INI-CET 2022 Practice Questions

Q: What is the volume of the prostate in normal adult males?

20cc. ***20cc*** - The normal prostate volume in adult males is typically **20 cubic centimeters (cc)** or grams, which is approximately the size of a walnut. - This volume is generally used as a baseline when assessing for conditions like **benign prostatic hyperplasia (BPH)** or prostate cancer, where an enlarged prostate is a key indicator [1]. *50cc* - A prostate volume of 50cc is considered **enlarged** and is often indicative of **benign prostatic hyperplasia (BPH)**, especially in older men [1]. - This volume would lead to symptoms of **lower urinary tract symptoms (LUTS)**, such as frequent urination or difficulty voiding, which are not characteristic of a normal prostate [1]. *75cc* - A prostate volume of 75cc represents a **significantly enlarged prostate**, well beyond the normal range. - Such a size would almost certainly be associated with **moderate to severe LUTS** and likely require medical intervention for BPH. *100cc* - A 100cc prostate is considered a **markedly enlarged prostate**, typically resulting in severe **urinary obstruction** and significant impact on quality of life. - This volume is far from normal and would usually necessitate treatment for **benign prostatic hyperplasia (BPH)**.

Q: Cyclooxygenase plays a role in which pathway?

Prostaglandin. ***Prostaglandin*** - **Cyclooxygenase (COX)** enzymes specifically catalyze the conversion of **arachidonic acid** into **prostaglandins**, **prostacyclins**, and **thromboxanes**. - This pathway is crucial for mediating **inflammation**, **fever**, and **pain** responses in the body. *Leukotriene* - **Leukotrienes** are synthesized via the **lipoxygenase** pathway, not the cyclooxygenase pathway. - They are primarily involved in **allergic reactions** and **asthma**, causing bronchoconstriction and increased vascular permeability. *Vitamin K* - **Vitamin K** is a fat-soluble vitamin essential for the synthesis of **blood clotting factors** and does not involve cyclooxygenase enzymes. - It acts as a cofactor for the enzyme **gamma-glutamyl carboxylase**. *Krebs cycle* - The **Krebs cycle (citric acid cycle)** is a central metabolic pathway for **cellular respiration**, producing ATP, NADH, and FADH2. - It takes place in the **mitochondria** and is involved in the breakdown of carbohydrates, fats, and proteins for energy, unrelated to cyclooxygenase.

Q: Which of the following statements are true about familial adenomatous polyposis? 1. It is autosomal recessive 2. If not treated, 100% of the cases progress to adenocarcinoma colon. 3. It is associated with a gene mutation in KRAS 4. It is associated with congenital hypertrophy of the retinal pigment epithelium.

2 and 4. ***2 and 4*** - Without treatment, **familial adenomatous polyposis (FAP)** leads to colorectal **adenocarcinoma** in 100% of cases, due to the accumulation of numerous adenomatous polyps throughout the colon. - FAP is strongly associated with **congenital hypertrophy of the retinal pigment epithelium (CHRPE)**, which can be an early diagnostic marker [1]. *None of the options* - This statement is incorrect because FAP does indeed involve the progression to adenocarcinoma and is associated with CHRPE. - The combination of these two true statements makes this option invalid. *1 and 4* - FAP is inherited in an **autosomal dominant** manner, not autosomal recessive [1]. - While statement 4 (association with CHRPE) is true, statement 1 being false makes this option incorrect. *2 and 3* - Although statement 2 (100% progression to adenocarcinoma) is true, statement 3 is incorrect. - FAP is primarily caused by mutations in the **APC gene**, not the KRAS gene [1]. KRAS is more commonly associated with sporadic colorectal cancer progression rather than FAP.

Q: The following is a histopathological image of thyroid pathology. What is the diagnosis?

