the parameters of the network were adjusted to the optimal. Meanwhile, Leaky ReLU was selected as the activation function. VGG16, ResNet18, ResNet34, DenseNet121 and SDenseNet models were used to compare with the model proposed in this paper. Compared with ResNet34, the proposed classification model of pneumonia had improved 2.0%, 2.3% and 1.5% in accuracy, sensitivity and specificity respectively. Compared with the SDenseNet network without depthwise separable convolution, number of parameters of the proposed model was reduced by 43.9%, but the classification effect did not decrease. It can be found that the proposed DWSDenseNet has a good classification effect on the COVID-19 chest X-ray images dataset. Under the condition of ensuring the accuracy as much as possible, the depthwise separable convolution can effectively reduce number of parameters of the model.

Differentiation of dendritic cells in monocyte cultures isolated from patients with unstable angina.

OBJECTIVE: Dendritic cells (DC) stimulate T-cell proliferation and activation in the course of adaptive immunity. Its role in unstable coronary plaque in humans is unknown. So we investigated the functional role of DC in patients with unstable angina pectoris (US) using human monocyte-derived DC. METHODS: Twenty milliliters of blood was drawn from the femoral artery of 20 patients, who underwent coronary angiography. Ten patients with a diagnosis of US and 10 patients with normal CAG were included in the observation and control groups, respectively. The mononuclear cells were separated from the peripheral blood and cultured in RPMI1640 with supplement of rh GM-CSF and rh IL-4 to induce DC. The shape and ultrastructure of DC was analyzed with electronic microscopy. The phenotype of DC was analyzed with FACS and the alloantigen presenting capacity of DC was evaluated by mixed lymphocyte reaction (MLR). The levels of cytokines in allogenic DC/T cell cultures were assayed by ELISA. RESULTS: The expression rate of CD86 in patients with US was 30.8+/-3.3%, which was obviously higher than that of normal DC (19.4+/-3.0%), P<0.001. The capacity of proliferation of patients DC to induce allogenic T cells (OD 1.82+/-1.29), which was obviously higher than that of the normal DC (OD 0.81+/-0.41), P<0.005. TNF-alpha (40.05+/-7.15 pg/ml), IL-1beta (19.01+/-1.39 pg/ml) and IL-6 (40.80+/-16.04 pg/ml), produced during MLR were higher in patients with US than that of normal patients 7.85+/-1.10, 12.18+/-1.93 and 19.55+/-0.7, respectively, P<0.05. IL-10 (10.94+/-0.56 pg/ml) produced during MLR was lower in patients with US than that of normal patients (16.63+/-3.40 pg/ml), P<0.05. CONCLUSION: Our results suggest that the function of DC in patients with US is increased and these activated effects of DC may play a primary role in the immune process of plaque rupture.

The cardiac function effect of allopurinol for hyperuricemia combined with dilated cardiomyopathy patients / 中国医师进修杂志

Objective To study the cardiac function effect of allopurinol for hypemricemia combined with dilated cardiomyopathy patients.Methods One hundred and twenty hypemricemia combined with dilated cardiomyopathy patients were divided into allopurinol group and control group according to the treatment method with 60 cases each.All the patients were given conventional treatment,the control group was added the nitroprusside treatment,and the allopurinol group was added the allopurinol and nitroprusside treatment.The treatment period was 3 months.Results The total effective rate in allopurinol group was significantly higher than that in control group [90.0％ (54/60) vs.75.0％ (45/60)],there was statistical difference (P ＜ 0.05).After treatment,the left ventricular ejection fraction and left ventricular posterior wall thickness at end-systole in allopurinol group were significantly higher than those in control group [(67.85 ± 7.12)％ vs.(30.78 ±7.00)％ and (1.40 ±0.20) mm vs.(1.16 ±0.18) mm[,but the left ventricular internal diameter at end-systole,left ventricular internal diameter at end-diastole and left ventricular posterior wall thickness at end-diastole were significantly lower than those in control group [(4.72 ± 0.41) mm vs.(6.48 ± 0.47) mm,(2.93 ± 0.32) mm vs.(5.56 ± 0.62) mm and (0.77 ± 0.13) mm vs.(0.92 ± 0.18) mm],there were statistical differences (P ＜ 0.05).After treatment,The uric acid,urea nitrogen and creatinine were significantly lower than those in control group [(45.43 ± 11.24) μ mol/L vs.(167.23 ± 19.22) μ mol/L,(10.23 ± 7.12)mmol/L vs.(40.93 ± 8.09)mmol/L and (32.01 ± 8.34) mmol/L vs.(78.09 ±9.11) mmol/L],there were statistical differences (P ＜ 0.05).Conclusion Allopurinol used for treating hyperuricemia combined with dilated cardiomyopathy patients can reduce uric acid,early reversal the atherosclerosis and improve heart function,it should be widely applied research.

