457 research outputs found

    Increased Expression of System x_c^- in Glioblastoma Confers an Altered Metabolic State and Temozolomide Resistance

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    Glioblastoma multiforme is the most aggressive malignant primary brain tumor in adults. Several studies have shown that glioma cells upregulate the expression of xCT (SLC7A11), the catalytic subunit of system x_c^-, a transporter involved in cysteine import, that modulates glutathione production and glioma growth. However, the role of system x_c^- in regulating the sensitivity of glioma cells to chemotherapy is currently debated. Inhibiting system x_c^- with sulfasalazine decreased glioma growth and survival via redox modulation, and use of the chemotherapeutic agent temozolomide together with sulfasalazine had a synergistic effect on cell killing. To better understand the functional consequences of system x_c^- in glioma, stable SLC7A11-knockdown and -overexpressing U251 glioma cells were generated. Modulation of SLC7A11 did not alter cellar proliferation but overexpression did increase anchorage-independent cell growth. Knockdown of SLC7A11 increased basal reactive oxygen species (ROS) and decreased glutathione generation resulting in increased cell death under oxidative and genotoxic stress. Overexpression of SLC7A11 resulted in increased resistance to oxidative stress and decreased chemosensitivity to temozolomide. In addition, SLC7A11 overexpression was associated with altered cellular metabolism including increased mitochondrial biogenesis, oxidative phosphorylation, and ATP generation. These results suggest that expression of SLC7A11 in the context of glioma contributes to tumorigenesis, tumor progression, and resistance to standard chemotherapy

    Boundary Layer Transition Results From STS-114

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    The tool for predicting the onset of boundary layer transition from damage to and/or repair of the thermal protection system developed in support of Shuttle Return to Flight is compared to the STS-114 flight results. The Boundary Layer Transition (BLT) Tool is part of a suite of tools that analyze the aerothermodynamic environment of the local thermal protection system to allow informed disposition of damage for making recommendations to fly as is or to repair. Using mission specific trajectory information and details of each damage site or repair, the expected time of transition onset is predicted to help determine the proper aerothermodynamic environment to use in the subsequent thermal and stress analysis of the local structure. The boundary layer transition criteria utilized for the tool was developed from ground-based measurements to account for the effect of both protuberances and cavities and has been calibrated against flight data. Computed local boundary layer edge conditions provided the means to correlate the experimental results and then to extrapolate to flight. During STS-114, the BLT Tool was utilized and was part of the decision making process to perform an extravehicular activity to remove the large gap fillers. The role of the BLT Tool during this mission, along with the supporting information that was acquired for the on-orbit analysis, is reviewed. Once the large gap fillers were removed, all remaining damage sites were cleared for reentry as is. Post-flight analysis of the transition onset time revealed excellent agreement with BLT Tool predictions

    Biosynthesis of Mitochondrial Porin and Insertion into the Outer Mitochondrial Membrane of Neuruspora crassa

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    Mitochondrial porin, the major protein of the outer mitochondrial membrane is synthesized by free cytoplasmic polysomes. The apparent molecular weight of the porin synthesized in homologous or heterologous cell-free systems is the same as that of the mature porin. Transfer in vitro of mitochondrial porin from the cytosolic fraction into the outer membrane of mitochondria could be demonstrated. Before membrane insertion, mitochondrial porin is highly sensitive to added proteinase; afterwards it is strongly protected. Binding of the precursor form to mitochondria occurs at 4°C and appears to precede insertion into the membrane. Unlike transfer of many precursor proteins into or across the inner mitochondrial membrane, assembly of the porin is not dependent on an electrical potential across the inner membrane

    Whole-genome SNP association analysis of reproduction traits in the Finnish Landrace pig breed

