Toshihiro Ichijo

Comparison of renal biomarkers with glomerular filtration rate in susceptibility to the detection of gentamicin-induced acute kidney injury in dogs.

Fourteen renal biomarkers were compared with measurement of glomerular filtration rate (GFR) in detecting acute kidney injury (AKI) in beagle dogs given gentamicin (40 mg/kg/day by subcutaneous injection) for 7 consecutive days. Serum and urinary biomarkers were measured before administration of gentamicin and then on days 4 and 8 after starting administration. GFR was derived by use of a simplified equation. Increased urinary cystatin C and decreased GFR occurred from day 4 and were detected before increases in blood urea nitrogen (BUN) and serum creatinine concentrations and changes in other urinary parameters. The closest correlation was between urinary cystatin C and GFR. At termination, microscopical examination revealed extensive necrosis of proximal tubular epithelium with hyaline casts in the kidney of treated dogs. These data indicate that urinary cystatin C is the most sensitive index of kidney injury and GFR reflects the kidney functional mass.

Effects of Dietary Forage and Calf Starter Diet on Ruminal pH and Bacteria in Holstein Calves during Weaning Transition

We investigated the relationship between ruminal pH and bacteria in calves fed calf starter with and without forage during weaning transition. First, 16 Holstein bull calves were obtained from dairy farms and equipped with rumen cannulas by cannulation surgery. Then, calves (73.5 ± 4.2 kg; mean ± SE) were assigned to groups fed calf starter either with forage (HAY, n = 8) or without forage (CON, n = 8), and all calves were weaned at 8 weeks of age. Ruminal pH was measured continuously, and rumen fluid samples were collected at 7, 8, 9, and 11 weeks of age, namely −1, 0, 1, and 3 weeks after weaning, respectively, to assess volatile fatty acid concentrations and bacterial DNA. The 24-h mean ruminal pH was significantly (P < 0.05) different between the two groups. Diurnal changes in the 1-h mean ruminal pH were observed throughout the study in the HAY group; however, they were not observed at 0 and 1 weeks after weaning in the CON group. Moreover, the HAY group had significantly (P < 0.05) higher proportions of acetate and butyrate and lower proportion of propionate, and significantly (P < 0.05) lower ruminal acetate-to-propionate ratios were observed in the CON group. The ruminal bacterial diversity indices decreased after −1 week in both groups and increased at 0 and 1 weeks after weaning in the HAY and CON groups, respectively. From the 454 pyrosequencing analysis, significant differences (P < 0.05) were observed in the relative abundance of several phyla (Bacteroidetes, Actinobacteria, and Tenericutes) and one genus (Prevotella) between the two groups. From quantitative real-time PCR analysis, the HAY group had the higher copy numbers of cellulolytic bacteria (Ruminococcus flavefaciens and Ruminococcus albus) compared with the CON group. This study demonstrated that feeding of dietary forage alleviates subacute ruminal acidosis due to diurnal changes in ruminal pH. Furthermore, changes in ruminal pH affect the ruminal bacterial diversity and relative abundance, and these changes might have influenced the establishment of fermentative ruminal functions during weaning transition.

Immune-stimulatory effects of a bacteria-based probiotic on peripheral leukocyte subpopulations and cytokine mRNA expression levels in scouring holstein calves.

