Tissue cages for study of experimental streptococcal infection in rabbits. I. Production of erythrogenic toxins in vivo

Tissue cages implanted subcutaneously were used to infect rabbits with erythrogenic toxin (ET) producing streptococci. The in-vivo production of ET was followed during the infection by immunoprecipitation analyses of the tissue cage fluid (TCF). ET types A and C were mainly detected during the first week of infection, but, as late as 4 weeks after the inoculation, ET was occasionally found in TCF. The nonspecific mitogenic activity of ET on human lymphocytes was also used as a biological marker to recognize ET in TCF. Mitogenic activity was detected in 90% of samples during the first week. In order to characterize the mitogenic material released by growing streptococci, TCF was electrofocused in polyacrylamide gel. The eluates of sliced gels were checked for mitogenic activity and compared with a purified ET preparation containing ET types A and C. It could be verified that ET type A was produced under in-vivo conditions by strains NY-5 and SF130, while ET type C was produced by strain T18. Differences between production of toxins in vitro and in vivo might be of significance for the understanding of the pathogenetic mechanisms in streptococcal infection.     

气管组织工程的研究策略及其展望

气管组织工程是近10年来国内外研究的热点和难点问题,取得了一些进展.但如何更好地遴选基质材料、实现种子细胞共培养、上皮化以及再血管化来构建组织工程化气管仍需要不断寻求新的研究思路和策略.本文从气管重建和理想化气管替代物的角度,回顾了近年来在组织工程气管方面的研究进展,并对未来的研究作出展望.     

Ionic conductances of cultured principal cell epithelium of renal collecting duct

The ionic conductive properties were studied of epithelia of collecting duct principal cells which had been grown in primary tissue culture from renal cortex/capsule explants. When pretreated with aldosterone (10^–6 mol/l) and bathed on either surface with isotonic HCO ₃ ^– -free Ringer's solution, the transepithelial voltage,V _te, varied between –21 and –72 mV (apical surface negative) while the transepithelial resistance,R _te, ranged from 0.4 to 1.5 kcm². By 10:1 step-changes in Na⁺ concentration the apical cell membrane was shown to have a high conductivity for sodium, inhibitable by amiloride, 10^–6 mol/l. However, contrary to observations in natural collecting duct under control conditions, amiloride never reversed the polarity ofV _te even at 10^–4 mol/l. Both the apical and the basolateral cell membranes were conductive for potassium and both conductivities were inhibitable by Ba²⁺ (5 mmol/l). 10:1 reduction of apical Cl^– concentration strongly hyperpolarizedV _te with a monophasic time course suggesting the presence of a paracellular shunt conductance for Cl^–. In addition there may be a small Cl^– conductance present in the apical cell membrane since apical application of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPAB) at 10^–7 mol/l produced a minute but significant hyperpolarization. On the other hand, 10:1 reduction of basolateral Cl^– concentration caused a biphasic change inV _te (initial depolarization, followed by repolarization) which indicates the presence of a large Cl^– conductance in the basolateral cell membrane. The latter was not inhibitable by 10^–7 mol/l NPPAB. Higher concentrations of this and of an other Cl^– channel blocker produced non-specific effects. In conclusion, our studies of a pure principal cell epithelium confirm findings described for the intact cortical collecting duct and add new information concerning chloride conductivity and related blocking agents.Dedicated to Prof. Dr. H. Sitte, Homburg, FRG, upon his 60th birthday.     

生物组织微阵列芯片自动制备仪的研制

介绍了一种新型生物组织微阵列芯片自动制备仪的研制。分析了组织微阵列制备过程中的操作任务和实现目标,进行了制备仪的结构设计和各功能模块研究开发。制备仪从结构上分为蜡块承载定位模块和三工位操作模块,控制系统的组成有操作空间精密定位子系统,组织蜡块图像识别子系统,蜡块打孔填埋作业子系统等。研制成功的制备仪样机具备了图像自动识别、精密定位、自动打孔填埋等功能,实现了生物组织微阵列芯片的自动化制备。     

Immunohistochemical study on tissue transglutaminase and copper-zinc superoxide dismutase in human myocardium: Its relevance to apoptosis detected by the nick end labelling method

The influence of free radicals on apoptosis was studied in the human heart; 45 autopsy cases were examined by the nick end labelling method (NELM) that detects DNA fragmentation. Immunostaining for copper-zinc superoxide dismutase (CuZn-SOD) and tissue transglutaminase (tTG) induced frequently during apoptosis were also studied. Positive immunoreaction for tTG was detected in mucinous degeneration of myocardial cells; these same cells were also positive for CuZn-SOD but negative for NELM. Myocardial cells showing basophilic alterations after haematoxylin and eosin staining were also positive for CuZn-SOD but negative for the other markers examined. Positive nuclear reaction by NELM was only observed in myocardial cells showing contraction band necrosis or irregularly shaped nuclei surrounding recent or long-standing infarcted foci. In these the other two markers were negative. Since mucinous degeneration lacks the distinguishing morphological features of apoptosis, immunoreactive tTG in this lesion may not imply that the cells are undergoing apoptosis. tTG can be induced in non-apoptotic conditions and may not be involved in apoptosis induced by infarction. Histological disassociation between CuZn-SOD expression and apoptosis suggests the possibility of a cytoprotective role played by endogenous CuZn-SOD against free radical generation in the human heart.     

