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Biomedical subjects

C C Bernard

Publications and source records attributed to C C Bernard.

At least 91 records · Page 5Linked to original sources
PubMed1986

Solubilization and characterization of a low-affinity histamine-binding site on human blood mononuclear cells.

The extract of human peripheral blood lymphocytes and monocytes treated with Triton X-100, in direct- and competitive-binding studies, with 10(-6)-10(-2) M [14C]histamine contained a low-affinity binding site whose dissociation constant (Kd 1.8 X 10(-4) M) was commensurate with the concns of histamine (10(-6)-10(-3) M) that result from mast cell and basophil degranulation. Binding was enhanced by millimolar concns of divalent cations and by raising the incubation temp from 4 to 37 degrees C. It was inhibited by trypsin, EDTA, agents interacting with thiol groups, and by Triton X-100 concns greater than 0.2%. Thus a low-affinity histamine receptor that maintains its ligand-binding properties after solubilization from the cell surface was identified.

Binding, Competitive↗
PubMed1986

Evolutionary divergence in the structure of myelin basic protein: comparison of chondrichthye basic proteins with those from higher vertebrates.

A basic protein has been purified from the CNS myelin of the gummy shark (Mustelus antarticus). Electroblotting was used to examine the capacity of rabbit antisera raised against this electrophoretically pure protein to recognize myelin basic protein from higher vertebrates. The antisera bound to two shark proteins including the original polypeptide antigen and to chicken, bovine, and human myelin basic proteins. Thus, the shark protein appeared to possess antigenic determinants that have been retained through evolutionary divergence of these proteins. Whereas bovine basic protein caused experimental allergic encephalomyelitis in guinea pigs, animals that received injections of the shark protein showed neither clinical nor histological signs of this disease. However, tests for delayed-type hypersensitivity and for Arthus reaction following injection with the shark protein revealed a T-cell-mediated response to this antigen and substantial cross-reactivity with higher vertebrate basic proteins. Analysis of the amino acid composition of the shark protein, and comparison of its tryptic peptide map with that of the bovine protein, revealed substantial changes in the amino acid sequence. Although the shark protein has some antigenic determinants in common with the proteins from higher vertebrates, it appears that much of the structure differs.

Amino Acids↗
PubMed1986

Quantitative electroimmunoblotting study of the calcium-activated neutral protease in human myelin.

Degradation of myelin basic protein (MBP) in human man myelin was monitored by electroimmunoblotting. Problems of variation between, as well as within, electroimmunoblots were overcome by the introduction of an internal standard in each sample, thus allowing reproducible quantification of MBP. The Ca2+-dependent protease acting on MBP was active at endogenous levels of Ca2+ (congruent to 300 micrograms/g myelin) and was inhibited in the presence of Ca2+ chelators. Extensive degradation of MBP occurred rapidly in the presence of added Ca2+, reaching a plateau after a 1 h incubation (80-85% degradation). The proteolytic activity was not enhanced in the presence of 2-mercaptoethanol. It was most active at neutral pH and at temperatures approaching physiological conditions. No difference was observed between proteolytic activities of control and multiple sclerotic myelin. It is suggested that fluctuations in the accessibility of free Ca2+ to the protease may lead to the regulation of Ca2+-activated myelinolysis.

Brain↗
PubMed1985

Macrophage procoagulant activity as a measure of cell-mediated immunity to P2 protein of peripheral nerves in the Guillain-Barré syndrome.

Cell-mediated and humoral immunity to purified nerve proteins has been assessed in GBS patients and compared with that of patients with other neurological diseases and healthy controls. A strong and specific cell-mediated response to the neuritogenic basic protein P2 occurred in 13/16 GBS patients tested. Extremely low levels of P2 (0.01 micrograms/culture) induced monocyte/macrophage procoagulant activity (MPCA) on peripheral blood mononuclear cells (PBM) from GBS patients (P = 0.007) whereas higher concentrations (2 micrograms/culture) of myelin basic protein (MBP) and sciatic nerve myelin (SNM) were required to stimulate similar levels of activity. These concentrations of nerve antigens failed to induce significant MPCA on peripheral blood mononuclear cells of patients with other neuropathies or healthy controls. Lipopolysaccharide, a non-specific stimulant of macrophage procoagulant activity, induced similar procoagulant levels on PBM from each group. The MPCA assay was a sensitive, quantitative and specific indicator of cell-mediated immunity to the neuritogenic peptide, P2 in GBS patients. Serum antibodies to P2, P0 and SNM were detected by a sensitive solid-phase radioimmunoassay. Naturally occurring antibodies to peripheral nerve antigens were observed in sera of healthy subjects and these levels were not significantly different from patients with GBS or those with other neuropathies. Our results indicate that the autoimmune cell-mediated response to the neuritogenic peptide P2 plays a major role in the pathogenesis of GBS.

