Anterior Cranial Base Reconstruction with a Reverse Temporalis Muscle Flap and Calvarial Bone Graft

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Seung Gee Kwon

2012-07-01

Full Text Available BackgroundCranial base defects are challenging to reconstruct without serious complications. Although free tissue transfer has been used widely and efficiently, it still has the limitation of requiring a long operation time along with the burden of microanastomosis and donor site morbidity. We propose using a reverse temporalis muscle flap and calvarial bone graft as an alternative option to a free flap for anterior cranial base reconstruction.MethodsBetween April 2009 and February 2012, cranial base reconstructions using an autologous calvarial split bone graft combined with a reverse temporalis muscle flap were performed in five patients. Medical records were retrospectively analyzed and postoperative computed tomography scans, magnetic resonance imaging, and angiography findings were examined to evaluate graft survival and flap viability.ResultsThe mean follow-up period was 11.8 months and the mean operation time for reconstruction was 8.4±3.36 hours. The defects involved the anterior cranial base, including the orbital roof and the frontal and ethmoidal sinus. All reconstructions were successful. Viable flap vascularity and bone survival were observed. There were no serious complications except for acceptable donor site depressions, which were easily corrected with minor procedures.ConclusionsThe reverse temporalis muscle flap could provide sufficient bulkiness to fill dead space and sufficient vascularity to endure infection. The calvarial bone graft provides a rigid framework, which is critical for maintaining the cranial base structure. Combined anterior cranial base reconstruction with a reverse temporalis muscle flap and calvarial bone graft could be a viable alternative to free tissue transfer.

Reduced CSF leak in complete calvarial reconstructions of microvascular decompression craniectomies using calcium phosphate cement.

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Eseonu, Chikezie I; Goodwin, C Rory; Zhou, Xin; Theodros, Debebe; Bender, Matthew T; Mathios, Dimitrios; Bettegowda, Chetan; Lim, Michael

2015-12-01

Calcium phosphate cement provides a biomaterial that can be used for calvarial reconstruction in a retrosigmoid craniectomy for microvascular decompression (MVD). This study evaluates the outcomes of postoperative CSF leak and wound infection for patients undergoing a complete cranioplasty using calcium phosphate cement versus incomplete cranioplasty using polyethylene titanium mesh following a retrosigmoid craniectomy for MVD. The authors evaluated 211 cases involving patients who underwent first-time retrosigmoid craniectomies performed by a single attending surgeon fortrigeminal neuralgia from October 2008 to June 2014. From this patient population, 111 patients underwent calvarial reconstruction after retrosigmoid craniectomy using polyethylene titanium mesh, and 100 patients had reconstructions using calcium phosphate cement. A Pearson's chi-square test was used to compare postoperative complications of CSF leak and wound infection in these 2 types of cranioplasties. The polyethylene titanium mesh group included 5 patients (4.5%) with postoperative CSF leak or pseudomeningocele and 3 patients (2.7%) with wound infections. In the calcium phosphate cement group, no patients had a CSF leak, and 2 patients (2%) had wound infections. This represented a statistically significant reduction of postoperative CSF leak in patients who underwent calcium phosphate reconstructions of their calvarial defect compared with those who underwent polyethylene titanium mesh reconstructions (p = 0.03). No significant difference was seen between the 2 groups in the number of patients with postoperative wound infections. Calcium phosphate cement provides a viable alternative biomaterial for calvarial reconstruction of retrosigmoid craniectomy defects in patients who have an MVD. The application of this material provides a biocompatible barrier that reduces the incidence of postoperative CSF leaks.

Calvarial Suture-Derived Stem Cells and Their Contribution to Cranial Bone Repair

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Daniel H. Doro

2017-11-01

Full Text Available In addition to the natural turnover during life, the bones in the skeleton possess the ability to self-repair in response to injury or disease-related bone loss. Based on studies of bone defect models, both processes are largely supported by resident stem cells. In the long bones, the source of skeletal stem cells has been widely investigated over the years, where the major stem cell population is thought to reside in the perivascular niche of the bone marrow. In contrast, we have very limited knowledge about the stem cells contributing to the repair of calvarial bones. In fact, until recently, the presence of specific stem cells in adult craniofacial bones was uncertain. These flat bones are mainly formed via intramembranous rather than endochondral ossification and thus contain minimal bone marrow space. It has been previously proposed that the overlying periosteum and underlying dura mater provide osteoprogenitors for calvarial bone repair. Nonetheless, recent studies have identified a major stem cell population within the suture mesenchyme with multiple differentiation abilities and intrinsic reparative potential. Here we provide an updated review of calvarial stem cells and potential mechanisms of regulation in the context of skull injury repair.

Dural enhancement with primary calvarial lesions.

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Arana, E; Martí-Bonmatí, L; Ricart, V; Pérez-Ebrí, M

2004-11-01

The purpose of this study was to relate the pathological and imaging features of dural enhancement and meningeal sign ("dural tail") on contrast-enhanced T1-weighted magnetic resonance (MR) images from patients with primary calvarial lesions as well to assess the accuracy of MR imaging in predicting dural invasion. Thirty-two calvarial tumors studied with contrast-enhanced MR imaging and histopathological examination of the dural specimens were reviewed. Sixteen patients presented dural enhancement, eight with tumor invasion. Tumoral invasion of the dura was observed in one case without enhancement. Malignant lesions showed enhanced dura more commonly than benign lesions (P=0.02). Nodular and discontinuous dural enhancement was statistically associated with dural invasion (P=0.05). Dural tail did not show a specific pathological association. Meningeal enhancement is a nonspecific reaction to calvarial lesions unless nodular and discontinuous. False-negative and -positive cases of dural invasion imply some limitation of contrast-enhanced MR imaging in predicting dural invasion by calvarial neoplasms.

Dural enhancement with primary calvarial lesions

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Arana, E. [Clinica Quiron, Department of Radiology, Valencia (Spain); Marti-Bonmati, L. [Clinica Quiron, Department of Radiology, Valencia (Spain); Hospital Universitario Dr. Peset, Department of Radiology, Valencia (Spain); Ricart, V. [Hospital de la Ribera, Department of Radiology, Valencia (Spain); Perez-Ebri, M. [Hospital Universitario Dr. Peset, Department of Pathology, Valencia (Spain)

2004-11-01

The purpose of this study was to relate the pathological and imaging features of dural enhancement and meningeal sign (''dural tail'') on contrast-enhanced T1-weighted magnetic resonance (MR) images from patients with primary calvarial lesions as well to assess the accuracy of MR imaging in predicting dural invasion. Thirty-two calvarial tumors studied with contrast-enhanced MR imaging and histopathological examination of the dural specimens were reviewed. Sixteen patients presented dural enhancement, eight with tumor invasion. Tumoral invasion of the dura was observed in one case without enhancement. Malignant lesions showed enhanced dura more commonly than benign lesions (P=0.02). Nodular and discontinuous dural enhancement was statistically associated with dural invasion (P=0.05). Dural tail did not show a specific pathological association. Meningeal enhancement is a nonspecific reaction to calvarial lesions unless nodular and discontinuous. False-negative and -positive cases of dural invasion imply some limitation of contrast-enhanced MR imaging in predicting dural invasion by calvarial neoplasms. (orig.)

Porous titanium scaffolds with injectable hyaluronic acid-DBM gel for bone substitution in a rat critical-sized calvarial defect model.

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van Houdt, C I A; Cardoso, D A; van Oirschot, B A J A; Ulrich, D J O; Jansen, J A; Leeuwenburgh, S C G; van den Beucken, J J J P

2017-09-01

Demineralized bone matrix (DBM) is an allograft bone substitute used for bone repair surgery to overcome drawbacks of autologous bone grafting, such as limited supply and donor-site comorbidities. In view of different demineralization treatments to obtain DBM, we examined the biological performance of two differently demineralized types of DBM, i.e. by acidic treatment using hydrochloric acid (HCl) or treatment with the chelating agent ethylene diamine tetra-acetate (EDTA). First, we evaluated the osteo-inductive properties of both DBMs by implanting the materials subcutaneously in rats. Second, we evaluated the effects on bone formation by incorporating DBM in a hyaluronic acid (HA) gel to fill a porous titanium scaffold for use in a critical-sized calvarial defect model in 36 male Wistar rats. These porous titanium scaffolds were implanted empty or filled with HA gel containing either DBM HCl or DBM EDTA. Ectopically implanted DBM HCl and DBM EDTA did not induce ectopic bone formation over the course of 12 weeks. For the calvarial defects, mean percentages of newly formed bone at 2 weeks were significantly higher for Ti-Empty compared to Ti-HA + DBM HCl , but not compared to Ti-HA + DBM EDTA. Significant temporal bone formation was observed for Ti-Empty and Ti-HA + DBM HCl, but not for Ti-HA + DBM EDTA. At 8 weeks there were no significant differences in values of bone formation between the three experimental constructs. In conclusion, these results showed that, under the current experimental conditions, neither DBM HCl nor DBM EDTA possess osteo-inductive properties. Additionally, in combination with an HA gel loaded in a porous titanium scaffold, DBM HCl and DBM EDTA showed similar amounts of new bone formation after 8 weeks, which were lower than using the empty porous titanium scaffold. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Comparison of ossification of demineralized bone, hydroxyapatite, Gelfoam, and bone wax in cranial defect repair.

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Papay, F A; Morales, L; Ahmed, O F; Neth, D; Reger, S; Zins, J

1996-09-01

Demineralized bone allografts in the repair of calvarial defects are compared with other common bone fillers. This study uses a video-digitizing radiographic analysis of calvarial defect ossification to determine calcification of bone defects and its relation to postoperative clinical examination and regional controls. The postoperative clinical results at 3 months demonstrated that bony healing was greatest in bur holes filled with demineralized bone and hydroxyapatite. Radiographic analysis demonstrated calcification of demineralized bone-filled defects compared to bone wax- and Gelfoam-filled regions. Hydroxyapatite granules are radiographically dense, thus not allowing accurate measurement of true bone healing. The results suggest that demineralized bone and hydroxyapatite provide better structural support via bone healing to defined calvarial defects than do Gelfoam and bone wax.

* Calvarial Bone Regeneration Is Enhanced by Sequential Delivery of FGF-2 and BMP-2 from Layer-by-Layer Coatings with a Biomimetic Calcium Phosphate Barrier Layer.

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Gronowicz, Gloria; Jacobs, Emily; Peng, Tao; Zhu, Li; Hurley, Marja; Kuhn, Liisa T

2017-12-01

A drug delivery coating for synthetic bone grafts has been developed to provide sequential delivery of multiple osteoinductive factors to better mimic aspects of the natural regenerative process. The coating is composed of a biomimetic calcium phosphate (bCaP) layer that is applied to a synthetic bone graft and then covered with a poly-l-Lysine/poly-l-Glutamic acid polyelectrolyte multilayer (PEM) film. Bone morphogenetic protein-2 (BMP-2) was applied before the coating process directly on the synthetic bone graft and then, bCaP-PEM was deposited followed by adsorption of fibroblast growth factor-2 (FGF-2) into the PEM layer. Cells access the FGF-2 immediately, while the bCaP-PEM temporally delays the cell access to BMP-2. In vitro studies with cells derived from mouse calvarial bones demonstrated that Sca-1 and CD-166 positive osteoblast progenitor cells proliferated in response to media dosing with FGF-2. Coated scaffolds with BMP-2 and FGF-2 were implanted in mouse calvarial bone defects and harvested at 1 and 3 weeks. After 1 week in vivo, proliferation of cells, including Sca-1+ progenitors, was observed with low dose FGF-2 and BMP-2 compared to BMP-2 alone, indicating that in vivo delivery of FGF-2 activated a similar population of cells as shown by in vitro testing. At 3 weeks, FGF-2 and BMP-2 delivery increased bone formation more than BMP-2 alone, particularly in the center of the defect, confirming that the proliferation of the Sca-1 positive osteoprogenitors by FGF-2 was associated with increased bone healing. Areas of bone mineralization were positive for double fluorochrome labeling of calcium and alkaline phosphatase staining of osteoblasts, along with increased TRAP+ osteoclasts, demonstrating active bone formation distinct from the bone-like collagen/hydroxyapatite scaffold. In conclusion, the addition of a bCaP layer to PEM delayed access to BMP-2 and allowed the FGF-2 stimulated progenitors to populate the scaffold before differentiating in

Assessment of bone healing ability of calcium phosphate cements loaded with platelet lysate in rat calvarial defects.

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Babo, Pedro S; Carvalho, Pedro P; Santo, Vítor E; Faria, Susana; Gomes, Manuela E; Reis, Rui L

2016-11-01

Injectable calcium phosphate cements have been used as a valid alternative to autologous bone grafts for bone augmentation with the additional advantage of enabling minimally invasive implantation procedures and for perfectly fitting the tissue defect. Nevertheless, they have low biodegradability and lack adequate biochemical signaling to promote bone healing and remodeling. In previous in vitro studies, we observed that the incorporation of platelet lysate directly into the cement paste or loaded in hyaluronic acid microspheres allowed to modulate the cement degradation and the in vitro expression of osteogenic markers in seeded human adipose derived stem cells. The present study aimed at investigating the possible effect of this system in new bone formation when implanted in calvarial bilateral defects in rats. Different formulations were assessed, namely plain calcium phosphate cements, calcium phosphate cements loaded with human platelet lysate, hybrid injectable formulations composed of the calcium phosphate cement incorporating hyaluronin acid non-loaded microparticles (20% hyaluronin acid) or with particles loaded with platelet lysate. The degradability and new bone regrowth were evaluated in terms of mineral volume in the defect, measured by micro-computed tomography and histomorphometric analysis upon 4, 8 and 12 weeks of implantation. We observed that the incorporation of hyaluronin acid microspheres induced an overly rapid cement degradation, impairing the osteoconductive properties of the cement composites. Moreover, the incorporation of platelet lysate induced higher bone healing than the materials without platelet lysate, up to four weeks after surgery. Nevertheless, this effect was not found to be significant when compared to the one observed in the sham-treated group. © The Author(s) 2016.

Deletion of SHP-2 in mesenchymal stem cells causes growth retardation, limb and chest deformity, and calvarial defects in mice

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Philip E. Lapinski

2013-11-01

In mice, induced global disruption of the Ptpn11 gene, which encodes the SHP-2 tyrosine phosphatase, results in severe skeletal abnormalities. To understand the extent to which skeletal abnormalities can be attributed to perturbation of SHP-2 function in bone-forming osteoblasts and chondrocytes, we generated mice in which disruption of Ptpn11 is restricted to mesenchymal stem cells (MSCs and their progeny, which include both cell types. MSC-lineage-specific SHP-2 knockout (MSC SHP-2 KO mice exhibited postnatal growth retardation, limb and chest deformity, and calvarial defects. These skeletal abnormalities were associated with an absence of mature osteoblasts and massive chondrodysplasia with a vast increase in the number of terminally differentiated hypertrophic chondrocytes in affected bones. Activation of mitogen activated protein kinases (MAPKs and protein kinase B (PKB; also known as AKT was impaired in bone-forming cells of MSC SHP-2 KO mice, which provides an explanation for the skeletal defects that developed. These findings reveal a cell-autonomous role for SHP-2 in bone-forming cells in mice in the regulation of skeletal development. The results add to our understanding of the pathophysiology of skeletal abnormalities observed in humans with germline mutations in the PTPN11 gene (e.g. Noonan syndrome and LEOPARD syndrome.

