The influence of pH and salt concentration on the microstructure and mechanical properties of meniscus extracellular matrix-derived implants

Meniscus-related injuries are a common orthopedic challenge with an increasing incidence in the population. While the preservation of viable meniscal tissue is the preferred approach in repair strategies, complex or total traumatic lesions may require alternative therapeutic approaches such as meniscal reconstruction using allografts or engineered equivalents. Although clinical studies suggest promising outcomes with the use of acellular implants, further development is needed to improve their biological and mechanical requirements. Decellularized extracellular matrix (dECM) derived from menisci is a promising biomaterial for meniscus tissue engineering due to its recapitulation of the native tissue environment and the maintenance of tissue-specific cues. However, the associated mechanical limitations of dECM-derived scaffolds frequently impedes their adoption, requiring additional reinforcement or combining with stiffer biomaterials to increase their load-bearing properties. In this study, decellularized extracellular matrix was extracted and its fibrillation was controlled by adjusting both pH and salt concentrations to fabricate mechanically functional meniscal tissue equivalents. The effect of collagen fibrillation on the mechanical properties of the dECM constructs was assessed, and porcine-derived fibrochondrocytes were used to evaluate in vitro biocompatibility. It was also possible to fabricate meniscus-shaped implants by casting of the dECM and to render the implants suitable for off-the-shelf use by adopting a freeze-drying preservation method. Suture pull-out tests were also performed to assess the feasibility of using existing surgical methods to fix such implants within a damaged meniscus. This study highlights the potential of utilizing ECM-derived materials for meniscal tissue substitutes that closely mimic the mechanical and biological properties of native tissue.

Melt electrowritten scaffold architectures to mimic tissue mechanics and guide neo-tissue orientation

All human tissues present with unique mechanical properties critical to their function. This is achieved in part through the specific architecture of the extracellular matrix (ECM) fibres within each tissue. An example of this is seen in the walls of the vasculature where each layer presents with a unique ECM orientation critical to its functions. Current adopted vascular grafts to bypass a stenosed/damaged vessel fail to recapitulate this unique mechanical behaviour, particularly in the case of small diameter vessels (<6 mm), leading to failure. Therefore, in this study, melt-electrowriting (MEW) was adopted to produce a range of fibrous scaffolds to mimic the extracellular matrix (ECM) architecture of the tunica media of the vasculature, in an attempt to match the mechanical and biological behaviour of the native porcine tissue. Initially, the range of collagen architectures within the native vessel was determined, and subsequently replicated using MEW (winding angles (WA) 45°, 26.5°, 18.4°, 11.3°). These scaffolds recapitulated the anisotropic, non-linear mechanical behaviour of native carotid blood vessels. Moreover, these grafts facilitated human mesenchymal stem cell (hMSC) infiltration, differentiation, and ECM deposition that was independent of WA. The bioinspired MEW fibre architecture promoted cell alignment and preferential neo-tissue orientation in a manner similar to that seen in native tissue, particularly for WA 18.4° and 11.3°, which is a mandatory requirement for long-term survival of the regenerated tissue post-scaffold degradation. Lastly, the WA 18.4° was translated to a tubular graft and was shown to mirror the mechanical behaviour of small diameter vessels within physiological strain. Taken together, this study demonstrates the capacity to use MEW to fabricate bioinspired scaffolds to mimic the tunica media of vessels and recapitulate vascular mechanics which could act as a framework for small diameter graft development to guide tissue regeneration and orientation.

Integrating Melt Electrowriting and Fused Deposition Modeling to Fabricate Hybrid Scaffolds Supportive of Accelerated Bone Regeneration

Emerging additive manufacturing (AM) strategies can enable the engineering of hierarchal scaffold structures for guiding tissue regeneration. Here, the advantages of two AM approaches, melt electrowriting (MEW) and fused deposition modelling (FDM), are leveraged and integrated to fabricate hybrid scaffolds for large bone defect healing. MEW is used to fabricate a microfibrous core to guide bone healing, while FDM is used to fabricate a stiff outer shell for mechanical support, with constructs being coated with pro-osteogenic calcium phosphate (CaP) nano-needles. Compared to MEW scaffolds alone, hybrid scaffolds prevent soft tissue collapse into the defect region and support increased vascularization and higher levels of new bone formation 12 weeks post-implantation. In an additional group, hybrid scaffolds are also functionalized with BMP2 via binding to the CaP coating, which further accelerates healing and facilitates the complete bridging of defects after 12 weeks. Histological analyses demonstrate that such scaffolds support the formation of well-defined annular bone, with an open medullary cavity, smooth periosteal surface, and no evidence of abnormal ectopic bone formation. These results demonstrate the potential of integrating different AM approaches for the development of regenerative biomaterials, and in particular, demonstrate the enhanced bone healing outcomes possible with hybrid MEW-FDM constructs.

