Studies on feline IgE

Feline reaginic antibody has been shown to be present in the serum of some cats with allergic skin disease or parasitic infections. However few studies have attempted to characterise feline IgE and the production of antisera specific for feline IgE has yet to be reported. The involvement of this isotype in feline allergic diseases is thus unclearThe first aim of these studies was to purify and characterise feline IgE to produce specific polyclonal antisera and investigate anitigen-specific IgE responses in cats. Cats naturally or experimentally infected with T. cati were immunised with dinitrophenylated ascaris antigen (DNP-Asc). All cats developed immediate skin reactivity to DNP coupled to bovine serum albumin (DNP-BSA) and the sera of the nine cats had a heat labile homocytotropic antibody detectable by Prausnitz-Kiistner (PK) tests. Reagin-rich fractions were prepared from these sera by a variety of techniques and used for the preparation of antisera in rabbits. Resultant antisera were passed through an immunoabsorbent column of heated normal cat serum. An immunoabsorbent column prepared with the putative anti-IgE serum removed PK reactivity from the cat sera, and the reactivity was recovered following acid elution. The antiserum failed to detect any recognised immunoglobulin in cat sera but precipitated with a heat labile protein with y-1 electrophoretic mobility in the sera of parasitised cats. These findings support the contention that the antiserum is specific for feline IgE.Ten normal cats were immunised with Dermatophagoides farinae (DF) antigen and intradermal skin tests (IDSTs) were performed weekly. Sera from the latter were also assessed for DF-specific IgE by ELISA and PK tests. Detectable DF-specific IgE was induced in all of the 10 cats, however levels were found not to be correlated with the development of positive IDSTs nor with the levels of IgE as assessed by PK tests.Sera from 10 cats with symptoms consistent with atopy, from 15 normal household cats and from 11 laboratory maintained cats were assessed for allergen-specific IgE and IgG to DF by ELISA. Although DFspecific IgE was detectable in all the atopic cats, there was no significant difference between the levels in this group and in the clinically normal household cats. However levels in both these groups were significantly higher than those in the laboratory maintained cats.The influence of vaccination and endoparasitism on the IgE response to a food antigen was assessed in 34 cats. Seventeen kittens experimentally infected with T. cati and 17 parasite-free kittens were dosed with human serum albumin (HSA) daily for 3 weeks. Seven cats from both groups were given two injections of a live attenuated viral vaccine. The group of parasitised cats had significantly higher levels of HSAspecific IgE, IgG and IgA than did the group of parasite-free cats. Vaccinated cats had also higher levels than non vaccinated cats but only in the group of parasite-free cats. None of the cats developed clinical signs of food allergy.The findings from these studies are strongly suggestive of the existence of a heterogeneity of IgE in cats, and imply that endoparasitism and vaccination have an immunomodulatory role on the antigen specific antibody response

Environmental drivers of deer population dynamics and spatial selection in Southeast Alaska

Thesis (Ph.D.) University of Alaska Fairbanks, 2015The coastal temperate rainforest is one of the rarest ecosystems in the world, and a major portion of the global total is found in Southeast Alaska. In this ecosystem, Sitka black-tailed deer are the dominant large herbivore, influencing large carnivores that prey on deer such as wolves and bears, as well as plant species and communities through browsing. In addition, deer play an important economic and cultural role for humans in Southeast Alaska, making up the large majority of terrestrial subsistence protein harvested each year as well as providing the backbone of a thriving tourism industry built around sport hunting. Given the importance of deer in this system, there remain a surprisingly large number of key gaps in our knowledge of deer ecology in Southeast Alaska. These knowledge gaps are potentially troubling in light of ongoing industrial timber-harvest across the region, which greatly alters habitat characteristics and value to wildlife. This dissertation research project was undertaken with the aim of filling several connected needs for further understanding deer ecology, specifically 1) patterns of reproduction and fawn survival, 2) population dynamics in response to environmental variability, and the underlying drivers of spatial selection during 3) reproduction and 4) winter. To fill these knowledge gaps, I developed robust statistical tools for estimating rates of fawn survival, and found that fawns must be captured at birth, rather than within several days of birth, in order to produce unbiased estimates because highly vulnerable individuals died quickly and were thus absent from the latter sample. I then use this robust approach to estimate vital rates, including fawn survival in winter and summer, and developed a model of population dynamics for deer. I found that winter weather had the strongest influence on population dynamics, via reduced over-winter fawn survival, with mass at birth and gender ratio of fawns important secondary drivers. To better understand deer-habitat relationships, I examined both summer and winter habitat selection patterns by female deer. Using summer-only data, I asked how reproductive female deer balance wolf and bear predation risk against access to forage over time. Predation risks and forage were strong drivers of deer spatial selection during summer, but reproductive period and time within reproductive period determined deer reaction to these drivers. To ensure adequate reproductive habitat for deer, areas with low predation risk and high forage should be conserved. Focusing on winter, I evaluated deer spatial selection during winter as a response to snow depth, vegetation classes, forage, and landscape features. I allowed daily snow depth measures to interact with selection of other covariates, and found strong support for deer avoidance of deep snow, as well as changes in deer selection of old-growth and second-growth habitats and landscape features with increasing snow depth. Collectively, this dissertation greatly improves our understanding of deer ecology in Alaska, and suggests habitat management actions that will help ensure resilient deer populations in the future

