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Abstract

Objective

To characterize potential changes in preprandial plasma amino acid concentrations in cats with naturally acquired chronic renal failure (CRF), compared with healthy cats, and to assess potential effects of the severity of renal failure on plasma amino acid concentrations in these cats.

Animals

62 adult cats.

Procedure

Preprandial plasma amino acid concentrations were evaluated in 38 cats with mild, moderate, or severe CRF and in 24 apparently healthy cats. Effects of severity of renal failure, amount of dietary protein, degree of weight loss, appetite, and body condition on plasma amino acid profiles were evaluated.

Results

Cats with various stages of CRF had significantly (P < 0.05) decreased plasma concentrations of o-hydroxyproline, glutamate, proline, glycine, alanine, tyrosine, tryptophan, and arginine, and significantly increased plasma concentrations of asparagine, citrulline, ornithine, 1-methylhistidine, and 3-methylhistidine. Significant (P < 0.05) alterations in amino acid concentrations also were identified when cats with CRF were grouped by appetite or severity of renal disease. Amount of dietary protein, body condition, or degree of weight loss had no significant effect on plasma amino acid concentrations.

Conclusions

Compared with those in healthy cats, preprandial plasma amino acid profiles in cats with mild, moderate, or severe CRF are abnormal.

Clinical Relevance

Despite frequency of altered plasma amino acid concentrations in cats with CRF, the magnitude of these changes is mild and of little clinical relevance. Short-term use of a commercial protein-restricted diet has no deleterious effects on plasma amino acid concentrations. (Am J Vet Res 1999;60:109–113)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine effects of purified and dry expanded (complex) diets on intestinal structure and function in healthy cats and in a feline model of methotrexate-induced enteritis.

Animals

19 adult specific-pathogen-free cats.

Procedure

Cats were randomized in groups to receive a purified diet intragastrically or a complex diet orally to meet their daily metabolizable energy requirements. After 21 days, cats received either methotrexate (MTX; 10 mg/kg of body weight, IV, n = 12) or saline solution IV (n = 7), and were anesthetized 72 hours later. Celiotomy was performed for aseptic removal of mesenteric lymph nodes, full-thickness biopsy of the gastrointestinal tract, and collection of aortic and portal venous blood samples for determination of arteriovenous amino acid concentrations across the intestine.

Results

MTX was associated with severe enterotoxicosis in cats receiving the purified diet, as manifested by diarrhea (4 of 6 cats) and vomiting (2 of 6 cats). One cat receiving the complex diet developed mild diarrhea, and none of these cats vomited. The purified diet was associated with marked villus blunting in the proximal and distal portions of the duodenum and increased bacterial translocation (3 of 6 cats), whereas none of the cats in the complex diet group developed bacterial translocation after MTX administration. For the cats given saline solution, bacterial translocation occurred in 1 of 4 cats receiving the complex diet versus 2 of 3 cats receiving the purified diet.

Conclusions

Feeding of a complex diet containing intact protein as the nitrogen source abrogated the proximal small intestinal atrophy and bacterial translocation associated with feeding an amino acid-based purified diet.

Clinical Relevance

Use of purified diets containing free amino acids as the only nitrogen source cannot be endorsed in human and animal cancer patients receiving systemic chemotherapy. (Am J Vet Res 1997;58:989–996)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To document gross and microscopic anatomic features of the collateral ligaments of the canine cubital joint and to determine their structural and material properties.

Animals

37 canine cadavers.

Procedure

After measurement of ligament dimensions, the bone-collateral ligament-bone specimens were loaded in tension until failure, using a materials testing machine. Data from the load-displacement curves were used to determine the structural and material properties of the ligaments. Gross anatomic features were studied during dissection of the specimens from the medial collateral ligament (MCL) and lateral collateral ligament (LCL), which then were saved for microscopic examination.

