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Background: Laparoscopy training has become an integral part of surgical education. Suturing and knot tying is a basic, yet inherent part of many laparoscopic operations, and should be mastered prior to operating on patients. One common and standardized suturing technique is the C-loop technique. In the standard training setting, on a box trainer, the trainee learns the psychomotor movements of the task and the laparoscopic visuospatial orientation simultaneously. Learning the psychomotor and visuospatial skills separately and sequentially may offer a more time-efficient alternative to the current standard of training., Methods: This is a monocentric, two-arm randomized controlled trial. The participants are medical students in their clinical years (third to sixth year) at Heidelberg University who have not previously partaken in a laparoscopic training course lasting more than 2 hours. A total of 54 students are randomized into one of two arms in a 1:1 ratio to sequential learning (group 1) or control (group 2). Both groups receive a standardized introduction to the training center, laparoscopic instruments, and C-loop technique. Group 1 learn the C-loop using a transparent shoebox, thus only learning the psychomotor skills. Once they reach proficiency, they then perform the same knot tying procedure on a box trainer with standard laparoscopic view, where they combine their psychomotor skills with the visuospatial orientation inherent to laparoscopy. Group 2 learn the C-loop using solely a box trainer with standard laparoscopic view until they reach proficiency. Trainees work in pairs and time is recorded for each attempt. The primary outcome is mean total training time for each group. Secondary endpoints include procedural and knot quality subscore differences. Tertiary endpoints include studying the influence of gender and video game experience on performance., Discussion: This study addresses whether the learning of the psychomotor and visuospatial aspects of laparoscopic suturing and knot tying is optimal sequentially or simultaneously, by assessing total training time, procedural, and knot quality differences between the two groups. It will improve the efficiency of future laparoscopic suturing courses and may serve as an indicator for laparoscopic training in a broader context, i.e., not only for suturing and knot tying., Trial Registration: This trial was registered on 12 August 2015 with the trial registration number DRKS00008668 .

Purpose: The validated Objective Structured Assessment of Technical Skills (OSATS) score is used for evaluating laparoscopic surgical performance. It consists of two subscores, a Global Rating Scale (GRS) and a Specific Technical Skills (STS) scale. The OSATS has accepted construct validity for direct observation ratings by experts to discriminate between trainees' levels of experience. Expert time is scarce. Endoscopic video recordings would facilitate assessment with the OSATS. We aimed to compare video OSATS with direct OSATS., Methods: We included 79 participants with different levels of experience [58 medical students, 15 junior residents (novices), and 6 experts]. Performance of a cadaveric porcine laparoscopic cholecystectomy (LC) was evaluated with OSATS by blinded expert raters by direct observation and then as an endoscopic video recording. Operative time was recorded., Results: Direct OSATS rating and video OSATS rating correlated significantly (x03C1; = 0.33, p = 0.005). Significant construct validity was found for direct OSATS in distinguishing between students or novices and experts. Students and novices were not different in direct OSATS or video OSATS. Mean operative times varied for students (73.4 ± 9.0 min), novices (65.2 ± 22.3 min), and experts (46.8 ± 19.9 min). Internal consistency was high between the GRS and STS subscores for both direct and video OSATS with Cronbach's α of 0.76 and 0.86, respectively. Video OSATS and operative time in combination was a better predictor of direct OSATS than each single parameter., Conclusion: Direct OSATS rating was better than endoscopic video rating for differentiating between students or novices and experts for LC and should remain the standard approach for the discrimination of experience levels. However, in the absence of experts for direct rating, video OSATS supplemented with operative time should be used instead of single parameters for predicting direct OSATS scores., (© 2016 S. Karger AG, Basel.)

Background: Minimally invasive surgery (MIC) requires surgeons to have a different set of skills and capabilities from that of open surgery. The indirect camera view, lack of a three-dimensional view, restricted haptic feedback with lack of tissue feeling and difficult instrument coordination with fulcrum and pivoting effects result in an additional learning curve compared to open surgery. The prolonged learning curve leads to a higher risk of complications and special awareness of these risks is therefore mandatory. Training of special laparoscopic skills outside the operating room is needed to optimize patient outcome and to minimize the ocurrence of complications related to the learning curve., Results and Discussion: Training modalities for laparoscopic surgery include simple box trainers, computer simulation with virtual reality, the use of artificial and cadaver organs, as well as live animal models and cadaver training. These training modalities have been proven in studies to have a beneficial effect on the learning curve for acquisition of laparoscopic skills and for improving operative performance as well as avoidance of complications. Laparoscopic training is currently gaining a more and more important role for official education and accreditation purposes. In some countries the participation in laparoscopic training courses has become mandatory prior to participation in laparoscopic operations. Future research will include the optimization of multimodal training curricula, the development of individualized training approaches that allow both trainee and patient-specific preparation, as well as the use of novel devices to facilitate the collection and transfer of expertise between the generations and schools of surgeons.

The spin-reorientation transition (SRT) in epitaxial NixPd1-x/Cu(001) is studied by photoemission microscopy utilizing the X-ray magnetic circular dichroism effect at the Ni L2,3 edge. In a composition/thickness wedged geometry, a composition driven SRT could be observed between 37 ML and 60 ML, and 0 and 38% of Pd. Microspectroscopy in combination with azimuthal sample rotation confirms a magnetization preference changing from the [001] to an in-plane easy axis. At this increased thickness, the domain patterns arrange comparable to SRTs in ultrathin films. The images document domains equivalent to a canted state SRT, at which an additional effect of in-plane anisotropies could be identified., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: Apart from animal testing and clinical trials, surgical research and laparoscopic training mainly rely on phantoms. The aim of this project was to design a phantom with realistic anatomy and haptic characteristics, modular design and easy reproducibility. The phantom was named open-source Heidelberg laparoscopic phantom (OpenHELP) and serves as an open-source platform., Methods: The phantom was based on an anonymized CT scan of a male patient. The anatomical structures were segmented to obtain digital three-dimensional models of the torso and the organs. The digital models were materialized via rapid prototyping. One flexible, using an elastic abdominal wall, and one rigid method, using a plastic shell, to simulate pneumoperitoneum were developed. Artificial organ production was carried out sequentially starting from raw gypsum models to silicone molds to final silicone casts. The reproduction accuracy was exemplarily evaluated for ten silicone rectum models by comparing the digital 3D surface of the original rectum with CT scan by calculating the root mean square error of surface variations. Haptic realism was also evaluated to find the most realistic silicone compositions on a visual analog scale (VAS, 0-10)., Results: The rigid and durable plastic torso and soft silicone organs of the abdominal cavity were successfully produced. A simulation of pneumoperitoneum could be created successfully by both methods. The reproduction accuracy of ten silicone rectum models showed an average root mean square error of 2.26 (0-11.48) mm. Haptic realism revealed an average value on a VAS of 7.25 (5.2-9.6) for the most realistic rectum., Conclusion: The OpenHELP phantom proved to be feasible and accurate. The phantom was consecutively applied frequently in the field of computer-assisted surgery at our institutions and is accessible as an open-source project at www.open-cas.org for the academic community.

