Handorf 1 and 2

Cellular Response, Basic inflammatory response, Tissue Injury and Repair

Notes up on blackboard.
Suggested readings over next 3 lectures are on slide 2. He recommennds Majno Cells, Tissues and Diseases to look at pathological evaluation of disease at cellular and subcellular level. Could use it in career.
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Objectives for today:
We will define a lot of words and give examples today. What goes wrong with cells?
Pathology is the study of diseased cells and tissues.
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Virchow developed concept that cells can be related to diseases. Cells can cause disease states. Cellular dysfunction results in disease. Can study disease in organs (gross), tissues (histopathology or surgical pathology), cell (cytopathology), or molecular (molecular pathology). We are in age of molecular pathology now.
7 Review of Cell Organelles and Functions
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Normal cell lives in homeostasis in health. Under stress, increased demand, or noxious or injurious stimuli, cell must adapt. If the noxious stimulus or injury is too much, cell undergoes injury or death.
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Reversible cell injury- some noxious stimuli damage can be reversed. Irreversible- cannot. Some small doses reversible, larger doses irrreversible. Where do we see changes under microscope?
Cell function decreases rapidly in reversible cell injury, but we can’t see it under microscope. Need special techniques. Most cases can’t see when cell has died with routine staining. Longer duration of injury is necessary for ultrastructural change. ER starts to swell and nucleus starts to disintegrate. Can see change to cells before you see gross morph change in organ or tissue.
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Characteristics of cell undergoing noxious stimuli not leading to death: blebbing of cell membrane, ER swelling, and chromatin clumping. These conditions can be reversed in recovery phase. Cell cannot recover if nucleus disintegrates and lysosomes rupture. Mitochondria and ER swell beyond reversible condition and cell loses ribosomes. nucleus fragments and cell dies by necrosis.
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Definitions mentioned before:
Good cell to start understanding pathological change is myocyte. Slide shows myocyte and coronal section of heart. Certain stimuli like hypertension cause left ventricle to thicken abnormally. Hypertrophies or gets bigger. See thickened left ventricle.
Cell reversibly injured would not see change. Cell goes on and dies- see coagulative necrosis in myocardial infarct.
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point of irreversibility- When has so much damage occurred that cell will die? Different cells have different points. Different cells in same family have different chars due to different internal characteristics. Apoptosis is programmed cell death- may have reversible stage or not.
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Oxygen deprivation- most organisms require oxygen for respiratory metabolism, so oxygen deprivation is bad.
Physical agents- difference between drug and poison is dose.
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ex oxygen deprivation
anoxia- complete lack of oxygen
hypoxia- diminished oxygen availability. People get these mixed up.
Ischemia- decreased blood flow. Blood carries oxygen, can get hypoxia or anoxia, but not same thing. Can have hypoxia without ischemia, as in carbon monoxide poisoning or drowning.
Infarction- process of massive cell death due to lack of oxygen availability. Infarct happens after process of infarction has occurred. Refer back to picture of heart. Heart attack is an infarct, not an infarction. The “-tion” is a process.
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Morphology of Necrosis
Terms derived prior to Virchow from gross observation
Coagulative necrosis has nothing to do w under microscope. Look grossly.
Fat different.
Caseous- looks like cheese
Fibrinoid loooks like fiber.
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Aorta from 3 people opened up to see lumen.
Bottom- beginning of plaques- in iliac artery. Plaque is building. Could see this in 18-25 yr old American.
Middle- significant athrosclerosis with plaques that can break.Top- they ulcerate and bleed into plaques.
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How it kills in coronary artery. Plaque itself occludes in angina upon exercise. What kills is plaque ruptures, fills with blood, closes lumen, leads to hypoxia and necrosis.
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septal wall showing coagulative necrosis. Red-brown muscle- yellow area is infarct with inflamed cells and histiocytes. Red rim more capillaries- growth factors released due to hypoxia. Increased oxygen stress factors are released to cause capillary growth to bring blood in to enhance repair. Unfortunately repair is not very good.
20 Under microscope how infarct looks in myocardial muscle. Looks normal. 4-12 hours after infarct cell does not change all that much.Right-PMNs come in at 24 hrs. Fibers are shrunken.
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Kidney tissue infarct
Coagulative necrosis- right shows liquefactive necrosis in an abscess in kidney
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apoptosis
cell death from inside out. Necrosis is due to outside influence inward. Apoptosis is not always genetically programmed, but because disease state causes cell to kill self.
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skin disease
squamous cells with dead cell in middle on left. Right- viral hepatitis. Can you tell apoptotic change from necrosis under microscope? Yes. You see individual dead cells within normal field. Also cell death from outside creates inflammatory response. Apoptosis does not. Some apoptosis is not individual cells.
Example: In development, cells die between fingers or you would have webbed ones. Whole field dies. Generally apoptosis happens one cell at a time.
