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At least 181 records · Page 10Linked to original sources

Liver X receptor activation decreases the severity of experimental autoimmune encephalomyelitis.

Agonists of liver X receptors (LXR), members of the nuclear hormone receptor superfamily, alter secretion of proinflammatory cytokines, suggesting potential antiinflammatory effects. A synthetic LXR agonist inhibited T-cell proliferation and cytokine release in a dose-dependent manner. Treatment of mice during induction of experimental autoimmune encephalomyelitis reduced clinical symptoms, central nervous system cellular inflammation, and major histocompatibility class II expression on microglia, as well as demyelination. In contrast to in vitro analysis, no reductions in peripheral neuroantigen specific T-cell responses were detected in comparing ligand and vehicle treated mice. These data suggest that LXR agonists play an important protective role in the regulation of T-cell-mediated inflammatory disease of the central nervous system.

Animals↗

IL-6 induces expression of the Fli-1 proto-oncogene via STAT3.

Induction of gene expression by IL-6 has become an area of intense interest due to the role this cytokine plays in mediating aspects of inflammation, cellular differentiation, and proliferation. The ETS family of transcription factors represents a group of positive and negative regulators of transcription, that are differentially expressed in a cell and tissue specific manner. The ETS protein Fli-1 is known to induce differentiation in the erythroblastic leukemia cell line K562 along megakaryocytic developmental pathways. Here we show that IL-6 treatment of K562 induces the expression of Fli-1 via the STAT3 transcription factor. Upregulation of Fli-1 expression can be abrogated by the addition of AG490, a chemical inhibitor of JAK kinases, and by transfecting the cells with a dominant negative STAT3 expression construct.

Binding Sites↗

In vivo nasal challenge with diesel exhaust particles enhances expression of the CC chemokines rantes, MIP-1alpha, and MCP-3 in humans.

Diesel exhaust particles (DEP) enhance allergic inflammation by increasing in vivo IgE and cytokine production in the human upper respiratory mucosa. CC chemokines have been shown to play an important role in inflammation. We examined whether DEP could alter the production of CC chemokines by cells residing in the human nasal mucosa. At both 6 and 24 h following intranasal DEP challenge, the levels of nasal RANTES, MIP-1alpha, and MCP-3 were significantly elevated compared to baseline. In contrast, DEP did not enhance levels of Eotaxin at any time, demonstrating that the action of DEP was not simply a global effect on all CC chemokines. Challenge with saline resulted in no significant change in expression of any chemokine at any time. Challenge with DEP also resulted in an increase in total cell counts in nasal lavage fluids. Increases in lymphocyte, monocyte/macrophage, and neutrophil cells were observed but there was no change in eosinophil cell numbers. In contrast, there was a significant enhancement of ECP protein levels in washes performed 6 to 24 h after DEP challenge. Elevated specific nasal chemokine expression following exposure to DEP likely participates in the inflammation, cellular infiltration, and increase in IgE observed in the absence of allergen.

Adult↗

Strong promoters are the key to highly efficient, noninflammatory and noncytotoxic adenoviral-mediated transgene delivery into the brain in vivo.

Using the major immediate early murine cytomegalovirus (MIEmCMV) promoter to drive expression of beta-galactosidase, we have demonstrated that, following adenoviral-mediated transduction of brain cells in vivo, a single viral infectious unit is capable of producing detectable levels of transgene expression and that gene transfer into the brain is close to 100% efficient. By reducing 100-fold the amount of virus needed to detect large numbers of transduced brain cells, we were able to completely eliminate the cellular inflammation and viral cytotoxicity associated with the delivery of adenoviral vectors into the brain compared to saline-injected controls. These results demonstrate that a strong promoter is necessary to allow the use of low concentrations of adenoviral vectors for gene transfer into the brain, thereby eliminating deleterious side effects and increasing the potential efficacy of gene therapy.

Adenoviridae↗

Increased lipid peroxidation and decreased antioxidants in lungs of guinea pigs following an allergic pulmonary response.

