纤维结合素在实验性肝纤维化中动态变化研究

本实验研究了血浆纤维结合素和肝组织中纤维结合素的动态变化规律。结果显示F_n在肝中的沉积与肝纤维化的严重程度有关。在肝纤维化早期血浆F_n增高,当胶元在肝中沉积达最高峰时,血浆F_n反而下降低于正常。这提示F_n可能参予胶元在肝中的沉积并对肝纤维化的早期诊断有一定意义。     

The interaction of von Willebrand factor-A1 domain with collagen: mutation G1324S (type 2M von Willebrand disease) impairs the conformational change in A1 domain induced by collagen

BACKGROUND: It is established that the A3 domain in von Willebrand factor (VWF) contains the major collagen-binding site. However, there are conflicting reports describing the capacity of the A1 domain to interact with collagen types I and III. METHODS: In this study, we have used recombinant VWF-A1 polypeptides, as well as conformation-specific monoclonal antibodies (mAb), to analyze the A1-collagen interaction. RESULTS: The A1 domain bound to collagen with K(d) approximately 8.0 nm and this binding was blocked by the mAb 6G1, which blocks the interaction between ristocetin and VWF. In addition, collagen-bound A1 protein was able to support flow-dependent adhesion of platelets, demonstrating that the binding sites for collagen and glycoprotein (GP)Ib are different. Analysis with two conformation-specific mAb demonstrated that the structure of the A1 domain changed as a result of the binding to collagen. In contrast, the antibodies failed to detect conformational change in the G1324S mutant (type 2M von Willebrand disease). Thus, direct binding to collagen induces a change in the structural conformation within the VWF-A1 domain, and the G1324S substitution prevents this conformational change. CONCLUSION: This study has shown that the isolated A1 domain can simultaneously bind to collagen and platelet GPIb, supporting platelet adhesion under high-flow conditions. In addition, this study has used mAb to demonstrate that the binding of the isolated A1 domain or full-length VWF to collagen is accompanied by a conformational change in A1 domain.     

Detection of liver fibrosis with magnetic cross-relaxation

The utility of MRI using magnetization transfer (MT) enhanced pulse sequences to diagnose hepatic cirrhosis in a rat model was investigated. Hepatic T₁ was measured with and without MT off-resonance RF pulses in 17 treated and six control rats. The livers were evaluated histologically, and the hydroxyproline content quantitatively measured. We did not find a statistically significant linear correlation between the MR relaxation times and the degree of tissue injury. However, the MR measurements performed with MT were superior to those without differentiating the treated and control groups. Specifically, the T₁ times were 695 ±76 ms for the treated group, versus 748 ± 61 ms in the controls; P= 0.095. The T_1sat times were also lower in the treated group, with statistical significance: 367 ± 51 ms versus 421 ± 38 ms, P = 0.016. Finally, the change in the relaxation rates (the inverse of the relaxation times) with and without saturation were 1.31 ± 0.22 s^?1 (treated group) versus 1.05 ± 0.12 s^?1 (controls), which differed significantly, P= 0.001.     

Region-specific constitutive gene expression in the adult porcine meniscus.

The knee meniscus exhibits extensive spatial variations in native healing capacity, biochemical composition, and cell morphology that suggest the existence of distinct phenotypes for meniscus cells. Constitutive gene expression levels of appropriate extracellular matrix proteins may serve as useful molecular markers of cellular phenotypes; however, relatively little is known of variations in the gene expression for meniscus cells of different regions of the tissue. The objective of the present study was to evaluate constitutive differences between radial inner and outer regions in gene expression for extracellular matrix proteins relevant to the meniscus. A secondary objective was to determine if these region-specific differences in gene expression are maintained after periods of monolayer culture. The innermost regions of the meniscus were found to constitutively express higher mRNA levels for proteins highly expressed in articular cartilage, including aggrecan, type II collagen, and NOS2. In contrast, the outer meniscus was found to contain higher gene expression for proteins associated with fibrous tissues including type I collagen, and the proteases MMP2 and MMP3. Isolated inner and outer meniscus cells maintained these region-specific gene expression patterns for collagens and proteoglycans during short-term monolayer culture. The results provide new information that suggests the utility of constitutive gene expression levels as molecular markers to distinguish tissue and cells of the inner and outer meniscus.     

