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1.  Depression and attempted suicide under pregabalin therapy 
Originally developed for the treatment of epilepsy, pregabalin has become a compound with a wide spectrum of indications comprising anxiety disorders and chronic pain and is therefore largely prescribed. Thus, it is important for clinicians to be aware of rare, but serious adverse effects. The following report illustrates the case of a 20-year-old male with a severe depressive syndrome following pregabalin medication which even led to a suicide attempt.
doi:10.1186/s12991-014-0037-8
PMCID: PMC4258812  PMID: 25489334
Depression; Anticonvulsants; Suicide; Pregabalin
3.  The Role of Variation at AβPP, PSEN1, PSEN2, and MAPT in Late Onset Alzheimer’s Disease 
Gerrish, Amy | Russo, Giancarlo | Richards, Alexander | Moskvina, Valentina | Ivanov, Dobril | Harold, Denise | Sims, Rebecca | Abraham, Richard | Hollingworth, Paul | Chapman, Jade | Hamshere, Marian | Pahwa, Jaspreet Singh | Dowzell, Kimberley | Williams, Amy | Jones, Nicola | Thomas, Charlene | Stretton, Alexandra | Morgan, Angharad R. | Lovestone, Simon | Powell, John | Proitsi, Petroula | Lupton, Michelle K. | Brayne, Carol | Rubinsztein, David C. | Gill, Michael | Lawlor, Brian | Lynch, Aoibhinn | Morgan, Kevin | Brown, Kristelle S. | Passmore, Peter A. | Craig, David | McGuinness, Bernadette | Todd, Stephen | Johnston, Janet A. | Holmes, Clive | Mann, David | Smith, A. David | Love, Seth | Kehoe, Patrick G. | Hardy, John | Mead, Simon | Fox, Nick | Rossor, Martin | Collinge, John | Maier, Wolfgang | Jessen, Frank | Kölsch, Heike | Heun, Reinhard | Schürmann, Britta | van den Bussche, Hendrik | Heuser, Isabella | Kornhuber, Johannes | Wiltfang, Jens | Dichgans, Martin | Frölich, Lutz | Hampel, Harald | Hüll, Michael | Rujescu, Dan | Goate, Alison M. | Kauwe, John S. K. | Cruchaga, Carlos | Nowotny, Petra | Morris, John C. | Mayo, Kevin | Livingston, Gill | Bass, Nicholas J. | Gurling, Hugh | McQuillin, Andrew | Gwilliam, Rhian | Deloukas, Panagiotis | Davies, Gail | Harris, Sarah E. | Starr, John M. | Deary, Ian J. | Al-Chalabi, Ammar | Shaw, Christopher E. | Tsolaki, Magda | Singleton, Andrew B. | Guerreiro, Rita | Mühleisen, Thomas W. | Nöthen, Markus M. | Moebus, Susanne | Jöckel, Karl-Heinz | Klopp, Norman | Wichmann, H-Erich | Carrasquillo, Minerva M | Pankratz, V Shane | Younkin, Steven G. | Jones, Lesley | Holmans, Peter A. | O’Donovan, Michael C. | Owen, Michael J. | Williams, Julie
Rare mutations in AβPP, PSEN1, and PSEN2 cause uncommon early onset forms of Alzheimer’s disease (AD), and common variants in MAPT are associated with risk of other neurodegenerative disorders. We sought to establish whether common genetic variation in these genes confer risk to the common form of AD which occurs later in life (>65 years). We therefore tested single-nucleotide polymorphisms at these loci for association with late-onset AD (LOAD) in a large case-control sample consisting of 3,940 cases and 13,373 controls. Single-marker analysis did not identify any variants that reached genome-wide significance, a result which is supported by other recent genome-wide association studies. However, we did observe a significant association at the MAPT locus using a gene-wide approach (p = 0.009). We also observed suggestive association between AD and the marker rs9468, which defines the H1 haplotype, an extended haplotype that spans the MAPT gene and has previously been implicated in other neurodegenerative disorders including Parkinson’s disease, progressive supranuclear palsy, and corticobasal degeneration. In summary common variants at AβPP, PSEN1, and PSEN2 and MAPT are unlikely to make strong contributions to susceptibility for LOAD. However, the gene-wide effect observed at MAPT indicates a possible contribution to disease risk which requires further study.
doi:10.3233/JAD-2011-110824
PMCID: PMC4118466  PMID: 22027014
Alzheimer’s disease; amyloid-β protein precursor; genetics; human; MAPT protein; PSEN1 protein; PSEN2 protein
4.  αCaMKII Autophosphorylation Controls the Establishment of Alcohol Drinking Behavior 
Neuropsychopharmacology  2013;38(9):1636-1647.
The α-Ca2+/calmodulin-dependent protein kinase II (αCaMKII) is a crucial enzyme controlling plasticity in the brain. The autophosphorylation of αCaMKII works as a ‘molecular memory' for a transient calcium activation, thereby accelerating learning. We investigated the role of αCaMKII autophosphorylation in the establishment of alcohol drinking as an addiction-related behavior in mice. We found that alcohol drinking was initially diminished in αCaMKII autophosphorylation-deficient αCaMKIIT286A mice, but could be established at wild-type level after repeated withdrawals. The locomotor activating effects of a low-dose alcohol (2 g/kg) were absent in αCaMKIIT286A mice, whereas the sedating effects of high-dose (3.5 g/kg) were preserved after acute and subchronic administration. The in vivo microdialysis revealed that αCaMKIIT286A mice showed no dopamine (DA) response in the nucleus accumbens to acute or subchronic alcohol administration, but enhanced serotonin (5-HT) responses in the prefrontal cortex. The attenuated DA response in αCaMKIIT286A mice was in line with altered c-Fos activation in the ventral tegmental area after acute and subchronic alcohol administration. In order to compare findings in mice with the human condition, we tested 23 single-nucleotide polymorphisms (SNPs) in the CAMK2A gene for their association with alcohol dependence in a population of 1333 male patients with severe alcohol dependence and 939 controls. We found seven significant associations between CAMK2A SNPs and alcohol dependence, one of which in an autophosphorylation-related area of the gene. Together, our data suggest αCaMKII autophosphorylation as a facilitating mechanism in the establishment of alcohol drinking behavior with changing the DA–5-HT balance as a putative mechanism.
