知识模式转换在医学科技创新中的作用

医学科技创新是医院赖以生存与发展的动力,医学科技创新的过程也是医学知识模式不断转换的过程,本文从知识模式转换的视角,探讨知识管理对医学科技创新的意义与作用     

Magnetic and electrical stimulation of undulating nerve fibres: a simulation study

Mathematical models of myelinated nerve fibres are highly stylized abstractions of real nerve fibres. For example, nerve fibres are usually assumed to be perfectly straight. Such idealizations can cause discrepancies between theoretical predictions and experimental results. One well-known discrepancy is that the currently used models predict (contradictory to experimental findings) that an activation of nerve fibres is not possible with a pure transverse electric field. This situation occurs when a magnetic coil is placed symmetrically above a straight nerve fibre for magnetic nerve stimulation, or when an anode and a cathode are placed equidistantly on a line perpendicular to the fibre in the case of electrical stimulation. It is shown that this discrepancy does not occur if the physiological undulation of peripheral nerve fibres is included in the models. Even for small undulation amplitudes (e.g. 0.02 mm), it is possible to activate the fibre in these positions. For physiological undulations, as found in the literature, and favourable (off-centre) positions, the typical reduction of the thresholds is in a range between one and five, compared with perfectly straight fibres.     

踏跳瞬间足后部骨骼的三维有限元分析

目的建立足部三维有限元模型,对足后部骨骼在踏跳中的应力分布进行分析。方法应用CT扫描和CAD/CAM软件处理,建立足后部骨骼三维模型。通过对背跃式跳高踏跳的足底压力测量和逆向肌肉力量计算,确定载荷约束条件,并进行有限元计算。结果获得了踏跳瞬间,跟骨、距骨、舟骨等易损伤部位的生物力学响应和应力分布,发现跟骨后距关节,距骨背面均为应力集中处。结论本研究建立的模型可用于足后部骨骼生物力学研究,为踏跳中的运动损伤力学机理提供数据。     

高山红景天多糖对小鼠抗柯萨奇B5病毒感染能力的研究

对感染柯萨奇Ｂ５病毒（ＣＶＢ）小鼠模型研究结果表明，高山红景天多糖对发病小鼠心肌功能改善和免疫功能提高均具有明显的促进作用。增强了小鼠抗ＣＶＢ５感染的能力，并对由ＣＢＶ感染性疾病也有一定的防治作用。     

肝癌索拉非尼敏感性预测模型的构建及临床意义

目的：基于生物信息学方法构建并验证肝细胞癌(以下简称肝癌)对索拉非尼敏感性相关基因的预后风险模型,探究该模型对肝癌患者预后和对索拉非尼敏感性的预测能力。 方法：本研究对GSE109211数据集、TCGA-LIHC队列、ICGC-LIRI队列进行差异基因分析,通过交集筛选出肝癌索拉非尼敏感性相关基因。利用单因素Cox分析和LASSO回归构建预后风险模型并进行验证。通过GDSC数据库分析索拉非尼的IC50值并探索其与风险评分的关系。 结果：筛选出365个与索拉非尼敏感性相关的基因,富集分析显示存在与药物代谢相关的信号通路。单因素Cox回归分析出221个与预后相关的基因,通过LASSO回归构建了一个包含7个关键基因的预后风险模型,与低风险组相比,高风险组具有较短的生存时间。多因素Cox回归分析显示风险评分是独立的预后因素。通过对比高、低风险组患者的索拉非尼IC50值,发现高风险组的索拉非尼IC50值较低,提示高风险组对索拉非尼的治疗可能更敏感。 结论：基于索拉非尼敏感性相关基因构建的预后风险模型对肝癌患者预后具有良好的预测价值,并为评估肝癌患者的索拉非尼敏感性提供理论依据。     

Generalized pharmacokinetic modeling for drugs with nonlinear binding: I. Theoretical framework

