Disequilibrium

Disequilibrium

New research sheds light on attention deficit and hyperactivity syndrome.

neuron growth cone

When a child is born their brain already contains a finely sculpted network of brain cells connected in a predetermined pattern. This is achieved by balancing the rate of brain cell growth against cell death. To understand this researchers studied SORCS2, a gene that intriguingly has opposing roles in different parts of the brain. The product of this gene exists in two forms: a single long protein that regulates growth at the hand-like extremities (stained orange) of the pictured cell, and a composite of two linked segments of the protein which together control cell death. Mice lacking this gene exhibit traits very similar to attention deficit and hyperactivity disorder (ADHD) such as increased physical activity that is calmed by amphetamine drugs. Such a clear cut biological pathway – from gene to protein to cells to symptoms – suggests that disrupting the balance between brain cell growth and death underpins attention deficit disorders.

 

How to be a Woman

How to be a Woman

This piece was inspired by Dean Burnett’s Beach Body article  and Caitlin Moran’s book ‘How to be a Woman‘.

normal female with two x chromosomes

How to be a woman (scientific guide):

Have no Y chromosome*
Be over sixteen
Have the full set of functional internal organs including a brain
Other options are flexible
There you have it – you are a woman.

* More accurately lack a testes determining factor (tdf), normally resident on the Y-chromosome.  Exceptions include  when the tdf is faulty leading to an XY female or when the gene is relocated on a different chromosome giving an XX male. 

copyright Julie Webb 19/06/14

Cell Recognition

How can certain cells recognise other certain types of cells? A question from Adam Ashing.

Good question Adam. Cells recognise each other by the molecules that stick out of their outer surface layer (the membrane). These cell surface markers are proteins, lipids (fat) and carbohydrates or any combination of these molecules.

The rhesus factor of blood cells is an example of a surface protein which other cells recognise. The A and B blood groups are also cell surface molecules although they  differ from rhesus in that they are both carbohydrates. Rhesus negative and blood group O is the absence of these molecules.

Cell recognition is very important in the immune system because immune cells need to tell the difference between your own cells (self) and foreign cells (pathogens). Bacteria often have a lipid molecule with sugar chains attached (a ‘lipopolysaccharide’) on their surface. When our immune cells recognised this molecule they act very quickly to destroy the invading bacteria before they can multiply and cause us harm (pictured above).

Releasing molecules out of the cell is another way that cells recognise each other. Some immune cells have special proteins on their cell surface that helps them to recognise foreign cells. Recognition acts as a trigger for the cell to make more of these cell surface proteins.  The newly made proteins are shorter than the original – they lack the bit that attaches them to the cell surface, so instead of being on the surface they end up outside the cell.

These proteins are antibodies: they attach to the foreign cells but they also attach to each other and form clumps. Clumping stops the foreign cell from multiplying or entering host cells. A separate type of immune cell recognise the clumps and engulfs them, pacman style, to destroy the invader.

Helminthic Therapy – shall I go and eat worms?

Today’s question, by Caroline, is asking whether eating parasitic worms can protect against asthma, diabetes, gut problems, and even multiple sclerosis.

Shall I go and eat worms?

Whipworm

Don’t worry I’m not feeling like Johnny-no-mates today, this question refers to a pub discussion a couple of weeks back about using parasitic worms as therapy for various diseases. The worms in question, helminths, are a broad group of species some of which live in the gut of their host and feed off the food they are ingesting or alternatively the host’s blood. Parasitic worms infect about a quarter of the worlds populations and although infection is not usually fatal the malnutrition or anaemia that follows is often debilitating. In children the situation is more serious since the worm can affect intellectual development and growth.

So why would someone deliberately infect themselves with parasitic worms? Well there is evidence that they help with certain immune diseases, particularly those of the gut such as Crohn’s syndrome, ulcerative colitis and inflammatory bowel disease but asthma, multiple sclerosis and type 1 diabetes also improve. These are all ailment that involve some aspect of inflammation where the immune system becomes over-zealous to a relatively harmless trigger.

Immune switch

The most likely explanation for how the worms reduce inflammation lies in their influence on the immune system. There is an immune ‘stem cell’ that, when it matures, can become one of two types of cell: type 1 which promotes inflammation and allergy or type two which fights parasitic infection.  Infection with worms increases the number of type two cell as the immune system tries to rid the body of the parasites.  Consequently the number of type 1 cells decreases leading to a reduction in inflammation and improvement of the immune based diseases.

Scarred

So should I take them for asthma? Inflammatory diseases usually involve some irreversible scarring which eventually leads to health problems. Asthma, for example, is not just a series of  transient attacks that are alleviated by an inhaler, the scarring caused by inflammation leads to permanent  damage and constant problems with breathing in later life.  Scarring is also a feature of inflammatory disease of the gut and leads to permanent problems with digestion. So I should consider anything which prevents inflammation, no matter how odd.

