Enzymatic activity of extracellular circulating proteasome in the CSF of patients with malignant Intrinsic and metastatic brain tumors: proof of concept.

BACKGROUND: Malignant intrinsic brain tumors are a hazardous disease with limited life expectancy despite intensive research in new targeted treatment options. Lately, proteasome inhibitors have been identified as potent agents causing death in glioma cell lines. It is the aim of the present study to identify proteasomal activity in the CSF of patients suffering from malignant brain tumors. METHODS: A total of 24 patients with histological confirmed brain tumors (12 malignant gliomas, 12 metastases) were included and CSF probes preoperatively analyzed for concentration and enzymatic activity of free circulating proteasome. Tumor volumina were assessed using the preoperative MRI and correlated with the CSF findings. Statistical analyses were performed using SPSS (18.0.3; SPSS Inc., Chicago, IL, USA). RESULTS: Extracellular proteasomes were found in all CSF samples showing enzymatic activity. Proteasome concentrations (28 ng/mL and 23 ng/mL, resp.) were elevated compared to a historical control group. Proteasomal enzymatic chymotrypsin-like activity was significantly raised in patients with gliomas (mean 31 fkat/ mL) compared to controls (P<0.049), whereas the enzymatic activity was not significantly elevated in metastases (P=0.109). In gliomas, neither concentration nor enzymatic activity correlated with the preoperative assessed tumor volume. CONCLUSIONS: This pilot study clearly showed that the proteasomal activity in the CSF is significantly elevated in patients with intrinsic brain tumors. Further studies need to identify the proteasomal concentration and enzymatic activity as a potential biomarker for the effectiveness of any treatment and for the early diagnosis of a possible recurrence of the disease.

Coffee break has no impact on laparoscopic skills: a randomized double-blinded placebo-controlled parallel-group trial.

BACKGROUND: Coffee is a widely consumed beverage. Surgeons often drink coffee before performing surgery. Caffeine intake leads to tremor which might have a negative effect on surgeons' fine motor skills. METHODS: A double-blinded parallel-group trial was conducted in order to investigate if caffeinated coffee intake has a negative effect on laparoscopic skills and increases tremor, regardless of previous coffee consumption. 118 participants were selected during a congress of the German Society of Surgery. Exclusion criteria were immaturity and no given consent. Participants and investigators were blinded. Participants were randomized with a 1:1 allocation into interventional group receiving caffeinated coffee or placebo group receiving decaffeinated coffee. The motor skills were tested with two validated laparoscopic exercises at a laparoscopy simulator (LapSim®) before and 30 min after coffee intake. Data on influencing factors were recorded in a standardized questionnaire and tested for equal distribution in both groups. In both exercises four parameters were recorded: left and right hand path length and angular path. Their differences and the resulting effect scores were calculated for both groups as primary outcome to test which group showed greater improvement on the second round of exercises. Registration number DRKS00023608, registered retrospectively. RESULTS: Fifty nine subjects were assigned to each the interventional (54 analyzed) and placebo group (53 analyzed) with 11 drop outs. There was no significant difference between the placebo and interventional group in the two exercises in effect score 30 min after coffee intake [mean (SD); 38.58 (10.66) vs. 41.73 (7.40) and 113.09 (28.94) vs. 116.59 (25.63)]. A significant improvement from first to second measurement in the first exercise could be observed for both groups, demonstrating the training effect. CONCLUSION: In our study, we verified that additional caffeinated coffee intake, e.g., during a coffee break, does not lead to deterioration of laparoscopic fine motor skills.

Reduced neutrophil elastase inhibitor elafin and elevated transforming growth factor-ß1 are linked to inflammatory response in sputum of cystic fibrosis patients with Pseudomonas aeruginosa.

RESEARCH QUESTION: Pulmonary disease progression in patients with cystic fibrosis (CF) is characterised by inflammation and fibrosis and aggravated by Pseudomonas aeruginosa (Pa). We investigated the impact of Pa specifically on: 1) protease/antiprotease balance; 2) inflammation; and 3) the link of both parameters to clinical parameters of CF patients. METHODS: Transforming growth factor-ß1 (TGF-ß1), interleukin (IL)-1ß, IL-8, neutrophil elastase (NE) and elastase inhibitor elafin were measured (ELISA assays), and gene expression of the NF-κB pathway was assessed (reverse transcriptase PCR) in the sputum of 60 CF patients with a minimum age of 5 years. Spirometry was assessed according to American Thoracic Society guidelines. RESULTS: Our results demonstrated the following: 1) NE was markedly increased in Pa-positive sputum, whereas elafin was significantly decreased; 2) increased IL-1ß/IL-8 levels were associated with both Pa infection and reduced forced expiratory volume in 1 s, and sputum TGF-ß1 was elevated in Pa-infected CF patients and linked to an impaired lung function; and 3) gene expression of NF-κB signalling components was increased in sputum of Pa-infected patients, and these findings were positively correlated with IL-8. CONCLUSION: Our study links Pa infection to an imbalance of NE and NE inhibitor elafin and increased inflammatory mediators. Moreover, our data demonstrate an association between high TGF-ß1 sputum levels and a progress in chronic lung inflammation and pulmonary fibrosis in CF. Controlling the excessive airway inflammation by inhibition of NE and TGF-ß1 might be promising therapeutic strategies in future CF therapy and a possible complement to cystic fibrosis transmembrane conductance regulator (CFTR) modulators.

