The Use of Preoperative Transcranial Doppler Variables to Predict Which Patients do Not Need a Shunt During Carotid Endarterectomy

AbstractObjectives: to analyse whether preoperative transcranial Doppler (TCD) variables can predict intraoperative shunt requirement. Design and methods: the blood-flow velocity (BFV) in the major basal cerebral arteries was measured preoperatively with TCD, in 178 patients scheduled for CEA. Carotid artery compression and CO2 reactivity tests were also performed. Intraoperative electroencephalography was used to decide whether a shunt was needed. Differences in the probability of shunt requirement between the categories of variables were assessed with crosstabs statistics. Results: preoperative TCD criteria clearly identified a subgroup of 59 patients (33%) who did not require a shunt. In general, these patients appeared to have adequate collateral flow through the anterior communicating artery. In contrast, prediction of the need for a shunt was less reliable. TCD variables could predict the need for a shunt with a probability of only 60%.Conclusions: preoperative TCD can be used to identify patients who do not require a shunt during carotid endarterectomy

Quality of ultrasound biometry obtained by local health workers in a refugee camp on the Thai-Burmese border.

Objective: In a refugee camp on the Thai–Burmese border, accurate dating of pregnancy relies on ultrasound measurements obtained by locally trained health workers. The aim of this study was to substantiate the accuracy of fetal biometry measurements performed by locally trained health workers by comparing derived reference equations with those published for Asian and European hospitals. Methods: This prospective observational study included 1090 women who had a dating crown–rump length (CRL) scan and one study-appointed ultrasound biometry scan between 16 and 40 weeks of gestation. The average of two measurements of each of biparietal diameter, head circumference, abdominal circumference and femur length was used in a polynomial regression model for the mean and SD against gestational age (GA). The biometry equations obtained were compared with published equations of professional sonographers from Asian and European hospitals by evaluation of the SD and Z-scores of differences between models. Results: Reference equations of biometric parameters were found to fit cubic polynomial models. The observed SD values, for any given GA, of fetal biometric measurements obtained by locally trained health workers were lower than those previously reported by centers with professional sonographers. For nearly the entire GA range considered, the mean values of the Asian and European equations for all four biometric measurements were within the 90% expected range (mean ± 1.645 SD) of our equations. Conclusion: Locally trained health workers in a refugee camp on the Thai–Burmese border can obtain measurements that are associated with low SD values and within the normal limits of published Asian and European equations. The fact that the SD values were lower than in other studies may be explained by the use of the average of two measurements, CRL dating or motivation of the locally trained sonographer

Basal metabolic rate in relation to body composition and daily energy expenditure in the field vole, Microtus agrestis

Basal metabolic rate in the field vole (Microtus agrestis) was studied in relation to body composition and daily energy expenditure in the field Daily energy expenditure was measured by means of doubly labelled water ((D2O)-O-18). In the same individuals, basal metabolic rate was subsequently derived from O-2 consumption in an open-circuit system in the laboratory. Body composition was obtained by dissecting the animals and determining fresh, dry, and lean dry mass of different organs. Daily energy expenditure for free-living field voles ranged from 1.8 to 4.5 times basal metabolic race, with an average of 2.9 times basal metabolic rate. Variation in both daily energy expenditure and basal metabolic rate was best explained by body mass. Gender or reproductive activity did not have significant additive effects. Daily energy expenditure and basal metabolic rate showed significant positive relationships to body mass with similar mass exponents of 0.493 and 0.526, respectively. Overall, there was a significant correlation between daily energy expenditure and basal metabolic rate, but the mass-independent residuals (deviations from the allometrically predicted values) did not correlate. Carcass analysis revealed that a number of organs were slightly better predictors for daily energy expenditure and basal metabolic rate than was fresh body mass. Mass-independent residuals of lean dry heart mass and basal metabolic rate were positively correlated, which is in agreement with the idea that basal metabolic rate reflects the size of metabolically active organs. The study does not provide support for an intraindividual association of basal metabolic rate with daily energy expenditure in the field

Energy expenditure during egg laying is equal for early and late breeding free-living female great tits

In many bird populations, variation in the timing of reproduction exists but it is not obvious how this variation is maintained as timing has substantial fitness consequences. Daily energy expenditure (DEE) during the egg laying period increases with decreasing temperatures and thus perhaps only females that can produce eggs at low energetic cost will lay early in the season, at low temperatures. We tested whether late laying females have a higher daily energy expenditure during egg laying than early laying females in 43 great tits (Parus major), by comparing on the same day the DEE of early females late in their laying sequence with DEE of late females early in their egg laying sequence. We also validated the assumption that there are no within female differences in DEE within the egg laying sequence. We found a negative effect of temperature and a positive effect of female body mass on DEE but no evidence for differences in DEE between early and late laying females. However, costs incurred during egg laying may have carry-over effects later in the breeding cycle and if such carry-over effects differ for early and late laying females this could contribute to the maintenance of phenotypic variation in laying dates

Does Work Affect Personality? A Study in Horses

It has been repeatedly hypothesized that job characteristics are related to changes in personality in humans, but often personality models still omit effects of life experience. Demonstrating reciprocal relationships between personality and work remains a challenge though, as in humans, many other influential factors may interfere. This study investigates this relationship by comparing the emotional reactivity of horses that differed only by their type of work. Horses are remarkable animal models to investigate this question as they share with humans working activities and their potential difficulties, such as “interpersonal” conflicts or “suppressed emotions”. An earlier study showed that different types of work could be associated with different chronic behavioural disorders. Here, we hypothesised that type of work would affect horses' personality. Therefore over one hundred adult horses, differing only by their work characteristics were presented standardised behavioural tests. Subjects lived under the same conditions (same housing, same food), were of the same sex (geldings), and mostly one of two breeds, and had not been genetically selected for their current type of work. This is to our knowledge the first time that a direct relationship between type of work and personality traits has been investigated. Our results show that horses from different types of work differ not as much in their overall emotional levels as in the ways they express emotions (i.e. behavioural profile). Extremes were dressage horses, which presented the highest excitation components, and voltige horses, which were the quietest. The horses' type of work was decided by the stall managers, mostly on their jumping abilities, but unconscious choice based on individual behavioural characteristics cannot be totally excluded. Further research would require manipulating type of work. Our results nevertheless agree with reports on humans and suggest that more attention should be given to work characteristics when evaluating personalities