Analysis of striatum and brain levels reveals sex differences in conversion of methamphetamine to amphetamine in mice.

The aim of this study was to compare methamphetamine (Meth) and amphetamine (Amph) levels in the brain of male and female mice. Meth and Amph levels were significantly higher at 30 min after systemic administration of 2 mg/kg of Meth than at 120 min. Meth levels were similar in striatum as in the rest of the brain and there was no sex difference. However, females showed significantly higher levels of Amph compared to males in both regions. The ratio of Amph to Meth levels was significantly higher in female mice than in males at 120 min after Meth administration. In a separate cohort of mice, treatment with 3 mg/kg of Meth induced significant locomotor hyperactivity which was maximum in the first 60 min after injection and not different between male and female mice. Treatment with 1 mg/kg Meth induced mild hyperactivation in female, but not male mice at 60-120 min post-injection. These data show sex differences in conversion of Meth to Amph in mice, which could play a role in sex differences in the behavioural, addictive and neurotoxic properties of Meth in rodents as well as in humans.

Misclassification of calcium status in end-stage kidney disease using albumin-adjusted calcium levels.

BACKGROUND: Albumin-adjusted calcium remains widely used in clinical practice with guidelines for chronic kidney disease (CKD) mineral bone disorder recommending the use of serum calcium for monitoring. This is despite ionized calcium being the biologically active fraction. This study aimed to investigate the ability of total calcium and albumin-adjusted calcium to correctly assign calcium status in stage 5/5D CKD across non-dialysis, haemodialysis and peritoneal dialysis patients. METHODS: Over a 6-months, 352 paired serum and ionized calcium samples were collected from stage 5 (n = 58) and 5D (n = 294, 196 haemodialysis, 98 peritoneal dialysis) CKD patients in a tertiary-hospital setting. Albumin-adjusted calcium was calculated using the modified-Payne formula. Ionized calcium was the reference standard. The agreement between the two methods in assigning calcium status was assessed using Cohen's weighted kappa (κ) statistic. RESULTS: Albumin-adjusted calcium was a poor predictor of calcium status compared to ionized calcium in stage 5/5D CKD (observed agreement 0.42, weighted κ 0.20, 95% CI 0.15-0.26). Dialysis dependence was associated with worse agreement (observed agreement 0.38, weighted κ 0.14, 95% CI 0.09-0.19). Total calcium was more reliable, however, remained inaccurate. Calcium status was not more accurately classified in those with higher albumin levels ≥30 g/L (observed agreement 0.47, weighted κ 0.23, 95% CI 0.10-0.36). CONCLUSION: Total calcium provides better approximation of calcium status than albumin-adjusted calcium in stage 5/5D CKD. Albumin-adjusted calcium tends to 'overcorrect' serum calcium upward. Clinicians should use ionized calcium where accurate measure of calcium is indicated, with total calcium used as the next best option where resources are limited.

Troponin least significant change (z-score) is associated with poor clinical outcomes in patients presenting to the emergency department.

BACKGROUND: A rise and/or fall in high sensitivity cardiac troponin (hs-Tn) is critical in defining acute myocardial injury and therefore the diagnosis of acute myocardial infarction. A significant rise in hs-Tn is not well defined in current guidelines. Calculation of a z-score for two consecutive hs-Tn measurements is a method-independent measure of dynamic troponin elevation. However, the association of hs-Tn z-score with outcomes for unselected emergency department admissions is unknown. Moreover, the association of non-dynamic troponin elevations, as defined by a normal z-score, with clinical outcomes remains to be assessed. METHODS: We retrospectively calculated z-scores for patients presenting to emergency department over 18 months who had serial troponin measurements with at least one result >99th percentile using the Abbott hs-TnI assay. We assessed the association of z-score with discharge diagnosis, cardiac interventions, inpatient mortality, length of stay and readmission rates. RESULTS: There were 2062 presentations for 1830 patients where a z-score was calculated. Z-score was elevated in 1080 presentations. Dynamic troponin elevation (z-score ≥ 2) was associated with acute myocardial infarction (OR = 9.1, P < 0.01), admission to an inpatient unit (95 vs. 88%, P < 0.01), increased inpatient length of stay (97 vs. 65 days, P < 0.01), inpatient coronary intervention (21 vs. 6%, P < 0.01) and mortality (4.4 vs. 2.4%, P < 0.05) compared with myocardial injury with a static troponin elevation. CONCLUSIONS: Z-score is an assay-independent tool to alert clinicians of significant, dynamic troponin elevation and acute myocardial injury. It is associated with poorer clinical outcomes.

Chronic methamphetamine interacts with BDNF Val66Met to remodel psychosis pathways in the mesocorticolimbic proteome.