Osterix-Cre transgene causes craniofacial bone development defect

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Wang, Li; Mishina, Yuji; Liu, Fei

2015-01-01

The Cre/loxP system has been widely used to generate tissue-specific gene knockout mice. Inducible (Tet-off) Osx-GFP::Cre (Osx-Cre) mouse line that targets osteoblasts is widely used in the bone research field. In this study, we investigated the effect of Osx-Cre on craniofacial bone development. We found that newborn Osx-Cre mice showed severe hypomineralization in parietal, frontal, and nasal bones as well as the coronal sutural area when compared to control mice. As the mice matured the intramembranous bone hypomineralization phenotype became less severe. The major hypomineralization defect in parietal, frontal, and nasal bones had mostly disappeared by postnatal day 21, but the defect in sutural areas persisted. Importantly, Doxycycline treatment eliminated cranial bone defects at birth which indicates that Cre expression may be responsible for the phenotype. In addition, we showed that the primary calvarial osteoblasts isolated from neonatal Osx-Cre mice had comparable differentiation ability compared to their littermate controls. This study reinforces the idea that Cre positive litter mates are indispensable controls in studies using conditional gene deletion. PMID:25550101

Imaging pattern of calvarial lesions in adults

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Garfinkle, Jarred; Melancon, Denis; Cortes, Maria; Tampieri, Donatella [Montreal Neurological Institute and Hospital-McGill University Health Center, Department of Diagnostic and Interventional Neuroradiology, Montreal, Quebec (Canada)

2011-10-15

Calvarial lesions often present themselves as clinically silent findings on skull radiographs or as palpable masses that may cause localized pain or soreness. This review aims to explore the radiographic, computed tomography (CT), and magnetic resonance imaging (MRI) characteristics of calvarial neoplastic, inflammatory, and congenital lesions that are common in adults in order to facilitate a structured approach to their diagnosis and limit the differential diagnosis. In addition to reviewing the literature, we reviewed the records of 141 patients of the Montreal Neurological Institute and Hospital with radiologically documented calvarial lesions between 2001 and June 2009. CT is ideal for detecting bony lesions and is helpful in precisely localizing a lesion pre-surgically. MRI is best at identifying intradiploic lesions before they affect the cortical tables and is able to establish extraosseous involvement, especially when paramagnetic contrast is employed. (orig.)

Reprogramming of Mouse Calvarial Osteoblasts into Induced Pluripotent Stem Cells

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Yinxiang Wang

2018-01-01

Full Text Available Previous studies have demonstrated the ability of reprogramming endochondral bone into induced pluripotent stem (iPS cells, but whether similar phenomenon occurs in intramembranous bone remains to be determined. Here we adopted fluorescence-activated cell sorting-based strategy to isolate homogenous population of intramembranous calvarial osteoblasts from newborn transgenic mice carrying both Osx1-GFP::Cre and Oct4-EGFP transgenes. Following retroviral transduction of Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc, enriched population of osteoblasts underwent silencing of Osx1-GFP::Cre expression at early stage of reprogramming followed by late activation of Oct4-EGFP expression in the resulting iPS cells. These osteoblast-derived iPS cells exhibited gene expression profiles akin to embryonic stem cells and were pluripotent as demonstrated by their ability to form teratomas comprising tissues from all germ layers and also contribute to tail tissue in chimera embryos. These data demonstrate that iPS cells can be generated from intramembranous osteoblasts.

Enhanced Healing of Rat Calvarial Defects with MSCs Loaded on BMP-2 Releasing Chitosan/Alginate/Hydroxyapatite Scaffolds

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He, Xiaoning; Liu, Yang; Yuan, Xue; Lu, Li

2014-01-01

In this study, we designed a chitosan/alginate/hydroxyapatite scaffold as a carrier for recombinant BMP-2 (CAH/B2), and evaluated the release kinetics of BMP-2. We evaluated the effect of the CAH/B2 scaffold on the viability and differentiation of bone marrow mesenchymal stem cells (MSCs) by scanning electron microscopy, MTS, ALP assay, alizarin-red staining and qRT-PCR. Moreover, MSCs were seeded on scaffolds and used in a 8 mm rat calvarial defect model. New bone formation was assessed by radiology, hematoxylin and eosin staining 12 weeks postoperatively. We found the release kinetics of BMP-2 from the CAH/B2 scaffold were delayed compared with those from collagen gel, which is widely used for BMP-2 delivery. The BMP-2 released from the scaffold increased MSC differentiation and did not show any cytotoxicity. MSCs exhibited greater ALP activity as well as stronger calcium mineral deposition, and the bone-related markers Col1α, osteopontin, and osteocalcin were upregulated. Analysis of in vivo bone formation showed that the CAH/B2 scaffold induced more bone formation than other groups. This study demonstrates that CAH/B2 scaffolds might be useful for delivering osteogenic BMP-2 protein and present a promising bone regeneration strategy. PMID:25084008

Bone Regeneration Using a Mixture of Silicon-Substituted Coral HA and β-TCP in a Rat Calvarial Bone Defect Model

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Jiyeon Roh

2016-02-01

Full Text Available The demand of bone graft materials has been increasing. Among various origins of bone graft materials, natural coral composed of up to 99% calcium carbonate was chosen and converted into hydroxyapatite (HA; silicon was then substituted into the HA. Then, the Si-HA was mixed with β-tricalcium phosphate (TCP in the ratios 100:0 (S100T0, 70:30 (S70T30, 60:40 (S60T40, and 50:50 (S50T50. The materials were implanted for four and eight weeks in a rat calvarial bone defect model (8 mm. The MBCPTM (HA:β-TCP = 60:40, Biomatalante, Vigneux de Bretagne, France was used as a control. After euthanasia, the bone tissue was analyzed by making histological slides. From the results, S60T40 showed the fastest bone regeneration in four weeks (p < 0.05. In addition, S60T40, S50T50, and MBCPTM showed significant new bone formation in eight weeks (p < 0.05. In conclusion, Si-HA/TCP showed potential as a bone graft material.

Regulation of Calvarial Osteogenesis by Concomitant De-repression of GLI3 and Activation of IHH Targets

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Lotta K. Veistinen; Tuija Mustonen; Tuija Mustonen; Md. Rakibul Hasan; Maarit Takatalo; Yukiho Kobayashi; Yukiho Kobayashi; Dörthe A. Kesper; Andrea Vortkamp; David P. Rice; David P. Rice

2017-01-01

Loss-of-function mutations in GLI3 and IHH cause craniosynostosis and reduced osteogenesis, respectively. In this study, we show that Ihh ligand, the receptor Ptch1 and Gli transcription factors are differentially expressed in embryonic mouse calvaria osteogenic condensations. We show that in both Ihh−/− and Gli3Xt−J/Xt−J embryonic mice, the normal gene expression architecture is lost and this results in disorganized calvarial bone development. RUNX2 is a master regulatory transcription facto...

Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model

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Zhang, Haifeng; Mao, Xiyuan; Du, Zijing; Jiang, Wenbo; Han, Xiuguo; Zhao, Danyang; Han, Dong; Li, Qingfeng

2016-01-01

We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500 μm and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, β-tricalcium phosphate (β-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteopontin (OPN) and collagen type I (COL-1). Moreover, the biocompatibility, bone repairing capacity and degradation in three different bone substitute materials were estimated using a critical-size rat calvarial defect model in vivo. The defects were evaluated by micro-computed tomography and histological analysis at four and eight weeks after surgery, respectively. The results showed that each of the studied scaffolds had its own specific merits and drawbacks. Three-dimensional printed PLA/HA scaffolds possessed good biocompatibility and stimulated BMSC cell proliferation and differentiation to osteogenic cells. The outcomes in vivo revealed that 3D printed PLA/HA scaffolds had good osteogenic capability and biodegradation activity with no difference in inflammation reaction. Therefore, 3D printed PLA/HA scaffolds have potential applications in bone tissue engineering and may be used as graft substitutes in reconstructive surgery.

Regulation of Calvarial Osteogenesis by Concomitant De-repression of GLI3 and Activation of IHH Targets

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Lotta K. Veistinen

2017-12-01

Full Text Available Loss-of-function mutations in GLI3 and IHH cause craniosynostosis and reduced osteogenesis, respectively. In this study, we show that Ihh ligand, the receptor Ptch1 and Gli transcription factors are differentially expressed in embryonic mouse calvaria osteogenic condensations. We show that in both Ihh−/− and Gli3Xt−J/Xt−J embryonic mice, the normal gene expression architecture is lost and this results in disorganized calvarial bone development. RUNX2 is a master regulatory transcription factor controlling osteogenesis. In the absence of Gli3, RUNX2 isoform II and IHH are upregulated, and RUNX2 isoform I downregulated. This is consistent with the expanded and aberrant osteogenesis observed in Gli3Xt−J/Xt−J mice, and consistent with Runx2-I expression by relatively immature osteoprogenitors. Ihh−/− mice exhibited small calvarial bones and HH target genes, Ptch1 and Gli1, were absent. This indicates that IHH is the functional HH ligand, and that it is not compensated by another HH ligand. To decipher the roles and potential interaction of Gli3 and Ihh, we generated Ihh−/−;Gli3Xt−J/Xt−J compound mutant mice. Even in the absence of Ihh, Gli3 deletion was sufficient to induce aberrant precocious ossification across the developing suture, indicating that the craniosynostosis phenotype of Gli3Xt−J/Xt−J mice is not dependent on IHH ligand. Also, we found that Ihh was not required for Runx2 expression as the expression of RUNX2 target genes was unaffected by deletion of Ihh. To test whether RUNX2 has a role upstream of IHH, we performed RUNX2 siRNA knock down experiments in WT calvarial osteoblasts and explants and found that Ihh expression is suppressed. Our results show that IHH is the functional HH ligand in the embryonic mouse calvaria osteogenic condensations, where it regulates the progression of osteoblastic differentiation. As GLI3 represses the expression of Runx2-II and Ihh, and also elevates the Runx2-I expression

Regulation of Calvarial Osteogenesis by Concomitant De-repression of GLI3 and Activation of IHH Targets.

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Veistinen, Lotta K; Mustonen, Tuija; Hasan, Md Rakibul; Takatalo, Maarit; Kobayashi, Yukiho; Kesper, Dörthe A; Vortkamp, Andrea; Rice, David P

2017-01-01

Loss-of-function mutations in GLI3 and IHH cause craniosynostosis and reduced osteogenesis, respectively. In this study, we show that Ihh ligand, the receptor Ptch1 and Gli transcription factors are differentially expressed in embryonic mouse calvaria osteogenic condensations. We show that in both Ihh -/- and Gli3 Xt - J / Xt - J embryonic mice, the normal gene expression architecture is lost and this results in disorganized calvarial bone development. RUNX2 is a master regulatory transcription factor controlling osteogenesis. In the absence of Gli3 , RUNX2 isoform II and IHH are upregulated, and RUNX2 isoform I downregulated. This is consistent with the expanded and aberrant osteogenesis observed in Gli3 Xt - J / Xt - J mice, and consistent with Runx2-I expression by relatively immature osteoprogenitors. Ihh -/- mice exhibited small calvarial bones and HH target genes, Ptch1 and Gli1 , were absent. This indicates that IHH is the functional HH ligand, and that it is not compensated by another HH ligand. To decipher the roles and potential interaction of Gli3 and Ihh, we generated Ihh -/- ; Gli3 Xt - J / Xt - J compound mutant mice. Even in the absence of Ihh, Gli3 deletion was sufficient to induce aberrant precocious ossification across the developing suture, indicating that the craniosynostosis phenotype of Gli3 Xt - J / Xt - J mice is not dependent on IHH ligand. Also, we found that Ihh was not required for Runx2 expression as the expression of RUNX2 target genes was unaffected by deletion of Ihh . To test whether RUNX2 has a role upstream of IHH, we performed RUNX2 siRNA knock down experiments in WT calvarial osteoblasts and explants and found that Ihh expression is suppressed. Our results show that IHH is the functional HH ligand in the embryonic mouse calvaria osteogenic condensations, where it regulates the progression of osteoblastic differentiation. As GLI3 represses the expression of Runx2-II and Ihh , and also elevates the Runx2-I expression, and as IHH

Tyrosine kinase receptor c-ros-oncogene 1 inhibition alleviates aberrant bone formation of TWIST-1 haploinsufficient calvarial cells from Saethre-Chotzen syndrome patients.

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Camp, Esther; Anderson, Peter J; Zannettino, Andrew C W; Glackin, Carlotta A; Gronthos, Stan

2018-09-01

Saethre-Chotzen syndrome (SCS), associated with TWIST-1 mutations, is characterized by premature fusion of cranial sutures. TWIST-1 haploinsufficiency, leads to alterations in suture mesenchyme cellular gene expression patterns, resulting in aberrant osteogenesis and craniosynostosis. We analyzed the expression of the TWIST-1 target, Tyrosine kinase receptor c-ros-oncogene 1 (C-ROS-1) in TWIST-1 haploinsufficient calvarial cells derived from SCS patients and calvaria of Twist-1 del/+ mutant mice and found it to be highly expressed when compared to TWIST-1 wild-type controls. Knock-down of C-ROS-1 expression in TWIST-1 haploinsufficient calvarial cells derived from SCS patients was associated with decreased capacity for osteogenic differentiation in vitro. Furthermore, treatment of human SCS calvarial cells with the tyrosine kinase chemical inhibitor, Crizotinib, resulted in reduced C-ROS-1 activity and the osteogenic potential of human SCS calvarial cells with minor effects on cell viability or proliferation. Cultured human SCS calvarial cells treated with Crizotinib exhibited a dose-dependent decrease in alkaline phosphatase activity and mineral deposition, with an associated decrease in expression levels of Runt-related transcription factor 2 and OSTEOPONTIN, with reduced PI3K/Akt signalling in vitro. Furthermore, Crizotinib treatment resulted in reduced BMP-2 mediated bone formation potential of whole Twist-1 del/+ mutant mouse calvaria organotypic cultures. Collectively, these results suggest that C-ROS-1 promotes osteogenic differentiation of TWIST-1 haploinsufficient calvarial osteogenic progenitor cells. Furthermore, the aberrant osteogenic potential of these cells is inhibited by the reduction of C-ROS-1. Therefore, targeting C-ROS-1 with a pharmacological agent, such as Crizotinib, may serve as a novel therapeutic strategy to alleviate craniosynostosis associated with aberrant TWIST-1 function. © 2018 Wiley Periodicals, Inc.

Osteoblast CFTR inactivation reduces differentiation and osteoprotegerin expression in a mouse model of cystic fibrosis-related bone disease.

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Michael S Stalvey

Full Text Available Low bone mass and increased fracture risk are recognized complications of cystic fibrosis (CF. CF-related bone disease (CFBD is characterized by uncoupled bone turnover--impaired osteoblastic bone formation and enhanced osteoclastic bone resorption. Intestinal malabsorption, vitamin D deficiency and inflammatory cytokines contribute to CFBD. However, epidemiological investigations and animal models also support a direct causal link between inactivation of skeletal cystic fibrosis transmembrane regulator (CFTR, the gene that when mutated causes CF, and CFBD. The objective of this study was to examine the direct actions of CFTR on bone. Expression analyses revealed that CFTR mRNA and protein were expressed in murine osteoblasts, but not in osteoclasts. Functional studies were then performed to investigate the direct actions of CFTR on osteoblasts using a CFTR knockout (Cftr-/- mouse model. In the murine calvarial organ culture assay, Cftr-/- calvariae displayed significantly less bone formation and osteoblast numbers than calvariae harvested from wildtype (Cftr+/+ littermates. CFTR inactivation also reduced alkaline phosphatase expression in cultured murine calvarial osteoblasts. Although CFTR was not expressed in murine osteoclasts, significantly more osteoclasts formed in Cftr-/- compared to Cftr+/+ bone marrow cultures. Indirect regulation of osteoclastogenesis by the osteoblast through RANK/RANKL/OPG signaling was next examined. Although no difference in receptor activator of NF-κB ligand (Rankl mRNA was detected, significantly less osteoprotegerin (Opg was expressed in Cftr-/- compared to Cftr+/+ osteoblasts. Together, the Rankl:Opg ratio was significantly higher in Cftr-/- murine calvarial osteoblasts contributing to a higher osteoclastogenesis potential. The combined findings of reduced osteoblast differentiation and lower Opg expression suggested a possible defect in canonical Wnt signaling. In fact, Wnt3a and PTH-stimulated canonical Wnt

Tissue specific mutagenic and carcinogenic responses in NER defective mouse models.

