NEET-PG 2015 Practice Questions

Q: Which of the following is a positive acute phase protein that enhances the acute phase response?

Fibrinogen. ***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

Q: Which drug is contraindicated before delivery of the baby (during first and second stages of labor)?

Ergometrine. ***Ergometrine*** - **Ergometrine** is a potent uterotonic agent that causes **tetanic (sustained) uterine contractions**. - It is **absolutely contraindicated before delivery of the baby** (during first and second stages of labor) because: - Sustained contractions lead to **fetal hypoxia** and **fetal distress** by reducing placental blood flow - Risk of **uterine rupture** due to excessive uterine tone - **Obstructed labor** and **cervical lacerations** from forcing delivery against sustained contraction - Ergometrine is **only used after delivery of the baby** in the third stage for active management and prevention of postpartum hemorrhage. *Mifepristone* - **Mifepristone** is an antiprogesterone used for medical abortion in early pregnancy or cervical ripening before labor induction. - It is not relevant during active labor as it acts by blocking progesterone receptors, not by causing immediate uterine contractions. *Oxytocin* - **Oxytocin** is the drug of choice for induction and augmentation of labor. - It causes **rhythmic, intermittent contractions** that allow for adequate placental perfusion between contractions. - Safe to use during first and second stages when properly monitored. *Misoprostol* - **Misoprostol** is a prostaglandin E1 analog used for cervical ripening and labor induction. - Can be used before and during labor for induction, though requires careful monitoring. - Unlike ergometrine, it does not cause sustained tetanic contractions when used in appropriate doses.

Q: Which antibody is primarily associated with warm autoimmune hemolytic anemia (AIHA)?

IgG. ***IgG*** - **Warm autoimmune hemolytic anemia (AIHA)** is primarily associated with **IgG antibodies**, which mediate hemolysis at body temperature [1]. - IgG antibodies typically bind to red blood cells and lead to their destruction by the **reticuloendothelial system** [1]. *IgM* - Often involved in **cold agglutinin disease**, not warm AIHA, as it primarily reacts at lower temperatures [2]. - Usually results in **hemolysis** in peripheral areas, like the extremities, rather than at normal body temperature [2]. *IgD* - Known primarily as a marker on **B cells**, it plays a minimal role in hemolytic anemia and is not involved in antibody-mediated hemolysis. - Lack of significant **serological presence** in autoimmune hemolytic processes makes it an unlikely candidate. *IgE* - Primarily associated with **allergic reactions** and parasitic infections rather than autoimmune hemolytic conditions [2]. - Does not typically participate in **hemolysis** or bind to red blood cells in AIHA.

Q: What is the typical lifespan of neonatal red blood cells (RBCs)?

60-90 days. ***60-90 days*** - The typical lifespan of **neonatal red blood cells (RBCs)** is **60-90 days**, which is **shorter than adult RBCs** (120 days). - This reduced lifespan is due to **increased membrane fragility**, **higher metabolic rate**, and **immature enzyme systems** in neonatal erythrocytes. - Neonatal RBCs contain more **fetal hemoglobin (HbF)** and have structural differences that contribute to their shorter survival. - This shorter lifespan contributes to the **physiological anemia of infancy** seen in the first few months of life. *90-120 days* - This range represents the typical lifespan of **adult RBCs**, not neonatal RBCs. - Neonatal RBCs have a **demonstrably shorter lifespan** compared to adult erythrocytes. - Confusing adult and neonatal RBC lifespans is a common error in clinical practice. *120-150 days* - This range is **longer than even adult RBC lifespan** (typically 120 days). - This would be **highly atypical** for any normal erythrocyte population. *150-200 days* - This represents an **abnormally prolonged** RBC lifespan not seen in normal physiology. - Such extended survival would suggest **pathological conditions** affecting RBC destruction or measurement error.

Q: Which of the following statements about glucocorticoids is true?

Glucocorticoids downregulate MHC class II expression.. ***Glucocorticoids downregulate MHC class II expression.*** - Glucocorticoids exert **immunosuppressive effects** by reducing the expression of **MHC class II molecules** on antigen-presenting cells. - This downregulation impairs the ability of antigen-presenting cells to activate **CD4+ T-helper cells**, thereby suppressing adaptive immune responses. *Glucocorticoids directly activate T-helper cells.* - Glucocorticoids do not directly activate T-helper cells; rather, they have an **inhibitory effect** on T-cell function and proliferation. - They tend to promote **T-cell apoptosis** and reduce cytokine production, thus dampening T-helper cell responses. *Glucocorticoids have no effect on immune cells.* - This statement is incorrect as glucocorticoids have profound and widespread **immunosuppressive and anti-inflammatory effects** on various immune cells. - They influence the function, proliferation, and survival of **lymphocytes, macrophages, and granulocytes**. *Glucocorticoids enhance the activity of cytotoxic T cells.* - Glucocorticoids generally **suppress immune responses**, including the activity of **cytotoxic T cells (CTLs)**, rather than enhancing it. - They tend to inhibit the production of **interleukins** necessary for CTL activation and proliferation.

