Papers by Lambert Dikkeschei
Annals of Clinical Biochemistry: International Journal of Laboratory Medicine, 2004
Background: In patients with acute myocardial infarction, estimation of infarct size by cumulativ... more Background: In patients with acute myocardial infarction, estimation of infarct size by cumulative lactate dehydrogenase release at 72 h (LDHQ72) is a simple and widely used method. Our objective was to study the value of estimating infarct size, by the cumulative release of LDH over 72, 60, 48 and 36 h in predicting left ventricular ejection fraction (LVef) and cardiac death at 1 year. Methods: In the Zwolle Infarction Study infarct size estimated as LDHQ was calculated in 1224 patients treated with primary percutaneous coronary intervention for acute myocardial infarction between December 1993 and June 2001. Patients were categorized as having small (LDHQ72<800 U/L), medium (LDHQ72 800-2500 U/L) or large (LDHQ72>2500 U/L) myocardial infarction. Results: LDHQ72 was closely correlated with LDHQ60, LDHQ48 and LDHQ36 ( r = 0.998, 0.993 and 0.987, respectively, P <0.0001). The relations between LDHQ infarct size classification and mean LVef (51% vs 45% vs 35%, P <0.001) or ...
Clinical Chemistry
4 Nonstandard abbreviations: ED, emergency department; H-index, hemolysis index; RCV, reference c... more 4 Nonstandard abbreviations: ED, emergency department; H-index, hemolysis index; RCV, reference change value; FP, familial pseudohyperkalemia. ensuring that questions related to the accuracy or integrity of any part of the article are appropriately investigated and resolved. M.J. Vos, statistical analysis; J.W. Bouwhuis, provision of study material or patients; L.D. Dikkeschei, provision of study material or patients.
Practical Laboratory Medicine
Atherosclerosis
In NSTEMI patients, there was a trans-cardiac decrease in CRP across the myocardium. • This decre... more In NSTEMI patients, there was a trans-cardiac decrease in CRP across the myocardium. • This decrease was irrespective of time of presentation, infarct size and culprit lesion location. • There was no trans-lesional gradient across the culprit coronary artery lesion. • Both injured and non-injured myocardium contributes to the decrease in CRP.
Pediatr Allergy Immunol, 2010
To cite this article: Baatenburg de Jong A, Dikkeschei LD, Brand PLP. Sensitization patterns to f... more To cite this article: Baatenburg de Jong A, Dikkeschei LD, Brand PLP. Sensitization patterns to food and inhalant allergens in childhood: A comparison of nonsensitized, monosensitized, and polysensitized children.
Clinical Chemical Laboratory Medicine, 2000
The Roche CARDIAC proBNP point-of-care (POC) test is the first test intended for the quantitative... more The Roche CARDIAC proBNP point-of-care (POC) test is the first test intended for the quantitative determination of N-terminal pro-brain natriuretic peptide (NT-proBNP) in whole blood as an aid in the diagnosis of suspected congestive heart failure, in the monitoring of patients with compensated left-ventricular dysfunction and in the risk stratification of patients with acute coronary syndromes. A multicentre evaluation was carried out to assess the analytical performance of the POC NT-proBNP test at seven different sites. The majority of all coefficients of variation (CVs) obtained for within-series imprecision using native blood samples was below 10% for both 52 samples measured ten times and for 674 samples measured in duplicate. Using quality control material, the majority of CV values for day-to-day imprecision were below 14% for the low control level and below 13% for the high control level. In method comparisons for four lots of the POC NT-proBNP test with the laboratory reference method (Elecsys proBNP), the slope ranged from 0.93 to 1.10 and the intercept ranged from 1.8 to 6.9. The bias found between venous and arterial blood with the POC NT-proBNP method was &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; or =5%. All four lots of the POC NT-proBNP test investigated showed excellent agreement, with mean differences of between -5% and +4%. No significant interference was observed with lipaemic blood (triglyceride concentrations up to 6.3 mmol/L), icteric blood (bilirubin concentrations up to 582 micromol/L), haemolytic blood (haemoglobin concentrations up to 62 mg/L), biotin (up to 10 mg/L), rheumatoid factor (up to 42 IU/mL), or with 50 out of 52 standard or cardiological drugs in therapeutic concentrations. With bisoprolol and BNP, somewhat higher bias in the low NT-proBNP concentration range (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;175 ng/L) was found. Haematocrit values between 28% and 58% had no influence on the test result. Interference may be caused by human anti-mouse antibodies (HAMA) types 1 and 2. No significant influence on the results with POC NT-proBNP was found using volumes of 140-165 muL. High NT-proBNP concentrations above the measuring range of the POC NT-proBNP test did not lead to false low results due to a potential high-dose hook effect. The POC NT-proBNP test showed good analytical performance and excellent agreement with the laboratory method. The POC NT-proBNP assay is therefore suitable in the POC setting.
