Determination of histamine in human plasma: the European external quality control study 1988

There is an increasing interest in measuring human plasma histamine levels in various clinical conditions. A variety of 'old' and newly developed techniques are applied to meet this demand. However, the discrepancy between reported reference values for histamine in human plasma measured using this variety of techniques, suggests the existence of a certain degree of inaccuracy and imprecision. We therefore organized an external quality control study on the reliability of current histamine determinations in European laboratories. Three lyophilized plasma quality control samples, in duplicate, covering the normal and pathological range of histamine concentrations (0-45 nmol/l), two different aqueous histamine standard samples and one solvent sample were sent to 10 laboratories for the analysis of their histamine content. The following methods were used: gas chromatography-mass spectrometry (n = 2), enzymatic single isotopic assay (n = 1), fluorometric-fluoroenzymatic assay (n = 3), radioimmunoassay (n = 3) and high performance liquid chromatography (n = 2). The study was performed and evaluated according to the approved recommendations (1983) of the International Federation of Clinical Chemistry (IFCC). The target values +/- s.d. of the three plasma samples were: 39.5 +/- 4.6 nmol/l (CV = 11.6%), 2.3 +/- 2.2 nmol/l (CV = 96%) and 8.9 +/- 1.5 nmol/l (CV = 17%), respectively.(ABSTRACT TRUNCATED AT 250 WORDS

PERFORMANCE AND PRACTICE: EXAMINING THE MACHINE TOOL INDUSTRIES OF JAPAN AND THE UNITED STATES

Machine tool (MT) production is at the centre of most durable goods manufacturing and is in many ways, an indicator of a country's industrial prowess. Over the past three decades, the machine tool sectors of Japan and the United States have followed distinctly different trajectories. This paper compares and contrasts the performance and characteristics of the MT industries of both countries, with particular attention paid to several embedded differences in each country's manufacturing conditions at various levels. Once the world leader, the US MT industry is in a period of decline, despite signs of a rebound during the 1990s. Japanese MT producers continue to be among the world leaders in terms of both sales and technology, in the face of a recent domestic economic slowdown well over a decade long. The paper concludes with a discussion of the industry's future prospects. Copyright (c) 2006 by the Royal Dutch Geographical Society KNAG.