Enhancement of sound motion detection in acallosal individuals

It has been proposed that the corpus callosum may play an important role in spectral cue processing that allows vertical auditory movement perception. The purpose of the present study was to assess the contribution of the corpus callosum to this type of auditory processing. Noise bursts were presented to 10 control and two callosal agenesis individuals from different positions located within midsagittal and coronal planes. Although acallosal participants were comparable with controls in their ability to correctly identify the trajectory direction or its length, they showed greater capability in detecting motion per se when the task was difficult. These results suggest that in the absence of the corpus callosum, compensatory reorganization of the brain allowed for superior auditory spectral cue processing.     

Auditory scene analysis following unilateral inferior colliculus infarct

Event-related potentials in the form of mismatch negativity were recorded to investigate auditory scene analysis capabilities in a person with a very circumscribed haemorrhagic lesion at the level of the right inferior colliculus. The results provide the first objective evidence that processing at the level of the inferior colliculus plays an important role in human auditory frequency discrimination. Moreover, the electrophysiological data suggest that following this unilateral lesion, the auditory pathways fail to reorganize efficiently.     

Ureteral obstruction and Crohn's disease

Noncalculous ureteral obstructions in Crohn's disease are often asymptomatic and unidentified. Occurring in about 3% of patients, they occur on the right side in more than 70% of cases, because of frequently associated ileocecal disease. If they are associated with inflammation or fibrosis of retroperitoneal periureteral fat nephrectomy may become necessary. Conservative treatment should be considered first, with urine drainage (ureteral stent, or percutaneous nephrostomy), diet, and corticotherapy. However bowel resection is often necessary during follow up. If this fails to cure the ureteral obstruction, ureterolysis should be performed. We report the case of a 32 year old woman with noncalculous ureteral obstruction revealing Crohn's disease.     

Developing an interstitial ultrasound applicator for thermal ablation in liver: results of animal experiments

BACKGROUND: In this project, an interstitial ultrasound applicator was developed for the treatment of primary and secondary cancers of the liver. Experiments on animals were used to check the destructive capabilities of this probe within the hepatic parenchyma of the pig in vivo, with a study of the physical parameters of the ultrasound treatment. In parallel, the possibility of visualizing the lesions induced by means of ultrasound imaging was also studied. MATERIALS AND METHODS: Thirteen pigs were used in this project, which had received the prior approval of the ethics committee of Lyon Veterinary School. Ultrasound lesions were performed by varying the physical parameters of the treatment (acoustic intensity and shot time) with the aim of obtaining larger and larger areas of destruction. An operative device was developed to ensure precision in treatments. Two types of lesions were performed: elementary lesions corresponding to single shots at 40 degrees to 50 degrees rotation intervals, and cylindrical lesions obtained by a continuous rotary deployment of the probe. The effect of hepatic pedicle clamping on the size of ultrasound lesions was studied. The aspect and dimension of the lesions were analyzed by means of operative ultrasound imaging and macroscopic examination. Histological analysis showed the impact of the treatment on the hepatic parenchyma. RESULTS: This work made it possible to study the elementary ultrasound lesions produced by our probe. Seventy elementary ultrasound lesions were analyzed. Treatments could be performed on all pigs without any difficulty. There were no operative incidents. The ultrasound-induced elementary lesions showed complete necrosis, with lesion length of up to 37 mm obtained without resort to pedicle clamping; this must be considered as a radius of the final lesion obtained over a complete rotary deployment (360 degrees ), then a diameter of 7 cm of thermal ablation can theoretically be obtained. The effect of pedicle clamping was studied and showed improvement of the lesion length. Results of continuous rotary deployment of the probe were encouraging. Operative ultrasound imaging proved to be a simple tool for directing and positioning the applicator in the target zone on the one hand and which, on the other hand, enabled accurate, real-time visualization of the ultrasound lesions. On histological analysis, the ultrasound-induced necrosis was complete and well defined. CONCLUSION: This work shows that it is feasible to treat cancers of the liver using interstitial ultrasound probe. Thermal damage obtained on the hepatic parenchyma of pigs in vivo is complete and can be monitored using simple diagnostic ultrasound. The ultrasound parameters can be adapted to obtain destruction of variable size.     

