Development and validation of high performance liquid chromatography method for the measurements of biogenic amines

Many important biogenic amines (dopamine, noradrenaline and serotonin) are produced from amino acids by enzyme-catalysed processes and play a prominent role in neuronal functions and therefore, they serve as pharmacological target for the treatment of neurological disorders, such as Alzheimer’s disease or Parkinson’s disease. The aim of the current study was to optimize a high-performance liquid chromatography method that allows selective separation of eight biogenic amines and some of their metabolites (levodopa, 3,4-dihydroxyphenylacetic acid, noradrenaline, 5-hydroxyindoleacetic acid, homovanillic acid, dopamine, serotonin and 3-methoxythyramine) using 3 internal standards with electrochemical detection. During the development of our method, we optimized the amount of ion pairing component, pH and the amount of organic phase. Several selective methods were tested, but the most effective one was used for validation process for mouse and rat brain regions, including the striatum, cortex and hippocampus. During validation, the limit of detection, the limit of quantification, recovery, intraday and interday precisions were determined for the eight analytes. The ranges of recovery were between 87 and 120%, the intraday and interday precision were < 10% in all cases. The limit of detection and quantification ranged around 2 and 10 ng/ml, respectively. The developed and optimized method ensures the measurement of the aforementioned biogenic amines from mouse and rat brain regions

Web-based decision support system for patient-tailored selection of antiseizure medication in adolescents and adults: An external validation study

Antiseizure medications (ASMs) should be tailored to individual characteristics, including seizure type, age, sex, comorbidities, co-medications, drug allergies, and child-bearing potential. We previously developed a web-based algorithm for patient-tailored ASM selection to assist healthcare professionals in prescribing medication using a decision support application (https://epipick.org). In this validation study, we used an independent dataset to assess whether ASMs recommended by the algorithm are associated with better outcomes than ASMs considered less desirable by the algorithm. Four hundred and twenty-five consecutive patients with newly diagnosed epilepsy were followed for at least one year after starting an ASM chosen by their physician. Patient characteristics were fed into the algorithm, blinded to the physician´s ASM choices and outcome. The algorithm recommended ASMs, ranked in hierarchical groups, with Group-1 ASMs labelled as best option for that patient. We evaluated retention rates, seizure-freedom rates and adverse effects leading to treatment discontinuation. Survival analysis contrasted outcomes between patients who received favored drugs and those who received lower ranked drugs. Propensity score matching corrected for possible imbalances between the groups. ASMs classified by the algorithm as best options had higher retention-rate (79.4% vs. 67.2%; p=0.005), higher seizure freedom rate (76.0% vs. 61.6%; p=0.002), and lower rate of discontinuation due to adverse effects (12.0% vs. 29.2%; p<0.001) than ASMs ranked less desirable by the algorithm. Use of the freely available decision-support system is associated with improved outcomes. This drug-selection application can provide valuable assistance to healthcare professionals prescribing medication for individuals with epilepsy

Electric Source Imaging in Presurgical Evaluation of Epilepsy: An Inter-Analyser Agreement Study

Mattioli P, Cleeren E, Hadady L, et al. Electric Source Imaging in Presurgical Evaluation of Epilepsy: An Inter-Analyser Agreement Study. Diagnostics. 2022;12(10): 2303.Electric source imaging (ESI) estimates the cortical generator of the electroencephalography (EEG) signals recorded with scalp electrodes. ESI has gained increasing interest for the presurgical evaluation of patients with drug-resistant focal epilepsy. In spite of a standardised analysis pipeline, several aspects tailored to the individual patient involve subjective decisions of the expert performing the analysis, such as the selection of the analysed signals (interictal epileptiform discharges and seizures, identification of the onset epoch and time-point of the analysis). Our goal was to investigate the inter-analyser agreement of ESI in presurgical evaluations of epilepsy, using the same software and analysis pipeline. Six experts, of whom five had no previous experience in ESI, independently performed interictal and ictal ESI of 25 consecutive patients (17 temporal, 8 extratemporal) who underwent presurgical evaluation. The overall agreement among experts for the ESI methods was substantial (AC1 = 0.65; 95% CI: 0.59-0.71), and there was no significant difference between the methods. Our results suggest that using a standardised analysis pipeline, newly trained experts reach similar ESI solutions, calling for more standardisation in this emerging clinical application in neuroimaging

The detection of age-, gender-, and region-specific changes in mouse brain tocopherol levels via the application of different validated HPLC methods

The aging process clearly increases the demand for antioxidant protection, especially in the brain, involving that provided by α-tocopherol (αT). However, little is known about the age-related changes in brain αT levels and the influencing effect of gender on it, in human or murine samples as well. Accordingly, the aim of the current study was to detect age-, gender- and region-specific changes in αT concentrations in mouse brain tissue and to assess the influencing effect of plasma αT levels on it. Female and male C57BL/6 mice at the ages of 6, 16 and 66 weeks (n = 9 in each group) were applied. αT levels were determined with high performance liquid chromatography (HPLC) from the striatum, cortex, hippocampus, cerebellum, brainstem and from plasma samples. A detailed validation process was carried out for the applied HPLC method as well. The results demonstrated that brain αT levels significantly increased in the striatum, cortex, and hippocampus with aging in both genders, but in a more pronounced way in females with an increasing magnitude of this difference. In case of the cerebellum, a moderate elevation could be detected only in females, whereas in case of the brainstem there was no significant change in αT level. With regard to plasma samples, no clear trend could be identified. The current study is the first to present age-dependent gender-specific changes in αT level in certain brain regions of the C57Bl/6 mouse strain, and may provide meaningful information for future therapeutic studies targeting aging-related processes. © 2018, Springer Science+Business Media, LLC, part of Springer Nature