[Health economic evaluation of rehabilitative short-term care : Analysis of the costs of geriatric patients with and without rehabilitative short-term care after inpatient hospital stay]. / Gesundheitsökonomische Evaluation einer rehabilitativen Kurzzeitpflege : Ermittlung der Kosten von geriatrischen Patienten mit und ohne rehabilitative Kurzzeitpflege nach stationärem Krankenhausaufenthalt.

BACKGROUND: Geriatric patients requiring rehabilitation and admitted to short-term care after an acute inpatient hospital stay seldom receive rehabilitative services later. Rehabilitative short-term care (REKUP) supplements short-term care with rehabilitative measures, aiming to prevent functional restrictions and long-term care. STUDY OBJECTIVE: To conduct a cost and cost-effectiveness analyses of REKUP and provide data for a nationwide rollout. MATERIAL AND METHODS: A non-randomized controlled prospective study was carried out. The intervention group (IG) was paired 1:2 with a control group (KG), resulting in the formation of three collectives with follow-up periods of either 30, 90 or 180 days (each with IG and KG). Using administrative claims data from the AOK Baden-Württemberg, the mean total costs from the perspective of the health insurance were calculated. A potential impact of the intervention on costs was analyzed using the difference in differences approach. RESULTS: The analysis comprised 129 patients (IG 43; KG 86). During the follow-up periods, the IG presented higher rates of rehabilitation and lower rates of long-term care and mortality. Regarding costs, no statistically significant differences were found between the IG and KG in any of the three collectives. For nursing care and medication costs, costs were significantly higher in the follow-up period for the KG, whereas costs for rehabilitation were significantly higher for the IG (p < 0.001). DISCUSSION: Patients receiving REKUP utilize rehabilitation services more often and have a lower likelihood of requiring nursing care or dying with no statistically significant differences in costs. There are potential advantages of REKUP in the target population, which warrant further investigation due to methodological limitations.

Upscaling e-mental health in Europe: a six-country qualitative analysis and policy recommendations from the eMEN project.

E-mental health (eMH) encompasses the use of digital technologies to deliver, support, or enhance mental health services. Despite the growing evidence for the effectiveness of eMH interventions, the process of implementation of eMH solutions in healthcare remains slow throughout Europe. To address this issue, the e-Mental Health Innovation and Transnational Implementation Platform North-West Europe (eMEN) project was initiated to increase the dissemination and quality of eMH services in Europe. In this project, status analyses regarding eMH in the six participating countries (i.e., Belgium, France, Germany, Ireland, The Netherlands, and the UK) were conducted and eight recommendations for eMH were developed. Expert teams from the six participating countries conducted status analyses regarding the uptake of eMH based on a narrative literature review and stakeholder interviews. Based on these status analyses, the eMEN consortium developed eight policy recommendations to further support the implementation of eMH in Europe. The status analyses showed that the participating countries are in different stages of implementing eMH into mental healthcare. Some barriers to implementing eMH were common among countries (e.g., a limited legal and regulatory framework), while others were country-specific (e.g., fragmented, federal policies). The policy recommendations included fostering awareness, creating strong political commitment, and setting reliable standards related to ethics and data security. The eMEN project has provided the initial recommendations to guide political and regulatory processes regarding eMH. Further research is needed to establish well-tailored implementation strategies and to assess the generalizability of the recommendations beyond the countries involved in the eMEN project.

Conserved Senescence Associated Genes and Pathways in Primary Human Fibroblasts Detected by RNA-Seq.

