Adaptation to public goods cheats in Pseudomonas aeruginosa

Cooperation in nature is ubiquitous, but is susceptible to social cheats who pay little or no cost of cooperation yet reap the benefits. The effect such cheats have on reducing population productivity suggests that there is selection for cooperators to mitigate the adverse effects of cheats. While mechanisms have been elucidated for scenarios involving a direct association between producer and cooperative product, it is less clear how cooperators may suppress cheating in an anonymous public goods scenario, where cheats cannot be directly identified. Here, we investigate the real-time evolutionary response of cooperators to cheats when cooperation is mediated by a diffusible public good: the production of iron-scavenging siderophores by Pseudomonas aeruginosa. We find that siderophore producers evolved in the presence of a high frequency of non-producing cheats were fitter in the presence of cheats, at no obvious cost to population productivity. A novel morphotype independently evolved and reached higher frequencies in cheat-adapted versus control populations, exhibiting reduced siderophore production but increased production of pyocyanin—an extracellular toxin that can also increase the availability of soluble iron. This suggests that cooperators may have mitigated the negative effects of cheats by downregulating siderophore production and upregulating an alternative iron-acquisition public good. More generally, the study emphasizes that cooperating organisms can rapidly adapt to the presence of anonymous cheats without necessarily incurring fitness costs in the environment they evolve in.

Characteristics, outcomes, prognostic factors and treatment of patients with T-cell prolymphocytic leukemia (T-PLL)

Background

T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive disease. In this study, we report our experience from 119 patients with T-PLL.

Patients and methods

We reviewed the clinico-pathologic records of 119 consecutive patients with T-PLL, who presented to our institution between 1990 and 2016.

Results

One hundred and nineteen patients with T-PLL were analysed. Complex karyotype and aberrations in chromosome 14 were seen in 65% and 52% patients, respectively. Seventy-five patients (63%) were previously untreated and 43 (37%) were initially treated outside our institution. Sixty-three previously untreated patients (84%) received frontline therapies. Overall, 95 patients (80%) have died. Median overall survival (OS) from diagnosis was 19 months [95% confidence interval (CI) 16-26 months]. Using recursive partitioning (RP), we found that patients with hemoglobin < 9.3 g/dl, lactate dehydrogenase (LDH) ≥ 1668 IU/l, white blood cell  ≥ 208 K/l and β2M ≥ 8 mg/l had significantly inferior OS and patients with hemoglobin < 9.3 g/dl had inferior progression-free survival (PFS). In multivariate analysis, we identified that presence of pleural effusion [hazard ratio (HR) 2.08 (95% CI 1.11-3.9); P = 0.02], high LDH (≥ 1668 IU/l) [HR 2.5 (95% CI 1.20-4.24); P < 0.001)], and low hemoglobin (< 9.3 g/dl) [HR 0.33 (95% CI 0.14-0.75); P = 0.008] were associated with shorter OS. Fifty-five previously untreated patients received treatment with an alemtuzumab-based regimen (42 monotherapy and 13 combination with pentostatin). Overall response rate, complete remission rate (CR) for single-agent alemtuzumab and alemtuzumab combined with pentostatin were 83%, 66% and 82%, 73% respectively. In patients who achieved initial CR, stem cell transplantation was not associated with longer PFS and OS.

Conclusion

Outcomes in T-PLL remain poor. Multicenter collaborative effort is required to conduct prospective studies.

Ecological selection of siderophore-producing microbial taxa in response to heavy metal contamination

Some microbial public goods can provide both individual and community-wide benefits, and are open to exploitation by non-producing species. One such example is the production of metal-detoxifying siderophores. Here, we investigate whether conflicting selection pressures on siderophore production by heavy metals - a detoxifying effect of siderophores, and exploitation of this detoxifying effect - result in a net increase or decrease. We show that the proportion of siderophore-producing taxa increases along a natural heavy metal gradient. A causal link between metal contamination and siderophore production was subsequently demonstrated in a microcosm experiment in compost, in which we observed changes in community composition towards taxa that produce relatively more siderophores following copper contamination. We confirmed the selective benefit of siderophores by showing that taxa producing large amounts of siderophore suffered less growth inhibition in toxic copper. Our results suggest that ecological selection will favour siderophore-mediated decontamination, with important consequences for potential remediation strategies.

