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SUMMARY

Ten coxofcmoral joints from 5 dog cadavers were used to study the effect of coxofcmoral positioning on passive hip laxity. A material test system was used to measure lateral translation when force was between 20 N of compression and 40 N of distraction. Using the orthogonal coordinate system imposed in this study, neutral position was empirically defined at 15° of extension and 10° of abduction, relative to the plane of the pelvis, and no internal or external rotation of the femur. The hips were mounted in a custom-designed jig that allowed 1 rotational degree of freedom (ie, either flexion extension, adduction/ abduction, or internal/external rotation), while holding the other 2 constant. Lateral translation of the hips was tested at 10° intervals from 30° of flexion to 70° of extension, 40° of adduction to 60° of abduction, and 30° of internal rotation to 40° of external rotation. Lateral displacement was maximal at 10° of extension, 20° of abduction, and 10° of external rotation, approximating the neutral coxofcmoral position during stance. As the hips were rotated into extreme positions, the amount of lateral displacement occurring with the same applied load decreased significantly to 32.0 to 65.3% of the maximal displacement. Determining the position of the hip associated with maximal passive laxity in vitro is essential to the design of a precise and accurate clinical stress-radiographic method to quantitate joint laxity in dogs. Our results confirm earlier work that passive hip joint laxity is at a maximum with the hip approximately in a neutral weight-bearing position.

Free access
in American Journal of Veterinary Research

SUMMARY

Chronic Escherichia coli-associated prostatitis was induced in 16 dogs; 9 noninfected dogs served as controls; and all dogs were vasectomized. Two to 3 weeks after instillation of bacteria directly into the prostate, the urine or prostatic fluid or both from 13 of 16 dogs were culture positive. Enrofloxacin, a fluoroquinolone antimicrobial agent, was administered orally to all dogs during the third or fourth week after surgery, at a dosage of approximately 5 mg/kg of body weight, every 12 hours for 7 days. Serum and prostatic fluid concentrations of enrofloxacin were concurrently measured in all dogs on days 2, 4, and 6 at 2 hours after dosing. Serum and prostatic tissue concentrations of enrofloxacin were concurrently measured in all dogs on day 7, at 1.5, 3, 4.5, and 6 hours after dosing. When values for these samples were compared, using a two-factor anova, significant differences were not found. Use of this dosing regimen of enrofloxacin resulted in prostatic fluid and prostatic tissue concentrations exceeding the minimum inhibitory concentration of most pathogens that cause bacterial prostatitis. In addition, prostatic fluid-to-serum and prostatic tissue-to-serum concentration ratios were greater than 1.0.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate clearance of the vaccine strain, immunologic responses, and potential shedding of Brucella abortus strain RB51 organisms after vaccination of bison calves.

Animals

Fourteen 7-month-old female bison calves.

Procedure

10 bison calves were vaccinated SC with 1.22 × 1010 colony-forming units of B abortus strain RB51. Four bison calves were vaccinated SC with 0.15M NaCl solution. Rectal, vaginal, nasal, and ocular swab specimens were obtained to evaluate potential shedding by vaccinated bison. The superficial cervical lymph node was biopsied to evaluate clearance of the vaccine strain. Lymphocyte proliferative responses to strain RB51 bacteria were evaluated in lymph node cells obtained from biopsy specimens and also in peripheral blood mononuclear cells.

Results

Strain RB51 was recovered from superficial cervical lymph nodes of vaccinates examined 6, 12, and 18 weeks after vaccination (4/4, 3/4, and 1/4, respectively) but not in vaccinates examined at 24 weeks (0/3) after vaccination or nonvaccinates examined at all sample collection times (n = 1 bison/sample period). Serologic, immunologic, and bacterial culture techniques failed to reveal shedding of strain RB51 by vaccinates or infection of nonvaccinated bison. Lymphocyte proliferative responses were evident in lymph node cells and blood mononuclear cells from strain RB51-vaccinated bison beginning 12 weeks after vaccination.

