Mnemonic: HALD
Mnemonic: BOHR
Antigenic Drift Nature of antigenic variation: Minor Mechanism: Gradual accumulation of amino acid substitutions due to point mutation in the hemagglutinin (H) and neuraminidase (N) genes. As mutations accumulate, antibodies generated by exposure to previous strains do not neutralize current strains to the same extent, resulting in only limited or…
Endomeatal (Transcanal or Transmeatal) Approach: Not used commonly in children owing to relatively small ear canal This incision is used when the mesotympanum and hypotympanum are the surgical sites A posterior tympanomeatal flap is raised to enter into the middle ear. The flap includes skin over the medial two-thirds of the bony…
Adenoma-carcinoma sequence is a stepwise development of normal epithelium to carcinoma due to accumulation of mutations over a number of years leading to activation of oncogenes and loss of tumor suppressor genes. One of the pathways follows adenoma–carcinoma sequence, that is, normal → adenoma → carcinoma. The other is pertaining…