Equine atypical myopathy: a review

Atypical myopathy (AM) is an acute rhabdomyolysis syndrome that occurs at irregular intervals in grazing equines. An increasing number of outbreaks have been reported in recent years, including some from countries where the disease has not previously been diagnosed. In this review, clinical and other details of outbreaks of AM are analysed to better define its epidemiological profile. Potential aetiologies are discussed, the short clinical course of AM is described and the main biochemical and pathological findings are considered. Recommendations for medical management are suggested, based on a review of clinical reports. Biochemical and histopathological findings have been integrated in order to characterise the physiopathology of AM. There is an ongoing requirement to record new cases of this syndrome, ideally through an epidemiological network.     

Pharmacokinetics of low‐dose methotrexate in healthy beagle dogs

Methotrexate may be an alternative to ciclosporin in the treatment of canine atopic dermatitis (cAD) as suggested by recent data. The aim of the study was to investigate both the tolerance and the pharmacokinetic behavior of methotrexate (MTX) in plasma, following intravenous (i.v.), subcutaneous (s.c.) or oral (OR) administration over several weeks. Six healthy dogs were given oral MTX once a week, respectively, per dog at 2.5 mg/1 week, 5 mg/4 weeks, 7.5 mg/3 weeks, 10 mg/6 weeks and 12.5 mg/5 weeks. No clinically relevant abnormalities of laboratory parameters were noticed. A high inter‐individual variation of MTX plasma concentration was observed with a suspicion of saturation phenomenon in absorption. To compare with other routes of administration, six healthy beagle dogs followed a crossover design study at 7.5 mg per dog MTX. The absolute bioavailability was 93% for SC injection and 30% for the oral route. The inter‐individual variability was quite low following SC administration compared to oral route. Just as in human, given the substantial variability of oral absorption, clinicians cannot assume consistent oral bioavailability of MTX. Therefore, they may consider switching dogs to the SC route in case of absence of clinical response with a weekly oral dose.     

Diversity of leaf traits related to productivity in 31 Populus deltoides x Populus nigra clones

To test if some leaf parameters are predictors of productivity in a range of Populus deltoides (Bartr.) Marsh. x P. nigra L. clones, we assessed leaf traits and productivity in 2-month-old rooted cuttings from 31 clones growing in 4-l pots in a greenhouse, under conditions of controlled temperature and optimal irrigation. We evaluated four groups of variables describing (1) productivity (total biomass), (2) leaf growth (total leaf number increment and total leaf area increment rate), (3) leaf structure (specific leaf area and nitrogen and carbon contents) and (4) carbon isotope discrimination (delta), which is negatively correlated with time-integrated water-use efficiency. High-yielding clones did not necessarily display high leaf growth rates, but they displayed a larger total leaf area, lower specific leaf area and lower leaf nitrogen concentration than clones with low productivity. Total leaf area was mainly controlled by maximal individual leaf area and total leaf area increment rate (r = 0.51 and 0.56, respectively). Carbon isotope discrimination did not correlate with total biomass, but it was associated with total number of leaves and total leaf area increment rate (r = 0.39 and 0.45, respectively). Therefore, leaf area and specific leaf area were better indicators of productivity than leaf growth traits. The observed independence of delta from biomass production provides opportunities for selecting poplar clones combining high productivity and high water-use efficiency.     

Resveratrol inhibits the activity of equine neutrophil myeloperoxidase by a direct interaction with the enzyme

Resveratrol is a polyphenolic antioxidant present in beverage and food known for its multiple protective effects. We report the inhibitory effects of resveratrol on equine myeloperoxidase (MPO), a hemic peroxidase present in the granules of the neutrophils involved in the inflammatory response. Resveratrol inhibited the production of reactive oxygen species (ROS) by stimulated equine neutrophils by acting as a direct scavenger of the ROS released by the cells but did not modify the degranulation of the stimulated neutrophils as the amounts of released MPO were unchanged. Resveratrol strongly inhibited the chlorination, oxidation, and nitration activities of MPO in a dose-dependent manner. By an original technique of specific immunological extraction followed by enzymatic detection (SIEFED), we demonstrated that resveratrol inhibited the peroxidasic activity of the MPO measured by a direct interaction such as the fixation of resveratrol on the enzyme. The observation of a decrease of the accumulation of compound II suggested that resveratrol acts as an electron donor for MPO reduction.     

