bluuebunny/crossref_metadata_2025 huggingface dataset:
Arachidonic acid and calcium metabolism in rnelittin stimulated neutrophils
Authors: Nielsen Ole H. , Bouchelouche Pierre N. , Berild Dag
Published: March 2007

Melittin, the predominant fraction of bee venom proteins, was studied in an experimental model of human neutrophil granulocytes to reveal its influence on eicosanoid release, metabolism and receptor function in relation to intracellular calcium metabolism. Melittin (2 μmol/l) was as potent as the calcium ionophore A23187 (10 μmol/l) for activation of 5‐lipoxygenase, releasing arachidonate only from phosphatidyl‐choline and phosphatidyl‐ethanolamine of cellular membranes, as judged from the decreases in radioactivity by 15.4% and 30.5%, respectively. The mechanism responsible for the release of arachidonate from cellular membranes is closely coupled to cellular calcium metabolism, and melittin was found to promote calcium entry through receptor gated calcium channels, probably due to an activation of phospholipase A2. Furthermore, a down‐regulation of leukotriene B4 receptors was seen. The maximal number of binding sites per cell was reduced from a median of 1520 to 950 with melittin (1 μmol/l). The study has revealed some factors important for the inflammatory mechanisms mediated by melittin.
Suppressive effect of TNF‐α and IL‐1 on alveolar fibroblast proliferation in sarcoidosis
Authors: Fireman E. , Aderka D. , Efraim S. Ben , Greif J. , Wallach D. , Topilsky M.
Published: March 2007

The nature of soluble factors that regulate fibroblast proliferation have not been finally characterized. Our aim was to study the role of tumour necrosis factor α (TNF‐α) and interleukin‐1 (IL‐1) in the suppressive activity of alveolar macrophages on autologous lung fibroblasts proliferation in sarcoidosis. We found that supernatants recovered from alveolar macrophages suppressed the proliferation of alveolar fibroblast in sarcoidosis by 35.5 ± 1.13% compared to 3 ± 16% in controls (p < 0.001 between the two groups). This suppression correlated with high content of TNF‐α and IL‐1 in sarcoidosis patients stage II‐III (7.7 ± 2.9 ng/ml TNF‐α and 157 ± 53 U/ml IL‐1 compared to 3.4 ± 2.4 ng/ml TNF‐α and 43 U/ml IL‐1 in controls; p < 0.01 and p < 0.001, respectively). Both cytokines in sarcoidosis stage I were within the normal ranges. Exogenous TNF‐α (1000‐0.5 ng/ml) and IL‐1 (500‐0.24 ng/ml) had an additive suppressive activity on fibroblast proliferation which was partially reversed by indomethacin.
Free circulating ICAM‐1 in serum and cerebrospinal fluid of HIV‐1 infected patients correlate with TNF‐α and blood‐brain barrier damage
Authors: Sharief M. K. , Ciardi M. , Noori M. A. , Thompson E. J. , Salotti A. , Sorice F. , Rossi F. , Cirelli A.
Published: March 2007

The mechanism for the initiation of blood‐brain barrier damage and intrathecal inflammation in patients infected with the human immunodeficiency virus (HIV) is poorly understood. We have recently reported that tumour necrosis factor‐α (TNF‐α) mediates active neural inflammation and blood‐brain barrier damage in HIV‐1 infection. Stimulation of endothelial cells by TNF‐α induces the expression of intercellular adhesion molecule‐1 (ICAM‐1), which is an important early marker of immune activation and response. We report herein for the first time the detection of high levels of free circulating ICAM‐1 in serum and cerebrospinal fluid of patients with HIV‐1 infection. Free circulating ICAM‐1 in these patients correlated with TNF‐α concentrations and with the degree of blood‐brain barrier damage and were detected predominantly in patients with neurologic involvement. These findings have important implications for the understanding and investigation of the intrathecal inflammatory response in HIV‐1 infection.
IL‐1β and IL‐6 modulate apolipoprotein E gene expression in rat hepatocyte primary culture
Authors: Ribeiro Agnes , Mangeney Marise , Bernard Isabelle , Chambaz Jean , Delers Francisco
Published: March 2007

Incubation of rat hepatocytes in primary culture with IL‐1β at a concentration of 2.5 units/ml resulted in an increase (+80%) in the amount of apoE mRNA without any effect upon apoE synthesis. IL‐6 at a low concentration (10 units/ml) induced a decrease (−35%) in the amount of apoE mRNA, but increased apoE synthesis (+28%). No effect was observed with higher concentrations of IL‐1β (10 units/ml) or IL‐6 (100 units/ml). These results suggest that inflammatory cytokines IL‐1β and IL‐6 modulate the expression of apoE gene in cultured rat hepatocytes, at a concentration that does not induce the acute phase response.
Leukotriene inhibition in hamster periodontitis. A histochemical and morphometric study
Authors: Baroukh B. , Saffar J. L.
Published: March 2007

The effects of leukotriene (LT) inhibition on gingival and adjacent bone compartments were assessed by using phenidone (100 mg/kg/d) and ketoconazole (50 mg/kg/d) given for 4 weeks to periodontitis‐affected hamsters. In the gingiva the two agents significantly decreased PMNL recruitment and migration and increased the vascular lumen. At the bone level, they reduced significantly preosteoclast and osteoclast numbers but did not affect osteoclast activity. Phenidone had no action on periodontitis induced inhibition of bone formation; in contrast ketoconazole enhanced formation. As both phenidone and ketoconazole are unspecific LT inhibitors it cannot be ascertained that the effects observed were actually due to LT inhibition. However, phenidone and ketoconazole induced changes different from indomethacin used in previous studies to inhibit the cyclooxygenase pathway. These discrepancies suggest that LT inhibition occurred in the present study and that they participate in gingival inflammation and osteoclastic destruction during hamster periodontitis.
Blood levels of PAF are elevated during induction of immune complex mediated enteropathy in the rat
Authors: Bloch K. J. , Ng B. P. , Bloch M.
Published: March 2007

