Photophysical comparative study of amylose and polyvinyle pyrrolidone/single walled carbon nanotubes complex.

Progressive addition of hydroxypropylated amylose (AmH), from 0.05 wt% to 4.5 wt%, to single-walled carbon nanotubes (SWNTs) in aqueous surfactant suspensions quenches the intrinsic near Infra-Red fluorescence of semiconducting SWNTs while dispersions obtained with a same amount of polyvinylpyrrolidone (PVP) remain luminescent. Near Infra-Red emission spectroscopy (fluorescence and Raman scattering) of the samples is used to characterize the supramolecular organization of these polymer/SWNT complexes. The SWNTs are found to be wrapped by the PVP chains and not by the AmH chains which rather form AmH/surfactant/SWNTs complexes. In PVP/SWNTs dispersion, the fluorescence line position and intensity are affected by dielectric screening. In the case of AmH/surfactant/SWNTs complex, dielectric screening plays also a role but quenching occurs above about 3 wt% of AmH. We attribute the quenching to the formation of a "composite like" microstructure by opposition to stabilized dispersion.

Cancelling discrete and stopping ongoing rhythmic movements: Do they involve the same process of motor inhibition?

Motor inhibition is considered to be an important process of executive control and to be implicated in numerous activities in order to cancel prepared actions and, supposedly, to suppress ongoing ones. Usually, it is evaluated using a "stop-signal task" in which participants have to inhibit prepared discrete movements. However, it is unknown whether other movement types involve the same inhibition process. We therefore investigated whether the inhibition process for discrete movements is involved in stopping ongoing rhythmic movements as well. Twenty healthy adults performed two counterbalanced tasks. The first task was used to estimate the stop-signal reaction time (SSRTd) needed to inhibit prepared discrete key-pressing movements. In the second task, participants drew graphic patterns on a tablet and had to stop the movement when a stop-signal occurred. We calculated the rhythmic stop signal-reaction time as the time needed to initiate stopping such ongoing rhythmic movement (SSRTr) and the same latency relative to the period of the rhythmic movement (relSSRTr). We measured these delays under different movement frequencies and motor coordination conditions and further investigated whether they varied as a function of several parameters of the rhythmic movements (speed, mean and variance of the relative phase, and movement phase at several time events). We found no correlation between inhibition measures in the two tasks. In contrast, generalized linear models showed a moderate yet significant influence of the motion parameters on the inhibition of ongoing rhythmic movements. We therefore conclude that the motor inhibition processes involved in cancelling prepared discrete movements and stopping ongoing rhythmic movements are dissimilar.

An Application May Help Improve Protein Consumption after Bariatric Surgery.

This brief communication suggests that in patients who had bariatric surgery and in whom protein intake is lower than 60 g/d, the use of an application is likely to improve protein intake.

Relationship between the chemical structure and the mutagenic and carcinogenic potentials of five naphthofurans.

We have analyzed the relationship between the biological activities and chemical structure of five naphthofurans. The compounds studied included 2-nitro-7-methoxynaphtho[2,1-b]-furan (R 7000) (Compound A), 2-nitro-8-methoxynaphtho[2,1-b]-furan (Compound B), 2-nitronaphtho[2,1-b]furan (Compound C), 2-nitro-7-bromonaphtho[2,1-b]furan (Compound D), and 7-methoxynaphtho[2,1-b]furan (Compound E), the nonnitrated analogue of Compound A. The genotoxic activities of the compounds were studied in V79 cells using the micronucleus, sister chromatid exchange, and hypoxanthine-guanine phosphoribosyltransferase locus mutation tests. This allowed us to classify their mutagenic properties in the following order: A congruent to B much greater than C greater than D greater than E. However, in the in vivo short-term skin tests, the order in activities of the first three compounds is reversed, and the five compounds can be classified in decreasing rank of potency: C greater than B greater than A greater than or equal to E congruent to D. The two compounds tested for in vitro transformation, Compounds A and B, demonstrated a positive effect in both the C3H10T1/2 and the Syrian hamster embryo cell systems. The biological activities of Compounds A, B, C, and D appeared to be strongly linked to the presence of a NO2 group in position 2. These activities were enhanced or decreased by a methoxy group in position 7 or 8. Almost all activities were suppressed if the methoxy group in position 7 was replaced by a bromine (Compound D). The positive results obtained in the cell transformation assays and in the short-term skin tests indicate that Compounds A, B, and C are probably carcinogenic. Therefore, further in vivo studies should be accomplished before using the 2-nitronaphthofuran derivatives in human and animal treatments.

