Delayed presentation of pacemaker Reel Syndrome and lead damage: Coincidence or consequence?

Reel syndrome is a pacemaker lead early dislodgment, characterized by reeling-in of the lead(s) without being damaged. We herein present a case of an 86-year-old woman, with medical history of single chamber pacemaker implantation two years ago, admitted in cardiology department with complete AV block. Chest-Xray revealed ventricular lead coiling around and behind the pacemaker device. Urgent extraction of the previous pacemaker was performed; however, the lead damage made its repositioning unfeasible. Successful implantation of single-chamber pacemaker has been made. This clinical case highlights the importance of adequate follow-up to timely identify lead dislodgement, avoid lethal complications and lead fracture.     

Overcoming a subclavian complete occlusion: Simple single lead extraction by the subclavian vein allowing implantation of two new leads and upgrade to CRT-P with multi-site pacing

Central venous obstruction following pacemaker implantation is not uncommon, and can prove challenging in the case of system upgrade. We report a case of DDDR to CRT-P (with multi-site pacing) upgrade, where a subclavian occlusion was overcome resorting to an atrial lead extraction (using only a locking stylet). This allowed regaining of the venous access with subsequent implantation of not just one, but two new leads and subsequent successful upgrade.     

Use of a novel pacing mode to achieve biventricular pacing in a patient with recurrent atrial lead dislodgement after CRT-D implantation

Cardiac resynchronization therapy device (CRT-P and CRT-D) implantation has increased tremendously with increasing operator experience, eligible patients and expansion of indications. Refinements in devices and algorithms now aid physicians to improve biventricular pacing and optimize CRT. We report a case in which an interesting device program was used to achieve biventricular pacing after repeated dislodgement of the atrial lead in a patient implanted with CRT-D.     

Extensive Thrombosis Following Lead Extraction: Further Justification for Routine Post-operative Anticoagulation

Lead extraction is becoming increasingly common as indications for pacing and ICD insertion expand. Periop management varies between extraction centers, and no clinical guidelines have addressed the need for perioperative anticoagulation. We report a case of massive thrombosis which occurred shortly after laser lead extraction and is undoubtedly related to the trauma of the extraction and ensuing hypercoagulabiilty. Routine post-operative anticoagulation has been advocated as a means to prevent access vein (subclavian) stenosis, but many centres do not employ a routine post-extraction anticoagulation strategy. Pulmonary embolism following lead extraction is a known complication of this procedure and late mortality following lead extraction is a significant and underappreciated problem. We propose that further research attention should be directed at addressing the issue of routine post-extraction anticoagulation.     

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.     

Exposure to lead increases the risk of meningioma and brain cancer: A meta-analysis

ObjectiveTo analyze the relationship between environmental lead exposure and various types of brain tumors.MethodsSearch databases PubMed, Web of Science, Embase and Chinese National Knowledge Infrastructure (CNKI) as of July 1, 2019. Stata 15.0 software was used for analysis.ResultsIn the case control, lead exposure was associated with gliomas and meningiomas 0.82 (95 % CI: 0.69, 0.95) and 1.06 (95 % CI: 0.65, 1.46). In the cohort study, lead exposure was associated with brain cancer and meningiomas 1.07 (95 % CI: 0.95, 1.19) and 1.06 (95 % CI: 0.94, 1.17). The risk of childhood brain tumors associated with parental lead exposure was 1.17 (95 % CI: 0.99, 1.34).ConclusionsLead may be a risk factor for meningiomas and brain cancers. However, the glioma results suggest that lead may be a protective factor, which needs to be further studied.     

An early- and late-stage convolution model for disease natural history

The standard convolution model of disease natural history posits an asymptomatic (preclinical) and a symptomatic (clinical) state. An augmented model includes, in both the preclinical and clinical states, an early and late stage of disease. In the case of cancer, the early stage would generally correspond to the organ-confined stages before there is evidence of cancer spread. We compute the number of screen-detected (preclinical) and clinical cases in the early and late stages expected under a given screening program and show how the model can be fit to data from a screening trial using maximum likelihood. We also develop expressions for sojourn time, lead time, and overdiagnosis in the context of the model, where each of the above concepts incorporates disease stage. As an example, we fit the model to data from the Mayo Lung Cancer Screening trial.     