Journal of chromatography, Jan 29, 1985
The mass fragmentographic determination of medroxyprogesterone acetate (MPA) in serum, using as i... more The mass fragmentographic determination of medroxyprogesterone acetate (MPA) in serum, using as internal standard medroxyprogesterone propionate (MPP) synthesized from MPA, is described. After addition of MPP, the sera are extracted on Sep-Pak C18 cartridges and MPA and MPP are detected as their respective 3-enol trifluoroacyl esters. Serum samples from 84 patients with breast cancer, daily receiving MPA orally, were determined showing a large variation in MPA concentrations (4-349 ng/ml). Our proposed gas chromatographic-mass spectrometric (GC-MS) method, which can be considered as a reference, was compared with a radioimmunoassay (RIA) method showing a correlation coefficient of 0.73 (n = 69; p much less than 0.001). The assay was also used to determine sequential serum levels of patients receiving a single oral dose of MPA. With only minor adjustments, the GC-MS method allows the determination of serum concentrations of related steroids such as megestrol acetate and cyproterone a...
Journal of chromatography, Jan 13, 1990
A reversed-phase high-performance liquid chromatographic method with ultraviolet detection of meg... more A reversed-phase high-performance liquid chromatographic method with ultraviolet detection of megestrol acetate and cyproterone acetate in human sera is described. The proposed assay is linear up to 1400 ng/ml (r = 0.999) and has a detection limit of 5 ng/ml. Recoveries of both compounds in spiked sera were ca. 95%; inter-assay coefficients of variation were 4.0 and 3.1% and intra-assay values were 1.3 and 1.4%, respectively. For validation of the method we also developed a gas chromatographic-mass spectrometric method for both steroids. The results obtained by the two methods showed good correlation: for megestrol acetate r = 0.98, n = 31, p less than 0.0001, and for cyproterone acetate r = 0.94, n = 0, p less than 0.0001. Large inter-individual differences in the serum concentrations of both substances were found in groups of patients with metastatic breast cancer receiving the same oral load of either steroid.
The Journal of Steroid Biochemistry and Molecular Biology, 1996
The tritium water release assay, originally described for the analysis of aromatase activity in p... more The tritium water release assay, originally described for the analysis of aromatase activity in placental tissue, was used to estimate aromatase activity in breast tissue samples. The lower activity in this tissue necessitates longer incubation times and thus optimization of the assay conditions. To prevent oxidative and proteolytic inactivation of aromatase, dithiothreitol and albumin were added to the incubation mixture. Extra NADPH, cofactor in the aromatase reaction, also improved reaction rate in placental incubations, but after approximately 120 min activity rapidly decreased. Inhibitors gradually produced during the incubation could explain this phenomenon. Quantitative gas chromatography-mass spectrometry (GC-MS) analyses of testosterone, oestradiol, oestrone and androstenedione after incubation with non-labelled androstenedione proved that a substantial amount of the substrate is converted into testosterone. Qualitative GC-MS steroid profiling of the incubation mixture demonstrated the presence of hydroxylated oestradiol and hydroxylated testosterone, produced during incubation, which could have caused partial aromatase inhibition. The adjusted assay was used to analyse 84 breast tissue samples, histologically classified as normal, adenoma or carcinoma. Aromatase activity was found in 56% of all samples and ranged from 0.6 to 26 pmol oestrogen/g protein per hour. Aromatase positivity was found in 80% of the normal samples, 56% of the adenoma samples and 48% of the carcinoma samples. Although carcinoma samples were less often aromatase positive than normal tissue samples (chi2 = 4.80; P &amp;amp;amp;amp;lt; 0.050) there was no difference in absolute aromatase activity. Because no less than approximately 50% of the carcinomas contained aromatase activity and because of the non-routine character of the assay we conclude that it is justified to start aromatase inhibition therapy without previous knowledge of the aromatase status.
