mkdir -p /home/daytona/workspace/anki && cat > /home/daytona/workspace/anki/cell_injury_anki.txt << 'ENDOFFILE' Cell Injury - Reversible, Irreversible, Free Radicals <b>CAUSES OF CELL INJURY</b><br><br>Hypoxia/Ischemia (most common - depletes ATP via failure of oxidative phosphorylation), Toxins (CCl4, ethanol, drugs, CO, asbestos), Infectious agents (viruses, bacteria, fungi, parasites), Immunologic reactions (autoimmune, allergic, chronic inflammation), Genetic abnormalities (chromosomal defects, point mutations, enzyme defects), Nutritional imbalances (protein-calorie deficiency, vitamin deficiency, obesity), Physical agents (trauma, radiation, extreme temperature, electric shock).<br><br><b>REVERSIBLE CELL INJURY</b><br><br>Definition: Derangement of function and morphology that cells can RECOVER from if stimulus is removed. Key mechanism: failure of ATP-dependent Na+/K+ pump leads to Na+ influx, water influx, and cellular swelling. Gross findings: pallor, increased turgor, increased organ weight. Morphologic features (light microscopy): cellular swelling (hydropic change/vacuolar degeneration - small clear vacuoles in cytoplasm from distended ER segments), fatty change (lipid vacuoles in liver and lipid-metabolizing cells), increased eosinophilia (loss of cytoplasmic RNA). Electron microscopy: (1) Plasma membrane blebbing, blunting, loss of microvilli, (2) Mitochondrial swelling with small amorphous densities, (3) Myelin figures in cytosol from phospholipids of damaged membranes, (4) ER dilation with detachment of ribosomes/polysomes, (5) Nuclear chromatin clumping.<br><br><b>IRREVERSIBLE CELL INJURY</b><br><br>Point of no return: occurs when injury persists beyond recovery threshold. Three hallmarks of irreversible injury: (1) Inability to restore mitochondrial function/oxidative phosphorylation even after removal of original insult, (2) Altered structure and loss of function of plasma membrane and intracellular membranes, (3) Loss of structural integrity of DNA and chromatin. Injury to lysosomal membranes causes enzymatic digestion of cell = necrosis. Massive calcium influx activates phospholipases, proteases, endonucleases, ATPases - destroying organelles and membranes.<br><br><b>NECROSIS - MORPHOLOGY</b><br><br>Cytoplasmic changes: increased eosinophilia (denatured proteins + loss of RNA), glassy homogeneous appearance (loss of glycogen), vacuolated moth-eaten cytoplasm (organelle digestion), discontinuities in membranes, mitochondrial dilation with large amorphous densities, myelin figures. Nuclear changes: (a) Pyknosis - nuclear shrinkage, increased basophilia, DNA condenses into dark shrunken mass, (b) Karyorrhexis - fragmentation of pyknotic nucleus, (c) Karyolysis - basophilia fades due to DNase digestion of DNA. All nuclear changes resolve in 1-2 days. Necrosis ALWAYS elicits local inflammatory reaction (unlike apoptosis).<br><br><b>PATTERNS OF NECROSIS</b><br><br>(1) Coagulative - most common, preserved architecture, firm texture, caused by ischemia (all organs except brain), protein denaturation dominates over enzymatic digestion. (2) Liquefactive - characterized by liquefaction due to enzymatic digestion dominating, seen in brain infarcts and bacterial abscesses. (3) Caseous - cheese-like friable appearance, seen in tuberculosis, enclosed by granuloma, combination of coagulative and liquefactive. (4) Fat necrosis - saponification of fat by lipases, chalky white deposits, seen in acute pancreatitis and trauma to fat. (5) Gangrenous - ischemic limb necrosis - dry (coagulative) or wet (liquefactive + bacterial) gangrene. (6) Fibrinoid - immunologically mediated vascular damage, fibrin-like pink deposits in vessel walls, seen in immune vasculitis and malignant hypertension.<br><br><b>APOPTOSIS vs NECROSIS</b><br><br>Apoptosis: regulated/programmed, caspase-mediated, cell shrinks, apoptotic bodies formed, plasma membrane intact, NO inflammation, affects single cells. Necrosis: accidental/uncontrolled, membrane disruption, cell swelling, elicits inflammation, enzymes leak out, affects groups of cells.