Surgical amputation of a digit and vacuum-assisted-closure (V.A.C.) management in a case of osteomyelitis and wound care in an eastern black rhinoceros (Diceros bicornis michaeli)

A 14-yr-old female eastern black rhinoceros (Diceros bicornis michaeli) presented with progressive suppurative osteomyelitis in her left hind lateral toe. beta-Hemolytic Streptococcus sp. was isolated. The animal was treated with multiple systemic antibiotics, and topical wound cleansing. Repeated debridements and nail trimmings were performed for 5 mo prior to electing amputation. The toe was surgically amputated under general anesthesia between the first and second phalanges. Analgesia was diffused into the wound topically via a catheter and elastomeric pump. The open amputation site was covered with adherent drapes and a negative-pressure wound therapy device provided vacuum-assisted closure (V.A.C.) for 72 hr. Three months later this animal developed a deep dermal ulcer on the lateral aspect of the right hind limb, at the level of the stifle. Methicillin-resistant Staphylococcus aureus was isolated. The wound was managed by initial daily lavage, followed by 1 mo of V.A.C. therapy, with 72 hr between dressing changes. Clinically, this therapy expedited the formation of healthy granulation tissue and overall healing was accelerated. The animal tolerated the machine and bandage changes well via operant conditioning. The use of negative-pressure wound therapy appeared to shorten time to resolution of slow-healing wounds in black rhinoceros.     

Characterization of the pharmacokinetic and pharmacodynamic properties of the angiotensin-converting enzyme inhibitor, enalapril, in horses

The pharmacokinetics of enalapril (0.5 mg/kg i.v.) and the pharmacodynamics of enalapril (0.5 mg/kg PO) in 5 mares were investigated. After single i.v. dosing, concentrations of enalapril and enalaprilat, its active metabolite, were measured. Two weeks later, enalapril was administered by nasogastric tube. Potassium, creatinine, blood urea nitrogen (BUN), enalapril, and enalaprilat concentrations and angiotensin converting enzyme (ACE) activity were measured in serum. In addition, heart rate, blood pressure, digital venous blood gases, and lactate were measured. Two weeks later, enalapril was again administered by nasogastric tube. To mimic activation of the renin-angiotensin-aldosterone system, angiotensin I (0.5 microg/kg) was administered at fixed intervals, followed by blood-pressure and heart-rate measurement. The elimination half lives of enalapril and enalaprilat were 0.59 and 1.25 hours, respectively, after i.v. administration. After PO administration, enalapril and enalaprilat were not detectable in serum. There was a tendency (P = .0625) toward a decrease in ACE activity 45-120 minutes after enalapril administration, but ACE activity suppression was never > 16%. There was a tendency (P = .0625) toward a decrease in mean arterial pressure (MAP) 6-8 hours after enalapril administration. Serum concentrations of potassium, creatinine, and BUN and digital venous blood gases and lactate concentrations did not change. In response to angiotensin I, there was a tendency (P = .0625) toward a decrease in the MAP response 4-24 hours after enalapril administration. Single-dose enalapril at 0.5 mg/kg PO did not demonstrate significant availability, pharmacodynamic effect, or substantial suppression of ACE activity.     

IMAGING DIAGNOSIS: MAGNETIC RESONANCE IMAGING OF A CERVICAL WOODEN FOREIGN BODY IN A DOG

This article describes the discovery of a chronic cervical wooden foreign body ventral to the left transverse processes of the cranial cervical spine using magnetic resonance imaging (MRI) in a dog that presented with chronic neck pain and lameness. The dog did not exhibit dysphagia or chronic draining tracts, the most common signs of the presumed cause, that of a penetrating oropharyngeal foreign body. The foreign body itself was represented on MR images as an oval straight-edged core within an inflammatory tissue reaction. The wood was slightly hyperintense on T2- and isointense on T1-weighted images relative to muscle. Surrounding this was a more conspicuous contrast-enhancing reactive tissue rim that was hyperintense on all pulse sequences. Adjacent musculature also exhibited diffuse edema and contrast enhancement that extended around the left cervical vertebral transverse processes and local intervertebral nerve roots. The foreign body was found to be a wooden stick upon surgical removal. MRI is an excellent method for visualizing the inflammatory tissue reactions associated with soft-tissue foreign bodies because of its contrast resolution and depiction of anatomy in multiple imaging planes.     

Genome-wide association for milk production and lactation curve parameters in Holstein dairy cows

The aim of this study was to identify genomic regions associated with 305-day milk yield and lactation curve parameters on primiparous (n = 9,910) and multiparous (n = 11,158) Holstein cows. The SNP solutions were estimated using a weighted single-step genomic BLUP approach and imputed high-density panel (777k) genotypes. The proportion of genetic variance explained by windows of 50 consecutive SNP (with an average of 165 Kb) was calculated, and regions that accounted for more than 0.50% of the variance were used to search for candidate genes. Estimated heritabilities were 0.37, 0.34, 0.17, 0.12, 0.30 and 0.19, respectively, for 305-day milk yield, peak yield, peak time, ramp, scale and decay for primiparous cows. Genetic correlations of 305-day milk yield with peak yield, peak time, ramp, scale and decay in primiparous cows were 0.99, 0.63, 0.20, 0.97 and −0.52, respectively. The results identified three windows on BTA14 associated with 305-day milk yield and the parameters of lactation curve in primi- and multiparous cows. Previously proposed candidate genes for milk yield supported by this work include GRINA, CYHR1, FOXH1, TONSL, PPP1R16A, ARHGAP39, MAF1, OPLAH and MROH1, whereas newly identified candidate genes are MIR2308, ZNF7, ZNF34, SLURP1, MAFA and KIFC2 (BTA14). The protein lipidation biological process term, which plays a key role in controlling protein localization and function, was identified as the most important term enriched by the identified genes.     

