Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Francois Elvinger x
  • Refine by Access: All Content x
Clear All Modify Search


Function of polymorphonuclear leukocytes (pmnl) and proliferation of lymphocytes after stimulation with mitogens were evaluated in vitro at incubation temperatures of 38.5 and 42 C, and after in vivo heat stress of lactating Holstein cows. Cytochrome-c reduction and random migration of pmnl were reduced when cells were preincubated or incubated at 42 C, but high incubation temperature had little or no effect on phagocytosis and killing of Escherichia coli. Proliferation of lymphocytes was reduced when cells were incubated for 60 hours at 42 C after stimulation with phytohemagglutinin, poke-weed mitogen, or concanavalin A. After stimulation with phytohemagglutinin, lymphocytes were most sensitive to high temperature during the first 24 hours of the 60-hour culture period. High incubation temperature had little effect on viability of cells. In vivo heat stress had no significant effect on responses of pmnl in vitro, but the decrease in proliferation of lymphocytes in vitro at high temperature was less when cells were obtained from heat-stressed cows. Total leukocyte counts in blood and somatic cell counts in milk were higher in heat-stressed cows. Results indicate that: exposure to high temperature in vitro can depress responses of pmnl and lymphocytes; apparent adaptive mechanisms induced by in vivo heat stress provide protection from effects of high temperature seen in vitro; and evidence could not be found to support the hypothesis that reduction in immune function is the basis for increases in the incidence of mastitis during the summer.

Free access
in American Journal of Veterinary Research


Objective—To determine the effects of body position on intraocular pressure (IOP) in dogs without glaucoma.

Animals—24 healthy dogs with no evidence of glaucoma.

Procedures—Dogs underwent ophthalmic examinations to ensure that no IOP-affecting ocular diseases were present. Each dog was sequentially placed in dorsal recumbency, sternal recumbency, and sitting position. For each of the 3 positions, IOP in the right eye was measured by use of an applanation tonometer immediately after positioning (0 minutes) and after 3 and 5 minutes had elapsed. The initial body position was randomly assigned; each position followed the other positions an equal number of times, and IOP measurements were initiated immediately after moving from one body position to the next. Proparacaine hydrochloride (0.5%) was applied to the right eye immediately prior to IOP measurements.

Results—Intraocular pressure was affected by body position. During the 5-minute examination, IOP decreased significantly in dogs that were dorsally recumbent or sitting but did not change significantly in dogs that were sternally recumbent. For the 3 positions, overall mean IOP differed significantly at each time point (0, 3, and 5 minutes). Mean IOP in dorsal recumbency was significantly higher than that in sternal recumbency at 0 and at 3 minutes; although the former was also higher than that in sitting position at 3 minutes, that difference was not significant.

Conclusions and Clinical Relevance—Body position affects IOP in dogs. When IOP is measured in dogs, body position should be recorded and consistent among repeat evaluations.

Full access
in American Journal of Veterinary Research


Objective—To evaluate the effect of frequent milkout (FMO) on the outcome of experimentally induced Escherichia coli mastitis in cows.

Design—Randomized complete block study.

Animals—16 Holstein dairy cows.

Procedure—Cows were randomly assigned to 1 of 4 groups and were either not infected and not treated (NI-NT), experimentally infected with E coli and not treated (EC-NT), not infected and FMO (NI-FMO), or experimentally infected with E coli and FMO (EC-FMO). The infected quarter in cows in FMO groups was milked out every 4 hours from 16 to 36 hours and every 6 hours from 36 to 84 hours after challenge, with the aid of oxytocin administration. Somatic cell counts (SCC); times to bacterial, clinical, and systemic cures; and serum concentrations of α-lactalbumin were determined.

Results—Use of FMO did not appear to affect SCC. For EC-NT and EC-FMO groups, mean bacterial cure times were 203 and 159 hours, clinical cure times were 276 and 360 hours, and systemic cure times were 144 and 159 hours, respectively; these times were not significantly different. Concentrations of α-lactalbumin were significantly increased in the EC-NT group at 12 hours and in the NI-FMO group at 36 and 60 hours after challenge, compared with values of cows in other treatment groups.

