The role, the risk, and the reciprocity: creating positive early rural placements in medical education.

INTRODUCTION: The Northern Ontario School of Medicine University seeks to address rural physician shortages in Northern Ontario. One key strategy the school employs is the use of experiential learning placements embedded throughout its undergraduate curriculum. In second year, students embark on two 4-week placements in rural and remote communities. This study sought to explore the factors that contribute to a positive learning experience from the preceptor's perspective. METHODS: Semi-structured interviews were conducted with five community preceptors who have participated in these placements. Using the information from these interviews a survey was created and sent to another 15 preceptors. Data were analyzed using qualitative methods and frequencies. RESULTS: Three key themes were identified from both the interviews and survey data: the role of early rural and remote placements; the risks of these placements; and the need for a reciprocal relationship between institutions, preceptors, and students to create a positive learning environment. CONCLUSION: Preceptors value the opportunity to teach students, but the aims of these placements are not clear and preceptors and local hospitals need more workforce resources to make these experiences positive.

Quantification of methanol in the presence of ethanol by selected ion flow tube mass spectrometry.

The quantification of trace compounds in alcoholic beverages is a useful means to both investigate the chemical basis of beverage flavor and to facilitate quality control during the production process. One compound of interest is methanol which, due to it being toxic, must not exceed regulatory limits. The analysis of headspace gases is a desirable means to do this since it does not require direct sampling of the liquid material. One established means to conduct headspace analysis is selected ion flow tube mass spectrometry (SIFT-MS). The high concentration of ethanol present in the headspace of alcoholic drinks complicates the analysis, however, via reacting with the precursor ions central to this technique. We therefore investigated whether methanol could be quantified in the presence of a large excess of ethanol using SIFT-MS. We found that methanol reacted with ionized ethanol to generate product ions that could be used to quantify methanol concentrations and used this technique to quantify methanol in beverages containing different quantities of ethanol. We conclude that SIFT-MS can be used to quantify trace compounds in alcoholic beverages by determining the relevant reaction chemistry.

How early clinical experiences in rural communities influence student learning about rural generalism considered through the lens of educational theory.

Introduction: Rural communities have poorer health compared to urban populations due partly to having lesser healthcare access. Rural placements during medical education can equip students with the knowledge and skills to work in rural communities, and, it is hoped, increase the supply of rural physicians. It is unclear how students gain knowledge of rural generalism during placements, and how this can be understood in terms of place-based and/or sociocultural educational theories. To gain insight into these questions we considered the experiences of pre-clerkship medical students who completed two mandatory four-week rural placements during their second year of medical school. Methods: Data was collected using semi-structured interviews or focus groups, followed by thematic analysis of the interview transcripts. Results: Rural placements allowed students to learn about rural generalism such as breadth of practice, and boundary issues. This occurred mainly by students interacting with rural physician faculty, with the effectiveness of precepting being key to students acquiring knowledge and skills and reporting a positive regard for the placement experience. Discussion: Our data show the central role of generalist physician preceptors in how and what students learn while participating in rural placements. Sociocultural learning theory best explains student learning, while place-based education theory helps inform the curriculum. Effective training and preparation of preceptors is likely key to positive student placement experiences.

