The aim of this study was to determine the pharmacokinetics of amikacin and penicillin G sodium when administered in combination as an intravenous regional limb perfusion (IVRLP) to horses. Seven healthy adult horses underwent an IVRLP in the cephalic vein with 2 g of amikacin sulfate and 10 mill IU of penicillin G sodium diluted to 60 mL in 0.9% saline. A pneumatic tourniquet set at 450 mmHg was left in place for 30 min. Synovial fluid was collected from the metacarpophalangeal joint 35 min and 2, 6, 12, and 24 h after infusion of the antimicrobials. Concentrations of amikacin and penicillin in synovial fluid were quantitated by liquid chromatography tandem-mass spectrometry analysis. Therapeutic concentrations of amikacin and penicillin for equine-susceptible pathogens were achieved in the synovial fluid. Maximum synovial concentrations (Cmax) (mean ± SE) for amikacin and penicillin were 132 ± 33 μg/mL and 8474 ± 5710 ng/mL, respectively. Only 3 horses had detectable levels of penicillin at 6 h and 1 at the 12 h sample. The combination of amikacin with penicillin G sodium via IVDLP resulted in reported therapeutic concentrations of both antibiotics in the synovial fluid. The Cmax:MIC (minimum inhibitory concentration) ratio for amikacin was 8:1 and Time > MIC for penicillin was 6 h. At 24 h, the mean concentration of amikacin was still above 4 μg/mL. Terminal elimination rate constants (T1/2 lambdaz) were 13.6 h and 2.8 h for amikacin and penicillin, respectively. The use of IVDLP with penicillin may therefore not be practical as rapid clearance of penicillin from the synovial fluid requires frequent perfusions to maintain acceptable therapeutic concentrations.

Objective-To investigate age-related and regional differences in estimated metabolite concentrations in the brain of healthy dogs by means of magnetic resonance spectroscopy (MRS). Animals-15 healthy Beagles. Procedures-Dogs were grouped according to age as young (n = 5; all dogs were 2 months old), adult (5; mean age, 4.5 years), or geriatric (5; all dogs were 12 years old). Imaging was performed by use of a 1.5-T MRI system with T1- and T2-weighted spin-echo and fluid-attenuated inversion recovery sequences. Signal intensity measurements for N-acetyl aspartate, creatine, choline, and lactate-alanine (the spectroscopic peaks associated with alanine and lactate could not be reliably differentiated) were determined with MRS, and areas under the spectroscopic peaks (representing concentration estimates) were calculated. Ratios of these metabolite values were compared among age groups and among brain regions with regression analysis. Results-The choline-to-creatine ratio was significantly higher in young dogs, compared with other age groups. The N-acetyl aspartate-to-choline ratio was significantly lower in young dogs and geriatric dogs than in adult dogs. When all age groups were considered, the choline-to-creatine ratio was significantly higher and N-acetyl aspartate-to-choline ratio was significantly lower in the frontal lobe than in all other regions. The N-acetyl aspartate-to-creatine ratio was significantly lower in the cerebellum than in other regions. Conclusions and Clinical Relevance-Metabolite ratios varied significantly among age groups and brain regions in healthy dogs. Future studies should evaluate absolute concentration differences in a larger number of dogs and assess clinical applications in dogs with neurologic diseases.

The goal of the present study was to evaluate the potential use of slow release buprenorphine in sheep. Twelve adult female sheep (6 Dorset and 6 Suffolk, 12 months of age) were used for this project and were divided into 2 experimental groups (n = 6/group comprising 3 Dorset and 3 Suffolk sheep). Sustained release (SR) buprenorphine was administered subcutaneously in the scapular region at a concentration of 0.1 mg/kg body weight (BW) for group 1 and of 0.05 mg/kg BW for group 2. Following blood collections at selected time points, plasma concentrations of buprenorphine was performed by tandem liquid chromatograph-mass spectrometry. Mean buprenorphine concentration was above 0.1 ng/mL at 48 h up to 192 h post-injection for group 1 and it was above 0.1 ng/mL at 48 h up to 72 h post-injection for group 2. In conclusion, a long lasting potential analgesic plasma level of buprenorphine is attained following a single subcutaneous injection of 0.1 mg/kg BW of SR buprenorphine in sheep. However the effective analgesic plasma threshold still needs to be determined in sheep.

