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International audience; Objectives - Time to blood culture positivity (TTP), a routinely available parameter in automated blood culture systems, may be a proxy for infectious burden in patients with bloodstream infections. We aimed to study the association between TTP and infective endocarditis (IE), or death, in patients with Staphylococcus aureus bacteraemia. Methods - VIRSTA is a multicenter prospective cohort study that included all adult patients with S. aureus bacteraemia in eight university hospitals in France (2009-2011). We analyzed data from four centers which collected data on TTP. Regression models were used to study the association between TTP and definite IE (Duke-Li criteria), and 30 day-mortality. Results - We included 587 patients with S. aureus bacteraemia: mean age was 65.3±16.3 years, 420/587 patients (71.6%) were male, 121/587 (20.6%) died, and 42/587 (7.2%) had definite IE. Median TTP of first positive blood culture was 13.7 h (interquartile range, 9.9-18). On multivariate analysis, 30-day mortality was associated with TTP≤13.7 h (74/295 (25.1%) vs 47/292 (16.1%), P=0.02), as well as old age, McCabe score, methicillin resistance, stroke, pneumonia, and C-Reactive Protein. TTP was also independently associated with IE, but with a U-shape curve: IE was more common in the first (TTP18 h, 8/146, 5.5%) quartiles of TTP, P=0.002. Conclusions - TTP provides reliable information in patients with S. aureus bacteraemia, on the risk of IE, and prognosis, with short TTP being an independent predictor of death. This data readily available at no cost may be used to identify patients who require specific attention.

OBJECTIVE: To assess the effectiveness of corticosteroids on outcomes of patients with COVID-19 pneumonia requiring oxygen without mechanical ventilation. METHODS: We used routine care data from 51 hospitals in France and Luxembourg to assess the effectiveness of corticosteroids at 0.8 mg/kg/day eq. prednisone (CTC group) versus standard of care (no-CTC group) among adults 18 to 80 years old with confirmed COVID-19 pneumonia requiring oxygen without mechanical ventilation. The primary outcome was intubation or death by day 28. In our main analysis, characteristics of patients at baseline (i.e., time when patients met all inclusion criteria) were balanced by using propensity-score inverse probability of treatment weighting. RESULTS: Among the 891 patients included in the analysis, 203 were assigned to the CTC group. Use of corticosteroids was not significantly associated with risk of intubation or death by day 28 (weighted hazard ratio [wHR] 0.92, 95% CI 0.61 to 1.39) or cumulative death rate (wHR 1.03, 95% CI 0.54 to 1.98). However, use of corticosteroids was associated with reduced risk of intubation or death by day 28 in the prespecified subgroups of patients requiring oxygen ≥ 3 L/min (wHR 0.50, 95% CI 0.30 to 0.85) or C-reactive protein level ≥ 100 mg/L (wHR 0.44, 95%CI 0.23 to 0.85). Number of hyperglycaemia events was higher for patients with than without corticosteroids, but number of infections was similar. CONCLUSIONS: We found no association between the use of corticosteroids and intubation or death in the broad population of patients 18 to 80 years old with COVID-19 hospitalized in non-intensive care unit settings. However, the treatment was associated with reduced risk of intubation or death for patients with ≥ 3 L/min oxygen or C-reactive protein level ≥ 100 mg/L at baseline. Further research need to confirm the right timing of corticosteroids for patients with COVID-19 requiring oxygen only.

We describe four SARS-CoV-2 re-infections with a B.1.351 variant in 2021, in healthcare workers (HCWs) previously infected in 2020, before detection of this variant in Europe. Cases live in France, near the border with Luxembourg, where variants B.1.351 and B.1.1.7 circulated. All work in the same hospital unit where a cluster of COVID 19 with B1.351 variant occurred, affecting patients and HCWs. Before the cluster onset, HCWs used surgical masks, as per recommendations. After cluster onset, HCWs used FFP2 masks.

International audience; Among 143 patients of the VIRSTA cohort study with Staphylococcus aureus bacteremia and an arthroplasty implanted for more than a year, S. aureus periprosthetic joint infection was observed in 19%. Signs of infection (pain and swelling) were always present, in median 1 day (range, 0-21 days) after onset of bacteremia. Staphylococcus aureus has both a high potential for metastatic infection and a high affinity for foreign material. Possible prosthesis infection is of clinical concern in all patients with preexisting prosthetic materials experiencing S. aureus bloodstream infection (SAB). Prosthetic joints are especially prone to infection during the course of bacteremia, with a risk of infection much higher with S. aureus than with other microorganisms, 20% vs 7%, in a recent prospective study [1]. As early intervention with debridement in prosthetic joint infection (PJI) is paramount to retain the implant and to prevent infection relapse; eliminating PJI after SAB is important. However, additional data are needed to better describe the clinical characteristics of PJI after SAB in particular time lapses and whether systematic imaging of the prosthesis could be necessary after SAB. We described the frequency and clinical presentation of PJIs observed among patients with prosthetic joints implanted for >1 year before bacteremia and enrolled in the VIRSTA study, a multicenter prospective cohort study of patients with SAB.

This chapter examines the potential involvement of platelet-activating factor (PAF) in shock by a “probability matrix”. The production of tumor necrosis factor by human platelet-free monocytes, isolated by counterflow elutriation, was analyzed following stimulation with endotoxin in the absence or presence of graded concentration ranges of PAF. The finding of increased levels of PAF in endotoxemia suggested that PAF antagonists may be effective in counteracting this pathology. Gastrointestinal hemorrhage is feature associated with septic shock, a condition which can also be produced in several species by injection of PAF or bacterial endotoxin. The chapter investigates the mediatory role of PAF in intestinal inflammation and ulceration. Using the rat model of colitis, the effects of treatment with BN 52021 in comparison with WEB 2086 and WEB 2170 were studied in endotoxin-induced ulceration by measuring PAF biosynthesis and changes in vascular permeability.

