Biomedical subjects

M Feldmann

Publications and source records attributed to M Feldmann.

At least 91 records · Page 5Linked to original sources

PubMed1991

Localization of tumor necrosis factor alpha in synovial tissues and at the cartilage-pannus junction in patients with rheumatoid arthritis.

Using immunoaffinity-purified polyclonal anti-human recombinant tumor necrosis factor alpha (TNF alpha) F(ab')2 fragments and immunohistochemical techniques, the cells that make TNF alpha were localized in the inflamed synovial tissue of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Anti-TNF alpha antibody-stained cells were demonstrated in 9 of 11 RA and 2 of 4 OA but none of 5 normal synovial membranes examined. In RA, 26-64% of the lining layer cells were positive for TNF alpha. In the interaggregate area, 10-30% of the cells contained TNF alpha, often in a perivascular distribution, and up to 19% of the cells in lymphoid aggregates stained for TNF alpha. Some endothelial cells also stained with these antibodies. In OA tissues, the TNF alpha-containing cells were found predominantly in the deeper layer. Cells containing TNF alpha were also found at the cartilage-pannus junction in all 4 RA specimens examined. Double immunofluorescence analysis demonstrated that most TNF alpha-secreting cells in the RA synovial membrane expressed the monocyte/macrophage marker antigens CD11b and CD14, and a few expressed the T cell marker CD3. Our findings provide histologic evidence that TNF alpha is locally produced in the lining and deeper layers of the synovium by cells of the monocyte/macrophage lineage, supporting its role in inflammation. Further, our findings demonstrate that TNF alpha is produced by cells at the cartilage-pannus junction, which could affect chondrocyte metabolism, leading to the cartilage degradation in RA.

Antibodies↗

PubMed1991

Interleukin 4 induces interleukin 6 production by endothelial cells: synergy with interferon-gamma.

Interleukin (IL)4 induces IL6 production by human umbilical vein endothelial cells (HUVEC) in a dose-dependent manner, as shown by bioassay and immunoprecipitation. Interferon (IFN)-gamma, which antagonizes IL4 effects on leukocytes, synergized with IL4 in the induction of IL6 production by HUVEC. Contamination with endotoxin was excluded by heat-inactivated IL4, preincubating with anti-IL4 polyclonal antibody and the use of polymyxin B. The presence of IL4 receptors on HUVEC was shown by affinity cross-linking with 125I-IL4, revealing a 110-kDa binding protein. However, compared with the amount seen on T cells the 60-70-kDa cross-linked doublet was present at much lower levels. Additional lower molecular weight cross-linked proteins were isolated only with HUVEC, but the origin of these is unclear. IL6 is a pluripotent cytokine produced by many cells which promotes the differentiation and growth of lymphocytes and the production of acute phase protein by hepatocytes, and is important in the regulation of immunity at the systemic and local levels. Since IL4 and IFN-gamma are produced by T cells, which are frequently associated with vascular endothelium during chronic inflammation, IL4 is likely to be an important cytokine in the regulation of IL6 and perhaps other cytokine production by endothelium in vivo.

Drug Synergism↗

PubMed1991

Induction of the interleukin 1 receptor antagonist protein by transforming growth factor-beta.

Transforming growth factor-beta 1 (TGF-beta 1) mediates many immunosuppressive effects on immune cells and can inhibit the production of tumor necrosis factor and interleukin 1 (IL 1). However, TGF-beta 1 can stimulate the production of IL 6 and platelet-derived growth factor, indicating that TGF-beta 1 initiates complex effects on the production of cytokines. In this report we show that treatment of peripheral blood monocytes with TGF-beta 1 leads to the induction of a recently described IL 1 receptor antagonist protein (IRAP). The effect of TGF-beta 1 was both dose and time dependent. TGF-beta 1 induced de novo synthesis of IRAP, as Northern blotting experiments indicated a rapid and transient induction of the mRNA encoding IRAP. The induction of IRAP suggests a potential mechanism by which some of the inhibitory effects of TGF-beta 1 are mediated.

Cells, Cultured↗

PubMed1991

Cloning, expression and cross-linking analysis of the murine p55 tumor necrosis factor receptor.

