Prognostic factors in allo-SCT of elderly patients with AML

The prognosis of elderly patients with AML after chemotherapy is poor. Allo-SCT is feasible in these patients, but data on prognostic factors and outcome are limited. We analyzed all 102 AML patients ≥55 years, who underwent allo-SCT at our institution from 1997 to 2008. OS and relapse-free survival (RFS) rates at 3 years are 39 and 37%, respectively. Multivariate analysis for OS revealed age ≥60 years and active (refractory or untreated before allo-SCT) or advanced (>CR1) disease as adverse prognostic factors. Patients transplanted in CR1 had a 3-year OS of 67 vs 27% for patients with active/advanced disease. Multivariate analysis for RFS revealed active/advanced disease as the only adverse factor. Patients transplanted in CR1 had a 3-year RFS of 70 vs 22% for patients with active/advanced disease. In all, 17% of patients suffered from acute GVHD ≥grade II. The risk for severe acute GVHD was increased after allo-SCT from mismatched donors. Nonrelapse mortality (NRM) was 23% at 1 year. The only risk factor for NRM was active/advanced disease. In conclusion, allo-SCT from related or unrelated donors yields very good results in elderly AML patients transplanted in CR1. Disease status at transplantation is the most important prognostic factor for transplantation success.

IDH1 mutations in patients with myelodysplastic syndromes are associated with an unfavorable prognosis

BACKGROUND

Myelodysplastic syndromes are a heterogeneous group of hematopoietic stem cell disorders with a high propensity to transform into acute myeloid leukemia. Heterozygous missense mutations in IDH1 at position R132 and in IDH2 at positions R140 and R172 have recently been reported in acute myeloid leukemia. However, little is known about the incidence and prognostic impact of IDH1 and IDH2 mutations in myelodysplastic syndromes.

DESIGN AND METHODS

We examined 193 patients with myelodysplastic syndromes and 53 patients with acute myeloid leukemia arising from myelodysplastic syndromes for mutations in IDH1 (R132), IDH2 (R172 and R140), and NPM1 by direct sequencing.

RESULTS

We found that mutations in IDH1 occurred with a frequency of 3.6% in myelodysplastic syndromes (7 mutations in 193 patients) and 7.5% in acute myeloid leukemia following myelodysplastic syndromes (4 mutations in 53 patients). Three mutations in codon R140 of IDH2 and one mutation in codon R172 were found in patients with acute myeloid leukemia following myelodysplastic syndromes (7.5%). No IDH2 R140 or R172 mutations were identified in patients with myelodysplastic syndromes. The presence of IDH1 mutations was associated with a shorter overall survival (HR 3.20; 95% CI 1.47-6.99) and a higher rate of transformation into acute myeloid leukemia (67% versus 28%, P=0.04). In multivariate analysis when considering karyotype, transfusion dependence and International Prognostic Scoring System score, IDH1 mutations remained an independent prognostic marker in myelodysplastic syndromes (HR 3.57; 95% CI 1.59-8.02; P=0.002).

CONCLUSIONS

These results suggest that IDH1 mutations are recurrent molecular aberrations in patients with myelodysplastic syndromes, and may become useful as a poor risk marker in these patients. These findings await validation in prospective trials.

Parameter identification, experimental design and model falsification for biological network models using semidefinite programming

One of the most challenging tasks in systems biology is parameter identification from experimental data. In particular, if the available data are noisy, the resulting parameter uncertainty can be huge and should be quantified. In this work, a set-based approach for parameter identification in discrete time models of biochemical reaction networks from time series data is developed. The basic idea is to determine an outer approximation to the set of parameters for which trajectories are consistent with the available data. In order to approximate the set of consistent parameters (SCP) a feasibility problem is derived. This feasibility problem is used to verify that complete parameter sets cannot contain consistent parameters. This method is very appealing because instead of checking a finite number of distinct points, complete sets are analysed. With this approach, model falsification simply corresponds to showing that the SCP is empty. Besides parameter identification, a novel set-based method for experimental design is presented. This method yields reliable predictions on the information content of future measurements also for the case of very limited a priori knowledge and uncertain inputs. The properties of the method are presented using a discrete time model of the MAP kinase cascade.

