整合素在药物性牙龈增生中的表达研究

目的:检测整合素α1、α2和β1在来源于药物性牙龈增生(drug-induced gingival overgrowth,DIGO)患者的牙龈成纤维细胞中的表达水平变化,探讨其与DIGO胶原聚集的相关性.方法:采用免疫组织化学法和实时定量PCR分别检测整合素α1、α2和β1在来源于DIGO和正常人群牙龈组织和成纤维细胞中的表达水平.结果:整合素α1在DIGO牙龈成纤维细胞中的表达水平显著性低于其在正常牙龈成纤维细胞中的表达水平(P＜0.01).而整合索α2和β1在2组牙龈成纤维细胞中的表达水平无显著性差异.结论:整合素α1在DIGO牙龈成纤维细胞中的低表达可能与胶原聚集相关.     

Influx and Efflux Transporters Contribute to the Increased Dermal Exposure to Active Metabolite of Regorafenib After Repeated Oral Administration in Mice

The multikinase inhibitor regorafenib, which is a standard treatment for certain cancer patients after disease progression following other approved therapies, exhibits delayed-onset dermal toxicity. Here, we aimed to clarify the mechanisms that contribute to the increased dermal exposure to active metabolite M-5 of regorafenib after repeated oral administration. The dermal concentration of M-5 at 24 h after the last 5 oral administrations of regorafenib in mdr1a/1b/bcrp^-/- mice was more than 190 times that in wild-type mice. The skin-to-plasma concentration ratio of M-5 in mdr1a/1b/bcrp^-/- was also higher than in wild-type mice, suggesting possible involvement of P-glycoprotein and breast cancer resistance protein in regulating the dermal distribution. The area under the plasma concentration-time curve values of M-5 and its precursor M-2 in plasma of mdr1a/1b/bcrp^-/- were at most 26 and 3 times those in wild-type mice, respectively. Interestingly, repeated administration of regorafenib markedly increased the area under the plasma concentration-time curve of M-5 in plasma, but not liver, compared with a single dose. Intravenous administration of M-5 dose-dependently reduced the liver-to-plasma concentration ratio. Our results indicate that hepatic uptake of M-5 may partially explain the accumulation of M-5 in the systemic circulation, but multiple factors, including influx and efflux transporters, are involved in determining dermal exposure to M-5.     

Daphnetin inhibits high glucose-induced extracellular matrix accumulation,oxidative stress and inflammation in human glomerular mesangial cells

Diabetic nephropathy (DN) is one of the most common causes of end-stage renal disease (ESRD). Oxidative stress and inflammation have been documented to play important roles in the pathogenesis of DN. Daphnetin, a natural coumarin compound, possesses antioxidant and anti-inflammatory activities. However, the role of daphnetin in DN has not yet been investigated. The aim of the present study was to explore the function of daphnetin in DN and the underlying mechanism in vitro. Our results demonstrated that daphnetin alleviated cell proliferation induced by high glucose (HG) in human mesangial cells (MCs). Daphnetin strikingly reduced reactive oxygen species (ROS) and malonaldehyde (MDA) levels, and induced the superoxide dismutase (SOD) activity in HG-stimulated MCs. Besides, the production of TNF-α, IL-1β, IL-6, fibronectin (FN) and collagen IV (Col IV) was also inhibited by daphnetin in HG-stimulated MCs. In addition, daphnetin enhanced the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2) and inhibited the levels of p-Akt and p-p65 in HG-stimulated MCs. The results indicated that daphnetin inhibited HG-induced oxidative stress, inflammatory response, and ECM accumulation in human MCs. The effect is partially mediated by Nrf2/keap1 and Akt/NF-κB pathways. The findings suggested that daphnetin might be a therapeutic or preventive agent for DN.     

