Gas chromatographic method for the residue analysis of soil exposed to fenazaflor

A method is described for routine determination of residues in soil of 5,6-dichloro-2-trifluoromethylbenzimidazole, the major product formed in soil from the acaricide fenazaflor. The residue is extracted from moistened soil with acidified aqueous methanol. After clean-up by partition the residue is determined by g.l.c. with electron capture detection. Details are presented of the investigations which led to the adoption of this procedure in preference to other variations.     

Salivary and plasma cortisol as an index of stress in goats

Total assayable cortisol in plasma was highly correlated (r = 0.97) with physiologically active free cortisol in plasma after routine management procedures in 1- to 3-weeks-old goats. Transport of adult goats caused significant increases (P less than 0.001) in free cortisol in saliva and in free and total cortisol in plasma. No difference (P greater than 0.05) between concentrations of free cortisol in saliva and in plasma was apparent before or after transport. The results demonstrated that the salivary cortisol method is a useful measure of stress in adult goats, and that the relationship between free and total cortisol in plasma, and the adrenocortical response to transport, appear to be similar in sheep and goats.     

Resistance of Thrips tabaci to pyrethroid and organophosphorus insecticides in Ontario, Canada

Onion thrips, Thrips tabaci Lindeman, were collected from commercial onion fields in 2001, 2002 and 2003 to assess resistance to lambda-cyhalothrin, deltamethrin and diazinon. In 2001, six of eight adult populations were resistant to lambda-cyhalothrin, with resistance ratios (RR) ranging from 2 to 13.1 and four of these were also resistant to deltamethrin, with RR ranging from 19.3 to 120. Three of four adult populations were resistant to diazinon with RR ranging from 2.5 to 165.8. In 2002, four of seven nymphal populations and three of six adult populations were resistant to deltamethrin, with RR ranging from 4.3 to 72.5 and 9.4 to 839.2, respectively. Only one of six nymphal populations and one of five adult populations were resistant to diazinon, with RR of 5.6 and 2.3, respectively. In 2003 diagnostic dose bioassays, 15 of 16 onion thrips populations were resistant to lambda-cyhalothrin and all were resistant to deltamethrin. Eight of the 16 were resistant to diazinon. These results indicate that insecticide resistance is widespread in onion thrips in commercial onion fields in Ontario.     

Occurrence of Salmonella serotype Typhimurium DT104 on a commercial swine farm before, during, and after depopulation and repopulation

OBJECTIVE: To determine whether depopulation-repopulation could be used to eradicate Salmonella serotype Typhimurium DT104 from a commercial swine farm in the midwestern United States. DESIGN: Observational study SAMPLE POPULATION: A commercial swine farm undergoing depopulation-repopulation to eliminate porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae. PROCEDURE: Pooled fecal samples, tissue samples, and serum samples were collected from pigs on the farm before and after depopulation-repopulation. When there were no pigs on the farm, environmental swab specimens were collected for bacterial culture. Serum was analyzed for anti-Salmonella antibodies with an indirect ELISA. Salmonella isolates obtained by bacterial culture of fecal, tissue, and environmental samples were characterized by means of serotyping, phage typing, pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. RESULTS: 167 Salmonella isolates representing 9 serotypes were recovered from the farm. Results of PFGE and antimicrobial susceptibility testing suggested that S. Typhimurium DT104 strain was not eradicated from the farm. However, seroprevalence of anti-Salmonella antibodies and the percentage of pooled fecal samples positive for Salmonella spp were significantly decreased following repopulation. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that depopulation-repopulation in conjunction with stringent cleaning and disinfection, attention to biosecurity procedures, control of other diseases, and changes in feed management may reduce the occurrence of, but likely will not eliminate, Salmonella spp in commercial swine herds.     

