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Senescent
Senescence () or biological aging is the gradual deterioration of functional characteristics in living organisms. The word ''senescence'' can refer to either cellular senescence or to senescence of the whole organism. Organismal senescence involves an increase in death rates and/or a decrease in fecundity with increasing age, at least in the latter part of an organism's life cycle. Senescence is the inevitable fate of almost all multicellular organisms with germ-soma separation, but it can be delayed. The discovery, in 1934, that calorie restriction can extend lifespan by 50% in rats, and the existence of species having negligible senescence and potentially immortal organisms such as '' Hydra'', have motivated research into delaying senescence and thus age-related diseases. Rare human mutations can cause accelerated aging diseases. Environmental factors may affect aging – for example, overexposure to ultraviolet radiation accelerates skin aging. Different parts of the body may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Senescence
Cellular senescence is a phenomenon characterized by the cessation of cell division. In their experiments during the early 1960s, Leonard Hayflick and Paul Moorhead found that normal human fetal fibroblasts in culture reach a maximum of approximately 50 cell population doublings before becoming senescent. This process is known as "replicative senescence", or the Hayflick limit. Hayflick's discovery of mortal cells paved the path for the discovery and understanding of cellular aging molecular pathways. Cellular senescence can be initiated by a wide variety of stress inducing factors. These stress factors include both environmental and internal damaging events, abnormal cellular growth, oxidative stress, autophagy factors, among many other things. The physiological importance for cell senescence has been attributed to prevention of carcinogenesis, and more recently, aging, development, and tissue repair. Senescent cells contribute to the aging phenotype, including frailty syndrom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallmarks Of Aging
The hallmarks of aging are the types of biochemical changes that occur in all organisms that experience biological aging and lead to a progressive loss of physiological integrity, impaired function and, eventually, death. They were first enumerated in a landmark paper in 2013 to conceptualize the essence of biological aging and its underlying mechanisms. Overview Over time, almost all living organisms experience a gradual and irreversible increase in senescence and an associated loss of proper function of the bodily systems. As aging is the primary risk factor for major human diseases, including cancer, diabetes, cardiovascular disorders, and neurodegenerative diseases, it is important to describe and classify the types of changes that it entails. The nine hallmarks of aging are grouped into three categories as follows: Primary hallmarks (causes of damage) * Genome instability * Telomere shortening * Epigenetic alterations * Loss of proteostasis Antagonistic hallmarks (re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aging
Ageing ( BE) or aging ( AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. In a broader sense, ageing can refer to single cells within an organism which have ceased dividing, or to the population of a species. In humans, ageing represents the accumulation of changes in a human being over time and can encompass physical, psychological, and social changes. Reaction time, for example, may slow with age, while memories and general knowledge typically increase. Ageing increases the risk of human diseases such as cancer, Alzheimer's disease, diabetes, cardiovascular disease, stroke and many more. Of the roughly 150,000 people who die each day across the globe, about two-thirds die from age-related causes. Current ageing theories are assigned to the damage concept, whereby the accumulation of damage (such as DNA ox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negligible Senescence
Negligible senescence is a term coined by biogerontologist Caleb Finch to denote organisms that do not exhibit evidence of biological aging (senescence), such as measurable reductions in their reproductive capability, measurable functional decline, or rising death rates with age. There are many species where scientists have seen no increase in mortality after maturity. This may mean that the lifespan of the organism is so long that researchers' subjects have not yet lived up to the time when a measure of the species' longevity can be made. Turtles, for example, were once thought to lack senescence, but more extensive observations have found evidence of decreasing fitness with age. Study of negligibly senescent animals may provide clues that lead to better understanding of the aging process and influence theories of aging. The phenomenon of negligible senescence in some animals is a traditional argument for attempting to achieve similar negligible senescence in humans by technologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydra (genus)