Glycyrrhizin attenuates tissue injury and reduces neutrophil accumulation in experimental acute pancreatitis

Leukocyte infiltration and acinar cell injury are characteristic features of acute pancreatitis (AP). However, the signaling pathways regulating inflammation and accumulation of leukocytes into pancreas tissue remains poorly elucidated. In the current study, we investigated the effects of Glycyrrhizin (GZ) on cerulein-induced AP in mice. AP was induced in male C57BL/6 by intraperitoneal injection of 50 μg/kg cerulein hourly, with a total of 7 times. 1 hour after the last injection of cerulean, mice were treated with either 35 or 70 mg/kg of GZ. Serum amylases and lipases were measured using automated chromogenic assay, MCP-1 and MIP-2 concentrations were measured in the serum by ELISA, and the number of infiltrated inflammatory cells in the pancreas were evaluated by flow cytometry. We found that GZ treatment resulted in reduction (i) both amylase and lipase activities, (ii) the serum levels of both MCP-1 and MIP-2; and (iii) markedly attenuated cerulein-induced histopathological alternations and water contents. Furthermore, we observed that GZ significantly decreased the number of infiltrated monocytes and neutrophils into the pancreas tissue. In conclusion, we demonstrate that GZ attenuates AP signs and inhibits inflammatory cell recruitments into pancreas.     

高血压病并发腹型肥胖的中医临床分析

目的:探讨高血压病并发腹型肥胖的发生情况及其中医证型分布。方法:选择符合条件的高血压病患者128例,统计其年龄、性别、血压分级、危险分层、体重指数、腰围、腰身指数及中医分型等数据,用Excel软件及SPSS17.0统计软件进行分析。结果:高血压病患者中腹型肥胖者占84.38%。高血压并发腹型肥胖者的中医证型依次是瘀血型>痰湿壅盛型>阴阳两虚型>阴虚阳亢型>肝火亢盛型。在体重指数、腰围、腰身指数与中医分型的相关性上,痰湿壅盛型与其他四型比较差异有统计学意义(P<0.05)。结论:高血压病并发腹型肥胖时痰湿壅盛型及瘀血型偏多。痰湿壅盛型与高血压并发腹型肥胖关系密切,可为临床提出预警。     

Multiple Regions of Kaposi’s Sarcoma-Associated Herpesvirus ORF59 RNA are Required for Its Expression Mediated by Viral ORF57 and Cellular RBM15

KSHV ORF57 (MTA) promotes RNA stability of ORF59, a viral DNA polymerase processivity factor. Here, we show that the integrity of both ORF59 RNA ends is necessary for ORF57-mediated ORF59 expression and deletion of both 5’ and 3’ regions, or one end region with a central region, of ORF59 RNA prevents ORF57-mediated translation of ORF59. The ORF59 sequence between nt 96633 and 96559 resembles other known MTA-responsive elements (MREs). ORF57 specifically binds to a stem-loop region from nt 96596–96572 of the MRE, which also binds cellular RBM15. Internal deletion of the MRE from ORF59 led to poor export, but accumulation of nuclear ORF59 RNA in the presence of ORF57 or RBM15. Despite of being translatable in the presence of ORF57, this deletion mutant exhibits translational defect in the presence of RBM15. Together, our results provide novel insight into the roles of ORF57 and RBM15 in ORF59 RNA accumulation and protein translation.     

Determinants of spontaneous mutation in the bacterium Escherichia coli as revealed by whole-genome sequencing

