Previous studies have shown that the dilating effect of nitric oxide (NO) on the fetal ductus arteriosus (DA) is age dependent and more marked in the premature stages in rats, but the factors that mediate this effect are poorly understood. The purpose of this study is to determine the changes in the expression of NO synthase (NOS) mRNA in the fetal DA and to examine the effect of an 11-β-hydroxylase inhibitor of corticosterone synthesis, namely, metyrapone, on NOS expression. NOS 3 mRNA expression was observed in 17.5-day-old rat fetuses; thereafter, its level significantly increased and reached its peak on day 19.5 and then decreased until the end of the gestation period (day 21.5). To inhibit corticosterone synthesis, a constant infusion of metyrapone was administered to rats; this significantly decreased the fetal plasma corticosterone concentration as well as NOS 3 mRNA expression in the DA in a time-dependent manner. These results indicate that NO is generated by NOS 3 in the DA and that the age-dependant expression of NOS 3 in the premature DA is attributable to corticosterone-associated activity.

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Ionizing radiation suppresses neurogenesis in the mammalian brain. This in vitro study compared the detrimental effect of acute gamma-irradiation on immature hippocampal cells with mature cells. Both rat immature (0.5 day in vitro (DIV)) and mature hippocampal cells (14 DIV) were irradiated with 0-4 Gy gamma-rays. Cell viability was analyzed by using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay. DNA fragmentation study was performed by extracting intracellular DNA. Morphological features of apoptosis were characterized by 4',6-diamidine-2'-phenylindole, dihydrochloride (DAPI) staining. MTT assay revealed that the survival rate of immature hippocampal cells declined in a dose-dependent manner within the range of irradiation applied, but was not changed in mature cells. Intranucleosomal DNA fragmentation in a ladder like pattern was dose-dependently increased in immature cells, but not in mature cells. The number of apoptotic nuclei in immature cells increased significantly in a dose-dependent manner within the range of irradiation applied. Active caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP) expressions in immature hippocampal cells at 6 hr after 2 Gy exposure were markedly higher than control levels. The significantly greater radiosensitivity of immature hippocampal cells than that of the mature cells, indicates that the susceptibility of such hippocampal cells depends on their maturation. In addition, gamma-irradiation may induce caspase-dependent apoptosis in immature hippocampal cells.

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Shiga toxin-producing Escherichia coli (STEC) isolated from Japan were investigated for the distribution of virulence genes. A total of 232 STEC strains including 171 from cattle and 61 from human were examined for the occurrence of genes responsible for bacterial adhesions to intestine, e.g., eae (intimin, E. coli attaching and effacing), saa (STEC autoagglutinating adhesin), iha (irgA homologue adhesin), efa1 (E. coli factor for adherence), lpfA_O113 (long polar fimbriae), and ehaA (EHEC autotransporter) by colony hybridization assay. Similarly, the presence of toxigenic cdt (cytolethal distending toxin), and subAB (subtilase cytotoxin) genes were also checked. Among cattle isolates, 170, 163, 161, 155, 112 and 84 were positive for lpfA_O113 (99%), ehaA (95%), iha (94%), saa (91%), subAB (65%), and cdt-V (49%), respectively, while 2 were positive for eae (1.2%) and efa1 (1.2%) each. In case of human isolates, 60, 59, 58 and 58 were positive for ehaA (98%), iha (97%), efa1 (95%), and eae (95%), respectively, while 11, 2, 2, and 1 were positive for lpfA_O113 (18%), saa (3.3%), cdt-V (3.3%), and subAB (1.6%), respectively. Therefore, in human STEC isolates efa1 and eae whereas in cattle isolates saa, lpfA_O113, cdt-V and subAB were prevalent. These data indicate differential occurrence of some pathogenic genes in human and cattle originated STEC strains in Japan.

