Effects of dietary molybdenum on nematode and host during Haemonchus contortus infection in lambs.

The addition of molybdenum (0.05 mmol kg-1 dry-matter) to the diet of lambs given a trickle infection of Haemonchus contortus larvae (500 third stage larvae d-1 over six weeks) reduced mean faecal egg counts (epg) from 3952 to 2312 +/- 402 by 32 days (P less than 0.02) and greatly reduced the mean number of worms recovered from the abomasum 14 days after infection ceased (907 compared with 4167: P less than 0.01). Infection reduced haemoglobin concentrations less in lambs given molybdenum although the difference was small relative to the reduction in worm burden. Lambs not given molybdenum had low intraepithelial mast cell counts in the abomasal mucosa and less abomasal hypertrophy than expected from abomasal parasitism. Molybdenum did not consistently reduce the copper status of the host or the parasite. Previous exposure to molybdenum greatly reduced protein but not proteinase activity in, or secreted by, adult worms cultured for eight hours. It is suggested that molybdenum either increased the inflammatory response which preceded worm rejection or that it indirectly enhanced that reaction by reducing the effectiveness of copper-dependent, anti-inflammatory enzymes in the gastrointestinal mucosa.     

An automated micro-method for the enzymatic determination of D-B-hydroxybutyrate in ruminant plasma

1. An enzymatic ‘reaction rate’ micro-method for the rapid routine estimation of D-B-hydroxybutyrate (D-B-HOB) in ruminant plasma, using an I.L. Multistat III centrifugal analyzer, is described.
2. Reaction conditions were optimized to give a linear response for plasma D-B-HOB concentrations between 100 and 2500 μmoles per litre, at 30°C and pH 9.0.
3. For the standardized method the within-run and between-run coefficients of variation for deproteinised ovine plasma were consistently less than 3.5%.
4. There was good agreement between plasma concentrations obtained by the present method and both original U.V. end-point technique (r=0.927b=0.950) and a colorimetric end-point procedure (r=0.937. b=0.879).
5. Utreated ovine and bovine plasma consistently exhibited high ‘blank’ activity and this was directly correlated with plasma lactate dehydrogenase (LDH) activity in both species (r=0.971; p<0.001 and r=0.949; p<0.001 respectively). The distribution of LDH activity in man was similar to sheep but, contrastingly, non-specific interference was extremely low in human plasma and unrelated to LDH. Horse, chicken and rat had negligible ‘blank” activity and comparatively low LDH levels. In both cattle and sheep non-specific interference was abolished by perchloric acid precipitation. In the sheep subtraction of ‘blank’ activity gave D-H-HOB concentrations for untreated plasma comparable to those in deproteinised samples. However, in the bovine, D-B-HOB levels remained significantly (t=6.44; p<0.001) higher even after ‘blank’ correlation. In contrast to man and other non-ruminants, perchloric acid precipitation is essential in ruminants to avoid false overestimation of plasma D-B-HOB levels.
6. Plasma with EDTA as anticoagulant and serum gave concentrations of D-B-HOB approximately 60% lower, than samples containing heparin or oxalate/fluoride. However, heparin was associated with much higher (up to 50%) non-specific NAD rduction than oxalate/fluoride.
7. High levels of acetoacetate (400–1000 μmoles per litre) reduced the recovery of D-B-HOB from ovine plasma by less than 10%. This effect was negated by the inclusion of hydrazine hydrates in the reaction mixture. Perchlorate ion concentrations above 25 μmoles per litre per test dramatically inhibited the assay in ovine plasma, and therefore precipitation conditions must be carefully controlled.
8. Plasma with oxalate/fluoride as anticoagulant showed the greatest stability in storage; 24 hours at room temperature, one week at +4°C and at least one month at ?20°C.

     

Cases of Pseudorabies in Free-Living Red Foxes (Vulpes Vulpes) and in Captive Blue Foxes (Alopex Lagopus) in Denmark

In the period December 1967 through April 1969 eight spontaneous cases of pseudorabies in Danish red foxes were demonstrated by virus isolation. One fox had been kept in captivity, the remaining seven were free-living. Five of the foxes were found dead, while three, presenting abnormal behaviour when encountered, had been killed.     

