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1.
四环三萜化合物是植物来源中药里具有多种生物活性的一类重要化合物,但研究发现四环三萜类化合物普遍口服生物利用度低,肠吸收不佳,严重影响了该类成分的开发和应用。四环三萜类化合物按照苷元不同大致可以分为达玛烷型、羊毛脂烷型、葫芦素烷型、环阿屯烷型、原帖烷型、楝烷型等几类,总结了不同结构类型的四环三萜化合物单体的肠吸收机制,探讨其肠吸收不佳的原因;综述发现肠吸收多用于研究中药单体、单味中药和中药复方配伍的有效吸收成分及其相互作用规律,并表明中药配伍对有效成分的肠道吸收具有很好的改善作用,以期为改善中药四环三萜类化合物的口服利用度、新剂型的研发设计以及临床的合理用药提供参考。  相似文献   
2.
In our paper, the magneto-optical properties of a dichroic cholesteric liquid crystal layer with large values of magneto-optical parameter g and low values of dielectric permittivity were investigated. The solutions of the dispersion equation and their peculiarities were investigated in detail. The specific properties of reflection, transmission, absorption, rotation, ellipticity spectra and also the spectra of ellipticity and azimuth of eigen polarization were investigated. The existence of a tunable linear and nonreciprocal transmission band was shown.  相似文献   
3.
Superficial amorphization and re-crystallization of silicon in <111> and <100> orientation after irradiation by femtosecond laser pulses (790 nm, 30 fs) are studied using optical imaging and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) allows fast data acquisition at multiple wavelengths and provides experimental data for calculating nanometric amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. For a radially Gaussian laser beam and at moderate peak fluences above the melting and below the ablation thresholds, laterally parabolic amorphous layer profiles with maximum thicknesses of several tens of nanometers were quantitatively attained. The accuracy of the calculations is verified experimentally by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the superficial re-solidification of silicon after local melting by femtosecond laser pulses is drawn.  相似文献   
4.
Objective:To observe the changes of symptoms,Chinese medicine(CM)syndrome,and lung inflammation absorption during convalescence in patients with coronavirus disease 2019(COVID-19)who had not totally recovered after hospital discharge and whether CM could promote the improvement process.Methods:This study was designed as a prospective cohort and nested case-control study.A total of 96 eligible patients with COVID-19 in convalescence were enrolled from Beijing Youan Hospital and Beijing Huimin Hospital and followed up from the hospital discharged day.Patients were divided into the CM(64 cases)and the control groups(32 cases)based on the treatment with or without CM and followed up at 14,28,56,and 84 days after discharge.In the CM group,patients received the 28-day CM treatment according to two types of CM syndrome.Improvements in clinical symptoms,CM syndrome,and absorption of lung inflammation were observed.Results:All the 96 patients completed the 84-day follow-up from January 21 to March 28,2020.By the 84th day of follow-up,respiratory symptoms were less than 5%.There was no significant difference in the improvement rates of symptoms,including fatigue,sputum,cough,dry throat,thirst,and upset,between the two groups(P>0.05).Totally 82 patients(85.42%)showed complete lung inflammation absorption at the 84-day follow-up.On day 14,the CM group had a significantly higher absorption rate than the control group(P<0.05)and the relative risk of absorption for CM vs.control group was 3.029(95%confidence interval:1.026-8.940).The proportions of CM syndrome types changed with time prolonging:the proportion of the pathogen residue syndrome gradually decreased,and the proportion of both qi and yin deficiency syndrome gradually increased.Conclusions:Patients with COVID-19 in convalescence had symptoms and lung inflammation after hospital discharge and recovered with time prolonging.CM could improve lung inflammation for early recovery.The types of CM syndrome can be transformed with time prolonging.  相似文献   
5.
Permanently implanted devices that deliver electrical stimulation are increasingly used to treat patients with drug-resistant epilepsy. Primary care physicians, neurologists, and epilepsy clinicians may encounter patients with a variety of implanted neuromodulation devices in the course of clinical care. Due to the rapidly changing landscape of available epilepsy-related neurostimulators, there may be uncertainty related to how these devices should be handled during imaging procedures and perioperative care. We review the safety and management of epilepsy-related implanted neurostimulators that may be encountered during imaging and surgery. We provide a summary of approved device labeling and recommendations for the practical management of these devices to help guide clinicians as they care for patients treated with bioelectronic medicine.  相似文献   
6.
