Non-cytotoxic silver nanoparticle-polyvinyl alcohol hydrogels with anti-biofilm activity: designed as coatings for endotracheal tube materials

Endotracheal intubation is commonly associated with hospital-acquired infections as the intubation device acts as reservoir for bacterial colonization in the lungs. To reduce the incidence of bacterial colonization on the tubes, hydrogel coatings loaded with antimicrobial agents are gaining popularity. The aim of this study was to incorporate silver nanoparticles (AgNPs) into polyvinyl alcohol (PVA) to form stable hydrogels. Embedding AgNPs into PVA resulted in a decreased elongation at break and an increased tensile strength compared to PVA alone. The Ag release profile varied as a function of the degree of hydrolysis of PVA: the higher degree of hydrolysis demonstrated a lower release rate. Fourier infrared transform spectroscopy demonstrated that AgNPs interacted exclusively with the –OH groups of PVA. AgNP-loaded PVA was non-toxic against human normal bronchial epithelial cells while effective against the attachment of Pseudomonas aeruginosa and Staphylococcus aureus with a greater effect on P. aeruginosa.     

Synergistic anti-biofouling effect of Ag-exchanged zeolite and D-Tyrosine on PVC composite against the clinical isolate of Acinetobacter baumannii

Due to their susceptibility to bacterial biofilm formation, commercial tubes for medical use are one of the main sources of hospital infections with Acinetobacter baumannii. The anti-biofouling activity of novel composites against the clinical isolate of the multi-drug resistant A. baumannii is reported here. The composites were prepared by addition of micronised silver-exchanged natural zeolite (Ag-NZ) into poly(vinyl chloride) (PVC), followed by coating of the composites with D-Tyrosine (D-Tyr). The Ag-NZ composites (containing 1–15 wt% of Ag-NZ) coated with D-Tyr (Ag-NZ-Tyr) showed a bactericidal effect (100% or a 6.9 log CFU reduction) towards immobilised bacterial cells. The uncoated Ag-NZ composites showed a reduction of up to 70% (4.4 log CFU) of immobilised bacteria in comparison with the original PVC. Rheological testing of the composites revealed that the addition of Ag-NZ slightly affected processability and formability of the PVC and increased the elasticity of the polymer matrix.     

Discovery of N-(3-((7H-purin-6-yl)thio)-4-hydroxynaphthalen-1-yl)-sulfonamide derivatives as novel protein kinase and angiogenesis inhibitors for the treatment of cancer: Synthesis and biological evaluation. Part III

A novel series of N-(3-((7H-purin-6-yl)thio)-4-hydroxynaphthalen-1-yl)-sulfonamides were designed and synthesized. Biological characterization revealed that several compounds exerted enhanced anti-proliferative activity against human umbilical vein endothelial cells (HUVECs) and several cancer cell lines and high specific protein kinase and angiogenesis inhibitory activities. Compared with our previously synthesized compounds, the substitution of sulfonamide structure for amide fragment played an essential role for the advance of inhibitory activities. In addition, the replacement of 1H-1,2,4-triazole ring by 7H-purine did not result in obvious decrease of inhibition efficacy, indicating that the sulfonamide structure contributes even more to the inhibition efficacy than the 1H-1,2,4-triazole ring. Among these compounds, compound 9n demonstrated comparable in vitro antiangiogenic activities to pazopanib in both HUVEC tube formation assay and the rat thoracic aorta rings (TARs) test. Meanwhile, compound 9n was identified to inhibit Akt1 (IC₅₀ = 1.73 μM) and Abl tyrosine kinase (IC₅₀ = 1.53 μM) effectively.     

