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At least 1,783 records · Page 99Linked to original sources
PubMed1999

HLA-DR polymorphism influences T-cell precursor frequencies to Epstein-Barr virus (EBV) gp110: implications for the association of HLA-DR antigens with rheumatoid arthritis.

To study whether HLA-DR haplotypes associated with susceptibility to develop rheumatoid arthritis (RA) may influence T-cell responses to the Epstein-Barr virus (EBV) gp110 (a protein of the late replicative cycle of EBV), we evaluated the frequency in peripheral blood of T cells capable to proliferate to EBV gp110 by direct limiting dilution analysis in 50 HLA-DR-typed healthy subjects. NVe found that HLA-DRB1*07, an allele associated with reduced risk to develop RA, is associated with the highest frequencies of T cells specific for gp110 in peripheral blood. In contrast, HLA-DRB1*0404, one of the susceptibility alleles is associated with the lowest frequencies of gp110 specific T cells. Finally, people expressing both HLA-DRB1*07 and HLA-DRB1*0404 display low precursor frequencies to EBV gp110.

Animals↗
PubMed1999

An assay for peptide binding to HLA-Cw*0102.

The assembly assay for peptide binding to class I major histocompatibility complex (MHC) molecules is based on the ability of peptides to stabilize MHC class I molecules synthesized by transporter associated with antigen processing (TAP)-deficient cell. The TAP-deficient cell line T2 has previously been used in the assembly assay to analyze peptide binding to HLA-A*0201 and -B*5101. In this study, we have extended this technique to assay for peptides binding to endogenous HLA-Cw*0102 molecules. We have analyzed the peptide binding of 20 peptides with primary anchor motifs for HLA-Cw*0102. One-third of the peptides analyzed bound with high affinity, half of the peptides examined did not bind, whereas the remaining peptides displayed intermediate binding activity. Interest in HLA-C molecules has increased significantly in recent years, since it has been shown that HLA-C molecules both can present peptides to cytotoxic T lymphocytes (CTL) and in addition are able to inhibit natural killer (NK)-mediated lysis.

Animals↗
PubMed2001

Haematopoietic progenitor cells from the common marmoset as targets of gene transduction by retroviral and adenoviral vectors.

To establish a new non-human primate model for human cytokine and gene therapy, we characterized lymphocytes and haematopoietic progenitor cells of the small New World monkey, the common marmoset. We first assessed the reactions of marmoset bone marrow (BM) and peripheral blood (PB) cells to mouse anti-human monoclonal antibodies (mAbs) for the purpose of isolating marmoset lymphocytes and haematopoietic progenitor cells. Both cell fractions stained with CD4 and CD8 mAbs were identified as lymphocytes by cell proliferation assay and morphological examination. Myeloid-specific mAbs such as CD14 and CD33 did not react with marmoset BM and PB cells. No available CD34 and c-kit mAbs could be used to purify the marmoset haematopoietic progenitor cells. Furthermore, we studied the in vitro transduction of the bacterial beta-galactosidase (LacZ) gene into CFU-GM derived from marmoset BM using retroviral and adenoviral vectors. The transduction efficiency was increased by using a mixed culture system consisting of marmoset BM stromal cells and retroviral producer cells. It was also possible to transduce LacZ gene into marmoset haematopoietic progenitor cells with adenoviral vectors as well as retroviral vectors. The percentage of adenovirally transduced LacZ-positive clusters was 15% at day 4 (multiplicity of infection=200), but only 1-2% at day 14. The differential use of viral vector systems is to be recommended in targeting different diseases. Our results suggested that marmoset BM progenitor cells were available to examine the transduction efficiency of various viral vectors in vitro.

Adenoviridae↗
PubMed2001

Non-human primate models of multiple sclerosis.

The phylogenetic proximity between non-human primate species and humans is reflected by a high degree of immunological similarity. Non-human primates therefore provide important experimental models for disorders in the human population that are caused by the immune system, such as autoimmune diseases. In this paper we describe non-human primate models of multiple sclerosis, a chronic inflammatory and demyelinating disease of the human central nervous system. While reviewing data from the literature and our own research we will discuss the unique role of such models in the research of basic disease mechanisms and the development of new therapies.

Animals↗
PubMed2003

Upregulation of immunoreactivity of endothelin-1 and alpha-SMA in PDL microvasculature following acute tooth loading: an immunohistochemical study in the marmoset.

OBJECTIVES: To test the hypothesis that a continuous mechanical tooth load would elevate immunoreactivity of endothelin-1 (ET-1) and alpha-smooth muscle actin (alpha-SMA) in the periodontal ligament (PDL) microvasculature. DESIGN: A randomized control study employing 1.5 h of loading to first molars. SETTING AND SAMPLE POPULATION: Orthodontic Research Laboratory, Dental School, Adelaide University. Four young adult, male marmoset monkeys were consecutively anaesthetized and treated. EXPERIMENTAL VARIABLE: An external telescoping frame applied a jaw closing load (120-200 g) transmitted occlusally, via a rubber pad, to randomly assigned mandibular left or right first molars. Contralateral molars were used as controls. OUTCOME MEASURE: Undemineralized, midsagittal, mandibular molar slices, approximately 150 microm thick were immunolabelled with ET-1 and alpha-SMA antibodies and examined in a confocal laser scanning microscope (CLSM) for vascular endothelium and smooth muscle immunolabelling. RESULTS: Three categories of post-capillary-sized venule endothelial cell immunolabelling occurred: endothelium labelled solely with ET-1; endothelium labelled solely with alpha-SMA; endothelium labelled with both ET-1 and alpha-SMA. In endothelial cells, the alpha-SMA showed a moderate cytoplasmic distribution with dense peripheral concentration. Loading increased arteriole alpha-SMA actin labelling. CONCLUSION: Scattered expression of ET-1 is the default state in primate PDL endothelial cells. Increased antigenicity of endothelial cells to both ET-1 and alpha-SMA, and of arteriolar smooth muscle to alpha-SMA, is a response to shear and compression loads.

