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  • Author or Editor: Dominique Votion x
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Abstract

Objective—To characterize the accuracy of an ultrafine 99m-technetium-labeled carbon dry aerosol for use in assessment of regional ventilation in calves with pulmonary dysfunction.

Animals—7 Belgian White and Blue calves.

Procedure—The ultrafine aerosol was assessed by comparing deposition (D) images with ventilation (V) images obtained by use of 81m-krypton (81mKr) gas via D-to-V ratio (D:V) image analysis in calves during spontaneous breathing (SB) and during experimentally induced pulmonary dysfunction (ePD).

Results—Mismatching index (LrTot) calculated on the D:V images revealed a good match (LrTot, 0.96 ± 0.01) between D and V distribution patterns in calves during SB. Calculation of the ultrafine aerosol penetration index relative to 81mKr (PIRel) revealed preferential distribution of the ultrafine aerosol in lung parenchyma (PIRel, 1.13 ± 0.11). In ePD, heterogeneity in the D:V distribution was observed (LrTot, 0.78 ± 0.10) as a result of ultrafine aerosol particles impaction in airways as indicated by PIRel (0.66 ± 0.16) and a proportion of pixels more radioactive in D images, compared with V images, that was located in the central part of the lung (47.5 ± 7.7% in ePD vs 32.8 ± 5.7% in SB). However, this central deposition did not prevent visual examination of the entire ventilated lung.

Conclusions and Clinical Relevance—The ultrafine aerosol appears suitable for use in examination of ventilated parts of lungs of cattle, even those with impaired pulmonary function. However, airway impaction of ultrafine aerosol particles impedes the quantification of regional ventilation in cattle with abnormal lung function. (Am J Vet Res 2001;62: 1881–1886)

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in American Journal of Veterinary Research

Abstract

Objective—To compare sensitivity of the impulse oscillometry system (IOS) with that of the conventional reference technique (CRT; ie, esophageal balloon method) for pulmonary function testing in horses.

Animals—10 horses (4 healthy; 6 with recurrent airway obstruction [heaves] in remission).

Procedure—Healthy horses (group-A horses) and heaves-affected horses (group-B horses) were housed in a controlled environment. At each step of a methacholine bronchoprovocation test, threshold concentration (TC2SD; results in a 2-fold increase in SD of a value) and sensitivity index (SI) were determined for respiratory tract system resistance (Rrs) and respiratory tract system reactance (Xrs) at 5 to 20 Hz by use of IOS and for total pulmonary resistance (RL) and dynamic lung compliance (Cdyn), by use of CRT.

Results—Bronchoconstriction resulted in an increase in Rrs at 5 Hz (R5Hz) and a decrease in Xrs at all frequencies. Most sensitive parameters were Xrs at 5 Hz (X5Hz), R5Hz, and R5Hz:R10Hz ratio; RL and the provocation concentration of methacholine resulting in a 35% decrease in dynamic compliance (PC35Cdyn) were significantly less sensitive than these IOS parameters. The TC2SD for Xrs at 5 and 10 Hz was significantly lower in group-B horses, compared with group-A horses. The lowest TC2SD was obtained for X5Hz in group-B horses and R5Hz in group-A horses.

Conclusions and Clinical Relevance—In contrast to CRT parameters, IOS parameters were significantly more sensitive for testing pulmonary function. The IOS provides a practical and noninvasive pulmonary function test that may be useful in assessing subclinical changes in horses. (Am J Vet Res 2003;64:1414–1420)

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in American Journal of Veterinary Research

Abstract

Objective—To culture equine myoblasts from muscle microbiopsy specimens, examine myoblast production of reactive oxygen species (ROS) in conditions of anoxia followed by reoxygenation, and assess the effects of horseradish peroxidase (HRP) and myeloperoxidase (MPO) on ROS production.

Animals—5 healthy horses (5 to 15 years old).

Procedures—Equine skeletal myoblast cultures were derived from 1 or 2 microbiopsy specimens obtained from a triceps brachii muscle of each horse. Cultured myoblasts were exposed to conditions of anoxia followed by reoxygenation or to conditions of normoxia (control cells). Cell production of ROS in the presence or absence of HRP or MPO was assessed by use of a gas chromatography method, after which cells were treated with a 3,3′-diaminobenzidine chromogen solution to detect peroxidase binding.

Results—Equine skeletal myoblasts were successfully cultured from microbiopsy specimens. In response to anoxia and reoxygenation, ROS production of myoblasts increased by 71%, compared with that of control cells. When experiments were performed in the presence of HRP or MPO, ROS production in myoblasts exposed to anoxia and reoxygenation was increased by 228% and 183%, respectively, compared with findings for control cells. Chromogen reaction revealed a close adherence of peroxidases to cells, even after several washes.

Conclusions and Clinical Relevance—Results indicated that equine skeletal myoblast cultures can be generated from muscle microbiopsy specimens. Anoxia-reoxygenationtreated myoblasts produced ROS, and production was enhanced in the presence of peroxidases. This experimental model could be used to study the damaging effect of exercise on muscles in athletic horses.

Full access
in American Journal of Veterinary Research