Clinical and Physiological Investigations

For some substances, information on some toxicological endpoints is available from clinical and physiological investigations such as provocation tests for detecting allergy, lung function tests, and analyses of biochemical parameters and biomarkers for exposure or effects. 

From such investigations, the exposure concentration or dose is often unknown and thus, a dose-effect relationship is difficult to evaluate. Therefore, information from clinical and physiological investigations generally has a limited use in the hazard assessment exceptions are identification of skin sensitizers and indications of possible adverse effects to selected organs and tissues depending on the investigations performed. 

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The wealth of reports in the literature describing the use of BSP and other dyes is testimony to the value of dye tests in clinical and physiological investigations. Comparative studies in clinical situations have shown that dye tests are almost invariably more sensitive to liver damage than are other biochemical tests and that there is good eorrelation between the results of dye tests and histological findings in patients who have minimal clinical evidence of liver dysfunction. 

In principle, activation analysis allows the opportunity of distinguishing between different isotopes of an element. This facility has been usefully exploited in a number of clinical and physiological investigations. 

Increased numbers, particularly of neutrophils, characterize many inflammatory states. This is a physiologically appropriate response and no treatment is necessary. Conversely, there may be elevations due to underlying haematological malignancies or seen in acute or chronic leukaemia. Once such a suspicion arises the patient should immediately be referred to a clinical haematologist. Specialist investigation and management falls outside the ambit of this chapter. 

Calorimetric measurements of heat dissipation by animal tissue and cells have a firm foundation in the rigorous Laws of Thermodynamics. In essence, the metabolic activity of the material is being measured and detection of alterations to this activity in physiological, clinical, and pathological conditions could become a valuable addition to our medical armory. But calorimetiy can also be a deeper probe to investigate human diseases, by combining it with conventional biochemical assays to ensure that account is made of all pathways in the metabolism of normal cells and those in a diseased state with altered metabolism—the enthalpy balance method. Above all, confidence in understanding the Laws of Thermodynamics enables us, as perennial students, to more clearly appreciate the Laws of Nature which all obey. 

The two purposes of separation of amino-acid and peptide mixtures are either at the preparative level, to isolate one or more individual components from the mixture for further study or at the analytical level, to identify and to determine the relative amounts of some or all of the components. Most of the routine studies, conducted daily to determine the amino-acid content of clinical and botanical samples in hundreds of laboratories around the world, are at the analytical level. However, many of the research studies are at the preparative level an example of this is the identification of crosslinking amino acids from proteins, through their isolation from protein hydrolysates, from physiological specimens for medical investigations, or purely to gain new knowledge. 

G. Fontani, et al., Cognitive and Physiological Effects of Omega-3 Polyunsaturated Fatty Acid Supplementation in Healthy Subjects, European Journal of Clinical Investigation 35 (2005) 691-699. 

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