NARCIS (Netherlands)

Wijnhoven, Susan W P; Hoogervorst, Esther M; Waard, Harm de; Horst, Gijsbertus T J van der; Steeg, Harry van

2007-01-01

Several mouse models with defects in genes encoding components of the nucleotide excision repair (NER) pathway have been developed. In NER two different sub-pathways are known, i.e. transcription-coupled repair (TC-NER) and global-genome repair (GG-NER). A defect in one particular NER protein can

Donor site complications in bone grafting: comparison of iliac crest, calvarial, and mandibular ramus bone.

Science.gov (United States)

Scheerlinck, Laura M E; Muradin, Marvick S M; van der Bilt, Andries; Meijer, Gert J; Koole, Ronald; Van Cann, Ellen M

2013-01-01

To compare the donor site complication rate and length of hospital stay following the harvest of bone from the iliac crest, calvarium, or mandibular ramus. Ninety-nine consecutively treated patients were included in this retrospective observational single-center study. Iliac crest bone was harvested in 55 patients, calvarial bone in 26 patients, and mandibular ramus bone in 18 patients. Harvesting of mandibular ramus bone was associated with the lowest percentages of major complications (5.6%), minor complications (22.2%), and total complications (27.8%). Harvesting of iliac crest bone was related to the highest percentages of minor complications (56.4%) and total complications (63.6%), whereas harvesting of calvarial bone induced the highest percentage of major complications (19.2%). The length of the hospital stay was significantly influenced by the choice of donor site (P = .003) and age (P = .009); young patients with the mandibular ramus as the donor site had the shortest hospital stay. Harvesting of mandibular ramus bone was associated with the lowest percentage of complications and the shortest hospital stay. When the amount of bone to be obtained is deemed sufficient, mandibular ramus bone should be the first choice for the reconstruction of maxillofacial defects.

Quantitative trait loci affecting phenotypic variation in the vacuolated lens mouse mutant, a multigenic mouse model of neural tube defects

NARCIS (Netherlands)

Korstanje, Ron; Desai, Jigar; Lazar, Gloria; King, Benjamin; Rollins, Jarod; Spurr, Melissa; Joseph, Jamie; Kadambi, Sindhuja; Li, Yang; Cherry, Allison; Matteson, Paul G.; Paigen, Beverly; Millonig, James H.

Korstanje R, Desai J, Lazar G, King B, Rollins J, Spurr M, Joseph J, Kadambi S, Li Y, Cherry A, Matteson PG, Paigen B, Millonig JH. Quantitative trait loci affecting phenotypic variation in the vacuolated lens mouse mutant, a multigenic mouse model of neural tube defects. Physiol Genomics 35:

Death due to fracture of thin calvarial bones after a fall: A forensic approach

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Georgios Sioutas

2017-06-01

Full Text Available A 45-year-old male was autopsied. He had fallen backwards from a two-stairs height to the ground and passed away. A skull fracture was detected in the left occipital area, extending up to the left side of the skull base. The patient's death occurred due to the very low thickness of the calvarial bones, which led to the aforementioned fracture, and in turn resulted in subarachnoid hemorrhage and death. The cortical thickness was measured and compared with average values at standardized points. Uniform bone thinning was confirmed rather than localized. Calvarial thinning may result from various conditions. In the present case study, however, the exact mechanism which led to the low thickness of the calvarial bones of the patient is undetermined. Death due to the susceptible structure and fracture of calvarial bones has rarely been reported throughout relevant literature.

Incomplete bone regeneration of rabbit calvarial defects using different membranes

DEFF Research Database (Denmark)

Aaboe, M; Pinholt, E M; Schou, S

1998-01-01

The present study describes the use of a degradable and a non-degradable material for guided bone regeneration. Forty rabbits were divided into 5 groups. Bicortical defects 15 mm in diameter were prepared in rabbit calvaria. A titanium microplate was placed over the defect to prevent collapse...

Multiple calvarial haemangiomas

International Nuclear Information System (INIS)

Corr, P.

2000-01-01

Calvarial haemangiomas are rare benign tumours that may be suspected by their characteristic expansile 'sunburst' appearance. It is important to recognise them as such and to make the surgeon aware of haemorrhage after biopsy or resection. Computed tomography examination confirmed expansile spiculated osteolytic lesions originating from the right occipital calvarium and a smaller lesion from the right frontal bone. The larger lesion had a 'sunburst' appearance. On MR, the morphology of the lesion was more apparent. The tumour had a heterogenous hypointense structure with spiculated bony septa on T1-weighted images and a markedly hyperintense appearance on T2-weighted images. Copyright (1999) Blackwell Science Pty Ltd

Religious Landscape and Ecological Ethics: Pilgrimage to the Lithuanian Calvaries

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Darius Liutikas

2015-07-01

Full Text Available This article deals with the ecology of pilgrimage at the Calvaries – Ways of the Cross – in Lithuania. Personal obligations to nature and respect of sacred place intermingle with devotional practices and certain rituals. Large scale arrivals at the Calvaries only occurs at certain times of year, mostly during the Indulgence Feasts. Devotional practices such as meditation on the suffering of Christ, prayers and hymns, playing musical instruments, washing one’s face at the Cedron spring are quite common during the Way. Research shows that walking the Way of the Cross doesn’t cause negative environmental, cultural and social impacts. Moreover, pilgrimage could be beneficial to local communities - providing opportunities to sell handcraft products, to meet relatives and friends. Visiting Calvaries is a religious act restrained by time: usually it takes about 3-4 hours to undertake the Stations of the Cross, about one hour to celebrate Holy Mass, and up to one hour at the market place buying religious memorabilia and other souvenirs.

Calvarial periosteal graft for second-stage cleft palate surgery: a preliminary report.

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Neiva, Cecilia; Dakpe, Stephanie; Gbaguidi, Cica; Testelin, Sylvie; Devauchelle, Bernard

2014-07-01

The objectives of cleft palate surgery are to achieve optimal outcomes regarding speech development, hearing, maxillary arch development and facial skull growth. Early two-stage cleft palate repair has been the most recent protocol of choice to achieve good maxillary arch growth without compromising speech development. Hard palate closure occurs within one year of soft palate surgery. However, in some cases the residual hard palate cleft width is larger than 15 mm at the age of two. As previously reported, integrated speech development starts around that age and it is a challenge since we know that early mobilization of the mucoperiosteum interferes with normal facial growth on the long-term. In children with large residual hard palate clefts at the age 2, we report the use of calvarial periosteal grafts to close the cleft. With a retrospective 6-year study (2006-2012) we first analyzed the outcomes regarding impermeability of hard palate closure on 45 patients who at the age of two presented a residual cleft of the hard palate larger than 15 mm and benefited from a periosteal graft. We then studied the maxillary growth in these children. In order to compare long-term results, we included 14 patients (age range: 8-20) treated between 1994 & 2006. Two analyses were conducted, the first one on dental casts from birth to the age of 6 and the other one based on lateral cephalograms following Delaire's principles and TRIDIM software. After the systematic cephalometric analysis of 14 patients, we found no evidence of retrognathia or Class 3 dental malocclusion. In the population of 45 children who benefited from calvarial periosteal grafts the rate of palate fistula was 17% vs. 10% in the overall series. Despite major advances in understanding cleft defects, the issues of timing and choice of the surgical procedure remain widely debated. In second-stage surgery for hard palate closure, using a calvarial periosteal graft could be the solution for large residual clefts

Bone marker gene expression in calvarial bones: different bone microenvironments.

Science.gov (United States)

Al-Amer, Osama

2017-12-01

In calvarial mice, mesenchymal stem cells (MSCs) differentiate into osteoprogenitor cells and then differentiate into osteoblasts that differentiate into osteocytes, which become embedded within the bone matrix. In this case, the cells participating in bone formation include MSCs, osteoprogenitor cells, osteoblasts and osteocytes. The calvariae of C57BL/KaLwRijHsD mice consist of the following five bones: two frontal bones, two parietal bones and one interparietal bone. This study aimed to analyse some bone marker genes and bone related genes to determine whether these calvarial bones have different bone microenvironments. C57BL/KaLwRijHsD calvariae were carefully excised from five male mice that were 4-6 weeks of age. Frontal, parietal, and interparietal bones were dissected to determine the bone microenvironment in calvariae. Haematoxylin and eosin staining was used to determine the morphology of different calvarial bones under microscopy. TaqMan was used to analyse the relative expression of Runx2, OC, OSX, RANK, RANKL, OPG, N-cadherin, E-cadherin, FGF2 and FGFR1 genes in different parts of the calvariae. Histological analysis demonstrated different bone marrow (BM) areas between the different parts of the calvariae. The data show that parietal bones have the smallest BM area compared to frontal and interparietal bones. TaqMan data show a significant increase in the expression level of Runx2, OC, OSX, RANKL, OPG, FGF2 and FGFR1 genes in the parietal bones compared with the frontal and interparietal bones of calvariae. This study provides evidence that different calvarial bones, frontal, parietal and interparietal, contain different bone microenvironments.

Death due to fracture of thin calvarial bones after a fall: A forensic approach.

Science.gov (United States)

Sioutas, Georgios; Karakasi, Maria-Valeria; Kapetanakis, Stylianos; Pavlidis, Pavlos

2017-06-01

A 45-year-old male was autopsied. He had fallen backwards from a two-stairs height to the ground and passed away. A skull fracture was detected in the left occipital area, extending up to the left side of the skull base. The patient's death occurred due to the very low thickness of the calvarial bones, which led to the aforementioned fracture, and in turn resulted in subarachnoid hemorrhage and death. The cortical thickness was measured and compared with average values at standardized points. Uniform bone thinning was confirmed rather than localized. Calvarial thinning may result from various conditions. In the present case study, however, the exact mechanism which led to the low thickness of the calvarial bones of the patient is undetermined. Death due to the susceptible structure and fracture of calvarial bones has rarely been reported throughout relevant literature. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

MR findings of calvarial eosinophilic granuloma

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Choi, Gi Bok; Son, Seok Hyun; Eun, Choong Ki; Park, Sung Kun; Han, Sang Suk [Pusan Paik Hospital, Inje Univ., Pusan (Korea, Republic of); Choi, Sun Seob [Donga Univ. College of Medicine, Pusan (Korea, Republic of); Kim, Seong Min [Kosin Univ. College of Medicine, Pusan (Korea, Republic of); Kim, Chang Soo [Maryknoll Hospital, Pusan (Korea, Republic of)

2001-03-01

The purpose of this study was to evaluate the MR findings of calvarial eosinophilic granuloma. We reviewed the MR imaging studies of nine patients [M:F=3:6, aged 6-35 (mean, 20.5) years] with pathologically proven eosinophilic granuloma in the calvaria. The findings were evaluated for involvement of the diploic space, changes in adjacent bone marrow, distinction of the transitional zone, pattern of bone destruction, signal intensity and contrast enhancement of the tumor, and contrast enhancement of the adjacent dura. All lesions involved the diploic space, showed no change in adjacent bone marrow, and had a distinct transitional zone. In most (8/9) cases there was asymmetric bony destruction. On T1-weighted images, signal intensities of the tumors varied, while on T2-weighted images, hyperintensity was observed in seven cases, isointensity in one, and hypointensity in one. After the administration of contrast material, enhancement was homogeneous in four cases and inhomogeneous in five. Enhancement of the adjacent dura was demonstrated in all nine cases. The characteristic MR findings of calvarial eosinophilic granuloma are variable signal intensity on T1WI, high signal intensity on T2WI, and marked contrast enhancement; in addition, there is a distinct transitional zone, asymmetrical bony destruction, and associated dural enhancement.

Ellipsoid analysis of calvarial shape.

Science.gov (United States)

Jacobsen, Petra A; Becker, Devra; Govier, Daniel P; Krantz, Steven G; Kane, Alex

2009-09-01

The purpose of this research was to develop a novel quantitative method of describing calvarial shape by using ellipsoid geometry. The pilot application of Ellipsoid Analysis was to compare calvarial form among individuals with untreated unilateral coronal synostosis, metopic synostosis, and sagittal synostosis and normal subjects. The frontal, parietal, and occipital bones of 10 preoperative patients for each of the four study groups were bilaterally segmented into six regions using three-dimensional skull reconstructions generated by ANALYZE imaging software from high-resolution computed tomography scans. Points along each segment were extracted and manipulated using a MATLAB-based program. The points were fit to the least-squares nearest ellipsoid. Relationships between the six resultant right and left frontal, parietal, and occipital ellipsoidal centroids (FR, FL, PR, PL, OR, and OL, respectively) were tested for association with a synostotic group. Results from the pilot study showed meaningful differences between length ratio, angular, and centroid distance relationships among synostotic groups. The most substantial difference was exhibited in the centroid distance PL-PR between patients with sagittal synostosis and metopic synostosis. The measures most commonly significant were centroid distances FL-PR and FL-PL and the angle OR-FR-PR. Derived centroid relationships were reproducible. Ellipsoid Analysis may offer a more refined approach to quantitative analysis of cranial shape. Symmetric and asymmetric forms can be compared directly. Relevant shape information between traditional landmarks is characterized. These techniques may have wider applicability in quantifying craniofacial morphology with increase in both specificity and general applicability over current methods.

TCP is hardly resorbed and not osteoconductive in a non-loading calvarial model.

Science.gov (United States)

Handschel, Jörg; Wiesmann, Hans Peter; Stratmann, Udo; Kleinheinz, Johannes; Meyer, Ulrich; Joos, Ulrich

2002-04-01

Tricalciumphosphate (TCP) has been used as a ceramic bone substitute material in the orthopedic field as well as in craniofacial surgery. Some controversies exist concerning the osteoconductive potential of this material in different implantation sites. This study was designed to evaluate the biological response of calvarial bone towards TCP granules under non-loading conditions to assess the potential of TCP as a biodegredable and osteoconductive bone substitue material for the cranial vault. Full-thickness non-critical size defects were made bilaterally in the calvaria of 21 adult Wistar rats. One side was filled by TCP granules, the contralateral side was left empty and used as a control. Animals were sacrified in defined time intervals up to 6 months. Bone regeneration was analyzed with special respect toward the micromorphological and microanalytical features of the material-bone interaction by electron microscopy and electron diffraction analysis. Histologic examination revealed no TCP degradation even after 6 months of implantation. In contrast, a nearly complete bone regeneration of control defects was found after 6 months. At all times TCP was surrounded by a thin fibrous layer without presence of osteoblasts and features of regular mineralization. As far as degradation and substitution are concerned, TCP is a less favourable material tinder conditions of non-loading.

Experiences in Performing Posterior Calvarial Distraction.

Science.gov (United States)

McMillan, Kevin; Lloyd, Mark; Evans, Martin; White, Nicholas; Nishikawa, Hiroshi; Rodrigues, Desiderio; Sharp, Melanie; Noons, Pete; Solanki, Guirish; Dover, Stephen

2017-05-01

The use of posterior calvarial distraction (PCD) for the management of craniosynostosis is well recognized. The advantages of using this technique include increased cranial volume, decreased intracranial pressure, relief of posterior fossa crowding, improved cerebrospinal fluid (CSF) circulation at the cranio-cervical junction with cessation, and possible resolution of syrinx.The authors retrospectively review their first 50 patients who have undergone PCD under the senior author's care in our unit.The demographics, diagnoses, intraoperative approach with techniques in distractor placement and outcomes of each patient were obtained through an electronic craniofacial database and written patient records. Analysis of complication rates (bleeding, distraction problems, CSF leaks, and infection) was included.A total of 31 boys and 19 girls underwent the procedure between October 2006 and September 2015 with a median age was 17.7 months (range 4 months to 19 years). Of those 50 children, 34 of the cohort were proven to be syndromic by genetic testing.The median length of inpatient stay was 9.4 days (range 3-43 days). Average distraction distance was 24 mm.Complications including CSF leaks, bleeding, distractor problems, and severe complications (recorded in 3 patients) are discussed. Our overall complication rate was 50%.Favorable outcomes included resolution of Chiari, syrinx, and raised intracranial pressure in the majority of patients where distraction was successful.The authors recommend that PCD should be considered the primary treatment for increasing calvarial volume. The authors discuss our experiences and technical innovations over the past decade.

