G-6-PD as a genetic marker

Biological and NMR markers for cancer

The search for a universal tumor marker continues. Present markers range from tumor products (polyamines, glycoproteins, peptides, hormones or carbohydrate-linked markers) to reaction products produced by the host tissues during tumor invasion. Techniques used to identify them include the classical methods of histology and cytochemistry as well as the more recent radioimmunoassay and metabolic probes. The in vivo techniques of increasing use for patient monitoring are MRS (magnetic resonance spectroscopy) and MRI (magnetic resonance imaging). The efficiency of some markers and statistical methods used in analyzing data are discussed, as are the ethical problems surrounding the use of new testing methods. Recent developments in MRI and MRS, marker elucidation, and evidence for a new autocrine differentiation-inhibiting factor (ADIF) are reviewed. Future needs and approaches focus on greater utilization of indicators of the preneoplastic state and of risk to cancer, as well as more careful attention to statistical analysis.

A sensitive cytochemical staining method for glucose-6-phosphate dehydrogenase activity in individual erythrocytes. I. Optimalization of the staining procedure

A sensitive cytochemical staining method for glucose-6-phosphate dehydrogenase activity in individual human erythrocytes is described. This staining method can be used for the rapid routine discrimination of patients with a deficiency of the enzyme in its homozygote or heterozygote form, but also for quantitative localization of its activity in individual erythrocytes. The staining procedure in its optimal form consists of a treatment of the erythrocytes with sodium nitrite, then a "fixation" in 0.025% glutaraldehyde (under NADP+ protection of the active site of the enzyme), followed by incubation of the cells in suspension in the presence of tetranitro BT, 1-methoxyphenazine methosulphate and polyvinyl alcohol. Using this new technique, a sharp localization is obtained of the glucose-6-phosphate dehydrogenase activity, which enables discrimination between red cells with different levels of enzyme activity, as a consequence of enzyme deficiencies or age changes.