Inflammation: Acute and Chronic Types

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Questions and Answers

A researcher is investigating the role of cell adhesion molecules during leukocyte extravasation. If they observe impaired transmigration of neutrophils across the endothelium in an in vitro model, which specific molecule is most likely deficient or non-functional, considering its direct involvement in diapedesis?

ICAM-1 (Intercellular Adhesion Molecule-1), crucial for the firm adhesion of leukocytes to endothelial cells.

E-selectin, responsible for the initial rolling of leukocytes along the endothelial surface.

PECAM-1 (Platelet Endothelial Cell Adhesion Molecule-1), integral in the process of leukocyte diapedesis. (correct)

VCAM-1 (Vascular Cell Adhesion Molecule-1), mediating leukocyte adhesion, particularly of lymphocytes, to activated endothelium.

A patient presents with a localized area of acute suppurative inflammation characterized by a central necrotic zone filled with purulent exudate, walled off by a layer of fibrin. Which enzymatic activity, if inhibited, would most effectively prevent the progression from a localized abscess to a diffuse cellulitis?

Inhibition of elastase, decreasing the breakdown of structural proteins in the affected tissue.

Inhibition of catalase, preventing the conversion of hydrogen peroxide into water and oxygen within phagosomes.

Inhibition of myeloperoxidase (MPO), reducing the oxidative burst within neutrophils.

Inhibition of hyaluronidase, limiting the degradation of extracellular matrix components. (correct)

In the context of acute inflammation, which of the following best describes the sequential order of events immediately following vasodilation and increased vascular permeability?

Transmigration → Adhesion → Margination → Chemotaxis → Phagocytosis

Margination → Adhesion → Transmigration → Chemotaxis → Phagocytosis (correct)

Chemotaxis → Margination → Adhesion → Transmigration → Phagocytosis

Adhesion → Margination → Chemotaxis → Transmigration → Phagocytosis

Consider a scenario where a novel anti-inflammatory drug selectively inhibits the production of specific eicosanoids. If the drug leads to a marked reduction in vasodilation and vascular permeability at the site of inflammation, which specific eicosanoid synthesis pathway is most likely being targeted?

The cyclooxygenase (COX) pathway, critical for the production of prostaglandins and thromboxanes. (A) Signup and view all the answers

A researcher is investigating the mechanisms of phagocytosis. They observe that macrophages are able to efficiently engulf bacteria coated with IgG antibodies or complement C3b. Which stage of phagocytosis is most directly enhanced by these opsonins?

The recognition and attachment stage, facilitating binding of the phagocyte to the target. (A) Signup and view all the answers

In a case of acute inflammation following a bacterial infection, which of the following scenarios would most likely lead to a progression towards chronic inflammation rather than complete resolution?

Persistent infection, repeated episodes of acute inflammation, or extensive tissue necrosis. (D) Signup and view all the answers

Which of the following chemical mediators primarily contributes to vasodilation during the early stages of acute inflammation through its action on vascular smooth muscle?

Histamine, released from mast cells and basophils, causing vasodilation and increased permeability. (A) Signup and view all the answers

Following tissue injury, a cascade of events leads to the production of pus. Which of the following statements accurately describes the composition of pus in the context of acute suppurative inflammation?

A purulent exudate composed of fluid with minimal fibrin content, dead neutrophils, necrotic tissue, and bacteria. (C) Signup and view all the answers

A researcher is studying the effects of specific cytokines on neutrophil chemotaxis in vitro. Which class of endogenous mediators would be most directly involved in attracting neutrophils to the site of inflammation, guiding their migration along a concentration gradient?

Chemokines, a family of cytokines that act as chemoattractants for leukocytes. (B) Signup and view all the answers

In the context of acute inflammation, consider a scenario where both vasodilation and increased vascular permeability are significantly upregulated. Which of the following downstream effects is most directly attributable to these vascular changes?

Increased hydrostatic pressure in the interstitial space, leading to fluid exudation. (A) Signup and view all the answers

In the context of chronic granulomatous inflammation, which of the following scenarios would most strongly suggest a diagnosis of sarcoidosis over tuberculosis, assuming all other diagnostic criteria are equivalent?

