Biomedical subjects

Tanja Boes

Publications and source records attributed to Tanja Boes.

5 recordsLinked to original sources

PubMed2006

Treatment of severe acute respiratory distress syndrome: role of extracorporeal gas exchange.

OBJECTIVE: To evaluate the effect of extracorporeal gas exchange (ECMO) on mortality of patients referred with severe acute respiratory distress syndrome (ARDS). DESIGN AND SETTING: Prospective observational study in a university hospital ICU. PATIENTS: 150 patients with severe ARDS. INTERVENTIONS: Multimodal treatment with and without ECMO. MEASUREMENTS AND MAIN RESULTS: We treated 118 patients (78.7%) conservatively and 32 patients with ECMO. Patients in the ECMO group presented with significantly more severe disease (lung injury score 3.8+/-0.3 vs. 3.3+/-0.4; SOFA score 52+/-14 vs. 43+/-12; and SAPS score 14+/-3.3 vs. 10+/-3.5). Mortality in ECMO-treated patients tended to be higher than that with conservative treatment (46.9% vs. 28.8%, p=0.059). Multivariate logistic regression analyses with backward selection excluded ECMO as predictor of mortality (p=0.79). Independent predictors of mortality were age (odds ratio 1.044, 95% confidence interval 1.014-1.075, p=0.004), mean pulmonary artery pressure (1.082, 1.026-1.141, p=0.036), sequential organ failure assessment score (1.148, 1.018-1.294, p=0.024), and days of mechanical ventilation prior to referral (1.064, 1.008-1.123, p=0.025). CONCLUSION: ECMO treatment does not predict mortality in patients with most severe ARDS.

Adult↗

PubMed2006

Prevalence of pulmonary hypertension associated with severe acute respiratory distress syndrome: predictive value of computed tomography.

OBJECTIVE: To evaluate the prevalence of pulmonary hypertension associated with severe acute respiratory distress syndrome (ARDS) and to asses the value of pulmonary artery trunk diameter (PAT) to predict pulmonary hypertension. DESIGN: Prospective study SETTING: University teaching hospital and ARDS referral center. PATIENTS: 103 patients with ARDS, who received both right heart catheterization and chest computed tomography. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: 95 patients (92.2%) with ARDS had pulmonary artery hypertension, 16 of them (16.8%) mild, 72 (75.8%) moderate, and 7 (7.4%) severe, as assessed by right heart catheterization. Of the patients with moderate and severe pulmonary hypertension, 43 had a pulmonary artery trunk diameter >or=29 mm yielding a sensitivity of 0.54 and a specificity of 0.63. Pulmonary artery trunk diameter correlated significantly but weakly with mean pulmonary artery pressure (r=0.34, p=0.0004). The positive predictive value was 0.83, and the negative predictive value was 0.28. The diagnosis of pulmonary hypertension by PAT diameter measurements was incorrect in 43.7% of patients with ARDS. CONCLUSIONS: Pulmonary artery hypertension has a high prevalence in patients with severe ARDS. Measurement of PAT diameter on admission CT scan is an unreliable tool for identification of ARDS patients with pulmonary hypertension.

Comorbidity↗

PubMed2006

Gene expression profiles in murine hematopoietic stem cells revisited: analysis of cDNA libraries reveals high levels of translational and metabolic activities.

Gene expression studies from hematopoietic stem cell (HSC) populations purified to variable degrees have defined a set of stemness genes. Unexpectedly, results also hinted toward a HSC chromatin poised in a wide-open state. With the aim of providing a robust tool for further studies into the molecular biology of HSCs, the studies herein describe the construction and comparative molecular analysis of lambda-phage cDNA libraries from highly purified HSCs that retained their long-term repopulating activities (long-term HSCs [LT-HSCs]) and from short-term repopulating HSCs that were largely depleted of these activities. Microarray analysis of the libraries confirmed the previous results but also revealed an unforeseen preferential expression of translation- and metabolism-associated genes in the LT-HSCs. Therefore, these data indicate that HSCs are quiescent only in regard of proliferative activities but are in a state of readiness to provide the metabolic and translational activities required after induction of proliferation and exit from the HSC pool.

Animals↗

PubMed2005

Two-part permutation tests for DNA methylation and microarray data.

BACKGROUND: One important application of microarray experiments is to identify differentially expressed genes. Often, small and negative expression levels were clipped-off to be equal to an arbitrarily chosen cutoff value before a statistical test is carried out. Then, there are two types of data: truncated values and original observations. The truncated values are not just another point on the continuum of possible values and, therefore, it is appropriate to combine two statistical tests in a two-part model rather than using standard statistical methods. A similar situation occurs when DNA methylation data are investigated. In that case, there are null values (undetectable methylation) and observed positive values. For these data, we propose a two-part permutation test. RESULTS: The proposed permutation test leads to smaller p-values in comparison to the original two-part test. We found this for both DNA methylation data and microarray data. With a simulation study we confirmed this result and could show that the two-part permutation test is, on average, more powerful. The new test also reduces, without any loss of power, to a standard test when there are no null or truncated values. CONCLUSION: The two-part permutation test can be used in routine analyses since it reduces to a standard test when there are positive values only. Further advantages of the new test are that it opens the possibility to use other test statistics to construct the two-part test and that it avoids the use of any asymptotic distribution. The latter advantage is particularly important for the analysis of microarrays since sample sizes are usually small.

Algorithms↗

PubMed2003

Combining DNA expression with positional information to detect functional silencing of chromosomal regions.

MOTIVATION: Loss of chromosomal material is often observed in cancer cells. In this situation the expression of genes is related to their position on the genome. Epigenetic phenomena may also silence several genes in the same region of a chromosome. While cytogenetic or other molecular genetic methods spot changes of DNA copy number, they cannot detect other causes of silencing. RESULTS: We propose a method that utilizes the link from expression information gained from high-density DNA microarrays to the gene locus according to current databases. Statistical methods adequate to spot conspicuous runs of non-expressed genes are introduced and compared to one another by merit of their power and robustness against false positives. AVAILABILITY: Code for the formulae can be obtained (R code) via http://www.panix.com/~derwisch/hannes/longrun

Chromosome Mapping↗