Day, Patrick

Abstract Background Kidney stones are a highly prevalent disease worldwide. Additionally, both environmental and occupational exposure to Pb and Cd continue to be prevalent globally and can result in renal toxicity. The objective of this study was to examine the potential presence of Pb and Cd in kidney stones, and to assess for correlation with demographic factors including smoking, gender, age, and kidney stone matrix composition. Methods Patient kidney stones (n = 96) were analyzed using Fourier transform infrared spectroscopy to identify the stone constituents. Cd and Pb concentrations (µg/g) were determined by inductively coupled plasma mass spectrometry. Cd and Pb concentrations were correlated using bivariable and multivariable statistical analysis with demographic factors (age, gender, smoking status), and kidney stone composition. Results Kidney stone Cd (median 0.092 µg/g, range 0.014 to 2.46) and Pb concentrations (median 0.95 µg/g, range 0.060 to 15.4) were moderately correlated (r = 0.56, P < 0.0001). Cd concentrations were positively associated with patient history of smoking, patient age, and calcium oxalate monohydrate levels while negatively associated with struvite and uric acid/uric acid dihydrate. Pb concentrations were positively associated with females and apatite levels while negatively associated with uric acid/uric acid dihydrate. After holding constant other stone type composition levels, smoking status, and age, both Pb and Cd were positively associated with apatite and negatively associated with uric acid/uric acid dihydrate, struvite, and calcium carbonate. Conclusions Cd and Pb kidney stone concentrations are associated with specific kidney stone types. Cd and Pb kidney stone concentrations are both associated with smoking.

Background Gadolinium-based contrast agents (GBCAs) have been used in magnetic resonance imaging for the past 30 years, where they have significantly improved the effectiveness of imaging studies. However, the increased usage of gadolinium in the medical community has also resulted in unexpected interferences in other laboratory assays. This has been particularly the case in clinical elemental analysis using inductively coupled plasma mass spectrometry (ICP-MS). Methods By conducting ICP-MS interference experiments, we describe how gadolinium interferes with elemental analysis by space charge effect, double charge effect and the creation of polyatomic interferences. Additionally, by reviewing more than a year of reference laboratory data from our laboratory information system, we determined the number of elemental tests cancelled due to gadolinium interference. Results Interference experiments show that gadolinium normally found in GBCAs can interfere with heavy metals, platinum and selenium analysis of biological fluids using ICP-MS. Within one year, our institution’s metals laboratory had to cancel 42 selenium serum tests and 19 heavy metal urine panels due to potential interference caused by gadolinium. Conclusions GBCAs will continue to be utilized in hospitals around the world. However, clinical laboratories should be wary of potential interferences caused by GBCAs. Relevant interferences include space charge effect, double charge interference, and the formation of polyatomic interferences caused by gadolinium. These interferences can negatively affect patient care by resulting in cancelled laboratory tests and causing patients to have blood redrawn and analysed at a later date leading to delays in their diagnosis/treatment.

Background: Arthroplasty implants commonly contain elemental metal that may undergo wear-related release. Recently, cases of hip implant-associated myocardial injury have been reported. However, we are not aware of any previous study that has systematically measured myocardial metal levels or examined the relationship with total hip arthroplasty (THA). Methods: Archives of our institution were queried for autopsies of individuals who had undergone THA between 1990 and 2013. Myocardial tissue samples were analyzed for cobalt (Co) and chromium (Cr) levels with inductively coupled plasma mass spectroscopy. Seventy-five Co/Cr-on-polyethylene THA cases were included (mean age at time of death = 77.4 years; 49% women) as were 73 non-arthroplasty controls matched for age, sex, and history of hypertension and diabetes mellitus. Results: Significantly higher median myocardial concentrations of Co were observed in individuals with THA compared with controls (0.12 versus 0.06 μg/g, p < 0.0001). The median Co concentration was 69% higher in patients who had undergone THA revision (0.169 μg/g) than in those who underwent primary THA (0.100 μg/g; p = 0.004). In general, higher Co levels were observed in those with multiple replaced joints, although this finding only trended toward significance. Cardiomegaly, interstitial fibrosis, and decreased ejection fraction were observed more frequently in the postmortem samples of patients with implants than in those of controls (p = 0.0002, 0.044, and 0.0039, respectively). Conclusions: We believe this to be the first study to quantify metal levels in cardiac tissue in patients with and without joint replacement. The elevated Co levels, in concert with cardiomegaly and increased interstitial fibrosis found during autopsy, in the arthroplasty cohort are novel, important findings. Although Co levels were significantly elevated above those in controls, the majority were below those seen in clinical case reports of death from Co cardiotoxicity associated with metal-on-metal prostheses. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.