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Find video protocols related to scientific articles indexed in Pubmed.
Thalamocortical abnormalities in auditory brainstem response patterns distinguish DSM-IV bipolar disorder type I from schizophrenia.
J Affect Disord
PUBLISHED: 08-13-2014
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Bipolar disorder type I (BP-I) belongs to a spectrum of affective disorders that are expressed in many different ways and therefore can be difficult to distinguish from other conditions, especially unipolar depression, schizoaffective disorder, schizophrenia (SZ), but also anxiety and personality disorders. Since early diagnosis and treatment have shown to improve the long-term prognosis, complementary specific biomarkers are of great value. The auditory brainstem response (ABR) has previously been applied successfully to identify specific abnormal ABR patterns in SZ and Asperger syndrome.
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Serum metabolomic biomarkers of dementia.
Dement Geriatr Cogn Dis Extra
PUBLISHED: 07-11-2014
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This study compared serum metabolites of demented patients (Alzheimer's disease and vascular dementia) and controls, and explored serum metabolite profiles of nondemented individuals 5 years preceding the diagnosis.
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Reactivated herpes simplex infection increases the risk of Alzheimer's disease.
Alzheimers Dement
PUBLISHED: 03-06-2014
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Previous studies have suggested a link between herpes simplex virus (HSV) type 1 and the development of Alzheimer's disease (AD).
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Lack of association of the rs1344706 ZNF804A variant with cognitive functions and DTI indices of white matter microstructure in two independent healthy populations.
Psychiatry Res
PUBLISHED: 02-10-2014
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The rs1344706 single nucleotide polymorphism within intron 2 of the ZNF804A gene is strongly associated with schizophrenia and bipolar disorder. This variant has also been associated in some studies with a range of cognitive and neuroimaging phenotypes, but several studies have reported no effect on the same phenotypes in other samples. Here, we genotyped 670 healthy adult Norwegian subjects and 1753 healthy adult Swedish subjects for rs1344706, and tested for associations with cognitive phenotypes including general intellectual abilities, memory functions and cognitive inhibition. We also tested whether rs1344706 is associated with white matter microstructural properties using diffusion tensor imaging (DTI) data from 250 to 340 of the Norwegian and Swedish subjects, respectively. Whole-brain voxel-wise statistical modeling of the effect of the ZNF804A variant on two DTI indices, fractional anisotropy (FA) and radial diffusivity (RD), was performed using tract-based spatial statistics (TBSS), and commonly reported effect sizes were calculated within several large-scale white matter pathways based on neuroanatomical atlases. No significant associations were found between rs1344706 and the cognitive traits or white matter microstructure. We conclude that the rs1344706 SNP has no significant effect on these phenotypes in our two reasonably powered samples.
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Olfactory impairment and subjective olfactory complaints independently predict conversion to dementia: a longitudinal, population-based study.
J Int Neuropsychol Soc
PUBLISHED: 01-22-2014
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We examined whether conversion to dementia can be predicted by self-reported olfactory impairment and/or by an inability to identify odors. Common forms of dementia involve an impaired sense of smell, and poor olfactory performance predicts cognitive decline among the elderly. We followed a sample of 1529 participants, who were within a normal range of overall cognitive function at baseline, over a 10-year period during which 159 were classified as having a dementia disorder. Dementia conversion was predicted from demographic variables, Mini-Mental State Examination score, and olfactory assessments. Self-reported olfactory impairment emerged as an independent predictor of dementia. After adjusting for effects of other predictors, individuals who rated their olfactory sensitivity as "worse than normal" were more likely to convert to dementia than those who reported normal olfactory sensitivity (odds ratio [OR] = 2.17; 95% confidence interval [CI] [1.40, 3.37]). Additionally, low scores on an odor identification test also predicted conversion to dementia (OR per 1 point increase = 0.89; 95% CI [0.81, 0.98]), but these two effects were additive. We suggest that assessing subjective olfactory complaints might supplement other assessments when evaluating the risk of conversion to dementia. Future studies should investigate which combination of olfactory assessments is most useful in predicting dementia conversion.
