Effects of drought and N level on the interactions of the root hemiparasite Rhinanthus alectorolophus with a combination of three host species.

Increasing nitrogen deposition and more frequent drought events are likely to change plant interactions in natural grasslands. Both factors may also influence the interactions between hemiparasitic plants, regarded as keystone species in many grasslands, and their host species. We grew a combination of three suitable hosts, a grass, a forb and a legume, with and without the hemiparasite Rhinanthus alectorolophus at three levels of nitrogen (N) and two levels of water availability in a factorial design. Biomass of the hemiparasite and host community increased with N level and was reduced by drought to a similar degree. Larger plants in fertilised pots started to wilt earlier, and the presence of a hemiparasite further increased drought sensitivity. The hemiparasite strongly reduced biomass of the host community and overall productivity, and affected the competitive balance among host plants because it particularly reduced biomass of the dominant grass. These effects were the opposite of those of high N. The hemiparasite increased the root mass fraction of the hosts at all levels of N and water availability, indicating that the effect of the hemiparasite on the hosts was mainly due to loss of belowground resources. Our results indicate that hemiparasites will not always respond more strongly to increased N availability and drought than autotrophic plants, and that hemiparasites can have similarly strong effects on grassland communities as soil fertility and drought. By preferentially attacking dominant species the hemiparasites might alleviate the negative effects of nutrient enrichment on grassland diversity.

Transgenerational plasticity in Silene vulgaris in response to three types of stress.

The environment experienced by plants can influence the phenotype of their offspring. Such transgenerational plasticity can be adaptive when it results in higher fitness of the offspring under conditions correlated with those experienced by the mother plant. However, it has rarely been tested if such anticipatory parental effects may be induced with different environments. We grew clonal replicates of Silene vulgaris under control conditions and three types of stress (nutrient deficiency, copper addition and drought), which are known from natural populations of the species. We then subjected offspring from differently treated mother plants to each of the different stress treatments to analyse the influence of maternal and offspring environment on performance and several functional traits. Current stress treatments strongly influenced biomass and functional traits of the plants, mostly in line with responses predicted by the theory of functional equilibrium. Plant performance was also influenced by maternal stress treatments, and some effects independent of initial size differences remained until harvest. In particular, stressed mothers produced offspring of higher fitness than control plants. However, there was no evidence for treatment-specific adaptive transgenerational plasticity, as offspring from a mother plant that had grown in a specific environment did not grow better in that environment than other plants. Our results indicate that the maternal environment may affect offspring traits and performance, but also that this transgenerational plasticity is not necessarily adaptive.

Automatic path proposal computation for CT-guided percutaneous liver biopsy.

PURPOSE: To evaluate feasibility of automatic software-based path proposals for CT-guided percutaneous biopsies. METHODS: Thirty-three patients (60 [Formula: see text] 12 years) referred for CT-guided biopsy of focal liver lesions were consecutively included. Pre-interventional CT and dedicated software (FraunhoferMeVis Pathfinder) were used for (semi)automatic segmentation of relevant structures. The software subsequently generated three path proposals in downward quality for CT-guided biopsy. Proposed needle paths were compared with consensus proposal of two experts (comparable, less suitable, not feasible). In case of comparable results, equivalent approach to software-based path proposal was used. Quality of segmentation process was evaluated (Likert scale, 1 [Formula: see text] best, 6 [Formula: see text] worst), and time for processing was registered. RESULTS: All biopsies were performed successfully without complications. In 91 % one of the three automatic path proposals was rated comparable to experts' proposal. None of the first proposals was rated not feasible, and 76 % were rated comparable to the experts' proposal. 7 % automatic path proposals were rated not feasible, all being second choice ([Formula: see text]) or third choice ([Formula: see text]). In 79 %, segmentation at least was good. Average total time for establishing automatic path proposal was 42 [Formula: see text] 9 s. CONCLUSION: Automatic software-based path proposal for CT-guided liver biopsies in the majority provides path proposals that are easy to establish and comparable to experts' insertion trajectories.

MR first pass perfusion of benign and malignant cardiac tumours-significant differences and diagnostic accuracy.

OBJECTIVES: To determine the diagnostic value of magnetic resonance (MR) first pass perfusion in the differentiation of benign and malignant cardiac tumours. METHODS: 24 patients with cardiac tumours (11 malignant, histopathological correlation present in all cases) were examined using MRI. In addition to morphological sequences a saturation-recovery T1w-GRE technique was implemented for tumour perfusion. The maximum relative signal enhancement (RSE[%]) and the slope of the RSE(t)-curve (slopeRSE[%/s]) of tumour tissue were assessed. A t-test was used to identify significant differences between benign and malignant tumours. Sensitivities and specificities were calculated for detection of malignant lesions and were compared with the sensitivity and specificity based on solely morphological image assessment. RESULTS: The RSE and slopeRSE of malignant cardiac tumours were significantly higher compared with benign lesions (p < 0.001 and p < 0.001). The calculated sensitivities and specificities of RSE and slopeRSE for identification of malignant lesions were 100% and 84.6% and 100% and 92.3%, respectively with cut-off values of 80% and 6%/s. The sensitivity and specificity for identification of malignant lesions on the basis of morphological imaging alone were 90.9% and 69.2%. CONCLUSIONS: With first pass perfusion, malignant cardiac masses can be identified with higher sensitivity and specificity compared with morphological image assessment alone.

Contrast enhanced IR-SSFP examination compared with T1-weighted turbo spin-echo imaging of cardiac tumors and tumorlike lesions.

