Polycaprolactone- and polycaprolactone/ceramic-based 3D-bioplotted porous scaffolds for bone regeneration: A comparative study.

One of the critical challenges that scaffolding faces in the organ and tissue regeneration field lies in mimicking the structure, and the chemical and biological properties of natural tissue. A high-level control over the architecture, mechanical properties and composition of the materials in contact with cells is essential to overcome such challenge. Therefore, definition of the method, materials and parameters for the production of scaffolds during the fabrication stage is critical. With the recent emergence of rapid prototyping (RP), it is now possible to create three-dimensional (3D) scaffolds with the essential characteristics for the proliferation and regeneration of tissues, such as porosity, mechanical strength, pore size and pore interconnectivity, and biocompatibility. In this study, we employed 3D bioplotting, a RP technology, to fabricate scaffolds made from (i) pure polycaprolactone (PCL) and (ii) a composite based on PCL and ceramic micro-powder. The ceramics used for the composite were bovine bone filling Nukbone® (NKB), and hydroxyapatite (HA) with 5%, 10% or 20% wt. CONTENT: The scaffolds were fabricated in a cellular lattice structure (i.e. meshing mode) using a 0/90° lay down pattern with a continuous contour filament in order to achieve interconnected porous reticular structures. We varied the temperature, as well as injection speed and pressure during the bioplotting process to achieve scaffolds with pore size ranging between 200 and 400µm and adequate mechanical stability. The resulting scaffolds had an average pore size of 323µm and an average porosity of 32%. Characterization through ATR-FTIR revealed the presence of the characteristic bands of hydroxyapatite in the PCL matrix, and presented an increase of the intensity of the phosphate and carbonyl bands as the ceramic content increased. The bioplotted 3D scaffolds have a Young's modulus (E) in the range between 0.121 and 0.171GPa, which is compatible with the modulus of natural bone. PCL/NKB scaffolds, particularly 10NKBP (10% NKB wt.) exhibited the highest proliferation optical density, demonstrating an evident osteoconductive effect when cultured in Dulbecco's Modified Eagle Medium (DMEM). Scanning electron microscopy (SEM) confirmed osteoblast anchorage to all composite scaffolds, but a low adhesion to the all-PCL scaffold, as well as cell proliferation. The results from this study demonstrate the potential of PCL/NKB 3D bioplotted scaffolds as viable platforms to enable osseous tissue formation, which can be used in several tissue engineering applications, including improvement of bone tissue regeneration.

Trypsin as enhancement in cyclical tracheal decellularization: Morphological and biophysical characterization.

There are different types of tracheal disorders (e.g. cancer, stenosis and fractures). These can cause respiratory failure and lead to death of patients. Several attempts have been made for trachea replacement in order to restore the airway, including anastomosis and implants made from synthetic or natural materials. Tracheal allotransplantation has shown high rejection rates, and decellularization has emerged as a possible solution. Decellularization involves the removal of antigens from cells in the organ or tissue, leaving a matrix that can be used as 3D cell-scaffold. Although this process has been used for tracheal replacement, it usually takes at least two months and time is critical for patients with tracheal disorders. Therefore, there is necessary to develop a tracheal replacement process, which is not only effective, but also quick to prepare. The aim of this research was to develop a faster trachea decellularization protocol using Trypsin enzyme and Ethylenediaminetetraacetic acid (EDTA) as decellularization agents. Three protocols of cyclic trachea decellularization (Protocols A, B, and C) were compared. Following Protocol A (previously described in the literature), 15 consecutive cycles were performed over 32 days. Protocol B (a variation of Protocol A) ­ EDTA being added ­ with 15 consecutive cycles performed over 60 days. Finally, Protocol C, with the addition of Trypsin as a decellularization agent, 5 consecutive cycles being performed over 10 days. For the three protocols, hematoxylin­eosin (H&E) staining and DNA residual content quantification were performed to establish the effectiveness of the decellularization process. Scanning Electron Microscopy (SEM) was used to observe the changes in porosity and microarrays. To evaluate the structural matrices integrity, Thermogravimetric Analysis (TGA) and biomechanical test were used. None of the protocols showed significant alteration or degradation in the components of the extracellular matrix (ECM). However, in Protocol C, more cellular components were removed in less time, making it the most efficient process. In addition, the cell tracking and viability was evaluated with chondrocytes seeding on the scaffold obtained by Protocol C, which showed an adequate cell scaffolding ability of this matrix.