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The relationship between marital and parental status and the risk of dementia.
Int Psychogeriatr
PUBLISHED: 01-22-2014
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This study examines the association between marital and parental status and their individual and combined effect on risk of dementia diseases in a population-based longitudinal study while controlling for a range of potential confounders, including social networks and exposure to stressful negative life events.
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Relative hypo- and hypercortisolism are both associated with depression and lower quality of life in bipolar disorder: a cross-sectional study.
PLoS ONE
PUBLISHED: 01-01-2014
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Depression in unipolar and bipolar disorders is associated with hypothalamic-pituitary-adrenal-axis (HPA-axis) hyperactivity. Also, unipolar disorder has recently been shown to exhibit HPA-axis hypoactivity. We studied for the first time how HPA-axis hypo- and hyperactivity relate to depression and disease burden in bipolar disorder. We were interested in studying hypocortisolism; characterized by increased HPA-axis negative feedback sensitivity and lower basal cortisol levels together with the opposite HPA-axis regulatory pattern of hypercortisolism.
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Shorter telomere length is linked to brain atrophy and white matter hyperintensities.
Age Ageing
PUBLISHED: 11-14-2013
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leukocyte telomere length (TL) is considered a marker of biological aging. Several studies have investigated the link between leukocyte TL and aging-associated functional attributes of the brain, but no prior study has investigated whether TL can be linked to brain atrophy and white matter hyperintensities (WMHs); two prominent structural manifestations of brain aging.
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Stressful life events are not associated with the development of dementia.
Int Psychogeriatr
PUBLISHED: 11-04-2013
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ABSTRACT Background: The impact of stressful life events as a risk factor of dementia diseases is inconclusive. We sought to determine whether stressful negative life events are associated with incidental dementia in a population-based study with long-term follow-up. We also tested the hypothesis that the occurrence of positive life events could mitigate or overcome the possible adverse effects of negative life events on dementia conversion. Methods: The study involved 2,462 dementia-free participants aged 55 years and older. Information on life events was ascertained at baseline from a comprehensive Life Event Inventory, which included 56 questions about specific life events. For each life event, the emotional impact (both positive and negative) and emotional adjustment were asked for. Results: During follow-up, 423 participants developed dementia; of these, 240 developed Alzheimers disease (AD). Cox regression analysis showed no association between the total number of negative life events and the incidence of dementia when adjusted solely for age and gender (hazard ratio = 0.97, 95% CI = 0.92-1.02), or with multiple adjustments for a range of covariates (hazard ratio = 0.96, 95% CI = 0.91-1.01). Similarly, neither emotional impact nor emotional adjustment to these life events was associated with incident dementia. A separate analysis of AD did not alter the results. Conclusions: The result of this population-based study finds no association between negative or positive life events and dementia. Accordingly, our results reject the hypothesis that stressful life events trigger the onset of dementia diseases.
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Leisure Activity in Old Age and Risk of Dementia: A 15-Year Prospective Study.
J Gerontol B Psychol Sci Soc Sci
PUBLISHED: 06-13-2013
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Objectives.The aim of this study was to investigate whether leisure activity is associated with incident dementia in an older sample.Method.We examined a sample of 1,475 elderly (? 65 years) who were dementia free at baseline over a follow-up period of up to 15 years. In addition to analyses involving the total time period, separate analyses of three time periods were performed, 1-5, 6-10, and 11-15 years, following baseline measurement of leisure activity. RESULTS: After controlling for a variety of potential confounders, analyses of data for the total time period revealed that higher levels of "Total activity" and "Social activity," but not "Mental activity," were associated with decreased risk of dementia. However, analyses of the separate time periods showed that this association was only significant in the first time period, 1-5 years after baseline.Discussion.The results from this study provide little support for the hypothesis that frequent engagement in leisure activities among elderly serve to protect against dementia diseases across a longer time frame. The finding of a relationship for the first time period, 1-5 years after baseline, could indicate short-term protective effects but could also reflect reverse causality.
