Gz- and not Gi-proteins are coupled to pre-junctional μ-opioid receptors in bovine airways

We investigated the signal transmission pathway by which activation of μ-opioid receptors attenuates acetylcholine (ACh) release in bovine trachealis. Electrical stimulation (ES)-induced [³H]-ACh release was determined in bovine tracheal smooth muscle strips pre-incubated with either the Gi-protein inhibitor pertussis toxin (PTX, 500 ng/ml and 1 μg/ml) or the Gz-protein specific inhibitor arachidonic acid (AA, 10⁻⁶ M and 10⁻⁵ M) and then treated with DAMGO (D-Ala²,N-MePhe⁴,Gly-ol⁵-enkephalin) 10⁻⁵ M. Indomethacin 10⁻⁵ M was used to block AA cascade. The inhibitory effect of DAMGO on ES-induced [³H]-ACh release was PTX-insensitive, but, by contrast, ablated by AA in a concentration-dependent manner. AA 10⁻⁵ M alone reduced [³H]-ACh release, an effect that was prevented by iberiotoxin 10⁻⁷ M, suggesting an involvement of Ca²⁺-activated K⁺-channels. Western blot analysis consistently showed immunoreactive bands against a specific antibody anti-Gz-α subunit at ∼40 kDa, consistent with the presence of Gz-protein. The present findings suggest that in isolated bovine trachealis, activation of μ-opioid receptors inhibits ACh-release through a signal transmission pathway involving Gz-protein rather than Gi-protein.     

Mas在肿瘤中的研究进展

肾素-血管紧张素系统是肿瘤微环境的重要组成部分,在肿瘤代谢,血管生成和侵袭中发挥重要作用。Mas是该系统ACE2-Ang-(l-7)-Mas轴的重要成分,是一种重要的致癌基因,在多种癌组织中均表达。主要针对Mas在肿瘤形成中所涉及的相关通路进行简要综述。     

Wistar大鼠脑和脊髓微血管周细胞的分离、培养、鉴定及其功能差异的比较

探讨Wistar大鼠脑微血管周细胞（brain microvascular pericyte,BMP）和脊髓微血管周细胞（spinal cord microvascular pericyte,SCMP）之间的差异。运用超高速离心法获取脑和脊髓微血管,再用周细胞培养基培养,使周细胞爬出,然后用NG2和PDGFRβ鉴定周细胞,用鬼笔环肽着染F-actin,用流式细胞仪测定细胞周期,用免疫印记分析实验测定周细胞功能蛋白。结果表明：两种周细胞的形态有明显差异,BMP表达的F-actin显著多于SCMP,两种周细胞的细胞周期无显著差异,BMP相比于SCMP表达更多量的α-SMA、NG2和PDGFRβ。更多的了解两种周细胞的异同点,为研究其在中枢神经系统生理和病理状态下的作用奠定基础。     

MCPH1 deletion in a newborn with severe microcephaly and premature chromosome condensation

A newborn with severe microcephaly and a history of parental consanguinity was referred for cytogenetic analysis and subsequently for genetic evaluation. While a 46,XY karyotype was eventually obtained, premature chromosome condensation was observed. A head MRI confirmed primary microcephaly. This combination of features focused clinical interest on the MCPH1 gene and directed genetic testing by sequence analysis and duplication/deletion studies disclosed a homozygous deletion of exons 1–11 of the MCPH1 gene. This case illustrates a strength of standard cytogenetic evaluation in directing molecular testing to a single target gene in this disorder, allowing much more rapid diagnosis at a substantial cost savings for this family.     

Evaluation of three recombinant Leishmania infantum antigens in human and canine visceral leishmaniasis diagnosis

Visceral leishmaniasis (VL) is a neglected disease and is fatal if untreated. Dogs serve as reservoirs for Leishmania infantum (syn. L. chagasi) due to their susceptibility to infection and high skin parasitism. Therefore, VL control in Brazil involves the elimination of seropositive dogs, among other actions. However, the most frequently used serological tests have limitations regarding sensitivity and specificity. In this study, we have selected three Leishmania antigens (C1, C8 and C9) and have produced them as recombinant proteins using pET-28a-TEV vector and Escherichia coli BL-21 as expression system. When tested in ELISA with human samples, the C9 antigen was the one showing the most promising results, with 68% sensitivity and 78% specificity. When testing canine samples, the C1, C8 and C9 antigens showed a sensitivity range from 70% to 80% and specificity range from 60% to 90%. The C1 antigen presented higher sensitivity (80%) and the C8 antigen presented higher specificity (90%). Due to it, we decided to mix and test C1 and C8 antigens together, resulting in the C18 antigen. The mix also yielded high percentages of detected symptomatic and asymptomatic dogs however it did not improve the performance of the diagnostic. Comparison of our tests with the tests recommended by the Brazilian Ministry of Health revealed that our antigens’ sensitivities and the percentage of detected asymptomatic dogs were much higher. Our results suggest that the C1, C8, C18 and C9 recombinant proteins are good antigens to diagnose canine visceral leishmaniasis and could potentially be used in screening tests. To diagnose human visceral leishmaniasis, the C9 antigen presented reasonable results, but more optimization must be performed for this antigen to provide better performance.     

Caspase-9和Survivin在肝癌组织中的表达及意义

目的探讨Caspase-9和Survivin在肝细胞癌(HCC)患者肝癌组织中的表达及其临床意义。方法应用免疫组织化学SP法检测92例肝癌患者肝癌组织及其对应癌旁正常肝组织中Caspase-9和Survivin的表达,并分析其表达与HCC临床恶性生物学行为的相关性。组间比较采用卡方检验,相关性分析采用Spearman等级相关法。结果 Caspase-9在肝癌组织中的表达明显低于癌旁组织,而Survivin在肝癌组织中的表达明显高于癌旁组织,差异均具有统计学意义(χ2=6.48、7.05,P0.05)。在TNM分期Ⅲ~Ⅳ期、门静脉癌栓、淋巴结转移的肝癌组织中Survivin的阳性表达率明显增高(χ2=5.07、6.18、8.29,P0.05),而在其他分组中比较差异无统计学意义;在病理分级Ⅲ~Ⅳ级的肝癌组织中Caspase-9的阳性表达率明显降低(χ2=7.63,P0.05),而在其他分组中比较差异无统计学意义。结论 Caspase-9低表达和Survivin异常高表达均参与肝癌的发生过程,Caspase-9低表达可能与肝癌细胞恶性分化密切相关,而Survivin高表达与肝癌的浸润或远处转移等恶性发展密切相关。     

转化生长因子-β1对心房结构重构及细胞骨架蛋白的影响

心房颤动是临床上最常见的持续性心律失常。大量研究发现,心房颤动的发生发展与心房结构重构密切相关,而心房纤维化是最主要的结构重构改变。转化生长因子-β1是心房颤动纤维化重构中重要的致纤维化因子,不仅能引起细胞间质重构,还能影响心肌细胞骨架重塑及相关骨架蛋白表达异常。特别是使心脏特异性肌动蛋白交联蛋白α-actinin-2表达增加。细胞骨架蛋白参与了结构重构改变。现对转化生长因子-β1对心房结构重构及心房肌细胞骨架蛋白的影响进行综述。