吴茱萸五加紫丁香甙含量分析

吴茱萸五加（Acauthopanax evodiaefodius Franch.)在我国南方各省分布较广,资源较丰富,为寻求新的药物资源,用反相高效液相色谱法对吴茱萸五加的化学成分进行了分析,发现其紫丁香甙含量较多,紫丁香甙药用价值较高,本分析方法分离效果好,简便,快速,准确度和精密度高,相对标准偏差为1．8％,平均回收率为98．4％。     

Effect of left atrial compliance on pulmonary artery pressure: a case report

Background

Pericardial tumours are unusual and may be difficult to characterise with imaging. They manifest as large, non-contractile, solid masses within the pericardium. Presenting symptoms include heart failure, arrythmias, sudden death, cyanosis and chest pain.

Case presentation

We describe a case of massive pericardial fibroma in a 52 year old woman, who presented with palpitations only.

Conclusion

We illustrate the different imaging modalities available to image this tumour prior to surgical resection, and indicate the strengths and weaknesses of each.     

阻塞性睡眠呼吸暂停低通气综合征血压变异性及运动心肺功能与病情的相关性分析

目的:探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)血压变异性及运动心肺功能与病情的相关性分析。方法:选取2017年2月～2018年11月期间我院收治的OSAHS患者119例为研究对象,根据每小时睡眠呼吸暂停次数(AHI)将患者分为轻度组(AHI:5～20次/h,n=45)、中度组(AHI:21～40次/h,n=39)、重度组(AHI:40次/h,n=35),检测所有研究对象的血压变异性及运动心肺功能,并作组间比较。采用Pearson积矩相关分析OSAHS患者血压变异性及运动心肺功能与病情的相关性。结果:OSAHS患者收缩压(SBP)昼、舒张压(DBP)夜以及中度组、重度组SBP夜均高于对照组(P0.05);重度组DBP夜以及中度组、重度组SBP昼、SBP夜高于轻度组(P0.05);重度组SBP夜、SBP昼、DBP夜高于中度组(P0.05);而各组DBP昼整体比较差异无统计学意义(P0.05)。OSAHS患者最大摄氧量占预计值百分比(VO2max%pred)、最大摄氧量峰值占预计值百分比(peak VO2%pred)、无氧阈值(AT)、摄氧量功率比值(VO2/WR)、呼吸储备(VEmax/MVV)均低于对照组,且随病情严重程度的增加而降低(P0.05),OSAHS患者二氧化碳通气当量(VE/VCO2)高于对照组,且随病情严重程度的增加而升高(P0.05)。Pearson积矩相关分析结果显示,OSAHS患者病情严重程度与SBP昼、SBP夜、DBP夜、VE/VCO2呈正相关(P0.05),与VO2max%pred、peakVO2%pred、AT、VEmax/MVV、VO2/WR呈负相关(P0.05),与DBP昼无相关性(P0.05)。结论:血压变异性及运动心肺功能指标可反映OSAHS患者病情严重程度,可考虑作为早期监测指标并参考指导治疗。     

Protective effect of nicotinamide on neuronal cells under oxygen and glucose deprivation and hypoxia/reoxygenation

Nicotinamide (vitamin B₃) reduces the infarct volume following focal cerebral ischemia in rats; however, its mechanism of action has not been reported. After cerebral ischemia and/or reperfusion, reactive oxygen species (ROS) and reactive nitrogen species may be generated by inflammatory cells through several cellular pathways, which can lead to intracellular calcium influx and cell damage. Therefore, we investigated the mechanisms of action of nicotinamide in neuroprotection under conditions of hypoxia/reoxygenation. Results showed that nicotinamide significantly protected rat primary cortical cells from hypoxia by reducing lactate dehydrogenase release with 1 h of oxygen-glucose deprivation (OGD) stress. ROS production and calcium influx in neuronal cells during OGD were dose-dependently diminished by up to 10 mM nicotinamide (p<0.01). This effect was further examined with OGD/reoxygenation (H/R). Cells were stained with the fluorescent dye 4,6-diamidino-2-phenylindole (DAPI) or antibodies against anti-microtubule-associated protein-2 and cleaved caspase-3. Apoptotic cells were studied using Western blotting of cytochrome c and cleaved caspase-3. Results showed that vitamin B₃ reduced cell injury, caspase-3 cleavage and nuclear condensation (DAPI staining) in neuronal cells under H/R. In addition, nicotinamide diminished c-fos andzif268 immediate-early gene expressions following OGD. Taken together, these results indicate that the neuroprotective effect of nicotinamide might occur through these mechanisms in this in vitro ischemia/reperfusion model.     

