Use of phenytoin to treat horses with Australian stringhalt

Five horses with Australian stringhalt were treated with 15 mg/kg phenytoin orally for 2 weeks. During the second week of the trial, 3 of the horses were given an additional dose of 10 mg/kg phenytoin. The response to treatment was clinically assessed by grading the severity of the gait abnormality at the walk, trot, turning and backing twice daily. There was a significant (P less than 0.05) improvement in the gait abnormality when pre-treatment values were compared with the mean of the last 3 assessments before treatment stopped. When reassessed 2 weeks after treatment ceased, there remained a significant (P less than 0.05) improvement compared with pre-treatment values at the trot and on backing, but not at the walk or turning. Surface electromyographic recordings were made weekly from the long digital extensor muscle, and there was a change to a near normal recording by the end of treatment. Plasma phenytoin concentrations were monitored during the trial, and the dose rates used achieved a steady state with a mean plasma level of 37 +/- 7 mumol/l. There was wide variability between plasma concentrations in different horses, although there was no difference in absorption between administration of the phenytoin as a paste, or when it was mixed in the feed. Although mild tranquilization was seen after treatment, there were no clinical, haematological or biochemical signs of toxicity from the phenytoin therapy.     

Oxylipin Diversity in the Diatom Family Leptocylindraceae Reveals DHA Derivatives in Marine Diatoms

Marine planktonic organisms, such as diatoms, are prospective sources of novel bioactive metabolites. Oxygenated derivatives of fatty acids, generally referred to as oxylipins, in diatoms comprise a highly diverse and complex family of secondary metabolites. These molecules have recently been implicated in several biological processes including intra- and inter-cellular signaling as well as in defense against biotic stressors and grazers. Here, we analyze the production and diversity of C₂₀ and C₂₂ non-volatile oxylipins in five species of the family Leptocylindraceae, which constitute a basal clade in the diatom phylogeny. We report the presence of species-specific lipoxygenase activity and oxylipin patterns, providing the first demonstration of enzymatic production of docosahexaenoic acid derivatives in marine diatoms. The differences observed in lipoxygenase pathways among the species investigated broadly reflected the relationships observed with phylogenetic markers, thus providing functional support to the taxonomic diversity of the individual species.     

Purification of secretory immunoglobulin A from milk of the brushtail possum (Trichosurus vulpecula)

AIM: To identify and purify secretory immunoglobulin A (sIgA), a key effecter molecule in mucosal immune responses, from milk of the brushtail possum (Trichosurus vulpecula).

METHODS: Milk samples were collected from female possums with pouch young, and clarified by centrifugation and precipitation methods. The clarified fraction was purified by gel filtration and affinity chromatography to yield sIgA. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting techniques were used to assess the purity of the final product, and to identify the heavy (H) chain, light (L) chain and secretory component (SC) of possum sIgA.

RESULTS: Immunoblotting, using antibodies raised against cloned possum sIgA SC and H-chain, and a synthetic peptide fragment of the H-chain, confirmed the identity of the purified protein. The N-terminal amino acid sequence of purified possum sIgA showed strong homology to reported sequences of H-chain variable regions of marsupial immunoglobulins.

CONCLUSIONS: Milk was shown to be a convenient source of mucosal secretion containing sIgA, and a process involving 2 precipitation and 2 chromatography steps produced purified sIgA. This IgA preparation will prove useful for the generation of sIgA-specific immunological reagents for measurement of immune responses in the development of mucosal-based vaccines for biological control of possums.     

Interaction between nutrition and gastrointestinal parasitism in sheep

Effects of gastrointestinal nematode infection on metabolism and nutrient utilisation in sheep are reviewed. Infection induces protein deficiency by increasing the demand for amino acids in the alimentary tract while reducing supply through depression of appetite. Mechanisms through which improved protein nutrition could improve the performance of the host are then discussed. Opportunities for capitalising on such effects are limited by our rudimentary understanding of the cell-mediated immune response in gastrointestinal epithelial tissue. Both resistance of the animal to larval establishment and performance in the face of larval challenge can be enhanced by improved protein nutrition. However, enhanced immune responses may not necessarily be synonymous with improved productivity except at luxurious levels of protein intake, because of apparently competing demands for protein. Such levels of protein nutrition are difficult to achieve in pasture-based systems, because of the protein limiting role of the rumen. Work with protein-protecting tannins to overcome this limitation is discussed. The much more limited evidence for effect of mineral nutrition, particularly copper (Cu), molybdenum (Mo), cobalt (Co) and phosphorus (P), on outcome of larval challenge is also reviewed.     

