213 research outputs found
Rapidity gaps in perturbative QCD
We analyze diffractive deep inelastic scattering within perturbative QCD by
studying lepton scattering on a heavy quark target. Simple explicit expressions
are derived in impact parameter space for the photon wave function and the
scattering cross sections corresponding to single and double Coulomb gluon
exchange. At limited momentum transfers to the target, the results agree with
the general features of the ``aligned jet model''. The color--singlet exchange
cross section receives a leading twist contribution only from the aligned jet
region, where the transverse size of the photon wave function remains finite in
the Bjorken scaling limit. In contrast to inclusive DIS, in diffractive events
there is no leading twist contribution to from the lowest
order photon Fock state, and the cross section for heavy quarks is
power suppressed in the quark mass. There are also important contributions with
large momentum transfer to the target, which corresponds to events having high
transverse momentum production in both the projectile and target rapidity
regions, separated by a rapidity gap.Comment: 27 pages, LaTeX, 6 figures. Duplicate figure removed, paper unchange
Future therapeutic targets in rheumatoid arthritis?
Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by persistent joint inflammation. Without adequate treatment, patients with RA will develop joint deformity and progressive functional impairment. With the implementation of treat-to-target strategies and availability of biologic therapies, the outcomes for patients with RA have significantly improved. However, the unmet need in the treatment of RA remains high as some patients do not respond sufficiently to the currently available agents, remission is not always achieved and refractory disease is not uncommon. With better understanding of the pathophysiology of RA, new therapeutic approaches are emerging. Apart from more selective Janus kinase inhibition, there is a great interest in the granulocyte macrophage-colony stimulating factor pathway, Bruton's tyrosine kinase pathway, phosphoinositide-3-kinase pathway, neural stimulation and dendritic cell-based therapeutics. In this review, we will discuss the therapeutic potential of these novel approaches
HERMES: Towards an Integrated Toolbox to Characterize Functional and Effective Brain Connectivity
The analysis of the interdependence between time series has become an important field of research in the last years, mainly as a result of advances in the characterization of dynamical systems from the signals they produce, the introduction of concepts such as generalized and phase synchronization and the application of information theory to time series analysis. In neurophysiology, different analytical tools stemming from these concepts have added to the ‘traditional’ set of linear methods, which includes the cross-correlation and the coherency function in the time and frequency domain, respectively, or more elaborated tools such as Granger Causality. This increase in the number of approaches to tackle the existence of functional (FC) or effective connectivity (EC) between two (or among many) neural networks, along with the mathematical complexity of the corresponding time series analysis tools, makes it desirable to arrange them into a unified-easy-to-use software package. The goal is to allow neuroscientists, neurophysiologists and researchers from related fields to easily access and make use of these analysis methods from a single integrated toolbox. Here we present HERMES (http://hermes.ctb.upm.es), a toolbox for the Matlab® environment (The Mathworks, Inc), which is designed to study functional and effective brain connectivity from neurophysiological data such as multivariate EEG and/or MEG records. It includes also visualization tools and statistical methods to address the problem of multiple comparisons. We believe that this toolbox will be very helpful to all the researchers working in the emerging field of brain connectivity analysis
A new schedule of fotemustine in temozolomide-pretreated patients with relapsing glioblastoma
In the present study we investigated the feasibility and effectiveness of a new biweekly schedule of fotemustine (FTM) in patients with recurrent glioblastoma, after at least one previous treatment. The primary endpoint was progression-free survival at 6 months; secondary objectives were clinical response, overall survival, disease-free survival, and toxicity. Forty patients (median age 52.8 years; median Karnofsky Performance Status at progression 90) underwent second-line chemotherapy with FTM. Selected patients were previously treated with a standard radiotherapy course with concomitant temozolomide (TMZ). After tumor relapse or progression proven by magnetic resonance imaging (MRI), all patients underwent chemotherapy with FTM, given intravenously at dose of 80 mg/m2 every 2 weeks for five consecutive administrations (induction phase), and then every 3 weeks at 100 mg/m2 as maintenance. A total of 329 infusions were administered; the median number of cycles administered was 8. All patients completed the induction phase, and 29 patients received at least one maintenance infusion. Response to treatment was assessed using MacDonald criteria. One complete response [2.5%, 95% confidence interval (CI): 0–10%], 9 partial responses (22.5%, 95% CI: 15–37%), and 16 stable diseases (40%, 95% CI: 32–51%) were observed. Median time to progression was 6.7 months (95% CI: 3.9–9.1 months). Progression-free survival at 6 months was 61%. Median survival from beginning of FTM chemotherapy was 11.1 months. The schedule was generally well tolerated; the main toxicities were hematologic (grade 3 thrombocytopenia in two cases). To the best of our knowledge, this is the first report specifically dealing with the use of a biweekly induction schedule of FTM. The study demonstrates that FTM has therapeutic efficacy as single-drug second-line chemotherapy with a favorable safety profile
Using brain cell-type-specific protein interactomes to interpret neurodevelopmental genetic signals in schizophrenia
Genetics have nominated many schizophrenia risk genes and identified convergent signals between schizophrenia and neurodevelopmental disorders. However, functional interpretation of the nominated genes in the relevant brain cell types is often lacking. We executed interaction proteomics for six schizophrenia risk genes that have also been implicated in neurodevelopment in human induced cortical neurons. The resulting protein network is enriched for common variant risk of schizophrenia in Europeans and East Asians, is down-regulated in layer 5/6 cortical neurons of individuals affected by schizophrenia, and can complement fine-mapping and eQTL data to prioritize additional genes in GWAS loci. A sub-network centered on HCN1 is enriched for common variant risk and contains proteins (HCN4 and AKAP11) enriched for rare protein-truncating mutations in individuals with schizophrenia and bipolar disorder. Our findings showcase brain cell-type-specific interactomes as an organizing framework to facilitate interpretation of genetic and transcriptomic data in schizophrenia and its related disorders
Recurrent Ischemic Stroke and Bleeding in Patients With Atrial Fibrillation Who Suffered an Acute Stroke While on Treatment With Nonvitamin K Antagonist Oral Anticoagulants: The RENO-EXTEND Study
Background:
In patients with atrial fibrillation who suffered an ischemic stroke while on treatment with nonvitamin K antagonist oral anticoagulants, rates and determinants of recurrent ischemic events and major bleedings remain uncertain.