Rehabilitation and exercise oncology program: translating research into a model of care

INTRODUCTION

The Rehabilitation and Exercise Oncology model of care (ActivOnco) was established to optimize cancer survivorship through exercise prescription and active lifestyle promotion, providing a transition of care from hospital to community. Patients having any cancer diagnosis, stage of disease, and treatment were eligible for evaluation and exercise prescription upon deterioration of performance status. The team of professionals included hospital-based physiotherapists proactively screening for rehabilitation needs, loss of functional independence, and exercise eligibility, plus exercise specialists in a community-based Wellness Centre to provide follow-up or direct access for post-treatment or non-complex patients.

METHODS

From January 2011 to December 2015, the hospital team assessed 1635 patients representing all major cancer sites, and the Wellness Centre team evaluated and prescribed exercise for 1066 participants. Primary interventions provided were education about fatigue management, physical activity promotion, exercise prescription, fracture risk reduction, referral to specialized follow-up services (for example, occupational therapy, lymphedema clinic), and coordination for mobility aids and paratransit services.

RESULTS AND CONCLUSIONS

Implementation of the ActivOnco model of care showed that exercise alone is not a panacea for all functional deterioration associated with the cancer trajectory and its treatment. However, screening to identify rehabilitation needs combined with exercise prescription can effectively improve the quality of survivorship in cancer patients. Program developments are limited by the cost of human resources, lack of hospital-based physical resources, and lack of public funding, all of which significantly limit the scope and development of appropriate services.

Interface structure, precursor rheology and dielectric properties of BaTiO3/PVDF–hfp nanocomposite films prepared from colloidal perovskite nanoparticles

A novel and greatly simplified strategy was developed to fabricate high-permittivity dielectric nanocomposites. Interface structure, precursor rheology and dielectric properties of the 0–3 BaTiO₃/PVDF–hfp nanocomposite film were investigated.

Temporal changes in bile acid levels and 12α-hydroxylation after Roux-en-Y gastric bypass surgery in type 2 diabetes

Since the publication of the above article it has been noted that the author S O'Brien should have been listed as CS O'Brien. The authors should therefore appear as follows: R Dutia, M Embrey, CS O'Brien, RA Haeusler, KK Agénor, P Homel, J McGinty, RP Vincent, J Alaghband-Zadeh, B Staels, CW le Roux, J Yu and B Laferrère The corrected article html and online pdf versions have been amended. The authors wish to apologise for any inconvenience caused.

The Innovative Medicines Initiative's New Drugs for Bad Bugs programme: European public-private partnerships for the development of new strategies to tackle antibiotic resistance

Antibiotic resistance (ABR) is a global public health threat. Despite the emergence of highly resistant organisms and the huge medical need for new drugs, the development of antibacterials has slowed to an unacceptable level worldwide. Numerous government and non-government agencies have called for public-private partnerships and innovative funding mechanisms to address this problem. To respond to this public health crisis, the Innovative Medicines Initiative Joint Undertaking programme has invested more than €660 million, with a goal of matched contributions from the European Commission and the European Federation of Pharmaceutical Industries and Associations, in the development of new antibacterial strategies. The New Drugs for Bad Bugs (ND4BB) programme, an Innovative Medicines Initiative, has the ultimate goal to boost the fight against ABR at every level from basic science and drug discovery, through clinical development to new business models and responsible use of antibiotics. Seven projects have been launched within the ND4BB programme to achieve this goal. Four of them will include clinical trials of new anti-infective compounds, as well as epidemiological studies on an unprecedented scale, which will increase our knowledge of ABR and specific pathogens, and improve the designs of the clinical trials with new investigational drugs. The need for rapid concerted action has driven the funding of seven topics, each of which should add significantly to progress in the fight against ABR. ND4BB unites expertise and provides a platform where the commitment and resources required by all parties are streamlined into a joint public-private partnership initiative of unprecedented scale.