Conclusion

Strain RB51 was cleared from bison by 18 to 24 weeks after vaccination. Bison vaccinated with strain RB51 did not shed the vaccine strain to nonvaccinated bison housed in close proximity. Strain RB51 did not induce antibody responses in bison that would interfere with brucellosis surveillance tests, but did stimulate cell-mediated immunity. (Am J Vet Res 1998;59:410–415)

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine pharmacodynamic and pharmacokinetic properties of clopidogrel and the metabolite SR 26334 in dogs.

Animals—9 mixed-breed dogs.

Procedures—8 dogs received clopidogrel (mean ± SD 1.13 ± 0.17 mg/kg, PO, q 24 h) for 3 days; 5 of these dogs subsequently received a lower dose of clopidogrel (0.5 ± 0.18 mg/kg, PO, q 24 h) for 3 days. Later, 5 dogs received clopidogrel (1.09 ± 0.12 mg/kg, PO, q 24 h) for 5 days. Blood samples were collected for optical platelet aggregometry, citrated native and platelet mapping thrombelastography (TEG), and measurement of plasma drug concentrations. Impedance aggregometry was performed on samples from 3 dogs in each 3-day treatment group.

Results—ADP-induced platelet aggregation decreased (mean ± SD 93 ± 6% and 80 ± 22% of baseline values, respectively) after 72 hours in dogs in both 3-day treatment groups; duration of effect ranged from > 3 to > 7 days. Platelet mapping TEG and impedance aggregometry yielded similar results. Citrated native TEG was not different among groups. Clopidogrel was not detected in any samples; in dogs given 1.13 ± 0.17 mg/kg, maximum concentration of SR 26334 (mean ± SD, 0.206 ± 0.2 μg/mL) was detected 1 hour after administration.

Conclusions and Clinical Relevance—Clopidogrel inhibited ADP-induced platelet aggregation in healthy dogs and may be a viable antiplatelet agent for use in dogs.

Impact for Human Medicine—Pharmacodynamic effects of clopidogrel in dogs were similar to effects reported in humans; clopidogrel may be useful in studies involving dogs used to investigate human disease.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether bovine herpesvirus 1 (BHV1), bovine viral diarrhea (BVDV) virus 1 (BVDV1), or BVDV 2 (BVDV2) were shed after parenteral administration of a multivalent modified-live virus vaccine.

Design—Prospective study.

Animals—28 healthy beef calves and 4 healthy pregnant beef cows.

Procedure—A commercially available modified-live virus multivalent vaccine was administered to steers and heifers (n = 18) that were seronegative to BHV1, BVDV1, and BVDV2. Four seronegative pregnant control cows were held in contact with the vaccinated calves for 103 days. Unvaccinated calves (n = 10) were held as controls in a separate double-fenced pen. Seroconversion was monitored by determining serum neutralization titers after vaccination. Viral shedding and viremia were assessed via analysis of nasal swab specimens and blood by use of polymerase chain reaction (PCR) and reverse transcriptase-PCR assays and virus isolation.

Results—A transient BVDV1 viremia was detected in most vaccinated calves 3 to 10 days after vaccination. All vaccinated calves seroconverted to BVDV1 and BVDV2. Seventeen of 18 vaccinated calves seroconverted to BHV1. Viral shedding was not detected in the vaccinated calves. All control cattle remained seronegative to BHV1, BVDV1, and BVDV2 throughout the study.

Conclusions and Clinical Relevance—Shedding of BHV1, BVDV1, and BVDV2 after vaccination was either nonexistent or undetected and did not result in transmission of BHV1, BVDV1, or BVDV2 vaccine viruses to pregnant contact control cows. (J Am Vet Med Assoc 2003;222:1399–1403)

Full access
in Journal of the American Veterinary Medical Association

Objective

To summarize the radiographic and clinical findings, treatment, and outcome in cattle with osteochondrosis diagnosed radiographically.

Design

Retrospective case series.

Sample Population

29 cattle with radiographic evidence of osteochondrosis.

