Einfluss von HLA-G1s auf die Proliferation und Zytotoxizität von NK92-Zellen und NK-Zellen

In der vorliegenden Arbeit wurden die Zellen der Natürlichen Killerzelllinie 92 (NK92-Zelllinie) und Natürliche Killerzellen des peripheren Blutes (Blut-NK-Zellen) unter dem Einfluss von Human Leukocyte Antigene G1 soluble (HLA-G1s) in verschiedenen Konzentrationen (0,2µg/ml-2,0µg/ml) auf ihre Proliferationsaktivität zu verschiedenen Zeitpunkten (24, 48 und 72 Stunden nach Versuchsbeginn) und Zytotoxizität gegenüber der K562-Zelllinie untersucht. Es sollte geprüft werden, inwieweit HLA-G1s die Proliferation und Zytotoxizität der NK-Zellen moduliert

Automatically Welded Tubular X‐Joints for Jacket Substructures: Prediction of the Technical Fatigue Crack Location

To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented

Neuroendoscopic surgery in neonates — indication and results over a 10-year practice

Purpose: Neuroendoscopic procedures for treatment of term and preterm newborn infants, such as endoscopic lavage for posthemorrhagic hydrocephalus, are gaining popularity despite sparse data. This single-institution report compiles all neuroendoscopic surgical procedures performed in neonates during a 10-year period. Methods: Charts and electronic records were reviewed of all consecutive newborns who underwent a neuroendoscopic procedure before reaching a postmenstrual age of 44 weeks between 09/2010 and 09/2020. Available documentation was reviewed regarding the performed neuroendoscopic procedure, course of disease, complications, and all re-operations throughout the first year of life. Results: During the 10-year study period, 116 infants (median gestational age at birth: 29 (1)/7 weeks) underwent a total of 153 neuroendoscopic procedures (median postmenstrual age at surgery: 35 (0)/7 weeks). The most common indication at the time of the neuroendoscopic procedures (n = 153) was intraventricular hemorrhage (IVH, n = 119), intraventricular infection (n = 15), congenital malformation (n = 8), isolated 4th ventricle (n = 7), multiloculated hydrocephalus (n = 3), and tumor (n = 1). Thirty-eight of 116 children (32.8%) underwent 43 operative revisions after 153 neuroendoscopic procedure (28.1%). Observed complications requiring surgical revision were secondary infection (n = 11), CSF fistula (n = 9), shunt dysfunction (n = 8), failure of ETV (n = 6), among others. 72 children (62%) of 116 children required permanent CSF diversion via a shunt. The respective shunt rates per diagnosis were 47 of 80 (58.8%) for previously untreated IVH, 11 of 13 (84.6%) for intraventricular infection. Shunt survival rate for the first year of life was 74% for the whole cohort. Conclusion: The experience with this large cohort of neonates demonstrates the feasibility of neuroendoscopic technique for the treatment of posthemorrhagic or postinfectious hydrocephalus. Rate and type of complications after neuroendoscopic procedures were within the expected range. Assessing the potential long-term benefits of neuroendoscopic techniques has to await results of ongoing studies

First experience with augmented reality neuronavigation in endoscopic assisted midline skull base pathologies in children

Introduction: Endoscopic skull base approaches are broadly used in modern neurosurgery. The support of neuronavigation can help to effectively target the lesion avoiding complications. In children, endoscopic-assisted skull base surgery in combination with navigation systems becomes even more important because of the morphological variability and rare diseases affecting the sellar and parasellar regions. This paper aims to analyze our first experience on augmented reality navigation in endoscopic skull base surgery in a pediatric case series. Patients and methods: A retrospective review identified seventeen endoscopic-assisted endonasal or transoral procedures performed in an interdisciplinary setting in a period between October 2011 and May 2020. In all the cases, the surgical target was a lesion in the sellar or parasellar region. Clinical conditions, MRI appearance, intraoperative conditions, postoperative MRI, possible complications, and outcomes were analyzed. Results: The mean age of our patients was 14.5 ± 2.4 years. The diagnosis varied, but craniopharyngiomas (31.2%) were mostly represented. AR navigation was experienced to be very helpful for effectively targeting the lesion and defining the intraoperative extension of the pathology. In 65% of the oncologic cases, a radical removal was proven in postoperative MRI. The mean follow-up was 89 +/- 79 months. There were no deaths in our series. No long-term complications were registered; two cerebrospinal fluid (CSF) fistulas and a secondary abscess required further surgery. Conclusion: The implementation of augmented reality to endoscopic-assisted neuronavigated procedures within the skull base was feasible and did provide relevant information directly in the endoscopic field of view and was experienced to be useful in the pediatric cases, where anatomical variability and rarity of the pathologies make surgery more challenging

Single molecule investigation of the onset and minimum size of the calcium-mediated junction zone in alginate

