Conduction Block in the Peripheral Nervous System in Experimental Allergic Encephalomyelitis

Experimental Allergic Encephalomyelitis (EAE) has been widely studied as a model of multiple sclerosis, a central nervous system (CNS) disease of unknown aetiology. The clinical features of both EAE and multiple sclerosis provide the only guide to the progress and severity of these diseases, and are used to assess the response to treatment. In such comparisons the clinical features of EAE are assumed to be due to lesions in the CNS, but in this disease there is also histological evidence of damage to the peripheral nervous system (1-8). However, the functional consequences of such peripheral lesions have been entirely ignored. To examine this, we have studied nerve conduction in rabbits with EAE. We report here that most of the large diameter afferent fibres are blocked in the region of the dorsal root ganglion and at the dorsal root entry zone, thus accounting for the loss of tendon jerks and also, through the severe loss of proprioceptive information, the ataxia of thse animals. We conclude that whenever clinical comparisons are made between EAE and multiple sclerosis, the pathophysiology associated with histological damage of the peripheral nervous system must be taken into account

The Pathophysiology of Acute Experimental Allergic Encephalomyelitis in the Rabbit

Clinical, histological and electrophysiological studies were performed on rabbits with acute experimental allergic encephalomyelitis (EAE). The clinical features were similar to those previously described, with the notable exception of the new findings of areflexia, respiratory slowing and hypothermia. The histological findings were also similar to those previously reported, with inflammatory demyelinating lesions both in the central and peripheral nervous system, especially the dorsal root ganglia. Electrophysiological studies performed one to nine days after the onset of neurological signs demonstrated conduction block in a high proportion of the large diameter afferents in the lumbosacral and thoracic dorsal root ganglia. Single fibre studies with spike-triggered averaging confirmed the conduction block in the dorsal root ganglia. That the conduction block was due to demyelination was indicated by slowing of conduction in large diameter fibres, normal conduction in unmyelinated fibres and the specific effects of temperature and of the potassium channel blocking agent, 4-aminopyridine. These conduction abnormalities in the peripheral nervous system, focused on the dorsal root ganglia, account for the postural disturbance, hypotonia, ataxia and areflexia in rabbits with EAE. Such conduction block is likely to mask the expression of any lesions of the central nervous system that alone could produce similar signs. The implications of these findings for the human demyelinating diseases are discussed

Land Management Decisions and Agricultural Productivity in the Hillsides of Honduras

Increasing land degradation and concomitant low agricultural productivity are important determinants of rural poverty in the hillside areas of Honduras. Using data at the levels of the farm household, parcel and plot, we develop an econometric modeling framework to analyze land management decisions and their impact on crop productivity. Our econometric model allows for endogenous household decisions regarding livelihood strategy choice, use of labor and external inputs, and participation in organizations. We found support for the inverse farm size-land productivity relationship which suggests that improved land access could increase total crop production. Land tenure has no impact on crop productivity, but adoption of soil conservation practices is higher on owner-operated than leased plots. Ownership of machinery and equipment and livestock ownership both positively influence crop productivity. Education positively affects perennial crop productivity. The gender of the household head has no significant effect on crop productivity, but does influence some land management and input use decisions. Even though household participation in training programs and organizations has only limited effects on crop productivity, agricultural extension plays a key role in promoting adoption of soil conservation practices. Location assets have limited impacts on crop productivity but do influence land management decisions. Road density and better market access have a positive effect on perennial crop productivity. Population density has limited direct impact on crop productivity, though it may have indirect effects by affecting farm size and livelihood strategies.agricultural productivity, hillsides, Honduras, land management, soil conservation, Land Economics/Use, Productivity Analysis,

Optomechanical cooling of levitated spheres with doubly-resonant fields

Optomechanical cooling of levitated dielectric particles represents a promising new approach in the quest to cool small mechanical resonators towards their quantum ground state. We investigate two-mode cooling of levitated nanospheres in a self-trapping regime. We identify a rich structure of split sidebands (by a mechanism unrelated to usual strong-coupling effects) and strong cooling even when one mode is blue detuned. We show the best regimes occur when both optical fields cooperatively cool and trap the nanosphere, where cooling rates are over an order of magnitude faster compared to corresponding single-sideband cooling rates.Comment: 8 Pages, 7 figure

