Monday, February 21, 2011

A Landmark Study by an Old Friend in India

Dear friends,
Not only I but all those who have known Dr. Santasabuj Das during his stay at SGPGI, Lucknow, would be proud of his landmark findings that have just appeared in a very prestigious journal, Proceedings of National Academy of Sciences (PNAS). Going down memory lane, I can recall those times very well, when I just had started as a Ph.D. student in the Department of Gastroenterology and was going through rotations in various laboratories in the Department of Immunology, a major collaborating department at the Institute, where most of GI fellows and Ph.D students used to be trained for their laboratory based projects those days. Dr. Santasabuj Das (fondly known as Dr. Das) also had started his postdoctoral medical residency in the Department of Immunology at the same time. I guess everyone known to him during that time would agree with me in recalling him as a voracious reader, often found lost in books and journals in library reading almost everything, little-shy, too inquisitive about everything while in seminars and classes, and may be always restless (may be it was constantly ongoing quest for knowledge inside him that often appeared on his face). He soon realized that his destiny was in laboratory science and left for NCBS and subsequently to the US, to learn more and more about what he had always been passionate about. Now after so many years later, here he is back with such a great work, so much relevant to the people in India, Bangladesh, and many other tropical countries.

We all have heard of typhoid fever, which is a common illness in tropical countries. It is caused by bacteria Salmonella Typhi. Please do not mistake it with Salmonella Typhimurium which is more commonly found bacteria and causes enteric diseases, also a common cause of food adulteration in western countries where they use packed food especially vegetables and eggs as opposed to tropical countries where still fresh and seasonal vegetables are in fshion mainly due to lack of uniturrupted power supply and equipments to  freeze foods. Anyways, in the age of antibiotics, management of typhoid is not a big problem, but if not treated in time or infected with a version of bacterium which is resistance for commonly used antibiotics, it can lead to serious consequences. There is another interesting angle to Salmonella Typhi infection – 1% of all those who have ever been infected with Salmonella Typhi become chronic career. It means 1% of all infected people will still harbor bacteria for years and decades though with no symptoms. This bacteria travells all the way to the gallbladder where it finally makes it home as it gets to eat its favourite foods available in the form of bile salts and resides silently and does not apparantly harm to the person. There is a famous study conducted in NewYork City in early 20th Century, where a lady known as Mary Mallon, more notoriously known as "Typhoid Mary" who was  a chronic career Salmonella typhi, infected ~53 people.  

Anyways, I also have some connection with all this, as a major part of my Ph.D. thesis work was focused on the role of chronic Salmonella infection in gallbladder cancer. There are a group of physicians and scientists in India (where gallbladder cancer is more frequently found), including Dr. Gourdas Choudhuri (my Ph.D. advisor) and Dr. V. K. Kapoor at SGPGI, Lucknow, and Dr. V.K. Shukla at Banaras Hindu University, believe and have some published evidences that it is chronic infection of gallbladder with Salmonella Typhi, which along with inflammatory events due to long term persistence of gallstones (which is another associated factor with gallbladder cancer) that results in early carcinogenic events in the gallbladder. However, I must say that this hypothesis needs more solid evidences and may be a more direct demonstrations in an animal model which has been so far not feasible by all available laboratory methods. However, coming back to Dr. Das’ contribution, in his report he has very nicely described a role of an adhesion protein present in Salmonella, which was not known so far, could be very helpful in designing a new type of vaccine which can protect against Salmonella infection much more effectively than existing vaccines.

By the way, this article has also been selected by "Nature" as one of the most important studies came this week: 

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