3,380 research outputs found
Structural equation modeling and principal component analysis of gray matter volumes in major depressive and bipolar disorders: differences in latent volumetric structure
No full textAbnormalities of the cortico-striatal-thalamic-cortical (CSTC) and the limbic-cortico-striatal-thalamic-cortical (LCSTC) circuits have been hypothesized in mood disorders. We performed principal component analysis (PCA) to identify latent volumetric systems on regional brain volumes and correlated these patterns with clinical characteristics; further, we performed exploratory structural equation modeling (SEM) to test a priori hypotheses about the organization among the structures comprising the CSTC and LCSTC circuits, and to investigate differences among subjects with bipolar disorder (BD), major depressive disorder (MDD), and healthy controls (HC). Participants included 45 BD and 31 MDD patients, and 72 HC. Regional MR brain volumes were used to calculate patterns of volumetric covariance. The identified latent volumetric systems were related to the depression severity and the duration of illness. BD differed from HC on the estimated parameters describing the paths of cortico-striatal, thalamo-striatal and intrastriatal loops of the CSTC circuit, and the paths between anterior and posterior cingulate cortex (PCC), and hippocampus to amygdala of the LCSTC circuit. MDD differed from HC on the paths between putamen and thalamus, and PCC to hippocampus. This study provides evidence to suggest different organizational patterns among structures within the CSTC and LCSTC circuits for BD, MDD, and HC, which may point to structural abnormalities underlying mood disorders
MRI study of corpus callosum in patients with borderline personality disorder. A pilot study
No full textThis pilot study examined the integrity of the corpus callosum in a sample of patients with borderline personality disorder (BPD), as abnormalities in inter-hemispheric communication could possibly be involved in illness pathophysiology. We utilized magnetic resonance imaging (MRI) signal intensity (SI) and morphometric measures. Ten BPD and 20 healthy control subjects were assessed for current and past Axis I and Axis II comorbidities and histories of childhood abuse. Regional CC SI and areas were measured with semi-automated software from three-dimensional gradient echo imaging scans. Analysis of covariance was conducted to evaluate the results. No significant differences were observed between BPD and controls in the SI or area of any CC region. Abnormalities in interhemispheric connectivity do not appear necessary for the development of BPD. Further studies with larger samples are needed to confirm this preliminary finding
Draft toxicological profile for JP-5, JP-8, and jet A fuels
Get PDFA Toxicological Profile for JP-5 and JP-8 was released in 1998. This present edition supersedes any previously released draft or final profile.Chemical manager(s)/author(s): John Risher, Obaid Faroon, ATSDR, Division of Toxicology and Human Health Sciences, Atlanta, GA; Fernando Llados, Lisa Ingerman, Mario Citra, SRC, Inc., North Syracuse, NY
Shock tube study of JP-10 ignition delay time
No full textJP-10 (exo-tetrahydrodicyclopentadiene, C10H16) ignition delay times were measured in a preheated shock tube. The vapor pressures of the JP-10 were measured directly by using a high-precision vacuum gauge, to remedy the difficulty in determining the gaseous concentrations of heavy hydrocarbon fuel arising from the adsorption on the wall in shock tube experiments. The whole variation of pressure and emission of the OH or CH radicals were observed in the ignition process by a pressure transducer and a photomultiplier with a monochromator. The emission of the OH or CH radicals was used to identify the time to ignition. Experiments were performed over the pressure range of 151-556 kPa, temperature range of 1000-2100 K, fuel concentrations of 0.1%-0.55% mole fraction, and stoichiometric ratios of 0.25, 0.5, 1.0 and 2.0. The experimental results show that for the lower and higher temperature ranges, there are different dependency relationships of the ignition time on the temperature and the concentrations of JP-10 and oxygen
Variation in hatch date distributions, settlement and growth of juvenile plaice (Pleuronectes platessa L.) in Icelandic waters
No full textHatch date distribution, larval phase and subsequent growth of juvenile plaice (Pleuronectes platessa L.) in different regions around Iceland were determined by otolith microstructure analysis. Length, age and hatch date frequency distributions were obtained from juveniles captured in a 1 m beam trawl on 31 stations at 0.5-1 m depth all around Iceland in July 2006. The main spawning has previously been assumed to take place on the south and south-west coasts with eggs and larvae then distributed by currents along the west and north coasts. Contrary to this expected dispersal pattern, both size and age of juvenile plaice decreased from south to north. The results indicate that the observed spatial variation in size of the juveniles is not explained by different growth rates but by age. The juveniles at the south coast hatched earlier than juveniles on the north and east coasts and had a shorter larval period. Growth differed between regions and was partially explained by temperature. The study provides evidence that the juvenile plaice population may in fact originate from multiple spawning sites located not only along the south and south-west coasts, but along the entire coast of Iceland. The findings are discussed in relation to currents and temperature in Icelandic waters
Anatomical Mri Study Of Hippocampus And Amygdala in Patients With Acute And Remitted Major Depression
No full textIllness duration and total brain gray matter in bipolar disorder: evidence for neurodegeneration?
