No door? No problem. T. cruzi uses the window to cause Chagas Disease

For invasive pathogens the only way to survive, and consequently make you sick, is to get inside your cells. This is a rough exercise as you have an immune system working everywhere in the body to prevent this and the cell to be invaded is none too happy with the idea either so invasive pathogens must use tricks.

After evading or surviving the immune system, another post for another day, some exploit a mechanism called receptor mediated endocytosis (RME), in which the pathogen binds to a receptor on the cell triggering the cell to alter its shape to internalise the pathogen. RME is used by cells to recycle extracellular components but it a pathogen can make itself fit the receptor instead it can trick the cell into giving it free access to its insides.

Another mechanism, commonly employed by membrane bound viruses, is membrane fusion. Given that membrane bound viruses contain a secondary structure called the nucleocapsid, which houses the genome, they can fuse their own membranes with the host cell which results in the nucleocapsid's release into the cytoplasm.

(a) HIV entry by fusion and (b) receptor mediated endocytosis of light blue dots ((a) modified from credit and (b) modified from credit

Treating the Bends

Last week I wrote about the Bends, a medical problem based in an understanding of physics that results in bubbles of (primarily) nitrogen in your blood if you move from one atmospheric pressure to another to quickly, typically surfacing from depth while diving too fast.

Of course I meant to point out that decompression occurs when the external atmospheric pressure drops quickly. Most commonly this occurs in divers but also happens in astronauts. I’d never really thought about that before.

Anyway I got as far as explaining how it occurs last time. This time we are interested in how you fix it.

Physics + Medicine = The Bends

About a fortnight ago I was in the unusual position of teaching human biology to medical physicists and physics to medical students. Interestingly, during this overlapping week a disease came up in both tutes, a physics based medical condition.

Mucous Cancer - The mess of Pseudomyxoma peritonei

This post is very important to me for two reasons. First of it’s my very first proper post at my new home here at Disease Prone. Secondly it is a post I have been in the process of putting together for a while after it was suggested to me by my lovely wife, a nurse whose insights in to disease and treatment I hope to include as regularly as possible. I hope you enjoy it and all future posts as much as I enjoy writing them. Peace out.

The last time I wrote about cancer it was for the Scientific American regarding how bacteria can be used as treatments so really it wasn’t even cancer I was talking about but when I was told about this doosey of a cancer I couldn’t help but write about it. This is significant for me as I am a bacteriologist who has spent a long time trying to avoid cancer (developing or writing about it), too many signalling pathways (imagine trying to memorise dozens of images like this), ick.