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A total of 176 E. coli isolates were retrieved from 203 diarrheic fecal samples collected from Korean cattle on 117 different farms. The most frequently observed resistance in E. coli isolates was to tetracycline (88.6%), followed by streptomycin (80.7%) and ampicillin (64.8%). Resistance to cefazolin, cefoperazone, cefepime and amikacin was very low. Of the 176 E. coli strains, forty (22.7%) isolates from 30 farms showed resistance to fluoroquinolones (FQ). All the FQ-resistant strains possessed double mutations at codons 83 and 87 in the gyrA gene, and a single mutation mostly at codon 80 in the parC gene, except in one isolate. The pulsed-field gel electrophoresis profiles of the FQ-resistant E. coli isolates were heterogeneous, but two or three isolates that showed an identical pattern originated from the same or different farms. This study demonstrates that FQ resistance is frequently observed in E. coli from diarrheic cattle and that mutations in the quinolone resistance-determining region are the same as those seen in E. coli originating from other animal species and humans. The FQ resistance in diarrheic cattle might have been mostly acquired independently, although the possibility of transmission of FQ-resistant E. coli within a farm or between farms is plausible.

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We have previously reported the action of whey acidic protein (WAP) inhibiting the proliferation of mouse mammary epithelial cells in the experiments utilizing in vivo and in vitro systems. We report herein the bacteriostatic activity of WAP. Western blot analysis demonstrated successful isolation of WAP from whey fractions of rat milk by column chromatography. The WAP fraction inhibited the growth of Staphylococcus aureus JCM2413 in a dose-dependent manner, but did not inhibit the growth of Escherichia coli. The bacteriostatic activity of WAP was highest at pH 6.6 and was not affected by the presence of 150 mM NaCl. A scanning electron micrograph of bacteria treated with WAP exhibited the disruption of the bacterial cell walls.

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A case of Staphylococcus aureus intramammary infection (IMI) on a Japanese dairy farm was monitored for 9 months. S. aureus isolates from cows and environmental samples consisted of specific strains with sequence types 352 and 705, as determined by multilocus sequence typing. Clonal strains of these sequence types are isolated from cows worldwide, indicating that they are adapted to the bovine environment. These results explain why many IMI cases are persistent and lead to subclinical mastitis. The strain isolated from milk was identical to those isolated from the cows' bodies and cows carrying S. aureus, milking units, personnel, heifers and cats in the dairy barn. These locations and factors should be emphasized as sources and routes of strains causing IMI.

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A cps-based multiplex PCR for typing of Actinobacillus pleuropneumoniae serotypes 1, 2 and 5 was developed. This method should be specific and practical in Japan where more than 88% of isolates are serotypes 1, 2 or 5.

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The width and area of the ciliary cleft (CCW and CCA) according to ultrasound biomicroscopy was rectified to compare dogs of different body sizes/weights, including toy breed (TBG), small breed (SBG), medium breed (MBG) and large/giant breed groups (LGBG). A linear correlation was detected between the natural log of body weight and the ocular axial length (OAL) reflecting the ocular size (OS; r=0.81, p<0.001). A significant positive correlation was found between OAL and the distance of the Schwalbe's line to the anterior lenticular capsule (SLD; r=0.87, p<0.001), suggesting that SLD could rectify canine OS. Rectified CCW (r-CCW) and CCA (r-CCA) were calculated using SLD and fixed SLD as the SLD mean (SLDM). The SLDM was 2.55 mm in this study, and r-CCW and r-CCA were calculated as r-CCW = CCW × (2.55/SLD) and r-CCA = CCA × (2.55/SLD)². The CCW values of TBG, SBG and MBG were narrower than those of LGBG (p<0.05). There were significant statistical differences in CCA between all groups other than TBG and SBG (p<0.05). There were no significant differences in r-CCW and r-CCA in any of the groups. In addition, CCW/SLD did not show significant changes in dogs with different body sizes/weights. These results suggested that r-CCW, r-CCA and CCW/SLD can be used for comparison between dogs of different body sizes/weights.