Maturitas, 1988
A phase II study with cyproterone acetate (CPA) was done as the primary treatment in female breas... more A phase II study with cyproterone acetate (CPA) was done as the primary treatment in female breast cancer patients. Twenty-three patients, mean age 64 years, range 52-75 years, were entered and treated with CPA 400 mg daily. Twenty patients were evaluable and responses were sparse. There was one partial and one complete remission, 17 patients were stable and one patient progressed within 3 months. Side-effects were frequent: five patients complained of nausea, three had severe weight loss, one suffered from depression and seven showed disturbed liver function tests. Six patients had to stop treatment for side-effects, while two other patients were taken off treatment because they developed an acute necrotizing hepatitis. The hepatitis recovered after drug withdrawal in both patients. The serum levels of CPA, cortisol, androstenedione, DHAS, LH, FSH and prolactin were measured during CPA treatment. The levels of cortisol and androstenedione did not change, while LH, FSH and DHAS were suppressed. The DHAS showed an inverse relation to serum CPA concentrations. The prolactin levels rose uniformly. The therapeutic effect of CPA in postmenopausal patients with advanced breast cancer is disappointing, and inferior to that of other progestins. Side-effects are frequent, possibly as a result of the high dosage used in this study. The hormonal changes are different from those of other progestins, which may explain the different efficacies.
Clinical Endocrinology, 1993
We developed an assay for delta-5-androstenediol (adiol) and delta-5-androstenediol-3-sulphate (a... more We developed an assay for delta-5-androstenediol (adiol) and delta-5-androstenediol-3-sulphate (adiol-3S) in serum and adiol and total adiol sulphate (adiol-S) in urine. An analytical procedure using HPLC and gas chromatography-mass spectrometry was devised and tested for its reliability. After addition of deuterated androstenediol as internal standard, serum and urine samples were extracted. Steroid sulphates were hydrolysed. The extracts and hydrolysates were purified on HPLC, adiol was derivatized using heptafluorobutyric anhydride and finally quantified by gas chromatography-mass spectrometry. The assay is accurate and reproducible. The coefficient of variation (CV) for the determination of adiol in serum samples is 4% (intra-assay) and 9% (interassay) and for urine samples 3 and 8% respectively. The intra-assay CV for the adiol-3S analyses is 5% for serum and 2% for urine samples while the interassay CV values for adiol-3S are 10% for serum and 7% for urine samples. The recovery of adiol and adiol-3S from serum and urine samples is 97%. The developed assay meets the analytical demands needed for clinical applications.
Nederlands tijdschrift voor geneeskunde, Jan 25, 2002
Wolfram syndrome patients are mainly characterised by juvenile onset diabetes mellitus and optic ... more Wolfram syndrome patients are mainly characterised by juvenile onset diabetes mellitus and optic atrophy. A synonym is the acronym DIDMOAD: diabetes insipidus, diabetes mellitus, optic atrophy, deafness. Diabetes insipidus and sensorineural high-frequency hearing impairment are important additional features. This rare autosomal recessively inherited neurodegenerative syndrome is caused by mainly inactivating mutations in the WFS1 gene. It is located at chromosome 4p16 and encodes wolframin, a transmembrane protein. No function has yet been ascribed to this protein.
