Pierre-Antoine Gourraud

Traditional cardiovascular risk factors in rheumatoid arthritis: a meta-analysis.

OBJECTIVEnRheumatoid arthritis is associated with increased cardiovascular morbidity and mortality. We performed a systematic review of the literature and a meta-analysis to look for differences in the prevalence of traditional cardiovascular risk factor between RA patients and controls.nnnMETHODSnMedline database was searched to identify studies evaluating the prevalence of traditional cardiovascular risk factors in rheumatoid arthritis patients and controls. Studies were selected and reviewed by two investigators. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated and pooled using a random-effects model. Statistical heterogeneity was evaluated through the use of Chi2 and I2 statistics.nnnRESULTSnFifteen case-control studies with a total of 2956 patients and 3713 controls met the inclusion criteria. The prevalence of smoking was increased in RA patients in comparison with controls: OR (95%CI) 1.56 (1.35-1.80) (P < 0.00001). The prevalence of hypertension did not differ: OR (95% CI) 1.09 (0.91-1.31) (P = 0.35). The prevalence of diabetes mellitus was increased in RA: OR (95%CI) 1.74 (1.22-2.50) (P = 0.003). The prevalence of hypercholesterolemia did not differ: OR (95%CI) 0.84 (0.67-1.04) (P = 0.11). HDL cholesterol levels were lower in RA patients: weighted mean difference -17.72 mg/dl (-18.35 - -17.08) (P < 0.00001). Significant heterogeneity among studies was found for diabetes mellitus and HDL cholesterol levels.nnnCONCLUSIONSnSome traditional cardiovascular risk factors, such as smoking, diabetes mellitus or lower HDL cholesterol levels, appear more prevalent in rheumatoid arthritis patients and could contribute to the increased cardiovascular morbidity and mortality observed in rheumatoid arthritis.

Handling missing values in population data: consequences for maximum likelihood estimation of haplotype frequencies

Haplotype frequency estimation in population data is an important problem in genetics and different methods including expectation maximisation (EM) methods have been proposed. The statistical properties of EM methods have been extensively assessed for data sets with no missing values. When numerous markers and/or individuals are tested, however, it is likely that some genotypes will be missing. Thus, it is of interest to investigate the behaviour of the method in the presence of incomplete genotype observations. We propose an extension of the EM method to handle missing genotypes, and we compare it with commonly used methods (such as ignoring individuals with incomplete genotype information or treating a missing allele as any other allele). Simulations were performed, starting from data sets of haematopoietic stem cell donors genotyped at three HLA loci. We deleted some data to create incomplete genotype observations in various proportions. We then compared the haplotype frequencies obtained on these incomplete data sets using the different methods to those obtained on the complete data. We found that the method proposed here provides better estimations, both qualitatively and quantitatively, but increases the computation time required. We discuss the influence of missing values on the algorithms efficiency and the advantages and disadvantages of deleting incomplete genotypes. We propose guidelines for missing data handling in routine analysis.

Galectin-1 is a powerful marker to distinguish chondroblastic osteosarcoma and conventional chondrosarcoma

The clinical management of osteosarcoma differs significantly from that of chondrosarcoma; therefore, it is extremely important to diagnose these 2 types of bone tumor accurately. In the absence of a specific marker, differential diagnosis by histochemistry is sometimes impossible, especially between chondroblastic osteosarcoma and conventional chondrosarcoma. We analyzed 165 bone sarcomas by immunohistochemical staining of tissue microarrays for expression of the galectin-1 (GAL1) lectin and by Western blot experiments. We found that GAL1 was abundant in normal human osteoblasts from benign proliferations and in osteosarcomas, including chondroblastic osteosarcomas, but not in chondrosarcomas. There was a highly significant statistical difference in the percentage of stained cells (P < 10(-4)) and in the staining intensity (P < 10(-3)) of chondroblastic osteosarcomas compared to conventional chondrosarcomas. This discriminatory potential of GAL1 staining for osteosarcoma-derived tumors was confirmed by Western blotting. We propose a diagnostic test for bone tumors that takes into account the optimal discriminative values for the percentage of cells stained and the intensity of staining. The positive and negative predictive values were 85.7% (trust interval of 63.7%-97%) and 90% (trust interval of 80%-95.9%), respectively, demonstrating the pertinence of the test. Altogether, our data indicate that GAL1 is a powerful diagnostic marker that distinguishes chondroblastic osteosarcomas from conventional chondrosarcomas.