Objective—To evaluate the use of a micro-lightguide tissue spectrophotometer for measurement of tissue oxygenation and blood flow in the small and large intestines of horses under anesthesia. Animals—13 adult horses without gastrointestinal disease. Procedures—Horses were anesthetized and placed in dorsal recumbency. Ventral midline laparotomy was performed. Intestinal segments were exteriorized to obtain measurements. Spectrophotometric measurements of tissue oxygenation and regional blood flow of the jejunum and pelvic flexure were obtained under various conditions that were considered to have a potential effect on measurement accuracy. In addition, arterial oxygen saturation at the measuring sites was determined by use of pulse oximetry. Results—12,791 single measurements of oxygen saturation, relative amount of hemoglobin, and blood flow were obtained. Errors occurred in 381 of 12,791 (2.98%) measurements. Most measurement errors occurred when surgical lights were directed at the measuring site; covering the probe with the surgeon's hand did not eliminate this error source. No measurement errors were observed when the probe was positioned on the intestinal wall with room light, at the mesenteric side, or between the mesenteric and antimesenteric side. Values for blood flow had higher variability, and this was most likely caused by motion artifacts of the intestines. Conclusions and Clinical Relevance—The micro-lightguide spectrophotometry system was easy to use on the small and large intestines of horses and provided rapid evaluation of the microcirculation. Results indicated that measurements should be performed with room light only and intestinal motion should be minimized.

Objective-To determine the prevalence of biofilm formation under long-term cell culture conditions in serum samples of dairy cattle, goats, cats, and dogs, and to determine whether there is an association between nanobacteria and biofilm formation. Sample Population-Serum samples of clinically normal animals (313 dairy cattle, 48 goats, 140 dogs, and 44 cats) and animals with various medical conditions (60 dogs and 116 cats). Procedure-Serum was incubated under cell culture conditions and observed for biofilm formation by use of light microscopy, electron microscopy, and spectroscopy. A polymerase chain reaction assay was developed to identify 16S rRNA gene sequences of nanobacteria. Results-Biofilm formation developed in serum samples of 304 of 313 (97%) cattle, 44 of 48 (92%) goats, 44 of 44 (100%) cats, and 126 of 140 (90%) dogs. Prevalence of serum samples with positive results for biofilm formation was not significantly different between cats or dogs with and without medical conditions associated with pathologic extraskeletal calcification processes. Scanning electron microscopy and spectroscopy of biofilm samples revealed small coccoid particles consisting mainly of calcium and phosphate. Polymerase chain reaction assay failed to amplify sequences of nanobacteria. Conclusions and Clinical Relevance-Under longterm cell culture conditions, biofilm made up of aggregates of calcium and phosphate crystals does form in serum samples of clinically normal dairy cattle, goats, cats, and dogs. Disease, however, does not predispose to biofilm formation in serum samples of dogs and cats. Our findings did not support the existence of nanobacteria in serum samples of cattle, goats, cats, and dogs.

During the 1986 lambing season, 33 Michigan sheep producers submitted all lambs that had died before weaning to the Michigan State University Diagnostic Laboratory for necropsy. Inductively coupled argon plasma emission spectroscopy was used to measure 22 elements in the liver of 888 of the lambs submitted. Mean concentrations of each element were established and compared with literature values of established deficient, normal, and toxic concentrations. Mean values in milligrams per kilogram of wet weight were as follows: A1, 3.843; As, less than 1; Ba, 0.176; Ca, 128.2; Cr, 0.778; Cu, 56.82; Fe, 491.6; Hg, less than 2; K, 2,150; Mg, 138.4; Mn, 2.776; Mo, 0.489; Na, 1,384; P, 2,583; Pb, 1,453; Sb, less than 1; Tl, less than 5; Zn, 68.31. In only 11 lambs did the liver contain As, B, Cd, Co, Hg, Sb, Se, or Tl in detectable concentrations.

