58 research outputs found

    The Role of Adipokines in Understanding the Associations between Obesity and Depression

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    Objective. Two major causes of disability, major depression and obesity, share overlapping psychosocial and pathophysiological etiologies. Studies are now focused on biological mechanisms linking the two illnesses, and there is interest in the role that adipokines may have in mediating the association between obesity and depression. We reviewed the literature to look at what is currently known about this association, focusing on the adipokines leptin, adiponectin, and resistin. Methods. A MEDLINE search, citing articles from 1966 onward, supplemented by a review of bibliographies, was conducted to identify relevant studies. Results. This paper identified plausible pathways underlying a link between adipokines and depression. Only a few studies have yet been conducted specifically examining these biomarkers in patients with depression, but the results are intriguing. Conclusion. This paper is one of the first to examine the association between adipokines and depression. It provides an overview of the physiological role of adipokines and summarizes the data suggesting that they may be dysregulated in major depression. This area of research may become increasingly important as new treatment strategies are developed

    Multisite Comparison of MRI Defacing Software Across Multiple Cohorts

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    With improvements to both scan quality and facial recognition software, there is an increased risk of participants being identified by a 3D render of their structural neuroimaging scans, even when all other personal information has been removed. To prevent this, facial features should be removed before data are shared or openly released, but while there are several publicly available software algorithms to do this, there has been no comprehensive review of their accuracy within the general population. To address this, we tested multiple algorithms on 300 scans from three neuroscience research projects, funded in part by the Ontario Brain Institute, to cover a wide range of ages (3–85 years) and multiple patient cohorts. While skull stripping is more thorough at removing identifiable features, we focused mainly on defacing software, as skull stripping also removes potentially useful information, which may be required for future analyses. We tested six publicly available algorithms (afni_refacer, deepdefacer, mri_deface, mridefacer, pydeface, quickshear), with one skull stripper (FreeSurfer) included for comparison. Accuracy was measured through a pass/fail system with two criteria; one, that all facial features had been removed and two, that no brain tissue was removed in the process. A subset of defaced scans were also run through several preprocessing pipelines to ensure that none of the algorithms would alter the resulting outputs. We found that the success rates varied strongly between defacers, with afni_refacer (89%) and pydeface (83%) having the highest rates, overall. In both cases, the primary source of failure came from a single dataset that the defacer appeared to struggle with - the youngest cohort (3–20 years) for afni_refacer and the oldest (44–85 years) for pydeface, demonstrating that defacer performance not only depends on the data provided, but that this effect varies between algorithms. While there were some very minor differences between the preprocessing results for defaced and original scans, none of these were significant and were within the range of variation between using different NIfTI converters, or using raw DICOM files

    nnResting state fMRI scanner instabilities revealed by longitud inal phantom scans in a multi-center study

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    Quality assurance (QA) is crucial in longitudinal and/or multi-site studies, which involve the collection of data from a group of subjects over time and/or at different locations. It is important to regularly monitor the performance of the scanners over time and at different locations to detect and control for intrinsic differences (e.g., due to manufacturers) and changes in scanner performance (e.g., due to gradual component aging, software and/or hardware upgrades, etc.). As part of the Ontario Neurodegenerative Disease Research Initiative (ONDRI) and the Canadian Biomarker Integration Network in Depression (CAN-BIND), QA phantom scans were conducted approximately monthly for three to four years at 13 sites across Canada with 3T research MRI scanners. QA parameters were calculated for each scan using the functional Biomarker Imaging Research Network\u27s (fBIRN) QA phantom and pipeline to capture between- and within-scanner variability. We also describe a QA protocol to measure the full-width-at-half-maximum (FWHM) of slice-wise point spread functions (PSF), used in conjunction with the fBIRN QA parameters. Variations in image resolution measured by the FWHM are a primary source of variance over time for many sites, as well as between sites and between manufacturers. We also identify an unexpected range of instabilities affecting individual slices in a number of scanners, which may amount to a substantial contribution of unexplained signal variance to their data. Finally, we identify a preliminary preprocessing approach to reduce this variance and/or alleviate the slice anomalies, and in a small human data set show that this change in preprocessing can have a significant impact on seed-based connectivity measurements for some individual subjects. We expect that other fMRI centres will find this approach to identifying and controlling scanner instabilities useful in similar studies

