Requirement for MHC class II positive accessory cells in an antigen specific bovine T cell response

Purified populations of bovine antigen presenting cells (APCs) and T cells have been isolated from peripheral blood and characterised using various monoclonal antibodies (mAbs) for cell surface markers. Bovine APCs were found in an adherent cell fraction and were non-specific esterase positive, phagocytic and expressed bovine major histocompatibility complex (MHC) class II determinants, all of which are typical macrophage characteristics. T cells were rigorously depleted of accessory cell function before being used in an antigen presenting cell assay. The generation of T helper cells in response to the soluble antigen, ovalbumin, was entirely dependent upon a critical number of APCs. Further the proliferative response was inhibited by several mAbs to bovine MHC class II molecules. Thus the interaction between bovine APCs and helper/inducer T lymphocytes (TH/I) appears to be similar to that in other species.     

Percutaneous absorption of chemicals: developing an understanding for the treatment of disease in frogs

The permeable nature of frog skin presents an alternative route for the delivery of therapeutic chemicals to treat disease in frogs. However, although therapeutic chemicals are often topically applied to the skin of frogs, their pharmacokinetics have rarely been reported. To provide evidence to guide both candidate drug and formulation selection, we highlight factors expected to influence percutaneous absorption through frog skin, including the anatomy and physiology of the skin and the physicochemical properties of applied therapeutic chemicals. Importantly, we also highlight the effects of the formulation on percutaneous absorption, especially the inclusion of potential penetration enhancers as excipients. Finally, we collate empirical data on the topical application of various therapeutic chemicals in postmetamorphic frogs and show that, in contrast to mammalian species, even large chemicals (i.e. >500 Da) and those with a wide range of log P values (?4 through +6) are likely to be absorbed percutaneously. Topical application in frogs thus promises a convenient and effective method for delivering systemic treatments of a diverse range of chemicals; however, further experimental quantification is required to ensure optimal outcomes.     

Characterization of house dust mite and scabies mite allergens by use of canine serum antibodies

OBJECTIVE: To identify the major allergenic proteins from the 3 main species of dust mites to which dogs react (Dermatophagoides farinae, D. pteronyssinus, and Euroglyphus maynei) and evaluate the potential cross-reactivity of dust mite allergens with antigens from the ectoparasitic mite Sarcoptes scabiei var canis. SAMPLE POPULATION: Sera from 83 dogs with atopic dermatitis. PROCEDURE: Sodium dodecylsulfate-polyacrylamide gel electrophoresis and immunoblotting using serum from atopic dogs was used to identify IgE-binding proteins in extracts of the 4 mite species. RESULTS: Sera of atopic dogs contained IgE against 23, 17, 25, and 17 allergens from D. farinae, D. pteronyssinus, E. maynei, and S. scabiei, respectively. Unlike the situation for humans, the major allergens for dogs are mostly proteins that are larger than 90 kd molecular weight. Dermatophagoides farinae and E. maynei appear to be more allergenic for dogs than is D. pteronyssinus. Some dogs with serum IgE against dust mites also had IgE against antigens of S. scabiei var canis. CONCLUSIONS AND CLINICAL RELEVANCE: Multiple dust mite allergens induce an IgE response in dogs. These allergens are mostly greater than 90 kd molecular weight.     

A modified bilateral transfrontal sinus approach to the canine frontal lobe and olfactory bulb: surgical technique and five cases

Five adult dogs presented for an acute onset of seizure activity. Magnetic resonance imaging revealed lesions in the olfactory bulbs, frontal lobes of the cerebrum, or both. A modified bilateral transfrontal sinus craniotomy was performed on each patient. The goal of removing the lesion was to relieve clinical signs and to provide tissue for histopathological diagnosis. In each instance, excision of the lesion was possible using this approach. No postoperative complications were observed. The modified bilateral transfrontal sinus craniotomy provides excellent access to the canine olfactory bulbs and frontal lobes.     

Cryopreservation of Piau‐Breed Wild Boar Sperm: Assessment of Cooling Curves and Centrifugation Regimes

This study aimed to assess the effects of different cooling curves and centrifugation regimes used in cryopreservation protocols on the post‐thaw viability of Piau‐breed wild boar (Sus scrofa) sperm using in vitro assessment tests. Two centrifugations (800  g for 10 min and 2400  g for 3 min) and two cooling curves (conventional cooling using nitrogen vapour – freezing 1 and automated cooling using a programmed freezing machine – freezing 2) were tested. Therefore, the treatments were divided into M3 – centrifugation at 2400  g for 3 min and freezing 2; M10 – centrifugation at 800  g for 10 min and freezing 2; R3 – centrifugation at 2400  g for 3 min and freezing 1; and R10 – centrifugation at 800  g for 10 min and freezing 1. No significant differences (p > 0.05) between treatments occurred post‐thawing regarding the total sperm motility means recorded. The mean values of the different treatments were not different from each other regarding the supravital staining (SV), hypo‐osmotic test (HO), sperm–egg binding assay or sperm morphology. This study showed that both the cooling curve and the centrifugation regime affected the quality of post‐thaw sperm, and centrifugation for shorter times and cooling curves using automated cooling are the most suitable for minimizing sperm injury.     

Light level thresholds for visual reaction of mackerel, Scomber scombrus L., to coloured monofilament nylon gillnet materials

A continuously swimming school of 12 dark-adapted mackerel was challenged to show visual reaction to barriers made from horizontal parallel lines (5 cm apart) of either monofilament nylon (0.40 mm diameter) gillnet material or, for comparison, the more visible twisted multifilament nylon (1.73 mm diameter). Six colours of each material were tested. The barriers were placed across the path of the approaching mackerel school while their behaviour was observed at low intensities of green light arranged to mimic undersea conditions. At very low light levels, the mackerel swam without hesitation through the barrier, whereas at higher light levels they turned or paused, indicating that they visually aware of the presence of the lines. The light level thresholds for visual reaction for the six colours of monofilament nylon were between −0.06 and −1.0 log lx, and for the same colours of twisted multifilament nylon were between −1.8 and −3.6 log lx. These findings are discussed in relation to the natural intensities of light in the sea, and the prediction of the visibility of drift and gillnet materials.