Perivascular wall tumour presenting as pastern mass in a Standardbred gelding.

A 2-year-old Standardbred gelding was referred for a mass on the palmaromedial right front pastern which was accompanied by progressively worsening lameness. The mass was firm to palpation and covered by normal skin. Ultrasonographically, a smooth encapsulated mass was present, medial to the flexor tendons and palmar to the neurovascular bundle. Because of a poor prognosis for future athletic performance without surgical or chemotherapeutic intervention and economic constraints preventing further diagnostics and treatment, the horse was euthanised. Post-mortem magnetic resonance imaging, histopathology and immunohistochemistry revealed the mass to be a perivascular wall tumour, the first record of such a neoplasia in the horse.

Ingestion of dug well water from an area with high prevalence of chronic kidney disease of unknown etiology (CKDu) and development of kidney and liver lesions in rats

Introduction: Chronic kidney disease of unknown aetiology (CKDu) is prevalent in the North Central Province (NCP) of Sri Lanka and ingestion of dug well water is considered a potential causative factor. Three CKDu prevalent villages were selected from the NCP based on the number of CKDu patients in the locality. Methods: Forty Wistar rats were divided into four groups with 10 rats each. Group No 1, 2 and 3 were given water from selected dug wells. Control group was given tap water from Colombo. Water samples were analysed for fluoride, iron, arsenic, cadmium and calcium. Histopathological examination of liver and kidney tissues were performed. Results: Significant reduction of glomerular filtration rate (GFR) was observed in two test groups compared to the control group (p0.05). In one group hepatocellular carcinoma with elevated serum liver enzymes was observed whilst hepatitis was observed in another test group (p<0.05). But mixed lesions were common in all affected rats. Significantly high renal tubular lesion index was observed in all three experimental groups (p<0.05) and high glomerular lesion index (p=0.017) was observed in one test group. Cadmium, arsenic and iron contents were below detectable levels in the NCP water sources and tap water from Colombo. Conclusions: Different wells may have different concentrations of environmental toxins and depending on the severity of the toxin contents GFR and grade and type of liver and kidney lesions may vary. High fluoride and other undetected toxins in shallow dug wells may be the causative factors for renal and liver lesions in these Wistar rats.

Effect of Manuka honey gel on the transforming growth factor ß1 and ß3 concentrations, bacterial counts and histomorphology of contaminated full-thickness skin wounds in equine distal limbs.

OBJECTIVE: To investigate the effect of 66% Manuka honey gel on the concentrations of transforming growth factor (TGF)-ß1 and TGF-ß3, bacterial counts and histomorphology during healing of contaminated equine distal limb wounds. METHODS: In this experimental study of 10 Standardbred horses, five full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus and six similar wounds were created on the contralateral metacarpus. Wounds were assigned to three groups: non-contaminated control wounds; contaminated control wounds; contaminated wounds treated daily with 1 mL Manuka honey gel topically for 10 days. For the contaminated wounds, faeces were applied for 24 h after wound creation. In five horses wounds were bandaged and in the other five horses wounds were left without a bandage. Biopsies were taken on days 1, 2, 7 and 10 after wounding to evaluate the effects of Manuka honey gel, wound contamination and bandaging on TGF-ß1 and TGF-ß3 concentrations, aerobic and anaerobic bacterial counts, and histomorphology. RESULTS: Manuka honey gel had no significant effect on TGF-ß1 and TGF-ß3 concentrations or wound bacterial counts. Manuka honey gel decreased wound inflammation (days 7, 10), increased angiogenesis (days 2, 7, 10), increased fibrosis and collagen organisation (day 7) and increased epithelial hyperplasia (days 7, 10). CONCLUSIONS: Treatment with Manuka honey gel resulted in a more organised granulation tissue bed early in wound repair, which may contribute to enhanced healing of equine distal limb wounds.

Effect of activated protein C in second intention healing of equine distal limb wounds: a preliminary study.

