稀土元素的生物安全性探讨

采用微核检测、单细胞凝胶电泳、同工酶等技术研究了稀土元素遗传毒理效应的有关结果。大量试验表明,稀土元素断裂DNA的能力,因而在一定浓度范围内,稀土元素确有致突变性。稀土元素在土壤中可专性吸附、不可降解,在动植物和人体皆有累积效应,因此稀土元素的生物安全性值得深入探讨。     

纳米二氧化钛的生物学效应

纳米二氧化钛在国内外的研究与应用已经非常广泛．在涂料、颜料、陶瓷、化妆等方面的应用与人体有密切的接触。由于物质在纳米尺度会产生很多宏观尺度所不具有的特殊效应,在宏观尺度被证实无毒无害的二氧化钛,当被制备到纳米尺度时,对人体的作用是否仍然安全,这个问题已引起一部分科学研究工作者的关注。该文简要介绍与纳米二氧化钛生物效应相关的一些特性;纳米二氧化钛毒性,包括纳米二氧化钛的渗透性、体内急性毒性、细胞毒性,以及对DNA的损伤等。目前国内外对纳米二氧化钛的毒性机制研究尚处在一个猜测性的阶段,其中对蛋白质、氨基酸等生物大分子作用的研究仍是一个空白。     

纳米细菌与生物矿化关系研究现状

纳米细菌（Nanobacteria NB）是芬兰科学家KAJANDER等在培养哺乳动物细胞时发现在无污染的情况下,仍有部分细胞生长繁殖不佳,发生空泡样变性、溶解或凋亡。针对此种现象他们对已知所有微生物进行了检测,结果都为阴性。于是对这些细胞进行透射电镜观察,结果在细胞内发现了一种很小的原核微生物,在上世纪90年代由KAJANDER命名这种生物为Nanobacteria并申请了专利。     

超声的生物效应

鉴于超声已在临床医学中取得了日益普遍的应用。本文综述了超声的生物效应及其在分子,细胞,组织,器官,系统和整体水平上对动物和人体的影响,并提供了动物试验结果。     

纳米与生物

Nano 是希腊文中的单词,有“小矮人”的意思。在英文中,Nano 作为一个词头,放在任何单位前面都表示“十亿分之一”,而它与长度单位“米”相连接,就变成了如今众所周知的纳米,即十亿分之一米。     

微波生物效应研究的现状及应用

着重介绍了微波对微生物、黄曲霉素、人及动物的生物效应,以及微波在浸取和医学上的应用。     

细胞工厂和生物纳米机器

细胞是维持生命活动的基本单元,也是最繁忙的工厂,其内含有无数的纳米机器,它们无时不刻地作功,而且高度精准、有序协调,以维持正常新陈代谢。本文从纳米生物学角度探讨在细胞中所发生的事件,总结概述生物纳米机器类型,细胞工厂的组织结构及分工,生物纳米机器的主要特点,以及研究生物纳米机器的目的。     

荧光纳米生物传感器研究进展

荧光纳米生物传感器检测物质具有灵敏度高、响应迅速、抗干扰性强、无需参比电极等特点而被广泛地运用于生物传感技术领域。本文综述了荧光纳米生物传感器种类和特点,介绍了国内外近期在荧光纳米生物传感器及在生物检测方面的一些研究成果及进展,并作了分析比较。着重讨论了纳米粒子荧光生物传感器和光纤纳米荧光生物传感器的特性及其在生物分析中的应用。     

The biological activities of interleukin-1

Interleukin-1 (IL-1) refers to a hormone-like polypeptide that mediates a broad spectrum of activities in host defence as well as a variety of disease processes. Originally described as a substance produced by activated macrophages, IL-1 is now recognized as a polypeptide produced by many other cell types. Two distinct genes have been identified that code for two structurally related forms of the molecule, termed IL-1 alpha and beta. IL-1 is the primary mediator of the acute phase response and is responsible for many of the changes associated with the onset of infection. It is involved in the immune response to antigenic challenge. IL-1 induces fever and has profound endocrinologic, neurologic, metabolic and hematologic effects. Both forms of IL-1 bind to a common receptor that has been identified on a variety of cell types including lymphocytes, hepatocytes, endothelial cells and fibroblasts. Many of the activities of IL-1 are mediated by the induction of other cytokines like IL-2, IL-6, interferons, tumor necrosis factor, and colony-stimulating factors. In animals IL-1 protects against the effects of radiation, it enhances natural resistance of infection, and it stimulates bone marrow recovery after myelosuppression. These studies suggest that IL-1 may be used as a therapeutic agent.     

