家兔各组织蛋白二硫键异构酶的活性及含量研究

目的　探讨蛋白二硫键异构酶 (PDI)的生物学功能及与微粒体的关系。方法　应用改良的Hill son方法及酶联免疫技术 ,测定家兔不同组织细胞内PDI的活性及其含量。结果　家兔不同组织细胞内均有PDI分布 ,但酶活性及含量差异显著 ,在分泌功能旺盛的胰腺细胞、肝细胞其含量占细胞总蛋白的 2～ 6 % ,是肌细胞的 10 0倍 ,酶比活性为 4～ 2 4unit/g ,约为肌细胞的 80～ 40 0倍 ,不同细胞微粒体获得率明显不同 ,单位重量微粒体蛋白含量基本相同。结论　不同细胞内质网含量不同 ,而单位重量内质网的蛋白种类和含量具有一定保守性     

湖北省1991～2001年5岁以下儿童死亡监测结果分析

目的分析湖北省5岁以下儿童死亡率的变化趋势和潜在寿命损失年数,评价干预措施的效果.方法采用线形回归模型分析5岁以下儿童死亡率的变化趋势,并利用5岁以下儿童死亡率指数、婴儿死亡率指数和可预防性指数评价干预措施的效果.结果湖北省2001年5岁以下儿童死亡率为28.37‰,婴儿死亡率为23.24‰,与1991年相比具有明显的下降趋势.主要死因分别为肺炎、出生窒息、早产低出生体重和意外窒息.5岁以下儿童和婴儿潜在寿命损失率(PYLL‰)分别为190.34年/千人和1731.22年/千人.可预防性指数在1991年的基础上分别下降15和13位次.结论5岁以下儿童主要死因是潜在寿命损失的最主要原因,必须大力开展儿童死亡的监测与干预工作.     

Lineage-related and particle size-dependent cytotoxicity of chitosan nanoparticles on mouse bone marrow-derived hematopoietic stem and progenitor cells

Chitosan nanoparticles (CSNPs) have potential applications in stem cell research. In this study, ex vivo cytotoxicity of CSNPs on mouse bone marrow-derived (MBMCs) hematopoietic stem and progenitor cells (HSPCs) was determined. MBMCs were exposed to CSNPs of different particle sizes at various concentrations for up to 72 h. Cytotoxicity effect of CSNPs on MBMCs was determined using MTT, Live/Dead Viability/Cytotoxicity assays and flow cytometry analysis of surface antigens on HSCs (Sca-1⁺), myeloid-committed progenitors (CD11b⁺, Gr-1⁺), and lymphoid-committed progenitors (CD45⁺, CD3e⁺). At 24 h incubation, MBMCs' viability was not affected by CSNPs. At 48 and 72 h, significant reduction was detected at higher CSNPs concentrations. Small CSNPs (200 nm) significantly reduced MBMCs' viability while medium-sized particle (∼400 nm) selectively promoted MBMCs growth. Surface antigen assessment demonstrated lineage-dependent effect. Significant decrease in Sca-1⁺ cells percentage was observed for medium-sized particle at the lowest CSNPs concentration. Meanwhile, reduction of CD11b⁺ and Gr-1⁺ cells percentage was detected at high and intermediate concentrations of medium-sized and large CSNPs. Percentage of CD45⁺ and CD3e⁺ cells along with ROS levels were not significantly affected by CSNPs. In conclusion, medium-sized and large CSNPs were relatively non-toxic at lower concentrations. However, further investigations are necessary for therapeutic applications.     

Mitomycin‐C: ‘a ray of hope’ in refractory corrosive esophageal strictures

Increasingly frequent dilation may become a self‐defeating cycle in refractory stricture as recurrent trauma enhance, scar formation, and ultimately recurrence and potential worsening of the stricture. In 12 patients of caustic induced esophageal stricture, who failed to respond despite rigorous dilatation regimen for more than one year, a trial of topical mitomycin‐C application to improve dilatation results was undertaken, considering the recently reported efficacy and safety of this agent. Mitomycin‐C was applied for 2–3 minutes at the strictured esophageal segment after dilation with wire‐guided Savary‐Gilliard dilator. Patient was kept nil by mouth for 2–3 hours. After 4–6 sessions of mitomycin‐C treatment, resolution of symptoms and significant improvement in dysphagia score and periodic dilatation index was seen in all 12 patients. Mitomycin‐C topical application may be a useful strategy in refractory corrosive esophageal strictures and salvage patients from surgery.     

