Sulphido-leukotriene production from peripheral leukocytes and skin in clinically normal dogs and house dust mite positive atopic dogs

Pathogenesis of canine atopy has not been completely elucidated. In humans, sulphido-leukotrienes (s-LT) play a role in atopy, and increased production of s-LT occurs in the skin and peripheral leukocytes after allergen challenge. The study population included 16 clinically normal and 13 atopic dogs. All atopic dogs had in common a positive reaction (4+) to the intradermal injection of house dust mite (allergen of reference). Blood samples and skin biopsies were collected. Sulphido-LT synthesis by peripheral leukocytes after stimulation was measured, and no statistically significant difference was found between clinically normal and atopic dogs. Sulphido-LT concentrations in skin samples from stimulated and unstimulated sites were measured, and no statistically significant difference was detected between clinically normal and atopic dogs or between lesional and nonlesional skin within the atopic group. Clinical signs of atopic dogs were graded by owners and no correlation was found between their severity and cutaneous concentrations of s-LT. In this study there was no increase in s-LT synthesis in atopic dogs.     

Some clinical effects of midazolam premedication in propofol-induced and isoflurane-maintained anaesthesia in dogs during ovariohysterectomy

In a randomised, placebo-controlled clinical trial, anaesthesia was induced with propofol (4 mg/kg) after intravenous premedication with or without midazolam (0.1 mg/kg), in a group of 8 dogs scheduled for ovariohysterectomy. Midazolam administration induced acute behavioural changes, and increased reflex suppression after propofol induction. Compared to the control group, the dose required to obtain loss of the pedal reflex was significantly reduced by 37%, and the end-tidal isoflurane concentration during maintenance, reduced by 23%.     

Ocular fundus images with confocal scanning laser ophthalmoscopy in the dog, monkey and minipig

Confocal scanning laser ophthalmoscopy (CSLO) is a new technique that enables ocular fundus image recording and retinal dynamic angiography to be performed. The ocular fundus image is acquired sequentially, point by point, and is reconstructed on a video monitor at the rate of 25 images per second. The feasibility of performing both ocular fundus image recordings and retinal angiography image recordings were tested on two dogs, two monkeys and two minipigs using a 40° field I + Tech CSLO. Fundus area of each dog, monkey and minipig were examined without any additional optical devices. The ocular fundus and angiography images were recorded, stabilized and analyzed under the same conditions. For each species, all images were easily recorded without any additional optical device in a lighted room and the morphology of the retinal images generated was similar to those obtained with a camera or angiography of higher resolution. Capillary phase or venous times are presented. Image recording at 25 frames/second enabled more retinal dynamics to be demonstrated than with use of regular angiography. This technique is noninvasive and easy to perform if the eye is fixed and eyelids maintained open. It also allows exploration of retinal microvascularization and could be utilized for clinical, pharmacologic and toxicologic investigations as well.     

Effects of Angular Leaf Spot and Rust on Yield Loss of Phaseolus vulgaris

ABSTRACT Three field experiments were conducted in 1997, 1998, and 1999 to investigate the effects of angular leaf spot and rust, separately or combined, on host growth and yield of individual bean plants (Phaseolus vulgaris). In each experiment, three treatments were established by inoculating cv. Carioca with Phaeoisariopsis griseola, Uromyces appendiculatus, or with both pathogens. An additional control treatment was not inoculated, but was sprayed with a fungicide. In the 1997 and 1999 experiments, angular leaf spot reached higher disease levels than rust, whereas in 1998, rust was more severe than angular leaf spot. Host growth, expressed as healthy leaf area duration (HAD), and yield were the highest in 1997 and lowest in 1998. In each experiment, the treatments did not differ significantly to the area under leaf area progress curve, HAD, and healthy leaf area absorption (HAA). All inoculated treatments had significantly more severe disease and less yield than the control treatment. Based on the analysis of 60 plants in each experiment, yield was not related to the areas under disease progress curve for either or both diseases. In 1997 and 1999, yield was related to HAD (R(2) = 0.57 and 0.43) and HAA(R(2) = 0.60 and 0.55). Based on the combined analysis of all 36 plots, angular leaf spot reduced the leaf area because of defoliation, whereas rust did not affect the leaf area. Rust reduced yield more than four times that of angular leaf spot, although the decrease in photosynthesis to angular leaf spot was twice that of rust.     