Introduction: Mesh augmentation seems to reduce recurrences following laparoscopic paraesophageal hernia repair (LPHR). However, there is an uncertain risk of mesh-associated complications. Risk-benefit analysis might solve the dilemma., Materials and Methods: A systematic literature search was performed to identify randomized controlled trials (RCTs) and observational clinical studies (OCSs) comparing laparoscopic mesh-augmented hiatoplasty (LMAH) with laparoscopic mesh-free hiatoplasty (LH) with regard to recurrences and complications. Random effects meta-analyses were performed to determine potential benefits of LMAH. All data regarding LMAH were used to estimate risk of mesh-associated complications. Risk-benefit analysis was performed using a Markov Monte Carlo decision-analytic model., Results: Meta-analysis of 3 RCTs and 9 OCSs including 915 patients revealed a significantly lower recurrence rate for LMAH compared to LH (pooled proportions, 12.1% vs. 20.5%; odds ratio (OR), 0.55; 95% confidence interval (CI), 0.34 to 0.89; p = 0.04). Complication rates were comparable in both groups (pooled proportions, 15.3% vs. 14.2%; OR, 1.02; 95% CI, 0.63 to 1.65; p = 0.94). The systematic review of LMAH data yielded a mesh-associated complication rate of 1.9% (41/2121; 95% CI, 1.3% to 2.5%) for those series reporting at least one mesh-associated complication. The Markov Monte Carlo decision-analytic model revealed a procedure-related mortality rate of 1.6% for LMAH and 1.8% for LH., Conclusions: Mesh application should be considered for LPHR because it reduces recurrences at least in the mid-term. Overall procedure-related complications and mortality seem to not be increased despite of potential mesh-associated complications.

Spin crossover (SCO) complexes possess a bistable spin state that reacts sensitively to changes in temperature or excitation with light. These effects have been well investigated in solids and solutions, while technological applications require the immobilization and contacting of the molecules at surfaces, which often results in the suppression of the SCO. We report on the thermal and light-induced SCO of [Fe(bpz)2phen] molecules in direct contact with a highly oriented pyrolytic graphite surface. We are able to switch on the magnetic moment of the molecules by illumination with green light at T = 6 K, and off by increasing the temperature to 65 K. The light-induced switching process is highly efficient leading to a complete spin conversion from the low-spin to the high-spin state within a submonolayer of molecules. [Fe(bpz)2phen] complexes immobilized on weakly interacting graphite substrates are thus promising candidates to realize the vision of an optically controlled molecular logic unit for spintronic devices.

This study compared virtual reality (VR) training with low cost-blended learning (BL) in a structured training program.Training of laparoscopic skills outside the operating room is mandatory to reduce operative times and risks.Laparoscopy-naïve medical students were randomized in 2 groups stratified for sex. The BL group (n = 42) used E-learning for laparoscopic cholecystectomy (LC) and practiced basic skills with box trainers. The VR group (n = 42) trained basic skills and LC on the LAP Mentor II (Simbionix, Cleveland, OH). Each group trained 3 × 4 hours followed by a knowledge test concerning LC. Blinded raters assessed the operative performance of cadaveric porcine LC using the Objective Structured Assessment of Technical Skills (OSATS). The LC was discontinued when it was not completed within 80 min. Students evaluated their training modality with questionnaires.The VR group completed the LC significantly faster and more often within 80 min than BL (45% v 21%, P = .02). The BL group scored higher than the VR group in the knowledge test (13.3 ± 1.3 vs 11.0 ± 1.7, P < 0.001). Both groups showed equal operative performance of LC in the OSATS score (49.4 ± 10.5 vs 49.7 ± 12.0, P = 0.90). Students generally liked training and felt well prepared for assisting in laparoscopic surgery. The efficiency of the training was judged higher by the VR group than by the BL group.VR and BL can both be applied for training the basics of LC. Multimodality training programs should be developed that combine the advantages of both approaches.

Background: Computer-assisted surgery is a wide field of technologies with the potential to enable the surgeon to improve efficiency and efficacy of diagnosis, treatment, and clinical management., Purpose: This review provides an overview of the most important new technologies and their applications., Methods: A MEDLINE database search was performed revealing a total of 1702 references. All references were considered for information on six main topics, namely image guidance and navigation, robot-assisted surgery, human-machine interface, surgical processes and clinical pathways, computer-assisted surgical training, and clinical decision support. Further references were obtained through cross-referencing the bibliography cited in each work. Based on their respective field of expertise, the authors chose 64 publications relevant for the purpose of this review., Conclusion: Computer-assisted systems are increasingly used not only in experimental studies but also in clinical studies. Although computer-assisted abdominal surgery is still in its infancy, the number of studies is constantly increasing, and clinical studies start showing the benefits of computers used not only as tools of documentation and accounting but also for directly assisting surgeons during diagnosis and treatment of patients. Further developments in the field of clinical decision support even have the potential of causing a paradigm shift in how patients are diagnosed and treated.

