Biomedical subjects
Publications and source records attributed to M Werner.
The courtship activity of male F2 descendants of irradiated and control guppies, Poecilia reticulata, of the inbred strain Istanbul was compared. The results of Spieser and Schröder (1978), who found a decrease in courtship activity of descendants of irradiated guppies, were confirmed under more natural conditions.
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The investigation of the family of a patient with bilateral breast cancer is described. By means of interviews and the checking of hospital records and death certificates, information was obtained on 199 family members over five generations, 19 of whom had cancer. Comparison with expected numbers of cases showed an excess in only one generation. The interpretation of these findings and the advice given to family members are discussed.
Immunoassay of creatine kinase-MB provides numerical information, which makes it possible to estimate quantitatively the diagnostic performance following myocardial infarction. Two graphical methods for such an evaluation are presented. The relationship between technical sensitivity and specificity was analyzed using a continuous function, the receiver-operator characteristic curve. Using this function, a diagnostic threshold ("upper normal limit") was chosen, which balances both technical specificity and sensitivity on the first day following infarction. On the second and third days this threshold caused a progressive loss of technical sensitivity. The relationship between effectiveness and the prevalence of myocardial infarction in the tested population was evaluated with a nomogram correlating these two quantities. With the chosen diagnostic threshold, effectiveness is independent of prevalence on the first day, but the loss in technical sensitivity on subsequent days causes effectiveness to decay when the prevalence is high.
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We have developed an integrated method that overcomes the two main procedural difficulties of gas-liquid chromatography, namely, solvent-solvent extraction and chemical derivatization. Drugs are extracted from serum by column chromatography on granular diatomaceous earth (kieselguhr). Subsequent gas-liquid chromatography of underivatized samples can be performed on either of two liquid phases. A mixed liquid phase, used for quantitative gas-chromatographic assay on patients with a known therapeutic regimen, has enabled quantitation of 12 drugs in serum. Alternatively, a single liquid phase, used with the mixed liquid phase, permits the gas-chromatographic identification of unknown drugs on the basis of the characteristic pattern of the two relative retention times; by this approach more than 40 drugs have been identified in cases of suspected intoxication, both in serum and in gastric aspirate. Besides providing ease of performance and wide applicability, the proposed procedure offers a degree of precision and accuracy that compares favorably with established methods.
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Glucose oxidase, uricase, and urease were immobilized on the interior surface of activated polyamide tubing. The shelf-life of such enzyme bearing tubes was at least six months. The tubes were used for continuous-flow analysis of glucose, uric acid, and urea with conventional systems and with hybrid micro-scale systems in which modules of different manufacture were combined. The length of enzyme-bearing tube required for each system was ascertained empirically. Each tube could be used for several thousand assays, but glucose oxidase-bearing tubes were more stable than urease- or uricase-bearing tubes. Results for patients' samples correlated well with results obtained by accepted methods.
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A Task Force appointed by the College of American Pathologists studied the key elements that may affect a laboratory result, including the types of reagents, manufacturers of detection equipment, blanking procedures, calibrators, diluting and dispensing devices, and sample preparation. A field trial was conducted using cholesterol assay as the pilot study. Participants completed a lengthy questionnaire that requested information regarding the key elements used in the cholesterol assay. This report presents the preliminary findings of the field trial. Examples are shown to illustrate how obtaining additional information about how the laboratory test was performed led to identification of subtle differences in test results.
Depending on the change in magnitude of analytical error occuring with change in concentration of analyte, two limiting types of error properties can be defined: additive and multiplicative. We investigated whether one of these two error types also characterizes the overall error of methods involving multiple procedural steps, or whether mixed error properties result in these cases. Using "open" quality-control data (i.e., and analyst identifies controls) from each of two hospitals and "blind" quality-control data from one hospital for 11 different assays, we found: (a) With current methodology, overall errors typically are mixed, though predominantly additive and multiplicative overall errors exist as well. (b) "Blinding" the quality-control system typically augments the multiplicative but not the additive error component.
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The rosette forming cell (RFC) response of different lymphoid organs (spleen, lymph node, peripheral blood) of guinea pigs was examined by immunocytoadherence. The method has been adapted to work with the soluble antigen BGG. The number of antigen binding cells following immunization with BGG in CFA reached the highest level on day 6 in Ln. popliteus and on the 10th day in spleen and peripheral blood. It is shown that the highest level of antigen binding cells appears generally before the maximum of circulating antibodies. After i.p.-immunization to alum-adsorbed BGG we only detected a small number of RFCs. After pretreatment with 6-mercaptopurineI-25-BGG (MP-BGG) and a control substance (toluylI-25-BGG) over 8 days and in increasing doses we obtained an antigenspecific suppression of BGG binding cells following MP-BGG treatment. In contrast to these findings the antibody titres were only slightly decreased in the beginning of the immune response.
Ultrafiltration of urine and rapidly separates urinary enzymes from inhibitors, activators, and heat-stable, spurious activities present in urine. Using eight enzymes of clinical interest as examples, we verified the reliability of results obtained after ultrafiltration by comparsion with results obtained after gel filtration.
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