Rapid tablet swelling and disintegration during exposure to brightness-mode ultrasound

Controlled tablet disintegration is useful for chemical consistency checks. This study monitored the swelling of 54 analgesia tablets from two different batches, during 13-6-MHz brightness-mode sonication and simultaneous video recording. The tablets were placed on an acoustic reflector inside a container and sonicated from the top. Sonication shortened the displacement half-life by 17%-27%. During tablet swelling, their speed of sound increased linearly, confirming the linearity of this process. Diagnostic ultrasound significantly decreased tablet disintegration times, supporting the ultrasound-microbubble interaction hypothesis.acceptedVersionPeer reviewe

Auto-validation of fluorescent primer extension genotyping assay using signal clustering and neural networks

BACKGROUND: SNP genotyping typically incorporates a review step to ensure that the genotype calls for a particular SNP are correct. For high-throughput genotyping, such as that provided by the GenomeLab SNPstream(® )instrument from Beckman Coulter, Inc., the manual review used for low-volume genotyping becomes a major bottleneck. The work reported here describes the application of a neural network to automate the review of results. RESULTS: We describe an approach to reviewing the quality of primer extension 2-color fluorescent reactions by clustering optical signals obtained from multiple samples and a single reaction set-up. The method evaluates the quality of the signal clusters from the genotyping results. We developed 64 scores to measure the geometry and position of the signal clusters. The expected signal distribution was represented by a distribution of a 64-component parametric vector obtained by training the two-layer neural network onto a set of 10,968 manually reviewed 2D plots containing the signal clusters. CONCLUSION: The neural network approach described in this paper may be used with results from the GenomeLab SNPstream instrument for high-throughput SNP genotyping. The overall correlation with manual revision was 0.844. The approach can be applied to a quality review of results from other high-throughput fluorescent-based biochemical assays in a high-throughput mode

Cathelicidins display conserved direct antiviral activity towards rhinovirus.

Human rhinoviruses (HRVs) are the most common cause of viral respiratory tract infections, and are associated with significant morbidity and mortality in immunocompromised individuals and patients with pre-existing pulmonary conditions. The therapeutic options available are extremely limited and therefore novel therapeutics for HRV infections are of significant interest. Cathelicidins have been shown to have potent antiviral activity against a range of pathogens and are known to be key immunomodulatory mediators during infection. We therefore assessed the antiviral potential of cathelicidins from humans and other mammalian species against HRV, together with the potential for the human cathelicidin to modulate apoptotic pathways and alter cell viability during HRV infection. We demonstrate that LL-37, the porcine cathelicidin Protegrin-1, and the ovine cathelicidin SMAP-29 display potent antiviral activity towards HRV and that this activity is visible when either the virus is exposed to the peptides prior to cell infection or after cells have been infected. We further demonstrate that, in contrast to established findings with bacterial infection models, LL-37 does not induce apoptosis or necrosis in HRV-infected lung epithelial cells at physiological or superphysiological concentrations, but does reduce the metabolic activity of infected cells compared to uninfected cells treated with similar peptide concentrations. Collectively, the findings from this study demonstrate that the mechanism of action of cathelicidins against rhinovirus is by directly affecting the virus and we propose that the delivery of exogenous cathelicidins, or novel synthetic analogues, represent an exciting and novel therapeutic strategy for rhinovirus infection

Particle Dark Matter Constraints from the Draco Dwarf Galaxy

It is widely thought that neutralinos, the lightest supersymmetric particles, could comprise most of the dark matter. If so, then dark halos will emit radio and gamma ray signals initiated by neutralino annihilation. A particularly promising place to look for these indicators is at the center of the local group dwarf spheroidal galaxy Draco, and recent measurements of the motion of its stars have revealed it to be an even better target for dark matter detection than previously thought. We compute limits on WIMP properties for various models of Draco's dark matter halo. We find that if the halo is nearly isothermal, as the new measurements indicate, then current gamma ray flux limits prohibit much of the neutralino parameter space. If Draco has a moderate magnetic field, then current radio limits can rule out more of it. These results are appreciably stronger than other current constraints, and so acquiring more detailed data on Draco's density profile becomes one of the most promising avenues for identifying dark matter.Comment: 13 pages, 6 figure

Citrullination Alters the Antiviral and Immunomodulatory Activities of the Human Cathelicidin LL-37 During Rhinovirus Infection

