Scientific publications of the Saarland University
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Assessment of the biofilm formation capacities of Staphylococcus aureus strains Newman and Newman D2C in vitro and in vivo
Get PDFStaphylococcus aureus is a major cause of implant-associated infections (IAIs). The ability of this
Gram-positive bacterium to cause IAIs is closely related to its capacity to attach to and to form biofilms
on the implant material. Biofilm formation of S. aureus on artificial surfaces is usually mimicked in
the laboratory by simple microplate-based in vitro assays and often involves type culture collection
preserved laboratory strains such as SA113 (ATCC 35556), Newman (NCTC 8178), and Newman D2C
(NCTC 10833, ATCC 25904). The latter two strains are phylogenetically closely related and often
inadvertently indicated as strain “Newman” in publications, albeit of the fact that strain Newman D2C
harbors among others mutations in the global regulatory loci agr and sae, which strongly impact the
phenotypic behavior of this strain. Wondering how the genetic differences between strains Newman
and Newman D2C alter the biofilm formation capacities of these two strains in vitro and in vivo, we
tested here the adhesion behavior and biofilm formation capacities of both strains on different kinds of
artificial surfaces (tissue culture-treated bottoms of 96-well polystyrene microplates and polyurethane based peripheral venous catheter [PVC] tubing). Additionally, we determined their ability to cause
infection in a foreign body-related murine infection model. Our studies revealed that the Newman and
Newman D2C derivatives kept at Saarland University, Germany, differ significantly in their abilities to
attach to microplate well bottoms and PVC tubing, and to form biofilms in various static and dynamic
in vitro assays. However, when the biofilm formation capacities of both strains were determined in
an in vivo infection model, rather comparable bacterial loads were observed. These findings suggest
that biofilm formation capacities of S. aureus strains may differ substantially in vitro and in vivo.
Additionally, researchers working with strains Newman and Newman D2C should be aware that both
strains differ substantially in their phenotypic behavior, and that both strains should be indicated
correctly to allow for a better comparison of data obtained with these strains in different laboratories
ZVK-Anlage in die linke Vena subclavia mittels Ultraschall-gesteuerter in-plane Punktion mit einem Mikrokonvex-Schallkopf versus Landmarkentechnik : eine randomisierte klinische Studie
Get PDFEinführung: Die Anlage von zentralen Venenkathetern ist eines der häufigsten invasiven Verfahren auf Intensivstationen. Für die Punktion der Vena subclavia (VSC) gibt es im Vergleich zur Vena jugularis interna keine eindeutige Empfehlung einer Ultraschall-gesteuerten ZVK-Anlage. Dies könnte an der Form des für Gefäßpunktionen üblicherweise verwendeten Linearschallkopfes liegen. Unsere Hypothese ist, dass die Effektivität und Sicherheit der ZVK-Anlage in die VSC mit einem Mikrokonvexschallkopf mit der ‚Mikrokonvex In-Plane Subclavian Puncture‘-Technik (MISP-Technik) im Vergleich zu der standardmäßig verwendeten Landmarken-Technik ‚Landmark Unsteril Prescan‘-Technik (LUP-Technik) verbessert werden kann. Methoden: Nach positivem Ethikvotum (Ethikkommission der Ärztekammer des Saarlandes, HA 08/21) wurden 101 Patienten, die sich einer allgemeinchirurgischen Operation am Uniklinikum des Saarlandes unterzogen, in die Studiengruppen randomisiert. Als Hauptzielgröße wurde a priori ein Risikoscore festgelegt. Dieser umfasst acht Unterpunkte: Anzahl der Punktionsversuche, Punktionsdauer (beinhaltet die Zeiten: Punktion bis zur Blutaspiration, Drahtvorschub und Dilatation bis alle ZVK-Schenkel aspirabel sind), arterielle Fehlpunktion, Hämatombildung, Venenhinterwand-Verletzung, Pneumothorax, Hämatothorax und Katheterfehllage. Bei Punktions-Abbrüchen wurde die Score-Maximalpunkzahl der jeweiligen Gruppe vergeben. Nebenzielgrößen waren Erfolgsrate (primär sowie insgesamt nach Methoden-Crossover), einzelne Komplikationen und Zeiten, der Punktionsort, unmittelbar erfolgreiche Punktionen, Anzahl der Drahtvorschübe und ein subjektiver Sicherheitsscore mit sechs Unterpunkten: Handhabung des Linearschallkopfes sowie Bildqualität beim unsterilen Prescan, Punktion, Drahtvorschub, Dilatation und Kathetervorschub. Bei der statistischen Analyse wurden T-Tests und Chi²-Tests sowie der Mann-Whitney U-Test mit einem Signifikanzniveau von 0,05 