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Papers by Helma Kaptein

Research paper thumbnail of Lectorenplatform Applied Science (NL)

Research paper thumbnail of Early detection of acute myocardial infarction with the new marker Fatty Acid-Binding Protein : rapid testing and diagnostic value

There are several requirements for the early detection of AMI with biochemical markers: The bioch... more There are several requirements for the early detection of AMI with biochemical markers: The biochemical marker should be: - Specific - Sensitive - Fast elevated after the clinical onset of the symptoms. The test should be: - Easy to perform - Give a fast result - Preferably bedside - Inexpensive Here, we demonstrate the biochemical characteristics of heart-type Fatty Acid-Binding Protein (FABP) in AMI and UAP patients. Also, we show some preliminary data on a new in-house made quantitative rapid test with simple test procedures. - Patients: 50 patients of the CCU of PWH are included in the study diagnosed with UAP or AMI. Eight blood samples per patient were taken at 0-72 hours after admission and analyzed with a laboratory ELISA test. - Rapid test procedure: 80 ml plasma or serum is added on the sample pad. Within 5 minutes, the strip can be read out with an optical reader (the PART from LRE, Munich, Germany). A release curve for AMI patients shows a significantly elevated FABP con...

Research paper thumbnail of Ultrafiltration as an alternative for microdialysis

Research paper thumbnail of Affinitätsassay zur schnellen Untersuchung biologischer Materialien

Research paper thumbnail of Test strips for the assay of biological materials, for clinical diagnosis etc. carry affinity molecules and can take or support a flow to give time-related reactions

Research paper thumbnail of Development of sampling and bioselective techniques for on-line clinical biosensors

Research paper thumbnail of Novel immunosensors for rapid diagnosis of acute myocardial infarction

Advances in Biosensors, 1999

Research paper thumbnail of Analysis of cortisol with a flow displacement immunoassay

Sensors and Actuators B: Chemical, 1997

This study investigates a flow immunoassay for cortisol based on displacement of labelled antigen... more This study investigates a flow immunoassay for cortisol based on displacement of labelled antigen analogues from immobilised antibodies. On a displacement column, two antibodies with different affinities were immobilised on protein-A Sepharose, and a construct of cortisol and horseradish peroxidase (cort-HRP) was associated to the antibodies. Perfusion of the column with cortisol displaced a proportional amount of cort-HRP. On-line detection was performed with an electrochemical detector measuring cort-HRP directly in a flow injection system. For investigating some characteristics of the displacement system, cort-HRP was also detected off-line, with a substrate for HRP, which changes OD 492. We tested our system in buffer as well in serum for 2 days at a flow of 4-6 ml min − 1. Analysis of the data show a detectable displacement signal at physiological cortisol concentrations. The specificity, stability of the columns and the influence of the antibody affinity were studied.

Research paper thumbnail of The Responses of Fatty Acid-Binding Protein and Creatine Kinase to Acute and Chronic Exercise in Junior Rowers

Research Quarterly for Exercise and Sport, 2003

The responses of fatty acid-binding protein (FABP) and creatine kinase (CK) were compared in a gr... more The responses of fatty acid-binding protein (FABP) and creatine kinase (CK) were compared in a group of junior rowers during 5 weeks of training. Acute exercise induced a larger increase in FABP (70-362%) than in CK (24-156%). When the chronic effect of exercise was studied, the baseline FABP levels were independent of previous training. However, the baseline CK level was dependent on the training that took place during 1 day before (F = 4.362, p < .01) and on the combined training on the previous 2 days (F = 4.606, p < .005). The present results suggest that FABP and CK could be used to monitor acute exercise and chronic exercise, respectively.

Research paper thumbnail of On-line flow displacement immunoassay for fatty acid-binding protein

Journal of Immunological Methods, 1998

In standard displacement flow immunoassays the analyte in the sample creates an active dissociati... more In standard displacement flow immunoassays the analyte in the sample creates an active dissociation of labelled antigens Ž. or antigen homologues from an antigen binding site of an immobilized antibody, after which the labelled substance is measured downstream. Such systems have been described for molecules up to 1 kDa. In this study, we demonstrate Ž displacement in a flow system for the detection of a small protein, cytoplasmic heart-type fatty acid-binding protein 15. kDa , a plasma marker for myocardial injury. The displacement system uses an inverse setup: enzyme labelled monoclonal antibodies are associated to immobilized antigen, and are displaced by analyte in the sample. The system permits detection Ž y1. Ž y1. of both physiological 2-12 mg l and pathological concentrations 12-2000 mg l of fatty acid-binding protein in an on-line flow system.

Research paper thumbnail of Continuous Lactate Measurement that Combines a Portable Ultrafiltration Storage Device with an Enzyme Sensor

Analytical Letters, 2000

The total weight of the collection system is only 8g, allowing free movement of the person being ... more The total weight of the collection system is only 8g, allowing free movement of the person being tested.