Introduction: Les communautés rurales sont en moins bonne santé que les populations urbaines, en partie parce qu'elles ont moins accès aux soins de santé. Les stages de médecine en milieu rural peuvent permettre aux étudiants d'acquérir les connaissances et les compétences nécessaires pour travailler dans les communautés rurales et, on l'espère, augmenter le nombre de médecins y travaillent. On ne sait pas clairement comment les étudiants acquièrent des connaissances sur le généralisme rural au cours de leurs stages, et comment cela peut être compris en termes de théories éducatives socioculturelles et/ou basées sur le lieu de travail. Pour répondre à ces questions, nous avons étudié les expériences d'étudiants en médecine au pré-clinique qui ont effectué deux stages obligatoires de quatre semaines en milieu rural au cours de leur deuxième année d'études de médecine. Méthodes: Les données ont été recueillies au moyen d'entrevues semi-structurées ou de groupes de discussion, suivis d'une analyse thématique des transcriptions des entrevues. Résultats: Les stages en milieu rural ont permis aux étudiants de se familiariser avec le généralisme rural, notamment l'étendue de la pratique et les questions de limites. L'efficacité du préceptorat est essentielle pour que les étudiants acquièrent des connaissances et des compétences et qu'ils aient une expérience de stage positive. Discussion: Nos données témoignent du rôle central que jouent les médecins généralistes précepteurs quant au contenu et modes d'apprentissage des étudiants lorsqu'ils participent à des stages en milieu rural. La théorie de l'apprentissage socioculturel est celle qui explique le mieux l'apprentissage des étudiants, tandis que la théorie de la formation fondée sur le lieu contribue à orienter le programme d'études. Une formation et préparation efficace des précepteurs est probablement la clé d'une expérience de stage positive pour les étudiants.

A geographic-location-based medical school admissions process does not influence pre-clerkship and licensing examination academic performance.

Background: Students are selected for admission to the Northern Ontario School of Medicine University (NOSM U) MD degree program using criteria aiming to maximize access of persons thought most likely to practice in the region, including use of a geographic context score (GCS) which ranks those with lived experience in northern Ontario and/or rurality most highly. This study investigates the effect of this admissions process upon medical school academic performance. Methods: We used a retrospective cohort design combined with multiple linear regression analysis to investigate the relationship between admission scores and performance on pre-clerkship courses, and the Medical Council of Canada Qualifying Exam Part 1 (MCCQE1).The GCS did not significantly explain performance variance on any pre-clerkship course, nor on the MCCQE1, while the undergraduate Grade Point Average correlated with most assessment scores. The number of prior undergraduate biomedical courses predicted science and clinical skills performance, particularly in Year 1, but not with MCCQE1 scores. Performance on Year 2 courses, particularly foundational sciences and clinical skills, significantly predicted MCCQE1 scores. Results: Our data suggest that admission geographic context scoring is unrelated to future academic performance. Further, students with fewer prior undergraduate biomedical courses may benefit from increased support and/or a modified program during the early years.

Contexte: La sélection étudiants à l'École de médecine du Nord de l'Ontario est fondée sur des critères visant à faciliter l'admission de candidats qu'on estime susceptibles de pratiquer dans la région. Un de ces critères est le score de contexte géographique (SCG) qui classe au premier rang les personnes ayant déjà vécu dans le Nord de l'Ontario ou en milieu rural. Cette étude examine l'effet de ce processus d'admission sur les résultats académiques des étudiants en médecine. Méthodes: Nous avons utilisé un modèle de cohorte rétrospective et une analyse par régression linéaire multiple pour étudier la relation entre les scores d'admission et les résultats obtenus aux cours avant l'externat et à l'examen d'aptitude du Conseil médical du Canada (EACMC), partie 1.Le SCG n'explique pas de manière significative la variance des résultats dans les cours pré-cliniques, ni à l'EACMC1, tandis que la moyenne pondérée cumulative au premier cycle est en corrélation avec la plupart des scores d'évaluation. Le nombre de cours en sciences biomédicales suivis dans un programme de premier cycle ont permis de prédire les résultats en sciences et en compétences cliniques, en particulier en première année, mais pas les résultats à l'EACMC1. Les résultats aux cours de deuxième année, en particulier de sciences fondamentales et de compétences cliniques, ont permis de prédire de manière significative les résultats à l'EACMC1. Résultats: Nos données portent à croire que le score de contexte géographique au moment de l'admission est sans lien avec les résultats académiques subséquents. En outre, les étudiants ayant suivi moins de cours en sciences biomédicales au premier cycle pourraient bénéficier d'un soutien plus important ou d'un programme adapté au cours des premières années.

Quantification of character-impacting compounds in Ocimum basilicum and 'Pesto alla Genovese' with selected ion flow tube mass spectrometry.

