Isolation of a peptide that inhibits the posttranslational arginylation of proteins in rat brain

All eukaryotic cells contain enzymes that are able to catalyze the transfer of Arg from tRNA to the N-terminus of naturally short lived or damaged cytosolic proteins. For certain test proteins, it has been shown that the addition of Arg to the N-terminus leads to their degradation via the ubiquitin proteolytic pathway. The mechanisms used by cells for identifying proteins for arginylation and regulating arginylation are not known. The present study reports the isolation of a peptide from rat brain that is able to inhibit the arginylation of proteins in brain extracts. We suggest that this peptide is the physiological regulator of arginylation in rat brain.     

Induction of antibody responses to breast carcinoma associated mucins using synthetic peptide constructs as immunogens

A strategy for directing and enhancing B cell immune responses against synthetic peptide determinants has been developed in order to produce antibodies specifically against protein epitopes of clinical relevance. A peptide sequence based upon the MUC-1 mucin protein core was selected for this purpose since anti-MUC-1 antibodies have proven diagnostic application and therapeutic potential in human breast and ovarian cancer. Peptide constructs were synthesised co-linearly linking the immunodominant B cell determinant region, PDTRPAP, in the protein core of the MUC-1 mucin, to sequence 111 – 120 of influenza haemagglutinin A/X-31, a determinant recognised by T helper cells through association with MHC class II molecules. Induction of anti-MUC-1 antibodies to the B cell determinant region by immunisation with peptide was shown to be dependent upon both the presence and the position of the T cell determinant. In addition, haplotype mismatching with respect to the T cell determinant resulted in a significant lowering of the anti-MUC-1 antibody response in peptide construct immunised mice. These findings are relevant to the design of immunogens to produce antibodies against peptide epitopes of tumour associated proteins and glycoproteins.     

帕米磷酸钠和降钙素对人工关节磨损微粒引起单核细胞分泌溶骨性因子的影响

目的　探讨帕米磷酸钠和降钙素防治人工关节松动的可能性。方法　采集人体外周血 ,分离单核细胞 ,分组培养。实验分 4组 ,第 1组 :仅单核细胞 ,为对照组 ;第 2组 :单核细胞及微粒 ,为微粒组 ;第 3组 :单核细胞、微粒及帕米磷酸钠 (阿可达 ) ,为阿可达组 ;第 4组 :单核细胞、微粒及降钙素 (密钙息 ) ,为密钙息组。培养 48h后 ,检测细胞上清液中肿瘤坏死因子 (TNF) α、白细胞介素 (IL) 1和IL 6的含量。结果　微粒组的细胞上清液中溶骨性因子含量明显高于对照组 (P <0 .0 1) ;而阿可达组和密钙息组的溶骨性因子含量明显低于微粒组 (P <0 .0 1)。结论　阿可达和密钙息能有效地抑制微粒刺激单核巨噬细胞分泌溶骨性因子 ,从而间接抑制破骨细胞的活性。     

利多卡因对重型颅脑损伤患者血浆降钙素基因相关肽、钙调素及预后的影响

目的 为观察利多卡因对重型颅脑损伤患血浆降钙素基因相关肽、钙调素水平及其预后的影响。方法 将64例重型颅脑损伤患按随机原则分成利多卡因治疗组和常规治疗组，分别测定治疗前及治疗开始后第2、4、7天血浆CGRP、CaM含量，伤后6个月进行预后判断并进行比较分析。结果 重型颅脑损伤后患血浆CGRP水平下降而CaM水平升高，利多卡因治疗后可使上述改变显减轻并显改善患预后(P＜0.05)。结论 重型颅脑损伤后血浆CGRP水平下降而CaM水平升高，参与了继发性脑损伤的病理生理过程，早期应用利多可因治疗可通过对CGRP和CaM水平的影响，减轻继发性脑损伤，发挥脑保护作用。     

髂股静脉血栓形成血浆降钙素基因相关肽测定的临床意义

目的　探讨降钙素基因相关肽对髂股静脉血栓形成的影响。方法　回顾性分析 5 0例髂股静脉血栓形成患者降钙素基因相关肽 (CGRP)的水平 ,以及对比研究联合应用尿激酶和复方丹参注射液治疗前后CGRP的变化。结果　急性髂股静脉血栓形成患者均存在高水平的CGRP ,与对照组比较具有显著性差异 (P <0 0 1) ;治疗后 6h血浆CGRP水平明显升高 ,3d达到最高峰 ,15d接近正常水平。结论　CGRP可以作为髂股静脉血栓形成的诊断指标之一 ,联合应用尿激酶和复方丹参注射液对髂股静脉血栓形成有较好的疗效。     

