A dose‐escalation study of combretastatin A4‐phosphate in healthy dogs

Combretastatin A4 ‐Phosphate (CA4P ) is a vascular disrupting agent revealing promising results in cancer treatments for humans. The aim of this study was to investigate the safety and adverse events of CA4P in healthy dogs as a prerequisite to application of CA4P in dogs with cancer. Ten healthy dogs were included. The effects of escalating doses of CA4P on physical, haematological and biochemical parameters, systolic arterial blood pressure, electrocardiogram, echocardiographic variables and general wellbeing were characterised. Three different doses were tested: 50, 75 and 100 mg m^?2. At all 3 CA4P doses, nausea, abdominal discomfort as well as diarrhoea were observed for several hours following administration. Likewise, a low‐grade neutropenia was observed in all dogs. Doses of 75 and 100 mg m^?2 additionally induced vomiting and elevation of serum cardiac troponine I levels. At 100 mg m^?2, low‐grade hypertension and high‐grade neurotoxicity were also observed. In healthy dogs, doses up to 75 mg m^?2 seem to be well tolerated. The severity of the neurotoxicity observed at 100 mg m^?2, although transient, does not invite to use this dose in canine oncology patients.     

Electromyographic activity of the hyoepiglotticus muscle and control of epiglottis position in horses

OBJECTIVE: To determine whether the hyoepiglotticus muscle has respiratory-related electromyographic activity and whether electrical stimulation of this muscle changes the position and conformation of the epiglottis, thereby altering dimensions of the aditus laryngis. ANIMAL: 6 Standardbred horses. PROCEDURE: Horses were anesthetized, and a bipolar fine-wire electrode was placed in the hyoepiglotticus muscle of each horse. Endoscopic images of the nasopharynx and larynx were recorded during electrical stimulation of the hyoepiglotticus muscle in standing, unsedated horses. Dorsoventral length and area of the aditus laryngis were measured on images obtained before and during electrical stimulation. Electromyographic activity of the hyoepiglotticus muscle and nasopharyngeal pressures were measured while horses exercised on a treadmill at 50, 75, 90, and 100% of the speed that produced maximum heart rate. RESULTS: Electrical stimulation of the hyoepiglotticus muscle changed the shape of the epiglottis, displaced it ventrally, and significantly increased the dorsoventral length and area of the aditus laryngis. The hyoepiglotticus muscle had inspiratory activity that increased significantly with treadmill speed as a result of an increase in phasic and tonic activity. Expiratory activity of the hyoepiglotticus muscle did not change with treadmill speed in 4 of 6 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Findings reported here suggest that contraction of the hyoepiglotticus muscle increases dimensions of the airway in horses by depressing the epiglottis ventrally during intense breathing efforts. The hyoepiglotticus muscle may be an important muscle for dilating the airway in horses, and contraction of the hyoepiglotticus muscle may induce conformational changes in the epiglottis.     

Characterization of ileal bacterial microbiota in newly-weaned pigs in response to feeding lincomycin, organic acids or herbal extract

The changes of ileal bacterial microbiota in pigs during the first 2 weeks post-weaning in response to feeding lincomycin, organic acids or herbal extract were characterized using 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis (DGGE) profiling, DNA sequencing, and real-time PCR (QPCR) techniques. Both time post-weaning and the dietary treatments resulted in a shift of the microbiota composition. While time post-weaning mostly influenced Clostridium group, the feed additives increased the population of Lactobacillus and related lactic acid bacteria by ≥ 3-fold.     

The effect of pH and calcium on copper availability to the springtail Folsomia candida in simplified soil solutions

The effect of pH and calcium on copper bioavailability to the springtail Folsomia candida was determined by assessing uptake kinetics upon copper exposure for 15 days in simplified soil solutions. A slight bioaccumulation of copper was observed in all treatments and controls. The effect of exposure concentration and calcium level on copper accumulation was not significant. Although pH and time slightly but significantly affected copper concentrations in the body, copper uptake rates were not significantly different from zero. This suggests that copper uptake in F. candida exposed to sub-lethal copper concentrations in soil pore water is not affected by pH and calcium.     

Molecular epidemiology and antimicrobial resistance of Salmonella typhimurium DTI04 on Ontario swine farms.

