Role of tumor necrosis factor-alpha in endotoxin-induced lung parenchymal hyporesponsiveness in mice

Although changes in airway responsiveness in pulmonary inflammation are commonly related to the action of infiltrated leukocytes, our previous report suggested a direct role of inflammatory cytokines in LPS-induced lung hyporesponsiveness. The aim of this study was to define if cytokines detected in the BALF (bronchoalveolar lavage fluid) of intratracheal LPS-treated mice could be, at least in part, responsible for 5-HT (5-hydroxytryptamine) lung hyporeactivity. Our results show that intratracheal instillation of LPS induced a time-dependent increase in IL-(interleukin-)1beta, IL-6, and TNF (tumor necrosis factor)alpha in the BALF. Cytokine production was paralleled by 5-HT lung hyporesponsiveness, and intratracheal administration of TNFalpha proved to be very efficient in inhibiting 5-HT responsiveness. In addition, systemic treatment with rolipram, an inhibitor of TNFalpha production, was paralleled by a significant recovery of lung responsiveness. On the contrary, IL-1beta and IL-6 were not demonstrated to play a relevant role in 5-HT hyporesponsiveness. It is concluded that TNFalpha could be a crucial mediator of LPS-induced lung hyporesponsiveness.

Selective inhibition of interleukin-8-induced neutrophil chemotaxis by ketoprofen isomers

Although it is commonly accepted that the anti-inflammatory effect of nonsteroidal anti-inflammatory drugs (NSAIDs) is mainly associated to their ability to inhibit the cyclooxygenase (COX) enzyme system, several results indicate that non-COX mechanisms could be important in the therapeutical effect of these drugs. The aim of this study was to define if NSAIDs could exert, at least in part, their anti-inflammatory effect by inhibiting the activities of human polymorphonuclear leukocytes (PMNs) triggered by chemotactic stimuli and, if so, to understand the relationship of this effect with COX inhibition. A unique opportunity to dissociate the inhibition of prostaglandin (PG) synthesis from other therapeutical properties of NSAIDs is constituted by ketoprofen isomers being the S-isomer 100 time more potent than R-isomer on COX inhibition. Our results show that R- and S-ketoprofen, independently of their potency as PG inhibitors, proved very efficacious in selective inhibition of interleukin-8 (IL-8) chemotaxis. Inhibition of IL-8 chemotaxis was not restricted to ketoprofen isomer as it could be observed also with drugs belonging to different classes of NSAIDs and it was obtained at drug concentration superimposable to plasma levels after therapeutic administration in patients. Reduction of IL-8 migration by ketoprofen isomers was paralleled by selective inhibition of PMN response in terms of intracellular calcium concentration ([Ca(2+)]i) increase and extracellular signal regulated kinase(ERK)-2 activation, two intracellular mediators reported to be critical for PMN activities. It is concluded that inhibition of IL-8 chemotaxis could represent a new clinical target for ketoprofen isomers and, in fact, contribute to the anti-inflammatory activity of NSAIDs.

Nerve and seminal sparing radical cystectomy with orthotopic urinary diversion for select patients with superficial bladder cancer: an innovative surgical approach

PURPOSE

Radical cystectomy is advocated for high risk patients with superficial bladder cancer. To preserve complete urinary continence, normal sexual function and fertility in young patients, we developed an innovative technique based on nerve and seminal sparing radical cystectomy.

MATERIALS AND METHODS

Radical cystectomy was recommended for 8 patients with superficial bladder cancer that was not conservatively manageable. Average patient age was 44 years (range 36 to 48), and all patients were extremely anxious to maintain potency and fertility. The surgical procedure consisted of transurethral resection of the prostate, pelvic iliac lymph node dissection and extraperitoneal radical cystectomy performed while preserving the vas deferens seminal vesicles and neurovascular bundles. Urinary diversion was accomplished with a W-shaped ileal reservoir anastomosed to the prostatic capsule.

RESULTS

Patients were generally discharged from the hospital 15 days after surgery, and postoperative morbidity was limited. Daytime and nighttime continence was immediate and complete after catheter removal. Normal erectile function was clinically documented in all patients while fertility potential with semen retrieval via urine was recorded in 7. The quality of life, as reported by the patients, was highly satisfactory at 18-month followup.

CONCLUSIONS

The surgical approach we describe should be considered in young men with clinical, superficial bladder tumors refractory to conservative treatment who wish to maintain potency and fertility, and to guarantee as good a quality of life as possible. To ensure oncological success scrupulous patient selection is a primary step of this procedure.