Bioprinting of scaled-up meniscal grafts by spatially patterning phenotypically distinct meniscus progenitor cells within melt electrowritten scaffolds

Meniscus injuries are a common problem in orthopedic medicine and are associated with a significantly increased risk of developing osteoarthritis. While developments have been made in the field of meniscus regeneration, the engineering of cell-laden constructs that mimic the complex structure, composition and biomechanics of the native tissue remains a significant challenge. This can be linked to the use of cells that are not phenotypically representative of the different zones of the meniscus, and an inability to direct the spatial organization of engineered meniscal tissues. In this study we investigated the potential of zone-specific meniscus progenitor cells (MPCs) to generate functional meniscal tissue following their deposition into melt electrowritten (MEW) scaffolds. We first confirmed that fibronectin selected MPCs from the inner and outer regions of the meniscus maintain their differentiation capacity with prolonged monolayer expansion, opening their use within advanced biofabrication strategies. By depositing MPCs within MEW scaffolds with elongated pore shapes, which functioned as physical boundaries to direct cell growth and extracellular matrix production, we were able to bioprint anisotropic fibrocartilaginous tissues with preferentially aligned collagen networks. Furthermore, by using MPCs isolated from the inner (iMPCs) and outer (oMPCs) zone of the meniscus, we were able to bioprint phenotypically distinct constructs mimicking aspects of the native tissue. An iterative MEW process was then implemented to print scaffolds with a similar wedged-shaped profile to that of the native meniscus, into which we deposited iMPCs and oMPCs in a spatially controlled manner. This process allowed us to engineer sulfated glycosaminoglycan and collagen rich constructs mimicking the geometry of the meniscus, with MPCs generating a more fibrocartilage-like tissue compared to the mesenchymal stromal/stem cells. Taken together, these results demonstrate how the convergence of emerging biofabrication platforms with tissue-specific progenitor cells can enable the engineering of complex tissues such as the meniscus.

Chondroitinase ABC Treatment Improves the Organization and Mechanics of 3D Bioprinted Meniscal Tissue

The meniscus is a fibrocartilage tissue that is integral to the correct functioning of the knee joint. The tissue possesses a unique collagen fiber architecture that is integral to its biomechanical functionality. In particular, a network of circumferentially aligned collagen fibers function to bear the high tensile forces generated in the tissue during normal daily activities. The limited regenerative capacity of the meniscus has motivated increased interest in meniscus tissue engineering; however, the in vitro generation of structurally organized meniscal grafts with a collagen architecture mimetic of the native meniscus remains a significant challenge. Here we used melt electrowriting (MEW) to produce scaffolds with defined pore architectures to impose physical boundaries upon cell growth and extracellular matrix production. This enabled the bioprinting of anisotropic tissues with collagen fibers preferentially oriented parallel to the long axis of the scaffold pores. Furthermore, temporally removing glycosaminoglycans (sGAGs) during the early stages of in vitro tissue development using chondroitinase ABC (cABC) was found to positively impact collagen network maturation. Specially we found that temporal depletion of sGAGs is associated with an increase in collagen fiber diameter without any detrimental effect on the development of a meniscal tissue phenotype or subsequent extracellular matrix production. Moreover, temporal cABC treatment supported the development of engineered tissues with superior tensile mechanical properties compared to empty MEW scaffolds. These findings demonstrate the benefit of temporal enzymatic treatments when engineering structurally anisotropic tissues using emerging biofabrication technologies such as MEW and inkjet bioprinting.

Bioprinting of structurally organized meniscal tissue within anisotropic melt electrowritten scaffolds