International audience; Staphylococcus aureus bacteraemia (SAB) is a frequent and deadly disease. Given the lack of a randomized trial, optimal first-line antibiotic treatment is still debated. Our aim was to identify prognostic factors in SAB patients and to analyse the impact of first-line antibiotics. The VIRSTA prospective cohort study was conducted in eight tertiary care centres in France. Consecutive incident adults in whom a blood culture drawn in participating centres grew S. aureus between April 2009 and October 2011 were prospectively followed for 12 weeks. Factors associated with 12-week case-fatality were identified by multivariate logistic regression. We enrolled 2091 patients and analysed survival in 1972 (median age 67.8 years, interquartile range 55.5–78.9; females 692/1972, 35.1%). SAB was nosocomial or healthcare-related in 1372/1972 (69.6%) of cases and the primary focus was unknown in 414/1972 (21.0%) of cases. Week 12 case-fatality rate was 671/1972 (34.0%). The main independent prognostic factors on multivariate analysis were age (adjusted OR by 10-year increment 1.56; 95% CI 1.44–1.69), septic shock (OR 5.11; 95% CI 3.84–6.80), metastatic cancer (OR 4.28; 95% CI 2.88–6.38), and unknown primary focus (OR 2.62; 95% CI 2.02–3.41). In the 1538 patients with methicillin-sensitive S. aureus (MSSA) bacteraemia, first-line empiric antistaphylococcal penicillins (OR 0.40; 95% CI 0.17–0.95) and vancomycin (OR 0.37; 95% CI 0.17–0.83), alone or combined with an aminoglycoside, were associated with better outcome compared with other antibiotics. There are few modifiable prognostic factors for SAB. Initiating empiric antibiotics with antistaphylococcal penicillins or vancomycin may be associated with better outcome in MSSA bacteraemia. © 2016 European Society of Clinical Microbiology and Infectious Diseases

A 20-year-old man presented with subacute dysarthria, along with bilateral facial and brachial palsy, after a febrile odynophagia. Initially brisk, his upper limb deep tendon reflexes decreased with muscle wasting concerning the C5-T1 myotomes. MRI showed bilateral prefrontal gyri and thalami lesions with anterior cervical spinal cord lesion (figures 1 and 2). Upper limb lower motor neuron involvement was confirmed by EMG. CSF analysis showed lymphocytic pleiocytosis, elevated protein, and normal glucose levels . Epstein-Barr virus (EBV) serology revealed acute infection with the presence of viral capsid antigen (VCA) immunoglobulin M and VCA immunoglobulin G (IgG), in the absence of Epstein-Barr nuclear antigen–1 IgG. EBV DNA load was increased in blood and CSF. Other investigations including HIV screening remained negative. Simultaneous upper and lower motor neuron injury, well-described in HIV, is an unusual finding in EBV infection.1

Introduction L’implantation de prothese articulaire est un acte chirurgical frequent, a risque d’infections primitives acquises durant la chirurgie et d’infections hematogenes secondaires a une bacteriemie liee a un autre foyer d’infection. Staphylococcus aureus est un des principaux agents responsable de bacteriemie mais aussi d’infection hematogene de prothese. L’objectif de cette etude etait de determiner l’incidence, le delai de survenue et les facteurs de risque des infections hematogenes de prothese articulaire apres une bacteriemie a S . aureus . Materiels et methodes Nous avons extrait les donnees de la cohorte prospective VIRSTA (diagnostic de bacteriemie a S . aureus entre le 1 er avril 2009 et le 31 octobre 2011) des patients de notre centre participant deja porteurs de prothese articulaire, en place depuis au moins un an, lors de la bacteriemie. Nous avons collecte les informations complementaires sur les protheses. Un suivi prolonge des patients a ete realise, standardise a 12 semaines apres la bacteriemie dans le cadre de l’etude VIRSTA et non standardise par la suite (consultation ou appel telephonique) afin de depister une infection hematogene de prothese. Resultats Trente-deux patients ont ete inclus, soit 48 protheses articulaires. Cinq patients (15,6 % ; IC 95 % [3,04 ; 28,21]) ont presente une infection hematogene de prothese articulaire (soit 10,4 % des protheses ; IC 95 % [1,77–19,06]). Tous avaient des manifestations cliniques locales precoces et la survenue de l’infection de prothese etait concomitante de la bacteriemie (delai maximal 1 jour apres la 1 re hemoculture positive). Aucune infection hematogene retardee n’a ete mise en evidence lors d’un suivi median de 17 mois. Dans notre travail, 2 facteurs de risque lies a la prothese ont ete identifies : une localisation de la prothese au genou ( p = 0,0012), un antecedent de reprise chirurgicale sur la prothese ( p = 0,0366) et 1 lie a l’hote : presence d’un diabete de type 2 ( p = 0,0342). La presence d’un rhumatisme inflammatoire et/ou la prise d’immunosuppresseurs et/ou le port de plusieurs protheses tend a etre associe statistiquement a une infection secondaire de prothese mais de facon non significative, probablement du fait du manque de puissance. Conclusion Le risque d’infection hematogene de prothese articulaire lors d’une bacteriemie a S . aureus est eleve et a une expression clinique precoce. Le risque d’infection retardee semble tres faible. Une surveillance clinique attentive dans les premieres semaines suivant la bacteriemie parait suffisante pour detecter ces infections.

Resume L’objectif de la Table Ronde etait d’aborder la Recherche Pre-competitive pour la premiere fois lors des Rencontres de Giens. Les participants venaient de l’industrie du medicament, des biotech, de l’industrie du dispositif, de l’academie, des services et societes de valorisation, des ministeres, du monde de la recherche clinique et fondamentale. Ils ont fait le constat des changements profonds dans la connaissance des maladies et dans le developpement des medicaments. A l’aide d’exemples dans le monde de la Sante et en dehors, ils ont identifie les principes, les enjeux, les facteurs de succes et de risque de la recherche precompetitive. Les particularites de la gestion de la propriete intellectuelle ont ete plus particulierement etudiees. La Table Ronde a conclu sur les principes de la recherche precompetitive en Sante, une revolution culturelle necessaire. C’est developper une recherche en partenariat fondee sur des principes nouveaux : i) comprendre et partager ; ii) integrer la complexite du vivant ; iii) agir dans l’interdisciplinarite.

