Synergistic effects of proteasome inhibitor carfilzomib in combination with tyrosine kinase inhibitors in imatinib-sensitive and -resistant chronic myeloid leukemia models

The tyrosine kinase inhibitor (TKI) imatinib has transformed the treatment and outlook of chronic myeloid leukemia (CML); however, the development of drug resistance and the persistence of TKI-resistant stem cells remain obstacles to eradicating the disease. Inhibition of proteasome activity with bortezomib has been shown to effectively induce apoptosis in TKI-resistant cells. In this study, we show that exposure to the next generation proteasome inhibitor carfilzomib is associated with a decrease in ERK signaling and increased expression of Abelson interactor proteins 1 and 2 (ABI-1/2). We also investigate the effect of carfilzomib in models of imatinib-sensitive and -resistant CML and demonstrate a potent reduction in proliferation and induction of apoptosis in a variety of models of imatinib-resistant CML, including primitive CML stem cells. Carfilzomib acts synergistically with the TKIs imatinib and nilotinib, even in imatinib-resistant cell lines. In addition, we found that the presence of immunoproteasome subunits is associated with an increased sensitivity to carfilzomib. The present findings provide a rational basis to examine the potential of carfilzomib in combination with TKIs as a potential therapy for CML, particularly in imatinib-resistant disease.

Corrosion resistant fibre reinforced polymer (FRP) reinforcement for bridge deck slabs

This paper discusses the beneficial influence of compressive membrane action in fibre reinforced polymer (FRP)reinforced in-plane restrained slabs in bridge deck slabs and the improved service performance when archingaction occurs. Bridge deck slabs that are exposed to extreme environmental conditions can experience severecorrosion damage. Expansive corrosion in steel reinforcement significantly reduces the design life and durabilityof concrete structures; for example, on one short section of the M1 in Northern Ireland, nearly £1 million was spent last year on the maintenance and repair of bridges due to corrosion. Corrosion-resistant compositereinforcement such as basalt fibre reinforced polymer (BFRP) and glass fibre reinforced polymer (GFRP) provides adurable alternative to reinforcing steel. In this research, two BFRP reinforced slabs and two GFRP reinforced slabswere constructed using high-strength concrete with a target cube compressive strength of 65 N/mm2. The slabsrepresented typical full-scale dimensions of a real bridge deck slab 475 mm wide by 1425 mm long and 150 mmdeep. The service and ultimate behaviour of the slabs are discussed and the results are compared with the relevantdesign guidelines.

Disruption of vitellogenesis and spermatogenesis by triclabendazole (TCBZ) in a TCBZ-resistant isolate of Fasciola hepatica following incubation in vitro with a P-glycoprotein inhibitor

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Sligo TCBZ-resistant fluke isolate was used for these experiments and the Pgp inhibitor selected was R(+)-verapamil [R(+)-VPL]. In the first experiment, flukes were initially incubated for 2 h in R(+)-VPL (100 μ m), then incubated in R(+)-VPL+triclabendazole sulphoxide (TCBZ.SO) (50 μg mL-1, or 133·1 μ m) until flukes ceased movement (at 9 h post-treatment). In a second experiment, flukes were incubated in TCBZ.SO alone and removed from the incubation medium following cessation of motility (after 15 h). In the third experiment, flukes were incubated for 24 h in R(+)-VPL on its own. Changes to the testis tubules and vitelline follicles following drug treatment and following Pgp inhibition were assessed by means of light microscope histology and transmission electron microscopy. Incubation of the Sligo isolate in either R(+)-VPL or TCBZ.SO on their own had a limited impact on the morphology of the two tissues. Greater disruption was observed when the drugs were combined, in terms of the block in development of the spermatogenic and vitelline cells and the apoptotic breakdown of the remaining cells. Sperm formation was severely affected and abnormal. Large spaces appeared in the vitelline follicles and synthesis of shell protein was disrupted. The results of this study support the concept of altered drug efflux in TCBZ-resistant flukes and indicate that drug transporters may play a role in the development of drug resistance.

The difficult-to-treat, therapy-resistant cough: Why are current cough treatments not working and what can we do?

