Your blood and what you can do with it.

It flows through all of our veins, and although it looks identical from person to person, there is a lot more than meets the eye with blood. Firstly, a common misconception is that blood is just a red liquid that flows through our veins and arteries when in actual fact it is much more complex. Blood is a series of cells suspended in plasma:

• Erythrocytes – the biconcaved red blood cells are the most abundant and are the principal means of delivering oxygen to body tissues via the circulatory system.
• Leukocytes – these white blood cells are the immune effectors. There are several types of white blood cells with a range of specific and general immune functions.
• Platelets – important for coagulation. At a site of interruption, platelets prevent bleeding by clotting (thus the formation of scabs).

The constituents of blood.

Most of us have heard the term “blood type” especially if you are generous enough to donate your blood, but many people do not understand the key differences between the blood types and why certain people cannot receive specific blood types based on the composition of their erythrocytes (red blood cells). Also did you know that there are currently 33 recognised human blood group systems? However it is commonly divided into 4 main groups: A, B, AB and O (known as the ABO system), and these 4 groups can either be RhD positive or RhD negative.

The ABO system is determined by the presence of specific glycoproteins on the surface of the red blood cells known as antigens. Antigens are unique, microscopic markers that need to be matched correctly otherwise complications can arise during blood transfusions. Differentiation is relatively simple, if the red blood cells are covered in A antigens then that person is blood type A. If they are covered in B antigens then they are type B. Both A and B antigens type AB and if they have neither then they will be categorised as O. The significance of matching blood groups in transfusion is a result of antibodies associated with blood types. For instance, blood type A has antibodies against B antigens (and vice versa) meaning they are recognised as foreign to the body disposed of immunologically. Type O blood has antibodies against A and B antigens whilst AB blood has no antibodies at all. This seems fairly complicated with lots of letters being thrown around so I will do my best to simplify it.

• Blood Type O – has no antigens so can be universally donated as no antibodies can recognise it as foreign. Unfortunately as it has antibodies against A and B, people with type O blood can receive blood from the O group only. (Universal donor)
• Blood Type AB – Has no antibodies so can receive blood from any other blood group. (Universal recipient)
• Blood Type A – Can receive blood from type A and O but will reject type B and AB due to antibodies against B antigens.
• Blood Type B – Can receive blood from type B and O but not A or AB due to antibodies against A.

Simple representation of the surface antigenic make up of red blood cells.

To make matters slightly more complicated blood types also fall under the Rh system. This is based on 5 Rhesus antigens: C, c, D, E and e. Most important is the D antigen whereby the presence of which makes a blood type positive and absence negative. The presence of the D antigen can also cause a transfusion reaction so the true universal donor blood type is O- as it has no A, B or Rh antigens for a recipient to reject.

So there you have it,  a brief overview of what is going on in your veins. It is all well and good to understand what your blood type is but it is much more important to do something with it. The volume of blood in an adult human is approximately 5 litres. When donating blood a mere 470mls are taken and that is regenerated pretty rapidly (fluid in less than 24 hours, red blood cells in 3 weeks and iron in around 8 weeks). For those of you that haven’t donated blood before I urge you to do so. The nurses are always accommodating to those who are nervous with needles and it is far from painful. About half as sore as a wasp sting when the needle enters then no pain during the process. Some people experience slight dizziness and or light-headedness but the free tea, coffee and biscuits quickly squares you up. Donating blood is such a simple act that benefits so many people in cases of transfusions, serious accidents, cancers, childbirth, bone marrow failure and surgeries to name a few.

In closing I urge you to do something incredible. Give blood. Look for your local donation times and dates here:

https://www.scotblood.co.uk/

Smoking tobacco and a look at e-cigarettes

I am not just a non-smoker. I am an anti-smoker. Not only because of the catastrophic health defects but I just hate the smell. Cigarettes are a known cause of lung, mouth, lip, throat, larynx, oesophagus, bladder, kidney, liver, stomach and pancreatic cancer to name a few. Damaged caused to the heart also places a smoker at risk to heart disease and other vascular problems. It begs the question, how can simply smoking cause so many problems?

Well, tobacco smoke is rich with compounds emitted in gases and condensed tar particles. Most of these compounds are genotoxic (genetically harmful) and carcinogenic (cancer causing). The constituents of the compounds are alkenes, nitrosamines, aromatic and heterocyclic hydrocarbons and amines (generally synthetic and very harmful). Issues are slightly less severe as second hand smoke but are still heavily detrimental.

The effects of second hand smoke on infants as well as adults.

Adverse effects of smoking tobacco (there are more!)

The latest smoking trend however is e-cigarettes. I for one have welcomed it based entirely on olfactory reasons but are they really a clean and “healthy” alternative to the classic smoke and tar combo? Until recently, electronic cigarettes have had very little laboratory testing and as a result they have been marketed as tobacco-free, nicotine delivery devices that are a safer, more sociable option opposed to cigarettes. On a social front, studies have shown promise that e-cigarettes may be a useful tool in smoking abstinence. Respondents to a survey published in the American Journal of Preventive Medicine found that using e-cigarettes for a prolonged period of time increased rate of smoking cessation. The relevance of this study is questionable as tobacco consumption is self-monitored and sample sizes limited. On the contrary to smoking cessation, e-cigarettes have been found to have a “glamour factor”. In a study published this year, it has been found that passive exposure to e-cigarettes significantly increases observers’ desire or urge to smoke a regular cigarette or to try an e-cigarette for the first time. The funky flavours and sleek designs make them cooler than the average white stick and tar taste with the added bonus of “smoking” indoors.

Attractive designs such as this could be encouraging more people to start smoking than help them to stop.

Now for the science. E-cigarettes still contain nicotine, a parasymphathomimetic alkaloid. This is not only worth 54 points on scrabble (without any bonus squares), but it is a naturally occurring insecticide in plants, ie. Toxic. In humans, it acts on the α3β4 ganglion type nicotinic receptor in the adrenal ganglia/medulla as well as a central nervous system α4β2 nicotinic causing an increase in dopamine and epinephrine contributing the relaxation or happiness associated with inhalation. As it increases cholinergic (neuron receptor proteins) and adrenergic signalling, this impedes apoptosis (programmed cell death) which is essential for preventing the onset of tumours. Nicotine also stimulates angiogenesis and neovascularisation. The be all and end all is that nicotine itself can cause cancer and a result, so can e-cigarettes. On the plus side they do not possess the fatal ailments directly associated from tobacco smoking and levels of nicotine can be altered by purchasing varying strengths of cigarette liquid.

I hope that these messages are slightly clearer than the SMOKING KILLS note that is now compulsory for all smoking products, although in my opinion if the product you are consuming directly tells you it will kill you it’s a pretty clear sign to avoid it.