Cardiomyocyte hypertrophy induced by PGF2α / 中国医师杂志

Objecave The effects of PGF2α on the reactive oxygen species generation and cardiomyocyte hypertrophy were examined in experiments on the cultured neonatal rat cardiomyocytes.It is to study the role of ROS in the signaling pathway of cardiomyocyte hypertrophy induced by PGF2α.Methods The level of intracellular ROS wag measured by the ROS-specific probe 2',7'-dichlorofluorescin diacetate (DCF-DA).Cardiomyocyte hypertrophy was determined by total protein content of the cells and the cell diameter.Results In the cardiomyocytes treated with PGF2α(1nmol/l,10nmol/l,100nmol/l),the fluorescence intensity of intracellular DCF-DA increased by 38.99%,61.76% and 93.55% respectively compared with control group(F=195.69,P＜0.01).It is indicated that PGF2α can induce intracellular ROS generation on the cultured neonatal rat cardiomyocytes in a dose-dependent manner.Compared with control group,the total protein increased by 39.51%, 69.93%and 139.06%respectively(F=74.014,P＜0.01),and the cell diameter increased by 29.02%,60.79%and 127.40%respectively(F=721.02,P＜0.01).It is indicated that PGF2α induce cardiomyocyte hypertrophy on the cultured neonatal rat cardiomyocytes in a dose-dependent manner.Conclusion PGF2α can induce intracellular ROS generation and cardiomyocyte hypertrophy on the cultured neonatal rat cardiomyocytes in a dose-dependent manner.

Effect of Extract of Ginkgo Biloba(EGb)on Cell of Neonatal Rat Cardiocyte Hypertrophy Induced by Prostaglandin F2 Alpha / 医学研究杂志

Objective To investigate the effects and mechanisms of extract of ginkgo biloba(EGb)on the cell of cardiocyte hypertrophy induced by prostaglandin F2 alpha.Methods normal cells were used as negative control,and spontaneously PGF2? and EGb were used as experimental groups.The cells were isolated and cultured on cultured neonatal rat cardiocyte by PGF2?,cardiocyte hypertrophy was determined by the cell surface and the total protein of cells;the level of intracellular ROS measured by the fluorescence microscope.Results In cardiocyte hypertrophy,the cell surface,the level of intracellular ROS and the total protein of cells increased significantly in cutured neonatal rat cardiac treated with PGF2?.Compared with cells treated with PGF2?,EGb(40?g/ml,80?g/ml,100?g/ml)inhibited cardiocyte hypertrophy by PGF2?-induced,decreased in the cell surface by 19%,27%,33% and in the total protein of cells by 21%,39%,47% respectively(all P

Dynamic model of neointima proliferation and remoulding of vascular wall after common carotid artery denudated in rabbits / 中国医师杂志

Objective To study the mechanism of restenosis following percutaneous transluminal coronary angioplasty(PTCA),and to replicate a dynamic model of cell proliferation and remoulding of vascular wall at different time points in rabbits after intimal injury.Methods The model of restenosis in common carotid artery was established by balloon injury in 70 rabbits.The indexes such as lumen area,thickness and area of intima and media,and cross sectional area bounded by the external elastic lamina(EELA) were respectively measured by computer image analysis technology at the 1st,3rd,5th, 7th,14th,28th and 35th day after the injury.Results Endothelial cells were denudated at the 1st day after injury.The proliferation of vascular smooth muscle cell(VSMC) was detected on the surface of lumen at 3 days after injury.At the 7th day after injury,the neointima was formed and continuously thicken.The thickness and area of the neointima as well as extracellular matrix were gradually increased after 14 days,and were maximal after 35 days.The thickness and area of media were also gradually increased during 3～14 days and decreased after 28 days.Compared with non-injured vessel,the medial area was obviously increased at the 14th day.The lumen area was decreased at the 5th～7th day after injury and was obviously less than that of non~injured vessel after 14 days.The EELA was gradually increased at the 1st～7th day after injury,and reached its maximum at the 14th day.The EELA was declined gradually after 28 days.Conclusion The progress of restenosis(RS) can be simulated through the model of restenosis in common carotid artery of rabbit established by balloon injury.The intimal proliferation and vascular remodeling are the leading pathogenesis of restenosis.