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An 8-year-old miniature dachshund presented with a right femoral muscle mass and anorexia. Cytology of the mass revealed a number of small-sized lymphoid cells containing a pleomorphic-shaped dense nucleus and narrow pale cytoplasm. Histopathology indicated that neoplastic lymphoid cells proliferated in skeletal muscles and replaced the muscular architecture. Immunohistochemical and genetic examinations confirmed the diagnosis of primary skeletal muscle lymphoma classified as the pleomorphic small cell type and T-cell low-grade. Although the dog suffered at least three relapses by combination chemotherapy, the dog survived 713 days after the initial presentation.

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Guide dogs for the blind help blind people physically and mentally in their daily lives. Their qualifications are based on health, working performance and temperament; approximately 70% of dogs that fail to qualify are disqualified for behavioral reasons. In order to achieve early prediction of qualification, it would be essential as the first step to identify important temperament traits for guide dogs. Therefore, we administered a questionnaire consisting of 22 temperament items to experienced trainers to assess candidate dogs at the Japan Guide Dog Association after three months of training, which was at least three months prior to the final success (qualified as a guide dog) or failure (disqualified for behavioral reasons) judgment. Factor analyses of question items stably extracted three factors with high internal consistency, Distraction, Sensitivity and Docility. When we compared factor points between successful dogs and failed dogs, the successful dogs showed significantly and consistently lower Distraction points and higher Docility points. Additionally, Distraction points could predict qualification with 80.6% accuracy and detect 28.2% of the failed dogs that had higher Distraction points than any of the successful dogs. Of the nine question items not included in the three factors, two items (`Aggression' and `Animal interest') were consistently associated with qualification. These results suggest that Distraction is stably assessable and has the strongest impact on success or failure judgment; therefore, it will be the first target to establish a behavioral test that may lead to early prediction of guide dog qualification.

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A healthy pig shows significant eosinophil infiltration in the lamina propria of the small intestine. Although the exact role of these infiltrated eosinophils in healthy pigs is unclear, eosinophil infiltration is a well-known phenomenon that is frequently observed during an allergic status. Alpha-linked galactooligosaccharide (GOS) reduces eosinophil infiltration into broncho-alveolar lavage fluid of an allergic airway eosinophilia model. We evaluated the effect of GOS oral administration on the suppression of eosinophil infiltration in the small intestine of healthy weaned pigs. Nine 21-day-old pigs were purchased and divided into three groups. One group was fed the basal diet supplemented with sucrose at 0.11% (C), one group was fed the basal diet supplemented with GOS at 1.17% (GOS A) and one group was fed the basal diet supplemented with GOS at 0.03% (GOS B). Each group was fed its respective diet throughout this study (10 days). The daily body weight gain from d3 to d10 was significantly bigger in the GOS B group than in the other groups. The feed conversion ratios from d0 to d10 were two times lower in the GOS B group than in the C group. Dietary GOS suppressed eosinophil infiltration in the small intestine. However, GOS administration had no effect on the organic acid level or microbial composition in the small and large intestinal digesta.

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In management of canine cardiac disorders, cardiac drugs are commonly administered with food, although the cardiovascular effects of feeding and frequency of feeding are unknown. This study investigated the cardiovascular effect of feeding and frequency of feeding using a telemetry monitoring system in unanesthetized and unrestrained dogs. Systolic and diastolic blood pressure, heart rate and double product were steeply elevated during the five minutes immediately before feeding. They showed a sharp fall within 60 min after feeding time, especially the systolic and diastolic blood pressure, which showed lower values than from before feeding time. There were no significant differences in the means of preprandial elevation, postprandial fall or 24-hr averages in the once- and twice-daily feeding periods.