Resume Nous decrivons la premiere observation de seminome primitif mediastinal revele par une metastase osseuse, sans tumeur testiculaire. Il s’agissait d’un homme de 24 ans qui se plaignait depuis six mois d’une douleur isolee de la hanche droite. Les radiographies et les examens biologiques etaient normaux. Nous avons mis en evidence une tumeur intra-thoracique asymptomatique dont la biopsie a l’aiguille a permis de porter le diagnostic de seminome. Pour la chimiotherapie, l’association etoposide-ifosfamide-cisplatine a ete choisie en raison de sa moindre toxicite et de la multiplicite des lesions. Les tumeurs germinales sont une etiologie rare de metastases osseuses qui doit neanmoins etre bien connue des rhumatologues, car leur pronostic est excellent lorsque le diagnostic et le traitement sont precoces. Nous proposons un commentaire sur les nouvelles methodes diagnostiques (tomodensitometrie [TDM], imagerie par resonance magnetique [IRM] et tomodensitometrie a emission de positons) et therapeutiques (chimiotherapie et radiotherapie).

Objective: To assess the effect of the lipidosterolic extract of Serenoa repens (LSESr) on in vitro cell proliferation in biopsies of human prostate Material and Methods: Cell proliferation was assessed by incorporation of [3H]thymidine followed by historadiography. Results: Basic fibroblast growth factor (b-FGF) induced a considerable increase in human prostate cell proliferation (from +100 to +250%); the glandular epithelium was mainly affected, minimal labeling being recorded in the other regions of the prostate. Similar results were observed with epidermal growth factor (EGF), although the increase in cell proliferation was not recorded in some cases. Lovastatin, an inhibitor of hydroxymethylglutaryl coenzyme A, antagonized both the basal proliferation and the growth factor-stimulated proliferation of human prostate epithelium (EGF, mean inhibition ≈80–95%; b-FGF, mean inhibition ≈40–90%). Geraniol, a precursor of both farnesyl pyrophosphate and geranylgeranyl pyrophosphate, and farnesol, the precursor of farnesyl pyrophosphate, increased cell proliferation only in some prostate specimens, this effect being antagonized by lovastatin. LSESr did not affect basal prostate cell proliferation, with the exception of two prostate specimens in which a significant inhibition of basal proliferation was observed with the highest concentration of LSESr (30 µg/ml). In contrast, LSESr inhibited b-FGF-induced proliferation of human prostate cell cultures; this effect was significant for the highest concentration of LSESr (30 µg/ml). In some prostate samples, a similar inhibition was also noted with lower concentrations. Unsaturated fatty acids (UFA), in the range 1–30 ng/ml, did not affect the basal prostate cell proliferation, only a slight increase in cell proliferation was noted in 1 prostate specimen. UFA (1, 10 or 30µg/ml) markedly inhibited the b-FGF-induced cell proliferation down to the basal value. Lupenone, hexacosanol and the unsaponified fraction of LSESr markedly inhibited the b-FGF-induced cell proliferation, whereas a minimal effect on basal cell proliferation was noted. Conclusions: Despite the large variability in the response of the prostate samples to b-FGF, these results indicate that LSESr and its components affect the proliferative response of prostate cells to b-FGF more than their basal proliferation.

The effect of the lipidosterolic extract of Serenoa repens (LSESR) on experimental prostate enlargement was investigated in three groups of rats: shams treated with LSESR (sham rats), castrated animals treated with estradiol and testosterone (castrated rats), castrated animals treated with estradiol/testosterone and treated with LSESR (castrated and treated rats). Following three months of continuous hormonal treatment, the weight of prostates in estradiol/testosterone-treated castrated rats was significantly increased in comparison with sham-operated rats. Such an increase started rapidly, reached a maximum by 30 days and remained at a plateau or slightly declined thereafter. The increase of prostate total weight induced by the hormone treatment was inhibited by administration of LSESR. Indeed, the weight was significantly lower at day 60 and day 90 for the dorsal and lateral regions of the prostate. The weight of the ventral region of the prostate was significantly lower after 30 and 60 days treatment with LSESR. These results demonstrate that administering LSESR to hormone-treated castrated rats inhibits the increase in prostate wet weight. This effect of LSESR may explain the beneficial effect of this extract in human benign prostatic hypertrophy.

The synthetic polyribonucleotide poly(A).poly(U) induces 2',5'-oligoadenylate synthetase activity in the murine macrophage cell line J774A1. The possible role of several cytokines involved in macrophage activation (i.e., IL-1, IL-6, TNF, and IFN) was examined in the present study. It was first demonstrated that among the anticytokine antibodies, only monoclonal antibodies directed against IL-6 inhibited the induction of 2',5'-oligoadenylate synthetase by poly(A).poly(U) in a dose-dependent manner. Moreover, it was established that poly(A).poly(U) elicited IL-6 production in J774A1 cells in a time-and dose-dependent manner. Consequently, the effect of IL-6 on 2',5'-oligoadenylate synthetase activity was studied. IL-6 either alone or in combination with IL-1 and TNF did not induce 2',5'-oligoadenylate synthetase activity. IL-6 did not potentiate IFN-gamma-induced 2'-5'-oligoadenylate synthetase activity. In contrast, addition of IL-6 to the incubation medium potentiated the stimulation of 2'-5'-oligoadenylate synthetase activity by IFN-alpha. These results suggest that IL-6 is a necessary but not sufficient factor in the induction of 2'-5'-oligoadenylate synthetase activity in the J774A1 cell line by poly(A).poly(U).

The great number of PAF antagonists reviewed in this article clearly shows the tremendous effort made in the last 20 yr to explore the complex biological background of the mechanism of action of PAF and the potential clinical benefit of its antagonists. It is obvious that now highly potent, long-acting, and perorally applicable PAF-receptor antagonists are developed, and available for preclinical and clinical research. Another important fact is that the progress in the biochemical research designed to explore the structure of PAF receptors is impressive. This work has been expected to answer numerous questions concerning the tissue specificity of several PAF antagonists. For example, among the synthetic hetrazepine PAF-receptor antagonists developed by the Beaufour-IPSEN group, BN 50727 exhibits higher efficacy in the gastrointestinal tract (67) than in other tissues; alternatively, BN 50730 exerts more potent effect in the lung (66) than in other organs. At the present state of knowledge, the interpretation of these differences is unclear. Better knowledge about the PAF-receptor structure in the gastrointestinal tract may shed more light on the background of drug-receptor interactions responsible for tissue specificity. This may lead to more successful clinical development of PAF receptor antagonists in the near future.