Basil (Ocimum basilicum) is an important flavourant plant which constitutes the major ingredient of the pasta sauce 'Pesto alla Genovese'. The characteristic smell of basil stems mainly from a handful of terpenoids (methyl cinnamate, eucalyptol, linalool and estragole), the concentration of which varies according to basil cultivars. The simple and rapid analysis of the terpenoid constituents of basil would be useful as a means to optimise harvesting times and to act as a quality control process for basil-containing foodstuffs. Classical analytical techniques such as gas chromatography/mass spectrometry (GC/MS) are, however, slow, technically demanding and therefore less suitable for routine analysis. A new chemical ionisation technique which allows real-time quantification of traces gases, Selected Ion Flow Tube Mass Spectrometry (SIFT-MS), was therefore utilised to determine its usefulness for the assay of terpenoid concentrations in basil and pesto sauce headspace. Trace gas analysis was performed using the NO(+) precursor ion which minimised interference from other compounds. Character-impacting compound concentration was measured in basil headspace with good reproducibility and statistically significant differences were observed between cultivars. Quantification of linalool in pesto sauce headspace proved more difficult due to the presence of interfering compounds. This was resolved by careful selection of reaction product ions which allowed us to detect differences between various commercial brands of pesto. We conclude that SIFT-MS may be a valid tool for the fast and reproducible analysis of flavourant terpenoids in basil and basil-derived foodstuffs.

The reactions of a series of terpenoids with H(3) O(+) , NO(+) and O 2+ studied using selected ion flow tube mass spectrometry.

The reactions of H(3) O(+) , NO(+) and O 2+ with twelve terpenoids and one terpene, all of which occur naturally in plants and which possess important smell and flavourant properties, were characterized using Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). The H(3) O(+) reactions resulted primarily in the formation of the proton transfer product and occasionally in a water elimination product. The NO(+) reactions instead generated the charge transfer product or NO(+) adducts, and occasionally alkyl fragments, or resulted in hydride abstraction. Reaction with O 2+ caused a higher fragmentation of the terpenoids with the molecular ion being the minor product of most reactions. Identification and quantification of each compound in complex mixtures are probably possible in most cases using the H(3) O(+) and/or NO(+) precursors while O 2+ may be useful for isomer discrimination. Our data suggests that SIFT-MS may be a useful tool for the rapid analysis of these compounds in plants and derived foodstuffs.

The reactions of H(3)O(+), NO(+) and O(2) (+) with several flavourant esters studied using selected ion flow tube mass spectrometry.

The reactions of H(3)O(+), NO(+), and O(2) (+) with nineteen ester compounds occurring naturally in plants, and having important flavourant properties, were examined using selected ion flow tube mass spectrometry (SIFT-MS). The H(3)O(+) reactions primarily generate [R(1)COOR(2).H](+), and may also produce [R(2)](+) fragment ions and/or fragmentation within the ester linkage. Collisional association/adduct ions, [R(1)COOR(2).NO](+), are the main products formed in the NO(+) reactions, although the carboxyl fragment ion is also detected frequently. The identification of the parent compound may be made more easily in the H(3)O(+) and NO(+) reactions. The inclusion of O(2) (+) reactions in the analysis provides additional information, which may be applied when the identity of a parent compound cannot be determined solely from the H(3)O(+) and NO(+) analysis. Consideration of the product ions generated with the three precursors suggests that SIFT-MS can differentiate between many of the esters investigated, including isomers, although the product ions generated in the reactions with some esters are too similar to allow independent quantification. Our data therefore suggest that SIFT-MS may be a useful tool to rapidly analyse and quantify flavourant esters in complex gas mixtures.

The use of selected ion flow tube mass spectrometry to detect and quantify polyamines in headspace gas and oral air.

