INI-CET 2022 Practice Questions

Q: The signal sequence in a type 2 membrane protein with N-terminal facing cytoplasm is located in?

Middle of protein. ***Middle of protein*** - For a type 2 membrane protein with the **N-terminal facing the cytoplasm**, the **start-transfer sequence** (which acts as a signal sequence) is found in the **middle of the protein**. - This **internal signal sequence** allows for membrane integration with the correct orientation, often functioning as a **transmembrane domain**. *C-terminal* - A C-terminal signal is typically seen in **Type I membrane proteins** where the **N-terminus is in the ER lumen** and the C-terminus is in the cytoplasm. - This orientation requires a **stop-transfer sequence** in the middle of the protein. *Both N and C terminal* - While some proteins may have multiple signal sequences, a single protein typically utilizes **one dominant signal** for its initial targeting and membrane insertion. - Having both an N-terminal and C-terminal primary signal for integration would lead to **conflicting targeting signals** for this specific type of protein. *N-terminal* - An N-terminal signal sequence is characteristic of **Type I membrane proteins** or **secreted proteins**, guiding them to the ER and often being cleaved. - In a **type 2 protein**, with the **N-terminus in the cytoplasm**, an N-terminal signal would result in the N-terminus entering the ER lumen, contradicting the given orientation.

Q: What is the most common site of abdominal tuberculosis?

Ileocecal junction. ***Ileocecal junction*** - The **ileocecal junction** is the most common site for abdominal tuberculosis due to its rich lymphoid tissue (Peyer's patches) and physiological stasis. - Tuberculous infection at this site can lead to **mucosal ulceration**, stricture formation, and mass lesions. *Colon* - While the colon can be affected by abdominal tuberculosis, it is **less common** than the ileocecal region. - Colonic involvement often presents with symptoms such as abdominal pain, diarrhea, and weight loss. *Small intestine* - Though other parts of the small intestine can be involved, the **distal ileum** and its junction with the cecum are disproportionately affected. - Involvement of the jejunum and duodenum is less frequent. *Rectum* - **Rectal involvement** in abdominal tuberculosis is rare and typically occurs in conjunction with more extensive colonic or disseminated disease. - Symptoms may include tenesmus, rectal bleeding, or fistula formation.

Q: A woman presents with altered sensorium, breathlessness, hypotension and bradycardia. Examination revealed non-pitting edema of the extremities. She has a long -standing history of weight gain, constipation, cold intolerance, and menorrhagia. What is the most likely diagnosis?

Myxedema coma. ***Myxedema coma*** - The constellation of **altered sensorium**, **hypotension**, **bradycardia**, and **non-pitting edema** in a patient with a history of **weight gain**, **constipation**, **cold intolerance**, and **menorrhagia** (symptoms of hypothyroidism) is highly suggestive of myxedema coma [2]. - This is an **extreme manifestation of severe, untreated hypothyroidism**, characterized by decompensation of multiple organ systems. *Hyperthyroidism* - Hyperthyroidism usually presents with symptoms like **tachycardia**, **tremors**, **weight loss**, and **heat intolerance** [1], [3], which are contrary to the patient's presentation. - It would not explain the **bradycardia**, **non-pitting edema**, or chronic symptoms like **constipation** and **cold intolerance**. *Cardiogenic shock* - While cardiogenic shock can cause **hypotension** and **altered sensorium**, it is typically characterized by signs of **cardiac dysfunction** such as elevated JVP, crackles, and often **tachycardia** (reflexive or primary), not bradycardia [4]. - It does not account for the **long-standing hypothyroid symptoms** like weight gain, constipation, and cold intolerance. *Septic shock* - Septic shock is primarily due to a severe infection, leading to **fever** (though hypothermia can occur in severe cases), **leukocytosis**, and signs of systemic inflammatory response (SIRS), which are not mentioned. - The patient's chronic symptoms are inconsistent with an acute infectious process as the primary cause of shock.