Oxygen-free radical toxicity is an important factor of tissue necrosis in the eye, especially in the retina. Activation of synthesis and release of platelet-activating factor (PAF) by ocular inflammatory cells and resident cells initiates cascades of mediators and cytokines which contribute to tissue damage in several ocular pathologies. The authors studied the therapeutic effectiveness of Ginkgo biloba extract (EGb 761), a potent free radical scavenger with anti-PAF activity, and of BN 50730, a specific PAF antagonist, on acute experimental autoimmune uveoretinitis induced in rats by S-antigen immunization. These treatments slightly delayed disease onset but had little effect on the severity of uveal inflammation. However, they significantly reduced inflammatory cell infiltration of the retina and the damage of the outer retinal layers. These drugs should become useful adjuvants in the therapy of posterior uveitis and other disorders that might damage the retina.

1 Platelet-activating factor (PAF) and leukotriene B4 (LTB4), two potent lipid mediators synthesized by activated neutrophils, are known to stimulate several neutrophil functional responses. In this study, we have determined that endogenous LTB4 and PAF exert autocrine effects on LT synthesis, as well as the underlying mechanism involved. 2 Pretreatment of neutrophils with either pertussis toxin (PT), or with receptor antagonists for LTB4 and PAF, resulted in an inhibition of LT synthesis induced by calcium ionophore, A23187. This inhibition was most marked at submaximal (100– 300 nm) A23187 concentrations, whilst it was least at ionophore concentrations which induce maximal LT synthesis (1–3 μm). Thus newly-synthesized PAF and LTB4 can enhance LT synthesis induced by A23187 under conditions where the LT-generating system is not fully activated. 3 In recombinant human (rh) granulocyte-macrophage colony-stimulating factor (GM-CSF)-primed neutrophils, LT synthesis in response to chemoattractants (fMet-Leu-Phe or rhC5a) was also significantly inhibited by the LTB4 receptor antagonist, and to a lesser extent by PAF receptor antagonists. 4 Further investigation revealed that LTB4 and/or PAF exert their effects on LT synthesis via an effect on arachidonic acid (AA) availability, as opposed to 5-lipoxygenase (5-LO) activation. Indeed, the receptor antagonists, as well as PT, inhibited LT synthesis and AA release to a similar extent, whereas 5-LO activation (assessed with an exogenous 5-LO substrate) was virtually unaffected under the same conditions. Accordingly, we showed that addition of exogenous LTB4 could enhance AA availability in response to chemoattractant challenge in rhGM-CSF-primed cells, without significantly affecting the 5-LO activation status. 5 Our data show that newly-generated PAF and LTB4 have the ability to positively feedback on LT synthesis by acting at the level of the phospholipase A2/re-esterification component of the LT biosynthetic pathway in neutrophils. Such autocrine affects are likely to represent an important amplification step of LT synthesis, and may as such contribute to the rapid onset, as well as to the evolution, of inflammatory responses.

This study investigated the distribution of platelet activating factor (PAF) binding sites in the brain and their involvement in global ischemia in a model of bilateral common carotid occlusion in the gerbil. In sagittal sections of gerbil brain, labeling with [3H]PAF was mainly located in the cortex, hippocampus and cerebellum. The corpus striatum, the superior and inferior colliculi showed lower binding, while the thalamus was only weakly labeled. Scatchard analysis of the data obtained from displacement curves with unlabeled PAF revealed the presence of one or two populations of binding sites with different affinity constant values depending on the brain structures. When the gerbils were submitted to 10 min ischemia, similar autoradiography with [3H]PAF demonstrated a dramatic reduction of labeling in all brain structures, particularly in the hippocampus. Immunoreactive endogenous PAF concentrations in brain tissues showed a marked increase in ischemic animals: (8977.3 +/- 1113 pg/g wet weight) as compared to sham-operated control: (997.7 +/- 77 pg/g wet weight). Endogenous PAF levels returned to basal values following 30 min reperfusion. These results indicate that PAF may be involved in the early stages of brain ischemia in the gerbil and suggest that endogenous PAF produced during ischemia may contribute to the down-regulation of [3H]PAF binding sites in the brain.

Myocardial ischemia assessed by intracavital ST-segment elevation, shortening of ventricular effective refractory period (VERP), and increase in left ventricular end-diastolic pressure (LVEDP) was provoked by ventricular overdrive pacing (VOP) in conscious rabbits. Cromakalim (10 micrograms/kg), an ATP-sensitive K+ channel opener, and cicletanine (30 mg/kg), a cGMP-phosphodiesterase inhibitor, reduced VOP-induced ST-segment elevation and LVEDP-increase. Under resting conditions, cromakalim lowered blood pressure, increased heart rate (HR), and shortened VERP, whereas cicletanine decreased HR, prolonged VERP without changing blood pressure. Co-administration of cromakalim and cicletanine additively reduced VOP-induced ST-segment elevation, shortening of VERP, and LVEDP-increase. Cicletanine did not change cromakalim-induced hypotension but abolished reflexogenic tachycardia. This suggests that VERP shortening is not a prerequisite for the anti-ischemic effect of cromakalim, and the combination of these drugs may afford a potent and safe anti-ischemic effect without affecting hypotension induced cromakalim.

The aim of the present study was to investigate the possible effect of platelet-activating factor (PAF), by comparison with interleukin-1β and polyriboinositic/polyribocytidylic (poly I–C) acid, on IL-6 production by L 929 mouse fibroblasts. At concentrations above 1 μM PAF, the production of IL-6 by mouse fibroblasts was enhanced in a dose dependent fashion. At 5 μM PAF, the peak increase (60.1 ± 19.4 U/ml) was similar to that induced by 50 μg/ml poly I–C (60.0 ± 35.0 U/ml) and higher than the one evoked by 100 U/ml IL-1β (3.8 ± 1.8 U/ml). The increase of 11-6 activity induced by 5 μM PAF was maximal after a 22 h incubation period with L 929 cells. Lyso-PAF (5 μM) also increased IL-6 activity from fibroblasts to a similar extent compared with 5 μM PAF. In addition, the IL-6 activity induced by 5 μM PAF was still observed when the specific PAF antagonist, BN 52021 (10 μM), was added to the incubation medium of L 929 cells. The result suggests that the production of IL-6 by L 929 cells evoked by PAFin vitrois not receptor mediated. Thein vivoeffect of PAF on IL-6 production was also investigated in the rat. Two hours after intravenous injection of PAF (2 to 4 μg/kg), a dramatic increase of IL-6 activity in rat serum was observed, this effect being dose dependent. The increase of IL-6 induced by 3 μg/kg PAF was not observed when the animals were treated with the PAF antagonist, BN 52021 (1 to 60 mg/kg0. These results demonstrate that PAF modulates IL-6 production and that thein vivoeffect is receptor mediated.

