Acrylamide monomers in universal adhesives

OBJECTIVES

The mono-functional monomer 2-hydroxyethyl methacrylate (HEMA) is often added to universal adhesives (UAs) to improve surface wetting and prevent phase separation. Nevertheless, HEMA promotes water sorption and hydrolysis at adhesive interfaces, hereby affecting long-term bonding to dentin. This study investigated if two acrylamide monomers could replace HEMA in an UA formulation applied in etch-and-rinse (2E&R) and self-etch (1SE) bonding mode.

METHODS

Four experimental UAs were bonded to bur-cut dentin. In addition to 12 wt% 10-MDP, 25 wt% Bis-GMA and 10 wt% TEGDMA as common monomer composition, 20 %wt ethanol and 15 %wt water as solvent, and 3 wt% polymerization-related additives, the four formulations solely differed for either the acrylamide cross-linker monomer 'FAM-201' as TEGDMA alternative and HEMA replacement, the hydroxyethyl acrylamide monomer 'HEAA' as HEMA alternative, HEMA ('HEMA+'), or extra TEGDMA in a HEMA-free control ('HEMA-'), all added in a 15 wt% concentration. The split-tooth study design involved application in 2E&R mode on one tooth half versus 1SE mode on the corresponding half. Micro-tensile bond strength of half of the micro-specimens was measured upon 1-week distilled water storage ('immediate' 1w μTBS), with the other half measured after additional 6-month storage ('aged' 6 m μTBS). Statistics involved linear mixed-effects (LME) modelling (p < .05). Additionally, interfacial TEM characterization, thin-film (TF) XRD surface analysis, LogP determination, and a cytotoxicity assay were carried out.

RESULTS

FAM-201 revealed significantly higher μTBS than HEMA+ at 1w and 6 m when applied both in E&R and SE bonding modes. HEAA's μTBS was significantly lower than that of HEMA+ at 1w when applied in SE mode. TF-XRD and TEM revealed similar chemical and ultrastructural interfacial characterization, including stable 10-MDP_Ca salt nano-layering. FAM-201 was least cytotoxic and presented with an intermediary LogP, while HEAA presented with the highest LogP, indicating high hydrophilicity and water-sorption sensitivity.

SIGNIFICANCE

The acrylamide co-monomer FAM-201 could replace HEMA in an UA formulation, while HEAA not.

Erythroid and megakaryocytic differentiation of K562 erythroleukemic cells by monochloramine

The induction of leukemic cell differentiation is a hopeful therapeutic modality. We studied the effects of monochloramine (NH2Cl) on erythroleukemic K562 cell differentiation, and compared the effects observed with those of U0126 and staurosporine, which are known inducers of erythroid and megakaryocytic differentiation, respectively. CD235 (glycophorin) expression, a marker of erythroid differentiation, was significantly increased by NH2Cl and U0126, along with an increase in cd235 mRNA levels. Other erythroid markers such as γ-globin and CD71 (transferrin receptor) were also increased by NH2Cl and U0126. In contrast, CD61 (integrin β3) and CD42b (GP1bα) expression, markers of megakaryocytic differentiation, was increased by staurosporine, but did not change significantly by NH2Cl and U0126. NH2Cl retarded cell proliferation without a marked loss of viability. When ERK phosphorylation (T202/Y204) and CD235 expression were compared using various chemicals, a strong negative correlation was observed (r = -0.76). Paradoxically, NH2Cl and staurosporine, but not U0126, induced large cells with multiple or lobulated nuclei, which was characteristic to megakaryocytes. NH2Cl increased the mRNA levels of gata1 and scl, decreased that of gata2, and did not change those of pu.1 and klf1. The changes observed in mRNA expression were different from those of U0126 or staurosporine. These results suggest that NH2Cl induces the bidirectional differentiation of K562. Oxidative stress may be effective in inducing leukemic cell differentiation.

Effect of methylprednisolone on phospholipase A(2) activity and lung surfactant degradation in acute lung injury in rabbits

Glucocorticoids are the most potent and widely used anti-inflammatory agents, but they are not particularly effective against early phase of acute respiratory distress syndrome. We investigated whether methylprednisolone, a synthetic glucocorticoid, could inhibit increase of phospholipase A(2) activity in the lung and lead to protection against a model of acute respiratory distress syndrome in rabbits. Infusion of oleic acid (0.1 ml/kg/h, i.v. for 2 h) provoked pulmonary hemorrhage and edema, protein leakage and massive neutrophil infiltration, resulted in severe hypoxemia and impaired lung compliance, accompanying the increase of phospholipase A(2) activity and interleukin-8, and degradation of surfactant in the bronchoalveolar lavage fluid. Infusion of methylprednisolone (60 mg/kg/h, i.v. for 30 min before the oleic acid and then 0.5 mg/kg/h, i.v. for 6 h) did not improve the above described lung injury induced by oleic acid, nor did it suppress phospholipase A(2) activity and degradation of surfactant in bronchoalveolar lavage fluid, while it strongly reduced interleukin-8 levels in both plasma and bronchoalveolar lavage fluid. We conclude that methylprednisolone did not attenuate oleic acid-induced acute lung injury and this can be explained partly by its failure to reduce the increase of phospholipase A(2) activity and the surfactant degradation in the lung, which might also account for its clinical ineffectiveness against early acute respiratory distress syndrome.

Interleukin-1beta in antigen-induced arthritis of the rabbit temporomandibular joint

The aim was to investigate joint perfusate levels of interleukin-1beta (IL-1beta) in antigen-induced monoarthritis of the rabbit temporomandibular (TMJ) and knee joints. Twenty-four adult male New Zealand White rabbits were divided into three groups: a control group as well as TMJ arthritis and knee joint arthritis groups. After sensitization, unilateral arthritis was induced by intra-articular injection with ovalbumin and the contralateral joint was injected with saline 3 weeks after induction of arthritis. Joints were then perfused continuously with saline and samples were collected at 10-min intervals over a 50-min period. The IL-1beta concentrations in the samples were then analyzed. After killing the animals, the joints were examined histologically. The IL-1beta concentrations in the samples from the arthritic TMJs and knee joints were significantly higher than in the saline-injected and the control joints. Histological signs of chronic arthritis of similar severity were found in both joints. The IL-1beta levels in the samples from the arthritic TM and knee joints correlated with the histological severity of the arthritis, including pannus formation. In conclusion, this study shows that IL-1beta is released in the synovium of rabbit TMJs and knee joints during antigen-induced arthritis, and that high IL-1beta levels in synovial fluid are associated with histological signs of inflammation including, pannus tissue formation.

III. Chemokines and other mediators, 8. Chemokines and their receptors in cell-mediated immune responses in the lung

Chemokines constitute a large family of chemotactic cytokines that belong to a super-gene family of 8-10 kDa proteins. The chemokines are considered to be primarily beneficial in host defense against invading pathogens. However, the reactions induced by chemokines can be occasionally excessive, resulting in a harmful response to the host. Recent studies in chemokine biology have elucidated that chemokines are involved in the initiation, development, and maintenance of numbers of diseases including lung diseases. In addition to its chemotactic activity, evidence suggests that chemokines can modify the outcome of the cell-mediated immune responses by altering the Th1/Th2 cytokine profile. Chemokines are also capable of dictating the direction of specific immune responses. Chemokine action is mediated by a large super-family of G-protein coupled receptors, and the receptors are preferentially expressed on Th1/Th2 cells. Certain chemokine receptors are constitutively expressed in immune surveying cells such as dendritic cells and naive T cells. The corresponding chemokines are present in normal lymphoid tissues, suggesting a role of chemokines/receptors in cell homing and cell-cell communication in lymphoid tissue that can be an initial step for immune recognition. Thus, comprehension of the chemokine biology in immune responses appears to be fundamental for understanding the pathogenesis of T cell-mediated immune responses. The following review will highlight the current insight into the role of chemokines and their receptors in the cell-mediated immune response, with a special focus on lung diseases.