Effect of Lumacaftor/Ivacaftor on glucose metabolism and insulin secretion in Phe508del homozygous cystic fibrosis patients.

OBJECTIVE: To investigate the effect of Lumacaftor/Ivacaftor on glucose metabolism and insulin secretion in patients with cystic fibrosis (CF) (Phe508del/Phe508del). METHODS: A standard oral glucose tolerance test (OGTT) and an intravenous glucose tolerance test (IVGTT) were performed to investigate glucose metabolism and insulin secretion before and after 6-8weeks of treatment with Lumacaftor/Ivacaftor in 5 Phe508del-homozygous CF patients. The area under the curve (AUC) for glucose and insulin levels was calculated using the trapezoidal approximation. RESULTS: 5 participants were investigated. Treatment with Lumacaftor/Ivacaftor was followed by an improvement of the 2h glucose levels in 3 patients and worsening in 2 patients. Analysis of the time course of blood glucose levels during OGTT revealed an increase of the AUC in 3 of 5 patients. In response to IVGTT, acute insulin secretion improved in 2 patients and worsened in 3. CONCLUSION: The investigation could not demonstrate that treatment with Lumacaftor/Ivacaftor had a consistent impact on glucose tolerance and insulin secretion. Further adequately-powered studies examining glucose metabolism are needed to properly evaluate drug response in the endocrine pancreas and to test whether this treatment could eventually prevent the development of cystic fibrosis-related diabetes (CFRD).

Circulating extracellular proteasome in the cerebrospinal fluid: a study on concentration and proteolytic activity.

Alterations of the intracellular ubiquitin-proteasome pathway are found in neurodegenerative and inflammatory disorders of the central nervous system, as well as in its malignancies. Inhibitory substrates of the proteasomes represent promising approaches to control autoimmune inflammations and induction of apoptosis in cancer cells. Extracellular circulating proteasomes are positively correlated to outcome prognosis in hematogenic neoplasias and the outcome in critically ill patients. Previously, we reported raised levels of proteolytic active 20S proteasomes in the extracellular alveolar space in patients with acute respiratory distress syndrome (ARDS). For the cerebrospinal fluid, we assumed that extracellular circulating proteasomes with enzymatic activity can be found, too. Cerebrospinal fluid (CSF) samples of twenty-six patients (14 females, 12 males), who underwent diagnostic spinal myelography, were analyzed for leukocyte cell count, total protein content, lactate and interleukine-6 (Il-6) concentrations. CSF samples were analyzed for concentration and enzymatic activity of extracellular 20S proteasomes (fluorescenic substrate cleavage; femtokatal). Blood samples were analyzed with respect to concentration of extracellular circulating proteasomes. Choroidal plexus was harvested at autopsies and examined with immunoelectron microscopy (EM) for identification of possible transportation mechanisms. Statistical analysis was performed using SPSS (18.0.3). In all patients, extracellular proteasome was found in the CSF. The mean concentration was 24.6 ng/ml. Enzymatic activity of the 20S subunits of proteasomes was positively identified by the fluorescenic subtrate cleavage at a mean of 8.5 fkat/ml. Concentrations of extracellular proteasomes in the CSF, total protein content and Il-6 were uncorrelated. Immunoelectron microscopy revealed merging vesicles of proteasomes with the outer cell membrane suggestive of an exozytic transport mechanism. For the first time, extracellular circulating 20S proteasome in the CSF of healthy individuals is identified and its enzymatic activity detected. A possible exozytic vesicle-bond transportation mechanism is suggested by immunoelectron microscopy. The present study raises more questions on the function of extracellular proteasome in the CSF and encourages further studies on the role of extracellular protesomes in pathological conditions of the central nervous system (tumor lesions and inflammatory processes).

A tutorial platform suitable for surgical simulator training (SimMentor).

BACKGROUND: The introduction of simulators in surgical training entails the need to develop pedagogic platforms adapted to the potentials and limitations provided by the information technology. As a solution to the technical challenges in treating all possible interaction events and to obtain a suitable pedagogic approach, we have developed a pedagogic platform for surgical training, SimMentor. METHODS: In SimMentor the procedure to be practiced is divided into a number of natural phases. The trainee will practice on one phase at a time, however he can select the sequence of phases arbitrarily. A phase is taught by letting the trainee alternate freely between 2 modes: 1: A 3-dimensional animated guidance designed for learning the objectives and challenges in a procedure. 2: An interactive training session through the instrument manipulator device designed for training motoric responses based on visual and tactile responses produced by the simulator. The two modes are interfaced with the same virtual reality platform, thus SimMentor allows a seamless transition between the modes. RESULTS: We have developed a prototype simulator for robotic assisted endoscopic CABG (Coronary Artery Bypass Grafting) procedure by first focusing on the anastomosis part of the operation. Tissue, suture and instrument models have been developed and integrated with a simulated model of a beating heart comprises the elements in the simulator engine that is used in construction a training platform for learning different methods for performing a coronary anastomosis procedure. CONCLUSION: The platform is designed for integrating the following features: 1) practical approach to handle interactivity events with flexible-objects 3D simulators, 2) methods for quantitative evaluations of performance, 3) didactic presentations, 4) effective ways of producing diversity of clinical and pathological training scenarios.