Structure of a tyrosine phosphatase adhesive interaction reveals a spacer-clamp mechanism

Cell-cell contacts are fundamental to multicellular organisms and are subject to exquisite levels of control. Human RPTPmu is a type IIB receptor protein tyrosine phosphatase that both forms an adhesive contact itself and is involved in regulating adhesion by dephosphorylating components of cadherin-catenin complexes. Here we describe a 3.1 angstrom crystal structure of the RPTPmu ectodomain that forms a homophilic trans (antiparallel) dimer with an extended and rigid architecture, matching the dimensions of adherens junctions. Cell surface expression of deletion constructs induces intercellular spacings that correlate with the ectodomain length. These data suggest that the RPTPmu ectodomain acts as a distance gauge and plays a key regulatory function, locking the phosphatase to its appropriate functional location.     

Pharmacokinetics of single-dose oral pregabalin administration in normal dogs

ObjectiveTo describe the pharmacokinetics of pregabalin in normal dogs after a single oral dose.Study designProspective experiment.AnimalsSix adult Labrador/Greyhound dogs (four females and two males) aged 2.6 (2.6–5.6) years old (median and range) weighing 33.4 (26.8–42.1) kg.MethodsAfter jugular vein catheterization, the dogs received a single oral dose of pregabalin (～4 mg kg^?1). Blood samples were collected at: 0 (before drug administration), 15 and 30 minutes and at 1, 1.5, 2, 3, 4, 6, 8, 12, 24 and 36 hours after drug administration. Plasma pregabalin concentration was measured by HPLC. Noncompartmental analysis was used to estimate pharmacokinetic variables.ResultsNo adverse effects were observed. The median (range) pharmacokinetic parameters were: Area under the curve from time 0 to 36 hours = 81.8 (56.5–92.1) μg hour mL^?1; absorption half-life = 0.38 (0.25–1.11) hours; elimination half-life = 6.90 (6.21–7.40) hours; time over 2.8 μg mL^?1 (the presumed minimal effective concentration) = 11.11 (6.97–14.47) hours; maximal plasma concentration (C_max) = 7.15 (4.6–7.9) μg mL^?1; time for C_max to occur = 1.5 (1.0–4.0) hours. Assuming an 8-hour dosing interval, predicted minimal, average, and maximal steady state plasma concentrations were 6.5 (4.8–8.1), 8.8 (7.3–10.9), and 13.0 (8.8–15.2) μg mL^?1. The corresponding values assuming a 12-hour interval were 3.8 (2.4–4.8), 6.8 (4.9–7.9), and 10.1 (6.6–11.6) μg mL^?1.Conclusions and clinical relevancePregabalin 4 mg kg^?1 PO produces plasma concentrations within the extrapolated therapeutic range from humans for sufficient time to suggest that a twice daily dosing regime would be adequate. Further study of the drug's safety and efficacy for the treatment of neuropathic pain and seizures in dogs is warranted.     

Comparison between tracheal ratio methods used by three observers at three occasions in English Bulldogs

Background

Tracheal hypoplasia is a congenital condition described in mainly brachycephalic breeds and is one component of the brachycephalic obstructive airway syndrome (BOAS). Two radiographic methods have been described to evaluate the dimensions of the tracheal diameter in dogs and to distinguish between hypoplastic and non-hypoplastic tracheas: the tracheal lumen diameter to thoracic inlet distance ratio (TD/TI) and the ratio between the thoracic tracheal luminal diameter and the width of the proximal third of the third rib (TT/3R). The purpose of this study was to compare these two published radiographic methods between observers, different measuring occasions and to investigate the effect on classification of dogs as having hypoplastic or non-hypoplastic tracheas using four previously published mean ratios as cut-offs (<0.11, <0.127 and <0.144 for the TD/TI and <2.0 for the TT/3R method).Three observers evaluated right and left lateral recumbent radiographs from 56 adult English Bulldogs independently on three different occasions. TD/TI and TT/3R ratios were calculated and correlated between measuring occasions. Kappa, observed, positive, and negative agreements were calculated between observers and measuring occasions. Number of hypoplastic and non-hypoplastic dogs for each method and occasion was determined using <0.11, <0.127 and <0.144 as cut-offs for TD/TI and <2.0 for TT/3R.

