Chronic Lead Research Articles

D-serine reduces memory impairment and neuronal damage induced by chronic lead exposure.

Although exogenous D-serine has been applied as a neural regulatory intervention in many studies, the role played by D-serine in hippocampal injuries caused by lead exposure remains poorly understood. Rat models of chronic lead exposure were established through the administration of 0.05% lead acetate for 8 weeks. Simultaneously, rats were administered 30 or 60 mg/kg D-serine, intraperitoneally, twice a day. Our results showed that D-serine treatment shortened the escape latency from the Morris water maze, increased the number of times that mice crossed the original platform location, and alleviated the pathological damage experienced by hippocampal neurons in response to lead exposure. Although D-serine administration did not increase the expression levels of the N-methyl-D-aspartate receptor subtype 2B (NR2B) in the hippocampi of lead-exposed rats, 60 mg/kg D-serine treatment restored the expression levels of NR2A, which are reduced by lead exposure. These findings suggested that D-serine can alleviate learning and memory impairments induced by lead exposure and that the underlying mechanism is associated with the increased expression of NR2A in the hippocampus. This study was approved by the Animal Ethics Committee of North China University of Science and Technology, China (approval No. LX2018155) on December 21, 2018.

The Effects of Calcium Supplementation on Blood Lead Levels and Short-term Memory of Chronically Exposed Children: A Clinical Trial Study

AIM: The purpose of this study is to determine the effects of calcium supplementation to decrease blood lead levels (BLLs) of children at high risk for chronic lead poisoning and to determine its effects on short-term memory.
 MATERIALS AND METHODS: Children aged 8–12 years lived in the highest traffic density in Medan randomly included in this quasi-experimental study, divided into two groups (control and supplementation group received tablet contain four hundred milligrams oral calcium twice daily for 3 months). Samples for BLLs were collected before and after 3 months of supplementation, and short-term memory measurements are carried out by picture and forward digital span test. Descriptive statistics were calculated at baseline and 3 months; comparison between before and after treatment was assessed with t-tests, p < 0.05 considered statistically significant.
 RESULTS: BLLs samples, who are exposed to lead for >6 months were ranging between 0.4–12 μg/dL. Median BLLs in supplementation group before treatment was 2.1 μg/dL and after treatment was 0.01 μg/dL (p < 0.01); difference between median in BLLs after treatment in supplementation group was 2.090 μg/dL (p = 0.004). Score memory picture in the supplementation group before treatment was 61.4 ± 24.83 and after treatment was 76.21 ± 15.97 (p<0.01). Score memory digital span in the supplementation group before treatment was 5 (3–7) and after treatment was 7 (5–7) (p < 0.01).
 CONCLUSION: Three months of oral calcium supplementation 400 mg twice daily for high-risk chronic lead poisoning children reduced BLLs significantly and improved their short-term memory.

Impact of Lead Exposure on Thyroid Status and IQ Performance among School-age Children Living Nearby a Lead-Zinc Mine in China

BackgroundLead exposure is one of the most concerning public health problems worldwide, particularly among children. Yet the impact of chronic lead exposure on the thyroid status and related intelligence quotient performance among school-age children remained elusive. ObjectiveThe aim of this study was to evaluate the influence of lead exposure on the thyroid hormones, amino acid neurotransmitters balances, and intelligence quotient (IQ) among school-age children living nearby a lead-zinc mining site. Other factors such as rice lead levels, mothers’ smoking behavior, and diet intake were also investigated. MethodsA total of 255 children aged 7-12 years old were recruited in this study. Blood lead level (BLL), thyroid hormones including free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH), and amino acid neurotransmitters such as glutamate (Glu), glutamine (Gln), and γ-aminobutyric acid (GABA) were measured using graphite furnace atomic absorption spectroscopy (GFAAS), chemiluminescence immunoassay, high performance liquid chromatography (HPLC). Raven's standard progressive matrices (SPM) and the questionnaire were used to determine IQ and collect related influence factors. ResultsThe average BLL of children was 84.8 μg/L. The occurrence of lead intoxication (defined as the BLL ≥ 100 μg/L) was 31.8%. Serum TSH levels and IQ of lead-intoxicated children were significantly lower than those without lead toxicity. The GABA level of girls with the lead intoxication was higher than those with no lead-exposed group. Correlation analyses revealed that BLL were inversely associated with the serum TSH levels (R= -0.186, p < 0.05), but positively related with IQ grades (R = 0.147, p < 0.05). Moreover, BLL and Glu were inversely correlated with IQ. In addition, this study revealed four factors that may contribute to the incidence of lead intoxication among children, including the frequency of mother smoking (OR = 3.587, p < 0.05) and drinking un-boiled stagnant tap water (OR = 3.716, p < 0.05); eating fresh fruits and vegetables (OR = 0.323, p < 0.05) and soy products regularly (OR = 0.181, p < 0.05) may protect against lead intoxication. ConclusionLead exposure affects the serum TSH, GABA levels and IQ of school-aged children. Developing good living habits, improving environment, increasing the intake of high-quality protein and fresh vegetable and fruit may improve the condition of lead intoxication.

