Development of an analytical method to quantify N-acyl-homoserine lactones in bacterial cultures, river water, and treated wastewater.

N-Acyl-homoserine lactones (AHL) play a major role in the communication of Gram-negative bacteria. They influence processes such as biofilm formation, swarming motility, and bioluminescence in the aquatic environment. A comprehensive analytical method was developed to elucidate the "chemical communication" in pure bacterial cultures as well as in the aquatic environment and engineered environments with biofilms. Due to the high diversity of AHLs and their low concentrations in water, a sensitive and selective LC-ESI-MS/MS method combined with solid-phase extraction was developed for 34 AHLs, optimized and validated to quantify AHLs in bacterial conditioned medium, river water, and treated wastewater. Furthermore, the developed method was optimized in terms of enrichment volume, internal standards, limits of detection, and limits of quantification in several matrices. An unanticipated variety of AHLs was detected in the culture media of Pseudomonas aeruginosa (in total 8 AHLs), Phaeobacter gallaeciensis (in total 6 AHLs), and Methylobacterium mesophilicum (in total 15 AHLs), which to our knowledge have not been described for these bacterial cultures so far. Furthermore, AHLs were detected in river water (in total 5 AHLs) and treated wastewater (in total 3 AHLs). Several detected AHLs were quantified (in total 24) using a standard addition method up to 7.3±1.0 µg/L 3-Oxo-C12-AHL (culture media of P. aeruginosa).

Bromination of Quorum Sensing Molecules: Vanadium Bromoperoxidase and Cerium Dioxide Nanocrystals via Free Active Bromine Transform Bacterial Communication.

The halogenation of quorum sensing molecules (QSMs) is known to be catalyzed by enzymes such as haloperoxidase (HPO) as well as cerium dioxide nanocrystals (NC), which mimic enzymes. Those enzymes and mimics can influence biological processes such as biofilm formation, where bacteria use QSMs for the "chemical" communication between each other and the coordination of surface colonization. However, not much is known about the degradation behavior of a broad spectrum of QSMs, especially for HPO and its mimics. Therefore, in this study, the degradation of three QSMs with different molecule moieties was elucidated. For this purpose, different batch experiments were carried out with HPOs, NCs and free active bromine (FAB). For N-ß-ketocaproyl-homoserine lactone (3-Oxo-C6-AHL), N-cis-tetradec-9Z-enoyl-homoserine lactone (C14:1-AHL) and 2-heptyl-4-quinolone (HHQ) a fast degradation and moiety-specific transformations were observed. The HPO vanadium bromoperoxidase as well as cerium dioxide NCs catalyzed the formation of the same brominated transformation products (TPs). Since the same TPs are formed in batch experiments with FAB it is very likely that FAB is playing a major role in the catalytical reaction mechanism leading to the transformation of QSMs. In this study in total 17 TPs could be identified in different levels of confidence and the catalytic degradation processes for two QS groups (unsaturated AHLs and alkyl quinolones) with cerium dioxide NCs and vanadium bromoperoxidase were expanded.

[Geriatric ultrasound : Prospective evaluation of ultrasound as extended screening in acute geriatric patients]. / Geriatrischer Ultraschall : Prospektive Evaluation der Sonographie als erweitertes Screening bei akutgeriatrischen Patienten.

BACKGROUND: The aim of this study was to evaluate ultrasound as a routinely used procedure and extended physical examination in geriatric patients in acute care. METHODS: Prospective study of 86 patients using ultrasound as a screening examination (abdomen, basal sections of the thorax, thyroid glands) under comparative use of a hand-held ultrasound device (HHUSD) and a high-end ultrasound (HEUS = gold standard). RESULTS: In 20/86 (23.2%) clinically relevant findings with therapeutic consequences were found (pleural effusion, urinary retention, choledocholithiasis metatases, colon tumor). In 22/86 (25.6%) patients, additional questions existed besides the screening indication: tumor search (9.3%), anemia (5.8%), liver value elevation (5.8%), dyspnea (5.8%), splenic pathologies (2.3%), weight loss (1.2%), infectious focus (1.2%), diarrhea (1.2%), intra-abdominal hematoma (1.1%), abdominal aortic aneurysm (1.2%). The most common sonographic findings included: cholecystolithiasis (32.6%); right pleural effusion (31.4%), thyroid nodules (30.2%), renal cysts (27.9%), and fatty liver (26.7%). There were significant differences in sizing between HHUSD and HEUS (kidneys, pancreatic corpus and pancreatic caudal diameters, portal vein, left hepatic vein) without diagnostic relevance. CONCLUSION: The extended screening by ultrasound provided important answers to classical questions in geriatrics (e.g. urinary retention, volume deficiency/pleural effusion) in many cases. The new findings had therapeutic consequences in one fifth of the patients. The HHUSD can be used in screening.

