Membrane effects of aminoglycoside antibiotics measured in liposomes containing the fluorescent probe, 1-anilino-8-naphthalene sulfonate

The mechanism of membrane disturbance by aminoglycoside antibiotics was investigated in liposomes containing the fluorescent probe, 1-anilino-8-naphthalene sulfonate (ANS). Liposomes of PC and different anionic phospholipids (1:1 to 15:1 molar ratios) were challenged with aminoglycosides in the presence of low (1 microM) and high (3 mM) concentrations of calcium. Liposomes containing PIP2 showed the greatest drug-induced changes in ANS fluorescence in the presence of high and low concentrations of calcium and at all PC:PIP2 molar ratios tested. Liposomes containing other anionic phospholipids (PS, PI and PIP) were not reactive toward aminoglycosides in the presence of 3 mM calcium or when the ratio of PC to anionic lipid was increased to 10:1. The aminoglycoside-induced changes of ANS fluorescence were not due to any changes in the emission spectrum of ANS, nor to changes in quantum yield, nor to a change in the binding affinity of ANS. It is concluded that a specific aminoglycoside-PIP2 interaction results in phase separation of PC and PIP2 and thus increases the number of available ANS binding sites in PC:PIP2 liposomes.     

Sound Stimulates Labeling of Polyphosphoinositides in the Auditory Organ of the Noctuid Moth

Abstract: The Noctuid moth possesses a simple auditory structure suitable for the investigation of biochemical correlates of sound stimulation in vivo. Stimulation with pulsed tones increased ³²P incorporation into polyphos-phoinositides but not into ATP or other lipids. The effect was seen in the scoloparium (sensory structure) but hot in the nodular sclerite, an adjacent nonsensory tissue. It was also not seen when the stimulus was a continuous tone, leading to adaptation of the action potential.     

Combined therapies in osteoporosis: bisphosphonates and vitamin D-hormone analogs

During the last two decades, the development of new, highly effective therapeutics (e.g. bisphosphonates, SERMs, strontium ranelate and PTH) has significantly extended the spectrum of osteoporosis therapy. However, the interest of combining bone-active agents and/or Vitamin D and calcium is still being debated, and is restricted to a very marginal set of compounds (Alendronate and native Vitamin D). On the other hand, Vitamin D-hormone analogs, calcitriol, and alfacalcidol, have repeatedly demonstrated their effectiveness in being valuable alternatives compared to native Vitamin D in this setting. A growing amount of data documents the pre-clinical and clinical efficacies of combinations of bisphosphonates with calcitriol, or with alfacalcidol in primary and secondary osteoporosis. This exhaustive review of the available animal and clinical data aimed at comparing the theoretical with demonstrated absolute and relative benefits of those therapeutic approaches. Most of the pre-clinical and clinical data in PMOP suggest significant, clinical improvements in response to combination therapies versus monotherapies in postmenopausal osteoporosis. As a investigated by most of the currently available trials, a daily dose of alendronate 10 mg or a weekly dose of Alendronate 70 m plus alfacalcidol 0.5-1.0 microg daily plus alfacalcidol 0.5 microg seems to surpass other combinations when BMD and bone metabolism markers are considered. A synergy with bisphosphonates in reducing the fracture episodes may lie in the pleiotropic effects of D-hormone analogs on musculoskeletal, immunological and neurological systems. Negative interactions between both drugs have not yet been reported, while a reduction of hypercalcuria episodes has been noted in combination therapies, as compared to monotherapies involving high doses of Vitamin D, calcitriol, or alfacalcidol. Based on the possible reduction of periodic safety checks of calcemia, an improved compliance could then be expected, which would, in turn, generate a better end result. However, to document this, long-term, high quality comparative studies with factorial designs are needed to determine which role this alternative should play in the management of postmenopausal, male, and glucocorticoid-induced osteoporosis.     