Cellular senescence correlates with changes in the transcriptome. To obtain a complete view on senescence-associated transcription networks and pathways, we assessed by deep RNA sequencing the transcriptomes of five of the most commonly used laboratory strains of human fibroblasts during their transition into senescence. In a number of cases, we verified the RNA-seq data by real-time PCR. By determining cellular protein levels we observed that the age-related expression of most but not all genes is regulated at the transcriptional level. We found that 78% of the age-affected differentially expressed genes were commonly regulated in the same direction (either up- or down-regulated) in all five fibroblast strains, indicating a strong conservation of age-associated changes in the transcriptome. KEGG pathway analyses confirmed up-regulation of the senescence-associated secretory phenotype and down-regulation of DNA synthesis/repair and most cell cycle pathways common in all five cell strains. Newly identified senescence-induced pathways include up-regulation of endocytotic/phagocytic pathways and down-regulation of the mRNA metabolism and the mRNA splicing pathways. Our results provide an unprecedented comprehensive and deep view into the individual and common transcriptome and pathway changes during the transition into of senescence of five human fibroblast cell strains.

Impact of magnification views on the characterization of microcalcifications in digital mammography.

PURPOSE: To evaluate the additional benefit of true geometric (air-gap) magnification views for the characterization of microcalcifications in digital mammography. MATERIALS AND METHODS: After ethical approval, we retrospectively reviewed patient records to identify 100 patients with suspicious microcalcifications (35 malignant, 65 benign) who had a standard digital mammography and an additional digital magnification view in the same projection within three months. All images were obtained using an amorphous silicon-based full-field digital system (Senographe 2000 D, GE Healthcare, Chalfont St. Giles, UK). Images were independently analyzed by six board-certified radiologists. The probability of malignancy was estimated using first standard contact mammography alone (MG) and then mammography in combination with the magnification view (MG+MAG) using a modified Breast Imaging Reporting and Data System (BI-RADS) classification system and a percentage scale. Results were compared using receiver operating characteristic (ROC) analysis. In addition, readers assessed the subjective visibility of the calcifications. RESULTS: For all six readers combined, the area under the curve (AUC) was 0.664 ±â€Š0.052 for MG and 0.813 ±â€Š0.042 for MG + MAG, resulting in a statistically significant improvement of 0.148 ±â€Š0.120. Each reader had a higher AUC for MG + MAG than MG, with the improvement being statistically significant in four of the six readers. In 76.34 % of the cases, MG + MAG resulted in better visibility of calcifications compared with mammography alone. In 33 % slightly more and in 39 % significantly more calcifications were found. CONCLUSION: Even in digital mammography with the option of using electronic magnification (zoom) at the viewing workstation, true geometric (air-gap) magnification views remain important for the visibility and correct classification of microcalcifications and for the assessment of their extent.

Esperanto for histones: CENP-A, not CenH3, is the centromeric histone H3 variant.

The first centromeric protein identified in any species was CENP-A, a divergent member of the histone H3 family that was recognised by autoantibodies from patients with scleroderma-spectrum disease. It has recently been suggested to rename this protein CenH3. Here, we argue that the original name should be maintained both because it is the basis of a long established nomenclature for centromere proteins and because it avoids confusion due to the presence of canonical histone H3 at centromeres.

Image quality and radiation exposure in 320-row temporal bone computed tomography.

OBJECTIVES: The aim was to define image quality and radiation exposure in the recently introduced 320-row CT of the temporal bone (tb) in comparison to a 16-row tb CT. METHODS: A cadaveric head phantom was used for repeated tb volume CT studies (80-120 kV, 25-150 mAs), performed in a 320-row scanner (single rotation, 0.5 mm slice thickness, kernel FC 51) in comparison to 16-row helical CT using standard acquisition parameters (SAP) of 120 kV and 75 mAs (kernel FC 53). Qualitative image evaluation was performed by two radiologists using a 5-point visual analogue scale. Image noise (D(SD)) was determined by region of interest (ROI) based measurements in cadaveric as well as water phantom studies. Dosimetric measurements of the effective dose (ED) and organ dose (OD) of the lens were performed. RESULTS: Image quality of 320-row tb CT was equivalent to 16-row CT for SAP scans, resulting in image noise levels (D(SD) 16-/320-row) of 109/237 and 206/446 for air and bone respectively. D(SD) differences were predominantly (>90%) attributable to the different kernels available for tb studies in 16- and 320-row CT. Radiation exposure for 16-/320-row SAP scans amounted to 0.36/0.30 mSv (ED) and 10.0/8.4 mGy (lens dose). CONCLUSION: 320-row volume acquisition in tb CT delivers equivalent image quality to 16-row CT while decreasing radiation exposure figures by one sixth. Image noise increase in 320-row CT is negligible with respect to image quality.

