Quality of life after knee arthroplasty. A randomized study of 3 designs in 42 patients, compared after 4 years

BACKGROUND: An initial multicenter study using a 21 mm flanged esophageal Z stent demonstrated excellent palliation but an 11% immediate complication rate at placement and a 27% migration rate at 1 month. This North American multicenter trial prospectively studied a 25 mm flanged Z stent to define its palliative ability and whether the increased diameter affected placement or migration problems. METHODS: Fifty patients who had esophageal Z stents at seven university or regional referral hospitals were prospectively studied. Indications for prosthesis placement, previous therapy, patient demographics, incidence of concomitant tracheoesophageal fistula, and degree of dysphagia were defined, as were procedural and subsequent stent-related problems, survival times, the ability to occlude a tracheoesophageal fistula, and subsequent degree of dysphagia. RESULTS: Twenty-four patients had infiltrating malignancy (16 exophytic and 10 extrinsic), 9 of whom had concomitant tracheoesophageal fistulas. Ten patients (20%) had misplaced stents requiring retrieval and replacement, 12 patients (24%) had subsequent stent-related problems including exsanguination (2), aspiration (3), tumor overgrowth (3), and postplacement migration (4) (8%). There was statistically significant improvement in prestent versus poststent dysphagia and two thirds of patients had complete occlusion of their tracheoesophageal fistula. CONCLUSIONS: Redesign of the esophageal Z stent has decreased the migration rate without increasing placement or subsequent erosion problems. Its efficacy appears comparable to the currently marketed Z stent for the palliation of malignant dysphagia and occlusion of tracheoesophageal fistula.     

Cognitive performance and mood after a weekend on call in a surgical unit

BACKGROUND: Considerable interest and concern have been expressed about junior doctors' hours. This study was carried out to evaluate the emotional and cognitive effects of a weekend on call in a surgical ward. METHODS: Ten surgical house officers were assessed, in counterbalanced design, on four Monday mornings, twice after a weekend off duty and twice after a weekend on call. Cognitive functioning was assessed using the Cognitive Drug Research computerized cognitive assessment system, and emotional state was evaluated by means of the Aberdeen Mood Rating Scale. RESULTS: Following a weekend on call, significant impairment in concentration, speed and power was observed, and the doctors felt less confident, less energetic and more confused. Impaired attention, working memory, long-term memory and confusion were most closely correlated with number of hours worked on Sunday, and tiredness and confusion were related to number of hours slept. CONCLUSION: A weekend on call has significant deleterious effects on cognitive performance and mood. The findings have implications for staffing levels and the design of duty rosters.     

Female dispersion and the evolution of monogamy in the dik-dik

In facultatively monogamous mammals, females are thought to be too widely dispersed for males to defend more than one female range. We tested this hypothesis in a monogamous antelope, Kirk's dik-dik, Madoqua kirkii. Dik-dik territories were compared across three indices of quality to investigate whether males are monogamous because of constraints on the area, or resources, that they are capable of defending. Territories varied substantially in size and quality, with some containing up to five times the resources of others. Moreover, the territories of four temporarily polygynous males were not of higher quality than those of monogamous males. These results are inconsistent with the idea that dik-diks are facultatively monogamous: males can, and often do, defend enough resources and sufficient area to support two or more females. We investigated the relationship between resource dispersion and monogamy further by providing food to territories over a 3-month period. Although provisioned pairs obtained 20% of their daily requirements from the food, there was no change in the territory size of either sex. Female dispersion does not account for monogamy in the dik-dik; instead we argue that monogamy has evolved as a result of male mate guarding.Copyright 1997 The Association for the Study of Animal Behaviour