Effects of monovalent anions of the hofmeister series on DPPC lipid bilayers Part II: modeling the perpendicular and lateral equation-of-state

The effects of Hofmeister anions on the perpendicular and lateral equation-of-state (EOS) of the dipalmitoylphosphatidylcholine lamellar phase discussed in the companion article are here examined using appropriate free energy models for the intra- and interbilayer interactions. Minimizing the free energy with respect to the two basic geometrical parameters of the lamellar phase, which are the interbilayer water thickness, d(w), and the lipid headgroup area, a(L), provides the perpendicular (osmotic pressure balance) and lateral EOS. Standard models were used for the hydration, undulation, and Van der Waals attractive force between the bilayers in the presence of electrolytes whereas two alternative treatments of electrostatic interactions were used to obtain "binding" or "partitioning" constants of anions to the lipid bilayers both in the absence and in the presence of sodium binding. The computed binding constants depend on anion type and follow the Hofmeister series, but were found to increase with electrolyte concentration, implying that the local binding approximation cannot fit bilayer repulsion data. The partitioning model was also found inadequate at high electrolyte concentrations. The fitting attempts revealed two additional features worthy of future investigation. First, at maximum swelling in the presence of electrolytes the osmotic pressure of the bilayer system cannot be set equal to zero. Second, at high salt concentrations an additional repulsion appears to come into effect in the presence of strongly adsorbing anions such as I(-) or SCN(-). Both these phenomena may reflect an inconsistent treatment of the ion-surface interactions, which have an impact on the osmotic pressure. Alternatively, they may arise from bulk solution nonidealities that cannot be handled by the classical Poisson-Boltzmann formalism. The inability of current models to explain the "lateral" EOS by fitting the area per lipid headgroup as a function of salt type and concentration shows that current understanding of phospholipid-ion interactions is still very incomplete.

[Therapeutic progress in gynecology: functional approaches]

Over the last ten years, progress in evidence-based medicine coupled with technological breakthroughs and introduction of new drugs have deeply changed the management of our patients. In the field of hormone therapy, lower dosages of estrogens and new progestins have increased tolerance and non-contraceptive benefits of oral contraceptives, while lower-doses, new progestins, new routes of administration have optimized the benefit/risk balance for the treatment of menopause. About 500,000 cycles of IVF are performed worldwide each year, optimizing male and female fertility, with less multiple pregnancies, and use of new recombinant gonadotropin, LHRH agonists/antagonists, new ovarian tissue cryopreservation techniques, etc...

Specific alkali cation effects in the transition from micelles to vesicles through salt addition

The transition of ionic micelles to vesicles with added salts is explored in this paper. The catanionic surfactant solution was comprised of sodium dodecylsulfate (SDS) and dodecyltrimethylammonium bromide (DTAB) with an excess of SDS. The micellar size increased with concentration for all salts. No anion specificity was found, probably because of the excess of SDS. However, when the cation of the added salt was varied, large differences were observed in the hydrodynamic radii of the aggregates. A classification of the cations according to their ability to increase the measured hydrodynamic radii follows a Hofmeister series. The change in aggregate size can be explained by modified counterion binding and dehydration of the surfactant headgroups.

Experimental evidence of the electrostatic contribution to the bending rigidity of charged membranes

We address the issue of the origin of the bending rigidity of a charged membrane formed from amphiphilic molecules. Electrostatic effects are investigated by direct measurement of the force necessary to deform a catanionic membrane as function of the ionic strength of the medium by means of an atomic force microscope (AFM). Using continuum mechanical modeling of membrane deformation, we derive the bending rigidity of the catanionic membranes and monitor for the first time its decrease in response to increasing salt concentration.

New natural intergenotypic (2/5) recombinant of hepatitis C virus

A 9.2-kb sequence from a hepatitis C virus (HCV) strain found in southwest France was compared to sequences from reference strains in HCV sequence databases. We found a recombinant virus with genotype 2 at the 5' end and genotype 5 at the 3' end. The crossover point was located between genes NS2 and NS3. Recombination between HCV genotypes must now be considered in studies on HCV epidemiology and evolution and in predictions of the virus response to antiviral therapy. Knowing the location of the recombination point may also be useful for constructing infectious chimeric viruses.

