Electrocardiogram signal classification algorithm of nested long short-term memory network based on focal loss function / 生物医学工程学杂志

Electrocardiogram (ECG) can visually reflect the physiological electrical activity of human heart, which is important in the field of arrhythmia detection and classification. To address the negative effect of label imbalance in ECG data on arrhythmia classification, this paper proposes a nested long short-term memory network (NLSTM) model for unbalanced ECG signal classification. The NLSTM is built to learn and memorize the temporal characteristics in complex signals, and the focal loss function is used to reduce the weights of easily identifiable samples. Then the residual attention mechanism is used to modify the assigned weights according to the importance of sample characteristic to solve the sample imbalance problem. Then the synthetic minority over-sampling technique is used to perform a simple manual oversampling process on the Massachusetts institute of technology and Beth Israel hospital arrhythmia (MIT-BIH-AR) database to further increase the classification accuracy of the model. Finally, the MIT-BIH arrhythmia database is applied to experimentally verify the above algorithms. The experimental results show that the proposed method can effectively solve the issues of imbalanced samples and unremarkable features in ECG signals, and the overall accuracy of the model reaches 98.34%. It also significantly improves the recognition and classification of minority samples and has provided a new feasible method for ECG-assisted diagnosis, which has practical application significance.

A Study on the Practicability and Influencing Factors of the Frailty Assessment in Elderly Patients with Coronary Atherosclerotic Heart Disease / 现代生物医学进展

Objective:To investigate the correlation and influence factors of three weak assessment scales in the evaluation of debilitating condition of elderly patients with coronary heart disease (CHD).Methods:120 cases with CHD in our hospital were chosen,the clinical material were collected.The Fried weak score,clinical weak score and EFS were assessed.The correlation of three weak assessment scales were analyzed.Results:Fried score,CFS score and EFS score determined 6 cases,8 cases and 14 cases patients with weak respectively,the incidence rate were 5.0％,6.7％ and 11.7％,which had no significant difference(P＞0.05).The linear correlation analysis indicated the Fried score,CFS score and EFS score had positive correlation(P＜0.05),which had consistency with CHD patients.The CFS score and EFS score had no significant correlation (P＞0.05).Cox regression analysis showed that the cultural level and grade of cardiac function,living conditions and sleep disorders were influencing factors of Fried scores(P＜0.05).Conclusion:Three weak assessment had consistence and different clinical value for the evaluation of weakness in CHD patients,the cultural level and grade of cardiac function,living conditions and sleep disorders were influencing factors of weakness in CHD patients.

Effects of Exogenous Nerve Growth Factor on Late Reperfusion after Myocardial Infarction / 生物医学工程学杂志

This study demonstrates that nerve growth factor (NGF) plays a protective role in myocardial infarction and early reperfusion by reducing the myocardial cell apoptosis and by improving ventricular remodeling and seeks to assess the effects and mechanisms of NGF on late reperfusion after myocardial infarction. The models of late reperfusion were established by ligating the left main coronary artery and then cutting the suture 2 hours after coronary artery ligation. The rats in NGF treatment group were injected 10 µL Ad-NGF (by constructing the adenovirus vector Ad-NGF containing NGF gene) at four locations around infarction. The rats in adenoviral vector (Adv) group were injected 10 µL adenoviral cector as the NGF group. The late reperfusion group and the sham group were given normal saline as above, and the sham group underwent thracotomy without coronary ligation. On the 3rd, 7th, 14th and 28th day after operation, we investigated the role of NGF on late reperfusion by recording cardiac structure and function with echocardiography, by examining the expression of NGF and VIII factor with immunohistochemical method, and by evaluating the myocardial cell apoptosis with terminal dUTP nick end-labeling method (TUNEL). We found that the NGF group had higher expression of NGF protein (P < 0.01) and lower apoptosis index (AI) (P < 0.01 or P < 0.05) compared to the late reperfusion group and Adv group on all time points. The NGF group had remarkably higher level of neovascularization compared to the late reperfusion group on the 14th day (P < 0.01) and the 28th day (P < 0.05). The NGF group also had higher LVEF and FS levels compared to the late reperfusion group on the 14th day (P = 0.006, P = 0.006) and on the 28th day (P = 0.000, P = 0.000). Whereas the NGF group had lower LVEDD, LVESD (P = 0.038, P = 0.000) and lower LVEDV, LVESV (P = 0.001, P = 0.000) on the 28th day compared to late reperfusion group. In this experiment, the NGF gene carried by adenovirus vector had been transfected and obviously increased the expression of NGF protein in NGF group. NGF may help postpone the myocardial remodeling and improve the heart function by promoting the myocardial neovascularization and inhibiting myocardial apoptosis.

