Assessment of a dried blood spot C-reactive protein method to identify disease flares in rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is characterised by painful, stiff and swollen joints. RA features sporadic 'flares' or inflammatory episodes-mostly occurring outside clinics-where symptoms worsen and plasma C-reactive protein (CRP) becomes elevated. Poor control of inflammation results in higher rates of irreversible joint damage, increased disability, and poorer quality of life. Flares need to be accurately identified and managed. A method comparison study was designed to assess agreement between CRP values obtained by dried blood spot (DBS) versus conventional venepuncture sampling. The ability of a weekly DBS sampling and CRP test regime to detect flare outside the clinic was also assessed. Matched venepuncture and finger lancet DBS samples were collected from n = 100 RA patients with active disease at baseline and 6 weeks (NCT02809547). A subset of n = 30 RA patients submitted weekly DBS samples over the study period. Patient demographics, including self-reported flares were recorded. DBS sample CRP measurements were made by enzyme-linked immunosorbent assay, and venepuncture samples by a reference immunoturbometric assay. Data was compared between sample types by Bland-Altman and weighted Deming regression analyses. Flare detection sensitivity and specificity were compared between 'minimal' baseline and 6 week sample CRP data and the 'continuous' weekly CRP data. Baseline DBS ELISA assay CRP measures yielded a mean positive bias of 2.693 ± 8.640 (95% limits of agreement - 14.24 to 19.63%), when compared to reference assay data. Deming regression revealed good agreement between the DBS ELISA method and reference assay data, with baseline data slope of 0.978 and intercept -0.153. The specificity of 'continuous' area under the curve (AUC) CRP data (72.7%) to identify flares, was greater than 'minimal' AUC CRP data (54.5%). This study indicates reasonable agreement between DBS and the reference method, especially at low to mid-range CRP values. Importantly, longitudinal CRP measurement in RA patients helps to clearly identify flare and thus could assist in remote monitoring strategies and may facilitate timely therapeutic intervention.Trial registration: The Remote Arthritis Disease Activity MonitoR (RADAR) study was registered on 22/06/2016 at ClinicalTrials.gov Identifier: NCT02809547. https://clinicaltrials.gov/ct2/show/NCT02809547 .

Imaging predictors for assessment of inferior vena cava wall invasion in patients with renal cell carcinoma and inferior vena cava tumor thrombus: a retrospective study.

BACKGROUND: Renal cell carcinoma (RCC) has the propensity to lead to venous tumor thrombus (VTT). Nephrectomy with tumor thrombectomy is an effective treatment option but is a technically challenging surgical procedure that is accompanied by a high rate of complications. The aims of this study were to investigate pre-operative imaging parameters for the assessment of inferior vena cava (IVC) wall invasion due to a tumor thrombus in patients with RCC and to identify predictors from the intra-operative findings. METHODS: Clinical and imaging data were collected from 110 patients who underwent nephrectomy with IVC tumor thrombectomy (levels I-IV) for RCC and IVC tumor thrombus at the Peking University Third Hospital between May 2015 and March 2018. Univariable and multivariable logistic regression and receiver operating characteristic curves were used to assess the correlations between pre-operative imaging features and intra-operative macroscopic invasions of the IVC wall by tumor thrombus. RESULTS: Among the 110 patients, 41 underwent partial or segmental resection of IVC. There were univariate associations of pre-operative imaging parameters that could be used to predict the need for IVC resection, including those of the Mayo classification, maximum anterior-posterior (AP) diameter of the renal vein at the renal vein ostium (RVo), maximum AP diameter of the VTT at the RVo and IVC occlusion. For the multivariable analysis, the AP diameter of the VTT at the RVo and IVC occlusion were associated with a significantly increased risk of invasion of the IVC wall by tumor thrombus. The optimum imaging thresholds included an AP diameter of the VTT at the RVo larger than 17.0 mm and the presence of IVC occlusion, with which we predicted invasions of the IVC wall requiring IVC resection. The probabilities of intra-operative IVC resection for patients without both independent factors, with an AP diameter of the VTT at the RVo larger than 17.0 mm, with IVC occlusion, and with both concurrent factors were 5%, 23%, 56%, and 66%, respectively. CONCLUSION: An increase in the AP VTT diameter at the RVo and the presence of complete occlusion of the IVC are independent risk factors for a high probability of IVC wall invasion by tumor thrombus.

Novel genomic methods for drug discovery and mechanism-based toxicological assessment.

Genomics encompasses a range of powerful technologies that can be applied at all levels of gene expression, from transcription to mRNA translation. Collectively, these technologies have great potential for improving drug discovery, both target and molecule recognition, and development. In this article we review the current and potential future status of established and novel genomic methods within drug discovery.

Effect of pooling samples on the efficiency of comparative studies using microarrays.

MOTIVATION: Many biomedical experiments are carried out by pooling individual biological samples. However, pooling samples can potentially hide biological variance and give false confidence concerning the data significance. In the context of microarray experiments for detecting differentially expressed genes, recent publications have addressed the problem of the efficiency of sample pooling, and some approximate formulas were provided for the power and sample size calculations. It is desirable to have exact formulas for these calculations and have the approximate results checked against the exact ones. We show that the difference between the approximate and the exact results can be large. RESULTS: In this study, we have characterized quantitatively the effect of pooling samples on the efficiency of microarray experiments for the detection of differential gene expression between two classes. We present exact formulas for calculating the power of microarray experimental designs involving sample pooling and technical replications. The formulas can be used to determine the total number of arrays and biological subjects required in an experiment to achieve the desired power at a given significance level. The conditions under which pooled design becomes preferable to non-pooled design can then be derived given the unit cost associated with a microarray and that with a biological subject. This paper thus serves to provide guidance on sample pooling and cost-effectiveness. The formulation in this paper is outlined in the context of performing microarray comparative studies, but its applicability is not limited to microarray experiments. It is also applicable to a wide range of biomedical comparative studies where sample pooling may be involved.