Chronic lead poisoning induced abdominal pain and anemia: a case report and review of the literature

BackgroundChronic lead poisoning (CLP) is a rare cause of abdominal pain and is common in young children, in whom the incidence is higher than it is in adults. As the symptoms of CLP are nonspecific, misdiagnoses or missed diagnoses often occur, especially in sporadic cases.Case presentationWe report a 28-year-old young man who was misdiagnosed with renal colic due to sudden acute abdominal pain. After a detailed medical history and physical examination, other possible causes were excluded, CLP was finally diagnosed, and he recovered after chelation treatment.ConclusionAbdominal pain is a very common clinical symptom in adults, which has many causes. We should be vigilant against chronic poisoning, especially CLP. Detailed diagnosis and physical examination are crucial in early diagnosis and treatment.

Hematological and cardiovascular effects of chronic low level lead exposure: A study on e-waste recyclers

BackgroundChronic exposure to lead is detrimental, despite exposed to very low levels. Hematological and cardiovascular system are among the commonly affected systems due to chronic lead exposure. With tremendous progressive usage electrical and electronic products, they are being scrapped, recycled and refurbished by process of e-waste recycling. Primitive e-waste recycling activities are increasingly popular and contributes substantially to the economy and employment. However, the e-waste recycling process is a source of occupational lead exposure. ObjectiveTo evaluate the influence of chronic lead exposure on the hematological and cardiovascular parameters among e-waste recyclers with variable levels of lead exposure. MethodologyAll workers from two e-waste recycling units with significantly different lead levels were recruited after informed consent. Socio-demographic, occupational and clinical details of all participants were recorded. Environmental and blood lead levels (BLL) were evaluated using graphite furnace atomic absorption spectroscopy (GF-AAS). The hematological parameters and cardiovascular parameters were assessed using standard tools. Group differences and multivariate regression analysis to achieve the objectives was performed using Statistical Package for Social Science version 17.0. ResultsSixty-four Workers employed (32 from each recycling unit) in these recycling units were exposed to significantly different levels of lead, however the levels were well within the permissible limits. Workers exposed to higher environmental lead levels had significantly higher BLL & diastolic blood pressure (DBP) as compared to their comparators. Further, workers with higher BLL exhibited a trend of reduced hemoglobin as compared to the workers with lower BLL. However, the study observed a trend of changes (hematological & cardiovascular) consistent to the possible homeostasis mechanisms of reduced hemoglobin. Elevation in blood pressure (BP), a known compensatory response to peripheral hypoxia (due to reduced hemoglobin), observed in the current study could either be due to direct and indirect (reduced hemoglobin) influence of lead exposure. ConclusionIndividuals chronically exposed to Lead, despite within the permissible levels can exhibit detrimental effects. Present results indicate the direct and indirect (reducing hemoglobin) mechanisms by which lead would influence BP. Future studies are recommended to confirm the present results.