Chemokines and innate immunity

Our environment contains a great variety of infectious microbes that may be potentially destructive and threaten our survival. As soon as microbes try to establish a site of infection, the host launches a complex defense system. Innate immunity is a non-specific response and serves as the first-line of defense where phagocytes, such as neutrophils and macrophages, and NK cells play central roles in neutralizing and clearing microorganisms. Thus, migration of cells into infectious foci and subsequent activation of these cells appear to be a critical step, enabling the host to achieve effective and efficient removal of microbes. Over the past decade, chemokines have been identified as chemotactic cytokines that attract and activate specific types of leukocyte populations in vitro. There is now evidence that the magnitude of chemokines' expression in infectious diseases is strongly associated with the severity of the inflammatory responses. Blocking chemokines or their receptors with neutralizing antibodies or gene targeting technology has allowed us to understand the pathological significance of chemokines in animal models of infectious diseases. Growing evidence suggests that chemokines play an important beneficial role in immune system development, homeostasis and in innate immunity, which may pave the way for new therapeutic strategies for the treatment of infectious diseases.

Therapeutic time-window of a group IIA phospholipase A2 inhibitor in rabbit acute lung injury: Correlation with lung surfactant protection

OBJECTIVE

We attempted to determine whether group IIA secretory phospholipase A2 (sPLA2-IIA) blockade after the onset of lung injury exerted therapeutic efficacy in the treatment of oleic acid (OA)-induced acute lung injury by using S-5920/LY315920Na, a novel specific inhibitor of sPLA2-IIA, with special interest in the changes of lung surfactant.

DESIGN

Prospective animal study.

SETTING

University laboratory.

SUBJECTS

Forty Japanese white rabbits.

INTERVENTIONS

The rabbits, under anesthesia, were endotracheally intubated and mechanically ventilated and then were divided into the following groups: OA + vehicle groups, intravenous infusion of OA for the first 2 hrs (0.1 mL x kg(-1) x hr(-1)) with the addition of vehicle (1 or 2 hrs after OA administration, each n = 9, total 18 rabbits); OA + S-5920/LY315920Na groups, treated identically to the OA control with the addition of S-5920/LY315920Na (1 mg/kg bolus followed by infusion at 0.5 mg x kg(-1) x hr(-1)) after OA (1 or 2 hrs after OA administration, each n = 9, total 18 rabbits); saline control groups, treated with saline instead of OA with the addition of vehicle (1 hr after OA administration, 4 rabbits). Arterial blood gas, lung mechanics, lung inflammation, lung surfactant phospholipids, and production of inflammatory mediators in the lung were measured.

MEASUREMENTS AND MAIN RESULTS

Treatment with S-5920/LY315920Na 1 hr after OA infusion, but not 2 hrs after infusion, significantly attenuated the lung injury, as estimated by hypoxemia, decreased lung compliance, pulmonary edema, and vascular permeability. The therapeutic efficacy was similar to that found in our previous pretreatment study. The treatment after 1 hr dramatically inhibited OA-induced surfactant degradation in the bronchoalveolar lavage fluid (BALF), without affecting the concentrations of thromboxane A2, leukotriene B4, and interleukin-8 in BALF. The degree of surfactant degradation in BALF paralleled well with the severity of the lung injury. Furthermore, recombinant human sPLA2-IIA reproduced the similar hydrolysis pattern of isolated surfactant in vitro, which was inhibited by S-5920/LY315920Na.

CONCLUSIONS

Our results indicate that therapeutic blockade of sPLA2-IIA ameliorated lung dysfunction via protection of surfactant degradation in an animal model of acute lung injury, and they suggest a new strategy in treating clinical acute lung injury.

Early recruitment of neutrophils determines subsequent T1/T2 host responses in a murine model of Legionella pneumophila pneumonia

The contribution of neutrophils to lethal sensitivity and cytokine balance governing T1 and T2 host responses was assessed in a murine model of Legionella pneumophila pneumonia. Neutrophil depletion by administration of granulocyte-specific mAb RB6-8C5 at 1 day before infection rendered mice approximately 100-fold more susceptible to lethal pneumonia induced by L. pneumophila. However, this treatment did not alter early bacterial clearance, despite a substantial decrease in neutrophil influx at this time point. Cytokine profiles in the lungs of control mice demonstrated strong T1 responses, characterized by an increase of IFN-gamma and IL-12. In contrast, neutrophil-depleted mice exhibited significantly lower levels of IFN-gamma and IL-12, and elevation of T2 cytokines, IL-4 and IL-10. Immunohistochemistry of bronchoalveolar lavage cells demonstrated the presence of IL-12 in neutrophils, but not alveolar macrophages. Moreover, IL-12 was detected in lavage cell lysates by ELISA, which was paralleled to neutrophil number. However, intratracheal administration of recombinant murine IL-12 did not restore resistance, whereas reconstitution of IFN-gamma drastically improved bacterial clearance and survival in neutrophil-depleted mice. Taken together, these data demonstrated that neutrophils play crucial roles in primary L. pneumophila infection, not via direct killing but more immunomodulatory effects. Our results suggest that the early recruitment of neutrophils may contribute to T1 polarization in a murine model of L. pneumophila pneumonia.

Erythromycin attenuates an experimental model of chronic bronchiolitis via augmenting monocyte chemoattractant protein-1

The mechanisms underlying the therapeutic efficacy of erythromycin (EM) in diffuse panbronchiolitis (DPB) was investigated. For this purpose, an experimental rabbit model of DPB induced by Pseudomonas aeruginosa inoculation was employed. Daily administration of EM (3 mg x kg x day(-1)) led to an increase in the number of macrophages in bronchoalveolar lavage fluid (BALF) at an early phase, while reducing the size of granulomatous lesions at the late phase without affecting the number of viable bacteria recovered from the infected lung. Reverse transcriptase polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and immunohistochemical studies showed that monocyte chemoattractant protein (MCP)-1 was produced in both BALF and infected lung. EM treatment resulted in a significant increase in the level of MCP-1 in BALF, while reducing that of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-8. EM also increased MCP-1 messenger ribonucleic acid (mRNA) and protein expression in the infected lung. MCP-1 blockade abolished the protective effect of EM, as neutralization of MCP-1 with anti-MCP-1 antibodies reduced the EM-induced increase in the number of macrophages in BALF, and augmented size of the granulomatous lesions, as compared to control. The results of the present study suggest that erythromycin attenuates the pulmonary granuloma formation, at least in part, by increasing the production of monocyte chemoattractant protein-1.

Neutrophil infiltration as a crucial step for monocyte chemoattractant protein (MCP)-1 to attract monocytes in lipopolysaccharide-induced arthritis in rabbits

OBJECTIVE AND DESIGN

To evaluate the mechanism whereby monocyte chemoattractant protein (MCP)-1 attracts monocytes in vivo.

SUBJECTS

New Zealand white rabbits (175 rabbits) were used.

TREATMENT

LPS, MCP-1 or IL-8 was injected into knee joints. Antibodies against various cytokines or IL-1 receptor antagonist were injected to neutralize cytokine activities.

METHODS

The numbers of leukocyte populations, levels of cytokines in joints were estimated.

RESULTS

Partial inhibition of neutrophil influx with anti-IL-8 IgG (10 microg) suppressed LPS-induced macrophage influx by 43 +/- 8.5% (p<0.05) without affecting the MCP-1 level. Intraarticular injection of MCP-1 (1-30 microg) induced macrophage influx. The event was accompanied by a small number of neutrophils in an early phase. Co-injection of IL-8 (1.0 microg) enhanced the MCP-1-induced macrophage infiltration (p < 0.01). In neutrophil-depleted rabbits, LPS failed to induce macrophage influx even though the MCP-1 level was maintained, and macrophage influx following exogenously administered MCP-1 was also dramatically inhibited.

CONCLUSIONS

Early events associated with neutrophil infiltration appear to be important for MCP-1 to induce a later macrophage influx in LPS-arthritis.