Impact of IDH1 R132 mutations and an IDH1 single nucleotide polymorphism in cytogenetically normal acute myeloid leukemia: SNP rs11554137 is an adverse prognostic factor

PURPOSE

We assessed the prognostic impact of IDH1 R132 mutations and a known single nucleotide polymorphism (SNP) located in the same exon of the IDH1 gene in patients with cytogenetically normal acute myeloid leukemia (CN-AML) in the context of other prognostic markers.

PATIENTS AND METHODS

IDH1 exon four was directly sequenced in 275 CN-AML patients from two subsequent AML multicenter treatment trials and 120 healthy volunteers. Moreover, mutations in NPM1, FLT3, CEBPA, and WT1 were analyzed, and mRNA expression of IDH1 was quantified.

RESULTS

IDH1 R132 mutations were found in 10.9% of CN-AML patients. IDH1 SNP rs11554137 was found in 12% of CN-AML patients and 11.7% of healthy volunteers. IDH1 R132 mutations had no impact on prognosis. In contrast, IDH1 SNP rs11554137 was an adverse prognostic factor for overall survival in univariate and multivariate analysis. Other significant factors were age, NPM1/FLT3 mutational status, WT1 SNP rs16754, and platelet count. The impact of IDH1 SNP rs11554137 was most pronounced in the NPM1/FLT3 high-risk patients (either NPM1 wild-type or FLT3-internal tandem duplication positive). Patients with IDH1 SNP rs11554137 had a higher expression of IDH1 mRNA than patients with two wild-type alleles.

CONCLUSION

IDH1 SNP rs11554137 but not IDH1 R132 mutations are associated with an inferior outcome in CN-AML.

Lesional magnetization transfer ratio: a feasible outcome for remyelinating treatment trials in multiple sclerosis

Magnetization transfer ratio (MTR) is a sensitive parameter to quantify the integrity of myelinated white matter in patients with multiple sclerosis. Lesional MTR decreases in the acute phase due to demyelination, and subsequently shows recovery depending on the degree of remyelination in the absence of axonal loss. Recovery of average lesion MTR therefore might prove a viable outcome measure to assess the effect of remyelinating agents. Our objective was to determine the required sample size for phase II multicentre clinical trials using the recovery of average lesion MTR as primary outcome measure. With 7-monthly MRI scans, the MTR evolution of 349 new enhancing lesions before and after enhancement was assessed in 32 MS patients from 5 centres. Multilevel models were fitted to the data yielding estimates for the variance components, which were applied in power calculations. Sample sizes were determined for placebo-controlled, multicentre trials using lesional MTR recovery post-enhancement as primary outcome measure. Average lesion MTR decreased slightly in the build-up to enhancement, decreased dramatically during enhancement and showed recovery in the period after cessation. The power calculations showed that for a power of 80%, approximately 136 patients per trial (mean number of 6 lesions per patient) are required to detect a 30% increase in lesional MTR post-enhancement compared with placebo, whereas 48 subjects are required to detect a 50% increase in lesional MTR compared with placebo. Recovery of lesion MTR is a feasible outcome measure for future multicentre clinical trials measuring the effect of remyelinating agents.

Parameter identification, experimental design and model falsification for biological network models using semidefinite programming

One of the most challenging tasks in systems biology is parameter identification from experimental data. In particular, if the available data are noisy, the resulting parameter uncertainty can be huge and should be quantified. In this work, a set-based approach for parameter identification in discrete time models of biochemical reaction networks from time series data is developed. The basic idea is to determine an outer approximation to the set of parameters for which trajectories are consistent with the available data. In order to approximate the set of consistent parameters (SCP) a feasibility problem is derived. This feasibility problem is used to verify that complete parameter sets cannot contain consistent parameters. This method is very appealing because instead of checking a finite number of distinct points, complete sets are analysed. With this approach, model falsification simply corresponds to showing that the SCP is empty. Besides parameter identification, a novel set-based method for experimental design is presented. This method yields reliable predictions on the information content of future measurements also for the case of very limited a priori knowledge and uncertain inputs. The properties of the method are presented using a discrete time model of the MAP kinase cascade.

