misc first 10 Robbins chapters Flashcards
List some AD inherited syndromes
- Huntington disease - Marfan syndrome - Familial hypercholesterolemia - Achondroplasia
What does serum transferrin measure?
- Iron absorption
- transferrin saturation=serum iron x 100/total iron binding capacity
What type of organisms are Nocardia species?
- Gram positive bacteria growing in bead-like chains - They cause skin, CNS, respiratory infections in immunocompromised patients
DIC depletes all factors except:
- Fibrin split products
Which inheritable genetic condition exhibits anticipation?
- Huntington disease
JAK2 mutations are associated with which condition?
- Polycythemia vera 95% are associated with JAK2 mutations
Name an anti-apoptotic protein
- BCL2, is anti-apoptotic and up-regulated in malignancies when compared to non-malignant conditions
- Eg. follicular lymphoma vs reactive lymphoid follicle
In what condition would you expect to see cardiac rhabdomyomas in children?
- Tuberous sclerosus, where cardiac rhabdomyomas are seen in 50% of neonates
Which cellular process is associated with cytochrome C release from the mitochondria?
- Intrinsic pathway apoptosis
What are the conditions associated with trisomies 13, 18, 21?
13=Patau
18=Edward
21=Down syndrome
Name a disease associated to HLA-DR3
- diabetes
Which disease is associated with an 8:14 translocation?
- Burkitt lymphoma
- c-myc/IGH translocation
Name 3 functions of p53
- Induces cell cycle arrest
- induces apoptosis
- upregulates genes involved in DNA repair from radiation
What is the translocation involved in synovial sarcoma?
- t (X;18), SYT-SSX
What are kimmelstein wilson bodies and what disease are they associated with?
- Pink hyaline nodules forming in glomerular capilaries, seen in diabetes
What is the IF staining pattern associated with Lupus?
Full house: IgG, IgA, IgM and complement
Name a proto-oncogene
KRAS
What virus is implicated in Kaposi sarcoma
HHV8
Name a condition associated with abnormal imprinting
- Prader-Willi, associated with 15q deletion in paternally derived chromosome
- Angelman syndrome associated with 15q deletion in maternally derived chromosome
Describe the effects of whole body irradiation by sievert ranges
0-1 none
1-2 lymphocyte damage, moderate granulocytopenia
2-10 sv: bone marrow destruction (leucopenia infections, n/v, fatigue), skin burns and rash with mucosal desquamation
10-20sv: damage to mucosal surfaces within small bowel; severe diarrahea, fatigue, NV, permanent sterility
>50 sv: damage to brain, coma and convulsions
What is the function of the Langerhans cell? What are the ultrastructural features?
- functions in antigen presenting in the skin
- BIrbeck granules are present in the cytoplam
What is the Lyon law?
- Lyon law refers to the random and fixed inactivation of one X chromosome in mammalian cells at an early stage of embryogenesis, leading to mosaicism of paternal and maternal X chromosomes in females
What are functions of mast cells?
- Degranulation and release of allergic mediators from granules in response to allergens (immediate hypersensitivity)
- Release of eicosanoids (thromboxane, PGD2, leukotrienes) for late phase allergic response
Describe the types of prostaglandins and their functions
- PGI2: promotes vasodilation, inhibits platelet aggregtion
- PGE2: decreases gastric acid, increases gastric mucin, promotes vasodilation and GI smooth muscle relaxation
- PGD2: promotes vasodilation, increased vascular permeability
Describe the structure of an IgG molecule
- Y-shaped structure with variable domain regions at the top of the Y arms and constant (FC) region at the base
- 2 heavy chains and 2 light chains linked by disulfide bonds stabilize the structure
What is the most likely organism implicated in lung fungus balls?
- Aspergillosis from mold Aspergillus fumigatus
What causes chronic granulomatous disease?
