Endoscopic-guided diagnosis of and interventional stent placement for nasolacrimal duct obstruction in a horse

Objective

To describe the successful use of endoscopy to visualize and place a soft canine ureteral stent to relieve a chronic nasolacrimal duct (NLD) obstruction in a horse.

Animal Studied

A 7-year-old, Quarter horse gelding.

Procedure

Under general anesthesia, retrograde nasolacrimal endoscopy was performed using an 8.5 Fr Storz Flex XC ureteroscope through the nasal punctum (NP). An obstructive web of fibrous tissue was visualized approximately 20 cm proximal to the NP. A 0.035″/150 cm hydrophilic guidewire was passed normograde from the ventral lacrimal punctum and used to puncture the stenotic tissue. Then, a 5.0Fr/70 cm open-end ureteral catheter was threaded normograde over the guidewire and NLD patency was re-established. The catheter confirmed a NLD length of 30 cm and was then removed. A 5.0Fr/22–32 cm Universa© Soft Ureteral Stent was threaded normograde over the guidewire until the loops of the stent were exposed at each end. The guidewire was removed and the stent loops were sutured in place.

Results

The stent was withdrawn 1 month after the procedure. Telephone follow-up with the client reported significant improvement in the amount of ocular discharge and decreased sensitivity around the face and ears.

Conclusion

Endoscopy is a safe and effective procedure allowing for definitive diagnosis of NLD obstruction and to assist in interventional procedures. Placement of a canine indwelling ureteral stent seems to be an effective alternative treatment option for equine NLD obstruction compared to conventional invasive surgical procedures.     

Identifying environmental drivers of spatial genetic structure of the European pine marten (<Emphasis Type="Italic">Martes martes</Emphasis>)

Context

In a global context of erosion of biodiversity, the current environmental policy in Europe is oriented towards the creation and the preservation of ecological networks for wildlife. However, most of the management guidelines arose from a structural landscape diagnostic without truly taking into consideration species’ needs.

Objectives

We tested whether and how landscape elements influence the functional connectivity of landscapes for a forest specialist species, the European pine marten (Martes martes), in Northeastern France.

Methods

We collected pine marten scats and tissues from 13 evenly distributed study sites across the whole study area in order to test several types of barriers such as highways, waterways, and open agricultural fields. We crossed the results of several methods: spatial autocorrelation analysis, causal modelling framework, and clustering methods.

Results

The study indicates significant genetic differentiation among the sampling sites. A signal of isolation by distance was detected but disappeared after partialling out landscape or barrier resistance. The only model that was fully supported by causal modelling was the one identifying waterways as the main driver of genetic differentiation. Moreover, clustering analyses indicated the presence of genetic clusters, suggesting that pine marten spatial genetic pattern could be explained by the presence of waterways but also by their reluctance to cross open fields.

Conclusions

The current ecological network could thus be improved by increasing permeability of waterways, in particular navigation canals, and by maintaining and restoring forested corridors in agricultural plains.

     

Real-time PCR quantification and spatio-temporal distribution of airborne inoculum of <Emphasis Type="Italic">Puccinia triticina</Emphasis> in Belgium

In order to better understand the epidemiology of Puccinia triticina and the relationship between airborne inoculum and disease severity, a method for quantifying airborne inoculum was developed using volumetric Burkard 7-day spore traps and real-time PCR. The method was applied using a spore trap network from 1 March to 30 June over a 5-year period. At one site, the inoculum was quantified continuously over 3 years, during which it showed a seasonal distribution, with the highest quantities and detection frequencies occurring between May and June. High mean daily quantities (65.8–121.2 spores/day) and detection frequencies (±20 % of days) were also reported after harvest from September to December. In the coldest months of the year, almost no detection was recorded (1–6 % of days). The study results indicate that the absence of inoculum in the air when upper leaves are emerging could be a limiting factor for the risk of epidemics. Mean daily quantities of airborne inoculum (0–131.4 spores/day) were measured from the beginning of stem elongation (GS30) to the flag leaf stage (GS39). These values were well correlated with the disease severity levels measured during grain development. A multiple regression analysis showed that total rainfall in late summer and autumn and mean minimum temperature in winter positively influence spore density between GS30 and GS39 in the following spring (R² = 0.73). This relationship and the patterns of airborne inoculum observed in fields strongly suggest the existence of a ‘green bridge’ phenomenon in Belgium. Our study also showed that the quantification of airborne inoculum or its estimation using a weather-based predictive model could be useful for interpreting disease severity models and avoiding over-estimates of disease risk.     

