GFAP,FVIII/RAg,Laminin, and fibronectin in gliosarcomas: An immunohistochemical study

Summary GFAP, Factor VIII/RAg, laminin, and fibronectin were immunohistochemically investigated in 15 glioblastomas and 15 gliosarcomas. GFAP was found variably positive in the glial areas. F VIII/RAg characterizes the endothelial cells and in gliosarcomas suggests the origin of the sarcomatous component from the endothelial proliferations. Laminin separates the two components and characterizes the inner and the outer basement membranes in the vessels. It is multiplied and thickened in endothelial proliferations, while it is often fragmented in the larger vessel wall proliferations. Our observations confirm that gliosarcoma represents the last stage of a process which starts with the endothelial hyperplasia of glioblastoma.Partially supported by CNR, Special Project Center, Grant no. 82.00410.96     

视网膜色素上皮细胞吞噬纤维连接蛋白时细胞内信号传导通路的研究

目的 探讨视网膜色素上皮（retinal pigment epithelium PRE)细胞对纤维连接蛋白（fibronectin,FN）的吞及相关细胞内信号传导通路的作用。方法 以FN包被的聚苯乙烯微球（微球）作为吞噬标记物, 建立人胎儿RPE细胞吞噬模型。所研究的细胞内信号传导通路包括蛋白激酶C（protein kinase C,PKC)通路、酪氨酸激酶（tyrosine kinase,TK）通路和磷酯酰肌醇3－激酶（phosphatidylinositol 3-kinase,PI3-K)通路,分别使用这3种信号通路的抑制剂预处理RPE细胞,37℃吞噬3h,流式细胞仪定量检测吞噬指数。结果 与对照组比较,RPE细胞对FN包被微球有明显吞噬作用（P＜0．05）。PKC抑制剂PMA（phorbol 12-myristate 13-acetate,100nmol/L)或Calphostin C(400nmol/L)非特异性地增加了PRE细胞对FN包被或未包被微球的吞噬指数（P＜0．01）;TK和PI3K的抑制剂Genistein(100μg/ml）与Wortmannin(5μmol/L）分别降低了FN包被微球的吞噬指数（P＜0．001）,但对对照组无影响。联合使用不同抑剂Genistein或Wortmannin可对抗PMA对FN吞噬的增强作用,但二者联合使用则具有相累加的抑制吞噬作用。结论 PRE细胞对FN的吞噬受细胞内PKC、TK和PI3－K信号传导通路的调节,此结论将为进一步研究治疗增殖性玻璃体视网膜病变的药物提供理论依据。     

Modulatory effects of fibronectin on in vitro lymphocyte responses

Summary In rat studies, fibronectin (Fn), a ubiquitous glycoprotein, is a T-cell mitogen and stimulates the production of interleukin 1 by peritoneal exudate macrophages. In contrast, Fn has no mitogenic activity for human lymphocytes and does not stimulate interleukin 1 release by human peripheral blood mononuclear cells. Fn increases in vitro peripheral blood mononuclear cell phytohemagglutinin responses in normals and patients with active, but not inactive, rheumatoid arthritis. Fn may alter local immunoregulation and play an active role in the rheumatoid synovial lesion.     

黄芪通过c-met调控TGF-β1诱导的肾小管上皮细胞转分化

AB 目的：探讨黄芪对TGF-β1诱导的肾小管上皮细胞转分化及细胞外基质分泌的作用及机制。方法：体外培养正常大鼠肾小管上皮细胞（NRK52E）,应用倒置相差显微镜观察NRK52E细胞形态学变化;免疫组织化学染色法及实时荧光定量PCR法检测α-平滑肌肌动蛋白（α-SMA）,肝细胞生长因子HGF受体（c-met）的表达;ELISA法定量检测细胞上清液中胶原Ⅰ（Col-Ⅰ）,胶原Ⅲ（Col-Ⅲ）和纤维黏连蛋白（FN）的水平。结果：TGF-β1可诱导肾小管上皮细胞肌成纤维细胞转分化（TEMT）,TGF-β1诱导组细胞肥大、拉长,呈长梭形,α-SMA表达明显增强,Col-Ⅰ、Col-Ⅲ和FN分泌增加（P〈0.05）。加入不同浓度黄芪后,细胞形态接近正常肾小管上皮细胞形态,α-SMA表达、Col-Ⅰ、Col-Ⅲ和FN分泌均较TGF-β1诱导组明显抑制（P〈0.05）,c-met表达较TGF-β1诱导组增加（P〈0.05）且呈剂量依赖性。结论：TGF-β1可以诱导肾小管上皮细胞肌成纤维细胞转分化,增加细胞外基质成分Col-Ⅰ、Col-Ⅲ和FN的分泌;黄芪能够抑制TGF-β1诱导的NRK52E细胞转分化以及细胞外基质的分泌;黄芪抑制细胞转分化的机制可能与其增强c-met的表达有关。     

The maturation-dependent change in fibronectin receptor density of mouse dorsal root ganglion neurons

The maturation-dependent change in fibronectin receptor density of mouse dorsal root ganglion neurons were investigated by an immuno-cytofluorometric method. The receptor density showed a drastic decrease around birth and a smaller change after birth.     

