Alzheimer's Disease: Significant Benefit from the Yeast-Based Models.

Alzheimer's disease (AD) is an age-related, multifaceted neurological disorder associated with accumulation of aggregated proteins (amyloid Aß and hyperphosphorylated tau), loss of synapses and neurons, and alterations in microglia. AD was recognized by the World Health Organization as a global public health priority. The pursuit of a better understanding of AD forced researchers to pay attention to well-defined single-celled yeasts. Yeasts, despite obvious limitations in application to neuroscience, show high preservation of basic biological processes with all eukaryotic organisms and offer great advantages over other disease models due to the simplicity, high growth rates on low-cost substrates, relatively simple genetic manipulations, the large knowledge base and data collections, and availability of an unprecedented amount of genomic and proteomic toolboxes and high-throughput screening techniques, inaccessible to higher organisms. Research reviewed above clearly indicates that yeast models, together with other, more simple eukaryotic models including animal models, C. elegans and Drosophila, significantly contributed to understanding Aß and tau biology. These models allowed high throughput screening of factors and drugs that interfere with Aß oligomerization, aggregation and toxicity, and tau hyperphosphorylation. In the future, yeast models will remain relevant, with a focus on creating novel high throughput systems to facilitate the identification of the earliest AD biomarkers among different cellular networks in order to achieve the main goal-to develop new promising therapeutic strategies to treat or prevent the disease.

A randomized, double-blind trial comparing the effect of two blood pressure targets on global brain metabolism after out-of-hospital cardiac arrest.

PURPOSE: This study aimed to assess the effect of different blood pressure levels on global cerebral metabolism in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA). METHODS: In a double-blinded trial, we randomly assigned 60 comatose patients following OHCA to low (63 mmHg) or high (77 mmHg) mean arterial blood pressure (MAP). The trial was a sub-study in the Blood Pressure and Oxygenation Targets after Out-of-Hospital Cardiac Arrest-trial (BOX). Global cerebral metabolism utilizing jugular bulb microdialysis (JBM) and cerebral oxygenation (rSO2) was monitored continuously for 96 h. The lactate-to-pyruvate (LP) ratio is a marker of cellular redox status and increases during deficient oxygen delivery (ischemia, hypoxia) and mitochondrial dysfunction. The primary outcome was to compare time-averaged means of cerebral energy metabolites between MAP groups during post-resuscitation care. Secondary outcomes included metabolic patterns of cerebral ischemia, rSO2, plasma neuron-specific enolase level at 48 h and neurological outcome at hospital discharge (cerebral performance category). RESULTS: We found a clear separation in MAP between the groups (15 mmHg, p < 0.001). Cerebral biochemical variables were not significantly different between MAP groups (LPR low MAP 19 (16-31) vs. high MAP 23 (16-33), p = 0.64). However, the LP ratio remained high (> 16) in both groups during the first 30 h. During the first 24 h, cerebral lactate > 2.5 mM, pyruvate levels > 110 µM, LP ratio > 30, and glycerol > 260 µM were highly predictive for poor neurological outcome and death with AUC 0.80. The median (IQR) rSO2 during the first 48 h was 69.5% (62.0-75.0%) in the low MAP group and 69.0% (61.3-75.5%) in the high MAP group, p = 0.16. CONCLUSIONS: Among comatose patients resuscitated from OHCA, targeting a higher MAP 180 min after ROSC did not significantly improve cerebral energy metabolism within 96 h of post-resuscitation care. Patients with a poor clinical outcome exhibited significantly worse biochemical patterns, probably illustrating that insufficient tissue oxygenation and recirculation during the initial hours after ROSC were essential factors determining neurological outcome.

Blood-Pressure Targets in Comatose Survivors of Cardiac Arrest.