Adolescent↗
PubMed1985

Concomitant detection of changes in myelin basic protein and permeability of blood-spinal cord barrier in acute experimental autoimmune encephalomyelitis by electroimmunoblotting.

An electroimmunoblotting technique was used with a monoclonal antibody to myelin basic protein (MBP) to assess demyelination in 3 defined regions of the spinal cord in rats with acute experimental autoimmune encephalomyelitis (EAE). A slight loss in MBP was detected only in the sacrococcygeal region of the spinal cord after the onset of clinical signs. In all 3 spinal cord regions studied, significantly elevated levels of albumin and IgG were detected during the course of EAE by the same technique. At the onset of clinical signs, the levels of IgG and albumin were highest in the more caudal regions of the spinal cord. As the clinical signs became more severe, IgG and albumin levels increased in the more cranial regions of the spinal cord. These changes thus correlated with the ascending progression of clinical signs typical of EAE in rats. These results provided added evidence that in rats affected with acute EAE, the clinical signs occur independently of demyelination and coincide with vasogenic edema.

Albumins↗
PubMed1984

Detection of various forms of brain myelin basic protein in vertebrates by electroimmunoblotting.

An electroimmunoblot technique was used to detect various forms of myelin basic protein (MBP) in brain homogenates of 14 vertebrate species. Three antibodies were used to probe the immunoblots: a monoclonal anti-human MPB reacting with an antigenic determinant located at amino acid residues 131 to 136; a polyclonal anti-human MBP and a polyclonal anti-chicken MBP. Because no processing of the tissue is required prior to electrophoresis, in vitro artifacts are minimized. The 18.5 K form of MBP was present in all species except the shark. A 21.5 K MBP was observed in ovine, bovine, pig, rabbit, mouse, rat, monkey, but not in human, guinea pig, shark, toad and marsupial brains. A variant with a molecular weight between 17 K and 18 K was found in mouse, rat, bovine, human, monkey, pig, and chicken brains, and was the sole component in the shark brain. Marsupial brains had five or six forms of MBP between 14.5 K and 18.5 K.

Animals↗
PubMed1984

Elicitation of experimental allergic encephalomyelitis (EAE) in mice with the aid of pertussigen.

Pertussigen, one of the biologically active proteins from Bordetella pertussis, was found highly active as an adjuvant to promote the induction of experimental allergic encephalomyelitis (EAE) in (SJL X BALB/c)F1 mice that had received at the same time an injection of mouse spinal cord (MSC) homogenized in complete Freund's adjuvant containing 4 mg of Mycobacterium tuberculosis H37RA per milliliter (CFA-H37). In this system 2 mg of MSC induced EAE, but a dose of 4 mg was more effective. As little as 250 ng of pertussigen facilitated induction of EAE, and 400 ng uniformly did so. Pertussigen was most effective when given iv from 1 day before to 5 days after administration of MSC homogenized in CFA-H37, when a uniform and severe disease was induced 11-13 days after immunization. Pertussigen given as late as 20 days after MSC-CFA-H37 still precipitated a mild form of EAE which appeared 8-12 days after the injection of pertussigen. When pertussigen was given 5 days after immunization, a chronic, nonfatal type of EAE was induced, and this persisted for the entire 74 days of observation. Histologic findings in the brain and spinal cord 15 days after sensitization in mice which received pertussigen and developed EAE showed perivascular infiltrates consisting mainly of mononuclear cells.

Animals↗
PubMed1984

Susceptibility and resistance to experimental autoimmune encephalomyelitis and neuritis in the guinea pig correlate with the induction of procoagulant and anticoagulant activities.

