Fetal gene therapy: opportunities and risks

Advances in human prenatal medicine and molecular genetics have allowed the diagnosis of many genetic diseases early in gestation. In-utero transplantation of allogeneic hematopoietic stem cells (HSC) has been successfully used as a therapy in different animal models and recently also in human fetuses. Unfortunately, clinical success of this novel treatment is limited by the lack of donor cell engraftment in non-immunocompromised hosts and is thus restricted to diseases where the fetus is affected by severe immunodeficiency. Gene therapy using genetically modified autologous HSC circumvents allogeneic HLA barriers and constitutes one of the most promising new approaches to correct genetic deficits in the fetus. Recent developments of strategies to overcome failure of efficient transduction of quiescent hematopoietic cells include the use of new vector constructs and transduction protocols. These improvements open new perspectives for gene therapy in general and for prenatal gene transfer in particular. The fetus may be especially susceptible for successful gene therapy due to the immunologic naiveté of the immature hematopoietic system during gestation, precluding an immune reaction towards the transgene. Ethical issues, in particular those regarding treatment safety, must be taken into account before clinical trials with fetal gene therapy in human pregnancies can be initiated.

Sensitive and highly specific quantitative real-time PCR and ELISA for recording a potential transfer of novel DNA and Cry1Ab protein from feed into bovine milk

To address food safety concerns of the public regarding the potential transfer of recombinant DNA (cry1Ab) and protein (Cry1Ab) into the milk of cows fed genetically modified maize (MON810), a highly specific and sensitive quantitative real-time PCR (qPCR) and an ELISA were developed for monitoring suspicious presence of novel DNA and Cry1Ab protein in bovine milk. The developed assays were validated according to the assay validation criteria specified in the European Commission Decision 2002/657/EC. The detection limit and detection capability of the qPCR and ELISA were 100 copies of cry1Ab microL(-1) milk and 0.4 ng mL(-1) Cry1Ab, respectively. Recovery rates of 84.9% (DNA) and 97% (protein) and low (<15%) imprecision revealed the reliable and accurate estimations. A specific qPCR amplification and use of a specific antibody in ELISA ascertained the high specificity of the assays. Using these assays for 90 milk samples collected from cows fed either transgenic (n = 8) or non-transgenic (n = 7) rations for 6 months, neither cry1Ab nor Cry1Ab protein were detected in any analyzed sample at the assay detection limits.

Use of homeopathic preparations in phytopathological models and in field trails: a critical review

Background: The literature on the applications of homeopathy for controlling plant diseases in both plant pathological models and field trials was first reviewed by Scofield in 1984. No other review on homeopathy in plant pathology has been published since, though much new research has subsequently been carried out using more advanced methods. Objectives: To conduct an up-to-date review of the existing literature on basic research in homeopathy using phytopathological models and experiments in the field. Methods: A literature search was carried out on publications from 1969 to 2009, for papers that reported experiments on homeopathy using phytopathological models (in vitro and in planta) and field trials. The selected papers were summarized and analysed on the basis of a Manuscript Information Score (MIS) to identify those that provided sufficient information for proper interpretation (MIS ≥ 5). These were then evaluated using a Study Methods Evaluation Procedure (SMEP). Results: A total of 44 publications on phytopathological models were identified: 19 papers with statistics, 6 studies with MIS ≥ 5. Publications on field were 9, 6 with MIS ≥ 5. In general, significant and reproducible effects with decimal and centesimal potencies were found, including dilution levels beyond the Avogadro's number. Conclusions: The prospects for homeopathic treatments in agriculture are promising, but much more experimentation is needed, especially at a field level, and on potentisation techniques, effective potency levels and conditions for reproducibility. Phytopathological models may also develop into useful tools to answer pharmaceutical questions.

