Showing papers by "Achille P. Caputi published in 2002"
TL;DR: The hypothesis that superoxide anions play an important role in gentamicin-mediated nephropathy is confirmed and the possible clinical use of low molecular weight synthetic superoxide dismutase mimetics in those conditions that are associated with over production of superoxide is supported.
265 citations
TL;DR: Genistein therapy improves flow-mediated endothelium dependent vasodilation in healthy postmenopausal women and may be mediated by a direct effect of genistein on the vascular function and could be the result of an increased ratio of nitric oxide to endothelin.
231 citations
TL;DR: It is shown for the first time that prevention of the activation of NF‐κB by PDTC reduces the development of acute and chronic inflammation.
Abstract: The nuclear factor-κB (NF-κB) is a transcription factor which plays a pivotal role in the induction of genes involved in physiological processes as well as in the response to injury and inflammation. Dithiocarbamates are antioxidants which are potent inhibitors of NF-κB.
We postulated that pyrrolidine dithiocarbamate (PDTC) would attenuate inflammation. In the present study we investigate the effects of PDTC in animal models of acute and chronic inflammation (carrageenan-induced pleurisy and collagen-induced arthritis).
We report here for the first time that PDTC (given at 100, 30 or 10 mg kg−1 i.p. in the pleurisy model or at 10 mg kg−1 i.p. every 48 h in the arthritis model) exerts potent anti-inflammatory effects (e.g. significant reduction of (A) pleural exudate formation, (B) polymorphonuclear cell infiltration, (C) lipid peroxidation, (D) inducible nitric oxide synthase (iNOS) activity and nitric oxide production (E) plasma and pleural exudates levels of interleukin-1β and tumour necrosis factor-α, (F) histological injury and (G) delayed development of clinical indicators).
Furthermore, PDTC reduced immunohistochemical evidence of (A) formation of nitrotyrosine, (B) activation of poly (ADP-ribose) polymerase (PARP), (C) expression of iNOS and (D) expression of cyclo-oxygenase-2 (COX-2) in the lungs of carrageenan-treated mice and in the joints from collagen-treated mice.
Additionally, Western blotting and immunohistochemical analysis of lung tissue revealed that PDTC prevented degradation of IKB-α and translocation of NF-κB from the cytoplasm into the nucleus.
Taken together, our results clearly demonstrate that prevention of the activation of NF-κB by PDTC reduces the development of acute and chronic inflammation. Therefore, inhibition of NF-κB may represent a novel approach for the therapy of inflammation.
British Journal of Pharmacology (2002) 135, 496–510; doi:10.1038/sj.bjp.0704463
210 citations
TL;DR: It is reported for the first time, to the authors' knowledge, that 15d-PGJ(2) exerts potent anti-inflammatory effects in vivo and may be useful in the therapy of acute and chronic inflammation.
Abstract: Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors that are related to retinoid, steroid, and thyroid hormone receptors. The PPAR-gamma receptor subtype seems to play a pivotal role in the regulation of cellular proliferation and inflammation. Recent evidence also suggests that the cyclopentenone prostaglandin (PG) 15-deoxyDelta(12,14)-PGJ(2) (15d-PGJ(2)), which is a metabolite of prostaglandin D(2), functions as an endogenous ligand for PPAR-gamma. We postulated that 15d-PGJ(2) would attenuate inflammation. In the present study, we have investigated the effects of 15d-PGJ(2) of acute and chronic inflammation (carrageenan-induced pleurisy and collagen-induced arthritis, respectively) in animal models. We report for the first time, to our knowledge, that 15d-PGJ(2) (given at 10, 30, or 100 microg/kg i.p. in the pleurisy model or at 30 microg/kg i.p every 48 h in the arthritis model) exerts potent anti-inflammatory effects (e.g., inhibition of pleural exudate formation, mononuclear cell infiltration, delayed development of clinical indicators, and histological injury) in vivo. Furthermore, 15d-PGJ(2) reduced the increase in the staining (immunohistochemistry) for nitrotyrosine and poly (ADP-ribose) polymerase and the expression of inducible nitric-oxide synthase and cyclooxygenase-2 in the lungs of carrageenan-treated mice and in the joints from collagen-treated mice. Thus, 15d-PGJ(2) reduces the development of acute and chronic inflammation. Therefore, the cyclopentenone prostaglandin 15d-PGJ(2) may be useful in the therapy of acute and chronic inflammation.