The Ptch1DL mouse: a new model to study lambdoid craniosynostosis and basal cell nevus syndrome associated skeletal defects

OpenAIRE

Feng, Weiguo; Choi, Irene; Clouthier, David E.; Niswander, Lee; Williams, Trevor

2013-01-01

Mouse models provide valuable opportunities for probing the underlying pathology of human birth defects. Employing an ENU-based screen for recessive mutations affecting craniofacial anatomy we isolated a mouse strain, Dogface-like (DL), with abnormal skull and snout morphology. Examination of the skull indicated that these mice developed craniosynostosis of the lambdoid suture. Further analysis revealed skeletal defects related to the pathology of basal cell nevus syndrome (BCNS) including de...

Effects of high-frequency near-infrared diode laser irradiation on the proliferation and migration of mouse calvarial osteoblasts.

Science.gov (United States)

Kunimatsu, Ryo; Gunji, Hidemi; Tsuka, Yuji; Yoshimi, Yuki; Awada, Tetsuya; Sumi, Keisuke; Nakajima, Kengo; Kimura, Aya; Hiraki, Tomoka; Abe, Takaharu; Naoto, Hirose; Yanoshita, Makoto; Tanimoto, Kotaro

2018-01-04

Laser irradiation activates a range of cellular processes and can promote tissue repair. Here, we examined the effects of high-frequency near-infrared (NIR) diode laser irradiation on the proliferation and migration of mouse calvarial osteoblastic cells (MC3T3-E1). MC3T3-E1 cells were cultured and exposed to high-frequency (30 kHz) 910-nm diode laser irradiation at a dose of 0, 1.42, 2.85, 5.7, or 17.1 J/cm 2 . Cell proliferation was evaluated with BrdU and ATP concentration assays. Cell migration was analyzed by quantitative assessment of wound healing using the Incucyt ® ZOOM system. In addition, phosphorylation of mitogen-activated protein kinase (MAPK) family members including p38 mitogen-activated protein kinase (p38), stress-activated protein kinase/Jun-amino-terminal kinase (SAPK/JNK), and extracellular signal-regulated protein kinase (ERK)1/2) after laser irradiation was examined with western blotting. Compared to the control, cell proliferation was significantly increased by laser irradiation at a dose of 2.85, 5.7, or 17.1 J/cm 2 . Laser irradiation at a dose of 2.85 J/cm 2 induced MC3T3-E1 cells to migrate more rapidly than non-irradiated control cells. Irradiation with the high-frequency 910-nm diode laser at a dose of 2.85 J/cm 2 induced phosphorylation of MAPK/ERK1/2 15 and 30 min later. However, phosphorylation of p38 MAPK and SAPK/JNK was not changed by NIR diode laser irradiation at a dose of 2.85 J/cm 2 . Irradiation with a high-frequency NIR diode laser increased cell division and migration of MT3T3-E1 cells, possibly via MAPK/ERK signaling. These observations may be important for enhancing proliferation and migration of osteoblasts to improve regeneration of bone tissues.

Bone tissue ultrastructural defects in a mouse model for osteogenesis imperfecta: a Raman spectroscopy study

Science.gov (United States)

Chen, Tsoching; Kozloff, Kenneth M.; Goldstein, Steven A.; Morris, Michael D.

2004-07-01

Osteogenesis imperfecta (OI) is genetic defect in which the genes that code for the α1(I) or α2(I) chains of type I collagen are defective. The defects often result in substitution of a bulky amino acid for glycine, causing formation of collagen that can not form the normal triple helix. Depending on the details of the defects, the outcomes range from controllable to lethal. This study focuses on OI type IV, a more common and moderately severe form of the disease. People with the disease have a substantial increase in the risk and rate of fracture. We examine the spectroscopic consequences of these defects, using a mouse model (BRTL) that mimics OI type IV. We compare Raman images from tibial cortical tissue of wild-type mice and BRTL mice with single copy of mutation and show that both mineral to matrix ratios and collagen inter-fibril cross-links are different in wild-type and mutant mice.

Cell-printing and transfer technology applications for bone defects in mice.

Science.gov (United States)

Tsugawa, Junichi; Komaki, Motohiro; Yoshida, Tomoko; Nakahama, Ken-ichi; Amagasa, Teruo; Morita, Ikuo

2011-10-01

Bone regeneration therapy based on the delivery of osteogenic factors and/or cells has received a lot of attention in recent years since the discovery of pluripotent stem cells. We reported previously that the implantation of capillary networks engineered ex vivo by the use of cell-printing technology could improve blood perfusion. Here, we developed a new substrate prepared by coating glass with polyethylene glycol (PEG) to create a non-adhesive surface and subsequent photo-lithography to finely tune the adhesive property for efficient cell transfer. We examined the cell-transfer efficiency onto amniotic membrane and bone regenerative efficiency in murine calvarial bone defect. Cell transfer of KUSA-A1 cells (murine osteoblasts) to amniotic membrane was performed for 1 h using the substrates. Cell transfer using the substrate facilitated cell engraftment onto the amniotic membrane compared to that by direct cell inoculation. KUSA-A1 cells transferred onto the amniotic membrane were applied to critical-sized calvarial bone defects in mice. Micro-computed tomography (micro-CT) analysis showed rapid and effective bone formation by the cell-equipped amniotic membrane. These results indicate that the cell-printing and transfer technology used to create the cell-equipped amniotic membrane was beneficial for the cell delivery system. Our findings support the development of a biologically stable and effective bone regeneration therapy. Copyright © 2011 John Wiley & Sons, Ltd.

Association of mesenchymal stem cells with platelet rich plasma on the repair of critical calvarial defects in mice Associação de células-tronco mesenquimais com plasma rico em plaquetas na reparação de defeitos críticos em calvária de camundongos

Directory of Open Access Journals (Sweden)

Betânia Souza Monteiro

2012-03-01

Full Text Available PURPOSE: To evaluate the effects of mesenchymal stem cells (MSC from eight mice C57BL/6 gfp+ bone marrows expanded in cultures associated with platelets rich plasma (PRP deriving from another eight mice, in the repair of critical defects in calvarial bone produced in twenty-four adult isogenic mice C57BL/6. METHODS: The animals were submitted to a cranial defect of 6.0mm in diameter and divided into two equal experimental groups. Control group did not receive treatment and the treated group received a MSC pellet containing 1.0 x 10(7 cells/mL associated with 50.0µL of plasma gel containing 1.0 x 10(9 autologous platelets within the defect. RESULTS: In the treated group was observed process of angiogenesis and bone repair better than control group. CONCLUSION: Mesenchymal stem cells derived from bone marrow of C57BL/6 gfp+ mice associated with PRP gel applied in bone critical defects produced in calvarial contributes positively to the process of bone repair.OBJETIVO: Avaliar os efeitos da associação das células-tronco mesenquimais (MSC oriundas da medula óssea de oito camundongos jovens C57BL/6 gfp+ e expandidas em culturas, com Plasma Rico em Plaquetas (PRP provenientes de outros oito camundongos, na reparação de defeitos críticos confeccionados em calvária de 24 camundongos adultos C57BL/6. MÉTODOS: Os animais foram submetidos a um defeito craniano de 6,0mm de diâmetro e separados em dois grupos experimentais iguais. O grupo controle não recebeu tratamento e no grupo tratado foi administrado, no interior do defeito, pellet de MSC contendo 1,0 x 10(7 células/mL associado com 50,0µL de plasma em gel autólogo contendo 1,0 x 10(9 plaquetas. RESULTADOS: No grupo tratado verificou-se processo de angiogênese e reparação óssea superior ao grupo controle. CONCLUSÃO: A associação das células-tronco mesenquimais (MSC derivadas da medula óssea de camundongos C57BL/6 gfp+ com gel de PRP aplicadas em defeitos ósseos cr

Fronto-Orbital Advancement and Total Calvarial Remodelling for Craniosynostosis

International Nuclear Information System (INIS)

Haq, E. U.; Aman, S.; Tammimy, M. S.; Ahmad, R. S.

2014-01-01

Objective: To describe the results of fronto-orbital advancement and remodelling for craniosynostosis in children. Study Design: Case series. Place and Duration of Study: Department of Plastic Surgery, Combined Military Hospital, Rawalpindi, from June 2009 to June 2012. Methodology: All the patients with cranial suture synostosis operated were included in the study. Those patients who were lost to follow-up were excluded. Variables considered were age, gender, type of synostosis, intracranial pressure, and history of previous surgeries for the same problem. Outcome measures were studied in terms of improvement of skull measurements (anteroposterior and bicoronal), duration of surgery, hospital stay, blood transfusions, complications and parents satisfaction. Results: A total of 36 patients were included in the study. Male to female ratio was 3:1. The age ranged from 5 to 54 months. Thirty two patients presented with non-syndromic and four with syndromic craniosynostosis. Fronto orbital advancement and total calvarial remodelling was done in 26 and 10 patients respectively. There was improvement in the skull measurements and the parents were satisfied in all cases with the skull shape. Complications occurred in 11.1% including chest and wound infection and one death. Conclusion: Fronto-orbital advancement and remodelling is an effective procedure for the correction of craniosynostosis, however, individual cases may require other procedures like total calvarial remodelling. (author)

Regeneration of calvarial defects by a composite of bioerodible polyorthoester and demineralized bone in rats

DEFF Research Database (Denmark)

Solheim, E; Pinholt, E M; Bang, G

1992-01-01

A study was performed to evaluate regeneration of defects in rat calvaria either unfilled or filled with a bioerodible polyorthoester only, demineralized bone only, or a composite of both. At 4 weeks, histological and radiographic studies showed that defects filled with a composite of bioerodible...... polyorthoester and demineralized bone or demineralized bone alone were bridged by bone. Unfilled defects or defects filled with polyorthoester only did not heal. The polyorthoester caused slight inflammation that subsided by 3 weeks, and only traces of the filler could be detected at 4 weeks. The polyorthoester...... provided local hemostasis when used either alone or in composites with demineralized bone. The composite implant was moldable, easily contoured, and technically easier to use than demineralized bone alone....

Biomechanical Evaluation of Rat Skull Defects, 1, 3, and 6 Months after Implantation with Osteopromotive Substances

DEFF Research Database (Denmark)

Jones, Leigh Robert; Thomsen, Jesper Skovhus; Mosekilde, Lis

2007-01-01

as unfilled controls. The repaired defects were evaluated biomechanically using a modified punch out test 1, 3, or 6 months postoperatively. Results: The maximum load carried in the DBM group was significantly higher than in the bone chips, hydroxyapatite, and control groups after one month of healing......Purpose: To compare the mechanical strength of surgically created and healed rat calvarial defects having been filled with three different osteopromotive substances: hydroxyapatite, intramembraneous demineralised bone matrix (DBM), and autogenous bone chips. Material: Sixty adult male Wistar rats...... were divided into three groups of 20 animals, each group representing healing times of one, three, or six months. Methods: Identical 5 mm bilateral critical size defects were trephined into the parietal bones and hydroxyapatite, DBM, or autogenous bone chips were implanted into the defects, or left...

Pantothenate kinase-associated neurodegeneration: altered mitochondria membrane potential and defective respiration in Pank2 knock-out mouse model.

Science.gov (United States)

Brunetti, Dario; Dusi, Sabrina; Morbin, Michela; Uggetti, Andrea; Moda, Fabio; D'Amato, Ilaria; Giordano, Carla; d'Amati, Giulia; Cozzi, Anna; Levi, Sonia; Hayflick, Susan; Tiranti, Valeria

2012-12-15

Neurodegeneration with brain iron accumulation (NBIA) comprises a group of neurodegenerative disorders characterized by high brain content of iron and presence of axonal spheroids. Mutations in the PANK2 gene, which encodes pantothenate kinase 2, underlie an autosomal recessive inborn error of coenzyme A metabolism, called pantothenate kinase-associated neurodegeneration (PKAN). PKAN is characterized by dystonia, dysarthria, rigidity and pigmentary retinal degeneration. The pathogenesis of this disorder is poorly understood and, although PANK2 is a mitochondrial protein, perturbations in mitochondrial bioenergetics have not been reported. A knock-out (KO) mouse model of PKAN exhibits retinal degeneration and azoospermia, but lacks any neurological phenotype. The absence of a clinical phenotype has partially been explained by the different cellular localization of the human and murine PANK2 proteins. Here we demonstrate that the mouse Pank2 protein localizes to mitochondria, similar to its human orthologue. Moreover, we show that Pank2-defective neurons derived from KO mice have an altered mitochondrial membrane potential, a defect further corroborated by the observations of swollen mitochondria at the ultra-structural level and by the presence of defective respiration.

3D-Printed Atsttrin-Incorporated Alginate/Hydroxyapatite Scaffold Promotes Bone Defect Regeneration with TNF/TNFR Signaling Involvement.

Science.gov (United States)

Wang, Quan; Xia, Qingqing; Wu, Yan; Zhang, Xiaolei; Wen, Feiqiu; Chen, Xiaowen; Zhang, Shufang; Heng, Boon Chin; He, Yong; Ouyang, Hong-Wei

2015-08-05

High expression levels of pro-inflammatory tumor necrosis factor (TNF)-α within bone defects can decelerate and impair bone regeneration. However, there are few available bone scaffolds with anti-inflammatory function. The progranulin (PGRN)-derived engineered protein, Atsttrin, is known to exert antagonistic effects on the TNF-α function. Hence, this study investigates whether 3D-printed Atsttrin-incorporated alginate(Alg)/hydroxyapatite(nHAp) scaffolds can facilitate bone healing through affecting the TNF/TNFR signaling. A 3D bioprinting system is used to fabricate Atsttrin-Alg/nHAp composite scaffolds, and the Atsttrin release from this scaffold is characterized, followed by evaluation of its efficacy on bone regeneration both in vitro and in vivo. The 3D-printed Atsttrin-Alg/nHAp scaffold exhibits a precisely defined structure, can sustain Atsttrin release for at least 5 days, has negligible cytotoxicity, and supports cell adhesion. Atsttrin can also attenuate the suppressive effects of TNF-α on BMP-2-induced osteoblastic differentiation in vitro. The 3D-printed Atsttrin-Alg/nHAp scaffold significantly reduces the number of TNF-α positive cells within wound sites, 7 days after post-calvarial defect surgery. Additionally, histological staining and X-ray scanning results also show that the 3D-printed Atsttrin-Alg/nHAp scaffold enhances the regeneration of mice calvarial bone defects. These findings thus demonstrate that the precise structure and anti-inflammatory properties of 3D-printed Atsttrin-Alg/nHAp scaffolds may promote bone defect repair. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The App-Runx1 region is critical for birth defects and electrocardiographic dysfunctions observed in a Down syndrome mouse model.

Directory of Open Access Journals (Sweden)

Matthieu Raveau

2012-05-01

Full Text Available Down syndrome (DS leads to complex phenotypes and is the main genetic cause of birth defects and heart diseases. The Ts65Dn DS mouse model is trisomic for the distal part of mouse chromosome 16 and displays similar features with post-natal lethality and cardiovascular defects. In order to better understand these defects, we defined electrocardiogram (ECG with a precordial set-up, and we found conduction defects and modifications in wave shape, amplitudes, and durations in Ts65Dn mice. By using a genetic approach consisting of crossing Ts65Dn mice with Ms5Yah mice monosomic for the App-Runx1 genetic interval, we showed that the Ts65Dn viability and ECG were improved by this reduction of gene copy number. Whole-genome expression studies confirmed gene dosage effect in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah hearts and showed an overall perturbation of pathways connected to post-natal lethality (Coq7, Dyrk1a, F5, Gabpa, Hmgn1, Pde10a, Morc3, Slc5a3, and Vwf and heart function (Tfb1m, Adam19, Slc8a1/Ncx1, and Rcan1. In addition cardiac connexins (Cx40, Cx43 and sodium channel sub-units (Scn5a, Scn1b, Scn10a were found down-regulated in Ts65Dn atria with additional down-regulation of Cx40 in Ts65Dn ventricles and were likely contributing to conduction defects. All these data pinpoint new cardiac phenotypes in the Ts65Dn, mimicking aspects of human DS features and pathways altered in the mouse model. In addition they highlight the role of the App-Runx1 interval, including Sod1 and Tiam1, in the induction of post-natal lethality and of the cardiac conduction defects in Ts65Dn. These results might lead to new therapeutic strategies to improve the care of DS people.

