Stephen Boyden

Bio: Stephen Boyden is an academic researcher from Australian National University. The author has contributed to research in topics: Ecosystem health & Conceptual framework. The author has an hindex of 6, co-authored 9 publications receiving 3010 citations.

The chemotactic effect of mixtures of antibody and antigen on polymorphonuclear leucocytes.

Abstract: An in vitro technique is described for assessing the chemotactic activity of soluble substances on motile cells. Antibody-antigen mixtures when incubated (37°C) in medium containing fresh (i.e. non-inactivated) normal rabbit serum exert a strong chemotactic effect on rabbit polymorphonuclear leucocytes. Results are described which indicate that, when antibody-antigen complexes are incubated (37°C) in fresh serum, a heat-stable (56°C) substance (or substances) is produced which acts directly as a chemotactic stimulus on the polymorphs. This heat-stable chemotactic substance is not produced when antibody-antigen complexes are incubated in serum which has been heated at 56°C for 30 minutes.

Natural antibodies and the immune response.

Abstract: Publisher Summary This chapter reviews the subject of natural antibodies by analyzing the experimental data that demonstrate their existence and characteristics in both invertebrates and vertebrates. Their actions are related to those of other serum constituents that also participate in the serological recognition of foreign substances. The still unanswered questions of the origin of natural antibodies and their possible role in the recognition of antigens and in the initiation of the immune response are discussed in the chapter. The question proposed in the chapter is whether the postulated recognition factors of the immune system are detectable in serum or are attached to certain cells as natural antibodies. The available data is not sufficient to allow an answer to this question, it nevertheless seems of interest to discuss to what extent these data are compatible with the notion that some natural antibodies may represent the recognition factors of acquired immunity. The chapter also discusses the occurrence, origin, and characteristics (specificity and avidity, heat stability, electrophoretic properties, and molecular weight) of the natural antibodies.

Autoimmunity and inflammation.

Abstract: THE local humoral and cellular events which occur in the skin following cell injury are very similar to those which follow the intradermal injection of soluble antigen in an immunized animal which has antibodies in its circulation. In both cases there is an immediate increase in the permeability of the small blood vessels, adherence of leucocytes to the vessel walls and migration of leucocytes into the surrounding tissue1–3. The usual explanation of this similarity is that the antibody–antigen reaction causes a certain degree of cell damage, with consequent release of the pharmacologically active substances which are also liberated following injury to cells from other causes. In this communication an alternative, and in fact opposite, view is put forward. It is suggested that the reaction due to cell injury is similar to that due to antibody–antigen interaction because damage to cells causes the local formation of antibody–antigen complexes.

The environment and human health.

Abstract: A S::IIALL BUT GROWING SECTION of our community is coming to appreciate that trends in the relationship between human society and the total environment constitute a serious threat to the survival of civilization and mankind. Of course, throughout prehistory and history, human groups have-from time to time-been faced with environmental threats, and some of these groups have survived, while others have succumbed. In the past, however, there have always been other groups elsewhere to multiply and replace those that have succumbed. An essential difference today is that, for the fir-st time in biological history, the whole human species is, in terms of the global ecological changes that are taking place, a single group; and if this single group does not succeed in overcoming the threats, there will be this time no other groups to replace it and thus to keep the species going. To state the problem in more positive terms, the double task of bringing under control the galloping technodemographic processes which threaten the integrity of the biosphere, and of maintaining and improving the quality of life for mankind the world over, represents by far the greatest challenge of all time to the collective intelligence of the human species. That the concern about the total environmental predicament is now shared by at least some members of the medical profession is reflected in the fact that a section of this Congress is to be devoted to aspects of the problem. I have been asked to speak on \"The Effect of the Environment on Man's Diseases\". This is something of a tall order, for, as I understand Hippocrates recognized, the health-disease .pattern in any community at any time is largely a function of the quality of the total environment-physical, chemical, biological and social. Perhaps it was the intention of the oganizers of the meeting that I should discuss fairly specifically the biologically-determined effects on human beings of certain rather topical environmental changes, such as air pollution, water pollution, contamination of foodstuffs with pesticides, crowding in urban communities and so on.

‘Biosensitive’ cities — a conceptual framework for integrative understanding of the health of people and planetary ecosystems

Abstract: Urban sustainability research, despite rapid growth in research activity in recent years, still lacks integrative conceptual and methodological approaches that account for the full spectrum of urban processes and variables that determine human and ecosystem health and natural resource use. Once developed, such approaches would allow assessment of cities and urban policy and planning options in terms of the extent to which they satisfy the biologically determined health needs of people and maintain the integrity of the ecosystems on which cities depend. Integrated analysis and assessment of cities with regard to human health, ecosystem integrity and resource use would build on evolutionary and historical perspectives, and assist in understanding current environmental and health impacts of urbanism and options for the future.

