Genetic Disease Flashcards
What are karyotypes and how many autosomes do humans have?
karyotypes = complete visual set of chromosomes
22 autosomes
(1 sex chromosome)
Describe gene penetration
frequency of expression of a gene (can relate to characteristics or diseases)
7 out of 10 patients have OI w reduced bone density, what percent penetrance is that?
7 out of 10 = 70% penetrance
What is it called when every generation has some aspect of a disease?
fully penetrant
What is it called when not every individual shows the same characteristics?
variable expressivity
T/F congenital anomalies are defects in single gene disorders, chromosomal anomalies, or multi-factorial disorders
TRUE
What changes occur in single gene disorders?
change in gene in ovum or sperm or changes in body cells
What disease is congenital but signs appear in adulthood?
Huntington’s disease
How do chromosomal anomalies occur?
errors in meiosis (deletions or translocations)
Explain Trisomy 21 and what it causes:
3 chromosomes at position 21 instead of 2
Down’s syndrome
Low levels of ____ in mother’s causes spina bifida
folic acid
In order to decrease spina bifida in live births, what was added to a food product?
Folate in flour (in the UK)
Similar ex: salt was iodized for iron deficiency in America
What happens when a baby has spina bifida?
spinal processes don’t fuse causing spinal cord and meninges to herniate
Teratogenic agents cause damage to what? Give an example:
damage to DNA in embryo/fetal stage
teratogenic agent ex = Thalidomide
Why was Thalidomide developed and why did pregnant mothers take it?
to help soldiers sleep anxiety after WW2
husbands gave it to pregnant wives to help them sleep and discovered it “resolved” morning sickness
What is phocomelia?
malformation of limbs or missing limbs
Seen with Thalidomide drug use
What does it mean if a drug is used “off label”?
use of a drug for condition other than what it was approved of.
FDA regulation = Dr. Francis Kelsey
What are multifactorial illnesses and give two examples:
genetic + environmental
hard to treat
ex:
breast cancer
atherosclerosis
Single gene disorder occurs in how many live births?
1 in 200
What are some single gene disorder examples?
color blindness, Marfan syndrome, CF, etc.
Describe Marfan syndrome:
skeletal deformities
pectus carinatum “pigeon chest”
long digits
long wing span
T/F both parents have to be a carrier of an autosomal recessive disorder
TRUE
(child = homozygous for gene)
What does PKU stand for and what’s another name for it?
phenylketonuria
(aka hyperphenylalaninemia)
Hyperphenylalaninemia is a deficiency in what?
phenylalanine hydroxylase
Phenylalanine converts to what (with the help of an enzyme)?
tyrosine
If phenylalanine can’t convert to tyrosine, what happens?
Accumulation of phenylalanine = PKU (phenylketonuria)
What is a normal level of phenylalanine?
0.06 - 0.1 mol/L of blood
T/F inherited mental deficiency is an effect of PKU
TRUE
What population is PKU most prevalent in?
Yemenite jews 1:5000
When should you screen newborns for PKU?
1-3 days after birth
List four sx of PKU:
growth retardation
mental deficiency
eczema (idiopathic)
recurrent seizures
When should you start treatment if a pt has PKU?
start before 3 weeks of age
What is the main treatment for PKU?
Low phenylalanine diet INDEFINITELY
What level of phenylalanine is seen in pt’s with PKU?
1 mol/cc of blood
A fetus can not be exposed to how many mmol of phenylalanine?
no more than 0.36 mmol of phenylalanine
What happens to a fetus that has been exposed to high levels of phenylalanine?
microcephaly, growth retardation, congenital heart disease
List 3 metabolic reasons for why tyrosine is important:
gluconeogenesis
protein synthesis
melanin catecholamines
Pt’s with PKU have a decrease in melanin catecholamines, what does this cause?
hypopigmentation
Pt’s with PKU cannot synthesize tyrosine from phenylalanine bc of a severe deficiency of the hepatic enzyme phenylalanine hydroxylase, what does this cause?
decreased protein synthesis
decreased gluconeogenesis
hypopigmentation
Why do pt’s with PKU have neurologic problems?
increased phe inhibits transport of neural a.a. across BBB
deficiency of a.a. in csf = neurologic problems
In autosomal dominant disorders, babies will be affected if they have how many alleles?
only ONE allele
Name 3 autosomal dominant disorders:
Osteogenesis imperfecta
Huntington’s disease
Marfan syndrome
In OI, what percent of cases occur due to a problem with the COL1A1 and COL1A2 genes?