Oxygen-derived radicals and cytokines are known to play key roles in cellular inflammation accompanying allergic lung disease. Using a well-characterized guinea pig model of pulmonary ovalbumin (OA) hypersensitivity, we studied lipid peroxidation and endogenous antioxidant reserve in bronchoalveolar lung fluid (BAL) following a severe pulmonary allergic reaction. Since TNF-alpha is known to be involved in oxygen radical generation, we also examined TNF production in response to antigen challenge. By 24 hr after antigen challenge, the number of eosinophils in BAL was increased 3.5-fold compared with nonsensitized but challenged control animals. Immunohistochemical evaluation of BAL cells, employing a polyclonal antibody to murine TNF-alpha, demonstrated the presence of TNF in eosinophils. A 2.4-fold higher concentration of lipid peroxidation products was found in BAL fluid of sensitized and challenged vs nonsensitized, challenged guinea pigs (p < 0.05). Endogenous antioxidant levels were lower in the BAL fluid of the sensitized, challenged guinea pigs. The concentration of the major lipid-soluble antioxidant, vitamin E, was 8.7-fold lower than that in nonsensitized controls (p < 0.001) and the endogenous reserve of water-soluble antioxidants (thiols and ascorbic acid) was decreased 4-fold from that of control animals (p < 0.02). These results indicate an antioxidant/prooxidant imbalance associated with an allergic pulmonary episode.

Animals↗

Particulate matter initiates inflammatory cytokine release by activation of capsaicin and acid receptors in a human bronchial epithelial cell line.

Recent experiments have shown that human bronchial epithelial cells (i.e., BEAS-2B) release pro-inflammatory cytokines (i.e., IL-6 and TNFalpha) in a receptor-mediated fashion in response to the neuropeptides, substance P (SP), calcitonin gene-related protein (CGRP), and the prototype botanical irritant capsaicin. In the present experiments, we examined the relevance of these receptors to particulate matter (PM)-associated cellular inflammation. BEAS-2B cells, exposed to residual oil fly ash particles (ROFA), responded with an immediate (<30 s) increase in intracellular calcium levels ([Ca2+]i), increases of key inflammatory cytokine transcripts (i.e., IL-6, IL-8, TNFalpha) within 2 h exposure, and subsequent release of IL-6 and IL-8 cytokine protein after 4 h exposure. Pretreatment of BEAS-2B cells with pharmacological antagonists selective for the SP or CGRP receptors reduced the ROFA-stimulated IL-6 cytokine production by approximately 25 and 50%, respectively. However, pretreatment of these cells with capsazepine (CPZ), an antagonist for capsaicin (i.e., vanilloid) receptors, inhibited the immediate increases in [Ca2+]i, diminished transcript (i.e., IL-6, IL-8, TNFalpha) levels and reduced IL-6 cytokine release to control levels. BEAS-2B cells exposed to ROFA in calcium-free media failed to demonstrate increases of [Ca2+]i and showed reduced levels of cytokine transcript (i.e., IL-6, IL-8, TNFalpha) and IL-6 release, suggesting that ROFA-stimulated cytokine formation was partially dependent on extracellular calcium sources. A final set of experiments compared the inflammatory properties of the soluble and acidic insoluble components of ROFA. BEAS-2B cells, exposed to ROFA or ROFA that had been filtered through a 0.2-micrometer pore filter, produced equivocal IL-6. BEAS-2B cells exposed to pH 5.0 media for 15 min released moderate amounts of IL-6, 4 h later. This cytokine release could be blocked by amiloride, a pH receptor antagonist, but not by CPZ. BEAS-2B cells, pretreated with amiloride before ROFA exposure, showed a partial (approximately 25%) reduction of IL-6. Together, these data indicate that the acidic, soluble components of ROFA initiate cytokine release in BEAS-2B cells through activation of both capsaicin- and pH-sensitive irritant receptors.

Air Pollutants↗

Role of the myxoma virus soluble CC-chemokine inhibitor glycoprotein, M-T1, during myxoma virus pathogenesis.

Myxoma virus is a poxvirus that causes a virulent systemic disease called myxomatosis in European rabbits. Like many poxviruses, myxoma virus encodes a variety of secreted proteins that subvert the antiviral activities of host cytokines. It was recently demonstrated that the myxoma virus M-T1 glycoprotein is a member of a large poxvirus family of secreted proteins that bind CC-chemokines and inhibit their chemoattractant activities in vitro. To determine the biological role of M-T1 in contributing to myxoma virus virulence, we constructed a recombinant M-T1-deletion mutant virus that was defective in M-T1 expression. Here, we demonstrate that M-T1 is expressed continuously during the course of myxoma virus infection as a highly stable 43-kDa glycoprotein and is dispensable for virus replication in vitro. Deletion of M-T1 had no significant effects on disease progression or in the overall mortality rate of infected European rabbits but heightened the localized cellular inflammation in primary tissue sites during the initial 2 to 3 days of infection. In the absence of M-T1 expression, deep dermal tissues surrounding the primary site of virus inoculation showed a dramatic increase in infiltrating leukocytes, particularly monocytes/macrophages, but these phagocytes remained relatively ineffective at clearing virus infection, likely due to the concerted properties of other secreted myxoma virus proteins. We conclude that M-T1 inhibits the chemotactic signals required for the influx of monocytes/macrophages during the acute-phase response of myxoma virus infection in vivo, as predicted by its ability to bind and inhibit CC-chemokines in vitro.

