Probing the Biosynthesis of Vitamin B₁₂

No abstract

Improving the Supply Distribution and Use of Antimalarial Drugs by the Private Sector in Tanzania. Report prepared for the National Malaria Control Programme, United Republic of Tanzania

Private pharmacies or shops are the source of 60% of the drugs bought to treat suspected cases of malaria. At the same time 59% of children fail to be treated within 24 hours of onset. The private sector is the primary source for antimalarials, but parents and carers are failing to administer those drugs sufficiently early to minimise morbidity and mortality. This review focused on the way in which antimalarial drugs reach the patient. It also examined ways in which the delivery system could be improved and how the private facilities can become more effective sources of both drugs and advice. It has found that there are many problems with the way that drugs are distributed. Many unregistered drugs are readily available, and poor storage conditions are likely to reduce the efficacy of drugs even if they were of good quality at the time of manufacture. For many people the cost of even the cheapest antimalarial is an issue and purchase of part doses is common. The knowledge of the staff in pharmacies is poor and in shops woefully inadequate. Nonetheless most people use shops and private pharmacies as their source for drugs. There are two overarching requirements: • First of all the needs and capabilities of the private sector must always be taken into account before any decision is made about how to make antimalarials more available. • Secondly, educating the staff and public will only be achieved through a subtle communications package regularly repeated and brought up to date. For example we found that many workers in Part II pharmacies remain in post for no more than one year. Unlike their counterparts in the public sector, staff in the private sector do not find incentives in attending training courses. Staff in the public sector spend so much time on courses that their time to actually implement what they have learned is limited. To reach the private sector staff will require subtler and more cost effective methods. The report is full of detailed recommendations for the improvement of the supply systems and for educating both staff and public

An Unusual Mode of DNA Duplex Association: Watson-Crick Interaction of All-Purine Deoxyribonucleic Acids

SummaryNucleic acid duplexes associating through purine-purine base pairing have been constructed and characterized in a remarkable demonstration of nucleic acids with mixed sequence and a natural backbone in an alternative duplex structure. The antiparallel deoxyribose all-purine duplexes associate specifically through Watson-Crick pairing, violating the nucleobase size-complementarity pairing convention found in Nature. Sequence-specific recognition displayed by these structures makes the duplexes suitable, in principle, for information storage and replication fundamental to molecular evolution in all living organisms. All-purine duplexes can be formed through association of purines found in natural ribonucleosides. Key to the formation of these duplexes is the N3-H tautomer of isoguanine, preferred in the duplex, but not in aqueous solution. The duplexes have relevance to evolution of the modern genetic code and can be used for molecular recognition of natural nucleic acids