The Influence of Prednisolone (PRED) and Methotrexate (MTX) on the Cell and Connective Tissue Content of Subcutaneously Implanted Polyurethane Sponges in Rats

Findings indicate that prednislone and methotrexate have profound effects on the cellular events of acute and chronic inflammation, and influence the synthesis or degradation of connective tissue macromolecules at certain stages of the inflammatory process

A sociologist teaches history: some epistemological and pedagogical reflections

This article discusses the concept of ‘historical sociology’ in relation to the teaching of a module on an undergraduate degree in Education Studies at a university in the United Kingdom. The module examines the history of education policy in England from 1870 until the present day. Drawing upon comparisons with Social Foundations of Education programs in the United States, I examine some key epistemological and pedagogical issues raised by the inter-disciplinary approach to teaching and learning followed within the module in which we combine historical and sociological perspectives as a means to understand the evolution of the English education system. In particular, using Bernstein’s concept of the pedagogic device as an analytical framework, I consider the epistemological congruence of sociology and history as the contributory disciplines of the undergraduate module. From a discussion of the concept of historical sociology, I conclude that although sociology and history are distinct subjects, they share a large amount of analytical ground which thus facilitates the inter-disciplinary approach pursued within the module. Following that, I examine some pedagogical issues that have arisen in my experience of teaching upon the module and I discuss how I have addressed these. I conclude the article by making comparisons to relevant examples from pedagogical practices in Social Foundations of Education programs in the United States

Importance of extracellular divalent cations to polarisation of polymorphonuclear leukocytes induced by plasma

The roles of extracellular calcium and magnesium ions in the polarisation of human peripheral blood polymorphonuclear leukocytes (PMN) induced by autologous fresh heparinised plasma were investigated by studying the effects of 5 mM chelators of divalent cations [ethylenediamine tetra-acetic acid (EDTA), ethylenebis-(oxyethylene-nitrilo)-tetra-acetic acid (EGTA) or disodium hydrogen citrate]. In addition, the effects of a blocker of membrane calcium channels (verapamil) were studied. Polarisation of PMN suspended in plasma (84.1 ± 11.9%) was reduced by each chelating agent over 30 min (to 20.0 ± 15.6% by EDTA, to 42.5 ± 19.3% by EGTA and to 29.4 ± 22.9% by citrate). Polarisation of PMN suspended in plasma treated with EDTA or EGTA was restored by inclusion of equimolar additional Ca2+ ions, and in plasma treated with EDTA, EGTA or citrate, by equimolar additional Mg2+ ions. Additional Mg2+ had no effect on the spherical shape of PMN in Hanks' solution and additional cations had no effects on the polarisation of PMN induced by fMLP. Cells rendered spherical by each chelating agent in plasma for 30 min retained their ability to polarise on addition of fMLP to the plasma-chelator medium. Verapamil (10-4 M) markedly reduced polarisation in plasma (to 52 ± 11.3%) but the same drug (10-5 M) had no such effect. In contrast to the polarisation of cells in plasma, the polarisation response of PMN to N-formyl-methionyl-leucyl-phenylalanine (fMLP, 10-8 M) in bufferred Hanks' solution was not affected by any of the chelating agents or by verapamil, even in high concentration. These results indicate that extracellular divalent cations are necessary for the polarisation of PMN suspended in autologous plasma and that the mechanism of polarisation of PMN in plasma may be different to that of polarisation induced by fMLP.</p

