Liraglutide, a glucagon-like peptide 1 receptor agonist, exerts analgesic, anti-inflammatory and anti-degradative actions in osteoarthritis

Osteoarthritis (OA) is a common disabling disease worldwide, with no effective and safe disease-modifying drugs (DMOAD) in the market. However, studies suggest that drugs, such as liraglutide, which possess strong potential in decreasing low-grade systemic inflammation may be effective in treating OA. Therefore, the aim of this study was to examine the anti-inflammatory, analgesic, and anti-degradative effects in OA using in vitro and in vivo experiments. The results showed that intra-articular injection of liraglutide alleviated pain-related behavior in in vivo sodium monoiodoacetate OA mouse model, which was probably driven by the GLP-1R-mediated anti-inflammatory activity of liraglutide. Moreover, liraglutide treatment significantly decreased IL-6, PGE₂ and nitric oxide secretion, and the expression of inflammatory genes in vitro in chondrocytes and macrophages in a dose-dependent manner. Additionally, liraglutide shifted polarized macrophage phenotype in vitro from the pro-inflammatory M1 phenotype to the M2 anti-inflammatory phenotype. Furthermore, liraglutide exerted anti-catabolic activity by significantly decreasing the activities of metalloproteinases and aggrecanases, a family of catabolic enzymes involved in cartilage breakdown in vitro. Overall, the findings of this study showed that liraglutide ameliorated OA-associated pain, possess anti-inflammatory and analgesic properties, and could constitute a novel therapeutic candidate for OA treatment.

Targeting the GLP-1/GLP-1R axis to treat osteoarthritis: A new opportunity?

Osteoarthritis (OA) is a degenerative joint disease affecting millions of people worldwide. In OA, chondrocytes, synovial cells and other joint cells become activated when exposed to an abnormal environment, including mechanical stress, inflammatory cytokines or disorganization of matrix proteins. Several analogues of the hormones called incretins have been developed and are used notably for treating type 2 diabetes mellitus. Data has accumulated to suggest that incretinomimetics, which bind to the glucagon-like peptide-1 receptor (GLP-1R), have beneficial pleiotropic effects such as immunomodulation, anti-inflammation and neuronal protection. Thus, because of their anti-inflammatory properties, GLP-1-based therapies could benefit OA patients. This review focuses on the GLP-1R pathway, molecular mechanisms and phenotypes related to OA pathogenesis.

The translational potential of this article

The search for new therapeutic targets to treat people suffering from OA remains urgent as there is currently no disease-modifyingtherapy available for this disease. This review discusses how GLP-1 analogues could be potential DMOADs for treating OA thanks to their anti-inflammatory, immunoregulatory and differentiation properties.

Attitudes vis-à-vis du vaccin COVID-19 des soignants exerçant en Guyane française

Introduction

La Guyane française a fait face à une première vague significative l’été 2020, quelques mois après la métropole. L’étude EpiCovid a révélé que 25 % des guyanais avaient été touchés par le COVID. Les soignants, comme ailleurs, ont fait partie des populations significativement impactées par l’épidémie.

Après l’autorisation du vaccin à ARNm Comirnaty® par l’Agence européenne du médicament fin décembre, la métropole a commencé à vacciner dans les EHPAD. L’arrivée des vaccins a été retardée de 15 jours en Guyane du fait de l’attente de l’arrivée d’un congélateur à −80 °C à l’hôpital de Cayenne. Dès le début de la campagne vaccinale dans les EHPAD et auprès des soignants, des réticences vis-à-vis du vaccin ont été exprimées. La vaccination était accessible à tous les soignants de plus de 50 ans ou avec comorbidités au moment de l’enquête.

Dans le contexte de l’émergence du variant 20J/501Y.V3 en Amérique du Sud, une meilleure compréhension des attitudes et de l’intention vaccinale des professionnels de santé de ce territoire particulier est susceptible d’aider à l’ajustement de la campagne.

Matériels et méthodes

Une enquête épidémiologique transversale a été mis en place en février et mars 2021 à destination de l’ensembles des soignants de Guyane à l’aide d’un questionnaire en ligne sur le site wepi.org, diffusé par mailing larges en partenariat avec les structures de santé du territoire, les URPS et les ordres médecins et infirmiers, la lettre de l’ARS, les groupes What'sApp de professionnels, sous forme de QR code affichés et sur les fonds d’écran des ordinateurs professionnels et sur support papier dans les services du CH de Cayenne et les 17 centres délocalisés de prévention et de soins (CDPS) des communes de l’intérieur.

Résultats

Au total, 578 professionnels de santé ont répondu à l’enquête, dont 42 % de médecins ou sage femmes, 37 % d’infirmiers et 20 % d’autres professionnels de santé. Les médecins et les infirmiers exerçaient en libéral (30 % et 23 %), en milieu hospitalier (48 % et 51 %) et en CDPS (10 % et 18 %, respectivement).

