Biochemistry
1 questionsWhich of the following is a positive acute phase protein that enhances the acute phase response?
NEET-PG 2015 - Biochemistry NEET-PG Practice Questions and MCQs
Question 491: Which of the following is a positive acute phase protein that enhances the acute phase response?
- A. Fibrinogen (Correct Answer)
- B. Transferrin
- C. Albumin
- D. Prealbumin
Explanation: ***Fibrinogen*** - **Fibrinogen** is a key **positive acute phase protein** whose concentration increases significantly during inflammation - Its elevation contributes to the acute phase response by promoting **blood clotting** and influencing **erythrocyte sedimentation rate (ESR)** - Along with C-reactive protein (CRP), haptoglobin, and serum amyloid A, fibrinogen is among the major positive acute phase reactants *Transferrin* - **Transferrin** is a **negative acute phase protein**, meaning its concentration decreases during inflammation - This reduction is part of the body's iron-sequestration strategy to limit iron availability for invading pathogens - The decrease in transferrin helps restrict bacterial growth by reducing available iron *Albumin* - **Albumin** is a prominent **negative acute phase protein**, with its concentration decreasing during acute inflammation due to redistribution and reduced synthesis - It plays a vital role in maintaining **oncotic pressure** and transporting various substances - Its decline reflects the severity of inflammation and is used as a marker of the acute phase response *Prealbumin* - **Prealbumin** (also known as transthyretin) is a **negative acute phase protein** and a sensitive marker of nutritional status - Its rapid decline during inflammation makes it a useful indicator, as its synthesis is quickly reduced - It has a short half-life (2-3 days), making it more sensitive to acute changes than albumin
Pathology
1 questionsWhich of the following is derived from fibroblast cells?
NEET-PG 2015 - Pathology NEET-PG Practice Questions and MCQs
Question 491: Which of the following is derived from fibroblast cells?
- A. MMP2
- B. Collagen (Correct Answer)
- C. Angiopoietin
- D. TGF-β
Explanation: ***Collagen*** - Collagen is a structural protein that is predominantly produced by **fibroblast cells** in the extracellular matrix [1][2]. - It provides tensile strength and structural support to various tissues, playing a crucial role in wound healing and tissue repair [2]. *TGF-13* - Transforming Growth Factor-beta 1 (TGF-β1) is primarily produced by **immune cells** and is involved in cell growth and differentiation, not primarily by fibroblasts. - It plays a role in **fibrosis** and inflammation, but is not directly synthesized by fibroblast cells themselves. *MMP2* - Matrix Metalloproteinase-2 (MMP-2) is produced by various cell types, including **endothelial and epithelial cells**, but not predominantly by fibroblasts. - It is involved in the degradation of **extracellular matrix** components rather than being a product of fibroblast synthesis. *Angiopoietin* - Angiopoietin is primarily secreted by **endothelial cells** and plays a significant role in blood vessel formation and maturation. - It is not derived from fibroblast cells and is unrelated to their primary function of producing the extracellular matrix. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 31-32. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. With Illustrations By, pp. 34-35.
Pharmacology
4 questionsWhat effect does morphine have on muscle tone?
Which drug is not administered as a transdermal patch?
Antidepressant drug used in nocturnal enuresis is:
What is the primary mechanism of action of zonisamide?
NEET-PG 2015 - Pharmacology NEET-PG Practice Questions and MCQs
Question 491: What effect does morphine have on muscle tone?
- A. Increased muscle tone (Correct Answer)
- B. Respiratory stimulation
- C. Decreased muscle tone
- D. Mydriasis
Explanation: ***Increased muscle tone*** - Morphine **increases skeletal muscle tone** and can cause muscle rigidity, particularly with rapid IV administration (truncal rigidity). - It significantly increases **smooth muscle tone** in various organs including the sphincter of Oddi (causing biliary colic), bladder sphincter (causing urinary retention), and GI tract (causing constipation). - This increased tone in sphincters and smooth muscle is a well-documented effect mediated through **opioid receptor activation**. *Bradycardia (not increased heart rate)* - Morphine typically causes **bradycardia** (decreased heart rate) due to vagal stimulation and central effects, not tachycardia. - Increased heart rate would be atypical and not a primary pharmacological effect of morphine. *Miosis (not mydriasis)* - Morphine characteristically causes **miosis** (pinpoint pupils) due to stimulation of the Edinger-Westphal nucleus of the oculomotor nerve. - Mydriasis (dilated pupils) is seen with anticholinergics or sympathomimetics, not opioids. *Respiratory depression (not stimulation)* - Morphine causes **respiratory depression**, not stimulation, by reducing the responsiveness of brainstem respiratory centers to CO2. - This is one of the most dangerous adverse effects and the primary cause of death in opioid overdose.
Question 492: Which drug is not administered as a transdermal patch?
