Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:009512 (tumor necrosis factor)
 58,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The non-obese diabetic (NOD) mouse is an animal model of human insulin dependent diabetes mellitus (IDDM). In this strain, the serum concentration of tumor necrosis factor-alpha (TNF alpha) after OK432 (a streptococcal preparation) stimulation is much lower than in any other non-diabetic control strain. Female NOD mice which have a higher incidence of diabetes have significantly lower TNF alpha level (6.5 +/- 4 U/ml, mean +/- SEM) than do male NOD mice (21 +/- 5 U/ml) (P < 0.02) which have lower incidence of diabetes. On the basis of these results, we designed a prospective study to evaluate the relationship between the serum TNF alpha concentration and the incidence of diabetes in individual male NOD mice. Mice were studied until 30 weeks of age. During this period four of eight mice with a low TNF alpha level (TNF alpha < or = 1.1 U/ml) became diabetic, whereas none of eighteen mice with a high TNF alpha level (TNF alpha > 1.1 U/ml) developed overt diabetes. These results indicate that by measuring of endogeneous TNF alpha level after stimulation by OK432, one could predict IDDM in male NOD mice.
Diabetes Res 1992 Feb
PMID:Prediction of insulin dependent diabetes mellitus in non-obese diabetic mice by the endogeneous tumor necrosis factor-alpha level. 128 40

Cytokines play a crucial role in the inflammatory and immune responses. The activity of cytokines is counterbalanced by specific inhibitors with some functioning as receptor antagonists. Inhibitors to interleukin 1 and tumor necrosis factor may have therapeutic potential in conditions such as inflammatory arthritis, diabetes mellitus, disseminated intravascular coagulopathy and septic shock. The ability to modulate host defenses with cytokines and cytokine antagonists may also have applications in the fields of transplantation, oncohematology and immunodeficiency.
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PMID:Immunomodulating functions of tumor necrosis factor and interleukin 1 inhibitors. 131 88

Autoimmune diseases have been studied from the perspective of an abnormal immune response in genetically vulnerable hosts. Although the immune response is responsible for the initiation of autoimmune diseases, the effectors of the disease process likely involves cytokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF). These polypeptides induce a wide variety of inflammatory events which contribute to the destruction of tissue and tissue remodeling in several autoimmune diseases. Blocking IL-1 with its naturally occurring receptor antagonist, the IL-1 receptor antagonist reduces the severity of disease in animal models of inflammation and autoimmune processes. Clinical studies with the IL-1 receptor antagonist will define the role for this cytokine in the pathogenesis of autoimmune diseases such as arthritis, inflammatory bowel disease, type I diabetes and vasculitis.
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PMID:Interleukin-1 and tumor necrosis factor: effector cytokines in autoimmune diseases. 132 Sep 50

It has been proposed that certain cytokines secreted by islet-infiltrating leukocytes may be involved in the pathogenesis of insulin-dependent diabetes mellitus by participation in beta-cell destruction. In the present study, the impact of various cytokines on replication and long-term insulin secretion by pancreatic beta-cells was investigated. To this end, fetal rat pancreatic islets containing a high fraction of beta-cells were exposed in culture for 1-3 days to interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interferon-alpha (IFN-alpha), and interleukin-6 (IL-6) at different concentrations. It was found that IL-1 beta markedly decreased beta-cell DNA synthesis during the first day of exposure, an effect that vanished after 2 days and was turned into a potent and dose-dependent stimulation by 3 days of exposure. At this latter time point, IL-1 beta also amplified the mitogenicity of growth hormone (GH) and 16.7 mM glucose. In contrast, basal as well as glucose- and GH-stimulated insulin secretion was consistently suppressed by IL-1 beta from days 1-3. IL-1 beta also lowered the islet adenosine 3',5'-cyclic monophosphate (cAMP) content at all time points studied. However, addition of the stimulatory cAMP analogue Sp-diastereomer of adenosine 3',5'-cyclic monophosphothioate or pertussis toxin, which themselves enhanced DNA synthesis and insulin secretion, failed to prevent the inhibitory actions of IL-1 beta on these parameters, making it unlikely that a decrease in cAMP is an important event in transduction of the inhibitory effects of the cytokine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Differential effects of cytokines on long-term mitogenic and secretory responses of fetal rat pancreatic beta-cells. 132 36