Dans l’ensemble, 91 % des soignants interrogés se déclaraient favorables aux vaccinations en général, mais 26 % défavorables à certains vaccins.

Concernant la vaccination contre le COVID-19, 65 % étaient déjà vaccinés ou envisageaient probablement de se faire vacciner, 11 % étaient indécis et 24 % déclaraient ne pas vouloir se faire vacciner. L’intention vaccinale était plus élevée parmi les médecins (87 %) que parmi les infirmiers et les autres professions de santé (50 % et 46 %, p < 0,001). Le refus du vaccin n’était pas différent selon le mode d’exercice, libéral ou hospitalier. L’opposition au vaccin était plus fréquente parmi les femmes (30 %), les moins de 35 ans (37 %) et parmi les professionnels de santé originaires de Guyane et des Antilles françaises (48 %). Ces facteurs restaient associés en analyse multivariée par régression logistique. À l’inverse, parmi les professionnels originaires de métropole ou de l’étranger, elle n’était pas différente en fonction de l’ancienneté d’arrivée en Guyane (qui était en médiane de 8 ans, IIQ [19–2]). Elle ne variait pas non plus en fonction du lieu d’exercice.

Conclusion

Les intentions vaccinales des professionnels de santé de Guyane française dans la période initiale de mise à disposition des vaccins sont assez contrastées, avec près d’un soignant sur quatre ne souhaitant pas se faire vacciner.

THU0055 ANTI-DEGRADATIVE AND PRO-CHONDROGENIC PROPERTIES OF LIRAGLUTIDE, A GLUCAGON-LIKE-PEPTIDE 1 RECEPTOR AGONIST: EVIDENCE FROM PRECLINICAL STUDIES AND IMPLICATION FOR OSTEOARTHRITIS

Background:

Osteoarthritis (OA) is a degenerative joint disease affecting millions of individuals worldwide. Its development has been reported to be associated with cartilage degradation and inflammatory responses leading to pain, swelling and reduced function. Although OA is a disorder of the whole joint, the progressive destruction of cartilage extracellular matrix is considered as its hallmark. To date, approved OA treatments are only symptomatic. Therefore, there is an urgent need to explore disease-modifying OA drugs (DMOADs) that can mitigate, stop, or even reverse the development of OA.

Objectives:

In this context, the objective of this study was to assess the effect of liraglutide, a Glucagon-Like-Peptide 1 Receptor (GLP-1R) agonist approved for type 2 diabetes, on chondrogenesis, catabolism/inflammation and cartilage protection inin vitroandin vivopreclinical models of OA.

Methods:

The capacity of liraglutide to induce chondrogenesis was evaluated using primary human mesenchymal stem cells (hMSCs). Alcian blue staining was used to assess differentiation of hMSC into chondrocyte spheroids. IL-1β-stimulated mouse articular chondrocytes were treated with different concentrations of liraglutide for 24h. Production of matrix metalloproteinase MMP-13, prostaglandin E2 (PGE2) and nitrite was measured by ELISA and Griess reaction, respectively. Exendin 9-39, a GLP-1R antagonist, was used to confirm target engagement in thein vitroexperiments. Intra-articular (IA) injections of liraglutide or vehicle were performed in the type II collagenase rat model. Histopathological analyses (OARSI scores1) were conducted blindly by one investigator.

Results:

Liraglutide induced the differentiation of hMSCs into chondrocytes. Indeed, 21 days after differentiation initiation, 5/6 and 4/6 alcian-blue positive spheroids were observed for 10 and 100nM liraglutide, respectively, versus 0/6 for vehicle. Liraglutide significantly reduced dose-dependently the IL-1β-induced production of PGE2 (5808±178 for vehicle vs 4560±140, 2933±171 and 2365±85 pg/ml for liraglutide 10, 100 and 500nM, respectively, p≤0.001), nitrite (24.9±0.4 for vehicle vs 20.9±1.5, 19.1±0.9 and 16.5±0.5 µM for liraglutide 10, 100 and 500nM, respectively, p≤0.001) and MMP-13 (686±9 for vehicle vs 553±3, 402±5 and 297±8 pg/ml for liraglutide 10, 100 and 500nM, respectively, p≤0.001) in murine chondrocytes. Effects of liraglutide were GLP-1R dependent since exendin 9-39 significantly counteracted both chondrogenesis and inflammation/catabolism markers expression. Histological assessment of rat collagenase-injected knee joint revealed a significant (p≤0.05) decrease of the total joint score in the IA Liraglutide treated group (8±4) compared to vehicle (11±4).

Conclusion:

Liraglutide induced chondrogenesis, decreased metalloproteinase and inflammatory mediators production by chondrocytes and protected cartilage inin vitroandin vivopreclinical OA models, opening the way for repositioning this drug as a potential DMOAD.

