Nalmefene and its use in alcohol dependence.

Nalmefene is the first available drug approved in the E.U. to reduce alcohol use in alcohol-dependent patients. Reduction in alcohol use in heavy drinkers diminishes mortality risk and socio-economic burden. Nalmefene has shown efficacy at 6 months in alcohol-dependent patients with high or very high drinking risk levels in reducing total alcohol consumption (-7.6 g/day [95% confidence interval (CI): -11.6 to -3.5]; P = 0.0003), heavy drinking days (-2.00 days/month [95% CI: -3.00 to -1.00]; P ⟨ 0.00001) and other secondary outcome measures such as γ-glutamyl transferase, alanine aminotransferase, drinking risk level and Clinical Global Impression. It is generally well tolerated and has limited contraindications and interactions. As-needed dosage is a novel concept in the addictions field, which may overcome limitations of traditional regimens. In the pivotal trials, nalmefene was taken 52% of the days and compliance with the as-needed treatment regimen was good (above 80% of the days) in 68% of the nalmefene-treated patients. A new pharmacological approach combined with a brief psychosocial intervention for alcoholism is available and appears to be feasible, safe and efficacious.

Purity, antigenicity and immunogenicity of the hepatitis B surface antigen purified by five different methods.

Five published methods for the purification of HBsAg from plasma were compared for specific activity (SA), degree of purification, and yield. The SA value was determined by dividing the reciprocal of the end point dilution per milliliter as determined using a commercial radioimmunoassay (AUSRIA II; Abbott Laboratories, North Chicago, IL) by the protein concentration quantitated by the Lowry method. HBsAg purified by two consecutive isopycnic ultracentrifugation separations in KBr and one rate-zonal separation in sucrose using a zonal rotor (Ti-14, Beckman, Palo Alto, CA) yielded a preparation which gave the highest SA value, degree of purification and yield as compared to four other methods. Each purified preparation was adsorbed to alum adjuvant and injected into mice to determine the immunogenic dose at which 50% of the animals elicited an anti-HBs response (ID50). The zonal rotor method resulted in the lowest ID50 value (365 ng/ml) supporting the highest SA value. Furthermore, SDS polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis revealed that this preparation had the greatest number of HBsAg-specific polypeptides (N = 7) and the fewest contaminating polypeptides (N = 5). The contaminating proteins were identified as alpha-2-macroglobulin, heavy chains of IgG and IgM, immunoglobulin kappa chain, and albumin.

Kinetic mechanism of chicken liver xanthine dehydrogenase.

The kinetic behaviour of chicken-liver xanthine dehydrogenase (xanthine/NAD+ oxidoreductase; EC 1.2.1.37) has been studied. Steady-state results, obtained from a wide range of concentrations of substrates and products, were fitted by rational functions of degree 1:1, 1:2, 2:2 and 3:3 with respect to substrates, and 0:1, 1:1, 0:2 and 1:2 with regard to products, using a non-linear regression program which guarantees the fit. The goodness of fit was improved using a computer program that combines model discrimination, parameter refinement and sequential experimental design. The AIC and F tests were also used for model discrimination. For comparative purposes, the xanthine/oxygen oxidoreductase reaction was also studied. From the functions which give the maximum improvement, the complete rate equation was deduced. The significance of the terms was stated by the above methods. It was concluded that xanthine dehydrogenase requires a minimum mechanism of degree 1:1 for xanthine, 2:2 for NAD+, 1:1 for uric acid and 1:2 for NADH in the xanthine/NAD+ oxidoreductase reaction. These are the minimum degrees required but a rate equation of higher degree is not excluded.