The blood monocytes adhere to endothelial cells unstimulated and after stimulation by interleukin-1, tumor necrosis factor or other mediators. This process is mediated through specific molecules on both endothelial cells and monocytes. Using specific monoclonal antibodies and molecular cloning several families of molecules involved in leukocyte endothelial cell interaction have been defined. Leukocyte adhesion molecules include the three beta 2 integrins (CD11/CD18 molecules), VLA-4 and the L-Selectin. E-Selectin (ELAM-1), P-Selectin (GMP-140) and receptors of the immunoglobulin superfamily (ICAM-1, ICAM-2 and VCAM-1) are expressed on endothelial cells in basal conditions and after activation. It has been shown that these adhesive molecules are involved in blood monocyte adhesion to endothelial cells. Monocytes from patients with diabetes mellitus had an increased adhesion to endothelial cells in culture. As estimated by flow cytometry CD11b/CD18 expression on diabetic monocytes was increased. Pentoxifylline reduced CD11b/CD18 expression on normal and diabetic monocytes. This effect was associated to a decrease in monocyte adhesion to endothelial cells.
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PMID:Molecular mechanism of blood monocyte adhesion to vascular endothelial cells. 134 May 30

We determined the serum concentrations of tumor necrosis factor (TNF) in 15 nondiabetic healthy subjects and in 36 insulin-dependent (type I) diabetic outpatients. The mean (+/- SD) annual fasting plasma glucose, urine glucose and HbA1 levels of the diabetic group were 179 +/- 71 mg/dl, 13.0 +/- 13.2 g/day and 12.3 +/- 1.3%, respectively. The mean serum TNF concentration measured by immunoradiometric assay of the diabetic group (8.6 +/- 1.9 pg/ml) was significantly higher than healthy controls (6.9 +/- 0.9 pg/ml). Within the diabetic group, there was no correlation between serum TNF levels and either duration of diabetes or indices of metabolic control. However, serum TNF levels progressively increased from the well to the poorly controlled diabetic groups: 8.1 +/- 1.5 (G), 8.2 +/- 1.4 (F) and 9.4 +/- 2.4 (P) pg/ml, respectively, which parallel levels of HbA1 (%): 8.4 +/- 2.4, 11.7 +/- 1.8 and 14.6 +/- 1.2, respectively. Serum TNF levels of the diabetic patients with chronic complications (N = 7, 9.5 +/- 2.3 pg/ml) and without complications (N = 29, 8.4 +/- 1.7 pg/ml) were statistically higher than control subjects. The progressive increase of the serum TNF levels from the well to the poorly controlled diabetic groups suggests a relationship between levels of this cytokine and protein glycosylation.
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PMID:Serum levels of tumor necrosis factor in insulin-dependent diabetic patients. 134 19

The 2.2 A resolution crystal structure of recombinant human manganese superoxide dismutase, a homotetrameric enzyme that protects mitochondria against oxygen-mediated free radical damage, has been determined. Within each subunit, both the N-terminal helical hairpin and C-terminal alpha/beta domains contribute ligands to the catalytic manganese site. Two identical 4-helix bundles, symmetrically assembled from the N-terminal helical hairpins, form novel tetrameric interfaces that stabilize the active sites. Structurally altered polymorphic variants with reduced activity, such as tetrameric interface mutant Ile-58 to Thr, may produce not only an early selective advantage, through enhanced cytotoxicity of tumor necrosis factor for virus-infected cells, but also detrimental effects from increased mitochondrial oxidative damage, contributing to degenerative conditions, including diabetes, aging, and Parkinson's and Alzheimer's diseases.
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PMID:The structure of human mitochondrial manganese superoxide dismutase reveals a novel tetrameric interface of two 4-helix bundles. 139 26

