Studies of antibacterial activity (in vitro and in vivo) and mode of action for des-acyl tridecaptins (DATs)

Tridecaptins comprise a class of linear cationic lipopeptides with an N-terminal fatty acyl moiety. These 13-mer antimicrobial peptides consist of a combination of d- and l-amino acids, conferring increased proteolytic stability. Intriguingly, they are biosynthesized by non-ribosomal peptide synthetases in the same bacterial species that also produce the cyclic polymyxins displaying similar fatty acid tails. Previously, the des-acyl analog of TriA1 (termed H-TriA1) was found to possess very weak antibacterial activity, albeit it potentiated the effect of several antibiotics. In the present study, two series of des-acyl tridecaptins were explored with the aim of improving the direct antibacterial effect. At the same time, overall physico-chemical properties were modulated by amino acid substitution(s) to diminish the risk of undesired levels of hemolysis and to avoid an impairment of mammalian cell viability, since these properties are typically associated with highly hydrophobic cationic peptides. Microbiology and biophysics tools were used to determine bacterial uptake, while circular dichroism and isothermal calorimetry were used to probe the mode of action. Several analogs had improved antibacterial activity (as compared to that of H-TriA1) against Enterobacteriaceae. Optimization enabled identification of the lead compound 29 that showed a good ADMET profile as well as in vivo efficacy in a variety of mouse models of infection.

Optimization of the Antibacterial Spectrum and the Developability Profile of the Novel-Class Natural Product Corramycin

Corramycin 1 is a novel zwitterionic antibacterial peptide isolated from a culture of the myxobacterium Corallococcus coralloides. Though Corramycin displayed a narrow spectrum and modest MICs against sensitive bacteria, its ADMET and physchem profile as well as its high tolerability in mice along with an outstanding in vivo efficacy in an Escherichia coli septicemia mouse model were promising and prompted us to embark on an optimization program aiming at enlarging the spectrum and at increasing the antibacterial activities by modulating membrane permeability. Scanning the peptidic moiety by the Ala-scan strategy followed by key stabilization and introduction of groups such as a primary amine or siderophore allowed us to enlarge the spectrum and increase the overall developability profile. The optimized Corramycin 28 showed an improved mouse IV PK and a broader spectrum with high potency against key Gram-negative bacteria that translated into excellent efficacy in several in vivo mouse infection models.

Structure Elucidation, Total Synthesis, Antibacterial In Vivo Efficacy and Biosynthesis Proposal of Myxobacterial Corramycin

Herein, we describe the myxobacterial natural product Corramycin isolated from Corallococcus coralloides. The linear peptide structure contains an unprecedented (2R,3S)-γ-N-methyl-β-hydroxy-histidine moiety. Corramycin exhibits anti-Gram-negative activity against Escherichia coli (E. coli) and is taken up via two transporter systems, SbmA and YejABEF. Furthermore, the Corramycin biosynthetic gene cluster (BGC) was identified and a biosynthesis model was proposed involving a 12-modular non-ribosomal peptide synthetase/polyketide synthase. Bioinformatic analysis of the BGC combined with the development of a total synthesis route allowed for the elucidation of the molecule's absolute configuration. Importantly, intravenous administration of 20 mg kg-1 of Corramycin in an E. coli mouse infection model resulted in 100 % survival of animals without toxic side effects. Corramycin is thus a promising starting point to develop a potent antibacterial drug against hospital-acquired infections.

[Are abdominal aortic aneurysm screening guidelines followed? Prospective study in Dunkerque's hospital emergency room]

AIM OF THE STUDY

Are the recommendations issued by the Haute Autorité de santé in 2012 on screening for abdominal aortic aneurysm (AAA) being applied?

METHOD

We interviewed the target patients, ex. male patients aged 65 to 75, smokers or former smokers, or as young as 50 in the event of a family history of AAA in the parents or siblings, entering the emergency room of Dunkerque between May 7 and December 31, 2015. We asked them if they had had an abdominal aortic ultrasound, or an abdominal ultrasound, or an arterial Doppler ultrasound of the lower limbs, and when, to see if they had had an AAA test since November 2012.

RESULTS

We included 55 patients and excluded 5 of 180 eligible patients (31 %). It was not possible to conclude for 4 patients due to missing data. Thirteen of 46 patients (28.3 %, 95 % CI [16.0-43.5]) have had AAA ultrasound screening since November 2012; 33 have not (71.7 %, 95 % CI [56.5-84.0]) and no screening was offered. Of the 13 patients screened, 7 were screened by the attending physician (53.9 %, 95 % CI [25.1-80.8]) and 6 by another specialist (46.2 %, 95 % CI [19.2-74.9]).

