Within-subject biological variation estimates using an indirect data mining strategy. Spanish multicenter pilot study (BiVaBiDa).

OBJECTIVES: The estimates of biological variation (BV) have traditionally been determined using direct methods, which present limitations. In response to this issue, two papers have been published addressing these limitations by employing indirect methods. Here, we present a new procedure, based on indirect methods that analyses data collected within a multicenter pilot study. Using this method, we obtain CVI estimates and calculate confidence intervals (CI), using the EFLM-BVD CVI estimates as gold standard for comparison. METHODS: Data were collected over a 18-month period for 7 measurands, from 3 Spanish hospitals; inclusion criteria: patients 18-75 years with more than two determinations. For each measurand, four different strategies were carried out based on the coefficient of variation ratio (rCoeV) and based on the use of the bootstrap method (OS1, RS2 and RS3). RS2 and RS3 use symmetry reference change value (RCV) to clean database. RESULTS: RS2 and RS3 had the best correlation for the CVI estimates with respect to EFLM-BVD. RS2 used the symmetric RCV value without eliminating outliers, while RS3 combined RCV and outliers. When using the rCoeV and OS1 strategies, an overestimation of the CVI value was obtained. CONCLUSIONS: Our study presents a new strategy for obtaining robust CVI estimates using an indirect method together with the value of symmetric RCV to select the target population. The CVI estimates obtained show a good correlation with those published in the EFLM-BVD database. Furthermore, our strategy can resolve some of the limitations encountered when using direct methods such as calculating confidence intervals.

La incorporación de reglas automatizadas asociadas a la calidad preanalítica de la muestra mejora la seguridad del paciente / The incorporation of automated rules associated with the pre-analytic quality of the sample improves patient safety

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Serum proteomic changes in adults with obstructive sleep apnoea.

To examine whether differentially expressed proteins are present in the serum of patients with obstructive sleep apnoea (OSA), iTRAQ techniques (isobaric tags for relative and absolute quantification) were employed in a prospective study. Individuals were assigned to either a non-OSA control group (apnoea-hypopnoea index, AHI <5) or an OSA group (AHI ≥5). Blood samples were collected, aliquoted and frozen at -80 °C. Protein digestion and tagging with iTRAQ4plex® and mass spectrometry analysis was then performed (MALDI TOF/TOF). Ten male subjects were included in the control group (age = 45 ± 9.7 years) and 30 male patients in the OSA group (age = 45 ± 10.7 years), the latter being then subdivided into three severity groups. A total of 103 proteins were identified with differential levels between patients with OSA and controls. Of these, 11 proteins were underexpressed and 19 were overexpressed in patients with OSA. C4BPA and thrombospondin were underexpressed in all three OSA severity groups. Among the overexpressed proteins, 13 were overexpressed in the mild OSA group, seven in the moderate group and five in the severe group. Analysis of interactions between the identified proteins revealed that protein alterations in OSA are primarily associated with derangements in lipid and vascular metabolic pathways. This study provides initial evidence that differential protein expression occurs in adults with OSA, and that such proteins change according to disease severity, and appear to primarily involve lipid and vascular metabolic pathways.

Variación de la expresión proteica en función de la gravedad del síndrome de apnea-hipopnea del sueño / Variation in Protein Expression Depending on the Severity of Sleep Apnoea-Hypopnoea Syndrome