The meniscus is characterised by an anisotropic collagen fibre network which is integral to its biomechanical functionality. The engineering of structurally organized meniscal grafts that mimic the anisotropy of the native tissue remains a significant challenge. In this study, inkjet bioprinting was used to deposit a cell-laden bioink into additively manufactured scaffolds of differing architectures to engineer fibrocartilage grafts with user defined collagen architectures. Polymeric scaffolds consisting of guiding fibre networks with varying aspect ratios (1:1; 1:4; 1:16) were produced using either fused deposition modelling (FDM) or melt electrowriting (MEW), resulting in scaffolds with different internal architectures and fibre diameters. Scaffold architecture was found to influence the spatial organization of the collagen network laid down by the jetted cells, with higher aspect ratios (1:4 and 1:16) supporting the formation of structurally anisotropic tissues. The MEW scaffolds supported the development of a fibrocartilaginous tissue with compressive mechanical properties similar to that of native meniscus, while the anisotropic tensile properties of these constructs could be tuned by altering the fibre network aspect ratio. This MEW framework was then used to generate scaffolds with spatially distinct fibre patterns, which in turn supported the development of heterogenous tissues consisting of isotropic and anisotropic collagen networks. Such bioprinted tissues could potentially form the basis of new treatment options for damaged and diseased meniscal tissue. STATEMENT OF SIGNIFICANCE: This study describes a multiple tool biofabrication strategy which enables the engineering of spatially organized fibrocartilage tissues. The architecture of MEW scaffolds can be tailored to not only modulate the directionality of the collagen fibres laid down by cells, but also to tune the anisotropic tensile mechanical properties of the resulting constructs, thereby enabling the engineering of biomimetic meniscal-like tissues. Furthermore, the inherent flexibility of MEW enables the development of zonally defined and potentially patient-specific implants.

Scaffold microarchitecture regulates angiogenesis and the regeneration of large bone defects

Emerging 3D printing technologies can provide exquisite control over the external shape and internal architecture of scaffolds and tissue engineered constructs, enabling systematic studies to explore how geometric design features influence the regenerative process. Here we used fused deposition modelling (FDM) and melt electrowriting (MEW) to investigate how scaffold microarchitecture influences the healing of large bone defects. FDM was used to fabricate scaffolds with relatively large fibre diameters and low porosities, while MEW was used to fabricate scaffolds with smaller fibre diameters and higher porosities, with both scaffolds being designed to have comparable surface areas. Scaffold microarchitecture significantly influenced the healing response following implantation into critically sized femoral defects in rats, with the FDM scaffolds supporting the formation of larger bone spicules through its pores, while the MEW scaffolds supported the formation of a more round bone front during healing. After 12 weeks in vivo, both MEW and FDM scaffolds supported significantly higher levels of defect vascularisation compared to empty controls, while the MEW scaffolds supported higher levels of new bone formation. Somewhat surprisingly, this superior healing in the MEW group did not correlate with higher levels of angiogenesis, with the FDM scaffold supporting greater total vessel formation and the formation of larger vessels, while the MEW scaffold promoted the formation of a dense microvasculature with minimal evidence of larger vessels infiltrating the defect region. To conclude, the small fibre diameter, high porosity and high specific surface area of the MEW scaffold proved beneficial for osteogenesis and bone regeneration, demonstrating that changes in scaffold architecture enabled by this additive manufacturing technique can dramatically modulate angiogenesis and tissue regeneration without the need for complex exogenous growth factors. These results provide a valuable insight into the importance of 3D printed scaffold architecture when developing new bone tissue engineering strategies.

Methacrylated Cartilage ECM-Based Hydrogels as Injectables and Bioinks for Cartilage Tissue Engineering

Articular cartilage (AC) possesses a limited healing potential, meaning that untreated focal joint defects typically progress, leading to the development of degenerative diseases such as osteoarthritis. Several clinical strategies exist that aim to regenerate AC; however, recapitulation of a fully functional, load-bearing tissue remains a significant challenge. This can be attributed, at least in part, to a paucity of biomaterials that truly mimic the native tissue and provide appropriate cues to direct its regeneration. The main structural component of articular cartilage, type II collagen, does not readily gelate at body temperature, challenging the development of cartilage extracellular matrix (cECM)-derived injectable hydrogels and bioinks for AC tissue engineering and bioprinting applications. Here, we describe the development and rheological characterisation of a methacrylated cartilage ECM-based hydrogel/bioink (cECM-MA), which could be photocrosslinked when exposed to ultraviolet (UV) light. Functionalisation of the collagen backbone with methacryloyl groups had a negligible effect on triple helix stability, as demonstrated by circular dichroism spectroscopy. These cECM-MA bioinks demonstrated shear-thinning properties and could be loaded with bone marrow mesenchymal stem cells (BM-MSCs), micro-extruded to generate self-supporting 3D constructs of predefined size and shape, and then photocrosslinked using UV light. Analysis of the cell-laden constructs showed that the BM-MSCs were viable post-printing and underwent chondrogenesis in vitro, generating a tissue rich in sulphated glycosaminoglycans and collagens. These results support the use of methacrylated, tissue-specific ECM-derived hydrogels as bioinks for 3D bioprinting and/or as injectables for cartilage tissue engineering applications.

