Wednesday, November 28, 2007
This year the prize in Medicine was divided between 3 scientists, Mario R. Capecchi, Martin J. Evans and Oliver Smithies for their discoveries of "principles for introducing specific gene modifications by the use of embryonic stem cells". (Only 3% of science nobel prize winners have been women- another blog for another day).
Stem cell research is highly controversial at the moment and different countries have different legislations when it comes to research. These laws depend on the religious outlook of that country. Christian countries feel more strongly about banning such research, whereas buddhist or hindu countries are more open.
The reason why this is such a controversial research area is because it requires the use of embryonic cells- using an embryo for research raises a lot of ethical questions. Stem cells research CAN be done using other cells, such as skin cells, which is more acceptable from an ethical standpoint.
The reason why stem cells are interesting, is because they are totipotent and undifferentiated, they are 'uncommited' and can follow any destiny. A stem cell has the potential of becoming an eye or a heart or a toe or a liver. At a certain point a cell will commit itself to these roles which is irreversible.
So why bother with stem cell research if it's so ethically questionable? If you have a defective organ, either a result of cancer or parkinsons, etc etc, wouldn't you want at least an option for treating it? At this point stem cell research is still in early days- and is heavily hindered by legislation. It has been used for treating leukemia using bone marrow transplants. Regardless, this research is important and should be pursued.
This has also become a commercial endeavour for some- some parent store their placenta's in liquid nitrogen immediately after childbirth. Just in case stem cell research advances and it can be used for the child when they get a disease. (this is a luxury item... it costs a lot)
What the 3 Nobel scientists did was to generate genetically modified mice using embryonic stem cell technology. This is a useful tool and technology because it is possible to create a model for human disease caused by defective genes, such as cystic fibrosis. It also has other applications such as in the study of gene therapy. (Gene therapy is the treatment of disease by replacing a defective gene with a good one- using a viral vector... also a controversial subject). Transgenic mice have been used for over 20 years, and it's good that they are getting rewarded for it. The science has been used in countless applications for the study of several diseases. The genomes of man and mouse contain about 22,400 genes- already thousands have studied individually. This provides insight into particular genes relation to development and disease.
Monday, November 12, 2007
The 1918 pandemic flu killed 40 million people in 1 year. Imagine every psychotic diabolical warlord throughout history (Hitler, Milosevic, the Japanese in WWII, Bush, Sadam) rolled into a tiny micro-organism composed of 8 gene segments. So when scientists discovered a woman in the Alaskan permafrost from 1918 who had died of spanish flu- what did they do? They sequenced all the genes and reconstructed it, unleashed it and bought a bunch of property. (No, they aren't THAT clever.)
Using a technique called 'reverse genetics' we are now able to reconstruct viruses de novo with just the genetic components. Basically you throw in the genes into some cells and they assemble into viruses which can later be studied. Terence Tumpey had the honour of doing this in a highly controlled environment in the CDC. The tested the virus on several animal models and are still trying to figure out how the immune system succumbs to the infection. The technique also allows you to mix and match viruses, swapping genes with less potent flu virus genes to compare and determine how some virus parts can contribute to virulence.
What is important about 1918-
pathogenicity- the fact that it can kill so quickly, experiments on mice showed that the virus was 100 times worse that the viruses that circulate in yearly epidemic form.
Transmissability- the virus could spread between humans.
Comparison to H5N1- the current highly pathogenic strain that's circulating at the moment has several similarities to the 1918. Important to know more as H5N1 evolves.
Baron de Rothschild, "When there's blood on the streets, buy property"
Sunday, November 11, 2007
Friday, October 15, 2004
The best antidote to disease
While we fear, and take precautions against, a bio-terrorist attack, nature seems to be taking a stand. Time and again, with its indiscriminate propagation of disease, nature has re-established the hierarchy and demonstrated the extent to which we are at its mercy.
In many Asian nations, the image of the mass slaughter of poultry has become an all too familiar sight. Last year, the world watched anxiously as Hong Kong, mainland China and Canada battled Sars. The disease left nations economically devastated and in a state of widespread panic. With commercial airlines crossing continents every hour, Sars spread across the globe in a matter of days.
It takes only one "good" virus to cause a pandemic. In the same vein, if one country cannot effectively contain and eradicate a disease, the rest of the world will be affected. The technology to control disease exists, but there is a lack of a consensual system of prevention. Outbreaks of bird flu, Japanese encephalitis and dengue fever continue. To take a lesson from Sars, a robust surveillance system, which includes standardised detection methods, can prevent or minimise an outbreak. With the looming threat of the H5N1 bird flu, there is a need to handle the virus before it becomes a pandemic.
The highly pathogenic strain has been found in nine countries, and has claimed 31 lives. At present, humans are not very susceptible. However, as the virus mutates, there is a risk of easy transmission to and between humans. Since its discovery in 1997, the strain has become more indiscriminate, manifesting its lethality in ducks, pigs, dogs and cats. Outbreaks of the H5N1 strain in Thailand last winter led to the culling of millions of fowl to prevent the potential risk to humans.
These outbreaks could be better controlled if we had systematic molecular diagnostics for disease in the veterinary sector. A more efficient system that sources the problem before it escalates is imperative. In Asia, a significant obstacle lies in the varied public health systems, infrastructure and resources. International conventions that standardise every aspect of disease detection are the only way to make a credible effort to reconcile the present discrepancies.
The UN Food and Agriculture Organisation and the World Organisation for Animal Health, meeting in Bangkok, concluded that bird flu is a crisis of global importance. They said that major investments are needed for surveillance, early warning, detection and reporting. They have published recommended tests for the detection of diseases such as influenza, and are promoting standardised diagnostic testing. The challenge is how to execute control programmes. These two bodies should take the lead in implementing the standardisation of molecular tests, beginning by evaluating and validating the system. Diagnostic methods that demonstrate speed, simplicity, accuracy and cost effectiveness can enhance the global surveillance of infectious diseases. In fact, such methods do exist. The limitations of developing nations should be taken into account; benefits such as trade advantages can encourage the use of standardised methods and, in the case of avian flu and the poultry industry, improve a country's reputation as a top food exporter.The most recent victim of bird flu was Kanda Srileung-On, a nine-year-old girl from Thailand. She was diagnosed with the H5N1 virus only hours before her death. There have also been suspected cases of human-to-human transmission, and these took more than a week to confirm. There needs to be a greater sense of urgency on the surveillance front. Technology makes it possible to diagnose and confirm bird flu within 24 hours. In a crisis of global importance, there is a dire need to improve international surveillance and prevent a catastrophic outbreak.
We live in an arts driven society and most people have very little understanding of what means to be involved in science. Most people will draw a blank when I tell them that I work on influenza and I know after 10 seconds of awkward silence to quickly change the topic to fashion, music, movies or art. So with this blog I will aim to write about things in the world of science that I find remarkable, innovative, conceptually challenging and generally important.