Self-crosslinked fibrous collagen/chitosan blends: Processing, properties evaluation and monitoring of degradation by bi-fluorescence imaging

Porous collagen/chitosan scaffolds with different Collagen:Chitosan (Coll:Ch) ratios were prepared by freeze-drying followed by self-crosslinking via dehydrothermal treatment (DHT) and characterized as biomaterials for tissue engineering. Cy7 and Cy5.5 fluorochromes were covalently grafted to collagen and chitosan, respectively. Thus, it was possible, using optical fluorescence imaging of the two fluorochromes, to simultaneously track their in vivo biodegradation, in a blend scaffold form. The fluorescence signal evolution, due to the bioresorption, corroborated with histological analysis. In vitro cytocompatibility of Coll:Ch blend scaffolds were evaluated with standardized tests. In addition, the scaffolds showed a highly interconnected porous structure. Extent of crosslinking was analyzed by convergent analysis using thermogravimetry, Fourier Transform Infrared Spectroscopy and PBS uptake. The variations observed with these techniques indicate strong interactions between collagen and chitosan (covalent and hydrogen bonds) promoted by the DHT. The mechanical properties were characterized to elucidate the impact of the different processing steps in the sample preparation (DHT, neutralization and sterilization by β-irradiation) and showed a robust processing scheme with low impact of Coll:Ch composition ratio.

Protein synthesis is lowered by 4EBP1 and eIF2-α signaling while protein degradation may be maintained in fasting, hypoxic Amazonian cichlids Astronotus ocellatus

The Amazonian cichlid Astronotus ocellatus is highly tolerant to hypoxia, and is known to reduce its metabolic rate by reducing the activity of energetically expensive metabolic processes when oxygen is lacking in its environment. Our objectives were to determine how protein metabolism is regulated in A. ocellatus during hypoxia. Fish were exposed to a stepwise decrease in air saturation (100%, 20%, 10% and 5%) for 2 h at each level, and sampled throughout the experiment. A flooding dose technique using a stable isotope allowed us to observe an overall decrease in protein synthesis during hypoxia in liver, muscle, gill and heart. We estimate that this decrease in rates of protein synthesis accounts for a 20 to 36% decrease in metabolic rate, which would enable oscars to maintain stable levels of ATP and prolong survival. It was also determined for the first time in fish that a decrease in protein synthesis during hypoxia is likely controlled by signaling molecules (4EBP1 and eIF2-α), and not simply due to a lack of ATP. We could not detect any effects of hypoxia on protein degradation as the levels of NH₄ excretion, indicators of the ubiquitin proteasome pathway, and enzymatic activities of lysosomal and non-lysosomal proteolytic enzymes were maintained throughout the experiment.

EARLY-ESLI study: Long-term experience with eslicarbazepine acetate after first monotherapy failure

PURPOSE

Evaluate real-life experience with eslicarbazepine acetate (ESL) after first monotherapy failure in a large series of patients with focal epilepsy.

METHOD

Multicentre, retrospective, 1-year, observational study in patients older than 18 years, with focal epilepsy, who had failed first antiepileptic drug monotherapy and who received ESL. Data from clinical records were analysed at baseline, 3, 6 and 12 months to assess effectiveness and tolerability.

RESULTS

Eslicarbazepine acetate was initiated in 253 patients. The 1-year retention rate was 92.9%, and the final median dose of ESL was 800 mg. At 12 months, 62.3% of patients had been seizure free for 6 months; 37.3% had been seizure free for 1 year. During follow-up, 31.6% of the patients reported ESL-related adverse events (AEs), most commonly somnolence (8.7%) and dizziness (5.1%), and 3.6% discontinued due to AEs. Hyponatraemia was observed in seven patients (2.8%). After starting ESL, 137 patients (54.2%) withdrew the prior monotherapy and converted to ESL monotherapy; 75.9% were seizure free, 87.6% were responders, 4.4% worsened, and 23.4% reported ESL-related AEs.

CONCLUSION

Use of ESL after first monotherapy failure was associated with an optimal seizure control and tolerability profile. Over half of patients were converted to ESL monotherapy during follow-up.

Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof-of-concept-study

BACKGROUND

Prebiotics have been shown to reduce abdominal symptoms in patients with functional gut disorders, despite that they are fermented by colonic bacteria and may induce gas-related symptoms.

AIM

To investigate changes in the metabolic activity of gut microbiota induced by a recognised prebiotic.

METHODS

Healthy subjects (n = 20) were given a prebiotic (2.8 g/day HOST-G904, HOST Therabiomics, Jersey, Channel Islands) for 3 weeks. During 3-day periods immediately before, at the beginning and at the end of the administration subjects were put on a standard diet (low fibre diet supplemented with one portion of high fibre foods) and the following outcomes were measured: (i) number of daytime gas evacuations for 2 days by means of an event marker; (ii) volume of gas evacuated via a rectal tube during 4 h after a test meal; and (iii) microbiota composition by faecal Illumina MiSeq sequencing.

RESULTS

At the beginning of administration, HOST-G904 significantly increased the number of daily anal gas evacuations (18 ± 2 vs. 12 ± 1 pre-administration; P < 0.001) and the volume of gas evacuated after the test meal (236 ± 23 mL vs. 160 ± 17 mL pre-administration; P = 0.006). However, after 3 weeks of administration, these effects diminished (11 ± 2 daily evacuations, 169 ± 23 mL gas evacuation). At day 21, relative abundance of butyrate producers (Lachnospiraceae) correlated inversely with the volume of gas evacuated (r = -0.52; P = 0.02).