Biomanufacturing in low Earth orbit for regenerative medicine

Research in low Earth orbit (LEO) has become more accessible. The 2020 Biomanufacturing in Space Symposium reviewed space-based regenerative medicine research and discussed leveraging LEO to advance biomanufacturing for regenerative medicine applications. The symposium identified areas where financial investments could stimulate advancements overcoming technical barriers. Opportunities in disease modeling, stem-cell-derived products, and biofabrication were highlighted. The symposium will initiate a roadmap to a sustainable market for regenerative medicine biomanufacturing in space. This perspective summarizes the 2020 Biomanufacturing in Space Symposium, highlights key biomanufacturing opportunities in LEO, and lays the framework for a roadmap to regenerative medicine biomanufacturing in space.

Targeted Type 2 Alveolar Cell Depletion. A Dynamic Functional Model for Lung Injury Repair

Type 2 alveolar epithelial cells (AEC2) are regarded as the progenitor population of the alveolus responsible for injury repair and homeostatic maintenance. Depletion of this population is hypothesized to underlie various lung pathologies. Current models of lung injury rely on either uncontrolled, nonspecific destruction of alveolar epithelia or on targeted, nontitratable levels of fixed AEC2 ablation. We hypothesized that discrete levels of AEC2 ablation would trigger stereotypical and informative patterns of repair. To this end, we created a transgenic mouse model in which the surfactant protein-C promoter drives expression of a mutant SR39TK herpes simplex virus-1 thymidine kinase specifically in AEC2. Because of the sensitivity of SR39TK, low doses of ganciclovir can be administered to these animals to induce dose-dependent AEC2 depletion ranging from mild (50%) to lethal (82%) levels. We demonstrate that specific levels of AEC2 depletion cause altered expression patterns of apoptosis and repair proteins in surviving AEC2 as well as distinct changes in distal lung morphology, pulmonary function, collagen deposition, and expression of remodeling proteins in whole lung that persist for up to 60 days. We believe SPCTK mice demonstrate the utility of cell-specific expression of the SR39TK transgene for exerting fine control of target cell depletion. Our data demonstrate, for the first time, that specific levels of type 2 alveolar epithelial cell depletion produce characteristic injury repair outcomes. Most importantly, use of these mice will contribute to a better understanding of the role of AEC2 in the initiation of, and response to, lung injury.

Abstract P1-08-09: Increased prevalence of luminal B subtype in Colombian women with breast cancer

Background: Breast cancer is the most frequent malignancy in women worldwide. Distinct intrinsic subtypes of breast cancer have different prognoses, and their relative prevalence varies significantly among ethnic groups. Hispanic/Latino (H/L) populations are a genetically admixed and heterogeneous group, with variable levels of European, Native American and African ancestries. Breast cancer in H/L patients is understudied from a molecular standpoint, and most studies reported so far include limited numbers of H/L patients and assign ethnicity based on self-reported data rather than ancestry. This is the first study to explore the prevalence of breast cancer intrinsic subtypes in Colombia and their association with clinicopathological data and genetic ancestry.

Methods: Immunohistochemistry surrogates from the 2013 St. Gallen International Expert Consensus were applied to classify breast cancer into intrinsic subtypes in 301 patients diagnosed between 2008 and 2012 at the Colombian National Cancer Institute. We analyzed the distribution of subtypes by age, histologic type, node status, margins at surgery, AJCC stage, tumor size, Bloom-Richardson grade, histologic features, administration and response to neoadjuvant therapy, adjuvant therapy and recurrence. Genetic ancestry was estimated from a panel of 80 ancestry-informative markers (AIM).

Results: Luminal B breast cancer subtype was the most prevalent in our population (47.5%), followed by luminal A (23.9%), non-basal triple negative (9.3%), basal-like (8.6%), HER2-enriched (8%), and unknown (2.6%). The average of age at diagnosis was 55 and the average tumor size was 4.08 cm. We found statistical significant differences in age at diagnosis, Bloom-Richardson grade, histologic features, adjuvant chemotherapy and recurrence according to intrinsic subtype. Consistent with North American and European observations, basal-like and non-basal triple negative were poorly differentiated tumors and more likely to be diagnosed at younger ages compared to luminal tumors. Patients diagnosed with HER2-enriched, basal and non-basal triple negative breast cancer had the highest African ancestry.

Conclusions: Luminal B tumors, a high risk subset of ER-positive breast cancer, occur with remarkably higher prevalence in Colombian women with breast cancer compared to North American and European populations. Triple-negative subtypes and HER2-enriched tumors appeared to be more frequent among patients with African ancestry, as observed in North American cohorts. Future studies analyzing the molecular profiles of breast cancer in Colombian women will help us understand the molecular basis of this subtype distribution and compare the molecular characteristics of the different intrinsic subtypes in Colombian Hispanic/Latina patients.