Lps induces IL-6 in the brain and in serum largely through TNF production

We investigated the relative contribution of IL-6 and PGE2 directly induced by LPS and indirectly induced via TNF, using in vivo and in vitro models in the mouse. In these models we have used as tools an anti-TNF antibody and a cyclooxygenase inhibitor, the S enantiomer of ketoprofen (S-KPF). Anti-TNF antibodies inhibited LPS-induced IL-6 production in three different models: IL-6 production by mouse peritoneal macrophages in vitro; serum IL-6 levels induced by intraperitoneal LPS; and brain IL-6 levels induced by an intracerebroventricular injection of LPS. However, in vitro anti-TNF antibodies, did not inhibit LPS-induced PGE2, indicating that this effect is not mediated by TNF. Since PGE2 has an opposite effect on TNF and IL-6 production, inhibiting that of TNF but inducing that of IL-6, we investigated the effect of S-KPF on TNF and IL-6 production in vivo following LPS injection. Both TNF and IL-6 induction was augmented by S-KPF, but anti-TNF antibodies abolished the augmentation of IL-6 production. Thus, the effect of anti-inflammatory drugs on IL-6 production in some models can be secondary to their effect on TNF production.

Lipopolysaccharide-induced lung injury in mice. II. Evaluation of functional damage in isolated parenchyma strips

Pulmonary inflammatory diseases are characterized by changes in airway responsiveness. This phenomenon is commonly related to the action of inflammatory mediators produced by infiltrated leukocytes. The aim of this study was to investigate in an ex vivo experimental model the effect of acute instillation of lipopolysaccharide (bacterial endotoxin; LPS) on lung parenchyma contractility. We firstly characterized the responsiveness of isolated murine lung to airway stimuli. Murine parenchymal strips were found to be mainly sensitive to 5-hydroxytryptamine (5-HT) while the cholinergic agonist, methacholine (MCh), evoked a smaller contractile response. 5-HT responsiveness was inhibited by methysergide. No significant parenchymal contraction was evoked by histamine, substance P and bradykinin. Lung responsiveness to 5-HT was significantly reduced by in vivo LPS treatment and this effect was only partially paralleled by leukocyte infiltration. In addition, LPS-induced hyporesponsiveness was significantly inhibited by betamethasone (BMS) or pentoxifylline (PTX) pretreatment suggesting that 5-HT lung hyporesponsiveness could be mediated by LPS-induced inflammatory mediators such as inflammatory cytokines.

R- and S-isomers of nonsteroidal anti-inflammatory drugs differentially regulate cytokine production

2-arylpropionic acids, a well known class of non-steroidal anti-inflammatory drugs (NSAIDs), exist as a racemic mixture of their enantiomeric forms, with S-isomers primarily responsible for inhibition of prostaglandin (PG) production and of inflammatory events. In this study we show that S-isomers are also responsible for the paradoxical up-regulation of tumor necrosis factor (TNF) induced by ketoprofen, flurbiprofen and ibuprofen in murine peritoneal macrophages stimulated by bacterial endotoxin (LPS). This effect is in close correlation with cyclooxygenase inhibitory capacity of S-isomers and, from Northern blot analysis, seems to be mediated by the up-regulation of TNF mRNA. In addition, up-regulation of TNF production by S-isomers is associated with inhibition of interleukin-10 (IL-10) production. Conversely, we have observed that S-enantiomers reduce IL-6 production at a concentration 100 times higher than that able to inhibit cyclooxygenase activity. The unwanted pro-inflammatory effects of S-isomers through TNF and IL-10 production could therefore hinder their analgesic effect, that is, at least in part, related to IL-6 inhibition. In addition, TNF amplification by S-isomers could be correlated to the clinical evidence of their gastric toxicity. On the other hand, R-isomers did not affect TNF and IL-10 production even at cyclooxygenase-blocking concentration, while they reduced IL-6 production to the same levels as S-isomers. It is concluded that the regulation of cytokine production by S-isomers of 2-arylpropionic acids could partially mask their therapeutic effects and could be correlated to the clinical evidence of their higher gastric toxicity. On the other hand, IL-6 inhibition without the unwanted effects on TNF and IL-10 production shown by R-isomers could be correlated to the analgesic effect reported for R-2-arylpropionic acids.

