On Limiting Case of the Stein-Weiss Type Inequality for the B-Riesz Potentials

Mathematics Subject Classification: Primary 42B20, 42B25, 42B35

B-Spline potential function for maximum a-posteriori image reconstruction in fluorescence microscopy

An iterative image reconstruction technique employing B-Spline potential function in a Bayesian framework is proposed for fluorescence microscopy images. B-splines are piecewise polynomials with smooth transition, compact support and are the shortest polynomial splines. Incorporation of the B-spline potential function in the maximum-a-posteriori reconstruction technique resulted in improved contrast, enhanced resolution and substantial background reduction. The proposed technique is validated on simulated data as well as on the images acquired from fluorescence microscopes (widefield, confocal laser scanning fluorescence and super-resolution 4Pi microscopy). A comparative study of the proposed technique with the state-of-art maximum likelihood (ML) and maximum-a-posteriori (MAP) with quadratic potential function shows its superiority over the others. B-Spline MAP technique can find applications in several imaging modalities of fluorescence microscopy like selective plane illumination microscopy, localization microscopy and STED. (C) 2015 Author(s).

Riesz potential versus fractional Laplacian

This paper starts by introducing the Grünwald–Letnikov derivative, the Riesz potential and the problem of generalizing the Laplacian. Based on these ideas, the generalizations of the Laplacian for 1D and 2D cases are studied. It is presented as a fractional version of the Cauchy–Riemann conditions and, finally, it is discussed with the n-dimensional Laplacian.

Riesz potential versus fractional Laplacian

This paper starts by introducing the Grünwald–Letnikov derivative, the Riesz potential and the problem of generalizing the Laplacian. Based on these ideas, the generalizations of the Laplacian for 1D and 2D cases are studied. It is presented as a fractional version of the Cauchy–Riemann conditions and, finally, it is discussed with the n-dimensional Laplacian.

Le(a-b-) phenotype: potential risk factor for infection by the RH strain of Toxoplasma gondii in pregnancy

The Lewis histo-blood group system is characterized by the expression of the Lea and Le(b) antigens in the gastrointestinal tract, whose synthesis results in interactions between alpha 2-L-fucosyltransferase (FUTII) and alpha 3/4-L-fucosyltransferase (FUTIII) enzymes coded by the FUT2 (19q. 13.3) and FUT3 (19p13.3) genes. FUTII and FUTIII fucosylate the type 1 oligosaccharide precursor (Gal beta 1 -> 3NAcGlc beta 1 -> 3-R) at distinct positions to form H type 1 (Fuc alpha 1. 2Gal beta 1. 3NAcGlc beta 1 -> 3-R) and Le(a) (Gal beta 1 -> 3[Fuc alpha 1 -> 4] NAcGlc beta 1 -> 3-R) antigens, respectively. The fucosylation of H type 1 antigens by FUTIII results in the Leb antigen (Fuc alpha 1. 2Gal beta 1. 3[Fuca1. 4] NAcGlc beta 1. 3-R). Thus, the presence of the FUTII and FUTIII enzymes leads to the expression of the Le(a+b+) phenotype, while the presence of only FUTIII allows the expression of the Le(a+b-) phenotype. The absence of the FUTIII enzyme leads to the expression of the Le(a-b-) phenotype, independent of the presence or absence of FUTII. Point mutations in FUT2 and FUT3 genes change the activity of these enzymes, impair the synthesis of Le(a) and Le(b) antigens, and contribute to the variability of Lewis phenotypes in the gastrointestinal tract. Toxoplasma gondii, an apicomplexan parasite that infects a large proportion of the world's population, utilizes the gastrointestinal tract as an infection route and seems to adhere to glycosylated molecules to invade human cells. These apparently independent events may be related. The aim of this study was to test the hypothesis that there is an association between the Lewis histo-blood group system and infection by T. gondii. Two hundred and nine serum samples collected from pregnant women were submitted to screening tests to detect anti-T. gondii antibodies, employing the indirect hemagglutination method. ELISA was utilized to identify IgG class anti-T. gondii antibodies specific for the RH strain. A hundred and ninety-five samples with concordant results for both methods were selected to form two groups: seropositive (G1) and seronegative (G2). The G428A mutation of the FUT2 gene, and T202C and C314T of the FUT3 gene, which allow inference of the gastrointestinal tract Lewis phenotypes, were identified using PCR-RFLP and PCR-SSP methods, respectively. Among the 195 samples selected, 116 (59.5%) were seropositive and 79 (40.5%) were seronegative. In G1, 68 (58.6%) were classified as Le(a+b+), 30 (25.9%) as Le(a+b-), and 18 (15.5%) as Le(a-b-), and in G2, 67 (84.8%) were classified as Le(a+b+), 12 (15.2%) as Le(a+b-), and 0 (0%) as Le(a-b-) (P < 0.0001). The Le(a-b-) phenotype is associated with a high risk of RH strain T. gondii infection when compared with the Le(a+b+) [P = 0.0001; OR = 36,460; 95%CI = 2.152-617,680] and Le(a+b-) phenotypes [P = 0.0118; OR = 15,165; 95%CI = 0.8463-271,710]. The Le(a+b-) phenotype showed a higher risk compared to the Le(a+b+) phenotype [P = 0.0206; OR = 2463; 95%CI = 2463-5214]. The results suggest that the Le(a-b-) phenotype is strongly associated with a greater risk of infection by the RH strain of T. gondii compared to the other phenotypes. It is possible that the absence of fucosylation of the type 1 oligosaccharide precursor as well as the variations in the structures of the Le(a) and Le(b) antigens influence susceptibility to infection by this parasite.

