Risk factors for equine laminitis: a systematic review with quality appraisal of published evidence

Epidemiological studies into the risk factors for naturally-occurring equine laminitis are limited. There are a small number of such studies, although the results are inconsistent and remain disputed. The reasons for the conflicting results remain unclear. The aim of this review was to critically evaluate previous research in order to identify publications which provide the best evidence of risk factors for naturally-occurring equine laminitis. A systematic review of English language publications was conducted using MEDLINE (1950-2010), CAB Direct (1910-2010) and IVIS (1997-2010). Additional publications were included by searching bibliographies. Search terms included laminitis, equine, risk factors and epidemiology. Publications which compared a case population to a control population and made inferences about parameters as risk factors for naturally-occurring equine laminitis were included. Information was extracted using predefined data fields, including 18 study quality indicators. In total, 17 publications were fully appraised. Six were considered to provide the most reliable information about risk factors for naturally-occurring laminitis. Information on signalment was well researched and there was good evidence for an association with chronic laminitis and increasing age. There remain inconsistent results for many other horse-level risk factors including gender, breed and bodyweight. Previous publications estimating risk factors for equine laminitis were of reasonable quality, although they were limited in the number and scope of the risk factors studied. High-quality, evidence-based studies are needed to identify further risk factors and to establish consensus over previously identified risk factors for different equine populations.     

Photo-Assisted Degradation,Toxicological Assessment,and Modeling Using Artificial Neural Networks of Reactive Gray BF-2R Dye

This work investigates the degradation of Reactive Gray BF-2R dye (a blend of reactive yellow 145, reactive orange 122 and reactive black 5 dyes) using UV/H₂O₂, Fenton, and photo-Fenton-advanced oxidative processes, with artificial sunlight and UV-C radiations. The photo-Fenton process employing UV-C radiation was the most efficient under the conditions studied. The ideal conditions for the degradation of the dye, determined using a factorial design 2³ and a study of the concentration of hydrogen peroxide ([H₂O₂]), were [H₂O₂] equal to 40 mg L^?1, iron concentration [Fe] of 1 mg L^?1, and pH between 3 and 4. The Chan and Chu non-linear kinetic model predicted the kinetic data with a degradation of over 98% for color and 68% for aromatics after 60 min. The behavior of the chemical oxygen demand fitted the first-order kinetic model well, with a degradation of 64% after 60 min. The Multilayer Perceptron 7-11-2 artificial neural network model enabled to model the degradation process of the aromatics and accurately predict the experimental data. Toxicity tests indicated that the post-treatment samples were non-toxic for Escherichia coli bacteria, and Portulaca grandiflora and Basil sabory seeds. However, they inhibited the growth of Lactuca sativa seeds and Salmonella enteritidis bacteria. The photo-Fenton process with UV-C radiation degraded the dye studied efficiently and the degradation percentages were, on average, 7% and 5% higher for color than those observed when employing the Fenton and UV/H₂O₂ processes, respectively. With the aromatic, however, they were 84% and 62% higher, thus justifying the use of this process.     

Calculating Dry Deposition and Canopy Exchange with the Canopy Budget Model: Review of Assumptions and Application to Two Deciduous Forests

The canopy budget model simulates the interaction of major ions within forest canopies based on throughfall and precipitation measurements. The model has been used for estimating dry deposition and canopy exchange fluxes in a wide range of forest ecosystems, but different approaches have been reported. We give an overview of model variations with respect to the time step, type of open-field precipitation data, and tracer ion, and discuss the strengths and weaknesses of different assumptions on ion exchange within forest canopies. To examine the effect of model assumptions on the calculated fluxes, nine approaches were applied to data from two deciduous forest plots located in regions with contrasting atmospheric deposition, i.e. a beech (Fagus sylvatica L.) plot in Belgium and a mixed sugar maple (Acer saccharum Marsh.) plot in Quebec. For both forest plots, a semi-annual time step in the model gave similar results as an annual time step. Na⁺ was found to be more suitable as a tracer ion in the filtering approach than Cl^? or ${\text{SO}}_4^{2 - } $ . Using bulk instead of wet-only precipitation underestimated the potentially acidifying deposition. To compute canopy uptake of ${\text{NH}}_4^ + $ and H⁺, ion exchange with K⁺, Ca²⁺, and Mg²⁺ as well as simultaneous cation and anion leaching should be considered. Different equations to allocate ${\text{NH}}_4^ + $ vs H⁺ uptake had most effect on the estimated fluxes of the cation that was less important at a plot. More research is needed on the relative uptake efficiency of H⁺, ${\text{NH}}_4^ + $ , and ${\text{NO}}_{_3 }^{\text{ - }} $ for varying tree species and environmental conditions.     

Morphological study of the corpus luteum in the rat

The cyclic related growth and regression of the corpus luteum during four consecutive oestrous cycles of the regular four-day-cycling (ie, 16 days), virgin albino Wistar rat were followed up by light and electron microscopic investigation of the ovaries. After ovulation, follicular granulosa cells differentiated into luteal cells in the newly formed corpus luteum. Based on their specific histological characteristics, four various types of corpus luteum in each stage of the oestrous cycle could be identified. As soon as the luteal cells started to degenerate, the number of fibroblasts progressively increased and apoptotic degeneration of luteal cells was initiated and became most prominent during oestrus. Complete regression of the corpus luteum was seen after 15 days. This study shows a strictly organised pattern of luteal cell growth and degeneration in the corpus luteum of the regular four-day-cycling, virgin Wistar rat. The morphological alterations may be regulated by a hormonal fluctuation.     