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Evidence for the involvement of the glucocorticoid receptor gene in bipolar disorder in an isolated northern Swedish population.
Bipolar Disord
PUBLISHED: 11-17-2011
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Dysfunction of the hypothalamus-pituitary-adrenal (HPA) axis is one of the most consistent findings in the pathophysiology of mood disorders. The potential role of genes related to HPA axis function has been investigated extensively in major depression. However, in bipolar disorder (BPD) such studies are scarce. We performed a systematic HapMap-based association study of six genes crucial for HPA axis function in relation to BPD.
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KIBRA polymorphism is related to enhanced memory and elevated hippocampal processing.
J. Neurosci.
PUBLISHED: 10-07-2011
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Several studies have linked the KIBRA rs17070145 T polymorphism to superior episodic memory in healthy humans. One study investigated the effect of KIBRA on brain activation patterns (Papassotiropoulos et al., 2006) and observed increased hippocampal activation in noncarriers of the T allele during retrieval. Noncarriers were interpreted to need more hippocampal activation to reach the same performance level as T carriers. Using large behavioral (N = 2230) and fMRI (N = 83) samples, we replicated the KIBRA effect on episodic memory performance, but found increased hippocampal activation in T carriers during episodic retrieval. There was no evidence of compensatory brain activation in noncarriers within the hippocampal region. In the main fMRI sample, T carriers performed better than noncarriers during scanning but, importantly, the difference in hippocampus activation remained after post hoc matching according to performance, sex, and age (N = 64). These findings link enhanced memory performance in KIBRA T allele carriers to elevated hippocampal functioning, rather than to neural compensation in noncarriers.
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Short telomeres in depression and the general population are associated with a hypocortisolemic state.
Biol. Psychiatry
PUBLISHED: 07-09-2011
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The hypothalamic-pituitary-adrenal (HPA) axis plays a central role in stress regulation, and leukocyte telomere length (TL) has been suggested to represent a cumulative measure of stress. Depression is intimately related with stress and frequently exhibits a dysregulated HPA axis. We aimed to study the relationships between TL and biological and psychological facets of stress in recurrent major depressive disorder and controls.
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Sequencing of DISC1 pathway genes reveals increased burden of rare missense variants in schizophrenia patients from a northern Swedish population.
PLoS ONE
PUBLISHED: 03-17-2011
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In recent years, DISC1 has emerged as one of the most credible and best supported candidate genes for schizophrenia and related neuropsychiatric disorders. Furthermore, increasing evidence--both genetic and functional--indicates that many of its protein interaction partners are also involved in the development of these diseases. In this study, we applied a pooled sample 454 sequencing strategy, to explore the contribution of genetic variation in DISC1 and 10 of its interaction partners (ATF5, Grb2, FEZ1, LIS-1, PDE4B, NDE1, NDEL1, TRAF3IP1, YWHAE, and ZNF365) to schizophrenia susceptibility in an isolated northern Swedish population. Mutation burden analysis of the identified variants in a population of 486 SZ patients and 514 control individuals, revealed that non-synonymous rare variants with a MAF<0.01 were significantly more present in patients compared to controls (8.64% versus 4.7%, P?=?0.018), providing further evidence for the involvement of DISC1 and some of its interaction partners in psychiatric disorders. This increased burden of rare missense variants was even more striking in a subgroup of early onset patients (12.9% versus 4.7%, P?=?0.0004), highlighting the importance of studying subgroups of patients and identifying endophenotypes. Upon investigation of the potential functional effects associated with the identified missense variants, we found that ?90% of these variants reside in intrinsically disordered protein regions. The observed increase in mutation burden in patients provides further support for the role of the DISC1 pathway in schizophrenia. Furthermore, this study presents the first evidence supporting the involvement of mutations within intrinsically disordered protein regions in the pathogenesis of psychiatric disorders. As many important biological functions depend directly on the disordered state, alteration of this disorder in key pathways may represent an intriguing new disease mechanism for schizophrenia and related neuropsychiatric diseases. Further research into this unexplored domain will be required to elucidate the role of the identified variants in schizophrenia etiology.