This study was conducted to examine antimicrobial resistances, plasmid profiles, and pulsed-field gel electrophoresis patterns of 80 Salmonella Typhimurium (including var. Copenhagen) DT104 strains (including DT104a and DT104b) recovered from pig and environmental fecal samples on 17 swine farms in Ontario. No resistance was observed to amoxicillin/clavulanic acid, apramycin, carbadox, cephalothin, ceftriaxone, ceftiofur, cefoxitin, ciprofloxacin, nalidixic acid, trimethoprim, and tobramycin. However, the isolates exhibited resistance against 4 to 10 antimicrobials with the most frequent resistance being to sulfonamides (Su), ampicillin (A), streptomycin (S), spectinomycin (Sp), chloramphenicol (C), tetracycline (T), and florfenicol (F). Thirteen distinct resistance patterns were determined but 88% of isolates shared the typical resistance pattern "ACSpSSuT." Twelve different plasmid profiles were observed; the 62 MDa virulence-associated plasmid was detected in 95% of the isolates. The 2.1 MDa plasmid was the second most frequent one, which was harbored by 65% isolates. The isolates were classified into 23 distinct genotypes by PFGE-SpeI + BlnI when difference in at least one fragment was defined as a distinct genotype. In total, 39 distinct "types" were observed when defining a "type" based on the combination of antimicrobial resistance, plasmid pattern, and PFGE-SpeI + BlnI for each isolate. The highest diversity was 0.96 (95% CI: 0.92, 0.96) for the "type" described above followed by 0.92 (95% CI: 0.88, 0.93) for PFGE-SpeI + BlnI. The diversity of DT104 isolates indicates there might be multiple sources for this microorganism on swine farms. This knowledge might be used to track these sources, as well as to study the extent of human salmonellosis attributed to pork compared to food products derived from other food-producing animals.     

Protecting the African elephant: A dynamic bioeconomic model of ivory trade

A dynamic bioeconomic model of ivory trade is used to investigate the efficacy of conservation payments, tourism benefits, quota regimes and a trade ban on the protection of the African elephant (Laxadonta africana). The model consists of four ivory exporting regions and one demand region. Results indicate that a trade ban might not be successful in maintaining elephants, even if it increases the costs of marketing ivory and leads to a stigma effect that reduces demand. Indeed, trade in elephant products may offer some hope for the elephant, but only if there exist effective institutions that translate in situ protection into economic values.     

Extracting soil microarthropods with olive oil: A novel mechanical extraction method for mesofauna from sandy soils

Many soil ecologists still encounter practical difficulties when extracting microarthropods from the soil. Methods using a humidity gradient, established by the use of a heat source, for collecting soil animals appeared not sufficiently efficient in case of sandy soils. For such type of soils, flotation techniques proved more suitable. The use of toxic or aggressive flotation fluids like kerosene, dibromo ethane, carbon tetrachloride and heptane, however, makes these methods less favourable. To circumvent this problem, a novel technique has been developed based on the flotation principle but using olive oil. The method uses a pumping system that injects olive oil at the base of a Perspex column in which the soil sample is suspended in water using a propeller. In this way, intensive contact between oil droplets and the organisms is established, increasing extraction efficiency. After stopping the propeller, animals can easily be collected from the oil floating to the water surface. Adding coloured mites to soil samples was used to determine extraction efficiency of the method. Average (±SD) recoveries of 82.7 ± 7.4% (n = 34) and 89.7 ± 10.0% (n = 10), respectively were obtained when extracting storage mites and predatory mites from a sandy soil.     

Effect of Cropping System on Physical Properties of Clay Soil Under Intensive Rice Cultivation

Cropping systems are thought to alter soil quality in paddy rice fields. This study was conducted to quantify the long‐term effects of continuous crop production under different cropping systems with different crop rotations on physical properties of alluvial clay soil in the Mekong Delta, Vietnam. Soil samples were collected from four treatments: (i) traditional intensive rice monoculture with three rice crops per year (R–R–R); (ii) rotation with two rice crops and maize (R–M–R); (iii) rotation with two rice crops and mung bean (R–Mb–R); and (iv) rotation with one rice and two upland crops, mung bean and maize (R–Mb–M). We hypothesized that cropping systems with rotations of upland crops and their temporary beds improve the physical quality of paddy rice soil; hence, they are better options towards sustainable agriculture. Results show an improvement of soil physical quality for systems with two rice crops and one upland crop (R–M–R and R–Mb–R) and those with one rice crop with two upland crops (R–Mb–M) compared with intensive rice monoculture (R–R–R). This was translated in decreased bulk density and soil strength, increased soil organic carbon and total porosity, and higher aggregate stability index, plant‐available water capacity, and Dexter's S index, especially at depths of 10–20 and 20–30 cm. The systems with different upland crops (maize or mung bean) showed similar high physical quality improvement. To maintain soil quality in future seasons, introducing a cropping system with at least one upland crop in rotation with rice is recommended. Copyright © 2014 John Wiley & Sons, Ltd.