The effect of industrial pollution on copper,lead, zinc and cadmium concentration in xylem rings of resistant (Populus marilandica) and sensitive (P. balsamifera) species of poplar

Summary The patterns of radial distribution of copper, lead, zinc and cadmium in two species of poplar, growing under polluted conditions near a copper smelter, were investigated. Populus marilandica is very resistant to such pollution, but P. balsamifera is sensitive. Soils were examined for concentrations of these metals, and only a surface layer of soil was polluted with copper and lead. P. balsamifera absorbed much more cadmium than P. marilandica under the same conditions. P. marilandica shows a pattern of copper radial distribution with significantly increased concentration of the meral in the layers in the middle of the trunk compared to P. balsamifera. Zinc and cadmium have a pattern with increased metal concentration from the bark towards the pith of the tree. In the case of copper and lead the pattern indicates increased concentrations of these metals in the rings adjacent to the pith while the pattern in other parts of the tree remains unconfirmed due to poor precision. Poplar xylem seems to accumulate zinc and cadmium while the content of lead in xylem is much lower than in the adjacent soil.This paper is dedicated to the memory of Professor Stefan Bialobok, Institute of Dendrology, Polish Academy of Sciences in Kornik     

Identification of heavy metal complexes of a hexapeptide inhibitor of the human immunodeficiency virus integrase protein by using a voltammetric approach

Complexation of the hexapeptide Hys-Cys-Lys-Phe-Trp-Trp, inhibitor of the human immunodeficiency virus integrase protein, with the heavy metal ions Cd2+, Pb2+, and Zn2+ has been investigated using differential pulse polarography. In the case of Pb2+, no significant complexation is detected, whereas in the cases of Cd2+ and Zn2+, strong and electrochemically inert ML2 complexes predominate. In contrast, ML complexes are present in a low proportion or are absent. When possible, the corresponding conditional stability constants have been determined at both pH 7.0 and pH 7.5, showing that Zn2+ complexes are slightly more stable than Cd2+ complexes.     

Lead resistance and sensitivity in Staphylococcus aureus

Abstract Five lead-resistant strains of Staphylococcus aureus were isolated. Plasmid-free lead-sensitive variants were obtained from the three plasmid-bearing strains. Lead-resistant strains tolerated an approximately 600 × higher Pb(NO₃)₂ concentration than lead-sensitive strains. Both types of strains initially bound lead, but only the resistant strains accumulated the metal as an intracellular lead-phosphate.     

The blood lead levels of outpatients aged 1–18 years from Lu’an,China, 2012–2014

To evaluate blood lead levels (BLLs) and possible influencing factors among children and adolescents in Lu’an, we collected blood samples of 3266 outpatients aged 1–18 years from January 2012 to December 2014 and BLLs were determined by atomizer absorption spectrophotometer. The results showed that the geometric mean (GM) of BLLs was 29.53 μg/L (95% CI: 29.00–30.06 μg/L) and the prevalence of BLLs ≥50 and 100 μg/L were 17.7% and 0.2%, respectively. The GM BLLs and prevalence of BLLs ≥50 μg/L were increased with age before 7 years old and then slightly decreased, and, contrary to previous studies, they were the highest at Jan–Feb and the lowest at Sep–Oct. From 2012 to 2014, the GM BLLs were significantly increased (P < 0.001) while the prevalence of BLLs ≥50 μg/L was decreased but with no significant difference (P > 0.05). These results suggested that although the BLLs of Lu’an children were lower than most areas of China and several neighboring cities as previously reported, they were still higher than that of developed countries. Meanwhile, the GM BLLs of children and adolescents from Lu’an have a trend of increase in recent years. A lot of future works need to be done to identify the risk factors for lead exposure.     

Ameliorative effects of l-carnitine on rats raised on a diet supplemented with lead acetate

Lead intoxication has been a major health hazard in humans. It affects people at all ages. Its toxicity is associated with various organs of the body and affects different metabolic pathways. Based on histological data, l-carnitine reduced the severity of tissue damage produced as a result of exposure of rats to lead acetate. The main objective of this study was to evaluate the underlying mechanism of protection offered by l-carnitine against lead acetate intoxication using male Sprague–Dawley rats.Forty male Sprague–Dawley rats were randomly divided into four groups with ten rats in each. The first group (G1) served as the control group and animals received standard diet only. The second group (G2) received lead acetate in their diet. The third group (G3) was the l-carnitine treated group and received the normal standard diet supplemented with l-carnitine. While the fourth group (G4) had a diet supplemented with both lead acetate and l-carnitine. At the end of each experiment, blood (serum and whole blood) were collected from each animal and analyzed for the following parameters: serum testosterone levels, serum nitric oxide and serum malondialdehyde. This is in addition to looking at the enzymatic activities of two important enzymes (superoxide dismutase and catalase) and on (glutathione reductase) which are indicative of the antioxidant activities in the whole blood. The results indicated that l-carnitine will counteract the undesirable effects of lead intoxication. It exerted its antioxidant potential by reducing the production of ROS and scavenging free radicals by maintaining and protecting the level of the of antioxidant enzymes SOD, CAT and glutathione peroxidase.Conclusion:l-Carnitine may play an important role in reversing the undesirable effects of lead intoxication. Future studies should be conducted to see whether such an effect is applicable in humans exposed to lead poising.     

