Granulomatous Rhinitis in a Horse due to Mycobacterium intracellulare Infection.

Mycobacterial infections in horses are uncommon, but are caused most frequently by Mycobacterium bovis of the Mycobacterium tuberculosis complex or Mycobacterium avium of the M. avium complex. Disease caused by Mycobacterium intracellulare, the second most common species within the M. avium complex, has not been reported in horses to date. Mycobacteriosis in horses most often presents as enteric, pulmonary or, rarely, systemic disease. Here we report a case of M. intracellulare infection in a horse presenting as a granulomatous nasal mass.

Age-related effects on markers of inflammation and cartilage metabolism in response to an intra-articular lipopolysaccharide challenge in horses.

Eighteen Quarter Horses were used in a randomized complete design for a 28-d experiment to evaluate age-related effects on inflammation and cartilage turnover after induction of a single inflammatory insult using lipopolysaccharide (LPS). Horses were grouped by age as yearlings (3 males and 3 females), 2 to 3 yr olds (2/3 yr old; 2 males and 4 females), and skeletally mature 5 to 8 yr olds (mature; 2 males and 4 females). On d 0, all horses were individually housed and fed diets that met or exceeded requirements. On d 14, horses were challenged with an intra-articular injection of LPS. Radial carpal joints were randomly assigned to receive 0.5 ng LPS solution obtained from O55:B5 or 0.8 mL sterile lactated Ringer's solution as a contralateral control. Synovial fluid was collected prior to LPS injection at h 0 before injection and at 6, 12, 24, 168, and 336 h after injection. Samples were analyzed using commercial ELISA kits for PGE, collagenase cleavage neoepitope (C2C), and carboxypropeptide of type II collagen (CPII). Heart rate (HR), respiratory rate (RR), and rectal temperature (RT) were monitored over the initial 24 h and carpal circumference and surface temperature were also recorded, with additional measurements at 168 and 336 h. Data were analyzed using PROC MIXED of SAS. Values for RT, HR, and RR were within the normal range for each age group. Heart rate and RT were influenced by age ( < 0.01), whereas RR was unaffected ( ≤ 0.21). Joint circumference was not influenced by age of horse ( = 0.84), but circumference and surface temperature increased ( < 0.01) over time across all age groups. Synovial PGE concentrations tended ( = 0.09) to be influenced by age, with yearlings having lower ( = 0.03) concentrations than mature horses. Concentrations of synovial C2C were affected by age of horse, with yearlings and 2/3 yr olds having lower ( < 0.01) concentrations than mature horses. Similarly, synovial CPII was influenced by age, with yearlings and 2/3 yr olds having lower ( ≤ 0.02) concentrations than mature horses. Ratios of anabolic CPII to catabolic C2C varied by age, with mature and 2/3-yr-old horses having greater ( < 0.01) values compared with yearlings. These results indicate that inflammation and the corresponding cartilage turnover in response to LPS administration vary with age.

Influence of oral glucosamine supplementation in young horses challenged with intra-articular lipopolysaccharide.

Fourteen yearling Quarter horses (351 to 470 kg) were utilized in a randomized complete block design to evaluate potential of glucosamine hydrochloride (HCl) to mitigate intra-articular inflammation following a single inflammatory insult. Horses were blocked by BW, age, and sex, and randomly assigned to treatments for a 98-d experiment. Treatments consisted of a control diet (CON; = 7) fed 1% BW per d (as-fed) of concentrate only or a treatment diet ( = 7) of concentrate top dressed with 30 mg/kg BW glucosamine HCl (99.6% purity; GLU30) offered at 12 h intervals. Horses were maintained in individual stalls and offered approximately 1% BW per d of coastal bermudagrass hay (). Plasma and synovial fluid samples were obtained every 14 and 28 d, respectively, and stored at -20°C, before analysis of glucosamine via HPLC. On d 84, an intra-articular lipopolysaccharide (LPS) challenge was conducted on all horses to determine ability of dietary glucosamine HCl supplementation to mitigate joint inflammation and cartilage metabolism. Carpal joints were randomly selected to receive 1 of 2 intra-articular treatments and included sterile lactated Ringer's (control; Contra) only or 0.5 ng LPS solution (LPS) obtained from O55:B5 into the radial carpal joint. Synovial fluid was obtained at pre-injection h 0 and 6, 12, 24, 128, and 336 h post-injection, and was analyzed for prostaglandin E (PGE), carboxypeptide of type II collagen (CPII) and collagenase cleavage neopeptide (C2C) biomarkers by commercial ELISA kits. Data were analyzed using PROC MIXED procedure of SAS. Plasma and synovial glucosamine tended ( = 0.10 and = 0.06, respectively) to increase over time in response to GLU30 compared to CON. There was a treatment by time interaction ( ≤ 0.01), with GLU30 increasing plasma glucosamine concentrations at 28 and 42 d when compared to CON. A treatment by time interaction ( ≤ 0.01) was observed with GLU30 increasing synovial glucosamine levels at d 28 and 84 ( ≤ 0.01 and = 0.05, respectively). Intra-articular LPS increased ( ≤ 0.01) synovial PGE, C2C, and CPII levels. GLU30 decreased synovial PGE and C2C concentrations when compared to CON ( = 0.04 and = 0.05, respectively), while synovial levels of CPII increased ( ≤ 0.01) in GLU30 horses. These results indicate the potential for oral glucosamine HCl to mitigate intra-articular inflammation and influence cartilage turnover in a young horse model.

