Progression of osteoarthritis following TPLO surgery: a prospective radiographic study of 40 dogs.

The aim of this prospective study was to assess the progression of osteoarthritis following tibial plateau levelling osteotomy (TPLO) surgery. Osteoarthritis was monitored radiographically by means of an osteophyte scale on entry to the study, and at six weeks and six months following surgical intervention. Forty dogs were recruited to the study. At each visit, animals were assessed clinically, radiographically, by force platform analysis and by synovial fluid sampling. The radiographic data is the subject of this report. A significant increase in mean osteophyte score was noted between the entry and six-month examination time point. This increase in the mean osteophyte score was due to the increased score recorded in 16 dogs. However, in the majority of dogs, there was no progression of osteophytosis during the course of this study.

Syringohydromyelia in Cavalier King Charles spaniels.

Syringohydromyelia secondary to foramen magnum overcrowding is described in seven Cavalier King Charles spaniels. Clinical signs were consistent with a central spinal cord lesion. The most common signs were persistent scratching at the shoulder region with apparent neck, thoracic limb, or ear pain and thoracic limb lower motor neuron deficits. The diagnosis was made by magnetic resonance imaging. The syringohydromyelia is postulated to be a consequence of an occipital bone malformation resulting in a small caudal fossa and cerebellar herniation. Clinical signs improved but did not completely resolve when the dogs received treatment with corticosteroids or nonsteroidal anti-inflammatory drugs.

Hydromyelia in the dog.

Hydromyelia is a dilation of the spinal cord central canal. In man this may be due to congenital malformations such as Dandy-Walker syndrome and Chiari malformations or may be acquired as result of infection, trauma or neoplasia. In dogs hydromyelia may be accidentally diagnosed during routine cisterna magna myelography. Hydromyelia, and its possible etiology, may be confirmed by means of computed tomography or magnetic resonance imaging. Three dogs with hydromyelia due to differing etiologies are described.

Vaginourethroplasty for treatment of urethral obstruction in the bitch.

Vaginourethroplasty was performed in six bitches with infiltrative, obstructive urethral disease. The initial clinical signs included dysuria, hematuria, pollakiuria, and stranguria. Diagnosis was based on the clinical signs, plain radiography and contrast vagino-urethrogram examination, and urethral biopsy. Five dogs were diagnosed as having urethral neoplasia; the sixth dog had granulomatous urethritis. In all six dogs, up to 50% of the urethra and the urethral tubercle were resected to ensure adequate surgical margins. One dog was euthanatized 4 months after surgery for recurrence of a transitional cell carcinoma at the surgical site. Long-term resolution of the problem (minimum of 12 months) was achieved in the other five dogs. The frequency of serious complications, including urinary incontinence and ascending lower urinary tract infections, was low.

Treatment of intrasynovial infection with gentamicin-impregnated polymethylmethacrylate beads.

Gentamicin-impregnated polymethylmethacrylate beads were used in the treatment of infective synovitis in 12 horses and 10 cattle. They had either proved refractory to standard treatments (lavage, debridement, joint drainage and systemic antibiotics) or had evidence of osteomyelitis adjacent to a synovial cavity. All the animals were severely lame. All the cattle and six of the horses had radiological evidence of osteomyelitis in communication with a synovial cavity. The beads were placed intrasynovially under general anaesthesia and left in place for 14 days. One horse and one calf were euthanased owing to continued infective arthritis. The infection was eliminated from the other 20 cases and six of the horses returned to full athletic use. Eight of nine calves with E-type infective arthritis and osteomyelitis returned to their intended food production or breeding programmes.

Normal intestinal motility.

Perhaps because of the inherent difficulty in using horses as experimental animals, only a relatively small amount of data is as yet available regarding normal equine gut motility. However, it is clear that the horse is fundamentally similar to other mammalian species studied. The neural and humoral control of gut activity requires much exploration; it is likely that, in the horse, some of this information will be derived during the investigation of the effects of various substances that might have clinical relevance. This is alluded to in the chapter that follows (The Effects of Pharmacological Agents on Gastrointestinal Motility). The clinical applications are likely to remain limited, though some light may be shed upon the derivation of certain disorders.

Reactions of reducing radicals with ribonuclease.

Radiation-induced reactions of hydrated electrons, formate- and ethanol radicals with ribonuclease were studied by pulse radiolysis and by electrophoresis. Initially formate radicals react rapidly and very specifically with the disulphide bonds of ribonuclease. This reaction leads to aggregation by intermolecular S-S-interchange, the process being more effective at pH 4, since formation and decay of S-S-.-radical anions increases with decreasing pH. With high doses additional unreducible aggregates are formed. Radical formation at the positively charged histidine residues seems to be involved. Hydrated electrons do not react as selectively as the formate radicals, but with several sites in native ribonuclease. Thus with low doses unreducible aggregates are formed. Electrophoresis shows that reaction of the electrons causes fragmentation of the peptide chain, when OH-radicals are scavenged. Very weak transient spectra and very little degradation result on reaction of ethanol radicals with ribonuclease.

Effect of experimental vascular occlusion on small intestinal motility in ponies.

Small intestinal ischaemia is a cause of pain in man and horses. Occlusion of the vascular supply to Thiry loops in experimental ponies caused severe discomfort and loss of motility within a few minutes but these effects could not be reproduced by a similar procedure in intact gut preparations. However, embolisation of the mural vascular network produced ischaemia of the small intestine of anaesthetised ponies which led to a cessation of motility in the affected segments, though unaffected segments became hypermotile with a characteristic motility pattern. These results suggest the need for reappraisal of the classical theory of parasite-induced damage to the cranial mesenteric artery as the cause of ischaemic bowel disease.

Effect of spasmolytic analgesic drugs on the motility patterns of the equine small intestine.

The effect of acepromazine, Buscopan (Crown Chemicals), pethidine and methadone was evaluated in ponies prepared with Thiry-Vella (T-V) loops. Motility was assessed by electrophysiological means (bipolar electrodes and strain gauge transducers) and by the passage through the T-V loop of a fluid test meal. Results were obtained from 26 experiments in three ponies and compared with six control experiments, in which saline had been administered to the same ponies. Each pony acted as its own control in each experiment and pre and post treatment values for slow wave frequency, spiking activity, delivery rate and flow rate were compared. Acepromazine reduced electrical activity, but increased volume transport. Buscopan produced little change, while pethidine and methadone both decreased electrical activity, but increased volume transit. These effects may be due to a decrease in tone with resulting increase in luminal volume of the intestine.