Upadacitinib for moderate-to-severe atopic dermatitis: Stratified analysis from three randomized phase 3 trials by key baseline characteristics.

BACKGROUND: Atopic dermatitis (AD) is a heterogeneous inflammatory skin disease with different clinical phenotypes based on factors such as age, race, comorbidities, and clinical signs and symptoms. The effect of these factors on therapeutic responses in AD has only been scarcely studied and not for upadacitinib. Currently, there is no biomarker predicting response to upadacitinib. OBJECTIVES: Evaluate the efficacy of the oral Janus kinase inhibitor upadacitinib across patient subgroups (baseline demographics, disease characteristics and prior treatment) in patients with moderate-to-severe AD. METHODS: Data from phase 3 studies (Measure Up 1, Measure Up 2 and AD Up) were utilized for this post hoc analysis. Adults and adolescents with moderate-to-severe AD were randomized to receive once daily oral upadacitinib 15 mg, upadacitinib 30 mg or placebo; patients enrolled in the AD Up study received concomitant topical corticosteroids. Data from the Measure Up 1 and Measure Up 2 studies were integrated. RESULTS: A total of 2584 patients were randomized. A consistently greater proportion of patients achieved at least 75% improvement in the Eczema Area and Severity Index, a 0 or 1 on the validated Investigator Global Assessment for Atopic Dermatitis, and improvement in itch (including an achievement of a reduction of ≥4; and score of 0/1 in Worst Pruritus Numerical Rating Scale) with upadacitinib compared with placebo at Week 16, regardless of age, sex, race, body mass index, AD severity, body surface area involvement, history of atopic comorbidities or asthma, or previous exposure to systemic therapy or cyclosporin. CONCLUSIONS: Upadacitinib had consistently high skin clearance rates and itch efficacy across subgroups of patients with moderate-to-severe AD through Week 16. These results support upadacitinib as a suitable treatment option in a variety of patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifiers: NCT03569293 (Measure Up 1), NCT03607422 (Measure Up 2) and NCT03568318 (AD Up).

Children with psoriasis and COVID-19: factors associated with an unfavourable COVID-19 course, and the impact of infection on disease progression (Chi-PsoCov registry).

BACKGROUND: The COVID-19 pandemic has raised questions regarding the management of chronic skin diseases, especially in patients on systemic treatments. Data concerning the use of biologics in adults with psoriasis are reassuring, but data specific to children are missing. Moreover, COVID-19 could impact the course of psoriasis in children. OBJECTIVES: The aim of this study was therefore to assess the impact of COVID-19 on the psoriasis of children, and the severity of the infection in relation to systemic treatments. METHODS: We set up an international registry of paediatric psoriasis patients. Children were included if they were under 18 years of age, had a history of psoriasis, or developed it within 1 month of COVID-19 and had COVID-19 with or without symptoms. RESULTS: One hundred and twenty episodes of COVID-19 in 117 children (mean age: 12.4 years) were reported. The main clinical form of psoriasis was plaque type (69.4%). Most children were without systemic treatment (54.2%); 33 (28.3%) were on biologic therapies, and 24 (20%) on non-biologic systemic drugs. COVID-19 was confirmed in 106 children (88.3%) and 3 children had two COVID-19 infections each. COVID-19 was symptomatic for 75 children (62.5%) with a mean duration of 6.5 days, significantly longer for children on non-biologic systemic treatments (P = 0.02) and without systemic treatment (P = 0.006) when compared with children on biologics. The six children who required hospitalization were more frequently under non-biologic systemic treatment when compared with the other children (P = 0.01), and particularly under methotrexate (P = 0.03). After COVID-19, the psoriasis worsened in 17 cases (15.2%). Nine children (8%) developed a psoriasis in the month following COVID-19, mainly a guttate form (P = 0.01). DISCUSSION: Biologics appear to be safe with no increased risk of severe form of COVID-19 in children with psoriasis. COVID-19 was responsible for the development of psoriasis or the worsening of a known psoriasis for some children.

First International Public Health Film Competition 2016-reflections on the development and use of competition judging criteria.