Results

Failure load and stiffness values for the LCL were significantly (P < 0.05) greater than those for the MCL. The LCL had obvious cranial and caudal components that attached to the radius and ulna, respectively. The MCL also had cranial and caudal components; however, the cranial component was indistinct, appearing only as a slight thickening of the joint capsule. The caudal component was more prominent; as it extended distad, it had minor attachments to the interosseous and annular ligaments and attached principally on the caudolateral surface of the proximal portion of the radius. The caudal component did not have substantial attachment to the ulna in any of the specimens studied. Both ligaments were composed of closely packed, parallel fascicles of dense collagen, with scant amounts of fibrocartilage and no detectable elastin.

Conclusions

Gross anatomic features of the collateral ligaments of the canine cubital joint indicate that they provide principal structural support to the joint; microscopic anatomic features are typical of other ligaments. The LCL is stronger and stiffer than the MCL; however, their material properties are similar.

Clinical Relevance

Knowledge of the sites of attachment of collateral ligament components is essential for surgeons undertaking repair or reconstruction of these structures. (Am J Vet Res 1997;58:461–466)

Free access
in American Journal of Veterinary Research

Objective

To assess the prevalence of Clostridium perfringens enterotoxin in feces of dogs with and without diarrhea, and to compare the use of microbial cultures from fecal specimens and evaluation of stained fecal smears for endospores with the presence of enterotoxin as tools for diagnosing C perfringens-associated diarrhea.

Design

Prospective study.

Animals

144 dogs representing hospitalized dogs with (n = 41) or without (50) diarrhea, and clinically normal dogs treated as outpatients (53).

Procedure

Fresh fecal specimens from all dogs were examined as Gram-stained fecal smears to determine numbers of Gram-positive spore-forming rods/100X objective field. Enterotoxin was assayed directly by use of a reverse passive latex agglutination assay. Fecal specimens were plated directly to prereduced egg yolk agar plates and incubated overnight at 37 C in an anaerobic chamber. At 24 hours, up to 3 lecithinase-positive colonies were subcultured to Brucella blood agar to evaluate for double zone hemolysis. Colonies with double zone hemolysis were tested for aerotolerance and Gram-stained.

Results

A significant difference was not detected among groups with respect to the presence of C perfringens as determined by culture, the presence of endospores, and the reaction patterns of fecal enterotoxin assays. An association was not found between number of endospores and the presence of fecal enterotoxin.

Clinical Implications

The presence of C perfringens enterotoxin in feces of dogs, as detected by the latex agglutination assay used in this study, correlates poorly with the number of fecal endospores, regardless of the dog's clinical status. (J Am Vet Med Assoc 1999;214:357–360)

Free access
in Journal of the American Veterinary Medical Association

Objective

To identify risk factors associated with fatal acute pancreatitis in dogs.

Design

Case-control study.

Animals

70 case dogs with clinical evidence and histopathologic confirmation of fatal acute pancreatitis and 104 control dogs that had trauma, underwent necropsy, and did not have histologic evidence of acute pancreatitis.

Procedure

Information on signalment, weight, body condition, medical history, concurrent disease, and results of histopathologic examination was obtained by reviewing medical records. Logistic regression analysis included calculation of univariate and multivariate (adjusted) odds ratios and 95% confidence intervals.

Results and Clinical Implications

Dogs with fatal acute pancreatitis were largely middle- to older-aged dogs. Risk of developing fatal acute pancreatitis was increased by overweight body condition, diabetes mellitus, hyperadrenocorticism, hypothyroidism, prior gastrointestinal tract disease, and epilepsy. Additionally, Yorkshire Terriers were at increased risk, and Labrador Retrievers and Miniature Poodles were at decreased risk, of developing fatal acute pancreatitis. Males and neutered females appeared to have an increased risk of developing fatal acute pancreatitis, compared with sexually intact females. Thrombus formation was more likely in dogs that developed fatal acute pancreatitis than in control dogs. (J Am Vet Med Assoc 1999;214:46–51)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To measure changes in rectal temperature and hematologic, biochemical, blood gas, and acid-base values before and after exercise.

Animals

14 healthy adult Labrador Retrievers.

Procedure

Dogs exercised continuously for 10 minutes by repeatedly retrieving a dummy thrown approximately 40 to 50 yards on land. The ambient temperature during each exercise period was recorded. Rectal temperature, pulse, and respiratory rate were measured; CBC and serum biochemical profile were determined; and arterial blood gas tensions, acid-base status, and plasma lactate and pyruvate concentrations were measured at rest and immediately after exercise. Rectal temperature, pulse, respiratory rate, and lactate and pyruvate concentrations were evaluated at intervals up to 120 minutes after exercise.