Chemokine C10 promotes disease resolution and survival in an experimental model of bacterial sepsis

Previous studies have suggested that the C-C chemokine C10 is involved in the chronic stages of host defense reactions. The present study addressed the role of C10 in a murine model of septic peritonitis, induced by cecal ligation and puncture (CLP). Unlike other C-C chemokines, C10 levels in the peritoneal wash were increased approximately 30-fold above baseline levels at 48 h after CLP surgery. Immunoneutralization of peritoneal C10 levels with polyclonal anti-C10 antiserum during CLP-induced peritonitis negatively impacted mouse survival over 4 days. In contrast, when 500 ng of recombinant murine C10 was administered immediately after CLP surgery, the 4-day survival rate increased from 20% to over 60%. The C10 therapy appeared to facilitate a rapid and significant enhancement of the levels of tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein-1 (MCP-1) and a later increase in interleukin-13 (IL-13) levels in the peritoneal cavity. In vitro studies showed that the combination of IL-1beta and C10 markedly augmented TNF-alpha synthesis by peritoneal macrophages and that C10 synthesis was induced in these cells following their exposure to IL-13. At 24 h after CLP surgery, only 25% of C10-treated mice were bacteremic versus 85% of the control group that exhibited dissemination of bacteria into the circulation. The lack of bacteremia in C10-treated mice appeared to be related, in part, to in vitro evidence that C10 significantly enhanced the bacterial phagocytic activity of peritoneal macrophages. In addition, in vivo evidence suggested that C10 therapy significantly reduced the amount of material that leaked from the damaged gut. Taken together, the results of this study demonstrate that the C10 chemokine rapidly promotes disease resolution in the CLP model through its direct effects on the cellular events critically involved in host defense during septic peritonitis.

Acute effects of smoke exposure on the cellular and cytokine profile in isolated perfused lungs

The aim of this study was to assess the acute effects of cigarette smoke exposure on cellular and cytokine profile in BAL fluids in an isolated perfused rabbit assay. The experimental animals were categorized into four groups: (1) unexposed controls and (2) cigarette smoke-exposed animals perfused with autologous whole blood; (3) unexposed controls and cigarette smoke-exposed; (4) cigarette smoke-exposed animals perfused with Krebs' Ringer solution containing 5% bovine serum albumin and glucose. Cigarette smoke induced an increase in total cell numbers (mainly alveolar macrophages in BAL fluids) and an increase in the permeability index of BAL. Levels of interleukin 8 were also significantly decreased in BAL fluids due to acute effects of cigarette smoke exposure. The most likely explanation for cigarette smoke-induced increase of inflammatory cells in BAL in lungs is because of the release of pre-existing cells from reservoirs within the lungs. The acute effects of cigarette smoke-induced increase of pulmonary epithelial permeability may also play an important role in the cellular recruitment into airspaces from the lung reservoirs.

Pivotal role of the CC chemokine, macrophage-derived chemokine, in the innate immune response

Macrophage-derived chemokine (MDC), a recently identified CC chemokine, has been regarded to be involved in chronic inflammation and dendritic cell and lymphocyte homing. In this study, we demonstrate a pivotal role for MDC during experimental sepsis induced by cecal ligation and puncture (CLP). Intraperitoneal administration of MDC (1 microg/mouse) protected mice from CLP-induced lethality. The survival was accompanied by increased number of peritoneal macrophages and decreased recovery of viable bacteria from the peritoneum and peripheral blood. In addition, mice treated with an i.p. injection of MDC cleared bacteria more effectively than those in the control when 3 x 108 CFU live Escherichia coli was i.p. inoculated. Endogenous MDC was detected in the peritoneum after CLP, and neutralization of the MDC with anti-MDC Abs decreased CLP-induced recruitment of peritoneal macrophages and increased the recovery of viable bacteria from the peritoneum and peripheral blood. MDC blockade was deleterious in the survival of mice after CLP. In vitro, MDC enhanced the phagocytic and killing activities of peritoneal macrophages to E. coli and induced both a respiratory burst and the release of lysozomal enzyme from macrophages. Furthermore, MDC dramatically ameliorated CLP-induced systemic tissue inflammation as well as tissue dysfunction, which were associated in part with decreased levels of TNF-alpha, macrophage inflammatory proteins-1alpha and -2, and KC in specific tissues. Collectively, these results indicate novel regulatory activities of MDC in innate immunity during sepsis and suggest that MDC may aid in an adjunct therapy in sepsis.

Exaggerated hepatic injury due to acetaminophen challenge in mice lacking C-C chemokine receptor 2

Monocyte chemoattractant protein-1 is one of the major C-C chemokines that has been implicated in liver injury. The C-C chemokine receptor, CCR2, has been identified as the primary receptor that mediates monocyte chemoattractant protein-1 (MCP-1) responses in the mouse. Accordingly, the present study addressed the role of CCR2 in mice acutely challenged with acetaminophen (APAP). Mice genetically deficient in CCR2 (CCR2(-/-)) and their wild-type counterparts (CCR2(+/+)) were fasted for 10 hours before receiving an intraperitoneal injection of APAP (300 mg/kg). Liver and serum samples were removed from both groups of mice before and at 24 and 48 hours post APAP. Significantly elevated levels of MCP-1 were detected in liver samples from CCR2(+/+) and CCR2(-/-) mice at 24 hours post-APAP. Although CCR2(+/+) mice exhibited no liver injury at any time after receiving APAP, CCR2(-/-) mice exhibited marked evidence of necrotic and TUNEL-positive cells in the liver, particularly at 24 hours post-APAP. Enzyme-linked immunosorbent assay analysis of liver homogenates from both groups of mice at the 24 hours time point revealed that liver tissue from CCR2(-/-) mice contained significantly greater amounts of immunoreactive IFN-gamma and TNF-alpha. The in vivo immunoneutralization of IFN-gamma or TNF-alpha significantly attenuated APAP-induced liver injury in CCR2(-/-) mice and increased hepatic IL-13 levels. Taken together, these findings demonstrate that CCR2 expression in the liver provides a hepatoprotective effect through its regulation of cytokine generation during APAP challenge.

Endogenous MCP-1 influences systemic cytokine balance in a murine model of acute septic peritonitis

Sepsis and septic syndrome represent an intense systemic response with multiple physiologic and immunologic abnormalities, leading to multiple organ failure. Recent investigations suggest that the critical conditions are balanced by endogenous cytokines. In the present study, we examined the involvement of endogenous monocyte chemoattractant protein (MCP)-1 in the regulation of cytokine production in tissue/organs in a murine model of acute septic peritonitis induced by cecal ligation and puncture (CLP). Initial studies showed that CLP induced elevated levels of MCP-1 in tissues, such as liver, lung, and kidney. To neutralize endogenous MCP-1, either anti-MCP-1 antibodies or control antibodies were intraperitoneally administered 2 h prior to CLP. Administration of anti-MCP-1 antibodies resulted in a decrease in the level of interleukin (IL)-13 in tissues, while increasing the level of tumor necrosis factor-alpha, compared to control. In addition, anti-MCP-1 treatment decreased the level of IL-12 and, in contrast, increased the level of IL-10 in specific tissues. These findings suggest that endogenous MCP-1 influences the cytokine balance in tissues in favor of anti-inflammatory and immune-enhancing cytokines, probably protecting the host from tissue/organ damage during sepsis.

Therapeutic use of chemokines

Chemokines are involved in a number of pathological processes, and therefore represent important targets. However, it has also become apparent that chemokines have exciting therapeutic applications in inflammatory, infectious and cancer-related diseases. The following review will highlight the application of novel therapies including viral-encoded, recombinant, and genetically engineered chemokines to a number of diseases or disorders. Advances in the application of novel chemokine delivery procedures both at the research bench and the clinical bedside will also be discussed. Overall, the utilization of chemokines to prevent and treat disease has tremendous potential.

Lazaroid reduces production of IL-8 and IL-1 receptor antagonist in ischemic spinal cord injury

BACKGROUND

21-aminosteroids (lazaroids) have demonstrated the protective effect against cerebral ischemic injury through the inhibition of lipid peroxidation. We examined whether lazaroids affected the production of proinflammatory and antiinflammatory cytokines in ischemic spinal cord injury model.

MATERIALS

Anesthetized New Zealand white rabbits underwent a 20-minute infrarenal aortic cross-clamping (AXC) with pretreatment of either an intravenous 3 mg/kg lazaroid U74389G (group L; n = 10) or the same volume saline (group P; n = 10). Sham operation group (group S; n = 6) underwent only exposure of the aorta. Plasma concentrations of interleukin (IL)-8, -1beta, -1 receptor antagonist (IL-1ra) and tumor necrosis factor (TNF)-alpha were measured at four time points. Functional assessment with Tarlov score at 24 and 48 hours after pretreatment, pathologic assessment of the spinal cord, and measurements of cytokine levels in the spinal cord were performed.