The complement system and its biological activities

The complement system is a non specific humoral defence mechanism which can be triggered by various effectors : immune-complexes, extrinsic proteases, bacterial cell-wall polysaccharides, viral membranes. Different peptides or multimolecular complexes are formed by a cascade of proteolytic cleavages; they take an active part in the inflammatory response and may contribute to different pathological manifestations.     

The biological activities of mannans and related complex carbohydrates

Complex polymers containing mannose (mannans) possess significant biological activity when administered to mammals. When given orally, they inhibit cholesterol absorption and induce hypocholesterolemia. If administered by other routes, they bind to mannose-binding proteins and induce macrophage activation and interleukin-1 release, inhibit viral replication, stimulate bone marrow activity, promote wound healing and inhibit tumor growth. This range of activities makes the mannans, potentially important biological-response modifiers and therapeutic agents.     

Nanoscale sensors for assuring the safety of food products

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The relationship of biological and immunological activities of factor VIII

Factor VIII is an essential blood clotting factor which consists of two protein moieties, each with distinct biological functions and antigenic determinants. The immunological markers were originally seen as indicators of the biological activities; however this view has been increasingly challenged. We have investigated the biological and immunological properties of Factor VIII to clarify these relationships. Plasma stored at room temperature for 21 days lost biological activity, but retained immunological activity: The procoagulant activity was reduced to 35% and the ristocetin cofactor activity to 75.4% of their original levels; but the reactivities of both procoagulant antigen and Factor VIII related antigen were maintained. A dissociation of activities was also demonstrated in serum, in which the procoagulant activity was 10% and the procoagulant antigen 72% of corresponding plasma values. These results indicate that the antigenic reactivities are not appropriate markers for Factor VIII biological activity.     

The synthesis and biological activities of some 12-Aza-prostaglandin analogues

12-Aza-prostaglandin (PG) analogues containing the pyrrolidine-2,4-dione ring system have been synthesized from ,2-disubstituted glycine esters via cyclisation of their -ethoxycarbonylacetyl derivatives. 5-(6-Carboxyhexyl)-1-octylpyrrolidine-2,4-dione (5) had little or no PG-like activity on superfused intestinal or vascular smooth muscle preparations but it selectively antagonised smooth muscle responses to PGE₂, PGE₁, PGF_2α and PGA₂in vitro. At a concentration of 10⁻⁵ g/ml it reduced responses of the rat stomach strip to PGE₂ by over 80% but did not affect responses of this tissue to acetylcholine, 5-hydroxytryptamine (5-HT) or bradykinin. Polyphloretin phosphate (PPP), the known PG antagonist, had a similar effect at the same concentration (10⁻⁵ g/ml).5-(6-Carboxyhexyl)-1-(3-hydroxyoctyl)pyrrolidine-2,4-dione (12) had the same profile of activity on superfused smooth muscle preparations as PGE₂ or PGA₂. On intravenous injection into anaesthetised rats it caused dose-dependent falls in arterial blood pressure with associated tachycardias, which is typical of the response to PGE₂. The smooth muscle activity of (12) was not reduced by passage through isolated perfused guinea-pig lungs nor was its potency as a vasodepressor increased when given intra-arterially to rats. These results suggest that, unlike PGE₂, this analogue is not removed by the pulmonary circulation.     

Analysis and biological activities of anthocyanins

Anthocyanins are naturally occurring compounds that impart color to fruits, vegetables, and plants. They are probably the most important group of visible plant pigments besides chlorophyll. Apart from imparting color to plants, anthocyanins also have an array of health-promoting benefits, as they can protect against a variety of oxidants through a various number of mechanisms. However, anthocyanins have received less attention than other flavonoids, despite this. This article reviews their biological functions and pre-clinical studies, as well as the most recent analytical techniques concerning anthocyanin isolation and identification.     

The biological activities of fish peptides and methods of their isolation

Fish, like other aquatic organisms, are a potential source of structurally diverse bioactive compounds. Studies of the pharmacological effects of fish peptides have revealed their antihypertensive, immunomodulatory, antioxidant, antitumor, and antimicrobial activities. Analysis of the literature data confirms that fish can be used not only for nutritional purposes, but also as a source of unique peptides with a broad spectrum of biological activities. Further investigations will allow the inclusion of fish peptides as acting agents in modern medicinal drugs.