Feb 28 - Antifungals and Mycology

Question 1

How do Amantidine and Rimantidine fxn?

Answer 1

They block uncoating by M2 protein, a membrane protein, through a viral proton channel

Question 2

How do Zanamivir and Oseltamivir fxn?

Answer 2

They inhibit neuramidase

Question 3

What do Amantidine and Rimantidine treat?

Answer 3

Influenza, Type A

Question 4

What do Zanamivir and Oseltamivir treat?

Answer 4

Influenza, Type A and B

Question 5

What drug(s) would you give to a pregnant woman with the flu?

Answer 5

Zanamivir or Oseltamivir

Question 6

How is Rimantidine eliminated?

Answer 6

Hepatic

Question 7

How is Amantidine eliminated?

Answer 7

Renally

Question 8

Generally, what would you use to treat HSV I, II, VZV, or CMV?

Answer 8

Acyclovir, Valacyclovir, Gancyclovir, or Docosanol

Question 9

How do Acyclovir, Valacyclovir, and Gancyclovir fxn?

Answer 9

They inhibit a virus-specific polymerase

Question 10

Which has good oral absorption, Acyclovir or Valacyclovir?

Answer 10

Valacyclovir

Question 11

What is necessary for (Val)Acyclovir to be converted to its active form?

Answer 11

A viral thymidine kinase (which also grants these drugs their selectivity)

Question 12

How does Docosanol fxn?

Answer 12

It disallows viral envelope coating - it is a long-chain saturated alcohol

Question 13

Abreva = (generic?)

Answer 13

Docosanol

Question 14

What is the biggest concern for a Pt with CMV?

Answer 14

Retinitis

Question 15

What do you give a Pt with active CMV?

Answer 15

Gancyclovir or Valgancyclovir

Question 16

What are the adverse effects of (Val)gancyclovir?

Answer 16

Nephrotoxicity, myelosuppression, hypocalcemia

Question 17

What drug could treat both HepC and RSV?

Answer 17

Ribiviron

Question 18

How does yeast classically present on histological slide?

Answer 18

Arranged in cell-to-cell chains with hypochromic cytoplasm

Question 19

Are fungi unicellular or multicellular? Sexual or asexual?

Answer 19

Yes. Yes to all the above

Question 20

What is fungal cell wall made of? Why do we care?

Answer 20

Chitin (very rigid), and provides a drug target with excellent selectivity

Question 21

What do fungi use instead of cholesterol? Why do we care?

Answer 21

Ergosterol - provides a drug target with excellent selectivity

Question 22

What are pseudohyphe?

Answer 22

Elongated, linked yeast forms that kind of look like worms of slides

Question 23

Tell me a little about yeast species

Answer 23

Unicellular balls, with fission/budding reproduction that are creamy/pasty in appearance - vary in size

Question 24

What are true hyphe?

Answer 24

Tubular, filament-like fungal structures with BRANCHING - not unicellular, but can be septate or aseptate.

Question 25

What are your dimorphic fungal species of note?