124 citations
TL;DR: The results suggest that the induction of iNOS and NO production are essential for the upregulation of the inflammatory response in splanchnic ischemia/reperfusion and participate in end organ damage under these conditions.
Abstract: The aim of this study was to investigate the role of inducible nitric oxide (NO) synthase (iNOS) and NO on the modulation of the inflammatory response caused by splanchnic ischemia and reperfusion. A severe model of mesenteric ischemia and reperfusion was produced by subjecting mice to 45 min occlusion followed by reperfusion of the superior mesenteric artery and celiac trunk. In this experimental protocol, wild-type mice treated with GW274150 (5 mg/kg i.p.), a novel, potent, and selective inhibitor of iNOS activity, and mice lacking of the gene for iNOS (iNOS 'knock-out', iNOS-KO) exhibited no difference in the rate of mortality in comparison with wild-type control mice. In a second study, using a less severe model of mesenteric injury obtained by occlusion of the superior mesenteric artery only for 45 min, we evaluated the survival rate. Under these conditions, wild-type mice treated with GW274150 and iNOS-KO mice showed a significant difference in the rate of mortality in comparison with wild-type. Therefore, wild-type mice treated with GW274150 and iNOS-KO mice when compared with wild-type littermates showed a significant reduction of the mesenteric injury, upregulation of P-selectin and intercellular adhesion molecule-1, and neutrophil infiltration, as well as a significant inhibition of the degree of oxidative and nitrosative damage, indicated by malondialdehyde levels, formation of nitrotyrosine and poly(ADP-ribose)polymerase (PARP), respectively. Plasma levels of the proinflammatory cytokines tumour necrosis factor-alpha, interleukin (IL) 6, and IL-1beta were also significantly reduced in iNOS-KO mice in comparison with control wild-type mice. Wild-type mice treated with GW274150 and iNOS-KO mice were also found to have reduced activation of the transcriptional factor nuclear factor-kappaB in the ileum. These results suggest that the induction of iNOS and NO production are essential for the upregulation of the inflammatory response in splanchnic ischemia/reperfusion and participate in end organ damage under these conditions.
111 citations
TL;DR: Treatment with recombinant human erythropoietin significantly reduced delayed neuronal death in the CA1 area of the hippocampus and prevented cognition impairment in the passive avoidance test, indicating that neuroprotective effects in brain ischemia are associated with the preservation of learning function.
92 citations
TL;DR: Findings provide the first evidence that the activation of PARS participates in neutrophil-mediated lung injury by regulating the expression of P-selectin and ICAM-1.
71 citations
TL;DR: It is provided the first evidence that GW274150, a novel, potent and selective inhibitor of iNOS activity, attenuates the degree of chronic inflammation and tissue damage associated with collagen-induced arthritis in mice.
68 citations
TL;DR: Within the series of chiral 3,3'-(1,2-ethanediyl)bis[2-arylthiazolidin-4-ones], the 3,4-dimethoxyphenyl substituted derivative was found in the primary anti-inflammatory screening to be endowed with superior in vivo properties and good safety profile.
63 citations
TL;DR: These data suggest that IRFI 042 blocks the activation of NF-kappaB, reduces TNF-alpha mRNA levels, and finally reverses endotoxic shock.