Proton-coupled oligopeptide transporter family SLC15: physiological, pharmacological and pathological implications

Mammalian members of the proton-coupled oligopeptide transporter family (SLC15) are integral membrane proteins that mediate the cellular uptake of di/tripeptides and peptide-like drugs. The driving force for uphill electrogenic symport is the chemical gradient and membrane potential which favors proton uptake into the cell along with the peptide/mimetic substrate. The peptide transporters are responsible for the absorption and conservation of dietary protein digestion products in the intestine and kidney, respectively, and in maintaining homeostasis of neuropeptides in the brain. They are also responsible for the absorption and disposition of a number of pharmacologically important compounds including some aminocephalosporins, angiotensin-converting enzyme inhibitors, antiviral prodrugs, and others. In this review, we provide updated information on the structure-function of PepT1 (SLC15A1), PepT2 (SLC15A2), PhT1 (SLC15A4) and PhT2 (SLC15A3), and their expression and localization in key tissues. Moreover, mammalian peptide transporters are discussed in regard to pharmacogenomic and regulatory implications on host pharmacology and disease, and as potential targets for drug delivery. Significant emphasis is placed on the evolving role of these peptide transporters as elucidated by studies using genetically modified animals. Whenever possible, the relevance of drug-drug interactions and regulatory mechanisms are evaluated using in vivo studies.

Electrophysiological properties of mouse and epitope-tagged human cardiac sodium channel Na v1.5 expressed in HEK293 cells

Background: The pore-forming subunit of the cardiac sodium channel, Na v1.5, has been previously found to be mutated in genetically determined arrhythmias. Na v1.5 associates with many proteins that regulate its function and cellular localisation. In order to identify more in situ Na v1.5 interacting proteins, genetically-modified mice with a high-affinity epitope in the sequence of Na v1.5 can be generated. Methods: In this short study, we (1) compared the biophysical properties of the sodium current (I Na) generated by the mouse Na v1.5 (mNa v1.5) and human Na v1.5 (hNa v1.5) constructs that were expressed in HEK293 cells, and (2) investigated the possible alterations of the biophysical properties of the human Na v1.5 construct that was modified with specific epitopes. Results: The biophysical properties of mNa v1.5 were similar to the human homolog. Addition of epitopes either up-stream of the N-terminus of hNa v1.5 or in the extracellular loop between the S5 and S6 transmembrane segments of domain 1, significantly decreased the amount of I Na and slightly altered its biophysical properties. Adding green fluorescent protein (GFP) to the N-terminus did not modify any of the measured biophysical properties of hNa v1.5. Conclusions: These findings have to be taken into account when planning to generate genetically-modified mouse models that harbour specific epitopes in the gene encoding mNa v1.5.

Earth gravity field recovery using GPS, GLONASS, and SLR satellites

The time variable Earth’s gravity field provides the information about mass transport within the system Earth, i.e., the relationship of mass transport between atmosphere, oceans, and land hydrology. We recover the low-degree parameters of the time variable gravity field using microwave observations from GPS and GLONASS satellites and from SLR data to five geodetic satellites, namely LAGEOS-1/2, Starlette, Stella, and AJISAI. GPS satellites are particularly sensitive to specific coefficients of the Earth's gravity field, because of the deep 2:1 orbital resonance with Earth rotation (two revolutions of the GPS satellites per sidereal day). The resonant coefficients cause, among other, a “secular” drift (actually periodic variations of very long periods) of the semi-major axes of up to 5.3 m/day of GPS satellites. We processed 10 years of GPS and GLONASS data using the standard orbit models from the Center of Orbit Determination in Europe (CODE) with a simultaneous estimation of the Earth gravity field coefficients and other parameters, e.g., satellite orbit parameters, station coordinates, Earth rotation parameters, troposphere delays, etc. The weekly GNSS gravity solutions up to degree and order 4/4 are compared to the weekly SLR gravity field solutions. The SLR-derived geopotential coefficients are compared to monthly GRACE and CHAMP results.

Repeat length and RNA expression level are not primary determinants in CUG expansion toxicity in Drosophila models.