Polyamines are a class of aliphatic compounds which include putrescine, cadaverine, spermine and spermidine. They are involved in a variety of cellular processes and have been implicated in a number of different pathophysiological mechanisms. Polyamines are volatile compounds having a distinctive odour normally perceived as being unpleasant. The measurement of their abundance has, however, been restricted to compounds present in the aqueous phase. Using selected ion flow tube mass spectrometry (SIFT-MS) we have shown that the polyamines react with the ions H3O+, NO+ and O2+ to form distinctive product ions allowing their levels to be quantified in the vapour phase. The low volatility of spermine did not allow extensive analysis of this compound by SIFT-MS while the adherent properties of cadaverine and putrescine required the use of PTFE transfer lines and couplers. Our data suggested the presence of cadaverine and putrescine in both oral air and the headspace of putrefying bovine muscle, while product ions corresponding to putrescine and spermidine were found in the headspace of human semen. SIFT-MS therefore appears to be a practical means of measuring vapour-phase polyamine levels, having applications in biology, medicine and dentistry, and food science.

A Qualitative Investigation of the Experiences of Students and Preceptors Taking Part in Remote and Rural Community Experiential Placements During Early Medical Training.

BACKGROUND: Medical education can help alleviate the chronic undersupply of physicians to rural communities. Providing students with early rural clinical experiences may allow the gaining of necessary knowledge and skills to practice and live rurally, as well as the desire to do so. PURPOSE: This study aims to provide a detailed understanding of Remote and Rural Community Placements (RRCPs) which occur in the second year of a Doctor of Medicine programme. METHODOLOGY/APPROACH: Using a thematic analysis approach, we examined the experiences of students and preceptors in the RRCP. Data were collected using semi-structured interviews and focus groups. FINDINGS/CONCLUSIONS: Students valued RRCPs as a formative clinical experience and preceptors gained professionally from participating. The RRCPs enhanced students regard for, and knowledge of, rural medicine. Yet, contrary to the stated aims of the placement, students spent very little time in activities outside of the clinic, neither learning about the community nor about the life of a physician as a community member. IMPLICATIONS: Medical educators should recognise that students and preceptors will inevitably place different value on the different sociocultural and perceptual aspects of placements, namely clinical and non-clinical. As such, the curriculum should draw clearly articulated links between each.

Increased levels of ethane, a non-invasive, quantitative, direct marker of n-3 lipid peroxidation, in the breath of patients with schizophrenia.

This study directly assessed whether there was a change in the level of exhaled ethane, which provides a non-invasive, quantitative, direct measure of n-3 lipid peroxidation, in the breath of patients with schizophrenia. Samples of alveolar air were obtained from 20 subjects with schizophrenia and 23 age- and sex-matched healthy control subjects. The air samples were analyzed for ethane using mass spectrometry. The mean level of ethane in the schizophrenia sample [5.15 (S.E. 0.56) ppb] was significantly higher than that of the healthy controls [2.63 (S.E. 0.31) ppb; p<0.0005]. A further sub-analysis showed that nicotine dependence was unlikely to be the cause of this difference. These results suggest that the measurement of exhaled ethane levels may offer a non-invasive direct biomarker of increased n-3 lipid peroxidation in schizophrenia.

Evidence from in vivo 31-phosphorus magnetic resonance spectroscopy phosphodiesters that exhaled ethane is a biomarker of cerebral n-3 polyunsaturated fatty acid peroxidation in humans.

BACKGROUND: This study tested the hypothesis that exhaled ethane is a biomarker of cerebral n-3 polyunsaturated fatty acid peroxidation in humans. Ethane is released specifically following peroxidation of n-3 polyunsaturated fatty acids. We reasoned that the cerebral source of ethane would be the docosahexaenoic acid component of membrane phospholipids. Breakdown of the latter also releases phosphorylated polar head groups, giving rise to glycerophosphorylcholine and glycerophosphorylethanolamine, which can be measured from the 31-phosphorus neurospectroscopy phosphodiester peak. Schizophrenia patients were chosen because of evidence of increased free radical-mediated damage and cerebral lipid peroxidation in this disorder. METHODS: Samples of alveolar air were obtained from eight patients and ethane was analyzed and quantified by gas chromatography and mass spectrometry (m/z = 30). Cerebral 31-phosphorus spectra were obtained from the same patients at a magnetic field strength of 1.5 T using an image-selected in vivo spectroscopy sequence (TR = 10 s; 64 signal averages localized on a 70 x 70 x 70 mm3 voxel). The quantification of the 31-phosphorus signals using prior knowledge was carried out in the temporal domain after truncating the first 1.92 ms of the signal to remove the broad component present in the 31-phosphorus spectra. RESULTS: The ethane and phosphodiester levels, expressed as a percentage of the total 31-phosphorus signal, were positively and significantly correlated (rs = 0.714, p < 0.05). CONCLUSION: Our results support the hypothesis that the measurement of exhaled ethane levels indexes cerebral n-3 lipid peroxidation. From a practical viewpoint, if human cerebral n-3 polyunsaturated fatty acid catabolism can be measured by ethane in expired breath, this would be more convenient than determining the area of the 31-phosphorus neurospectroscopy phosphodiester peak.

