Myoblast fusion in Drosophila melanogaster is mediated through a fusion-restricted myogenic-adhesive structure (FuRMAS).

During myogenesis in Drosophila embryos, a prominent adhesive structure is formed between precursor cells and fusion-competent myoblasts (fcms). Here, we show that Duf/Kirre and its interaction partners Rols7 (found in founder myoblasts and growing myotubes) and Sns (found in fcms) are organized in a ring-structure at the contact points of fcms with precursor cells, while cytoskeletal components like F-actin and Titin are centered in this ring in both cell types. The cytoplasmic protein Blow colocalizes with the actin plugs in fcms after cell adhesion. Furthermore, the requirement of additional as yet unidentified components was demonstrated by using mammalian C2C12 myoblasts. In this study, we propose that the fusion-restricted myogenic-adhesive structure (FuRMAS) is pivotal in linking cell adhesion as well as local F-actin assembly and dynamics to downstream events that ultimately lead to plasma membrane fusion. Moreover, we suggest that the FuRMAS may restrict the area of membrane breakdown.     

Synthesis of 4‐[18F]fluoroiodobenzene and its application in sonogashira cross‐coupling reactions

The first application of a Sonogashira cross‐coupling reaction in ¹⁸F chemistry has been developed. The reaction was exemplified by the cross‐coupling of terminal alkynes (ethynylcyclopentyl carbinol 6 , 17α‐ethynyl‐3,17β‐estradiol 7 and 17α‐ethynyl‐3‐methoxy‐3,17β‐estradiol 8 ) with 4‐[¹⁸F]fluoroiodobenzene. 4,4′‐Diiododiaryliodonium salts were used as precursors for the synthesis of 4‐[¹⁸F]fluoroiodobenzene, enabling the convenient access to 4‐[¹⁸F]fluoroiodobenzene in 13–70% yield using conventional heating or microwave activation. The Sonogashira cross‐coupling of 4‐[¹⁸F]fluoroiodobenzene with terminal alkynes gave the corresponding 4‐[¹⁸F]fluorophenylethynyl‐substituted compounds [¹⁸F]‐9 , [¹⁸F]‐10 and [¹⁸F]‐13 in yields up to 88% within 20 min of starting from 4‐[¹⁸F]fluoroiodobenzene. Copyright © 2003 John Wiley & Sons, Ltd.     

Relationship between apoptosis and proliferation in secondary tumors of the brain

A correlation between apoptosis and proliferation in astrocytomas and oligodendrogliomas, but not in glioblastomas, has been previously reported. An index for apoptosis and proliferation was established for each tumor in a series of 20 brain metastases, and its correlation was studied using the Spearman rank correlation test. Apoptosis index (AI) ranged between 1 and 78% (mean ± SD: 11.48 ± 16.4). Proliferation index (PI) ranged between 2.4 and 21% (mean ± SD: 8.23 ± 4.8). When the relationship between AI and PI was studied, a clear correlation was found (r: 0.8965, 95% CI: 0.74–0.95; P < 0.0001). Therefore, it is concluded that a clear correlation exists between proliferation and apoptosis in secondary tumors of the brain.     

Whole-Body [18F]FDG PET in the Management of Metastatic Brain Tumours

Summary Background To determine its roles in the diagnosis and the systemic evaluation of metastatic brain tumours, whole-body positron emission tomography (PET) using [¹⁸F]FDG was performed in 20 consecutive patients. Methods  All patients were thought to be suffering or needing to be differentiated from metastatic brain tumours. Nine patients had multiple brain lesions; six were older and showed a rim-enhancing lesion with surrounding oedema; seven had homogeneously enhancing periventricular lesion(s) on computed tomography (CT) and/or magnetic resonance (MR) imaging, thought to be central nervous system lymphomas. Two patients had skull mass(es) and two patients had a solid mass suspected to be, respectively, a haemorrhagic metastasis and a metastatic malignant melanoma. All of them received whole-body [¹⁸F]FDG PET and conventional systemic work-up for metastasis in order to compare the results of the two methods. Results  Metastatic brain tumours were diagnosed on whole-body [¹⁸F]FDG PET in eleven patients who had extracranial and intracranial hypermetabolic lesions. In nine of these, a conventional work-up also detected primary lesions which on whole-body [¹⁸F]FDG PET were seen to be hypermetabolic foci. Systemic lymph node metastases were detected by whole-body [¹⁸F]FDG PET only in two patients and histological diagnosis was possible by biopsy of lymph nodes rather than of brain lesions. In the remaining nine patients who had only intracranial hypermetabolic foci, histological diagnosis was made by craniotomy or stereotactic biopsy. It was confirmed that seven of nine patients were suffering from a primary brain tumour and two from metastatic carcinoma. None of the nine showed evidence of systemic cancer on conventional work-up. Histological diagnoses of the primary brain tumours were four cases of primary central nervous system lymphoma and one each of multifocal glioblastoma, Ewing's sarcoma, and cavernous angioma.  Patients felt no discomfort during the whole-body [¹⁸F]FDG PET procedure and there were no complications. The false negative rate in [¹⁸F]FDG PET and in conventional work-up was 15.4% and 30.7% respectively. There were no false positives on either [¹⁸F]FDG PET or conventional work-up. Conclusion  It is suggested that whole-body [¹⁸F]FDG PET is a safe, reliable, and convenient method for the diagnosis and systemic evaluation of patients thought to be suffering or needing to be differentiated from a metastatic brain tumour.     

