NEET-PG 2013 Practice Questions

Q: Clinical effect of vitamin D is reduced by ?

Simultaneous ingestion of phytates. ***Simultaneous ingestion of phytates*** - **Phytates (phytic acid)** found in whole grains, nuts, seeds, and legumes can **reduce the clinical effect of vitamin D** through multiple mechanisms - Phytates **chelate calcium** and form insoluble calcium-phytate complexes, reducing calcium absorption - Since **vitamin D and calcium metabolism are closely linked**, impaired calcium absorption indirectly reduces vitamin D efficacy - Phytates can also **directly bind to vitamin D** in the gastrointestinal tract, reducing its bioavailability - Studies show that **high phytate intake increases vitamin D requirements** and can impair vitamin D status *Simultaneous ingestion of lactose* - Lactose does **not reduce** vitamin D absorption or efficacy - In fact, **dairy products are commonly fortified** with vitamin D, and the presence of lactose does not interfere with its beneficial effects - Lactose may actually **enhance calcium absorption**, which works synergistically with vitamin D *Acidic environment* - Vitamin D is a **fat-soluble vitamin** absorbed primarily in the small intestine - An acidic environment (stomach acid) is **not known to inhibit** vitamin D absorption - The absorption process occurs in the **alkaline environment of the small intestine** where fat-soluble vitamins are absorbed with dietary fats *None of the options* - This is **incorrect** as phytates do reduce the clinical effect of vitamin D through calcium chelation and direct binding mechanisms

Q: In psychiatric assessment, which term refers to a temporary and subjective judgment or viewpoint expressed by a patient regarding their condition or treatment?

Opinion. ***Opinion*** - An **opinion** is a transient, personal judgment or viewpoint that a patient expresses, often based on their current understanding or feelings. - It does not necessarily reflect deep-seated convictions but rather a momentary take on their condition or treatment. *Belief* - A **belief** is a more deeply held and enduring conviction that a patient holds, often influencing their perspective and decision-making over time. - Unlike an opinion, a belief is less likely to change quickly and can be foundational to a patient's understanding of their health or illness. *Practice* - **Practice** refers to the regular implementation of specific behaviors, routines, or strategies, especially those related to treatment or self-care. - It describes actions rather than a patient's thoughts, judgments, or viewpoints. *Attitude* - An **attitude** is a more stable predisposition or mental stance towards an object, person, or situation, encompassing thoughts, feelings, and behavioral intentions. - While it can influence opinions, an attitude is a broader and more consistent concept than a temporary judgment.

Q: Which of the following viral diseases is least commonly reported in India?

Lassa fever. ***Lassa fever*** - **Lassa fever** is endemic to West Africa, with the **multimammate rat** being its primary reservoir. - Cases of Lassa fever are **extremely rare** in India, primarily limited to travel-related instances due to the geographical distribution of the disease and its vector. *Japanese B encephalitis* - **Japanese B encephalitis (JBE)** is a significant public health concern in India, particularly in endemic regions. - It is a mosquito-borne viral disease, and **vaccination programs** are ongoing to control its spread. *KFD* - **Kyasanur Forest Disease (KFD)** is an endemic viral hemorrhagic fever primarily found in the **Karnataka state of India**. - It is transmitted by **ticks**, making it a regionally significant but recognized viral disease within India. *Dengue* - **Dengue** is one of the most commonly reported and widespread viral diseases in India. - It is a **mosquito-borne** illness with frequent outbreaks occurring across various parts of the country.

Q: Trophozoites in stool are characteristically seen in which of the following conditions?

