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Biomedical subjects

W Gross

Publications and source records attributed to W Gross.

At least 73 records · Page 4Linked to original sources

Long-term therapy with the new glucocorticosteroid deflazacort in rheumatoid arthritis. Double-blind controlled randomized 12-months study against prednisone.

The long-term anti-inflammatory and immunosuppressive properties and the safety of deflazacort (Calcort, CAS 14484-47-0) were assessed investigating the effect on clinical symptoms and safety parameters in patients with rheumatoid arthritis compared to prednisone as standard therapy in a randomized double-blind controlled clinical trial. Monitoring was performed according to GCP-guidelines closely in order to have a maximum of the patients entered completed at the end of the 12-month therapy with high data quality. 76 patients, meeting the criteria for classical or definite rheumatoid arthritis and requiring corticosteroid therapy, were randomly allocated to a 12-months treatment with either deflazacort (6 mg/tablet) or the corticoid standard prednisone (5 mg/tablet). Steady state dosage between 1/2 and 3 tablets per day was individually adjusted according to the severity of the clinical symptoms. Due to the close monitoring of the trial in the 6 study centres, 25 patients completed 12 months of deflazacort and 28 patients 12 months of prednisone treatment, being controlled 7 times during the trial. Five efficacy parameters were assessed at each visit: Ritchie Index, duration of morning stiffness, grip strength, effective dosage of study medication and global assessment of disease status. Following safety and tolerance parameters were controlled during the trial: vital signs, weight, Cushing's symptoms and adverse events at each visit; 32 laboratory parameters at 6 visits; ECG at 3 visits; and the global tolerance was assessed at the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Heterogeneous lipoprotein (a) size isoforms differ by their interaction with the low density lipoprotein receptor and the low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor.

Lipoprotein (a) (Lp(a)) is a complex of low density lipoprotein (LDL) with apolipoprotein (apo) (a). To examine the size distribution of Lp(a), plasma was separated by fast flow gel filtration and Lp(a):B complexes were determined in the eluate by enzyme immunoassays, in which detection was performed with monoclonal antibodies specific for apoB. Lp(a):B particles displayed apparent molecular masses (M(r)) of 2 x 10(6) to at least 10 x 10(6). Lp(a) size isoforms differed by the expression of apoB epitopes and their interaction with cultured human skin fibroblasts. LDL was more effective in inhibiting binding, uptake, and degradation of low M(r) Lp(a) than of high M(r) Lp(a). In contrast, Glu-plasminogen, alpha 2-macroglobulin and tissue-type plasminogen activator were more effective in competing for the cellular degradation of high M(r) Lp(a) than of low M(r) Lp(a). Ligand blotting revealed that Lp(a) bound to the low density lipoprotein receptor, the low density lipoprotein receptor-related protein/alpha 2-macroglobulin receptor (LRP) and to two other endosomal membrane proteins. We propose that the LDL receptor preferentially internalizes low M(r) Lp(a), whereas LRP may have a role in the clearance of high M(r) Lp(a).

Cells, Cultured↗

Determination of lipoprotein(a): enzyme immunoassay and immunoradiometric assay compared.

Lipoprotein(a) (Lp(a)) concentration in plasma is a strong independent risk factor for pre-mature atherosclerosis. Lp(a) closely resembles LDL. Its protein moiety contains apolipoprotein (apo) B-100 and apo(a). Two enzyme immunoassays (EIAs) for Lp(a) have been developed. In both, polyclonal antibodies for apo(a) are used as capturing antibodies. In the first, Lp(a) is detected with anti-apo(a) (apo(a)-EIA). In the second, detection is carried out with anti-apo B (Lp(a):B-EIA). Neither plasminogen nor LDL cross-reacted in the assays. Lp(a) was also measured using a commercial sandwich immunoradiometric assay (IRMA). This assay uses two monoclonal antibodies for apo(a). One of them, the solid phase antibody, cross-reacted with plasminogen. However, at physiological plasminogen concentrations there was no competition for solid phase binding sites. A quantity of plasma samples (201) were assayed for Lp(a) with the three methods. The best correlation was obtained between the IRMA and the Lp(a):B-EIA (r = 0.909). Correlations between the apo(a)-EIA and the IRMA or the Lp(a):B-EIA were 0.763 and 0.695, respectively. As compared to the EIAs, the IRMA overestimated Lp(a) by about 30%. It is concluded that both the Lp(a):B-EIA and the IRMA reflect the concentration of Lp(a) particles in plasma. In contrast, the apo(a)-EIA measures apo(a) antigen and may therefore be susceptible to the size polymorphism of apo(a).