The Bio-Breeding (BB) rat develops spontaneous insulin-dependent diabetes mellitus (IDDM) and provides a useful animal model to study this human autoimmune disease. Treatment of BB rats with tumor necrosis factor (TNF) has been reported to prevent the development of IDDM. This suggests that deficient TNF production may be involved in the immunopathogenesis of autoimmune diabetes. In this study, we evaluated TNF production in diabetes-resistant (DR) BB rats, diabetes-prone (DP) BB rats, and DP BB rats protected from diabetes by the immunoadjuvant, complete Freund's adjuvant (CFA). TNF production in short-term cultures of peritoneal macrophages from DP rats was significantly less than that from control DR rats, both in the basal state and after stimulation with either interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS) in vivo and in vitro. In contrast, TNF production by macrophages from CFA-injected DP rats (basal and IFN-gamma or LPS-stimulated) was equal to or greater than that by macrophages from DP rats and similar to TNF production by macrophages from CFA-injected DR rats. These results suggest that development of autoimmune diabetes in BB rats may be causally related to deficient macrophage production of TNF, and that upregulation of TNF production may protect against diabetes development.
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PMID:Tumor necrosis factor production is deficient in diabetes-prone BB rats and can be corrected by complete Freund's adjuvant: a possible immunoregulatory role of tumor necrosis factor in the prevention of diabetes. 139 29

Mice bearing a tumor necrosis factor (TNF) alpha transgene controlled by an insulin promoter developed an increasingly severe lymphocytic insulitis, apparently resulting from the induction of endothelial changes with features similar to those observed in other places of intense lymphocytic traffic. This was accompanied by dissociation of the endocrine tissue (without marked decrease in its total mass), islet fibrosis, and the development of intraislet ductules containing, by places, beta cells in their walls, suggesting a regenerative capacity. Islet disorganization and fibrosis did not result from lymphocytic infiltration, since they were also observed in SCID mice bearing the transgene. Diabetes never developed, even though a number of potentially inducing conditions were used, including the prolonged perfusion of interferon gamma and the permanent expression of a nontolerogenic viral protein on beta cells (obtained by using mice bearing two transgenes). It is concluded that (a) a slow process of TNF release in pancreatic islets induces insulitis, and may be instrumental in the insulitis resulting from local cell-mediated immune reactions, but (b) that insulitis per se is not diabetogenic, lymphocyte stimulation by cells other than beta cells being necessary to trigger extensive beta cell damage. This provides an explanation for the discrepancy between the occurrence of insulitis and that of clinical disease in autoimmune diabetes.
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PMID:Expression of a tumor necrosis factor alpha transgene in murine pancreatic beta cells results in severe and permanent insulitis without evolution towards diabetes. 146 Apr 28

It is now generally accepted that many cytokines are involved in the pathogenesis of autoimmune disease, either directly by causing tissue destruction or indirectly through the activation of autoreactive and inflammatory cells. Thus, cytokines, such as tumor necrosis factor-alpha, are implicated in the pathogenesis of rheumatoid arthritis based on in vitro studies on synovial tissue from patients with rheumatoid arthritis, which suggest that the effects of tumor necrosis factor-alpha are amplified by its potential to induce other pro-inflammatory cytokines, such as interleukin-1 and granulocyte-macrophage colony-stimulating factor. Transgenic mouse technology has shown that mice expressing the human tumor necrosis factor-alpha gene develop a polyarthritis. Interleukin-2 has also been identified by transgenic technology as a cytokine involved in the pathogenesis of insulin-dependent diabetes mellitus through the activation and stimulation of growth of autoreactive T cells.
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PMID:Cytokines in autoimmunity. 146 99


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