I'd like to tell you a curious story. Jane was a 52 year old woman in need of a kidney transplant. Thankfully she had three loving sons who were all very happy to give her one of theirs. So Jane's doctors performed tests to find out which of the three boys would be the best match, but the results surprised everyone. In the words of Jeremy Kyle, the DNA test showed that Jane was not the mother of two of the boys... Hang on, said Jane, child birth is not something you easily forget. They're definitely mine. And she was right. It turns out Jane was a chimera. Chimerism is the existence of two genetically different cell lines in one organism. This can arise for a number of reasons- it can be iatrogenic, like when someone has an organ transplant, or it can be naturally occurring. In Jane's case, it began in her mum's womb, with two eggs that had been fertilised by different sperm creating two embryos. Ordinarily, they would develop into two non-identical twins. However in Jane's case the two balls of cells fused early in development creating one person with both cell lines. Thus when doctors did the first tissue typing tests on Jane, just by chance they had only sampled the 'yellow' cell line which was responsible for one of her sons. When they went back again they found the 'pink' cell line which had given rise to the other two boys. This particular type of human chimerism is thought to be pretty rare- there are only 30 case reports in the literature. (Though remarkably both House and CSI's Gil Grissom have encountered cases.) What happens far more frequently is fetal microchimerism- which occurs in pregnant women when cells cross the placenta from baby to mum. This is awesome because we used to think the placenta was this barrier which prevented any cells crossing over. Now we've found both cells and free floating DNA cross the placenta, and that the cells can hang around for decades after the baby was born. Why? As is often the case in medicine we're not sure but one theory is that the fetal cells might have healing properties for mum. In pregnant mice who've had a heart attack, fetal cells can travel to the mum's heart where the develop into new heart muscle to repair the damage. Whilst we're still in the early stages of understanding why this happens, we already have a practical application. In the United States today, a pregnant woman can have a blood test which isn't looking for abnormalities in her DNA but in that of her fetus. The DNA test isn't conclusive enough to be used to diagnose genetic conditions, but it is a good screening test for certain trisomies including Down's syndrome. Now, we started with a curious tale, so lets close with a curious fact, and one that's appropriate for Mother's Day: This exchange of cells across the placenta is a two way process. So you may well have some of your mum's cells rushing through your veins right now. In my case they're probably the ones that tell me to put on sensible shoes and put that boy down... (FYI: This is a story I originally posted on my own blog)
Dr Catherine Carver
about 7 years ago
15 Cardiology Quick Facts and Mnemonics for Health Professionals. Quick way to learn and remember important cardiology facts. Perfect for all health sciences...
over 4 years ago
In this discussion-based podcast we discuss the aetiology and manifestations of ischaemic heart disease. Specifically, we discuss: * The process of atherosclerosis * Atherosclerotic risk factors * Clinical manifestations - stable angina and the acute coronary syndrome.
over 10 years ago
This is one of a series of podcasts which I made with bus journey's in mind. They last no longer than 12minutes and deal with 'traditionally difficult' topics in a 'bite-sized' manner suitable for revision. They are short, sweet and designed to help the busy medical student save time and fit their revision in around their crazy lifestyles! They are animated powerpoint slides with an audio voice over.
Charlotte Alisa Clifford
about 9 years ago
This animation shows a simplified version of the macrophage's role in the initiation of atherosclerosis. In an atherosclerotic-prone blood vessel, macrophages invade the subendothelial space. Oxidised Low-Density Lipoproteins (oxLDL) present within the vessel wall will bind to scavenger receptors on the macrophage's surface, such as CD36. This will activate the macrophage, and it will phagocytose the oxLDL. As this process continues, the macrophage increases in size and forms a Foam Cell, which is too large to pass between the endothelial cells back into the lumen. Therefore, the foam cells remain in the subendothelial space and are the main cells present within an atherosclerotic plaque. *** Done for Student Selected Component (SSC), University of Aberdeen. Year 2. 2011. Made in Adobe Photoshop CS2 and Adobe Imageready.
about 9 years ago
Your heart is a pump that is responsible for delivering blood to all parts of your body. Arteries carry oxygen-rich blood from the lungs to nourish the cells, and veins transport oxygen-poor blood on its way back to the heart and lungs.
almost 4 years ago
The ability to carry out a thorough and slick diabetic foot examination is something every medic needs to master. This video aims to give you an idea of what's required in the OSCE and you can then customise the examination to suit your own personal style. Make sure to head over to http://geekymedics.com/2010/10/10/diabetic-foot-examination/ to see the written guide alongside the video. Like us on Facebook http://www.facebook.com/geekymedics Follow us on Twitter at http://www.twitter.com/geekymedics You should always adhere to your medical schools / local hospital trusts guidelines when performing examinations or clinical procedures.
over 6 years ago
The heart's conductions system controls the generation and propagation of electric signals or action potentials causing the hearts muscles to contract and the heart to pump blood.
over 6 years ago
The VeinViewer uses near-infrared light to detect vessels and blood up to 10mm beneath the surface, and projects a picture onto the skin to reveal vessel structure and blood flow in real time.
about 6 years ago