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Biomedical subjects

M Revel

Publications and source records attributed to M Revel.

At least 127 records · Page 7Linked to original sources
PubMed1992

Interleukin-6 protects ductal breast carcinoma cells from MHC-unrestricted cell-mediated cytotoxicity.

Interleukin-6 (IL-6) has various biological activities including growth stimulation and maturation of B cells into antibody-producing cells, growth stimulation of murine hybridoma and plasmacytoma cells, induction of acute phase proteins, activation of T cell functions, triggering differentiation of various hematopoietic cells, and inhibition of growth of the human ductal breast carcinoma cell line T-47. Recently it was found that IL-6 also has the ability to enhance natural killer (NK) cell activity. In the present study the possible role of IL-6 as a regulator of NK cell-mediated cytotoxicity (NK-CMC) was evaluated. It was found that IL-6 reduced the sensitivity of T-47 cells (a ductal breast carcinoma cell line) to NK-CMC. The mechanism of IL-6-induced protection was studied. IL-6 had no effect on the level of conjugate formation between T-47 cells and NK cells. However, IL-6 reduced the number of dead conjugated T-47 cells. IL-6-treated T-47 cells were also found to be as sensitive as the nontreated cells to the lytic effect of NK cytotoxic factor (NKCF). However, IL-6 appeared to reduce the ability of T-47 cells to induce release of NKCF from NK cells following conjugate formation. Therefore, it is suggested that IL-6 protects T-47 cells from natural killing by the same mechanism as interferon.

Breast Neoplasms↗
PubMed1992

Effects of repetitive strains on vertebral end plates in young rats.

A histologic study of vertebral end plates was performed on young rats' tails subjected to intensive passive motion. Seven six-week-old rats had two-hour motion cycles daily, for two months. Histologic changes of proximal caudal vertebrae in the experimental group were compared with those of a control group of seven rats of the same litter which were allowed to grow freely without mechanical stress. The main findings were three striking protrusions of disk tissue into end plates, not observed in the control animals. End plate axial bulges lacking spindle-shaped cells and an increase in chondrocytes in the adjacent articular cartilage were observed. The growth-plate thickness was uneven and was absent in some areas, with disorganization of chondrocyte columns. All of these findings were present to a lesser degree in the control group and appeared to be similar to histologic changes observed in Scheuermann's disease.

Animals↗
PubMed1992

[Lumbo-radicular pain caused by epidural lipomatosis in an obese patient: recovery after hypocaloric diet].

The case reported concerns an obese patient suffering from lumbo-radicular intermittent claudication due to lumbar epidural lipomatosis. Compression was revealed by magnetic resonance imaging which showed the existence of a hypersignal in weighted sequences in T1 situated in the epidural space and narrowing the dural sheath. Three cases of lumbar epidural lipomatosis related to obesity have already been described. Treatment in all three was surgical with the result assessed as good in one case and poor in two. The interest of the present case is demonstration of the cause and effect relationship between epidural lipomatosis and obesity as shown by complete restoration of the epidural space after a calorie-controlled diet, and the possibility of successful treatment by this technique.

Diet, Reducing↗
PubMed1991

IL-6 and IL-6 receptor modulation by IFN-gamma and tumor necrosis factor-alpha in human monocytic cell line (THP-1). Priming effect of IFN-gamma.

The present work is a detailed study of the mechanism of IFN-gamma- and TNF-alpha-triggered IL-6 secretion and IL-6 gene expression in human monocytic THP-1 cells and of the effect of these cytokines on the expression of IL-6 surface receptor and IL-6R gene. Although TNF-alpha was shown to stimulate IL-6 expression in fibroblasts in monocytic THP-1 cells, IFN-gamma is required for TNF to induce IL-6 expression. The results reported here demonstrate that combined treatment of THP-1 cells with IFN-gamma + TNF-alpha induced IL-6 mRNA expression, whereas no significant induction was obtained by either cytokine alone. Nuclear run-on transcription assay showed that the increased level of IL-6 mRNA induced by IFN-gamma + TNF-alpha was associated with induction of gene transcription. Sequential stimulation of THP-1 cells by IFN-gamma and subsequently by TNF-alpha did not allow IL-6 gene induction, suggesting that IFN-gamma and TNF-alpha induced or activated different signaling factors which should act together to trigger IL-6 gene transcription. IFN-gamma pretreatment followed by IFN-gamma + TNF-alpha restimulation led to superinduction of the IL-6 gene expression with a concomitant increase in IL-6-secreted activity. This priming effect of IFN-gamma is dependent on active protein synthesis. Biochemical characterization of IL-6 proteins secreted by THP-1 cells by Western blotting and affinity chromatography allowed identification of a major IL-6 molecular species of 42 kDa and a minor one of 23 kDa. Furthermore, we showed here that IFN-gamma increased the IL-6R mRNA level with a concomitant increase in IL-6-specific binding to surface receptors. On the contrary, treatment with IFN-gamma + TNF-alpha reduced the level of IL-6R mRNA and IL-6 binding to THP-1 cells probably due to a ligand-mediated effect. Taken together, results reported here provide evidence that functional interaction between IFN-gamma and TNF-alpha is involved in the regulation of IL-6 and IL-6R expression in monocytic cells. Control of IL-6 production and IL-6R expression may be one of the important homeostatic properties of IFN-gamma.