Procedures

Medical records were reviewed, and owners or referring veterinarians were contacted for outcome assessment. Data were analyzed for potential interactions between osteochondrosis classification (osteochondritis dessicans vs subchondral cyst-like lesions), clinical and radiographic findings, treatment, and outcome, using Fisher’s exact test and descriptive statistics.

Results

Osteochondrosis was associated with young, male, purebred cattle, clinical evidence of lameness, and radiographic evidence of concurrent degenerative joint disease. Osteochondritis dissecans and subchondral cyst-like lesions had similar clinical findings and outcomes but varied significantly in their radiographic distribution among joints. Osteochondrosis often manifests clinically as a unilateral condition, but bilateral lesions were often found (88%) when limbs were radiographically examined. Cattle managed conservatively tended to be culled (within 6 months of diagnosis because of lameness) more often than those managed surgically, despite the lack of treatment bias.

Clinical Implications

Osteochondrosis in cattle is often associated with lameness or degenerative joint disease. Conservative management does not result in a favorable clinical prognosis for long-term, lameness-free survival, and more studies need to be completed to evaluate the efficacy of surgical treatment of osteochondrosis in cattle. (J Am Vet Med Assoc 1997;211:1566–1570)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To establish that female calves vaccinated with Brucella abortus strain RB51 at 3, 5, and 7 months of age are protected against infection and abortion when challenged exposed during their first pregnancy.

Animals

Polled Hereford heifer calves obtained from a brucellosis-free herd.

Procedure

Calves were inoculated SC at 3, 5, or 7 months of age with strain RB51 (n = 26), strain 19 (n = 16), or sterile saline solution (n = 15). Calves were bred at 16 to 17 months of age and challenged exposed during the first pregnancy with virulent B abortus strain 2308.

Results

After vaccination, none of the heifers given strain RB51 developed serum antibodies that reacted in the standard tube agglutination test, but reacted in a dotblot assay, using RB51 antigen. B abortus was cultured from biopsy specimens of superficial cervical lymph nodes in the RB51 and S19 vaccinates at 10 weeks, but not at 12 weeks after vaccination. All 4 heifers that had been vaccinated with RB51 at 3 months of age were protected against infection and abortion when challenged exposed. Vaccination at 5 and 7 months of age gave equivalent protection. Heifers given strain 19 were 95% protected and controls (given saline solution) had a high incidence of infection and abortion.

Conclusions

Strain RB51 is protective at doses comparable to those of strain 19 in calves 3 to 10 months of age.

Clinical Relevance

Immunogenicity and failure to induce antibodies that interfere with the serologic diagnosis of field infections of B abortus make strain RB51 an effective vaccine. (Am J Vet Res 1996;57:1153—1156)

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To evaluate the effects of 2 compounds with α-adrenergic antagonist properties on the urethral pressures of anesthetized, healthy, sexually intact male cats, and to evaluate one of the compounds for effect on striated muscle.

Animals

20 healthy, sexually intact male cats.

Procedure

Cats were anesthetized with halothane, and urethral pressure profilometry was performed before and after treatment. 125l-labeled α-bungarotoxin bound to nicotinic receptors of murine skeletal muscle was used in a competitive binding study with acepromazine maleate.

Results

Acepromazine maleate significantly decreased intraurethral pressures in the preprostatic (19%) and pro-static (21%) regions of the urethra. There was no effect on the postprostatic/penile segment. Acepromazine did not inhibit 125l-labeled α-bungarotoxin binding to nicotinic receptors in murine skeletal muscle. Phenoxybenzamine significantly decreased intraurethral pressures (14%) in the preprostatic region of the urethra only.

Conclusions

Acepromazine maleate and phenoxy-benzamine have effects on the smooth muscle of the urethra of healthy, male cats. Acepromazine has no effect on striated muscle.

Clinical Relevance

α-Adrenergic compounds may be used in the pharmacologic management of feline urinary tract disease. (Am J Vet Res 1996;57:1497-1500)

Free access
in American Journal of Veterinary Research