The relation between conduction velocity and axonal length

Motor evoked potentials (MEPs) obtained by electrical root stimulation and F waves were used to examine the proximal nerve conduction velocity (CV) to tibialis anterior (TA), extensor digitorum brevis (EDB), flexor carpi radialis (FCR), and abductor pollicis brevis (APB) muscles in 40 humans. By subtracting motor latencies obtained by stimulating the peripheral nerve at the same point from the F-wave and MEP latencies, we could measure the CV over identical proximal segments. It was found that proximal CV to TA and FCR was significantly higher than to EDB and APB, respectively. Combining the data of the proximal CV to all four muscles in relation with axonal length resulted in a highly significant inverse relationship (r² = 0.77). Thus the axonal length explained to a large extent the higher CV of the arm nerves and also the inverse relation between body height and CV. The distal CV was always lower than proximal CV; however, there was no support for an additional effect of this gradient in explaining the relationship between CV and height since it was constant for all body heights. © John Wiley & Sons, Inc.     

上调Mg2+/Mn2+依赖性蛋白磷酸酶1F表达对鼻咽癌HONE-1细胞增殖和迁移的影响

目的 探讨上调Mg²⁺/Mn²⁺依赖性蛋白磷酸酶1F（PPM1F）对鼻咽癌HONE-1细胞增殖、迁移的影响,并阐明其作用机制。 方法 鼻咽癌HONE-1细胞分为pcDNA3.1组（转染pcDNA3.1质粒）和pcDNA3.1-Flag-PPM1F组（转染pcDNA3.1-Flag-PPM1F质粒）。实时荧光定量PCR（RT-qPCR）法和Western blotting法检测2组细胞中PPM1F和E-钙黏蛋白（E-cadherin）mRNA及蛋白表达水平,CCK-8法和克隆形成实验检测2组细胞增殖活性和克隆形成率,细胞划痕实验检测2组细胞划痕愈合率,Transwell实验检测2组细胞中迁移细胞数。 结果 与pcDNA3.1组比较,pcDNA3.1-Flag-PPM1F 组细胞中PPM1F mRNA表达水平明显升高（P<0.01）,且PPM1F蛋白表达量明显增加,细胞中E-cadherin mRNA和蛋白表达水平明显升高（P<0.01）,细胞增殖活性、克隆形成率和划痕愈合率明显降低（P<0.05或P<0.01）,迁移细胞数明显减少（P<0.05）。 结论 上调PPM1F表达能够抑制鼻咽癌HONE-1 细胞增殖和迁移,其机制可能与细胞间的黏附作用有关。     