doi:10.1038/npp.2013.60
PMCID: PMC3717547  PMID: 23459588
Alcohol & Alcoholism; alphaCaMKII; Animal models; autophosphorylation; c-Fos; Dopamine; microdialysis; Serotonin; αCaMKII; autophosphorylation; alcohol; reinforcement; dopamine; serotonin
5.  Dynamic Properties of the Alkaline Vesicle Population at Hippocampal Synapses 
PLoS ONE  2014;9(7):e102723.
In compensatory endocytosis, scission of vesicles from the plasma membrane to the cytoplasm is a prerequisite for intravesicular reacidification and accumulation of neurotransmitter molecules. Here, we provide time-resolved measurements of the dynamics of the alkaline vesicle population which appears upon endocytic retrieval. Using fast perfusion pH-cycling in live-cell microscopy, synapto-pHluorin expressing rat hippocampal neurons were electrically stimulated. We found that the relative size of the alkaline vesicle population depended significantly on the electrical stimulus size: With increasing number of action potentials the relative size of the alkaline vesicle population expanded. In contrast to that, increasing the stimulus frequency reduced the relative size of the population of alkaline vesicles. Measurement of the time constant for reacification and calculation of the time constant for endocytosis revealed that both time constants were variable with regard to the stimulus condition. Furthermore, we show that the dynamics of the alkaline vesicle population can be predicted by a simple mathematical model. In conclusion, here a novel methodical approach to analyze dynamic properties of alkaline vesicles is presented and validated as a convenient method for the detection of intracellular events. Using this method we show that the population of alkaline vesicles is highly dynamic and depends both on stimulus strength and frequency. Our results implicate that determination of the alkaline vesicle population size may provide new insights into the kinetics of endocytic retrieval.
doi:10.1371/journal.pone.0102723
PMCID: PMC4117485  PMID: 25079223
6.  Memory Concerns, Memory Performance and Risk of Dementia in Patients with Mild Cognitive Impairment 
PLoS ONE  2014;9(7):e100812.
Background
Concerns about worsening memory (“memory concerns”; MC) and impairment in memory performance are both predictors of Alzheimer's dementia (AD). The relationship of both in dementia prediction at the pre-dementia disease stage, however, is not well explored. Refined understanding of the contribution of both MC and memory performance in dementia prediction is crucial for defining at-risk populations. We examined the risk of incident AD by MC and memory performance in patients with mild cognitive impairment (MCI).
Methods
We analyzed data of 417 MCI patients from a longitudinal multicenter observational study. Patients were classified based on presence (n = 305) vs. absence (n = 112) of MC. Risk of incident AD was estimated with Cox Proportional-Hazards regression models.
Results
Risk of incident AD was increased by MC (HR = 2.55, 95%CI: 1.33–4.89), lower memory performance (HR = 0.63, 95%CI: 0.56–0.71) and ApoE4-genotype (HR = 1.89, 95%CI: 1.18–3.02). An interaction effect between MC and memory performance was observed. The predictive power of MC was greatest for patients with very mild memory impairment and decreased with increasing memory impairment.
Conclusions
Our data suggest that the power of MC as a predictor of future dementia at the MCI stage varies with the patients' level of cognitive impairment. While MC are predictive at early stage MCI, their predictive value at more advanced stages of MCI is reduced. This suggests that loss of insight related to AD may occur at the late stage of MCI.
doi:10.1371/journal.pone.0100812
PMCID: PMC4096405  PMID: 25019225
7.  Spot quantification in two dimensional gel electrophoresis image analysis: comparison of different approaches and presentation of a novel compound fitting algorithm 
BMC Bioinformatics  2014;15:181.
Background
Various computer-based methods exist for the detection and quantification of protein spots in two dimensional gel electrophoresis images. Area-based methods are commonly used for spot quantification: an area is assigned to each spot and the sum of the pixel intensities in that area, the so-called volume, is used a measure for spot signal. Other methods use the optical density, i.e. the intensity of the most intense pixel of a spot, or calculate the volume from the parameters of a fitted function.
Results
In this study we compare the performance of different spot quantification methods using synthetic and real data. We propose a ready-to-use algorithm for spot detection and quantification that uses fitting of two dimensional Gaussian function curves for the extraction of data from two dimensional gel electrophoresis (2-DE) images. The algorithm implements fitting using logical compounds and is computationally efficient. The applicability of the compound fitting algorithm was evaluated for various simulated data and compared with other quantification approaches. We provide evidence that even if an incorrect bell-shaped function is used, the fitting method is superior to other approaches, especially when spots overlap. Finally, we validated the method with experimental data of urea-based 2-DE of Aβ peptides andre-analyzed published data sets. Our methods showed higher precision and accuracy than other approaches when applied to exposure time series and standard gels.
Conclusion
Compound fitting as a quantification method for 2-DE spots shows several advantages over other approaches and could be combined with various spot detection methods.