- A. Morphine (Correct Answer)
- B. Fentanyl
- C. Clonidine
- D. Diclofenac
Explanation: ***Morphine*** - **Morphine** is generally not administered transdermally due to its **poor lipid solubility** [1] and **large molecular size**, which limit its ability to penetrate the skin effectively. - While experimental patches have been developed, they are **not widely available** or commonly used in clinical practice for systemic delivery. *Fentanyl* - **Fentanyl** is a potent opioid that is commonly administered via a **transdermal patch** for chronic pain management [2]. - Its **high lipid solubility** and small molecular size allow it to be effectively absorbed through the skin, providing sustained analgesia. *Clonidine* - **Clonidine** is an alpha-2 adrenergic agonist available as a **transdermal patch** for the treatment of **hypertension**. - The patch provides a **continuous and steady release** of the drug, leading to consistent blood pressure control. *Diclofenac* - **Diclofenac** is a non-steroidal anti-inflammatory drug (NSAID) available in **transdermal patch** formulations for topical pain relief. - These patches are used for localized pain conditions like **osteoarthritis** and provide targeted drug delivery with reduced systemic side effects.
Question 493: Antidepressant drug used in nocturnal enuresis is:
- A. Imipramine (Correct Answer)
- B. Fluoxetine
- C. Trazodone
- D. Sertraline
Explanation: ***Imipramine*** - **Imipramine**, a **tricyclic antidepressant (TCA)**, is frequently used off-label for **nocturnal enuresis** in children [1]. - Its mechanism of action in enuresis is thought to involve a combination of anticholinergic effects (which relax the bladder detrusor muscle) and central nervous system effects (which may increase bladder capacity and arousal from sleep) [1]. *Fluoxetine* - **Fluoxetine** is a **selective serotonin reuptake inhibitor (SSRI)** and is primarily used for depression, anxiety disorders, and OCD [2]. - It is not indicated for the treatment of nocturnal enuresis and does not have the same bladder-relaxing or arousal-modulating properties as imipramine in this context. *Trazodone* - **Trazodone** is a **serotonin antagonist and reuptake inhibitor (SARI)**, commonly prescribed for depression and insomnia due to its prominent sedative effects. - It is not used for nocturnal enuresis and its mechanism of action does not confer benefits for bladder control. *Sertraline* - **Sertraline** is another **selective serotonin reuptake inhibitor (SSRI)** used for a wide range of psychiatric conditions, including depression, anxiety, and panic disorder [2]. - Like fluoxetine, it is not an appropriate treatment for nocturnal enuresis and lacks the specific known effects beneficial for this condition.
Question 494: What is the primary mechanism of action of zonisamide?
- A. GABA receptors
- B. Cl- channels
- C. Sodium channels (Correct Answer)
- D. T-type calcium channels
Explanation: ***Sodium channels (Correct Answer)*** - Zonisamide's primary mechanism involves **blocking voltage-sensitive sodium channels**, which stabilizes neuronal membranes and inhibits repetitive neuronal firing. - This action helps to prevent the propagation of **seizure activity** in the brain. *GABA receptors* - While zonisamide has some weak effects on GABA, it is not its **primary mechanism of action** for antiepileptic efficacy. - Drugs like **benzodiazepines** and **barbiturates** primarily act by enhancing GABAergic transmission. *T-type calcium channels* - Zonisamide also blocks T-type calcium channels, contributing to its broad-spectrum antiepileptic activity, but this is a **secondary mechanism** compared to its sodium channel blockade. - **Ethosuximide** is a classic example of a drug primarily acting on T-type calcium channels, especially for absence seizures. *Cl- channels* - Zonisamide does not primarily act on **chloride channels**; these are often modulated by GABA receptors. - Drugs that act directly on chloride channels are not typically used as **antiepileptics** in the same way.
Physiology
3 questionsInterleukin responsible for Pyrexia is:
Which of the following statements is TRUE regarding the Bohr effect?
Chemotaxis is mediated by-
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 491: Interleukin responsible for Pyrexia is:
- A. IL1 (Correct Answer)
- B. IL4
- C. IL3
- D. IL8
Explanation: ***IL1*** - **Interleukin-1 (IL-1)** is a primary **endogenous pyrogen**, directly acting on the thermoregulatory center in the hypothalamus to induce fever. - It stimulates the production of **prostaglandin E2 (PGE2)**, which then alters the hypothalamic set point, leading to increased body temperature. *IL3* - **Interleukin-3 (IL-3)** is a **hematopoietic growth factor** that primarily stimulates the proliferation and differentiation of hematopoietic stem cells. - Its main role is in the development of various blood cell lineages, not directly in inducing fever. *IL4* - **Interleukin-4 (IL-4)** is a key cytokine in **allergic reactions** and **Th2 immune responses**, promoting B cell activation and IgE production. - It does not directly cause pyrexia; its primary functions are related to humoral immunity and immune regulation. *IL8* - **Interleukin-8 (IL-8)**, also known as **CXCL8**, is a potent **chemotactic factor** for neutrophils and other immune cells. - Its main function is to recruit inflammatory cells to sites of infection or injury, not to induce fever directly.