Citation Format: Serrano-Gomez SJ, Sanabria MC, Hernández-Suarez GA, Garcia O, Silva C, Romero A, Mejía JC, Fejerman L, Antonia T, Miele L, Zabaleta J. Increased prevalence of luminal B subtype in Colombian women with breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-08-09.

French vertical-flow constructed wetlands in mountain areas: how do cold temperatures impact performances?

The French version of vertical-flow constructed wetlands (VFCWs) is characterized by treating directly raw wastewater on a first-stage filter. VFCW is a well developed technology with more than 3,500 plants in operation in France. However, VFCW performance may be affected under the low temperatures reached in mountain areas during winter. The effect of cold conditions over 12 plants, ranging from 75 to 1,900 person equivalent and from 680 to 1,500 m above sea level, was studied over 2 years. The plant hydraulic loads, and air and filter temperatures were continuously measured. In addition, 24-h flow proportional sampling, at each stage of treatment, was conducted in summer (as a reference) and winter. Online measurements of ammonium and nitrates were also analyzed to describe the nitrogen removal dynamics. Since no impact on chemical oxygen demand (COD), biochemical oxygen demand (BOD) and suspended solids removal was observed, the effect of cold temperatures on nitrification was further analyzed. Nitrogen removal was relatively unaffected during winter season. Significant effects were confirmed only for the second stage for loads above 10 gTKN/m²/d (TKN: total Kjeldahl nitrogen). Temperature profiles allowed analysis of the filter buffer capacity in terms of freezing. Under minimal air temperature of -19 °C, no critical operation was observed, although design and operation recommendations can be provided to ensure suitable plant performances.

New ideas in lung regeneration: a personal view from Estoril

10th ERS Lung Science Conference--rebuilding a diseased lung: repair and regeneration Estoril, Portugal, 30 March-1 April 2012 The 10th ERS Lung Science Conference, held in Estoril, Portugal, focused on rebuilding a diseased lung: repair and regeneration, seeking to understand, with some amount of precision, how the processes by which the vastly complex self-assembling, self-repairing machine that is a human lung actually develops from a few cells in the embryo, repairs itself or fails to and succumbs to disease. Thus, the major research themes focused on lung development, lung stem and progenitor cell populations, regenerative signaling mechanisms and tissue engineering and transplantation.

Volatile compounds and antioxidative activity of Porophyllum tagetoides extracts

Porophyllum tagetoides is an annual warm-weather herb that has an intense typical smell. Its leaves are commonly used in soup preparation and traditional medicine for treatment of inflammatory diseases. Its volatile compounds and antioxidant properties were evaluated in crude, aqueous and ethanol leaf extract and an oil emulsion using different antioxidant assays in vitro, such as: DPPH radical scavenging activity, redox potential, polyphenol content, reducing power and optical density. A high antioxidative activity was found when comparing leaves with stems. The crude extract from leaves showed a very high reducing power (2.88 ± 0.20 O.D.) and DPPH radical-scavenging activity (54.63 ± 4.80%), in concordance with a major concentration of vitamin C (23.97 ± 0.36 mg/100 g). Instead, the highest polyphenol content (264.54 ± 2.17 mg GAE/g of sample) and redox potential (561.23 ± 0.15 mV) were found by the ethanol and aqueous extract, respectively. Aldehydes and terpenes such as nonanal, decanal, trans-pineno, β-myrcene and D-limonene were the major volatiles found. This study suggests that Porophyllum tagetoides extracts could be used as antioxidants.

Cell-based therapies for lung disease

INTRODUCTION OR BACKGROUND

The adult lung is a complex organ whose large surface area interfaces extensively with both the environment and circulatory system. Yet, in spite of the high potential for exposure to environmental or systemic harm, epithelial cell turnover in adult lung is comparatively slow. Moreover, loss of lung function with advancing age is becoming an increasingly costly healthcare problem. Cell-based therapies stimulating endogenous stem/progenitor cells or supplying exogenous ones have therefore become a prime translational goal. Alternatively when lung repair becomes impossible, replacement with tissue-engineered lung is an attractive emerging alternative using a decellularized matrix or bioengineered scaffold.

SOURCES OF DATA

Endogenous and exogenous stem cells for lung therapy are being characterized by defining developmental lineages, surface marker expression, functions within the lung and responses to injury and disease. Seeding decellularized lung tissue or bioengineered matrices with various stem and progenitor cells is an approach that has already been used to replace bronchus and trachea in human patients and awaits further development for whole lung tissue.