Determining the source of nosocomial transmission in hemodialysis units in Tunisia by sequencing NS5B and E2 sequences of HCV

Hepatitis C virus infection is a significant problem in hemodialysis units. HCV is very variable genetically with six genotypes. Clinical and epidemiological investigation of a new infection requires the determination of both the genotype and the strain of the HCV involved. A prospective, epidemiologic study of 395 dialysis patients in Tunisia was conducted from November 2001 to November 2003 to identify the source of nosocomial transmission using phylogenetic analysis of NS5b and E2 sequences. Hepatitis C infection was diagnosed by screening for anti-HCV antibodies and HCV RNA in sera using third generation ELISA and a qualitative RT-PCR assay. HCV strains were genotyped by sequencing the NS5b region. The genetic relatedness of the HCV strains was studied by sequencing the NS5b and the HVR-1 regions of the HCV genome. Two de novo cases of HCV infection were detected during the follow-up. One of them has been described previously. The case described in this study occurred in a center in which 12 patients were already infected with HCV strains belonging to genotypes 1b (n = 8) and 1a (n = 4). Phylogenetic analysis of the NS5b region from the HCV strains circulating in this center disclosed four clusters, confirmed by analysis of the HVR-1 region, providing strong evidence for nosocomial infection. Epidemiological data showed that these patients were dialyzed during the same shift and in the same area. Phylogenetic analysis of NS5b sequences is useful for determining the HCV genotype and providing evidence of nosocomial transmission.

[How I treat: an ectopic pregnancy]

Nowadays, the management of ectopic pregnancy should be codified as often as possible. Two types of treatment are possible. One surgical and the other medical. Our study is concerned with a series of 97 patients hospitalized for suspicion of ectopic pregnancy for whom the risk factors and treatment were analyzed. Our conclusion is that the medical treatment should be more frequently proposed and surgery should prefer the conservative treatment whenever it is still possible.

The hepatitis C virus epidemic in Cameroon: genetic evidence for rapid transmission between 1920 and 1960

Hepatitis C virus (HCV) infection in Cameroon is characterized by widespread seropositivity and great virus genetic diversity (3 genotypes and over 10 subtypes). A total of 244 HCV NS5B sequences of 382-405 bp long (95 type 1, 58 type 2, and 91 type 4) were phylogenetically analyzed to estimate the history of the HCV epidemic in Cameroon. The newly developed Bayesian coalescent approach was used to infer the history of each HCV type. The estimated dates of the most recent common ancestors (MRCA) for genotypes 1 (1500; 95% confidence interval (95% CI): 1300-1650) and 4 (1500; 95% CI: 1350-1700) were in the same range, while the date for genotype 2 MRCA (1600; 95% CI: 1400-1750) was slightly more recent. The mean genetic distance between HCV genotype 1 sequences was greater than that of HCV type 4 sequences, itself greater than that of HCV type 2 sequences. The initial infected populations of all three genotypes did not grow until recently, when they grew exponentially. The growth rate has now begun to slow, with a less steep exponential growth curve. The period of exponential growth of all the three genotypes was between 1920 and 1960. These results (i) confirm that HCV genotypes 1 and 4 have produced long-term endemics, (ii) suggest that genotype 2 was introduced into Cameroon more recently, and (iii) indicate that the exponential spread of the three genotypes between 1920 and 1960 coincided with the mass campaign against trypanosomiasis and mass vaccinations in Cameroon.