- Cause: genetic defect in the phagocyte oxidase enzyme in neutrophils (NADPH oxidase), defect is x-linked or AR
- NADPH required for respiratory burst in neutrophils activated by bacteria; generation of reactive oxygen species requires multiprotein NADPH oxidase complex that reduces oxygen to a superoxide anion and is able to form hydrogen peroxide. Hydrogen peroxide is further broken down into hypocholrite/halides to kill bacteria.
- Reaction takes place in phagocytic vacuoles
- Deficiency leaves pts prone to bacterial infections
Erythroblastosis is which type of hypersensitivity reaction?
- Antibody mediated (type 2) hypersensitivity rxn
- IgM/IgG binds to RBCs and triggers phagocytosis/lysis using membrane attack complex
Describe some types of brown pigmentation in tissue
- BIle (green-brown): seen in bile canaliculi, intrahepatocytes. Stains with Hall’s bile stain.
- Copper (yellow-brown): periportal hepatocytes, stains with orcein/rhodanine.
- Iron (golden brown, refractile): in periportal hepatocytes, Kuppfer cells, iron overload. Perls Prussian blue.
- Lipofuscin (brown): in centrolobular hepatocytes, maybe in Kuppfer cells. Acid fast stain + (FITE)
- Melanin (black/brown, non refractile): melanoma, nevi, melanocytes.
What are some burn classifications and how do you estimate severity?
- Can use 1st, 2nd, 3rd degree or superficial, partial thickness, full thickness
- Superficial is epidermis only, erythema
- Partial thickenss is epidermis/dermis, blistering
- Full thickness is down to fascia/fat/muscle, painless, black
- Estimating severity: rule of 9s (each arm=9%, each side of torso 18%, each leg 18%, head and neck 9%)
- A burn requiring burn unit would be facial, perineal, cirumferential extremity burns, burns crossing joints, inhalational, any partial thickness >10% TBSA, any full thickness
What is the role of ATP in diffuse axonal injury?
- Diffuse axonal injury is due to shear forces from rapid acceleration /deceleration leading to axonal disruption or separation in the brain stem, corpus callosum cerebral hemispheres, cerebral cortex, cerebral peduncles or basal ganglia
- Is a biochemical cascade; initiating factor is disruption of microtubule skeleton. Axonal transport continues to the point of rupture where amyloid precursor protein is carried and accumulates via ATP-dependant proteins; this leads to retraction balls caused by axonal swellings
- Further changes include opening of sodium channels, loss of calcium gradient, activation of phospholipases/caspases
What is Reye syndrome?
- A sudden, potentially fatal disease of brain (encephalopathy) with degeneration of the liver
- Occurs in children, 4-12 yrs
- Post-viral (varicella, influenza)
- associated with aspirin
- presents with vomiting, lethargy, progressive neurologic dysfunction
- histology: acute non-inflammatory encephalopathy and acute fatty liver changes
Define angiogenesis
- Angiogenesis: the physiologic process of developing new blood vessels from pre-existing vessels that allows essential physiologic processes to take place: wound healing, revascularization after trauma, menstruation, granulation tissue
- Pathologic angiogenesis occurs with tumor growth, diabetic retinopathy, chronic inflammation
- Vasculogenesis is growth of new vessels from circulating stem cells during embryonic development
List 5 angiogenic growth factors
- Vascular endothelial growth factor (VEGF)
- Platelet derived growth factor (PDGF)
- Transforming growth factor B (TGF-B)
- Fibroblast growth factor (FGF)
- Angiopoeitin 1/2
How does VEGF function?
- VEGF is most important angiogenic factor
- Binds to VEGF receptor, promotes the release of endothelial precursor cells from bone marrow
- Stimulates endothelial cells to migrate and proliferate to new vessels from existing ones
- Induced by hypoxia, TGF-B released from wounds, PDGF from platelets, TGF-a from inflammation
At what point after an injury does a wound reach 10%, 50% and 80% of its preinjury tensile strength?
1 week=10%
1 month=50%
3 months=80%
Describe the cells and factors involved in wound healing
Phase 1: homeostasis. Hours 0-24. Clot formation. Involves platelets, neutrophils. Factors: fibrin, growth factors, cytokines, clotting cascade.
