Search Results

You are looking at 1 - 10 of 13 items for

  • Author or Editor: Luc Duchateau x
  • Refine by Access: Content accessible to me x
Clear All Modify Search

Abstract

Objective—To determine whether proinflammatory mediators and glucocorticoids affect CD62L(L-selectin) expression on peripheral blood neutrophils from cows in various stages of lactation.

Animals—100 healthy dairy cows during early (13.1 ± 0.79 days after parturition; n = 31), peak (58.7 ± 1.64 days after parturition; 31), and mid (137.2 ± 2.59 days after parturition; 38) lactation.

Procedure—In vitro effects of relevant proinflammatory mediators that are released in response to mastitis caused by gram-negative bacteria such as lipopolysaccharide (endotoxin), tumor necrosis factor-α, and platelet-activating factor (PAF) on CD62L expression on bovine neutrophils were assessed by flow cytometry. Influences of cortisol and dexamethasone on CD62L expression on bovine neutrophils were also investigated.

Results—Basal CD62L expression on neutrophils from cows during early, peak, and mid lactation were similar. Lipopolysaccharide and tumor necrosis factor-α had no effect on CD62L expression on neutrophils from cows at any stage of lactation. Conversely, PAF elicited a time- and dose-dependent, down regulatory effect on CD62L expression. However, no differential shedding of CD62L from neutrophils of cows at any stage of lactation were detected. In addition, no effects on CD62L expression on bovine neutrophils after whole blood incubation with cortisol or dexamethasone were observed. Incubation with glucocorticoids did not prevent the down regulatory effect of PAF on CD62L expression.

Conclusions and Clinical Relevance—Comparable basal CD62L expression on bovine neutrophils and equal amounts of CD62L shedding from bovine neutrophils during all stages of lactation suggest that variations in CD62L density are not a likely cause of susceptibility of cows to coliform-induced mastitis during early lactation. (Am J Vet Res 2004;225:1421–1426)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine radiographic vertebral ratio values representing vertebral canal stenosis in Doberman Pinschers with and without clinical signs of caudal cervical spondylomyelopathy (CCSM).

Animals—Doberman Pinschers with (n = 81) and without (39) signs of CCSM.

Procedures—All dogs underwent lateral survey radiography of the cervical vertebral column. Five specific measurements were made at C3 through C7, and from those data, 3 ratios were calculated and analyzed for use in diagnosis of CSSM: canal height-to-vertebral body height ratio (CBHR), canal height-to-vertebral body length ratio (CBLR), and caudal vertebral canal height-to-cranial vertebral canal height ratio (CCHR). The CBHR and CBLR were considered indicators of vertebral canal stenosis, and CCHR described vertebral canal shape.

Results—Compared with Doberman Pinschers without CCSM, mean CBHR and CBLR values were significantly smaller for Doberman Pinschers with CCSM; for CBHR, this difference was evident at each assessed vertebra. The CCHR value for C7 was significantly larger in dogs with CCSM. Receiver operating characteristic statistics did not identify a threshold point that had combined high sensitivity and specificity sufficient to differentiate between Doberman Pinschers with and without CCSM.

Conclusions and Clinical Relevance—Doberman Pinschers with CCSM had vertebral canal stenosis combined with a funnel-shaped vertebral canal at C7 significantly more often than did Doberman Pinschers without CCSM. Despite these significant differences, no reliable threshold ratio values were identified to differentiate groups of dogs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate L-selectin (CD62L) and Mac-1 (CD11b) expression at the surface of blood and milk neutrophils during the early inflammatory response to Escherichia coli-induced mastitis in cows.

Animals—6 healthy Holstein heifers in early lactation.

Procedure—Blood and milk samples were collected before and after intramammary administration of 104 CFU's of E coli in the left mammary gland quarters. Bacterial counts and electrolyte concentrations in milk, rectal temperature, differential blood leukocyte counts, milk somatic cell counts, neutrophil viability, and the expression of CD62L and CD11b on blood and milk neutrophils were determined longitudinally.