Photodynamic therapy effect on cell growth inhibition induced by Radachlorin and toluidine blue O on Staphylococcus aureus and Escherichia coli: An in vitro study

IntroductionPhotodynamic therapy is an innovative treatment modality, which is appropriate for tumor detection and for the treatment of cancer as well as nontumoral diseases, such as psoriasis (2), bacterial and viral eradication.Material and methodEffect of two photosensitizer (toluidine blue O (TBO) and Radachlorin was investigated on Staphylococcus Aureus ATCC 25923 (American Type Culture Collection) and Escherichia coli (ATCC 25922).ResultsPDI by TBO caused S. aureus 5.83 log10 killing (P.Value < 0.0001) and reduce 0.08 log 10 in E. coli (P.Value = 0.321). PDI by Radachlorin^® reduce 0.17 log 10 in E. coli (P.Value < 0.0001) and S. aureus showed 6.1 log 10 colony count reduction.ConclusionWithin the limitation of this in vitro study, we can conclude that both PS have the same effect on S. aureus and E. coli with good inhibition effect on S. aureus and partial inhibition effect E. coli.     

Dibucaine in Ionic-Gradient Liposomes: Biophysical,Toxicological, and Activity Characterization

Administration of local anesthetics is one of the most effective pain control techniques for postoperative analgesia. However, anesthetic agents easily diffuse into the injection site, limiting the time of anesthesia. One approach to prolong analgesia is to entrap local anesthetic agents in nanostructured carriers (e.g., liposomes). Here, we report that using an ammonium sulphate gradient was the best strategy to improve the encapsulation (62.6%) of dibucaine (DBC) into liposomes. Light scattering and nanotracking analyses were used to characterize vesicle properties, such as, size, polydispersity, zeta potentials, and number. In vitro kinetic experiments revealed the sustained release of DBC (50% in 7 h) from the liposomes. In addition, in vitro (3T3 cells in culture) and in vivo (zebrafish) toxicity assays revealed that ionic-gradient liposomes were able to reduce DBC cyto/cardiotoxicity and morphological changes in zebrafish larvae. Moreover, the anesthesia time attained after infiltrative administration in mice was longer with encapsulated DBC (27 h) than that with free DBC (11 h), at 320 μM (0.012%), confirming it as a promising long-acting liposome formulation for parenteral drug administration of DBC.     

Nanoformulations of anticancer FGFR inhibitors with improved therapeutic index

Fibroblast growth factor receptor (FGFR) inhibitors like ponatinib and nintedanib are clinically approved for defined cancer patient cohorts but often exert dose-limiting adverse effects. Hence, we encapsulated the FGFR inhibitors ponatinib, PD173074, and nintedanib into polylactic acid nanoparticles and liposomes to enable increased tumor accumulation/specificity and reduce side effects. Different methods of drug loading were tested and the resulting formulations compared regarding average size distribution as well as encapsulation efficiency. Appropriate encapsulation levels were achieved for liposomal preparations only. Nanoencapsulation resulted in significantly decelerated uptake kinetics in vitro with clearly decreased short-term (up to 72?h) cytotoxicity at higher concentrations. However, in long-term clonogenic assays liposomal formations were equally or even more active as compared to the free drugs. Accordingly, in an FGFR inhibitor-sensitive murine osteosarcoma transplantation model (K7M2), only liposomal but not free ponatinib resulted in significant tumor growth inhibition (by 60.4%) at markedly reduced side effects.     