Thermoluminescent characteristics of synthetic hydroxyapatite (SHAp).

This paper presents the experimental results of the thermoluminescent (TL) characteristics of synthetic hydroxyapatite (SHAp) obtained by the sol-gel method. For preparation of the SHAp powders, phosphorus pentoxide (P2O5) and calcium nitrate tetrahydrated (Ca(NO3)2-4H2O) were used. The powders obtained were submitted at different temperatures. The structural and morphological characterization were carried out using X-ray diffraction (XRD) and scanning electron microscopy techniques. TL glow curve exhibited two peaks centered at around 200 °C and 300 °C. TL response of SHAp as a function of gamma absorbed dose was linear over a wide dose range. Fading of the storage information in the samples irradiated was also studied. The experimental results show that the synthetic hydroxyapatite obtained by the sol-gel method may have used in gamma radiation dosimetry applications.

Characterization of Bone Cements Prepared with Either Hydroxyapatite, α-TCP or Bovine Bone / Caracterización de cementos óseos preparados con hidroxiapatita, α-TCP o hueso bovino

In this work, we report the preparation of bone cements by using methyl methacrylate (MMA) as a base monomer and either hydroxyapatite (HA), alpha tricalcium phosphate (α-TCP) or bovine bone particles as bioactive fillers. In general, it was observed that curing times increased by the addition of any of these fillers (from 4 to 6.7 min). Maximum temperatures decrease slightly by the addition of 20 wt.% of either α-TCP or bovine bone (80.3°C and 73.2°C respectively) but it did not change by the addition of HA (84.3°C) with respect to PMMA only bone cement used as control. Residual monomer content was lower than 4% in the bioactive bone cements. By using α-TCP or bovine bone compressive strength increased with respect to the unfilled bone cement but it was reduced when HA was used. However, all these formulations fulfill the 70 MPa required for bone cement use. Flexural strength was increased by using either a-TCP o bovine bone but the addition of HA decreased this properties compared to the base bone cement. However, the minimum flexural strength (50 MPa) was fulfilled only in those experimental formulations containing low amounts of α-TCP. The minimum tensile strength (30 MPa) was satisfied by all formulations but it was always lower than the exhibited by the unfilled bone cement.

Este trabajo reporta la preparación de cementos óseos utilizando metacrilato de metilo (MMA) como monómero base y rellenos bioactivos tales como hidroxiapatita (HA), fosfato tricálcico alfa (α-TCP) o hueso bovino. En general, los tiempos de curado aumentaron con la inclusión de estos refuerzos (de 4 hasta 6.7 min). La temperatura máxima alcanzada durante la polimerización del cemento disminuyó ligeramente al adicionar 20% de α-TCP o hueso bovino (80.3°C y 73.2°C respectivamente) y se mantuvo sin cambio en las formulaciones con HA (84.3°C) con respecto al control de solo PMMA. El contenido de monómero residual en los cementos bioactivos fue menor al 4%. La presencia de α-TCP o hueso bovino aumentó la resistencia a la compresión del cemento base y la adición de HA la disminuyó, cumpliendo en todos los casos con la resistencia mínima a la compresión (70 MPa) sugerida para su uso como cemento óseo. La adición de α-TCP o hueso bovino aumentó la resistencia a la flexión del cemento base pero la adición de HA la redujo aunque el requerimiento mínimo de resistencia a la flexión (50 MPa) fue cumplido solamente al usar concentraciones bajas de α-TCP. La resistencia tensil mínima (30 MPa) fue satisfecha por todas las formulaciones aunque siempre fue menor que la exhibida por el cemento base.

Validity and reliability of the MSKCC Bowel Function instrument in a sample of Italian rectal cancer patients.