Background: Intracorporeal suturing and knot tying (ICKT) in minimal invasive surgery (MIS) represents a key skill for advanced procedures. Different methods exist for measuring knot quality and performance, but the heterogeneity of these methods makes direct comparisons difficult. The aim of this study is to compare the quality of a laparoscopic knot to one that is performed open., Methods: To compare open and laparoscopic knot-tying methods we used a surgeon's square knot. For laparoscopic knot tying we used a Pelvitrainer. The 32 participants were divided among 4 groups of different skill levels. Group 1 consisted of 6 senior physicians. Group 2 was made up of 10 first to fourth year interns. Groups 3 and 4 contained 16 medical students who had never performed either laparoscopic procedures or open sutures before. Group 3 participants received a 1-hour hands-on training in suturing, whereas group 4 participants received no prior training. Total time, knot quality, suture placement accuracy, and performance defined the parameters for assessment in this study., Results: All participants, irrespective of education level were inferior in ICKT compared to open suturing. Only Group 1 showed no significant difference in knot quality and accuracy between the open and laparoscopic suture performance., Conclusion: It is well documented that psychomotor skills need to be developed before more advanced skills can be put into practice. Training centres for minimally invasive surgery should be an integral part of surgical education. The variables in our study are meaningful and easy to implement. They can be used to measure personal progress and as objective parameters in the development of laparoscopic trainee education., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: The effect of bariatric surgery on weight loss and improvement of co-morbidities is no longer doubted. However, little attention has been given to the treatment goals from the patient's point of view (patient expectations). The objective of this study was to examine patients' expectations of bariatric surgery and identify gender differences., Methods: Bariatric patients were asked to complete a questionnaire. Statistical analysis was performed using chi-square, Pearson correlation coefficient, and Wilcoxon rank sum test., Results: Overall, 248 patients participated in this study (69.4% females). The male patients (45.2 yr, SD±11.1) were significantly older than the female (41.8 yr, SD±12.0; P = .04) and suffered significantly more often from diabetes, hypertension, hypercholesterolemia, and sleep apnea. One hundred thirty patients (52.4%) expected to lose at least 45 kg and 39 patients (15.7%)>70 kg. The mean expected excess weight loss was 71.8%. Females expected significantly more often that surgery alone would induce weight loss (P = .03). "Improved co-morbidity" was by far the highest ranked parameter., Conclusion: The male bariatric surgery patients were older and suffered from more co-morbidities. Most of the patients had unrealistic weight loss goals and overestimated the effect of the surgical intervention. However, for both female and male patients, "improved co-morbidity" was the most important issue., (Copyright © 2014 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Laparoscopy training courses have been established in many centers worldwide to ensure adequate skill learning before performing operations on patients. Different training modalities and their combinations have been compared regarding training effects. Multimodality training combines different approaches for optimal training outcome. However, no standards currently exist for the number of trainees assigned per workplace., Methods: This is a monocentric, open, three-arm randomized controlled trial. The participants are laparoscopically-naive medical students from Heidelberg University. After a standardized introduction to laparoscopic cholecystectomy (LC) with online learning modules, the participants perform a baseline test for basic skills and LC performance on a virtual reality (VR) trainer. A total of 100 students will be randomized into three study arms, in a 2:2:1 ratio. The intervention groups participate individually (Group 1) or in pairs (Group 2) in a standardized and structured multimodality training curriculum. Basic skills are trained on the box and VR trainers. Procedural skills and LC modules are trained on the VR trainer. The control group (Group C) does not receive training between tests. A post-test is performed to reassess basic skills and LC performance on the VR trainer. The performance of a cadaveric porcine LC is then measured as the primary outcome using standardized and validated ratings by blinded experts with the Objective Structured Assessment of Technical Skills. The Global Operative Assessment of Laparoscopic Surgical skills score and the time taken for completion are used as secondary outcome measures as well as the improvement of skills and VR LC performance between baseline and post-test. Cognitive tests and questionnaires are used to identify individual factors that might exert influence on training outcome., Discussion: This study aims to assess whether workplaces in laparoscopy training courses for beginners should be used by one trainee or two trainees simultaneously, by measuring the impact on operative performance and learning curves. Possible factors of influence, such as the role of observing the training partner, exchange of thoughts, active reflection, model learning, motivation, pauses, and sympathy will be explored in the data analysis. This study will help optimize the efficiency of laparoscopy training courses., Trial Registration Number: DRKS00004675.

Background: Laparoscopic liver surgery is particularly challenging owing to restricted access, risk of bleeding, and lack of haptic feedback. Navigation systems have the potential to improve information on the exact position of intrahepatic tumors, and thus facilitate oncological resection. This study aims to evaluate the feasibility of a commercially available augmented reality (AR) guidance system employing intraoperative robotic C-arm cone-beam computed tomography (CBCT) for laparoscopic liver surgery., Methods: A human liver-like phantom with 16 target fiducials was used to evaluate the Syngo iPilot(®) AR system. Subsequently, the system was used for the laparoscopic resection of a hepatocellular carcinoma in segment 7 of a 50-year-old male patient., Results: In the phantom experiment, the AR system showed a mean target registration error of 0.96 ± 0.52 mm, with a maximum error of 2.49 mm. The patient successfully underwent the operation and showed no postoperative complications., Conclusion: The use of intraoperative CBCT and AR for laparoscopic liver resection is feasible and could be considered an option for future liver surgery in complex cases.

Background: Habituation to repetitive noxious stimuli is a well-known phenomenon. We investigated brain correlates of habituation to pain in a transdermal electrical pain model using functional magnetic resonance imaging (fMRI)., Methods: Electrical painful stimulation with 1 Hz was applied to the volar forearm of 48 healthy subjects for 45 min. Before and after conditioning stimulation, psychophysical testing and fMRI were performed. During fMRI sessions, the subjects underwent blockwise painful electrical stimulation with a fixed percept-adapted current intensity. After fMRI 1 and fMRI 2 subjects rated the individual pain intensity of the electrical stimulus., Results: Substantial habituation occurred during conditioning electrical stimulation. Accordingly, areas typically involved in pain processing showed decreased activity after conditioning stimulation. The blood oxygen level-dependent signal of the subgenual anterior cingulate gyrus, the superior parietal lobule and the supplemental motor area correlated positively with habituation. In contrast, activity in the periaqueductal grey, thalamus and insula correlated negatively. The results of the correlation analyses did not survive correction for multiple comparisons., Conclusions: With this study, we identified central components associated with habituation to repetitive painful stimuli. The results suggest that an increase in tonic inhibitory activity in cortical pain processing areas is a major mechanism contributing to habituation to phasic noxious stimuli. Moreover, areas involved in descending pain modulation were differentially modulated. This may hint at a simultaneous activation of facilitating and inhibiting nociceptive systems that are both altered in the transdermal electrical pain model., (© 2013 European Pain Federation - EFIC®)

