Clinical biochemistry
-
An approach to acid-base physiology based on quantitative relationships between systems is presented. Key elements in the approach advocated by Stewart are, first, that changes in H+ or protons and bicarbonate are not considered "primary," or initiating disturbances, but rather as changes that are "dependent" on the interactions between several systems. ⋯ In plasma, the systems and variables are strong ions (strong ion difference, SID); weak acids, or buffers (ion equivalence of total protein concentration, AtOt); and carbon dioxide (PCO2, as influenced by alveolar ventilation). This system provides a quantitative description of the interplay between systems, and it makes it much simpler to understand the effects of ion movements between cells and plasma, renal control of acid-base, the influence of metabolism, and management of acid-base disorders.
-
Clinical biochemistry · Oct 1977
Clinical usefulness of alkaline phosphatase isoenzyme determinations.
1. We report on the clinical usefulness of alkaline phosphatase isoenzyme determinations using a combined chemical inhibition method on 731 patient serum specimens exhibiting elevated (greater than 350 U/L) alkaline phosphatase (AP) activity. 2. The relative percentages of the organ-specific alkaline phosphatase activities were computed on the basis of three independent assays: total activity, activity in the presence of 10 mMl-phenylalanine, and activity in the presence of 3.1 M urea. 3. ⋯ Using an upper reference limit of 30 U/L for GGT and comparing the GGT results with the percent liver AP, we found that the GGT results were 91% sensitive and 60% specific. 4. We conclude that AP isoenzyme determinations are very useful in identifying the organ source(s) responsible for elevated AP values. 5. The reference ranges for several age groups in relation to the adult population and their significance are presented.
-
Clinical biochemistry · Oct 1976
The use of gamma-glutamyl transpeptidase in differentiating liver from bone isoenzymes of alkaline phosphatase.
Sixty-one patients with elevated alkaline phosphatase activity due to liver or bone diseases were studied. An attempt was made to identify the origin of the increased alkaline phosphatase by chemical inhibition, by inactivation by heat and urea, and by electrophoretic separation. The results obtained from these procedures were correlated with the gamma-glutamyl transpeptidase activities performed on each patient. We concluded from this study that gamma-glutamyl transpeptidase determination, together with alkaline phosphatase electrophoretic separations, are useful laboratory procedures for accurately identifying the origin of elevated alkaline phosphatase activity.