90% of cases
What genes do you need to synthesize subunits of type 1 collagen?
COL1A1 & COL1A2
What is the only collagen found in bone?
type 1 collagen
Where is type 1 collagen found?
- bone
- dermis of skin
- connective tissue capsules of most organs
- adventitia of GI tract
- blood vessels
Type 1 collagen is made up of how many strands/what are they?
3 strands:
- 2 strands are alpha 1 strands encoded by COL1A1 gene
- 1 strand is alpha 2 encoded by COL1A2 gene
What forms the triple helix in type 1 collagen that strengthens bone?
The 3 strands:
-2 strands of alpha 1 encoded by COL1A1
- 1 stand of alpha 2 encoded by COL1A2
Name the 4 types of osteogenesis imperfecta
type 1 - mild
type 2 - perinatal lethal
type 3 - progressive deformity
type 4 - deforming w normal scleras
Type 1 OI is caused by…
a decrease in type 1 collagen due to a single base pair change (aka premature stop codon, also known as nonsense mutation)
What is another name for a premature stop codon?
nonsense mutation
Name 1 sx all pt’s with osteogenesis imperfecta have no matter the type?
hearing loss due to ossicles and cochlea
List the characteristics of type 1 OI:
- fx in childhood
- blue scleras
- short stature
- dentinogenesis imperfecta (dysplasia)
- hearing loss
Type 2 OI is caused by…
abnormal forms of type 1 collagen w decreased triple helix formation
List the characteristics of type 2 OI:
- babies have fx in uterus
- x-ray shows beaded ribs
- die in infancy
- hearing loss
Which type of OI is considered lethal?
type 2 (babies die in infancy)
Type 3 and 4 OI is caused by…
deletion in COL1A1 & COL1A2 genes + problems w non-helical part of collagen
List the characteristics of type 3 OI:
- multiple boney deformities
- continuous fx throughout lifetime
- eventually become non ambulatory
- blue scleras
- dentinogenesis imperfecta
- hearing loss
List the characteristics of type 4 OI:
- short stature
- more fx than type 1
- not as many boney deformities as type 3
- normal or gray scleras
- hearing loss
T/F type 1 OI causes more fx than type 4:
FALSE - type 4 OI causes more fx than type 1
T/F type 3 OI causes more boney deformities than type 4:
TRUE - type 4 doesn’t have as many boney deformities as type 3
Name an x-linked dominant disorder:
Fragile X Syndrome
What disorder is the most common cause of mental deficiency and learning disorders in the US?
Fragile X Syndrome
What causes Fragile X Syndrome?
X chromosome has indentation, which causes decrease in condensation
How many boys and girls are affected by Fragile X Syndrome?
1:1500 boys
1:8000 girls
Why are boys more affected by Fragile X Syndrome than girls?
boys only have 1 X chromosome, which is mutated, compared to girls who have two X chromosomes
Who is the primary carrier of the FXS gene?
Females will always be carriers because they have a normal X chromosome
Name 2 X-linked recessive genetic disorders, that are inherited through a genetic defect on an X chromosome and manifested in heterozygous males:
Duchenne’s Muscular Dystrophy & Hemophilia
In FXS, 20% of male carriers do not manifest the disease. Why?
- a triplet that repeats itself (CGG)
- if male has 60-200 repeats, disease is not manifested (unknown why)
In boys with FXS, development slows down in what age?
1-2 years old
Boys who have FXS display what clinical characteristics?
