Mechanical properties of precast reinforced concrete slab tracks on non-ballasted foundations

AbstractThis article deals with the mechanical properties of steel-reinforced concrete precast slab tracks on non-ballasted elasto-plastic foundations. To work out the spanning behavior of slab tracks, a FEM analysis was executed for discrete and continuous systems. At first, full-size slabs without foundation including solid and hollow-core specimens (with 30% weight reduction) were tested under centric static (monotonic) line loads, and load–deflection curves were extracted. Then, FEM results for zero foundation stiffness were verified with those of experiments, which were in good agreement. Original results include the effects of several parameters on the cracking load, ultimate load, and energy absorption of slabs placed on elasto-plastic foundations including the slab width, concrete tensile strength and load factor. Analyses revealed that mechanical properties in hollow-core sections are not so different from those in solid ones, and thus hollow-core sections are more efficient because of significant weight reduction

PKD2 mutation in an Iranian autosomal dominant polycystic kidney disease family with misleading linkage analysis data

Background Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic renal disorder caused by mutation in 2 genes PKD1 and PKD2. Thus far, no mutation is identified in approximately 10 of ADPKD families, which can suggest further locus heterogeneity. Owing to the complexity of direct mutation detection, linkage analysis can initially identify the responsible gene in appropriate affected families. Here, we evaluated an Iranian ADPKD family apparently unlinked to both PKD1 and PKD2 genes. This is one of the pioneer studies in genetic analysis of ADPKD in Iranian population. Methods Linkage reanalysis was performed by regenotyping of flanking microsatellite markers in 8 individuals of the ADPKD family. Direct mutation analysis was performed by Sanger sequencing. Results Mutation analysis revealed a pathogenic mutation (c.1094+1G>A) in the PKD2 gene in the proband. Analyzing 2 healthy and 4 clinically affected members confirmed the correct segregation of the mutation within the family and also ruled out the disease in 1 suspected individual. Misinterpretation of the linkage data was due to the occurrence of 1 crossing over between the PKD2 intragenic and the nearest downstream marker (D4S2929). Homozygosity of upstream markers caused the recombination indistinguishable. Conclusion Although analysis of additive informative polymorphic markers can overcome the misleading haplotype data, it is limited because of the lack of other highly polymorphic microsatellite markers closer to the gene. Direct mutation screening can identify the causative mutation in the apparently unlinked pedigree; moreover, it is the only approach to achieve the confirmed diagnosis in individuals with equivocal imaging results. © 2016. The Korean Society of Nephrology. Published by Elsevier

An efficient trio-based mini-haplotyping method for genetic diagnosis of phenylketonuria

Objective: The phenylalanine hydroxylase (PAH) locus has high linkage disequilibrium. Haplotypes related to this locus may thus be considered sufficiently informative for genetic diagnosis and carrier screening using multi-allelic markers. In this study, we present an efficient method for haplotype analysis of PAH locus using multiplexing dyes. In addition, we explain how to resolve the dye shift challenge in multiplex short tandem repeat (STR) genotyping. Materials and Methods: One hundred family trios were included in this descriptive study. The forward primer of a tetra-nucleotide STR and the reverse primer of a variable number tandem repeat (VNTR) were labeled with three different non-overlapping dyes 5-carboxyfluorescein (FAM), 6-carboxy-N,N,N�,N�-tetramethylrhodamine (HEX) and 6-carboxy-N,N,N�,N�-tetramethylrhodamine (TAMRA). The polymerase chain reaction (PCR) products from each family trio were multiplexed for capillary electrophoresis and results were analyzed using Peak Scanner software. Results: Multiplexing trio products decreased the cost significantly. The TAMRA labeled products had a significant predictable shift (migrated at a slower electrophoretic rate) relative to the HEX and FAM labeled products. Through our methodology we achieve, the less inter-dye shift than intra-dye shift variance. Correcting the dye shift in the labeled products, according to the reference allele size, significantly decreased the inter-dye variability (P<0.001). Conclusion: Multiplexing trio products helps to detect and resolve the dye shift accurately in each family, which otherwise would result in diagnostic error. The dye system of FAM, HEX and TAMRA is more feasible and cheaper than other dye systems

Histone deacetylases suppress cgg repeat-induced neurodegeneration via transcriptional silencing in models of Fragile X Tremor Ataxia Syndrome

Fragile X Tremor Ataxia Syndrome (FXTAS) is a common inherited neurodegenerative disorder caused by expansion of a CGG trinucleotide repeat in the 59UTR of the fragile X syndrome (FXS) gene, FMR1. The expanded CGG repeat is thought to induce toxicity as RNA, and in FXTAS patients mRNA levels for FMR1 are markedly increased. Despite the critical role of FMR1 mRNA in disease pathogenesis, the basis for the increase in FMR1 mRNA expression is unknown. Here we show that overexpressing any of three histone deacetylases (HDACs 3, 6, or 11) suppresses CGG repeat-induced neurodegeneration in a Drosophila model of FXTAS. This suppression results from selective transcriptional repression of the CGG repeat-containing transgene. These findings led us to evaluate the acetylation state of histones at the human FMR1 locus. In patient-derived lymphoblasts and fibroblasts, we determined by chromatin immunoprecipitation that there is increased acetylation of histones at the FMR1 locus in pre-mutation carriers compared to control or FXS derived cell lines. These epigenetic changes correlate with elevated FMR1 mRNA expression in pre-mutation cell lines. Consistent with this finding, histone acetyltransferase (HAT) inhibitors repress FMR1 mRNA expression to control levels in pre-mutation carrier cell lines and extend lifespan in CGG repeat-expressing Drosophila. These findings support a disease model whereby the CGG repeat expansion in FXTAS promotes chromatin remodeling in cis, which in turn increases expression of the toxic FMR1 mRNA. Moreover, these results provide proof of principle that HAT inhibitors or HDAC activators might be used to selectively repress transcription at the FMR1 locus.open293