A phase II study of decitabine and gemtuzumab ozogamicin in newly diagnosed and relapsed acute myeloid leukemia and high-risk myelodysplastic syndrome

Decitabine may open the chromatin structure of leukemia cells making them accessible to the calicheamicin epitope of gemtuzumab ozogamicin (GO). A total of 110 patients (median age 70 years; range 27-89 years) were treated with decitabine and GO in a trial designed on model-based futility to accommodate subject heterogeneity: group 1: relapsed/refractory acute myeloid leukemia (AML) with complete remission duration (CRD) <1 year (N=28, 25%); group 2: relapsed/refractory AML with CRD ⩾1 year (N=5, 5%); group 3: untreated AML unfit for intensive chemotherapy or untreated myelodysplastic syndrome (MDS) or untreated myelofibrosis (MF; N=57, 52%); and group 4: AML evolving from MDS or relapsed/refractory MDS or MF (N=20, 18%). Treatment consisted of decitabine 20 mg/m(2) daily for 5 days and GO 3 mg/m(2) on day 5. Post-induction therapy included five cycles of decitabine+GO followed by decitabine alone. Complete remission (CR)/CR with incomplete count recovery was achieved in 39 (35%) patients; group 1= 5/28 (17%), group 2=3/5 (60%), group 3=24/57 (42%) and group 4=7/20 (35%). The 8-week mortality in groups 3 and 4 was 16% and 10%, respectively. Common drug-related adverse events included nausea, mucositis and hemorrhage. Decitabine and GO improved the response rate but not overall survival compared with historical outcomes in untreated AML ⩾60 years.

The phosphoinositide-3-kinase (PI3K)-delta and gamma inhibitor, IPI-145 (Duvelisib), overcomes signals from the PI3K/AKT/S6 pathway and promotes apoptosis in CLL

The functional relevance of the B-cell receptor (BCR) and the evolution of protein kinases as therapeutic targets have recently shifted the paradigm for treatment of B-cell malignancies. Inhibition of p110δ with idelalisib has shown clinical activity in chronic lymphocytic leukemia (CLL). The dynamic interplay of isoforms p110δ and p110γ in leukocytes support the hypothesis that dual blockade may provide a therapeutic benefit. IPI-145, an oral inhibitor of p110δ and p110γ isoforms, sensitizes BCR-stimulated and/or stromal co-cultured primary CLL cells to apoptosis (median 20%, n=57; P<0.0001) including samples with poor prognostic markers, unmutated IgVH (n=28) and prior treatment (n=15; P<0.0001). IPI-145 potently inhibits the CD40L/IL-2/IL-10 induced proliferation of CLL cells with an IC50 in sub-nanomolar range. A corresponding dose-responsive inhibition of pAKT(Ser473) is observed with an IC50 of 0.36 nM. IPI-145 diminishes the BCR-induced chemokines CCL3 and CCL4 secretion to 17% and 37%, respectively. Pre-treatment with 1 μM IPI-145 inhibits the chemotaxis toward CXCL12; reduces pseudoemperipolesis to median 50%, inferring its ability to interfere with homing capabilities of CLL cells. BCR-activated signaling proteins AKT(Ser473), BAD(Ser112), ERK(Thr202/Tyr204) and S6(Ser235/236) are mitigated by IPI-145. Importantly, for clinical development in hematological malignancies, IPI-145 is selective to CLL B cells, sparing normal B- and T-lymphocytes.

Social evolution of toxic metal bioremediation in Pseudomonas aeruginosa

Bacteria are often iron-limited, and hence produce extracellular iron-scavenging siderophores. A crucial feature of siderophore production is that it can be an altruistic behaviour (individually costly but benefitting neighbouring cells), thus siderophore producers can be invaded by non-producing social 'cheats'. Recent studies have shown that siderophores can also bind other heavy metals (such as Cu and Zn), but in this case siderophore chelation actually reduces metal uptake by bacteria. These complexes reduce heavy metal toxicity, hence siderophore production may contribute to toxic metal bioremediation. Here, we show that siderophore production in the context of bioremediation is also an altruistic trait and can be exploited by cheating phenotypes in the opportunistic pathogen Pseudomonas aeruginosa. Specifically, we show that in toxic copper concentrations (i) siderophore non-producers evolve de novo and reach high frequencies, and (ii) producing strains are fitter than isogenic non-producing strains in monoculture, and vice versa in co-culture. Moreover, we show that the evolutionary effect copper has on reducing siderophore production is greater than the reduction observed under iron-limited conditions. We discuss the relevance of these results to the evolution of siderophore production in natural communities and heavy metal bioremediation.

Temporal changes in bile acid levels and 12α-hydroxylation after Roux-en-Y gastric bypass surgery in type 2 diabetes

INTRODUCTION

Gastric bypass surgery (GBP) leads to sustained weight loss and significant improvement in type 2 diabetes (T2DM). Bile acids (BAs), signaling molecules which influence glucose metabolism, are a potential mediator for the improvement in T2DM after GBP. This study sought to investigate the effect of GBP on BA levels and composition in individuals with T2DM.

