Short communication: Characterizing ovine serum stress biomarkers during endotoxemia

Breeding stress-resilient livestock is a potential strategy to help mitigate the negative effect of environmental and pathogenic stressors. The hypothalamic-pituitary-adrenal axis and immune system are activated during stress events and release mediators into the circulation that help restore physiological homeostasis. The purpose of this study was to assess a comprehensive set of circulatory mediators released in response to an acute immune stress challenge to identify candidate biomarkers that can be used for the selection of stress-resilient animals. Fifteen female lambs were stress challenged with an intravenous bolus of lipopolysaccharide (LPS; 400 ng/kg), and blood was collected from the jugular vein at 0, 2, 4, and 6 h after LPS challenge to identify and monitor candidate stress biomarkers; temperature was also recorded over time. Biomarker responses were evaluated with a repeated-measures model to compare time points with baseline values. As expected, all sheep had a monophasic febrile response to LPS challenge, and cortisol increased and returned to baseline by 6 h. The cytokines tumor necrosis factor-α, IL-6, IFN-γ (proinflammatory), and IL-10 (anti-inflammatory) increased, but only tumor necrosis factor-α returned to baseline during the monitoring period. The cytokines IL-1α, IL-1β, IL-17α (proinflammatory), and IL-4 (anti-inflammatory) did not respond to LPS challenge. All chemokines (CCL2, CCL3, CCL4, CXCL10, and IL-8) responded to LPS challenge; however, only CCL2, CCL3, CCL4, and CXCL10 increased over time, and only CCL3, CCL4, and CXCL10 returned to baseline during the monitoring period. MicroRNA (miR-145, miR-233, and miR-1246) also increased and remained elevated during the study. In summary, the LPS challenge induced a strong stress response in Rideau-Dorset sheep that could be monitored with a distinct profile of circulatory biomarkers.

Open, randomized therapeutic trial of six antimicrobial regimens in the treatment of human brucellosis

This report describes the results of six antimicrobial regimens used for the treatment of brucellosis in an open, randomized study performed over two periods (1980-1983 and 1984-1987). In the first period, rifampicin and doxycycline were used for 4 weeks, trimethoprim-sulfamethoxazole for 6 months, and doxycycline for 6 weeks. During the second period, we used streptomycin for 2 or 3 weeks together with doxycycline for 6 weeks and rifampicin with doxycycline for 6 weeks. Comparison of the results showed the following: (1) no statistically significant findings were revealed when the different regimens were compared and (2) the regimens containing streptomycin yielded statistically more favorable results than those consisting of rifampicin and monotherapy when the patients treated with rifampicin were compared with those taking streptomycin and those receiving single-agent therapy. No significant differences were observed between monotherapeutic regimens and those including rifampicin.