A highly tumor-targeted nanoparticle of podophyllotoxin penetrated tumor core and regressed multidrug resistant tumors

Podophyllotoxin (PPT) exhibited significant activity against P-glycoprotein mediated multidrug resistant (MDR) tumor cell lines; however, due to its poor solubility and high toxicity, PPT cannot be dosed systemically, preventing its clinical use for MDR cancer. We developed a nanoparticle dosage form of PPT by covalently conjugating PPT and polyethylene glycol (PEG) with acetylated carboxymethyl cellulose (CMC-Ac) using one-pot esterification chemistry. The polymer conjugates self-assembled into nanoparticles (NPs) of variable sizes (20–120 nm) depending on the PPT-to-PEG molar ratio (2–20). The conjugate with a low PPT/PEG molar ratio of 2 yielded NPs with a mean diameter of 20 nm and released PPT at ∼5%/day in serum, while conjugates with increased PPT/PEG ratios (5 and 20) produced bigger particles (30 nm and 120 nm respectively) that displayed slower drug release (∼2.5%/day and ∼1%/day respectively). The 20 nm particles exhibited 2- to 5-fold enhanced cell killing potency and 5- to 20-fold increased tumor delivery compared to the larger NPs. The biodistribution of the 20 nm PPT-NPs was highly selective to the tumor with 8-fold higher accumulation than all other examined tissues, while the larger PPT-NPs (30 and 120 nm) exhibited increased liver uptake. Within the tumor, >90% of the 20 nm PPT-NPs penetrated to the hypovascular core, while the larger particles were largely restricted in the hypervascular periphery. The 20 nm PPT-NPs displayed significantly improved efficacy against MDR tumors in mice compared to the larger PPT-NPs, native PPT and the standard taxane chemotherapies, with minimal toxicity.     

Neuraxial blockade in children

Epidural blockade in children has become more popular for postoperative analgesia in recent years owing to increased experience, greater confidence and the development of appropriate equipment. In the UK, approximately 2000 lumbar epidural and continuous caudal blocks are performed each year. Spinal anaesthesia remains popular for babies at risk of postoperative apnoea, but is being superseded by light general anaesthesia with desflurane or sevoflurane combined with caudal blockade. Contraindications to neuraxial blockade include patient or parental refusal, coagulation abnormalities, septicaemia, raised intracranial pressure, meningitis, infection at the entry site, allergy to local anaesthetics, myelomeningocele (spina bifida) and abnormal sacral anatomy for a caudal epidural.     

Directing cell migration using micropatterned and dynamically adhesive polymer brushes

Micropatterning techniques, such as photolithography and microcontact printing, provide robust tools for controlling the adhesive interactions between cells and their extracellular environment. However, the ability to modify these interactions in real time and examine dynamic cellular responses remains a significant challenge. Here we describe a novel strategy to create dynamically adhesive, micropatterned substrates, which afford precise control of cell adhesion and migration over both space and time. Specific functionalization of micropatterned poly(ethylene glycol methacrylate) (POEGMA) brushes with synthetic peptides, containing the integrin-binding arginine–glycine–aspartic acid (RGD) motif, was achieved using thiol–yne coupling reactions. RGD activation of POEGMA brushes promoted fibroblast adhesion, spreading and migration into previously non-adhesive areas, and migration speed could be tuned by adjusting the surface ligand density. We propose that this technique is a robust strategy for creating dynamically adhesive biomaterial surfaces and a useful assay for studying cell migration.     

Uncertainty of antioxidant profiling in complex mixtures using liquid chromatography involving post-column derivatisation

The main goal of this paper is to discuss the problems associated with antioxidant profiling in complex samples using a high-throughput HPLC system coupled with post-column derivatisation reactor. Based on the experimental data reported in the literature, we demonstrated that improper optimisation of temperature and/or pH assay conditions performed using an on-line derivatisation reactor may substantially change the antioxidant peaks ratio of targeted phytochemical compounds. It has been found that despite the relatively high stability of flavonoids at high temperature and under binary mobile phase HPLC conditions, the reaction of target compounds with common ABTS, FCR and DPPH radicals at elevated regions (particularly above 100 °C) dramatically changes their antioxidant activity values expressed, for example, as TEAC (Trolox equivalent antioxidant capacity) parameters. In principle, separation and detection processes of antioxidant profiling assay must not significantly affect the antioxidant activity of target compounds. In the case of foods eaten by humans or animals, critical experimental parameters such as pH and temperature concerning interaction of target analytes with derivatisation reagent should be as close as possible to the real physiological values.     

Novel synthesis of nanosilver particles using plant active principle aloin and evaluation of their cytotoxic effect against Staphylococcus aureus

ObjectiveTo develop a reliable, eco-friendly and easy process for the synthesis of silver nanoparticles using aloin, the active principle of medicinal plant ‘Aloe vera’ and to evaluate antimicrobial activity against Staphylococcus aureus (S. aureus), a causative organism of most of the diseases in livestock and to standardize the level of safety of synthesized silver nanoparticles.MethodsCharacterization using UV-vis spectrophotometry, DLS technique, FT-IR and SEM. Tube dilution method was carried out to evaluate the MIC of the compound against S. aureus. MTT assay was performed to evaluate the level of safety of nanoparticles.ResultsUV-vis absorption spectrum showed a maximum absorption around 200 nm for aloin mediated silver nanoparticles (ANS). The size of the particles as measured by DLS technique was 67.8 nm. The results of FT-IR analysis indicated the involvement of hydroxyl, carboxyl, amine and nitrile groups in the synthesis and stabilization of aloin mediated silver nanoparticles. SEM images showed that ANS with cubical, rectangular, triangular and spherical morphology and measured sizes of the agglomerated nanoparticles are in a range of 287.5 to 293.2 nm, however the average size of an individual particle is estimated to be approximately 70 nm. The compound (ANS) showed a MIC of 21.8 ng/mL against S. aureus and showed an in vitro spleenocyte viability of more than 80% at the highest concentration of 87.5 mg/L per well.ConclusionsAloin consists of functional groups which reduced Ag⁺ ions to Ag° ions and helped in synthesis of silver nanoparticles. The synthesis process has further enhanced the antimicrobial activity of nanosilver. The compound is also proved to be safe at the level many times higher than the MIC.     