RESULTS

The maximum elevation of plasma IL-8 and -1ra levels occurred at 1 hour after declamping in four measurement points. Plasma IL-8 and -1ra levels in group L were significantly lower than those in group P (*p < 0.05). Plasma TNFalpha peaked at 5 minutes after declamping, but decreased afterwards. Plasma TNFalpha levels were not different among three groups. Spinal IL-8 levels in group L (0.98 +/- 0.34 ng/g tissue) were lower than those in group P (7.26 +/- 2.26 ng/g tissue)(*p < 0.05). Spinal IL-1ra and TNFalpha were not significantly different. Tarlov score and pathologic assessment were better in group L.

CONCLUSIONS

Lazaroid U-74389G reduced the production of systemic IL-8 and -1ra and spinal IL-8 when AXC caused spinal cord injury. These results indicate that lazaroids may attenuate ischemic endothelial cell injury or activation of leukocytes.

Expression and contribution of endogenous IL-13 in an experimental model of sepsis

IL-13 has been shown to exert potent anti-inflammatory properties. In this study, we elucidated the functional role of endogenous IL-13 in a murine model of septic peritonitis induced by cecal ligation and puncture (CLP). Initial studies demonstrated that the level of IL-13 increased in tissues including liver, lung, and kidney, whereas no considerable increase was found in either peritoneal fluid or serum after CLP. Immunohistochemically, IL-13-positive cells were Kupffer cells in liver, alveolar macrophages in lung, and epithelial cells of urinary tubules in kidney. IL-13 blockade with anti-IL-13 Abs significantly decreased the survival rate of mice after CLP from 53% to 14% on day 7 compared with control. To determine the potential mechanisms whereby IL-13 exerted a protective role in this model, the effects of anti-IL-13 Abs on both local and systemic inflammation were investigated. Administration of anti-IL-13 Abs did not alter the leukocyte infiltration and bacterial load in the peritoneum after CLP but dramatically increased the neutrophil influx in tissues after CLP, an effect that was accompanied by significant increases in the serum levels of aspartate transaminase, alanine transaminase, blood urea nitrogen, and creatinine. Tissue injury caused by IL-13 blockade was associated with increases in mRNA and the protein levels of CXC chemokines macrophage inflammatory protein-2 and KC as well as the CC chemokine macrophage inflammatory protein-1alpha and the proinflammatory cytokine TNF-alpha. Collectively, these results suggest that endogenous IL-13 protected mice from CLP-induced lethality by modulating inflammatory responses via suppression of overzealous production of inflammatory cytokines/chemokines in tissues.

Adenoviral-mediated overexpression of monocyte chemoattractant protein-1 differentially alters the development of Th1 and Th2 type responses in vivo

The expression of chemokines during an immune response may participate in determining the intensity and type of the developing immune response. In the present study, we have examined the effect of overexpressing monocyte chemoattractant protein (MCP)-1 at the site of immunization during different stages of Th1- and Th2-type granulomatous responses. The overexpression of MCP-1 by MCP-1 adenovirus during the sensitization phase of the purified protein derivative Th1-type model significantly reduced the elicitation of the granulomatous response. In contrast, the overexpression of MCP-1 during the sensitization phase of the schistosome egg Ag Th2 response led to an enhanced granulomatous reaction. When cytokines were examined upon restimulation of splenocytes ex vivo, an altered cytokine profile was observed, as compared with control mice. IFN-gamma and IL-12 were significantly reduced in the purified protein derivative Th1-type response, whereas IL-10 and IL-13 were up-regulated in the schistosome egg Ag Th2-type response. The regulation of the immune response was further examined by using the MCP-1 adenovirus at later time points during the elicitation phase. When MCP-1 was overexpressed during the elicitation phase of the responses, neither the Th1-type nor the Th2-type granuloma was altered. Likewise, the cytokine profiles after restimulation of splenocytes ex vivo were unchanged. Thus, the function of MCP-1 may depend on the stage and type of immune response.

CXC chemokine GRO is essential for neutrophil infiltration in LPS-induced uveitis in rabbits

The purpose of this study was to investigate the role and regulation of the CXC chemokine GRO and the interaction between GRO and IL-8 in LPS-induced uveitis in rabbits. Uveitis was induced by intravitreal injection of 100 ng of LPS in rabbits. After the LPS injection, GRO was produced in aqueous humor and peaked at 24 hr. Immunohistochemistry showed that ciliary epithelial cells were responsible for production of GRO. Blocking the activity of GRO by anti-GRO serum reduced LPS-induced aqueous neutrophil counts by 80%, but did not reduce the mononuclear cell counts or protein levels or IL-8 levels. Regulation of GRO production by TNFalpha, IL-1 and IL-8 was studied. Anti-TNFalphamAb alone did not inhibit the 24 hr LPS induced GRO levels, whereas rrIL-1Ra inhibited the GRO production by 58%. The combination of anti-TNFalpha mAb and rrIL-1Ra inhibited 93% of GRO production. Although treatment with anti-IL-8 IgG inhibited the neutrophil infiltration by 66%, treatment with this antibody did not inhibit GRO production. Taken together, our results suggest that GRO is an essential mediator for neutrophil infiltration in LPS-induced uveitis in rabbits. Most of GRO production is mediated by TNFalpha and IL-1. GRO and IL-8 act in concert to mediate neutrophil infiltration.

Endogenous monocyte chemoattractant protein-1 (MCP-1) protects mice in a model of acute septic peritonitis: cross-talk between MCP-1 and leukotriene B4

We investigated the involvement of monocyte chemoattractant protein (MCP)-1 in a murine model of septic peritonitis induced by cecal ligation and puncture (CLP). Initial studies demonstrated that CLP induced a dramatic increase in MCP-1 production in the peritoneum, followed by an increase in the recruitment of leukocytes. MCP-1 blockade with anti-MCP-1 antiserum significantly decreased the survival rate following CLP, which was accompanied by an enhanced recovery of viable bacteria from the peritoneum. This was likely due to the reduction in the recruitment and activation of both macrophages and neutrophils. To understand the mechanisms whereby MCP-1 may influence neutrophil infiltration, levels of chemokines known to attract neutrophils were monitored, which showed that peritoneal levels of macrophage-inflammatory protein (MIP)-2, KC, and MIP-1alpha were not altered with anti-MCP-1 Abs. However, anti-MCP-1 Abs reduced the peritoneal levels of leukotriene B4 (LTB4) by 59%. The i.p. injection of MCP-1 into normal mice resulted in elevated levels of LTB4 in the peritoneum. In vitro, MCP-1 stimulated the production of LTB4 from peritoneal macrophages, in a dose-dependent manner. A specific LTB4 receptor antagonist (CP-105, 696) inhibited CLP-induced recruitment of both neutrophils and macrophages, which was accompanied by a reduced level of MCP-1 in the peritoneum. Finally, administration of CP-105,696 was extremely detrimental to the survival of mice following CLP. These experiments demonstrate that endogenous MCP-1 serves as an indirect mediator to attract neutrophils via the production of LTB4, and suggest the cross-talk can occur between MCP-1 and the lipid mediator LTB4 during septic peritonitis.

Increased interleukin-1 (IL-1) and imbalance between IL-1 and IL-1 receptor antagonist during acute inflammation in experimental Shigellosis

Infection by the enteric bacterial pathogen Shigella results in intense mucosal inflammation and destruction of the colonic and rectal epithelium in infected humans. Initial bacterial translocation occurs through the follicle-associated epithelium. Previous experiments suggest that interleukin-1 (IL-1) is crucial to trigger inflammation, particularly in the follicular zones. During the first 4 hours of infection in a rabbit ligated-loop model of intestinal invasion, there are two salient characteristics: (i) a high concentration of IL-1alpha and IL-1beta, both in infected Peyer's patch tissue and in the corresponding efferent mesenteric blood, and (ii) a very low level of expression of IL-1 receptor antagonist (IL-1ra). These may reflect a combination of regulation of expression and secretion of IL-1alpha, IL-1beta, and IL-1ra by both resident and recruited phagocytes and the induction of mononuclear phagocyte apoptosis by Shigella. This low IL-1ra/IL-1 ratio likely accounts for the rapid, uncontrolled inflammation characteristic of shigellosis.