Use of model systems to understand the etiology of fragile X-associated primary ovarian insufficiency (FXPOI)

Fragile X-associated primary ovarian insufficiency (FXPOI) is among the family of disorders caused by the expansion of a CGG repeat sequence in the 5' untranslated region of the X-linked gene FMR1. About 20% of women who carry the premutation allele (55 to 200 unmethylated CGG repeats) develop hypergonadotropic hypogonadism and cease menstruating before age 40. Some proportion of those who are still cycling show hormonal profiles indicative of ovarian dysfunction. FXPOI leads to subfertility and an increased risk of medical conditions associated with early estrogen deficiency. Little progress has been made in understanding the etiology of this clinically significant disorder. Understanding the molecular mechanisms of FXPOI requires a detailed knowledge of ovarian FMR1 mRNA and FMRP’s function. In humans, non-invasive methods to discriminate the mechanisms of the premutation on ovarian function are not available, thus necessitating the development of model systems. Vertebrate (mouse and rat) and invertebrate (Drosophila melanogaster) animal studies for the FMR1 premutation and ovarian function exist and have been instrumental in advancing our understanding of the disease phenotype. For example, rodent models have shown that FMRP is highly expressed in oocytes where it is important for folliculogenesis. The two premutation mouse models studied to date show evidence of ovarian dysfunction and, together, suggest that the long repeat in the transcript itself may have some pathological effect quite apart from any effect of the toxic protein. Further, ovarian morphology in young animals appears normal and the primordial follicle pool size does not differ from that of wild-type animals. However, there is a progressive premature decline in the levels of most follicle classes. Observations also include granulosa cell abnormalities and altered gene expression patterns. Further comparisons of these models are now needed to gain insight into the etiology of the ovarian dysfunction. Premutation model systems in non-human primates and those based on induced pluripotent stem cells show particular promise and will complement current models. Here, we review the characterization of the current models and describe the development and potential of the new models. Finally, we will discuss some of the molecular mechanisms that might be responsible for FXPOI

Multi affected pedigree with congenital microcephaly: WES revealed PNKP gene mutation

Microcephaly is a rare neurological disorder, occurs in both isolated and syndromic forms. This classification could be confusing in rare disorders with variable phenotypic characteristics. However, identification of the causative gene through genetic study would allow determining the definite diagnosis. Here we reported a novel missense variant c.1133A>C (p.Lys378Thr) on the 13th exon of PNKP gene identified by whole exome sequencing (WES) in an Iranian multi-affected family with microcephaly, seizures and developmental delay (MCSZ) disorder. Data analysis suggested this variant as a pathogenic mutation which is co-segregate with the disease in the pedigree. PNKP gene mutation is consistent with the clinical features of the affected family members. Regarding both genetic findings and clinical examinations, the reported pedigree can be considered as another affected family with MCSZ syndrome, which has been reported about 10 cases worldwide. This study proves the application of WES for determining the final diagnosis in complicated neurodevelopmental disorders. © 2018 The Japanese Society of Child Neurolog

The individual or combinational effects of Hesperetin and Letrozole on the activity and expression of aromatase in MCF-7 cells

Aromatase catalyzes the last and rate-limiting step in estrogen biosynthesis. Inhibition of estrogen production is a common strategy for breast cancer treatment. Citrus flavonoids have been confirmed to exhibit efficacious biological activities, particularly in cancer therapy. This study was carried out to investigate the effect of hesperetin on the activity and expression of aromatase and compare this property with letrozole as an aromatase inhibitor in MCF-7 breast cancer cell line. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assays in this study demonstrated that hesperetin at a concentration of 200 μM decreased cell viability in a time dependent manner (P < 0.05). Aromatase activity assay, based on 17β-Estradiol (E2) production from testosterone, revealed that hesperetin had no effect. Real-time PCR results indicated that treatment with 1μM concentration of hesperetin for 48 h significantly decreased relative aromatase expression (P =0.004). Combination of letrozole and hesperetin also had no effect on aromatase. The changes in activity paralleled the expression of aromatase. Likely, the reduction in aromatase activity was delayed in time along with the reduction in expression ratio; however additional studies are needed to confirm this. In conclusion, the present study showed that hesperetin could decrease expression of aromatase at low concentrations in MCF-7 breast cancer cells. © 2016 by the C.M.B. Association. All rights reserved