Docking and scoring--theoretically easy, practically impossible?

Structure-based Drug Design (SBDD) is an essential part of the modern medicinal chemistry, and has led to the acceleration of many projects, and even to drugs on the market. Programs that perform docking and scoring of ligands to receptors are powerful tools in the drug designer's armoury that enhance the process of SBDD. They are even deployed on the desktop of many bench chemists. It is timely to review the state of the art, to understand how good our docking programs are, and what are the issues. In this review we would like to provide a guide around the reliable aspects of docking and scoring and the associated pitfalls aiming at an audience of medicinal chemists rather than modellers. For convenience, we will divide the review into two parts: docking and scoring. Docking concerns the preparation of the receptor and the ligand(s), the sampling of conformational space and stereochemistry (if appropriate). Scoring concerns the evaluation of all of the ligand-receptor poses generated by docking. The two processes are not truly independent, and this will be discussed here in detail. The preparation of the receptor and ligand(s) before docking requires great care. For the receptor, issues of protonation, tautomerisation and hydration are key, and we will discuss current approaches to these issues. Even more important is the degree of sampling: can the algorithms reproduce what is observed experimentally? If they can, are the scoring algorithms good enough to recognise this pose as the best? Do the scores correlate with observed binding affinity? How does local knowledge of the target (for example hinge-binding to a kinase) affect the accuracy of the predictions? We will review the key findings from several evaluation studies and present conclusions about when and how to interpret and trust the results of docking and scoring. Finally, we will present an outline of some of the latest developments in the area of scoring functions.

[Impact of a quality approach for transfusion safety on prescription, circuit optimization, traceability]. / Impact d'une démarche qualité en sécurité transfusionnelle sur la prescription, l'optimisation des circuits, la traçabilité. Expérience du CHRU de Lille.

The Quality Assessment Program undertaken at the Regional University Hospital of Lille benefits from previous experience making management of this project possible: continuing education, preliminary initiation into the quality approach, and existing reference systems. The aims are to master the rates of outdated and no longer efficient red cell concentrates, to control red cell concentrate delivery time, to validate the refrigeration line integrity and to ensure a flawless marking out process. The process studied is transverse, with those taking part in it belonging to several professional categories. The method will consist in a process identification, its description and characterization according to FMECA (Failure Mode Effects and Criticality Analysis), the creation of a new process and its improvement. Thus failures should be identified and classified hierachically. The corrective actions will consist in communication aids, an education program, blood product transport and blood depot reorganization, data processing improvement and medical equipment acquisition. Quality indicators are developed according to the objectives of the study, and progress indicators are developed as a periodical assessment of blood transfusion practice. This ambitious project relies on the involvement of Hospital Management and referent network. These referents facilitate the improvement processes for those taking part in this process.

[Extracorporeal shockwave lithotripsy and hemophilia: apropos of a case]. / LEC et hémophilie: à propos d'un cas.

We report pelvis calculi fragmentation through the use of extracorporeal shock wave lithotripsy in a patient with mild hemophilia B. The EDAP LT 01 lithotriptor was used without incident. We review other reported cases in the literature.

[Donath-Landsteiner hemolytic anemia. Physiopathological, diagnostic and therapeutic aspects]. / Anémie hémolytique de Donath et Landsteiner. Aspects physiopathologiques, diagnostiques et thérapeutiques.

Donath-Landsteiner hemolytic anemia accounts for one third of all immunologic hemolytic syndromes in pediatric patients. Diagnosis is suggested by results of the direct Coombs test which is positive with anti-C3d, evidence of erythrophagocytosis on admission blood smears, and results of the Donath-Landsteiner test. Anti-P specificity should be routinely looked for. Management, required once the diagnosis is established, is symptomatic. Warmed red blood cell concentrates should be used for blood transfusions. Exposure to cold should be avoided. Use of maintenance corticosteroid therapy is no longer acceptable.

Clinical and biological evaluation in von Willebrand's disease of a von Willebrand factor concentrate with low factor VIII activity.

This study was carried out to assess the clinical efficacy in von Willebrand's disease (vWD) of a new, very high purity (VHP), solvent/detergent (SD)-treated, vWF concentrate (VHP Human von Willebrand Factor Concentrate, Biotransfusion) characterized by a high specific ristocetin cofactor (vWF:RCo) activity and a low factor VIII (FVIII) coagulant activity (FVIII:C). Nine patients (four type I, one type IIA, one type IIB, one type IIC, one type III and one acquired type II) were infused on 13 occasions including a pharmacokinetic study. Satisfactory haemostasis was achieved in all cases, including the treatment of spontaneous haemorrhages and the prevention of bleeding following surgery. The bleeding time was corrected for 6-12 h in 6/9 patients and shortened in the others. Furthermore, it was shown that the plasma vWF multimeric pattern of types II and III patients was greatly improved. When measured in eight patients 1 h after infusion, the vWF:RCo recovery was 77.3 (+/- 10.7)% while the F VIII:C recovery was strikingly higher (876 +/- 906%). This high recovery is likely related to the predominant 'pseudo-synthesis' of FVIII following the restoration of normal vWF levels. Maximum levels of FVIII:C occurred 6-12 h after the first infusion and normal levels of FVIII:C were maintained throughout the treatments with a dosage of 26-39 IU/kg vWF:RCo and only 0.2-5 IU/kg FVIII:C. The half-lives of the vWF-related parameters determined in a type III vWD patient were 20.6 h for vWF antigen, 17.8 h for vWF:RCo, 14 h for the high molecular weight multimers of vWF, 55.3 h for FVIII:Ag and 74 h for FVIII:C. In conclusion, it does not appear necessary that vWF concentrates intended for the treatment of vWD should contain FVIII in addition to vWF to be clinically effective in most patients.

Desmopressin is not always effective in mild haemophilia A patients undergoing urological surgery: the need of standardized protocols.

Desmopressin may be an efficient haemostatic treatment for mild A haemophiliacs because its infusion raises plasma factor VIII level. We report the use of desmopressin in five mild haemophilia A patients undergoing urological surgery. They all received a preoperative infusion (0.3 microg kg(-1), i.v.) 1 h before incision followed by repeated injections at 12- or 24-h intervals according to the severity of the procedure. Nevertheless, four patients presented a postoperative bleeding requiring again surgery performed for 3 of them under clotting factor concentrate instead of desmopressin. The occurrence of haemorrhage was not always correlated with particularly low plasma factor VIII level. Surgical management of urological procedures with desmopressin in mild haemophilia A patients requires standardized protocols.