Continuing my series of articles breaking down articles published in The Lancet, here is a look at new research which shows promising results for stem cell treatment post- heart attack. Check it out here:
http://www.thelancetstudent.com/blog/healing-broken-heart
Tuesday, 28 February 2012
Wednesday, 8 February 2012
Beating Stress
Everybody experiences stress, from the
small things, such as missing the train to work, to rather more difficult
situations, such as dealing with a car crash. The way that we deal and respond
to stress however, can vary from person to person. It is estimated that 10% of
people in the UK will experience Anxiety and Mixed Depressive Disorder at some
point in their lives. So why is it that our responses to stress can be so
different?
Anxiety disorders (such as
post-traumatic stress disorder, amongst others) can be exceptionally
debilitating in everyday life. People with anxiety disorders are also thought
to pay more attention towards negative or threatening things in the environment
around them and have been linked with a variation in the Serotonin Re-uptake
Transporter Gene (5-HTTLPR).
Serotonin (also known as 5-HT) is a
common and important neurotransmitter in the brain that is strongly linked with
mood. The short version (s allele) of the 5-HTTLPR gene causes lower production
of the Serotonin Transporter, which removes serotonin molecules from the
synapses between nerve cells after they have been used for signalling. Thus,
having the s allele will cause increased levels of serotonin in the synapse,
due to slower re-uptake.
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| Serotonin is a monoamine neurotransmitter. |
A study published last month, has looked into effects of the s allele on attention bias. They split their participants into two groups, with roughly a 50/50 split of people with the s allele and the long (l) allele. The groups were then subjected to an attention bias test, before undergoing attention bias modification (ABM). ABM is an experimental technique that is used to alter a person’s attention bias, either more positively or negatively, reflecting encounters with positive and negative stimuli in our everyday lives.
Participants with the s allele were
more sensitive to ABM, scoring higher in both positive and negative attention
bias tests after the ABM, but were especially sensitive to negative stimuli.
This result suggests a role for 5-HTTLPR as an ‘adaptability gene’, ie, not a
gene that would affect us all the time, but given the right stimuli,
could be responsible for changes in the way our brain works that would affect
our response. In practical terms this shows that people with anxiety disorders
may be predisposed to dealing poorly with stressful life events, but that they
may also thrive in an environment that is supportive.
It also shows the possible importance
of Gene/ Environment interactions (GxE). This is an area for debate in current
research but it seems clear that in some cases it is not simply the genes you
possess that is the most important factor, but how they interact with the
external stimuli that we encounter.
This paper suggests the possibility of
serotonin- reducing drugs possibly being effective in an anti- anxiety setting.
Clearly we will need further research to find an effective treatment.
Comment:
Free PubMed Article:
Picture, Wikipedia.org
http://www.google.co.uk/imgres?q=serotonin&hl=en&safe=off&sa=X&biw=1366&bih=667&tbm=isch&prmd=imvns&tbnid=0LoxSnjszNZUyM:&imgrefurl=http://en.wikipedia.org/wiki/File:Serotonin-3D.png&docid=uRd9BEu4ZdfrfM&imgurl=http://upload.wikimedia.org/wikipedia/commons/5/53/Serotonin-3D.png&w=2331&h=2016&ei=jwsXT6S7EYPoOZ3VmYcE&zoom=1&iact=hc&vpx=984&vpy=362&dur=3105&hovh=209&hovw=241&tx=135&ty=120&sig=115565233929553937633&page=1&tbnh=137&tbnw=165&start=0&ndsp=21&ved=1t:429,r:19,s:0
Thursday, 2 February 2012
Suicide rates in England and Wales
I have another blog on The Lancet Student on a study showing that recent changes in mental healthcare in England and Wales has brought about a decline in suicides. A topical paper given the threat of cuts and reform to the NHS. Enjoy.
my blog:
the paper:
a comment in The Lancet:
this paper is in the news:
http://www.bbc.co.uk/news/science-environment-16816344
Wednesday, 25 January 2012
Getting better: how do we test new cancer treatments?
