Distribution and isolation of radioactivity from 74As-arsenate and 14C-methanearsonic acid in an aquatic model ecosystem

A model aquatic ecosystem was used to measure the bioaccumulation and distribution of ⁷⁴As-arsenate and ¹⁴C-methanearsonic acid in the following aquatic organisms: algae, Oedogonium cardiacum; daphnids, Daphnia magna; fish, Gambusia affins and catfish, Ictalurus punctatus; and crayfish, Procambarus clarkii, Procambarus sp. Bioaccumulation ratios (BR) for ⁷⁴As ranged from 80 to 480 and 4 to 7, for crayfish, and catfish, respectively, in Experiment I. Bioaccumulation ratios were 5, 127, 34, and 5 for daphnids, Gambusia, algae, and crayfish in Experiment II. Values declined for both crayfish and catfish after they were removed to untreated water. Homogenates of all organisms were extracted sequentially with cold 5% trichloroacetic acid, 75% EtOH, and hot 5% TCA. Distribution of the two arsenicals differed with extractant and biological species. The cold acid extracts of algae, daphnids, and crayfish contained the highest levels of ⁷⁴As. Generally, ¹⁴C was distributed more uniformly among the four fractions and was found at a higher percentage in the residue than was arsenate. By gel filtration chromatography, several compounds were separated from extracts of algae, daphnids, Gambusia, and crayfish treated with ⁷⁴As. These compounds were not arsenate, MSMA, or cacodylic acid. Extracts of MSMA-exposed organisms had one major compound which had the same retention volume (about the same molecular weight) as authentic MSMA. High-molecular-weight material (> 5000) was formed in Gambusia and algae treated with MSMA.     

Dynamics of piscine francisellosis differs amongst tilapia species (Oreochromis spp.) in a controlled challenge with Francisella noatunensis subsp. orientalis

A 25‐week immersion challenge was conducted exposing Oreochromis mossambicus, Oreochromis aureus and Oreochromis urolepis hornorum to Francisella noatunensis subsp. orientalis (Fno). Two populations were compared for each fish species; ‘resident fish’ were defined as fish maintained in tanks since week 0 of challenge, whereas ‘naïve fish’ were defined as fish added to tanks once temperature in water reached <26 °C at 21 weeks post‐challenge. Fno genome equivalents (GEs) in water were similar in all treatments 1 h post‐challenge; however, significantly lower Fno GEs were detected 2 weeks post‐challenge in all tanks, and the only treatment with detectable Fno GE after 4 weeks of challenge were the O. mossambicus tanks. Twenty‐one weeks post‐challenge, naïve fish were stocked with ‘resident’ cohorts. Over a 4‐week period, mortalities occurred consistently only in O. mossambicus naïve cohorts. Overall presence of granulomas in spleen of survivors was similar (>55%) in all resident populations; however, in naïve populations, only O. mossambicus presented granulomas. Similarly, only O. mossambicus presented viable Fno in the spleen of survivors, and Fno GEs were only detected in O. mossambicus, and in resident O. aureus. In conclusion, the results of this study suggest different susceptibility of tilapia species to piscine francisellosis.     

Evaluation of gamma-glutamyl transpeptidase-to-creatinine ratio from spot samples of urine supernatant, as an indicator of urinary enzyme excretion in dogs

gamma-Glutamyl transpeptidase activity was measured accurately in canine urine supernatant without gel filtration and was relatively stable at 4 C for at least 4 days after collection. The urinary gamma-glutamyl transpeptidase-to-creatinine ratio in spot samples was simple and quick to measure and was correlated with the 24-hour enzyme excretion. However, the usefulness of this ratio may be limited by within-day variation, and a questionable theoretical basis for its validity.     

