Dynamics of wheat spindle streak mosaic bymovirus in winter wheat

The dynamics of wheat spindle streak mosaic bymovirus in winter wheat were studied during two crop cycles in a field site with a history of high virus incidence. Individual plants of two susceptible cultivars were sampled from autumn to spring and the presence of virus antigen in roots and leaves was determined by ELISA. Virus incidence was higher in cv. Frankenmuth than in cv. Augusta. During year one, incidence of viral antigen in roots remained very low for four months after sowing, and did not reach maximum levels until the following spring. During year two, incidence of viral antigen in roots rose to maximum levels in autumn, only three months after sowing. These results strongly suggested that root infection occurred in spring as well as in autumn. In both cultivars and in both years, we detected the virus in roots one month prior to its detection in leaves, suggesting that virus moves slowly from roots into leaves. Maximum incidence of virus in leaves occurred in spring of both years, coinciding with the period of symptom development. Typical symptoms (yellow streaks, spindles, and mosaic) were observed in year two, whereas only mild mosaic was observed in year one. Virus antigen was detected in nonsymptomatic leaves from two months after sowing through crop senescence. Because antigen could be detected in roots throughout the crop cycle, and zoosporangia and cystosori of the fungal vector could be detected one and two months, respectively, after sowing, it is possible that wheat spindle streak mosaic bymovirus is acquired and/or spread by the vector during the majority of the crop cycle.     

Congenital cataracts and persistent hyaloid vasculature in a llama (Lama glama)

A 9-month-old llama was evaluated for apparent blindness. Bilateral cataracts were diagnosed and cataract surgery was performed on the right eye. At the time of surgery persistent hyperplastic primary vitreous, persistent hyperplastic tunica vasculosa lentis, and a persistent hyaloid artery were observed. Prior to surgery Power Doppler ultrasound revealed a patent tunica vasculosa lentis OS. Despite reports of a poor success rate for llama cataract surgery, through use of careful tissue handling, phacoemulsification, viscoelastic endothelial protectants, anti-inflammatories, and BSS-Plus irrigating solution, vision was successfully restored in both eyes of the llama.     

Pharmacokinetics of voriconazole after oral administration of single and multiple doses in African grey parrots (Psittacus erithacus timneh)

OBJECTIVE: To determine the pharmacokinetics and safety of orally administered voriconazole in African grey parrots. ANIMALS: 20 clinically normal Timneh African grey parrots (Psittacus erithacus timneh). PROCEDURES: In single-dose trials, 12 parrots were each administered 6, 12, and 18 mg of voriconazole/kg orally and plasma concentrations of voriconazole were determined via high-pressure liquid chromatography. In a multiple-dose trial, voriconazole (18 mg/kg) was administered orally to 6 birds every 12 hours for 9 days; a control group (2 birds) received tap water. Treatment effects were assessed via observation, clinicopathologic analyses (3 assessments), and measurement of trough plasma voriconazole concentrations (2 assessments). RESULTS: Voriconazole's elimination half-life was short (1.1 to 1.6 hours). Higher doses resulted in disproportional increases in the maximum plasma voriconazole concentration and area under the curve. Trough plasma voriconazole concentrations achieved in the multiple-dose trial were lower than those achieved after administration of single doses. Polyuria (the only adverse treatment effect) developed in treated and control birds but was more severe in the treatment group. CONCLUSIONS AND CLINICAL RELEVANCE: In African grey parrots, voriconazole has dose-dependent pharmacokinetics and may induce its own metabolism. Oral administration of 12 to 18 mg of voriconazole/kg twice daily is a rational starting dose for treatment of African grey parrots infected with Aspergillus or other fungal organisms that have a minimal inhibitory concentration for voriconazole < or = 0.4 microg/mL. Higher doses may be needed to maintain plasma voriconazole concentrations during long-term treatment. Safety and efficacy of various voriconazole treatment regimens in this species require investigation.     

Forest recovery since 1860 in a Mediterranean region: drivers and implications for land use and land cover spatial distribution

Context

Land use and land cover (LULC) change is a major part of environmental change. Understanding its long-term causes is a major issue in landscape ecology.

Objectives

Our aim was to characterise LULC transitions since 1860 and assess the respective and changing effects of biophysical and socioeconomic drivers on forest, arable land and pasture in 1860, 1958 and 2010, and of biophysical, socioeconomic and distance from pre-existing forest on forest recovery for the two time intervals.

Methods

We assessed LULC transitions by superimposing 1860, 1958 and 2010 LULCs using a regular grid of 1 × 1 km points, in a French Mediterranean landscape (195,413 ha). We tested the effects of drivers using logistic regressions, and quantified pure and joint effects by deviance partitioning.

Results

Over the whole period, the three main LULCs were spatially structured according to land accessibility and soil productivity. LULC was driven more by socioeconomic than biophysical drivers in 1860, but the pattern was reversed in 2010. A widespread forest recovery mainly occurred on steeper slopes, far from houses and close to pre-existing forest, due to traditional practice abandonment. Forest recovery was better explained by biophysical than by socioeconomic drivers and was more dependent on distance from pre-existing forest between 1958 and 2010.

Conclusions

Our results showed a shift in drivers of LULC and forest recovery over the last 150 years. Contrary to temperate regions, the set-aside of agricultural practices on difficult land has strengthened the link between biophysical drivers and LULC distribution over the last 150 years.

     

IN VITRO EVALUATION OF CONTRAST MEDIUM CONCENTRATION AND DEPTH EFFECTS ON THE RADIOGRAPHIC APPEARANCE OF SPECIFIC CANINE UROLITH MINERAL TYPES

Nine pure mineral types of canine uroliths (bladder or urethral origin only) identified in a chronologic sample from the Minnesota Urolith Center were compared to sequential dilutions of iodinated radiographic contrast medium in vitro. The uroliths studied were those composed of 100% magnesium ammonium phosphate, calcium oxalate monohydrate, calcium oxalate dihydrate, calcium phosphate appatite, calcium hydrogen phosphate dihydrate (brushite), ammonium acid urate, sodium acid urate, cystine, and silica. The radiopacity of the uroliths was classified as radiolucent, isopaque, or radiopaque, as compared to the radiopacity of the contrast medium solutions in which they were placed, using 2.0 mm and 5.0 mm depths in petri dishes radiographed using a table-top technique. A statistically significant relationship was found between the effective atomic number of the uroliths and the effective atomic number of the contrast medium solutions to which they were compared for the endpoints of isopacity, first luceney (in increasing iodine concentration sequence), and optimal visualization of internal architecture. In general, uroliths isopaque or radiolucent in contrast medium solutions weaker than 23.5 mgI₂/ml are most likely ammonium acid urate or sodium acid urate. Uroliths isopaque or radiolucent in contrast medium solutions between 23.5 mgI₂/ml and 44.4 mgI₂/ml are probably magnesium ammonium phosphate, cystine, or silica. Uroliths that remained radiopaque in solutions stronger than 44.4 mgI₂/ml, and particularly those radiopaque in contrast medium solutions stronger than 80 mgI₂/ml, almost always contained calcium. This relative opacity assessment is proposed for use in double contrast cystography as an aid in differentiating urolith mineral types clinically to facilitate appropriate use of medical protocols to dissolve uroliths or to prevent their growth or recurrence.