Borderline Personality Pathology in an At Risk Mental State Sample.

Introduction: Transient psychotic symptoms in patients with borderline personality disorder seem to be similar to those in patients with psychotic disorders. Especially in the field of early detection of psychosis, this might lead to individuals with borderline personality disorder being wrongly classified as subjects at risk for developing a manifest psychosis. The aim of the present study was to investigate the occurrence of borderline symptoms in a sample of subjects at risk for psychosis as well as possible effects on the transition rate. Methods: Seventy help-seeking individuals of an early psychosis recognition center were additionally examined for borderline symptoms by the borderline symptom checklist. Results: We found a significant correlation between borderline symptomatology and positive symptoms assessed by the structured interview for prodromal symptoms. There were no associations between basic symptoms for psychosis and borderline symptoms. In addition, there was no influence of borderline symptomatology on the rate of transition into a manifest schizophrenic disease. Summary: In conclusion, borderline personality disorder should not be an exclusion criterion for the screening for psychosis or for an early intervention treatment. On the other hand, not every patient with borderline personality disorder, (especially those not suffering from hallucinations, unusual thought content, or persecutory ideas) should automatically be screened for the risk of developing a psychotic disorder.

Active multi-point microrheology of cytoskeletal networks.

Active microrheology is a valuable tool to determine viscoelastic properties of polymer networks. Observing the response of the beads to the excitation of a reference leads to dynamic and morphological information of the material. In this work we present an expansion of the well-known active two-point microrheology. By measuring the response of multiple particles in a viscoelastic medium in response to the excitation of a reference particle, we are able to determine the force propagation in the polymer network. For this purpose a lock-in technique is established that allows for extraction of the periodical motion of embedded beads. To exert a sinusoidal motion onto the reference bead an optical tweezers setup in combination with a microscope is used to investigate the motion of the response beads. From the lock-in data the so called transfer tensor can be calculated, which is a direct measure for the ability of the network to transmit mechanical forces. We also take a closer look at the influence of noise on lock-in measurements and state some simple rules for improving the signal-to-noise ratio.

Selective adsorption of functionalized nanoparticles to patterned polymer brush surfaces and its probing with an optical trap.

The site-specific attachment of nanoparticles is of interest for biomaterials or biosensor applications. Polymer brushes can be used to regulate this adsorption, so the conditions for selective adsorption of phosphonate-functionalized nanoparticles onto micropatterned polymer brushes with different functional groups are optimized. By choosing the strong polyelectrolytes poly(3-sulfopropyl methacrylate), poly(sulfobetaine methacrylate), and poly[2-(methacryloyloxy)ethyl trimethylammonium chloride], it is possible to direct the adsorption of nanoparticles to specific regions of the patterned substrates. A pH-dependent adsorption can be achieved by using the polycarboxylate brush poly(methacrylic acid) (PMAA) as substrate coating. On PMAA brushes, the nanoparticles switch from attachment to the brush regions to attachment to the grooves of a patterned substrate on changing the pH from 3 to 7. In this manner, patterned substrates are realized that assemble nanoparticles in pattern grooves, in polymer brush areas, or substrates that resist the deposition of the nanoparticles. The nanoparticle deposition can be directed in a pH-dependent manner on a weak polyelectrolyte, or is solely charge-dependent on strong polyelectrolytes. These results are correlated with surface potential measurements and show that an optical trap is a versatile method to directly probe interactions between nanoparticles and polymer brushes. A model for these interactions is proposed based on the optical trap measurements.

Attitudes towards help-seeking and stigma among young people at risk for psychosis.

The role of self-labeling as 'mentally ill' and of stigma-related stress for help-seeking among young people at risk for psychosis is unknown. Stronger self-labeling and less stigma stress predicted better attitudes towards psychiatric medication and psychotherapy, controlling for clinical and sociodemographic variables. Interventions could target stigma-related stress to increase help-seeking.

Technical advance: Inhibition of neutrophil chemotaxis by colchicine is modulated through viscoelastic properties of subcellular compartments.

Colchicine is an efficient drug for the management of inflammatory diseases, such as gouty arthritis and familial Mediterranean fever. It affects neutrophil activity by interfering with the formation of microtubules. To test the hypothesis that therapeutic concentrations of colchicine modulate the mechanical properties of these cells, we applied a combination of biophysical techniques (optical stretching and microrheology) to analyze cellular deformability. The contribution of the subcellular compartments to the regulation of cell mechanics was determined by fitting a multicomponent model of cellular viscoelasticity to time-dependent deformation curves. Neutrophils were found to be less deformable in response to 10 ng/ml colchicine. The model-based analysis of cellular deformation revealed a decrease in cytoplasmatic elasticity and a substantial increase in both elasticity and viscosity of the cell membrane compartment in response to colchicine. These results correlate with a reduced number of cytoplasmatic microtubules and an increase in subcortical actin filaments. The latter finding was confirmed by microrheology and fluorescence microscopy. Neutrophil migration through small pores requiring substantial cellular deformations, but not through large pores, was significantly impaired by colchicine. These data demonstrate that colchicine determines mechanics of neutrophils and, thereby, motility in confined spaces, which is crucial during extravasation of neutrophils in response to inflammatory stimuli.

Properties of intermediate filament networks assembled from keratin 8 and 18 in the presence of Mg²+.

The mechanical properties of epithelial cells are modulated by structural changes in keratin intermediate filament networks. To investigate the relationship between network architecture and viscoelasticity, we assembled keratin filaments from recombinant keratin proteins 8 (K8) and 18 (K18) in the presence of divalent ions (Mg(2+)). We probed the viscoelastic modulus of the network by tracking the movement of microspheres embedded in the network during assembly, and studied the network architecture using scanning electron microscopy. Addition of Mg(2+) at physiological concentrations (<1 mM) resulted in networks whose structure was similar to that of keratin networks in epithelial cells. Moreover, the elastic moduli of networks assembled in vitro were found to be within the same magnitude as those measured in keratin networks of detergent-extracted epithelial cells. These findings suggest that Mg(2+)-induced filament cross-linking represents a valid model for studying the cytoskeletal mechanics of keratin networks.