Phase 2: inflammatory phase. 3-7 days. Formation of granulation tissue, macrophages remove bacteria and debris. Cells: fibroblasts, macrophages, endothelial stem cells. Factors: VEGF
Phase 3: proliferative phase. 1-3 weeks. Cells: fibroblasts deposit collagen, myofibroblasts contract wound, epithelial cells re-epithelialize. Factors: type 3 collagens, laminin, FGF, TGFB, chemokines
Phase 4: remodelling (3 weeks-months). Scar tissue formation at 4 weeks, collagen cross linking, replacement of type 3 collagen with type 1 collagen. Cells: fibroblasts, macrophages. Factors: MMPs, inhibitors of MMPS.
Describe the sequence of events in healing by primary intention
- Occurs in small, clean incisions where edges line up
- Standard 4 phases of wound healing: clot, inflammation, proliferation, maturaiton
- either small lacerations/surgical wound, heals with minimal scarring
Describe the sequence of events in healing by secondary intention
- Larger wounds heal with more granulation tissue, scar, wound remodeling and contraction
- Broader scar formation, slow to heald if infected, requires wound care to prevent infection
What basic processes are involved in wound repair by connective tissue deposition?
- Inflammation, angiogenesis, migration/fibroblast proliferation, scar formation, connective tissue remodelling
Name 4 local factors and 4 systemic factors retarding wound healing
Local: infection, mechanical (early motion), foreign bodies, size/location of wound
Systemic: nutrition (protein deficiency, vitamin C deficiency), metabolic status (DM), circulatory status, glucocorticoids
List 2 examples of abnormal wound healing
- Keloid scar
- Wound dehiscence
List vitamins affected by pancreatic insufficiency
ADEK (fat soluble)
List fat soluble vitamins, their physiologic functions, and diseases resulting from deficiencies
A: vision, embryogenesis, epithelium formation, infection resistance. Deficiency: night blindness, corneal dryness, infections, squamous metaplasia
D: calcium absorption from intestines, bone mineralization. Deficiency: bone defects, osteoporosis
E: antioxidant. Deficiency: spinocerebellar degeneration, immune response, retinopathies
K: cofactor for factors II, VII, IX, X in coagulation cascade. Deficiency: bleeding
List the fat insoluble vitamins, physiologic function and diseases from deficiency.
B1 (thiamine): coenzyme in decarboxylation. Wernicke-Korsakoff.
B2 (riboflavin): enzyme cofactor. Angular chelitis, stomatitis…etc.
B3 (niacin): NADH/NADPH formation. Pellagra: dermatitis/dementia/diarrhea
B6 (pyroxidine): Synthesis of serotonin/dopamine/norepi/epi. Peripheral neuropathy, depression, dermatitis
B12 (cobalamin): DNA/folate syntehsis. Megaloblastic anemai, posterior lateral spinal cord degeneration.
C: collagen hydroxylation. Scurvy (bleeding mucous membranes)
Folate: DNA synthesis. Neural tube defects, megaloblastic anemia.
Panthothenic acid: needed for coenzyme A. Numbness/burning in feet.
List the common causes of vitamin B12 deficiency
- Autoimmune gastritis with pernicious anemia
- Inadequate vitamin B12 intake
- Terminal ileum damage/resection
- Crohn disease
- Intestinal bacterial overgrowt
- Fish tapeworm infection
List the pathologic features of vitamin B12 deficiency
- peripheral neuropathy: dgeneration of dorso-lateral spinal columns with ataxia, weakness
- Macrocytic anemia: leukopenia with macro polymorphs, giant megakaryocytes
- Atrophy and intestinal metaplasia of stomach (pernicious anemia)
Describe the synthesis of vitamin D
- 7-dehydrocholesterol reacts with UVB in skin to form vitamin D3
- D3 is processed in liver by 25-hydroxylase to 25-OH-D3
- 25-OH-D3 processed in kidney by 1-alpha-hydroxylase to 1,25 dyhydroxy vitamin D
What are the biologic effects of vitamin D?
