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D Seidel

Publications and source records attributed to D Seidel.

At least 37 records · Page 2Linked to original sources
PubMed2001

Nucleosomes in serum as a marker for cell death.

The concentration of nucleosomes is elevated in blood of patients with diseases which are associated with enhanced cell death. In order to detect these circulating nucleosomes, we used the Cell Death Detection-ELISAplus (CDDE) from Roche Diagnostics (Mannheim, Germany) (details at http:\\biochem.roche.com). For its application in liquid materials we performed various modifications: we introduced a standard curve with nucleosome-rich material, which enabled direct quantification and improved comparability of the values within (CVintraassay:3.0-4.11%) and between several runs (CVinterassay:8.6-13.5%), and tested the analytical specificity of the ELISA. Because of the fast elimination of nucleosomes from circulation and their limited stability, we compared plasma and serum matrix and investigated in detail the pre-analytical handling of serum samples which can considerably influence the test results. Careless venipuncture producing hemolysis, delayed centrifugation and bacterial contamination of the blood samples led to false-positive results; delayed stabilization with EDTA and insufficient storage conditions resulted in false-negative values. At temperatures of -20 degrees C, serum samples which were treated with 10 mM EDTA were stable for at least 6 months. In order to avoid possible interfering factors, we recommend a schedule for the pre-analytical handling of the samples. As the first stage, the possible clinical application was investigated in the sera of 310 persons. Patients with solid tumors (n=220; mean=361 Arbitrary Units (AU)) had considerably higher values than healthy persons (n=50; mean=30 AU; p=0.0001) and patients with inflammatory diseases (n=40; mean= 296 AU; p=0.096). Within the group of patients with tumors, those in advanced stages (UICC 4) showed significantly higher values than those in early stages (UICC 1-3) (p=0.0004).

Anti-Bacterial Agents↗
PubMed2000

Novel synthesis of hybrid calixphyrin macrocycles

The reaction of benzaldehyde with excess pyrrole at room temperature in the absence of solvent affords a mixture of meso-substituted polypyrranes species. After separation by column chromatography, these may be used to prepare a range of calix[4]phyrin macrocycles by condensation with acetone under conditions of acid catalysis.

Journal Article↗
PubMed2000

Amplification of cyclin D1 gene in multiple myeloma: clinical and prognostic relevance.

Approximately 30% of myeloma patients express cyclin D1 RNA and protein. The low incidence of translocation t(11; 14) detected by conventional cytogenetics suggests that the up-regulation of cyclin D1 protein might result from other mechanisms as well as from gene amplification. Therefore, the frequency and the clinical and prognostic implications of cyclin D1 amplification were examined. We highly purified myeloma cells from bone marrow by magnetic cell sorting and analysed 50 myelomas by fluorescence in situ hybridization (FISH) using probes specific for cyclin D1 and 20 samples by immunoblotting to detect cyclin D1 expression. The amplification of cyclin D1 gene was found in 19 of 50 analysed patients and was associated with expression of cyclin D1 protein. The amplification correlated significantly with the bone marrow infiltration, plasma cell morphology and labelling index as well as serum beta2-microglobulin, C-reactive protein (CRP) and creatinine levels. In univariate analysis, the amplification of the cyclin D1 gene was a significantly unfavourable parameter with regard to overall survival (P = 0.0064) and progression-free survival (P = 0. 0005). In multivariate analysis, cyclin D1 amplification and serum beta2-microglobulin were independent and well-suited parameters for predicting survival. The detection of cyclin D1 amplification seems to be of promising prognostic value in multiple myeloma.

Adolescent↗
PubMed2000

Compound heterozygosity for a Wolman mutation is frequent among patients with cholesteryl ester storage disease.

