MOD Exam 1, Chp 1-4 Flashcards
[FA] A pt undergoes thrombolysis for acute limb ischemia. What type of free radical injury is of greatest concern? What specific radical is formed?
What 4 things happen in this?
Reperfusion injury (eg, from superoxide formation)
Increase Ca
Increae ROS
incresae neutrophils
increase Complement
[FA] What causes the yellow-brown color of the macrophages seen on autopsy of an elderly woman?
autophagocytosis (this is lipofuscin)
[FA] Name some tissues where lipofuscin is commonly found on autopsy.
All tissues, but especially the heart, colon, liver, kidneys, and eyes
[FA] What is atrophy and what causes it? What’s the mechanism?
(caused by disuse, denervation, hypoperfusion, loss of hormones, poor nutrition)
autophagy and ubiquitin-proteasome pathway
[FA] Bx of a blood vessel in a 60 yo woman w/headaches and vision loss shows immunoreactive components. Type of hypersensitivity reaction?
Type III hypersensitivity reaction. This is fibrinoid necrosis. Seen in hypertensive emergency, polyarteritis nodosa, preeclampsia
[FA] 36 yo pt w/hypercalcemia presents w/hypervitaminosis D. Where does one tend to see the deposits, and what is the mechanism of deposition?
Deposits usually occur in interstitial tissues of kidney, lungs, and gastric mucosa (tissues losing acid ↑ pH, favoring Ca2+ deposition)
[FA] Free radicals damage cells by which 3 main mechanisms?
Membrane lipid peroxidation, protein modification, and DNA breakage
[FA} Free radical damage by carbon tetrachloride causes what pathologic change in the human body?
Fatty change in the liver (CCl4 is converted into CCl3 free radical by cytochrome P-450, leading to ↓ apolipoprotein synthesis)
[FA] Coagulative necrosis occurs after ischemia/infarction except in stroke. What is the key difference as compared w/liquefactive necrosis
Coagulative necrosis, enzymatic degradation due to injury blocks proteolysis;
liquefactive, enzymes released from neutrophils digest tissue
What is the mechanism for chromatin clumping? Is this reversible?
Mitochondria damage –>
Decrease ATPase –> anaerobic oxphos – lactic acid –> acidic pH –> hcromatin clumping
Yes reversible
What does the mitochondrial permeability transition pore let in?
H+ leaks, no gradient for oxphos
- formation of ROS
- Cytochorme C release
In cellular damage where does the excess Calcium come from?
Smooth ER first, then influx across membrane with the MPTP
What are myelin figures?
Evidence of membrane damage, seen on histo.
Large phospholipid coagulations
DNA methylation results in what?
Transcription silencing
What does major basic protein do?
It is contained in granules of eosinophils and is highly toxic to parasites
What cells contains FcERI receptors? What does this bind to?
Mast cells, binds to Fc portion of IgE
What does chromatin do?
linkers for nucleosome
In order to track DMII and HTN, what DNA variations can you look for?
SNPs in neutral positions, causes a linkage disequilibrium
Fxn of peroxisomes?
Fatty acid metabolism
Fxn of phosphatidyliniositol?
- Phosphorylated so IC proteins can bind. Hydrolyzed to generate intracellular signal;
Glycophosphatidylinisisotl - allows extracellular proteins to bind
- Associated with Caveolae mediated endocytosis as well
What does phosphatidylserine have to do with clotting?
- Cofactor with a negative charge
- pulls Ca and Na into the cell,
- serving as a nucleation site
- platelets to change shape
How do proteins get into the membrane?
They must be attached to a lipid on the cytosolic side
Such as prenyl - cholesterol; or a fatty acid.
What is potocytosis?
Pinocytosis?
Receptor-mediated?
Which allows large macromolecule ssuch as LDL to enter?
Potocytosis: Caveolae associated. cAMP
Pinocytosis:
- Clathrin
- LDL large guys
Receptor-Mediated:
Fuse with acidic lysosome
What causes familial hypercholesterolemia?
LDL receptor defects
What type of cytoskeletal filament is vimentin? What is it’s fxn?
Mesenchymal cells
intermediate filament
Where are clathrins? Cadherins? Catenin? Claudin? Connexins?
Clathrins - Pinocytosis
Cadherins - desmosomes
catenin & claudin - types of occluding jxn fibers
Connexins: Gap jxns
how does a cell attach to the ECM?
how does a cell attach to another cell?
Spot desmosomes use what protein?
hemidesmosome, integrins and focal adhesion complexes.
E-cadherins (belt desmosome) & spot
Spot desmosomes: s desmogleins/desmocollins
How are ubiquitins put on proteins?
E1,E2,E3 ligases
How are lysosomes tagged for degradation?
LC3 and M6P
What is the fxn of SHH in cell surface triggers?
Proteolysis cascade
What is the Receptor Tyrosine Kinase cascade?
What can bind to RTK?
Growth factor binds –> activate RAS –>
PI3K –> Akt –> mTOR
and RAF –> MAPK –> Activates MYC protein –> Cell Cycle Progression
Can bind: insulin, PDGF and EGF (platelet derived GF and epidermal GF)
What growth factor is associated with ERBB2 and breast cancer?
