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M Simón

Publications and source records attributed to M Simón.

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Characterization of a porin from the outer membrane of Vibrio anguillarum.

The outer membranes of the 10 serovars of Vibrio anguillarum showed a common major protein with a size of around 40 kDa. Antibodies against the major outer membrane protein (MOMP) of V. anguillarum AO18 (serovar O1) cross-reacted with the MOMPs of all the other serovars but not with the outer membrane proteins of Escherichia coli. The MOMP of V. anguillarum serovar O1 was isolated, reconstituted to two-dimensional crystals, and structurally characterized by electron microscopy and image processing. The unit cell structure of the crystalline MOMP, as well as the secondary structure composition of the protein with a high amount of beta-structure, is strongly reminiscent of that of bacterial porins. The functional properties of the pores were investigated by conductance measurements with the MOMP reconstituted in planar lipid membranes. The V. anguillarum MOMP is characterized by a relatively weak cation selectivity and a moderate surface charge, and it shows voltage-dependent conductance effects. The MOMP is functionally similar to OmpF from E. coli, and it can be classified as a general diffusion porin.

Biological Transport

Biological variation in urine samples used for analyte measurements.

To determine the influence of biological variation on the reliability of data from different types of urine specimens, we measured nine analytes in first-morning, randomly collected, and 24-h samples of urine from 53 healthy individuals (14 men and 39 women). The urines were collected once a week for 10 weeks. The data obtained were used as a basis for specimen collection and to gain insight into the influence of urine quantities in the diagnosis, screening, and monitoring of patients. We found that 24-h urine expressed in output rather than concentration units is the most reliable specimen for diagnosis and monitoring for most of the analytes studied. On the basis of the ratio between estimated within- and between-subject variation, the tests with greatest medical usefulness for diagnosis and screening of specific pathologies are those measuring protein and sodium. Moreover, the results indicate that urine creatinine may be a poor test for diagnosis, monitoring, and screening.

Adult

[Transferability of results in hematologic determinations].

PURPOSE: To evaluate inaccuracy of the results attained in several Servei Catalá de la Salut laboratories in order to assess if quality purposes are accomplished and results are transferable between them. MATERIAL AND METHODS: Two types of haematological analysers are used: those based upon volumetric measurements and those using light dispersion for particle counting. Inaccuracy was ascertained in accordance to the inter-laboratory quality control programme. The inter-series study was performed with commercial control material in each laboratory with their own data, the monthly coefficient of variation being found, and the mean of the CV of 12 months was then calculated. Intra-series inaccuracy with commercial control material was assessed in each laboratory three times a day for 10 days, and the inaccuracy with fresh patient blood was examined daily in triplicate. The analytical inaccuracy attained in patient samples was also compared with that attained with stabilized control materials. RESULTS: The inaccuracy quality limits were exceeded in the haematological constituents under study. Quality objectives were accomplished in the inter-series inaccuracy study for red cell count, white cell count, MCV, granulocytes and lymphocytes. Repeat fresh patient-blood assays can be used to assess intra-series inaccuracy for red and white cell counts, but not for platelet count. CONCLUSIONS: Inaccuracy of the blood constituents studied is not transferable. Inaccuracy for the commonest haematological values is transferable between laboratories. Intra-series inaccuracy for red and white cell counts can be assessed by repeated use of fresh patient-blood when control material is not available. Patient samples are not advisable as a control of the white cell differential count for intra-series inaccuracy studies in those systems using volumetric principles.

Blood Cell Count

[Nabumetone].

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Adult