The algorithm was scripted in MATLAB (Mathworks) and is available as a supplemental file.
doi:10.1186/1471-2105-15-181
PMCID: PMC4085234  PMID: 24915860
Two dimensional gel electrophoresis; Beta amyloid; Image analysis; Spot quantification
8.  Quantitative Validation of the n-Butanol Sniffin’ Sticks Threshold Pens 
Chemosensory Perception  2014;7(2):91-101.
Odorant pens are used by medical practitioners and researchers to assess olfactory dysfunction. Despite their routine use, there are currently no data on the gas-phase odorant concentrations released from the pen tips or whether these concentrations scale linearly with the aqueous-phase concentrations inside the pens. The commercially available Sniffin’ Sticks odor threshold test containing n-butanol was chosen for evaluation. The gas-phase concentration of n-butanol at the tip of each pen was measured directly in a new set of pens via proton-transfer-reaction mass spectrometry (PTR-MS). Measurements were additionally made on the same pens after 6 months and two older pen sets, namely a 3-year-old (used) and 4-year-old (new) set. Furthermore, application-related tests were made to determine the performance of the pens during routine use and under stress. These data demonstrate that the gas-phase n-butanol concentrations of the threshold pens are linear over the entire set, both for brand-new pens and 6 months later; this reflects the expected performance that was previously only assumed. Furthermore, the application–simulation tests demonstrated a good performance of the pens when used according to their intended protocol. Measurements of the older pen sets suggest that storage conditions are more critical than usage for pen stability. The present findings confirm that the n-butanol odorant pens are an appropriate tool for threshold testing, provided they are stored and handled correctly.
Figureᅟ
doi:10.1007/s12078-014-9168-1
PMCID: PMC4037591  PMID: 24883171
n-Butanol; Olfaction; PTR-MS; Sniffin’ Sticks; Odor threshold test
9.  Neuroanatomical Correlates of Intelligence in Healthy Young Adults: The Role of Basal Ganglia Volume 
PLoS ONE  2014;9(4):e93623.
Background
In neuropsychiatric diseases with basal ganglia involvement, higher cognitive functions are often impaired. In this exploratory study, we examined healthy young adults to gain detailed insight into the relationship between basal ganglia volume and cognitive abilities under non-pathological conditions.
Methodology/Principal Findings
We investigated 137 healthy adults that were between the ages of 21 and 35 years with similar educational backgrounds. Magnetic resonance imaging (MRI) was performed, and volumes of basal ganglia nuclei in both hemispheres were calculated using FreeSurfer software. The cognitive assessment consisted of verbal, numeric and figural aspects of intelligence for either the fluid or the crystallised intelligence factor using the intelligence test Intelligenz-Struktur-Test (I-S-T 2000 R). Our data revealed significant correlations of the caudate nucleus and pallidum volumes with figural and numeric aspects of intelligence, but not with verbal intelligence. Interestingly, figural intelligence associations were dependent on sex and intelligence factor; in females, the pallidum volumes were correlated with crystallised figural intelligence (r = 0.372, p = 0.01), whereas in males, the caudate volumes were correlated with fluid figural intelligence (r = 0.507, p = 0.01). Numeric intelligence was correlated with right-lateralised caudate nucleus volumes for both females and males, but only for crystallised intelligence (r = 0.306, p = 0.04 and r = 0.459, p = 0.04, respectively). The associations were not mediated by prefrontal cortical subfield volumes when controlling with partial correlation analyses.
Conclusions/Significance
The findings of our exploratory analysis indicate that figural and numeric intelligence aspects, but not verbal aspects, are strongly associated with basal ganglia volumes. Unlike numeric intelligence, the type of figural intelligence appears to be related to distinct basal ganglia nuclei in a sex-specific manner. Subcortical brain structures thus may contribute substantially to cognitive performance.
doi:10.1371/journal.pone.0093623
PMCID: PMC3974758  PMID: 24699871
10.  Common strength and localization of spontaneous and evoked synaptic vesicle release sites 
Molecular Brain  2014;7:23.
Background
Different pools and functions have recently been attributed to spontaneous and evoked vesicle release. Despite the well-established function of evoked release, the neuronal information transmission, the origin as well as the function of spontaneously fusing synaptic vesicles have remained elusive. Recently spontaneous release was found to e.g. regulate postsynaptic protein synthesis or has been linked to depressive disorder. Nevertheless the strength and cellular localization of this release form was neglected so far, which are both essential parameters in neuronal information processing.
Findings
Here we show that the complete recycling pool can be turned over by spontaneous trafficking and that spontaneous fusion rates critically depend on the neuronal localization of the releasing synapse. Thereby, the distribution equals that of evoked release so that both findings demonstrate a uniform regulation of these fusion modes.
Conclusions
In contrast to recent works, our results strengthen the assumption that identical vesicles are used for evoked and spontaneous release and extended the knowledge about spontaneous fusion with respect to its amount and cellular localization. Therefore our data supported the hypothesis of a regulatory role of spontaneous release in neuronal outgrowth and plasticity as neurites secrete neurotransmitters to initiate process outgrowth of a possible postsynaptic neuron to form a new synaptic connection.
doi:10.1186/1756-6606-7-23
PMCID: PMC4022376  PMID: 24694031
11.  Meconium Indicators of Maternal Alcohol Abuse during Pregnancy and Association with Patient Characteristics 
BioMed Research International  2014;2014:702848.