S2982 Incidental Gastric Cancer: How a Routine Evaluation of Chronic Liver-Associated Enzyme Elevation Lead to the Discovery of Two Synchronous Gastric Cancers in an Asymptomatic Patient

S2982 Incidental Gastric Cancer: How a Routine Evaluation of Chronic Liver-Associated Enzyme Elevation Lead to the Discovery of Two Synchronous Gastric Cancers in an Asymptomatic Patient

Beneficial effect of Mentha spicata essential oil on lead and manganese induced nephrotoxicity and oxidative damage in rat kidney

Our work focused on the impact of chronic lead acetate and manganese chloride poisoning on renal function in Wistar rats. It also tested the efficacy of the essential oil extracted from (Mentha spicata) spearmint in reversing these effects by treating previously poisoned rats with a daily intraperitoneal injection of 0.1 ml HEM/kg over a 21-days period. Analysis of this essential oil through gas chromatography coupled with mass spectrometry revealed that the main components are: carvone (42.2%), menthone (20.89%), piperitenone (17.41%) and isomenthone (7.99%). Chronic oral co-exposure to lead and manganese during periods of gestation and lactation resulted in a significant reduction (P&lt;0.01) in both body and kidney weight. Further examination of renal function revealed significant disturbances in the quantity of markers of renal function (creatinine, urea, uric acid) in the blood. Chronic co-exposure led to the observation of disruption to antioxidant enzyme (superoxide dismutase, glutathione peroxidase and catalase) activity in poisoned rats in comparison with the control rats; these results suggest renal failure. Indeed, histological study of the kidneys revealed pronounced damage manifesting as cell degeneration with the renal parenchyma affected by inflammation. In addition, the administration of the essential oil of Mentha spicata led to the observation of an increase in body weight, regulation of the various biochemical markers, and the regeneration of damaged renal tissue, all of which proves the high importance of spearmint in traditional medicine, and its therapeutic properties in combating renal problems.

Evaluation of chronic lead effects in the blood brain barrier system by DCE-CT

BackgroundLead (Pb) is an environmental factor has been suspected of contributing to the dementia including Alzheimer’s disease (AD). Our previous studies have shown that Pb exposure at the subtoxic dose increased brain levels of beta-amyloid (Aβ) and amyloid plaques, a pathological hallmark for AD, in amyloid precursor protein (APP) transgenic mice, and is hypothesized to inhibit Aβ clearance in the blood- cerebrospinal fluid (CSF) barrier. However, it remains unclear how different levels of Pb affect Aβ clearance in the whole blood-brain barrier system. This study was designed to investigate whether chronic exposure of Pb affected the permeability of the blood-brain barrier system by using the Dynamic Contrast-Enhanced Computerized Tomography (DCE-CT) method. MethodsDEC-CT was used to investigate whether chronic exposure of toxic Pb affected the permeability of the real-time blood brain barrier system. ResultsData showed that Pb exposure increased permeability surface area product, and also significantly induced brain perfusion. However, Pb exposure did not alter extracellular volumes or fractional blood volumes of mouse brain. ConclusionOur data suggest that Pb exposure at subtoxic and toxic levels directly targets the brain vasculature and damages the blood brain barrier system.

The effects of chronic lead exposure on the ovaries of female juvenile Japanese quails (Coturnix japonica): Developmental delay, histopathological alterations, hormone release disruption and gene expression disorder

Lead (Pb) is well-recognized for its great hazards to human and wildlife health. It has negative influences on multiple organs and systems of birds. Especially, lead exposure caused adverse impacts on bird reproduction. In this study, one week old female Japanese quails were randomly allocated into four groups and each group was respectively fed with 0, 50 ppm, 500 ppm and 1000 ppm Pb in drinking water for 36 days to determine the effects of chronic lead exposure on ovarian development and function. The results showed that Pb did accumulate in the ovary and ovarian development was delayed by high dose lead exposure (500 ppm and 1000 ppm). Moreover, high Pb dosage induced ovarian histopathological damages characterized by granulosa cells disorganization, follicle atresia and interstitial cell degeneration. Meanwhile, the concentration of estradiol (E2) was significantly decreased and mRNA levels of genes involved with ovarian steroidogenesis were significantly down-regulated by high concentration Pb. In addition, Pb exposure caused increasing cell apoptosis and significant changes of the expression of genes involved with cell death in the ovary. High dose Pb exposure also inhibited thyroid hormone release and disrupted ovarian thyroid deiodination apart from causing thyroid histopathological injury such as follicular deformation and atrophy. The study indicated that Pb might cause ovarian malfunction by inducing ovary and thyroid microstructural damages, thyroid hormone and estrogen release inhibition and ovarian steroidogenesis disruption.