Proteoglycans synthesized by human polymorphonuclear leucocytes in vitro

Polymorphonuclear leucocytes (PMN) were assessed in vitro for their ability to synthesize and secrete proteoglycans. The PMN were isolated from human peripheral blood and were found to contain 35S)-sulfate, significant quantities of 35S-labelled macromolecules were detected both within the culture medium and cells. Although the PMN preparations contained some platelets (approximately five platelets: one PMN), culture of platelets alone did not result in the detection of any 35S-labelled macromolecules in either the medium or platelets 35S/3H-labelled macromolecules from the PMN cultures were identified as proteoglycans on the basis of their degradation by papain, alkaline sodium borohydride, chondroitinase ACII, chondroitinase ABC and nitrous acid. The labelled proteoglycans isolated from the medium and cells eluted from Sepharose CL-4B with a K(av) of 0.63; this indicated a small size compared with many other proteoglycans. The glucosaminoglycans associated with the proteoglycans were identified as heparan sulfate, chondroitin sulfate and dermatan sulfate, with chondroitin sulfate being the principal component. The average molecular weight of the glycosaminoglycans was determined to be 16000. Therefore, the data from this study demonstrate the ability of human PMN to synthesize and secrete proteoglycans in vitro which appear to differ from those synthesized by mesenchymal cells with respect to molecular size and glycosaminoglycan composition.</p

Effects of plasma proteins on the adhesion, spreading, polarization in suspension, random motility and chemotaxis of neutrophil leukocytes on polycarbonate (Nuclepore) filtration membrane

The effects on adhesion, spreading, polarization in suspension, random motility and chemotaxis to N-formyl-methionyl-leucyl-phenylalanine (FMLP) of neutrophil leukocytes on polycarbonate (Nuclepore) membrane in the Boyden chamber of purified serum albumin, gamma globulin and fibrinogen, as well as of the Hanks'-soluble components of Cohn fractions III (beta and gamma globulins) and IV (albumin, alpha globulins and transferrin) of plasma proteins were tested in comparison to the corresponding effects of dilute fresh heparinized plasma. Serum albumin, fibrinogen and fibronectin inhibited adhesion of neutrophils, so that the spreading, random motility and chemotaxis of these cells could not be assessed in the presence of these proteins alone. These plasma proteins induced little or no polarization of the cells in suspension. Of the remaining preparations, gamma globulin promoted adhesion and excessive spreading and caused corresponding reduction of random motility and chemotaxis to FMLP of these cells. This plasma protein, even in low concentration, induced marked polarization of neutrophils in suspension. Both Cohn fractions III and IV supported adhesion and permitted random motility and chemotaxis to FMLP approximating that which occurs in dilute plasma. These fractions induced moderate polarization of cells in suspension. Addition of serum albumin or fibronection to the preparations of gamma globulin, or Cohn fractions III or IV did not alter the adhesion, random motility or chemotaxis of the neutrophils in these preparations. These results suggest that alpha and beta globulins, as well as gamma globulins are factors in plasma affecting adhesiveness and polarization of neutrophils and which provide for optimal motility and chemotaxis of these cells on solid substrata. Furthermore, for all pure preparations of proteins tested, induction of polarization of neutrophils appeared to be linked to promotion of adhesiveness.</p

Eosinophilic interleukin 5 (IL-5) transgenic mice: eosinophil activity and impaired clearance of Schistosoma mansoni

Article first published online: 31 OCT 2003Eosinophilia is a feature common to many invasive helminth infections and eosinophils are often considered to be effector cells in immunity to helminths. This study examined the possible influence of constituitive eosinophilia on the clearance of Schistosoma mansoni infections in mice. Eosinophils from interleukin-5 transgenic mice exhibit normal ultrastructure and function with regard to phagocytosis and killing of bacteria and responses to chemotactic stimuli. IL-5 transgenics and non-transgenic littermates were immunized once or four (hyperimmunization) times with irradiated cercariae of S. mansoni. Animals were challenged percutaneously with unirradiated cercariae one month after their last exposure to irradiated parasites. One month after challenge transgenic animals, whether unimmunized, vaccinated or hypervaccinated, carried significantly more liver-stage parasites than non-transgenic animals. These results suggest that although eosinophils from IL-5 transgenic mice are functional for a number of key parameters, large numbers of eosinophils and/or high levels of IL-5 may in some way impair clearance of S. mansoni. A re-evaluation of the roles of eosinophils and IL-5 in infections with this and other parasites may therefore be warranted.Lindsay A. Dent, Grant H. Munro, Karen P. Piper, Colin J. Sanderson, David A. Finlay, Rachel K. Dempster, Leon P. Bignold, Damien G. Harkin & Paul Haga