The occurrence of equine arteritis virus in Australia

This paper reports the first isolation of equine arteritis virus (EAV) in Australia and serological evidence of exposure to EAV in Australian horses. Twelve Standardbred stallions imported from North America were found to shed EAV in semen. One hundred and seven stallions were tested for serum antibodies to EAV and 73% of Standardbred stallions tested were seropositive as compared to 8% of Thoroughbred stallions. Serum antibody was detected in 71% of Standardbred mares, 6% of Standardbred racehorses and 1% of Thoroughbred mares and racehorses. Examination of stored serums demonstrated that EAV had been present in Australia since at least 1975.     

Canine gastric dilatation-volvulus

Gastric dilatation-volvulus (GDV) is a dramatic and enigmatic disease of large and giant breed dogs characterised by the rapid accumulation of gas in the stomach. This causes gastric dilatation, twisting of the stomach about its long axis, compression of surrounding organs, hypovolaemic and cardiogenic shock, and if untreated, death. It has been estimated that the disease afflicts approximately 60,000 dogs in the USA each year with a mortality rate ranging from 7 to 60 per cent depending on accessibility to adequate veterinary care. The cause is unknown. While diet was at one time believed to be associated with the genesis of the disease, critical review of available data provides no evidence to support this hypothesis. A variety of predisposing or risk factors have been identified but none is suspected of being the cause, indeed, the disorder may have a multiple aetiology. Current thinking suggests that the final common pathway in the development of GDV may be an inhibition of gastric motility and emptying. This could come about through a primary disruption of normal gastric electrical patterns or through the effect of extraneous stressful events that disrupt gastric motility. After dilatation a series of potentially lethal events is unleashed which include compression of the caudal vena cava, pooling of blood in the microcirculation of the viscera and hindlimbs, metabolic acidosis, gastric necrosis, cardiac arrhythmias, disseminated intravascular coagulation, hypotensive and cardiogenic shock and death. Nevertheless, even advanced cases can survive if treated appropriately. If the cause could be identified logical prophylaxis might follow. Studies at the University of Florida have failed to demonstrate any effect of diet on gastric function in large breed dogs, suggesting that diet is probably not the cause of the disease. Researchers at Colorado State University also found no association with diet in clinical patients. Recent studies at the University of Florida have revealed distinct abnormalities in gastric electrical activity in GDV patients. In human patients these abnormalities, called dysrhythmias, have been associated with gastric distention, bloating, delayed emptying, nausea and retching. Unfortunately, dysrhythmias are also present, albeit to a lesser degree, in experimental GDV. These findings leave unanswered the question as to whether abnormalities in gastric motility play a role in the genesis of GDV.     

A grading system for lymphocytic plasmacytic colitis in dogs

Colonic mucosal samples were obtained every 4 weeks for 13 months from 6 clinically normal dogs and from 47 dogs with a clinical diagnosis of chronic inflammatory bowel disease. All samples were graded on a scale of 0-5, based upon the quantity of lymphocytes and plasma cells in the lamina propria, epithelial changes, and the presence of ulcers and erosions. A grade of less than or equal to 2.0 was considered normal and was assigned to 77 of 78 samples from clinically normal dogs and 28 of 48 samples from dogs with diarrhea. A transient increase in cellularity was noted in 1 sample from 1 control dog. Nineteen dogs with clinical disease had obvious histologic abnormalities. The grading scheme described provides the pathologist with an objective criterion for the microscopic evaluation of colonic mucosal samples obtained by endoscopic techniques and offers clinicians a method of assessing the dog's progress and response to therapy.     

Cytokinin from soluble RNA of Escherichia coli: 6-(3-methyl-2-butenylamino)-2-methylthio-9-beta-D-ribofuranosylpurine

We have isolated a compound responsible for the cytokinin activity of soluble RNA from Escherichia coli. The structure, indicated as 6-(3-methyl-2-butenylamino)-2-methylthio-9-beta-D-ribofuranosylpurine, C(16)H(23)N(5)0(4)S, on the basis of low-and high-reso!ution mass spectrometry, was established by unequivocal synthesis. The mass spectra, chromatographic behavior, and ultraviolet spectra of the compounds from natural and synthetic sources were identical.     

Organic Glasses: A New Class of Photorefractive Materials

The performance of amorphous organic photorefractive (PR) materials in applications such as optical data storage is generally limited by the concentration of active molecules (chromophores) that can be incorporated into the host without forming a crystalline material with poor optical quality. In polymeric PR systems described previously, performance has been limited by the necessity of devoting a large fraction of the material to inert polymer and plasticizing components in order to ensure compositional stability. A new class of organic PR materials composed of multifunctional glass-forming organic chromophores is described that have long-term stability and greatly improved PR properties.     

Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation

Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.