Reconstructing in-depth activity for chaotic 3D spatiotemporal excitable media models based on surface data

Motivated by potential applications in cardiac research, we consider the task of reconstructing the dynamics within a spatiotemporal chaotic 3D excitable medium from partial observations at the surface. Three artificial neural network methods (a spatiotemporal convolutional long-short-term-memory, an autoencoder, and a diffusion model based on the U-Net architecture) are trained to predict the dynamics in deeper layers of a cube from observational data at the surface using data generated by the Barkley model on a 3D domain. The results show that despite the high-dimensional chaotic dynamics of this system, such cross-prediction is possible, but non-trivial and as expected, its quality decreases with increasing prediction depth.

Convolutional autoencoder and conditional random fields hybrid for predicting spatial-temporal chaos

We present an approach for data-driven prediction of high-dimensional chaotic time series generated by spatially-extended systems. The algorithm employs a convolutional autoencoder for dimension reduction and feature extraction combined with a probabilistic prediction scheme operating in the feature space, which consists of a conditional random field. The future evolution of the spatially-extended system is predicted using a feedback loop and iterated predictions. The excellent performance of this method is illustrated and evaluated using Lorenz-96 systems and Kuramoto-Sivashinsky equations of different size generating time series of different dimensionality and complexity.

Die neuropathische Drüsenmagendilatation der Psittaziden und das aviäre Bornavirus als potenzielle Ursache

Gegenstand: Die neuropathische Drüsenmagendilatation der Psittaziden (PDD) ist eine bedeutende Erkrankung von Papageien, die stets letal endet. Sie tritt bei zahlreichen Papageienspezies auf und bedroht ganze Zuchtbestände, kommt bei anderen Vogelfamilien dagegen sehr selten vor. Die Ursache dieser Erkrankung war bislang unklar, obwohl schon lange eine Virusätiologie vermutet wurde. Kürzlich gelang der Nachweis eines neuen Virus (aviäres Bornavirus [ABV]) aus an PDD erkrankten Papageien, das seitdem als wahrscheinlichste Ursache gilt. Obwohl auch klinisch gesunde Papageien eine ABV-Infektion aufweisen können, zeigen verschiedene Studien einen Zusammenhang zwischen der Virusinfektion und der klinischen Erkrankung der PDD auf. Neben dem direkten Virusnachweis eignen sich auch serologische Methoden zum Infektionsnachweis. Schlussfolgerungen: Das aviäre Bornavirus ist zurzeit der wahrscheinlichste Kandidat als Erreger der PDD. Zuchtbestände und Neuzugänge sollten daher molekularbiologisch und serologisch auf eine Infektion mit ABV überprüft werden. Der diagnostische Wert des ABV-Infektionsnachweises zur Absicherung der klinischen Diagnose PDD muss in weiteren Studien genauer abgeklärt werden.

MAP3K11 is a tumor suppressor targeted by the oncomiR miR-125b in early B cells

MicroRNAs (miRNAs) are a class of small, non-coding RNAs that posttranscriptionally regulate gene expression and thereby control most, if not all, biological processes. Aberrant miRNA expression has been linked to a variety of human diseases including cancer, but the underlying molecular mechanism often remains unclear. Here we have screened a miRNA expression library in a growth factor-dependent mouse pre-B-cell system to identify miRNAs with oncogenic activity. We show that miR-125b is sufficient to render pre-B cells growth factor independent and demonstrate that continuous expression of miR-125b is necessary to keep these cells in a transformed state. Mechanistically, we find that the expression of miR-125b protects against apoptosis induced by growth factor withdrawal, and that it blocks the differentiation of pre-B to immature B cells. In consequence, miR-125b-transformed cells maintain expression of their pre-B-cell receptor that provides signals for continuous proliferation and survival even in the absence of growth factor. Employing microarray analysis, we identified numerous targets of miR-125b, but only reconstitution of MAP3K11, a critical regulator of mitogen- and stress-activated kinase signaling, interferes with the cellular fitness of the transformed cells. Together, this indicates that MAP3K11 might function as an important tumor suppressor neutralized by oncomiR-125b in B-cell leukemia.