Cell Line↗
PubMed1991

[Tendinitis of the knee].

The diagnostic criteria for tendinitis of the knee are: (1) strict localization of the pain in the whole length of the tendon from its body to its end; (2) recrudescence of pain during movements that stretch or rub the tendon, and (3) positive local anaesthesia test if needed. Only this approach makes it possible not to miss a tendinitis of the extensor system in a so-called femoro-patellar syndrome, or to misdiagnose a tendinitis of the sartorius, gracilis and semitendinosus muscles when confronted with an osteoarticular pathology of the medial femoro-tibial compartment.

Humans↗
PubMed1991

Eye-head coupling in humans. II. Phasic components.

A tonic coupling between the horizontal component of eye position and dorsal neck muscle activity has been demonstrated in animals and humans. In addition, a transient saccade related coupling has been found in animals. In order to investigate such a phasic component of the eye-head synergy in humans, we have recorded the activity of isolated motor units in the splenius muscle during large horizontal eye movements in head fixed subjects. Eye movement recording was achieved by conventional binocular electro-oculography and the activity of the right splenius muscle was recorded with Bronks coaxial electrodes inserted manually at the C4-C5 intervertebral level. We found two main types of motor unit discharge patterns in the splenius (SPMU), the first type (type A, 14 SPMUs) shows a phasic modulation of firing rate during saccades with a triphasic profile composed of a pre-saccadic suppression, a per-saccadic burst and a post saccadic tonic discharge proportional to eye position. The second type (type B, 6 SPMUs) exhibits little, if any, modulation of firing rate with either fixation or saccades. These results suggest that eye-head coupling is present not only during the fixation period but also during saccades and that a phasic activity or suppression related to saccadic eye velocity is present in dorsal neck muscle EMG.

Adult↗
PubMed1991

Lymphokine-activated killer (LAK) cells: interferon-gamma synergizes with interleukin-2 to induce LAK cytotoxicity in homogeneous leukemic preparations.

Lymphokine-activated killer (LAK) cells are generated by the incubation of lymphocytes with high levels of interleukin-2 (IL-2). We report here that interferon-gamma (IFN-gamma) acts synergistically with low levels of IL-2 to promote LAK differentiation in peripheral blood lymphocytes as well as in homogeneous T acute lymphocytic leukemic cells exhibiting LAK precursor reactivity. No augmentation of LAK response was observed with IFN-alpha-2, IFN-beta-1, and IFN-beta-2/IL-6. The synergism between IL-2 and IFN-gamma was expressed in the ability of activated lymphocytes to lyse natural killer resistant cell line targets and surgically removed melanoma cells. The augmented LAK response due to IFN-gamma does not reflect up-regulation of the high-affinity IL-2 receptors consisting both of alpha and beta subunits, since expression of the alpha (Tac) subunit on the responding leukemic cells was not increased by IFN-gamma. The observed IFN-gamma/IL-2 synergism in the induction of monoclonal LAK precursors suggests that a single precursor cell responds to both IFN-gamma and IL-2 and that different mechanisms underlie the basal IL-2-mediated LAK response and its enhancement by IFN-gamma.

Cytotoxicity, Immunologic↗
PubMed1991

Interleukin-6 induces the (2'-5') oligoadenylate synthetase gene in M1 cells through an effect on the interferon-responsive enhancer.

Interleukin-6 (IL-6) activates (2'-5') A synthetase (2'-5' AS) gene expression in differentiating myeloleukemic M1 cells. Antibodies to type I interferon (IFN) inhibit 2'-5' AS induction but not differentiation. Analysis of the mechanism of 2'-5' AS induction shows that it does not result from increased IFN formation, but from a synergism between IL-6 and endogenously secreted IFN. IL-6 can activate expression of a CAT construct fused to the interferon response sequence (IRS) of the 2'-5' AS gene. In extracts of IL-6-treated M1 cells, changes in protein binding to IRS DNA can be demonstrated. One of the effects of IL-6 on M1 cells is, therefore, to induce DNA binding factors, some of which act on the same enhancer sequence as IFNs, resulting in a synergistic gene activation. M1 variants resistant to differentiation by IL-6 have lost the ability to induce the 2'-5' AS gene.