Q: A patient presented with ipsilateral Horner's syndrome, ipsilateral loss of pain and temperature sensations in the face, vertigo with numbness and loss of sweating and dysarthria on the contralateral side. All these symptoms are caused due to a lesion in:

B and D. ***B and D*** - This complex of symptoms, including ipsilateral **Horner's syndrome**, ipsilateral facial **pain and temperature loss**, **vertigo**, and contralateral **pain and temperature loss** on the body, is characteristic of **Wallenberg syndrome**, also known as **lateral medullary syndrome**. - Wallenberg syndrome is caused by an infarction in the **vertebral artery** (dorsal portion) or its branch, the **posterior inferior cerebellar artery (PICA)**, which supplies the lateral medulla. *A and B* - This option refers to lesions in the **medial medulla**, which would present with completely different symptoms such as contralateral **hemiplegia**, contralateral **loss of proprioception**, and ipsilateral **tongue deviation**. - While both medulla, the distinct clinical presentations differentiate **medial from lateral medullary lesions**. *B, C, D* - This combination attempts to incorporate a lesion in the **medial medulla** (C) with the other relevant areas. - However, the symptom complex clearly points to **lateral medullary involvement**, and including the medial medulla would suggest a different or more extensive stroke. *A, B, C* - This option includes the **anterior spinal artery**, which primarily supplies the **medial medulla** and spinal cord, leading to distinct symptoms. - Involvement of the **anterior spinal artery** would result in motor deficits and loss of pain/temperature on the contralateral side, but would not typically cause **Horner's syndrome** or the intense **vertigo** seen in lateral medullary syndrome.

Q: The Hb is 5 g/dL and the reticulocyte count is 9%. What is the corrected reticulocyte count?

3. ***3*** - The **corrected reticulocyte count (CRC)** is calculated to adjust for varying degrees of anemia, providing a more accurate assessment of bone marrow erythropoietic activity. The formula is: **CRC = observed reticulocyte % × (patient's HCT / normal HCT)**. - Assuming a normal hematocrit (HCT) of 45% and a direct hemoglobin to hematocrit conversion of 1:3 for 5 g/dL Hb (so HCT = 15%), then CRC = 9% × (15/45) = 9% × 1/3 = **3%**. *5* - This value is likely obtained by an **incorrect calculation** or by applying an inappropriate correction factor. - It does not properly account for the **severity of anemia** in the calculation of the corrected reticulocyte count [2]. *1.8* - This result may represent confusion with the **Reticulocyte Production Index (RPI)**, which further corrects for premature reticulocyte release by dividing CRC by a maturation time factor (typically 1.5-2 in severe anemia) [1]. - However, the question specifically asks for the **corrected reticulocyte count**, not the RPI, making this an inappropriate over-correction. *4.5* - This value might be a result of **dividing the observed reticulocyte count by a factor of 2**, which is not the standard correction for anemia. - It does not accurately reflect the **bone marrow's response** to the severe anemic state. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 586-587. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591.

Q: A lady who had undergone mastectomy for breast cancer is being treated with tamoxifen. How long should it be stopped before she can conceive?

3 months. ***3 months*** - Tamoxifen has a long half-life, and it can remain in the body for up to several weeks after the last dose. A washout period of **at least 3 months** is recommended to minimize exposure of a developing fetus to the drug. - Exposure to tamoxifen during pregnancy is associated with potential risks such as **birth defects** and impaired fetal development due to its anti-estrogenic effects disrupting hormonal balance. *No need to stop* - This is incorrect because tamoxifen is **teratogenic**, meaning it can cause birth defects if taken during pregnancy. - Continuing tamoxifen during pregnancy would expose the fetus to serious risks, necessitating a planned discontinuation before conception. *Can be stopped and conceived soon after stopping* - This is incorrect because tamoxifen has a relatively **long half-life**, meaning it takes time for the drug to be completely eliminated from the body. - A washout period is necessary to ensure the drug levels are low enough to prevent fetal exposure and potential harm. *1 month* - A 1-month washout period is generally considered **insufficient** given tamoxifen's pharmacokinetic profile. - This shorter period does not adequately account for the drug's long half-life, increasing the risk of fetal exposure and potential complications.

Q: A man was brought to the emergency room after poisoning with an unknown substance. Muscarinic poisoning was suspected and he was treated for the same. What is the possible presenting feature which led to the diagnosis?