Long-term performance of left ventricular leads in cardiac resynchronisation therapy.

Cardiac resynchronisation therapy (CRT) confers symptomatic and survival benefits in chronic heart failure with reduced ejection fraction (HFrEF). There remains a paucity of data on long-term performance of left ventricular (LV) leads, particularly with newer quadripolar lead designs. This single-centre study utilised an electronic, outpatient HFrEF database to identify CRT recipients (2008-2014). The primary endpoint was temporal trend in LV pacing thresholds during follow-up. Secondary outcomes were complications relating to acute or chronic lead failure and device-related infections. Two hundred eighty patients were included, with mean (±SD) age of 74.2 years (±9.0) and median follow-up of 7.6 years (interquartile range 4-9). Mean LV threshold was 1.37 V (±0.73) at implant and remained stable over the study period. No differences were observed based upon lead manufacturer. Compared to non-quadripolar leads (n=216), those of quadripolar designs (n=64) had a lower threshold at 6 months (1.20 vs 1.37 V; P=.04) and at the end of the study period (1.32 vs 1.46 V; P=.04). Patients with HFrEF of ischaemic aetiology had higher thresholds at implant (1.46 vs 1.34 V; P=.05), and this persisted until the end of follow-up (1.49 vs 1.34 V; P=.03). There was low incidence of acute (0.71%; 2/280) and chronic lead failure (1.79%; 5/280), with four cases (1.43%) of device infection. LV leads in the context of CRT have excellent chronic stability and low rates of adverse events. Those with newer quadripolar lead designs have lower thresholds at initial follow-up and in the longer term.

Lead exposure in the home environment: An overview of risks from cottage industries in Africa

• Acute and chronic lead exposures from cottage industries in Africa are highlighted. • Lead poisoning outbreaks at community and household level are described. • Health and safety regulations for those working in cottage industries is required.

Changes in inflammatory cytokines, antioxidants and liver stiffness after chelation therapy in individuals with chronic lead poisoning

BackgroundChronic exposure to lead causes lead to accumulate mainly in the liver. In vivo studies have shown that lead toxicity is related to alterations in the inflammatory response. We aimed to evaluate the association between lead poisoning and liver fibrosis as well as the change in the degree of liver fibrosis, levels of inflammatory mediators and glutathione (GSH) after chelation therapy.MethodsWorkers from a battery factory who were exposed to lead for > 12 months and had a blood lead level (BLL) > 70 μg/dL were enrolled (n = 86) in the study. Participants underwent chelation therapy with intravenous CaNa2EDTA for 2 days followed by treatment with oral D-penicillamine for 90 days. The primary outcome was the change in the degree of liver fibrosis, which was presented as liver stiffness (LS) measured by FibroScan®. Secondary outcomes were the changes in the levels of serum GSH and inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) after chelation therapy.ResultsAmong the 86 participants, there was a positive correlation between the duration of lead exposure and LS (r = 0.249, p = 0.021). To avoid the confounding effect of obesity-related steatosis, only 70 individuals who had controlled attenuation parameters < 296 dB/m, BMI < 25 kg/m2 and normal waist circumference were included in the interventional analysis. After chelation, the mean LS significantly decreased from 5.4 ± 0.9 to 4.8 ± 1.4 kPa (p = 0.001). Similarly, all of the inflammatory cytokines studied significantly decreased after chelation (p < 0.001); TNF-α decreased from 371.6 ± 211.3 to 215.8 ± 142.7; the levels of IL-1β decreased from 29.8 ± 1.7 to 25.9 ± 4.3; and the levels of IL-6 decreased from 46.8 ± 10.2 to 35.0 ± 11.9. On the other hand, the mean GSH level increased significantly from 3.3 ± 3.3 to 13.1 ± 3.7 (p < 0.001) after chelation therapy.ConclusionThe duration of lead exposure was significantly correlated with the degree of liver fibrosis. Chelation treatment was associated with increased levels of GSH and decreased levels of proinflammatory cytokines and could potentially reduce the degree of LS.Trial registrationThis study was retrospectively registered and approved by the Thai Clinical Trial Registry (TCTR) on 2019-11-07. The TCTR identification number is TCTR20191108001.

