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 alpha-pinene odor in different concentrations on stress-induced hyperthermia in rats

Stress-induced hyperthermia is observed in animals exposed to stressful conditions. In our previous study, plant-derived fragrances such as green odor and alpha-pinene were shown to suppress this stress response in rats. In the present study, we examined the concentration-dependence of the alpha-pinene effects on stress-induced hyperthermia. Male rats carrying telemetry transmitters were transferred individually to a new cage containing bedding that had been sprayed with 0.3, 0.03, and 0.003% concentrations of alpha-pinene or control solvent. Following transfer to the novel environment, the body temperature increased significantly, and this response was clearly suppressed when the cage was scattered with 0.03% alpha-pinene only. These results suggest that the effect of alpha-pinene on stress-induced hyperthermia can be observed only at a certain concentration.     

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.     

Substances derived from 4-ethyl octanoic acid account for primer pheromone activity for the "male effect" in goats

A major constituent of the characteristic "goaty odor" 4-ethyl octanoic acid (4EOA) was previously shown to have no primer pheromone activity. This was also confirmed by our own bioassay system utilizing the recording technique of neural activity of the hypothalamic gonadotropin-releasing hormone pulse generator in goats. However, when the synthetic 4EOA solution was kept at room temperature for several months, primer pheromone activity appeared in the same solution. Headspace gas chromatography/mass spectrometry analysis revealed that there were several newly formed substances in addition to 4EOA samples with primer pheromone activity. These results suggest that 4EOA derived substance(s) but not 4EOA itself is(are) primer pheromone in goats.     

Modulation of sodium channels by the oxadiazine insecticide indoxacarb and its N-decarbomethoxylated metabolite in rat dorsal root ganglion neurons

The effects of the oxadiazine insecticide indoxacarb and its N-decarbomethoxylated metabolite (DCJW) on tetrodotoxin-resistant (TTX-R) voltage-gated sodium channels in rat dorsal ganglion neurons were studied using the whole-cell patch clamp technique. Indoxacarb and DCJW suppressed the peak amplitude of action potentials, and DCJW exhibited a faster time course and higher potency than indoxacarb in the blocking effects. In voltage-clamp experiments, indoxacarb and DCJW suppressed TTX-R sodium currents in a time-dependent manner without a steady-state level of suppression. IC50 values for indoxacarb and DCJW on TTX-R sodium currents were estimated to be 10.7 and 0.8 microM after 25 min of bath application, respectively. DCJW was about 10 times more potent than indoxacarb in blocking TTX-R sodium currents. Although the suppressive effects of indoxacarb were partially reversible after washout with drug-free external solution, no recovery of sodium current was observed in DCJW treated neurons after prolonged washout. In current-voltage relationships, both indoxacarb and DCJW blocked the sodium currents to the same degree in the entire range of membrane potentials. The sodium conductance-voltage curve was not shifted along the voltage axis by indoxacarb and DCJW at 10 microM. In contrast, the steady-state inactivation curves were shifted in the hyperpolarizing direction by indoxacarb as well as by DCJW. Based on these results, it was concluded that indoxacarb and DCJW potently blocked the TTX-R sodium channel in rat DRG neurons with hyperpolarizing shifts of the steady-state inactivation curves, suggesting preferential association of the insecticides to the inactivated state of sodium channels. The small structural variation between indoxacarb and DCJW resulted in clear differences in potency for blocking sodium channels and reversibility after washout.