- large testes
- changes in facial features in adolescence
Why do girls with FXS have mild mental deficiency?
because they have one normal X chromosome
What are three chromosomal disorder examples?
- Turner syndrome (monosomy X)
- Klinefelter’s syndrome (polysomy X)
- Down’s syndrome (trisomy)
What is a characteristic in girls with Turner syndrome and how many chromosomes do they have?
no ovaries, physical deformities
45 chromosomes (only 1 X chromosome)
What is a characteristic in boys with Klinefelter’s syndrome and how many chromosomes do they have?
small testes (don’t produce sperm)
47 chromosomes (2 X chromosomes)
What is the most common chromosomal disorder and explain its chromosomal anomaly?
Trisomy 21 - 3 chromosomes at location 21 (47 chromosomes)
Down’s syndrome is characterized by 3 primary symptoms, what are they?
growth retardation
immunodeficiency
mental deficiency
Down’s syndrome presents in how many live births and accounts for how many mental deficiencies?
1 in 700 live births
1/3 of all mental deficiencies
The prevalence of down’s syndrome increases with what?
maternal age
What test can detect Down’s syndrome in the uterus?
amniocentesis
What are the three theories of Down’s syndrome?
egg degeneration
environmental factors
paternal age
List several characteristic that children with DS have:
- developmental delay**
- small heads**
- growth retardation**
- slanted eyes w brushfield spots**
- small hands w deep palmar crease**
- hypotonic muscles**
- loose joints
- short stature
- wide space between 1st (hallux) and 2nd toes**
- delayed/incomplete sexual development**
- short 5th finger**
- small ears
- flat occiput**
- tendency to develop cataracts
- mouths hang open w protruding tongues (thicker)
- hearing problems
- cardiac problems
- ECD (endocardial fusion defect)
- Alzheimer’s when older
What is another name for slanted eyes?
mongolism
Why are brush field spots often seen in DS?
connective tissue laid down in iris
What is endocardial cushion defect?
wall between chambers of heart are thin
What are the two main branches of the immune system?
non-specific (innate)
specific (acquired)
What is the non-specific immune system composed of?
physical barriers, cellular barriers, and complement
Cellular= phagocytes, macrophages, lymphocytes, and WBCs
WBCs (granulocytes)= basophils, neutrophils, eosinophils
What is the specific immune system composed of?
B cells (antibodies) and t-cell mediated immunity
Name 2 passive barriers and their purpose:
physical and chemical barriers
= 1st line of defense
What are the 5 physical & chemical barriers?
- skin
- sebaceous glands
- tears
- gastric juices
- mucus membranes
Describe the function of the skin as a passive barrier:
effective barrier bc of keratin in epithelium
Describe the function of sebaceous glands as a passive barrier:
inhibit bacterial growth through the release of fatty acids
Describe the function of tears as a passive barrier:
contains the enzyme lysozyme that kills bacteria
Describe the function of gastric juices as a passive barrier:
juices are acidic and help kill bacteria
Describe the function of the mucous membranes as a passive barrier:
lines airways & traps microorganisms
If physical barriers of the immune system are breached, which cells take over?
macrophages
phagocytes
lymphocytes
granulocytes (WBCs- neutrophils, basophils, eosinophils)
What are the three types of granulocytes?
basophils
neutrophils
eosinophils
What are complement proteins?
a family of 25+ inactive plasma proteins produced by the liver activated in a cascade system by 2 different pathways
Complement proteins activate a cascade system of 2 different pathways, what are they?
classical & alternative
The classical pathway of complement proteins are activated by what?
immune complexes (when antibody combines w antigen)
What are the most common antibodies in the immune complex of the classical pathway of complement proteins?
IgG & IgM (stimulate complement)
Which two antibodies simulate the classical pathway in complement proteins?
IgG & IgM
The immune complexes in the classical pathway activate what complement protein?
