Acute Inflammation: Cellular Events Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Acute Inflammation: Cellular Events. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Acute Inflammation: Cellular Events Indian Medical PG Question 1: Which of the following helps in cell-to-cell adhesion?
- A. Interleukins
- B. Interferons
- C. E-Cadherin (Correct Answer)
- D. Matrix metalloproteinases
Acute Inflammation: Cellular Events Explanation: ***E-Cadherin***
- E-Cadherin is a **cell adhesion molecule** that plays a crucial role in maintaining the structure of tissues by promoting **cell-to-cell adhesion** [1].
- It is mainly involved in the **adherens junctions**, helping cells stick together, especially in epithelial tissues.
*Matrix metallo proteinase*
- Matrix metallo proteinases (MMPs) are enzymes that degrade **extracellular matrix** components, rather than promoting adhesion between cells.
- They are involved in **tissue remodeling** and **wound healing**, not in direct cell-to-cell interactions.
*Interleukins*
- Interleukins are a group of **cytokines** that mediate **immune responses**, but they do not facilitate direct cell adhesion.
- Their primary function involves **cell signaling** and communication, rather than adhesion processes.
*Interferons*
- Interferons are signaling proteins involved in the **immune defense against viral infections** and do not have a role in cell-to-cell adhesion.
- They primarily act to induce an **antiviral state** in neighboring cells and modulate the immune response.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 314-315.
Acute Inflammation: Cellular Events Indian Medical PG Question 2: Most effective bactericidal system within phagocytes is-
- A. Cationic basic protein mediated
- B. Reactive oxygen metabolite mediated (Correct Answer)
- C. Lysozyme mediated
- D. Lactoferrin mediated
Acute Inflammation: Cellular Events Explanation: ***Reactive oxygen metabolite mediated***
- The production of **reactive oxygen metabolites** (like superoxide, hydrogen peroxide, and hydroxyl radicals) through the **respiratory burst** is a highly potent mechanism for killing phagocytosed bacteria.
- These highly reactive molecules cause **oxidative damage** to bacterial components, leading to their degradation and death.
*Cationic basic protein mediated*
- **Cationic proteins** (e.g., defensins) have antimicrobial properties by damaging bacterial membranes, but they are generally less potent than reactive oxygen species in overall bacterial killing within phagocytes.
- While important, they contribute to a broader array of antimicrobial mechanisms but are not considered the *most effective* single system.
*Lysozyme mediated*
- **Lysozyme** primarily targets bacterial **peptidoglycan**, breaking down bacterial cell walls, especially in gram-positive bacteria.
- It is an important antimicrobial enzyme, but its effectiveness is limited against many gram-negative bacteria with outer membranes and it is generally less destructive than the radical-forming reactive oxygen species.
*Lactoferrin mediated*
- **Lactoferrin** primarily acts by **chelating iron**, which is an essential nutrient for bacterial growth, thereby inhibiting bacterial proliferation.
- While important for bacteriostasis, its direct bactericidal activity is often limited compared to the direct damaging effects of reactive oxygen species.
Acute Inflammation: Cellular Events Indian Medical PG Question 3: All of the following are classical mediators of inflammation, except which of the following?
- A. Prostaglandins
- B. Interleukin-1 (IL-1)
- C. Tumour necrosis factor-alpha (TNF-alpha)
- D. Myeloperoxidase (MPO) (Correct Answer)
Acute Inflammation: Cellular Events Explanation: ***Myeloperoxidase***
- **Myeloperoxidase** is primarily an enzyme involved in the microbial killing process in neutrophils, not a typical mediator of inflammation.
- It catalyzes the production of **hypochlorous acid** (HOCl) during the oxidative burst, more related to pathogen destruction than inflammation mediation.
*Tumour necrosis factor-a (TNF-a)*
- **TNF-a** is a key pro-inflammatory cytokine that plays a significant role in systemic inflammation and is involved in the acute phase response [1][3].
- It promotes the recruitment of immune cells to sites of inflammation and is involved in the activation of the inflammatory process [1][3].