Animals↗

Effects of dexamethasone in a model of lung hyperresponsiveness in the rat.

In rats, Sephadex treatment on days 0, 2 and either 4 or 5 resulted in a blood and lung eosinophilia, an increase in lung cell fragility, an increase in the functional activity of peritoneal eosinophils in vitro and a sustained increased responsiveness of lung parenchymal strips to KCl, 5-hydroxytryptamine (5-HT) and carbachol that was not associated with oedema or gross fibrosis. The corticosteroid dexamethasone, when given before each injection of Sephadex, reduced all these effects of Sephadex. When given 30 min after the last injection of Sephadex, dexamethasone had no effect on the number of blood and lung eosinophils but it did reduce the functional activity of peritoneal eosinophils, the increased lung cell fragility and the hyperresponsiveness to 5-HT. Repeated administration of dexamethasone to rats with an established hyperresponsiveness that was no longer associated with cellular inflammation had minimal effects on this hyperresponsiveness.

Animals↗

Attenuation of aortic graft arteriosclerosis by systemic administration of Allotrap peptide RDP58.

There remains no treatment for chronic allograft rejection mainly manifested by progressive arteriosclerosis. We investigated the effect of Allotrap peptide RDP58 therapy on arteriosclerosis in an aortic allotransplant model. RDP58 was administered intraperitoneally at 0.1, 0.5, or 2.5 mg/kg, every other day after transplantation. RDP58 therapy markedly inhibited vascular intimal thickening, media necrosis, and adventitial cellular inflammation. The attenuation of arteriosclerosis was associated with the induction of heme oxygenase (HO)-1 expression, inhibition of TNF-alpha production in aortic allografts, as well as decreased specific complement-dependent cytotoxic antibodies in serum. RDP58 inhibited both smooth muscle cell (SMC) proliferation with an 80% inhibition at 100 microM without evidence of cytotoxicity and TNF-induced apoptosis of SMCs in a dose-dependent fashion. These data suggest that the suppressive effect of RDP58 on allograft arteriosclerosis is due to multiple actions of the peptide, including induction of HO-1, inhibition of TNF-alpha, and a direct effect on SMC proliferation.

Animals↗

MUC1, MUC2 and MUC5AC expressions in cardiac myxoma.

BACKGROUND: Cardiac myxoma, the most common primary tumor of the heart, has a variable clinical presentation and immunohistochemical profile. An abundant mucopolysaccharidic matrix exists, including mucin, within cardiac myxoma. This investigation first reports the expressions of mucin genes in cardiac myxoma. METHODS: A retrospective study was conducted between December 1976 and February 2003, comprising 101 consecutive patients with cardiac myxoma who were treated with surgical excision. Detailed clinical parameters also were reviewed. Mucin genes, namely MUC1, MUC2 and MUC5AC, were studied immunohistochemically in 47 randomly selected patients. RESULTS: The study group contained 57 (57%) women and 44 (43%) men, with a mean age of 38+/-21 years. Their presentations included: asymptomatic (41%), dyspnea (35%), stroke (23%), chest pain (7%), fever (6%), syncope (5%) and tricuspid regurgitation (70%). The sample included 90 myxoma located in the left atrium, 3 (3%) recurrent myxoma and 8 (8%) myxoma not located in the left atrium. The myxoma did not differ with location or clinical event in terms of pathological scores, such as vascular proliferation, inflammation, cellularity, hyaline, calcification and thrombosis. Cardiac myxoma is characterized by excessive mucus secretion. Expression of membrane-associated MUC1 was considerably higher than that of the secreted mucins, MUC2 and MUC5AC (P<0.05). Furthermore, expression of MUC5AC is related to lesser embolism (P<0.05). CONCLUSIONS: This work first examined the immunohistochemical expression of mucin (MUC1, MUC2 and MUC5AC) in cardiac myxoma. This investigation then showed that the expression of representative membrane-associated mucin, MUC1, and/or secretory mucins, MUC2 and MUC5AC, in cardiac myxoma was associated with important tumor clinicopathological characteristics. Moreover, MUC5AC appears related to lesser embolism. This approach can help distinguish the potential roles of secretory mucins versus membrane-associated mucins in the development of cardiac myxoma.