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Although anesthetic agents are known to affect cerebral metabolism, pentobarbital and ketamine have been widely used for animal imaging studies. The purpose of this study is to evaluate alterations in striatum metabolites in dogs between anesthetized with pentobarbital and with ketamine in proton magnetic resonance spectroscopy (¹H-MRS). ¹H-MRS was performed to ten healthy adult beagle dogs (9-11 kg) at a field strength of 3 T in order to identify metabolic changes after pentobarbital or ketamine administration in the striatum in vivo. Ten dogs were divided into 2 groups as follows: 5 as the pentobarbital-administered group (P group) and 5 as the ketamine-administered group (K group). We found that levels of Glx of the P group was significantly lower than that of the K group (6.90 ± 0.99 (SD) vs 9.77 ± 1.14 in 5 dogs, p= 0.003). In addition, the P group also has lower levels of Cr (6.29 ± 0.44 vs 7.89 ± 0.91 in 5 dogs, p=0.009) and NAA (5.02 ± 0.65 vs 6.45 ± 1.13 in 5 dogs, p=0.041) compared to the K group. However, there were no significant difference between the P group and the K group in striatal levels of Cho and Ins (p>0.1). We demonstrated that MRS-measured metabolites in the specific regions of the brain can be influenced by anesthetic agents.

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Although the actions of cysteine proteases are controlled in part by endogenous tight-binding cysteine protease inhibitors from the cystatin superfamily, regulatory mechanisms used by ticks to control protease activities are unknown. We report here the interaction of 2 endogenous midgut cysteine protease inhibitors, Hlcyst-1 and Hlcyst-2, with an endogenous midgut cysteine protease, HlCPL-A in Haemaphysalis longicornis. In vitro inhibition assays demonstrated that the hydrolytic activity of HlCPL-A was inhibited by Hlcyst-1 and Hlcyst-2 in dose dependent manner. Immunofluorescent studies revealed that Hlcyst-1 and Hlcyst-2 are co-localized with HlCPL-A in the epithelial cells of the midgut. The hemoglobin degradation activity of HlCPL-A was dose-dependently inhibited by Hlcyst-1 and Hlcyst-2. These results strongly indicate that, Hlcyst-1 and Hlcyst-2 are possible inhibitor of HlCPL-A and play a key role in regulatory mechanisms of hemoglobin degradation process in ticks.

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Leiomyosarcoma in soft tissue has only been reported in humans or animals. We performed pathological examination of a 3-years-old male squirrel monkey which had a large mass in the right axilla. The mass in the right axilla was surgically resected but it soon reoccurred. This tumor was diagnosed as a leiomyosarcoma based on histopathology and immunohistochemistry using the expression of α-smooth muscle actin and desmin. Leiomyosarcoma in squirrel monkey has been reported in one case, there was no reoccurrence or metastasis. Most of the reported tumors in nonhuman primates have occurred in aged monkeys. This case was a rare tumor considering the young age of the animal.

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Senile systemic amyloidosis (SSA) is a rather common disease in elderly people, but it is very rare in animals, including nonhuman primates. Pathological examination of a 26-year-old male savannah monkey (Cercopithecus aethiops) revealed systemic amyloidosis with severe cardiac fibrosis, and tenosynovial degeneration of the elbow and knee joints. The amyloid deposits were observed predominantly in the heart, lung, intestine and tenosynovium, and were positive for transthyretin (TTR) in immunohistochemistry. Immunohistochemical results, together with the distribution of the amyloid deposited lesions and the age of the monkey, were equivalent to those of human SSA. This is the second case of animal SSA with unprecedented TTR amyloid deposited lesions of the tenosynovium resembling human SSA. There may be a genetic factor that makes this species susceptible to SSA, since SSA has been reported in no other mammal besides humans.

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Leydig cell tumors with spindle-shaped cells are very rare in humans and animals. We report that an 84-week-old male CD-1 mouse had a malignant Leydig cell tumor characterized by proliferation of oval to spindle-shaped cells with or without fat deposition, and with a storiform pattern. These cells were immunopositive for inhibin and S-100, and negative for the androgen receptor, thereby suggesting that they may have differentiated from Leydig cells. This differentiation from Leydig cells was further confirmed by the immunopositivity of these cells for nestin and α-smooth muscle actin, both of which are known to be expressed in the stem/progenitor cells that differentiate into Leydig cells. These findings suggest that the tumor is most probably a malignant spindle-cell-type Leydig cell tumor.