    Association between solar insolation and a history of suicide attempts in bipolar I disorder

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    In many international studies, rates of completed suicide and suicide attempts have a seasonal pattern that peaks in spring or summer. This exploratory study investigated the association between solar insolation and a history of suicide attempt in patients with bipolar I disorder. Solar insolation is the amount of electromagnetic energy from the Sun striking a surface area on Earth. Data were collected previously from 5536 patients with bipolar I disorder at 50 collection sites in 32 countries at a wide range of latitudes in both hemispheres. Suicide related data were available for 3365 patients from 310 onset locations in 51 countries. 1047 (31.1%) had a history of suicide attempt. There was a significant inverse association between a history of suicide attempt and the ratio of mean winter solar insolation/mean summer solar insolation. This ratio is smallest near the poles where the winter insolation is very small compared to the summer insolation. This ratio is largest near the equator where there is relatively little variation in the insolation over the year. Other variables in the model that were positively associated with suicide attempt were being female, a history of alcohol or substance abuse, and being in a younger birth cohort. Living in a country with a state-sponsored religion decreased the association. (All estimated coefficients p <0.01). In summary, living in locations with large changes in solar insolation between winter and summer may be associated with increased suicide attempts in patients with bipolar disorder. Further investigation of the impacts of solar insolation on the course of bipolar disorder is needed.Peer reviewe

    Will there be a role for neuroimaging in clinical psychiatry?

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    Prevalence of metabolic syndrome in never treated mood disordered patientss

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    Bipolar disorder and major depression are life-shortening illnesses. Unnatural causes such as suicide and accidents account for only a portion of this premature mortality1 Research is beginning to identify that mood disordered patients have a higher incidence of metabolic syndrome, an illness characterized by dyslipidemia, impaired glucose tolerance, hypertension and obesity.2 Metabolic syndrome is associated with an increased risk for a variety of physical illnesses. Hypothesis: Never treated patients with mood disorders have preexisting elevations in the prevalence of the component variables of metabolic syndrome. Central obesity will be especially elevated, predicting increased premature mortality. Methods: We assessed never treated patients with mood disorders for metabolic syndrome and its component variables. Patients were assessed at baseline and followed up at 6-month intervals. All psychiatric pharmacotherapy was documented. Body mass index (BMI) was also obtained and the percentage of deaths attributable to overweight and obesity was calculated using the population attributable risk (PAR). [PAR= &#8721;[P (RR-1)/RR] Results: Prior to the initiation of treatment, patients did not differ from population norms with respect to metabolic syndrome or BMI. At 2-year follow-up, BMI had increased for unipolar patients 2.02 points and 1.92 points for bipolar patients. (p < .001) This increase in BMI predicted an increase in mortality of 19.4%. Conclusion: An increase in visceral obesity is often the first component of metabolic syndrome to appear and may indicate the initiation of this disease process prematurely in this group. The increase in BMI places patients with mood disorders at risk for premature mortality and indicates a need for early intervention. References 1.Osby U, Brandt L, Correia N, Ekbom A & Sparen P. Excess mortability in bipolar and Unipolar disorder rin Sweden. Archives of General Psychiatry, 2001;58: 844-850 2.Toalson P, Saeeduddin A, Hardy T & Kabinoff G. The metabolic syndrome in patients with severe mental illness. Journal of Clinical Psychiatry, 2004; 6(4): 152-15

    The Role of Adipokines in Understanding the Associations between Obesity and Depression

    No full text
    Objective. Two major causes of disability, major depression and obesity, share overlapping psychosocial and pathophysiological etiologies. Studies are now focused on biological mechanisms linking the two illnesses, and there is interest in the role that adipokines may have in mediating the association between obesity and depression. We reviewed the literature to look at what is currently known about this association, focusing on the adipokines leptin, adiponectin, and resistin. Methods. A MEDLINE search, citing articles from 1966 onward, supplemented by a review of bibliographies, was conducted to identify relevant studies. Results. This paper identified plausible pathways underlying a link between adipokines and depression. Only a few studies have yet been conducted specifically examining these biomarkers in patients with depression, but the results are intriguing. Conclusion. This paper is one of the first to examine the association between adipokines and depression. It provides an overview of the physiological role of adipokines and summarizes the data suggesting that they may be dysregulated in major depression. This area of research may become increasingly important as new treatment strategies are developed.Peer Reviewe
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