Enhanced efficiency of electrostatically charged insecticide aerosols

The bioefficacy of a standard domestic aerosol insecticide has been compared with that of a similar spray in which the droplets were electrostatically charged. The aerosol was charged without the need for an external power supply, by enhancing natural charge separation processes that occur during atomisation. The charge-to-mass ratio achieved was 1.1 x 10(-4) C kg-1, compared with 2.2 x 10(-5) C kg-1 for the standard aerosol. Efficiency was assessed for insects in free flight. A direct space-spray application method was used to study the bioefficacy of these aerosols on houseflies, Musca domestica, and an indirect space-spray method on houseflies and mosquitoes, Culex quinquefasciatus. Two levels of concentration of active ingredients were compared. At low concentrations of 1.57 g kg-1 of bioallethrin and 0.29 g kg-1 of bioresmethrin, the charged aerosol achieved a significant reduction in KDT50 (time at which 50% of the flies were knocked down), compared with the standard aerosol. In the direct spray application to houseflies, the KDT50 was reduced by 50%, while in the indirect spray the KDT50 was reduced by 40%. In the indirect spray of mosquitoes, the KDT50 was reduced by 22%. With higher active ingredient concentrations of 2.09 g kg-1 for bioallethrin and 0.39 g kg-1 for bioresmethrin, the charged aerosol also demonstrated faster knockdown than the standard, but the improvement was less marked. In the direct spray application to houseflies, the KDT50 was reduced by 21% compared with the standard aerosol, while in the indirect spray the KDT50 was reduced by 16%. In the indirect spray of mosquitoes, the KDT50 was reduced by 24%. The percentage mortality after 24 h was also increased with the charged aerosol. Charge carried by the droplets results in increased interception of the insecticide, as the droplets are attracted to the insects in flight and space charge effects within the aerosol could cause improved dispersion in the test chamber.     

Erwinia amylovora populations resistant to oxolinic acid in Israel: prevalence, persistence and fitness

Oxolinic acid (OA) has been the only bactericide used against fire blight in pear and quince orchards in Israel since 1998. OA-resistant Erwinia amylovora strains (Ea-OA^R) were detected in several orchards in two restricted areas in the northern Galilee region during 1999–2001. In the following years, resistant strains could not be detected in some of these locations. Documenting the fate of Ea-OA^R strains in commercial orchards at eight sites in northern Israel during 2000/03 revealed that the resistant population appeared irrespective of the number of sprays applied and the severity of the disease. The persistence of the Ea-OA^R populations varied from site to site, ranging from 4 to 20 months; these differences could be attributed to the fire blight management activities of growers. Comparative studies on the fitness of Ea-OA^R and E. amylovora strains sensitive to OA (Ea-OA^S) were conducted in vitro and in planta using two strains of each group. In four of the six comparisons, disease incidence on detached blossoms inoculated with Ea-OA^S was significantly higher than that on blossoms inoculated with Ea-OA^R. In two experiments conducted on 8-year-old pear trees grown under netting, the colonization of Ea-OA^S in blossoms, annual shoots and perennial spurs was significantly higher than that of the Ea-OA^R. In two experiments conducted on 2-year-old trees grown under netting in an experimental station, the incidence of shoots exhibiting fire blight symptoms and the rate of symptom progress within the branches were significantly higher in trees inoculated with Ea-OA^S than in those inoculated with Ea-OA^R. The results of this study suggest that OA-resistant E. amylovora strains have lower fitness than wild-type strains. These findings may have implications for fire blight management.