Atelectasis Leakage of air into the pleural cavity (pneumothorax) also leads to compression atelectasis. It occurs when either local or generalized fibrotic changes in the lung or pleura hamper expansion and increase elastic recoil during expiration. Causes include granulomatous disease, necrotising pneumonia and radiation fibrosis. Chronic atelectasis may take one of two forms—middle lobe syndrome or rounded atelectasis. In right middle lobe syndrome, the middle lobe of the right lung contracts, usually because of pressure on the bronchus from enlarged lymph glands and occasionally a tumor. The blocked, contracted lung may develop pneumonia that fails to resolve completely and leads to
Albinism in humans of melanocyte tyrosinase enzymes, a change that is hypothesized to promote brown versus black melanin synthesis, resulting in a third oculocutaneous albinism (OCA) genotype, ″OCA3″. Some rare forms are inherited from only one parent. There are other genetic mutations which are proven to be associated with albinism. All alterations, however, lead to changes in melanin production in the body. Some of these are associated with increased risk of skin cancer . The chance of offspring with albinism resulting from the pairing of an organism with albinism and one without albinism is low. However, because organisms (including humans) can be carriers