5B - Antibiotics

Question 1

Dr. Joseph Lister

Answer 1

found that mould inhibited growth of bacteria
“discovered” antiseptic surgery by killing bacteria
“Listerine” named after him

Question 2

Listerine and other mouthwashes

Answer 2

Often contain up to 25% alcohol
Long term use of high alcohol mouthwashes increases risk of oral cancer
Does Listerine kill germs? Yes, but many more remain
Salt water rinse an effective alternative

Question 3

Sulfa Drugs: the 1st antibacterials

Answer 3

Benzene sulfonamides-not antibiotics, but did inhibit bacterial growth by disrupting folic acid synthesis
could be applied as powders to wounds in the field WWII.

Question 4

Antibiotic

Answer 4

a compound that kills bacteria (by destroying bacterial cell walls.

Question 5

Antibacterial agent

Answer 5

antimetabolite (starves the bacteria, often of folic acid), eg. sulfa drugs

Question 6

Discovery of penicillin(20th century’s most important one?

Answer 6

Fleming grew a pure mould culture: discovered it was Penicillium notatum
Later isolated the pure chemical “antibiotic”component, named it “penicillin”
But needed a good large scale source of the mould

Question 7

The Process of Penicillin

Answer 7

Start “cold stored” penicillium culture on agar plate
Transfer to “shake flasks” ,with food (Sugars) and nutrients (ammonium salts), aa’s needed for growth
Resulting suspension can be transferred to seed tanks for further growth
Transfer to larger fermentation tank (30,000 gallons)
After 3-5 days , isolation
Temp, pH, mixing essential, sterilized air pumped in.

Question 8

Penicillins

Answer 8

ear/skin/respiratory/digestive/urinary infections, syphilis, scarlet fever

Question 9

Tetracyclines

Answer 9

respiratory/urinary infections, acne, bronchitis, whooping cough, typhus fever

Question 10

Cephalosporins

Answer 10

ear/throat/skin/urinary infections

Question 11

Chloramphenicol

Answer 11

typhoid fever, meningitis, eye/ear infections

Question 12

Erythromycins

Answer 12

skin/eye/respiratory/tissue infections, diphtheria.

Question 13

Spectinomycin

Answer 13

gonorrhea

Question 14

Gentamycin

Answer 14

bone/skin/lungs/abdomen infections

Question 15

New legislation re: farm animals

Answer 15

Antibiotics use would only be permisable to treat sick animals
At present, on many farms, low doses of antibiotics are included in the animal feed of healthy animals..results in weight gain

Question 16

Why no antimalarial drug?

Answer 16

Viewed as an African problem

No money in it for the Pharmaceutical industry

Question 17

Quinine

Answer 17

An alkaloid
Also antipyretic, analgesic, anti-inflammatory, anti-smallpox
British “colonial’ days-quinine was added to water in an attempt to prevent malaria

Question 18

Chloroquine

Answer 18

Used to prevent and treat malaria
BUT…many adverse side effects: itch, mood changes, blurred vision
Dangerous in overdose: doubling the normal dosage can be fatal
Malaria parasites now have developed widespread resistance to it

Question 19

Viruses

Answer 19

A virus contains a core of DNA or RNA(never both) wrapped in a protective shell(usually protein, maybe some carbos/lipids).
Viruses are parasites

Question 20

Fighting Viruses, #1 - Vaccines

Answer 20

A weakened strain of the virus is injected into the host so that antibodies can be produced against that specific virus(an ‘invading’ compound). These antibodies are then always ready to protect against future exposure to that particular virus(sometimes!).

Question 21

Fighting Viruses, #2 - Antiviral agents

Answer 21

General: stop DNA synthesis with modified nucleic acids For HIV*: inhibit production of the protein sheath (proteases, reverse transcriptase inhibitors) with non-nucleosidic compounds

Question 22

Immune Response - Antibody vs Antigen

Answer 22

An antibody* is a specific protein(immunoglobulin, -globulin) that is synthesized by white blood cells(B-lymphocytes) to eliminate/inactivate a pathogen that enters our body. These ‘invading’ compounds are usually disease-bearing bacteria or viruses. The ‘action’ occurs in the extracellular fluids, including the circulatory system. The invading material that causes antibody generation is termed an antigen

Question 23

Immune Response - the Down Side

Answer 23

The immune system cannot distinguish ‘good’ from ‘bad’ antigens. Hence organ transplants can be ‘rejected’ so that immuno-suppressants must be used with potentially dangerous consequences.
An overactive or misdirected immune system can attack its own tissue, eg.AUTOIMMUNE DISEASE

Question 24

Allergies - Immune Response Reversal

Answer 24

The body generates an antibody to some antigen. On subsequent exposure when the antibody/antigen reaction occurs, certain cells(especially in nose and bronchial system) are disrupted and release some potent chemicals of which the best known is histamine(from the amino acid, histidine). These particular antigens are called allergens.

Question 25

EpiPens

Answer 25

Carried by people with potentially fatal allergies : anaphylaxis: low blood pressure, reduced heart rate, swelling of lung tissue
Contain:epinephrine (adrenaline!)

Question 26

How does adrenaline stop anaphylaxis?

Answer 26

Acts on alpha and beta adrogenic receptors
Alpha receptors-in blood vessels, adrenaline is a vasoconstrictor and increases blood pressure
Beta receptors-in heart and lung tissue: heart beat is increased and airways open up

Question 27

Heart Pumping

Answer 27

In 24hrs the human heart pumps 8000L of blood and beats 100,000 times

Question 28

Vascular Blockage

Answer 28

For blood clots or thickness
Mild: platelet inhibitors(thinners), eg. aspirin Medium: anticoagulants/anticlotting, eg. heparin, warfarin(rat poison) Severe: thrombolytics(‘clot busters’ or ‘clot eating’ enzymes), eg. streptokinase, plasmin
For blockage by fatty plaque(artherosclerosis) divert/slow cholesterol production in liver with cholesterol-lowering drugs, eg. Lipitor (a ‘…statin’)

Question 29

Control heart beat

Answer 29

Too slow; use stimulants, eg. adrenaline, atropine, digoxin Too fast; use sedatives/tranquilizers Irregular(arrythmia); use smooth muscle relaxants, eg. lidocaine

Question 30

Cis-platin: mode of Action

Answer 30

Pt binds to N atom of guanine DNA base
Disrupts out of control (and normal) protein synthesis
Side effects: hair loss
Trans isomer is inactive

Question 31

Taxol (semi synthetic

Answer 31

Isolate from bark of pacific Yew tree, then modify it chemically
Acts by cutting off blood supply to tumor