Methamphetamine (Meth) abuse has reached epidemic proportions in many countries and can induce psychotic episodes mimicking the clinical profile of schizophrenia. Brain-derived neurotrophic factor (BDNF) is implicated in both Meth effects and schizophrenia. We therefore studied the long-term effects of chronic Meth exposure in transgenic mice engineered to harbor the human BDNFVal66Met polymorphism expressed via endogenous mouse promoters. These mice were chronically treated with an escalating Meth regime during late adolescence. At least 4 weeks later, all hBDNFVal66Met Meth-treated mice exhibited sensitization confirming persistent behavioral effects of Meth. We used high-resolution quantitative mass spectrometry-based proteomics to biochemically map the long-term effects of Meth within the brain, resulting in the unbiased detection of 4808 proteins across the mesocorticolimbic circuitry. Meth differentially altered dopamine signaling markers (e.g., Dat, Comt, and Th) between hBDNFVal/Val and hBDNFMet/Met mice, implicating involvement of BDNF in Meth-induced reprogramming of the mesolimbic proteome. Targeted analysis of 336 schizophrenia-risk genes, as well as 82 growth factor cascade markers, similarly revealed that hBDNFVal66Met genotype gated the recruitment of these factors by Meth in a region-specific manner. Cumulatively, these data represent the first comprehensive analysis of the long-term effects of chronic Meth exposure within the mesocorticolimbic circuitry. In addition, these data reveal that long-term Meth-induced brain changes are strongly dependent upon BDNF genetic variation, illustrating how drug-induced psychosis may be modulated at the molecular level by a single genetic locus.

A direct comparison of patient-based real-time quality control techniques: The importance of the analyte distribution.

BACKGROUND: Patient-based real-time quality control (PBRTQC) techniques have been described in clinical chemistry for over 50 years. PBRTQC has a number of advantages over traditional quality control including commutability, cost and the opportunity for real-time monitoring. However, there are few systematic investigations assessing how different PBRTQC techniques perform head-to-head. METHODS: In this study, we compare moving averages with and without truncation and moving medians. For analytes with skewed distributions such as alanine aminotransferase and creatinine, we also investigate the effect of Box-Cox transformation of the data. We assess the ability of each technique to detect simulated analytical bias in real patient data for multiple analytes and to retrospectively detect a real analytical shift in a creatinine and urea assay. RESULTS: For analytes with symmetrical distributions, we show that error detection is similar for a moving average with and without four standard deviation truncation limits and for a moving median. In contrast to analytes with symmetrically distributed results, moving averages perform poorly for right skewed distributions such as alanine aminotransferase and creatinine and function only with a tight upper truncation limit. Box-Cox transformation of the data both improves the performance of moving averages and allows all data points to be used. This was also confirmed for retrospective detection of a real analytical shift in creatinine and urea. CONCLUSIONS: Our study highlights the importance of careful assessment of the distribution of patient results for each analyte in a PBRTQC program with the optimal approaches dependent on whether the patient result distribution is symmetrical or skewed.

H/D exchange under mild conditions in arenes and unactivated alkanes with C6D6 and D2O using rigid, electron-rich iridium PCP pincer complexes.

The synthesis and characterization of an iridium polyhydride complex (Ir-H4) supported by an electron-rich PCP framework is described. This complex readily loses molecular hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8 and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation, deuteration levels can range from near exhaustive to selective only for sterically accessible sites. Preparative level deuterations of select substrates were performed allowing for procurement of >95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by treatment of residues with H2 and is still active for further reactions.

Proposed Addendum to 2012 Recommendations for Standardised Reporting of Protein Electrophoresis in Australia and New Zealand.

It is apparent that there is a need for greater harmonisation of the reporting and quantification of paraproteins on protein electrophoresis with the introduction of the electronic health record and recent survey findings indicating ongoing areas of heterogeneity on serum protein electrophoresis. The proposed addendum aims to update the 2012 recommendations for standardised reporting of protein electrophoresis in Australia and New Zealand. The sections which need to be updated include those on the quantification of gamma- and non-gamma-migrating paraproteins; interpretive commenting in specimens with a paraprotein and/or small abnormal bands; the utility of serum free light chains compared with Bence Jones protein measurement; and a new table with interpretive commenting for serum free light chains. It is expected that such standardised reporting will reduce both variation between laboratories and the risk of misinterpretation of results.

Paraprotein Sample Exchange in Australia and New Zealand - 2018.

Quantification of co-migrating paraproteins in the beta-region presents an ongoing challenge for laboratories performing serum protein electrophoresis. The between-laboratory variation may impact patient care if the patient uses different pathology services during plasma cell dyscrasia monitoring. To identify the practical difficulties and determine the extent of agreement in the reporting of beta-migrating paraproteins in Australia and New Zealand (NZ), sample exchanges were conducted in five Australian states and in NZ in early 2018. This study has highlighted the variation in quantification and reporting of beta-migrating paraproteins which could potentially affect patient monitoring and management.

Misclassification of Calcium Status Based on Albumin-Adjusted Calcium: Studies in a Tertiary Hospital Setting.

