Role of Helix 8 in Dopamine Receptor Signaling

G protein-coupled receptors (GPCRs) are membrane receptors whose agonist-induced dynamic conformational changes trigger heterotrimeric G protein activation, followed by GRK-mediated phosphorylation and arrestin-mediated desensitization. Cytosolic regions of GPCRs have been studied extensively because they are direct contact sites with G proteins, GRKs, and arrestins. Among various cytosolic regions, the role of helix 8 is least understood, although a few studies have suggested that it is involved in G protein activation, receptor localization, and/or internalization. In the present study, we investigated the role of helix 8 in dopamine receptor signaling focusing on dopamine D1 receptor (D1R) and dopamine D2 receptor (D2R). D1R couples exclusively to Gs, whereas D2R couples exclusively to Gi. Bioinformatic analysis implied that the sequences of helix 8 may affect GPCR-G protein coupling selectivity; therefore, we evaluated if swapping helix 8 between D1R and D2R changed G protein selectivity. Our results suggest that helix 8 is not involved in D1R-Gs or D2R-Gi coupling selectivity. Instead, we observed that D1R with D2R helix 8 or D1R with an increased number of hydrophobic residues in helix 8 relative to wild-type showed diminished β-arrestin-mediated desensitization, resulting in increased Gs signaling.

Strategies to improve the writing quality of English abstracts in medical postgraduates′research papers / 医学研究生学报

In order to continuously improve the level of English abstracts for medical postgraduates , this paper introduces the definition, purpose, types, contents and writing strategies of English abstracts .It also introduces the writing difference and evolution of the word abstractand the writing tips of all kinds of abstracts , especially the structured abstract .In reference to international and do-mestic writing criteria , it points out the problems which should be paid attention to in writing English abstracts and tried to develop the students′consciousness in improving their level of writing English abstracts so that their thesis will be better recognized and cited by in -ternational experts , thus promoting the international academic exchanges as well as the development of China ′s medical undertakings .

Research progress of LncRNA and chemotherapy resistance in gastrointestinal neoplasms / 实用肿瘤学杂志

Gastrointestinal tumor chemotherapy resistance makes many patients be fail treatment,and its mechanism is unclear.The long-chain non-coding RNA(LncRNA)was found in the transcription,transcription and epigenetic,and other aspects of the regulation of the pathophysiology of the body.Many studies have found that LncRNA is also closely related to gastrointestinal cancer resistance drugs.LncRNA is not only closely related to the ten characteristics of the tumor,but it also regulates gastrointestinal cancer resistance by the impact of drug transporter,competitive endogenous RNA in the way of action,affecting tumor cell apoptosis,and regulating epi-thelial mesenchymal transition process.This article will review gastrointestinal cancer-related LncRNA and its participation in gastrointestinal resistance mechanism.

Research progress of LncRNA and chemotherapy resistance in gastrointestinal neoplasms / 实用肿瘤学杂志

Gastrointestinal tumor chemotherapy resistance makes many patients be fail treatment,and its mechanism is unclear.The long-chain non-coding RNA(LncRNA)was found in the transcription,transcription and epigenetic,and other aspects of the regulation of the pathophysiology of the body.Many studies have found that LncRNA is also closely related to gastrointestinal cancer resistance drugs.LncRNA is not only closely related to the ten characteristics of the tumor,but it also regulates gastrointestinal cancer resistance by the impact of drug transporter,competitive endogenous RNA in the way of action,affecting tumor cell apoptosis,and regulating epi-thelial mesenchymal transition process.This article will review gastrointestinal cancer-related LncRNA and its participation in gastrointestinal resistance mechanism.

miR-181d Inhibits Proliferation and Promotes Apoptosis in Colon Cancer Cells / 现代检验医学杂志

