Friday, 29 March 2013

Blood Groups

Stemming from the post 'Blood Donation'; this post looks at the different blood groups that are present in human bodies and also some UK statistics. There are four different blood groups in the ABO blood system (A, B, AB and O (originally C)) which are each split into two groups via the Rhesus system where Rhesus is positive and without is negative i.e. A Rhesus (+) and A-.

A slice of history: "early attempts at blood transfusions, as far back as 1666, seemed to have been very successful, but when a French patient died unexpectedly during a procedure in 1668 all efforts were halted" (NHS Blood and Transplant: Blood Groups Leaflet).

But what segregates these different groups from each other? It is all down to the antigens (markers on the surface of red blood cells) and the antibodies (part of the specific immune response secreted by B effector cells to cluster 'foreign material' to be destroyed by macrophages) present in the blood. Between the blood types there are three types of antigens (A antigens, B antigens and Rhesus antigens) and two types of antigens (anti-A and anti-B).

A+ blood contains anti-B antibodies and red blood cells with A antigens and Rhesus antigens.
A- blood contains anti-B antibodies and red blood cells with A antigens but no Rhesus antigens.
B+ blood contains anti-A antibodies and red blood cells with B and Rhesus antigens.
B- blood contains anti-A antibodies and red blood cells with B but no Rhesus antigens.
AB+ blood contains no antibodies and red blood cells with A antigens, B antigens plus Rhesus antigens.
AB- blood contains no antibodies and red blood cells with A antigens, B antigens but no Rhesus antigens.
O+ blood contains anti-B and anti-A antibodies but red blood cells with no A or B antigens, just Rhesus antigens.
O- blood contains anti-B and anti-A antibodies with no antigens on the surface of the red blood cells.

These properties of the different blood groups are responsible for how they can be used and to whom they can be used by. If anti-A antibodies come into contact with A antigens they will attack the red blood cells and destroy them. This is the same reaction if anti-B antibodies come into contact with B antigens. If the blood groups are mixed then the results can be life threatening as we saw earlier with the French patient who died in 1668. This is because they did not know about the different blood groups, with the "ABO groups only discovered in 1901/1902 by Karl Landsteiner" (NHS Blood and Transplant: Blood Groups Leaflet) and the Rhesus groups discovered in 1937. Below is a bar chart of the percentages of each blood group present in the UK population with the most common being A+ and O+ and the rarest being AB-.

But what are the uses for each of the groups. Because of O- not having any antigens on its red blood cells it is known as the 'universal donor' as it can be given to anyone. This is because it cannot be targeted by any antibodies in the 'foreign' blood. At the other end: AB+ is the 'universal recipient' as a person with this blood group can receive any blood type due to having no anti-A or anti-B antibodies . However AB cannot be donated to people with either A or B blood types due to having both of these antigens on the surface of its red blood cells. Below is a table illustrating who can and can't receive each blood type. See if you can use the information provided above (about the antibodies and antigens with each blood group) to give reasons for why the recipient cannot receive certain blood groups.

How do you become a certain blood type? "ABO blood types are inherited through genes on chromosome 9 and they do not change as a result of environmental influences during life" ( "A and B are co-dominant alleles over O thus if a genotype of one parent is AO then its genotype is A" (as above). The table below shows the possible outcomes:

Parent Alleles
graphic arow pointing to the possible parental alleles for the ABO blood system along the top row and the left column

Although in some cases it does not work like this and is known as the Bombay phenotype ( 

Monday, 25 February 2013

90-seconds of exercise (HIIT)

The WEEK reported (a few weeks ago) an article on the "90-second exercise routine". As with The WEEK it pulls on all the different British newspapers for its stories, I couldn't find the exact story which it had drawn upon or even find, by searching through PubMed, the original study or even the abstract but I did find a similar article from MNT (Medical News Today) (albeit slightly outdated and which may represent ideas which have since been investigated further and maybe even improved on/discarded so please take the dates of these articles into account when reading them)(

The WEEK (Issue 902) (loosely taken from the Daily Mail)
"Scientists from the universities of Bath, Nottingham and Birmingham say that having warmed up for two minutes, people should engage in three, 30-second bursts of really intense exercise with 60-second rest periods in between. Results from an ongoing study involving hundreds of middle-aged people indicates that HIIT (High Intensity Interval Training) is just as effective as long sessions in the gym. The team isn't sure why this should be so, but notes that one advantage of HIIT is that it seems to suppress appetite; by contrast, longer workouts tend to leave people hungry."

However although this form of exercise known as HIIT sounds easily carried out, it has to be done properly for it to be effective. The 30-second bursts of high intensity workout should be something like "running up a flight of stairs or pedalling furiously on an exercise bike" (The WEEK (as above)) at almost maximum intensity.

For example "recent [be aware this report is from the 6th of March 2012] HIT research shows, that doing ten one-minute sprints on a stationary exercise bike with about one minute of rest in between, three times a week, is as good for improving muscle as many hours of less strenuous conventional long-term biking" (

In a study a few years ago (by Gibala around 2010) "participants had to pedal at their maximum possible effort level on a specially adapted lab bike. The thinking then was that 'all out' was an important part of the HIT [High Interval Training (referring to the same style of training as HIIT)] method.

