Microbiology
1 questionsWhich of the following statements about interleukin-1 is false?
NEET-PG 2013 - Microbiology NEET-PG Practice Questions and MCQs
Question 651: Which of the following statements about interleukin-1 is false?
- A. IL-1 is an endogenous pyrogen.
- B. The primary source of IL-1 is the monocyte-macrophage system.
- C. IL-1 inhibits IL-2 production by T-cells. (Correct Answer)
- D. IL-1 promotes acute phase protein synthesis in the liver.
Explanation: ***IL-1 inhibits IL-2 production by T-cells*** - This statement is false because **IL-1** actually **enhances the production of IL-2** by T-cells, which is crucial for T-cell proliferation and immune response. - **IL-1 acts synergistically with IL-6 and TNF-α** to promote inflammation and immune cell activation, where IL-2 plays a key role. *The primary source of IL-1 is the monocyte-macrophage system* - This statement is true; **monocytes and macrophages** are the main producers of **IL-1α and IL-1β** upon activation by various stimuli. - Other cells, such as neutrophils, dendritic cells, and endothelial cells, can also produce IL-1, but monocytes and macrophages are the predominant source. *IL-1 is an endogenous pyrogen* - This statement is true; **IL-1** is a potent **endogenous pyrogen** that acts on the hypothalamus to induce fever, a hallmark of the acute phase response. - It triggers prostaglandin synthesis in the hypothalamus, leading to an elevation in the body's thermoregulatory set point. *IL-1 promotes acute phase protein synthesis in the liver* - This statement is true; **IL-1** is a key mediator that stimulates **hepatocytes** to produce **acute phase proteins**, such as C-reactive protein and serum amyloid A. - This hepatic response is part of the innate immune system's effort to control infection and inflammation.
Obstetrics and Gynecology
2 questionsWhich of the following is classified as a third generation Intrauterine Contraceptive Device (IUCD)?
Which among the following is an absolute contraindication of Hormone replacement therapy?
NEET-PG 2013 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 651: Which of the following is classified as a third generation Intrauterine Contraceptive Device (IUCD)?
- A. Mirena (Correct Answer)
- B. Nova-T
- C. Lippe's loop
- D. CuT-200
Explanation: ***Mirena*** - Mirena (levonorgestrel-releasing intrauterine system) is a **third-generation IUCD** that releases **progestin**, offering both contraceptive and therapeutic benefits. - Its mechanism of action involves **thickening cervical mucus**, thinning the uterine lining, and inhibiting sperm motility/viability. *Nova-T* - Nova-T is a **second-generation IUCD** that uses **copper** as its active contraceptive agent. - Copper IUCDs like Nova-T primarily work by causing a **sterile inflammatory reaction** in the uterus, making it spermicidal. *Lippe's loop* - Lippe's loop is a **first-generation IUCD** made of inert plastic, designed to **physically block** fertilization. - It is no longer widely used due to higher rates of expulsion and complications compared to newer generations. *CuT-200* - CuT-200 is a **second-generation IUCD** that releases **copper** to prevent pregnancy. - It works by producing a **local inflammatory response** in the uterus that is toxic to sperm and eggs.
Question 652: Which among the following is an absolute contraindication of Hormone replacement therapy?
- A. Endometriosis
- B. Heart disease
- C. Breast carcinoma (Correct Answer)
- D. Osteoarthritis
Explanation: ### Breast carcinoma - Hormone replacement therapy (HRT) is **contraindicated** in breast carcinoma because many breast cancers are **estrogen-receptor positive**, meaning estrogen can stimulate their growth [1]. - Using HRT in patients with a history of breast cancer significantly increases the risk of **recurrence** or **progression** of the disease [1]. *Endometriosis* - Endometriosis is not an **absolute contraindication**; HRT can sometimes be used in women with a history of endometriosis, especially if a hysterectomy and bilateral oophorectomy have been performed. - However, unopposed estrogen therapy might **exacerbate** remaining endometrial implants, so a combined estrogen-progestin regimen is typically preferred [1]. *Heart disease* - While HRT has been shown to have **risks** in women with established coronary heart disease, it is not an absolute contraindication for all forms of heart disease. - The **Women's Health Initiative study** demonstrated increased cardiovascular events in older women initiating HRT, but current guidelines suggest that timing of initiation is crucial and benefits may outweigh risks for younger postmenopausal women. *Osteoarthritis* - Osteoarthritis is **not a contraindication** to HRT; in fact, some studies suggest that estrogen may have protective effects on cartilage [2]. - HRT is neither a treatment nor a contraindication for osteoarthritis and does not significantly impact its progression or severity [2].
Pharmacology
7 questionsWhich of the following is the most potent topical corticosteroid?
Which of the following reduces the efficacy of oral contraceptives?
Visual field monitoring is important before starting which of the following drugs for epilepsy treatment?
Which of the following is a tricyclic antidepressant?
What is the drug of choice for pheochromocytoma?
What is the mechanism of action of Warfarin?
