Artificial organ a stationary power supply or other stationary resources such as filters or chemical processing units. (Periodic rapid recharging of batteries, refilling of chemicals, and/or cleaning/replacing of filters would exclude a device from being called an artificial organ.) Thus, a dialysis machine, while a very successful and critically important life support device that almost completely replaces the duties of a kidney, is not an artificial organ. Constructing and installing artificial organs, an extremely research-intensive and expensive process initially, may entail many years of ongoing maintenance services not needed by a natural organ.: The use of any artificial organ by humans is
Transneuronal degeneration in the fornix, mammillary bodies, and contralateral cerebellum. It has recently been shown that transneuronal degeneration can also be caused after respiratory chain-deficient neurons develop from "de novo" mitochondrial DNA mutations, which are normally associated with mammalian ageing. The respiratory chain-deficient neurons have adverse effect on normal adjacent neurons, inducing death by means of transneuronal degeneration. Transneuronal degeneration in these cases is accelerated during the ageing process since other cellular maintenance systems are already damaged as well as in the presence of mitochondrial disease, where non-neuronal cells like glial cells and astrocytes also have respiratory chain deficiency. This also means