Partial thickness autologus calvarial bone orbitocranioplasty for a sphenorbital encephalocele presenting as pulsatile exophthalmos

OpenAIRE

Trivedi, Adarsh; Garg, Amrish Kumar; Hiran, Subodh

2015-01-01

Basal encephalocele accounts only 1.5% of all encephaloceles. But Sphenorbital encephalocele is the rarest cause of herniation of brain into orbit leading to pulsatile exphothalmos. Authors presenting a case of sphenorbital encephalocele in a 16 yrs old girl successsfully managed by orbitcranioplasty by partilal thickness autologus calvarial bone graft.

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells

Energy Technology Data Exchange (ETDEWEB)

Yeh, Lee-Chuan C.; Ford, Jeffery J. [Department of Biochemistry, The University of Texas Health Science Center at San Antonio, TX (United States); Lee, John C. [Department of Biochemistry, The University of Texas Health Science Center at San Antonio, TX (United States); The Sam and Ann Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, TX (United States); Adamo, Martin L., E-mail: adamo@biochem.uthscsa.edu [Department of Biochemistry, The University of Texas Health Science Center at San Antonio, TX (United States); The Sam and Ann Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, TX (United States)

2014-07-18

Highlights: • Palmitate inhibits osteoblast differentiation. • Fatty acid synthase. • PPARγ. • Acetyl Co-A carboxylase inhibitor TOFA. • Fetal rat calvarial cell culture. - Abstract: Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects.

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells

International Nuclear Information System (INIS)

Yeh, Lee-Chuan C.; Ford, Jeffery J.; Lee, John C.; Adamo, Martin L.

2014-01-01

Highlights: • Palmitate inhibits osteoblast differentiation. • Fatty acid synthase. • PPARγ. • Acetyl Co-A carboxylase inhibitor TOFA. • Fetal rat calvarial cell culture. - Abstract: Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects

Electrospun PLLA nanofiber scaffolds and their use in combination with BMP-2 for reconstruction of bone defects.

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Markus D Schofer

Full Text Available Adequate migration and differentiation of mesenchymal stem cells is essential for regeneration of large bone defects. To achieve this, modern graft materials are becoming increasingly important. Among them, electrospun nanofiber scaffolds are a promising approach, because of their high physical porosity and potential to mimic the extracellular matrix (ECM.The objective of the present study was to examine the impact of electrospun PLLA nanofiber scaffolds on bone formation in vivo, using a critical size rat calvarial defect model. In addition we analyzed whether direct incorporation of bone morphogenetic protein 2 (BMP-2 into nanofibers could enhance the osteoinductivity of the scaffolds. Two critical size calvarial defects (5 mm were created in the parietal bones of adult male Sprague-Dawley rats. Defects were either (1 left unfilled, or treated with (2 bovine spongiosa, (3 PLLA scaffolds alone or (4 PLLA/BMP-2 scaffolds. Cranial CT-scans were taken at fixed intervals in vivo. Specimens obtained after euthanasia were processed for histology, histomorphometry and immunostaining (Osteocalcin, BMP-2 and Smad5.PLLA scaffolds were well colonized with cells after implantation, but only showed marginal ossification. PLLA/BMP-2 scaffolds showed much better bone regeneration and several ossification foci were observed throughout the defect. PLLA/BMP-2 scaffolds also stimulated significantly faster bone regeneration during the first eight weeks compared to bovine spongiosa. However, no significant differences between these two scaffolds could be observed after twelve weeks. Expression of osteogenic marker proteins in PLLA/BMP-2 scaffolds continuously increased throughout the observation period. After twelve weeks osteocalcin, BMP-2 and Smad5 were all significantly higher in the PLLA/BMP-2 group than in all other groups.Electrospun PLLA nanofibers facilitate colonization of bone defects, while their use in combination with BMP-2 also increases bone

A spontaneous and novel Pax3 mutant mouse that models Waardenburg syndrome and neural tube defects.

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Ohnishi, Tetsuo; Miura, Ikuo; Ohba, Hisako; Shimamoto, Chie; Iwayama, Yoshimi; Wakana, Shigeharu; Yoshikawa, Takeo

2017-04-05

Genes responsible for reduced pigmentation phenotypes in rodents are associated with human developmental defects, such as Waardenburg syndrome, where patients display congenital deafness along with various abnormalities mostly related to neural crest development deficiency. In this study, we identified a spontaneous mutant mouse line Rwa, which displays variable white spots on mouse bellies and white digits and tail, on a C57BL/6N genetic background. Curly tail and spina bifida were also observed, although at a lower penetrance. These phenotypes were dominantly inherited by offspring. We searched for the genetic mechanism of the observed phenotypes. We harnessed a rapid mouse gene mapping system newly developed in our laboratories to identify a responsible gene. We detected a region within chromosome 1 as a probable locus for the causal mutation. Dense mapping using interval markers narrowed the locus down to a 670-kbp region, containing four genes including Pax3, a gene known to be implicated in the types I and III Waardenburg syndrome. Extensive mutation screening of Pax3 detected an 841-bp deletion, spanning the promoter region and intron 1 of the gene. The defective allele of Pax3, named Pax3 Rwa , lacked the first coding exon and co-segregated perfectly with the phenotypes, confirming its causal nature. The genetic background of Rwa mice is almost identical to that of inbred C57BL/6N. These results highlight Pax3 Rwa mice as a beneficial tool for analyzing biological processes involving Pax3, in particular the development and migration of neural crest cells and melanocytes. Copyright © 2017 Elsevier B.V. All rights reserved.

Carbon nanohorns accelerate bone regeneration in rat calvarial bone defect

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Kasai, Takao; Iizuka, Tadashi; Kanamori, Takeshi; Yokoyama, Atsuro [Department of Oral Functional Prosthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Kita 13, Nishi 7, Kita-ku, Sapporo, Hokkaido 060-8586 (Japan); Matsumura, Sachiko; Shiba, Kiyotaka [Division of Protein Engineering, Cancer Institute, Japanese Foundation for Cancer Research, 3-8-31, Ariake, koutou-ku, Tokyo 135-8550 (Japan); Yudasaka, Masako; Iijima, Sumio, E-mail: tkasai@den.hokudai.ac.jp [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology, Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565 (Japan)

2011-02-11

A recent study showed that carbon nanohorns (CNHs) have biocompatibility and possible medical uses such as in drug delivery systems. It was reported that some kinds of carbon nanomaterials such as carbon nanotubes were useful for bone formation. However, the effect of CNHs on bone tissue has not been clarified. The purpose of this study was to evaluate the effect of CNHs on bone regeneration and their possible application for guided bone regeneration (GBR). CNHs dispersed in ethanol were fixed on a porous polytetrafluoroethylene membrane by vacuum filtration. Cranial defects were created in rats and covered by a membrane with/without CNHs. At two weeks, bone formation under the membrane with CNHs had progressed more than under that without CNHs and numerous macrophages were observed attached to CNHs. At eight weeks, there was no significant difference in the amount of newly formed bone between the groups and the appearance of macrophages was decreased compared with that at two weeks. Newly formed bone attached to some CNHs directly. These results suggest that macrophages induced by CNHs are related to bone regeneration. In conclusion, the present study indicates that CNHs are compatible with bone tissue and effective as a material for GBR.

Piezosurgery for the repair of middle cranial fossa meningoencephaloceles.

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Acharya, Aanand N; Rajan, Gunesh P

2015-03-01

To describe the use of a piezosurgery medical device to perform a craniotomy and produce a split calvarial graft for the repair of middle cranial fossa meningoencephaloceles. Retrospective case review. Tertiary referral hospital. Ten consecutive patients undergoing middle cranial fossa approach for the repair of meningoencephaloceles. Therapeutic. Intraoperative and postoperative complications, success rate as defined by the ability to fashion a split calvarial graft that achieves complete closure of the tegmen defect. As a secondary outcome measure, evidence of integration of the split calvarial bone graft with the adjacent skull base was assessed. There were no intraoperative or postoperative complications. An appropriately sized calvarial bone graft was produced, and complete closure of the tegmen defect was achieved in all 10 cases. Computed tomography demonstrated evidence of integration of the bone graft in eight cases between 4 and 9 months after surgery. The piezosurgery medical device provides a safe and effective means by which the middle fossa craniotomy and split calvarial bone graft can be produced to repair defects of the middle fossa tegmen, with integration of the bone graft in the majority of cases.

Establishment of a mouse model with misregulated chromosome condensation due to defective Mcph1 function.

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Marc Trimborn

Full Text Available Mutations in the human gene MCPH1 cause primary microcephaly associated with a unique cellular phenotype with premature chromosome condensation (PCC in early G2 phase and delayed decondensation post-mitosis (PCC syndrome. The gene encodes the BRCT-domain containing protein microcephalin/BRIT1. Apart from its role in the regulation of chromosome condensation, the protein is involved in the cellular response to DNA damage. We report here on the first mouse model of impaired Mcph1-function. The model was established based on an embryonic stem cell line from BayGenomics (RR0608 containing a gene trap in intron 12 of the Mcph1 gene deleting the C-terminal BRCT-domain of the protein. Although residual wild type allele can be detected by quantitative real-time PCR cell cultures generated from mouse tissues bearing the homozygous gene trap mutation display the cellular phenotype of misregulated chromosome condensation that is characteristic for the human disorder, confirming defective Mcph1 function due to the gene trap mutation. While surprisingly the DNA damage response (formation of repair foci, chromosomal breakage, and G2/M checkpoint function after irradiation appears to be largely normal in cell cultures derived from Mcph1(gt/gt mice, the overall survival rates of the Mcph1(gt/gt animals are significantly reduced compared to wild type and heterozygous mice. However, we could not detect clear signs of premature malignant disease development due to the perturbed Mcph1 function. Moreover, the animals show no obvious physical phenotype and no reduced fertility. Body and brain size are within the range of wild type controls. Gene expression on RNA and protein level did not reveal any specific pattern of differentially regulated genes. To the best of our knowledge this represents the first mammalian transgenic model displaying a defect in mitotic chromosome condensation and is also the first mouse model for impaired Mcph1-function.

Establishment of a mouse model with misregulated chromosome condensation due to defective Mcph1 function.

Science.gov (United States)

Trimborn, Marc; Ghani, Mahdi; Walther, Diego J; Dopatka, Monika; Dutrannoy, Véronique; Busche, Andreas; Meyer, Franziska; Nowak, Stefanie; Nowak, Jean; Zabel, Claus; Klose, Joachim; Esquitino, Veronica; Garshasbi, Masoud; Kuss, Andreas W; Ropers, Hans-Hilger; Mueller, Susanne; Poehlmann, Charlotte; Gavvovidis, Ioannis; Schindler, Detlev; Sperling, Karl; Neitzel, Heidemarie

2010-02-16

Mutations in the human gene MCPH1 cause primary microcephaly associated with a unique cellular phenotype with premature chromosome condensation (PCC) in early G2 phase and delayed decondensation post-mitosis (PCC syndrome). The gene encodes the BRCT-domain containing protein microcephalin/BRIT1. Apart from its role in the regulation of chromosome condensation, the protein is involved in the cellular response to DNA damage. We report here on the first mouse model of impaired Mcph1-function. The model was established based on an embryonic stem cell line from BayGenomics (RR0608) containing a gene trap in intron 12 of the Mcph1 gene deleting the C-terminal BRCT-domain of the protein. Although residual wild type allele can be detected by quantitative real-time PCR cell cultures generated from mouse tissues bearing the homozygous gene trap mutation display the cellular phenotype of misregulated chromosome condensation that is characteristic for the human disorder, confirming defective Mcph1 function due to the gene trap mutation. While surprisingly the DNA damage response (formation of repair foci, chromosomal breakage, and G2/M checkpoint function after irradiation) appears to be largely normal in cell cultures derived from Mcph1(gt/gt) mice, the overall survival rates of the Mcph1(gt/gt) animals are significantly reduced compared to wild type and heterozygous mice. However, we could not detect clear signs of premature malignant disease development due to the perturbed Mcph1 function. Moreover, the animals show no obvious physical phenotype and no reduced fertility. Body and brain size are within the range of wild type controls. Gene expression on RNA and protein level did not reveal any specific pattern of differentially regulated genes. To the best of our knowledge this represents the first mammalian transgenic model displaying a defect in mitotic chromosome condensation and is also the first mouse model for impaired Mcph1-function.

Effect of calvarial burring on resorption of onlay cranial bone graft.

Science.gov (United States)

Hassanein, Aladdin H; Clune, James E; Mulliken, John B; Arany, Praveen R; Rogers, Gary F; Kulungowski, Ann M; Greene, Arin K

2012-09-01

Variable resorption occurs whenever calvarial bone graft is used for onlay cranioplasty. The recipient ectocortex may be burred to expose vessels and osteocytes to maximize healing. The purpose of this study was to determine whether abrading the recipient site improves the volume of onlay graft. The parietal bones of 17 rabbits were sectioned into split-thickness and full-thickness grafts. The right frontal cortex was abraded with a bur to punctate bleeding. Pairs of split-thickness (n = 48) or full-thickness (n = 20) grafts were onlayed to the burred right frontal bone and to the nonburred left frontal bone. Micro-computed tomography was used to determine graft volume immediately postoperatively and 16 weeks later. Histology, including tartrate-resistant acid phosphatase staining, was performed to quantify vascular channels and osteoclasts per high-power field 10 days postoperatively. Split-thickness graft volume decreased 58.0% when placed on the burred calvarial site, compared with grafts on the nonburred cortex (28.4%) (P = 0.01). Full-thickness grafts showed a similar trend: greater resorption (39.1%) when onlayed onto abraded calvaria compared with nonburred ectocortex (26.0%) (P = 0.11). Split-thickness graft orientation (cortical vs cancellous side in contact with the recipient site) did not affect resorption (P = 0.67). Onlay grafts placed on the burred recipient site had more vascular channels (11.8) and osteoclasts (5.7), compared with grafts over nonabraded cortex (3.4 and 4.2, respectively) (P cranial bone grafting promotes resorption, possibly by increasing vascularization and osteoclastic activity. This technique cannot be recommended.

Molecular cloning of a mouse DNA repair gene that complements the defect of group-A xeroderma pigmentosum

International Nuclear Information System (INIS)

Tanaka, K.; Satokata, I.; Ogita, Z.; Uchida, T.; Okada, Y.

1989-01-01

For isolation of the gene responsible for xeroderma pigmentosum (XP) complementation group A, plasmid pSV2gpt and genomic DNA from a mouse embryo were cotransfected into XP2OSSV cells, a group-A XP cell line. Two primary UV-resistant XP transfectants were isolated from about 1.6 X 10(5) pSV2gpt-transformed XP colonies. pSV2gpt and genomic DNA from the primary transfectants were again cotransfected into XP2OSSV cells and a secondary UV-resistant XP transfectant was obtained by screening about 4.8 X 10(5) pSV2gpt-transformed XP colonies. The secondary transfectant retained fewer mouse repetitive sequences. A mouse gene that complements the defect of XP2OSSV cells was cloned into an EMBL3 vector from the genome of a secondary transfectant. Transfections of the cloned DNA also conferred UV resistance on another group-A XP cell line but not on XP cell lines of group C, D, F, or G. Northern blot analysis of poly(A)+ RNA with a subfragment of cloned mouse DNA repair gene as the probe revealed that an approximately 1.0 kilobase mRNA was transcribed in the donor mouse embryo and secondary transfectant, and approximately 1.0- and approximately 1.3-kilobase mRNAs were transcribed in normal human cells, but none of these mRNAs was detected in three strains of group-A XP cells. These results suggest that the cloned DNA repair gene is specific for group-A XP and may be the mouse homologue of the group-A XP human gene

Defects in the medial entorhinal cortex and dentate gyrus in the mouse model of Sanfilippo syndrome type B.

