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D G Remick

Publications and source records attributed to D G Remick.

At least 127 records · Page 7Linked to original sources
PubMed1991

Human corneal interleukin-8. IL-1 and TNF-induced gene expression and secretion.

Corneal leukocytic infiltration is an important component of numerous ocular diseases, but specific corneal-derived leukocyte chemotaxins have not been identified. In this study, the authors identified interleukin-8 (IL-8), a known neutrophil and lymphocyte chemotaxin, to be an important chemotaxin produced by human corneal tissue. In situ hybridization and immunohistochemistry of corneas exposed to human recombinant (r) interleukin-1-beta (rIL-1 beta) or tumor necrosis factor-alpha (rTNF-alpha) revealed significant increases in corneal endothelial and stromal cell IL-8 mRNA (P less than 0.001) and marked increases in cell-associated immunoreactive IL-8 compared with unstimulated controls. ELISA assays revealed four- to eight-fold increases in corneal IL-8 secretion after 24-hour exposures to either cytokine over that obtained with unstimulated corneas (P = 0.01). In neutrophil chemotactic bioassays, significant increases in functional IL-8 were detected in media conditioned by corneas exposed to rIL-1 beta or rTNF-alpha for 24 hours (P less than 0.001). Preincubation of these corneal media with anti-IL-8 antibody significantly reduced neutrophil chemotaxis by more than 80%. These results suggest that the cornea is an active participant in ocular inflammation and raise the possibility that agents used in experimental corneal pocket models may produce indirect effects by inducing corneal secretion of other factors, such as IL-8.

Chemotaxis, Leukocyte↗
PubMed1991

In vivo biologic and immunohistochemical analysis of interleukin-1 alpha, beta and tumor necrosis factor during experimental endotoxemia. Kinetics, Kupffer cell expression, and glucocorticoid effects.

Using a model of sepsis induced by parenteral challenge of mice with bacterial lipopolysaccharide (LPS), the authors analyzed the in vivo expression of interleukin-1 (IL-1) alpha,beta and tumor necrosis factor (TNF). Both TNF and IL-1 alpha,beta were detected in hepatic sinusoidal macrophages (Kupffer cells), immunohistochemically. Kinetic analysis showed a clear sequence of synthesis. Tumor necrosis factor was produced first, reaching maximal expression at 1 hour after LPS challenge, then rapidly disappeared. IL-1 beta followed, reaching maximal expression at 2 to 3 hours, then dropped off by 6 hours. Interleukin-1 alpha expression reached a peak at 6 hours and had disappeared by 18 hours. Analysis of serum bioactivity also revealed sequential expression that correlated with immunohistochemical findings. Tumor necrosis factor was maximal at 1 hour and IL-1 at 6 hours. The IL-1 bioactivity was not due to interleukin-6 (IL-6), as this was depleted from specimens by immunoabsorption. Also IL-6 bioactivity reached maximal levels at 3 hours, earlier than IL-1. Pretreatment with 4 mg/kg dexamethasone significantly decreased Kupffer cell expression of TNF and IL-1 alpha (about 80% and 60% suppression, respectively) but had less effect on IL-1 beta expression (about 30% suppression). Accordingly, serum levels of TNF were suppressed by 75% while serum IL-1 was decreased by 39%, indicating differential sensitivity of these cytokines to glucocorticoids. Endogenous corticosteroid levels increased as TNF levels decreased, supporting the contention that glucocorticoids regulate TNF synthesis. In contrast, IL-1 levels rose concurrently with corticosterone. These data indicate a sequential activation of cytokine gene expression in vivo, which may be critical to the cascade of events leading to septic shock, and provide evidence that Kupffer cells are a major source of cytokines in endotoxemia. Finally, the differential sensitivity of cytokine expression to glucocorticoids may in part explain the inadequacy of the latter in the treatment of sepsis.

Animals↗
PubMed1990

Stimulation of alpha-adrenergic receptor augments the production of macrophage-derived tumor necrosis factor.