C1q
After the immune complexes bind to C1q in the classical pathway of complement proteins, ___ ___ is activated:
C3 convertase
The alternative pathway of complement proteins are activated by what?
bacterial endotoxins & fungal surfaces
T/F the alternative pathway of complement proteins doesn’t need an immune complex to be activated
TRUE
C proteins act as opsonins for the purpose of what?
opsonins coat pathogens to recognize phagocytes, this helps attract leukocytes
C3 convertase cleaves into C3a and C3b to start what pathway?
common pathway
How does the common pathway of C proteins start?
when C3 convertase cleaves into C3a and C3b
C proteins can cause what two types of cells to degranulate and stimulate inflammation?
mast cells and basophils
Some C proteins come together and form MAC. What is a “MAC” and which C proteins are involved?
MAC = membrane attack complex
C proteins that form MAC = C5b, C6, C7, C8, C9
What is the function of a membrane attack complex (MAC)?
to attack membranes of pathogenesis and punch holes in them causing water to get in and lyse the cell
Acute phase proteins are what type of proteins?
plasma proteins produced by the liver
What cells are inadequate without T cells and produce antibodies?
B cells (inadequate without T cells & produce antibodies when activated)
Name the 4 kinds of inflammation in the non-specific system:
edema
erythema
localized warmth
localized pain
What are the two types of T cells?
T cytotoxic (CD8) & T helper cells (CD4)
What T helper cell is targeted by HIV causing HIV+ patients to lose 2/3 of their immunity?
CD4
What is another name for cytotoxic T cells?
CD8 cells
What proteins act as opsonins, enhance the inflammatory system, and act as antiprotease molecules?
acute phase proteins (aka plasma proteins)
T/F plasma protein production is decreased during the acute phase of injury or invasion by a pathogen?
FALSE production is increased
What autoimmune disease can occur if acute phase proteins don’t decrease?
Rheumatoid arthritis (huge levels of inflammation)
What is CRP and when do you check it?
C-reactive protein (a type of acute phase protein)
Check CRP for pt’s you suspect w arthritis
Increased CRP can increase the risk of what?
heart disease
Describe the mechanism of inflammation:
- inflammation attracts immune cells
- sets stage for area to become repaired
- provides barrier to spread and promote tissue repair
What activates complement?
invading pathogens
In inflammation, mast cells will degranulate and release what?
histamine
T/F mast cells increase capillary permeability:
TRUE (they’re a vasodilator)
Increased permeability causes ____ to get out of blood vessels, which causes erythema, vasodilation, and warmth?
leukocytes
Macrophages need what to digest and phagocytize bacteria?
can’t recognize w/o capsules
(need an opsonin to phagocytize)
The specific system is also called what system?
adaptive or acquired
T/F the specific system has memory:
TRUE
The specific system contains what two types of cells?
T cells + B cells
What differentiates into plasma cells and recreates antibodies?
B lymphocytes
What are the 5 classes of antibodies?
M - IgM
A - IgA
D - IgD
G - IgG
E - IgE
How many antibody chains are there and describe the basic structure of an antibody?
- 2 identical light chains
- 2 identical heavy chains (Y)
Y structure is basic structure of antibody
1 Y structure = 2 binding sites
An antigen binding site is called a what?
Fab
What antibody is the most abundant with the longest half life?
IgG
Which antibody is small enough to cross the placenta?
IgG
Which antibody binds to mast cells and basophils?
IgE
Which antibody binds on immature B cells?
IgD
Which antibody is a pentamer and is the first produced in an immune response?
IgM
Which antibody has 10 binding sites and can stimulate complement the most?
IgM
Which antibody is a loner in serum but a dimer in secretions?
IgA
Which antibody is found in tears, saliva, semen, bile, and, colostrum
IgA
What is colostrum?
mom’s first milk
What is a dimer?
2 Y’s together
What do T helper cells do?
secrete cytokines
What do cytotoxic T cells do
secrete cytotoxic substances
What is the ratio of T helper to cytotoxic T cells?
2:1 (more T helper cells)
What are the functions of T cells?
- respond to tumor cells
- bind to viruses
- respond to piece of antigen presented by another cell
Cells that are being “presented” are called what?