Q: Volume of distribution of a drug is 500 ml and target concentration of drug in blood is 5 g/L. 20% of administered drug is reached to systemic circulation. What will be the loading dose of that drug -

12.5 gm. ***12.5 gm*** - The formula for loading dose (LD) is: LD = (Target Concentration × Volume of Distribution) / Bioavailability. - Given: Target Concentration = 5 g/L, Volume of Distribution = 500 mL = 0.5 L, Bioavailability = 20% = 0.2. - So, LD = (5 g/L × 0.5 L) / 0.2 = 2.5 g / 0.2 = **12.5 g**. *1 gm* - This value would be obtained if the target concentration was 2 g/L with 100% bioavailability, or if the calculation incorrectly handled the volume or bioavailability factor. - It does not account for the specified **bioavailability of 20%** or the given target concentration and volume of distribution. *5 gm* - This result would be obtained if the bioavailability was assumed to be 50% (LD = 2.5 g / 0.5 = 5 g), or if the volume of distribution was incorrectly used in the calculation. - This option does not correctly factor in the **20% bioavailability** of the administered drug. *25 gm* - This value would result from mistakes such as dividing by bioavailability of 10% instead of 20% (LD = 2.5 g / 0.1 = 25 g), or by multiplying bioavailability instead of dividing by it. - This answer significantly **overestimates** the required dose, which could lead to drug toxicity.

Q: Regarding the concepts of efficacy and potency of a drug, which of the following statements is FALSE?

ED50 of the drug corresponds to efficacy. ***ED50 of the drug corresponds to efficacy*** - **ED50** (median effective dose) is the dose at which 50% of individuals exhibit the specified effect; it quantifies **potency**, not efficacy. - **Efficacy** refers to the maximum effect a drug can produce, while potency refers to the amount of drug needed to produce an effect. *In a clinical setup, efficacy is more important than potency* - **Efficacy** determines the maximal therapeutic benefit a drug can achieve for a patient, making it crucial for clinical outcomes. - While **potency** influences the dose required, a highly potent drug that is not very efficacious may not be clinically useful. *Drugs that produce a similar pharmacological effect can have different levels of efficacy* - Two drugs might act on the same receptor but elicit different maximal responses, indicating varying **efficacy**. - For example, a **partial agonist** and **full agonist** interacting with the same receptor will have different efficacies. *In the log dose response curve, the height of the curve corresponds with efficacy* - The **maximal response** or plateau of the dose-response curve represents the **efficacy** of a drug. - A higher plateau on the curve indicates a drug with greater intrinsic activity achieving a larger effect.

Q: What is the primary mechanism of action of zonisamide?

Sodium channels. ***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.

Q: Antidepressant drug used in nocturnal enuresis is:

Imipramine. ***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 1

Which of the following is a positive acute phase protein that enhances the acute phase response?

Accepted Answer

Fibrinogen

Answer

Transferrin

Answer

Albumin

Answer

Prealbumin

Question 2

Which drug is contraindicated before delivery of the baby (during first and second stages of labor)?

Accepted Answer

Ergometrine

Answer

Mifepristone

Answer

Oxytocin

Answer

Misoprostol

Question 3

Which antibody is primarily associated with warm autoimmune hemolytic anemia (AIHA)?

Accepted Answer

IgG

Answer

IgE

Answer

IgM

Answer

IgD

Question 4

What is the typical lifespan of neonatal red blood cells (RBCs)?

Accepted Answer

60-90 days

Answer

120-150 days

Answer

150-200 days

Answer

90-120 days

Question 5

A 47-year-old woman presents with complaints of nervousness and increased sensitivity to hot weather. She is diagnosed with hyperthyroidism and prescribed propylthiouracil. What is the principal mechanism by which this drug acts?

Accepted Answer

Inhibiting the enzyme thyroid peroxidase, which reduces the synthesis of thyroid hormones.

Answer

Reducing the proteolysis of thyroglobulin.

Answer

Inhibiting the binding of TSH to its receptor.

Answer

Altering the levels of reverse T3 (rT3) in the body.

Question 6

Which of the following statements about glucocorticoids is true?

Accepted Answer

Glucocorticoids downregulate MHC class II expression.

Answer

Glucocorticoids directly activate T-helper cells.

Answer

Glucocorticoids have no effect on immune cells.

Answer

Glucocorticoids enhance the activity of cytotoxic T cells.

Question 7

Volume of distribution of a drug is 500 ml and target concentration of drug in blood is 5 g/L. 20% of administered drug is reached to systemic circulation. What will be the loading dose of that drug -

Accepted Answer

12.5 gm

Answer

1 gm

Answer

5 gm

Answer

25 gm

Question 8

Regarding the concepts of efficacy and potency of a drug, which of the following statements is FALSE?

Accepted Answer

ED50 of the drug corresponds to efficacy

Answer

Drugs that produce a similar pharmacological effect can have different levels of efficacy

Answer

In a clinical setup, efficacy is more important than potency

Answer

In the log dose response curve, the height of the curve corresponds with efficacy

Question 9

What is the primary mechanism of action of zonisamide?

Accepted Answer

Sodium channels

Answer

GABA receptors

Answer

Cl- channels

Answer

T-type calcium channels

Question 10

Antidepressant drug used in nocturnal enuresis is:

Accepted Answer

Imipramine

Answer

Fluoxetine

Answer

Trazodone

Answer

Sertraline

NEET-PG 2015

Biochemistry

Obstetrics and Gynecology

Pathology

Pediatrics

Pharmacology