No full textPrevious studies have suggested that bipolar disorder (BD) is associated with alterations in neuronal plasticity, but the effects of the progression of illness on brain anatomy have been poorly investigated. We studied the correlation between length of illness, age, age at onset, and the number of previous episodes and total brain, total gray, and total white matter volumes in BD, unipolar (UP) and healthy control (HC) subjects. Thirty-six BD, 31 UP and 55 HCs underwent a 1.5 T brain magnetic resonance imaging scan, and gray and white matter volumes were manually traced blinded to the subjects' diagnosis. Partial correlation analysis showed that length of illness was inversely correlated with total gray matter volume after adjusting for total intracranial volume in BD (r(p)= -0.51; p=0.003) but not in UP subjects (r(p)= -0.23; p=0.21). Age at illness onset and the number of previous episodes were not significantly correlated with gray matter volumes in BD or UP subjects. No significant correlation with total white matter volume was observed. These results suggest that the progression of illness may be associated with abnormal cellular plasticity. Prospective longitudinal studies are necessary to elucidate the long-term effects of illness progression on brain structure in major mood disorders
The subgenual prefrontal cortex of child and adolescent bipolar patients: a morphometric MRI study
No full textThe subgenual prefrontal cortex (SGPFC) plays an important role in emotional processing. We carried out a magnetic resonance imaging (MRI) study comparing the volume of the SGPFC in child and adolescent bipolar patients and healthy controls. The sample consisted of 15 children and adolescents who met DSM-IV criteria for bipolar disorder (mean age +/- S.D.=15.5 +/- 3.5 years) and 21 healthy adolescents (mean age +/- S.D.=16.9 +/- 3.8 years). MR images were obtained with a 1.5 T GE Signa Imaging System with Signa 5.4.3 software. SGPFC volumes were measured with the semi-automated software MedX (Sensor Systems, Sterling, VA, USA). ANCOVA was performed to compare SGPFC volumes between groups, using age, gender and intra-cranial volume (ICV) as covariates. The volumes (mean +/- S.D.) of the right and left SGPFC for bipolar patients were 291.27 +/- 88.70 mm(3) and 284.86 +/- 83.98 mm(3), respectively. For healthy controls, the right and left SGPFC volumes were 284.95 +/- 73.33 mm(3) and 307.55 +/- 73.67 mm(3), respectively. There were no statistically significant differences between groups regarding right or left SGPFC volumes. We found no evidence of volumetric abnormalities in the SGPFC of bipolar children and adolescents
Reduced Left Anterior Cingulate Volumes in Untreated Bipolar Patients
No full textBACKGROUND:
Functional and morphologic abnormalities of the cingulate cortex have been reported in mood disorder patients. To examine the involvement of anatomic abnormalities of the cingulate in bipolar disorder, we measured the volumes of this structure in untreated and lithium-treated bipolar patients and healthy control subjects, using magnetic resonance imaging (MRI).
METHODS:
The volumes of gray matter at the right and left anterior and posterior cingulate cortices were measured in 11 bipolar patients not taking any psychotropic medications (aged 38 +/- 11 years, 5 women), 16 bipolar patients treated with lithium monotherapy (aged 33 +/- 11 years, 7 women), and 39 healthy control subjects (aged 37 +/- 10 years, 14 women). Volumetric measurements were made with T1-weighted coronal MRI images, with 1.5-mm-thick slices, at 1.5T, and were done blindly.
RESULTS:
Using analysis of covariance with age and intracranial volume as covariates, we found that untreated bipolar patients had decreased left anterior cingulate volumes compared with healthy control subjects [2.4 +/-.3 cm3 and 2.9 +/-.6 cm3, respectively; F(1,58) = 6.4, p =.042] and compared with lithium-treated patients [3.3 +/-.5 cm3; F(1,58) = 11.7, p =.003]. The cingulate volumes in lithium-treated patients were not significantly different from those of healthy control subjects.
CONCLUSIONS:
Our findings indicate that anatomic abnormalities in left anterior cingulate are present in bipolar patients. Furthermore, our results suggest that lithium treatment might influence cingulate volumes in bipolar patients, which could possibly reflect postulated neuroprotective effects of lithium
MRI study of the cerebellum in young bipolar patients
No full textPrior studies demonstrate structural abnormalities of cerebellar vermis in adult bipolar patients. Cerebella of 16 young bipolar patients (mean age+/-S.D.=15.5+/-3.4) and 21 healthy controls (mean age+/-S.D.=16.9+/-3.8) were examined using magnetic resonance imaging. The volumes of right, left and total cerebellum, vermis, and areas of vermal regions V1 (lobules I-V), V2 (lobules VI-VII), and V3 (lobules VIII-X) were measured. Analysis of covariance, with age, gender, and intra-cranial brain volume as covariates, revealed no significant differences in cerebellum or vermis measures between patients and controls; however, there was a trend to smaller vermis V2 areas in patients (p=0.06). The number of previous affective episodes and vermis area V2 were inversely correlated (partial correlation coefficient=-0.97, P=0.001) in the male bipolar patient group. Our results are preliminary, but consistent with the findings from studies in adult bipolar patients suggesting the involvement of structural changes in cerebellar vermis in the pathophysiology of bipolar disorder
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