Evidence for an RNA gain-of-function toxicity has now been provided for an increasing number of human pathologies. Myotonic dystrophies (DM) belong to a class of RNA-dominant diseases that result from RNA repeat expansion toxicity. Specifically, DM of type 1 (DM1), is caused by an expansion of CUG repeats in the 3'UTR of the DMPK protein kinase mRNA, while DM of type 2 (DM2) is linked to an expansion of CCUG repeats in an intron of the ZNF9 transcript (ZNF9 encodes a zinc finger protein). In both pathologies the mutant RNA forms nuclear foci. The mechanisms that underlie the RNA pathogenicity seem to be rather complex and not yet completely understood. Here, we describe Drosophila models that might help unravelling the molecular mechanisms of DM1-associated CUG expansion toxicity. We generated transgenic flies that express inducible repeats of different type (CUG or CAG) and length (16, 240, 480 repeats) and then analyzed transgene localization, RNA expression and toxicity as assessed by induced lethality and eye neurodegeneration. The only line that expressed a toxic RNA has a (CTG)(240) insertion. Moreover our analysis shows that its level of expression cannot account for its toxicity. In this line, (CTG)(240.4), the expansion inserted in the first intron of CG9650, a zinc finger protein encoding gene. Interestingly, CG9650 and (CUG)(240.4) expansion RNAs were found in the same nuclear foci. In conclusion, we suggest that the insertion context is the primary determinant for expansion toxicity in Drosophila models. This finding should contribute to the still open debate on the role of the expansions per se in Drosophila and in human pathogenesis of RNA-dominant diseases.

Novel radiotherapy techniques for involved-field and involved-node treatment of mediastinal Hodgkin lymphoma: when should they be considered and which questions remain open?

PURPOSE Hodgkin lymphoma (HL) is a highly curable disease. Reducing late complications and second malignancies has become increasingly important. Radiotherapy target paradigms are currently changing and radiotherapy techniques are evolving rapidly. DESIGN This overview reports to what extent target volume reduction in involved-node (IN) and advanced radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy-compared with involved-field (IF) and 3D radiotherapy (3D-RT)- can reduce high doses to organs at risk (OAR) and examines the issues that still remain open. RESULTS Although no comparison of all available techniques on identical patient datasets exists, clear patterns emerge. Advanced dose-calculation algorithms (e.g., convolution-superposition/Monte Carlo) should be used in mediastinal HL. INRT consistently reduces treated volumes when compared with IFRT with the exact amount depending on the INRT definition. The number of patients that might significantly benefit from highly conformal techniques such as IMRT over 3D-RT regarding high-dose exposure to organs at risk (OAR) is smaller with INRT. The impact of larger volumes treated with low doses in advanced techniques is unclear. The type of IMRT used (static/rotational) is of minor importance. All advanced photon techniques result in similar potential benefits and disadvantages, therefore only the degree-of-modulation should be chosen based on individual treatment goals. Treatment in deep inspiration breath hold is being evaluated. Protons theoretically provide both excellent high-dose conformality and reduced integral dose. CONCLUSION Further reduction of treated volumes most effectively reduces OAR dose, most likely without disadvantages if the excellent control rates achieved currently are maintained. For both IFRT and INRT, the benefits of advanced radiotherapy techniques depend on the individual patient/target geometry. Their use should therefore be decided case by case with comparative treatment planning.

Regulatory sequences of the porcine THBD gene facilitate endothelial-specific expression of bioactive human thrombomodulin in single- and multitransgenic pigs.

BACKGROUND Among other mismatches between human and pig, incompatibilities in the blood coagulation systems hamper the xenotransplantation of vascularized organs. The provision of the porcine endothelium with human thrombomodulin (hTM) is hypothesized to overcome the impaired activation of protein C by a heterodimer consisting of human thrombin and porcine TM. METHODS We evaluated regulatory regions of the THBD gene, optimized vectors for transgene expression, and generated hTM expressing pigs by somatic cell nuclear transfer. Genetically modified pigs were characterized at the molecular, cellular, histological, and physiological levels. RESULTS A 7.6-kb fragment containing the entire upstream region of the porcine THBD gene was found to drive a high expression in a porcine endothelial cell line and was therefore used to control hTM expression in transgenic pigs. The abundance of hTM was restricted to the endothelium, according to the predicted pattern, and the transgene expression of hTM was stably inherited to the offspring. When endothelial cells from pigs carrying the hTM transgene--either alone or in combination with an aGalTKO and a transgene encoding the human CD46-were tested in a coagulation assay with human whole blood, the clotting time was increased three- to four-fold (P<0.001) compared to wild-type and aGalTKO/CD46 transgenic endothelial cells. This, for the first time, demonstrated the anticoagulant properties of hTM on porcine endothelial cells in a human whole blood assay. CONCLUSIONS The biological efficacy of hTM suggests that the (multi-)transgenic donor pigs described here have the potential to overcome coagulation incompatibilities in pig-to-primate xenotransplantation.