CONCLUSION

AAA screening in our population is low. Physicians should be urged to publicize and implement the November 2012 French recommendations to reduce AAA-related mortality.

Total Synthesis and Structural Revision of the Antibiotic Tetrapeptide GE81112A

The total synthesis of the naturally occurring antibiotic GE81112A, a densely functionalized tetrapeptide, is reported. Comparison of spectral data with those of the natural product and the lack of biological activity of the synthesized compound led us to revise the published configuration of the 3-hydroxypipecolic acid moiety. This hypothesis was fully validated by the synthesis of the corresponding epimer.

[Neonatal hyperthyroidism: A sometimes challenging diagnosis]

Graves disease complicates two pregnancies out of 1000 and when it is known before pregnancy, it warrants careful monitoring of the fetus and the newborn. We report on a case of neonatal hyperthyroidism, which revealed a previously unknown maternal thyroid disease. In this situation, neonatal signs can be misinterpreted, delaying the diagnosis. Neonatal hyperthyroidism is, however, a therapeutic emergency because of the risk of cardiac and neurological complications. The neonatologist must identify thyroid disease in the absence of a maternal history in order to promptly start therapy.

H.E.S.S. Limits on Linelike Dark Matter Signatures in the 100 GeV to 2 TeV Energy Range Close to the Galactic Center

A search for dark matter linelike signals iss performed in the vicinity of the Galactic Center by the H.E.S.S. experiment on observational data taken in 2014. An unbinned likelihood analysis iss developed to improve the sensitivity to linelike signals. The upgraded analysis along with newer data extend the energy coverage of the previous measurement down to 100 GeV. The 18 h of data collected with the H.E.S.S. array allow one to rule out at 95% C.L. the presence of a 130 GeV line (at l=-1.5°, b=0° and for a dark matter profile centered at this location) previously reported in Fermi-LAT data. This new analysis overlaps significantly in energy with previous Fermi-LAT and H.E.S.S.

RESULTS

No significant excess associated with dark matter annihilations was found in the energy range of 100 GeV to 2 TeV and upper limits on the gamma-ray flux and the velocity weighted annihilation cross section are derived adopting an Einasto dark matter halo profile. Expected limits for present and future large statistics H.E.S.S. observations are also given.

Search for Dark Matter Annihilations towards the Inner Galactic Halo from 10 Years of Observations with H.E.S.S

The inner region of the Milky Way halo harbors a large amount of dark matter (DM). Given its proximity, it is one of the most promising targets to look for DM. We report on a search for the annihilations of DM particles using γ-ray observations towards the inner 300 pc of the Milky Way, with the H.E.S.S. array of ground-based Cherenkov telescopes. The analysis is based on a 2D maximum likelihood method using Galactic Center (GC) data accumulated by H.E.S.S. over the last 10 years (2004-2014), and does not show any significant γ-ray signal above background. Assuming Einasto and Navarro-Frenk-White DM density profiles at the GC, we derive upper limits on the annihilation cross section ⟨σv⟩. These constraints are the strongest obtained so far in the TeV DM mass range and improve upon previous limits by a factor 5. For the Einasto profile, the constraints reach ⟨σv⟩ values of 6×10^{-26}  cm^{3} s^{-1} in the W^{+}W^{-} channel for a DM particle mass of 1.5 TeV, and 2×10^{-26}  cm^{3} s^{-1} in the τ^{+}τ^{-} channel for a 1 TeV mass. For the first time, ground-based γ-ray observations have reached sufficient sensitivity to probe ⟨σv⟩ values expected from the thermal relic density for TeV DM particles.

Constraints on an annihilation signal from a core of constant dark matter density around the milky way center with H.E.S.S

An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of ∼9  h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of ∼300  GeV to ∼10  TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24}  cm^{3}/s are excluded for dark matter particles with masses between ∼1 and ∼4  TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.

