An electroluminescent and tunable cavity-enhanced carbon-nanotube-emitter in the telecom band

Emerging photonic information processing systems require chip-level integration of controllable nanoscale light sources at telecommunication wavelengths. Currently, substantial challenges remain in the dynamic control of the sources, the low-loss integration into a photonic environment, and in the site-selective placement at desired positions on a chip. Here, we overcome these challenges using heterogeneous integration of electroluminescent (EL), semiconducting carbon nanotubes (sCNTs) into hybrid two dimensional - three dimensional (2D-3D) photonic circuits. We demonstrate enhanced spectral line shaping of the EL sCNT emission. By back-gating the sCNT-nanoemitter we achieve full electrical dynamic control of the EL sCNT emission with high on-off ratio and strong enhancement in the telecommunication band. Using nanographene as a low-loss material to electrically contact sCNT emitters directly within a photonic crystal cavity enables highly efficient EL coupling without compromising the optical quality of the cavity. Our versatile approach paves the way for controllable integrated photonic circuits.

Low-Divergence hBN Single-Photon Source with a 3D-Printed Low-Fluorescence Elliptical Polymer Microlens

Efficiently collecting light from single-photon emitters is crucial for photonic quantum technologies. Here, we develop and use an ultralow fluorescence photopolymer to three-dimensionally print micrometer-sized elliptical lenses on individual precharacterized single-photon emitters in hexagonal boron nitride (hBN) nanocrystals, operating in the visible regime. The elliptical lens design beams the light highly efficiently into the far field, rendering bulky objective lenses obsolete. Using back focal plane imaging, we confirm that the emission is collimated to a narrow low-divergence beam with a half width at half-maximum of 2.2°. Using photon correlation measurements, we demonstrate that the single-photon character remains undisturbed by the polymer lens. The strongly directed emission and increased collection efficiency is highly beneficial for quantum optical experiments. Furthermore, our approach paves the way for a highly parallel fiber-based detection of single photons from hBN nanocrystals.

Ultrafast quantum key distribution using fully parallelized quantum channels

The field of quantum information processing offers secure communication protected by the laws of quantum mechanics and is on the verge of finding wider application for the information transfer of sensitive data. To improve cost-efficiency, extensive research is being carried out on the various components required for high data throughput using quantum key distribution (QKD). Aiming for an application-oriented solution, we report the realization of a multichannel QKD system for plug-and-play high-bandwidth secure communication at telecom wavelengths. We designed a rack-sized multichannel superconducting nanowire single photon detector (SNSPD) system, as well as a highly parallelized time-correlated single photon counting (TCSPC) unit. Our system is linked to an FPGA-controlled QKD evaluation setup for continuous operation, allowing us to achieve high secret key rates using a coherent-one-way protocol.

Scaling waveguide-integrated superconducting nanowire single-photon detector solutions to large numbers of independent optical channels

Superconducting nanowire single-photon detectors are an enabling technology for modern quantum information science and are gaining attractiveness for the most demanding photon counting tasks in other fields. Embedding such detectors in photonic integrated circuits enables additional counting capabilities through nanophotonic functionalization. Here, we show how a scalable number of waveguide-integrated superconducting nanowire single-photon detectors can be interfaced with independent fiber optic channels on the same chip. Our plug-and-play detector package is hosted inside a compact and portable closed-cycle cryostat providing cryogenic signal amplification for up to 64 channels. We demonstrate state-of-the-art multi-channel photon counting performance with average system detection efficiency of (40.5 ± 9.4)% and dark count rate of (123 ± 34) Hz for 32 individually addressable detectors at minimal noise-equivalent power of (5.1 ± 1.2) · 10^-18 W/Hz. Our detectors achieve timing jitter as low as 26 ps, which increases to (114 ± 17) ps for high-speed multi-channel operation using dedicated time-correlated single photon counting electronics. Our multi-channel single photon receiver offers exciting measurement capabilities for future quantum communication, remote sensing, and imaging applications.