Submono-, mono- and multilayers of the Fe(II) spin-crossover (SCO) complex [Fe(bpz)2 (phen)] (bpz=dihydrobis(pyrazolyl)borate, phen=1,10-phenanthroline) have beenprepared by vacuum deposition on Au(111) substrates and investigated with near edge X-ray absorption fine structure (NEXAFS) spectroscopy and scanning tunneling microscopy (STM). As evidenced by NEXAFS, molecules of the second layer exhibit a thermal spin crossover transition, although with a more gradual characteristics than in the bulk. For mono- and submonolayers of [Fe(bpz)2 (phen)] deposited on Au(111) substrates at room temperature both NEXAFS and STM indicate a dissociation of [Fe(bpz)2 (phen)] on Au(111) into four-coordinate complexes, [Fe(bpz)2 ], and phen molecules. Keeping the gold substrate at elevated temperatures ordered monolayers of intact molecules of [Fe(bpz)2 (phen)] are formed which can be spin-switched by electron-induced excited spin-state trapping (ELIESST)., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: Surprisingly, 40% to 95% of patients with type 2 diabetes mellitus (T2DM) show early remission of hyperglycemia after obesity surgery. It is unknown to what extent other diabetes-associated comorbidities such as distal peripheral neuropathy (DPN) might be influenced by obesity surgery. This pilot study aimed at providing further evidence for the impact of Roux-en-Y gastric bypass (RYGB) on both glycemic control and DPN in non-severely obese patients with insulin-dependent T2DM., Methods: In the present prospective cohort study, 20 patients with long-standing, insulin-dependent T2DM and a body mass index (BMI) between 25 and 35 kg/m underwent laparoscopic RYGB. Body mass index, glycosylated hemoglobin (HbA1c), and DPN [quantified by the Neuropathy Symptom Score (NSS) and the Neuropathy Deficit Score (NDS)] were investigated., Results: Six months after surgery, the preoperative BMI of 32.8 ± 2.1 kg/m (mean ± standard deviation) dropped to 25.6 ± 2.5 kg/m (P < 0.001). Preoperative HbA1c levels decreased from 8.5 ± 1.2% to 7.1 ± 1.2% (P < 0.001), with 15% of patients having a normalized HbA1c level lower than 6.2%. Of 12 patients with documented DPN, the median NSS was 8 (range, 0-10) preoperatively and 0 (range, 0-9) postoperatively (P = 0.004), with 8 patients scoring an NSS of 0. The median NDS was 6 (range, 2-8) preoperatively and 4 (range, 0-8) postoperatively (P = 0.027), with 1 patient scoring an NDS of 0. All patients had an improvement or normalization in either 1 or both scores., Conclusions: As expected, BMI and HbA1c levels improved significantly after RYGB. More interestingly, neuropathy scores, such as NSS and NDS, improved significantly early after surgery. Symptomatic neuropathy was completely reversible in 67% of the patients. These findings add further evidence to the fact that RYGB might be a valuable treatment option not only for improving glycemic control but also for reducing diabetes-associated comorbidities, such as DPN. This points to a complex metabolic effect of RYGB that exceeds glucose normalization. However, the results still need to be confirmed in controlled trials.

Background: Navigation systems potentially facilitate minimally invasive esophagectomy and improve patient outcome by improving intraoperative orientation, position estimation of instruments, and identification of lymph nodes and resection margins. The authors' self-developed navigation system is highly accurate in static environments. This study aimed to test the overall accuracy of the navigation system in a realistic operating room scenario and to identify the different sources of error altering accuracy., Methods: To simulate a realistic environment, a porcine model (n = 5) was used with endoscopic clips in the esophagus as navigation targets. Computed tomography imaging was followed by image segmentation and target definition with the medical imaging interaction toolkit software. Optical tracking was used for registration and localization of animals and navigation instruments. Intraoperatively, the instrument was displayed relative to segmented organs in real time. The target registration error (TRE) of the navigation system was defined as the distance between the target and the navigation instrument tip. The TRE was measured on skin targets with the animal in the 0° supine and 25° anti-Trendelenburg position and on the esophagus during laparoscopic transhiatal preparation., Results: On skin targets, the TRE was significantly higher in the 25° position, at 14.6 ± 2.7 mm, compared with the 0° position, at 3.2 ± 1.3 mm. The TRE on the esophagus was 11.2 ± 2.4 mm. The main source of error was soft tissue deformation caused by intraoperative positioning, pneumoperitoneum, surgical manipulation, and tissue dissection., Conclusion: The navigation system obtained acceptable accuracy with a minimally invasive transhiatal approach to the esophagus in a realistic experimental model. Thus the system has the potential to improve intraoperative orientation, identification of lymph nodes and adequate resection margins, and visualization of risk structures. Compensation methods for soft tissue deformation may lead to an even more accurate navigation system in the future.

Background: Bouveret's syndrome causes gastric outlet obstruction when a gallstone is impacted in the duodenum or stomach via a bilioenteric fistula. It is a rare condition that causes significant morbidity and mortality and often occurs in the elderly with significant comorbidities. Individual diagnostic and treatment strategies are required for optimal management and outcome. The purpose of this paper is to develop a surgical strategy for optimized individual treatment of Bouveret's syndrome based on the available literature and motivated by our own experience., Case Presentation: Two cases of Bouveret's syndrome are presented with individual management and restrictive surgical approaches tailored to the condition of the patients and intraoperative findings., Conclusions: Improved diagnostics and restrictive individual surgical approaches have shown to lower the mortality rates of Bouveret's syndrome. For optimized outcome of the individual patient: The medical and perioperative management and time of surgery are tailored to the condition of the patient. CT-scan is most often required to secure the diagnosis. The surgical approach includes enterolithotomy alone or in combination with simultaneous or subsequent cholecystectomy and fistula repair. Lower overall morbidity and mortality are in favor of restrictive surgical approaches. The surgical strategy is adapted to the intraoperative findings and to the risk for secondary complications vs. the age and comorbidities of the patient.

Purpose: In image-guided surgery (IGS) intraoperative image acquisition of tissue shape, motion, and morphology is one of the main challenges. Recently, time-of-flight (ToF) cameras have emerged as a new means for fast range image acquisition that can be used for multimodal registration of the patient anatomy during surgery. The major drawbacks of ToF cameras are systematic errors in the image acquisition technique that compromise the quality of the measured range images. In this paper, we propose a calibration concept that, for the first time, accounts for all known systematic errors affecting the quality of ToF range images. Laboratory and in vitro experiments assess its performance in the context of IGS., Methods: For calibration the camera-related error sources depending on the sensor, the sensor temperature and the set integration time are corrected first, followed by the scene-specific errors, which are modeled as function of the measured distance, the amplitude and the radial distance to the principal point of the camera. Accounting for the high accuracy demands in IGS, we use a custom-made calibration device to provide reference distance data, the cameras are calibrated too. To evaluate the mitigation of the error, the remaining residual error after ToF depth calibration was compared with that arising from using the manufacturer routines for several state-of-the-art ToF cameras. The accuracy of reconstructed ToF surfaces was investigated after multimodal registration with computed tomography (CT) data of liver models by assessment of the target registration error (TRE) of markers introduced in the livers., Results: For the inspected distance range of up to 2 m, our calibration approach yielded a mean residual error to reference data ranging from 1.5±4.3 mm for the best camera to 7.2±11.0 mm. When compared to the data obtained from the manufacturer routines, the residual error was reduced by at least 78% from worst calibration result to most accurate manufacturer data. After registration of the CT data with the ToF data, the mean TRE ranged from 3.7±2.1 mm for point-based and 5.7±1.9 mm for surface-based registration for the best camera to 6.2±3.4 and 11.1±2.8 mm, respectively. Compared to data provided by the manufacturer, the mean TRE decreased by 8%-60% for point-based and by 18%-74% for surface-based registration., Conclusions: Using the proposed calibration approach improved the measurement accuracy of all investigated ToF cameras. Although evaluated in the context of intraoperative image acquisition, the proposed calibration procedure can easily be applied to other medical applications using ToF cameras, such as patient positioning or respiratory motion tracking in radiotherapy.