Identification of the origin of infantile saturnism based on lead isotopic and elemental ratios

BackgroundIn France, the prevalence of childhood lead poisoning is becoming rare since the avoidance of lead in paints in 1949 and the gradual replacement of water pipes. Chronic lead toxicity is well known and is well correlated to blood lead concentration. AimHere we report a case of severe lead poisoning occurring in a young female child with a pica behavior. MethodsA blood sample and four environmental samples were analyzed using inductively coupled plasma- mass spectrometry (ICP-MS). Lead concentration, lead isotopes and elemental ratios were compared. ResultsThe determination of 208Pb/206Pb, 206Pb/207Pb and Cd/Pb has allowed us to identify the origin of lead poisoning. Discussion-conclusionThe source of contamination was eliminated and the child benefited from a psychological and medical follow up. Her outcome was positive. This case illustrated the potential interest of the use of elemental and isotopic ratios for clinical practice as the ICP-MS measurement has allowed a quick response and a rapid eviction of the contamination’s source.

Effect of humic acids on lead poisoning in bones and on a subcellular level in mitochondria.

Humic acids (HA) are natural substances which exhibit a remarkable spectrum of health benefits, such as their role in chelation. This study aims to supplement the current knowledge on the chelating effects of HA in chronic lead intoxication in rat femurs and in liver, heart and kidney mitochondria in an experiment lasting 10weeks. Lead acetate trihydrate was administered to rats for 5weeks at a daily dose of 155.5mg/kg body weight. At the same time, rats were given three concentrations of HA, with their effect measured over the following 5weeks. Increased Pb concentrations were detected in the femur after the first week, while HA-administered groups showed a tendency towards inhibiting the increase in Pb deposition. After 5weeks, Pb concentrations dropped significantly in the HA groups. At the same time, however, other elements were redistributed, with a decrease in Se and Zn being particularly noteworthy. While an increase in Pb concentrations was found after 5weeks of Pb administration, a concentration of 1% HA resulted in the least significant increase in Pb as well as an increase/decrease in Se/Cu, respectively. In mitochondria, an increase in Pb content was detected after the first and fifth weeks with concomitant redistribution of other elements. At the end of the experiment, again in the 1% HA group, Pb concentrations remained higher only in the liver with the other elements sufficiently normalized, indicating this concentration to be useful in the treatment of Pb intoxication.

Epigenetic Basis of Lead-Induced Neurological Disorders.

Environmental lead (Pb) exposure is closely associated with pathogenesis of a range of neurological disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), attention deficit/hyperactivity disorder (ADHD), etc. Epigenetic machinery modulates neural development and activities, while faulty epigenetic regulation contributes to the diverse forms of CNS (central nervous system) abnormalities and diseases. As a potent epigenetic modifier, lead is thought to cause neurological disorders through modulating epigenetic mechanisms. Specifically, increasing evidence linked aberrant DNA methylations, histone modifications as well as ncRNAs (non-coding RNAs) with AD cases, among which circRNA (circular RNA) stands out as a new and promising field for association studies. In 23-year-old primates with developmental lead treatment, Zawia group discovered a variety of epigenetic changes relating to AD pathogenesis. This is a direct evidence implicating epigenetic basis in lead-induced AD animals with an entire lifespan. Additionally, some epigenetic molecules associated with AD etiology were also known to respond to chronic lead exposure in comparable disease models, indicating potentially interlaced mechanisms with respect to the studied neurotoxic and pathological events. Of note, epigenetic molecules acted via globally or selectively influencing the expression of disease-related genes. Compared to AD, the association of lead exposure with other neurological disorders were primarily supported by epidemiological survey, with fewer reports connecting epigenetic regulators with lead-induced pathogenesis. Some pharmaceuticals, such as HDAC (histone deacetylase) inhibitors and DNA methylation inhibitors, were developed to deal with CNS disease by targeting epigenetic components. Still, understandings are insufficient regarding the cause–consequence relations of epigenetic factors and neurological illness. Therefore, clear evidence should be provided in future investigations to address detailed roles of novel epigenetic factors in lead-induced neurological disorders, and efforts of developing specific epigenetic therapeutics should be appraised.

