A review of methods for assessment of the rate of gastric emptying in the dog and cat: 1898-2002

Gastric emptying is the process by which food is delivered to the small intestine at a rate and in a form that optimizes intestinal absorption of nutrients. The rate of gastric emptying is subject to alteration by physiological, pharmacological, and pathological conditions. Gastric emptying of solids is of greater clinical significance because disordered gastric emptying rarely is detectable in the liquid phase. Imaging techniques have the disadvantage of requiring restraint of the animal and access to expensive equipment. Radiographic methods require administration of test meals that are not similar to food. Scintigraphy is the gold standard method for assessment of gastric emptying but requires administration of a radioisotope. Magnetic resonance imaging has not yet been applied for assessment of gastric emptying in small animals. Ultrasonography is a potentially useful, but subjective, method for assessment of gastric emptying in dogs. Gastric tracer methods require insertion of gastric or intestinal cannulae and are rarely applied outside of the research laboratory. The paracetamol absorption test has been applied for assessment of liquid phase gastric emptying in the dog, but requires IV cannulation. The gastric emptying breath test is a noninvasive method for assessment of gastric emptying that has been applied in dogs and cats. This method can be carried out away from the veterinary hospital, but the effects of physiological and pathological abnormalities on the test are not known. Advances in technology will facilitate the development of reliable methods for assessment of gastric emptying in small animals.     

Idiopathic hepatic veno-occlusive disease causing Budd-Chiari-like syndrome in a cat

Budd-Chiari-like syndrome (BCLS) is a rare clinical entity characterised by portal hypertension and ascites. This report describes a case of BCLS in a cat due to obstruction at the level of the hepatic veins. The diagnosis was based on the clinical findings and a histopathological assessment of the liver demonstrating perivenular fibrosis around the central and sublobular veins. Although these lesions are similar to those observed in man with BCLS, the aetiology in this case remains unknown.     

Spontaneous mutation rates at five coat-color loci in mice

Examination of 1.5 million mice yielded natural mutation rates estimnated from 5.2 million gene reproductions at five specific coat-color loci. The average rates were 11.1 x 10(-6) for forward mutations and 2.7 x 10(-6) for reverse mutations. Differences between the frequencies of mutations at the individual loci were evident.     

MULTICENTRIC LYMPHOMA WITH INTESTINAL INVOLVEMENT IN A DOG

A 5-year-old, male German shepherd dog was evaluated for a 5-week history of vomiting, diarrhea, lethargy, and weight loss. In abdominal radiographs, there was an unusual corrugated appearance within a loop of intestine. Sonographically, this loop also had a similar corrugated appearance with alternating hyperechoic and hypoechoic bands. Lymph nodes within the abdomen and thorax were enlarged, and a thoracic mass was also detected. Ultrasound-guided fine-needle aspirates of the mesenteric lymph nodes were highly suggestive of lymphoma. After postmortem examination, a diagnosis of multicentric lymphoma with involvement of the gastrointestinal tract was made.     

Ultrasonographic assessment of the rate of solid-phase gastric emptying in dogs

Twelve healthy dogs were used in an ultrasonographic assessment of the effect of the composition of a solid meal on the rate of gastric emptying. The dogs were fasted for nine hours before they were fed either a standard or a high energy density test meal, in a cross-over study design. The gastric antrum was visualised with a 6.5 MHz microconvex transducer, and the area inside the elliptical shape defined by the craniocaudal and ventrodorsal diameters of the stomach was measured. Antral images were acquired at regular intervals for six hours after the ingestion of the test meal. Three indices to describe the rate of gastric emptying were computed: the gastric half-emptying time (t1/2), the time to 50 per cent maximal antral area (t50%), and the time of maximal antral area (tmax). The values of t50% and t1/2 calculated for the high energy density meals were significantly longer than for the standard meals, but there was no significant difference between the tmax values.     

Ultrasound imaging of the canine tympanic bulla

A procedure for imaging the canine tympanic bulla, external ear canal and adjacent structures using currently available ultrasound equipment was established. Lateral and ventral transducer positions were identified for this purpose and a 6.5 MHz curvilinear transducer was considered to be optimal. The sonographic appearance of these structures in cadavers and live dogs unaffected by ear disease is documented. Fluid was introduced into the tympanic bullae of the cadavers and its presence could be identified through the bony wall of the bulla. The ability of ultrasound to differentiate between gas and fluid within the bulla has important clinical implications as this is a common occurrence in dogs with middle ear disease. Ultrasound has several advantages over other imaging modalities and the examination procedure was well tolerated by unsedated dogs.     

Oviductal Adenoma in a Mare

A 10-year-old Rocky Mountain Saddle Horse mare was initially presented for erratic estrous cycles, infertility, and an enlarged ovary. The initial differential diagnosis list comprised neoplastic and nonneoplastic ovarian conditions. The primary differential diagnosis of granulosa cell tumor was deemed less likely because of clinical findings and laboratory results. Because of the chronic nature and apparent infertility resulting from the abnormal ovary, surgery was elected to remove the affected ovary. Exploratory laparotomy confirmed the presence of the enlarged ovary; however, a larger oviductal tumor was discovered. Both the ovary and tumor were removed and the mare recovered uneventfully. The mare cycled normally, conceived, delivered a healthy foal, and is currently in late gestation with her second pregnancy.     

TEMPOROMANDIBULAR JOINT MORPHOLOGY IN CAVALIER KING CHARLES SPANIELS

Temporomandibular joint dysplasia has been reported in several breeds of dog. Three Cavalier King Charles Spaniel (CKCS) skulls were examined and radiographed during the course of a separate study and all demonstrated changes consistent with bilateral temporomandibular joint dysplasia. Subsequently, skull radiographs from all CKCS dogs examined at the University of Glasgow Veterinary School between 1991 and 2001 were reviewed (n = 26). Only two of these dogs were radiographed specifically for investigation of the temporomandibular joint, although varying degrees of dysplasia were identified in all dogs where the joints were adequately visualized (n = 20). The head of four CKCS cadavers was also radiographed, and similar changes were found. This finding suggests that temporomandibular joint dysplasia is a widespread asymptomatic condition in the CKCS and should be regarded as a normal morphologic variation rather than a pathologic anomaly. Subtle changes are best seen on lateral oblique radiographs, although marked changes are also visible on dorsoventral views. The rotational angle or angle of articulation of each of the dysplastic mandibular condyles was measured and was related to the severity of the dysplastic changes. However, there was overlap between the values calculated for these abnormal joints and normal ones in other breeds, suggesting this measurement was of limited significance and the shape of the components of the temporomandibular joint are more relevant when assessing this joint for the presence of dysplastic changes.