Peripheral neuroblastoma in a young labrador retriever

A 2-year-old Labrador Retriever developed atrophy of the right temporal muscle, subsequently showed generalized seizure and died 2 months after the clinical onset. Postmortem examination revealed the tumor masses in the right mandibulopharyngeal area, nasopharynx and intracranial space. Histopathologically, these tumor masses were composed of small round neoplastic cells and neuropil-like stroma separated by fibrovascular septa. In the neoplastic masses, small neoplastic cells with round to oval hyperchromatic nuclei and scanty cytoplasm predominated, and angulated neoplastic cells with larger nuclei and moderate cytoplasm were scattered. Immunohistochemically, neoplastic cells were positive for neuron specific enorase, neurofilament protein, chromogranin A, synaptophysin and tyrosine hydroxylase. Based on these findings, this case was diagnosed as peripheral neuroblastoma, presumably originated from the sympathetic ganglion, maybe right craninal cervical ganglion.     

Effects of salivary gland extract from Rhipicephalus sanguineus on IgG subclass production and cytokine mRNA expression in mononuclear cells of canine peripheral blood

The effects of salivary gland extract (SGE) from R. sanguineus were examined on the production of IgG1 and IgG2 and the mRNA expression of IFN-gamma, IL-2, IL-4, IL-5 and IL-10 in the mononuclear cells from canine peripheral blood, treated with concanavalin A (ConA) in vitro. SGE suppressed the ConA-induced production of IgG2. It also inhibited the expression of IFN-gamma, IL-2 and IL-5 mRNA in a dose-dependent manner. No dose-dependent suppression was observed of IL-10 mRNA expression although a significant effect was observed at a SGE protein concentration of 25 microg/ml. SGE had no effect on the mRNA expression of IL-4. These results suggest that the suppression of IgG2 production by SGE from R. sanguineus was caused by the suppression of IFN-gamma production.     

A comparative pathological study on canine necrotizing meningoencephalitis and granulomatous meningoencephalomyelitis

Canine necrotizing meningoencephalitis (NME) and granulomatous meningoencephalomyelitis (GME) were compared pathologically. Gross observation exhibited lateral ventricular dilation and discoloration, malacia and/or cavitation of the cerebrum in NME. On the contrary, gross changes were milder in GME, except for occasional visible granulomatous mass formation. Histopathologically, the lesions of NME were distributed predominantly in the cerebral cortex and various degrees of inflammatory and necrotic changes were observed according to clinical stages. Besides, microscopic lesions of GME were mainly distributed in the white matter of the cerebrum, cerebellum and brainstem, which are characterized by perivascular cuffing, multiple granulomas and leptomeningeal infiltrates. Although macrophages and lymphocytes were predominant in the inflammatory lesions of both disorders, macrophages in GME transformed into epithelioid cells and exhibited more massive infiltration. Although lectin RCA-1-reactive cells were numerous in both disorders, lysozyme immunoreactive cells in NME were fewer than that in GME. Parenchymal infiltration of MAC387-positive cells was common in GME and limited in NME. The number of CD3-positive lymphocytes in the GME lesions tended to be greater than in NME, though the difference was not statistically significant. Morphological and immunohistochemical differences of the lesions, in particular, the characteristics of infiltrative macrophages may reflect these different pathogeneses of the two disorders.     

Effects of intravenous infusion of hypotonic lactated Ringer's solution on calves with diarrhea

The effects of intravenous infusion of hypotonic lactated Ringer's (LR: n=14) on plasma volume and venous blood gases were compared to those of hypotonic Ringer's solutions (RS: n=7) in diarrheic Japanese Black breed calves with metabolic acidosis. Venous blood samples were collected immediately before and after, and at 24 hr after the fluid infusion therapy. The LR and RS infusions increased relative plasma volume to 147.1 +/- 25.5% and 134.2 +/- 18.6%, respectively, just after the fluid therapy. The LR infusion induced an increase in the BE value (+5.1 +/- 4.8 mM) at 24 hr compared to that of RS. LR infusion should be explored as a treatment for dehydration and moderate metabolic acidemia caused by naturally occurring diarrhea in calves.     

Need for flagella for complete virulence of Pseudomonas syringae pv. tabaci: genetic analysis with flagella-defective mutants ?fliC and ?fliD in host tobacco plants

The flagellins purified from Pseudomonas syringae pv. tabaci induce a hypersensitive reaction in nonhost tomato cells. To investigate the role of flagella and flagellin in the compatible interaction, we generated two types of flagella-defective mutant. The fliC mutant lost the fliC gene that encodes flagellin protein, whereas the fliD mutant lost the fliD gene that encodes HAP2-capping protein. The two mutants had markedly reduced ability to cause disease symptoms in tobacco leaves. Furthermore, propagation of the mutants in tobacco leaves was less than that in wild-type pv. tabaci. Compared to the inoculation with wild-type pv. tabaci, inoculation with the two mutants did not markedly induce the expression of typical defense response-related genes such as PAL and hsr203J. Complementation of each fliC and fliD gene to the corresponding deficient mutant restored motility and virulence. These results indicate that flagella of P. syringae pv. tabaci are indispensable organelles for complete virulence on host tobacco plants.     

