Detection of early changes in autoimmune T cell phenotype and function following intravenous administration of type II collagen in a TCR-transgenic model.

To study the phenotypic and functional changes in naive type II collagen (CII)-specific autoimmune T cells following a tolerogenic signal, a TCR-transgenic (Tg) mouse model of collagen-induced arthritis was developed. These Tg mice express an I-A(q)-restricted CII (260-267)-specific TCR that confers severe accelerated autoimmune arthritis following immunization with CII. Despite the fact that >90% of the alphabeta T cells express the Tg, these mice can be rendered completely tolerant to the induction of arthritis by i.v. administration of 200 microg of CII. As early as 24 h after CII administration, CII-specific T cells demonstrated a decreased ability to proliferate in response to the CII immunodominant peptide and phenotypically altered the expression of L-selectin to CD62L(low) and of phagocytic glycoprotein-1 to CD44(high), expression levels consistent with the phenotype of memory T cells. In addition, they up-regulated the expression of the activation markers CD71 and CD69. Functionally, following tolerogenic stimulation, the CII-specific T cells produced similar levels of IL-2 in comparison to controls when challenged with CII peptide, however, by 48 h after exposure to tolerogen, IL-2 production dropped and was replaced by high levels of IL-10 and IL-4. Based on their production of Th2 cytokines, these data suggest that T regulatory cells expressing activation and memory markers are induced by the tolerogen and may exert their influence via cytokines to protect the animals from the induction of arthritis.     

Configurational statistics of 1,6-linked glycans

We have calculated the unperturbed dimensions of some 1,6-linked glycans by regarding the homopolymer as a ‘copolymer’ in which the different ‘comonomers’ are conformers characterized by the dihedral angle about the C5C6 bond.We find that the characteristic ratio is small (e.g. for the α-glucan it is about 3·3 to 3·4). From the results of some model calculations in which the dihedral angle about the C5C6 bond is fixed, we argue that these low values arise from bonding geometry effects, which are at least as important as the additional conformational freedom from rotation about the C5C6 bond.     

Nitrate reductase activity (in vivo and in vitro) of ditelosomic stocks of wheat (Triticum aestivum L.)

The nitrate reductase activities (NRA) of 31 ditelosomic stocks were compared with that of the control plant [Chinese Spring (CS) euploid], using in vivo and in vitro assay procedures that had been optimized with respect to the euploid. Fourteen stocks exhibited significant differences in in vivo NRA from that of the euploid; the effect of removal of a chromosome arm was always to increase NRA. Eight of these stocks showed similar effects in vitro, although in three, a casein-sensitive factor had to be eliminated before the difference was expressed. Homoeologous group effects were evident among ditelosomics of groups 2, 4, and 7, while for three chromosomes (2D, 7A, and 7B), removal of either arm resulted in a similar increase in NRA in vivo and probably in vitro.P. W. Jones was supported by a Science Research Council C.A.S.E. award with the Plant Breeding Institute, Cambridge, U.K.     

Empruthotrema kearni n. sp. and observations on Thaumatocotyle pseudodasybatis Hargis, 1955 (Monogenea: Monocotylidae) from the nasal fossae of Aetobatus narinari (Batiformes: Myliobatidae) from Moreton Bay,Queensland

Empruthotrema kearni n. sp. and Thaumatocotyle pseudodasybatis Hargis, 1955 (Monogenea: Monocotylidae) are reported from the nasal fossae of the spotted eagle ray, Aetobatus narinari Euphrasen, 1790, from Moreton Bay, Queensland, Australia. The discovery of E. kearni n. sp. is the first record of this genus from the Myliobatidae and a new geographical record for the genus. A comparison of T. pseudodasybatis from Florida, USA and from Queensland, Australia revealed morphometrical and microhabitat differences. The discovery of T. pseudodasybatis in Australian waters is a new geographical record for this species.     

Mammalian genome,volume 5, number 7, 1994, pp 416–423

Erratum

Mammalian genome, volume 5, number 7, 1994, pp 416–423     

Anti-immunoglobulin antisera used in an ELISA to detect antibodies in barramundi Lates calcarifer to Cryptocaryon irritans.

Immunoglobulins (Ig) in serum from barramundi vaccinated with bovine serum albumin (BSA) were purified by ammonium sulphate precipitation and affinity chromatography using BSA as the ligand. The BSA-binding activity of eluted putative Ig fractions was assessed by enzyme-linked immunosorbent assay (ELISA) before being pooled and characterised by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Double affinity purification did not improve the purity of the Ig preparation compared to single affinity purification. Barramundi Ig were injected into sheep to produce anti-Ig antisera which were assessed in an indirect ELISA as the secondary antibody to detect serum Ig in barramundi vaccinated with Cryptocaryon irritans theronts. Affinity-purified Ig induced a more specific reagent for use as secondary antibody in ELISA than did normal whole-barramundi sera. The heavy (H) chain of barramundi Ig had an apparent molecular weight of 70 kDa while that of the light (L) chain was 27 kDa in SDS-PAGE studies. Under non-reducing conditions 2 putative populations of Ig were identified, at 768 and 210 kDa. The N-terminal sequence of the barramundi Ig H chain showed 78% homology with channel catfish Ictalurus punctatus Ig H chain sequence.     

Electrographic Waveform Structure Predicts Laminar Focus Location in a Model of Temporal Lobe Seizures In Vitro

Temporal lobe epilepsy is the most common form of partial-onset epilepsy and accounts for the majority of adult epilepsy cases in most countries. A critical role for the hippocampus (and to some extent amygdala) in the pathology of these epilepsies is clear, with selective removal of these regions almost as effective as temporal lobectomy in reducing subsequent seizure risk. However, there is debate about whether hippocampus is ‘victim’ or ‘perpetrator’: The structure is ideally placed to ‘broadcast’ epileptiform activity to a great many other brain regions, but removal often leaves epileptiform events still occurring in cortex, particularly in adjacent areas, and recruitment of the hippocampus into seizure-like activity has been shown to be difficult in clinically-relevant models. Using a very simple model of acute epileptiform activity with known, single primary pathology (GABA_A Receptor partial blockade), we track the onset and propagation of epileptiform events in hippocampus, parahippocampal areas and neocortex. In this model the hippocampus acts as a potential seizure focus for the majority of observed events. Events with hippocampal focus were far more readily propagated throughout parahippocampal areas and into neocortex than vice versa. The electrographic signature of events of hippocampal origin was significantly different to those of primary neocortical origin – a consequence of differential laminar activation. These data confirm the critical role of the hippocampus in epileptiform activity generation in the temporal lobe and suggest the morphology of non-invasive electrical recording of neocortical interictal events may be useful in confirming this role.