Automatic brain extraction methods for T1 magnetic resonance images using region labeling and morphological operations

In this work we propose two brain extraction methods (BEM) that solely depend on the brain anatomy and its intensity characteristics. Our methods are simple, unsupervised and knowledge based. Using an adaptive intensity thresholding method on the magnetic resonance images of head scans, a binary image is obtained. The binary image is labeled using the anatomical facts that the scalp is the boundary between head and background, and the skull is the boundary separating brain and scalp. A run length scheme is applied on the labeled image to get a rough brain mask. Morphological operations are then performed to obtain the fine brain on the assumption that brain is the largest connected component (LCC). But the LCC concept failed to work on some slices where brain is composed of more than one connected component. To solve this problem a 3-D approach is introduced in the BEM. Experimental results on 61 sets of T1 scans taken from MRI scan center and neuroimage web services showed that our methods give better results than the popular methods, FSL's Brain Extraction Tool (BET), BrainSuite's Brain Surface Extractor (BSE) gives results comparable to that of Model-based Level Sets (MLS) and works well even where MLS failed. The average Dice similarity index computed using the “Gold standard” and the specificity values are 0.938 and 0.992, respectively, which are higher than that for BET, BSE and MLS. The average processing time by one of our methods is ≈1 s/slice, which is smaller than for MLS, which is ≈4 s/slice. One of our methods produces the lowest false positive rate of 0.075, which is smaller than that for BSE, BET and MLS. It is independent of imaging orientation and works well for slices with abnormal features like tumor and lesion in which the existing methods fail in certain cases.     

A high-resolution large area serotonin map of a live rat brain section

We employ three-photon microscopy to produce a high-resolution map of serotonin autofluorescence in a rat midbrain section (covering more than half of the brain), to quantitatively characterize serotonin distribution and release in different areas of a live brain slice. The map consists of a tiling of approximately 160 contiguous optical images (covering an area of approximately 27 mm with sub-mum resolution in 20 min), and is recorded before and after inducing depolarization. We observe that the total serotonin exocytosed from the somata in the raphe is quantitatively comparable with regions containing a high density of serotonergic processes. Our results demonstrate that high-resolution, wide-area, dynamic neurotransmitter mapping is now possible.     

Critical analysis of outcome measures used in the assessment of carpal tunnel syndrome

Clinicians and researchers are confounded by the various outcome measures used for the assessment of carpal tunnel syndrome (CTS). In this study, we critically analysed the conceptual framework, validity, reliability, responsiveness and appropriateness of some of the commonly used CTS outcome measures. Initially, we conducted an extensive literature search to identify all of the outcome measures used in the assessment of CTS patients, which revealed six different carpal tunnel outcome measures [Boston Carpal Tunnel Questionnaire (BCTQ), Michigan Hand Outcome Questionnaire (MHQ), Disability of Arm, Shoulder and Hand (DASH), Patient Evaluation Measure (PEM), clinical rating scale (Historical-Objective (Hi-Ob) scale) and Upper Extremity Functional Scale (UEFS)]. We analysed the construction framework, development process, validation process, reliability, internal consistency (IC), responsiveness and limitations of each of these outcome measures. Our analysis reveals that BCTQ, MHQ and PEM have comprehensive frameworks, good validity, reliability and responsiveness both in the hands of the developers, as well as independent researchers. The UEFS and Hi-Ob scale need validation and reliability testing by independent researchers. Region-specific measures like DASH have good frameworks and, hence, a potential role in the assessment of CTS but they require more validation in exclusive carpal tunnel patients.     

Locations of bone tissue at high risk of initial failure during compressive loading of the human vertebral body

Knowledge of the location of initial regions of failure within the vertebra - cortical shell, cortical endplates vs. trabecular bone, as well as anatomic location--may lead to improved understanding of the mechanisms of aging, disease and treatment. The overall objective of this study was to identify the location of the bone tissue at highest risk of initial failure within the vertebral body when subjected to compressive loading. Toward this end, micro-CT-based 60-micron voxel-sized, linearly elastic, finite element models of a cohort of thirteen elderly (age range: 54-87 years, 75+/-9 years) female whole vertebrae without posterior elements were virtually loaded in compression through a simulated disc. All bone tissues within each vertebra having either the maximum or minimum principal strain beyond its 90th percentile were defined as the tissue at highest risk of initial failure within that particular vertebral body. Our results showed that such high-risk tissue first occurred in the trabecular bone and that the largest proportion of the high-risk tissue also occurred in the trabecular bone. The amount of high-risk tissue was significantly greater in and adjacent to the cortical endplates than in the mid-transverse region. The amount of high-risk tissue in the cortical endplates was comparable to or greater than that in the cortical shell regardless of the assumed Poisson's ratio of the simulated disc. Our results provide new insight into the micromechanics of failure of trabecular and cortical bone within the human vertebra, and taken together, suggest that, during strenuous compressive loading of the vertebra, the tissue near and including the endplates is at the highest risk of initial failure.     

A brake becomes an accelerator: PTP1B--a new therapeutic target for breast cancer

The protein tyrosine phosphatase PTP1B, previously recognized for its role in downregulating insulin and leptin signaling, has now been shown to function as a positive regulator of signaling events associated with breast tumorigenesis. Inhibitors of PTP1B that have been developed as drug candidates for treatment of diabetes and obesity may offer new avenues for the treatment of breast cancer.     

Native pentameric C-reactive protein displays more potent pro-atherogenic activities in human aortic endothelial cells than modified C-reactive protein

Inflammation is pivotal in atherogenesis. Numerous prospective studies have shown that levels of high sensitive C-reactive protein (CRP) predict cardiovascular events. Recently, data suggests that CRP could be a mediator in atherothrombosis. Loss of pentameric symmetry in CRP has been shown to result in the formation of modified CRP (mCRP). The main aim of this study was to examine the biological effects of the native, pentameric form of CRP compared to a modified form in human aortic endothelial cells. Human pentameric native CRP (n-CRP) from two different sources (recombinant and serum) was purified and used. It was then subjected to EDTA chelation and urea treatment to prepare modified CRP (m-CRP). Purity of both n-CRP and m-CRP preparations was checked by gel electrophoresis. Both n-CRP and m-CRP were incubated with human aortic endothelial cells (HAEC) and biological activities was tested by assaying for interleukin-8 (IL-8), plasminogen activator inhibitor-1(PAI-1), cyclic GMP and prostaglandin F1-alpha. n-CRP significantly upregulated IL-8 at concentrations > or = 10 microg/mL while m-CRP upregulated IL-8 only at concentrations of 50 microg/mL (p < 0.05). PAI-1 levels were significantly increased to a greater extent with native compared to m-CRP (p < 0.05). While both decreased PGF1-alpha at concentrations of 50 microg/mL, the effect of native CRP was more pronounced and was evident at 10 microg/mL (p < 0.05). The most pronounced difference was observed with regard to inhibition of eNOS activity as assessed by cGMP which was observed at 10 microg/ml of native CRP but only at 50 microg/mL for m-CRP (native CRP versus mCRP: p < 0.001). Thus, native pentameric CRP compared to modified CRP exerts more potent atherogenic effects in human aortic endothelial cells.