<br><br><b>FREE RADICALS AND OXIDATIVE STRESS</b><br><br>Definition: chemical species with single unpaired electron in outer orbit - highly reactive, attack proteins, lipids, carbohydrates, nucleic acids. Chain propagation: molecules that react with free radicals are themselves converted to free radicals (autocatalytic). Reactive Oxygen Species (ROS): most important class - superoxide anion (O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH-). Oxidative stress: increased production OR decreased scavenging of ROS leads to excess free radicals.<br><br><b>GENERATION OF FREE RADICALS</b><br><br>(1) Normal metabolic processes: partial reduction of O2 during mitochondrial respiration generates O2- (1e-), H2O2 (2e-), OH- (3e-). (2) Radiant energy: UV light, x-rays hydrolyze water into OH- and H radicals. (3) Activated leukocytes (neutrophils, macrophages): NADPH oxidase complex generates rapid ROS burst during inflammation - defects cause Chronic Granulomatous Disease. (4) Enzymatic metabolism of exogenous chemicals: CCl4 generates CCl3- radical. (5) Transition metals: iron (Fenton reaction: H2O2 + Fe2+ leads to Fe3+ + OH- + OH-) and copper donate/accept electrons catalyzing free radical formation - Fe3+ reduced to Fe2+ by O2-. (6) Nitric oxide (NO): generated by endothelial cells, macrophages, neurons - acts as free radical, converted to peroxynitrite anion (ONOO-), NO2, NO3-.<br><br><b>REMOVAL OF FREE RADICALS (Antioxidant Defenses)</b><br><br>(1) Antioxidant vitamins: lipid-soluble Vitamin E and Vitamin A, water-soluble Vitamin C (ascorbic acid), glutathione in cytosol. (2) Metal-binding proteins: transferrin, ferritin, lactoferrin, ceruloplasmin bind Fe and Cu preventing ROS generation. (3) Enzymatic scavengers: Catalase (peroxisomes) - decomposes H2O2 to O2 + H2O, Superoxide dismutase (SOD) - converts O2- to H2O2 (Mn-SOD in mitochondria, Cu-Zn-SOD in cytoplasm), Glutathione peroxidase - H2O2 + 2GSH leads to GSSG + 2H2O, GSH/GSSG ratio indicates cell oxidative state.<br><br><b>PATHOLOGIC EFFECTS OF FREE RADICALS</b><br><br>(1) Lipid peroxidation in membranes: O2- attacks double bonds in unsaturated fatty acids of membrane lipids, yields peroxides (unstable, reactive), autocatalytic chain reaction (propagation) causes extensive membrane damage. (2) Oxidative modification of proteins: oxidation of amino acid side chains, covalent protein-protein cross-links (disulfide bonds), oxidation of protein backbone, disrupts enzyme active sites, structural proteins, enhances proteasomal degradation of misfolded proteins. (3) DNA lesions: single and double-strand breaks, DNA strand cross-linking, adduct formation - implicated in cell aging and malignant transformation.<br><br><b>CLINICAL CONDITIONS INVOLVING FREE RADICALS</b><br><br>Ischemia-reperfusion injury (restoration of blood flow increases ROS burst), chemical and radiation injury, cellular aging (ROS damage to DNA and proteins), microbial killing by phagocytes (NADPH oxidase), neurodegenerative diseases (Alzheimer disease), carcinogenesis (oxidative DNA damage). ROS at controlled low doses serve physiologic functions in cellular receptor signaling.<br><br><b>KEY NEET PG HIGH-YIELD POINTS</b><br><br>First manifestation of cell injury: cellular swelling (hydropic change). Earliest change in reversible injury: mitochondrial swelling. Point of no return hallmarks: irreversible mitochondrial damage plus membrane disruption plus DNA damage. Nuclear changes in necrosis: pyknosis leads to karyorrhexis leads to karyolysis. Fenton reaction: H2O2 + Fe2+ generates OH- (most damaging radical). Chronic granulomatous disease: NADPH oxidase defect - failure to generate O2- in neutrophils. CCl4 toxicity: metabolism in liver generates CCl3- radical causing fatty change (reversible) progressing to necrosis (irreversible). Caseous necrosis + granuloma = tuberculosis. Liquefactive necrosis in brain = ischemic infarct. Fibrinoid necrosis = immune-mediated vascular injury. ENDOFFILE echo "Exit code: $?"

