Biochemistry
1 questionsWhat is the most common cause of pure gonadal dysgenesis with XY karyotype?
INI-CET 2023 - Biochemistry INI-CET Practice Questions and MCQs
Question 21: What is the most common cause of pure gonadal dysgenesis with XY karyotype?
- A. Deletion
- B. Point mutation (Correct Answer)
- C. Insertion
- D. Translocation
Explanation: Point mutation - The most common genetic cause of **pure gonadal dysgenesis with XY karyotype** (Swyer syndrome) is a **point mutation** within the **SRY gene**, located on the Y chromosome [1]. - Point mutations include **missense mutations** (amino acid substitution) and **nonsense mutations** (premature stop codon), both of which can render the SRY protein non-functional. - This specific type of mutation leads to a non-functional SRY protein, preventing the development of testes in an individual with an XY karyotype and resulting in streak gonads [1]. *Deletion* - While deletions involving the SRY gene can cause XY gonadal dysgenesis, **complete deletion** of SRY is less common than point mutations as the primary cause of pure gonadal dysgenesis. - Larger deletions on the Y chromosome might also affect other genes, leading to a broader spectrum of phenotypes. *Insertion* - **Insertions** are a type of frameshift mutation where nucleotides are added to the DNA sequence. - While insertions in the SRY gene could theoretically cause gonadal dysgenesis, they are much less commonly reported than point mutations as the cause of Swyer syndrome. *Translocation* - **Translocations** involving the SRY gene, such as SRY being translocated to an X chromosome, can lead to sex reversal (XX male phenotype). - However, for pure XY gonadal dysgenesis (where SRY is present but non-functional), translocations are not the most common underlying genetic mechanism.
Microbiology
1 questionsA peculiar organism has resistance to azithromycin, but is sensitive to ticarcillin, clavulanic acid, cotrimoxazole. Identify the organism?
INI-CET 2023 - Microbiology INI-CET Practice Questions and MCQs
Question 21: A peculiar organism has resistance to azithromycin, but is sensitive to ticarcillin, clavulanic acid, cotrimoxazole. Identify the organism?
- A. Pseudomonas
- B. Staphylococcus
- C. Stenotrophomonas (Correct Answer)
- D. Mycoplasma
Explanation: ***Stenotrophomonas*** - *Stenotrophomonas maltophilia* is intrinsically **resistant to azithromycin** and other macrolides due to its efflux pumps. - It is known to be sensitive to **ticarcillin-clavulanic acid** (a beta-lactam/beta-lactamase inhibitor combination) and **cotrimoxazole** (trimethoprim-sulfamethoxazole), which are common treatment options. *Pseudomonas* - *Pseudomonas aeruginosa* is generally **resistant to macrolides like azithromycin** but can exhibit varying sensitivity to antibiotics. - However, it often shows resistance to cotrimoxazole and ticarcillin-clavulanic acid is not a first-line agent, and it would typically be sensitive to other antipseudomonal beta-lactams (e.g., piperacillin-tazobactam, carbapenems). *Staphylococcus* - Many *Staphylococcus* species, particularly **MRSA**, are resistant to azithromycin. - However, *Staphylococcus* species are typically sensitive to other antibiotics like **vancomycin**, and are generally not sensitive to ticarcillin-clavulanic acid, and their susceptibility to cotrimoxazole varies depending on the species and resistance mechanisms. *Mycoplasma* - *Mycoplasma* species are **intrinsically resistant to beta-lactam antibiotics like ticarcillin** because they lack a cell wall, which is the target of these drugs. - They are typically sensitive to macrolides like azithromycin and also to cotrimoxazole.
Obstetrics and Gynecology
2 questionsWhich of the following is an established benefit of Hormone Replacement Therapy (HRT)?
A woman presents with painless ulcers on the vulva, she gives a history of having multiple sexual partners and has had a stillbirth at 28 weeks in the past. What is the next best step of investigation?
INI-CET 2023 - Obstetrics and Gynecology INI-CET Practice Questions and MCQs
Question 21: Which of the following is an established benefit of Hormone Replacement Therapy (HRT)?
