Pteridine reductase (PTR1): initial structure-activity relationships studies of potential leishmanicidal arylindole derivatives compounds.

Leishmaniasis is a public health concern, especially in Brazil and India. The drugs available for therapy are old, cause toxicity and have reports of resistance. Therefore, this paper aimed to carry out initial structure-activity relationships (applying molecular docking and dynamic simulations) of arylindole scaffolds against the pteridine reductase (PTR1), which is essential target for the survival of the parasite. Thus, we used a series of 43 arylindole derivatives as a privileged skeleton, which have been evaluated previously for different biological actions. Compound 7 stood out among its analogues presenting the best results of average number of interactions with binding site (2.00) and catalytic triad (1.00). Additionally, the same compound presented the best binding free energy (-32.33 kcal/mol) in dynamic simulations. Furthermore, with computational studies, it was possible to comprehend and discuss the influences of the substituent sizes, positions of substitutions in the aromatic ring and electronic influences. Therefore, this study can be a starting point for the structural improvements needed to obtain a good leishmanicidal drug.

2-Arylindoles: a privileged molecular scaffold with potent, broad-ranging pharmacological activity.

Privileged structures bind to multiple receptors with high affinity, thus aiding the development of novel biologically active compounds. Indoles are classed as privileged structures, and as a result of the indole nucleus being present in a broad range of biologically active molecules, it has been suggested that indoles probably represent the most important of all structural classes in drug discovery. Amongst the indole class of compounds is a particular subset - 2-arylindoles - which appear to be a most promising lead for drug development. This review summarises the wide-ranging activities of 2-arylindoles and some of their important biological activities reported in the literature over the past two decades.

Versatility of a new bioinorganic catalyst: palladized cells of Desulfovibrio desulfuricans and application to dehalogenation of flame retardant materials.

The versatility and reaction specificity of a novel bioinorganic catalyst is demonstrated in various reactions. Palladized cells (bioPd) of the sulphate-reducing bacterium Desulfovibrio desulfuricans showed an increased product selectivity and a catalytic activity comparable to a commercial Pd catalyst in several industrially relevant hydrogenations and hydrogenolyses (reductive dehalogenations). The ability of palladized cells to promote the reductive debromination of a polybrominated diphenyl ether (PBDE #47) is demonstrated, although chemically reduced Pd(II) and commercial Pd(0) were more effective debromination agents. Polybrominated diphenyl ethers are being supplanted as flame retardants by other compounds, e.g. tris(chloroisopropyl)phosphate (TCPP), the concentration of which was seen to increase approximately 10-fold in groundwater samples between 2000 and 2004. BioPd dechlorinated TCPP in groundwater samples with >90% recovery of free chloride ion, and was five times more effective than using commercial Pd(0) catalyst. Examination of the spent groundwater using 31P NMR showed a phosphorus species novel to the bioPd-treated solution, which was not evident in a commercial reference sample of TCPP.

Quality control in the development of coagulation factor concentrates.

Limitation of process change is a major factor contributing to assurance of quality in pharmaceutical manufacturing. This is particularly true in the manufacture of coagulation factor concentrates, for which presumptive testing for poorly defined product characteristics is an integral feature of finished product quality control. The development of new or modified preparations requires that this comfortable position be abandoned, and that the effect on finished product characteristics of changes to individual process steps (and components) be assessed. The degree of confidence in the safety and efficacy of the new product will be determined by, amongst other things, the complexity of the process alteration and the extent to which the results of finished product tests can be considered predictive. The introduction of a heat-treatment step for inactivation of potential viral contaminants in coagulation factor concentrates presents a significant challenge in both respects, quite independent of any consideration of assessment of the effectiveness of the viral inactivation step. These interactions are illustrated by some of the problems encountered with terminal dry heat-treatment (72 h. at 80 degrees C) of factor VIII and prothrombin complex concentrates manufactured by the Blood Products Laboratory.

Response to infusions of polyelectrolyte fractionated human factor VIII concentrate in human haemophilia A and von Willebrand's disease.

Factor VIII was purified from cryoprecipitate by ion exchange chromatography on solid phase polyelectrolyte E-5 (PE-E5). The product was highly purified (3.5 u VIII:C/mg protein) compared to conventional concentrate (0.3 u VIII:C/mg protein) with low fibrinogen, low isoagglutinin titre, and a ratio of factor VIII coagulant activity (VIII:C) to factor VII related antigen (VIIIR:Ag) of 16:1. Trial infusions of this material (PE VIII) were given to three patients with severe haemophilia A and one patient with homozygous von Willebrand's disease. These patients also each received separate infusions of intermediate purity concentrate (IPC) for comparison. There were no adverse effects. The mean half life of VIII:C after PE VIII infusion in the haemophiliacs was 10.9 h and after IPC was 12.1 h, a statistically insignificant difference. The survival of factor VIII coagulant antigen (VIII:CAg) was similar to that of VIII:C. In contrast, the half life of VIII:C and of VIII:CAg was very short after infusion of PE VIII in the patient wih von Willebrand's disease (2.4 h). IPC when infused in this patient produced a typical secondary rise of VIII:C. Two bleeding episodes in severe haemophiliacs were satisfactorily treated with PE VIII. PE-E5 deserves further study as a means of preparing clinical concentrates of factor VIII.