durchgeführt. Ergebnisse: In der MISP-Gruppe war der Risikoscore signifikant niedriger (6,4 vs 11,6 Punkte; T Test: p = 0,004). Die primäre Erfolgsrate war mit der MISP-Technik tendenziell (84 vs 72%, p = 0,134), die Gesamt-Erfolgsrate nach Methoden-Crossover signifikant höher als mit der Landmarken-Technik (86 vs 71%; p = 0,046). In der MISP-Gruppe konnte signifi-kant häufiger unmittelbar erfolgreich mit nur einer Hautpunktion und ohne Richtungswechsel punktiert werden (20/51 vs 4/50; p = 0,001). Arterielle Fehlpunktionen mit Hämatombildung traten in der MISP-Gruppe signifikant seltener auf (2 vs 10; p = 0,013). Die Gesamtzeit der ZVK-Anlage war in der MISP-Gruppe signifikant länger (19:37 vs 14:52; p < 0,001), wobei die Punktionsdauer nicht signifikant unterschiedlich war. In der MISP-Gruppe wurde im Mittel 0,9 cm weiter vom Jugulum entfernt (T-Test: p = 0,015) und 0,5 cm weiter von der Clavicula entfernt punktiert (T-Test: p < 0,001). Bei den restlichen Komplikationen und der Anzahl der Drahtvorschübe gab es in beiden Gruppen keine signifikanten Unterschiede. Beim subjektiven Sicherheitsscore unterschied sich die Punktionssicherheit zwischen der MISP-Gruppe und LUP-Gruppe signifikant (8,0 vs 6,9 Punkte; T-Test: p = 0,027). Schlussfolgerung: In dieser randomisierten Studie wurde erstmals eine Ultraschall-gesteuerte in-plane Punktion der VSC unter Verwendung eines Mikrokonvex-Ultraschallkopfes evaluiert. Wie auch in anderen Studien zur Ultraschall-gesteuerten Punktion der VSC konnten eine höhere Trefferquote und eine geringere Komplikationsrate gegenüber der Landmarken-Technik belegt werden, insbesondere arterielle Fehlpunktionen traten seltener auf. Vor diesem Hintergrund kann auch für die Punktion der VSC eine Empfehlung für Ultraschall-gesteuerte Techniken gegenüber der klassischen Landmarken-Technik ausgesprochen werden.Introduction: The placement of central venous catheters (CVC) is one of the most common invasive procedures in intensive care units. For puncturing the subclavian vein (SCV), there is no clear recommendation for ultrasound-guided CVC placement compared to the internal jugular vein. This may be due to the shape of the linear ultrasound probe typically used for vascular punctures. Our hypothesis is that the effectiveness and safety of CVC placement in the SCV with a microconvex probe using the Microconvex In-Plane Subclavian Puncture (MISP) technique can be improved compared to the standard landmark technique, the Landmark Unsterile Prescan (LUP) technique. Methods: After ethical approval (Ethics Committee of the Saarland Medical Association, HA 08/21), 101 patients undergoing general surgical operations at the Saarland University Medical Center were randomized to the study groups. Primary endpoint was an a priori defined risk score, including eight subpoints: number of puncture attempts, puncture duration (which includes the time from puncture to blood aspiration, wire advancement, and dilation until all CVC limbs are aspiratable), arterial puncture, hematoma formation, posterior venous wall injury, pneumothorax, hemothorax, and catheter misplacement. In case of unsuccessful puncture, the maximum score of the respective group was assigned. Secondary endpoints included success rate (primary as well as total after method crossover), first pass success, individual complications and times, puncture site, number of wire advancements, and a subjective safety score with six subpoints: handling of the linear probe and image quality during the unsterile prescan, puncture, wire advancement, dilation, and catheter insertion. For the statistical analysis, t-tests, chi²-tests, and the Mann-Whitney U-test were performed with a significance level of 0.05. Results: In the MISP group, the risk score was significantly lower (6.4 vs 11.6 points; t test: p = 0.004). The primary success rate tended to be higher with the MISP technique (84 vs 72%, p = 0.134), while the overall success rate including crossover attempts was significantly higher compared to the landmark technique (86 vs 71%; p = 0.046) as was first pass success rate with just one skin puncture and no change in direction (20/51 vs 4/50; p = 0.001). Arterial punctures with hematoma formation occurred significantly less frequently in the MISP group (2 vs 10; p = 0.013). The total time for CVC insertion was significantly longer in the MISP group (19:37 vs 14:52; p < 0.001), although the puncture duration itself was not significantly different. In the MISP group, the puncture was performed on average 0.9 cm further away from the jugulum (t-test: p = 0.015) and 