ABSTRACT
Near-field scanning optical microscopy and atomic force microscopy are used to probe the sub-micrometre phase structure in palmitic acid monolayers containing the 25 peptide amino terminus of lung surfactant protein B (SP-B(1-25)). Monolayers deposited onto mica substrates at a surface pressure of 15 mN m-1 exhibit a two-phase coexistence across a broad range of SP-B(1-25) concentrations. Monolayers containing 5 wt.% SP-B(1-25) or less exhibit an expanse of liquid condensed phase in which elliptical liquid expanded (LE) domains with areas of approximately 25 microm2 coexist. By contrast, monolayers containing 20 wt.% SP-B(1-25) exhibit an expanse of liquid expanded phase in which circular liquid condensed domains coexist. The phase distribution dependence on SP-B(1-25) concentration suggests that the peptide induces disorder in the monolayer.
Subject(s)
Palmitic Acid/chemistry , Proteolipids/ultrastructure , Pulmonary Surfactants/ultrastructure , Amino Acid Sequence , Microscopy/methods , Microscopy, Atomic Force , Molecular Sequence Data , Proteolipids/chemistry , Pulmonary Surfactants/chemistryABSTRACT
A retrospective study of the work status of 45 consecutive male patients who were at least 12 months post myocardial infarction was carried out. The vast majority of patients were in the lower socioeconomic classes. Only 31 percent of those previously working returned to employment. No differences were found in mean age, physical disability, or anxiety; however, those not working were significantly more depressed (P < .05). A major factor related to failure to return to work may be that the majority of this lower socioeconomic group of patients worked as laborers and did not have the education or training to find alternative jobs.