*Prostaglandins*
- **Prostaglandins** are lipid mediators derived from arachidonic acid that have various roles, including enhancing inflammation and pain signaling [1][2].
- They contribute to vasodilation, increased vascular permeability, and sensitization of nociceptors during inflammatory responses [1][2].
*Interleukin-1*
- **Interleukin-1** (IL-1) is a crucial inflammatory cytokine that stimulates immune responses and is involved in both acute and chronic inflammation [1][3].
- It can induce fever and promote the expression of adhesion molecules on endothelial cells, facilitating leukocyte migration [1][3].
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 101.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 95-96.
[3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 97-99.
Acute Inflammation: Cellular Events Indian Medical PG Question 4: The enzyme deficient in Lesch-Nyhan syndrome is:-
- A. PRPP synthetase
- B. Xanthine oxidase
- C. Hypoxanthine-guanine phosphoribosyltransferase (HPRT) (Correct Answer)
- D. Adenosine Deaminase
Acute Inflammation: Cellular Events Explanation: ***Hypoxanthine-guanine phosphoribosyltransferase (HPRT)***
- Lesch-Nyhan syndrome is caused by a severe deficiency of the enzyme **Hypoxanthine-guanine phosphoribosyltransferase (HPRT)**.
- This deficiency leads to an accumulation of **uric acid** and neurological abnormalities due to impaired purine salvage pathways.
*PRPP synthetase*
- **PRPP synthetase** is involved in the *de novo* purine synthesis pathway, and its overactivity can lead to hyperuricemia.
- While related to purine metabolism, a primary deficiency of PRPP synthetase is not the cause of Lesch-Nyhan syndrome.
*Xanthine oxidase*
- **Xanthine oxidase** is involved in the catabolism of purines, converting hypoxanthine to xanthine and xanthine to uric acid.
- Inhibition of xanthine oxidase (e.g., by allopurinol) is a treatment for hyperuricemia, but its deficiency does not cause Lesch-Nyhan syndrome.
*Adenosine Deaminase*
- A deficiency in **adenosine deaminase (ADA)** causes severe combined immunodeficiency (SCID) by leading to a buildup of toxic metabolites in lymphocytes.
- This enzyme is not directly involved in the pathogenesis of Lesch-Nyhan syndrome.
Acute Inflammation: Cellular Events Indian Medical PG Question 5: A major step in the pathogenesis of listeriosis is?
- A. The antiphagocytic activity of the L. monocytogenes capsule
- B. The release of hyaluronidase by L. monocytogenes, which contributes to its dissemination from local sites
- C. The formation of antigen-antibody complexes with resultant complement activation and tissue damage
- D. The survival and multiplication of L. monocytogenes within mononuclear phagocytes and host epithelial cells (Correct Answer)
Acute Inflammation: Cellular Events Explanation: ***The survival and multiplication of L. monocytogenes within mononuclear phagocytes and host epithelial cells***
- **Listeria monocytogenes** is a **facultative intracellular bacterium** that primarily infects and replicates within **macrophages** and epithelial cells. This intracellular survival helps it evade the host immune system and spread from cell to cell.
- Its ability to induce its own uptake (**internalin-mediated uptake**), escape the phagosome (via **listeriolysin O**), and move within the cytoplasm (via **ActA protein** for actin polymerization) are key to its pathogenesis and evasion of humoral immunity.
*The antiphagocytic activity of the L. monocytogenes capsule*
- While some bacteria use capsules for antiphagocytic activity, **Listeria monocytogenes** is not known for having a significant capsule as a primary virulence factor.
- Its main strategy for evading phagocytosis involves **intracellular survival** rather than external camouflage.
*The release of hyaluronidase by L. monocytogenes, which contributes to its dissemination from local sites*
- **Hyaluronidase** is an enzyme produced by some bacteria to break down hyaluronic acid in connective tissue, aiding in spread, but it is not a major virulence factor for **Listeria monocytogenes**.
