ABSTRACT
Objective:To analyze the risk factors for premature infants with hemodynamically significant patent ductus arteriosus (hs-PDA) requiring surgical treatment, and to explore the indications for surgical treatment in premature infants with hs-PDA.Methods:A nested case-control study was conducted.The data of premature infants with gestational age<30 weeks who were diagnosed with hs-PDA in the Neonatal Intensive Care Unit of Peking Union Medical College Hospital from January 2007 to May 2020 were analyzed retrospectively.The hs-PDA patients treated surgically were included in the operation group.The hs-PDA patients of the same gestational age and gender who were not treated surgically were taken as the control group.The ratio of the case number between the operation and control groups was 1∶2.The clinical data during pregnancy, at birth and after birth of premature infants were compared between the 2 groups.The measurement data were tested by the independent sample t test or Mann- Whitney U test.The classification and enumeration data were compared by the Fisher′ s exact probability method.The risk factors for premature infants with hs-PDA requiring surgical treatment were analyzed by the conditional Logistic regression method. Results:A total of 182 premature infants with hs-PDA were enrolled in the study, including 10 in the operation group and 20 in the control group.The patients underwent PDA ligation 30.5(22.7, 37.0) d after birth, and the median preo-perative invasive ventilation duration was 9.7(17.5, 27.2) d. Compared with the control group(20 cases), the preterm infants in the operation group had a lower birth weight [(891.5±118.0) g vs.(1 054.4±230.2) g, t=2.091], a wider arterial duct diameter [3.2(2.8, 4.0) mm vs.2.0(2.0, 3.0) mm, Z=-3.300], and longer invasive ventilation duration [25.0(18.7, 38.2) d vs.3.0(1.0, 7.5) d, Z=-3.688]. Besides, the operation group applied the pulmonary surfactant for more times [2(1, 3) times vs.1(1, 2) times, Z=-2.440], and inhaled a higher concentration of oxygen on the 14 th day after birth [29(25, 36)% vs.21(21, 29)%, Z=-2.358] than the control group.Moreover, compared with the control group, the operation group took longer to achieve adequate enteral feeding [48.2(51.5, 63.5) d vs.42.5(23.5, 48.0) d, Z=2.789], and gained a higher maximum vasoactive inotropic score (VIS) [3.0(0, 3.5) points vs.0(0, 0) points, Z=-2.630]. The difference in all the above-mentioned indicators between the 2 groups was statistically significant (all P<0.05). Univariate Logistic regression analysis showed that the arterial duct diameter, application times of the pulmonary surfactant, the maximum VIS score, and the time taken to achieve sufficient enteral feeding were all related to the need for surgical treatment of hs-PDA in the operation group (all P<0.05). Multivariate Logistic regression analysis revealed that the invasive ventilation duration ( OR=0.747, 95% CI: 0.560-0.998, P=0.048) was an independent risk factor for hs-PDA premature infants requiring surgical treatment. Conclusions:The factors related to the need for surgical treatment in preterm infants with hs-PDA include a wide arterial duct diameter, multiple applications of the pulmonary surfactant, a high concentration of inhaled oxygen on the 14 th day, and the long time to achieve sufficient enteral feeding.The independent risk factor for the surgical treatment in hs-PDA children is the long invasive ventilation duration.
ABSTRACT
Objective@#To detect antibodies to Coxsackievirus B4 (CV-B4), the indirect enzyme-linked immunosorbent assay (ELISA) method was established and optimized using the recombinant VP1 protein expressed in the prokaryote system as the envelope antigen.@*Methods@#The VP1 gene of CV-B4 was amplified using reverse transcriptase-polymerase chain reaction (RT-PCR). It was ligated into the expression vector pET32a(+ ) to obtain the recombinant plasmid pET32(+ )-VP1 and was then transformed into E. coli expression strain Rosetta (DE3). The recombinant VP1 protein was induced by IPTG, which was verified using SDS-PAGE electrophoresis and mass spectrometry. The establishment and optimization of the indirect ELISA reaction system was based on the purified recombinant protein mentioned above as the coating antigen.@*Results@#The CV-B4 VP1 gene was stably expressed in E. coli in the form of inclusion body. The optimal coating concentration of antigen was 7.5 μg per well and the optimal serum dilution was 1∶100. The threshold for determining the negative and positive result of the serum samples was the optical density value of ≥ 0.376 at 450 nm. The purified recombinant protein could be specifically recognized by CV-B4 positive serum without cross-reaction with Coxsackievirus (CV)-A, CV-B1 and CV-B5, indicating that it has good immunogenicity. However, it can cross-react with CV-B3 serum samples.@*Conclusions@#The indirect ELISA detection method based on the CV-B4 VP1 protein could be used in the detection of serum antibody to CV-B4 infection with good sensitivity, specificity and repeatability.