Answer 25

``` "Some Can Have Both Phases" Sporothrix Colcidioides Histoplasmosis Blastomyces Paracoccydiosis ```

Question 26

Define Pleomorphic:

Answer 26

The culture plate has several different growth types at the same time

Question 27

Define aerial hyphe

Answer 27

Hyphe that grow up and down

Question 28

Define vegetative hyphe

Answer 28

Hyphe that spread laterally on the surface of the medium

Question 29

Define rhizoids

Answer 29

Root-like structures on the bottom of the hyphe

Question 30

Define septate

Answer 30

cells in a hyphe-like chain that are divided by cell walls

Question 31

Define spore

Answer 31

The asexual form of reproduction - resistant to temp, pH, H2O change

Question 32

What is a conidiospore?

Answer 32

A pine-cone looking spore

Question 33

What is a microconidiae?

Answer 33

A spore that looks like a sparsely-branched tree

Question 34

What is a sporangiophore?

Answer 34

A structure that contains developing spores, looks like a tiny bag of fish-eyes

Question 35

What is a chlamydospore?

Answer 35

Hardy, resistant balls interspersed on hyphe that are made when the fungus is under environmental stress

Question 36

What is an arthrospore?

Answer 36

An asexual spore that develops on the hyphe - looks like lumpy string

Question 37

What is a spherule?

Answer 37

A large asexual spore, typically seen outside the body

Question 38

What is a blastoconidia?

Answer 38

A small bud on a single-celled yeast

Question 39

What is a thallus?

Answer 39

A cultured colony (can be wooly, smooth, cottony)

Question 40

When preparing a sample, what do you add to remove the human tissue but leave the fungal?

Answer 40

KOH

Question 41

What is the difference between Sabouraud's agar, Mycocol agar, and Dermatophyte test medium?

Answer 41

Sabouraud's agar = non selective Mycocol agar = some antiB Dermatophyte test medium = antiB + pH gradient

Question 42

How does Amphoterecin fxn?

Answer 42

"Polyenes punch holes!" FungiCIDAL drug that inhibits erosterol synthesis

Question 43

How does Imidazole/Fluconazole/Triazoles fxn?

Answer 43

They inhibit 1,4-dimethylase - inhibits general ergosterol synthesis. Fungistatic, will go into the CSF

Question 44

How do Allylamines/Benzylamine fxn?

Answer 44

They block squalene epoxidase, which blocks 1,4-dimethylase, which inhibits general ergosterol synthesis. FungiCIDAL

Question 45

How do Echinocandins fxn?

Answer 45

They inhibit 1,3-glucan synthase (good for Candidae/Aspergillis infection)

Question 46

How does Griseofulvan fxn?

Answer 46

Inhibits the MT/spindle complex - good for ringworm of the scalp (take with ice cream yum)

Question 47

How does Flucytosine fxn?

Answer 47

Blocks the addition of more bp's in DNA synthesis

Question 48

How does Ciclopirox olamine fxn?

Answer 48

It chelates metals needed for fungal development

Question 49

What is a common side effect from improper use of an asthma inhaler? What organism causes this?

Answer 49

Oral thrush - Candidae

Question 50

What are our two opportunistic fungi?

Answer 50

Candidae and Aspergillis

Question 51

Are deep fungal infections better or worse than superficial ones?

Answer 51

Deep fungal infections are super nasty

Question 52

How do Amphotericin B and Nystatin work? Route of admin?

Answer 52

They are polyene ergosterol inhibitors. Amphotericin B = IV Nystatin = topical

Question 53

What is an adverse rxn to Amphotericin B or Nystatin?

Answer 53

Red Man Syndrome: chills, fever, shaking, hypotension, anemia due to kidney EPO depression, BM depression

Question 54

What would you use Terbinafine for?

Answer 54

Keratin (finger/toenail) fungal infections

Question 55

What is the difference between worms and parasites?

Answer 55

Worms develop in humans, but do not replicate. Parasites can replicate in humans

Question 56

Some ways parasites evade host immune responses?

Answer 56

Encapsulation, Immunosuppression Intraluminal location

Question 57

Three stages of Schistomiasis?

Answer 57

1) Swimmer's Itch 2) Febrile response/HSM 3 wks later 3) Cirrhosis, Bladder cancer, chronic inflammation

Question 58

How to treat schistomiasis?

Answer 58

Praziquantel

Question 59

How do shistosomes spread around?

Answer 59

Their eggs are excreted in the urine (s. haematobium) and feces

Question 60

What cell does malaria infect first/most readily?

Answer 60

Hepatocytes

Question 61

What is the lethal species of plasmodium?

Answer 61

P. falciferum: RBC lysis leading to rapid acute anemia Makes "nobs" that cling to vasculature - brain death via hypoxia