References:

[1]Osteoarthritis Cartilage. 2010 Oct;18 Suppl 3:S24-34

Acknowledgments:

All the people who contributed to the InOsteo project: the members of 4P-Pharma, INSERM UMR S938 research team, SATT Lutech and Sorbonne University

Disclosure of Interests:

Francis Berenbaum Grant/research support from: TRB Chemedica (through institution), MSD (through institution), Pfizer (through institution), Consultant of: Novartis, MSD, Pfizer, Lilly, UCB, Abbvie, Roche, Servier, Sanofi-Aventis, Flexion Therapeutics, Expanscience, GSK, Biogen, Nordic, Sandoz, Regeneron, Gilead, Bone Therapeutics, Regulaxis, Peptinov, 4P Pharma, Paid instructor for: Sandoz, Speakers bureau: Novartis, MSD, Pfizer, Lilly, UCB, Abbvie, Roche, Servier, Sanofi-Aventis, Flexion Therapeutics, Expanscience, GSK, Biogen, Nordic, Sandoz, Regeneron, Gilead, Sandoz, Coralie Meurot Employee of: 4P-Pharma, Jerome Breton Employee of: 4P-Pharma, Laure Sudre: None declared, Carole Bougault: None declared, Revital Rattenbach Shareholder of: 4P-Pharma, Employee of: 4P-Pharma, Celine Martin Employee of: 4P-Pharma, Claire Jacques: None declared

New probiotic strains for inflammatory bowel disease management identified by combining in vitro and in vivo approaches

Alterations in the gut microbiota composition play a key role in the development of chronic diseases such as inflammatory bowel disease (IBD). The potential use of probiotics therefore gained attention, although outcomes were sometimes conflicting and results largely strain-dependent. The present study aimed to identify new probiotic strains that have a high potential for the management of this type of pathologies. Strains were selected from a large collection by combining different in vitro and in vivo approaches, addressing both anti-inflammatory potential and ability to improve the gut barrier function. We identified six strains with an interesting anti-inflammatory profile on peripheral blood mononuclear cells and with the ability to restore the gut barrier using a gut permeability model based on Caco-2 cells sensitized with hydrogen peroxide. The in vivo evaluation in two 2,4,6-trinitrobenzene sulfonic acid-induced murine models of colitis highlighted that some of the strains exhibited beneficial activities against acute colitis while others improved chronic colitis. Bifidobacterium bifidum PI22, the strain that exhibited the most protective capacities against acute colitis was only slightly efficacious against chronic colitis, while Bifidobacterium lactis LA804 which was less efficacious in the acute model was the most protective against chronic colitis. Lactobacillus helveticus PI5 was not anti-inflammatory in vitro but the best in strengthening the epithelial barrier and as such able to significantly dampen murine acute colitis. Interestingly, Lactobacillus salivarius LA307 protected mice significantly against both types of colitis. This work provides crucial clues for selecting the best strains for more efficacious therapeutic approaches in the management of chronic inflammatory diseases. The strategy employed allowed us to identify four strains with different characteristics and a high potential for the management of inflammatory diseases, such as IBD.

PBX1 haploinsufficiency leads to syndromic congenital anomalies of the kidney and urinary tract (CAKUT) in humans

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) represent a significant healthcare burden since it is the primary cause of chronic kidney in children. CNVs represent a recurrent molecular cause of CAKUT but the culprit gene remains often elusive. Our study aimed to define the gene responsible for CAKUT in patients with an 1q23.3q24.1 microdeletion.

METHODS

We describe eight patients presenting with CAKUT carrying an 1q23.3q24.1 microdeletion as identified by chromosomal microarray analysis (CMA). Clinical features were collected, especially the renal and urinary tract phenotype, and extrarenal features. We characterised PBX1 expression and localisation in fetal and adult kidneys using quantitative RT-PCR and immunohistochemistry.

RESULTS

We defined a 276-kb minimal common region (MCR) that only overlaps with the PBX1 gene. All eight patients presented with syndromic CAKUT. CAKUT were mostly bilateral renal hypoplasia (75%). The most frequent extrarenal symptoms were developmental delay and ear malformations. We demonstrate that PBX1 is strongly expressed in fetal kidneys and brain and expression levels decreased in adult samples. In control fetal kidneys, PBX1 was localised in nuclei of medullary, interstitial and mesenchymal cells, whereas it was present in endothelial cells in adult kidneys.

CONCLUSIONS

Our results indicate that PBX1 haploinsufficiency leads to syndromic CAKUT as supported by the Pbx1-null mice model. Correct PBX1 dosage appears to be critical for normal nephrogenesis and seems important for brain development in humans. CMA should be recommended in cases of fetal renal anomalies to improve genetic counselling and pregnancy management.

