Pathogenicity of a new neurotropic equine herpesvirus 9 (gazelle herpesvirus 1) in horses

Pathogenicity of equine herpesvirus 9 (EHV-9), a new type of equine herpesvirus isolated from Gazella thomsoni, in horses was investigated by intranasal inoculation of EHV-9 (10(7) pfu) to two conventionally reared 8-months old half-bred weanling horses. Fever higher than 39 degrees C was recorded. Virus was recovered from nasal swabs and peripheral blood mononuclear cells. Both horses developed neutralizing antibody to EHV-9. Perivascular infiltration of mononuclear cells and glial reaction were found in the olfactory and limbic systems. The results suggested that EHV-9 has a pathogenicity in horses.     

Automated ribotyping, a rapid typing method for analysis of Erysipelothrix spp. strains

Automated ribotyping classified 70 Erysipelothrix species strains, previously classified into 14 RAPD patterns and into 63 PFGE patterns, into 27 ribogroups. Twenty-three strains of the 70 analyzed and classified into 13 ribogroups were previously classified into six ribotypes by the traditional ribotyping method. Moreover, automated ribotyping differentiated seven strains that were not differentiated by PFGE. Therefore, automated ribotyping was more sensitive than RAPD and traditional ribotyping, and it might be a useful method for a rapid screening in epidemiological study of strains of this genus, and more accurate results can be obtained when this method is used together with PFGE.     

Renal lesions in spontaneous insulin-dependent diabetes mellitus in the nonobese diabetic mouse: acute phase of diabetes

The nonobese diabetic mouse is a model of spontaneous insulin-dependent diabetes mellitus. The present study made longitudinal observations of renal lesions in the acute-progressive phase of diabetic mice 0, 10, 20, 30, and 40 days after onset of diabetes without insulin therapy. Plasma creatinine and blood urea nitrogen concentrations gradually increased after onset of diabetes. Kidney weight increased and plateaued at day 20. Under electron microscopy the glomeruli demonstrated only mild changes on day 40. In the proximal tubules proliferating cell nuclear antigen-positive nuclei and nuclear divisions were increased on days 10 and 20. On day 40 of diabetes, increased periodic acid-Schiff-positive granules, confirmed as lysosomal dense bodies, increased neuronal nitric oxide synthase (nNOS) positive reaction, and decreased periodic acid-Schiff staining in the brush border were observed in the proximal straight tubules. In the juxtaglomerular apparatus stratified macula densa were decreased with time in diabetes compared with the findings on day 0, and this macula densa positively reacted with nNOS. No changes in renin levels were observed. In addition, apoptotic cells were not detected. In conclusion, this research represents the first thorough characterization of acute changes in nonobese diabetic mouse kidneys. The results demonstrated renal hypertrophy and slight glomerular injury in early stages and structural alteration of the proximal straight tubules at later stages during the acute phase of diabetes. Furthermore, increased nNOS may represent one of the pathogenic factors of diabetic nephropathy.     

Differential expression of neurofilament 200-like immunoreactivity in the main olfactory and vomeronasal systems of the Japanese newt, Cynops pyrrhogaster

Expression of neurofilament 200 (NF200)-like immunoreactivity was examined in the main olfactory system and the vomeronasal system of the Japanese newt, Cynops pyrrhogaster, using anti-porcine NF200 monoclonal antibody (clone N52) to investigate the differences in phenotypical characteristics between these systems. The entire nasal cavity was a flattened single chamber consisting of the main nasal chamber (MNC) and the lateral nasal sinus (LNS) communicating with each other. The olfactory epithelium (OE) was present in the MNC, and the vomeronasal epithelium (VNE) was in the LNS. The OE possessed only a small number of NF200-like immunoreactive receptor neurons. The olfactory nerve and the olfactory nerve layer of the main olfactory bulb also contained a small number of NF200-like immunoreactive axons. In contrast, the VNE possessed many NF200-like immunoreactive receptor neurons. The vomeronasal nerve and the vomeronasal nerve layer of the accessory olfactory bulb contained many NF200-like immunoreactive axons. These findings in the Japanese newt indicate that NF200-like immunoreactive receptor neurons constitute a major subpopulation in the VNE and a minor subpopulation in the OE. In addition, NF200-like immunoreactivity seems to be a useful marker to distinguish the vomeronasal system from the other nervous systems including the main olfactory system in the Japanese newt. The localization of a few NF200-like immunoreactive receptor neurons in the OE might indicate that pheromone-sensitive receptor neurons are intermingled in the OE of the Japanese newt.     

Distribution of type VI collagen in the cartilaginous tissue of the proximal tibia in the domestic cat

To investigate the distribution of the early stage chondrocytes during the formation and closure of epiphyseal growth plate (EGP) of the domestic cat, we examined the EGP of proximal tibiae by immunohistochemistry for type VI collagen. In the epiphyseal cartilage without the secondary ossification center (SOC) and EGP in newborn cats aged 1 and 10 days, type VI collagen-positive chondrocytes were located around the cartilage canals and articular surface. In the epiphyseal cartilage with the SOC and EGP in young cats aged 1 to 3 months, type VI collagen-positive chondrocytes were located in the upper resting zone of the EGP, and then increased throughout the resting zone along with maturation. In the adult cats with the partially closed EGP, type VI collagen-positive chondrocytes were distributed throughout the remaining EGP. These findings indicate that the early stage chondrocytes characterized with type VI collagen are continuously located in the EGP during maturation. In addition, the increase of the early stage chondrocytes and the decrease of the reserve chondrocytes in the EGP along with maturation may cause the cessation of the longitudinal growth of the EGP, and finally bring about the EGP closure.     

