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Abstract

OBJECTIVE

Compare changes in intra-abdominal pressure (IAP), abdominal perfusion pressure (APP), hemodynamics, and clinicopathological variables in nonpregnant and late-term pregnant queens undergoing elective ovariohysterectomy (OHE) and evaluate the effect of patient positioning on IAP and APP measurements.

ANIMALS

18 late-term pregnant queens and 25 nonpregnant controls.

PROCEDURES

Temperature, heart rate (HR), Doppler blood pressure (DBP), IAP (dorsal and right lateral), PCV, total protein (TP), and lactate were recorded preoperatively, at abdominal wall closure (dorsal IAP only), and postoperatively under general anesthesia. Uterine weight, blood loss, and surgical duration were recorded. Abdominal perfusion pressure was calculated as DBP minus IAP.

RESULTS

Pre- and postoperatively, pregnant queens had lower DBP, APP, and PCV compared to controls (P < 0.001). IAP was higher in pregnant queens preoperatively (P < 0.001). Controls had a decrease in HR and increase in IAP, while both groups had a decrease in body temperature, DBP, APP, and lactate over time (P < 0.05). Pregnant queens had a decrease (P = 0.029), and controls had an increase in TP (P = 0.001). Blood loss and surgical time were greater for pregnant queens (P < 0.001). Dorsal IAP and APP were higher and lower than right lateral measurements (P < 0.001), respectively, and correlation was strong.

CLINICAL RELEVANCE

Hemodynamics and APP are impaired in late-term pregnant queens undergoing OHE, and increased monitoring is warranted. Although strongly correlated, feline IAP and APP measurements in dorsal and right lateral recumbency are not interchangeable.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate the biomechanical properties of the mandibles of cats with experimentally created osteotomies simulating oblique ramus fractures, which were stabilized with malleable L-miniplates with either locking screws [locking construct (LC)] or nonlocking screws [nonlocking construct (NLC)], compared with those for intact mandibles.

SAMPLES

20 mandibles from 10 adult cat cadavers.

PROCEDURES

A block study design was adopted to allocate the mandibles of each cadaver to 2 of the 3 test groups (LC, NLC, or intact mandible). Mandibles within each cadaver were allocated systematically to a test group. For mandibles assigned to an LC and an NLC, a complete oblique osteotomy was performed from the mid rostral aspect of the ramus in a caudoventral direction. All mandibles were loaded in a single-load-to-failure test through cantilever bending. Load and actuator displacement were recorded simultaneously. Mode of failure and radiographic evidence of damage to tooth roots and the mandibular canal were evaluated. Biomechanical properties were compared among the groups.

RESULTS

No iatrogenic tooth root damage was evident, but all mandibles with an LC and an NLC had evidence of screw invasion into the mandibular canal. Plated mandibles had significantly less stiffness and bending moment than intact mandibles. Stiffness was not significantly different between the LC and the NLC; the NLC had a greater bending moment at failure than the LC. The pre-yield stiffness of plated mandibles decreased when the number of screw holes overlapping the mandibular canal increased.

CLINICAL RELEVANCE

The use of a malleable L-miniplate in a caudal mandibular fracture model is feasible. Both the LC and the NLC were inferior mechanically to intact mandibles. Type of construct used did not affect the construct stiffness significantly in tested mandibles.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare the duration of bupivacaine liposome suspension in the dog with that of bupivacaine and dexmedetomidine following a perineural injection.

ANIMALS

8 healthy Beagles.

PROCEDURES

The left sciatic nerve of each dog was randomly assigned to an ultrasound-guided perineural injection with either bupivacaine liposome suspension (BLS) or with 0.5% bupivacaine with dexmedetomidine (1 µg/mL) (BUP-DEX). The contralateral nerve was assigned to the alternate agent. The sensory, motor, and proprioceptive functions were evaluated before the injection (baseline) and at 4, 10, 24, 48, 72, and 96 hours.

RESULTS

The block in 1 limb in the BLS treatment appeared to have failed (data set excluded). The motor scores of 2 individuals could not be evaluated leaving 5 limbs to evaluate in the BLS treatment and 6 in the BUP-DEX.

A total of 6 out of 7 limbs in the BLS achieved a complete sensory block. In 3 out of 5 treatments with BLS, motor block was only partial and in 2 not apparent at all. Proprioceptive block was partial in 5 out of 7 dogs in the BLS treatment. All functions were still completely obliterated at 10 hours in 6 cases in treatment BUP-DEX. All functions were restored in all cases by 96 and 24 hours after administration of BLS and BUP-DEX, respectively.

CLINICAL RELEVANCE

The blockade characteristics of bupivacaine liposome suspension were effective and long lasting. Motor and proprioceptive deficits may be inconsistent over time.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare stress markers, gastrointestinal motility, and behavioral indicators of pain between guinea pigs undergoing pneumoperitoneum with carbon dioxide (CO2) and control guinea pigs.