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Robbins diagram of apoptosis.
Apoptosis- earliest changes are in nucleus, which fragments early, loss cell control, cell death.
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Cellular adaptations to injury:
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Atrophy- it shrinks or it may physiologically shrink. Cells need workload, or they atrophy.
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Brain
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Alzheimer’s brain- looks like sulci have widened. Have not. Gyri have shrunk.
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Hypertrophy- increase in size of cell due to increased demand or hormonal stimuli
Not more cells. Cells you have get bigger or contain more stuff.
Ex- working out, uterus in pregnancy
Pathologic- heart in systemic hypertension
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Gravid vs normal uterus on left.
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Hyperplasia- increase in number of cells.
Physiologically normal: breast in lactation. More ductal units develop
Pathological: endometrial hyperplasia, or benign hyperplasia of prostate- more glands and stroma
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left normal prostate. Right- hyperplasia. BPH (benign prostate hypertrophy( is really hyperplasia, but is called hypertrophy.
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metaplasia- conversion of one differentiated cell type to another differentiated cell type. In each example, focus of metaplasia provides fertile ground for malignancy to develop. Metaplasia is not cancer, but is one step in process of developing neoplasia.
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squamocolumnar junction of esophagus and stomach- see some columnar metaplasia

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dysplasia-see slide.
Considered preneoplastic (before neoplasia)- cells disorganized, begin to lose polarity.
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cervical dysplasia
Dysplasia does not always lead to cancer. Do not need metaplasia to develop neoplasia. There is a continuum in many cases, though.
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pigments and accumulations
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Iron accumulates in liver in hemachromatosis. Left- H and E, see brown granular flecks. Right- special stain clled Prussian Blue to stain iron blue. Liver used as example.
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lipofuschin in cardiac muscle in poles of nuclei. Fine granular pigment. Right under TEM- see black granular pigment at poles. This is “wear and tear” pigment- degraded lipopolysaccharides. No consequence in disease.
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Hepatocyte with globular spaces with nucleus to side. Fat accumulates in tissue. The arrow is alcoholic hyaline.
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cholesterol accumulation is not in itself a bad thing. This is gall bladder with cholesterol in submucosa. Get foamy macrophages with floccular fine cholesterol. No disease state, but related to cholecystitis. In plaque in wall of artery, would make wall friable and rip.
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cholesterol in aortas again.
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Ca deposition –Tissues calcify after cell death because acidic cell products cause precipitation of Ca. Islands of cancer cells in breast cancer- in center cells die. In mammogram calcifications show up- certain patterns show it is malignant.
48 calcification of the aortic ring.
Basic Inflammatory Response 1/11/06
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Objective for today.
Do not memorize the whole array of processes in middle. Understand there are many steps that we understand at cellular level in basic inflammatory response.
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We emphasize protective response b/c it does not look rotective sometimes. It begins in response to injury or infection, but becomes injurious. Bring PMN into site of infection with proteases, it unloads and there is innocent bystander damage.
Inflammatory is acute(after ijry) or chronic (long term)
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Think of inflammatory response as a play with stage, script, actors. Stage is body, script is way things work, list on slide is actors.
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Cartoons of actors. Primary in acute is PMN. Circular white blood cells with complex multilobe nuclei and granules of enzymes and macromolecules. Lymphocyte is key in chronic inflammatory response. PMNs diminish and lymphocytes increase. In tissue, things across bottom of slide are part of extracellular matrix.
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Morphology of a PMN
Dark area is multiplobed nucleus. Granules are hard to see in wright-giemsa stain. Don’t expect to see granules in cytoplasm
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eosinophils and basophils in subacute inflammatory response- produce histamine and antihistamine. Right- eosinophil. Nucleus with no (most common),2,3 lobules. Granules easy to see. They fill cytoplasm and look orange.
Left- basophils bluer.
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Lymphocytes and monocytes. Close morphologically. Lymphocyte on left tends to have large nucleus and little cytoplasm. Monocyte on right has gyroform (brainlike ) nucleus and some granules in cytoplasm.
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Plasma cells- producers of immunoglobulins. Characteristic appearance. Elliptical shape. Nucleus at one pole of long axis of ellipse. Cytoplasm is hazy blue-gray and clearing next to nucleus is hof (where Golgi apparatus is that packages immnoglobulins).
Nuclei are clock-face or wagon-wheel chromatin. He has never seen that. Chromatin is clumped with areas of clearing. Nromal ones all look alike.
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Macrophage(left) and Mast cell(right)
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Acute vs. Chronic- understand this slide.
Some viral inflammation goes immediately to chronic. Sometimes in injury of long duration these processes work togther.
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Vasodilation is 1st part inflammatory response. Vascular changes-Redness and warmth come from vascular dilation. Edema is swelling. Fenestrations form in swelling tissue.
Leukocytes travel out of vessel walls into surrounding tissues.