Conclusions and Clinical Relevance—Compared with results in control cows, FMO does not appear to be an efficacious treatment for experimentally induced moderate to severe E coli mastitis. (J Am Vet Med Assoc 2003;222:63–66)

Full access
in Journal of the American Veterinary Medical Association


Objective—To determine the prevalence of cardiomyopathy and the relationship between cardiomyopathy and heart murmurs in apparently healthy cats.

Design—Cross-sectional study.

Animals—103 privately owned, apparently healthy domestic cats.

Procedures—Cats were physically and echocardiographically examined by 2 investigators independently. Left ventricular wall thickness was determined via 2-dimensional echocardiography in short-axis and long-axis planes. Left ventricular hypertrophy was identified when end-diastolic measurements of the interventricular septum or posterior wall were ≥ 6 mm. Cats with left ventricular hypertrophy but without left ventricular dilatation were considered to have hypertrophic cardiomyopathy (HCM). The associations between heart murmurs and Doppler echocardiographic velocity profiles indicative of dynamic ventricular outflow tract obstruction were evaluated.

Results—Heart murmurs were detected in 16 (15.5%; 95% confidence interval, 9.2% to 24.0%) cats; of these, 5 had cardiomyopathy. Cardiomyopathy was also identified in 16 (15.5%; 95% confidence interval, 9.2% to 24.0%) cats; 15 had HCM, and 1 had arrhythmogenic right ventricular cardiomyopathy. Of the cats with HCM, 11 had segmental left ventricular hypertrophy, 3 had diffuse left ventricular hypertrophy, and 1 had borderline left ventricular hypertrophy with marked systolic anterior motion of the mitral valve. Sensitivity and specificity of auscultatory detection of a heart murmur for diagnosing cardiomyopathy were 31% and 87%, respectively. Echocardiographic evidence of late systolic acceleration within ventricular outflow tracts was associated with the existence of a heart murmur.

Conclusions and Clinical Relevance—Cardiomyopathy was common in the healthy cats evaluated in this study. In apparently healthy cats, detection of a heart murmur is not a reliable indicator of cardiomyopathy.

Full access
in Journal of the American Veterinary Medical Association


Objective—To measure minimum inhibitory concentrations (MIC) of 17 antimicrobials for Escherichia coli isolates from a turkey operation and assess whether small samples provide precise estimates of geometric mean MIC.

Design—Prospective study.

Sample Population—105 clinical isolates from birds and 1,104 fecal isolates from 20 flocks (poults and finisher hens).

Procedure—A Mueller-Hinton broth dilution panel was used to measure MIC, and MIC of fecal and clinical isolates were compared. We drew random samples of 5, 10, 15, 20, 25, 30, 35, 40, and 45 isolates from each finisher flock and between 100 and 105 isolates from 5, 7, 10, and 20 flocks. Antimicrobial usage was determined for enrolled flocks.

Results—Six of 12 poult and 18 of 20 finisher flocks had been treated with antimicrobials, often for respiratory illnesses consistent with colibacillosis. All birds received gentamicin at the hatchery. More fecal than clinical isolates were resistant to ampicillin; however, more clinical isolates were resistant to ciprofloxacin, gentamicin, and sulfamethoxazole. Precise estimates of geometric mean MIC for flocks were obtained when ≥ 15 fecal isolates were obtained per flock and, for the operation, when 105 isolates were obtained from ≥ 7 flocks.

Conclusions and Clinical Relevance—Antimicrobial usage was common and may have contributed to the resistance patterns of isolates. With a modest allocation of laboratory resources, producers can monitor antimicrobial susceptibilities of clinical and fecal E coli to manage risks of antimicrobial usage and resistance. (J Am Vet Med Assoc 2002;221:411–416)

Full access
in Journal of the American Veterinary Medical Association