Abstract: Background: The aim of our study was to investigate the effect of IRFI 042, a novel dual vitamin E-like antioxidant, on nuclear factor-κB (NF-κB) activation, TNF-α gene priming and on the release of the mature protein during endotoxin shock. Methods: Endotoxin shock was produced in male rats by a single intravenous (i.v.) injection of 20 mg kg−1 of Salmonella enteritidis lipopolysaccharide (LPS). Survival rate, mean arterial blood pressure, serum TNF-α and plasma malondialdehyde (MAL) levels were investigated. We then evaluated in the liver TNF-α mRNA levels, NF-κB binding activity and the inhibitory protein IκBα. Moreover we studied in LPS stimulated (50 μg ml−1) peritoneal macrophages (Mφ), NF-κB activation, cytoplasmic IκB-α degradation, the message for TNF-α, and TNF-α and MAL levels. Results: LPS administration reduced survival rate (0%, 72 h after LPS administration), decreased mean arterial blood pressure, augmented serum TNF-α (60±11 ng ml−1) and enhanced plasma malondialdehyde (MAL) levels (55±7.1 nmol l−1). LPS shocked rats also had increased TNF-α mRNA levels, augmented liver NF-κB binding activity in the nucleus and decreased levels of the inhibitory protein IκBα. In addition, in vitro LPS stimulation (50 μg ml−1) significantly induced NF-κB activation and cytoplasmic IκBα degradation in Mφ, enhanced TNF-α mRNA levels and increased Mφ TNF-α and MAL. Treatment with IRFI 042 (20 mg kg−1, i.v., 5 min after endotoxin challenge) protected against LPS-induced lethality (90% survival rate 24 h and 80% survival rate 72 h after LPS injection, respectively), reduced hypotension, blunted plasma MAL (9.0±0.9 nmol l−1) and decreased serum TNF-α (15±3 ng ml−1). The antioxidant also inhibited the loss of IκBα protein from the hepatic cytoplasm, blunted the increased NF-κB binding activity in the liver and decreased hepatic liver mRNA for TNF-α. Furthermore ‘in vitro’ IRFI 042 (50 μM) significantly inhibited activation of NF-κB through inhibition of IκBα degradation, reduced the amount of TNF-α mRNA, decreased LPS-induced TNF-α release and blunted lipid peroxidation (MAL) in LPS stimulated Mφ. Conclusions: These data suggest that IRFI 042 blocks the activation of NF-κB, reduces TNF-α mRNA levels, and finally reverses endotoxic shock.
55 citations
TL;DR: Results clearly confirmed that COX-2 plays a critical role in the development of theinflammatory response by altering key components of the inflammatory cascade and offers a therapeutic approach for the management of various inflammatory diseases.
TL;DR: Data demonstrate that endogenous IL-6 exerts an anti-inflammatory role during acute pancreatitis, possibly by regulating the expression of adhesion molecules, the subsequent adhesion and activation of neutrophils and finally the generation of cytokine and reactive oxygen or nitrogen species.
TL;DR: It is suggested that the absence of IL-10 may represent an important pathophysiological mechanism of hepatobiliary injuries and cholestasis observed in patients with IBD.
Abstract: A variety of hepatobiliary abnormalities have been described in patients with chronic inflammatory bowel diseases (IBDs) The purpose of this study was to investigate the role of endogenous IL-10 in alteration of hepatocyte TJ paracellular barrier and in the rapid transcytotic vesicular pathway modification associated with intestinal inflammation To address this question, we used an experimental model of colitis, induced by dinitrobenzene sulfonic acid (DNBS) When compared to DNBS-treated IL-10 wild-type (IL-10WT) mice, DNBS-treated IL-10 knock-out mice (IL-10KO) mice experienced a higher rate of the extent and severity of the histological signs of colon injury Colon and liver levels of the pro-inflammatory cytokines tumour necrosis factor, interleukin-1β and interleukin-6 were also greatly enhanced in IL-10KO mice in comparison to wild-type mice Liver histology from IL-10KO and IL-10WT did not show any parenchymal and portal tract inflammation at 4 days after DNBS administration Serum total bilirubin and Alanine aminotransferase, were significantly increased in DNBS-IL-10KO mice vs DNBS-IL-10KO mice Therefore, we found an increase of tight junctional permeability to lanthanum nitrate (molecular weight, 433) in the livers from DNBS-treated IL-10WT mice; lanthanum accumulated throughout the junctional area up to the most apical region bordering the lumen Absence of a functional IL-10 gene in IL-10KO mice resulted in a significant augmentation of apical diffusion of lanthanum after DNBS-induced colitis Immunofluorescent labelling of frozen liver sections from DNBS-IL10KO mice, immunolocalization for and claudin-1 and ZO-1 resulted in a significant alteration in the localization of the immunosignals for claudin-1 and ZO-1 after DNBS administration in comparison with DNBS-IL10WT In conclusion, we suggest that the absence of IL-10 may represent an important pathophysiological mechanism of hepatobiliary injuries and cholestasis observed in patients with IBD
TL;DR: The aim of the present study was to investigate the effects of GPI 6150, a new poly(ADP-ribose) polymerase (PARP) inhibitor, in the pathogenesis of splanchnic artery occlusion (SAO) shock in rats.
