Multimodality approach to classifying hand utilization for the clinical breast examination.

The clinical breast examination (CBE) is performed to detect breast pathology. However, little is known regarding clinical technique and how it relates to diagnostic accuracy. We sought to quantify breast examination search patterns and hand utilization with a new data collection and analysis system. Participants performed the CBE while the sensor mapping and video camera system collected performance data. From this data, algorithms were developed that measured the number of hands used during the exam and active examination time. This system is a feasible and reliable method to collect new information on CBE techniques.

Sensor-based assessment of cast placement and removal.

Appropriate pressure during the application of a cast is critical to provide adequate stabilization of fractures. Force-sensing resistors (FSR) were used to measure pressure during cast placement and removal. The data demonstrated a signature pattern of skin pressure during the different steps of cast placement and removal. This reproducible signal provides validity evidence for our model.

Human neural stem cell grafts modify microglial response and enhance axonal sprouting in neonatal hypoxic-ischemic brain injury.

BACKGROUND AND PURPOSE: Hypoxic-ischemic (HI) brain injury in newborn infants represents a major cause of cerebral palsy, development delay, and epilepsy. Stem cell-based therapy has the potential to rescue and replace the ischemic tissue caused by HI and to restore function. However, the mechanisms by which stem cell transplants induce functional recovery are yet to be elucidated. In the present study, we sought to investigate the efficacy of human neural stem cells derived from human embryonic stem cells in a rat model of neonatal HI and the mechanisms enhancing brain repair. METHODS: The human neural stem cells were genetically engineered for in vivo molecular imaging and for postmortem histological tracking. Twenty-four hours after the induction of HI, animals were grafted with human neural stem cells into the forebrain. Motor behavioral tests were performed the fourth week after transplantation. We used immunocytochemistry and neuroanatomical tracing to analyze neural differentiation, axonal sprouting, and microglia response. Treatment-induced changes in gene expression were investigated by microarray and quantitative polymerase chain reaction. RESULTS: Bioluminescence imaging permitted real time longitudinal tracking of grafted human neural stem cells. HI transplanted animals significantly improved in their use of the contralateral impeded forelimb and in the Rotorod test. The grafts showed good survival, dispersion, and differentiation. We observed an increase of uniformly distributed microglia cells in the grafted side. Anterograde neuroanatomical tracing demonstrated significant contralesional sprouting. Microarray analysis revealed upregulation of genes involved in neurogenesis, gliogenesis, and neurotrophic support. CONCLUSIONS: These results suggest that human neural stem cell transplants enhance endogenous brain repair through multiple modalities in response to HI.

Functional engraftment of the medial ganglionic eminence cells in experimental stroke model.

Currently there are no effective treatments targeting residual anatomical and behavioral deficits resulting from stroke. Evidence suggests that cell transplantation therapy may enhance functional recovery after stroke through multiple mechanisms. We used a syngeneic model of neural transplantation to explore graft-host communications that enhance cellular engraftment.The medial ganglionic eminence (MGE) cells were derived from 15-day-old transgenic rat embryos carrying green fluorescent protein (GFP), a marker, to easily track the transplanted cells. Adult rats were subjected to transient intraluminal occlusion of the medial cerebral artery. Two weeks after stroke, the grafts were deposited into four sites, along the rostro-caudal axis and medially to the stroke in the penumbra zone. Control groups included vehicle and fibroblast transplants. Animals were subjected to motor behavioral tests at 4 week posttransplant survival time. Morphological analysis demonstrated that the grafted MGE cells differentiated into multiple neuronal subtypes, established synaptic contact with host cells, increased the expression of synaptic markers, and enhanced axonal reorganization in the injured area. Initial patch-clamp recording demonstrated that the MGE cells received postsynaptic currents from host cells. Behavioral analysis showed reduced motor deficits in the rotarod and elevated body swing tests. These findings suggest that graft-host interactions influence the fate of grafted neural precursors and that functional recovery could be mediated by neurotrophic support, new synaptic circuit elaboration, and enhancement of the stroke-induced neuroplasticity.

Positron emission tomography imaging of poststroke angiogenesis.