- A. Decreased risk of endometrial cancer
- B. Decreased risk of breast cancer
- C. Decreased risk of colon cancer
- D. Decreased risk of vertebral fracture (Correct Answer)
Explanation: ***Decreased risk of vertebral fracture*** - HRT is **one of the most well-established benefits** for **prevention of osteoporosis and fractures**, including vertebral fractures. - Estrogen plays a crucial role in maintaining **bone mineral density** by inhibiting osteoclast activity and promoting osteoblast function. - Multiple studies, including the **Women's Health Initiative (WHI)**, have demonstrated a **significant reduction in hip, vertebral, and other osteoporotic fractures** in women taking HRT. - This benefit is recognized by **ACOG, NAMS, and international menopause societies** as a primary indication for HRT in appropriate candidates. *Decreased risk of endometrial cancer* - **Unopposed estrogen therapy** actually **increases the risk of endometrial cancer** due to hyperplasia of the endometrium. - To counteract this, **progestin is added** in women with a uterus receiving HRT, which reduces but does not eliminate the risk increase. - Combined HRT does not provide a net decreased risk below baseline. *Decreased risk of breast cancer* - Combined **estrogen-progestin HRT** has been consistently associated with an **increased risk of breast cancer**, especially with longer durations of use (>5 years). - This was clearly demonstrated in the **WHI trial** and remains a major consideration when prescribing HRT. - Estrogen-only HRT might have a neutral or slightly increased risk, but never a decreased risk. *Decreased risk of colon cancer* - While some observational studies and the **WHI trial** initially showed a reduced incidence of colorectal cancer with HRT, this is **not considered an established or primary indication** for HRT. - Subsequent analyses have shown **inconsistent results**, and any benefit is offset by increased risks. - Current guidelines do **not recommend HRT** for colorectal cancer prevention.
Question 22: A woman presents with painless ulcers on the vulva, she gives a history of having multiple sexual partners and has had a stillbirth at 28 weeks in the past. What is the next best step of investigation?
- A. PCR
- B. VDRL (Correct Answer)
- C. Vaginal swab and culture
- D. NAT
Explanation: ***VDRL*** - The presentation of **painless vulvar ulcers**, a history of **multiple sexual partners**, and a past **stillbirth at 28 weeks** are highly suggestive of **syphilis**. - A **VDRL (Venereal Disease Research Laboratory) test** is a non-treponemal serologic test used for screening and monitoring the treatment of syphilis. *PCR* - While **PCR** can be used to detect the genetic material of *Treponema pallidum*, it is not the primary diagnostic test for syphilis, especially given the classic clinical picture. - It is more commonly used for detecting other sexually transmitted infections (STIs) or for specific situations where direct detection of the organism from a lesion is preferred. *Vaginal swab and culture* - A **vaginal swab and culture** would be appropriate for diagnosing bacterial vaginosis, candidiasis, or certain bacterial STIs, but it is not suitable for diagnosing syphilis. - Syphilis is caused by a spirochete (*Treponema pallidum*) that cannot be cultured on standard media. *NAT* - **Nucleic Acid Amplification Tests (NATs)** are a broad category of tests that include PCR. - Like PCR, while potentially applicable for *Treponema pallidum* detection, they are not the standard or first-line diagnostic investigation for syphilis given the strong clinical indicators.
Ophthalmology
2 questionsIdentify the correct sequence of staining in dry eyes? 1. Fluorescein stain 2. Lissamine green 3. Rose Bengal stain
What is the earliest change in glaucoma on perimetry?
INI-CET 2023 - Ophthalmology INI-CET Practice Questions and MCQs
Question 21: Identify the correct sequence of staining in dry eyes? 1. Fluorescein stain 2. Lissamine green 3. Rose Bengal stain
- A. i, iii, ii
- B. i, ii, iii
- C. ii, iii, i
- D. iii, ii, i (Correct Answer)
Explanation: ***iii, ii, i*** - The correct order for staining in dry eyes is **Rose Bengal, Lissamine Green, and then Fluorescein**. This sequence minimizes the discomfort and potential interference between the dyes. - **Rose Bengal** and **Lissamine Green** stain devitalized or damaged epithelial cells and mucus, while **Fluorescein** stains areas where the epithelium is absent, indicating corneal or conjunctival abrasions or erosions. *i, iii, ii* - This sequence is incorrect because applying fluorescein first could mask the interpretation of epithelial damage by Lissamine Green or Rose Bengal, as it highlights epithelial defects rather than devitalized cells. - The dyes should be applied in an order that optimizes the visualization of different aspects of ocular surface health. *i, ii, iii* - Applying **Fluorescein** first is generally not recommended as it can spread over the ocular surface and potentially interfere with the specific staining patterns of other vital dyes like Lissamine Green or Rose Bengal. - This order does not follow the standard clinical practice for efficient and accurate dry eye assessment. *ii, iii, i* - While Lissamine Green can be used before Fluorescein, placing Rose Bengal after Lissamine Green but still before Fluorescein is not the optimal sequence. - The standard practice aims to assess different layers or types of damage sequentially for a comprehensive evaluation.