Accumulating evidence supports the hypothesis that neuroendocrine hormones may participate in immunologic processes. In our study we have determined that UK-14304 (UK) and norepinephrine (NE), both alpha 2-adrenergic agonists, can augment LPS-stimulated TNF from elicited macrophages (MO). The increase in TNF production was concentration dependent with an EC50 for UK and NE of 8.1 +/- 2.6 and 0.52 +/- 0.17 nM, respectively. The concentration-effect curve for UK and NE was shifted to the right by the alpha 2-antagonist yohimbine (10(-6) M), with new EC50 of 49.7 +/- 12.2 (p less than 0.001) nM and 10.3 +/- 22 nM. The augmenting effect of UK on MO TNF production was assessed over a 7 log LPS response curve. Within a single population of MO 10 nM UK shifted the LPS-induced TNF curve eightfold to the left with the greatest increase in TNF production at lower LPS concentrations. At the transcriptional level, Northern blot analysis demonstrated that UK increased LPS-induced TNF mRNA accumulation. This augmentation in TNF mRNA accumulation was blocked by yohimbine. The presence of a MO alpha-adrenergic receptor was established by demonstrating binding of the alpha 2-adrenergic antagonist 3H-yohimbine to membranes prepared from MO. This binding was rapid, saturable, reversible, and blocked by UK, clonidine, and phentolamine. These investigations support the role of alpha 2 adrenergic agonists as immunostaining compounds that may regulate cytokine production during an inflammatory response.

Animals↗
PubMed1990

Cyclosporin a modulation of tumor necrosis factor gene expression and effects in vitro and in vivo.

We investigated, in vitro and in vivo, the cyclosporin A (CsA) regulation of LPS-induced TNF gene expression and subsequent pathophysiologic changes. In vitro dose-response kinetics data showed that CsA inhibited TNF bioactivity in the supernatant without delaying its production, whereas Northern blot and in situ hybridization analysis demonstrated that CsA did not inhibit TNF mRNA expression. We then sought to examine the in vivo effects of CsA (75 mg/kg) in CBA/J mice that were primed with CFA, and injected 2 wk later with LPS. CsA demonstrated suppression of local levels (ascites) of TNF as measured by either bioactivity or an anti-murine TNF ELISA. However, CsA did not decrease mRNA for TNF, or cell-associated TNF. In vivo kinetics studies were performed to show that CsA blocked both local (ascites) and systemic (plasma) LPS-induced TNF production without delaying these effects. CsA inhibited the neutrophilia and lymphopenia that developed after the LPS challenge, but did not block the lung neutrophilic infiltrate. These observations are helpful in understanding the role of the macrophage in CsA immunosuppression, particularly with regard to the ability of CsA to block LPS-induced TNF secretion.

Animals↗
PubMed1990

Tumor necrosis factor-alpha gene expression in human whole blood.

Tumor necrosis factor-alpha (TNF) is recognized as a principal mediator of a variety of pathophysiologic and immunologic events. Lipopolysaccharide (LPS) challenge, either in vitro or in vivo, results in significant TNF production. In this study we present data demonstrating LPS-induced TNF mRNA expression and bioactivity using an in vitro tissue system of whole blood (WB). The kinetics of LPS-induced TNF production by WB was significantly accelerated as compared to isolated cultured peripheral blood monocytes (PBM). At post-LPS challenge, plasma from WB demonstrated a rapid rise in TNF bioactivity, peaking by 4 hr (1,021 units/ml/10(6) cells), plateauing between 4 and 8 hr, and then decreasing over the next 16 hr. In contrast, the highest measured TNF bioactivity from PBM did not occur until the 24-hr time-point (175 units/ml/10(6) cells). Whole blood buffy-coat TNF mRNA was assessed by Northern blot analysis, and demonstrated significant TNF mRNA accumulation at 1 hr and a peak 2 hr post-LPS challenge. By 8 hr TNF mRNA was undetectable. Concomitant administration of LPS with either prostaglandin E2 (10(-6)M) or Dexamethasone (10(-6)M) resulted in significant suppression of LPS-induced TNF production. This data supports WB as a useful in vitro medium for the molecular and cellular analysis of TNF. As specialized connective tissue, WB may provide an important environment to study the pharmacologic manipulation of TNF mRNA and bioactivity.

Blood Physiological Phenomena↗
PubMed1990

Tumor necrosis factor production and accumulation of inflammatory cells in the corpus luteum of pseudopregnancy and pregnancy in rabbits.