Characterization and properties of dominant-negative mutants of the ras-specific guanine nucleotide exchange factor CDC25(Mm)

Ras proteins are small GTPases playing a pivotal role in cell proliferation and differentiation. Their activation depends on the competing action of GTPase activating proteins and guanine nucleotide exchange factors (GEF). The properties of two dominant-negative mutants within the catalytic domains of the ras-specific GEF, CDC25(Mm), are described. In vitro, the mutant GEF(W1056E) and GEF(T1184E) proteins are catalytically inactive, are able to efficiently displace wild-type GEF from p21(ras), and strongly reduce affinity of the nucleotide-free ras x GEF complex for the incoming nucleotide, thus resulting in the formation of a stable ras.GEF binary complex. Consistent with their in vitro properties, the two mutant GEFs bring about a dramatic reduction in ras-dependent fos-luciferase activity in mouse fibroblasts. The stable ectopic expression of the GEF(W1056E) mutant in smooth muscle cells effectively reduced growth rate and DNA synthesis with no detectable morphological changes.

Peripheral blood mononuclear cell production of interleukin-8 and IL-8-dependent neutrophil function in hypercholesterolemic patients

Interleukin-8 is a cytokine produced by mononuclear cells that is involved in polymorphonuclear neutrophil leukocyte (PMN) recruitment and activation. Several studies have previously demonstrated a leukocyte activation during hypercholesterolemia and 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have been found to play a role in the prevention of atherothrombotic disease. The purpose of this study was to determine interleukin-8 (IL-8) mRNA expression and ex vivo production from peripheral blood mononuclear cells (PBMCs) and IL-8-dependent PMN activation of hypercholesterolemic (HC) patients with respect to normocholesterolemic (NC) subjects. Using Northern blot analysis, we found a four- and threefold increase in the amount of IL-8 transcript in PBMC from HC patients, in unstimulated and LPS stimulated cultures, respectively. A specific immunoassay showed a correspondingly significant increase of IL-8 immunoactivity in the conditioned medium of PBMC from HC subjects as compared with controls (unstimulated PBMC: 15 +/- 4 vs. 4.2 +/- 3 ng/ml; P < 0.0001; LPS stimulated PBMC: 65.3 +/- 8 vs. 36.6 +/- 9 ng/ml; P < 0.0001). PMN of HC patients stimulated with IL-8 showed a reduced elastase release with respect to NC subjects before physiological granule release after f-Met-Leu-Phe (fMLP) treatment. These results indicate an upregulation of the IL-8 system in dyslipidemic patients and provide evidence for ongoing in vivo IL-8-dependent PMN activation during hypercholesterolemia.

Thioredoxin, a redox enzyme released in infection and inflammation, is a unique chemoattractant for neutrophils, monocytes, and T cells

Thioredoxin (Trx) is a ubiquitous intracellular protein disulfide oxidoreductase with a CXXC active site that can be released by various cell types upon activation. We show here that Trx is chemotactic for monocytes, polymorphonuclear leukocytes, and T lymphocytes, both in vitro in the standard micro Boyden chamber migration assay and in vivo in the mouse air pouch model. The potency of the chemotactic action of Trx for all leukocyte populations is in the nanomolar range, comparable with that of known chemokines. However, Trx does not increase intracellular Ca2+ and its activity is not inhibited by pertussis toxin. Thus, the chemotactic action of Trx differs from that of known chemokines in that it is G protein independent. Mutation of the active site cysteines resulted in loss of chemotactic activity, suggesting that the latter is mediated by the enzyme activity of Trx. Trx also accounted for part of the chemotactic activity released by human T lymphotropic virus (HTLV)-1-infected cells, which was inhibited by incubation with anti-Trx antibody. Since Trx production is induced by oxidants, it represents a link between oxidative stress and inflammation that is of particular interest because circulating Trx levels are elevated in inflammatory diseases and HIV infection.