Intravenous injection into rats of immune complexes (IC) prepared in 5 × antigen excess rapidly induces annular bands of vascular congestion and transmural haemorrhage producing a striped appearance of the small intestine. Indirect evidence suggested a major role for PAF in the induction of lesions. In the present study, we showed that blood and leukocyte levels of PAF were elevated in most rats injected 10 min earlier with sufficient IC to induce lesions of 3+ to 4+ intensity. There was no significant difference in the number of rats with elevated plasma levels of PAF. The possibility that changes in blood PAF levels might be mirrored at sites closer to the lesions was considered. The overall effect of PAF on the small intestine of the rats is to induce stasis of flow; the precise target of PAF in mediating this effect is unknown.
Role of interleukin‐1 and tumour necrosis factor in leukocyte recruitment to acute dermal inflammation
Authors: Issekutz Andrew C. , Lopes Nancy , Issekutz Thomas B.
Published: March 2007

The cytokines IL‐1 and TNF‐α are involved in inflammation and their production is stimulated by various agents, especially endotoxin (LPS). Here, using the human IL‐1 receptor antagonist (IL‐1RA) and a new monoclonal antibody (mAb 7F11) to rabbit TNF, the role of endogenous IL‐l and TNF production in acute (3h) leukocyte (PMNL) recruitment to dermal inflammation in rabbits has been studied. IL‐1RA inhibited by 27% the PMNL accumulation in reactions induced by killed Escherichia coli (p < 0.05) but not by LPS. The monoclonal antibody to TNF inhibited by 27% and 38% (p < 0.002) the PMNL accumulation in LPS and E. coli reactions respectively, but a combination of the mAb with IL‐1RA was not more effective. Treatment of human umbilical vein endothelium with LPS for 3 h activated endothelium to induce PMNL transendothelial migration in vitro, which was not inhibited by IL‐1RA, antibody to TNF‐α, IL‐1 or to IL‐8. In conclusion, TNF and IL‐1 may partially mediate acute PMNL infiltration in vivo to LPS and Gram negative bacteria, but there is a major IL‐1/TNF independent mechanism, at least in dermal inflammation, which may be due to direct LPS activation of the microvasculature or perhaps the generation of cytokines other than IL‐1 and TNF.
Reactive oxygen species induced structural alterations of substance P
Authors: Konttinen Y. T. , Kemppinen P. , Segerberg M. , Sorsa T. , Saari H. , Hukkanen M.
Published: March 2007

Substance P (SP1‐11) was exposed to a continuous flux of superoxide () or hydroxyl radicals (.OH) in a hypoxanthine (HX)/xanthine oxidase (86 mU) system in the presence of 1 mM deferoxamine and 40 mM D‐mannitol or 50 μM FeCI3. 6H2O and 50 μM EDTA, respectively. caused fragmentation between the Phe7 and Phe8, whereas .OH induced cleavage also between the Phe8 and Gly9. Reactive oxygen species H2O2 and HCIO did not cause fragmentation, but modification of the amino acid side chains and/or aggregation with altered hydrophobicity in reverse phase high performance liquid chromatography compared to native SP1‐11. Furthermore, exposure of SP1‐11 to phorbol myristate acetate preactivated neutrophils resuited in products similar to those observed upon exposure to superoxide or hydroxyl radicals in a cell‐free HX/xanthine oxidase system. This study suggests that, in contrast to rigid proteins, fragmentation is relatively easily induced in a small peptide like SP1‐11, perhaps due to strain on the peptide and t‐carbon bonds caused by the movable, random coil configuration acquired by SP1‐11 in an aqueous solution. Oxidative modification might modulate paracrine actions of SP1‐11 at site of inflammation.
Is platelet activating factor (PAF) an important mediator in bronchial asthma?
Authors: Gundel R. H. , Heuer H. O. , Letts L. G.
Published: March 2007

The development of selective PAF receptor antagonists may provide a novel approach to the treatment of human bronchial asthma. In preclinical animal models of human asthma, PAF receptor antagonists have been found to be efficacious in blocking antigen‐induced changes in lung function. However, the majority of these models involve acute inflammatory events and transient changes in lung function and, therefore, their relevance to human asthma is questionable. In a recent study with a primate model of chronic airway inflammation and hyperresponsiveness, we have shown that treatment with a PAF receptor antagonist had no effect on reducing chronic inflammation and hyperresponsiveness. Similarly, recent studies in human asthmatics with PAF receptor antagonists have failed to show efficacy in blocking allergen‐induced airway responses or to have any steroid sparing effects in patients with ongoing asthma. Thus, it seems that PAF may not be a key mediator which can be blocked and thereby provide therapy for bronchial asthma.
Study on the pathogenesis of pathophysiological changes of burn systemic infection
Authors: Ao (Ngao) Li , Yuesheng Huang , Zongcheng Yang
Published: March 2007

The present prospective study showed that incidence of systemic infection in severe burn patients was 30.9%. Toxic shock and multiple organ failure (MOF) developed in all patients with uncontrolled systemic infection. Both morbidity and mortality of MOF were 76.5%. In the infection group, plasma TXB2 and TXB2/6‐keto‐PGF1α ratio increased markedly. Their changes were closely correlated with the clinical course and deterioration of systemic infection. Circulatory platelet aggregate ratio decreased significantly, while myocardiac enzyme spectrum greatly increased. Thrombi were observed in visceral tissues from patients dying of systemic infection. These suggested that TXA2/PGI2. imbalance promoting microaggregate and thrombus formation may be one of the pathogenic effects of toxic shock and MOF in burn patients.
Effects of esculentoside A on turnour necrosis factor production by mice peritoneal macrophages
Authors: Jun Fang , Yue Zheng Qin , Bin Wang Hong , Wen Ju Dian , Hua Yi Yang
Published: March 2007

