Anatomy
1 questionsUreteric bud develops from:
NEET-PG 2018 - Anatomy NEET-PG Practice Questions and MCQs
Question 31: Ureteric bud develops from:
- A. Mesonephros (Correct Answer)
- B. Metanephros
- C. Pronephros
- D. Genital sinus
Explanation: ***Mesonephros*** - The **ureteric bud** arises as an outgrowth of the **mesonephric duct** (Wolffian duct), which is the duct of the mesonephros. - The ureteric bud emerges from the **caudal portion of the mesonephric duct** near its entry into the cloaca around the 5th week of development. - It plays a crucial role in forming the **collecting system of the kidney**, including the ureter, renal pelvis, major and minor calyces, and collecting ducts. - **Note:** While technically the ureteric bud arises from the mesonephric duct (not the mesonephric tubules), "mesonephros" is accepted as the answer referring to the mesonephric duct system. *Metanephros* - The **metanephric mesoderm** (metanephric blastema) is induced by the ureteric bud to form the **definitive kidney**. - The metanephros forms the **nephrons** (from Bowman's capsule to distal convoluted tubule). - It does not give rise to the ureteric bud; rather, it interacts with it through **reciprocal induction**. *Pronephros* - The **pronephros** is the first, transient, and **non-functional** kidney structure in human embryonic development. - It appears in the **cervical region** around week 4 and completely **regresses** by week 5. - It does not contribute to the formation of the ureteric bud or the adult kidney. *Genital sinus* - The **urogenital sinus** is derived from the ventral part of the cloaca after division by the urorectal septum. - It gives rise to the **bladder**, parts of the urethra, and contributes to external genitalia. - It is not involved in the development of the ureteric bud or the kidney's collecting system.
Biochemistry
2 questionsTrilene is degraded by:
Which of the following is an example of an X-linked disorder?
NEET-PG 2018 - Biochemistry NEET-PG Practice Questions and MCQs
Question 31: Trilene is degraded by:
- A. Glutathione conjugation
- B. Cytochrome P450 oxidation (Correct Answer)
- C. Direct renal excretion
- D. Acetylation
Explanation: ***Cytochrome P450 oxidation*** - **Trichloroethylene (Trilene)** was historically used as an inhalational anesthetic and industrial solvent - In humans, it undergoes **hepatic metabolism primarily through cytochrome P450 enzymes**, particularly **CYP2E1** - The oxidation pathway produces metabolites including **chloral hydrate, trichloroethanol, and trichloroacetic acid** - This is a classic example of **Phase I detoxification** involving oxidative biotransformation - The metabolites are then conjugated (Phase II) or excreted renally *Glutathione conjugation* - While some chlorinated compounds undergo glutathione conjugation as a Phase II reaction - For trichloroethylene, **oxidation by CYP450 is the primary metabolic pathway**, not direct glutathione conjugation - GSH conjugation may occur with some metabolites but is not the main degradation route *Direct renal excretion* - Trilene is **lipophilic** and requires hepatic metabolism before elimination - Direct renal excretion without biotransformation is **minimal** - Metabolites (after oxidation) are excreted via kidneys *Acetylation* - **Acetylation** is a Phase II conjugation reaction typically for compounds with **amino or sulfonamide groups** - Trichloroethylene lacks the appropriate functional groups for acetylation - This pathway is **not involved** in Trilene metabolism
Question 32: Which of the following is an example of an X-linked disorder?
- A. Color blindness (Correct Answer)
- B. Thalassemia
- C. Azoospermia
- D. Sickle cell anemia
Explanation: ***Color blindness*** - **Color blindness**, particularly red-green color blindness, is a classic example of an **X-linked recessive disorder**. - It results from mutations in genes encoding **photopigments** located on the X chromosome, affecting more males than females. - Represents one of the most commonly cited examples of X-linked inheritance in medical education. *Thalassemia* - **Thalassemia** is an **autosomal recessive disorder** affecting the synthesis of hemoglobin chains (α or β chains). - Not an X-linked condition; mutations are in genes on chromosome 16 (α-thalassemia) or chromosome 11 (β-thalassemia). - Commonly seen in populations from the Mediterranean, Middle East, and Asia. *Azoospermia* - **Azoospermia** (absence of sperm in ejaculate) is a clinical finding, not a specific genetic disorder. - Can result from various genetic causes including **Y-chromosome microdeletions** and **autosomal mutations** (e.g., CFTR gene in congenital bilateral absence of vas deferens). - Not classified as an X-linked disorder. *Sickle cell anemia* - **Sickle cell anemia** is an **autosomal recessive disorder** caused by a mutation in the β-globin gene on chromosome 11. - Results from substitution of valine for glutamic acid at position 6 of the β-globin chain (HbS). - Not an X-linked condition; both males and females are equally affected when inheriting two copies of the mutant allele.
Internal Medicine
1 questionsPatient presenting with cutaneous vasculitis, glomerulonephritis, peripheral neuropathy, Which investigation is to be performed next that will help you diagnose the condition?