Earth Rotation and Gravity Field Parameters from Satellite Laser Ranging

We present the results from a simultaneous estimation of the gravity field, Earth rotation parameters, and station coordinates from combined SLR solutions incorporating up to nine geodetic satellites: LAGEOS-1/2, Starlette, Stella, AJISAI, Beacon-C, Lares, Blits and LARES. These solutions cover all three pillars of satellite geodesy and ensure full consistency between the Earth rotation parameters, gravity field coefficients, and geometry-related parameters. We address benefits emerging from such an approach and discuss particular aspects and limitations of the gravity field recovery using SLR data. The current accuracy of SLR-derived polar motion, by the means of WRMS w.r.t. IERS-08-C04 series, is at a level of 118-149 μas, which corresponds to 4 to 5 mm on the Earth’s surface. The WRMS of SLR-derived Length-of-Day, when the gravity field parameters are simultaneously estimated, is 56 μs/day, corresponding to about 26 mm on the ground, and the mean bias of SLR-derived Length-of-Day is 6.3 μs/day, corresponding to 3 mm.

Investigation of retinal morphology alterations using spectral domain optical coherence tomography in a mouse model of retinal branch and central retinal vein occlusion.

Retinal vein occlusion is a leading cause of visual impairment. Experimental models of this condition based on laser photocoagulation of retinal veins have been described and extensively exploited in mammals and larger rodents such as the rat. However, few reports exist on the use of this paradigm in the mouse. The objective of this study was to investigate a model of branch and central retinal vein occlusion in the mouse and characterize in vivo longitudinal retinal morphology alterations using spectral domain optical coherence tomography. Retinal veins were experimentally occluded using laser photocoagulation after intravenous application of Rose Bengal, a photo-activator dye enhancing thrombus formation. Depending on the number of veins occluded, variable amounts of capillary dropout were seen on fluorescein angiography. Vascular endothelial growth factor levels were markedly elevated early and peaked at day one. Retinal thickness measurements with spectral domain optical coherence tomography showed significant swelling (p<0.001) compared to baseline, followed by gradual thinning plateauing two weeks after the experimental intervention (p<0.001). Histological findings at day seven correlated with spectral domain optical coherence tomography imaging. The inner layers were predominantly affected by degeneration with the outer nuclear layer and the photoreceptor outer segments largely preserved. The application of this retinal vein occlusion model in the mouse carries several advantages over its use in other larger species, such as access to a vast range of genetically modified animals. Retinal changes after experimental retinal vein occlusion in this mouse model can be non-invasively quantified by spectral domain optical coherence tomography, and may be used to monitor effects of potential therapeutic interventions.

Improved star camera attitude data and their effect on the gravity field

Efforts are ongoing to decrease the noise of the GRACE gravity field models and hence to arrive closer to the GRACE baseline. The most significant error sources belong the untreated errors in the observation data and the imperfections in the background models. The recent study (Bandikova&Flury,2014) revealed that the current release of the star camera attitude data (SCA1B RL02) contain noise systematically higher than expected by about a factor 3-4. This is due to an incorrect implementation of the algorithms for quaternion combination in the JPL processing routines. Generating improved SCA data requires that valid data from both star camera heads are available which is not always the case because the Sun and Moon at times blind one camera. In the gravity field modeling, the attitude data are needed for the KBR antenna offset correction and to orient the non-gravitational linear accelerations sensed by the accelerometer. Hence any improvement in the SCA data is expected to be reflected in the gravity field models. In order to quantify the effect on the gravity field, we processed one month of observation data using two different approaches: the celestial mechanics approach (AIUB) and the variational equations approach (ITSG). We show that the noise in the KBR observations and the linear accelerations has effectively decreased. However, the effect on the gravity field on a global scale is hardly evident. We conclude that, at the current level of accuracy, the errors seen in the temporal gravity fields are dominated by errors coming from sources other than the attitude data.