Telematic expert system Diabeto. New tool for diet self-monitoring for diabetic patients.

OBJECTIVE: To evaluate Diabeto, a computer-assisted diet education system. RESEARCH DESIGN AND METHODS: One hundred five patients with insulin-dependent diabetes mellitus (IDDM) or non-insulin-dependent diabetes mellitus (NIDDM) were divided into two randomized groups to participate in the evaluation of Diabeto. With free access through Minitel, the French public videotex network, Diabeto helps diabetic patients self-monitor their diets and balance their meals with personalized counseling. RESULTS: During the first 6-mo study, group A (54 patients) used Diabeto, whereas group B (51 patients) were control subjects. For the second 6-mo study, group B used the system. Evaluation was based on patients' dietetic knowledge, dietary habits, and metabolic balance. CONCLUSIONS: Diabeto led to a significant improvement of dietetic, knowledge in group A (P less than 0.0005) and also to improved dietary habits; decreased caloric intake in patients initially overeating (P less than 0.05), increase of dietary carbohydrate from 39.7 +/- 0.7 to 42.9 +/- 0.9% in patients with an initial intake less than 45% carbohydrate, and decrease of fat intake from 41.9 +/- 0.9 to 37.4 +/- 1.1% in patients with an initial intake of greater than 35% fat (P less than 0.0005). In the second study, in addition to similar improvements to those observed in the first study, HbA1 decreased from 11.0 +/- 0.4 to 9.9 +/- 0.4% (P less than 0.005) and fructosamine from 5.00 +/- 0.17 to 4.57 +/- 0.17% (P less than 0.001). Diabeto appears to be an effective therapeutic tool in the control of metabolic diseases.

[A new therapy with bortezomib, an oncologic medicinal product of the year 2004]. / Une nouvelle thérapie ciblée avec le bortézomib, médicament oncologique de l'année 2004.

Proteasome-mediated proteolysis is a mechanism for mediating important regulatory proteins within the cell. Proteins that have been targeted for degradation by the proteasome are convalently tagged with a poly-ubiquitin protein chain prior to be recognized by the 19S subunit of proteasome. This degradation system controls the expression of a wide variety of cellular targets including tumor suppressors such as p53, inhibitor of nuclear factor NFkappaB, cyclin-dependent kinase inhibitors such as p21 and p27. Because of these functions, the proteasome has become a new target for cancer treatment. The potent and selective proteasome inhibitor, PS-341 or Velcade was approved in the United States and launched in may 2003 for the treatment of multiple myeloma patients who have received at least two prior therapies. On April 2004, the European commission granted marketing authorization for Velcade with the same indication. The same year 2004, the Nobel Prize in chemistry was awarded to three researchers "for the discovery of ubitiquin-mediated protein degradation", a regulated process by which proteins are cleaved into peptides inside cells.

Comparison of the carcinogenic effects of two 2-nitro-naphthofurans injected sub-cutaneously in rats.

7-Methoxy-2-nitro-naphtho[2,1-b]furan (R 7000) and its methylated homolog in position 1 (R 7372) are among the most mutagenic agents presently known, as shown by the results obtained both in the Ames test and in the SOS Chromotest. Their carcinogenic effects were tested in rats. We were able to confirm the carcinogenic effects of these nitro-naphthofurans, the presence of a methyl group--while increasing the mutagenic effect of R 7000 10 times--induces a significant decrease of the carcinogenic effects in R 7372. The discrepancy between the mutagenic effects in bacterial assays and the carcinogenic effects of these two 2-nitro-naphthofurans remains to be explained.

Evaluation of microcomputer nutritional teaching games in 1,876 children at school.

OBJECTIVE: We evaluated in a prospective study microcomputer nutritional teaching games and their contribution to the children's acquisition of nutritional knowledge and improvement of eating habits. MATERIAL AND METHODS: One thousand eight hundred seventy-six children aged 7-12 years took part in this study at school. All 16 schools of the same school district were randomized into two groups: games group and control group, both receiving conventional nutritional teaching by their teachers. The children in the games group played computer games during the conventional nutritional teaching period (2 hours a week for 5 weeks). At completion of the study, dietetic knowledge and dietary records were evaluated in both groups. RESULTS: Dietary knowledge tests results were better in the games group (p<0.001). The children in the games group had a significantly better balanced diet for an energy intake of about 1900 kilocalories: more carbohydrate (46.4 +/- 0.2% vs 45.7 +/- 0.2%, p<0.05), less fat (37.1 +/- 0.1% vs 37.6 +/- 0.2%, p<0.05), less protein (16.5 +/- 0.1% vs 16.7 +/- 0.1%, p<0.05), less saccharose (11.5 +/- 0.1% vs 12.2 +/- 0.2%, p<0.001), more calcium (p<0.001) and more fiber (p<0.05). The games group had a better snack at 10 a.m., a less copious lunch and less nibbling (p<0.001). CONCLUSION: The children in the games group had slightly but significantly better nutritional knowledge and dietary intake compared to children in the control group. Using our micro computer nutritional teaching games at school provides an additional and modern support to conventional teaching.

