The influence of various confounding factors on mechanical nociceptive thresholds in the donkey

ObjectiveTo evaluate a mechanical nociceptive threshold (MNT) testing device in the donkey, and to investigate the influence of potential confounders on MNTs generated.Study designProspective, randomised.AnimalsSixteen castrated male donkeys aged 4–9 years, weighing 105–170 kg.MethodsMechanical nociceptive thresholds were measured using an actuator with three pins placed on the dorsal aspect of the distal limb, connected to a force meter. The pins (surface area 15 mm²) were extruded onto the limb by pressurising an air-filled syringe, until the MNT force (when foot-lift was observed) or 25 N (cut-off force) was reached. Effect on MNT of presence of a companion donkey, the limb tested, rate of application of force, testing location, level of distraction, ambient temperature and hair cover at the test site was evaluated. Long and short-term repeatability of MNT was assessed. Data were analysed using general linear models and Mann–Whitney U tests, p < 0.05 was considered significant.ResultsIncreasing the rate of force application significantly increased the mean ± SD MNT from 9.2 ± 2.0 N when applied at 0.4 N sec^?1 to 10.6 ± 2.1 N when applied at 1.2 N sec^?1 (p = 0.001). No other factors significantly influenced MNT. Mean MNT remained stable over a 3 week period, however MNTs were significantly (p = 0.006) higher (12.8 ± 3.0 N cf 10.3 ± 1.9 N) after a 12 month interval.Conclusions and clinical relevanceWhen designing studies measuring MNT in donkeys, rate of application of force must be standardised. Donkeys’ MNTs have good short-term stability suggesting this technique is appropriate for short-term analgesiometry studies; however variability of MNTs over the long-term is greater.     

Ultrastructural morphologic evaluation of the phenotype of valvular interstitial cells in dogs with myxomatous degeneration of the mitral valve

OBJECTIVE: To evaluate morphologic changes in valvular interstitial cells of dogs and to find evidence for disease-associated phenotypic changes in these cells. ANIMALS: 5 clinically normal dogs and 5 dogs with severe mitral valve endocardiosis. PROCEDURE: Mitral valve leaflets were evaluated by use of transmission electron microscopy. Differences in cell type and cell location were identified. RESULTS: A change in cell type toward a myofibroblast or smooth muscle cell phenotype was detected, with the smooth muscle cell type being most common. These cells had long amorphous cytoplasmic extensions, fibrillar cytoplasm, incomplete basal lamina, few mitochondria, and eccentrically placed nuclei but lacked smooth endoplasmic reticulum or Golgi complexes. Remaining valvular interstitial cells had heterochromatic nuclei and produced only minimal quantities of collagen. Compared with normal valves, myxomatous valves ha many interstitial-like cells located adjacent to the endothelium. Deeper within the abnormal valves, cells with a heterogenous phenotype formed groupings that appeared to be anchored to adjacent collagen. CONCLUSIONS AND CLINICAL RELEVANCE: Myxomatous degeneration of the mitral valve in dogs is associated with phenotypic alteration, changing from an interstitial to a mixed myofibroblast or smooth muscle cell phenotype. A closer association between interstitial cells and the endothelium is evident in diseased valves. In response to the disease process, valvular interstitial cells of dogs appear to change toward a smooth muscle phenotype, possibly in an attempt to maintain valve tone and mechanical function.     

Genetic basis of penicillin resistance of S. aureus isolated in bovine mastitis

Background

The blaZ gene encoding penicillin resistance can be located either chromosomally or on plasmids. The aim of this study was to investigate the genetic relationships and to determine the location of the blaZ gene in S. aureus isolated in bovine mastitis in Finland and Sweden.

Methods

Seventy-eight β-lactamase positive S. aureus isolates from bovine mastitis (34 from Finland and 44 from Sweden) were included in the study. The localization of blaZ gene was determined by Southern blotting. The blaZ genes of the isolates were sequenced and the sequences were translated to beta-lactamase proteins and further grouped as different protein signatures. The isolates and, as control, 33 Swedish and 36 Finnish beta-lactamase negative isolates were typed with pulsed-field gel electrophoresis (PFGE).

Results

In 26 out of 34 Finnish isolates (76.5%) and in 25 out of 44 Swedish isolates (56.8%) the blaZ gene was localized on a plasmid. Six different protein signatures were found. One signature was found only in four Swedish isolates, but all other signatures were found both in Finnish and Swedish isolates. The PFGE results revealed a diversity of S. aureus clones. The protein signatures were not clearly associated with certain pulsotypes.

Conclusions

The plasmid location of the blaZ gene was not statistically significantly more common in Finland than in Sweden, and hence does not explain the higher proportion of penicillin-resistant isolates of S. aureus causing bovine mastitis in Finland compared to Sweden.     

Factors that affect equine wound repair.

The rate and outcome of wound healing are determined by many factors,some of which are already in effect when the horse is first presented to the veterinarian. A thorough understanding of wound healing principles,coupled with clear client communication, should enable the practitioner to minimize the number of additional factors that may exacerbate the initial situation.     

