Dwelling time and complications of umbilical venous catheterization with different tip positions in preterm infants: a multicenter prospective cohort study / 中华儿科杂志

Objective: To compare the dwelling time and complications of low lying umbilical venous catheterization (UVC) in preterm infants with that of central UVC. Methods: This was a prospective cohort study. A total of 3 020 preterm infants from 44 neonatal intensive care units (NICU) who had UVC inserted from October 2019 to August 2021 were enrolled. Demographic and general baseline data, dwelling time of UVC and reasons for removal, complications and their occurrence time were collected. According to the position of the catheter tip, the preterm infants were divided into low lying UVC group (insertion depth of 3-5 cm) and central UVC group (the catheter tip was close to the entrance of right atrium, or at the 8th-9th thoracic vertebra level). The Mann-Whitney U test was used to compare the dwelling time and incidence of complications (cases/1 000 catheter days), and the independent t test and Chi-square test were used to compare the characteristics between the 2 groups. The receiver operating characteristic (ROC) curve was used to analyze the optimal cut-off value of UVC dwelling time. Results: Among the included 3 020 preterm infants, 1 624 (53.8%) were males, the gestational age was 29.9 (28.4, 31.6) weeks, the birth weight was (1 264±301) g, and 2 172 (71.9%) premature babies had central UVC. There were no significant differences in the proportion of males, the gestational age and the birth weight of neonates between the 2 groups (all P>0.05). There were also no significant differences in the rate of maternal history, PPROM>18 hours, chorioamnionitis, antenatal antibacterial angents exposure and antibacterial angents usage through UVC (all P>0.05). The dwelling time of central UVC was longer than that of low lying UVC (7 (6, 10) vs. 4 (3, 7) days, U=23.42, P<0.001). The complication incidence of central and low lying UVC were 20.0 and 70.8 cases/1 000 catheter days, respectively. The top 3 complications of central UVC were occlusion, catheter tip migration, and CLABSI (9.3, 3.5, 3.0 cases/1 000 catheter days). The top 3 complications of low lying UVC were catheter occlusion, CLABSI, and catheter tip migration (45.8, 6.3, 5.4 cases/1 000 catheter days). The ROC curve of UVC dwelling time and complications showed that the cut-off values ​​of central UVC and low lying UVC were 6.5 and 4.5 days, respectively. The 2 groups both showed a trend of increases in the 3 complications with the prolonged dwelling time. Cox regression analysis showed that the overall difference in the proportion of occlusion between the central UVC and low lying UVC groups was statistically significant (χ2=30.18, P=0.024). There were both no significant differences in catheter tip migration and CLABSI (both P>0.05). Conclusions: The most common UVC complication in preterm infants is occlusion. It is not recommended to keep a low lying UVC for longer than 4.5 days. During the whole dwelling period, a close monitoring for UVC complications is required.

A cell model for high-throughput screening GLP-1 receptor agonists / 中国药理学通报

Aim To establish a high-throughput screening cell model for GLP-1 receptor agonists. Methods A pEGFP-GLP-1R-3 C recombinant plasmid was constructed and transfected into HEK293T cells. The cells were screened with G418 and flow cytometry. The established stable cell line was named HEK293TGLP-lR-3C-eGFP cell line. The expression level of GLP-1 R-3C-eGFP protein was confirmed by Western blotting and laser confocal microscopy. Then cyclic adenosine monophosphate (cAMP) response element reporter gene was transfected into the HEK293T-GLP-lR-3C-eGFP cells. The luminescence values were detected by One-Step Luciferase Reporter Gene Assay Kit after stimulation with different concentrations of GLP-1 peptide. The luminescence values reflected the cellular cAMP level, which was verified using the cAMP kit (E L I S A). Results HEK293T-GLP-lR-3C-eGFP cell line was successfully constructed. The relative light unit change trend after stimulation with different concentrations of GLP-1 was similar to that of the cellular cAMP level change trend. The value of Z' in this experiment was 0.52. Conclusions A recombinant HEK293T cell line is established, which can be used for high-throughput screening of GLP-1 receptor agonists.