Characterisation of a type 2 bovine viral diarrhoea virus isolated from cattle in the UK

Two genotypes of bovine viral diarrhoea virus (BVDV) are recognised. Type 2 was first recognised when virulent strains caused significant losses among cattle in North America. Subsequently, BVDV type 2 has been found in many other countries, but recent studies have shown that only type 1 BVDV is circulating in the UK herds (sheep and cattle) with type 1a predominating. During routine genotyping of UK BVDV isolates, a type 2 isolate was identified. Phylogenetic analysis of the 5'-untranslated region of the viral genome showed it to be a BVDV type 2a, most similar to a low virulent US strain of BVDV type 2. Antigenic typing with a panel of monoclonal antibodies verified this classification. This is the first confirmed isolation of BVDV type 2 found circulating in the UK.     

Surgical management of gallbladder mucoceles in dogs: 22 cases (1999-2003)

OBJECTIVES: To describe preoperative, surgical, and postoperative findings and determine prognostic indicators and treatment recommendations in dogs treated surgically for gallbladder mucocele. DESIGN: Retrospective study. ANIMALS: 22 client-owned dogs. PROCEDURES: Medical records of dogs with gallbladder mucoceles that were treated surgically were reviewed. History, clinical signs, results of selected clinicopathologic analyses and abdominal ultrasonography, surgical procedure performed, results of histologic examination of a liver biopsy specimen, and survival time were recorded. Follow-up information was obtained via telephone interview with owners and referring veterinarians. RESULTS: Dogs were 7 to 15 years of age and had non-specific clinical signs (vomiting, anorexia, and lethargy). Physical examination findings included icterus, signs of depression, and signs of discomfort on palpation of the abdomen. Sixteen dogs had a definitive diagnosis and 6 dogs were strongly suspected of having a gallbladder mucocele on the basis of results of abdominal ultrasonography. Fifteen dogs survived after surgery; 3 of these dogs had bile-induced peritonitis, and 4 had pancreatitis. One dog was euthanatized as a result of severe pancreatitis, and 1 was euthanatized because of acute renal failure; 5 dogs died as a result of pancreatitis, cholecystitis, or bile-induced peritonitis. Hepatic abnormalities were detected histologically in all dogs. CONCLUSIONS AND CLINICAL RELEVANCE: No predictors of survival were identified. No associations between outcome of surgical treatment (survival vs nonsurvival) and preoperative findings, biliary rupture, surgical procedure performed, results of histologic examination of the liver, or development of pancreatitis were found. Cholecystoduodenostomy and cholecystectomy appear to be acceptable treatments for gallbladder mucocele.     

Fuel-powered artificial muscles

Artificial muscles and electric motors found in autonomous robots and prosthetic limbs are typically battery-powered, which severely restricts the duration of their performance and can necessitate long inactivity during battery recharge. To help solve these problems, we demonstrated two types of artificial muscles that convert the chemical energy of high-energy-density fuels to mechanical energy. The first type stores electrical charge and uses changes in stored charge for mechanical actuation. In contrast with electrically powered electrochemical muscles, only half of the actuator cycle is electrochemical. The second type of fuel-powered muscle provides a demonstrated actuator stroke and power density comparable to those of natural skeletal muscle and generated stresses that are over a hundred times higher.     

Single-cell analysis divides bovine monocyte-derived dendritic cells into subsets expressing either high or low levels of inducible nitric oxide synthase

Dendritic cells (DC) are important cells at the interface between innate and adaptive immunity. DC have a key role in antigen processing and presentation to T cells. Effector functions of DC related to innate immunity have not been explored extensively. We show that bovine monocyte-derived DC (mDC) express inducible nitric oxide synthase (iNOS) mRNA and protein and produce NO upon triggering with interferon-gamma (IFN-gamma) and heat-killed Listeria monocytogenes (HKLM). An immunocytochemical analysis revealed that a sizeable subset (20-60%) copiously expresses iNOS (iNOShi) upon IFN-gamma/HKLM triggering, whereas the other subset expressed low levels of iNOS (iNOSlo). Monocyte-derived macrophages (mMphi) are more homogeneous with regard to iNOS expression. The number of cells within the iNOSlo mDC subset is considerably larger than the number of dead cells or cells unresponsive to IFN-gamma/HKLM. The large majority of cells translocated p65 to the nucleus upon triggering by IFN-gamma/HKLM. A contamination of mDC with iNOS-expressing mMphi was excluded as follows. (i) Cell surface marker analysis suggested that mDC were relatively homogeneous, and no evidence for a contaminating subset expressing macrophage markers (e.g. high levels of CD14) was obtained. (ii) iNOS expression was stronger in iNOShi mDC than in mMphi. The use of maturation-promoting stimuli revealed only subtle phenotypic differences between immature and mature DC in cattle. Nevertheless, these stimuli promoted development of considerably fewer iNOShi mDC upon triggering with IFN-gamma/HKLM. Immunocytochemical results showed that although a significant proportion of cells expressed iNOS only or TNF only upon triggering with IFN-gamma/HKLM, a significant number of cells expressed both iNOS and TNF, suggesting that TNF and iNOS producing (TIP) DC are present within bovine mDC populations obtained in vitro.     

