精氨酸修饰成纤维细胞生长因子21及修饰后蛋白体内稳定性和糖代谢调节作用的研究

成纤维细胞生长因子21(fibroblast growth factor21,FGF21)是2000年发现的一个不依赖胰岛素调节血糖的细胞因子,有望成为治疗糖尿病的候选药物.但是,野生型FGF21由于半衰期较短,在体内不稳定,从而影响其成药性.为提高FGF21的稳定性,本实验在FGF21的C端添加了2个精氨酸(arginine,Arg),命名为FGF21-2A,用Compute pI/Mw软件计算之后,等电点(isoelectric point,pI)从5.43上升到5.84,随后进行了蛋白质的表达、分离纯化、体内稳定性及糖代谢调节作用的研究.诱导表达后菌液的SDS-PAGE图经BandScan5.0分析后显示FGF21-2A的表达量相对于野生型FGF21提高了10.6%.家兔体内半衰期检测实验结果显示FGF21-2A的半衰期显著延长.GOD-POD法检测HepG2肝癌细胞葡萄糖吸收实验、糖尿病小鼠降血糖实验和肝糖原检测实验的结果证明,FGF21-2A的降糖效果得到了增强,并且持续时间相对于野生型FGF21显著延长.Real-time PCR结果发现,长期注射FGF21-2A显著提高了糖尿病小鼠肝脏内葡萄糖转运蛋白(GLUT)1和葡萄糖激酶(GK)mRNA的表达量,降低了葡萄糖-6-磷酸酶(G6P)的mRNA表达量,表明FGF21-2A调节糖代谢的机制与野生型FGF21一致.综上所述,精氨酸修饰的FGF21其蛋白质稳定性提高,进而增加了对血糖的调控效果,有望成为新型糖尿病药物.     

水分、氮肥及MeJA处理对白桦三萜积累特性的影响

以一年半生白桦幼树为试材,研究水分、氮肥和茉莉酸甲酯(MeJA)处理对白桦三萜物质积累的影响,并对白桦植株中三萜积累规律进行了探讨。结果表明:(1)白桦幼树植株中总三萜主要分布在茎皮和叶片,根皮中最低,平均含量分别为71.94、81.60和25.45mg.g-1;叶片中总三萜积累高峰出现在6、7月份,茎皮和根皮中总三萜积累高峰分别出现在8月份和7月份。(2)干旱胁迫早期(6月)中度和重度干旱胁迫显著促进了叶中总三萜积累,分别是对照的1.24和1.27倍。茎皮中,除7月水分胁迫处理显著高于对照外,其它各月份水分胁迫不利于茎皮中总三萜含量积累,干旱胁迫不利根皮中三萜积累。(3)施氮早期(6月)不利于三萜在叶片和根皮中积累,中后期(7～10月),氮肥处理对三萜积累有显著促进作用;而施氮早期(6～7月)促进茎皮中三萜积累作用。(4)MeJA喷施处理对叶片和根皮中三萜积累(7月～10月)均具有显著的促进作用,在积累高峰期分别是对照的1.42倍和1.52倍。(5)轻度干旱、氮肥均促进了白桦幼树株高的增长和生物量的积累,而MeJA处理对整株生物量的积累不利。     

Cd胁迫下不同耐性豆科植物根内活性氧产生与基因组DNA多态性变化

采用溶液培养法,研究了镉胁迫对绿豆和箭舌豌豆幼苗根基因组DNA多态性和活性氧产生的影响.结果表明:Cd胁迫降低了2种植物根尖基因组DNA模板的稳定性,导致DNA多态性发生了变化,包括RAPD谱带的增加、缺失及其荧光强度的改变;同时,Cd胁迫抑制了根的伸长生长,促进了根内超氧阴离子( O2-)产生和过氧化氢(H2O2)积累;Cd胁迫下2种植物根的伸长与其根内O2-产生、H2O2积累以及DNA多态性呈负相关,DNA多态性与Cd胁迫下H2 O2积累呈正相关.     