Beyond the wetland border: Estimating the impact of roads for two species of water snakes

We used models integrating road maps, traffic volume, and snake movements to examine the potential for roads to contribute to mortality in two species of water snakes that differ in their vagility, use of terrestrial habitats, and conservation status. Road networks and traffic volumes typical of three regions in Indiana, USA, may account for mortality of 14-21% of the population per year in the more vagile, terrestrial, and imperiled copperbelly water snake (Nerodia erythrogaster neglecta) but only 3-5% mortality in the more sedentary, aquatic, and common northern water snake (Nerodia sipedon). The majority (>91%) of road crossings and associated mortality are predicted to occur during overland migrations to other wetlands, suggesting roads bisecting travel routes between wetlands may function as mortality sinks. Our models highlight the proportionately greater risk of mortality for the more vagile and imperiled species, N. e. neglecta, and suggest current wetland conservation strategies that focus on the wetland alone are unlikely to adequately protect wetland biodiversity from certain types of anthropogenic habitat modification. What is needed is a landscape approach to wetland conservation that considers not only the quality of wetlands and nearby terrestrial habitats, but also ensures that terrestrial corridors between wetlands remain permeable and offer safe passage for wildlife.     

The effect of human activity on birds at a coastal bay

I examined the direct and indirect effects of human activity on birds at a coastal bay refuge along the Atlantic Coast. Over the year, human activity varied at different sample sites on the refuge, but people were present on part of the refuge every day, although activity was concentrated on designated paths around a freshwater pond and at a fishing pier. On the refuge (exclusive of the ponds) people were present at the sample sites 17% of the time, birds were present 42% of the time when people were present, but birds were present 72% of the time when people were absent. Human activities, such as jogging or grass mowing, which involved rapud movement or close proximity to roosting birds, usually caused them to flush. Slow-walking bird watchers and clammers did not usually cause birds to flush. Gulls and terns were least affected as they usually relanded where they had been, ducks usually flushed and flew to the centre of the pond, and herons, egrets and shorebirds were most disturbed and flushed to distant marshes. These results suggest that if management objectives include providing roosting areas for migrating shorebirds then some areas must be protected from close and fast-moving human activities.     

Metal Enrichment in Zlatna, a Romanian Copper Smelting Town

A preliminary survey of metal concentrations in soil and vegetable samples was undertaken in the town of Zlatna, in western Romania that is dominated by a large copper smelter. One data set (town survey) consisted of soil samples taken from sites both in the centre of the town (near smelter and school grounds) and the outskirts and included those from roadside verges and wooded areas. The second data set consisted of soil samples taken from vegetable garden plots together with an associated sample of spring onion (Allium fistulosum). The aim of this study was to measure levels of the elements Cu, Zn, Pb, Cd and As in soil samples from Zlatna in general, and to assess their uptake into home grown vegetables and thus into the food chain. Concentrations of the elements of interest in soils and vegetables peaked southwest of the smelter and also in soils near the school in the town centre. Concentrations of elements in soils from the town, including those near the school, had the following ranges: Cu, 41–12,000, geometric mean 863 μg/g; Zn, 89–15,600, geometric mean 920 μg/g; Pb, 32–7860, geometric mean 740 μg/g; Cd, BDL–329.5, geometric mean 3.35 μg/g; As, 15–1440 geometric mean 223 μg/g; Thus, the residents of Zlatna are potentially exposed to levels of these elements that are higher than the recommended guideline values. Mean concentrations of the toxic elements in spring onions were: Cu, 10.2; Zn, 95; Pb, 11; Cd, 0.8; As 2.6 μg/g dry weight.     

Nutritional and physiological responses of young growing rats to diets containing raw cowpea seed meal,protein isolate (globulins), or starch

The nutritional and physiological effects of raw cowpea (Vigna unguiculata (L) Walp.) seed meal, protein isolate (globulins), or starch on the metabolism of young growing rats have been evaluated in 14-day trials. Wet and dry weight gain, feed conversion efficiency, and lipid and protein accretion were significantly reduced as a result of inclusion of seed meal, globulins, or starch in the diet, with growth retardation being most marked with the seed meal. The proportional weights of the small intestine and pancreas were increased by meal diets, and serum cholesterol levels were slightly reduced. The globulins and raw starch also increased relative small intestine weights but had no effect on the pancreas or serum constituents. The effects of cowpeas on rats appeared to be due primarily to the combined actions of globulins, resistant starches, protease inhibitors, and possibly fiber and non-starch polysaccharides on intestinal and systemic metabolism.     

Graduate students' teaching experiences improve their methodological research skills

Science, technology, engineering, and mathematics (STEM) graduate students are often encouraged to maximize their engagement with supervised research and minimize teaching obligations. However, the process of teaching students engaged in inquiry provides practice in the application of important research skills. Using a performance rubric, we compared the quality of methodological skills demonstrated in written research proposals for two groups of early career graduate students (those with both teaching and research responsibilities and those with only research responsibilities) at the beginning and end of an academic year. After statistically controlling for preexisting differences between groups, students who both taught and conducted research demonstrate significantly greater improvement in their abilities to generate testable hypotheses and design valid experiments. These results indicate that teaching experience can contribute substantially to the improvement of essential research skills.