Utmb Phd Final Exam

Front 1

Define reservoir of an infection.

Back 1

reservoir = site where microorganisms reproduce and maintain themselves for a long time.

all reservoirs are sources

Front 2

Define source of infection.

Back 2

source = site where microorganisms are temporarily deposited and little/no multiplication takes place

not all sources are reservoirs

Front 3

List portals of entry for infections.

Back 3

Mucous membranes: conjunctivae, respiratory tract, GI tract, genitourinary tract
Skin

Front 4

Most common nosocomial infection.

Back 4

urinary tract infection

Front 5

Highest mortality of nosocomial infections

Back 5

pneumonia

Front 6

In infection surveillance data for infection rates, what is the numerator and what is the denominator.

Back 6

Numerator = patients who developed the infection of interest

denominator = patient population at risk for this infection due to risk factors (devices, underlying diseases, medications, procedures, duration of stay)

Front 7

What is cumulative incidence?

Back 7

Cumulative incidence is the proportion of patients at risk for an infection who developed that infection at some point during a period of observation.

Front 8

What is the incidence rate for an infection?

Back 8

Incidence rate is the number of cases of infection per unit of time.

Front 9

What are the 3 basic principles needed for valid comparisons of nosocomial infection rates over time and between institutions?

Back 9

1. Uniform application of uniform definitions
2. Uniform density/intensity of surveillance (reporting is essential)
3. Adjustment of the denominator for severity of illness.

Front 10

3 classes of helminths

Back 10

cestodes, nematodes and trematodes

Front 11

Ascaris lumbricoides

Back 11

Nematode
Largest parasitic nematode
fecal-oral transmission
normally found in small intestines but may wander to bile duct or appendix
can obstruct blood flow

treatment: mebendazole and pyrantel pamoate

Front 12

Hookworm

Back 12

causes iron-deficiency anemia (they suck blood from intestine walls)

Front 13

Strongyloides stercoralis

Back 13

Acquired from skin contact with soil infected with filariform larva - migrate to the lungs and break through into alveoli - coughed up and swallowed and adults develop in intestine and produce eggs

Front 14

What is strongyloides stercoralis autoinfection?

Back 14

most eggs made by adults in the intestine pass through feces and go back to living in soil but some can become filariform and re-infect the host, called autoinfection
can develop into life threatening hyperinfection - massive autoinfection caused by immunosuppression (AIDS, corticosteriods) and can lead to death from enteric bacterial sepsis and respiratory failure from hemorrhage and pneumonia

Front 15

Enterobius vermicularis

Back 15

pinworm - most common helminth infection in US
life cycle only in humans
ingested eggs hatch in the small intestine, become adults and migrate to colon
females migrate to the perianal skin and release eggs (eggs not found in stools) --> perianal pruritis
diagnose with scotch tape test
treat with mebendazole or pyrantel pamoate

Front 16

trichuris trichiura

Back 16

often innocuous but can be associated with anemia and rectal prolapse

Front 17

Filiaria

Back 17

blood and tissue nematodes, cause lymphoid obstructions
often more active at night

Front 18

list the 4 types of malaria

Back 18

plasmodium falciparum - ~15%, highest mortality
plasmodium vivax - 80%
plasmodium ovale
plamsodium malariae

Front 19

What is the best stain for parasites?

Back 19

Geimsa

Front 20

What animal is the plasmodia vector and definitive host (sexual stage)?

Back 20

Anopheles mosquito

Front 21

Which two plasmodium types cause latent infection in the liver?

Back 21

vivax and ovale

Front 22

Why does p. falciparum cause more severe malaria?

Back 22

look for distinctive banana shape!

it can infect RBCs of any age - worse anemia

erythrocyte membrane protein 1 (PfEMP1) forms knobs on surfaces of RBCs and binds to ligands on endothelial cells (CD36, thrombospondin, VCAM1, ICAM1, E-selectin) resulting in seqestration and also RBCs clump together (rosetting) => thrombosis and ischemia due to poor perfusion can cause cerebral malaria

stimulated production of high levels of cytokines which increase fever, induce NO production and increase tissue damage and induce expression of endothelial receptors for PfEMP1 (exacerbates sequestration)

Front 23

Describe plasmodium life cycel as it relates to latent period, appearance of symptoms and febrile paroxysm.