Background: Film competitions can be a helpful method to understand issues of quality in health films. In this paper, we describe the development and use of explicit quality criteria to identify the 'best' films for the first ever international public health film competition. Methods: A film selection committee encompassing a range of stakeholders was compiled. The committee drew up 10 explicit quality criteria to judge films drawing upon other film festival's selection criteria. These criteria were then applied to a broad range of health-related films entered into a film competition to select the 'best' film to screen. Results: Eighty-four films from 20 different countries were submitted to the public health film competition. The originality of the subject covered by the film, the public health importance of the issue and story-telling approach in the film were found to be the most discriminatory criteria to select films. Conclusion: Selection of health films for festivals can be undertaken using explicit quality criteria. There are a number of advantages to such an approach; however, explicit selection involves a large commitment of resources from film festival organizers and there is further research required to test the validity of the quality criteria applied to health-related films.

Gemcitabine plus sirolimus for relapsed and progressing osteosarcoma patients after standard chemotherapy: a multicenter, single-arm phase II trial of Spanish Group for Research on Sarcoma (GEIS).

BACKGROUND: Patients with relapsed unresectable osteosarcoma represents an unmet need, so active and safe systemic treatments are required. Fas cell surface death receptor and mammalian target of rapamycin pathways are implicated in progressing osteosarcoma, and we had preclinical and clinical experience with a scheme that targets both pathways. Therefore, we designed a phase II trial with gemcitabine plus rapamycin, to determine the efficacy and safety, in this subset of patients. PATIENTS AND METHODS: A multicenter, single-arm phase II trial was sponsored by the Spanish Group for Research on Sarcoma. Osteosarcoma patients, relapsed or progressing after standard chemotherapy and unsuitable for metastasectomy received gemcitabine and rapamycin p.o. 5 mg/day except for the same day of gemcitabine administration, and the day before. The main end point was 4-month progression-free survival rate (PFSR), with the assumption that rates higher than 40% would be considered as an active regimen. Translational research aimed to correlate biomarkers with the clinical outcome. RESULTS: Thirty-five patients were enrolled and received at least one cycle. PFSR at 4 months was 44%, and after central radiologic assessment, 2 partial responses and 14 stabilizations (48.5%) were reported from 33 assessable patients. The most frequent grade 3-4 adverse events were: neutropenia (37%), thrombocytopenia (20%), anemia (23%), and fatigue (15%); however, only three patients had febrile neutropenia. Positive protein expression of RRM1 significantly correlated with worse PFS and overall survival, while positivity of P-ERK1/2 was correlated with significant better overall survival. CONCLUSION: Gemcitabine plus sirolimus exhibits satisfactory antitumor activity and safety in this osteosarcoma population, exceeding the prespecified 40% of 4-month PFSR. The significant correlation of biomarkers with clinical outcome encourages further prospective investigation.

Effect of bariatric surgery on microvascular dysfunction associated to metabolic syndrome: a 12-month prospective study.

OBJECTIVE: To prospectively evaluate the effect of weight loss after bariatric surgery on microvascular function in morbidly obese patients with and without metabolic syndrome (MetS). METHODS: A cohort of morbidly obese patients with and without MetS was studied before surgery and after 12 months of surgery. Healthy lean controls were also examined. Microvascular function was assessed by postocclusive reactive hyperemia (PORH) at forearm skin evaluated by laser Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was calculated from laser-Doppler skin blood flow and blood pressure. Regression analysis was performed to assess the contribution of different clinical, metabolic and biochemical parameters to microvascular function. RESULTS: Before surgery, 62 obese patients, 39 with MetS and 23 without MetS, and 30 lean control subjects were analyzed. The absolute area under the hyperemic curve (AUC(H)) CVC of PORH was significantly decreased in obese patients compared with lean control subjects. One year after surgery, AUC(H) CVC significantly increased in patients free of MetS, including patients that had MetS before surgery. In contrast, AUC(H) CVC did not significantly change in patients in whom MetS persisted after surgery. Stepwise multivariate regression analysis showed that only changes in HDL cholesterol (HDL-C) and oxidized LDL (oxLDL) independently predicted improvement of AUC(H) after surgery. These two variables together accounted for 40.9% of the variability of change in AUC(H) CVC after surgery. CONCLUSIONS: Bariatric surgery could significantly improve microvascular dysfunction in obese patients, but only in patients free of MetS after surgery. Improvement of microvascular dysfunction is strictly associated to postoperative increase in HDL-C levels and decrease in oxLDL levels.

Fabry disease in Argentina: an evaluation of patients enrolled in the Fabry Registry.