METHODS

Plasma BA levels and composition and fibroblast growth factor (FGF)-19 levels were measured during fasting and in response to an oral glucose load before and at 1 month and 2 years post GBP in 13 severely obese women with T2DM.

RESULTS

A striking temporal change in BA levels and composition was observed after GBP. During the fasted state, BA concentrations were generally reduced at 1 month, but increased 2 years post GBP. Postprandial BA levels were unchanged 1 month post GBP, but an exaggerated postprandial peak was observed 2 years after the surgery. A significant increase in the 12α-hydroxylated/non12α-hydroxylated BA ratio during fasting and postprandially at 2 years, but not 1 month, post GBP was observed. Significant correlations between BAs vs FGF-19, body weight, the incretin effect and peptide YY (PYY) were also found.

CONCLUSIONS

This study provides evidence that GBP temporally modifies the concentration and composition of circulating BAs in individuals with T2DM, and suggests that BAs may be linked to the improvement in T2DM after GBP.

Metal-carbon fiber composite femoral stems in hip replacements: a randomized controlled parallel-group study with mean ten-year follow-up

BACKGROUND

Attempts to improve proximal load transfer and minimize stress shielding have included reducing the stiffness of femoral stems and using alternative stem materials, including carbon fiber composites. An uncemented implant (SR71) composed of a carbon-fiber-composite distal section and a porous-coated titanium-alloy proximal section, designed to improve proximal load transfer and provide good fixation, was clinically evaluated in a prospective randomized study.

METHODS

Sixty patients were enrolled and randomized to receive either the SR71 stem or an all-metal stem (Stability). All patients received a cemented all-polyethylene acetabular component and a 28-mm metal femoral head. All uncemented stems were implanted by the same surgeon. Patients were followed for up to ten years with repeated assessments of bone mineral density, radiographs, Harris hip scores (HHS), and visual analog scale (VAS) pain scores.

RESULTS

Ten years postoperatively, nineteen patients who had been treated with the SR71 stem and not lost to follow-up showed a significantly greater increase in proximal bone mineral density (Gruen zones 1 [p = 0.003] and 7 [p = 0.0007]) from baseline than did the twenty-two who had been treated with the Stability stem and not lost to follow-up. In contrast, the Stability group showed a significantly greater increase in distal bone mineral density (Gruen zones 2 [p = 0.0004], 3 [p = 0.0001], and 5 [p = 0.0035]) compared with the SR71 group. Radiographs demonstrated one case of progressive migration of an acetabular component used with an SR71 stem and one case of bone resorption in Gruen zones 7 and 14 in a patient treated with a Stability stem. There was no significant difference between the SR71 and Stability stems in terms of changes in the total HHS, HHS for pain, HHS for range of motion, or VAS pain scores ten years postoperatively relative to preoperative levels. There was one reported revision of an SR71 femoral stem at the ten-year review.

CONCLUSIONS

The investigational SR71 implant provided increased proximal bone density and reduced distal bone density. The implant showed promising results at the time of early follow-up, and the clinical outcomes were similar to those of an all-metal stem at the time of a ten-year follow-up.

The influence of immediate knee flexion on blood loss and other parameters following total knee replacement

In an initial randomised controlled trial (RCT) we segregated 180 patients to one of two knee positions following total knee replacement (TKR): six hours of knee flexion using either a jig or knee extension. Outcome measures included post-operative blood loss, fall in haemoglobin, blood transfusion requirements, knee range of movement, limb swelling and functional scores. A second RCT consisted of 420 TKR patients randomised to one of three post-operative knee positions: flexion for three or six hours post-operatively, or knee extension. Positioning of the knee in flexion for six hours immediately after surgery significantly reduced blood loss (p = 0.002). There were no significant differences in post-operative range of movement, swelling, pain or outcome scores between the various knee positions in either study. Post-operative knee flexion may offer a simple and cost-effective way to reduce blood loss and transfusion requirements following TKR. We also report a cautionary note regarding the potential risks of prolonged knee flexion for more than six hours observed during clinical practice in the intervening period between the two trials, with 14 of 289 patients (4.7%) reporting lower limb sensory neuropathy at their three-month review.