Back 23

sporozoites injected by mosquito bite enter hepatocytes and begin replicating (latent period)

merozoites burst out of liver cells and infect RBCs (appearance of symptoms)

erythrocytic phase, plasmodium becomes ring-shaped trophozoite, them a schizont filled with merozoites, when they release the merozoites from the RBC you get the recurrent chills, fever, and sweat symptoms

Front 24

What is SERM?

drug

Back 24

selective estrogen receptor modulators

Front 25

What are the two types of aromatase inhibitors?

drug

Back 25

Type 1: steroidal - false substrate for aromatase that is converted to a reactive intermediate that binds to the enzyme and inactivates it

Type 2: non-steroidal - competetive aromatase inhibitors, bind to the heme of cytochrome P450

Front 26

What do aromatase inhibitors do?

drug

Back 26

Treatment for breast and ovarian cancer that inhibits the aromatase enzyme conversion of androgens to estrogens and thus blocks this step of estrogen synthesis

Front 27

List three SERM drugs.

drug

Back 27

tamoxifen (Nolvadex)
raloxifen (Evista)
toremifene (Fareston)

Front 28

List 4 aromatase inhibitors and their type.

drug

Back 28

anastrozole (Arimidex) - Type 2
letrozole (Femara) - Type 2
exemestane (Aromasin) - Type 1
formestane (Lentaron)

Front 29

Adriamycin

aka. doxorubicin, hydroxydaunorubicin

drug

Back 29

Antitumor antibiotic - inhibits DNA synthesis

anthrocycline antibioitic that intercalates DNA and stops replication

requires iron
toxic to heart muscle and can lead to heart failure

Front 30

Cyclophophamide

drug

Back 30

alkylating agent - inhibits DNA synthesis

can cause hemorrhagic cystitis

Front 31

Herceptin

aka. trastuzumab

drug

Back 31

monoclonal antibody to HER2 receptors - interrupts signaling and triggers apoptosis

HER is responsible for tumor cells developing resistance to chemo

Front 32

paclitaxel

drug

Back 32

mitotic inhibitor

discovered in 1967 by Wall and Wani
originally isolated fromt he bark of pacific yew tree (taxol)

Front 33

What is FOLFOX and what type of cancer do you use it for?

drug

Back 33

combo of flurouracil, leucovorin and oxalplatin

used for adenocarcinoma of the colon

Front 34

Fluorouracil

drug

Back 34

thymidylate synthase inhibitor - blocks synthesis of pyrimidine thymidine and thus stops DNA replication
also methylates deoxyuridine monophosphate (dUMP) to thymidine monophosphate (dTMP)

Front 35

Name the three platinum-based chemo drugs.

Back 35

cisplatin - lung cancer
oxalplatin - part of FOLFOX for colon cancer
carboplatin - advanced lung cancer

-platin!

Front 36

How do the platinum-based chemo drugs work?

Back 36

platinum complexes form in the cells that bind and cause DNA cross-linking and trigger apoptosis

Front 37

Leukovorin

drug

Back 37

folinic acid

adjuvant for methotrexate - helps "rescue" bone marrow b/c it is a derivative of tetrahydrofolate so allows some purine/pyrimidine synthesis to occur

synergistic effect with fluoruricil by inhibiting thymidlyate synthase

part of FOLFOX

Front 38

Avastin

What is another name?
What does it target?
What are the side effects?
What other chemo drug does it improve the effectiveness of?

drug

Back 38

aka. bevacizumab

monoclonal antibody that decreases vascular endothelial growth factor (VEGF) - thus decreases tumor vasculature (tumor growth and metastatic potential)

improves 5-fluorouracil effectiveness by unwinding vessels and permitting access to tumor

can cause severe or fatal hemorrhage (hemoptysis, GI bleeding, hematemesis, CNS hemorrhage, epistaxis, vaginal bleeding)

used with non-small cell lung cancer and adenocarcinoma of the colon

Front 39

FOLFIRI

drug

Back 39

fluorouracil, leucovorin, irinotecan (a topoisomerase inhibitor)

often used with cetuximab

treatment of adenocarcinoma of the colon

Front 40

What chemo drug does the KRAS mutation affect the efficacy of?

drug

Back 40

EGFR mab: centuximab and panitumumab

Front 41

centuximab

drug

Back 41

anti-EGFR monoclonal antibody

Front 42

How are EGFR and VEGF related in tumor cell signaling of angiogenesis?

