Hyaluronidase of Bloodsucking Insects and Its Enhancing Effect on Leishmania Infection in Mice

Hyaluronidases are enzymes degrading the extracellular matrix of vertebrates. Bloodsucking insects use them to cleave the skin of the host, enlarge the feeding lesion and acquire the blood meal. In addition, resulting fragments of extracellular matrix modulate local immune response of the host, which may positively affect transmission of vector-borne diseases, including leishmaniasis. Leishmaniases are diseases with a wide spectrum of clinical forms, from a relatively mild cutaneous affection to life-threatening visceral disease. Their causative agents, protozoans of the genus Leishmania, are transmitted by phlebotomine sand flies. Sand fly saliva was described to enhance Leishmania infection, but the information about molecules responsible for this exacerbating effect is still very limited. In the present work we demonstrated hyaluronidase activity in salivary glands of various Diptera and in fleas. In addition, we showed that hyaluronidase exacerbates Leishmania lesions in mice and propose that salivary hyaluronidase may facilitate the spread of other vector-borne microorganisms

Lyapunov spectrum of asymptotically sub-additive potentials

For general asymptotically sub-additive potentials (resp. asymptotically additive potentials) on general topological dynamical systems, we establish some variational relations between the topological entropy of the level sets of Lyapunov exponents, measure-theoretic entropies and topological pressures in this general situation. Most of our results are obtained without the assumption of the existence of unique equilibrium measures or the differentiability of pressure functions. Some examples are constructed to illustrate the irregularity and the complexity of multifractal behaviors in the sub-additive case and in the case that the entropy map that is not upper-semi continuous.Comment: 44 page

Stability in antigenic reactivity of the major outer surface protein, OspA, in borrelia burgdorferi, during persistent infection in Syrian hamsters

The spirochete Borrelia burgdorferi is the causative agent of Lyme disease, a multisystem disorder that can cause a variety of disorders in susceptible mammalian hosts. The immune response of infected mammals, including humans, is ineffective in clearing B. burgdorferi as demonstrated by the ability to reisolate the spirochete from naturally and experimentally infected hosts after extended periods of time. Recent evidence suggests that this pathogen evades the immune response in part through changes in antigenic reactivity.The purpose of this study was to determine if outer surface protein A (OspA) of B. burqdorferi varies in the course of infection in Syrian hamsters and thus potentially plays a role in evading the host immune response. To assess the degree of change, differences in the binding of a murine monoclonal antibody (H5332) were measured using IFA and ELISA techniques over a 9-week period of time.Results of this study suggest that OspA is persistently expressed in infected Syrian hamsters for at least 9-weeks. Moreover, this protein, or at least the epitope that H5332 binds with, is stably expressed. These results indicate OspA, or at least the epitope of OspA that I probed, does not appear to contribute to the evasive mechanisms of 8. burgdorferi in Syrian hamsters.Thesis (M.S.)Department of Biolog

Grundprobleme der Systemtransformation aus institutionenoekonomischer Perspektive

Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel W 929 (96.09) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Psychological Stress and the Cutaneous Immune Response: Roles of the HPA Axis and the Sympathetic Nervous System in Atopic Dermatitis and Psoriasis

Psychological stress, an evolutionary adaptation to the fight-or-flight response, triggers a number of physiological responses that can be deleterious under some circumstances. Stress signals activate the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system. Elements derived from those systems (e.g., cortisol, catecholamines and neuropeptides) can impact the immune system and possible disease states. Skin provides a first line of defense against many environmental insults. A number of investigations have indicated that the skin is especially sensitive to psychological stress, and experimental evidence shows that the cutaneous innate and adaptive immune systems are affected by stressors. For example, psychological stress has been shown to reduce recovery time of the stratum corneum barrier after its removal (innate immunity) and alters antigen presentation by epidermal Langerhans cells (adaptive immunity). Moreover, psychological stress may trigger or exacerbate immune mediated dermatological disorders. Understanding how the activity of the psyche-nervous -immune system axis impinges on skin diseases may facilitate coordinated treatment strategies between dermatologists and psychiatrists. Herein, we will review the roles of the HPA axis and the sympathetic nervous system on the cutaneous immune response. We will selectively highlight how the interplay between psychological stress and the immune system affects atopic dermatitis and psoriasis