Lawsonia intracellularis proliferative enteropathy in a weanling foal in Australia.

A 6-month-old Quarter Horse weanling filly was presented with lethargy, weight loss, inappetance, mild diarrhoea, marked ventral oedema and severe panhypoproteinaemia. Serum antibody titres for Lawsonia intracellularis were very high but PCR to detect faecal shedding of the organism was negative. Proliferative enteropathy due to L. intracellularis infection was diagnosed. After treatment for 4 weeks with oral erythromycin and rifampicin the filly made a complete recovery.

Papillary ductal adenocarcinoma in the mammary glands of two horses.

Mammary gland neoplasms in horses are uncommon and may initially be confused with mastitis. Masses from the mammary glands of two horses with chronic discharges were examined by cytology and histopathology. Both masses were diagnosed as papillary ductal adenocarcinomas with extensive intraductal and intralobular involvement and only focal infiltration of the adjacent stroma. Complementary immunohistochemical studies were made of both fresh and formalin-fixed tumour tissue, and attempts were made to assess the steroid receptor status of fresh tissue biochemically to assess the possibility of hormonal treatment as an adjunct to surgery. The results of these tests for oestrogen and progesterone receptors were negative.

Retropharyngeal lymph node infection in horses: 46 cases (1977-1992).

A retrospective study of 46 horses with retropharyngeal lymph node (RPLN) infection presented to the Rural Veterinary Centre between 1977 and 1992 was undertaken. Horses aged less than one year were most commonly represented (46%). Thirty-nine percent of cases had been exposed to horses with confirmed or suspected strangles (Streptococcus equi subsp equi infection) within the previous 8 weeks. Most frequent signs were unilateral or bilateral swelling of the throat region (65%), respiratory stertor/dyspnoea (35%), purulent nasal discharge (20%), inappetence and signs of depression (15%), and dysphagia (9%). All horses had a soft tissue density in the retropharyngeal region on radiographs. Rhinopharyngoscopy, ultrasonography, haematology as well as cytological and microbial analysis of material aspirated from the soft tissue swelling facilitated diagnosis in some horses. Fifteen horses (33%) were treated with procaine penicillin intramuscularly for 4 to 7 days followed by oral trimethoprim-sulphadimidine for 7 to 14 days. Non-steroidal anti-inflammatory drugs were administered to 6 horses. Four required tracheostomy for severe respiratory distress. The 15 horses treated medically responded to treatment and were discharged from hospital. Three horses (6%) with mild signs received no treatment and recovered uneventfully. Twenty-eight horses (61%) underwent general anaesthesia and surgical drainage of a RPLN abscess. Nineteen received procaine penicillin G for 4 to 7 days. Four of the nine horses that did not receive antibiotic treatment after surgery required further surgical drainage 10 days to 7 weeks after the initial surgery. Limited follow-up information was available for 37 horses.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of equine sarcoids: 1975-93.

Treatment options for equine sarcoids are briefly reviewed and the results of a retrospective study of 63 cases of equine sarcoid (66 lesions) treated by clinicians from the Rural Veterinary Centre, Camden, Australia from 1975 to 1993 presented. Five different treatments were employed in the management of these 66 lesions, including surgical excision alone or in combination with cryotherapy, radiotherapy, immunotherapy and tumour transfer to a subcutaneous site on the neck. The majority of cases were treated with surgical excision alone (18/66), excision followed by cryotherapy (31/66) and immunotherapy (16/66), with success rates of 28%, 42% and 81% respectively. Success was defined as no sign of recurrence of the lesion at the time of follow-up, at least 6 months later.

Peritonitis associated with Actinobacillus equuli in horses: 15 cases (1982-1992).

Peritonitis attributable to Actinobacillus equuli was diagnosed in 15 horses examined at the veterinary center between 1982 and 1992. In 13 horses, historical findings included acute onset of mild to severe signs of abdominal pain, lethargy, and inappetence. Two other horses had a history of weight loss for 3 to 6 weeks prior to examination. Diagnosis was based on the physical signs and laboratory findings, including results of peritoneal fluid analysis (gross characteristics, total protein, total and differential nucleated cell counts, and morphologic findings) and culture of A equuli. Actinobacillus equuli was consistently susceptible in vitro to penicillin, trimethoprim/sulfadiazine, and aminoglycosides. All horses in the study had marked clinical improvement within 24 to 48 hours of commencing antibiotic and supportive treatment. Antibiotic treatment was continued for variable periods, depending on the horse, but ranged from 5 to 21 days. In 11 horses for which follow-up information was available, long-term response to treatment was excellent, with horses returning to original activity.

HPLC analysis of an amino bisphosphonate in pharmaceutical formulations using postcolumn derivatization and fluorescence detection.

Monosodium 4-amino-1-hydroxybutane-1, 1-diphosphonic acid (MK-217) is a bone resorption inhibitor implicated in the treatment of malignant hypercalcemia. This compound is very water soluble and has five ionizable groups with pKa values over the entire pH range. As a result, it is difficult to maintain a single species in solution for chromatographic separation. Since there is no chromophore in the molecular structure, UV detection is ineffective. The compound and its potential degradation products are separated by ion-pair chromatography using 0.01 M cetyltrimethylammonium bromide as the ion-pairing agent and a polymeric stationary phase. Detection is by fluorescence detection after postcolumn derivatization of the primary amine with ophthalaldehyde and mercaptoethanol (OPA-MERC). Optimization of the chromatographic separation and the postcolumn reaction has been carried out, and the method has been applied to the analysis of MK-217 in intravenous solutions and tablet formulations.

Studies on the optimal temperature of flotation tanks in the management of skeletal injuries in the horse.

In order to determine optimum tank temperature, nine horses were allocated randomly to three groups and placed in a flotation tank at temperatures of 28 degrees C, 32 degrees C and 36 degrees C. Their progress was monitored by subjective and objective clinical measurements and a variety of laboratory parameters. A 'reacclimatisation crisis' following removal from the tank was observed in most horses after immersion for 21 days and it was concluded that a tank temperature of 36 degrees C provided maximum patient comfort and minimum homoeostatic disturbance.

Pulmonary changes associated with flotation techniques in the treatment of skeletal injuries in the horse.

Six adult horses with normal blood gas values, normal thoracic radiographs and free from overt signs of respiratory disease were confined in flotation tanks for periods from one to seven weeks. With one exception, they all coughed, had a variable amount of nasal discharge and, at autopsy, showed cranio-ventral alterations to their lungs which were characterised by patchy irregular areas of absorption atelectasis with or without an inflammatory reaction and an accompanying alveolar emphysema.