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The prevalence of smoking has increased among young people aged 14 to 18 between 1993 and 1999, and most notably among girls within the same period. These observations illustrate the necessity for significant changes in mass media campaigns and education programmes related to the prevention of smoking among youth. The objective of this survey, initiated by the city of Besançon and the French National Mutual Insurance of Doubs, was to describe and analyse the knowledge and rationale of high school students on tobacco and their opinions in terms of prevention. Twelve public and private high schools in Besançon and Morteau (Doubs-France) participated in the survey; the group also represented a mix of general and professional schools. The questionnaire was filled out by 970 students selected at random. 96% of the students indicated cancer as being the main illness linked to tobacco and 94% stated that second-hand smoke constitutes a health risk. 61% admitted to seeking out the psychoactive effects of smoking. The students responses confirm that the types of messages relayed in a smoking prevention campaign which have an impact on them are: evoking fear of death (74%) and the use of humor (16%). One-third of high school students find that it is unacceptable to forbid smoking on school premises. The knowledge of the dangers related to smoking is not sufficient to keep young people from smoking and confirms that an educational approach based solely on knowledge and facts will not be sufficient to decrease their tobacco consumption. It is important to take into account the image that young people have of tobacco as a means to combat stress in future prevention strategies and campaigns.

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In this review we recall the main physical properties of nitric oxide. The irreversible reactions of NO with O2 and O2.-, which yield strongly oxydant and nitrosating, and therefore toxic, species, are described in kinetic terms. Nearly all metalloproteins are potential targets for NO, often detectable by EPR spectroscopy. The case of hemoglobin in vitro and within circulating erythrocytes, especially in pathophysiological cases, is particularly described. A few examples of hemoproteins activated or inhibited by NO are given. Results obtained with cellular systems responding to cytokines are summarized, together with the effects of NO synthesis on [FeS] clusters-containing proteins, on ribonucleotide reductase and on the proteins implicated in iron metabolism.

Nitric oxide is synthesized in mammalian cells from L-arginine or from pharmaceutical drugs. It forms paramagnetic complexes with some metalloproteins, including hemoglobin. Induction of NOSi following LPS or cytokine activation of murine macrophages has various effects, such as inhibition of mitochondrial respiration and that of DNA biosynthesis through interaction of NO with specific metalloenzymes. Induction of NOSi in a generator cell such as macrophage gives the same metabolic effects in target cells. NO is also detected in pathological states such as septic shock, diabetes mellitus and allograft, where the inducible L-arginine-NO pathway plays an important role. Electron Paramagnetic Resonance spectroscopy enables to detect unambiguously such specific molecular targets for NO in mammalian whole cells and organelles.

Self-selection of dietary lysine was studied in one 42-d experiment involving 100 Large White growing pigs, with an equal number of females and castrated males, initially weighing 17.7 kg, within 5 treatments of 20 animals in each. A common basal diet (17% CP, 13.8 MJ DE/kg) based on maize, soybean meal and peanut meal, and containing a deficient level of lysine (0.61%), was used. Supplementary L-lysine was provided to obtain suboptimal (0.74%), optimal (0.85%) and superoptimal (1.21%) levels of total lysine for growth, as assumed from usual recommendations. In addition to treatment 1, a control where pigs were fed ad libitum a single diet with 0.85% lysine, 4 treatments with free choice of lysine within paired diets were compared. These included deficient or suboptimal levels of lysine on the one hand and optimal or superoptimal levels on the other according to a 2 x 2 factorial plan: 0.61 vs 0.85% (treatment 2), 0.74 vs 0.85% (treatment 3), 0.61 vs 1.21% (treatment 4), 0.74 vs 1.21% (treatment 5). The results showed sex difference in diet selection according to lysine content. Females had a distinct preference for the superoptimal level (1.21%) compared to the optimal level (0.85%), especially during the initial period of the trial, their requirement being higher than the presupposed 0.85% optimal level. For castrated males, the preference for lysine was restricted to the lower 0.85% level. The ability of females to self-select a greater proportion of the high lysine feed as opposed to castrated males was related to a higher potential for lean tissue growth. These results confirm that the growing pig is able to differentiate between diets differing only in their lysine contents. Complementary observations on plasma-free amino acids suggested the use of diets adequately balanced for amino acids when offered for free choice.

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The first part of this paper deals with the distribution of the protein fraction (total protein, amino acids) in the tissues and body compartments in the growing pig, according to age, growth potential (sex, genotype) and nutritional factors (feeding level). Overall protein retention is studied in the second part of the paper. The following points have been considered: changes in the protein retention curve during growth; variations according to the type of pig and nutrient supply; particular aspects of amino acid deposition with a relative constancy in the amino acid composition of deposited protein during the major part of growth. In the third part, the following consequences of variations in protein retention on protein requirement for growth have been analyzed: --relatively constant ratios between the requirements for individual essential amino acids and non-essential nitrogen (using lysine as a reference); --relation between protein (amino acid) requirement and level of protein deposition; --variations in the efficiency of utilization of dietary amino acids for growth, according to muscle growth potential and production objectives (final slaughter weight, type of pig and feeding program). The benefit of taking into consideration the components of apparent protein retention (synthesis and degradation) is discussed with a view to better adapting protein feeding to growth potential.

Reduction of nitrite by NADH catalyzed by Pseudomonas aeruginosa nitrite reductase is inhibited by a high concentration of nitric oxide NO. Contrary to what is currently admitted, we find that the nitrite reduction proceeds to the nitrogen monoxide N2O stage. EPR spectra show that, during the catalytic cycle, the enzyme forms specific Fe2+-NO heminic complexes.

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In a series of 250 cases of cerebral vascular accident, the authors have selected 12 patients whose embolus appeared to have originated in the heart, although this could not be confirmed by clinical examination, ECG, Holter system monitoring and echocardiographic studies. Angiocardiography, complemented or not by His bundle exploration and/or coronary arteriography, revealed the presence of a heart disease likely to produce emboli in 11 cases, and in 8 cases, this was prolapsed mitral valve. These 11 cases represent 4.5% of the whole series and 22% of cases with emboli of suspected cardiac origin. Thorough cardiological studies, therefore, seem to be justified in young adults presenting with stroke. The high incidence of prolapsed mitral valve is in keeping with recently published data.

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Les spectres de resonance paramagnetique electronique des nitrosyl-hemoproteines apportent des renseignements directs sur le complexe heminique ; l'oxyde azotique, ligand du fer de l'heme, apparait comme un marqueur extremement sensible aux changements de conformation proteique. De plus l'analogie entre l'oxyde azotique et l'oxygene permet l'etude des mecanismes de reactions de tres nombreuses hemoproteines ; en particulier, l'application a l'etude des interactions dans l'hemoglobine a permis de caracteriser le degre d'inequivalence structurale et fonctionnelle des sous-unites proteiques et de suggerer fortement l'existence d'intermediaires conformationnels dans les reactions de l'hemoglobine.

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