Influence of three anesthetic protocols on glomerular filtration rate in dogs

OBJECTIVE: To investigate renal function in clinically normal dogs when awake and during anesthesia with medetomidine; xylazine, ketamine, and halothane (XKH) combination; or propofol. ANIMALS: 10 adult female Beagles. PROCEDURES: At intervals of 15 days, dogs were administered medetomidine (0.05 mg/kg, IV); XKH combination (xylazine [1 mg/kg, IV], ketamine [5 mg/kg, IV], and halothane [1% end-tidal concentration]); or propofol (6 mg/kg, IV) to induce anesthesia or no treatment. Glomerular filtration rate was assessed on the basis of renal uptake (RU; determined via renal scintigraphy) and plasma clearance (CL) of technetium 99m-labeled diethylenetriamine pentaacetic acid ((99m)Tc-DTPA). RESULTS: In awake dogs, mean +/- SEM RU was 9.7 +/- 0.4% and CL was 3.86 +/- 0.23 mL/min/ kg. Renal uptake and CL of (99m)Tc-DTPA were not significantly modified by administration of XKH (RU, 11.4 +/- 0.9%; CL, 4.6 +/- 0.32 mL/min/kg) or propofol (RU, 9.7 +/- 0.3%; CL, 3.78 +/- 0.37 mL/min/kg). Half-life elimination time of plasma (99m)Tc-DTPA decreased significantly in XKH-anesthetized dogs, compared with the value in awake dogs (14.4 minutes and 28.9 minutes, respectively). However, glomerular filtration rate was significantly decreased by administration of medetomidine (RU, 3.9 +/- 0.1%), and the time to maximum kidney activity was significantly increased (867 +/- 56 seconds vs 181 +/- 11 seconds without anesthesia). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that anesthesia with propofol or an XKH combination did not alter renal function in healthy Beagles, but anesthesia with medetomidine decreased early RU of (99m)Tc-DTPA.     

Effects of a veterinary student leadership program on measures of stress and academic performance

Assuming leadership roles in veterinary student governance or club activities could be considered an added stressor for students because of the impact on time available for personal and academic activities. The study reported here evaluated the effects of participation in a leadership program and leadership activity across two classes of veterinary students on measures of stress, using the Derogatis Stress Profile (DSP), and on veterinary school academic performance, measured as annual grade-point average (GPA) over a three-year period. Program participants and their classmates completed the DSP three times across the first three years of veterinary school. On average, participating students reported self-declared stress levels that were higher and measured DSP stress levels that were lower than those of the general population. Students were more likely to assume elected or appointed leadership roles while in their first three years of the veterinary degree program if they participated in the optional leadership program and demonstrated lower stress in several dimensions. Some increased stress, as measured in some of the DSP stress dimensions, had a small but statistically significant influence on professional school GPA. The study determined that the most important predictors of students' cumulative GPA across the three-year period were the GPA from the last 45 credits of pre-veterinary coursework and their quantitative GRE scores. The results of the study indicate that neither participation in the leadership program nor taking on leadership roles within veterinary school appeared to influence veterinary school academic performance or to increase stress.     

Planning wetland protection and restoration for the safeguard of ecosystem service flows to beneficiaries

Landscape Ecology - Human activities have led to the degradation of wetlands, impinging on their capacity to deliver essential ecosystem services to society. Wetland restoration now appears an...     

Establishing climate–growth relationships for yelloweye rockfish (Sebastes ruberrimus) in the northeast Pacific using a dendrochronological approach

We applied dendrochronology (tree‐ring) methods to develop multidecadal growth chronologies from the increment widths of yelloweye rockfish (Sebastes ruberrimus) otoliths. Chronologies were developed for the central California coast, a site just north of Vancouver Island, British Columbia, and at Bowie Seamount west of the Queen Charlotte Islands, British Columbia. At each site, synchronous growth patterns were matched among otoliths via the process of cross‐dating, ensuring that the correct calendar year was assigned to all increments. Each time series of growth‐increment measurements was divided by the values predicted by a best‐fit negative exponential function, thereby removing age‐related trends. These detrended time series were averaged into a master chronology for each site, and chronologies were correlated with monthly averages of sea surface temperatures, upwelling, the Northern Oscillation Index, and the Pacific Decadal Oscillation. The two northern growth chronologies positively correlated with indices of warm ocean conditions, especially from the prior summer through the spring of the current year. During the same period, the California chronology positively correlated with indices of cool ocean conditions, indicating an opposing productivity regime for yelloweye rockfish between the California Current and the Gulf of Alaska. Overall, this study demonstrates how tree‐ring techniques can be applied to quickly develop annually resolved chronologies and establish climate–growth relationships across various temporal and spatial scales.     

Agronomic traits of soybean cultivars released in different decades after grafting record‐yield cultivar as rootstock

Breeders have seldom considered the selection for root traits during the genetic improvement in soybean. It is hypothesized that grain yield would be increased by the root function improvement, especially for the current cultivars. The objective of this grafting experiment was to determine the effect of record‐yield cultivars L14 or Z35 as rootstocks on agronomic traits of cultivars released in different decades. A total of 11 cultivars, released in different decades, were used to graft onto L14 or Z35 rootstocks. The agronomic traits were measured in the pot‐culture experiments. Grafting cultivars released in different decades onto L14 or Z35 rootstocks resulted in higher yield, 100‐seed mass and apparent harvest index as compared with those of non‐grafted or self‐grafted plants. Grain yield gain of cultivars grafted onto record‐yield cultivar rootstocks was 0.40 g/plant/year from 1966 to 2006, which was larger than that of non‐grafts and self‐grafts (0.27 g/plant/year). The yield of current cultivars should increase more if their root functions were improved.     