Broadband Spectrometer with Single-Photon Sensitivity Exploiting Tailored Disorder

Harnessing tailored disorder for broadband light scattering enables high-resolution signal analysis in nanophotonic spectrometers with a small device footprint. Multiple scattering events in the disordered medium enhance the effective path length which leads to increased resolution. Here we demonstrate an on-chip random spectrometer cointegrated with superconducting single-photon detectors suitable for photon-scarce environments. We combine an efficient broadband fiber-to-chip coupling approach with a random scattering area and broadband transparent silicon nitride waveguides to operate the spectrometer in a diffusive regime. Superconducting nanowire single-photon detectors at each output waveguide are used to perform spectral-to-spatial mapping via the transmission matrix at the system, allowing us to reconstruct a given probe signal. We show operation over a wide spectral range with sensitivity down to powers of -111.5 dBm in the telecom band.

Broadband out-of-plane coupling at visible wavelengths

Photonic integrated circuits require efficient interfaces to fiber optic components for applications in optical communication, computing, and sensing. Current optical interconnects rely on edge or grating couplers with limitations in terms of alignment tolerances, efficiency, and bandwidth, respectively. Here, we present a scalable coupling concept that allows fiber-to-chip coupling to the fundamental transverse electric and transverse magnetic modes based on three-dimensional nanostructures exploiting total internal reflection. We demonstrate close to octave-spanning highly efficient coupling to nanophotonic waveguides in the visible wavelength range. Our coupling scheme can be adjusted for other wavelength regimes and fiber mode-field diameters.

[Future trend medical apps. From the apps store directly into medical practice?]

In day to day medical care, patients, nursing staff and doctors currently face a bewildering and rapidly growing number of health-related apps running on various "smart" devices and there are also uncountable possibilities for the use of such technology. Concerning regulation, a risk-based approach is applied for development and use (including safety and security considerations) of medical and health-related apps. Considering safety-related issues as well as organizational matters, this is a sensible approach but requires honest self-assessment as well as a high degree of responsibility, networking and good quality management by all those involved. This cannot be taken for granted. Apart from regulatory aspects it is important to not only consider what is reasonable, helpful or profitable. Quality aspects, safety matters, data protection and privacy as well as liability issues must also be considered but are often not adequately respected. If software quality is compromised, this endangers patient safety as well as data protection, privacy and data integrity. This can for example result in unwanted advertising or unauthorized access to the stored data by third parties; therefore, local, regional and international regulatory measures need to be applied in order to ensure safe use of medical apps in all possible areas, including the operating room (OR) with its highly specialized demands. Lawmakers need to include impulses from all stakeholders in their considerations and this should include input from existing private initiatives that already deal with the use and evaluation of apps in a medical context. Of course, this process needs to respect pre-existing national, European as well as international (harmonized) standards.

Effect of PEEP on regional ventilation during laparoscopic surgery monitored by electrical impedance tomography

BACKGROUND

Anesthesia per se and pneumoperitoneum during laparoscopic surgery lead to atelectasis and impairment of oxygenation. We hypothesized that a ventilation with positive end-expiratory pressure (PEEP) during general anesthesia and laparoscopic surgery leads to a more homogeneous ventilation distribution as determined by electrical impedance tomography (EIT). Furthermore, we supposed that PEEP ventilation in lung-healthy patients would improve the parameters of oxygenation and respiratory compliance.

METHODS

Thirty-two patients scheduled to undergo laparoscopic cholecystectomy were randomly assigned to be ventilated with ZEEP (0 cmH(2)O) or with PEEP (10 cmH(2)O) and a subsequent recruitment maneuver. Differences in regional ventilation were analyzed by the EIT-based center-of-ventilation index (COV), which quantifies the distribution of ventilation and indicates ventilation shifts.

RESULTS

Higher amount of ventilation was examined in the dorsal parts of the lungs in the PEEP group. Throughout the application of PEEP, a lower shift of ventilation was found, whereas after the induction of anesthesia, a remarkable ventral shift of ventilation in ZEEP-ventilated patients (COV: ZEEP, 40.6 ± 2.4%; PEEP, 46.5 ± 3.5%; P<0.001) was observed. Compared with the PEEP group, ZEEP caused a ventral misalignment of ventilation during pneumoperitoneum (COV: ZEEP, 41.6 ± 2.4%; PEEP, 44 ± 2.7%; P=0.013). Throughout the study, there were significant differences in the parameters of oxygenation and respiratory compliance with improved values in PEEP-ventilated patients.