Influence of an intra-articular lipopolysaccharide challenge on markers of inflammation and cartilage metabolism in young horses.

Nineteen weanling Quarter Horses (225 to 380 kg) were used in a randomized complete block design to investigate the effects of intra-articular lipopolysaccharide (LPS) to induce acute joint inflammation in young horses. Horses were blocked by age, BW, and sex and were randomly assigned to 1 of 3 treatments for a 35-d experiment. Treatments included intra-articular injection of 0.25 ng (n = 7) or 0.50 ng (n = 6) of LPS obtained from Escherichia coli O55:B5 or sterile lactated Ringer's solution (n = 6; control) into the radial carpal joint. Synovial fluid was obtained at preinjection h 0 and 2, 6, 12, 24, 168, and 336 h postinjection and was analyzed for PGE2, carboxypeptide of type II collagen (CPII), and collagenase cleavage neopeptide (C2C) biomarkers via commercial ELISA kits. Rectal temperature (RT), heart rate (HR), respiratory rate (RR), and carpal circumference were recorded before each sample. Lameness scores on a 0 to 5 scale were conducted after arthrocentesis. Data were analyzed using PROC MIXED procedure of SAS. Linear and cubic effects were tested in the form of contrasts. Clinical assessment of HR, RR, and RT were not influenced by treatment (P ≤ 0.16). All horses exhibited increased lameness scores over time (P ≤ 0.01), and horses receiving LPS, regardless of dose, had greater recorded lameness scores at 12 and 24 h postinjection (P ≤ 0.05). Joint circumference increased (P ≤ 0.01) across treatments in response to repeated arthrocentesis. Mean synovial fluid PGE2 concentrations increased linearly with increasing levels of LPS administration (P ≤ 0.01). Additionally, regardless of treatment, PGE2 increased over time and peaked at 12 h postinjection (P ≤ 0.01) and remained elevated above baseline at 336 h postinduction. Synovial concentrations of anabolic CPII increased linearly (P ≤ 0.01) with increasing dosage of LPS and increased (P ≤ 0.01) over 24 h in all horses, beginning at 6 h and peaking at 24 h postinjection. Concentrations of C2C in synovial fluid were not influenced by treatment and decreased from 0 to 6 h and steadily increased to 24 h in all horses (P ≤ 0.01). These results indicate that intra-articular LPS induced intra-articular inflammation and collagen synthesis in young horses and that the response is dose dependent. The use of this model to induce predictable joint inflammation may provide insight to the efficacy of preventative strategies relating to joint disease in the young horse.

The development and evaluation of a mathematical nutrition model to predict digestible energy intake of broodmares based on body condition changes.

Mathematical nutrition models have been developed for beef and dairy cattle to estimate dietary energy intake needed to change BCS. Similar technology has not been used to improve nutrition and feeding strategies for horses. An accurate equine nutrition model may enhance feeding management and reduce the costs of unnecessary overfeeding and promote an optimal level of fatness to achieve reproductive efficiency. The objectives of this study were to develop and evaluate a mathematical nutrition model capable of accurately predicting dietary energy changes to alter BW, rump fat (RF) thickness, and overall body fat (BF), which is needed to maximize profitability and productivity of mares. Model structure was similar to a previously developed model for cattle, and literature data for Quarter Horse mares were used to parameterize the horse model in predicting DE requirement associated with BCS changes. Evaluation of the horse model was performed using an independent dataset comprising 20 nonlactating Quarter Horse mares. Pretrial BCS was used to assign mares to 1 of 4 treatment groups and fed to alter BCS by 1 unit as follows: from 4 to 5 (Group 1), 5 to 4 (Group 2), 6 to 7 (Group 3), and 7 to 6 (Group 4). The BCS, RF thickness, and BW were measured for each mare before the commencement of the feeding trial and once per week thereafter for the duration of a 30-d feeding trial. Initial and target BCS, percent BF, and BW data were collected from each mare and inputted into the model. Mares were individually fed according to the DE suggestions proposed by the model to achieve the targeted BCS change within 30 d. The coefficient of determination of observed and model-predicted values (model precision) was 0.907 (P < 0.001) for BCS, 0.607 (P < 0.001) for percent BF, and 0.94 (P < 0.001) for BW. The BCS was highly correlated to percent BF (r = 0.808; P = 0.01). We concluded the reparameterized model was reliable to predict changes in BW and BCS, but more work is needed to improve the predictions of initial and final body composition.