Results

Intraobserver agreement varied with kappa between 0.45-0.94 for the TD/TI and 0.20-0.86 for the TT/3R method. Interobserver kappa varied between 0.27-0.70 for the TD/TI method and between 0.05-0.57 for the TT/3R method. There was poor agreement in classifying English Bulldogs as tracheal hypoplastic or non-hypoplastic, depending on measuring method, cut-off value and observer.

Conclusions

The diagnostic value of both the TD/TI and TT/3R methods with such poor agreement is questionable, and significantly impacts their reliability for both clinical evaluation of dogs and use in health screening programs.     

Reproductive performance, lipids and fatty acids of mud crab Scylla serrata (Forsskål) fed dietary lipid levels

Natural food (NF, control), artificial diets (AD) containing total lipid levels of 10%, 12% and 14% (AD10, AD12 and AD14) and their combinations (AD10+NF, AD12+NF and AD14+NF) were fed for 112 days to pond‐sourced eyestalk‐ablated mud crab Scylla serrata (625±6.4 g) in tanks in order to determine their effects on reproduction and lipid profiles in broodstock tissues and zoeae. Crabs fed NF had the highest number of spawning followed by crabs fed AD10+NF and AD14+NF. Higher offspring production (number of zoeae) was obtained from crabs fed NF and AD+NF than from AD. As dietary total lipid levels increased, total lipid of broodstock ovaries, hepatopancreas, muscle and zoeae correspondingly increased in which AD+NF promoted higher levels than AD. Increased dietary total lipid levels enhanced lipid classes such as triacylglycerols and phosphatidyl choline levels in zoeae, all higher in crabs fed AD+NF than in AD. The major fatty acids in zoeae, particularly 16:0, 18:0, 18:1n‐9 and 20:4n‐6, 20:5n‐3 and 22:6n‐3, were higher in crabs fed AD+NF than in AD, the contents corresponding to broodstock dietary total lipid levels. A 10% total lipid in AD in combination with NF was sufficient to provide the essential lipids in crabs in the improvement of larval production and quality.     

Agronomic evaluation of Herbaspirillum seropedicae strain ZAE94 as an inoculant to improve maize yield in Brazil

Diazotrophic bacteria applied as a seed inoculant can improve the grain yield of several crops including maize. The current study aimed to test the agronomic efficiency and contribution of biological nitrogen fixation(BNF) of the endophytic diazotroph Herbaspirillum seropedicae strain ZAE94 to maize under field conditions. Eighteen field assays were conducted in four different locations during consecutive years on two hybrids and two varieties of maize in a random block design with four replicates using a peat-based inoculant. The inoculant containing the ZAE94 strain was applied without nitrogen(N)fertilization or with 40 kg N ha~(-1) and was compared to the application of 40 and 80 kg N ha~(-1) without inoculation. Crop productivity and N accumulation in the grain were evaluated in addition to ~(15)N natural abundance(δ~(15)N) to evaluate BNF in the treatments without N fertilization. Fertilization at 40 kg N ha~(-1) plus bacterial inoculation produced crop yields similar to the treatment with 80 kg N ha~(-1) and increased grain N content, especially in the off-season with 40 kg N ha~(-1). The inoculation treatments showed lower δ~(15)N values than the non-inoculated treatments, which was most evident in the off-season. The BNF contributed about 30% of N accumulated in plants inoculated with ZAE94. On average, 64% of the N fertilized plots showed an increase of the parameters evaluated in the inoculated treatments, compared with the control. Inoculation also increased root length, root volume, and leaf area, and these parameters were positively correlated with plant weight using a hydroponic assay. This study revealed that the application of H. seropedicae inoculant increased the amount of N in plants owing to BNF, and there is a better chance of yield response to inoculation under low N fertilizer application in the off-season.     