AIMS: The purpose of this study was to translate the Memorial Sloan Kettering Cancer Centre (MSKCC) Bowel Function Instrument into Italian and to test its psychometric validity and reliability in a sample of Italian rectal cancer patients. METHODS: The MSKCC questionnaire was translated into Italian using a standard procedure of double-back translation. Construct validity was tested using a factor analysis and internal reliability was estimated using the Cronbach's alpha coefficient. Concurrent validity was determined by correlations with European Organisation for Research and Treatment of Cancer QLQ-C30 and QLQ-CR38 quality of life scales. A non-parametric analysis of variance was used to establish the discriminant validity of the questionnaire. Test-retest reliability was assessed using the intra-class correlation coefficient. RESULTS: 124 rectal cancer patients participated in the validation study. The number of missing items was 2.2%. The factorial structure was found to be quite similar to the original one and the internal reliability was 0.7 for urgency, 0.6 for frequency, and 0.7 for dietary subscale. The test-retest reliability was acceptable with one exception: the dietary subscale showed a low reproducibility (ICC = 0.4). All three subscales showed a significant correlation with the QLQ-C30 and QLQ-CR38 domains and were able to discriminate several groups of clinical relevance. CONCLUSIONS: The Italian version of the MSKCC Bowel Function Instrument shows acceptable psychometric properties and can be considered a valuable and specific instrument to assess bowel functions in rectal cancer patients, both for research purposes and in clinical practise.

Evidence and research perspectives for surgeons in the European Rectal Cancer Consensus Conference (EURECA-CC2).

PURPOSE: Although surgery remains the most important treatment of rectal cancer, the management of this disease has evolved to become more multidisciplinary to offer the best clinical outcome. The International Conference on Multidisciplinary Rectal Cancer Treatment: Looking for an European Consensus' (EURECA-CC2) had the duty to identify the degree of consensus that could be achieved across a wide range of topics relating to the management of rectal cancer helping shape future programs, investigational protocols and guidelines for staging and treatment throughout Europe. MATERIALS AND METHODS: Consensus was achieved using the Delphi method. Eight chapters were identified: epidemiology, diagnostics, pathology, surgery, radiotherapy and chemotherapy, treatment toxicity and quality of life, follow-up, and research questions. Each chapter was subdivided by topic, and a series of statements were developed. Each committee member commented and voted, sentence by sentence three times. Sentences which did not reach agreement after voting round #2 were openly debated during the Conference in Perugia (Italy) December 2008. The Executive Committee scored percentage consensus based on three categories: "large consensus", "moderate consensus", "minimum consensus". RESULTS: The total number of the voted sentences was 207. Of the 207, 86% achieved large consensus, 13% achieved moderate consensus, and only 3 (1%) resulted in minimum consensus. No statement was disagreed by more than 50% of members. All chapters were voted on by at least 75% of the members, and the majority was voted on by 85%. CONCLUSIONS: This Consensus Conference represents an expertise opinion process that may help shape future programs, investigational protocols, and guidelines for staging and treatment of rectal cancer throughout Europe. In spite of substantial progress, many research challenges remain.

The role of multimodality treatment in M0 rectal cancer: evidence and research.

In the last two decades we have seen major advances in the strategy of the treatment of rectal cancer. Important studies were published to confirm the role of imaging MRI in the treatment plan and in detecting the prognostic factors, the improved outcome of the new surgical technique based on total mesorectal excision and the combined treatments. Many studies demonstrated that MRI is equivalent to histology in measurement of extramural depth, is also highly accurate in staging advanced rectal cancer, in the assessment of mesorectal fascia infiltration and to distinguish cT3 from cT4, in the measuring the distance from the anorectal ring. With the introduction of total mesorectal excision the local recurrence rate is dramatically reduced, especially in selected centres. Preoperative radiotherapy +/- in combination with chemotherapy still reduces this rates respect to only surgery or postoperative treatment. In this time of changing therapeutic approaches, a common standard for large heterogeneous patient groups will likely be substituted by more individualised therapies. It will depend from new evidence of more tailored diagnosis, surgery, radiotherapy and chemotherapy.