Esculentoside A (EsA) is a saponin isolated from the roots of Phytolacca esculenta. Previous experiments showed that it had strong anti‐inflammatory effects. Tumour necrosis factor (TNF) is an important inflammatory mediator. In order to study the mechanism of the anti‐inflammatory effect of EsA, it was determined whether TNF production from macrophages was altered by EsA under lipopolysaccharide (LPS) stimulated conditions. EsA was found to decrease both extracellular and cell associated TNF production in a dose dependent manner at concentrations higher than 1 μmol/l EsA. Previous studies have showed that EsA reduced the releasing of platelet activating factor (PAF) from rat macrophages. The reducing effects of EsA on the release of TNF and PAF may explain its anti‐inflammatory effect.
A PAF receptor antagonist inhibits acute airway inflammation and late‐phase responses but not chronic airway inflammation and hyperresponsiveness in a primate model of asthma
Authors: Gundel R. H. , Wegner C. D. , Heuer H. O. , Letts L. G.
Published: March 2007

We have examined the effects of a PAF receptor antagonist, WEB 2170, on several indices of acute and chronic airway inflammation and associated changes in lung function in a primate model of allergic asthma. A single oral administration WEB 2170 provided dose related inhibition of the release of leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) recovered and quantified in bronchoalveolar lavage (BAL) fluid obtained during the acute phase response to inhaled antigen. In addition, oral WEB 2170 treatment in dual responder primates blocked the acute influx of neutrophils into the airways as well as the associated late‐phase airway obstruction occurring 6 h after antigen inhalation. In contrast, a multiple dosing regime with WEB 2170 (once a day for 7 consecutive days) failed to reduce the chronic airway inflammation (eosinophilic) and associated airway hyperresponsiveness to inhaled methacholine that is characteristic of dual responder monkeys. Thus, we conclude that the generation of PAF following antigen inhalation contributes to the development of lipid mediators, acute airway inflammation and associated late‐phase airway obstruction in dual responder primates; however, PAF does not play a significant role in the maintenance of chronic airway inflammation and associated airway hyperresponsiveness in this primate model.
Human keratinocyte sensitivity towards inflammatory cytokines varies with culture time
Authors: Elliott G. , Meent D. van de , Dijk J. van , Mol M.
Published: March 2007

Proliferating keratinocyte cultures have been reported to synthesize higher concentrations of prostaglandin (PG) E than confluent ones. As interleukin‐1 (IL‐1) stimulates keratinocyte PGE synthesis we investigated whether the degree of confluency of the keratinocyte culture modified the response of the cells to IL‐1. It was found that IL‐1α (100 U/ml) stimulated PGE2 synthesis by proliferating (7 days in culture) but not differentiating (14 days in culture) keratinocytes. Similar effects were observed using tumour necrosis factor‐α. Both arachidonic acid (AA) and the calcium ionophore A23187 stimulated PGE2 synthesis by 7 and 14 day cultures although the increase was greatest when 7 day cultures were used. Our data indicate that there is a specific down‐regulation of the mechanism(s) by which some inflammatory cytokines stimulate keratinocyte eicosanoid synthesis as cultured keratinocytes begin to differentiate.
Tumour necrosis factor‐alpha and interleukin‐8 inhibit neutrophil migration in vitro and in vivo
Authors: Cunha F. Q. , Tamashiro W. M. S. Cunha
Published: March 2007

Pretreatment of human neutrophils with recombinant tumour necrosis factor‐alpha (rTNF‐α) and/or interleukin‐8 (rIL‐8), but not with either transforming growth factor‐beta, interleukin‐6 or interferon‐gamma, rendered these cells less responsive to FMLP, in microchemotaxis assays. This inhibitory effect was dose dependent and more powerful when neutrophils were pretreated with a mixture of both cytokines. Intravenous injection of human rIL‐8 (hrIL‐8) and/or murine rTNF‐α (mrTNF‐α) also significantly reduced in vivo neutrophil migration into peritoneal cavities of rats stimulated with carrageenan. These data suggest that the defect in neutrophil migration during septicaemia or endotoxaemia may be the result of the continuous release of IL‐8 and TNF‐α into the circulation. Thus, either the selective control or blockade of releasing of these cytokines as well as of its effects on neutrophils may be clinically useful in reestablishing the cell defence mechanisms.
Five steps in leukocyte extravasation in the microcirculation by chemoattractants
Authors: Oda T. , Katori M. , Hatanaka K. , Yamashina S.
Published: March 2007

For in vivo study of the phenomena observed in vitro, PMN (polymorphonuclear leukocyte) extravasation was analysed quantitatively in the microcirculation of the hamster cheek pouch using a video system. Topical application of leukotriene B4 or N‐formyl‐methionylleucyl‐ phenylalanine increased dose dependently the number of PMNs adhering to the venules. Eighty to 90% of the adhering PMNs disappeared from the vascular lumen into the venular wall within 10‐12 rain after the adhesion. After PMNs had passed through the endothelial cell layer, they remained in the venular wall for more than 30 min after application of the chemoattractants and appeared in the extravascular space. Thus, the process could be divided into five steps: (1) rolling and (2) adhesion to the endothelium, (3) passage through the endothelial layer (4) remaining in the venular wall, and (5) passage through the basement membrane.
Differential regulation of TNF‐α and IL‐1β production from endotoxin stimulated human monocytes by phosphodiesterase inhibitors
Authors: Molnar-Kimber K. L. , Yonno L. , Heaslip R. J. , Weichman B. M.
Published: March 2007

