Adhesion in the biologic environment

There are good reasons to believe that adhesion of particulate matter in all wet, salty, biochemically active circumstances follows a common pattern, and that such adhesion can be effectively controlled by adjusting the surface properties - especially surface energy--of the substrate involved. One of the most compelling proofs of, at least, the bioengineering utility of surface energy modification to maximize or minimize biological adhesion is the successful, now long-term, implantation of total artificial hearts. These pumps, and the related intra-aortic balloons and left ventricular assist devices, do not accumulate blood clots or thrombotic masses during their contact with natural blood. Since surfaces contacting blood have received most careful scrutiny for more than a decade, the instruction gained from examining the usual and unusual sequelae of blood cell adhesion to nonphysiologic surfaces has been most valuable in revealing the general features of biological adhesion in other, less well-studied, circumstances. The initial events of blood contact with foreign solid surfaces are briefly reviewed, and the impressive similarities of these events to sequences in oceanic fouling of heat exchangers, cell culture experiments and dental plaque formation are highlighted. A unifying concept, based on control of the surface free energy through an empirical correlate called the "critical surface tension," is presented as an explanation for the common features of biological adhesion in all of Nature's domains.     

浅谈医疗设备静电的防护

现代电子产品科技含量及设备集成度越来越高 ,大多数设备都会受到静电的危害。医疗设备是集光、机、电、微电脑于一体的高技术产品 ,直接用于对人体疾病的诊断、治疗以及各种生理参数、状态的测试 ,由于静电对这些高精度的医疗设备具有一定的危害 ,为了保证设备在医疗工作中正常工作 ,因此 ,我们有必要做好医疗设备的静电防护工作。     

氧气加压舱的静电防护

叙述静电对氧气加压舱的危害及防护措施     

表皮葡萄球菌黏附机制的研究

目的了解我院表皮葡萄球菌ica操纵子、表达产物PIA的阳性率及其与黏附的关系。方法采用PCR对ica操纵子中icaA基因进行扩增并进行琼脂糖电泳检测;采用刚果红琼脂检测基因产物PIA;采用输液器管壁黏附表皮葡萄球菌量评价其对输液器管壁的黏附能力。结果表皮葡萄球菌ica操纵子中icaA基因检出率为51.5%,PIA检出率为50.0%;PIA阳性、阴性两组菌落计数均值分别为4.94×105CFU/ml、1.40×105CFU/ml,差异有统计学意义(P<0.05)。结论PCR检测表皮葡萄球菌icaA方法简便易行,能可靠地反映其PIA的表达情况;PIA阳性、阴性表皮葡萄球菌的黏附能力差异有统计学意义。     

改革谨防浮躁

笔者近日浏览新闻,见某电视台一则消息赫然拟题《保证公立医院零差价医院患者都满意》,顿感不安。不安不为别的,只是因为公立医院实施“零差价”,暂时还是局部地区刚刚推行的改革,很多地方的措施至今还待字闺中,赶在这时就给出“医院患者都满意”的结论,难免为时尚早。     

Adhesion molecules in melanoma--more than just superglue?

Malignant melanoma is increasing in incidence, and, though early lesions are readily treatable, systemic therapy for metastatic disease remains disappointing. Integrins are a family of cell-surface molecules that mediate adhesion between the cell and the extracellular matrix. One member of the integrin family, the alpha v beta 3 integrin, is associated with progression of melanomas, in that the most malignant cells express the highest levels of alpha v beta 3. Like many members of the integrin family, alpha v beta 3 recognizes the sequence Arg-Gly-Asp (RGD) in its ligands, and other molecules that contain this sequence will complete with the natural ligands (such as vitronectin) for binding. There is growing evidence that integrins function as receptors for signal transduction, and that integrin-mediated signalling can affect cell behaviour and even cell survival. Under certain circumstances, loss of integrin-mediated signalling will induce apoptosis, or programmed cell death, and we have demonstrated that melanoma cells treated with a cyclic peptide with high affinity for the alpha v beta 3 integrin will undergo apoptosis within three days. This mechanism might be exploited therapeutically.     

医疗仪器使用中的静电放电的危害及防护

本文介绍了静电的产生、危害及医疗仪器的静电的防护。     

Precipitation of trace elements in parenteral nutrition mixtures

Trace elements are an essential additive to parenteral nutrition (PN) mixtures. Previous studies have indicated that certain trace elements, in particular copper and iron, may interact with complete PN mixtures leading to precipitate formation. The causes of these incompatibilities have not been fully elucidated. The purpose of this study was to determine factors responsible for common trace element incompatibilities, using X-ray energy dispersive spectroscopy to examine the elemental content of precipitates isolated from stored PN mixtures with added trace elements. Results indicated that copper sulphide precipitated most rapidly in PN mixtures containing Vamin 9 and in mixtures stored in multilayered bags. Copper sulphide precipitation was delayed in PN mixtures containing Vamin 14 and was not observed in PN mixtures stored in EVA bags. Iron phosphate precipitates were observed in Synthamin-containing PN mixtures after storage, but this was prevented in mixtures containing vitamins stored in multilayered bags.     

