Biomedical subjects
Publications and source records attributed to P Hagemann.
In the context of total quality management the paper is focused on analytical quality with special emphasis on the preanalytical steps from the patient to the sample. At the present time those are the most important limiting factors of the quality of laboratory results.
The area of pre-analysis, from the indication for a test to the analytical instrument, represents the interface between the physician requesting laboratory tests and the analyst performing them. Given the high standard of current analytical practice, this area has become limiting with regard to the usefulness of laboratory medicine. Pertinent problems are illustrated by means of several examples. Hints on avoiding this kind of error are given.
Preanalytical influence factors are of paramount significance for the quality of a laboratory result. As a rule, their importance is greater than the inadequacies of the analytical process. Examples from the physician's laboratory concerning adult patients and primary samples are discussed. Weak points can be a lack of professionalism in the personnel involved as well as the need to send out and transport samples. The strong point of the office laboratory is its orientation towards a specific patient.
We describe the construction, the reaction principle and the performance of Reflotron K+, a new Reflotron test for the quantitative determination of potassium in serum and heparinized plasma. The reaction principle is based on the introduction of the potassium cation via valinomycin into a non-polar phase; the accompanying loss of protons from the non-polar phase is detected by the colour change of a pH indicator. The multicentre evaluation of the reagent carrier system showed in median CVs of < 0.9% (within-series in heparinized plasmas) and 1.3% (run-to-run in control sera). The recovery in control sera was +/- 4% for seven laboratories. In the method comparison with flame emission spectrometry, using sera and heparinized plasma samples, regression analysis yielded correlations with slopes of 1.00 +/- 0.04 (median slope 1.005) and negligible intercepts. The reagent carrier system showed a linear response in the measuring range 2-12 mmol/l. Bilirubin (up to 513 mumol/l), triacylglycerols (up to 5,7 mmol/l), sodium (135-189 mmol/l) and ammonium ions (up to 590 mumol/l) did not interfere with the test. Comparison with the results from flame atomic emission spectrometry shows that the recoveries of Reflotron K+ and the direct potentiometric method are slightly and similarly influenced by total protein. With a panel of 28 drugs tested, no interference could be detected. Reflotron K+ provides a precise and reliable procedure for the measurement of potassium in serum and heparinized plasma.
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We present an analysis of the clinical significance of creatinine concentrations less than or equal to 4 mg/L (35 mumol/L) in serum as measured by a specific enzymatic method. In an unselected hospital patient population, 4% of whom had serum creatinine concentrations this low, a value of 5 mg/L (44 mumol/L) or higher was obtained on repeat analysis for a third of these patients, but the remaining two-thirds had persistently low values. Associated clinical conditions included low body mass, pregnancy, insulin-dependent diabetes mellitus, and total immobilization, but 12% of the patients, all female, had no obvious cause for the persistently low creatinine concentration. We conclude that low concentrations of creatinine in serum have no profound clinical significance.
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Sera from 17,166 blood donors living in 10 cantons of northern Switzerland in an area endemic for Echinococcus multilocularis were investigated by serological survey for alveolar echinococcosis (AE). A highly species-specific antigen (Em2) and a commonly used E. granulosus hydatid fluid antigen (EgHF) were compared for their suitability in seroepidemiology. EgHF showed a degree of nonspecificity which did not allow direct detection of AE cases. Antibody reaction with Em2 resulted in the detection of 2 asymptomatic clinical cases of AE (seroprevalence 0.01%) within this population of blood donors. A further 4 persons were positive in Em2-ELISA. These 4 persons had negative imaging studies and will be followed serologically and clinically.
The attempt is made to demonstrate that the cerebral systems susceptible to affection in endogenous psychoses arose early in the stage of human development, and are thus of social origin. The biological aspects (inheritability, structures, metabolism) and the social aspects of these affections both arise out of the same human characteristics that distinguish man from animals. It thus seems within the bounds of possibility to resolve the fundamental inconsistency in the theory of endogenous psychoses.
The capabilities of modern computerized X-ray analysis systems can be expanded to the acquisition of various signals available in the electron probe microanalyzer, in parallel with the X-rays. These facilities allow the use of backscattered electrons for the measurement of the total specimen mass thickness, which can be used in mass fraction calculations, up to a (biological) specimen thickness of 10 micron. A mass measurement procedure based on the use of backscattered electrons may become an alternative for the X-ray continuum normalization method, often used in electron probe X-ray microanalysis. A mass measurement procedure using backscattered electrons is described, and preliminary results are given.
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Departing from a short description of the development of psychiatry in the GDR and the assessment of the present care situation, principles and targets of the further development are outlined on the basis of the result obtained by a research group "Organisation of Psychiatric Care". In the foreground there are the principles of vicinity of the community (decentralisation), the formation of function units of inpatients, semiclinical and outpatient treatment establishments (including the offer of care at sheltered work places, lodgings and during leisure time) for surveyable territories (sectorisation) and the integration of psychiatry in medicine and society.
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