Methods:
This prospective multicenter observational study aimed to estimate the rates of ischemic and bleeding events and their determinants in the follow-up of consecutive patients with atrial fibrillation who suffered an acute cerebrovascular ischemic event while on nonvitamin K antagonist oral anticoagulant treatment. Afterwards, we compared the estimated risks of ischemic and bleeding events between the patients in whom anticoagulant therapy was changed to those who continued the original treatment.
Results:
After a mean follow-up time of 15.0±10.9 months, 192 out of 1240 patients (15.5%) had 207 ischemic or bleeding events corresponding to an annual rate of 13.4%. Among the events, 111 were ischemic strokes, 15 systemic embolisms, 24 intracranial bleedings, and 57 major extracranial bleedings. Predictive factors of recurrent ischemic events (strokes and systemic embolisms) included CHA2DS2-VASc score after the index event (odds ratio [OR], 1.2 [95% CI, 1.0–1.3] for each point increase; P=0.05) and hypertension (OR, 2.3 [95% CI, 1.0–5.1]; P=0.04). Predictive factors of bleeding events (intracranial and major extracranial bleedings) included age (OR, 1.1 [95% CI, 1.0–1.2] for each year increase; P=0.002), history of major bleeding (OR, 6.9 [95% CI, 3.4–14.2]; P=0.0001) and the concomitant administration of an antiplatelet agent (OR, 2.8 [95% CI, 1.4–5.5]; P=0.003). Rates of ischemic and bleeding events were no different in patients who changed or not changed the original nonvitamin K antagonist oral anticoagulants treatment (OR, 1.2 [95% CI, 0.8–1.7]).
Conclusions:
Patients suffering a stroke despite being on nonvitamin K antagonist oral anticoagulant therapy are at high risk of recurrent ischemic stroke and bleeding. In these patients, further research is needed to improve secondary prevention by investigating the mechanisms of recurrent ischemic stroke and bleeding
High Energy Photoproduction
The study of photoproduction reactions has gained a unique opportunity with
the HERA data. The high center of mass energy allows to carry out quantitative
tests of QCD, to explore the substructure of both the photon and the proton and
to shed new light on soft and diffractive processes. In this report we review
the HERA results, comparing them with the reach of fixed target photoproduction
experiments and complementary measurements from and hadron colliders.Comment: 100 pages including 53 figures. To be published in the "Rivista del
Nuovo Cimento
Atazanavir and darunavir in pregnant women with HIV: Evaluation of laboratory and clinical outcomes from an observational national study
Background: Atazanavir and darunavir represent the main HIV PIs recommended in pregnancy, but comparativedata in pregnant women are limited.We assessed the safety and activity profile of these two drugs in pregnancyusing data from a national observational study.Methods: Women with atazanavir or darunavir exposure in pregnancy were evaluated for laboratory measuresand main pregnancy outcomes (e.g. preterm delivery, low birthweight, non-elective caesarean section and neonatalgestational age-adjusted birthweight Z-score).Results: Final analysis included 500 pregnancies with either atazanavir (n"409) or darunavir (n"91) exposure.No differences in pregnancy outcomes, weight gain in pregnancy, drug discontinuations, undetectable HIV-RNA,haemoglobin, ALT, total cholesterol, HDL cholesterol and LDL cholesterol were observed between the twogroups. At third trimester, exposure to darunavir was associated with higher levels of plasma triglycerides(median 235.5 versus 179 mg/dL; P"0.032) and a higher total cholesterol/HDL cholesterol ratio (median 4.03versus 3.27; P"0.028) and exposure to atazanavir was associated with higher levels of plasma bilirubin (1.54versus 0.32 mg/dL; P<0.001).Conclusions: In this observational study, the two main HIV PIs currently recommended by perinatal guidelinesshowed similar safety and activity in pregnancy, with no evidence of differences between the two drugs in termsof main pregnancy outcomes. Based on the minor differences observed in laboratory measures, prescribingphysicians might prefer either drug in some particular situations where the different impacts of treatment onlipid profile and bilirubin may have clinical relevance
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