Critical Role for Perforin-, Fas/FasL-, and TNFR1-Mediated Cytotoxic Pathways in Down-Regulation of Antigen-Specific T Cells during Persistent Viral Infection

Viral persistence following infection with invasive strains of lymphocytic choriomeningitis virus (LCMV) can be achieved by selective down-regulation of virus-specific T lymphocytes. High viral burden in the onset of infection drives responding cells into functional unresponsiveness (anergy) that can be followed by their physical elimination. In this report, we studied down-regulation of the virus-specific CD8(+)-T-cell response during persistent infection of adult mice with LCMV, with emphasis on the role of perforin-, Fas/FasL-, or tumor necrosis factor receptor 1 (TNFR1)-mediated cytolysis in regulating T-cell homeostasis. The results reveal that the absence of perforin, Fas-ligand, or TNFR1 has no significant effect on the kinetics of proliferation and functional inactivation of virus-specific CD8(+) T cells in the onset of chronic LCMV infection. However, these molecules play a critical role in the homeostatic regulation of T cells, influencing the longevity of the virus-specific CD8(+)-T-cell population once it has become anergic. Thus, CD8(+) T cells specific to the dominant LCMV NP(396-404) epitope persist in an anergic state for at least 70 days in perforin-, FasL-, or TNFR1-deficient mice, but they were eliminated by day 30 in C57BL/6 controls. These effects were additive as shown by a deficit of apoptotic death of NP(396-404) peptide-specific CD8(+) T cells in mice lacking both perforin and TNFR1. This suggests a role for perforin-, FasL-, and TNFR1-mediated pathways in down-regulation of the antiviral T cell response during persistent viral infection by determining the fate of antigen-specific T cells. Moreover, virus-specific anergic CD8(+) T cells in persistently infected C57BL/6 mice contain higher levels of Bcl-2 and Bcl-XL than functionally intact T cells generated during acute LCMV infection. In the case of proapoptotic factors, Bax expression did not differ between T-cell populations and Bad was below the limit of detection in all samples. As expression of the Bcl-2 family members controls susceptibility to apoptosis, this finding may provide a molecular basis for the survival of anergic cells under conditions of prolonged antigen stimulation.     

DNA methylation establishment of CpG islands near maternally imprinted genes on chromosome 7 during mouse oocyte growth

The genome methylation is globally erased in early fetal germ cells, and it is gradually re‐established during gametogenesis. The expression of some imprinted genes is regulated by the methylation status of CpG islands, while the exact time of DNA methylation establishment near maternal imprinted genes during oocyte growth is not well known. Here, growing oocytes were divided into three groups based on follicle diameters including the S‐group (60–100 μm), M‐group (100–140 μm), and L‐group (140–180 μm). The fully grown germinal vesicle (GV)‐stage and metaphase II (M2)‐stage mature oocytes were also collected. These oocytes were used for single‐cell bisulfite sequencing to detect the methylation status of CpG islands near imprinted genes on chromosome 7. The results showed that the CpG islands near Ndn, Magel2, Mkrn3, Peg12, and Igf2 were completely unmethylated, but those of Peg3, Snrpn, and Kcnq1ot1 were hypermethylated in MII‐stage oocytes. The methylation of CpG islands near different maternal imprinted genes occurred asynchronously, being completed in later‐stage growing oocytes, fully grown GV oocytes, and mature MII‐stage oocytes, respectively. These results show that CpG islands near some maternally imprinted genes are not necessarily methylated, and that the establishment of methylation of other maternally imprinted genes is completed at different stages of oocyte growth, providing a novel understanding of the establishment of maternally imprinted genes in oocytes.     