Plasma copeptin in the assessment of febrile neutropenia

Copeptin, the surrogate marker of arginine vasopressin (AVP), has been suggested to be a useful biomarker in monitoring sepsis reflecting hemodynamic imbalance and stress state. This prospective study conducted at a hematology ward in a Finnish University Hospital aimed to investigate whether plasma copeptin predicts the development of complicated course of neutropenic fever (bacteremia or need for treatment at intensive care unit) in 100 hematological patients experiencing their first neutropenic fever episode after intensive chemotherapy for hematological malignancy. Contrary to study presumptions, not elevated copeptin but the lack of a proper initial increase of plasma copeptin (<0.02 ng/mL from day 0 to day 1) predicted blood culture positive sepsis (p=0.023) and gram-negative bacteremia (p=0.045). No correlation was observed with plasma sodium, blood pressure or evaluated osmolality. Plasma copeptin correlated inversely with the same day pentraxin 3 on day 0-day 2 (all p-values <0.001) and with C-reactive protein on day 1 (p=0.015). In conclusion, copeptin did not correlate with disease severity, but the lack of a proper initial increase was associated with bacteremic complications of febrile neutropenia in hematological patients. The findings suggest the possibility of central dysregulation of AVP release and do not support the use of copeptin as a biomarker of septic complications in this patient group.     

Effect of JBP485 on obstructive jaundice is related to regulation of renal Oat1, Oat3 and Mrp2 expression in ANIT-treated rats

Pulmonary vascular endothelial nitric oxide (NO) synthase (eNOS)-derived NO is the major stimulant of cyclic guanosine 5'-monophosphate (cGMP) production and NO/cGMP-dependent vasorelaxation in the pulmonary circulation. We recently synthesized multiple peptides and reported that an eleven amino acid (SSWRRKRKESS) peptide (P1) but not scrambled P1 stimulated the catalytic activity but not expression of eNOS and causes NO/cGMP-dependent sustained vasorelaxation in isolated pulmonary artery (PA) segments and in lung perfusion models. Since cGMP levels can also be elevated by inhibition of phosphodiesterase type 5 (PDE-5), this study was designed to test the hypothesis that P1-mediated vesorelaxation is due to its unique dual action as NO-releasing PDE-5 inhibitor in the pulmonary circulation. Treatment of porcine PA endothelial cells (PAEC) with P1 caused time-dependent increase in intracellular NO release and inhibition of the catalytic activity of cGMP-specific PDE-5 but not PDE-5 protein expression leading to increased levels of cGMP. Acute hypoxia-induced PA vasoconstriction ex vivo and continuous telemetry monitoring of hypoxia (10% oxygen)-induced elevated PA pressure in freely moving rats were significantly restored by administration of P1. Chronic hypoxia (10% oxygen for 4 weeks)-induced alterations in PA perfusion pressure, right ventricular hypertrophy, and vascular remodeling were attenuated by P1 treatment. These results demonstrate the potential therapeutic effects of P1 to prevent and/or arrest the progression of hypoxia-induced PAH via NO/cGMP-dependent modulation of hemodynamic and vascular remodeling in the pulmonary circulation.     

Coupling of permeabilized cells of Gluconobacter oxydans and Ralstonia eutropha for asymmetric ketone reduction using H2 as reductant

A combined two-cell reaction system containing Gluconobacter oxydans and Ralstonia eutropha was evaluated with regard to asymmetric ketone reduction using H₂ as the reductant. Whole cells permeabilized by EDTA/toluene were used, and synthesis was performed in a biphasic aqueous/organic reaction medium. The two-cell system was compared with a system in which G. oxydans alone was used for both ketone reduction and cofactor regeneration, using an alcohol as co-substrate. The two-cell system exhibited almost twice the initial reaction rate of the single-cell system, a higher yield (75% vs. 48%) but slightly lower enantiomeric purity (93% vs. 98%) of the product (S)-2-octanol. The permeabilized R. eutropha cells are worth evaluating for byproduct-free NADH regeneration in combination with other whole cell catalysts.     