Study on the action mechanism of basic fibroblast growth factor on vascular smooth muscle cells in spontaneously hypertensive rats / 中华老年医学杂志

Objective To explore the action mechanism of basic fibroblast growth factor (bFGF) on vascular smooth muscle cells (VSMCs) in spontaneously hypertensive rats (SHR).Methods Ts were obtained from SHR and SD rats.The aortic VSMCs were cultured in vitro by tissue explant method.VSMCs were treated with different concentration of exogenous bFGF (0 ng/ml,20 ng/ml,40 ng/ml,60 ng/ml,80 ng/ml,100 ng/ml) for 48 h,then cell proliferation was detected by 3 (4,5 dimethylthiazol)2,5 diphenyltetrazolium bromide (MTT) colorimetric assay.VSMCs from SHR in control group were treated with bFGF (100 ng/ml) for 48h.VSMCs from SHR in treatment group were treated with bFGF (100 ng/ml) plus Proteinkinase C(PKC) inhibitor (staurosporine) for 48 h.Results After treatment with different concentration (0 ng/ml,20 ng/ml,40 ng/ml,60 ng/ml,80 ng/ml,100 ng/ml) of bFGF for 48 h,the values measured by MTT colorimetric method were 0.402 ± 0.103,0.605 ±0.090,0.696 ± 0.131,0.812 ± 0.080,0.901 ± 0.065,1.056±0.078 respectively in aortic VSMCs from SD rats,and 0.404±0.065,0.507±0.078,0.608±0.057,0.704 ± 0.107,0.812 ± 0.097,0.908 ± 0.032 respectively in aortic VSMCs from SHR.Compared with control group,the values measured by MTT colorimetric method were decreased in treatment group (P＜0.05).The proliferative effect of bFGF in aortic VSMCs from SHR was attenuated after administration of PKC inhibitor staurosporine.Conclusions Exogenous bFGF administration promotes VSMCs proliferation in SHR and SD rats in a concentration-dependent manner.PKC plays an important role in the signal transduction mechanism in VSMCs proliferation by exogenous bFGF.

Biological characteristics of glucose-responsive microcapsules carrying beta-TC3 cells / 中国组织工程研究

BACKGROUND:To prepare glucose-responsive microcapsules which can control insulin release as changing the glucose concentration in the medium is of great significance to control the occurrence and development of diabetes mel itus. OBJECTIVE:To study the performance of glucose-responsive alginate/modified-chitosan/alginate microcapsules carryingβ-TC3 cells. METHODS:Glucose-responsive alginate/modified-chitosan/alginate microcapsules were prepared by layer-by-layer self-assembly method to evaluate the performance. And the glucose-responsive microcapsules carryingβ-TC3 cells were prepared to observe the cel proliferation within the microcapsules. RESULTS AND CONCLUSION:The integrity rate of glucose-responsive alginate/modified-chitosan/alginate microcapsules could be 95%after 48 hours oscil ation, and the hardness of microcapsules lowered, but the elasticity increased. The permeability test showed that microcapsules intercepted macromolecular substances such as bovine serum albumin and immuno-globulin G. The microcapsules could release more insulin with the increase of glucose concentration. As described above, the glucose-responsive alginate/modified-chitosan/alginate microcapsules had good mechanical strength, immunoisolation effect and glucose sensitivity. Theβ-TC3 cells entrapped in the glucose-responsive microcapsules could grow wel and the peak of cel proliferation lagged behind as compared with non-microencapsulated cells, indicating the glucose-responsive microcapsules had good biocompatibility.