CONCLUSION

The effect of anesthesia, pneumoperitoneum, and different PEEP levels can be evaluated by EIT-based COV monitoring. An initial recruitment maneuver and a PEEP of 10 cmH(2)O preserved homogeneous regional ventilation during laparoscopic surgery in most, but not all, patients and improved oxygenation and respiratory compliance.

Blood gas partition coefficient and pulmonary extraction ratio for propofol in goats and pigs

The interpretation of continuously measured propofol concentration in respiratory gas demands knowledge about the blood gas partition coefficient and pulmonary extraction ratio for propofol. In the present investigation we compared both variables for propofol between goats and pigs during a propofol anaesthesia. In ten goats and ten pigs, expired alveolar gas and arterial and mixed venous blood samples were simultaneously drawn during total intravenous anaesthesia with propofol. The blood gas partition coefficient and pulmonary extraction ratio were calculated for both species. Non-parametric methods were used for statistical inference. The blood gas partition coefficient ranged between 7000 and 646,000 for goats and between 17,000 and 267,000 for pigs. The pulmonary extraction ratio ranged between 32.9% and 98.1% for goats and was higher for pigs, which ranged between -106.0% and 39.0%. The blood gas partition coefficient for propofol exceeded those for other known anaesthetic compounds so that it takes longer to develop a steady-state. The different pulmonary extraction rates in two species suggest that there are different ways to distribute propofol during the lung passage on its way from the blood to breathing gas. This species-specific difference has to be considered for methods using the alveolar gas for monitoring the propofol concentration in plasma.

Die Anwendung der Spiral-Larynxmaske zur Adenotomie bei Kindern - Ein retrospektiver Vergleich zur Intubationsnarkose

BACKGROUND

While adenoidectomy in childhood is a standard procedure, different alternatives of airway and anaesthesiologic management are discussed. Therefore we investigated retrospectively paediatric anaesthesias with laryngeal mask (LMA) or endotracheal intubation (ITN) during adenoidectomies in our department of otorhinolaryngology.

METHODS

A retrospective analysis of 385 anaesthesia records of the last three years was performed. Variables were age and weight of the children, anaesthetics, surgical procedures, size of LMA, recovery time, anaesthesiological complications as well as the incidence of abandoning the laryngeal mask in favour of a tracheal intubation.

RESULTS

Recovery time was significantly reduced (3.63 min) in LMA group compared to ITN group (p < 0.001). Complications did not arise more frequently in the LMA group. LMA had to be changed into ITN in 11 cases (5,6 %) only.

CONCLUSION

Our study shows the LMA being a safe and effective alternative to ITN in airway treatment of children undergoing adenoidectomy.

Electrical impedance tomography: changes in distribution of pulmonary ventilation during laparoscopic surgery in a porcine model

BACKGROUND

Because of the creation of a pneumoperitoneum, impairment of ventilation is a common side-effect during laparoscopic surgery. Electrical impedance tomography (EIT) is a method with the potential for becoming a tool to quantify these alterations during surgery. We have studied the change of regional ventilation during and after laparoscopic surgery with EIT and compared the diagnostic findings with computed tomography (CT) scans in a porcine study.

MATERIALS AND METHODS

After approval by the local animal ethics committee, six pigs were included in the study. Two laparoscopic operations were performed [colon resection (n=3) and fundoplicatio (n=3)]. The EIT measurements (6th parasternal intercostal space) were continuously recorded by an EIT prototype (EIT Evaluation Kit, Dräger Medical, Lübeck, Germany). To verify ventilatory alterations detected by EIT, a CT scan was performed postoperatively.