0.5 cm further away from the clavicle (t test: p < 0.001). There were no significant differences between the two groups regarding other complications and the number of wire advancements. In the subjective safety score, puncture safety was scored significantly higher by the performing anesthetists in the MISP group (8.0 vs 6.9 points; t-test: p = 0.027). Conclusion: In this randomized study, an ultrasound-guided in-plane puncture of the SCV was evaluated for the first time using a microconvex ultrasound probe. As in other studies on ultrasound-guided puncture of the SCV, a higher success rate and a lower complication rate were demonstrated compared to the landmark technique, with arterial punctures occurring less frequently. In this context, ultrasound-guided techniques can also be recommended for puncturing the SCV over the traditional landmark technique
Drying of Functional Hydrogels: Development of a Workflow for Bioreactor-Integrated Freeze-Drying of Protein-Coated Alginate Microcarriers for iPS Cell-Based Screenings
Get PDFProtein-coated ultra-high viscosity (UHV)-alginate hydrogels are essential
to mimic the physiological in vivo environment of humans in several in vitro applica tions. This work presents an optimized bioreactor-integrated freeze-drying process for
MatrigelTM-coated UHV-alginate microcarriers in the context of human induced pluripotent
stem cell (hiPSC) expansion. The impact of freeze-drying on the UHV-alginate microcar riers using trehalose 100 mg/mL in 0.9% NaCl as a lyoprotective agent, as well as the
stem cell response using hiPSCs, was analyzed using microscopy-based screenings. First
observations of the process showed that the integrity of the cake was preserved in the
samples with a maximum vapor exchanging rate. Following rehydration, the UHV-alginate
microcarriers retained their original morphology. Upon the addition of Poloxamer 188,
stickiness and bubble formation were reduced. The expansion of hiPSCs in a suspension
bioreactor resulted in a 5–7-fold increase in total cell count, yielding at least 1.3 × 107
cells
with viability exceeding 80% after seven days of cultivation. In flow cytometry analysis, the
pluripotency factors OCT3/4 and SSEA4 resulted in positive signals in over 98% of cells,
while the differentiation factor SSEA1 was positive in fewer than 10% of cells. Supported
by preceding in silico predictions of drying time, this study presents, for the first time, basic
steps toward a “ready-to-use” bioreactor-integrated freeze-drying process for UHV-alginate
microcarriers in the iPSC context
On the Parameterized Complexity of Controlling Amendment and Successive Winners
Get PDFThe amendment procedure and the successive procedure have been widely employed
in parliamentary and legislative decision making and have undergone extensive study
in the literature from various perspectives. However, investigating them through the
lens of computational complexity theory has not been as thoroughly conducted as for
many other prevalent voting procedures heretofore. To the best of our knowledge, there
is only one paper which explores the complexity of several strategic voting problems
under these two procedures, prior to our current work. To provide a better under standing of to what extent the two procedures resist strategic behavior, we study the
parameterized complexity of constructive/destructive control by adding/deleting vot ers/candidates for both procedures. To enhance the generalizability of our results, we
also examine a more generalized form of the amendment procedure. Our exploration
yields a comprehensive (parameterized) complexity landscape of these problems with
respect to numerous parameters
Age-related alterations of angiogenesis, inflammation and bone microarchitecture during fracture healing in mice
Get PDFThe surgical treatment of geriatric patients represents a major challenge in traumatology. It is well known that aging affects fracture healing. However, the exact pathophysiology of age-related changes in angiogenesis, inflammation and bone remodeling remains still elusive. Therefore, we herein studied the differences of femoral fracture healing in young adult (3–4 months) and aged (16–18 months) CD-1 mice by using a stable closed femoral fracture model with intramedullary screw fixation. The callus tissue was analyzed by means of X-ray, micro-computed tomography (µCT), histology and immunohistochemistry. We found a deteriorated trabecular architecture and a reduced bone formation within the callus tissue of aged mice. Moreover, aged animals showed an increased