Results—Bacteria grew during the first 6 hours after inoculation with a pronounced leukocytic influx. Coincident with neutrophil influx was an increase in CD62L+ and CD11b+ milk neutrophils, as well as an improved viability of milk neutrophils. The peak of the inflammatory reaction was reached approximately 12 hours after E coli inoculation. From that time forward, changes in CD62L and CD11b expression were opposed to each other, with a decrease in CD62L expression and an increase in CD11b expression on blood and milk neutrophils; the magnitude of the differences in CD62L and CD11b expression between blood and milk neutrophils decreased. Percentages of CD62L+ and CD11b+ milk neutrophils increased to percentages that were similar to blood neutrophils (ie, approx 92%).

Conclusions and Clinical Relevance—The presence of adhesion molecules on a large percentage of milk neutrophils during the acute inflammatory response, together with the changes in receptor density, suggest a major role for CD62L and CD11b in neutrophil function during coliform mastitis. (Am J Vet Res 2004;65:1164–1171)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate the use of ultrasonography to assess nonunion of fractures in dogs and to compare results of ultrasonography, radiography, and histologic examination.

Sample Population—8 nonunion fractures in 6 dogs (1 each in 5 dogs and 3 in 1 dog); dogs ranged from 7 to 94 months of age and weighed 6 to 30 kg.

Procedures—Diagnostic assessment consisted of complete clinical and orthopedic examinations, radiography, B-mode (brightness mode) ultrasonography, and power Doppler ultrasonography. Biopsy samples were obtained during surgery for histologic examination. They were stained with H&E and immunolabeled by use of anti-CD31 antibodies. Correlations of power Doppler score, power Doppler count, vessel area, and radiographic prediction with the mean number of vessels counted per hpf were derived.

Results—Radiographically, 7 of 8 nonunion fractures were diagnosed as atrophic and were therefore estimated to be nonviable. Vascularity of nonunion fractures during power Doppler ultrasonography ranged from nonvascularized to highly vascularized. Absolute vessel count during histologic examination ranged from 0 to 63 vessels/hpf; 5 nonunion sites had a mean count of > 10 vessels/hpf. Vascularity during power Doppler ultrasonography was highly correlated with the number of vessels per hpf, whereas the correlation between the radiographic assessment and histologic evaluation was low.

Conclusions and Clinical Relevance—Radiographic prediction of the viability of nonunion fractures underestimated the histologically assessed vascularity of the tissue. Power Doppler ultrasonography provided a more accurate estimation of the viability of the tissue and therefore the necessity for debridement and autografts during revision surgery.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To examine mRNA expression of cytokines in synovial fluid (SF) cells from dogs with cranial cruciate ligament (CrCL) rupture and medial patellar luxation (MPL) and determine mRNA expression for 3 joints (affected stifle, unaffected contralateral stifle, and left shoulder joints) in dogs with unilateral CrCL rupture.

Sample Population—29 stifle joints with CrCL rupture (29 dogs), 8 stifle joints with MPL (7 dogs), and 24 normal stifle joints (16 clinically normal dogs).

Procedures—Immediately before reconstructive surgery, SF was aspirated from the cruciate-deficient stifle joint or stifle joint with MPL. Fourteen of 29 dogs had unilateral CrCL rupture; SF was also aspirated from the unaffected contralateral stifle joint and left shoulder joint. Those 14 dogs were examined 6 and 12 months after reconstructive surgery. Total RNA was extracted from SF cells and reverse transcription–PCR assay was performed to obtain cDNA. Canine-specific cytokine mRNA expression was determined by use of a real-time PCR assay.

Results—Interleukin (IL)-8 and -10 and interferon-G expression differed significantly between dogs with arthropathies and dogs with normal stifle joints. For the 14 dogs with unilateral CrCL rupture, a significant difference was found for IL-8 expression. Before reconstructive surgery, IL-8 expression differed significantly between the affected stifle joint and left shoulder joint or contralateral stifle joint. Six months after surgery, IL-8 expression was significantly increased in the unaffected contralateral stifle joint, compared with the shoulder joint.