Dose exposure of patients undergoing comprehensive stroke imaging by multidetector-row CT: comparison of 320-detector row and 64-detector row CT scanners.

BACKGROUND AND PURPOSE: Recently introduced 320-detector row CT enables whole brain perfusion imaging compared to a limited scanning area in 64-detector row CT. Our aim was to evaluate patient radiation exposure in comprehensive stroke imaging by using multidetector row CT consisting of standard CT of the head, CTA of cerebral and cervical vessels, and CTP. MATERIAL AND METHODS: Organ doses were measured by using LiF-TLDs located at several organ sites in an Alderson-Rando phantom. Effective doses were derived from these measurements. Stroke protocols including noncontrast head CT, CTA of cerebral and cervical vessels, and CTP were performed on 320- and 64-detector row scanners. RESULTS: Measured effective doses for the different scanning protocols ranged between 1.61 and 4.56 mSv, resulting in an effective dose for complete stroke imaging of 7.52/7.54 mSv (m/f) for 64-detector row CT and 10.56/10.6 mSv (m/f) for 320-detector row CT. The highest organ doses within the area of the primary beam were measured in the skin (92 mGy) and cerebral hemispheres (69.91 mGy). Use of an eye-protection device resulted in a 54% decrease of the lens dose measured for the combo protocol for whole-brain perfusion with the 320-detector row CT scanner. CONCLUSIONS: Phantom measurements indicate that comprehensive stroke imaging with multidetector row CT may result in effective radiation doses from 7.52 mSv (64-detector row CT) to 10.6 mSv (320-detector row CT). The technique of 320-detector row CT offers additional information on the time course of vascular enhancement and whole-brain perfusion. Physicians should weigh the potential of the new technique against the higher radiation dose that is needed. Critical doses that would cause organ damage were not reached.

Linker histone H1 is present in centromeric chromatin of living human cells next to inner kinetochore proteins.

The vertebrate kinetochore complex assembles at the centromere on alpha-satellite DNA. In humans, alpha-satellite DNA has a repeat length of 171 bp slightly longer than the DNA in the chromatosome containing the linker histone H1. The centromere-binding protein CENP-B binds specifically to alpha-satellite DNA with properties of a centromeric-linker histone. Here, we analysed if linker histone H1 is present at or excluded from centromeric chromatin by CENP-B. By immunostaining we detected the presence, but no enrichment or depletion of five different H1 subtypes at centromeric chromatin. The binding dynamics of H1 at centromeric sites were similar to that at other locations in the genome. These dynamics did not change in CENP-B depleted cells, suggesting that CENP-B and H1 co-exist in centromeric chromatin with no or little functional overlap. By bimolecular fluorescence complementation (BiFC) and Förster resonance energy transfer (FRET), we revealed that the linker histone H1 subtypes H1 degrees and H1.2 bind to centromeric chromatin in interphase nuclei in direct neighbourhood to inner kinetochore proteins.

320-slice CT neuroimaging: initial clinical experience and image quality evaluation.

