Manuel Braun

Temperature sensitivity of suicidal erythrocyte death.

Eur J Clin Invest 2010; 40 (6): 534–540

Endothelin B receptor stimulation inhibits suicidal erythrocyte death

Endothelins (ETs), potent endothelium‐derived mediators, stimulate formation of nitric oxide, which, in turn, protects against suicidal erythrocyte death or eryptosis, characterized by phosphatidylserine exposure at the erythrocyte surface and triggered by increase in cytosolic Ca2+ ([Ca2+]i). The present study explored whether the ET1‐receptor ETB influences suicidal erythrocyte death. To this end, [Ca2+]i (Fluo3‐fluorescence) and phosphatidylserine exposure (annexin V‐binding) were determined utilizing FACS analysis. Energy depletion increased [Ca2+]i and phosphatidylserine‐exposure, effects significantly blunted by ET1 (IC50 ≈ 100 nM) and the ETB receptor‐agonist sarafotoxin 6c (IC50 ≈ =T0 nM) but not by ET2 and ET3. ET1 and sarafotoxin significantly delayed the kinetics of suicidal erythrocyte death following energy depletion. ETB stimulation did not blunt the effect of Ca2+‐ionophore ionomycin (1 µM) on phosphatidylserine exposure. The in vivo significance was tested using rescued ETB‐knockout (etb−/−) and wild‐type (etb+/+) mice. The number of phosphatidylserine‐exposing erythrocytes, of reticulocytes and spleen size were significantly larger in etb−/− mice than in etb+/+‐mice. The etb−/− erythrocytes were more susceptible to the eryptotic effect of oxidative stress and more rapidly cleared from circulating blood than etb+/+ erythrocytes. Finally, the spleens from etb−/− mice were enlarged and contained markedly more phosphatidylserine‐exposing erythrocytes than spleens from etb+/+ mice. The observations disclose a novel function of ET1, i.e., protection from suicidal erythrocyte death.— Foller, M., Mahmud, H., Qadri, S. M., Gu, S., Braun, M., Bobbala, D., Hocher, B., Lang, F. Endothelin B receptor stimulation inhibits suicidal erythrocyte death. FASEB J. 24, 3351–3359 (2010). www.fasebj.org

Traditional Ideology as an Inhibitor of Sexual Behavior

Abstract The political and religious correlates of sexual behavior in a sample of 344 German university students are presented and discussed within a framework of traditional ideology stifling sexual choice and expression. More-intense religious belief was found to be associated with fewer or no sex partners, with diminished likelihood of oral sex experience, with less frequent masturbation (in women), and with less ability to imagine having homosexual relations (among women who had no history of homosexual activity). Left-wing political views were associated with oral sex experience (in men), more sexual partners (in women), the conceivability of having homosexual relations (among both men and women with no history of homosexual activity), having had homosexual experiences (in women), higher frequency of masturbation, and younger age at first intercourse (for women). Intensity of political interest, regardless of direction, was associated with greater reliability of womens orgasm during sex with a partn...

A teleoperated platform for transanal single-port surgery: Ergonomics and workspace aspects

We present a new teleoperation setup for minimally invasive single-port surgery through natural orifices. The system consists of an intra-corporal parallel slave robot with two instrument arms and a corresponding master interface with four degrees of freedom and grasping. The master interface mimicks the slave robot kinematics to prevent non-achievable movements. With a workspace of ⊘ 60 mm × 85 mm, interaction forces of up to 5 N and mean speeds of up to 327 mm/s the robot is designed to perform a rectum resection intervention, an operation hardly possible with conventional laparoscopic instruments. In this work, we address several ergonomic aspects of the setup, including surgeons pose, movement scaling, visual feedback, and haptic feedback. Two experiments were performed to investigate the accuracy and dexterity of the robotic system compared to conventional single-port systems. We found a significant decrease of errors in a point-and-touch-task when using the robot, but no effect on the duration of the task. Surgeons were able to perform suturing and knotting tasks as well as a gall bladder extraction in a porcine model with the robot in an hands on experiment. These experiments showed a good intuitivity and a high instrument control precision as described by the participants.