Abstract: The aim of the present study was to investigate the effects of GPI 6150, a new poly(ADP-ribose) polymerase (PARP) inhibitor, in the pathogenesis of splanchnic artery occlusion (SAO) shock. SAO shock was induced in rats by clamping both the superior mesenteric artery and the celiac trunk for
TL;DR: GPI 6150 significantly reduced the degree of hemorrhagic diarrhea and weight loss caused by administration of dinitrobenzensulfonic acid, and it is proposed that GPI6150 may be useful in the treatment of inflammatory bowel disease.
Journal Article•
TL;DR: It is demonstrated that endogenous IL-10 exerts an anti-inflammatory role during chronic inflammation and tissue damage associated with collagen-induced arthritis, possibly by regulating neutrophil recruitment, and the subsequent cytokine and oxidant generation.
Abstract: Interleukin-10 (IL-10) exerts a wide spectrum of regulatory activities in the immune and inflammatory response. The aim of this study was to investigate the role of endogenous IL-10 in the modulation of the inflammatory response in mice subjected to collagen-induced arthritis. Collagen-induced arthritis (CIA) was induced in mice lacking the gene for IL-10 (IL-10 "knock-out", IL-10KO) and in wild-type control (IL-10WT) mice by an intradermal injection of 100 mul of the emulsion (containing 100 mug of bovine type II collagen) (CII) and complete Freund's adjuvant (CFA) at the base of the tail. On day 21, a second injection of CII in CFA was administered. IL-10 wild type (WT) mice developed an erosive, hind paw arthritis when immunised with CII in CFA. Macroscopic clinical evidence of CIA first appeared as peri-articular erythema and oedema in the hind paws. The incidence of CIA was 100% by day 27 in the CII-challenged IL-10WT. The severity of CIA progressed over a 35-day period, with radiographic evaluation revealing focal resorption of bone. The histopathology of CIA included erosion of the cartilage at the joint margins. IL-10KO mice experienced higher rates of clinical signs and more severe knee and paw injury as compared to IL-10WT. The degree of oxidative and nitrosative damage was significantly higher in IL-10KO mice than in wild-type littermates, as indicated by elevated malondialdehyde levels and formation of nitrotyrosine and poly (ADP-ribose) synthetase (PARS). Plasma levels of the proinflammatory cytokines, tumour necrosis factor, interleukin-1beta and interleukin-6 were also greatly enhanced in comparison to wild-type mice. These data demonstrate that endogenous IL-10 exerts an anti-inflammatory role during chronic inflammation and tissue damage associated with collagen-induced arthritis, possibly by regulating neutrophil recruitment, and the subsequent cytokine and oxidant generation.
TL;DR: Activation of PARS by exogenous and endogenous peroxynitrite may be involved in the tight junction derangement associated with endothelial dysfunction and inhibition of Pars may be a novel pharmacological approach to preserve endothelial tight junction function in shock and inflammation.
Abstract: DNA single-strand breakage and activation of the nuclear enzyme poly(ADP-ribose) synthetase (PARS) triggers an energy consuming, inefficient repair cycle, which contributes to peroxynitrite-induced cellular injury. Here, we investigated whether peroxynitrite and PARS activation are involved in tight junctions (tight junction) derangement in the endothelial dysfunction in cells exposed to peroxynitrite and in vascular rings of animals subjected to zymosan non-septic shock. In human umbilical vein endothelial cells (HUVEC) in vitro, peroxynitrite caused a dose-dependent suppression of mitochondrial respiration, as measured by the mitochondrial-dependent conversion of the dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide to formazan. Moreover, peroxynitrite caused activation of PARS. Inhibition of PARS by 3-aminobenzamide (3-AB; 1 mM) reduced the peroxynitrite-induced suppression of mitochondrial respiration in HUVECs. Vascular rings exposed to peroxynitrite exhibited reduced endothelium-dependent relaxant responses in response to acetylcholine. Peroxynitrite incubation also caused a significant derangement of zonula occludens (ZO)-1, which was significantly affected by pharmacological inhibition of PARS. 3-AB ameliorated the development of this peroxynitrite-induced endothelial dysfunction. In vascular rings obtained from the zymosan-treated rats, there was a marked suppression of the endothelium-dependent relaxation ex vivo, which was reduced by in vivo 3-AB treatment. A significant derangement of ZO-1 was observed in vascular rings from zymosan-treated rats. Tight junction alteration was significantly reduced by in vivo 3-AB treatment. Thus, activation of PARS by exogenous and endogenous peroxynitrite may be involved in the tight junction derangement associated with endothelial dysfunction. Inhibition of PARS may be a novel pharmacological approach to preserve endothelial tight junction function in shock and inflammation.