Thyroid follicular adenocarcinoma in a ferret

A 5-year-old male castrated ferret was presented to the Washington State University College of Veterinary Medicine for evaluation of progressive hair loss and a large, rapidly growing ventral neck mass. The patient had been diagnosed previously with an insulinoma, which was managed medically. Fine-needle aspirates of the neck mass were performed. The cytologic results were most consistent with epithelial neoplasia, likely a carcinoma; thyroid origin was considered likely based on tumor location and cell morphology. The tumor grew rapidly, and the owners elected euthanasia 1 week after examination. At necropsy, a circumscribed, ovoid mass disrupted the right cervical musculature next to the right lobe of the thyroid gland. Histopathologic evaluation revealed an infiltrative mass consisting of cuboidal cells arranged in solid sheets and irregular follicles enclosing colloid. The cells were large, with prominent nucleoli, and had a high mitotic rate. The histopathologic diagnosis was consistent with thyroid follicular adenocarcinoma. Immunochemical findings confirmed thyroglobulin production by neoplastic cells, but to a lesser extent than in normal ferret thyroid tissue. To our knowledge, this is the first case of thyroid follicular adenocarcinoma to be reported in a ferret, with only 1 other case of thyroid carcinoma, a C-cell carcinoma, described previously.     

Antioxidant and inflammatory responses of healthy horses and horses affected by recurrent airway obstruction to inhaled ozone

REASONS FOR PERFORMING STUDY: Inhaled ozone can induce oxidative injury and airway inflammation. Horses affected by recurrent airway obstruction (RAO) have a decreased pulmonary antioxidant capacity, which may render them more susceptible to oxidative challenge. It is currently unknown whether RAO-affected horses are more susceptible to oxidative stress than those unaffected by RAO. OBJECTIVES: To determine whether ozone exposure induces greater oxidative stress and airway inflammation in RAO-affected horses in remission than in healthy horses. METHODS: Seven healthy control horses and 7 RAO-affected horses were exposed to 0.8 ppm ozone for 2 h at rest. RESULTS: At baseline, bronchoalveolar lavage fluid (BALF) ascorbic acid concentrations were lower in RAO-affected horses than healthy controls. Ozone appeared to preferentially oxidise glutathione rather than ascorbic acid 6 h after exposure. Individual healthy and RAO-affected horses demonstrated oxidation of BALF glutathione after ozone exposure. Overall, RAO-affected horses did not demonstrate increased oxidative stress following ozone exposure, compared with healthy horses. Ozone did not induce significant airway inflammation in either group. CONCLUSIONS: RAO-affected horses in remission are not more sensitive to ozone despite a decreased pulmonary antioxidant capacity. Sensitivity to ozone appears to be independent of initial pulmonary antioxidant status. POTENTIAL RELEVANCE: Horses with high susceptibility to oxidative stress may benefit from antioxidant supplementation.     

Antioxidant supplementation and subsequent oxidative stress of horses during an 80-km endurance race

This study tested the development of oxidative stress and the effects of antioxidant supplementation in an 80-km ride. A precompetition survey revealed that no competitor would participate without vitamin E supplementation; therefore, 46 horses were paired for past performances and randomly assigned to two groups of 23 each for 3 wk of supplementation before the ride. One group (E) was orally supplemented with 5,000 IU of vitamin E per day; the other group (E+C) received that dose of vitamin E plus 7 g/d of vitamin C. Blood samples, temperature, and heart rate were taken the day before the race, at 21 and 56 km during the ride, at completion, and after 20 min of recovery. Plasma was assayed for lipid hydroperoxides, alpha-tocopherol, total ascorbate, albumin, creatine kinase (CK), and aspartate aminotransferase (AST). Total glutathione and glutathione peroxidase activity were determined in red blood cells and white blood cells. Thirty-four horses completed the race, 12 horses (six in E and six in E+C) did not finish for reasons including lameness, metabolic problems, and rider option. Plasma ascorbate was higher (P = 0.045) in the E+C group than in the E group. Other than ascorbate, neither antioxidant status nor CK and AST activities were affected by supplementation with E+C vs. E. Red blood cell glutathione peroxidase, white blood cell total glutathione, lipid hydroperoxides, CK, and AST increased, and red blood cell total glutathione and white blood cell glutathione peroxidase activity decreased with distance (P < 0.001). Positive correlations were found for plasma lipid hydroperoxides on CK (r = 0.25; P = 0.001) and AST (r = 0.33; P < 0.001). These results establish an association between muscle leakage and a cumulative index of oxidative stress.     