Crucial role of group IIA phospholipase A(2) in oleic acid-induced acute lung injury in rabbits

Group IIA secretory phospholipase A(2) (sPLA(2)) has been implicated in a variety of inflammatory diseases including acute lung injury (ALI); however, the role of sPLA(2) in this disorder remains unclear. The aim of the present investigation was to examine the role of this enzyme in a model of ALI induced by oleic acid (OA) in rabbits by testing human group IIA phospholipase A(2) (PLA(2)) inhibitor, S-5920/LY315920Na. Experimental groups consisted of a saline control group (n = 8), an OA control group (n = 10) infused intravenously with OA (0.1 ml/kg/h for 2 h), and three groups given OA + S-5920/LY315920Na (three different doses, n = 8, respectively). Infusion of OA provoked pulmonary hemorrhage and edema formation, protein leakage, and massive neutrophil infiltration, resulting in severe hypoxemia and impaired lung compliance. PLA(2) activity was detected in the bronchoalveolar lavage fluid (BALF), but not plasma, which correlated well with severity of lung injury in this model. Pretreatment with S-5920/LY315920Na diminished the OA-induced PLA(2) activity in the BALF and dose-dependently attenuated the previously described lung injury induced by OA, accompanied by protection against lung surfactant degradation and production of thromboxane A(2) (TXA(2)) and leukotriene B(4) (LTB(4)). S-5920/LY315920Na also inhibited the OA-induced production of interleukin-8 (IL-8), both in plasma and BALF. Thus, sPLA(2) appears to play a key role in OA-induced lung injury, suggesting that the group IIA PLA(2) inhibitor may be a promising agent for patients with acute respiratory distress syndrome (ARDS).

Dermatomyositis with elevated serum hyaluronate

We report two Japanese patients with dermatomyositis whose serum hyaluronate levels were correlated with their disease activities. The diagnosis of one patient was primary idiopathic dermatomyositis, and that of the second patient was dermatomyositis associated with neoplasia. The serum hyaluronate level of the former patient was decreased by systemic corticosteroid therapy, and that of the latter patient decreased following the surgical resection of mammary carcinoma and subsequent chemotherapy. The disease activity of each patient was greatly improved after these therapies. The longitudinal measurement of serum hyaluronate concentration may be useful to estimate the disease activity of patients with dermatomyositis whose initial serum levels of hyaluronate are elevated.

Involvement of growth-related protein in lipopolysaccharide-induced rabbit arthritis: cooperation between growth-related protein and IL-8, and interrelated regulation among TNFalpha, IL-1, IL-1 receptor antagonist, IL-8, and growth-related protein

We investigated the functional role of a CXC chemokine, growth-related protein (GRO), in the recruitment of neutrophils in lipopolysaccharide (LPS)-induced rabbit arthritis. The amounts of GRO in the synovial fluids (SF) reached the first peak (major) at 2 hours and the second peak (minor) at 9 hours after injection of LPS into the knee joints. Administration of anti-GRO mouse monoclonal antibody inhibited 54% of the peak leukocyte accumulation at 9 hours (neutrophils greater than 95%), which was similar to the inhibition by anti-IL-8 IgG (48%). Co-administration of these inhibitors increased the inhibition up to 70% at 9 hours and also inhibited 65% of the initial phase of leukocyte infiltration at 2 hours (neutrophils greater than 99%), which was not affected by a single administration of each inhibitor. The amounts of GRO in SF at 2 hours were not altered by either anti-TNFalpha mAb or anti-IL-8 IgG, but reduced by rabbit recombinant IL-1 receptor antagonist (rrlL-1Ra) by 39%. The inhibition by rrlL-1 Ra was augmented further to 59% with coadministered anti-TNFalpha mAb. In contrast, the amounts of GRO at 9 hours were reduced by rrlL-1Ra by 67%. There was no additional reduction in the amounts of GRO at 9 hours by either combination of rrlL-1Ra with anti-TNFalpha mAb or anti-IL-8 IgG. Administration of anti-GRO mAb did not alter TNFalpha or IL-8 contents in SF at their peak (2 hours), but reduced the amounts of IL-1beta at 6 hours and IL-1Ra at 9 hours by 42% and 49%, respectively. These results provide evidence for the following: (a) GRO as well as IL-8 are important mediators involved in the recruitment of neutrophils both in the early and the late phase of LPS-induced arthritis, (b) IL-1 produced in the early phase stimulates GRO production, (c) GRO plays a role in the later induction of IL-1beta and IL-1Ra, and (d) induction of GRO is not regulated by IL-8.

Neutrophils as a source of cytokines in inflammation

The recruitment of neutrophils into inflammatory foci is a fundamental process observed in inflammation. The function of neutrophils has long been regarded only as an effector cell that kills the invading pathogens. Recent evidence has demonstrated that neutrophils are capable of producing inflammatory cytokines. The findings are, however, mainly based on the findings obtained in vitro. It has not been fully elucidated if neutrophils could synthesize and secrete cytokines in vivo. Animal models of inflammation are essential to address the issue and provide insight into the involvement of neutrophils in producing cytokines.

Functional roles of MCP-1 in Propionibacterium acnes-induced, T cell-mediated pulmonary granulomatosis in rabbits

The immunological manifestation of granuloma formations in humans largely depends on the delayed-type hypersensitivity response. We investigated the involvement of monocyte chemoattractant protein-1 (MCP-1) in a rabbit model of T cell-mediated pulmonary granulomatosis. Intravenous injection of Propionibacterium acnes (P. acnes) into sensitized rabbits induced massive and diffuse pulmonary granulomas. Levels of MCP-1 in sera and bronchoalveolar lavage fluids (BALF) peaked before the granuloma formation reached the peak (on days 1 and 3 after challenge, respectively). Chemotactic activities toward monocytes and T cells in BALF were inhibited by anti-MCP-1 IgG by 80 and 36%, respectively. The phenotypic analysis of the migrating T cells revealed that activated and memory T cells rather than naive cells were preferentially attracted to the BALF. Administration of anti-MCP-1 antiserum inhibited the development of granuloma formation in both size and number, the numbers of infiltrating leukocytes in BALF, the expression of adhesion molecules on peripheral monocytes/T cells, and on macrophages/T cells in BALF, and the production of TNF-alpha in the lung. Anti-MCP-1 resulted in a trend toward decreased level of IL-1beta in the lung. The inhibition of the production of these cytokines appeared to be induced indirectly through the inhibition of the recruitment of macrophages that produce these cytokines. The results suggest important roles of MCP-1 in the development of granuloma formation in this model through the attraction and activation of specific types of cells.

Role and regulation of IL-8 and MCP-1 in LPS-induced uveitis in rabbits

Intravitreal injection of lipopolysaccharide (LPS) induces leukocyte infiltration and protein leakage into the aqueous humor. In the present study, we investigated the role of IL-8 and MCP-1 and regulation of these chemokines by TNFalpha and IL-1 in LPS-induced uveitis in rabbits. After intravitreal injection of LPS, generation of IL-8 in the aqueous humor showed a biphasic pattern with the first peak at 12 hr and the second one at 24 hr, while MCP-1 was produced in a monophasic pattern and peaked at 24 hr. Immunohistochemistry showed that ciliary epithelial cells and infiltrating leukocytes were the producing cells of IL-8 and MCP-1. Administration of anti-IL-8 IgG suppressed by 66% the peak levels of LPS-induced aqueous neutrophil counts at 24 hr but did not suppress aqueous mononuclear cell counts or protein levels. anti-MCP-1 IgG inhibited aqueous mononuclear cell counts by 41% and protein levels by 28%, but did not inhibit aqueous neutrophil counts. The levels of LPS-induced aqueous IL-8 and MCP-1 at 12 hr were inhibited by anti-TNFalpha mAb but not by an IL-1 receptor antagonist (IL-1Ra), while concentrations of the two chemokines at 24 hr were inhibited by both anti-TNFalpha mAb and IL-1Ra. A combination of anti-TNFalpha mAb and rrIL-1Ra had an additive effect on the 24 hr-chemokine levels and inhibited up to 90% chemokine production. Taken together, our results show that IL-8 mediates neutrophil infiltration, while MCP-1 mediates mononuclear cell infiltration and protein leakage in LPS-induced uveitis in rabbits. Levels of aqueous IL-8 and MCP-1 at 12 hr are regulated by TNFalpha, while levels at 24 hr are regulated by TNFalpha and IL-1.