Differential contribution of R and S isomers in ketoprofen anti-inflammatory activity: role of cytokine modulation

Among nonsteroidal anti-inflammatory drugs (NSAIDs), 2-arylpropionic acids exist as a racemic mixture of its enantiomeric forms, with S-enantiomers primarily responsible for inhibition of prostaglandin synthesis and of inflammatory events. The aim of this study was to compare the anti-inflammatory effects of R- and S-ketoprofen in vitro and in vivo. S-Ketoprofen efficiently inhibited carrageenan-induced edema formation, but it could also amplify the LPS-induced production of the inflammatory cytokines tumor necrosis factor (TNF) and interleukin-1 (IL-1), in close correlation with its ability to inhibit prostaglandin synthesis. Because these inflammatory cytokines are among the factors involved in carrageenan-induced inflammation and also are possibly involved in gastric damage, enhanced cytokine production could partially mask the analgesic effect of S-ketoprofen, and it can be associated with the clinical evidence of its gastric toxicity. On the other hand, R-ketoprofen contributes to the overall activity of the racemate, by playing the main role in ketoprofen-induced analgesia. Unlike the S-isomer, R-ketoprofen did not induce a significant increase of cytokine production even at cyclooxygenase-blocking concentrations. It is concluded that the R-isomer directly contributes to the anti-inflammatory effects of ketoprofen, being more analgesic, and because it does not amplify inflammatory cytokine production.

Corticosteroid-independent inhibition of tumor necrosis factor production by the neuropeptide urocortin

Urocortin (UCN) is a neuropeptide homologous with corticotropin-releasing factor (CRF), which has anti-inflammatory activities not all mediated by corticosteroids. In mice, UCN (1 microg/mouse sc) significantly reduced lipopolysaccharide (LPS)-induced serum tumor necrosis factor (TNF) and interleukin (IL)-1beta levels in vivo but did not affect serum IL-6. These effects were paralleled by a rise in corticosterone (CS) levels. Blockade of the CS increase by cyanoketone did not prevent TNF inhibition by UCN, suggesting the neuropeptide has anti-inflammatory mechanisms independent of the hypothalamus-pituitary-adrenal axis. In fact UCN had a direct inhibitory effect on LPS-induced TNF in rat Kupffer cells at concentrations between 10(-10) and 10(-16) M, and this effect was related to increased cAMP levels. However, the in vivo inhibition of LPS-induced IL-1beta by UCN was reversed by cyanoketone, indicating that the increase of endogenous glucocorticoids might be more important in IL-1beta inhibition than in TNF inhibition by UCN.

Tartronates: a new generation of drugs affecting bone metabolism

In the search for a new class of bone-sparing agents for treating osteopenic disorders, we hypothesized that tartronic acid derivatives, sharing the chemical characteristics both of bisphosphonates and of Gla residues contained in matrix proteins such as osteocalcin, could positively affect bone metabolism. A series of tartronates was therefore tested for their ability to affect bone metabolism. In vitro resorption tests were performed examining pit formation by freshly isolated rat and rabbit osteoclasts plated onto bone slices and exposed to the drugs for 48 h. Tartronates bearing a linear side-chain (DF 1222 and DF 1363A) were the most effective in inhibiting pit excavation in the pM-nM range. Tartronates did not affect osteoclast viability, number, adhesion, or tartrate resistant acid phosphatase activity. Transient cell retraction was observed in osteoclasts plated onto glass and exposed to DF 1222. The maximal effect was seen in cells treated for 4 h at a concentration of 1 pM. DF 1222 accelerated mineralization in cultures of periosteal cells without affecting other osteoblast-like functions. This product was therefore tested in vivo in ovariectomized mice. Bone mass in femur was evaluated, by ash gravimetry, 21 days after ovariectomy. Unfortunately, DF 1222, the most active of tartronates in vitro, was inactive in this test because of its high hydrophilicity and the subsequent too short residence time. On the contrary, its tetrahydropyranyl ether derivative, DF 1363A, endowed with a significantly higher lipophilicity, showed a dose-dependent bone-sparing effect when administered subcutaneously at 10, 30, and 100 mg/kg/die, thus confirming the activity seen in in vitro tests. Because of their feasible parallel effect on both bone resorption and formation, tartronate derivatives may be tested to candidate this class of products for clinical studies.