The potential involvement of macrophages, T lymphocytes, and the cytokine tumor necrosis factor (TNF) in regression of the corpus luteum was investigated at different stages of pseudopregnancy and pregnancy by use of immunocytochemical methods and a TNF bioassay. Few macrophages (11 +/- 6 per high power field of 8-microns frozen sections of corpus luteum, Day 10 of pseudopregnancy) were observed until the very end of pseudopregnancy, when the number of macrophages increased greatly (176 +/- 42 per high power field, Day 19 of pseudopregnancy). Pregnancy, of 32 days duration, delayed large-scale macrophage accumulation until 3 days after parturition (154 +/- 30 per high power field). Low TNF activity (approximately 1.0 U/mg protein) was detected in incubations of luteal tissue at all stages; in response to lipopolysaccharide, TNF values in medium increased 10- to 30-fold at times of luteal regression and macrophage accumulation (1 day postpartum and Day 19 of pseudopregnancy). Class II-positive T lymphocytes were observed in luteal tissue, but unlike macrophages, the number of lymphocytes did not increase at the time of regression of the corpus luteum. These data are consistent with the hypothesis that involution of the corpus luteum is promoted through the interactions of inflammatory cells and action of TNF, although the action of TNF has not been determined in this luteal tissue. Through unknown mechanisms, pregnancy postpones the accumulation of macrophages in the corpus luteum, in association with the prolongation of luteal function until the time of parturition.

Animals↗
PubMed1990

Evidence for tumor necrosis factor-induced pulmonary microvascular injury after intestinal ischemia-reperfusion injury.

Acute lung injury characterized by increased microvascular permeability is one feature of multiple-organ system failure and the adult respiratory distress syndrome. Intestinal ischemia-reperfusion injury has been linked to this type of acute lung injury. The purpose of these experiments was to examine the pathogenic mediators that link the two processes, with particular emphasis on the roles of endotoxin and tumor necrosis factor alpha (TNF alpha). Previously described characteristics of the acute lung injury in this rat model of intestinal ischemia-reperfusion include pulmonary neutrophil sequestration, depletion of lung tissue ATP, alveolar endothelial cell disruption, and increased microvascular permeability. Plasma levels of TNF in the systemic circulation of sham-operated animals and those with intestinal ischemic injury less than 60 minutes in duration were very low or undetectable. Intestinal ischemia for 120 minutes was associated with TNF elevation to 1.19 +/- 0.50 U/mL. Reperfusion for periods of 15 and 30 minutes generated 5- to 10-fold increases in circulating TNF levels (6.61 +/- 3.11 U/mL, p greater than 0.05 and 10.41 +/- 5.41 U/mL, p = 0.004 compared to sham); however this increase in circulating TNF was transient and largely cleared within 60 minutes after initiating reperfusion. Portal vein endotoxin levels were found to increase significantly before the appearance of TNF in systemic plasma, suggesting that gut-derived endotoxin may induce TNF release from hepatic macrophages into the systemic circulation. Anti-TNF antibody attenuated the increase in pulmonary microvascular permeability in this preparation but did not prevent pulmonary neutrophil sequestration. These observations suggest that endotoxin and TNF have pathogenic roles in this acute lung injury, but that mechanisms of adherence of neutrophils to endothelial cells independent of TNF may be involved. The accumulation of neutrophils in the lung but the prevention of a vascular permeability increase in the presence of antibody to TNF may imply an in vivo role for TNF in the process of neutrophil activation. These studies provide additional evidence of the importance of the endogenous inflammatory mediators in the development of systemic injury in response to local tissue injury.

Animals↗
PubMed1990

The production of tumor necrosis factor alpha and the development of a pulmonary capillary injury following hepatic ischemia/reperfusion.

The large mass of fixed macrophages resident in the liver make it a potentially rich source of cytokines. We have previously demonstrated that an isolated and severe ischemia/reperfusion injury to the liver results in cytokine release, specifically tumor necrosis factor alpha, and that TNF is then involved in the development of pulmonary pathology. This study was designed to determine the kinetics of TNF release following varying periods of hepatic ischemia and to further investigate the acute lung injury that follows. Suprahepatic blood samples were obtained at serial time points following a 45-, 60-, 75-, or 90-min ischemic insult to a segment of the rat liver with subsequent reperfusion. Using a bioassay based on the WEHI 164 cell line, plasma TNF levels were measured in all experimental animals; sham-operated control animals had undetectable levels. Changes in pulmonary capillary permeability were then measured using a standard 125I-labeled albumin washout technique following a 90-min ischemic insult with subsequent reperfusion. A significant increase in the mean permeability index was observed 9 to 12 hr following hepatic reperfusion (.601 +/- 102 as compared with .114 +/- .085 in sham-operated controls, P less than 0.005). Animals treated with anti-TNF antiserum prior to the induction of hepatic ischemia had a significantly reduced pulmonary capillary leak compared to animals pretreated with rabbit serum without TNF-blocking properties (.184 +/- .029 versus .694 +/- 052 for the control serum, P less than 0.005). TNF release follows both moderate and severe ischemic injury to the liver and the results reported here implicate TNF as an important mediator of increased pulmonary capillary permeability. These experiments confirm previous histologic studies that demonstrated pulmonary edema and intra-alveolar hemorrhage following hepatic ischemia/reperfusion, with subsequent blockade of the histologic injury by pretreatment with anti-TNF antiserum.

