GSURE criterion for unsupervised regularized reconstruction in tomographic diffractive microscopy.

We propose an unsupervised regularized inversion method for reconstruction of the 3D refractive index map of a sample in tomographic diffractive microscopy. It is based on the minimization of the generalized Stein's unbiased risk estimator (GSURE) to automatically estimate optimal values for the hyperparameters of one or several regularization terms (sparsity, edge-preserving smoothness, total variation). We evaluate the performance of our approach on simulated and experimental limited-view data. Our results show that GSURE is an efficient criterion to find suitable regularization weights, which is a critical task, particularly in the context of reducing the amount of required data to allow faster yet efficient acquisitions and reconstructions.

Maternal consumption of quinine-containing sodas may induce G6PD crises in breastfed children.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzyme defect often presenting with neonatal jaundice and/or hemolytic anemia. G6PD hemolytic events are linked with exposure to a pro-oxidant agent. We here report three cases of initial G6PD crises in breastfed children secondary to maternal consumption of a tonic drink which contains quinine. Quinine was found in breast milk of one of the mothers after she consumed tonic water. CONCLUSION: The amount of quinine that is transmitted through breast milk appears to be sufficient to induce G6PD crises in breastfed children. We hence recommend that consumption of quinine-containing sodas during breastfeeding should be avoided in populations with a high prevalence of G6PD deficiency. What is Known: • G6PD hemolytic events are linked with exposure to a pro-oxidant agent. • Ingestion of fava beans by a mother who was breastfeeding has been reported to induce a neonatal G6PD crisis. What is New: • Maternal consumption of tonic drink which contains quinine appears to be sufficient to induce G6PD crises in breastfed children. • Maternal consumption of quinine-containing sodas during breastfeeding should be avoided in populations with a high prevalence of G6PD deficiency.

Reaction of the m-THPC triplet state with the antioxidant Trolox and the anesthetic Propofol: modulation of photosensitization mechanisms relevant to photodynamic therapy?

Antioxidants may affect the outcome of photodynamic therapy (PDT) through the inactivation of reactive oxygen species. Their direct interaction with photosensitizers excited at the triplet state is also worthy of interest. This process is investigated by laser flash photolysis of m-THPC (meso-tetra(3-hydroxyphenyl)chlorin, Foscan) hydroalcoholic solutions added with Trolox (TrOH), a standard antioxidant or Propofol (PfOH, Diprivan(®)), a common anesthetic agent also characterized for its antioxidant properties. Transient UV-visible absorption spectra, kinetics at selected wavelengths and final spectra after extensive laser irradiation show that both compounds react with the m-THPC triplet state, (3)m-THPC, to ultimately restore the photosensitizer in its ground state. For PfOH, this process mainly appears as a single step obeying pseudo-first order kinetics. The bimolecular rate constant for the quenching of (3)m-THPC by PfOH is around 2 × 10(6) M(-1) s(-1), a value increased to some extent by the water content of the solution. A bimolecular reaction between (3)m-THPC and TrOH is observed with a rate constant of similar magnitude and dependence upon water. However, the reaction leads, at least partly, to intermediate species assigned to the TrO˙ radical and the m-THPC anion radical. Within a few ms, these species back react to yield m-THPC in its ground state. A general mechanism involving an intermediate activated complex with some charge transfer character is proposed. Depending on the redox potentials for the oxidation of the antioxidant, this complex evolves predominantly either toward the formation of radicals (TrOH) or back to the photosensitizer ground state (PfOH). Notably, the kinetics data suggest that Propofol may quench (3)m-THPC at concentrations relevant of clinical situation in PDT involving anesthesia.

The CONSTANCES Cohort Biobank: An Open Tool for Research in Epidemiology and Prevention of Diseases.