Multicenter randomized evaluation of a nutritional education software in obese patients.

OBJECTIVE: To study the efficacy of the nutritional education software, Nutri-Expert, in the management of obese adult patients. MATERIAL AND METHODS: Two groups of obese patients were followed up over one year in a randomized study: the first group received close traditional management (seven nutritional visits over the year, with physicians and dietitians conjointly) and the second one also used at home by Minitel the Nutri-Expert system. 557 patients were enrolled in the study by 16 French centers of diabetology and nutrition. Body mass index (BMI), tests of dietetic knowledge, dietary records and centralized biological measurements were assessed at inclusion, 6 and 12 months. 341 patients were evaluable at the end of the year. RESULTS: The group using Nutri-Expert scored significantly better in the tests of dietetic knowledge than the control group. For all patients, nutritional education led to a significant improvement in BMI, dietary records and biological measurements, without significant difference between the two groups. Five years after the end of the study, the weight of 148 patients was recorded; mean BMI was significantly lower than the initial value but there was no significant difference between the two groups. CONCLUSION: In the management of obese patients, Nutri-Expert system has a role to play in reinforcing nutritional knowledge; if regular follow-up is not possible, or if a large series of obese patients is to be treated, Nutri-Expert could partly replace traditional management, for example between visits.

Inhibition of DNA synthesis in relation to enhanced survival of UV-damaged herpes virus in monkey cells treated by a variety of 2-nitronaphthofurans.

Various 2-nitronaphthofuran derivatives (related to each other by simple structural modifications) were tested for 2 different effects in CV-1 monkey kidney cell cultures: the immediate inhibition of normal DNA synthesis and the capacity of pretreated cultures (40 h of contact) to support the replication of UV-damaged Herpes simplex virus (HSV). For all compounds tested, a fair correlation was found between their efficiencies to inhibit cellular DNA synthesis and to provoke an increase in UV-HSV production (virus reactivation). Virus reactivation was due to an increase in both the number of virus-producing cells and the amount of infectious particles produced per cell. The most efficient 2-nitronaphthofurans (particularly 2-nitro-7-methoxy-naphtho[2,1-b]furan-R 7000) were at least as potent as aflatoxin B1 in inducing virus reactivation.

Naphthofurans induced chromosomal aberrations detected in metaphase, anaphase and telophase V79 Chinese hamster cells.

The mutagenic activities of 5 newly synthesized naphthofurans were analysed in two in vitro cytogenetic assays: the metaphase chromosomal aberration assay and the anaphase telophase bridge-fragment assay. Both assays were conducted using V79 Chinese hamster cells. The compounds included: 2-nitro-7-methoxynaphtho[2,1-b]furan (A), 2-nitro-8-methoxynaphtho[2,1-b]furan (B), 2-nitro-naphtho[2,1-b]furan (C), 2-nitro-7-bromonaphtho[2,1-b]furan (D) and 7-methoxynaphtho[2,1-b]furan (E). The cells were treated with 3 concentrations (0.1, 0.2 and 0.4 microgram/ml) of each compound, in the dose range already tested in studies on the mutagenic properties of the same compounds realised with other systems. The highest concentration, only, was used in the anaphase-telophase assay. In the first approach, compounds A, B and C were active while compounds D and E did not increase significantly the aberration frequency above that of the DMSO controls. The results were confirmed in the second approach. They demonstrated that the two studies were complementary. Based on their genotoxic activities, the 5 compounds were ranked in the following decreasing order of potency: A congruent to B much greater than C greater than D congruent to E congruent to DMSO; which is comparable to the ranking order obtained in different in vitro mutagenic and carcinogenic assays. All these activities are closely related to the highly specific molecular structure of each compound, particularly to the nature and position of the different substituents introduced on the skeleton.

Mutagenic activity of benzofurans and naphthofurans in the Salmonella/microsome assay: 2-nitro-7-methoxy-naphtho[2,1-b]furan (R7000), a new highly potent mutagenic agent.