Which of the following is a classic tricyclic antidepressant (TCA) commonly used as the prototype for the class?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 651: Which of the following is the most potent topical corticosteroid?
- A. Triamcinolone acetonide
- B. Hydrocortisone acetate
- C. Clobetasol propionate (Correct Answer)
- D. Betamethasone valerate
Explanation: ***Clobetasol propionate*** - **Clobetasol propionate** is recognized as one of the most potent **Class I topical corticosteroids**, used for severe inflammatory skin conditions. - Its high potency allows for effective suppression of severe inflammation and pruritus, but also carries a greater risk of **adverse effects** with prolonged use. *Triamcinolone acetonide* - **Triamcinolone acetonide** is a **medium-potency** topical corticosteroid (Class IV-V), less potent than clobetasol propionate. - It is commonly used for moderate inflammatory skin conditions, such as eczema and psoriasis, but not for severe cases requiring maximum potency. *Hydrocortisone acetate* - **Hydrocortisone acetate** is a **low-potency** topical corticosteroid (Class VII), making it the least potent option listed. - It's often used for mild inflammatory conditions, sensitive areas like the face, or for less severe conditions requiring minimal corticosteroid strength. *Betamethasone valerate* - **Betamethasone valerate** is a **medium-to-high potency** topical corticosteroid (Class III-V), placing it among stronger corticosteroids but still less potent than clobetasol propionate. - It is effective for moderate to severe inflammatory skin conditions but does not reach the highest level of potency demonstrated by clobetasol.
Question 652: Which of the following reduces the efficacy of oral contraceptives?
- A. Griseofulvin (Correct Answer)
- B. Disulfiram
- C. Erythromycin
- D. Cimetidine
Explanation: ***Griseofulvin*** - **Griseofulvin** is an antifungal agent known to induce liver enzymes, specifically the **cytochrome P450 system**. - Enzyme induction accelerates the metabolism and clearance of **oral contraceptives**, leading to lower plasma concentrations and reduced efficacy. *Erythromycin* - **Erythromycin** is a macrolide antibiotic that typically inhibits liver enzymes rather than inducing them. - While it can interfere with the metabolism of some drugs, it usually **increases** rather than decreases the plasma levels of co-administered medications, and is not known to reduce oral contraceptive efficacy. *Disulfiram* - **Disulfiram** is used to treat chronic alcoholism and inhibits aldehyde dehydrogenase. - It does not significantly interact with the metabolism of **oral contraceptives** via the cytochrome P450 system or other mechanisms that would reduce their efficacy. *Cimetidine* - **Cimetidine** is an H2 receptor antagonist that is known to inhibit cytochrome P450 enzymes. - This inhibition would likely **increase** the plasma concentration of drugs metabolized by these enzymes, such as oral contraceptives, rather than reducing their efficacy.
Question 653: Visual field monitoring is important before starting which of the following drugs for epilepsy treatment?
- A. Vigabatrin (Correct Answer)
- B. Topiramate
- C. Valproic acid
- D. Carbamazepine
Explanation: ***Vigabatrin*** - **Vigabatrin** is known to cause **irreversible concentric visual field constriction** (peripheral vision loss) due to retinal toxicity. - Regular **ophthalmological monitoring**, including **visual field testing**, is crucial before and during treatment to detect and manage this adverse effect early. *Topiramate* - Topiramate can cause **acute angle-closure glaucoma** and **myopia**, which affect vision, but regular visual field monitoring is not a primary requirement for this specific side effect. - Its main concerns often relate to cognitive side effects and kidney stones, rather than progressive visual field loss requiring baseline and ongoing field testing. *Valproic acid* - Valproic acid is not typically associated with specific visual field defects requiring routine monitoring. - Its major side effects often involve **hepatotoxicity**, **pancreatitis**, and **teratogenicity**. *Carbamazepine* - Carbamazepine's notable side effects include **aplastic anemia**, **hyponatremia**, and **Stevens-Johnson syndrome**. - While it can cause some ocular side effects like **diplopia** or **nystagmus**, it does not typically lead to the progressive and irreversible visual field constriction seen with vigabatrin, which necessitates strict monitoring.
Question 654: Which of the following is a tricyclic antidepressant?
- A. Fluoxetine
- B. Citalopram
- C. Doxepin (Correct Answer)
- D. Venlafaxine
Explanation: ***Doxepin*** - **Doxepin** is a **tricyclic antidepressant (TCA)** that inhibits the reuptake of **serotonin** and **norepinephrine**, and also has significant **histaminergic** and **cholinergic** blocking effects. - TCAs, including doxepin, are commonly used for treating **depression**, **anxiety**, and certain pain conditions. *Venlafaxine* - **Venlafaxine** is a **serotonin-norepinephrine reuptake inhibitor (SNRI)**, not a tricyclic antidepressant. - SNRIs selectively block the reuptake of both **serotonin** and **norepinephrine**, but lack the broad receptor affinity of TCAs. *Fluoxetine* - **Fluoxetine** is a **selective serotonin reuptake inhibitor (SSRI)**, which specifically targets serotonin reuptake. - SSRIs are generally considered a first-line treatment for depression due to a more favorable side effect profile compared to TCAs. *Citalopram* - **Citalopram** is also a **selective serotonin reuptake inhibitor (SSRI)**, much like fluoxetine. - It works by increasing the levels of **serotonin** in the brain by blocking its reuptake, differentiating it from tricyclic antidepressants.