Peripartal Endocrinology in the Mare and Foetus

The endocrine profiles in the periparturient mares are dominated by increasing concentrations of progestagens and decreasing oestrogens. These hormones are produced by precursors from the foetus, metabolized by the placenta and act primarily on the maternal uterus. The circulating concentrations of hormones in maternal plasma, generally, represent a small proportion of those metabolized by the foetus and utero-placental tissues. There is clear evidence that the foetal hypothalamo-pituitary-adrenal (HPA) axis initiates the process of foetal maturation and the hormonal cascade which culminates in parturition at term. The endocrine changes associated with abnormal pregnancy and abortion in late pregnancy are less well understood, as are the hormonal treatments needed to avert these problems. Further work is needed to establish the biological role of the various hormones present in pregnant mares and, in particular, those hormones which control myometrial quiescence.     

Detection of Ureaplasma diversum in the upper airways of Australian feedlot cattle

Bovine respiratory disease (BRD) exerts a major impact on the beef cattle industry nationally and worldwide, with a range of aetiological factors impacting its pathogenesis. Previous research has focussed on an increasing number of bacteria and viruses that have been shown to play a role in eliciting disease. Recently, additional agents have been emerging as potential contributors to BRD, including the opportunistic pathogen Ureaplasma diversum. To determine if U. diversum was present in Australian feedlot cattle and if that presence was linked to BRD, nasal swabs were collected from a cohort of 34 hospital pen animals and compared to 216 apparently healthy animals sampled contemporaneously at feedlot induction and again after 14 days on feed at an Australian feedlot. All samples were subjected to a de novo polymerase chain reaction (PCR) assay targeting U. diversum in combination with other BRD agents. U. diversum was detected at a low prevalence in cattle at induction (Day 0: 6.9%, Day 14: 9.7%), but in a significantly greater proportion of cattle sampled from the hospital pen (58.8%). When considering the presence of other BRD-associated agents, co-detection of U. diversum and Mycoplasma bovis was most common in hospital pen animals receiving treatment for BRD. These findings suggest that U. diversum may be an opportunistic pathogen involved in the aetiology of BRD in Australian feedlot cattle, in combination with other agents, with further studies are warranted to identify if a causal relationship exists.     

Profile of Steroid Receptors and Increased Aromatase Immunoexpression in Canine Inflammatory Mammary Cancer as a Potential Therapeutic Target

Canine inflammatory mammary cancer (IMC) has been proposed as a model for the study of human inflammatory breast cancer (IBC). The aims of this study were to compare the immunohistochemical expression of aromatase (Arom) and several hormone receptors [estrogen receptor α (ERα), estrogen receptor β (ERβ), progesterone receptor (PR) and androgen receptor (AR)], in 21 IMC cases vs 19 non‐IMC; and to study the possible effect of letrozole on canine IMC and human inflammatory breast cancer (IBC) in vitro using IPC‐366 and SUM‐149 cell lines. Significant elevations of the means of Arom Total Score (TS), ERβ TS and PR TS were found in the IMC group (p = 0.025, p = 0.038 and p = 0.037, respectively). Secondary IMC tumours expressed higher levels of Arom than primary IMC (p = 0.029). Non‐IMC PR‐ tumours contained higher levels of Arom than non‐IMC PR+ tumours (p = 0.007). After the addition of letrozole, the number of IMC and IBC cells dropped drastically. The overexpression of Arom found and the results obtained in vitro further support canine IMC as a model for the study of IBC and future approaches to the treatment of dogs with mammary cancer, and especially IMC, using Arom inhibitors.     

Comparative Genomics for Gene Isolation in Legumes

The similarity in gene order between closely related taxa suggests that genomic information from model systems should facilitate gene isolation and characterization in target crops. If this is the case, a great deal of effort and investment can be saved by focusing attention on a few model systems that have appropriate applicability. Pea （Pisura sativum） provides a good test case： its genome is large and the insertion sites for repetitive elements, which comprise the bulk of its genome, are highly polymorphic （Jing et al., 2005; Vershinin et al., 2003）, so we expect a great deal of structural polymorphism between the genomes of Pisum lines. Yet the genetic map of Pisum is essentially coUinear with Medicago （Choi et al., 2004; Kalo et al., 2004）.