Adolescent↗

What causes the antiphospholipid syndrome?

The antiphospholipid syndrome (APS) is characterized by unpredictable, sporadic, thrombotic events. The cause of the thrombosis is probably multifactorial and may involve disparate effects of the autoantibodies associated with the syndrome, which are known to interfere with various protein regulators of hemostasis. An integrated theory of pathogenesis that accounts for the diversity of autoantibodies and their effects suggests that cellular inflammation or apoptosis within the vasculature may lead to oxidation or turnover in phospholipid membranes. Thus, normally cryptic, functionally important epitopes of phospholipid-binding proteins are subjected to increased exposure to immune surveillance.

Animals↗

Regeneration of calcitonin gene-related peptide immunoreactive nerves in replanted rat molars and their supporting tissues.

First maxillary right molars in 66 rats were elevated and replanted and the pulps allowed to regenerate for 1-90 days. The contralateral tooth served as control. Regeneration of nerves in the pulp and periodontium was studied by CGRP-immunohistochemistry and the avidin-biotin-peroxidase method. The pulp and periodontium of the controls were richly supplied with CGRP-labelled nerves. One day after replantation the pulp was completely devoid of CGRP-immunoreactive nerves. After 2 days, axon sprouts were present in the apical, regenerated pulp and in the periodontium. From 3-7 days CGRP-immunoreactive axons were regularly seen to have regenerated in front of the cellular inflammation in the pulp. After 10 days, the pulps were reinnervated up to the horns, although more sparsely than in the controls. From day 20-90 there was a marked divergence in pulpal healing: 17 pulps formed irregular postoperative dentine with a gradual increase in nerve density; 16 pulps remained sparsely innervated and were gradually replaced by bone. Root resorption was most extensive in the teeth with bone replacement of pulp. The soft tissue adjacent to extensive resorbing areas had many more CGRP-labelled axons than in the controls. The reinnervation of the regenerating pulp occurred at the same time as pulpal wound healing, but did not achieve the innervation density of the controls.

Animals↗

Histologic findings of apatite-titanium complex dental implants in the jaws of dogs.

This study concerns the histologic examination of apatite-titanium complex dental implants (two-piece, cylindrical type) in dogs. There was no plaque control. One to 3 months after implantation, the surface of the apatite root was directly bound to newly formed, woven bone. Seven-and-a-half months to 1 year after implantation, the apatite root was directly bound to the newly formed lamellar bone, which provided strong bone bonding (apatite-bone bonding). There appear to be two types of mechanisms for the resorption of apatite ceramics: first, cellular-type resorption by both multinuclear and mononuclear macrophages; and second, a noncellular, fluid mechanism (dissolution). The gingival sulcus around implants and downward growth of the epithelial cells could be observed in almost all of the implants. There was no cellular inflammation in the tissue around the implants, in the nasal cavity, or in the maxillary sinus. From this study we concluded that clinical application of this dental implant system would be practical.

Animals↗

Thromboxane A2 generation by the larval cestode, Taenia taeniaeformis.

The larval stage of the tapeworm, Taenia taeniaeformis, was incubated in different concentrations of arachidonic acid. At various times after incubation, aliquots were removed for bioassay on either 38 microM aspirin or non-aspirin-treated equine platelets and by radioimmunoassay for the thromboxane A2 breakdown product, thromboxane B2 (TXB2). Platelet agonist activity was detected as early as 30 sec after addition of the arachidonic acid. In aspirin-treated platelets, this agonist activity peaked at 1 to 4 min and thereafter decayed rapidly with a time course that was both worm and arachidonic acid dependent. When assayed on non-aspirin-treated platelets the agonist activity was again detectable as early as 30 sec after addition of arachidonic acid, peaked at 1 to 3 min and then decayed very slowly over a 30-min period of incubation. It was found that levels of TXB2 were detected which increased over time concomitant with the decay of the platelet agonist activity. The most consistent detection of TXB2 generation was at 30 min with a mean of 49.6 pg and a range of 22.1 to 84.8 pg for four experiments. This report presents the first evidence for arachidonic acid utilization by a cestode or trematode and could in part provide an explanation for the marked cellular inflammation noted around dead or dying parasites.

