Kouya Sasaki

A novel technique of ultrasound-guided brachial plexus block in calves.

An interventional ultrasound technique to increase the safety of surgical treatment of the calf forelimb was tested. First, the brachial plexus was evaluated using ultrasonography and then 2% lidocaine was injected under ultrasound guidance. Ultrasonically, the brachial plexus appeared as multiple hypoechoic areas surrounded by a hyperechoic rim or a hyperechoic structure characterised by multiple discontinuous lines. It was located between the omotransverse muscle and axillary artery and vein. The sensitive effect in the forelimb was seen mainly in the area supplied by the musculocutaneous nerve, indicating successful blockage in the nerve plexus. Out of the eight forelimbs, the motor effect was observed in seven forelimbs. These results suggest the clinical feasibility of ultrasound-guided brachial plexus block in bovine medicine, although further studies are needed to examine various approaches, including the sites of needle insertion and the appropriate volume and dosage of anaesthetic.

Diurnal Variation of Plasma Bone Markers in Japanese Black Calves

ABSTRACT To evaluate diurnal variation of plasma bone markers, blood samples were collected from five calves at 2-hr intervals throughout a 24-hr period. Tartrate-resistant acid phosphatase isoform 5b (TRAP5b), carboxy-terminal collagen crosslinks of type-I collagen (CTX), hydroxyproline, bone specific alkaline phosphatase (BALP) and osteocalcin were measured. Cosinor analysis showed a significant rhythm in all bone markers. The acrophase of each bone marker appeared from the early to late morning. The percentage ratio of the amplitude to mesor and the within-subject variability for CTx and osteocalcin were significantly larger than those for TRAP5b and BALP. This marked diurnal variation in five bone markers suggested that the time of blood sampling should be fixed when studying bone marker concentrations in bovine plasma.

N, N-Dimethylglycine decreases oxidative stress and improves in vitro development of bovine embryos

The antioxidant effect of N, N-dimethylglycine (DMG) on in vitro-produced (IVP) bovine embryos was examined. After in vitro fertilization, presumptive zygotes were cultured with or without 0.1 μM DMG under different oxygen tensions. The percentage of embryos developing to the blastocyst stage was lowest under a 20% oxygen concentration without DMG, and it was significantly increased (P < 0.05) by applying a 5% oxygen concentration. Under the 20% oxygen concentration, supplementation of the medium with DMG significantly improved blastocyst development, which was nearly equal to that achieved under 5% oxygen without DMG. Furthermore, a tendentious increase (P = 0.06) in blastocyst cell numbers was observed when DMG was applied. In the second experiment, addition of H2O2 (0.5 mM) to the culture medium significantly (P < 0.01) reduced the percentage of embryos developing to the blastocyst stage. However, DMG supplementation prevented this reduction. In conclusion, DMG enhanced the in vitro development of IVP bovine embryos by acting as an antioxidant.

Plasma fluctuation in estradiol-17β and bone resorption markers around parturition in dairy cows.

Blood samples were obtained sequentially from 10 dairy cows around the time of parturition to assess plasma fluctuations in estradiol-17β (E2) levels in association with those of several bone resorption markers. Plasma E2 concentration increased sharply a few days prepartum and decreased quickly after parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and was maintained at this level to a few days postpartum. The plasma concentration of carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly after parturition. These observations suggest that osteoclast-mediated bone resorption was activated after parturition when plasma E2 concentrations decreased.

Microarray-based gene expression profiling of peripheral blood mononuclear cells in dairy cows with experimental hypocalcemia and milk fever

Although a molecular diagnostic assay using clinically accessible tissue, such as blood, would facilitate evaluation of disease conditions in humans and animals, little information exists on microarray-based gene expression profiling of circulating leukocytes from clinically hypocalcemic cows. Therefore, peripheral blood mononuclear cells from dairy cows with experimentally induced hypocalcemia or spontaneous milk fever were subjected to oligo-microarray analysis to identify specific biomarker genes. In experimental hypocalcemia induced by a 4-h infusion of 10% disodium EDTA (n=4), 32 genes were significantly up- or downregulated compared with control treatment (4-h infusion of 11% calcium EDTA; n=4). In cows with milk fever (n=8), 98 genes were expressed differentially (either up- or downregulated) compared with healthy parturient cows (n=5). From these data, the following 5 genes were selected as being strongly related to both experimental hypocalcemia and milk fever: protein kinase (cAMP-dependent, catalytic) inhibitor β (PKIB); DNA-damage-inducible transcript 4 (DDIT4); period homolog 1 (PER1); NUAK family, SNF1-like kinase, 1 (NUAK1); and expressed sequence tag (BI537947). Another gene (neuroendocrine secretory protein 55, NESP55) was also determined to be specific for milk fever, independently of hypocalcemia. The mRNA expression of these 6 genes in milk fever cases was verified by quantitative real-time reverse-transcription PCR and was significantly different compared with their expression in healthy parturient cows. In the present study, the selected genes appeared to be candidate biomarkers of milk fever because the continuous interactions between blood cells and the entire body suggest that subtle intracellular changes occur in association with disease. However, before any genomic biomarkers are incorporated into clinical evaluation of the disease, the effect of hypocalcemia on the mRNA expression of these genes in the tissues that regulate calcium homeostasis in dairy cows should be determined.