wc -l /home/daytona/workspace/anki/cell_injury_anki.txt && echo "---" && wc -c /home/daytona/workspace/anki/cell_injury_anki.txt && echo "---" && python3 -c " with open('/home/daytona/workspace/anki/cell_injury_anki.txt', 'r') as f: content = f.read() lines = content.split('\n') print(f'Lines (split by newline): {len(lines)}') print(f'Non-empty lines: {sum(1 for l in lines if l.strip())}') # Check TAB separator parts = lines[0].split('\t') if lines[0] else [] print(f'Tab-separated parts on line 1: {len(parts)}') print(f'Front: {parts[0][:80] if parts else \"NONE\"}') print(f'Back starts with: {parts[1][:80] if len(parts)>1 else \"NONE\"}') # Check for forbidden characters forbidden = ['|', ';'] for fc in forbidden: count = content.count(fc) print(f'Occurrences of \"{fc}\": {count}') "

cat > /home/daytona/workspace/anki/cell_injury_no_necrosis.txt << 'ENDOFFILE' Cell Injury - Reversible, Irreversible, Free Radicals <b>CAUSES OF CELL INJURY</b><br><br>Hypoxia/Ischemia (most common - depletes ATP via failure of oxidative phosphorylation), Toxins (CCl4, ethanol, drugs, CO, asbestos), Infectious agents (viruses, bacteria, fungi, parasites), Immunologic reactions (autoimmune, allergic, chronic inflammation), Genetic abnormalities (chromosomal defects, point mutations, enzyme defects), Nutritional imbalances (protein-calorie deficiency, vitamin deficiency, obesity), Physical agents (trauma, radiation, extreme temperature, electric shock).<br><br><b>REVERSIBLE CELL INJURY</b><br><br>Definition: Derangement of function and morphology that cells can RECOVER from if the damaging stimulus is removed. Key mechanism: failure of ATP-dependent Na+/K+ pump leads to Na+ influx, water influx, and cellular swelling. Earliest/first manifestation of almost all forms of cell injury: cellular swelling (hydropic change/vacuolar degeneration). Gross findings: pallor, increased turgor, increased organ weight. Light microscopy: small clear vacuoles in cytoplasm (distended pinched-off ER segments), fatty change (lipid vacuoles in liver), increased eosinophilia (loss of cytoplasmic RNA - RNA normally binds blue hematoxylin dye). Electron microscopy: (1) Plasma membrane blebbing, blunting, loss of microvilli, (2) Mitochondrial swelling with small amorphous densities, (3) Myelin figures in cytosol from phospholipids of damaged membranes, (4) ER dilation with detachment of ribosomes and dissociation of polysomes, (5) Nuclear chromatin clumping. Fatty change: occurs in organs involved in lipid metabolism (liver), results from toxic injury disrupting metabolic pathways causing rapid accumulation of triglyceride-filled vacuoles - a manifestation of reversible injury.<br><br><b>IRREVERSIBLE CELL INJURY</b><br><br>Occurs when injury persists beyond the "point of no return." Three consistent hallmarks: (1) Inability to restore mitochondrial function and oxidative phosphorylation/ATP generation even after removal of original insult, (2) Altered structure and loss of function of plasma membrane and intracellular membranes, (3) Loss of structural integrity of DNA and chromatin. Lysosomal membrane injury causes enzymatic digestion of the cell. Massive Ca2+ influx from extracellular space and from ER activates phospholipases (membrane degradation), proteases (protein breakdown), endonucleases (DNA fragmentation), and ATPases (depletes ATP). Earliest ultrastructural change seen by EM: mitochondrial swelling (reversible), then large amorphous intramitochondrial densities (hallmark of irreversible injury).