[What's new at the maternal-foetal interface: role of the hCG/LH-hCG receptor couple during embryo implantation]

Implantation of the embryo into the maternal endometrium represents a unique biological process, combining an immunological (tolerance of an allograft) and biological (adhesion of two epitheliums) paradox. The success of implantation depends on a receptive endometrium, a functionally normal blastocyst and a synchronized cross-talk between embryonic and maternal tissues. Though sexual steroids control the process, a cascade of growth factors or cytokines are the prime paracrine mediators of the dialogue at the maternal-embryonic interface. HCG is one of the molecules most precociously produced by the embryo and is the most specific marker of its presence. HCG is a luteotropic factor which relays the inadequate support provided by the reduced rates of LH, but also influences the pregnancy on a paracrine mode by a local action on implantation process, probably by interacting with its receptor, the LH/hCG-R that we have evidenced on endometrial epithelium. We demonstrate that embryo actively participate into its implantation, tolerance and placentation.

Scanning tunneling spectroscopy simulations of poly(3-dodecylthiophene) chains adsorbed on highly oriented pyrolytic graphite

We report on a hybrid scheme to perform efficient and accurate simulations of scanning tunneling spectroscopy (STS) of molecules weakly bonded to surfaces. Calculations are based on a tight binding (TB) technique, including a self-consistent calculation of the electronic structure of the molecule, to predict STS conductance spectra. The use of a local basis makes our model easily applicable to systems with several hundreds of atoms. We performed first-principles density-functional calculations to extract the geometrical and electronic properties of the system. In this way, we can include, in the TB scheme, the effects of structural relaxation upon adsorption on the electronic structure of the molecule. This approach is applied to the study of regioregular poly(3-dodecylthiophene) polymer chains adsorbed on highly oriented pyrolytic graphite. Results of spectroscopic calculations are discussed and compared with recently obtained experimental data.

Genetic diversity of HCV genotype 2 strains in South Western France

Hepatitis C virus (HCV) is a major cause of chronic hepatitis and liver disease worldwide. The genetic heterogeneity of HCV and its spread among infected patients can be examined accurately by nucleotide sequencing. The diversity of HCV genotype 2 strains (HCV-2) was studied in a large cohort of patients in the Midi Pyrénées area of southern France. Phylogenetic analysis was performed on 344 NS5B sequences from patients infected with HCV-2. These included 145 strains whose E2 region was also analyzed, and epidemiological data were collected for the corresponding patients. HCV-2 accounts for 11.3% of HCV infections in this area. Phylogenetic analysis of NS5B sequences revealed eight subtypes, while that of the E2 region provided congruent results for 100% of strains. The most frequent subtypes were 2i (24.7%), 2k (22.4%) 2c (17.4%), and 2a (10.8%). The mean age of HCV-2-infected patients was 55.5 years. Epidemiological data showed that blood transfusion is the major route of infection, but it was not associated with any particular subtype. By contrast, intravenous drug users were infected predominantly with genotype 2a. HCV-2a-infected patients were younger than patients infected with other subtypes (48 vs. 56.5 years, P < 0.01). This study shows substantial genetic diversity of HCV-2 subtypes in the south of France and the spread of 2a strains via intravenous drug users.

Safety of Oxygreen®, an ozone treatment on wheat grains. Part 2. Is there a substantial equivalence between Oxygreen-treated wheat grains and untreated wheat grains?

The Oxygreen process is a new process based on wheat grain treatment by ozone (produced in situ), in a closed sequential batch reactor. The Oxygreen process offers a close, homogeneous, and controlled contact between the gas and the grain. It is proposed for use for wheat grain decontamination (insects, fungi, bacteria, mycotoxins, pesticides). It takes place in classical milling diagram, and occurs after grain cleaning and before milling. The aim of the study reported here was to determine if Oxygreen treatment could induce in the grain the formation of processing-related compounds, and if these compounds are specific or could be recognized as classical modifications already used in the cereal industry (milling, baking). Studies were performed in order to evaluate any effect of Oxygreen treatment on vitamins, ferulic acid, phytates, proteins, carbohydrates, and lipids. It was concluded that there was no detectable substantial difference between ozone-treated grains and the untreated ones, although some quantitative differences can occur. The more detectable differences concern concentration of free sugars, and inhibition of some oxidative enzymes. These quantitative differences are very slight compared to the modifications that occur in dough, after addition of oxidative products directly in flour, or during kneading and dough fermentation.