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Fifty-two canine and eighteen feline primary pulmonary carcinomas were evaluated immunohistochemically for the expression of proteins associated with multidrug resistance to anti-cancer drugs. P-glycoprotein (PGP), multidrug resistance-related protein (MRP) and lung resistance-related protein (LRP) expression were frequently observed in neoplastic cells of all carcinoma types, and metallothionein (MT) expression was observed in about half of each carcinoma type. Furthermore, overlapping expression was detected in all positive cases. These results indicate that most canine and feline primary pulmonary carcinomas may have strong multidrug resistance, which is related to the PGP, MRP, LRP or MT expression. It might be difficult to treat canine and feline primary pulmonary carcinomas using anti-cancer drugs because of multidrug resistance.

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We report here a case of hepatic myelolipoma with systemic amyloidosis in a goose (Anser cygnoides domesticus), which died suddenly following the short history of weakness and greenish diarrhea. At necropsy, multiple yellowish-white foci were observed on the surface of the prominently enlarged liver. Histologically, there were multiple foci of adipose tissue admixed with myeloid elements in various proportions in the liver as well as amyloid deposition in several organs including the liver, intestine, spleen, kidney, and ovary. Ultrastructurally, erythroblast-like cells and myelocytes, which showed various stages of differentiation, were observed in the foci of the liver. These findings shared characteristics of hepatic myelolipoma which is very rare in birds.

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The determination of antimicrobial minimum inhibitory concentration (MIC) in Erysipelothrix rhusiopathiae by using the agar dilution method has not been covered by the Clinical and Laboratory Institute (CLSI). Only the broth microdilution method has been outlined. This report describes a modification of the agar dilution procedure for E. rhusiopathiae using Trypto-soy agar supplemented with 0.1% Tween 80 and incubation in ambient air at 37°C for 24 hr. The MICs of the assay were in agreement with those of the broth microdilution method recommended by the CLSI. Antimicrobial susceptibility test was performed using this method for 149 E. rhusiopathiae isolates from 2 meat processing plants in Kagoshima Prefecture during the period of April 2004 to March 2005. The number of strains resistant to oxytetracycline, erythromycin, lincomycin, ofloxacin and enrofloxacin were 56 (37.6%), 4 (2.7%), 18 (12.1%), 21 (14.1%) and 19 (12.8%), respectively. All strains were susceptible to ampicillin.

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Performing magnetic resonance imaging (MRI) in patients with a metallic implant raises concern over the potential complications, including susceptibility artifacts, implant migration, and heat injury. The purpose of this study was to investigate these complications in dogs with implanted microchips by evaluating MR images and the histopathological changes after 1.5 Tesla (T) MRI. Five dogs underwent microchip implantation in the cervicothoracic area. One month later, the area was imaged using 1.5T MRI in three dogs. The microchips were removed surgically together with the surrounding tissue in all dogs. There was significant signal loss and image distortion over a wide range around the area where the microchip was implanted. This change was consistent with susceptibility artifacts, which rendered the affected area including the spinal cord undiagnostic. The artifact was more extensive in T2*-weighted images (gradient-echo) and less extensive in proton density-weighted images (fast spin-echo with short echo time). Histopathologically, all microchips were well-encapsulated with granulation tissue, and there were no evidence of migration of microchips. Cell debris and a moderate number of degenerated cells with fibrin were seen in the inner layer of the granulation tissue in each dog that underwent MRI. These changes were very subtle and did not seem to be clinically significant. The results of this study suggest that, in 1.5T MRI, susceptibility artifacts produced by implanted microchips can be marked, although the dogs with implants appeared to be scanned safely.

