Calendering as a direct shaping tool for the continuous production of fixed-dose combination products via co-extrusion

In this study calendering is used as a downstream technique to shape monolithic co-extruded fixed-dose combination products in a continuous way. Co-extrudates with a metoprolol tartrate-loaded sustained-release core and a hydrochlorothiazide-loaded immediate-release coat were produced and immediately shaped into a monolithic drug delivery system via calendering, using chilled rolls with tablet-shaped cavities. In vitro metoprolol tartrate release from the ethylcellulose core of the calendered tablets was prolonged in comparison with the sustained release of a multiparticulate dosage form, prepared manually by cutting co-extrudates into mini-matrices. Analysis of the dosage forms using X-ray micro-computed tomography only detected small differences between the pore structure of the core of the calendered tablet and the mini-matrices. Diffusion path length was shown to be the main mechanism behind the release kinetics. Terahertz pulsed imaging visualized that adhesion between the core and coat of the calendered tablet was not complete and a gradient in coat thickness (varying from 200 to 600 μm) was observed. Modulated differential scanning calorimetry and X-ray diffraction indicated that the solid-state properties of both drugs were not affected by the calendering procedure.     

基于紫外光谱和偏最小二乘回归算法的畲药地稔中浸出物和6种活性成分快速预测方法

目的 建立基于紫外光谱的畲药地稔中浸出物、没食子酸、阿魏酸、芦丁、槲皮素、木犀草素、山奈酚的快速分析方法。方法 测定地稔水提液中的浸出物和6种化合物浓度,采集紫外光谱。采用SIMCA-P+软件,分别建立浸出物、6种化合物浓度与紫外光谱的偏最小二乘回归模型。采用Visual Basic开发应用软件,将所建模型嵌套入软件,为同时快速分析待测溶液中浸出物和6种化合物浓度提供工具。结果 验证集浸出物和6种化合物浓度的预测均方根误差分别为39.1 μg/mL、0.263 μg/mL、19.0 ng/mL、93.8 ng/mL、0.894 ng/mL、0.593 ng/mL、0.896 ng/mL,预测值和真实值的相关系数均>0.9,并通过软件在10 s内得到了浸出物和6种化合物浓度的预测结果。结论 本方法可为地稔的快速质量评价提供依据。     

雌二醇及中波紫外线在豚鼠皮肤色素沉着形成中的作用及其机制

目的：研究雌二醇和中波紫外线( UVB)辐射对豚鼠背部棕色皮肤中黑素代谢的影响,探讨雌激素及UVB在皮肤色素沉着中的作用。方法选取健康花色豚鼠,设立溶媒对照组、UVB照射组、雌二醇处理组和雌二醇预处理后UVB照射组(雌二醇+UVB组);雌二醇浓度设为3．67×10-5、3．67×10-4、3．67×10-3 mol/L;UVB 照射剂量统一为500 mJ/cm2。采用皮肤在体共聚焦激光扫描显微镜(简称皮肤CT)以及透射电子显微镜等观察雌二醇和UVB对黑素小体合成及降解的影响。结果①一定浓度雌二醇可加深豚鼠皮肤色素沉着,且随着雌二醇浓度的递增,沉着程度逐渐加深(P<0．05)。② UVB照射组豚鼠皮肤色素沉着较未照射组明显增加(P<0．05)。③ UVB照射后豚鼠表皮角质形成细胞中自噬体增加,而雌二醇处理后自噬体减少。结论雌二醇及UVB照射均可促进豚鼠皮肤色素沉着,其机制可能与促进黑素小体合成有关,黑素小体的降解异常也参与了豚鼠皮肤色素沉着的形成。     

Resistance to Ultraviolet Aging of Nano-SiO2 and Rubber Powder Compound Modified Asphalt

Ultraviolet (UV) aging degrades the life span of asphalt pavement, nanomaterials used as modifiers exhibit good shielding function on UV light, but generally degrade the low-temperature property of asphalt, a compound modification was found to be a solution. In this study, nano-SiO₂ and rubber powder were blended together with base asphalt to prepare compound modified asphalt. Compound modified asphalt with different blending dosages were subjected to UV light via a self-made UV aging simulation chamber. Basic performance tests and rheological tests were conducted including the UV aging influence. An optimum compound ratio was finally recommended based on the goal to remove the adverse effect of nano-SiO₂ on the thermal cracking. Results show that the anti-UV aging property of asphalt is improved obviously due to the blocking function of nano-SiO₂ and carbon black in rubber powder, and the enhancing effect of nano-SiO₂ is found to be the most significant.     

虾青素/天然DNA/壳聚糖纳米粒对紫外诱导的小鼠皮肤光老化的改善作用

目的 探究虾青素/天然DNA/壳聚糖纳米粒（Ast/DC）对紫外诱导的小鼠皮肤光老化的改善作用。方法 分子自组装结合溶剂蒸发法制备Ast/DC。紫外照射脱毛小鼠30 d模拟皮肤光老化,研究Ast/DC对小鼠皮肤表观形态、组织纤维结构以及皮肤中超氧化物歧化酶（SOD）等抗氧化因子表达水平等的影响;并用Franz扩散池模拟透皮吸收过程研究纳米载体对虾青素的经皮递送效果。结果 将平均粒径为266 nm、Zeta电位为32.7 mV的Ast/DC（虾青素有效剂量为1.5 μg?cm-2?d-1）涂抹于紫外照射小鼠的背部,可维持其皮肤正常形态和结构,在角质层厚度、胶原纤维和弹性纤维结构等方面与未经紫外照射小鼠相比无明显差异;并且皮肤组织中的谷胱甘肽（GSH）、SOD和过氧化氢酶（CAT）表达水平较光老化小鼠分别显著提高31.4%、25.1%和41.7%（P＜0.05）。当虾青素有效涂抹剂量低至0.33 μg?cm-2?d-1时,Ast/DC仍能显著提高皮肤组织中的抗氧化因子表达水平,且优于游离虾青素;相较于光老化模型小鼠,低剂量Ast/DC组小鼠和虾青素油（Ast/oil）组小鼠中GSH含量分别提高26.4%和15.1%。同时,Ast/DC的24 h累积透皮吸收量比游离虾青素提高20.7%。结论Ast/DC能有效保护小鼠皮肤,抵御紫外照射引起的皮肤光老化。     