Déjouer l’impasse du lien et de la parole : D’autres repères pour l’aide en itinérance

L’intervention auprès des jeunes adultes itinérants est empreinte de difficultés et de paradoxes qui se dévoilent tant dans l’établissement d’une relation d’aide que dans celui d’une communication à la fois désirée et évitée. L’analyse qualitative en profondeur d’entretiens de recherche menés auprès de ces jeunes et des aidants qui les côtoient a permis de cerner trois points d’ancrage de l’aide proposée à ces jeunes, qui permettent de contourner les obstacles associés au lien et à la parole. La discussion ainsi amorcée autour des concepts de position des acteurs, de cadre d’intervention et de mouvement de la relation d’aide suggère un nouveau regard sur les processus qui dynamisent l’intervention menée auprès de ces jeunes adultes.Intervention in the field of homelessness is fraught with challenges that stem noticeably from the paradoxical nature of the wish for and simultaneous avoidance of ties and communication. Through a qualitative research design using in-depth interviews with both parties, three anchoring dimensions of intervention among young homeless adults are explored in terms of their potential for avoiding such pitfalls

Spatial mode estimation for functional random fields with application to bioturbation problem

This work provides a useful tool to study the effects of bioturbation on the distribution of oxygen within sediments. We propose here heterogeneity measurements based on functional spatial mode. To obtain the mode, one usually needs to estimate the spatial probability density. The approach considered here consists in looking each observation as a curve that represents the history of the oxygen concentration at a fixed pixel

Internal friction investigation of phase transformation in nearly stoichiometric LaMnO3+δ

Rhombohedral LaMnO3+δ powders, prepared by two different soft chemistry routes (co-precipitation and hydrothermal synthesis), are sintered at 1400 °C for 2 h in air. Measurements of internal friction Q−1(T) and shear modulus G(T), at low frequencies from −180 to 700 °C under vacuum, evidence three structural transitions of nearly stoichiometric orthorhombic LaMnO3+δ. The first one, at 250 or 290 °C, depending on the processing followed, is associated to either a Jahn–Teller structural transition or a phase transformation from orthorhombic to pseudo-cubic. The second one at 610 or 630 °C is related to a phase transformation from pseudo-cubic or orthorhombic to rhombohedral. Below the Neel temperature, around −170 °C, a relaxation peak could be associated, for samples prepared according to both processing routes, to the motion of Weiss domains

Public wealth, public health, and private stealth: Australia's black market in cigarettes

Taxes on tobacco provide a significant income for the Australian government – $5.1 billion in 2001. At the same time, health officials are making strenuous efforts to reduce smoking, particularly among teenagers. Some economists suggest that raising taxes on tobacco will produce more revenue while at the same time lowering smoking rates, particularly among youths who have less discretionary spending power than adults. But a by-product of excise tax in Australia has been the emerging market in ‘chop-chop,’ tobacco diverted from legal channels by growers who receive considerably higher prices for a part of their yield than they can obtain from legal manufacturers. The article details this situation and suggests that only bold solutions may be able to reduce tensions in tax policies, smoking rates and the ‘chop-chop’ black market