A series of benzofurans and naphthofurans was examined through the Salmonella/microsome assay. (i) With one possible exception, only 2-nitro derivatives give a mutagenic response. However, it appears that the mutagenic potency depends notably on the nature and the position of the other substituents in the molecule. (ii) The mutagenic response occurs in strains TA1537, TA1538, TA98 and TA100 but not in strain TA1535. Reversion of the missense mutation of TA1535 is thus induced only in presence of the plasmid pKM101. (iii) This mutagenic response is at least partially dependent on the bacterial nitroreductase activities and is usually lower in presence of activating mixture from rat liver. (iv) One of the compounds tested, 2-nitro-7-methoxynaphtho[2,1-b]furan (R7000), may be the most potent mutagen examined so far in the Salmonella/microsome assay. It yields about 200 000 revertants/nanomole on strain TA100 in the standard plate test. The relation between structure, mutagenic potency and other biological activities of the compounds are briefly discussed.

Genetic toxicology studies with 2-nitrobenzofurans and 2-nitronaphthofurans.

The genetic toxicity of benzofurans and naphthofurans was further examined. (i) Seven new 2-nitronaphthofurans tested give a positive response on strains TA1537, TA1538, TA98, TA100, but not on strain TA1535. This response depends at least partially on the bacterial nitroreductase activities and is decreased in presence of activating mixture from rat liver. (ii) A correlation is observed between the mutagenic potency assayed in the Mutatest and the phage-inducing potency assayed in the Inductest. The relevance of these results and of complementary tests on uvr + Salmonella strains and the Spermatest are briefly discussed in perspective of the possible genetic toxicity of the compounds on mammals.

Photobiological activities of 1,6-dioxapyrene in pro- and eukaryotic cells.

The photobiological effect of a new pyrene derivative, 1,6-dioxapyrene (1,6-DP), was studied in Salmonella typhimurium (strain TA100) and in the diploid strain D7 of the yeast Saccharomyces cerevisiae. In Salmonella, 1,6-DP shows little mutagenicity in the dark in comparison to benzo[a]pyrene (B[a]P). This mutagenic activity decreases in the presence of liver S9 homogenates from Aroclor induced XVIInc/Z mice. However, in combination with 365 nm (UVA) radiation and in the absence of S9 mix, 1,6-DP behaves as an effective photodynamic compound inducing lethal and mutagenic effects in both organisms. In yeast, its activity, like that of B[a]P, is highly dependent on the presence of oxygen. For the same incident dose of UVA, 1,6-DP is, however, at least 6 times more effective than B[a]P in inducing cytotoxic and mutagenic effects. At equitoxic doses, 1,6-DP is as photomutagenic as B[a]P, suggesting that in both cases mutagenicity is due to similar mechanisms. Spectrophotometric measurements indicate physical interaction of 1,6-DP with DNA in the dark. Laser flash photolysis experiments show that 1,6-DP generates singlet oxygen with a quantum yield of 0.17. In vitro 1,6-DP produces oxidative damage to guanine bases specific for singlet oxygen mediated reactions. Alkaline step elution analysis of 1,6-DP plus UVA treated yeast cells indicates a decrease in average molecular weights in DNA and an induction of single strand breaks (ssb) originating from alkali labile sites. This effect is enhanced by D2O and is thus likely to be due to the production of singlet oxygen. The strand breaks appear to differ from those induced by gamma-rays because little, if any, repair of these ssb occurs during 30 min of post-treatment incubation in complete growth medium. These results suggest that the photobiological effects of 1,6-DP are due to oxidative damage in DNA mostly induced by singlet oxygen.

An alternative method for the measurement of mineral sulphide in wastewater.

A simple and rapid procedure for sulphide measurement in crude oil refinery wastewater has been developed. This method is based on the knowledge of the UV response of sulphur compounds and the mathematical deconvolution of the sample spectrum using reference spectra (specific compounds or aggregate spectra). The detection limit of the method is 0.5 mg l(-1) for a quartz cell pathlength of 10 mm. The range is up to 15 mg l(-1). The method has been validated for crude oil refinery wastewater. Compared to conventional methods, the UV determination is quicker and easier to run.

Mode of action of nitro-heterocyclic compounds on Escherichia coli.