Conclusions and Clinical Relevance—No conclusions can be made regarding the role of the examined cytokines in initiation of CrCL disease.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess long-term effects and risk factors for the efficacy of hyperimmunization protocols against infectious bovine rhinotracheitis (IBR) during a longitudinal field study of dairy and dairy-beef mixed farms.

Animals—Approximately 7,700 cows from 72 farms.

Procedures—Farms were assigned to 3 treatment groups (hyperimmunization groups [HIGs] 1 and 2, which were hyperimmunized with glycoprotein E [gE]–deleted marker vaccines, and a nonintervention group [NIG]). Cattle in HIG 1 were initially vaccinated with an attenuated vaccine, whereas cattle in HIG 2 were initially vaccinated with an inactivated-virus vaccine. Cattle in both HIGs received booster inoculations with inactivated-virus vaccines at 6-month intervals. The risk for gE seroconversion was compared among experimental groups via a shared frailty model with a piecewise constant baseline risk to correct for seasonal and secular effects.

Results—Risk for gE seroconversion significantly decreased over time for the HIGs, compared with the NIG. Seasonal changes in the risk of gE seroconversion were detected, with a higher risk during winter periods, compared with grazing periods. No significant difference was detected between HIGs 1 and 2. The only significant risk factor was the number of buildings for cattle on a farm; the higher the number of buildings, the lower the risk for gE seroconversion. Prevalence of IBR decreased over time in both HIGs but remained constant or increased in the NIG.

Conclusions and Clinical Relevance—Hyperimmunization via repeated administration of attenuated and inactivated-virus gE-deleted marker vaccines as well as inactivated-virus vaccines may provide a method for control of IBR.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the feasibility of quantitative contrast-enhanced ultrasonography (CEUS) for detection of changes in renal blood flow in dogs before and after hydrocortisone administration.

Animals—11 Beagles

Procedure—Dogs were randomly assigned to 2 treatment groups: oral administration of hydrocortisone (9.6 mg/kg; n = 6) or a placebo (5; control group) twice a day for 4 months, after which the dose was tapered until treatment cessation at 6 months. Before treatment began and at 1, 4, and 6 months after, CEUS of the left kidney was performed by IV injection of ultrasonography microbubbles. Images were digitized, and time-intensity curves were generated from regions of interest in the renal cortex and medulla. Changes in blood flow were determined as measured via contrast agent (baseline [background] intensity, peak ntensity, area under the curve, arrival time of contrast agent, time-to-peak intensity, and speed of contrast agent transport).

Results—Significant increases in peak intensity, compared with that in control dogs, were observed in the renal cortex and medulla of hydrocortisone-treated dogs 1 and 4 months after treatment began. Baseline intensity changed similarly. A significant increase from control values was also apparent in area under the curve for the renal cortex 4 months after hydrocortisone treatment began and in the renal medulla 1 and 4 months after treatment began. A significant time effect with typical time course was observed, corresponding with the period during which hydrocortisone was administered. No difference was evident in the other variables between treated and control dogs.

Conclusions and Clinical Relevance—Quantitative CEUS allowed detection of differences in certain markers of renal blood flow between dogs treated orally with and without hydrocortisone. Additional studies are needed to investigate the usefulness of quantitative CEUS in the diagnosis of diffuse renal lesions.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To describe the contrast-enhanced ultrasonographic characteristics and vascular patterns of adrenal gland tumors in dogs and determine whether those features are indicative of malignancy or histologic type of tumor.

Animals—14 dogs with 16 adrenal gland lesions (10 carcinomas [8 dogs], 3 adenomas [3 dogs], and 3 pheochromocytomas [3 dogs]).

