Pg Blazer - Online Test Series 24 - Pathology

Lipofuscin is a pigment that accumulates in cells as a result of oxidative damage and free radical injury. It is a product of lipid peroxidation and is commonly found in aging cells. Lipofuscin can impair cellular function and contribute to the development of various age-related diseases. Melanin, bilirubin, and hematin are not directly involved in free radical injury. Melanin is responsible for skin and hair color, bilirubin is a breakdown product of hemoglobin, and hematin is a component of hemoglobin.

NPHS 2 is the correct answer because it is the most common gene defect associated with idiopathic steroid resistant nephrotic syndrome. This gene encodes for a protein called podocin, which is essential for maintaining the structure and function of the kidney's filtration system. Mutations in the NPHS 2 gene can disrupt this filtration system, leading to the development of nephrotic syndrome that does not respond to steroid treatment. Therefore, NPHS 2 is the most likely gene defect to be found in individuals with idiopathic steroid resistant nephrotic syndrome.

Adult cells have many cyclin inhibitors that prevent them from entering the S phase of the cell cycle, where DNA replication occurs. This prevents adult cells from dividing. In contrast, fetal cells do not have these inhibitors, allowing them to continue dividing. The absence of phosphatase, proteinase, and CD kinase in fetal cells is not mentioned in the question and therefore cannot be used to explain why fetal cells continue to divide.

Amorphous densities in mitochondria are the most pathognomonic sign of irreversible cell injury. This indicates severe damage to the mitochondria, which are responsible for producing energy in the cell. The presence of amorphous densities suggests a disruption in the normal functioning of the mitochondria, leading to irreversible cell injury. This can occur due to various factors such as toxins, lack of oxygen, or severe cellular stress. The other options mentioned, such as swelling of the cell membrane, ribosomes detached from endoplasmic reticulum, and clumping of nuclear chromatin, may also indicate cell injury but are not as specific or characteristic as the presence of amorphous densities in mitochondria.

Toll-like receptors (TLRs) are a type of protein that recognize bacterial products and initiate an immune response. When TLRs are activated, they trigger the transcription of nuclear factor kappa B (NFKB), which is a transcription factor that regulates the expression of various genes involved in the immune response. One of the genes that NFKB activates is the gene for cytokines, which are signaling molecules involved in inflammation and immune cell recruitment. Therefore, the correct answer is "Transcription of nuclear factor mediated by NFKB which recruits cytokines."

The most probable diagnosis for the tumor is carcinoma because the immunohistochemical stain shows cytoplasmic positivity of most of the tumor cells for cytokeratin. Cytokeratin is a protein that is commonly expressed in epithelial cells, which are the cells that make up the lining of organs and tissues. Carcinomas are malignant tumors that arise from epithelial cells, so the positive staining for cytokeratin suggests that the tumor is likely a carcinoma. Sarcomas, lymphomas, and malignant melanomas are different types of tumors that do not typically show cytoplasmic positivity for cytokeratin.

During acute inflammation, the contraction of endothelial cell cytoskeleton leads to a temporary increase in permeability. This means that there is a brief period where the blood vessels become more permeable, allowing fluid, immune cells, and other molecules to easily pass through the vessel walls and enter the surrounding tissues. This increase in permeability is transient because it is temporary and does not last for a prolonged period.

The condition is probably amyloidosis. Non branching filaments of indefinitive length are seen in amyloidosis.

Eotaxin is a C-C beta chemokine. Chemokines are small proteins that play a crucial role in immune responses by attracting immune cells to the site of infection or inflammation. C-C chemokines, including Eotaxin, are characterized by the presence of two adjacent cysteine residues in their amino acid sequence. Eotaxin specifically attracts eosinophils, a type of white blood cell involved in allergic reactions and asthma. Therefore, Eotaxin is a valid example of a C-C beta chemokine.

The ideal immunohistochemistry panel for this case would include vimentin, epithelial membrane antigen, inhibin, and CD99. Vimentin is a marker for mesenchymal cells and can help determine the origin of the tumor. Epithelial membrane antigen is commonly expressed in epithelial tumors and can help confirm the epithelial nature of the tumor. Inhibin is a marker for sex cord-stromal tumors, which can help narrow down the differential diagnosis. CD99 is a nonspecific marker that can be expressed in various types of tumors, including ovarian tumors. Therefore, this panel of markers would provide valuable information for the diagnosis of the ovarian tumor in this patient.