Analysis of the cytokine interaction among interleukin-1beta, interleukin-8, and interleukin-1 receptor antagonist in the rabbit ovulatory process

OBJECTIVE

To elucidate the regulation and involvement of interleukin (IL)-1beta, IL-8, and IL-1 receptor antagonist in the hCG-induced rabbit ovulatory process.

DESIGN

Randomized, controlled animal study.

SETTING

University research laboratory.

ANIMAL(S)

Mature female New Zealand white rabbits.

INTERVENTION(S)

After i.v. administration of 100 IU of hCG to rabbits, ovarian levels of IL-1beta. IL-8, and IL-1 receptor antagonist were determined at indicated times by ELISA. Anti IL-1beta, anti-lL-8, or anti-IL-1 receptor antagonist antiserum was given i.v. 30 minutes before hCG injection.

MAIN OUTCOME MEASURE(S)

Effects of each antiserum on the levels of the other cytokines and neutrophil accumulation, assessed by myeloperoxidase activity, were determined. Ovulation rate (rate of ruptured follicles) was also evaluated.

RESULT(S)

The maximal level of IL-8 was detected at 4 hours. which preceded that of IL-1beta and IL-1 receptor antagonist, detected at 6 hours after hCG injection. Administration of anti-IL-1beta antiserum resulted in a statistically significant reduction of the peak levels of IL-8 and IL-1 receptor antagonist. Administration of anti-IL-8 antiserum reduced the accumulation of IL-1beta and IL-1 receptor antagonist. Anti-IL-1 receptor antagonist antiserum significantly augmented the accumulation of IL-1beta and IL-8. Myeloperoxidase activity was reduced by anti-IL-8 antiserum. Anti-IL-1beta and anti-lL-8 antiserum reduced the hCG-induced ovulation rate, but a synergistic effect was not evident when these antisera were injected simultaneously. Anti-IL-1 receptor antagonist antiserum had no apparent effect on ovulatory efficiency.

CONCLUSION(S)

IL-1beta, IL-8, and IL-1 receptor antagonist may affect the accumulation of related cytokines in ovaries and may be involved in ovulation.

Sequential generation of cytokines during the initiative phase of inflammation, with reference to neutrophils

Studies have suggested the role of cytokines in inflammation, as determined by results obtained in vitro, or with assessments of clinical samples. However, extrapolation of in vitro results to an in vivo situation must be made with caution, and findings obtained from clinical samples tend to lack a causal relation between cytokines and inflammatory responses. Animal models of inflammation can be useful in understanding roles of cytokines at sites of inflammation. We examined the production kinetics and cellular sources of tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta, IL-8, and IL-1 receptor antagonist (IL-1Ra), and obtained evidence for the involvement of these cytokines in a rabbit model of arthritis induced by lipopolysaccharide (LPS). We also attempted to analyze the inflammatory cytokine network among TNFalpha, IL-1beta, IL-8, and IL-1Ra. Understanding the role of cytokines in animal models paves the way to a better understanding of disease in humans.

Production and regulation of monocyte chemoattractant protein-1 in lipopolysaccharide- or monosodium urate crystal-induced arthritis in rabbits: roles of tumor necrosis factor alpha, interleukin-1, and interleukin-8

The production of monocyte chemoattractant protein-1 (MCP-1) and its regulation by TNFalpha, IL-1, and IL-8 were investigated in two rabbit models of arthritis induced by intra-articular injection of lipopolysaccharide (LPS) or monosodium urate (MSU) crystals. We first prepared recombinant rabbit MCP-1 and antibodies and then developed an immunoassay. The immunoassay detected 3 pg/ml rabbit MCP-1 and did not cross-react with other rabbit chemokines such as IL-8 or GRO. MCP-1 was first detected in synovial fluid (SF) at 1 hour, and peaked at 4 or 2 hours after the injection of LPS or MSU crystals, respectively. Immunohistochemically, MCP-1 was detected in synovial lining cells and infiltrating neutrophils. The amounts of MCP-1 detected in SF from neutrophil-depleted rabbits were similar to those in normal rabbits, suggesting that synovial lining cells were the main source of MCP-1 detected in SF. The peak level of MCP-1 in SF after LPS-injection was inhibited by 57% with anti-TNFalpha mAb and by 41% with IL-1 receptor antagonist (IL-1Ra). Coadministration of anti-TNFalpha mAb and IL-1Ra inhibited 90% of MCP-1 production. In contrast, the peak level of MCP-1 in SF after MSU crystal-injection was not affected by any cytokine inhibitor, but was reduced by 52% with coadministration of anti-TNFalpha mAb and IL-1Ra. Anti-IL-8 IgG had no effect on the production of MCP-1 in either model. Thus, the production of MCP-1 in LPS-induced arthritis was mostly regulated by TNFalpha and IL-1, whereas half the extent of MCP-1 production in MSU crystal-induced arthritis was independent of TNFalpha or IL-1. IL-8 does not seem to regulate the production of MCP-1 in SF either directly or indirectly. Finally, administration of neutralizing anti-MCP-1 antibody inhibited LPS- and MSU crystal-induced monocyte infiltration by 58.4% and 44.9%, respectively, suggesting that synovial production of MCP-1 plays an important role in the recruitment of monocytes in these arthritis models.

Analysis of the cytokine network among tumor necrosis factor alpha, interleukin-1beta, interleukin-8, and interleukin-1 receptor antagonist in monosodium urate crystal-induced rabbit arthritis

In the present study, we analyzed the cytokine network among TNFalpha, IL-1beta, IL-8, and IL-1 receptor antagonist (IL-1Ra) in a rabbit experimental model of acute gout. The production of TNFalpha in synovial fluids reached the peak at 2 hours after the intra-articular injection of monosodium urate (MSU) crystals. The production of IL-1beta and IL-8 reached the first peak at 2 hours and the second peak at 9 and 12 hours, respectively. The production of endogenous IL-1Ra reached the peak at 9 hours. The source of TNFalpha and the first phase of IL-8 was synovial cells, whereas infiltrating leukocytes were the source of the second phase of IL-8 and also of IL-1beta and IL-1Ra. The production of TNFalpha was not altered by either anti-lL-8 IgG or IL-1Ra. The first IL-1beta peak was reduced only with a combination of anti-TNFalpha mAb and anti-lL-8 IgG, whereas the second peak was significantly reduced by either inhibitor. The first IL-8 peak was not altered with anti-TNFalpha mAb or IL-1 Ra, whereas the second IL-8 peak was reduced with IL-1Ra. Anti-TNFalpha mAb or anti-lL-8 IgG significantly reduced the peak level of endogenous IL-1Ra. These cytokine inhibitors also attenuated the maximal leukocyte accumulation at 9 hours, but not the initial phase, which occurred within 2 hours. These results provide evidence that IL-8 and TNFalpha were responsible for the production of IL-1beta and IL-1Ra, and that IL-1beta was responsible for the second phase of IL-1beta and IL-8 production. Our data also suggest that the initial and the maximal phases of leukocyte influx are differently regulated. Finally, the intravenous injection of colchicine inhibited neutrophil infiltration without affecting the production of TNFalpha or the first peak of IL-8, suggesting that colchicine inhibits MSU crystal-induced arthritis by directly inhibiting the migration of neutrophils.