Kidney International, 1993
Role of elevated lecithin: Cholesterol acyltransferase and cholesteryl ester transfer protein act... more Role of elevated lecithin: Cholesterol acyltransferase and cholesteryl ester transfer protein activities in abnormal lipoproteins from proteinuric patients. Lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) are key factors in the esterification of free cholesterol, and the distribution of cholesteryl ester among lipoproteins in plasma. Alterations in these processes may play a role in the lipoprotein abnormalities associated with glomerular proteinuria. The activities of LCAT and CETP were measured using excess exogenous substrate assays in nine patients with nephrotic-range proteinuria and in 18 matched controls. The proteinuria-lowering effect of four weeks of angiotensin converting enzyme (ACE) inhibition with enalapril was also studied. Plasma very low lipoprotein and low density lipoprotein (VLDL and LDL) cholesterol, triacyiglycerol and apolipoprotein B levels were significantly elevated in the patients compared with controls. High density lipoprotein (HDL) total cholesterol, free cholesterol, cholesteryl ester and the free cholesterol/cholesteryl ester ratio in HDL were lower. Total plasma apolipoprotein A1 was normal. Plasma LCAT and CETP activities were elevated in the patients by 30% (P < 0.01) and by 39% (P < 0.01), respectively, and were both inversely related to serum albumin. VLDL and LDL cholesterol levels were positively related to LCAT and CETP activities, whereas the HDL free cholesterol content was inversely related to LCAT activity. ACE inhibition resulted in a 40% reduction of proteinuria, a partial normalization of LCAT activity, and a decrease in VLDL and LDL cholesterol. In conclusion, elevated activities of LCAT and CETP may provide a mechanism that contributes to the low proportion of cholesterol in HDL relative to that in VLDL and LDL, as well as to the compositional changes of HDL seen in glomerular proteinuria. Such abnormalities could contribute to accelerated development of atherosclerosis in proteinuric states.
Expert Opinion on Therapeutic Targets, 2009
Dyslipidemia contributes to increased cardiovascular risk in nephrotic syndrome. We questioned wh... more Dyslipidemia contributes to increased cardiovascular risk in nephrotic syndrome. We questioned whether reduction in proteinuria not only lowers low-density lipoprotein cholesterol (LDL-C), but also high-density lipoprotein cholesterol (HDL-C) and cholesteryl ester transfer protein (CETP) mass and whether changes in HDL-C were related to changes in plasma adiponectin. Thirty-two non-diabetic proteinuric patients (12 on statin therapy), were followed during two double blind 6-week periods of placebo and treatment (low sodium + 100mg losartan + 25 mg hydrochlorothiazide). With placebo HDL-C was lower but LDL-C and CETP were not different in proteinuric patients compared with matched controls. LDL-C, HDL-C and CETP decreased upon proteinuria reduction. The decrease in LDL-C correlated with the drop in CETP and the degree of proteinuria reduction. HDL-C also decreased in proportion to proteinuria lowering. Individual changes in HDL-C were correlated with changes in adiponectin. LDL-C lowering upon robust reduction of proteinuria may be affected by changes in plasma CETP mass, but this treatment also decreases HDL-C in relation to the degree of proteinuria reduction. This adverse effect on HDL-C may in part be attributable to changes in adiponectin.