Electrostatic effects in asbestos sampling. I: Experimental measurements

Electrostatic charge can cause errors during sampling of airborne asbestos fibers and other particles. The change in particle trajectories caused by charge effects during sampling can result in nonuniform deposits on the collecting filter surface and net loss of sample. The degree of these electrostatic effects depends on particle charge, sampler charge, sampler conductivity, and sampling flow rate and direction. The purpose of this research was to evaluate the dependence of sampling efficiency and sample uniformity on these variables. Humidity has been postulated as a primary determinant of particle charge during aerosol generation. Measurements of particle charge and concentration were made as a function of relative humidity with chrysotile fibers generated from a fluidized bed. A strong increase in charge and a decrease in concentration of fibers was noted as the relative humidity was decreased below 15%. The effects of conductive versus nonconductive samplers and sampling flow rate were measured as a function of particle and sampler charge levels. Nonconductive samplers can carry a large and variable charge distribution on their surfaces. This can result in a biased and highly variable particle deposit on the filter when sampling charged particles. Conductive cowls spread any acquired charge over the entire surface and produce a more symmetrical and less biased charged particle deposit. Increasing the sampling flow rate will improve sampling efficiency and decrease deposit variability because the charged particle has less time to interact with the field produced by the sampler. These results suggest that sampling problems caused by electrostatic charge interactions are most likely to occur under low humidity conditions of dust generation, that sampling should be done at as high a flow rate as possible to reduce these effects, and that analysts should select fields toward the center of the filter to minimize bias and variability.     

Adhesion of Solid Particles to Solid Surfaces

Social habits and customs are related to different disease patterns. Snuff inserted in the nares has been shown to be associated with the incidence of antral carcinoma in the Bantu. Carcinoma of the maxillary antrum constitutes 45.5% of all the respiratory tract cancers in the Bantu. A pilot study was conducted to examine the trace metal content in samples of Swazi snuff by atomic absorption spectrometry. The metals analyzed were zinc, chromium, copper, lead, nickel, and cadmium. Samples of soot from Swazi huts were also analyzed for the same metals. The Swazi snuff showed high concentrations of nickel, chromium, and zinc. Since nickel and chromium in some forms are known carcinogens, the association between carcinoma of the maxillary antrum and snuff may be prevented if the source of trace metal contamination is eliminated.     

两种细胞粘附检测方法的比较

目的　细胞与细胞之间及细胞与基质之间的粘附作用是细胞间信号传递及多种细胞生物活动的基础 ,细胞粘附作用的检测是细胞生物学研究中重要的实验方法之一。本文对采用51Cr释放实验及3 H -TdR掺入法检测细胞粘附的方法进行了比较。方法　将铺底细胞以 0 5× 10 5 /孔的密度于 96孔培养板中铺底培养 2 4h ,待检细胞以51Cr或3 H -TdR标记 ,以 1× 10 5/孔的浓度加入96孔培养板中 ,作用 4h后轻柔洗去未粘附细胞。按相应检测系统检测51Cr及3 H -TdR标记的粘附细胞的放射强度 ,比较其灵敏度和稳定性。结果　51Cr释放实验及3 H -TdR掺入法均具有较好的敏感性和稳定性。相比较 ,3 H -TdR掺入法的敏感性和稳定性更好。这两种方法均能准确地检测细胞间的粘附现象 ,并反映其相对强弱。结论　采用同位素标记的方法 ,其敏感性和稳定性均较好 ,且干扰因素少 ,所获结果稳定可靠 ,3 H -TdR掺入法的敏感性和稳定性较51Cr释放法好。     

静电吸附式空气净化器在急诊外科换药室的应用

目的 探讨有效空气消毒方法,以便提高急诊外科换药过程中的空气质量.方法 设试验组和对照组,试验组为静电吸附组对诊室空气进行消毒干预,对照组不采取任何干预措施,分别采急诊外科换药室,换药前、中、后3个不同时点空气样本,进行细菌菌落计数.结果 试验组在换药前、中、后所测细菌总数均低于对照组,两组间细菌总数比较Z值分别为13.58、41.14、30.94;两组间细菌总数差异有统计学意义(P＜0.01).结论 试验组采用静电吸附空气消毒方法,能有效降低急诊外科换药室内空气细菌数量.     

医疗设备的静电防护

This paper describes the harms of the static electricity to medical devices ＆ equipments and its protection.     

The Role of Intercellular Adhesion Molecule-1 (ICAM-1), Vascular Cell Adhesion Molecule-1 (VCAM-1), and Regulated on Activation,Normal T-Cell Expressed and Secreted (RANTES) in the Relationship between Air Pollution and Asthma among Children

To evaluate the role of adhesion molecules and chemokines in the relationship between air pollution and asthma, the authors determined the following in 230 children who lived in 4 communities in Japan that had different levels of air pollution: serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1); soluble vascular cell adhesion molecule-1 (sVCAM-1); regulated on activation, normal T-cell expressed and secreted (RANTES); and total immunoglobulin E (IgE). Children with asthma or who exhibited wheezing (n = 115) and nonasthmatic children (n = 115) were studied. Serum concentrations of sICAM-1, sVCAM-1, and RANTES were increased significantly in asthmatic children, compared with nonasthmatic children. Nonasthmatic children with serum IgE levels that were greater than or equal to 250 IU/ml had significantly lower concentrations of sICAM-1 and sVCAM-1 than the other children. The geometric means of sICAM-1 increased as air pollution increased. The results of this study suggest that adhesion molecules or chemokines are associated with asthma and that ICAM-1 may play an important role in the relationship between air pollution and the occurrence of asthma.