Temporal variation and high-resolution spatial heterogeneity in soil CO2 efflux in a short-rotation tree plantation

Soil CO2 efflux (SR) is the second largest carbon flux on earth. We investigated the driving factors of the seasonal change and short-distance spatial variation in SR in a short-rotation plantation of willow (Salix viminalis Orm). Total annual SR ranged from 723 to 1149 g Cm(-2) year(-1). Both an exponential and a logistic model were fitted to the data, with soil temperature at a depth of 5 cm as the independent variable. The R2 values for individual sampling points ranged from 0.83 to 0.95 and from 0.85 to 0.93 for the exponential and logistic models, respectively, indicating that soil temperature largely determined the seasonal variation in SR. Modeled soil SR at 10 degrees C ranged from 1.22 to 1.95 micromol m(-2) s(-1), whereas modeled annual Q(10) values were between 3.31 and 6.13. These high Q(10) values were attributed to the absence of drought during the study in 2005. When the coefficients of the general SR models were replaced by linear dependencies on soil and vegetation-related characteristics, the resulting spatially explicit exponential and logistic SR models explained 85 and 86%, respectively, of the variability within the dataset. The analysis indicated that soil carbon concentration, leaf area index, soil pH and root biomass caused differences in SR at the short distances considered in this study. However, incorporating information on variables considered to account for spatial variability in the model did not result in a higher R2 compared with a simple temperature function. When the general SR models were applied to independent datasets from the same plantation, the logistic model provided a better fit than the exponential model when drought occurred. Drought greatly reduced the annual Q(10) values of SR.     

Restoring tropical forest composition is more difficult,but recovering tree-cover is faster,when neighbouring forests are young

Landscape Ecology - Neighbouring forests constitute biological sources that enable the succession from species-poor systems, such as tree-plantings, to highly diverse forests. However, old forest...     

The influence of methimazole on the thyrotrophic and peripheral activity of thyrotrophin and thyrotrophin-releasing hormone in the chick embryo and growing chicken

Plasma concentrations of thyroxine (T₄) and triiodothyronine (T₃) were profoundly depressed both in chick embryos and growing chickens after methimazole (MMI) treatment. There was no response of T₄ and T₃ levels to TRH or TSH injections in the MMI group, either in embryos or growing chickens.

Peroxidase activity measured in the thyroid gland was significantly higher in embryos and growing chickens treated with MMI. However, neither TRH nor TSH affected this activity 2 hr after injection in either control or the MMI-treated group.

Hepatic 5′-monodeiodinase activity was significantly stimulated in the MMI-treated groups of embryos and growing chickens but only when additional sulphydryl groups (DTT) were provided. In embryos, monodeiodination activity 2 hr after TSH injection was not significantly different from control values for either DTT-stimulated or unstimulated conditions within the control and MMI-infused groups. However, in both control and MMI-treated embryos monodeiodination activity significantly increased 2 hr after TRH injection. In the growing chickens, monodeiodination activity 2 hr after TRH or TSH injection was not significantly different from control values in either stimulated or unstimulated conditions of each group.     

Spatio-temporal litterfall dynamics in a 60-year-old mixed deciduous forest

Introduction  

To increase our understanding of litterfall dynamics in mixed-species forests, seasonal and annual variations in litterfall mass and nutrient concentrations were assessed for a 60-year-old spontaneously developed forest dominated by silver birch (Betula pendula Roth), pedunculate oak (Quercus robur L.), and northern red oak (Quercus rubra L.) in Belgium.     

Potential health implication of in vitro human low-density lipoprotein-vitamin E oxidation modulation by polyphenols derived from Côte d'Ivoire's oil palm species

Antioxidant activities of polyphenolic compounds extracted (PPEs) from ripe fruits of oil palms are investigated by studying their in vitro effects on human low-density lipoprotein (LDL) oxidation. Four oil palm species ( Elaeis guineensis ) are issued from the National Centre of Agronomic Research of Co?te d'Ivoire, of which two are parental varieties (HP1 and HP2), while the other two are crossing varieties (HP3 and HP4). The main identified compounds were rutin (HP3 and HP4) and caffeic and chlorogenic (5-caffeoyl quinic) acids (HP1, HP3, and HP4). The highest total phenolic content was found for HP4, while it was significantly lower for HP2. Antioxidative effects were monitored by Cu(2+)- or 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH)-induced generation of conjugated dienes (lag time and oxidation rate). The highest PPE specific antioxidant activity (SAA) values were obtained with crossing varieties (HP3 and HP4) in the copper-oxidation assay. In the AAPH-oxidation assay, SAA values were comparable for all four varieties. PPEs were effective at preventing LDL-vitamin E depletion in vitro. They could exert direct beneficial antioxidant effects on vitamin E and other antioxidants contained in food and beverages in vivo, within the gastrointestinal (GI) tract. These data could also be of particular importance for a healthier nutrition or the management of chronic diseases by a polyphenol-rich diet.