ABSTRACT Subpopulations of peripheral leukocytes and cytokine mRNA expression levels were evaluated in scouring and healthy Holstein calves (age 10 ± 5 days; n=42) treated with a probiotic consisting of Lactobacillus plantarum, Enterococcus faecium and Clostridium butyricum. The calves were assigned to the scouring or healthy group and then subdivided into pathogen-positive treated (n=8), pathogen-positive control (n=8), pathogen-negative treated (n=6), pathogen-negative control (n=6), healthy treated (n=6) and healthy control (n=8) groups. A single dose of the probiotic (3.0 g/100 kg body weight) was given to each calf in the treatment groups for 5 days. Blood samples were collected on the first day of scour occurrence (day 0) and on day 7. In the scouring calves, smaller peripheral leukocyte subpopulations and cytokine mRNA expression levels were noted on day 0. The numbers of CD3+ T cells; CD4+, CD8+ and WC1+ γδ T cell subsets; and CD14+, CD21+ and CD282+ (TLR2) cells were significantly increased in the scouring and healthy treated calves on day 7. Furthermore, interleukin-6, tumor necrosis factor-alpha and interferon-gamma mRNA expression was elevated in the peripheral leukocytes of the scouring and healthy treated calves on day 7. The scouring calves given the probiotic recovered on day 7. A significantly smaller number of peripheral leukocytes and lower cytokine mRNA expression level might be induced by scouring in calves. Repeated probiotic administration might stimulate cellular immunity and encourage recovery from scouring in pre-weaning Holstein calves.

Effects of dietary forage and calf starter on ruminal pH and transcriptomic adaptation of the rumen epithelium in Holstein calves during the weaning transition.

We investigated the relationship between ruminal pH and transcriptomic adaptation of the rumen epithelium (RE) of calves fed calf starter with and without forage during the weaning transition. Holstein calves were assigned to groups fed calf starter either with forage (HAY group, n = 3) or without forage (CON group, n = 4). Ruminal pH was measured continuously, and rumen fluid and epithelium were collected 3 wk after weaning. mRNA expression profiles of the RE were examined by one-color microarray. Differentially expressed genes (DEGs) were investigated using the Ingenuity Pathway Analysis (IPA). Mean and maximum ruminal pH were significantly (P < 0.05) higher, and the duration of pH < 5.8 during 1 day was significantly (P < 0.05) shorter, in the HAY group. The proportion of ruminal acetate and the acetate-to-propionate ratio were significantly (P < 0.05) lower in the CON group. DEGs encoding transcription regulators (SREBP1), insulin-like growth factor binding proteins (IGFBP7 and CTGF), ketogenic enzymes (HMGCL, BDH1, and BDH2), and a transporter (SLC16A3) were identified (P < 0.05) between the two groups. A growth factor (TGFB1) and signaling pathway (EGF and EGFR) were activated as upstream regulators. These results suggest that dietary forage alleviates ruminal acidosis, and the decrease in ruminal pH may damage the RE, leading to changes in gene expression to repair the damage. Furthermore, rumen development may be regulated by growth factor (TGFB1) and signaling pathways (EGF and IGFBP) for adaptation to feeding on calf starter with and without forage during the weaning transition.

Estimation of Glomerular Filtration Rate in Cynomolgus Monkeys (Macaca fascicularis)

ABSTRACT To estimate the glomerular filtration rate (GFR) in cynomolgus monkeys (Macaca fascicularis), a three-blood-sample method using iodixanol was assessed in comparison with the conventional multisample strategy using inulin. Iodixanol and inulin were coadministered intravenously 40 mg I/kg and 50 mg/kg, respectively, to male monkeys, followed by blood collection 60, 90 and 120 min later. A close correlation (r=0.96) was noted between the GFR values estimated by both methods. In clinically healthy monkeys, the basal values were determined to be 3.06 ± 0.50 ml/min/kg. This is the first report, suggesting that serum clearance of iodixanol is a ready-to-use tool for a screening the GFR in monkeys, although it is necessary to perform a more longitudinal study using animals with reduced renal function.

Effects of a bacteria-based probiotic on subpopulations of peripheral leukocytes and their cytokine mRNA expression in calves.