The effect of selective PDE‐I (vinpocetine), PDE‐III (milrinone, CI‐930), PDE‐IV (rolipram, nitroquazone), and PDE‐V (zaprinast) isozyme inhibitors on TNF‐α and IL‐1β production from LPS stimulated human monocytes was investigated. The PDE‐IV inhibitors caused a concentration dependent inhibition of TNF‐α production, but only partially inhibited IL‐1β at high concentrations. High concentrations of the PDE‐III inhibitors weakly inhibited TNF‐α, but had no effect on IL‐1β production. PDE‐V inhibition was associated with an augmentation of cytokine secretion. Studies with combinations of PDE isozyme inhibitors indicated that PDE‐III and PDE‐V inhibitors modulate rolipram′s suppression of TNF production in an additive manner. These data confirm that TNF‐α and IL‐1β production from LPS stimulated human monocytes are differentially regulated, and suggest that PDE‐IV inhibitors have the potential to suppress TNF levels in man.
Elevated plasma levels of endothelin are associated with the severity of sepsis and presence of shock in contrast to the levels of atrial natriuretic peptide
Authors: Beishuizen A. , Götz J. M. , Kip L. , Haanen C. , Vermes I.
Published: March 2007

Immunoreactive endothelin (ETi) and atrial natriuretic peptide (ANPi) blood levels were measured by radioimmunoassay in patients with clinically defined sepsis. The interaction between these two peptides and their relation to circulatory shock and mortality were studied. All septic patients (n = 16) had significantly higher ETi (22.3 ± 11.1 pg/ml) and ANPi (398.3 ± 154.3 pg/ml) plasma concentrations compared to control subjects (ETi, 4.1 ± 1.2; ANPi, 59.1 ± 14.8 pg/ml; n = 13). ETi levels followed the severity of illness according to the APACHE II scoring system and were higher in patients who did not survive. ETi levels were significantly higher in the presence of shock and bacteraemia. Furthermore, ETi correlated well with plasma lactate (r = 0.83, p < 0.05), but not with renal function. ANPi levels did not show correlation with any of these determinants. Serial blood sampling, six consecutive days after admission, showed that ETi levels gradually decreased in normotensive patients in contrast to patients with septic shock. ANPi levels did not show systematic changes in time, and no relationship was observed between ETi and ANPi levels. These results suggest that plasma ETi levels are indicative for disease severity and might have prognostic significance. The role of ANPi during sepsis remains to be eludicated.
Biological significance of soluble IL‐2 receptor
Authors: Caruso Calogero , Candore Giuseppina , Cigna Diego , Colucci Antonio Tobia , Modica Maria Assunta
Published: March 2007

A NUMBER of receptors for growth factors and differentiation antigens have been found to be secreted or released by cells. Following mononuclear cell (MNC) activation and interleukin‐2 receptor (IL‐2R) expression, a soluble form of the Alpha;‐chain of IL‐2R (sIL‐2R) is released. The sIL‐2R has been shown to be present in the culture supernatants of activated MNCs as well as in normal sera and, in higher amounts, in sera from subjects affected by several diseases including neoplastic, infectious and autoimmune ones, and in sera from transplanted patients suffering allograft rejection. The blood sIL‐2R levels depend on the number of producing cells and the number of molecules per cell, so that sIL‐2R blood values may represent an index of the number and the functional state of producing cells, both normal and neoplastic. Thus, monitoring of the immune system, mostly T‐cells and haematological malignancies might be targets for the measurement of sIL‐2R. Since many conditions may influence sIL‐2R production, little diagnostic use may result from these measurements. However, since blood sIL‐2R levels may correlate with disease progression and/or response to therapy, their measurement may be a useful index of activity and extent of disease. The precise biological role of the soluble form of the IL‐2R is still a matter of debate. However, we know that increased sIL‐2R levels may be observed in association with several immunological abnormalities and that sIL‐2R is able to bind IL‐2. It is conceivable then that in these conditions the excess sIL‐2R released in vivo by activated lymphoid cells or by neoplastic cells may somehow regulate IL‐2‐dependent processes. On the other hand, it cannot exclude that sIL‐2R is a by‐product without biological significance. Finally, it is puzzling that in many conditions in which an increase of blood sIL‐2R values has been observed, MNCs display a decreased in vitro capacity to produce sIL‐2R. These seemingly contrasting findings are discussed in the light of the data showing that sIL‐2R production correlates with IL‐2 production.
Compartmentalization of TNF and IL‐6 in meningitis and septic shock
Authors: Waage Anders , Halstensen Alfred , Espevik Terje , Brandtzæg Petter
Published: March 2007

We examined the compartmentalization of bioactive tumour necrosis factor (TNF) and interleukin 6 (IL‐6) to the subarachnoid space and systemic circulation in patients with meningococcal meningitis and septic shock/bacteraemia. In patients with meningitis, median levels of TNF in 31 paired samples of cerebrospinal fluid (CSF) and serum were respectively 783 pg/ml and below detection limit (p < 0.001) and median levels of IL‐6 were 150 ng/ml and 0.3 ng/ml (p < 0.0001). In patients with septic shock without meningitis, median levels in paired samples of CSF and serum were respectively below detection limit and 65 pg/ml (not significant, (ns)) (TNF, eleven patients) and 1.3 ng/ml–3 ng/ml (ns) (IL‐6, nine patients). The data show that TNF and IL‐6 are localized to the subarachnoid space in patients with meningitis although the blood–brain barrier is penetrable to serum proteins. On the other hand, patients with septic shock tend to have cytokines in both serum and CSF.
IL‐1 and its role in rat carrageenan pleurisy
Authors: Goodman R. , Mantegna L. R. , McAIlister C. L. , Bruin E. , Dowling R. L. , George H. , Feeser W. , Freimark B. , Lischwe M. , Pick S. , Harris R. R. , Kerr J. S.
Published: March 2007

