Icosahedral solids: a new phase of matter?

Numerous examples of metallic alloys have been discovered, the atomic structures of which display an icosahedral symmetry that is impossible for ordinary periodic crystals. Recent experimental results support the hypothesis that the alloys are examples of a new "quasicrystal" phase of solid matter. Observed deviations from an ideal quasicrystal structure can be explained as "phason strains," a special class of defects predicted to be the dominant type of imperfection formed during solidification.     

Dyserythropoeisis, sideroblasts/siderocytes and hemoglobin crystallization in a dog

Dyserythropoiesis characterized by enhanced intramedullary destruction, pathologic sideroblasts and siderocytes, and hemoglobin crystallization was detected in a female Cocker Spaniel presented for poor exercise tolerance. Examination of peripheral blood revealed intraerythrocytic crystals, granulation of erythrocytes, nucleated erythroid cells, reticulocytosis and marked variation in erythrocyte morphology in the absence of anemia. Bone marrow examination revealed sideroblasts, a low M:E ratio and evidence of enhanced intramedullary destruction of erythroid cells. Electron microscopy of peripheral blood and bone marrow confirmed pathologic mitochondrial iron accumulation in erythroid cells and the presence of intraerythrocytic hemoglobin crystals. A cause for the hematologic changes was not identified. After the animal became clinically normal, siderocytes disappeared from peripheral blood but intraerythrocytic crystals and reticulocytosis persisted.     

Retrospective evaluation of xylazine/halothane anesthesia in 125 cattle

A retrospective morbidity and mortality study was carried out on 125 case records of cattle involving xylazine/halothane anesthesia at the Ontario Veterinary College, Guelph between May 1979 and February 1983.     

Evaluation of an enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of infectious bovine rhinotracheitis infection, with results of a preliminary survey

An indirect enzyme linked immunosorbent assay (ELISA) procedure was evaluated against the serum neutralisation test (SNT) for the detection of antibodies to infectious bovine rhinotracheitis virus (bovine herpesvirus type l), using 2028 sera from 166 dairy and 172 beef cattle herds. The results showed the ELISA to give high levels of agreement with the SNT in classifying positive and negative sera (98% and 97% respectively). Such disagreements as did occur involved weakly reactive sera with SNT titres of % or less. A number of sera (n=123) with trace neutralising activity of doubtful diagnostic significance were found to give marginal reactivity with ELISA. ELISA absorbance values were found to be highly correlated with SNT titres (r=0.909) on an overall basis, though agreements were lower with individual sera. The ELISA procedure was quicker, cheaper, and detected more reactors than the SNT. It also allowed results to be obtained with a number of sera which were unsuitable for testing by SNT because of their cytotoxic nature. Analysis of ELISA results showed reactors to be present in 57% of tested sera, representing 81% of cattle herds. Reactor rates for sera and herds in the South Island, (37% and 58%), were significantly lower than for those in the North Island (64% and 88%). Antibody prevalence was also found to be significantly lower in districts having a low annual rainfall (<850 mm), and to be lower in beef cattle than in dairy cattle. A surprising exception to the latter occurred in low rainfall districts, where dairy cattle showed significantly lower reactor rates than local beef animals.     

Dual infections of red deer (Cervus elaphus) by Leptospira interrogans serovars copenhageni and hardjo

On a property in the Nelson District, blood and urine samples were taken from red deer (Cervus elaphus) from which low (<1:100) antibody titres to serovar copenhageni and suspected leptospiral abortions had previously been reported. A total of 27 hinds were sampled. Microscopic agglutination test (MAT) titres in sera ranging from 1:32 to 1:128 were found in six animals. Thirteen leptospiral isolations were made from nine of the 27 urine samples. Four of these were typed as copenhageni and nine as hardjo. Two cultures were prepared from each urine sample and hardjo and copenhageni were both isolated from single urine samples from two animals. None of the 27 deer had serum MAT titres at 1:32 or above to copenhageni.