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    <p>Abstract</p> <p>Background</p> <p>Good genetic progress for pig reproduction traits has been achieved using a quantitative genetics-based multi-trait BLUP evaluation system. At present, whole-genome single nucleotide polymorphisms (SNP) panels provide a new tool for pig selection. The purpose of this study was to identify SNP associated with reproduction traits in the Finnish Landrace pig breed using the Illumina PorcineSNP60 BeadChip.</p> <p>Methods</p> <p>Association of each SNP with different traits was tested with a weighted linear model, using SNP genotype as a covariate and animal as a random variable. Deregressed estimated breeding values of the progeny tested boars were used as the dependent variable and weights were based on their reliabilities. Statistical significance of the associations was based on Bonferroni-corrected <it>P</it>-values.</p> <p>Results</p> <p>Deregressed estimated breeding values were available for 328 genotyped boars. Of the 62 163 SNP in the chip, 57 868 SNP had a call rate > 0.9 and 7 632 SNP were monomorphic. Statistically significant results (<it>P</it>-value < 2.0E-06) were obtained for total number of piglets born in first and later parities and piglet mortality between birth and weaning in later parity, and suggestive associations (<it>P</it>-value < 4.0E-06) for piglet mortality between birth and weaning in first parity, number of stillborn piglets in later parity, first farrowing interval and second farrowing interval. Two of the statistically significant regions for total number of piglets born in first and later parities are located on chromosome 9 around 95 and 79 Mb. The estimated SNP effect in these regions was approximately one piglet between the two homozygote classes. By combining the two most significant SNP in these regions, favourable double homozygote animals are expected to have 1.3 piglets (<it>P</it>-value = 1.69E-08) more than unfavourable double homozygote animals. A region on chromosome 9 (66 Mb) was statistically significant for piglet mortality between birth and weaning in later parity (0.44 piglets between homozygotes, <it>P</it>-value = 6.94E-08).</p> <p>Conclusions</p> <p>Three separate regions on chromosome 9 gave significant results for litter size and pig mortality. The frequencies of favourable alleles of the significant SNP are moderate in the Finnish Landrace population and these SNP are thus valuable candidates for possible marker-assisted selection.</p

    Ophthalmic Artery Chemosurgery for Less Advanced Intraocular Retinoblastoma: Five Year Review

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    BACKGROUND: Ophthalmic artery chemosurgery (OAC) for retinoblastoma was introduced by us 5 years ago for advanced intraocular retinoblastoma. Because the success was higher than with existing alternatives and systemic side effects limited we have now treated less advanced intraocular retinoblastoma (Reese-Ellsworth (RE) I-III and International Classification Retinoblastoma (ICRB) B and C). METHODOLOGY/PRINCIPAL FINDINGS: Retrospective review of 5 year experience in eyes with Reese Ellsworth (Table 1) I (7 eyes), II (6 eyes) or III (6 eyes) and/or International Classification (Table 2) B (19 eyes) and C (11 eyes) treated with OAC (melphalan with or without topotecan) introduced directly into the ophthalmic artery. Patient survival was 100%. Ocular event-free survival was 100% for Reese-Ellsworth Groups I, II and III (and 96% for ICRB B and C) at a median of 16 months follow-up. One ICRB Group C (Reese-Ellsworth Vb) eye could not be treated on the second attempt for technical reasons and was therefore enucleated. No patient required a port and only one patient required transfusion of blood products. The electroretinogram (ERG) was unchanged or improved in 14/19 eyes. CONCLUSIONS/SIGNIFICANCE: Ophthalmic artery chemosurgery for retinoblastoma that was Reese-Ellsworth I, II and III (or International Classification B or C) was associated with high success (100% of treatable eyes were retained) and limited toxicity with results that equal or exceed conventional therapy with less toxicity

    Stereotactic body radiation therapy with or without transarterial chemoembolization for patients with primary hepatocellular carcinoma: preliminary analysis

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    <p>Abstract</p> <p>Background</p> <p>The objectives of this retrospective study was to evaluate the efficacy of stereotactic body radiation therapy (SBRT) for small non-resectable hepatocellular carcinoma (HCC) and SBRT combined with transarterial chemoembolization (TACE) for advanced HCC with portal vein tumor thrombosis (PVTT).</p> <p>Methods</p> <p>Thirty one patients with HCC who were treated with SBRT were used for the study. We studied 32 HCC lesions, where 23 lesions (22 patients) were treated targeting small non-resectable primary HCC, and 9 lesions (9 patients) targeting PVTT using the Cyberknife. All the 9 patients targeting PVTT received TACE for the advanced HCC. Tumor volume was 3.6–57.3 cc (median, 25.2 cc) and SBRT dose was 30–39 Gy (median, 36 Gy) in 3 fractions for consecutive days for 70–85% of the planned target volume.</p> <p>Results</p> <p>The median follow up was 10.5 months. The overall response rate was 71.9% [small HCC: 82.6% (19/23), advanced HCC with PVTT: 44.4% (4/9)], with the complete and partial response rates of 31.3% [small HCC: 26.1% (6/23), advanced HCC with PVTT: 11.1% (1/9)], and 50.0% [small HCC: 56.5% (13/23), advanced HCC with PVTT: 33.3% (3/9)], respectively. The median survival period of small HCC and advanced HCC with PVTT patients was 12 months and 8 months, respectively. No patient experienced Grade 4 toxicity.</p> <p>Conclusion</p> <p>SBRT for small HCC and SBRT combined with TACE for advanced HCC with PVTT showed feasible treatment modalities with minimal side effects in selected patients with primary HCC.</p
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