A complete understanding of evolutionary processes requires that factors determining spontaneous mutation rates and spectra be identified and characterized. Using mutation accumulation followed by whole-genome sequencing, we found that the mutation rates of three widely diverged commensal Escherichia coli strains differ only by about 50%, suggesting that a rate of 1–2 × 10⁻³ mutations per generation per genome is common for this bacterium. Four major forces are postulated to contribute to spontaneous mutations: intrinsic DNA polymerase errors, endogenously induced DNA damage, DNA damage caused by exogenous agents, and the activities of error-prone polymerases. To determine the relative importance of these factors, we studied 11 strains, each defective for a major DNA repair pathway. The striking result was that only loss of the ability to prevent or repair oxidative DNA damage significantly impacted mutation rates or spectra. These results suggest that, with the exception of oxidative damage, endogenously induced DNA damage does not perturb the overall accuracy of DNA replication in normally growing cells and that repair pathways may exist primarily to defend against exogenously induced DNA damage. The thousands of mutations caused by oxidative damage recovered across the entire genome revealed strong local-sequence biases of these mutations. Specifically, we found that the identity of the 3′ base can affect the mutability of a purine by oxidative damage by as much as eightfold.A complete understanding of the evolution and stability of the genome requires that the determinants of spontaneous mutation be identified and characterized. Among the variety of mistakes that can occur during DNA transactions, four sources of sequence variation appear to dominate in prokaryotes: intrinsic DNA polymerase errors, endogenously induced DNA damage, DNA damage induced by exogenous agents, and the activities of error-prone polymerases. This conclusion is based on changes in the rates and spectra of mutations that occur when genes affecting these processes are deleted or amplified. In particular, loss of a DNA repair pathway often gives a mutator phenotype, indicating that the pathway of interest exerts an important limitation on spontaneous mutation (1). However, investigations of the mutagenic impact of various DNA repair pathways have relied almost exclusively on reporter genes, leaving open the possibility that the results are biased by the particular features of the selected loci. This concern can be avoided by allowing mutations to accumulate nonselectively in DNA repair-defective strains and identifying the resulting sequence changes by whole-genome sequencing (WGS). Although this approach may miss rare but interesting mutational processes, it can reveal the overall threats to genomic stability and identify features, such as local sequence context, that influence mutational frequencies. Surprisingly, this technique has been used with the eukaryote Caenorhabditis elegans (2) but has not been extensively applied to prokaryotes.The mutation accumulation (MA) protocol involves establishing multiple clonal populations from a single founder and then repeatedly passing the lines through single-individual bottlenecks (3, 4), which in bacteria is achieved easily by streaking for single colonies on agar medium. This procedure allows mutations to accumulate in an unbiased manner with a minimum of selective pressure. After a sufficient number of generations have occurred, the genomes are sequenced, and mutations are identified. Using this technique, we recently determined the intrinsic mutation rates and mutational spectra of repair-proficient strains of Escherichia coli and Bacillus subtilis and documented the mutational impact of the loss of the major error-correcting system, mismatch repair (MMR) (5–7). In the studies reported here we concentrate on E. coli, first asking if other commensal strains of E. coli have the same mutation rate and spectrum as our K12 strain and whether changing the growth medium influences mutation. Then we determined the mutational effects of the loss of several important DNA repair pathways. Our major conclusion is that, under the conditions of our experiments, mutation rates and spectra are nearly impervious to the loss of DNA repair functions except for those that deal with oxidative DNA damage. We also show that the mutagenicity of a major oxidative lesion, 7,8-dihydro-8-oxoguanine (8-oxoG), is highly dependent on the local sequence context.     

Lesions to the left lateral prefrontal cortex impair decision threshold adjustment for lexical selection

Patients with lesions in the left prefrontal cortex (PFC) have been shown to be impaired in lexical selection, especially when interference between semantically related alternatives is increased. To more deeply investigate which computational mechanisms may be impaired following left PFC damage due to stroke, a psychometric modelling approach is employed in which we assess the cognitive parameters of the patients from an evidence accumulation (sequential information sampling) modelling of their response data. We also compare the results to healthy speakers. Analysis of the cognitive parameters indicates an impairment of the PFC patients to appropriately adjust their decision threshold, in order to handle the increased item difficulty that is introduced by semantic interference. Also, the modelling contributes to other topics in psycholinguistic theory, in which specific effects are observed on the cognitive parameters according to item familiarization, and the opposing effects of priming (lower threshold) and semantic interference (lower drift) which are found to depend on repetition. These results are developed for the blocked-cyclic picture naming paradigm, in which pictures are presented within semantically homogeneous (HOM) or heterogeneous (HET) blocks, and are repeated several times per block. Overall, the results are in agreement with a role of the left PFC in adjusting the decision threshold for lexical selection in language production.