PURPOSE: To show that the use of an early and delayed contrast enhanced multislice inversion recovery steady state free precession (SS-IR-SSFP) is a valuable substitute for conventional post-contrast fat saturated turbo spin-echo (TSE) T1-weighted images in the assessment of cardiac tumors. MATERIALS AND METHODS: 34 consecutive patients referred for MRI in order to assess cardiac tumors were examined. Shortly after administration of gadopenetate dimeglumine (Gd-DTPA) images were obtained using a SS-IR-SSFP sequence. The inversion time (TI) was set at 350ms to achieve a good demarcation of intracavitary tumor spread. Hereafter 9 slices of a T1w TSE sequence were obtained. Finally a SS-IR-SSFP sequence with an optimized TI to null normal myocardium was employed. Quantitative comparisons were performed by calculating contrast to noise ratios of tumor/myocardium (CNR(tumor/myo)) and CNR of tumor/left ventricular cavity (CNR(tumor/LVC)). Image quality was assessed regarding overall image quality, artifacts and tumor conspicuity. RESULTS: Neither calculation of CNR(tumor/LVC) when comparing the early IR-SSFP and T1w TSE, nor calculation of CNR(tumor/myo) when comparing the late IR-SSFP and T1w TSE sequence resulted in statistically significant differences. However, qualitative assessments revealed significant superior results for the early and the late IR-SSFP images compared to the T1-weighted TSE images (p<0.001). CONCLUSIONS: Image quality and tumor conspicuity were superior and image degradation by artifacts was less on IR-SSFP images compared to TSE images without loss of CNR. Thus the use of IR-SSFP sequences is an attractive alternative imaging method compared to post-contrast T1w TSE imaging in the assessment of cardiac tumors.

[Therapy of peripheral vessel stenosis and occlusion in patients with thromboangiitis obliterans]. / Therapie peripherer Gefäßstenosen und -verschlüsse bei Thromboangiitis obliterans.

Vasculitis consists of a group of diseases characterized by an inflammatory process of the vessel wall. There is a wide variation in symptoms and almost any organ or tissue can be affected. Thromboangiitis obliterans (TAO; also known as Buerger's disease) is a special form of vasculitis with recurring inflammation and thrombosis of small and medium size arteries and veins of the hands and feet. To date the etiology still remains unclear but there is a strong association with the use of tobacco products. Ulcerations and gangrene of the extremities are common complications often resulting in the need for amputation of the extremity involved. Treatment of TAO includes both surgical and non-surgical methods but there is still no agreement concerning the optimal treatment strategy. In this contribution the advantages and disadvantages of different treatment options will be addressed and representative cases will be discussed.

[Cardiac functional analysis with MRI]. / Kardiale Funktionsanalyse mittels MRT.

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Even in the 21(st) century CVD will still be the most frequent cause of morbidity and mortality. Precise evaluation of cardiac function is therefore mandatory for therapy planning and monitoring. In this article the contribution of MRI-based analysis of cardiac function will be addressed. Nowadays cine-MRI is considered as the standard of reference (SOR) in cardiac functional analysis. ECG-triggered steady-state free precession (SSFP) sequences are mainly used as they stand out due to short acquisition times and excellent contrast between the myocardium and the ventricular cavity. An indispensible requirement for cardiac functional analysis is an exact planning of the examination and based on that the coverage of the whole ventricle in short axial slices. By means of dedicated post-processing software, manual or semi-automatic segmentation of the endocardial and epicardial contours is necessary for functional analysis. In this way end-diastolic volume (EDV), end-systolic volume (ESV) and the ejection fraction (EF) are defined and regional wall motion abnormalities (RWMA) can be detected.

[Late gadolinium enhancement in the diagnostics of ischemic heart disease: technical principles, contrast optimization and clinical application]. / Late-Gadolinium-Enhancement in der Diagnostik der koronaren Herzerkrankung : Technische Grundlagen, Kontrastoptimierung und klinische Anwendung.

BACKGROUND: The purpose of the study was to explore a "dark blood" technique and to compare it with a standard inversion recovery gradient echo (IR GRE) sequence in the visualization of myocardial infarction. PATIENTS AND METHODS: A total of 9 patients were examined with standard IR GRE and a "dark blood" sequence 15 mins after contrast medium application (0.2 mmol/kg body weight gadobenate dimeglumine). Contrast-to-noise ratios (CNR) were calculated for each sequence. RESULTS: The CNR(inf-lvc) was significantly higher in the "dark blood" technique compared to the IR GRE sequence, while the CNR(inf-myo) was significantly lower. CONCLUSIONS: Small subendocardial infarctions may be easier to detect with the "dark blood" technique. However, the standard IR GRE sequence is superior in the demarcation of infarctions in relation to the myocardium and cannot be replaced by the "dark blood" technique.

Single-detector micro-electro-mechanical scanning grating spectrometer.

A compact, robust grating spectrometer based on an optimised micro-electro-mechanical grating mirror component has been developed, built, and characterised. The application of an oscillating reflection grating micro-mirror component as scanning dispersive element in a modified Czerny-Turner monochromator layout enables the design of compact grating spectrometers capable of acquiring full spectra using a single detector element. Designed for a wavelength range between 1200 and 1900 nm, the spectrometer features a spectral resolution of 10 nm with wavelength stability better than +/-0.5 nm. One-hundred scan spectra can be acquired in less than one second, or spectral changes can be monitored at time a resolution of less than 10 ms. In combination with a fibre-optic interface and a typical weight of less than 1 kg, this makes this novel type of fully portable micro-electro-mechanical near-IR scanning spectrometer an interesting alternative to existing spectrometers and opens a range of new applications, in particular the detection of major and minor components in the near-IR.