OBJECTIVE: To investigate the effect of activated protein C (APC) on second intention healing of distal limb wounds in horses. METHODS: In this experimental study of eight Standardbred geldings, six full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus (biopsy limb) and five similar wounds were created on the contralateral metacarpus (photographed limb). Three wounds on the biopsy limb were treated topically with 190 µg APC on days 1, 3, 6 and 9, while the remaining three wounds were untreated (control). One treated and one control wound were biopsied on days 4, 7 and 11 for histopathology. Wounds on the photographed limb were treated with either 66% Manuka honey gel, a commercial antibiotic ointment (bacitracin-neomycin-polymixin B ointment; BNP) or petrolatum daily throughout healing, treated on days 1,3,6 and 9 with 190 µg APC or left untreated. These wounds were digitally photographed and the wound area measured on day 1, then weekly until day 49. Overall time to healing was recorded. RESULTS: There was no effect of APC on wound size, the rate of healing or the overall time to heal. However, compared with control wounds, histological scoring demonstrated enhanced epithelialisation (day 4) and angiogenesis (day 11). Wound healing variables for wounds treated with APC, Manuka honey gel and control wounds were not different and the variables for wounds treated with BNP and petrolatum demonstrated delayed healing. CONCLUSION: The improvements in histological scores in APC-treated wounds suggest further study into the effect of APC on second intention wound healing in horses is warranted.

Effects of intra-articular sodium pentosan polysulfate and glucosamine on the cytology, total protein concentration and viscosity of synovial fluid in horses.

OBJECTIVE: Evaluate synovial fluid cytology, total protein concentration and viscosity after intra-articular administration of combined pentosan polysulfate and glucosamine in horses. DESIGN: Ten adult Standardbred horses had each carpal joint (n = 20) randomly assigned to one of two treatments: control (5 mL saline) or treated (pentosan polysulfate and glucosamine). All horses received an intra-articular injection every 7 days for 3 weeks and synovial fluid samples were collected on days 1 (baseline), 2, 3, 7, 8, 9, 14, 15, 16 and 21. Synovial fluid variables measured included total protein concentration, total nucleated cell count, red blood cell count, the neutrophil, lymphocyte, mononuclear cell and eosinophil percentages, and viscosity. RESULTS: Following injection, the total nucleated cell count increased in the synovial fluid samples from both groups. Values were significantly higher in treated joints on days 2, 3, 15 and 16. Red blood cell counts were low and no differences were seen between treated and control joints. Total protein concentrations and neutrophil percentages increased in both groups after injection, but decreased towards normal ranges within 7 days. Total protein concentration was significantly higher in treated joints on days 1, 3, 8, 9 and 15. Percentages of neutrophils were higher in treated joints on day 2, but significantly lower on days 8 and 15. Viscosity was significantly higher in treated joints on day 2 only. CONCLUSIONS: Intra-articular administration of combined pentosan polysulfate and glucosamine causes a mild inflammatory synovitis that is not substantially different to that elicited by injection of a similar volume of saline and so we conclude that these drugs are safe to use in the horse.

Effects of collecting serial tracheal aspirate and bronchoalveolar lavage samples on the cytological findings of subsequent fluid samples in healthy Standardbred horses.

OBJECTIVE: To evaluate the effect of collecting serial tracheal aspirate (TA) and bronchoalveolar lavage (BAL) samples on the cytological findings of subsequent fluid samples obtained from horses without clinical signs of respiratory disease. STUDY DESIGN: Experimental. STUDY POPULATION: Six healthy Standardbred horses. METHODS: Endoscopically-guided TA samples, and BAL samples collected using the blind field technique were obtained from the six horses on days 1, 2, 3, 4, 5, 12, and 17. On day 17, horses were sampled three times: at baseline and at 2.5 h and 4 h apart. The differential cytology of the fluid samples collected at each time point was expressed as percentages and compared statistically. RESULTS: There was a significant increase in neutrophil percentage in the TA samples taken at day 17 (at 2.5 h but not at 4 h apart). There was no significant change in the neutrophil percentages in the TA samples when repeated samples were taken ≥ 24 h apart. There was no significant change in the neutrophil percentages in the BAL fluid at any collection point. There were inconsistent changes in the percentages of lymphocytes and macrophages in the BAL fluid over time, but these remained within normal reference ranges and were considered clinically insignificant. CONCLUSIONS: Serial TA and BAL samples can be taken at 24 h intervals without affecting the cytological findings of subsequent fluid samples collected using the techniques described.

Surgical resection of a dysgerminoma in a mare.

A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematology and serum biochemistry results were within normal limits. The mare was initially treated conservatively with antibiotics, but the mass continued to increase in size, so it was surgically excised. The mass involved the left ovary. The mare showed transient abdominal pain after surgery, but developed no other complications and was in foal 7 months later. On histology, the mass was diagnosed as a dysgerminoma, a rare ovarian tumour of germ cell origin.

Development of a clinical syndrome resembling haemorrhagic septicaemia in the buffalo following intravenous inoculation of Pasteurella multocida serotype B:2 endotoxin and the role of tumour necrosis factor-alpha.

