Silencing of GATA3 defines a novel stem cell-like subgroup of ETP-ALL.

BACKGROUND: GATA3 is pivotal for the development of T lymphocytes. While its effects in later stages of T cell differentiation are well recognized, the role of GATA3 in the generation of early T cell precursors (ETP) has only recently been explored. As aberrant GATA3 mRNA expression has been linked to cancerogenesis, we investigated the role of GATA3 in early T cell precursor acute lymphoblastic leukemia (ETP-ALL). METHODS: We analyzed GATA3 mRNA expression by RT-PCR (n = 182) in adult patients with T-ALL. Of these, we identified 70 of 182 patients with ETP-ALL by immunophenotyping. DNA methylation was assessed genome wide (Illumina Infinium® HumanMethylation450 BeadChip platform) in 12 patients and GATA3-specifically by pyrosequencing in 70 patients with ETP-ALL. The mutational landscape of ETP-ALL with respect to GATA3 expression was investigated in 18 patients and validated by Sanger sequencing in 65 patients with ETP-ALL. Gene expression profiles (Affymetrix Human genome U133 Plus 2.0) of an independent cohort of adult T-ALL (n = 83) were used to identify ETP-ALL and investigate GATA3low and GATA3high expressing T-ALL patients. In addition, the ETP-ALL cell line PER-117 was investigated for cytotoxicity, apoptosis, GATA3 mRNA expression, DNA methylation, and global gene expression before and after treatment with decitabine. RESULTS: In our cohort of 70 ETP-ALL patients, 33 % (23/70) lacked GATA3 expression and were thus defined as GATA3low. DNA methylation analysis revealed a high degree of GATA3 CpG island methylation in GATA3low compared with GATA3high ETP-ALL patients (mean 46 vs. 21 %, p < 0.0001). Genome-wide expression profiling of GATA3low ETP-ALL exhibited enrichment of myeloid/lymphoid progenitor (MLP) and granulocyte/monocyte progenitor (GMP) genes, while T cell-specific signatures were downregulated compared to GATA3high ETP-ALL. Among others, FLT3 expression was upregulated and mutational analyses demonstrated a high rate (79 %) of FLT3 mutations. Hypomethylating agents induced reversal of GATA3 silencing, and gene expression profiling revealed downregulation of hematopoietic stem cell genes and upregulation of T cell differentiation. CONCLUSIONS: We propose GATA3low ETP-ALL as a novel stem cell-like leukemia with implications for the use of myeloid-derived therapies.

Diagnosis of invasive fungal infections in haematological patients by combined use of galactomannan, 1,3-ß-D-glucan, Aspergillus PCR, multifungal DNA-microarray, and Aspergillus azole resistance PCRs in blood and bronchoalveolar lavage samples: results of a prospective multicentre study.

High mortality rates of invasive fungal disease (IFD), especially invasive aspergillosis (IA), in immunocompromised haematological patients and current diagnostic limitations require improvement of detection of fungal pathogens by defining the optimal use of biomarkers and clinical samples. Concurrent bronchoalveolar lavage (BAL) and peripheral blood samples of 99 haematological patients with suspected IFD were investigated within a multicentre prospective study. Diagnostic performance of a galactomannan (GM) enzyme immune assay (EIA), a 1,3-ß-D-glucan assay (BDG), an Aspergillus PCR, and a multifungal DNA-microarray (Chip) alone or in combination were calculated. IFD were classified as proven (n=3), probable (n=34), possible (n=33), and no IFD (n=29) according to EORTC/MSG criteria. GM, PCR, and Chip showed superior diagnostic performance in BAL than in blood, whereas specificity of BDG in BAL was poor (48% (14/29)). The combination of GM (BAL) with BDG (blood) showed sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and DOR (diagnostic odds ratio) of 92% (34/37), 93% (27/29), 94%, 90%, and 153.0, respectively. Combining GM (BAL) with PCR (BAL) showed convincing diagnostic potential for diagnosing IA with sensitivity, specificity, PPV, NPV, and DOR of 85% (17/20), 97% (28/29), 94%, 90%, and 158.7. Addition of the DNA-microarray resulted in further detection of two mucormycetes infections. In 1 out of 15 Aspergillus DNA-positive samples a triazole resistance-mediating Cyp51A mutation was found. Combination of biomarkers is superior to their sole use in diagnosing IFD, particularly IA. Integrating blood and BAL samples into a diagnostic algorithm is an advantageous approach.

Safety assessment of jumps in ski racing.