We report on the implementation and usage of a synchrotron-based time-resolving operation mode in an aberration-corrected, energy-filtered photoemission electron microscope. The setup consists of a new type of sample holder, which enables fast magnetization reversal of the sample by sub-ns pulses of up to 10 mT. Within the sample holder current pulses are generated by a fast avalanche photo diode and transformed into magnetic fields by means of a microstrip line. For more efficient use of the synchrotron time structure, we developed an electrostatic deflection gating mechanism capable of beam blanking within a few nanoseconds. This allows us to operate the setup in the hybrid bunch mode of the storage ring facility, selecting one or several bright singular light pulses which are temporally well-separated from the normal high-intensity multibunch pulse pattern., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: The purpose of the present study was to determine the value of virtual reality (VR) training for a multimodality training program of basic laparoscopic surgery., Materials and Methods: Participants in a two-day multimodality training for laparoscopic surgery used box trainers, live animal training, and cadaveric training on the pulsating organ perfusion (POP) trainer in a structured and standardized training program. The participants were divided into two groups. The VR group (n = 13) also practiced with VR training during the program, whereas the control group (n = 14) did not use VR training. The training modalities were assessed using questionnaires with a five-point Likert scale after the program. Concerning VR training, members of the control group assessed their expectations, whereas the VR group assessed the actual experience of using it. Skills performance was evaluated with five standardized test tasks in a live porcine model before (pre-test) and after (post-test) the training program. Laparoscopic skills were measured by task completion time and a general performance score for each task. Baseline tests were compared with laparoscopic experience of all participants for construct validity of the skills test., Results: The expected benefit from VR training of the control group was higher than the experienced benefit of the VR group. Box and POP training received better ratings from the VR group than from the control group for some purposes. Both groups improved their skill parameters significantly from pre-training to post-training tests [score +17 % (P < 0.01), time -29 % (P < 0.01)]. No significant difference was found between the two groups for laparoscopic skills improvement except for the score in the instrument coordination task. Construct validity of the skills test was significant for both time and score., Conclusions: At its current level of performance, VR training does not meet expectations. No additional benefit was observed from VR training in our multimodality training program.

Purpose: To compare two methods of creating three-dimensional representations of mandibular cysts and tumors on the basis of computed tomography (CT) and cone beam computed tomography (CBCT) data., Methods: A total of 71 patients with acquired jaw cysts took part in this retrospective clinical study. CT and CBCT scans were obtained from all patients and saved in the Digital Imaging and Communications in Medicine (DICOM) format. Data were analyzed twice with iPlan software. Analysis was performed manually and using an interpolarization algorithm. The accuracy of the two methods in assessing cyst volume was compared., Results: Manual delineation did not provide more accurate results than the interpolarization algorithm., Conclusion: There are no major differences between manual analysis and analysis using the interpolarization algorithm. The use of the algorithm, however, has the advantage of rapidity.

In recent years, robotic assistance for surgical procedures has grown on a worldwide scale, particularly for use in more complex operations. Such operations usually require meticulous handling of tissue, involve a narrow working space and limit the surgeon's sense of orientation in the human body. Improvement in both tissue handling and working within a narrow working space might be achieved through the use of robotic assistance. Soft tissue navigation might improve orientation by visualizing important target and risk structures intraoperatively, thereby possibly improving patient outcome. Prerequisites for navigation are its integration into the surgical workflow and accurate localization of both the instruments and patient. Magnetic tracking allows for good integration but is susceptible to distortion through metal or electro-magnetic interference, which may be caused by the operation table or a robotic system. We have investigated whether magnetic tracking can be used in combination with the da Vinci(®) (DV) telemanipulator in terms of stability and precision. We used a common magnetic tracking system (Aurora(®), NDI Inc.) with the DV in a typical operation setup. Magnetic field distortion was evaluated using a measuring facility, with the following reference system: without any metal (R), operation table alone (T), DV in standby (D) and DV in motion (Dm). The maximum error of the entire tracking volume for R, T, D and Dm was 9.9, 32.8, 37.9 and 37.2 mm, respectively. Limiting the tracking volume to 190 mm (from cranial to caudal) resulted in a maximum error of 4.0, 8.3, 8.5 and 8.9 mm, respectively. When used in the operation room, magnetic tracking shows high errors, mainly due to the operation table. The target area should be limited to increase accuracy, which is possible for most surgical applications. The use of the da Vinci(®) telemanipulator only slightly aggravates the distortion and can thus be used in combination with magnetic tracking systems.

Purpose: This study was designed to analyze the effect of two different ablation modes ("temperature control" and "power control") of a microwave system on procedural outcome in porcine kidneys in vivo., Methods: A commercially available microwave system (Avecure Microwave Generator; MedWaves, San Diego, CA) was used. The system offers the possibility to ablate with two different ablation modes: temperature control and power control. Thirty-two microwave ablations were performed in 16 kidneys of 8 pigs. In each animal, one kidney was ablated twice by applying temperature control (ablation duration set point at 60 s, ablation temperature set point at 96°C, automatic power set point; group I). The other kidney was ablated twice by applying power control (ablation duration set point at 60 s, ablation temperature set point at 96°C, ablation power set point at 24 W; group II). Procedural outcome was analyzed: (1) technical success (e.g., system failures, duration of the ablation cycle), and (2) ablation geometry (e.g., long axis diameter, short axis diameter, and circularity)., Results: System failures occurred in 0% in group I and 13% in group II. Duration of the ablation cycle was 60±0 s in group I and 102±21 s in group II. Long axis diameter was 20.3±4.6 mm in group I and 19.8±3.5 mm in group II (not significant (NS)). Short axis diameter was 10.3±2 mm in group I and 10.5±2.4 mm in group II (NS). Circularity was 0.5±0.1 in group I and 0.5±0.1 in group II (NS)., Conclusions: Microwave ablations performed with temperature control showed fewer system failures and were finished faster. Both ablation modes demonstrated no significant differences with respect to ablation geometry.