Cholesteryl ester storage disease and Wolman disease are rare autosomal recessive lipoprotein-processing disorders caused by mutations in the gene encoding human lysosomal acid lipase. Thus far we have elucidated the genetic defects in 15 unrelated CESD patients. Seven were homozygotes for the prevalent hLAL exon 8 splice junction mutation which results in incomplete exon skipping, while eight probands were compound heterozygotes for E8SJM and a rare mutation on the second chromosome. In this report, we describe the molecular basis of CESD in three compound heterozygous subjects of Czech and Irish origin. RFLP and DNA sequence analysis revealed that they were heteroallelic for the common G(934)-->A substitution in exon 8 of the hLAL gene and a mutation which, if inherited on both alleles, would be expected to result in complete loss of enzyme activity and to cause Wolman disease. In patients A. M. and J. J., two nucleotide deletions in exons 7 and 10 were detected, involving a T at position 722, 723, or 724 and a G in a stretch of five guanosines at positions 1064;-1068 of the hLAL cDNA. Both mutations result in premature termination of protein translation at residues 219 and 336, respectively, and in the production of truncated, inactive enzymes. Subject D. H., in contrast, is a compound heterozygote for the Arg(44)-->Stop mutation previously described in a French CESD proband. Combined with data in the literature, our results demonstrate that compound heterozygosity for a mutation causing Wolman disease is common among cholesteryl ester storage disease patients.

Base Sequence↗
PubMed2000

Apolipoprotein B metabolism and the distribution of VLDL and LDL subfractions.

Apolipoprotein B (apoB) metabolism was investigated in 20 men with plasma triglyceride 0.66-2.40 mmol/l and plasma cholesterol 3.95-6. 95 mmol/l. Kinetics of VLDL(1) (S(f) 60-400), VLDL(2) (S(f) 20-60), IDL (S(f) 12-20), and LDL (S(f) 0;-12) apoB were analyzed using a trideuterated leucine tracer and a multicompartmental model which allowed input into each fraction. VLDL(1) apoB production varied widely (from 5.4 to 26.6 mg/kg/d) as did VLDL(2) apoB production (from 0.18 to 8.4 mg/kg/d) but the two were not correlated. IDL plus LDL apoB direct production accounted for up to half of total apoB production and was inversely related to plasma triglyceride (r = -0.54, P = 0.009). Percent of direct apoB production into the IDL/LDL density range (r = 0.50, P < 0.02) was positively related to the LDL apoB fractional catabolic rate (FCR). Plasma triglyceride in these subjects was determined principally by VLDL(1) and VLDL(2) apoB fractional transfer rates (FTR), i.e., lipolysis. IDL apoB concentration was regulated mainly by the IDL to LDL FTR (r = -0.71, P < 0.0001). LDL apoB concentration correlated with VLDL(2) apoB production (r = 0.48, P = 0.018) and the LDL FCR (r = -0.77, P < 0. 001) but not with VLDL(1), IDL, or LDL apoB production. Subjects with predominantly small, dense LDL (pattern B) had lower VLDL(1) and VLDL(2) apoB FTRs, higher VLDL(2) apoB production, and a lower LDL apoB FCR than those with large LDL (pattern A). Thus, the metabolic conditions that favored appearance of small, dense LDL were diminished lipolysis of VLDL, resulting in a raised plasma triglyceride above the putative threshold of 1.5 mmol/l, and a prolonged residence time for LDL. This latter condition presumably permitted sufficient time for the processes of lipid exchange and lipolysis to generate small LDL particles.

Adult↗
PubMed2000

Calixphyrins: Novel Macrocycles at the Intersection between Porphyrins and Calixpyrroles This work was supported by the National Institutes of Health (CA-68682, GM-58907, and TW-00682 to J.L.S.), the National Science Foundation (CHE-9725399 to J.L.S. and CHE-9807702 to V.L. for the purchase of the Nonius Kappa CCD), the Howard Hughes Foundation (V.K. and J.L.S.), the Grant Agency of the Czech Republic (No. 203/97/1099 to V.K.), the Ministry of Education (No. VS-97135 and Project CEZ: J19/98: 223400008 to V.K.), and the Howard Hughes Medical Institute (74195-541101 to V.K.).

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Journal Article↗
PubMed1999

Heparin-mediated extracorporeal LDL/fibrinogen precipitation--H.E.L.P.--in coronary and cerebral ischemia.