Relationship between sex hormone fluctuations and biomarkers of bone resorption in bovine plasma during the oestrous cycle.

The objective of this study was to determine the potential influence of fluctuations in the sex hormones progesterone and oestradiol-17β (E(2)), on biomarkers of bone resorption (hydroxyproline [HYP] and tartrate-resistant acid phosphatase isoform 5b [TRAP5b]) during the oestrous cycle of Holstein cows. Over the course of the study, plasma HYP concentrations did not change and alterations in the concentration of TRAP5b negatively correlated with E(2) levels: enhanced TRAP5b activity correlated with decreased E(2) concentrations below a defined level. This finding enhances the understanding of calcium homeostasis in post-partum dairy cows.

Correlation of blood metabolite concentrations and body condition scores with persistent postpartum uterine bacterial infection in dairy cows

To analyze the relationship of blood metabolite concentrations and body condition score (BCS) with persistent bacterial uterine infection, specifically that caused by Trueperella pyogenes and anaerobic bacteria, uterine bacteriological swabs (n = 128) were collected from 64 Holstein cows at 5 (W5) and 7 (W7) weeks postpartum, and the percentage of neutrophils in the endometrium was evaluated. Blood glucose, total cholesterol (T-cho), blood urea nitrogen (BUN), non-esterified fatty acid (NEFA), and β-hydroxybutyric acid concentrations were analyzed at 3 weeks (W-3) and 1 week (W-1) prepartum and W3, W5, and W7 postpartum. BCS were evaluated at W-3, W3, and W7. Blood glucose concentrations at W-3 and W-1 in cows with persistent bacterial infection were lower (P = 0.05) than in the rest of the cows. Total BUN concentrations in cows with persistent bacterial infection were lower (P < 0.01) than those in other cows, although the association between the pre or postpartum time and status of infection was not significant. Total NEFA concentrations in cows with persistent bacterial infection were similar to those in uninfected cows and cows positive for infection at W5 but not W7. Total BCS in cows with persistent bacterial infection were lower (P < 0.01) than those in cows positive for infection at both W5 but not W7 and W7 but not W5; however, the association between the pre or postpartum time and status of infection was not significant. Glucose concentrations at W-3 and W-1 negatively correlated with persistent bacterial infection at W5 and W7 (P < 0.01). BUN concentrations at W3 (P < 0.01), W5 (P < 0.05), and W7 (P < 0.05) and BCS at W3 (P < 0.01) negatively correlated with persistent postpartum bacterial infection. Decreased prepartum blood glucose concentrations might be an important risk factor for persistent postpartum bacterial uterine infection in dairy cows.

Colorimetric assay for the quantification of serum iodixanol concentration and its application on estimation of glomerular filtration rate in cattle

A colorimetric assay used to quantify the non-ionic contrast medium iodixanol in sera was validated and compared with high-performance liquid chromatography. The application of this assay to estimate glomerular filtration rates (GFR) in cattle was examined. Serum iodixanol was de-iodinated by alkaline hydrolysis and the amount of released iodine was subsequently determined using a ceric arsenite method. There was a close correlation between the two methods using identical specimens. In clinically healthy cattle with different body weights, the reference value (166.3-178.8 mL/min/m(2)) based on body surface area was fairly stable as compared with that (2.13-3.63 mL/min/kg) based on body weight. Based on GFR data in healthy and renal-impaired cattle, when the GFR decreased to more than 60% of the reference value, serum urea nitrogen and creatinine concentrations increased. The colorimetric assay is a simple method for the estimation of GFR in cattle and requires no expensive equipment.