Interleukin-1 beta primes interleukin-8-stimulated chemotaxis and elastase release in human neutrophils via its type I receptor

Interleukin-1 (IL-1) is a pleiotropic proinflammatory cytokine which binds to human neutrophils (PMN) and can directly or indirectly activate their functions. In this study we show that a brief exposure to IL-1 beta induces a potentiation of both PMN elastase release and chemotactic response to interleukin-8 (IL-8), the prototype of C-X-C chemokines. Priming by IL-1 beta was maximal at 100 ng/ml, was completely blocked in the presence of IL-1 receptor antagonist (IL-1ra) and, in the chemotaxis assay, was best observed at suboptimal (3-6 ng/ml) or inactive (0.75 ng/ml) concentrations of IL-8. Priming of PMN by IL-1 beta was completely blocked by M1, a specific antibody against the type I IL-1 receptor (IL-1RI). On the other hand M22, an antibody directed against the IL-1 decoy type II IL-1 receptor did not affect IL-1 beta action and slightly increased the priming effect. Thus, exclusively via its type I receptor, IL-1 beta can act on PMN at multiple levels, by promoting their accumulation in tissues through the induction of chemotactic factors (e.g. IL-8) and the upregulation of adhesion molecules, and by priming their response to chemotactic agonists.

Inhibitory activity of IL-1 receptor antagonist depends on the balance between binding capacity for IL-1 receptor type 1 and IL-1 receptor type II

A series of mutants of human IL-1 receptor antagonist (IL-1ra) has been designed by comparison of IL-1ra and IL-1beta structures in order to increase receptor antagonist capacity. Upon in vitro and in vivo assay of IL-1 antagonism, the IL-1ra mutants DoB 0039 (N91--&gt;R), DoB 0040 (T109--&gt;A) and DoB 0041 (N91/T109--&gt;R/A) could inhibit IL-1beta effects more efficiently than wild-type IL-1ra, with DoB 0041 being the most active. Analysis of the receptor-binding capacity of the IL-1ra mutants showed that all three mutants could inhibit binding of IL-1alpha or IL-1beta to IL-1RI-bearing cells more efficiently than wild-type IL-1ra. Conversely, binding of IL-1beta to IL-1RII-bearing cells could be inhibited by DoB 0041 much less efficiently than by wild-type IL-1ra. It is known that the two types of IL-1 receptors (IL-1RI and IL-1RII) play different roles in the regulation of IL-1 activity, with IL-1RI being solely responsible for cell triggering upon IL-1 binding, whereas IL-1RII acts as a scavenger of IL-1 and can thus be considered as a natural IL-1 inhibitor. Thus, the enhanced inhibitory capacity of DoB 0041 as compared with wild-type IL-1ra is explained in terms of better binding to the activating receptor IL-1RI and poorer interaction with the inhibitory receptor IL-1RII.

Inhibitory activity of IL-1 receptor antagonist depends on the balance between binding capacity for IL-1 receptor type 1 and IL-1 receptor type II

A series of mutants of human IL-1 receptor antagonist (IL-1ra) has been designed by comparison of IL-1ra and IL-1beta structures in order to increase receptor antagonist capacity. Upon in vitro and in vivo assay of IL-1 antagonism, the IL-1ra mutants DoB 0039 (N91-->R), DoB 0040 (T109-->A) and DoB 0041 (N91/T109-->R/A) could inhibit IL-1beta effects more efficiently than wild-type IL-1ra, with DoB 0041 being the most active. Analysis of the receptor-binding capacity of the IL-1ra mutants showed that all three mutants could inhibit binding of IL-1alpha or IL-1beta to IL-1RI-bearing cells more efficiently than wild-type IL-1ra. Conversely, binding of IL-1beta to IL-1RII-bearing cells could be inhibited by DoB 0041 much less efficiently than by wild-type IL-1ra. It is known that the two types of IL-1 receptors (IL-1RI and IL-1RII) play different roles in the regulation of IL-1 activity, with IL-1RI being solely responsible for cell triggering upon IL-1 binding, whereas IL-1RII acts as a scavenger of IL-1 and can thus be considered as a natural IL-1 inhibitor. Thus, the enhanced inhibitory capacity of DoB 0041 as compared with wild-type IL-1ra is explained in terms of better binding to the activating receptor IL-1RI and poorer interaction with the inhibitory receptor IL-1RII.

Mechanism of inhibition of tumor necrosis factor production by chlorpromazine and its derivatives in mice

In previous work, we reported that chlorpromazine inhibits tumor necrosis factor (TNF) production in endotoxin lipopolysaccharide-treated mice, and protects against lipopolysaccharide toxicity. Chlorpromazine is used as an antipsychotic and has several effects on the central nervous system. It acts on different neurotransmitter receptors and has other biochemical activities some of which, like inhibition of phospholipase A2, might be responsible for the inhibitory effect on TNF production. To investigate the role of these actions in the inhibition of TNF production by chlorpromazine, we have synthesized some chlorpromazine derivatives that do not have central activities. Some of these analogs have lost their affinity for various receptors and their phospholipase A2 inhibitory activity, but still inhibit TNF production. No correlation was found between TNF inhibition and the ability to inhibit nitric oxide (NO) synthase, whereas a good correlation was evident between TNF inhibition and antioxidant activity.

