Objective—To determine effects of short-chain fatty
acids (SCFA) on canine colonic smooth muscle.
Sample Population—Colonic tissue obtained from
14 healthy dogs.
Procedure—Short-chain fatty acid (SCFA; acetate,
propionate, and butyrate; 1 to 100 mmol/L)-induced
contractions were compared with responses
obtained with acetylmethylcholine (AMCh; 10-4 mol/L).
Roles of enteric neurons, cholinergic receptors, calcium
stores in the sarcoplasmic reticulum, and extracellular
calcium in the SCFA-induced responses were
investigated by incubating muscle strips with
tetrodotoxin (1 µmol/L), atropine (1 µmol/L), ryanodine
(10 µmol/L), nifedipine (1 µmol/L), ethylene glycol-bis (β-aminoethylether)-N,N,N',N'-tetra-acetate
(EGTA; 0.1 mmol/L), or an extracellular calciumdepleted
(zero extracellular calcium) solution prior to
the addition of propionate or butyrate.
Results—Incubation with SCFA elicited isometric
stress responses (0.25 to 2.15 × 104 N/m2) in colonic
longitudinal smooth muscle. Maximal responses to
butyrate and propionate (50 mmol/L) were 37 and
23%, respectively, of the maximal AMCh response.
Acetate was least effective in stimulating contractile
responses. Tetrodotoxin and atropine did not affect
SCFA-induced contractions. Nifedipine and zero extracellular
calcium solution abolished responses to
butyrate and propionate, whereas EGTA attenuated (>
60%) but did not abolish those responses. Ryanodine
did not affect SCFA-induced contractile responses.
The SCFA did not affect colonic circular smooth muscle.
Conclusions and Clinical Relevance—The SCFA
stimulate longitudinal but not circular colonic smooth
muscle contractions via a direct effect on smooth
muscle. The mechanism of the SCFA effect appears
to involve the influx of extracellular calcium. These
findings may account for some of the effects of
canine colonisc motility. (Am J Vet Res 2002;63:295–300 )
To describe complications and outcomes of dogs undergoing unilateral thyroidectomy for the treatment of thyroid tumors.
156 dogs undergoing unilateral thyroidectomy for a naturally occurring thyroid tumor.
Dogs that underwent a unilateral thyroidectomy in 2003 through 2015 were included in a multi-institutional retrospective study. For each dog, information gathered through evaluation of electronic and paper records included perioperative complications, short-term outcome (survival to discharge from the hospital vs nonsurvival), and long-term outcome (survival time).
In the perioperative period, complications occurred in 31 of the 156 (19.9%) dogs; hemorrhage was the most common intraoperative complication (12 [7.7%] dogs). Five of 156 (3.2%) dogs received a blood transfusion; these 5 dogs were among the 12 dogs that had hemorrhage listed as an intraoperative complication. Immediately after surgery, the most common complication was aspiration pneumonia (5 [3.2%] dogs). One hundred fifty-three of 156 (98.1%) dogs that underwent unilateral thyroidectomy survived to discharge from the hospital. One hundred-thirteen dogs were lost to follow-up; from the available data, the median survival time was 911 days (95% confidence interval, 704 to 1,466 days).
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that unilateral thyroidectomy in dogs with a naturally occurring thyroid tumor was associated with a perioperative mortality rate of 1.9% and a complication rate of 19.9% and that hemorrhage and aspiration pneumonia were the most common complications. Long-term survival of dogs undergoing unilateral thyroidectomy for the treatment of thyroid tumors was not uncommon.