Tumor necrosis factor (TNF) mediates its pleiotropic effects via high-affinity cell surface receptors. In man, molecular cloning has identified two distinct, independent TNF receptors (TNFR) of 55 and 75 kDa. It is unclear, however, whether the multiple effects of TNF are suggested between the receptor types. In the mouse, previous studies had shown functional heterogeneity of TNFR, since the WEHI 164 fibroblast line is sensitive to the cytotoxic effects of both murine and human TNF, whereas the murine T cell line, CT6, proliferates in response to murine but not human TNF. In this study, the cloning of a cDNA encoding the murine homologue of the p55 TNFR is reported. This receptor binds murine and human TNF with equal affinity and is expressed on WEHI 164 and a number of other cell lines, but only low levels of mRNA and no protein is detectable on CT6 cells. CT6 cells, however, express a second TNFR of approximately 75 kDa, identified by cross-linking analysis, which is also found on WEHI 164 cells, and binds only murine TNF. These studies establish that there are also two TNFR in the mouse, and suggests that there may be segregation of the cytotoxic and proliferative responses between different receptors, at least in these cell lines.

Amino Acid Sequence↗

PubMed1991

Expression of granulocyte-macrophage colony-stimulating factor in rheumatoid arthritis: regulation by tumor necrosis factor-alpha.

Granulocyte-macrophage colony-stimulating factor (GM-CSF), in addition to being a growth factor for granulocytes and macrophages, is an activator of cells of the monocyte/macrophage lineage and induces HLA class II expression and cytokine synthesis in these target cells. Macrophage activation and class II expression are prominent features in rheumatoid arthritis (RA) joints, but the mechanism of their stimulation is not understood, since interferon-gamma, the major stimulus of class II expression, is not usually detectable at the protein level in synovial cell culture supernatants. We have, therefore, studied GM-CSF expression in cultures of cells derived from joints affected by RA and osteoarthritis (OA), and show that GM-CSF is produced spontaneously both by RA synovial cells and to a lesser extent by OA synovial cells in the absence of extrinsic stimuli. GM-CSF production continues for the 5-day duration of the culture period. Using neutralizing antibodies to tumor necrosis factor (TNF)-alpha we demonstrated that GM-CSF production in RA synovial cell cultures is dependent on the continued presence of active TNF-alpha. This result supports our concept that continued activation of the cytokine network is a marked feature of RA, and that TNF-alpha plays a pivotal role in this network, by regulating the production of other pro-inflammatory cytokines, such as interleukin 1, as demonstrated previously, and GM-CSF.

Arthritis, Rheumatoid↗

PubMed1991

Interleukin-6 localisation in the synovial membrane in rheumatoid arthritis.

Polyclonal antibodies were raised in rabbits against Interleukin-6 (IL-6) by immunisation with a synthetic peptide of identical sequence to the amino terminal 12 amino acids of human IL-6. These antibodies reacted with recombinant IL-6 by ELISA and stained the cytoplasm of the IL-6 secreting bladder tumour cell line T24. Staining was abolished by prior incubation of the antibody with the IL-6 peptide. F(ab')2 fragments made by pepsin digestion of the IgG were immunopurified, labelled with biotin and retained activity in the biochemical and histological assays. Sections of synovial membrane from patients with rheumatoid arthritis (RA) were stained with these antibodies, using an immunoperoxidase technique, and cells containing IL-6 were domonstrated in the thickened synovial lining layer and also in a perivascular distribution in the deeper synovium. In osteoarthritis there were fewer cells in the lining layer and hence localisation appeared similar in both the interstitial area and lining layer. Double-staining techniques with mouse monoclonal antibodies against cell subset markers in five RA synovial membranes showed that up to 13% of T-cells and 19% of antibody-producing cells stained for IL-6. However, up to 70% of the macrophages contained IL-6 and these were found in close proximity to Ig-producing plasma cells. This study showed that macrophages were the major cells of the immune system in which IL-6 could be localised in RA, and suggests a role for locally produced IL-6 in the stimulation of rheumatoid factor production.

Amino Acids↗

PubMed1991

Unusual encephaloclastic lesions with paraventricular calcification in congenital rubella.

We report an unusual case of congenital rubella. The infant was suffering from a serious encephalopathy, and both prenatal echography and neonatal CT scan showed passive ventriculomegaly with a calcified periventricular border. Usually, such lesions are strongly suggestive of cytomegalovirus (CMV) infection and have never previously been reported in congenital rubella. Classic cerebral lesions in rubella are related to a prominent obstructive vasculopathy. Conversely, encephaloclastic lesions in CMV infection are likely related to a necrosis of brain parenchyma following upon an initial ventriculitis, and perhaps also to a disturbance of neuronal proliferation. Recently, Carey described a neonate with proven congenital rubella and cranial ultrasound findings typical of ventriculitis. However, in spite of the close similarity between our patient's lesions and the typical CMV lesions, we think it's impossible to assert similar pathogenic mechanisms. Actually, it's quite conceivable that only a severe or extensive vasculopathy can lead to brain atrophy with periventricular calcification in congenital rubella.

