n/a

The effects of short-term hyperoxia on age-related diseases and aging biomarkers have been reported in animal and human experiments using different protocols; however, the findings of the studies remain conflicting. In this systematic review, we summarized the existing reports in the effects of short-term hyperoxia on age-related diseases, hypoxiainducible factor 1α (HIF-1α), and other oxygen-sensitive transcription factors relevant to aging, telomere length, cellular senescence, and its side effects. This review was done as described in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. A systematic search was done in PubMed, Google Scholar, and Cochrane Library and from the references of selected articles to identify relevant studies until May 2021. Of the total 1,699 identified studies, 17 were included in this review. Most of the studies have shown significant effects of short-term hyperoxia on age-related diseases and aging biomarkers. The findings of the studies suggest the potential benefits of short-term hyperoxia in several clinical applications such as for patients undergoing stressful operations, restoration of cognitive function, and the treatment of severe traumatic brain injury. Short-term hyperoxia has significant effects in upregulation or downregulation of transcription factors relevant to aging such as HIF-1α, nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-kB), and nuclear factor (erythroidderived 2)-like 2 (NRF2) among others. Short-term hyperoxia also has significant effects to increase antioxidant enzymes, and increase telomere length and clearance of senescent cells. Some of the studies have also reported adverse consequences including mitochondrial DNA damage and nuclear cataract formation depending on the dose and duration of oxygen exposure. In conclusion, short-term hyperoxia could be a feasible treatment option to treat age-related disease and to slow aging because of its ability to increase antioxidant enzymes, significantly increase telomere length and clearance of senescent cells, and improve cognitive function, among others. The reported side effects of hyperoxia vary depending on the dose and duration of exposure. Therefore, it seems that additional studies for better understanding the beneficial effects of short-term hyperoxia and for minimizing side effects are necessary for optimal clinical application.

No description available.

No description available.

No description available.

No description available.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23813号 / 医博第4859号 / 新制||医||1059(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 中本 裕士, 教授 花川 隆, 教授 大森 孝一 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

<p> The anaerobic-to-aerobic power ratio is a useful tool to evaluate the strengths and weaknesses of both the aerobic and anaerobic energy systems. The traditional method of calculation has shown this ratio to increase with age in children and to plateau by late adolescence or early adulthood. However, by using the traditional approach, the aerobic component of the ratio is likely highly influenced by anaerobic sources and therefore, may not demonstrate the true proportional changes observed in the respective physiological capacities comprising this ratio with age through childhood and adolescence. The purpose of this study was to examine the age-related development of the power ratio using two new approaches. The lactate threshold (LT) and ventilatory anaerobic threshold (VAT) were identified in 31 competitive male hockey players ranging from 10 to 21 years of age and compared across three discrete age groups. Peak mechanical anaerobic power was obtained from a Wingate test (WAnT) and incorporated into the numerator of the power ratio, while peak mechanical aerobic power was obtained from a modified McMaster all-out progressive test and included into the denominator of the ratio. Mechanical power at the LT and VAT were also identified and integrated into the denominator of the power ratio and results compared to the traditional approach to identify similarities or differences in developmental trends with age. Furthermore, the reliability of the traditional, LT and VAT approaches was examined with retests of six subjects using intra-class correlation analysis and Method Error analysis. When power ratio approaches were compared among discrete age groups, significant differences (P≤0.05) were found between the youngest and oldest age groups for each of the three approaches. Notwithstanding the trend for progressive increases with advancing age group for all approaches, significant correlations with age were only found for the traditional approach (r=0.36). Finally, the VAT approach was the most reliable (r=0.95; ME=0.13) while the LT and traditional approaches demonstrated strong but non-significant test-retest correlations. Results of this study suggest that the LT and VAT approaches may theoretically be more accurate methods of measuring the power ratio than the traditional approach, as there is likely less anaerobic contribution to the denominator of the ratio. Each of the new approaches demonstrates expected age-related trends, and notwithstanding methodological and sample limitations, the VAT in particular, appears to be a more reliable and accurate means of assessing the power ratio compared to the traditional or LT approach.</p> / Thesis / Master of Science (MSc)