Human rhinoviruses (HRV) are the most common cause of viral respiratory tract infections. While normally mild and self-limiting in healthy adults, HRV infections are associated with bronchiolitis in infants, pneumonia in immunocompromised patients, and exacerbations of asthma and COPD. The human cathelicidin LL-37 is a host defense peptide (HDP) with broad immunomodulatory and antimicrobial activities that has direct antiviral effects against HRV. However, LL-37 is known to be susceptible to the enzymatic activity of peptidyl arginine deiminases (PAD), and exposure of the peptide to these enzymes results in the conversion of positively charged arginines to neutral citrullines (citrullination). Here, we demonstrate that citrullination of LL-37 reduced its direct antiviral activity against HRV. Furthermore, while the anti-rhinovirus activity of LL-37 results in dampened epithelial cell inflammatory responses, citrullination of the peptide, and a loss in antiviral activity, ameliorates this effect. This study also demonstrates that HRV infection upregulates PAD2 protein expression, and increases levels of protein citrullination, including histone H3, in human bronchial epithelial cells. Increased PADI gene expression and HDP citrullination during infection may represent a novel viral evasion mechanism, likely applicable to a wide range of pathogens, and should therefore be considered in the design of therapeutic peptide derivatives

Helix compactness and stability: Electron structure calculations of conformer dependent thermodynamic functions

Structure, stability, cooperativity and molecular packing of two major backbone forms: 310-helix and β-strand are investigated. Long models HCO-(Xxx)n-NH2 Xxx = Gly and (l-)Ala, n ⩽ 34, are studied at two levels of theory including the effect of dispersion forces. Structure and folding preferences are established, the length modulated cooperativity and side-chain determined fold compactness is quantified. By monitoring ΔG°β→α rather than the electronic energy, ΔEβ→α, it appears that Ala is a much better helix forming residue than Gly. The achiral Gly forms a more compact 310-helix than any chiral amino acid residue probed here for l-Ala

Adults with RRM2B-related mitochondrial disease have distinct clinical and molecular characteristics.

Mutations in the nuclear-encoded mitochondrial maintenance gene RRM2B are an important cause of familial mitochondrial disease in both adults and children and represent the third most common cause of multiple mitochondrial DNA deletions in adults, following POLG [polymerase (DNA directed), gamma] and PEO1 (now called C10ORF2, encoding the Twinkle helicase) mutations. However, the clinico-pathological and molecular features of adults with RRM2B-related disease have not been clearly defined. In this multicentre study of 26 adult patients from 22 independent families, including five additional cases published in the literature, we show that extra-ocular neurological complications are common in adults with genetically confirmed RRM2B mutations. We also demonstrate a clear correlation between the clinical phenotype and the underlying genetic defect. Myopathy was a prominent manifestation, followed by bulbar dysfunction and fatigue. Sensorineural hearing loss and gastrointestinal disturbance were also important findings. Severe multisystem neurological disease was associated with recessively inherited compound heterozygous mutations with a mean age of disease onset at 7 years. Dominantly inherited heterozygous mutations were associated with a milder predominantly myopathic phenotype with a later mean age of disease onset at 46 years. Skeletal muscle biopsies revealed subsarcolemmal accumulation of mitochondria and/or cytochrome c oxidase-deficient fibres. Multiple mitochondrial DNA deletions were universally present in patients who underwent a muscle biopsy. We identified 18 different heterozygous RRM2B mutations within our cohort of patients, including five novel mutations that have not previously been reported. Despite marked clinical overlap between the mitochondrial maintenance genes, key clinical features such as bulbar dysfunction, hearing loss and gastrointestinal disturbance should help prioritize genetic testing towards RRM2B analysis, and sequencing of the gene may preclude performance of a muscle biopsy

Enigmatic presence of mitochondrial complex I in Trypanosoma brucei bloodstream forms

The presence of mitochondrial respiratory complex I in the pathogenic bloodstream stages of Trypanosoma brucei has been vigorously debated: increased expression of mitochondrially encoded functional complex I mRNAs is countered by low levels of enzymatic activity that show marginal inhibition by the specific inhibitor rotenone. We now show that epitope-tagged versions of multiple complex I subunits assemble into α and β subcomplexes in the bloodstream stage and that these subcomplexes require the mitochondrial genome for their assembly. Despite the presence of these large (740- and 855-kDa) multisubunit complexes, the electron transport activity of complex I is not essential under experimental conditions since null mutants of two core genes (NUBM and NUKM) showed no growth defect in vitro or in mouse infection. Furthermore, the null mutants showed no decrease in NADH:ubiquinone oxidoreductase activity, suggesting that the observed activity is not contributed by complex I. This work conclusively shows that despite the synthesis and assembly of subunit proteins, the enzymatic function of the largest respiratory complex is neither significant nor important in the bloodstream stage. This situation appears to be in striking contrast to that for the other respiratory complexes in this parasite, where physical presence in a life-cycle stage always indicates functional significance