Activation of macrophage procoagulant activity (MPCA) is involved in the manifestation of EAE and EAN in susceptible guinea pigs and provides a mechanism for the deposition of fibrin, which is a feature of histologic lesions of EAE. Peritoneal exudate cells (PEC) from susceptible (strain 13) guinea pigs immunized with either central or peripheral nervous tissue antigens produce procoagulant activity when incubated with the immunogen in vitro. The production of the procoagulant is quantitative and antigen-specific and is maximal at the time of clinical signs of the disease. After recovery, the production of procoagulant activity decreased. The MPCA test was able to discriminate the biochemical differences existing between chicken and mammalian peripheral nerve proteins, thus providing a quantitative and sensitive indicator of cell-mediated immunity in EAE and EAN. The autoimmune response to brain and nerve antigens in nonsusceptible (strain 2) guinea pigs was coincident with the antigen-specific production of a cell-bound anticoagulant activity by stimulated mononuclear cells. The production of anticoagulant activity followed the same sequence of time changes after immunization as that of the MPCA in susceptible guinea pigs, and high immunizing doses of nerve antigens induced high levels of anticoagulant activity. The same cells produced high levels of procoagulant when incubated with tuberculin or lipopolysaccharide. The recalcification time of normal plasma was prolonged by the anticoagulant, and the decreased clotting time of plasma induced by the procoagulant activity obtained by incubating sensitized strain 13 PEC with myelin basic protein was suppressed by the anticoagulant produced by culturing sensitized strain 2 PEC with myelin basic protein. Preliminary evidence indicates that the anticoagulant has properties similar to antithrombin III. The anticoagulant could play a role in the control of effector cell function, and therefore in recovery from clinical features of EAE and EAN in susceptible guinea pigs.

Animals↗
PubMed1984

Survival and tissue localization of xenogeneic human lymphocytes in hypothymic nude mice: observations in normal subjects and multiple sclerosis.

The feasibility of using the hypothymic nude mouse as a transfer system for the study of cellular autoimmunity, by injection and tracing of 51chromium (Cr) or fluorescein labelled lymphocytes from humans, allogeneic or syngeneic mice was investigated. The localization of the injected cells was studied by radioisotopic counting or microscopy. For mouse cells there was better survival of syngeneic than allogeneic cells, and the pattern of distribution of injected mouse lymphocytes differed markedly from that of xenogeneic human lymphocytes. Thus, the lymph nodes and spleen were the predominant sites of localization of transferred syngeneic (BALB/c) lymphocytes, indicative of long recirculation of these cells, whereas the liver was the predominant site of localization of transferred human lymphocytes, and there was no evidence for recirculation of these cells. In studies on patients with multiple sclerosis, lymphocytes did not localize in neural tissue. The data indicate that the nude mouse is unlikely to be useful for the study of the tissue distribution of dispersed xenogeneic (human) lymphocytes.

Adult↗
PubMed1983

Copper salicylate as an anti-inflammatory and analgesic agent in arthritic rats.

Recent research indicates that endogenous copper is involved in anti-inflammatory and tissue repair processes. Of interest also is the analgesic efficacy of Cu complexes, since rheumatoid arthritis and similar inflammatory conditions are extremely painful. In pilot experiments, arthritic rats failed to increase voluntarily their rate of drinking a 5 mg/ml solution of copper salicylate (Cu Sal). The data from the experiment reported here showed that a forced oral dose of Cu Sal calculated at 200 mg/kg body weight significantly reduced sensitivity to mechanical pressure in less than 30 minutes but more than 15 minutes. The analgesic effect of the Cu Sal was greater for arthritic than for non-arthritic rats, suggesting that two types of analgesia are involved. First, it produces a direct analgesic effect which works irrespective of the presence of inflammation. Second, it appears to have an indirect analgesic effect due to reduction of inflammatory hyperalgesia. It was also found that Cu Sal administered orally reduces inflammation in rats with adjuvant arthritis. In summary, the results from this experiment demonstrate that Cu Sal has specific and general analgesic properties and anti-inflammatory potential.

Administration, Oral↗
PubMed1983

Flow microfluorometry detects IgM autoantibody to oligodendrocytes in multiple sclerosis.