Chronic delivery of α-melanocyte-stimulating hormone in rat hypothalamus using albumin-alginate microparticles: effects on food intake and body weight

Chronic delivery of neuropeptides in the brain is a useful experimental approach to study their long-term effects on various biological parameters. In this work, we tested albumin-alginate microparticles, as a potential delivery system, to study if continuous release in the hypothalamus of α-melanocyte-stimulating hormone (α-MSH), an anorexigenic neuropeptide, may result in a long-term decrease in food intake and body weight. The 2-week release of α-MSH from peptide-loaded particles was confirmed by an in vitro assay. Then, daily food intake and body weight were studied for 18 days in rats injected bilaterally into the paraventricular hypothalamic nucleus with particles loaded or not with α-MSH. A decrease in body weight gain, persisting throughout the study, was found in rats injected with α-MSH-charged particles as compared with rats receiving non-charged particles and with rats injected with the same dose of α-MSH in solution. Food intake was significantly decreased for 3 days in rats receiving α-MSH-loaded particles and it was not followed by the feeding rebound effect which appears after food restriction. The presence of α-MSH-loaded particles in the hypothalamus was confirmed by immunohistochemistry. In conclusion, our study validates albumin-alginate microparticles as a new carrier system for long-term delivery of neuropeptides in the brain and demonstrates that chronic delivery of α-MSH in the hypothalamus results in a prolonged suppression of food intake and a decrease of body weight gain in rats.

Radiation-mediated formation of complex damage to DNA: a chemical aspect overview

During the last three decades, a considerable amount of work has been undertaken to determine the nature, the mechanism of formation and the biological consequences of radiation-induced DNA lesions. Most of the information was obtained via the development of chemical approaches, including theoretical, analytical and organic synthesis methods. Since it is not possible to present all the results obtained in this review article, we will focus on recent data dealing with the formation of complex DNA lesions produced by a single oxidation event, as these lesions may play a significant role in cellular responses to ionizing radiation and also to other sources of oxidative stress. Through the description of specific results, the contribution of different chemical disciplines in the assessment of the structure, the identification of the mechanism of formation and the biological impacts in terms of repair and mutagenicity of these complex radiation-induced DNA lesions will be highlighted.

Genotype identification of Enterocytozoon bieneusi isolates from stool samples of HIV-infected Tunisian patients

The microsporidian species Enterocytozoon bieneusi is a major cause of chronic diarrhea and malabsorption in patients with AIDS. Genotyping was performed on seven E. bieneusi strains for the first time in Tunisia. All the strains were isolated from stool samples of humans with immunodeficiency virus (HIV) infection. Analysis of the ribosomal RNA gene internal transcribed spacer (rDNA ITS) allowed the identification of three distinct genotypes previously described in other studies. Genotypes D and B were characterized in four and two respectively. The Peruvian genotype (Peru 8) was detected in the last isolate. These results indicate a genetic diversity in E. bieneusi strains from HIV Tunisian patients and suggest the coexistence of both zoonotic and anthroponotic route of transmission.

Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria

The IR spectra of the bacteriochlorophyll a and b cations and the bacteriopheophytin a and b anions were obtained by using an IR and optically transparent electrochemical cell. Prominent effects of radical formation on the vibrational spectra were found for bands assigned to the ester, keto, and acetyl C=O groups and for vibrations from macrocycle bonds. The (radical-minus-neutral) difference spectra are compared to the light-induced difference spectra of the primary donor photooxidation and the intermediary acceptor photoreduction in the reaction center of photosynthetic bacteria. Light-induced absorbance changes from bacteriochlorophyll a-containing reaction centers bear striking similarities to the electrochemically induced absorbance changes observed upon formation of bacteriochlorophyll a(+)in vitro. Comparison of the radical formation in vitro in a hydrogen-bonding or a nonhydrogen-bonding solvent suggests an ester C=O group hydrogen bonded in the neutral state but free in the cation state. For the keto C=O group, the same comparison indicates one free carbonyl group. The (anion-minus-neutral) difference spectra of bacteriopheophytin a and b exhibit a single band in the ester C=O frequency range. In contrast, two bands are observed in the difference spectra of the intermediary acceptor reduction in the reaction center of Rhodopseudomonas viridis. The higher frequency band exhibits a sensitivity to (1)H-(2)H exchange, which suggests a contribution from a protonated carboxyl group of an amino acid side chain.

Femtosecond spectroscopy of electron transfer in the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides R-26: Direct electron transfer from the dimeric bacteriochlorophyll primary donor to the bacteriopheophytin acceptor with a time constant of 2.8 +/- 0.2 psec

The primary light-induced charge separation in reaction centers from Rhodopseudomonas sphaeroides R-26 has been investigated after excitation with laser pulses of 150 fsec duration within the longwave absorption band of the primary donor at 850 nm. An excited state of the primary donor, characterized by a broad absorption spectrum extending over the whole spectral range investigated (545-1240 nm), appeared within 100 fsec and gave rise to stimulated emission in the 870- to 1000-nm region with a 2.8-psec lifetime. The photooxidation of the primary donor, as measured at 1240 nm, and the photoreduction of the bacteriopheophytin acceptor, monitored at 545 nm and 675 nm, have been found to proceed simultaneously with a time constant of 2.8 +/- 0.2 psec. Kinetics of absorbance changes at other probe wavelengths gave no indication that an accessory bacteriochlorophyll is involved as a transient electron acceptor.