The carrageenan pleurisy model, which is characterized by cellular influx and oedema, has been used to examine the effects of anti‐inflammatory compounds such as naproxen. Interleukin‐1α and β (IL‐1) are known to be pro‐inflammatory mediators, and their roles in this model are unknown. Intrapleural injection of 1% viscarin carrageenan or saline was administered to male Lewis rats. Four to 24 h later, cell counts, fluid volumes and IL‐1β levels (measured by ELISA) were determined in the pleural cavity. Serum corticosterone levels were measured only at 4 h. Significant increases in IL‐1β levels precede cell influx suggesting IL‐1β plays a role in the maintenance of cell accumulation in the pleural cavity. None of the drugs tested, including the IL‐1 receptor antagonist, maintained pleural cell influx and IL‐1β levels at control levels. When human IL‐1α or β or rat IL‐1β were injected individually into the pleural cavity, none of these cytokines were pro‐inflammatory, as measured by increased cell influx and fluid extravasation. These results suggest that although IL‐1β levels increase in the pleural cavity in response to carrageenan, IL‐1 per se is not the initiator of the pro‐inflammatory events of cell influx and oedema in this model.
Lack of involvement of lipocortin 1 in dexamethasone suppression of IL‐1 release
Authors: Morand E. F. , Rickard D. , Goulding N. J.
Published: March 2007

The annexin lipocortin 1 is reported to mediate some anti‐inflammatory effects of glucocorticoids, but the mechanisms of this mediation are incompletely understood. The involvement of lipocortin 1 in glucocorticoid inhibition of monocyte interleukin 1β (IL‐1β) release has been investigated. Treatment of peripheral blood monocytes with 2 μg/ml lipopolysaccharide potently increased IL–1β release (p = 0.001) and dexamethasone (10−7 M) significantly reduced both resting and stimulated IL‐1β release (p = 0.009). A neutralizing monoclonal antibody to lipocortin 1 (0.5–50.0 μg/ml) was unable to inhibit this effect and recombinant lipocortin 1 (2 × 10−6 M) and 188aa lipocortin 1 fragment (10−8−10−6 M) had no effect. It is concluded that lipocortin 1 is not involved in the inhibition of monocyte IL‐1β release by glucocorticoids.
Production of oxygen free radicals by Ehrlich ascites tumour cells: effect of lipids
Authors: Marathe Gopal K. , D′Souza Cletus J. M.
Published: March 2007

Phorbol‐12‐myristate‐13‐acetate (PMA), calcium ionophore A23187 and platelet activating factor (PAF) stimulated the generation of oxygen free radicals (nitro‐blue tetrazolium reduction) in Ehrlich ascites tumour (EAT) cells. PAF was effective at an optimal concentration of 4 μM, but was inhibited by BN 52021, a specific PAF antagonist. Lyso‐PAF was ineffective. Inclusion of different lipids during incubation prior to the addition of PAF, resulted in the activation/inhibition of free radical generation. Among the phospholipids at a concentration of 50 μg/ml, the order of activation was phosphatidylserine > phosphatidylglycerol > phosphoinositides > phosphatidylinositol > phosphatidylethanolamine. Phosphatidylcholine was not effective, while sphingolipids were inhibitory. In addition, Ehrlich ascites tumour cells grown in mice under marginal vitamin A deficiency, showed an augmented production of free radicals compared to control cells. This was suppressed by exogenous addition of vitamin A or superoxide dismutase. These results suggest that membrane lipids and dietary factors like vitamin A probably function as physiological modulators in regulating the free radical generation.
The effect of malotilate, a derivative of malotilate and a flavenoid on eicosanoid production in inflammatory bowel disease in rats
Authors: Dijk A. P. M. van , Wilson J. H. P. , Zijlstra F. J.
Published: March 2007

Acetic acid induced colitis in rats was used to investigate the effects of malotilate, a drug which has been shown to inhibit 5‐1ipoxygenase in human macrophages, the malotilate derivate ZY16268 and the flavenoid ZY16369 on the eicosanoid production and the colonic morphology in inflammatory bowel disease. Acetic acid produced an acute inflammatory response in the colon, associated with a markedly raised inflammation score (15.8 vs. < 0.5), based on a seven‐scaled scoring system which includes observation of haemorrhage, submucosal oedema, cellular infiltration, goblet cell depletion, loss of architecture, crypt abscesses and serosal involvement, of which every item was subdivided as mild, moderate and severe. Incubation of colonic mucosa from rats treated with arachidonic acid and stimulated with A23187 showed an increase of the cyclooxygenase product 12‐hydroxy‐heptadecatrienoic acid (HHT) and the 12‐1ipoxygenase product (12‐HETE) and a decrease in the formation of 6‐keto‐prostaglandin F1α(6kPGF1α) in comparison with normal rat mucosa. Malotilate, ZY16268 and ZY16369 all resulted in a decrease in HHT, leukotriene B4 (LTB4)‐like compounds and 12‐hydroxyeicosaenoic acid (12‐HETE) production. None of the tested compounds significantly reduced the colonic damage by acetic acid although the formation of 12‐HETE was proportional to the histologically obtained inflammation score. There were marked differences in eicosanoid formation patterns between rat and human mucosa, both normal and inflamed. In view of the hyperacute nature of the mucosal damage and the marked differences in eicosanoid production, acetic acid induced colitis in rats is probably not a suitable model of ulcerative colitis in humans.
Cytokine and eicosanoid regulation by Schistosoma mansoniduring LSE penetration
Authors: Fusco A. C. , Salafsky B. , Shibuya T.
Published: March 2007