Animals↗
PubMed1990

Role of tumor necrosis factor-alpha in the pathophysiologic alterations after hepatic ischemia/reperfusion injury in the rat.

Cytokines are recognized as critical early mediators of organ injury. We attempted to determine whether or not severe hepatic ischemia/reperfusion injury results in tumor necrosis factor-alpha (TNF-alpha) release with subsequent local and systemic tissue injury. After 90 min of lobar hepatic ischemia, TNF was measurable during the reperfusion period in the plasma of all 14 experimental animals, with levels peaking between 9 and 352 pg/ml. Endotoxin was undetectable in the plasma of these animals. Pulmonary injury, as evidenced by a neutrophilic infiltrate, edema and intra-alveolar hemorrhage developed after hepatic reperfusion. The neutrophilic infiltrate was quantitated using a myeloperoxidase (MPO) assay; this demonstrated a significant increase in MPO after only 1 h of reperfusion. Anti-TNF antiserum pretreatment significantly reduced the pulmonary MPO after hepatic reperfusion. After a 12-h reperfusion period, there was histologic evidence of intra-alveolar hemorrhage and pulmonary edema. Morphometric assessment showed that pretreatment with anti-TNF antiserum was able to completely inhibit the development of pulmonary edema. Liver injury was quantitated by measuring serum glutamic pyruvic transaminase which showed peaks at 3 and 24 h. Anti-TNF antiserum pretreatment was able to significantly reduce both of these peak elevations. These data show that hepatic ischemia/reperfusion results in TNF production, and that this TNF is intimately associated with pulmonary and hepatic injury.

Alanine Transaminase↗
PubMed1990

WEHI 164 subclone 13 assay for TNF: sensitivity, specificity, and reliability.

Tumor necrosis factor alpha (TNF) is a peptide monokine involved in a number of immune reactions. To further understand the role of TNF in disease states it is critical to have an inexpensive, yet sensitive and specific assay. Additionally, the effects of prostaglandin E2 (PGE2), dexamethasone (dex), and cyclosporine A (CsA) on TNF gene expression have been studied, although little is known of the effects these compounds have on TNF containing samples. The aim of this study is to determine the sensitivity and specificity of a highly sensitive cell line to the actions of TNF, and to elucidate parameters which affect the stability of TNF in biological fluids. Dex and PGE2 at concentrations of 10(-5), 10(-7), and 10(-9) M, were shown not to effect the WEHI assay, and neither did CsA (10 ng/ml-1 ug/ml). The cells were not lysed by recombinant murine IL-1 alpha or beta, human recombinant IL-1 alpha or beta, human recombinant IL-2 or human recombinant IL-6 at concentrations ranging from 0.02 pg/ml to 1.0 ug/ml, or murine gamma-IFN from 100 pg/ml to 10 ng/ml. TNF containing samples with 1%-10% fetal calf serum maintained their cytolytic activity even after three freeze-thaw cycles. Serum samples did not lose any cytolytic activity with up to 11 cycles of freezing and thawing whereas, tissue culture media, containing TNF, lost significant activity with freeze-thawing. The WEHI assay has successfully detected cytolytic activity from lipopolysaccharide stimulated specimens from a number of different species. These data show the utility of this highly sensitive and specific assay. Furthermore, the WEHI assay showed a high degree of reproducibility in repeated assays.

Animals↗
PubMed1990

Theory and applications of the polymerase chain reaction.

The polymerase chain reaction (PCR) is a newly developed molecular biology technique that can significantly amplify DNA or RNA. The process consists of repetitive cycles of specific DNA synthesis, defined by short stretches of preselected DNA. With each cycle, there is a doubling of the final, desired DNA product such that a million-fold amplification is possible. This powerful method has numerous applications in diagnostic pathology, especially in the fields of microbiology, forensic science, and hematology. The PCR may be used to directly detect viral DNA, which may facilitate the diagnosis of acquired immune deficiency syndrome (AIDS) or other viral diseases. PCR amplification of DNA allows detection of specific sequences from extremely small samples, such as with forensic material. In hematology, PCR may help in the diagnosis of hemoglobinopathies or of neoplastic disorders by documenting chromosomal translocations. The new PCR opens exciting new avenues for diagnostic pathology using this new technology.