A comparison of oxidative stress in smokers and non-smokers: an in vivo human quantitative study of n-3 lipid peroxidation.

BACKGROUND: Cigarette smoking is believed to cause oxidative stress by several mechanisms, including direct damage by radical species and the inflammatory response induced by smoking, and would therefore be expected to cause increased lipid peroxidation. The aim was to carry out the first study of the relationship of smoking in humans to the level of n-3 lipid peroxidation indexed by the level of ethane in exhaled breath. METHODS: Samples of alveolar air were obtained from 11 smokers and 18 non-smokers. The air samples were analyzed for ethane using mass spectrometry. RESULTS: The two groups of subjects were matched with respect to age and gender. The mean cumulative smoking status of the smokers was 11.8 (standard error 2.5) pack-years. The mean level of ethane in the alveolar breath of the group of smokers (2.53 (0.55) ppb) was not significantly different from that of the group of non-smokers (2.59 (0.29) ppb; p = 0.92). With all 29 subjects included, the Spearman rank correlation coefficient between ethane levels and cumulative smoking status was -0.11 (p = 0.58), while an analysis including only the smokers yielded a corresponding correlation coefficient of 0.11 (p = 0.75). CONCLUSION: Our results show no evidence that cigarette smoking is related to increased n-3 lipid peroxidation as measured by expired ethane.

Methylnicotinate stimulated prostaglandin synthesis in patients with schizophrenia: A preliminary investigation.

Schizophrenia is a serious mental illness of unclear aetiology. The reduced ability of methylnicotinate to induce a topical vasodilatory response in patients with the disorder is well established. Methylnicotinate causes vasodilation via stimulating the release of prostaglandins (including prostaglandin D2) in the skin which in turn leads to relaxation of vascular smooth muscle. To determine whether the abnormality is likely to be due to decreased prostaglandin production, or a decreased effect of prostaglandins upon the vessels, topical methylnicotinate was applied to the forearms of patients with schizophrenia or healthy controls, followed by rating of the resulting erythema. The concentration of prostaglandin D2 and its metabolite 11ß-prostaglandin F2α in the blood draining the arm was also measured. Although erythema was reduced in the patient group, this was not correlated with plasma prostaglandin concentrations. This data suggests the abnormality underlying the reduced potency of methylnicotinate to produce vasodilation in the disorder occurs downstream of prostaglandin synthesis possibly within the vasculature itself.

Antioxidant modulation of oxidant-stimulated uptake and release of arachidonic acid in eicosapentaenoic acid-supplemented human lymphoma U937 cells.

Omega-3 polyunsaturated fatty acids (PUFA) are increasingly finding use as treatments for a variety of medical conditions. PUFA supplementation can, however, result in increased oxidative stress causing elevated turnover rate of membrane phospholipids, impairment of membrane integrity and increased formation of inflammatory mediators. The aim of this study was to determine which antioxidant compounds were most effective in ameliorating the stimulation of phospholipid turnover by oxidative stress. U937 cells were supplemented with eicosapentaenoic acid and either ascorbic acid, alpha-tocopherol, beta-carotene or astaxanthin prior to being challenged with oxidant. Although all antioxidants were found to be effective in decreasing oxidant-stimulated peroxide formation, only alpha-tocopherol significantly decreased oxidant-stimulated release of 3H-labeled arachidonic acid (AA), while ascorbic acid markedly increased release. All antioxidants except alpha-tocopherol decreased oxidant-stimulated 3H-AA uptake. Our data suggest that antioxidants are not equally effective in combating the effects of oxidative stress upon membrane phospholipid turnover, and that optimal protection will require mixtures of antioxidants.