IL-1 beta primes IL-8-activated human neutrophils for elastase release, phospholipase D activity, and calcium flux

Interleukin-8 (IL-8), the prototype of the alpha (e.i., C-X-C branch) chemokine family, induced elastase release in a concentration-dependent manner (50-1000 ng/mL) in cytochalasin B-treated human polymorphonuclear leukocytes (PMNs). This response was potentiated about twofold if PMNs were preexposed to interleukin-1 beta (IL-1 beta) at concentrations that were by themselves inactive. The effect of IL-1 beta was clearly observed after 5 min and was maximal after a 30-min preincubation of the cells. The effect was present over the whole active concentration range of IL-8 and was completely blocked by the presence of IL-1 receptor antagonist. Priming of elastase release by IL-1 beta was not associated with a change in receptor number or affinity for IL-8. On the contrary, it was correlated with priming of phospholipase D activity and calcium flux activated by IL-8. Preincubation of the cells with ethanol and/or La3+ inhibited IL-8-induced degranulations, suggesting that activation of phospholipase D and increase of [Ca2+]i were important for this response. In contrast, ethanol and La3+ did not decrease the priming effect of IL-1 beta. IL-8 and IL-1 beta have been shown to be released by the same cell types and may be concomitantly present at sites of inflammation, giving rise to an amplification of the inflammatory response.

Transfected type II interleukin-1 receptor impairs responsiveness of human keratinocytes to interleukin-1

Of the two known types of specific receptors for interleukin (IL)-1, the function of the type II IL-1 receptor (IL-1RII) is still elusive. IL-1RII is allegedly devoid of signaling capacity and is therefore thought to act by trapping and inhibiting IL-1. To directly assess the functional role of IL-1RII, a human keratinocyte cell line has been stably transfected with a cDNA coding for IL-1RII, and its responsiveness to IL-1 has been compared with that of nontransfected cells. Parental cells express IL-1RI and are responsive to low doses of IL-1, whereas transfected cells overexpress IL-1RII, both in its membrane and soluble form, and show a dramatically impaired response to IL-1. Selective block of IL-1RII restores the ability of transfected keratinocytes to respond to IL-1, indicating that the overexpressed IL-1RII is in fact uniquely responsible for their refractoriness to IL-1. The main mechanism of unresponsiveness in transfected keratinocytes appears to be the capture and neutralization of IL-1 by the soluble form of IL-1RII.

Mapping of receptor binding sites on IL-1 beta by reconstruction of IL-1ra-like domains

Upon structure comparison between IL-1 beta and its antagonist IL-1ra, single or multiple residues along the IL-1 beta sequence were replaced with the corresponding amino acids present in the IL-1ra protein, in the attempt to identify sites important for receptor binding and for biologic activity on the two molecules. Ten of fifteen mutant proteins had activity comparable to that of wild-type IL-1 beta in three different biologic assays and in receptor binding, indicating that the introduced changes did not influence the functional structure of the protein. Conversely, three mutants (SMIL-9: 127/263 R/T--&gt;W/Y; SMIL-10: 125/127/263/265 T/R/T/Q--&gt;R/W/Y/E; SMIL-15:222/227 I/E--&gt;S/S) showed an increased binding capacity for IL-1RI, not paralleled by increased agonist activity, indicating that the introduced IL-1ra residues could be involved in the nonagonist IL-1RI binding site. On the other hand, two mutants showed diminished binding capacity with concomitant decrease in biologic activity. Both mutants (SMIL-1, five substitutions in the loop 202-214; and SMIL-3, total replacement of the loop 164-173 with the IL-1ra stretch 52-55) included substitutions of residues allegedly important for agonist binding to IL-1RI. Mutant SMIL-3 showed the most profound reduction in binding capacity for IL-1RI (CDw121a) and a more than 1,000-fold reduced biologic activity both in vitro and in vivo, but it retained full capacity of binding to IL-1RII (CDw121b) and acted as a selective antagonist of IL-1RII. From these results the following conclusions can be drawn. IL-1 beta binds to IL-1RI and to IL-1RII through different sites, and the loop 164-173 appears as one of the areas involved in the selective interaction with IL-1RI. Agonist (IL-1 beta) and nonagonist (IL-1ra) binding to IL-1RI occur through distinct sites, with loops 164-173 and 202-214 of IL-1 beta identified as two of the sites selectively involved in agonist binding to the activating receptor.

