Eating disorders throughout female adolescence.

Eating disorders (EDs) are conditions which are becoming more and more widespread among adolescents and they often lead them to seek the opinion of a professional health caregiver, including gynecologists and pediatricians. EDs, and particularly anorexia nervosa (AN), are usually classified as psychological or psychiatric disorders, but they may have major somatic implications and complications as osteoporosis, nutritional deficiencies, cerebral atrophy, cardiac and metabolic disorders. A key issue in the management is prevention or reduction of both the serious somatic consequences and the important mental health consequences (e.g. depression, psychosocial withdrawal, phobia and suicide), integrating different perspectives (psychological or psychiatric - individual and familial -, genetic, nutritional, pediatric, gynecological). Adolescence is a critical period for the onset of EDs though they may also involve younger children. In this case, the consequences on the development (height, weight, puberty) can also be significant. In this review, we will focus on eating disorders in adolescent girls with an emphasis on AN. We describe variations in ED characteristics and their management depending on age at occurrence. A possible ED should be considered by pediatricians consulted about delayed female growth and puberty as well as gynecologists in patients with primary or secondary amenorrhea or infertility.

[Inertia or overtreatment in children. When sleeping time is disturbed in infants: how to improve the family's distress]. / Inertie ou excès thérapeutique chez l'enfant: lorsque le sommeil de l'enfant n'est pas de tout repos pour lui, ses parents et le médecin.

Sleeping disorders are frequently encountered in infants and adolescents. They often induce a distress in the family, an individual sadness possibly leaving at time to maltreatment. In the normal infant or the medically fragile infant due to prematurity or an acute episode, complaints from the patient or family sources force the medical team to find an explanation or a treatment, which are not always adequate. In other conditions such as asthma, obesity, anorexia nervosa, autism, cerebral palsy, hyperactivity, the sleeping disorders may be so unnoticed or remain insufficiently investigated. Globally, in this domain, the clinical description is often imprecise and sleep studies underused. A more accurate assessment should lead to a better educative approach and more appropriate therapy.

Microorganisms in dry polar snow are involved in the exchanges of reactive nitrogen species with the atmosphere.

The snowpack is a complex photochemical reactor that emits a wide variety of reactive molecules to the atmosphere. In particular, the photolysis of nitrate ions, NO(3)(-), produces NO, NO(2), and HONO, which affects the oxidative capacity of the atmosphere. We report measurements in the European High Arctic where we observed for the first time emissions of NO, NO(2), and HONO by the seasonal snowpack in winter, in the complete or near-complete absence of sunlight and in the absence of melting. We also detected unusually high concentrations of nitrite ions, NO(2)(-), in the snow. These results suggest that microbial activity in the snowpack is responsible for the observed emissions. Isotopic analysis of NO(2)(-) and NO(3)(-) in the snow confirm that these ions, at least in part, do not have an atmospheric origin and are most likely produced by the microbial oxidation of NH(4)(+) coming from clay minerals into NO(2)(-) and NO(3)(-). These metabolic pathways also produce NO. Subsequent dark abiotic reactions lead to NO(2) and HONO production. The snow cover is therefore not only an active photochemical reactor but also a biogeochemical reactor active in the cycling of nitrogen and it can affect atmospheric composition all year round.

Evolution of the snow area index of the subarctic snowpack in central Alaska over a whole season. consequences for the air to snow transfer of pollutants.

The detailed physical characteristics of the subarctic snowpack must be known to quantify the exchange of adsorbed pollutants between the atmosphere and the snow cover. For the first time, the combined evolutions of specific surface area (SSA), snow stratigraphy, temperature, and density were monitored throughout winter in central Alaska. We define the snow area index (SAI) as the vertically integrated surface area of snow crystals, and this variable is used to quantify pollutants' adsorption. Intense metamorphism generated by strong temperature gradients formed a thick depth hoar layer with low SSA (90 cm(2) g-1) and density (200 kg m(-3)), resulting in a low SAI. After snowpack buildup in autumn, the winter SAI remained around 1000 m(2)/m(2) of ground, much lower than the SAI of the Arctic snowpack, 2500 m(2) m-(2). With the example of PCBs 28 and 180, we calculate that the subarctic snowpack is a smaller reservoir of adsorbed pollutants than the Arctic snowpack and less efficiently transfers adsorbed pollutants from the atmosphere to ecosystems. The difference is greater for the more volatile PCB 28. With climate change, snowpack structure will be modified, and the snowpack's ability to transfer adsorbed pollutants from the atmosphere to ecosystems may be reduced, especially for the more volatile pollutants.

[Diagnosis and treatment of pancreatic injuries in children]. / Mise au point et traitement des traumatismes pancréatiques chez l'enfant.

Pancreatic injury after trauma can occur in the child as an isolated lesion after a minor injury. The consequences can be severe in the absence of prompt diagnosis and treatment. Determination of mechanism of injury, clinical examination, blood amylase levels and abdominal CT-scan are first line steps for the evaluation of the injury. ERCP and MRI can be useful tools to further document injury to the pancreatic duct. In the absence of duct injury, conservative treatment can be applied. For the other cases, the treatment is surgical although newer techniques may be applied in selected cases.

Evaluation of depth profiling using laser resonant desorption as a method to measure diffusion coefficients in ice.