Conservation planning with spatially explicit models: a case for horseshoe bats in complex mountain landscapes

Context

Context Bats are considered as an ecological indicator of habitat quality due to their sensitivity to human-induced ecosystem changes. Hence, we will focus the study on two indicator species of bats as a proxy to evaluate structure and composition of the landscape to analyze anthropic pressures driving changes in patterns.

Objectives

This study develops a spatially-explicit model to highlight key habitat nodes and corridors which are integral for maintaining functional landscape connectivity for bat movement. We focus on a complex mountain landscape and two bat species: greater (Rhinolophus ferrumequinum) and lesser (Rhinolophus hipposideros) horseshoe bats which are known to be sensitive to landscape composition and configuration.

Methods

Species distribution models are used to delineate high-quality foraging habitat for each species using opportunistic ultrasonic bat data. We then performed connectivity analysis combining (modelled) suitable foraging habitat and (known) roost sites. We use graph-theory and the deviation in the probability of connectivity to quantify resilience of the landscape connectivity to perturbations.

Results

Both species were confined to lowlands (<1000 m elevation) and avoided areas with high road densities. Greater horseshoe bats were more generalist than lesser horseshoe bats which tended to be associated with broadleaved and mixed forests.

Conclusions

The spatially-explicit models obtained were proven crucial for prioritizing foraging habitats, roost sites and key corridors for conservation. Hence, our results are being used by key stakeholders to help integrate conservation measures into forest management and conservation planning at the regional level. The approach used can be integrated into conservation initiatives elsewhere.

     

Influence of storage practices on acrylamide formation during potato frying

A number of parameters linked to storage of potatoes were evaluated with regard to their potential to influence the acrylamide formation in French fries. Acrylamide, which is a potential human carcinogen, is reported to be formed during the frying of potatoes as a result of the reactions between asparagine and reducing sugars. This study was conducted using three potato varieties (Bintje, Ramos, and Saturna) typically used in Belgium, The Netherlands, and the northern part of France for French fry and crisp production. Saturna, mainly used in crisp production, appeared to be the least susceptible for acrylamide formation during frying. Especially storage at low temperatures (4 degrees C) compared to storage at 8 degrees C seemed to enhance acrylamide formation due to a strong increase in reducing sugars caused by low-temperature storage. Because of the reversible nature of this physiological reaction, it was possible to achieve a significant reduction of the reducing sugars after a reconditioning of the cold-stored potatoes for 3 weeks at 15 degrees C. All changes in acrylamide concentrations could mainly be explained by the reducing sugar content of the potato (R2 = 0.84, n = 160). This means that, by ensuring a low reducing sugar content of the potato tuber, the risk for acrylamide formation will largely be reduced. Finally the use of a sprout inhibitor did not influence the composition of the potato, and thus acrylamide formation was not susceptible to this treatment.     

Colorimetric evaluation of phenolic content and GC-MS characterization of phenolic composition of alimentary and cosmetic argan oil and press cake

The global phenolic content of argan oil and press cake samples (alimentary and cosmetic) was evaluated using the Folin-Ciocalteu colorimetric method and the phenolic composition of argan oil (alimentary and cosmetic) and press cake (alimentary) samples were analyzed by GC-MS after extraction with 80:20 (v/v) methanol:water and silylation. Identification of chromatographic peaks was made by mass selective detection. Nineteen simple phenols were detected, 16 in press cake, 6 in the alimentary oil, and 7 in the cosmetic oil, among which 15 compounds [3-hydroxypyridine (3-pyridinol), 6-methyl-3-hydroxypyridine, catechol, resorcinol, 4-hydroxybenzyl alcohol, vanillin, 4-hydroxyphenylacetic acid, vanillyl alcohol, 3,4-dihydroxybenzyl alcohol, 4-hydroxy-3-methoxyphenethyl alcohol, methyl 3,4-dihydroxybenzoate, hydroxytyrosol, protocatechuic acid, epicatechin, and catechin] were identified for the first time in such materials.     

Antimicrobial and physicochemical properties of chitosan-HPMC-based films

To prepare composite films from biopolymers with anti-listerial activity and moisture barrier properties, the antimicrobial efficiency of chitosan-hydroxy propyl methyl cellulose (HPMC) films, chitosan-HPMC films associated with lipid, and chitosan-HPMC films chemically modified by cross-linking were evaluated. In addition, the physicochemical properties of composite films were evaluated to determine their potential for food applications. The incorporation of stearic acid into the composite chitosan-HPMC film formulation decreased water sensitivity such as initial solubility in water and water drop angle. Thus, cross-linking of composite chitosan-HPMC, using citric acid as the cross-linking agent, led to a 40% reduction in solubility in water. The water vapor transfer rate of HPMC film, approximately 270 g x m(-2) x day(-1) x atm(-1), was improved by incorporating chitosan and was further reduced 40% by the addition of stearic acid and/or cross-linking. Anti-listerial activity of films was determined on solid medium by a numeration technique. Chitosan-HPMC-based films, with and without stearic acid, inhibited the growth of Listeria monocytogenes completely. On the other hand, a loss of antimicrobial activity after chemical cross-linking modification was observed. FTIR and 13C NMR analyses were then conducted in order to study a potential chemical modification of biopolymers such as a chemical reaction with the amino group of chitosan. To complete the study, the mechanical properties of composite films were determined from tensile strength assays.