Validation of an in vivo transit dosimetry algorithm using Monte Carlo simulations and ionization chamber measurements.

PURPOSE: Transit dosimetry is a safety tool based on the transit images acquired during treatment. Forward-projection transit dosimetry software, as PerFRACTION, compares the transit images acquired with an expected image calculated from the DICOM plan, the CT, and the structure set. This work aims to validate PerFRACTION expected transit dose using PRIMO Monte Carlo simulations and ionization chamber measurements, and propose a methodology based on MPPG5a report. METHODS: The validation process was divided into three groups of tests according to MPPG5a: basic dose validation, IMRT dose validation, and heterogeneity correction validation. For the basic dose validation, the fields used were the nine fields needed to calibrate PerFRACTION and three jaws-defined. For the IMRT dose validation, seven sweeping gaps fields, the MLC transmission and 29 IMRT fields from 10 breast treatment plans were measured. For the heterogeneity validation, the transit dose of these fields was studied using three phantoms: 10 , 30 , and a 3 cm cork slab placed between 10 cm of solid water. The PerFRACTION expected doses were compared with PRIMO Monte Carlo simulation results and ionization chamber measurements. RESULTS: Using the 10 cm solid water phantom, for the basic validation fields, the root mean square (RMS) of the difference between PerFRACTION and PRIMO simulations was 0.6%. In the IMRT fields, the RMS of the difference was 1.2%. When comparing respect ionization chamber measurements, the RMS of the difference was 1.0% both for the basic and the IMRT validation. The average passing rate with a γ(2%/2 mm, TH = 20%) criterion between PRIMO dose distribution and PerFRACTION expected dose was 96.0% ± 5.8%. CONCLUSION: We validated PerFRACTION calculated transit dose with PRIMO Monte Carlo and ionization chamber measurements adapting the methodology of the MMPG5a report. The methodology presented can be applied to validate other forward-projection transit dosimetry software.

Telemedicine Beyond Borders: A Mixed-Methods Approach to Understanding Cross-National Usage Intention.

Introduction: Drawing on the Unified Theory of Acceptance and Use of Technology 2 and the Diffusion of Innovation Theory, this article investigates the adoption of telemedicine services from a patient perspective in Germany, Spain, and the United States using a mixed-methods approach. Digital health technologies have the potential to improve access to care and to alleviate the burden on traditional health care systems and are becoming more integrated into everyday medicine. Therefore, understanding the factors that impact patients' intentions to use telemedicine is crucial to ensure successful development. Methods: Based on 1,200 surveys collected in Germany, Spain, and the United States, structural equation modeling (IBM SPSS Amos 24) is employed to test the hypotheses. The article also explores how age and gender moderate the proposed relationships. Results: Seven out of the 10 hypotheses (performance expectancy, hedonic motivation, habit, relative advantage, and perceived security) are found to be positive, direct, and statistically significant. Furthermore, findings suggest stronger effects for telemedicine usage intention for younger female users than their male counterparts. Discussion: With digital health technologies becoming more prevalent, the outcomes of this study can endorse the development of effective strategies to promote the adoption of telemedicine, ultimately improving access to care and contributing to the advancement of and modern health care.

New Insights into the Pro-Inflammatory and Osteoclastogenic Profile of Circulating Monocytes in Osteoarthritis Patients.