- Increases calcium and phosphate absorption in gut
- Induces bone mineralization
- suppresses PTH secretion
What part of the complement system is responsible for lysing RBCs?
- RBC lysis requires membrane attack complex formation (MAC) formed by classical pathway complement proteins
- Classical pathway: IgM/IgG bind antigen and C1, C3 binds and activates C3 convertase=C3a and C3b. C3a forms C5 convertase=C5a. This leads to membrane attack complex formed of C6 and C9.
- Alternate pathway: triggered by LPS on bacteria
- Lectin pathway: binds sugars on bacteria
What type of toxicity does oxygen cause to cells?
- Oxidative damage. Excess oxygen causes formation of free-radicals and reactive oxygen species, which can lead to direct damage to cell membranes, nuclear DNA, cellular organelles
UV causes what type of DNA damage?
- UVB: cross-links between adjacent cytosine/thymidine forming pyrimidine dimers
- UVA: free radical formation cuases indirect DNA damage or breaks
List 5 types of DNA damage
- Oxidation of base pairs and DNA strand breaks from ROS
- alkylation of bases (methylation)
- Hydrolysis, including deamination, depurination, depyrimidation
- Adduct formation (modification with benzopyrene rings)
- DNA mismatch repair
List 3 biochemical mechanisms responsible for cell damage
- ATP depletion (reults in loss of function of NA/K pumps)
- pH drop from lactic acid accumulation and anerobic metabolism, denaturation of enzymes
- Ca2+ entry into cells with activation of proteases, phospholipases, endonucleases
- Osmotic changes (cell rupture)
- Detachment of ribosomes from ER with decreased protein synthesis
Define apoptosis and describe pathogenesis
- Apoptosis: programmed cell death pathway, regulated by enzyme cascade, leading to DNA fragmentation, apoptotic bodies and cytoplasm degeneration
- Intrinsic pathway: release of mitochondrial proteins (cytochrome C) to activate caspase 9
pro-apoptotic: BAX, BAK
anti-apoptotic: BCL2, BCL-x, MCL1
- Extrinsic pathway: plasma membrane receptors containing FADD/death domains bind ligands and activate caspases, resulting in apoptosis (FAS ligand/FAS receptor)
- Common downstream effect is activation of executioner pathways (caspase 3,6) leading to DNAses to cleave DNA; results in fragmentation into DNA ladders of approximately 200 bp
Compare and contrast apoptosis and necrosis
Apoptosis: no inflammation in surrounding tissue, isolated cells in healthy tissue
cytology: pyknotic nuclei, condensed chromatin, chromatin fragmentation (karryorexkis), cell shrinkage, blebbing of plasma membrane, formation of apoptotic bodies
staining: cell membrane not permeable to staining agents
EM: dense nuclear crescents and apoptotic bodies
Necrosis: inflammatory reaction frequent, cells die together resulting in structural deformation
cytology: karyorrhexis, edema, chromatin fading
staining: cell membrane permeable to stains
EM: swollen mitochondria, vacuoles in cytoplasm, fragmented organelles, ruptured plasma membrane/nuclear membrane
List 4 physiologic instances where apoptosis occurs
- Programmed destruction during embryogenesis
- Involution of hormone dependant tissues (endometrium)
- Cell loss in proliferating cell populations (immature lymphocytes in thymus)
- Elimination of potentially harmful self-reactive lymphocytes
- Death of host cells (eg. neutrophils) in acute inflammatory response
List 4 pathologic instances of aoptosis and list the gene involved in regulating it.
- DNA damage (free radicals from radiation, chemotherapy, hypoxia)
- Accumulation of misfolded proteins (neurodegenerative disease, alpha-1-antitrypsin)
- Cell death in certain infections (acute hepatitis)
- Atrophy in parenchymal organs after duct obstruction (pancreas, parotid, kidney)
BCL2 is regulator for apotosis.