Evaluation of an AutoAnalyzer method for quantitating anti-A and anti-B haemagglutinins in factor VIII preparations.

The continuous flow principle employed in the Technicon AutoAnalyzer has been adapted for the assay of anti-A and anti-B. The method has an acceptable degree of reproducibility and has been used, principally, for the quantitation of anti-A and anti-B in factor VIII concentrates of intermediate activity. It is, however, a method that can be applied to the assay of these antibodies in serum samples.

A factor VII concentrate for therapeutic use.

A concentrate of factor VII suitable for therapeutic use has been prepared from human plasma by a method forming part of a comprehensive scheme of large-scale plasma fractionation. Factor VIII was separated as cryoprecipitate and factors II, IX and X were adsorbed on DEAE-cellulose. Most of the factor VII remained in the supernatant. By batch adsorption on DEAE-Sepharose, followed by elution on a chromatographic column, factor VII was concentrated about 25-fold, and purified about 50-fold compared with original plasma, without the need for further dialysis or concentration steps. Data are presented from 10 batches, each from 80-120 kg plasma. Following doses of factor VII to six congenitally deficient patients, the mean rise in plasma factor VII was 95-100% of theoretical; the half-disappearance time was about 4 h. The treatment of four patients with acquired deficiency of factor VII is also described. No untoward side effects were observed.

Preparation of improved cryoprecipitated factor VIII concentrate. A controlled study of three variables affecting the yield.

The effect on cryoprecipitate factor VIII recovery of three imortant variables has been investigated. The design of the study was such as to eliminate, for the purpose of internal comparisons, spurious effects such as those due to the variation in factor VIII levels in donor plasma. The choice of anticoagulant was shown to be of particular significance, plasma collected into CPD anticoagulant giving higher cryoprecipitate factor VIII yield thoughout the study. The effect on cryoprecipitate factor VIII recovery of delay before separation and freezing of the plasma was more complex. Very fresh plasma (separated and frozen within 2 h of collection) gave the highest recovery of factor VIII, but no difference was detected between cryoprecipitate factor VIII recovery of plasma separated and frozen at 4 h and at 18 h after blood collection. Controlled rapid thawing of the plasma was also shown to be advantageous, at least for the preparation of cryoprecipitates from plasma anticoagulated with CPD anticoagulant.

A factor VIII concentrate of intermediate purity and higher potency.

A fractionation method has been modified to produce a factor VIII concentrate of intermediate purity and a potency of about 12 iu/ml, suitable for injection by syringe. The solubility, ease of filtration and purity of the concentrate have been improved by including a stage in which contaminants are precipitated at controlled temperature, pH and ionic strength. A summary of the first 50 production-scale batches is presented. Plasma can be harvested from whole blood and frozen within eight hours of donation, or after overnight storage of whole blood, with no significant difference in overall yield.

The assay of prekallikrein activator in human blood products.

An assay for the determination of prekallikrein activator (PKA) in human blood products is described. Kallikrein released from a prekallikrein substrate preparation by PKA in the sample is determined using the synthetic substrate S-2302 (H-D-Pro-Phe-Arg-pNA). The PKA content of the sample is quantitated by interpolation from a standard line obtained using a reference preparation of plasma protein fraction (PPF). Endogenous kallikrein is estimated and an adjustment made for its contribution to the apparent PKA content of the sample. The results of determinations on a number of PPF, immunoglobulin and coagulation factor preparations are presented and discussed.

Testing for potential thrombogenicity of prothrombin complex concentrates.

The methods used in the author's laboratory for testing for potential thrombogenicity in prothrombin complex concentrates are described and compared critically. Alternative methods of presenting the results of these test systems are discussed. Changes in fractionation procedure which have resulted in improved performance of concentrates in one or more of the tests are discussed.

Methods of assessing factor VIII content of stored fresh frozen plasma intended for preparation of factor VIII concentrates.

Minimally destructive methods were sought to assess the factor VIII content of fresh frozen plasma intended for large-scale fractionation and stored in five-liter polyethylene packs after pooling approximately 23 plasma donations. Although factor VII distribution in the frozen pack was not perfectly homogenous, a central "core" through the frozen pack gave a representative sampel of the entire contents of the pack. Coring was compared with other methods of pack sampling before large-scale cryoprecipitation. The survival of factor VIII was studied in three grades of stored plasma which had been separated and frozen within 4 hours, 8 hours, and 18 hours of blood donation. Plasma frozen after overnight storage of blood is a satisfacory starting material for the preparation of factor VIII and factor IX concentrates.

A five year experience of the use of factor IX type DE(I) concentrate for the treatment of Christmas disease of Oxford.

A survey is presented of the use of the Oxford type DE(I) II-IX-X concentrate in the treatment of Christmas disease in Oxford from January 1970 to September 1974. 72 different patients were treated with a total of 2436 bottles of this concentrate from 143 different batches (each bottle containing 800-1000 units of factor IX). Although most doses were given for the treatment of minor haemorrhages into joints and muscles, 717 bottles of concentrate were used to treat 11 patients who underwent 14 major surgical operations. No episode of intravascular clotting or pulmonary embolism was seen in any patient receiving the concentrate. A detailed study of the plasma levels of factor V, VIII, total progressive antithrombin, platelets and fibrinogen degradation products was carried out before and after transfusion of type DE(I) concentrate in 14 patients. No significant alteration in those factors was found after the transfusion.