Osteoarthritis (OA) is a degenerative condition of the articular cartilage with chronic low-grade inflammation. Monocytes have a fundamental role in the progression of OA, given their implication in inflammatory responses and their capacity to differentiate into bone-resorbing osteoclasts (OCLs). This observational-experimental study attempted to better understand the molecular pathogenesis of OA through the examination of osteoclast progenitor (OCP) cells from both OA patients and healthy individuals (25 OA patients and healthy samples). The expression of osteoclastogenic and inflammatory genes was analyzed using RT-PCR. The OA monocytes expressed significantly higher levels of CD16, CD115, TLR2, Mincle, Dentin-1, and CCR2 mRNAs. Moreover, a flow cytometry analysis showed a significantly higher surface expression of the CD16 and CD115 receptors in OA vs. healthy monocytes, as well as a difference in the distribution of monocyte subsets. Additionally, the OA monocytes showed a greater osteoclast differentiation capacity and an enhanced response to an inflammatory stimulus. The results of this study demonstrate the existence of significant differences between the OCPs of OA patients and those of healthy subjects. These differences could contribute to a greater understanding of the molecular pathogenesis of OA and to the identification of new biomarkers and potential drug targets for OA.

Gamma passing rates of daily EPID transit images correlate to PTV coverage for breast cancer IMRT treatment plans.

PURPOSE: The use of the transit image obtained with the electronic portal-imaging device (EPID) is becoming an extended method to perform in-vivo dosimetry. The transit images acquired during each fraction can be compared with a predicted image, if available, or with a baseline image, usually the obtained in the first fraction. This work aims to study the dosimetric impact of the failing fractions and to evaluate the appropriateness of using a baseline image in breast plans. MATERIAL AND METHODS: Twenty breast patients treated in a Halcyon were retrospectively selected. For each patient and fraction, the treatment plan was calculated over the daily CBCT image. For each fraction, the differences respect to the treatment plan values of OARs and PTV dosimetric parameters were analyzed: ΔDmean , ΔD95%, ΔD98%, ΔD2%, ΔV36Gy, ΔV38.5Gy, and ΔV43.5Gy. Daily fractions were ranked according to the differences found in the dosimetric parameters between the treatment plan and the daily CBCT to establish the best fraction. The daily transit images acquired in every fraction were compared to the first fraction using the global gamma index with the Portal Dosimetry tool. The comparison was repeated using the best fraction image as a baseline. We assessed the correlation of the dosimetric differences obtained from the CBCT images-based treatment plans with the gamma index passing rates obtained using first fraction and best fraction as baseline. RESULTS: Average values of -11.6% [-21.4%, -3.3%] and -3.2% [-1.0%, -10.3%] for the ∆PTVD98% and ∆PTVD95% per every 10% decrease in the passing rate were found, respectively. When using the best fraction as baseline patients were detected with failing fractions that were not detected with the first fraction as baseline. CONCLUSION: The gamma passing rates of daily transit images correlate with the coverage loss parameters in breast IMRT plans. Using first fraction image as baseline can lead to the non-detectability of failing fractions.

Extracorporeal photopheresis in paediatric patients: A retrospective comparison between different 'off-line' protocols.

BACKGROUND AND OBJECTIVES: Extracorporeal photopheresis (ECP) has been shown to be an effective treatment for graft-versus-host disease (GvHD). However, information regarding lymphocyte collection for ECP in children is limited. The aim of this study was to analyse and compare lymphocyte collection for ECP in children using different devices and protocols. Moreover, we have studied both safety and variables of the infused product related to treatment efficacy. PATIENTS AND METHODS: This was a retrospective study of 91 patients who underwent 1524 apheresis procedures with either the COBE Spectra or Spectra Optia system. The comparison study between the Optia protocols (MNC and CMNC) was prioritized. We analysed 578 procedures using the Optia blood cell separator: 204 and 374 using the MNC and the CMNC protocol, respectively. RESULTS: The Optia CMNC protocol showed better collection efficiency, with increased lymphocyte collection per kg of body weight (p < 0.001). On multivariate analysis, the type of protocol showed no relationship with haematocrit or platelet loss. Most procedures were well-tolerated, with the most frequent adverse events related to venous access (21.7%). Seventy-one percent of patients had either partial or complete clinical GvHD response. In the multivariate model, only two variables were associated with a better response to ECP, younger age and a greater increase of B lymphocytes after treatment. CONCLUSION: Lymphocyte collection for ECP is well-tolerated in most children, achieving complete or partial response in more than half of GvHD patients. CMNC is the optimal software to perform lymphocyte collection in children.