- Listeria primarily disseminates through its **intracellular movement** and cell-to-cell spread, rather than extensive extracellular enzyme activity for tissue degradation.
*The formation of antigen-antibody complexes with resultant complement activation and tissue damage*
- This mechanism describes **Type III hypersensitivity reactions**, which involve the deposition of immune complexes leading to inflammation and tissue damage.
- While immune responses occur during listeriosis, this particular mechanism is not a major or primary step in the **pathogenesis** of the initial infection and spread of **Listeria monocytogenes**.
Acute Inflammation: Cellular Events Indian Medical PG Question 6: A patient with chronic granulomatous disease is most likely to have a defect in which enzyme?
- A. Superoxide dismutase
- B. Catalase
- C. Myeloperoxidase
- D. NADPH oxidase (Correct Answer)
Acute Inflammation: Cellular Events Explanation: ***NADPH oxidase***
- **Chronic granulomatous disease (CGD)** is characterized by a defect in **NADPH oxidase**, an enzyme critical for the formation of **superoxide radicals**.
- Without a functional **NADPH oxidase**, phagocytes cannot mount a **respiratory burst** to kill certain bacteria and fungi, leading to recurrent infections and granuloma formation.
*Superoxide dismutase*
- This enzyme converts **superoxide** into **hydrogen peroxide** and oxygen, an essential step in detoxifying reactive oxygen species.
- A defect here would lead to an accumulation of superoxide, but is not the primary cause of the susceptibility to specific infections seen in CGD.
*Catalase*
- **Catalase** breaks down **hydrogen peroxide** into water and oxygen, protecting cells from oxidative damage.
- While important for reducing oxidative stress, its deficiency is not responsible for the impaired microbial killing in CGD, rather, it's involved in the *breakdown* of products generated by NADPH oxidase.
*Myeloperoxidase*
- **Myeloperoxidase (MPO)** combines **hydrogen peroxide** with chloride ions to produce **hypochlorous acid (bleach)**, a potent microbicidal agent.
- Although crucial for killing, MPO can only function if NADPH oxidase first produces sufficient hydrogen peroxide; thus, its deficiency presents differently than CGD.
Acute Inflammation: Cellular Events Indian Medical PG Question 7: What is the main feature of chemotaxis as observed in white blood cells?
- A. Increased random movement of neutrophils
- B. Increased adhesiveness to intima
- C. Increased phagocytosis
- D. Unidirectional locomotion of neutrophils (Correct Answer)
Acute Inflammation: Cellular Events Explanation: ***Unidirectional locomotion of neutrophils***
- **Chemotaxis** refers to the **directional movement** of cells, such as neutrophils, towards a chemical attractant.
- This process is crucial for recruiting immune cells to sites of infection or inflammation.
*Increased random movement of neutrophils*
- While neutrophils do exhibit random movement, **chemotaxis** specifically describes **directed movement** along a chemical gradient, not merely an increase in random motion.
- **Random movement** without a specific direction does not effectively guide immune cells to a specific target.
*Increased adhesiveness to intima*
- **Adhesion to the intima** (endothelial cells) is an initial step in the process of leukocyte extravasation, allowing cells to roll and stick to vessel walls.
- However, it is primarily mediated by adhesion molecules and is distinct from the **directional migration** defined by chemotaxis.
*Increased phagocytosis*
- **Phagocytosis** is the process by which cells engulf pathogens or cellular debris.
- While essential for immune function, it is a separate function that occurs **after** the cell has migrated to its target via chemotaxis.
Acute Inflammation: Cellular Events Indian Medical PG Question 8: Arrange the following cellular events of inflammation in the correct sequence:
1. Rolling
2. Cytokine-mediated integrin activation
3. Adhesion
4. Migration
- A. 1,2,3,4 (Correct Answer)
- B. 3,4,1,2
- C. 2,1,4,3
- D. 4,1,2,3
Acute Inflammation: Cellular Events Explanation: ***1,2,3,4***
- The correct sequence of cellular events for leukocyte recruitment during inflammation begins with **rolling** [1], followed by **cytokine-mediated integrin activation** [2], then firm **adhesion** to the endothelium [1], and finally **migration** (diapedesis) into the tissues [3].