Thermoregulation of the testicle in response to exercise and subsequent effects on semen characteristics of stallions.

Stallions (n = 8) were implanted with a thermal sensory device in the muscle of the neck and the subcutaneous tissue of the scrotum and then assigned to either a nonexercise (Non-EX; n = 4) or exercise (EX; n = 4) group. A motorized equine exerciser was used to work EX stallions 30 min/d for 4 d/wk during a 12-wk period from July through October 2010. Temperatures (subcutaneous scrotal, intramuscular neck, and rectal) were recorded at 0, 22, and 30 min after the start of exercise, as well as 60 and 120 min post-exercise. Hourly ambient temperature and relative humidity data were also obtained. Semen was collected at 0, 4, 8, and 12 wk and analyzed for volume, sperm concentration, total sperm numbers, percentages of total and progressively motile sperm, sperm morphologic characteristics, and sperm DNA quality. No effect (P > 0.05) of exercise was observed on any of the measured semen variables. Implantation of thermal sensory devices had no demonstrable acute or chronic effects on the scrotal or neck tissue, indicating that the thermal sensory devices are a safe and effective way to measure subcutaneous scrotal and neck temperatures. At 22 and 30 min of exercise, rectal and neck temperatures increased (P < 0.0001) approximately 1.9 and 2.4°C, respectively, and scrotal temperatures simultaneously increased, although not significantly (P = 0.33), approximately 0.8°C. Correlations existed between scrotal, neck, rectal, and ambient temperatures, with the correlation between scrotal and rectal temperatures being greatest (r(s) = 0.76; P < 0.0001). Although moderate exercise for a short duration in extreme heat and humidity did significantly increase core body temperatures in stallions, scrotal temperatures did not significantly increase, and sperm parameters were unaffected.

Pharmacokinetics of an orally administered methylcellulose formulation of gallium maltolate in neonatal foals.

Gallium is a trivalent semi-metal with anti-microbial effects because of its incorporation into crucial iron-dependent reproductive enzyme systems. Gallium maltolate (GaM) provides significant gallium bioavailability to people and mice following oral administration and to neonatal foals following intragastric administration. To study the prophylactic and therapeutic effects of GaM against Rhodococcus equi pneumonia in foals, we developed a methylcellulose formulation of GaM (GaM-MCF) for oral administration to neonatal foals. Normal neonatal foals were studied. Six foals received 20 mg/kg and another six foals received 40 mg/kg of GaM-MCF orally. Serial serum samples were collected and serum gallium concentrations were determined using inductively coupled plasma mass spectroscopy. Gallium was rapidly absorbed (T(max) of 4 h), and a mean C(max) of 0.90 or 1.8 microg/mL was achieved in foals receiving 20 or 40 mg/kg respectively. Marked variability existed in C(max) among foals: only half of the foals receiving 20 mg/kg attained serum concentrations of >0.7 microg/mL, a level suggested to be therapeutic against R. equi by previous studies. Mean elimination half-life was 32.8 or 32.4 h for foals receiving 20 or 40 mg/kg respectively. The results of this study suggest that at least 30 mg/kg orally every 24 h should be considered in future pharmacodynamic and efficacy studies.

Conservative management of 17 horses with nonarticular fractures of the tibial tuberosity.

