Effects of equine recombinant interleukin-1alpha and interleukin-1beta on proteoglycan metabolism and prostaglandin E2 synthesis in equine articular cartilage explants

OBJECTIVES: To evaluate the effects of equine recombinant interleukin-1alpha (rEqIL-1alpha) and recombinant interleukin-1beta (rEqIL-1beta) on proteoglycan metabolism and prostaglandin E2 (PGE2) synthesis by equine articular chondrocytes in explant culture. SAMPLE POPULATION: Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse. PROCEDURE: Expression constructs containing cDNA sequences encoding EqIL-1alpha and EqIL-1beta were generated, prokaryotically expressed, and the recombinant protein purified. Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse were separately randomized to receive rEqIL-1alpha or rEqIL-1beta treatments 10 to 500 ng/ml). Proteoglycan release was evaluated by 1,9-dimethylmethylene blue spectrophotometric analysis of explant media glycosaminoglycan (GAG) concentration and release of 35S-sulfate-labeled GAG to explant media. Proteoglycan synthesis was assessed by quantification of 35S-sulfate incorporation into proteoglycan. Explant media PGE2 concentrations were evaluated using a PGE2-specific enzyme-linked immunoassay. Data were collected at 48-hour intervals and normalized by DNA content. RESULTS: Proteoglycan release was induced by rEqIL-1alpha and rEqIL-1beta at concentrations > or =0.1 ng/ml, with 38 to 76% and 88 to 98% of total GAG released by 4 and 6 days, respectively. Inhibition of proteoglycan synthesis (42 to 64%) was observed at IL-1 concentrations > or = 0.1 ng/ml at 2 and 4 days. Increased PGE2 concentrations were observed at IL-1 concentrations > or = 0.1 ng/ml at 2 and 4 days. CONCLUSIONS AND CLINICAL RELEVANCE: The rEqIL-1 induced potent concentration-dependent derangement of equine chondrocyte metabolism in vitro. These findings suggest this model may be suitable for the in vitro study of the pathogenesis and treatment of joint disease in horses.     

Effects of diet restriction on life span and age-related changes in dogs

OBJECTIVE: To evaluate the effects of 25% diet restriction on life span of dogs and on markers of aging. DESIGN: Paired feeding study. ANIMALS: 48 Labrador Retrievers. PROCEDURES: Dogs were paired, and 1 dog in each pair was fed 25% less food than its pair-mate from 8 weeks of age until death. Serum biochemical analyses were performed, body condition was scored, and body composition was measured annually until 12 years of age. Age at onset of chronic disease and median (age when 50% of the dogs were deceased) and maximum (age when 90% of the dogs were deceased) life spans were evaluated. RESULTS: Compared with control dogs, food-restricted dogs weighed less and had lower body fat content and lower serum triglycerides, triiodothyronine, insulin, and glucose concentrations. Median life span was significantly longer for dogs in which food was restricted. The onset of clinical signs of chronic disease generally was delayed for food-restricted dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that 25% restriction in food intake increased median life span and delayed the onset of signs of chronic disease in these dogs.     

Cellular nucleic acids in serum and plasma as new diagnostic tools

Currently, the diagnosis of bovine spongiform encephalopathy is only possible in the brain stem of dead animals. Protease resistant prions are detected in the obex region of the brain stem. However, from a veterinary medical and agricultural point of view the development of an in vivo detection assay is of utmost importance. Because infectious prions are detectable relatively late in the central nervous system during an infection, efforts are made searching for surrogate markers. Besides neuronal proteins that are released into the liquor and blood during neurodegenerative processes or other neuronal diseases, cellular nucleic acids circulating in the plasma or serum are an absolutely new approach for the detection of infectious diseases.     

A low-selenium diet increases thyroxine and decreases 3,5,3'triiodothyronine in the plasma of kittens

The effect of a low-selenium diet on thyroid hormone metabolism was investigated in growing kittens. Twelve specific-pathogen-free kittens with ages ranging from 16 to 18 weeks were divided into two groups of equal number with equal sex distribution in each group. One group was fed a yeast-based low-selenium diet (0.02 mg Se/kg diet) while the other group was fed the same diet supplemented with Na₂SeO₃ at 0.4 mg Se/kg diet for 8 weeks. Food intake, body weight and body weight gain were not affected by the low-Se diet during the study period. However, kittens given the low-Se diet had significantly reduced plasma selenium concentration and glutathione peroxidase activity. Plasma total thyroxine (T4) increased and total 3,5,3'triiodothyronine (T3) decreased significantly in kittens fed the low-Se diet at the end of the study. These results suggest that type I deiodinase in cats is a selenoprotein- or a selenium-dependent enzyme.     