Cercarial penetration, in low to moderate numbers, does not cause a normal skin inflammatory response; therefore, the authors sought to determine whether cercariae can down‐regulate keratinocyte activation and thus the secretion of pro‐inflammatory cytokines and eicosanoids. Human living skin equivalent (LSE, Organogenesis) consisting of dermal, epidermal and stratum corneum‐like layers was used as the skin substrate. The surface of the LSE membrane was exposed to 100 ng IFNγ or ~850 cercariae for 18 h. Incubation media and tissue was then assayed for IL‐1α, IL‐6, IL‐8, TNFα, 5‐HETE, 12‐HETE, PGF2, LTB4, and LTC4 via RIA and Western Blots. TNFα was not detected. Secreted IL‐1α levels were (mean ± S.E.M. (n)): Control, 1.03 ng ± 0.15 (11); IFNγ 1.90 ng ± 0.48 (5); cercariae, 1.79 ng ± 0.22 (22). In spite of this increase, cercariae down‐regulated IL‐8 (cercariae 11.13 ± 1.70 ng vs. IFNγ = 16.47 ± 0.29 ng, p = 0.04) and LTB4 (cercariae = 98.86 ± 19.65 pg/0.1 ml vs. IFNγ = 193.42 ± 44.21 pg/0.1 ml p = 0.02). No changes were seen in IL‐6, 12‐HETE, 5‐HETE, and PGE2 levels. It is concluded that cercarial penetration causes a release of IL‐1α consistent with skin trauma; however, schistosomulae may regulate the production of chemotactic (neutrophils, macrophages, T‐cells, etc.) and activation factors such as IL‐8 and LTB4.
Phospholipid derived mediators and glomerulonephritis
Authors: Wardle E. N.
Published: March 2007

The contributions made by the various eicosanoids, PAF, the HETES and the lipoxins to the pathophysiology of glomerulonephritis is reviewed. A case can be made for clinical trials of PAF, leukotriene and thromboxane antagonists. Combined thromboxane synthetase and thromboxane receptor antagonism would seem to be the more efficacious approach for the various disease entities.
Inhibition of smooth muscle contraction and platelet aggregation by peptide 204–212 of lipocortin 5: an attempt to define some structure requirements
Authors: Mugridge K. G. , Becherucci C. , Parente L. , Perretti M.
Published: March 2007

Peptide 204–212 of lipocortin (LC) 5 inhibited porcine pancreatic phospholipase A2 (PLA2) induced rat stomach strip contractions and ADP induced rabbit platelet aggregation in a concentration dependent manner (IC30 of 10 μM and 400 μM, respectively). The first two amino acids are not necessary since the eptapeptide 206–212 was equipotent in both assays (IC30 of 12.5 μM and 420 μM). Of the two pentapeptides 204–208 and 208–212 only the latter showed inhibitory activity in both models although the potency was much reduced (IC30 of 170 μM and 630 μM) compared with that of the parent nonapeptide. Comparison of peptide 204–212 effects with those of its analogues on LC1 and LC2 indicate that lysine 208 and aspartic acid 211 are essential in order to maintain a fully active nonapeptide.
Conceivable difference in the anti‐inflammatory mechanisms of lipocortins 1 and 5
Authors: Becherucci C. , Perretti M. , Solito E. , Galeotti C. L. , Parente L.
Published: March 2007

Human recombinant lipocortins (LCT) 1 and 5 have been expressed in a yeast secretion vector and purified by ion exchange chromatography. The action of the proteins has been investigated in two models of experimental acute inflammation in the rat: carrageenin induced paw oedema and zymosan induced pleurisy. The effects of the proteins on PGE2 release in vitro by rat macrophages stimulated with zymosan and on rat neutrophil chemotaxis induced by FMLP have also been assessed. LCT‐1 significantly inhibited both paw swelling in carrageenin oedema and leukocyte migration in zymosan pleurisy. Moreover it showed a dose dependent, inhibitory effect on PGE2 release. Neutrophil chemotaxis was only weakly affected by LCT‐1. Conversely LCT‐5 did not reduce carrageenin oedema and slightly inhibited PGE2 release, but showed profound, dose dependent inhibitory activity on leukocyte migration in zymosan pleurisy and on neutrophil chemotaxis. These data suggest that LCT‐1 acts mainly by interfering with arachidonic acid metabolism via the inhibition of phospholipase A2. The anti‐inflammatory activity of LCT‐5, at variance with LCT‐1, may be due to a direct effect on cell motility in addition to the interference with arachidonic acid metabolism.
Effects of acute cigarette smoke exposure on macrophage kinetics and release of tumour necrosis factor α in rats
Authors: Pessina G. P. , Paulesu L. , Corradeschi F. , Luzzi E. , Stefano A. Di , Tanzini M. , Matteucci G. , Bocci V.
Published: March 2007

Some biological parameters before and after an acute episode of cigarette smoking in rats have been evaluated. The carboxyhaemoglobin levels depended either on the number of cigarettes, or on the time of exposure to cigarette smoke and returned to pre‐smoking values in about 2 h. The evaluation of the kinetics of alveolar and peritoneal macrophages in rats after a smoking session of three cigarettes within an hour, indicated that alveolar macrophages in the bronchoalveolar lavage fluid significantly increased 8 h after the smoking, whereas the number of peritoneal macrophages remained practically constant. The incubation of these cells for various times at 37°C in a humidified atmosphere, resulted in a spontaneous release, 24 h thereafter, of variable amounts of tumour necrosis factor α (TNFα), which remained practically constant during the following days. Neither alveolar macrophages of control rats, nor peritoneal macrophages of both control and smoking rats were able to release TNFα. Moreover, after lipopolysaccharide induction of alveolar macrophages of both control and smoking rats, an increased release of TNFα was observed, indicating that these cells were in an active state.
Transient sex‐related changes in the mice hypothalamo–pituitary–adrenal (HPA) axis during the acute phase of the inflammatory process
Authors: Daneva T. , Spinedi E. , Hadid R. , Jacquier M.-C. , Giacomini M. , Gaillard R. C.
Published: March 2007