ANIMALS

Fourteen 4- to 5-month-old intact female Hartley guinea pigs.

PROCEDURES

Guinea pigs were randomized to receive insufflation or serve as controls (anesthesia and abdominal catheter placement without insufflation), with 7 animals/group. Insufflated animals underwent 6 mm Hg of CO2 pneumoperitoneum for 30 minutes. Afterward, results for vital signs, blood glucose, fecal cortisol, appetite, fecal output, and behaviors (via video recording) were compared between the 2 groups.

RESULTS

There was no difference between groups and over time for body temperature, heart rate, fecal output in grams, pellets consumed, blood glucose, and fecal cortisol. Guinea pigs that underwent insufflation had significantly more fecal pellets at 36 hours after the procedure. Several behaviors were expressed similarly between groups and over time, such as body turns, incomplete movement, rearing, lying down, drinking, and hiding. Coprophagy occurred less often in the insufflated versus noninsufflated group at 12 h postprocedure but was similar between groups at other time points. At 60 hours after the procedure, insufflated animals spent less time squinting compared to noninsufflated animals. Other behaviors were differentially expressed over time but not between treatments.

CLINICAL RELEVANCE

Overall, there were no major differences in appetite, stress markers, and behaviors between insufflated and control guinea pigs. CO2 insufflation did not appear to cause undue pain or stress in guinea pigs and may be a reasonable technique to use during laparoscopy.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To describe misoprostol pharmacokinetics and anti-inflammatory efficacy when administered orally or per rectum in endotoxin-challenged horses.

ANIMALS

6 healthy geldings.

PROCEDURES

A randomized 3-treatment crossover design was performed with a minimum washout period of 28 days between treatment arms. Prior to endotoxin challenge (lipopolysaccharide, 30 ng/kg IV over 30 minutes), horses received misoprostol (5 µg/kg once) per os (M-PO) or per rectum (M-PR) or water as control (CON). Clinical parameters were evaluated and blood samples obtained to measure plasma misoprostol free acid concentration, leukocyte counts, and tumor necrosis factor-α (TNFα) and interleukin 6 (IL-6) leukocyte gene expression and serum concentrations.

RESULTS

In the M-PO treatment arm, maximum plasma concentration and area under the concentration-versus-time curve (mean ± SD) were higher (5,209 ± 3,487 pg/mL and 17,998,254 ± 13,194,420 h·pg/mL, respectively) and median (interquartile range) time to maximum concentration (25 min [18 to 34 min]) was longer than in the M-PR treatment arm (854 ± 855 pg/mL; 644,960 ± 558,866 h·pg/mL; 3 min [3 to 3.5 min]). Significant differences in clinical parameters, leukocyte counts, and TNFα or IL-6 gene expression or serum protein concentration were not detected. Downregulation of relative gene expression was appreciated for individual horses in the M-PO and M-PR treatment arms at select time points.

CLINICAL RELEVANCE

Considerable variability in measured parameters was detected among horses within and between treatment arms. Misoprostol absorption and systemic exposure after PO administration differed from previous reports in horses not administered LPS. Investigation of multidose administration of misoprostol is warranted to better evaluate efficacy as an anti-inflammatory therapeutic.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare electroretinographic (ERG) responses obtained in dogs before and after oral administration of gabapentin, trazodone, and a combination of both medications.

ANIMALS

12 clinically normal dogs.

PROCEDURES

A short-protocol ERG with 20 minutes of dark adaption was recorded for all dogs to establish baseline ERG responses. Dogs then received gabapentin (approx 30 mg/kg), trazadone (approx 20 mg/kg or approx 5 mg/kg), or a combination of gabapentin (approx 20 mg/kg) and trazodone (approx 5 mg/kg) orally, and the same ERG protocol was repeated 2 hours later. Dogs were given a washout period of at least 1 week between treatments.

RESULTS

a-Wave amplitudes were significantly (P = 0.018) decreased after administration of the combination of gabapentin and trazodone. b-Wave amplitudes were significantly decreased after administration of the 20-mg/kg dose of trazodone (P = 0.006) and after administration of the combination of gabapentin and trazodone (P = 0.002). Heavier dogs that received higher total doses of trazodone had decreases in a-wave amplitude after administration of the 20-mg/kg dose of trazodone and in b-wave amplitude after administration of the 5-mg/kg dose of trazodone.

CLINICAL RELEVANCE

High doses of trazodone and the combination of gabapentin and trazodone significantly decreased a-wave and b-wave amplitudes in clinically normal dogs. However, the effects on retinal responses had little clinical importance. Therefore, these medications can be used safely in a clinical setting; however, further studies are needed in dogs with retinal disease.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVES

To evaluate a carrageenan-induced inflammatory model in the cockatiel (Nymphicus hollandicus) using weight-bearing load, rotational perch locomotion, thermal threshold withdrawal, and footpad dimensions.

ANIMALS

16 adult cockatiels (8 males and 8 females).

