Iodine is an essential micronutrient for human growth and development. It is crucial for neural development in fetuses and newborns in the early postnatal period, including neural migration, glial differentiation, and myelin formation in the central nervous system. Mothers must consume sufficient iodine during pregnancy to maintain fetal growth and development. However, the results of current researches on the potential effects of maternal iodine intake imbalance during pregnancy on offspring iodine nutrition, neurological and physical development are not completely consistant. This article reviews the research in recent years on the effects of maternal iodine intake imbalance during pregnancy on the iodine nutrition and development of offspring, aiming to provide scientific basis for improving offspring development from the perspective of maternal iodine nutrition.

Objective:To construct an entrustable professional activities (EPAs) assessment framework for undergraduate medical students suited to the national conditions in China.Methods:The Delphi method was used to construct an EPAs assessment framework for medical undergraduates. Twenty-one clinical experts across China were invited to participate in two rounds of Delphi consultation.Results:All the 21 experts completed the two rounds of Delphi consultation. The effective questionnaire response rates of the two rounds of consultation were 100.0% (21/21). For the first-round expert consultation, the W values of importance and feasibility scores of EPAs were 0.182 and 0.173 (both P<0.05), respectively. For the second-round expert consultation, the W values of importance and feasibility scores of EPAs were 0.167 and 0.152 (both P<0.05), respectively. According to the second-round Delphi consultation, the importance and feasibility scores of all 14 EPAs indicators were >3.5 points, with the coefficients of variation <0.25 points. We preliminarily established 12 EPAs indicators and 42 key assessment points and determined the expected entrustment levels of each EPA at different stages for medical undergraduates. Conclusion:This study preliminarily constructed an EPAs assessment framework for medical undergraduates, which provides a new evaluation method for the cultivation of medical undergraduates in China.

Objective:To analyze the global epidemic data of Corona virus disease 2019 (COVID-19) and the prevention and control measures, learn about the epidemic characteristics, development trend and the main factors affecting the prevention and control effect, and provide reference for scientific prevention and control of COVID-19.Methods:The data of COVID-19 mainly came from the WHO website and the websites of the United States, European and other Centers for Disease Control and Prevention (the statistical time was from the beginning of the epidemic in each country to March 31, 2022). The epidemiological characteristics and trends in the world and major countries were analyzed, and the main factors affecting the prevention and control of the epidemic were studied. SPSS19.0 software was used to collate data and statistical analysis.Results:The worldwide cumulative confirmed cases of COVID-19 reached 1 million on April 2, 2020, 10 million cases on June 28, 2020, 100 million cases on January 25, 2021, 200 million cases on August 3, 2021, 300 million cases on January 6, 2022, 400 million cases on February 8, 2022, 489 million cases on March 31, 2022. From January 2020 to March 31, 2022, the interval between each additional 100 million cases was gradually shortened (about 360 days from the beginning of the epidemic to the increase to 100 million, the average time to increase from 100 million to 200 million, from 200 million to 300 million was 170 days, and the number of confirmed cases increased from 300 million to 400 million was only 33 days), the epidemic had accelerated. The worldwide cumulative number of death case was 100 000 on April 9, 2020, 1 million on September 19, 2020, 5 million on October 31, 2021, and 6.14 million on March 31, 2022. From January to October 2021, the average time interval for an increase of 1 million deaths was 97 days. After October, the growth rate decreased, averaging 121 days. At the end of 2021, affected by the Omicron mutation, the number of infected people worldwide increased sharply. By March 31, 2022, the cumulative number of confirmed cases in all continents was Europe (181 million), Asia (141 million), North America (94.67 million), South America (56.09 million), Africa (11.55 million) and Oceania (5.58 million) from high to low. The cumulative deaths from high to low was Europe (1.77 million), North America (1.42 million), Asia (1.41 million), South America (1.28 million), Africa (0.25 million) and Oceania (8 900). The top 5 countries with cumulative confirmed cases of COVID-19 were the United States (80.14 million), India (43.03 million), Brazil (29.98 million), France (25.82 million) and the United Kingdom (21.28 million). The top five countries with accumulated deaths were the United States (980 000), Brazil (660 000), India (520 000), the United Kingdom (160 000) and France (140 000).Conclusions:COVID-19 is a global public health emergency. The epidemic has spread worldwide with strong infectivity, rapid transmission and great harm. It is suggested to focus on the prevention and control of key links, strengthen the early warning mechanism, continue to take scientific public health prevention and control measures such as vaccination, reduce severe case and death and deal with an ongoing challenge.

