Prospective phase II trial of extended treatment with rituximab in patients with B-cell post-transplant lymphoproliferative disease.

BACKGROUND AND OBJECTIVES The elective treatment of patients with post-transplant lymphoproliferative disorders is controversial. The purpose of this trial was to evaluate the efficacy of treatment with extended doses of rituximab adapted to the response in patients with post-transplant lymphoproliferative disorders after solid organ transplantation. DESIGN AND METHODS This was a prospective, multicenter, phase II trial. Patients were treated with reduction of immunosuppression and four weekly infusions of rituximab. Those patients who did not achieve complete remission (CR) received a second course of four rituximab infusions. The primary end-point of the study was the CR rate. RESULTS Thirty-eight patients were assesable. One episode of grade 4 neutropenia was the only severe adverse event observed. After the first course of rituximab, 13 (34.2%) patients achieved CR, 8 patients did not respond, and 17 patients achieved partial remission. Among those 17 patients, 12 could be treated with a second course of rituximab, and 10 (83.3%) achieved CR, yielding an intention-to-treat CR rate of 60.5%. Eight patients excluded from the trial because of absence of CR were treated with rituximab combined with chemotherapy, and six (75%) achieved CR. Event-free survival was 42% and overall survival was 47% at 27.5 months. Fourteen patients died, ten of progression of their post-transplant lymphoproliferative disorder. INTERPRETATION AND CONCLUSIONS These results confirm that extended treatment with rituximab can obtain a high rate of CR in patients with post-transplant lymphoproliferative disorders after solid organ transplantation without increasing toxicity, and should be recommended as initial therapy for these patients.

Trends in yearly prevalence of third-generation cephalosporin and fluoroquinolone resistant Enterobacteriaceae infections and antimicrobial use in Spanish hospitals, Spain, 1999 to 2010.

Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp. are a major cause of infections in hospitalised patients. The aim of our study was to evaluate rates and trends of resistance to third-generation cephalosporins and fluoroquinolones in infected patients, the trends in use for these antimicrobials, and to assess the potential correlation between both trends. The database of national point prevalence study series of infections and antimicrobial use among patients hospitalised in Spain over the period from 1999 to 2010 was analysed. On average 265 hospitals and 60,000 patients were surveyed per year yielding a total of 19,801 E. coli, 3,004 K. pneumoniae and 3,205 Enterobacter isolates. During the twelve years period, we observed significant increases for the use of fluoroquinolones (5.8%-10.2%, p<0.001), but not for third-generation cephalosporins (6.4%-5.9%, p=NS). Resistance to third-generation cephalosporins increased significantly for E. coli (5%-15%, p<0.01) and for K. pneumoniae infections (4%-21%, p<0.01) but not for Enterobacter spp. (24%). Resistance to fluoroquinolones increased significantly for E. coli (16%30%, p<0.01), for K. pneumoniae (5%-22%, p<0.01), and for Enterobacter spp. (6%-15%, p<0.01). We found strong correlations between the rate of fluoroquinolone use and the resistance to fluoroquinolones, third-generation cephalosporins, or co-resistance to both, for E. coli (R=0.97, p<0.01, R=0.94, p<0.01, and R=0.96, p<0.01, respectively), and for K. pneumoniae (R=0.92, p<0.01, R=0.91, p<0.01, and R=0.92, p<0.01, respectively). No correlation could be found between the use of third-generation cephalosporins and resistance to any of the latter antimicrobials. No significant correlations could be found for Enterobacter spp.. Knowledge of the trends in antimicrobial resistance and use of antimicrobials in the hospitalised population at the national level can help to develop prevention strategies.

Effective diagnosis of Alzheimer's disease by means of large margin-based methodology.

BACKGROUND Functional brain images such as Single-Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) have been widely used to guide the clinicians in the Alzheimer's Disease (AD) diagnosis. However, the subjectivity involved in their evaluation has favoured the development of Computer Aided Diagnosis (CAD) Systems. METHODS It is proposed a novel combination of feature extraction techniques to improve the diagnosis of AD. Firstly, Regions of Interest (ROIs) are selected by means of a t-test carried out on 3D Normalised Mean Square Error (NMSE) features restricted to be located within a predefined brain activation mask. In order to address the small sample-size problem, the dimension of the feature space was further reduced by: Large Margin Nearest Neighbours using a rectangular matrix (LMNN-RECT), Principal Component Analysis (PCA) or Partial Least Squares (PLS) (the two latter also analysed with a LMNN transformation). Regarding the classifiers, kernel Support Vector Machines (SVMs) and LMNN using Euclidean, Mahalanobis and Energy-based metrics were compared. RESULTS Several experiments were conducted in order to evaluate the proposed LMNN-based feature extraction algorithms and its benefits as: i) linear transformation of the PLS or PCA reduced data, ii) feature reduction technique, and iii) classifier (with Euclidean, Mahalanobis or Energy-based methodology). The system was evaluated by means of k-fold cross-validation yielding accuracy, sensitivity and specificity values of 92.78%, 91.07% and 95.12% (for SPECT) and 90.67%, 88% and 93.33% (for PET), respectively, when a NMSE-PLS-LMNN feature extraction method was used in combination with a SVM classifier, thus outperforming recently reported baseline methods. CONCLUSIONS All the proposed methods turned out to be a valid solution for the presented problem. One of the advances is the robustness of the LMNN algorithm that not only provides higher separation rate between the classes but it also makes (in combination with NMSE and PLS) this rate variation more stable. In addition, their generalization ability is another advance since several experiments were performed on two image modalities (SPECT and PET).