Connection between Mesenchymal Stem Cells Therapy and Osteoclasts in Osteoarthritis.

The use of mesenchymal stem cells constitutes a promising therapeutic approach, as it has shown beneficial effects in different pathologies. Numerous in vitro, pre-clinical, and, to a lesser extent, clinical trials have been published for osteoarthritis. Osteoarthritis is a type of arthritis that affects diarthritic joints in which the most common and studied effect is cartilage degradation. Nowadays, it is known that osteoarthritis is a disease with a very powerful inflammatory component that affects the subchondral bone and the rest of the tissues that make up the joint. This inflammatory component may induce the differentiation of osteoclasts, the bone-resorbing cells. Subchondral bone degradation has been suggested as a key process in the pathogenesis of osteoarthritis. However, very few published studies directly focus on the activity of mesenchymal stem cells on osteoclasts, contrary to what happens with other cell types of the joint, such as chondrocytes, synoviocytes, and osteoblasts. In this review, we try to gather the published bibliography in relation to the effects of mesenchymal stem cells on osteoclastogenesis. Although we find promising results, we point out the need for further studies that can support mesenchymal stem cells as a therapeutic tool for osteoclasts and their consequences on the osteoarthritic joint.

Extracellular Vesicles Do Not Mediate the Anti-Inflammatory Actions of Mouse-Derived Adipose Tissue Mesenchymal Stem Cells Secretome.

Adipose tissue represents an abundant source of mesenchymal stem cells (MSC) for therapeutic purposes. Previous studies have demonstrated the anti-inflammatory potential of adipose tissue-derived MSC (ASC). Extracellular vesicles (EV) present in the conditioned medium (CM) have been shown to mediate the cytoprotective effects of human ASC secretome. Nevertheless, the role of EV in the anti-inflammatory effects of mouse-derived ASC is not known. The current study has investigated the influence of mouse-derived ASC CM and its fractions on the response of mouse-derived peritoneal macrophages against lipopolysaccharide (LPS). CM and its soluble fraction reduced the release of pro-inflammatory cytokines, adenosine triphosphate and nitric oxide in stimulated cells. They also enhanced the migration of neutrophils or monocytes, in the absence or presence of LPS, respectively, which is likely related to the presence of chemokines, and reduced the phagocytic response. The anti-inflammatory effect of CM may be dependent on the regulation of toll-like receptor 4 expression and nuclear factor-κB activation. Our results demonstrate the anti-inflammatory effects of mouse-derived ASC secretome in mouse-derived peritoneal macrophages stimulated with LPS and show that they are not mediated by EV.

Food lipid oxidation under gastrointestinal digestion conditions: A review.

Unravelling the relationship between food and health requires a more in-depth knowledge of the various changes occurring in the gastrointestinal tract during digestion and which may ultimately affect the nutritional quality and safety of ingested food lipids before absorption into the bloodstream. In this context, this review deals with the oxidation process of food lipids under digestive conditions and the studies carried out on this topic using different digestion models: in vitro, in vivo or ex vivo, static or dynamic, and including one, two and/or three digestive phases (oral, gastric and duodenal). These studies have contributed to clarifying the occurrence and extent of lipid degradation under such a particular environment, many of them also highlighting the factors affecting the advance or delay of the oxidation of dietary lipids during digestion, like: food lipid content, unsaturation degree and initial oxidative status; the presence in the food bolus of compounds showing antioxidant activity (polyphenols, tocopherols…) either added or naturally present; the presence in the food bolus of proteins (including iron or not); food technological or culinary processings (salting, smoking, cooking…), among others. Likewise, the methodologies employed to study lipid oxidation under digestive conditions are also summarized and future research perspectives are discussed.