The present study examined the in vitro and in vivo effect of salbutamol on IgE production in the mouse. The present results show that salbutamol potentiates the in vitro interleukin 4 (IL-4)-induced

The thermodynamic ionization constants (pK(a)(1), pK(a)(2), and pK(a)(3)) of ginkgolide B (9H-1,7a-(epoxymethano)-1H,6aH-cyclopenta[c]furo[2,3-b]furo-[3',2':3,4]cyclopenta[1,2-d]furan-5,9,12-(4H)-trione, 3-tert-butylhexahydro-4,7b,11-trihydroxy-8-methyl-) in aqueous solution have been settled by pH-metric and NMR studies. The three macroscopic pK(a) values as well as the water solubility and the water/n-octanol partition coefficient have been extracted from pH-metric data by means of a nonlinear regression methodology. NMR spectroscopy provided confirmation of the values of the macroscopic constants, information about the effective ionization pathways, and an estimation of the proportions of the various forms under physiologically relevant conditions.

Endothelin (ET) is a peptide produced by the cells of the vascular endothel ium and is one of the most effective endogenous vasoconstrictive agents. The first reports on its isolation, purification, and synthesis appeared in 1987-88 [2]. In the interim it has been shown that in the mammalian organism at least three types of endothelin (ET-1, ET2, and ET-3) are synthesized, of which only ET1 is of endothelial origin. The vascular smooth muscles respond to ET-1 by a slowly developing strong contraction. ET-1 interacting with a receptor has been shown to cause, like other vasoconstrictors, activation of the phosphatidylinosi tol cycle, mobilization of intracellular calcium (Ca2*), and activation of protein kinase C (PKC) [10,13]. However, there are also marked differences in the dynamics and pathways of the transfer of the intracellular signal [5,10]. Meanwhile, the study of the mechanism of action of ET-1 is not only of theoretical, but also of practical interest, since it has been suggested that ET directly participates in such pathological processes as the development of ischemic damage to the brain [6], changes in the neurosecretory processes, a reduction of afferent

Binding and internalization of the synthetic double-stranded complex poly(A) · poly(U) were studied on a murine monocyte/macrophage cell line J774A 1 . Poly(A) · poly(U) increased in a dose-dependent fashion the oligo-2′,5′-adenylate synthetase demonstrating that those cells were responsive to this agonist. Binding of [ 32 P]poly(A) · [ 32 P]poly(U) to the cells reached an apparent kinetic equilibrium within 4 h and was saturable (apparent K d = 9.99 ± 0.09 · 10 −2 g/l and B max 13.3 ± 5.3 · 10 −3 g/l per 10 6 cells) and temperature-dependent. The binding of poly(A) · poly(U) was competitively inhibited by various polynucleotides but not by other structurally unrelated compounds. Analysis of cell-associated [ 32 P]poly(A) · [ 32 P]poly(U) demonstrated a minimal degration of this polyribonucleotide over a 4-h incubation period. Autoradiography of cells incubated with [ 3 H]poly(A) · [ 3 H]poly(U) revealed that poly(A) · poly(U) was internalized and migrated to cell nuclei. These results suggest that poly(A) · poly(U) is internalized in J774A 1 cells via an endocytotic process.

Background This study examined whether cicletanine, an antihypertensive drug with cGMP phosphodiesterase inhibitory effect, could alleviate ventricular overdrive pacing-induced myocardial ischemia in chronically instrumented rabbits. Methods An electrode-catheter implanted into the right ventricle was used for pacing (500 bpm over 5 min) and for measuring intracavital ST-segment elevation and ventricular effective refractory period (VERP). PQ and QT intervals were measured in the chest-lead ECG, and dP/dtmax as well as left ventricular end-diastolic pressure (LVEDP) were recorded through a left intraventricular catheter. In separate groups, mean arterial blood pressure (MABP) was monitored from the right carotid artery. Experiments were performed on conscious rabbits after a week of convalescence. In anesthetized, open-chest rabbits, samples were taken from the left ventricle before and after drug treatment and/or overdrive pacing for determination of cGMP and cAMP contents by radioimmunoassay. Results Intravenous cicletanine, 30 mg/kg body weight, did not change resting MABP, dP/dtmax, and LVEDP, but it did reduce heart rate and prolonged PQ and QT intervals and VERP. Overdrive pacing produced intracavital ST-segment elevation, increased LVEDP, and decreased dP/dtmax and MABP. Cicletanine administered 15 minutes before pacing significantly attenuated ST-segment elevation, increased LVEDP, and decreased dP/dtmax and MABP. In anesthetized animals, cicletanine itself slightly increased cardiac cGMP and cAMP contents. Overdrive pacing moderately increased cGMP and profoundly elevated cAMP, and in overpaced rabbits, cicletanine further increased cGMO and markedly attenuated cAMP content increased by overdrive pacing. Conclusions These results suggest that in correlation with alterations of cardiac cycle nudeotide contents, cicletanine protects the heart against pacing-induced myocardial ischemia.

