11 - Joseph Lister and Sterility (w/ Donald Hahn!)

11. Joseph Lister and Sterility (w/ Donald Hahn!)

To be a Nobel Laureate is one of the greatest honors that can be given. What does this prize represent? Where are the Prizes origins? Why are there fewer prizes in economics than other prizes? What are the complications with the Nobel Prize in today’s society? Was Alfred Nobel the last great Alfred? Let’s learn to be scientifically conversational.


General Learning Concepts

1)     What is sterility?

a.     Sterility and aseptic technique: Incapable of producing offspring; free from living germs or microorganisms. Aseptic technique is designed to provide a barrier between the microrganisms in the environment and some form of a sterile medium that one is working in.

i.     As simple as trying to avoid allowing fungus to grow in your bread or yogurt and spoil your food to as complicated as trying to prevent a virus from getting out of a biohazardous facility.

b.     What is a pathogen? A microorganism that can cause or will cause disease – also defined as a microbe that will cause damage in a host. This definition can be finicky depending on how some organisms may not experience disease or individuals in a microorganism population that are less capable of causing disease. [2]

c.     Why should we be sterile in scientific research or in medical fields? There are always variables that are inherent to everything.

i.     Say you’re at a friend’s place playing blackjack and you continuously keep losing. Your friend is a magician; you don’t know whether you’re losing because the cards aren’t in your favor or because you’re being tricked by sleight-of-hand. Remove the magician variable.

ii.     You move into a new apartment and want to know if the electricity is working. When you plug in a lamp, it doesn’t light up. Now you don’t know if the electricity doesn’t work, the lamp doesn’t work, or the lightbulb is burned out. You control for this by using other electronics that you know work.

iii.     I’m in lab, infecting cells with a virus. The cells die. What I don’t know is that the virus can’t kill the cells, but bacteria that is accidentally mixed in with the virus kills the cells. Now I’m at a loss for what has happened because I’ve failed to be sterile and controlled the variable of extra pathogens in my experiment.


2)     Joseph Lister and the development of sterility:

a.     Who was Joseph Lister? Commonly referred to as the father of modern surgery. Lister was born in Essex, England in 1827. His father was a Fellow of the Royal Society for study of red blood cells and creating lenses to view them. Lister became a surgeon by studying at the University College of the University of London. He was well known for his interested in inflammation, reaction of the immune system to foreign bodies.

b.     How did Joseph Lister contribute to sterility? The 1800’s were particularly unforgiving in terms of terms of surgery. Half of surgery patients died because of infection. It had been previously theorized that germs could cause disease but it wasn’t understood in terms of wounds and infection. Reading prior papers from Louis Pasteur gave Lister an idea that whatever caused fermentation (chemical breakdown by microorganisms) would also be involved in wound sepsis (life-threatening illness caused by your body's response to an infection). He recognized without skin to protect the wound, infection could come from the environment around him. He used carbolic acid (now known as phenol) to sterilize wounds.

c.     Who else has made significant contributions?

i.     Lawson Tait: Born in 1845 (Edinburgh, Scotland). Became a surgeon who became famous for being able to perform ovariectomies, a once 90% fatal operation. His success (asides from his prowess as a surgeon) was often related to believing in asepsis rather than antisepsis (a clean space instead of sterilizing to disinfect).

ii.     Ignaz Semmelweis: The “savior of mothers”. Born in 1818 in what is now Budapest, Hungary. Semmelweis proposed washing hands (in a chlorine solution with a low pH) could cut down on “childbed fever” (once with a mortality of 10 – 35%). Controlling infection between patients is critically important even today to reduce patient deaths and additional costs to patients and insurance providers.

iii.     Irony: Because germ theory was not well understood, these pioneers were unable to properly explain why their techniques saved lives. This caused friction in the medical community and often ousted these now famous physicians.


3)     What are commons methods of sterilizing things now?

a.     Heat (Incineration): Incineration is a process in which medical wastes burn and produce combustion gases and non-combustible residues (ashes). It is extremely effective at killing any microbiologically relevant pathogens (or living organisms in general).

b.     UV light: Ultraviolet (UV) light kills cells by damaging their DNA. Depending on the extent of DNA damage, the cell may die or be so “unfit” that it would not be able to survive. Essentially, two thymine’s would end up binding to each other, which should not happen.

c.     Chemicals: Phenol was a good example of a chemical that could kill bacteria; however, phenol is quite toxic to human tissue as well. We humans have oily skin that pathogens often use to stick to us. Luckily, soap molecules (detergents) work in a more mechanical way to essentially convince the oil particles (and thus their associated germs) to join up with water molecules so that they can be more readily washed away. However, with common hand washing techniques we tend to remove 40 – 60 % of germs from our hands with typical hand washing.

d.     Autoclave: Autoclave with steam, moisture, heat and pressure is used in order to inactivate the micro-organisms, and to sterilize the medical devices and for medical wastes treatment. Steam can be made hotter than the temperature that water boils (100 C) by increasing the pressure (think a big rice cooker). The water in the air allows for a more effective (better) transfer of heat than dry air.


4)     Questions for Mayor Hahn:

a.     What does it mean to be a Mayor of a borough that contains a R01 university as large as Penn State – University Park? How has appointing a student representative seat to the borough council changed relations between the borough and the university?

b.     Mayor Hahn has been educated as a lawyer: what is the importance of education or higher education? Is there an impact to ever increasing tuition?

c.     Research scientists are often met with failure. Mayor Hahn made a bid for state representative in 2000; how has persistence shaped your career both in and out of politics?


Calvin YeagerComment