Contraception with intrauterine devices

A review of the history of contraception with intrauterine devices, characteristics of present devices, and directions of current research is presented. The serious need for population control is not yet being met by today's inconvenient, ineffective, or unsafe methods. Intrauterine devices have been best for international family planning programs because they are cheap, easily installed, and provide continuous protection. There are many different models that have been and are being used, with different effectiveness and complication rates. The most commonly used today is the Lippes Loop, with a pregnancy rate of 2.8/100 years of woman use and an expulsion rate of 10.4. Most of these failures occur in the first few months of use, after which these rates are greatly reduced. The removal rate because of bleeding or pain for the Lippes device is 14.0. Other devices commonly used have pregnancy rates ranging 1.3-4.7, expulsion rates of 2.6-25.8, and removal rates of 13.5-22.1. Expulsion is directly related to the size and design of the IUD and the age and parity of t,e recipient. It is important to match the size of the device used to the individual characteristics of the patient. Research is seeking a design that will implant itself in the endometrium to resist expulsion, but not too deeply so that it is covered. Removal for bleeding and pain remains the most frequent complication of the IUD, and it partly depends on the skill of the inserting physician and how well the patient is psychologically prepared for side effects in the first months of use. Pregnancy is the most significant IUD complication. The key to an effective IUD is an understanding of its antifertility mechanism, which has thus far eluded researchers. The IUD prevents implantation of the blastocyst in the uterine wall, which may be due to a foreign-body reaction in the endometrium. IUDs with copper cause a greater reaction than plastic devices and provide hope for a very effective device; particularly the T-shaped design, which resists expulsion. The most promising new IUD is the Dalkon Shield. It has small projections that imbed in the endometrium and a broad surface for contact with the uterine wall. In preliminary experiments the pregnancy rate with this device was 1.1, the expulsion rate 2.3, and the removal rate 2.0, much lower than that with any other device yet developed. It is concluded that IUDs such as the Dalkon Shield can provide safe contraception with high effectiveness.     

FDA regulation of computerized cytology devices

When talking about computerized cytology devices, a "different" aspect of quality assurance must be addressed. Any medical device intended for in vitro diagnostic use in the United States must be cleared or approved by the Food and Drug Administration (FDA): the May 28, 1976, Medical Device Amendments to the Federal Food, Drug and Cosmetic Act granted authority to the FDA to regulate medical devices. The FDA regulatory process as it relates to computerized cytology devices is discussed. This includes an explanation of the differences between the two types of documents used to clear a medical device: (1) premarket notification [510(k)] and (2) premarket approval (PMA) application. Devices intended for "research use only" are also discussed. A computerized cytology device of current interest, the "automated Pap smear reader," is used as an example to further discuss performance and software considerations.     

Optimization of bacteriorhodopsin for bioelectronic devices

Bacteriorhodopsin (BR) is the photoactive proton pump found in the purple membrane of the salt marsh archaeon Halobacterium salinarum. Evolution has optimized this protein for high photochemical efficiency, thermal stability and cyclicity, as the organism must be able to function in a hot, stagnant and resource-limited environment. Photonic materials generated via organic chemistry have yet to surpass the native protein in terms of quantum efficiency or cyclicity. However, the native protein still lacks the overall efficiency necessary for commercial viability and virtually all successful photonic devices using bacteriorhodopsin are based on chemical or genetic variants of the native protein. We show that genetic engineering can provide significant improvement in the device capabilities of proteins and, in the case of bacteriorhodopsin, a 700-fold improvement has been realized in volumetric data storage. We conclude that semi-random mutagenesis and directed evolution will play a prominent role in future efforts in bioelectronic optimization.     

Aptamers as elements of bioelectronic devices

A ferrocene labelled aptamer is used as a redox partner of co-immobilised microperoxidase demonstrating a reversible amperometric biomolecular device that could respond to external stimuli in real time.