2',5'-Oligoadenylate Synthetase↗
PubMed1991

Monoclonal antibodies to the soluble human IL-6 receptor: affinity purification, ELISA, and inhibition of ligand binding.

Soluble IL-6 receptor (IL-6-R) purified to homogeneity from normal human urine was used for immunization of mice and rabbits. Spleen cells derived from a mouse showing a high binding titer to IL-6-R in an inverted solid phase radioimmunoassay (IsRIA) and in a Western blotting analysis were fused to mouse myeloma cells. The hybridomas were screened by the IsRIA, and 30 positive clones were isolated and characterized. They were suitable for affinity purification of the IL-6-R and for its detection by Western blot analysis, by ELISA and by sandwich type sRIA. Most of them inhibited the binding of labeled IL-6-R to IL-6 in a solid phase RIA.

Animals↗
PubMed1991

Terminal differentiation of myeloleukemic M1 cells induced by IL-6: role of endogenous interferon.

During terminal differentiation of myeloleukemic M1 cells triggered by IL-6, an induction of IFN-activated genes, such as IRF-1, class I MHC, and (2'-5')-A synthetase, is observed. Antibodies to murine type I IFN, inhibit most (2'-5')-A synthetase induction but do not inhibit IL-6-induced growth-arrest and differentiation. IL-6 induction of (2'-5')-A synthetase subforms, however, differs from that of IFN. IL-6 in fact induces a cell surface form of (2'-5')-A synthetase that is not induced by IFN.

2',5'-Oligoadenylate Synthetase↗
PubMed1991

Cervicocephalic kinesthetic sensibility in patients with cervical pain.

Head orientation in space makes use of multiple sensory afferents, among which the cervical proprioceptive cues could play a predominant role. To quantify the alteration of neck proprioception in patients with cervical pathology, we proposed a test for the clinical evaluation of the ability to relocate the head on the trunk after an active head movement, for 30 healthy subjects and 30 patients with cervical pain. The data demonstrated that this ability was significantly poorer in the patient group, indicating an alteration in neck proprioception. This test permits a discriminant classification of healthy and sick subjects, justifies proprioceptive rehabilitation programs, and allows a quantitative evaluation of their results.

Adult↗
PubMed1990

Purification of soluble cytokine receptors from normal human urine by ligand-affinity and immunoaffinity chromatography.

Affinity chromatography of crude human urinary proteins on either human recombinant interleukin-6 (rIL-6) or human recombinant interferon-gamma (rIFN-gamma) or anti IFN-gamma receptor (IFN-gamma-R) monoclonal antibodies (McAb) yielded the two respective soluble receptors in significant amounts. A single sequence of 30 amino acid residues was obtained by N-terminal microsequencing of the protein peak purified in tandem by affinity chromatography on an IL-6 column and reversed-phase high-performance liquid chromatography. This sequence was identical with the predicted N-terminal sequence of IL-6-R as previously reported. The purified IL-6-R retained its biological activity. It was used for the preparation of specific anti IL-6-R monoclonal antibodies. Analysis of the eluted proteins from both IFN-gamma and anti IFN-gamma-R columns by inhibition of solid-phase radioimmunoassay, enzyme-linked immunosorbent assay, sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blotting proved the existence of soluble IFN-gamma-R in normal urine. This finding together with the already known presence of soluble TNF receptors and a soluble IL-2 receptor found both in plasma and in urine indicates that release of soluble cytokine receptors into body fluids is a general phenomenon which occurs under normal physiological conditions.

Chromatography, Affinity↗
PubMed1990

[Evaluation of thiocolchicoside as monotherapy in low back pain. Results of a randomized study versus placebo].

Thiocolchicoside is a muscle relaxant which, due to its mainly spinal GABA-agonist activity, is used by the oral and intramuscular routes in the ambulatory treatment of painful contracture of the skeletal muscles. The effectiveness and acceptability of this drug in the treatment of acute low-back pain were evaluated in a multicentre, randomized, double-blind, drug versus placebo trial involving 98 patients. The effectiveness of thiocolchicoside was assessed on the following criteria: patients' overall opinion, pain intensity, number of analgesic tablets taken, vertebral rigidity and ability to resume ordinary daily tasks. The results obtained showed that thiocolchicoside significantly improves the principal criterion by the second day of treatment and the other criteria within 5 days.

Adult↗
PubMed1990

Method of quantitative anatomical study of the dorsal neck muscles. Preliminary study.