How Much Stereoscopic Effect Does Laparoscopy Need? Controlled, Prospective Randomized Trial on Surgical Task Efficiency in Standardized Phantom Tasks

Background. To regain 2-eyed vision in laparoscopy, dual-channeled optics have been introduced. With this optics design, the distance between the 2 front lenses defines how much stereoscopic effect is seen. This study quantifies the impact of an enhanced and a reduced stereo effect on surgical task efficiency. Methods. A prospective single-blinded study was performed with 20 laparoscopic novices in an inanimate experimental setting. A standard bichannelled stereo system was used to perform a suturing and knotting task. The working distance and the task size were scaled to vary the stereo effect and, thereby, simulate hypothetic stereo optics with enhanced and reduced optical bases. The task performances were timed, and the number of trials for stitching out was counted. The participants finally filled out a questionnaire to collect subjective impressions. Results. The increase of the stereo effect by 50% caused no objective improvement in laparoscopic knotting compared with typical 3D (control group with stereo basis of 4.5 mm). But ergonomic disadvantages (headache) were subjectively reported in 1 of 20 cases in the questionnaire. The reduction of the stereo effect by one-third led to a significantly longer average execution time. There was no significant dependence found between stereo effect and number of stich-out trials, stitching precision, or knotting quality. Conclusions. Considering laparoscopy, it does not seem advisable to enhance the stereo effect because of ergonomic problems. Otherwise, a miniaturization of the 3D scope (5 mm version) is problematic because its benefit mostly shrinks with the reduced stereo effect.

Fall 17: Morbus Crohn – eine Privatvorlesung

Die nachste Patientin in der Notaufnahme ist die 22-jahrige Jessica Maier, die sich mit seit zwei Wochen persistierendem Durchfall vorstellt. Sie berichtet weiterhin, dass sie 10- bis 15-mal am Tag auf die Toilette musse und dabei schwere Krampfe erlebe. Eine ahnliche Episode habe sie vor etwa einem halben Jahr schon mal erlitten, damals jedoch weniger heftig. Es sei dann irgendwie von selber wieder abgeklungen. Uber Ubelkeit oder Erbrechen klagt die junge Frau nicht. Und sie habe auch nie Fieber. Im Ausland sei sie seit 2 Jahren nicht mehr gewesen, und Antibiotika nehme sie eigentlich nie. Die vielen Stuhlentleerungen seien wirklich kraftraubend und wurden sie sehr belasten. Der Gewichtsverlust betrage allein in den letzten zwei Wochen 5 kg. Aktuell sei der Stuhlgang sogar manchmal leicht blutig und wirklich fast flussig. Heute sei sie zu Hause auf der Toilette fast kollabiert, sie sei echt am Ende ihrer Krafte.

Factors predicting hypocalcemia after total thyroidectomy – A retrospective cohort analysis

BACKGROUND Hypocalcemia after total thyroidectomy is the most frequent complication resulting in prolongation of hospitalisation. Therefore we aimed to analyse clinical risk factors predictive for hypocalcemia and its long term persistence after total thyroidectomy. METHODS Retrospective analysis of patients undergoing total thyroidectomy from 2005 until 2013. Outcome measures were initial postoperative hypocalcemia defined as serum calcium below 2.0 mmol/l after total thyroidectomy within 48 h and persistent hypocalcemia defined as serum calcium below 2.0 mmol/l above six months and/or the need for additional calcium and vitamin D supplementation. RESULTS Initial postoperative hypocalcemia was present in 160 of 702 patients (22.8%) with 91 patients (13%) developing symptoms. 48 patients (6.8%) had a persistent hypocalcemia above six months. Patients with an initial symptomatic postoperative hypocalcemia showed significantly more often a persistent hypocalcemia compared to asymptomatic patients with biochemical hypocalcemia (38 patients (41.8%) vs. 10 patients (14.5%), p < 0,001). In the binary logistic regression analysis, female gender (OR 2.4; CI95% 1.5-3.8), prolonged surgery time >189 min (OR 1.8; CI95% 1.2-2.6) and parathyroid reimplantation (OR 2.4; CI95% 1.2-4.7) were associated with initial hypocalcemia while only initial symptomatic hypocalcaemia was shown to be independently associated with persistent hypocalcemia (OR 40.9; CI95% 18.5-90.4). CONCLUSION Prolonged surgery time seems to correlate with initial postoperative hypocalcemia independently of the underlying disease and surgical expertise but does not affect the persistence of hypocalcemia. Initial symptomatic postoperative hypocalcemia after total thyroidectomy is associated with a high rate of persistent hypocalcemia.