Distribution and degradation of dinitroaniline herbicides in an aquatic ecosystem

The accumulation potential of six, structurally related, dinitroaniline herbicides was investigated in an aquatic ecosystem. The herbicides investigated were trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), profluralin [N-(cyclopropylmethyl)-α,α,α-trifluoro-2,6-dinitro-N-propyl-p-toluidine], dinitramine [N³,N³-diethyl-2,4-dinitro-6-(trifluoromethyl)-m-phenylenediamine], chlornidine [N,N-bis(2-chloroethyl)-2,6-dinitro-p-toluidine], fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], and butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine]. The herbicide (0.1 mg) plus 1 μCi of ¹⁴C-labeled herbicide was adsorbed on 100 g of soil (1 ppm), added to individual aquariums, and flooded with 4 liters of water. Algae, snails, and daphnia were added, and ¹⁴C in water was monitored for 30 days. Fish were added on Day 30, and all components were harvested 3 days later. Bioaccumulation ratios (concentration in organism/concentration in water) for fish depended on the amount of their exposure to sunlight: Aquariums held in the dark had higher ratios for fish (235–755) than did those exposed to sunlight (32–83). Bioaccumulation ratios in the dark for fish based on ¹⁴C from bound soil residues of butralin and profluralin were 76 and 119, respectively. Direct repeated applications of profluralin (without soil) at 4-day intervals resulted in a rapid increase, then a decrease in bioaccumulation ratios for Gambusia, but a continuous increase for catfish.     

Evaluation of a commercial enzyme-linked immunosorbent assay for detection of Borrelia burgdorferi exposure in dogs

OBJECTIVE: To evaluate the effectiveness of a commercially available ELISA kit for detecting antibodies against Borrelia burgdorferi in dogs. SAMPLE POPULATION: Banked sera from 440 military working dogs were used for serologic analyses. PROCEDURE: Serum samples were analyzed for antibodies against B burgdorferi by use of a commercially available ELISA and subsequently by western blot analysis as a confirmatory test. RESULTS: Results from the ELISA indicated that 89 (20%) samples were positive for exposure to B burgdorferi or canine Lyme disease vaccine, and 351 (80%) were negative. Follow-up testing by western blot analysis indicated that results for 109 (25%) samples were positive and 331 (75%) were negative for exposure. All samples that had positive results on the ELISA also had positive results on western blot analysis (true positives). Of the 351 samples that had negative results on the ELISA, only 331 had negative results on western blot analysis (true negatives). The remaining 20 samples had positive results on western blot analysis. By use of a standard 2 x 2 table, it was determined that the ELISA had a sensitivity of 82%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 94%. CONCLUSIONS AND CLINICAL RELEVANCE: The commercial ELISA kit evaluated in this study appeared to lack adequate sensitivity for detecting all potential cases of borreliosis in dogs. The ELISA was also unable to discriminate natural exposure from exposure attributable to vaccination, which could complicate interpretation of positive results and treatment of dogs with clinical signs.     

Comparison of Insulin-Induced Digital Vessel Ring Responses of Laminitic and Clinically Healthy Horses

Hyperinsulinemia leads to insulin resistance of blood vessels and interferes with circulation of laminae of the equine foot. The objective of the study was to compare the digital vessel responses of clinically healthy and laminitic horses with and without experimental induction of insulin resistance. Vessel segments (artery and vein) collected after euthanasia were cut into 3-mm wide rings and were prepared in tissue baths containing Tyrode solution for response studies. Two rings of each vessel type from each horse were used as nonresistant, and two were made insulin resistant. Insulin resistance was induced by incubating the rings with 10-μM bath concentration of insulin. Then, all rings were contracted with phenylephrine (5 μM). When the contraction reached a plateau, insulin (10 μM) was added, and the response monitored for 30 minutes. The response to insulin was calculated as a percentage of the phenylephrine response. The results showed that the responses of the nonresistant rings differed significantly between the groups. However, when all rings were made insulin resistant, the significance between the groups disappeared. In the laminitic group, responses of resistant and nonresistant rings did not differ, whereas in the healthy group, the vessel responses differed significantly. In all experiments, arterial and venous rings followed the same pattern, but the magnitudes were greater in arterial rings. The findings suggest that the vessel responses to insulin are altered in laminitis which could be due to insulin resistance.     

Mandibular condylectomy in a standing horse for treatment for osteoarthritis of the temporomandibular joint

An Irish Sport Horse mare presented for evaluation and treatment of inability to masticate effectively with subsequent severe weight loss. A slowly expanding, firm, nonpainful mass was noted at the left temporomandibular joint. Radiographic examination revealed extensive osteoarthritic changes of this joint. Due to the age and debilitated condition of the horse, along with financial constraints on the owner's behalf, the decision was made to perform a mandibular condylectomy as a standing procedure using sedation and local and regional anaesthesia techniques. The mare tolerated the procedure very well and post operatively improved significantly.