Real-life assessment of standardized contrast-enhanced ultrasound (CEUS) and CEUS algorithms (CEUS LI-RADS®/ESCULAP) in hepatic nodules in cirrhotic patients-a prospective multicenter study.

OBJECTIVES: Hepatocellular carcinoma (HCC) can be diagnosed non-invasively with contrast-enhanced ultrasound (CEUS) in cirrhosis if the characteristic pattern of arterial phase hyperenhancement followed by hypoenhancement is present. Recent studies suggest that diagnosis based on this "hyper-hypo" pattern needs further refinement. This study compares the diagnostic accuracies of standardized CEUS for HCC according to the current guideline definition and following the newly developed CEUS algorithms (CEUS LI-RADS®, ESCULAP) in a prospective multicenter real-life setting. METHODS: Cirrhotic patients with liver lesions on B-mode ultrasound were recruited prospectively from 04/2018 to 04/2019, and clinical and imaging data were collected. The CEUS standard included an additional examination point after 4-6 min in case of no washout after 3 min. The diagnostic accuracies of CEUS following the guidelines ("hyper-hypo" pattern), based on the examiner's subjective interpretation ("CEUS subjective"), and based on the CEUS algorithms ESCULAP and CEUS LI-RADS® were compared. RESULTS: In total, 470 cirrhotic patients were recruited in 43 centers. The final diagnosis was HCC in 378 cases (80.4%) according to the reference standard (histology 77.4%, MRI 16.4%, CT 6.2%). The "hyper-hypo" pattern yielded 74.3% sensitivity and 63% specificity. "CEUS subjective" showed a higher diagnostic accuracy (sensitivity, 91.5%; specificity, 67.4%; positive predictive value, 92%; negative predictive value, 66%). Sensitivity was higher for ESCULAP (95%) and "CEUS subjective" (91.5%) versus CEUS LI-RADS® (65.2%; p < 0.001). Specificity was highest for CEUS LI-RADS® (78.6%; p < 0.001). CONCLUSIONS: CEUS has an excellent diagnostic accuracy for the non-invasive diagnosis of HCC in cirrhosis. CEUS algorithms may be a helpful refinement of the "hyper-hypo" pattern defined by current HCC guidelines. KEY POINTS: • Contrast-enhanced ultrasound (CEUS) has a high diagnostic accuracy for the non-invasive diagnosis of hepatocellular carcinoma (HCC) in cirrhosis. • The CEUS algorithm ESCULAP (Erlanger Synopsis for Contrast-enhanced Ultrasound for Liver lesion Assessment in Patients at risk) showed the highest sensitivity, whereas the CEUS LI-RADS® (Contrast-Enhanced UltraSound Liver Imaging Reporting and Data System) algorithm yielded the highest specificity. • A standardized CEUS examination procedure with an additional examination point in the late phase, after 4-6 min in lesions with no washout after 3 min, is vital.

[Treatment of diabetes mellitus in perioperative medicine-an update]. / Therapie des Diabetes mellitus in der perioperativen Medizin ­ ein Update.

Patients with diabetes who undergo a surgical intervention have an increased risk of metabolic derailment, anesthesiological complications, postoperative infections and cardiovascular events. The treatment of diabetes mellitus is subject to a continuous further development due to pharmaceutical and technical innovations. This article presents the implications of the current concepts of diabetes treatment for perioperative medicine, particularly the changes due to new oral antidiabetic agents and insulin pump treatment. Some of the currently available guidelines are discussed with respect to the care of diabetes patients in childhood and adulthood in connection with an operation. Finally, possible perspectives in the field of monitoring and treatment of diabetes patients are discussed.

Field enhancement in a doubly resonant optical parametric oscillator.

Single-resonant and (signal/idler) double-resonant optical parametric oscillators differ fundamentally on the conversion efficiency back to the pump wave. The nonpresent idler in the single-resonant case allows for signal intracavity enhancement well beyond the pump power level. This paper answers the question, how the phase-matched back conversion in a doubly-resonant system can be overcome to reveal substantial power enhancement, and what parameters it depends on. In a degenerate double-resonant OPO (DROPO) pumped by a thin-disk oscillator, an enhancement up to a factor of four is shown experimentally. Support of a semianalytical theory is presented with exceptionally simple relations between enhancement and intracavity losses. Interestingly, our theory predicts no fundamental limit to the maximal field enhancement or conversion efficiency.

