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BACKGROUND:Medium-and large-diameter polytetrafluoroethylene artificial blood vessels have been widely used in clinical practice.However,most of the products were imported from other countries.Small-diameter porous polytetrafluoroethylene vessels are easy to form thrombosis and intimal hyperplasia,resulting in an extremely low long-term patency rate,which is difficult to fulfill clinical requirements. OBJECTIVE:To review and summarize the research progress of polytetrafluoroethylene in the field of artificial blood vessels,which can provide a reference for the functional modification of small-diameter polytetrafluoroethylene artificial blood vessels and the improvement of their long-term patency rate. METHODS:The relevant articles published from October 2022 to March 2023 in CNKI,Web of Science,Wiley Online Library,SpringerLink,Science Direct and IOP Science databases were searched by the first author.The search terms in Chinese were"porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification".The search terms in English were"ePTFE,porous polytetrafluoroethylene,vascular graft,electrospinning,medical application,functional modification".All the articles about the preparation and modification of polytetrafluoroethylene artificial blood vessels were retrieved. RESULTS AND CONCLUSION:The preparation and functional modification of porous polytetrafluoroethylene artificial blood vessels were still research hotspots and difficult problems.From the research progress in and outside China in recent years,the preparation of porous polytetrafluoroethylene artificial blood vessels mainly adopted the rapid thermal stretching method,but the preparation of polytetrafluoroethylene artificial blood vessels by electrospinning was a promising new method.By analyzing and summarizing different functional modification methods,it was found that the long-term patency rate of porous polytetrafluoroethylene artificial blood vessels had been improved.However,the functional modification of small-diameter polytetrafluoroethylene artificial blood vessels still needed further exploration and optimization.
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Objective:To explore the effect of 1-methyltryptophan (1-MT) on lipopolysaccharide (LPS)-induced permeability and apoptosis of human umbilical vein endothelial cells (HUVECs).Methods:HUVECs were treated with phosphate buffer saline (PBS, control group), 1 μg/mL LPS (LPS group), and LPS combined with 1 mmol/L 1-MT (1-MT group). The expression levels of the p120 concatemer (p120ctn), vascular endothelial (VE) cadherin, caspase-3, and DNA repair enzyme polyadenylate ribose polymerase-1 (PARP) after incubation at 8 h were detected using Western blot. The concentrations of kynurenine (Kyn) after incubation at 2, 4, 6, and 8 h were measured by high-performance liquid chromatography, and indoleamine2, 3-dioxygenase (IDO) activity was calculated. Comparisons among groups were performed using the LSD- t test. Results:Compared with the control group, the expression of caspase-3 [(74.01±7.91)% vs (157.14±7.63)%, P<0.01] and the concentration of Kyn were significantly up-regulated, while the expression of p120ctn [(49.12±2.15)% vs (37.61±1.80)%, P<0.01], VE-cadherin [(107.70±7.01)% vs (90.66±2.58)%, P=0.027], and PARP-1 [(67.95± 3.08)% vs (57.93±5.26)%, P=0.038] were significantly down-regulated, and IDO activity was significantly increased in the LPS group ( P<0.05). Compared with the LPS group, the expression of caspase-3 [(157.14±7.63)% vs (110.74±7.89)%, P<0.01] was significantly down-regulated, while the expression of p120ctn [(37.61±1.80)% vs (47.19±0.82)%, P<0.01], VE-cadherin [(90.66±2.58)% vs (107.27±9.89)%, P=0.029], and PARP-1 [(57.93±5.26)% vs (74.12±4.90)%, P=0.005] were significantly up-regulated, and the activity of IDO was significantly decreased over time in the 1-MT group ( P<0.05). No significant differences were observed between the PBS and 1-MT groups in the protein levels of p120ctn, VE-cadherin, and PARP-1 protein as well as Kyn concentration and IDO activity ( P>0.05), while the expression of caspase-3 was increased in 1-MT group ( P=0.001). Conclusions:LPS aggravates the permeability of HUVECs, which can be reversed by 1-MT via inhibiting IDO activity and reducing Kyn concentrations. Moreover, 1-MT can also reduce apoptosis, which may be via increasing the expression of PARP-1 and reducing the expression of caspase-3, thus protecting endothelial cells.
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Objective To investigate the application of the cross-sectional area ratio of internal jugular vein and common carotid artery (IJV/CCA) in the evaluating the volume responsiveness of critically ill patients. Methods The capacity of critically ill patients were prospectively assessed. The diameter and sectional area of the IJV and CCA were measured by bedside ultrasonography. The cross-sectional area ratio of IJV/CCA was calculated and compared with the variety of cardiac output (ΔCO) after passive leg raising (PLR). Then the correlation index between the cross-sectional area ratio of IJV/CCA and ΔCO was evaluated, and the sensitivity and specificity parameters of capacity status were assessed by the cross-sectional area ratio of IJV/CCA. Results Of 55 critically ill patients in this study, 34 cases had positive volume responsiveness, and 21 case negative volume responsiveness.The general clinical data of the two groups had no statistically significant difference. The cross-sectional area ratio of IJV/CCA in the positive group was significantly less than that of the negative group (1.38±0.55 vs. 2.16±0.68, P<0.01). There was a significant correlation between the IJV/CCA cross-sectional area ratio and the ΔCO value of PLR (r=-0.67, P<0.01). When the ratio of the cross-sectional area of IJV/CCA was 1.65, the sensitivity of the assessment capacity was 86.4％ and the specificity was 78.8％. Conclusions The use of portable bedside ultrasonography is a noninvasive, convenient and reliable method to evaluate the capacity state of the critically ill patients.