number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts at an early healing time point, whereas the fraction of mature α-smooth muscle actin (SMA)-positive microvessels was significantly reduced. Furthermore, the numbers of macrophages and granulocytes were higher in the callus tissue of aged animals at the end of the healing process. Taken together, these results demonstrate a delayed femoral fracture healing in aged CD-1 mice. This is most likely caused by an early overshooting osteoclast response, a decelerated maturation of the callus microvasculature and a late increased recruitment of pro-inflammatory cells. Targeting these alterations may contribute to the development of novel treatment approaches for the stimulation of bone regeneration in geriatric patients
Einzelzellanalysen von Lungenorganoiden in der translationalen Forschung
Get PDFLung organoids are 3D, self-organizing structures derived from epithelial progenitor cells that replicate key aspects of the human lung. They serve as models for research and drug discovery. Modern methods such as single-cell RNA sequencing elucidate cell differentiation pathways and cellular mechanisms. Comparing results with patient data enhances the relevance of the findings. Organoids provide an ethical alternative to animal experiments and are increasingly replacing animal studies
Post-treatment stability after insertion of CAD/CAM fabricated or Conventional fixed orthodontic retainers: a two-year follow-up
Get PDFObjective
Since relapse after orthodontic treatment and stability and failure of CAD/CAM fabricated and Conventional fixed retainers are widely discussed, this study investigated and compared two-year post-treatment stability after insertion of a CAD/CAM fabricated or Conventional fixed retainer in the lower jaw.
Materials and methods
Digitized dental casts or intraoral scans of n = 60 patients were used for data acquisition. The patients were divided into two groups according to the retention protocol: CAD/CAM fabricated fixed retainer (n = 30, mean age 16.97 ± 5.74 years) and Conventional fixed retainer (n = 30, mean age 15.70 ± 4.19 years). The evaluation included established procedures for dental measurements of the mandible (Intercanine Distance and Little´s Irregularity Index) before orthodontic treatment, at the end of orthodontic treatment, when the fixed retainer was inserted and two years after the insertion of the fixed retainer. All retainers were inserted by the same practitioner. Complications were recorded. Statistics included Shapiro-Wilk-, T- and Friedman-Tests. The level of significance was set at p < 0.05.
Results
In patients with Conventional fixed retainers the change of the Intercanine Distance between insertion of the fixed retainer and two years afterwards was significantly more pronounced than in patients with CAD/CAM fabricated fixed retainers (ICD: Δ CAD/CAMt1−t2: -0.03 ± 0.22 mm; Δ Conventionalt1−t2: 0.12 ± 0.29 mm). Stability of Intercanine Distance was less in patients with Conventional fixed retainers. The change of Little´s Irregularity Index was not significant between the groups. In two patients with a Conventional fixed retainer a bonding surface was renewed within the first three months.
Conclusions
Within two years, CAD/CAM fabricated fixed retainers showed less relapse of Intercanine Distance and fewer complications than Conventional fixed retainers.
Clinical relevance
Considering the amount of relapse and the differences in complications, CAD/CAM fabricated fixed retainers and Conventional fixed retainers are useful appliances for stabilization of treatment results with favorable stability. Fabrication of CAD/CAM based fixed retainers is aside from that timesaving compared to Conventional fixed retainers
Emergency response planning for sudden cardiac arrest in amateur football clubs in Germany (federal state Saarland)
Get PDFObjective While emergency care for sudden cardiac
arrest (SCA) is strictly regulated in professional football,
the situation in amateur football is unclear. This study
investigated the emergency readiness for SCA in German
amateur football clubs.
Methods A cross-sectional survey of 253 German
amateur football clubs (fifth division and lower) was
conducted between January and August 2023. Club
representatives participated in a 30-point questionnaire
on automated external defibrillator (AED) availability,
visibility, purchase, usage, frequency of staff trained in
cardiopulmonary resuscitation (CPR) and AED usage,
regular CPR and AED training, and the existence of an
emergency action plan (EAP).
