![]() ![]() These findings suggest that musical recognition memory is impaired in AD, but the musical lexicon (as assessed by familiarity ratings) is preserved. Nevertheless, the familiarity decision-based ratings of patients was in keeping with controls. In contrast, patients with AD showed impaired learning and recognition of both unfamiliar and familiar melodies with no benefit of familiarity on recognition. Controls also showed improved performance with multiple presentations for both familiar and unfamiliar melodies, without forgetting after 24-hour delay. In keeping with the findings of Bartlett, Halpern, and Dowling (1995), age-matched controls showed better recognition of familiar than unfamiliar melodies. Delayed recognition was tested after 24 hours to evaluate consolidation. Recognition was tested after one and three presentations of the target melodies using a yes/no recognition paradigm. During the initial presentation of the targets, the participant had to decide whether or not the melody was familiar. Seventeen patients with mild to moderate Alzheimer's disease (AD) and 17 age-matched controls were tested. To examine learning and consolidation of melodies, we designed a melodic recognition task involving immediate and delayed recognition of 16 target melodies (8 familiar and 8 unfamiliar). The researchers conclude: “Our results clearly show a novel function of DAO as a promoter of DNA damage-induced senescence, which may provide new insights into the roles of -amino acids in various physiological and pathological processes including senescence, cancer, and aging.The effect of pathological aging on explicit memory is very well documented, but relatively few studies have addressed this issue in the musical domain. In this respect, the study identifies a previously unknown role for DAO. Perhaps it is the overproduction of ROS that causes problems and tips the balance toward cell stress, disease, and aging. For example, low levels of ROS can lengthen the lifespan, and the immune system needs them to fight infection. ROS are not always the bad guys: They can also benefit health. The researchers are cautious about the implications of their findings. In further experiments, the scientists discovered other pathways that help DAO to promote senescence triggered by DNA damage.Ī key factor is the transporter gene SLC52A1, which helps increase levels of the coenzyme flavin adenine dinucleotide (FAD).ĭAO needs a supply of FAD, and SLC52A1 ensures this supply by increasing the availability of vitamin B-2, an ingredient of FAD. The team suggests that this proves that it is DAO’s ability as an enzyme to make ROS that allows it to promote senescence in cells. This version of DAO, however, neither produced ROS nor promoted senescence. ![]() In another experiment, they used a mutant of DAO that stopped it behaving like an enzyme. They found, however, that reducing DAO activity, either with drugs or by silencing its gene, reduced senescence and ROS production. In their more recent investigation, the researchers coaxed cancer cells into senescence by exposing them to low levels of “an anticancer drug that induces DNA double-strand breaks.” However, that “study did not fully explore the direct relationship between DAO and senescence,” they note. In previous work, the Kobe University researchers had discovered that senescence triggers the tumor suppressor molecule p53 and that this activates the gene for DAO. In addition, there is a growing body of knowledge about how aging-related biological changes and diseases involve ROS and senescence. Since then, however, studies have revealed that senescent cells are active in tissue repair, wound healing, embryonic development, and aging.Ī major focus of continuing research is on the various stressors that can trigger cells to enter the irreversible state. ![]() Confined to a senescent state, cells with damaged DNA cannot multiply and give rise to tumors. The recent study adds to a growing understanding of the role of senescent cells in this relationship.Įntering an irreversible state in which it can no longer divide and proliferate does not necessarily diminish a cell’s capacity for change and influence.Įarly research suggested that the main impact of cell senescence on human biology involved protecting against cancer. ROS are important players in the biology of aging and many diseases that tend to increase with advancing age, such as Parkinson’s, Alzheimer’s, diabetes, and many cancers.
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