A potential early clinical phenotype of necrotizing meningoencephalitis in genetically at‐risk pug dogs

BackgroundNecrotizing meningoencephalitis (NME) in the pug dogs is a fatal neuroinflammatory disease associated with rapid progression and poor response to conventional immunosuppressive therapy. Diagnosis is typically made after severe neurological abnormalities have manifested.Hypothesis/ObjectivePug dogs at genetic risk for NME might manifest neurological abnormalities before developing pathognomonic clinical signs of NME.AnimalsThirty‐six pug dogs less than 4 years of age asymptomatic for NME.MethodsProspective observational cohort study with germline genome‐wide genotyping. Neurological examinations were performed 4 weeks apart to document reproducible findings of central nervous system disease. Magnetic resonance imaging, cerebrospinal fluid analysis, and testing for infectious diseases were performed in all pugs with reproducible abnormalities detected on neurological examination.ResultsThe overall risk allele frequency in this cohort was 40%; 5 (14%) dogs were high risk, 19 (53%) dogs were medium risk, and 12 (33%) dogs were low genetic risk for NME. Reproducible abnormalities detected on neurological examination were identified in 8/24 (33%) genetically at‐risk dogs and 0/12 (0%) low risk dogs. Clinical abnormalities included multifocal spinal pain in 8/8, reduced menace response in 5/8, and lateralizing postural reaction deficits in 5/8 pugs. There was a strong association between genotype risk and the presence of this clinical phenotype (P = .03).Conclusions and Clinical ImportanceOur findings suggest the presence of a novel early clinical phenotype of NME in apparently asymptomatic genetically at‐risk pugs which might be used to plan early diagnostic and therapeutic clinical trials.     

Effects of water availability and fertilization on nitrogen cycling in a stand of Pinus radiata

Nitrogen cycling was studied for four years (1983–1987) in an N-deficient 10-year-old stand of Pinus radiata growing on a yellow podzolic soil which had a low water-holding capacity. Trees were subjected to combinations of irrigation of N-fertilization resulting in a wide range of N uptake and tree growth. Net mineralization, plant uptake and leaching of soil N was monitored using a sequential coring and in-situ incubation technique. Nitrogen concentrations were measuredd monthly in live needles and litterfall. Average rates of weight loss and release of N from decomposing litter were estimated over a 3-year period using a budgeting approach.

Trees responded only to N (not to P, and there was no N×P interaction), but there was a large positive interaction between N supply and water availability. Response to fertilizer averaged + 24% over a 4-year period, but was zero during a growing-season which contained a 4-month drought. Irrigation alone increased growth by 60%, but in combination with high N availability growth increased 2–3 fold. Annual uptake of N ranged from <10 (irrigated plots in years 2 and 3 after enhanced mineralization during the initial year) to 166 kg ha⁻¹ (during a wet growing season following heavy N fertilization). Although soil mineral-N concentrations were elevated for only about 1 year after fertilization, fertilization enhanced rates of N mineralization throughout the soil N mineralization may have resulted from re-mineralization of the large quantity (147 kg soil N mineralization may have resulted from re-mineralization of the large quantity (147 kg ha⁻¹) of fertilizer N immobilized by the soil during the initial 8 months after fertilization, or the N released from decomposition of fine roots having higher N content. Nitrification was negligible in unfertilized soils, but increased markedly 50–100 days after fertilization and resulted in the leaching of about 60 kg N ha⁻¹ during autumn and winter of the first year after fertilization. Fertilized soils have continued to nitrify readily. Irrigation increased rates of weight loss and N release from decomposing litter.

The rate of N uptake by trees markedly affected the concentrations of N in newly emerging and older needles, and the concentration of N in needlefall. The weighted mean concentration of N in annual needlefall ranged from 0.42% in the irrigated-only plot (most N-stressed) to 0.94% in the heavily fertilized plot during the first year after treatment. These weighted concentrations are a useful index of N uptake from the soil and of growth rate where water supply is not limiting. Except for the initial year after heavy N fertilization, annual uptake of N was equivalent to annual soil N mineralization, and N uptake was positively linearly correlated with annual basal-area increment of trees.     

Inelastic electron tunneling spectroscopy

Inelastic electron tunneling spectroscopy is a useful technique for the study of vibrational modes of molecules adsorbed on the surface of oxide layers in a metal-insulator-metal tunnel junction. The technique involves studying the effects of adsorbed molecules on the tunneling spectrum of such junctions. The data give useful information about the structure, bonding, and orientation of adsorbed molecules. One of the major advantages of inelastic electron tunneling spectroscopy is its sensitivity. It is capable of detecting on the order of 10(10) molecules (a fraction of a monolayer) on a 1-square-millimeter junction. It has been successfully used in studies of catalysis, biology, trace impurity detection, and electronic excitations. Because of its high sensitivity, this technique shows great promise in the area of solid-state electronic chemical sensing.     