Conditional knockdown of BCL2A1 reveals rate-limiting roles in BCR-dependent B-cell survival

Bcl2 family proteins control mitochondrial apoptosis and its members exert critical cell type and differentiation stage-specific functions, acting as barriers against autoimmunity or transformation. Anti-apoptotic Bcl2a1/Bfl1/A1 is frequently deregulated in different types of blood cancers in humans but its physiological role is poorly understood as quadruplication of the Bcl2a1 gene locus in mice hampers conventional gene targeting strategies. Transgenic overexpression of A1, deletion of the A1-a paralogue or constitutive knockdown in the hematopoietic compartment of mice by RNAi suggested rate-limiting roles in lymphocyte development, granulopoiesis and mast cell activation. Here we report on the consequences of conditional knockdown of A1 protein expression using a reverse transactivator (rtTA)-driven approach that highlights a critical role for this Bcl2 family member in the maintenance of mature B-cell homeostasis. Furthermore, we define the A1/Bim (Bcl-2 interacting mediator of cell death) axis as a target of key kinases mediating B-cell receptor (BCR)-dependent survival signals, such as, spleen tyrosine kinase (Syk) and Brutons tyrosine kinase (Btk). As such, A1 represents a putative target for the treatment of B-cell-related pathologies depending on hyperactivation of BCR-emanating survival signals and loss of A1 expression accounts, in part, for the pro-apoptotic effects of Syk- or Btk inhibitors that rely on the ‘BH3-only' protein Bim for cell killing.

Zur Existenz des Tris-2.2’-Dipyridyl-Vanadin (1)-Jodids [VIdip3] J ½ py

The results of spectroscopic and paramagnetic resonance investigations show that the previously prepared substance with the empirical composition [VIdip3] J · ½ py is most presumably a mixed crystal of two similar compounds of bivalent and zero-valent vanadium. The ion [VIdip3] +⃝ exists only in solution and gives no paramagnetic resonance signal, which is understood on account of a low-lying singlet ground state.

Investigations of cerebrospinal fluid in Borna disease virus seropositive psychiatric patients

Borna disease virus (BDV) appears to cause meningoencephalitis and schizophreniform psychosis in sporadic cases according to earlier cerebrospinal fluid (CSF) inoculation experiments (Rott et al, 1991). However, CSF parameters in BDV seropositive psychiatric patients proved nearly all normal; only the most sensitive CSF/serum index I-BDV for intrathecally produced BDV specific IgG was pathologic in 10.5-29.0% (according to different methodological limits) of patients. An increase in sensitivity was attempted to detect specific IgG in CSF in a part of the cases by concentration. Concentration procedure does not significantly increase methodological bias according to a statistical analysis of the results. Our findings support the hypothesis that BDV may cause or contribute to the pathogenesis of a diagnostically broad pattern of psychiatric syndromes. The occurence of a spectrum of diagnoses is expected from non-specificity of psychiatric symptoms in other infectious diseases of the brain as well as from results in experimental Borna disease (BD) in animals, when a majority of the animals showed rather unspecific symptomatology due to slight, preferentially limbic encephalitis. Slight deficiencies from an earlier BDV infection could explain continuing symptoms in a part of the cases. Recurrences years after infection are well known in experimental and natural BD in animals. It remains open, whether this mechanism could play a more prominent role in a form of "symptomatic" cyclothymia and "symptomatic" schizophrenia, although the results of CSF investigations are more clear in BDV seropositive patients with major psychoses.

