The associations between substance use initiation and suicidal behaviors differed in the United States and France. These findings, placed into context, can assist the development and implementation of prevention strategies that seek to reduce the harmful consequences of early substance use among youth.

There is a gradient relationship between parental control and current consumption, especially among girls. Thus, there may be a need for parental control, whatever the family structure.

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The effects of glucagon (G) on proximal tubule reabsorption (PTR) and GFR seem to depend on a prior action of this hormone on the liver resulting in the liberation of a mediator and/or of a compound derived from amino acid metabolism. This study investigates in anesthetized rats the possible contribution of cAMP and urea, alone and in combination with a low dose of G, on phosphate excretion (known to depend mostly on PTR) and GFR. After a 60-min control period, cAMP (5 nmol/min ϫ 100 grams of body weight [BW]) or urea (2.5 mol/min ϫ 100 grams BW) was infused intravenously for 200 min with or without G (1.2 ng/min ϫ 100 grams BW, a physiological dose which, alone, does not influence PTR or GFR). cAMP increased markedly the excretion of phosphate and sodium ( ϩ 303 and ϩ 221%, respectively, P Ͻ 0.01 for each) but did not alter GFR. Coinfusion of cAMP and G induced the same tubular effects but also induced a 20% rise in GFR ( P Ͻ 0.05). Infusion of urea, with or without G, did not induce significant effects on PTR or GFR. After G infusion at increasing doses, the increase in fractional excretion of phosphate was correlated with a simultaneous rise in plasma cAMP concentration and reached a maximum for doubling of plasma cAMP. These results suggest that cAMP, normally released by the liver into the blood under the action of G, ( a ) is probably an essential hepatorenal link regulating the intensity of PTR, and ( b ) contributes, in conjunction with specific effects of G on the nephron, to the regulation of GFR. ( J. Clin. Invest. 1996. 98: 2251-2258.)

ContextSuicide is the second leading cause of death in adolescents and young adults in Europe. Reducing suicides is therefore a key public health target. Previous studies have shown associations between suicidal behaviors, depression and family factors.ObjectiveTo assess the role of family factors in depression and suicidality in a large community-based sample of adolescents and to explore specific contributions (e.g. mother vs. father; conflict vs. no conflict; separation vs. no separation) taking into account other risk factors.MethodsA cross-sectional sample of adolescents aged 17 years was recruited in 2008. 36,757 French adolescents (18,593 girls and 18,164 boys) completed a questionnaire including socio-demographic characteristics, drug use, family variables, suicidal ideations and attempts. Current depression was assessed with the Adolescent Depression Rating Scale (ADRS). Adolescents were divided into 4 groups according to suicide risk severity (grade 1 = depressed without suicidal ideation and without suicide attempts, grade 2 = depressed with suicidal ideations and grade 3 = depressed with suicide attempts; grade 0 = control group). Multivariate regressions were applied to assess the Odds Ratio of potential risk factors comparing grade 1, 2 or 3 risk with grade 0.Results7.5% of adolescents (10.4% among girls vs. 4.5% among boys) had ADRS scores compatible with depression; 16.2% reported suicidal ideations in the past 12 months and 8.2% reported lifetime suicide attempts. Repeating a year in school was significantly associated to severity grade of suicide risk (1 and 3), as well as all substance use, tobacco use (severity grades 2 and 3) and marijuana use (severity grade 3), for girls and boys. After adjustment, negative relationships with either or both parents, and parents living together but with a negative relationship were significantly associated with suicide risk and/or depression in both genders (all risk grades), and Odds Ratios increased according to risk severity grade.ConclusionFamily discord and negative relationship with parents were associated with an increased suicide risk in depressed adolescents. So it appears essential to take intrafamilial relationships into account in depressed adolescents to prevent suicidal behaviours.

Synthesis of arginine (Arg) from citrulline (Cit) by the kidney is a major source of Arg for the body. The high level of plasma Cit in chronic renal failure is often thought to result from the impairment of the renal conversion of Cit to Arg. To verify this assumption, we performed two studies in Sprague-Dawley rats with 5/6 nephrectomy (CRF rats) and in sham-operated rats (CONT rats). In study I synthesis of Arg by isolated proximal convoluted tubules (PCT; the nephron segment exhibiting the highest Arg synthesis) was measured in vitro with two concentrations of Cit (200 or 50 microM) corresponding to those observed in plasma of rats with or without renal failure. In study II the net renal uptake of Cit and release of Arg were determined in vivo by measuring PAH clearance and arterial and renal venous Arg, and Cit concentrations in anesthetized rats. The in vitro results showed that Arg synthesis increased only in proportion to the hypertrophy of remnant PCT (+50%), and was highly and similarly dependent on Cit concentration in PCT of remnant and normal kidneys (Arg production with 200 microM Cit was 3 times higher than with 50 microM Cit for both CONT and CRF). The in vivo results showed that renal Cit uptake and Arg release were not altered in CRF: -286 +/- 28 versus -326 +/- 16 nmol Cit.min-1 (NS), and + 390 +/- 47 versus + 399 +/- 22 nmol Arg.min-1 (NS) in CONT and CRF rats, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

This study suggests an association between positive reactions to first cannabis uses and risk of life-time cannabis dependence, this variable having a central role among, and through, other risk factors.