Objective To detect miR-181d expression levels in colon cancer cell lines,and to study the functions of miR-181d on colon cancer cell proliferation and apoptosis.Methods RT qPCR was employed to study miR-181d cxpression levels in colon cancer cell line HCT116,HT29,LoVo,SW480 and SW620 cells,as well as in colon normal epithelial cell line HIEC.miR-181d mimic and control were transfected into LoVo cells while miR-181d inhibitor and control were transfected into SW620 cells.qRT-PCR was performed to validate the transfection efficiency.MTT assay was performed to measure cell proliferation while flow cytometry was performed to detect cell cycle and apoptosis rate.Results miR-181d was universally downregulated in all colon cancer cell lines compared to the colon normal epithelial cell line HIEC (F=29.34,P＜0.01).Overexpression of miR-181d in LoVo cells significantly decreased in vitro cell proliferation rate (F=5.403,P＜0.01).Flow cytometry indicated that cells at S phase were greatly decreased (t=4.71,P＜0.05) and apoptotic cells were gready increased compared to the control cells (t=3.47,P＜0.05).On the contrary,inhibition of miR-181d in SW620 cells significantly promoted cell proliferation (F=20.82,P＜0.01).Cell cycle was accelerated with significant increase in S phase compared to the control cells (t=2.92,P＜0.05),whereas apoptosis rano was significantly decreased (t=4.14,P＜0.05).Conclusion miR-181d was universally downregulated in colon cancer cell lines compared to the normal epithelial cell line.miR-181d inhibits cell proliferation and induces apoptosis,thus functions as an tumor suppressive miRNA.

The relationship of plasma homocysteine and the polymorphism of MTHFR gene with brain infarction in type 2 diabetes mellitus / 中国糖尿病杂志

Objective To investigate the relationship of plasma homocysteine and the polymorphism of MTHFR gene with ischemic stroke in type 2 diabetes. Methods Serum Hcy ,folic acid and the polymorphism of MTHFR gene were compared among 81 T2DM patients with brain infarction (T2DM+BI) and 325 T2DM patients without brain infarction (T2DM ). Results All the genotypes of T2DM group and T2DM+BI group followed the hardy‐weinberg law. There was no significant difference in the frequency of mutant alleles (T) in site 677 of MTHFR gene and in frequency of TT genotype between the groups of T2DM and T2DM + BI (64.15% vs 60.15% and 42.5% vs 34.5% ,P > 0.05 ). The concentration of Hcy was significantly higher in patients with TT genotype than with CC genotype (14.4 ± 7.86) vs (10.58 ± 3.37)mmol/L(P<0.01). Conclusion There is no correlation between polymorphism of MTHFR gene and stroke in T2DM patients. The mutation of MTHFR C677T is associated with hyperhomocysteinemia.

Simultaneous determination of alpha-pinene, beta-pinene, eucalyptol and alpha-terpineolin in essential oil from Alpinia officinarum Hance by GC / 中国中药杂志

<p><b>OBJECTIVE</b>To establish a method for simultaneous determination of alpha-pinene, beta-pinene, eucalyptol and alpha-terpineolin in essential oil from Alpinia officinarum by GC.</p><p><b>METHOD</b>The essential oil was extracted by steam distillation. The determination was carried on with capillary column DB-1 (0.25 mm x 30 m, 0.25 microm). Temperature programs: 50 degrees C (hold 2 min) programmed to 130 degrees C (hold 3 min) at 8 degrees C x min(-1). The detector was FID. Inlet temperature was 230 degrees C. The detector temperature was 250 degrees C. Carrying gas was nitrogen (1.2 mL x min(-1)), split injection was conducted with split ratio of 10:1. Injection volumn was 1 microL.</p><p><b>RESULT</b>The linear ranges of alpha-pinene, beta-pinene, eucalyptol and alpha-terpineolin were 0.009-0.090 (r = 0.999 8), 0.009-0.091 (r = 0.999 8), 0.060 4-0.604 (r = 0.999 7) and 0.037 4-0.374 g x L(-1) (r = 0.999 5), respectively. The average recoveries (n = 9) of a-pinene, beta-pinene, eucalyptol and alpha-terpineolin were 96.2% (RSD 0.8%) and 96.7% (RSD 1.1%), 98.7% (RSD 1.1%) and 96.7% (RSD 2.2%), respectively.</p><p><b>CONCLUSION</b>The developed method is simple, quick and accurate, which is helpful to control the quality of A. officinarum.</p>