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 neurons in the substantia nigra pars reticulata. The reorganization of cellular structures that results from transneuronal degeneration can be seen in Alzheimer's disease. It is hypothesized that anterograde transneuronal degeneration causes the hyperphosphorylation of the tau protein and redistributing those proteins from the axon to the dendrites, which begins the breakdown of routing and sorting mechanisms. Cockayne syndrome results from a mutation in genes that interfere with transcription-coupled repair of nuclear and mitochondrial DNA, replication, and transcription. Neuronal death is predominantly in the cerebellum, but this disease also causes apoptosis in purkinje cells and causes them to have dystrophic dendrites.