Back 42

EGFR signals the tumor cell to activate NFkb (nuclear factor) which promotes transcription of lots of cytokines, etc, including VEGF, which promote angiogenesis

Front 43

Rituxan

aka. rituximab

drug

Back 43

monoclonal antibody to CD20 - binds to B cells and triggers apoptosis, antibody-dependent cell-mediated cytotoxicity, and complement activation to lyse the B cells

used to treat non-hodgkin's B cell lymphomas that are CD20 +

Front 44

For nonsquamous (adenocarcinoma and large cell) lung cancer and squamous cell lung cancer, do you use Alimta/cisplatin or Gemzar/cisplatin

drug

Back 44

non-squamous - use Alimta (folate antimetabolite)/cisplatin

squamous - use Gemzar (nucleoside analog)/cisplatin

Front 45

what virus causes smallpox? Is it DNA or RNA?

Back 45

Variola virus - dsDNA

Front 46

true or false, do viruses affect johnny depp?

Back 46

true!

Front 47

What type of vaccine is the polio vaccine?

Back 47

Live attenuated virus

Front 48

What is an example of a cell protein (taken from infected cell) that a virus requires to infect new cells?

hint: a very important virus

Back 48

HIV needs the cell protein cyclophilin

Front 49

Name four routes of entry for viruses and give examples of type of virus that enters this way.

Back 49

1. Respiratory tract - flu, polio
2. Alimentary tract - polio
3. other mucosa, urogenital - HIV and HPV
4. Skin - wounds, bites (arthropods - arboviruses), breaks (papilloma)

Front 50

Papilloma virus
is it RNA or DNA?
what is the structure?
Does it have an envelope?

Back 50

DNA
icosahedral structure
non-enveloped

Front 51

Herpes viruses:
DNA or RNA?
Envelope?
Name the types

Back 51

DNA
Enveloped (icosahedral capsid)
Simplex, varicella zoster (chicken pox), EBV, CMV

Front 52

How do you divide retroviruses into groups based on capsid/membrane morphology on electron microscopy?

Back 52

A: capsid touches membrane
B: capsid pulled away from membrane
C: irregular surface
Avian C: pulled away and irregular

Front 53

Define tropism.

Back 53

Preferentially target specific host species, or specific cell types within those species

Front 54

Define serology (related to viruse).

Back 54

Using antibody binding to specific viral antigenic epitopes to distinguish between viral strains or variants.

Front 55

How does a neutralization assay work?
Antigen capture assay?
Indirect ELISA?
Detecting patient antibodies?

Back 55

Neutralization - antibodies bind up the virus and then it cannot infect cells when added to cell culture

Antigen capture - antibody bound to plate, antigen binds and then another antibody has a marker/enzyme

Indirect ELISA: antigen on a plate (tissue bound to plate), wash with antibodies to that antigen, and then with antibody to that antibody that has a marker.

Detect patient antibodies - antibody to the antibody is bound to a plate, wash with sample, then with antigen, then with antibody marker to that antigen.

Front 56

What two factors are needed for tropism of a virus?

Back 56

1. entry - via virus-receptor interactions (ex. HIV needs CD4)
2. replication permissiveness - cell must contain the correct proteins for the virus to replicate

Front 57

Name the two types of release mechanisms for viruses getting out of a cell and tell how they are related to envelope existence.

Back 57

Cytolysis - non-enveloped viruses
Budding - forms envelope from piece of cell membrane

Front 58

Name the six steps of virus replication.