RESULTS

Ventilation with defined tidal volumes was significantly correlated to EIT measurements (r2=0.99). After creation of the pneumoperitoneum, lung compliance typically decreased, which agreed well with an alteration of the distribution of pulmonary ventilation measured by EIT. Elevation of positive end-inspiratory pressure reopened non-aerated lung areas and showed a recovery of the regional ventilation measured by EIT. Additionally, we could detect pulmonary complications by EIT monitoring as verified by CT scans postoperatively.

CONCLUSION

EIT monitoring can be used as a continuous non-invasive intraoperative monitor of ventilation to detect regional changes of ventilation and pulmonary complications during laparoscopic surgery. These EIT findings indicate that surgeons and anesthetists may eventually be able to optimize ventilation directly in the operating theatre.

Unklare intraoperative kardiorespiratorische Dekompensation

During anaesthesia a patient is exposed to a variety of substances, all of which could lead to anaphylactic reactions. In addition, other drugs may exert clinical side-effects by non-immunological mechanisms, e.g. by direct stimulation of the release of histamine by mast cells. Initially, the observed symptoms, such as hypotension or tachycardia, may be misunderstood by the anaesthetist, leading to a possible delay in diagnosis and subsequent treatment of the anaphylactic event. Cardiac ischemia and lung embolisms are important differential diagnoses that often cannot be definitely ruled out during the acute situation and that have to be followed up once the patient has been stabilised. We report a case of anaphylactic reaction after the administration of ampicillin which required treatment and ventilation in the intensive care unit. Despite an accurate determination of serum tryptase levels, the diagnosis of an anaphylactic reaction to ampicillin was eventually confirmed by skin testing. During anaesthesia, anaesthetists should consider anaphylaxis when unforeseen symptoms such as bronchospasm, haemodynamical instability and/or flush arise. In cases of unexpected reactions, patients should undergo allergological follow-up to prevent fatal re-exposure.

Relationship between blood pressure and finger photoplethysmographic waveform during oxygen desaturation test: a model fitting approach

A modified 3-element windkessel model was applied to study the relationship between brachial arterial blood pressure and the photoplethysmographic waveform from pulse oximeters. Data were recorded from 12 healthy volunteers who underwent the oxygen desaturation study. During about 30 minutes recording period, the SpO2 value was regulated down till about 70%. After preprocessing, singular value decomposition (SVD) algorithm was then used to get the best fit of the model parameters.

RESULT

the fitting error (RMSE) was 1.07 +/- 0.48 mmHg. The time constant of the model shown significant difference between the highest and the lowest saturation group.

A prototype device for standardized calibration of pulse oximeters

OBJECTIVE

To develop and test a method for standardized calibration of pulse oximeters.

METHODS

A novel pulse oximeter calibration technique capable of simulating the behavior of real patients is discussed. It is based on an artificial finger with a variable spectral-resolved light attenuator in conjunction with an extensive clinical database of time-resolved optical transmission spectra of patients fingers in the wavelength range 600-1000 nm. The arterial oxygen saturation of the patients at the time of recording was derived by analyzing a corresponding blood sample with a CO-oximeter. These spectra are used to compute the modulation of the light attenuator which is attached to the artificial finger. This calibration method was tested by arbitrarily playing back recorded spectra to pulse oximeters and comparing their display to the value they displayed when the spectra were recorded.

RESULTS

We were able to demonstrate that the calibrator could generate physiological signals which are accepted by a pulse oximeter. We also present some experience of playing back recorded patient spectra. The mean difference between the original reading of the pulse oximeters and the display when attached to the calibrator is 1.2 saturation points (displayed oxygen saturation SpO2) with a standard deviation of 1.9 saturation points.

CONCLUSIONS

The tests have shown the capabilities of a spectral light modulator for use as a possible calibration standard for pulse oximeters. If some improvements of the current prototype can be achieved we conclude from the experience with the device that this novel concept for the calibration of pulse oximeters is feasible and that it could become an important tool for assessing the performance of pulse oximeters.