The inhibitory and bactericidal activities of several different nitro-heterocyclic compounds, such as nitrofuran, nitronaphthofuran, nitrobenzofuran, nitroimidazole and nitrothiazole, were assessed in vitro. All these substances except nitroimidazole were active against Escherichia coli, though to different degrees. Under anaerobic test conditions the antibacterial activity increased slightly. Nitroreductase-deficient mutants, however, were highly resistant to all nitro-compounds, indicating that only when the nitro-group is reduced to these agents get into an active antibacterial form. SOS repair-deficient strains were much more susceptible to the nitro-containing substances than repair-proficient counterparts, indicating that damage to bacterial DNA is the essential mechanism of antibacterial activity of all nitro-heterocyclic compounds.

[Cytostatic action of 2-nitronaph-thofurans on L1210 murine leukemia cells in semi-solid médium (author's transl)]. / Action cytostatique de nitro-2 naphtofurannes sur des cellules de la leucémie murine L1210, en milieu semi-solide.

The cytostatic effect of various derivatives of 2-nitro-naphthofurans has been determined in vitro on L1210 leukemia cells. A recently described new bio-assay (Discotest) was used, which consists in plating the cells in soft agarose and placing on top of the agarose layer a paper disc soaked with the compound to be tested. The halo of inhibition of colony formation which results from diffusion of the compound is proportional to the logarithm of the compound concentration. The most active derivatives were the 2-nitro-7-methoxy and 2-nitro-8-methoxy-naphtho[2,1-b] furans which are known to be highly bactericidal and protozoocidal.

[Screening for lead poisoning in children by measuring lead levels in housing: a study of the Paris region]. / Dépistage du saturnisme infantile à partir de la recherche de plomb dans l'habitat: une étude en région parisienne.

Screening programs for lead poisoning in France rely usually on the preliminary identification of risk factors among children seen in Maternal and Child Health (MCH) clinics. To assess the potential relevance of screening strategies based on the quantification of exposure to lead in housing, we estimated first the prevalence of exposure to lead in a representative sample of older buildings, then the prevalence of lead poisoning among children living in those buildings where high levels of lead had been found. Exposure to lead was measured in dust and paint samples collected in hallways and other collective areas of the buildings. Venous blood samples were collected from the children aged 10 months to 6 years residing in buildings where lead exceeded 1.5 g/kg in paint samples or 1000 micrograms/m2 in dust samples. Paint and dust samples were collected in 137 buildings: 74% presented high dust and/or paint lead contents. Blood samples were collected from 145 out of a total of 189 children residing in these buildings: blood lead levels (PbB) were higher than or equal to 10 micrograms/dl for 65% of these children; 29% were higher than or equal to 15 micrograms/dl, 16% higher than or equal to 20 micrograms/dl. Out of 42 children with PbB > or = 15 micrograms/dl, 21 had not been previously identified through the screening program conducted in local MCH clinics. Clinic-based and environment-based screening appeared to be complementary. It seems thus justified to develop screening strategies based on the assessment of exposure to lead in the environment.

[Development of a self-administered questionnaire to assess women's satisfaction with maternity care]. / Développement d'un auto-questionnaire évaluant la satisfaction des femmes à l'égard des maternités.

OBJECTIVES: We describe the development and the validation of a French self-administered questionnaire which measures women satisfaction concerning care given during pregnancy. The analysis includes pregnancy monitoring, hospitalization for delivery and homecoming. METHODS: We considered the content validity, internal-consistency and the reproducibility by test-retest estimates. This survey also compared the characteristics of respondents and non-respondents. RESULTS: Response rate was 61% and the rate of reply per question was greater than 90%. Eleven dimensions are identified by principal-components analysis. Ten of them had good Cronbach's alpha coefficients (0.58 to 0.83). The convergence between open comments and questions and between the different methods to measure satisfaction was good. The test-retest estimates for each dimension were correct. CONCLUSION: This questionnaire is reliable. It is a valid tool for evaluation of satisfaction after pregnancy. Designed to be sent to the woman's residence 2 months after childbirth, it can be easily used in common practice.

[Health and violence as perceived by young people, a study of the Parisian region]. / Santé et violences perçues par les jeunes, une étude en région parisienne.

We know better the violences made by the youngs than those they suffer from. The purpose of this study is to assess, as for a city surrounding Paris, the prevalence of the violences they felt and its relation with the psychic uneasiness. Some 344 youngs (from 15 to 25 years old) selected in the city, have filled in an autoquestionnaire. It has shown that 61.6% of them have already suffered from violences, among them 44.5% from adults and what is more from institutional adults. 13.7% of the selected youngs were victims of regular violences in school sphere and 12.8% in urban environment. The expression of a psychic uneasiness is linked to the previous violences they have felt. The feeling of call for help by a psychologist or a psychiatrist is in relation with the past psychic discomfort and not with the past suffered violences.