<br><br><b>REVERSIBLE vs IRREVERSIBLE INJURY - KEY DISTINCTIONS</b><br><br>Reversible: cellular swelling, fatty change, membrane blebbing, ER dilation, chromatin clumping, small amorphous mitochondrial densities - ALL correctable on stimulus removal. Irreversible: massive mitochondrial swelling with large flocculent densities, plasma membrane disruption, lysosomal rupture, nuclear pyknosis/karyorrhexis/karyolysis - NOT correctable. Functional loss precedes morphologic changes - cells may be nonfunctional yet still viable with reversible injury. Cell death by necrosis typically precedes ultrastructural and light microscopic morphologic changes.<br><br><b>MECHANISMS OF CELL INJURY - KEY BIOCHEMICAL PATHWAYS</b><br><br>ATP depletion: reduced oxidative phosphorylation from hypoxia or mitochondrial damage leads to failure of Na+/K+ ATPase (cellular swelling), failure of Ca2+ pumps (Ca2+ accumulation), anaerobic glycolysis (lactic acidosis, pH drop, chromatin clumping), failure of protein synthesis, membrane lipid defects. Mitochondrial damage: permeability transition pore (PTP) opening, cytochrome c release into cytosol triggers apoptosis. ER stress: protein misfolding depletes essential proteins and triggers apoptosis if unfolded proteins accumulate. DNA damage: radiation or free radicals cause single/double-strand breaks triggering apoptosis if unrepairable. Ischemia-reperfusion injury: restoration of blood flow exacerbates damage by ROS burst from activated neutrophils and by increased inflammation.<br><br><b>FREE RADICALS AND OXIDATIVE STRESS - OVERVIEW</b><br><br>Definition: chemical species with a single unpaired electron in outer orbit - highly reactive, attack organic chemicals including proteins, lipids, carbohydrates, nucleic acids. Chain propagation: reacting molecules are themselves converted to free radicals (autocatalytic). Reactive Oxygen Species (ROS): most important class - O2- (superoxide anion, 1 electron), H2O2 (hydrogen peroxide, 2 electrons), OH- (hydroxyl radical, 3 electrons). Oxidative stress: excess free radicals due to increased production OR decreased scavenging. Conditions implicated: cell injury, cancer, aging, Alzheimer disease, atherosclerosis, ischemia-reperfusion injury, microbial killing.<br><br><b>GENERATION OF FREE RADICALS</b><br><br>(1) Normal metabolic processes: partial reduction of O2 during mitochondrial respiration generates O2-, H2O2, OH- as intermediates. (2) Radiant energy: UV light and x-rays hydrolyze water into OH- and H- radicals. (3) Activated leukocytes (neutrophils, macrophages): NADPH oxidase plasma membrane complex generates rapid ROS burst during inflammation - defect in NADPH oxidase causes Chronic Granulomatous Disease (failure to kill bacteria). Xanthine oxidase also generates O2-. (4) Exogenous chemical metabolism: CCl4 metabolized in liver ER generates CCl3- radical causing lipid peroxidation, fatty change (reversible) progressing to necrosis (irreversible). (5) Transition metals - Fenton reaction: H2O2 + Fe2+ leads to Fe3+ + OH- + OH- (iron must be in ferrous Fe2+ form, O2- reduces Fe3+ to Fe2+ to sustain reaction), copper similarly. (6) Nitric oxide (NO): generated by endothelial cells, macrophages, neurons - itself a free radical, converted to highly reactive peroxynitrite anion (ONOO-), NO2, and NO3-.