Mapping of receptor binding sites on IL-1 beta by reconstruction of IL-1ra-like domains

Upon structure comparison between IL-1 beta and its antagonist IL-1ra, single or multiple residues along the IL-1 beta sequence were replaced with the corresponding amino acids present in the IL-1ra protein, in the attempt to identify sites important for receptor binding and for biologic activity on the two molecules. Ten of fifteen mutant proteins had activity comparable to that of wild-type IL-1 beta in three different biologic assays and in receptor binding, indicating that the introduced changes did not influence the functional structure of the protein. Conversely, three mutants (SMIL-9: 127/263 R/T-->W/Y; SMIL-10: 125/127/263/265 T/R/T/Q-->R/W/Y/E; SMIL-15:222/227 I/E-->S/S) showed an increased binding capacity for IL-1RI, not paralleled by increased agonist activity, indicating that the introduced IL-1ra residues could be involved in the nonagonist IL-1RI binding site. On the other hand, two mutants showed diminished binding capacity with concomitant decrease in biologic activity. Both mutants (SMIL-1, five substitutions in the loop 202-214; and SMIL-3, total replacement of the loop 164-173 with the IL-1ra stretch 52-55) included substitutions of residues allegedly important for agonist binding to IL-1RI. Mutant SMIL-3 showed the most profound reduction in binding capacity for IL-1RI (CDw121a) and a more than 1,000-fold reduced biologic activity both in vitro and in vivo, but it retained full capacity of binding to IL-1RII (CDw121b) and acted as a selective antagonist of IL-1RII. From these results the following conclusions can be drawn. IL-1 beta binds to IL-1RI and to IL-1RII through different sites, and the loop 164-173 appears as one of the areas involved in the selective interaction with IL-1RI. Agonist (IL-1 beta) and nonagonist (IL-1ra) binding to IL-1RI occur through distinct sites, with loops 164-173 and 202-214 of IL-1 beta identified as two of the sites selectively involved in agonist binding to the activating receptor.

Single-cell analysis of macrophage chemotactic protein-1-regulated cytosolic Ca2+ increase in human adherent monocytes

The increase in intracellular free Ca2+ ([Ca2+]i) associated with interaction of monocyte chemotactic protein-1 (MCP-1) and related chemokines beta with adherent human blood monocytes was investigated at the single-cell level. We used f-MLP as reference chemotactic agent. MCP-1 caused an increase in [Ca2+]i in individual adherent monocytes, with 95% of cells responding to the chemokine at 20 ng/mL. Response to MCP-1 was already detectable at 1 pg/mL, whereas at least 5 ng/mL were required for significant chemotactic response. The kinetics of the increase in [Ca2+]i were considerably different for MCP-1 compared with f-MLP. MCP-1 produced a slow increase of [Ca2+]i that reached a plateau in 5 to 7 minutes. On the other hand, the increase of [Ca2+]i induced by f-MLP appeared to be biphasic, with a fast phase peaking after 5 to 40 seconds followed by a slower wave. Blocking of Ca2+ channels by Ni2+ or Cd2+ and/or chelation of extracellular free Ca2+ considerably reduced but did not abolish response to MCP-1, had no effect on the first wave of [Ca2+]i induced by f-MLP, and completely abrogated the second, slower wave. Thapsigargin, which empties intracellular Ca2+ stores, inhibited f-MLP-induced [Ca2+]i increase but fully blocked the action of MCP-1 only when combined with Ni2+. Thus, increase of [Ca2+]i induced by MCP-1 is apparently due to independent opening of a channel and mobilization from intracellular stores, whereas f-MLP-induced mobilization of Ca2+ from stores causes subsequent opening of a channel. At variance with MCP-1, the related chemokine MCP-2 induced only a low increase of [Ca2+]i in about 40% of adherent monocytes. Inhibition of chemokine-induced increase of [Ca2+]i by cholera or pertussis toxin indicated that MCP-1 and MCP-2 activate monocytes through different intracellular pathways. These results demonstrate at the single-cell level that the mechanisms and dynamics of increased [Ca2+]i are considerably different for f-MLP and chemokines beta. In addition, the [Ca2+]i increase induced by the two related chemokines beta MCP-1 and MCP-2 appears to be differently regulated, suggesting interaction with distinct receptors.