Medullary carcinoma of thyroid. ***Medullary carcinoma of thyroid*** - This image shows sheets and nests of **polygonal to spindle-shaped cells**, which are characteristic of medullary thyroid carcinoma, especially when mixed with an **amyloid stroma** (seen as amorphous eosinophilic material) [2]. - The presence of **neuroendocrine features** and the production of **calcitonin** are hallmarks of these C-cell tumors [1], [2]. *Papillary carcinoma of thyroid* - Characterized by **papillary architecture**, **ground-glass (Orphan Annie eye) nuclei**, nuclear grooves, and intranuclear cytoplasmic inclusions. - These features are not prominently seen in the provided image. *Follicular carcinoma of thyroid* - Defined by an invasive growth pattern of **well-differentiated follicular cells** forming follicles, with either capsular or vascular invasion [2]. - The image does not show classic follicular architectural patterns or clear evidence of invasion in the absence of a capsule. *Anaplastic carcinoma of thyroid* - This is a highly aggressive and undifferentiated tumor with **marked pleomorphism**, bizarre giant cells, and high mitotic activity [2]. - While there is some pleomorphism, the overall pattern and cellular morphology in the image are more consistent with medullary carcinoma than the extreme anaplasia. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1102-1103. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 428-431.

Q: A 10-year-old boy presented with fatigue. Investigations revealed: Hemoglobin, 9 g/dL; MCV, 60 fL; MCH, 20 pg; and serum ferritin, 185 µg/L. The TLC was elevated and showed predominant lymphocytes and neutrophils. What is the likely diagnosis in this patient? **Normal values:** - Serum ferritin: 50-150 µg/L

Beta thalassemia trait. ***Beta thalassemia trait*** - The combination of **microcytic hypochromic anemia** (low MCV, MCH) with **normal to elevated ferritin** (185 µg/L is above the normal range of 50-150 µg/L) is highly suggestive of **beta thalassemia trait**, as iron stores are typically adequate or increased. - An elevated TLC with predominant lymphocytes and neutrophils is nonspecific but does not rule out thalassemia, as secondary infections or inflammatory processes can occur. *Anemia of chronic disease* - While anemia of chronic disease can cause **microcytic or normocytic anemia** and elevated ferritin (as ferritin is an acute phase reactant), the degree of **microcytosis** (MCV 60 fL) is more profound than typically seen in ACD. - ACD usually involves **inflammation or infection**, but the lab values provided more strongly point away from pure ACD. *Iron deficiency anemia* - **Iron deficiency anemia** is characterized by **microcytic hypochromic anemia** but would present with **low serum ferritin** levels, indicating depleted iron stores. - The patient's **elevated ferritin** (185 µg/L) rules out iron deficiency as the primary cause. *Lead poisoning* - **Lead poisoning** can cause **microcytic anemia** by interfering with heme synthesis, but it is typically associated with a **basophilic stippling** on peripheral blood smear and elevated blood lead levels. - It does not typically present with **elevated ferritin** as a classic feature, and the overall clinical picture is more consistent with a genetic hemoglobinopathy.

Q: A patient who is on treatment for hyperlipidemia develops gallstones. What is the mechanism of action of the causative drug that was given to this patient?

Activates PPAR alpha. ***Activates PPAR alpha*** * Activation of **PPAR alpha (Peroxisome Proliferator-Activated Receptor alpha)** by fibrates can lead to increased cholesterol secretion into bile [1]. * This increased biliary cholesterol saturation predisposes patients to **cholesterol gallstone** formation. *Decreases VLDL* * While fibrates do decrease **VLDL (Very Low-Density Lipoprotein)** production, this specific action is not the primary mechanism by which they cause gallstones [1]. * The reduction in VLDL is beneficial for triglyceride lowering, but the gallstone risk relates to cholesterol metabolism. *Binds to deoxycholic acid* * This mechanism is characteristic of **bile acid sequestrants** like cholestyramine, which bind to bile acids in the gut to prevent their reabsorption. * Bile acid sequestrants are not typically associated with an increased risk of gallstones; in fact, they can sometimes be used to reduce gallstones in specific contexts. *Inhibits HMG CoA reductase* * This is the mechanism of action for **statins**, which are highly effective in lowering LDL cholesterol by inhibiting the rate-limiting enzyme in cholesterol synthesis [2]. * Statins are not generally associated with an increased risk of gallstones; some studies even suggest a potential protective effect [3].