Cerebral and myocardial infarctions share common aspects of pathobiochemistry. The central problem is the oxygen supply of the infarcted region. To maintain this supply, H.E.L.P.-apheresis (Heparin-mediated Extracorporeal LDL/Fibrinogen Precipitation) has already proven beneficial in the prevention and therapy of myocardial infarction. Since H.E.L.P.-apheresis can lower significantly plasma viscosity and erythrocyte aggregation without reducing the oxygen transport capacity, patients with cerebral infarction (stroke) may also benefit from our experiences in myocardial ischemia. The system is designed to remove selectively plasma fibrinogen, LDL-cholesterol and lipoprotein(a) from blood circulation, simultaneously. The removal of the plasma compounds is achieved by extracorporeal precipitation with heparin at low pH. Excess heparin is completely removed by an adsorber before the plasma is given back to the patient. H.E.L.P.-apheresis has proved to be safe in patients with coronary heart disease and allows a controlled reduction of thrombogenic plasma compounds. It is therefore hoped to be effective also in patients with acute ischemic stroke.

Blood Component Removal↗
PubMed1999

Alpha-tocopherol down-regulates scavenger receptor activity in macrophages.

The aim of this study was to investigate the effect of alpha-tocopherol on scavenger receptor (SR) activity, SR class A (SR-A) mRNA expression and transcriptional regulation in macrophages. Scavenger receptor activity was determined quantitatively by uptake of DiI-acLDL (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein) in rabbit peritoneal macrophages and human monocytes/macrophages in the presence and absence of different tocopherol homologues. SR-A mRNA expression was determined by Northern blotting, the activity of the transcription factor activator protein-1 (AP-1) by electrophoretic mobility shift assay. We could demonstrate that alpha-tocopherol down-regulates scavenger receptor activity in macrophages in a dose-dependent manner. Scavenger receptor activity was reduced by 13, 16, 18 and 24% in the presence of 1, 5, 10 and 50 microM alpha-tocopherol, respectively. This effect was associated with a reduced SR-A mRNA expression and activity of AP-1 binding transcription factors in the presence of alpha-tocopherol. The activity of scavenger receptors in human monocyte derived macrophages incubated with 100 microM alpha-tocopherol for 15 days was reduced up to 60%. Interestingly, gamma-tocopherol, which is a homologue of alpha-tocopherol with a comparable antioxidative capacity, showed only a weak suppression of SR activity, SR-A expression and AP-1 activity. Our observations point to the conclusion that the reduction of SR-A expression and activity in presence of alpha-tocopherol is possibly related to its direct action on cell signaling.

Animals↗
PubMed1999

Combination therapy with tacrolimus and mycophenolate mofetil following cardiac transplantation: importance of mycophenolic acid therapeutic drug monitoring.

BACKGROUND: Interest has recently been expressed in tacrolimus and mycophenolate mofetil (MMF), two potent immunosuppressants, for a variety of transplant indications. The efficacy of this combination was assessed as primary therapy following cardiac transplantation. METHODS: Forty-five patients were enrolled; 15 into Phase I and 30 to Phase II of the study. Intravenous tacrolimus was administered for 2-3 days to all patients prior to conversion to oral therapy; target blood concentrations were 10-15 ng/mL. Treatment also consisted of steroids and MMF. During Phase I, a fixed 2 g/day dose of MMF was given whilst doses were adjusted according to mycophenolic acid (MPA) plasma levels during Phase II (target range 2.5-4.5 microg/mL). Mean follow-up was 696 +/- 62 days and 436 +/- 88 days for Phases I and II, respectively. RESULTS: Phase I: Patient survival was 100%. Rejection was diagnosed in 66.7% of patients (mean number of episodes per patient 1.33 +/- 1.18). Retrospective analyses indicated that whereas mean MPA plasma levels >3.0 microg/mL were not associated with rejection, no correlation was found with tacrolimus blood concentrations. Phase II: A survival rate of 96.7% was evident, one patient having died from aspergillosis. Diagnoses of rejection were made in 10.0% of patients (0.10 +/- 0.31 episodes per patient) and confounding factors were present in all 3 cases. MPA trough levels were 1.0 +/- 0.3 microg/mL at this time. Resolution was apparent following pulse steroid therapy. Steroids were successfully withdrawn from all patients who completed 6 months' treatment. CONCLUSIONS: Combination therapy with tacrolimus and MMF is associated with suppression of acute myocardial rejection; however, this is dependent upon routine therapeutic drug monitoring.

Adolescent↗
PubMed1999

Coronary risk factor management for the prevention and treatment of graft vessel disease in heart transplant patients.