Influence of T- and B-cell-deficiency on retinal neurocytes of mice withacute ocular hypertension / 眼科研究

Background Recently,the study on the cause of optic nerve damage induced by glaucoma is of concern in ophthalmology.Some research showed that the immune system is associated with glaucoma-induced optic neuropathy.Acute ischemia-reperfusion is an ideal model of studying optic neuropathy.ObjectiveThe present study investigates the effect of T and B lymphocyte deficiency on the retinal neurocytes of mice with acute intraocular hypertension.Methods Sixteen SPF CB-17/Icr.Cg-Prkdc~(scid)Lyst~(bg)/CrlVR mice 6-8 week-old (severe combined immunodeficiency mouse,SCID) were used in this study and 16 age-matched SPF wild type (C57BL/6) mice served as controls.The ischemia-reperfusion injury models were induced in the right eyes of 10 SCID mice and 10 C57BL/6 mice through intra-anterior chamber infusion of balanced saline solution for 45minutes to increase the intraocular pressure to 104mmHg,and the left eyes served as model controls.The other 6 SCID mice and 6 C57BL/6 mice served as normal control group.10g/L (2μL) of FlouroGold was injected into the brains of the mice for the labeling of surviving retinal ganglion cells 21 days after ischemia-reperfusion.The thickness of retinal inner nuclear layer was measured by H&E staining under the fluorescent microscope 21 days after ischemic insult.The use of the animals followed the Standard of Association for Research in Vision and Ophthalmology.Results In normal control mice,the morphology of retinal ganglion cells (RGCs) and retinal structure were similar between SCID mice and C57BL/6 mice.The differences in the numbers of RGCs and retinal thickness were insignificant between the two types of mice(P＞0.05).In the experimental mice,the surviving RGCs were strikingly increased in SCID mice (91%±5%) compared with C57BL/6 mice(78%±5%)(P=0.003).The thickness of the retinal inner nuclear layer was obviously thinner in the model eyes (22.44±1.70μm) compared to model control eyes (31.06±3.75μm) in C57BL/6 mice(P=0.004),but no statistically significant difference was found between the model eyes and model control eyes in SCID mice (33.52±2.13μm vs 34.06±3.00μm) 21 days after ischemia-reperfusion injury(P＞0.05).Conclusion T and B lymphocytes deficient mice show a better tolerance to acute intraocular hypertension than the wild type C57BL/6 mice.

Correlation of glucose and lipid metabolism and inflammatory factors after a fat meal in patients with type 2 diabetes mellitus / 中华内分泌代谢杂志

so higher in diabetic patients 4 h after the meal (all P<0. 05). Positive correlation existed between serum triglycerides and white blood cell counting, neutrophils, and high-sensitivity C-reactive protein(r were between 0.268 and 0.548, all P<0.05).

Relationship between multiple risk factors and coronary artery lesions in the patients with coronary heart disease and metabolic syndrome / 第三军医大学学报

Objective To investigate the relationship between coronary artery lesions and multiple risk factors in the patients with metabolic syndrome (MS) and coronary heart disease (CHD). Methods Totally 429 patients were definitely diagnosed with CHD by coronary arteriography and their BMI, BP, FBG, TG, HDL-c as well as age, gender, smoking, TC, LDL-c, UA were recorded. All patients were divided into two groups: CHD with MS, CHD. Results BMI, BP, FBG, TG, HDL-c, TC, LDL-c and UA were significantly higher in CHD with MS group than those in CHD group (P

Relationship between apolipoprotein E polymorphism and coronary heart disease / 中国实用内科杂志

Objective To study the effect of apolipoprotein E (ApoE) polymorphism on serum lipids and the relationship between apolipoprotein E polymorphism and coronary heart disease (CHD).Methods Polymerize chain reaction (PCR) and HhaI digestion were used for the detection of apolipoprotein E genotype on 71 patients with CHD and 69 control subjects.Results The frequencies of apolipoprotein E4 allele and E3/4 genotype were obviously increased in CHD group than in control group (P<0.01,P<0.05). Conclusion The apolipoprotein E polymorphism is related to the occurrence of coronary heart disease; apolipoprotein E4 allele is one of the most important hereditary factor for the occurrence of CHD.