''Hydra'' ( ) is a genus of small, freshwater organisms of the phylum Cnidaria and class Hydrozoa. They are native to the temperate and tropical regions. The genus was named by Linnaeus in 1758 after the Hydra, which was the many-headed beast defeated by Hercules as when the animal had a part severed, it would regenerate much like the hydra’s heads. Biologists are especially interested in ''Hydra'' because of their regenerative ability; they do not appear to die of old age, or to age at all. Morphology ''Hydra'' has a tubular, radially symmetric body up to long when extended, secured by a simple adhesive foot known as the basal disc. Gland cells in the basal disc secrete a sticky fluid that accounts for its adhesive properties. At the free end of the body is a mouth opening surrounded by one to twelve thin, mobile tentacles. Each tentacle, or cnida (plural: cnidae), is clothed with highly specialised stinging cells called cnidocytes. Cnidocytes contain specialized s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telomere
A telomere (; ) is a region of repetitive nucleotide sequences associated with specialized proteins at the ends of linear chromosomes. Although there are different architectures, telomeres, in a broad sense, are a widespread genetic feature most commonly found in eukaryotes. In most, if not all species possessing them, they protect the terminal regions of chromosomal DNA from progressive degradation and ensure the integrity of linear chromosomes by preventing DNA repair systems from mistaking the very ends of the DNA strand for a double-strand break. Discovery In the early 1970s, Soviet theorist Alexei Olovnikov first recognized that chromosomes could not completely replicate their ends; this is known as the "end replication problem". Building on this, and accommodating Leonard Hayflick's idea of limited somatic cell division, Olovnikov suggested that DNA sequences are lost every time a cell replicates until the loss reaches a critical level, at which point cell division e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel movements. While these symptoms may indicate cancer, they can also have other causes. Over 100 types of cancers affect humans. Tobacco use is the cause of about 22% of cancer deaths. Another 10% are due to obesity, poor diet, lack of physical activity or excessive drinking of alcohol. Other factors include certain infections, exposure to ionizing radiation, and environmental pollutants. In the developing world, 15% of cancers are due to infections such as '' Helicobacter pylori'', hepatitis B, hepatitis C, human papillomavirus infection, Epstein–Barr virus and human immunodeficiency virus (HIV). These factors act, at least partly, by changing the genes o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeostasis
In biology, homeostasis (British English, British also homoeostasis) Help:IPA/English, (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physics, physical, and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium and calcium ions, as well as that of the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in the optimal conditions, and equilibrium is maintained by many regulatory mechanisms: it is thought to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aging-associated Diseases
An aging-associated disease (commonly termed age-related disease, ARD) is a disease that is most often seen with increasing frequency with increasing senescence. They are essentially complications of senescence, distinguished from the aging process itself because all adult animals age ( with rare exceptions) but not all adult animals experience all age-associated diseases. The term does not refer to age-specific diseases, such as the childhood diseases chicken pox and measles, only diseases of the elderly. They are also not accelerated aging diseases, all of which are genetic disorders. Examples of aging-associated diseases are atherosclerosis and cardiovascular disease, cancer, arthritis, cataracts, osteoporosis, type 2 diabetes, hypertension and Alzheimer's disease. The incidence of all of these diseases increases exponentially with age. Of the roughly 150,000 people who die each day across the globe, about two thirds—100,000 per day—die of age-related causes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ann Pouder
American supercentenarians are citizens or residents of the United States who have attained or surpassed 110 years of age. , the Gerontology Research Group (GRG) had validated the longevity claims of 782 American supercentenarians. As of , it lists the oldest living American-born person as Spanish emigrant María Branyas Morera (born in San Francisco, California on March 4, 1907), aged . The oldest American resident is listed as Edie Ceccarelli (born in Willits, California on February 5, 1908), aged . The longest-lived person ever from the United States is Sarah Knauss, of Hollywood, Luzerne County, Pennsylvania, who died on December 30, 1999, aged 119 years and 97 days. 100 oldest known Americans Below is a list of the 100 longest lived American supercentenarians according to the GRG and reliable sourcing. Biographies Ann Pouder Ann Pouder (née Ann Marie Alexander; April 8, 1807 – July 10, 1917) was one of the first modern recognized supercentenarians, living to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Disease
Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, heart failure, hypertensive heart disease, rheumatic heart disease, cardiomyopathy, abnormal heart rhythms, congenital heart disease, valvular heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis. The underlying mechanisms vary depending on the disease. It is estimated that dietary risk factors are associated with 53% of CVD deaths. Coronary artery disease, stroke, and peripheral artery disease involve atherosclerosis. This may be caused by high blood pressure, smoking, diabetes mellitus, lack of exercise, obesity, high blood cholesterol, poor diet, excessive alcohol consumption, and poor sleep, among other things. High blood pressure is estimated to account for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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