There is increasing evidence that atherogenic risk factors largely contribute to the pathogenesis of graft vessel disease (GVD) after heart transplantation. Initial endothelial damage of the transplant heart derives from reperfusion ischemia during operation, repeated infections, and rejection episodes. Immunosuppressive medication considerably increases low density lipoprotein (LDL) cholesterol, lipoprotein(a), and fibrinogen blood levels, which in turn further damage the endothelium of the graft coronaries. Probably, this interplay of immunological and atherogenic factors accounts for the rapid development of GVD and its poor prognosis. The rapidity of the disease process makes it necessary to eliminate important risk factors as early and as efficiently as possible. Therefore, we studied whether heart transplant patients could benefit from a combined treatment of statins and apheresis heparin extracorporeal LDL/fibrinogen precipitation (HELP), which has already been shown to be beneficial for the treatment of advanced coronary artery disease. Such a combined treatment allows simultaneous and drastic reduction of LDL, lipoprotein(a), and fibrinogen blood levels and significantly prevented GVD. Moreover, it did not affect the prevention of rejections and infections, respectively.

Blood Component Removal↗
PubMed1999

Clinical utility of LDL-apheresis in the treatment of sudden hearing loss: a prospective, randomized study.

Although the pathogenesis of sudden hearing loss (SHL) is not as yet known, the clinical picture and the frequent association with vascular risk factors make an ischaemic event likely. This study aimed to assess the effect of an extracorporeal procedure (H.E.L.P.) in removing LDL-cholesterol, fibrinogen and lipoprotein (a) from the plasma, on the recovery of hearing SHL. This procedure using the HELP-system was compared with the usual standard treatment with prednisolone, dextranes and pentoxifyllin. We undertook a single centre, prospective, randomized study in which 18 patients were assigned to H.E.L.P.-apheresis and 9 patients were assigned to standard treatment (2:1 randomization). Audiometric and laboratory testing was performed at baseline, 24 h and 6 weeks after start of treatment. Primary endpoint was the improvement of the average pure-tone threshold between 0.125 and 8 kHz after 24 h. Twenty-four hours after H.E.L.P. treatment average pure-tone threshold recovered by 10.4 dB and by 26.4 dB after 6 weeks. The recovery of hearing of the standard treated patients was 5.8 dB and 16.8 dB after 24 h and 6 weeks respectively. LDL-cholesterol, fibrinogen and lipoprotein (a) were significantly reduced in the HELP treated patients compared with standard therapy, resulting in a significant improve in plasma viscosity, erythrocyte aggregation and resistance to oxidative stress of LDL particles. Our results suggest that the clinical outcome of SHL after a single extracorporeal LDL-apheresis is superior or at least equal to the more expensive standard treatment with prednisolone, dextranes and pentoxifyllin. Re-establishment of vascular endothelial function and improved blood rheology may be the underlying cause. These results must be confirmed in larger-scale trials.

Acute Disease↗
PubMed1999

Evaluation of the first automated thyroglobulin assay.

The aim of this study was to investigate technical and analytical performance of the first automated thyroglobulin (Tg) assay (DPC-Immulite; Diagnostic Products Corporation, Los Angeles, USA). In imprecision studies using several human serum pools ranging from 21 to 58 replicates, a coefficient of variation of 9.0% was obtained at a mean Tg concentration of 0.84 ng/ml and of 6.1% at a Tg concentration of 62.1 ng/ml. In a method comparison with a non-automated assay (BRAHMS LUMItest Tg, BRAHMS, Berlin, Germany) using 383 sera of 303 patients with thyroid carcinoma, regression analysis according to Passing and Bablock yielded in the following equation: Immulite Tg = 1.6 x BRAHMS Tg-0.1 ng/ml (Pearson's r = 0.979). Sera obtained from 59 patients with thyroid carcinoma enabled comparative follow-up studies; in all cases qualitative agreement was found with regard to increase or decrease of serum Tg; in eight cases, however, Tg was detected with the Immulite assay but not with the BRAHMS assay. Further follow-up proved the presence of thyroid tissue in these patients. From these and further methodological data (dilution linearity, interference studies, carry-over study, high-dose hook properties, and short report time) it is concluded that the DPC-Immulite Tg assay meets the requirements of routine diagnostic use.

Automation↗