Amino acid addition to Vibrio cholerae LPS establishes a link between surface remodeling in gram-positive and gram-negative bacteria

Historically, the O1 El Tor and classical biotypes of Vibrio cholerae have been differentiated by their resistance to the antimicrobial peptide polymyxin B. However, the molecular mechanisms associated with this phenotypic distinction have remained a mystery for 50 y. Both gram-negative and gram-positive bacteria modify their cell wall components with amine-containing substituents to reduce the net negative charge of the bacterial surface, thereby promoting cationic antimicrobial peptide resistance. In the present study, we demonstrate that V. cholerae modify the lipid A anchor of LPS with glycine and diglycine residues. This previously uncharacterized lipid A modification confers polymyxin resistance in V. cholerae El Tor, requiring three V. cholerae proteins: Vc1577 (AlmG), Vc1578 (AlmF), and Vc1579 (AlmE). Interestingly, the protein machinery required for glycine addition is reminiscent of the gram-positive system responsible for D-alanylation of teichoic acids. Such machinery was not thought to be used by gram-negative organisms. V. cholerae O1 El Tor mutants lacking genes involved in transferring glycine to LPS showed a 100-fold increase in sensitivity to polymyxin B. This work reveals a unique lipid A modification and demonstrates a charge-based remodeling strategy shared between gram-positive and gram-negative organisms.     

Bax抑制因子1对紫外线B诱导下人晶状体上皮细胞凋亡的抑制作用

目的　探讨Bax抑制因子1（BI-1）对紫外线B（UVB）诱导下人晶状体上皮细胞凋亡的抑制作用。方法　取对数生长期的人晶状体上皮细胞（HLEC）系SRA01/04细胞,将BI-1过表达质粒及其空载质粒转染至SRA01/04细胞中,分别记为BI-1组、Vector组,另取不做任何处理的SRA01/04细胞作为blank组。转染48 h后,采用实时荧光定量PCR和Western blot检测转染后各组细胞中BI-1 mRNA和蛋白表达水平。而后再根据实验需要将细胞分为6组:（1）Control组,SRA01/04细胞不经任何处理;（2）UVB组,采用紫外线（2.0 W·cm^-2）处理SRA01/04细胞60 min;（3）Vector组,转染BI-1空载质粒的SRA01/04细胞;（4）BI-1组,转染BI-1过表达质粒的SRA01/04细胞;（5）Vector+UVB组,转染BI-1空载质粒的SRA01/04细胞,再经紫外线（2.0 W·cm^-2）照射60 min;（6）BI-1+UVB组,转染BI-1过表达质粒的SRA01/04细胞,再经紫外线（2.0 W·cm^-2）照射60 min。采用实时荧光定量PCR检测UVB照射后各组细胞中BI-1 mRNA表达水平,CCK-8法检测细胞增殖情况,流式细胞仪检测各组细胞中活性氧（ROS）含量,荧光探针法检测细胞内质网内Ca²⁺浓度,流式细胞仪检测细胞凋亡率,Western blot检测各组细胞中相关蛋白表达水平。结果　本研究中所培养的SRA01/04细胞在荧光显微镜下可观察到细胞内αA-晶状体蛋白呈红色荧光。随着UVB照射强度增加,SRA01/04细胞内BI-1 mRNA表达水平逐渐降低,本研究选择UVB照射强度为2.0 W·cm^-2进行后续的实验。与blank组或Vector组相比,BI-1组细胞中BI-1 mRNA和蛋白表达水平均显著上升,差异均有统计学意义（均为P＜0.05）。与Control组比较,UVB组细胞增殖活性显著降低,细胞内ROS含量显著增加,细胞内质网内Ca²⁺浓度显著升高,细胞凋亡率显著升高,细胞内Cleaved-caspase-3、Bax蛋白表达水平显著上调,Bcl-2蛋白表达水平显著下调,细胞内GRP78、p-IRE1、p-JNK和Cleaved-caspase-12蛋白表达水平显著上调（均为P＜0.05）。BI-1+UVB组细胞增殖活性较UVB组显著增高,细胞内ROS含量较UVB组显著降低,细胞内质网内Ca²⁺浓度较UVB组显著下降;与UVB组比较,BI-1+UVB组细胞凋亡率显著下降,细胞内Cleaved-caspase-3、Bax蛋白表达水平显著下调,Bcl-2蛋白表达水平显著上调;BI-1+UVB组细胞内GRP78、p-IRE1、p-JNK和Cleaved-caspase-12蛋白表达水平较UVB组显著下调（均为P＜0.05）。结论　BI-1在UVB诱导的HLEC系SRA01/04细胞中表达显著下调,BI-1过表达可通过降低内质网内Ca²⁺浓度抑制内质网应激介导的IRE1-JNK信号通路的激活,进而抑制UVB诱导的SRA01/04细胞凋亡。