H-NS, a protein found in Gram-negative bacteria, is involved in structuring the bacterial chromosome and acts as a global regulator for the expression of a wide variety of genes. These functions are correlated with both its DNA-binding and oligomerization properties. We have identified the minimal dimerization domain of H-NS, a 46 amino acid-long N-terminal fragment, and determined its structure using heteronuclear NMR spectroscopy. The highly intertwined structure of the dimer, reminiscent of a handshake, defines a new structural fold, which may offer a possibility for discriminating prokaryotic from eukaryotic proteins in drug design. Using mutational analysis, we also show that this N-terminal domain actively contributes to DNA binding, conversely to the current paradigm. Together, our data allows us to propose a model for the action of full length H-NS.

Structural biology, homology modelling and rational drug design require accurate three-dimensional macromolecular coordinates. However, the coordinates in the Protein Data Bank (PDB) have not all been obtained using the latest experimental and computational methods. In this study a method is presented for automated re-refinement of existing structure models in the PDB. A large-scale benchmark with 16 807 PDB entries showed that they can be improved in terms of fit to the deposited experimental X-ray data as well as in terms of geometric quality. The re-refinement protocol uses TLS models to describe concerted atom movement. The resulting structure models are made available through the PDB_REDO databank (http://www.cmbi.ru.nl/pdb_redo/). Grid computing techniques were used to overcome the computational requirements of this endeavour.

The co-occurrence of substance use disorders (SUDs) and anxiety disorders has been now well established. This association is frequent and can be explained by three models: the shared vulnerability factors model, the self-medication model, and the substance-induced model. General population epidemiological studies provide strong evidence of the frequency of the association for the most used substances: tobacco, alcohol, cannabis, and to a lesser extent sedatives, opiates, and cocaine. For substances that are less commonly used in the general population, the frequency of the co-occurrence can more precisely be studied in clinical samples. We provide the most recent literature results on the association of SUDs and anxiety, and evidence for one explicative model or the other when available. For substances with sedative properties (alcohol, benzodiazepines, cannabis, opioids), both evidence for a self-medication and for a toxic effect exist. For substances with psychostimulant properties (tobacco, cocaine, and amphetamines), the literature favors the toxic hypothesis to explain the association with anxiety disorders. We give practical steps for the recognition of these dual diagnoses and present therapeutic issues, although the strategies are rarely evidence based.

AIMSMethadone is characterized by wide intersubject variability regarding the dose needed to obtain full therapeutic response. We assessed the influence of sociodemographic, ethnic, clinical, metabolic and genotypic variables on methadone maintenance dose requirement in opioid-dependent responder patients. METHODSEighty-one stable patients (60 men and 21 women, 43.7 ± 8.1 years old, 63.1 ± 50.9 mg day À1 methadone), divided into quartiles with respect to the median daily dose, were enrolled and underwent clinical examination, treatment history and determination of liver/intestinal cytochrome P450 (CYP) 3A4 activity measured by the midazolam test, R,S-methadone trough concentration and clinically significant polymorphisms of the OPRM1, DRD2, COMT, ABCB1, CYP2B6, CYP3A5, CYP2C19 and CYP2D6 genes. RESULTSMethadone maintenance dose was correlated to the highest dose ever used (r 2 = 0.57, P < 0.0001). Fractioned methadone intake (odds ratio 4.87, 95% confidence interval 1.27-18.6, P = 0.02), bodyweight (odds ratio 1.57, 95% confidence interval 1.01-2.44, P = 0.04), history of cocaine dependence (80 vs. 44 mg day À1 in neveraddict patients, P = 0.005) and ethnicity (Asian > Caucasian > African, P = 0.04) were independently associated with high-dose methadone in multiple regression analysis. A modest correlation was observed between liver/intestinal CYP3A4 activity and methadone dose at steady state (Spearman rank correlation coefficient [r s ] = 0.21, P = 0.06) but not with highest dose ever used (r s = 0.15, P = 0.18) or dosenormalized R,S-methadone trough concentrations (r s = À0.05, P = 0.64). WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Overall, 30-80% of patients on methadone maintenance treatment are still receiving doses that are too low to be effective and experience withdrawal symptoms or decreased methadone efficacy for part of the dosing interval and/or have persistent heroin use or dropouts because of relapses.• The role of several genetic polymorphisms, including the CYP2B6, CYP2C19, CYP2D6 and MDR1 genotypes, on steady-state concentrations of methadone enantiomers was also controversial in clinical studies.• These studies did not simultaneously address the influence of sociodemographic and clinical variables and concomitant medications on methadone maintenance treatment with a multivariate approach. Concomitant CYP3A4 inhibitors only affected the relationship between methadone dose and R,S-methadone trough concentration. None of the genetic polymorphisms explored was predictive of the methadone maintenance dose. CONCLUSIONSMethadone maintenance dose was predicted by sociodemographic and clinical variables rather than genetic polymorphisms or liver/intestinal CYP3A4 activity in stable patients.

Immediate and serial measurements of blood chloroquine concentrations are better than plasma for predicting cardiovascular severity of chloroquine poisonings.

Introduction Prognostic factors in intentional insulin selfpoisoning and the significance of plasma insulin levels are unclear. We therefore conducted this study to investigate prognostic factors in insulin poisoning, in relation to the value of plasma insulin concentration.

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