Effectiveness of hair lead concentration as biological indicator of environmental and professional exposure s

Introduction: Biological monitoring is highly recommended to assess occupational and environmental exposures to toxic chemicals. In this context, blood and urine are conventional matrices for lead poisoning biotoxicological assessment. Blood and urine analysis are more contributive for recent lead exposure. Chronic lead exposure may have different characteristics. long-term exposure could be responsible of insidious poisoning which cannot always be assessed by these usual matrices. The aim of this study is to demonstrate that human hair can be used as an alternative matrix to detect chronic toxic exposure among occupationally and non-occupationally leadexposed subjects. Material and Method: This case-control study analyzed blood, urine and hair sampled from 40 exposed workers versus a control group of 30. Particulate matters of lead are collected from different workplace ambient air. Analysis is realized using the graphite furnace atomic absorption spectrometry. Correlations are studied between the different matrices in both groups and between seniority and lead concentrations in biological samples. Results This study concerned 70 male subjects: forty battery manufacturing factory workers and thirty controls (non-exposed to lead in their workplaces). The results showed a significant correlation between lead levels in the three matrices and the intensity of exposure among both groups (Pb hair-blood P=0.017;Pb hair-urine&lt;0.000). Hair lead concentrations study among cases in function of occupational seniority confirmed the stability of this matrix (Pb&gt;3000 µg/g of hair at 20 years). The study of hair lead concentration according to workplace showed a significantly higher exposure for the station of assemblers. Conclusion Hair is an efficient biological sample to assess lead poisoning especially for chronic exposure. Hair is easy to collect, to handle and gives reproducible results that may be useful in monitoring of exposed workers. Key words Lead poisoning, monitoring, exposure, hair samples.

Lead Exposure Influences Serum Biomarkers, Hepatocyte Survival, Bone Marrow Hematopoiesis, and the Reproductive Cycle in Japanese Quails.

Lead toxicity has been a hallmark issue of toxicology over the last decades. However, predictive and non-robust models did not provide complete data on low-dose lead interaction with the organism at different functional levels (e.g., blood-serum-liver-bone marrow-bursa fabricii-reproductive system axis). Japanese quails are an animal model with a strong immune system, making them suitable for the thorough assessment of in vivo chronic lead toxicity. In this study, we have exposed Japanese quails via water ingestion to 0.25 and 0.5 μg/mL lead(II) chloride (PbCl2) for 20 days and assessed blood cells, serum biomarkers, hepatocyte survival, bone marrow hematopoiesis, bursa fabricii, and lead accumulation in eggs. Blood cells passed through morphological alterations (loss and inversion of the erythrocyte nucleus, multiple erythrocyte and thrombocyte aggregation, lymphocyte degradation, and blast cell infiltration). In the serum, PbCl2 increased the activity of creatine kinase (CK) and lactate dehydrogenase (LDH); increased the level of cholesterol, sodium, creatinine, and urea; and reduced the level of proteins, triglycerides, chloride, potassium, calcium, and alkaline phosphatase (ALP) activity (P < 0.05). Liver tissue of the exposed animals exhibited apparent death of hepatocytes. In the bone marrow, macrophages and heterophils contained a vast number of the infiltrated/uptaken granules upon PbCl2 exposure. Ultimately, PbCl2 exposure elicited a series of events observed first in the blood and serum parameters and later translated to the hematopoietic centers.

Blood lead level (BLL), δ-aminolevulinic acid dehydratase activity (ALAD), hemoglobin (Hb) and hematocrit (hct) in primary school-children and adult residents living in smelter rural areas in Kosovo