Q: Choose the correct options regarding the route of administration and bioavailability. A- Intravenous =1 B- 0.75< Oral <1 C-0.75 <IM ≤ 1 D- 0.75<SC ≤ 1 IM - Intramuscular SC- Subcutaneous

A, C, D. ***A, C, D*** - Intravenous (IV) administration has **100% bioavailability** because the drug enters the systemic circulation directly, bypassing any absorption barriers. - Intramuscular (IM) and subcutaneous (SC) routes generally have **high bioavailability**, often between 75% and 100%, as drugs are absorbed directly into the bloodstream without first-pass metabolism. *A and D* - While options A and D are correct, this choice is incomplete as option C is also a correct statement regarding bioavailability. - IM administration typically results in high systemic bioavailability, similar to SC, making its exclusion here incorrect. *A and C* - While options A and C are correct, this choice is incomplete as option D is also a correct statement regarding bioavailability. - Subcutaneous administration also generally results in high bioavailability, as absorption tends to be complete. *A, B, D* - While options A and D are correct, option B is typically incorrect for oral bioavailability. - Oral bioavailability of many drugs is often less than 0.75 (75%) due to factors like **first-pass metabolism** and incomplete absorption in the gastrointestinal tract.

Q: Which of the following is the most effective oral drug for smoking cessation?

Varenicline. ***Varenicline*** - **Varenicline** is a partial agonist at **α4β2 nicotinic acetylcholine receptors**, reducing the reward from smoking and alleviating withdrawal symptoms. - Clinical trials consistently demonstrate its superior efficacy compared to **bupropion** and **nicotine replacement therapy** in achieving long-term abstinence. - It is the **most effective FDA-approved oral medication** for smoking cessation with quit rates approximately 2-3 times higher than placebo. *Bupropion* - **Bupropion** is an antidepressant that acts as a **norepinephrine-dopamine reuptake inhibitor**, which can reduce cravings and withdrawal symptoms. - While effective, its efficacy is generally considered to be lower than that of **varenicline** for smoking cessation. - It is considered a **first-line alternative** for patients who cannot tolerate varenicline. *Nicotine gum* - **Nicotine gum** is an oral form of nicotine replacement therapy that delivers nicotine without the harmful chemicals of tobacco, helping to manage withdrawal symptoms. - It is effective but less successful than **varenicline** when used as monotherapy, though combination NRT approaches can improve outcomes. - Available in 2 mg and 4 mg strengths, with dosing based on smoking history. *Nortriptyline* - **Nortriptyline** is a tricyclic antidepressant that has shown some efficacy in reducing nicotine withdrawal symptoms, but its use is limited by its side effect profile. - It is considered a **second-line agent** for smoking cessation due to its lower efficacy and greater potential for adverse effects (anticholinergic, cardiac) compared to first-line options like **varenicline** and **bupropion**.

Q: What does zero pressure indicate in the pressure-volume curve?

Functional residual capacity. ***Functional residual capacity*** - This is the lung volume at which the **elastic recoil of the lungs** exactly balances the **elastic recoil of the chest wall**, resulting in zero net pressure across the respiratory system. - At **functional residual capacity (FRC)**, there is no airflow, and the **alveolar pressure equals atmospheric pressure (zero)**, indicating the equilibrium point. - Note: The **transpulmonary pressure remains positive** at FRC (approximately +5 cm H₂O), which keeps the lungs inflated against their elastic recoil. *Inspiratory reserve volume* - This is the **extra volume of air** that can be forcibly inhaled after a normal inspiration. - It involves active inspiration and therefore is associated with a **negative intrathoracic pressure**, not zero pressure. *Tidal volume* - This is the **volume of air inhaled and exhaled** during a normal quiet breathing cycle. - While breathing, pressures fluctuate, and the respiratory system is not at an equilibrium point of **zero pressure** throughout the tidal breath. *Residual volume* - This is the **volume of air remaining in the lungs** after a maximal exhalation. - The chest wall's outward recoil is greater than the lung's inward recoil at this point, resulting in a **negative intrapleural pressure** to keep the lungs from collapsing.

Q: The graph below shows oxygen dissociation curves. What does the curve marked as 'A' indicate?