But then, in 2010, Gibala and colleagues published
another study
in The Journal of Physiology, where they showed how a less extreme form of HIT worked just as well for people whose doctors might be a bit worried about them adopting the 'all out' method, for instance those who might be older, less fit and overweight.

In that form of HIT, the workout was still beyond the comfort zone of most people (about 95% of maximal
heart rate), but was only half of what might be regarded as an 'all out' sprint" (

The BBC ran a Horizon episode on HIIT with someone (known as Mosley) doing a HIIT programme for 4 weeks to observe the health effects. His programme ran like this (from
1.    First, you warm up for a couple of minutes with some gentle cycling: then you cycle as fast as you possibly can for 20 seconds.
2.    Cycle gently again for a couple of minutes while you catch your breath, then do another 20 seconds 'flat out'.
3.    Then, for a final time, two minutes gentle cycling to catch your breath, followed the third period of 20 seconds at 'full throttle'.
One of the health effects that the HIIT/HIT had on Mosley was on his insulin sensitivity...
"The researcher (Timmons) had tested Mosley for a number of health indices before he started, and then, after his 4 weeks of HIT, Mosley went back to the lab to be re-tested. A main test was for insulin sensitivity. When they measured Mosley's insulin sensitivity before he started his HIT exercise regime, the result showed he was just inside what would be regarded as healthy tolerance. Timmons told Mosley that research from a number of centers shows that doing 3 minutes HIT a week can improve insulin sensitivity by 24%. And this is exactly the amount by which Mosley's own index improved.

But bigger improvements than this have also been recorded, albeit with a slightly different HIT regime. A 2011 study by Gibala's group at McMaster published in Medicine & Science in Sports & Exercise found a 35% improvement in insulin sensitivity after only two weeks.

Insulin sensitivity is important for keeping blood sugar/glucose stable. It is not clear how HIT affects insulin sensitivity, but Timmons, and some other scientists that Mosley spoke to, suggest it could be because HIT uses many more muscles than conventional aerobic training. HIT engages 80% of the muscles of the body, compared to up to 40% during moderate jogging or cycling. HIT engages not only leg muscles, but also the muscles in the upper body, such as the arms and shoulders.

One of the effects of exercise is to break down glycogen in muscles. Glycogen is a stored form of glucose. The theory is that removing stores of glycogen makes way for fresh glucose to be deposited from the bloodstream. So the more muscle tissue that come under this influence, the more space that is available for new glucose deposits.

However there are some things that HIT will not necessarily do for you. For example, in Mosley's case, it didn't improve his aerobic fitness, the other main health index that Timmons and colleagues tested.

The evidence that ties aerobic fitness to health shows that one of the best predictors of a healthy long life is the body's ability to take in and use oxygen while we are exercising maximally. The more blood the heart pumps around the body, the more oxygen our muscles use and the lower our risk of disease and early death.

This idea stresses the idea that the more you do, does not necessarily mean the more you benefit.

What we are learning is that the link between exercise and health is an individual thing. Methods like HIT are useful, because very quickly, without spending a lot of time and effort, you can find out what works for you, and what doesn't, and fine-tune a program that you can fit more easily into your lifestyle." (

Wednesday, 16 January 2013


Onto one of the biggest media stories that was reported on around Christmas time. Norovirus or the 'winter vomiting bug' was responsible for a large number of dramatic media headlines over the winter period with a BBC headline entitled "winter vomiting cases at 1.1 million", described by some as an outbreak, others as a superbug...but really? I for one don't know anyone who contracted norovirus this year yet the stats presented by the media corporations are very dramatic as if no-one is untouched by it?

The Health Protection Agency (HPA) ( has up to date information on the number of laboratory cases reported of norovirus in England and Wales in each year from the year 2000 up to 2012 (but the 2012 data is at the moment provisional).

Laboratory reports of norovirus in England and Wales 2000-2012
This graph, from the HPA website, shows the number of laboratory reports in each year (for precise figures see the URL above). Between 2000 and 2005 the levels fluctuated but rose steadily from 2005 to 2009 and then steeply in 2010. Since 2010 there have been large fluctuations in the number of reports and it will be interesting to see the levels in 2013.
In 2010 there was also a media storm about norovirus, once again being described as a pandemic and a superbug (this would presumably be down to the increase that can be observed in the graph above). The big issue in 2011 was to do with "norovirus being found in 76% of British oysters" (

Information at tells you all you need to know about norovirus but I will pick out the useful parts;

"Noroviruses (NVs) are a genus of the Caliciviridae family of viruses found in 'used' water. They are concentrated in shellfish, oysters and plankton."

"The numbers [of cases] seem to have risen since about 1993 and this may in part be spurious due to the introduction of a commercially available enzyme-linked immunosorbent assay (ELISA) test that made diagnosis much easier. However, it may also be due to the emergence of a new strain of NV which is even more virulent [infectious] than the original strain."

