Demonstration of In Vitro Host-Guest Complex Formation and Safety of para-Sulfonatocalix[8]arene as a Delivery Vehicle for Two Antibiotic Drugs

The macrocycle para-sulfonatocalix[8]arene, sCX[8], was examined with 2 antibiotic drugs, ciprofloxacin (CIP) and isoniazid. The drugs were shown to form complexes with sCX[8] using proton nuclear magnetic resonance, thermogravimetric analysis, fluorescence spectroscopy, and molecular modeling. Both drugs form 1:1 hydrated (H₂O: 13%-14% w/w) host-guest complexes, with sCX[8] binding around the pyridine ring of isoniazid, and around the piperazine and cyclopropane rings of CIP. From proton nuclear magnetic resonance, the binding constant of isoniazid to sCX[8] was 6.8 (±0.3) × 10³ M^?1. Addition of 2 equivalents of sCX[8] to CIP resulted in a 58% decrease in fluorescence, and time-resolved fluorescence anisotropy of CIP doubles with sCX[8]. Each drug binds into the cavity of the macrocycle, with binding stabilized via combinations of hydrogen bonding, electrostatic interactions, π-π stacking, and hydrophobic effects. The safety of sCX[8] was examined in vitro with human embryonic kidney 293 cells. The IC₅₀ of sCX[8] was 559 μM, which is a minimum of 5-fold higher than the concentration that would be used in the clinic. The in vitro effect of sCX[8] on the action of CIP was examined on a panel of bacterial lines. The results showed that sCX[8] has no inherent antibiotic activity and had no negative effect on the action of CIP.     

Gemcitabine plus vinorelbine in stage IIIB or IV non-small cell lung cancer (NSCLC): a multicentre phase II clinical trial

A phase II study in patients with stage IIIB/IV non-small cell lung cancer (NSCLC) was carried out to evaluate the clinical activity and toxicity of the chemotherapeutic combination of gemcitabine+vinorelbine (GEM/VNR). Forty-five patients (40 male, 5 female) with a median age of 67 years (range 37-73) and a median ECOG performance status of 1 (range 0-2) were enrolled into the trial. Twenty patients had stage IIIB (two positive supraclavicular nodes and 20 cytologically positive pleural effusion), and 25 had stage IV NSCLC. GEM 1000 mg/m(2) diluted in 250 cc(3) of normal saline was administered iv on days 1, 8, and 15, while VNR was given 30 mg/m(2) on days 1 and 8 every 4 weeks. The median number of courses/patient was 4 (range 3-7). According to an intent-to-treat analysis 2 (4%) patients had a complete response and 16 (36%; 95% CL 22-52%) had a partial response for an overall response rate of 40% (95% CL 26-56%). Twelve (27%) patients had stable disease and 15 (33%) were considered as treatment failures. Median overall survival of the whole series was 8+ months with 33% of patients alive at 1 year. Toxicity was generally mild. WHO grade 3-4 neutropenia was recorded in 22% of cases, grade 1-3 liver toxicity in 6% of patients and neutropenia-unrelated fever in 9%. This multicentre phase II study suggests that the GEM/VNR combination regimen is an active and well tolerated regimen in patients with stage IIIB/IV NSCLC. Larger studies comparing cisplatin-based regimens to new schedules without cisplatin are warranted.     

Cardiac Index Declines During Long‐Term Left Ventricular Device Support

To investigate longitudinal trends in valvular and ventricular function with long‐term left ventricular assist device (LVAD) therapy, we analyzed hemodynamic and echocardiographic data of patients with at least 2 years of continuous LVAD support. All 130 patients who underwent HeartMate II implantation at our institution between 2005 and 2012 were reviewed. Twenty patients had hemodynamic and echocardiographic evaluations in both the early (0–6 months) and late (2–3 years) postoperative period. Patients on inotropic therapy or temporary mechanical support were excluded. The average times of early and late hemodynamic evaluations were 59 ± 41 days and 889 ± 160 days, respectively. Cardiac index (CI) declined by an average of 0.4 L/min/m² (P = 0.04) with concomitant increase in pulmonary capillary wedge pressure (PCWP; P = 0.02). The right atrial pressure to PCWP (RAP:PCWP) ratio decreased during LVAD support suggesting improvement in right ventricular function. While there was an increase in degree of aortic insufficiency (AI) at the late follow‐up period (P = 0.008), dichotomization by median decline in CI (?0.4 L/min/m²) indicated no difference in prevalence of AI among the groups. CI declined in patients with HeartMate II after 2 years of continuous support. An increase in preload and afterload was observed in those with the greatest decline in CI.     

