Serum biochemical, blood gas and antioxidant status in search and rescue dogs before and after simulated fieldwork.

The aim of the study was to assess the physiological and antioxidant status before and after a 4 h search and rescue field exercise, with handlers, under warm-weather conditions performing activities compared to a control group of similarly trained dogs at rest. Serum chemistry demonstrated a decrease in serum sodium (Na) and potassium (K) in both exercising and control groups, however only Na was decreased significantly (P < 0.05) after exercise and hematocrits (HCTs) remained unchanged. The exercise group demonstrated significantly decreased serum phosphorus (P) and magnesium (Mg) compared to pre-exercise values, as did the control group (P < 0.025). There was also a significant increase in creatinine kinase concentrations in the exercise groups (P < 0.025). Serum non-esterified fatty acids were increased only in the exercise group after exercise, suggesting fat mobilization to produce energy. The mean total serum antioxidant potential in searching dogs was no different from the pre- and post-exercise values in the control dogs. Serum vitamin E concentrations did not differ between the two groups, with a decreasing trend in both groups. There was a modest decrease in serum uric acid in the control group, while there was a significant rise after exercise in the searching group (P < 0.01). Multiple changes in serum chemistry, HCTs and blood gases were documented in this study, and were similar to those observed after other endurance activities. The lack of hemoconcentration in this field search exercise suggested that even in extreme environmental conditions (heat and humidity), dogs with access to water do not experience significant dehydration or diminished antioxidant status.

Plasma vitamin D metabolites and C-reactive protein in stage-stop racing endurance sled dogs.

BACKGROUND: Dogs are a unique model for examining the effects of exercise on vitamin D status because of their lack of vitamin D synthesis by UV exposure. In addition, the inflammatory response may be associated with hypovitaminosis D. OBJECTIVES: To investigate the effects of several days of endurance exercise on plasma vitamin D (25-(OH)D3, 24,25-(OH)D3 and 1,25(OH)D3) and serum C-reactive protein (CRP) concentrations in stage-stop racing sled dogs. ANIMALS: 12 racing sled dogs and 8 control dogs. METHODS: Blood was collected before the race and immediately after racing on days 2 and 8. Plasma vitamin D metabolites and serum CRP concentrations were measured. RESULTS: Racing dogs showed a significant increase in 25(OH)D3 on day 2 (P = .027) and day 8 of the race (P < .001), whereas no increases were observed in control dogs. The plasma concentration of 24,25(OH)D3 showed a significant increase by day 8 (P < .001). There were no significant changes in 1,25(OH) D3 concentrations across all time points and groups. Racing dogs had significantly increased CRP concentrations by day 2 (39.3 ± 30.1 µg/mL; P < .001). CONCLUSIONS AND CLINICAL IMPORTANCE: Increases in vitamin D metabolites as well as increases in CRP concentrations were observed in racing sled dogs. This finding was contrary to the hypothesis that decreases in vitamin D status in athletes may be related to the acute phase inflammatory response during exercise. In addition, the increased 24,25(OH)D3 concentrations compared to what is observed in other species suggests metabolic variations in dogs that lead to enhanced disposal of vitamin D.

Detection of sulfur mustard bis (2-chloroethyl) sulfide and metabolites after topical application in the isolated perfused porcine skin flap.

The purpose of this study was to develop an assay to study the flux of sulfur mustard (HD) through the skin and determine if metabolites are formed due to the epidermal metabolism of HD after topical exposure of the isolated perfused porcine skin flap (IPPSF) to 14C-HD. Four IPPSFs were topically dosed with 2.85 mg of 14C-HD in ethanol. Venous perfusate samples were collected and added to a 34% solution of NaCl and snap-frozen to inhibit the metabolism of HD until time for assay. Perfusate samples were extracted using a solid-phase extraction cartridge with ethyl acetate and then assayed using gas chromatography. Two of the 4 IPPSFs showed detectable levels of HD in the venous perfusate 15 min after dosing, with 1 of these 2 IPPSFs showing detectable levels of HD in the perfusate 2 hours after dosing. All 4 IPPSFS had no more than 3 metabolites of HD appearing in the perfusate throughout the 2 hr experiment, with one of the these metabolites identified as thiodiglycol. These experiments showed that little, if any, HD appears in the venous perfusate intact after percutaneous absorption and that epidermal metabolism of HD does occur to a significant degree in the IPPSF.

A microspray nozzle for local administration of liquids or suspensions to lung airways via bronchoscopy.

A microspray nozzle has been developed for the localized administration of solutions or suspensions to discrete pulmonary airway regions via bronchoscopy. Toxicants or tracer particles can be administered to single or multiple, specific lung airway segments. This permits studies of local-airway, whole-lung, and systemic responses to inhaled materials. The nozzle is fabricated by ultra-precision machining, has an overall length of 1 mm, and a diameter small enough to fit in the end of a 1.1-mm inner diameter, 1.2-mm outer diameter catheter. In vitro studies demonstrated the delivery efficiency for 99mTc solutions (98 +/- 1% SD) and for suspensions of 99mTc sulfur colloid or 3-mum 85Sr-labeled microspheres (55 +/- 15%). Photographic and gamma camera images of material deposited in the airways of Beagle dogs demonstrated in vivo that the deposition patterns are compact and uniform. The technique may also have therapeutic medical applications.

A method for measuring nasal and lung uptake of inhaled vapor.

This paper describes apparatus and methods for measuring uptake of inhaled vapors in the nose and lungs of dogs. The system allows sampling of air from the trachea at specific times during inspiration and expiration without surgical manipulation of the animal, thus allowing repeated studies in the same animal. During exposure, the dogs are anesthetized and cyclic respiratory patterns are maintained by means of an external respirator. A pneumotachograph installed in the exposure line is connected to a respiratory monitoring system that both monitors the dog's respiratory pattern and triggers sampling at specific times in the respiratory cycle. Air sampling, both at the nose and within the trachea, can be done during the entire breathing cycle or during specific portions of it. Vapors are sampled at a point just external to the dog's nose and from within the trachea through a modified endotracheal tube. To develop and demonstrate the system, three beagle dogs were exposed to 2,4-dimethylpentane and 1.3-dioxolane at nominal vapor concentrations of 500 ppm; vapor sampling was triggered for the entire inspiratory and expiratory portions of the breathing cycle during 10-min exposures. After correcting data to account for vapor that desorbed from the nasal passages during exhalation (after initially being absorbed in the nose during inhalation), net nasal uptake of 2,4-dimethylpentane was 28.3%; net nasal uptake of 1,3-dioxolane was 66.6%. Lung uptake was 14.0% for 2,4-dimethylpentane and 2.1% for 1,3-dioxolane. The system was developed for use with dogs, but it can be adapted for use with any animal species that can be intubated with endotracheal vapor sampling tubes.