Biomechanical models of the cervical spine require knowledge of the position, size and orientation of the individual muscles that act on the cervical spine. We have developed a technique to stereometrically measure anatomical specimens. The apparatus is composed of three graduated metallic rods, which slide along a fixed support. This method is accurate to map the anatomy of individual muscles and provides quantitative data on their lines of action. Results are obtained from one specimen. The computer processing of the collected data allows formulation of a three-dimensional model of the neck muscles in man.

Biomechanical Phenomena↗
PubMed1990

Identification of interleukin-6 as an autocrine growth factor for Epstein-Barr virus-immortalized B cells.

Autocrine growth factors are believed to be important for maintenance of an immortalized state by Epstein-Barr virus (EBV), because cell-free supernatants of EBV-immortalized cell lines promote the proliferation of autologous cells and permit their growth at low cell density. In this study, we provide evidence for the existence of two autocrine growth factor activities produced by EBV-immortalized lines distinguished by size and biological activities. Much of the autocrine growth factor activity in lymphoblastoid cell line supernatants resided in a low-molecular-weight (less than 5,000) fraction. However, up to 20 to 30% of the autocrine growth factor activity resided in the high-molecular-weight (greater than 5,000) fraction. While the nature of the low-molecular-weight growth factor activity remains undefined, the high-molecular-weight growth factor activity was identified as interleukin-6 (IL-6). Culture supernatants from six EBV-induced lymphoblastoid cell lines tested contained IL-6 activity, because they promoted proliferation in the IL-6-dependent hybridoma cell line B9. In addition, a rabbit antibody to human IL-6 neutralized the capacity of the high-molecular-weight (greater than 5,000) fraction of a lymphoblastoid cell line supernatant to promote growth both in autologous EBV-immortalized cells and in B9 cells. Similarly, this high-molecular-weight autocrine growth factor activity was neutralized by a monoclonal antibody to human IL-6. Furthermore, characteristic bands, attributable to IL-6, were visualized in supernatants of each of four EBV-induced lymphoblastoid cell lines after immunoprecipitation with a rabbit antiserum to human IL-6. Thus, in addition to its previously reported properties, IL-6 is an autocrine growth factor for EBV-immortalized B cells cultured under serum-free conditions.

B-Lymphocytes↗
PubMed1989

Host defense against infections and inflammations: role of the multifunctional IL-6/IFN-beta 2 cytokine.

IL-6/IFN-beta 2 appears to be one of the important mediators of the response to viral and bacterial infections and to shock. The biological effects now associated with IL-6/IFN-beta 2 include: stimulation of immunoglobulin secretion by mature B lymphocytes (BSF-2 activity), growth stimulation of plasmacytomas and hybridomas (HGF activity), activation of T cells, stimulation of hepatic acute phase protein synthesis (HSF activity), stimulation of hematopoiesis, cell differentiation (DIF activity), inhibition of tumor cell growth (AP activity) and other IFN-like effects. As a typical cytokine, IL-6/IFN-beta 2 is secreted by many cell types and acts in various combinations with other interleukins and interferons.

Cell Differentiation↗
PubMed1989

Entamoeba histolytica ribosomal RNA genes are carried on palindromic circular DNA molecules.

Highly abundant DNA fragments obtained after restriction enzyme digests of nuclear DNA of Entamoeba histolytica strain HM-1:IMSS have been cloned and characterized. Northern blot hybridization to E. histolytica rRNA and sequence analysis identified the abundant DNAs as ribosomal DNA containing species. Several overlapping clones containing these abundant DNAs were isolated from 4 different genomic libraries of E. histolytica. Alignment of the restriction maps was consistent with a circular molecule, about 24.6 kilobase pairs (kb) in size. Nuclease BA131 digestion provided additional evidence for the circular nature of this DNA. The ribosomal DNA molecule contains two large inverted repeat-regions, each at least 5.2 kb in length. Sequence analysis of clone R715 revealed homology to the large rRNA units of various eukaryotic organisms. This clone was located in both inverted repeats, suggesting two rRNA cistrons per molecule. The inverted repeats are flanked by stretches of DNA which contain tandemly reiterated sequences. Southern blot analysis of E. histolytica nuclear DNA revealed the presence of two populations of molecules. These molecules have identical arrangements of restriction sites, but differ in size (0.7 kb) in a fragment containing tandemly reiterated sequences. Analysis of E. histolytica nuclear DNA by electron microscopy also revealed circular molecules. These molecules are about 26.6 kb +/- 0.5 kb in size and contain structural features predicted by the restriction map of the extrachromosomal ribosomal DNA of E. histolytica.

Animals↗