Methods for peptide identification by spectral comparison

Background  

Tandem mass spectrometry followed by database search is currently the predominant technology for peptide sequencing in shotgun proteomics experiments. Most methods compare experimentally observed spectra to the theoretical spectra predicted from the sequences in protein databases. There is a growing interest, however, in comparing unknown experimental spectra to a library of previously identified spectra. This approach has the advantage of taking into account instrument-dependent factors and peptide-specific differences in fragmentation probabilities. It is also computationally more efficient for high-throughput proteomics studies.     

Porous gelatin hydrogels: 1. Cryogenic formation and structure analysis

In the present work, porous gelatin scaffolds were prepared by cryogenic treatment of a chemically cross-linked gelatin hydrogel, followed by removal of the ice crystals formed through lyophilization. This technique often leads to porous gels with a less porous skin. A simple method has been developed to solve this problem. The present study demonstrates that the hydrogel pore size decreased with an increasing gelatin concentration and with an increasing cooling rate of the gelatin hydrogel. Variation of the cryogenic parameters applied also enabled us to develop scaffolds with different pore morphologies (spherical versus transversal channel-like pores). In our opinion, this is the first paper in which temperature gradients during controlled cryogenic treatment were applied to induce a pore size gradient in gelatin hydrogels. With a newly designed cryo-unit, temperature gradients of 10 and 30 degrees C were implemented during the freezing step, resulting in scaffolds with average pore diameters of, respectively, +/-116 and +/-330 microm. In both cases, the porosity and pore size decreased gradually through the scaffolds. Pore size and structure analysis of the matrices was accomplished through a combination of microcomputed tomography using different software packages (microCTanalySIS and Octopus), scanning electron microscopy analysis, and helium pycnometry.     

Photo-cross-linking between polymers derivatized with photoreactive ruthenium-1,4,5,8-tetraazaphenanthrene complexes and guanine-containing oligonucleotides

We have shown previously that complexes containing 1,4,5,8-tetraazaphenanthrene (TAP) ligands are able to form photoadducts with the guanine bases of DNA and oligonucleotides. In this work, we have exploited this specific photoreaction for carrying out photo-cross-linkings between guanine-containing oligonucleotides (G-ODNs) and biodegradable polymers derivatized with the photoreactive Ru(II) compounds. The aim in the future is to use these polymer conjugates as vectorizing agents of the metallic compounds inside the cells. Thus, photooxidizing Ru(II) complexes such as [Ru(TAP)3]2+ and [Ru(TAP)2phen]2+ (phen = 1,10-phenanthroline) have been derivatized by an oxyamine function to attach them, via an oxime ether linkage, to a soluble 6 or 80 kDa poly-[N-(2-hydroxyethyl)-l-glutamine] polymer that contains pendent aldehyde groups. It is demonstrated that the resulting Ru-labeled polymers exhibit photophysical properties and a photochemistry that are comparable with those of the free, nonattached complexes. The photo-cross-linkings with the G-ODNs are clearly detected by gel electrophoresis with the 6 kDa Ru conjugates upon illumination.     

Disruption of reducing pathways is not essential for efficient disulfide bond formation in the cytoplasm of <Emphasis Type="Italic">E. coli</Emphasis>

Background  

The formation of native disulfide bonds is a complex and essential post-translational modification for many proteins. The large scale production of these proteins can be difficult and depends on targeting the protein to a compartment in which disulfide bond formation naturally occurs, usually the endoplasmic reticulum of eukaryotes or the periplasm of prokaryotes. It is currently thought to be impossible to produce large amounts of disulfide bond containing protein in the cytoplasm of wild-type bacteria such as E. coli due to the presence of multiple pathways for their reduction.     

