Methacrylate-based polymer foams with controllable connectivity, pore shape, pore size and polydispersity.

Polymer foams are becoming increasingly important in industry, especially biodegradable polymer foams are in demand. Depending on the application, polymer foams need to have characteristic properties, which include connectivity and polydispersity. We show how polymer foams with tailor-made structures can be synthesized from water-in-monomer emulsions which were generated via microfluidics. As monomer we used 1,4-butanediol dimethacrylate (1,4-BDDMA). Firstly, we synthesised monodisperse open- and closed-cell poly(1,4-BDDMA) foams with either spherical or hexagonal pore shapes by varying the locus of initiation. Secondly, we were able to control the pore diameters and obtained polymer foams of both connectivities and pore shapes with pore sizes from ∼70 µm up to ∼120 µm by means of one microfluidic chip. Finally, we synthesized poly(1,4-BDDMA) foams with controllable polydispersity. Here, the mean droplet diameter was the same as that of the monodisperse counterparts in order to be able to compare the properties of the resulting polymer foams.

Automated tobacco assessment and cessation support for cancer patients.

BACKGROUND: Tobacco assessment and cessation support are not routinely included in cancer care. An automated tobacco assessment and cessation program was developed to increase the delivery of tobacco cessation support for cancer patients. METHODS: A structured tobacco assessment was incorporated into the electronic health record at Roswell Park Cancer Institute to identify tobacco use in cancer patients at diagnosis and during follow-up. All patients who reported tobacco use within the past 30 days were automatically referred to a dedicated cessation program that provided cessation counseling. Data were analyzed for referral accuracy and interest in cessation support. RESULTS: Between October 2010 and December 2012, 11,868 patients were screened for tobacco use, and 2765 were identified as tobacco users and were referred to the cessation service. In referred patients, 1381 of those patients received only a mailed invitation to contact the cessation service, and 1384 received a mailing as well as telephone contact attempts from the cessation service. In the 1126 (81.4%) patients contacted by telephone, 51 (4.5%) reported no tobacco use within the past 30 days, 35 (3.1%) were medically unable to participate, and 30 (2.7%) declined participation. Of the 1381 patients who received only a mailed invitation, 16 (1.2%) contacted the cessation program for assistance. Three questions at initial consult and follow-up generated over 98% of referrals. Tobacco assessment frequency every 4 weeks delayed referral in < 1% of patients. CONCLUSIONS: An automated electronic health record-based tobacco assessment and cessation referral program can identify substantial numbers of smokers who are receptive to enrollment in a cessation support service.

Hydroxyapatite nanoparticle-modified porous bone grafts with improved cell attachment.

Emulsion-templated foams have displayed promise as injectable bone grafts; however, the use of a surfactant as an emulsifier resulted in relatively small pores and impedes cell attachment. Hydroxyapatite nanoparticles were explored as an alternative stabilizer to address these limitations. To this end, hydroxyapatite nanoparticles were first modified with myristic acid to generate the appropriate balance of hydrophobicity to stabilize a water-in-oil emulsion of neopentyl glycol diacrylate and 1,4-butanedithiol. In situ surface modification of the resulting foam with hydroxyapatite was confirmed with elemental mapping and transmission electron microscopy. Nanoparticle-stabilized foams displayed improved human mesenchymal stem cell viability (91 ± 5%) over surfactant-stabilized foams (23 ± 11%). Although the pore size was appropriate for bone grafting applications (115 ± 71 µm), the foams lacked the interconnected architecture necessary for cell infiltration. We hypothesized that a co-stabilization approach with both surfactant and nanoparticles could be used to achieve interconnected pores while maintaining improved cell attachment and larger pore sizes. A range of hydroxyapatite nanoparticle and surfactant concentrations were investigated to determine the effects on microarchitecture and cell behavior. By balancing these interactions, a co-stabilized foam was identified that possessed large, interconnected pores (108 ± 67 µm) and improved cell viability and attachment. The co-stabilized foam was then evaluated as an injectable bone graft including network formation, microscale integration with bone, push out strength, and compressive properties. Overall, this work demonstrated that in situ surface modification with nHA improved cell attachment while retaining desirable bone grafting features and injectability.

PoreScript: Semi-automated pore size algorithm for scaffold characterization.

The scaffold pore size influences many critical physical aspects of tissue engineering, including tissue infiltration, biodegradation rate, and mechanical properties. Manual measurements of pore sizes from scanning electron micrographs using ImageJ/FIJI are commonly used to characterize scaffolds, but these methods are both time-consuming and subject to user bias. Current semi-automated analysis tools are limited by a lack of accessibility or limited sample size in their verification process. The work here describes the development of a new MATLAB algorithm, PoreScript, to address these limitations. The algorithm was verified using three common scaffold fabrication methods (e.g., salt leaching, gas foaming, emulsion templating) with varying pore sizes and shapes to demonstrate the versatility of this new tool. Our results demonstrate that the pore size characterization using PoreScript is comparable to manual pore size measurements. The PoreScript algorithm was further evaluated to determine the effect of user-input and image parameters (relative image magnification, pixel intensity threshold, and pore structure). Overall, this work validates the accuracy of the PoreScript algorithm across several fabrication methods and provides user-guidance for semi-automated image analysis and increased throughput of scaffold characterization.

Review of Integrin-Targeting Biomaterials in Tissue Engineering.