Ultra-broadband EPR spectroscopy in field and frequency domains.

Electron paramagnetic resonance (EPR) is a powerful technique to investigate the electronic and magnetic properties of a wide range of materials. We present the first combined terahertz (THz) field and frequency domain electron paramagnetic resonance (HFEPR/FDMR) spectrometer designed to investigate the electronic structure and magnetic properties of molecular systems, thin films and solid state materials in a very broad frequency range of 85-1100 GHz. In this paper, we show high resolution frequency-field (Zeeman) maps (170-380 GHz by 0-15 T) recorded on two single-molecule magnets, [Mn2(saltmen)2(ReO4)2] and [Mn2(salpn)2(H2O)2](ClO4)2, which give direct access to the field-dependence of the energy level diagram. Furthermore, supression of standing waves in the described system and the sensitivity in field and frequency domain operations is evaluated and discussed.

Room temperature strong coupling in a semiconductor microcavity with embedded AlGaAs quantum wells designed for polariton lasing.

We report a systematic study of the temperature and excitation density behavior of an AlAs/AlGaAs, vertically emitting microcavity with embedded ternary Al0.20Ga0.80As/AlAs quantum wells in the strong coupling regime. Temperature-dependent photoluminescence measurements of the bare quantum wells indicate a crossover from the type-II indirect to the type-I direct transition. The resulting mixing of quantum well and barrier ground states in the conduction band leads to an estimated exciton binding energy systematically exceeding 25 meV. The formation of exciton-polaritons is evidenced in our quantum well microcavity via reflection measurements with Rabi splittings ranging from (13.93 ± 0.15) meV at low temperature (30 K) to (8.58 ± 0.40) meV at room temperature (300 K). Furthermore, the feasibility of polariton laser operation is demonstrated under non-resonant optical excitation conditions at 20 K and emission around 1.835 eV.

[Knowledge, attitude and opinion of patients regarding the new German legislation on advance care planning : Results of a survey in a department of general internal medicine]. / Wissen, Haltung und Meinung von Patienten zum neuen Patientenverfügungsgesetz : Ergebnisse einer Umfrage in einer allgemeininternistischen Abteilung.

BACKGROUND: In September 2009 a new legislation for advance care planning was introduced in Germany with the important characteristics of bindingness and unlimited validity for individual directives. Knowledge regarding this act and the attitude towards its characteristics among patients is unclear. AIM OF THIS STUDY: Analysis of knowledge, attitude and opinion of patients in a general internal medical department regarding advance care planning in general and the recent German legislation. METHODS: A total of 200 consecutive patients in an internal medicine ward were interviewed with the help of a questionnaire regarding their attitude to and knowledge on advance care planning in general and the current legislation. RESULTS: Approximately 40 % of the patients had issued some form of directive (either advance care directive or health care proxy) and only 7.5 % were advised by their physicians to make an advance directive. Patients with no directive were not willing to deal with dying and death, were not well-informed about directives or assumed that relatives or physicians would make an appropriate decision. Characteristics of the new legislation were controversially assessed; only 21 % of the patients wished to have a literal implementation of their directive. Regarding the content of an advance directive, more than 80 % of the patients voted for pain control in the palliative setting. CONCLUSION: The proportion of patients with a directive regarding advance care planning is only slowly increasing. Many patients are not well-informed, do not want to deal with dying or would like to delegate decisions to relatives and physicians. The present characteristics of the German legislation are controversially assessed and often do not represent the wishes of the patients.

Percutaneous sclerotherapy of liver and renal cysts, comments on the EFSUMB guidelines.

Cystic lesions in the liver and kidneys are common incidental findings. They are generally benign and require no treatment. They can appear sporadically or as part of a syndrome, and are characterised by their anechoic structure and posterior enhancement in ultrasound imaging. Increased size, haemorrhage or infection of a cyst can lead to development of symptoms. Along with surgical options and laparoscopic cyst fenestration, ultrasound-guided sclerotherapy of symptomatic cysts represents an effective and safe minimally invasive treatment option.

[Ultrasound artifacts and their diagnostic significance in internal medicine and gastroenterology - part 2: color and spectral Doppler artifacts]. / Artefakte in der Sonografie und ihre Bedeutung für die internistische und gastroenterologische Diagnostik - Teil 2: Artefakte im Farb- und Spektraldoppler.

