Objective—To determine concentrations of nitric
oxide (NO) in plasma and bronchoalveolar lavage fluid
(BALF) and localize nitric oxide synthesis in the lungs
of horses with summer pasture-associated obstructive
pulmonary disease (SPAOPD).
Animals—7 adult horses with SPAOPD and 6 clinically
normal adult horses.
Procedure—Severity of SPAOPD was determined by
use of clinical scores, change in intrapleural pressure
(ΔPpl) during tidal breathing, cytologic analysis of
BALF, and histologic evaluation of lung specimens
obtained during necropsy. Nitric oxide concentrations
in plasma, BALF, and epithelial lining fluid (ELF) were
determined by use of a chemiluminescent method.
Inducible nitric oxide synthase (iNOS) and nitrotyrosine
(NT) were localized in formalin-fixed lung specimens
by use of immunohistochemical staining, and
nicotinamide adenine dinucleotide phosphate
diaphorase (NADPHd) activity was localized in cryopreserved
specimens by use of histochemical staining.
Results—Plasma concentration of NO in affected
horses was slightly but not significantly greater than
concentration in nonaffected horses. Nitric oxide concentrations
in BALF or ELF did not differ between
groups. Immunoreactivity of iNOS in bronchial epithelial
cells of 3 of 5 lung lobes was greater in horses
with SPAOPD, compared with nonaffected horses.
However, staining for NT and NADPHd activity did not
differ between groups.
Conclusions and Clinical Relevance—Expression of
iNOS was greater in bronchial epithelial cells of horses
with SPAOPD, compared with nonaffected horses,
suggesting that NO may play a role in amplifying the
inflammatory process in the airways of horses with
this disease. (Am J Vet Res 2001;62:1381–1386)
Objective—To determine whether hyperbaric oxygen
treatment (HBOT) would affect incorporation of an
autogenous cancellous bone graft in diaphyseal ulnar
defects in cats.
Animals—12 mature cats.
Procedure—Bilateral nonunion diaphyseal ulnar
defects were created in each cat. An autogenous
cancellous bone graft was implanted in 1 ulnar
defect in each cat, with the contralateral ulnar
defect serving as a nongrafted specimen. Six cats
were treated by use of hyperbaric oxygen at 2
atmospheres absolute for 90 minutes once daily for
14 days, and 6 cats were not treated (control
group). Bone labeling was performed, using fluorochrome
markers. Cats were euthanatized 5
weeks after implanting, and barium sulfate was
infused to evaluate vascularization of grafts. Ulnas
were evaluated by use of radiography, microangiography,
histologic examination, and histomorphometric
Results—Radiographic scores did not differ
between treatment groups. Microangiographic
appearance of grafted defects was similar between
groups, with all having adequate vascularization.
Differences were not observed between treated
and nontreated groups in the overall histologic
appearance of decalcified samples of tissue in grafted
defects. Mean distance between fluorescent
labels was significantly greater in cats given HBOT
than in nontreated cats. Median percentage of bone
formation in grafted defects was significantly
greater in cats given HBOT.
Conclusions—Hyperbaric oxygen treatment
increased the distance between fluorescent labels
and percentage of bone formation when incorporating
autogenous cancellous bone grafts in induced
nonunion diaphyseal ulnar defects in cats, but HBOT
did not affect revascularization, radiographic appearance,
or qualitative histologic appearance of the
grafts. (Am J Vet Res 2000;61:691–698)