Positive and Useful Voices in Patients With Schizophrenia: Prevalence, Course, Characteristics, and Correlates.

Auditory verbal hallucinations (AVHs) in schizophrenia have been characterized by their negative emotional valence. However, positive hallucinations have also been described. The objective of the current study is to explore the prevalence, course, characteristics, and associations of positive and useful voices. The Positive and Useful Voices Inquiry and some clinical and functioning instruments were administered to a sample of 68 patients with schizophrenia or schizoaffective disorder presenting with AVHs. Both the lifetime and current prevalences of positive and useful voices were high. Although AVHs tended to remain stable, there was a trend to decrease over time. The strongest positive attributions of such voices were that they help patients to feel important, amuse them, and help them to conduct their studies and carry out their profession. They seem to be mainly related to more grandiosity and to worse general functioning. Interference with biological and psychological treatments and the need for personalized formulations in patients with auditory hallucinations are discussed.

Assessment of Soybean Oil Oxidative Stability from Rapid Analysis of its Minor Component Profile.

The minor components of vegetable oils are important for their oxidative stability. In order to know to what extent they can influence oil behaviour under oxidative conditions, two commercial soybean oils, one virgin and the other refined, both with very similar compositions in acyl groups but differing in their minor component profiles, were subjected to accelerated storage conditions. They were characterized by 1H nuclear magnetic resonance (NMR) and direct immersion solid-phase microextraction coupled to gas chromatography/mass spectrometry (DI-SPME-GC/MS), while oil oxidation was monitored by 1H-NMR. The lower levels of tocols and sterols in the virgin oil, together with its higher free fatty acid content when compared to the refined one, result in a lower oxidative stability. This is deduced from faster degradation of acyl groups and earlier generation of hydroperoxides, epoxides, and aldehydes in the virgin oil. These findings reveal that commercial virgin soybean oil quality is not necessarily higher than that of the refined type, and that a simple and rapid analysis of oil minor components by DI-SPME-GC/MS would enable one to establish quality levels within oils originating from the same plant species and similar unsaturation level regarding composition in potentially bioactive compounds and oxidative stability.

Influence of minor components on lipid bioaccessibility and oxidation during in vitro digestion of soybean oil.

BACKGROUND: Minor components of edible oils could influence their evolution during in vitro digestion. This might affect the bioaccessibility of lipid nutrients and the safety of the ingested food. Bearing this in mind, the evolution of virgin and refined soybean oils, which are very similar in acyl group composition, has been studied throughout in vitro digestion using 1 H nuclear magnetic resonance (NMR) and solid-phase microextraction-gas chromatography /mass spectrometry, focusing on lipolysis and oxidation reactions. The fate of γ-tocopherol, the main antioxidant present in soybean oil, has also been analyzed with 1 H NMR. RESULTS: There were no noticeable differences in lipolysis between the two oils that were studied. The extent of oxidation during digestion, which was very low in both cases, was slightly higher in the virgin type, which showed lower tocopherols and squalene concentrations than the refined one, together with a considerable abundance of free fatty acids. This can be deduced both from the appearance after digestion of conjugated hydroperoxy- and hydroxy-dienes only in the virgin oil, and from its higher levels of volatile aldehydes and 2-pentyl-furan. Under in vitro digestion conditions, the formation of epoxides seemed to be favored over other oxidation products. Finally, although some soybean oil essential nutrients like polyunsaturated fatty acids exhibited no significant degradation after digestion, γ-tocopherol concentration diminished during this process, especially in the virgin oil. CONCLUSION: Although the minor component composition of the soybean oils did not affect lipolysis during in vitro digestion, it influenced the extent of their oxidation and γ-tocopherol bioaccessibility. © 2019 Society of Chemical Industry.

Microvesicles from Human Adipose Tissue-Derived Mesenchymal Stem Cells as a New Protective Strategy in Osteoarthritic Chondrocytes.