APCs (antigen presenting cells)
What are TCRs and what are their accessory molecules?
TCRs = T-cell receptors
accessory molecules = CD4 & CD8
How do you know if a cell is a T helper cell?
- has a CD4 receptor
- secretes cytokines
What are the 3 cytokines that T helper cells secrete?
- IFNY (interferon gamma)
- ILs (interleukins)
- CSF (colony stimulating factors)
What does the cytokine interferon gamma (IFNY) do?
- helps B cells proliferate quicker
- activates macrophages
- activates NK cells (natural killer cells)
What do interleukins (ILs) cytokines do?
help B cells produce antibodies faster
What is the function of colony stimulating factor (CSF) cytokines?
stimulating productions of all WBCs
What are the 2 subtypes of T helper cells?
Helper cell 1 & Helper cell 2
How do you differentiate between helper cell 1 and helper cell 2 in T cells?
dependent on the cytokines they are releasing
When T helper cells bind to APCs what receptor must they have?
MHC class II receptor
T helper cells & CD4 molecules only recognize what MHC class?
class II MHC
Cytotoxic T cells & CD8 molecules only recognize what MHC class?
class I MHC
Cytotoxic T cells produce cytotoxic substances called what?
perforins
What do perforins do?
perforate pathogens + produce granzymes (digestive enzymes)
T/F both B cells and T cells produce memory cells
TRUE
B cells recognize antigens on follicular dendritic cells in _____ centers?
germinal centers
What do interferons do?
activate macrophages & produce NK cells
Describe the primary immune system:
reaction of immune system when it contacts antigen for first time
Y/N Does the primary immune system have a lag phase?
YES
In the primary immune system, IgM peaks when?
after a week
In the primary immune system, IgG peaks when?
after 2 weeks
Describe the secondary immune system:
reaction of immune system when it contact antigen for second + subsequent times
Y/N Does the secondary immune system have a lag phase?
NO - instanty produces antibodies (immediate response)
Acquired immunity can be passive or active, describe ‘natural passive’ and give examples:
antibodies are given
ex:
- mother to fetus across placenta
- mother’s milk
doesn’t make memory cells
Does baby make memory cells from mother?
no
Acquired immunity can be passive or active, describe ‘artificial passive’ and give examples:
antibodies are given
ex:
snake bite / rusty nail
doesn’t make memory cells
Acquired immunity can be passive or active, describe ‘natural active’ and give examples:
you are making antibodies
ex:
chicken pox / cold/flu
Acquired immunity can be passive or active, describe ‘artificial active’ and give examples:
pathogen is given
ex:
vaccines
What are hypersensitivity reactions and how are they classified?
- when immune system results in pathological changes in the host tissue
- classified by Gell & Coombs (4 types)
What are the 4 types of hypersensitivity?
Type I Immediate
Type II Cytotoxic
Type III Immune Complex-Mediated
Type IV Cell-Mediated or Delayed
What antibody is type I rxns mediate by and what happens?
IgE is released and binds to mast cells in response to harmless stuff (ex: pollen, animal dander)
List 3 rxns that can happen in type I hypersensitivity
- allergies
- food
- anaphylaxis
What causes an allergic response?
allergens
Explain the mechanism of subsequent allergen exposures:
- allergen binds to IgE on mast cells
- mast cells degranulate
- degranulation releases histamines
- vasodilation occurs
- inc. capillary permeability
When histamines, a vasodilator, are released capillary permeability is increased. What does this cause?
- edema
- erythema
- pruritus (close to nerve endings)
- bronchoconstrictor
If mast cells are present in nasal mucosa what does this cause?
allergic rhinitis (hay fever)
If mast cells are present in the lungs what does this cause?
asthma
What is the treatment for allergies?
antihistamines
List the manifestations of allergic rhinitis:
- paroxysmal sneezing (uncontrollable)
- pruritis
- mucus hyper secretion (nasal congestion)
What is the treatment for mucus hypersecretion?
decongestant
In children with allergies you’ll see periorbital edema. What is this in layman’s terms?
allergic shiners
What are the complications of allergic rhinitis?
sinusitis & otitis media
In pt’s with food allergies, where are histamines released and what is usually seen on their skin after a reaction occurs?