Intrahepatic cytokine profile in renal-transplant patients infected by hepatitis C virus

In order to examine the immunopathogenesis of hepatitis C virus (HCV)-related liver injury in renal-transplant patients, intra-hepatic cytokine profiles were examined in 38 liver biopsies from 38 patients by measuring messenger RNA (mRNA) concentrations by a real-time PCR method of a Th1 cytokine (i.e., interferon (IFN)-gamma), a Th2 cytokines (i.e., interleukine (IL)-10), a proinflammatory cytokine (i.e., IL-8), and a potent fibrogenic factor (transforming growth factor [TGF]-beta). There was no significant difference in TGF-beta, IFN-gamma, IL-10, or IL-8 levels of expression according to liver-activity grade, liver-fibrosis stage, the concentration of HCV RNA at liver biopsies, or the HCV genotype. However, IFN-gamma/beta-actin mRNA concentration was higher than the IL-10/beta-actin mRNA concentration in patients with F3 Metavir score. Median IFN-gamma/beta-actin mRNA concentration tended to be higher in patients with A3 and A4 Metavir activity grades compared with those with A0 and A1 activity grades. There was a significant correlation between the duration of HCV infection and both TGF-beta/beta-actin (r(2)=0.19, P=0.04) and IL-8/beta-actin mRNA concentrations (r(2)=0.19, P=0.03). IFN-gamma/beta-actin mRNA concentration also increased according to the duration of HCV (r(2)=0.19, P=0.07). Finally, there was a significant correlation between the duration of HCV infection and liver fibrosis stage (r(2)=0.17, P=0.045). Intrahepatic Th1 cytokine profile seems to be predominant in patients with extensive fibrosis and activity scores, suggesting that it might be responsible for liver injury in renal transplant patients.

Safety of Oxygreen®, an ozone treatment on wheat grains.Part 1. A four-week toxicity study in rats by dietary administration of treated wheat

The Oxygreen process is a new treatment approved by The French Food Safety Authority (AFSSA) as a processing aid for flour quality improvement, based on treatment by ozone, in a closed sequential batch reactor. This treatment takes place in the classical milling sequence, after the grain-cleaning step and before milling. The Oxygreen process could also be used for its properties in wheat grain decontamination (insects, fungi, bacteria, mycotoxins, storage insecticides residues). The aim of this study was to determine if Oxygreen treatment could induce in the grain the formation of processing-related substances, able to provoke adverse effects, after ingestion of the wheat and/or derived products, and to establish the safety of the Oxygreen process for animals and consumers. A four-week toxicity study, according to OECD guideline No. 407, was performed on Dark agouti rats fed exclusively with wheat grains, treated or untreated with Oxygreen. Clinical, haematological, blood biochemical, urinary and histopathological parameters were investigated during the study. The few modifications observed in animals given treated wheat were an increase of rectal temperature in females, a slight decrease of calcium concentration in males and slight decrease of certain blood cell number without clinical significances. This work shows that wheat treated by Oxygreen does not induce adverse effects in Dark agouti rats after oral administration. Therefore wheat and derived products from wheat, after Oxygreen treatment on grain, could be considered as safe for the consumer.

Incidence of HCV infection in French hemodialysis units: a prospective study

A large prospective study was carried out from 1997 to 2000 in 25 French hemodialysis units including 1,323 patients to determine the incidence of hepatitis C virus (HCV) infection. Monthly testing of alanine aminotransferase (ALT) activity, and assessment of HCV RNA and anti-HCV antibodies if the ALT activity was elevated, identified 14 new infections in 7 different units, giving an incidence of 0.4% new HCV infections per year. Molecular analyses and epidemiological data indicated that five patients became infected with HCV outside the unit where they were dialyzed, while the nine remaining patients acquired HCV from infected patients on dialysis during the same shift at the same unit. HCV was cleared in six of the seven (85.7%) patients with acute hepatitis C who were given standard doses of alpha-interferon (alpha-IFN). The persistence of nosocomial transmission of HCV in hemodialysis units emphasizes the need to implement infection control practices. Identifying new infections is crucial because alpha-IFN treatment results in long term clearance of HCV RNA in a large proportion of patients.