目的研究腰椎间盘突出症组织不同程度自然吸收与腰椎曲度的相关性。方法回顾分析上海市宝山区仁和医院2015年1月至2019年6月CT检查确诊腰椎间盘突出症病人61例,均为保守治疗,并具有6~24个月随访复查资料。根据突出物自然吸收程度分为明显重吸收组(10例),部分重吸收组(8例),基本不变组(30例),增大组(13例)四组,配对比较每组腰椎曲线指数、腰椎前凸角变化,并进行相关分析。结果腰椎间盘突出症明显重吸收组、部分重吸收组、基本不变组、增大组的首次CT检查腰椎曲线指数、腰椎前凸角比较,差异无统计学意义(P>0.05);经治疗后随访CT腰椎曲线指数[10.65(9.23,13.31)mm 比11.69(8.31,15.25)mm 比8.63(6.75,11.00)mm 比8.06(5.00,10.05)mm]、腰椎前凸角[46.30(43.96,48.18)°比45.36(44.15,47.67)°比39.37(32.27,45.74)°比35.39(29.60,43.16)°]比较,差异有统计学意义(P<0.05)。明显吸收组、部分重吸收组随访腰椎曲线指数、腰椎前凸角较首次CT检查增大(P<0.05);增大组随访腰椎曲线指数、腰椎前凸角较首次CT检查减小(P<0.05);基本不变组腰椎曲线指数、腰椎前凸角前后配对比较差异无统计学意义(P>0.05)。腰椎间盘突出症自然吸收程度与腰椎曲线指数、腰椎前凸角变化均呈正相关(rs=0.50、0.47,P<0.05)。结论腰椎曲线指数及腰椎前凸角随着腰椎突出椎间盘自然吸收而增大,当腰椎突出椎间盘增大时腰椎曲线指数及腰椎前凸角也相应减小。腰椎间盘突出症组织自然吸收程度与腰椎曲度变化呈正相关。  相似文献   
7.
基于中医学整体观念,运用取象比类的方法,借自然界"川""海"之象进一步阐释"六经"之经与腑的双重含义,以及"肠胃为海"在气血化生、津液输布、糟粕传化、扶正培本方面的内涵.指出"六经"与"肠胃"在生理上彼此依存、病理上相互影响.在现代肠道研究中,肠道消化吸收营养物质、排泄代谢废物,体现了肠胃为"气血生化之海""津液输布之海""糟粕传化之海".肠道菌群促进肠黏膜免疫系统的发育并参与调节机体免疫,体现了肠胃为"扶正培本之海".肠神经系统与内分泌系统通过脑-肠轴的双向调控,如同六经与肠胃之间的海川循环,彼此依存、生生不息.通过探析"六经为川,肠胃为海"在肠道各功能网络中的内涵,揭示象思维在中西医整合医学发展中的重要作用,为挖掘经典及科研创新开辟思路.  相似文献   
8.