Brain Diseases↗

PubMed1991

Production of interleukin-1 and interleukin-6 by human keratinocytes and squamous cell carcinoma cell lines.

Cultured human keratinocytes and squamous cell carcinoma (SCC) cell lines were analyzed for the presence of ribonucleic acid (RNA) transcripts for the cytokines interleukin-1 and interleukin-6 and for these proteins. This study demonstrates that both cytokines are synthesized and secreted by both normal keratinocytes and SCC lines. The rate of secretion of these cytokines can be augmented in response to a variety of stimuli including tumor necrosis factor-alpha, granulocyte-macrophage colony stimulating factor, transforming growth factor-beta and the combination of lipopolysaccharide and phorbol myristate acetate. Interleukin-1 and interleukin-6 have been reported to influence the proliferation of cultured human fibroblasts. However, these cytokines had no significant effect on the proliferation of human keratinocytes or the SCC lines tested. Although it seems unlikely that interleukin-1 or interleukin-6 could directly influence keratinocyte proliferation in vivo, the capacity of these cells to synthesize and release these cytokines supports earlier observations that keratinocytes may play an important role in augmenting an immune or inflammatory response.

Carcinoma, Squamous Cell↗

PubMed1991

Transforming growth factor-beta 1 in rheumatoid synovial membrane and cartilage/pannus junction.

Transforming growth factor (TGF)-beta has been shown to promote tissue repair and have immunosuppressive actions, and has been proposed to have a role in rheumatoid arthritis (RA). Using immunohistochemical techniques with rabbit F(ab')2 antibodies raised against recombinant human TGF-beta 1, we have detected TGF-beta 1 in the synovial tissue and cartilage/pannus junction (CPJ) from 18/18 patients with RA. TGF-beta 1 was found predominantly in the thickened synovial lining layer in RA, but also detected in a perivascular pattern in the synovial interstitium as well as in occasional cells in the lymphoid aggregates. At the CPJ it was found both in cells at the distinct junction as well as in the transitional region of the diffuse fibroblastic zone. The cells staining for TGF-beta 1 were identified by double immunofluorescence staining as being from the monocyte/macrophage series as well as the type B synovial lining cells. TGF-beta 1 was also detected in the synovial membrane sections from 4/4 patients with systemic lupus erythematosus/mixed connective tissue disease and 5/8 patients with osteoarthritis, in a similar distribution to that seen in RA, and in the lining layer of 1/7 normal synovial membranes. These results add to histological evidence confirming that TGF-beta 1 is present in RA synovial cells and those from other arthritides. The distributions of TGF-beta 1 in RA synovial membrane reflects its known actions, as it can be detected at the CPJ, where it could induce repair, and close to activated cells upon which it may exert an immunosuppressive action.

Antibodies, Monoclonal↗

PubMed1991

Detection of interleukin-6 and interleukin-1 production in human thyroid epithelial cells by non-radioactive in situ hybridization and immunohistochemical methods.

Human endocrine thyroid epithelial cells have been described to produce cytokines in vitro. In order to determine whether they do so in vivo during thyroiditis, parallel studies on mRNA expression with a non-radioactive in situ hybridization technique and immunohistochemical detection for the protein were performed on frozen sections of thyroid samples from autoimmune thyroiditis (Graves' disease and Hashimoto's thyroiditis), non-toxic goitre and normal thyroid tissue. cDNA probes were sulphonated and their hybridization with mRNA was detected with a sulphonyl-specific monoclonal antibody. This signal was amplified and visualized with the alkaline phosphatase-anti-alkaline phosphatase (APAAP) system. The protein products were detected with immuno-purified rabbit F(ab')2 antibody fragments recognizing recombinant human cytokines, visualized by the immunoperoxidase technique. Each sample was studied at the two levels. Both interleukin-6 mRNA and protein were found in the endocrine cells. There was no obvious difference between autoimmune thyroiditis and non-toxic goitre. However, normal thyroid epithelial cells produced less interleukin-6. Interleukin-1 alpha mRNA and its protein were found in epithelial cells from Hashimoto's thyroiditis samples, but not in the others, except one Graves' disease sample, in which only mRNA was detected. Interleukin-1 beta was not detected in these cells, its mRNA was only found in one of the Graves' disease samples. These cytokines were also detected in some infiltrating cells.

