The role of fibronectin in tumor implantation at surgical sites

Fibronectins are a family of glycoproteins with modular functional domains. They mediate cell-cell and cell-matrix interactions which are important in embryogenesis, wound healing, metastasis and other processes. We present data on the influence of fibronectin on wound implantation of a murine mammary carcinoma line, TA3Ha. Fibronectin used in these studies was derived from bovine plasma, human serum, human foreskin fibroblasts, and mouse embryo cultures. TA3Ha cells rarely form tumors in the liver of syngeneic mice when injected intravenously but after hepatic wedge resection, 45% (107/240) of the mice develop tumors in the hepatic wound. Wound implantation is markedly reduced when the cells are pre-exposed to 200 µg/ml bovine plasma fibronectin (13%, P = 0.007), human serum fibronectin (0%, P = 0.02), human cellular fibronectin (0%, P = 0.02), or mouse cellular fibronectin (0%, P = 0.04). Lung colonization is also reduced by these fibronectins. These effects are not due to a cytotoxic action of fibronectin, since intraperitoneally injected fibronectin-treated cells form ascites tumor as effectively as do control untreated cells. Local application of a solution containing 0.25 mg/ml mouse cellular fibronectin to the hepatic wound reduces the frequency of tumor implantation from 45% to 5% (1/21, P = 0.001). No tumor implantation inhibition is seen when only suspending medium or albumin in suspending medium is used. The mechanism by which topical application of fibronectin reduces hepatic wound implantation of tumor cells is unclear, but this finding raises an exciting possibility of preventing local recurrence of cancer.     

Injuries to the profunda femoris artery and its branches

Six cases of uncommon profunda femoris artery injury are analyzed. One half of the cases were not treated surgically at the time of injury and resulted in chronic arteriovenous fistulas. Even after operative correction, residual symptoms persisted in two of these three cases. The generous use of arteriography is recommended in cases of proximal thigh penetrating injuries to avoid this problem. Either repair or ligation of the injured vessel yielded the same good results. The postoperative hospital stay was short in all instances, ranging from four to eight days, and there were no deaths.     

Antigen presentation is a function of all B cell subpopulations separated on the basis of size

Purified splenic B cells from nonimmune mice were separated by counterflow centrifugal elutriation into 6 subpopulations containing cells of discrete sizes ranging from 119 to 200 μm³. B cells of each subpopulation were competent to process and present a native globular protein antigen, cytochrome c, to a cytochrome c-specific T cell hybrid. In all cases, the B cells' antigen-presenting function was radiation sensitive and did not require T cells or T cell products, since B cells fixed with paraformaldehyde effectively presented a carboxyl-terminal peptide fragment of cytochrome c containing the T cell determinant. Furthermore, the antigen-presenting function of B cells of each subpopulation was augmented by treatment with submitogenic doses of the F(ab')₂ fragment of rabbit anti-mouse Ig antibodies, in that 10-30-fold fewer B cells were required and higher maximal T cell responses were achieved, indicating that B cells of all sizes are capable of being regulated in their antigen presentation function through their surface Ig. In addition, B cells of each subpopulation responded to soluble factors present in the supernatants of activated T cells as evidenced by an increase in volume and by the uptake of [³H]thymidine. These results indicate that B cells, regardless of size, are able to participate in at least two essential phases of T cell-dependent antibody responses, initiating the interaction by processing and presenting antigen to helper T cells and responding to soluble helper factors secreted by activated T cells.     

Roberts铜盐法测定蔗汁葡聚糖含量的热效应——淀粉对受热蔗汁葡聚糖测定的影响

作者从研究中发现:用Roberts铜盐法测定蔗汁样本葡聚糖含量时,所得结果与蔗汁的受热有关,受热蔗汁的测定值高于真实值,作者将这种现象暂称为Roberts铜盐法测定蔗汁样本葡聚糖含量的热效应。研究表明:蔗汁中的淀粉是引起热效应的重要因素。本文最后提出了一种由淀粉引起的热效应的可行校正方法。     

实验性顺铂诱导急性肾功能衰竭动物模型的研究

1目的　建立顺铂 (cisplatin,CP)诱导的急性肾功能衰竭 (acute renal failure,ARF )大鼠模型 ,探讨 ARF的发病机制。2方法　 SD大鼠静脉一次性注射 CP 6 mg/ kg,动态观察大鼠血清肌酐 (Scr)、尿素氮 (BUN)变化以及肾组织形态学改变。 3结果　对照组不同时间 Scr、BUN差异不明显 (P>0 .0 5 ) ,肾组织形态学正常。模型组 Scr、BUN第 4d较第 1d明显升高 (P<0 .0 5 )。肾组织形态学显示 ,肾脏髓质外侧带大部分肾小管坏死 ,细胞核固缩、溶解、消失 ,管腔扩张 ,有坏死脱落碎屑。 4结论　 CP诱导的大鼠 ARF模型为一较为理想的 ARF模型     

Cr Migration Potential and Species Properties in the Soil Profile from a Chromate Production Site in the Groundwater Depression Cone Area

The relationship between the migration process and speciation distribution of Cr is important for the risk assessment in the underground environment. In this work, soil columns were collected from the chromate production site, with a 40-year operation, in the groundwater depression cone area of North China plain. The relationship between chromium pollution features and the geochemical properties of soil was established, and the migration risk of Cr(VI) was assessed based on the Nemerow composite index and Hydrus-1D model. The maximum total Cr concentration in the chromium slag dumping site reached 907 mg/kg, and that in the chromate production workshop was more than 200 mg/kg across the depth. The migration of Cr might be accelerated in the soil with abundant Mn (236–1461 mg/kg) but scarce organic matters (<?0.45%). The Hydrus simulation indicated that Cr(VI) would reach a cumulative flux of 300–729 mg/cm² after 50 years.

     

Characterisation of the IgE-binding immunodominant epitopes on Ara h1

Peanut allergy is one of the most severe food allergies due to its persistency and life-threatening character. Serum IgE from patients with documented peanut hypersensitivity reactions and synthetic peptides were used to screen the linear IgE-binding epitopes on the major peanut allergen, Ara h 1. Five major epitopes that bound peanut-specific serum IgE from more than 60% of patients tested were identified. Mutational analysis of the immunodominant epitope showed that single amino acid changes had dramatic effects on IgE-binding characteristics. Mapping and characterisation of the IgE-binding epitopes on Ara h1 could be used in future immunotherapeutic approaches for peanut allergy disease.