Sustainable Pasture Management : LforS learning and simulation game

Three teams consisting of 2 to 5 persons each play the game. Each team represents a farm. Each team decides jointly on its strategy. In annual meetings in winter, the farm teams jointly discuss, evaluate and decide on how to proceed and actions to be taken. The farms make use of three different pasture areas (village pasture, intensive pasture and summer pasture) for grazing their livestock. The carrying capacity of each pasture area is different and varies according to the season. In each season, the farms have to decide on how many livestock units to graze on which pasture. Overgrazing and pasture degradation occur if the total number of livestock units exceeds the carrying capacity of a specific pasture area. Overgrazing results in a reduction of pasture productivity. To diversify and improve their livelihood strategy farms can make individual investments to increase productivity at the farm level, eg. in fodder production or in income generating activities. At the community level, collective investments can be made which may influence livestock and household economy, e.g. rehabilitate and improve pasture productivity, improve living conditions on remote pastures etc. Events occurring in the course of the game represent different types of (risk) factors such as meteorology, market, politics etc. that may positively or negatively influence livestock production and household economy. A sustainable management of pastures requires that farms actively regulate the development of their herds, that they take measures to prevent pasture degradation and to improve pasture productivity, and that they find a balance between livestock economy and other productive activities. The game has a double aim: a) each farm aims at its economic success and prosperity, and b) the three farm teams jointly have to find and implement strategies for a sustainable use of pasture areas.

Gene flow and the maintenance of species boundaries

Hybrid zones are regions where individuals from genetically differentiated populations meet and mate, resulting in at least some offspring of mixed ancestry. Patterns of gene flow (introgression) in hybrid zones vary across the genome, allowing assessment of the role of individual genes or genome regions in reproductive isolation. Here, we document patterns of introgression between two recently diverged species of field crickets. We sampled at a very fine spatial scale and genotyped crickets for 110 highly differentiated single nucleotide polymorphisms (SNPs) identified through transcriptome scans. Using both genomic and geographic cline analysis, we document remarkably abrupt transitions (<100 m) in allele frequencies for 50 loci, despite high levels of gene flow at other loci. These are among the steepest clines documented for any hybridizing taxa. Furthermore, the cricket hybrid zone provides one of the clearest examples of the semi-permeability of species boundaries. Comparisons between data from the fine-scale transect and data (for the same set of markers) from sampling a much larger area in a different region of the cricket hybrid zone reveal consistent patterns of introgression for individual loci. The consistency in patterns of introgression between these two distant and distinct regions of the hybrid zone suggests that strong selection is acting to maintain abrupt discontinuities within the hybrid zone and that genomic regions with restricted introgression likely include genes that contribute to nonecological prezygotic barriers.

Computational Tools for Stereo and Light Field Photography

This thesis covers a broad part of the field of computational photography, including video stabilization and image warping techniques, introductions to light field photography and the conversion of monocular images and videos into stereoscopic 3D content. We present a user assisted technique for stereoscopic 3D conversion from 2D images. Our approach exploits the geometric structure of perspective images including vanishing points. We allow a user to indicate lines, planes, and vanishing points in the input image, and directly employ these as guides of an image warp that produces a stereo image pair. Our method is most suitable for scenes with large scale structures such as buildings and is able to skip the step of constructing a depth map. Further, we propose a method to acquire 3D light fields using a hand-held camera, and describe several computational photography applications facilitated by our approach. As the input we take an image sequence from a camera translating along an approximately linear path with limited camera rotations. Users can acquire such data easily in a few seconds by moving a hand-held camera. We convert the input into a regularly sampled 3D light field by resampling and aligning them in the spatio-temporal domain. We also present a novel technique for high-quality disparity estimation from light fields. Finally, we show applications including digital refocusing and synthetic aperture blur, foreground removal, selective colorization, and others.