Imaging of the lectin-labeled cell surface of human lymphocytes by the use of atomic force microscope

The atomic force microscope (AFM) is a new useful tool to examine the surface structure of specimens with a higher resolution than the conventional scanning electron microscope. In the present study, we used the AFM to observe the surface of paraformaldehyde-fixed human lymphocytes processed for histochemistry using a biotinylated lectin, wheat germ agglutinin, followed by colloidal gold and silver-enhancement method. Before the treatment, no particles were attached to the cell surface. After treatment, many particles about 100 to 150 nm in diameter were visualized on it. Since we could observe the same cells on the slide glass before and after treatment, the AFM has the advantage to enable us the repeated imaging of samples treated with various kinds of histochemistries.     

Detection of a quantitative trait locus for intramuscular fat accumulation using the OLETF rat

The Otsuka Long-Evans Tokushima Fatty (OLETF) rat is an animal model for obese type 2 diabetes. We showed that the OLETF rat exhibits higher levels of intramuscular fat content in Musculus longissimus as compared to the Fischer-344 (F344) rat. Our investigation was designed to identify quantitative trait loci (QTLs) contributing to the increased levels of intramuscular fat content by performing a whole-genome search using 108 F2 intercross obtained by mating the OLETF and the F344 rats. We identified one QTL responsible for intramuscular fat accumulation on rat chromosome 1 with a maximum lod score of 3.4, which accounts for 5% of the total variance. As expected, the OLETF allele corresponds to the increased levels of intramuscular fat content.     

Immunocytochemical and morphometric studies on the pars distalis of the golden hamster from perinatal to senile stage

Six cell types of the pars distalis were studied from perinatal to senile stage in the golden hamster in combination with morphometric analysis and immunocytochemistry. GH cells occupied only a small area at 15 days of gestation and increased remarkably after birth to occupy a significantly larger area in the young adult than that in the other stages. PRL cells first appeared at 3 days after birth and increased rapidly thereafter to be distributed throughout the pars distalis. They always occupied a larger area in females than in males from 3 weeks after birth onward. ACTH cells were distributed mainly in the peripheral region of the pars distalis. They were dominant at 15 days of gestation, but relatively decreased after birth. The gonadotrophic cells were divided into LH cells and FSH cells. About 70% of LH cells were also immunoreactive to anti-FSH serum. LH cells occupied a larger area than that of FSH cells in every stage examined. TSH cells occupied the second largest area at 15 days of gestation, but rapidly decreased at 3 weeks after birth to occupy the smallest area among the immunoreactive cell types throughout the life-span. The chronological changes in the percentages of all cell types constituting the pars distalis seemed to reflect the activity of these cell types at a given stage.     

Enzyme histochemistry of the olfactory and vomeronasal sensory epithelia in the golden hamster.

Histochemical activities of several enzymes were investigated in the olfactory epithelium (OE) and vomeronasal organ (VNO) of the golden hamster. Activities of adenosine triphosphatase, lactate dehydrogenase and succinate dehydrogenase were intense in the OE, and the sensory (VSE) and respiratory epithelium (VRE) of the VNO. The activity of acid phosphatase was intense in both the OE and the VSE, while that of non-specific esterase was intense in the VSE alone. The activity of alkaline phosphatase was detectable only in the VRE. Activities of monoamine oxidase and acetylcholine esterase were negative in all of the OE, VSE and VRE. These similarities and differences in the histochemical distribution of enzymes between OE and VSE may reflect the common olfactory function and/or functional specialization in these epithelia. On the other hand, the VRE was considerably different from the OE and VSE in the enzymatic distribution. This may reflect the non-olfactory function of this epithelium.     

Effects of correcting missing daily feed intake values on the genetic parameters and estimated breeding values for feeding traits in pigs

Daily feed intake (DFI) is an important consideration for improving feed efficiency, but measurements using electronic feeder systems contain many missing and incorrect values. Therefore, we evaluated three methods for correcting missing DFI data (quadratic, orthogonal polynomial, and locally weighted (Loess) regression equations) and assessed the effects of these missing values on the genetic parameters and the estimated breeding values (EBV) for feeding traits. DFI records were obtained from 1622 Duroc pigs, comprising 902 individuals without missing DFI and 720 individuals with missing DFI. The Loess equation was the most suitable method for correcting the missing DFI values in 5–50% randomly deleted datasets among the three equations. Both variance components and heritability for the average DFI (ADFI) did not change because of the missing DFI proportion and Loess correction. In terms of rank correlation and information criteria, Loess correction improved the accuracy of EBV for ADFI compared to randomly deleted cases. These findings indicate that the Loess equation is useful for correcting missing DFI values for individual pigs and that the correction of missing DFI values could be effective for the estimation of breeding values and genetic improvement using EBV for feeding traits.