Sequence and expression of human protein kinase C-epsilon.

Two human homologues of protein kinase C-epsilon (E1 and E2) were isolated from two distinct cDNA libraries. Sequence comparisons to PKC-epsilon cDNAs from several species indicated that each of these human epsilon clones contained cloning artifacts. Thus, a composite PKC-epsilon (E3) clone was derived from clones E1 and E2. Human PKC-epsilon (E3) has an overall sequence identity of 90-92% at the nucleotide level compared to the previously characterized mouse, rat and rabbit clones. At the amino acid level, the deduced human epsilon sequence shows a 98-99% identity with the mouse, rat and rabbit sequences. Expression of the human PKC-epsilon clone in Sf9 cells confirmed that the recombinant protein displayed protein kinase C activity and phorbol ester binding activity. The recombinant protein was also recognized by two distinct epsilon-specific polyclonal antibodies.

Light microscopic and ultrastructural study of the adverse effects of oxygen therapy on the neonate lung.

Alterations of lung tissues were evaluated in 74 infants with respiratory distress who received respirator therapy and high concentrations of oxygen for varying durations. Infant survival ranged from 3 hours to 135 days. Sequential pathologic changes were revealed to be an exudative reaction superimposed upon the early stages of typical hyaline membrane disease. This merged with and was eventually replaced by a reparative fibroproliferative response that was most pronounced in those infants who survived for the longest period of time. This response appeared causally related to the development of pulmonary complications of interstitial fibrosis, emphysema, obliterative bronchiolitis and cystic bronchiolectasis. Correlative ultrastructural studies disclosed generalized capillary endothelial damage in early stages of oxygen therapy, interstitial edema and alteration of alveolar cells attributed to the toxic effects of oxygen. Proliferation of type 2 alveolar cells with incorporation of hyaline membranes into septal walls was a notable feature of the reparative reaction and appeared significant in the subsequent development of interstitial fibrosis.