With the effective implementation of universal salt iodization measures to prevent iodine deficiency disorders, severe iodine deficiency in pregnant women has been rare. However, due to the difficulty in changing the state of iodine deficiency in natural environment and insufficient iodine intake in diet to meet the iodine nutritional needs during pregnancy, mild or moderate iodine deficiency in pregnancy still occurs frequently, and may have adverse effects on the development of nervous system of their offspring. At the same time, the effect of excessive iodine intake of pregnant women on the development of nervous system of their offspring can not be ignored. In addition, if the ability of thyroid regulation in pregnant women is out of balance that leads to thyroid dysfunction and even hormone secretion disorder, which can not meet the needs of fetal growth and development, it may also affect the nervous system function of their offspring. This paper summarizes the human population studies in recent years: the effects of maternal mild to moderate iodine deficiency, iodine excess, abnormal thyroid function and thyroid hormone treatment on neuro development of offspring, and the mechanism of corresponding animal iodine related exposure experiments, in order to provide scientific basis for "precise prevention and treatment" of iodine deficiency disorders in the future.

Objective:To evaluate the effect of ionizing radiation on chromosome aberration of peripheral blood lymphocytes in children with vascular interventional procedure.Methods:The chromosome aberration of peripheral blood lymphocytes was analyzed before and after vascular interventional procedure to assess the effect of low-dose ionizing radiation on chromosomes. Peripheral blood (PB) was collected using heparin as an anticoagulant from 26 patients before and after (within 10 minutes) vascular interventional surgery. Informed consent was obtained from the patients′ parents.Results:Dicentric + centric ring (dic+ r) formation increased significantly ( U=647, P<0.01) in peripheral blood lymphocytes of children after interventional operation. No correlation was observed between the rate of dic+ r and the cumulative dose (CD), dose area product (DAP), age, body weight, gender and the estimated effective dose E ( P>0.05). There was no significant difference in dic+ r rate of children between different genders, ages and lesion sites ( P>0.05). The dic+ r rate after interventional operation exceeded 40×10 -3 in 4 of 26 cases with the highest of 95.83×10 -3. Conclusions:The ionizing radiation during children′s vascular interventional procedure might lead to the increase of chromosome aberration of peripheral blood lymphocytes and some children are abnormally sensitive. Great attention should be paid to the justification and radiation protection during interventional procedure for children.

Objective:To observe the epidemiological characteristics and transmission chain of COVID-19 in Harbin, and to provide epidemiological evidence for improving the COVID-19 preventive measures and optimizing prevention and control strategies.Methods:The epidemic situation of COVID-19 in Harbin in January 2021 was analyzed by using the Infectious Disease Report Information Management System and the Public Health Emergency Management Information System of the China Disease Prevention and Control Information System, the epidemic situation information publicly released by the Heilongjiang Provincial Health Commission, and the epidemiological report of Heilongjiang Province Certer for Disease Control and Prevention and Harbin Center for Disease Control and Prevention. The main transmission chains were sorted out through combination of epidemiological field investigation, serological testing, gene sequencing, big data and other means.Results:From January 12 to February 4, 2021, 295 cases of COVID-19 infection (including confirmed cases and asymptomatic infections) were reported in Harbin, which affected 6 districts of Harbin and were concentrated in 41 of the 274 townships in the city. The sex ratio of male to female was 1.00∶1.12 (139∶156); the age ranged from 1 to 86 years old, and the median age was 45 years old. The proportion of confirmed cases and asymptomatic infection was 1.00 ∶ 1.02 (146 ∶ 149), and there was a significant difference in the distribution of different ages between them ( P = 0.042). The cases were mainly found through the health screening of the centralized isolation personnel (178 cases, 60.3%). Other detection methods included active screening (87 cases, 29.5%), screening of the home isolation personnel (26 cases, 8.8%), and medical treatment in medical institutions (4 cases, 1.4%). The main transmission chain of the outbreak was the case associated with a food processing enterprise, with a total of 259 cases, accounting for 87.8% of the total cases. The gene sequencing results showed that the case sequence was homologous with that of Wangkui County, Suihua City, Heilongjiang Province. Conclusions:A food processing enterprise is involved in the main transmission chain, which indicates that the epidemic prevention and control measures needs to be further optimized. Specifically, the supervision and management of food processing enterprises, cold chain storage companies and other enterprises should be strengthened. High attention should be paid to the hidden dangers of COVID-19 in large and medium sized enterprises with hermetic space in Harbin.

