Experimental Modeling of Flavonoid-Biomembrane Interactions

Nonspecific interactions of flavonoids with lipids can alter the membrane's features (e.g., thickness and fluctuations) as well as influence their therapeutic potentials. However, relatively little is known about the details of how flavonoids interact with lipid components. Structure-dependent interactions of a variety of flavonoids with phospholipid monolayers on a mercury (Hg) film electrode were established by rapid cyclic voltammetry (RCV). The data revealed that flavonoids adopting a planar configuration altered the membrane properties more significantly than nonplanar flavonoids. Quercetin, rutin, and tiliroside were selected for follow-up experiments with Langmuir monolayers, Brewster angle microscopy (BAM), and small-angle X-ray scattering (SAXS). Relaxation phenomena in DOPC monolayers and visualization of the surface with BAM revealed a pronounced monolayer stabilization effect with both quercetin and tiliroside, whereas rutin disrupted the monolayer structure rendering the surface entirely smooth. SAXS showed a monotonous membrane thinning for all compounds studied associated with an increase in the mean fluctuations of the membrane. Rutin, quercetin, and tiliroside decreased the bilayer thickness of DOPC by ∼0.45, 0.8, and 1.1 Å at 6 mol %, respectively. In addition to the novelty of using lipid monolayers to systematically characterize the structure-activity relationship (SAR) of a variety of flavonoids, this is the first report investigating the effect of tiliroside with biomimetic membrane models. All the flavonoids studied are believed to be localized in the lipid/water interface region. Both this localization and the membrane perturbations have implications for their therapeutic activity

F O R M U L A RY M A N A G E M E N T Comparison of Risedronate to Alendronate and Calcitonin for Early Reduction of Nonvertebral Fracture Risk: Results From a Managed Care Administrative Claims Database

steoporosis is an increasing concern for older adults as painful fragility fractures can significantly affect overall health and quality of life. In the United States, the lifetime risk of fracture at age 50 is estimated at 40% for women and 12.5% for men. Reductions in relative risk (RR) of radiographic vertebral fracture were comparable for the 2 drugs, ranging from 41% to 49% over 3 years (3.0% to 10.9% absolute risk reduction [ARR]). 9 Osteoporosis is considered to be a "silent" disease, and patients may fail to be compliant with therapy due to multiple ). Most were women (93%); mean age was similar for alendronate and risedronate, and nasal calcitonin patients were about 3 years older, on average. Risedronate and alendronate patients were more likely to have used estrogen, while nasal calcitonin patients were more likely to have been hospitalized and had higher use of concomitant medications and more physician visits. Relative risks were adjusted for these differences. Risedronate and alendronate patients were similar with respect to these indicators of general health status. In the 6-month analysis, nonvertebral fractures were observed in 2.2% of patients receiving nasal calcitonin, 1.4% of patients receiving alendronate, and 0.6% of patients receiving risedronate. The adjusted RR reduction was 69% for risedronate versus calcitonin (RR = 0.31; 95% CI, 0.12 to 0.81; P = 0.02), 54% for risedronate versus alendronate (RR = 0.46; 95% CI, 0.20 to 1.06; P = 0.07), and 26% for alendronate versus calcitonin (RR = 0.74; 95% CI, 0.43 to 1.27; P = 0.28). In the 12-month analysis, nonvertebral fracture rates were 2.9% for nasal calcitonin, 2.4% for alendronate, and 0.9% for risedronate patients. The adjusted RR reduction was 75% for risedronate versus calcitonin (RR = 0.25; 95% CI, 0.10 to 0.64; P<0.01), 59% for risedronate versus alendronate (RR = 0.41; 95% CI, 0.18 to 0.94; P = 0.04), and 25% for alendronate versus calcitonin (RR = 0.75; 95% CI, 0.45 to 1.25; P = 0.27). CONCLUSIONS: This analysis of medical and pharmacy claims contained in an administrative database confirms the early fracture reduction with risedronate that was shown in randomized clinical trials. Risedronate was more effective than calcitonin in reducing the risk of nonvertebral fractures within the first 6 months of treatment. Risedronate was more effective than either calcitonin or alendronate in reducing the risk of nonvertebral fractures within 12 months of treatment