Normal human peripheral blood mononuclear cells (PBMC) produced IgE when stimulated with IL-4. In the present report it was shown that beta 2-adrenoceptor agonists, salbutamol and fenoterol, potentiated the IL-4-induced IgE production without significantly affecting the expression of the low affinity receptor for IgE at the cell surface of monocytes and B lymphocytes. However, beta 2-adrenoceptor agonists were shown to enhance at day 7 the IL-4-induced release of the soluble form of CD23 (sCD23) by PBMC. This effect was specific since a beta-adrenoceptor antagonist, D,L-propranolol, inhibited the IL-4-induced IgE production by these cells. Alternatively, the beta 2-adrenoceptor agonists inhibited the production by these cells of interferon-gamma (IFN-gamma) but did not affect the production of IL-4 when stimulated with phytohemagglutinin A + a phorbol ester. These data suggest that beta 2-adrenoceptor agonists influence the IL-4-induced IgE production in humans by enhancing the release of sCD23 and inhibiting the production of endogenous IFN-gamma. In addition to the effect on the IL-4-induced IgE production it was shown that beta 2-adrenoceptor agonists potentiated the effect of IL-4 on a human promonocytic cell line, U 937, by enhancing CD23 expression and release and by inducing the differentiation of these cells into monocyte-like cells. Taken together, these data indicate that beta 2-adrenoceptor agonists potentiated the effect of IL-4 and that this functional interaction is different considering the cell-lineage and the stage of differentiation of these cells.

International audience; An 88-year-old woman was admitted for syncope andbradycardia. She complained of recent fatigue and weightloss. After insertion of a pacemaker device, the clinicalcourse was complicated by fever and a seizure. Eventually,we found that a multivisceral culture-positive tuberculousreactivation was likely to account for these symptoms.Radiological workup including 18-fluorodeoxyglucose-positron emission tomography (FDG-PET) yielded amyocardial tuberculoma (Figure1). Myocardial involve-ment is rare compared with the classical pericarditis indisseminated tuberculosis [1], but it may have specific pre-sentations like syncope, palpitations or cardiac failure. Todiagnose disseminated tuberculosis, FDG-PET can beuseful when culture or histopathology is difficult orimpossible [2]. It is a promising technique for therapeuticmonitoring, as it may guide early interventions [3]. Thepatient was treated medically with antituberculous therapyfor 12 months. She was alive 24 months later and the onlysequela was a complete atrioventricular block

Chloroquine retinopathy is a severe toxic retinal impairment which may result in loss of vision by alterations of the retinal pigment epithelium and photoreceptors. Currently, there is no specific treatment for this retinopathy. Platelet-activating factor (PAF) is known to modulate retinal function and is one of the major immunomediators of the retina. In order to test the possible involvement of PAF in chloroquine-induced retinopathy and the effectiveness of PAF antagonists in the prevention of this condition, we investigated the effects of BN 50730, a specific PAF antagonist, on the electroretinogram (ERG) of the isolated rat retina exposed to chloroquine. When retinas from normal rats were perfused with chloroquine (10(-6) M), a marked and rapid decrease in b-wave amplitude was observed. In contrast, chloroquine had no effect on the b-wave of the retina isolated from animals pretreated with the PAF antagonist BN 50730 (30 mg/kg/day, i.p., for 5 days). The results obtained indicate that (i) chloroquine is a toxic drug for retinal function, (ii) PAF plays a key role in the mediation of chloroquine retinopathy and (iii) PAF antagonists may constitute valuable agents for the treatment of this retinal impairment.

We investigated the contribution of scavenging of oxygen free radicals to retinal ion contents during ischemia and reperfusion with the use of super-oxide dismutase (SOD, Sigma), allopurinol (Sigma)

The effect of the neutral endopeptidase inhibitor, phosphoramidon, on the bronchoconstriction induced by aerosolized bombesin in the guinea pig was investigated. Administered by aerosol for 1 min, bombesin (0.01 or 0.1 mg/ml) induced a dose-dependent increase in pulmonary inflation pressure. Pretreatment of the guinea-pigs with phosphoramidon (0.1 mM), administered by aerosol for 15 min, 15 min prior to challenge, markedly potentiated the increase in pulmonary inflation pressure induced by bombesin (0.01 mg/ml) and substance P (0.1 mg/ml). This result suggests a local hydrolysis of bombesin by airway neutral endopeptidase reducing the activity of this peptide on smooth muscle.

In conscious rabbits equipped with right ventricular electrode and left ventricular polyethylene catheters, zaprinast and cicletanine, inhibitors of phosphodiesterase (PDE) V and PDEs I and V, respectively, as well as verapamil, a Ca2+ channel blocker, decreased intracavital ST-segment elevation induced by ventricular overdrive pacing (VOP). Zaprinast and cicletanine attenuated VOP-induced QT reduction and increase in left ventricular end-diastolic pressure (LVEDP), whereas verapamil increased LVEDP. These results suggest that inhibition of cGMP-PDEs can protect heart against ischemia.

Hypertension causes major structural vascular modifications including increase of wall:lumen ratio, vessel wall hypertrophy, and rarefaction of arterioles and small arteries. These structural alterations are accompanied with vascular dysfunctions. The stimuli responsible for this vascular remodeling are numerous and comprise physical, humoral, and locally synthetized factors. Among them, vasoactive substances such as vasoconstrictors (e.g., angiotensin II and endothelin) or vasodilating substances (e.g., prostacyclin and nitric oxide) may play a role as important as those of growth factors. The vascular protection afforded by antihypertensive drugs depends on their mode and their site of action and probably on their direct interference with the local hemodynamic and growth-affecting factors. This is well illustrated by cicletanine, a new antihypertensive agent that provides a good example of protection of the vasculature. This also emphasizes that vascular remodeling is important in hypertension and must be considered as an essential property of any new antihypertensive drug.

The interactions between L-arginine, the source of nitric oxide formation, and N G-nitro-L-arginine (L-NOARG), an inhibitor of nitric oxide synthase were examined in isolated rat aorta. Carbachol induced endothelium-dependent relaxation was used to study the constitutive form of the enzyme, whereas the loss of contraction tonicity to phenylephrine following incubation of endothelium free rings with interleukin 1 was used to investigate the smooth muscle inducible form. L-NOARG is a potent inhibitor of the two types of the enzyme in the rat aorta. However, the effects of L-NOARG on the constitutive (endothelial) vascular NO synthase were partially prevented, but not reversed, by L-arginine. In contrast, L-arginine fully reversed the action of L-NOARG on the smooth muscle inducible form of NO synthase. The selective reversibility of L-NOARG on the inducible, by comparison with the constitutive form of nitric oxide synthase present in the vasculature, may represent a limitation in the use of this type of com...