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In order to improve the reproductive performance during the summer period, embryo transfer (ET; Japanese black embryo) following artificial insemination (AI; Holstein semen: ETFAI) was conducted in dairy cows in south-western Japan (n=56). The conception rate was improved in cows with ETFAI compared with conventional AI, which served as the control (n=195; 30.4% vs. 13.8%, P<0.01). However, higher fetal loss was observed in ETFAI compared with the controls (38.1% vs. 7.4%, P<0.05). Four cases of twin pregnancy resulted in 2 singletons and a set of twins. There was no difference in the plasma progesterone level on d0 or d7 (d0=AI), but rather lower rectal temperature was observed on d7 or d8 (38.7°C vs. 39.4°C and 38.8°C vs. 39.1 °C, P<0.05) in pregnant cows compared with those that were open. ETFAI could improve reproductive performance in dairy cows during the summer period in south-western Japan.

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The objective of this study was to investigate and characterize the metabolic activities of CYP1A in deer, cattle and horses in comparison to those of rats using ethoxyresorufin O-deethylation (EROD) and methoxyresorufin O-demethylation (MROD) assays. We performed an inhibition study for these activities using anti-rat CYP1A1 antibody and identified that these activities were due to the CYP1A subfamily. Interspecies differences in the CYP1A-dependent activities were highly observed in this study. In particular, we found that the horse had the highest EROD and MROD activities among the examined animal species. In the kinetic analysis, the horses showed the highest Vmax and catalytic efficiency (Vmax/Km), followed by the cattle, deer and rats.

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To ascertain the clinicopathological process underlying dysglycemia induced by the fluoroquinolone antibacterial gatifloxacin (GFLX), we orally administered 100 or 300 mg/kg/day to male clinically healthy (naive) or spontaneous type II (diabetic) Goto-Kakizaki rats for 15 days (days 1 to 15). Treatment of naive rats with GFLX led to decreased blood glucose concentrations at 100 mg/kg/day on day 1. In diabetic animals, markedly increased blood glucose concentrations were noted from 100 mg/kg/day on day 3, and all of the animals given 300 mg/kg/day died or were killed because of moribund conditions by day 9. In a glucose tolerance test, serum insulin concentrations decreased significantly in naive rats receiving 300 mg/kg/day. Microscopically, cytoplasmic vacuolations of the pancreatic islets were observed in naive rats receiving 300 mg/kg/day, and congestion and/or hemorrhage were additionally noted in diabetic rats given 100 mg/kg/day or more. In toxicokinetics with 100 mg/kg/day, AUC_{0-8 hr} values for GFLX were higher in diabetic rats than in naive rats, and relatively high serum GFLX concentrations at 8 hr post-dose and extraordinarily high pancreatic GFLX concentrations were also observed in diabetic rats. These results demonstrate that hypoglycemia or hyperglycemia induced by GFLX is associated with higher distribution and retention of GFLX in the pancreas, leading to disturbed insulin secretion.

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Psittacine beak and feather disease (PBFD), which is caused by beak and feather disease virus (BFDV), has been reported in a wide range of psittacine species, except the cockatiel (Nymphicus hollandicus), in which PBFD has rarely been reported. We detected BFDV from a case of PBFD in a cockatiel in the present study. The virus was designated CO-JA. The whole genome sequence of CO-JA had from 86 to 98% homology with BFDVs in psittacine species. CO-JA clustered with isolates derived from other cockatoos in phylogenetic analyses based on two major virus proteins. We concluded that genetic data cannot explain the reason why PBFD is rarely found in the cockatiel.

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The Betsukai town office implemented bovine viral diarrhea virus (BVDV) preventive activities (i.e., vaccination and surveillance) in 2006. Using bulk tank milk screening followed by individual blood tests using a Reverse Transcription-Polymerase Chain Reaction (RT-PCR) method, persistent infection (PI) cattle were detected and eliminated from the population. Based on data for PI cattle detected between 2006 and 2007, we conducted a case control study to find risk factors associated with the presence of PI cattle. Significantly associated farm level factors for increasing risk of producing PI cattle include; 1) no recent purchase of cattle (between 2004 and 2007) and 2) no prevention of people/animals entering the premises. This study suggests that not only vertical transmission from dam to calf but also indirect contact with people and animals play an important role in transmitting BVDV infection and subsequent production of PI animals.

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