MICRONODULAR ULTRASOUND LESIONS IN THE COLONIC SUBMUCOSA OF 42 DOGS AND 14 CATS

Micronodular ultrasound lesions have been detected in the colonic submucosa of dogs and cats at our hospital. The lesions had rounded/oval shapes, measured 1–3 mm in size, and exhibited a hypo/anechoic ultrasonographic pattern. To our knowledge, these lesions have not been previously reported in human or veterinary patients. The purpose of this retrospective study was to determine whether micronodular lesions were associated with other abdominal ultrasound abnormalities or clinical findings. Medical records of dogs and cats with sonographic reports describing micronodular lesions within the colonic submucosa were reviewed. Concurrent ultrasonographic abnormalities were recorded and compared with clinical sidgns and follow‐up data. A total of 42 dogs and 14 cats met inclusion criteria. Concurrent sonographic abnormalities included the following: increased colon wall thickness (12.5%); small bowel wall thickening, altered layering, and/or hyperechoic mucosa (45%); abdominal effusion (29%); caudal mesenteric lymphadenopathy (46%); mesenteric lymphadenopathy (27%); and pericolic peritoneal fat reactivity (9%). Fifty of 56 animals presented with diarrhea. Twenty‐seven cases had clinical signs of colitis and ultrasonographic lesions were limited to the colonic submucosa. In nine cases, follow‐up examination at 6–8 weeks showed resolution of clinical and ultrasonographic signs. Ultrasonographic and clinical examinations in 17 patients at 12–18 months and in 20 patients at 18–30 months from initial diagnosis showed resolution of submucosal lesions and clinical signs of enteropathy. The authors propose that micronodular submucosal ultrasound lesions may represent reactive intraparietal lymphoid follicles and may be indicators of colonic inflammatory diseases in dogs and cats.     

Paraneoplastic hypereosinophilia in a dog with intestinal T-cell lymphoma

A 9-year-old, intact male Doberman Pinscher was examined because of anorexia and weakness. Results of a CBC showed severe, microcytic, hypochromic anemia with mild eosinophilia (2944 cells/microL, reference interval 100-1250/microL) and thrombocytosis. Hypoferremia, hypoferritinemia, and a positive fecal occult blood test supported a diagnosis of iron deficiency anemia secondary to chronic intestinal hemorrhage. Abdominal ultrasound evaluation showed a thickened small intestinal loop, of which representative specimens were obtained during exploratory laparotomy. Histologically, the intestinal wall was infiltrated by a neoplastic population of large, round, lymphoid cells with vesicular chromatin, 1 or more prominent nucleoli, and a high number of mitotic figures. The cells were closely admixed with mature eosinophils, but were negative for metachromatic granules with toluidine blue. Immunohistochemically, tumor cells were positive for CD3, and negative for CD21, Pan B, and CD79a. A diagnosis of intestinal T-cell lymphoma was made. Chemotherapy was begun, with 30 mg/m;2 of doxorubicin administered intravenously every 3 weeks. Eosinophil concentration was 880/microL 2 weeks after surgery (on day 15 after presentation) but increased markedly to 62,914/microL on day 30, 62,400/microL on day 37, and 39,444/microL on day 58 after presentation. An association between hypereosinophilia and T-cell lymphoma is well established in human patients, in whom production of IL-5 by neoplastic T cells has been demonstrated. Hypereosinophilia has been reported only rarely with intestinal lymphoma in cats and horses, and with T-cell lymphoma in dogs.     

Polymorphisms in canine ATP7B: candidate modifier of copper toxicosis in the Bedlington terrier

A COMMD1(MURR1) deletion has been reported as the cause of copper toxicosis (CT) in Bedlington terriers. Recent studies identified Bedlington terriers with copper accumulation without homozygous COMMD1 deletions. Wilson disease in humans is a copper storage disorder similar to CT caused by mutations in ATP7B, and COMMD1 has been shown to interact with the ATP7B protein. ATP7B may act as a modifier in CT, allowing for copper accumulation in Bedlington terriers with one deletion or other variations in COMMD1. In this study, ATP7B was cloned and sequence analysis conducted in a subset of Bedlington terriers from a pedigree that does not show complete association between the COMMD1 deletion and CT. Eleven polymorphisms, two in the coding region, were identified in the Bedlington terrier ATP7B gene. However, these are not unique to the Bedlington terrier and pedigree analysis suggests that ATP7B is not a modifier of COMMD1 in this subset of dogs.