ABSTRACT Eight Holstein calves (10 ± 3 weeks) were used to examine the interaction between a bacteria-based probiotic agent (probiotic) and the function of peripheral blood mononuclear cells (PBMCs). The probiotic, consisting of Lactobacillus plantarum, Enterococcus faecium and Clostridium butyricum, was administered orally at 3.0 g/100 kg body weight to calves once daily for 5 consecutive days. Calves given the vehicle alone with no probiotic served as the control. In the treatment group, increases in numbers of CD282+ (TLR2) monocytes, CD3+ T cells and CD4+, CD8+ and WC1+ γδ T cell subsets were noted on day 7 post-placement compared to predose day and the control group. Expression of interleukin (IL)-6, interferon-gamma (INF-γ) and tumor necrosis factor-alpha (TNF-α) was elevated in peripheral leukocytes on days 7 and 14. These results suggest that peripheral blood leukocytes in healthy calves may be stimulated via the gastrointestinal microbiota, which was increased by the oral probiotic treatment, with overall stability of the rumen bacterial flora. The 5-day repeated administration of a bacteria-based probiotic may enhance cellular immune function in weaned calves.

First detection of Allobilharzia visceralis (Schistosomatidae, Trematoda) from Cygnus cygnus in Japan

Adult schistosomes were detected in the veins or capillaries of the large intestine, mesentery, liver, and adrenal glands in eight of 13 whooper swans (Cygnus cygnus) examined in Iwate Prefecture, Japan. However, neither eggs nor severe tissue injuries were observed in any of the swans. The schistosomes were definitively identified as Allobilharzia visceralis based on the nucleotide sequences of the ribosomal internal transcribed spacer (ITS) region. Allobilharzia visceralis infections have been reported in whooper swan in Iceland and tundra swan (Cygnus columbianus) in North America. These detections suggest that A. visceralis is distributed extensively along the swan flyways because the swans are migratory birds. To the best of our knowledge, this is the first report of A. visceralis infection in Asia.

Vertical transmission of Mycoplasma wenyonii in cattle, supported by analysis of the ribonuclease P RNA gene - Short communication.

The vertical transmission of Mycoplasma (M.) wenyonii was investigated in beef cattle raised on a farm in Japan by analysing the ribonuclease P RNA (rnpB) gene sequence using PCR. Peripheral blood samples from 17 dams infected with M. wenyonii and from their neonatal calves were collected and colostrum samples were taken from cows immediately after parturition, and subsequently the blood samples of calves were monitored continuously for three months. At birth on day 0, although no rnpB gene was detected in the colostrum of any of the dams, four (23.5%) of the 17 calves born were positive. At three months after delivery, the number of positive calves decreased to three. Although horizontal transmission by blood-feeding arthropod vectors has been basically accepted as the most common route of haemoplasma infection, these findings suggest that vertical transmission is, at least in part, another most likely route of M. wenyonii infection in cattle.

Prognostic Judgment at Post-Surgery by Biochemical Parameters in Beef Cattle with Left Displaced Abomasum

ABSTRACT We examined whether the postoperative prognosis of beef cattle with left displaced abomasum (LDA) can be estimated from changes in laboratory parameters. Preoperatively, beef cattle with LDA showed increases in plasma glucose with decreased serum insulin in the glucose tolerance test compared to non-LDA cattle. Postoperatively, the cattle with LDA were retrospectively divided into two groups, good and bad prognoses. Although plasma glucose concentrations significantly increased either pre- or postoperatively, no difference was noted between the good and bad prognosis groups. Serum insulin concentrations in the bad prognosis group significantly decreased, compared to those in the good prognosis group. These findings suggest that beef cattle with LDA elicit disturbed glucose metabolite pre- and postoperatively, and serum insulin levels may predict their prognoses after surgery.

Haemotropic Mycoplasma Infection Revealed by Real-Time PCR in Specific Pathogen-Free Rats

Abstract The presence of Mycoplasma haemomuris (haemoplasma) in blood samples collected from specific pathogen-free (SPF) laboratory rats bred in Japan was reported. Its presence was examined in Fischer 344, Sprague-Dawley (SD), and Wistar rat strains of both sexes by real-time PCR. All strains were positive for M. haemomuris infection. The 16S rRNA gene of M. haemomuris strain detected in the animals was amplified using end-point PCR. Only the entire nucleotide sequence of 16S rRNA gene of a mycoplasma strain detected in SD rats was determined and compared to those of other haemoplasmas. Our investigations suggest a wide M. haemomuris infection among the SPF rats purchased from commercial breeders in Japan.