AIMS: Fabry disease (FD) is an X-linked inborn error of metabolism caused by alpha-galactosidase A deficiency. The Fabry Registry is an ongoing, global observational database that compiles clinical data from patients with FD. METHODS: Demographic and baseline clinical characteristics of Fabry Registry patients enrolled in Argentina were analysed and compared with patients enrolled in the rest of the world (ROW). Baseline clinical parameters included chronic kidney disease (CKD) stage, urine protein-to-creatinine ratio and left ventricular posterior wall thickness. Only data from untreated patients were included. RESULTS: As of 1 October 2010, 3752 patients were enrolled in the Registry, 70 patients from Argentina and 3682 from the ROW. Argentinean male subjects were younger than Fabry Registry male subjects enrolled in ROW: mean current age 32.5 years vs. 39.0 years for men (p = 0.0257 by t-test). The current age (mean ± standard deviation) of female subjects enrolled in Argentina was not significantly different from that of female subjects enrolled in the ROW: 40.1 ± 17.28 vs. 43.2 ±17.95 years respectively (p = 0.2967). Overall, a smaller percentage of patients from Argentina received ERT compared with patients in the ROW (54% vs. 58% respectively). When evaluated by gender, more men and fewer women in Argentina received ERT compared with ROW (85% vs. 79% for men and 27% vs. 38% for women). A larger proportion of patients in ROW had severe CKD (stage 4 or 5) compared with Argentina (9.8% vs. 0%), most likely because of the older age of the ROW population. CONCLUSIONS: The enrolment of Argentinean patients into the Fabry Registry has steadily increased, as has the inclusion of female and paediatric patients with FD. The medical community in Argentina should be aware of FD in these populations, as awareness will facilitate prompt diagnosis and initiation of treatment, thus leading to improved outcomes.

Cognitive Functioning in Adults with Phenylketonuria in a Cohort of Spanish Patients.

The early introduction of a low phenylalanine (Phe) diet has been demonstrated to be the most successful treatment in subjects with phenylketonuria (PKU), especially for preventing severe cognitive and neurological damages. However, it still concerns that even if treated in the first months of life with supplements and following a diet, they can show slight scores below people without PKU in neuropsychological assignments. We investigated 20 adults with classical PKU aged 19-48 years (mean age 29 years) and 20 heathy controls matched by age, gender, and years of education. Patients and controls were assessed with an extended neuropsychological battery, as well as psychological aspects and quality of life, also the last Phe level result was obtained. Results showed that the most affected cognitive domains are processing speed, executive functioning, memory, and also theory of mind, but very well-preserved verbal fluency, language, and visuospatial functioning. In quality of life, some significant results were seen specially in anxiety of Phe levels, anxiety of Phe levels during pregnancy, guilt if poor adherence to supplements, and if dietary protein restriction not followed. No significant results were obtained for the psychological variables. In conclusion, it has been shown that a combination of a low Phe diet, supplement intake, and keeping Phe levels in a low range seems appropriate to have the most normal and alike cognitive performance to persons without PKU.

Music therapy and Sanfilippo syndrome: an analysis of psychological and physiological variables of three case studies.

INTRODUCTION: Mucopolysaccharidosis type III (MPS III) or Sanfilippo syndrome is a neurodegenerative disease caused by the accumulation of mucopolysaccharides in the body. As the symptoms are wide ranging, it is a challenge to provide a diagnosis and psychological treatment for affected children. METHOD: The main objective of this study was to describe a form of music therapy treatment applied to three children diagnosed with MPS III. The psychological variables were evaluated by an ad hoc observation recording template, and the physiological variables were measured with a digital meter before and after each session. The perception of the parents was also considered through a semi-structured interview. RESULTS: An improvement in the psychological variables was shown in all cases. Changes in the physiological variables were also noted, although they varied according to each child. The parents report some benefit of music therapy and they share difficulty in assessing the extent of benefits of the music therapy. DISCUSSION: Findings indicate that music therapy can be a useful form of treatment with multiple benefits for children with conditions such as MPS III or similar conditions. However, further research is needed in this area and in the development of specific ways of evaluating music therapy.

Ketogenic diet and cognition in neurological diseases: a systematic review.

CONTEXT: In recent years, the ketogenic diet has gained special relevance as a possible therapeutic alternative to some neurological and chronic diseases. OBJECTIVE: The aim of this systematic review was to answer the following question: Does a ketogenic diet improve cognitive skills in patients with Alzheimer's disease, Parkinson's disease, refractory epilepsy, and type 1 glucose deficiency syndrome? To define the research question, the PICOS criteria were used, following the guidelines of the PRISMA method. DATA SOURCES: Medline/PubMed, Elsevier Science Direct, Dialnet, EBSCOhost, Mediagraphic, Sage Journals, ProQuest, and Wiley Online Library databases were used. DATA EXTRACTION: After applying inclusion and exclusion criteria in accordance with the PRISMA method, a total of 63 entries published between 2004 and 2019 were used. DATA ANALYSIS: The records extracted were analyzed from a qualitative approach, so no statistical analysis was carried out. CONCLUSION: Although scientific literature on the subject is scarce and there has tended to be a lack of scientific rigor, the studies reviewed confirmed the effectiveness of this diet in improving the cognitive symptomatology of the aforementioned diseases.

