Abstract-The potential of physical exercise to decrease body weight, alleviate depression, combat aging and enhance cognition has been well-supported by research studies. However, exercise regimens vary widely across experiments, raising the question of whether there is an optimal form, intensity and duration of exertion that would produce maximal benefits. In particular, a comparison of forced and voluntary exercise is needed, since the results of several prior studies suggest that they may differentially affect brain and behavior. In the present study, we employed a novel 8-week exercise paradigm that standardized the distance, pattern, equipment and housing condition of forced and voluntary exercisers. Exercising rats were then compared with sedentary controls on measures previously shown to be influenced by physical activity. Our results indicate that although the distance covered by both exercise groups was the same, voluntary exercisers ran at higher speed and for less total time than forced exercisers. Although evidence of the neural and behavioral benefits of exercise is accumulating, the optimal type, duration and intensity of long-term physical activity have not been established. Laboratory animal models of chronic exercise are highly variable, with many studies utilizing ad libitum access to voluntary exercise wheels, while others employ comparably short bouts of forced exercise on a treadmill. Not surprisingly, studies of the same outcome measure produce different results, depending on whether a voluntary or forced exercise paradigm is used (for a recent review of these disparities, see Ang and Gomez-Pinilla, 2007). In addition, it is becoming increasingly recognized that no single exercise paradigm is likely to fulfill all therapeutic needs (Ang and Gomez-Pinilla, 2007;Cotman et al., 2007). Thus, it is imperative to study the neural and behavioral effects of different forms of chronic exercise while holding their parameters constant.Human studies have attempted to pinpoint the optimal intensity level at which acute exercise maximally benefits cognition (Winter et al., 2007;McMorris et al., 2008, see Brisswalter et al., 2002 for a useful review), event-related brain potentials (ERP's) (Kamijo et al., 2004b(Kamijo et al., , 2007 and arousal level (Kamijo et al., 2004a). The most beneficial intensity, duration and type of long-term physical activity have not been well-studied in laboratory animals, however. The type of exercise may be particularly important, since several lines of evidence suggest that forced exercise and voluntary exercise exert different effects on the brain and behavior. For example, forced and voluntary exercise differentially affect monoamine neurotransmitters (Dishman, 1997), hippocampal parvalbumin expression (Arida et al., 2004), hippocampal brain-derived neurotrophic factor and synapsin-1 expression (Ploughman et al., 2005), longevity and body composition (Narath et al., 2001), taste aversion learning (Masaki and Nakajima, 2006) and open-field behavior (Burghardt et al., 2004...

Between December 5, 1989, and September 25, 1990, Mycobacterium chelonae was isolated from endoscopic or bronchial washings in 14 patients on a single clinical service. A phenotypically unique strain of M. chelonae subspecies abscessus that was highly resistant to cefoxitin (MIC greater than 256 micrograms/ml) and different from 13 control isolates of M. chelonae recovered elsewhere in the hospital was identified in all these patients and the rinse water from the bronchoscope disinfecting machine. None of the outbreak patients had evidence of invasive M. chelonae disease. Aggressive infection control measures on the disinfecting machine, including use of sterile water in the wash and rinse cycles, increasing the 2% alkaline glutaraldehyde exposure time, frequent replacement of the glutaraldehyde, and disinfection of the machine, failed to eradicate the M. chelonae, presumably because of the presence of a biofilm inside the machine. Rinsing the scopes with 70% alcohol after automated disinfection eliminated the outbreak strain. This study demonstrates that automated bronchoscope disinfecting machines may become heavily contaminated with mycobacteria that resist usual disinfection, resulting in a source of bronchoscope contamination.

In the hospitals studied, only a small number of rooms were designated for respiratory isolation, and the performance of these was not tested routinely. High-risk areas including intensive care units and emergency rooms were not equipped to provide respiratory isolation. The direction of airflow in respiratory isolation rooms was not always correct and should be evaluated frequently.

We describe a prolonged nosocomial outbreak of Salmonella senftenberg, an uncommon human pathogen. We detected 22 cases of infection due to S. senftenberg that occurred from March 1993 through November 1994 and involved 18 patients and four healthy employees. All infected persons had consumed food prepared by the hospital kitchen. The estimated attack rate for the period of the outbreak was 0.19-0.23 cases per 100,000 meals served. Infection control interventions included observation of food preparation, disinfection of kitchen devices, and education of food handlers. The consumption of lettuce (11 of 15 patients who could recount extended dietary histories vs. 4 of 20 controls; P = .005), cauliflower (5 of 15 vs. 0/20; P = .02), cottage cheese (4 of 15 vs. 0/20; P = .03), and deli turkey (8 of 15 vs. 0/20; P < .001) was associated with S. senftenberg infection. The isolates had identical antibiograms and pulsed-field gel electrophoretic patterns. Cultures of stool samples from food handlers as well as food items, kitchen devices, and kitchen surroundings were negative for S. senftenberg. Interruption of the outbreak occurred coincidentally with the institution of infection control measures. This prolonged outbreak of salmonellosis was probably related to contamination in the kitchen from turkey, with cross-contamination via equipment.