Purpose: To describe angiographic, macroscopic and microscopic features of super-micro-bland particle embolization in combination with RF-ablation in kidneys. Thereby, a special focus was given on the impact of the sequence of the different procedural steps., Materials and Methods: In ten pigs, super-micro-bland particle embolization combined with RF-ablation was carried out. Super-micro-bland embolization was performed with spherical particles of very small size and tight calibration (40 ± 10 μm). In the left kidneys, RF-ablations were performed before embolization (I). In the right kidneys, RF-ablations were performed after embolization (II). The animals were killed three hours after the procedures. Angiographic (e.g. vessel architecture), macroscopic (e.g. long and short axes of the RF-ablations) and microscopic (e.g. particle distribution) study goals were defined., Results: Angiography detected almost no vessels in the center of the RF-ablations in I. In II, angiography could not define the RF-ablations. Macroscopy detected significantly larger long and short axes of the RF-ablations in II compared to I (52.2 ± 3.2 mm vs. 45.3 ± 6.9 mm [P<0.05] and 25.1 ± 3.5mm vs. 20.0 ± 1.9 mm [P<0.01], respectively). Microscopy detected irregular particle distribution at the rim of the RF-ablations in I. In II, microscopy detected homogeneous particle distribution at the rim of the RF-ablations. Microscopy detected no particles in the center of the RF-ablations in I and II., Conclusion: The sequence of the different procedural steps of super-micro-bland particle embolization combined with RF-ablation impacts angiographic, macroscopic and microscopic features in kidneys in the acute setting., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: Robotic assistance is considered one innovation within abdominal surgery over the past decade that has the potential to compensate for the drawbacks of conventional laparoscopy, such as limited degree of freedom, 2D vision, fulcrum, and pivoting effect. Robotic systems provide corresponding solutions as 3D view, intuitive motion and enable additional degrees of freedom. This review provides an overview of the history of medical robotics, experimental studies, clinical state-of-the-art and economic impact., Methods: The Medline database was searched for the terms "robot, telemanipulat, and laparoscop." A total of 2,573 references were found. All references were considered for information on robotic assistance in advanced laparoscopy. Further references were obtained through cross-referencing the bibliography cited in each work., Results: In experimental studies, current robotic systems showed superior handling and ergonomics compared to conventional laparoscopic techniques. In gynecology especially for hysterectomy and in urology especially for prostatectomy, two procedures formerly performed via an open approach, the robot enables a laparoscopic approach. This results in reduced need for pain medication, less blood loss, and shorter hospital stay. Within abdominal surgery, clinical studies were generally unable to prove a benefit of the robot. While the benefit still remains open to discussion, robotic systems are spreading and are available worldwide in tertiary centers., Conclusion: Robotic assistance will remain an intensively discussed subject since clinical benefits for most procedures have not yet been proven. The most promising procedures are those in which the robot enables a laparoscopic approach where open surgery is usually required.

Aims: Different surgical transection methods have been used for distal pancreatectomy (DP), but none of them has yet achieved perfect results. This study compares 2 standard transection techniques with the alternative LigaSure technique., Methods: Forty-eight pigs underwent a DP. Sixteen animals were operated on with a scalpel followed by hand suturing. Sixteen pigs received a DP using an Endo GIA, and the pancreas of 16 pigs was transected with LigaSure. The transection surface of remnant pancreas was observed for liquid collection and abscess on postoperative day 7., Results: Operating time on the day of DP was significantly different, with a shorter operating time in the stapler and LigaSure groups. The morbidity on postoperative day 7 was similar in all groups., Conclusion: In the present experimental animal study, LigaSure seems to be fast and safe as well as comparable with the standard transection and closure techniques in DP.

Purpose: To determine the effect of tissue perfusion on microwave ablation lesions in an experimental in vivo study in porcine kidneys., Materials and Methods: Twelve kidneys of six pigs were studied. In each animal, two microwave ablations were created in one kidney without limitation of tissue perfusion (group 1). In the other kidney, two microwave ablations were performed with interruption of blood flow (group 2). All microwave ablations were performed with identical system parameters (eg, temperature control mode, ablation time of 80 s, and temperature of 110°C). The animals were euthanized 3 hours later. The kidneys were harvested and cut into 2-3-mm transverse slices. Microwave ablation zone dimensions (eg, length, width, and volume) and shape (eg, sphericity ratio) and corresponding variability were compared between groups., Results: Microwave ablation areas were significantly longer (41.6 mm ± 4.0 vs 34.2 mm ± 5.9; P < .01) and wider (16.6 mm ± 1.2 vs 12.2 mm ± 2.1; P < .001) in group 2 than in group 1. Similarly, microwave ablation volume was significantly greater in group 2 compared with group 1 (6.7 cm(3) ± 1.0 vs 3.3 cm(3) ± 1.2; P < .001). Ablation area shapes were similar between groups (sphericity ratio, 2.57 ± 0.42 vs 2.39 ± 0.34). Ablation area variabilities were also comparable between groups (volume variance of 1.32 vs 0.93; sphericity ratio variance of 0.18 vs 0.11)., Conclusions: After interruption of blood flow, microwave ablation areas are significantly larger than those achieved without limitation of tissue perfusion. Microwave ablation area shape and variability were comparable between study groups., (Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.)

The purpose of this study was to evaluate the effect of renal artery embolization with small and narrowly calibrated microparticles on the coagulation diameter, volume, and shape of radiofrequency ablations (RFAs) in porcine kidneys. Forty-eight RFAs were performed in 24 kidneys of 12 pigs. In 6 animals, bilateral renal artery embolization was performed with small and narrowly calibrated microparticles. Upper and lower kidney poles were ablated with identical system parameters. Applying three-dimensional segmentation software, RFAs were segmented on registered 2 mm-thin macroscopic slices. Length, depth, width, volume&#95;segmented, and volume&#95;calculated were determined to describe the size of the RFAs. To evaluate the shape of the RFAs, depth-to-width ratio (perfect symmetry-to-lesion length was indicated by a ratio of 1), sphericity ratio (perfect sphere was indicated by a sphericity ratio of 1), eccentricity (perfect sphere was indicated by an eccentricity of 0), and circularity (perfect circle was indicated by a circularity of 1) were determined. Embolized compared with nonembolized RFAs showed significantly greater depth (23.4 ± 3.6 vs. 17.2 ± 1.8 mm; p < 0.001) and width (20.1 ± 2.9 vs. 12.6 ± 3.7 mm; p < 0.001); significantly larger volume&#95;segmented (8.6 ± 3.2 vs. 3.0 ± 0.7 ml; p < 0.001) and volume&#95;calculated (8.4 ± 3.0 ml vs. 3.3 ± 1.1 ml; p < 0.001); significantly lower depth-to-width (1.17 ± 0.10 vs. 1.48 ± 0.44; p < 0.05), sphericity (1.55 ± 0.44 vs. 1.96 ± 0.43; p < 0.01), and eccentricity (0.84 ± 0.61 vs. 1.73 ± 0.91; p < 0.01) ratios; and significantly greater circularity (0.62 ± 0.14 vs. 0.45 ± 0.16; p < 0.01). Renal artery embolization with small and narrowly calibrated microparticles affected the coagulation diameter, volume, and shape of RFAs in porcine kidneys. Embolized RFAs were significantly larger and more spherical compared with nonembolized RFAs.