Nanomolar inhibitors of Mycobacterium tuberculosis glutamine synthetase 1: synthesis, biological evaluation and X-ray crystallographic studies

A series of imidazo[1,2-a]indeno[1,2-e]pyrazin-4-ones that potently inhibit M. tuberculosis glutamine synthetase (GlnA1) has been identified by high throughput screening. Exploration of this series was performed owing to a short chemistry program. Despite possibly nanomolar inhibitions, none of these compounds was active on whole cell Mtb, suggesting that GlnA1 may not be a suitable target to find new anti-tubercular drugs.

Capped guanidino-α-cyclodextrin first synthesis based on intramolecular Staudinger-Aza-Wittig (SAW) reaction

An intramolecularly promoted SAW reaction between a phosphinimide and an isocyanate intermediate led to an original bridged trisubstituted ((A,C),E)-α-cyclodextrin. The latter was in a second step converted into a new capped (ACE)-(guanidino)-α-cyclodextrin.

Search for photon-linelike signatures from dark matter annihilations with H.E.S.S

Gamma-ray line signatures can be expected in the very-high-energy (E(γ)>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Using data collected with the H.E.S.S. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼ 500 GeV and ∼ 25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. No statistically significant signal could be found. For monochromatic γ-ray line emission, flux limits of (2 × 10(-7) -2 × 10(-5)) m(-2) s(-1) sr(-1) and (1 × 10(-8) -2 × 10(-6)) m(-2) s(-1)sr(-1) are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩(χχ → γγ) reach ∼ 10(-27) cm(3)s(-1), based on the Einasto parametrization of the Galactic DM halo density profile.

Protective effect of single-dose adjuvanted pandemic influenza vaccine in children

Please cite this paper as: Van Buynder et al. (2010) Protective effect of single‐dose adjuvanted pandemic influenza vaccine in children. Influenza and Other Respiratory Viruses 4(4), 171–178.

Background  During the first wave of A/California/7/2009(H1N1) influenza, high rates of hospitalization in children under 5 years were seen in many countries. Subsequent policies for vaccinating children varied in both type of vaccine and number of doses. In Canada, children 36 months to <10 years received a single dose of 0·25 ml of the GSK adjuvanted vaccine (Arepanrix™) equivalent to 1·9 μg HA. Children 6 months to 35 months received two doses as did those 36–119 months with chronic medical conditions.

Method  We conducted a community‐based case–control vaccine effectiveness (VE) review of children under 10 years with influenza like illness who were tested for H1N1 infection at the central provincial laboratory. Laboratory‐confirmed influenza was the primary outcome, and vaccination status the primary exposure to assess VE after a single 0·25‐ml dose.

Results  If vaccination was designated to be effective after 14 days, no vaccinated child had laboratory‐confirmed influenza compared to 38% of controls. The VE of 100% was statistically significant for children <10 years of age and <5 years considered separately. If vaccination was considered effective after 10 days, VE dropped to 96% overall but was statistically significant and over 90% in all age subgroups, including those under 36 months.

Conclusions  A single 0·25‐ml dose of the GSK adjuvanted vaccine (Arepanrix™) protects children against laboratory‐confirmed pandemic influenza potentially avoiding any increased reactogenicity associated with second doses. Adjuvanted vaccines offer hope for improved seasonal vaccines in the future.

Aziridinium from N,N-Dibenzyl Serine Methyl Ester: Synthesis of Enantiomerically Pure β-Amino and α,β-Diamino Esters

[reaction: see text] Reaction of N,N-dibenzyl-O-methylsulfonyl serine methyl ester with a variety of heteronucleophiles (sodium azide, sodium phthalimide, amines, thiols) and carbanions (sodium malonate) gave, via an aziridinium intermediate, the corresponding beta-amino or alpha,beta-diamino ester in good to excellent yield. A short synthesis of orthogonally protected and enantiomerically pure 2,3-diamino propionate (Dap) is described.

Unexpected isolation, and structural characterization, of a beta-hydrogen-containing sigma-alkylpalladium halide complex in the course of an intramolecular heck reaction. synthesis of polycyclic isoquinoline derivatives

The isolation of a stable beta-hydrogen-containing R-PdLn-X complex (R = alkyl; X = halide) issued from a Heck reaction is reported together with some aspects of its reactivity.