Bradycardia. ***Bradycardia*** - Muscarinic poisoning stimulates **parasympathetic nervous system** activity, leading to a decrease in heart rate. - This **bradycardia** is a classic sign of excessive muscarinic receptor activation, as seen with organophosphate or carbamate poisoning [1, 2].*Diuresis* - While muscarinic receptor activation can increase bladder detrusor contraction (leading to urinary urgency and frequency) [1, 2], **diuresis** (increased urine production) is not a primary or direct presenting feature of muscarinic poisoning. - Instead, the focus is on incontinence rather than simply increased urine output.*Mydriasis* - **Mydriasis** (pupil dilation) is associated with **anticholinergic poisoning**, which blocks muscarinic receptors. - Muscarinic poisoning, conversely, causes **miosis** (pupil constriction) due to excessive stimulation of muscarinic receptors in the iris sphincter muscle.*Muscle fasciculations* - **Muscle fasciculations** are a characteristic sign of **nicotinic receptor overstimulation**, not muscarinic [1, 3]. - While both nicotinic and muscarinic receptors are activated in organophosphate poisoning, fasciculations point to the **nicotinic effects** at the neuromuscular junction [1, 3].

Q: Which among the following organs has the least arteriovenous oxygen difference?

Kidney. ***Kidney*** - The **kidney** has the lowest arteriovenous oxygen difference among these organs because its metabolic activity, relative to its blood supply, is designed for filtration rather than high oxygen extraction for work. - A significant portion of the kidney's oxygen consumption is related to **active transport** and **reabsorption**, but its unusually high blood flow (about 20-25% of cardiac output) ensures that the oxygen content of venous blood remains high. *Liver* - The liver receives a **dual blood supply** (hepatic artery and portal vein) and is highly metabolically active due to its roles in synthesis, detoxification, and nutrient processing, leading to a substantial oxygen extraction and thus a larger arteriovenous oxygen difference. - It has a significant oxygen demand for its numerous physiological functions, resulting in a lower oxygen content in its venous outflow compared to arterial blood. *Skin* - Skin blood flow is highly variable and plays a crucial role in **thermoregulation** in addition to metabolic needs. - While its baseline metabolic rate is moderate, its oxygen extraction can vary, but generally, it has a larger arteriovenous oxygen difference due to the oxygen demand of its various cellular layers and structures. *Brain* - The **brain** has a consistently high metabolic rate and continuous oxygen demand, consuming about 20% of the body's total oxygen at rest. - This consistent and high demand for oxygen results in a relatively large arteriovenous oxygen difference as it extracts a significant portion of oxygen from the arterial blood.

Q: A 14-year-old girl presented with sudden-onset blindness for the past 4 hours. However, on history taking, it is noted that she is not concerned about it. However, she is concerned that her mother passed away recently and that she should have spent more time with her. Physical examination findings are normal. Which of the following is true about the condition?

In children, it occurs more in females than in males. **In children, it occurs more in females than in males** - **Conversion disorders** (functional neurological symptom disorder) are more prevalent in **females** across childhood, adolescence, and adulthood. - The patient's **sudden-onset blindness** without medical cause, coupled with a lack of concern (**la belle indifférence**) and a psychological stressor (mother's death), points to a conversion disorder, which aligns with higher female prevalence in this age group. *In adults, equally among males and females* - This statement is incorrect as conversion disorders, including sudden-onset blindness, are generally more common in **adult females** than males. - The prevalence in adults is not equal; there is a clear gender disparity, with women being more affected. *In children, equally among males and females* - While it can occur in both sexes, the prevalence of conversion disorder in children is not equal; it is observed more frequently in **females**. - Studies consistently report a female-to-male ratio greater than 1 in pediatric populations. *In adults, it occurs more in males than in females* - This statement is incorrect; in adults, conversion disorders are significantly more common in **females**. - The classic presentation, as seen in this case, fits the typical profile observed in female patients experiencing significant psychological distress.

Q: A 29 year old lady came to psychiatry OPD with symptoms of hypomania. She has a past history of manic episode. Now, she is planning to conceive. Which drug should be avoided for being highly teratogenic to the fetus?