Artifacts in ultrasonographic diagnostics are a result of the physical properties of the ultrasound waves and are caused by interaction of the ultrasound waves with biological structures and tissues of the body and with foreign materials. On the one hand, they may be diagnostically helpful. On the other hand, they may be distracting and may lead to misdiagnosis. Profound knowledge of the causes, avoidance, and interpretation of artifacts is a necessary precondition for correct clinical appraisal of ultrasound images. Part 1 of this review commented on the physics of artifacts and described the most important B-mode artifacts. Part 2 focuses on the clinically relevant artifacts in Doppler and color-coded duplex sonography. Problems and pitfalls of interpretation arising from artifacts, as well as the diagnostic use of Doppler and colour-coded duplex sonography, are discussed.

[Ultrasound artifacts and their diagnostic significance in internal medicine and gastroenterology - Part 1: B-mode artifacts]. / Artefakte in der Sonografie und ihre Bedeutung für die internistische und gastroenterologische Diagnostik - Teil 1: B-Mode-Artefakte.

Artifacts in ultrasonographic diagnostics are a result of the physical properties of the ultrasound waves and are caused by interaction of the ultrasound waves with biological structures and tissues and with foreign bodies. On the one hand, they may be distracting and may lead to misdiagnosis. On the other hand, they may be diagnostically helpful. Ultrasound imaging suffers from artifacts, because in reality, parameters assumed to be constant values, such as sound speed, sound rectilinear propagation, attenuation, etc., are often different from the actual parameters. Moreover, inadequate device settings may cause artifacts. Profound knowledge of the causes, avoidance, and interpretation of artifacts is a necessary precondition for correct clinical appraisal of ultrasound images. Part 1 of this review comments on the physics of artifacts and describes the most important B-mode artifacts. Pitfalls, as well as diagnostic chances resulting from B-mode artifacts, are discussed.

Microwave ablation of hepatic tumors with a third generation system: loco­regional efficacy in a prospective cohort study with intermediate term follow-up.

PURPOSE: To evaluate the safety and intermediate-term efficacy of percutaneous microwave ablation (MWA) in primary and secondary liver tumors using a third generation MWA device, under ultrasound guidance. PATIENTS AND METHODS: Sixty-two patients (median age 74 years, 73 % males) with 69 liver tumors were enrolled in this prospective observational study. Forty-seven patients (76 %) had hepatocellular carcinoma (HCC) and 15 (24 %) metastases. Median follow-up was 3.6 years. RESULTS: Median tumor diameter at contrast enhanced computed tomography was 23 mm (I-III quartiles, 18 - 31 mm). All procedures were performed percutaneously using a 2.45 GHz generator. Median ablation time was 10 minutes (I-III quartiles, 10 - 14 minutes). A single percutaneous antenna insertion was performed for 56/69 (81 %) of the tumors. Technical success was obtained in all tumors. Primary efficacy at 24 hours was achieved in 68/69 (99 %) tumors. The overall one-year cumulative local tumor progression rate was 15.1 % (95 % CI, 7.7 - 24.8 %) with no significant difference between HCC and metastases (p = 0.26). There was one procedure-related mortality (1.6 %) and one major bleeding (1.6 %). CONCLUSION: Microwave ablation is a valid option for thermal ablation of HCC and liver metastases with comparable complication rate to other local ablative procedures.

Duplex sonography of the mesenteric vessels--a critical evaluation of inter-observer variability.

INTRODUCTION: The number of publications concerning mesenteric Doppler sonography (mesDS) is immense and does not correlate with the frequency of its use in clinical practice. This is astonishing since it provides real time blood flow (perfusion) information without side effects. Despite uncontrollable parameters like the technical limitations in some situations the optimization of (possibly) controllable parameters like standardization, production of normal values and reduction of the investigator variability by evaluating stable parameters could change the situation. PATIENTS AND METHODS: 10 investigators experienced in abdominal sonography ("DEGUM-Seminarleiter") performed mesenteric Doppler sonography in 5 healthy subjects with 5 different machines. RESULTS: The portal vein at the confluence and the common hepatic artery provide a significant portion of investigations with intromission angles of more than 60°. Values of diameter, resistance index and pulsatility index of the celiac trunc could be obtained with inter-observer variability values below 25 %. The proper and the common hepatic artery show no differences in inter-observer variability values, whereas the intrahepatic measure point of the portal vein showed a higher reproducibility. DISCUSSION: We define frame conditions for future mesenteric Doppler studies: the portal vein should be investigated at the intrahepatic measure point. Pathophysiological studies should refrain from velocity parameters except in the case of larger vessels running in a straight course towards the probe.

Ultrasound assessment of schistosomiasis.