老化皮肤的胶原与弹性组织变化研究

目的：探讨光曝露情况及年龄因素对皮肤中弹性组织、Ⅰ/Ⅲ型胶原及基底膜Ⅳ型胶原的影响,进而探索皱纹形成的组织学原因。方法：对80例取自不同年龄志愿者的曝光部位（眶周/前额、面颊）及非曝光部位（腹部/臀部）的皮肤组织进行HE染色、Weigert染色、苦味酸天狼猩红染色及免疫组化处理,采用显微形态观察和半定量分析。结果：各部位皮肤基底膜内Ⅳ型胶原的含量无差异;随着曝光时间增加,前额/眶周皮肤中Ⅰ型胶原减少率最大,弹性变性物质增加率最大。结论：前额/眶周皮肤的胶原显著减少和弹性变性物质明显增生,是该部位皮肤皱纹早发的重要原因。     

新型神经支架材料的构建及其与骨髓基质干细胞复合的实验研究

[目的]研制出一种可用于修复周围神经缺损的组织工程支架材料,并观察体外培养的骨髓基质干细胞在支架材料中的生长情况。[方法]以I型胶原蛋白和明胶通过冷冻干燥技术制备胶原蛋白支架材料。扫描电镜观察内部结构的排列规律及走行,测量其孔径大小、孔隙率等指标。将骨髓基质干细胞复合到胶原蛋白支架材料中共培养5 d后,扫描电镜下观察其在材料内部的生长情况。[结果]构建的材料均为圆柱状,内部为孔径均匀且平行排列的微管结构,体外培养的骨髓基质干细胞成功种植在支架材料上,在材料内部生长良好。[结论]构建的支架材料具有良好的三维空间构形和生物相容性,为神经损伤的修复提供了一种新型的支架材料。     

A clinical procedure to predict the value of temporary occlusion therapy in keratoconjunctivitis sicca

PURPOSE: To evaluate the effects of dissolvable collagen punctal plugs on the symptoms, tear stability and volume in aqueous deficient dry eyes. METHODS: Sixty-two aqueous deficient dry eye patients of mixed aetiology underwent lacrimal punctal occlusion with dissolvable collagen plugs. The subjects were randomly allocated to one of two treatment groups: group I (n = 36) had their lower puncta occluded and group II (n = 26) had both their upper and lower puncta occluded. The effectiveness of this treatment was clinically assessed by (1). scoring subject symptoms and (2). measuring the tear parameters of tear thinning time (TTT) and tear meniscus height (TMH) as indicators of tear stability and volume, respectively. Following baseline measurements, patients were reviewed at time intervals of 5 and 12 days post-occlusion. A group of age- and gender-matched normals (n = 45) was recruited for comparison (group III). RESULTS: Tear volume and stability were significantly higher in group III compared with I and II at baseline. In the treated groups on both days 5 and 12: (1). symptom score reduced significantly from a median value of 7 to 3 (p = <0.001); (2). tear stability increased significantly from a median value of 3 to 5 s by day 5 (p 相似文献   

Henneguya shackletoni sp. nov. (Myxosporea, Bivalvulida, Myxobolidae) from the Falklands mullet, Eleginops maclovinus (Cuvier) (Teleostei, Eleginopidae) in the Falkland Islands

During a survey of the parasite fauna of the euryhaline notothenioid fish Eleginops maclovinus (Cuvier) caught in brackish water creeks in the Falkland Islands, small white cysts were observed in the mesenteries and on the surfaces of the visceral organs and heart. On dissection these proved to be plasmodia of a species of the myxosporean genus Henneguya. This is the first record of a member of this genus from a marine or euryhaline fish in the south-west Atlantic. A comparison of the spore of our species with other species in the genus convinced us that our species is new. This paper describes it as Henneguya shackletoni sp. nov. after the Shackleton Fund which funded the study.     

胶原凝胶复合骨胶原基质(BCM)负载关节软骨细胞的实验研究

目的 探讨胶原凝胶包埋软骨细胞接种BCM支架的三维培养对软骨细胞生长及功能的影响.方法 将胶原凝胶包埋的关节软骨细胞接种BCM支架并在体外培养,应用倒置相差显微镜和扫描电镜观察软骨细胞的粘附、生长和增殖情况,培养14d,行苏木精-伊红、甲苯胺蓝染色观察软骨组织形成情况.结果 软骨细胞在支架上粘附、生长和增殖良好,体外培养14d能形成较成熟的软骨组织.结论 胶原凝胶复合BCM支架具有良好的细胞相容性,可作为负载生长因子的载体.     

Effects of permethrin as Simulium larvicide on non-target aquatic fauna in an African river

The side-effects of permethrin (20% EC) as a Simulium larvicide on aquatic invertebrates and fish was studied under operational vector control conditions to contribute to the evaluation of the product for its possible adoption by the Onchocerciasis Control Programme in West Africa. After 15 weekly applications of the formulation at 0.045 litre per m³ of water discharge, drift samples virtually contained no Ephemeroptera. Saxicolous fauna density and proportional diversity were also affected. However, both drift and saxicolous fauna recovered to almost pretreatment levels a month after treatment was terminated. Fish showed some evidence of stress but remained in the active treated zone to make trends of catches in the area comparable with those of the control station. The treatment did not result in fish mortalities, and the condition of fish before and after the experimental period was significantly unchanged. Thus, operational use of permethrin by the Programme would not be expected to have permanent adverse effects on the non-target fauna.