Magnetic navigation-assisted colonoscopic enteral tube placement in swine (with video): a preliminary study.

BACKGROUND: Colonoscopic enteral tube placement using current methods has some shortcomings, such as the complexity of the procedure and tube dislodgement. The magnetic navigation technique (MNT) has been proven effective for nasoenteral feeding tube placement, and is associated with reduced cost and time to initiation of nutrition. This study attempted to develop a novel method for enteral tube placement using MNT. METHODS: The MNT device consisted of an external magnet and a 12 Fr tube with a magnet at the end. Ten swine were used, and bowel cleansing was routinely performed before colonoscopy. Intravenous anesthesia with propofol and ketamine was administered. A colonoscopic enteral tube was placed using the MNT. The position of the end of the enteral tube was determined by radiography, and angiography was performed to check for colonic perforations. Colonoscopy was used to detect intestinal mucosal damage after tube removal. RESULTS: MNT-assisted colonoscopic enteral tube placement was successfully completed in all pigs. The median operating time was 30 (26-47) min. No colon perforation was detected on colonography after enteral tube placement, and no colonic mucosal bleeding or injury was detected after the removal of the enteral tube. CONCLUSIONS: MNT-assisted colonoscopic enteral tube placement is feasible and safe in swine and may represent a valuable method for microbial therapy, colonic drainage, and host-microbiota interaction research in the future.

[Sorption Behaviors of Copper Ions and Tetracycline on Microplastics in Aqueous Solution].

The interaction between microplastics, heavy metals, and antibiotics can lead to combined pollution, which could result in greater environmental damage. The pathway and mechanism of the interaction between microplastics, heavy metals, and antibiotics are the preconditions for evaluating the associated environmental risk; however, these are not well understood. As probe sorbates, the sorption behaviors of copper ions (Cu2+) and tetracycline (TC) on two microplastics [high density polyethylene (HPDE) and general-purpose polystyrene (GPPS)] in aqueous solution were investigated and the welding theory with relevant experimental results were discussed. The adsorption capacity of HDPE was greater than that of GPPS in a single Cu solution, whereas the reverse situation occurred in a single TC solution. Moreover, the adsorption capacity of the microplastics in a Cu2+-TC binary solution was larger than that in the single solutions. The pseudo-second-order kinetic models to describe the adsorption process were reasonable and the entire process could be divided into two phases:surface adsorption and internal diffusion. The Langmuir model provided a better fit of the data than did the Freundlich model. In the single solutions, the saturated adsorption amounts of Cu2+ and TC were 0.178 µmol·g-1 and 0.257 µmol·g-1, respectively, for GPPS, and 0.334 µmol·g-1 and 0.194 µmol·g-1, respectively, for HDPE. In the binary solution, the corresponding numerical values were 0.529 µmol·g-1 and 0.411 µmol·g-1, respectively, for GPPS and 0.471 µmol·g-1 and 0.341 µmol·g-1, respectively, for HDPE. The variations in the surface morphological characteristics and chemical functional groups were the main reasons for the difference in the adsorption behavior of microplastics. The variation of the pH of the adsorption system could change the existing forms and surface electrical properties of microplastics and adsorbed objects, and subsequently affected the equilibrium adsorption capacity. When the ambient temperature was in the range of 15 to 35℃, increasing the temperature was unfavorable for the adsorption process. Cu2+ and TC could produce a synergistic effect under the conditions of coexistence. The formation of complexes and bridging make Cu2+ and TC more easily adsorbed by microplastics.