Learning spatial filters for multispectral image segmentation

We present a novel filtering method for multispectral satellite image classification. The proposed method learns a set of spatial filters that maximize class separability of binary support vector machine (SVM) through a gradient descent approach. Regularization issues are discussed in detail and a Frobenius-norm regularization is proposed to efficiently exclude uninformative filters coefficients. Experiments carried out on multiclass one-against-all classification and target detection show the capabilities of the learned spatial filters.

Late removal of retrievable caval filters.

The advent of retrievable caval filters was a game changer in the sense, that the previously irreversible act of implanting a medical device into the main venous blood stream of the body requiring careful evaluation of the pros and cons prior to execution suddenly became a "reversible" procedure where potential hazards in the late future of the patient lost most of their weight at the time of decision making. This review was designed to assess the rate of success with late retrieval of so called retrievable caval filters in order to get some indication about reasonable implant duration with respect to relatively "easy" implant removal with conventional means, i.e., catheters, hooks and lassos. A PubMed search (www.pubmed.gov) was performed with the search term "cava filter retrieval after 30 days clinical", and 20 reports between 1994 and 2013 dealing with late retrieval of caval filters were identified, covering approximately 7,000 devices with 600 removed filters. The maximal duration of implant reported is 2,599 days and the maximal implant duration of removed filters is also 2,599 days. The maximal duration reported with standard retrieval techniques, i.e., catheter, hook and/or lasso, is 475 days, whereas for the retrievals after this period more sophisticated techniques including lasers, etc. were required. The maximal implant duration for series with 100% retrieval accounts for 84 days, which is equivalent to 12 weeks or almost 3 months. We conclude that retrievable caval filters often become permanent despite the initial decision of temporary use. However, such "forgotten" retrievable devices can still be removed with a great chance of success up to three months after implantation. Conventional percutaneous removal techniques may be sufficient up to sixteen months after implantation whereas more sophisticated catheter techniques have been shown to be successful up to 83 months or more than seven years of implant duration. Tilting, migrating, or misplaced devices should be removed early on, and replaced if indicated with a device which is both, efficient and retrievable.

Hypotensive effect of human factor XII active fragment in conscious normotensive rats: role of bradykinin.

The active fragment derived from factor XII (factor XIIf) was purified from human plasma and administered intravenously to normotensive conscious rats. Factor XIIf-mediated hypotension was dose-dependent and augmented by pretreatment with captopril, an inhibitor of the bradykinin-processing enzyme kininase II. These results therefore suggest that factor XIIf-mediated hypotension is due to the formation of bradykinin.

Orthotropic active strain models for the numerical simulation of cardiac biomechanics

An active strain formulation for orthotropic constitutive laws arising in cardiac mechanics modeling is introduced and studied. The passive mechanical properties of the tissue are described by the Holzapfel-Ogden relation. In the active strain formulation, the Euler-Lagrange equations for minimizing the total energy are written in terms of active and passive deformation factors, where the active part is assumed to depend, at the cell level, on the electrodynamics and on the specific orientation of the cardiac cells. The well-posedness of the linear system derived from a generic Newton iteration of the original problem is analyzed and different mechanical activation functions are considered. In addition, the active strain formulation is compared with the classical active stress formulation from both numerical and modeling perspectives. Taylor-Hood and MINI finite elements are employed to discretize the mechanical problem. The results of several numerical experiments show that the proposed formulation is mathematically consistent and is able to represent the main key features of the phenomenon, while allowing savings in computational costs.

Intracellular nanomanipulation by a photonic-force microscope with real-time acquisition of a 3D stiffness matrix.