Another blog on The Lancet Student. Check it out.
http://www.thelancetstudent.com/blog/getting-better-how-do-we-test-new-cancer-treatments
Friday, 13 January 2012
Tuesday, 8 November 2011
Growing Better
For years now Stem Cell research has been one of the hotter topics in new medical research. Certainly the media portrays stem cell research as the next miracle- working stage of medicine where we will be able to grow new livers cure all kinds of diseases and disorders.
But how close are actually to using stem cell research in practical healthcare?
In a letter published by Nature this week, a research group in New York, NY has given us a good insight into how far stem cell research has come. They have focused on using stem cells to treat Parkinson’s Disease, a well-known genetic disorder caused mainly by the death and degeneration of Dopaminergic Neurons in the Substantia Nigra. Dopamine is a neurotransmitter that is associated with a large number of functions, but is important in controlling movement. As Dopaminergic neurons degenerate this effects our control over our movement, hence the shaking symptoms associated with Parkinson’s.
The objective of the research is to see how effective using stem cells to grow new Dopaminergic neurons might be. This team took Pluripotent Stem Cells (PSC, the type of stem cell that can grow into anything) and exposed them to Wingless (WNT) and Sonic Hedgehog signalling molecules (SHH, also not a joke!) which directed the cells into becoming Mid-Brain Dopaminergic neurons. After 25 days of growth they had neurons that could be used in vivo (in actual living animals, as opposed to in vitro- in the lab).
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| Pluripotent Stem Cells: the type that can grow into almost any cell in the body |
The study then used lesioned Mice and rats to simulate the effects of Parkinson’s (mice with part of their brain removed, this can then simulate Parkinson’s in animals). They reported that the subjects showed improved motor skills and less akinesia (uncontrolled shaking) in tests, suggesting that the implanted stem cells were improving symptoms associated with Parkinson’s.
All in all this is a remarkable and interesting experiment. They have shown it is possible to grow Dopaminergic neurons, maintain them for months in a living thing and even that they could be planted into monkeys. There is promise here that this treatment may also help to relieve the symptoms of Parkinson’s. Before we get too excited however there are still clear limitations: there are still safety concerns with Stem cells and we still have yet to try this in humans, a huge leap in research that I suspect will have to overcome massive ethical questions before it can go ahead.
Still, this experiment is one of many that suggests, one day, we might be able to grow ourselves better.
original paper:
picture (from Popsci.com)
Tuesday, 11 October 2011
Free to do what I want! …or not?
You’re standing in a department store and you’re shopping for clothes. There’s a big selection. Eventually you choose a new pair of Levi jeans, you had a lot of choice though.
Or did you?
What if the choices that you think you make have actually been made for you, several seconds before by your brain? What if, in fact, you had no Free Will?
Free Will is a big philosophical question, with passionate arguments on either side. Most people would assert that in their everyday lives they experience free will as they choose what they eat, who they talk to, how to get to work and what glass of wine they will have with dinner. But as our knowledge of how the brain works expands, Neuroscience may be slowly shattering the idea that we have control over our own lives.
A study done by Haynes and his group at the Bernstein Centre for Computational Neuroscience in Berlin has posed some challenging questions on this subject. Subjects were placed in an fMRI machine (a type of brain scanner that measures brain activity by tracking minute changes in blood flow) and shown a series of random letters. They were told to press a button in front of them whenever they felt like it, with either their left or right hand and to remember which letter was shown when they did.
Looking at the brain activity of subjects, Haynes was able to see that the conscious decision to press the button was made a second before the act, which seems reasonable. But he also found a pattern of brain activity that preceded the decision by as much as seven seconds. It seems that before the subjects were aware they had made a choice, their brains had made it for them.
These seem rather unsettling findings. The idea that our brains are making all our decisions for us is not a pleasing one. There have been other experiments such as this but it is too early to say that Neuroscience has killed our notion of free will. Future experiments will have to establish fully that these early pattern of brain activity really do result in unconscious decisions, rather than simply being part of a wider parallel decision making processes. Future studies will also need to apply simple lab tests to the complex decisions we make in real life.
Neuroscience hasn’t set out to destroy our long (and proudly) held view that as humans free will makes us special. But it is certainly asking some fascinating questions.
link to paper via Nature Neuroscience:
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