The following integrodifferential equation is proposed as the basis for a generalized treatment of pharmacokinetic systems in which nonlinear binding occurs $$\phi '(c_u )c'_u = - q(c_u ) + g*c_u + f$$ where c_u≡unbound plasma drug concentration, f≡drug input rate,'indicates the derivative of a function, and * indicates the convolution operation: (g* c_u)(t)=∫ ₀ ^t g(t?u)c_udu.Possible physical interpretations of the functions q, g and f are: q (c_u)≡ rate at which drug leaves the sampling compartment, g * c_u ≡ rate at which drug returns to the sampling compartment from the peripheral system (tissues that are kinetically distinct from the sampling compartment), and φ(c_u) ≡ amount of drug in the sampling compartment. The approach assumes that drug binding is sufficiently rapid that it may be treated as an equilibrium process. It may be applied to systems in which nonlinear binding occurs within the sampling compartment, i.e., in the systemic circulation or in tissues to which drug is rapidly distributed. The proposed relationship is a generalization of most existing models for drugs with nonlinear binding. It can serve as a general theoretical framework for such models or as the basis for “model-independent” methods for analyzing the pharmacokinetics of drugs with nonlinear binding. Computer programs for the numerical solution of the integrodifferential equation are presented. Methods for pharmacokinetic system characterization, prediction and bioavailability are presented and demonstrated.     

Effect of ipratropium bromide on airway and pulmonary muscarinic receptors in a rat model of chronic obstructive pulmonary disease

Objective　To observe the level of muscarinic receptors in airway and lung tissues, and the effect of inhaled ipratropium bromide on these receptors in a rat model of chronic obstructive pulmonary disease (COPD). Methods　This model was developed by exposure of rats to 250 ppm SO2 gas, 5?h/d, 5d/wk, for a period of 7 wk. The COPD rats inhaled 0.025% aerosolized iratropium bromide for 20 min, 2 times daily, in an airtight chamber. Muscarinic receptors in airway and lung tissues of normal rats, ipratropium bromide-treated COPD rats and the recovering COPD rats were measured by the radio-ligand binding assay. Results　Airway/lung pathology and pulmonary function tests showed that chronic SO2 exposure caused pathophysiologic changes similar to those observed in human COPD. The density (0.038±0.011, pmol/mg protein) and affinity (Kd, 23±11 pmol/L) of muscarinic receptors in airway and lung tissues of COPD rats were not changed compared with those of normal control rats (0.030±0.008 and 29±19, respectively, P>0.05). Densities of the muscarinic receptors were not changed after inhalation of ipratropium bromide for 5 days, but increased significantly after inhalation for 30 days, as compared with those of the untreated COPD rats. The muscarinic receptors returned the normal levels at day 6 after cessation of ipratropium bromide treatment. There were no differences among different groups of rats in equilibrium dissociation constants (Kd). Conclusion　A rat model of COPD with pathophysiologic changes similar to the human counterpart was developed using chronic SO2 exposure. There was no significant change in the number and function of muscarinic receptors in airway and lung tissues of the COPD rats, but upregulation of the muscarinic receptors was observed after long-term inhalation of ipratropium bromide.     

The acceptance of SARS-CoV-2 rapid antigen self-testing: A cross-sectional study in China

Compared with the nucleic acid amplification test (NATT), the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid antigen self-testing (RAST) has advantages in speed and convenience. However, little is known about people's acceptance and influencing factors for SARS-CoV-2 RAST. A cross-sectional study was conducted from April 21 to 30, 2022 in China. The χ² test and multivariate logistic regressions were used to identify the influencing factors. The structural equation model was used to test the extended protective motivation theory (PMT) model hypotheses. Among the total of 5107 participants, 62.5% were willing to accept the SARS-CoV-2 RAST. There were significant differences in acceptance among different residences (p < 0.001), educational level (p < 0.001), occupation (p < 0.001), monthly income (p < 0.001), travel frequency (p < 0.05), and feelings about NATT (p < 0.001). Response efficacy (β = 0.05; p = 0.025) and self-efficacy (β = 0.84; p < 0.001) had a positive effect, while response cost showed a negative effect (β = −0.07; p < 0.001). The public's major concerns about SARS-CoV-2 RAST are its reliability, testing method, price, and authority. Overall, a moderate intention to use SARS-CoV-2 RAST was found among the Chinese population. The extended PMT can be used for the prediction of intention to accept the RAST. We need to take measures to increase people's acceptance of SARS-CoV-2 RAST.     

头高位倾斜时心血管反应的仿真

仿真头高位倾斜时心血管系统的反应,进一步研究有关立位应激的生理机制。方法以仿真下体负压时心血管反应的模型为基础,在血液重新分配子模中引入了重力致血液重新转移的环节,在压力反射控制子模型中考虑了心水平与颈动脉压力感受器间的流体静压差。