TL;DR: The data suggest that soy isoflavones produce an improvement of endothelial dysfunction induced by ovariectomy so as 17beta-estradiol, but probably without changes in reproductive system.
Abstract: Effects of oral administration for 4 weeks of a soy fraction with mainly isoflavones (Glycine max, Leguminosae) (SOYPH; 5 mg/kg) on vascular dysfunction induced by bilateral ovariectomy (OVX) in rats were studied. We evaluated vascular reactivity of aortic rings after acetylcholine (ACh 10 nM-10 microM), sodium nitroprussiate (SN 15 - 30 nM) and NG-L-arginine (L-NMA; 10 - 100 microM). Uterine weight and nitric oxide synthase (NOS) activity were also investigated. The same parameters were observed after 4 weeks treatment with 17beta-estradiol. In OVX rats endothelial-dependent vascular responses were changed: reduction of induced contraction ( L-NMA 100 mM: sham OVX 2.1 +/- 0.2 g/mg tissue; OVX 1.7 +/- 0.4 g/mg tissue). Ovariectomy produced a reduction of constitutive NOS activity. Uterine weight was increased in animals treated with 17beta-estradiol but not with SOYPH. Either SOYPH or 17beta-estradiol produced a similar improvement of endothelial dysfunction and increased NOS activity. Our data suggest that soy isoflavones produce an improvement of endothelial dysfunction induced by ovariectomy so as 17beta-estradiol, but probably without changes in reproductive system.
TL;DR: This study provides the first evidence that the protein kinase inhibitor tyrphostin AG 126 attenuates the degree of MOF associated with zymosan-induced peritonitis in the rat.
Abstract: Objective. To investigate the effects of tyrphostin AG 126, a tyrosine kinase inhibitor, on the multiple organ failure (MOF) caused by zymosan in the rat.
Journal Article•
TL;DR: The results clearly demonstrate that endogenous IL-10 exerts an anti-inflammatory role during acute inflammation and tissue damage associated with carrageenan-induced pleurisy, possibly by regulating neutrophil recruitment, and the subsequent cytokine and oxidant generation.
Abstract: ABBREVIATIONS NO: nitric oxide NOS: nitric oxide synthase ecNOS: constitutive endothelial nitric oxide synthase iNOS: inducible nitric oxide synthase PARS: poly (ADP-ribose) synthetase MPO: myeloperoxidase PMN: polymorphonuclear cell PBS: phosphate-buffered saline INTRODUCTION The balance between pro-inflammatory and other processes that serve to down regulate the inflammation [...]
TL;DR: It is suggested that acute blood loss causes activation of NF-κB and that tacrolimus, by inhibiting this transcription factor, protects against acute hypovolemic shock.
TL;DR: This study provides the first evidence that calpain inhibitor I attenuates the degree of zymosan-induced multiple organ failure in the rat.
Abstract: Objective Zymosan enhances the formation of reactive oxygen species, which contributes to the pathophysiology of multiple organ failure. We investigated the effects of calpain inhibitor I (5, 10, or 20 mg/kg) on the multiple organ failure caused by zymosan (500 mg/kg, administered intraperitoneally as a suspension in saline) in rats. Setting University research laboratory. Subjects Male Sprague-Dawley rats. Interventions Multiple organ failure in rats was assessed 18 hrs after administration of zymosan and/or calpain inhibitor I and was monitored for 12 days (for loss of body weight and mortality rate). Measurement and Main Results Treatment of rats with calpain inhibitor I (5, 10, or 20 mg/kg intraperitoneally, 1 and 6 hrs after zymosan) attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan in a dose-dependent fashion. Calpain inhibitor I also attenuated the lung, liver, and intestinal injury (histology) as well as the increase in myeloperoxidase activity and malondialdehyde concentrations caused by zymosan in the lung, liver, and intestine. Immunohistochemical analysis for nitrotyrosine and for poly(adenosine-disphosphate-ribose) revealed positive staining in lung, liver, and intestine from zymosan-treated rats. The degree of staining for nitrotyrosine and poly(adenosine-disphosphate-ribose) was reduced markedly in tissue sections obtained from zymosan-treated rats administered calpain inhibitor I (20 mg/kg intraperitoneally). Furthermore, treatment of rats with calpain inhibitor I significantly reduced the expression of inducible nitric oxide synthase and cyclooxygenase-2 in lung, liver, and intestine. Conclusion This study provides the first evidence that calpain inhibitor I attenuates the degree of zymosan-induced multiple organ failure in the rat.