Is chemotaxis a factor in the migration of precardiac mesoderm in the chick?

Summary The chick heart is formed from bilateral patches of presumptive cardiac mesoderm cells which migrate over the endoderm and fuse in the midline. We have tested the possibility that this migration is controlled, at least in part, by a chemotactic substance exuded by the anterior end of the endoderm. We have used chick/quail combinations to follow naturally marked cells during the course of their migration. Chimaeric embryos were formed by fusing together parts of chick and quail embryos of stage 5–6. Each embryo possessed two pairs of precardiac regions, the quail pair lying immediately anterior to that of the chick. These chimaeras were then explanted in embryo culture. In the event of chemotaxis, cells from the posterior end of the quail precardiac mesoderm might be expected to invade the chick area. Samples of explants and chimaeras were examined at intervals from 2 to 24 h, but in no case were cells found to have changed their direction of migration as a result of the proximity of anterior endoderm. It is concluded that this work does not provide evidence for a chemotactic attraction by the anterior end of the endoderm. Supported by the following grants: NIH HD 21048, HD 06819, and AHA 880696 (JWL); the British Heart Foundation, and Action Research (R.B.); and an SERC postgraduate studentship (HSE).     

Differential regulation of glycosaminoglycan,fibronectin, and collagenase production in cultured human dermal fibroblasts by interferon-alpha,-beta,and-gamma

Summary In order to determine whether interferons (IFNs) play a universal role in terminating the fibrotic response by inhibiting other fibroblast functions in addition to growth and collagen production, we investigated the effect of human recombinant (hu-r) IFN-alpha,-beta, and-gamma on the glycosaminoglycan, fibronectin, and collagenase production of cultured human dermal fibroblasts. Our results show that shortterm (48 h) treatment of confluent fibroblast cultures with hu-r-IFN-alpha₂ and hu-r-IFN-beta-ser₁₇ causes a concentration (1 to 1×10⁵ U/ml)-dependent inhibition of glycosaminoglycan production, has no effect on fibronectin production, and markedly increases collagenase production. In contrast, hu-r-IFN-gamma not only causes a concentration-dependent increase in collagenase production but also increases both glycosaminoglycan and fibronectin production. These results demonstrate that IFNs differently regulate fibroblast functions rather than universally inhibit all functions, and show that IFN-alpha and-beta exhibit a broader antifibrotic spectrum that IFN-gamma.     

Fibronectin in synovial fluid and tissue in rheumatoid arthritis

Fibronectin is a glycoprotein found in body fluids, loose connective tissue matrix and in basement membranes. Fibronectin in rheumatoid arthritis synovial fluid was immunologically indistinguishable from the plasma form, as shown by double-diffusion analysis. Fibronectin isolated from rheumatoid synovial fluid by affinity chromatography on gelatin--Sepharose had a polypeptide pattern similar to that of plasma fibronectin in SDS--polyacrylamide gel electrophoresis. In fifty-one patients with rheumatoid arthritis and related diseases fibronectin concentrations is synovial fluid were 445 +/- 103 micrograms/ml (mean +/- SD) and within normal range, 335 +/- 52 micrograms/ml, in plasma. Immunofluorescence staining showed a prominent increase of fibronectin in the proliferating synovial connective tissue in rheumatoid arthritis as compared to normal synovial membrane. The results suggest an increased local production of fibronectin in rheumatoid synovial tissue.     

Plasma fibronectin and complement following infusion of colloidal solutions after spinal anaesthesia

A randomized study of 30 patients undergoing uncomplicated surgery under spinal anaesthesia was conducted to assess the influence of colloids on the kinetics of plasma fibronectin and complement. Both are opsonins of the reticuloendothelial system; moreover fibronectin is concerned with host resistance against septic complications following trauma and surgery. The patients were assigned to receive either Ringer's lactate (Group 1), gelatin (Group 2) or dextran 40 (Group 3). Blood samples were withdrawn before colloids or Ringer's infusion and during the 4 postoperative days. There was a reduction in plasma fibronectin throughout the study in groups 1 and 3, but an increase in group 2 by 24h. The adhesion of plasma fibronectin to gelatin was maximal 1h after infusion (44%) and remained significant up to day 2 in group 2. There was no relationship in groups 1 and 3. C3 and C4 components of complement exhibited a low value in the early post-operative period, due to hemodilution. This study shows an in vivo fibronectin-gelatin interaction, and suggests that gelatin infusion inhibits the increased shift of plasma fibronectin at the site of tissue injury after surgery.The study was supported by a grant from the Cernep Synthelabo laboratory