A traditional photonic-force microscope (PFM) results in huge sets of data, which requires tedious numerical analysis. In this paper, we propose instead an analog signal processor to attain real-time capabilities while retaining the richness of the traditional PFM data. Our system is devoted to intracellular measurements and is fully interactive through the use of a haptic joystick. Using our specialized analog hardware along with a dedicated algorithm, we can extract the full 3D stiffness matrix of the optical trap in real time, including the off-diagonal cross-terms. Our system is also capable of simultaneously recording data for subsequent offline analysis. This allows us to check that a good correlation exists between the classical analysis of stiffness and our real-time measurements. We monitor the PFM beads using an optical microscope. The force-feedback mechanism of the haptic joystick helps us in interactively guiding the bead inside living cells and collecting information from its (possibly anisotropic) environment. The instantaneous stiffness measurements are also displayed in real time on a graphical user interface. The whole system has been built and is operational; here we present early results that confirm the consistency of the real-time measurements with offline computations.

Beta(1)-selective agonist (-)-1-(3,4-dimethoxyphenetylamino)-3-(3,4-dihydroxy)-2-propanol [(-)-RO363] differentially interacts with key amino acids responsible for beta(1)-selective binding in resting and active states.

(-)-1-(3,4-Dimethoxyphenetylamino)-3-(3,4-dihydroxy)-2-propanol [(-)-RO363] is a highly selective beta(1)-adrenergic receptor (beta(1)AR) agonist. To study the binding site of beta(1)-selective agonist, chimeric beta(1)/beta(2)ARs and Ala-substituted beta(1)ARs were constructed. Several key residues of beta(1)AR [Leu(110) and Thr(117) in transmembrane domain (TMD) 2], and Phe(359) in TMD 7] were found to be responsible for beta(1)-selective binding of (-)-RO363, as determined by competitive binding. Based on these results, we built a three-dimensional model of the binding domain for (-)-RO363. The model indicated that TMD 2 and TMD 7 of beta(1)AR form a binding pocket; the methoxyphenyl group of N-substituent of (-)-RO363 seems to locate within the cavity surrounded by Leu(110), Thr(117), and Phe(359). The amino acids Leu(110) and Phe(359) interact with the phenyl ring of (-)-RO363, whereas Thr(117) forms hydrogen bond with the methoxy group of (-)-RO363. To examine the interaction of these residues with beta(1)AR in an active state, each of the amino acids was changed to Ala in a constitutively active (CA)-beta(1)AR mutant. The degree of decrease in the affinity of CA-beta(1)AR for (-)-RO363 was essentially the same as that of wild-type beta(1)AR when mutated at Leu(110) and Thr(117). However, the affinity was decreased in Ala-substituted mutant of Phe(359) compared with that of wild-type beta(1)AR. These results indicated that Leu(110) and Thr(117) are necessary for the initial binding of (-)-RO363 with beta(1)-selectivity, and interaction of Phe(359) with the N-substituent of (-)-RO363 in an active state is stronger than in the resting state.

BAL9141, a novel extended-spectrum cephalosporin active against methicillin-resistant Staphylococcus aureus in treatment of experimental endocarditis.

The therapeutic efficacy of BAL9141 (formerly Ro 63-9141), a novel cephalosporin with broad in vitro activity that also has activity against methicillin-resistant Staphylococcus aureus (MRSA), was investigated in rats with experimental endocarditis. The test organisms were homogeneously methicillin-resistant S. aureus strain COL transformed with the penicillinase-encoding plasmid pI524 (COL Bla+) and homogeneously methicillin-resistant, penicillinase-producing isolate P8-Hom, selected by serial exposure of parent strain P8 to methicillin. The MICs of BAL9141 for these organisms (2 mg/liter) were low, and BAL9141was bactericidal in time-kill curve studies after 24 h of exposure to either two, four, or eight times the MIC. Rats with experimental endocarditis were treated in a three-arm study with a continuous infusion of BAL5788 (formerly Ro 65-5788), a carbamate prodrug of BAL9141, or with amoxicillin-clavulanate or vancomycin. The rats were administered BAL9141 to obtain steady-state target levels of 20, 10, and 5 mg of per liter or were administered either 1.2 g of amoxicillin-clavulanate (ratio 5:1) every 6 h or 1 g of vancomycin every 12 h at changing flow rates to simulate the pharmacokinetics produced in humans by intermittent intravenous treatment. Treatment was started 12 h after bacterial challenge and lasted for 3 days. BAL9141 was successful in the treatment of experimental endocarditis due to either MRSA isolate COL Bla+ or MRSA isolate P8-Hom at the three targeted steady-state concentrations and sterilized >90% of cardiac vegetations (P < 0.005 versus controls; P < 0.05 versus amoxicillin-clavulanate and vancomycin treatment groups). These promising in vivo results with BAL9141 correlated with the high affinity of the drug for PBP 2a and its stability to penicillinase hydrolysis observed in vitro.

