761 resultados para 1077


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Breast carcinoma, one of the most frequent malignancies in women, is a complex disease in which a number of different factors combine to drive pathogenesis. The biopathological characterization of these tumors is essential to determine their aggressiveness and to find the most appropriate therapy. As in others neoplasms, the deregulation of signal transduction pathways is frequently responsible for conferring selective biological advantages to the tumor. Phosphoinositides play an essential role in diverse cellular functions, their metabolism is highly active, and is tightly controlled. Among the enzymes implicated in this pathway, phospholipase C beta 1 (PLCβ1) is one of the key regulators, both at the cytoplasmic and the nuclear level. The PLCβ1 gene maps onto the short arm of chromosome 20, a region that has been shown to be altered in several solid tumors, including breast cancer. In the present study a FISH approach was used to investigate the genetic alterations of the PLCβ1 gene in various classes of breast cancer which differ in their invasiveness and proliferation status, according to their mitotic index. The overall aim was to find out whether this enzyme could be a suitable prognostic marker for this neoplasm. Our results show that 83% of cases had aneusomies at the 20p12 level, and the most frequent alteration is a gain in this specific locus. Indeed, we found that this amplification is not related to the invasion status since there were no differences in amplified tumor frequencies between in situ and invasive breast cancer. On the contrary, the gain of PLCβ1 was significantly related to the mitotic index (p = 0.001). To verify if the change in genetic dosage influences the expression of PLCβ1 we performed Real Time PCR and Immunohystochemical analysis. Our results confirmed that amplified tumors have higher levels of PLCβ1 mRNA, which is the sum of the two splicing isoforms 1a and 1b. On the other hand, even if protein levels were higher in the majority of cases compared to the nontumoral specimens, there were no significant associations between gain and overexpression. Finally, the significant association between the amplification of PLCβ1 and others important clinicopathological parameters, such as grading and hormonal receptors status, confirmed a correlation of this enzyme with the aggressiveness of breast cancer. This suggests that PLCβ1 has the potential to be a prognostic marker in these tumors. However, further work needs to be carried out to validate these preliminary findings.

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Quantitative branch determination in polyolefins by solid- and melt-state 13C NMR has been investigated. Both methods were optimised toward sensitivity per unit time. While solid-state NMR was shown to give quick albeit only qualitative results, melt-state NMR allowed highly time efficient accurate branch quantification. Comparison of spectra obtained using spectrometers operating at 300, 500 and 700 MHz 1H Larmor frequency, with 4 and 7~mm MAS probeheads, showed that the best sensitivity was achieved at 500 MHz using a 7 mm 13C-1H optimised high temperature probehead. For materials available in large quantities, static melt-state NMR, using large diameter detection coils and high coil filling at 300 MHz, was shown to produce comparable results to melt-state MAS measurements in less time. While the use of J-coupling mediated polarisation transfer techniques was shown to be possible, direct polarisation via single-pulse excitation proved to be more suitable for branch quantification in the melt-state. Artificial line broadening, introduced by FID truncation, was able to be reduced by the use of π pulse-train heteronuclear dipolar decoupling. This decoupling method, when combined with an extended duty-cycle, allowed for significant improvement in resolution. Standard setup, processing and analysis techniques were developed to minimise systematic errors contributing to the measured branch contents. The final optimised melt-state MAS NMR method was shown to allow time efficient quantification of comonomer content and distribution in both polyethylene- and polypropylene-co-α-olefins. The sensitivity of the technique was demonstrated by quantifying branch concentrations of 8 branches per 100,000 CH2 for an industrial ‘linear’ polyethylene in only 13 hours. Even lower degrees of 3–8 long-chain branches per 100,000 carbons were able to be estimated in just 24 hours for a series of γ-irradiated polypropylene homopolymers.

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Malignant rhabdoid tumor (MRT) of the liver is a rare malignancy with grave prognosis. This entity should be considered in the differential diagnosis of any aggressive liver tumor with low levels of alpha fetoprotein. We report 2 cases of hepatic MRT presenting in infancy. In these 2 cases, we show that loss of INI1 facilitates making the correct diagnosis of primary hepatic MRT utilizing BAF 47 (INI1 gene product) immunostains. Difficulty encountered in making this rare diagnosis, including the need for repeated biopsies, can be avoided if MRT is considered in the differential diagnosis early on and BAF 47 immunohistochemistry is ordered.