Growth rate consists of baseline and systematic deviation components in Thoroughbreds

The objective of this study was to establish a procedure for differentiating a baseline curve from a systematic deviation in weight-age data, and hence to develop a physiological growth model for the Thoroughbred. A total of 2,698 records for 175 foals was obtained during a period of 8 yr (1994 to 2001). Weight-age data were fit with a sigmoid growth equation, W = A(1 + be(-kt))M, where W is BW at age t, A is the asymptotic value of W, b is a scaling parameter that defines the degree of maturity at t = 0, k is a rate constant, and M defines the point of inflection in the sigmoid curve in relation to age. Short-term systematic deviations in the weight-age data were identified by a goodness-of-fit procedure and illustrated in three-dimensional contour plots of the sigmoid equation parameters as they changed upon removal of selected subsets of the data. Based on features of the contour plots, a negative deviation between 210 and 420 d of age was set aside, with the remaining data establishing the baseline data set. The sigmoid growth equation was fit to the baseline data set using a nonlinear mixed model with repeated measures, and indicated a mature weight of 542 +/- 6.2 kg reached at 7 yr. The systematic deviation identified in this weight-age data set is present in other published Thoroughbred growth data and is likely to result in erroneous parameter estimates if not set aside before fitting sigmoid growth equations to the thus-modified weight-age data set. The techniques developed in this study enable identification of short-term systematic deviations in weight-age data and define a realistic baseline growth curve. Differentiation of these two components enables the development of a physiological model of growth that distinguishes between baseline growth and environmental influences, represented respectively, by the baseline curve and the systematic deviation.     

Dynamic performance of the mechanism of an automatically deployable ROPS

The mechanism for an automatically deployable ROPS (AutoROPS) has been designed and tested. This mechanism is part of an innovative project to provide passive protection against rollover fatality to operators of new tractors used in both low-clearance and unrestricted-clearance tasks. The device is a spring-action, telescoping structure that releases on signal to pyrotechnic squibs that actuate release pins. Upper post motion begins when the release pins clear an internal piston. The structure extends until the piston impacts an elastomeric ring and latches at the top position. In lab tests the two-post structure consistently deployed in less than 0.3 s and latched securely. Static load tests of the telescoping structure and field upset tests of the fully functional AutoROPS have been successfully completed.     

Expression of cyclooxygenase-2 in transitional cell carcinoma of the urinary bladder in dogs

OBJECTIVE: To evaluate expression of cyclooxygenase (COX)-1 and COX-2 in the urinary bladder epithelium of clinically normal dogs and in transitional cell carcinoma cells of dogs. ANIMALS: 21 dogs with transitional cell carcinoma of the urinary bladder and 8 dogs with clinically normal urinary bladders. PROCEDURE: COX-1 and COX-2 were evaluated by use of isoform-specific antibodies with standard immunohistochemical methods. RESULT: COX-1, but not COX-2, was constitutively expressed in normal urinary bladder epithelium; however, COX-2 was expressed in neoplastic epithelium in primary tumors and in metastatic lesions of all 21 dogs and in new proliferating blood vessels in 3 dogs. Also, COX-1 was expressed in the neoplastic cells. CONCLUSIONS AND CLINICAL RELEVANCE: Lack of expression of COX-2 in normal bladder epithelium and its substantial expression in transitional cell carcinoma cells suggest that this isoform may be involved in tumor cell growth. Inhibition of COX-2 is a likely mechanism of the antineoplastic effects of non steroidal antiinflammatory drugs.