"General-purpose cohorts" in epidemiology and public health are designed to cover a broad scope of determinants and outcomes, in order to answer several research questions, including those not defined at study inception. In this context, the general objective of the CONSTANCES project is to set up a large population-based cohort that will contribute to the development of epidemiological research by hosting ancillary projects on a wide range of scientific domains, and to provide public health information. CONSTANCES was designed as a randomly selected sample of French adults aged 18-69 years at study inception; 202,045 subjects were included over an 8-year period. At inclusion, the selected participants are invited to attend one of the 24 participating Health Prevention Centers (HPCs) for a comprehensive health examination. The follow-up includes a yearly self-administered questionnaire, and a periodic visit to an HPC. Procedures have been developed to use the national healthcare databases to allow identification and validation of diseases over the follow-up. The biological collection (serum, lithium heparinized plasma, EDTA plasma, urine and buffy coat) began gradually in June 2018. At the end of the inclusions, specimens from 83,000 donors will have been collected. Specimens are collected according to a standardized protocol, identical in all recruitment centers. All operations relating to bio-banking have been entrusted by Inserm to the Integrated Biobank of Luxembourg (IBBL). A quality management system has been put in place. Particular attention has been paid to the traceability of all operations. The nature of the biological samples stored has been deliberately limited due to the economic and organizational constraints of the inclusion centers. Some research works may require specific collection conditions, and can be developed on request for a limited number of subjects and in specially trained centers. The biological specimens that are collected will allow for a large spectrum of biomarkers studies and genetic and epigenetic markers through candidate or agnostic approaches. By linking the extensive data on personal, lifestyle, environmental, occupational and social factors with the biomarker data, the CONSTANCES cohort offers the opportunity to study the interplays between these factors using an integrative approach and state-of-the-art methods.

Prognosis of stage II colon cancer by non-neoplastic mucosa gene expression profiling.

We have assessed the possibility to build a prognosis predictor (PP), based on non-neoplastic mucosa microarray gene expression measures, for stage II colon cancer patients. Non-neoplastic colonic mucosa mRNA samples from 24 patients (10 with a metachronous metastasis, 14 with no recurrence) were profiled using the Affymetrix HGU133A GeneChip. Patients were repeatedly and randomly divided into 1000 training sets (TSs) of size 16 and validation sets (VS) of size 8. For each TS/VS split, a 70-gene PP, identified on the TS by selecting the 70 most differentially expressed genes and applying diagonal linear discriminant analysis, was used to predict the prognoses of VS patients. Mean prognosis prediction performances of the 70-gene PP were 81.8% for accuracy, 73.0% for sensitivity and 87.1% for specificity. Informative genes suggested branching signal-transduction pathways with possible extensive networks between individual pathways. They also included genes coding for proteins involved in immune surveillance. In conclusion, our study suggests that one can build an accurate PP for stage II colon cancer patients, based on non-neoplastic mucosa microarray gene expression measures.

Reactivity towards singlet oxygen of propofol inside liposomes and neuronal cells.

Singlet oxygen (1O2), a reactive oxygen species, has been found to be implicated in many cellular events and pathological disorders. Herein, we investigated the reactivity of 1O2 towards the anaesthetic agent propofol (PPF) encapsulated within DMPC liposomes. By time resolved luminescence, the rate constant of 1O2 quenching by PPF was evaluated, depending on the location of the sensitizer, with following values: 1.35+/-0.05x10(7) M(-1) s(-1) for deuteroporphyrin (as embedded source) and 0.8+/-0.04x10(7) M(-1) s(-1) for uroporphyrin (as external source), respectively. The nature of the oxidation product, resulting from the reaction of 1O2 with PPF, was determined using absorption and HPLC techniques. Finally, the in vitro protective effect of PPF towards the 1O2-induced neuronal cell toxicity was evaluated in terms of cell viability.

Kinetics of the interactions of a dicarboxylic porphyrin with unilamellar lipidic vesicles: interplay between bilayer thickness and pH in rate control.

The transfer of a dicarboxylic porphyrin from phosphatidylcholine fluid-phase unilamellar vesicles towards albumin is studied focusing on bilayer thickness and pH effects. The kinetics of this process yield the rate constants for the porphyrin flip-flop from the inner to the outer hemileaflet and its exit towards aqueous medium. Phospholipids with monounsaturated 14-22 carbon chains are used. Interplay between bilayer thickness and pH for the control of the rate constants is observed. This results in the amplification, at physiological pH, of the effect of membrane thickness on the flip-flop and exit rates as compared to pH 8.5 and 6.5. These data are explained by the degree of porphyrin burying within the bilayer resulting from a compromise between favorable hydrophobic interactions with the hydrocarbon phase and unfavorable penetration of the polar carboxylic chains. The balance between the two effects depends particularly on the neutralization of one carboxylic chain. Considering the bilayer hydrophobicity profile and the porphyrin size, the optimization of hydrophobic interactions appears dependent on the bilayer thickness. The flip-flop and the exit are governed by neutralization and deprotonation of the carboxylic chains, respectively, the rate of these proton exchanges being dependent on the porphyrin location within the bilayer.

Kinetics of incorporation of porphyrins into small unilamellar vesicles.

