Prognostic value of dehydroepiandrosterone-sulfate and other parameters of adrenal function in acute ischemic stroke

BACKGROUND AND PURPOSE: Acute stroke has a high morbidity and mortality. We evaluated the predictive value of adrenal function testing in acute ischemic stroke. METHODS: In a cohort of 231 acute ischemic stroke patients, we measured dehydroepiandrosterone (DHEA), DHEA-Sulfate (DHEAS), cortisol at baseline and 30 minutes after stimulation with 1 ug ACTH. Delta cortisol, the amount of rise in the 1 ug ACTH-test, was calculated. Primary endpoint was poor functional outcome defined as modified Rankin scale 3-6 after 1 year. Secondary endpoint was nonsurvival after 1 year. RESULTS: Logistic regression analysis showed that DHEAS (OR 1.21, 95% CI 1.01-1.49), but not DHEA (OR 1.01, 95% CI 0.99-1.04), was predictive for adverse functional outcome. Neither DHEA (OR 0.99, 95% CI 0.96-1.03) nor DHEAS (OR 1.10, 95% CI 0.82-1.44) were associated with mortality. Baseline and stimulated cortisol were predictive for mortality (OR 1.41, 95% CI 1.20-1.71; 1.35, 95% CI 1.15-1.60), but only basal cortisol for functional outcome (OR 1.20, 95% CI 1.04-1.38). Delta cortisol was not predictive for functional outcome (OR 0.86, 95% CI 0.71-1.05) or mortality (OR 0.92, 95% CI 0.72-1.17). The ratios cortisol/DHEA and cortisol/DHEAS discriminated between favorable outcome and nonsurvival (both p<0.0001) and between unfavorable outcome and nonsurvival (p = 0.0071 and 0.0029), but are not independent predictors for functional outcome or mortality in multivariate analysis (adjusted OR for functional outcome for both 1.0 (95% CI 0.99-1.0), adjusted OR for mortality for both 1.0 (95% CI 0.99-1.0 and 1.0-1.01, respectively)). CONCLUSION: DHEAS and the cortisol/DHEAS ratio predicts functional outcome 1 year after stroke whereas cortisol levels predict functional outcome and mortality. TRIAL REGISTRATION: ClinicalTrials.gov NCT00390962 (Retrospective analysis of this cohort)

Heat and mass transfer models and measurements for low-temperature storage of biological systems

Living systems are routinely exposed to low temperatures, and their corresponding response has been of scientific and medical interest for centuries. The basic physicochemical phenomena that govern the response of the living systems to subzero temperatures are complex and interactively coupled so that the prediction and regulation of the associated events are often difficult. However, during the past several decades, significant progress has been made in devising useful techniques to further our understanding of biological systems at ultralow temperatures. This chapter presents some of the heat and mass transfer models and associated measurements in biological systems exposed to low temperatures specifically as applied to cryopreservation protocols