Objective:To assess the status of undernutrition and appropriate catch-up growth in extremely preterm infants within 24 months of corrected age (CA).Methods:A retrospective cohort study was conducted. A total of 422 extremely preterm infants born at Shenzhen Maternity and Child Healthcare Hospital, Women and Children's Medical Center, Southern Medical University from January 2017 to December 2022 and followed up until 24 months of CA were enrolled. The extremely preterm infants were grouped by gestational age at birth (<25, 25-26, 27 weeks), birth weight (<500, 500-749, 750-999,≥1 000 g), weight for gestational age (large for gestational age (LGA), appropriate for gestational age (AGA), small for gestational age (SGA)) and sex. Weight data within 24 months of CA were collected every 3 months. Nutritional insufficiency, growth rate, and achievement of adequate catch-up growth were analyzed during the period from 0 to 24 months of CA. Z-score method was used to analyze data. Fenton 2013 preterm growth charts (Fenton 2013) were used before 40 weeks of corrected gestational age, and World Health Organization child growth standards (2009) fitted Z-scores were applied from 40 weeks of CA. Changes in weight Z-scores of extremely preterm infants from 0 to 24 months of CA were observed and compared, the occurrence of moderate to severe malnutrition and growth retardation was determined, nutritional insufficiency was assessed, and growth rate as well as the achievement of appropriate catch-up growth were analyzed. The Lambda-mu-sigma method combined with the Z-score fitting model was used to fit and analyze the distribution characteristics of weight percentiles in extremely preterm infants. The Chi-square test was used to compare differences among groups.Results:A total of 422 extremely preterm infants were included, with a gestational age at birth of 26.3(25.4, 27.2) weeks and a birth weight of (880±177) g. Among them, 238 were males and 184 were females; 36 cases (8.5%) were LGA, and 16 cases (3.8%) were SGA. During follow-up within 24 month of CA, 89 cases (21.1%) developed moderate to severe malnutrition. When compared separately among different birth weight and gestational age at birth groups, there had both statistically differences in the incidence of moderate to severe malnutrition ( χ2=42.94 and 9.17, both P<0.05). The incidence was the highest in the birth weight of CA<500 g group and the <25 weeks gestational age at birth group, while it was the lowest in the birth weight of CA≥1 000 g group and the 27 weeks gestational age at birth group in their respective groups. Growth retardation occurred in 5.2% (22/422). However, there had statistically differences in the incidence of growth retardation among different birth weight and gestational age at birth groups, in each grouped time interval ( χ2=21.61 and 4.30, both P<0.05). The proportions of rapid growth were relatively high in the 0-3 months and 3-6 months of CA groups, which were 96 cases (27.4%) and 98 cases (26.6%), respectively. Overall, appropriate catch-up growth was achieved in 341 cases (80.8%) from 0 to 24 months of CA. There had statistically differences in the completion rate of appropriate catch-up growth among different birth weight and gestational age at birth groups ( χ2=23.65 and 7.08, both P<0.05). The completion rate was the highest in the birth weight of CA<500 g group and the <25 weeks of gestational age at birth group, while it was the lowest in the birth weight of CA≥1 000 g group and the 27 weeks of gestational age at birth group. Conclusions:The lower the birth weight and gestational age of extremely preterm infants, the higher the incidence of moderate to severe malnutrition and the lower the achievement rate of adequate catch-up growth within 24 months of CA. The period of 0-6 months of CA is the critical window for catch-up in extremely preterm infants.

Hepatitis B virus （HBV） exclusively infects liver parenchymal cells and forms covalently closed circular DNA （cccDNA） within their nuclei. HBV cccDNA serves as the essential template for viral gene transcription， the sole source of progeny virus production， and the key driver of viral antigen expression， and it is the molecular basis for the persistence of HBV infection. Therefore， elimination and/or functional silencing of cccDNA is the key to eradicate chronic HBV infection. This article discusses the critical scientific issues that need to be solved during elimination of the harm of HBV infection from the perspectives of the synthesis， transcription， and clearance of cccDNA， as well as the impact of nonparenchymal cells on cccDNA， in order to provide a reference for eradicating HBV infection in the future.