Effects of extruded linseed supplementation on n-3 fatty acids and conjugated linoleic acid in milk and cheese from ewes.

The objective of this study was to assess the effects of dietary supplementation of extruded linseed on animal performance and fatty acid (FA) profile of ewe milk for the production of n-3 FA- and conjugated linoleic acid-enriched cheeses. A Manchega ewe flock (300 animals) receiving a 60:40 forage:concentrate diet was divided into 3 groups supplemented with 0, 6, and 12 g of extruded linseed/100 g of dry matter for the control, low, and high extruded linseed diets, respectively. Bulk and individual milk samples from 5 dairy ewes per group were monitored at 7, 14, 28, 45, and 60 d following supplementation. Manchego cheeses were made with bulk milk from the 3 treatment groups. Milk yield increased in dairy ewes receiving extruded linseed. Milk protein, fat, and total solids contents were not affected by linseed supplementation. Milk contents of alpha-linolenic acid increased from 0.36 with the control diet to 1.91% total FA with the high extruded linseed diet. Similarly, cis-9 trans-11 C18:2 rose from 0.73 to 2.33% and its precursor in the mammary gland, trans-11 C18:1, increased from 1.55 to 5.76% of total FA. This pattern occurred with no significant modification of the levels of trans-10 C18:1 and trans-10 cis-12 C18:2 FA. Furthermore, the high extruded linseed diet reduced C12:0 (-30%), C14:0 (-15%) and C16:0 (-28%), thus significantly diminishing the atherogenicity index of milk. The response to linseed supplementation was persistently maintained during the entire study. Acceptability attributes of n-3-enriched versus control cheeses ripened for 3 mo were not affected. Therefore, extruded linseed supplementation seems a plausible strategy to improve animal performance and nutritional quality of dairy lipids in milk and cheese from ewes.

[Management models in clinical nutrition: weaknesses and strengths]. / Modelos de gestión en nutrición clínica: Puntos débiles y puntos fuertes.

At the 6th Abbott-SENPE Debate Forum a multidisciplinary and multiprofessional discussion was established in order to seek for the model or the models of clinical management most appropriate for Clinical Nutrition and Dietetics Units (CNAD) in Spain. The weaknesses and strengths as well as opportunities for the current systems were assessed concluding that a certain degree of disparity was observed not only due to regional differences but also to different hospital types. It was proposed, from SENPE, the creation of a working group helping to standardize the models and promote the culture of Integral Control and Change Management.

[National registry of home enteral nutrition in Spain 2007]. / Registro de Nutrición Enteral Domiciliaria en España en el año 2007.

OBJECTIVE: To communicate the results from the registry of Home-Based Enteral Nutrition of the NADYASENPE group in 2007. MATERIAL AND METHODS: We included every patient in the registry with home enteral nutrition any time from January 1st to December 31st of 2007. RESULTS: The number of patients with home enteral nutrition in 2007 was 5,107 (52% male) from 28 different hospitals. 95.4% of them were 15 yr or older, with a mean age of 67.96 +/- 18.12, and 4.2 +/- 3.38 among patients aged 14 yr or less. The most common underlying diseases were neurological (37.8%) and neoplastic diseases (29.3%). Enteral nutrition was administered p.o. in most patients (63.5%), followed by nasogastric tube (25.9%), while gastrostomy was only used in 9.2%. The mean time in enteral nutrition support was 9.4 months and the most common reasons for withdrawal were death (58.7%) and switching to oral intake (32%). Activity was limited in 31.4% of patients and 36.01% were house-bound. Most patients needed partial (26.51%) or total (37.68%) care assistance. Enteral formula was provided by hospitals to 69.14% of patients and by pharmacies to 30.17% of them, while disposable material was provided by hospitals to 81.63% and by Primary Care to the remaining patients. CONCLUSIONS: In 2007, there has been an increase of more than 30% of patients registered with home enteral nutrition comparing with 2006, without any big difference in other data, but a higher proportion of patients with enteral nutrition p.o.