Identification of New Genetic Risk Variants for Type 2 Diabetes

Although more than 20 genetic susceptibility loci have been reported for type 2 diabetes (T2D), most reported variants have small to moderate effects and account for only a small proportion of the heritability of T2D, suggesting that the majority of inter-person genetic variation in this disease remains to be determined. We conducted a multistage, genome-wide association study (GWAS) within the Asian Consortium of Diabetes to search for T2D susceptibility markers. From 590,887 SNPs genotyped in 1,019 T2D cases and 1,710 controls selected from Chinese women in Shanghai, we selected the top 2,100 SNPs that were not in linkage disequilibrium (r²<0.2) with known T2D loci for in silico replication in three T2D GWAS conducted among European Americans, Koreans, and Singapore Chinese. The 5 most promising SNPs were genotyped in an independent set of 1,645 cases and 1,649 controls from Shanghai, and 4 of them were further genotyped in 1,487 cases and 3,316 controls from 2 additional Chinese studies. Consistent associations across all studies were found for rs1359790 (13q31.1), rs10906115 (10p13), and rs1436955 (15q22.2) with P-values (per allele OR, 95%CI) of 6.49×10⁻⁹ (1.15, 1.10–1.20), 1.45×10⁻⁸ (1.13, 1.08–1.18), and 7.14×10⁻⁷ (1.13, 1.08–1.19), respectively, in combined analyses of 9,794 cases and 14,615 controls. Our study provides strong evidence for a novel T2D susceptibility locus at 13q31.1 and the presence of new independent risk variants near regions (10p13 and 15q22.2) reported by previous GWAS.     

Catalysis of creatine kinase refolding by protein disulfide isomerase involves disulfide cross-link and dimer to tetramer switch

Protein disulfide isomerase (PDI) functions as an isomerase to catalyze thiol:disulfide exchange, as a chaperone to assist protein folding, and as a subunit of prolyl-4-hydroxylase and microsomal triglyceride transfer protein. At a lower concentration of 0.2 microm, PDI facilitated the aggregation of unfolded rabbit muscle creatine kinase (CK) and exhibited anti-chaperone activity, which was shown to be mainly due to the hydrophobic interactions between PDI and CK and was independent of the cross-linking of disulfide bonds. At concentrations above 1 microm, PDI acted as a protector against aggregation but an inhibitor of reactivation during CK refolding. The inhibition effect of PDI on CK reactivation was further characterized as due to the formation of PDI-CK complexes through intermolecular disulfide bonds, a process involving Cys-36 and Cys-295 of PDI. Two disulfide-linked complexes containing both PDI and CK were obtained, and the large, soluble aggregates around 400 kDa were composed of 1 molecule of tetrameric PDI and 2 molecules of inactive intermediate dimeric CK, whereas the smaller one, around 200 kDa, was formed by 1 dimeric PDI and 1 dimeric CK. To our knowledge this is the first study revealing that PDI could switch its conformation from dimer to tetramer in its functions as a foldase. According to the observations in this research and our previous study of the folding pathways of CK, a working model was proposed for the molecular mechanism of CK refolding catalyzed by PDI.     

SSR alpha and associated calnexin are major calcium binding proteins of the endoplasmic reticulum membrane

GTP phosphorylation of rough microsomes in vitro is limited to four integral membrane proteins. Two of these, a phosphoprotein (pp90) and a phosphoglycoprotein (pgp35) were purified as a complex with two nonphosphorylated membrane glycoproteins, gp25H and gp25L. The authenticity of this complex was confirmed using two different purification procedures and by coimmunoprecipitation. By immunofluorescence a reticulated cytoplasmic network was revealed for the proteins which was similar to that for Louvard et al. (Louvard, D., Reggio, H., and Warren, G. (1982) J. Cell Biol. 92, 92-107) marker antisera which also recognized purified pp90 on immunoblots. Amino acid sequencing of peptides derived from pgp35 identified this protein as SSR alpha, an endoplasmic reticulum constituent as identified by cross-linking of translocating nascent chains (G?rlich, D, Prehn, S., Hartmann, E., Herz, J., Otto, A., Kraft, R., Wiedmann, M., Knespel, S., Dobberstein, B., and Rapoport, T. A. (1990) J. Cell Biol. 111, 2283-2294). The sequence of gp25H was determined from cDNA clones and was identical with SSR beta identified by G?rlich et al. (1990) as being tightly bound to SSR alpha. Sequencing of gp25L revealed no similarity of the deduced sequence with other proteins. However, pp90 revealed a high degree of sequence identity with the Ca(2+)-binding protein, calreticulin. 45Ca2+ overlay studies indicated that pp90 bound Ca2+ and the name calnexin is proposed. Surprisingly, pgp25 (SSR alpha) also bound Ca2+ although gp25H (SSR beta) and gp25L did not. Triton X-114 partitioning of the integral membrane proteins of rough microsomes suggested that pgp35 (SSR alpha) and calnexin were major Ca(2+)-binding proteins of the endoplasmic reticulum membrane. We propose that the function of the complex is to regulate Ca(2+)-dependent retention mechanisms for luminal proteins of the endoplasmic reticulum.