Accuracy of point-of-care-testing (POCT) for determining hemoglobin concentrations

BACKGROUND

While point-of-care testing (POCT) is being used increasingly as a basis for deciding on perioperative erythrocyte transfusion, no valid standards currently exist concerning the accuracy of Hb concentration measurements. For clinical employment, however, the confidence limits (+/-2 SD) of these measurements should lie close to 5 g/l. The aim of the present study was to evaluate the accuracy and precision of point-of-care testing for blood hemoglobin concentration (cHb in g/l) measurements in critically ill patients.

METHODS

Fifty blood samples from 50 postoperative patients requiring intensive care treatment were withdrawn from a cannula in the radial artery into a 2-ml heparinized syringe (containing wet sodium heparinate in the conus), in a 2-ml Monovette with 50 IE lithium heparinate, and into a 2.7-ml cuvette with 1.6 mg potassium EDTA/ml blood. The POCT battery consisted of two blood gas analyzers (ABLTM 625 and 725, Radiometer, Copenhagen), the HemoCue system (Mallinckrodt Medical, Germany), and an automated hematology analyzer (M-2000(R), Sysmex, Germany). The cyanmethemoglobin method served as the reference 'gold standard' procedure. The blood gas analyzer and HemoCue systems were tested using dry and wet heparinized blood samples.

RESULTS

Hemoglobin concentrations of the reference measurements ranged from 73.9 to 159.4 g/l. The automated hematology analyzer method did reveal a small but systematic deviation for higher cHb values. For the blood gas analyzer and HemoCue system procedures there was no systematic deviation of bias for either the first measurement or the averaged data. Bland & Altman analysis revealed a larger scattering for the wet heparinized samples.

CONCLUSIONS

The above-stated requirement for POCT systems, i.e. that the confidence limits should lie close to 5 g/l cHb, held true for the dry heparinized samples of the blood gas analyzer (1st measurement and mean of 2), the HemoCue system (mean of 3) and the automated hematology analyzer.

Immunophilins and HIV-1 infection

Peptides of the V3 loop of the HIV-1 envelope glycoprotein gp120 have been shown to bind with high affinity to the immunophilins cyclophilin (Cyp) A, CypB and the FK506-binding protein 12 (FKBP12) [10]. We investigated whether immunophilins affect HIV-1 infection by assuming they are able to bind to the V3 loop of gp120. T cells and peripheral blood mononuclear cells were infected with T-cell-tropic or macrophage-tropic HIV-1 strains, respectively, in the presence of different concentrations of immunophilins. P24 antigen ELISA and real-time PCR measurements demonstrated that exogenously added immunophilins do not influence HIV-1 infection. CypA is known to interact with the HIV-1 Gag polyprotein and to be incorporated into the virions. This incorporation can be prevented by cyclosporin A (CsA) resulting in a decreased yield of infectious virus, the mechanism of which is unknown. We measured a normal production of proviral DNA in the first round of infection in CsA treated cells but afterwards, infection was decreased if CsA was present. Pre-treatment of the HIV-1 inocula with CsA, blocking the function of virus-associated CypA, did not inhibit the ensuing yield of infection. We therefore may conclude that endogenous CypA exerts its action after reverse transcription but before virus maturation, probably during capsid formation. FK520, an immunosuppressor which binds to FKBP, had no effect on HIV-1 infection.

Development and evaluation of a video program for presentation prior to elective cardiac surgery

BACKGROUND

: The objective of the present study was to develop and evaluate the effects of a preparatory videotape on endocrine stress responses of patients prior to cardiac surgery and to analyze patient acceptance of this video for preoperative preparation.

METHODS

: 101 male patients prior to elective cardiac surgery were enrolled into the study. On the day before surgery, patients were assigned to one of the following groups: group 1 (n = 51) saw a video with realistic information about the upcoming perioperative procedure, and group 2 (n = 50) saw a video of the same length without surgery-related information. Venous blood was sampled before and 15 min after the video presentation. On the second postoperative day, patients filled in a questionnaire concerning their experiences of having preoperatively watched the video.