Freshly isolated canine oligodendrocytes were reacted by indirect membrane immunofluorescence with 44 sera from patients with multiple sclerosis (MS). Using analysis by flow microfluorometry (FMF), we found significant IgM antibody binding to the surfaces of oligodendrocytes in the MS sera. The fluorescence intensity of cell surface reactions for MS sera (F.I. greater than 40 = 37.2 +/- 21.34%) was significantly different (P less than 0.001) to that for 53 sera from normal subjects (10.0 +/- 8.97%), 15 sera from patients with Murray Valley encephalitis (6.18 +/- 5.3%), 22 with brain tumours (6.18 +/- 5.3%), 25 with SLE (13.42 +/- 11.65%), 7 with GBS (9.77 +/- 3.9%) and 7 miscellaneous neurological disorders (6.87 +/- 3.04%). Cell surface binding was restricted to oligodendrocytes and was absorbed out by oligodendrocytes but not by liver cells or kidney cells. Oligodendrocytes were identified by conventional histology, phase-contrast optics, electron microscopy (EM) and by cell surface reactions with anti-galactocerebroside, a specific immunocytological marker for oligodendrocytes. A cell sort of the single 0 degree FMF scatter peak followed by EM examination confirmed that the reactive cells consisted exclusively of oligodendrocytes. Viability of oligodendrocytes before and after the staining reactions, was greater than 80% as assessed by trypan blue and fluorescein diacetate exclusion. The possibility that immune reactions mediated by the surface-reactive antibody with readily accessible cell surface autoantigens in vivo may contribute to the loss of oligodendrocytes and demyelination in MS is raised.

Adolescent↗
PubMed1983

Transfer of murine experimental autoimmune encephalomyelitis and cell-mediated immunity to myelin protein is effected by Lyt-1 cells.

Cellular transfer of experimental autoimmune encephalomyelitis (EAE) was effected in mice with lymph node cells (LNC) from appropriately immunized donors. Pretreatment of LNC with anti-Lyt-1 and Lyt-2,3 antibodies indicated that the transfer of both EAE and a cell-mediated immune response in vitro to MBP was dependent on a subpopulation of T lymphocytes expressing the phenotype associated with the helper and cell-mediated delayed hypersensitivity functions, Lyt-1+, 2-.

Animals↗
PubMed1983

Inhibition of long-term memory formation in the chicken by anti chick Thy-1 antibody.

Anti-chick Thy-1 antibodies administered close to a single trial passive avoidance learning task in day-old chicks resulted in inhibition of long-term memory formation. The retention time course was comparable to that obtained with the protein synthesis inhibitor anisomycin. The amnestic effect of the anti-chick Thy-1 antibody appears to be mediated solely by immunoglobulin G, and is species specific since anti-rat Thy-1 antibodies did not produce amnesia. The results are consistent with a three stage model of memory formation, suggest a role for glycoproteins in long term memory formation, and emphasise the potential of neuroimmunological tools for investigating the neurological bases of memory formation.

Animals↗
PubMed1983

Do antibodies to myelin basic protein isolated from multiple sclerosis cross-react with measles and other common virus antigens?

Immunological activity to various antigens, including brain components, measles and other viruses, has been associated with IgG in multiple sclerosis (MS). One possible explanation for the presence of anti-viral antibodies and antibody to myelin basic protein (MBP) in MS patients is that there are antigenic determinants common to certain viruses and MBP. To assess this possibility, IgG from individual brains and sera from patients with MS, subacute sclerosing panencephalitis (SSPE) and controls was isolated by protein A and MBP-Sepharose affinity chromatography. Antibody to MBP was measured with a solid phase radioimmunoassay and antibody to measles and other viruses by immunofluorescence and/or complement fixation. Anti-MBP activity was detected in brain extracts and sera of all MS patients tested. In contrast to the low levels of antibody to MBP in control brains, high levels of anti-MBP antibodies were found in most of the normal sera. There was no correlation between the presence and levels of serum anti-measles antibodies and the anti-MBP activity. None of the anti-MBP antibodies affinity purified from brain and serum of MS patients reacted with any of the viruses tested, including measles. IgG purified from SSPE patients or from a rabbit hyperimmunized with measles antigen had no reactivity to MBP, despite high levels of anti-measles antibody. It is concluded that there is not direct link between the presence of antibody to MBP and antibody to measles and other viruses in MS patients.

Adenoviridae↗