Human factors in the design of medical devices - Approaches to meeting international standards in the European Union and USA.

This paper focuses on the challenges of meeting agency requirements as it pertains to the application of human factors in the medical device development (MDD) process. Individual case studies of the design and development process for 18 medical device manufacturers located in the US and EU were analyzed and compared using a multiple case study design. The results indicate that there are four main challenges in implementing international standards.

A coaxial single fibre supercapacitor for energy storage.

An energy storage device--a coaxial single fibre supercapacitor--was developed using a dip coating method and characterised using electrochemical methods. The specific capacitance per unit area and length were calculated to be 3.18 mF cm(-2) and 0.

Entry of mouse embryonic germ cells into meiosis.

Germ cells harvested from mouse embryonic genital ridges were mixed with disaggregated embryonic lung cells, and the reaggregates were cultured for 4-7 days. Germ cells derived from female embryos 10.5-13.

Fowlpox virus: pathogenicity and vaccination of day-old chickens via the aerosol route.

Day-old chickens were given a single fowlpox virus vaccination (strain HP201) either via the aerosol or wing-web route. Both methods induced protective immunity against a wing-web or intravenous challenge with virulent fowlpox virus at 47 days old, although high titred virus preparations were required for successful aerosol vaccination. However, no clinical signs of infection were observed as a result of aerosol vaccination even if invasive strains of Escherichia coli were administered simultaneously.

Fowlpox vaccination: routes of inoculation and pathological effects.

Chickens were vaccinated against fowlpox via the wing web, oral route, drinking water or by aerosol. Using two inoculations of virus, at 5 and 26 days of age, protective immunity was induced in chickens which resisted challenge with a pathogenic fowlpox virus given either via the wing web or intravenously at 46 days of age. Aerosol and wing web vaccination induced slightly better protective immunity than drinking water or oral vaccination.

Demonstration of antibodies to turkey rhinotracheitis virus in serum from commercially reared flocks of chickens.

Using both an ELISA and a serum neutralisation test, antibodies to turkey rhinotracheitis (TRT) virus were found in sera collected from commercial flocks of chickens after the initial appearance of TRT in turkeys in Britain in mid-1985 but not in chicken sera collected before that time. Good correlation was found between the results of the two assays and antibodies were found in chickens of all commercial types and of all ages, ranging from 31 days to 56 weeks. Apparently healthy flocks appeared to have been infected with the virus, as did flocks which had recovered from a variety of disease outbreaks including ones attributed to infectious bronchitis, and severe tracheitis as well as swollen head syndrome.

Fowlpox virus: its structural proteins and immunogens and the detection of viral-specific antibodies by ELISA.

This study showed a possible 30 structural polypeptides in the fowlpox virion. There were three major structural proteins, of relative molecular mass (rmm) 91, 64, and 58 kDa which were not major immunogens. Although most viral polypeptides were shown to be immunogenic, antibodies in chicken sera taken after a primary fowlpox inoculation reacted strongly only with polypeptides of 37 and 35 kDa, whereas antibodies in sera taken after a secondary inoculation also reacted strongly with six other viral structural polypeptides.