One of the major biological effects of the endothelium-derived peptide endothelin-1 (ET-1) is its receptor-mediated constrictive action on vascular smooth muscle. In this study, we have examined the effects on the ET-1 pathway of 18 h exposure at 37 degrees C of cultured rat aortic smooth muscle cells to dexamethasone (DEX) and phosphoramidon. ET-1 synthesis was evaluated by radioimmunoassay, ET-1 binding characteristics were determined with [125I]iodo-ET-1, and ET-1-induced intracellular calcium mobilization was measured using fura-2-loaded cells. DEX (100 nM) led to a 2- to 3-fold-increase of ET-1 production, it down-regulated ET-1 receptors and reduced ET-1-stimulated calcium mobilization by 70%. In contrast, phosphoramidon (100 microM) inhibited ET-1 production by 60%, up-regulated ET-1 receptors and potentiated ET-1-induced calcium mobilization by 75%. These results indicate that the regulatory effects of DEX and phosphoramidon on ET-1 receptors are mediated via ET-1 production by the cells. This suggests an autocrine control of ET-1 receptors by endogenous ET-1 synthesis in vascular smooth muscle cells.

[3H]Platelet-activating factor (PAF) binding to rabbit platelet membranes was examined before and after 20 min preincubation at 25 degrees C in the presence of PAF, lysoPAF, or of five different PAF receptor antagonists (L 652731, BN 52021, WEB 2086, BN 52111 and BN 52115). When platelet membranes were not washed after preincubation with PAF or PAF antagonists, no significant specific binding of [3H]PAF was observed, which suggests full occupancy of the binding sites. When membranes were extensively washed, full recovery of specific [3H]PAF binding was attained with L 652731 and partial recoveries (60%, 55% and 30%) were reached with BN 52021, WEB 2086 and PAF, respectively; no recovery was seen with the dioxolanes BN 52111 and BN 52115. Scatchard analysis of the binding data indicated that no significant change in the dissociation constant (Kd) and maximum number of binding sites (Bmax) occurred after preincubation of platelet membrane with L 652731, whereas a reduction of Bmax was observed when PAF and BN 52021 were measured. When platelet membranes were preincubated with WEB 2086, Bmax and Kd significantly increased. The data suggest differing binding properties for PAF and the PAF antagonists. Some of the PAF antagonists may tightly bind to the PAF receptor site(s) and/or irreversibly modify or downregulate PAF recognition sites. Our results also suggest that the interaction of PAF receptor antagonists with PAF receptor can be divided into at least two components, namely a reversible component and an irreversible one.

Using Sprague-Dawley rats with transient (90-min) regional ischaemia induced by retinal artery occlusion in the eye, we have shown that superoxide dismutase (SOD) and EGB 761 (IPSEN, France), two free radical scavengers, can dramatically reduce the reperfusion-induced sodium and calcium gains, and potassium loss in retinal tissue. Investigating whether this was a 'direct' protective effect, operating during reperfusion, or an 'indirect' effect arising from the action of SOD or EBG 761 on the tissue during ischaemia. SOD (15,000 U kg-1) and EGB 761 (100 mg kg-1) were added to the rats at the moment of reperfusion (after an ischaemic insult). Eyes were subjected to 90 min ischaemia followed by 4 and 24 hr of reperfusion, respectively. In the drug-free control group, 90 min of ischaemia resulted in an accumulation of retinal sodium (2-fold) and calcium (3-fold), and a loss of cell potassium (by 40%) and magnesium (by 40%). During the first 4 hr of reperfusion the ionic imbalance was unchanged, while after 24 hrs of reperfusion a normalization was observed and the ion content of the retina almost returned to their preischaemic values. SOD and EGB 761 treatment significantly reduced the reperfusion-induced ionic imbalance (magnesium was an exception) and improved the recovery of retinal ion contents. Our results indicate that the elimination of oxygen radicals by free radical scavengers may reduce the reperfusion-induced ionic imbalance and improve the ionic homeostasis in the injured retinal cells.

In anaesthetized and ventilated guinea-pigs, i.v. injection of 1 nmol/kg big endothelin-1 (big ET-1) did not evoke significant changes in pulmonary inflation pressure (PIP) and mean arterial blood pressure (MBP), whereas injection of the same dose of endothelin-1 (ET-1) induced marked and rapid bronchoconstrictor and pressor responses. Administered at the dose of 10 nmol/kg, big ET-1 provoked significant increases in PIP and MBP, which developed slowly and were long-lasting as compared to those evoked by ET-1. When big ET-1 was incubated for 45 min at 37°C with α-chymotrypsin (2 mU/nmol) or pepsin (1 μg/nmol) and then injected into guinea-pigs at the dose of 1 nmol/kg, marked bronchoconstrictor and pressor responses were observed, with kinetics similar to those noted after administration of the same dose of ET-1. The magnitude of the α-chymotrypsin- or pepsin-treated big ET-1 responses was similar to that induced by ET-1, incubated or not with the enzymes. Injected i.v. at the dose of 5 mg/kg, 5 min before the challenge, phosphoramidon almost totally inhibited the bronchoconstrictor and pressor responses induced by 10 nmol/kg big ET-1, whereas thiorphan (5 mg/kg) partially reduced the increase in PIP and exerted a minimal effect on the changes in MBP. Administered at the dose of 20 mg/kg per os, 1 h before i.v. administration of 10 nmol/kg big ET-1, enalapril maleate and captopril did not significantly alter the bronchoconstriction and the hypertensive response evoked by the peptide. The present results indicate that compared to ET-1, big ET-1 exhibits minimal direct bronchoconstrictor and pressor activities in the guinea-pig and has to be converted by proteolytic enzymes for full expression of its activity. The effects observed after administration of 10 nmol/kg big ET-1, as well as the inhibition of the bronchoconstrictor and pressor responses after treatment of the guinea-pigs with phosphoramidon, suggest that the peptide is metabolized in vivo into an active form and that neutral endopeptidase, or a metallopeptidase related to it, is involved in this process.