Cough can persist despite exhaustive diagnostic and therapeutic effort and has been termed 'idiopathic' or 'unexplained' but perhaps 'difficult to treat' cough is a more appropriate description. In this article the reasons for poor treatment response are discussed. These include a lack of physician fidelity to management guidelines, patient non-adherence and the lack of effective medicines. A number of randomized controlled trials have been undertaken including low dose opiate therapy, the use of a speech pathology intervention, oral antibiotics and antidepressants. The success or otherwise of such interventions will be discussed. A number of approaches to deal with the problem of 'difficult to treat cough' will be considered.

Synthesis and release kinetics of polymerisable ester drug conjugates towards pH-responsive infection-resistant urinary biomaterials

Herein we report the synthesis, characterisation and hydrolytic release kinetics of a suite of novel, polymerisable ester quinolone conjugates with varying alkenyl chain lengths. Hydrolysis was shown to proceed up to 17-fold faster upon elevation of pH from neutral to pH 9.29, making these conjugates attractive for the development of 'designer' infection-resistant urinary biomaterials exploiting the increase in urine pH reported at the onset of catheter-associated infection to trigger drug release. (C) 2013 Elsevier Ltd. All rights reserved.

A markerless deletion method for genetic manipulation of Burkholderia cenocepacia and other multidrug-resistant gram-negative bacteria

Genetic manipulation of multidrug-resistant bacteria is often difficult and hinders progress in understanding their physiology and pathogenesis. This book chapter highlights advances in genetic manipulation of Burkholderia cenocepacia, which are also applicable to other members of the Burkholderia cepacia complex and multidrug-resistant gram-negative bacteria of other genera. The method detailed here is based on the I-SceI homing endonuclease system, which can be efficiently used for chromosomal integration, deletion, and genetic replacement. This system creates markerless mutations and insertions without leaving a genetic scar and thus can be reused successively to generate multiple modifications in the same strain.

Hot deformation characteristics of a nitride strengthened martensitic heat resistant steel

Constitutive equations including an Arrhenius term have been applied to analyze the hot deformation behavior of a nitride-strengthened (NS) martensitic heat resistant steel in temperature range of 900–1200 °C and strain rate range of 0.001–10 /s. On the basis of analysis of the deformation data, the stress–strain curves up to the peak were divided into four regions, in sequence, representing four processes, namely hardening, dynamic recovery (DRV), dynamic strain induced transformation (DSIT), and dynamic recrystallization (DRX), according to the inflection points in ∂θ/∂σ∂θ/∂σ and ∂(∂θ/∂σ)/∂σ∂(∂θ/∂σ)/∂σ curves. Some of the inflection points have their own meanings. For examples, the minimum of ∂θ/∂σ∂θ/∂σ locates the start of DRV and the maximum of it indicates the start of DRX. The results also showed that the critical strain of DRX was sensitive to ln(Z) below 40, while the critical stress of DRX was sensitive to it above 40. The final microstructures under different deformation conditions were analyzed in terms of softening processes including DRV, DRX, metadynamic crystallization (MDRX) and DSIT.

Analysis of deformation behavior and workability of advanced 9Cr-Nb-V ferritic heat resistant steels

Hot compression tests were carried out on 9Cr–Nb–V heat resistant steels in the temperature range of 600–1200 °C and the strain rate range of 10−2–100 s−1 to study their deformation characteristics. The full recrystallization temperature and the carbon-free bainite phase transformation temperature were determined by the slope-change points in the curve of mean flow stress versus the inverse of temperature. The parameters of the constitutive equation for the experimental steels were calculated, including the stress exponent and the activation energy. The lower carbon content in steel would increase the fraction of precipitates by increasing the volume of dynamic strain-induced (DSIT) ferrite during deformation. The ln(εc) versus ln(Z) and the ln(σc) versus ln(Z) plots for both steels have similar trends. The efficiency of power dissipation maps with instability maps merged together show excellent workability from the strain of 0.05 to 0.6. The microstructure of the experimental steels was fully recrystallized upon deformation at low Z value owing to the dynamic recrystallization (DRX), and exhibited a necklace structure under the condition of 1050 °C/0.1 s−1 due to the suppression of the secondary flow of DRX. However, there were barely any DRX grains but elongated pancake grains under the condition of 1000 °C/1 s−1 because of the suppression of the metadynamic recrystallization (MDRX).