NEET-PG 2018 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 31: Patient presenting with cutaneous vasculitis, glomerulonephritis, peripheral neuropathy, Which investigation is to be performed next that will help you diagnose the condition?
- A. ANCA (Correct Answer)
- B. RA factor
- C. Hbsag
- D. MIF
Explanation: ### ANCA - The combination of **cutaneous vasculitis**, **glomerulonephritis**, and **peripheral neuropathy** points towards a small-vessel vasculitis, for which **ANCA (anti-neutrophil cytoplasmic antibodies)** testing is crucial [1]. - ANCA is highly specific for conditions like **Granulomatosis with Polyangiitis (GPA)** and **Microscopic Polyangiitis (MPA)** [1]. ### RA factor - **Rheumatoid factor (RF)** is primarily associated with **rheumatoid arthritis**, which typically presents with symmetrical polyarthritis, not the constellation of symptoms described. - While RF can be positive in some vasculitides, it is not the most specific initial test for the given clinical presentation. ### Hbsag - **Hepatitis B surface antigen (HbsAg)** typically screens for **Hepatitis B infection**, which can cause **polyarteritis nodosa (PAN)**, a medium-vessel vasculitis. - However, the patient's symptoms (cutaneous vasculitis, glomerulonephritis) are more characteristic of **small-vessel vasculitis**, making ANCA a more direct investigation [1]. ### MIF - **MIF (Macrophage Migration Inhibitory Factor)** is a cytokine involved in inflammation, but it is not a routine diagnostic marker for vasculitis. - It is not used as a primary investigation to diagnose specific autoimmune or inflammatory conditions like vasculitis.
Obstetrics and Gynecology
3 questionsWhich of the following methods is known as a fimbriectomy procedure?
Which of the following is not a high-risk pregnancy?
What type of uterine anomaly is shown in this X-ray HSG image?
NEET-PG 2018 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 31: Which of the following methods is known as a fimbriectomy procedure?
- A. Uchida procedure
- B. Irving procedure
- C. Madlener procedure
- D. Kroener procedure (Correct Answer)
Explanation: ***Kroener procedure*** - The **Kroener procedure** is a method of **tubal ligation** particularly known as a **fimbriectomy**, where the fimbriated end of the fallopian tube is removed. - This sterilization technique primarily involves excising the **fimbriae**, preventing **ovum capture** and subsequent fertilization. *Uchida procedure* - The **Uchida procedure** involves **injecting a sclerosing solution** under the serosa of the fallopian tube, then excising a small segment and ligating the ends. - This method aims to **bury the fimbriated end** within the broad ligament, but it is not a fimbriectomy. *Irving procedure* - The **Irving procedure** involves **tying and transecting the fallopian tube**, then burying the severed medial end into the posterior wall of the uterus. - This technique is designed to prevent **fistula formation** and recanalization but does not involve fimbriectomy. *Madlener procedure* - The **Madlener procedure** involves **crushing a section** of the fallopian tube, usually a knuckle, and then ligating it. - This method is simpler but has a **higher failure rate** compared to other sterilization techniques and does not involve removal of the fimbriae.
Question 32: Which of the following is not a high-risk pregnancy?
- A. Age 25-30 years (Correct Answer)
- B. Diabetes mellitus
- C. Previous history of manual removal of placenta
- D. Anemia
Explanation: ***Age 25-30 years*** - An age of **25-30 years** is generally considered the optimal reproductive age range, and pregnancies within this bracket are typically classified as low-risk based on age alone. - This age range carries the lowest statistical risk for both maternal and fetal complications, assuming no other co-morbidities. *Previous history of manual removal of placenta* - A previous history of manual removal of the placenta indicates a risk factor for **recurrent placental retention** or **morbidly adherent placenta** in future pregnancies, making it a high-risk factor. - This history suggests an increased likelihood of complications such as **postpartum hemorrhage** and can influence the management of subsequent deliveries. *Anemia* - **Anemia** in pregnancy, especially severe iron deficiency anemia, is considered a high-risk factor due to increased maternal and fetal morbidity. - It can lead to complications such as **preterm delivery**, **low birth weight**, and difficulties tolerating blood loss during delivery. *Diabetes mellitus* - **Diabetes mellitus**, whether pre-existing or gestational, makes a pregnancy high-risk due to potential adverse effects on both the mother and the fetus. - Risks include **preeclampsia**, **macrosomia**, **neonatal hypoglycemia**, and **congenital anomalies**.
Question 33: What type of uterine anomaly is shown in this X-ray HSG image?
- A. Septate uterus
- B. Uterus didelphys
- C. Unicornuate uterus (Correct Answer)
- D. Bicornuate uterus
Explanation: ***Unicornuate uterus*** - The image shows a single, elongated uterine horn with a single fallopian tube arising from it, consistent with a **unicornuate uterus**. - This congenital anomaly results from the **failure of one Müllerian duct to develop**, leading to an abnormally shaped uterus. *Septate uterus* - A **septate uterus** would show a normal uterine fundus with an internal septum dividing the uterine cavity. - This image clearly depicts only **one rudimentary horn** and no visible septum. *Uterus didelphys* - **Uterus didelphys** involves two completely separate uteri, each with its own cervix and vagina. - The image does not show evidence of a **second, separate uterine structure**. *Bicornuate uterus* - A **bicornuate uterus** is characterized by two distinct uterine horns, which fuse at the cervix or lower uterine segment, creating a heart-shaped appearance of the fundus. - The image shows a **single, long horn** rather than two distinct horns.