BACKGROUND: Clinical laboratories measure total calcium and adjust for albumin concentrations to predict calcium status. We compared total and adjusted calcium (Adj-Ca) with ionized calcium (Ca2+) for correct assignment of calcium status. The effect of restriction of Adj-Ca reporting in patients with hypoalbuminemia was determined on the basis of frequency of misclassifications. METHODS: Extraction of laboratory results was performed for 24 months. Adj-Ca was calculated from a modified Payne formula. A further prospective data set for 6 months was collected after stopping reporting of Adj-Ca for patients with an albumin <3.0 g/dL. The agreement between Ca2+ and Adj-Ca or total Ca was assessed with Cohen's kappa statistic. RESULTS: In 5553 hospitalized patients, 13604 paired Ca2+ results were analyzed retrospectively. Prospective collection in 1113 paired samples was from 450 patients. Adj-Ca was a poor predictor of calcium status compared to the Ca2+ reference standard in both data sets (agreement 56.9% in the first, 65.6% in the second data set). Renal failure and low albumin concentrations were associated with worse agreement between Adj-Ca and Ca2+. Restriction of reporting of Adj-Ca to albumin concentrations >3.0g/dL improved correct classification of calcium status from 65.6% to 77.6% (P < 0.0001). Total Ca performed better than Adj-Ca for low albumin (<3.0g/dL) and performed similarly in samples with albumin >3.0g/dL. CONCLUSIONS: Adj-Ca is unreliable for the classification of calcium status in hospital patients when compared to Ca2+. Adj-Ca overestimates calcium for patients with renal impairment and albumin concentrations <3.0g/dL. Restriction of reporting Adj-Ca for albumin below 3.0 g/dL reduces the number of misclassified patients.

Cationic mono and dicarbonyl pincer complexes of rhodium and iridium to assess the donor properties of PCcarbeneP ligands.

The donor properties of five different PCcarbeneP ligands are assessed by evaluation of the CO stretching frequencies in iridium(i) and rhodium(i) carbonyl cations. The ligands feature dialkyl phosphine units (R = (i)Pr or (t)Bu) linked to the central benzylic carbon by either an ortho-phenylene bridge, or a 2,3-benzo[b]thiophene linker; in the former, substituent patterns on the phenyl linker are varied. The carbonyl complexes are synthesized from the (PCcarbeneP)M-Cl starting materials via abstraction of the chlorides in the presence of CO gas. In addition to the expected mono carbonyl cations, products with two carbonyl ligands are produced, and for the rhodium example, a novel product in which the second carbonyl ligand adds reversibly across the Rh[double bond, length as m-dash]C bond to give an η(2) ketene moiety was characterized. The IR data for the complexes shows the 2,3-benzo[b]thiophene linked system to be the poorest overall donor, while the phenyl bridged ligands incorporating electron donating dialkyl amino groups para to the anchoring carbene are very strongly donating pincer arrays.

Should routine laboratories stop doing screening serum protein electrophoresis and replace it with screening immune-fixation electrophoresis? No quick fixes: Counterpoint.

Monoclonal gammopathies are characterised by the production of a monoclonal immunoglobulin or free light chains by an abnormal plasma cell or B-cell clone and may indicate malignancy or a precursor (MGUS). There is currently no consensus on the initial test or combination of tests to be performed in suspected monoclonal gammopathies but serum protein electrophoresis and urine protein electrophoresis are commonly requested as initial investigations. If abnormal, immunofixation electrophoresis is then performed to confirm the presence of paraprotein and to determine its heavy and light chain type. Recently, some groups have developed simplified "screening" IFE methods for use in parallel to SPEP for the detection monoclonal gammopathies. We argue here that screening IFE may be of benefit in clinical laboratories using SPEP with poor resolution in the ß-region, assisting in the detection of mainly IgA paraprotein, but may be of less benefit in laboratories utilising higher resolution gels. Further it may increase the detection of trace bands of questionable clinical significance, representing transient phenomena in infectious and auto-immune conditions or very low risk MGUS. The increased detection of these bands using screening IFE would require further patient follow up, possibly causing unnecessary patient anxiety and additional follow up healthcare costs.

The concise synthesis of unsymmetric triarylacetonitriles via Pd-catalyzed sequential arylation: a new synthetic approach to tri- and tetraarylmethanes.

The selective synthesis of multiarylated acetonitriles via sequential palladium-catalyzed arylations of chloroacetonitrile is reported. The three aryl groups are installed via a Pd-catalyzed Suzuki-Miyaura cross coupling reaction followed by back-to-back C-H arylations to afford triarylacetonitriles in three steps with no over-arylation at any step. The triarylacetonitrile products can be converted into highly functionalized species including tetraarylmethanes. This new strategy provides rapid access to a variety of unsymmetrical tri- and tetraarylmethane derivatives from simple, readily available starting materials.