CONCLUSION

The availability of substrates induces an adaptation of the colonic microbiota activity in bacterial metabolism, which produces less gas and associated issues. Clinical trials.gov NCT02618239.

Efficient dehydration and recovery of ionic liquid after lignocellulosic processing using pervaporation

BACKGROUND

Biomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration.

RESULTS

We evaluated a commercially available PV system for IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C₂C₁Im][OAc]) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that >99.9 wt% [C₂C₁Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses.

CONCLUSIONS

These findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.

Optimal search strategies of space-time coupled random walkers with finite lifetimes

We present a simple paradigm for detection of an immobile target by a space-time coupled random walker with a finite lifetime. The motion of the walker is characterized by linear displacements at a fixed speed and exponentially distributed duration, interrupted by random changes in the direction of motion and resumption of motion in the new direction with the same speed. We call these walkers "mortal creepers." A mortal creeper may die at any time during its motion according to an exponential decay law characterized by a finite mean death rate ω(m). While still alive, the creeper has a finite mean frequency ω of change of the direction of motion. In particular, we consider the efficiency of the target search process, characterized by the probability that the creeper will eventually detect the target. Analytic results confirmed by numerical results show that there is an ω(m)-dependent optimal frequency ω=ω(opt) that maximizes the probability of eventual target detection. We work primarily in one-dimensional (d=1) domains and examine the role of initial conditions and of finite domain sizes. Numerical results in d=2 domains confirm the existence of an optimal frequency of change of direction, thereby suggesting that the observed effects are robust to changes in dimensionality. In the d=1 case, explicit expressions for the probability of target detection in the long time limit are given. In the case of an infinite domain, we compute the detection probability for arbitrary times and study its early- and late-time behavior. We further consider the survival probability of the target in the presence of many independent creepers beginning their motion at the same location and at the same time. We also consider a version of the standard "target problem" in which many creepers start at random locations at the same time.

Abstract P4-16-09: Phase 1b/2 trial of the HER3 inhibitor patritumab (U3-1287) in combination with trastuzumab plus paclitaxel in newly-diagnosed patients with HER2+ metastatic breast cancer (MBC)

Background: Patritumab is a fully human anti-HER3 monoclonal antibody that has shown potent antitumor activity in vivo. HER3 is a key dimerization partner for other HER family members, and studies suggest that the HER3:HER2 heterodimer is the most potent signaling pair. Therefore, combined inhibition of HER3 and HER2 may synergistically inhibit breast cancer tumor growth. In the CLEOPATRA trial, pertuzumab combined with trastuzumab and docetaxel prolonged progression-free survival compared to trastuzumab and docetaxel alone, demonstrating the benefit of comprehensive blockade of HER2 dimer signaling. Trastuzumab is approved in combination with paclitaxel for first-line treatment of HER2+ MBC. This phase 1b/2 study is investigating patritumab in combination with trastuzumab and paclitaxel in patients (pts) with newly-diagnosed MBC. Results of the phase 1b portion are reported here.

Methods: Eligible pts had HER2+ newly-diagnosed MBC. In the open-label, phase 1b portion of this trial, pts received intravenous (IV) patritumab 18 mg/kg in combination with trastuzumab (8 mg/kg IV loading dose; 6 mg/kg IV maintenance dose) and paclitaxel (175 mg/m2 IV) every 3 weeks (Q3W). In the event that 18 mg/kg was not tolerated based on dose-limiting toxicity (DLT) assessment, sequential cohorts were to receive de-escalating doses of patritumab. Phase 1b study end points included adverse event (AE) incidence, human antihuman antibody (HAHA) formation, pharmacokinetics (PK), and tumor response.

Results: Six pts were enrolled in the phase 1b portion of the trial, with a median age of 61 years (range, 51-78). There were no reported DLTs. Grade ≥3 treatment-related AEs occurred in 3 pts: 1 pt had a serious AE of grade 3 pneumonia; 1 pt had grade 3 worsening of arm pain; 1 pt had grade 3 oral mucositis, prolonged QTc, flu-like syndrome, and increased transaminases. In this limited pt population, most ECG changes were within or slightly above normal limits of the QTc interval. Only 2 pts had increased values close to 50 msec compared with baseline. It should be noted that baseline QTc values for 3 pts (including the pt that experienced grade 3 prolonged QTc) were close to the upper limit of normal. There were no grade 4 AEs, and no other serious AEs. All other treatment-related AEs were grades 1 or 2. All 6 pts tested negative for HAHA formation after drug administration. PK data are consistent with previous studies with patritumab. Two pts had complete response (CR) as their best overall response, 2 pts had partial response (PR), 1 pt had stable disease, and 1 pt was not evaluated for tumor response. All 6 pts have discontinued treatment; 2 due to progressive disease, 3 due to pt decision (2 with CR and 1 with PR), and 1 at the investigator's discretion.

Conclusions: Results to date indicate that the combination of patritumab with trastuzumab and paclitaxel is generally well tolerated, with a promising response rate. As no DLTs were reported, the recommended phase 2 dose is patritumab 18 mg/kg with trastuzumab (8 mg/kg loading; 6 mg/kg maintenance) and paclitaxel 175 mg/m2 Q3W.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-09.