The potential role of endogenous sex hormones in regulating hypothalamo–pituitary–adrenal (HPA) axis function was investigated after a single injection of endotoxin in adult (8 week old) BALB/c mice of both sexes. The effect of LPS on plasma ACTH, corticosterone (B), testosterone and oestradiol (E) levels and on anterior pituitary (AP) ACTH and adrenal B contents at different times after treatment was studied. The results indicate that: (a) basal B but not ACTH plasma levels were significantly higher in female than in male mice; (b) LPS significantly increased both ACTH and B plasma levels over the baseline 2 h after injection, both hormone levels being higher in female than in male mice; (c) although plasma ACTH concentrations recovered the basal value at 72 h after LPS in animals of both sexes, plasma B levels returned to the baseline only at 120 h after treatment; (d) E plasma levels significantly increased 2 h after LPS and returned to the baseline at 72 h post‐treatment, in both sexes; (e) at 2 h after LPS, testosterone plasma levels significantly decreased in male mice and increased in female mice, recovering the baseline level at 120 and 72 h after LPS, respectively; (f) AP ACTH content was similar in both sexes in basal condition and it was significantly diminished 72 h post‐treatment without sex difference; whereas AP ACTH returned to basal content 120 h after LPS in males, it remained significantly decreased in females; (g) basal adrenal B content was higher in female than in male mice, and it significantly increased in both sexes 2 h post‐LPS, maintaining this sex difference. Whereas adrenal B returned to basal content 72 h after treatment in male mice, it remained significantly enhanced up to 120 h post‐LPS in female animals. The data demonstrate the existence of a clear sexual dimorphism in basal condition and during the acute phase response as well as in the recovery of the HPA axis function shortly after infection.
NPC 15669 blocks neutrophil CD18 increase and lung injury during cardiopulmonary bypass in pigs
Authors: Bator J. M. , Gillinov A. M. , Zehr K. J. , Redmond J. M. , Wilson I. C. , Herskowitz A. , Connor J. R. , Burch R. M. , Cameron D. E.
Published: March 2007

During cardiopulmonary bypass (CPB), neutrophils become activated due to contact with extracorporeal surfaces and binding of complement fragments C3a and C5a, leading to extravasation and subsequent tissue damage. In this study, the effects of the leumedin NPC 15669 (N [9H ‐ (2,7 dimethylfluorenyl ‐ 9 ‐ methoxy) car bonyl]‐L‐leucine), a leukocyte recruitment inhibitor, were evaluated in a pig model of CPB. NPC 15669 caused significant inhibition of CPB associated increase in CD18 upregulation, lung tissue myeloperoxidase content, and percentage wet weight compared to controls. Lung histology revealed clear airways and minimal neutrophil infiltration in treated animals vs. significant oedema and cellular infiltration in controls. It is concluded that CPB causes a dramatic increase in neutrophil CD18, and that leumedins are effective in inhibiting neutrophil activation and subsequent tissue injury when administered during CPB.
Hormonal control of inflammatory responses
Authors: Garcia-Leme J. , Farsky Sandra P.
Published: March 2007

Almost any stage of inflammatory and immunological responses is affected by hormone actions. This provides the basis for the suggestion that hormones act as modulators of the host reaction against trauma and infection. Specific hormone receptors are detected in the reactive structures in inflamed areas and binding of hormone molecules to such receptors results in the generation of signals that influence cell functions relevant for the development of inflammatory responses. Diversity of hormonal functions accounts for recognized pro‐ and anti‐inflammatory effects exerted by these substances. Most hormone systems are capable of influencing inflammatory events. Insulin and glucocorticoids, however, exert direct regulatory effects at concentrations usually found in plasma. Insulin is endowed with facilitatory actions on vascular reactivity to inflammatory mediators and inflammatory cell functions. Increased concentrations of circulating glucocorticoids at the early stages of inflammation results in downregulation of inflammatory responses. Oestrogens markedly reduce the response to injury in a variety of experimental models. Glucagon and thyroid hormones exert indirect anti‐inflammatory effects mediated by the activity of the adrenal cortex. Accordingly, inflammation is not only merely a local response, but a hormone‐controlled process.
Desensitization of delayed‐type hypersensitivity in mice: suppressive environment
Authors: Katsura Takashi , Kobayashi Kazuo , Hosaka Michio , Sugihara Sachiko , Kasama Tsuyoshi , Kasahara Keita , Cohen Stanley , Yoshida Takeshi
Published: March 2007

The systemic injection of high doses of antigen into a preimmunized animal results in transient unresponsiveness of cell‐mediated immune responses. This phenomenon is known as desensitization. Serum interleukin 2 (IL‐2) activity was found transiently in desensitized mice at 3 h after the antigen challenge. These mice could not reveal antigen nonspecific delayed‐type hypersensitivity (DTH) 1 d after the challenge. Specific suppression of DTH was observed at later stages. Sera from 3 h desensitized mice showed suppressive effects on DTH in preo immunized mice. Administration of recombinant IL‐2 into preimmunized mice led to the failure of development of DTH to antigens. These observations suggest that IL‐2 plays an important role in the suppressive environment.
The effect of inhibition of leukotriene synthesis on the activity of interleukin‐8 and granulocyte‐macrophage colony‐stimulating factor
Authors: Roberts P. J. , Pizzey A. R. , Linch D. C.
Published: March 2007

The cytokines interleukin‐8 (IL‐8) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) enhanced the extracellular release of arachidonate metabolites from ionophore‐stimulated neutrophils by 145 ± 10% (mean ± S.E.M., n = 13) and 182 ± 11% (n = 16), respectively. To determine whether enhanced leukotriene production mediates the effects of these cytokines on neutrophil activity, two different specific arachidonate 5‐lipoxygenase (5‐LO) inhibitors, piriprost and MK‐886, were used to inhibit leukotriene synthesis. Neither inhibitor affected the upregulation of CD11b β2‐integrin expression or priming of superoxide generation stimulated by IL‐8 and GM‐CSF. It is concluded that leukotrienes do not mediate either the direct or priming effects of these cytokines and that these classes of anti‐inflammatory drugs are therefore unlikely to inhibit the effects of IL‐8 and GM‐CSF on neutrophil activation.
The temporal relationship between the neural and vascular actions of kallidin within the nose
Authors: Rajakulasingam K. , Lau L. C. K. , Polosa R. , Church M. K. , Holgate S. T. , Howarth P. H.
Published: March 2007

