Renewal of the membrane complex of Schistosoma mansoni is closely associated with lipid metabolism

Metabolic pathways leading to lipid biosynthesis in four different developmental stages of Schistosoma mansoni were explored and quantified by incubation in the presence of labeled precursors in a chemically defined medium. At the schistosomulum stage and in male, female, or paired worms, glycerol and oleate incorporation into neutral lipids, mainly in the form of triacylglycerols, was greater than into phospholipids, whereas in 11-and 15-day-old worms, synthesis mainly led to phospholipids. Incorporation into phospholipids was recovered largely in phosphatidylcholine, and distribution into other phospholipids depended on the developmental stage. Incorporation of choline and ethanolamine into their respective phospholipids represented up to 15% of the parasitic phospholipid content. The formation of phosphatidylcholine by phosphatidylethanolamine methylation occurred mainly in the immature parasitic stages. Inositol incorporation was also measurable, whereas [14C]serine incorporation was low or undetectable. Addition of 1-palmitoyl-2-[14C]oleyl phosphatidylcholine revealed a very high uptake of this phospholipid by the immature stages but further metabolism was not detectable. In contrast, adult S. mansoni were completely unable to take up or absorb this exogenous phospholipid. The most striking aspect of this study was the relatively high metabolic activity in 11-day-old worms and the lower but sustained activity on day 15 and at the schistosomulum stage. By comparison, biosynthetic activity in adult S. mansoni, on which research studies have been focused until now, was very low. We also discuss the participation of lipid metabolism in the constant renewal of the membrane complex which is essential to parasitism by S. mansoni.     

Immunohistochemical assessment of CD25 is equally sensitive and diagnostic in mastocytosis compared to flow cytometry

Background Systemic mastocytosis (SM) is a clonal myeloid disorder characterized by abnormal accumulation and growth of mast cells (MC) in internal organs. In most cases, the bone marrow is involved. Expression of CD25 in bone marrow MC, with or without coexpression of CD2, is an important minor SM criterion. So far, most studies have examined CD25‐expression on MC by flow cytometry. Materials and methods We examined the expression of CD25 in MC in patients with SM (n = 25) by immunohistochemistry (IHC) and compared these data with results obtained by flow cytometric assessment of CD25‐expression. In addition, we compared CD25‐staining results with that obtained with an antibody against CD2. Results In a majority of all patients (> 80%), CD25 was detectable by both staining techniques. However, in one patient, CD25 was only detectable on MC by IHC, but not by flow cytometry, and in two patients in whom IHC could not be applied because of lack of compact MC infiltrates, flow cytometry revealed aberrant expression of CD25. The antibody against CD2 produced diagnostic staining results in a smaller group of patients (flow cytometry: 65%; IHC: 28% of SM cases) compared to CD25 (> 80%). Conclusions CD25‐IHC is equally diagnostic and sensitive in SM compared to flow cytometry and thus can be recommended as a diagnostic test. Our data also suggest that the diagnostic value of CD25 exceeds that of CD2, and that optimal assessment of CD25‐expression in neoplastic MC in all patients requires the application of both techniques, flow cytometry and IHC.     

利用RT-PCR检测SM22基因在胃癌及正常组织中表达差异的生物学意义

目的:检测SM22(smoothmuscle22)mRNA在人胃癌及正常组织中的表达水平,探讨SM22基因与胃癌发生的关系,为进一步鉴定胃癌早期诊断筛查的标志物提供理论依据。方法:应用半定量RT-PCR检测42例胃癌组织及14例胃正常组织中SM22mRNA的表达水平并比较其差异。结果:在胃癌组织SM22mRNA的阳性表达率为92.86%(39/42),在正常组织中的阳性表达率为71.43%(10/14),差异无统计学意义(P>0.05)。半定量光密度计数后SM22mRNA表达量在胃癌组织和正常组织中分别为0.86±0.14和0.32±0.22,差异有统计学意义(P<0.01)。在14对胃癌与正常配对标本中,有10对胃癌及正常组织中SM22mRNA均表达阳性而且在肿瘤组织中表达量明显高于正常组织,有4对标本中SM22mRNA只在胃癌组织中表达而在正常组织中表达阴性。结论:SM22mRNA在胃癌组织中的表达量高于正常组织,提示其在胃癌发生发展中可能起一定作用。     

Width and depth of resection for small colorectal polyps: hot versus cold snare polypectomy

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