Valproate. ***Valproate*** - **Valproate** is highly **teratogenic** and is associated with multiple birth defects, including **neural tube defects** (e.g., spina bifida), cardiac anomalies, and craniofacial defects. - Due to its significant risks, it is generally **contraindicated** in women of childbearing potential, especially during pregnancy, unless no other suitable alternatives exist. *Oxcarbazepine* - While it has some teratogenic risk (e.g., cleft palate), the risk is generally considered **lower than valproate**. - It is often favored over valproate in pregnant women requiring mood stabilizers, but still requires careful risk-benefit assessment. *Lithium* - **Lithium** is associated with an increased risk of **Ebstein's anomaly**, a specific cardiac defect, if used during the first trimester. - However, the overall risk of major malformations is still **lower than valproate**, and it can be used with careful monitoring if other options are not viable. *Olanzapine* - **Olanzapine** is an **atypical antipsychotic** that can be used as a mood stabilizer and is considered to have a **relatively lower teratogenic risk** compared to anticonvulsants like valproate. - While it's not entirely risk-free (associated with gestational diabetes and fetal growth issues), it's often a safer option in pregnancy for bipolar disorder than valproate.

Question 1

The signal sequence in a type 2 membrane protein with N-terminal facing cytoplasm is located in?

Accepted Answer

Middle of protein

Answer

C-terminal

Answer

Both N and C terminal

Answer

N-terminal

Question 2

What is the most common site of abdominal tuberculosis?

Accepted Answer

Ileocecal junction

Answer

Colon

Answer

Small intestine

Answer

Rectum

Question 3

A woman presents with altered sensorium, breathlessness, hypotension and bradycardia.
Examination revealed non-pitting edema of the extremities. She has a long -standing history of weight gain, constipation, cold intolerance, and menorrhagia. What is the most likely diagnosis?

Accepted Answer

Myxedema coma

Answer

Hyperthyroidism

Answer

Cardiogenic shock

Answer

Septic shock

Question 4

A patient presented with ipsilateral Horner's syndrome, ipsilateral loss of pain and temperature sensations in the face, vertigo with numbness and loss of sweating and dysarthria on the contralateral side. All these symptoms are caused due to a lesion in:

Accepted Answer

B and D

Answer

A and B

Answer

B, C, D

Answer

A, B, C

Question 5

The Hb is 5 g/dL and the reticulocyte count is 9%. What is the corrected reticulocyte count?

Accepted Answer

3

Answer

5

Answer

1.8

Answer

4.5

Question 6

A lady who had undergone mastectomy for breast cancer is being treated with tamoxifen. How long should it be stopped before she can conceive?

Accepted Answer

3 months

Answer

No need to stop

Answer

Can be stopped and conceived soon after stopping

Answer

1 month

Question 7

A man was brought to the emergency room after poisoning with an unknown substance.
Muscarinic poisoning was suspected and he was treated for the same. What is the possible presenting feature which led to the diagnosis?

Accepted Answer

Bradycardia

Answer

Diuresis

Answer

Mydriasis

Answer

Muscle fasciculations

Question 8

Which among the following organs has the least arteriovenous oxygen difference?

Accepted Answer

Kidney

Answer

Liver

Answer

Skin

Answer

Brain

Question 9

A 14-year-old girl presented with sudden-onset blindness for the past 4 hours. However, on history taking, it is noted that she is not concerned about it. However, she is concerned that her mother passed away recently and that she should have spent more time with her. Physical examination findings are normal. Which of the following is true about the condition?

Accepted Answer

In children, it occurs more in females than in males

Answer

In adults, equally among males and females

Answer

In children, equally among males and females

Answer

In adults, it occurs more in males than in females

Question 10

A 29 year old lady came to psychiatry OPD with symptoms of hypomania. She has a past history of manic episode. Now, she is planning to conceive. Which drug should be avoided for being highly teratogenic to the fetus?

Accepted Answer

Valproate

Answer

Oxcarbazepine

Answer

Lithium

Answer

Olanzapine

INI-CET 2022

Biochemistry

Internal Medicine

Pathology

Pharmacology

Physiology

Psychiatry