Actins↗
PubMed1996

Primate analogue of the Wisconsin Card Sorting Test: effects of excitotoxic lesions of the prefrontal cortex in the marmoset.

Using a primate analogue of the Wisconsin Card Sort Test, this study demonstrated, for the first time, that lesions of the prefrontal cortex in monkeys produce a qualitatively similar impairment in attentional set-shifting to that seen following prefrontal cortical damage in humans. Although damage to the prefrontal cortex did not disrupt the ability of marmosets, a New World monkey, to maintain an attentional set, it did disrupt their ability to shift an attentional set. It also impaired their performance on discrimination reversal, object retrieval, and spatial delayed response, consistent with the effects of prefrontal damage in Old World monkeys. Comparison of the cognitive processes underlying discrimination reversal, object retrieval, and attentional set-shifting reveals the various types of inhibitory control provided by the prefrontal cortex.

Animals↗
PubMed1999

Different effects on learning ability after injection of the cholinergic immunotoxin ME20.4IgG-saporin into the diagonal band of Broca, basal nucleus of Meynert, or both in monkeys.

Immunotoxic lesions of the diagonal band of Broca (VDB) in monkeys disrupted cholinergic input to the hippocampus, producing impaired learning of visuospatial conditional discriminations but not simple visual discriminations. Immunotoxic lesions of the basal nucleus of Meynert (NBM) deprived the cortex of most of its cholinergic input, producing impaired learning of simple visual discriminations but not visuospatial conditional discriminations. Combined lesions of the NBM + VDB resulted in impaired learning of both types of task. The impairment after NBM lesions ameliorated with time but could be reinstated by a low dose of the glutamate blocking drug MK801, which, at this dose, did not impair simple visual discrimination learning in normal monkeys. The cholinergic projections from the NBM and VDB may sustain the function of the glutamatergic pyramidal cell pathways within the cortex and hippocampus, respectively.

Analysis of Variance↗
PubMed2005

Mild topographical memory impairment following crossed unilateral lesions of the mediodorsal thalamic nucleus and the inferotemporal cortex.

Monkeys with crossed unilateral lesions of the dorsomedial thalamus and contralateral ablations of the inferotemporal cortex were mildly impaired on acquisition and retention of visual conditional tasks requiring the integration of information about objects and their positions in space. They were not impaired on other conditional and nonconditional tasks. This impairment pattern resembles, qualitatively, that found following crossed unilateral lesions of the anterior thalamus and the inferotemporal cortex or bilateral lesions of the anterior and mediodorsal thalamic nuclei. Although the flow of visual information from the inferotemporal cortex through the hippocampal-fornix-anterior thalamic circuit plays a major part in memory for objects in places, the flow of information between inferotemporal cortex and mediodorsal thalamus, possibly by means of the frontal cortex, also makes some contribution.

Animals↗
PubMed1996

Dissociation in prefrontal cortex of affective and attentional shifts.

The prefrontal cortex is implicated in such human characteristics as volition, planning, abstract reasoning and affect. Frontal-lobe damage can cause disinhibition such that the behaviour of a subject is guided by previously acquired responses that are inappropriate to the current situation. Here we demonstrate that disinhibition, or a loss of inhibitory control, can be selective for particular cognitive functions and that different regions of the prefrontal cortex provide inhibitory control in different aspects of cognitive processing. Thus, whereas damage to the lateral prefrontal cortex (Brodmann's area 9) in monkeys causes a loss of inhibitory control in attentional selection, damage to the orbito-frontal cortex in monkeys causes a loss of inhibitory control in 'affective' processing, thereby impairing the ability to alter behaviour in response to fluctuations in the emotional significance of stimuli. These findings not only support the view that the prefrontal cortex has multiple functions, but also provide evidence for the distribution of different cognitive functions within specific regions of prefrontal cortex.

Affect↗
PubMed1996

Primary cortical representation of sounds by the coordination of action-potential timing.

Cortical population coding could in principle rely on either the mean rate of neuronal action potentials, or the relative timing of action potentials, or both. When a single sensory stimulus drives many neurons to fire at elevated rates, the spikes of these neurons become tightly synchronized, which could be involved in 'binding' together individual firing-rate feature representations into a unified object percept. Here we demonstrate that the relative timing of cortical action potentials can signal stimulus features themselves, a function even more basic than feature grouping. Populations of neurons in the primary auditory cortex can coordinate the relative timing of their action potentials such that spikes occur closer together in time during continuous stimuli. In this way cortical neurons can signal stimuli even when their firing rates do not change. Population coding based on relative spike timing can systemically signal stimulus features, it is topographically mapped, and it follows the stimulus time course even where mean firing rate does not.

Action Potentials↗
PubMed2001

Environmental enrichment for laboratory marmosets.

The authors report on using two environmental enrichment devices for marmosets, and suggest the design of five other devices that may be more successful in stimulating foraging or grooming behavior than the devices tested.

Animal Welfare↗