E2L16: Chemical Methods - Non-Specific Chem. Combo (Denature Protein)

Question 1

What are the 2 ways to do non-specific chemical combinations (protein denaturing)?

Answer 1

1) oxidizing agents: removal H from enzyme functional groups in this case, but oxidation also happens w/ add’t of O2 (throwback to physical methods: heat)
2) alkylating agents: add’t organic group to functional enzyme group

–> attacks protein’s active group, e.g. formaldehyde to sulfhydryl group (SH)

Question 2

Halogens are oxidizing agents. Name some examples.

Answer 2

• iodine tincture
• iodophors
• chlorine (Cl2)
• sodium hypochlorite

Question 3

Talk about Halogens as a whole as oxidizing agents. MOA?

Answer 3

• intermediate effectiveness

- I + Cl, NOT Br

Question 4

Name all of the oxidizing agents!

Answer 4

• halogens: iodine tincture, iodophors, chlorine, sodium hypochlorite
• also hydrogen peroxide (H2O2)

Question 5

What are some advantages and disadvantages for halogens as oxidizing agents?

Answer 5

• adv: bactericidal, viricidal, fungicidal, amoebicidal, + slowly sporicidal (under best conditions); little better than alcohols
• dis: inactivated in organic matter (vomit/feces) + alkaline pH (basic), irritants (irritates tissues, slows healing), unstable (may evaporate–volatile), activity declines w/ drying, need free halogen for efficacy

Question 6

What’s an iodine tincture? What’s it made of? MOA?

Answer 6

• ex: of halogen - oxidizing agent
• 2% iodine tincture = I + ROH
• used as an antiseptic
• MOA: non-specific chem. combo –> protein oxidation

Question 7

What are Iodophors? What’s an example of an iodophor? MOA?

Answer 7

• ex: of halogen - oxidizing agent
• iodophor ex: betadine
• MOA: non-specific chem combo –> protein oxidation

Question 8

What are your 4 choices to disinfect catheters? Which is the best choice + why? How long must they all be on site?

Answer 8

• 4 choices: 2% chlorhexidine, iodine tincture, betadine, 70% alcohol
• ALL must be on site for 2 min before insertion
• BEST choice = 2% chlorhexidine b/c good residual action

Question 9

What is Betadine? What’s it used to test for + why? What’s the DOC for that condition?

Answer 9

• ex: of iodophor, halogen - oxidizing agent
• used to test for ophthalmia neonatorum b/c cheaper
• BUT, DOC is still erythromycin

Question 10

What is Chlorine (Cl2)? What must its residual concentration be, in order to be effective? Effective or naw?

Answer 10

• ex: halogen - oxidizing agent, toxic gas
• can be used for H2O purificaton
• added until residual concentration 0.5-1.0ppm, so that all bacteria inactivated
• effective, but limited use

Question 11

What is Sodium Hypochlorite? What’s a good concentration?

Answer 11

• ex: halogen - oxidizing agent
• 5.25% NaOCl in bleach
• MUST DILUTE before use
• 10% bleach basically 0.525% NaOCl

Question 12

Can you keep sodium hypochlorite for a long time? Why or why not?

Answer 12

NO, must be made fresh b/c doesn’t last long, Cl evaporates

Question 13

Sodium Hypochlorite

Answer 13

wtf

• “10% needles, IV drug users (against AIDS, Hep), inside of kidney dialysis machines on outside only need 1%”
• can also use H2O @ 80C for 30min –> no chem residue

Question 14

How much bleach would you need to disinfect a needle if you were to share needles?

Answer 14

10% bleach!!!

Question 15

What is Hydrogen Peroxide (H2O2)? Are there toxic residues left over? What % does it normally come in? At what % is it a sterilant? Is it safe as a sterilant? What sort of things is it typ. used for?

Answer 15

• ex: halogen - oxidizing agent
• no toxic residue left over
• normally 3% soln
• sterilant @ 10%, but too toxic on tissues (caustic)
• typ. used for inanimate, heat labile items (can’t be autoclave’d, ex: surgical implants, plastics)

Question 16

Why is Hydrogen Peroxide (H2O2) good for killing anaerobes such as Tetanus?

Answer 16

• our blood has CATALASE (breaks down H2O2) releasing O2, which kills tetanus (anaerobe)
• many microorg have catalase too + able to break down H2O2
• BUT, strep DOES NOT have catalase –> doesn’t break down H2O2 –> H2O2 kills strep!

