Maternal serum laeverin (aminopeptidase Q) measured in the first trimester of pregnancy does not predict preeclampsia

Objective: The aim of this study was to compare the laeverin level in maternal serum from first trimester (11–14 weeks) of pregnancy between normal pregnancies and pregnancies that later developed preeclampsia (PE).

Material and methods: This was a case-cohort study. The laeverin concentration was measured in cases with preterm PE (n?=?55), term PE (n?=?95), and a reference group of randomly selected women with normal pregnancy outcome (n?=?200) in stored serum samples collected from the double-test as part of the combined first trimester trisomy 21 screening program. The samples were thawed and analyzed for laeverin. The median gestational age at blood sampling was 77 days (range 57–96 days). Multiple regression analysis was performed to establish a normal median. Concentrations were converted to multiples of the median (MoM) and groups were compared using the Mann–Whitney U-test.

Results: In the reference group, laeverin was significantly correlated with gestational age (r?=?0.18, p?=?.01) and its concentration ranged from 41–393 µg/L. No significant differences in the median laeverin MoM were found between the reference group (1.01 MoM) and cases with preterm PE (0.98 MoM) or term PE (0.96 MoM).

Conclusions: First trimester maternal serum laeverin level cannot be used to predict preeclampsia.     

Assessment of biological activity of novel peptide analogues of angiotensin IV

Objectives Angiotensin IV (Ang IV) is a metabolite of angiotensin II which acts on specific AT₄ receptors identified as the enzyme insulin regulated aminopeptidase (IRAP). The transduction process of these receptors is unresolved, but Ang IV inhibits the aminopeptidase activity. Ang IV improves cognition in animal models thus there is a desire to develop metabolically stable analogues for further development. Methods Peptide analogues of Ang IV were obtained commercially or synthesised. Each peptide was tested in vitro for its ability to inhibit the aminopeptidase activity (IRAP) of mouse brain homogenates and for its effects on isolated rat uterine smooth muscle. Key findings [Des‐Val¹]‐Ang IV, acetylated‐Ang IV‐amide, Ang IV‐amide and [des‐His⁴]‐Ang IV all inhibited IRAP. [Sar¹, Ile⁸]‐Angiotensin II (10 µm ) had an effect greater than that of Ang IV or any of the other analogues studied. In isolated uterine smooth muscle, angiotensins II and IV induced contractions, which could be antagonised by an AT₁‐receptor antagonist. None of the novel peptides induced uterine smooth muscle contractions, but [Sar¹, des Arg²‐Gly⁸]‐angiotensin II showed significant antagonism of the contractile effects of angiotensin II and carboxyamide‐terminated Ang IV‐NH₂ showed antagonism of Ang IV‐induced contractions. Conclusions This study provides five novel inhibitors of IRAP worthy of assessment in behavioural models of learning and memory. The analogues are devoid of AT₁ receptor agonist properties, and the carboxyamide analogue presents an opportunity to elucidate the mechanism of action of Ang IV as, like Ang IV, it inhibits IRAP, but antagonises the effects of Ang IV on isolated smooth muscle.     

肝素对亮氨酸氨基肽酶测定的干扰评价

目的依据美国临床实验室标准化协会（CLSI）EP7-A2文件评价肝素对速率法测定亮氨酸氨基肽酶（LAP）的干扰,明确干扰物质带来的结果差异,确保分析方法性能符合临床要求。方法首先,使用2个不同厂家[北京利德曼生化股份有限公司（简称利德曼）、日本第一化学药品株氏会社（简称日本一化）]的试剂同时测定40例患者不抗凝血样本和肝素锂抗凝血样本的LAP,对2种样本的LAP结果进行分析,对有差异的结果进行干扰筛选分析。然后,分别进行＂配对差异＂试验和＂剂量效应＂试验以及肝素干扰LAP测定的浓度范围的评价。结果利德曼试剂测定2种样本LAP的结果有差异（P〈0.05）,日本一化试剂结果无差异（P〉0.05）。＂配对差异＂试验显示肝素对利德曼试剂测定低浓度LAP时存在干扰,而高浓度LAP不存在干扰。＂剂量效应＂试验结果显示肝素在不同浓度对LAP测定的干扰为非线性函数。初步判定LAP≤97 U/L时,肝素对利德曼试剂产生干扰;在LAP≥149 U/L时,其干扰效应不明显。结论当样本LAP≤97 U/L时,用利德曼试剂测定肝素锂抗凝样本LAP时会对检测结果产生正干扰。为保证LAP检测结果的准确性,如果继续使用利德曼LAP试剂,则需换用无抗凝的干燥管采集样本;如果继续使用肝素锂抗凝管采集样本,可换用日本一化LAP试剂。     