List functions of p53 in normal cell cycle
- p53 is guardian of the genome; thwarts neoplastic transformation by 3 mechanisms:
- activation of temporary cell cycle arrest (for DNA repair)
- induction of permanent cell cycle arrest (sensecence)
- triggers programmed cell death (apoptosis)
What is the role of p53 in carcinogenesis?
- Guardian of genome, functions at G1/S checkpoint in cell cycle
- Senses DNA damage and induces DNA repair, p53 mutation leads to DNA damage accumulation
- Indues senescence/apoptosis if damage sensed; mutation leads to immortalization via defective apoptosis
- p53 mutation leads to aneuploidy via centrosome destabilization (multipolar spindle)
What are the clinical implications of p53 mutation testing
- Confirming malignancy (in certain cases)
- Identifying cancer subtypes (i.e. triple negative breast ca)
- Suggesting mechanism of carcinogenesis (Li-Fraumeni is inherited, increased risk of sarcomas, gliomas, leukemias, carcinomas)
- May predict response to chemotherapy/radiotherapy
What methods can be used to detect p53 mutations?
- PCR assay
- Direct sequencing
- IHC
Describe the function of miR-34 with respect to p53
- p53 activates transcription of miR-34
- miR-34 is a microRNA, small RNA molecules targeteting messenger RNA for destruction. MiR-34 targets cyclins, BCL-2, myc, cyclin-dependant kinases, notch for degradation
- once these are degraded, cell goes through apoptosis/quiescence/senescence
Define cell necrosis
- Cell necrosis: morphologic changes indicative of cell death caused by progressive enzymatic degradation
- May affect groups of cells, part of structure or entire organ
Describe some pathological processes involved in cell death
- Factors external to cell: infections, hypoxia leading to irreversible cell injury
- ATP depletion, pH change, osmotic formces leading to denaturation of cell proteins/loss of membrane integrity
- Release of enzymes from lysozymes, leading to degradation
List 3 histologic types of cell necrosis and one example of each
Coagulative necrosis: infarcts (myocardial, splenic)
Liquefactive necrosis: abcess, stroke
Gangrenous necrosis: diabetic foot ulcer
Caseous necrosis: TB, histoplasma, other fungal infections
Fat necrosis: acute pancreatitis
Fibrinoid necrosis: vasculitis (leukocytoclastic, Wegeners’…)
Name 2 histologic features of reversible cell damage
- Cellular swelling
- Fatty change
List 4 vascular changes in acute inflammation
- Vasodilation
- endothelial permeability
- neutrophil recruitement
- blood flow stasis
List 4 endothelial leukocyte adhesion molecules
- L-selection (CD34)
- VCAM 1
- P and L-selectins (sialyl-lewis modified proteins)
- B2 integrins (CD18), which bind ICAM, fibrinogen, fibronectin
List 5 inflammatory mediators
- Histamine
- Serotonin
- Cytokines
- Tumor necrosis Factor
- interleukins
- chemokines
- leukotrienes
- complement factors
- nitric oxide
- ROS
List 5 gross morphologic features seen in diabetes
- Blood vessels: atherosclerosis of aorta, peripheral vascular disease with ischemic foot ulcers, renal artery stenosis, stroke, coronary artery atherosclerosis
- Kidneys: nephroscelrosis
- Eyes: retinopathy, glaucoma, cataracts
- Skin: cellulitis
- Bladder: autonomic neuropathy, dysfunctional bladder
List 5 clinical features in untreated diabetes and 4 causes of death
- Diabetic retinopathy, diabetic peripheral neuropathy, diabetic foot/amputation, diabetic nephropathy, atherosclerotic cardiovascular disease
- causes of death: stroke, MI, infection/sepsis, renal failure
What invasive fungal infection occurs in DM and in immunocompromised patients?
- Mucormycosis/zygomycosis: fungus has large, non-septate hyphae, 90 degree branching. Angioinvasive.