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The relationship between the val158met catechol-O-methyltransferase (COMT) polymorphism and irritable bowel syndrome.
PLoS ONE
PUBLISHED: 02-22-2011
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The catechol-O-methyltransferase (COMT) enzyme has a key function in the degradation of catecholamines and a functional polymorphism is val158met. The val/val genotype results in a three to fourfold higher enzymatic activity compared with the met/met genotype, with the val/met genotype exhibiting intermediate activity. Since pain syndromes as well as anxiety and depression are associated to low and high COMT activity respectively and these conditions are all associated with irritable bowel syndrome (IBS) we wanted for the first time to explore the relationship between the polymorphism and IBS.
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Dual association of a TRKA polymorphism with schizophrenia.
Psychiatr. Genet.
PUBLISHED: 02-15-2011
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An interaction between predisposing genes and environmental stressors is thought to underlie the neurodevelopmental disorder schizophrenia. In a targeted gene screening, we previously found that the minor allele of the single nucleotide polymorphism (SNP) rs6336 in the neurotrophic tyrosine kinase receptor 1 (NTRK1/TRKA) gene is associated with schizophrenia as a risk factor.
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Swedish clinical guidelines--prevention and management of metabolic risk in patients with severe psychiatric disorders.
Nord J Psychiatry
PUBLISHED: 07-29-2010
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Individuals with severe psychiatric disorders are more likely than the population at large to develop metabolic derangements such as overweight and diabetes. Cardiovascular disease is also more frequently seen in this group. Contributing factors may include inappropriate diet or lack of physical activity, but antipsychotic medication may also play a role. Seven Swedish specialist medical societies have collaborated in formulating a set of concise clinically applicable guidelines-reproduced here in modified form-for the prevention and management of metabolic risk in this patient group. The importance of implementation is emphasized.
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Preliminary evidence that polymorphisms in dopamine-related transcription factors LMX1A, LMX1B and PITX3 are associated with schizophrenia.
Prog. Neuropsychopharmacol. Biol. Psychiatry
PUBLISHED: 05-26-2010
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The early development of dopaminergic pathways has been attributed importance for the aetiology of schizophrenia. Several transcription factors are involved in the survival and maturation of dopamine neurons, including LMX1A, LMX1B and PITX3. The possibility that polymorphisms in these genes may influence the development and/or the maintenance of dopaminergic neurons prompted us to investigate if five single nucleotide polymorphisms (SNPs) previously linked to Parkinsons disease are associated with this disorder. Preliminary evidence that genetic variation in LMX1A (rs6668493, rs4657411), LMX1B (rs10987386) and PITX3 (rs4919621) may increase the risk of developing schizophrenia is presented.
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Two-year outcome of vagus nerve stimulation in treatment-resistant depression.
J Clin Psychopharmacol
PUBLISHED: 05-18-2010
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One of the major goals of antidepressant treatment is a sustained response and remission of depressive symptoms. Some of the previous studies of vagus nerve stimulation (VNS) have suggested antidepressant effects. Our naturalistic study assessed the efficacy and the safety of VNS in 74 European patients with therapy-resistant major depressive disorder. Psychometric measures were obtained after 3, 12, and 24 months of VNS. Mixed-model repeated-measures analysis of variance revealed a significant reduction (P < or = 0.05) at all the 3 time points in the 28-item Hamilton Rating Scale for Depression (HRSD28) score, the primary outcome measure. After 2 years, 53.1% (26/49) of the patients fulfilled the response criteria (> or =50% reduction in the HRSD28 scores from baseline) and 38.9% (19/49) fulfilled the remission criteria (HRSD28 scores < or = 10). The proportion of patients who fulfilled the remission criteria remained constant as the duration of VNS treatment increased. Voice alteration, cough, and pain were the most frequently reported adverse effects. Two patients committed suicide during the study; no other deaths were reported. No statistically significant differences were seen in the number of concomitant antidepressant medications. The results of this 2-year open-label trial suggest a clinical response and a comparatively benign adverse effect profile among patients with treatment-resistant depression.