The present and future role of microfluidics in biomedical research

Abstract: Microfluidics, a technology characterized by the engineered manipulation of fluids at the submillimetre scale, has shown considerable promise for improving diagnostics and biology research. Certain properties of microfluidic technologies, such as rapid sample processing and the precise control of fluids in an assay, have made them attractive candidates to replace traditional experimental approaches. Here we analyse the progress made by lab-on-a-chip microtechnologies in recent years, and discuss the clinical and research areas in which they have made the greatest impact. We also suggest directions that biologists, engineers and clinicians can take to help this technology live up to its potential.

Leukocyte locomotion and chemotaxis. New methods for evaluation, and demonstration of a cell-derived chemotactic factor.

Abstract: Polymorphonuclear leukocyte (PMN) locomotion and chemotaxis have been evaluated by direct microscopic observation of individual cells in thin slide-cover slip preparations, and also by observations on populations of cells migrating into a Millipore filter. The direct microscopic method used the polarity of the locomoting PMNs (broad, advancing lamellipodium and knoblike constriction at the rear) to record the direction of movement. The Boyden chamber Millipore assay was made more reliable by following the front of cells advancing into the filter, rather than counting the number of cells on the lower filter surface. Special modifications of the Millipore assay were necessary in order to distinguish between influences on rate of locomotion and true chemotaxis. In both systems the results indicate that under certain conditions leukocytes, and in particular PMNs, release into the medium a factor stimulating locomotion and exerting chemotactic action on PMNs in the vicinity. This cell-derived factor appears not to require serum factors for its release or action.

The Molecular Biology of Leukocyte Chemoattractant Receptors

Abstract: Leukocytes migrate from the blood to sites of inflammation in response to locally produced chemoattractants that activate specific cell surface receptors. The primary structures of leukocyte receptors for N-formyl peptides, C5a, platelet-activating factor, and 8 of the 18 known human chemokines (interleukin-8 and related molecules) have been deduced from cloned cDNAs. All of these are seven-transmembrane-domain rhodopsin-like G protein-coupled receptors. Biochemical and molecular genetic analysis of the chemoattractant receptors indicates that the chemoattractants may have both broadly overlapping as well as specialized roles in the regulation of acute and chronic inflammation. Interestingly, the chemokine receptors have functional homologues in human cytomegalovirus and Herpesvirus saimiri. Moreover, the Duffy antigen, which mediates invasion of erythrocytes by Plasmodium vivax, a major cause of malaria, is also a chemokine binding protein. These surprising developments suggest that in addition to leukocyte-mediated inflammation, the chemokines may also be involved in erythrocyte function and, through molecular mimicry, in microbial pathogenesis.

MIF is a pituitary-derived cytokine that potentiates lethal endotoxaemia

Abstract: Cytokines are critical in the often fatal cascade of events that cause septic shock. One regulatory system that is likely to be important in controlling inflammatory responses is the neuroendocrine axis. The pituitary, for example, is ideally situated to integrate central and peripheral stimuli, and initiates the increase in systemic glucocorticoids that accompanies host stress responses. To assess further the contribution of the pituitary to systemic inflammatory processes, we examined the secretory profile of cultured pituitary cells and whole pituitaries in vivo after stimulation with bacterial lipopolysaccharide (LPS). Here we identify macrophage migration inhibitory factor (MIF) as a major secreted protein release by anterior pituitary cells in response to LPS stimulation. Serum analysis of control, hypophysectomized and T-cell-deficient (nude) mice suggests that pituitary-derived MIF contributes to circulating MIF present in the post-acute phase of endotoxaemia. Recombinant murine MIF greatly enhances lethality when co-injected with LPS and anti-MIF antibody confers full protection against lethal endotoxaemia. We conclude that MIF plays a central role in the toxic response to endotoxaemia and possibly septic shock.

A 48-well micro chemotaxis assembly for rapid and accurate measurement of leukocyte migration

Abstract: We designed a 48-well chemotaxis chamber to minimize manipulation time and amount of material required by the larger blindwell or Boyden chemotaxis chamber. Cell and chemoattractant dose-response curves showed that results were comparable to our better than those obtained with blindwell chambers. The volume of chemoattractant per well is 25 microliter; the number of cells can be as low as 10,000. The time needed for setting up this multiwell unit and for staining the membrane filter sheet is negligible. Combined with the use of an image analyzer to count the number of migrated cells, the method is suitable for clinical research on the functional state of monocytes in large groups of patients.