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Right after injury, very first thing that happens is vasoconstriction. Not part of inflammatory response. Release from the vasoconstriction as the muscles run out of ATP starts the vasodilation and bleeding. Increased vascular permeability: swelling in medicine is edema. Transudates are cell-poor material leaking into extracellular spaces. Exudates contain white blood cells.
Red cells are left behind in vessels and get concentrated because fluid can leak out. Blood viscosity increases.
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exudate vs. transudate
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Mechanisms of the acute inflammatory response
Increased vascular permeability is immediate and transient. Endothelial cells contract and leave fenestrations for fluid to leave.
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Some stimuli reorganize the cytoskeleton of endothelial cells, a response which is reversible in venules and capillaries (under stimulus of hypoxia, for example).
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Can have direct endothelial injury from burns or chemical injury.
Endothelial death- not reversible., but reparable.
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leukocyte-dependent injury- recruit lots of PMNS- direct cell injury in venules and common in pulmonary capillaries. Irreversible endothelial damage.
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Transcytosis- fluids and cells migrate through endothelial cell in venules without damaging much.
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Neutrophil again- know facts. They are phagocytic, but also contain lysosomes for carrying chemicals to site to digest dead tissue so histiocytes can clean up garbage.
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Destruction and digestion by phagocytosis.
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Neutrophils go through these processes. Chemotaxis- drawn to site of injury. Blood vessel and other players are involved.
28 Selectins and integrins mediate migration. At site of injury, increased viscosity creates some passive pushing of white blood cells to periphery. They are directed to endothelium by selectins, which chemically attach to white blood cells and cause them to slow down and attach to walls of vessel. 1st process after attachment is rolling. Eventually leukocyte is physical attachment to endothelial wall, then moves through and into area of injury.
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Sequence of events.
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P selectin is activated through appropriate stimulation by histamine and thrombin. Cell is platelet on slide. P selectin redistributed to surface of cell.
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E selectin upregulates and allows for adhesion of neutrophils
33 PMN
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Attachment and release results in rolling until cell slows down and stops.
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Adhesion and cell migration
38 Cell adheres and prepares for transmigration
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transmigration.
PECAM-1 is expressed as CD31, so we can stain to see work immunohistochemically.
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Injured myocardium. Lots of PMNs on left. After 2 ½ or 3 days, you see monocytes and macrophages on cleanup.
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Chemical signals through gradient. Whole orchestra of molecules creates gradient.
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Chemotaxis is complicated. IP3- pseudopods are assembles for chemotaxis in PMNs. Begins with high Ca. Crawls on little feet (pseudopods).
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Oxidative burst- bacteria that have been phagocytosed are dispatched.
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Steps in phagocytosis. Opsonins are nonhomogeneous, but they allow a foreign substance to be attractive to white blood cells. Phagolysosome forms and invader dies.
Oxidative burst important for killling. Form reactive oxygen metabolites. MPO is myeloperoxidase. Acid hydrolases are also in granules.
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Mediators of inflammation
Mast cells and basophils are same cell in different location- mast cell in tissue, basophils in blood.
Physical action – histamine results in allergic response when mast cells degranulate.
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Neuropeptides important for transmitting pain signals. Normally regulate vascular tone.
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3 systems involved with plasma proteases. Linked by factor 12 from liver.
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How proteins link up. Collagen and basement membrane are exposed in injury.
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Clotting system’s involvement in inflammatory response, not what it does stopping bleeding. Clotting proteins and macromolecules contribute to other things as well (vascular permeability, chemotaxis, adhesion)
Do not memorize all these pathways. If you work with them, they will become something you know.
Complement system mediates inflammatory response.
70 summary plasma proteases
memorize this slide.
76 know definitions on this slide
82 Functional loss is often from scarring from protease release.
83 Lists macromolecules in granules. Do not memorize.
85 Chronic inflammation- lots of tissue destruction and loss of function.
90 Granulomatous inflammation- distinctive chronic subpattern. Cell leading to granuloma formation is epitheloid macrophage. Respond to certain microbes, but microbe is not fully dealt with. No chemical or other ability to dispose of it. Reach stalemate. Microorganism lives inside epithelioid macrophage. Same thing happens with foreign material like suture. Giant cells fuse to form granuloma.
91 shows fused epithelioid macrophages and necrotic region in middle of granuloma. Sequesters organism, but does not get rid of it.
92 Epithelioid macrophage at lower left
94 serous inflammation is blister
96fibrinous inflammation: Fibrinogen efflluxes from vessels- fibrin gets laid down and is durable molecule. Fibrin laid down on outside of heart
97 suppurative inflammation. Words and definitions.
99 ruptured appendix
100 stomach ulcer
101 close up picture. Sides- normal mucosa
103 ESR is lab test marker of inflammation because of change in balance of plasma proteins. Erythrocytes fall faster in column of serum.
Tomorrow start at 9:00.