BACKGROUND: Evidence to support the choice of blood-pressure targets for the treatment of comatose survivors of out-of-hospital cardiac arrest who are receiving intensive care is limited. METHODS: In a double-blind, randomized trial with a 2-by-2 factorial design, we evaluated a mean arterial blood-pressure target of 63 mm Hg as compared with 77 mm Hg in comatose adults who had been resuscitated after an out-of-hospital cardiac arrest of presumed cardiac cause; patients were also assigned to one of two oxygen targets (reported separately). The primary outcome was a composite of death from any cause or hospital discharge with a Cerebral Performance Category (CPC) of 3 or 4 within 90 days (range, 0 to 5, with higher categories indicating more severe disability; a category of 3 or 4 indicates severe disability or coma). Secondary outcomes included neuron-specific enolase levels at 48 hours, death from any cause, scores on the Montreal Cognitive Assessment (range, 0 to 30, with higher scores indicating better cognitive ability) and the modified Rankin scale (range, 0 to 6, with higher scores indicating greater disability) at 3 months, and the CPC at 3 months. RESULTS: A total of 789 patients were included in the analysis (393 in the high-target group and 396 in the low-target group). A primary-outcome event occurred in 133 patients (34%) in the high-target group and in 127 patients (32%) in the low-target group (hazard ratio, 1.08; 95% confidence interval [CI], 0.84 to 1.37; P = 0.56). At 90 days, 122 patients (31%) in the high-target group and 114 patients (29%) in the low-target group had died (hazard ratio, 1.13; 95% CI, 0.88 to 1.46). The median CPC was 1 (interquartile range, 1 to 5) in both the high-target group and the low-target group; the corresponding median modified Rankin scale scores were 1 (interquartile range, 0 to 6) and 1 (interquartile range, 0 to 6), and the corresponding median Montreal Cognitive Assessment scores were 27 (interquartile range, 24 to 29) and 26 (interquartile range, 24 to 29). The median neuron-specific enolase level at 48 hours was also similar in the two groups. The percentages of patients with adverse events did not differ significantly between the groups. CONCLUSIONS: Targeting a mean arterial blood pressure of 77 mm Hg or 63 mm Hg in patients who had been resuscitated from cardiac arrest did not result in significantly different percentages of patients dying or having severe disability or coma. (Funded by the Novo Nordisk Foundation; BOX ClinicalTrials.gov number, NCT03141099.).

Oxygen Targets in Comatose Survivors of Cardiac Arrest.

BACKGROUND: The appropriate oxygenation target for mechanical ventilation in comatose survivors of out-of-hospital cardiac arrest is unknown. METHODS: In this randomized trial with a 2-by-2 factorial design, we randomly assigned comatose adults with out-of-hospital cardiac arrest in a 1:1 ratio to either a restrictive oxygen target of a partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa (68 to 75 mm Hg) or a liberal oxygen target of a Pao2 of 13 to 14 kPa (98 to 105 mm Hg); patients were also assigned to one of two blood-pressure targets (reported separately). The primary outcome was a composite of death from any cause or hospital discharge with severe disability or coma (Cerebral Performance Category [CPC] of 3 or 4; categories range from 1 to 5, with higher values indicating more severe disability), whichever occurred first within 90 days after randomization. Secondary outcomes were neuron-specific enolase levels at 48 hours, death from any cause, the score on the Montreal Cognitive Assessment (ranging from 0 to 30, with higher scores indicating better cognitive ability), the score on the modified Rankin scale (ranging from 0 to 6, with higher scores indicating greater disability), and the CPC at 90 days. RESULTS: A total of 789 patients underwent randomization. A primary-outcome event occurred in 126 of 394 patients (32.0%) in the restrictive-target group and in 134 of 395 patients (33.9%) in the liberal-target group (hazard ratio, 0.95; 95% confidence interval, 0.75 to 1.21; P = 0.69). At 90 days, death had occurred in 113 patients (28.7%) in the restrictive-target group and in 123 (31.1%) in the liberal-target group. On the CPC, the median category was 1 in the two groups; on the modified Rankin scale, the median score was 2 in the restrictive-target group and 1 in the liberal-target group; and on the Montreal Cognitive Assessment, the median score was 27 in the two groups. At 48 hours, the median neuron-specific enolase level was 17 µg per liter in the restrictive-target group and 18 µg per liter in the liberal-target group. The incidence of adverse events was similar in the two groups. CONCLUSIONS: Targeting of a restrictive or liberal oxygenation strategy in comatose patients after resuscitation for cardiac arrest resulted in a similar incidence of death or severe disability or coma. (Funded by the Novo Nordisk Foundation; BOX ClinicalTrials.gov number, NCT03141099.).

Bedside microdialysis for detection of early brain injury after out-of-hospital cardiac arrest.

Bedside detection and early treatment of lasting cerebral ischemia may improve outcome after out-of-hospital cardiac arrest (OHCA). This feasibility study explores the possibilities to use microdialysis (MD) for continuous monitoring of cerebral energy metabolism by analyzing the draining cerebral venous blood. Eighteen comatose patients were continuously monitored with jugular bulb and radial artery (reference) MD following resuscitation. Median time from cardiac arrest to MD was 300 min (IQR 230-390) with median monitoring time 60 h (IQR 40-81). The lactate/pyruvate ratio in cerebral venous blood was increased during the first 20 h after OHCA, and significant differences in time-averaged mean MD metabolites between jugular venous and artery measurements, were documented (p < 0.02). In patients with unfavorable outcome (72%), cerebral venous lactate and pyruvate levels remained elevated during the study period. In conclusion, the study indicates that jugular bulb microdialysis (JBM) is feasible and safe. Biochemical signs of lasting ischemia and mitochondrial dysfunction are frequent and associated with unfavorable outcome. The technique may be used in comatose OHCA patients to monitor biochemical variables reflecting ongoing brain damage and support individualized treatment early after resuscitation.