Clinical changes and acute phase responses, including tumour necrosis factor-alpha (tnfalpha), in six buffalo calves were examined following intravenous inoculation of a bolus of endotoxin (1 microg kg(-1) bodyweight in 10 ml of phosphate-buffered saline [ pbs ]) extracted from Pasteurella multocida serotype B:2, the bacterium responsible for haemorrhagic septicaemia (hs) in Asia. Endotoxin injection caused a rapid onset of clinical signs characterised by dullness, sternal recumbency, elevated rectal temperatures, excessive salivation and dyspnoea that lasted for up to 12 hours post-inoculation (p.i.). Serum concentrations of tnfalpha rose within 1 hour p.i. to reach peak values ranging between 8 and 140 ng ml(-1) at 1-2 hours p.i. and then declined rapidly to baseline levels 3-5 hours p.i. Endotoxin injection induced other acute phase changes, including a rapid leucopenia and reductions in the serum concentrations of iron and zinc and a delayed but prolonged increase in haptoglobin from 12 hours p.i. that reached a plateau from about 60 hours p.i. Three control calves injected with 10 ml pbs showed no clinical or blood compositional changes. By reproducing key signs of hs the work confirms a pivotal role of endotoxin in the pathogenesis of hs and emphasises the exquisite sensitivity of the buffalo to P multocida endotoxin.

Role of endotoxin in the pathogenesis of haemorrhagic septicaemia in the buffalo.

The pathogenesis of haemorrhagic septicaemia in buffalo infected with Pasteurella multocida is poorly understood. However, the characteristic of sudden onset leading to the rapid death of infected animals is similar to that seen in other clinical conditions known to involve endotoxic shock. The objectives of the work were to assess the contribution of endotoxaemia to the disease's pathogenesis and to characterize the pathophysiological reaction, including the acute phase response, of buffalo to experimental infection with P. multocida serotype B:2, the bacterium responsible for the disease in Asia. After intranasal infection of eight buffaloes with a culture of a field isolate of P. multocida serotype B:2, three animals succumbed to the disease at 26-30 h post-infection (p.i.) and five survived. Rectal temperatures of infected animals rose to a peak at about 10 h p.i. and surviving animals showed a second peak in rectal temperature at 36 h p.i. Endotoxin was present only in serum of non-surviving animals 3-5 h before death or killing during which time concentrations increased rapidly, correlating with the development of overt clinical signs and reductions in rectal temperature, concentrations of white blood cells, serum thyroxine, iron, copper and zinc, an increase in serum haptoglobin and cortisol and the detection of a low-grade bacteraemia. A strong acute phase response was maintained in surviving animals with a progressive rise in serum haptoglobin over 96 h p.ia slow rise in the serum copper concentration from 24 h p.i. and an increase, from about 65 h p.iin serum alpha(1)-acid glycoprotein. The findings demonstrate that a progressive endotoxaemia and associated sequelae correlates with the development of overt haemorrhagic septicaemia disease and sudden death in buffalo.

Characterisation of bovine lipopolysaccharide binding protein and the in vivo acute phase response to Pasteurella haemolytica Type A.

Lipopolysaccharide binding protein (LBP) is a liver-derived acute phase protein which is implicated in modulating the host responses to lipopolysaccharide (LPS) from Gram-negative bacteria. LBP interacts with circulatory LPS to form complexes which bind to the CD14 receptor or cells of the monocytic lineage and neutrophils resulting in their activation. This causes the release of mediators and cytokines which are responsible for initiating the acute phase response. LBP-like activity has now been identified in bovine serum and in this study LBP has been purified from acute phase bovine serum using ion exchange chromatography. On sodium dodecyl sulphate polyacrylamide electrophoresis, bovine LBP demonstrated a single band with a molecular mass of 58 kDa. Bovine LBP enhanced the binding of LPS to human monocytes while enzymatic removal of the CD14 receptor abrogated this interaction. Furthermore, bovine LBP increased the sensitivity of monocytes to LPS by at least 100-fold. Depletion of LBP by means of antibodies to bovine LBP inhibited the serum mediated LPS binding to monocytes. Antibodies to rabbit LBP or recombinant human LBP did not cross-react with bovine LBP. Studies on the kinetics of LBP activity in calves during the acute phase response demonstrated a four-fold increase in the serum concentration 36 h after a single intratracheal inoculation of Pasteurella haemolytica A1. The findings of this study indicate that cattle possess a LPS detection mechanism comparable to that described in man and experimental animals in which LBP forms complexes in serum with circulatory LPS enhancing the signal to the immune system to mount a host response. The isolation of LBP will allow further investigations into LBP-mediated responses to LPS in cattle.