PROCEDURES

Cockatiels were randomly assigned into 2 groups as either treatment (carrageenan injection; n = 8) or control (handling only; 8). Treatment of cockatiels involved unilateral subcutaneous injection of 0.05 mL of 1% lambda carrageenan solution into the left footpad. Control birds were handled in a similar manner without an injection. Following baseline measurements and treatment or control procedures, posttreatment measurements at multiple time points involving weight-bearing perch load (for up to 336 hours), locomotive abilities when placed on a rotating perch (for up to 96 hours), thermal withdrawal threshold (for the 24- to 30-hour period), and both vertical and horizontal left footpad size and degree of swelling (for up to 84 days) were obtained.

RESULTS

Treatment cockatiels had a significant decrease in left foot weight-bearing load and increase in left footpad dimensions and swelling grade over time compared to control cockatiels. Rotational perch locomotion and thermal withdrawal threshold, conversely, did not differ significantly between groups. Cockatiels injected with carrageenan returned to normal weight-bearing within 2 weeks; however, left footpad dimensions did not return to baseline.

CLINICAL RELEVANCE

Carrageenan footpad injection prompts a measurable and grossly visible inflammatory response in the cockatiel. Additionally, it induces alterations in weight-bearing distribution in injected birds. This model provides a method to evaluate inflammation and lameness in small psittacine species.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To investigate the clinical feasibility of attenuation imaging of the hepatic parenchyma in healthy dogs, identify technical factors that influence measured attenuation coefficients, and determine intraobserver repeatability of measurements.

ANIMALS

10 healthy Beagles.

PROCEDURES

Attenuation coefficients were calculated for various measurement sites (left vs central division of the liver), scanning planes (transverse vs sagittal plane), scanning depths (10 to 20 mm vs 20 to 30 mm), scanning approaches (intercostal vs subcostal approach), and breathing conditions (free breathing vs breath holding at end expiration). Intraoperator intraday and interday reliability was assessed by computing intraclass correlation coefficients.

RESULTS

Attenuation coefficients were not influenced significantly by scanning plane (P = .120 to 1.000), measurement site (P = .292 to .848), or breathing condition (P = .166). However, coefficients were significantly (P < .01) less with deeper scanning depths and significantly (P < .05) more for the subcostal approach than the intercostal approach. The intraday and interday intraclass correlation coefficients showed good repeatability (0.799 and 0.771, respectively), regardless of the scanning plane and measurement site. Scanning the central division of the liver with the right intercostal approach at a depth of 10 to 20 mm from the liver capsule yielded good reliability.

CLINICAL RELEVANCE

Attenuation imaging was a feasible technique for evaluating the hepatic parenchyma in healthy dogs with good repeatability. Measured attenuation coefficients were not affected by the scanning plane, measurement site, or breathing condition.

Open access
in American Journal of Veterinary Research

When Drs. Nancy and Jerry Jaax graduated from Kansas State University in the 1970s, they were unaware that their study of emerging diseases would become the subject of the best-selling 1994 novel The Hot Zone by Richard Preston. Today their legacy lives on, with K-State well positioned to become a preeminent institution to advance discovery for transboundary, emerging, and zoonotic diseases. With K-State’s Biosecurity Research Institute (BRI), Centers of Excellence, and USDA National Bio and Agro-Defense Facility (NBAF), K-State is the only US university with biosafety level-1 (BSL-1) through BSL-3 facilities adjacent to a federal facility capable

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine and compare the rate, pattern, and completeness of silver nanoparticle (AgNP) elution in vitro over 7 days from 3 carrier media in PBSS.

SAMPLE

AgNPs in calcium sulfate hemihydrate (CSH) beads, poloxamer 407 gel, and a gelatin sponge.

PROCEDURES

Three carrier media were used to create constructs containing AgNPs (8,500 ng). All constructs were submerged in PBSS and stored at 38°C for 7 days. Samples were collected after 2, 6, 12, 18, 24, 36, 48, 72, 96, 120, 144, and 168 hours, and AgNP concentration was measured with inductively coupled plasma mass spectrometry. Constructs were tested in quadruplicate.

RESULTS

Sustained release of AgNPs was seen from all constructs for a minimum of 72 hours. Release from all constructs was incomplete, with an initial burst during the first 24 hours followed by a time-dependent decrease in elution rate for up to 168 hours. A mixed-effects model showed a significant difference in AgNP release over time (P < .001) and among media (P < .001). AgNP–gel constructs released the largest quantity of AgNPs (8,401.02 ng [98.84%]), followed by AgNP–sponge constructs (1,503.45 ng [17.69%]). Release from AgNP–CSH bead constructs was 87.824 ng (1.03%), with no additional release after 72 hours.

CLINICAL RELEVANCE

Sustained release of AgNPs is possible in vitro, but efficacy against bacterial infections needs to be investigated prior to clinical use.

Open access
in American Journal of Veterinary Research