Question 492: Which of the following statements is TRUE regarding the Bohr effect?
- A. Decreased affinity of Hb to O2 is associated with increased pH & decreased CO2
- B. Decreased affinity of Hb to O2 is associated with increased pH & CO2
- C. Decreased affinity of Hb to O2 is associated with decreased pH & increased CO2 (Correct Answer)
- D. Decreased affinity of Hb to O2 is associated with decreased pH & decreased CO2
Explanation: ***Decreased affinity of Hb to O2 is associated with decreased pH & increased CO2*** - The **Bohr effect** describes how **hemoglobin's (Hb) affinity for oxygen (O2) decreases** in the presence of increased **acidity (decreased pH)** and higher **carbon dioxide (CO2)** concentrations. - This physiological adaptation ensures that O2 is **released more readily** to tissues that are actively metabolizing (e.g., muscle during exercise), as these tissues produce more CO2 and lactic acid, leading to a drop in pH. *Decreased affinity of Hb to O2 is associated with increased pH & decreased CO2* - An **increased pH** (more alkaline) and **decreased CO2** actually **increase Hb's affinity for O2**, shifting the oxygen dissociation curve to the left. - This scenario promotes **oxygen loading** onto hemoglobin, typically occurring in the lungs rather than O2 release in the tissues. *Decreased affinity of Hb to O2 is associated with increased pH & CO2* - This statement combines an **increased pH** (which increases Hb-O2 affinity) with **increased CO2** (which decreases Hb-O2 affinity), leading to a contradictory and incorrect physiological effect based on the Bohr principle. - The net effect of an increased pH would typically dominate in terms of O2 binding. *Decreased affinity of Hb to O2 is associated with decreased pH & decreased CO2* - While **decreased pH** does reduce Hb's affinity for O2, **decreased CO2** would tend to increase it. - Therefore, this combination does not accurately represent the primary conditions that lead to a significant decrease in Hb-O2 affinity as described by the Bohr effect in active tissues.
Question 493: Chemotaxis is mediated by-
- A. Histamine
- B. Leukotriene C4 and C3a
- C. Bradykinin
- D. Leukotriene B4 and C5a (Correct Answer)
Explanation: ***Leukotriene B4 and C5a*** - Both **Leukotriene B4** [2] and **C5a** [1] are potent **chemoattractants** that guide the migration of neutrophils and other immune cells to sites of inflammation. - They are crucial in amplifying the **immune response**, particularly during acute inflammatory reactions. *Histamine* - Primarily involved in **vasodilation** and increased **vascular permeability**, rather than mediating chemotaxis. - Does not specifically attract immune cells to sites of injury or infection like leukotrienes do. *Bradykinin* - Mainly functions in **pain sensation** and promoting **vascular permeability**, not as a direct chemotactic agent. - It influences inflammation but does not effectively recruit immune cells to tissues. *Leukotriene C4 and C3a* - **Leukotriene C4** is involved in bronchoconstriction, while **C3a** [1] has roles in the complement system but is less potent than C5a in chemotaxis. - These mediators have different primary roles in inflammation, lacking the specificity of B4 and C5a for leukocyte attraction. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 99-100. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 95-96.
Psychiatry
1 questionsWhich of the following is NOT a known side effect of lithium?
NEET-PG 2015 - Psychiatry NEET-PG Practice Questions and MCQs
Question 491: Which of the following is NOT a known side effect of lithium?
- A. Polyuria
- B. Nephropathy
- C. Ebstein's anomaly
- D. Hyperthyroidism (Correct Answer)
Explanation: ***Hyperthyroidism*** - Lithium commonly causes **hypothyroidism** by interfering with thyroid hormone synthesis and release, not hyperthyroidism. - Patients on lithium often require **thyroid function monitoring** and may need thyroid hormone supplementation. *Polyuria* - **Nephrogenic diabetes insipidus**, characterized by polyuria and polydipsia, is a common side effect of lithium. - Lithium interferes with the kidney's ability to respond to **vasopressin (ADH)**, leading to increased water excretion. *Nephropathy* - Chronic lithium use can lead to **interstitial nephropathy**, characterized by a reduction in glomerular filtration rate. - Long-term monitoring of **renal function** is crucial for patients on lithium therapy. *Ebstein's anomaly* - While not a general "side effect" in adults, **Ebstein's anomaly** is a congenital heart defect associated with lithium exposure during the first trimester of pregnancy. - It involves displacement of the **tricuspid valve leaflets** into the right ventricle.