- mast cells release histamines in GI tract
- large erythematous plaques
What sx do pt’s with food allergens present with?
nausea, vomiting, diarrhea
What type of reaction is an anaphylaxis?
systemic
How do you treat anaphylaxis?
EpiPen
What happens in the body of a pt experiencing anaphylaxis?
- decreased BP (blood vessels vasodilate)
- trouble breathing (bronchodilator)
What is the most common cause of anaphylaxis?
insect bites
If a pt has a severe reaction to local anesthesia, what should you do?
give epinephrine (vasoconstrictor + bronchodilator)
What happens in type II cytotoxic hypersensitivity reactions?
IgG or IgM binds to antigens in cell membranes that activate complement
Give an example of type II cytotoxic hypersensitivity:
incompatible blood transfusion
How is type III immune complex hypersensitivity reactions mediated?
mediated by the formation of antigen-antibody aggregates called immune complexes
What happens if the immune complexes in type III hypersensitivity is not phagocytized quickly?
immune complexes will accumulate in blood vessels and cause a delayed reaction
Complement comes in to destroy immune complexes after a delayed reaction in type III hypersensitivity. What does this do to blood vessels and surround tissue?
destroys them causing vasculitis
Give an example of type III immune complex-mediated hypersensitivity and explain what happens when this occurs:
glomerulonephritis = vasculitis = destroyed capillaries of kidneys
In type IV cell-mediated or delayed hypersensitivity reactions, T cells are activated by _____ and release _____ resulting in inflammation and tissue damage
antigens, cytokines
Give an example of type IV cell-mediated or delayed hypersensitivity:
latex gloves, poison ivy, TB test
What is the treatment for type IV hypersensitivity? (hint: latex gloves, poison ivy, TB test)
corticosteroids
What is happening in the body in autoimmune diseases?
the body can’t differentiate self-antigens from non-self antigens
Some autoimmune disease are caused by ______ that destroy tissue while some are caused by ____ that attack tissue
- autoantibodies (destroy tissue)
- T cells (attack tissue)
Give an example of two autoimmune diseases caused by autoantibodies destroying tissue:
- myasthenia gravis
- hyperthyroidism (Graves’ disease)
Give an example of an autoimmune diseases caused by T cells attacking tissues:
multiple sclerosis (MS)
What is SLE (systemic lupus erythematosus) and what are its sx?
chromic, inflammatory illness affecting multiple systems
sx:
- rash across cheeks & nose “butterfly rash”
- severe ply arthritis
- renal failure (from glomerulonephritis)
- carditis / pericarditis
- anemia
- pleurisy
Why do patients with SLE have severe joint pain?
pain is caused from inflammation due to deficiency in complement proteins to clear the immune complexes
The deficiency in complement proteins in pt’s with SLE causes blood cells to be destroyed. What does this lead to and what does it affect?
- leads to vasculitis, ischemia, necrosis
- affects kidneys, lungs, GI tract, joints
How do you diagnose a pt who you suspect has lupus?
- ANA test (antinuclear antibodies in serum = autoimmune rxn)
- LE cell test = lupus erythematosus cell = neutrophil w nuclear material
- Sed rate test (inc. sed rate = chronic inflammation)
What specialist should you refer a pt with lupus to?
rheumatologist
What is the treatment for pt’s with lupus?
- prednisone
- NSAIDS
- antimalarials (hydrochloroquine - Plaquenil)
- immunosuppressive (methotrexate = Rheumatrex)
What is a milder form of lupus called?
discoid lupus erythematous (DLE)
In the milder form of lupus (DLE) what organ does it affect and who is it more commonly present in?