Yarrowia lipolytica: a multitalented yeast species of ecological significance.

Yarrowia lipolytica is characterized by GRAS (Generally regarded as safe) status, the versatile substrate utilization profile, rapid utilization rates, metabolic diversity and flexibility, the unique abilities to tolerate to extreme environments (acidic, alkaline, hypersaline, heavy metal-pollutions and others) and elevated biosynthesis and secreting capacities. These advantages of Y. lipolytica allow us to consider it as having great ecological significance. Unfortunately, there is still a paucity of relevant review data. This mini-review highlights ecological ubiquity of Y. lipolytica species, their ability to diversify and colonize specialized niches. Different Y. lipolytica strains, native and engineered, are beneficial in degrading many environmental pollutants causing serious ecological problems worldwide. In agriculture has a potential to be a bio-control agent by stimulating plant defense response, and an eco-friendly bio-fertilizer. Engineered strains of Y. lipolytica have become a very promising platform for eco-friendly production of biofuel, commodities, chemicals and secondary metabolites of plant origin, obtaining which by other method were limited or economically infeasible, or were accompanied by stringent environmental problems. Perspectives to use potential of Y. lipolytica's capacities for industrial scale production of valuable compounds in an eco-friendly manner are proposed.

Rotary-based platform with disposable fluidic modules for automated isolation of nucleic acids.

We describe the development and evaluation of a rotary-based platform with multiple disposable fluidic modules for simultaneous automatic nucleic acid (NA) isolation from up to 24 biological samples. The procedure is performed inside insulated individual disposable modules, which minimizes both the risk of infection of personnel and laboratory cross-contamination. Each module is a segment of a circular cylinder containing a leak-proof inlet port for sample input, reservoirs with lyophilized chemicals and solvents, fluidic channels, stoppers, valves, a waste reservoir and an outlet port equipped with the standard micro test tube for NA collection. The entire platform, apart from the rotor that accommodates 24 modules, consists of functional elements that provide spinning of the rotor, reagent mixing, pressure delivery, and heating of reaction mixtures. The transfer of the reaction mixtures inside the modules is performed either with rotation of the rotor or with excessive air pressure applied to the module's reservoirs. The entire process takes less than 40 min, starting from the sample loading to the recovery of the purified NA, and it allows NA isolation both from bacterial cells and viral particles. The feasibility and reproducibility of the developed platform was demonstrated by the NA isolation from suspensions of Bacillus thuringiensis and Mycobacterium tuberculosis cells within a concentration range of 10(8) to 10(2) cells/ml. Isolation of NAs from blood plasma samples with varying concentration of hepatitis B and C viruses from 10(7) to 10(2) particles/ml were also successful. The purity and integrity of the extracted NAs were both reliable for performing quantitative PCR.

Evaluation of molecularity of rate-limiting step of pore formation by antimicrobial peptides studied using mitochondria as a biosensor.

Toxic agents, derived from bee or hornet venoms and from fungi - melittin, mastoparan, and alamethicin are able to permeabilize biological membranes. We studied the initial steps of pore formation by these peptides in rat liver mitochondria preparations (RLM) generating transmembrane potential (ΔΨ). RLM has been used as a potassium transmembrane current (PTC) sensor. The PTC induced in RLM depends linearly on the degree of steady-state activation of RLM respiration. The concentration order of such activation by melittin in a "potassium" incubation medium containing 6mM Mg(2+) was 2.01±0.15. In the case of mastoparan, the reaction order was 1.83±0.23. The first steady-state phase of activation of RLM respiration by alamethicin was not detected in "Tris" incubation medium; it appeared only after addition of KCl. The order of the reaction limiting such activation was 1.92±0.07. It is suggested that PTC in this phase is determined by the channels with the lowest degree of oligomerization formed by "dimers". The ratio of equally active membrane concentrations of peptides obviously reflects the ratio of average lifetimes (ALT) for corresponding "dimers" (alamethicin and melittin, 38.5; mastoparan and melittin, 0.32). It is concluded that the results of this investigation may be useful for comparative testing of perspective pharmaceuticals.