刘晓丹  杨筱倩  唐三  丁煌  黄小平  邓常清 《中草药》2019,50(7):1649-1656
目的探讨冰片是否具有促进黄芪甲苷(AST IV)和三七总皂苷(PNS)配伍时主要有效成分透过大脑中动脉栓塞(MCAO)再灌注模型大鼠血脑屏障的作用。方法大鼠随机分为假手术组、模型组、冰片组、AST IV组、PNS组、AST IV+PNS组、冰片+AST IV+PNS组,制备MCAO再灌注大鼠模型,以液相色谱-质谱联用法(LC-MS/MS)测定大鼠患侧与健侧大脑皮层、小脑中AST IV和PNS有效成分(人参皂苷Rg1、Rb1和三七皂苷R1)的含量。结果 AST IV无论是单用还是与PNS、冰片配伍,其口服后主要分布在大脑皮层,尤其是患侧大脑皮层。冰片+AST IV+PNS能使患侧与健侧大脑皮层中AST IV含量显著增加。PNS单用,其有效成分人参皂苷Rg1、Rb1和三七皂苷R1主要分布在患侧小脑。冰片+AST IV+PNS能使患侧大脑皮层中人参皂苷Rb1含量显著增加,使健侧和患侧大脑皮层中人参皂苷Rg1含量增加,使大脑皮层尤其是患侧大脑皮层及小脑中三七皂苷R1含量增加。结论大鼠脑缺血再灌注后,AST IV与PNS的有效成分人参皂苷Rb1、Rg1及三七皂苷R1在大脑皮层和小脑均有一定的分布。AST IV单用时,AST IV主要分布在大脑皮层;PNS单用时,人参皂苷Rb1、Rg1及三七皂苷R1主要分布在小脑。冰片与AST IV、PNS合用后,能促进AST IV及人参皂苷Rb1、Rg1及三七皂苷R1向大脑皮层富集,尤其是向缺血再灌注侧大脑皮层富集;而且能不同程度地促进AST IV,人参皂苷Rb1、Rg1及三七皂苷R1在大脑皮层的吸收,尤其是在患侧大脑皮层的吸收。  相似文献   
9.
目的:制备同时适合于黄芩素、黄连素及大蒜素3种中药成分的自乳化载体体系,并考察这3种自乳化制剂的体外透皮吸收效果。方法:采用饱和溶解度法、伪三元相图法、正交试验筛选最佳的空白处方组成及基质用量。以Franz扩散池和离体大鼠皮肤进行体外透皮吸收试验,采用HPLC分别测定3种自乳化制剂中黄芩素、黄连素及大蒜素的累积透皮渗透量,并分别与黄芩素散剂、黄连素散剂及大蒜素散剂进行比较。结果:最佳处方为油酸乙酯-聚氧乙烯氢化蓖麻油40-聚乙二醇400载体体系,所形成的自乳化制剂粒径适宜,其微观形态呈较规整的球形。透皮吸收10 h,黄芩素、黄连素及大蒜素3种自乳化制剂的药物透皮速率分别为6.898 6,7.600 4,190.040μg·cm~(-2)·h~(-1),累积透皮渗透量分别为71.38,85.54,1 795.16μg·cm~(-2)。结论:成功制备了不同种类中药成分均能使用的自乳化载体体系,且该自乳化制剂的体外透皮吸收效果良好,可为后续中药复方自乳化制剂的制备及其透皮给药吸收研究提供实验依据。  相似文献   
10.
GL‐V9, a derivative of wogonin, has potent anti‐cancer activity. The absorption and metabolism of this compound have not been investigated systematically. This study aims to illustrate the pharmacokinetic characters of GL‐V9 by exploring its metabolic status under different administration routes. To further clarify the absorption mechanism of GL‐V9, an in situ single‐pass perfusion model and a Caco‐2 cell monolayer model were used. Meanwhile, a microsomal incubation system was used to evaluate the enzyme kinetic parameters. In vivo, the obtained gastrointestinal availability (Fa × Fg) was 21.28 ± 5.38%. The unmetabolized fraction in the gut wall (Fgut wall) was 98.59 ± 9.74%, while the hepatic bioavailability (Fh) was 29.11 ± 5.22%. These results indicated that poor absorption and extensive metabolism may contribute greatly to the low bioavailability of GL‐V9. The effective permeability (Peff) in the duodenum and jejunum was 1.34 ± 0.50 × 10?4 and 0.90 ± 0.27 × 10?4 cm/s, respectively. The high permeability of GL‐V9 indicated that other unknown factors (such as metabolism) may account for its systemic exposure problem. Studies in rat liver microsomal (RLMs) confirmed this hypothesis, and the Clint, CYP450s and UGT of GL‐V9 was 0.20 ml/min/mg protein. In conclusion, these results suggest that GL‐V9 possesses higher permeability than wogonin and the metabolism of GL‐V9 is related to its disposition in rat intestine and liver.  相似文献   
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