Intracortical diffusion tensor imaging signature of microstructural changes in frontotemporal lobar degeneration

BACKGROUND

Frontotemporal lobar degeneration (FTLD) is a neuropathological construct with multiple clinical presentations, including the behavioural variant of frontotemporal dementia (bvFTD), primary progressive aphasia-both non-fluent variant (nfvPPA) and semantic variant (svPPA)-progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS), characterised by the deposition of abnormal tau protein in the brain. A major challenge for treating FTLD is early diagnosis and accurate discrimination among different syndromes. The main goal here was to investigate the cortical architecture of FTLD syndromes using cortical diffusion tensor imaging (DTI) analysis and to test its power to discriminate between different clinical presentations.

METHODS

A total of 271 individuals were included in the study: 87 healthy subjects (HS), 31 semantic variant primary progressive aphasia (svPPA), 37 behavioural variant (bvFTD), 30 non-fluent/agrammatic variant primary progressive aphasia (nfvPPA), 47 PSP Richardson's syndrome (PSP-RS) and 39 CBS cases. 3T MRI T1-weighted images and DTI scans were analysed to extract three cortical DTI derived measures (AngleR, PerpPD and ParlPD) and mean diffusivity (MD), as well as standard volumetric measurements. Whole brain and regional data were extracted. Linear discriminant analysis was used to assess the group discrimination capability of volumetric and DTI measures to differentiate the FTLD syndromes. In addition, in order to further investigate differential diagnosis in CBS and PSP-RS, a subgroup of subjects with autopsy confirmation in the training cohort was used to select features which were then tested in the test cohort. Three different challenges were explored: a binary classification (controls vs all patients), a multiclass classification (HS vs bvFTD vs svPPA vs nfvPPA vs CBS vs PSP-RS) and an additional binary classification to differentiate CBS and PSP-RS using features selected in an autopsy confirmed subcohort.

RESULTS

Linear discriminant analysis revealed that PerpPD was the best feature to distinguish between controls and all patients (ACC 86%). PerpPD regional values were able to classify correctly the different FTLD syndromes with an accuracy of 85.6%. The PerpPD and volumetric values selected to differentiate CBS and PSP-RS patients showed a classification accuracy of 85.2%.

CONCLUSIONS

(I) PerpPD achieved the highest classification power for differentiating healthy controls and FTLD syndromes and FTLD syndromes among themselves. (II) PerpPD regional values could provide an additional marker to differentiate FTD, PSP-RS and CBS.

Autism BrainNet: A network of postmortem brain banks established to facilitate autism research

Autism spectrum disorder (ASD or autism) is a neurodevelopmental condition that affects over 1% of the population worldwide. Developing effective preventions and treatments for autism will depend on understanding the genetic perturbations and underlying neuropathology of the disorder. While evidence from magnetic resonance imaging and other noninvasive techniques points to altered development and organization of the autistic brain, these tools lack the resolution for identifying the cellular and molecular underpinnings of the disorder. Postmortem studies of high-quality human brain tissue currently represent the only viable option to pursuing these types of studies. However, the availability of high-quality ASD brain tissue has been extremely limited. Here we describe the establishment of a privately funded tissue bank, Autism BrainNet, a network of brain collection sites that work in a coordinated fashion to develop an adequate library of human postmortem brain tissues. Autism BrainNet was initiated as a collaboration between the Simons Foundation and Autism Speaks, and is currently funded by the Simons Foundation Autism Research Initiative. Autism BrainNet has collection sites (nodes) in California, Texas, New York, and Massachusetts; an affiliated, international node is located in Oxford, England. All donations to this network become part of a consolidated pool of tissue that is distributed to qualified investigators worldwide to carry out autism research. An essential component of this program is a widespread outreach program that highlights the need for postmortem brain donations to families affected by autism, led by the Autism Science Foundation. Challenges include an outreach campaign that deals with a disorder beginning in early childhood, collecting an adequate number of donations to deal with the high level of biologic heterogeneity of autism, and preparing this limited resource for optimal distribution to the greatest number of investigators.

