Training vs. racing: A comparison of arrhythmias and the repeatability of findings in Thoroughbred Chuckwagon racehorses.

Arrhythmias are commonly reported in exercising horses, however due to regulatory constraints electrocardiograms (ECGs) are acquired during training but not competition, raising questions about the repeatability of findings. The aims were (1) compare training and competition arrhythmias and (2) describe the repeatability of arrhythmias during maximal-intensity exercise. A convenience sample of 52 healthy Thoroughbreds (aged 8.7 ± 2.5 years) competing in the World Professional Chuckwagon Association were obtained, totaling 152 training or competition ECGs (2-7 ECGs/horse). Speed, heart rate (HR) and arrhythmias (supraventricular premature complex, SVPC; ventricular premature complex, VPC) were examined. Pre- and post-recovery (approximately 6 min) blood samples measured lactate and high-sensitivity troponin-T. Training and competition arrythmias were compared (Friedman's test) and reliability of repeated ECGs assessed (intraclass correlation; P < 0.05). Training vs. competition: Forty horses had clean tracing from training and competition (n = 80 ECGs); the number and type of arrhythmias were not different. In training, VPCs were present in 7/40 horses (median [interquartile range, IQR]/ECG; range; 0 [0,0]; 0-4) and 9/40 horses (0 [0,0]; 0-5) in active-recovery. In competition, VPCs were present in 7/40 horses (0 [0,0]; 0-8) and 8/40 horses (0 [0,0]; 0-5) in active-recovery. Arrhythmias were primarily single premature complexes. Training and competition speed, HR, lactate and troponin-T did not differ however, sampling was too early for peak serum Troponin-T levels. Repeatability: total arrhythmias between serial ECGs did not differ. The reliability to detect SVPCs and VPCs was poor to moderate, and poor, respectively. Overall, the total number of arrhythmias was repeatable, but the reliability of arrhythmia type was poor to moderate.

Prevalence of cardiac arrhythmias and R-R interval variation in healthy Thoroughbred horses during official Chuckwagon races and recovery.

The prevalence and severity of cardiac arrhythmias in healthy racehorses undergoing competition is not well defined. The aim was to characterize arrhythmias in Thoroughbreds participating in official Chuckwagon races and to determine normal beat-to-beat (R-R) variability during supramaximal exercise. Electrocardiograph (ECG) recordings were obtained during pre-race, race, and active-recovery from 82 clinically healthy Thoroughbreds. ECG recordings were analyzed for arrhythmias and mean percent R-R deviation. Plasma lactate and high-sensitivity troponin (hs-cTnT) were also measured. Fifty-two ECGs were included in the analysis. Arrhythmias were seen in 48/52 horses (92%) and were predominantly isolated events. No complex rhythms were observed. During the race, 92% of horses had arrhythmias (81% supraventricular premature complex [SVPC]; 33% ventricular premature complex [VPC]). Eleven percent of racing arrhythmias were VPCs (all singlets except for two couplets). During active-recovery, 58% of horses had arrhythmias (56% SVPC; 15% VPCs): Three horses had VPC couplets and one horse had a VPC triplet. All plasma hs-cTnT were within normal limits. The measured lactate was 28.5 ± 4.5 mmol/L, confirming supramaximal exercise. R-R variation ranged between -9.5 to +18.8% during pre-race (mean heart rate [HR], 155 ± 22 beats per min [bpm]), -27.8 to +45.3% during racing (mean HR, 200 ± 9 bpm) and -16.4 to +40.1% during active-recovery (mean HR, 165 ± 14 bpm). Maximal and 1st percentile R-R shortening and lengthening were significantly greater at race than pre-race and active-recovery (P < 0.0001). Racing and active-recovery maximal R-R lengthening were significantly greater than pre-race (P = 0.0003). Supraventricular premature complexes and VPCs are prevalent in healthy horses undergoing Chuckwagon racing. R-R variation is greater during racing than has previously been described.

Effect of Dexamethasone and Fluticasone on Airway Hyperresponsiveness in Horses With Inflammatory Airway Disease.

BACKGROUND: Airway hyperresponsiveness (AWHR), expressed as hypersensitivity (PC75 RL ) or hyperreactivity (slope of the histamine dose-response curve), is a feature of inflammatory airway disease (IAD) or mild equine asthma in horses. Glucocorticoids are used empirically to treat IAD. OBJECTIVES: To determine whether dexamethasone (DEX) (0.05 mg/kg IM q24h) and inhaled fluticasone (FLUT) (3,000 µg q12h) administered by inhalation are effective in decreasing AWHR, lung inflammation, and clinical signs in horses with IAD. METHODS: A randomized crossover study design was used. Eight horses with IAD were assigned to a treatment group with either DEX or FLUT. Measured outcomes included lung mechanics during bronchoprovocative challenges, bronchoalveolar lavage fluid (BALF) cytology, and scoring of clinical signs during exercise. RESULTS: Dexamethasone and FLUT abolished the increase in RL by 75% at any histamine bronchoprovocative dose in all horses after the first week of treatment. However, after 2 weeks of FLUT treatment, 1 horse redeveloped hypersensitivity. There was a significant decrease in the number of lymphocytes after treatment with both DEX and FLUT (P = .039 for both) but no significant differences in other BALF cell types or total cell counts (P > .05). There was no difference in the scoring of the clinical signs during each treatment and washout period (P > .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Both DEX and FLUT treatments significantly inhibit airway hypersensitivity and hyperreactivity in horses with IAD. There are no significant effects on the clinical signs or the number of inflammatory cells (except lymphocytes) in BALF. The treatments have no residual effect 3 weeks after discontinuation.

