Serum and tissue metallome of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) patients have late presentation at the time of diagnosis and a poor prognosis. Metal dyshomeostasis is known to play a role in cancer progression. However, the blood and tissue metallome of PDAC patients has not been assessed. This study aimed to determine the levels of essential and toxic metals in the serum and pancreatic tissue from PDAC patients. Serum samples were obtained from PDAC patients before surgical resection. Tissue (tumor and adjacent normal pancreas) were obtained from the surgically resected specimen. Inductively coupled plasma-mass spectrometry (ICP-MS) analysis was performed to quantify the levels of 10 essential and 3 toxic metals in these samples. Statistical analysis was performed to identify dysregulated metals in PDAC and their role as potential diagnostic and prognostic biomarkers. Significantly decreased serum levels of magnesium, potassium, calcium, iron, zinc, selenium, arsenic, and mercury and increased levels of molybdenum were shown to be associated with PDAC. There were significantly decreased levels of zinc, manganese and molybdenum, and increased levels of calcium and selenium in the pancreatic tumor tissue compared with the adjacent normal pancreas. Notably, lower serum levels of calcium, iron, and selenium, and higher levels of manganese, were significantly associated with a poor prognosis (i.e., overall survival) in PDAC patients. In conclusion, this is the first study to comprehensively assess the serum and tissue metallome of PDAC patients. It identified the association of metals with PDAC diagnosis and prognosis.

Analytical performance specifications for trace elements in biological fluids derived from six countries federated external quality assessment schemes over 10 years.

OBJECTIVES: This article defines analytical performance specifications (APS) for evaluating laboratory proficiency through an external quality assessment scheme. METHODS: Standard deviations for proficiency assessment were derived from Thompson's characteristic function applied to robust data calculated from participants' submissions in the Occupational and Environmental Laboratory Medicine (OELM) external quality assurance scheme for trace elements in serum, whole blood and urine. Characteristic function was based on two parameters: (1) ß - the average coefficient of variation (CV) at high sample concentrations; (2) α - the average standard deviation (SD) at low sample concentrations. APSs were defined as 1.65 standard deviations calculated by Thompson's approach. Comparison between OELM robust data and characteristic function were used to validate the model. RESULTS: Application of the characteristic function allowed calculated APS for 18 elements across three matrices. Some limitations were noted, particularly for elements (1) with no sample concentrations near analytical technique limit of detection; (2) exhibiting high robust CV at high concentration; (3) exhibiting high analytical variability such as whole blood Tl and urine Pb; (4) with an unbalanced number of robust SD above and under the characteristic function such as whole blood Mn and serum Al and Zn. CONCLUSIONS: The characteristic function was a useful means of deriving APS for trace elements in biological fluids where biological variation data or outcome studies were not available. However, OELM external quality assurance scheme data suggests that the characteristic functions are not appropriate for all elements.

Life-threatening barium carbonate poisoning managed with intravenous potassium, continuous veno-venous haemodialysis and endoscopic removal of retained ceramic glazes.

INTRODUCTION: Barium poisoning is rare but potentially severe. We describe a case of acute barium carbonate poisoning with cardiac arrest, managed with intravenous potassium, dialysis and endoscopic removal of retained ceramic glazes. CASE REPORT: A 38-year-old woman presented with vomiting 90 min after ingesting 3 cups of barium and strontium carbonate. Initial bloods noted potassium 2.8 mmol/L and creatinine 53 µmol/L. Electrocardiogram demonstrated prolonged corrected QT interval 585msec. Initial management included intravenous potassium. Four hours post-ingestion she developed proximal muscle weakness in upper limbs with a potassium of 2.2 mmol/L. At 15 h post-ingestion she developed profound muscle weakness, polymorphic ventricular tachycardia and cardiac arrest. Treatment included defibrillation, endotracheal intubation and continuous veno-venous haemodialysis (CVVHD) for metabolic derangement and enhanced elimination of barium. Chest X-ray 17 h post-ingestion demonstrated a large radio-opaque mass in the stomach, thought to be the ceramic glaze. Endoscopy removed the retained material 41 h post-ingestion. She was extubated 58 h post-ingestion and CVVHD was ceased on day 3. Serum creatinine peaked at 348 µmol/L on day 7, but normalised by discharge. Biphasic barium concentrations were noted, notably 94 µmol/L on admission, 195 µmol/L at 16 h, 95 µmol/L at 20 h, and 193 µmol/L at 30 h post-ingestion. CONCLUSION: In barium poisoning with hypokalaemia, prompt potassium supplementation is required but rebound hyperkalaemia can occur. Endoscopic removal of ceramic glazes may be useful more than 12 h post-ingestion. Consider extracorporeal methods to enhance barium elimination in severe cases.

Determination of vitamin B12 in equine urine by liquid chromatography - inductively coupled plasma - mass spectrometry.

Regulating authorities in the racing industry have restricted the administration of potentially performance enhancing cobalt salts to horses. There are severe penalties for trainers presenting horses with elevated urine cobalt concentrations, and compliance is ensured via analysis of total urinary cobalt at thresholds of 100 µg/L. When cobalt is present as part of the cobalamin molecule it is not considered performance enhancing. This paper demonstrates that a horse can excrete a significant proportion of a commercially available vitamin B12 injection in urine without metabolic modification. A liquid chromatography - inductively coupled plasma - mass spectrometry (LC-ICP-MS) method is presented for urinary cobalt speciation. Given the serious nature surrounding performance enhancing drug offences, we conclude that presumptive positives identified by urine total cobalt measurements require further analysis to differentiate inorganic cobalt from vitamin B12.

Microfluidic high performance liquid chromatography-chip hyphenation to inductively coupled plasma-mass spectrometry.

The Agilent Chip Cube Interface is a microfluidic chip-based technology originally designed for nanospray molecular mass spectrometry in which the sample enrichment, nano-column, tubing, connectors and spray tip were integrated into a single biocompatible chip. Here we describe the hyphenation of the Chip Cube Interface to ICP-MS via modification of the standard HPLC chip design and a new total consumption nebuliser suitable for flow rates as low as 300nLmin-1. The potential of the instrument to eliminate common nanoLC - ICP-MS shortcomings such as leaks, blockages and band-broadening was demonstrated via analysis of cyanocobalamin in equine plasma. The method was linear over three orders of magnitude with an r2 of 0.9999, the peak area repeatability was 1.9% (n=7), and the detection limit was 14ngmL-1. This novel configuration of the Chip Cube Interface coupled to ICP-MS is a suitable platform for the analysis of biomolecules associated with trace metals and speciation applications.