The objective of this study was to investigate the effects of chronic environmental lead (Pb) exposure in blood lead level (BLL), δ-aminolevulinic acid dehydratase (ALAD) activity, hemoglobin (Hb) amount and hematocrit (Hct) value in primary schoolchildren and adults. Blood was obtained for BLL, ALAD, Hb and Hct measurements in 23 primary schoolchildren (girls and boys) and 117 adult residents (women and men) living in three villages (Kelmend, Boletin and Zhazhë) defined by concentric circles 2, 3 and 5 km in radius drawn around from the smelter-refinery complex “Trepça”in Zveçan and in Koliq village 40 km away. As expected, BLLs were substantially higher in the schoolchildren from smelter area compared with control (11 ± 4.2 µg/L and 6.9 ± 1.6 µg/L respectively) and in adult residents from Kelmend, Boletin and Zhazhë (24 ± 11.8, 12 ± 4.5, 11 ± 5.4 and 8.0 ± 2.8 µg/L respectively). Blood ALAD activity of children in Zhazhë is 16% inhibited compared to control and blood ALAD activity in adults in villages from smelter area is 32, 3%, 48, 4% and 17, 8% inhibited compared to control. There is no difference of Hb and Hct values in schoolchildren from Zhazhë and in adult residents from Kelmend and Zhazhë compared with control. Results of this study provide evidence of moderate inverse correlation between BLL and ALAD activity in both examined cohorts from smelter area. The inhibition of ALAD activity in primary schoolchildren and adults occurred at blood lead levels < 24 µg/L; consequently it can cause an increase of δ- Aminolevulinic acid.

Leadless cardiac pacing in resource limited settings: A Groote Schuur hospital experience with the Micra leadless pacemaker

Background: Cardiac pacemakers improve survival and quality of life in patients with atrioventricular (AV) block. However, conventional pacemakers carry a small risk of both acute and chronic lead and pacemaker generator complications. Leadless pacemakers negate these risks by not having a pacing lead and a subcutaneous generator. We report our Groote Schuur Hospital experience with the Medtronic Micra transcatheter pacing system (TPS). Methods: We report a consecutive case series of patients that received the Micra leadless pacemaker. The Micra transcatheter pacemaker, a single chamber ventricular pacemaker, is inserted using a TPS via the femoral vein into the right ventricle. Implantation data were obtained, and medical records were reviewed for the 6 weeks and 1-year follow-up visits. Results: A total of 5 patients were implanted with a Micra leadless pacemaker from 11 March 2015 - 2 November 2016. Four patients were male and 1 female, with an average age of 64 years. Four patients received the pacemaker for a second- or third-degree AV block and 1 patient received the pacemaker for unexplained syncope and right bundle branch block. The Micra leadless pacemaker was successfully implanted in all patients with no acute implantationrelated complications. One-year follow-up was available for 4 patients with good pacing thresholds, sensitivity and impedance. One patient demised after 9 months post Micra implantation due to unrelated causes (acute myeloid leukaemia). Conclusion: The Micra leadless pacing system is safe and effective and shows good short-term results in a real-world, resource-limited setting. This form of pacing offers a viable option for patients who require pacing for AV block, especially in patients with vascular access problems or who are at high risk of lead or pacemaker generator complications.

Blood Magnesium Level and Selected Oxidative Stress Indices in Lead-Exposed Workers

Occupational exposure to lead is one of the important hazards to human global population. Lead interferes with divalent cations, such as calcium, magnesium, and iron. Magnesium is the fourth most common mineral in the human body and a cofactor in more than 325 enzymes. There are many disorders associated with magnesium deficiency. It has been postulated that hypomagnesemia promotes oxidative stress. Study population included 232 male employees of lead-zinc works and was divided into two sub-groups based on the median of magnesium serum level: low magnesium level (L-Mg) group and high magnesium level (H-Mg) group. Magnesium level was significantly higher in the H-Mg group than in the L-Mg group due to the study design. The level of zinc protoporphyrin was significantly higher in the L-Mg group than in the H-Mg group by 13%, while the blood lead levels were similar in the examined groups. The serum level of MDA was significantly higher in the L-Mg group than in the H-Mg group by 12%, while the serum levels of thiol groups, TAC, and bilirubin were significantly lower in that group by 6%, 3%, and 27%, respectively. Similarly, the erythrocyte SOD activity was lower in the L-Mg group than in the H-Mg group by 5%. Low serum magnesium levels contribute to lead-induced oxidative stress, result in unfavorable modification of antioxidant system function, and promote lead-induced impairment of heme synthesis. Obtained results indicate that prevention of hypomagnesemia should be regarded as an important step in ensuring adequate prophylaxis of chronic lead poisoning.