Procedures—Unsedated dogs with adrenal gland lesions underwent B-mode ultrasonography and contrast-enhanced ultrasonography ≤ 48 hours before adrenalectomy; contrast-enhanced ultrasonographic examinations were video-recorded. Macroscopic evaluation of the adrenal gland lesions and histologic examination of removed adrenal gland tissues were subsequently performed. Surgical and histopathologic findings and the ultrasonographic and contrast-enhanced ultrasonographic characteristics were recorded for the various tumor types. Time-intensity curves were generated from the contrast-enhanced ultrasonographic recordings and used to calculate regional blood volume (value proportional to area under the curve) and mean transit time (time the lesion began to enhance to the half-peak intensity).

Results—In adrenal gland carcinomas, tortuous feeding vessels were noticeable during the arterial and venous phases of contrast enhancement. Heterogeneity of contrast enhancement was evident only in malignant tumors. Compared with adenomas, adrenal gland carcinomas and pheochromocytomas had significantly less regional blood volume. Mean transit times were significantly shorter in adrenal gland carcinomas and pheochromocytomas than in adenomas.

Conclusions and Clinical Relevance—For dogs, evaluation of the vascular pattern and contrast-enhancement characteristics of adrenal gland tumors by means of contrast-enhanced ultrasonography may be useful in assessment of malignancy and tumor type.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate the physiologic endocrine effects of food intake and food withholding via measurement of the circulating concentrations of acylated ghrelin, growth hormone (GH), insulin–like growth factor-I (IGF-I), glucose, and insulin when food was administered at the usual time, after 1 day's withholding, after 3 days' withholding and after refeeding the next day in healthy Beagles.

Animals—9 healthy Beagles.

Procedures—Blood samples were collected from 8:30 AM to 5 PM from Beagles when food was administered as usual at 10 AM, after 1 day's withholding, after 3 days' withholding, and after refeeding at 10 AM the next day.

Results—Overall mean plasma ghrelin concentrations were significantly lower when food was administered than after food withholding. Overall mean plasma GH and IGF-I concentrations did not differ significantly among the 4 periods. Circulating overall mean glucose and insulin concentrations were significantly higher after refeeding, compared with the 3 other periods.

Conclusions and Clinical Relevance—In dogs, food withholding and food intake were associated with higher and lower circulating ghrelin concentrations, respectively, suggesting that, in dogs, ghrelin participates in the control of feeding behavior and energy homeostasis. Changes in plasma ghrelin concentrations were not associated with similar changes in plasma GH concentrations, whereas insulin and glucose concentrations appeared to change reciprocally with the ghrelin concentrations.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the spectrum and frequency of abnormalities for low-field magnetic resonance imaging (MRI) examinations of clinically normal Doberman Pinschers and Foxhounds.

Animals—37 clinically normal dogs (20 Doberman Pinschers and 17 Foxhounds).

Procedures—For each dog, MRI of the cervical vertebrae (sagittal, dorsal, and transverse T1- and T2-weighted images) was performed. Variables assessed were intervertebral disk degeneration, disk-associated compression, compression of the dorsal portion of the spinal cord, vertebral body abnormalities, and changes in intraparenchymal signal intensity. Associations between these variables and age, breed, sex, and location of the assessed intervertebral disk spaces were evaluated.

Results—Severe MRI abnormalities were detected in 17 dogs, including complete disk degeneration (n = 4 dogs), spinal cord compression (3), or both (10). Vertebral body abnormalities were detected in 8 dogs, and hyperintense signal intensity was detected in 2 dogs. Severity of disk degeneration and disk-associated compression was significantly associated with increased age. There was a significant association between disk degeneration, disk-as-sociated compression, and compression of the dorsal aspect of the spinal cord and location of the assessed intervertebral disk space, with the intervertebral disk spaces in the caudal portion of the cervical region being more severely affected.

Conclusions and Clinical Relevance—Abnormalities were commonly seen on MRI examinations of the caudal portion of the cervical vertebral column and spinal cord of clinically normal Doberman Pinchers and Foxhounds. Such lesions were probably part of the typical spinal cord degeneration associated with the aging process of dogs.

Full access
in American Journal of Veterinary Research