NEET-PG 2012 Practice Questions

Q: What is the concentration of type 3 virus in the trivalent oral polio vaccine?

600,000 TCID 50. ***600,000 TCID 50*** - The **trivalent oral polio vaccine (tOPV)** traditionally contained specific concentrations of each serotype: **type 1 (1,000,000 TCID50/dose)**, **type 2 (100,000 TCID50/dose)**, and **type 3 (600,000 TCID50/dose)**. - Type 3 poliovirus requires a **higher concentration (600,000 TCID50)** compared to type 2 to achieve adequate immunogenicity and protection. - The **World Health Organization (WHO)** established these specific formulations for tOPV to ensure optimal efficacy and safety for each serotype. *100,000 TCID 50* - This is the concentration of **type 2 poliovirus** in tOPV, not type 3. - Due to the **global eradication of wild poliovirus type 2** by 2015, tOPV was replaced with bivalent OPV (bOPV) containing only types 1 and 3 in routine immunization programs. *400,000 TCID 50* - This concentration does not correspond to any standard poliovirus serotype in the traditional trivalent oral polio vaccine. - This value falls between type 2 (100,000) and type 3 (600,000) concentrations but is not used. *300,000 TCID 50* - This concentration is not the standard for any poliovirus serotype in the traditional trivalent oral polio vaccine. - Each serotype has a **distinct, empirically determined concentration** to achieve optimal immunity while minimizing adverse effects.

Q: Multi-purpose worker scheme in India was introduced following the recommendation of ?

Kartar Singh Committee. ***Kartar Singh Committee*** - The **Kartar Singh Committee** (1973) recommended the implementation of the **multi-purpose worker scheme** in India. - This scheme aimed to integrate several health services at the grassroots level through a single health worker. *Srivastava Committee* - The **Srivastava Committee** (1975) focused on the creation of a **Medical and Health Education Commission** to reform medical education. - It did not specifically recommend the multi-purpose worker scheme. *Bhore Committee* - The **Bhore Committee** (1946), also known as the Health Survey and Development Committee, recommended a comprehensive health service with an emphasis on preventive and curative care. - It laid conceptual groundwork for primary healthcare but did not specifically propose the multi-purpose worker scheme, which came much later. *Chadha Committee* - The **Chadha Committee** (1963) reviewed India's health infrastructure and medical education. - It focused on health center development and medical college expansion, not the multi-purpose worker scheme.

Q: Which of the following fields is primarily associated with the Hardy-Weinberg law?

Population genetics. ***Population genetics*** - The **Hardy-Weinberg law** is a fundamental principle in **population genetics** that describes allele and genotype frequencies in a population. - It establishes a baseline for hypothetical populations that are not evolving, allowing for the study of deviations caused by evolutionary forces. - The equation (p² + 2pq + q² = 1) predicts genotype frequencies from allele frequencies under specific conditions. *Health economics* - **Health economics** applies economic theories to the healthcare sector, focusing on efficiency, effectiveness, and value. - This field is concerned with resource allocation, financing, and policy in health, not genetic frequencies. *Social medicine* - **Social medicine** investigates the social and environmental determinants of health and disease. - It focuses on public health, health disparities, and the societal factors influencing well-being, which is distinct from genetic population dynamics. *Epidemiology* - **Epidemiology** studies the distribution and determinants of disease in populations. - While both fields study populations, epidemiology focuses on disease patterns and risk factors, not genetic equilibrium or allele frequencies.

Q: What percentage of oral cancer cases is attributed to tobacco use?

70% of cases. ***90%*** - Nicotine is a significant contributor to **oral cancer**, with studies indicating it is responsible for about **90%** of cases [1]. - Its carcinogenic effects are amplified when combined with other risk factors such as **tobacco** and **alcohol** use [1]. *40%* - This percentage underestimates nicotine's role in oral cancer development, which is much higher. - Key studies suggest that the impact of nicotine alone is much greater than **40%**, highlighting its pivotal role in carcinogenesis. *60%* - This estimate also falls short, as the consensus in oncology is that nicotine significantly contributes even beyond **60%**. - Oral cancer risk is further elevated when nicotine is consumed in conjunction with other **carcinogens** [1], rather than just being limited to a single contribution. *10%* - This figure drastically underrepresents nicotine's involvement, as it is a major causative agent in oral cancer. - The **10%** suggestion implies minimal risk, contradicting clinical evidence that strongly supports a far greater role for nicotine. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 738-739.

Q: Which type of vaccine is used for chicken pox?