Femtosecond spectroscopy of excitation energy transfer and initial charge separation in the reaction center of the photosynthetic bacterium Rhodopseudomonas viridis

Reaction centers from the photosynthetic bacterium Rhodopseudomonas viridis have been excited within the near-infrared absorption bands of the dimeric primary donor (P), of the "accessory" bacteriochlorophylls (B), and of the bacteriopheophytins (H) by using laser pulses of 150-fsec duration. The transfer of excitation energy between H, B, and P occurs in slightly less than 100 fsec and leads to the ultrafast formation of an excited state of P. This state is characterized by a broad absorption spectrum and exhibits stimulated emission. It decays in 2.8 +/- 0.2 psec with the simultaneous oxidation of the primary donor and reduction of the bacteriopheophytin acceptor, which have been monitored at 545, 675, 815, 830, and 1310 nm. Although a transient bleaching relaxing in 400 +/- 100 fsec is specifically observed upon excitation and observation in the 830-nm absorption band, we have found no indication that an accessory bacteriochlorophyll is involved as a resolvable intermediary acceptor in the primary electron transfer process.

Excitation trapping and primary charge stabilization in Rhodopseudomonas viridis cells, measured electrically with picosecond resolution

The transmembrane primary charge separation in the photosynthetic bacterium Rhodopseudomonas viridis was monitored by electric measurements of the light-gradient type [Trissl, H. W. & Kunze, U. (1985) Biochim. Biophys. Acta 806, 136-144]. Excitation of whole cells with 30-ps laser pulses at either 532 nm or 1064 nm gave rise to a biphasic increase of the photovoltage. The fast phase, contributing about 50% of the total, rose with an exponential time constant </=40 ps and was independent of the redox state of the quinone electron acceptor. It is assigned to the migration of the excitation energy in the antenna and its subsequent trapping by the reaction center, monitored by the ultrafast charge separation between the primary electron donor and the bacteriopheophytin intermediary acceptor. The slower phase (125 +/- 50 ps) only occurred when the quinone was oxidized and disappeared when it was reduced (either chemically or photochemically). It is assigned to the forward electron transfer from the bacteriopheophytin to the quinone. The relative amplitudes of these two electrogenic steps demonstrate that the bacteriopheophytin intermediary acceptor is located halfway between the primary donor and the quinone.

Dissipative structures in a two-cell system: Numerical and experimental approaches

It has been shown that the coupling between the photoreduction of the oxidized form of dichloroindophenol (an artificial electron acceptor) by thylakoids and the incident light intensity can lead to the appearance of multiple steady states when the system is operated under open conditions. In the present work, a numerical study and experimental evidence are presented on the occurrence of dissipative structures in an arrangement of two continuously stirred tank reactors with mutual mass exchange of dichloroindophenol through an inert membrane. The stable spatial structures are generated by the creation of transient internal and external asymmetries. A nontrivial hysteresis effect between symmetric and asymmetric stable steady states has been observed.

Further characterization of protein secondary structures in purple membrane by circular dichroism and polarized infrared spectroscopies

The conformation and the orientation of the protein secondary structures in purple membrane was analyzed by infrared absorption and linear dichroism of oriented membranes as well as by UV circular dichroism of bacteriorhodopsin in intact purple membrane and in lipid vesicles. A large amount (74 +/- 5%) of transmembrane alpha-helices is detected with no significant contribution of beta-sheet strands running perpendicular to the membrane plane. Thus, these data do not support the recent structural model proposed by Jap et al. (Biophys. J. 1983, 43:81-89).

The dependence of the shapes of fluorescence induction curves in chloroplasts on the duration of illumination pulses

The shapes of fluorescence induction curves in spinach chloroplasts, measured using double-flash pump-probe techniques, are shown to depend on the duration of the actinic flashes. For flash durations tau(0) </= 2 mus, the variable fluorescence F(nu) grows exponentially (or nearly so) with increasing fluence J of the actinic pulses and the fluorescence induction ratio R = F(max)/F(0) is </=2.6. When tau(o) >/= 50 mus, the shapes of the F(nu) vs. J curves are sigmoidal, and R > 3.2. Overall, the experimentally observed trends suggest that, as the duration tau(0) of the actinic pulses is increased, the degree of sigmoidicity, the deduced values of the interunit excitation transfer parameter p, and the fluorescence induction ratios R, also tend to increase. These results can be accounted for in terms of a simple double-photon hit model in which a dark lag time tau(1) = 0.4-10 mus between the two hits is necessary for the observance of sigmoidal fluorescence induction curves and relatively high R ratios. It is shown that, in principle, such a model can account for the exponential and sigmoidal shapes of the fluorescence induction curves either within the context of a lake model of the photosynthetic antenna bed (free transfer of excitation between photosynthetic units) or the isolated (puddle) model of photosystem II reaction centers. However, from the known values of the R ratio measured with actinic pulses of different durations, or under continuous illumination, the lake model offers a better description of the experimental phenomena than the puddle model.

