Physiology of cold-stored platelets

Platelet transfusions are a life-saving medical intervention used for the treatment of thrombocytopenia or hemorrhage. Extensive research has gone into trying to understand how to store platelets prior to the transfusion event. Much has been learned about storage bag materials, synthetic solutions, and how temperature impacts platelet viability and function. While room temperature storage of platelets preserves 24-hour in vivo platelet recovery and survival there is a greater risk for bacterial growth. Therefore, cold storage of platelets has become attractive due to the reduction in potential bacterial proliferation and the maintenance of platelet function beyond 5 days of storage. Cold stored platelets, however, have their own set of challenges. Cold stored platelets become activated through several mechanisms. The morphological and molecular changes that occur due to cold exposure enhance their ability to participate in the hemostatic process at the cost of rapid clearance from circulation. This review focuses on the underlying mechanisms leading to cold platelet activation and the receptor modifications involved in platelet clearance.     

Macroporous thin membranes for cell transplant in regenerative medicine

The aim of this paper is to present a method to produce macroporous thin membranes made of poly (ethyl acrylate-co-hydroxyethyl acrylate) copolymer network with varying cross-linking density for cell transplantation and prosthesis fabrication. The manufacture process is based on template techniques and anisotropic pore collapse. Pore collapse was produced by swelling the membrane in acetone and subsequently drying and changing the solvent by water to produce 100 microns thick porous membranes. These very thin membranes are porous enough to hold cells to be transplanted to the organism or to be colonized by ingrowth from neighboring tissues in the organism, and they present sufficient tearing stress to be sutured with surgical thread. The obtained pore morphology was observed by Scanning Electron Microscope, and confocal laser microscopy. Mechanical properties were characterized by stress–strain experiments in tension and tearing strength measurements. Morphology and mechanical properties were related to the different initial thickness of the scaffold and the cross-linking density of the polymer network. Seeding efficiency and proliferation of mesenchymal stem cells inside the pore structure were determined at 2 h, 1, 7, 14 and 21 days from seeding.     

1‐(2‐Hydroxyethyl)‐2‐imidazolidinone,a heparanase and matrix metalloproteinase inhibitor,improves epidermal basement membrane structure and epidermal barrier function

Daily exposure to sunlight is known to affect the structure and function of the epidermal basement membrane (BM), as well as epidermal differentiation and epidermal barrier function. The aim of this study is to clarify whether the inhibition of BM‐degrading enzymes such as heparanase and matrix metalloproteinase 9 (MMP‐9) can improve the epidermal barrier function of facial skin, which is exposed to the sun on a daily basis. 1‐(2‐hydroxyethyl)‐2‐imidazolidinone (HEI) was synthesized as an inhibitor of both heparanase and MMP‐9. HEI inhibited not only the BM damage at the DEJ but also epidermal proliferation, differentiation, water contents and transepidermal water loss abnormalities resulting from ultraviolet B (UVB). This was determined in this study by the use of UVB‐induced human cultured skins as compared with the control without HEI. Moreover, topical application of HEI improved epidermal barrier function by increasing water content and decreasing transepidermal water loss in daily sun‐exposed facial skin as compared with non‐treated skins. These results suggest that the inhibition of both heparanase and MMP‐9 is an effective way to care for regularly sun‐exposed facial skin by protecting the BM from damage.     

玻璃体切割联合内界膜剥除治疗糖尿病性黄斑水肿

评估玻璃体切割联合内界膜剥除对糖尿病性黄斑水肿（DME）的疗效。方法：回顾性病例对照研究。2014年6月至2017年1月间因糖尿病视网膜病变合并玻璃体积血或增殖病变于温州医科大学附属眼视光医院杭州院区行玻璃体切割手术治疗，且术前或术中经光学相干断层扫描（OCT）检查确诊合并DME的患者31例（33眼）纳入研究。16例（18眼）术中联合内界膜剥除作为剥膜组，15例（15眼）仅接受玻璃体切割手术治疗者作为对照组。所有手术均由同一医师主刀完成。术后1、3个月随访时复查OCT，对比观察黄斑中心厚度（CMT）和视力的术后变化情况。随访中CMT和最佳矫正视力（BCVA）比较采用重复测量方差分析，组间CMT和BCVA比较采用独立样本t检验。结果：手术前，手术后1、3个月2组间比较LogMAR视力总体差异有统计学意义（F=15.93，P<0.001）。术后 1个月时剥膜组BCVA高于对照组（t=2.55，P=0.02），但术后3个月时2组间差异无统计学意义（t=0.82， P=0.42）。手术前，手术后1、3个月CMT总体差异无统计学意义（F=2.85，P=0.065）。术后1、3个月时，剥膜组的CMT均低于对照组，2组间差异均有统计学意义（t=2.24，P=0.03；t=3.79，P=0.001）。术后1个月时，剥膜组有效（与术前比CMT减少20%以上）、无效（变化不超过20%）及恶化（增厚超过 20%）的例数分别为8、6、4例，术后3个月时则分别为11、5、2例，与对照组相比，术后1个月时组间差异无统计学意义（Z=-1.687，P=0.092），术后3个月时剥膜组DME改善有效比例明显高于对照组，组间差异有统计学意义（Z=-2.177，P=0.029）。结论：对于非牵拉性DME，内界膜剥除有助于术后早期DME消退。