Neurotoxicity and Biomarkers of Lead Exposure: a Review

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,Parkinson’s 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.

Effects of propranolol or propranolol plus isosorbide-5-mononitrate on variceal pressure in schistosomiasis

AIM: To compare the effects of propranolol (PR) to that of PR plus isosorbide-5-mononitrate (ISMN) on variceal pressure in patients with schistosomiasis. METHODS: Forty-eight patients with schistosomiasis who had no previous variceal bleeding were treated with PR alone or PR plus ISMN. Seven patients refused variceal pressure manometry (3 receiving PR and 4 receiving PR plus ISMN). One patient withdrew from the trial due to headache after taking ISMN. At the time of termination, twenty patients were randomly assigned to treatment with PR plus ISMN or PR alone. The dose of PR was adjusted until the resting heart rate had been reduced by 25% or was less than 55 bpm. In the PR plus ISMN group, after PR was titrated to the same target, the dose of ISMN was increased up to 20 mg orally twice a day. Variceal pressure was measured using a noninvasive endoscopic balloon technique at the end of the 6-mo treatment period. RESULTS: In 40 patients (20 in the PR group and 20 in the PR plus ISMN group), variceal pressure was measured before treatment and at the end of the 6-mo treatment period. PR or PR plus ISMN treatment caused a significant reduction in variceal pressure (PR group: from 24.15 ± 6.05 mmHg to 22.68 ± 5.70 mmHg, P = 0.001; PR plus ISMN group: from 25.69 ± 5.26 mmHg to 20.48 ± 5.43 mmHg; P < 0.001). The percentage decrease in variceal pressure was significant after PR plus ISMN compared with that after PR alone (15.93% ± 8.37% vs 6.05% ± 3.67%, P = 0.01). One patient in the PR plus ISMN group and two patients in the PR group had variceal bleeding during follow-up. There were no significant differences between the two groups regarding the incidence of variceal bleeding. In the PR plus ISMN group, three patients had headache and hypotension. The headache was mild and transient and promptly disappeared after continuation of the relevant drug in two patients. Only one patient withdrew from the trial due to severe and lasting headache after taking ISMN. No side effects occurred in the PR group. CONCLUSION: PR plus ISMN therapy may be an alternative treatment for patients with schistosomiasis who have a high risk of bleeding.

Breast Milk Lead and Cadmium Levels in Suburban Areas of Nanjing,China

Objective 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).Methods 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.Results 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.Conclusion Considering the high levels of Pb and Cd in breast milk in this study,breast milk monitoring programs are necessary.

Blood Lead Levels During Pregnancy and Its Influencing Factors in Nanjing,China

Objective 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. Methods 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. Results 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 μ/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. Conclusion Supplementing calcium, iron, zinc, and milk, or avoiding contact with risk factors may help people, especially pregnant women, to reduce lead exposure.