TL;DR: Data demonstrate that endogenous IL-6 exerts an anti-inflammatory role during acute pancreatitis, possibly by regulating the expression of adhesion molecules, the subsequent adhesion and activation of neutrophils and finally the generation of cytokine and reactive oxygen or nitrogen species.
Abstract: Interleukin-6 (IL-6) exerts a wide spectrum of regulatory activities during immune and inflammatory responses. The aim of this study was to investigate the role of endogenous IL-6 in the inflammatory response associated with acute pancreatitis. Acute pancreatitis was induced by hourly (x5) i.p. injections of cerulein (50 microg/kg, suspended in saline solution) in IL-6 deficient mice (IL-6-KO) and wild-type (IL-6WT) littermates. IL-6KO mice exhibited a more severe tissue injury and a higher rate of mortality and when compared to IL-6WT mice. Acute pancreatitis was characterized by edema, neutrophil infiltration, tissue hemorrhage and cell necrosis, upregulation of P-selectin and intercellular adhesion molecule-1 (ICAM-1), as well as increases in the serum levels of amylase and lipase. The degree of oxidative and nitrosative tissue damage was significantly greater in IL-6KO mice than in wild-type littermates, as indicated by higher tissue levels of malondialdehyde and nitrosylated proteins. Plasma levels of the inflammatory cytokines tumour necrosis factor-alpha and interleukin-1beta were also greatly enhanced in IL-6KO mice when compared to wild-type mice. These events were correlated with an increase in the staining (immunoreactivity) for poly (ADP-ribose) polymerase (PARP) in the pancreas of cerulein-treated IL-6WT. The staining for PARP was more pronounced in IL-6KO mice subjected to acute pancreatitis than in the corresponding WT mice. These data demonstrate that endogenous IL-6 exerts an anti-inflammatory role during acute pancreatitis, possibly by regulating the expression of adhesion molecules, the subsequent adhesion and activation of neutrophils and finally the generation of cytokine and reactive oxygen or nitrogen species.
TL;DR: The lack of adherence to clinical guidelines and the marked variability of antibiotic prescription rates between different areas of the country appear to be related to factors other than bacterial resistance, and highlight the importance of carrying out educational programmes targeted at the national level for improving the antibiotic prescription habits for the treatment of RTIs.
TL;DR: In vitro stability studies of the conjugates indicated that they did not degrade rapidly into AD6 in the culture medium, suggesting that the observed effects can be ascribed to the conjUGates themselves, and not to the cloricromene released after their hydrolytic degradation.
Abstract: Lipophilic amide conjugates of cloricromene (AD6) with alkylamino acids were designed in order to improve their central nervous system efficacy and to obtain more stable molecules in the bloodstream. In vivo effects on mean arterial blood pressure (MAP) and tumor necrosis factor (TNF)-α plasma levels in Sprague-Dawley rats subjected to endotoxic shock, induced by administration of Escherichia coli lipopolysaccharides (LPS) along with AD6 or its amide conjugates, were evaluated to assess whether the modification of the drug's carboxylic moiety through an amide bond would affect its pharmacological activity. LPS (4 mg kg−1 iv) elicited a time-dependent decrease in MAP. Administration of AD6 conjugates 1 h prior to LPS delayed the development of late-phase hypotension. LPS-induced increases in TNF-α plasma levels were also inhibited by the tested conjugates, with efficacies close to that of free AD6. In vitro stability studies of the conjugates indicated that they did not degrade rapidly into AD6 in the culture medium, suggesting that the observed effects can be ascribed to the conjugates themselves, and not to the cloricromene released after their hydrolytic degradation. Drug Dev. Res. 57:115–121, © 2002 Wiley-Liss, Inc.