Objective:To assess the status of undernutrition and appropriate catch-up growth in extremely preterm infants within 24 months of corrected age (CA).Methods:A retrospective cohort study was conducted. A total of 422 extremely preterm infants born at Shenzhen Maternity and Child Healthcare Hospital, Women and Children's Medical Center, Southern Medical University from January 2017 to December 2022 and followed up until 24 months of CA were enrolled. The extremely preterm infants were grouped by gestational age at birth (<25, 25-26, 27 weeks), birth weight (<500, 500-749, 750-999,≥1 000 g), weight for gestational age (large for gestational age (LGA), appropriate for gestational age (AGA), small for gestational age (SGA)) and sex. Weight data within 24 months of CA were collected every 3 months. Nutritional insufficiency, growth rate, and achievement of adequate catch-up growth were analyzed during the period from 0 to 24 months of CA. Z-score method was used to analyze data. Fenton 2013 preterm growth charts (Fenton 2013) were used before 40 weeks of corrected gestational age, and World Health Organization child growth standards (2009) fitted Z-scores were applied from 40 weeks of CA. Changes in weight Z-scores of extremely preterm infants from 0 to 24 months of CA were observed and compared, the occurrence of moderate to severe malnutrition and growth retardation was determined, nutritional insufficiency was assessed, and growth rate as well as the achievement of appropriate catch-up growth were analyzed. The Lambda-mu-sigma method combined with the Z-score fitting model was used to fit and analyze the distribution characteristics of weight percentiles in extremely preterm infants. The Chi-square test was used to compare differences among groups.Results:A total of 422 extremely preterm infants were included, with a gestational age at birth of 26.3(25.4, 27.2) weeks and a birth weight of (880±177) g. Among them, 238 were males and 184 were females; 36 cases (8.5%) were LGA, and 16 cases (3.8%) were SGA. During follow-up within 24 month of CA, 89 cases (21.1%) developed moderate to severe malnutrition. When compared separately among different birth weight and gestational age at birth groups, there had both statistically differences in the incidence of moderate to severe malnutrition ( χ2=42.94 and 9.17, both P<0.05). The incidence was the highest in the birth weight of CA<500 g group and the <25 weeks gestational age at birth group, while it was the lowest in the birth weight of CA≥1 000 g group and the 27 weeks gestational age at birth group in their respective groups. Growth retardation occurred in 5.2% (22/422). However, there had statistically differences in the incidence of growth retardation among different birth weight and gestational age at birth groups, in each grouped time interval ( χ2=21.61 and 4.30, both P<0.05). The proportions of rapid growth were relatively high in the 0-3 months and 3-6 months of CA groups, which were 96 cases (27.4%) and 98 cases (26.6%), respectively. Overall, appropriate catch-up growth was achieved in 341 cases (80.8%) from 0 to 24 months of CA. There had statistically differences in the completion rate of appropriate catch-up growth among different birth weight and gestational age at birth groups ( χ2=23.65 and 7.08, both P<0.05). The completion rate was the highest in the birth weight of CA<500 g group and the <25 weeks of gestational age at birth group, while it was the lowest in the birth weight of CA≥1 000 g group and the 27 weeks of gestational age at birth group. Conclusions:The lower the birth weight and gestational age of extremely preterm infants, the higher the incidence of moderate to severe malnutrition and the lower the achievement rate of adequate catch-up growth within 24 months of CA. The period of 0-6 months of CA is the critical window for catch-up in extremely preterm infants.

Due to the physiological peculiarities of pregnant women, general clinical studies exclude pregnant women. Therefore, there is a lack of evidence of precise medication for pregnant women with diseases worldwide, which poses a significant risk for them to use medication during pregnancy. Whether to include pregnant women as subjects in clinical research has always been a focus of ethical discussion. By providing a broad overview of pregnant women’s participation in clinical research from an ethical perspective, this paper explored the risks and challenges faced by pregnant women’s participation in clinical research, and provided theoretical basis and thinking paths for how to fairly and effectively include pregnant women as subjects and promoting clinical research on pregnant women.