Question 17

What is Necrotizing Fasciitis? What’s it also known as? What’s it caused by? What is an option for treatment?

Answer 17

• basically deprives tissues of O2
• “Flesh Eating Disease”
• Caused by Strep. pyogenes (et. al)
• can use H2O2 (even when H2O2 normally not used for deep wounds, but in this case, OK)

Question 18

What’s the MOA of alkylating agents? Name some examples. What are they as a whole?

Answer 18

• MOA: non-specific chem combo - inactivates enzyme functional groups
• ex: formaldehyde, gluteraldehyde, ethylene oxide
• they add an organic group (C+H) to enzyme’s functional group (ex: formaldehyde –> enzyme’s sulfhydryl group)

Question 19

What is formaldehyde? MOA? What does it come as? What’s it normally used for?

Answer 19

• actually a gas, alkylating agent
• adds to enzyme’s functional group to inactivate it
• comes in concentrated form as 37% Formalin
• used in embalming soln, sterilize vaccines (but need to remove before use b/c carcinogenic)

Question 20

Talk to me about Formalin. If you combine it with a tincture, will it sterilize or naw? Is it carcinogenic? What’s it used for?

Answer 20

• typ. 37% Formalin soln (normal form of formaldehyde)
• if make 8% soln of 37% Formalin + tincture (add alcohol) –> CAN STERILIZE!!!
• yes, carcinogenic –> need to clean well w/ H2O
• used for heat sensitive materials (cold sterilant b/c high sporocidal activity), like metal scalpels

Question 21

What’s Gluteraldehyde? Sporicidal/Sterilant or naw? How long would it take, if possible? What’s it used in?

Answer 21

• ex: alkylating agent
• 2% sporicidal/sterilant!!! STERILIZES!!!
• would take 3 hours to be sporicidal, but kills veggies w/in minutes
• used in dentist offices (equip), respiratory therapy equip, and cow teats (lmao)

Question 22

What’s Ethylene Oxide? Sterilant??? Carcinogenic? Explosive? What’s it used for? How’s it been used in the past?

Answer 22

• ex: alkylating agent, a gas
• COLD STERILANT! YES
• CARCINOGENIC! YES
• EXPLOSIVE??? YES!!!
• -> now OSHA regulated
• used for sterilizing heat sensitive things (ex: powders)
• in past, placed stuff in ethylene oxide filled bottles and would sterilize in 48 hours

Question 23

Which of these disinfectants acts by protein oxidation?

a) phenolics
b) aldehydes
c) halogens
d) alcohols
e) all of the above

Answer 23

c) halogens!!!

(phenols - protein coag, aldehydes - alkylating, alcohols - protein coag)!!! keep this in mind!!!

Question 24

Which of these is an alkylating agent?

a) halazone
b) hydrogen peroxide
c) betadine
d) bleach
e) ethylene oxide

Answer 24

e) ethylene oxide (n.b. one of the alkylating agents w/o “aldehyde” in name)

(halazone-wtf???, H2O2 - oxidizing, betadine - oxidizing, bleach - oxidizing)

Question 25

Which of the following pairs is not correctly matched?

a) AgNO3 - ophthalmia neonatorum
b) betadine - ophthalmia neonatorum
c) cresyl acetate - antiseptic + analgesic (pain relief)
d) 10% H2O2 - deep wounds
e) none of these

Answer 25

d) 10% H2O2 - deep wounds
(10% H2O2 is too toxic!!! H2O2 is no longer used for deep wounds nowadays, however, you can use H2O2 for Flesh Eating Disease)

Question 26

Which of the following substances can sterilize?

a) 70% ehtanol
b) sodium benzoate
c) 8% Formalin
d) sodium hypochlorite
e) betadine

Answer 26

c) 8% Formalin

I guess “tincture” would be implied w/ the 8%…

Question 27

Which of the following isn’t a heavy metal product?

a) argyrol
b) mercuric bichloride
c) thimerosal
d) bleach
e) zinc oxide

Answer 27

d) bleach (duh!)

Question 28

What is H2O2 considered to be? Disinfectant/sterilant?

Answer 28

Considered as ideal antiseptic disinfectant, b/c breaks down into O2 (bubbles) + H2O –> no toxic residue!