Constitutive modeling, microstructure evolution, and processing map for a nitride-strengthened heat-resistant steel

A constitutive equation was established to describe the deformation behavior of a nitride-strengthened (NS) steel through isothermal compression simulation test. All the parameters in the constitutive equation including the constant and the activation energy were precisely calculated for the NS steel. The result also showed that from the stress-strain curves, there existed two different linear relationships between critical stress and critical strain in the NS steel due to the augmentation of auxiliary softening effect of the dynamic strain-induced transformation. In the calculation of processing maps, with the change of Zener-Hollomon value, three domains of different levels of workability were found, namely excellent workability region with equiaxed-grain microstructure, good workability region with “stripe” microstructure, and the poor workability region with martensitic-ferritic blend microstructure. With the increase of strain, the poor workability region first expanded, then shrank to barely existing, but appeared again at the strain of 0.6.

Efficacy and safety of radium-223 dichloride in patients with castration-resistant prostate cancer and symptomatic bone metastases, with or without previous docetaxel use: A prespecified subgroup analysis from the randomised, double-blind, phase 3 ALSYMPCA trial

Background: Primary results from the phase 3 ALSYMPCA trial showed that radium-223 dichloride (radium-223), a targeted α-emitter, improved overall survival compared with placebo and was well tolerated in patients with castration-resistant prostate cancer and symptomatic bone metastases. We did a prespecified subgroup analysis from ALSYMPCA to assess the effect of previous docetaxel use on the efficacy and safety of radium-223. 

Methods: In the phase 3, randomised, double-blind ALSYMPCA trial, patients with symptomatic castration-resistant prostate cancer, at least two symptomatic bone metastases, no known visceral metastases, and who were receiving best standard of care were randomly assigned (2:1) via an interactive voice response system to receive six injections of radium-223 (50 kBq/kg intravenously) or matching placebo, with one injection given every 4 weeks. Patients had either received previous docetaxel treatment or were unsuitable for or declined docetaxel; previous docetaxel use (yes or no) was a trial stratification factor. We investigated the effect of previous docetaxel use on radium-223 treatment for the primary endpoint of overall survival, the main secondary efficacy endpoints, and safety. Efficacy analyses were done for the intention-to-treat population; safety analyses were done for the safety population. The trial has been completed and is registered with ClinicalTrials.gov, number NCT00699751. 

Findings: Randomisation took place between June 12, 2008, and Feb 1, 2011. 526 (57%) of 921 randomly assigned patients had received previous docetaxel treatment (352 in the radium-223 group and 174 in the placebo group) and 395 (43%) had not (262 in the radium-223 group and 133 in the placebo group). Radium-223 prolonged median overall survival compared with placebo, irrespective of previous docetaxel use (previous docetaxel use, hazard ratio [HR] 0·70, 95% CI 0·56-0·88; p=0·002; no previous docetaxel use, HR 0·69, 0·52-0·92; p=0·01). The benefit of radium-223 compared with placebo was seen in both docetaxel subgroups for most main secondary efficacy endpoints; risk for time to time to first symptomatic skeletal event was reduced with radium-223 versus placebo in patients with previous docetaxel use, but the difference was not significant in those with no previous docetaxel use. 322 (62%) of 518 patients previously treated with docetaxel had grade 3-4 adverse events, compared with 205 (54%) of 383 patients without docetaxel. Patients who had previously been treated with docetaxel had a higher incidence of grade 3-4 thrombocytopenia with radium-223 than with placebo (31 [9%] of 347 patients vs five [3%] of 171 patients), whereas the incidence was similar between treatment groups among patients with no previous docetaxel use (seven [3%] of 253 patients vs one [1%] of 130 patients). The incidences of grade 3-4 anaemia and neutropenia were similar between the radium-223 and placebo groups within both docetaxel subgroups. 