Aim. Identification of women with moderate alcohol abuse during pregnancy is difficult. We correlated self-reported alcohol consumption during pregnancy and patient characteristics with objective alcohol indicators measured in fetal meconium. Methods. A total of 557 women singleton births and available psychological tests, obstetric data and meconium samples were included in statistical analysis. Alcohol metabolites (fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG)), were determined from meconium and correlated with patient characteristics. Results. We found that 21.2% of the 557 participants admitted low-to-moderate alcohol consumption during pregnancy. Of the parameters analyzed from meconium, only EtG showed an association with alcohol history (P < 0.01). This association was inverse in cases with EtG value above 120 ng/g. These values indicate women with most severe alcohol consumption, who obviously denied having consumed alcohol during pregnancy. No other associations between socioeconomic or psychological characteristics and the drinking status (via meconium alcohol metabolites) could be found. Conclusion. Women who drink higher doses of ethanol during pregnancy, according to metabolite measures in meconium, might be less likely to admit alcohol consumption. No profile of socioeconomic or psychological characteristics of those women positively tested via meconium could be established.
doi:10.1155/2014/702848
PMCID: PMC3985164  PMID: 24800249
12.  Genetic Variants in the Genes of the Stress Hormone Signalling Pathway and Depressive Symptoms during and after Pregnancy 
BioMed Research International  2014;2014:469278.
Purpose. The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) in genes of the stress hormone signaling pathway, specifically FKBP5, NR3C1, and CRHR1, are associated with depressive symptoms during and after pregnancy. Methods. The Franconian Maternal Health Evaluation Study (FRAMES) recruited healthy pregnant women prospectively for the assessment of maternal and fetal health including the assessment of depressiveness. The German version of the 10-item Edinburgh Postnatal Depression Scale (EPDS) was completed at three time points in this prospective cohort study. Visit 1 was at study entry in the third trimester of the pregnancy, visit 2 was shortly after birth, and visit 3 was 6–8 months after birth. Germline DNA was collected from 361 pregnant women. Nine SNPs in the above mentioned genes were genotyped. After construction of haplotypes for each gene, a multifactorial linear mixed model was performed to analyse the depression values over time. Results. EPDS values were within expected ranges and comparable to previously published studies. Neither did the depression scores differ for comparisons among haplotypes at fixed time points nor did the change over time differ among haplotypes for the examined genes. No haplotype showed significant associations with depressive symptoms severity during pregnancy or the postpartum period. Conclusion. The analysed candidate haplotypes in FKBP5, NR3C1, and CRHR1 did not show an association with depression scores as assessed by EPDS in this cohort of healthy unselected pregnant women.
doi:10.1155/2014/469278
PMCID: PMC3972848  PMID: 24741566
13.  A progressive dopaminergic phenotype associated with neurotoxic conversion of α-synuclein in BAC-transgenic rats 
Brain  2013;136(2):412-432.
Conversion of soluble α-synuclein into insoluble and fibrillar inclusions is a hallmark of Parkinson’s disease and other synucleinopathies. Accumulating evidence points towards a relationship between its generation at nerve terminals and structural synaptic pathology. Little is known about the pathogenic impact of α-synuclein conversion and deposition at nigrostriatal dopaminergic synapses in transgenic mice, mainly owing to expression limitations of the α-synuclein construct. Here, we explore whether both the rat as a model and expression of the bacterial artificial chromosome construct consisting of human full-length wild-type α-synuclein could exert dopaminergic neuropathological effects. We found that the human promoter induced a pan-neuronal expression, matching the rodent α-synuclein expression pattern, however, with prominent C-terminally truncated fragments. Ageing promoted conversion of both full-length and C-terminally truncated α-synuclein species into insolube and proteinase K-resistant fibres, with strongest accumulation in the striatum, resembling biochemical changes seen in human Parkinson’s disease. Transgenic rats develop early changes in novelty-seeking, avoidance and smell before the progressive motor deficit. Importantly, the observed pathological changes were associated with severe loss of the dopaminergic integrity, thus resembling more closely the human pathology.
doi:10.1093/brain/aws358
PMCID: PMC3572936  PMID: 23413261
Parkinson’s disease; dopamine; animal models; alpha-synuclein; synapse function
14.  Catatonic Dilemma in a 33-Year-Old Woman: A Discussion 
Case Reports in Psychiatry  2013;2013:542303.
Case. We report a case of catatonia with elevated CK, elevated temperature, and hypoferritinemia after abrupt discontinuation of clozapine in a patient with known proneness to catatonic symptoms. Reinstatement of clozapine therapy was contraindicated due to leukopenia. Neuroleptic malign syndrome could not be ruled out by the administration of quetiapine; this prevented the quick use of other potent D2 antagonists. Some improvement was achieved through supportive therapy, high dose of lorazepam, and a series of 10 ECT sessions. Returning to baseline condition was achieved by a very careful increase of olanzapine. Discussion. Catatonic symptoms in schizophrenia as well as in NMS might be caused by a lack of striatal dopamine (CS) or dopamine D2 antagonism (NMS). CS might be a “special” kind of schizophrenia featuring both hypo- and hyperactivity of dopaminergic transmission. ECT has been described as a “psychic rectifier” or a “reset for the system.” The desirable effect of ECT in cases of CS might be dopaminergic stimulation in the striatum and decrease of both the dopaminergic activity in the limbic system and the serotonergic activity on 5-HT2 receptors. The desirable effect of ECT in NMS would be explained by activation of dopaminergic transmission and/or liberation of dopaminergic receptors from the causative neuroleptics.
doi:10.1155/2013/542303
PMCID: PMC3876715  PMID: 24416611
15.  Low 2D:4D Values Are Associated with Video Game Addiction 
PLoS ONE  2013;8(11):e79539.