Question 22: What is the earliest change in glaucoma on perimetry?
- A. Complete field loss
- B. Isopter contraction + baring of blind spot (Correct Answer)
- C. Tunnel vision defect
- D. Complete vision loss
Explanation: ***Isopter contraction + baring of blind spot*** - Early glaucomatous damage often manifests as an **isopter contraction**, meaning the **visual field narrows** for a given stimulus intensity. - **Baring of the blind spot** occurs when the isopter for a small target contracts inwards, leaving the physiological blind spot exposed to targets that would normally be seen. *Complete field loss* - This is indicative of **very advanced glaucoma**, representing extensive damage to the optic nerve. - It would be preceded by numerous earlier, more subtle visual field defects. *Tunnel vision defect* - **Tunnel vision** is a severe form of visual field constriction, characteristic of **advanced glaucoma** where only the central field of vision remains. - It is not the earliest change as it implies significant peripheral field loss has already occurred. *Complete vision loss* - **Complete vision loss** in an eye signifies end-stage disease, far beyond the earliest changes seen in glaucoma. - It means there is no light perception, indicating total destruction of the optic nerve fibers.
Pathology
1 questionsWhich of the following is an Anti-apoptotic gene?
INI-CET 2023 - Pathology INI-CET Practice Questions and MCQs
Question 21: Which of the following is an Anti-apoptotic gene?
- A. BAK
- B. BIN
- C. NOX-Q
- D. MCL-1 (Correct Answer)
Explanation: ***MCL-1*** - **MCL-1 (myeloid cell leukemia sequence 1)** is a pro-survival protein belonging to the **Bcl-2 family**, which inhibits apoptosis by binding to and sequestering pro-apoptotic proteins [1]. - Its overexpression is frequently observed in various cancers, contributing to **chemoresistance** and tumor survival [2]. *BAK* - **BAK (Bcl-2 antagonist killer 1)** is a **pro-apoptotic protein** that belongs to the Bcl-2 family. - Upon activation, BAK undergoes **oligomerization** on the mitochondrial outer membrane, leading to its permeabilization and the release of pro-apoptotic factors into the cytoplasm. *BIN* - **BIN1 (Bridging Integrator 1)** is a **tumor suppressor gene** that can promote apoptosis in certain contexts, particularly when associated with DNA damage or cellular stress. - It is not primarily known as an anti-apoptotic gene but rather as a protein involved in **membrane dynamics** and cellular signaling, with roles in endocytosis and cytoskeletal regulation. *NOX-Q* - **NOX-Q** is not a commonly recognized or established gene in the context of apoptosis regulation. - The **NOX (NADPH oxidase) family** of enzymes is primarily involved in the production of **reactive oxygen species (ROS)**, which can either induce or inhibit apoptosis depending on the cellular context and concentration. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, p. 310. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 310-311.
Physiology
1 questionsJAK-STAT pathway is seen in which of the following?
INI-CET 2023 - Physiology INI-CET Practice Questions and MCQs
Question 21: JAK-STAT pathway is seen in which of the following?