ObjetivoEstudio prospectivo con muestreo consecutivo y grupo control para determinar si la expresión proteica en pacientes con SAHS es diferente a la de un grupo control (IAH ≤5).Pacientes y métodosFueron incluidos 32 pacientes, entre 35 y 60 años, a los que se les realizó una polisomnografía. Fueron excluidos los sujetos con enfermedad aguda o crónica. La primera dimensión del estudio proteómico se realizó en tiras IPG (18cm, pH 4–7) y, la segunda, en geles SDS-PAGE por triplicado para cada grupo. Los geles se tiñeron con SYPRO-Ruby (Bio-Rad®), se obtuvieron las imágenes con un escáner láser FX-Imager, y el análisis de los spots se realizó con el software ProteomWeaver v4.0 (Bio-Rad®). Se analizaron los cambios significativos entre los geles agrupados por réplicas y por separado, considerándose un cambio significativo si la intensidad relativa en los spots fue superior o inferior en 3 veces a la del control y se observó en 2 de las 3 réplicas de cada grupo con un coeficiente de variación <20%.ResultadosLos pacientes fueron divididos en 8 sujetos por grupo (control, leve, moderado y grave). La comparación de los geles constató diferencias significativas entre el grupo control y los 3 grupos clínicos, observándose 3 spots con sobreexpresión significativa y 7 spots subexpresados respecto al grupo control.ConclusiónExisten cambios significativos en la expresión protéica entre un grupo control y pacientes en distintos estadios de enfermedad. El estudio proteómico puede identificar biomarcadores relacionados con el diagnóstico y gravedad del SAHS(AU)

ObjectiveA prospective study with a consecutive sample and a control group to determine whether protein expression in patients with sleep apnoea-hypopnoea syndrome (SAHS) is different from that of the control group (IAH ≤5).Patients and methodsA total of 32 patients aged between 35 and 60 years who had a polysomnograph performed were included. Patients with an acute or chronic were excluded. The first dimension of the proteomic study was carried out on IPG strips (18cm, pH 4–7) and the second on SDS-PAGE gels in triplicate for each group. The gels were stained with SYPRO-Ruby (Bio-Rad®), the images obtained with an FX-Imager laser scanner and the spots were analysed using ProteomWeaver v. 4.0 (Bio-Rad®) software. Significant changes between the gels were analysed by replicates and separately, being considered a significant change if the relative intensity of the spots was three times higher or lower than that of the control and if it was observed in 2 of the 3 replicates of each group, with a coefficient of variation of <20%.ResultsThe patients were divided into 8 subjects per group (control, mild, moderate and severe). The comparison of the gels showed significant differences between the control group and the 3 clinical groups, with significant over-expression being observed in 3 spots, and under-expression in 7 spots in the control group.ConclusionThere are significant changes in protein expression between a control group and patients in different stages of disease. The proteomic study can identify biomarkers associated with the diagnosis and severity of the SAHS(AU)

[Variation in protein expression depending on the severity of sleep apnoea-hypopnoea syndrome]. / Variación de la expresión proteica en función de la gravedad del síndrome de apnea-hipopnea del sueño.

OBJECTIVE: A prospective study with a consecutive sample and a control group to determine whether protein expression in patients with sleep apnoea-hypopnoea syndrome (SAHS) is different from that of the control group (IAH < or =5). PATIENTS AND METHODS: A total of 32 patients aged between 35 and 60 years who had a polysomnograph performed were included. Patients with an acute or chronic were excluded. The first dimension of the proteomic study was carried out on IPG strips (18cm, pH 4-7) and the second on SDS-PAGE gels in triplicate for each group. The gels were stained with SYPRO-Ruby (Bio-Rad((R))), the images obtained with an FX-Imager laser scanner and the spots were analysed using ProteomWeaver v. 4.0 (Bio-Rad((R))) software. Significant changes between the gels were analysed by replicates and separately, being considered a significant change if the relative intensity of the spots was three times higher or lower than that of the control and if it was observed in 2 of the 3 replicates of each group, with a coefficient of variation of <20%. RESULTS: The patients were divided into 8 subjects per group (control, mild, moderate and severe). The comparison of the gels showed significant differences between the control group and the 3 clinical groups, with significant over-expression being observed in 3 spots, and under-expression in 7 spots in the control group. CONCLUSION: There are significant changes in protein expression between a control group and patients in different stages of disease. The proteomic study can identify biomarkers associated with the diagnosis and severity of the SAHS.