Cerebral amyloid angiopathy, subcortical white matter disease and dementia: literature review and study in OPTIMA

Cerebral amyloid angiopathy (CAA) is of increasing clinical and research interest as the ability to detect it and its consequences by neuroimaging in living subjects has advanced. There is also increasing interest in understanding its possible role in the development of intracerebral hemorrhage, Alzheimer's disease (AD) and vascular dementia. In this article, the literature on this subject is reviewed and novel findings relating CAA to subcortical white matter damage in 224 subjects in the Oxford project to Investigate Memory and Ageing (OPTIMA) are reported. The relationship between CAA and subcortical tissue damage in the OPTIMA subjects was found to be critically dependent on ApoE genotype, there being a positive relationship between measures of CAA and subcortical small vessel disease in ApoEε4 carriers and a significant negative relationship in ApoEε2 carriers. These findings draw attention, as have many other studies, to the importance of ApoE genotype as a major risk factor not only for dementia but also for damage to blood vessels in the aging brain.

Risk factors for suicide attempts among African American women

The aim of this study was to examine psychological and interpersonal risk factors for suicidal behavior in low income, African American women; 285 African American women who reported being in a relationship with a partner in the past year were studied, 148 presented to the hospital following a suicide attempt, and 137 presented for general medical care. Cases were compared to controls with respect to psychological symptoms, alcohol and drug abuse, family violence (intimate partner abuse, childhood trauma), relationship discord, and social support. Psychological risk factors for suicide attempts at the univariate level included psychological distress [Crude Odds Ratio (COR) = 6.5], post traumatic stress disorder (PTSD) symptoms (COR = 3.8), hopelessness (COR = 7.7), and drug abuse (COR = 4.2). Interpersonal risk factors at the univariate level included relationship discord (COR = 4.0), physical partner abuse (COR = 2.5), nonphysical partner abuse (COR = 2.8), childhood maltreatment (COR = 3.2), and low levels of social support (COR = 2.6). A multivariate logistic regression model identified four variables that were strongly and independently associated with an increased risk for suicide attempts: psychological distress, hopelessness, drug abuse, and relationship discord. The model predicted suicide attempt status correctly 77% of the time. The results reveal that African American women who report high levels of psychological distress, hopelessness, drug use, and relationship discord should be assessed carefully for suicidal ideation and referred for appropriate mental health care.

Impact of antibody specificity and calibration material on the measure of agreement between methods for cardiac troponin I

BACKGROUND

Available assays for cardiac troponin I (cTnI) yield numerically different results. The aim of this study was to compare patient values obtained from four cTnI immunoassays.

METHODS

We studied the Stratus(R) II assay, the Opus(R) II assay, the Access(R) assay, and a research-only cTnI heterogeneous immunoassay that uses the Dade Behring aca(R) plus immunoassay system equipped with two new noncommercial monoclonal antibodies. Because the aca plus cTnI assay is for research only, we first evaluated and analytically validated it for serum and citrated plasma. Initially, each method was calibrated using the method-specific calibrator supplied by each manufacturer; however, the aca plus cTnI assay was calibrated using patient serum pools containing cTnI and selected on the basis of increased creatine kinase MB isoenzyme and with values assigned by use of the Stratus cTnI assay. For method comparisons, individual patient sample cTnI values were determined and compared with the Stratus II assay.

RESULTS

Passing and Bablock regression analysis yielded slopes of 1.44 (r = 0.96; n = 72) for the Opus II vs Stratus II assays; 0.07 (r = 0.91; n = 72) for the Access vs Stratus II assays; and 0.90 (r = 0.91, n = 72) for the aca plus vs Stratus II assays. The recalibration of each method with a Stratus II-assigned serum pool improved, but did not entirely eliminate, the slope differences between the different assays (range, 1.00-1.16). The observed scatter in the correlation curves remained.