SUMMARYWe have studied the participation of platelet-activating factor (PAF) in antigen-induced arthritis in rabbits, as well as the possible co-operation between PAF and tumour necrosis factor (TNF) in their ability to induce joint inflammation when injected into the knees of healthy rabbits. The administration of two structurally different PAF receptor antagonists, BN52021 and Alprazolam, from 4 h before the intra-articular injection of ovalbumin in preimmunized rabbits, induced an important reduction in the synovial fluid volume, in the amount of cells infiltrating the articular cavity and the synovial membrane, as well as in the prostaglandin E2 (PGE2) concentration. Furthermore, proteoglycans of the articular cartilage, which were found diminished in animals with non-treated arthritis, were well preserved in rabbits treated with PAF antagonists. All the synovial fluids from joints with arthritis had detectable amounts of PAF. The injection of either TNFor PAF into the joints of normal rabbits induced a mild inflammation. When TNF was administered 1 h before PAF, a synergistic response was noted in the synovial fluid volume, in the accumulation of leucocytes, and in the amount of PGE2. The administration of BN50726, a hetrazepine with a potent PAF-receptor antagonist effect, induced a diminution in those parameters. Our results suggest that PAF may be an early and important mediator of joint damage, and that TNF can amplify the inflammatory response induced by PAF. PAF receptor antagonists could play some role in the treatment of inflammatory joint diseases.

Using decreasing concentrations of PAF-acether or thrombin, it was possible to observe on human platelets, first, aggregation, classically associated to activation, then , below a threshold, cytotoxicity towards Schistosoma mansoni larvae, proposed here as stimulation. These two activities appeared as distinct and antithetic. However, their induction might be the consequence of triggering of the same receptors with different intensity, since PAF-induced, but not thrombin-induced, cytotoxicity could be inhibited with specific PAF-antagonists BN 52021 and BN 52024 also known to inhibit PAF-induced aggregation. These results give credit to the hypothesis that haemostatic and cytotoxic properties of platelets are two distinct functions of these blood elements.

In experiments on anesthetized dogs, the effect of intracoronary administration of different doses of platelet-activating factor (PAF) has been investigated. One of the branches of the left coronary artery was catheterized via the main carotid artery. The coronary artery was autoperfused with blood from the subclavian artery. Intracoronary administration of small doses of PAF (100 and 200 ng/kg) caused a dose-dependent decrease in coronary resistance (CR) and an increase in coronary blood flow (CF). When 200 ng/kg of PAF was used, these changes were 30 and 34% vs. control, respectively. Dose increase to 300 ng/kg led to a biphasic reaction. Intracoronary administration of larger PAF doses produced opposite effects, i.e., increase in CR and decrease in CF. Chemical de-endothelialization by saponin (5 mg/5 ml, 1.5-2 min) transformed coronary dilation to small doses of PAF to constriction. The CR rose from 2.8 +/- 0.3 to 5.6 +/- 0.9 mm Hg/ml/min (p0.01) and CF dropped two-fold. The PAF receptor antagonists BN 52021 (6 mg/kg) and WEB 2086 (3 mg/kg) completely abolished PAF-induced coronary reactions. Hence, PAF-induced vasodilation of the canine coronary circulation is endothelium dependent.

We studied the effects of cicletanine, a furopyridine antihypertensive drug, and furosemide, a loop diuretic, on ventricular arrhythmias, such as sustained ventricular fibrillation (VF) and ventricular tachycardia (VT), and myocardial ion content in Langendorff rat hearts subjected to 30min global ischaemia then 10 min reperfusion. Myocardial Na+ K+ Ca2+ and Mg2+ concentrations were measured by washout technique and atomic absorption spectrophotometry before and after ischaemia and reperfusion. Drugs were either perfused (acute treatment) or orally gavaged daily to the rats for 14 days before isolation of their hearts (chronic treatment). Under in vitro conditions 10−5, 3 × 10−5, 10−4 or 3 × 10−4 M of cicletanine reduced the incidence of sustained VF and VT from the control values of 91% and 100% to 83% and 100%, 50% (P

To assess the effects of endothelin 1 (ET) on the pulmonary and systemic vascular beds simultaneously, we examined the hemodynamic responses to ET in awake calves implanted with a Jarvik total artificial heart (TAH), a device that maintains constant cardiac output (CO). During basal conditions, successive incremental intravenous (i.v.) injections of 1, 3, and 10 micrograms ET caused a dose-dependent decrease in pulmonary arterial pressure (PAP), (from 24 +/- 3 to 15 +/- 1 mm Hg, p less than 0.05) while having no effect on systemic arterial (SAP), left atrial (LAP), and right atrial (RAP) pressures. Administration of 30 micrograms ET i.v. also decreased PAP, had no effect on LAP and RAP, but increased SAP from 100 +/- 6 to 118 +/- 4 mm Hg (p less than 0.05). The decrease in PAP was rapid, occurring within seconds and lasting 10 min, whereas the increase in SAP occurred after 2-5 min and was prolonged for greater than or equal to 20 min. As compared with injection in the right atrium, administration of 30 micrograms ET into the left atrium reduced PAP to a similar extent, but induced a greater increase in SAP (+32.5 +/- 4 vs +17.5 +/- 2 mm Hg, p less than 0.05). ET also dose-dependently reversed the acute pulmonary vasoconstriction induced by inhalation of an hypoxic gas mixture. In all cases, pulmonary vasodilation occurred without evidence of short-term tolerance. The results demonstrate that ET is a potent in vivo pulmonary vasodilator. In calves, the predominant hemodynamic response to ET is pulmonary vasodilation, with systemic vasoconstriction apparent only at higher concentrations of the peptide.

Using human platelet-rich plasma (PRP) we found that histamine concentration-dependently potentiated platelet aggregation induced by platelet-activating factor (PAF). When added separately, neither histamine nor chloropyramine, a competitive antagonist of H1 receptors, influenced platelet aggregation, however BN 52021, a specific PAF receptor antagonist, concentration-dependently inhibited the response. Chloropyramine reduced the potentiating effect of histamine on PAF-induced platelet aggregation, and when it was coadministered with BN 52021, inducing 63% inhibition of PAF-induced aggregation, the histamine-potentiated PAF response was completely abolished. This observation draws attention to the importance of cooperation between histamine and PAF in mediation of platelet aggregation in human PRP, and points to the powerful antiaggregatory effect of BN 52021 combined with an antagonist of H1 receptors.