Diagnostic utility of the molecular assay GenoType MTBC (HAIN Lifesciences, Germany) for identification of tuberculous mycobacteria

Wstęp: Nowy kompleksowy system GenoType firmy HAIN Lifescience (Niemcy) stwarza szerokie możliwości w diagnostyce gruźlicy i innych zakażeń prątkowych na poziomie molekularnym. Dzięki wprowadzeniu 5 wzajemnie uzupełniających się testów, system ten pozwala na wykrycie i typowanie mykobakterii oraz określenie lekowrażliwości na rifampicynę i izoniazyd na różnych etapach postępowania diagnostycznego, od badania materiałów bezpośrednich do wyizolowanych szczepów. Zaletą systemu jest dowolność w wyborze stosowanych testów (bez konieczności wykonywania wszystkich), w zależności od potrzeb i aktualnie stosowanych innych metod wykrywania prątków. System posiada certyfikat Unii Europejskiej do stosowania w rutynowej diagnostyce. Dotychczas żaden z testów systemu GenoType nie był stosowany w Polsce. Celem prezentowanej pracy była ocena precyzji typowania testem GenoType MTBC izolatów klinicznych zidentyfikowanych uprzednio jako M. tuberculosis complex metodą wysokociśnieniowej chromatografii cieczowej w ramach rutynowego postępowania diagnostycznego. Materiał i metody: Badanie miało charakter retrospektywny. Testem GenoType MTBC zbadano 161 izolatów klinicznych M. tuberculosis complex. Szczepy pochodziły od chorych na gruźlicę hospitalizowanych w Centralnym Szpitalu Klinicznym Warszawskiego Uniwersytetu Medycznego w latach 1999-2007. Wyniki: Typowanie testem GenoType MTBC okazało się w 100% zgodne z typowaniem metodą analizy kwasów mykolowych. Test GenoType MTBC wykazał ponadto, że wszystkie izolaty miały wzór hybrydyzacji charakterystyczny dla M. tuberculosis/M. canettii. Wnioski: 1. Test GenoType MTBC (HAIN Lifescience, Niemcy) prawidłowo rozpoznaje kliniczne szczepy M. tuberculosis complex i może w tym zakresie zastąpić wysokociśnieniową chromatografię cieczową w rutynowej diagnostyce gruźlicy. 2. W świetle pozytywnej oceny testu GenoType MTBC celowe wydaje się rozpatrzenie możliwości stosowania pozostałych testów systemu GenoType (HAIN Lifescience, Niemcy) w diagnostyce zakażeń prątkowych.Introduction: The GenoType system (HAIN Lifescience, Germany) offers new perspectives of detecting the tuberculous and non-tuberculous mycobacteria at the molecular level. The system compromises five independent tests that could be performed either on direct specimens or isolated strains, to identify the strains and test the resistance against rifampin and isoniazid. Up to now, non GenoType test was applied in Poland. The aim of the study was an evaluation the accuracy of GenoType MTBC test in speciation of the clinical isolates, previously classified as M. tuberculosis complex by HPLC analyze of mycolic acids. Material and methods: 161 clinical isolates, derived from the TB patients hospitalized in the Warsaw Medical University Hospital between 1999 and 2007 were assayed. Results: On the basis of the hybridization patterns, all 161 studied strains were identified as M. tuberculosis/M. canettii. Conclusions: 1. The GenoType MTBC test (HAIN Lifescience, Germany) precisely recognizes M. tuberculosis complex. The 100% accordance in speciation of M. tuberculosis by the GenoType MTBC test as compared to HPLC method was demonstrated. The GenoType MTBC test can replace HPLC in detection of tuberculous mycobacteria in clinical isolates. 2. As the GenoType MTBC test performs well, the other tests of GenoType system may be considered to be verified in diagnostic procedure of mycobacterial infection

Requirements for tracking radar for falling spheres

Error analysis on radar tracking of falling sphere

Vanishing resonance and representations of Lie algebras

We explore a relationship between the classical representation theory of a complex, semisimple Lie algebra \g and the resonance varieties R(V,K)\subset V^* attached to irreducible \g-modules V and submodules K\subset V\wedge V. In the process, we give a precise roots-and-weights criterion insuring the vanishing of these varieties, or, equivalently, the finiteness of certain modules W(V,K) over the symmetric algebra on V. In the case when \g=sl_2(C), our approach sheds new light on the modules studied by Weyman and Eisenbud in the context of Green's conjecture on free resolutions of canonical curves. In the case when \g=sl_n(C) or sp_{2g}(C), our approach yields a unified proof of two vanishing results for the resonance varieties of the (outer) Torelli groups of surface groups, results which arose in recent work by Dimca, Hain, and the authors on homological finiteness in the Johnson filtration of mapping class groups and automorphism groups of free groups.Comment: 17 pages; Corollary 1.3 stated in stronger form, with a shorter proo

Equivalences between spin models induced by defects

The spectrum of integrable spin chains are shown to be independent of the ordering of their spins. As an application we introduce defects (local spin inhomogeneities in homogenous chains) in two-boundary spin systems and, by changing their locations, we show the spectral equivalence of different boundary conditions. In particular we relate certain nondiagonal boundary conditions to diagonal ones.Comment: 14 pages, 16 figures, LaTeX, Extended versio

Kinetically driven helix formation during the homopolymer collapse process

Using Langevin simulations, we find that simple 'generic' bead-and-spring homopolymer chains in a sufficiently bad solvent spontaneously develop helical order during the process of collapsing from an initially stretched conformation. The helix formation is initiated by the unstable modes of the straight chain, which drive the system towards a long-lived metastable transient state. The effect is most pronounced if hydrodynamic interactions are screened.Comment: 4 pages, 4 figure

Matrix product state comparison of the numerical renormalization group and the variational formulation of the density matrix renormalization group

Wilson's numerical renormalization group (NRG) method for solving quantum impurity models yields a set of energy eigenstates that have the form of matrix product states (MPS). White's density matrix renormalization group (DMRG) for treating quantum lattice problems can likewise be reformulated in terms of MPS. Thus, the latter constitute a common algebraic structure for both approaches. We exploit this fact to compare the NRG approach for the single-impurity Anderson model to a variational matrix product state approach (VMPS), equivalent to single-site DMRG. For the latter, we use an ``unfolded'' Wilson chain, which brings about a significant reduction in numerical costs compared to those of NRG. We show that all NRG eigenstates (kept and discarded) can be reproduced using VMPS, and compare the difference in truncation criteria, sharp vs. smooth in energy space, of the two approaches. Finally, we demonstrate that NRG results can be improved upon systematically by performing a variational optimization in the space of variational matrix product states, using the states produced by NRG as input.Comment: 19 pages, 14 figure

Koszul duality and equivariant cohomology for tori

Let T be a torus. We show that Koszul duality can be used to compute the equivariant cohomology of topological T-spaces as well as the cohomology of pull backs of the universal T-bundle. The new features are that no further assumptions about the spaces are made and that the coefficient ring may be arbitrary. This gives in particular a Cartan-type model for the equivariant cohomology of a T-space with arbitrary coefficients. Our method works for intersection homology as well.Comment: 37 pages; to appear in Int. Math. Res. No