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Background: Bovine respiratory disease (BRD) is an important problem in cattle production that is responsible for economic losses in dairy herds. Mycoplasma spp. are described as an important etiological agent of BRD. Hypothesis:To evaluate the occurrence of the most important mycoplasmas in the lower respiratory tract of healthy and BRD cattle in relationship to clinical signs of BRD. Animals: Sixty young dairy cattle were classified as healthy (n = 32) or cattle showing clinical signs of BRD (n = 28). Methods: Tracheal lavage samples were collected and added to tubes containing Hayflick media. Mycoplasma spp. were identified by the presence of “fried egg” like colonies, biochemical tests and polymerase chain reaction (PCR). Occurrence of Mollicutes, M. bovis, M. mycoides subsp. mycoides SC and M. dispar was evaluated. The association between clinical signs of BRD and the presence of Mycoplasma spp. also was evaluated. Results: Colonies were obtained from a 1-year-old BRD calf only. However, species identification was not possible. Mollicutes (P = .035) and M. dispar (P = .036) were more common in BRD cattle. The relationship between Mollicutes and crackle (P = .057) was not significant. M. dispar was associated to tachypnea (P = .045) and mixed dyspnea (P = .003). Relationships to heart rate (P = .062) and crackle (P = .062) were not significant. Conclusions and clinical importance: The results confirmed the importance of mycoplasma as an etiologic agent of BRD and suggested M. dispar as part of the respiratory microbiota and its possible role in the development of BRD. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to define a method to evaluate the total dose delivered to the rectum during the whole treatment course in six patients undergoing irradiation for prostate cancer using an offline definition of organ motion with images from a cone beam CT (CBCT) scanner available on a commercial linear accelerator. Methods: Patient set-up was verified using a volumetric three-dimensional CBCT scanner; 9-14 CBCT scans were obtained for each patient. Images were transferred to a commercial treatment planning system for offline organ motion analysis. The shape of the rectums were used to obtain a mean dose-volume histogram (,DVH.), which was the average of the DVHs of the rectums as they appeared in each verification CBCT. A geometric model of an average rectum (AR) was produced using the rectal contours delineated on the CBCT scans (DVHAR). To check whether the first week of treatment was representative of the whole treatment course, we evaluated the DVHs related to only the first five CBCT scans (,DVH5. and DVHAR5). Finally, the influence of a dietary protocol on the goodness of our results was considered. Results: In all six patients the original rectal DVH for the planning CT scan showed higher values than all DVHs. Conclusion: Although the application of the model to a larger set of patients is necessary to confirm this trend, reconstruction of a representative volume of the rectum throughout the entire treatment course seems feasible. [ABSTRACT FROM AUTHOR]