Pathology

Step 1: Different types of grafts.
- Autograft: Tissue transferred from one site to another within the same individual.
- Isograft: Tissue graft between two genetically identical individuals (e.g., identical twins).
- Allograft: Tissue graft between two genetically different individuals of the same species.
- Xenograft: Tissue graft between two different species.
Step 2: Identification.
The question specifies “genetically identical person” which refers to identical twins.
This type of graft is called an isograft.
Step 3: Conclusion.
Therefore, the correct answer is Isograft.

Step 1: Recall pituitary adenomas.
Pituitary adenomas are classified according to the predominant hormone secreted. They can be functional (hormone-secreting) or non-functional.
Step 2: Understand lactotroph adenomas.
Lactotroph adenomas are prolactin-secreting pituitary tumors. They are the most common type of pituitary adenoma and result in hyperprolactinemia.
Clinical features include galactorrhea, amenorrhea, infertility, and hypogonadism.
Step 3: Analyze the options.
- (A) Growth hormone: Marker for somatotroph adenomas, not lactotrophs.
- (B) -TSH: Marker for thyrotroph adenomas.
- (C) ACTH: Marker for corticotroph adenomas.
- (D) Prolactin: Correct marker for lactotroph adenoma.
Step 4: Conclusion.
The immune marker for lactotroph adenoma is Prolactin.

Step 1: Initial clot formation.
The process begins with the formation of a blood clot in the blood vessels (C).
Step 2: Movement of clot.
The clot then travels to the brain via circulation (A).
Step 3: Effect on brain cells.
Due to ischemia, brain cells begin to undergo lysis as they are deprived of oxygen and nutrients (D).
Step 4: Systemic response.
In response, blood pressure increases (B), putting extra stress on cerebral vessels.
Step 5: Final outcome.
Eventually, the blood vessels rupture (E), leading to haemorrhagic transformation.
Step 6: Conclusion.
The correct sequence is C A D B E.

Step 1: Recall tissue processing steps.
Tissue processing prepares biological tissues for microscopic examination. The goal is to preserve the tissue structure and allow infiltration of embedding medium (paraffin).
Step 2: Sequence of steps.
1. Dehydration: Removal of water from tissues using increasing concentrations of alcohol.
2. Clearing: Replacement of alcohol with a clearing agent (e.g., xylene) which makes tissue transparent.
3. Infiltration: Embedding medium (e.g., paraffin wax) penetrates the tissue.
Step 3: Exclude incorrect orders.
- (A) Clearing first is impossible since dehydration must precede it.
- (B) Infiltration before clearing is not correct.
- (C) Infiltration before dehydration is not possible.
- (D) Correct order = Dehydration → Clearing → Infiltration.
Step 4: Conclusion.
The correct sequence is Dehydration, Clearing, Infiltration.

Step 1: Understanding Hashimoto’s thyroiditis.
Hashimoto’s disease is an autoimmune thyroid disorder in which the immune system attacks the thyroid gland, leading to hypothyroidism.
Step 2: Autoantibodies involved.
The most common antibodies found in Hashimoto’s are:
- Anti-thyroglobulin antibodies (Anti-Tg).
- Anti-thyroid peroxidase antibodies (Anti-TPO).
These antibodies damage the thyroid tissue and impair hormone production.
Step 3: Analyzing options.
- (A) Thyroglobulin: Correct, as anti-thyroglobulin antibodies are hallmark of Hashimoto’s.
- (B) TSH Receptor: Seen in Graves’ disease, not Hashimoto’s.
- (C) Myelin Basic Protein: Seen in multiple sclerosis, not Hashimoto’s.
- (D) Intrinsic Factor: Associated with pernicious anemia, not Hashimoto’s.
Final Answer:

Step 1: Understanding types of transplant rejection.
There are three main types of rejection: hyperacute, acute, and chronic.
- Hyperacute rejection occurs immediately within minutes to hours.
- Acute rejection occurs within days to weeks.
- Chronic rejection develops slowly over months to years.
Step 2: Pathophysiology of chronic rejection.
Chronic rejection involves progressive loss of graft function due to continuous immune-mediated injury, fibrosis, vascular thickening, and ischemia. This is not a sudden process but a slow, long-term deterioration.
Step 3: Identifying correct answer.
Since the question specifically asks for chronic rejection, the correct time frame is months or years.
Final Answer:

Step 1: Recall wound healing types.
Wound healing occurs either by primary intention (clean wounds with edges approximated) or by secondary intention (large tissue loss, wound left open, requiring granulation tissue formation). Healing by secondary intention is slower and leaves more scar tissue.
Step 2: Sequence of events in secondary intention.
1. Initial hemorrhage (B): Immediately after injury, bleeding occurs leading to clot and fibrin deposition.
2. Inflammatory phase (A): Neutrophils and macrophages infiltrate the wound to remove debris and pathogens. This phase is crucial for cleaning the wound.
3. Granulation tissue formation (C): Fibroblasts proliferate, new capillaries grow, and granulation tissue fills the wound gap.
4. Wound contraction (D): Myofibroblasts contract the wound margins, reducing the size of the defect.
5. Epithelial changes (E): Finally, epithelialization occurs, covering the wound surface and completing the healing process.
Step 3: Analyze the options.
- Option (A) B, A, E, C, D: Incorrect sequence, epithelialization does not occur before contraction.
- Option (B) B, E, A, C, D: Incorrect sequence, epithelialization cannot occur immediately after hemorrhage.
- Option (C) B, A, C, D, E: Correct order of events.
- Option (D) B, A, C, E, D: Incorrect, epithelialization occurs at the end.
Step 4: Conclusion.
The correct sequence in secondary intention healing is Initial Hemorrhage → Inflammatory Phase → Granulation Tissue → Wound Contraction → Epithelial Changes.

