Statistical Model for the Mechanical Properties of Al-Cu-Mg-Ag Alloys at High Temperatures

Aluminum alloys for high-temperature applications have been the focus of many investigations lately. The main concern in such alloys is to maintain mechanical properties during operation at high temperatures. Grain coarsening and instability of precipitates could be the main reasons behind mechanical strength deterioration in these applications. Therefore, Al-Cu-Mg-Ag alloys were proposed for such conditions due to the high stability of Ω precipitates. Four different compositions of Al-Cu-Mg-Ag alloys, designed based on half-factorial design, were cast, homogenized, hot-rolled, and isothermally aged for different durations. The four alloys were tensile-tested at room temperature as well as at 190 and 250°C at a constant initial strain rate of 0.001 s−1, in two aging conditions, namely, underaged and peak-aged. The alloys demonstrated good mechanical properties at both aging times. However, underaged conditions displayed better thermal stability. Statistical models, based on fractional factorial design of experiments, were constructed to relate the experiments output (yield strength and ultimate tensile strength) with the studied process parameters, namely, tensile testing temperature, aging time, and copper, magnesium, and silver contents. It was shown that the copper content had a great effect on mechanical properties. Also, more than 80% of the variation of the high-temperature data was explained through the generated statistical models

Abstract 5444: Real-time RT-PCR of terminal deoxynucleotidyl transferase (TdT) is a useful tool for identification of minimal leukemia in cerebrospinal fluid

Accurate detection of central nervous system (CNS) involvement in children with newly diagnosed acute lymphoblastic leukemia (ALL) could have profound prognostic and therapeutic implications. The detection of cerebrospinal fluid (CSF) infiltration by leukemic cells as performed by morphological assessment is subjective and unable to detect low levels of involvement. Therefore, newer and more accurate techniques are required to more efficiently detect minimal leukemic cell involvement. For this reason, a quantitative, Real-time RT-PCR targeting the TdT molecule was developed and tested to allow an objective and sensitive methodology for detecting CNS leukemia. 35 diagnostic CSF samples were subjected to the qRT-PCR assay for TdT. Only 4/35 samples were positive by cytomorphological detection. Of these 4 samples, one sample was diagnosed with CNS disease (CNS 3) and three samples had lower numbers of leukemic blasts (CNS 2). When compared to morphology results, as the gold standard, we found 24 out of the 35 samples to be positive by qRT-PCR. 20 CSF samples that were negative by morphology had detectable TdT by RT-PCR, possibly indicating leukemic infiltration below the level of cytomorphological detection. Serial samples for the 4 CNS-positive patients were tested by qRT-PCR and showed persistent positivity with gradual reduction in quantity of TdT with chemotherapy administration. 11 samples had no detectable TdT by RT-PCR and were found to be negative by cytomorphological assessment as well. In patients with no cytomorphologically detected blasts, TdT positivity was not associated with the level of peripheral blood WBC count. This methodology provides an objective, quantitative and sensitive tool for the detection of leukemic blasts in the CSF. This allows us to detect molecular CNS involvement in CNS negative patients. Although the outcome for all CNS negative patients is good, this has been achieved with fairly intensive prophylactic CNS-directed therapy, reduction in CNS-directed therapy may be possible in molecularly negative patients

Bortezomib inhibits proteasomal degradation of IκBα and induces mitochondrial dependent apoptosis in activated B-cell diffuse large B-cell lymphoma

