Advances of Long Noncoding RNAs-mediated Regulation in Reproduction / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>Advances in genomics and molecular biology have led to the discovery of a large group of uncharacterized long noncoding RNAs (lncRNAs). Emerging evidence indicated that many lncRNAs function in multiple biological processes and its dysregulation often causes diseases. Recent studies suggested that almost all regulatory lncRNAs interact with biological macromolecules such as DNA, RNA, and protein. LncRNAs regulate gene expression mainly on three levels, including epigenetic modification, transcription, and posttranscription, through DNA methylation, histone modification, and chromatin remodeling. LncRNAs can also affect the development of diseases and therefore be used to diagnose and treat diseases. With new sequencing and microarray techniques, hundreds of lncRNAs involved in reproductive disorders have been identified, but their functions in these disorders are undefined.</p><p><b>DATA SOURCES</b>This review was based on articles published in PubMed databases up to July 10, 2017, with the following keywords: "long noncoding RNAs", "LncRNA", "placentation", and "reproductive diseases".</p><p><b>STUDY SELECTION</b>Original articles and reviews on the topics were selected.</p><p><b>RESULTS</b>LncRNAs widely participate in various physiological and pathological processes as a new class of important regulatory factors. In spermatogenesis, spermatocytes divide and differentiate into mature spermatozoa. The whole process is elaborately regulated by the expression of phase-specific genes that involve many strains of lncRNAs. Literature showed that lncRNA in reproductive cumulus cells may contribute to the regulation of oocyte maturation, fertilization, and embryo development.</p><p><b>CONCLUSIONS</b>LncRNA has been found to play a role in the development of reproduction. Meanwhile, we reviewed the studies on how lncRNAs participate in reproductive disorders, which provides a basis for the study of lncRNA in reproduction regulation.</p>

Breast milk lead and cadmium levels in suburban areas of Nanjing, China / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To evaluate levels of lead (Pb) and cadmium (Cd) in the breast milk in the second postpartum month, to investigate the relationship between Pb/Cd levels in breast milk and some sociodemographic parameters, and to explore whether these levels affect the infants' physical status or the mothers' psychological status (postpartum depression).</p><p><b>METHODS</b>A cross-sectional study was conducted between November 2009 and December 2010. Altogether 170 healthy mothers were enrolled from Nanjing Maternity and Child Health Care Hospital. The inclusion criteria were: voluntary to participate in this study, healthy, with no chronic disease, breastfeeding in the second postpartum month, living in a suburban but not non-industrial area of Nanjing, and not occupationally exposed to toxic metals. All the mothers completed a questionnaire and were evaluated based on the Edinburgh Postpartum Depression Scale (EPDS) to identify the risk of postpartum depression. Pb and Cd levels in breast milk were determined by inductively coupled plasma mass spectroscopy. The infants of these mothers were examined for their z scores of weight for age, length for age, head circumference for age, and body mass index for age.</p><p><b>RESULTS</b>The median breast milk levels of Pb and Cd were 40.6 μg/L and 0.67 μg/L, respectively. In 164 (96.5%) of the 170 samples, Pb levels were higher than the limit reported by the World Health Organization (> 5 μg/L). Breast milk Cd level was > 1 μg/L in 54 (31.8%) mothers. The mothers with a history of anemia had a higher breast milk Pb level than those without a history of anemia (41.1 μg/L vs. 37.9 μg/L, P = 0.050). The median breast milk Cd level in those who were active and passive smokers during pregnancy was significantly higher than that in non-smokers (0.88 μg/L vs. 0.00 μg/L, P = 0.025). The breast milk Cd level in the mothers not taking iron and vitamin supplements for 2 months postpartum was higher than in those taking the supplements (iron supplement: 0.74 μg/L vs. 0.00 μg/L, P = 0.025; vitamin supplement: 0.78 μg/L vs. 0.00 μg/L, P = 0.005). Breast milk Cd level at the second postpartum month was negatively correlated with the z scores of head circumference (r = - 0.248, P = 0.042) and weight for age at birth (r =- 0.241, P = 0.024) in girls. No correlation was found between the breast milk Pb/Cd levels and the EPDS scores.</p><p><b>CONCLUSION</b>Considering the high levels of Pb and Cd in breast milk in this study, breast milk monitoring programs are necessary.</p>

