[The DICOM-CD-Project of the German Radiology Association--an overview of the content and results of a pilot study in 2006]. / Das DICOM-CD-Projekt der Deutschen Röntgengesellschaft--eine Ubersicht über die Inhalte und Ergebnisse des Pilottests 2006.

DICOM-CDs are frequently used for medical image data transfer. Many different potential advantages are known, such as improved image quality, handling simplification, and cost optimization. However, there are numerous restrictions in the daily routine. While testing DICOM-CDs at the 2006 German Radiology Congress, we found that more than 70 % of CDs have discrepancies with respect to data structure or content. The German Radiological Association and OFFIS started an initiative to improve the quality of DICOM-CDs. There are three main objectives: To provide requirements for vendors of CD-writing systems, to establish user guidelines for the handling of DICOM-CDs, and to develop a test procedure for DICOM-CDs. Radiologists using such systems should be aware of these developments and use them for RFP's.

[Standards for safe data exchange in teleradiology exemplified by image and report distribution]. / Standards für den sicheren Datenaustausch in der Teleradiologie am Beispiel der Bild- und Befundverteilung.

The use of telemedicine is becoming indispensable for a continuous and economical delivery of a high quality of care. However, data protection requirements have to be considered. For the selection of solutions, vendor-independent components based on standards are a prerequisite for a seamless integration into the existing, often heterogeneous, IT infrastructure. The "Internet protocol" TCP/IP and the DICOM standard with it's new security extensions form the basis for an internationally standardized and accepted procedure for a secure interchange of radiological images beyond platform boundaries.

Cardiac digital image loops and multimedia reports over the internet using DICOM.

The authors define an open, scaleable telemedicine architecture to reduce the time of reports delivery and consultation; increasing their simplicity via introducing common image presentation, storage and telecommunication formats and methods for telecardiology. They've developed a software application to implement it introducing the most appropriate digital imaging methods and formats using the latest available technology.

DICOM extensions for narrow-band networks.

DICOM is today's de-facto standard for exchanging medical images. Since new image acquisition devices produce more and more image and non-image data, image compression has become an important part of the standard. However, the compression of non-pixel data also stored in DICOM data sets has been disregarded up to now. In the scope of an EU research project we have examined a large amount of real-world DICOM images to test whether or not there is a potential for compressing the non-pixel attributes. Especially for use with narrow-band networks extensions as proposed in this paper could be a solution to save valuable bandwidth.

New DICOM extensions for softcopy and hardcopy display consistency.

The DICOM standard defines in detail how medical images can be communicated. However, the rules on how to interpret the parameters contained in a DICOM image which deal with the image presentation were either lacking or not well defined. As a result, the same image frequently looks different when displayed on different workstations or printed on a film from various printers. Three new DICOM extensions attempt to close this gap by defining a comprehensive model for the display of images on softcopy and hardcopy devices: Grayscale Standard Display Function, Grayscale Softcopy Presentation State and Presentation Look Up Table.

Tuber-specific expression of a yeast invertase and a bacterial glucokinase in potato leads to an activation of sucrose phosphate synthase and the creation of a sucrose futile cycle.

Fluxes were investigated in growing tubers from wild-type potato (Solanum tuberosum L. cv.Desiree) and from transformants expressing a yeast invertase in the cytosol under the control of the tuber-specific patatin promoter either alone (EC 3.2.1.26;U-IN2-30) or in combination with a Zymomonas mobilis glucokinase (EC 2.7.1.2; GK3-38) by supplying radiolabelled [14C]sucrose, [14C]glucose or [14C]fructose to tuber discs for a 90-min pulse and subsequent chase incubations of 4 and 12 h, and by supplying [14C]fructose for 2 h and 4 h to intact tubers attached to the mother plant. Contrary to the expectation that this novel route for sucrose degradation would promote starch synthesis,the starch content decreased in the transgenic lines.Labelling kinetics did not reveal whether this was due to changes in the fluxes into or out of starch. However,they demonstrated that glycolysis is enhanced in the transgenic lines in comparison to the wild type. There was also a significant stimulation of sucrose synthesis,leading to a rapid cycle of sucrose degradation and resynthesis. The labelling pattern indicated that sucrose phosphate synthase (SPS; EC 2.4.1.14) was responsible for the enhanced recycling of label into sucrose. In agreement, there was a 4-fold and 6-fold increase in the activation status of SPS in U-IN2-30 and GK3-38,respectively, and experiments with protein phosphatase inhibitors indicated that this activation involves enhanced dephosphorylation of SPS. It is proposed that this activation of SPS is promoted by the elevated glucose 6-phosphate levels in the transgenic tubers.These results indicate the pitfalls of metabolic engineering without a full appreciation of the metabolic system and regulatory circuits present in the tissue under investigation.