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PCM1 and schizophrenia: a replication study in the Northern Swedish population.
Am. J. Med. Genet. B Neuropsychiatr. Genet.
PUBLISHED: 05-15-2010
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Previous studies implicated centrosomal dysfunction as a source of various neuropsychiatric disorders, including schizophrenia (SZ). Two recent reports [Gurling et al., 2006; Datta et al., 2008. Mol Psychiatry] described an association between polymorphisms in the PCM1 gene and SZ in a UK/Scottish population. In this study, we aimed to replicate these findings in a Northern Swedish association sample of 486 research subjects with SZ and 512 unrelated control individuals. We genotyped 12 previously described SNP markers and carried out haplotype analyses using the same multi-marker haplotypes previously reported. Though we could not replicate the association with SNPs rs445422 and rs208747, we did observe a significant protective association with intronic SNP rs13276297. Furthermore, we performed a meta-analysis comprising 1,794 SZ patients and 1,553 controls, which confirmed the previously reported association with rs445422 and rs208747. These data provide further evidence that PCM1-though certainly not a major risk factor in the Northern Swedish population-cannot be ruled out as a contributor to SZ risk and/or protection, and deserves further replication in larger populations to elucidate its role in disease etiology.
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Hypomania: a transcultural perspective.
World Psychiatry
PUBLISHED: 02-12-2010
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This study examined the transcultural robustness of a screening instrument for hypomania, the Hypomania Checklist-32, first revised version (HCL-32 R1). It was carried out in 2606 patients from twelve countries in five geographic regions (Northern, Southern and Eastern Europe, South America and East Asia). In addition, GAMIAN Europe contributed data from its members. Exploratory and confirmatory factor analyses were used to examine the transregional stability of the measurement properties of the HCL-32 R1, including the influence of sex and age as covariates. Across cultures, a two-factor structure was confirmed: the first factor (F1) reflected the more positive aspects of hypomania (being more active, elated, self-confident, and cogni-tively enhanced); the second factor (F2) reflected the more negative aspects (being irritable, impulsive, careless, more substance use). The measurement properties of the HCL-32 R1 were largely invariant across cultures. Only few items showed transcultural differences in their relation to hypomania as measured by the test. F2 was higher among men and in more severe manic syndromes; F1 was highest in North and East Europe and lowest in South America. The scores decreased slightly with age. The frequency of the 32 items showed remarkable similarities across geographic areas, with two excep-tions: South Europeans had lower symptom frequencies in general and East Europeans higher rates of substance use. These findings support the interna-tional applicability of the HCL-32 R1 as a screening instrument for hypomania.
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APOE ?4 is associated with longer telomeres, and longer telomeres among ?4 carriers predicts worse episodic memory.
Neurobiol. Aging
PUBLISHED: 02-05-2010
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Both leukocyte telomere length and the apolipoprotein ?4 allele have been associated with mortality, cardiovascular disease, cognition, and dementia. The authors investigated whether leukocyte telomere length was associated with APOE genotype or cognitive abilities in the context of APOE genotype. The setting for this cross-sectional study was 427 nondemented individuals aged 41-81 yr. The authors found that ?4 carriers overall exhibited significantly longer telomeres compared with non-carriers (difference of 268 bp, p = 0.001). This difference was greatest at the lower limit of the age span and nonsignificant at the upper limit, which translated into a significantly higher telomere attrition rate (p = 0.049) among ?4 carriers (37 bp/years) compared with non-carriers (21 bp/year). Further, longer telomeres among ?4 carriers significantly predicted worse performance on episodic memory tasks. No significant associations were found on tasks tapping semantic and visuospatial ability, or among ?3/?3 carriers. In conclusion, APOE ?4 carriers had longer telomeres compared with non-carriers, but higher rate of attrition. Among them, longer telomeres predicted worse performance on episodic memory tasks. These observations suggest that the ?4 allele is associated with abnormal cell turnover of functional and possibly clinical significance.