Kinetic study on the changes in the susceptibility of egg white proteins to enzymatic hydrolysis induced by heat and high hydrostatic pressure pretreatment

A kinetic study was conducted on the effect of heat pretreatment in the temperature range of 50-85 degrees C at atmospheric pressure and of high hydrostatic pressure pretreatment (100-700 MPa) at four temperatures (10, 25, 40, and 60 degrees C) on the susceptibility of egg white solutions (10% v/v, pH 7.6) to subsequent enzymatic hydrolysis by a mixture of trypsin and alpha-chymotrypsin at 37 degrees C and pH 8.0. Both heat pretreatment at atmospheric pressure and high-pressure pretreatment resulted in an increase in degree of hydrolysis (DH) after 10 min of enzymatic reaction (DH10) of egg white solutions, as measured using the pH-stat method, which could be described by a fractional conversion model (based on an apparent first-order reaction kinetic model). The temperature dependence of the corresponding rate constants could be described by the Arrhenius equation. At elevated pressure, a negative apparent activation energy was obtained, implying an antagonistic effect of pressure and temperature. The pressure dependence of the rate constants could be described by the Eyring equation, and negative activation volumes were observed, which demonstrates the positive effect of pressure on the susceptibility of egg white solutions to subsequent enzymatic hydrolysis.     

A Vegetation Index qualifying pasture edges is related to Ixodes ricinus density and to Babesia divergens seroprevalence in dairy cattle herds

Babesia divergens, transmitted by the tick Ixodes ricinus, is the main agent of bovine piroplasmosis in France. This Apicomplexa often is present in asymptomatic carriers; however, clinical cases are rare. While numerous factors are known to influence tick density, no risk factor of contact with B. divergens has been identified for cattle. Our study aimed to explore whether a Vegetation Index could serve as an indirect indicator of within-herd B. divergens seroprevalence. In February 2007, blood samples were taken from all of the cows in 19 dairy cattle herds in Western France and IFAT serology was performed individually to measure B. divergens seroprevalence. The following spring, I. ricinus nymphs were collected by drag sampling along transects on the vegetation of each farm's pasture perimeters. Tick density was related significantly to a Vegetation Index (V.I., ranging from 1 to 5) that took into account the abundance of trees and bushes on the edge of pastures: most ticks (57%) were found in transects with the highest V.I. (covering 15% of the explored surface in the study area). At the farm level, the proportion of transects presenting I. ricinus nymphs was significantly related to B. divergens seroprevalence: the farms with more than 15% of transects with I. ricinus had a significantly higher risk of high seroprevalence. The proportion of pasture perimeters where the V.I.=5 also was significantly related to B. divergens seroprevalence: the farms where more than 20% of transects had a V.I.=5 had a significantly higher risk of high seroprevalence. Given that the Vegetation Index is a steady indicator of the potential I. ricinus density in the biotope, we recommend that the risk of high B. divergens seroprevalence in cows be evaluated using this tool rather than drag samplings.     

Experimental platforms for the investigation of spatiotemporal patterns in the rhizosphere—Laboratory and field scale

The numerous feedback loops between roots, microorganisms, soil chemical and physical properties, and environmental variables result in spatial parameter patterns which are highly dynamic in time. In order to improve our understanding of the related rhizosphere processes and their relevance at the soil–plant system scale, experimental platforms are required. Those platforms should enable (1) to relate small scale observations (nm to dm) to system behaviour, (2) the integration of physical, chemical and biological sampling approaches within the same experiment, and (3) sampling at different time points during the life cycle of the system in question. Here we describe what requirements have to be met and to what extent this has been achieved in practice by the experimental platforms which were set up within the framework of DFG priority programme 2089 “Rhizosphere Spatiotemporal Organisation—a key to rhizosphere functions”. It is discussed to what extent theoretical considerations could be accommodated, in particular for the comparison across scales, i.e., from laboratory to field scale. The latter scale is of utmost importance to overcome the trade‐off between fraction of life cycle covered and the avoidance of unrealistic root length densities.