Diffusion of gases in ice is involved in cloud, snow, and ice core chemistry, but few data exist on the relevant diffusion coefficients. A novel method to measure diffusion coefficients in ice has recently been proposed by Livingston et al. (Anal. Chem., 2000, 72, 5590-5599). It is based on depth profiling of doped ice crystals epitaxially grown on Ru(001) by laser resonant desorption (LRD). Using this method, Livingston et al. obtained a value of the diffusion coefficient of the HCl hydrate in ice at 190 K of about 5 x 10(-11) cm2/s. We argue here that this value is many orders of magnitude higher than what could be expected from literature values, which are not reported in sufficient detail by Livingston et al. We investigate the possibilities that their high value could be due to (1) diffusion in defects in the ice, which would be present in very high concentrations because of the ice growth method; and (2) the fact that diffusion of high concentrations of HCl in ice at 190 K forms an amorphous HCl:H2O solid mixture, where HCl diffusion is fast. We present new infrared spectroscopic data on solid HCl:H2O mixtures that confirm that such mixtures can indeed be formed in an amorphous state at 190 K. Our proposed interpretation is that by depositing large amounts of HCl on epitaxially grown ice, Livingston et al. created a superficial amorphous binary mixture and that fast diffusion of HCl in the ice, possibly accelerated by a high defect density, produced an amorphous HCl:H2O mixture. We conclude that the processes studied by Livingston et al. are different from those involved in the atmospheric and cryospheric sciences, and that their data, obtained by depth profiling using LRD, probably cannot be applied to those fields.

Specific surface area of snow samples determined by CH4 adsorption at 77 K and estimated by optical microscopy and scanning electron microscopy.

Snow is a divided medium that can adsorb atmospheric trace gases. Evaluating the impact of the snow cover on atmospheric chemistry therefore requires the knowledge of the specific surface area (SSA) of snow. This paper compares the results of three methods used to measure or estimate the SSA of four snow samples: CH4 adsorption at 77 K, optical microscopy (OM), and scanning electron microscopy (SEM, used only on two samples). Within error bars, CH4 adsorption and OM yield similar results on three of the four snow samples. Values for the 4th sample are within a factor of 2. For both samples where CH4 adsorption, OM, and SEM are used, all three methods yield similar results, but CH4 adsorption always has a better accuracy and a much better precision. Thus, despite its ease of use, estimates from OM images are often not accurate enough to monitor the evolution of snow SSA. The main sources of error in the OM method are the difficulty to determine snow crystal thicknesses and to take into account the topography of the snow crystal surface. The combination of CH4 adsorption and OM or SEM can provide useful information on the evolution of both the SSA and the shape of snow crystals. This will be useful to evaluate the respective contributions of adsorption/desorption and sublimation/condensation processes to the impact of the snow cover on atmospheric chemistry.

Reanalysis and New Measurements of N(2) and CH(4) Adsorption on Ice and Snow.

Numerous literature data indicate that the mean heat of adsorption of a monolayer of N(2) (DeltaQ(N(2))) on ice or snow at 77.15 K, determined by volumetric methods, is highly variable, suggesting that ice surface properties strongly depend on its mode of formation and its thermal history. Less numerous data on CH(4) adsorption show smaller variations of DeltaQ(CH(4)). If such variations are real, the extrapolation to atmospheric chemistry models of adsorption parameters measured on laboratory-made ice may be unwarranted. We have measured CH(4) adsorption on variable amounts of a crushed ice sample, to show that when the total surface area of the sample is below a threshold value, DeltaQ(CH(4)) decreases. We identify the cause of this artifact as an error in the molar budget, because the temperature gradient in the tube connecting the introduction and expansion volumes is not taken into account. Performing an adequate molar budget suppresses this artifact, except for ice samples with very small total surface areas, where the resolution of the manometer becomes a limiting factor and a further decrease in DeltaQ(CH(4)) is observed. Error in DeltaQ(gas) results in large errors in surface area, and we suggest that the value of DeltaQ(gas) obtained can be used to test the reliability of the surface area measurement. Copyright 2000 Academic Press.

Modulation of N-nitrosomethylbenzylamine bioactivation by diallyl sulfide in vivo.

Diallyl sulfide (DAS), a major component of garlic oil, is an inhibitor of tumorigenesis by various metabolically activated carcinogens. In rats, pretreatment with DAS has been observed to suppress completely the induction of oesophageal neoplasms by N-nitrosomethylbenzylamine (NMBzA) (Wargovich et al. (1988) Cancer Res., 48, 6872-6875). This communication reports the effects of DAS on overall NMBzA metabolism and on DNA methylation of NMBzA in vivo under conditions equivalent to a single treatment of the chemoprevention assay. Male Fischer 344 rats received a single i.g. dose of DAS (200 mg/kg body wt) followed by an s.c. injection of [methyl-14C]NMBzA (3.5 mg/kg). In controls, exhalation of 14CO2 was complete within 5 h (t1/2max = 1.2 h), with 50% of the injected radioactivity recovered as 14CO2. When DAS was given 3 h prior to [methyl-14C]NMBzA, 49% of the injected radioactivity was released within 10 h (t1/2max = 3 h). When DAS was administered 18 h before the carcinogen, 42% of [methyl-14C]NMBzA was converted to 14CO2, with exhalation complete after 6 h (t1/2max = 1.8 h). We further examined the effects of acute doses of 10-200 mg/kg of DAS on DNA methylation by a single dose of NMBzA (3.5 mg/kg; survival time, 6 h) administered 3 h later. At 200 mg/kg, DAS inhibited the formation of O6-methyldeoxyguanosine (O6-MEdG) in oesophagus (-26%), nasal mucosa (-51%), trachea (-68%) and lung (-78%). In liver, levels of 7-MEdG were reduced by 43%. Decreases in DNA methylation were proportional to dose for > 25 mg/kg of DAS in oesophagus, liver and nasal mucosa, for 25-200 mg/kg in trachea and 10-50 mg/kg in lung. The dose-activity relationship for inhibition by DAS of DNA methylation by NMBzA suggests that short-term modulation of carcinogen bioactivation in situ contributes to but may not be sufficient for the chemo-prevention of nitrosamine tumorigenesis by DAS.