Loops

Happen to listen to another show from Radio lab. Its an amazing show. I love it a lot. This time it was about loops.

There are several segments in the show. The one which enticed me most was a short discussion on 'Zero'. Think about it, zero (0) is the most familiar loop of all. Although we (at least I) never looked at it in that way. Robert Krulwich's explanation of how did ancient Indians came up with the idea of zero was funny "they drew a circle around nothing". Well, its funny but deeply philosophical. How could one conceive the idea of nothing? As ancient Greek philosophers asked " How can nothing be something?".

Zero: The most mystical number, a count of nothingness. And it got the perfect symbol also "0", a loop, something which doesn't have a beginning or an end. It is not surprising that this concept came from Indian philosophy. The theme about repetition is a 'repeating theme' in Hindu philosophy. The repeating cycles of births and deaths of living beings. The repeating cycles of creation and destruction of the universe etc... But the ultimate purpose of life is getting out of the loop. Once you get detached from material world you will escape from the maya (illusion) of the loop and achieve nirvana, the ultimate goal of life.

In addition to philosophical tones loops has some significance in practical psychology too. One of the key concept in transactional analysis is life script. Most individuals write a script on their life based on early childhood experience. Most of us became slaves of this self created script. It happens in cycles. Even before we take up an endeavor we know the out come at subconscious level, just like the scriptwriter who knows the climax of a movie. Our body and mind gradually enact this life script (without the conscious knowledge). That is why in lives of many individual the success or failure became a repeating pattern. For a more fulfilling life the goal should be to lead a script less life. I found an interesting read on it (http://www.relationships-explained.com/pages/Life-script.html).

As a biologist one loop that I am interested in is the case of stem cells. These are naturally immortal cells with ability for asymmetric division. There is another type of immortal cells, which are very popular and notorious, cancer cells. Cancer cells are those cells which has this boon of immortality. They achieve this by sabotaging the normal mechanisms present in cells which prevent the uncontrolled division of cells. It is a pathological condition because cancer cells are selfish and do not care about their neighbors. It grows in an uncontrolled fashion and cause havoc in normal environment of the tissues.

On the contrary, stem cells are naturally immortal. They are needed to replace the cells which are lost from the body due to various reasons (For Eg: growth of hair, healing of wound, continuous supply of blood cells....). They undergo the so called asymmetric division. Cells usually divide into two daughter cells. This division will produce two types of cells, one which exactly resemble the mother cells (self renewal) and other which is different from mother cells. The cell which is different from mother cells are the one that eventually develop to new type of cells to replace the old one (the process called differentiation). But the cell which is the exact copy of the mother cells remain as stem cells (so that when ever needed it can differentiate again). There is a hypothesis called immortal strand hypothesis, which suggests that the mother cells always retain one particular copy of the DNA strand to itself, so that it is safe from errors that may occur while copying it (It is not tested/proven in all adult stem cells). Anyway, if it is true the stem cells are immortal because they are in loop. They always remain in same location (so called "niche") to maintain their identity. Its the daughter cells which escape from the loop which form cell types which are diverse and more of practical use. Its the fate of the stem cells, but in this case this fate is good for the organism. I don't know what those stem cells might feel. Bored! frustrated!. Lest they have the feeling!

Image Courtesy: http://njms.umdnj.edu/gsbs/stemcell/scofthemonth/CSCsci.htm