Androgen-dependent signaling regulates the growth of the fingers on the human hand during embryogenesis. A higher androgen load results in lower 2D:4D (second digit to fourth digit) ratio values. Prenatal androgen exposure also impacts brain development. 2D:4D values are usually lower in males and are viewed as a proxy of male brain organization. Here, we quantified video gaming behavior in young males. We found lower mean 2D:4D values in subjects who were classified according to the CSAS-II as having at-risk/addicted behavior (n = 27) compared with individuals with unproblematic video gaming behavior (n = 27). Thus, prenatal androgen exposure and a hyper-male brain organization, as represented by low 2D:4D values, are associated with problematic video gaming behavior. These results may be used to improve the diagnosis, prediction, and prevention of video game addiction.
doi:10.1371/journal.pone.0079539
PMCID: PMC3827365  PMID: 24236143
16.  No consistent evidence for association between mtDNA variants and Alzheimer disease 
Hudson, G. | Sims, R. | Harold, D. | Chapman, J. | Hollingworth, P. | Gerrish, A. | Russo, G. | Hamshere, M. | Moskvina, V. | Jones, N. | Thomas, C. | Stretton, A. | Holmans, P.A. | O'Donovan, M.C. | Owen, M.J. | Williams, J. | Chinnery, P.F. | Harold, Denise | Abraham, Richard | Hollingworth, Paul | Sims, Rebecca | Gerrish, Amy | Chapman, Jade | Russo, Giancarlo | Hamshere, Marian | Pahwa, Jaspreet Singh | Moskvina, Valentina | Dowzell, Kimberley | Williams, Amy | Jones, Nicola | Thomas, Charlene | Stretton, Alexandra | Morgan, Angharad | Lovestone, Simon | Powell, John | Proitsi, Petroula | Lupton, Michelle K | Brayne, Carol | Rubinsztein, David C. | Gill, Michael | Lawlor, Brian | Lynch, Aoibhinn | Morgan, Kevin | Brown, Kristelle | Passmore, Peter | Craig, David | McGuinness, Bernadette | Todd, Stephen | Johnston, Janet | Holmes, Clive | Mann, David | Smith, A. David | Love, Seth | Kehoe, Patrick G. | Hardy, John | Mead, Simon | Fox, Nick | Rossor, Martin | Collinge, John | Maier, Wolfgang | Jessen, Frank | Heun, Reiner | Kölsch, Heike | Schürmann, Britta | van den Bussche, Hendrik | Heuser, Isabella | Kornhuber, Johannes | Wiltfang, Jens | Dichgans, Martin | Frölich, Lutz | Hampel, Harald | Hüll, Michael | Rujescu, Dan | Goate, Alison | Kauwe, John S.K. | Cruchaga, Carlos | Nowotny, Petra | Morris, John C. | Mayo, Kevin | Livingston, Gill | Bass, Nicholas J. | Gurling, Hugh | McQuillin, Andrew | Gwilliam, Rhian | Deloukas, Panagiotis | Holmans, Peter | O'Donovan, Michael | Owen, Michael J. | Williams, Julie
Neurology  2012;78(14):1038-1042.
Objective:
Although several studies have described an association between Alzheimer disease (AD) and genetic variation of mitochondrial DNA (mtDNA), each has implicated different mtDNA variants, so the role of mtDNA in the etiology of AD remains uncertain.
Methods:
We tested 138 mtDNA variants for association with AD in a powerful sample of 4,133 AD case patients and 1,602 matched controls from 3 Caucasian populations. Of the total population, 3,250 case patients and 1,221 elderly controls met the quality control criteria and were included in the analysis.
Results:
In the largest study to date, we failed to replicate the published findings. Meta-analysis of the available data showed no evidence of an association with AD.
Conclusion:
The current evidence linking common mtDNA variations with AD is not compelling.
doi:10.1212/WNL.0b013e31824e8f1d
PMCID: PMC3317529  PMID: 22442439
17.  Key Physiological Parameters Dictate Triggering of Activity-Dependent Bulk Endocytosis in Hippocampal Synapses 
PLoS ONE  2012;7(6):e38188.
To maintain neurotransmission in central neurons, several mechanisms are employed to retrieve synaptically exocytosed membrane. The two major modes of synaptic vesicle (SV) retrieval are clathrin-mediated endocytosis and activity-dependent bulk endocytosis (ADBE). ADBE is the dominant SV retrieval mode during intense stimulation, however the precise physiological conditions that trigger this mode are not resolved. To determine these parameters we manipulated rat hippocampal neurons using a wide spectrum of stimuli by varying both the pattern and duration of stimulation. Using live-cell fluorescence imaging and electron microscopy approaches, we established that stimulation frequency, rather than the stimulation load, was critical in the triggering of ADBE. Thus two hundred action potentials, when delivered at high frequency, were sufficient to induce near maximal bulk formation. Furthermore we observed a strong correlation between SV pool size and ability to perform ADBE. We also identified that inhibitory nerve terminals were more likely to utilize ADBE and had a larger SV recycling pool. Thus ADBE in hippocampal synaptic terminals is tightly coupled to stimulation frequency and is more likely to occur in terminals with large SV pools. These results implicate ADBE as a key modulator of both hippocampal neurotransmission and plasticity.
doi:10.1371/journal.pone.0038188
PMCID: PMC3366995  PMID: 22675521
18.  Influence of brain-derived neurotrophic factor and apolipoprotein E genetic variants on hemispheric and lateral ventricular volume of young healthy adults 
Objective
Brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) are thought to be implicated in a variety of neuronal processes, including cell growth, resilience to noxious stimuli and synaptic plasticity. A Val to Met substitution at codon 66 in the BDNF protein has been associated with a variety of neuropsychiatric conditions. The ApoE4 allele is considered a risk factor for late-onset Alzheimer’s disease, but its effects on young adults are less clear. We sought to investigate the effects of those two polymorphisms on hemispheric and lateral ventricular volumes of young healthy adults.
