Postmortem observations on rumen wall histology and gene expression and ruminal and caecal content of beef cattle fattened on barley-based rations.

Sub-acute ruminal acidosis (SARA) can reduce the production efficiency and impair the welfare of cattle, potentially in all production systems. The aim of this study was to characterise measurable postmortem observations from divergently managed intensive beef finishing farms with high rates of concentrate feeding. At the time of slaughter, we obtained samples from 19 to 20 animals on each of 6 beef finishing units (119 animals in total) with diverse feeding practices, which had been subjectively classified as being high risk (three farms) or low risk (three farms) for SARA on the basis of the proportions of barley, silage and straw in the ration. We measured the concentrations of histamine, lipopolysaccharide (LPS), lactate and other short-chain fatty acids (SCFAs) in ruminal fluid, LPS and SCFA in caecal fluid. We also took samples of the ventral blind sac of the rumen for histopathology, immunohistopathology and gene expression. Subjective assessments were made of the presence of lesions on the ruminal wall, the colour of the lining of the ruminal wall and the shape of the ruminal papillae. Almost all variables differed significantly and substantially among farms. Very few pathological changes were detected in any of the rumens examined. The animals on the high-risk diets had lower concentrations of SCFA and higher concentrations of lactate and LPS in the ruminal fluid. Higher LPS concentrations were found in the caecum than the rumen but were not related to the risk status of the farm. The diameters of the stratum granulosum, stratum corneum and of the vasculature of the papillae, and the expression of the gene TLR4 in the ruminal epithelium were all increased on the high-risk farms. The expression of IFN-γ and IL-1ß and the counts of cluster of differentiation 3 positive and major histocompatibility complex class two positive cells were lower on the high-risk farms. High among-farm variation and the unbalanced design inherent in this type of study in the field prevented confident assignment of variation in the dependent variables to individual dietary components; however, the CP percentage of the total mixed ration DM was the factor that was most consistently associated with the variables of interest. Despite the strong effect of farm on the measured variables, there was wide inter-animal variation.

Speckle variance OCT for depth resolved assessment of the viability of bovine embryos.

The morphology of embryos produced by in vitro fertilization (IVF) is commonly used to estimate their viability. However, imaging by standard microscopy is subjective and unable to assess the embryo on a cellular scale after compaction. Optical coherence tomography is an imaging technique that can produce a depth-resolved profile of a sample and can be coupled with speckle variance (SV) to detect motion on a micron scale. In this study, day 7 post-IVF bovine embryos were observed either short-term (10 minutes) or long-term (over 18 hours) and analyzed by swept source OCT and SV to resolve their depth profile and characterize micron-scale movements potentially associated with viability. The percentage of en face images showing movement at any given time was calculated as a method to detect the vital status of the embryo. This method could be used to measure the levels of damage sustained by an embryo, for example after cryopreservation, in a rapid and non-invasive way.

Serum trace metal and ceruloplasmin variability in individuals treated for pulmonary tuberculosis.

SETTING: Investigation of trace metal behaviour during the treatment of active pulmonary tuberculosis (PTB) patients residing in Romania. OBJECTIVE: To assess, follow and identify serum iron (Fe), copper (Cu) and zinc (Zn) levels in patients diagnosed and treated for active PTB. DESIGN: Chemical and statistical analysis of various biochemical parameters in 47 subjects diagnosed with active PTB and 170 healthy Romanian residents. RESULTS: Copper and ceruloplasmin levels were increased in patients with active PTB compared to the control group (P < 0.01), while the serum Zn level was significantly lower than in healthy subjects (P < 0.01) or within the normal range. The present study shows that there is a significant correlation between serum Cu concentrations and ceruloplasmin. CONCLUSIONS: This study provides preliminary evidence that Zn and Fe redistribution is operating as a primary host defence mechanism to reduce the availability of metals for microbial metabolism during infection. The study also calls attention to the fact that anti-tuberculosis treatment is sufficient to enhance the concentration of the antioxidant species (Cu and ceruloplasmin). The data obtained suggest that serum Cu, Zn and Cu/Zn levels may serve as indirect pointers in the diagnosis of a disease but they cannot be considered as specific markers for TB.

Acousto-optic compensation of tremor for use in a handheld laser microsurgical instrument.

Development of a handheld microsurgical manipulator that incorporates active cancellation of the hand tremor of the user is ongoing. Thus far, experiments with the instrument have involved mechanical tools or end-effectors. In considering the possibility of laser procedures with the instrument, it is conceivable that a laser version of the instrument could be developed with no moving parts, using acousto-optic deflection of the laser beam to compensate the tremor. The paper describes the application and presents a proof of concept in a single degree of freedom using a benchtop laser deflection system and recorded hand motion data. Operating with a hand motion input tremor amplitude of 4 microns rms, the average overall canceling error is 0.8 microns rms.