Cooper pair splitting in parallel quantum dot Josephson junctions.

Devices to generate on-demand non-local spin entangled electron pairs have potential application as solid-state analogues of the entangled photon sources used in quantum optics. Recently, Andreev entanglers that use two quantum dots as filters to adiabatically split and separate the quasi-particles of Cooper pairs have shown efficient splitting through measurements of the transport charge but the spin entanglement has not been directly confirmed. Here we report measurements on parallel quantum dot Josephson junction devices allowing a Josephson current to flow due to the adiabatic splitting and recombination of the Cooper pair between the dots. The evidence for this non-local transport is confirmed through study of the non-dissipative supercurrent while tuning independently the dots with local electrical gates. As the Josephson current arises only from processes that maintain the coherence, we can confirm that a current flows from the spatially separated entangled pair.

The role of multi-slice spiral CT angiography in patient management after endovascular therapy.

OBJECTIVES: To bring out the role of multi-slice spiral CT angiography (MS-CTA) in patient management after endovascular therapy of subclavian artery stenosis. METHODS: Twenty-one consecutive patients with clinically suspected restenosis after endovascular treatment of subclavian artery stenosis or occlusion were included in the study. Eleven patients had been treated with percutaneous transluminal angioplasty (PTA) alone and 10 with PTA and stenting. The mean follow-up period after PTA or stenting was 57 (+/-27 SD) months. CTA was performed using a bolus-triggered high-resolution protocol with biphasic intravenous contrast medium injection. Axial images and curved planar reformations (CPRs) were rated by three readers with regard to patency of supra-aortic vessels. Imaging findings were correlated with a standardized clinical assessment. RESULTS: All examinations were of diagnostic quality. Of 21 referred patients, 7 had significant reobstruction of the treated subclavian artery. Six of the 7 patients with significant restenosis on CTA were treated conservatively (antiplatelet agents), despite 2 of them being symptomatic on the standardized clinical assessment, which showed a sensitivity and specificity of 86% in predicting stenosis. One patient was treated with PTA and stent deployment because of strong subjective suffering. CONCLUSION: MS-CTA is useful for exclusion or quantification of clinically suspected restenosis in carefully selected patients after endovascular therapy where ultrasound is inconclusive and/or contrast-enhanced magnetic resonance angiography is contraindicated.

Quantification of axial alignment of the lower extremity on conventional and digital total leg radiographs.

The purpose was to assess axial alignment of the lower limb using mechanical axis measurements on conventional and digital radiographs. Total-leg radiographs of 24 patients, 8 male and 16 female, with a mean age of 68.6+/-10.2 years, were performed in a standardized anterior-posterior projection and standing position using a conventional and digital phosphor storage film screen radiography system. Knee joint angulation was assessed by measuring the angle between a line drawn from the center of the femoral head to the middle of the femoral condyles and a line drawn from the middle of the tibial condyles to the midpoint of the malleolus. On conventional leg radiographs, line drawing and angle measurement were performed manually with a transparent goniometer. Angle measurement on digital leg radiographs was performed on a PACS workstation using computer-assisted measurement software (IMPAX, AGFA-GEVAERT, Belgium). Evaluation time for both measurements was recorded. We diagnosed 14 varus and 10 valgus angulations of the knee joint. The mean individual difference between axis deviation of conventional digital leg radiographs was 0.93+0.6 degrees (min 0 degrees, max 2 degrees), the mean difference in varus angulation was 1.13+/-0.45 degrees (min 0.3 degrees, max 2 degrees), and the mean difference in valgus angulation was 0.65+/-0.71 degrees (min 0 degrees, max 2 degrees). Angle measurements on conventional and digital radiographs did not show any statistically significant difference. Mean time exposure was 4.9 min/patient for manual and 1.08 min/patient for computer-assisted angle measurement (P<0.001). Computer-assisted angle measurement on digital total-leg radiographs represents a reliable method with no significant angle differences compared to conventional radiographic systems and offers a significantly lower evaluation time.

[Shoulder instability]. / Schultergelenkinstabilität.

Shoulder instability is a common clinical feature leading to recurrent pain and limited range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation. Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex. The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions. The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging.

[Digital thorax radiography: flat-panel detector or storage phosphor plates]. / Digitale Thoraxradiographie: Flat-panel-Detektor oder Speicherfolie?

Flat panel detectors are characterized by improved handling and increased dose efficiency. This allows for increasing of work flow efficiency and for reducing the exposure dose by about 50% compared to current systems with a sensitivity of 400. Whether the increased dose efficiency should be used to reduce acquisition dose or to increase image quality in the chest, will be shown by further clinical experience and will be also determined by the subjective preference of the radiologists. The decreased level of image noise opens new perspectives for image processing that way that elaborated multifrequency processing allows for optimizing the display of very small and low contrast structures that was so far limited by overlying image noise. Specialized applications of dual energy subtraction and temporal subtraction will also profit by the new detector technology and will be further driven forward in context with applications such as computed assisted diagnosis even though this is currently not yet broadly applied. Storage phosphor radiography still represents an important alternative technique based on its larger flexibility with respect to equipment configuration, its broader application options in intensive care and emergency radiology and due to economic reasons. These facts are further underlined by the fact that image quality also in storage phosphor radiography could be constantly increased by improving detector technology and image processing and consequently has a high standard.