Results

Immediately after exercise, rectal temperature increased markedly; ambient temperature did not affect rectal temperature. Arterial blood pH and Pao2 were significantly increased after exercise, and Paco2 and bicarbonate concentration were significantly decreased after exercise. Also, statistically, but not clinically, significant increases were observed in RBC, WBC, and segmented neutrophil counts; hemoglobin, total protein, and serum sodium and potassium concentrations; PCV; anion gap; and creatine kinase activity. Plasma lactate and pyruvate concentrations increased significantly after exercise, but there was no change in the lactate-to-pyruvate ratio.

Conclusion and Clinical Relevance

Reference values for healthy Laborador Retrievers during a standardized exercise protocol were established to compare data obtained from Laborador Retrievers with exercise intolerance and collapse. Important characteristics of lactate and pyruvate metabolism were documented that will enable more precise evaluation of exercise intolerance in this breed. (Am J Vet Res 1999;60:88–92)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine effects of glutamine-supplemented and glutamine-free amino acid-based purified diets, compared with a dry expanded diet, on intestinal structure and function in a model that used cats with methotrexate-induced enteritis.

Animals

18 adult specific-pathogen-free cats.

Procedure

12 cats were given intragastric feedings of an amino acid-based purified diet supplemented with glutamine (7% [wt:wt]) or an isonitrogenous amount of glycine and alanine; 6 cats consumed a dry expanded diet. After 21 days, cats received methotrexate (MTX; 11 mg/kg of body weight, IV). Intestinal permeability testing was performed immediately before and 66 hours after MTX administration. Celiotomy was performed 72 hours after MTX administration for aseptic removal of mesenteric lymph nodes, collection of full-thickness intestinal biopsy specimens, determination of intestinal cellular proliferation, and collection of aortic and portal venous blood samples for determination of arteriovenous amino acid concentrations across the intestine.

Results

Administration of MTX was associated with severe enterotoxicosis manifested as diarrhea (8/12 cats), vomiting (12/12), and positive results for bacterial culture of mesenteric lymph nodes (12/12) in cats receiving the purified diets, independent of glutamine supplementation. Diet did not affect villus tip length and villus surface area in the small intestine or cellular proliferation. Administration of MTX was associated with significantly increased intestinal permeability, which was not attenuated by glutamine supplementation.

Conclusions

Feeding of a glutamine-supplemented amino acid-based purified diet was unable to preserve intestinal function in cats with MTX-induced enteritis.

Clinical Relevance

Intestinal morphologic alterations correlate poorly with intestinal function as measured by means of bacterial translocation and intestinal permeability. (Am J Vet Res 1999;60:755-763)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To assess Doppler tissue imaging (DTI) for evaluating left ventricular diastolic wall motion in healthy cats and cats with cardiomyopathy.

Animals

20 healthy cats, 9 cats with hypertrophic cardiomyopathy (HCM), and 9 cats with unclassified cardiomyopathy (UCM).

Procedure

A pulsed wave DTI sample gate was positioned at a subendocardial region of the left ventricular free wall in the short axis view and at the lateral mitral annulus in the apical 4-chamber view. Indices of diastolic wall motion were measured, including peak diastolic velocity (PDV), mean rate of acceleration and deceleration of the maximal diastolic waveform (MDWaccel and MDWdecel, respectively), and isovolumetric relaxation time (IVRT).

Results

The PDV of cats with HCM and 6 of 9 cats with UCM was significantly decreased, compared with that of healthy cats. In the 3 cats with UCM that had a PDV that was not different from healthy cats, MDWaccel and MDWdecel were greater, and IVRT was shorter than those of healthy cats. The IVRT in cats with HCM was longer than that of other cats.

