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Young mice tolerate myocardial loss after coronary artery ligation (CAL) without congestive heart failure (CHF) signs or mortality. We predicted a CHF phenotype after CAL in aged mice. Left coronary artery ligation produced permanent myocardial infarcts (MI). Mortality was higher in male 14-mo-old C57BL/6N mice (Older mice) than in 2-mo-old mice (Young mice) (16 of 25 Older mice died vs. 0 of 10 Young mice, P < 0.02). After 8 wk, rales, weight loss, and lethargy preceded deaths. Captopril (50 mg x kg(-1) x day(-1)) increased Older mouse survival (6 of 22 died, P < 0.02). Captopril improved systolic function (peak aortic blood velocity) from 76 +/- 6% of baseline in untreated Older mice to 93 +/- 8% (P < 0.036). At 24 h, MI comprised 28 +/- 4% of the left ventricle in Young mice, surprisingly larger than that in Older mice (18 +/- 2%, P < 0.011). Endocardial area underlying the infarct scar was significantly larger in Older mice than in Young mice. Captopril did not reduce expansion but markedly reduced septal hypertrophy. Aging reduces compensatory ability in mice despite smaller acute infarcts. Less effective myocardial repair, greater infarct expansion, and septal hypertrophy are seen with aging. Aging is a more relevant murine model of post-MI heart failure in patients.

The technical performance of five selected commercial photochromic dyes applied by screen-printing on textiles was evaluated using a colour measurement methodology that has previously been established and validated. The results of wash fastness assessments were distinctly unusual. With the selected spirooxazine dyes, the degree of photocoloration increased with initial washing and decreased with subsequent washings, while the naphthopyrans behaved more normally, showing a consistent marginal decrease in photocoloration with repeated washing. An explanation is proposed consistent with scanning electron microscopy examination of the binder film degradation and with the structural differences between the dye classes. The dyes in this application showed limited photostability. The incorporation of ultraviolet absorbers was found to increase photostability only to an extent specific to particular ultraviolet absorber ⁄ dye combinations. However, the presence of the ultraviolet absorber led to a consistent reduction in the degree of photocoloration of the dyes. In contrast, the incorporation of hindered amine light stabilisers significantly enhanced the photostability of the dyes, providing an increase in resistance to photodegradation of up to fivefold.