AREAS OF AGREEMENT

Cellular therapies have clear potential for respiratory disease. However, given the surface size and complexity of lung structure, the probability of a single cellular population sufficing to regenerate the entire organ, as in the bone marrow, remains low. Hence, lung regenerative medicine is currently focused around three aims: (i) to identify and stimulate resident cell populations that respond to injury or disease, (ii) to transplant exogenous cells which can ameliorate disease and (iii) to repopulate decellularized or bioengineered lung matrix creating a new implantable organ.

AREAS OF CONTROVERSY

Lack of consensus on specific lineage markers for lung stem and progenitor cells in development and disease constrains transferability of research between laboratories and sources of cellular therapy. Furthermore, effectiveness of individual cellular therapies to correct gas exchange and provide other critical lung functions remains unproven. Finally, feasibility of autologous whole organ replacement has not been confirmed as a durable therapy. Growing points Cellular therapies for lung regeneration would be enhanced by better lineage tracing within the lung, the ability to direct differentiation of exogenous stem or progenitor cells, and the development of functional assays for cellular viability and regenerative properties. Whether endogenous or exogeneous cells will ultimately play a greater therapeutic role remains to be seen. Reducing the need for lung replacement via endogenous cell-mediated repair is a key goal. Thereafter, improving the potential of donor lungs in transplant recipients is a further area where cell-based therapies may be beneficial. Ultimately, lung replacement with autologous tissue-engineered lungs is another goal for cell-based therapy. Areas timely for developing research Defining 'lung stem or progenitor cell' populations in both animal models and human tissue may help. Additionally, standardizing assays for assessing the potential of endogenous or exogenous cells within the lung is important. Understanding cell-matrix interactions in real time and with biomechanical insight will be central for lung engineering. Cautionary note Communicating the real potential for cell-based lung therapy needs to remain realistic, given the keen expectations of patients with end-stage lung disease.

Oxidative dissolution of arsenopyrite by mesophilic and moderately thermophilic acidophiles

The purpose of this work was to determine solution- and solid-phase changes associated with the oxidative leaching of arsenopyrite (FeAsS) by Thiobacillus ferrooxidans and a moderately thermoacidophilic mixed culture. Jarosite [KFe(3)(SO(4))(2)(OH)(6)], elemental sulfur (S), and amorphous ferric arsenate were detected by X-ray diffraction as solid-phase products. The oxidation was not a strongly acid-producing reaction and was accompanied by a relatively low redox level. The X-ray diffraction lines of jarosite increased considerably when ferrous sulfate was used as an additional substrate for T. ferroxidans. A moderately thermoacidophilic mixed culture oxidized arsenopyrite faster at 45 degrees C than did T. ferroxidans at 22 degrees C, and the oxidation was accompanied by a nearly stoichiometric release of Fe and As. The redox potential was initially low but subsequently increased during arsenopyrite oxidation by the thermoacidophiles. Jarosite, S, and amorphous ferric arsenate were also formed under these conditions.

Health-related Quality of Life before and after a solid organ transplantation (kidney, liver, and lung) of four Catalonia hospitals

INTRODUCTION AND AIMS

It has been described that patients who receive a transplant display a better Health Related Quality of Life (HRQoL). Our objective was to describe the HRQoL before and after a solid organ transplantation, comparing results among various transplantations.

METHODS

This HRQoL study using the SF-36 was implemented before as well as at 3 and 12 months posttransplantation. Posttransplantation were compared with pretransplantation scores as well as with the general population.

RESULTS

One hundred sixty-two renal, 159 liver, and 58 lung candidates were included before transplantation, among whom there were 126 renal, 108 liver, and 22 lung recipients. The median age of all transplant recipients was 53 years with 68% men. The various transplant types began with different HRQoL: lung showed the worst, followed by the liver, and then renal. The scores of the SF-36 before and 3 months posttransplantation showed significant improvements, except for "Pair." At 12 versus 3 months, mental health was somewhat better for renal, and almost all dimensions showed significant improvement for liver and lung patients. All subjects showed clear improvements after transplantation.

CONCLUSION

All patients showed clear improvements after transplantation when mental health was compared with the general population, particularly lung transplant recipients who expressed the greatest improvement. However, they still showed deficits in physical health.