Methods
Hemispheric and lateral ventricular volumes of 144 healthy individuals, aged 19–35 years, were measured using high resolution magnetic resonance imaging and data were correlated with BDNF and ApoE genotypes.
Results
There were no correlations between BDNF or ApoE genotype and hemispheric or lateral ventricular volumes.
Conclusion
These findings indicate that it is unlikely that either the BDNF Val66Met or ApoE polymorphisms exert any significant effect on hemispheric or lateral ventricular volume. However, confounding epistatic genetic effects as well as relative insensitivity of the volumetric methods used cannot be ruled out. Further imaging analyses are warranted to better define any genetic influence of the BDNF Val6Met and ApoE polymorphism on brain structure of young healthy adults.
doi:10.1111/j.1601-5215.2011.00546.x
PMCID: PMC3119566  PMID: 21701702
apolipoprotein E; brain-derived neurotrophic factor; magnetic resonance imaging; polymorphism; volumetry
19.  The Acid Sphingomyelinase Sequence Variant p.A487V Is Not Associated With Decreased Levels of Enzymatic Activity 
JIMD Reports  2012;8:1-6.
Rare loss-of-function mutations in the sphingomyelin phosphodiesterase 1 (SMPD1) gene are known to dramatically decrease the catalytic activity of acid sphingomyelinase (ASM), resulting in an autosomal recessive lysosomal storage disorder known as Niemann-Pick disease (NPD) type A and B. In contrast to the general low frequency of those deleterious mutations, we found a relatively high frequency for the proposed type B NPD variant c.1460C>T (p.A487V) in our sample of 58 patients suffering from Major Depressive Disorder. We therefore investigated the biochemical consequences of this variant more closely. Our in vivo data derived from blood cell analyses indicated cellular ASM activity levels in the normal range. The secreted ASM activity levels in blood plasma were slightly lower, but still above those levels reported for type B NPD patients. In vitro expression studies of this ASM variant in different cell lines confirmed these results, showing cellular and secreted enzymatic activities equivalent to those of wild-type ASM and similar expression levels. Thus, we conclude that the ASM variant c.1460C>T (p.A487V) is not a rare missense mutation but an SMPD1 sequence variant that yields a protein with functional catalytic characteristics.
doi:10.1007/8904_2012_147
PMCID: PMC3565629  PMID: 23430512
20.  Functional Implications of Novel Human Acid Sphingomyelinase Splice Variants 
PLoS ONE  2012;7(4):e35467.
Background
Acid sphingomyelinase (ASM) hydrolyses sphingomyelin and generates the lipid messenger ceramide, which mediates a variety of stress-related cellular processes. The pathological effects of dysregulated ASM activity are evident in several human diseases and indicate an important functional role for ASM regulation. We investigated alternative splicing as a possible mechanism for regulating cellular ASM activity.
Methodology/Principal Findings
We identified three novel ASM splice variants in human cells, termed ASM-5, -6 and -7, which lack portions of the catalytic- and/or carboxy-terminal domains in comparison to full-length ASM-1. Differential expression patterns in primary blood cells indicated that ASM splicing might be subject to regulatory processes. The newly identified ASM splice variants were catalytically inactive in biochemical in vitro assays, but they decreased the relative cellular ceramide content in overexpression studies and exerted a dominant-negative effect on ASM activity in physiological cell models.
Conclusions/Significance
These findings indicate that alternative splicing of ASM is of functional significance for the cellular stress response, possibly representing a mechanism for maintaining constant levels of cellular ASM enzyme activity.
doi:10.1371/journal.pone.0035467
PMCID: PMC3338701  PMID: 22558155
21.  Optimized data preprocessing for multivariate analysis applied to 99mTc-ECD SPECT data sets of Alzheimer's patients and asymptomatic controls 
Multivariate image analysis has shown potential for classification between Alzheimer's disease (AD) patients and healthy controls with a high-diagnostic performance. As image analysis of positron emission tomography (PET) and single photon emission computed tomography (SPECT) data critically depends on appropriate data preprocessing, the focus of this work is to investigate the impact of data preprocessing on the outcome of the analysis, and to identify an optimal data preprocessing method. In this work, technetium-99methylcysteinatedimer (99mTc-ECD) SPECT data sets of 28 AD patients and 28 asymptomatic controls were used for the analysis. For a series of different data preprocessing methods, which includes methods for spatial normalization, smoothing, and intensity normalization, multivariate image analysis based on principal component analysis (PCA) and Fisher discriminant analysis (FDA) was applied. Bootstrap resampling was used to investigate the robustness of the analysis and the classification accuracy, depending on the data preprocessing method. Depending on the combination of preprocessing methods, significant differences regarding the classification accuracy were observed. For 99mTc-ECD SPECT data, the optimal data preprocessing method in terms of robustness and classification accuracy is based on affine registration, smoothing with a Gaussian of 12 mm full width half maximum, and intensity normalization based on the 25% brightest voxels within the whole-brain region.
doi:10.1038/jcbfm.2010.112
PMCID: PMC3049460  PMID: 20628401
Alzheimer's disease (AD); intensity normalization; multivariate analysis; principal component analysis (PCA); single photon emission computed tomography (SPECT); spatial normalization
22.  Non-pharmacological, multicomponent group therapy in patients with degenerative dementia: a 12-month randomzied, controlled trial 
BMC Medicine  2011;9:129.