Time Interval of Two Injections and First-Dose Dependent of Accelerated Blood Clearance Phenomenon Induced by PEGylated Liposomal Gambogenic Acid: The Contribution of PEG-Specific IgM

Repeated injection of PEGylated liposomes can cause the disappearance of long circulating property because of the induction of anti-PEG IgM antibody referred to as “accelerated blood clearance (ABC) phenomenon.” Although ABC phenomenon typically occurs when entrapped drugs are chemotherapeutic agent with low cytotoxic, there is little evidence of accelerated blood clearance of PEGylated herbal-derived compound on repeated injection. Herein, we investigated the blood concentration of PEGylated liposomal gambogenic acid (PEG-GEA-L), a model PEGylated liposomal herbal extract, on its repeated injection to rats. We found time interval between injections had considerable impact on the magnitude of ABC phenomenon induced by PEG-GEA-L. When time interval was prolonged from 3 days to 7 days, ABC phenomenon could be attenuated. Furthermore, its magnitude was enhanced accompanied by a marked rise in the accumulation of PEG-GEA-L in the liver and spleen in a first-dose–dependent manner. Consistently, the level of anti-PEG IgM significantly increased with the first dose of PEG-GEA-L and decreased with the extended time interval between injections, which implies anti-PEG IgM is a major contributor to the ABC phenomenon. Notably, the increased expression of liver anti-PEG IgM was accompanied by an increased expression of efflux transporters in the induction process of the ABC phenomenon.     

Codelivery of Adriamycin and P-gp Inhibitor Quercetin Using PEGylated Liposomes to Overcome Cancer Drug Resistance

Transmembrane protein P-gp's overexpression at the drug-resistant cell membrane is the most important characteristic of multidrug resistance (MDR). Quercetin (QUE) can effectively suppress the function of P-gp to reverse MDR. This study uses QUE as the P-gp inhibitor andfilm-ultrasound technique with ammonium sulfate transmembrane gradient method to prepare long-circulating liposomes simultaneously encapsulating QUE and Adriamycin (doxorubicin) (AMD/DOX). The optimal conditions for the preparation of AMD_QUE_long-circulating liposomes (SLs) are as follows: hydrogenated soybean phospholipids (HSPC):cholesterol:DSPE-PEG 2000 = 73.07:24.36:2.57 mol/mol, QUE:HSPC = 1:20 mol/mol, AMD:HSPC = 1:7.9 w/w (NH₄₎₂SO₄ 0.15 mol/L, drug loaded (AMD) at 55°C for 25 min). The average encapsulation efficiency of AMD and QUE was 97.49% and 95.50%, respectively. The average particle size is 85 nm (n = 3), and the average zeta potential is ?14.9 mV. First, the pharmacokinetic study proved that codelivery liposomes enveloping QUE and AMD (AMD_QUE_SL) can obviously increase the blood concentration of AMD (C_max: 140.50 ± 32.37 μg/mL) and extend the half-life period of AMD in plasma (t_1/2:14.02 ± 1.54 h). Second, AMD_QUE_SL can obviously enhance the cell toxicity to AMD-resistant cell strains (HL-6/ADR and MCF-7/ADR), and the reverse effects on the resistance of HL-6/ADR and MCF-7/ADR is increased to 4.81-fold and 3.21-fold, respectively. Third, according to the in vivo pharmacodynamic study, the relative tumor volume and relative tumor growth of the AMD_QUE_SL group were the lowest. The inhibition rate of tumor growth of this group was the highest. It can be concluded that AMD_QUE_SL can effectively reverse MDR, lower cardiac toxicity of AMD in clinical treatment, and improve the clinical treatment effect of AMD.     

A Nonionic Polyethylene Oxide (PEO) Surfactant Model: Experimental and Molecular Dynamics Studies of Kolliphor EL

Polyethoxylated, nonionic surfactants are important constituents of many drug formulations, including lipid-based formulations. In an effort to better understand the behavior of formulation excipients at the molecular level, we have developed molecular dynamics (MD) models for the widely used surfactant Kolliphor EL (KOL), a triricinoleate ester of ethoxylated glycerol. In this work, we have developed models based on a single, representative molecular component modeled with 2 force field variations based on the GROMOS 53A6_DBW and 2016H66 force field parameters for polyethoxylate chains. To compare the computational models to experimental measurements, we investigated the phase behavior of KOL using nephelometry, dynamic light scattering, cross-polarized microscopy, small-angle X-ray scattering, and cryogenic transmission electron microscopy. The potential for digestion of KOL was also evaluated using an in vitro digestion experiment. We found that the size and spherical morphology of the KOL colloids at low concentrations was reproduced by the MD models as well as the growing interactions between the aggregates to from rod-like structures at high concentrations. We believe that this model reproduces the phase behavior of KOL relevant to drug absorption and that it can be used in whole formulation simulations to accelerate the formulation development.