[A multicenter study of the birth condition of preterm infants and the causes of preterm birth in Henan Province, China].

OBJECTIVE: To investigate the birth condition of preterm infants and the causes of preterm birth in Henan Province, China, and to provide a basis for the prevention and treatment of preterm birth. METHODS: An epidemiological investigation was conducted for live-birth preterm infants who were born in 53 hospitals in 17 cities of Henan Province from January 1, 2019 to December 31, 2019 to investigate the incidence rate of preterm birth, the distribution of gestational age and birth weight, the use of antenatal glucocorticoids, and the causes of preterm birth. RESULTS: The incidence rate of preterm birth was 5.84% (12 406/212 438) in the 53 hospitals. The proportions of preterm infants with gestational ages of < 28 weeks, 28 - < 32 weeks, 32 - < 34 weeks, and 34 - < 37 weeks were 1.58% (196/12 406), 11.46% (1 422/12 406), 15.18% (1 883/12 406), and 71.78% (8 905/12 406) respectively. The proportions of preterm infants with birth weights of < 1 000 g, 1 000- < 1 500 g, 1 500- < 2 500 g, 2 500- < 4 000 g, and ≥ 4 000 g were 1.95% (240/12 313), 8.54% (1 051/12 313), 49.53% (6 099/12 313), 39.59% (4 875/12 313), and 0.39% (48/12 313) respectively. The infants born by natural labor accounted for 28.76% (3 568/12 406), and those born by cesarean section accounted for 70.38% (8 731/12 406). The rate of use of antenatal glucocorticoids was 52.52% (6 293/11 983) for preterm infants and 68.69% (2 319/3 376) for the preterm infants with a gestational age of < 34 weeks. Iatrogenic preterm labor was the leading cause of preterm birth[40.06% (4 915/12 270)], followed by spontaneous preterm birth[30.16% (3 701/12 270)] and preterm birth due to premature rupture of membranes[29.78% (3 654/12 270)]. The top three causes of iatrogenic preterm birth were hypertensive disorders of pregnancy[47.12% (2 316/4 915)], fetal intrauterine distress[22.85% (1 123/4 915)], and placenta previa/placental abruption[18.07% (888/4 915)]. CONCLUSIONS: There is a relatively low incidence rate of preterm birth in Henan Province, and late preterm infants account for a relatively high proportion. Iatrogenic preterm birth is the main cause of preterm birth in Henan Province, and hypertensive disorders of pregnancy and fetal intrauterine distress are the main causes of iatrogenic preterm birth.

The association of γδ-T cells with bronchopulmonary dysplasia in premature infants.

BACKGROUND: As the survival rate of premature infants increases, the incidence of bronchopulmonary dysplasia (BPD), a chronic complication of premature infants, is also higher than before. The pathogenesis of BPD is complicated, and immune imbalance and inflammatory response may play important roles in it. OBJECTIVE: To investigate the correlation between lymphocyte subsets in peripheral blood, especially γδ-T cells, and BPD of preterm infants. MATERIALS AND METHOD: The study was carried out with the peripheral blood of premature infants (GA < 32 weeks, BW < 1500 g), which were collected at 24 h or 3-4 weeks after birth. The infants were divided into non-BPD groups and BPD groups that were classified as mild or moderate and severe in preterm infants based on the magnitude of respiratory support at 28 days age and 36 weeks postmenstrual age. The γδ-T, CD3+, CD4+, CD8+ and total lymphocyte subsets in peripheral blood were detected by flow cytometry. RESULTS: The percentages of T lymphocyte subsets in peripheral blood were not different between BPD and non-BPD within 24 h after birth. And no significant difference was found in T lymphocyte subsets among neonates with BPD of different severities. However, the infants who developed BPD had a significant increase in γδ-T cells compared to non-BPD ones within 3-4 weeks after birth. CONCLUSIONS: It seems that γδ-T cells in peripheral blood are correlated with BPD. However, the causality of BPD and various lymphocytes remains unclear, which need to be further studied.