Noxious stimuli activate a complex cerebral network. During central sensitization to pain, activity in most of these areas is changed. One of these areas is the posterior parietal cortex (PPC). The role of the PPC during processing of acute pain as well as hyperalgesia and tactile allodynia remains elusive. Therefore, we performed a functional magnetic resonance imaging (fMRI) based, neuro-navigated, repetitive transcranial magnetic stimulation (rTMS) study in 10 healthy volunteers. Firstly, pin-prick hyperalgesia was provoked on the right volar forearm, using the model of electrically-induced secondary mechanical hyperalgesia. fMRI was performed during pin-prick stimulation inside and outside the hyperalgesic areas. Secondly, on four different experimental sessions, the left and right individual intraparietal BOLD peak-activations were used as targets for a sham-controlled 1 Hz rTMS paradigm of 10 min duration. We measured psychophysically the (i) electrical pain stimulus intensity on an 11-point numeric pain rating scale (NRS, 0-10), the (ii) area of hyperalgesia, and the (iii) area of dynamic mechanical allodynia. Sham stimulation or rTMS was performed 16 min after induction of pin-prick hyperalgesia and tactile allodynia. Compared to sham stimulation, no significant effect of rTMS was observed on pain stimulus intensity and the area of allodynia. However, a reduction of the hyperalgesic area was observed for rTMS of the left PPC (P<0.05). We discuss the role of the PPC in central sensitization to pain, in spatial discrimination of pain stimuli and in spatial-attention to pain stimuli., (Copyright 2010 IBRO. Published by Elsevier Ltd. All rights reserved.)

Background/purpose: To assess the feasibility of intravenous 64-multi-detector row computed tomography (CT)-cholangiography of porcine livers with definition of the temporal window for optimal bile duct delineation., Methods: Six healthy Landrace pigs, each weighing 28.97 +/- 2.99 kg, underwent 64-multi-detector row CT-cholangiography. Each pig was infused with 50 ml of meglumine iotroxate continuously over a period of 20 min and, starting with the initiation of the infusion, 18 consecutive CT scans of the abdomen at 2-min intervals were acquired. All series were evaluated for bile duct visualization scores and maximum bile duct diameters as primary study goals and bile duct attenuation and liver enhancement as secondary study goals., Results: Of the 16 analyzed biliary tract segments, maximum bile duct visualization scores ranged between 4.00 +/- 0.00 and 2.83 +/- 1.47. Time to maximum bile duct visualization scores ranged between 10 and 34 min. Average bile duct visualization scores for the 10- to 34-min interval ranged between 3.99 +/- 0.05 and 2.78 +/- 0.10. Maximum bile duct diameters ranged between 6.47 +/- 1.05 and 2.65 +/- 2.23 mm. Time to maximum bile duct diameters ranged between 24 and 34 min. Average bile duct diameters for the 10- to 34-min interval ranged between 6.00 +/- 0.38 and 2.40 +/- 0.13 mm., Conclusions: Intravenous 64-multi-detector row CT-cholangiography of non-diseased porcine liver is feasible, with the best bile duct delineation acquired between 10 and 34 min after initiation of the contrast agent infusion.

Neuropathic pain syndromes are characterised by the occurrence of spontaneous ongoing and stimulus-induced pain. Stimulus-induced pain (hyperalgesia and allodynia) may result from sensitisation processes in the peripheral (primary hyperalgesia) or central (secondary hyperalgesia) nervous system. The underlying pathophysiological mechanisms at the nociceptor itself and at spinal synapses have become better understood. However, the cerebral processing of hyperalgesia and allodynia is still controversially discussed. In recent years, neuroimaging methods (functional magnetic resonance imaging, fMRI; magnetoencephalography, MEG; positron emission tomography, PET) have provided new insights into the aberrant cerebral processing of neuropathic pain. The present paper reviews different cerebral mechanisms contributing to chronicity processes in neuropathic pain syndromes. These mechanisms include reorganisation of cortical somatotopic maps in sensory or motor areas (highly relevant for phantom limb pain and CRPS), increased activity in primary nociceptive areas, recruitment of new cortical areas usually not activated by nociceptive stimuli and aberrant activity in brain areas normally involved in descending inhibitory pain networks. Moreover, there is evidence from PET studies for changes of excitatory and inhibitory transmitter systems. Finally, advanced methods of structural brain imaging (voxel-based morphometry, VBM) show significant structural changes suggesting that chronic pain syndromes may be associated with neurodegeneration.

Knowledge about the pathophysiology underlying the complex regional pain syndrome (CRPS) has increased over the last years. Classically, CRPS has been considered to be mainly driven by sympathetic dysfunction with sympathetically maintained pain being its major pathogenetic mechanism. Currently, the disease is understood as result of a complex interplay between altered somatosensory, motor, autonomic and inflammatory systems. Peripheral and central sensitization is a common feature in CRPS as in other neuropathic pain syndromes. One important mechanism is the sensitization of spinal dorsal horn cells via activation of postsynaptic NMDA-receptors by chronic C-fiber input. Differential activity of endogenous pain modulating systems may play a pivotal role in the development of CRPS, too. Neuronal plasticity of the somatosensory cortex accounts for central sensory signs. Also the motor system is subject to central adaptive changes in patients with CRPS. Calcitonin-gene related peptide (CGRP) and substance P mediate neurogenic inflammation. Additionally other proinflammatory cytokines involved in the inflammatory response in CRPS have been identified. In terms of the sympathetic nervous system, recent evidence rather points to a sensitization of adrenergic receptors than to increased efferent sympathetic activity. Particularly the expression of alpha (1)-adrenoceptors on nociceptive C-fibers may play a major role. These pathophysiological ideas do not exclude each other. In fact they complement one another. The variety of the involved systems may explain the versatile clinical picture of CRPS., (Georg Thieme Verlag KG Stuttgart, New York.)

Background/aims: To determine whether intravenous morphine comedication improves bile duct visualization, diameter and/or volume applying intravenous CT cholangiography in a porcine liver model., Methods: 12 Landrace pigs underwent intravenous CT cholangiography. Eight minutes after initiation of the contrast material infusion, either morphine sulfate (n = 6 animals) or normal saline (n = 6 animals) was administered. Eighteen consecutive CT scans of the liver were acquired with 2-min intervals starting with initiation of the contrast material infusion. Maximum bile duct visualization scores, diameters and volumes and time to maximum bile duct visualization scores, diameters and volumes were determined., Results: Maximum bile duct visualization scores, diameters and volumes and time to maximum bile duct visualization scores, diameters and volumes were not significantly different when the morphine group was compared to the normal saline group. Maximum bile duct visualization scores ranged between 4.00 ± 0.00 and 2.83 ± 1.47. Maximum bile duct diameters ranged between 6.77 ± 0.40 and 2.10 ± 1.35 mm. Maximum bile duct volume was 16.41 ± 7.33 ml in the morphine group and 16.79 ± 5.65 ml in the normal saline group., Conclusion: Intravenous morphine comedication failed to improve bile duct visualization and to increase bile duct diameter and volume applying CT cholangiography., (Copyright © 2010 S. Karger AG, Basel.)