Lessons learned engaging Hispanic communities in cancer research

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Background: Community involvement is critical to advance cancer education and prevention in minority communities. Researchers must be knowledgeable of the target community's basic cultural beliefs and linguistic needs. This study sought to identify the best approach for conducting community based cancer research in South Texas Hispanic communities. We report our experiences and lessons learned with participants and site recruitment and retention. Methods: We introduced a community based, culturally relevant breast and cervical cancer screening and early detection program, Esperanza y Vida, to address barriers and disparities in four border communities (urban, rural, colonia, and small border town). These areas represent the diverse South Texas Mexican American population in terms of language use, immigration status, and length of time in the US. Within these communities we recruited a grassroots community organization, faith-based health center, rural hospital district, and federally qualified health center. Results: Focus groups were conducted with women and men to assess knowledge, attitudes, and beliefs about women's cancers. To successfully recruit participants, we implemented various techniques to engage the community and establish sustainable relationships. These included community health worker recruitment of community members, traditional recruitment (flyers, posters, word of mouth), key community and cultural leader support, and discussions with local groups and health organizations. We and our community partners identified and overcame investigator/community barriers (lack of community knowledge, community integration into the research process, community understanding of research methods, reluctance to develop innovative approaches). Consequently, participants are eager to remain with the program and are individually and collectively mobilizing others to create a sustainable and durable program. Conclusions: 1. Cultural leader engagement worked best for participant recruitment in the small border town and colonia settings, while key community leader engagement was most effective in the small city urban and rural settings. 2. Research/community partners must identify and discuss project barriers regardless of the fear of creating discordance to reach solutions.

No significant financial relationships to disclose.

Iron-plasma transmission measurements at temperatures above 150 eV

Measurements of iron-plasma transmission at 156+/-6 eV electron temperature and 6.9+/-1.7 x 10(21) cm(-3) electron density are reported over the 800-1800 eV photon energy range. The temperature is more than twice that in prior experiments, permitting the first direct experimental tests of absorption features critical for understanding solar interior radiation transport. Detailed line-by-line opacity models are in excellent agreement with the data.

Loss of bacterial diversity during antibiotic treatment of intubated patients colonized with Pseudomonas aeruginosa

Management of airway infections caused by Pseudomonas aeruginosa is a serious clinical challenge, but little is known about the microbial ecology of airway infections in intubated patients. We analyzed bacterial diversity in endotracheal aspirates obtained from intubated patients colonized by P. aeruginosa by using 16S rRNA clone libraries and microarrays (PhyloChip) to determine changes in bacterial community compositions during antibiotic treatment. Bacterial 16S rRNA genes were absent from aspirates obtained from patients briefly intubated for elective surgery but were detected by PCR in samples from all patients intubated for longer periods. Sequencing of 16S rRNA clone libraries demonstrated the presence of many orally, nasally, and gastrointestinally associated bacteria, including known pathogens, in the lungs of patients colonized with P. aeruginosa. PhyloChip analysis detected the same organisms and many additional bacterial groups present at low abundance that were not detected in clone libraries. For each patient, both culture-independent methods showed that bacterial diversity decreased following the administration of antibiotics, and communities became dominated by a pulmonary pathogen. P. aeruginosa became the dominant species in six of seven patients studied, despite treatment of five of these six with antibiotics to which it was sensitive in vitro. Our data demonstrate that the loss of bacterial diversity under antibiotic selection is highly associated with the development of pneumonia in ventilated patients colonized with P. aeruginosa. Interestingly, PhyloChip analysis demonstrated reciprocal changes in abundance between P. aeruginosa and the class Bacilli, suggesting that these groups may compete for a similar ecological niche and suggesting possible mechanisms through which the loss of microbial diversity may directly contribute to pathogen selection and persistence.

Expression of TTF-1 and cytokeratins in primary and secondary epithelial lung tumours: correlation with histological type and grade

AIMS

To assess cytokeratin (CK) and thyroid transcription factor (TTF)-1 expression in primary epithelial lung tumours by comparison with non-pulmonary carcinomas and to correlate it with their histological type and grade.

METHODS AND RESULTS

Immunohistochemistry using antibodies against CKs 5/6, 7, 19, 20 and TTF-1 was applied to 165 primary and 37 secondary epithelial lung tumours. CK5/6 is a sensitive and specific marker of lung squamous carcinomas being positive in 100% of cases. CK7 is a common marker of primary lung adenocarcinomas (100% of cases) but with a lower specificity since it is also observed in other primary lung carcinomas (70% of large-cell neuroendocrine carcinomas, 40% of large-cell carcinomas, 23% of squamous carcinomas) but also in 27% of non-pulmonary adenocarcinomas. Addition of an anti-CK20 may be useful to prove or disprove the pulmonary origin of an adenocarcinoma when there is a history of colon cancer. CK19 is ubiquitous but a predominant or exclusive 'dot-like' pattern is very suggestive of high-grade neuroendocrine carcinoma. TTF-1 is a very sensitive and specific marker to document the pulmonary origin of an adenocarcinoma if a thyroid origin is excluded. Its expression in neuroendocrine lung tumours depends on the tumour grade.