Humans↗

The value of indirect immunofluorescence and solid phase techniques for ANCA detection. A report on the first phase of an international cooperative study on the standardization of ANCA assays. EEC/BCR Group for ANCA Assay Standardization.

This study describes the results of phase I of an international effort to develop and standardize assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). 12 sera, four of which were selected for their potential to cause problems in the detection of various ANCA specificities, were analyzed in the standard indirect immunofluorescence (IIF) test and in ELISAs for ANCA routinely performed in the seven participating laboratories. The IIF methodology differed with respect to the dilution of the serum being screened and the concentration of the conjugate used. Results from sera with high ANCA titers were similar, although the quantitative values could not be compared. In sera containing rheumatoid factor and anti-nuclear antibodies (ANA), ANCA-unrelated staining patterns were observed. Six antigen preparations were used in ELISA for the detection of cANCA. In ELISA with purified proteinase-3 all three cANCA sera were positive, but not anti-myeloperoxidase (MPO) or anti-lactoferrin (LF) positive sera. The other assays were less sensitive or gave inconsistent results. Various preparations of purified MPO and LF used in ELISA were readily recognized by anti-MPO and anti-LF positive sera. From this study it can be concluded that the IIF test, although performed with different methods, shows comparable results using strongly positive sera. In general solid phase assays for cANCA detection are not well standardized and need improvement although the purified proteinase-3 ELISA is possibly an exception. MPO and LF can be used in ELISA procedures for the detection of pANCA-related antibodies.

Antibodies, Antineutrophil Cytoplasmic↗

Characterization of the gene for apolipoprotein E5-Frankfurt (Gln81->Lys, Cys112->Arg) by polymerase chain reaction, restriction isotyping, and temperature gradient gel electrophoresis.

A new apolipoprotein (apo) E variant, apoE5-Frankfurt, was identified in a 43-year-old male with moderate hypercholesterolemia. On isoelectric focusing in an immobilized pH gradient, apoE5-Frankfurt migrated to a position more cathodic than apoE4 (Cys112->Arg). On sodium dodecyl sulfate-gel electrophoresis, its apparent molecular weight could not be distinguished from that of the three common apoE isoforms (E2, E3 and E4). Restriction isotyping with CfoI (HhaI) showed that apoE5-Frankfurt had arginine in positions 112 and 158 of the mature protein, suggesting that the mutation accounting for the additional positive charge had occurred in an epsilon 4 allele. The third and the fourth exon of the apoE gene were amplified using the polymerase chain reaction and analyzed by temperature gradient gel electrophoresis. This suggested that there were two mutations in the fourth exon of the mutant allele. Cloning and sequencing disclosed that, apart from the exchange of arginine for cysteine in position 112, a C to A substitution replaced glutamine (CAA) in position 81 by lysine (AAA).

Adult↗

Typing of the 3' hypervariable region of the apolipoprotein B gene: approaches, pitfalls, and applications.

Apolipoprotein B-100 is the principal protein component of lipoproteins with very low, intermediate, and low density. The interaction of apoB-100 with low density lipoprotein (LDL) receptors is responsible for the uptake of LDL into cells. An AT-rich hypervariable region is located adjacent to the 3' end of the apoB gene. It consists of a variable number of tandemly repeated sequences (VNTR). Two approaches were used to analyze this polymorphism. In both, the region harboring the VNTR was amplified with the polymerase chain reaction (PCR). In the first method, fluorescently labeled primers were used in the PCR reactions and products were separated in agarose gels by means of an automated fluorescent fragment analyzer. In the second method, PCR products were analyzed in denaturing polyacrylamide gels and detected with silver staining. Even in the highly sophisticated automated system, agarose gel electrophoresis did not always enable unequivocal assignment of VNTR alleles. In contrast, denaturing polyacrylamide gel electrophoresis made it possible to distinguish the 15 bp differences between the VNTR alleles in a precise and simple manner. The VNTR polymorphism was typed in 234 individuals. Among these were 136 patients with coronary artery disease and 74 healthy controls. Thirteen alleles could be distinguished. The allele containing 49 repeats (VNTR-49) was found in 9.2% of the coronary artery disease patients and in 4.7% of the controls. Thus, the VNTR-49 allele increases relative coronary risk by about twofold. It is concluded that the apoB VNTR polymorphism is a potentially useful genetic marker. Since agarose gel electrophoresis may lead to ambiguous results, we prefer typing by denaturing polyacrylamide gel electrophoresis.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗

Effect on lipid metabolism of a biphasic desogestrel-containing oral contraceptive: divergent changes in apolipoprotein B and E and transitory decrease in Lp(a) levels.

