INI-CET 2024 Practice Questions

Q: Which type of mutation can act as a suppressor to restore the wild-type phenotype in organisms carrying a mutant gene?

Mutation of tRNA. ***Mutation of tRNA*** - A **tRNA suppressor mutation** can alter its anticodon, allowing it to recognize a **stop codon** (nonsense suppressor) or a missense codon, and insert an amino acid, thereby suppressing the original mutation. - This is a classic example of an **intergenic suppressor mutation** that acts at a different genetic locus from the original mutation. - These suppressors are particularly effective for **nonsense mutations** (premature stop codons) and certain missense mutations by correcting the decoding error during translation. *Frameshift mutation of coding gene* - A single frameshift mutation causes a shift in the **reading frame**, leading to a completely different protein sequence downstream and often a premature stop codon, which would worsen the phenotype. - While a **second compensating frameshift** mutation in the same gene could theoretically restore the reading frame (acting as an intragenic suppressor), this is context-dependent and less reliable than tRNA suppressors. - The question asks for mutations that "can act as a suppressor," and **tRNA mutations are the more universally recognized and reliable suppressor mechanism** in classical genetics. *Deletion of mutant gene* - **Deleting the mutant gene** removes the genetic information entirely but does not restore wild-type function; instead, it typically results in **loss of function** or complete absence of the protein. - This would lead to a **null phenotype** rather than restoration of wild-type phenotype, especially if the gene is essential. *Addition of another normal gene* - The **addition of another normal (wild-type) gene copy** provides a functional protein that can compensate for the mutant gene's deficiency. - While this can restore a wild-type phenotype, it represents **gene complementation** or gene therapy, not a true suppressor mutation that modifies the interpretation or expression of the existing mutant allele.

Q: Which of the following disorders presents with repeated catalase positive infections?

CGD. ***CGD*** - Chronic Granulomatous Disease (CGD) is characterized by a defect in **NADPH oxidase**, preventing phagocytes from producing a **respiratory burst** to kill certain bacteria and fungi. - Patients with CGD are particularly susceptible to infections by **catalase-positive organisms** because these organisms degrade hydrogen peroxide, which CGD phagocytes rely on for killing. *Chediak higashi syndrome* - This syndrome involves defective lysosomal trafficking, leading to impaired neutrophil chemotaxis and degranulation, resulting in recurrent infections, but not specifically to **catalase-positive organisms**. - Other features include **partial albinism**, peripheral neuropathy, and normal respiratory burst. *SCID* - Severe Combined Immunodeficiency (SCID) involves a profound defect in both **T-cell and B-cell immunity**, leading to severe and recurrent infections by a wide range of pathogens, not limited to catalase-positive ones [1]. - Patients typically present in infancy with **failure to thrive**, opportunistic infections, and lack of lymphoid tissue [1]. *X linked hypogammaglobulinemia* - Also known as **Bruton's agammaglobulinemia**, this disorder involves a defect in B-cell maturation, leading to the absence of antibodies and recurrent bacterial infections [1]. - The infections are typically with **encapsulated bacteria** and are not specifically linked to catalase-positive organisms [1].

Q: Least common cause for bilateral pedal edema

Chronic vascular insufficiency. ***Chronic vascular insufficiency*** - While chronic venous insufficiency is a common cause of bilateral pedal edema, **arterial insufficiency** (a type of chronic vascular insufficiency) is a much less common cause of pure edema and is more often associated with **ischemic pain**, **ulcers**, and **skin atrophy** [1]. - **Arterial insufficiency** primarily causes limb ischemia rather than significant edema, differentiating it from situations where fluid retention is the primary issue [2]. *CKD* - **Chronic kidney disease (CKD)** leads to impaired fluid and sodium excretion, causing generalized fluid overload. - This fluid overload commonly manifests as **bilateral pedal edema** due to gravity-dependent fluid accumulation. *CLD* - **Chronic liver disease (CLD)**, particularly cirrhosis, results in **portal hypertension** and decreased hepatic synthesis of **albumin**. - This leads to reduced oncotic pressure and increased hydrostatic pressure, driving fluid into the extravascular space, often causing **ascites** and **bilateral pedal edema**. *HF with reduced ejection fraction* - **Heart failure with reduced ejection fraction (HFrEF)** impairs the heart's ability to pump blood effectively, leading to fluid backup in the venous system [2]. - This increased hydrostatic pressure in the peripheral capillaries directly causes **bilateral pedal edema** as fluid extravasates into the interstitial space [2].

Q: A 32-year-old female at 36 weeks of pregnancy presents with BP 170/100 mmHg, visual disturbances, headache, urine protein 3+. What will be the next step?

