It is a well known fact that the human heart uses electrical currents in order to keep the cardiac muscles pumping in time. The current it taken to the muscle cells by conducting cells which pass the current through the heart to the correct places. The sinoatrial node is the originator of the signal which then moves to activate the atria and then the ventricles.
Now I actually have been diagnosed with having first degree heart block, which is so minor it doesn’t even cause noticeable bradycardia (slowing of heart beat). This means that the due to a lack of conductivity in my heart there is a slight delay between the contraction of the atria and the ventricles although not enough to have any noticeable adverse effects. For others though, it can be a lot more serious. Cardiovascular diseased cause the highest number of deaths in the world according to the World Health Organisation (WHO?), with many of these being caused by arrhythmias.
When people have myocardial infarctions (heart attacks) the cardiomyocytes (heart muscle cells) can suffer hypoxia (lack of oxygen) and so apoptosis (the death of cells) can occur. The (very complicatedly named) effects can be mitigated through a process called angiogenesis. This is where new blood vessels are created rapidly in order to perforate some living tissue and in this case combat the hypoxia. Now when it comes to treating and intervening in patients with growing areas of dead cells (the infarct) in the heart, fitting a catheter is the most reliable cure. Cell based therapies or those that angiogenic assistance could be used to treat the growing risk of a heart attack but no clinical trials have proven them to be a success. It can be seen as worrying that in the last fifty years (the nobel prize for cardiac catheters was awarded in 1956) there have been no more advancements or great innovations.
Most readers will probably be aware of how important stem cells are when it comes to medical research. As they have yet to differentiate they have the possibility of becoming any cell in the body if required, but this great variability comes with an inherent instability. The hematopoietic stem cells in the bone marrow, the cells from which the blood cells can be formed, have the potential to produce leukaemia and other blood cancers. There is also the risk of local tumours spreading their cells into the bone marrow which can result in cancer stem cells and rapid bone metastasis as the skeleton is invaded by the cancer. It is important to understand how the standard and malevolent stem cells interact with each other in the bone marrow so that these conditions can be counteracted and prevented.
A few months ago I wrote this post about using two photon fluorescence to study the capillary system. The basic idea being to use infrared light, which passes through flesh easily, to excite the fluorescent dye but to use the process of two photon absorption so that the remitted photon can be of greater frequency than infrared. Now although this can be done with a chemical dye, there is another option.
When people talk about organs the instant thoughts probably go to the heart, liver, stomach and kidneys. The liver is the largest of these internal organs but when it comes to largest organ overall it us outstripped by the skin which is often not thought of as an organ but does contribute to about 15% of a human’s body weight. The skin is, like almost everything else in the human body, made of a lot of water. 64% of the skin is in fact made of water.
Positron emission tomography (PET) is the process of injecting a radioactive dye into a human’s so that when it decays positrons (positive electrons) are emitted which can be used to learn about what might have gone wrong in the body. Often the dye is in fact glucose with the radioactive component attached so it will easily be absorbed into the blood and transferred around the body to the locations of interest. One of the other options is to use a metal ion as many of these are also required by the body and so accepted willingly. This study is looking primarily at copper (Cu) and the possibility of using it as the radioactive dye.
The blood brain barrier is an extremely selective semipermeable mmembrane which separates the blood that circulates in the body from the fluids that exist in the brain. Despite being excellent at preventing various neurotoxins and blood based diseases from infiltrating the brain, it manages to become a hindrance when it comes to administering drugs which want to directly effect the brain. This is one of the reasons that central nervous system diseases are so difficult to cure. One of the methods that has been employed for over fifteen years is to administer focused ultrasound which can work with induced microbubbles circulating in the body to increase the permeability of the blood brain barrier.