Back 58

1. attachment
2. penetration
3. uncoating
4. replication
5. assembly
6. release

Front 59

How do you get a live-attenuated vaccine?

Back 59

Isolate human virus, use it to infect monkey cells, allow mutations to accumulate that make it a good pathogen in monkey cells, then use it to vaccinate people.

worry about reversion to pathogenic strain

only type of vaccine that causes full immunity (the others you only get humoral)

Front 60

What type of drug is ribavirin?

Back 60

synthetic guanosine analog

Virus polymerase inhibitor - increases error rate of viral polymerase

used to treat Hep C

Front 61

What three types of virus specific proteins do most antiviral drugs target?

Back 61

RNA dependent RNA polymerase
RNA dependent DNA polymerase
Virus-specific proteases

Front 62

Describe the genome configuration of polio and influenza A. (ie. how many pieces? what type of nucleic acid?)

Back 62

Both are RNA
Polio is unimolecular
Influenza A has 8 segments and is negative sense

Front 63

What is the only double stranded RNA virus?
What is the only single stranded DNA virus?

Back 63

dsRNA = reovirus
ssDNA = parvovirus

Front 64

What type of virus is HCV (hep c)?

nucleic acid type, positive or negative sense, type of reading frame, family

Back 64

+ssRNA, enveloped
translated into one long polyprotein
family Flaviviridae, genus Hepacivirus

there are 11 different genotypes (+ many subtypes) - 1a and 1b are most common in US
leading cause of chronic liver disease in US

Front 65

What presents clinically with spider angiomatas (that go away with pressure but return) and palmar erythema?

Back 65

hepatocellular carcinoma
(you would probably also have jaundice, elevated liver function enzymes)

Front 66

How is Hep C transmitted?

Back 66

mostly through large or repeated percutaneous exposure to infectious blood (injection drug use, donor blood, blood products/organs, needlestick injuries, tatoos, during birth from infected mother) - infrequently through sex and sharign personal items

Front 67

What is Hep C's trophism?

Back 67

Hepatocytes
T and B cells and monocytes in chronic infection

Virus E2 protein, possible receptors are CD81 or LDL receptor

Front 68

What is Hep C's mechanism of disease?

Back 68

infects hepatocytes
not directly cytopathic, cell loss is due to immune destruction

production of Th1 cytokines drives inflammatory response that leads to lesion development and fibrinogenesis

Front 69

Define RNA virus quasispecies.

Back 69

RNA dependent RNA polymerases make lots of errors so an individual type of RNA virus exists as heterogenous mix of closely related virus genomes

Front 70

How does interferon work?

Back 70

Promotes antiviral state by binding to cell membrane receptor and triggering transcription of virus-eradicating intracell proteins and protein synthesis inhibitors.

used to treat hep C

Front 71

What type of virus is Influenza A?

Back 71

-ssRNA, 8 segments (10 proteins), enveloped

family orthomyxoviridae

Front 72

What is the tropism of Influenza A?

Back 72

respiratory tract epithelium

Front 73

What are the two important surface antigens on influenza A and what do they do?

Back 73

Hemagglutinin (HA) (5 subtypes affect humans)- erythrocyte agglutinatior - essential for virus attachment and uptake by host cells - determines virulence/pathogenicity of strain

Neuraminidase (N) (2 subtypes affect humans)- cleaves neuraminidase/sialic acid (part of host cell receptor molecule to which HA attaches) - needed for release of new viruses from infected cell and prevent aggregation

Front 74

What is unique about Influenza A among RNA viruses?

Back 74

It replicates in the nucleus! (steals 5' cap from exiting host mRNA)

Front 75

3 requirements for a pandemic

Back 75

1. new virus with little/no immunity in the population
2. can replicate in humans and cause disease
3. efficiently transmitted person to person

Front 76

Neuraminidase inhibitors

Back 76

Flu treament
only for patients over 7 years old
relenza (zanamivir)
tamiflu (oseltamivir)
treats both flu A and B

Front 77

Rimantadine

Back 77

blocks early step in replication cycle of Influenza A only

Front 78

Amantadine

Back 78

Flu treatment
blocks viral particle uncoating and release of genomic material into host cell

Front 79

How long can flu virus live on a surface?