The effect of a low dose biphasic oral contraceptive containing 40 micrograms ethinylestradiol + 25 micrograms desogestrel (7 tablets) and 30 micrograms ethinylestradiol + 125 micrograms desogestrel (15 tablets) on lipid metabolism was investigated in 19 women during 6 cycles of treatment and compared to the values of the pre- and post-treatment cycle. During treatment, all components of HDL increased reversibly by 10 to 30%. The levels of total cholesterol (CH), LDL-CH and IDL-CH rose only slightly, while those of total triglycerides (TG), VLDL-TG and LDL-TG rose continuously by more than 100% until the 6th cycle. At the same time, plasma levels of VLDL-CH increased by 60% and of apolipoprotein B by 20%. Contrary to this, apolipoprotein E decreased by 25% during treatment, and Lp(a) was transitorily reduced during the 3rd cycle. After termination of intake, total CH, LDL-CH, IDL-CH and apolipoprotein B remained elevated, while total TG, VLDL-TG, VLDL-CH and LDL-TG decreased significantly, but were still elevated during the post-treatment cycle. The levels of apolipoprotein E returned to pre-treatment values. The results indicate a marked preponderance of the effect of the estrogen component. The rise in TG and VLDL synthesis seems to be outweighed by an enhanced removal of apolipoprotein E-containing remnants which might offer protection from the development of atherosclerosis.

Adult↗

Type III hyperlipoproteinemia acquired by liver transplantation.

A case of type III hyperlipoproteinemia (HLP) (dysbetalipoproteinemia) acquired by liver transplantation is reported. The 50-year-old female patient was referred to the Frankfurt University Hospital for orthotopic liver transplantation. She had suffered from ethylic liver cirrhosis. The donor liver showed discrete signs of steatosis. The postoperative course of the patient was satisfactory. Enzyme levels and blood coagulation tests returned to normal within thirty days. However, both cholesterol and triglycerides gradually increased from approximately 2.00 g/L to values ranging from 2.50 to 3.50 g/L within 200 days after transplantation. Cutaneous xanthomas did not develop. The patient's lipoprotein pattern met the criteria of type III HLP: the cholesterol to triglyceride ratio in very low-density lipoproteins (VLDL) was 0.64. Intermediate-density lipoprotein(IDL) cholesterol was 0.48 g/L. Lipoprotein electrophoresis showed a broad beta-band, and beta-migrating particles were present in VLDL. Immunoblotting of apolipoprotein (apo) E from the patient's plasma revealed an E2/2 phenotype. However, restriction isotyping of an in vitro amplified apoE gene fragment showed the genotype of the patient to be epsilon 3/epsilon 4. These data suggest that the development of type III HLP in this patient was due to a change in the apoE phenotype from E3/4 to E2/2 after liver transplantation.

Apolipoproteins E↗

Serovar determination and molecular taxonomic correlation in Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum: a cooperative study of the International Working Group on Mycobacterial Taxonomy.

A cooperative study was conducted by the International Working Group on Mycobacterial Taxonomy to correlate the agglutination serovar designations of Mycobacterium avium, Mycobacterium intracellulare, and Mycobacterium scrofulaceum strains with the species ascriptions of these organisms according to molecular criteria and cultural properties and to assess the reproducibility of serovar determinations for a set of 63 reference strains of these species. Among the molecular criteria, the level of agreement between results obtained with nucleic acid probes and T-catalase serology results was 94% for strains of M. avium and M. intracellulare. Nucleic acid probes were not available for M. scrofulaceum, but none of the 10 strains ascribed to this species on the basis of catalase serology data reacted with a nucleic acid probe for M. avium or M. intracellulare. Ascription to a species on the basis of mycolic acid high-performance liquid chromatography patterns was in agreement with catalase serology results in 86% of the cases examined. Most strains belonging to serovars 1 through 6 and 8 through 11 were identified by molecular criteria as M. avium, most strains belonging to serovars 7, 12 through 20, 23, and 25 were identified as M. intracellulare, and most strains belonging to serovars 41 through 43 were identified as M. scrofulaceum, in agreement with common current practice. Evidence for assigning serovar 27 to M. scrofulaceum was obtained. However, two strains of a given serovar may, on occasion, be placed in different species. The dominant species assignments for strains belonging to serovars 21, 24, 26, and 28 remain unresolved.(ABSTRACT TRUNCATED AT 250 WORDS)

Agglutination Tests↗

Apolipoprotein E to B ratio: a marker for type III hyperlipoproteinaemia.

