Trace elements in diabetes mellitus. Peculiarities and clinical validity of determinations in blood cells.

Significantly more information about trace element status can be obtained by investigating concentrations in blood cells instead of only evaluating the concentrations in plasma. This can be explained by the fact that essential trace elements such as zinc, copper, chromium and selenium take part in a variety of enzymatic processes on a molecular cellular level. Ignoring these important biochemical roles, trace element concentrations determined in whole blood or plasma very often lead to conclusions contrary to the actual intracellular concentration.

Serial transplants of DMBA-induced mammary tumors in Fischer rats as a model system for human breast cancer. VI. The role of different forms of tumor-associated stress for the regulation of pineal melatonin secretion.

Previous studies on human breast cancer patients showed a decline in circulating melatonin levels corresponding to primary tumor growth and an increase when relapse occurred. The aim of the current investigation was to study in an experimental model possible mechanisms involved. Inbred female F344 Fischer rats were used for serial passages derived from a chemically induced mammary adenocarcinoma.

Concepts for a model of good medical laboratory services.

Several international standards and corresponding interpretation documents for quality management systems have been published. Although these standards are found useful to some extent, they are considered to be insufficient in several areas important for medical laboratories particularly in the pre- and post-examinational phases. The normative document for accreditation of laboratories (ISO/IEC Guide 25) is presently being revised and a document for medical laboratories (ISO/TC 212, CD 15189) is at draft stage.