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CRY2 is associated with depression.
PLoS ONE
PUBLISHED: 02-01-2010
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Abnormalities in the circadian clockwork often characterize patients with major depressive and bipolar disorders. Circadian clock genes are targets of interest in these patients. CRY2 is a circadian gene that participates in regulation of the evening oscillator. This is of interest in mood disorders where a lack of switch from evening to morning oscillators has been postulated.
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Large-scale parent-child comparison confirms a strong paternal influence on telomere length.
Eur. J. Hum. Genet.
PUBLISHED: 10-14-2009
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Telomere length is documented to have a hereditary component, and both paternal and X-linked inheritance have been proposed. We investigated blood cell telomere length in 962 individuals with an age range between 0 and 102 years. Telomere length correlations were analyzed between parent-child pairs in different age groups and between grandparent-grandchild pairs. A highly significant correlation between the fathers and the childs telomere length was observed (r=0.454, P<0.001), independent of the sex of the offspring (father-son: r=0.465, P<0.001; father-daughter: r=0.484, P<0.001). For mothers, the correlations were weaker (mother-child: r=0.148, P=0.098; mother-son: r=0.080, P=0.561; mother-daughter: r=0.297, P=0.013). A positive telomere length correlation was also observed for grandparent-grandchild pairs (r=0.272, P=0.013). Our findings indicate that fathers contribute significantly stronger to the telomere length of the offspring compared with mothers (P=0.012), but we cannot exclude a maternal influence on the daughters telomeres. Interestingly, the father-child correlations diminished with increasing age (P=0.022), suggesting that nonheritable factors have an impact on telomere length dynamics during life.
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Support for NRG1 as a susceptibility factor for schizophrenia in a northern Swedish isolated population.
Arch. Gen. Psychiatry
PUBLISHED: 08-05-2009
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Neuregulin 1 (NRG1), a growth factor involved in neurodevelopment, myelination, neurotransmitter receptor expression, and synaptic plasticity, first joined the list of candidate genes for schizophrenia when a 7-marker haplotype at the 5 end of the gene (Hap(ICE)) was shown to be associated with the disorder in the Icelandic population. Since then, more genetic and functional evidence has emerged, which supports a role for NRG1 in the development of schizophrenia.
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Detailed analysis of the serotonin transporter gene (SLC6A4) shows no association with bipolar disorder in the Northern Swedish population.
Am. J. Med. Genet. B Neuropsychiatr. Genet.
PUBLISHED: 07-31-2009
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Through active reuptake of serotonin into presynaptic neurons, the serotonin transporter (5-HTT) plays an important role in regulating serotonin concentrations in the brain, and it is the site of binding for tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs). Therefore it has been hypothesized that this transporter is involved in the etiology of bipolar (BP) disorder. Inconsistent association study results for the SLC6A4 gene encoding 5-HTT reported in literature emphasize the need for more systematic and detailed analyses of this candidate gene. We performed an extensive analysis of SLC6A4 on DNA of 254 BPI patients and 364 control individuals from a Northern Swedish isolated population. This analysis consisted of a HapMap LD-based association study including three widely investigated polymorphisms (5-HTTVNTR, 5-HTTLPR, and rs3813034), a copy-number variation (CNV) analysis and a mutation analysis of the complete coding sequence and the 3-UTR of SLC6A4. No single marker showed statistically significant association with BPI, nor did any of the haplotypes. In the mutation analysis 13 novel variants were detected, including 2 amino acid substitutions M389V and I587L, but these are probably not implicated in risk for BP. No deletions or duplications were detected in the CNV analysis. We conclude that variation in the SLC6A4 gene or its regulatory regions does not contribute to the susceptibility for BP disorder in the Northern Swedish population.
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Personality traits predict response to novel and familiar stimuli in the hippocampal region.
