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Journal Club

Collection of Commentaries on Veterinary, Medical, and Related Literature



ELISA Testing for Common Food Antigens in Four Dry Dog Foods Used in Dietary Elimination Trials
Raditic DM, Remillard RL, Tater KC. Journal of Animal Physiology and Animal Nutrition 2011; 95:90-97.

Over-the-counter (OTC) pet foods that contain exotic protein sources are being marketed on an increasing basis. This study investigated whether common food antigens (ie, soy, poultry, and beef) could be identified in OTC dry dog foods with venison that did not list these ingredients on their labels.

Samples of 4 OTC dry dog foods with venison in the product name were sent to an accredited laboratory that performs enzyme-linked immunosorbent assay (ELISA) testing for the presence of food antigens. In this case, the samples were screened for soy antigens, cooked beef, and poultry striated muscle antigens. The negative control was a therapeutic venison-based dry dog food; the positive controls were 3 OTC dry dog foods with soy, beef, and poultry listed as ingredients on the label.

  • Positive Controls: ELISA was able to detect soy, beef, and poultry proteins in the 3 dry dog foods.
  • Negative Control: No soy, beef, or poultry proteins were detected in the negative control diet.
  • Venison Foods: Of the 4 dry dog foods, soy was detected in 3 and beef was detected in 1 despite the absence of those ingredients on the product label.

Critical Points

  • Increasing numbers of pet foods containing exotic protein sources are now available OTC.
  • This study found that some OTC diets may contain detectable amounts of common food antigens but these ingredients were not listed on the product label.
  • Cross contamination with ingredients not listed on a pet food label can occur at various steps in the manufacturing process.
  • This study suggests that using an OTC pet food for a food elimination trial, even when only novel ingredients are listed on the label, could result in false negative results.

—Kathryn E. Michel, DVM, MS, Diplomate ACVN, University of Pennsylvania


Clinical Evaluation of Non-Surgical Sterilization of Male Cats with Single Intra-Testicular Injection of Calcium Chloride
Jana K, Samanta PK. BMC Veterinary Research 2011; 7:39-54.

Calcium chloride solution of various concentrations was injected directly into the testes of eighteen 9- to 12-month-old cats. These cats were compared with both castrated cats and cats in which only saline was injected into the testes. All cats were castrated 60 days postinjection. Parameters evaluated included physical and behavioral changes, serum indicators of stress, testicular size and histomorphology, and serum and intratesticular testosterone concentrations.

Both groups of cats that had testicular injections showed discomfort in the days following injection, presumably due to increased intratesticular pressure. However, no other significant physical changes or indicators of stress were evident. Testicular size and intratesticular testosterone concentrations were most decreased in the highest concentration treatment group (20% calcium chloride in saline). This high-dose treatment also was associated with testicular necrosis and lack of germ cells on histology and significantly decreased concentration of epididymal spermatozoa.

Critical Points

  • Intratesticular injection exerts a contraceptive effect by causing testicular damage with subsequent loss of germ cells and interstitial cells.
  • Subsequent decline in testosterone should be associated with decreased objectionable sexual behaviors.
  • Intratesticular injection with calcium chloride and local anesthetic was a noninvasive, effective means of contraception in cats in this study. However, some spermatozoa and testosterone were still present at 60 days postinjection.

—Margaret V. Root Kustritz, DVM, PhD, Diplomate ACT, University of Minnesota


Effects of Oral Administration of N-Acetyl-D-Glucosamine on Plasma and Urine Concentrations of Glycosaminoglycans in Cats with Idiopathic Cystitis
Panchaphanpong J, Asawakarn T, Pusoonthornthum R. American Journal of Veterinary Research 2011; 72:843-850.

Cats with naturally occurring idiopathic cystitis (IC) were randomly assigned to receive either 250 mg of N-acetyl-D-glucosamine (NAG) (n = 12) or placebo (n = 7) Q 24 H orally for 28 days. Plasma glycosaminoglycan (GAG) concentrations and urine GAG:creatinine ratios were measured on days 0, 7, 14, 21, 28, and 56. Compared to 10 clinically healthy cats, urine GAG:creatinine ratios were significantly lower in cats with IC on day 0. Although administration of NAG to cats with IC increased urine GAG:creatinine ratios, only the plasma concentrations were significantly increased. Owners of NAG-treated cats with IC reported fewer signs of pain during urination on day 28 of treatment; in addition, hematuria tended to decrease in NAG-treated cats with IC. Previous studies have documented decreased urinary GAG concentrations in cats with IC but this is the first study to describe the effects of oral NAG administration on urinary GAG concentrations. It is likely that decreased urinary GAG concentrations occur secondary to IC but the results of this study suggest further investigation of the effects of oral NAG administration in cats with IC is warranted.

Critical Points

  • Twelve cats with naturally occurring idiopathic cystitis (IC) received 250 mg of N-acetyl-D-glucosamine (NAG) Q 24 H orally for 28 days.
  • On day 0 of the study, the cats with IC had significantly lower glycosaminoglycan (GAG):creatinine ratios than clinically healthy cats.
  • By day 28, the cats with IC that were receiving NAG had:
    • Increased urine GAG:creatinine ratios (however, only plasma concentrations were significantly increased)
    • Fewer signs of pain during urination
    • A tendency for fewer episodes of hematuria.
  • This is the first study to investigate the effects of oral NAG administration of urinary GAG concentrations; the results indicate that further investigation is warranted.

—Gregory F. Grauer, DVM, MS, Diplomate ACVIM (Small Animal Internal Medicine), Kansas State University


Prognostic Significance of Weight Changes During Treatment of Feline Lymphoma
Krick EL, Moore RH, Cohen RB, Sorenmo KU. Journal of Feline Medicine and Surgery 2011; 13:976-988.

Lymphoma is the most common hematopoietic cancer in cats. Poor body condition score (BCS) either at diagnosis or during chemotherapy has recently been associated with shorter lymphoma specific survival (LSS) times. Unfortunately assessment of BCS is very subjective. This study was designed to evaluate the more objective parameter of body weight (BW) (both baseline and changes over time) for prognostic significance in cats with lymphoma undergoing chemotherapy.

Medical records of 209 cats treated at the University of Pennsylvania from 1995 to 2007 were retrospectively evaluated. Baseline BW was not prognostic for LSS, but cats that gained or had stable weight at 1 and 2 months had a significantly longer LSS than cats that lost weight. Cats with large-cell lymphoma were more likely to lose weight during the first month of treatment compared to those with small-cell lymphoma. Additionally, cats with small-cell lymphoma had a significantly longer LSS than cats with large-cell lymphoma. Too few cats (n = 22) had enteral feeding tubes placed to draw significant conclusions about the effects of enteral feeding on weight change and LSS.

Critical Points

  • The first 2 months of treatment may be the optimal time to initiate therapeutic interventions and nutritional support in addition to chemotherapy to decrease weight loss, especially in cats with large-cell lymphoma.
  • Nutritional support alone will not reverse tumor-related weight loss; response to chemotherapy is also vital.
  • Differences in weight loss and LSS patterns between large- and small-cell lymphoma are likely associated with the clinically aggressive nature of large-cell lymphoma.

—Claire R. Sharp, BSc, BVMS(Hons), MS, Diplomate ACVECC, Tufts University