CONCLUSIONS

Immunohistochemical expression of CKs and TTF-1 may be correlated with histological type and grade of lung primary epithelial tumours and may allow them to be distinguished from non-pulmonary carcinomas.

Oxidative dissolution of chalcopyrite by Acidithiobacillus ferrooxidans analyzed by electrochemical impedance spectroscopy and atomic force microscopy

The microbiological leaching of chalcopyrite (CuFeS(2)) is of great interest because of its potential application to many CuFeS(2)-rich ore materials. However, the efficiency of the microbiological process is very limited because this mineral is one of the most refractory to bacterial attack. Knowledge of bacterial role during chalcopyrite oxidation is very important in order to improve the efficiency of bioleaching operation. The oxidative dissolution of a massive chalcopyrite electrode by Acidithiobacillus ferrooxidans was evaluated by electrochemical impedance spectroscopy (EIS) and atomic force microscopy (AFM). A massive chalcopyrite electrode was utilized in a Tait-type electrochemical cell in acid medium for different immersion times in the presence or absence of bacterium. The differences observed in the impedance diagrams were correlated with the adhesion process of bacteria on the mineral surface.

Assessment of anaerobic sewage sludge quality for agricultural application after metal bioleaching

The effects of metal bioleaching on nutrient solubilization, especially nitrogen and phosphorous, from anaerobically-digested sewage sludge were investigated in this work. The assessment of the sanitary quality of the anaerobic sludge after bioleaching was also carried out by enumerating indicator (total coliforms, fecal coliforms, and fecal streptococci) and total heterotrophic bacteria. The experiments of bioleaching were performed using indigenous sulphur-oxidizing bacteria (Thiobacillus spp.) as inoculum and samples of anaerobically-digested sludge. Nitrogen and phosphorous solubilization from sewage sludge was assessed by measuring, respectively, the concentration of Total Kjeldahl Nitrogen, ammonia, nitrate/nitrite, and soluble and total phosphorous before and after the bioleaching assays. At the end of the experiment, after 4 days of incubation (final pH of 1.4), the following metal solubilization yields were obtained: zinc, 91%; nickel, 87%; copper, 79%; lead, 52%; and chromium, 42%. As a result of sludge acidification, the viable counts of selected indicator bacteria were decreased to below the detection limit (4 x 10(3) cfu 100 ml(-1)), followed by an increase in the mineral fraction of nitrogen (from 6 to 10%) and in the soluble fraction of phosphorous (from 15 to 30%). Although some loss of sludge nutrients can occur during solid-liquid separation following bioleaching, its beneficial effects as metal removal and reduction of pathogenic bacteria are sufficient to consider the potential of this treatment before sludge disposal onto agricultural fields.

Molecular characterization of Acidithiobacillus ferrooxidans and A. thiooxidans strains isolated from mine wastes in Brazil

Nineteen strains of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans, including 12 strains isolated from coal, copper, gold and uranium mines in Brazil, strains isolated from similar sources in other countries and the type strains of the two species were characterized together with the type strain of A. caldus by using a combination of molecular systematic methods, namely ribotyping, BOX- and ERIC-PCR and DNA-DNA hybridization assays. Data derived from the molecular fingerprinting analyses showed that the tested strains encompassed a high degree of genetic variability. Two of the Brazilian A. ferrooxidans organisms (strains SSP and PCE) isolated from acid coal mine waste and uranium mine effluent, respectively, and A. thiooxidans strain DAMS, isolated from uranium mine effluent, were the most genetically divergent organisms. The DNA-DNA hybridization data did not support the allocation of Acidithiobacillus strain SSP to the A. ferrooxidans genomic species, as it shared only just over 40% DNA relatedness with the type strain of the species. Acidithiobacillus strain SSP was not clearly related to A. ferrooxidans in the 16S rDNA tree.

A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean area

In this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1.2) identified by us and reported in previous studies, whose geographic distribution and antiquity appear to be compatible with the Neolithic spread of farmers. Here, we set network 1.2 in the Y-chromosomal phylogenetic tree, date it with respect to other lineages associated with the same movements by other authors, examine its diversity by means of tri- and tetranucleotide loci and discuss the implications in reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny within HG 9 (Rosser et al. 2000), with the deepest branching defined by alleles T (Haplogroup Eu10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1.2. Population distributions of HG 9 and network 1.2 show that their occurrence in the surveyed area is not due to the spread of people from a single parental population but, rather, to a process punctuated by at least two phases. Our data identify the wide area of the Balkans, Aegean and Anatolia as the possible homeland harbouring the largest variation within network 1.2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, with a high rate of male gene flow in the Turkish-Greek area.