龙葵碱对人结肠癌鸡胚移植模型血管生成的影响

目的：建立人结肠癌鸡胚移植模型,研究龙葵碱对其血管生成的影响。方法将鸡胚分为对照组和低剂量组、中剂量组、高剂量组（均n＝10）,将培养的人结肠癌细胞系HT‐29细胞株接种到鸡胚绒毛尿囊膜（CAM）上,通过立体显微镜、Image‐proplus6．0图像分析软件及免疫组织化学苏木精‐伊红（HE）染色法,观察移植瘤在CAM上血管生成的特点,及不同龙葵碱剂量对血管生成的影响。结果HT‐29细胞接种到CAM第3～5天,大量血管向瘤体集中,长入或跨越瘤体表面,肿瘤迅速生长。给药后第5天进行拍照,图像分析,定量计算血管新生面积明显低于对照组,且呈剂量依赖性,各组间差异有统计学意义（P＜0．01）。免疫组织化学检测表明不同剂量龙葵碱的微血管密度明显低于对照组,与血管新生面积相一致;ki‐67抗原表达指数逐渐下降,实验组低于对照组,且各组间差异有统计学意义（P＜0．01）。结论龙葵碱能明显抑制人结肠癌HT‐29细胞株诱导的血管生成,从而抑制肿瘤的生长,为抗肿瘤血管生成的治疗方面提供了重要依据。     

康柏西普治疗老年性黄斑变性的研究现状

老年性黄斑变性( AMD)已经成为发达国家老年人致盲的主要原因之一。随着AMD患者的逐年增加,这也成为眼科防盲研究中重要的课题之一。其病因并不完全清楚,但许多研究表明血管内皮生长因子( VEGF)在其发病中起了重要作用。随着抗VEGF药物的研发与应用,目前已有多种药物应用于该病,本文主要介绍康柏西普在老年性黄斑变性中的应用。     

Fluorescence enhancement of carbon dots by graphene for highly sensitive detection of tetracycline hydrochloride

In this study, fluorescence of self-assembled multilayers (SAMs) of carbon dots (CDs) was found to be enhanced by graphene. The number of polyelectrolyte layers can be tuned to control the distance between CDs and graphene in SAMs. The enhanced fluorescence efficiency was found to be dependent on graphene concentration, degree of graphene reduction, and the distance between CDs and graphene surface. When graphene concentration and polyelectrolyte bilayer number were set to 0.005 mg mL⁻¹ and 3 layers, respectively, fluorescence intensity of CDs could be increased up to 3.2 times. Tetracycline hydrochloride (Tc) could be detected by the established SAMs in the presence of graphene as the sensitivity was 2 orders higher than that of SAMs in the absence of graphene. Limit of detection of this sensing system was 0.9284 nM, which is 1–3 orders of magnitude lower than those of most of reported fluorescence sensors. This method could be successfully applied to detect trace Tc in milk samples.

The fluorescence of carbon dots self-assembled multilayers (CDs SAMs) can be enhanced by graphene, the sensing sensitivity for tetracycline hydrochloride of CDs SAMs with graphene is two orders higher than that of SAMs without graphene.     

Interlayer coupling and the phase transition mechanism of stacked MoS2/TaS2 heterostructures discovered using temperature dependent Raman and photoluminescence spectroscopy

Ultrathin 1T (tetragonal)-TaS₂ and monolayer MoS₂ heterostructures were prepared to study their phase transition (PT) mechanisms and band structure modulation. The temperature dependency of photoluminescence (PL) and Raman spectra was utilized to study interlayer coupling and band structure. The PL results indicate that the band structure of MoS₂/TaS₂ heterostructures undergoes a sharp change at 214 K. This is attributed to the PT of 1T-TaS₂ from a Mott insulator state to a metastable state. In addition, the temperature dependency of the MoS₂/TaS₂ Raman spectra illustrates that the phonon vibration of the heterojunction is softened due to the effect of interlayer coupling. The present work could provide an avenue to create material systems with abundant functionalities and physical effects.

The important interlayer coupling of the MoS₂–TaS₂ heterostructure and the phase transition mechanism of ultrathin 1T-TaS₂ are described.     

The effect of meat processing methods on changes in disulfide bonding and alteration of protein structures: impact on protein digestion products

We investigated the effects of different pork preparation methods (cooked pork, emulsion-type sausage, dry cured pork, and stewed pork) on protein structures and in vitro digestion. Compared with raw meat, processed meats contained lower levels of free sulfhydryl groups (P < 0.05). Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed different protein profiles for pork products treated without or with 5% βME, which indicated different extents of disulfide bond formation. Emulsion-type sausage showed significantly higher α-helix content and lower β-sheet, β-turn, and random coil contents than cooked pork (P < 0.05). Correspondingly, emulsion-type sausage and dry-cured pork had the highest values of surface hydrophobicity (P < 0.05). Proteome data showed that the long salting and drying times used for dry-cured pork as well as long-term high-temperature cooking of stewed pork might alter the accessibility of digestive proteolytic enzymes to the protein cleavage sites.

Processing caused different levels of formation of disulfide bonds, and associated it with protein structure changes and digested products.