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Attempting to achieve the high diversity of training goals in modern competitive alpine skiing simultaneously can be difficult and may lead to compromised overall adaptation. Therefore, we investigated the effect of block training periodization on maximal oxygen consumption (VO2max) and parameters of exercise performance in elite junior alpine skiers. Six female and 15 male athletes were assigned to high-intensity interval (IT, N = 13) or control training groups (CT, N = 8). IT performed 15 high-intensity aerobic interval (HIT) sessions in 11 days. Sessions were 4 x 4 min at 90-95% of maximal heart rate separated by 3-min recovery periods. CT continued their conventionally mixed training, containing endurance and strength sessions. Before and 7 days after training, subjects performed a ramp incremental test followed by a high-intensity time-to-exhaustion (tlim) test both on a cycle ergometer, a 90-s high-box jump test as well as countermovement (CMJ) and squat jumps (SJ) on a force plate. IT significantly improved relative VO2max by 6.0% (P < 0.01; male +7.5%, female +2.1%), relative peak power output by 5.5% (P < 0.01) and power output at ventilatory threshold 2 by 9.6% (P < 0.01). No changes occurred for these measures in CT. tlim remained unchanged in both groups. High-box jump performance was significantly improved in males of IT only (4.9%, P < 0.05). Jump peak power (CMJ -4.8%, SJ -4.1%; P < 0.01), but not height decreased in IT only. For competitive alpine skiers, block periodization of HIT offers a promising way to efficiently improve VO2max and performance. Compromised explosive jump performance might be associated with persisting muscle fatigue.

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Protein is an essential component for life, and its synthesis is mediated by codons in any organisms on earth. While some codons encode the same amino acid, their usage is often highly biased. There are many factors that can cause the bias, but a potential effect of mononucleotide repeats, which are known to be highly mutable, on codon usage and codon pair preference is largely unknown. In this study we performed a genomic survey on the relationship between mononucleotide repeats and codon pair bias in 53 bacteria, 68 archaea, and 13 eukaryotes. By distinguishing the codon pair bias from the codon usage bias, four general patterns were revealed: strong avoidance of five or six mononucleotide repeats in codon pairs; lower observed/expected (o/e) ratio for codon pairs with C or G repeats (C/G pairs) than that with A or T repeats (A/T pairs); a negative correlation between genomic GC contents and the o/e ratios, particularly for C/G pairs; and avoidance of C/G pairs in highly conserved genes. These results support natural selection against long mononucleotide repeats, which could induce frameshift mutations in coding sequences. The fact that these patterns are found in all kingdoms of life suggests that this is a general phenomenon in living organisms. Thus, long mononucleotide repeats may play an important role in base composition and genetic stability of a gene and gene functions.

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Short QT syndrome (SQTS) is a genetically determined ion-channel disorder, which may cause malignant tachyarrhythmias and sudden cardiac death. Thus far, mutations in five different genes encoding potassium and calcium channel subunits have been reported. We present, for the first time, a novel loss-of-function mutation coding for an L-type calcium channel subunit.

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The aim of my thesis is to chart how death and the spirit world - what might be defined as our living essence - becomes the sites of a new and remarkably subversive Victorian exploration of the supernatural.

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INTRODUCTION: Acute fibrinous and organizing pneumonia (AFOP) is a recently described histologic pattern of diffuse pulmonary disease. In children, all cases reported to date have been fatal. In this study, we describe the first nonfatal AFOP in a child and review the literature. DESCRIPTION: A 10-year-old boy developed very severe aplastic anemia (VSAA) after being admitted to our hospital with a fulminant hepatic failure of unknown origin. A chest computed tomography scan revealed multiple lung nodules and a biopsy of a pulmonary lesion showed all the signs of AFOP. Infectious workup remained negative. We started immunosuppressive therapy with antithymocyte globulin and cyclosporine to treat VSAA. Subsequent chest computed tomography scans showed a considerable diminution of the lung lesions but the VSAA did not improve until we performed hematopoietic stem cell transplantation 5 months later. CONCLUSIONS: Aplastic anemia is associated with a variety of autoimmune syndromes. The sequence of events in our patient suggests that the hepatic failure, AFOP, and the VSAA may all have been part of an autoimmune syndrome. AFOP could be the result of immune dysregulation in this pediatric case with favorable outcome after immunosuppressive therapy and hematopoietic stem cell transplantation.

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Many children with sarcomas undergo whole body 2-deoxy-2-((18)F)fluoro-D-glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) and technetium methylene diphosphonate ((99)Tc-MDP) studies. It is unknown whether the combination of both tests results in more accurate detection of bone lesions than (18)F-FDG- PET/CT alone.