La surveillance active dans la prise en charge du cancer de la prostate précoce. [Active surveillance for early-stage prostate cancer]

Diagnostic and treatment management of prostate cancer at its initial stage continues to raise important debates within the involved medical community. To establish a protocol for active surveillance, a validated option in specific conditions of localised prostate cancer management for eight years, is a unique opportunity to gather different specialists in this field. This paper presents this concept.

Cancer risk in the Swiss HIV Cohort Study: associations with immunodeficiency, smoking, and highly active antiretroviral therapy.

BACKGROUND: Persons infected with human immunodeficiency virus (HIV) have an increased risk for several cancers, but the influences of behavioral risk factors, such as smoking and intravenous drug use, and highly active antiretroviral therapy (HAART) on cancer risk are not clear. METHODS: Patient records were linked between the Swiss HIV Cohort Study and Swiss cantonal cancer registries. Observed and expected numbers of incident cancers were assessed in 7304 persons infected with HIV followed for 28,836 person-years. Relative risks for cancer compared with those for the general population were determined by estimating cancer registry-, sex-, age-, and period-standardized incidence ratios (SIRs). RESULTS: Highly elevated SIRs were confirmed in persons infected with HIV for Kaposi sarcoma (KS) (SIR = 192, 95% confidence interval [CI] = 170 to 217) and non-Hodgkin lymphoma (SIR = 76.4, 95% CI = 66.5 to 87.4). Statistically significantly elevated SIRs were also observed for anal cancer (SIR = 33.4, 95% CI = 10.5 to 78.6); Hodgkin lymphoma (SIR = 17.3, 95% CI = 10.2 to 27.4); cancers of the cervix (SIR = 8.0, 95% CI = 2.9 to 17.4); liver (SIR = 7.0, 95% CI = 2.2 to 16.5); lip, mouth, and pharynx (SIR = 4.1, 95% CI = 2.1 to 7.4); trachea, lung, and bronchus (SIR = 3.2, 95% CI = 1.7 to 5.4); and skin, nonmelanomatous (SIR = 3.2, 95% CI = 2.2 to 4.5). In HAART users, SIRs for KS (SIR = 25.3, 95% CI = 10.8 to 50.1) and non-Hodgkin lymphoma (SIR = 24.2, 95% CI = 15.0 to 37.1) were lower than those for nonusers (KS SIR = 239, 95% CI = 211 to 270; non-Hodgkin lymphoma SIR = 99.3, 95% CI = 85.8 to 114). Among HAART users, however, the SIR (although not absolute numbers) for Hodgkin lymphoma (SIR = 36.2, 95% CI = 16.4 to 68.9) was comparable to that for KS and non-Hodgkin lymphoma. No clear impact of HAART on SIRs emerged for cervical cancer or non-acquired immunodeficiency syndrome-defining cancers. Cancers of the lung, lip, mouth, or pharynx were not observed among nonsmokers. CONCLUSION: In persons infected with HIV, HAART use may prevent most excess risk of KS and non-Hodgkin lymphoma, but not that of Hodgkin lymphoma and other non-acquired immunodeficiency syndrome-defining cancers. No cancers of the lip, mouth, pharynx, or lung were observed in nonsmokers.

Active intravenous drug use during chronic hepatitis C therapy does not reduce sustained virological response rates in adherent patients.