Pathology
3 questionsWhich gene is primarily associated with Cowden syndrome?
In which type of Hodgkin's lymphoma are classical Reed-Sternberg cells most characteristically observed?
Warthin-Finkeldey cells are seen in
NEET-PG 2018 - Pathology NEET-PG Practice Questions and MCQs
Question 31: Which gene is primarily associated with Cowden syndrome?
- A. PTEN (Correct Answer)
- B. RB1
- C. KRAS
- D. TP53
Explanation: ***PTEN*** - Cowden syndrome is an **autosomal dominant** inherited disorder caused by germline mutations in the **PTEN (phosphatase and tensin homolog) tumor suppressor gene**. - The PTEN gene plays a crucial role in cell growth, proliferation, and apoptosis, and its dysfunction leads to uncontrolled cell growth and the development of multiple **hamartomas** and increased cancer risk. *TP53* - Mutations in the **TP53 gene** are primarily associated with Li-Fraumeni syndrome, a different inherited cancer predisposition syndrome characterized by a high risk of various cancers including sarcomas, breast cancer, and adrenocortical carcinoma. - While both inherited cancer syndromes involve tumor suppressor gene mutations, the specific gene affected and the clinical presentation differ significantly. *RB1* - The **RB1 gene** is a tumor suppressor gene primarily associated with **retinoblastoma**, a rare childhood eye cancer, and an increased risk of other cancers like osteosarcoma. - It plays a critical role in cell cycle regulation, and its mutation leads to uncontrolled cell division in the retina and other tissues. *KRAS* - The **KRAS gene** is an oncogene, not a tumor suppressor gene, and its mutations are frequently found in various sporadic cancers, particularly **colorectal cancer**, pancreatic cancer, and lung cancer. - KRAS mutations lead to constitutive activation of signaling pathways that promote cell growth and survival, but they are not the primary genetic cause of inherited Cowden syndrome.
Question 32: In which type of Hodgkin's lymphoma are classical Reed-Sternberg cells most characteristically observed?
- A. Lymphocyte depleted
- B. Nodular sclerosis
- C. Lymphocyte predominance
- D. Mixed cellularity Hodgkin (Correct Answer)
Explanation: ***Lymphocyte predominance*** - The **Hodgkin's lymphoma (HL) lymphocyte predominance** variant characteristically displays a predominance of lymphocytes in the cellular makeup [1]. - This subtype is often associated with a better prognosis and fewer symptoms than other types of HL [1]. *Lymphocyte depleted* - This subtype features a significant decrease in lymphocytes, leading to a **higher proportion of Reed-Sternberg cells** [3]. - It typically presents with a more aggressive clinical course, which contrasts with lymphocyte predominance [3]. *Mixed cellularity hodgkin* - Mixed cellularity shows a variety of cell types, including a significant number of **Reed-Sternberg cells**, but does not demonstrate **lymphocyte predominance** [2]. - This subtype is generally found in older patients and associated with advanced disease, unlike lymphocyte predominance [2]. *Nodular sclerosis* - Nodular sclerosis subtype is characterized by **collagen bands** and a particular architecture that is distinct from lymphocyte predominance [2]. - It primarily affects younger patients and can often involve mediastinal lymph nodes; however, it does not have the features of lymphocyte predominance [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 618. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 616-618. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 559-560.
Question 33: Warthin-Finkeldey cells are seen in
- A. Measles infection (Correct Answer)
- B. Rubella infection
- C. Rabies infection
- D. Typhoid infection
Explanation: ***Measles infection*** - **Warthin-Finkeldey cells** are characteristic large, multinucleated giant cells with acidophilic intranuclear and intracytoplasmic inclusions found in lymphoid tissues during the prodromal phase of **measles** [1]. - These cells result from the fusion of measles virus-infected lymphocytes and are a **histological hallmark** of the disease [1]. *Rubella infection* - Rubella, or German measles, typically presents with a milder rash and **arthralgia** in adults. - While it is a viral infection, it does **not characteristically form Warthin-Finkeldey cells** in lymphoid tissue. *Rabies infection* - Rabies is a viral encephalitis primarily affecting the nervous system. - The characteristic histological finding in rabies is the presence of **Negri bodies** (eosinophilic inclusions) in the cytoplasm of neurons, not Warthin-Finkeldey cells in lymphoid tissue. *Typhoid infection* - Typhoid fever is a **bacterial infection** caused by *Salmonella Typhi*. - Histological features include **macrophage hyperplasia** and **typhoid nodules** in lymphoid tissues (like Peyer's patches), but not Warthin-Finkeldey cells. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 362-363.