Predictors of long-term results after treatment of iliac artery obliteration by transluminal angioplasty and stent deployment.

PURPOSE: To investigate initial and long-term success rate after percutaneous treatment of iliac artery occlusion with angioplasty and stent deployment. To investigate the influence of vascular comorbidity, lesion length, stent placement and lesion coverage as possible predictors of outcome. METHODS: Between January 1994 and December 1999, 80 iliac recanalizations were performed on 78 patients, median age 61.1 +/- 11.5 (SD) years. All patients were followed up by clinical examinations, duplex ultrasound and intravenous digital subtraction angiography. Mean follow-up time was 2.0 +/- 1.53 (SD) years. Multivariate Cox regression analysis was used to determine the influence of cofactors on patency. RESULTS: One, 2 and 4 years after recanalization, primary patency was 78.1%, 74.5% and 64.0%; secondary patency was 88.8%, 88.8% and 77.9%, respectively. Patients with shorter occlusions, complete lesion coverage and patent ipsilateral femoral arteries had significantly longer patency rates. Complications included inguinal hematoma (n=1), technical failure (n=3) aortic dissection (n=1), embolic occlusions (n=7), gluteal claudication (n=1) and genital necrosis after subsequent urethral surgery in one patient with contralateral occlusion and ipsilateral overstenting of the internal iliac artery with subsequent stenosis. Complications were of permanent clinical significance in seven of 78 (9%) of the patients. In 17 (22%) cases, percutaneous reintervention was performed with angioplasty in the stent (n=16) or deployment of a new stent (n=1). CONCLUSION: Endoluminal stent placement has its place in an interdisciplinary therapeutic approach as a viable therapeutic alternative to major transabdominal bypass surgery and can be performed with comparable complication rates. Patients with short occlusions, patent femoral arteries, and stents covering the entire occlusion have significant longer patency.

Endovascular treatment of aortic type B dissection and penetrating ulcer using commercially available stent-grafts.

OBJECTIVE: The purpose of our study was to investigate the clinical experience and efficiency of translumenl endovascular stent-graft insertion using commercially available vascular endoprotheses. We studied seven patients with descending aortic dissection (type B) and four patients with penetrating aortic ulcer over a median follow-up period of 254 days during the years 1997-2000, using cross-sectional CT to evaluate the extent of the dissection, the distance between the entry tear and the left subclavian artery, and the diameter of the true lumen and the false lumen. CONCLUSION: Endovascular treatment of acute and chronic aortic type B dissections and penetrating ulcer is a minimally invasive method with a low complication rate that could be considered a feasible alternative to surgical repair. Depending on the length of the dissection, we recommend the placement of two overlapping stent-grafts in the thoracic aorta to stabilize the affected thoracic aorta over a longer distance. This might provide a reliable sealing of the entry tear and should prevent further communication between the true lumen and the false lumen.

[Radiologic quantification of joint changes. A methodological overview]. / Radiologische Quantifizierung von Gelenkveränderungen. Ein methodischer Uberblick.

Osteoarthritis as well as rheumatoid arthritis lead to chronical progressive destruction of diseased joints. As aggressive new treatments need to be evaluated, plenty of (semi-) quantitative methods for the radiological joint evaluation had been developed. They lack sufficient reproducibility due to their low objectivity. Modern approaches of computer-assisted radiological quantification should increase the reproducibility and efficiency of radiological scoring. Automatically calculated, computer-assisted measurements of joint space, cartilage- and synovial volume, periarticular assessment of bone mineral density and quantitative analysis of the subchondral plate will have major impact on the radiological routine of the future.

Screening for prostate cancer: is ultrasound the answer?

The high incidence and subsequent mortality from prostate cancer in progressively older US males is a serious health concern. Prognosis is related to extent of spread of the disease at the time of diagnosis and to pathologic grading of the tumor cells. The argument for early detection is somewhat clouded by a high incidence of latent prostate cancer related to increasing age, which may or may not progress to clinical disease. Recent applications of ultrasound technology have greatly improved our ability to image the prostate gland and raised the possibility of using ultrasound to screen for prostate cancer. The conclusions of this investigation are that ultrasound should not yet replace annual digital rectal examination as the primary screening tool, but ultrasound is a useful diagnostic adjunct. This recommendation may change with further application of the technology and as more information is gathered.

[Development of a numerically additive combined vaccine against tetanus and smallpox]. / Entwicklung einer numerisch-additiven Kombinationsvaccine gegen Tetanus und Pocken.