Regulation of interferon-inducible proteins by doxorubicin via interferon γ-Janus tyrosine kinase-signal transducer and activator of transcription signaling in tumor cells

Activation of the immune system is a way for host tissue to defend itself against tumor growth. Hence, treatment strategies that are based on immunomodulation are on the rise. Conventional cytostatic drugs such as the anthracycline doxorubicin can also activate immune cell functions of macrophages and natural killer cells. In addition, cytotoxicity of doxorubicin can be enhanced by combining this drug with the cytokine interferon-γ (IFNγ). Although doxorubicin is one of the most applied cytostatics, the molecular mechanisms of its immunomodulation ability have not been investigated thoroughly. In microarray analyses of HeLa cells, a set of 19 genes related to interferon signaling was significantly over-represented among genes regulated by doxorubicin exposure, including signal transducer and activator of transcription (STAT) 1 and 2, interferon regulatory factor 9, N-myc and STAT interactor, and caspase 1. Regulation of these genes by doxorubicin was verified with real-time polymerase chain reaction and immunoblotting. An enhanced secretion of IFNγ was observed when HeLa cells were exposed to doxorubicin compared with untreated cells. IFNγ-neutralizing antibodies and inhibition of Janus tyrosine kinase (JAK)-STAT signaling [aurintricarboxylic acid (ATA), (E)-2-cyano-3-(3,4-dihydrophenyl)-N-(phenylmethyl)-2-propenamide (AG490), STAT1 small interfering RNA] significantly abolished doxorubicin-stimulated expression of interferon signaling-related genes. Furthermore, inhibition of JAK-STAT signaling significantly reduced doxorubicin-induced caspase 3 activation and desensitized HeLa cells to doxorubicin cytotoxicity. In conclusion, we demonstrate that doxorubicin induces interferon-responsive genes via IFNγ-JAK-STAT1 signaling and that this pathway is relevant for doxorubicin's cytotoxicity in HeLa cells. Immunomodulation is a promising strategy in anticancer treatment, so this novel mode of action of doxorubicin may help to further improve the use of this drug among different types of anticancer treatment strategies.

Dzyaloshinskii-Moriya interaction in transport through single-molecule transistors

The Dzyaloshinskii-Moriya interaction is shown to result in a canting of spins in a single-molecule transistor. We predict nonlinear transport signatures of this effect induced by spin-orbit coupling for the generic case of a molecular dimer. The conductance is calculated using a master equation and is found to exhibit a non-trivial dependence on the magnitude and direction of an external magnetic field. We show how three-terminal transport measurements allow for a determination of the coupling vector characterizing the Dzyaloshinskii-Moriya interaction. In particular, we show how its orientation, defining the intramolecular spin chirality, can be probed with ferromagnetic electrodes.

Borna disease in an adult alpaca stallion (Lama pacos)

Borna disease (BD) was diagnosed in a 2-year-old male alpaca with a history of chronic suppressed sexual desire and acute stretching convulsions. Microscopical examination of the central nervous system revealed non-purulent meningoencephalitis with mononuclear perivascular cuffing. The diagnosis was confirmed by immunohistochemistry, in-situ hybridization, polymerase chain reaction (PCR) and sequencing of PCR products and alignment with known Borna disease virus sequences. Serological screening of the herd was performed. This is the first detailed report of naturally occurring BD in alpacas.

[Proventricular dilatation disease and Avian Bornavirus as a possible cause]

OBJECTIVE

Proventricular Dilatation Disease (PDD) is a very important letal disease in parrots. It affects several psittacine species and is a high risk factor for the health of breeding collections, but is rarely observed in other avian families. To date, the etiology of the disease remained unclear, though a virus infection was always assumed. Recently, a novel virus (Avian Bornavirus [ABV]) was discovered in parrots suffering from PDD so that ABV is now considered as the most likely cause. Despite the fact that clinically healthy birds may be infected with ABV, several studies demonstrate a correlation between ABV-infection and clinically present PDD. Apart from direct virus detection, serological methods allow the demonstration of an infection.

CONCLUSIONS

Currently, Avian Bornavirus is the leading candidate as the aetiologic agent of PDD. Breeding collections and birds planned to be introduced into collections should therefore be investigated by molecular biological and serological methods for the presence of an ABV-infection. The diagnostic value of the demonstration of an ABV-infection for the diagnosis of a clinically present PDD has to be investigated further.