Induction of antigen-specific isotype switching by in vitro immunization of human naive B lymphocytes

The use of in vitro immunization technology for the generation of human antigen-specific antibodies has essentially resulted in low affinity IgM antibodies, resembling an in vivo primary immune response. We now describe a detailed reproducible protocol for a two-step in vitro immunization, which yields isotype switched, antigen-specific human antibodies. The immunizing antigen was a 30aa synthetic peptide, containing both a B (15aa V3 peptide of the HIV-1) and a T helper cell epitope (15aa peptide from tetanus toxin). The immunization protocol includes: (i) a selection procedure of donors with a memory T cell response against tetatus toxoid; (ii) immunization of mature naive peripheral B lymphocytes in two distinct phases, involving a primary and a secondary step. None of the donors which were examined after primary 7immunization showed at any time an IgG anti-V3 specific antibody response, while all the donors showed an IgM response. After the secondary immunization step, anti-V3 antibodies of both IgM and IgG isotypes were detected. The switch frequency event was high among the tested donors (5/8).     

Fmoc/solid-phase synthesis of Tyr(P)-containing peptides through t-butyl phosphate protection

The synthesis is of Tyr(P)-containing peptides by the use of Fmoc-Tyr(PO₃Me₂)-OH in Fmoc/solid phase synthesis is complicated since, firstly, piperidine causes cleavage of the methyl group from the -Tyr(PO₃ Me₂)-residue during peptide synthesis and, secondly, harsh conditions are needed for its final cleavage. A very simple method for the synthesis of Tyr(P)-containing peptides using t-butyl phosphate protection is described. The protected phosphotyrosine derivative, Fmoc-Tyr(PO₃^tBu₂)-OH was prepared in high yield from Fmoc-Tyr-OH by a one-step procedure which employed di-t-butyl N,N-diethyl-phosphoramidite as the phosphorylation reagent. The use of this derivative in Fmoc/solid phase peptide synthesis is demonstrated by the preparation of the Tyr(P)-containing peptides, Ala-Glu-Tyr(P)-Ser-Ala and Ser-Ser-Ser-Tyr(P)-Tyr(P).     

支气管扩张症肺组织内降钙素表达的临床意义

目的　了解支气管扩张症肺组织降钙素 (CT)蛋白表达水平与其病变特点的关系。方法　应用免疫组化方法定量分析 4 5例支气管扩张症患者手术切除的肺组织 ,对其气道上皮内神经内分泌细胞 (NEC)计数 ,并与 19例无肺部疾患的尸检肺组织进行比较。结果　 2组均可见被染成棕红色的CT阳性细胞 ,它们分布于肺内各级支气管上皮细胞间 ,以支气管分叉处较多见。支气管扩张症组肺组织内5 0 0 0个上皮细胞中CT阳性细胞数为 (6 7.4 8± 11.0 3)个 ,非支气管扩张症组肺组织内CT阳性细胞数仅为 (5 .0 2± 1.0 0 )个 ,2组比较有非常显著性差异 (P <0 .0 0 1)。结论　支气管扩张症肺组织高水平CT表达可能与其慢性炎症改变有关 ,其局部CT表达增高可能系机体对支气管扩张病变的一种局部性代偿或调节机制。     

Diabetes alters μ and κ opioid binding in rat brain regions: comparison with effects of food restriction

Diabetic rats display changes in opioid pharmacology and brain regional levels of opioid peptides and prodynorphin mRNA. Previous investigations of opioid receptor binding, carried out in whole-brain homogenates, have, however, failed to detect changes. In the present study, quantitative autoradiography was used to measure μ and κ opioid receptor binding in discrete brain regions of streptozotocin-treated diabetic rats. Measurement was limited to regions that previously displayed opioid binding changes in chronically food-restricted rats, since our primary aim is to identify brain mechanisms that mediate adaptive responses to persistent metabolic need and adipose depletion. Diabetics displayed strong trends or statistically significant changes which matched seven of the thirteen binding changes observed in food-restricted rats. In no case did diabetics display changes in the opposite direction. The two statistically significant changes common to food-restricted and diabetic rats are increased κ binding in the medial preoptic area and decreased μ binding in the lateral habenula. The possible functional significance of these changes is discussed.