Detection of non-caseating granulomas with Schaumann bodies and asteroid bodies on biopsy. (C) Signup and view all the answers

Consider a patient presenting with a chronic skin lesion. Histopathological examination reveals granulomas with multinucleated giant cells engulfing birefringent particles. Polarized light microscopy identifies these particles as silica. Which of the following cellular mechanisms is MOST crucial in the pathogenesis of this granulomatous response?

Frustrated phagocytosis by macrophages, leading to chronic inflammation and granuloma formation. (C) Signup and view all the answers

A researcher is investigating the dynamics of pus formation in abscesses. If they were to introduce a potent inhibitor of Fibrinolysin, which of the following outcomes would MOST likely be observed in an experimental model of Streptococcus pyogenes induced cellulitis?

Decreased spread of the cellulitis with enhanced localization and potential abscess formation. (A) Signup and view all the answers

In the context of acute appendicitis progressing to peritonitis, which enzymatic activity is MOST directly implicated in the transition from a localized inflammatory response to a diffuse, life-threatening condition?

Hyaluronidase-driven breakdown of extracellular matrix components, facilitating bacterial dissemination. (B) Signup and view all the answers

Which of the following statements BEST encapsulates the critical distinction between an abscess and cellulitis, considering both the causative organism and the host's immune response?

Abscesses are characterized by a localized collection of pus walled off by a fibrous capsule, often caused by Staphylococcus aureus, whereas cellulitis presents as a diffuse spreading inflammation typically caused by Streptococcus pyogenes. (D) Signup and view all the answers

In a comparative study of acute inflammatory responses, researchers induce pleuritis in two groups of mice. One group develops fibrinous pleuritis, while the other develops serous pleuritis. Which of the following findings would MOST strongly support the conclusion that the fibrinous pleuritis is associated with a greater degree of vascular damage and permeability?

Higher concentration of fibrinogen and fibrin degradation products in the pleural fluid of mice with fibrinous pleuritis. (C) Signup and view all the answers

Consider a patient presenting with a carbuncle on the back of their neck. Gram staining reveals Gram-positive cocci in clusters. Given the patient's history of poorly controlled diabetes mellitus, which of the following virulence factors produced is MOST likely contributing to the formation of multiple communicating abscesses?

Coagulase, which promotes fibrin clot formation, creating barriers that protect bacteria from phagocytosis and antibiotics. (D) Signup and view all the answers

A researcher is studying the pathogenesis of cat scratch disease. They hypothesize that the formation of suppurative granulomas is dependent on a specific bacterial factor. Which of the following mechanisms is MOST likely responsible for the liquefactive necrosis observed within these granulomas?

Activation of the inflammasome pathway in macrophages, leading to the release of IL-1β and subsequent pyroptosis. (A) Signup and view all the answers

A patient presents with chronic rhinitis characterized by excessive mucus production. Analyzing a nasal swab sample, which of the following findings would be MOST indicative of catarrhal inflammation?

Profuse secretion of mucin glycoproteins, leading to a viscous, cloudy nasal discharge. (D) Signup and view all the answers

Following a severe burn injury, a patient develops extensive serous inflammation characterized by significant edema. Which of the following mechanisms MOST directly contributes to the formation of this protein-poor edema fluid?

Increased vascular permeability due to endothelial cell contraction mediated by histamine and bradykinin. (C) Signup and view all the answers

Consider a scenario where a previously healthy individual develops a localized inflammatory response following exposure to a novel synthetic chemical compound. Proteomic analysis of the exudate reveals a disproportionately high concentration of a specific subset of IgM antibodies, alongside elevated levels of High-Mobility Group Box 1 (HMGB1). Which of the following mechanisms is MOST likely driving the observed inflammatory response?

HMGB1-mediated activation of TLR4 on neutrophils and macrophages, synergistically amplifying the inflammatory cascade in conjunction with the IgM response. (D) Signup and view all the answers

A researcher is investigating the effects of a novel anti-inflammatory compound on neutrophil chemotaxis in vitro. Using a microfluidic chemotaxis chamber, they observe that neutrophils exposed to the compound exhibit normal initial migratory velocity towards a gradient of CXCL8, but demonstrate a significantly reduced ability to maintain persistent directional movement and frequently change direction. Which of the following intracellular signaling pathways is MOST likely being directly disrupted by this novel compound?

