Medical Miracles, New Discoveries and BIG Babies!

My blog is based on the current and inspiring research of comparative physiologist, Dr. Suzy Munns. Being medical based research there may be some big words in here but I will do my best to explain them :) 

Lymphangiogenesis in geckos

A common treatment for breast cancer in women is to have a mastectomy. This involves removal of the whole breast and usually the removal of one or more lymph nodes from the armpit. Removal or blockage of the lymphatic system leads to swelling (oedema). Oedema can often occur after a mastectomy as lymphatic vessels are often removed to prevent the spread of cancer cells.

There are very few treatments for oedema and no cure. Humans have a very limited ability to regrow lymph vessels (lymphangiogenesis). Being a comparative physiologist, Dr. Munns decided to use geckos as a “Kroghian model” due to the fact that geckos regrow tails after autonomy. The interesting thing about geckos is that they regenerate all tissues in their tail; including muscle, nerve, cartilage, blood vessels and lymph vessels! She found that geckos regenerate a fully functioning lymphatic system in their tail within 3 weeks of dropping it.

The question is: Can her research team trigger lymphangiogenesis in humans with oedema???

Well the research on isolating the responsible proteins and genes continues, so you will have to stay tuned!

How do crocodilians breathe?

Reptiles like snakes and lizards, breathe by changing the volume of the body cavity. By contracting the costal muscles moving the ribs, the volume of the body cavity is increased, creating a negative pressure, which is restored to atmospheric level by air rushing into the lungs. Then, by contracting the body muscles, the volume of the body cavity is reduced, forcing air out of the lungs.

Crocodilians in the past have been known to use a diaphragmaticus muscle (dm) for lung ventilation (lu), in a process called the hepatic piston pump. This involves muscular movement of the pelvis (p) and liver (li) rather than the rib cage. However, this theory is currently in review after Dr. Munns and her other collaborators discovered that the hepatic piston pump is not the primary respiratory mechanism. Therefore, crocodilians are now suggested to use costal ventilation, like snakes and lizards, as the primary respiratory mechanism.

What is the purpose of the hepatic piston pump?

It is suggested that it could aid in the crocodiles buoyancy when posturing, diving and death rolls.

Pregnancy and lung compression in skinks

Viviparous reptiles like shingleback skinks and bluetongue skinks have multiple babies that take up a huge amount of space in the abdomen whilst developing. This is because their armoured bodies can’t expand like many mammals. Mothers’ lungs are significantly compressed during pregnancy, which can cause significant lung damage and decrease in ability to exchange gases. The photo on the left is a mother shingleback skink and her 3 newborn babies!!

The above figures show the lung capacity of a non-pregnant (left) and pregnant (right) shingleback skink.

Dr. Munns found that during the late stages of pregnancy, the skinks drastically increase their respiration rates. This behaviour is both energetically expensive and difficult for the skink to do because of the already compressed lungs. So, why would they breathe so quickly?? Preliminary findings suggest that the breathing is increased to clear the build-up of carbon dioxide produced by the foetuses, also to help the mother maintain a normal blood pH.

Another interesting thing that Dr. Munns found is that there is more blood flow to the top of the lungs where falveoli are the smallest and the blood flow is the highest. This creates a more efficient gas exchange, making it possible for these skinks to compress their lungs during pregnancy. Photo on the right shows a bluetongue skinks inflated lungs.

Photo credits go to Dr. Suzy Munns research lecture powerpoint slides and Google Images. Accessed on 8/12/14.