Myoglobin. ***Myoglobin*** - Curve A shows a **hyperbolic oxygen dissociation curve** which is characteristic of myoglobin, indicating high oxygen affinity even at low partial pressures. - Myoglobin has only one heme group, allowing it to bind a single oxygen molecule with high affinity to **store oxygen in muscles**. *Methemoglobin* - Methemoglobin has a **ferric (Fe3+) iron** in its heme group, which cannot bind oxygen, thus reducing the overall oxygen-carrying capacity. - It would typically cause a **left shift** of the remaining functional hemoglobin's dissociation curve due to increased oxygen affinity, but this isn't directly represented as curve A's primary characteristic. *Carboxyhemoglobinemia* - **Carbon monoxide (CO)** binds to hemoglobin with a much higher affinity than oxygen, forming carboxyhemoglobin. - This binding leads to a **left shift** in the oxygen dissociation curve of the remaining functional hemoglobin and a decreased oxygen-carrying capacity, but curve A represents a species with inherently higher oxygen affinity. *Fetal hemoglobin* - Fetal hemoglobin (HbF) has a **higher affinity for oxygen** than adult hemoglobin (HbA), which is represented by a **left-shifted sigmoidal curve** compared to adult hemoglobin. - While it has higher affinity, its curve is still **sigmoidal**, unlike the hyperbolic curve of myoglobin (A).

Question 1

What is the volume of the prostate in normal adult males?

Accepted Answer

20cc

Answer

50cc

Answer

75cc

Answer

100cc

Question 2

Cyclooxygenase plays a role in which pathway?

Accepted Answer

Prostaglandin

Answer

Leukotriene

Answer

Vitamin K

Answer

Krebs cycle

Question 3

Which of the following statements are true about familial adenomatous polyposis?

1. It is autosomal recessive
2. If not treated, 100% of the cases progress to adenocarcinoma colon.
3. It is associated with a gene mutation in KRAS
4. It is associated with congenital hypertrophy of the retinal pigment epithelium.

Accepted Answer

2 and 4

Answer

None of the options

Answer

1 and 4

Answer

2 and 3

Question 4

The following is a histopathological image of thyroid pathology. What is the diagnosis?

Accepted Answer

Medullary carcinoma of thyroid

Answer

Papillary carcinoma of thyroid

Answer

Follicular carcinoma of thyroid

Answer

Anaplastic carcinoma of thyroid

Question 5

A 10-year-old boy presented with fatigue. Investigations revealed: Hemoglobin, 9 g/dL; MCV, 60 fL; MCH, 20 pg; and serum ferritin, 185 µg/L. The TLC was elevated and showed predominant lymphocytes and neutrophils. What is the likely diagnosis in this patient?

**Normal values:**
- Serum ferritin: 50-150 µg/L

Accepted Answer

Beta thalassemia trait

Answer

Anemia of chronic disease

Answer

Iron deficiency anemia

Answer

Lead poisoning

Question 6

A patient who is on treatment for hyperlipidemia develops gallstones. What is the mechanism of action of the causative drug that was given to this patient?

Accepted Answer

Activates PPAR alpha

Answer

Binds to deoxycholic acid

Answer

Decreases VLDL

Answer

Inhibits HMG CoA reductase

Question 7

Choose the correct options regarding the route of administration and bioavailability.
A- Intravenous =1
B- 0.75< Oral <1
C-0.75 <IM ≤ 1
D- 0.75<SC ≤ 1
IM - Intramuscular
SC- Subcutaneous

Accepted Answer

A, C, D

Answer

A and D

Answer

A and C

Answer

A, B, D

Question 8

Which of the following is the most effective oral drug for smoking cessation?

Accepted Answer

Varenicline

Answer

Bupropion

Answer

Nortriptyline

Answer

Nicotine gum

Question 9

What does zero pressure indicate in the pressure-volume curve?

Accepted Answer

Functional residual capacity

Answer

Inspiratory reserve volume

Answer

Tidal volume

Answer

Residual volume

Question 10

The graph below shows oxygen dissociation curves. What does the curve marked as 'A' indicate?

Accepted Answer

Myoglobin

Answer

Methemoglobin

Answer

Carboxyhemoglobinemia

Answer

Fetal hemoglobin

INI-CET 2022

Anatomy

Biochemistry

Internal Medicine

Pathology

Pediatrics

Pharmacology

Physiology