Geometry for the Primary Electron Donor and the Bacteriopheophytin Acceptor in Rhodopseudomonas viridis Photosynthetic Reaction Centers

The tetrapyrrole electron donors and acceptors (bacteriochlorophyll, BCh; bacteriopheophytin, BPh) within the bacterial photosynthetic reaction center (RC) are arranged with a specific geometry that permits rapid (picosecond time scale) electron tunneling to occur between them. Here we have measured the angle between the molecular planes of the bacteriochlorophyll dimer (primary donor), B(2), and the acceptor bacteriopheophytin, H, by analyzing the dichroism of the absorption change associated with H reduction, formed by photoselection with RCs of Rhodopseudomonas viridis. This angle between molecular planes is found to be 60 degrees +/- 2. This means that the ultrafast electron tunneling must occur between donors and acceptors that are fixed by the protein to have a noncoplanar alignment. Nearly perpendicular alignments have been determined for other electron tunneling complexes involving RCs. These geometries can be contrasted with models proposed for heme-heme electron transfer complexes, which have emphasized that mutually parallel orientations should permit the most kinetically facile transfers.

The treatment of cheese whey wastewater by sequential anaerobic and aerobic steps in a single digester at pilot scale

The treatment of reconstituted whey wastewater was performed in a 400 L digester at 20 degrees C, with an anaerobic digestion step, followed by a step of aerobic treatment at low oxygen concentration in the same digester. In a first set of 48 cycles, total cycle time (T(C)) of 2, 3 and 4 days were tested at varying organic loading rates (OLR). The COD removal reached 89+/-4, 97+/-3 and 98+/-2% at T(C) of 2, 3 and 4 days and OLR of 0.56, 1.04 and 0.78 g COD L(-1) d(-1), respectively. The activity of the biomass decreased for the methanogenic population, while increasing by 400% for the acidogens, demonstrating a displacement in the predominant trophic group in the biomass bed. A second set of 16 cycles was performed with higher soluble oxygen concentration in the bulk liquid (0.5 mg L(-1)) during the aerobic treatment at a T(C) of 2 days and an OLR of 1.55 g COD L(-1) d(-1), with a soluble COD removal of 88+/-3%. The biomass specific activities showed a compartmentalization of the trophic group with methanogenic activity maintained in the biomass bed and a high acidogenic activity in the suspended flocs.

A microarray to measure repair of damaged plasmids by cell lysates

DNA repair mechanisms constitute major defences against agents that cause cancer, degenerative disease and aging. Different repair systems cooperate to maintain the integrity of genetic information. Investigations of DNA repair involvement in human pathology require an efficient tool that takes into account the variety and complexity of repair systems. We have developed a highly sensitive damaged plasmid microarray to quantify cell lysate excision/synthesis (ES) capacities using small amounts of proteins. This microsystem is based on efficient immobilization and conservation on hydrogel coated glass slides of plasmid DNA damaged with a panel of genotoxic agents. Fluorescent signals are generated from incorporation of labelled dNTPs by DNA excision-repair synthesis mechanisms at plasmid sites. Highly precise DNA repair phenotypes i.e. simultaneous quantitative measures of ES capacities toward seven lesions repaired by distinct repair pathways, are obtained. Applied to the characterization of xeroderma pigmentosum (XP) cells at basal level and in response to a low dose of UVB irradiation, the assay showed the multifunctional role of different XP proteins in cell protection against all types of damage. On the other hand, measurement of the ES of peripheral blood mononuclear cells from six donors revealed significant diversity between individuals. Our results illustrate the power of such a parallelized approach with high potential for several applications including the discovery of new cancer biomarkers and the screening of chemical agents modulating DNA repair systems.

Charge separation and energy transfer in the photosystem II core complex studied by femtosecond midinfrared spectroscopy

