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溴乙酰胺对钉螺超微结构的影响 总被引:10,自引:0,他引:10
本文应用电子显微镜技术观察了正常钉螺及溴乙酰胺作用后的钉螺头足部软体组织及肝脏组织的超微结构。头足部软体组织有上皮层、上皮下层及肌层。上皮层有三种细胞:无纤毛上皮细胞、纤毛上皮细胞及含有大量粘性分泌颗粒的腺体细胞。上皮层细胞内含有丰富的线粒体、内质网及张力细丝。基底膜将上皮细胞与上皮下层分开,上皮下层有含色素颗粒的细胞。肌层为梭形细胞,核居中央,无横纹。溴乙酰胺作用24小时后,钉螺头足部的上皮细胞与肝脏腺管细胞肿胀,核增大;染色质凝集,线粒体肿胀、嵴断裂呈空泡状,粗面内质网变粗呈短管状,排列混乱,或呈同心圆指纹状排列。这些病变与生化代谢结合进行了讨论。 相似文献
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... Despite the need for physicians to be knowledgeable about and open to advances in genetic technology, little is known about the level of preparedness of primary care physicians to offer new genetic tests. Evidence suggests that several barriers exist to physicians adopting genetic tests. These include lack of knowledge, inability to interpret probabilistic information, low tolerance for uncertainty, negative attitudes about their responsibility for genetic counseling and testing, lack of confidence in their clinical skills, and unfamiliarity with ethical issues raised by testing. This paper will explore some of these barriers in further depth, discuss the ethical impact of physician unpreparedness on both patient care and the diffusion of genetic tests, and describe a study that is currently underway to investigate some of these issues. 相似文献
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In this work, we have calculated the optimal surface area per amphiphile molecule using a two-dimensional gas of electric dipoles interacting with hard The optimal surface area can be evaluated according to a formula (in the two-body approximation) or as a root of an equation (in the three-body approximation). If the equation has more than one positive root, which is greater than the hard core area, then a polydisperse dimensional distribution of supramolecular aggregates is possible. 相似文献
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In this paper we present a model for the ion exchange effects in protein adsorption. The model is applied to chromatography of lysozyme on strong cation exchanger ‘mono S’. The experimental and general thermodynamic aspects have been discussed in Part 1, the preceding paper. The main modelling assumptions are (i) the charge regulation is confined to the small layer of contact between adsorbed protein and exchanger surface, (ii) the contact layer as a whole is electroneutral and (iii) the number of protein acid/base groups and exchanger surface acid groups which participate in the ion exchange is proportional to the area of the contact layer. The model is fitted to the experimental data by adjustment of only two or three parameters. The experimental co-adsorption numbers are very well reproduced. A few conspicuous features emerge: (i) the number of protein acid/base groups and exchanger surface acid groups in the contact layer varies with the medium conditions, such that the number is higher when the interaction between protein and exchanger surface is stronger. (ii) There is indirect evidence for structural alterations in the upper layers of the exchanger surface: the adsorbed protein is probably partly ‘buried’ in the surface. 相似文献
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The induced dipole moment of a purple membrane parallel to the membrane surface was analysed based on the two-dimensional fluctuation theory of counterions. The observed polarizability previously measured by electric dichroism and its dependence on the membrane size were derived from theory for the case where the interaction between counterions was screened. The screening effect of salts on the induced dipole moment was estimated from the theory on diffuse double layers. 相似文献