Three-dimensional reconstruction of partially 3D-digitized peach tree canopies

A simplified method for building three-dimensional (3D) mock-ups of peach trees is presented. The method combines partial digitizing of tree structure with reconstruction rules for non-digitized organs. Reconstruction was applied at two scales: leaves on current-year shoots (CYS) and shoots on 1-year-old shoots (OYOS). Reconstruction rules make use of allometric relationships, random sampling of shoot attribute distribution and additional hypotheses (e.g., constant internode length). The method was quantitatively assessed for two training systems (tight goblet and wide-double-Y), at a range of spatial scales. For this purpose, light interception properties of reference and reconstructed mock-ups were compared. Mock-up quality depended on scale. Foliage reconstruction on CYS was unsuitable for generating a given CYS. Similarly, CYS reconstruction on OYOS was unsuitable for generating a given OYOS. This is because generic rules derived at the population scale do not consider specific foliage or shoot attributes of a given CYS or OYOS. In contrast, foliage reconstruction on CYS was able to generate OYOS mock-ups having light properties similar to the reference mock-ups. The same held for CYS reconstruction on OYOS for light capture properties at the tree scale. The CYS reconstruction on OYOS was also suitable for deriving OYOS distribution as a function of light interception ability. Reconstruction rules were successfully used to build the vegetation neighborhood of a reference shoot. The proposed method could therefore be used to make 3D tree mock-ups usable for a range of some, but not all, light computations. Because the simplified method allows large time savings, it could be used in virtual experiments requiring large numbers of replicates, such as comparative studies of tree genotypes or training systems.     

Elastic domains regulate growth and organogenesis in the plant shoot apical meristem

Although genetic control of morphogenesis is well established, elaboration of complex shapes requires changes in the mechanical properties of cells. In plants, the first visible sign of leaf formation is a bulge on the flank of the shoot apical meristem. Bulging results from local relaxation of cell walls, which causes them to yield to internal hydrostatic pressure. By manipulation of tissue tension in combination with quantitative live imaging and finite-element modeling, we found that the slow-growing area at the shoot tip is substantially strain-stiffened compared with surrounding fast-growing tissue. We propose that strain stiffening limits growth, restricts organ bulging, and contributes to the meristem's functional zonation. Thus, mechanical signals are not just passive readouts of gene action but feed back on morphogenesis.     

Characterization of the canine skin barrier restoration following acute disruption by tape stripping

The stratum corneum (SC) forms the main part of the permeability barrier of the skin. In mice and in humans, cutaneous barrier disruption can be generated by removing the SC with tape stripping (TS) and the skin barrier function can be assessed by measurement of transepidermal water loss (TEWL). The aim of the present study was to characterize the skin barrier restoration in the dog following mechanical disruption and to analyse the correlation between the skin barrier recovery and TEWL measurement. Thirty sequential TS were performed on 12 sites on four healthy beagle dogs. The number of TS was chosen to ensure a sufficient barrier disruption with a slow recovery. Skin repair was assessed for 72 h by clinical and histological examinations, and TEWL measurements. The results showed that performing 30 TS was adequate to disrupt the skin barrier in the dog. The homeostatic repair response, initiated in the skin, was rapid and characterized by complete restoration of the SC within 72 h, accompanied by greater basal cell proliferation, and dermal eosinophilic inflammation. TEWL was significantly increased by complete removal of the SC but recovered along with restoration of the SC (Scheffe test, P ≤ 0.05). Characterization of a canine model of barrier disruption and restoration and assessment of the skin barrier function by TEWL measurements could help better understand the events implied in skin barrier function. Development of this canine model is also necessary for future studies on the effects of treatments aimed at restoring the skin barrier.     

Rapid MALDI-TOF mass spectrometry identification of Leptospira organisms

Leptospirosis is a worldwide deadly zoonotic disease. Accurate identification of the causative Leptospira spp. spirochetes ascertains the pathogenic status of the isolates, identifies potential source of infection and recognises outbreaks. Species identification is currently based on technically demanding, time and resources consuming serological and molecular methods. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) recently emerged as a first-line method for the accurate identification of bacteria, yet no data issued for Leptospira spp. We investigated the potential of MALDI-TOF-MS for the rapid identification of Leptospira isolates. Starting from a 10(5)organisms/mL suspension, MALDI-TOF-MS yielded an unique protein profile for each one of 19 Leptospira species reference isolates with a 100% reproducibility over 12 repeats, allowing to create a Leptopsira database. MALDI-TOF-MS further accurately identified 20/21 additional reference isolates representative of various serogroups at the species level as Leptospira interrogans (n=12), Leptospira kirschneri (n=5), Leptospira borgpetersenii (n=3), Leptospira noguchii (n=1) with identification score value of 2-2.5. Furthermore, six clinical isolates previously identified by rpoB sequencing, were correctly identified by MALDI-TOF-MS as L. interrogans (n=5) and L. borgpetersenii (n=1) with identification score value of 2-2.6. Identification was achieved in 40 min starting from the Leptospira suspension. MALDI-TOF-MS could complement serological and sequencing-based methods for the first line, rapid identification of Leptospira isolates in the clinical microbiology laboratory.