REASONS FOR PERFORMING STUDY: Fractures of the tibial tuberosity (FTT) are caused by direct trauma, and are the second most commonly reported injury in event horses with stifle trauma. Conservative management of horses with FTT has been advocated, but results and prognosis for this method of therapy are unknown. OBJECTIVES: To report and review the findings of a retrospective study of 17 horses admitted to a veterinary teaching hospital from 1986-2001 with nonarticular FTT that received conservative management. METHODS: Subject details, aetiology of the accident, limb affected, degree of lameness at time of admission, size and degree of displacement of the fracture fragment, complications such as comminution of the fracture fragment or damage to soft tissue structures within the affected stifle, and treatment recommendations were obtained from medical records. Owners and trainers were contacted regarding the horse's return to athletic use. The follow-up period consisted of 11-154 months. RESULTS: Two horses were reportedly sound, but unable to return to competition for unrelated reasons. Of the horses that completed the rehabilitation period, 12/15 (80%) returned to athletic use at the same level as before the injury. Three horses were diagnosed with damage to soft tissue supporting structures of the affected stifle and could not return to their former level of competition. CONCLUSIONS: Concurrent soft tissue damage, diagnosed at the time of the initial injury, was statistically significant in precluding horses from returning to athletic careers. All other variables were found to have no effect upon outcome. POTENTIAL CLINICAL RELEVANCE: This retrospective study suggests that the conservative management of nonarticular FTT is a viable treatment modality in managing athletic equine patients presenting with these fractures.

Leader peptide efficiency correlates with signal recognition particle dependence in Saccharomyces cerevisiae.

Secretion of bovine pancreatic trypsin inhibitor (BPTI) in Saccharomyces cerevisiae was examined with four different leader peptides: the invertase signal peptide, the mfalpha1 signal peptide, a synthetic signal peptide, and a synthetic pre pro leader. BPTI secretion from a low-copy CEN plasmid varies from 1.8 to 10.4 microgram/mL among these constructs. Secretion titers correlate with dependence on signal recognition particle (SRP), with greatest secretion from the most SRP-dependent construct. Examination of co- vs post-translational translocation pathways and overall translocation efficiency by ubiquitin translocation assay (UTA) does not provide insight into the variation in BPTI secretion efficiency, perhaps due to alteration in translocation kinetics from the additional polypeptide fusion required by the assay. BPTI translocation efficiency (as measured by UTA) is found to drop markedly upon depletion of Srp54p, prior to any observable growth defect. Subsequent to stress response induction and the onset of slow growth (15-h doubling time), BPTI translocation efficiency recovers to the level observed prior to SRP depletion.

The stress response to loss of signal recognition particle function in Saccharomyces cerevisiae.

It has been shown previously that growth and endoplasmic reticulum (ER) translocation defects occur in response to depletion of the 54-kDa subunit of signal recognition particle (SRP54) in Saccharomyces cerevisiae (Hann, B. B., and Walter, P. (1991) Cell 67, 131-144). We report here that cells depleted of SRP54p undergo a general stress response, the onset of which is observed almost two-cell doublings after SRP54 protein levels fall below the limits of detection. The stress response to SRP54p depletion occurs in two distinct phases, unlike the response to other stressors such as heat shock. In the initial phase, the cytoplasmic Hsp70 levels are drastically increased coincident with an abrupt slowing of growth and accumulation of untranslocated species of the ER-resident chaperone BiP. During this first response, levels of the yeast DnaJ homolog Ydj1p are also increased. In the second phase, which is detected 5 h later, levels of the cytoplasmic heat shock proteins Hsp82 and Hsp104 are increased. BiP is also induced during this second phase, while the ER levels of the resident foldase protein disulfide isomerase are significantly reduced. Since only those cytoplasmic stress proteins which have been shown to participate in membrane translocation are induced in the first phase, these findings indicate the presence of a stress response specific to accumulation of secretory protein precursors in the cytoplasm.

Laboratory caging preferences in golden hamsters (Mesocricetus auratus).

Physical aspects of the laboratory environment, such as type of cage or bedding, are often ignored by investigators but may be quite important for the animals. We examined whether golden hamsters preferred living in wire mesh floored, stainless steel cages or solid floored, plastic cages with corn-cob litter. Forty hamsters of 2 ages were housed in wire or solid floored cages for 3 weeks. Caging preference was then tested using a choice apparatus in which hamsters could move freely between the 2 cages for 6 days. Scan data were collected on cage occupation and behaviour. Results showed that most hamsters preferred the solid floored cage with litter, but prolonged experience on wire led to a wire floored cage preference in 40% of these animals. Also, wire-housed hamsters showed higher levels of hoarding and lower levels of gnawing behaviour during testing, and spent significantly different amounts of time from litter-housed hamsters performing sleeping, exploring, grooming, gnawing, eating, and hoarding behaviours while on solid floored cages with litter. This study shows that previous housing condition can affect cage preferences and behaviour and supports the assertion that husbandry practices can be better evaluated by asking laboratory animals, rather than only humans, how their living conditions are perceived.