RESULTS

: After viewing the video, blood levels of cortisol, adrenocorticotropic hormone (ACTH), beta-endorphin, prolactin, epinephrine and norepinephrine in patients of group 1 were not significantly different compared to values measured before the video presentation. In patients of group 2, blood levels of cortisol, ACTH, prolactin and norepinephrine were significantly lower after video presentation compared to values obtained before the video. Patients of group 1 (compared to group 2) were significantly more often of the opinion that the video had helped in the preparation for surgery, and that they would like to repeat this adjunct preoperative video preparation in another similar situation.

CONCLUSION

: We conclude from our results that (i); cardiac surgical patients prefer preoperatively an adjunct surgery-related video preparation to a non-specific video presentation, and that (ii); preoperative preparation with realistic information about the upcoming medical procedure in patients undergoing cardiac surgery does not lead to an increase in endocrine stress hormone levels.

A prototype device for standardized calibration of pulse oximeters II

OBJECTIVE

There is no commonly accepted in vivo calibration method for pulse oximeters available up to now. On the basis of a prototype device for the calibration of pulse oximeters which was introduced recently, a second approach based on the same concept was tackled in order to design a reliable method for standardized calibration of pulse oximeters.

METHODS

An extensive clinical database of time-resolved optical transmission spectra of patient fingers is used to simulate the behavior of patients. A device which is capable of playing back these spectroscopic data to pulse oximeters, and a database where the oxygen status measured with the reference method (Co-Oximetry) is stored, are the main parts of the concept. The playback device has an artificial finger as interface to the pulse oximeters and serves to collect light from the pulse oximeter for analysis and to playback simulated light to the pulse oximeter. The light intensity emitted by two LEDs which illuminates the pulse oximeter detector is controlled via a computer in such a way that it is the same as if the pulse oximeter light had passed the finger. The pulse oximeter display during the data playback can thus be compared to the true SaO2 of the patient. The device is tested with 4 pulse oximeters based on 100 patient spectra.

RESULTS

For the four pulse oximeters used in this investigation, an Agilent Technologies CMS monitor (formerly Hewlett-Packard), an Ivy 2000 with Masimo Set technology and Nellcor N-3000 and N-395, there is good correlation between SPO2 and SaO2, and mean and standard deviation of in vivo SpO2-SaO2 and playback SpO2-SaO2 are in good agreement. For two instruments, Nellcor N3000 and Agilent CMS Monitor, a quantitative comparison between the in vivo and in vitro SpO, results was derived. A mean of the deviation playback vs. in vivo SpO2 is less than 0.5% SpO2. The error limits are comparable with the calibration error of the conventional calibration routine. The device is also capable of data playback even in situations with rapid desaturation changes, as displayed in Figure 2. For the other tested pulse oximeters the results are comparable.

CONCLUSIONS

Compared to the first prototype the current version is simpler and less expensive in production. Many of previously existing problems are solved and the applicability to a large variety of pulse oximeters and sensors is given. The novel concept for the calibration of pulse oximeters is a tool for assessing the performance of pulse oximeters.

Detecting and quantifying absorbed irrigation fluid by measuring mannitol and sorbitol concentrations in serum samples, and by ethanol monitoring

OBJECTIVE

To describe a modified and improved technique which, in one measurement, estimates the influx of irrigation fluid during endoscopic endometrial ablation or prostate resection, and provides both rapid confirmation of the diagnosis and an estimate of the amount of fluid absorbed by detecting markers which pass from the irrigation fluid to the serum, i.e. mannitol or sorbitol.

PATIENTS AND METHODS

Control samples were taken for analysis before irrigation, and test samples were taken on four occasions during and after intervention, from each of 10 patients undergoing transurethral resection of the prostate. Irrigation fluid was also marked with ethanol (1.5% w/v) and the concentration of this agent measured in the blood and expired air of these patients. The absorbed volume was calculated according to the extracellular distribution space of mannitol.

RESULTS

Mannitol and sorbitol could be measured in 85% and 73% of the 40 test samples, respectively. The threshold for full sensitivity for breath ethanol concentration to detect absorption was 132 mL.

CONCLUSION

This method for detecting serum mannitol and sorbitol represents a valid procedure for confirming and quantifying the absorption of irrigation fluid in the clinic, which agrees closely with the already established ethanol monitoring procedure and which should now be considered as a reference procedure.