[Dorsal instability of the ulnar stump following distal resection: hemi extensor-carpi-ulnaris stabilization procedure]

Dorsal instability of the ulnar stump may be a complication of Darrach and Sauve-Kapandji procedures. Stabilizing procedures are numerous using flexor carpi ulnaris, extensor carpi ulnaris tendons or a combination of both tendons, the palmaris longus, and even synthetic or free grafts. The authors report nine cases of ulnar stump instability, five times post-traumatic and four as a result of rheumatoid arthritis. A tenodesis using a strip half of the extensor carpi ulnaris was performed in all these patients. Post-operatively eight patients were pain-free with in one case occasional pain after heavy work. All stumps were clinically stable. Forearm rotation and grip strength were maintained. Radiological dorsal ulnar subluxation was always reduced. Treatment of these instabilities should be preventive. When dorsal instability of the ulnar stump occurs, the half strip extensor carpi ulnaris tenodesis provides consistent satisfactory results in both arthritic and post-traumatic-related instability.

[Lunocapitate shortening arthrodesis after scaphoid and triquetrum resection: treatment of Watson stage III advanced scaphoid periarthrosis]

PURPOSE OF THE STUDY

Between 1993 and 2000, 16 patients with scaphoid periarthrosis (Watson stage III) were treated by lunocapitate shortening arthrodesis after resection of the scaphoid and triquetrum. These patients were reviewed to evaluate outcome.

MATERIAL AND METHODS

Thirteen patients had antecedent trauma with scaphoid nonunion (SNAC, n=9) or scapholunate advanced collapse (SLAC, n=4). The remaining three patients had chondrocalcinosis.

RESULTS

Clinical and radiological results were encouraging at a mean follow-up of 3 years (1-7 years). Fourteen patients were very satisfied and two experienced partial improvement. Persistent pain relief as well as 11% improved muscle power was achieved. Mean improvement of joint motion was 12 degrees.

DISCUSSION

This technique has shown better global results than 4-corner arthrodesis. It can be applied if capitate arthrodesis is performed. Results are comparable to those of proximal row carpectomy.

Java-based graphical user interface for MRUI, a software package for quantitation of in vivo/medical magnetic resonance spectroscopy signals

This article describes a Java-based graphical user interface for the magnetic resonance user interface (MRUI) quantitation package. This package allows MR spectroscopists to easily perform time-domain analysis of in vivo/medical MR spectroscopy data. We have found that the Java programming language is very well suited for developing highly interactive graphical software applications such as the MRUI system. We also have established that MR quantitation algorithms, programmed in the past in other languages, can easily be embedded into the Java-based MRUI by using the Java native interface (JNI).

Java-based graphical user interface for the MRUI quantitation package

This article describes the Java-based version of the magnetic resonance user interface (MRUI) quantitation package. This package allows MR spectroscopists to easily perform time-domain analysis of in vivo MR spectroscopy data. We show that the Java programming language is very well suited for developing highly interactive graphical software applications such as the MRUI software. We have also established that MR quantitation algorithms, programmed in other languages, can easily be embedded into the Java-based MRUI by using the Java native interface (JNI). This new graphical user interface (GUI) has been conceived for the processing of large data sets and uses prior knowledge data-bases to make interactive quantitation algorithms more userfriendly.

Protein kinase A-dependent stimulation of rat type II secreted phospholipase A(2) gene transcription involves C/EBP-beta and -delta in vascular smooth muscle cells

Type II secreted phospholipase A(2) (sPLA(2)) releases precursors of important inflammatory lipid mediators from phospholipids. Some observations have indicated that the sPLA(2), which has been implicated in chronic inflammatory conditions such as arthritis, contributes to atherosclerosis in the arterial wall. sPLA(2) was not detected in control vascular smooth muscle cells (VSMC). Treatment of VSMC with agents that increase intracellular cAMP (eg, forskolin, dibutyryl [db]-cAMP) resulted in a time- and concentration-dependent increase in sPLA(2) gene expression. Semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) showed a marked dose-dependent inhibition of forskolin-induced mRNA by protein kinase A inhibitor. Electrophoretic mobility shift analysis of nuclear proteins from forskolin-treated and db-cAMP-treated VSMC with C/EBP consensus oligonucleotides and C/EBP oligonucleotides from the rat promoter revealed greater binding than in control VSMC. Incubation of VSMC with H89, a specific protein kinase inhibitor, also blocked the binding of nuclear C/EBP to the C/EBP site of the rat promoter induced by db-cAMP and forskolin. Binding was unchanged with the use of CRE consensus oligonucleotides. Antibodies revealed the specific formation of C/EBP/DNA complexes, the majority of which were supershifted by C/EBP-ss and -delta antibodies. Functional activation of C/EBP was confirmed by a luciferase reporter gene assay. A construct comprising 4 tandem repeat copies of the C/EBP element from the rat sPLA(2) promoter linked to luciferase was transcriptionally activated in VSMC by cotransfection with expression vector for the protein kinase A catalytic subunit. It was also significantly activated in transfected VSMC treated by forskolin or db-cAMP. H89 inhibited this activations. We therefore conclude that the increases in sPLA(2) mRNA and enzyme activity produced by cAMP-elevating agents is controlled by a mechanism involving nuclear C/EBP-ss and -delta acting through a protein kinase A signaling pathway.