Many economically important crop systems exhibit an Age-Related Resistance (ARR) response whereby mature plants become resistant to pathogens they were susceptible to when younger. The signaling pathways and mechanisms of ARR have not been well studied. Arabidopsis displays ARR in response to P. syringae pv tomato (Pst). Several studies provide evidence that intercellular salicylic acid (SA) accumulation is required for ARR and SA acts as a direct antimicrobial agent to limit bacterial growth and biofilm-like aggregate formation. SA accumulation mutants are ARR defective; however, a modest level of resistance is occasionally observed leading to the hypothesis that other compounds contribute to ARR as antimicrobial agents. Previous studies demonstrated that CYP71A13 (a key enzyme in indolic biosynthesis) is expressed during the ARR response. I demonstrated that CYP71A12 functionally compensated for CYP71A13 during ARR, as cyp71a12/cyp71a13-1 mutants were consistently ARR-defective compared to their respective single mutants. I demonstrated that dihydrocamalexic acid (DHCA) accumulated in intercellular washing fluids (IWFs) collected from plants during the ARR response using high resolution mass spectrometry-based profiling. DHCA was detected in IWFs collected from wild-type ARR-competent plants and, was absent in IWFs from ARR-incompetent cyp71a12/cyp71a13 mutants. In vitro DHCA antimicrobial activity against P. syringae was not observed, but exogenous infiltration of DHCA into the leaf intercellular space restored ARR in cyp71a12/cyp71a13 mutants Unlike SA which exhibits direct antimicrobial activity against P. syringae, DHCA does not and instead may affect pathogen virulence in other ways. My research provides evidence that intercellular DHCA contributes to ARR in response to P. syringae in Arabidopsis. Understanding the genes and metabolites contributing to ARR will provide useful information for future crop breeding and genetic modification that will mitigate agricultural losses due to disease. / Thesis / Master of Science (MSc) / During Age-Related Resistance (ARR), mature plants including some crop plants become resistant to pathogens they were susceptible to when younger. How ARR works is poorly understood. My objective was to identify potential antimicrobial metabolites contributing to ARR in Arabidopsis against the bacterial pathogen Pseudomonas syringae. Genetic analyses combined with mass-spectrometry based metabolite profiling demonstrates that two cytochromes P450, CYP71A12 and CYP71A13 contribute to ARR. My research provides evidence that DHCA accumulates in the leaf intercellular space in ARR-competent plants, where it may act to inhibit the bacterial infection process. DHCA has low antimicrobial activity against P. syringae suggesting its mechanism of action is not directly antimicrobial. Importantly, application of DHCA to the leaf intercellular space of cyp71a12/cyp71a13 restored ARR, confirming that DHCA contributes to ARR in Arabidopsis. Understanding ARR will provide useful information for future crop breeding and genetic modification that will mitigate agricultural losses due to disease.

This study examined longitudinal changes in coping and defense mechanisms in an age- and gender-stratified sample of 392 European-American adults. Nonlinear age-related changes were found for the coping mechanisms of sublimation and suppression and the defense mechanisms of intellectualization, doubt, displacement, and regression. The change trajectories for sublimation and suppression showed that their use increased from adolescence to late middle age and early old age, and remained mostly stable into late old age. The change trajectory for intellectualization showed that the use of this defense mechanism increased from adolescence to middle age, remained stable until late midlife, and started to decline thereafter. The defense mechanisms of doubt, displacement, and regression showed decreases from adolescence until early old age, with increases occurring again after the age of 65. Linear age-related decreases were found for the coping mechanism of ego regression and the defense mechanisms of isolation and rationalization. Gender and socioeconomic status were associated with the mean levels of several coping and defense mechanisms, but did not moderate age-related changes. Increases in ego level were associated with increased use of the defense mechanism intellectualization and decreased use of the defense mechanisms of doubt and displacement. Overall, these findings in a European-American sample suggest that most individuals showed development in the direction of more adaptive and less maladaptive coping and defense strategies from adolescence until late middle age or early old age. However, in late old age this development was reversed, presenting potential challenges to the adaptive capacity of older adults.