Postmortem Liver Samples Research Articles

Microassay of tyrosine-amino transferase and p-hydroxyphenylpyruvic acid oxidase in mammalian liver and patients with hereditary tyrosinemia

An enzymatic microassay method for tyrosine aminotransferase and p-hydroxyphenylpyruvic acid oxidase is described which can detect as low as 0.25 μmoles of tyrosine metabolized per hour per gram wet weight of liver and 0.125 μmoles of p-hydroxyphenylpyruvic acid metabolized per hour per gram wet weight of liver. The assay is applicable to 0.5 mg wet weight of liver sample. In addition, stability studies with liver tissue under various conditions of preservation are given. Comparative studies are presented dealing with tyrosine aminotransferase and p-hydroxyphenylpyruvic acid oxidase activities obtained under macro- and microassay conditions in guinea pig and human liver specimens. Properties of tyrosine aminotransferase and p-hydroxyphenylpyruvic acid oxidase such as temperature coefficient and apparent Michaelis-Menten affinity constants in guinea pig and human liver have been determined. Tyrosine aminotransferase and p-hydroxyphenylpyruvic acid oxidase activities in two postmortem liver samples from patients with “hereditary tyrosinemia” have been determined using microassay conditions.

The Identification and Removal of Certain Interfering Substances Encountered in the Determination of Barbiturates in Human Liver

The identification of barbiturates in post-mortem liver samples is sometimes subject to interference. The cause of this has been investigated and a number of the interfering substances have been characterized. Modified procedures are proposed for use when appropriate to prevent this interference.