The effect of soil type and degree of metal contamination upon uptake of Cd,Pb and Cu in bush beans (Phaseolus vulgaris L.)

Summary Five soils of increasing specific surface area (SSA) were loaded to five levels of contamination with Cd, Pb and Cu, and bean plants (Phaseolus vulgaris L.) were grown on the soils for 30 days. A linear correlation was found between the concentration of Cd in the soil solutions and the amount absorbed by the plant per gram root material for four out of the five soils, and, in the case of Cu, for all five soils. Quantitatively, there was insufficient Cd or Cu in the soil solution to account for plant uptake of these metals. The amount of Cd absorbed by plants could also be related to the adsorption density (concentration/SSA soil) of the metal in four of the five soils, whereas the Cu content of plants could be related to the adsorption density of all five soils. It is thought that the metals were removed from the soil solution by root absorption and replenished by metal cations adsorbed onto surface sites in the soil. Consideration of the adsorption density of these metals in the soil may be a useful means to determine the permissible limits for heavy metal application for a wide range of soils. Lead uptake was significantly correlated to total Pb in soils, but not to the adsorption density or soil solution concentrations. The possible interpretation of the results are discussed.     

Speciation of ionic alkyllead compounds in human urine by gas chromatography–mass spectrometry after butylation through a Grignard reaction

One analytical procedure for the determination of ionic alkyllead in human urine has been studied. The system consists of the extraction of Me₃Pb⁺, Et₃Pb⁺ and Pb²⁺ at pH 9.0 with diethyldithiocarbamate to an organic phase. Then, the ionic compounds are butylated with BuMgCl and the final organic solution is analyzed by GC–MS–SIM. The elimination of both foam and gels in the extraction step and the general procedure for the urine are discussed. The recovery of compounds ranges from 105.1% for Me₃Pb⁺ to 97.2% for Et₃Pb⁺ using hexane as extracting agent and detection limits are 18.4 pg/ml of Me₃Pb⁺ and 19.2 pg/ml of Et₃Pb⁺ in urine. The speciation of ionic alkylleads in the urine of a petrol station worker showed a value of 27.9 pg/ml of Me₃Pb⁺ in urine and Et₃Pb⁺ was below the detection limit.     

An Estimate of the Variance of Estimators for Lead Time and Screening Benefit Time in Randomized Cancer Screening Trials

Variance estimators are derived for estimators of the average lead time and average benefit time due to screening in a randomized screening trial via influence functions. The influence functions demonstrate that these estimators are asymptotically equivalent to the mean difference, between the study and control case groups, in the appropriate survival times. For estimating benefit time, the survival time is measured since start of study; for estimating lead time, the survival time is measured since time of diagnosis. Asymptotic variances of these estimators can be calculated in a straightforward manner from the influence functions, and these variances can be estimated from actual trial data. The performance of the variance estimators is assessed via a simulated screening trial. The situation involving censored data is also discussed.     

Cardiovascular implantable electronic device lead removal in a resource-constrained setting: A single-center experience from India

BackgroundData from large-volume centers in developed countries, using dedicated tools, show a high success rate with a good safety record for the percutaneous lead removal procedure. However, there are constraints to replicate the results in a resource-poor setting and there is limited data from India.MethodsWe retrospectively analyzed lead removal procedures performed in our institution from 2008 to 2019.ResultsSeventy-five patients underwent percutaneous removal of 138 leads. Of these, 44 procedures and 80 leads qualified as extraction with a median dwell time of 52.1 (IQR 28.2–117.2) months. Overall, 33/44 (75.0%) procedures were successful and 65/80 (81.2%) leads were successfully extracted. Manual traction was successful in the extraction of 44/57 (77.2%) leads. All leads implanted less than 2.7 years could be removed with manual traction alone. Specialized tools were used in 23 leads and 21 (91.3%) of those could be successfully extracted. Inability to use dedicated tools was an independent predictor of procedural failure (adjusted OR 14.0; 95% CI 1.8–110.2; p-value 0.012). Right-sided implant (adjusted OR 12.6; 95% CI 1.3–119.5; p-value 0.027) was also independently associated with failure. There was 1 death (1.3%) and minor complications occurred in 6 (8.0%) patients.ConclusionsIn a resource-limited setting, percutaneous lead extraction of predominantly pacemaker leads by manual traction methods achieved success in extracting about three-fourths of the leads. Inability to use specialized tools was the main factor limiting success. The complication rate was low.     

Normal pacing function with normal impedance trends despite evident lead fracture in an implantable defibrillator – What is the mechanism?