Microglia are more susceptible than macrophages to apoptosis in the central nervous system in experimental autoimmune Encephalomyelitis through a mechanism not involving Fas (CD95)

Morphological studies have shown that macrophages and microglia undergo apoptosis in the central nervous system (CNS) in acute experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. To assess the relative levels of macrophage and microglial apoptosis, and the molecular mechanisms involved in this process, we used three-colour flow cytometry to identify CD45lowCD11b/c+ microglial cells and CD45highCD11b/c+ macrophages in the inflammatory cells isolated from the spinal cords of Lewis rats 13 days after immunization with myelin basic protein (MBP) and complete Freund's adjuvant. Simultaneously, we analyzed the DNA content of these cell populations to assess the proportions of cells undergoing apoptosis and in different stages of the cell cycle or examined their expression of three apoptosis-regulating proteins, i.e. Fas (CD95), Fas ligand (FasL) and Bcl-2. Microglia were highly vulnerable to apoptosis and were over-represented in the apoptotic population. Macrophages were less susceptible to apoptosis than microglia and underwent mitosis more frequently than microglia. The different susceptibilities of microglia and macrophages to apoptosis did not appear to be due to variations in Fas, FasL or Bcl-2 expression, as the proportions of microglia and macrophages expressing these proteins were similar, and were relatively high. Furthermore, in contrast to T cell apoptosis, apoptosis of microglia/macrophages did not occur more frequently in cells expressing Fas or FasL, or less frequently in cells expressing Bcl-2. These results indicate that the apoptosis of microglia and CNS macrophages in EAE is not mediated through the Fas pathway, and that Bcl-2 expression does not protect them from apoptosis. Expression of FasL by macrophages and microglia may contribute to the pathogenesis and immunoregulation of EAE through interactions with Fas+ oligodendrocytes and Fas+ T cells. The high level of microglial apoptosis in EAE indicates that microglial apoptosis may be an important homeostatic mechanism for controlling the number of microglia in the CNS following microglial activation and proliferation

Antigen-Specific Down-Regulation of Myelin Basic Protein-Reactive T Cells During Spontaneous Recovery From Experimental Autoimmune Encephalomyelitis: Further Evidence of Apoptotic Deletion of Autoreactive T Cells in the Central Nervous System

Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats by the i.v. injection of 107 cloned V beta 8.2+ T cells specific for the 72-89 peptide of guinea pig myelin basic protein (MBP). Some animals were injected simultaneously with 107 cloned T cells specific for ovalbumin (OVA). Lymphocytes were isolated from the spinal cord and from the peripheral lymphoid organs of these rats and the frequencies of MBP-peptide-specific or OVA-specific proliferating cells were estimated by limiting dilution analysis at different times after cell transfer. The frequencies of cells specific for MBP_72-89 or OVA in the spinal cord were highest 5 days after cell transfer (MBP_72-89, 1 in 1149; OVA, 1 in 1116). On day 7, when the rats were recovering, the frequency of cells specific for MBP_72-89 in the spinal cord fell dramatically t

The Internationalists: Australian writers and contemporary Greece

The expatriate Europeans, Australians, New Zealanders and Americans who lived on the Greek island of Hydra in the 1950s and ’60s were a mix of fiction writers, poets, musicians, painters, journalists and photographers. Politically, many of them would have described themselves as internationalists. George Johnston wrote his novel My Brother Jack (1964) while he and Charmian Clift lived on Hydra, and with it he said he rediscovered Australia. The contemporary Australian writers Susan Johnson and Meaghan Delahunt have each been inspired in their own work by the fiction and memoir of Johnston and Clift. Both Johnson and Delahunt have spent long periods of their lives as expatriates themselves, living in the UK and other parts of Europe. In spite of the achievements of Johnson and Delahunt as novelists, their writing has been largely overlooked by critics. This article examines their work in relation to expatriatism, internationalism and the politics of contemporary Europe. The article examines Susan Johnson’s reimagining of the lives of George Johnston and Charmian Clift in The Broken Book (2004) in 2019, 50 years after Clift’s death. It also explores Delahunt’s To the Island (2011), which is set on Naxos. The essay articulates the ways in which Johnson and Delahunt have internationalised Australian literature as a direct result of their expatriate experiences.Anne Pende