Involvement of TNF alpha, IL-1 beta and IL-1 receptor antagonist in LPS-induced rabbit uveitis

The objective of the study was to investigate involvement of TNF alpha, IL-1 beta and IL-1 receptor antagonist (IL-1Ra) in lipopolysaccharide (LPS)-induced uveitis. Intravitreal injection of LPS (100 ng) to rabbits induced a massive leukocyte infiltration and protein leakage into the aqueous humor. Aqueous leukocyte counts and protein levels reached a peak 24 hr after this injection. The peak concentrations of aqueous TNF alpha (230 +/- 37 pg ml-1, at 9 hr) and IL-1 beta (185 +/- 80 pg ml-1, at 18 hr) preceded peak levels of aqueous leukocyte counts and protein levels. In contrast, the levels of aqueous IL-1Ra peaked at 48 hr (12,239 +/- 1964 pg ml-1) and a fairly high concentration of IL-1Ra remained when the inflammatory reactions subsided. Immunohistochemistry and leukocyte-depletion studies showed that infiltrating leukocytes were the major cellular sources of aqueous TNF alpha, IL-1 beta and IL-1Ra. Intravitreal injection of homologous TNF alpha (0.1-1.5 micrograms) or IL-1 beta (0.5-5 ng) reproduced a rapid leukocyte infiltration and protein leakage. Administration of anti-TNF alpha mAb (10 micrograms) suppressed the number of LPS-induced infiltrating neutrophils by 50%, mononuclear cells by 58%, and protein leakage by 42%. Administration of rabbit IL-1Ra (10 micrograms) also suppressed neutrophil influx by 78%, however, neither mononuclear cell influx nor protein leakage was inhibited by rabbit IL-1Ra. Co-administration of the two inhibitors enhanced inhibition of neutrophil infiltration to 88%, and protein leakage to 64%. We conclude that TNF alpha and IL-1 beta are the principal mediators of LPS-induced uveitis. Our observations also suggest that endogenous IL-1Ra may down-regulate inflammatory reactions.

IL-8 is an essential mediator of the increased delayed-phase vascular permeability in LPS-induced rabbit pleurisy

We investigated the involvement of IL-8 in the delayed vascular permeability (VP) in rabbit lipopolysaccharide (LPS)-pleurisy. Maximal level of interleukin-8 (IL-8) was detected in pleural fluid at 2 h after LPS injection and anti-IL-8 inhibited the delayed VP by 90%. Injection of homologous IL-8 induced VP, the time-course of which preceded that of LPS-induced delayed VP. Production of IL-8 in LPS-pleurisy was inhibited with anti-tumor necrosis factor alpha (TNF-alpha), whereas the production of TNF-alpha was not affected with anti-IL-8. Injection of IL-8 did not induce TNF-alpha production and anti-TNF-alpha had no effect on IL-8-induced VP. Injection of homologous TNF-alpha induced IL-8 production and VP, and TNF-alpha-induced delayed VP was blocked with anti-IL-8. These results indicate important roles of IL-8 in LPS-induced delayed VP and that TNF-alpha causes the delayed VP through the production of IL-8.

Interleukin-8 as an essential factor in the human chorionic gonadotropin-induced rabbit ovulatory process: interleukin-8 induces neutrophil accumulation and activation in ovulation

The objective of our study was to elucidate the involvement of interleukin (IL)-8 in the hCG-induced rabbit ovulatory process. After administering hCG (100 IU i.v.), we examined myeloperoxidase (MPO) activity, which represents neutrophil accumulation; neutrophil elastase (NE) activity, which is an indicator of neutrophil activity; and levels of IL-8 in the ovaries. The maximal level of IL-8 was observed before MPO and NE activities reached a peak: production of IL-8, MPO, and NE activities peaked, respectively, at 4 h (5.58 +/- 0.88 pg/mg ovary, n = 13), 6 h (1.07 +/- 0.13 deltaA/min per gram ovary, n = 8), and 9 h (18.89 +/- 1.05 U/g ovary, n = 8). Anti-rabbit IL-8 antiserum given i.v. significantly reduced the maximal levels of hCG-induced MPO activity (antiserum vs. control; 0.34 +/- 0.04 vs. 1.12 +/- 0.11 deltaA/min per gram ovary, n = 14, p < 0.001) and NE activity (8.14 +/- 0.85 vs. 18.30 +/- 0.79 U/g ovary, n = 14, p < 0.001). The hCG-induced ovulation rate was significantly inhibited by the antiserum (50.5% vs. 83.9%, n = 14, p < 0.001). Intraperitoneal injection of 100 mg/kg of ONO-5046, a specific NE inhibitor, also attenuated the ovulation rate (ONO-5046 vs. vehicle; 56.0% vs. 74.0%, n = 14, p < 0.05). These findings clearly indicate that IL-8 has an important role in the hCG-induced ovulatory process through the accumulation and activation of neutrophils.

IL-8 is involved in homologous TNF alpha-, but not in IL-1 beta-induced neutrophil infiltration in rabbits

OBJECTIVE AND DESIGN

We examined the involvement of IL-8 in TNF alpha and IL-1 beta neutrophil infiltration, using homologous reagents.

SUBJECTS

Female New Zealand white rabbits (n = 211).

METHODS

After injection of TNF alpha (1 microgram) or rrIL-1 beta (300 pg) into rabbit knee joints, the leukocyte influx and the production of IL-8 were estimated. Anti-TNF alpha mAb, rrIL-1Ra, and anti-IL-8 IgG (10 micrograms each) were administrated simultaneously with either TNF alpha or IL-1 beta.

RESULTS

Administration of TNF alpha or IL-1 beta induced IL-8 production; both of which peaked at 1 h after the injection. Maximum neutrophil infiltration induced by TNF alpha was inhibited by 38-56% by anti-IL-8 IgG, 22-43% by rrIL-1Ra, and 77-83% by anti-IL-8 IgG plus rrIL-1Ra. In contrast, maximum neutrophil infiltration induced by IL-1 beta was not inhibited by anti-IL-8 IgG whereas anti-TNF alpha mAb reduced the infiltration by 68-75%.

CONCLUSIONS

The involvement of IL-8 in TNF alpha- and IL-1 beta-induced neutrophil infiltration is limited. Factor(s) other than IL-8 appear to function as major neutrophil chemo-attractants.

Analysis of the inflammatory cytokine network among TNF alpha, IL-1 beta, IL-1 receptor antagonist, and IL-8 in LPS-induced rabbit arthritis

We investigated the cytokine network in rabbit lipopolysaccharide (LPS)-induced arthritis, using inhibitors against homologous TNF alpha, IL-1 beta, and IL-8. Rabbits were intraarticularly injected with LPS (10 ng) and cytokine inhibitors (10 micrograms each), and the concentrations of each cytokine in the synovial fluids were measured. Maximum levels of TNF alpha and IL-8 were detected at 2 hours after LPS-injection, whereas IL-1 beta and IL-1 receptor antagonist (IL-1Ra) were detected at 6 and 9 hours, respectively. By immunohistochemistry, synovial lining cells were positive for TNF alpha and IL-8, and infiltrating leukocytes were positive for IL-1 beta and IL-1 Ra. The effects of cytokine inhibitors on the release of each cytokine were then investigated. The maximum levels of TNF alpha and IL-8 were not affected by blocking the activities of other cytokines. In contrast, the peak concentration of IL-1 beta was reduced by anti-TNF alpha monoclonal Ab (mAb), IL-1 Ra or anti-IL-8 IgG. Peak concentrations of IL-1Ra were reduced by anti-TNF alpha mAb or anti-IL-8 IgG. Anti-TNF alpha mAb, IL-1Ra, and anti-IL-8 IgG reduced the recruitment of leukocytes into the joint cavity, and the effect of anti-IL-8 IgG was less than that of anti-TNF alpha mAb plus IL-1Ra. The initial phase of the leukocyte influx was not inhibited. These results provide new evidence that IL-8 as well as TNF alpha are the most proximal cytokines and induce subsequent production of IL-1 beta and IL-1Ra. The data also raise the possibility that factor(s) other than IL-8 may be involved in the leukocyte influx in LPS-induced arthritis.

Detection and characterization of IL-1 receptor antagonist in tissues from healthy rabbits: IL-1 receptor antagonist is probably involved in health

Interleukin 1 (IL-1) is postulated to function in maintaining homeostasis, however, over-action of this cytokine may lead to disruption of homeostasis due to it's wide spectrum of activities. To understand the endogenous regulation of this cytokine, we examined the existence of IL-1 receptor antagonist (IL-1Ra) in tissues from healthy rabbits. IL-1Ra was constitutively produced in all tissues examined (lung, liver, spleen, thymus, caecum, skin, kidney, heart, and brain), as estimated by ELISA. Immunoprecipitation, RT-PCR and immunohistochemical studies indicated that all tissues produced secreted form of IL-1Ra (sIL-1Ra), whereas thymus, caecum, skin and kidney produced both sIL-1Ra and intracellular of IL-1Ra. All tissue IL-1Ra purified using anti-IL-1Ra IgG affinity chromatography had inhibitory activity on the IL-1-induced thymocyte proliferative response, and the activity was totally abolished by anti-IL-1Ra mAb. No IL-1 activity was detected in any tissues except skin and heart, however, after preincubation of the samples with anti-IL-1Ra, the activity was first visible in the tissues. Under these conditions, IL-1 activity in skin and heart was enhanced to 170% and 280%, respectively. Taken together, we conclude that tissue IL-1Ra is involved in health maintenance by masking co-existing IL-1 activity present in tissues.