The time course of effect of the B2‐receptor agonist kallidin (K) on induced changes of nasal airflow, rhinorrhoea, nasal pain, sneezing and nasal microvascular leakage has been examined and compared with its B2 metabolite agonist bradykinin (B) and the B1‐agonist [des‐arg9]‐bradykinin (D). When administered as a single dose K and B induced an immediate sensation of pain, rhinorrhoea, elevations in lavage albumin and protein levels and a sustained increase in nasal airways resistance (NAR) for 5–40 min post‐challenge. [des‐arg9]‐Bradykinin and vehicle placebo (V) were without effect on any of these indices. These studies identify the action of K and B within the nose and differentiate the neural and vascular effects of these kinins in addition to suggesting the potential that nasal blockage and nasal microvascular leakage represent alterations in differing vascular compartments. These findings have implications for the understanding and therapeutic manipulation of rhinitis.
Immunomodulatory role of phagocyte‐derived chloramines involving lymphocyte glutathione
Authors: Witko-Sarsat Véronique , Nguyen Anh Thu , Descamps-Latscha Béatrice
Published: March 2007

This study shows that human lymphocytes markedly decrease chloramines (long‐lived oxidants) generated by polymorphonuclear neutrophils (PMN) after stimulation by phorbol‐myristate‐acetate or opsonized zymosan. In a cell‐free model, reduced glutathione (GSH) scavenged chloramines, giving rise to oxidized glutathione (GSSG). In the cell system, treatment of lymphocytes with autologous PMN‐derived chloramines induced a profound decrease in their total and reduced glutathione (GSH) content and markedly inhibited their proliferate responses to concanavalin‐A and, to a lesser extent, phytohaemagglutinin. It is concluded that (i) lymphocytes may play a defensive role against phagocyte‐derived oxidative stress by scavenging chloramines, and (ii) as this effect which is mediated by GSH affects lymphocyte proliferative responses, it may help to elucidate the still obscure mechanisms of oxidative stress associated immunodeficiency.
Stress induced experimental colitis
Authors: Stein T. A. , Keegan L. , Auguste L.-J. , Bailey B. , Wise L.
Published: March 2007

Stress induces chemical changes in the central nervous system which alters the biochemistry and physiology of the digestive tract. The present study determines arachidonic acid oxidation and damage in the colon following stress. Ten rats were stressed by the cold‐restraint method; ten were controls. Stress induced 0.5 ± 0.7 (S.D.) mucosal erosions whereas controls had none. Subepithelial hemorrhage and erosions occurred only in the proximal two‐thirds of the colon. Prostaglandin E2 synthesis was increased after stress compared to the control (381 ± 130 vs. 1610 ± 372 ng/g/min). Leukotriene C4 synthesis also increased after stress (4217 ± 994 vs. 11300 ± 1662 ng/g/min). Synthesis of prostaglandin E2 increased (r = 0.9381) with leukotriene C4. The response of the colon to stress is less severe than that in the stomach and may be related to regional regulation of prostaglandin and leukotriene synthesis.
Glucocorticoids as cytokine inhibitors: role in neuroendocrine control and therapy of inflammatory diseases
Authors: Fantuzzi Giamila , Ghezzi Pietro
Published: March 2007

Glucocorticoids are potent inhibitors of inflammation and endotoxic shock. This probably occurs through an inhibition of the synthesis of pro‐inflammatory cytokines as well as of many of their toxic activities. Therefore, endogenous glucocorticoids (GC) might represent a major mechanism in the control of cytokine mediated pathologies. GC inhibit the synthesis of cytokines in various experimental models. Adrenalectomy or GC antagonists potentiate TNF, IL‐1 and IL‐6 production in LPS treated mice. GC inhibit the formation of arachidonic acid metabolites and the induction of NO synthase. They also inhibit various activities of cytokines including toxicity, haemodynamic shock and fever. Adrenalectomy sensitizes to the toxic effects of LPS, TNF and IL‐1. On the other hand, GC potentiate the synthesis of several cytokine induced APP by the liver. Since many of these proteins have anti‐toxic activities (antioxidant, antiprotease etc.) or bind cytokines, this might well represent a GC mediated protective feedback mechanism involving the liver. Not only do GC inhibit cytokines, but in vivo LPS and various cytokines (TNF, IL‐1, IL‐6) increase blood GC levels through a central mechanism involving the activation of the HPA. Thus, this neuroendocrine response to cytokines constitutes an important immunoregulatory feedback involving the brain.
Sequences of acetyl CoA carboxylase promoter for tumour necrosis factor action
Authors: Park Keerang , Pape Michael E. , Kim Ki-Han
Published: March 2007

Tumour necrosis factor (TNF) inhibits the accumulation of acetyl CoA carboxylase (ACC) mRNA by decreasing the rate of ACC gene transcription. The ACC mRNA species found in 30A5 cells are generated from promoter II and TNF inhibits the accumulation of class 2 type mRNAs. By using 5′ deletion mutants of promoter II fused to the bacterial chloramphenicol acetyltransferase (CAT) gene, the DNA mobility shift assay and the DNase I footprinting assay, the authors have identified the 30 bp from −389 to −359 as the TNF responsive element in promoter II. TNF treatment causes a decrease in the binding activity of nuclear protein(s) specific to the TNF responsive element. When the fragment containing the TNF responsive element was incorporated into the thymidine kinase promoter, the chimeric gene exhibited TNF induced inhibition of expression.