40 research outputs found

    Cerebrovascular dysfunction and microcirculation rarefaction precede white matter lesions in a mouse genetic model of cerebral ischemic small vessel disease

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    Cerebral ischemic small vessel disease (SVD) is the leading cause of vascular dementia and a major contributor to stroke in humans. Dominant mutations in NOTCH3 cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a genetic archetype of cerebral ischemic SVD. Progress toward understanding the pathogenesis of this disease and developing effective therapies has been hampered by the lack of a good animal model. Here, we report the development of a mouse model for CADASIL via the introduction of a CADASIL-causing Notch3 point mutation into a large P1-derived artificial chromosome (PAC). In vivo expression of the mutated PAC transgene in the mouse reproduced the endogenous Notch3 expression pattern and main pathological features of CADASIL, including Notch3 extracellular domain aggregates and granular osmiophilic material (GOM) deposits in brain vessels, progressive white matter damage, and reduced cerebral blood flow. Mutant mice displayed attenuated myogenic responses and reduced caliber of brain arteries as well as impaired cerebrovascular autoregulation and functional hyperemia. Further, we identified a substantial reduction of white matter capillary density. These neuropathological changes occurred in the absence of either histologically detectable alterations in cerebral artery structure or blood-brain barrier breakdown. These studies provide in vivo evidence for cerebrovascular dysfunction and microcirculatory failure as key contributors to hypoperfusion and white matter damage in this genetic model of ischemic SVD

    Microstructural Evolution in Thin Films of Electronic Materials

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    Contains reports on eight research projects.National Science Foundation (Grant ECS 85-06565)U.S. Air Force - Office of Scientific Research (Contract AFOSR 85-0154)National Science Foundation-Materials Research Laboratory(Grant DMR 81-19285)National Science Foundation (Grant DMR 85-06030)International Business Machines, Inc. Faculty Development AwardMitsui Career Development AwardInternational Business Machines, Inc.Semiconductor Research Corporation (Contract 86-05-080)Joint Services Electronics Program (Contract DAAG-29-83-K-0003)Charles Stark Draper LaboratoryDefense Advanced Research Projects Agency (DARPA)Nippon Telegraph and Telephone, Inc

    Diagnosing mucopolysaccharidosis IVA

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    Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is an autosomal recessive lysosomal storage disorder resulting from a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS) activity. Diagnosis can be challenging and requires agreement of clinical, radiographic, and laboratory findings. A group of biochemical genetics laboratory directors and clinicians involved in the diagnosis of MPS IVA, convened by BioMarin Pharmaceutical Inc., met to develop recommendations for diagnosis. The following conclusions were reached. Due to the wide variation and subtleties of radiographic findings, imaging of multiple body regions is recommended. Urinary glycosaminoglycan analysis is particularly problematic for MPS IVA and it is strongly recommended to proceed to enzyme activity testing even if urine appears normal when there is clinical suspicion of MPS IVA. Enzyme activity testing of GALNS is essential in diagnosing MPS IVA. Additional analyses to confirm sample integrity and rule out MPS IVB, multiple sulfatase deficiency, and mucolipidoses types II/III are critical as part of enzyme activity testing. Leukocytes or cultured dermal fibroblasts are strongly recommended for enzyme activity testing to confirm screening results. Molecular testing may also be used to confirm the diagnosis in many patients. However, two known or probable causative mutations may not be identified in all cases of MPS IVA. A diagnostic testing algorithm is presented which attempts to streamline this complex testing process

    Epitaxial growth of non-c-oriented ferroelectric SrBi2Ta2O9 thin films on Si(100) substrates

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    Abstract. Epitaxial SrBi 2 Ta 2 O 9 (SBT) thin films with welldefined (116) orientation have been grown by pulsed laser deposition on Si(100) substrates covered with an yttriastabilized ZrO 2 (YSZ) buffer layer and an epitaxial layer of electrically conductive SrRuO 3 . Studies on the in-plane crystallographic relations between SrRuO 3 and YSZ revealed a rectangle-on-cube epitaxy with respect to the substrate. X-ray diffraction pole figure measurements revealed welldefined orientation relations, viz. SB

    Folia Biol (Praha)

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    Rat hypodactyly (hd) is an autosomal recessive mutation manifesting in homozygotes as reduction or loss of digits II and III. We mapped the hd allele to a short segment of chromosome 10, containing 16 genes. None of these genes has been shown to influence limb development yet. In situ hybridization showed no changes in several important patterning genes (Shh, Fgf8, Bmp2, 4, 7). However, we found that expression of cartilage condensation marker Sox9, and Bmp receptor Bmpr1b (acting as an upstream activator of Sox9 expression) is absent from the subepithelial mesenchyme of the digit condensations II and III. The failure of the chondrogenic condensations to extend towards the subepithelial mesenchyme may reduce the size of digit primordia and underlie the subsequent loss of phalanges and reduction of metacarpals/metatarsals in hd rats

    Domain structures and piezoelectric properties of Pb(Zr0.2Ti0.8)O-3 nanocapacitors

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    Epitaxial ferroelectric Pb(Zr(0.2)Ti(0.8))O3 (PZT) nanoislands and nanocapacitors were fabricated by stencil mask-assisted pulsed laser deposition. By x-ray diffraction reciprocal space mapping it was observed that PZT nanoislands contain mainly c-domains and residual fractions of tilted and nontilted a-domains, while extended thin films contain only c-domains and tilted a-domains. The presence of nontilted a-domains manifests clearly that the misfit strain is significantly reduced in PZT nanoislands, compared to the thin film. Some of the a-domains turned out to be switchable under an external electric field due to the strain relaxation in the PZT nanocapacitors. The piezoresponse of PZT nanocapacitors was higher than that of continuous thin-film capacitors. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3475476]open1134sciescopu
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