IV labetalol, magnesium sulfate (MgSO4), expedite delivery. ***IV labetalol, magnesium sulfate (MgSO4), expedite delivery*** - The patient presents with **severe preeclampsia** (BP > 160/110 mmHg, visual disturbances, headache, proteinuria) at 36 weeks, requiring **antihypertensive therapy** (labetalol) and seizure prophylaxis (**magnesium sulfate**). - Given the severe features and gestational age, **expedited delivery** is indicated to prevent maternal and fetal complications, as expectant management beyond severe preeclampsia at this stage offers minimal benefit and increased risk. *IV labetalol and delivery at 37 weeks* - While IV labetalol is appropriate for **blood pressure control**, delaying delivery to 37 weeks might not be optimal given the **severe features of preeclampsia** at 36 weeks, increasing risks for both mother and fetus. - The plan is incomplete without mentioning **seizure prophylaxis** with magnesium sulfate, which is crucial for severe preeclampsia. *IV labetalol, dexamethasone, and immediate termination of pregnancy* - **Dexamethasone** is used for **fetal lung maturity** in preterm deliveries and is not indicated for immediate termination unless the fetus is preterm and lung maturity is a concern. At 36 weeks, lung maturity is usually established. - While immediate termination might be considered, the phrase "immediate termination" implies C-section without considering vaginal delivery and overlooks the need for **seizure prophylaxis**. *IV labetalol, dexamethasone, and conservative management* - **Dexamethasone** is not a primary treatment for severe preeclampsia itself but rather for **fetal lung maturation** in preterm deliveries, which is less critical at 36 weeks. - **Conservative management** is generally inappropriate for **severe preeclampsia** at 36 weeks, as it increases maternal and fetal risk; delivery is the definitive treatment.

Q: In which of the following conditions are cannabinoids not commonly used for treatment?

Rett syndrome. ***Rett syndrome*** - Cannabinoids are **NOT commonly used** as an established treatment for **Rett syndrome** - While some research is exploring their potential therapeutic role, they remain **investigational only** and lack FDA approval for this indication - Current management focuses on symptomatic treatment including physical therapy, anti-epileptics for seizures, and supportive care - Unlike the other conditions listed, there is **no established cannabinoid therapy** for Rett syndrome in clinical practice *Dravet syndrome* - **Cannabidiol (CBD/Epidiolex)** is **FDA-approved** and commonly used for treatment of seizures associated with **Dravet syndrome** - Demonstrates significant efficacy in reducing seizure frequency in this severe infantile-onset epilepsy - Represents a major therapeutic advance for this treatment-resistant condition *Tuberous sclerosis* - **Cannabidiol (CBD/Epidiolex)** received **FDA approval in 2018** for treatment of seizures associated with **tuberous sclerosis complex (TSC)** - Commonly used as an adjunctive therapy alongside other treatments like vigabatrin or mTOR inhibitors (everolimus) - Clinical trials demonstrated significant reduction in seizure frequency in TSC patients *Lennox-Gastaut Syndrome* - **Cannabidiol (CBD/Epidiolex)** is **FDA-approved** for seizures associated with **Lennox-Gastaut Syndrome (LGS)** - Commonly used in this severe epileptic encephalopathy characterized by multiple seizure types and developmental delay - Effective in reducing seizure burden in patients refractory to traditional anti-epileptic drugs

Q: Drug of choice for Enterococcus infection in a patient allergic to penicillin?

Vancomycin. ***Vancomycin*** - **Vancomycin** is a glycopeptide antibiotic that is effective against **Gram-positive bacteria**, including *Enterococcus*, especially in patients with a **penicillin allergy**. - It inhibits **cell wall synthesis** by binding to the D-Ala-D-Ala terminus of peptidoglycan precursors, a different mechanism from penicillins. *Streptomycin* - **Streptomycin** is an aminoglycoside that inhibits **protein synthesis** and is primarily used in **combination therapy** for serious *Enterococcal* infections, but typically alongside a cell-wall active agent (like penicillin or vancomycin) for synergistic killing in endocarditis or other severe infections. - It is not usually recommended as a **monotherapy** for *Enterococcus*, especially in the context of penicillin allergy, as it doesn't provide bactericidal activity on its own against all enterococcal strains. *Cephalosporin* - **Cephalosporins** are **not active** against *Enterococcus spp.* as these bacteria intrinsically lack the **penicillin-binding proteins (PBPs)** that cephalosporins target effectively. - This **intrinsic resistance** makes cephalosporins an inappropriate choice for treating *Enterococcal* infections, regardless of penicillin allergy status. *Rifampicin* - **Rifampicin** is an antibiotic primarily used for **Mycobacterial infections** (e.g., tuberculosis) and some **Staphylococcal infections**, often in combination to prevent resistance. - It has **poor activity** against *Enterococcus* and is not a recommended treatment for *Enterococcal* infections.

Q: mhGAP program includes all of the following disorders except?