In addition to the typical respiratory symptoms, COVID-19 patients present with clinical manifestations of cardiovascular system damage, and they are at higher risk of intensive care or mortality. The mechanism of COVID-19's impact on the cardiovascular system is still unclear, therefore we need to pay close attention to it. Based on the existing research, this paper focused on the concurrent characteristics of the cardiovascular system diseases, summarized the possible mechanisms of cardiovascular system damage, including the coronavirus invaders directly into cardiomyocytes and its conduction system, with complications or accompanying conditions such as cytokine storm, imbalance of oxygen supply and demand, drug influence, stress and other damage to cardiovascular system. Meanwhile, current clinical manifestations and treatment methods of COVID-19 were summarized.

Objective To study the role of leucine rich repeat neuronal 3 (LRRN3) in the prolif-eration of non-small cell lung cancer and its possible mechanism of expression regulation. Methods The expression of LRRN3 in non-small cell lung cancer was detected by real-time quantitative polymerase chain reaction ( qPCR) , immunohistochemistry and bioinformatics retrieval;A lung cancer cell line A549-LRRN3 with stable over-expression of LRRN3 was established by lentivirus over-expression technology;The effect of LRRN3 on the proliferation of non-small cell lung cancer was detected by methyl thiazolyl tetrazolium ( MTT) assay;Bioinformatics search for changes in methylation of LRRN3 promoter region and treatment of lung cancer cells by methyltransferase inhibitors to detect the effect of methylation on the regulation of LR-RN3 expression; Finally, bioinformatics search analyzes the correlation between LRRN3 and lung cancer prognosis. Results The mRNA expression of LRRN3 in clinical tissues of non-small cell lung cancer (n=12) was significantly lower than that of adjacent normal tissues (n=12) (P=0. 0014). The results of immunohistochemistry showed that the protein expression level of LRRN3 in non-small cell lung adenocar-cinoma was lower than that in normal tissues (P=0. 001), and the expression in non-small cell lung squa-mous cell carcinoma was also lower than that in normal tissues (P=0. 003). Overexpression of LRRN3 in-hibited the proliferation of tumor cells (P<0. 01), and the hypermethylation of LRRN3 in the promoter re-gion inhibited its transcriptional expression. LRRN3 was positively correlated with the survival prognosis of lung adenocarcinoma (P=5. 2e-09;HR=0. 48). Conclusions Hypermethylation in the promoter region of LRRN3 inhibits its transcriptional expression, thereby promoting the proliferation of lung cancer cells.

Objective To explore the role of xCT in the metastasis and drug resistance of nasopharyngeal carcinoma (NPC),to provide new evidences for the mechanism of NPC metastasis and drug resistance,and to enhance effects of chemotherapy.Methods Fluorescence quantitative polymerase chain reaction (PCR) and Western blot were used to detect the xCT expression of 5-8F and 6-10B.The xCT eukaryotic expression vector was constructed to transient transfect 6-10B cell lines.The 5-8F cell lines were treated with xCT antisense oligodeoxynucleotide (ASO).Scratching assay and transwell method were used to detect the cell metastasis and invasion abilities.The expressions of matrix metalloproteinase 1 (MMP1) of all the cell lines were surveyed by Western blot.Results The results of fluorescence quantitative PCR and Western blot showed that the expression of xCT in 5-8F was higher than 6-10B in the levels of mRNA and protein.Exogenous overexpression of xCT enhanced metastasis and invasion abilities of 6-10B cells.Silencing and inhibition of xCT could decrease metastasis and invasion abilities of 5-8F cells.The expressions of MMP1 protein in 5-8F were higher than 6-10B,and they were positively correlated with the expression of xCT.Conclusions xCT is closely related to the metastasis and invasion abilities of nasopharyngeal carcinoma.xCT could enhance the metastasis and invasion abilities of NPC cells.xCT might mediate proliferation and matastasis/invasion of NPC cells through MMP1.