The kinetics of hematoporphyrin or deuteroporphyrin incorporation in egg phosphatidylcholine small unilamellar vesicles have been investigated by fluorescence stopped-flow measurements. The processes can be described by a fast equilibrium. The on-rate constant is nearly diffusion controlled regardless of the compound used and the pH. The affinity of these porphyrins for the vesicles is merely governed by the exit rate which depends on the structure of the porphyrin and on its charge determined by pH.

Kinetic and equilibrium studies of incorporation of di-sulfonated aluminum phthalocyanine into unilamellar vesicles.

The interactions of cis-di-sulfonated aluminum phthalocyanine (PcS(2)Al) with dimyristoylphosphatidylcholine (DMPC) unilamellar vesicles have been investigated by fluorescence spectroscopy. At pH 7.0, PcS(2)Al incorporates into the vesicles with a high affinity constant (2.7x10(6) M(-1), in terms of phospholipid concentration). The fluorescence changes following rapid mixing of PcS(2)Al with vesicles are biphasic. The first phase is attributed to the entry of PcS(2)Al into the vesicles, as deduced from the linear dependence of the rate upon lipid concentration. More surprisingly, this rate is strongly pH dependent with a marked maximum around pH 7.3, a result interpreted in terms of the coordination state of the aluminum ion in aqueous solutions. At this pH, a hydroxide ion neutralizes the residual positive charge of the metal ion that remains unbalanced after coordination by the phthalocyanine cycle. A water molecule is likely to complete the metal coordination sphere. Only this form, PcAl(+)(OH(-))(OH(2)), with an uncharged core is quickly incorporated into the vesicles. The protonation of OH(-) or the deprotonation of the coordinated H(2)O leading to a positively or negatively charged core, respectively, account for the observed pH effect. Studies on the effect of cholesterol addition and exchange of PcS(2)Al between vesicles and albumin all indicate the absence of transfer of the phthalocyanine between the vesicle hemileaflets, a result expected from the presence of the two negatively charged sulfonated groups at the ring periphery. Instead, the slower kinetic phase is likely due to the movement of the phthalocyanine becoming more buried within the outer leaflet upon the loss of the water molecule coordinated to the aluminum ion.

Spectrofluorimetric study of porphyrin incorporation into membrane models--evidence for pH effects.

The effects of hydrophobicity and charges of dicarboxylic porphyrins upon their interactions with membrane model systems are investigated. Four protonation steps are evidenced from fluorescence emission studies of hematoporphyrin IX and its more hydrophobic parent compound lacking of alcoholic chain, deuteroporphyrin IX. They are attributed to the successive protonations of the inner nitrogens of the porphyrin cycle (pK = 4.7 and 2.9 for hematoporphyrin and 4.4 and 2.7 for deuteroporphyrin) and successive deprotonations of propionic groups (pK approximately equal to 5.0 and 5.5 for hematoporphyrin and 5.4 and 6.0 for deuteroporphyrin). These porphyrins, as well as their dimethyl ester forms, are shown to incorporate as monomers into the hydrophobic bilayer of egg phosphatidylcholine small unilamellar vesicles, although the esterified forms are highly aggregated in aqueous solutions. In the case of the non-esterified forms, the incorporation of the porphyrins into the lipidic bilayer is reversible and strongly pH-dependent. A theoretical model is presented which takes into account the various protonation steps and the partition equilibria of the porphyrin between the vesicle lipidic phase and the water medium. The neutral form of the porphyrin (i.e., carboxylic groups protonated) presents the higher affinity, with constants of K approximately equal to 2 X 10(5) and K approximately equal to 6 X 10(6) M-1 (relative to lipid concentration) for hematoporphyrin and deuteroporphyrin, respectively. Protonation of one inner nitrogen leading to the monocationic form is sufficient to prevent incorporation into the hydrophobic bilayer. On the other hand, deprotonation of the peripheral propionic chains leading to anionic forms is less effective. These interactions between vesicles and porphyrins lead to shifts of the apparent pK of nitrogens and carboxylic groups, the latter one being now in the range of physiological pH. These results are discussed with regards to the hypothesis of a possible role of pH in the preferential uptake of porphyrins by tumors.

Prevalence, risk factors and prognosis of hypernatraemia during hospitalisation in internal medicine.