Cellulolytic Bacteria in the foregut of the dromedary camel (Camelus dromedarius)

Foregut digesta from five feral dromedary camels were inoculated into three different enrichment media: cotton thread, filter paper, and neutral detergent fiber. A total of 283 16S rRNA gene sequences were assigned to 33 operational taxonomic units by using 99% species-level identity. LIBSHUFF revealed significant differences in the community composition across all three libraries

Electroweak Baryogenesis and Dark Matter with an approximate R-symmetry

It is well known that R-symmetric models dramatically alleviate the SUSY flavor and CP problems. We study particular modifications of existing R-symmetric models which share the solution to the above problems, and have interesting consequences for electroweak baryogenesis and the Dark Matter (DM) content of the universe. In particular, we find that it is naturally possible to have a strongly first-order electroweak phase transition while simultaneously relaxing the tension with EDM experiments. The R-symmetry (and its small breaking) implies that the gauginos (and the neutralino LSP) are pseudo-Dirac fermions, which is relevant for both baryogenesis and DM. The singlet superpartner of the U(1)_Y pseudo-Dirac gaugino plays a prominent role in making the electroweak phase transition strongly first-order. The pseudo-Dirac nature of the LSP allows it to behave similarly to a Dirac particle during freeze-out, but like a Majorana particle for annihilation today and in scattering against nuclei, thus being consistent with current constraints. Assuming a standard cosmology, it is possible to simultaneously have a strongly first-order phase transition conducive to baryogenesis and have the LSP provide the full DM relic abundance, in part of the allowed parameter space. However, other possibilities for DM also exist, which are discussed. It is expected that upcoming direct DM searches as well as neutrino signals from DM annihilation in the Sun will be sensitive to this class of models. Interesting collider and Gravity-wave signals are also briefly discussed.Comment: 50 pages, 10 figure

Liver Enzyme Abnormalities and Associated Risk Factors in HIV Patients on Efavirenz-Based HAART with or without Tuberculosis Co-Infection in Tanzania.

To investigate the timing, incidence, clinical presentation, pharmacokinetics and pharmacogenetic predictors for antiretroviral and anti-tuberculosis drug induced liver injury (DILI) in HIV patients with or without TB co-infection. A total of 473 treatment naïve HIV patients (253 HIV only and 220 with HIV-TB co-infection) were enrolled prospectively. Plasma efavirenz concentration and CYP2B6*6, CYP3A5*3, *6 and *7, ABCB1 3435C/T and SLCO1B1 genotypes were determined. Demographic, clinical and laboratory data were collected at baseline and up to 48 weeks of antiretroviral therapy. DILI case definition was according to Council for International Organizations of Medical Sciences (CIOMS). Incidence of DILI and identification of predictors was evaluated using Cox Proportional Hazards Model. The overall incidence of DILI was 7.8% (8.3 per 1000 person-week), being non-significantly higher among patients receiving concomitant anti-TB and HAART (10.0%, 10.7 per 1000 person-week) than those receiving HAART alone (5.9%, 6.3 per 1000 person-week). Frequency of CYP2B6*6 allele (p = 0.03) and CYP2B6*6/*6 genotype (p = 0.06) was significantly higher in patients with DILI than those without. Multivariate cox regression model indicated that CYP2B6*6/*6 genotype and anti-HCV IgG antibody positive as significant predictors of DILI. Median time to DILI was 2 weeks after HAART initiation and no DILI onset was observed after 12 weeks. No severe DILI was seen and the gain in CD4 was similar in patients with or without DILI. Antiretroviral and anti-tuberculosis DILI does occur in our setting, presenting early following HAART initiation. DILI seen is mild, transient and may not require treatment interruption. There is good tolerance to HAART and anti-TB with similar immunological outcomes. Genetic make-up mainly CYP2B6 genotype influences the development of efavirenz based HAART liver injury in Tanzanians