Hamilton Smith

The Distribution of Antimony, Arsenic, Copper and Zinc in Human Tissue

Introduction In dealing with problems of forensic science, public health or general medical research, where the level of trace elements in tissue is important, one of the basic requirements is a set of normal concentrations. These are often not available, or are expressed as less than the limit of detection, or vary widely from source to source. The technique of activation analysis (Bowen and Gibbons, 1963, Smith and Lenihan, 1964) has for the first time made it possible accurately to analyse a complete range of normal tissue samples. Though y-spectrometry can be used it is possible to make this analyses by simple techniques, involving some chemistry, in an ordinary chemical laboratory. Moreover, the samples may be analysed with surprising rapidity and no loss of accuracy. As an example, the values quoted in the following survey were dealt with a t a rate of 40-50 per day excluding sample preparation, weighing and irradiation. As a further point of interest it should be noted that all the samples in the survey were irradiated at a distance of 400 miles from the laboratory in which they were processed.

The relation between primidone and phenobarbitone blood levels

A dose of primidone or one fifth of the same weight of phenobarbitone produced equal levels of phenobarbitone in the blood.

Mercury in Human Tissue

Mercury has been known to be highly toxic for a very long time. To-day, though industrial exposure is relatively controlled, there are still many reports of poisoning by mercury. In general these are due to thoughtlessness or carelessness rather than mismanagement or ignorance. Most trained personnel have been told repeatedly that mercury has a significant vapour pressure at room temperature (0.001 mm at 18°C) and much higher when exposed to slightly higher temperatures (0.27 mm at 100°C) and is, therefore, a health hazard. The following work describes a few incidents caused by the misuse of mercury and illustrates just how insidious a health hazard it can be. In dealing with problems of forensic science or public health where the level of trace elements in tissue is important, one of the basic requirements is a set of normal concentrations. These are often not available or expressed as less than the limit of detection or varying widely from source to source. Using the technique of activation analysis it is possible easily to analyse a range of normal tissue samples as required. This was done for the mercury investigations, and the results are given below for over twenty tissues.

Sodium Chlorate Poisoning

Two cases of suicidal poisoning by sodium chlorate are reported. Results obtained by toxicological, microscopical and macroscopical investigations are given, and a limited study of the stability of chlorate in the presence of tissue is described.

The Interference of Putrefactive Bases in the Analysis of Biological Materials for Drugs

A study has been made of a group of compounds known as putrefactive bases. Data has been collected for them using thin-layer chromatography, colour reactions on the silica gel layer, gas-liquid chromatography and ultraviolet spectrography. The results have been used to interpret the analysis of both blood samples stored at room temperature for several months and of cases of medicolegal interest where considerable delay has occurred before death has been discovered. It was found that β -phenylethylamine was the most frequently encountered putrefactive base. However, it was impossible either to determine the degree to which it occurs with time or predict any pattern of occurrence for the other compounds.

The determination of selenium in biological material by thermal neutron activation analysis and atomic absorption spectrometry

Neutron activation analysis and atomic absorption spectrometry (graphite furnace) methods for the analysis of selenium in human tissue are described. The sensitivity (10–30 ng/sample), accuracy and precision are of the same order for both techniques and the choice can only be made on grounds of urgency or convenience. AAS should be chosen for the analysis of wet tissue or the urgent analysis of small numbers of dry tissue. NAA should be chosen for the analysis of large numbers of dry tissue samples where time is not important. The selenium concentration of human liver is shown to be in the region of 1 to 2 ppm (dry weight). Selenium may be lost from tissue during freeze drying if the samples are not maintained at −35°C.

Poisoning by strychnine.

Four cases of strychnine poisoning are presented and compared with 5 cases from other sources. High levels of strychnine in the liver may result in death without evidence of physical struggle. Low levels suggest a delayed death probably accompanied by the physical responses commonly attributed to strychnine poisoning. In the 3 suicides described, the strychnine was obtained from farming sources.

The Detection of Barbiturates and Related Drugs by Thin Layer Chromatography

Summary This paper describes a method for the detection and identification of barbiturates and a few related compounds. The whole process can be completed in thirty to forty minutes and is a valuable aid in situations where the rapid identification of barbiturates is important, e.g. pre-race testing of racing animals. Detection without identification may be completed within fifteen minutes. (Readers are also referred to an interesting paper on Barbiturate Detection Using Thin Layer Chromatography by Sunshine et al. in Clinical Chemistry, 1963, 9, 312. Ed.)

INDUSTRIAL EXPOSURE TO ARSENIC

The normal levels of arsenic in human tissue are reported together with the arsenic concentrations found in the investigation of a large number of industrial exposure incidents. These results are useful for establishing that industrial exposure has taken place and for confirming arsenic poisoning but they cannot be used realistically to predict that any person or group will suffer a visible deterioration in health because no correlation between arsenic contamination and symptoms can be made. Industrial workers who are affected by arsenic exposure are often no more exposed than their co-workers.

The detection, identification and measurement of indole, tryptamine and 2-phenethylamine in putrefying human tissue

Indole, tryptamine and 2-phenethylamine are putrefactive products which may be found in decaying human tissue. They may be identified by the data given found in decaying human tissue. They may be identified by the data given for infrared and ultraviolet spectrometry, fluorometry, thin layer and gas chromatography and mass spectrometry. Quantitative studies may be made using the gas chromatography method described. The rate of formation is affected by temperature and preservatives and may be prevented if necessary by the use of sodium fluoride. No relationship between the production of these materials (and alcohol) and time since the post-mortem examination could be established. The post-mortem examinations took place within 24 hours of death.