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Kazuhiro Ohmi

Full Text Available Sanfilippo syndrome type B (MPS IIIB is characterized by profound mental retardation in childhood, dementia and death in late adolescence; it is caused by deficiency of α-N-acetylglucosaminidase and resulting lysosomal storage of heparan sulfate. A mouse model, generated by homologous recombination of the Naglu gene, was used to study pathological changes in the brain. We found earlier that neurons in the medial entorhinal cortex (MEC and the dentate gyrus showed a number of secondary defects, including the presence of hyperphosphorylated tau (Ptau detected with antibodies raised against Ptau in Alzheimer disease brain. By further use of immunohistochemistry, we now show staining in neurons of the same area for beta amyloid, extending the resemblance to Alzheimer disease. Ptau inclusions in the dentate gyrus of MPS IIIB mice were reduced in number when the mice were administered LiCl, a specific inhibitor of Gsk3β. Additional proteins found elevated in MEC include proteins involved in autophagy and the heparan sulfate proteoglycans, glypicans 1 and 5, the latter closely related to the primary defect. The level of secondary accumulations was associated with elevation of glypican, as seen by comparing brains of mice at different ages or with different mucopolysaccharide storage diseases. The MEC of an MPS IIIA mouse had the same intense immunostaining for glypican 1 and other markers as MPS IIIB, while MEC of MPS I and MPS II mice had weak staining, and MEC of an MPS VI mouse had no staining at all for the same proteins. A considerable amount of glypican was found in MEC of MPS IIIB mice outside of lysosomes. We propose that it is the extralysosomal glypican that would be harmful to neurons, because its heparan sulfate branches could potentiate the formation of Ptau and beta amyloid aggregates, which would be toxic as well as difficult to degrade.

The relationship between cell killing, chromosome aberrations, spindle defects, and mitotic delay in mouse lymphoma cells of differential sensitivity to X-rays

International Nuclear Information System (INIS)

Scott, D.; Zampetti-Bosseler, F.

1980-01-01

A study has been made of the effects of x radiation on an ultrasensitive subline of L5178Y mouse lymphoma cells. It has been shown that at survival levels above about 20 per cent, chromosome structural aberrations which lead to bridges and fragments at anaphase are about four times more frequent than spindle defects. The results demonstrated the higher frequency of structural aberrations and spindle defects, and the greater mitotic delay in the X-ray-sensitive than in the X-ray-resistant cell line. A model is proposed which causally relates these end-points to cell killing and DNA repair. (author)

Polymorphic human (CTAT)n microsatellite provides a conserved linkage marker for mouse mutants causing cleft palate, vestibular defects, obesity and ataxia

Energy Technology Data Exchange (ETDEWEB)

Griffith, A.J.; Burgess, D.L.; Kohrman, D. [Univ. of MIchigan, Ann Arbor, MI (United States)] [and others

1994-09-01

The Twirler mutation (Tw) causing cleft palate {plus_minus} cleft lip, vestibular defects and obesity is located within 0.5 cM of an ataxia locus (ax) on mouse chromosome 18. We identified a transgene-induced insertional mutation with vestibular and craniofacial defects that appears to be a new allele of Twirler. Mouse DNA flanking the transgene insertion site was isolated from a cosmid library. An evolutionarily conserved, zoo blot positive cosmid subclone was used to probe a human {lambda} genomic library. From the sequence of a highly homologous human {lambda} clone, we designed STS primers and screened a human P1 library. DNA from two positive P1 clones was hybridized with simple sequence probes, and a (CTAT){sub 12} repeat was detected. Analysis of 62 CEPH parents with primers flanking the repeat identified six alleles containing 9 to 14 copies of the repeat, at frequencies of 0.17, 0.17, 0.17, 0.27, 0.15 and 0.07, respectively. The observed heterozygosity was 49/62 with a calculated PIC value of 0.76. This polymorphic microsatellite marker, designated Umi3, was mapped to the predicted conserved human linkage group by analysis of somatic cell hybrid panels. The anticipated short distance between Umi3 and the disease genes will facilitate detection of linkage in small families. We would like to type appropriate human pedigrees with Umi3 in order to identify patients with inherited disorders homologous to the mouse mutations Twirler and ataxia.

Bioenergetics during calvarial osteoblast differentiation reflect strain differences in bone mass.

Science.gov (United States)

Guntur, Anyonya R; Le, Phuong T; Farber, Charles R; Rosen, Clifford J

2014-05-01

Osteoblastogenesis is the process by which mesenchymal stem cells differentiate into osteoblasts that synthesize collagen and mineralize matrix. The pace and magnitude of this process are determined by multiple genetic and environmental factors. Two inbred strains of mice, C3H/HeJ and C57BL/6J, exhibit differences in peak bone mass and bone formation. Although all the heritable factors that differ between these strains have not been elucidated, a recent F1 hybrid expression panel (C3H × B6) revealed major genotypic differences in osteoblastic genes related to cellular respiration and oxidative phosphorylation. Thus, we hypothesized that the metabolic rate of energy utilization by osteoblasts differed by strain and would ultimately contribute to differences in bone formation. In order to study the bioenergetic profile of osteoblasts, we measured oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) first in a preosteoblastic cell line MC3T3-E1C4 and subsequently in primary calvarial osteoblasts from C3H and B6 mice at days 7, 14, and 21 of differentiation. During osteoblast differentiation in media containing ascorbic acid and β-glycerophosphate, all 3 cell types increased their oxygen consumption and extracellular acidification rates compared with the same cells grown in regular media. These increases are sustained throughout differentiation. Importantly, C3H calvarial osteoblasts had greater oxygen consumption rates than B6 consistent with their in vivo phenotype of higher bone formation. Interestingly, osteoblasts utilized both oxidative phosphorylation and glycolysis during the differentiation process although mature osteoblasts were more dependent on glycolysis at the 21-day time point than oxidative phosphorylation. Thus, determinants of oxygen consumption reflect strain differences in bone mass and provide the first evidence that during collagen synthesis osteoblasts use both glycolysis and oxidative phosphorylation to synthesize and

Defects in GPI biosynthesis perturb Cripto signaling during forebrain development in two new mouse models of holoprosencephaly

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David M. McKean

2012-07-01

Holoprosencephaly is the most common forebrain defect in humans. We describe two novel mouse mutants that display a holoprosencephaly-like phenotype. Both mutations disrupt genes in the glycerophosphatidyl inositol (GPI biosynthesis pathway: gonzo disrupts Pign and beaker disrupts Pgap1. GPI anchors normally target and anchor a diverse group of proteins to lipid raft domains. Mechanistically we show that GPI anchored proteins are mislocalized in GPI biosynthesis mutants. Disruption of the GPI-anchored protein Cripto (mouse and TDGF1 (human ortholog have been shown to result in holoprosencephaly, leading to our hypothesis that Cripto is the key GPI anchored protein whose altered function results in an HPE-like phenotype. Cripto is an obligate Nodal co-factor involved in TGFβ signaling, and we show that TGFβ signaling is reduced both in vitro and in vivo. This work demonstrates the importance of the GPI anchor in normal forebrain development and suggests that GPI biosynthesis genes should be screened for association with human holoprosencephaly.

Biotin-deficient diet induces chromosome misalignment and spindle defects in mouse oocytes.

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Tsuji, Ai; Nakamura, Toshinobu; Shibata, Katsumi

2015-01-01

Increased abnormal oocytes due to meiotic chromosome misalignment and spindle defects lead to elevated rates of infertility, miscarriage, and trisomic conceptions. Here, we investigated the effect of biotin deficiency on oocyte quality. Three-week-old female ICR mice were fed a biotin-deficient or control diet (0, 0.004 g biotin/kg diet) for 21 days. On day 22, these mouse oocytes were analyzed by immunofluorescence. Due to biotin, undernutrition increased the frequency of abnormal oocytes (the biotin deficient vs. control: 40 vs. 16%). Next, the remaining mice in the biotin-deficient group were fed a control or biotin-deficient diet from day 22 to 42. Although biotin nutritional status in the recovery group was restored, the frequency of abnormal oocytes in the recovery group was still higher than that in the control group (48 vs. 18%). Our results indicate that steady, sufficient biotin intake is required for the production of high-quality oocytes in mice.

A retrotransposon insertion in the 5' regulatory domain of Ptf1a results in ectopic gene expression and multiple congenital defects in Danforth's short tail mouse.

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Francesca Lugani

Full Text Available Danforth's short tail mutant (Sd mouse, first described in 1930, is a classic spontaneous mutant exhibiting defects of the axial skeleton, hindgut, and urogenital system. We used meiotic mapping in 1,497 segregants to localize the mutation to a 42.8-kb intergenic segment on chromosome 2. Resequencing of this region identified an 8.5-kb early retrotransposon (ETn insertion within the highly conserved regulatory sequences upstream of Pancreas Specific Transcription Factor, 1a (Ptf1a. This mutation resulted in up to tenfold increased expression of Ptf1a as compared to wild-type embryos at E9.5 but no detectable changes in the expression levels of other neighboring genes. At E9.5, Sd mutants exhibit ectopic Ptf1a expression in embryonic progenitors of every organ that will manifest a developmental defect: the notochord, the hindgut, and the mesonephric ducts. Moreover, at E 8.5, Sd mutant mice exhibit ectopic Ptf1a expression in the lateral plate mesoderm, tail bud mesenchyme, and in the notochord, preceding the onset of visible defects such as notochord degeneration. The Sd heterozygote phenotype was not ameliorated by Ptf1a haploinsufficiency, further suggesting that the developmental defects result from ectopic expression of Ptf1a. These data identify disruption of the spatio-temporal pattern of Ptf1a expression as the unifying mechanism underlying the multiple congenital defects in Danforth's short tail mouse. This striking example of an enhancer mutation resulting in profound developmental defects suggests that disruption of conserved regulatory elements may also contribute to human malformation syndromes.

Peroxisomes in Different Skeletal Cell Types during Intramembranous and Endochondral Ossification and Their Regulation during Osteoblast Differentiation by Distinct Peroxisome Proliferator-Activated Receptors.

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Guofeng Qian

Full Text Available Ossification defects leading to craniofacial dysmorphism or rhizomelia are typical phenotypes in patients and corresponding knockout mouse models with distinct peroxisomal disorders. Despite these obvious skeletal pathologies, to date no careful analysis exists on the distribution and function of peroxisomes in skeletal tissues and their alterations during ossification. Therefore, we analyzed the peroxisomal compartment in different cell types of mouse cartilage and bone as well as in primary cultures of calvarial osteoblasts. The peroxisome number and metabolism strongly increased in chondrocytes during endochondral ossification from the reserve to the hypertrophic zone, whereas in bone, metabolically active osteoblasts contained a higher numerical abundance of this organelle than osteocytes. The high abundance of peroxisomes in these skeletal cell types is reflected by high levels of Pex11β gene expression. During culture, calvarial pre-osteoblasts differentiated into secretory osteoblasts accompanied by peroxisome proliferation and increased levels of peroxisomal genes and proteins. Since many peroxisomal genes contain a PPAR-responsive element, we analyzed the gene expression of PPARɑ/ß/ɣ in calvarial osteoblasts and MC3T3-E1 cells, revealing higher levels for PPARß than for PPARɑ and PPARɣ. Treatment with different PPAR agonists and antagonists not only changed the peroxisomal compartment and associated gene expression, but also induced complex alterations of the gene expression patterns of the other PPAR family members. Studies in M3CT3-E1 cells showed that the PPARß agonist GW0742 activated the PPRE-mediated luciferase expression and up-regulated peroxisomal gene transcription (Pex11, Pex13, Pex14, Acox1 and Cat, whereas the PPARß antagonist GSK0660 led to repression of the PPRE and a decrease of the corresponding mRNA levels. In the same way, treatment of calvarial osteoblasts with GW0742 increased in peroxisome number and

A ketogenic diet rescues hippocampal memory defects in a mouse model of Kabuki syndrome.

Science.gov (United States)

Benjamin, Joel S; Pilarowski, Genay O; Carosso, Giovanni A; Zhang, Li; Huso, David L; Goff, Loyal A; Vernon, Hilary J; Hansen, Kasper D; Bjornsson, Hans T

2017-01-03

Kabuki syndrome is a Mendelian intellectual disability syndrome caused by mutations in either of two genes (KMT2D and KDM6A) involved in chromatin accessibility. We previously showed that an agent that promotes chromatin opening, the histone deacetylase inhibitor (HDACi) AR-42, ameliorates the deficiency of adult neurogenesis in the granule cell layer of the dentate gyrus and rescues hippocampal memory defects in a mouse model of Kabuki syndrome (Kmt2d +/βGeo ). Unlike a drug, a dietary intervention could be quickly transitioned to the clinic. Therefore, we have explored whether treatment with a ketogenic diet could lead to a similar rescue through increased amounts of beta-hydroxybutyrate, an endogenous HDACi. Here, we report that a ketogenic diet in Kmt2d +/βGeo mice modulates H3ac and H3K4me3 in the granule cell layer, with concomitant rescue of both the neurogenesis defect and hippocampal memory abnormalities seen in Kmt2d +/βGeo mice; similar effects on neurogenesis were observed on exogenous administration of beta-hydroxybutyrate. These data suggest that dietary modulation of epigenetic modifications through elevation of beta-hydroxybutyrate may provide a feasible strategy to treat the intellectual disability seen in Kabuki syndrome and related disorders.

Stimulatory effect of undecylenic acid on mouse osteoblast differentiation.

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Kim, Myung Hee; Shim, Ki Shuk; Lee, Su-Ui; Kim, Young Sup; Min, Yong Ki; Kim, Seong Hwan

2010-04-01

Natural compounds with bone-forming (or anabolic) activity have been recently focused on in bone research. The present study investigated the effect of undecylenic acid (UA) on osteoblast differentiation in mouse osteoblastic MC3T3-E1 subclone 4 cells and primary mouse calvarial cells. Low concentrations of UA (up to 5 microM) exhibited no cytotoxicity and significantly increased the expression and activity of alkaline phosphatase (early differentiation marker of osteoblast) and calcium deposition with the induction of expression of the osteocalcin gene in both cells. Interestingly, at low concentration of UA, the induction of NF-kappaB p65 translocation into nucleus and the up-regulation of AP-1 and NFATc1 transcript levels were also observed, suggesting that the stimulatory effect of UA on osteoblast differentiation could be mediated through the activation of transcription factors. Additionally, although the patterns of UA-induced activation of MAP kinases (JNK and p38) were not completely consistent with the increase of both ALP activity and calcium deposition by UA, MAP kinases might be partially involved in the biological function of UA during the early and late stages of osteoblast differentiation. Copyright (c) 2009 John Wiley & Sons, Ltd.

Computed tomographic analysis of calvarial hyperostosis in captive lions.

Science.gov (United States)

Gross-Tsubery, Ruth; Chai, Orit; Shilo, Yael; Miara, Limor; Horowitz, Igal H; Shmueli, Ayelet; Aizenberg, Itzhak; Hoffman, Chen; Reifen, Ram; Shamir, Merav H

2010-01-01

Osseous malformations in the skull and cervical vertebrae of lions in captivity are believed to be caused by hypovitaminosis A. These often lead to severe neurologic abnormalities and may result in death. We describe the characterization of these abnormalities based on computed tomography (CT). CT images of two affected and three healthy lions were compared with define the normal anatomy of the skull and cervical vertebrae and provide information regarding the aforementioned osseous malformations. Because bone structure is influenced by various factors other than the aforementioned disease, all values were divided by the skull width that was not affected. The calculated ratios were compared and the most pronounced abnormalities in the affected lions were, narrowing of the foramen magnum, thickening of the tentorium osseus cerebelli and thickening of the dorsal arch of the atlas. CT is useful for detection of the calvarial abnormalities in lions and may be useful in further defining this syndrome.

Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation.

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Xiaoshan Zhou

Full Text Available Thymidine kinase 2 (TK2 deficiency in humans causes mitochondrial DNA (mtDNA depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/- that progressively loses its mtDNA. The TK2(-/- mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/- mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/- mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/- mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/- mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.

Thymidine kinase 2 deficiency-induced mtDNA depletion in mouse liver leads to defect β-oxidation.

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Zhou, Xiaoshan; Kannisto, Kristina; Curbo, Sophie; von Döbeln, Ulrika; Hultenby, Kjell; Isetun, Sindra; Gåfvels, Mats; Karlsson, Anna

2013-01-01

Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/-)) that progressively loses its mtDNA. The TK2(-/-) mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/-) mouse model to clarify the pathological role of progressive mtDNA depletion in liver for the severe outcome of TK2 deficiency. We observed that a gradual depletion of mtDNA in the liver of the TK2(-/-) mice was accompanied by increasingly hypertrophic mitochondria and accumulation of fat vesicles in the liver cells. The levels of cholesterol and nonesterified fatty acids were elevated and there was accumulation of long chain acylcarnitines in plasma of the TK2(-/-) mice. In mice with hepatic mtDNA levels below 20%, the blood sugar and the ketone levels dropped. These mice also exhibited reduced mitochondrial β-oxidation due to decreased transport of long chain acylcarnitines into the mitochondria. The gradual loss of mtDNA in the liver of the TK2(-/-) mice causes impaired mitochondrial function that leads to defect β-oxidation and, as a result, insufficient production of ketone bodies and glucose. This study provides insight into the mechanism of encephalomyopathy caused by TK2 deficiency-induced mtDNA depletion that may be used to explore novel therapeutic strategies.

Bone tissue engineering with a collagen–hydroxyapatite scaffold and culture expanded bone marrow stromal cells

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Villa, Max M.; Wang, Liping; Huang, Jianping; Rowe, David W.; Wei, Mei

2015-01-01

Osteoprogenitor cells combined with supportive biomaterials represent a promising approach to advance the standard of care for bone grafting procedures. However, this approach faces challenges, including inconsistent bone formation, cell survival in the implant, and appropriate biomaterial degradation. We have developed a collagen–hydroxyapatite (HA) scaffold that supports consistent osteogenesis by donor derived osteoprogenitors, and is more easily degraded than a pure ceramic scaffold. Herein, the material properties are characterized as well as cell attachment, viability, and progenitor distribution in vitro. Furthermore, we examined the biological performance in vivo in a critical-size mouse calvarial defect. To aid in the evaluation of the in-house collagen–HA scaffold, the in vivo performance was compared with a commercial collagen–HA scaffold (Healos®, Depuy). The in-house collagen–HA scaffold supported consistent bone formation by predominantly donor-derived osteoblasts, nearly completely filling a 3.5 mm calvarial defect with bone in all samples (n=5) after 3 weeks of implantation. In terms of bone formation and donor cell retention at 3 weeks postimplantation, no statistical difference was found between the in-house and commercial scaffold following quantitative histomorphometry. The collagen–HA scaffold presented here is an open and well-defined platform that supports robust bone formation and should facilitate the further development of collagen–hydroxyapatite biomaterials for bone tissue engineering. PMID:24909953

Revascularization of calvarial, mandibular, tibial, and iliac bone grafts in rats

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Pinholt, E M; Solheim, E; Talsnes, O

1994-01-01

Some studies have suggested that membranous bone grafts undergo less resorption than endochondral grafts, and faster revascularization of the former has been proposed as the explanation. We studied fresh syngeneic full-thickness bone grafts from calvaria, mandibula, tibia diaphysis, and iliac bone...... implanted in the back muscles of young Lewis rats. As a measure of the quantity of cancellous bone in grafts before implantation, the ratio of the total area of soft-tissue spaces to the total area of the graft was measured histomorphometrically. Revascularization in grafts 3 weeks postoperatively...... was evaluated by deposit of 141Ce-labeled microspheres. Both the quantity of cancellous bone (before implantation) and the revascularization (3 weeks postoperatively) were greater in the mandibular and iliac bone grafts than in the calvarial and tibia diaphyseal grafts. The results suggest that the anatomical...

Defining the molecular pathologies in cloaca malformation: similarities between mouse and human

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Laura A. Runck

2014-04-01

Full Text Available Anorectal malformations are congenital anomalies that form a spectrum of disorders, from the most benign type with excellent functional prognosis, to very complex, such as cloaca malformation in females in which the rectum, vagina and urethra fail to develop separately and instead drain via a single common channel into the perineum. The severity of this phenotype suggests that the defect occurs in the early stages of embryonic development of the organs derived from the cloaca. Owing to the inability to directly investigate human embryonic cloaca development, current research has relied on the use of mouse models of anorectal malformations. However, even studies of mouse embryos lack analysis of the earliest stages of cloaca patterning and morphogenesis. Here we compared human and mouse cloaca development and retrospectively identified that early mis-patterning of the embryonic cloaca might underlie the most severe forms of anorectal malformation in humans. In mouse, we identified that defective sonic hedgehog (Shh signaling results in early dorsal-ventral epithelial abnormalities prior to the reported defects in septation. This is manifested by the absence of Sox2 and aberrant expression of keratins in the embryonic cloaca of Shh knockout mice. Shh knockout embryos additionally develop a hypervascular stroma, which is defective in BMP signaling. These epithelial and stromal defects persist later, creating an indeterminate epithelium with molecular alterations in the common channel. We then used these animals to perform a broad comparison with patients with mild-to-severe forms of anorectal malformations including cloaca malformation. We found striking parallels with the Shh mouse model, including nearly identical defective molecular identity of the epithelium and surrounding stroma. Our work strongly suggests that early embryonic cloacal epithelial differentiation defects might be the underlying cause of severe forms of anorectal malformations

Overexpression of galectin-7 in mouse epidermis leads to loss of cell junctions and defective skin repair.

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Gaëlle Gendronneau

Full Text Available The proteins of the galectin family are implicated in many cellular processes, including cell interactions, polarity, intracellular trafficking, and signal transduction. In human and mouse, galectin-7 is almost exclusively expressed in stratified epithelia, notably in the epidermis. Galectin-7 expression is also altered in several human tumors of epithelial origin. This study aimed at dissecting the consequences of galectin-7 overexpression on epidermis structure and functions in vivo.We established transgenic mice specifically overexpressing galectin-7 in the basal epidermal keratinocytes and analyzed the consequences on untreated skin and after UVB irradiation or mechanical injury.The intercellular cohesion of the epidermis is impaired in transgenic animals, with gaps developing between adjacent keratinocytes, associated with loss of adherens junctions. The epidermal architecture is aberrant with perturbations in the multilayered cellular organisation of the tissue, and structural defects in the basement membrane. These transgenic animals displayed a reduced re-epithelialisation potential following superficial wound, due to a defective collective migration of keratinocytes. Finally, a single mild dose of UVB induced an abnormal apoptotic response in the transgenic epidermis.These results indicate that an excess of galectin-7 leads to a destabilisation of adherens junctions associated with defects in epidermal repair. As this phenotype shares similarities with that of galectin-7 null mutant mice, we conclude that a critical level of this protein is required for maintaining proper epidermal homeostasis. This study brings new insight into the mode of action of galectins in normal and pathological situations.

Selective isolation and differentiation of a stromal population of human embryonic stem cells with osteogenic potential

DEFF Research Database (Denmark)

Harkness, Linda M; Mahmood, Amer; Ditzel, Nicholas

2011-01-01

cultured in osteogenic differentiation media, up regulation of osteoblastic lineage markers (DLX5, MSX2, RUNX2, SPARC, ALP, COL1a1, BGLAP, IBSP, DCN, LOX-L4) and production of in vitro mineralized matrix was detected. hESC-stromal cells loaded on a carrier and implanted either subcutaneously...... or in a critical size calvarial defect in immune deficient mice for 10weeks, resulted in new bone formation and partial repair of the calvarial defect. In conclusion, hESC-stromal can be isolated from hESC cultures and represent a good source for obtaining cells with osteogenic differentiation potential suitable...

Accounting for cranial vault growth in experimental design.

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Power, Stephanie M; Matic, Damir B; Holdsworth, David W

2014-05-01

Earlier studies have not accounted for continued growth when using the rat calvarial defect model to evaluate bone healing in vivo. The purpose of this study was: 1) to calculate rat cranial vault growth over time; and 2) to determine the effects of accounting for growth on defect healing. Bilateral parietal defects were created in 10 adult Wistar rats. Serial microscopic computerized tomography scans were performed. Bone mineral content (BMC) measured according to standard technique and repeated accounting for cranial growth over time was compared with the use of parametric and nonparametric tests. Cranial vault growth continued through 22 weeks of age, increasing 7.5% in width and 9.1% in length, and calvarial defects expanded proportionately. BMC was greater within defects accounting for growth 2-12 weeks postoperatively (P accounting for cranial growth given advances in serial imaging techniques. Crown Copyright © 2014. Published by Mosby, Inc. All rights reserved.

Three-dimensional poly (ε-caprolactone)/hydroxyapatite/collagen scaffolds incorporating bone marrow mesenchymal stem cells for the repair of bone defects

International Nuclear Information System (INIS)

Qi, Xin; Huang, Yinjun; Zhang, Jieyuan; Cao, Jiaqing; Jin, Xiangyun; Huang, Jinghuan; Li, Xiaolin; Wang, Ting; Han, Dan

2016-01-01

We previously demonstrated that three-dimensional (3D) hydroxyapatite (HAP)-collagen (COL)-coated poly(ε-caprolactone) (PCL) scaffolds (HAP-COL-PCL) possess appropriate nano-structures, surface roughness, and nutrients, providing a favorable environment for osteogenesis. However, the effect of using 3D HAP-COL-PCL scaffolds incorporating BMSCs for the repair of bone defects in rats has been not evaluated. 3D PCL scaffolds coated with HAP, collagen or HAP/COL and incorporating BMSCs were implanted into calvarial defects. At 12 weeks after surgery, the rats were sacrificed and crania were harvested to assess the bone defect repair using microcomputed tomography (micro-CT), histology, immunohistochemistry and sequential fluorescent labeling analysis. 3D micro-CT reconstructed images and quantitative analysis showed that HAP-COL-PCL groups possessed better bone-forming capacity than HAP-PCL groups or COL-PCL groups. Fluorescent labeling analysis revealed the percentage of tetracycline labeling, alizarin red labeling, and calcein labeling in HAP-COL-PCL groups were all greater than in the other two groups (P  <  0.05), and the result was confirmed by immunohistochemical staining and histological analysis of bone regeneration. This study demonstrates that 3D HAP-COL-PCL scaffolds incorporating BMSCs markedly enhance bone regeneration of bone defects in rats. (paper)

Disruption of the 5S RNP-Mdm2 interaction significantly improves the erythroid defect in a mouse model for Diamond-Blackfan anemia.

Science.gov (United States)

Jaako, P; Debnath, S; Olsson, K; Zhang, Y; Flygare, J; Lindström, M S; Bryder, D; Karlsson, S

2015-11-01

Diamond-Blackfan anemia (DBA) is a congenital erythroid hypoplasia caused by haploinsufficiency of genes encoding ribosomal proteins (RPs). Perturbed ribosome biogenesis in DBA has been shown to induce a p53-mediated ribosomal stress response. However, the mechanisms of p53 activation and its relevance for the erythroid defect remain elusive. Previous studies have indicated that activation of p53 is caused by the inhibition of mouse double minute 2 (Mdm2), the main negative regulator of p53, by the 5S ribonucleoprotein particle (RNP). Meanwhile, it is not clear whether this mechanism solely mediates the p53-dependent component found in DBA. To approach this question, we crossed our mouse model for RPS19-deficient DBA with Mdm2(C305F) knock-in mice that have a disrupted 5S RNP-Mdm2 interaction. Upon induction of the Rps19 deficiency, Mdm2(C305F) reversed the p53 response and improved expansion of hematopoietic progenitors in vitro, and ameliorated the anemia in vivo. Unexpectedly, disruption of the 5S RNP-Mdm2 interaction also led to selective defect in erythropoiesis. Our findings highlight the sensitivity of erythroid progenitor cells to aberrations in p53 homeostasis mediated by the 5S RNP-Mdm2 interaction. Finally, we provide evidence indicating that physiological activation of the 5S RNP-Mdm2-p53 pathway may contribute to functional decline of the hematopoietic system in a cell-autonomous manner over time.

Global developmental gene expression and pathway analysis of normal brain development and mouse models of human neuronal migration defects.

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Tiziano Pramparo

2011-03-01

Full Text Available Heterozygous LIS1 mutations are the most common cause of human lissencephaly, a human neuronal migration defect, and DCX mutations are the most common cause of X-linked lissencephaly. LIS1 is part of a protein complex including NDEL1 and 14-3-3ε that regulates dynein motor function and microtubule dynamics, while DCX stabilizes microtubules and cooperates with LIS1 during neuronal migration and neurogenesis. Targeted gene mutations of Lis1, Dcx, Ywhae (coding for 14-3-3ε, and Ndel1 lead to neuronal migration defects in mouse and provide models of human lissencephaly, as well as aid the study of related neuro-developmental diseases. Here we investigated the developing brain of these four mutants and wild-type mice using expression microarrays, bioinformatic analyses, and in vivo/in vitro experiments to address whether mutations in different members of the LIS1 neuronal migration complex lead to similar and/or distinct global gene expression alterations. Consistent with the overall successful development of the mutant brains, unsupervised clustering and co-expression analysis suggested that cell cycle and synaptogenesis genes are similarly expressed and co-regulated in WT and mutant brains in a time-dependent fashion. By contrast, focused co-expression analysis in the Lis1 and Ndel1 mutants uncovered substantial differences in the correlation among pathways. Differential expression analysis revealed that cell cycle, cell adhesion, and cytoskeleton organization pathways are commonly altered in all mutants, while synaptogenesis, cell morphology, and inflammation/immune response are specifically altered in one or more mutants. We found several commonly dysregulated genes located within pathogenic deletion/duplication regions, which represent novel candidates of human mental retardation and neurocognitive disabilities. Our analysis suggests that gene expression and pathway analysis in mouse models of a similar disorder or within a common pathway can

Matrix metalloproteinases (MMPs) safeguard osteoblasts from apoptosis during transdifferentiation into osteocytes

DEFF Research Database (Denmark)

Karsdal, M A; Levin Andersen, Thomas; Bonewald, L

2004-01-01

of osteoblasts forced to transdifferentiate into osteocytes in 3D type I collagen gels were inhibited by more than 50% when exposed to 10 microM GM6001 and to Tissue Inhibitor of Metalloproteinase-2 (TIMP-2), a natural MT1-MMP inhibitor. This shows the importance of MMPs in safeguarding osteoblasts from......Osteoblasts undergo apoptosis or differentiate into either osteocytes or bone-lining cells after termination of bone matrix synthesis. In this study, we investigated the role of matrix metalloproteinases (MMPs) in differentiation of osteoblasts, bone formation, transdifferentiation into osteocytes......, and osteocyte apoptosis. This was accomplished by using calvarial sections from the MT1-MMP-deficient mouse and by culture of the mouse osteoblast cell line MC3T3-E1 and primary mouse calvarial osteoblasts. We found that a synthetic matrix metalloprotease inhibitor, GM6001, strongly inhibited bone formation...

Long-term consequences of developmental vascular defects on retinal vessel homeostasis and function in a mouse model of Norrie disease.

