Objective: To identify cardiac mechanisms that contribute to adaptation to high altitudes in Tibetan antelope (Pantholops hodgsonii). Animals: 9 male Tibetan antelope and 10 male Tibetan sheep (Ovis aries). Procedures: Tibetan antelope and Tibetan sheep inhabiting a region with an altitude of 4,300 m were captured, and several cardiac variables were measured. Expression of genes for atrial natriuretic peptide, brain natriuretic peptide, and calcium-calmodulin–dependent protein kinase II δ was measured via real-time PCR assay. Results: Ratios of heart weight to body weight for Tibetan antelope were significantly greater than those of Tibetan sheep, but ratios of right-left ventricular weights were similar. Mean ± SD baseline heart rate (26.33 ± 6.15 beats/min) and systolic arterial blood pressure (97.75 ± 9.56 mm Hg) of antelope were significantly lower than those of sheep (34.20 ± 6.57 beats/min and 130.06 ± 17.79 mm Hg, respectively). The maximum rate of rise in ventricular pressure in antelope was similar to that in Tibetan sheep, but after exposure to air providing a fraction of inspired oxygen of 14.6% or 12.5% (ie, hypoxic conditions), the maximum rate of rise in ventricular pressure of the antelope increased significantly to 145.1% or 148.1%, respectively, whereas that of the sheep decreased to 68.4% or 70.5%, respectively. Gene expression of calcium-calmodulin–dependent protein kinase II δ and atrial natriuretic peptide, but not brain natriuretic peptide, in the left ventricle of the heart was significantly higher in antelope than in sheep. Conclusions and Clinical Relevance: Hearts of the Tibetan antelope in this study were well adapted to high-altitude hypoxia as shown by higher heart weight ratios, cardiac contractility in hypoxic conditions, and expression of key genes regulating cardiac contractility and cardiac hypertrophy, compared with values for Tibetan sheep.

Objective—To determine antimicrobial effects of caprylic acid and its derivatives, monocaprylin and sodium caprylate, on Dermatophilus congolensis and to determine effects of caprylic acid on the ultrastructure of D congolensis by use of transmission electron microscopy (TEM). Sample—3 strains of D congolensis (33411, 33413, and 14639). Procedures—Strains of D congolensis were incubated separately under anaerobic conditions at 37°C for up to 48 hours in brain heart infusion (BHI) broth that was supplemented with various concentrations of caprylic acid (7.5, 12.5, 15, 17.5, or 20mM), monocaprylin (2.5, 5, 7.5, or 10mM), or sodium caprylate (15, 50, 60, 70, 100, or 120mM) or contained no antimicrobial treatment. After incubation, bacterial counts were determined by means of plating in triplicate on BHI-agar plates. Caprylic acid-treated or untreated D congolensis samples were embedded in epoxide resin for TEM; cross sections were examined for structural damage. Results—Minimum inhibitory concentrations of caprylic acid, monocaprylin, and sodium caprylate against D congolensis were 7.5, 2.5, and 15mM, respectively. Minimum bactericidal concentrations of caprylic acid, monocaprylin, and sodium caprylate against D congolensis were 15, 5, and 70mM, respectively. Examination via TEM revealed that a 15-mM concentration of caprylic acid disintegrated the plasma membrane of D congolensis. Conclusions and Clinical Relevance—Results indicated that caprylic acid, monocaprylin, and sodium caprylate could potentially be used to treat D congolensis infections. However, in vivo studies should be undertaken to determine whether these compounds can be considered as treatment options.