INTRODUCTION: Hypernatraemia in hospitalised patients is less common and less studied than hyponatraemia, although it also seems to be associated with a poor prognosis. The present study evaluates its prevalence, risk factors and prognosis in an internal medicine department. METHODS: Full hospital stays over 28 months in a 36-bed internal medicine department were analysed retrospectively. Patients with at least one plasma sodium ≥ 150 mmol/l were compared first with all other patients and then individually with sex- and age-matched normonatraemic controls. RESULTS: Plasma sodium ≥ 150 mmol÷l was observed during 49÷1945 hospitalisations (2.6%); it was acquired during hospitalisation in 30 cases (61%). Hypernatraemic patients were significantly older with no gender difference. They were comparable with their matched normonatraemic controls regarding the Charlson comorbidity index, although individual comorbidities varied. They were bedridden in 45% vs 15% for controls (p = 0.001). Nearly one-third of hypernatraemic patients had an increased extracellular fluid volume. Hypernatraemia was associated with higher in-hospital mortality (43% vs 2%, p < 0.001) and longer hospitalisation (median 21 vs 10 days, p = 0.004). CONCLUSION: Hypernatraemia is more likely to occur in older and dependent patients and is associated with poor prognosis. Unlike classical teaching, it is often associated with increased extracellular fluid volume, even outside intensive care units.

Sequence of rat lipoprotein lipase-encoding cDNA.

A rat lipoprotein lipase (LPL)-encoding cDNA (LPL) has been entirely sequenced and compared to the sequences of all the LPL cDNAs reported in other species. As expected, high homology was found between the coding exons. The putative catalytic triad, Ser132, Asp156, His241, according to human numbering, is conserved in rat. As is the case in mouse, an Asn444 present in human LPL is also missing. The major divergences between human, mouse and rat LPLs were observed in the untranslated exon 10, where (i) the rat cDNA exhibits a 157-bp insertion and an 81-bp deletion relative to human; (ii) neither the B1 repeat nor the homopurine stretch reported in mouse can be recognized, and (iii) the rat cDNA displays several A+T-rich stretches.

Cloning, sequencing and structural analysis of 976 base pairs of the promoter sequence for the rat lipoprotein lipase gene. Comparison with the mouse and human sequences.

We cloned and sequenced the -976bp promoter of the rat lipoprotein lipase LPL gene. The sequence was compared with the mouse and human sequences. The homology between the rat and mouse LPL nucleotide sequences was not quite as strong in the promoter sequence as in the coding sequence. Among the 976nt promoter there were 118 divergences, i.e. 11.8%, compared to only 5.6% for the LPL coding region. However, within the 200nt immediately 5' to the transcriptional start site (proximal promoter), the divergence was only 4%. New potential cis-elements (such as CACCC, GATA, GC and GA boxes, IRS, Krox, MEF 2, E-box, CCArGG and 1/2 VDRE) were identified in the rat, mouse or human LPL gene.

Targeting of HIV gp120 by oligonucleotide-photosensitizer conjugates. Light-induced damages.

Some guanine-rich oligonucleotides inhibit HIV infectivity through interaction with the gp120 glycoprotein. Besides, photoinactivation of viruses attracts attention for blood decontamination. The feasibility of targeting a red light-absorbing chlorin-type photosensitizer to gp120 through covalent coupling with 8-mer phosphodiester oligodeoxynucleotides is investigated. Some conjugates inhibit binding of antibodies directed to gp120. Inhibition is significantly increased upon red light activation. The activity of the conjugates correlates with their ability to self-associate, a process strongly favored by the propensity of the hydrophobic chlorin moiety to dimerize. Thus, the photosensitizer moiety both promotes structures with a higher affinity for gp120 and, upon light activation, can induce site-directed damages to the protein.

Fundamental aspects in tumor photochemotherapy: interactions of porphyrins with membrane model systems and cells.

Some molecular aspects underlying photochemotherapy and photodiagnosis of tumors with porphyrins are reviewed. The nature of the clinically used photosensitizer HpD is first presented along with structures of molecules found to be efficient in vitro. The possible role of pH in the preferential retention of dicarboxylic porphyrins by tumors is discussed in light of results obtained with membrane models. The uptake of dicarboxylic porphyrins by cells most likely involves passive mechanisms. Cell photoinactivation using a purified porphyrin does not depend upon the incubation time but only on the intracellular concentration of the dye. This likely reflects a poor specificity of the photoinactivation processes with regard to the cellular localization of the dye. The properties which should be presented by more efficient photosensitizers are discussed.

Intravenous immunoglobulin therapy for prevention of infection in high-risk premature infants: report of a multicenter, double-blind study.

