5 NEW High yield topics for upcoming entrance examinations-27-10-14 1)Taxanes 2)Melanoma 3)Ebola virus 4) CARCINOMA OF UNKNOWN PRIMARY 5) Familial Hemolytic Uremic Syndrome (HUS) 1)*The taxanes are paclitaxel and docetaxel. It differs from the vinca alkaloids in that the taxanes stabilize microtubules against depolymerization. It is used in ovarian cancer, breast cancer, Kaposis sarcoma, and lung tumors. It is administered intravenously. Toxicity includes neurotoxicity, asymptomatic bradycardia, bronchospasm, dyspnea, alopecia and hypotension. It can also cause a vascular leak syndrome and skin discoloration. * Resistance to taxanes has been related to the emergence of mdr gene product or the presence of variant or mutant forms of tubulin. * Epothilones is a novel microtubule-stabilizing agents for activity in taxane-resistant tumors-eg-Ixabepilone (????? AIIMS -2015) is used in breast cancers resistant to taxanes and anthracyclines such as doxorubicin. Side effects, include myelosuppression, and peripheral sensory neuropathy. 2)Melanoma * Melanoma is the most common primary tumor of eye**. It presents with photopsia, enlarging scotomas, loss of vision. Sunscreens decrease the risk of actinic keratoses, the precursor to squamous cell skin cancer, but melanoma risk may be increased. Risk factors for melanoma are a propensity to sunburn, a large number of benign melanocytic nevi and atypical nevi. Two-thirds of melanomas and 10% of colon cancers have activating mutations in the BRAF oncogene. Men are affected more than women (1.3:1), and the median age at diagnosis is the late fifties.* The single greatest risk factor for melanoma is a personal history of melanoma. CDKN2A mutation and MC1R variants are associated. The melanocortin-1 receptor (MC1R) gene is also an inherited melanoma susceptibility factor 3) Ebola vairus * Viral Hemorrhagic Fevers-Caused by four major groups of viruses.(ALL INDIA-2009***) .Arenaviridae (e.g., Lassa fever), Bunyaviridae (e.g., Rift Valley fever, hantavirus hemorrhagic fever with renal syndrome ), Filoviridae (e.g., Ebola and Marburg virus infections), and Flaviviridae (e.g., yellow fever and dengue). * Lassa fever and Ebola and Marburg virus infections - also transmitted from person to person.It is a negative strand RNA virus. Filamentous (negatively stained) virions were fused together, end-to-end, giving the appearance of a bowl of spaghetti’ in ebola virus.*** Both Marburg virus and Ebola virus are biosafety level 4 pathogens. The incubation period is 7–10 days. ELISA is a sensitive diagnostic modality. An adenovirus-vectored Ebola glycoprotein gene is in phase 1 trial. The natural reservoir of Ebola virus is believed to be bats and it is primarily transmitted between humans and from animals to humans through body fluids. There are two candidates for host cell entry proteins. The first is a cholesterol transporter protein, the host-encoded Niemann–Pick C1 (NPC1) and the next is TIM-1. 4) CARCINOMA OF UNKNOWN PRIMARY * The commonest histology is Well to moderately differentiated adenocarcinoma * It is differentiated by cytokeratin (CK7 and CK20) markers. CK20 + / CK7 – strongly suggest a primary tumor of the colon. Markers for mesothelioma are Calretinin, Wilms tumor gene-1 (WT-1), and mesothelin. * Thyroid transcription factor 1 (TTF-1) is present during embryogenesis in the thyroid, diencephalon, and respiratory epithelium. TTF-1 nuclear staining is typically positive in lung and thyroid cancers. 68% of adenocarcinomas and 25% of squamous cell lung cancers stain positive for TTF-1. 5) Familial Hemolytic Uremic Syndrome (HUS) * Mutations in any one of several genes encoding complement regulatory proteins: complement factor H (CFH), CD46 or membrane cofactor protein (MCP), complement factor I (CFI), complement component C3, complement factor B (CFB), and thrombomodulin could be the cause.
Posted on: Mon, 27 Oct 2014 18:33:04 +0000
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