The aim of this study was to report initial clinical experience with a 320-slice CT scanner and to perform an image quality evaluation. 26 patients with presumptive cerebrovascular pathology underwent 320-slice CT. Single-rotation CT of the head, incremental CT angiography (three-dimensional (3D) CTA) as well as four-dimensional whole-brain CTA (4D CTA) and whole-brain CT perfusion (CTP) were performed and the resulting images were assessed for quality and compared with those obtained with 64-slice CT protocols. 320-slice CT neuroimaging could be performed in all cases. The image quality of 320-slice CT of the head and 3D CTA was inferior to that of the 64-slice protocols. The image quality of 4D 320-slice CTA was rated as inferior to both 320- and 64-slice 3D CTA. 4D CTA-CTP imaging added information with pivotal clinical implications. 320-slice CT neuroimaging is feasible technique that permits whole-brain 4D imaging and has the potential to identify pathologies with altered haemodynamics. However, image quality is a limitation of this technique at present.

Central pontine myelinolysis despite slow sodium rise in a case of severe community-acquired hyponatraemia.

The management of severe hyponatraemia is a challenging task for intensivists. It should be based on underlying pathophysiology, especially the duration of hyponatraemia (acute vs. chronic) and the presence or absence of severe neurologic symptoms. We describe a case of severe community-acquired hyponatraemia in which central pontine myelinolysis developed several days after discharge from the intensive care unit, despite a gradual increase of plasma sodium levels during the intensive care unit stay.

GJA12 mutations are a rare cause of Pelizaeus-Merzbacher-like disease.

BACKGROUND: Pelizaeus-Merzbacher-like disease (PMLD) is a genetically heterogeneous disorder within the group of hypomyelinating leukoencephalopathies. Mutations of the gap junction protein alpha 12 (GJA12) gene are known to cause one autosomal recessive PMLD form. Few patients with GJA12 mutated PMLD have been reported, and to date, the frequency as well as the genotypic and phenotypic spectrum of GJA12 related PMLD is unclear. METHODS: We report mutation analysis of the GJA12 gene in a clinical and radiologic well-characterized multiethnic cohort of 193 patients with PMLD from 182 families. RESULTS AND CONCLUSIONS: Only 16 patients (8.3%) from 14 families (7.7%) carry GJA12 mutations including five families where we detected only one mutated allele. Among those, we identified 11 novel alterations. Thus, GJA12 mutations are a rather rare cause for Pelizaeus-Merzbacher-like disease. The clinical phenotype of patients with a GJA12 mutation was evaluated and is overall comparable to the clinical features seen in mild forms of proteolipid protein 1 (PLP1) related disorder but with better cognition and earlier signs of axonal degeneration.

Escherichia coli low-copy-number plasmid R1 centromere parC forms a U-shaped complex with its binding protein ParR.

The Escherichia coli low-copy-number plasmid R1 contains a segregation machinery composed of parC, ParR and parM. The R1 centromere-like site parC contains two separate sets of repeats. By atomic force microscopy (AFM) we show here that ParR molecules bind to each of the 5-fold repeated iterons separately with the intervening sequence unbound by ParR. The two ParR protein complexes on parC do not complex with each other. ParR binds with a stoichiometry of about one ParR dimer per each single iteron. The measured DNA fragment lengths agreed with B-form DNA and each of the two parC 5-fold interon DNA stretches adopts a linear path in its complex with ParR. However, the overall parC/ParR complex with both iteron repeats bound by ParR forms an overall U-shaped structure: the DNA folds back on itself nearly completely, including an angle of approximately 150 degrees . Analysing linear DNA fragments, we never observed dimerized ParR complexes on one parC DNA molecule (intramolecular) nor a dimerization between ParR complexes bound to two different parC DNA molecules (intermolecular). This bacterial segrosome is compared to other bacterial segregation complexes. We speculate that partition complexes might have a similar overall structural organization and, at least in part, common functional properties.

[Mammography screening in Germany]. / Mammographiescreening in Deutschland.