Interleukin 1beta induces type II-secreted phospholipase A(2) gene in vascular smooth muscle cells by a nuclear factor kappaB and peroxisome proliferator-activated receptor-mediated process

Type II-secreted phospholipase A(2) (type II-sPLA(2)) is expressed in smooth muscle cells during atherosclerosis or in response to interleukin-1beta. The present study shows that the induction of type II-sPLA(2) gene by interleukin-1beta requires activation of the NFkappaB pathway and cytosolic PLA(2)/PPARgamma pathway, which are both necessary to achieve the transcriptional process. Interleukin-1beta induced type II-sPLA(2) gene dose- and time-dependently and increased the binding of NFkappaB to a specific site of type II-sPLA(2) promoter. This effect was abolished by proteinase inhibitors that block the proteasome machinery and NFkappaB nuclear translocation. Type II-sPLA(2) induction was also obtained by free arachidonic acid and was blocked by either AACOCF(3), a specific cytosolic-PLA(2) inhibitor, PD98059, a mitogen-activated protein kinase kinase inhibitor which prevents cytosolic PLA(2) activation, or nordihydroguaiaretic acid, a lipoxygenase inhibitor, but not by the cyclooxygenase inhibitor indomethacin, suggesting a role for a lipoxygenase product. Type II-sPLA(2) induction was obtained after treatment of the cells by 15-deoxy-Delta(12,14)-dehydroprostaglandin J(2), carbaprostacyclin, and 9-hydroxyoctadecadienoic acid, which are ligands of peroxisome proliferator-activated receptor (PPAR) gamma, whereas PPARalpha ligands were ineffective. Interleukin-1beta as well as PPARgamma-ligands stimulated the activity of a reporter gene containing PPARgamma-binding sites in its promoter. Binding of both NFkappaB and PPARgamma to their promoter is required to stimulate the transcriptional process since inhibitors of each class block interleukin-1beta-induced type II-sPLA(2) gene activation. We therefore suggest that NFkappaB and PPARgamma cooperate at the enhanceosome-coactivator level to turn on transcription of the proinflammatory type II-sPLA(2) gene.

Effects of caffeine on lipoprotein lipase gene expression during the adipocyte differentiation process

In this study, the effects of caffeine on lipoprotein lipase (LPL) gene expression were investigated in the 3T3-F442A preadipocyte cell line during the adipocyte differentiation process by determining LPL enzymatic activity and its messenger RNA (mRNA) level. The results demonstrate that caffeine acts on the gene expression of LPL, an early marker of adipocyte differentiation. It has a biphasic action: it increases gene expression in terms of mRNA when it is added to preadipocytes during the early stage of differentiation, but this is accompanied by a reduction of enzymatic activity. On the other hand, when caffeine is added for long periods during differentiation and/or when it is added to mature adipocytes, it induces marked inhibition of mRNA levels, correlated with a marked reduction of secreted enzymatic activity. The inhibitory effect of caffeine on LPL mRNA level can be reproduced by theophylline, a phosphodiesterase inhibitor, and by dibutyryl cyclic AMP, a non-metabolizable analog of cyclic AMP. However, the effect of caffeine and theophylline lasts longer than that of cyclic AMP, suggesting that a mechanism other than inhibition of cyclic AMP hydrolysis may be involved in the action of caffeine.

[Resection of the fourth ray for annular lesions: amputations of the fourth ray of the hand]

INTRODUCTION

Several procedures have been reported for amputation of the fourth ray of the hand. Most surgeons recommend translocation of the fifth finger on the proximal end of the fourth metacarpal bone. Others prefer to perform a resection of the fourth metacarpal bone combined with intracarpal osteotomy.