Effects of caffeine on daytime recovery sleep: A double challenge to the sleep–wake cycle in aging

Background and objectiveCaffeine is the most widely used stimulant to counteract the effects of sleepiness, but it also produces important detrimental effects on subsequent sleep, especially when sleep is initiated at a time when the biological clock sends a strong waking signal such as during daytime. This study compares the effects of caffeine on daytime recovery sleep in young (20–30 y.) and middle-aged subjects (45–60 y.).MethodsSubjects participated in both caffeine (200 mg) and placebo conditions (double-blind cross-over design), spaced one month apart. For each condition, subjects initially came to the laboratory for a nocturnal sleep episode. Daytime recovery sleep started in the morning after 25 h of wakefulness. Subjects were administered either one caffeine (100 mg) or placebo capsule three hours before daytime recovery sleep and the remaining dose one hour before daytime recovery sleep.ResultsMiddle-aged subjects showed greater decrements of sleep duration and sleep efficiency than young subjects during daytime recovery under placebo compared to nocturnal sleep. Caffeine decreased sleep efficiency, sleep duration, slow-wave sleep (SWS) and REM sleep during daytime recovery sleep similarly in both age groups. Caffeine also reduced N-REM sleep EEG synchronization during daytime recovery sleep (reduced delta, theta, and alpha power, and greater beta power).ConclusionsThe combined influence of age and caffeine made the sleep of middle-aged subjects particularly vulnerable to the circadian waking signal. We propose that lower brain synchronization due to age and caffeine produces greater difficulty in overriding the circadian waking signal during daytime sleep and leads to fragmented sleep. These results have implications for the high proportion of the population using caffeine to cope with night work and jet lag, particularly the middle-aged.     

Sleep following sport-related concussions

ObjectivesSleep and vigilance disorders are among the most commonly reported symptoms following a concussion. The aim of the study was thus to investigate the effects of sport-related concussions on subjective and objective sleep quality.MethodsTen concussed athletes and 11 non-concussed athletes were included. Concussed athletes had a history of 4.6 ± 2.1 concussions with at least one concussion during the last year. They were recorded for two consecutive nights in the laboratory and during a 10-min period of wakefulness. They completed questionnaires related to sleep quality and symptoms as well as neuropsychological tests and the CogSport computer battery.ResultsConcussed athletes reported more symptoms and worse sleep quality than control athletes, but no between-group differences were found on polysomnographic variables or on REM and NREM sleep quantitative EEG variables. However, concussed athletes showed significantly more delta activity and less alpha activity during wakefulness than did control athletes.ConclusionIn spite of the subjective complaints in sleep quality of concussed athletes, no change was observed in objective sleep characteristics. However, concussions were associated with an increase in delta and a reduction in alpha power in the waking EEG. Sport-related concussions are thus associated with wakefulness problems rather than sleep disturbances.     

Comparative assessing for radiological, chemical, and physical exposures at the French uranium conversion plant: Is uranium the only stressor?

This study presents the pattern of exposure to uranium and other occupational pollutants known to be potentially carcinogenic, mutagenic or toxic and used at the main uranium conversion plant in France. For different uranium compounds specified according to their solubility and purity, and 16 other categories of pollutants: chemicals, fibres, vapours, dust, and heat a time- and plant-specific job exposure matrix (JEM) was created covering the period 1960-2006. For 73 jobs and for each pollutant the amount and frequency of exposure were assessed on a four-level scale by different time periods. The JEM shows 73% sensitivity and 83% specificity. Although exposure assessment was semi-quantitative, the JEM allows computing of individual cumulative exposure score for each pollutant across time. Despite the predominant natural uranium compounds exposure, the amount of exposure to other pollutants such as TCE and other chlorinated products, asbestos, and fibres, is important at the plant. Numerous correlations detected between uranium compounds exposure and exposure to chemicals warrants improving biological monitoring of exposed workers and accounting for associated exposures in epidemiological studies. Results of this study will be used for further investigation of association between exposure and mortality among uranium conversion workers cohort.     

Measurement and management of work climate: Cross-validation of the CRISO Psychological Climate Questionnaire

This paper presents research results that offer answers to the “why,” “what” and “how” of work climate measurement. It also submits to the scientific community a confirmatory cross-validation procedure applied to a new measurement tool, consistent with the works of Jones and James's (1979) and of Parker et al. (2003) on psychological climate. The results depict a good model fit for both the English and French versions of the questionnaire. This new instrument offers a comprehensive and manageable approach for the development of a healthy workplace.