**Note:** This question has significant issues. Trophozoites in stool are characteristically seen in **protozoal infections** such as *Entamoeba histolytica* (amoebiasis), *Giardia lamblia*, or *Balantidium coli* [1][2] - none of which are listed as options. ***None of the given options is medically accurate*** for characteristic trophozoites in stool. However, if forced to choose from these options: *Ascariasis* - **Ascariasis** is caused by the nematode *Ascaris lumbricoides* - Diagnosis is by identifying **ova (eggs)** in stool, not trophozoites - Trophozoites are protozoal forms, not associated with helminthic infections [2] *Strongyloidiasis* - Caused by *Strongyloides stercoralis* (nematode) - Typically diagnosed by finding **rhabditiform or filariform larvae** in stool - Not characterized by trophozoites in routine stool examination *Eosinophilic gastroenteritis* - Inflammatory condition with **eosinophilic infiltration** of GI tract - Not a parasitic infection - No trophozoites present - diagnosis is by endoscopic biopsy showing eosinophils *Allergic colitis* - Inflammatory condition related to **food allergies** (common in infants) - Presents with blood and mucus in stool with eosinophilia - Not an infectious process - no trophozoites present **Clinical Pearl:** Trophozoites (motile feeding stage of protozoa) in stool are diagnostic of **acute intestinal protozoal infections** like amoebiasis or giardiasis, where they must be identified in fresh, warm stool samples as they rapidly deteriorate [1][2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Alimentary System Disease, pp. 364-365. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Gastrointestinal Tract, pp. 801-802.

Q: Which of the following statements about malaria transmission is correct?

Individuals harboring gametocytes can transmit malaria.. ***Individuals harboring gametocytes can transmit malaria.*** - **Gametocytes** are the sexual stage of the malaria parasite that circulate in the human bloodstream and are infectious to mosquitos. - When an *Anopheles* mosquito feeds on an infected human, it ingests these gametocytes, allowing the parasite's life cycle to continue in the mosquito vector, leading to transmission. *P. vivax always completely fills the infected RBC with schizonts.* - While *P. vivax* does infect **reticulocytes** (young RBCs) and can enlarge them, the **schizonts** typically occupy a significant portion but not always completely fill the host cell. - The infected RBCs are often enlarged to about 1.5 to 2 times their normal size and contain numerous **Schüffner's dots**. *Malaria can only be transmitted through blood transfusions.* - The primary mode of malaria transmission is through the bite of an **infected female *Anopheles* mosquito**. - While **blood transfusions** can transmit malaria, it is a less common and secondary route compared to vector-borne transmission. *All stages of P. falciparum are commonly seen in peripheral blood smears.* - In *P. falciparum* infections, only the **ring forms** and **gametocytes** are commonly observed in the peripheral blood smear. - The more mature asexual stages (trophozoites and schizonts) typically sequester in the capillaries of internal organs, where they are not readily visible in peripheral circulation.

Q: What is the mechanism of action of Warfarin?

Inhibition of Vitamin K epoxide reductase. ***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**.

Q: Which of the following drugs inhibits the activation of plasminogen?

Aminocaproic acid. ***Correct Option: Aminocaproic acid*** - **Aminocaproic acid** is an antifibrinolytic drug that acts by competitively inhibiting the activation of **plasminogen** to plasmin. - By preventing the formation of plasmin, it stabilizes blood clots and is used to treat excessive bleeding. *Incorrect Option: Streptokinase* - **Streptokinase** is a **thrombolytic agent** that forms a complex with plasminogen, converting uncomplexed plasminogen into plasmin. - This action promotes the degradation of fibrin clots, making it a **fibrinolytic drug**, not an inhibitor of plasminogen activation. *Incorrect Option: Reteplase* - **Reteplase** is a **recombinant tissue plasminogen activator (tPA)** that directly converts plasminogen to plasmin. - This drug actively promotes **fibrinolysis** and clot breakdown, making it a thrombolytic agent. *Incorrect Option: Clopidogrel* - **Clopidogrel** is an **antiplatelet drug** that inhibits platelet aggregation by irreversibly blocking the P2Y12 adenosine diphosphate (ADP) receptor on platelets. - Its mechanism of action is focused on **platelet function**, not on the plasminogen-plasmin system.

Q: Drug of choice for familial hypercholesterolemia?

Lovastatin. ***Lovastatin*** - **Statins** (HMG-CoA reductase inhibitors) are the **first-line therapy** for familial hypercholesterolemia as they effectively lower **LDL cholesterol** levels by inhibiting cholesterol synthesis [1]. - While other agents can be used adjunctively, statins like lovastatin are the cornerstone for managing this genetic condition [2]. *Nicotinic acid* - **Nicotinic acid** (niacin) primarily lowers **triglycerides** and increases **HDL cholesterol**, but it is less potent than statins for reducing LDL-C, especially in familial hypercholesterolemia [1]. - Its use is often limited by significant **side effects** like flushing. *Cholestyramine* - **Cholestyramine** is a **bile acid sequestrant** that binds to bile acids in the intestine, preventing their reabsorption and mildly lowering LDL cholesterol. - It is less effective than statins and often causes **gastrointestinal side effects** such as constipation and bloating. *Gemfibrozil* - **Gemfibrozil** is a **fibrate**, primarily used to lower **triglyceride levels** and increase HDL cholesterol. - It has minimal impact on LDL cholesterol compared to statins and is not the primary treatment for familial hypercholesterolemia [2].