Interpretation: Radium-223 is effective and well tolerated in patients with castration-resistant prostate cancer and symptomatic bone metastases, irrespective of previous docetaxel use. 

Funding: Algeta ASA and Bayer HealthCare Pharmaceuticals.

Molecular surveillance for carbapenemase genes in carbapenem-resistant Pseudomonas aeruginosa in Australian patients with cystic fibrosis.

Summary: The aim of this study was to assess the prevalence of acquired carbapenemase genes amongst carbapenem non-susceptible Pseudomonas aeruginosa isolates in Australian patients with cystic fibrosis (CF). Cross-sectional molecular surveillance for acquired carbapenemase genes was performed on CF P. aeruginosa isolates from two isolate banks comprising: (i) 662 carbapenem resistant P. aeruginosa isolates from 227 patients attending 10 geographically diverse Australian CF centres (2007-2009), and (ii) 519 P. aeruginosa isolates from a cohort of 173 adult patients attending one Queensland CF clinic in 2011. All 1189 P. aeruginosa isolates were tested by polymerase chain reaction (PCR) protocols targeting ten common carbapenemase genes, as well the Class 1 integron intI1 gene and the aadB aminoglycoside resistance gene. No carbapenemase genes were identified among all isolates tested. The intI1 and aadB genes were frequently detected and were significantly associated with the AUST-02 strain (OR 24.6, 95% CI 9.3-65.6; p < 0.0001) predominantly from Queensland patients. Despite the high prevalence of carbapenem resistance in P. aeruginosa in Australian patients with CF, no acquired carbapenemase genes were detected in the study, suggesting chromosomal mutations remain the key resistance mechanism in CF isolates. Systematic surveillance for carbapenemase-producing P. aeruginosa in CF by molecular surveillance is ongoing.

Epidemiological analysis of methicillin-resistant Staphylococcus aureus isolates from adult patients with cystic fibrosis

Using pulsed-field gel electrophoresis, we genotyped 21 methicillin-resistant Staphylococcus aureus isolates from patients attending an adult cystic fibrosis unit. Eleven patients exhibited pulsotypes related to 2 locally endemic strains. Eleven chronically colonized patients were assessed over a period of up to 2 years, and all demonstrated a retention of strain type.

Rifampicin and sodium fusidate reduces the frequency of methicillin-resistant Staphylococcus aureus (MRSA) isolation in adults with cystic fibrosis and chronic MRSA infection

Nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) to patients with cystic fibrosis (CF) frequently results in chronic respiratory tract carriage. This is an increasing problem, adds to the burden of glycopeptide antibiotic use in hospitals, and represents a relative contraindication to lung transplantation. The aim of this study was to determine whether it is possible to eradicate MRSA with prolonged oral combination antibiotics, and whether this treatment is associated with improved clinical status. Adult CF patients (six male, one female) with chronic MRSA infection were treated for six months with rifampicin and sodium fusidate. Outcome data were examined for six months before treatment, on treatment and after treatment. The patients had a mean age of 29.3 (standard deviation=6.3) years and FEV(1) of 36.1% (standard deviation=12.7) predicted. The mean duration of MRSA isolation was 31 months. MRSA isolates identified in these patients was of the same lineage as the known endemic strain at the hospital when assessed by pulsed-field gel electrophoresis. Five of the seven had no evidence of MRSA during and for at least six months after rifampicin and sodium fusidate. The proportion of sputum samples positive for MRSA was lower during the six months of treatment (0.13) and after treatment (0.19) compared with before treatment (0.85) (P<0.0001). There was a reduction in the number of days of intravenous antibiotics per six months with 20.3+/-17.6 on treatment compared with 50.7 before treatment and 33.0 after treatment (P=0.02). There was no change in lung function. Gastrointestinal side effects occurred in three, but led to therapy cessation in only one patient. Despite the use of antibiotics with anti-staphylococcal activity for treatment of respiratory exacerbation, MRSA infection persists. MRSA can be eradicated from the sputum of patients with CF and chronic MRSA carriage by using rifampicin and sodium fusidate for six months. This finding was associated with a significant reduction in the duration of intravenous antibiotic treatment during therapy.