吉林汉族人群ERAP1基因3'UTR单核苷酸多态性与原发性高血压的关联性分析

目的:探讨ERAP1基因在高血压患者外周血中的表达,鉴定ERAP1基因3'UTR区与原发性高血压有关联的候选单核苷酸多态性(SNPs)位点。方法:在吉林地区汉族人群中选取高血压患者300例(高血压组)及正常对照者233名(对照组)进行病例对照研究,采用ELISA法检测研究对象的外周血中ERAP1表达水平,混池测序法鉴定ERAP1基因 3'UTR区SNPs位点,采用PCR测序的方法对研究对象进行测序分型。结果:高血压组患者外周血中ERAP1表达水平明显低于对照组 (P<0.05);ERAP1基因 3'UTR区鉴定出2个SNPs位点E20-790G >A和E20-816C >T,E20-816C >T位点的等位基因及基因型频数分布在高血压组和对照组间差异有统计学意义(P<0.05);排除混杂因素后,Logistic回归分析,E20-816C>T位点CT基因型频数在高血压组中显著降低(P<0.05,OR=0.145,95% CI:0.031-0.675)。结论:在吉林地区汉族人群中,ERAP1基因E20-816C>T位点多态性可能与原发性高血压有关联,高血压中CT基因型频数的降低可能与ERAP1表达下调有关联。     

冠状病毒的氨基肽酶N受体的研究进展

氨基肽酶N(Aminopeptidase N, APN)是一种锌离子依赖性膜结合II型的金属跨膜糖蛋白,其广泛存在于人和哺乳动物的多种组织细胞中。APN是多种冠状病毒的黏附性受体,参与冠状病毒的粘附与侵袭,与病毒感染密切相关。本文对多种冠状病毒(HCoV-229E、FCoV、CCoV、TGEV、PEDV)的APN受体的结构、功能、抑制剂等研究进展进行了总结,重点介绍了其作为人和猪冠状病毒功能受体的进展。本文为深入研究和应用冠状病毒APN受体提供参考。     

蛇床子素抑制膀胱癌细胞生长和侵袭的机制

目的：探讨蛇床子素对表皮生长因子受体酪氨酸激酶(epidermal growth factor receptor tyrosine kinase,EGFR-TPK)、基质金属蛋白酶(matrix-metalloproteinase-2,MMP-2)和氨肽酶N(aminopeptidase N,APN)的抑制作用,并阐明蛇床子素抑制膀胱癌T24细胞生长和侵袭的机制。方法：利用分光光度法研究蛇床子素对T24细胞EGFR-TPK,APN,MMP-2和caspase-3活性的影响,利用MTT法测定蛇床子素对膀胱癌T24细胞和人正常膀胱上皮细胞SV-HUC-1生长的抑制作用,采用Transwell小室法分析蛇床子素对膀胱癌T24细胞转移能力;Western印迹检测培养液中加入蛇床子素后,人膀胱癌细胞株T24中COX-2,VEGF及β-actin的表达;采用非放射性NF-κB凝胶迁移或电泳迁移率实验(electrophoretic mobility shift assay,EMSA)试剂盒测定T24细胞中NF-κB活性。结果：蛇床子素对EGFR-TPK,APN和MMP-2的半数抑制浓度(IC50)分别为(45.33±3.98),(28.21±3.23)和(8.11±0.54) µmol/L;随着蛇床子素浓度的增加,膀胱癌T24细胞生长抑制率不断增高,与空白对照组比较,差异均具有统计学意义(P<0.05);但SV-HUC-1细胞的生长并未受到明显的抑制;与空白对照组比较,蛇床子素组穿膜细胞的数减少(P<0.05);膀胱癌T24细胞中凋亡蛋白caspase-3活性显著增强(P<0.05);蛇床子素能够下调NF-κB,COX-2及VEGF的表达。结论：低毒性的蛇床子素可能通过降低EGFR-TPK,APN和MMP-2活性和NF-κB,COX-2及VEGF的表达,激活caspase-3活性的方式,对膀胱肿瘤细胞的侵袭、增殖和血管生成产生抑制作用。     