BACKGROUND/AIMS: Chronic inflammation contributes to cartilage degeneration during the progression of osteoarthritis (OA). Adipose tissue-derived mesenchymal stem cells (AD-MSC) show great potential to treat inflammatory and degradative processes in OA and have demonstrated paracrine effects in chondrocytes. In the present work, we have isolated and characterized the extracellular vesicles from human AD-MSC to investigate their role in the chondroprotective actions of these cells. METHODS: AD-MSC were isolated by collagenase treatment from adipose tissue from healthy individuals subjected to abdominal lipectomy surgery. Microvesicles and exosomes were obtained from conditioned medium by filtration and differential centrifugation. Chondrocytes from OA patients were used in primary culture and stimulated with 10 ng/ml interleukin(IL)-1ß in the presence or absence of AD-MSC microvesicles, exosomes or conditioned medium. Protein expression was investigated by ELISA and immunofluorescence, transcription factor-DNA binding by ELISA, gene expression by real-time PCR, prostaglandin E2 (PGE2) by radioimmunoassay, and matrix metalloproteinase (MMP) activity and nitric oxide (NO) production by fluorometry. RESULTS: In OA chondrocytes stimulated with IL-1ß, microvesicles and exosomes reduced the production of inflammatory mediators tumor necrosis factor-α, IL-6, PGE2 and NO. The downregulation of cyclooxygenase-2 and microsomal prostaglandin E synthase-1 would lead to the decreased PGE2 production while the effect on NO could depend on the reduction of inducible nitric oxide synthase expression. Treatment of OA chondrocytes with extracellular vesicles also decreased the release of MMP activity and MMP-13 expression whereas the production of the anti-inflammatory cytokine IL-10 and the expression of collagen II were significantly enhanced. The reduction of inflammatory and catabolic mediators could be the consequence of a lower activation of nuclear factor-κB and activator protein-1. The upregulation of annexin A1 specially in MV may contribute to the anti-inflammatory and chondroprotective effects of AD-MSC. CONCLUSIONS: Our data support the interest of AD-MSC extracellular vesicles to develop new therapeutic approaches in joint conditions.

Improved pharmacokinetic profile of lipophilic anti-cancer drugs using ανß3-targeted polyurethane-polyurea nanoparticles.

Glutathione degradable polyurethane-polyurea nanoparticles (PUUa NP) with a disulfide-rich multiwalled structure and a cyclic RGD peptide as a targeting moiety were synthesized, incorporating a very lipophilic chemotherapeutic drug named Plitidepsin. In vitro studies indicated that encapsulated drug maintained and even improved its cytotoxic activity while in vivo toxicity studies revealed that the maximum tolerated dose (MTD) of Plitidepsin could be increased three-fold after encapsulation. We also found that pharmacokinetic parameters such as maximum concentration (Cmax), area under the curve (AUC) and plasma half-life were significantly improved for Plitidepsin loaded in PUUa NP. Moreover, biodistribution assays in mice showed that RGD-decorated PUUa NP accumulate less in spleen and liver than non-targeted conjugates, suggesting that RGD-decorated nanoparticles avoid sequestration by macrophages from the reticuloendothelial system. Overall, our results indicate that polyurethane-polyurea nanoparticles represent a very valuable nanoplatform for the delivery of lipophilic drugs by improving their toxicological, pharmacokinetic and whole-body biodistribution profiles.

Problems and solutions for patients with fibromyalgia: Building new helping relationships.

