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Biomedical subjects

J O Hoeke

Publications and source records attributed to J O Hoeke.

12 recordsLinked to original sources
PubMed2000

Evaluation of techniques for the presentation of laboratory data: support of pattern recognition.

Two tabular and two graphical techniques for the presentation of laboratory test results were compared in a reaction-time experiment with 22 volunteers. The experimental setup was designed to determine whether one or more of the presentation techniques facilitated the recognition of four predefined combinations of abnormal test results. Using a conventional, tabular presentation technique as a reference, faster median response times were obtained with each of the other three presentation techniques, irrespective of pattern. The effect on accuracy was less clear, possibly due to the small number of errors made.

Clinical Laboratory Information Systems↗
PubMed1997

Evaluation of techniques for the presentation of laboratory data. I: Time needed for interpretation.

Four tabular and two graphical techniques for the presentation of laboratory test results were evaluated in a reaction-time experiment with 25 volunteers. Artificial variables and values were used to represent sets of 12 laboratory tests to eliminate the possible effects of clinical experience. Analyses focused on reaction times for correctly classified sets of data. For comparable data sets, Presentation Techniques (PT) that use color, always allow faster interpretation than PTs that do not use color, or use only a simple marker. Color-coded tables yielded an improvement in median reaction time of approximately six times or better, as compared to the reference PT (a tabular PT without any hints). For the color-coded graphs, the improvement rate was approximately 2.5 or better.

Clinical Laboratory Techniques↗
PubMed1997

Evaluation of techniques for the presentation of laboratory data. II: Accuracy of interpretation.

Four tabular and two graphical techniques for the presentation of laboratory test results were evaluated in a reaction time experiment with 25 volunteers. Artificial variables and values were used to represent sets of 12 laboratory tests to eliminate the possible effects of clinical experience. Analyses focused on four types of errors in interpretation. Color-coded tables and one of the color-coded graphs greatly (2.8 times or better) reduced the number of incorrectly classified test results, as compared to the reference presentation technique. This was mainly due to a reduction of the number of abnormal test results that were not noticed by the subjects when using these presentation techniques.

Clinical Laboratory Techniques↗
PubMed1991

Graphical non-linear representation of multi-dimensional laboratory measurements in their clinical context.

A polygon-based graphical representation of laboratory test results using nonlinear scaling is described. It is argued that the nonlinearity of the scale and the use of colors in the representation facilitates interpretation of the test result in its relationship to the standard reference range and critical clinical decision levels. Preliminary results suggest that this representation may be fruitfully used to enhance the efficiency of the information transfer from the clinical chemistry laboratory to clinicians. Other applications, inside as well as outside the medical field, may easily be imagined.

Chemistry, Clinical↗
PubMed1987

A three-parameter Langmuir-type model for fitting standard curves of sandwich enzyme immunoassays with special attention to the alpha-fetoprotein assay.

In a simplified approach to the reaction kinetics of enzyme-linked immunoassays, a Langmuir-type equation y = [ax/(b + x)] + c was derived. This model proved to be superior to logit-log and semilog models in the curve-fitting of standard curves. An assay for alpha-fetoprotein developed in our laboratory with a sensitivity of 2 g/liter and a between-day coefficient of variation of about 15% was used for comparison of the different models. The proposed model has the advantage that it is based on the law of mass action and that blank determinations can be included in the calculation of the curves without giving a disproportionate bias.

Enzyme-Linked Immunosorbent Assay↗
PubMed1985

Comparison of three different assay procedures for the determination of HbA1 with special attention to the influence of pre-HbA1c, temperature and haemoglobin concentration.

Three different methods for the measurement of glycated haemoglobin or HbA1, based on agar gel electrophoresis, ion-exchange and affinity chromatography were compared. All three showed acceptable precision (overall CV being less than 5%) and correlated well with each other (r greater than 0.945). The ion-exchange and affinity chromatography method proved to be independent of the amount of pre-HbA1c present. The electrophoresis method was independent of temperature in contrast to the other two methods, which showed a strong and comparable temperature dependency. All three methods were dependent on the haemoglobin concentration and/or protein content of the haemolysate. Both ion-exchange and electrophoresis showed significant interference by changes in haemoglobin concentrations, whereas the protein concentration significantly biased the affinity chromatography figures. Taking into account their specific merits all three methods are acceptable for routine use.

Chromatography, Affinity↗
PubMed1983

Effects of furosemide on biliary secretion, pancreatic blood flow, and pancreatic exocrine secretion.

The effects of furosemide on biliary secretion and on pancreatic hemodynamics and exocrine function were studied by quantitative flowmetry and timed collections of biliary and pancreatic exocrine secretion in the anesthetized dog. Biliary flow and the output of its components (Na+, K+, Ca, Mg, 3-OH bile salts, and bilirubin) increased significantly following a furosemide injection of 0.6 mg/kg and rose progressively to 75-150 per cent above basal levels as the furosemide dose was increased to 9.6 mg/kg. Pretreatment with secretin had no influence on furosemide-induced biliary secretion. Furosemide doses of 4.8 and 9.6 mg/kg increased blood flow in the superior pancreaticoduodenal arterial bed by 30-60 per cent but did not alter flow in the inferior pancreaticoduodenal arterial bed or the pancreatic branch of the splenic artery. However, small increases were seen in flow in the latter two arterial beds after furosemide when secretin administration preceded furosemide. Basal pancreatic secretion was not affected by furosemide, but pretreatment with a submaximal sustaining infusion of secretin uncovered a furosemide action to increase pancreatic exocrine flow and the outputs of Na+, K+, Ca, Mg, and enzymes by 25-35 per cent. These data extend previous studies of the gastrointestinal vasodilator effects of furosemide to the pancreatic circulation and previous data demonstrating furosemide-induced ionic transport in nonrenal systems to biliary, pancreatic acinar, and ductular transport in both organs. Whether the augmentation of pancreatic blood flow is secondary to enhanced ion transport in the exocrine pancreas or to an effect on ionic cotransport in vascular smooth muscle is unknown.

Animals↗