Background: Mesh reinforcement in hiatal hernia surgery is debated. Randomized controlled trials have shown that recurrences may be reduced, but there is also the fear of mesh-related complications. Experimental studies on the characteristics of specific mesh types with regard to the risk of such complications are rare. The current study aimed to investigate the properties of a circular heavy-weight polypropylene mesh in terms of stenosis, migration, erosions, and adhesions in a porcine model., Methods: A 55 x 55-mm heavy-weight polypropylene mesh with a 16.5-mm eccentric hole for the esophagus corresponding to a calculated mesh area of 2811 mm(2) and a hole area of 214 mm(2) were implanted in nine German Landrace pigs. Six weeks later, the meshes were explanted and investigated for size, shrinkage, migration and adhesions., Results: The total mesh area shrank to a mean of 2,040 +/- 178 mm(2) (p < 0.001), and the hole for the esophagus showed a trend toward an increase to 239 +/- 38 mm(2) (p = 0.108). In not a single location did the mesh overhang the hiatal margin. The mean distance of retraction from the hiatal margin was 4.3 +/- 2.8 mm. Therefore, no stenoses, migrations, or erosions occurred., Conclusions: A circular heavy-weight polypropylene mesh seems to be appropriate for the application at the esophageal hiatus in terms of safety and stability. This means that it is characterized by a position-stable centered fixation around the esophagus without a tendency toward stenosis, migration, or erosion.

Background and Purpose: The cardioprotective effects of delta-opioid receptor agonists is mediated-at least in part-via oxygen radicals. Mannitol that is used in cardiac surgery because of its osmotic properties exerts its beneficial effects on stunned myocardium via scavenging hydroxyl radicals. The effects of a delta-opioid receptor agonist (D-Ala2-D-Leu5-Enkephalin [DADLE]), the radical scavenger mannitol and their combination on postischemic dysfunction in rabbit hearts were investigated., Methods: Isolated, blood-perfused rabbit hearts were subjected to a 20-min global, normothermic, no-flow ischemia that was followed by a 60-min reperfusion. Systolic and diastolic ventricular function as well as coronary blood flow (CBF) were assessed. The hearts were assigned to one of four groups: 1. placebo (n = 6); 2. DADLE (n = 8; 430 nM); 3. mannitol (n = 7; 8.6 mM); 4. DADLE + mannitol (n = 7)., Results: Ischemic contracture in the DADLE and the mannitol group was significantly smaller compared with the placebo group. Contracture was smallest in the DADLE + mannitol group. The postischemic function in the placebo group was drastically reduced (p < 0.05), while it was best preserved in the DADLE + mannitol group. CBF and MVO(2) were changed similarly in all groups (n. s.). The external efficiency was significantly higher in the groups with DADLE and/or mannitol than in the placebo group. Both DADLE and mannitol exhibit cardioprotective properties. Combination of both substances exerts an additive, positive effect on the ischemic contracture. Noteworthy, the protective effects of DADLE during reperfusion were not antagonized by the oxygen radical scavenger mannitol. On the other hand, DADLE + mannitol did not augment the protective effects of the single substances during reperfusion, except for the isovolumic LVP(max)., Conclusion: Both substances improve the postischemic systolic and diastolic function and the relation between cardiac work and oxygen needed for this work. Thus, both substances offer promising properties in the clinic.

The one-proton knockout channel from 6He (240 MeV/u) impinging on a carbon target has been investigated. The triton fragments originating from this channel were detected in coincidence with the two neutrons. A broad structure, peaked at 3 MeV above the t+2n threshold, is observed in the t+n+n-relative energy spectrum. It is shown that this structure is mainly due to a I(pi)=1/2(+) resonance as expected for the 5H ground state, and from the observed angular and energy correlations, being used for the first time in 5H studies, that the neutrons to a large extent occupy the p shell.

Low-lying resonance states in 7He(6He+n), formed after fragmentation reactions of a 227 MeV/nucleon 8He beam on a carbon target, have been studied. Coincidences between 6He nuclei and neutrons, corresponding to the one-neutron knockout channel in 8He, were selected. The relative energy spectrum in the 6He+n system shows a structure, which is interpreted as the 7He ( Ipi = 3/2(-)) ground state, unbound with 0.43(2) MeV relative to the 6He+n system and a width of Gamma = 0.15(8) MeV overlapping with an excited ( Ipi = 1/2(-)) state observed at 1.0(1) MeV with a width of Gamma = 0.75(8) MeV.

As a part of the physical-technical program of the heavy-ion therapy project at GSI we have investigated the nuclear fragmentation of high-energy ion beams delivered by the heavy-ion synchrotron SIS, using water as a tissue-equivalent target. For a direct comparison of fragmentation properties, beams of 10B, 12C, 14N, and 16O were produced simultaneously as secondary beams from a primary 18O beam and separated in flight by magnetic beam analysis. The Z-distributions of beam fragments produced in the water target were measured via energy loss in a large ionisation chamber and a scintillator telescope. From these data we obtained both total and partial charge-changing cross sections. In addition we have performed Bragg measurements using two parallel-plate ionization chambers and a water target of variable length. The detailed shape of the measured Bragg curves and the measured cross sections are in good agreement with model calculations based on semi-empirical formulae.

Samples of splash basin fluid were cultured at the end of 78 randomly selected orthopedic operations. Fifty-eight (74%) of the specimens were positive on culture. Staphylococcus epidermidis was the prevalent organism. Thirty-four (59%) of the positive cultures grew multiple organisms. Seven (12%) grew more than 100 colonies per 100 ml specimen. This study demonstrates that splash basin fluid is frequently contaminated and may be a source of wound contamination during orthopedic surgery. Implants should not be placed in the splash basin, and instruments placed in it should not be returned to the operative wound.

In this descriptive epidemiologic study, prevalence rates of hepatitis B surface antigen (HBsAg) and its antibody (anti-HBs) among fourth-year dental students and second-year dental hygiene students were found to be comparable to those of a control population and a local age-adjusted blood donor group. This observation contrasts with the rates reported for practicing dentists, especially oral surgeons, and indicates that the increased risk experienced by dentists after dental school may be attributable to potentially greater exposure to the hepatitis B virus resulting from an expanded patient load. No significant correlation was found between a positive serologic response and several potential risk factors: previous liver disease, prior contact with hepatitis patients, parenteral injections, facial hair, and punctures sustained during dental procedures. In contrast, prevalence of HBsAg and anti-HBs was increased significantly among black students.