Ureteral lithiasis: in situ piezoelectric versus in situ spark gap lithotripsy. A randomized study

OBJECTIVES

In situ extracorporeal lithotripsy (EL) is the treatment of choice for ureteral lithiasis at our institution since the introduction of the painless lithotripters in clinical practice. The major objections to such clinical approach are: difficult ultrasound localization of ureteral calculi (if an ultrasound-guided lithotripter is used); lower energy of the painless piezoelectric compared to the spark gap system. To evaluate the efficacy of in situ EL of ureteral stones and to compare two different lithotripters (the spark gap fluoroscopically-guided Dornier HM3 versus the piezoelectric ultrasound-guided Wolf Piezolith 2300), we conducted a prospective randomized study.

METHODS

70 patients were randomly divided into two groups according to the following inclusion criteria: radiopaque stones of lumbar or prevesical tract (iliac and pelvic stones were excluded); stones with largest diameter not more than 2 cm.

RESULTS AND CONCLUSION

The evaluation of the treatment was done by plain film (KUB) at 24 and 72 hrs and by ultrasound at 48 hrs to assess stone fragmentation using migration of the fragments more distally into the ureter as criteria for success. The results were comparable: 76.6% for extracorporeal piezoelectric lithotripsy (EPL) and 74% for extracorporeal shock wave lithotripsy (ESWL). Better results were observed in both groups for the prevesical stones. The focussing time required was also comparable.

Identification of MIP-1 alpha/LD78 as a monocyte chemoattractant released by the HTLV-I-transformed cell line MT4

It is known that the HTLV-I-transformed cell line MT4 releases chemotactic activity for monocytes spontaneously. The MT4 monocyte chemoattractant was purified to homogeneity and sequencing of 25 amino acids revealed identity with the C-C chemokine macrophage inflammatory protein-1 alpha (MIP-1 alpha/LD78). An anti-MIP-1 alpha/LD78 rabbit antiserum substantially inhibited chemotaxis of the MT4 chemoattractant. MT4 cells constitutively expressed MIP-1 alpha/LD78 but not the C-C chemokines MCP-1, RANTES, and MIP-1 beta/Act2 and the C-X-C chemokines IL-8, gro alpha, and gro beta. MT4-derived MIP-1 alpha/LD78 was active on monocytes but was a weak chemoattractant for polymorphonuclear leukocytes. Thus, MIP-1 alpha/LD78 is a major monocyte chemoattractant released by HTLV-I-transformed T cells. Expression of MIP-1 alpha/LD78, a leukocyte chemotactic and myelosuppressive molecule, may play an important role in the manifestations of HTLV-I-related diseases.

The pneumotoxicant paraquat induces IL-8 mRNA in human mononuclear cells and pulmonary epithelial cells

Paraquat (PQ) is a herbicide which is highly pneumotoxic by generating reactive oxygen intermediates (ROI). Pro-inflammatory cytokines, particularly IL-1 and TNF, have been implicated in some ROI-mediated pathologies, including bleomycin toxicity and ischaemia/reperfusion injury. We have studied the effect of PQ on the expression of the neutrophil chemotactic cytokine, IL-8, by human peripheral blood mononuclear cells (PBMC). While almost no IL-8 mRNA was detected in unstimulated cells, PQ (100 microM) induced high mRNA expression with a maximum at 24 h of incubation. While PQ did stimulate the appearance of IL-8 mRNA, no significant production of IL-8 protein was detected. However, PQ potentiated the production of IL-8 in the presence of 1 ng/ml of endotoxin (lipopolysaccharide, LPS). This was paralleled by an increased production of chemotactic activity for neutrophils, indicating that the IL-8 was actually bioactive. Stimulation of IL-8 mRNA by PQ was suppressed by IL-4 and by free radical scavengers (dimethylsulfoxide, mannitol). Increased IL-8 expression by PQ was also observed in the human pulmonary epithelial cell line A549 indicating that the effect of PQ was not specific for PBMC. These findings suggest that IL-8 might be involved in the pulmonary effects of PQ and that its production might be stimulated following an oxidative insult, and might clarify the pathogenetic mechanisms of adult respiratory distress syndrome (ARDS) or oxidant-induced pulmonary fibrosis.