Research paper thumbnail of Continuous Ultraslow Microdialysis and Ultrafiltration for Subcutaneous Sampling As Demonstrated by Glucose and Lactate Measurements in Rats

Analytical Chemistry, 1998

Research paper thumbnail of Slow ultrafiltration for continuous in vivo sampling: application for glucose and lactate in man

Analytica Chimica Acta, 1999

Research paper thumbnail of Methodological aspects of glucose monitoring with a slow continuous subcutaneous and intravenous ultrafiltration system in rats

Biosensors and Bioelectronics, 1997

Research paper thumbnail of Early detection of acute myocardial infarction with the new marker Fatty Acid-Binding Protein : rapid testing and diagnostic value

Research paper thumbnail of Lectorenplatform Applied Science (NL)

Research paper thumbnail of Early detection of acute myocardial infarction with the new marker Fatty Acid-Binding Protein : rapid testing and diagnostic value

There are several requirements for the early detection of AMI with biochemical markers: The bioch... more There are several requirements for the early detection of AMI with biochemical markers: The biochemical marker should be: - Specific - Sensitive - Fast elevated after the clinical onset of the symptoms. The test should be: - Easy to perform - Give a fast result - Preferably bedside - Inexpensive Here, we demonstrate the biochemical characteristics of heart-type Fatty Acid-Binding Protein (FABP) in AMI and UAP patients. Also, we show some preliminary data on a new in-house made quantitative rapid test with simple test procedures. - Patients: 50 patients of the CCU of PWH are included in the study diagnosed with UAP or AMI. Eight blood samples per patient were taken at 0-72 hours after admission and analyzed with a laboratory ELISA test. - Rapid test procedure: 80 ml plasma or serum is added on the sample pad. Within 5 minutes, the strip can be read out with an optical reader (the PART from LRE, Munich, Germany). A release curve for AMI patients shows a significantly elevated FABP con...

Research paper thumbnail of Ultrafiltration as an alternative for microdialysis

Research paper thumbnail of Affinitätsassay zur schnellen Untersuchung biologischer Materialien

Research paper thumbnail of Test strips for the assay of biological materials, for clinical diagnosis etc. carry affinity molecules and can take or support a flow to give time-related reactions

Research paper thumbnail of Development of sampling and bioselective techniques for on-line clinical biosensors

Research paper thumbnail of Novel immunosensors for rapid diagnosis of acute myocardial infarction

Advances in Biosensors, 1999

Research paper thumbnail of Analysis of cortisol with a flow displacement immunoassay

Sensors and Actuators B: Chemical, 1997

This study investigates a flow immunoassay for cortisol based on displacement of labelled antigen... more This study investigates a flow immunoassay for cortisol based on displacement of labelled antigen analogues from immobilised antibodies. On a displacement column, two antibodies with different affinities were immobilised on protein-A Sepharose, and a construct of cortisol and horseradish peroxidase (cort-HRP) was associated to the antibodies. Perfusion of the column with cortisol displaced a proportional amount of cort-HRP. On-line detection was performed with an electrochemical detector measuring cort-HRP directly in a flow injection system. For investigating some characteristics of the displacement system, cort-HRP was also detected off-line, with a substrate for HRP, which changes OD 492. We tested our system in buffer as well in serum for 2 days at a flow of 4-6 ml min − 1. Analysis of the data show a detectable displacement signal at physiological cortisol concentrations. The specificity, stability of the columns and the influence of the antibody affinity were studied.

Research paper thumbnail of The Responses of Fatty Acid-Binding Protein and Creatine Kinase to Acute and Chronic Exercise in Junior Rowers

Research Quarterly for Exercise and Sport, 2003

The responses of fatty acid-binding protein (FABP) and creatine kinase (CK) were compared in a gr... more The responses of fatty acid-binding protein (FABP) and creatine kinase (CK) were compared in a group of junior rowers during 5 weeks of training. Acute exercise induced a larger increase in FABP (70-362%) than in CK (24-156%). When the chronic effect of exercise was studied, the baseline FABP levels were independent of previous training. However, the baseline CK level was dependent on the training that took place during 1 day before (F = 4.362, p < .01) and on the combined training on the previous 2 days (F = 4.606, p < .005). The present results suggest that FABP and CK could be used to monitor acute exercise and chronic exercise, respectively.

Research paper thumbnail of On-line flow displacement immunoassay for fatty acid-binding protein

Journal of Immunological Methods, 1998

In standard displacement flow immunoassays the analyte in the sample creates an active dissociati... more In standard displacement flow immunoassays the analyte in the sample creates an active dissociation of labelled antigens Ž. or antigen homologues from an antigen binding site of an immobilized antibody, after which the labelled substance is measured downstream. Such systems have been described for molecules up to 1 kDa. In this study, we demonstrate Ž displacement in a flow system for the detection of a small protein, cytoplasmic heart-type fatty acid-binding protein 15. kDa , a plasma marker for myocardial injury. The displacement system uses an inverse setup: enzyme labelled monoclonal antibodies are associated to immobilized antigen, and are displaced by analyte in the sample. The system permits detection Ž y1. Ž y1. of both physiological 2-12 mg l and pathological concentrations 12-2000 mg l of fatty acid-binding protein in an on-line flow system.

Research paper thumbnail of Continuous Lactate Measurement that Combines a Portable Ultrafiltration Storage Device with an Enzyme Sensor

Analytical Letters, 2000

The total weight of the collection system is only 8g, allowing free movement of the person being ... more The total weight of the collection system is only 8g, allowing free movement of the person being tested.

Research paper thumbnail of Continuous Ultraslow Microdialysis and Ultrafiltration for Subcutaneous Sampling As Demonstrated by Glucose and Lactate Measurements in Rats

Analytical Chemistry, 1998

Research paper thumbnail of Slow ultrafiltration for continuous in vivo sampling: application for glucose and lactate in man

Analytica Chimica Acta, 1999

Research paper thumbnail of Methodological aspects of glucose monitoring with a slow continuous subcutaneous and intravenous ultrafiltration system in rats

Biosensors and Bioelectronics, 1997

Research paper thumbnail of Early detection of acute myocardial infarction with the new marker Fatty Acid-Binding Protein : rapid testing and diagnostic value

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