Objective:To evaluate the intelligence, movement and physical development of 2-month-old infants, and to explore the influencing factors of early infant development.Methods:A total of 203 infants aged 42 days who underwent physical examination in the Department of Neonatology of the Fourth Affiliated Hospital of Harbin Medical University from May to December 2021 were selected as subjects. At the age of 2 months, 184 infants were followed up for their intelligence, movement and physical development. The intelligence and movement development of infants were evaluated with the intelligence development scale. Their body length, weight, and head circumference were measured, and physical development was assessed by Z-score method. Logistic regression was used to analyze the influencing factors of intelligence, movement and physical development of 2-month-old infants.Results:The median mental developmental index (MDI) of 184 2-month-old infants was 101; the median psychomotor developmental index (PDI) was 89; the body length was (59.3 ± 2.0) cm, the body weight was (5.8 ± 0.6) kg, and the head circumference was (38.9 ± 1.1) cm. Multiple logistic regression analysis showed that the influencing factors of MDI were maternal delivery age and infant gestational age [odds ratio ( OR) = 0.849, 0.463, P < 0.05]; the influencing factors of PDI were maternal prenatal education and average sleep time per night during pregnancy ( OR = 0.512, 0.666, P < 0.05); the influencing factor of body mass index (BMI) was maternal iodine supplements during pregnancy ( OR = 2.858, P = 0.018); the influencing factor of length-for-age Z-score (LAZ) was maternal prenatal education during pregnancy ( OR = 0.265, P = 0.026); the influencing factors of weight-for-age Z-score (WAZ) included maternal average sleep time per night, the frequency of sleeping time exceeding 12 am and the average weekly exercise duration during pregnancy ( OR = 0.277, 1.106, 0.990, P < 0.05). Conclusion:Maternal delivery age, prenatal education, sleep duration, intake of iodine supplements, exercise duration during pregnancy, and infant gestational age are factors affecting the intelligence, movement and physical development of 2-month-old infants, which should be paid attention to and measures should be taken to improve the population quality.