A novel arsenic removal process for water using cupric oxide nanoparticles.

Recent studies suggest that the cupric oxide (CuO) nanoparticles effectively adsorb aqueous arsenic species under a wide range of water chemistries. However, to develop CuO nanotechnology to a field application level, further studies are necessary. Batch adsorption kinetic experiments were conducted to determine the time course of uptake of arsenic by CuO nanoparticles. A reactor with CuO nanoparticles was developed to conduct continuous flow-through experiments to filter arsenic from groundwater samples. Groundwater samples spiked with 100 µg/L of arsenic were passed through (1L/h) the flow-through reactor. Samples from the flow-through reactor were collected at a regular interval and analyzed for arsenic and other chemical components (e.g., pH, major and trace elements). The CuO nanoparticles adsorbed with arsenic were regenerated with a sodium hydroxide (NaOH) solution and tested again in the flow-through reactor. Three natural groundwater samples with above 10 µg/L of arsenic were also tested with the flow-through reactor. The arsenic adsorption process by CuO nanoparticles was kinetically rapid and followed the pseudo-second-order rate. The continuous flow-through reactor with CuO nanoparticles was effective in filtering arsenic from spiked or natural groundwater. The regenerated CuO nanoparticles were also effective in filtering arsenic from groundwater. Arsenic mass balance data from regeneration studies suggested that 99% of input arsenic concentration was recovered. The CuO nanoparticle treatment did not show any discernible effects on the chemical quality of groundwater samples. Results of this study suggest that CuO nanoparticles show potential for developing a simple process for field applications to remove arsenic from water.

Circulating endothelial cells in renal transplant recipients.

Circulating endothelial cells (CECs) are a marker of endothelial injury and endothelial dysfunction. We measured CECs in 95 patients with functioning renal transplants at risk of premature cardiovascular (CV) disease and in normal control subjects. We were unable to demonstrate consistent relationships between CEC levels and conventional CV risk factors in transplant recipients. However, CEC levels were increased in patients with a history of rejection. We conclude that CECs are of little use as a marker of CV risk in this population but may be a useful marker to monitor allograft rejection.

Transition to CFC-free metered dose inhalers--into the new millennium.

Metered dose inhalers (MDIs) are the most popular vehicle for drug delivery into the lungs and some 500 million are manufactured each year. All MDIs marketed prior to 1995 contained chlorofluorocarbons (CFC) as a propellant. These are implicated in the depletion of stratospheric ozone and, except for specific exemptions, their production has been banned since 1996 under the terms of the Montreal Protocol. Hydrofluoroalkanes have been identified as suitable alternatives for MDI propellants but their physico-chemical properties differ significantly from CFCs and an extensive redevelopment and testing programme has been required to demonstrate the safety, quality and efficacy of HFA containing MDIs. Hydrofluoroalkanes contribute to global warming but the benefit to human health through continued MDI availability currently outweighs the environmental concern. Several HFA-MDIs have reached the market and the transition to replace existing CFC-MDIs is now underway.

Intact PTH study: shipping frozen vs. unfrozen samples.

DCI Laboratory, Nashville TN compared INCSTAR N-tact PTH SP Kit (INCSTAR Corp., Stillwater, MN, USA) results from renal dialysis patients analyzed on frozen versus unfrozen samples; unfrozen samples were analyzed at 24, 48, and 72 hours post-collection. There was no statistical or clinical difference in the results of the frozen samples and unfrozen samples analyzed at 24 hours. Clinics may now ship unfrozen samples if they arrive within 24 hours.

Induction of a silica air-pouch granuloma in rat.

An inflammatory reaction was induced by the injection of crystalline silica into a subcutaneous air pouch formed on the dorsa of rats. The degree of inflammation depended on the quantity of silica injected and on the time interval between air pouch formation and silica injection. The silica provoked exudation of fluid, accumulation of polymorphonuclear and mononuclear leucocytes and the formation of a granuloma. These parameters reached peak values by day 4 whilst the serum acute phase protein levels peaked on day 1. Cyclophosphamide, indomethacin and prednisolone inhibited fluid accumulation but only cyclophosphamide inhibited cell infiltration. The increase in wet and dry granuloma weight was suppressed only by steroid treatment. The suitability of this model as a screen for anti-inflammatory compounds is discussed.

Studies on type II collagen induced arthritis in mice.

A consistent and reproducible polyarthritis was induced in mice by immunizing them with type II collagen in Complete Freunds adjuvant (CFA) and Bacillus Calmette-Guerin (BCG) vaccine. Several inbred strains of mice were investigated for the ability to develop collagen induced arthritis (CIA). DBA/1 mice (H-2q) produced the highest incidence and the most severe arthritis of all the strains examined. Viable BCG vaccine was essential for the induction of a reproducible disease in this strain. The effects of some anti-inflammatory and anti-rheumatic compounds were examined on the developing and established lesions of CIA. These effects were determined by assessing the paw inflammation using a subjective scoring system and measuring foot weight. Furthermore, levels of serum amyloid P component (SAP) were also determined. Benoxaprofen, cyclophosphamide, indomethacin and prednisolone inhibited the paw inflammation in the developing disease whilst the anti-rheumatic compounds auranofin and D-penicillamine exacerbate the paw inflammation. Cyclophosphamide and prednisolone inhibited the established lesions but only prednisolone prevented the development of further lesions in the established disease. The SAP levels in the prednisolone treated group were also reduced. Auranofin treatment exacerbated the inflammation of both the established and the developing lesions in the same animal. D-penicillamine was inactive in the established disease.