Comparison of Different Glycerol and Egg Yolk Concentrations Added to Tris‐based Extender for the Collared Peccaries (Tayassu tajacu) Semen Freezing

This study aimed to evaluate various concentrations of egg yolk (5, 10, or 20%) in combination with different concentrations of glycerol (3% or 6%) added to a Tris‐based extender on the post‐thaw characteristics of sperm obtained from Tayassu tajacu. For this purpose, semen from 10 sexually male mature collared peccaries was collected by electroejaculation and evaluated for sperm motility, vigour, viability, morphology and functional membrane integrity. The ejaculates were initially extended in Tris‐fructose plus egg yolk (5%, 10% or 20%). After cooling, the semen was added to Tris‐egg yolk plus glycerol (6% or 12%), resulting in a final concentration of 3% or 6% glycerol of the extender. Straws were frozen using liquid nitrogen and thawed in a water bath at 37°C for 30 s. The frozen–thawed semen was evaluated as reported for fresh semen. After thawing, a significant decrease was verified for sperm motility and vigour, for all the samples in comparison with fresh semen. However, no differences were evidenced among treatments for any sperm characteristics evaluated (p > 0.05), except for the combination between 10% egg yolk and 6% glycerol, which provided the worst preservation of functional membrane integrity (p < 0.05). The interactions between higher concentrations of egg yolk (20%) and glycerol (6%) and also between lower concentrations of the same substances (5% egg yolk and 3% glycerol) added to the Tris‐based extender negatively affected the preservation of the normal sperm morphology after thawing (p < 0.05). In conclusion, the use of Tris‐based extender added to 10% or 20% egg yolk plus 3% glycerol is recommended for effective sperm cryopreservation in collared peccaries.     

The development of multiple cutaneous inverted papilloma following ovariohysterectomy in a dog

Abstract

CASE HISTORY: Ovariohysterectomy was performed on an adult Cavalier King Charles Spaniel. The skin that had been clipped for surgery was noticed to be erythematous 8 days later.

CLINICAL AND PATHOLOGICAL FINDINGS: Poorly defined patches containing multiple papules were visible bilaterally within the clipped skin. These became larger over the following 2 weeks, and samples were collected for histology. Seven days later, the lesions were multiple raised masses, up to 5 cm in diameter. Histology revealed numerous cup-shaped epidermal proliferations extending into the dermis. The presence of keratinocytes with increased quantities of blue-grey cytoplasm, and koilocytosis suggested papillomavirul infection; Canis familiaris papillomavirus (CfPV-2) DNA was amplified from two separate samples. Complete regression was observed 8 weeks after the lesions had been initially observed.

DIAGNOSIS: Multiple inverted papilloma confined to skin that had been clipped for surgery.

CLINICAL RELEVANCE: This is the first time that the development of canine cutaneous papillomas has been associated with surgery. The nature of the association between surgery and development of the papillomas is uncertain. However, it is possible that damage to superficial skin could promote the formation of papillomas. This is the first identification of CfPV-2 in New Zealand.     

Evolutionary analysis of Citrus tristeza virus outbreaks in Calabria,Italy: two rapidly spreading and independent introductions of mild and severe isolates

The evolution of citrus tristeza virus (CTV) from outbreaks occurred in Calabria, Italy, was compared with that of CTV outbreaks reported previously in another two proximal Italian regions, Sicily and Apulia. Examination of four genomic regions (genes p20, p25 and p23, and one fragment of open reading frame 1) showed two recombination events, and phylogenetic analysis disclosed two divergent CTV groups in Calabria: one formed by severe and the other by mild isolates. This analysis, together with others involving population genetic parameters, revealed a low migration rate of CTV between the three Italian regions, as well as significant differences in selective pressures, epidemiology and demography, all affecting the genetic structure of CTV populations.     

Comparison of Methods for Determination of Carbon in Calcareous Soils

The global cycle of carbon (C) has raised attention in recent decades due to the great increase in carbon dioxide levels (CO₂) levels in the atmosphere and its influence on climate change. Calcareous soils represent a significant fraction of the areas with potential for agriculture and have differential attributes, such as high calcium contents, magnesium, carbonates, and pH values. These attributes have been ignored in analytical procedures despite these characteristics, resulting in an overestimation or underestimation of the soil carbon. Several methods have been proposed for determining the soil carbon contents, however, studies evaluating the analytical procedures of C quantification methods, considering the soil characteristics, such as the calcareous soils, are needed, in order to improve their accuracy. Therefore, the objective of this work was to evaluate and compare methods for C determination and to propose adjustments in the methodology for calcareous soil analysis. The Yeomans and Bremner (YB) was the most efficient method for quantification of organic C among the wet oxidation methods. On the other hand, the Donagemma (WB) method underestimated the organic carbon contents. The results showed that the samples must be macerated and pretreated with a hydrochloric acid solution for the use of CHNS-O, in order to eliminate carbonates in the form of nodules and concretions.     

Glycoconjugate histochemistry in the small and large intestine of normal and Solanum glaucophyllum-intoxicated rabbits

Vitamin D participates in mineral homeostasis, immunomodulation, cell growth and differentiation. The leaves of Solanum glaucophyllum contain high levels of 1,25-dihydroxyvitamin D3 as glycoside derivatives and their chronic ingestion generates a hypervitaminosis D-like state. We analyzed changes on carbohydrate expression as a cell differentiation indicator on samples of the small and large intestine of S. glaucophyllum-intoxicated rabbits, using conventional and lectin histochemistry. Male New Zealand white rabbits were intoxicated with S. glaucophyllum during two or four weeks and killed the day after. A group of animals (“possibly recovered group”) were intoxicated during 15 days and killed at day 45 of the beginning of the experiment. We found changes in the lectin binding pattern in the small and large intestine of the intoxicated rabbits. Some of these changes were reverted in the possibly recovered group. Vitamin D could be a new regulator factor of the intestinal glycosylation process.