PI3K/Akt signaling, which is crucial for establishing and maintaining cell polarity and directed movement during chemotaxis. (B) Signup and view all the answers

A patient presents with a chronic inflammatory condition characterized by the presence of non-caseating granulomas in multiple organs. Histological analysis reveals the presence of epithelioid macrophages and multinucleated giant cells, but notably absent are T helper 17 (Th17) lymphocytes. Which of the following cytokines is LEAST likely to be playing a significant role in the formation and maintenance of these granulomas?

Interleukin-17 (IL-17), primarily associated with neutrophil recruitment and defense against extracellular bacteria and fungi. (D) Signup and view all the answers

In the context of acute inflammation, consider a scenario where a patient develops severe septic shock secondary to a Gram-negative bacterial infection. Despite aggressive antibiotic therapy and fluid resuscitation, the patient's blood pressure remains critically low. Further investigation reveals excessive production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) in vascular smooth muscle cells. Which of the following therapeutic interventions would MOST directly address the underlying pathophysiology contributing to the refractory hypotension?

Administration of a specific iNOS inhibitor to reduce excessive nitric oxide production. (A) Signup and view all the answers

A research team is investigating the molecular mechanisms underlying the transition from acute to chronic inflammation in a murine model of pulmonary fibrosis. They observe a persistent elevation of intracellular reactive oxygen species (ROS) within alveolar macrophages, despite resolution of the initial inflammatory stimulus. Which of the following signaling pathways is MOST likely being activated by this chronic ROS exposure, thereby contributing to the sustained fibrotic response?

Activation of the TGF-β/Smad pathway, leading to increased synthesis of extracellular matrix components and fibroblast differentiation. (C) Signup and view all the answers

A 45-year-old patient with a history of recurrent bacterial infections presents with splenomegaly and elevated levels of serum amyloid A (SAA). A biopsy of the spleen reveals extensive deposition of amyloid fibrils. Mass spectrometry analysis identifies the amyloid protein as AL amyloid, derived from immunoglobulin light chains. Which of the following underlying conditions is MOST likely driving the observed amyloid deposition in this patient?

Multiple myeloma, resulting in overproduction of immunoglobulin light chains and AL amyloidosis. (B) Signup and view all the answers

Consider a scenario where a patient undergoing treatment for rheumatoid arthritis with a TNF-α inhibitor develops a disseminated Mycobacterium tuberculosis infection. Which of the following mechanisms BEST explains the increased susceptibility to tuberculosis in this patient population?

TNF-α inhibition impairs the formation and maintenance of granulomas, which are essential for containing mycobacterial infections. (D) Signup and view all the answers

A researcher is investigating the role of inflammasomes in the pathogenesis of gout, a condition characterized by monosodium urate (MSU) crystal-induced inflammation. They observe that macrophages exposed to MSU crystals release large amounts of IL-1β. Which of the following intracellular events is MOST critical for the activation of the NLRP3 inflammasome in this context?

Increased intracellular potassium efflux, causing a conformational change in NLRP3 and promoting its assembly. (C) Signup and view all the answers

A 60-year-old patient with a long-standing history of poorly controlled type 2 diabetes mellitus develops a chronic, non-healing ulcer on their foot. Histological examination of the ulcer bed reveals extensive fibrosis, impaired angiogenesis, and reduced numbers of both neutrophils and macrophages. Which of the following molecular mechanisms is MOST likely contributing to the impaired wound healing in this patient?

Impaired activation of the hypoxia-inducible factor 1-alpha (HIF-1α) pathway, resulting in reduced expression of angiogenic factors like VEGF. (A) Signup and view all the answers

A researcher is studying the effects of a novel therapeutic agent on the resolution of inflammation in a mouse model of acute lung injury. They observe that administration of the agent promotes the efferocytosis of apoptotic neutrophils by alveolar macrophages. Which of the following receptors on alveolar macrophages is MOST likely mediating this enhanced efferocytosis?

Mer tyrosine kinase (MerTK), which recognizes phosphatidylserine exposed on the surface of apoptotic cells. (D) Signup and view all the answers

Flashcards

Inflammation

A local response of living tissue to injury, involving blood vessels and inflammatory cells.

Causes of Inflammation

Infection, tissue injury, or immune reactions causing inflammation.