Design of Collagen-Based Hemostatic Material for Use in Plastic and Reconstructive Surgery

This study aims to develop collagen-based hemostatic materials. The sheet-shaped collagen sponge was manufactured by freeze-vacuum drying the aqueous solution of collagen (Col) and heat-denatured collagen (Col’) at a composition ratio of 2/1. The both sides or one side of sponge was treated with ultraviolet (UV) irradiation for 15 minutes to introduce intermolecular crosslinks between collagen molecules. The elution behavior of collagen sponge was investigated by immersing the sponge in water for a predetermined time and then by measuring the weight change. The double-sided UV-irradiated sponge showed very slow elution properties. On the other hand, the single-sided UV-irradiated sponge showed initially fast elution and subsequent very slow elution properties. Such initially fast elution of collagen molecules from the surface without UV-irradiation allows an adhesion of collagen sponge to the wound surface and results in hemostatic effect. In addition, the water absorption and retention properties of sponge were investigated by placing the hydrated sponge on a mesh for a predetermined time and then by measuring the weight change. The double-sided UV-irradiated sponge absorbed 81 times more water than own weight and showed a value of 45 times even after 7 days. The single-sided UV-irradiated sponge absorbed 80 times more water than own weight and showed a value of 39 times even after 7 days. The sponge with high water absorption and retention properties allows a wound healing effect because such sponge can absorb large amounts of blood plasma and exudates containing various cell growth factors. The double-sided UV-irradiated sponge is a good candidate for the wound dressing. On the other hand, the single-sided UV-irradiated sponge is a good candidate for the hemostatic material.

Efficacy of forced coagulation with low high-frequency power setting during endoscopic submucosal dissection

To investigated the hemostatic ability of the S and F1-10 methods in clinical and ex vivo studies. METHODSThe hemostatic abilities of the two methods were analyzed retrospectively in all six gastric endoscopic submucosal dissection cases. The treated vessel diameter, compressed vessel frequency, and bleeding frequency after cutting the vessels were noted by the recorded videos. The coagulation mechanism of the two power settings was evaluated using the data recording program and histological examination on macro- and microscopic levels in the ex vivo experiments using porcine tissues. RESULTSF1-10 method showed a significantly better hemostatic ability for vessels ≥ 2 mm in diameter and a trend of overall better coagulation effect, evaluated by the bleeding rate after cutting the vessels. F1-10 method could sustain electrical current longer and effectively coagulate the tissue wider and deeper than the S method in the porcine model. CONCLUSIONF1-10 method is suggested to achieve a stronger hemostatic effect than the S method in clinical procedures and ex vivo models.

Preliminary study on blood coagulation and hemostatic effect and acute toxicity of Oxalis corniculata L.ethanol extract

In the present study,we aimed to observe the effects of ethanol extract of Oxalis corniculata L.on bleeding time(BT)and coagulation time(CT)and determine its acute toxicity in mice.Firstly,the ethanol extract of O.corniculata was administered to 40 mice,which were randomly divided into the normal control group,Yunnan Baiyao control group,low-dose group,and high-dose group.The low-dose(0.6 g/kg)and high-dose(1.2 g/kg)groups received ethanol extract of O.corniculata by gavage,and the BT and CT of the mice were measured by the slide method and tail clipping method,respectively.Secondly,the median lethal dose method was used with 50 mice to observe the physiological state,poisoning reaction,and death of the mice after intragastric administration.Finally,on the 14th day of the experiment,a necropsy was performed to observe any abnormality of the organs.In conclusion,in the coagulation and hemostasis tests,there were no statistical differences between the groups(P>0.05),while there was a significant dose-response relationship,and the BT and CT were significantly shorter than those of the negative control group,which were comparable to the Yunnan Baiyao control group.Moreover,in the acute toxicity test,the median lethal dose of ethanol extract of O.corniculata was 6.0291 g/kg,with a 95%confidence interval of 5.3065–6.7829 mg/kg.