Mandatory vaccination against smallpox was abolished on the account of smallpox-eradication proclaimed by the WHO and the postvaccinal complications detected after smallpox vaccination. At the same time vaccine banks with the vaccinia virus strain "Elstree" were organized. Should mass vaccinations with this vaccinia virus strain be carried out in a case of emergency, severe postvaccinal diseases and complications can arise in overaged and immunosuppressed vaccinees after primovaccination. Therefore attenuated vaccinia virus strains should be used for vaccine banks, which cannot be activated, or increase in virulence in impaired vaccinees after primovaccination. For these individuals the vaccinia virus strain "MVA", among other attenuated vaccinia strains, is recommended. The MVA virus strain can be applied parenterally without complications. From the scientific and field-relevant point of view it was tried to combine the vaccinia virus strain "MVA" with tetanus toxoid and to develop a combination vaccine "tetanus-smallpox". In immunization experiments using mice, piglets and monkeys, safety and efficacy of the vaccine were investigated. Efficacy was demonstrated by means of postvaccinal antibody determination and by the mouse protection test. Tetanus antitoxin was measured by ELISA and indirect hemagglutination test, antibody levels to vaccinia virus were investigated employing the neutralization test and hemagglutination inhibition test. No significant differences in potency could be demonstrated between the combination vaccine and the corresponding monovalent vaccines in mice, piglets and monkeys. The combination vaccine consisted of 12 Lf tetanus toxoid and 10 TCID50 vaccinia virus "MVA" preserved with gelatine and glucosamine. The double intramuscular immunization of monkeys stimulated average tetanus antitoxin titers of 1:310 and average vaccinia virus titers of 1:195 2 weeks p. revacc. Similar results were obtained in mice and piglets. Side reactions were not observed in mice and piglets. Except for occasional local reactions of short duration at the injection site of the monkeys, similarly no adverse reactions were observed after intramuscular vaccination with the combination vaccine.

Heart transplantation. Four years' experience with conventional immunosuppression.

This article describes four years' experience with heart transplantation using conventional immunosuppression. Twenty of 32 patients are alive. The one-year survival rates were 75% (1979), 67% (1980), and 75% (1981). Actuarial survival rates for operative survivors were 70% at one year, 60% at two years, and 51% at three years. Patients in the 50- to 55-year age group have survived as well as younger recipients. Rejection resulted in six deaths, infection in three, donor heart failure in two, and multiple organ failure in one. There were 1.5 acute rejections per patient and one infection per patient in the first three posttransplant months. Postoperative hospital stay averaged 62 days and cost a total of $58,351.

[Radioprotective effectiveness of the paramunity inducer "pind-avi": investigation using the model "protective tetanic vaccination in mice" after exposure to X-rays (author's transl)]. / Untersuchungen über eine Strahlenschutzwirkung des Paramunitätsinducers "Pind-Avi" am Modell "Tetanus-Schutzimpfung-Maus" nach Röntgenbestrahlung.

The model "protective tetanic vaccination in mice" was used in order to try whether the paramunity inducer Pind-Avi may diminish or suspend radiation-induced immunosuppression. The radioprotective effect was ascertained from the different results of immunization in mice exposed to radiation after pretreatment with either Pind-Avi or placebo. The dose delivered amounted to 300 R. Tetanus toxoid was used for immunization. Effectiveness of the tetanic vaccination was analysed by means of load tests with 10 LD50 tetanus toxin, and of antibody determination with passive hemagglutination. Evidence was shown of significant radiation protection following subcutaneous application of Pind-Avi once a day during three days before of after exposure. Efficiency in mice treated with Pind-Avi amounted to 75% (pre-irradiation treatment) and to 43% (postirradiation treatment), whereas the efficiency in controls was zero in all cases. Thus, it was possible with Pind-Avi to suspend radiation-induced immunosuppression within a period of 3 days before or after radiation exposure, not only by means of prophylactic but also by therapeutic administration.

[Nonspecific prophylaxis and therapy of Pseudomonas aeruginosa wound-infections with paramunization using a mouse-model (author's transl)]. / Erregerunspezifische Prophylaxe und Therapie von Pseudomonas aeruginosa-Wundinfektionen mittels Paramunisierung im Mäusemodell.

The effectiveness of paramunization as a antigen nonspecific method to activate mechanisms against wound-infections due to Pseudomonas aeruginosa was studied using a model of direct infection of mice with a "mice-pathogenic" Ps. aeruginosa strain on artificially set wounds. Active paramunization by means of a biological inducer "PIND-AVI" (M-HP 438) significantly reduced the mortality rate between treated and placebo animals. The best results were obtained by parenteral prophylactic application. A four times repeated injection of PIND-AVI before the wound-infection reduced the mortality rate from 80% (placebo animals) to 26.6%. Almost equally good results were obtained by clinically useful therapeutic application of the preparation. A four times repeated treatment of the mice after wound infection lead to a decrease of mortality rates from 86.6% to 36.6%. The paramunization inducer PIND-AVI caused no side effect in any of the experiments. The mode of inducer action in Pseudomonas aeruginosa wound infections appears to be complex. Increased phagocytosis by nonspecific opsonisation, increased macrophage activity and concurrent stimulation of the lymphopoetic system could possible occur. On the other hand the nonspecific action of mediators could also play a role due to the inducer stimulated T-cells and cellular antigens of Pseudomonas aeruginosa. However both mechanisms in cooperation with specific and nonspecific humoral factors are probably interacting together. To what extent a simultaneous synthesis resp. release of endogeneous interferon plays a role is not known.