Cerebellar ataxia due to Toxocara infection in Mongolian gerbils,Meriones unguiculatus

We assessed the usefulness of gerbils as an experimental model for neurologic toxocarosis. Mongolian gerbils, Meriones unguiculatus, infected with Toxocara canis or Toxocara cati (1000 eggs/gerbil) showed progressive neurologic disorders from 50 days after infection in T. canis-infected gerbils or from 120 days after infection in T. cati-infected gerbils. The incidence of the onset was 6 of the 13 gerbils (49%) in the T. canis-gerbils and 5 of the 7 gerbils (71%) in the T. cati-gerbils. Histopathologically, the cerebellum was the most affected in both groups. We observed loss of Purkinje cells, glial nerve fibers, and nerve sheaths. We also found foci consisting of aggregated macrophages scattered in the white matter of the cerebellum. The affected gerbils showed ataxia and ultimately died of cachexia. Our findings suggest that irreversible neurologic toxocarosis in gerbils can be induced by infection with either T. canis or T. cati.     

Phylogenetic Analysis of Field Isolates of Feline Calcivirus (FCV) in Japan by Sequencing Part of Its Capsid Gene

The molecular epidemiology of the infectious disease caused by feline calcivirus (FCV) in Japan was investigated by analysing the phylogenetic relationship among 21 Japanese field isolates, including the F4 strain, and 30 global isolates. Parts of the capsid gene (B–F) of the isolates were amplified by RT-PCR, and the amino acid sequences were compared with those from the global isolates. Thirty-seven and 14 out of a total of 51 isolates were clustered into two distinct genogroups, I and II respectively, by UPGMA and NJ analysis. Seven of the 21 Japanese isolates (33%) fell into group I together with 30 global isolates, while the other 14 Japanese isolates (67%) belonged to group II. The bootstrap repetition analysis of groups I and II formed by the NJ method gave a value of 99.0%. The 14 latter Japanese isolates were clearly separated from the isolates in group I, and they were different from any previously known FCV, forming a new genogroup, which implies that this lineage has been confined to Japan. Comparing the amino acid sequences shared by groups I and II, the amino acid at position 377 in B region was asparagine (Asn or Asp (NH₂)) in group I, while it was lysine (Lys) in all the strains in group II. Similarly, the amino acid at position 539 in the F region was alanine (Ala) or proline (Pro) in group I, while it was valine (Val) in group II; glycine (Gly) at position 557 in group I was serine (Ser) in Group II; and phenylalanine (Phe) or leucine (Leu) at position 566 in genogroup I was tyrosine (Tyr) in group II.     

Concentrations of toxic metals and essential minerals in the mane hair of healthy racing horses and their relation to age

Concentrations of trace elements (As, Al, Pb, Cd, Hg, Se, Si, P, Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Cr, Ni and Mn) in the mane hair obtained from 9 female and 15 male healthy racing Thoroughbred horses aged 2-5 years were analyzed by the inductively coupled plasma atomic emission spectrometry (ICP-AES) method. No significant differences between the female and male horses were observed in the mean concentrations of those minerals. Significantly positive correlations with age were observed in Cd (r=0.546, p<0.01) and Mo (r=0.733, p<0.001). Significantly negative correlations with age were observed in Hg (r= -0.726, p<0.001), Mn (r= -0.450, p<0.05) and Fe (r=-0.642, p<0.01). This reference range of trace elements in the mane hair of racing horses should be used to assess disease and the nutritional status in equine practice.     

Evaluation of cytokine messenger RNA expression in peripheral blood mononuclear cells from dogs with canine demodicosis

Using RT-PCR and semi-quantitative PCR, mRNA expression for canine interferon (IFN)-gamma, interleukin (IL)-2, IL-4, IL-5, IL-10, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta in peripheral blood mononuclear cells (PBMCs) was examined in dogs with or without demodicosis. mRNA expression for IFN-gamma as well as TNF-alpha in dogs with demodicosis (localized (LD) and generalized (GD)) was slightly lower than those in dogs without demodicosis (healthy controls). Expression of IL-5 mRNA in dogs with demodicosis was higher than that in control dogs, but there were no significant differences in IL-4 and IL-10 mRNA expression levels among the three groups. On the other hand, expression levels of TGF-beta mRNA in dogs with GD were higher than those in control dogs and dogs with LD. The expression levels of IL-5 and TGF-beta mRNA decreased in all three dogs with GD which showed resolution of the clinical signs. Taken together, these results suggest that the Th2-like response in PBMCs from dogs with demodicosis is up-regulated, and that subsequent increased expression of IL-5 and TGF-beta mRNA in dogs with GD is reversible after treatment. Therefore, these cytokines, particularly IL-5, might be a useful clinical index of the clinical course in demodicosis. Also, increased TGF-beta mRNA expression might be a key factor for revealing the difference in the mechanism of onset between LD and GD.