Available data suggest that early detection of breast cancer by mammography screening can reduce mortality by about 25%. Intensified monitoring of women with a family history of breast cancer and regular general screening have recently been introduced in Germany. The screening program is expected to be fully established by 2008. Following its successful introduction (participation rates between 65 and 80%), the German screening program will be conducted and evaluated in accordance with the European guidelines. At least in the screening trials that were conducted prior to the now established screening program the quality criteria were more than fulfilled (e.g. cancer detection rate in Bremen 8.7, Wiesbaden 9.4, Weser-Ems region 8.3/1000). Additional parameters that can be taken into account for quality assurance are the overdiagnosis bias, lead time bias, length bias and selection bias. Moreover, there are some factors that are specific to the German program compared with the breast cancer screening programs already established in other countries. One of these is the intensified screening program for high-risk women (ca. 5% of all carcinomas) and as a result fewer women with an increased genetic risk of breast cancer will be represented in the general screening program. The German screening program involves only a few university centers and hospital-based physicians, which may have adverse effects on research and development as well as mammography training in the future. Therefore, the screening program should also provide for the investigation of new techniques or emerging techniques (e.g. CAD systems in screening mammography) in the future.

The influence of different cultivation conditions on the metabolic functionality of encapsulated primary hepatocytes.

The clinical application of bioartificial liver support systems (BALS) is still limited because of technical problems associated with the storage, transport and scale-up of common systems. The encapsulation of primary hepatocytes could solve these problems since the scale-up depends only on the number of the beads and encapsulation leads to protection of the cells during the process of freezing and thawing. Many efforts have been made to find an appropriate material for the encapsulation of primary hepatocytes in terms of mechanical resistance as well as appropriate bio- and hemo-compatibility. This study focuses on the improvement of the metabolic functionality of encapsulated primary hepatocytes. A comparison between two different cultivation models showed that dynamic cultivation conditions lead to a 20.4-fold increase in the albumin production and a 5.21-fold increase in the urea synthesis of encapsulated hepatocytes. Furthermore, the influence of different ratios of the number of the cells to the volume of the media was analyzed. Encapsulated hepatocytes cultured with a high amount of medium were characterized by a significantly higher metabolic activity compared to encapsulated hepatocytes cultured with a low level of medium. Interestingly, the cell concentration per mL alginate has no significant influence on the metabolic activity of encapsulated hepatocytes. In conclusion, different optimization strategies are discussed and, finally, the functionality of encapsulated hepatocytes is compared to the standard model of hepatocyte culture, the collagen sandwich.

Near monochromatic X-rays for digital slot-scan mammography: initial findings.

X-ray spectra are composed of a broad bremsspectrum and anode-characteristic emission lines. In mammography typically molybdenum (Mo), rhodium (Rh) or tungsten (W) anodes are used in combination with Mo, Rh or aluminium filters. Only the photons with energies between 17 and 22 keV of the resulting spectrum are suitable for the soft tissue imaging needed for mammography. The aim of this article is to present first results obtained with a monochromator module mounted at the exit of the X-ray tube of a conventional clinical mammography unit. The experimental setup consists of a Siemens Mammomat 300, an X-ray monochromator module and a linear array detector for image acquisition. The technique is similar to the slot-scan technique known from digital mammography. The experimental machine allows to obtain images both with polychromatic and monochromatic X-rays. Initial evaluation of the system was performed by examination of a contrast-detail phantom (CD-MAM-phantom, Nijmegen, The Netherlands). Images done with the new monochromatic technique were compared to images of the phantom done with polychromatic spectra, with film-screen mammography as well as with digital mammography. The new technique with monochromatic slot-scan mammography resulted in correct identification of 93% of the phantom. Digital slot-scan mammography with polychromatic beam resulted in correct identification of 87%, digital full-field mammography in 83% and conventional film-screen mammography in 70% of the phantom. The results suggest that monochromatization has a potential for improving image quality or decreasing dose in X-ray mammography.

Evaluation of a wavelet-based computer-assisted detection system for identifying microcalcifications in digital full-field mammography.