- A. Calcitonin
- B. Aldosterone
- C. Vasopressin
- D. Leptin (Correct Answer)
Explanation: ***Leptin*** - **Leptin** binding to its receptor activates the **JAK-STAT pathway**, regulating appetite and metabolism. - This pathway involves the phosphorylation of **STAT proteins**, which then translocate to the nucleus to induce gene expression. *Calcitonin* - **Calcitonin** activates **G protein-coupled receptors**, leading to an increase in intracellular cyclic AMP (cAMP). - Its primary role is in **calcium homeostasis**, lowering blood calcium levels. *Aldosterone* - **Aldosterone** is a steroid hormone that binds to **intracellular mineralocorticoid receptors**. - This complex then acts as a **transcription factor**, affecting gene expression in the kidneys to regulate sodium and potassium balance. *Vasopressin* - **Vasopressin** (ADH) binds to **G protein-coupled receptors** (V1 and V2 receptors). - V2 receptor activation in the kidney leads to increased **cAMP** and insertion of aquaporins, regulating water reabsorption.
Surgery
2 questionsA 30-year-old male undergoes varicocele surgery to correct his left-sided varicocele. Following the procedure, the surgeon explains the postoperative changes to the patient. The patient asks, "Through which route does the venous drainage primarily occur after the surgery?" Which of the following is the correct response by the surgeon?
A patient presents with dull aching pain and tortuous veins in both lower limbs. Which test would be appropriate for evaluating saphenofemoral junction (SFJ) incompetence?
INI-CET 2023 - Surgery INI-CET Practice Questions and MCQs
Question 21: A 30-year-old male undergoes varicocele surgery to correct his left-sided varicocele. Following the procedure, the surgeon explains the postoperative changes to the patient. The patient asks, "Through which route does the venous drainage primarily occur after the surgery?" Which of the following is the correct response by the surgeon?
- A. Cremasteric and deferential veins (Correct Answer)
- B. Penile veins
- C. Ectopic drainage in the iliac fossa
- D. At the usual location
Explanation: ***Cremasteric and deferential veins*** - After varicocele surgery, the **internal spermatic veins** (pampiniform plexus) are ligated or embolized, eliminating the primary drainage route. - Venous drainage then shifts to **collateral pathways**: the **cremasteric veins** (which drain to the inferior epigastric vein) and the **deferential/vasal veins** (which drain to the vesical venous plexus). - These provide adequate alternative venous outflow from the testis, preventing venous congestion post-operatively. - This is a well-established anatomical principle in varicocele surgery. *Penile veins* - Penile veins primarily drain the **penis** itself (corpus cavernosum and spongiosum), not the testis. - They are anatomically distinct from the testicular venous drainage system and do not serve as a collateral route after varicocele repair. *Ectopic drainage in the iliac fossa* - This is not a recognized anatomical pathway for testicular venous drainage. - While cremasteric veins eventually drain to the external iliac system via inferior epigastric veins, referring to this as "ectopic drainage in the iliac fossa" is anatomically imprecise and not standard terminology. *At the usual location* - The usual pre-operative drainage is through the **pampiniform plexus → internal spermatic vein** (left side drains to left renal vein, right side to IVC). - This is the pathway that is **surgically interrupted** during varicocele repair (ligation or embolization). - Post-operatively, drainage cannot occur at this location as these vessels are deliberately occluded.
Question 22: A patient presents with dull aching pain and tortuous veins in both lower limbs. Which test would be appropriate for evaluating saphenofemoral junction (SFJ) incompetence?
- A. Fegan's test
- B. Brodie Trendelenburg test (Correct Answer)
- C. Modified Perthes test
- D. Morrissey test
Explanation: ***Brodie Trendelenburg test*** - This test evaluates **venous valve competence** at the saphenofemoral junction (SFJ) by observing the rate of venous refilling after emptying the superficial veins in the supine position and then standing. - Quick refilling of veins upon standing, particularly after compression of the SFJ, suggests **SFJ incompetence**. *Fegan's test* - This test is used to locate **incompetent perforating veins** by palpating for defects in the fascia after emptying the veins and applying compression. - It does not directly assess the competence of the saphenofemoral junction. *Modified Perthes test* - The Perthes test assesses the **patency of deep veins** and the competence of perforating veins by observing the disappearance of superficial veins during exercise with a tourniquet applied. - It primarily differentiates between superficial and deep venous insufficiency, not specifically SFJ incompetence. *Morrissey test* - This test (also known as the percussion test) involves percussing an incompetent vein distally and palpating proximally to detect a transmitted thrill, indicating **venous incompetence**. - While it helps identify reflux, it is less specific for SFJ incompetence compared to the Brodie Trendelenburg test.