One of the principal roles of alginate, both natively and in commercial applications, is gelation via Ca2+-mediated crosslinks between blocks of guluronic acid. In this work, single molecule measurements were carried out between well-characterised series of nearly monodisperse guluronic acid blocks (‘oligoGs’) using dynamic force spectroscopy. The measurements provide evidence that for interaction times on the order of tens of milliseconds the maximum crosslink strength is achieved by pairs of oligoGs long enough to allow the coordination of 4 Ca2+ ions, with both shorter and longer oligomers forming weaker links. Extending the interaction time from tens to hundreds of milliseconds allows longer oligoGs to achieve much stronger crosslinks but does not change the strength of individual links between shorter oligoGs. These results are considered in light of extant models for the onset of cooperative crosslinking in polyelectrolytes and an anisotropic distribution of oligoGs on interacting surfaces and provide a timescale for the formation and relaxation of alginate gels at the single crosslink level

Guided Application of Ventricular Catheters (GAVCA) - multicentre study to compare the ventricular catheter position after use of a catheter guide versus freehand application: study protocol for a randomised trail

BACKGROUND: The standard technique for the placement of ventricular catheters (VC) comprises a high proportion of malpositioning of the catheter (12.5 to 40%). Technical advances such as neuronavigation or ultrasound have been shown to increase the accuracy of the procedure. Since these means result in significant technical and time consuming efforts, they are used for selected cases only. In order to simplify the controlled placement of ventricular catheters a newly developed smartphone assisted guiding tool has been introduced. In this study the efficacy and safety of this guiding tool is determined. METHODS/DESIGN: This study is a multicentre, randomised, controlled trial. A total of 144 patients planned for an elective shunting procedure will be enrolled throughout 10 study centres within two years. The primary objective of the trial is to show the superiority of the guided placement in comparison to the standard freehand technique of ventricular catheter application. Patients will be followed up for 30 days after the operation in regard to image-based evaluation of the catheter position as well as possible shunt dysfunction and complications. DISCUSSION: The Guided Application of Ventricular Catheters (GAVCA) trial compares the guided catheter positioning with the standard freehand technique of catheter placement in hydrocephalic patients. If superiority is shown, the standard technique may be changed with the advantage of a more reliable and safer positioning of the ventricular catheter with just a slight effort in time and pre-operative planning. TRIAL REGISTRATION: The GAVCA trial is registered at ClinicalTrials.gov under the number NCT01811589

Single center experiences with telemetric intracranial pressure measurements in patients with CSF circulation disturbances

Background: Hydrocephalus may present with heterogeneous signs and symptoms. The indication for its treatment and the optimal drainage in complex cases may be challenging. Telemetric intracranial pressure measurements (TICPM) may open new perspectives for those circumstances. We report our experiences using the Neurovent-P-tel and the Sensor Reservoir in a retrospective study. Methods: A series of 21 patients (age range 10–39.5 years) treated in our Pediatric Neurosurgical Unit receiving a TICPM was analyzed. In 8 patients, a Neurovent-P-Tel was implanted; 13 patients received a Sensor Reservoir, 6 of which as a stand-alone implant, while 7 were already shunted. TICPM were performed on an outpatient basis. Possible complications, follow-up surgeries, and TICPM were analyzed. Results: Concerning the complications, one infection was seen in each group and one postoperative seizure was observed in the P-tel group. TICPM-assisted shunt adjustments lead to clinical improvements in six patients in the P-tel group and six patients in the Sensor Reservoir group. In four out of six non-shunted patients, TICPM contributed to the indication toward shunt implantation. Conclusions: TICPM seems to be a promising tool to improve clinical management of shunted patients with complex hydrocephalus. The two available systems will need further technical improvements, concerning implantation time, measurements, and data analysis in order to optimize handling and interpretation of the data

Neuroendoscopic surgery in neonates — indication and results over a 10-year practice

Purpose!#!Neuroendoscopic procedures for treatment of term and preterm newborn infants, such as endoscopic lavage for posthemorrhagic hydrocephalus, are gaining popularity despite sparse data. This single-institution report compiles all neuroendoscopic surgical procedures performed in neonates during a 10-year period.!##!Methods!#!Charts and electronic records were reviewed of all consecutive newborns who underwent a neuroendoscopic procedure before reaching a postmenstrual age of 44 weeks between 09/2010 and 09/2020. Available documentation was reviewed regarding the performed neuroendoscopic procedure, course of disease, complications, and all re-operations throughout the first year of life.!##!Results!#!During the 10-year study period, 116 infants (median gestational age at birth: 29 !##!Conclusion!#!The experience with this large cohort of neonates demonstrates the feasibility of neuroendoscopic technique for the treatment of posthemorrhagic or postinfectious hydrocephalus. Rate and type of complications after neuroendoscopic procedures were within the expected range. Assessing the potential long-term benefits of neuroendoscopic techniques has to await results of ongoing studies