Effects of systemic lupus erythematosus on spatial cognition and cerebral regional metabolic reactivity in BxSB lupus-prone mice

Brain-reactive auto-antibodies appear as key elements in the progressive CNS disturbances associated with systemic lupus erythematosus. The BxSB lupus prone mice are a model of this pathology, in which a gene located on the Y chromosome provokes a sex specific morbidity in males. This study was aimed to establish and characterize the relationships between behavioral disorders, neurological deficiencies and the aged-related immunological perturbations in this murine model. For this purpose, spatial and motor abilities were evaluated in male and female mice at six and 26 weeks of age. The results showed that the older males were greatly altered in their spatial abilities while the young ones and the females, whatever their age, were not. None of the animals had motor skill and motor learning disabilities. These spatial alterations were associated with modifications of basal neuronal activity measured by the cytochrome oxidase histochemical method in several areas directly or indirectly involved in spatial behavior, such as the hippocampus, the amygdala, the parietal and perirhinal cortex. Immunological study allowed us to correlate the behavioral abnormalities to the appearance of antibodies reactivities against cellular and nuclear components.

Evolution of Hepatitis C Virus Quasispecies during Therapy with Il2 Combinated to Alpha Interferon and Ribavirin

This study analyses the impact of interleukin 2 (IL2) combined with alpha interferon (IFN-α) and ribavirin on the heterogeneity of hepatitis C virus (HCV). We studied 10 patients who took part in a clinical trial that assessed the effects of retreatment with IL2, IFN-α and ribavirin in patients who failed to clear the virus after a previous bitherapy. The heterogeneity of HCV quasispecies was assessed by cloning and sequencing the hypervariable region 1 (HVR1) in samples obtained at baseline (W0), after 12 weeks of treatment with IFN-α and ribavirin (W12), after a cycle of administration of IL2 in combination with the classical bitherapy (W21 and W24) in the eight patients who failed to clear the virus under treatment. The mean viral load at W21 and at W24 was not different from that at W12. The heterogeneity of HVR1 quasispecies after the administration of IL2 was not different from that at baseline or after 12 weeks of bitherapy. Furthermore, the proportion of nonsynonymous substitutions was unchanged after the IL2 cycles. Thus, the efficacy of the tritherapy with IL2, IFN-α and ribavirin is similar to that of the classical bitherapy. Treatment with IL2 in combination with IFN-α and ribavirin had no effect on the selective pressure on HCV quasispecies. IL2 is not the best option to treat hepatitis C.

Galig, a novel cell death gene that encodes a mitochondrial protein promoting cytochrome c release

Galectin-3 internal gene (Galig) was recently identified as an internal gene transcribed from the second intron of the human galectin-3 gene that is implicated in cell growth, cell differentiation, and cancer development. In this study, we show that galig expression causes morphological alterations in human cells, such as cell shrinkage, cytoplasm vacuolization, nuclei condensation, and ultimately cell death. These alterations were associated with extramitochondrial release of cytochrome c, a known cell death effector. Furthermore, Bcl-xL co-transfection significantly reduced the release of cytochrome c induced by galig expression, suggesting a common pathway between the cytotoxic activity of galig and the anti-apoptotic activity of Bcl-xL. This antagonism was not observed upon co-transfection of Bcl-2 and galig. Galig encodes a mitochondrial-targeted protein named mitogaligin. Structure-activity relationship studies showed that the mitochondrial addressing of mitogaligin relies on an internal sequence that is required and sufficient for the release of cytochrome c and cell death upon cell transfection. Moreover, incubation of isolated mitochondria with peptides derived from mitogaligin induces cytochrome c release. Altogether, these results show that galig is a novel cell death gene encoding mitogaligin, a protein promoting cytochrome c release upon direct interaction with the mitochondria.