Biomedical subjects
Publications and source records attributed to D McCulloch.
A 52-year-old black male with Duane's retraction syndrome and fundus pigmentation was examined. The patient had high hyperopia and reported ocular problems in other family members. A battery of tests indicated that the pigmentary anomalies were not due to retinitis pigmentosa.
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A nonperturbing technique of thin-layer liquid crystal thermometry was developed to quantitate heating of Chinese hamster ovary cells and the bacterium Serratia marcescens when exposed to 2450-MHz microwave fields at 0.2-0.5 W/cm2. Cells suspended in culture medium were injected into 5-cm glass microcapillary tubes coated on the inside with a thin layer of liquid crystal. The tubes were sealed and placed parallel to the electric field in a watertight waveguide exposure chamber where they were heated by circulating temperature-controlled water. Even at high circulation rates, liquid crystal color changes indicated local microwave capillary tube heating of 0.1-0.25 degrees C. Precision of measurement was 0.02 degrees C. Observations during microwave heating were significantly different from observations without microwaves at the 1% level, and heating increased as circulating water flow was reduced from 300 ml/s to 100 ml/s. The results of a cell survival assay following hyperthermal treatment were in good agreement with expectations based on the observations of microwave heating using liquid crystals.
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Studies were conducted on the free-field heating of mammary tumors on the flank of mice and of tissue equivalent phantoms. A 200 watt, P.M., 2450 MHZ source was marginal in heating 1 cm tumors from room ambient to 38 degrees C. A technique was developed using warm air to raise the thermal baseline of the tumors to body core temperature and microwaves to produce significant hyperthermal levels. This allowed the production tumor temperatures of 45 degrees with greatly reduced microwave power and with significantly more uniform temperatures. However, the non-uniformity in temperature achieved with monodirectional microwave heating is still considered to be excessive: +/- 1 degrees C.
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Increases in expenditure on medicines above the level of increases in health care are generally, a feature of all Western health systems. From the early 1990's, the average annual growth rate (AAGR) in pharmaceutical expenditure exceeded the AAGR in health among all the European member states 1. In Ireland, the expenditure on drugs, as a percentage of health care spending, was 7.1% in 1987 compared with 9.2% in 1997. The state expenditure on medicines increased from 165.8 million Pounds in 1993 to 278 million Pounds in 1998 representing an average increase of 11% each year. All the available evidence indicates that the expenditure on medicines will continue to show real growth, and take an increasing share of the total health care budget. Analysis shows that the main reasons driving such growth include those of "product mix"--the prescribing of newer, more expensive medicines, in addition to the 'volume effect' comprising growth in the number of tablets per prescription. These two factors account for 80% of the observed increase in drug cost 2. Six therapeutic classes accounted for 16 of the top 20 most expensive drugs prescribed under the GMS in 1998 3. These areas can be classified as follows: peptic ulcer disease, asthma, hypertension/cardiac failure, antidepressants, anti inflammatory and lipid lowering drugs. In this article we discuss the clinical evidence base, and the pharmacoeconomic implications of lipid lowering therapy in this country.