In 2000, the World Health Organization (WHO) issued an ultrasound field protocol for assessing the morbidity due to Schistosoma (S.) haematobium and S. mansoni. The experience with this classification has recently been reviewed systematically. The WHO protocol was well accepted worldwide. Here we review the use of ultrasound to assess the morbidity due to schistosomiasis with emphasis on easy, quick, and reproducible ways that can be used in the field. Findings obtained with high-end ultrasound scanners in the hospital setting that might eventually have applications in the field are also described.

Clinical value of imaging for lymph nodes evaluation with particular emphasis on ultrasonography.

Enlarged or irregular lymph nodes (LNs) are clinical and imaging findings in a large variety of malignant and non-malignant diseases. A comprehensive diagnostic work up is usually necessary in order to differentiate the benign or the malignant nature of the altered LNs. The diagnosis has to be made using all clinical information and, if necessary, assessed LNs need to be biopsied and further, histologically or microbiologically characterized. However, imaging techniques, and particularly ultrasonography (US), are essential on the way to the final diagnosis, from initial detection and characterization to follow-up of biopsy guidance. Computed-tomography (CT) and/or magnetic resonance imaging (MRI) are of great value for oncological diseases staging and treatment monitoring. Imaging techniques are helpful in distinguishing between benign and malignant LNs disease as well as between LNs metastases and lymphoma in most cases. Furthermore, imaging can define the extent and distribution of malignant diseases. It may assist, through the use of particular techniques such as elastography, to identify the most suspicious LN to be biopsied and to guide targeted biopsies from the most suspicious areas. It also serves as the main tool for the evaluation of treatment response in malignant diseases. The quality of LNs imaging has remarkably improved in recent years. New methods, such as contrast-enhanced ultrasonography (CEUS), elastography, positron emission tomography (PET)/PET-CT, as well as diffusion weighted imaging (DWI) in MRI, have already led to substantial changes in clinical practice. This review describes the most recent imaging techniques for LNs assessment, and their particular clinical value, with a special emphasis on the role of US techniques. Strengths and weaknesses of different imaging tools are discussed comprehensively, highlighting the importance of a corroborative attitude for successful management of each particular case.

EFSUMB Guidelines on Interventional Ultrasound (INVUS), Part VI - Ultrasound-Guided Vascular Interventions.

The sixth part of the Guidelines on Interventional Ultrasound produced under the auspices of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) assesses the evidence for ultrasound guidance and assistance in vascular interventions. Based on convincing data, real-time sonographic guidance for central venous access is strongly recommended as a key safety measure. Systematic analysis of scientific literature shows that in difficult situations and special circumstances US guidance may also improve the efficacy and safety of peripheral venous and arterial access and endovascular interventions. Moreover, the recommendations of this guideline endorse the use of ultrasound to detect complications of vascular access and US-guided interventional treatment of arterial pseudoaneurysms.

Evaluation of Strain Elastography for Differentiation of Thyroid Nodules: Results of a Prospective DEGUM Multicenter Study.

PURPOSE: Many patients with thyroid nodules are presently referred to surgery for not only therapeutic but also diagnostic purposes. The aim of noninvasive diagnostic methods is to optimize the selection of patients for surgery. Strain elastography (SE) enables the ultrasound-based determination of tissue elasticity. The aim of the present study was to evaluate the value of SE for the differentiation of thyroid nodules in a prospective multicenter study. MATERIALS AND METHODS: The study was registered at clinicaltrials.gov and was approved by the local ethics committees of all participating centers. All patients received an ultrasound (US) of the thyroid gland including color Doppler US. In addition, all nodules were evaluated by SE (Hitachi Medical Systems) using qualitative image interpretation of color distribution (SE-ES), strain value and strain ratio. RESULTS: Overall, 602 patients with 657 thyroid nodules (567 benign, 90 malignant) from 7 centers were included in the final analysis. The sensitivity, specificity, NPV, PPV, +LR were 21 %, 73 %, 86 %, 11 %, 0.8, respectively, for color Doppler US; 69 %, 75 %, 94 %, 30 %, 2.9, respectively, for SE-ES; 56 %, 81 %, 92 %, 32 %, 2.9, respectively, for SE-strain value; and 58 %, 78 %, 92 %, 30 %, 2.6, respectively, for SE-strain ratio. The diagnostic accuracy was 71 % for both strain value and strain ratio of nodules. CONCLUSION: SE as an additional ultrasound tool improves the value of ultrasound for the work-up of thyroid nodules. It might reduce diagnostic surgery of thyroid nodules in the future.