MATERIAL AND METHODS

The authors' choice was to perform a resection of the fourth metacarpal bone with conservation of its proximal end. They emphased on two technical details: resection of the interosseous muscles and reconstruction of the intermetacarpal ligament. The present series includes 8 patients operated on with this technique. Results were assessed with an average follow-up of 47 months. Evaluation of the result was based on a personal rating score including 9 clinical scores and on 1 radiological measurement of the hand width.

RESULTS

Mobility of the adjacent digits was normal in all cases except one with a retractile scar. In 7 cases out of 8, the aesthetic result was satisfactory. Grip strength was 65 per cent of the contralateral side. Diminution of the hand width was of 12 per cent. Five results were excellent and three were good.

DISCUSSION

Translocation with intracarpal osteotomy can produce impairement of carpus function, especially with apparition of pain, but also some rotational malposition. Translocation of the fifth digit on the fourth metacarpal bone can also procedure an imbalance of the extrinsic muscles, but also a rotational malposition.

CONCLUSION

Transmetacarpal amputation of the fourth ray has the advantage to be an easy anatomic procedure, and is particularly reliable and reproductible regarding to the results. This procedure does not produce any specific complication comparing with other techniques.

New anionic polyelectrolyte hydrogel for corneal surgery

A new high-water-content (78%) anionic polyelectrolyte hydrogel was obtained by phase inversion (demixion) of a polymer solution containing 9.0% poly(acrylonitrile sodium methallylsulphonate), 85.0% dimethylformamide, and 6.0% saline solution (0.9% NaCl). The hydrogel is permeable to water, saline, urea, creatinine, glucose, human albumin, and saline-dissolved oxygen. Investigation of the interactions between human serum and surfaces prepared with the new yielded hydrogel, compared to serum interaction with silica-free silicone (RTV), regenerated cellulose (Cuprophan), MMA/PVP copolymer (Lidofilcon), PMMA (Perspex), FIFE (Gore-Tex), and poly(acrylonitrile sodium methallylsulphonate) hemodialysis membrane (AN-69), showed the hydrogel and hemodialysis membrane (both prepared with AN-69 copolymer) to be the only materials devoid of complement (C')-activating ability.

Effects of non-steroidal antiallergic eyedrops on the complement-mediated histamine release from human cells

Leukocytes from ten allergic patients (five allergic to dust-mites and five allergic to pollen) were treated with N-acetyl aspartyl glutamic acid (NAAGA) 4.9%, disodium cromoglycate (DSCG) 2%, lodoxamide (LODO) 1%, and levocabastine (LEVO) 0.5% (concentrations representing the pharmaceutical eyedrop preparations) for 20 minutes. Degranulation was then induced with Complement (rHu5Ca). Histamine was measured in the supernatant with ELISA. LODO and LEVO were inactive in blocking histamine released from human cells, and paradoxical unexpected effects were found with these two agents. They both induced significant histamine release in almost 100% of the samples. DSCG was able to block histamine release in seven patients out of nine (ranging between 5 and 34%). NAAGA was the most active agent on human cells and was able to block basophil degranulation in nine patients out of nine (inhibition ranging between 4 and 66% of total histamine pool).

Membrane molecules which trigger the production of interleukin-1 and tumor necrosis factor-alpha by lipopolysaccharide-stimulated human monocytes

We have investigated the role of the membrane molecules CD11/CD18 and CD14 which may mediate the binding of lipopolysaccharide (LPS) to human monocytes, in the induction of the production and release of interleukin (IL)-1 and tumor necrosis factor-alpha (TNF-alpha) by LPS-stimulated cells. Blockade of CD11a, CD11b and CD18 with saturating concentrations of specific mAb did not inhibit the release of cytokines from LPS-stimulated monocytes. In contrast, inhibition of the release of IL-1 beta and TNF-alpha occurred in monocytes cultures that had been pretreated with either of two monoclonal antibodies (mAb) recognizing different epitopes on the CD14 molecule. The binding of LPS to CD14 has been previously shown to require serum factors. In the present study, we found that serum had an enhancing effect on the release of IL-1 and TNF-alpha from LPS-stimulated cultures of normal human monocytes. The inhibitory effect of anti-CD14 mAb was, however, observed in cultures performed in the presence or in the absence of serum, suggesting that triggering of IL-1/TNF-alpha release by CD14 is independent of LPS-binding proteins or other serum proteins. IL-1 beta and TNF-alpha were also released from LPS-stimulated cultures of monocytes from patients with paroxysmal nocturnal hemoglobinuria lacking expression of CD14. Thus, CD14 but not CD11/CD18 can trigger serum-dependent and independent cytokine release from endotoxin-stimulated normal human monocytes; CD14 is not, however, the only LPS receptor that is involved in the secretory response of endotoxin-stimulated cells.

