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Biomedical subjects

J Eugui

Publications and source records attributed to J Eugui.

16 recordsLinked to original sources
PubMed1994

Immunoturbidimetry of serum apolipoproteins A-I and B on the Cobas Bio centrifugal analyzer: method validation and reference values.

We describe an immunoturbidimetric assay for estimating the concentration of apolipoproteins (apo) A-I and B in serum with a Cobas Bio centrifugal analyzer. Several analytical variables were studied: pH, temperature, wavelength, reaction time, sample pretreatment, antisera dilution, concentration of NaCl, phosphate buffer, and PEG 6000; a good optical response was obtained with small volumes of sample and antisera. Imprecision was low, with intrarun coefficient of variance (CV) from 1.1 to 2.8% and interrun CV from 1.8 to 3.2%. We demonstrated a good correlation between our method and radial immunodiffusion for apo A-I (r = 0.975) and apo B (r = 0.980). Reference values were calculated from a sample of 494 healthy subjects, and separate intervals for the ratio of apo A-I to apo B in gender and age subgroups were established.

Adult↗
PubMed1991

Multicenter evaluation of new enzyme-linked immunoassays of follitropin and lutropin in serum or plasma.

Results from a multicenter evaluation of two new enzyme-linked immunosorbent assays [Enzymun-Test for follitropin (FSH) and lutropin (LH)] are presented and compared with results from 11 other commercial immunoassays, radioactive as well as nonradioactive. Enzymun-Test FSH and LH assays are suitable for automated systems and manual applications. The tests were reproducible (CV less than 5%), highly specific, and sensitive enough (less than 0.5 int. unit/L) to measure the hormones directly in almost all patients' samples, except for LH measurements in prepubertal children. We did not find interference by heterophilic antibodies or other factors. A comparison of assays for FSH found very good agreement among all modern two-site assays; competitive immunoassays almost invariably yielded systematically lower results for FSH, probably because of the heterogeneity of the International Reference Preparation (2nd IRP FSH, 78/549). For LH also we found good agreement, with no systematic differences among the various reagents. Guidelines for reference values with the new reagents are given.

Adult↗
PubMed1989

Evaluation of two new automated enzymoimmunometric assays for serum follitropin and lutropin.

Two new enzymoimmunoassays for FSH and LH adapted to the ES 600 analyzer (Boehringer Mannheim Diagnostics) were evaluated. The limit of detection was below 0.5 mIU/ml. Precision was excellent, the intra-assay coefficients of variation ranged from 1.2 to 2.2%, and the interassay variations from 2.0 to 2.8%. Both methods compared well with other commercial enzyme immunoassays, with correlation coefficients for FSH and LH of 0.988 and 0.974, respectively. There was no interference on the assays by the rheumatoid factor. The results of an external quality control assured the reliability of the measurements. Preliminary reference values were obtained.

Adult↗
PubMed1983

Rapid turbidimetric determination of serum C3c and C4 by end point centrifugal analysis.

An end point turbidimetric method for the determination of C3c and C4 in serum using a centrifugal analyzer (Cobas Bio) is described. Several analytical factors were evaluated -pH, temperature, PEG and antibody concentration. Wide variations of temperature and pH did not significantly affect the turbidimetric reaction. A 20 g/L PEG concentration and 25-fold antiserum dilution were found satisfactory for the analysis. Precision of the assay was good and comparison with a RID method yielded an r value of 0.97. The procedure is simple and reliable.

Centrifugation↗
PubMed1977

NADH-cytochrome c reductase, succinate cytochrome c reductase and phospholipids.

Phospholipid peroxidation of isolated rat liver inner mitochondrial membranes induced by either ascorbate or cysteine was accompanied by a release of flavins and coenzyme Q. A straight correlation between this release and the alteration of molecular species of phosphatidylcholine and phosphatidylethanolamine containing one saturated and one unsaturated fatty acid has been found. Peroxidation induced on molecular species of phosphatidylcholine and phosphatidylethanolamine containing only unsaturated fatty acids were accompanied by losses in enzyme activities of NADH-cytochrome c reductase and succinate cytochrome c reductase.

Animals↗
PubMed1977

Protein distribution is submitochondrial particles after lipid peroxidation.

Three fractions of submitochondrial particles were isolated by differential centrifugation of mitochondrial inner membranes incubated with 1 mM ascorbate. Proteins were separated by polyacrylamide gel electrophoresis and their pattern was found to be different for the three fractions. These results are in agreement with previous work which showed the dissimilar enzyme distribution and chemical composition of these submitochondrial particles and pointed out the heterogeneity of the inner mitochondrial membrane.

Animals↗
PubMedDate not supplied

[Distribution of proteins and enzymes in 3 submitochondrial fractions isolated from the internal mitochondrial membrane of the rat liver].

Three fractions, A, B and C, were separated from rat liver inner mitochondrial membranes by sonication and centrifugation on a discontinuous sucrose gradient, and their distribution of enzyme activities, cytochromes and proteins was studied, in order to obtain data about the heterogeneous composition of the inner membrane. Fraction C was mitochondrial matrix. It contained about 90% of glutamate dehydrogenase activity, and its protein distribution in polyacrylamide gels was similar to that of mitochondrial matrix. Fraction B, with nearly 85% of enzyme activities and cytochrome contents of control inner membranes, would correspond to the crista membrane. Only 4% of cytochromes and enzyme activities of the inner membrane were found in fraction A, which would be the inner peripheral membrane, in contact with the outer membrane.

Animals↗