The core of photosystem II (PSII) of green plants contains the reaction center (RC) proteins D1D2-cytb559 and two core antennas CP43 and CP47. We have used time-resolved visible pump/midinfrared probe spectroscopy in the region between 1600 and 1800 cm(-1) to study the energy transfer and charge separation events within PSII cores. The absorption difference spectra in the region of the keto and ester chlorophyll modes show spectral evolution with time constants of 3 ps, 27 ps, 200 ps, and 2 ns. Comparison of infrared (IR) difference spectra obtained for the isolated antennas CP43 and CP47 and the D1D2-RC with those measured for the PSII core allowed us to identify the features specific for each of the PSII core components. From the presence of the CP43 and CP47 specific features in the spectra up to time delays of 20-30 ps, we conclude that the main part of the energy transfer from the antennas to the RC occurs on this timescale. Direct excitation of the pigments in the RC evolution associated difference spectra to radical pair formation of PD1+PheoD1- on the same timescale as multi-excitation annihilation and excited state equilibration within the antennas CP43 and CP47, which occur within approximately 1-3 ps. The formation of the earlier radical pair ChlD1+PheoD1-, as identified in isolated D1D2 complexes with time-resolved mid-IR spectroscopy is not observed in the current data, probably because of its relatively low concentration. Relaxation of the state PD1+PheoD1-, caused by a drop in free energy, occurs in 200 ps in closed cores. We conclude that the kinetic model proposed earlier for the energy and electron transfer dynamics within the D1D2-RC, plus two slowly energy-transferring antennas C43 and CP47 explain the complex excited state and charge separation dynamics in the PSII core very well. We further show that the time-resolved IR-difference spectrum of PD1+PheoD1- as observed in PSII cores is virtually identical to that observed in the isolated D1D2-RC complex of PSII, demonstrating that the local structure of the primary reactants has remained intact in the isolated D1D2 complex.

Randomized phase II study of gemcitabine-oxaliplatin or gemcitabine-cisplatin in chemonaive patients with advanced non-small cell lung cancer (NSCLC)-CLEO 05

7097

Background: Gemcitabine-cisplatin is one of the reference doublets used in NSCLC. Oxaliplatin is a platin analog which offers a promising efficacy/tolerance profile in NSCLC. The combination of gemcitabine and oxaliplatin has been proven feasible and active in solid tumors. Methods: Patients with chemonaive, measurable, PS 0 or 1, stage IIIB/ IV NSCLC were randomized to receive either gemcitabine 1,250 mg/m2 day 1 & 8 plus oxaliplatin 130 mg/m2 day 1 (GEMOX) or gemcitabine 1,250 mg/m2 day 1 & 8 plus cisplatin 80 mg/m2day 1 (GEMCIS). Cycles were given every 3 weeks. The primary endpoint of the study was the response rate according to the RECIST criteria. Secondary endpoints included tolerance, survival and quality of life. Results: Between October 2003 and December 2004, 130 patients (66 in GEMOX and 64 in GEMCIS) were accrued at 12 centres. Baseline patient characteristics were similar in the 2 groups. Mean age was 61. There were 96 males and 34 females; 27% of patients were PS 0 and 73% were PS 1; 15% had stage IIIB and 85% had stage IV. Median number of cycles was 5 in each group. Objective response rates were 36% in GEMOX (CI 95%: 25%-50%) and 39% in GEMCIS (CI 95%: 28%-54%) respectively. Time to progression was 173 days in the GEMOX group and 163 days in the GEMCIS group. Median survival was 10.8 months in the GEMOX group and 10.4 months in the GEMCIS group. Grade III/IV neutropenia was observed in 38% of patients after GEMOX and 41% after GEMCIS; thrombocytopenia was observed in 40% and 33% of cases respectively. Grade 2+ neurotoxicity was more frequent after GEMOX (18% vs 3%). Conclusions: GEMOX has an activity comparable to GEMCIS and may be an alternative for those patients with advanced NSCLC who have a contra-indication to cisplatin.

[Table: see text]

Cohort KBP-2000-CPHG: Evaluation of prognosis factors for survival in primary bronchial cancer (PBC)

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Background: PBC has a guarded prognosis despite advances in treatment. The main epidemiologic changes observed during the last fifteen years are the strong progression in its incidence in women and the increase in adenocarcinomas. A prospective study of overall survival and survival according to sex and prognosis factors was set up from the cohort of study KBP-2000-CPHG. Methods: KBP-2000-CPHG is a prospective epidemiological study conducted throughout the year 2000 on histologically confirmed PBC patients treated in general hospitals. 5,667 patients were included. A survival study based on patient outcomes was launched between September 2004 and March 2005 in 137 centres. Each centre had to provide information on the vital status of its patients with, in the event of death, the date and cause. In the absence of vital status data, a graduated tracing strategy was set up including the interrogation of various files: city hall of the place of birth,etc. Results: 135 investigator centres out of the 137 initial centres took part. The 2 non-participating centres represented 56 patients. The vital status could be defined for 5441 of the other 5611 patients (97.0%). 88.4% of these patients had died (average time between inclusion and death: 10.5–10.7 months). In univariate study, survival status is linked with age (p < 0.0001), tobacco consumption (p < 0.0001), performance status (p < 0.0001), cancer type (small versus non small cell lung cancer-NSCLC: p < 0.0001) and for the NSCLC, with histological type (p < 0.0001) and TNM stage (p < 0.0001). According to multivariate analysis, survival status is related to age, performance status, cancer type and among the NSCLC, to age, sex, performance status, histological type and TNM stage. Conclusions: The survival study on PBC is the first one in France, including more than 5,400 patients. The first results show the prognosis role of age, sex, histological type, performance status and TNM stage.

