Antibody and Keratinocyte responses to Malassezia pachydermatis in dogs

Malassezia pachydermatis, a lipophilic, unipolar-budding yeast is a commensal on canine skin and it can be isolated from the skin and ear canals of healthy dogs. A dermatitis associated with elevated cutaneous populations of M. pachydermatis has been increasingly recognised in the last two decades and one of the most common underlying causes of Malassezia overgrowth in dogs is atopic dermatitis. The aim of these studies was to investigate two aspects of the host's protective responses against the organism - activation of a humoral immune response and thickening of the skin by epidermal hyperplasia.The interaction between M. pachydermatis and the host's immune system has not been widely studied either in normal or atopic dogs. To investigate antibody responses to M. pachydermatis, Western blotting techniques were used to detect Malassezia-specific IgG and IgE binding proteins from M. pachydermatis in atopic dogs with or without Malassezia dermatitis and normal dogs. By comparing the binding activity on the immunoblots, atopic dogs with Malassezia dermatitis showed much greater IgG and IgE responses to M. pachydermatis than normal dogs. The IgG in sera from the majority of the atopic dogs with Malassezia dermatitis recognised a 25 kDa protein, which was only seen in less than 25 % of the atopic dogs without Malassezia dermatitis and none of the normal dogs. Proteins of 45, 52, 56, and 63 kDa were recognised by IgE in more than 50 % of the atopic dogs with Malassezia dermatitis, but only recognised by a minority of normal dog sera, and therefore represented major allergens. These results suggest that Malassezia dermatitis in atopic dogs is associated with an IgG and IgE response to the organism, with the above proteins being most relevant in the immunological reaction.In addition to mounting immunological responses, the skin also undergoes biological changes in response to environmental insults. Epidermal hyperplasia is one of the major characteristics of skin biopsies from dogs with Malassezia dermatitis. The mechanisms by which M. pachydermatis induces epidermal lesions are not fully understood. To investigate the role of M. pachydermatis in the pathogenesis of epidermal hyperplasia associated with Malassezia dermatitis, a colourimetric cell proliferation assay was developed to evaluate the effect of extracts and culture supernatants from M. pachydermatis on proliferation of canine keratinocytes in vitro. Malassezia extracts, either with or without protease inhibitors, and culture supernatants from the yeast, did not affect the proliferation of normal canine keratinocytes in vitro. To further investigate the response of a direct interaction between canine keratinocytes and live Malassezia organisms, an in vitro co-culture system was developed. The proliferative response of the keratinocytes was assessed using direct manual counting and immunohistochemistry techniques. Malassezia organisms did not cause keratinocyte proliferation, but they induced keratinocyte detachment from the substratum and cell death. These results suggest that the epidermal hyperplasia seen in dogs with Malassezia dermatitis is unlikely to be caused by a direct effect of the organism on the keratinocyte cell cycle, but is likely to involve other mechanisms.These studies provide further information regarding the host response to M. pachydermatis, and suggest possible mechanisms by which overgrowth of Malassezia organisms causes pathological changes in the skin of dogs

Histological responses of azalea to Off-shoot-O and Dikegulac as chemical pinching agents

Histological responses to chemical pinching agents, Off-Shoot-0 and Dikegulac, applied as foliar sprays, were observed in shoot apices of Rhododendron obtusum \u27Hinodegiri.\u27 Tissues for paraffin and plastic embedding were fixed in buffered glutaraldehyde, and for plastic were further fixed in osmium tetroxide. The non-treated control shoot tips were characterized by large populations of cytoplasmic globules in a great range of sizes, some larger than nuclei. These globules were especially prominent in the trichomes of the differentiating primordial leaves, but were also present in the differentiating young stem tissue. The observation of these unique cellular inclusions was apparently the result of non-coagulant fixation, since they have not been reported from other studies in which coagulant fixation was employed. The large number of globules suggests that they may have an im-portant role in actively growing tissues. The composition of the glob-ules has not been identified. In this experiment, however, their color reaction with methylene blue-azure A in plastic sections suggests a phenolic composition, possibly a precursor to lignin In the globules. In the treatment with Off-Shoot-0, the globules in the trichomes disappeared three minutes after spraying. Dikegulac did not destroy the globules or other cellular inclusions, but the cells in the young primordial leaves and apical meristems of the shoot tips taken two weeks after treatment showed some changes compared with the non-treated shoot tips. Changes were observed in the color of the stained cel ls and there was increased vacuolization. Therefore, Dikegulac could interfere with the activities of plant hormones, especial ly auxin and cytokinin, in relation to apical dominance and side branching

TRANSFORMATIVE PLANNING: REFRAMING AND REFORMING THE YOUTH JUSTICE SYSTEM THROUGH THE JUVENILE DETENTION ALTERNATIVES INITIATIVE

Ph.D

Charged multiplicity density and number of participant nucleons in relativistic nuclear collisions

The energy and centrality dependences of charged particle pseudorapidity density in relativistic nuclear collisions were studied using a hadron and string cascade model, JPCIAE. Both the relativistic $p+\bar p$ experimental data and the PHOBOS and PHENIX $Au+Au$ data at RHIC energy could be fairly reproduced within the framework of JPCIAE model and without retuning the model parameters. The predictions for $Pb+Pb$ collisions at the LHC energy were also given. We computed the participant nucleon distributions using different methods. It was found that the number of participant nucleons is not a well defined variable both experimentally and theoretically. Thus it may be inappropriate to use the charged particle pseudorapidity density per participant pair as a function of the number of participant nucleons for distinguishing various theoretical models. A discussion for the effect of different definitions in nuclear radius (diffused or sharp) was given.Comment: 15 pages, 7 figure

On transverse momentum event–by–event fluctuations in string hadronic models

Transverse momentum event-by-event fluctuations are studied within the string-hadronic model of high energy nuclear collisions, LUCIAE. Data on non-statistical pT fluctuations in p+p interactions are reproduced. Fluctuations of similar magnitude are predicted for nucleus-nucleus collisions, in contradiction to the preliminary NA49 results. The introduction of a string clustering mechanism (Firecracker Model) leads to a further, significant increase of pT fluctuations for nucleus-nucleus collisions. Secondary hadronic interactions, as implemented in LUCIAE, cause only a small reduction of pT fluctuations

Net charge fluctuation and string fragmentation

We present simulation results of net charge fluctuation in $Au+Au$ collisions at $\sqrt{s_{nn}}$=130 GeV from a dynamic model, JPCIAE. The calculations are done for the quark-gluon phase before hadronization, the pion gas, the resonance pion gas from $\rho$ and $\omega$ decays and so on. The simulations of the charge fluctuation show that the discrepancy exists between the dynamic model and the thermal model for a pion gas and a resonance pion gas from $\rho$ and $\omega$ decays while the simulated charge fluctuation of the quark-gluon phase is close to the thermal model prediction. JPCIAE results of net charge fluctuation in the hardonic phase are nearly 4-5 times larger than one for the quark-gluon phase, which implies that the charge fluctuation in the quark-gluon phase may not survive the hadronization (string fragmentation) as implemented in JPCIAE.Comment: 9 pages, 3 figure