<br><br><b>REMOVAL OF FREE RADICALS (Antioxidant Defense Systems)</b><br><br>Free radicals spontaneously decay: O2- dismutates to O2 and H2O2 in water. Enzymatic and non-enzymatic defenses include: (1) Antioxidant vitamins: Vitamin E and Vitamin A (lipid-soluble, protect membranes), Vitamin C - ascorbic acid (water-soluble), Glutathione (GSH) in cytosol. (2) Metal-binding proteins: transferrin, ferritin, lactoferrin bind iron - ceruloplasmin binds copper - prevent participation in ROS-generating reactions. (3) Enzymatic scavengers: Catalase (located in peroxisomes) - 2H2O2 leads to O2 + 2H2O, Superoxide dismutase (SOD) - 2O2- + 2H leads to H2O2 + O2 (Mn-SOD in mitochondria, Cu-Zn-SOD in cytoplasm), Glutathione peroxidase - H2O2 + 2GSH leads to GSSG + 2H2O - GSH/GSSG ratio is key indicator of cell oxidative state.<br><br><b>PATHOLOGIC EFFECTS OF FREE RADICALS</b><br><br>(1) Lipid peroxidation of membranes: O2- attacks double bonds in unsaturated fatty acids of plasma and organellar membranes, yields unstable reactive peroxides, autocatalytic chain reaction (propagation) causes extensive membrane damage. (2) Oxidative modification of proteins: oxidation of amino acid side chains, covalent protein-protein cross-links (disulfide bonds), oxidation of protein backbone, disrupts enzyme active sites and structural protein conformation, enhances proteasomal degradation of misfolded proteins. (3) DNA lesions: single and double-strand breaks, cross-linking of DNA strands, adduct formation - implicated in cellular aging and malignant transformation.<br><br><b>KEY NEET PG HIGH-YIELD FACTS</b><br><br>First manifestation of almost all cell injury: cellular swelling (hydropic change). ATP depletion: Na+/K+ pump fails leads to Na+ and water influx leads to cellular swelling. Hallmarks of irreversible injury: (a) large flocculent mitochondrial densities, (b) membrane disruption, (c) DNA damage. Fenton reaction: H2O2 + Fe2+ generates OH- (most damaging ROS). NADPH oxidase defect: Chronic Granulomatous Disease - failure of respiratory burst in neutrophils. CCl4 mechanism: CCl3- radical leads to lipid peroxidation of SER leads to fatty liver. Antioxidant enzymes: SOD converts O2- to H2O2, Catalase converts H2O2 to H2O, Glutathione peroxidase uses GSH to detoxify H2O2. Metal storage proteins prevent ROS: transferrin (iron transport), ferritin (iron storage), ceruloplasmin (copper). Ischemia-reperfusion injury: ROS burst on reperfusion worsens injury more than ischemia alone. Lipofuscin: wear-and-tear pigment from lipid peroxidation end-products - marker of aging and chronic oxidative stress. ENDOFFILE echo "Exit: $?"

wc -l /home/daytona/workspace/anki/cell_injury_no_necrosis.txt && python3 -c " with open('/home/daytona/workspace/anki/cell_injury_no_necrosis.txt', 'r') as f: content = f.read() lines = [l for l in content.split('\n') if l.strip()] print(f'Non-empty lines: {len(lines)}') parts = lines[0].split('\t') print(f'Tab-separated parts: {len(parts)}') print(f'Front: {parts[0]}') print(f'Back preview: {parts[1][:100]}') for fc in ['|', ';']: print(f'Occurrences of \"{fc}\": {content.count(fc)}') print(f'File size: {len(content)} bytes') "