A death attributed solely to diltiazem.

An elderly woman, distraught over the recent death of her husband, was found dead of an apparent suicide. Qualitative screening detected only the presence of diltiazem, an antihypertensive, antianginal agent that was prescribed for a known heart ailment. Quantitation of diltiazem was carried out on available fluids and tissues with the following results: blood 6.7 mg/L, urine 5.4 mg/L, vitreous 5.5 mg/L, and liver 79 mg/kg. Death was subsequently attributed to an overdose of this medication.

Calculation of stable isotope enrichment tracer kinetic procedures.

The choice of method of expressing isotopic enrichment in tracer kinetic experiments utilizing stable isotopes was found to affect the calculation of tracee pool size and half-life. The most commonly used definition, the difference between enriched and natural abundance, i.e. atom percent excess, was found to result in significant error in model systems when the dose of tracer was 10% of the pool size. Errors in determining first-order rate constants of efflux and in pool sizes decreased with decreasing ratio of tracer to tracee. Error in determining pool size increased with longer 'sampling' periods, while error in determining the rate constant increased with shorter sampling periods. Of three less frequently used expressions of isotopic enrichment two were found to yield the exact answers in model systems. The correct expressions of isotopic enrichment were linear functions of the quantity of tracer in the system. A practical example demonstrated the effect of choice of expression of enrichment on estimates of whole body copper pool size and turnover in dairy cattle.