Psychiatry Res
PUBLISHED: 06-21-2009
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Current evidence from genetic, neurochemical, and clinical research supports the notion that a combination of high novelty seeking and low harm avoidance traits (NS-ha) is reliably dissociable from the opposite personality profile (i.e., low novelty seeking and high harm avoidance, ns-HA). Little is known, however, about how the differences between these two types of personality are regulated by brain function. Here we used functional magnetic resonance imaging (fMRI) and recruited two groups of individuals, one group with the NS-ha profile and the other group with the ns-HA profile, to examine whether there is a difference between the two groups in their brain response to novel versus familiar word stimuli. Results revealed a differential pattern of response in an area in the hippocampal region, with the NS-ha group showing a greater sensitivity to novel stimuli and the ns-HA group demonstrating a greater response to familiar stimuli. We conclude that the response pattern to novel and familiar stimuli in the hippocampal region has a role in mediating differences between the NS-ha and ns-HA temperamental profiles.
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The individual blood cell telomere attrition rate is telomere length dependent.
PLoS Genet.
PUBLISHED: 01-09-2009
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Age-associated telomere shortening is a well documented feature of peripheral blood cells in human population studies, but it is not known to what extent these data can be transferred to the individual level. Telomere length (TL) in two blood samples taken at approximately 10 years interval from 959 individuals was investigated using real-time PCR. TL was also measured in 13 families from a multigenerational cohort. As expected, we found an age-related decline in TL over time (r = -0.164, P<0.001, n = 959). However, approximately one-third of the individuals exhibited a stable or increased TL over a decade. The individual telomere attrition rate was inversely correlated with initial TL at a highly significant level (r = -0.752, P<0.001), indicating that the attrition rate was most pronounced in individuals with long telomeres at baseline. In accordance, the age-associated telomere attrition rate was more prominent in families with members displaying longer telomeres at a young age (r = -0.691, P<0.001). Abnormal blood TL has been reported at diagnosis of various malignancies, but in the present study there was no association between individual telomere attrition rate or prediagnostic TL and later tumor development. The collected data strongly suggest a TL maintenance mechanism acting in vivo, providing protection of short telomeres as previously demonstrated in vitro. Our findings might challenge the hypothesis that individual TL can predict possible life span or later tumor development.
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Decreased medial temporal lobe activation in BDNF (66)Met allele carriers during memory encoding.
Neuropsychologia
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The Met allele of the Brain-derived neurotrophic factor (BDNF) Val(66)Met polymorphism has been associated with impaired activity-dependent secretion of BDNF protein and decreased memory performance. Results from imaging studies relating Val(66)Met to brain activation during memory processing have been inconsistent, with reports of both increased and decreased activation in the Medial Temporal Lobe (MTL) in Met carriers relative to Val homozygotes. Here, we extensively studied BDNF Val(66)Met in relation to brain activation and white matter integrity as well as memory performance in a large imaging (n=194) and behavioral (n=2229) sample, respectively. Functional magnetic resonance imaging (fMRI) was used to investigate MTL activation in healthy participants in the age of 55-75 years during a face-name episodic encoding and retrieval task. White matter integrity was measured using diffusion tensor imaging. BDNF Met allele carriers had significantly decreased activation in the MTL during encoding processes, but not during retrieval processes. In contrast to previous proposals, the effect was not modulated by age and the polymorphism was not related to white matter integrity. Met carriers had lower memory performance than Val homozygotes, but differences were subtle and not significant. In conclusion, the BDNF Met allele has a negative influence on MTL functioning, preferentially during encoding processes, which might translate into impaired episodic memory function.
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Rare copy number variants in neuropsychiatric disorders: Specific phenotype or not?
Am. J. Med. Genet. B Neuropsychiatr. Genet.