Conclusions and Clinical Relevance

Indices of diastolic function in cats with HCM, and in many cats with UCM, differed from those of healthy cats and were similar to those reported in humans with HCM and restrictive cardiomyopathy, respectively. However, the hemodynamic abnormality was not the same for all cats with UCM; some cats with an enlarged left atrium and a normal left ventricle (ie, UCM) had abnormal left ventricular wall motion consistent with restrictive cardiomyopathy while others did not. (Am J Vet Res 1999;60:1478–1486)

Free access
in American Journal of Veterinary Research

Summary

Within the past 2 years, a putative causal relationship has been reported between vaccination against rabies and the development of fibrosarcomas at injection sites in cats. A retrospective study was undertaken, involving 345 cats with fibrosarcomas diagnosed between January 1991 and May 1992, to assess the causal hypothesis. Cats with fibrosarcomas developing at body locations where vaccines are typically administered (n = 185) were compared with controls (n = 160) having fibrosarcomas at locations not typically used for vaccination. In cats receiving FeLV vaccination within 2 years of tumorigenesis, the time between vaccination and tumor development was significantly (P = 0.005) shorter for tumors developing at sites where vaccines are typically administered than for tumors at other sites. Univariate analysis, adjusted for age, revealed associations between FeLV vaccination (odds ratio [or] = 2.82; 95% confidence interval [CI] = 1.54 to 5.15), rabies vaccination at the cervical/interscapular region (or = 2.09; 95% CI = 1.01 to 4.31), and rabies vaccination at the femoral region (or = 1.83; 95% CI = 0.65 to 5.10) with fibrosarcoma development at the vaccination site within 1 year of vaccination. Multivariate analysis, adjusted for age and other vaccines, also revealed increased risks after FeLV (or = 5.49; 95% CI = 1.98 to 15.24) and rabies (or = 1.99; 95% CI = 0.72 to 5.54) vaccination. The risk of cats developing fibrosarcoma from a single vaccination in the cervical/interscapular region was almost 50% higher than in cats not receiving vaccines at that site; the risk in cats with 2 vaccinations was approximately 127% higher and the risk with 3 or 4 vaccines was approximately 175% higher. However, the frequency of fibrosarcomas in the population is low (estimated at 20/100,000 cats). In approximately half of the cats in our study, fibrosarcomas were at sites where vaccines conventionally are given, and of those cats, approximately half (depending on vaccine) had previously received a vaccine at the tumor site. Although we believe that veterinarians should not alter their vaccination protocols, precautions in vaccine administration (administering different vaccines at varied sites) and further informed consent (presenting current information in a proper benefit/risk context) appear to be advisable.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare effectiveness and complications associated with peribulbar and retrobulbar anesthesia with bupivacaine in cats.

Animals—6 healthy adult cats.

Procedures—Cats were sedated with dexmedetomidine and received a peribulbar injection of 0.5% bupivacaine (1.5 mL), iopamidol (0.5 mL), and saline (0.9% NaCl) solution (1 mL) or retrobulbar injection of 0.5% bupivacaine (0.75 mL) and iopamidol (0.25 mL) in a crossover study with ≥ 2 weeks between treatments. The contralateral eye was the control. Injectate distribution was evaluated with CT. After atipamezole administration, periocular and corneal sensations, intraocular pressure (IOP), and ocular reflexes and appearance were evaluated for 24 hours.

Results—All peribulbar and 3 of 6 retrobulbar injections resulted in CT evidence of intraconal injectate. Corneal sensation and periocular skin sensation were absent or significantly reduced relative to that for control eyes for 3 hours after peribulbar injection. Mean ± SD IOP immediately after injection was significantly higher for eyes with peribulbar injections (33 ± 12 mm Hg) than for control eyes or eyes with retrobulbar injections (both 14 ± 4 mm Hg) but 10 minutes later decreased to 18 ± 3 mm Hg. Exophthalmos, chemosis, and ptosis were evident in most injected eyes, and irritation was evident in 3 of 6 peribulbar-injected and 1 of 6 retrobulbar-injected eyes. All conditions resolved within 14 hours.

Conclusions and Clinical Relevance—Peribulbar injection resulted in intraconal deposition of bupivicaine in a higher percentage of cats than did retrobulbar injection and induced notable anesthesia relative to that for the control eye; however, IOP increased temporarily.

Full access
in American Journal of Veterinary Research