A 63-year-old lady with a high-grade atrioventricular (AV) block and a structurally normal heart underwent permanent pacemaker implantation (dual chamber, Medtronic Ltd) 8 years back. On follow up, she had a recurrence of syncope after 3 years. The device interrogation at that time had revealed ventricular tachycardia (VT) for which she underwent implantable cardioverter defibrillator (ICD, Medtronic Ltd, Egida DR, DF1) upgradation at another center (electrograms not available). Now, she presents with episodes of presyncope after another 5 years. The Echocardiography was unremarkable. The ICD was interrogated & there was a stored ventricular fibrillation (VF) episode. But the electrograms suggested noise over a true VF electrogram noted in both near and far-field. In all probability, the VF was not a true one which might have arisen from some lead noise or from an electromagnetic interference (EMI). Fluoroscopy revealed an evident lead fracture near the superior vena cava (SVC) coil. The stored electrogram (EGM) characteristics also suggested possible lead noise rather than a true VF. She was advised for lead revision. Interestingly, all pacing parameters were normal along with normal impedance despite the evident lead fracture. This happened due to the ICD lead arrangements as there are separate electrodes for the SVC/RV coil and pacing. While the SVC coil was damaged, the pacing electrodes remained unaffected. Since the patient has no episode of true VT/NSVT and the echocardiography was normal, she was managed temporarily by changing the pacemaker to asynchronous (DOO) mode.     

Postmortem absorption of lead by the skeleton

In a study of bones recovered from lead coffins at two sites in the United Kingdom, the lead concentration was so high that postmortem absorption seemed the most likely explanation. Electron probe analysis showed that in one bone from a lead coffin, the lead was concentrated on the surfaces of the bone, as would be expected if absorption had occurred after death. It is suggested that in any further study of the lead content of bones from archaeological sites, steps must be taken to assess environmental lead levels and if these are unusually high, the results of the analyses should be viewed with suspicion.     

Relationship between lead absorption and iron status and its association with oxidative stress markers in lead-exposed workers

BackgroundThe emission of lead (Pb) occurring during the extraction, processing and industrial applications of this element remains a significant environmental risk factor. The absorbability of lead in humans is strongly associated with the general health status of exposed individuals. Existing mineral deficiencies are considered being a predisposition to an increased Pb uptake. Both, iron deficiency and lead poisoning are the major causative factors responsible for the prevalence of anemia within the vulnerable population, especially in children. Although some of the intervention programs of counteracting lead poisoning by iron supplementation proved to be effective in the Pb-exposed population, the exact mechanisms of this interaction still require further studies. The objective of the presented study was to examine the association of iron level on oxidative stress measures and its effects on the severity of lead toxicity in the exposed population.MethodsThe analyzed population consisted of 270 male workers from the lead-zinc smelter. The studied population was divided into two sub-groups based on the serum iron concentration: low iron level group (L-Fe; Fe < median value) and high iron level group (H-Fe; Fe > median value). Measured traits comprised of blood lead (PbB), serum Fe and zinc protoporphyrin (ZPP) levels as well as a blood count and oxidative stress markers.ResultsNo significant correlation between serum iron concentration and PbB in the tested cohort was found. On the contrary, the analysis of ZPP levels (long-term marker related to a hematologic toxic effect of Pb) within the subgroups differing in serum Fe level shown that ZPP was 12.3 % lower (p = 0.043) in subjects classified within the H-Fe group. A positive correlation of serum Fe and total antioxidant capacity (TAC) was found (R = 0.1999). The conducted 3-D PCA analysis showed that individuals classified within the H-Fe group were characterized by the co-occurrence of higher Fe levels, lower ZPP, and higher TAC value.ConclusionThese results support the existing evidence providing that maintaining the optimal status of Fe may play a significant role in preventing the lead poisoning and alleviating harmful effects of Pb on the oxidative balance in humans.     

Ultrastructural effects on gill tissues induced in red tilapia Oreochromis sp. by a waterborne lead exposure

Experiments on hybrid red tilapia Oreochromis sp. were conducted to assess histopathological effects induced in gill tissues of 96 h exposure to waterborne lead (5.5 mg/L). These tissues were investigated by light and scanning electron microscopy. Results showed that structural design of gill tissues was noticeably disrupted. Major symptoms were changes of epithelial cells, fusion in adjacent secondary lamellae, hypertrophy and hyperplasia of chloride cells and coagulate necrosis in pavement cells with disappearance of its microridges. Electron microscopic X-ray microanalysis of fish gills exposed to sublethal lead revealed that lead accumulated on the surface of the gill lamella. This study confirmed that lead exposure incited a difference of histological impairment in fish, supporting environmental watch over aquatic systems when polluted by lead.