- This step-by-step process ensures effective targeting of leukocytes to the site of injury or infection [1].
*3,4,1,2*
- This sequence is incorrect as **adhesion** cannot occur before **rolling**, and **migration** is the final step after adhesion, not an early one.
- **Cytokine-mediated integrin activation** must precede firm adhesion [1].
*2,1,4,3*
- This order is incorrect because **rolling** (1) is the initial interaction that allows leukocytes to slow down on the endothelium [2], and it occurs before **cytokine-mediated integrin activation** (2) which strengthens the binding.
- **Migration** (4) is also misplaced as it should be the last step after firm adhesion (3).
*4,1,2,3*
- This sequence is incorrect as **migration** (4) is the last step in the process, not the first.
- **Rolling** (1) initiates the process by transiently interacting with endothelial cells, followed by activation and adhesion.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 87.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Migration in the tissues toward a chemotactic stimulus, pp. 86-87.
[3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 87-89.
Acute Inflammation: Cellular Events Indian Medical PG Question 9: Increased vascular permeability in acute inflammation is due to what?
- A. Histamine (Correct Answer)
- B. IL-2
- C. TGF-β
- D. FGF-2
Acute Inflammation: Cellular Events Explanation: ***Histamine***
- Histamine is a key **mediator** released during acute inflammation that causes **increased vascular permeability** by inducing **contraction of endothelial cells** [1][2].
- Its release contributes to the hallmark signs of inflammation, including **swelling** and **redness** [2].
*IL 2*
- IL 2 primarily functions as a **growth factor** for T cells, not directly influencing vascular permeability in acute inflammation.
- It is more involved in the **adaptive immune response** rather than in the acute phase of inflammation.
*TGF beta*
- TGF beta is primarily involved in **fibrosis** and **tissue repair** and does not play a direct role in increasing vascular permeability during acute phases.
- It acts more as an **anti-inflammatory** cytokine rather than a pro-inflammatory mediator.
*FGF*
- Fibroblast growth factor (FGF) is mainly involved in **angiogenesis** and wound healing rather than direct modulation of vascular permeability during acute inflammation.
- It does not contribute to **edema formation** associated with acute inflammatory responses.
**References:**
[1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 187-188.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 101.
Acute Inflammation: Cellular Events Indian Medical PG Question 10: Which of the following is/are characteristic features of chronic inflammation?
- A. Infiltration of neutrophils
- B. Tissue fibrosis and lymphocyte infiltration (Correct Answer)
- C. Increased blood flow (hyperemia)
- D. Presence of fluid accumulation (edema) in tissues
Acute Inflammation: Cellular Events Explanation: ***Tissue fibrosis and lymphocyte infiltration***
- **Chronic inflammation** is characterized by the persistent presence of lymphocytes, plasma cells, and macrophages as the predominant inflammatory cells [1].
- **Tissue fibrosis** (scarring) and destruction are hallmarks of chronic inflammation as the body attempts to repair ongoing damage, often leading to loss of organ function [1].
*Infiltration of neutrophils*
- **Neutrophils** are the primary inflammatory cells seen in **acute inflammation**, being the first responders to injury or infection [2].
- Their presence typically signifies an active, recent inflammatory process, usually resolving within hours to days.
*Increased blood flow (hyperemia)*
- **Hyperemia** is a classic sign of **acute inflammation**, contributing to the **redness and warmth** observed at the site.
- While some vascular changes can persist in chronic inflammation, pronounced and primary hyperemia is characteristic of the acute phase.
*Presence of fluid accumulation (edema) in tissues*
- **Edema** primarily results from increased vascular permeability, a key feature of **acute inflammation**, causing swelling [2].
- While some edema may be present in chronic inflammation due to persistent vascular leakage, it is a dominant feature of acute inflammatory responses.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 109-110.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 103-104.
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