DNA↗
PubMed1990

Tumor necrosis factor-alpha, interleukin-8 and chemotactic cytokines.

There is little doubt that the high degree of communication observed during an immune response occurs via sophisticated cell-to-cell mediator circuits. The coordinate expression of specific signals are needed to orchestrate inflammation as the lesion is initiated, maintained, and finally resolved. Each of these phases can be viewed as a unique window of inflammation that is driven by a specific set of mediators. In this manuscript, we have developed the concept that cytokine-cytokine interactions play a prominent role in the elicitation of inflammatory cells. Our data demonstrate that the expression of chemotactic cytokines are both cell and stimulus specific. Interleukin-8, neutrophil chemotactic factor, can be synthesized by a variety of immune and non-immune cells, but the production is dependent upon an appropriate challenge. The production of monocyte chemotactic factor is much more cell restricted and appears to be generated in abundance by only non-immune cells (fibroblasts, endothelial cells, and epithelial cells). These data suggest that the recruitment of cells to a site of inflammation is dependent upon the expression of specific cytokines for both the induction and maintenance of the lesion.

Animals↗
PubMed1990

Endotoxin-induced cytokine gene expression in vivo. II. Regulation of tumor necrosis factor and interleukin-1 alpha/beta expression and suppression.

Tumor necrosis factor alpha (TNF alpha) mRNA is present in a preformed intracellular pool in the spleen, liver, and small bowel of naive rats. Endotoxin (Salmonella typhus lipopolysaccharide) injected intravenously induces little or no increase in whole-organ TNF mRNA levels at 15', 30', 1 degree, 2 degrees, or 4 degrees, whereas serum TNF levels are markedly elevated at 1 and 2 hours. Dexamethasone pretreatment of rats suppresses LPS-induced serum TNF concentrations, but does not suppress TNF mRNA levels in the spleen or bowel. Tachyphylaxis experiments demonstrate that a second injection of endotoxin 2 hours after an initial injection fails to induce a second peak of serum TNF, although TNF mRNA levels in the spleen and bowel remain at the levels found in naive rats. Corynebacterium parvum upregulates endotoxin-induced serum TNF release and intravenous injection of IL-1 induces the release of serum TNF but neither alters whole-organ TNF mRNA levels. Interleukin-1 alpha (IL-1 alpha) mRNA was not constitutively detected in whole-organ RNA preparations of the spleen, liver, and small bowel of naive rats. Endotoxin induces IL-1 alpha mRNA most easily appreciated in the spleen beginning at 1 hour, peaking at 2 to 4 hours, and disappearing by 6 hours. Interleukin-1 beta (IL-1 beta) mRNA was not constitutively detected in the organs examined or was present in small amounts. Endotoxin induces IL-1 beta mRNA beginning at 0.5 hours, peaking at 1 hour, and disappearing by 6 hours. Dexamethasone pretreatment prevents the LPS-induced appearance of IL-1 alpha mRNA and suppresses but does not completely inhibit the appearance of IL-1 beta mRNA. C. parvum upregulates endotoxin-induced IL-1 mRNA expression. Intravenous injection of TNF or IL-1 both induce IL-1 mRNA expression. In conclusion, TNF mRNA is constitutively expressed and TNF mRNA levels as analyzed in whole-organ RNA preparations do not change in concert with serum TNF protein levels during conditions of endotoxemia, dexamethasone treatment, tachyphylaxis, priming with C. parvum, or after injection of IL-1. In contrast, IL-1 mRNA expression during endotoxemia, dexamethasone treatment, priming with C. parvum, or after injection of TNF or IL-1 shows clear increases and decreases in whole-organ RNA preparations.

Animals↗
PubMed1990

Role of tumor necrosis factor-alpha in lipopolysaccharide-induced pathologic alterations.

