Caffeine and Apoptosis - Caffeine: Chemistry, Analysis, Function and Effects - page 391

N The term programmed cell death was introduced in 1964, proposing that
cell death during development is not accidental in nature but follows a
sequence of controlled steps leading to locally and temporally defined self-
destruction.
N The term apoptosis had been coined in order to describe the morphological
processes

d n 0 t 2 n g | 2

leading to controlled cellular self-destruction and was first

introduced in a publication by Kerr, Wyllie and Currie in 1972.
N Apoptosis plays an essential role in survival of the organism and is
considered to be an imperative component of various processes including
normal cell turnover, proper development and functioning of the immune
system, multiplication of mutated chromosomes, hormone-dependent
atrophy, normal embryonic development, elimination of indisposed cells
and maintenance of cell homeostasis.
N DNA damage and production of the predominant lesions such as
cyclobutane pyrimidine dimers (CPDs), 6-4 photoproducts (6-4PPs) and
certain other lesions as a result of UV radiation (UVR), ionizing radiation
(IR), oxidative stress, replication or recombination errors as well as from
environmental and therapeutic genotoxins is one of the principal triggers of
apoptosis.
N There are at least two broad pathways that lead to apoptosis, an ''Extrinsic''
and an ''Intrinsic'' Pathway. In both pathways, signaling results in the
activation of a family of Cys (Cysteine) Proteases, named Caspases, that act
in a proteolytic cascade to dismantle and remove the dying cell.
N Improper apoptosis or malfunctioning of individual apoptotic machinery
may cause several human diseases such as cancer and neurodegenerative
disorders as well as several types of autoimmune disorder.
N Unnecessary cell death and unsound regulation of caspase activity are
associated with certain diseases such as Alzheimer's disease, Parkinson's
disease and Huntington's disease.

Key Facts of UV

N

Ultraviolet (UV) radiation is a component of solar radiation.

N

UV radiation levels are influenced by a number of factors: Sun elevation,
latitude, cloud cover, altitude, ozone and ground reflection.

N

Small amounts of UV radiation are beneficial to health, and play an
essential role in the production of vitamin D.

N

However, excessive exposure to UV radiation is associated with different
types of skin cancer, sunburn, accelerated skin aging, cataract and other eye
diseases. There is also evidence that UV radiation reduces the effectiveness
of the immune system.

N

Excessive UV exposure results in a number of chronic skin changes:

a. Cutaneous malignant melanoma: a life-threatening malignant skin

cancer.