Step 1: Role of complement system.
The complement system is an essential part of innate immunity. Genes like CFH (complement factor H), C2, C3, and CFB regulate complement activation. Mutations or polymorphisms in these genes disturb regulation and predispose to chronic inflammatory conditions.
Step 2: Disease association.
- Mutations in CFH, C2, C3, and CFB are strongly associated with age-related macular degeneration (AMD).
- This is because abnormal complement activation leads to chronic inflammation and deposition of drusen in the retina.
Step 3: Eliminating other options.
- (A) MBL deficiency: Involves MBL2 gene, not CFH, C2, C3, or CFB.
- (C) Paroxysmal nocturnal haemoglobinuria: Caused by PIGA gene defect affecting GPI-anchor proteins.
- (D) Hereditary angioedema: Caused by C1 esterase inhibitor deficiency, not by CFH or C3.
Final Answer:

Step 1: Recall principle of antigen-antibody reactions.
Antigen-antibody reactions include agglutination, precipitation, ELISA, complement fixation, and immunofluorescence. These tests are vital for diagnosis of infectious diseases and immune disorders.
Step 2: Match with lab departments.
- Hematology: Deals with blood cells, coagulation studies, not antigen-antibody reactions.
- Microbiology: Identifies microbes, sometimes uses antigen detection, but not the central lab for immune reactions.
- Biochemistry: Analyzes metabolic products, enzymes, hormones, not immune testing.
- Immunology: Specializes in antigen-antibody reactions, autoimmune testing, allergy testing, and vaccine response.
Step 3: Conclusion.
The correct department for antigen-antibody reactions is Immunology.

Step 1: Recall pathogenesis of oedema.
Oedema is abnormal accumulation of fluid in interstitial tissues. It results from imbalance of Starling forces and lymphatic drainage.
Step 2: Causes of oedema.
1. Decreased plasma oncotic pressure (A): Seen in hypoalbuminemia due to malnutrition, nephrotic syndrome, or liver disease. This reduces the pull of fluid back into capillaries.
2. Increased capillary permeability (B): Occurs in inflammation, burns, or allergy. Plasma proteins leak out, increasing fluid shift into tissues.
3. Obstruction of lymphatic drainage (D): Seen in filariasis, tumor compression, or surgical removal of lymph nodes. Prevents removal of interstitial fluid.
Step 3: Exclude wrong causes.
- (C) Increased plasma oncotic pressure: Does not cause oedema; it would prevent it.
- (E) Decreased capillary permeability: Not a cause of oedema; instead, it reduces fluid leakage.
Step 4: Conclusion.
The correct answer is A (Decreased plasma oncotic pressure), B (Increased capillary permeability), and D (Obstruction of lymphatic drainage).

Step 1: Recall sweat gland anatomy.
Sweat glands are exocrine glands present in the skin and are of two main types: eccrine and apocrine. Eccrine glands are distributed widely and play an important role in thermoregulation. Apocrine glands are localized in axilla, groin, and perineum.
Step 2: Tumors arising from sweat glands.
Neoplasms can originate from the cells of sweat glands. The most commonly recognized benign and malignant tumors are related to eccrine glands, hence called eccrine tumors. Examples include syringoma (benign), eccrine poroma, and eccrine carcinoma (malignant).
Step 3: Eliminate wrong options.
- (B) Dermatofibroma: This is a benign tumor of fibroblasts in the dermis, unrelated to sweat glands.
- (C) Pleomorphic Sarcoma: A soft tissue sarcoma, not a sweat gland tumor.
- (D) Mycosis Fungoides: A cutaneous T-cell lymphoma, not arising from sweat glands.
Step 4: Conclusion.
The correct answer is Eccrine Tumor, which is a tumor of sweat gland origin.

Concept: Hemoglobin estimation is an important laboratory test used to measure the concentration of hemoglobin in blood. Different methods are based on converting hemoglobin into specific derivatives that can be measured colorimetrically. In the Haldane Method, hemoglobin combines with carbon monoxide to form carboxyhemoglobin, which produces a stable color that can be measured.
Step 1: Identify the method where hemoglobin forms carboxyhemoglobin.

• Sahli's Method – Converts hemoglobin to acid hematin.
• Cyanmethemoglobin Method – Converts hemoglobin to cyanmethemoglobin.
• Haldane Method – Converts hemoglobin to carboxyhemoglobin.
• Tallqvist Method – Visual color comparison method.

Thus, the method in which hemoglobin is converted into carboxyhemoglobin is the Haldane Method.