Pattern formation and polarity sorting of driven actin filaments on lipid membranes

Collective motion of active matter is ubiquitously observed, ranging from propelled colloids to flocks of bird, and often features the formation of complex structures composed of agents moving coherently. However, it remains extremely challenging to predict emergent patterns from the binary interaction between agents, especially as only a limited number of interaction regimes have been experimentally observed so far. Here, we introduce an actin gliding assay coupled to a supported lipid bilayer, whose fluidity forces the interaction between self-propelled filaments to be dominated by steric repulsion. This results in filaments stopping upon binary collisions and eventually aligning nematically. Such a binary interaction rule results at high densities in the emergence of dynamic collectively moving structures including clusters, vortices, and streams of filaments. Despite the microscopic interaction having a nematic symmetry, the emergent structures are found to be polar, with filaments collectively moving in the same direction. This is due to polar biases introduced by the stopping upon collision, both on the individual filaments scale as well as on the scale of collective structures. In this context, positive half-charged topological defects turn out to be a most efficient trapping and polarity sorting conformation.

Collective motion of active matter is ubiquitous, with observations ranging from flocks of birds (1) and schools of fish (2) to propelled colloids (3). The interactions between agents in such systems lead to the formation of complex structures including clusters, swirls, or lanes of agents moving coherently (4). The structure of the emerging patterns strongly depends on both the agents’ shape and their velocity alignment mechanism. A particular case is that of elongated microscopic particles that translate along their major axis in a quasi-two-dimensional environment and only interact upon collision (5, 6). In the context of cytoskeletal systems, gliding actin filaments or microtubules propelled by molecular motors are found to be able to readily crawl over each other and only retain a weak level of alignment upon binary collisions, which eventually leads at high densities to a diverse set of patterns (7). Such resulting patterns are found to be strongly dependent on this weak microscopic alignment interaction, and therefore, even slightly tuning it causes the system to switch between polar and nematic phases, separated by a coexistence regime (8, 9). Observed structures in cytoskeletal systems with weak to moderate interactions include nematic lanes, polar waves, and vortices (10–12). Conversely, pattern formation in systems of elongated bacteria or granular matter is often based on hard interactions with a strong steric component (13–18). In this repulsion-dominated regime, particles are unable to crawl over each other and must stop upon collision. In the limiting case of spherical self-propelled particles, this kind of steric interaction can lead to a stable phase separation between stuck and moving particles, the so-called motility induced phase separation (MIPS) (19). On the other hand, in the case of elongated particles, steric effects can still act as velocity aligning mechanisms. As orientation mismatches are unstable, particles end up aligning and this leads to flocking behavior rather than to phase separation (5, 20–25). This latter case, in which strong steric constraints dominate binary interactions but alignment is still present, is poorly understood, and how modeling has to be extended to account for the emergent collective behavior of elongated, flexible agents with volume exclusion also remains still under debate (26–30). This is partly due to the lack of microscopic experimental systems allowing to explore this regime. Semiflexible cytoskeletal filaments would be the best candidate, but their volume exclusion is usually too weak. However, having them propelled by motors immobilized on a fluid membrane would be a promising route to bridge this experimental gap (31).Here, we enforce a steric repulsion-dominated interaction, leading to alignment between actin filaments by coupling myosin motors to a fluid-supported lipid bilayer. Because of the slippage of the motors on the membrane, the force propelling the filaments is too weak to enable filaments to crawl over each other and thus effectively implements a repulsion-dominated regime, with filaments stopping upon collisions. Eventually, however, because of the thermal fluctuations of their tips, filaments can align and resume motion. The experimental realization of such a microscopic binary interaction, based on volume exclusion, enables us to observe and quantify the resulting pattern formation process in a system of active semiflexible filaments. We then first characterize the interaction at the single filament scale, showing that it leads to nematic alignment. As the filaments’ density is increased, patterns of collective motion emerge, ranging from clusters to thick streams and vortices. Despite the nematic collision rule, we find the emerging structures to be locally polar. The repulsion-dominated interaction indeed introduces a polar bias not only due to the tendency of active filaments or clusters to keep moving together after a polar collision but also by forcing filaments with similar orientation to stop and accumulate when encountering an obstacle. In particular, at high densities, such an interaction leads to the formation of transient local +1/2 topological defects, which act as wedges and, therefore, effectively trap and polarity-sort motile filaments. We interpret this trapping mechanism as an analog of MIPS for elongated self-propelled particles.