"Outbreaks tend to affect no more than about 50% within a community. Outbreaks tend to be within November to April when pressures on hospitals are at their greatest." This therefore indicates an issue with infection control within hospitals when there is great pressure/the capacities are high; such as the use of alcohol gels and the ability to isolate those with the virus.
"There is a risk of mortality especially in the frail, immunocompromised [where the immune system is unable to respond effectively] and at the extremes of age."

A headline reading "winter vomiting cases at 1.1 million" is definitely an alarming headline to read. But as we can see from the data in the above graph and the detailed values on the HPA website their cases are nowhere near the 1 million mark (only just reaching 10,000).

The 1.1 million value has therefore been quoted on the basis that "for each confirmed case, there are a further 288 unreported cases, as the vast majority of those affected do not seek healthcare services in response to their illness" ( So based on the current 4,407 number of laboratory cases reported (as of yesterday rather than the BBC's report on the 2 January) the total number of cases is at 1,273,623 across England and Wales. So maybe the ground shaking figures on the BBC news website are relevant but still may not be completely accurate as 288 is only a rough guide to the levels of undiagnosed norovirus.

"John Harris, an expert in norovirus from the HPA said: “Norovirus activity always varies from year to year and although we might have expected cases to rise again now we have passed the New Year period this hasn’t been the case. We can’t read anything into this fall and don’t know how busy the rest of the season will be. The busiest months are normally from December to April, so further cases will occur but we can’t say if there will be further significant increases in the number of laboratory reports.

“There have been reports in the media of people with symptoms of norovirus attending their local hospital but we would urge people not to do this. If you think you may have the illness then it is important to stay away from any healthcare facility and care homes to avoid spreading it to people who may have underlying health conditions and already be vulnerable” (

But there is no need to worry, not as the NHS was  provided with "additional funding to help it cope with the added pressure that the winter brought" but also the statement from the Department of Health in England who "said 2.4% of beds were closed in the NHS due to norovirus symptoms compared with a peak of 2.9% last year." (

Maybe we should just follow Charlie Brooker in his suggestion?
"If things go disastrously wrong, and you've shaken someone's revolting disease-sodden hand and you don't have immediate access to hot water and a sink, it's imperative to remember your hand is "evil" until you've had a chance to wash it. Don't eat with it, and don't pick your nose or rub your eye with it either or you will die. Keep it in a pocket. Or sit on it... Just don't use it. Now wash your hands." (

Start to 2013

As it's recently been New Year and Christmas (and I haven't posted for a while!) I thought I'd do a story based on alcohol, and whilst we are having a post about alcohol, why not tie in smoking too.

The BBC reported on January 2nd that "alcohol calories 'too often ignored'"...."people watching their weight should pay closer attention to how much alcohol they drink since it is second only to fat in terms of calorie content [reported by World Cancer Research Fund (WCRF)]. Eating or drinking too many calories on a regular basis can lead to weight gain. Unlike food, alcoholic drinks have very little or no nutritional value" (

An interesting calorie calculator was embedded in the report ( showing the number of calories consumed with certain drinks, how many chocolate digestive biscuits that equated to and then how many minutes of brisk walking it would take to walk off that number of calories. As an example 2 standard glasses of wine equates to 3 chocolate biscuits in terms of calorie content and 52 minutes of brisk walking to burn those 248 calories off.

I also found an abstract for a study entitled "Alcohol consumption, nutrient intake and relative body weight among US adults" at ( The study showed that  "drinkers had significantly higher intakes of total calories than non-drinkers, but only because of their intakes of alcoholic calories. Among drinkers, the intakes of non-alcoholic calories decreased as alcohol intakes increased, and it was estimated that between 15 and 41% of the alcoholic calories replaced non-alcoholic calories. Despite their higher caloric intakes, drinkers were not more obese than non-drinkers." It was therefore "suggested that alcoholic calories may be less efficiently utilized than non-alcoholic calories, or may interfere with utilization of non-alcoholic calories."

The smoking story was about research (carried out by the universities of Oxford, Cambridge and Kings College London) that challenged the "widely held belief that giving up smoking makes you more edgy and that smoking [itself] relieves stress". The story was run on the BBC, Medical News Today and also in The WEEK (Issue 902). On the Medical News Today website ( the following quote from researchers on the project was used. The researchers wrote:
"The belief that smoking is stress relieving is pervasive, but almost certainly wrong. The reverse is true: smoking is probably anxiogenic (causes anxiety) and smokers deserve to know this and understand how their own experience may be misleading."
"The researchers recruited 491 smokers who attended NHS smoking clinics, and tested their anxiety levels...when their anxiety levels were tested again, the quitters were found to have reduced their anxiety by nine points on average, whereas those who had failed to quit were feeling more anxious: their levels had increased three points" (The WEEK).
"The decrease in anxiety was particularly noticeable among the ex-smokers who used to smoke "to cope", compared to those who used to smoke "for pleasure" (Medical News Today article: above).
The researchers concluded saying "stopping smoking probably reduces anxiety and the effect is probably larger in those who have a psychiatric disorder and who smoke to cope with stress" (MNT article).