天然产物抗氧化活性成分研究进展

天然产物抗氧化剂在自然界有广泛的分布,研究表明多糖、黄酮、多酚、生物碱、皂苷、维生素等天然产物均能有效清除自由基以保护机体健康。随着人们回归自然思潮的兴起及安全意识的提高,天然抗氧化剂因其高效、低毒更是倍受关注。从天然产物中寻找新的清除体内自由基的抗氧化剂已成为现代医药、保健行业发展的必然趋势。综述了天然产物抗氧化活性成分的研究进展,以期为天然产物抗氧化活性的研究和发展提供参考。     

Effect of 99 GHz continuous millimeter wave electro-magnetic radiation on E. coli viability and metabolic activity

Purpose:?To investigate time exposure dependence of continuous millimeter wave (CW) 99?GHz radiation on Escherichia coli bacterial cell viability and metabolic activity.

Materials and methods:?Suspensions of E. coli bacterial cells with an optical density of OD_660nm?=?0.1 were used for viability tests and OD_660nm?=?1.0 for metabolic activity tests. These suspensions were exposed to 99?GHz CW electromagnetic radiation, generated by a Backward Wave Oscillator (BWO) tube base instrument with a horn antenna at the BWO exit, to obtain an almost ideal Gaussian beam. Calculations of the Gaussian beam show that a power of 0.2?mW/cm² was obtained at the bacterial plane.

Results:?The experimental results show that 1 hour of exposure to 99?GHz CW electromagnetic radiation had no effect on E. coli viability and colony characterisation. In 19?h of radiation, the number of colonies forming units was half order of magnitude higher than the sham-exposed and the control. However, 19?h of exposure did not affect the E. coli metabolic activity.

Conclusions:?Exposure of E. coli to millimeter wave (MW) CW 99?GHz radiation for a short period did not affect the viability of E. coli bacterial cells. However, exposure for 19?h caused a slight proliferation but did not influence the metabolic activities of about 90 biochemical reactions that were examined. Hence, we assume that the slight proliferation (half order of magnitude) after 19?h of exposure dose not have a biological meaning.     

Insights into capacity-constrained optimal transport

A variant of the classical optimal transportation problem is the following: among all joint measures with fixed marginals and that are dominated by a given density, find the optimal one. Existence and uniqueness of solutions to this variant were established by Korman and McCann. In the present article, we expose an unexpected symmetry leading to explicit examples in two and more dimensions. These are inspired in part by simulations in one dimension that display singularities and topology and in part by two further developments: the identification of all extreme points in the feasible set and an approach to uniqueness based on constructing feasible perturbations.     

Measurement of brain natriuretic peptide in plasma samples and cardiac tissue extracts by means of an immunoradiometric assay method

Background: The mechanisms of oxygen‐induced effects on blood vessels (vasoconstriction in hyperoxaemia and vasodilatation during hypoxaemia) are uncertain. Many investigators have suggested that the vasoconstriction seen during hyperoxia/hyperoxaemia is mediated through the endothelium as a result of either increased release or activity of vasoconstrictors (oxygen radicals, endothelin, norepinephrine, angiotensin II, or serotonin (5‐HT)), or reduced activity of vasodilators (prostaglandin E₂ and nitric oxide). Serotonin has been assumed to have a central role. Methods: Eight healthy volunteers were exposed to F_iO₂ of 1.0 for 20?min and serum concentrations of serotonin and activated platelets were measured (indicated by concentrations of β‐thromboglobulin (β‐TG)). Results. During hyperoxaemia in humans, serum concentrations of serotonin and β‐TG remained unchanged. Conclusion: If serotonin is involved in oxygen‐induced vasoconstriction, the mechanism is more likely to be either a potentiating effect of serotonin on other vasoconstrictors or increased activity of serotonin on its receptor.     

Effects of oral contraceptive combinations containing levonorgestrel or desogestrel on serum proteins and androgen binding

The effects of the oral contraceptive combinations 0.125 mg Org 2969 (desogestrel) (13-ethyl-11-methylene-18, 19-dinor-17α-pregn-4-en-20-yn-17—01) + 0.05 mg ethinyloestradiol (EE) and 0.125 mg levonorgestrel + 0.05 mg EE on serum sex-hormone-binding globulin (SHBG), ceruloplasmin, transcortin and ratio free testosterone over total testosterone (percentage free testosterone) and ratio free 5α-dihydrotestosterone over total 5α-dihydrotestosterone (percentage free 5α-dihydrotestosterone) were compared in healthy female volunteers.

Treatment was randomly distributed over the volunteers; 11 women received Org 2969 + EE and 11 women received levonorgestrel + EE. These combinations induced similar increases in transcortin levels (115 and 140%) and ceruloplasmin levels (115 and 123 %) after 3 months of treatment. However, the combination Org 2969 + EE induced a substantial increase (213%) in SHBG capacity after 3 months of treatment, whereas a smaller increase (80%) was observed with levonorgestrel + EE. A return to pretreatment values was observed 2 months after termination of treatment for all parameters. The difference in the effects of both preparations on SHBG was statistically significant and can be best explained by a difference in the androgenicity of the progestogens. A good correlation was observed between SHBG capacity and the reciprocal value of the percentage free testosterone and the reciprocal value of the percentage free 5α-dihydro-testosterone. These results confirm that SHBG is the major regulator of the biologically active free androgen fraction in women before, during and after combined oral contraceptive treatment.     