Background
Currently available pharmacological and non-pharmacological treatments have shown only modest effects in slowing the progression of dementia. Our objective was to assess the impact of a long-term non-pharmacological group intervention on cognitive function in dementia patients and on their ability to carry out activities of daily living compared to a control group receiving the usual care.
Methods
A randomized, controlled, single-blind longitudinal trial was conducted with 98 patients (follow-up: n = 61) with primary degenerative dementia in five nursing homes in Bavaria, Germany. The highly standardized intervention consisted of motor stimulation, practice in activities of daily living, and cognitive stimulation (acronym MAKS). It was conducted in groups of ten patients led by two therapists for 2 hours, 6 days a week for 12 months. Control patients received treatment as usual. Cognitive function was assessed using the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog), and the ability to carry out activities of daily living using the Erlangen Test of Activities of Daily Living (E-ADL test) at baseline and after 12 months.
Results
Of the 553 individuals screened, 119 (21.5%) were eligible and 98 (17.7%) were ultimately included in the study. At 12 months, the results of the per protocol analysis (n = 61) showed that cognitive function and the ability to carry out activities of daily living had remained stable in the intervention group but had decreased in the control patients (ADAS-Cog: adjusted mean difference: -7.7, 95% CI -14.0 to -1.4, P = 0.018, Cohen's d = 0.45; E-ADL test: adjusted mean difference: 3.6, 95% CI 0.7 to 6.4, P = 0.015, Cohen's d = 0.50). The effect sizes for the intervention were greater in the subgroup of patients (n = 50) with mild to moderate disease (ADAS-Cog: Cohen's d = 0.67; E-ADL test: Cohen's d = 0.69).
Conclusions
A highly standardized, non-pharmacological, multicomponent group intervention conducted in a nursing-home setting was able to postpone a decline in cognitive function in dementia patients and in their ability to carry out activities of daily living for at least 12 months.
Trial Registration
http://www.isrctn.com Identifier: ISRCTN87391496
doi:10.1186/1741-7015-9-129
PMCID: PMC3254071  PMID: 22133165
dementia; non-pharmacological intervention; group therapy; RCT; nursing home
23.  Qualitative prediction of blood–brain barrier permeability on a large and refined dataset 
The prediction of blood–brain barrier permeation is vitally important for the optimization of drugs targeting the central nervous system as well as for avoiding side effects of peripheral drugs. Following a previously proposed model on blood–brain barrier penetration, we calculated the cross-sectional area perpendicular to the amphiphilic axis. We obtained a high correlation between calculated and experimental cross-sectional area (r = 0.898, n = 32). Based on these results, we examined a correlation of the calculated cross-sectional area with blood–brain barrier penetration given by logBB values. We combined various literature data sets to form a large-scale logBB dataset with 362 experimental logBB values. Quantitative models were calculated using bootstrap validated multiple linear regression. Qualitative models were built by a bootstrapped random forest algorithm. Both methods found similar descriptors such as polar surface area, pKa, logP, charges and number of positive ionisable groups to be predictive for logBB. In contrast to our initial assumption, we were not able to obtain models with the cross-sectional area chosen as relevant parameter for both approaches. Comparing those two different techniques, qualitative random forest models are better suited for blood-brain barrier permeability prediction, especially when reducing the number of descriptors and using a large dataset. A random forest prediction system (ntrees = 5) based on only four descriptors yields a validated accuracy of 88%.
Electronic supplementary material
The online version of this article (doi:10.1007/s10822-011-9478-1) contains supplementary material, which is available to authorized users.
doi:10.1007/s10822-011-9478-1
PMCID: PMC3241963  PMID: 22109848
Blood–brain barrier; Central nervous system; Membrane permeability; QSAR; LogBB; Random forest
24.  Common variants in ABCA7, MS4A6A/MS4A4E, EPHA1, CD33 and CD2AP are associated with Alzheimer’s disease 
Hollingworth, Paul | Harold, Denise | Sims, Rebecca | Gerrish, Amy | Lambert, Jean-Charles | Carrasquillo, Minerva M | Abraham, Richard | Hamshere, Marian L | Pahwa, Jaspreet Singh | Moskvina, Valentina | Dowzell, Kimberley | Jones, Nicola | Stretton, Alexandra | Thomas, Charlene | Richards, Alex | Ivanov, Dobril | Widdowson, Caroline | Chapman, Jade | Lovestone, Simon | Powell, John | Proitsi, Petroula | Lupton, Michelle K | Brayne, Carol | Rubinsztein, David C | Gill, Michael | Lawlor, Brian | Lynch, Aoibhinn | Brown, Kristelle S | Passmore, Peter A | Craig, David | McGuinness, Bernadette | Todd, Stephen | Holmes, Clive | Mann, David | Smith, A David | Beaumont, Helen | Warden, Donald | Wilcock, Gordon | Love, Seth | Kehoe, Patrick G | Hooper, Nigel M | Vardy, Emma R. L. C. | Hardy, John | Mead, Simon | Fox, Nick C | Rossor, Martin | Collinge, John | Maier, Wolfgang | Jessen, Frank | Schürmann, Britta | Rüther, Eckart | Heun, Reiner | Kölsch, Heike | van den Bussche, Hendrik | Heuser, Isabella | Kornhuber, Johannes | Wiltfang, Jens | Dichgans, Martin | Frölich, Lutz | Hampel, Harald | Hüll, Michael | Gallacher, John | Rujescu, Dan | Giegling, Ina | Goate, Alison M | Kauwe, John S K | Cruchaga, Carlos | Nowotny, Petra | Morris, John C | Mayo, Kevin | Sleegers, Kristel | Bettens, Karolien | Engelborghs, Sebastiaan | De Deyn, Peter P | Van Broeckhoven, Christine | Livingston, Gill | Bass, Nicholas J | Gurling, Hugh | McQuillin, Andrew | Gwilliam, Rhian | Deloukas, Panagiotis | Al-Chalabi, Ammar | Shaw, Christopher E | Tsolaki, Magda | Singleton, Andrew B | Guerreiro, Rita | Mühleisen, Thomas W | Nöthen, Markus M | Moebus, Susanne | Jöckel, Karl-Heinz | Klopp, Norman | Wichmann, H-Erich | Pankratz, V Shane | Sando, Sigrid B | Aasly, Jan O | Barcikowska, Maria | Wszolek, Zbigniew K | Dickson, Dennis W | Graff-Radford, Neill R | Petersen, Ronald C | van Duijn, Cornelia M | Breteler, Monique MB | Ikram, M Arfan | DeStefano, Anita L | Fitzpatrick, Annette L | Lopez, Oscar | Launer, Lenore J | Seshadri, Sudha | Berr, Claudine | Campion, Dominique | Epelbaum, Jacques | Dartigues, Jean-François | Tzourio, Christophe | Alpérovitch, Annick | Lathrop, Mark | Feulner, Thomas M | Friedrich, Patricia | Riehle, Caterina | Krawczak, Michael | Schreiber, Stefan | Mayhaus, Manuel | Nicolhaus, S | Wagenpfeil, Stefan | Steinberg, Stacy | Stefansson, Hreinn | Stefansson, Kari | Snædal, Jon | Björnsson, Sigurbjörn | Jonsson, Palmi V. | Chouraki, Vincent | Genier-Boley, Benjamin | Hiltunen, Mikko | Soininen, Hilkka | Combarros, Onofre | Zelenika, Diana | Delepine, Marc | Bullido, Maria J | Pasquier, Florence | Mateo, Ignacio | Frank-Garcia, Ana | Porcellini, Elisa | Hanon, Olivier | Coto, Eliecer | Alvarez, Victoria | Bosco, Paolo | Siciliano, Gabriele | Mancuso, Michelangelo | Panza, Francesco | Solfrizzi, Vincenzo | Nacmias, Benedetta | Sorbi, Sandro | Bossù, Paola | Piccardi, Paola | Arosio, Beatrice | Annoni, Giorgio | Seripa, Davide | Pilotto, Alberto | Scarpini, Elio | Galimberti, Daniela | Brice, Alexis | Hannequin, Didier | Licastro, Federico | Jones, Lesley | Holmans, Peter A | Jonsson, Thorlakur | Riemenschneider, Matthias | Morgan, Kevin | Younkin, Steven G | Owen, Michael J | O’Donovan, Michael | Amouyel, Philippe | Williams, Julie
Nature genetics  2011;43(5):429-435.
We sought to identify new susceptibility loci for Alzheimer’s disease (AD) through a staged association study (GERAD+) and by testing suggestive loci reported by the Alzheimer’s Disease Genetic Consortium (ADGC). First, we undertook a combined analysis of four genome-wide association datasets (Stage 1) and identified 10 novel variants with P≤1×10−5. These were tested for association in an independent sample (Stage 2). Three SNPs at two loci replicated and showed evidence for association in a further sample (Stage 3). Meta-analyses of all data provide compelling evidence that ABCA7 (meta-P 4.5×10−17; including ADGC meta-P=5.0×10−21) and the MS4A gene cluster (rs610932, meta-P=1.8×10−14; including ADGC meta-P=1.2×10−16; rs670139, meta-P=1.4×10−9; including ADGC meta-P=1.1×10−10) are novel susceptibility loci for AD. Second, we observed independent evidence for association for three suggestive loci reported by the ADGC GWAS, which when combined shows genome-wide significance: CD2AP (GERAD+ P=8.0×10−4; including ADGC meta-P=8.6×10−9), CD33 (GERAD+ P=2.2×10−4; including ADGC meta-P=1.6×10−9) and EPHA1 (GERAD+ P=3.4×10−4; including ADGC meta-P=6.0×10−10). These findings support five novel susceptibility genes for AD.
doi:10.1038/ng.803
PMCID: PMC3084173  PMID: 21460840
25.  Identification of Novel Functional Inhibitors of Acid Sphingomyelinase 
PLoS ONE  2011;6(8):e23852.
We describe a hitherto unknown feature for 27 small drug-like molecules, namely functional inhibition of acid sphingomyelinase (ASM). These entities named FIASMAs (Functional Inhibitors of Acid SphingoMyelinAse), therefore, can be potentially used to treat diseases associated with enhanced activity of ASM, such as Alzheimer's disease, major depression, radiation- and chemotherapy-induced apoptosis and endotoxic shock syndrome. Residual activity of ASM measured in the presence of 10 µM drug concentration shows a bimodal distribution; thus the tested drugs can be classified into two groups with lower and higher inhibitory activity. All FIASMAs share distinct physicochemical properties in showing lipophilic and weakly basic properties. Hierarchical clustering of Tanimoto coefficients revealed that FIASMAs occur among drugs of various chemical scaffolds. Moreover, FIASMAs more frequently violate Lipinski's Rule-of-Five than compounds without effect on ASM. Inhibition of ASM appears to be associated with good permeability across the blood-brain barrier. In the present investigation, we developed a novel structure-property-activity relationship by using a random forest-based binary classification learner. Virtual screening revealed that only six out of 768 (0.78%) compounds of natural products functionally inhibit ASM, whereas this inhibitory activity occurs in 135 out of 2028 (6.66%) drugs licensed for medical use in humans.
doi:10.1371/journal.pone.0023852
PMCID: PMC3166082  PMID: 21909365

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