Animals↗

Leukocyte count and bronchial hyperresponsiveness.

The relationship of total and differential blood leukocyte counts with bronchial methacholine response was studied in a population-based sample of 324 men. Geometric mean total leukocyte counts were significantly higher in reactors (6567 cells/mm3) than in nonreactors (5732 cells/mm3; p = 0.003). After adjusting for smoking habits, a factor contributing to both an elevation in peripheral leukocyte count and an increased level of airway responsiveness, reactor status remained significantly associated with leukocyte count. This association also persisted after controlling, with a logistic model, for atopy and common cold (marker of infection) and after excluding men with a history of asthma, chronic bronchitis, or low FEV1. Study of the differential leukocyte counts has shown that an increase was present for almost every type of leukocyte, and particularly evident for neutrophils. Whether these findings reflect an association between bronchial hyperresponsiveness and cellular inflammation needs more investigation.

Adult↗

Prospects for ancillary treatment of sinusitis in the 1990s.

The basis for ancillary therapy of sinusitis derives from anecdotal accounts and personal beliefs rather than definitive data. The recent appreciation that noninfectious inflammatory causes predispose to infectious sinusitis has stimulated renewed interest in developing and documenting efficacious ancillary therapies that could supplement or abrogate antibiotic use. Ancillary therapies of sinusitis could be directed toward (1) preventing viral upper respiratory tract infections (immunizations, virucidal-impregnated tissues, and proper hand-washing techniques); (2) blocking rhinoviral replication and suppressing mediator release with supraphysiologic nasal hyperthermia, although contradictory studies exist with regard to efficacy; (3) promoting sinus and nasal ventilation with both topical and oral alpha-agonists and exercise; (4) improving mucociliary clearance by reducing mucus viscosity and elasticity with saline solution irrigation, mucoregulators (N-acetylcysteine, S-carboxymethylcysteine, and iodinated glycerol), and ciliary stimulants (adenosine triphosphate); and (5) suppressing/modulating cellular inflammation (eosinophilic, basophilic, and neutrophilic) with topical nasal corticosteroid sprays and mediator antagonists. Recommendations are forwarded for future investigations of promising nonantibiotic ancillary therapies of chronic sinusitis.

Adrenergic alpha-Agonists↗

Cutaneous reactions to recombinant cytokine therapy.

Cytokines are critical to several fundamental homeostatic mechanisms such as fever, acute phase reactions, wound healing, hematopoiesis, inflammation, cellular and humoral immune responses, and tumor regression. As a result of advances in recombinant DNA technology, recombinant cytokines are available as therapeutic agents. They have been used for metastatic cancers and immunodeficiencies, as a therapy for naturally occurring or drug-induced anemias or leukopenias, and they have also been applied to some cutaneous disorders. Cytokine therapy can result in toxic reactions that affect many organ systems, especially the skin. These reactions are common and diverse, ranging from minor injection site reactions, pruritus, and flushing to life-threatening autoimmune disorders, severe erythroderma, or bullous skin reactions. This review focuses on the major cytokines that are in current clinical use or under investigation and describes the cutaneous complications of these agents.

Autoimmune Diseases↗

Aphthous stomatitis (canker sores): a consequence of high oral submucosal viscosity (the role of extracellular matrix and the possible role of lectins).

Recurrent aphthous stomatitis (RAS) or canker sores occur in 20-60% of all persons. The lesion occurs because of increased viscosity of oral submucosal extracellular matrix (ECM). The lesions begin in the second decade and peak in the third decade. Sex hormones are an important influence on fibroblasts, especially in the early phase of exposure. Sex hormones are known to concentrate, to a degree, in the bucal mucosa in animals. Lesions of RAS localize clinically and experimentally at sites of trauma. In the skin, edema is known to trigger early cellular inflammation. Increased viscosity of ECM heightens the response. The histopathology of the ulcerated lesions is similar to that which occurs under sites of acute inflammation in the skin. Systemic corticosteroids completely supress the lesions. Caustics, such as silver nitrate and phenol, stop the growth and pain of lesions. Irritants are known to break ECM viscosity. The oral mucosa exerts some control on underlying ECM. Substances such as lectins influencing the mucosa could influence ECM. Soluble substances in food or organisms could also penetrate to influence ECM. A number of different foods have been incriminated as trigger agents in individual cases. This includes gluten in patients with gluten sensitive enteropathy. Gluten is known to alter the mucosa of the small intestine in persons with celiac disease.

Extracellular Matrix↗