Omega-3 fatty acids as treatments for mental illness: which disorder and which fatty acid?

BACKGROUND: A growing number of observational and epidemiological studies have suggested that mental illness, in particular mood disorders, is associated with reduced dietary intake and/or cellular abundance of omega-3 polyunsaturated fatty acids (PUFA). This has prompted researchers to test the efficacy of omega-3 PUFA in a range of different psychiatric disorders. We have critically reviewed the double blind placebo controlled clinical trials published prior to April 2007 to determine whether omega-3 PUFA are likely to be efficacious in these disorders. RESULTS: Most trials involved a small number of participants but were largely well designed. Omega-3 PUFA were well tolerated by both children and adults with mild gastrointestinal effects being the only consistently reported adverse event. For schizophrenia and borderline personality disorder we found little evidence of a robust clinically relevant effect. In the case of attention deficit hyperactivity disorder and related disorders, most trials showed at most small benefits over placebo. A limited meta-analysis of these trials suggested that benefits of omega-3 PUFA supplementation may be greater in a classroom setting than at home. Some evidence indicates that omega-3 PUFA may reduce symptoms of anxiety although the data is preliminary and inconclusive. The most convincing evidence for beneficial effects of omega-3 PUFA is to be found in mood disorders. A meta-analysis of trials involving patients with major depressive disorder and bipolar disorder provided evidence that omega-3 PUFA supplementation reduces symptoms of depression. Furthermore, meta-regression analysis suggests that supplementation with eicosapentaenoic acid may be more beneficial in mood disorders than with docosahexaenoic acid, although several confounding factors prevented a definitive conclusion being made regarding which species of omega-3 PUFA is most beneficial. The mechanisms underlying the apparent efficacy of omega-3 PUFA in mood disorders compared to schizophrenia are discussed as is a rational for the possibly greater efficacy of EPA compared to DHA. CONCLUSION: While it is not currently possible to recommend omega-3 PUFA as either a mono- or adjunctive-therapy in any mental illness, the available evidence is strong enough to justify continued study, especially with regard to attentional, anxiety and mood disorders.

Omega-3 fatty acid deficiency in major depressive disorder is caused by the interaction between diet and a genetically determined abnormality in phospholipid metabolism.

Omega-3 fatty acids are a type of polyunsaturated fatty acid (PUFA). A growing body of evidence suggests that this form PUFA is a useful and well tolerated treatment for major depressive disorder, a common and serious mental illness. The efficacy of omega-3 PUFA is routinely explained as being due to a deficiency caused by inadequate dietary intake of this class of fatty acid. The hypothesis considered states that low omega-3 PUFA abundance in patients with major depressive and related disorders is due to an underlying genetically determined abnormality. The hypothesis can explain why although a specific and consistent deficit in omega-3, but not omega-6, PUFA occurs in major depressive and related disorders, the literature does not consistently support the notion that this is due to deficient dietary intake. Specifically it is hypothesized that having genetically determined low activity of fatty acid CoA ligase 4 and/or Type IV phospholipase A(2) combined with the low dietary availability of omega-3 PUFA results in reduced cellular uptake of omega-3 PUFA and constitutes a risk factor for depression. The hypothesis also has important consequences for the pharmacological treatment of depression in that it predicts that administering agents which enhance phospholipid synthesis, particularly those containing ethanolamine such as CDP-ethanolamine, should be effective antidepressants especially when co-administered with omega-3 PUFA.

Volatile compounds in blood headspace and nasal breath.

