Leg autotomy in a spider has minimal costs in competitive ability and development.

A number of species have the ability to autotomize limbs voluntarily, but animals that have lost limbs often face substantial costs. We examined the frequency of leg loss and its effects on competitive ability and development in the spider Holocnemus pluchei (Araneae: Pholcidae), a family of spiders known for its readiness to autotomize legs. Leg loss was common in field populations, with 7.5% of all surveyed spiders missing at least one leg, most commonly one of the anterior pair. More spiders were missing multiple legs than expected by chance, suggesting that leg loss events are not independent. Large adult spiders were missing legs more frequently than were small spiders. The competitive ability of injured males was tested in three contexts. In the field, no effect of leg loss was found on the ability of spiders to remain in webs into which they were introduced. In the laboratory, no effect of leg loss was found on the ability to fight with a single opponent over a prey, except that injured spiders were more likely to lose high-intensity fights. There was no difference between intact and injured males in their ability to compete with three females for limited prey. Leg loss significantly affected development time. The moult interval during the instar in which the injury occurred increased by approximately 15%. However, the growth rate for injured spiders was slightly but not significantly faster in the instar following leg loss, and total development time of the two instars together did not differ significantly between treatments. No spider showed any signs of regeneration. We conclude that, although there were some statistically significant differences between intact and injured males, these are unlikely to have major impacts on fitness, in contrast to findings in other species. Copyright 1999 The Association for the Study of Animal Behaviour.

Successful Coronary Interventions Performed with Argatroban Anticoagulation in Patients with Heparin-Induced Thrombocytopenia and Thrombosis Syndrome.

Patients with heparin-induced thrombocytopenia and thrombosis syndrome (HITTS) frequently have coincident vascular disease. Patients with HITTS who require vascular procedures have often been excluded from vascular intervention because intravascular procedures require heparin. Re-exposure to heparin places these patients at great risk for reactivation of thrombosis related to HIT antibody. We present our initial experience with an alternative anticoagulant to heparin, argatroban in patients with HIT antibody who underwent 14 coronary interventions. All 14 coronary lesions were treated successfully and no patient suffered an HITTS-related or an argatroban-related complication.

Percutaneous Transluminal Coronary Angioplasty for Unstable Angina: Predictors of Outcome in a Multicenter Study.

Background: Angiographic and clinical studies have demonstrated that coronary artery plaque rupture with thrombus formation, spasm, or both are frequently responsible for the syndrome of unstable angina. Percutaneous transluminal coronary angioplasty (PTCA) is commonly used in the treatment of patients with coronary artery disease and unstable angina. A number of studies have shown, however, that intracoronary thrombus increases the risk of abrupt vessel closure. The purpose of this study was to define preprocedural variables predictive of the outcome of PTCA performed on patients with unstable angina in a prospective multicenter study using a core angiographic laboratory. Methods and Results: A total of 386 patients with unstable angina underwent coronary angioplasty of 487 lesions treated with balloon PTCA at 9 medical centers. Multivessel or left main coronary artery diseasewas present in 55% and recent myocardial infarction in 22%. Clinical success was achieved in 317 of 386 patients (82.1%), as defined by <50% residual stenosis at every target lesion evaluated in the core angiographic laboratory and no major complication during hospitalization. Major complications (death, Q-wave or non-Q-wave myocardial infarction, or emergency coronary artery bypass surgery) occurred in 36 patients (9.3%), and abrupt vessel closure occurred in 50 (13.0%). Logistic regression analysis identified preprocedural variables that were predictive of outcome of angioplasty. Strong predictors of any complication (major complication or abrupt vessel closure) included age [odds ratio (OR) = 1.04; 95% confidence interval [CII 1.02. 1.071) for each additional year of age; p < 0.001), number of diseased vessels (OR = 1.58; 95% Cl = 1.16, 2.15 per additional vessel; is = 0.012), the number of le~ions treated at angioplasty (OR) = 1.04%; 95% confidence interval [CI] 1.02, 1.07]) for each additional year of age; p < 0.001), number of diseased vessels (OR = 1.58%; 95% CI = 1.16, 2.15 per additional vessel; p = 0.012), the number of lesions treated at angioplasty (OR = 1.72%; 95% CI = 1.11, 2.66;; p = 0.014), and angiographic evidence of filling defect preceding angioplasty (OR = 3.30; 95% CI = 1.11, 9.75; p < 0.001). Conclusions: The outcome of PTCA performed for unstable angina is influenced by a combination of clinical, angiographic, and procedural variables. This study suggests that PTCA performed on lesions associated with filling defects or on more than one lesion at the time of the procedure carries an increased risk of complication. The outcome of PTCA for unstable angina may be improved by identifying new strategies for the treatment of lesions associated with filling defects and by using more accurate methods to identify and treat the culprit lesion responsible for unstable angina.