Tumor necrosis factor-alpha (TNF) has been implicated strongly as a principal mediator in the pathogenesis of septic shock. The authors investigated the in vivo production of TNF in CBA/J and CD-1 mice that had been primed by an intraperitoneal injection of complete Freund's adjuvant followed 2 weeks later by an intraperitoneal injection of lipopolysaccharide (LPS). TNF bioactivity peaked in both the ascites and plasma one hour after challenge, and TNF mRNA expression in the ascites cells peaked 30 minutes after LPS. After the induction of bioactivity, an interstitial pulmonary neutrophilic infiltrate occurred that was quantitated both morphometrically and by a myeloperoxidase (MPO) assay. Peripheral blood neutrophilia and lymphopenia developed after the LPS injection (PMNs: control, 46 +/- 2%; LPS, 65 +/- 3%; Lymphs control, 53 +/- 2%; LPS, 37 +/- 3%). Treatment with dexamethasone (Dex) completely inhibited the pulmonary neutrophilic infiltrate as measured by the (MPO) assay. Because Dex will inhibit the production of several cytokines, anti-TNF antiserum was given to mice at the same time as the LPS challenge to assess specifically the role of TNF in inducing these changes. This antiserum partially blocked the pulmonary neutrophil infiltrate, and completely blocked the peripheral blood changes at one hour after LPS. These data demonstrate that TNF plays an important role in the early pathophysiologic alterations that occur after systemic exposure to LPS.

Animals↗
PubMed1989

Monocyte chemotactic protein gene expression by cytokine-treated human fibroblasts and endothelial cells.

A number of cytokines are active during the evolution of an inflammatory response, including tumor necrosis factor-alpha, interleukin-1, and novel chemotactic cytokines. This latter group of mediators belong to supergene families of inflammatory signals that play a key role in the selective recruitment of immune cells. In this presentation, we present data demonstrating, for the first time, endothelial cell expression of monocyte chemotactic protein (MCP) mRNA induced by LPS, interleukin-1 or tumor necrosis factor. Human fibroblasts were also found to express monocyte chemotactic factor mRNA in response to interleukin-1 or tumor necrosis factor, but LPS was not effective. In addition, neither primary cultures expressed MCP in response to interleukin-6. These studies demonstrate that non-immune "bystander" cells can play an active role in the recruitment of inflammatory cells via the production of novel chemotactic cytokines.

Cells, Cultured↗
PubMed1989

Monokine-induced neutrophil chemotactic factor gene expression in human fibroblasts.

Although fibroblasts are important in providing a structural framework for most tissues, they also appear to be active participants in the inflammatory process via the production of specific mediators. The production of inflammatory mediators by fibroblasts is especially important in relation to their strategic location within connective tissue as they may act as a cellular communication bridge between the interstitium and vasculature. In this paper, we demonstrate that fibroblasts may participate in these inflammatory reactions by the production of a neutrophil chemotactic factor (NCF) with characteristics similar to a recently isolated and cloned monocyte-derived NCF. Either tumor necrosis factor-alpha-, interleukin-1 alpha-, or interleukin-1 beta-stimulated fibroblasts showed both a time- and dose-dependent increase in steady-state levels of NCF mRNA and secretion of chemotactic activity. In contrast, lipopolysaccharide and interleukin-6 failed to induce fibroblast-derived NCF. The expression of fibroblast-derived NCF mRNA was first detectable by 30 min poststimulation, whereas chemotactic activity was significantly observed 3-4 h postchallenge. Heat-inactivated monokine (100 degrees C) failed to induce NCF mRNA expression, suggesting that only the active proteins are capable of inducing NCF. Gel filtration analysis using high pressure liquid chromatography indicated peak chemotactic activity with an approximate molecular mass of 8000 daltons. This peak of NCF activity was found to be relatively stable to both heat and trypsin inactivation. Specificity of the fibroblast-derived neutrophil chemotactic activity was demonstrated with inhibition of chemotaxis by the addition of neutralizing antibody directed against recombinant human neutrophil chemotactic factor. These data provide evidence that monokine-treated fibroblasts can synthesize a potent chemotactic agent with molecular and physicochemical characteristics similar to monocyte-derived NCF and that this factor may contribute to neutrophil-mediated disease processes.

Base Sequence↗
PubMed1989

Cyclosporine A inhibits TNF production without decreasing TNF mRNA levels.

The role of cytokines in health and disease has received increasing attention and numerous investigations have explored the regulation of cytokine gene expression. Tumor necrosis factor-alpha (TNF) has received particular attention because of its central role in septic shock and more recent work has shown its participation in transplant immunology. We explored the mechanism of cyclosporine A (CsA) modulation of complete Freunds adjuvant macrophage (CFA-MO) TNF gene expression. From 0.001 to 1 microgram/ml, CsA dose-dependently inhibited lipopolysaccharide (LPS) induced secreted bioactivity; at doses above 10 micrograms/ml CSA was directly toxic to CFA-MO. However, there was no suppression of TNF mRNA levels, and CsA also did not inhibit the accumulation of cell-associated TNF. Thus, CsA modulates TNF gene expression in a previously undescribed manner.

Animals↗