European Journal of Clinical Investigation, 1994
The mechanisms responsible for the decreased high density lipoprotein (HDL) cholesterol levels as... more The mechanisms responsible for the decreased high density lipoprotein (HDL) cholesterol levels associated with obesity and insulin resistance are not well understood. Lecithin: cholesterol acyltransferase (LCAT) and cholesterol ester transfer protein (CETP) are key factors in the esterification of cholesterol in HDL and the subsequent transfer of cholesteryl ester towards apolipoprotein B-containing lipoproteins. Phospholipid transfer protein (PLTP) may be involved in the regulation of HDL particle size. We therefore measured the activities of LCAT, CETP and PLTP using exogenous substrate assays, as well as lipids, lipoproteins, insulin and C-peptide in fasting plasma from eight healthy obese men (body mass index &gt; 27 kg m-2) and 24 non-obese subjects. The obese men had lower levels of HDL cholesterol (P &lt; 0.05) and higher levels of plasma triglycerides (P &lt; 0.05), insulin (P &lt; 0.05) and C-peptide (P &lt; 0.01), as compared to the quartile of subjects with the lowest body mass index (BMI &lt; 22.4 kg m-2). CETP and PLTP activities were elevated in the obese men by 35% (P &lt; 0.01) and by 15% (P &lt; 0.05), respectively. LCAT activity was comparable among the quartiles. Linear regression analysis showed that CETP activity was positively correlated with body mass index (P &lt; 0.02), fasting blood glucose (P &lt; 0.05) and plasma C-peptide (P &lt; 0.05). PLTP activity was positively related to body mass index (P &lt; 0.01), waist to hip circumference ratio (P &lt; 0.001), as well as to fasting blood glucose (P &lt; 0.05) and plasma C-peptide (P &lt; 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
European Journal of Clinical Investigation, 2007
Sir, It is increasingly recognized that inflammation is important for the development of atherosc... more Sir, It is increasingly recognized that inflammation is important for the development of atherosclerosis. Many studies have demonstrated that high plasma levels of C-reactive protein (CRP) , a marker of low-grade inflammation, predict incident cardiovascular disease both in men and in women, independently of conventional risk factors . Interestingly, with few exceptions [5], plasma CRP, measured with highly sensitive assays, has been reported to be higher in women compared to men [4,6 -9]. This has led to the suggestion that gender-specific CRP cutoff values should be applied when using this marker of low-grade inflammation for cardiovascular risk assessment . However, the mechanisms for this gender difference in CRP are unknown. Of relevance, plasma leptin levels are higher in women than in men . Leptin is able to promote atherosclerosis, contributes to a pro-inflammatory state , and its plasma concentration is positively correlated with CRP in both genders .
Clinical Laboratory, 2012
Plasma cholesteryl ester transfer (CET) from high density lipoproteins (HDL) to very low and low ... more Plasma cholesteryl ester transfer (CET) from high density lipoproteins (HDL) to very low and low density lipoproteins (VLDL+LDL) may predict (subclinical) atherosclerosis. We tested the extent to which plasma CET and cholesterol esterification (EST) are decreased by statin and fibrate combination therapy compared to statin and fibrate administration alone in type 2 diabetic patients. Plasma CET and EST were measured by isotope assays in 14 type 2 diabetic patients, in whom a randomized placebo-controlled crossover study was carried out (8 weeks treatment with simvastatin (40 mg daily), bezafibrate (400 mg daily) and their combination). Plasma CET and EST from diabetic patients were compared with 42 non-diabetic control subjects with similar triglyceride levels. Plasma CET and EST were elevated in diabetic patients at baseline compared to control subjects (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), and were correlated positively with non-HDL cholesterol and triglycerides in non-diabetic subjects and in diabetic patients at baseline (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). Decreases in CET during combined treatment (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) were not greater than the changes during simvastatin and bezafibrate monotherapy (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.20). EST only decreased during bezafibrate therapy (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Changes in CET during treatment were correlated positively with changes in non-HDL cholesterol (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) and triglycerides (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001). Changes in HDL cholesterol were related inversely to changes in CET (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). Diabetes-associated plasma CET elevations are ameliorated by statin and fibrate monotherapy, but combined lipid lowering drug treatment does not additively lower CET. CET lowering likely contributes to HDL cholesterol changes during statin and fibrate administration.
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Papers by Lambert Dikkeschei