Association of high-speed exercise with racing injury in thoroughbreds

OBJECTIVE: To determine the association between high-speed exercise and risk of injury while racing among Thoroughbreds in Kentucky. DESIGN: Matched case-control study. ANIMALS: 206 Thoroughbreds that sustained a musculoskeletal injury while racing and 412 Thoroughbreds that were not injured during the same races. PROCEDURE: Data regarding official timed workouts and races and the Beyer's numbers for the 3 races before the race during which injury occurred were extracted from past performance charts and compared between injured horses and control horses. RESULTS: For injured horses, cumulative distance of high-speed exercise during the 1- and 2-month periods prior to the race in which injury occurred was significantly less than that of control horses; for either period, a difference of 10 furlongs was associated with approximately 2-fold greater risk of injury. Beyer's numbers were significantly higher for injured horses than for control horses. These effects remained significant after adjusting for age and results of prerace physical inspection. CONCLUSIONS AND CLINICAL RELEVANCE: In Kentucky, injured horses had significantly less cumulative high-speed exercise than did control horses during the 1- and 2-month periods prior to the race in which injury occurred. These results differ from those observed in California. The association of injury with cumulative high-speed exercise appears to vary among regions in the United States.     

In vitro insecticidal effects of fipronil and beta-cyfluthrin on larvae of the blowfly Lucilia sericata

The insecticidal effects of the phenylpyrazole, fipronil, and a pyrethroid, beta-cyfluthrin, on larvae of the blowfly Lucilia sericata were determined in laboratory assays. When first stage larvae of L. sericata were reared on homogenized pig liver which had been treated with known amounts of test compounds, both fipronil and beta-cyfluthrin induced significant levels of mortality compared to acetone and water controls. However, fipronil was approximately 10 times more toxic than beta-cyfluthrin to L. sericata larvae following ingestion. Beta-cyfluthrin had little effect on mortality until concentrations of approximately 0.5 ppm were reached. In contrast, fipronil effected L. sericata mortality at a concentration of 0.05 ppm and 100% mortality was reached by 0.5 ppm. The lethal concentration (LC50) value for beta-cyfluthrin was 1.56 ppm as compared to 0.14 ppm for fipronil. Following contact of first and third stage larvae with cloth impregnated with known amounts of test compound, the mortality profiles of fipronil and beta-cyfluthrin were similar. At short contact times, the LC50 values for fipronil were lower than those for beta-cyfluthrin. However, at the highest contact time evaluated for the first stage larvae, 300 s, there was a reversal in this trend. The results suggest that the phenylpyrazole fipronil may represent a new potential insecticide for development against blowfly strike of sheep.     

Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations and other barriers to adoption

Classical biological control remains the only tool available for permanent ecological and economic management of invasive alien species that flourish through absence of their co‐evolved natural enemies. As such, this approach is recognized as a key tool for alien species management by the Convention on Biological Diversity (CBD), the European and Mediterranean Plant Protection Organization (EPPO) and the European Strategy on Invasive Alien Species (ESIAS). Successful classical biological control programmes abound around the world, despite disproportionate attention being given to occasional and predictable non‐target impacts. Despite more than 130 case histories in Europe against insect pests, no exotic classical biological control agent has been released in the EU against an alien invasive weed. This dearth has occurred in the face of increasing numbers of exotic invasive plants being imported and taking over National Parks, forests and amenity areas in this region, as well as a global increase in the use of classical biological control around the world. This paper reviews potential European weed targets for classical biological control from ecological and socioeconomic perspectives using the criteria of historical biological control success, taxonomic isolation from European native flora, likely availability of biological control agents, invasiveness outside Europe and value to primary industry and horticulture (potential for conflicts of interest). We also review why classical biological control of European exotic plants remains untested, considering problems of funding and public perception. Finally, we consider the regulatory framework that surrounds such biological control activities within constituent countries of the EU to suggest how this approach may be adopted in the future for managing invasive exotic weeds in Europe.