Combined expression of glucokinase and invertase in potato tubers leads to a dramatic reduction in starch accumulation and a stimulation of glycolysis.

The original aim of this work was to increase starch accumulation in potato tubers by enhancing their capacity to metabolise sucrose.We previously reported that specific expression of a yeast invertase in the cytosol of tubers led to a 95% reduction in sucrose content, but that this was accompanied by a larger accumulation of glucose and a reduction in starch. In the present paper we introduced a bacterial glucokinase from Zymomonas mobilis into an invertase-expressing transgenic line, with the intention of bringing the glucose into metabolism. Transgenic lines were obtained with up to threefold more glucokinase activity than in the parent invertase line and which did not accumulate glucose. Unexpectedly, there was a further dramatic reduction in starch content, down to 35% of wild-type levels. Biochemical analysis of growing tuber tissue revealed large increases in the metabolic intermediates of glycolysis, organic acids and amino acids,two- to threefold increases in the maximum catalytic activities of key enzymes in the respiratory pathways, and three- to fivefold increases in carbon dioxide production.These changes occur in the lines expressing invertase,and are accentuated following introduction of the second transgene, glucokinase. We conclude that the expression of invertase in potato tubers leads to an increased flux through the glycolytic pathway at the expense of starch synthesis and that heterologous overexpression of glucokinase enhances this change in partitioning.

Two cDNAs from potato are able to complement a phosphate uptake-deficient yeast mutant: identification of phosphate transporters from higher plants.

Acquisition as well as translocation of phosphate are essential processes for plant growth. In many plants, phosphate uptake by roots and distribution within the plant are presumed to occur via a phosphate/proton cotransport mechanism. Here, we describe the isolation of two cDNAs, StPT1 and StPT2, from potato (Solanum tuberosum) that show homology to the phosphate/proton cotransporter PHO84 from the yeast Saccharomyces cerevisiae. The predicted products of both cDNAs share 35% identity with the PHO84 sequence. The deduced structure of the encoded proteins revealed 12 membrane-spanning domains with a central hydrophilic region. The molecular mass was calculated to be 59 kD for the StPT1 protein and 58 kD for the StPT2 protein. When expressed in a PHO84-deficient yeast strain, MB192, both cDNAs complemented the mutant. Uptake of radioactive orthophosphate by the yeast mutant expressing either StPT1 or StPT2 was dependent on pH and reduced in the presence of uncouplers of oxidative phosphorylation, such as 2,4-dinitrophenol or carbonyl cyanide m-chlorophenylhydrazone. The K(m) for Pi uptake of the StPT1 and StPT2 proteins was determined to be 280 and 130 microM, respectively. StPT1 is expressed in roots, tubers, and source leaves as well as in floral organs. Deprivation of nitrogen, phosphorus, potassium, and sulfur changed spatial expression as well as the expression level of StPT1. StPT2 expression was detected mainly in root organs when plants were deprived of Pi and to a lesser extent under sulfur deprivation conditions. No expression was found under optimized nutrition conditions or when other macronutrients were lacking.

Cutting, ageing and expression of plant membrane transporters.

The activity and the expression of sucrose, hexose and amino acid transporters were studied with fresh, cut or aged tissues and plasma membrane vesicles (PMV) of mature sugar beet (Beta vulgaris L.) leaves. Cutting and ageing both induced an increase of the transcripts coding for sucrose transporters and hexose transporters. No significant effect could be detected on the amino acid transporter transcripts with the probe used (aap1). A polyclonal serum directed against the Arabidopsis thaliana sucrose transporter (AtSUC1) reacted with a 42 kDa band of the sugar beet PMV, confirming previous biochemical identification of this band as a sucrose transporter. ELISA assays run with microsomal fractions and PMV using the AtSUC1 sucrose transporter probe indicated that ageing, and to a lesser extent cutting, increased the amount of sucrose transporter present in the plasma membrane. However, while cutting strongly stimulated proton-motive force driven uptake of sucrose in PMV, ageing only resulted in a slight stimulation. These data give evidence for transcriptional, post-transcriptional and post-translational controls of the activity of the sucrose transporter by mechanical treatments. Proton-motive force driven uptake of 3-O-methylglucose and valine in PMV was strongly stimulated in PMV from aged tissues, although previous data had shown that cutting did not affect theses processes. Therefore, the plant cells possess various levels of control mechanisms that allow them to regulate fluxes of the main assimilates across the plasma membrane when their natural environment is directly or indirectly altered.