Dually Active HIV/HBV Antiretrovirals Protect Against Incident Hepatitis B Infections: Potential for Prophylaxis.

BACKGROUND  Hepatitis-B virus (HBV) has a detrimental effect on HIV natural course, and HBV vaccination is less effective in the HIV infected. We examine the protective effect of dually active antiretroviral therapy (DAART) for HIV/HBV (Tenofovir/Lamivudine/Emtricitabine) in a large cohort encompassing heterosexuals, men-who-have-sex-with-men (MSM), and intravenous drug users (IDU), who are HIV-infected yet susceptible to HBV, with comprehensive follow-up data about risky behavior and immunological profile. METHODS  We defined an incident HBV infection as the presence of any of HBV serological markers (HBsAg/AntiHBc/HBV-DNA) following a negative baseline AntiHBc test. Patients with positive AntiHBs were excluded. Cox proportional hazard models were utilized, with an incident case of HBV infection as the outcome variable. RESULTS  We analyzed 1,716 eligible patients from the Swiss HIV Cohort Study with 177 incident HBV cases. DAART was negatively associated with incident HBV infection (hazard ratio 0.4, 95%CI 0.2-0.6). This protective association was robust to adjustment (0.3, 0.2-0.5) for condomless sex, √CD4 count, drug use, and patients' demographics. Condomless sex (1.9,1.4-2.6), belonging to MSM (2.7,1.7-4.2) or IDU (3.8,2.4-6.1) were all associated with higher HBV hazard. CONCLUSIONS  Our study suggests that DAART, independently of CD4 count and risky behavior, has a potentially strong public health impact including pre-exposure prophylaxis of HBV co-infection.