[An assessment of white matter development in preterm infants with bronchopulmonary dysplasia using diffusion tensor imaging].

OBJECTIVE: To assess white matter development in preterm infants with bronchopulmonary dysplasia (BPD) using fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of diffusion tensor imaging (DTI). METHODS: Ninety-six infants with a gestational age of ≤32 weeks and a birth weight of <1 500 g who were admitted to the neonatal intensive care unit within 24 hours after birth from August 2016 to April 2019 and underwent head MRI and DTI before discharge were enrolled. According to the discharge diagnosis, they were divided into BPD group with 48 infants and non-BPD group with 48 infants. The two groups were compared in terms of FA and ADC values of the same regions of interest on DTI image. RESULTS: There were no significant differences in the incidence rates of periventricular/intraventricular hemorrhage, periventricular leukomalacia, and punctate white matter lesions between the two groups (P>0.05). Compared with the non-BPD group, the BPD group had significantly lower FA values and significantly higher ADC values of the posterior limb of the internal capsule, the splenium of the corpus callosum, the occipital white matter, the cerebellum, and the cerebral peduncle (P<0.05). Compared with the non-BPD group, the BPD group had a significantly higher frequency of apnea, a significantly higher proportion of infants with pneumonia or mechanical ventilation, and a significantly longer duration of assisted ventilation (P<0.05). CONCLUSIONS: BPD may has potential adverse effects to white matter development in preterm infants, leading to delayed white matter development. Therefore, it is necessary to pay attention to the neurological function of these infants.

[Risk factors for poor prognosis of neonatal bacterial meningitis].

OBJECTIVE: To investigate the risk factors for poor prognosis of neonatal bacterial meningitis. METHODS: A retrospective analysis was performed for the clinical data of 152 children with neonatal bacterial meningitis. According to their prognosis, they were divided into a good prognosis group with 122 children and a poor prognosis group with 30 children. The two groups were compared in terms of general status, initial symptoms, and laboratory findings, and the risk factors for poor prognosis were analyzed. RESULTS: Compared with the good prognosis group, the poor prognosis group had a significantly higher proportion of children with a very low birth weight, a peripheral blood white blood cell count (WBC) of <5×109/L or >20×109/L, a C-reactive protein level of >50 mg/L, a cerebrospinal fluid (CSF) WBC of >500×106/L, a CSF glucose level of <1 mmol/L, or a CSF protein level of >2 g/L, as well as significantly higher positive rates of blood culture and/or CSF culture, Gram-positive bacteria, and Streptococcus agalactiae (P<0.05). The multivariate logistic regression analysis showed that a CSF glucose level of <1 mmol/L and a CSF protein level of >2 g/L were independent risk factors for poor prognosis of neonatal bacterial meningitis. CONCLUSIONS: A CSF glucose level of <1 mmol/L and a CSF protein level of >2 g/L are risk factors for poor prognosis of neonatal bacterial meningitis.

[Hyper-spectral estimation of soil organic matter content based on wavelet transformation].

A total of 60 soil samples with approximate contents of N, P, and K and greatly different content of organic matter were selected by statistical analysis. Through hyper-spectral detection and analysis, the first derivative spectrum of the soil logarithmic reflectance was obtained, and was decomposed by the Bior 1.3 wavelet function. The approximative signal of the lowest frequency and the noise signal of the highest frequency were removed from the input spectrum so as to obtain the characteristic spectrum corresponding to soil physical and chemical parameters. The sensitive bands of soil organic matter were selected by correlation analysis, and the forecasting models were built by multiple regression analysis, based on the sensitive bands and the characteristic spectrum, respectively. Through comparison analysis, the optimal wavelet decomposing resolution for extracting the characteristic spectrum of soil organic matter was ascertained, and the best forecasting model was established. The best wavelet decomposing resolution was 9, followed by 8 and 10. Based on the characteristic spectrum of wavelet decomposing of 9 resolutions, the model R2 reached 0.89, which was increased by 0.31 as compared to the model based on sensitive bands, and increased by 0.10 as compared to the model based on the original spectrum.