AIM: The aim of this study was to identify the main biological, psychological and sociological problems and potential solutions for patients diagnosed with fibromyalgia by use of Group Problem-Solving Therapy. BACKGROUND: Group Problem-Solving Therapy is a technique for identifying and solving problems, increasing assertiveness, self-esteem and eliminating negative thoughts. DESIGN: Qualitative phenomenological interpretive design: Group Problem-Solving Therapy sessions conducted with patients suffering fibromyalgia were studied; participants recruited via the Rheumatology Department at a general hospital and associations in Catalonia, Spain with sessions conducted in nearby university setting. METHODS: The study included 44 people diagnosed with fibromyalgia (43 female, 1 male) from 6 Group Problem-Solving Therapy sessions. Data collected from March-June 2013. A total of 24 sessions were audio recorded, all with prior informed consent. Data were transcribed and then analysed in accordance with established methods of inductive thematic analysis, via a process of reduction to manage and classify data. FINDINGS: Five themes were identified: (1) Current problems are often related to historical trauma; (2) There are no "one size fits all" solutions; (3) Fibromyalgia is life-changing; (4) Fibromyalgia is widely misunderstood; (5) Statistically Significant impacts on physical, psychological and social are described. CONCLUSION: The majority of patients' problems were associated with their previous history and the onset of fibromyalgia; which may be related to trauma in adolescence, early adulthood or later. The solutions provided during the groups appeared to be accepted by the participants. These findings can improve the self-management of fibromyalgia patients by helping to enhance adaptive behaviours and incorporating the female gender approach.

Xyloglucan, a Plant Polymer with Barrier Protective Properties over the Mucous Membranes: An Overview.

Disruption of the epithelial barrier function has been recently associated with a variety of diseases, mainly at intestinal level, but also affecting the respiratory epithelium and other mucosal barriers. Non-pharmacological approaches such as xyloglucan, with demonstrated protective barrier properties, are proposed as new alternatives for the management of a wide range of diseases, for which mucosal disruption and, particularly, tight junction alterations, is a common characteristic. Xyloglucan, a natural polysaccharide derived from tamarind seeds, possesses a "mucin-like" molecular structure that confers mucoadhesive properties, allowing xyloglucan formulations to act as a barrier capable of reducing bacterial adherence and invasion and to preserve tight junctions and paracellular flux, as observed in different in vitro and in vivo studies. In clinical trials, xyloglucan has been seen to reduce symptoms of gastroenteritis in adults and children, nasal disorders and dry eye syndrome. Similar mucosal protectors containing reticulated proteins have also been useful for the treatment of irritable bowel syndrome and urinary tract infections. The role of xyloglucan in other disorders with mucosal disruption, such as dermatological or other infectious diseases, deserves further research. In conclusion, xyloglucan, endowed with film-forming protective barrier properties, is a safe non-pharmacological alternative for the management of different diseases, such as gastrointestinal and nasal disorders.

The implementation of the Plan Esperanza and response to the imPACT Review.

Following the implementation of the National Cancer Prevention and Control Results-based Budget Programme (PpR Cancer-024) in 2011, the Peruvian Government approved the Plan Esperanza-a population-based national cancer control plan-in 2012. Legislation that ensured full government-supported funding for people who were otherwise unable to access or afford care and treatment accompanied the Plan. In 2013, the Ministry of Health requested an integrated mission of the Programme of Action for Cancer Therapy (imPACT) report to strengthen cancer control in Peru. The imPACT Review, which was executed in 2014, assessed Peru's achievements in cancer control, and areas for improvement, including cancer control planning, further development of population-based cancer registration, increased prevention, early diagnosis, treatment and palliative care, and the engagement and participation of civil society in the health-care system. This Series paper gives a brief history of the development of the Plan Esperanza, describes the innovative funding model that supports it, and summarises how funds are disseminated on the basis of disease, geography, and demographics. An overview of the imPACT Review, and the government's response in the context of the Plan Esperanza, is provided. The development and execution of the Plan Esperanza and the execution of and response to the imPACT Review demonstrates the Peruvian Government's commitment to fighting cancer across the country, including in remote and urban areas.

Influence of different salting processes on the evolution of the volatile metabolites of vacuum-packed fillets of farmed and wild sea bass (Dicentrarchus labrax) stored under refrigeration conditions: a study by SPME-GC/MS.