A Spanish Society joint SECO and SEEDO approach to the Post-operative management of the patients undergoing surgery for obesity.

PURPOSE: Bariatric surgery is the method of choice for the management or treatment of obesity. Bariatric surgery brings about several physiological changes in the body and is associated with set of complications. The aim of this study is to provide guidelines on post bariatric surgery management based on consensus by the Spanish society for Obesity Surgery (Sociedad Española de Cirugía de la Obesidad) (SECO) and the Spanish Society for the Study of Obesity (Sociedad Española para el Estudio de la Obesidad) (SEEDO). METHOD: The boards proposed seven experts from each society. The experts provided the evidence and a grade of recommendation on the selected topics based on systematic reviews/meta-analysis. A list of clinical practical recommendations levels of evidence and grades of these recommendations was derived from the consensus statements from the members of these societies. RESULTS: Seventeen topics related to post-operative management were reviewed after bariatric surgery. The experts came with 47 recommendations and statements. The mean number of persons voting at each statement was 54 (range 36-76). CONCLUSION: In this consensus, we have designed a set of guidelines to be followed while managing patients after bariatric surgery. Expertise and knowledge of the clinicians are required to convey suitable considerations to the post-bariatric patients. There should also be extensive follow-up plans for the bariatric surgery patients.

Effect of a diet enriched in whole linseed and sunflower oil on goat milk fatty acid composition and conjugated linoleic acid isomer profile.

The aim of the present research was to study changes in milk composition and fatty acid profile, specifically conjugated linoleic acid (CLA) and its isomers, in goat milk as affected by dietary supplementation of sun-flower oil and whole linseed (0.81 and 1.84% of dry matter on basal diet, respectively) and to assess the persistency of the response. To achieve this objective, bulk milk from a herd and from 6 individual dairy goats fed a diet supplemented with sunflower oil and whole linseed was monitored for a period of 3 mo. Gas chromatography and silver ion HPLC were used to analyze total CLA content and the isomeric profile of these fatty acids, respectively. The contents of alpha-linolenic acid increased from 0.35% with the reference diet to 0.62% with the supplemented diet. Similarly, CLA milk content increased from 0.46 to 1.18%. The same pattern was also observed for trans-11 C18:1 (1.38 to 4.05%, respectively) in goat milk after 3 mo of lipid supplementation. In contrast, changes in other trans C18:1 isomers were less remarkable. There was a strong linear correlation between cis-9, trans-11 C18:2, the main CLA isomer, and trans-11 C18:1 under the conditions assayed and their concentration remained stable throughout the duration of the study. Levels of the minor CLA isomers were also enhanced as a consequence of lipid supplementation. The most remarkable increases were observed for 11-13 (trans-trans and trans-cis geometric isomers), whereas trans-7, cis-9 (the second most important CLA isomer from a quantitative point of view) and trans-10, cis-12 increased only slightly with lipid supplementation.

[V debate forum of the SENPE. Current issues on home-based and ambulatory artificial nutrition]. / V Foro de Debate SENPE: Problemática actual de la nutrición artificial domiciliaria y ambulatoria.

A multidisciplinary and multiprofessional debate is established trying to detect and find plausible solutions regarding Home-based and Ambulatory Enteral Nutrition (HBAEN) in Spain, due to the little attention paid by the Administration to the global problem of hyponutrition, the little interest showed by the collectivity of health care professionals, and the lack of a regulation differentiating the patient at his/her home and the patient at a nursing home. It was concluded that the current legislation on Home Based Enteral Nutrition (HBEN) has been variedly applied and does not contemplate the real clinical health care, with some pathologies subsidiary of this kind of therapy being excluded. Proposals to improve both financing and pathologies irrespective of the kind of nutritional therapy are made.

[Registry of home-based enteral nutrition in Spain for the year 2006 (NADYA-SENPE Group)]. / Registro de la Nutrición Enteral Domiciliaria en España en el año 2006 (Grupo NADYA-SENPE).

