Publications by authors named "Suann C"

The administration of prohibited substances has been used in agricultural show competitions and animal racing industries to gain unfair competitive advantages. We report the first large prospectively designed descriptive study of drug testing in four species (n = 1,598) over a 23 year period. 4.

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Hemapolin (2α,3α-epithio-17α-methyl-5α-androstan-17β-ol) is a designer steroid that is an ingredient in several "dietary" and "nutritional" supplements available online. As an unusual chemical modification to the steroid A-ring could allow this compound to pass through antidoping screens undetected, the metabolism of hemapolin was investigated by an in vivo equine drug administration study coupled with GC-MS analysis. Following administration of synthetically prepared hemapolin to a thoroughbred horse, madol (17α-methyl-5α-androst-2-en-17β-ol), reduced and dihydroxylated madol (17α-methyl-5α-androstane-2β,3α,17β-triol), and the isomeric enone metabolites 17β-hydroxy-17α-methyl-5α-androst-3-en-2-one and 17β-hydroxy-17α-methyl-5α-androst-2-en-4-one, were detected and confirmed in equine urine extracts by comparison with a library of synthetically derived reference materials.

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The use of testosterone and its pro-drugs, such as dehydroepiandrosterone (DHEA), is currently regulated in horseracing by the application of international testosterone thresholds. However, additional steroidomic approaches, such as steroid ratios, to distinguish overall adrenal stimulation from drug administrations and an equine biological passport for longitudinal steroid profiling of individual animals could be advantageous in equine doping testing. Thus, DHEA concentrations and related ratios (testosterone [T] to DHEA and DHEA to epitestosterone [E]) were assessed in the reference population by quantitative analysis of 200 post-race gelding urine samples using liquid chromatography-tandem mass spectrometry.

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Detection of testosterone and/or its pro-drugs in the gelding is currently regulated by the application of an international threshold for urinary testosterone of 20 ng/mL. The use of steroid ratios may provide a useful supplementary approach to aid in differentiating between the administration of these steroids and unusual physiological conditions that may result in atypically high testosterone concentrations. In the current study, an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed to quantify testosterone (T) and epitestosterone (E).

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Furazadrol ([1',2']isoxazolo[4',5':2,3]-5α-androstan-17β-ol) is a designer anabolic androgenic steroid that is readily available via the internet. It contains an isoxazole fused to the steroid A-ring which offers metabolic stability and noteworthy anabolic activity raising concerns over the potential for abuse of this compound in equine sports. The metabolism of furazadrol was studied by in vivo and in vitro methods for the first time.

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Over recent years threats to racing have expanded to include naturally occurring biological molecules, such as peptides and proteins, and their synthetic analogues. Traditionally, antibodies have been used to enable detection of these compounds as they allow purification and concentration of the analyte of interest. The rapid expansion of peptide-based therapeutics necessitates a similarly rapid development of suitable antibodies or other means of enrichment.

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Three biosecurity and relief-and-recovery initiatives adopted by the NSW horse racing industries reduced the economic and social disruption caused by the disease and subsequent movement controls during the 2007 Australian equine influenza (EI) incursion. The first was the creation of biosecure horse training and racing precincts around the Sydney area to permit racing to continue with healthy horses. Infection was excluded for 3-5 weeks and race meetings were conducted safely during this period.

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An investigation was conducted into the stereochemistry of the equine urinary metabolites of 17alpha-methyltestosterone observed after oral administration. Standards of the complete range of C3/C5/C16 stereoisomeric 17alpha-methylandrostane-3,17beta-diols, 17alpha-methylandrostane-3,16,17beta-triols and 17alpha-hydroxymethylandrostane-3,17beta-diols were purchased or synthesised, and were used to unequivocally identify the absolute structures of the metabolites. Phase I metabolism was found to involve combinations of Delta(4)-3-ketone reduction with both 5alpha,3beta- and 5beta,3alpha-stereochemistry, hydroxylation at C16 with both 16alpha- and 16beta-stereochemistry and hydroxylation of the 17alpha-methyl substituent.

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A method was developed for the analysis of the synthetic progestin 17alpha-hydroxyprogesterone caproate in equine plasma following its administration by intramuscular injection. The method employed a reversed-phase solid-phase extraction followed by enol-trimethylsilylation and analysis by gas chromatography/tandem mass spectrometry. The intact ester was detectable in the plasma for up to 2 weeks after a single therapeutic dose, and was found to be stable in equine whole blood for at least 2 months.

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Article Synopsis
  • A new screening test has been developed using an enzyme-linked immunosorbent assay (ELISA) to detect various anabolic steroid metabolites in horse urine, addressing concerns of steroid misuse in horse racing.
  • The test specifically focused on 16beta-hydroxymestanolone and was created by raising polyclonal antibodies in sheep, showing strong cross-reactivity with various related steroid compounds.
  • Analysis of horse urine samples using this assay successfully identified metabolites from steroid treatments, demonstrating the effectiveness of these ELISA methods as initial screening tools for both new and known anabolic steroids.
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A method has been developed for the detection of modafinil and its major metabolite, modafinil acid, in equine urine by solid-phase extraction and positive ion electrospray ionisation liquid chromatography/mass spectrometry. The method has been applied to the analysis of equine urine samples obtained after the oral administration of modafinil. Modafinil acid was the major component in the urine, and was detected up to 4 days post-administration.