- only affects skin
- more common in women (some men) ages 20-40 y/o
- hispanic/ AA/ asian
In lupus, the body develops antibodies against own what? (hint: considered anti-nuclear antibodies)
platelets, RBCs, DNA, & other nuclear material
(this is what ANA is testing)
What is an immunodeficiency disorder?
partial or complete loss of fxn of immune system
Immunodeficiency disorders can be ____ or ____, or ____ or ____
acute or chronic
primary or secondary
Primary immunodeficiency disorders are ____ and cause a defect in what cells?
- genetic
- defect in phagocytic cells, complement, lymphocyte fxn
Primary immunodeficiency disorders are found in children and cause what type of problems?
developmental problems
List 3 primary immunodeficiency disorders:
- SCID
- DiGeorge syndrome
- X-linked agammaglobulinemia (XLA)
What is SCID (severe combined immunodeficiency)?
- near/ or complete lack of both immune systems
- very little specific & non-specific
- die by age 2 “bubble children”
What is DiGeorge syndrome?
congenital thymic hypoplasia (thymus doesn’t develop)
In DiGeorge syndrome, the thymus doesn’t develop. Why is this?
lack of T cells
(the thymus is where T cells mature)
What is XLA (X-linked agammaglobulinemia)
inability to produce B cells or antibodies that make B cells
Pt’s with XLA lack the antibody aspect of what immune system?
specific system
What is the most common cause of secondary immunodeficiency disorders?
malnutrition
What can cause secondary immunodeficiencies?
- splenectomy
- tumors
- chemotherapy / radiation
- immunosuppressive drugs
- liver disease
- long term use of prednisone
- lymphoid atrophy
- infection (HIV)
What is the largest lymphoid organ?
spleen
Immunodeficiencies predisposes a pt to what?
opportunistic infections
T/F in immunodeficiencies, a pt’s own bacterial flora can take advantage and become opportunistic
TRUE
What should you prescribe a pt with an immunodeficiency before any medical/dental procedure?
prophylactic abx
(this includes lupus pt’s who have been on prednisone for years!)
What is AIDS (acquired immunodeficiency syndrome)?
a chronic disease caused by HIV that destroys T helper cells
Describe the latent phase in AIDS
pt is HIV+ before developing AIDS
(may last many years - asymptomatic)
The active infection phase of AIDS is indicated by what?
a low CD4 count
What is HIV (human immunodeficiency virus)?
a group of retroviruses whose RNA encodes for 9 genes & is part of the lentivirus subfamily
HIV-1 is most prominent where?
North America (NY + MIA) & Europe
HIV-2 is most prominent where?
West Africa
Why is HIV so hard to treat?
- can mutate inside a person
- tropism (coreceptor unique to each HIV strain)
What two cells does HIV infect?
- CD4 T helper cells
(cell number + fxn decrease) - macrophages
(affects microglial in brain)
All HIV strains express what protein that binds to CD4 receptors?
gp120
Describe the mechanism of HIV infection:
- RNA strand enters cell
- uses reverse transcriptase enzyme to convert RNA to viral DNA
- Viral DNA binds to your DNA & tells T helper cells to make more of virus
What is tropism?
coreceptor different for specific strains
HIV antibodies peak at how many weeks?
2 weeks “lag phase”
Why is HIV transmission from blood “better” than HIV transmission via sex?
infection via blood = body will immediately start producing antibodies
A pt is diagnosed with aids when their CD4 count at what level?
<200 CD4 T helper cells/cc of blood
(ratio of 2:1 disappears)
List the ways HIV can be transmitted:
- blood
- sexual
- vaginal discharge
- mom to fetus
- IV drug use
- mother’s milk
What drug has decreased transmission from mother to fetus?
AZT (azidothymidine)
If a baby is born with HIV antibodies, does this mean baby is HIV+?
No, usually baby will have no antibodies at 3-4 weeks
(if mother is HIV+ baby is put on antiretroviral when born)
What are fomites?
inanimate objects
At what degrees is HIV inactivated and for how long?
> 60 degrees C for 20 minutes
How many stages of HIV are there?