Back 79

2-8 hours

Front 80

What type of vaccine is Flu-Mist?

Back 80

live-attenuated nasal spray
induces neutralization and mucosal antibodies but T cell immunity is unknown

Front 81

What is unique about poxviridae among the DNA viruses?

Back 81

It replicates in the cytoplasm (most DNA viruses replicate in nucleus)!

it is also the biggest DNA virus

extra info: has a strong capsule that resists dessication (can be transferred on fomites)

Front 82

What type of anemia does parvovirus B19 cause?

Back 82

aplastic anemia

Front 83

What is the virus structure of CMV?

Back 83

herpes virus
lipid envelope, tegument and icosahedral capsid
DNA and preformed mRNA

Front 84

What is the tropism of CMV?

what is required for attachment to host cell and what is the (possible) receptor?

Back 84

broad tissue tropism but especially glandular, CNS and hematopoetic cells

requires tethering via heparan sulfate proteoglycan

receptor may be epidermal growth factor receptor (EGFR)

Front 85

What is the CPE (cytopathic effect) of CMV?

Back 85

enlarged cells with nuclear (with characteristic clearing) and cytoplasmic inclusions

Front 86

Symptoms of congenital CMV.

Back 86

cytomegalic inclusion disease (CID)
periodic symptoms throughout life
CNS effects: cerebral calcification, hearing and vision loss, mental retardation
trombocytopenia - causes petechial rash and purpura (blueberry muffin)

Front 87

How is CMV transmitted?

Back 87

body fluids - saliva, sexual transmission is possible, blood transfusions, transplant
transplacental or post-natal (infected genital secretions during birth or breast milk)

Front 88

What infection is the main cause of death in AIDS patients?

Back 88

CMV! causes pneumonitis, AIDS dementia, blindness from retinitis

Front 89

What are the treatments for CMV?

Back 89

none for healthy people (even pregnant women)

in severe immune compromised or congenital CMV: gangciclovir and valganciclovir (guanosine analogs, polymerase inhibitors) - strong side effects

Front 90

What are the two classes of retroviruses?

Back 90

oncornavirinae - imortalizes cells - ex. human T cell leukemia virus (HTLV1 and 2)

lentavirinae - slow viruses - neurologic and immunosuprresive - ex. HIV

Front 91

What is the tropism for HIV and what two glycoproteins are involved and what are their functions?

Back 91

tropism for CD4+ T cells, macrophages, and epithelial cells

envelope GP120 binds CXR4 on T cells and CCR5 on macrophages - cell attachment

transmembrane GP41 - induces viral-cell fusion

Front 92

What is another name for pneumocystis carnii

Back 92

pneumocystis jirovecii

Front 93

What is the name of the core protein of HIV?

Back 93

p24 - levels in blood are measured and correlate with extent of disease progression

Front 94

What level of CD4+ corresponds with AIDS classification?

Back 94

CD4 < 200/microliter

Front 95

What are the symptoms of AIDS?

Back 95

CMV ulcers in GI and malnutrition -> HIV wasting syndrome
pneumocystis jirovecii pneumonia
mycobacterium avium
Kaposi's sarcoma (herpes 8 virus)
opportunistic infections
CNS disease
severe CMV

Front 96

Nucleoside analogue reverse transcriptase inhibitors

Back 96

azidothymidine (AZT), dideoxyinosine (ddl),dideoxycytidine (ddc), d4T, 3TC

Front 97

HIV protease inhibitors

Back 97

sawuinavir, ritonavir, indinavir, nelfinavir

Front 98

What is HAART?

*hint, think AIDS

Back 98

highly active anti-retroviral therapy

cocktail of 3+ drugs: nucleoside analogues (or other RT inhibitor) and protease inhibitors

ex. AZT, indinavir and 3TC

Front 99

What is an HIV provirus?