BACKGROUND AND PURPOSE: Vascular endothelial growth factor (VEGF) and VEGF receptors (VEGFRs) play important roles during neurovascular repair after stroke. In this study, we imaged VEGFR expression with positron emission tomography (PET) to noninvasively analyze poststroke angiogenesis. METHODS: Female Sprague-Dawley rats after distal middle cerebral artery occlusion surgery were subjected to weekly MRI, (18)F-FDG PET, and (64)Cu-DOTA-VEGF(121) PET scans. Several control experiments were performed to confirm the VEGFR specificity of (64)Cu-DOTA-VEGF(121) uptake in the stroke border zone. VEGFR, BrdU, lectin staining, and (125)I-VEGF(165) autoradiography on stroke brain tissue slices were performed to validate the in vivo findings. RESULTS: T2-weighed MRI correlated with the "cold spot" on (18)F-FDG PET for rats undergoing distal middle cerebral artery occlusion surgery. The (64)Cu-DOTA-VEGF(121) uptake in the stroke border zone peaked at approximately 10 days after surgery, indicating neovascularization as confirmed by histology (VEGFR-2, BrdU, and lectin staining). VEGFR specificity of (64)Cu-DOTA-VEGF(121) uptake was confirmed by significantly lower uptake of (64)Cu-DOTA-VEGF(mutant) in vivo and intense (125)I-VEGF(165) uptake ex vivo in the stroke border zone. No appreciable uptake of (64)Cu-DOTA-VEGF(121) was observed in the brain of sham-operated rats. CONCLUSIONS: For the first time to our knowledge, we successfully evaluated the VEGFR expression kinetics noninvasively in a rat stroke model. In vivo imaging of VEGFR expression could become a significant clinical tool to plan and monitor therapies aimed at improving poststroke angiogenesis.

Mouse model of focal cerebral ischemia using endothelin-1.

Intracerebral injection of the vasoconstrictor peptide, endothelin-1 (ET-1), has been used as a method to induce focal ischemia in rats. The relative technical simplicity of this model makes it attractive for use in mice. However, the effect of ET-1 on mouse brains has not been firmly established. In this study, we determined the ability of ET-1 to induce focal cerebral ischemia in four different mouse strains (CD1, C57/BL6, NOD/SCID, and FVB). In contrast to rats, intracerebral injection of ET-1 did not produce a lesion in any mouse strain tested. A combination of ET-1 injection with either CCA occlusion or N(G)-nitro-l-arginine methyl ester (l-NAME) injection produced only a small infarct and its size was strain-dependent. A triple combination of CCA occlusion with co-injection of ET-1 and l-NAME produced a lesion in all mouse strains tested, and this resulted in a significant motor deficit. However, lesion size was still relatively small and strain-dependent. This study shows that ET-1 has a much less potent effect for producing an infarct in mice than rats.

Adherent self-renewable human embryonic stem cell-derived neural stem cell line: functional engraftment in experimental stroke model.

BACKGROUND: Human embryonic stem cells (hESCs) offer a virtually unlimited source of neural cells for structural repair in neurological disorders, such as stroke. Neural cells can be derived from hESCs either by direct enrichment, or by isolating specific growth factor-responsive and expandable populations of human neural stem cells (hNSCs). Studies have indicated that the direct enrichment method generates a heterogeneous population of cells that may contain residual undifferentiated stem cells that could lead to tumor formation in vivo. METHODS/PRINCIPAL FINDINGS: We isolated an expandable and homogenous population of hNSCs (named SD56) from hESCs using a defined media supplemented with epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and leukemia inhibitory growth factor (LIF). These hNSCs grew as an adherent monolayer culture. They were fully neuralized and uniformly expressed molecular features of NSCs, including nestin, vimentin and radial glial markers. These hNSCs did not express the pluripotency markers Oct4 or Nanog, nor did they express markers for the mesoderm or endoderm lineages. The self-renewal property of the hNSCs was characterized by a predominant symmetrical mode of cell division. The SD56 hNSCs differentiated into neurons, astrocytes and oligodendrocytes throughout multiple passages in vitro, as well as after transplantation. Together, these criteria confirm the definitive NSC identity of the SD56 cell line. Importantly, they exhibited no chromosome abnormalities and did not form tumors after implantation into rat ischemic brains and into naïve nude rat brains and flanks. Furthermore, hNSCs isolated under these conditions migrated toward the ischemia-injured adult brain parenchyma and improved the independent use of the stroke-impaired forelimb two months post-transplantation. CONCLUSIONS/SIGNIFICANCE: The SD56 human neural stem cells derived under the reported conditions are stable, do not form tumors in vivo and enable functional recovery after stroke. These properties indicate that this hNSC line may offer a renewable, homogenous source of neural cells that will be valuable for basic and translational research.