IFIH1-GCA-KCNH7 locus is not associated with genetic susceptibility to multiple sclerosis in French patients.

A recent investigation reported, for the first time, an association between variants in the IFIH1-GCA-KCNH7 locus and multiple sclerosis (MS). We sought to replicate this genetic association in MS with a new independent MS cohort composed of French Caucasian MS trio families. The two most significant IFIH1 single nucleotide polymorphisms, rs1990760 and rs2068330, reported as involved in MS susceptibility, were genotyped in 591 French Caucasian MS trio families, and analyzed using the transmission/disequilibrium test. No association with MS was found (rs1990760, P=0.45 and rs2068330, P=0.27). Similarly, no significant association was detected after stratification for HLA-DRB1*1501 carriers. Reasons that may explain this discrepancy between the original report and our study are discussed.

Prevalence of Common Non-Hodgkin Lymphomas and Subtypes of Hodgkin Lymphoma by Nodal Site of Involvement: A Systematic Retrospective Review of 938 Cases.

Abstract Non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) represent a heterogeneous group of malignant lymphoid tumors, which have distinct histological and/or biological characteristics with preferential nodal involvement. However, none of the previous studies have assessed the prevalence of common NHL and HL subtypes at each nodal site of involvement. The aim of our study was to determine the prevalence of HL and NHL subtypes depending on their nodal sites of involvement. We conducted a single-center retrospective study of 938 lymphoma cases diagnosed in the Pathology Department of Toulouse Purpan Hospital in France between 2001 and 2008, taking into account the site that corresponded to the diagnostic biopsy. The most frequent sites were cervical lymph nodes (36.8% of all cases), inguinal lymph nodes (16.4%), axillary lymph nodes (11.9%), and supraclavicular lymph nodes (11%). We found an unexpected association between intraparotid nodes and nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and between inguinal nodes and follicular lymphoma. The risk of having classical Hodgkin lymphoma (CHL) was 15 times greater in patients with mediastinal lymphoma compared to those with other sites of involvement. Regarding HL, nodal and extranodal mediastinal sites and supraclavicular nodes were more likely to be involved by nodular sclerosis Hodgkin lymphoma (NSCHL). In addition, intra-abdominal lymph nodes were more frequently involved by lymphocyte depleted Hodgkin lymphoma compared to inguinal nodes where NLPHL predominated. Our study shows that some lymph node sites have a disproportionate prevalence of specific subtypes of lymphoma. Identifying these sites may aid to diagnose and better elucidate the pathogenesis of these tumors.

The validation of the sit-to-stand test for COPD patients

We read with interest the publication by Crook et al. [1] on the validation and responsive properties of the 1-min sit-to-stand (STS) test in patients with chronic obstructive pulmonary disease (COPD) undergoing pulmonary rehabilitation. The authors performed a comprehensive evaluation of the minimal clinical meaningful difference of the 1-min STS test. In our own dataset of patients from a multicentre study, this STS test exhibited similar level of reliability, intra-subject repeatability [2], and responsiveness to pulmonary rehabilitation with an estimated minimal important difference (MID) of three repetitions [3]. In their study, Crook et al. [1] emphasised the change in STS repetitions, which is better related to change in subjective outcomes (feeling thermometer notably), rather than with physical capacity outcomes such as the 6-min walk distance (6MWD). It is, after all, largely accepted that health-related quality of life (HRQoL) tools are the most sensitive in pulmonary rehabilitation, given the multimodal and patient-tailored interventions addressed in order to optimise benefits, not only focused on exercise training, but also on change in education and behaviour [4]. The change in the sit-to-stand test after a pulmonary rehabilitation is not influenced by the initial value http://ow.ly/i2CI30eqprD