Unlicensed

Before you rush off to your doctor I should tell you these worms are not available from GP’s just yet because they are not a licensed therapy.  And this is my quandary, because they are available on the internet. After a brief health questionnaire  and a fee, you, or me, could be host to a worm or two or twenty.

If time was not an issue then the course of action would be clear – don’t take them because it is not clear they will work or worse, be harmful to health (see the table below for more details). But time is an issue and the sooner I take something that will probably work and is probably not very harmful, the less scarring on my lungs (which I know will be harmful).

A recent study (1) has identified the specific protein in the worms that causes the immune switch away from type 1 inflammatory cells. That is exciting news because it opens the way for more conventional pill based therapy without the need for whole worms. It will take time: ten, fifteen, maybe even twenty years but I’m willing to wait because if I’m truly honest the idea of swallowing live worms is just too gross.  I’d rather wheeze.

Table 1. Health therapy options – licensed through pharmaceuticals company or bought from the internet.

Licensed Unlicensed
Taken under medical supervision Not taken under medical supervision but in the UK you can go to your doctor if something goes wrong
Medical claims on the packaging regulated: all claims must be backed by strong scientific evidence Claims made on the internet or by word of mouth not always substantiated with data or strongly underpinned by law. Little or no regulation
Monitored for false or exaggerated claims Exaggerated claims frequent, little monitoring
All side effects observed  during trials listed Side effects not clear
Medical trials done in large groups to examine safety and identify side effects. Data taken from smaller medical trials in medical literature. Indicative but not comprehensive. Side effects not written up and shared with the scientific or medical community.
Medical trials give indication of whether it works and who it works for. Safety issues expressed but vulnerable groups not prevented from obtaining it. Not clear who should take what.Not clear if it works.
Expensive, drug companies charge a lot for new treatments Relatively cheap although more expensive than a UK prescription
Takes a long time 10-20years Have it now

Thanks to Caroline Bell for the question.

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3584281/

Whip worm image from Wikimedia: http://commons.wikimedia.org/wiki/File:Trichuris_trichiura.jpg

International Day of Persons with Disabilities

Smiles All Round

This article is to celebrate International Day for Persons with Disabilities and is dedicated to my beautiful niece Eilidh and her eternally determined fabulous mum Sonia. Read their blog: All Born In.

smiles all round

A child’s smile is one of life’s greatest joys but here it’s being used to measure the success of a pioneering therapy for cerebral palsy – a condition caused by damage, during early childhood, to those areas of the brain that control muscle movement and balance. There is currently no cure although treatments like physiotherapy can help.

Researchers gave this child, who was previously unable to smile or respond to the world around him (top left), a blood infusion – like a transfusion but using his own blood taken from his umbilical cord. This ‘cord blood’ is rich in stem cells, which have the capacity to replace damaged tissue. The boy’s subsequent improvement was remarkable, much better than expected with physiotherapy alone.

He is the first child ever to receive this new treatment and many questions about its safety and effectiveness remain to be answered before it becomes a mainstream treatment.

Journey Inside a Brain

Journey Inside a Brain

Brain 4

Ever wondered what the inside of a brain looks like? These images come from a 3D video of just that. You can see the video at The Cell: an Image Library,  here.

The long stringy projections of the neurons are green and where the projections from different cells meet are red. In blue are special proteins called microtubules (because they form very small tubes) which are thought to hold our memories.

Poor Clementine – a question from Dawn Lucas

Poor Clementine

What happens when osmosis attacks….

Q: How do you bottle clementines as per recipe in sugar, water and brandy without them turning into prunes? I’m suspecting osmosis couldn’t resist them and has snuck into the jar too? I’m gutted as it took ages to peel and sort them.

A: Use a different amount of sugar – you want the water levels inside and outside of the fruit to be almost the same. If the sugar concentration of the preserving juice is too high then all the water moves out of the clementines  and the poor thing shrivels up. If the sugar concentration is too low then the water rushes in, the cells burst and the fruit disintegrates. Since they seem to have shrivelled you could try adding sterile water bit by bit until they swell up again.

You are right about osmosis causing the problem – nature is always trying to equalise concentrations but here the water can move freely in and out of the cells while the sugar can’t because of the cell membranes. The water moves in or out of the cells without a corresponding opposite movement of sugar.

For some fruits, like apples and cherries, the sugar concentration is not so critical because they have tough fibres that keep the fruit’s  (but not cell’s) shape intact in the face of osmosis. Clementine’s are apparently more susceptible.

Thanks to Dawn Lucas for the question and the image.