Breath analysis is a form of metabolomics that utilises the identification and quantification of volatile chemicals to provide information about physiological or pathological processes occurring within the body. An inherent assumption of such analyses is that the concentration of the exhaled gases correlates with the concentration of the same gas in the tissue of interest. In this study we have investigated this assumption by quantifying some volatile compounds in peripheral venous blood headspace, and in nasal breath collected in Tedlar bags obtained at the same time from 30 healthy volunteers, prior to analysis by selected ion flow tube mass spectrometry. Some endogenous compounds were significantly correlated between blood headspace and nasal breath, such as isoprene (r p = 0.63) and acetone (r p = 0.68), however many, such as propanol (r p = -0.26) and methanol (r p = 0.23), were not. Furthermore, the relative concentrations of volatiles in blood and breath varied markedly between compounds, with some, such as isoprene and acetone, having similar concentrations in each, while others, such as acetic acid, ammonia and methanol, being significantly more abundant in breath, and others, such as methanal, being detectable only in breath. We also observed that breath propanol and acetic acid concentrations were higher in male compared to female participants, and that the blood headspace methanol concentration was negatively correlated to body mass index. No relationship between volatile concentrations and age was observed. Our data suggest that breath concentrations of volatiles do not necessarily give information about the same compound in the blood stream. This is likely due to the upper airway contributing compounds over and above that originating in the circulation. An investigation of the relationship between breath volatile concentrations and that in the tissue(s) of interest should therefore become a routine part of the development process of breath-based biomarkers.

Dietary omega-3 polyunsaturated fatty acid supplementation in an animal model of anxiety.

A large body of evidence suggests that dietary supplementation with omega-3 fatty acids may ameliorate depressed mood. The magnitude of the effect varies between studies, however, ranging from none at all to being of clinical significance. Given that substantial comorbidity occurs between mood and anxiety disorders, suggesting that they have one or more pathophysiological mechanisms in common, we hypothesized that omega-3 fatty acids may be acting primarily to reduce anxiety rather than depression per se, a possibility which could underlie their variable effects on mood. To test this hypothesis rats were fed for 8 weeks with diets containing one of three types of omega-3 fatty acids, alpha-linolenic acid, eicosapentaenoic acid and docosahexaenoic acid, as well as a low omega-3 fatty acid control diet. Although brain omega-3 fatty acid concentrations were altered by dietary supplementation with eicospentaenoic acid and docosahexaenoic acid, no significant change in anxiety related behaviors were observed compared to the control group as assessed by the elevated-plus maze test. Our data therefore do not support an anxiolytic effect of omega-3 fatty acids and suggest that any effect of these lipids on mood likely occurs by a mechanism unrelated to reducing anxiety.

Brain and Liver Headspace Aldehyde Concentration Following Dietary Supplementation with n-3 Polyunsaturated Fatty Acids.

Reactive oxygen species react with unsaturated fatty acids to form a variety of metabolites including aldehydes. Many aldehydes are volatile enough to be detected in headspace gases of blood or cultured cells and in exhaled breath, in particular propanal and hexanal which are derived from omega-3 and omega-6 polyunsaturated fatty acids, respectively. Aldehydes are therefore potential non-invasive biomarkers of oxidative stress and of various diseases in which oxidative stress is thought to play a role including cancer, cardiovascular disease and diabetes. It is unclear, however, how changes in the abundance of the fatty acid precursors, for example by altered dietary intake, affect aldehyde concentrations. We therefore fed male Wistar rats diets supplemented with either palm oil or a combination of palm oil plus an n-3 fatty acid (alpha-linolenic, eicosapentaenoic, or docosahexaenoic acids) for 4 weeks. Fatty acid analysis revealed large changes in the abundance of both n-3 and n-6 fatty acids in the liver with smaller changes observed in the brain. Despite the altered fatty acid abundance, headspace concentrations of C1-C8 aldehydes, and tissue concentrations of thiobarbituric acid reactive substances, did not differ between the 4 dietary groups. Our data suggest that tissue aldehyde concentrations are independent of fatty acid abundance, and further support their use as volatile biomarkers of oxidative stress.