CONCLUSION

There is a need to further explore the specificities of these assays with respect to the different circulating forms of cTnI.

Factors that mediate and moderate the link between partner abuse and suicidal behavior in African American women

Findings from a study comparing partner abuse in African American women suicide attempters (n = 148) and nonattempters (n = 137) revealed higher rates of physical and nonphysical partner abuse among attempters than their demographically similar nonsuicidal counterparts. The partner abuse--suicidal behavior link was mediated by psychological distress, hopelessness, and drug use and moderated by social support. Results also revealed that nonphysical partner abuse accounted for unique variance in the prediction of suicide attempt status beyond that attributable to childhood maltreatment. Implications of the findings for assessing both suicidal and abused women are discussed, and recommendations for preventive interventions for women at risk for suicidal behavior are provided.

Factors that mediate and moderate the link between partner abuse and suicidal behavior in African American women

Findings from a study comparing partner abuse in African American women suicide attempters (n = 148) and nonattempters (n = 137) revealed higher rates of physical and nonphysical partner abuse among attempters than their demographically similar nonsuicidal counterparts. The partner abuse--suicidal behavior link was mediated by psychological distress, hopelessness, and drug use and moderated by social support. Results also revealed that nonphysical partner abuse accounted for unique variance in the prediction of suicide attempt status beyond that attributable to childhood maltreatment. Implications of the findings for assessing both suicidal and abused women are discussed, and recommendations for preventive interventions for women at risk for suicidal behavior are provided.

Computerized drug-use evaluation

A drug-use evaluation (DUE) of angiotensin-converting-enzyme (ACE) inhibitors by both manual and computerized methods was conducted. Criteria for the use of ACE inhibitors were developed and approved. Fifty patients were randomly selected from 225 clinic outpatients who had begun taking an ACE inhibitor during a six-month period. The clinic medical records of each of the patients were reviewed by a pharmacist to determine compliance with the DUE criteria. At the same time, a computer program queried the computerized medical records of the same patients to evaluate adherence to the criteria. The manual method showed that ACE inhibitor therapy met threshold for two of the six criteria before exceptions were considered and for three criteria after exceptions were considered. Results for only two criteria met threshold when evaluated by the computer; the computer did not consider exceptions. There was good or excellent percent agreement between the manual and computerized methods for four of the six criteria. Kappa values showed that the agreement for five criteria was significant. A computerized method of evaluating drug use performed similarly to manual evaluation, but agreement was best for simply stated criteria.

Interleukin 3 and cell cycle progression

Interleukin 3 (IL-3) is a regulatory glycoprotein required for the proliferation and differentiation of cells from many if not all hemopoietic lineages. With the emergence of the competence-progression model of cell proliferation, which predicts that growth factors function at specific stages of the cell cycle, we examined the possibility that IL-3 functions at a specific stage of the cell cycle. C-63 cells were developed as a cell line from normal murine bone marrow. They have a mast cell phenotype and require pokeweed-stimulated spleen cell-conditioned medium (CM), a rich source of IL-3, for their continued growth. Exponentially growing cells were transferred from growth medium, which contains CM, to medium lacking CM or IL-3. After 24 hours, cell viability had decreased 40-50%. The remaining viable cells did not incorporate 3H-thymidine, and displayed a single peak at G1 in a DNA histogram. Restimulation of these cells with CM or IL-3 resulted in a dramatic rise in 3H-thymidine uptake 20-24 hours after restimulation. DNA histograms of restimulated cultures indicated that the cells were progressing in a wave-like fashion throughout the remainder of the cell cycle. The length of time necessary for cells to be in contact with CM or IL-3 before they could progress into the remainder of the cell cycle was also examined. Cells incubated with CM or IL-3 for less than 16 hours could not progress into S phase, whereas cells incubated for 16 hours or longer could progress into S phase and through the remainder of the cell cycle. These data suggest that IL-3 exerts its function at a specific stage of the cell cycle.