OBJECTIVE: To communicate the results obtained from the registry of Home-Based Enteral Nutrition (HBEN) of the NADYA-SENPE group for the year 2006. MATERIAL AND METHODS: Recompilation of the data from the HBEN registry of the NADYA-SENPE group from January 1st to December 31st of 2006. RESULTS: During the year 2006, 3,921 patients (51% men) from 27 hospital centers were registered. Ninety-seven percent were older than 14 years. The mean age for those < 14 years was 4.9 +/- 3.9 (m +/- SD) and in those > or = 14 years, it was 68.5 +/- 18.2 years. The most common underlying disease was neurological pathology (42%), followed by cancer (28%). Enteral nutrition was administered p.o. in 44% of the patients, through nasogastric tube in 40%, gastrostomy in 14%, and jejunostomy in 1%. The average time of nutritional support was 8.8 months. The most common reasons for ending the therapy were patient's death (54%) and switching to oral feeding (32%). Thirty-one percent of the patients presented a limited activity and 40% were confined to bed/coach. Most of the patients required partial (25%) or total (43%) care assistance. The nutritional formula was provided by the hospital in 62% of the cases and from the reference pharmacy in 27%. The fungible material was provided by the hospital in 80% of the cases and by primary care in the remaining patients. CONCLUSIONS: Although the number of registered patients is slightly higher than that from the last years, there are no important changes in the patients characteristics, or way of administration and duration of enteral nutrition.

Iso-Kikuchi Syndrome: Report of 3 Pediatric Cases. / Síndrome de Iso-Kikuchi: 3 casos en la edad pediátrica.

Iso-Kikuchi syndrome, or congenital onychodysplasia of the index finger, is an uncommon condition characterized by total anonychia or dysplasia of the nail of the index finger. It is occasionally accompanied by underlying bone abnormalities and is rarely associated with other conditions. Although various hypotheses have been put forward to explain the pathophysiology of the syndrome, its etiology remains unknown. We report the cases of 3 pediatric patients (2 boys and 1 girl) with nail changes and bone abnormalities consistent with Iso-Kikuchi syndrome. We highlight the importance of recognizing this entity early to avoid the need for additional tests and unnecessary treatment.

Integral nutritional approach to the care of cancer patients: results from a Delphi panel.

INTRODUCTION: Malnutrition is a common complication in cancer patients and can negatively affect the outcome of treatments. This study aimed to reach a consensus on nutritional needs and optimize nutritional care in the management of cancer patients at a national level. METHODS: A qualitative, multicenter, two-round Delphi study involving 52 specialists with experience in nutritional support in cancer patients was conducted. RESULTS: Regarding the presence of malnutrition, 57.7% of the participants stated that < 30% of the patients had malnutrition at the time of diagnosis, 40.4% considered that 31-50% had malnutrition during cancer treatment, and 26.9% that > 50% at the end of the treatment. Forty percent of participants believed that the main objective of nutritional treatment was to improve quality of life and 34.6% to improve tolerability and adherence to chemotherapy. The quality nutritional care provided at their centers was rated as medium-low by 67.3%. Enteral and parenteral nutrition was administered to less than 10% and less than 5% of patients in 40.4 and 76.9% of cases, respectively. In relation to nutritional screening at the time of diagnosis, 62.9% of participants considered than screening to assess the risk of malnutrition was performed in < 30% of patients. CONCLUSIONS: There is an important variability in the management of cancer patient nutrition, which is associated with the absence of a national consensus on nutritional support in this field. Given the incidence of nutritional disorders in cancer patients, a specialist in clinical nutrition (regardless of his/her specialty) should be integrated into the strategic cancer plan.

Differences in oxidation kinetics between conjugated and non-conjugated methyl linoleate.

The oxidation kinetics of conjugated methyl linoleate was compared with that of non-conjugated methyl linoleate under mild oxidation conditions (30 degrees C in the dark). Samples of methyl 9-cis,11-trans-linoleate, methyl 10-trans,12-cis linoleate and methyl 9-cis,12-cis linoleate were assayed separately and in mixtures. For comparative purposes, methyl alpha-linolenate and methyl oleate were also used. Two complementary analytical approaches were selected to monitor the progress of oxidation, (1) the traditional follow-up of residual substrate by gas liquid chromatography, and (2) an analytical procedure by high-performance size-exclusion chromatography (HPSEC) for direct measurement of the oxidation compounds formed. The HPSEC method enabled us to quantitate oxidized monomers, dimers and polymers concomitantly in a rapid and direct analysis. Results showed that conjugated methyl linoleate samples oxidized later than their non-conjugated counterparts, and showed a very different oxidation pattern. Thus, formation of oxidized monomers was negligible and the first and major compounds formed were polymerization products. Also, under the conditions used, non-conjugated and conjugated methyl linoleate samples in 1:1 mixtures led to decreased oxidation rate of non-conjugated methyl linoleate and increased oxidation rate of conjugated methyl linoleate. This study supports the view that oxidation kinetics of conjugated dienes differ substantially from that of methylene-interrupted dienes.