Blood lead levels during pregnancy and its influencing factors in Nanjing, China / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the blood lead levels (BLLs) in the duration of pregnancy and 6-12 weeks after delivery, and analyze the influencing factors of BLLs in healthy pregnant women.</p><p><b>METHODS</b>Pregnant women were recruited from September 2009 to February 2010 at the prenatal clinic in Nanjing Maternity and Child Health Care Hospital. Altogether 174 healthy pregnant women without pregnant or obstetric complications or abnormal pregnancy outcomes were enrolled as the gravida group, and 120 healthy non-pregnant women as the control group. BLLs during pregnancy were determined by flame atomic absorption spectroscopy.</p><p><b>RESULTS</b>BLLs in all the three pregnancy trimesters and postpartum were 59.8±24.3, 55.4±20.1, 55.9±19.7, and 67.6±17.4 μg/L, respectively, and the mean BLL in control group was 67.5±21.3 μg/L. BLLs during all the three trimesters were lower in the gravida group than in the control group (P=0.043, 0.021, and 0.028). Furthermore, occupations, nutrients supplementation, and time of house/apartment painted were associated with BLLs in pregnant women. Lead-related occupations, cosmetics use, and living in a house painted less than 1 year before are risk factors of high BLLs among pregnant women, while calcium, iron, zinc, and milk supplements are protective factors.</p><p><b>CONCLUSION</b>Supplementing calcium, iron, zinc, and milk, or avoiding contact with risk factors may help people, especially pregnant women, to reduce lead exposure.</p>

Neurotoxicity and biomarkers of lead exposure: a review / 中国医学科学杂志(英文版)

Appropriate selection and measurement of lead biomarkers of exposure are critically important for health care management purposes, public health decision making, and primary prevention synthesis. Lead is one of the neurotoxicants that seems to be involved in the etiology of psychologies. Biomarkers are generally classified into three groups: biomarkers of exposure, effect, and susceptibility.The main body compartments that store lead are the blood, soft tissues, and bone; the half-life of lead in these tissues is measured in weeks for blood, months for soft tissues, and years for bone. Within the brain, lead-induced damage in the prefrontal cerebral cortex, hippocampus, and cerebellum can lead to a variety of neurological disorders, such as brain damage, mental retardation, behavioral problems, nerve damage, and possibly Alzheimer's disease, Parkinsons disease, and schizophrenia. This paper presents an overview of biomarkers of lead exposure and discusses the neurotoxic effects of lead with regard to children and adults.

Towards prenatal biomonitoring in Nanjing, China: lead and cadmium levels in the duration of pregnancy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Prenatal lead and cadmium exposure will not only influence the mother' organ systems, but also will provide an environment that may influence the fetus and neonate in a harmful way.In the present study, we detected the blood lead levels (BLLS) and cadmium levels for the duration of pregnancy and 6-12 weeks after delivery and to analyze the influencing factors of BLLs in healthy pregnant women.</p><p><b>METHODS</b>A cohort study survey was carried out. We recruited 174 healthy pregnant women without pregnancy or obstetric complications or abnormal pregnancy outcomes as the gravida group, and 120 healthy non-pregnant women as the control group.</p><p><b>RESULTS</b>The lead concentrations in the three pregnancy trimesters and in the postpartum period were: (5.98 ± 2.43), (5.54 ± 2.01), (5.59 ± 1.97), and (6.76 ± 1.74) µg/dl; and (6.75 ± 2.13) µg/dl in the control group. The cadmium concentrations in the three pregnancy trimesters and postpartum period were 1.61 ± 0.45, 1.63 ± 0.46, 1.64 ± 0.49, and 1.67 ± 0.57. We found that the BLLs in the gravida group were lower than in the control group during all three trimesters. Occupations, supplement nutritional elements (dietary supplements and nutritional (food) elements), and the time of house painting could affect BLLs in pregnant women. Lead-related occupations, using cosmetics, and living in a house painted more recently than one year previously are risk factors of high BLLs among pregnant women, while calcium, iron, zinc, and milk supplements are protective factors.</p><p><b>CONCLUSIONS</b>These findings may help people, especially pregnant women, to reduce lead exposure via supplements of calcium, iron, zinc, and milk or avoiding contacting risk factors.</p>