摘要:

Passive immunoprophylaxis with hepatitis B immunoglobulin is used to reduce the risk of infection of grafts after liver transplantation and also to protect newborn children of hepatitis B virus-infected mothers. The use of hepatitis B immunoglobulin is associated with the emergence of variant viruses or escape mutants that have specific amino acid substitutions in immunodominant epitopes. Under these circumstances, high serum titres of the virus may be observed in the context of apparently protective levels of antibody to hepatitis B surface antigen. The potential impact of hepatitis B surface antigen variation on vaccination strategies remains a contentious issue. As the burden of hepatitis B virus is dramatically reduced by major vaccination programmes, a greater proportion of carriers will demonstrate hepatitis B surface antigen variation from wild-type. The degree of protection afforded by current vaccines from subsequent infection by variants of the virus is unknown. Concern is raised over the potential impact of hepatitis B surface antigen variation on hepatitis B virus polymerase inhibitor susceptibility, and the reduced sensitivity of current antigen assays for detection of hepatitis B surface antigen variants.

ISSN:0951-7375    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Problems associated with the current therapies of sleeping sickness include toxicity, resistance and a lack of a guaranteed supply. However, no new formulations are close to gaining a licence for clinical use and relatively few compounds have been shown to be effective in experimental systems. Many potentially good biochemical targets for drugs have been identified. Some of these have been validated and lead compounds have been developed. However, the biology of trypanosomes means that various pharmacological demands must be met in developing new trypanocides for clinical use. Foremost among these problems is the blood-brain barrier, across which trypanocides must cross to reach parasites in the cerebrospinal fluid.The principal problem, however, relates not to biological difficulties, which are technically surmountable, but to economics. Put simply, most representatives of the pharmaceutical industry believe that selling drugs to the victims of sleeping sickness will not yield sufficient income to justify expenses needed for the development of novel reagents. Only when this economic barrier can be lowered will new drugs emerge for use against sleeping sickness.

ISSN:0951-7375    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

For 40 years scientists have hotly debated the questions of how chloroquine kills malarial parasites and how resistance to this once first-line antimalarial drug has evolved. While an end to these debates is not in sight, as a result of the complexity of the subject, new findings have come forward that give the discussion a new direction. In this paper we will summarize current knowledge on chloroquine's antimalarial mode of action and the genesis of the resistant phenotype in the human malarial parasitePlasmodium falciparum, with special emphasis on the most recent developments in this field.

ISSN:0951-7375    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The low cure rates obtained with praziquantel in a Senegalese focus of schistosomiasis can best be interpreted on the basis of epidemiological factors, and are unlikely to be connected with any drug resistance in the parasite. Schistosome isolates obtained in Egypt from uncured patients present evidence of lower susceptibility to the drug, albeit to a rather limited extent. Similarly, laboratory schistosomes subjected to repeated passages under drug pressure are partly insensitive to the drug. Oxamniquine is at present the only available alternative to praziquantel. Research and development of new antischistosomal drugs is urgently needed.

ISSN:0951-7375    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0951-7375    

出版商:OVID    

年代:2000

数据来源: OVID