Q: Drug that binds bile acids in the intestine and prevents their return to liver via the enterohepatic circulation?

Cholestyramine. ***Cholestyramine*** - **Cholestyramine** is a **bile acid-binding resin** that sequesters bile acids in the intestine, preventing their reabsorption. - This interruption of the **enterohepatic circulation** leads to increased synthesis of new bile acids from cholesterol in the liver, thus lowering plasma LDL cholesterol. *Niacin* - **Niacin (nicotinic acid)** reduces the hepatic synthesis and secretion of **VLDL**, which in turn lowers LDL and triglyceride levels. - It works primarily through mechanisms related to fat metabolism in the liver and adipose tissue, not direct bile acid binding in the intestine. *Fenofibrate* - **Fenofibrate** is a **PPAR-α agonist** that primarily reduces triglyceride levels by increasing fatty acid oxidation and lipoprotein lipase activity, and secondarily increases HDL. - Its main action is on lipid metabolism in the liver and peripheral tissues, not by binding bile acids in the gut. *Gugulipid* - **Gugulipid** is a phytosterol derived from the guggul tree, sometimes used in traditional medicine for cholesterol management. - Its purported mechanism involves increasing **bile acid excretion** and inhibiting cholesterol biosynthesis, but it does not directly bind bile acids in the same manner as resins like cholestyramine.

Question 1

Clinical effect of vitamin D is reduced by ?

Accepted Answer

Simultaneous ingestion of phytates

Answer

Simultaneous ingestion of lactose

Answer

None of the options

Answer

Acidic environment

Question 2

In psychiatric assessment, which term refers to a temporary and subjective judgment or viewpoint expressed by a patient regarding their condition or treatment?

Accepted Answer

Opinion

Answer

Belief

Answer

Practice

Answer

Attitude

Question 3

Which of the following viral diseases is least commonly reported in India?

Accepted Answer

Lassa fever

Answer

Japanese B encephalitis

Answer

KFD

Answer

Dengue

Question 4

Trophozoites in stool are characteristically seen in which of the following conditions?

Answer

Ascariasis

Answer

Strongyloidiasis

Answer

Allergic colitis

Answer

Eosinophilic gastroenteritis

Question 5

Which of the following statements about malaria transmission is correct?

Accepted Answer

Individuals harboring gametocytes can transmit malaria.

Answer

P. vivax always completely fills the infected RBC with schizonts.

Answer

Malaria can only be transmitted through blood transfusions.

Answer

All stages of P. falciparum are commonly seen in peripheral blood smears.

Question 6

What is the mechanism of action of Warfarin?

Accepted Answer

Inhibition of Vitamin K epoxide reductase

Answer

Inhibition of gamma glutamyl carboxylase

Answer

Activation of Vitamin K epoxide reductase

Answer

Activation of gamma glutamyl carboxylase

Question 7

Which of the following drugs inhibits the activation of plasminogen?

Accepted Answer

Aminocaproic acid

Answer

Streptokinase

Answer

Reteplase

Answer

Clopidogrel

Question 8

Which of the following statements about hypolipidemic drugs is false?

Accepted Answer

Cholesterol reducing drugs are contraindicated in child less than 8 years

Answer

Gemfibrozil causes myopathy

Answer

Gemfibrozil can increase myopathy caused by statins

Answer

Lovastatin can cause hepatic dysfunction

Question 9

Drug of choice for familial hypercholesterolemia?

Accepted Answer

Lovastatin

Answer

Nicotinic acid

Answer

Cholestyramine

Answer

Gemfibrozil

Question 10

Drug that binds bile acids in the intestine and prevents their return to liver via the enterohepatic circulation?

Accepted Answer

Cholestyramine

Answer

Niacin

Answer

Fenofibrate

Answer

Gugulipid

NEET-PG 2013

Biochemistry

Community Medicine

Microbiology

Pharmacology