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pathology - 3 Questions

1
Pathology

All are true regarding Sarcoidosis except -
1. Dry cough
2. Exertional Dyspnoea
3. Wheezing
4. Hemoptysis

📝 Explanation:

Sarcoidosis is a systemic granulomatous disorder of unknown etiology that can affect any organ in the body. It is characterized by the formation of non-caseating granulomas, which are clumps of inflammatory cells that cluster together in response to an unidentified antigen. The lungs and lymph nodes are most commonly involved. Here's a detailed explanation for each of the options:

1. Dry cough: This is a common symptom of pulmonary sarcoidosis. The cough is usually persistent and non-productive, meaning it does not bring up mucus or phlegm. The presence of a dry cough is not contradicted in the statement "All are true regarding Sarcoidosis except," so this option is not the correct answer.

2. Exertional dyspnoea: Shortness of breath on exertion can occur in individuals with pulmonary sarcoidosis due to the inflammation and granuloma formation in the lungs. This symptom can be a result of the impaired lung function and decreased lung capacity caused by the disease. Therefore, this is also a true statement regarding sarcoidosis.

3. Wheezing: Wheezing is a high-pitched whistling sound that occurs during breathing, typically heard when airways become narrowed or blocked. It can be a symptom of pulmonary sarcoidosis, particularly if the disease involves the bronchi and bronchioles, leading to bronchial obstruction and airflow limitation. However, it is not the primary symptom and may be less common than the other respiratory symptoms mentioned.

4. Hemoptysis: While hemoptysis, or coughing up blood, is not a hallmark symptom of sarcoidosis, it can occur in some cases, particularly when the granulomas are located in the lungs. It is usually mild and self-limited, but severe cases can lead to significant bleeding. This is a true statement regarding sarcoidosis, as it is a possible, although less common, respiratory symptom of the disease.

Since all the options (1, 2, and 4) are true regarding Sarcoidosis

2
Pathology

Examples of oncofoetal antigen is/are:
1. -fetoprotein
2. Carcinoembryonic antigen
3. A and B
4. None of the above

📝 Explanation:

Oncofoetal antigens are substances that are normally present in the developing fetus but are found in abnormally high quantities in the tissues of certain cancer cells. These antigens are proteins that can be used as markers for the detection of certain types of cancers. The presence of these antigens in cancer cells suggests that the tumor cells have partially reverted to a more primitive, embryonic stage of development.

Explanation for each option:

1. -Fetoprotein (AFP): This is an oncofoetal antigen. It is a glycoprotein that is produced by the liver cells of the developing fetus. In adults, the production of AFP is usually very low. However, in cases of certain cancers such as hepatocellular carcinoma (primary liver cancer) and some types of testicular cancer, the tumor cells start producing AFP in large amounts. Therefore, high levels of AFP in the blood can be indicative of these cancers.

2. Carcinoembryonic antigen (CEA): CEA is another example of an oncofoetal antigen. It is a glycoprotein that is present in the gastrointestinal tract, pancreas, and sometimes in the respiratory and reproductive systems of a developing fetus. In adults, CEA levels are typically very low. However, in certain types of cancers, such as colorectal cancer, gastric cancer, and some forms of lung, pancreatic, and breast cancer, the tumor cells may start producing large amounts of CEA, which can be detected in the blood and used as a tumor marker for these malignancies.

3. A and B: Both α-fetoprotein and carcinoembryonic antigen are examples of oncofoetal antigens, so this option is correct.

3
Pathology
The opsonins which leads to phagocytosis is/are:
1. lgG (Fc fragment)
2. C3b of complement cascade
3. 1gM (Fc fragment) and C5b of complement cascade
4. A and B

📝 Explanation:

Opsonins are molecules that enhance the phagocytosis of antigens by binding to their surfaces and acting as markers or labels that make them more recognizable to phagocytes.
1. lgG (Fc fragment): Immunoglobulin G (IgG) is the most common antibody isotype in human serum. It plays a crucial role in the secondary immune response. The Fc region of IgG is the fragment that interacts with Fc receptors present on the membrane of phagocytic cells. When an antigen is coated with IgG, the Fc fragments of these antibodies can bind to the Fc receptors, leading to the activation of the phagocytic process. This is known as antibody-dependent phagocytosis, where the antibody acts as an opsonin to facilitate the recognition and engulfment of the antigen by phagocytic cells.

2. C3b of complement cascade: The complement system is a cascade of proteins that can be activated in response to an infection or the presence of foreign substances. C3 is a central protein in this system, and when it is cleaved into C3a and C3b, the latter can bind directly to antigens. C3b acts as an opsonin by coating the surface of pathogens. The presence of C3b on a microbial surface allows it to be recognized by complement receptors on phagocytic cells, such as macrophages. This interaction enhances the efficiency of phagocytosis, as the receptors can recognize the bound C3b and engulf the antigen more readily.

3. IgM (Fc fragment) and C5b of complement cascade: While IgM is the first antibody isotype produced in response to an infection and can also opsonize antigens, it is less efficient than IgG due to its pentameric structure and lower affinity for phagocytic receptors. However, it is not as commonly associated with phagocytosis as IgG. Regarding C5b, it is part of the membrane attack complex (MAC) and is involved in the direct destruction of pathogens rather than acting as a classical opsonin that leads to phagocytosis. The MAC assembles on the surface of the antigen and creates pores, leading to osmotic lysis and destruction of the cell membrane.

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