Question 655: What is the drug of choice for pheochromocytoma?
- A. Propranolol
- B. Phenoxybenzamine (Correct Answer)
- C. Prazosin
- D. Nitroprusside
Explanation: ***Phenoxybenzamine*** - This is an **irreversible, non-selective alpha-adrenergic blocker**, which is the drug of choice for preparing patients for surgical removal of a pheochromocytoma. - It effectively controls **hypertension** by blocking the effects of catecholamines on blood vessels, preventing a hypertensive crisis during surgery. *Propranolol* - **Beta-blockers** like propranolol should **not be used as monotherapy** in pheochromocytoma because blocking beta-2 receptors without prior alpha blockade can lead to unopposed alpha-adrenergic vasoconstriction and precipitate a **hypertensive crisis**. - It can be added **after adequate alpha-blockade** to control tachycardia. *Prazosin* - Prazosin is a **reversible, selective alpha-1 adrenergic blocker**, which is not preferred over phenoxybenzamine due to its shorter duration of action and reversibility. - While it can lower blood pressure, its efficacy in preventing hypertensive crises during surgery for pheochromocytoma is **less robust** compared to phenoxybenzamine. *Nitroprusside* - Sodium nitroprusside is a **potent vasodilator** often used for **hypertensive emergencies**, but it is not the drug of choice for long-term management or preoperative preparation in pheochromocytoma. - Its use in pheochromocytoma is typically reserved for **acute hypertensive crises** when other agents are insufficient, rather than initial management.
Question 656: What is the mechanism of action of Warfarin?
- A. Inhibition of Vitamin K epoxide reductase (Correct Answer)
- B. Inhibition of gamma glutamyl carboxylase
- C. Activation of Vitamin K epoxide reductase
- D. Activation of gamma glutamyl carboxylase
Explanation: ***Inhibition of Vitamin K epoxide reductase*** - Warfarin blocks **Vitamin K epoxide reductase (VKORC1)** [1, 2, 3], an enzyme essential for recycling oxidized vitamin K into its active reduced form [1, 3]. - This reduction prevents the activation of **vitamin K-dependent clotting factors** (II, VII, IX, X), leading to anticoagulation [1, 3]. *Inhibition of gamma glutamyl carboxylase* - **Gamma-glutamyl carboxylase** uses reduced vitamin K as a cofactor to carboxylate specific glutamic acid residues on clotting factors [1, 3]. - While essential for clotting factor activation, this enzyme itself is **not directly inhibited by warfarin** [1, 3]. *Activation of Vitamin K epoxide reductase* - Activating **VKORC1** would increase the production of reduced vitamin K, thereby **promoting coagulation** rather than inhibiting it [1, 2]. - This is the opposite of warfarin's intended therapeutic effect. *Activation of gamma glutamyl carboxylase* - Activating **gamma-glutamyl carboxylase** would enhance the carboxylation and activation of **clotting factors**, leading to procoagulant effects [1, 3]. - This mechanism contradicts warfarin's role as an **anticoagulant**.
Question 657: Which of the following is a classic tricyclic antidepressant (TCA) commonly used as the prototype for the class?
- A. Amitriptyline (Correct Answer)
- B. Citalopram
- C. Venlafaxine
- D. Nortriptyline
Explanation: ***Amitriptyline*** - **Amitriptyline** is a classic tricyclic antidepressant (TCA) and is widely recognized for its use in treating depression, neuropathic pain, and migraine prophylaxis. Its characteristic side effect profile, including **anticholinergic effects** and **sedation**, is well-known. - It is one of the **oldest and most frequently prescribed TCAs**, making it a common reference point in pharmacology and clinical practice. *Citalopram* - **Citalopram** is an **SSRI** (selective serotonin reuptake inhibitor), not a TCA. It works by selectively inhibiting the reuptake of serotonin. - It has a different side effect profile compared to TCAs, generally with fewer anticholinergic and cardiovascular effects. *Venlafaxine* - **Venlafaxine** is an **SNRI** (serotonin-norepinephrine reuptake inhibitor), not a TCA. It inhibits the reuptake of both serotonin and norepinephrine. - It has efficacy in treating depression and anxiety disorders, but its mechanism of action is distinct from TCAs. *Nortriptyline* - **Nortriptyline** is indeed a TCA, specifically a **secondary amine TCA**, which is an active metabolite of amitriptyline. - While it is a TCA, amitriptyline is generally more broadly recognized and used as the prototype for the class, with nortriptyline often being highlighted for its slightly better tolerability profile (e.g., less sedation, less orthostatic hypotension) compared to tertiary amine TCAs like amitriptyline.