淀粉样变治疗学研究的最新进展

既往10—15年中系统性淀粉样变新治疗的发展取得了实质性进展。这些进展改善了患者的转归，但亦带来新的临床问题。例如，由于淀粉样轻链（K或入）（AL）淀粉样变对自体造血干细胞移植的作用不太肯定，为此正在开发广泛途径的治疗研究和提供最佳支持治疗。现认为淀粉样前体和成熟原纤维促使淀粉样变相关的器官病变，显示完全清除AL淀粉样变患者促淀粉样（amyloidogenic）轻链生成的重要性，同时治疗前后需作淀粉样前体蛋白和器官病变标记的监测。     

Effect of some free radical scavengers on reperfusion induced arrhythmias in the isolated rat heart

The possible role of oxygen free radicals in the development of reperfusion arrhythmias was investigated using a 10-min period of coronary ligation followed by reperfusion in the isolated rat heart. Superoxide dismutase (5 to 20 u/ml) glutathione (10(-5) to 10(3)M) and ascorbic acid (10(-4) to 5 X 10(-4) M) when given before coronary ligation attenuated the development of reperfusion arrhythmias. Mannitol (2 X 10(-2)M) and catalase (100 and 300 u/ml) did not have any significant effect on reperfusion arrhythmias when given alone but they did potentiate the antiarrhythmic effect of superoxide dismutase. Glutathione, and a combination of superoxide dismutase, catalase and mannitol also reduced the incidence of reperfusion induced ventricular fibrillation when given just before reperfusion. By perfusing hearts with ferricytochrome C it was possible to show an increased reduction of ferricytochrome C during the first minute of reperfusion which could be prevented by the addition of superoxide dismutase. These results provide evidence that oxygen free radicals are produced and may be important in the genesis of reperfusion induced arrhythmias in the isolated rat heart.     

延迟复苏对烫伤大鼠心肝肾氧自由基生成的影响及维生素E和维生素C治疗效果评价

采用３６只肠内含５种细菌悉生的大鼠，分成伤前对照组（Ⅰ组）、早期复苏组（Ⅱ组）、延迟复苏组（Ⅲ组）和治疗组（Ⅳ组），观察了伤后８ｈ和１ｄ心、肝、肾氧自由基（ＯＦＲ）相对量（ＥＳＲ技术）及丙二醛（ＭＤＡ）含量变化。结果发现，Ⅱ、Ⅲ组大鼠心、肝、肾ＯＦＲ相对含量均增高，Ⅲ组升高更明显，各时间点较Ⅱ组均有显著差异（Ｐ＜０．０１），尤以肾脏升高最明显。Ⅳ组各脏器ＯＦＲ相对含量低于Ⅲ组（Ｐ＜０．０１）。各脏器ＭＤＡ含量与ＯＦＲ相对含量变化规律基本一致。该结果表明，延迟复苏增加烧伤后早期脏器ＯＦＲ生成，导致脂质过氧化反应加重，ＯＦＲ对肾脏的影响可能重于其它脏器。维生素Ｅ、维生素Ｃ联合治疗可有效清除脏器中ＯＦＲ，可用于延迟复苏后脏器功能保护。     

腹主动脉阻断导致内脏缺血再灌注损伤的研究

目的观察腹主动脉阻断所引起的肝、肾、小肠等内脏缺血再灌注损伤的改变。方法建立小猪腹主动脉阻断１小时的模型,检测在不同再灌注时点组织及血液中丙二醛（ＭＤＡ）和超氧化物歧化酶（ＳＯＤ）的变化,同时检测肝肾功能和动脉血气分析,观察动物术后的生存情况。结果与缺血前比较,大多数再灌注时点血、组织中ＭＤＡ明显升高,而ＳＯＤ明显降低（Ｐ＜０．０５）。在再灌注２小时,血中谷丙转氨酶（ＡＬＴ）、尿素氮（ＢＵＮ）、肌酐（ＣＲＥ）较缺血前明显升高（Ｐ＜０．０１）,代谢性酸中毒也极为明显。多数动物术后能够存活,但均出现下肢截瘫。结论腹主动脉阻断１小时能引起明显的内脏缺血再灌注损伤改变,多数内脏经处理后其损伤能够得到代偿恢复,而脊髓损伤恢复困难。     

复温对大鼠移植肝脏抗氧自由基损伤的研究

目的　探讨复温对抗氧自由基损伤,保护移植肝脏的作用。方法　建立下腔静脉内置管法大鼠自体原位肝移植模型。在再灌流前对移植肝脏用不同温度进行复温,动态观察肝组织中脂质过氧化物（ＬＰＯ） 含量和超氧化物歧化酶（ＳＯＤ） 活性的变化,并同步观察肝细胞光镜和透视电镜下的形态学变化。结果　再灌流后与复温后比较ＬＰＯ有显著升高,ＳＯＤ 有明显下降（ Ｐ＜０ ．０１） 。用３６ ℃复温组与其他各复温组比较可明显减少ＬＰＯ的升高和ＳＯＤ 的下降（Ｐ＜ ０．０５）;同步病理也证明用３６ ℃复温可明显减轻肝细胞的损伤。结论　复温可间接抑制氧自由基的产生,减轻再灌流损伤,能够达到保护肝细胞的作用。