{N',N''-Bis[2,6-bis-(1-methyl-ethyl)phen-yl]-N,N-dimethyl-guanidinato-κN',N''}dibromido-borane

In the mol-ecular structure of the title compound, C(27)H(40)N(3)BBr(2), the B atom is connected to two bromide substituents and a guanidinate scaffold, forming a four-membered ring. An aryl group is connected to each N atom in the ring that contains two isopropyl groups in positions 2 and 6.

Dicyclohexyl(2′,4′,6′-triisopropylbiphenyl-2-yl)phosphine–dichlorophenylborane

In the crystal structure of the title compound, C₃₉H₅₄BCl₂P, the phospho­rus atom is coordinated by a dichloro­phenyl­borane unit. The substituted biphenyl group and the two cyclo­hexyl groups at the phospho­rus atom are arranged in such a way to avoid steric crowding in the mol­ecule as far as possible.

Structure solution with PATSEE

Patterson search is a powerful tool for solving difficult crystal structures since it actively uses chemical information. Our program PATSEE, which attempts to combine the merits of Patterson and direct methods in order to locate a fragment with known geometry in the unit cell, has solved a large number of crystal structures during the last decade and proved to be reliable and widely applicable. We have tested PATSEE successfully on 20 structures of different size and complexity contained in a test data bank using fragments either taken from related crystal structures or calculated by force-field methods. Even structures with several torsional degrees of freedom (like those of oligopeptides) could be solved convincingly. As a result, general experiences – such as requirements for the minimum size and the accuracy of a search fragment, the reliability of the various figures of merit, the chances to locate single atoms and to tackle larger structures – were gained, which should help in finding an optimum strategy for the solution of problem structures with PATSEE.

GARP: a key receptor controlling FOXP3 in human regulatory T cells

Recent evidence suggests that regulatory pathways might control sustained high levels of FOXP3 in regulatory CD4(+)CD25(hi) T (T(reg)) cells. Based on transcriptional profiling of ex vivo activated T(reg) and helper CD4(+)CD25(-) T (T(h)) cells we have identified GARP (glycoprotein-A repetitions predominant), LGALS3 (lectin, galactoside-binding, soluble, 3) and LGMN (legumain) as novel genes implicated in human T(reg) cell function, which are induced upon T-cell receptor stimulation. Retroviral overexpression of GARP in antigen-specific T(h) cells leads to an efficient and stable re-programming of an effector T cell towards a regulatory T cell, which involves up-regulation of FOXP3, LGALS3, LGMN and other T(reg)-associated markers. In contrast, overexpression of LGALS3 and LGMN enhance FOXP3 and GARP expression, but only partially induced a regulatory phenotype. Lentiviral down-regulation of GARP in T(reg) cells significantly impaired the suppressor function and was associated with down-regulation of FOXP3. Moreover, down-regulation of FOXP3 resulted in similar phenotypic changes and down-regulation of GARP. This provides compelling evidence for a GARP-FOXP3 positive feedback loop and provides a rational molecular basis for the known difference between natural and transforming growth factor-beta induced T(reg) cells as we show here that the latter do not up-regulate GARP. In summary, we have identified GARP as a key receptor controlling FOXP3 in T(reg) cells following T-cell activation in a positive feedback loop assisted by LGALS3 and LGMN, which represents a promising new system for the therapeutic manipulation of T cells in human disease.

[Quality of life following extratemporal epilepsy surgery]

Extratemporal epileptic foci are increasingly treated successfully with surgery. This study assesses the effect of extratemporal epilepsy surgery on the subjective handicaps of epilepsy patients. Twenty-one adults with pharmacoresistant focal epilepsy undergoing extratemporal surgical interventions were analyzed compared to an age-, gender-, and IQ-matched patient group with temporal lobe epilepsy. A questionnaire on subjective handicaps was given prior to surgery and after 1 year of follow-up. There were significant postoperative improvements in the domains of work and activities, self perception, and judgement of changes in handicap. These changes were similar to those in patients undergoing temporal lobe surgery and not restricted to those achieving complete seizure remission. Epilepsy surgery thus improves not only seizure control but also quality of life in patients with extratemporal focus localization.