The influence of important parameters on the flight trajectory for jumps in downhill World Cup races was investigated. To quantify the impact injury risk at landing, the parameter equivalent landing height (ELH) was introduced, which considered a variable slope inclination during the landing movement. Altogether, 145 runs at four different jumps in World Cup races and trainings were recorded and analyzed. A simulation model was developed to predict the flight phase of the skier. Drag and lift areas were selected by parameter identification to fit the simulation trajectory to the two-dimensional data from the video analysis. The maximum values of the ELH which can be absorbed with muscle force was taken from the study of Minetti et al. for elite female and male ski racers. A sensitivity analysis based on the four jumps showed that ELH is mainly influenced by takeoff angle, takeoff speed, and the steepness of the landing surface. With the help of the developed simulation software, it should be possible to predict the ELH for jumps in advance. In case of an excessive ELH, improvements can be made by changing the takeoff inclination or the approach speed.

Expression of transketolase-like gene 1 (TKTL1) depends on disease phase in patients with chronic myeloid leukaemia (CML).

PURPOSE: Overexpression of transketolase-like gene 1 (TKTL1) on RNA and protein level has been linked to tumour progression, metastasis and unfavourable patient outcome in many solid tumours. Chronic myeloid leukaemia (CML) cells show metabolic characteristics resembling deviations observed in TKTL1 overexpressing solid tumour cells. We therefore sought to evaluate TKTL1 gene expression in different phases of CML. METHODS: A total of 120 peripheral blood samples from 69 patients in various phases of CML and 21 healthy individuals were investigated. TKTL1 expression levels were determined by real-time quantitative polymerase chain reaction using LightCycler technology and normalised against beta-glucuronidase expression. RESULTS: A significantly lower TKTL1 expression was found in chronic phase (CP) CML patients compared to healthy controls. Lowest expression levels were observed in patients during blast crisis (BC). Baseline TKTL1 expression in CP patients did not have value in prognostication of subsequent favourable or dismal outcome. Further, more mature granulocytes showed significantly higher TKTL1 expression compared to immature CD34+ and CD34-/CD33+ cells both in healthy controls and in CML patients. CONCLUSION: TKTL1 expression levels appear to decline in the course of CML with lowest levels during BC. A potential reason is a shift of TKTL1-high-expressing mature granulocytes towards TKTL1-low-expressing immature cells and blasts.

Modeling the ski-snow contact in skiing turns using a hypoplastic vs an elastic force-penetration relation.

A ski-snow interaction model is presented. The force between ski and snow is decomposed into a penetration force normal to the snow surface, a shear force parallel to it, and friction. The purpose of this study was to investigate the benefits of a hypoplastic vs an elastic contact for penetration in the simulation of skiing turns. To reduce the number of influencing factors, a sledge equipped with skis was considered. A forward dynamic simulation model for the sledge was implemented. For the evaluation of both contact models, the deviation between simulated trajectories and experimental track data was computed for turns of 67 and 42 m. Maximum deviations for these turns were 0.44 and 0.14 m for the hypoplastic contact, and 0.6 and 7.5 m for the elastic contact, respectively. In the hypoplastic contact, the penetration depth of the ski's afterbody maintained nearly the same value as the part under maximum load, whereas it decreased in the elastic contact. Because the shear force is proportional to the penetration depth, the hypoplastic contact resulted in a higher shearing resistance. By replacing the sledge with a skier model, one may investigate more complex skier actions, skiing performance, or accident-prone skiing maneuvers.

Calculation of the contact pressure between ski and snow during a carved turn in Alpine skiing.

The macroscopic contact area between ski and snow and the contact pressure are crucial influencing factors for carved turns in Alpine skiing. In the present paper, a simulation model is developed to quantify these factors. The ski is modelled as an Euler-Bernoulli beam with variable cross section, camber, bending and torsional stiffness using measured data from skis. The reaction forces of the snow are decomposed in penetration and shear forces. For the penetration forces a hypoplastic constitutive law is applied incorporating elastic and plastic deformation of the snow at the contact area. For the shear forces metal cutting theory is used. Ski deformation, contact area and contact pressure are computed based on quasi-static equilibrium between forces exerted by the skier and snow reaction forces. Parameter studies are performed to investigate the influence of edging and distributing the load between the inner and outer ski. Higher edging angles as well as loading both skis affected the contact pressure positively by increasing the resistance against shearing. The results of our study agree well with measurement data taken from literature. Based on the results, the importance of actions of the skier during carved turns is concluded.

[Effect of ski tapering on turning radius and stress]. / Einfluss der Skitaillierung auf Schwungradius und Belastung.

The first part of this paper deals with the influence of the side cut on the turn radius, which was examined by measuring the turn radius of a self-running sledge-like construction and by comparing it to Howe's prediction. The turn radius at the beginning of the turn has proved to be between 65 and 85% of the theoretically expected result. In the second part a carvers turn radius was determined and the reaction force acting on the skier was calculated. The result shows a strong reduction of the turn radius along the path which increases the load on the skier. The effect of side cut and velocity on the load was examined. Using carver skis even small changes in velocity resulted in considerable load changes.