PURPOSE: To evaluate a new wavelet-based computer-assisted detection (CAD) system for detecting and enhancing microcalcifications. MATERIAL AND METHODS: A total of 280 mammograms acquired by full-field digital mammography (Senographe 2000D; G.E. Medical Systems Milwaukee, Wisc., USA) were analyzed with and without a new wavelet-based CAD system for detecting and enhancing microcalcifications. The mammograms comprised roughly equal numbers of cases from each of the BIRADS (Breast Imaging, Reporting and Data System, according to the American College of Roentgenology) categories 1-5. Histologic confirmation was available for all of the 180 cases assigned BIRADS categories 3-5. Four readers interpreted all 280 images for suspicious microcalcifications using a scale of 1-5. The readers alternately assessed 5 images with and 5 without CAD. In a second reading immediately following the first, the readers had to reassess the 280 mammograms. The images that had already been interpreted without CAD were now presented with CAD and vice versa. The images were interpreted as soft copies on a diagnostic mammography workstation (Image Diagnost GmbH, Neufahrn/Munich, Germany). All images interpreted with CAD were presented with enhancement of microcalcifications by wavelet algorithms and prompting of microcalcifications. ROC (receiver operating characteristic) analyses were performed, and image interpretation time with and without CAD was measured. RESULTS: The overall time for interpretation required by all 4 readers together was 483 min with CAD compared to 580 min without CAD. ROC analysis revealed no significant advantage of CAD for the individual readers. Readers 3 (0.811/0.817) and 4 (0.799/0.843) had a slightly improved AUC (area under the curve) with CAD. Readers 1 and 2 had a slightly lower AUC with CAD (0.832 versus 0.861 and 0.818 versus 0.849). CONCLUSION: The CAD system significantly (P<0.05, t test) speeded up image interpretation with respect to the identification of microcalcifications, while the diagnostic quality remained almost identical under the study conditions.

[Preoperative MRT of the breast in invasive lobular carcinoma in comparison with invasive ductal carcinoma]. / Präoperative MRT der Brust beim invasiv-lobulären im Vergleich zum invasiv-duktalen Karzinom.

PURPOSE: To evaluate the role of preoperative MRI of the breast in invasive lobular carcinoma (ILC) compared to invasive ductal carcinoma (IDC). MATERIALS AND METHODS: For one year, all patients transferred by the hospital's gynecologic outpatient service for suspicious findings in routine mammography and/or ultrasound (conventional modalities = CM) underwent preoperative MRI of the breast. Retrospective analysis of the histologic findings identified 17 patients with ILC. These were compared with 30 proven IDC patients, chosen by random. The MRI findings of these 2 patient groups were compared with regard to the detection of additional lesions. The average number of additional lesions detected by MRI was compared for significant differences between both groups using the T-test for paired samples. RESULTS: In the 17 patients with ILC, conventional modalities (CM) identified 21malignant lesions whereas MRI detected a total of 30 lesions. At least one additional lesion was detected by MRI in 7 of the 17 patients with ILC. In the 30 patients with IDC, on the other hand, MRI detected an additional lesion in three instances only. In one patient of the ILC group, MRI identified an additional lesion in the contralateral breast that had escaped detection by CM. No additional contralateral lesion was detected by MRI in any of the IDC patients. Benefit of MRI in ILC-Group: The mean numbers of detected malignant lesions differed significantly between diagnosis by MRI and CM in the ILC group (1.77 carcinomas per patient with MRI versus 1.24 with conventional modalities, T-test, p = 0.0078). Benefit of MRI in IDC-Group: although it was possible to find 1.27 carcinomas vs. 1.17 carcinomas per patient in the IDC-Group, this benefit was not statistical significant (T-test, p = 0.0831). CONCLUSION: Preoperative MRI detects multiple additional lesions compared to the ones already known by CM. The higher incidence of multiple lesions in ILC compared to IDC and the difficult diagnosis of ILC in CM might be the reason for the fact that preoperative MRI is particularly useful in patients with ILC.

[Dose reduction through gridless technique in digital full-field mammography]. / Dosiseinsparung durch rasterlose Technik in der digitalen Vollfeldmammographie.