Preparation of a pure autologous biodegradable fibrin matrix for tissue engineering

Parallel to the growing role of tissue engineering, the need for cell embedding materials, which allow cells to stabilise in a three-dimensional distribution, has increased. Although several substances have been tested, fibrin is thus far the only one that permits the clinical application of cultured tissue. To date, can cause severe immunological side effects. The objective of this study was to explore the practicability of obtaining autologous thrombin from a single patient in an adequate concentration and amount. Fibrinogen was cryoprecipitated from 200 ml of freshly-frozen plasma. Thrombin was isolated from the supernatant through ionexchange chromatography. The thrombin was first bound to Sephadex A-50 and then eluated using 2ml of a salt buffer (2.0M NaCl in 0.015M trisodiumcitrate, pH 7.0). The activity of the thrombin (51 NIH ml⁻¹ to 414 NIH ml⁻¹) reached levels comparable to those in commercially available fibrin glues (4–500 NIH ml⁻¹). The study has shown that it is possible to obtain a sufficient amount of autologous thrombin from a single donor to create a fibrin matrix of high efficiency without the risk of immunological and infectious side effects.     

Mechanical and Cellular Changes During Compaction of a Collagen-Sponge-Based Corneal Stromal Equivalent

The need for corneas suitable for transplantation, combined with the decreasing supply, has fueled interest in the development of a corneal replacement. In this study, a collagen-sponge-based stromal equivalent, consisting of human corneal fibroblasts cultured on a type I collagen sponge, was maintained in culture for up to 21 days and characterized with respect to mechanical properties and cellular behavior. The Young's modulus of the stromal equivalent varied from 95 to 370 Pa, and its permeability varied from 5.3 x 10(-8) - 4.2 x 10(-7) m4 N(-1) s(-1). The greatest changes occurred during the first few days in culture, but the mechanical properties continued to change during the entire 21 days. Cell traction stress, determined from sponge compaction and DNA count, decreased during the compaction process with the maximum traction value the initial value of 6.6 +/- 2.9 x 10(-3) Pacm3 cell(-1). Microarray data showed that the expression level of fibronectin, decorin sulfate, collagenase, and gelatinase A was upregulated at day 14 in the sponge. This suggested that the repair fibroblast phenotype was being expressed by the fibroblasts. Additional analysis suggested that a subpopulation of cells expressed the myofibroblast phenotype.     

Evaluation of antidecubitus mattresses

Pressure sores are a current problem in hospitals and care of the elderly, leading to protracted hospital stays and a high care burden. The trauma for the patients is severe, and the cost of pressure sore prevention and treatment, is considerable. Antidecubitus mattresses are used for prevention and in treatment, but they also contribute to the cost of treating pressure sores. The problem highlighted in the review is that the mattresses' effectiveness in preventing and treating pressure sores has not been sufficiently evaluated. When antidecubitus mattresses are evaluated, it is often only with regard to aspects of the interface pressure and the mattresses' ability to redistribute the pressure. The review points out the important observation that, to be able to evaluate the efficacy of the antidecubitus mattress, the mattress's effect on tissue viability needs to be studied. The parameters that ought to be considered when evaluating a support surface are: interface pressure, pressure and blood flow distribution, temperature and humidity in the skin-support surface interface. The authors propose that the effect on tissue viability of external loading can be assessed by simultaneous measurement of the interface pressure and tissue perfusion.     

肺癌组织培养液和病人血清对自身T细胞集落形成能力的影响

本文观察了10例肺癌病人围术期的肺癌组织、正常肺组织培养液和血清对自身外周血T细胞集落形成能力的影响,并以14例正常人的血清作为对照。结果显示:肺癌人病在去肿瘤负荷前T细胞集落产率为160.73±124.02/10~5,故低于正常人的397.81±133.89/10~5(P<0.001),也低于去肿瘤负荷后的(P<0.001)306.53±79.86/10~5(P<0.001)。术前病人的血清对T细胞集落的抑制率为46.97±21.42%,术后则下降至27.63±23.25%(P<0.01)。加进肺癌组织培养液时,病人的T细胞集落产率为224.83±104.05/10~5,正常肺组织培养液则为323.12±125.27/10~5(P<0.001),肺癌组织培养液和病人血清两者对T细胞集落产率的抑制性呈正相关关系(r=0.817,P<0.005)。本研究结果认为,肺癌组织能产生细胞免疫抑制物质进入血循环,导致病人T细胞集落形成能力明显下降。手术根治性切除肺癌组织,能有效地解除T细胞集落形成能力受抑制的情况。     

纳米材料在组织工程体外细胞培养中的应用进展

组织工程包括细胞和生物支架两部分.其中细胞的活性在很大程度上取决于支架材料的优劣.良好的生物支架应该能尽可能地模拟细胞在体内的内环境,从而提供细胞生长所需的微环境.纳米材料由于很好地模拟了细胞在体内的拓扑结构,从而在组织工程领域得到了越来越广泛的应用.综述了纳米材料在各种细胞体外培养中的作用,初步探讨了纳米材料对细胞促进作用的机制,并对纳米材料在肝脏组织工程中的应用进行了展望.