Epithelium↗

PubMed1991

Selective activation of T cells in newly diagnosed insulin-dependent diabetic patients: evidence for heterogeneity of T cell receptor usage.

Cell surface phenotyping of 58 newly diagnosed diabetic children and 25 controls confirmed the presence of activated T cells, expressing HLA class II antigens or receptors for interleukin-2 (IL-2R, CD25) in the majority of the patients. Some of these cells putatively include those involved in islet cell destruction, as reported previously. Monoclonal antibodies recognizing three families of the variable regions of the beta chain (V beta) of the T cell receptor were used to determine the percentage of peripheral blood cells expressing those specific gene segment products. The number of the activated T cells from each V beta family was compared with that of the resting T cells of the same family in the patients and the controls. In 18 out of 58 (31%) of these patients there was evidence of oligoclonal proliferation of activated T cells as judged by marked increases in cells expressing a V beta family in the IL-2R+ T cell pool, compared with the total T cell pool. However, different V beta families were augmented in individual patients, indicating considerable heterogeneity of T cell activation in different patients. These results are in contrast to murine models of autoimmunity, where virtually monoclonal T cell activation, restricted to a single V beta family has been reported.

Adolescent↗

PubMed1991

Cytokine assays: role in evaluation of the pathogenesis of autoimmunity.

Cytokines are protein mediators involved in inflammation, the immune response, cell growth, repair and fibrosis. All of these processes are ongoing in active autoimmune diseases such as rheumatoid arthritis (RA), and so it would be expected that many cytokines would be actively produced in RA joints or Graves' disease (GD) thyroid glands. The cDNA cloning of cytokines has permitted the generation of pure recombinant molecules, and of newer more sensitive assays, and spurred the rapid development of knowledge in this field. Here we review the molecular strategies devised to study the possible role of cytokines in the pathogenesis of RA and GD, and describe some of the initial results. After 'cataloguing' the relative abundance of various cytokines, we sought to discover which cytokines are of major importance in pathogenesis. For that purpose we used neutralizing anti-cytokine antibodies and found that TNF alpha is one of the major signals regulating the production of IL-1 in the RA but not in the osteoarthritic (OA) joint. In order to further understand the dynamics of the cytokine network, the localization of the cytokine-producing cells by immunostaining and in situ hybridization has also been performed. The latter techniques are particularly valuable for attempting to establish the role of the target cell, such as thyroid epithelium, in the pathogenesis of disease. Cytokines act on cells via binding to high-affinity receptors. The last two years has been the cDNA cloning of many molecules encoding cytokine receptor chains, and it is now possible to begin to evaluate the other half of the cytokine pathway. Taken together, there are now exciting opportunities for the molecular dissection of the cytokine events occurring in auto-immune tissues.

Animals↗

PubMed1991

c-erbB-2 expression in different histological types of invasive breast carcinoma.

Sections of 149 breast carcinomas were examined for the over-expression of c-erbB-2 oncoprotein using the avidin-biotin immunoperoxidase technique and two different specific antibodies. These included the polyclonal antibody 21N and the monoclonal antibody 4D5. The tumours were divided into two main groups. The first included 75 cases of invasive ductal and classic invasive lobular carcinomas. The second group consisted of 74 cases with histological types known to have a good prognosis, including mucinous, alveolar variant of invasive lobular, medullary, tubular, cribriform and papillary carcinomas. Fifteen (20%) tumours of the first group were positive with the two antibodies. Fourteen of these were of the ductal type and one was a mixed invasive ductal and lobular carcinoma. Ten of the pure ductal cases had areas of comedo carcinoma. The intraductal elements in a further tumour were positively stained with 21N antibody only. None of the second group of tumours, which included histological types known to have good prognosis, stained with 4D5, although one mucinous carcinoma was positively stained with 21N. These findings suggest that in invasive breast carcinoma immunostaining for c-erbB-2 is mainly seen in a subgroup of ductal tumours, and that almost all other histological types, especially those associated with good prognosis, lack this expression.

Breast Neoplasms↗

PubMed1991

Cytokine expression in rheumatoid arthritis.

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Animals↗

PubMed1990

Safety aspects of transcranial brain stimulation in man tested by single photon emission-computed tomography.