SUMMARY: Reluctance has been expressed about treating chronic hepatitis C in active intravenous (IV) drug users (IDUs), and this is found in both international guidelines and routine clinical practice. However, the medical literature provides no evidence for an unequivocal treatment deferral of this risk group. We retrospectively analyzed the direct effect of IV drug use on treatment outcome in 500 chronic hepatitis C patients enrolled in the Swiss Hepatitis C Cohort Study. Patients were eligible for the study if they had their serum hepatitis C virus (HCV) RNA tested 6 months after the end of treatment and at least one visit during the antiviral therapy, documenting the drug use status. Five hundred patients fulfilled the inclusion criteria (199 were IDU and 301 controls). A minimum exposure to 80% of the scheduled cumulative dose of antivirals was reached in 66.0% of IDU and 60.5% of controls (P = NS). The overall sustained virological response (SVR) rate was 63.6%. Active IDU reached a SVR of 69.3%, statistically not significantly different from controls (59.8%). A multivariate analysis for treatment success showed no significant negative influence of active IV drug use. In conclusion, our study shows no relevant direct influence of IV drugs on the efficacy of anti-HCV therapy among adherent patients.

Comparison of [3H]tamsulosin and [3H]prazosin binding to wild-type and constitutively active alpha1B-adrenoceptors.

We have tested the hypothesis that smaller alpha1B-adrenoceptor labeling by [3H]tamsulosin compared to [3H]prazosin is related to differential recognition of agonist low affinity states. Paired saturation binding experiments with [3H]prazosin and [3H]tamsulosin were performed in membrane preparations from rat liver and Rat- fibroblasts stably transfected with wild-type hamster alpha1B-adrenoceptors or a constitutively active mutant thereof. In all three settings [3H]tamsulosin labeled significantly fewer alpha1B-adrenoceptors than [3H]prazosin. In noradrenaline competition binding experiments, the percentage of agonist low affinity sites was smallest for the constitutively active alpha1B-adrenoceptor but the percentage of agonist low affinity sites recognized by [3H]tamsulosin and [3H]prazosin did not differ significantly. We conclude that [3H]tamsulosin labels fewer alpha1B-adrenoceptors than [3H]prazosin but this is not fully explained by a poorer labeling of agonist low affinity sites.

Health education of diabetes as a chronic disease : transmission of information or active appropriation ?

Résumé du poster : Diabetes is both an important chronic disease and a real public health problem. It requires a great control over the body and a great mastery of the tools used in the daily struggle to reach a physiological balance. It is therefore a disease in which health education plays an important role, since patients are expected to reach a certain autonomy in the management of their disease. But how can the patients' autonomy be promoted? This is the question to which this study tried to answer from the perspective of socio-cultural psychology. The study was launched by the Cantonal Diabetes Program Vaud and aimed at evaluating a health education setting located in the east region of the Canton Vaud. It was based on both quantitative and qualitative methodological approaches. The results showed that there is a correlation between the number of hospitalizations and the quality of support provided by this particular health education setting. Moreover, the acquisition of expertise appears to be a distributed and collective process based upon the actors' active participation in various types of activities and involving and extended network. Further research is now required in order to examine how health education might be grasped through the lens of social-cultural psychology.

Constitutively active mutants of the alpha 1B-adrenergic receptor: role of highly conserved polar amino acids in receptor activation.

Site-directed mutagenesis and molecular dynamics simulations of the alpha 1B-adrenergic receptor (AR) were combined to explore the potential molecular changes correlated with the transition from R (inactive state) to R (active state). Using molecular dynamics analysis we compared the structural/dynamic features of constitutively active mutants with those of the wild type and of an inactive alpha 1B-AR to build a theoretical model which defines the essential features of R and R. The results of site-directed mutagenesis were in striking agreement with the predictions of the model supporting the following hypothesis. (i) The equilibrium between R and R depends on the equilibrium between the deprotonated and protonated forms, respectively, of D142 of the DRY motif. In fact, replacement of D142 with alanine confers high constitutive activity to the alpha 1B-AR. (ii) The shift of R143 of the DRY sequence out of a conserved 'polar pocket' formed by N63, D91, N344 and Y348 is a feature common to all the active structures, suggesting that the role of R143 is fundamental for mediating receptor activation. Disruption of these intramolecular interactions by replacing N63 with alanine constitutively activates the alpha 1B-AR. Our findings might provide interesting generalities about the activation process of G protein-coupled receptors.