Could the surgeon trust to radiotherapy help in rectal cancer?

When the surgeon analyzes the ongoing literature on the evidence of the neoadjuvant approaches to rectal cancer finds a true paradox: from one side they seem to offer a relative less relevant contribute through the time, in fact whereas in the Swedish trial preoperative radiation yielded a significant improvement of local control and survival, after the introduction of TME the contribution of preoperative chemoradiation is relegate to local control with no or poor influence on survival, even if the absolute 5-year survival rate moved from 40% of the '70 to 60-65% of the latest years. From other side the growing evidence of an incidence of pCR approaching to 30%, seems to identify a subset of patients with more favourable prognosis to neoadjuvant treatments. Furthermore, the overall evidence that 30-35% of rectal cancer patients treated with multimodality therapy still die from cancer namely by distant metastases in spite of the 4-8% of absolute benefit of adjuvant 5Fu based adjuvant chemotherapy, seems to vanish the efforts of the further optimization of the local treatments (surgery and radiotherapy) and of the ongoing modality of delivery the chemotherapeutic agents. We would like to address the main evidences from the literature and the main uncertainties that the surgeon could face to propose a combined treatment to his rectal cancer patient.

A web service-based Grid portal for Edgebreaker compression.

BACKGROUND: In health applications, and elsewhere, 3D data sets are increasingly accessed through the Internet. To reduce the transfer time while maintaining an unaltered 3D model, adequate compression and decompression techniques are needed. Recently, Grid technologies have been integrated with Web Services technologies to provide a framework for interoperable application-to-application interaction. OBJECTIVES: The paper describes an implementation of the Edgebreaker compression technique exploiting web services technology and presents a novel approach for using such services in a Grid Portal. The Grid portal, developed at the CACT/ISUFI of the University of Lecce, allows the processing and delivery of biomedical images (CT--computerized tomography--and MRI--magnetic resonance images) in a distributed environment, using the power and security of computational Grids. METHODS: The Edgebreaker Compression Web Service has been deployed on a Grid portal and allows compressing and decompressing 3D data sets using the Globus toolkit GSI (Globus Security Infrastructure) protocol. Moreover, the classical algorithm has been modified extending the compression to files containing more than one object. RESULTS AND CONCLUSIONS: An implementation of the Edgebreaker compression technique and related experimental results are presented. A novel approach for using the compression web service in a Grid portal allowing storing and preprocessing of huge 3D data sets, and subsequent efficient transmission of results for remote visualization is also described.

Audiometric findings in petrochemical workers exposed to noise and chemical agents.

This study investigated the occurrence of hearing loss among workers of a petrochemical industry during a period of five years. The records of environmental noise and solvents measurements and the results of annual audiometry performed by the company were examined. The audiometric results of workers from olefin operational areas 1 and 2 and aromatic plant areas exposed to solvents and noise and utility area workers exposed only to noise were analyzed for the standard threshold shift (STS). Despite the low exposures to solvents and a moderate exposure to noise, 45.3% of workers had hearing losses and 29.6% had STS.

[Nurses' work in Peru: origin and social conditions]. / O trabalho da enfermeira no Peru: gênese e constituição social.

The study aimed at reviewing the history of the genesis and social formation of nurses work in Peru in order to understand it according to women's social situation in the context of a masculine society organized under capitalism. Thus, nursing formation was influenced by the Nightingale School and the exercise of the Peruvian nurses was characterized by the reproduction of social functions that are historically feminine, with a knowledge and practice subordinated to medical knowledge, that is mainly directed by a masculine ideology.

[Gender and the working woman in Peru]. / Genero y trabajo femenino en el Peru.

This study identifies the peruvian women's labor conditions and its social and historical determinants due to social class, race and gender differences that influence women subordination in social structure. Bibliographic review shows that the peruvian working woman situation experienced great and deep changes in time, as a result of ideological and cultural patriarchal patterns that culminated in the current capitalist society.