How blue are British tits? Sex, age and environmental effects

Capsule The blue colour of the coverts and crowns of Blue Tits Cyanistes caeruleus and Great Tits Parus major is influenced by sex, age and environmental factors. Aims To quantify the blueness of two species of tits breeding in different habitats in Britain. Methods By manipulating daylength in the laboratory, adult Blue Tits were induced to moult at fast and slow speeds. When they had finished, the blue colour of their wing coverts and crowns was measured (in the range visible to human observers), and compared with the colour of birds caught in the field. Results As well as highly significant sex and age differences in colour, Blue Tits were 26% bluer in 1998 than 2000, and male Great Tits were 15% less blue in small woods than in large woods in our study population in East Anglia, England. Both species became more saturated with blue up to the age of three years. British Cy. c. obscurus were darker blue than Cy. c. caeruleus of Continental Europe . Conclusions There are significant environmental influences on the blueness of British tits in addition to the well-known age and sex effects

The mechanisms of coronary restenosis: insights from experimental models

Since its introduction into clinical practice, more than 20 years ago, percutaneous transluminal coronary angioplasty (PTCA) has proven to be an effective, minimally invasive alternative to coronary artery bypass grafting (CABG). During this time there have been great improvements in the design of balloon catheters, operative procedures and adjuvant drug therapy, and this has resulted in low rates of primary failure and short-term complications. However, the potential benefits of angioplasty are diminished by the high rate of recurrent disease. Up to 40% of patients undergoing angioplasty develop clinically significant restenosis within a year of the procedure. Although the deployment of endovascular stents at the time of angioplasty improves the short-term outcome, ‘in-stent’ stenosis remains an enduring problem. In order to gain an insight into the mechanisms of restenosis, several experimental models of angioplasty have been developed. These have been used together with the tools provided by recent advances in molecular biology and catheter design to investigate restenosis in detail. It is now possible to deliver highly specific molecular antagonists, such as antisense gene sequences, to the site of injury. The knowledge provided by these studies may ultimately lead to novel forms of intervention. The present review is a synopsis of our current understanding of the pathological mechanisms of restenosis