In situ imaging of the endogenous CD8 T cell response to infection

Mounting a protective immune response is critically dependent on the orchestrated movement of cells within lymphoid organs. We report here the visualization, using major histocompatability complex class I tetramers, of the CD8-positive (CD8) T cell response in the spleens of mice to Listeria monocytogenes infection. A multistage pathway was revealed that included initial activation at the borders of the B and T cell zones followed by cluster formation with antigenpresenting cells leading to CD8 T cell exit to the red pulp via bridging channels. Strikingly, many memory CD8 T cells localized to the B cell zones and, when challenged, underwent rapid migration to the T cell zones where proliferation occurred, followed by egress via bridging channels in parallel with the primary response. Thus, the ability to track endogenous immune responses has uncovered both distinct and overlapping mechanisms and anatomical locations driving primary and secondary immune responses.     

Protein kinase C regulates ezrin-radixin-moesin phosphorylation in canine osteosarcoma cells

The development of metastasis is the most significant cause of death for both canine and human patients with osteosarcoma (OS). Ezrin has been associated with tumour progression and metastasis in human, canine and murine OS. Ezrin activation is dynamically regulated by protein kinase C (PKC) during metastatic progression in human and murine OS. To include the dog in the development of therapeutics that target ezrin biology, we characterized four new canine OS cell lines and confirmed the relationship between PKC and ezrin in these cells. Three of four cell lines formed tumours in mice that were histologically consistent with OS. All cell lines were markedly aneuploid and expressed ezrin and PKC. Finally, both ezrin phosphorylation and cell migration were inhibited using a PKC inhibitor. These data suggest that an association between PKC-mediated activation of ezrin and the metastatic phenotype in canine OS cells.     

Modelling of sorption experiments and seepage data of an Amazonian Ultisol subsoil under cropping fallow

The results of physico-chemical investigations of an Ultisol subsoil under a 2-year old fallow in eastern Amazonia are presented. Subsoil chemistry was studied using 4 different approaches: i) concentrations of H, Na, K, Ca, Mg, Mn, Al, and Fe in seepage water were measured under field conditions, ii) the equilibrium soil chemistry was studied in sequential batch experiments where the soil was treated with different solutions, iii) results of batch experiments were simulated with a chemical equilibrium model, and iv) the seepage data were calculated using selectivity coefficients obtained by modelling the batch experiments. The model included multiple cation exchange, precipitation/dissolution of Al(OH)₃ and inorganic complexation. Cation selectivity coefficients were pK_x/Ca^sel: X = Na: 0.3, K: 0.8, Mg: ?0.1, and Al: 0.4. The amount of cations sorbed ranged from ?0.2 to 2.0 (K), ?0.7 to 2.3 (Mg), ?1.6 to 1.8 (Ca), ?4.8 to 3.6 (Al) and 0.0 to 8.5 (Na) mmol_c kg^?1. The model predictions were good with values lying within 0.3 pH units (for the pH range 3.7 to 7.2), and 3% of CEC for individual cations. The most important proton buffer reaction seemed to be the dissolution of gibbsite and a large release of Al into the soil solution. When selectivity coefficients obtained by the modelling procedure were used to predict the field data for cation concentrations in the seepage water, they decreased in the following order: Na > K > Ca > Mg > Al. These calculated values were similar to the measured order: Na > Ca > K ≈ Mg > Al. Thus the options for managing these soils should be carefully chosen to avoid soil acidification which may result from inappropriate use of fertilizer during the cropping period.     

Comparison of dot enzyme-linked immunosorbent assay (dot-ELISA) with other serological tests for the detection of Brucella antibodies in bovine sera

A dot Enzyme-linked Immunosorbent Assay (dot-ELISA), using whole cell Brucella abortus antigen dotted on the nitrocellulose membrane bound to a plastic strip (dipstick) was employed for the detection of Brucella antibodies in bovine sera. The results were compared with that of serum agglutination (SAT), Rose Bengal plate agglutination (RBPT) and Complement Fixation test (CFT). All the four tests gave negative reaction in 127 sera obtained from a brucellosis free herd. Testing of 549 sera from a chronically infected herd revealed 57 positive and 447 negative animals in all the four assays. Of the remaining 45 sera, 34 were positive in dot-ELISA. Six of these cases were independently detected by dot-ELISA while 28 showed positive reactions in combination with other tests. When serum samples from 158 aborted cases were subjected to dot-ELISA, 79 were found positive. Of these dot-ELISA positive cases, 71 gave positive reaction in SAT, 72 in RBPT and 78 in CFT. B. abortus biotype 3 was isolated from 34 of the 98 aborted fetuses examined.