Involvement of tumor necrosis factor-alpha, interleukin-1 beta, interleukin-8, and interleukin-1 receptor antagonist in acute lung injury caused by local Shwartzman reaction

A local Shwartzman reaction (LSR) was prepared in rabbit lung as a model of acute lung injury. To induce LSR, intratracheal injection of lipopolysaccharide (LPS) 10 micrograms into the lower lobe of the right lung, followed 24 h later by i.v. injection of LPS (10 micrograms/kg). In the lung with the LSR, myeloperoxidase activity, representing neutrophil accumulation, peaked at 1-2 h and was sustained for 48 h after challenge with i.v. LPS. The lung water content peaked at 12 h, and decreased gradually. Histological findings showed diffuse interstitial widening, intra-alveolar leukocyte infiltration with hemorrhage, and alveolar exudate formation. The production of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin-8 (IL-8), and IL-1 receptor antagonist (IL-1 Ra) in the lung was analyzed. TNF-alpha first elevated and peaked at 0.5 h (66.5 +/- 16.7 ng/g.lung), subsequently, IL-1 beta and IL-8 increased and peaked at 2 h (17.8 +/- 3.4 ng/g.lung and 336.9 +/- 49.6 ng/g.lung, respectively). IL-1Ra was present even before the challenge, and the production increased to show a dual peak (0.5 h, 1.5 +/- 0.2 micrograms/g.lung; and 2 h, 1.6 +/- 0.1 micrograms/g.lung), and a large concentration of IL-1Ra was sustained for 48 h. Immunohistochemistry showed that the cellular source of these cytokines was alveolar macrophages and infiltrating neutrophils. Thus, disclosing the kinetics of the generation of cytokines led to a better understanding of their roles, namely TNF-alpha as an initiator, IL-1 and IL-8 as amplifier and effector, and IL-1Ra as regulator of the intensity of acute inflammation.

Blocking of TNF-alpha and IL-1 inhibits leukocyte infiltration at early, but not at late stage of S. aureus-induced arthritis and the concomitant cartilage destruction in rabbits

We investigated the involvement of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in the pathogenesis of heat-killed S. aureus-induced arthritis. TNF-alpha and IL-1beta peaked at 2 and 24 hr after the injection, respectively. Leukocyte infiltration within 12 hr of the inflammation was significantly inhibited (80%) by coinjection of anti-TNF-alpha mAb and IL-1 receptor antagonist (IL-1Ra) with S. aureus; however, leukocyte infiltration at 24 hr and thereafter was not inhibited by these agents. The loss of proteoglycan in S. aureus-induced arthritis was also unchanged either by anti-TNF-alpha mAb, IL-1Ra, or their combination. These results indicate that direct participation of TNF-alpha and IL-1 in the pathogenesis of S. aureus-induced arthritis may be limited to the early stage of inflammation and blocking of these cytokines did not result in diminishing the severity of inflammation. Thus, therapeutic approaches with the objective to suppress TNF-alpha and IL-1 may not be effective in the clinical treatment of gram-positive bacteria-induced arthritis.

[Preclinical and clinical studies on the efficacy of bifonazole in patients with tinea pedis at 10 years after approval. Part 1. Susceptibility to bifonazole of clinical isolates of dermatophytes]

An investigation was carried out to determine whether or not here had been any changes in the susceptibility of clinically isolated strains of Trichophyton metagrophytes and Trichophyton rubrum (both leading causes of tinea) to bifonazole, an imidazole derivative and antifungal for topical use. Susceptibility was measured in 107 strains of these fungi isolated from clinical samples during a study on the treatment of tinea pedis with Mycospor cream in 1995, 42 strains isolated and stored in 1990, and 39 strains isolated and stored prior to development of the drug. The results are as follows: (1) There was no distinct difference in the susceptibility to bifonazole of T. mentagrophytes strains isolated before 1986 and those isolated in 1990 or 1995. (2) T. rubrum strains isolated before 1986 were slightly more susceptible to bifonazole than those isolated in 1995, while the 1990 strains were slightly less susceptible than the 1995 strains, but the difference was not significant. (3) The highest MICs of bifonazole for all the T. mentagrophytes and T. rubrum strains isolated from before 1986 and those in 1995 were relatively low, being 2.5 micrograms/ml and 1.25 micrograms/ml, respectively. These results suggest that no resistance or reduced susceptibility to bifonazole has emerged among clinical isolates of dermatophytes since the development of the drug.

[Fundamental and clinical studies on the efficacy of bifonazole in patients with tinea pedis at 10 years after approval. Part 2. Clinical evaluation]

The usefulness of bifonazole (Mycospor), a topical imidazole antifungal agent approved 10 years ago, was evaluated for the treatment of tinea pedis. Mycospor cream was applied by 141 patients with tinea pedis once daily for 4 233ks, and the clinical efficacy and adverse reactions (as well as any correlations with susceptibility of isolates and the mycological activity of the agent against these isolates) were studied. The results were then compared to those of a previous study. The following results were obtained. 1. Mycological activity Mycological examination results became negative in 63.2% (36/57) of the patients with plantar tinea pedis, in 94.1% (32/34) of those with interdigital tinea pedis, and in 74.7% (68/91) of all tinea pedis patients. 2. Mycological activity and MIC No correlation was found between the MICs of bifonazole against the pathogenic fungi and the rate of eradication on mycological examination. 3. Improvement of symptoms The improvement rates for local symptoms were 82.5% for plantar tinea pedis, 85.7% for interdigital tinea pedis, and 83.7% for all tinea pedis. 4. Clinical efficacy Good clinical efficacies were found in 61.4% of the patients with plantar tinea pedis, in 88.6% of those with interdigital tinea pedis, and in 71.7% of all patients. 5. Safety Regarding adverse reactions, what seemed to be contact dermatitis was reported in 5 out of 127 cases (3.9%). The reaction decreased or disappeared in all cases. 6. Usefulness Mycospor was found to be useful in 64.9% of patients with plantar tinea pedis, in 88.6% of those with interdigital tinea pedis, and in 73.9% of all tinea pedis patients. 7. Comparison with former results The results obtained in the present clinical study were comparable to those obtained in patients with tinea pedis treated in a double-blind comparative study conducted during the development of as a new topical antifungal agent. From the above results, Mycospor cream was confirmed to be still useful, although it has been used widely for the topical treatment of cutaneous mycoses in the past 10 years since its approval.

Interleukin-1 receptor antagonist: characterisation of its gene expression in rabbit tissues and large-scale expression in eucaryotic cells using a baculovirus expression system

The gene expression of rabbit interleukin-1 receptor antagonist (RbIL-lra) was examined in rabbit tissues. RNA was isolated from heart, lung, kidney, muscle, liver, spleen, brain, and peripheral blood monocytes (PBMs), and RbIL-lra mRNA was identified as a single species by Northern analysis using a RbIL-lra probe. RbIL-lra was abundantly expressed in lung, brain, heart, and liver, expressed at low levels in spleen, and undetectable in kidney and unstimulated PBMs. Expression of large scale recombinant production of RbIL-lra was achieved by subcloning the cDNA into a baculovirus expression vector. Recombination of this vector was completed with the BacPAK6 baculovirus genome. The recombinant virus, containing the RbIL-lra cDNA, was used to infect Spodoptera frugiperda (Sf21) insect cells in a spinner flask system and in monolayers in cell culture flasks. Recombinant rabbit IL-lra (rRbIL-lra) was secreted into the culture medium in this system at very high levels (35 mg/l). The protein was identified by reducing SDS-PAGE electrophoresis, was variably glycosylated and had a molecular weight between 19-25 kDa. It was then purified by size exclusion HPLC on a Du Pont Gf-250 column. The rRbIL-lra was demonstrated to be functionally active by inhibiting recombinant human IL-1 alpha in a mouse thymocyte proliferation assay. 20 ng/ml (6.7 U/ml) of rRbIL-lra inhibited 95% of the activity of 2 ng/ml IL-1 alpha.