Minor differences in ADHD-related difficulties between boys and girls treated with atomoxetine for attention-deficit/hyperactivity disorder

Atomoxetine may improve ADHD-related difficulties and hence the quality of life (QoL) in children and adolescents. Perception of these difficulties may differ with the rater perspective (patient, parent, physician) or patients' sex. The objective of this study was to investigate QoL as reflected by perceived ADHD-related difficulties perceived from these three perspectives and compare boys and girls. Patients aged 6-17 with ADHD were treated with atomoxetine (target dose 0.5-1.2 mg/kg/day) in two studies. In both studies, ADHD-related difficulties were assessed after 8 and 24 weeks using the Global Impression of Perceived Difficulties (GIPD) instrument, which can be taken to reflect the patient's QoL from the three perspectives. Data from the two studies were combined and analyzed together in order to compare boys and girls. Four hundred and twenty-one patients were treated with atomoxetine, 338 boys and 83 girls. Three hundred and fifty-five patients completed the 8-week study period. QoL, as reflected by perceived ADHD-related difficulties (measured with GIPD), improved over time. Mean GIPD total scores showed a similar course over time for all rater groups, although the patients rated the degree of difficulties significantly lower than parents and physicians. The sexes did not differ significantly in mean GIPD total scores. The GIPD scores over time suggest that patients' QoL, as reflected by perceived ADHD-related difficulties, improved with time on atomoxetine. However, improvement did not differ significantly between boys and girls. Trial Registration: ClinicalTrials.gov Identifiers NCT00191516 and NCT00191737.     

The 3120 +1G-->A splicing mutation in CFTR is common in Brazilian cystic fibrosis patients.

Cystic fibrosis patients from Rio de Janeiro, Brazil, were screened for mutations in exons 11 and 16 of the cystic fibrosis transmembrane conductance regulator gene (CFTR) by a nonradioactive single-stranded conformational polymorphism (SSCP) analysis technique. This procedure was used to evaluate the undefined mutations in one or both alleles of 64 cystic fibrosis patients. Unusual SSCP profiles were investigated further by sequence analysis. Two patients were shown to carry the G542X mutation (exon 11) and five had the splicing mutation 3120+1G-->A(intron 16), one of them being homozygous for the mutation. This is the first report of the 3120+ IG-->A mutation in Brazil. where it appears to be a frequent disease-associated molecular alteration in the CFTR gene.     

Exposure,hazard, and vulnerability all contribute to Schistosoma haematobium re-infection in northern Senegal

BackgroundInfectious disease risk is driven by three interrelated components: exposure, hazard, and vulnerability. For schistosomiasis, exposure occurs through contact with water, which is often tied to daily activities. Water contact, however, does not imply risk unless the environmental hazard of snails and parasites is also present in the water. By increasing reliance on hazardous activities and environments, socio-economic vulnerability can hinder reductions in exposure to a hazard. We aimed to quantify the contributions of exposure, hazard, and vulnerability to the presence and intensity of Schistosoma haematobium re-infection.Methodology/Principal findingsIn 13 villages along the Senegal River, we collected parasitological data from 821 school-aged children, survey data from 411 households where those children resided, and ecological data from all 24 village water access sites. We fit mixed-effects logistic and negative binomial regressions with indices of exposure, hazard, and vulnerability as explanatory variables of Schistosoma haematobium presence and intensity, respectively, controlling for demographic variables. Using multi-model inference to calculate the relative importance of each component of risk, we found that hazard (Ʃw_{i =} 0.95) was the most important component of S. haematobium presence, followed by vulnerability (Ʃw_i = 0.91). Exposure (Ʃw_i = 1.00) was the most important component of S. haematobium intensity, followed by hazard (Ʃw_i = 0.77). Model averaging quantified associations between each infection outcome and indices of exposure, hazard, and vulnerability, revealing a positive association between hazard and infection presence (OR = 1.49, 95% CI 1.12, 1.97), and a positive association between exposure and infection intensity (RR 2.59–3.86, depending on the category; all 95% CIs above 1)Conclusions/SignificanceOur findings underscore the linkages between social (exposure and vulnerability) and environmental (hazard) processes in the acquisition and accumulation of S. haematobium infection. This approach highlights the importance of implementing both social and environmental interventions to complement mass drug administration.