Diverse strains of Actinobacillus lignieresii isolated from clinically affected cattle in a geographically restricted area.

OBJECTIVE: To investigate whether an outbreak of Actinobacillus lignieresii was caused by one or multiple strains. METHODS: Nine isolates of A. lignieresii were obtained from the lymph nodes of 15 affected cattle from two farms to determine whether a single strain was involved. An enterobacterial repetitive insertion consensus sequence (ERIC) PCR was used for genotyping, and the repeats-in-toxin genes were analysed by PCR and sequencing. RESULTS: Isolates from the two farms belonged to two and three genotypes, with a total of four genotypes detected. Genes of the apxICABD operons of some strains had deletions in the apxIA (~697 bp) and in the apxID (~187 bp) genes. The toxin gene deletions and the ERIC PCR patterns suggested the involvement of different A. lignieresii genotypes. CONCLUSION: There was no evidence that a unique genotype was associated with actinobacillosis on the two farms, confirming that this disease was associated with other contributing factors.

Cutaneous lymphosarcoma in a stallion.

Multiple cutaneous lymphosarcomas were diagnosed in an 8-year-old Thoroughbred stallion presented for evaluation of lumps on its scrotum. Histological examination of skin biopsy samples showed a homogenous pattern of lymphoid tissue suggestive of a T-cell lymphosarcoma. Immuno-histochemical tests showed a positive reaction to Rabbit/Anti-Human T-Cell, CD3 antibodies confirming T-cell lymphosarcoma. The animal was not treated and was subsequently euthanased.

Cypress pollen counts in Israel.

In accordance with the terms of the modern world, this presentation is based on the WWW, with a small change in interpretation: WWW stands for Who? When? and Where?

How to reduce air pollution by Cupressus pollen?

Cypress trees are among the most famous trees of the Mediterranean region. The origin of Cupressus sempervirens is apparently in the East Mediterranean. A nice description of the site of origin of Cupressus was provided by the Roman philosopher Plinius: "cypress trees sprout spontaneously on Mt. Ida on the island of Crete, whenever the soil there is disturbed". The aesthetic shape of the trees, the quality of their timber and their adaptation to harsh environmental conditions has attracted people. Certain varieties of the tree (e.g., var. Pyramidalis) were spread rapidly all over the Mediterranean and since the 16th century were introduced into the Western Hemisphere and other parts of the world. During historical times, Cupressus sempervirens was so widely used in the East Mediterranean countries that it reached the brink of extinction. Nowadays it is planted on a large scale as an ornamental plant as a windbreak and as a forest tree. Such plantations have various impacts on their environment, many positive ones, some negative ones, and some disastrous ones. This last aspect is where cypresses come in.

Molecular evolution of two paralogous tandemly repeated heterochromatic gene clusters linked to the X and Y chromosomes of Drosophila melanogaster.

Here we report the peculiarities of molecular evolution and divergence of paralogous heterochromatic clusters of the testis- expressed X-linked Stellate and Y-linked Su(Ste) tandem repeats. It was suggested that Stellate and Su(Ste) clusters affecting male fertility are the amplified derivatives of the unique euchromatic gene betaCK2tes encoding the putative testis-specific beta-subunit of protein kinase CK2. The putative Su(Ste)-like evolutionary intermediate was detected on the Y chromosome as an orphon outside of the Su(Ste) cluster. The orphon shows extensive homology to the Su(Ste) repeat, but contains several Stellate-like diagnostic nucleotide substitutions, as well as a 10-bp insertion and a 3' splice site of the first intron typical of the Stellate unit. The orphon looks like a pseudogene carrying a drastically damaged Su(Ste) open reading frame (ORF). The putative Su(Ste) ORF, as compared with the Stellate one, carries numerous synonymous substitutions leading to the major codon preference. We conclude that Su(Ste) ORFs evolved on the Y chromosome under the pressure of translational selection. Direct sequencing shows that the efficiency of concerted evolution between adjacent repeats is 5-10 times as high in the Stellate heterochromatic cluster on the X chromosome as that in the Y-linked Su(Ste) cluster, judging by the frequencies of nucleotide substitutions and single-nucleotide deletions.

Relationship between potassium administration, hyperkalaemia and the electrocardiogram: an experimental study.

Hyperkalaemia affected the equine myocardium. The minimum plasma potassium concentration required to induce electrocardiographic changes was 6.2 mmol/litre and severe cardiotoxic effects were observed at levels of 8.0 to 10.1 mmol/litre in this experimental situation. The most consistent sign of hyperkalaemia was broadening and flattening of the P wave, which was generally associated with a change in T waves in the chest lead from negative to positive. The more pronounced the hyperkalaemia, the less pronounced the P wave and the more peaked positive the T wave. Severe hyperkalaemia was associated with various arrhythmias invariably associated with the presence of broad flat or absent P waves and upright T waves in chest leads. Caution against extrapolation from the experimental to the clinical situation must be exercised because of many complex interacting factors. Hyperkalaemia is difficult to induce experimentally and, unless associated with disease, is unlikely to occur in the horse.

Effect of stress on steroid hormone levels in racehorses.

Cortisol and testosterone were measured by radioimmunoassay in plasma samples from race horses. None of 6 stressed male horses had low cortisol levels but testosterone levels (0.81 +/- 0.15 nmol/l) were significantly lower than in healthy horses (1.86 +/- 0.31 nmol/l). The conclusion was made that adrenocortical insufficiency is not a common association of stress in race horses. The reduction in testosterone levels is probably a nonspecific response similar to that seen in other species.