Where is the source and what is the fxn?
Epidermal Growth Factor EGF.
Source: macrophages, keratinocytes, salivary glands
Fxn: Produce keratinocytes and fibroblasts, form granulation tissue.
What growth factors aid in wound healing (make collagen)?
EGF - epidermal
PDGF - platelet derived
FGF - fibroblasts
TGFb
What growth factors aid in hepatocyte regeneration?
What is the source of these guys?
TGFalpha
HGF
Source:
TGFalpha: macrophages, keratinocytes,
HGF: Fibroblasts, liver stroma
There is a growth factor that is induced by hypoxia, relased by mesenchymal cells, and causes angiogenesis. What are the 3 fxns of these factors and what are they?
Vascular Endothelial GF
General fxn: proliferation of endothelial and incresd vascular permeability
- Ab against VEGF used for renal and colon cancers
- Anti-VEGF treats we macular degeneration as well (blood leaks into macula)
- Increase VEGFR causes preeclampsia
PDGF have a few types. which ones are always active?
What is it’s fxn?
AA, AB, BB active
CC, DD need activated
PDGF recruits smooth muscle cells
MET is a receptor that is overexpressed in many tumors. WHat specific growth factor does it increase?
HGF (scatter factor)
What do smads have to do with anything?
TGFb activates these when they bind to serine and threonine I and II. increases transcription
What is basement membrane made out of?
interstitial matrix ECM?
BM: overlying epithelium and underlying mesenchhymal cells, and IV collagen
Intersitital matrix: fibroblasts
What is lysyl oxidase?
Dependent on Vitamin C to make collagen.
Ascorbic acid deficient pts will have a hard time with wound healing and bleeds easy.
Ehler Danlos Syndrome
& osteogenesis imperfecta (2 yo with fractures)
What are the nonfibrillar collagens and their fxns?
VIII: anchor fibrils to BM
IV - planar basement membranes
IX - FACITS in cartilage
What is elastin composed of?
Fibrillin
What is the purpose of water hydrated gels?
Proteoglycans Resist compressive forces in the joints
Hyaluronan attach to proteoglycans.
These are both negative and pull cation and water
What are the adhesive glycoproteins and their fxns?
Fibronectin:
- Provides scaffolding in wound healing
Laminin: connect ECm to IV collagen
Integrins: Firm adhesion from epithelium to leukocytes
What Cyclins and CDK phosphorylate retinoblastoma?
What removes the G2-M block?
What activates S phase?
D/CDK4
D/CDK6
E/CDK2
B/CKD1
S phase:
- A CDK2, A CDK1
Which stem cell is embryogenic?
PLURIPOTENT from inner cell mas (think: pulp from blastocyst)
Adults is Multipotent
and all is totipotent
Myositis ossificans is an example of what tissue adaptation?
formation of bone within muscle after trauma = metaplasia
Growth of uterus during pregnancy is caused by what cellular adaptation?
hypertrophy
Which cellular adaptation has a strong association with hormones? Give examples of physiologic?
hyperplasia
- Female breast during puberty
- Liver regeneration
- Bone marrow, EPO = 8x increase in RBC progenitors
What is the mechanism of hypertrophy? What transcription factors are used and what signaling pathway?
What can we do to prevent hypertrophy? Which isoform is stronger?
What protein is upregulated in associatino with hypertrophy?
Transcription factors: GATA NFAT, MEF2
Signaling Pathway: PI3K/AKT (physiologic)
GPCR for pathologic
- inhibit transcription factors
- isoform b is stronger
ANF
–> expressed in heart in fetal heart
What pathway is used in atrophy?
Ubiquitin-proteasome pathway
and autophagy
Results in lipofuscin granules
What are lipofuscin granules and when would you see htem?
What is hemosiderin?
When a cell is atrophy-ing. mainly when lipid peroxidation is happening bc it’s a product of ROS/autophagy
Hemosiderin - lots of RBC destruction bc it’s iron
Vitamin A deficiency can cause what?
Metaplasia bc it alters gene transcription
A histological slide is given. You see cells that are very pink, myelin figures, calcification, with no nucleus. What is happening to the cells?
Necrosis
How can you increase the success of a stem cell transplant?
Reprogram somatic cells to become pluripotent with MYC and SOC2 genes and by using Cas9 and CrISPER to alter DNA sequences
myc has to do with oncogene
You see a brain slide that is very pink, had myelin figures and calcification. There are cystic spaces and cavitation. What stage of necrosis and what type of necrosis are we?
Liquefactive and late stage
Macrophages walling off a bacteria usually involves what bacteria and what type of necrosis?
Caseous and TB/fungi
Called a granuloma
Preeclampsia is involved with which necrosis? What is the mechanism?
What other conditions are associated?
Fibrinoid.
Type III hypersensitivity bc forms immune complexes with fibrin
HTN emergency and immune rxns in vessels
What 2 necrosis is associated with the pancreas?
Peripancreatic fat- fat.
Pancreatic parenchyma - liquefactive necrosis