Single photon emission-computed tomography (SPECT) using 99mTc-labelled hexamethylpropyleneamine oxime (99mTc-HMPAO), a new method to visualize regional cerebral blood flow (rCBF) and epileptogenic foci, was used to study acute and long-term effects of transcranial brain stimulation. Magnetic and electric brain stimulation increase rCBF not more than voluntary muscle activation mimicking the motor effects of transcranial brain stimulation. Focal rCBF increase, typical for epileptogenic foci, or other pathological findings could not be detected even when the subject had received several thousand stimulations in the past. Transcranial brain stimulation does not produce rCBF patterns indicating acute or chronic adverse effects.

Adult↗

PubMed1990

Interleukin 7 is a growth factor for mature human T cells.

We have studied the capacity of interleukin (IL) 7 to support the growth and expansion of human T cell clones of different phenotype and function. All the clones studied (CD4+CD8+, CD4-CD8- Tcell receptor alpha/beta or gamma/delta) responded to IL 7. The proliferative response of all the T cell clones induced by IL 7 was routinely less than to IL2, but comparable to the IL4 response. IL 7 also induced the proliferation of resting, freshly prepared peripheral blood mononuclear cells (PBMC) or Tcell-enriched (E+) cells. The pattern of proliferation observed in the presence of IL 7 was similar, but lower in magnitude, to that induced by IL 2. In both these cells populations the response to lymphokines alone was always less than the response to lymphokines plus insolubilized anti-CD3 monoclonal antibody. In contrast IL4 produced a different pattern of responsiveness, as significant proliferation was observed only on PBMC costimulated with anti-CD3. The possibility that IL 7 mediates its growth stimulation by the IL2 pathway was excluded by the incapacity of anti-IL2 or anti-Tac monoclonal antibody, in concentrations which blocked IL2-dependent proliferation, to inhibit IL 7-dependent growth. We conclude that IL 7 is a major growth factor for human mature T cells, and its activity is not limited to lymphocyte progenitors.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1990

Detection of interleukin 8 biological activity in synovial fluids from patients with rheumatoid arthritis and production of interleukin 8 mRNA by isolated synovial cells.

The presence of neutrophils in the synovial joint of patients with rheumatoid arthritis (RA) is thought to be due to the activity of chemotactic factors released by activated cells in the joint. We have shown in this report, for the first time, the abundance of one such factor, interleukin 8 (IL 8), in the synovial fluid of patients both with RA and other non-RA joint diseases, and the spontaneous production of IL 8 mRNA by RA synovial cells in culture. There was no correlation between the levels of chemotactic activity and IL 8 protein, suggesting that other factors with similar neutrophil chemotactic activity are also present in the synovial fluid exudate. In support of this concept neither the level of chemotactic activity nor IL 8 protein levels correlated with neutrophil or leukocyte infiltration, indicating that the mechanism of migration into the inflammatory environment of the joint is complex. Such migration is likely to be due to a number of chemotactic signals in addition to IL 8, which may either synergize with, or inhibit, the action of IL 8.

Adult↗

PubMed1990

99mTc-hexamethylpropylene amine oxime SPECT and X-ray CT in acute cerebral ischaemia.

Early diagnosis of acute cerebral ischaemia is still unsatisfactory, because X-ray computed tomography (CT) does not reveal the site and extent of hypoperfusion within the first 24 h. Single photon emission computed tomography (SPECT) using 99mTc-hexamethylpropylene amine oxime (HMPAO) may offer earlier information, since the distribution of HMPAO follows the actual cerebral perfusion pattern. We therefore investigated 53 patients suffering from acute cerebral ischaemia (10 with transient ischaemic attacks, 9 with prolonged ischaemic reversible neurological deficits, 34 with completed stroke). SPECT and CT examinations were performed on days 1, 3, and 14. On day 1, SPECT revealed hypoperfused areas in 42 patients, whereas CT showed hypodensities only in 5. The sensitivity of SPECT was higher in cortical compared with subcortical ischaemia. In patients suffering from reversible neurological deficits SPECT normalized in the follow-up, corresponding to clinical improvement. In completed stroke, SPECT demonstrated variable perfusion patterns with hypo-, normo-, and hypoperfused areas on day 3 and especially on day 14. In contrast to CT, HMPAO SPECT leads to early diagnosis of cerebral ischaemia, in particular within the cerebral cortex.

Aged↗