The ability to direct cell behavior has been central to the success of numerous therapeutics to regenerate tissue or facilitate device integration. Biomaterial scientists are challenged to understand and modulate the interactions of biomaterials with biological systems in order to achieve effective tissue repair. One key area of research investigates the use of extracellular matrix-derived ligands to target specific integrin interactions and induce cellular responses, such as increased cell migration, proliferation, and differentiation of mesenchymal stem cells. These integrin-targeting proteins and peptides have been implemented in a variety of different polymeric scaffolds and devices to enhance tissue regeneration and integration. This review first presents an overview of integrin-mediated cellular processes that have been identified in angiogenesis, wound healing, and bone regeneration. Then, research utilizing biomaterials are highlighted with integrin-targeting motifs as a means to direct these cellular processes to enhance tissue regeneration. In addition to providing improved materials for tissue repair and device integration, these innovative biomaterials provide new tools to probe the complex processes of tissue remodeling in order to enhance the rational design of biomaterial scaffolds and guide tissue regeneration strategies.

The distinct metabolic phenotype of lung squamous cell carcinoma defines selective vulnerability to glycolytic inhibition.

Adenocarcinoma (ADC) and squamous cell carcinoma (SqCC) are the two predominant subtypes of non-small cell lung cancer (NSCLC) and are distinct in their histological, molecular and clinical presentation. However, metabolic signatures specific to individual NSCLC subtypes remain unknown. Here, we perform an integrative analysis of human NSCLC tumour samples, patient-derived xenografts, murine model of NSCLC, NSCLC cell lines and The Cancer Genome Atlas (TCGA) and reveal a markedly elevated expression of the GLUT1 glucose transporter in lung SqCC, which augments glucose uptake and glycolytic flux. We show that a critical reliance on glycolysis renders lung SqCC vulnerable to glycolytic inhibition, while lung ADC exhibits significant glucose independence. Clinically, elevated GLUT1-mediated glycolysis in lung SqCC strongly correlates with high 18F-FDG uptake and poor prognosis. This previously undescribed metabolic heterogeneity of NSCLC subtypes implicates significant potential for the development of diagnostic, prognostic and targeted therapeutic strategies for lung SqCC, a cancer for which existing therapeutic options are clinically insufficient.

HIF-1α-PDK1 axis-induced active glycolysis plays an essential role in macrophage migratory capacity.

In severely hypoxic condition, HIF-1α-mediated induction of Pdk1 was found to regulate glucose oxidation by preventing the entry of pyruvate into the tricarboxylic cycle. Monocyte-derived macrophages, however, encounter a gradual decrease in oxygen availability during its migration process in inflammatory areas. Here we show that HIF-1α-PDK1-mediated metabolic changes occur in mild hypoxia, where mitochondrial cytochrome c oxidase activity is unimpaired, suggesting a mode of glycolytic reprogramming. In primary macrophages, PKM2, a glycolytic enzyme responsible for glycolytic ATP synthesis localizes in filopodia and lammelipodia, where ATP is rapidly consumed during actin remodelling processes. Remarkably, inhibition of glycolytic reprogramming with dichloroacetate significantly impairs macrophage migration in vitro and in vivo. Furthermore, inhibition of the macrophage HIF-1α-PDK1 axis suppresses systemic inflammation, suggesting a potential therapeutic approach for regulating inflammatory processes. Our findings thus demonstrate that adaptive responses in glucose metabolism contribute to macrophage migratory activity.

Thromboembolic complications in burn patients and associated risk factors.

Early mobilization and deep venous thrombosis (DVT) prophylaxis have been shown to reduce the incidence of DVT and pulmonary embolism among hospitalized patients, yet thromboembolic complications remain a great concern, especially to those who remain immobilized for an extended period of time. There are many risk factors associated with the development of thromboembolism, especially DVT. The main objective of this retrospective study is to estimate the occurrence of DVT in burn patients and to investigate some burn-related risk factors. A retrospective examination of DVT cases was conducted among the acute burn patients admitted to our Regional Burn Center during 2008. The analysis included the demographic factors, preexisting medical conditions, ventilator support, number of surgeries and blood transfusions, and use of central line. There was a total of 97 diagnosed patients with DVT and among them 86 were adult acute burn patients. There were 113 diagnosed with DVTs in 86 burn patients, including 22 patients diagnosed with DVT at multiple sites either in one screening or in subsequent screenings. Incidence of DVT at the center was 5.92 per 100 adult acute burn admissions. Men had more DVT than women (6.87 vs. 3.34%, relative risk 2.05, P < .05). The average percentage of %TBSA was smaller in the patients who were more than 50 years of age compared with the patients who were 49 years or younger (21.97 vs. 34.77%, P < .05). Among the patients with DVT, 80 (93%) had a central venous catheter before DVT developed and the other six never had a central venous catheter. The most common site for DVT development was common femoral vein site 89%. The average number of procedures before DVT was 7.84 ± 8.36, and blood transfusions were 39.55 ± 108.37 units. Six patients (7%) died in the hospital within these study cohorts and there was no indication that pulmonary embolism was the cause of the deaths. The study showed that the incidence of DVT in the burn center was comparable with the incidences reported in the literature. Being of male sex, a smoker, an alcoholic, high-age group, high %TBSA, use of central line, increased number of surgeries, and increased number of blood transfusions are identified as possible predisposing factors for DVTs. Further meaningful evaluation to determine the incidence of DVT in burn patients and its associated risk factors will require large multicenter, well-controlled, prospective designed study.