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From a number of genome-wide association studies it was shown that de novo and/or rare copy number variants (CNVs) are found at an increased frequency in neuropsychiatric diseases. In this study we examined the prevalence of CNVs in six genomic regions (1q21.1, 2p16.3, 3q29, 15q11.2, 15q13.3, and 16p11.2) previously implicated in neuropsychiatric diseases. Hereto, a cohort of four neuropsychiatric disorders (schizophrenia, bipolar disorder, major depressive disorder, and intellectual disability) and control individuals from three different populations was used in combination with Multilpex Amplicon Quantifiaction (MAQ) assays, capable of high resolution (kb range) and custom-tailored CNV detection. Our results confirm the etiological candidacy of the six selected CNV regions for neuropsychiatric diseases. It is possible that CNVs in these regions can result in disturbed brain development and in this way lead to an increased susceptibility for different neuropsychiatric disorders, dependent on additional genetic and environmental factors. Our results also suggest that the neurodevelopmental component is larger in the etiology of schizophrenia and intellectual disability than in mood disorders. Finally, our data suggest that deletions are in general more pathogenic than duplications. Given the high frequency of the examined CNVs (1-2%) in patients of different neuropsychiatric disorders, screening of large cohorts with an affordable and feasible method like the MAQ assays used in this study is likely to result in important progress in unraveling the genetic factors leading to an increased susceptibility for several psychiatric disorders.
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Longer leukocyte telomere length is associated with smaller hippocampal volume among non-demented APOE ?3/?3 subjects.
PLoS ONE
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Telomere length shortens with cellular division, and leukocyte telomere length is used as a marker for systemic telomere length. The hippocampus hosts adult neurogenesis and is an important structure for episodic memory, and carriers of the apolipoprotein E ?4 allele exhibit higher hippocampal atrophy rates and differing telomere dynamics compared with non-carriers. The authors investigated whether leukocyte telomere length was associated with hippocampal volume in 57 cognitively intact subjects (29 ?3/?3 carriers; 28 ?4 carriers) aged 49-79 yr. Leukocyte telomere length correlated inversely with left (r(s)?=?-0.465; p?=?0.011), right (r(s)?=?-0.414; p?=?0.025), and total hippocampus volume (r(s)?=?-0.519; p?=?0.004) among APOE ?3/?3 carriers, but not among ?4 carriers. However, the ?4 carriers fit with the general correlation pattern exhibited by the ?3/?3 carriers, as ?4 carriers on average had longer telomeres and smaller hippocampi compared with ?3/?3 carriers. The relationship observed can be interpreted as long telomeres representing a history of relatively low cellular proliferation, reflected in smaller hippocampal volumes. The results support the potential of leukocyte telomere length being used as a biomarker for tapping functional and structural processes of the aging brain.
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Identification of a CACNA2D4 deletion in late onset bipolar disorder patients and implications for the involvement of voltage-dependent calcium channels in psychiatric disorders.
Am. J. Med. Genet. B Neuropsychiatr. Genet.
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The GWAS-based association of CACNA1C with bipolar disorder (BPD) is one of the strongest genetic findings to date. CACNA1C belongs to the family of CACN genes encoding voltage-dependent calcium channels (VDCCs). VDCCs are involved in brain circuits and cognitive processes implicated in BPD and schizophrenia (SZ). Recently, it was shown that rare copy number variations (CNVs) are found at an increased frequency in SZ and to a lesser extent also in BPD, suggesting the involvement of CNVs in the causation of these diseases. We hypothesize that CNVs in CACN genes can influence the susceptibility to BPD, SZ, and/or schizoaffective disorder (SZA). A search for CNVs in eight CACN genes in a patient-control sample of European decent was performed. A total of 709 BP patients, 645 SZ patients, 189 SZA patients, and 1,470 control individuals were screened using the Multiplex Amplicon Quantification (MAQ) method. We found a rare, partial deletion of 35.7 kb in CACNA2D4 in two unrelated late onset bipolar I patients and in one control individual. All three deletions shared the same breakpoints removing exons 17-26 of CACNA2D4, comprising part of the CACHE domain. Based on the data we cannot claim causality to BPD of the identified CACNA2D4 deletion but nevertheless this deletion can be important in unraveling the underlying processes leading to psychiatric diseases in general and BPD in particular.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.