Results 161 of 253 eligible clubs (64% response rate)
participated. An AED was available in 48/161 (30%)
clubs. 46 of 161 clubs (29%) had no CPR-trained staff.
A high availability of CPR- and AED-trained staff (>75%
likelihood of being present at the pitch) was more likely
during a match (61% and 84%) than training (40% and
51%), respectively. Retrospectively, over 7 years, five clubs
reported that CPR-trained staff used an AED, resulting in
a survival rate of 80%. 16 clubs (10%) had an EAP in the
event of an SCA.
Conclusion German amateur football clubs show low
emergency readiness for SCA despite a promising survival
rate when an AED is used by CPR-trained staff on-site.
Regular CPR and AED training for club members, increased
availability of AEDs, and the development of EAPs might
be beneficial in responding adequately to an SCA during
football training and matche
Effect of isolated keratin 3 knockdown on gene expression of primary limbal epithelial cells without and with inflammatory stimuli
No full textPurpose
Studies have shown that keratin 3 (KRT3) expression is reduced in paired box 6 (PAX6) haploinsufficient primary limbal epithelial cells (LECs). The downregulation of KRT3 expression due to PAX6 haploinsufficiency is likely a critical factor in the development and progression of aniridia associated keratopathy (AAK). In addition, the ocular surface of congenital aniridia patients exhibits an inflammatory environment. The objective of this study was to investigate the isolated effect of KRT3 knockdown, achieved via siRNA silencing in healthy LECs, on PAX6 and other related gene expressions, both under normal and inflammatory conditions.
Methods
To achieve KRT3 knockdown, human primary LECs were transfected with KRT3 siRNA using Lipofectamine 2000. Inflammatory conditions were induced 48 hours after transfection by treating the cells with 2 mg/mL of lipopolysaccharides (LPS) or 1 ng/mL of IL-1β. Subsequently, gene and protein expression levels were analysed using qPCR, Western blotting, and ELISA.
Results
Following KRT3 knockdown at protein level, there was DSG1, ADH7 and PPARγ upregulation and MAPK1 downregulation solely at transcriptional level (p ≤ 0.031). Nevertheless, IL-6 downregulation could be observed both at transcriptional and at protein levels (p ≤ 0.003). Following KRT3 siRNA knockdown, LPS induced inflammation decreased PPARγ mRNA level and IL-1β induced inflammation decreased DSG1 and ADH7 mRNA levels without changes at protein levels (p ≤ 0.014). In contrast, in control knockdown LECs, IL-1β induced inflammation significantly decreased KRT3 mRNA and protein levels and IL-6 protein level (p ≤ 0.02).
Conclusions
In normal LECs, inflammatory stimuli slow differentiation and simultaneously induce IL-6 production. These mechanisms are absent in KRT3 knockdown LECs. As a result, despite the presence of inflammation, KRT3 knockdown LECs continue their differentiation unaltered while maintaining inflammatory IL-6 protein secretion
Borderline personality disorder and antisocial traits in justice-involved males: Associations with aggression, violent crime, and adverse childhood experiences
No full textBorderline personality disorder (BPD) and antisocial traits are common in justice-involved samples, but research on their dynamics, precursors, and aftereffects regarding aggressive and violent behavior is scarce. In order to enlarge the current knowledge needed for effective risk assessment and reduction, the present study examined patterns of BPD and antisocial traits in a sample of 315 justice-involved males who had undergone psychological/psychiatric evaluation, focusing on their relations with adverse childhood experiences (ACEs), self-reported physical aggression, as well as officially registered previous and future violent crime. Based on a comprehensive analysis of psychiatric/psychological evaluation reports and individuals’ self-ratings, latent class analysis identified three distinct classes with (1) high probability of BPD and antisocial traits (n = 63), (2) high probability of antisocial traits only (n = 150), and (3) low probability of either (n = 102). Compared to the latter, both symptomatic classes were characterized by high ACE burden. Whereas the borderline-antisocial class showed associations with increased self-reported physical aggression but not with convictions for violent crimes, the antisocial class was related to both aggression ratings and registered violent offending. Moreover, elevated ACE scores indicated incremental predictability for physical aggression ratings and violent criminality over class membership. The present findings highlight the need to carefully assess personality disturbances and ACEs in justice-involved populations in order to apply the most effective intervention measures to address each individual's criminogenic needs as accurately as possible