Modelling neurofibromatosis type 1 tibial dysplasia and its treatment with lovastatin

<p>Abstract</p> <p>Background</p> <p>Bowing and/or pseudarthrosis of the tibia is a known severe complication of neurofibromatosis type 1 (NF1). Mice with conditionally inactivated neurofibromin (Nf1) in the developing limbs and cranium (Nf1Prx1) show bowing of the tibia caused by decreased bone mineralisation and increased bone vascularisation. However, in contrast to NF1 patients, spontaneous fractures do not occur in Nf1Prx1 mice probably due to the relatively low mechanical load. We studied bone healing in a cortical bone injury model in Nf1Prx1 mice as a model for NF1-associated bone disease. Taking advantage of this experimental model we explore effects of systemically applied lovastatin, a cholesterol-lowering drug, on the Nf1 deficient bone repair.</p> <p>Methods</p> <p>Cortical injury was induced bilaterally in the <it>tuberositas tibiae </it>in Nf1Prx1 mutant mice and littermate controls according to a method described previously. Paraffin as well as methacrylate sections were analysed from each animal. We divided 24 sex-matched mutant mice into a lovastatin-treated and an untreated group. The lovastatin-treated mice received 0.15 mg activated lovastatin by daily gavage. The bone repair process was analysed at three consecutive time points post injury, using histological methods, micro computed tomography measurements and <it>in situ </it>hybridisation. At each experimental time point, three lovastatin-treated mutant mice, three untreated mutant mice and three untreated control mice were analysed. The animal group humanely killed on day 14 post injury was expanded to six treated and six untreated mutant mice as well as six control mice.</p> <p>Results</p> <p>Bone injury repair is a complex process, which requires the concerted effort of numerous cell types. It is initiated by an inflammatory response, which stimulates fibroblasts from the surrounding connective tissue to proliferate and fill in the injury site with a provisional extracellular matrix. In parallel, mesenchymal progenitor cells from the periost are recruited into the injury site to become osteoblasts. In Nf1Prx1 mice bone repair is delayed and characterised by the excessive formation and the persistence of fibro-cartilaginous tissue and impaired extracellular matrix mineralisation. Correspondingly, expression of Runx2 is downregulated. High-dose systemic lovastatin treatment restores Runx2 expression and accelerates new bone formation, thus improving cortical bone repair in Nf1Prx1 tibia. The bone anabolic effects correlate with a reduction of the mitogen activated protein kinase pathway hyper-activation in Nf1-deficient cells.</p> <p>Conclusion</p> <p>Our data suggest the potential usefulness of lovastatin, a drug approved by the US Food and Drug Administration in 1987 for the treatment of hypercholesteraemia, in the treatment of Nf1-related fracture healing abnormalities. The experimental model presented here constitutes a valuable tool for the pre-clinical stage testing of candidate drugs, targeting Nf1-associated bone dysplasia.</p

Multiple Source Localization for Partial Discharge Monitoring in Electrical Substation

This paper studies novel localization methods of multiple partial discharge sources in electrical substations. The three compressive sensing algorithms of Orthogonal Matching Pursuit (OMP), Homotopy technique, and Dichotomous coordinate descent (DCD) are presented. The simulation results demonstrate excellent performance with the compressive sensing methods

Effects of concentration methods and storage conditions on some bioactive compounds and color of tamarind sorbet: a traditional Turkish beverage

In this study, the effects of concentration methods on the bioactivity properties of traditional tamarind sorbet were investigated. For this purpose, tamarind sorbet produced according to proper recipe were concentrated with three different methods such as conventional, microwave and vacuum heating and stored at 4, 20 and 37 A degrees C for 90 days. During the course of storage at 0th, 30th, 60th and 90th days, beside color parameters, some bioactivity properties such as; total phenolic content, total flavonoid content, antiradical and antioxidant activities were evaluated. Phenolic content of tamarind sorbet samples (0th and 90th day), concentrated with different methods and stored at different temperatures, was evaluated with LC-MS/MS. Protocatechuic acid and coumarin were found to be the major components of tamarind sorbet. It was determined that sorbet produced with vacuum method was rich in phenolic compounds compared to those produced with other methods. Total phenolic content was higher in the vacuum concentrated sample (1384.85 mg GAE/kg) followed by microwave (1354.55 mg GAE/kg) and conventional heating (1300 mg GAE/kg), respectively. Higher antioxidant activity (108.77 mg AAE/g) was determined in vacuum applied samples, its 0th day sample also contained higher phenolic content. Higher antiradical activity was detected in microwave sample with 70.1% inhibition. It was found that storage temperature and time was effective on the bioactive properties of tamarind sorbet. It was determined that vacuum method could be applied successfully to tamarind sorbet concentration especially when regarded threshold values, phenolic and flavonoid content and antioxidant properties

Prediction of Susceptibility to First-Line Tuberculosis Drugs by DNA Sequencing

&lt;p&gt;BACKGROUND: The World Health Organization recommends drug-susceptibility testing of Mycobacterium tuberculosis complex for all patients with tuberculosis to guide treatment decisions and improve outcomes. Whether DNA sequencing can be used to accurately predict profiles of susceptibility to first-line antituberculosis drugs has not been clear.METHODS: We obtained whole-genome sequences and associated phenotypes of resistance or susceptibility to the first-line antituberculosis drugs isoniazid, rifampin, ethambutol, and pyrazinamide for isolates from 16 countries across six continents. For each isolate, mutations associated with drug resistance and drug susceptibility were identified across nine genes, and individual phenotypes were predicted unless mutations of unknown association were also present. To identify how whole-genome sequencing might direct first-line drug therapy, complete susceptibility profiles were predicted. These profiles were predicted to be susceptible to all four drugs (i.e., pansusceptible) if they were predicted to be susceptible to isoniazid and to the other drugs or if they contained mutations of unknown association in genes that affect susceptibility to the other drugs. We simulated the way in which the negative predictive value changed with the prevalence of drug resistance.RESULTS: A total of 10,209 isolates were analyzed. The largest proportion of phenotypes was predicted for rifampin (9660 [95.4%] of 10,130) and the smallest was predicted for ethambutol (8794 [89.8%] of 9794). Resistance to isoniazid, rifampin, ethambutol, and pyrazinamide was correctly predicted with 97.1%, 97.5%, 94.6%, and 91.3% sensitivity, respectively, and susceptibility to these drugs was correctly predicted with 99.0%, 98.8%, 93.6%, and 96.8% specificity. Of the 7516 isolates with complete phenotypic drug-susceptibility profiles, 5865 (78.0%) had complete genotypic predictions, among which 5250 profiles (89.5%) were correctly predicted. Among the 4037 phenotypic profiles that were predicted to be pansusceptible, 3952 (97.9%) were correctly predicted.CONCLUSIONS: Genotypic predictions of the susceptibility of M. tuberculosis to first-line drugs were found to be correlated with phenotypic susceptibility to these drugs. (Funded by the Bill and Melinda Gates Foundation and others.).&lt;/p&gt;</p