Design and validation of a pulse oximeter calibrator

The performance of a new calibrator for pulse oximeters is tested with five pulse oximeters from different manufacturers. The calibrator is based on time resolved transmission spectra of human fingers. Finger spectra with different arterial oxygen saturation can be selected to simulate real patients. The results obtained with this calibration device are compared with the results of conventional calibration procedures with volunteers. Beside accuracy tests the suitability for artifact simulation with the new device is discussed. The response of the five tested pulse oximeters is in good agreement with the response of the pulse oximeters connected to real patients. A test procedure for pulse oximeters similar to the conventional desaturation practice is possible; some of the typical artifacts pulse oximetry has to cope with can be simulated easily.

Inter-individual differences in cytokine release in patients undergoing cardiac surgery with cardiopulmonary bypass

Cardiac surgery with cardiopulmonary bypass (CPB) leads to a systemic inflammatory response with secretion of cytokines (e.g. IL-6, TNF-alpha, IL-1 beta and sIL-2R). The objective of the following study was to investigate in vitro and in vivo cytokine responses and white blood cell counts (WBC) of patients with high versus low cytokine secretion after a coronary artery bypass grafting (CABG) procedure. Twenty male patients undergoing elective CABG surgery with CPB under general anaesthesia were enrolled in the study. On the day of surgery (postoperatively), serum levels of TNF-alpha and IL-1 beta were significantly higher in patients of the high IL-6 level group compared to the respective values in the patient group with low IL-6 levels. The inter-individual differences in IL-6 release in patients undergoing CABG surgery with CPB were accompanied by differences in the release of other cytokines, such as TNF-alpha, IL-1 beta and sIL-2R. To understand whether genetic background plays a role in influencing cytokine plasma levels under surgical stress, we examined the distribution of polymorphic elements within the promoter regions of the TNF-alpha and IL-6 genes, and determined their genotype regarding the BAT2 gene and TNF-beta intron polymorphisms. Our preliminary data suggests that regulatory polymorphisms in or near the TNF locus, more precisely the allele set 140/150 of the BAT2 microsatellite marker combined with the G allele at -308 of the TNF-alpha gene, could be one of the genetic constructions providing for a less sensitive response to various stimuli. Our results suggest: (1) close relationships between cytokine release in the postoperative period, and (2) inter-individually varying patterns of cytokine release in patients undergoing CABG surgery with CPB.

Exposure on cell surface and extensive arginine methylation of ewing sarcoma (EWS) protein

In contrast to the knowledge regarding the function of chimeric Ewing sarcoma (EWS) fusion proteins that arise from chromosomal translocation, the cellular function of the RNA binding EWS protein is poorly characterized. EWS protein had been found mainly in the nucleus. In this report we show that EWS protein is not only found in the nucleus and cytosol but also on cell surfaces. After cell-surface biotinylation, isoelectric focusing of membrane fraction, avidin-agarose extraction of biotinylated proteins, and SDS-polyacrylamide gel electrophoresis, EWS protein was identified by matrix-assisted laser desorption ionization and nanoelectrospray tandem mass spectrometry of in-gel-digested peptides. These analyses revealed that the protein, having repeated RGG motifs, is extensively asymmetrically dimethylated on arginine residues, the sites of which have been mapped by mass spectrometric methods. Out of a total of 30 Arg-Gly sequences, 29 arginines were found to be at least partially methylated. The Arg-Gly-Gly sequence was present in 21 of the 29 methylation sites, and in contrast to other methylated proteins, only 11 (38%) methylated arginine residues were found in the Gly-Arg-Gly sequence. The presence of Gly on the C-terminal side of the arginine residue seems to be a prerequisite for recognition by a protein-arginine N-methyltransferase (PRMT) catalyzing this asymmetric dimethylation reaction. One monomethylarginine and no symmetrically methylated arginine residue was found. The present findings imply that RNA-binding EWS protein shuttles from the nucleus to the cell surface in a methylated form, the role of which is discussed.