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  • Author or Editor: Susan R. Lindborg x
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Summary

Bronchoalveolar lavage (bal) was performed on 16 horses to determine whether it caused local or diffuse inflammation in the lungs. In 7 horses, bal was performed in both lungs twice, 48 hours apart. Although total cell counts of the bal samples did not change significantly, there were increased numbers and percentage of neutrophils in the second lavage fluid samples. In 5 horses, bal was performed in 1 lung and repeated 48 hours later in the same lung and in the corresponding airway in the contralateral lung. The absolute cell count and percentage of neutrophils were significantly (P = < 0.05) increased in the second sample from the lung that was lavaged twice. In 4 horses, bal was performed in 1 lung and 48 hours later, repeated in an adjacent airway to the first bal site, and in the corresponding airway in the contralateral lung. Significant differences were not detected the total or differential cell counts of the bal fluid recovered at any time, except for an increase in neutrophil percentage in the second sample in the contralateral lung. The increased neutrophil percentage values were within the range of normal for healthy horses.

Results of the study suggested that, in horses, bal induces a localized pulmonary neutrophil influx that persists at least 48 hours and is characterized by a relative and absolute increase in the number of neutrophils in the lavage fluids.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine sensitivity of equine skeletal muscle to tetrodotoxin and compare that with sensitivity of murine and human skeletal muscles.

Sample Population—Semimembranosus, vastus lateralis, triceps brachii, and masseter muscle specimens from 22 euthanatized horses, vastus lateralis muscle biopsy specimens from 25 clinically normal humans, and diaphragmatic muscle specimens from 6 mice.

Procedure—Electrically elicited twitch responses were measured in muscle specimens incubated in medium alone and with tetrodotoxin (100 nM, 400 nM, 1.6 µM for equine specimens and 100 nM, 200 nM, 400 nM, 800 nM, 1.6 µM for murine and human specimens). Percentages of tetrodotoxin-sensitive and -resistant sodium channels were determined and compared among muscles and species.

Results—2 sodium channels with different sensitivities to tetrodotoxin were identified in equine muscle. One was blocked with 100 nM tetrodotoxin and the other was unaffected by tetrodotoxin at concentrations up to 1.6 µM. The only difference detected among the 4 equine muscles was that masseter muscle specimens had a higher percentage of tetrodotoxin- sensitive channels than triceps brachii muscle specimens. Tetrodotoxin-resistant sodium channels constituted 31 to 66% of the equine muscle twitch response, which was greater than that determined for normal human and murine muscle (< 5%).

Conclusion and Clinical Relevance—Equine skeletal muscle contains a high percentage of tetrodotoxin-resistant sodium channels. The 4 equine muscles evaluated were more similar to each other than to murine and human muscles. Shifts in expression of sodium channel subtypes may play a role in the manifestation of certain myopathies. (Am J Vet Res 2000;61:133–138)

Full access
in American Journal of Veterinary Research

SUMMARY

The endobronchial anatomy of 12 lung specimens from horses and 12 healthy, standing, sedated horses was evaluated, using a 200-cm-long, 9.5-mm-diameter videoendoscope. On the basis of these findings, the nomenclature system of Amis and McKiernan was modified for identification of airways of horses during bronchoscopy. Lobar bronchi are identified on the basis of the side of the bronchial tree on which they were found and the order in which they originated from the primary bronchus. Thus, RB1, RB2, and RB3 referred to right cranial lobar bronchus, respectively. On the left side, the designation of LB1 and LB2 refer to the left cranial lobar bronchus and the left caudal lobar bronchus, respectively. Segmental bronchi are identified by consecutive numbers in the order of origination from the lobar bronchus. The direction of the segmental bronchus was denoted by the capital letter D (dorsal), V (ventral), L (lateral), M (medial), R (rostral), and C (caudal). Subsegmental bronchi were identified in the order of origination from the segmental bronchi, using lower case letters (eg, RB2, 1V, a or RB2, 1V, aV). For subsequent branching of the subsegmental bronchi, the branches were numbered consecutively by their order of origination (eg, RB2, 1V, aV, 1D).

Free access
in American Journal of Veterinary Research