Live vaccine. ***Live vaccine*** - The chickenpox vaccine (Varicella vaccine) is a **live-attenuated vaccine**, meaning it contains a weakened form of the **Varicella-zoster virus** (Oka strain). - This weakened virus can still replicate in the body, stimulating a strong and long-lasting immune response similar to natural infection but without causing severe disease. *Killed vaccine* - **Killed (inactivated) vaccines** use viruses or bacteria that have been inactivated through heat or chemicals, making them unable to replicate. - While effective for some diseases (e.g., inactivated polio, influenza), they typically require **multiple doses** and might provide less durable immunity compared to live vaccines. *Conjugated vaccine* - **Conjugated vaccines** are designed to improve the immune response to polysaccharide antigens (e.g., bacterial capsules) by linking them to a carrier protein. - This technology is primarily used for **bacterial infections** like *Haemophilus influenzae* type b (Hib) or pneumococcal disease, not viral illnesses like chickenpox. *Toxoid vaccine* - **Toxoid vaccines** contain inactivated bacterial toxins (toxoids) rather than the whole organism. - Examples include **tetanus and diphtheria vaccines**, which protect against diseases caused by bacterial toxins, not viral infections like chickenpox.

Q: Which antibiotic is Actinomycosis sensitive to?

Penicillin. ***Penicillin*** - **Penicillin** is the **antibiotic of choice** for treating Actinomycosis due to the organism's high sensitivity. - Treatment typically involves a **long course** of high-dose penicillin for several months. *Streptomycin* - **Streptomycin** is an **aminoglycoside antibiotic** primarily used for **tuberculosis** and some gram-negative bacterial infections. - It is **not effective** against Actinomyces species. *Nystatin* - **Nystatin** is an **antifungal medication** used to treat **yeast infections**, particularly Candida. - It has **no antibacterial activity** and thus no role in treating Actinomycosis. *Doxycycline* - While **doxycycline** can be used as an **alternative** in patients allergic to penicillin, it is **not the primary choice**. - Its effectiveness is generally less pronounced than penicillin, and it's reserved for second-line treatment.

Q: Botulism is most commonly due to -

Home-canned vegetables. ***Home-canned vegetables*** - **Home-canned vegetables** are the **most common** source of botulism, particularly improperly processed low-acid vegetables like beans, corn, and asparagus - *Clostridium botulinum* spores survive inadequate heat treatment and germinate in the **anaerobic, low-acid environment** of improperly canned foods - The **lack of sufficient heat sterilization** (pressure canning at 121°C/250°F is required) allows spore survival and subsequent toxin production - Most foodborne botulism outbreaks are traced to **home-canned vegetables** rather than commercially processed foods *Meat* - While improperly preserved meats can cause botulism, they are **not the most common source** in epidemiological data - Commercial meat processing standards and refrigeration significantly reduce this risk - Meat-associated botulism is more common in certain cultural practices involving fermented or preserved meats *Egg* - **Eggs** are not associated with botulism as they do not provide the anaerobic environment necessary for *Clostridium botulinum* toxin production - Eggs are more commonly linked to **Salmonella infections** if improperly handled or undercooked *Milk* - **Milk** and dairy products are not typical sources of botulism - **Pasteurization** and refrigeration prevent conditions favorable for *C. botulinum* growth - Dairy products are more associated with **Listeria** or **Campylobacter** if contaminated

Q: In which condition is the swinging light test positive?

Optic neuritis. ***Optic neuritis*** - The swinging light test (also known as the **Marcus Gunn pupil** or relative afferent pupillary defect, RAPD) is positive when there is a significant **asymmetry in the afferent visual pathway** between the two eyes. - In optic neuritis, the **optic nerve** is inflamed and demyelinated, impairing the transmission of light signals to the brain, which leads to a paradoxical pupillary dilation when the light is swung from the unaffected to the affected eye. *Conjunctivitis* - This is an **inflammation of the conjunctiva**, the membrane lining the eyelid and sclera, which primarily affects the ocular surface. - It does not involve the optic nerve or afferent pupillary pathways, so the swinging light test would be **negative**. *Glaucoma* - Glaucoma is a condition characterized by **progressive optic nerve damage**, often associated with elevated intraocular pressure, leading to peripheral vision loss. - While it causes optic neuropathy, a positive swinging light test is typically seen only in **severe, asymmetric cases** and is not its primary diagnostic feature. *Keratoconus* - This is a non-inflammatory eye condition in which the normally round dome-shaped cornea **thins and bulges outward into a cone-like shape**. - It affects the **cornea's shape and vision quality**, but not the optic nerve or the afferent pupillary reflex pathway, thus the swinging light test would be negative.