The Stein-Weiss Type Inequality for Fractional Integrals, Associated with the Laplace-Bessel Differential Operator

2000 Math. Subject Classification: Primary 42B20, 42B25, 42B35

An alternative B cell development program

Two major types of B cells, the antibody-producing cells of the immune system, are classically distinguished in the spleen: marginal zone (MZ) and follicular (FO). In addition, FO B cells are subdivided into FO I and FO II cells, based on the amount of surface IgM. MZ B cells, which surround the splenic follicles, rapidly produce IgM in response to blood-borne pathogens without T cell help, while T cell-dependent production of high affinity, isotype-switched antibodies is ascribed to FO I cells. The significance of FO II cells and the mechanism underlying B cell fate choices are unclear. We showed that FO II cells express more Sca1 than FO I cells and originate from a distinct B cell development program, marked by high expression of Sca1. MZ B cells can derive from the “canonical” Sca1lo pathways, as well as from the Sca1hi program, although the Sca1hi program shows a stronger MZ bias than the Sca1lo program, and extensive phenotypic plasticity exists between MZ and FO II, but not between MZ and FO I cells. The Sca1hi program is induced by hematopoietic stress and generates B cells with an Igλ-enriched repertoire. In aged mice, the canonical B cell development pathway is impaired, while the Sca1hi program is increased. Furthermore, we showed that a population of unknown function, defined as Lin-c-kit+Sca1+ (LSK-), contains early lymphoid precursors, with primarily B cell potential in vivo. Our data suggest that LSK- cells may represent a distinct precursor for the Sca1hi program in the bone marrow.

Genetic diversity of EBV-encoded LMP1 in the Swiss HIV Cohort Study and implication for NF-Κb activation

Epstein-Barr virus (EBV) is associated with several types of cancers including Hodgkin's lymphoma (HL) and nasopharyngeal carcinoma (NPC). EBV-encoded latent membrane protein 1 (LMP1), a multifunctional oncoprotein, is a powerful activator of the transcription factor NF-κB, a property that is essential for EBV-transformed lymphoblastoid cell survival. Previous studies reported LMP1 sequence variations and induction of higher NF-κB activation levels compared to the prototype B95-8 LMP1 by some variants. Here we used biopsies of EBV-associated cancers and blood of individuals included in the Swiss HIV Cohort Study (SHCS) to analyze LMP1 genetic diversity and impact of sequence variations on LMP1-mediated NF-κB activation potential. We found that a number of variants mediate higher NF-κB activation levels when compared to B95-8 LMP1 and mapped three single polymorphisms responsible for this phenotype: F106Y, I124V and F144I. F106Y was present in all LMP1 isolated in this study and its effect was variant dependent, suggesting that it was modulated by other polymorphisms. The two polymorphisms I124V and F144I were present in distinct phylogenetic groups and were linked with other specific polymorphisms nearby, I152L and D150A/L151I, respectively. The two sets of polymorphisms, I124V/I152L and F144I/D150A/L151I, which were markers of increased NF-κB activation in vitro, were not associated with EBV-associated HL in the SHCS. Taken together these results highlighted the importance of single polymorphisms for the modulation of LMP1 signaling activity and demonstrated that several groups of LMP1 variants, through distinct mutational paths, mediated enhanced NF-κB activation levels compared to B95-8 LMP1.

Potential of chemically modified hydrophilic surface characteristics to support tissue integration of titanium dental implants

In the past, several modifications of specific surface properties such as topography, structure, chemistry, surface charge, and wettability have been investigated to predictably improve the osseointegration of titanium implants. The aim of the present review was to evaluate, based on the currently available evidence, the impact of hydrophilic surface modifications of titanium for dental implants. A surface treatment was performed to produce hydroxylated/hydrated titanium surfaces with identical microstructure to either acid-etched, or sand-blasted, large grit and acid-etched substrates, but with hydrophilic character. Preliminary in vitro studies have indicated that the specific properties noted for hydrophilic titanium surfaces have a significant influence on cell differentiation and growth factor production. Animal experiments have pointed out that hydrophilic surfaces improve early stages of soft tissue and hard tissue integration of either nonsubmerged or submerged titanium implants. This data was also corroborated by the results from preliminary clinical studies. In conclusion, the present review has pointed to a potential of hydrophilic surface modifications to support tissue integration of titanium dental implants.