Isolation and characterization of aminopeptidase from Capnocytophaga granulosa ATCC 51502

There is evidence that enzymes from the genus Capnocytophaga play a role in dental calculus formation. Although most of the species in the genus produce aminopeptidases, there is a paucity of data on the purification and characterization of the enzyme, except in the case of Capnocytophaga gingivalis. The aim of this study was to purify aminopeptidase from culture supernatant of Capnocytophaga granulosa ATCC 51502, a new species of the genus. Purification was performed using ammonium sulfate fractionation and two chromatographic steps. The aminopeptidase was purified 158,433-fold with a yield of 12.0%. The enzyme appeared to be a trimer with a molecular mass of 270 kDa. The optimal pH of the aminopeptidase was 6.5 and its activity was completely inhibited by incubation at 50 degrees C for 10 min. The enzyme showed maximum specificity for basic amino acids (Arg and Lys) and also hydrolyzed noncharged amino acids (Met, Leu and Ala). Ca(2+), Zn(2+) and Fe(3+) activated the enzyme, while EDTA, Ag(+), Hg(+) and Cu(2+) inhibited it. These results suggest that aminopeptidase of C. granulosa is different from that of C. gingivalis but similar to aminopeptidase B.     

尿N-乙酰-β-D氨基葡萄糖酶、丙氨酸氨肽酶和α1-微球蛋白检测在唑来膦酸致肾损伤早期诊断作用

目的探讨尿N-乙酰-β-D氨基葡萄糖酶(NAG)、丙氨酸氨肽酶(AAP)和α1-微球蛋白(α1-MG)检测在唑来膦酸致肾损伤早期诊断中的作用。方法选取2012年2月至2014年7月沈阳军区总医院收治的100例应用唑来膦酸治疗的恶性肿瘤骨转移患者为研究对象。其中,男性48例,女性52例,年龄25~82岁,平均(60±11)岁。患者接受唑来膦酸注射液4 mg静脉滴注,1次/25~35 d,30 min滴完,连续应用3次。每次用药前和用药次日,留取患者清晨尿液及静脉血,检测并比较尿NAG、AAP、α1-MG和血肌酐(Scr)、尿素氮(BUN)水平。结果每次用药前、后比较尿NAG水平,差异均有统计学意义(P<0.05)。第1次用药前后,尿α1-MG水平比较,差异无统计学意义(P>0.05);而第2次和第3次用药前后,尿α1-MG水平比较,差异有统计学意义(P<0.05)。第1次和第3次用药前后,尿AAP水平比较,差异有统计学意义(P<0.05);而第2次用药前后,尿AAP水平比较,差异无统计学意义(P>0.05)。每次用药前后,Scr、BUN水平比较,差异均无统计学意义(P>0.05)。3次用药后,尿NAG、α1-MG水平组间比较,差异均有统计学意义(P<0.05);Scr、BUN水平组间比较,差异均无统计学意义(P>0.05)。结论唑来膦酸致肾损伤患者尿NAG、AAP和α1-MG水平变化早于血肌酐。尿NAG、AAP和α1-MG联合检测可作为肾损伤的早期诊断指标。