PURPOSE: To determine the role of the scatter grid in digital full-field mammography with respect to image quality and dose and to compare the experimental results with initial clinical experience. MATERIALS AND METHODS: A phantom consisting of 205 fields that enclose gold dots of different thickness and size (CD-Mam phantom, Medical Department, Nijmegen, Netherlands) was used for digital full-field mammography with the conventional grid module and a special gridless module. Four different breast thicknesses were simulated using Plexiglas as scatter material. First, the phantom was exposed at the parameter and dose settings automatically selected in each experimental setup (with and without grid). Subsequently, the phantom was exposed at the different simulated breast thicknesses using the gridless module in combination with the parameters automatically selected for the grid module. This was followed by a series of phantom mammograms obtained with the experimental setup reversed. The 16 mammograms were evaluated by 3 readers and the results compared considering breast thickness, radiation dose, and quality. The gridless module was used for preoperative labeling in 16 patients for comparison of mammograms obtained with and without a grid. RESULTS: For the same entrance dose used in routine mammography, digital mammography without grid is superior to digital mammography with grid when performed on simulated thin breasts (Plexiglas less than 3 cm), with no difference found when performed on simulated large breasts. The advantages of gridless mammography are more pronounced at a markedly reduced entrance dose (identical parenchymal dose without and with grid using the dose automatically selected for the gridless module). This tendency is confirmed by the initial clinical comparison. CONCLUSION: Gridless digital full-field mammography has the potential to reduce the dose further, in addition to already known mechanisms of dose reduction. However, the gridless system must be adjusted (markedly higher "switch-off dose" at the detector) to achieve an overall dose reduction since gridless mammography is inferior to grid mammography for identical doses at the detector plane.

[Visualization of microcalcifications on mammographies obtained by digital full-field mammography in comparison to conventional film-screen mammography]. / Visualisierung von Mikrokalzifikationen in digitaler Vollfeldmammographie im Vergleich zu konventioneller Film-Folien-Mammographie.

PURPOSE: To evaluate the visualization of microcalcifications on mammographies obtained by full-field digital mammography (FFDM) in comparison to conventional film-screen mammography (FSM). MATERIAL AND METHODS: Forty-seven digital and film-screen mammographies depicting histologically proven lesions (27 benign, 20 malignant) were assessed by 4 readers. The images obtained with the different systems were comparable in terms of positioning. Maximum time interval between film-screen mammography and digital mammography was three months. Using a questionnaire, the readers evaluated the number of microcalcifications and their subjective conspicuity for FFDM (Senographe 2000D, GE Medical Systems, Milwaukee, USA) and FSM. A 7-point scale based on the BIRADS classification was used to characterize the calcifications by means of ROC analysis. RESULTS: No statistically significant differences were seen between the two types of mammography among the readers in assessing the number of microcalcifications. The subjective conspicuity of microcalcifications was found to be significantly better for digital mammographies. The diagnosis assigned by the readers did not show significant differences between the two systems. CONCLUSION: Although the subjective conspicuity of microcalcifications was found to be significantly better on digital mammography compared to film-screen mammography, there was no significant advantage of digital mammography resulting from the higher contrast resolution nor a disadvantage in terms of characterization of microcalcifications resulting from the lower spacial resolution. The advantages of digital mammography (e. g. CAD-systems, archiving, dose reduction) can be used without a loss of diagnostic quality.

Two-step purification of the outer membrane transporter and activator protein ShlB from Escherichia coli using internally His6-tagged constructs.

ShlB from Serratia marcescens was isolated and purified from a porin-deficient Escherichia coli BL21 strain using a combination of detergent extraction, affinity and ion-exchange chromatography. An internal histidine affinity tag was introduced that did not interfere with activity. At each stage of the purification scheme biological activity of the ShlB protein was assessed. Using this scheme, several His(6)-tagged mutants of ShlB were purified to electrophoretic homogeneity.