To investigate the effects of a xylazine infusion during isoflurane anesthesia on global perfusion parameters and gastrointestinal oxygenation and microperfusion, 8 adult warmblood horses were sedated with xylazine and anesthesia induced with midazolam and ketamine. Horses were mechanically ventilated during anesthesia. After 3 h of stable isoflurane anesthesia (FEIso 1.3 Vol %), a xylazine infusion with 1 mg/kg body weight (BW) per hour was started for 1 h and then stopped. Before, during, and after xylazine infusion, heart rate (HR), arterial blood pressure (MAP), cardiac output (CO), central venous pressure (CVP), and pulmonary artery pressure (PAP) were measured and systemic vascular resistance (SVR) was calculated. Arterial blood gases were taken and oxygen delivery (DO2) and alveolar dead space (VDalv) were calculated. Further intestinal oxygen and microperfusion were measured using white light spectroscopy and laser Doppler flowmetry. Surface probes were placed via median laparotomy on the stomach, the jejunum, and the colon. Wilcoxon rank-sum test was used to compare values over time (P < 0.05). During xylazine infusion, MAP, CVP, PAP, SVR, and VDalv increased significantly, whereas CO, DO2, and intestinal microperfusion decreased. Intestinal oxygenation remained unchanged. All parameters returned to pre-xylazine values within 1 h after stopping xylazine infusion. A xylazine infusion during constant isoflurane anesthesia in horses impairs global and intestinal perfusion without changing tissue oxygenation in normoxic healthy horses. Further studies are necessary, however, to evaluate whether a possible reduction of isoflurane concentration by xylazine infusion will ameliorate these negative effects.

A classification of raw bovine’s milk samples according to theirgeographical origin in Peninsular Malaysia by Makmal Kesihatan Awam Veterinar, Department of Veterinary Services Malaysia (DVS). Six hundred bovine milk samples were collected from Perlis, Kedah, Perak, Selangor, Pahang, Negeri Sembilan, Melaka and Johor states by 26 milkcollecting centres under DVS. This study was carried out directly using attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectroscopy method coupled with a multivariate principal component analysis (PCA). The spectra generated by ATR-FTIR were analysed and regions of interest were found in between 3851.651cm-1 until 2700.819 cm-1 and 2419.173 cm-1 until 977.368 cm-1. The absorbance and wavenumber data of the regions were then analysed using PCA and the results show presence of clustering towards theirgeographical origin. ATR-FTIR coupled with multivariate PCA has potential for classifying the geographical origin of raw milk produced within Peninsular Malaysia. This method provides a rapid and nondestructive secondary methodology in milk classification without further sample preparation.

OBJECTIVE To investigate the effects of specific cysteine protease (CP) inhibitors on cytopathic changes to porcine intestinal epithelial cells induced by Tritrichomonas foetus isolated from naturally infected cats. SAMPLE T foetus isolates from 4 naturally infected cats and nontransformed porcine intestinal epithelial cells. PROCEDURES T foetus isolates were treated with or without 0.1 to 1.0mM of the CP inhibitors antipain, cystatin, leupeptin, and chymostatin and the vinyl sulfone inhibitors WRR-483 and K11777. In-gel gelatin zymography was performed to evaluate the effects of these inhibitors on CP activity of T foetus isolates. Each treated or untreated isolate was also cocultured with monolayers of porcine intestinal epithelial cells for 24 hours, and cytopathic effects of T foetus were evaluated by light microscopy and crystal violet spectrophotometry. RESULTS Results of in-gel gelatin zymography suggested an ability of WRR-483, K11777, and cystatin to target specific zones of CP activity of the T foetus isolates. These inhibitors had no effect on T foetus growth, and the cytopathic changes to the intestinal epithelium induced by all 4 T foetus isolates were significantly inhibited. CONCLUSIONS AND CLINICAL RELEVANCE This study revealed that certain protease inhibitors were capable of inhibiting regions of CP activity (which has been suggested to cause intestinal cell damage in cats) in T foetus organisms and of ameliorating T foetus–induced cytopathic changes to porcine intestinal epithelium in vitro. Although additional research is needed, these inhibitors might be useful in the treatment of cats with trichomonosis.