Back 99

when it has been reverse transcribed to DNA but not yet integrated (part of pre-integration complex)

Front 100

name the three types of protozoans and examples of each

Back 100

1. flagellates: giardia lamblia
2. amoebas: entamoeba histolytica
3. sporozoa: plasmodium, toxoplasma, cryptosporidium

Front 101

toxoplasma gondii

where does it come form?
what are the two lifecycle forms?
symptoms?

Back 101

tachyzoites cause acute infection
bradyzoites can cause cysts in muscle and nerve tissue and latent infection, reactivation

cats are the definitive host
humans aquire it from undercooked meat of animals that have been fed with contaminated cat feces or eating food contaminated with cat feces

can be mono-like or typhus-like symptoms - mostly asymptomatic in healthy ppl
TORCH syndrome (causes brain necrosis and calcifications, psychomotor retardation, seizures, deafness, microencephalopathy, micro-opthalmia, jaudice, hepatosplenomegaly, etc etc.)
AIDS patients with CD4<100 - very sever, multifcocal necrotizing enecephalitis

Front 102

What is a trophozoite?

Back 102

Pathogenic form of parasite that only develops in favorable environments
has a short life span
found in symptomatic patient - mostly in liquid, diarrhetic stools

Front 103

Giardia lamblia

Back 103

flagellated protozoan
causes sever diarrhea
found in wild animal feces - cysts contaminate water sources

Front 104

What is a cyst?

Back 104

Form that does not feed or reproduce, can survive outside of host, and if formed because of inhospitable environment
passed in stools of asymptomatic patient - transmitter of infection

Front 105

Entamoeba histolytica

Back 105

Amoeba
Causes ulcerative colitis
Button-hole ulcers - "flask-shaped" deep, extensive ulcer undermining normal mucosa below the "button hole"
trophozoite destroys PMNs and tissue cells via parasitic lectin
oral-fecal transmission

can get to liver by perforating bowel, getting into blood and traveling via portal vein

Front 106

What are the characteristics of strongyloides hyperinfection?

Back 106

Often triggered by immune suppression (ie. high dose corticosteroids)

flattening of villi, congestion, and inflammation of lamina propria of small intestine

intra-alveolar hemorrhage and foci of neutrophilic exudates in the lungs

enteric bacterial sepsis and respiratory failure

Front 107

Taenia solium

Back 107

eating eggs gives you a larval infection (more dangerous)

cysticerci = larval form - forms translucent cysts in the brain

can get from food contaminated with human feces

treat with mebendazol and surgery

Front 108

Echinococcus granulosus

Back 108

get from food contaminated with dog/wolf feces

larval form = hydatid cysts - travel to liver or brain

Front 109

Leishmaniasis

Back 109

trypanosome protozoa

cutaneous cases in Middle East

can become disseminated infection in immunosuppressed and infect macrophages/mononuclear phagocytes - leasd to acute phase cytokine reactions and wasting/cachexia

look for amastigotes (Leishmania form) containing rod-shaped mitochondria (kineoplast)

transmitted by sand fly

Front 110

What parasite can phagocytize RBCs?

Back 110

Entamoeba histolytica

Front 111

What is unique to the cell wall and cell membrane of fungi?

Back 111

cell wall = chitin and glucan
cell membrane = ergosterol

Front 112

Types of asexual reproduction in fungi.

Back 112

infective forms: budding, fission, endosporulation, hyphal elongation
saprophytic/culture forms: fruiting head with formation of conidia or sporangiospores

Front 113

Candida albicans

Back 113

endogenous
infections are caused by overgrowth
superficial infection = thrush but can also be localized invasive or disseminated invasive (rectal ulcers, vascular invasion)

Front 114

Cryptococcus neoformas

Back 114

exogenous - inhalational spread
pigeon poo
in T-cell immunosuppressed - meningoencephalitis, pulmonary infection - nodules and localized granulomas (a cutaneous presentation would mean systemic dissemination from the lungs via blood stream)

Front 115

Aspergillus

Back 115

mould
inhalation from soil and decaying veggies
broad disease specturm - respiratory/sinus infection, disseminatited/invasive, allergies, granulomas, fungus ball (non-invasive in pre-existing lung cavities)