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A study of the equine phase II metabolism of the anabolic agent boldenone is reported. Boldenone sulfate, boldenone glucuronide and their C17-epimers were synthesised as reference standards in our lab and a method was developed for their detection in a horse urine matrix. Solid phase extraction was used to purify the analytes, which were then detected by ion trap LC/MS.

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The equine phase I and phase II metabolism of the synthetic anabolic steroid stanozolol was investigated following its administration by intramuscular injection to a thoroughbred gelding. The major phase I biotransformations were hydroxylation at C16 and one other site, while phase II metabolism in the form of sulfate and beta-glucuronide conjugation was extensive. An analytical procedure was developed for the detection of stanozolol and its metabolites in equine urine using solid phase extraction, acid solvolysis of phase II conjugates and analysis by positive ion electrospray ionization ion trap LC-MS.

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An investigation has been conducted into the metabolism and urinary excretion of orally administered piroxicam and tenoxicam in the horse. The major component detected in urine after the administration of piroxicam was 5'-hydroxypiroxicam, which was detectable up to 24 h post-administration. Unchanged piroxicam was present only as a minor component.

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The phase I and phase II metabolism of the anabolic steroid methandrostenolone was investigated following oral administration to a standardbred gelding. In the phase I study, metabolites were isolated from the urine by solid-phase extraction, deconjugated by acid catalysed methanolysis and converted to their O-methyloxime trimethylsilyl derivatives. GC-MS analysis indicated the major metabolic processes to be sequential reduction of the A-ring and hydroxylation at C6 and C16.

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After oral administration to a thoroughbred gelding, the anabolic steroid norethandrolone was converted into a complex mixture of oxygenated metabolites. These metabolites were extracted from the urine, deconjugated by methanolysis and converted to their O-methyloxime trimethylsilyl derivatives. Gas chromatographic/mass spectrometric analysis indicated the major metabolites to be 19-norpregnane-3,16,17-triols, 19-norpregnane-3,17,20-triols and 3,17-dihydroxy-19-norpregnan-21-oic acids.

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Risk factors for musculoskeletal injury in racing Thoroughbreds were investigated in a case-control study conducted at racetracks administered by the Australian Jockey Club. Univariable analysis of 137 cases from the official Veterinary Surgeon's reports and an equal number of randomly selected controls from the Australian Race Results identified field size, barrier position and class of race as being significantly associated with breakdown (P < 0.05).

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The combination of large doses of sodium bicarbonate and the potent narcotic, etorphine, has reportedly been given to racehorses in attempts to improve their performance and also to "mask" the presence of etorphine in urine samples. The increased urinary output and pH associated with sodium bicarbonate (approximately 500 g) administration may reduce the urinary concentration of etorphine, making it more difficult to detect. Our experiment was designed to examine the effects of this combination.

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We examined the effects of sodium bicarbonate in 6 Thoroughbred horses during submaximal and maximal treadmill exercise. Cardiorespiratory function was assessed together with the effect on exercise capacity by determining the run time to fatigue at maximal intensities. To discriminate between sodium bicarbonate's alkalinising effects and the fluid shifts that could result from the high osmotic load, we administered an equimolar solution of sodium chloride as a control.

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Dextromoramide (Palfium) was given by intravenous injection to a Thoroughbred horse at a dosage of 20 mg and urine was collected 2, 4, 6 and 8 h after drug administration. Enzymatic hydrolysis of the urine followed by solvent extraction gave a residue which was back-extracted into 0.1 M sulphuric acid.

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Five standardbred geldings were given 1 mg/kg bodyweight of frusemide by intramuscular injection to induce mild dehydration. After food and water deprivation overnight, the mean weight loss was 24.4 +/- 1.

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An abnormal mesocolic attachment which resulted in a stellate malformation of the left colon adjacent to the pelvic flexure was suspected to be the cause of intermittent episodes of colic in a horse. Resection and side-to-side anastomosis of the large colon at the level of the sternal and diaphragmatic flexures was performed and the horse made an uneventful recovery from surgery. Only minor serum biochemical changes were observed in the initial postoperative period.

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Circumcision (or reefing operation) was performed on an aged pony stallion to remove excessive granulation tissue involving the preputial integument following an injury and subsequent paraphimosis. Postoperative swelling of the penis and prepuce was reduced daily with gentle massage. Initially, an improvised suspensory was used to support the penis postoperatively.

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A 16 month old filly was presented with the complaint of a severe laceration to the right foreleg with resultant transection of the extensor carpi radialis. Normal principles of wound treatment were followed and a bandage and splint were used for support and immobilization. The return to partial function of the damaged extensor carpi radialis was evidenced by resolution of the wound and an improvement in the patient's gait four months after the time of injury.

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