No significant financial relationships to disclose.

Screening of TP53 mutations by DHPLC and sequencing in brain tumours from patients with an occupational exposure to pesticides or organic solvents

The aetiology of brain tumours remains unclear. Occupational exposures to pesticides and organic solvents are suspected risk factors. The case-control study CEREPHY (221 cases, 442 controls) carried in the Departement de la Gironde in France revealed a significantly increased risk of brain tumours for subjects most exposed to pesticides. In some cancers, TP53 mutations could reflect exposure to specific carcinogens. These mutations are present in approximately 30% of astrocytic brain tumours. In a pilot study, we explored the hypothesis that pesticide or solvent exposure could raise the frequency of TP53 mutations in brain tumour cells. We investigated TP53 mutations in exons 2-11 by denaturing high performance liquid chromatography (DHPLC) and sequencing, and p53 accumulation by immunohistochemistry in brain tumour of the 30 patients from CEREPHY study with a history of occupational exposure to pesticides (n = 21) and/or organic solvents (n = 14) for whom tumoral tissue was available. Included cases concerned 27% of CEREPHY cases exposed to pesticides and, based on the cumulative index of occupational exposure, they were more exposed to pesticides. There were 12 gliomas, 6 meningiomas, 7 neurinomas, 2 central nervous system lymphomas and 3 tumours of other histological types. We detected TP53 mutations in three tumours, which is similar to the expected number (3.3) calculated from 46 published studies referenced in the IARC TP53 mutations database, taking into account histological types. Considering TP53 mutations previously detected in the laboratory by DHPLC and the frequency of TP53 polymorphisms detected in this sample (similar to published data), the TP53 mutations rate is probably not underestimated. These preliminary results, even if it was on a limited number of tumours, are not in favour of the role of pesticide or organic solvent exposure in the occurrence of TP53 mutations in brain tumours.

Characterization by FTIR spectroscopy of the photoreduction of the primary quinone acceptor QA in photosystem II

Molecular changes associated with the photoreduction of the primary quinone acceptor Qa of photosystem II have been characterized by Fourier transform infrared spectroscopy. This reaction was light-induced at room temperature on photosystem II membranes in the presence of hydroxylamine and diuron. A positive signal at 1478 cm-1 is assigned to the C---O stretching mode of the semiquinone anion, and can be correlated to the negative C=O mode(s) of the neutral QA at 1645 cm-1 and/or 16 cm-1. Analogies with bacterial reaction center are found in the amide I absorption range at 1672 cm-1, 1653 cm-1 and 1630 cm-1. The stabilization of QA- does not result from a large protein conformation change, but involves perturbations of several amino acid vibrations. At 1658 cm-1, a negative feature sensitive to 1H-2H exchange is tentatively assigned to a NH2 histidine mode, while tryptophan D2252 could contribute to the signal at 1560/1550 cm-1.

A theoretical model of the photoabsorption spectra of carbon buckyonions

A theoretical model has been developed to predict the photoabsorption spectra of spherical carbon buckyonions in the region dominated by the pi-plasmon feature. This model makes use of the microscopic electronic structure of the system, which is provided by an effective Huckel one-electron model. The important screening effects are treated within the random phase approximation, whose form is an extension to the dynamic case of the one derived in a previous work for the static polarizabilities of these species. A systematic analysis as a function of the buckyonion size is performed. We compare the spectra obtained in this way with those derived from a different representation of the electron motion, namely a two-dimensional spherical electron gas, and from a classical dielectric model.

Oral vinorelbine in combination with cisplatin: a novel active regimen in advanced non-small-cell lung cancer

BACKGROUND

A phase II trial of alternating i.v. and oral vinorelbine in combination with cisplatin was designed to determine the response rate, safety profile, progression-free survival, overall survival and quality of life (QoL) in advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Fifty-six chemotherapy-naïve patients received cisplatin 100 mg/m(2) and i.v. vinorelbine 25 mg/m(2) on day 1, followed by oral vinorelbine 60 mg/m(2) on days 8, 15 and 22, every 28 days.

RESULTS

After an independent review, the response rate was 33% [95% confidence interval (CI) 20% to 46%]. Median progression-free and overall survival were 5.5 months (95% CI 3.7-6.4) and 8.9 months (95% CI 8.8-11.7), respectively. The most frequent hematological toxicities were neutropenia (grade 3-4 in 73% of patients) and anemia (grade 3-4 in 11% of patients). Grade 3-4 infections and non-hematological toxicities occurred occasionally. QoL for lung cancer related symptoms was stable or improved.

CONCLUSIONS

The efficacy and safety of the alternating vinorelbine schedule (i.v. on day 1, oral on days 8, 15 and 22) in combination with cisplatin in advanced NSCLC are similar to those of the standard regimen using exclusively i.v. vinorelbine, whereas ease of administration and patient comfort may favor the novel approach.