枇杷少核株系花粉管生长差异研究

以‘大五星’枇杷退化种子少核株系‘川农1号’(C1)为试材,以‘大五星’枇杷自花授粉为对照,采用荧光显微技术,对枇杷少核株系自花、异花授粉后花粉管生长情况进行观察。结果表明:(1)C1株系异花授粉后花粉能在柱头上萌发,并伸入中央花柱道,在授粉后48h左右到达花柱基部。(2)C1株系自花授粉后,花粉萌发与花粉管的伸长速度相对于异花授粉滞后,自花授粉后36h大多数花粉管到达花柱的中上部并停止生长,且伴随产生花粉管顶端形态异常、荧光异常明亮等现象,最终只有极少数花粉管能到达花柱基部。研究表明,C1株系为配子体自交不亲和,C1株系的自交不亲和性是引起其少核的重要原因之一。     

低剂量胸部CT自动管电流调节技术在超重体型患者检查中的可行性研究

目的：探讨16层螺旋CT自动管电流调节技术（CAREDose4D）在超重体型患者检查中的可行性。方法：收集行胸部CT检查的超重体型患者（BMI值于24-27．9之间）100例,扫描分低剂量组（A组）和常规剂量组（B组）,其中A组扫描运用CAREDose4D技术自动调节管电流;B组扫描运用常规剂量管电流为70mAs扫描。扫描完成后记录加权CT剂量指数（CTDlvol）、有效mAs值、剂量长度乘积（DLP）,计算出有效剂量（ED）及剂量减低比值（DR）,并比较两组的剂量及图像质量。结果：与B组相比,A组常规扫描辐射剂量显著降低,差异有显著统计学意义（P〈0．01）,A组剂量减低比值（DR）降低约20．84％,而图像质量无明显下降,不影响诊断,在主动脉弓上4cm（肺尖）层面A组图像质量优于B组,差异有统计学意义（x^2=8．442,P=0．015）。结论：自动管电流调节技术既可以减少患者的辐射剂量,对待超重体型患者个体化、人性化,又不影响影像诊断,是一项有价值的检查方法。     

甲氨蝶呤对早期神经胚基因表达的影响

目的:利用甲氨蝶呤(methotrexate,MTX)干预孕鼠,探讨MTX对早期神经胚基因表达的影响。方法:用MTX(4.5 mg/kg体重)干预孕鼠,通过NimbleGene表达谱芯片、Real time-PCR及免疫组化等方法进行差异表达基因的筛选和验证。结果:MTX处理后神经管畸形(NTDs)发生率为32.1%。表达谱芯片筛选出166个差异表达基因,其中4个凋亡相关基因(Endog,Trp53,Casp3,Bax)均表现为上调(fold change1.5,P0.05),3个增殖相关基因(Ptch1,Pla2g4a,Foxg1)均表现为下调(fold change0.67,P0.05);NTDs胚胎神经上皮Caspase-3表达显著升高(P0.05),phospho-histone H3(pH3)表达显著降低(P0.05)。结论:MTX影响了早期神经胚的基因表达,尤其是引起了凋亡、增殖相关基因表达的异常,这可能在叶酸缺乏引起NTDs发生的相关机制之一。     

长期留置管细菌分布及生物膜形成能力调查

目的了解长期留置管细菌分布及生物膜形成能力。方法10％血清肉汤振荡培养留置管中细菌,常规生化和分子生物学方法鉴定分离菌,结晶紫半定量法检测分离菌生物膜形成能力。结果留置管细菌检出率为49．1％（53／108）;共分离60株菌,以葡萄球菌分离率最高（70．0％）,其次为肠球菌（15．O％）和大肠埃希菌（6．7％）;所有分离菌均具有生物膜形成能力,其中38株（63．3％）具有较强的生物膜形成能力。结论长期留置管细菌检出率较高,大部分分离菌具有较强的生物膜形成能力。     

