The prevalence of antimicrobial-resistant Escherichia coli in two species of invasive alien mammals in Japan

The prevalence of antimicrobial resistance in 128 Escherichia coli isolates was investigated in two species of invasive alien mammals (IAMs): the small Asian mongoose (SAM) and Japanese weasel (JW). The SAM is found on the main island of Okinawa, Japan, where a large number of livestock is available, and the JW is present on a small island, where is isolated from the main island, and have a small number of livestock. We focused on the two IAMs, inhabiting under the different environments, and compared their prevalence of antimicrobial-resistant E. coli. In the comparison of the frequencies of antimicrobial-resistant E. coli isolates between the SAM and JW, JW showed significantly higher prevalence of resistance against three drugs, ampicillin, chlortetracycline and nalidixic acid, compared with SAM's test results (P<0.05). The bla(TEM) gene and the aph1 gene were detected in 35 subjects (91%) of ampicillin-resistant isolates and 6 subjects (100%) of kanamycin-resistant isolates, respectively. The tet (A) gene was detected in 62 subjects (46%) of CTC-resistant isolates, and the tet (B) gene was detected in 25 subjects (8%) of those in IAM. The present results suggest that some IAMs were the carrier of antimicrobial-resistant bacteria and their genes, and the frequencies of these resistances were different between two IAM species.     

The comparison of the collagen fiber contents and hepatic stellate cell distribution in male and female chicken livers

The difference in collagen fiber content, morphological properties and hepatic stellate cell (HSC) distribution was investigated in the liver of both sexes in chicken. Collagen fiber specimens were obtained by maceration treatment with NaOH solution. HSCs were detected using desmin‐specific immunohistochemistry. The ratio of liver weight to body weight was larger in the female than the male chickens. Collagen fiber content, the numerical density of HSCs and the percentage area displaying desmin immunopositivity were not different between the right and left lobes of the liver, in both male and female chickens. However, all of these parameters were larger in the males than the females. In the light microscopic observation, many HSCs in the male had large and elongated cytoplasmic processes. Conversely, HSCs with poorly developed cytoplasmic processes were frequently observed in females. Liver tissue is structurally stronger in male chickens than females and the activity and density of HSCs may be related to the collagen fiber content in chicken liver.     

Lead exposure induces pycnosis and enucleation of peripheral erythrocytes in the domestic fowl

Lead (Pb) shot were administered orally to young chickens to determine the effects on red blood cells (RBCs). The concentrations of Pb in the blood of young chickens rose rapidly after Pb administration and were maintained at high levels for several days. The number of RBCs with pycnotic nuclei, reticulocytes and enucleated RBCs increased concurrently. Pycnotic nuclei were surrounded by enlarged nucleolemmal cisternae, which sometimes opened to the extracellular space. Gel electrophoresis showed that the presence of pycnotic nuclei was not associated with DNA fragmentation typical of apoptosis. It was concluded that exposure to lead shot changes nuclear morphology in the peripheral blood of domestic fowl.     

Hepatic lesions caused by migrating larvae of Ascaris suum in chickens

Group A consisted of chickens infected with a single dose of Ascaris suum and group B of chickens infected with two successive doses. At days 1, 3, 7, 14 and 21 after the first or second infection dose, six chickens from each group were sacrificed. In both groups, larvae were recovered from the livers on days 1, 3, and 7 and lungs on days 3 and 7. No larvae were detected in chickens on day 14. Clear white lesions were noticed only on the livers from chickens of group B at day 7 but had disappeared at day 14. A comparison with group B showed mild histological changes that developed relative to the livers from group A.     

Effect of methotrexate on rostral migratory stream in newborn rats

Two-day-old rats were treated with subcutaneous injections of methotrexate (MTX) 5 mg/kg and 150 mg/kg, and their rostral migratory streams (RMS) were examined time-dependently. MTX treatment increased pyknotic and TUNEL-positive cells and decreased mitotic and phospho-Histone H3-positive cells at almost all time points in the vertical arm, elbow and horizontal arm regions of the RMS. There were more TUNEL-positive cells ratio in the MTX 150 mg/kg group than in the MTX 5 mg/kg group. Treatment with MTX 150 mg/kg decreased the cellularity in the vertical arm region on Postnatal day (PD) 4, but that with the MTX 5 mg/kg did not. TUNEL-positive cells ratio was the highest in the vertical arm region, followed by elbow and horizontal regions in both MTX-treated groups. TUNEL-positive cells ratio in the vertical arm and elbow regions reached their peaks on PD 4 in both MTX-treated groups, and both MTX-treatments significantly decreased Phospho-Histone H3-positive cells ratio on PDs 2.5 and 3 in the vertical arm, elbow and horizontal arm regions. The phospho-Histone H3-positive cells ratio in the vertical arm region recovered on PD4 in the MTX 150 mg/kg group. These findings suggested that RMS required a great amount of folic acid on PD 2 and that the folic acid-requirement differed depending on the anatomical region of the RMS. To our knowledge, this is the first report demonstrating the effect of MTX on the RMS and the necessity of the folic acid metabolism on RMS development in newborn rats.     

Pathological features of hepatic portal venous gas in a cat

An 8-year 8-month-old castrated male Munchkin presented with vomiting, anorexia and hypoactivity. Computed tomography revealed excessive gas accumulation within the intestinal lumen and gas bubbles in the liver, spleen, and portal venous system, indicating hepatic portal venous gas. The cat died without any significant improvement, and mild splenomegaly was found at necropsy. Histologically, multiple gas vacuoles were diffusely observed in the liver and spleen. In the stomach, multiple gas vacuoles and scattered focal ulcers were detected within the mucosa. Multifocal hemorrhage was noted in the small and large intestines, whereas gas vacuoles were not present. Based on these findings, a gastric ulcer under high gas pressure may have provided an entry point for gas into the portal venous system.     

Age-specific plasma biochemistry reference ranges in <1 year old dogs in Japan

The purpose of this study was to investigate and propose possible reference intervals of plasma biochemical analytes in young dogs (<12 months old) in Japan, using 896 canine plasma samples, collected from an array of veterinary clinics throughout the greater Tokyo metropolis area in Japan. The following biochemical parameters were assessed: albumin (ALB), alanine aminotransferase (ALT), alkaline phosphatase (ALP), amylase, aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (CRE), glucose, lipase, total cholesterol (T-Cho), and total protein (TP) were evaluated. Multivariate linear regression analysis indicated that partitioning according to age or gender may be necessary for some plasma analytes. Age appeared to significantly affect ALB, ALT, ALP, BUN, Glucose, Lipase, and Total Protein (P=?<0.001, <0.001, <0.001, 0.013, <0.001, 0.025, and <0.001, respectively). On the other hand, gender significantly influenced ALP, Amylase, Lipase, and T-Cho levels (P=0.017, <0.001, <0.001, and <0.001, respectively) whereas it may be borderline significant with ALT (P=0.072).