Personality Disorders. ***Personality Disorders*** - The **mhGAP program** (Mental Health Gap Action Programme) focuses on scaling up services for common, severe mental, neurological, and substance use disorders in low- and middle-income countries. - **Personality disorders** are generally not included in the core conditions addressed by the mhGAP program due to their complex and chronic nature, requiring specialized and long-term management that may be beyond the scope of primary care settings targeted by mhGAP. *Schizophrenia* - **Schizophrenia** is one of the priority conditions addressed by the mhGAP program, recognizing its severity and significant impact on individuals and communities. - The program provides guidelines for the recognition, management, and long-term care of schizophrenia at the primary healthcare level. *Depression* - **Depression** is a core focus of the mhGAP program, given its high prevalence and treatability in primary care settings. - mhGAP provides clear guidelines for the identification, basic management, and follow-up of individuals with depression. *Childhood mental disorder* - **Childhood mental disorders**, such as conduct disorder, attention-deficit/hyperactivity disorder (ADHD), and developmental disabilities, are also included as priority conditions within the mhGAP program. - The program aims to improve the detection and basic management of these conditions in children and adolescents, promoting early intervention.

Q: Which of the following is not associated with Korsakoff psychosis?

Ophthalmoplegia. ***Ophthalmoplegia*** - **Ophthalmoplegia** is a key feature of **Wernicke encephalopathy**, the acute phase preceding Korsakoff psychosis, but is not directly a symptom of Korsakoff psychosis itself. - While both conditions are linked to thiamine deficiency, **Korsakoff psychosis** primarily manifests as chronic memory deficits. *Amnesia* - **Anterograde amnesia** (inability to form new memories) and **retrograde amnesia** (loss of past memories) are defining characteristics of Korsakoff psychosis. - This severe memory impairment is a result of damage to areas like the **mammillary bodies** and **thalamus**. *Confabulation* - **Confabulation**, the fabrication of distorted or misinterpreted memories without an intention to deceive, is a common symptom in patients with Korsakoff psychosis. - This occurs as patients attempt to fill in gaps in their memory loss, often believing their own stories. *Polyneuropathy* - **Polyneuropathy**, nerve damage affecting multiple peripheral nerves, causing symptoms like pain, numbness, and muscle weakness, is associated with chronic **alcoholism** and **thiamine deficiency**. - While not a direct psychological symptom, it is frequently seen in the same patient population that develops Korsakoff psychosis due to shared etiology.

Question 1

Which type of mutation can act as a suppressor to restore the wild-type phenotype in organisms carrying a mutant gene?

Accepted Answer

Mutation of tRNA

Answer

Frameshift mutation of coding gene

Answer

Deletion of mutant gene

Answer

Addition of another normal gene

Question 2

Which of the following disorders presents with repeated catalase positive infections?

Accepted Answer

CGD

Answer

Chediak higashi syndrome

Answer

SCID

Answer

X linked hypogammaglobulinemia

Question 3

Least common cause for bilateral pedal edema

Accepted Answer

Chronic vascular insufficiency

Answer

CKD

Answer

CLD

Answer

HF with reduced ejection fraction

Question 4

A 32-year-old female at 36 weeks of pregnancy presents with BP 170/100 mmHg, visual disturbances, headache, urine protein 3+. What will be the next step?

Accepted Answer

IV labetalol, magnesium sulfate (MgSO4), expedite delivery

Answer

IV labetalol and delivery at 37 weeks

Answer

IV labetalol, dexamethasone, and immediate termination of pregnancy

Answer

IV labetalol, dexamethasone, and conservative management

Question 5

A patient presents with neck swelling causing compression of the trachea and esophagus. Histopathological assessment reveals cell nests and pink extracellular amyloid stroma. What is the cell of origin of the tumor associated with these findings?

Accepted Answer

Parafollicular C cells

Answer

Hurthle cells

Answer

Follicular cells

Answer

Chief cells

Question 6

Molecular genetic testing is used to detect all of the following except?

Accepted Answer

Translocation

Answer

Deletion

Answer

Amplification

Answer

Point mutation

Question 7

In which of the following conditions are cannabinoids not commonly used for treatment?

Accepted Answer

Rett syndrome

Answer

Tuberous sclerosis

Answer

Lennox-Gastaut Syndrome

Answer

Dravet syndrome

Question 8

Drug of choice for Enterococcus infection in a patient allergic to penicillin?

Accepted Answer

Vancomycin

Answer

Streptomycin

Answer

Cephalosporin

Answer

Rifampicin

Question 9

mhGAP program includes all of the following disorders except?

Accepted Answer

Personality Disorders

Answer

Schizophrenia

Answer

Depression

Answer

Childhood mental disorder

Question 10

Which of the following is not associated with Korsakoff psychosis?

Accepted Answer

Ophthalmoplegia

Answer

Amnesia

Answer

Confabulation

Answer

Polyneuropathy

INI-CET 2024

Biochemistry

Internal Medicine

Obstetrics and Gynecology

Pathology

Pharmacology

Psychiatry