BACKGROUND: Fish shelf-life extension is a topic of great interest. In this study the behaviour of salted and unsalted farmed and wild European sea bass (Dicentrarchus labrax) fillets during storage was analysed through the evolution of their volatile metabolites. Farmed and wild sea bass fillets were brine-salted for 15 or 75 min, or dry-salted, vacuum-packed and stored at 4 °C for up to 1 month, and their headspaces were studied by Solid Phase Micro extraction-Gas Chromatography/Mass Spectrometry (SPME-GC/MS). RESULTS: At the same storage time, unsalted wild fillets contained, in general, a higher number and abundance of volatile compounds coming from microbiological or endogenous enzymatic activity than unsalted farmed ones. The more intense the salting, the lower the number and abundance of microbiological spoilage metabolites, especially in wild samples. The appearance of oxidation metabolites only in dry-salted wild samples evidences that this kind of salting provokes a certain oxidation in these samples. CONCLUSIONS: The better performance of farmed than wild fillets suggests that salted farmed fillets, vacuum-packed and stored under refrigeration conditions, could be a successful alternative to diversify the presence of sea bass in the market. © 2016 Society of Chemical Industry.

Immunomagnetic T Cell Depletion: an Analysis of Variables Affecting Final Cell Yield.

BACKGROUND: Only little detailed information has been published by a small number of centers on experiences with the technical aspects of "in vitro" large-scale graft manipulation technologies. METHODS: We report our experiences with the graft engineering procedures performed and the results obtained after T cell depletion. We have analyzed data from 212 procedures (108 CD34+ cell selection and 104 CD3+/CD19+ cell depletion). RESULTS: We conclude that the final cell products after selection or depletion were completely different with regard to CD34+ cell purity (95.8% vs. 1.52%). The CD34+ cell recovery after CD34+ cell selection is negatively affected when the initial leukocyte and/or CD34+ cell counts exceed the threshold defined by the manufacturer (68.9% vs. 45.2%, p < 0.01). However, the cell count threshold defined for the depletion technique could be exceeded without seriously affecting final results (86.1% vs. 86.4% for those with more or less than 40 x 109 leukocyte before the procedure; p = 0.7). Another important conclusion from this study is that in both CD34+ cell selection and CD3+/CD19+ cell depletion better results were reached after having gained experience by performing the procedures several times. This means that a learning process can be expected when using these in vitro graft manipulation procedures. CONCLUSIONS: It is extremely important to have experienced staff to perform these procedures. The expected results are different with each procedure so the decision on which of these T cell depletion approaches are used should be based on the characteristics of the final product wanted.

Farmed and wild sea bass (Dicentrarchus labrax) volatile metabolites: a comparative study by SPME-GC/MS.

BACKGROUND: Farmed and wild European sea bass (Dicentrarchus labrax) could be distinguished by its volatile metabolites, an issue not addressed until now. The aim of this work was to study these metabolites by solid-phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS). RESULTS: Both farmed and wild sea bass have a great number of volatile metabolites, most of them being in low concentrations. These include alcohols, aldehydes, ketones, alkylfurans, acids, aliphatic and aromatic hydrocarbons, terpenes, sulfur and nitrogen derivatives, 2,6-di-tert-butyl-4-methylphenol and one derived compound, as well as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, this latter compound presumably resulting from environmental contamination. Important differences have been detected between both types of sea bass, and also among individuals inside each group. Farmed specimens are richer in volatile metabolites than the wild counterparts; however, these latter, in general, contain a high number and abundance of metabolites resulting from microbial and enzymatic non-oxidative activity than the former. CONCLUSIONS: Clear differences in the volatile metabolites of wild and farmed sea bass have been found. A great deal of valuable information on sea bass volatile metabolites has been obtained, which can be useful in understanding certain aspects of the quality and safety of raw and processed sea bass.