ABSTRACT
BACKGROUND:Hot-melt adhesive is safe and environmental friendly adhesive due to free of solvent, which is particularly suitable for medical applications. OBJECTIVE:To describe the types and characteristics of currently used hot-melt adhesives and to prospect the technical research and development of hot-melt adhesive for polyolefin tubes or catheters as wel as to point out the corresponding key points to the hot-melt adhesion. METHODS:Literature search was carried out in SCI, Elsevier, and CNKI with the key words of“hot melt adhesive, medical application”in English and Chinese, respectively, for the initial retrieval of relevant articles or patents published January 1995 to December 2015. RESULTS AND CONCLUSION:To date, the medical hot-melt adhesives reported in the literature could be grouped as amorphous polyolefin, thermoplastic elastomer, acrylic and polyurethane types. The heat resistance of the most of the hot-melt adhesives does not meet the requirement for steam sterilizing process. In the present review, a strategy is proposed to develop a novel hot-melt adhesive which is good for binding polyolefin parts and can undergo the sterilization process. Given this, it is essential to choose a kind of polypropylene random copolymer with a suitable melting point as a substrate. With the aid of an adjuvant agent, therefore, we can develop a novel hot-melt adhesive that exhibits a lower melting point than the polyolefin tube, withstands steam sterilization temperature to ensure that the tube is not deformed during melt adhesion and is not become invalid during sterilization.
ABSTRACT
BACKGROUND:To ensure the catheter position is very important for interventional catheters. In emergency, rapid and accurate catheter insertion is required. Ultrasound can real-time track the movement of catheters in vivo. It is safe to patient, which has exhibited a bright future in catheter placement. OBJECTIVE: To compare the current methods for improving ultrasonic localization methods and to prospect the future development and improvement of real-time ultrasonic localization of catheters in vivo. METHODS: Literature search was carried out based on PubMed (1990-01/2015-04) and Espacenet with the key words of catheter, ultrasonic guidance, ultrasound localization, enhanced localization for the initial retrieval of relevant articles. RESULTS AND CONCLUSION:To improve the image quality and increase the accuracy of catheter placement by ultrasound, recent efforts have been focused on two paths. One is to improve the resolution of ultrasonic images by enhancing ultrasound equipment or ultrasonic guidance system. The other is to modify catheter itself to obtain high acoustic impedance differential and improve its echogenicity. The latter approach can be potentialy applied in al kinds of catheters and is more economical and practical. Therefore, in future researches, innovation and design of catheter materials for catheter fabricating wil play an important role in promoting the real-time ultrasonic localization of catheters.
ABSTRACT
The selective removal of low density lipoprotein (LDL) and fibrinogen (Fib) by degraded carrageenan was studied by the present authors. Degraded carrageenan was prepared by acid with carrageenan as the main material. The effects of acid conditions on the molecular weight were investigated, and the proper reaction conditions were ascertained. The results of infrared spectrometry indicated that the degraded carrageenan is a heparin-like polysaccharide. Then the selective removal of LDL/Fibrinogen by degraded carrageenan was studied. When molecular weight was about 10,000, pH was 5.10 and the concentration of degraded carrageenan was 800 mg/L, the average reduction percentages were 60.0% for total cholesterol(TC), 79.4% for LDL and very low-density lipoprotein (VLDL), and 93.8% for fibrinogen. There were no significant changes with relation to the level of high-density lipoprotein (HDL) and total protein (TP). So, degraded carrageenan was shown to be of good selectivity on plasma LDL/Fibrinogen apheresis.