Effects of Cyclosporin A Treatment on Clinical Course and Inflammatory Cell Apoptosis in Experimental Autoimmune Encephalomyelitis Induced in Lewis Rats by Inoculation with Myelin Basic Protein

Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats by inoculation with myelin basic protein (MBP) and adjuvants. Rats were treated with second daily injections of saline or cyclosporin A (CsA) from the day of inoculation. Saline-treated rats had an acute episode of disease followed by clinical recovery. Rats treated with CsA 16 or 32 mg/kg had minimal signs of EAE at the usual time after inoculation, but developed signs of disease after treatment was ceased. Rats treated with CsA 8 mg/kg had a delayed first episode of disease and then developed a relapsing or a chronic persistent course of disease. CsA 4 mg/kg delayed the onset of disease. To study the effects of CsA on the inflammatory infiltrate, cells were extracted from the spinal cords of rats with EAE, 16 h after a single injection of CsA or saline. Extracted cells were labelled with antibodies to T cells, CD11b/c (macrophages/microglia), CD95 (Fas) and Fas ligand. CsA 4 mg/kg did not alter the composition of the inflammatory infiltrate. Treatment with higher single doses of CsA caused a dose-dependent decline in the percentage of T cell receptor (TCR)alpha beta+ cells in the inflammatory infiltrate. All doses of CsA caused a significant increase in the number and percentage of cells that were apoptotic. CsA treatment caused an increase in the percentages of CD5+ and TCR alpha beta+ cells that were apoptotic. There was a decline in the percentage of apoptotic T cells that were V beta 8.2+, compared to the percentage of non-apoptotic T cells that were V beta 8.2+, in CsA treated rats compared to saline-treated controls. This suggests that, while CsA treatment caused a non-specific increase in the overall level of T cell apoptosis in the spinal cord, it abrogated the selective apoptosis of V beta 8.2+ encephalitogenic T cells that normally occurs during spontaneous recovery from acute EAE

Sustained personal contact: Recent Australian productions on tour in China

In 2012 Australia’s first ambassador to China, Stephen Fitzgerald, argued that Australians need a stretch of the imagination ‘to be able to imagine a different kind of relationship’ with China, one that is not merely transactional and commercial. Fitzgerald encouraged Australians to invest in the relationship in a way that we have with other important nations such as the UK and the US. He stressed the need for an ‘intensity of sustained personal contact’. The making of theatre is one of the ways in which sustained personal contact occurs, and a genuine cultural exchange. Between 2012 and 2020 at least a dozen Australian theatre companies have taken their work to China. Companies offering opera, ballet, spoken word drama, physical theatre, puppetry and children’s theatre have all toured or appeared at festivals, some of them offering productions over multiple years. This article draws on extensive first-hand accounts by participants interviewed by the author to explore the recent experiences of actors, directors and producers involved in three touring productions and their reception by Chinese audiences, against a backdrop of expanding access to, and increasing interest in Australian performance in the People’s Republic. Using a case study approach, the article examines the development and production of three diverse works and the extent of their adaptation for audiences in China. The case study productions include Saltbush, an immersive children’s theatre production from Insite Arts, Baba Yaga, a children’s play and co-production between Adelaide’s Windmill Theatre and Scotland’s Imaginate, and desert, 6.29pm, a play produced by the Red Stitch Actors’ Theatre, who were invited to perform at the Wuzhen Theatre Festival in 2018. The article considers the spaces of aesthetic transformation and intercultural connection afforded by the productions, the long-term investment in children’s theatre in South Australia that has enabled the international reach of several companies, the finely balanced economics of touring to China, and the sustained personal relationships between the touring companies and the individuals who operate the highly successful Shanghai-based presenting company, A.S.K (Art Space for Kids). It speculates about performance futures and collaborative opportunities between China and Australia at a time of strained relations.Anne Pende