Q: Finasteride is classified as a:

5-alpha reductase inhibitor. ### ***5-alpha reductase inhibitor*** - **Finasteride** specifically inhibits the enzyme **5-alpha reductase**, preventing the conversion of **testosterone** to **dihydrotestosterone (DHT)** [2], [4]. - This reduction in DHT is clinically useful for treating conditions like **benign prostatic hyperplasia (BPH)** and **androgenetic alopecia** [4]. ### *Phosphodiesterase inhibitor* - **Phosphodiesterase inhibitors** (e.g., sildenafil) typically work by increasing levels of **cyclic GMP**, leading to **vasodilation** and are used for **erectile dysfunction** [3]. - Their mechanism of action is distinct from finasteride's effect on **hormone metabolism**. ### *Alpha-1 blocker* - **Alpha-1 blockers** (e.g., tamsulosin) primarily relax **smooth muscle** in the prostate and bladder neck, improving **urine flow** in BPH [3], [5]. - They act on **adrenergic receptors** and do not affect **hormone synthesis** or **metabolism** [3]. ### *Androgen receptor antagonist* - **Androgen receptor antagonists** (e.g., flutamide) directly block the binding of **androgens** (like testosterone and DHT) to their receptors [1], [4]. - While they also affect androgen action, their mechanism is different from finasteride's **enzyme inhibition** [4].

Q: Which of the following is NOT a mechanism of action of theophylline in bronchial asthma?

Beta-2 receptor stimulation. ***Beta-2 receptor stimulation*** - Theophylline is a **non-selective phosphodiesterase inhibitor** and an **adenosine receptor antagonist**, but it does not directly stimulate beta-2 receptors. - **Beta-2 receptor agonists** like salbutamol or formoterol are the medications that work by stimulating these receptors to cause bronchodilation. *Phosphodiesterase inhibition* - Theophylline inhibits **phosphodiesterase enzymes**, leading to an increase in intracellular **cAMP** levels. - This increase in **cAMP** promotes bronchodilation by relaxing airway smooth muscle. *Adenosine receptor antagonism* - Theophylline acts as an antagonist at **adenosine receptors**, particularly A1 and A2B. - Antagonism of adenosine receptors can reduce bronchoconstriction and inflammatory mediator release, contributing to its anti-asthmatic effects. *Increased histone deacetylation* - Theophylline, particularly at lower concentrations, increases the activity of **histone deacetylase (HDAC)**. - This action helps to **repress inflammatory gene expression**, which is a unique anti-inflammatory mechanism separate from its bronchodilatory effects.

Question 1

What is the concentration of type 3 virus in the trivalent oral polio vaccine?

Accepted Answer

600,000 TCID 50

Answer

400,000 TCID 50

Answer

100,000 TCID 50

Answer

300,000 TCID 50

Question 2

Multi-purpose worker scheme in India was introduced following the recommendation of ?

Accepted Answer

Kartar Singh Committee

Answer

Srivastava Committee

Answer

Bhore Committee

Answer

Chadha Committee

Question 3

Which of the following fields is primarily associated with the Hardy-Weinberg law?

Accepted Answer

Population genetics

Answer

Health economics

Answer

Social medicine

Answer

Epidemiology

Question 4

What percentage of oral cancer cases is attributed to tobacco use?

Accepted Answer

70% of cases

Answer

60% of cases

Answer

10% of cases

Answer

40% of cases

Question 5

Which type of vaccine is used for chicken pox?

Accepted Answer

Live vaccine

Answer

Killed vaccine

Answer

Conjugated vaccine

Answer

Toxoid vaccine

Question 6

Which antibiotic is Actinomycosis sensitive to?

Accepted Answer

Penicillin

Answer

Streptomycin

Answer

Nystatin

Answer

Doxycycline

Question 7

Botulism is most commonly due to -

Accepted Answer

Home-canned vegetables

Answer

Egg

Answer

Milk

Answer

Meat

Question 8

In which condition is the swinging light test positive?

Accepted Answer

Optic neuritis

Answer

Conjunctivitis

Answer

Glaucoma

Answer

Keratoconus

Question 9

Finasteride is classified as a:

Accepted Answer

5-alpha reductase inhibitor

Answer

Phosphodiesterase inhibitor

Answer

Alpha-1 blocker

Answer

Androgen receptor antagonist

Question 10

Which of the following is NOT a mechanism of action of theophylline in bronchial asthma?

Accepted Answer

Beta-2 receptor stimulation

Answer

Adenosine receptor antagonism

Answer

Increased histone deacetylation

Answer

Phosphodiesterase inhibition

NEET-PG 2012

Community Medicine

Dental

Microbiology

Ophthalmology

Pharmacology