Activated B-cell type lymphoma (ABC), a subgroup of diffuse large B-cell lymphoma (DLBCL), has a worse survival after upfront chemotherapy and is characterized by constitutive activation of the anti-apoptotic nuclear factor-κB (NFκB) pathway. The implication of NFκB inhibition in ABC has not yet been fully explored as a potential therapeutic target. Therefore, a panel of ABC cell lines was used to examine the effect of bortezomib, a proteasome inhibitor which blocks degradation of IκBα and consequently inhibits NFκB activity. Our data showed that bortezomib caused a dose-dependent growth inhibition and induction of apoptosis in all cell lines studied. We next determined the status of the NFκB pathway following bortezomib treatment and found that there was accumulation of IκBα without affecting its phosphorylation status at an early time point. Electrophoretic mobility shift assay showed that bortezomib treatment inhibited constitutive nuclear NFκB in ABC cell lines. Furthermore, treatment of ABC cell lines with bortezomib for 48 h also down-regulated the expression of NFκB-regulated gene products, such as IκBα, Bcl-2, Bcl-Xl, XIAP and survivin, leading to apoptosis via the mitochondrial apoptotic pathway. Altogether, these results suggest that NFκB may be a potential target for therapeutic intervention in DLBCL using proteasomal inhibitors such as bortezomib

POLE and POLD1 germline exonuclease domain pathogenic variants, a rare event in colorectal cancer from the Middle East

Abstract Background Colorectal cancer (CRC) is a major contributor to morbidity and mortality related to cancer. Only ~5% of all CRCs occur as a result of pathogenic variants in well‐defined CRC predisposing genes. The frequency and effect of exonuclease domain pathogenic variants of POLE and POLD1 genes in Middle Eastern CRCs is still unknown. Methods Targeted capture sequencing and Sanger sequencing technologies were employed to investigate the germline exonuclease domain pathogenic variants of POLE and POLD1 in Middle Eastern CRCs. Immunohistochemical analysis of POLE and POLD1 was performed to look for associations between protein expression and clinico‐pathological characteristics. Results Five damaging or possibly damaging variants (0.44%) were detected in 1,135 CRC cases, four in POLE gene (0.35%, 4/1,135) and one (0.1%, 1/1,135) in POLD1 gene. Furthermore, low POLE protein expression was identified in 38.9% (417/1071) cases and a significant association with lymph node involvement (p = .0184) and grade 3 tumors (p = .0139) was observed. Whereas, low POLD1 expression was observed in 51.9% (555/1069) of cases and was significantly associated with adenocarcinoma histology (p = .0164), larger tumor size (T3 and T4 tumors; p = .0012), and stage III tumors (p = .0341). Conclusion POLE and POLD1 exonuclease domain pathogenic variants frequency in CRC cases was very low and these exonuclease domain pathogenic variants might be rare causative events of CRC in the Middle East. POLE and POLD1 can be included in multi‐gene panels to screen CRC patients

Clonal Evolution and Timing of Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third most frequently diagnosed cancer worldwide, where ~50% of patients develop metastasis, despite current improved management. Genomic characterisation of metastatic CRC, and elucidating the effects of therapy on the metastatic process, are essential to help guide precision medicine. Multi-region whole-exome sequencing was performed on 191 sampled tumour regions of patient-matched therapy-naïve and treated CRC primary tumours (n = 92 tumour regions) and metastases (n = 99 tumour regions), in 30 patients. Somatic variants were analysed to define the origin, composition, and timing of seeding in the metastatic progression of therapy-naïve and treated metastatic CRC. High concordance, with few genomic differences, was observed between primary CRC and metastases. Most cases supported a late dissemination model, via either monoclonal or polyclonal seeding. Polyclonal seeding appeared more common in therapy-naïve metastases than in treated metastases. Whereby, treatment prompted for the selection of distinct resistant clones, through monoclonal seeding to distant metastatic sites. Overall, this study reinforces the importance of early clinical detection and surgical excision of the CRC tumour, whilst further highlighting the clinical challenges for metastatic CRC with increased intratumour heterogeneity (either due to early dissemination or polyclonal metastatic spread) and the underlying risk of future therapeutic resistance in treated patients

Mutation in LIM2 Is Responsible for Autosomal Recessive Congenital Cataracts.