不同浓度卡那霉素、潮霉素对楸树试管苗生长的影响

目的:将不同质量浓度的卡那霉素、潮霉素加入楸树培养基中,研究卡那霉素、潮霉素对楸树组培苗生长的影响,以确定抗生素对楸树茎段分化与生根的敏感质量浓度。方法:待楸树继代、生根培养基灭菌后温度降至30~50℃,将不同质量浓度的卡那霉素、潮霉素经抽滤式灭菌加入培养基中,在培养基中接入楸树组培无菌茎段培养,观测茎段继代(增殖芽数、芽长、叶数等)、生根(发根数、根长、芽长等)生长指标并统计分析。结果:楸树组培继代培养基添加卡那霉素质量浓度为100 mg/L时组培瓶苗生长缓慢,浓度为150 mg/L时叶片大部分发白并干枯,茎段基部无愈伤组织形成,瓶苗基本停止生长,楸树继代瓶苗对卡那霉素耐受性范围为100~150 mg/L;添加潮霉素质量浓度为5 mg/L时瓶苗生长较为缓慢,浓度为10 mg/L时叶片开始干枯,茎段基部愈伤组织较小,瓶苗基本停止生长,楸树继代瓶苗对潮霉素耐受性范围为10 mg/L左右。楸树组培生根培养基添加卡那霉素质量浓度为100 mg/L时大部分茎段干枯,少部分为绿但未分化芽与根,浓度为150 mg/L时大部分茎段干枯,极少上部为绿,基部干枯,但未分化芽与根,楸树组培瓶苗生根培养苗对卡那霉素耐受性范围为100~150 mg/L;添加潮霉素质量浓度为5 mg/L时少部分茎段干枯,浓度为10 mg/L时大部分茎段干枯,少部分为绿,茎段未出现芽的分化与根的萌发现象,楸树组培瓶苗生根培养苗对潮霉素耐受性范围为5~10 mg/L。结论:卡那霉素、潮霉素对楸树组培苗生长有明显的抑制作用且与抗生素浓度呈负相关,但低质量浓度(1 mg/L)的潮霉素对楸树继代分化芽数有促进作用;同一抗生素对楸树不同无性系间组培苗生长的影响无显著差异。     

A cadaver unearthed: the anatomy of the Japanese living fossil Stirpulina ramosa (Bivalvia: Anomalodesmata: Clavagellidae) – the unique specimen in the collections of Emperor Shōwa

The only extant, preserved and complete specimen of Stirpulina ramosa has been discovered in the collections of the late Emperor Shōwa (Hirohito) and is described herein. Hitherto, only shells and the adventitious tubes of this species have been described. This study of the anatomy complements previous ones and adds further information as to how the adventitious tube is formed: that is, by the laying down of an organic, periostracum‐like, template that is then biomineralized internally to form the tube and is externally plastered with the clasts that constitute the enclosing burrow wall. Such secretions are produced by pallial lobes that unite on the right side to create the characteristic sutured pleat in this region of the tube. The periostracum enclosing the so‐interred animal is then secreted against the internal template of the tube. The shell of S. ramosa and, as a consequence, the musculature, is greatly disfigured as a result of the incorporation of the left valve into the fabric of the adventitious tube. This valve can, however, continue to grow within the tube, especially posteriorly. The right valve remains free inside the tube but grows only a little more anteriorly. The anterior mantle, with a minute pedal gape, is greatly thickened and secretes the watering pot component of the tube. In many anatomical respects, for example simultaneous hermaphroditism, S. ramosa still reflects the basic anomalodesmatan plan and such modifications as there are from the clavagellid form relate principally to the structure, formation and thus functioning of the adventitious tube. This study of S. ramosa has allowed the full spectrum of clavagellid adaptive radiation to be analysed and an evolutionary picture created which suggests that species of Clavagella/Dacosta and Stirpulina are Mesozoic (Late Cretaceous) remnants. Conversely, species of Bryopa and Dianadema are more modern, Late Oligocene and Palaeocene (Cenozoic), respectively, and possibly evolved in association with the emergence of the Indo‐West Pacific centre of coral diversity, with a postulated average age of just 30 Myr. © 2013 The Linnean Society of London