3
Describe stage 1 of HIV:
mild, flu-like sx (fever, sore throat)
(resolves w/o tx, no idea pt is HIV+)
Describe stage 2 of HIV:
long, latent phase - maybe lymphadenopathy
(7-10 years)
Describe stage 3 of HIV:
immune system is severely damaged
(AIDS + all complications)
What are some effects of AIDS?
- GI problems
- necrotizing periodontal disease
- encephalopathy
- sensory, motor, & inflammatory polyneuropathies
- death due to secondary infections
A pt with AIDS may have diarrhea due to what?
infectious enterocolitis associated w CD4 lymphopenia & opportunistic infectious agents
What is necrotizing periodontal disease?
tissue destruction of gums and bone
HIV encephalopathy is an HIV associated neurocognitive disorder characterized by short term memory loss & personality changes. What can this develop into?
AIDS dementia characterized by loss of coordination & progressive memory loss
(due to infection of microglia)
Pt’s with HIV may present with sensory, motor, & inflammatory polyneuropathies. These polyneuropathies are due to what?
axons of nerves are destroyed
In AIDS, death due to secondary infection is most commonly due to what fungus which causes what life threatening infection?
pneumocystis jirovecii (fungus - spores in sputum)
causes SEVERE pneumonia
List several secondary infections that pt’s w AIDS could die from?
- pneumocystis jirovecii
- herpes simplex
- candida “thrush”
- TB
- cancer
Pt’s w AIDS have a higher incidence of TB and cancer than pt’s w/o AIDS. What is the most common type of cancer found in pt’s w AIDS?
What is the second most common type of cancer?
most common = Kaposi’s sarcoma
second most common = Non-Hodgkin’s lymphoma
Describe the presentation on Kaposi’s sarcoma and where does it develop?
- purple-brown, painless, non-pruritic patches on skin
- can occur in lungs, liver, & GI tract (chronic hemorrhaging
What is the oldest HIV drug and what does it do?
AZT - blocks transcription
What HIV medication blocks protein syntheses? Give two examples:
protease inhibitors
(Saquinavir & Ritonavir)
What HIV medication inhibits viral DNA? Give an example:
viral integrase inhibitors
(Raltegravir)
What HIV medication prevents fusion of HIV to body cells? Give an example:
fusion inhibitors
(Enfuvirtide)
HIV pt’s are given a cocktail of medications called what? What do these medications do?
- HAART (highly active antiretroviral therapy)
- keep viral load low & keep pt in latent stage
What are the 5 medications available for HIV treatment?
- AZT
- protease inhibitors
- viral integrase inhibitors
- entry inhibitors
- fusion inhibitors
The recognition of processed antigen by specialized T lymphocytes known as what?
helper T (CD4) lymphocytes
Helper T lymphocytes recognize processed antigen displayed by APCs only in association with polymorphic cell surface proteins called what?
major histocompatibility complex (MHC)
What proteins participate in the co-presentation of processed peptide antigens to T cells, thereby facilitating the essential distinction of “self” from “non-self”?
human leukocyte antigens (HLAs)
All somatic cells express MHC class I, whereas only the specialized APCs can express what?
MHC class II
Granulocytes are the most common WBC. Which WBC is the most abundant?
neutrophils
_____ contain very dark blue or purple granules when stained with either Giemsa or Wright stain:
basophils
What kills bacteria that neutrophils ingest via endocytosis or phagocytosis?
- myeloperoxidase
- nicotinamide adenine dinucleotide phosphate (NADPH) oxidase
_____ are the smallest formed elements in the blood:
platelets
What are the types of single gene disorders?
Autosomal dominant, autosomal recessive, and x linked
What are some autosomal recessive disorders?
CF, PKU, sickle cell disease, etc.
What is an example of a complement protein that can opsonize?
C3b
What is an example of a complement protein that attracts leukocytes?
C5a
What happens if acute phase proteins don’t go away?
It will cause high levels of inflammation
Ex: RA
What is function of acute phase proteins?
Liver proteins that act as opsonins and that enhance the inflammatory response
Function of chemotaxins?
Molecules that attract phagocytes to a site of infection