To identify the molecular basis of non-syndromic autosomal recessive congenital cataracts (arCC) in a consanguineous family.All family members participating in the study received a comprehensive ophthalmic examination to determine their ocular phenotype and contributed a blood sample, from which genomic DNA was extracted. Available medical records and interviews with the family were used to compile the medical history of the family. The symptomatic history of the individuals exhibiting cataracts was confirmed by slit-lamp biomicroscopy. A genome-wide linkage analysis was performed to localize the disease interval. The candidate gene, LIM2 (lens intrinsic membrane protein 2), was sequenced bi-directionally to identify the disease-causing mutation. The physical changes caused by the mutation were analyzed in silico through homology modeling, mutation and bioinformatic algorithms, and evolutionary conservation databases. The physiological importance of LIM2 to ocular development was assessed in vivo by real-time expression analysis of Lim2 in a mouse model.Ophthalmic examination confirmed the diagnosis of nuclear cataracts in the affected members of the family; the inheritance pattern and cataract development in early infancy indicated arCC. Genome-wide linkage analysis localized the critical interval to chromosome 19q with a two-point logarithm of odds (LOD) score of 3.25. Bidirectional sequencing identified a novel missense mutation, c.233G>A (p.G78D) in LIM2. This mutation segregated with the disease phenotype and was absent in 192 ethnically matched control chromosomes. In silico analysis predicted lower hydropathicity and hydrophobicity but higher polarity of the mutant LIM2-encoded protein (MP19) compared to the wild-type. Moreover, these analyses predicted that the mutation would disrupt the secondary structure of a transmembrane domain of MP19. The expression of Lim2, which was detected in the mouse lens as early as embryonic day 15 (E15) increased after birth to a level that was sustained through the postnatal time points.A novel missense mutation in LIM2 is responsible for autosomal recessive congenital cataracts

Correction: Deletion at the GCNT2 Locus Causes Autosomal Recessive Congenital Cataracts.

[This corrects the article DOI: 10.1371/journal.pone.0167562.]

Deletion at the GCNT2 Locus Causes Autosomal Recessive Congenital Cataracts.

The aim of this study is to identify the molecular basis of autosomal recessive congenital cataracts (arCC) in a large consanguineous pedigree.All participating individuals underwent a detailed ophthalmic examination. Each patient's medical history, particularly of cataracts and other ocular abnormalities, was compiled from available medical records and interviews with family elders. Blood samples were donated by all participating family members and used to extract genomic DNA. Genetic analysis was performed to rule out linkage to known arCC loci and genes. Whole-exome sequencing libraries were prepared and paired-end sequenced. A large deletion was found that segregated with arCC in the family, and chromosome walking was conducted to estimate the proximal and distal boundaries of the deletion mutation.Exclusion and linkage analysis suggested linkage to a region of chromosome 6p24 harboring GCNT2 (glucosaminyl (N-acetyl) transferase 2) with a two-point logarithm of odds score of 5.78. PCR amplifications of the coding exons of GCNT2 failed in individuals with arCC, and whole-exome data analysis revealed a large deletion on chromosome 6p in the region harboring GCNT2. Chromosomal walking using multiple primer pairs delineated the extent of the deletion to approximately 190 kb. Interestingly, a failure to amplify a junctional fragment of the deletion break strongly suggests an insertion in addition to the large deletion.Here, we report a novel insertion/deletion mutation at the GCNT2 locus that is responsible for congenital cataracts in a large consanguineous family

Primer sequences for the confirmation of <i>GCNT2</i> deletion breakpoints in PKCC215.

<p>Primer sequences for the confirmation of <i>GCNT2</i> deletion breakpoints in PKCC215.</p

Expression profile of lens intrinsic membrane protein 2 (<i>Lim2</i>) in the developing mouse lens.

<p>The expression of <i>Lim2</i> at different developmental time points was normalized to <i>Gapdh</i>. The x-axis and y-axis represent developmental time points and normalized expression of <i>Lim2</i> mRNA, respectively.</p