Pattern of secretion in thymic epithelial cells: Ultrastructural studies of the effect of blockage at various levels

Summary The observation of secretory phenomena in mouse thymic epithelial cells is disappointing since no real secretion image is found. An adequate technique for such a study is to block the secretion pathway and to observe by electron microscopy cells accumulating secretory products. For this purpose, we used three means of blocking secretion: Firstly, since the thymic epithelial cell is regulated by a feedback phenomenon, secretion was blocked by antibodies against thymulin, one of the hormones secreted by these cells. Secondly, colchicine was used to modify the intracellular transport of the secretory product. In both of these types of experiments, electron microscopy showed a great increase in the number of clear vacuoles and their granular contents in epithelial cells. In a third series of experiments, we used monensin at a concentration that blocks the intracellular transport of secretory proteins at the various levels of the Golgi apparatus. In this series, only an increased number of vacuoles was observed, but they appeared devoid of all granular content. It can be concluded that in the thymic epithelial cell, a discrete system of secretion directs the passage of the product, originating in the cisternae of the endoplasmic reticulum, into clear vacuoles, the terminal element of the cellular secretory apparatus.     

A feline large granular lymphoma and its derived cell line

Summary A lymphoma cell line (MCC) was derived from an abdominal mass from a 13-yr-old castrated male cat. The cells resemble natural killer precursor cells, have membrane-bound granules, and are positive for chloroacetate esterase, α-naphthyl butyrate esterase, and tartrate-resistant acid phosphatase activities. The MCC cells are negative for rearranged feline T-cell receptor genes, negative for feline T-cytotoxic antigen, Ia, and surface μ, τ, and lambda chains and do not form E-rosettes. The MCC cell line is negative for the feline leukemia virus (FeLV); e.g., negative for exogenous FeLV (exU3) sequences, negative for cytoplasmic and surface FeLV major core protein of 27 000 daltons (p27) by indirect, immunofluorescence assay, negative for helper FeLV by clone 81 assay, and negative for release of soluble FeLV p27 by enzyme-linked immunosorbent assay. Electron microscopy reveals budding type C retrovirus particles and MCC cells react with anti-RD-114 (anti-endogenous feline retrovirus) reference serum. After in vitro infection, MCC replicate FeLV readily, but replication is noncytopathic. This project has been funded, at least in part, with funds from the U.S. Department of Health and Human services under grants AI 25722, DK41939, and CA 35742 and contract AI-62525.     

New sesquiterpenes from Pleocarphus revolutus

Six new sesquiterpenes of the guaiane and isopatchoulenone types have been isolated from the Chilean plant Pleocarphus revolutus. Of these, the compound hydroxy-isopatchoulenone and related esters showed cytotoxicity towards TLX5 mouse mammary lymphoma cells.     

Immunoflow cytometry compared with PCR for the identification of clonality in FNAs of T-cell-rich B-cell lymphomas

OBJECTIVE: The study aimed to compare the utility of immunoflow cytometry (IFC) with two IgH polymerase chain reaction (PCR) methods for the identification of clonality in fine needle aspirations (FNAs) from T-cell-rich B-cell lymphomas (TCRBCLs). METHODS: Ten cases of TCRBCLs were identified in which IFC had been performed according to our previously described method. Seven of these were cases in which the original diagnosis had been made by FNA cytology with IFC and cell block immunohistochemistry (IHC). The remaining three cases only had biopsies with histology, IFC and IHC. Formalin-fixed paraffin-embedded FNA cell block or histology tissue from these specimens had also been submitted for IgH PCR clonality studies using primers FR2a/VLJH and primers FR3a/VLJH. The results were reviewed and compared. RESULTS: All 10 case demonstrated B-cell clonality for at least one of the primer sets on PCR, but none showed light chain restriction on IFC. All TCRBCLs were positive for CD20 and CD79a but negative for CD10 and BCl-2. They were also consistently negative for CD22, CD23, CD5, CD43, ALK-1, cyclin D1 and CD30. CONCLUSIONS: If IgH PCR clonality assays had a turnaround time of 1 or 2 days, there might be a strong case for these studies supporting or even replacing IFC, in the FNA diagnosis of lymphoid lesions.     

Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis

1. Download : Download high-res image (223KB)
2. Download : Download full-size image

     

Brentuximab vedotin

Brentuximab vedotin (SGN-35; Adcetris®) is an anti-CD30 antibody conjugated via a protease-cleavable linker to the potent anti-microtubule agent monomethyl auristatin E (MMAE). Following binding to CD30, brentuximab vedotin is rapidly internalized and transported to lysosomes where MMAE is released and binds to tubulin, leading to cell cycle arrest and apoptosis. Several trials have shown durable antitumor activity with a manageable safety profile in patients with relapsed/refractory Hodgkin lymphoma, systemic anaplastic large cell lymphoma, or primary cutaneous CD30-positive lymphoproliferative disorders. Peripheral sensory neuropathy is a significant adverse event associated with brentuximab vedotin administration. Neuropathy symptoms are cumulative and dose-related. Multiple ongoing trials are currently evaluating brentuximab vedotin alone or in combination with other agents in relapsed/refractory patients, as well as patients with newly diagnosed disease.     

2-12烷基-6-甲氧基环己基-2,5-二烯-1,4-二酮(DMDD)抗弥漫大B淋巴瘤的作用及机制*

目的:探讨2-12烷基-6-甲氧基环己基-2,5-二烯-1,4-二酮(DMDD)抗弥漫大B淋巴瘤(DLBCL)的作用及分子机制。方法:动物实验取4周龄BALB/C小鼠,分5组,20只/组,腹股沟注射DLBCL细胞株OCI-LY19细胞1 × 10⁷ cells/ml 每只0.1 ml,两天后分别灌胃0、1、5、25、125 mg/kg剂量的DMDD,1次/2天,给药的第18日,杀10只小鼠,取瘤组织称重,记录剩余小鼠的生存期。细胞实验取OCI-LY19细胞加入96孔培养板,每孔100 μl 1×10⁵ cells/ml,分别加入100 μl DMDD使其终浓度分别为0、1、5、25和125 μmol/L,作用0、24、48和72 h,设三复孔,MTS法检测细胞增殖活性;根据细胞增殖实验结果,选择0 μmol/L、5 μmol/L和25 μmol/L的DMDD作为后续用药浓度作用OCI-LY19细胞24 h,流式细胞仪分析凋亡率,hoechst染色观察细胞核型,JC-1染色观察线粒体膜电位,LDH释放实验评估药物细胞毒性,qPCR、Western blot分析基因转录和表达水平。结果:动物实验表明:与0 mg/kg用药组比,1～125 mg/kg DMDD能抑制小鼠瘤组织生长并延长其生存期(P＜0.01)。细胞实验表明:DMDD用药组OCI-LY19细胞增殖活性明显降低、凋亡水平显著增加(P＜0.01),细胞核出现碎裂、凝集和凋亡小体及线粒体膜电位下降,LDH释放率显著增加(P＜0.01),细胞内caspase-3和bax基因的转录表达和IκBα的磷酸化水平显著上调,bcl-2、bcl-xL、jak2和stat3基因的转录和蛋白表达水平明显受抑(P＜0.01)。结论:DMDD通过抑制JAK2/STAT3和NF-κB信号通路中JAK2、STAT3和p-IκBα的表达,下调BCL-2/BAX、活化Caspase-3,最终激活OCI-LY19细胞线粒体凋亡的内源性通路而促进了DLBCL细胞凋亡,抑制了OCI-LY19细胞增殖,具有抗DLBCL的作用。