嵌合抗CD20抗体片段F(ab'')2的表达及活性

目的 :为了简化生产步骤 ,提高抗体蛋白的生物活性 ,探索在工程菌体内直接进行抗CD2 0F(ab’) 2 的高效率分泌性表达。方法 :采用单因素考察法优化培养条件 ,使蛋白G柱和S2 0 0 HR分子筛柱分离纯化目的蛋白 ,用MTT法检测抗CD2 0F(ab’) 2 抑制Daudi细胞体外生长的活性。结果 :发现用论文所选定的最适培养条件 ,抗CD2 0F(ab’) 2 的产量有了明显提高 ,从1 9～ 2 .2mg L达到了 3 7～ 4 3mg L ,F(ab’) 2 在表达产物中所占的比例也从 9 7%～ 13 2 %提高到了 38 1%～ 4 6 8% ;使用S2 0 0 HR分子筛柱对蛋白G柱亲和纯化后的产物进一步分离纯化 ,可以使F(ab’) 2 的纯度达到 85 %以上 ;MTT法检测结果证明F(ab’) 2 抑制Daudi细胞生长的IC50 值为 14 6 μg ml,而Fab’为 39 5 μg ml。 结论 :实现了抗CD2 0F(ab’) 2 在工程菌体内的高效率分泌性表达 ,而且所表达的抗CD2 0F(ab’) 2 比抗CD2 0Fab’具有更强的抑制Daudi细胞体外生长的能力     

Differential regulation of cytokine genes in gingival epithelial cells challenged by Fusobacterium nucleatum and Porphyromonas gingivalis

IL-8 mRNA in human gingival epithelial cells (HGECs) is up-regulated by Fusobacterium nucleatum, and up-/down-regulated by Porphyromonas gingivalis in a complex interaction in the early stages (< or = 4 h) after infection. The mechanisms involved in this regulation in response to F. nucleatum and/or P. gingivalis infection, and identification of co-regulated cytokine genes, are the focus of this investigation. Heat, formalin or protease treatment of F. nucleatum cells attenuated the IL-8 mRNA up-regulation. NF-kappaB, mitogen-activated protein kinase (MAPK) p38 and MAPK kinase/extracellular signal-regulated kinase (MEK/ERK) pathways were involved in IL-8 mRNA induction by F. nucleatum. Pretreatment of P. gingivalis with heat, formalin or protease enhanced IL-8 mRNA induction. NF-kappaB, MARK p38, and MEK/ERK pathways were also involved in this induction. In contrast, down-regulation of IL-8 mRNA by P. gingivalis involved MEK/ERK, but not NF-kappaB or MAPK p38 pathways. cDNA arrays analysis revealed that mRNA down-regulation by P. gingivalis is a specific reaction that only a number of genes, e.g. IL-1beta, IL-8, macrophage inflammatory protein-2alpha, and migration inhibitory factor-related protein-14, are affected based on examination of 278 cytokine/receptor genes. These data indicate that F. nucleatum and P. gingivalis trigger specific and differential gene regulation pathways in HGECs.     

Decreased prefrontal 5-HT2A receptor binding in subjects at enhanced risk for schizophrenia

The brain serotonin-2A receptor (5-HT_2AR) has been implicated in both the pathology of schizophrenia and the therapeutic action of atypical antipsychotics. However, little is known about the 5-HT_2AR status before the onset of schizophrenia and before the exposure to antipsychotics. We used [¹⁸F] altanserin and positron emission tomography (PET) in a pilot study of 6 individuals suspected to be at elevated risk for schizophrenia and seven age-matched controls to test the hypothesis that regional 5-HT_2AR binding is altered in the prodromal stages of schizophrenia. Distribution volume ratios (DVRs) as a proxy for 5-HT_2AR availability were significantly reduced in prefrontal cortex regions of at-risk subjects, implicating early abnormalities of serotonergic neurotransmission that antecede the onset of schizophrenia.     

L-选择蛋白在小鼠肝癌细胞高低转移株HCa-F、HCa-P的表达及与肿瘤转移潜能的相关性

目的　探讨经淋巴道转移的小鼠肝癌细胞高低转移株HCa F、HCa P淋巴道转移能力及与淋巴细胞归巢受体L 选择蛋白的相关性。方法　应用免疫印迹分析、RT PCR及流式细胞术检测小鼠肝癌HCa F、HCa P细胞表面L 选择蛋白的表达情况 ,再通过E 、P 、L 选择蛋白的抗体对细胞粘附实验的影响检测HCa F、HCa P细胞淋巴道转移潜能与L 选择蛋白的相关性。结果　L 选择蛋白在HCa F、HCa P细胞表面均有表达 ,且HCa F细胞的表达量明显高于HCa P细胞 (P <0 .0 1) ,HCa F细胞与淋巴结之间的粘附可被抗L 选择蛋白的抗体所阻断。结论　小鼠肝癌细胞高低转移株HCa F、HCa P细胞均表达L 选择蛋白 ,其程度与该细胞的淋巴道转移潜能正相关