The effect of tuberculin testing on the development of cell-mediated immune responses during Mycobacterium bovis infection

Protection against tuberculosis (TB) is associated with Th1-type cell-mediated immunity (CMI). Whilst the intradermal injection of partially purified derivatives of tuberculin (PPD) represents the classic test assessing the delayed type hypersensitivity (DTH) response used in both humans and cattle for diagnosing TB, it has been suggested that the test may modulate host CMI responses. To investigate the kinetics of the development of the DTH response and its subsequent effect on CMI responses, groups of 6-month old calves were inoculated intranasally with 8 x 10(4) cfu of Mycobacterium bovis, subjected to the comparative intradermal tuberculin test (TT) using bovine and avian PPD (PPD-B, PPD-A) at various time intervals post-infection, and immune responses compared. These included DTH, lymphocyte proliferation, IgG production, and synthesis of the cytokines: IFNgamma, IL-10, IL-4, IL-6, and IL-13. All animals were subjected to post-mortem examination. The kinetics of the development of the DTH response assessed in the TT was such that infected cattle could be identified as early as 3 weeks post-infection, which correlated with the detection of an antigen-specific IFNgamma response. Transient increases in plasma-derived IFNgamma as a result of TT during an established TB infection were more pronounced when blood was stimulated with PPD-A compared with PPD-B stimulation. This has the potential to mask diagnosis of infection as a result of the stronger avian-bias if the IFNgamma test is used the week following TT. Disease pathology was not affected by TT. A transient failure to a second TT was observed in 1 of 30 animals and the time (post-infection) at which the TT is administered may be of significance. In serum, IgG responses to PPD-B, which were undetectable prior to TT, were elevated after TT and were most pronounced in cattle that were TT at 6 weeks post-infection. Other cytokines were also affected by the TT; IL-4 mRNA levels increased and IL-6 mRNA levels decreased, whilst PPD-B specific IL-10 protein synthesis was enhanced. These observations may offer the potential for further diagnostic assays that could complement the TT and IFNgamma test.     

Mycobacterium bovis cultured from commercially pasteurized cows' milk: laboratory cross-contamination

The ability of Mycobacterium paratuberculosis to survive the commercial pasteurization process of raw milk remains controversial. In a study undertaken in Venezuela to culture M. paratuberculosis from commercially pasteurized cows' milk, 83-200 ml containers of milk were processed and cultured on Herrold's egg yolk slants. No M. paratuberculosis was cultured but a total of six colonies of Mycobacterium bovis were isolated from one container each from two different milk providers. Because laboratory cross-contamination was suspected, the laboratory records were reviewed and spoligotyping was carried out on the isolated individual colonies. On the day before these milk specimens were processed, the biological safety cabinet had been used for the isolation of M. bovis from lymph nodes from infected cattle. Spoligotyping showed that that the colonies isolated from the milk all had the same pattern as the strains isolated from the lymph nodes that were processed the previous day. As far as we know, this is the first report of cross-contamination in a veterinary mycobacterial laboratory. False-positive cultures in the mycobacterial laboratory are not rare. In this setting M. bovis was isolated because it is the most common manipulated organism in this laboratory. We believe that reports on the isolation of M. paratuberculosis from commercially pasteurized milk should exclude cross-contamination before reporting, especially when this organism is routinely isolated from animal material in the same lab.     

The provenances of asteroids, and their contributions to the volatile inventories of the terrestrial planets

Determining the source(s) of hydrogen, carbon, and nitrogen accreted by Earth is important for understanding the origins of water and life and for constraining dynamical processes that operated during planet formation. Chondritic meteorites are asteroidal fragments that retain records of the first few million years of solar system history. The deuterium/hydrogen (D/H) values of water in carbonaceous chondrites are distinct from those in comets and Saturn's moon Enceladus, implying that they formed in a different region of the solar system, contrary to predictions of recent dynamical models. The D/H values of water in carbonaceous chondrites also argue against an influx of water ice from the outer solar system, which has been invoked to explain the nonsolar oxygen isotopic composition of the inner solar system. The bulk hydrogen and nitrogen isotopic compositions of CI chondrites suggest that they were the principal source of Earth's volatiles.     

Sentinel: An Early Yellow-Fleshed Potato Cultivar Suitable for Fresh Market and Chip Processing

Sentinel (FV8957-10) is a new yellow-fleshed potato cultivar that produces a high yield of attractive round to oval tubers at early harvest. Sentinel is suitable for fresh market use and chip processing. It was selected at the Lethbridge Research Centre of Agriculture and Agri-Food Canada, AB from a cross made at the Potato Research Centre of Agriculture and Agri-Food Canada, NB between breeding clones F72218 and F47024. Sentinel has erect medium-height vines and produces uniform tubers of medium-size with a light buff skin, light yellow flesh and shallow eyes. In multi-date-harvest trials, Sentinel produced similar or higher marketable yield compared to Atlantic and NorValley in southern Alberta. When harvested at 80 days after planting, Sentinel produced similar or greater yield than Superior and Conestoga at test sites across western Canada. Specific gravity of Sentinel was less than Atlantic and Conestoga but higher than NorValley and Superior, whereas chip colour was similar to Atlantic and lighter than NorValley or Superior. Sentinel showed little tendency to slough or to darken after cooking. It showed clear foliar and tuber symptoms when infected with bacterial ring rot. Sentinel is moderately susceptible to verticillium wilt, early blight, fusarium wilt and common scab and susceptible to late blight.