Identification of two components of the female sex pheromone of the sugarcane‐borer Diatraea flavipennella (Lepidoptera: Crambidae)

Analysis by gas chromatography with electroantennographic detection of extracts of pheromone glands derived from calling females of the sugarcane‐borer Diatraea flavipennella revealed two antennally active compounds. These components were identified as (Z)‐9‐hexadecenal (Z9–16:Ald) and (Z)‐11‐hexadecenal (Z11–16:Ald) by comparison of the retention times of the natural compounds and the synthetic compounds supported by two‐dimensional gas chromatography – time‐of‐flight mass spectrometric analysis and the positions of the double bounds in the chains were confirmed from the mass spectral fragmentation patterns of their dimethyldisulphide adducts. The analysis indicated that Z9–16:Ald and Z11–16:Ald were present in the sex pheromone in the proportions 25 : 75. Trace amounts of tetradecanal, hexadecanal, (Z)‐7‐hexadecenal (Z7–16:Ald), (Z)‐9‐hexadecen‐1‐ol and (Z)‐11‐hexadecen‐1‐ol were also found in the extract, but of these only Z9–16:Ald and Z11–16:Ald appeared to be antennally active. Behavioural bioassays demonstrated that a binary blend composed of Z9–16:Ald and Z11–16:Ald in the ratio of 25 : 75 induced a response in D. flavipennella virgin males similar to that elicited by live virgin females or by an hexane extract of the pheromone glands of calling females. Z9–16:Ald and Z11–16:Ald are, therefore, considered to be the major constituents of the female sex pheromone of D. flavipennella.     

Complete denture wearing and fractures among edentulous patients treated in university clinics

doi: 10.1111/j.1741‐2358.2011.00551.x
Complete denture wearing and fractures among edentulous patients treated in university clinics Objective: The prevalence of wearing and fracture of complete dentures was evaluated among edentulous patients treated in two dental schools in Brazil. Background: Acceptance and wearing of complete dentures are related to adaptive behaviour of edentulous patients. However, one reason that could interfere with the wearing dentures is their potential to fracture, which is still a common complication in denture rehabilitation practice. Material and methods: Two hundred and twenty‐four edentulous patients rehabilitated with complete dentures from 2000 to 2005 in Araçatuba and Araraquara Dental School, University of State of São Paulo, were assessed in 2006 and 2007 to answer a questionnaire about wearing and fracture of their dentures. Statistical analysis were performed using Epi Info software and chi‐squared test to compare maxillary and mandibular data (α = 0.05). Results: Almost 26% of the patients did not wear their dentures, and among the remainder, the majority wore the maxillary denture. About 30% of the dentures were fractured, with higher prevalence in the maxillary arch (p = 0.003). Conclusions: Discontinuation of wearing dentures was quite high, especially considering the treatment which was carried out in university clinics. Prevalence of fractures was also high, greater for the maxillary denture, and was one of the main reasons for non‐wearing of complete dentures.     

Attitudes and usage of denture adhesives by complete denture wearers: a survey in Greece and the Netherlands

doi: 10.1111/j.1741‐2358.2011.00566.x
Attitudes and usage of denture adhesives by complete denture wearers: a survey in Greece and the Netherlands Objective: To explore whether there are differences in usage of and attitudes towards denture adhesives among patients in two countries. Background: There are no multi‐country surveys concerning usage of and attitudes towards denture adhesives from complete denture wearers. Materials and methods: The survey took place in Greece and the Netherlands with a sample of 284 and 165 consecutive complete denture wearers, respectively, by using a 9‐item prepared questionnaire. Statistical analysis relied on chi‐square test at α = 0.05. Results: In this survey, 26 and 20% of Greek and Dutch patients, respectively, had tried denture adhesive, but only 27% of them in Greece as well as in the Netherlands currently used it; 49% of the Greek and 45% of the Dutch participants rated the overall performance of adhesives as good. Between the two populations, no differences were identified in a majority of the research variables, except where 27% of Greeks answered that they did not know the existence of denture adhesives compared to none of the Dutch patients and when 90% of the Dutch contrary to 70% of Greeks reported that they did not need denture adhesives as they could manage their dentures well. Conclusion: The usage of and attitudes towards denture adhesives between the Greek and Dutch sample were similar with only two exceptions concerning the knowledge of existence and the need of using denture adhesives.