The effectiveness of intravenously administered immunoglobulin (Ig) therapy for prophylaxis of infection was evaluated in high-risk preterm infants. Two hundred thirty-five premature newborns were randomly assigned, in a double-blind controlled trial, to treatment and placebo groups. Thirty-five infants (29%) of the Ig group and 29 (25%) of the placebo group had one or more episodes of certain infection. Thirty infants (25%) of the Ig group and 18 (16%) of the placebo group had one or more episodes of probable infection. No significant differences were observed in the incidence of certain or probable infection in treated and control infants. Nevertheless, among the infants who had one or more certain or probable episodes of infection, more of them belonged to the Ig group than to the placebo group. The possible deleterious effect of the administration of large amounts of polyspecific Ig is discussed.

Model studies in cytochrome P-450-mediated toxicity of halogenated compounds: radical processes involving iron porphyrins.

Haloalkane toxicity originates from attack on biological targets by reactive intermediates derived from haloalkane metabolism by a hemoprotein, cytochrome P-450. Carbon-centered radicals and their peroxyl derivatives are most likely involved. The reactions of iron porphyrin--a model for cytochrome P-450--with various carbon-centered and peroxyl radicals generated by pulse radiolysis are examined. Competition between iron porphyrin and unsaturated fatty acids for attack by peroxyl radicals is pointed out. These kinetic data are used to derive a model for toxicity of haloalkanes with particular attention to carbon tetrachloride and halothane. The importance of local oxygen concentration and structural arrangement of fatty acids around cytochrome P-450 is emphasized.

Kinetics of induction of DNA damage and lacZ gene mutations in stomach mucosa of mice treated with beta-propiolactone and N-methyl-N'-nitro-N-nitrosoguanidine, using single-cell gel electrophoresis and MutaMouse models.

beta-Propiolactone (BPL) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) are two direct alkylating agents that induce multiple genetic lesions and tumors in the rodent stomach. We measured the kinetics of the induction of DNA damage by using the single-cell gel electrophoresis assay (SCGE) and the induction of gene mutations by using the MutaMouse model in the glandular stomach mucosa of mice exposed to a single oral administration of BPL or MNNG. The aims were to determine the optimal sampling time and to investigate the cause-effect relationship between DNA damage and gene mutations. The induction of comets, evaluated in individual cells with the tail moment, was analyzed 1, 2, 4, 24, and 72 hr after a single oral administration of 25 mg/kg BPL or 20 mg/kg MNNG. The effects of both compounds were most intense at the earlier sampling times (1-2 hr), tailing off 4 hr after treatment and becoming undetectable at 72 hr. The lacZ mutant frequency (MF) was measured 3, 7, 14, 28, and 50 days after a single oral administration of 150 mg/kg BPL or 100 mg/kg MNNG, and 3 and 14 days after a single administration of 25 mg/kg BPL or 20 mg/kg MNNG. The MF was strongly enhanced at the highest doses and all sampling times, the most marked effects being observed 14 days (11.1-fold) and 28 days (19.0-fold) after BPL and MNNG administration, respectively. At the lowest doses, only a small increase in MF ( approximately 2.5- to 3.5-fold) was found at both sampling times. Primary DNA damage detected with SCGE shortly after treatment (1-2 hr) was rapidly (3 days) transformed into stable gene mutations that remained detectable for 50 days. These results illustrate the ability and complementarity of the SCGE and MutaMouse models to assess the genotoxicity of direct alkylating agents in the mouse gastric mucosa in vivo.

Uptake and retention of Photofrin by cultivated human lymphoblastic cells (Reh6): preferential affinity of the cells for a minor component demonstrated by normal phase chromatography.

The uptake of Photofrin by the human cultivated lymphoblastic cell line Reh6 was studied using normal phase high performance liquid chromatography (HPLC) techniques. Relative cellular uptake of eight fractions (uptake/amount of component initially present in the incubation solution) was determined. After 4 h of incubation, protoporphyrin and a small fraction (denoted 4) were incorporated to a greater relative extent than the other fractions. Weakly incorporated components (hematoporphyrin and aggregate-like components) were better retained by cells than the hydrophobic monomeric porphyrins (protoporphyrin and hydroxyethylvinyldeuteroporphyrin). Thus, any benefit gained from a higher uptake was mostly cancelled by a fast release--a situation observed for all fractions except for fraction 4, which displayed both high uptake and good cellular retention. This pattern was not modified when Photofrin concentration or serum percentage was changed. Fraction 4 was further resolved using a gradient system on normal silica. A single component appeared to be mostly responsible for the favorable properties presented by fraction 4, i.e. high uptake and retention within cells. This component was found to correspond to a late eluted peak in the typical reverse-phase HPLC profile of Photofrin. These results emphasize the possible role of minor Photofrin components.