Binding sites for endotoxins (lipopolysaccharides) on human monocytes

The nature of the binding sites for LPS on human monocytes was investigated using [3H] labeled intact LPS from Neisseria meningitidis and from Salmonella minnesota R7, and the [3H] labeled purified inner core region (PS-OMe) of S.m. R7 LPS. In the presence of serum, intact LPS from enterobacterial and nonenterobacterial strains bound to monocytes in a dose-dependent, saturable, and displaceable fashion. N.m. LPS and LPS from the enterobacterial strain of Escherichia coli 0111-B4 bound to the same sites on monocytes as assessed in competitive binding experiments. Specific binding of intact LPS to monocytes occurred through the CD14 molecule as shown by the ability of mAb and of F(ab')2 fragments of mAb directed against specific epitopes of CD14 to inhibit the binding of [3H]-LPS to cells and by the lack of binding of intact LPS to CD14-deficient cells from patients with paroxysmal nocturnal hemoglobinuria. Specific binding of LPS to monocytes was not mediated by the CD11/CD18 complex because mAb to the alpha and beta chains of the Leu-CAM molecules did not alter the binding of LPS to cells and because LPS did not inhibit the binding of labeled mAb to monocytes. [3H]-PS-OMe also bound in a dose-dependent and displaceable fashion to monocytes involving an unidentified, non-CD14, binding site on the cells. Binding of LPS to monocytes also involved nonsaturable binding sites for hydrophobic structures of LPS as evidenced in binding experiments performed in the absence of serum. These observations indicate that intact LPS may interact with the monocyte membrane in at least three ways including serum-dependent binding to CD14 and to a lectin-like receptor, and serum-independent hydrophobic interactions.

Binding sites for endotoxins (lipopolysaccharides) on human monocytes

The nature of the binding sites for LPS on human monocytes was investigated using [3H] labeled intact LPS from Neisseria meningitidis and from Salmonella minnesota R7, and the [3H] labeled purified inner core region (PS-OMe) of S.m. R7 LPS. In the presence of serum, intact LPS from enterobacterial and nonenterobacterial strains bound to monocytes in a dose-dependent, saturable, and displaceable fashion. N.m. LPS and LPS from the enterobacterial strain of Escherichia coli 0111-B4 bound to the same sites on monocytes as assessed in competitive binding experiments. Specific binding of intact LPS to monocytes occurred through the CD14 molecule as shown by the ability of mAb and of F(ab')2 fragments of mAb directed against specific epitopes of CD14 to inhibit the binding of [3H]-LPS to cells and by the lack of binding of intact LPS to CD14-deficient cells from patients with paroxysmal nocturnal hemoglobinuria. Specific binding of LPS to monocytes was not mediated by the CD11/CD18 complex because mAb to the alpha and beta chains of the Leu-CAM molecules did not alter the binding of LPS to cells and because LPS did not inhibit the binding of labeled mAb to monocytes. [3H]-PS-OMe also bound in a dose-dependent and displaceable fashion to monocytes involving an unidentified, non-CD14, binding site on the cells. Binding of LPS to monocytes also involved nonsaturable binding sites for hydrophobic structures of LPS as evidenced in binding experiments performed in the absence of serum. These observations indicate that intact LPS may interact with the monocyte membrane in at least three ways including serum-dependent binding to CD14 and to a lectin-like receptor, and serum-independent hydrophobic interactions.

Central venous catheter-related complications in newborns and infants: a 587-case survey

In an attempt to identify factors determining central venous catheter-related complications in newborns and infants, 587 cases have been retrospectively analyzed. Attention has been paid to the influence of the incidence of babies' body weight, site of insertion, and technique of placement of the catheter and the material used, ie, silicone (SI) or polyurethane (PU). Overall complications occurred in 28% of the catheters with 2 deaths due to cardiac tamponade. Mechanical complications happened in 22% of the catheters, including dislodgement (11.6%), extracorporeal perforation (5.3%), and obstruction (5%). Septic complications occurred in 4% catheters, including proven bacteriemia (2.5%), abscess at the entry site (1%), and isolated fever (0.8%). Clinically evident caval thrombosis occurred in 1% of the catheters. Overall complications were significantly higher when the body weight was lower than 2,500 g (P less than .01) due to a significantly higher incidence of septic complications (P less than .05). When a proximal site of placement of the catheter was used, both septic and mechanical complications were more frequent than in the distal approach (P less than .01). The incidence of complications was similar in surgically and in percutaneously placed catheters as in SI and PU catheters. Nevertheless, fatal complications occurred only in PU catheters, leading us to avoid the choice of such material in newborns and small infants.