Apolipoproteins B and E were determined in 40 patients with type III hyperlipoproteinaemia (familial dysbetalipoproteinaemia) and in 48 patients with other types of hyperlipoproteinaemia matched for cholesterol and triacylglycerols. In type III patients, apolipoprotein E was increased and apolipoprotein B was lower than in other types of hyperlipoproteinaemia. The apolipoprotein E to apolipoprotein B ratio almost completely discriminated between type III and other types of hyperlipoproteinaemia. Assuming a cut-off value of 0.09 for the apolipoprotein E to apolipoprotein B ratio, diagnostic sensitivity was 95% and specificity was 88%. It is concluded that the apolipoprotein E to apolipoprotein B ratio represents the first-line screening quantity of choice for the identification of patients with type III hyperlipoproteinaemia in the clinical laboratory.

Adult↗

Determination of lipoprotein(a): evaluation of three methods.

Lipoprotein(a) (Lp(a)) is a strong independent risk factor for premature atherosclerosis. Structurally, Lp(a) closely resembles LDL. Its protein moiety contains apolipoprotein B-100 and apolipoprotein(a). We evaluated two commercial enzyme immunoassays (EIAs) and an immunoradiometric assay (IRMA) for Lp(a). The three assays differed in their design and they used different antibodies. In the immunoradiometric assay, two different monoclonal antibodies were used. In the first EIA, monoclonal anti-apolipoprotein(a) was bound to the solid phase and Lp(a) was detected with polyclonal anti-apolipoprotein B (Lp(a):B-EIA). In the second EIA, polyclonal anti-apolipoprotein(a) was used as capturing antibody and as detecting antibody (apo(a)-EIA). Ninety three plasma samples were assayed for Lp(a) with the three methods. The best correlation was obtained between the IRMA and the Lp(a):B-EIA (r = 0.971). Correlations between the apo(a)-EIA on the one hand and the IRMA or the Lp(a):B-EIA on the other hand were 0.889 and 0.836, respectively. The methods significantly differed in their calibration. This resulted in different mean Lp(a) concentrations. When tested against purified Lp(a), the apo(a)-EIA appeared accurately calibrated, whereas the IRMA and the Lp(a):B-EIA overestimated Lp(a) by approximately twofold. In the Lp(a):B-EIA, the detecting antibody is directed against apolipoprotein B. The Lp(a):B-EIA is, therefore, not affected by apolipoprotein(a) size polymorphism. This allows expression of the concentration of Lp(a):B complexes on a molar basis. In contrast, the polyclonal antibody-based apo(a)-EIA measures the concentration of apolipoprotein(a) antigen, and may, therefore, be susceptible to inter- and intra-individual polydispersity of apolipoprotein(a) and Lp(a) particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗

Fast lipoprotein chromatography: new method of analysis for plasma lipoproteins.

Fast lipoprotein chromatography (FLPC) is a novel method for quantifying lipoproteins. Plasma proteins are separated by fast-flow gel filtration. Lipoproteins are detected by post-column derivatization with an enzymatic cholesterol reagent. FLPC resolves very-low-, low-, and high-density lipoproteins (VLDL, LDL, and HDL, respectively) and completely separates apolipoprotein Al- and apolipoprotein B-containing lipoproteins. CVs for VLDL-cholesterol, LDL-cholesterol, and HDL-cholesterol are 5.8%, 2.0%, and 1.9%, respectively. We compared FLPC with a combined ultracentrifugation and precipitation method and obtained correlation of r = 0.979, 0.978, and 0.933 for VLDL-cholesterol, LDL-cholesterol, and HDL-cholesterol, respectively. Triglyceride concentrations up to 9.00 g/L did not interfere with the quantification of lipoproteins by FLPC. We conclude that FLPC is a precise and reliable method for the analysis of plasma lipoproteins that complements conventional techniques.

Apolipoprotein A-I↗

Amplification and direct sequencing of a cDNA encoding human cytosolic 3-hydroxy-3-methylglutaryl-coenzyme A synthase.

Cytosolic 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) synthase (E.C. 4.1.3.5) is a highly regulated enzyme involved in isoprenoid biosynthesis and therefore a potential target for cholesterol-lowering drugs. Up to now, primary structure data have only been available for chicken, rat and hamster HMG-CoA synthase. Using in vitro amplification and direct sequencing, we have determined the nucleotide sequence of the coding region of the human cytosolic 3-hydroxy-3-methylglutaryl CoA synthase cDNA.

Amino Acid Sequence↗