Modulación del cambio de isotipo de las inmunoglobulinas por señales del sistema inmunitario innato

Mature B cells emerge from the bone marrow and continue to diversify their immunoglobulin genes through 2 antigen-dependent processes known as somatic hypermutation and class switch recombination. These processes require AID, a DNA-editing enzyme. Although both processes predominantly occur in germinal center B cells engaged in a T cell-dependent (TD) antibody response against protein antigens recent, evidence shows that B cells receive additional help from invariant natural killer T cells, dendritic cells, and various granulocytes, including neutrophils, eosinophils, and basophils. These innate immune cells enhance TD antibody responses by delivering B-cell helper signals whether in germinal centers, postgerminal lymphoid centers, or the bone marrow. In addition to enhancing and complementing the B-cell helper activity of canonical T cells, invariant natural killer T cells, dendritic cells, and granulocytes can deliver T cell-independent B-cell helper signals at the mucosal interface and in the marginal zone of the spleen to initiate rapid innate-like antibody responses. In this review, we discuss recent advances in the role of innate cells in B-cell helper signals and in antibody diversification and production.     

孜然挥发油GC-MS指纹图谱的构建及主成分分析和聚类分析

目的 采用GC-MS指纹图谱并结合多元统计等方法评价不同产地孜然质量。方法 采用气相色谱-四极杆飞行时间质谱（GC-Q-TOF/MS）技术对孜然挥发油进行定性和定量分析，建立20批不同产地孜然的指纹图谱；运用"中药色谱指纹图谱相似度评价系统软件（2012年版）"进行相似度评价，并进行聚类分析和主成分分析。结果 建立的指纹图谱确定了33个共有峰，相似度均>0.961，主要成分包括枯茗醛、γ-松油烯-7-醛、α-松油烯-7-醛、γ-松油烯、o-伞花烃、桧烯、枯茗醇、3-p-孟烯-7-醛等，其相对含量约占总含量的99.7%。通过聚类分析可将20批孜然分为5大类。主成分分析得到4个主成分的累积方差贡献率为88.946%，其结果显示S20号样品综合得分较高。主成分分析与聚类分析结果基本一致。结论 该方法特征性强，仪器精密度、重复性和稳定性良好，可用于孜然挥发油及其相关产品的质量控制和评价。     

Genetic variation within and among species of Cloacina (Strongyloidea: Cloacinine) from the swamp wallaby,Wallabia bicolor (Marsupialia: Macropodidae)

This study examined genetic variation within and among species of Cloacina found in the swamp wallaby (Wallabia bicolor) collected at different localities along the eastern coast of Australia, and evaluated geographical distance as a potential driver for genetic variation. The first and second internal transcribed spacers (ITS-1 and ITS-2, respectively) of the nuclear ribosomal DNA were used to characterize individuals of 11 morphospecies of Cloacina that parasitize W. bicolor. The results of the molecular analyses revealed multiple genotypes for the nine morphospecies of Cloacina (i.e. Cloacina annulata, Cloacina edwardsi, Cloacina eos, Cloacina gallardi, Cloacina mawsonae, Cloacina papillata, Cloacina papillatissima, Cloacina pollux, and Cloacina wallabiae) for which multiple individuals were available for analysis. However, phylogenetic analyses of the sequence data revealed that for each morphospecies, there was no subdivision of individuals into distinct clades based on geographical region from which they were collected. Additional studies are needed to determine the drivers of genetic variation in cloacinid nematodes, and hence increase our understanding of the diversity of parasitic nematodes in macropodid marsupials.     

Synthesis of stable nanosilver particles (AgNPs) by the proteins of seagrass Syringodium isoetifolium and its biomedicinal properties

A simple eco-friendly approach for the hasty synthesis of stable, potent and benign silver nanoparticles (AgNPs) using seagrass, Syringodium isoetifolium was proposed and described here. The UV–Vis, DLS, XRD, AFM, FESEM, EDX and HRTEM analysis highly characterized and confirmed the presence of polydispersed (2–50 nm) spherical and stable AgNPs. FT-IR and phytochemical analysis suggested that the proteins act as reducing and also as capping agent. A hypothetical approach using bioinformatics tools revealed that the Phytochrome B protein of S. isoetifolium might be responsible for the biosynthesis of NPs. Furthermore, biosynthesized AgNPs showed magnificent antibacterial activity against thirteen clinical bacterial pathogens with maximum zone of inhibition of 14.3 ± 0.12 mm due to their smaller size and longer stability even at minimal nanomolar (nM) concentration. In addition, the MIC and MBC values also suggested the same. Moreover, the percentage of haemolysis (8.49 ± 3.10 to 73.34 ± 1.79%) and haemolytic index revealed the satisfactory biocompatibility of AgNPs that showed less/no haemolysis up to 3 nM concentration. Further, the toxicity effect of biosynthesized AgNPs against the brine shrimp, Artemia salina exhibited significantly increasing mortality (13 ± 4.7 to 100%) with LC₅₀ value at 4 nM concentration. Thus, the optical property, crystal structure, size, shape, stability, bactericidal activity, cytotoxicity, and biocompatibility apparently proved that the biologically synthesized AgNPs have typical properties of nanomaterials.