Induction of cell-associated interleukin 1 through stimulation of the adhesion-promoting proteins LFA-1 (CD11a/CD18) and CR3 (CD11b/CD18) of human monocytes

Serum-free culture of human monocytes in the presence of monoclonal antibodies to the LFA-1 alpha chain (CD11a), CR3 alpha chain (CD11b) or beta chain (CD18) bound to Sepharose induced the dose-dependent production of cell-associated interleukin (IL) 1 activity and of IL 1 alpha and IL 1 beta antigens, but no release of extracellular IL 1 activity or antigen in the culture medium. Triggering of IL 1 production was also observed with insolubilized anti-CD11/CD18 F(ab')2 antibodies. Two cross-linked antibodies recognizing distinct epitopes on the CD11b molecule induced cell-associated IL 1. Soluble antibodies did not induce IL 1 production. The kinetics of induction of IL 1 by stimulation of adhesion-promoting proteins differed from those of IL 1 induction by adhesion to plastic. The lack of induction of IL 1 release by stimulation of the CD11/CD18 molecules resembled the intracellular accumulation of IL 1 induced by lipid A. Induction of IL 1 by adhesive processes may be a mechanism by which T cells trigger IL 1 production by monocytes during antigen presentation.

Induction of IL-1 release through stimulation of the C3b/C4b complement receptor type one (CR1, CD35) on human monocytes

Soluble polymerized human C3b and C3b bound to Sepharose induced the production of cell-associated IL-1 and the extracellular release of IL-1 activity from cultured human adherent monocytes. Cultures were performed in serum-free conditions in the presence of polymyxin B and of the PG synthesis inhibitor indomethacin. Induction of intracellular IL-1 activity was associated with that of IL-1 alpha and IL-1 beta Ag. Biologically active released IL-1 was IL-1 beta. Monomeric C3b induced cell-associated IL-1 but not the release of IL-1 from monocytes. IL-1 production was also induced by stimulation of CR1 on adherent monocytes with anti-C3b receptor (CR1) antibody. The ability of multivalent C3b to induce IL-1 production could be dissociated from that of possibly contaminating LPS by several criteria including: the lack of detectable LPS in purified C3b; functional inhibition of LPS in cultures with polymyxin B; the lack of induction of extracellular IL-1 by C3b monomer; a correlation between the expression of CR1 on monocytes and the monocytic response to C3b; a dissociation between the expression of CR1, and the expression of LPS binding sites and the IL-1 response of monocytes to endotoxin. Induction of IL-1 represents a novel pathway by which C3b-CR1 interactions may modulate the immune response.

Induction of IL-1 release through stimulation of the C3b/C4b complement receptor type one (CR1, CD35) on human monocytes

Soluble polymerized human C3b and C3b bound to Sepharose induced the production of cell-associated IL-1 and the extracellular release of IL-1 activity from cultured human adherent monocytes. Cultures were performed in serum-free conditions in the presence of polymyxin B and of the PG synthesis inhibitor indomethacin. Induction of intracellular IL-1 activity was associated with that of IL-1 alpha and IL-1 beta Ag. Biologically active released IL-1 was IL-1 beta. Monomeric C3b induced cell-associated IL-1 but not the release of IL-1 from monocytes. IL-1 production was also induced by stimulation of CR1 on adherent monocytes with anti-C3b receptor (CR1) antibody. The ability of multivalent C3b to induce IL-1 production could be dissociated from that of possibly contaminating LPS by several criteria including: the lack of detectable LPS in purified C3b; functional inhibition of LPS in cultures with polymyxin B; the lack of induction of extracellular IL-1 by C3b monomer; a correlation between the expression of CR1 on monocytes and the monocytic response to C3b; a dissociation between the expression of CR1, and the expression of LPS binding sites and the IL-1 response of monocytes to endotoxin. Induction of IL-1 represents a novel pathway by which C3b-CR1 interactions may modulate the immune response.