Developing a multivariable prediction model for functional outcome after reperfusion therapy for acute ischaemic stroke: study protocol for the Targeting Optimal Thrombolysis Outcomes (TOTO) multicentre cohort study.

INTRODUCTION:Intravenous thrombolysis (IVT) with recombinant tissue plasminogen activator (rt-PA) is the only approved pharmacological reperfusion therapy for acute ischaemic stroke. Despite population benefit, IVT is not equally effective in all patients, nor is it without significant risk. Uncertain treatment outcome prediction complicates patient treatment selection. This study will develop and validate predictive algorithms for IVT response, using clinical, radiological and blood-based biomarker measures. A secondary objective is to develop predictive algorithms for endovascular thrombectomy (EVT), which has been proven as an effective reperfusion therapy since study inception. METHODS AND ANALYSIS:The Targeting Optimal Thrombolysis Outcomes Study is a multicenter prospective cohort study of ischaemic stroke patients treated at participating Australian Stroke Centres with IVT and/or EVT. Patients undergo neuroimaging using multimodal CT or MRI at baseline with repeat neuroimaging 24 hours post-treatment. Baseline and follow-up blood samples are provided for research use. The primary outcome is good functional outcome at 90 days poststroke, defined as a modified Rankin Scale (mRS) Score of 0-2. Secondary outcomes are reperfusion, recanalisation, infarct core growth, change in stroke severity, poor functional outcome, excellent functional outcome and ordinal mRS at 90 days. Primary predictive models will be developed and validated in patients treated only with rt-PA. Models will be built using regression methods and include clinical variables, radiological measures from multimodal neuroimaging and blood-based biomarkers measured by mass spectrometry. Predictive accuracy will be quantified using c-statistics and R2. In secondary analyses, models will be developed in patients treated using EVT, with or without prior IVT, reflecting practice changes since original study design. ETHICS AND DISSEMINATION:Patients, or relatives when patients could not consent, provide written informed consent to participate. This study received approval from the Hunter New England Local Health District Human Research Ethics Committee (reference 14/10/15/4.02). Findings will be disseminated via peer-reviewed publications and conference presentations

Multivariate analyses for biomarkers hunting and validation through on-tissue bottom-up or in-source decay in MALDI-MSI: application to prostate cancer.

peer reviewe

Anatomical Distribution of Lipids in Human Brain Cortex by Imaging Mass Spectrometry

[ES] Las imágenes de masa molecular de los tejidos estarán sesgadas si las diferencias en las propiedades fisicoquímicas del microentorno afectan a la intensidad de los espectros. Para abordar esta cuestión, hemos realizado -mediante espectrometría de masas MALDI-TOF- imágenes en cortes y análisis lipidómicos en extractos de corteza frontal, ambos procedentes de las mismas muestras de tejido postmortem de cerebro humano. Se utilizó una calibración externa para lograr una precisión de masa de 10 ppm (1σ) en los espectros de los extractos, aunque la asignación final se basó en una comparación con especies previamente reportadas. Los espectros registrados directamente a partir de cortes de tejido (imágenes) muestran excelentes relaciones s/n, casi comparables a las obtenidas a partir de los extractos. Además, conservan la información sobre la distribución anatómica de las especies moleculares presentes en el tejido congelado autopsiado. La comparación posterior entre los espectros procedentes de extractos lipídicos desprovistos de proteínas y los registrados directamente a partir del tejido demuestra de forma inequívoca que las diferencias en la composición lipídica entre la sustancia gris y la blanca observadas en las imágenes de masa no son un artefacto debido a las influencias microambientales de cada zona anatómica sobre la intensidad de la señal, sino variaciones reales en la composición lipídica.[EN] Molecular mass images of tissues will be biased if differences in the physicochemical properties of the microenvironment affect the intensity of the spectra. To address this issue, we have performed—by means of MALDI-TOF mass spectrometry—imaging on slices and lipidomic analysis in extracts of frontal cortex, both from the same postmortem tissue samples of human brain. An external calibration was used to achieve a mass accuracy of 10 ppm (1σ) in the spectra of the extracts, although the final assignment was based on a comparison with previously reported species. The spectra recorded directly from tissue slices (imaging) show excellent s/n ratios, almost comparable to those obtained from the extracts. In addition, they retain the information about the anatomical distribution of the molecular species present in autopsied frozen tissue. Further comparison between the spectra from lipid extracts devoid of proteins and those recorded directly from the tissue unambiguously show that the differences in lipid composition between gray and white matter observed in the mass images are not an artifact due to microenvironmental influences of each anatomical area on the signal intensity, but real variations in the lipid composition.This study was supported by the Spanish Ministry ofEducation and Science (SAF2007-60211), the BasqueGovernment (IT-325-07, IT-336-10, IT-440-10 and SAI07/46), Biscay County Council (DIPE07/05), Carlos III HealthInstitute (FIS PI070628), and UPV/EHU GIU07/50. IM andAV are recipients of UPV/EHU graduate fellowships. GB issupported by a grant from the UPV/EHU ResearchersSpecialization Progra