Objective:To explore the arsenic trioxide (As 2O 3)-induced apoptosis of human neuroblastoma cells (SH-SY5Y cells) and the protection mechanisms of folic acid (FA) and vitamin B 12 (VB 12). Methods:SH-SY5Y cells were cultured in vitro and divided into six groups by group design: control group (normal cultured), arsenic exposed group (10.00 μmol/L As 2O 3), FA intervention group (0.30 mmol/L FA + 10.00 μmol/L As 2O 3), VB 12 intervention group (0.06 mmol/L VB 12 + 10.00 μmol/L As 2O 3), combined intervention group (0.30 mmol/L FA + 0.06 mmol/L VB 12 + 10.00 μmol/L As 2O 3) and reagent control group (0.30 mmol/L FA + 0.06 mmol/L VB 12). Cells in each group were cultured for 24 h ( n = 3). Flow cytometry was used to determine the apoptosis rate of cells in each group. Transmission electron microscopy was used to observe the ultrastructural changes of the cells. The expression levels of mRNA and protein of apoptosis-related indicator B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X (Bax) were detected by fluorescence quantitative PCR and Western blotting. The activity of cysteinyl aspartate specific proteinase (Caspase) 3 was detected by luminescent assay. The above indicators were statistically analyzed. Results:There was statistically significant difference in the apoptosis rate among different groups ( F = 213.036, P < 0.05). The apoptosis rate in arsenic exposed group [(44.43 ± 3.54)%] was higher than that in control, FA intervention, VB 12 intervention, and combined intervention groups [(1.80 ± 0.06)%, (14.37 ± 0.13)%, (19.10 ± 1.56)%, (17.11 ± 2.34)%, P < 0.05]. Under transmission electron microscope, the apoptotic bodies, mitochondria swelling and degeneration, chromatin agglutination were observed in SH-SY5Y cells exposed to arsenic. The morphological and organelle changes of SH-SY5Y cells were significantly improved after respective and combined intervention of FA and VB 12. The expression levels of Bcl-2, Bax mRNA and protein were significantly different among different groups ( F = 5.178, 7.169, 6.142, 9.194, P < 0.05). The expression level of Bcl-2 protein in arsenic exposed group was lower than that in control group ( P < 0.05), and the expression levels of Bax mRNA and protein were higher than those in control group ( P < 0.05). The expression levels of Bcl-2 mRNA and protein in FA intervention group and combined intervention group were higher than those in arsenic exposed group ( P < 0.05), and Bcl-2 mRNA expression level in VB 12 intervention group was higher than that in arsenic exposed group ( P < 0.05). The expression levels of Bax mRNA and protein in FA intervention, VB 12 intervention and combined intervention groups were lower than those in arsenic exposed group ( P < 0.05). There were statistically significant differences in Caspase 3 activity among different groups ( F = 84.604, P < 0.05). Caspase 3 activity in arsenic exposed group was significantly higher than those in control, FA intervention, VB 12 intervention, and combined intervention groups ( P < 0.05). Conclusions:Arsenic exposure can lead to apoptosis and ultrastructural changes of SH-SY5Y cells. FA and VB 12 may effectively inhibit apoptosis through regulating Bcl-2/Bax pathway and decrease Caspase 3 activity, thus playing a protective role on nerve cells.

Objective:To explore the effect of fluoride exposure on the gene expression of phosphatidylinositol-3-kinase/protein kinase B/endothelial nitric oxide synthase (PI3K/Akt/eNOS) in rat aortic tissue, and to provide a theoretical basis for studying the mechanism of cardiovascular injury caused by endemic fluorosis.Methods:A total of 40 male Wistar rats were divided into 4 groups (10 rats in each group) via the random number table method according to body weight (80 - 100 g), namely control group (drinking distilled water), low-dose, medium-dose and high-dose groups [drinking distilled water containing 50, 100 and 150 mg/L sodium fluoride (NaF), respectively]. The rats were free to drink and eat. After feeding for 90 days, rats were sacrificed and the aortic tissue was taken. Three aortic tissue samples from the control group and the high-dose group were taken for mRNA sequencing, the differential genes were screened, and the differential genes were analyzed by GO function enrichment analysis and KEGG function enrichment analysis. At the same time, the mRNA expression levels of PI3K, Akt and eNOS in the aortic tissue of rats in each group were determined by real-time fluorescence quantitative PCR.Results:Compared with control group, there were 756 differential genes in high-dose group, including 654 up-regulated genes and 102 down-regulated genes. These differential genes were mainly related to biological processes such as muscle contraction, muscle regulation, muscle tissue development, striated muscle cell development, muscle cell differentiation, blood circulation regulation and striated muscle tissue development. They were mainly enriched in cyclic guanosine phosphate (cGMP-PKG) signaling pathway, relaxin signaling pathway and PI3K/Akt signaling pathway, etc. Compared with control group, the mRNA expression levels of PI3K and eNOS in aortic tissue of rats in low-dose, medium-dose and high-dose groups were significantly reduced ( P < 0.05); the mRNA expression level of Akt in low-dose group was significantly increased ( P < 0.05). Conclusion:Fluoride exposure has certain effects on the function and gene expression of rat aortic tissue, and PI3K/Akt/eNOS signaling pathway may play an important role in the process of fluoride induced aortic tissue injury in rats.

Arsenic is a pollutant widely distributed in the natural environment.The liver is one of the main target organs of arsenic toxicity.Arsenic causes liver damage and liver disease by affecting the imbalance of hepatocyte apoptosis.However,its specific mechanism is not very clear.In this paper,the research on pathways and influencing factors of arsenic-induced hepatocyte apoptosis in recent years is reviewed,which might provide a reference for the mechanism study and clinical prevention of liver injury in the future.