Suchergebnisse

Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies.This reviewwill discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed. ; Work in the authors' laboratory is partly funded by the Malta Government Scholarship Scheme (MGSS) award, fund number ME 367/07/8, to Gianluca Farrugia and partly by Research Fund grants to Rena Balzan from the University of Malta. ; peer-reviewed

Toxic substances generated during the metabolism of alcohol in the liver may contribute to the development of alcoholic liver disease. These substances include highly reactive molecules that can destroy vital cell components through a process called oxidation. Cells are protected against oxidation by the action of certain enzymes, vitamins, and other substances, known collectively as antioxidants. An imbalance between oxidants and antioxidants can lead to oxidative stress, characterized by escalating cell damage. Evidence suggests that the major energy-generating structures within cells (i.e., mitochondria) may be especially sensitive to oxidative stress, resulting in diminished energy production. Medications that reduce oxidative stress in mitochondria may ameliorate liver disease. ; The work presented in this review was supported by National Institute of Alcohol Abuse and Alcoholism grant AA09526, Direccion General Politica Cientifica y Tecnica grant PM 95–0185, Fondo Investigaciones Sanitarias grant FISS 94–0046/01, Plan Nacional de I+D grant SAF 97–0087–C01, and Europharm ; Peer Reviewed

Increased excitotoxity in response to stressors leads to oxidative stress (OS) due to accumulation of excess reactive oxygen/nitrogen species. Neuronal membrane phospholipids are especially susceptible to oxidative damage, which alters signal transduction mechanisms. The Contingent of International Operations (CIO) has been subjected to various extreme stressors that could cause Posttraumatic Stress Disorder (PTSD). Former studies suggest that heterogeneity due to gender, race, age, nutritional condition and variable deployment factors and stressors produce challenges in studying these processes. The research aim was to assess OS levels in the PTSD risk group in CIO. In a prospective study, 143 participants who were Latvian CIO, regular personnel, males, Europeans, average age of 27.4, with the same tasks during the mission, were examined two months before and immediately after a six-month Peace Support Mission (PSM) in Afghanistan. PCL-M questionnaire, valid Latvian language "Military" version was used for PTSD evaluation. Glutathione peroxidase (GPx), superoxide dismutase (SOD) and lipid peroxidation intensity and malondialdehyde (MDA) as OS indicators in blood were determined. Data were processed using SPSS 20.0. The MDA baseline was 2.5582 μM, which after PSM increased by 24.36% (3.1815 μM). The GPx baseline was 8061.98 U/L, which after PSM decreased by 9.35% (7308.31 U/L). The SOD baseline was 1449.20 U/gHB, which after PSM increased by 2.89% (1491.03 U/gHB). The PTSD symptom severity (total PCL-M score) baseline was 22.90 points, which after PSM increased by 14.45% (26.21 points). The PTSD Prevalence rate (PR) baseline was 0.0357, which after PSM increased by 147.06% (0.0882). We conclude that there is positive correlation between increase of OS, PTSD symptoms severity level, and PTSD PR in a group of patients with risk of PTSD - CIO. PTSD PR depends on MDA intensity and OS severity. OS and increased free radical level beyond excitotoxity, is a possible causal factor for clinical manifestation of PTSD

Contribution of oxidative stress to neurodegenerative disease
Paul A. Hyslop, from Arkley BioTek Indianapolis, details an ongoing specific research approach to identify, characterize, and validate physiologically relevant neuronal targets of H2O2 in designing therapeutics for neurodegenerative disease progression. The societal impact of dementia resulting from the major neurodegenerative diseases such as Alzheimer's presents a growing and significant unmet medical need. (1) Various cellular metabolic and structural deficits, neuroinflammation, and oxidative stress are known to result in the progressive loss of vulnerable non-regenerative neurons. (2)

AbstractAnimal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still‐face (SF) and still‐face with maternal touch (SF+T). Maternal and infant cortisol levels were sampled at baseline, reactivity, and recovery and mother's and infant's cardiac vagal tone were measured during the free play, still‐face, and reunion episodes of the procedure. Cortisol reactivity was higher among infants in the SF condition and while cortisol decreased at recovery for infants in the SF+T, it further increased for those in the SF. Vagal tone showed a greater suppression when SF was not accompanied by maternal touch. Touch synchrony during free play was associated with higher infant vagal tone, whereas touch myssynchrony – maternal tactile stimulation while the infant gaze averts – correlated with higher maternal and infant cortisol. In humans, as in mammals, the provision of touch during moments of maternal unavailability reduces infants' physiological reactivity to stress.

Abstract
Background One of the antioxidant mechanisms is the dynamic balance between thiol and disulfide, which, in subarachnoid hemorrhage and other chronic diseases, is disrupted in favor of the latter. The two most commonly used oxidative stress (OS) biochemical markers are the oxidative stress index (OSI) value, which indicates the total oxidant status (TOS) and total antioxidant status (TAS) balance, and the thiol–disulfide (TDS) value, which indicates the total thiol (TT) and native thiol (NT) balance. High OS levels require further investigations. We aimed to investigate the OS level in aneurysmal SAH (aSAH) patients.
methods In this clinical prospective study, blood samples were collected from 50 consecutively treated patients with aSAH and 50 volunteers. Serum TOS, TAS, TT, and NT levels were measured using Erel's method via a spectrophotometer. The Glasgow Coma Scale (GCS) scores, Fisher grades, length of hospital stay (LOS), and the Glasgow Outcome Scale (GOS) scores were recorded. Consequently, the OSI and TDS values were calculated in all participants.
Results A statistically significant difference was observed in the TAS, TOS, OSI, and TDS values between the aSAH patients and the controls. The TT and NT values were significantly lower in aSAH patients than in the controls. A correlation was identified between the OSI values and the GCS scores. Although a correlation was observed between the TDS values and the LOS, no correlation was found between the OSI and the TDS values.
Conclusion The OSI and TDS, which are OS indicators, might serve as the additional objective nominal data to evaluate the treatment efficacy and follow-up for SAH patients. Moreover, decreasing the OSI values and increasing the TT values can be used as improvement indicators in the treated aSAH patients. If we can reduce the OS at the early stage of SAH, it could improve the prognosis by reducing both the morbidity and mortality rates. Further randomized investigations are required to prove the findings in this prospective study.

Military personnel are particularly exposed to stressful events, and overexposure to stress is both physically and mentally unhealthy. While stress management programs, such as the Tactics of Optimized Potential (TOP) and Heart Coherence (HC) have been implemented, their efficiency remains to be evaluated. The objective of this randomized control trial was to evaluate the effectiveness of the two programs among a young male population of 180 military fire fighter recruits. Based on two psychological, and one physiological measurement, namely heart rate variability (HRV), we found that both TOP and HC programs significantly increased HRV. This is promising as we know that higher HRV is consistent with better health, in most cases. Moreover, the TOP program significantly reduced perceived stress and negative mood, unlike the HC program. Combining these results, we conclude that while both TOP and HC programs influence physiological measurements, only the TOP modifies psychological evaluations. Finally, we distinguished the effects of the programs on two samples characterized by their HRV level. For the low HRV group, both programs tended to increase their HRV level, while for the high HRV group neither program had a significant effect.