脂肪间充质干细胞向髓核样细胞定向分化研究

目的探讨SD大鼠来源的髓核(nucleus pulposus,NP)细胞促使脂肪间充质干细胞(adipose tissue-derived mesenchymal stem cells,AMSCs)向NP样细胞定向分化的分子机制。方法采用酶消化法取脂肪细胞,极限稀释法纯化细胞;采用组织块培养法培养NP细胞。利用流式细胞技术,免疫荧光及RT-PCR检测对AMSCs及NP细胞进行鉴定。结果 AMSCs中Sca-1和CD44的阳性率较高,而CD45和CD11b阴性,共培养组荧光强度明显亮于单纯AMSCs组,AMSCs在NP细胞的诱导下聚焦蛋白聚糖(Aggrecan)、Ⅱ型胶原蛋白(CollagenⅡ)、Sox-9等表达水平较对照组高。结论共培养环境中髓核细胞分泌的可溶性因子TGF-1能促使AMSCs向NP样细胞定向分化。     

Regulation of human neutrophil guanylate cyclase by metal ions, free radicals and the muscarinic cholinergic receptor

We have examined the properties of soluble guanylate cyclase activity in the human neutrophil. The enzyme showed complex regulation by metal ions. A 10-fold higher activity was observed in the presence of Mn2+ than Mg2+, while Ca2+ caused an increase in activity only in the presence of Mg2+ ion. Sodium nitroprusside (SNP), azide and hydrogen peroxide were activators of the enzyme. Dithiothreitol blocked the activation by SNP, suggesting the involvement of thiol groups in the activation process. Carbachol acting through the muscarinic cholinergic receptor caused a dose-dependent activation, which was blocked by atropine. Higher concns of carbachol were required to activate guanylate cyclase than were required for the modulation of enzyme release elicited by N-formyl-L-methionyl-L-leucyl-L-phenylalanine. Nordihydroguaracetic acid inhibited carbachol stimulation of guanylate cyclase. By contrast, trifluoperazine (TFP), a calmodulin antagonist, caused a biphasic modulation of basal activity in the presence or absence of carbachol. Our results indicate that: allosteric interactions of metal ions are important to the regulation of the enzyme, the free radical nitroxide as well as hydrogen peroxide enhances enzyme activity, agonist occupancy of the muscarinic cholinergic receptor activates neutrophil guanylate cyclase probably through a mechanism involving calcium influx and the activation of the lipoxygenase pathway, and a TFP-sensitive site (possibly calmodulin) is involved in the selective regulation of basal enzyme activity.     

FT-2 antigen for distinguishing lymphocyte subpopulations in the developing thymus

The surface phenotypes of lymphoid cells in the developing embryonic thymus were characterized by using monoclonal antibodies. FT-2 antigen thus defined was predominantly expressed on thymocytes in the earlier embryonic stages in all the inbred mouse strains tested. The immunofluorescence and immunoperoxidase tests indicated that, like FT-1 antigen, the proportion of FT-2+ fetal thymocytes rapidly decreased with increase in gestation time, and these cells disappeared by day 19 of gestation. The treatment of fetal thymocytes with anti-FT-1 plus complement eliminated not only FT-1+, but also FT-2+ cells, whereas the treatment with anti-FT-2 failed to eliminate approximately 40% of FT-1+ cells, suggesting that embryonic thymocytes can be provisionally divided into at least three subpopulations, FT-1+2+, FT-1+2- and FT-1-2-.     

Anaplastic large cell Ki-1 lymphoma with bone involvement: Report of two cases

Two cases of anaplastic large cell Ki-1 lymphoma involving bone as the most prominent and initial manifestation are reported. The first patient was a 20-year-old male who had back pain and incomplete paraparesis due to vertebral involvement. The second was a 14-year-old girl, whose first clinical signs were fever of unknown origin and sternal bone pain. Radiologically, skeletal lesions were lytic and destructive. Histopathologically, the tumour cells had pleomorphic bizarre nuclei and abundant basophilic cytoplasm. Immunohistochemically, Ki-1 (CD30) reactivity was strongly positive in both cases. Tumour cells were also CD3, CD4, epithelial membrane antigen and interleukin-2 receptor positive in the first case, and CD10, HLA-DR positive in the second case. The former tumour was considered to be of T-cell lineage and the latter of lymphoid progenitor cell origin. Radiation and chemotherapy were temporarily effective. However, both patients died 14 and 7 months after diagnosis, respectively, due to systemic lymph node involvement. These observations suggest that the prognosis for Ki-1 lymphoma involving bone is poorer than indicated in previous reports.     

IL-6、IL-1及TNF对人类骨髓瘤细胞系KM_2、KM_3增殖的影响

细胞因子的异常表达对骨髓瘤细胞的恶性增殖起重要作用。本文研究了IL-6、IL-1及TNF 对人骨髓瘤细胞系增殖的影响。KM_2、KM,均能分泌IL-6,以维持自身的增殖。培养体系中加入抗IL-6抗体可抑制瘤细胞的增殖,这种抑制作用可通过加入重组IL-6而逆转.在培养体系中加入重组IL-6和TNF 均可促进KM_2、KM_3的增殖,而IL-1无此作用。培养体系中加入TNF 培养后,上清中IL-6活性增高。我们的结果提示,人骨髓瘤细胞系KM_2、KM_3存在IL-6自分泌增殖机制,而TNF 可加强这种自分泌作用。     

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.