Pharmacokinetic and Phase I Evaluation of Carboplatin in Dogs

Thirty dogs with spontaneously occurring malignant neoplasms were treated monthly with carboplatin (CBDCA) given as a 30-minute intravenous infusion in a dose escalation study. Twenty-eight dogs were considered evaluable for toxicity. The maximally tolerated dose of CBDCA was conceptually defined as that dose, determined by logistic regression analyses of toxicity data, resulting in a 50% incidence of moderate toxicity (MOD₅₀) or a 5% incidence of severe toxicity (SEV₅). Each designated maximally tolerated dose was calculated for the first course of treatment only and for the first and second courses of treatment combined to estimate cumulative drug toxicity. The MOD₅₀ and SEV₅ for the first treatment course were 340 and 278 mg/M², respectively. MOD₅₀ and SEV₅ values for the first plus second treatment courses were 327 and 231 mg/M², respectively. The nadir of neutrophil and platelet counts occurred approximately 14 days after treatment. The mean neutrophil and platelet values for all dogs experiencing myelosuppression during the first two treatment courses were 1541/μL and 62,600/μL, respectively. Nonparametric pharmacokinetic analysis of plasma CBDCA values suggested that half-life (T_1/2), area-under-the-curve and total body clearance (CL_b) were not dose dependent. Volume of distribution (VD_ss) significantly increased with dose only between 100 and 150 mg/M², not between 150 and 300 mg/M². Dose-independent serum CBDCA pharmacokinetic disposition indicates that detailed investigation of tissue CBDCA distribution would be warranted and may identify novel dosing strategies that could improve the therapeutic index of CBDCA by minimizing toxicity. (Journal of Veterinary Internal Medicine 1993; 7:235–240. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Evaluation of iohexol clearance used to estimate glomerular filtration rate in clinically normal foals

OBJECTIVE: To determine whether pharmacokinetic analysis of data derived from a single i.v. dose of iohexol could be used to predict creatinine clearance and evaluate simplified methods for predicting serum clearance of iohexol with data derived from 2 or 3 blood samples in clinically normal foals. ANIMALS: 10 healthy foals. PROCEDURE: Serum disposition of iohexol and exogenous creatinine clearance was determined simultaneously in each foal (5 males and 5 females). A 3-compartment model of iohexol serum disposition was selected via standard methods. Iohexol clearance calculated from the model was compared with creatinine clearance. Separate limited-sample models were created with various combinations of sample times from the terminal slope of the plasma versus time profile for iohexol. Correction factors were determined for the limited-sample models, and iohexol clearance calculated via each method was compared with exogenous creatinine clearance by use of method comparison techniques. RESULTS: Mean exogenous creatinine clearance was 2.17 mL/min/kg. The disposition of iohexol was best described by a 3-compartment open model. Mean clearance value for iohexol was 2.15 mL/min/kg and was not significantly different from mean creatinine clearance. A method for predicting serum iohexol clearance based on a 2-sample protocol (3- and 4-hour samples) was developed. CONCLUSIONS AND CLINICAL RELEVANCE: Iohexol clearance can be used to predict exogenous creatinine clearance and can be determined from 2 blood samples taken after i.v. injection of iohexol. Appropriate correction factors for adult horses and horses with abnormal glomerular filtration rate need to be determined.     

Balloon valvuloplasty of congenital mitral stenosis

Radiographic, echocardiographic, fluoroscopic, and angiographic images from 2 dogs with severe congenital mitral valve stenosis that underwent cardiac catheterization and balloon valvuloplasty are presented. Both dogs displayed systolic doming of the mitral valve leaflets, increased diastolic pressure gradient across the left atrium and ventricle, and decreased mitral inflow E to F slope. Balloon valvuloplasty was performed on both dogs using atrial transeptal puncture.     

Proceedings of the 2013 Joint JSTP/NTP Satellite Symposium

The first joint Japanese Society of Toxicologic Pathology (JSTP) and National Toxicology Program (NTP) Satellite Symposium, entitled “Pathology Potpourri,” was held on January 29^th at Okura Frontier Hotel in Tsukuba, Ibaraki, Japan, in advance of the JSTP’s 29^th Annual Meeting. The goal of this Symposium was to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers’ presentations, including diagnostic or nomenclature issues that were presented, select images that were used for audience voting or discussion, and the voting results. Some lesions and topics covered during the symposium include: treatment-related atypical hepatocellular foci of cellular alteration in B6C3F1 mice; purulent ventriculoencephalitis in a young BALB/c mouse; a subcutaneous malignant schwannoma in a RccHan:WIST rat; spontaneous nasal septum hyalinosis/eosinophilic substance in B6C3F1 mice; a rare pancreatic ductal cell adenoma in a young Lewis rat; eosinophilic crystalline pneumonia in a transgenic mouse model; hyaline glomerulopathy in two female ddY mice; treatment-related intrahepatic erythrocytes in B6C3F1 mice; treatment-related subendothelial hepatocytes in B6C3F1 mice; spontaneous thyroid follicular cell vacuolar degeneration in a cynomolgus monkey; congenital hepatic fibrosis in a 1-year-old cat; a spontaneous adenocarcinoma of the middle ear in a young Crl:CD(SD) rat; and finally a series of cases illustrating some differences between cholangiofibrosis and cholangiocarcinoma in Sprague Dawley and F344 rats.