Science.gov (United States)

Beck, Susanne C; Feng, Yuxi; Sothilingam, Vithiyanjali; Garcia Garrido, Marina; Tanimoto, Naoyuki; Acar, Niyazi; Shan, Shenliang; Seebauer, Britta; Berger, Wolfgang; Hammes, Hans-Peter; Seeliger, Mathias W

2017-01-01

Loss of Norrin signalling due to mutations in the Norrie disease pseudoglioma gene causes severe vascular defects in the retina, leading to visual impairment and ultimately blindness. While the emphasis of experimental work so far was on the developmental period, we focus here on disease mechanisms that induce progression into severe adult disease. The goal of this study was the comprehensive analysis of the long-term effects of the absence of Norrin on vascular homeostasis and retinal function. In a mouse model of Norrie disease retinal vascular morphology and integrity were studied by means of in vivo angiography; the vascular constituents were assessed in detailed histological analyses using quantitative retinal morphometry. Finally, electroretinographic analyses were performed to assess the retinal function in adult Norrin deficient animals. We could show that the primary developmental defects not only persisted but developed into further vascular abnormalities and microangiopathies. In particular, the overall vessel homeostasis, the vascular integrity, and also the cellular constituents of the vascular wall were affected in the adult Norrin deficient retina. Moreover, functional analyses indicated to persistent hypoxia in the neural retina which was suggested as one of the major driving forces of disease progression. In summary, our data provide evidence that the key to adult Norrie disease are ongoing vascular modifications, driven by the persistent hypoxic conditions, which are ineffective to compensate for the primary Norrin-dependent defects.

Effect of copper-doped silicate 13–93 bioactive glass scaffolds on the response of MC3T3-E1 cells in vitro and on bone regeneration and angiogenesis in rat calvarial defects in vivo

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Lin, Yinan; Xiao, Wei [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Bal, B. Sonny [Department of Orthopaedic Surgery, University of Missouri, Columbia, MO 65212 (United States); Rahaman, Mohamed N., E-mail: rahaman@mst.edu [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States)

2016-10-01

The release of inorganic ions from biomaterials could provide an alternative approach to the use of growth factors for improving tissue healing. In the present study, the release of copper (Cu) ions from bioactive silicate (13–93) glass scaffolds on the response of cells in vitro and on bone regeneration and angiogenesis in vivo was studied. Scaffolds doped with varying concentrations of Cu (0–2.0 wt.% CuO) were created with a grid-like microstructure by robotic deposition. When immersed in simulated body fluid in vitro, the Cu-doped scaffolds released Cu ions into the medium in a dose-dependent manner and converted partially to hydroxyapatite. The proliferation and alkaline phosphatase activity of pre-osteoblastic MC3T3-E1 cells cultured on the scaffolds were not affected by 0.4 and 0.8 wt.% CuO in the glass but they were significantly reduced by 2.0 wt.% CuO. The percent new bone that infiltrated the scaffolds implanted for 6 weeks in rat calvarial defects (46 ± 8%) was not significantly affected by 0.4 or 0.8 wt.% CuO in the glass whereas it was significantly inhibited (0.8 ± 0.7%) in the scaffolds doped with 2.0 wt.% CuO. The area of new blood vessels in the fibrous tissue that infiltrated the scaffolds increased with CuO content of the glass and was significantly higher for the scaffolds doped with 2.0 wt.% CuO. Loading the scaffolds with bone morphogenetic protein-2 (1 μg/defect) significantly enhanced bone infiltration and reduced fibrous tissue in the scaffolds. These results showed that doping the 13–93 glass scaffolds with up to 0.8 wt.% CuO did not affect their biocompatibility whereas 2.0 wt.% CuO was toxic to cells and detrimental to bone regeneration. - Highlights: • First study to evaluate Cu ion release from silicate (13-93) bioactive glass scaffolds on osteogenesis in vivo • Released Cu ions influenced bone regeneration in a dose dependent manner • Lower concentrations of Cu ions had little effect on bone regeneration • Cu ion

Effect of copper-doped silicate 13–93 bioactive glass scaffolds on the response of MC3T3-E1 cells in vitro and on bone regeneration and angiogenesis in rat calvarial defects in vivo

International Nuclear Information System (INIS)

Lin, Yinan; Xiao, Wei; Bal, B. Sonny; Rahaman, Mohamed N.

2016-01-01

The release of inorganic ions from biomaterials could provide an alternative approach to the use of growth factors for improving tissue healing. In the present study, the release of copper (Cu) ions from bioactive silicate (13–93) glass scaffolds on the response of cells in vitro and on bone regeneration and angiogenesis in vivo was studied. Scaffolds doped with varying concentrations of Cu (0–2.0 wt.% CuO) were created with a grid-like microstructure by robotic deposition. When immersed in simulated body fluid in vitro, the Cu-doped scaffolds released Cu ions into the medium in a dose-dependent manner and converted partially to hydroxyapatite. The proliferation and alkaline phosphatase activity of pre-osteoblastic MC3T3-E1 cells cultured on the scaffolds were not affected by 0.4 and 0.8 wt.% CuO in the glass but they were significantly reduced by 2.0 wt.% CuO. The percent new bone that infiltrated the scaffolds implanted for 6 weeks in rat calvarial defects (46 ± 8%) was not significantly affected by 0.4 or 0.8 wt.% CuO in the glass whereas it was significantly inhibited (0.8 ± 0.7%) in the scaffolds doped with 2.0 wt.% CuO. The area of new blood vessels in the fibrous tissue that infiltrated the scaffolds increased with CuO content of the glass and was significantly higher for the scaffolds doped with 2.0 wt.% CuO. Loading the scaffolds with bone morphogenetic protein-2 (1 μg/defect) significantly enhanced bone infiltration and reduced fibrous tissue in the scaffolds. These results showed that doping the 13–93 glass scaffolds with up to 0.8 wt.% CuO did not affect their biocompatibility whereas 2.0 wt.% CuO was toxic to cells and detrimental to bone regeneration. - Highlights: • First study to evaluate Cu ion release from silicate (13-93) bioactive glass scaffolds on osteogenesis in vivo • Released Cu ions influenced bone regeneration in a dose dependent manner • Lower concentrations of Cu ions had little effect on bone regeneration • Cu ion

[Clinical and ossification outcome of custom-made hydroxyapatite prothese for large skull defect].

Science.gov (United States)

Hardy, H; Tollard, E; Derrey, S; Delcampe, P; Péron, J-M; Fréger, P; Proust, F

2012-02-01

Cranioplasty is an everyday concern in neurosurgery, especially in decompressive craniectomy cases. Our surgical team uses custom-made hydroxyapatite implants for large and/or complex defects. Eight patients had a custom-made prosthesis. Each of them has been reviewed by an independent observer. Each patient described his feeling of satisfaction, using a questionnaire, graduated from "A" (really satisfied) to "D" (unsatisfied). Each of them also underwent a CT-scan (helicoidal acquisition, 0.6mm thick for multiplanar reconstruction) to evaluate qualitatively the ossification graduated from "0" (no ossification) to "5" (continuous ossification). Maximal under-prosthetic bone thickness, intra-prosthetic calcic density were also reported. Supervision delay was 43.7 months [6-99 months], average defect surface was 85.5 cm(2) [27.6-137.6 cm(2)], the craniectomy etiologies were intracranial hypertension (seven patients) and calvarial invasion (one patient). Implant tolerance was reparted in "A" score (50%) and "B" score (50%). Concerning ossification, six patients (75%) had a score of "2" or less and two patients had a score of "3" or "4". Hydroxyapatite custom-made implants for cranioplasty appear to be ideal for good aesthetic and tolerance results, but their ossification is hardly analyzed due to the prosthesis density higher than the bone's density. This is why we recommend them for children and in cases of complex defects such as pterion location. Copyright © 2011. Published by Elsevier Masson SAS.

Microarray gene expression during early healing of GBR-treated calvarial critical size defects.

Science.gov (United States)

Al-Kattan, R; Retzepi, M; Calciolari, E; Donos, N

2017-10-01

To investigate the gene expression and molecular pathways implicated in the regulation of the osseous healing process following guided bone regeneration (GBR). Six 6-month-old Wistar male rats were used. Standardized 5-mm critical size defects were created in the parietal bones of each animal and treated with an extracranial and intracranial ePTFE membrane, according to the GBR principle. Three animals were randomly sacrificed after 7 and 15 days of healing. Total RNA was extracted from each sample and prepared for gene expression analysis. RNA quality and quantity were assessed, followed by hybridization of the cRNA to Affymetrix GeneChip Rat Genome 230 2.0 Arrays. The Affymetrix data were processed, and first-order analysis, quality control and statistical analysis were performed. Biological interpretation was performed via pathway and Gene Ontology (GO) analysis. Between the 7- and 15-day samples, 538 genes were differently regulated. At day 7, inflammatory and immune responses were clearly upregulated. In addition, GO terms related to angiogenesis and cell cycle regulation were overexpressed. At day 15, a more complex cellular activity and cell metabolism were evident. The bone formation processes were significantly overexpressed, with several genes encoding growth factors, enzyme activity, and extracellular matrix formation found as upregulated. Remarkably, a negative regulation of Wnt signalling pathway was observed at 15 days. The gene expression profile of the cells participating in osseous formation varied depending on the healing stage. A number of candidate genes that seem differentially expressed during early stages of intramembranous bone regeneration was suggested. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Both nuclear and cytoplasmic components are defective in oocytes of the B6.Y(TIR) sex-reversed female mouse.

Science.gov (United States)

Amleh, A; Smith, L; Chen, H; Taketo, T

2000-03-15

In the mammalian gonadal primordium, activation of the Sry gene on the Y chromosome initiates a cascade of genetic events leading to testicular organization whereas its absence results in ovarian differentiation. An exception occurs when the Y chromosome of Mus musculus domesticus from Tirano, Italy (Y(TIR)), is placed on the C57BL/6J (B6) genetic background. The B6.Y(TIR) progeny develop only ovaries or ovotestes despite Sry transcription in fetal life. Consequently, the XY offspring with bilateral ovaries develop into apparently normal females, but their eggs fail to develop after fertilization. Our previous studies have shown that the primary cause of infertility can be attributed to oocytes rather than their surrounding somatic cells in the XY ovary. This study attempted to identify the defects in oocytes from the B6.Y(TIR) female mouse. We examined the developmental potential of embryos from XY and XX females after exchanging their nuclear components by microsurgery following in vitro maturation and fertilization. The results suggest that both nuclear and cytoplasmic components are defective in oocytes from XY females. In the XY fetal ovary, most germ cells entered meiosis and their autosomes appeared to synapse normally while the X and Y chromosomes remained unpaired during meiotic prophase. This lack of X-Y pairing probably caused aneuploidy in some secondary oocytes following in vitro maturation. However, normal numbers of chromosomes in the rest of the secondary oocytes indicate that aneuploidy alone can not explain the nuclear defect in oocytes. Copyright 2000 Academic Press.

Long-term consequences of developmental vascular defects on retinal vessel homeostasis and function in a mouse model of Norrie disease.

Directory of Open Access Journals (Sweden)

Susanne C Beck

Full Text Available Loss of Norrin signalling due to mutations in the Norrie disease pseudoglioma gene causes severe vascular defects in the retina, leading to visual impairment and ultimately blindness. While the emphasis of experimental work so far was on the developmental period, we focus here on disease mechanisms that induce progression into severe adult disease. The goal of this study was the comprehensive analysis of the long-term effects of the absence of Norrin on vascular homeostasis and retinal function. In a mouse model of Norrie disease retinal vascular morphology and integrity were studied by means of in vivo angiography; the vascular constituents were assessed in detailed histological analyses using quantitative retinal morphometry. Finally, electroretinographic analyses were performed to assess the retinal function in adult Norrin deficient animals. We could show that the primary developmental defects not only persisted but developed into further vascular abnormalities and microangiopathies. In particular, the overall vessel homeostasis, the vascular integrity, and also the cellular constituents of the vascular wall were affected in the adult Norrin deficient retina. Moreover, functional analyses indicated to persistent hypoxia in the neural retina which was suggested as one of the major driving forces of disease progression. In summary, our data provide evidence that the key to adult Norrie disease are ongoing vascular modifications, driven by the persistent hypoxic conditions, which are ineffective to compensate for the primary Norrin-dependent defects.

Safe Harvesting of Outer Table Parietal Bone Grafts Using an Oscillating Saw and a Bone Scraper : A Refinement of Technique for Harvesting Cortical and "Cancellous"-Like Calvarial Bone

NARCIS (Netherlands)

Schortinghuis, Jurjen; Putters, Thomas F.; Raghoebar, Gerry M.

Calvarial bone is a readily available source of bone for preimplantation augmentation procedures of the alveolar process. However, the calvaria consist mostly of cortical bone, and cancellous bone of the diploic space is scarce. A bone scraper (Safescraper Twist; META, Reggio Emilia, Italy) was used

Defective immuno- and thymoproteasome assembly causes severe immunodeficiency

DEFF Research Database (Denmark)

Treise, Irina; Huber, Eva M.; Klein-Rodewald, Tanja

2018-01-01

By N-ethyl-N-nitrosourea (ENU) mutagenesis, we generated the mutant mouse line TUB6 that is characterised by severe combined immunodeficiency (SCID) and systemic sterile autoinflammation in homozygotes, and a selective T cell defect in heterozygotes. The causative missense point mutation results...

Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

International Nuclear Information System (INIS)

Chen, Szu-Hsien; Tsao, Ching-Ting; Chang, Chih-Hao; Lai, Yi-Ting; Wu, Ming-Fung; Chuang, Ching-Nan; Chou, Hung-Chia; Wang, Chih-Kuang; Hsieh, Kuo-Haung

2013-01-01

Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m 2 /day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing. Highlights: ► Mouse angiogenesis study on reinforced poly(ethylene glycol)-chitosan (RPC) ► Water vapor transmission rate of about 2000 g/m 2 /day is characteristic of RPC. ► RPC suppressed inflammatory cells and accelerated fibroblast proliferation. ► RPC composed of 1000-RP10C90 can be used as a biomaterial for wound dressing

Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

Energy Technology Data Exchange (ETDEWEB)

Chen, Szu-Hsien [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Tsao, Ching-Ting [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Epithelial Biology Laboratory/Transgenic Mice Core-Laboratory, Department of Anatomy, Chang Gung University, Taoyuan 33302, Taiwan (China); Chang, Chih-Hao [Department of Orthopedics, National Taiwan University Hospital, Taiwan (China); National Taiwan University College of Medicine, No. 1, Jen-Ai Road, Taipei City 10018, Taiwan (China); Lai, Yi-Ting [Department of Chemical Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Wu, Ming-Fung [Animal Medicine Center, College of Medicine, National Taiwan University, No. 1, Jen-Ai Road, Taipei City 10018, Taiwan (China); Chuang, Ching-Nan [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Chou, Hung-Chia [Department of Chemical Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Wang, Chih-Kuang, E-mail: ckwang@kmu.edu.tw [Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Hsieh, Kuo-Haung, E-mail: khhsieh@ntu.edu.tw [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China)

2013-07-01

Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m{sup 2}/day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing. Highlights: ► Mouse angiogenesis study on reinforced poly(ethylene glycol)-chitosan (RPC) ► Water vapor transmission rate of about 2000 g/m{sup 2}/day is characteristic of RPC. ► RPC suppressed inflammatory cells and accelerated fibroblast proliferation. ► RPC composed of 1000-RP10C90 can be used as a biomaterial for wound dressing.

Recovery of deficient homologous recombination in Brca2-depleted mouse cells by wild-type Rad51 expression.

Science.gov (United States)

Lee, Shauna A; Roques, Céline; Magwood, Alissa C; Masson, Jean-Yves; Baker, Mark D

2009-02-01

The BRCA2 tumor suppressor is important in maintaining genomic stability. BRCA2 is proposed to control the availability, cellular localization and DNA binding activity of the central homologous recombination protein, RAD51, with loss of BRCA2 resulting in defective homologous recombination. Nevertheless, the roles of BRCA2 in regulating RAD51 and how other proteins implicated in RAD51 regulation, such as RAD52 and RAD54 function relative to BRCA2 is not known. In this study, we tested whether defective homologous recombination in Brca2-depleted mouse hybridoma cells could be rectified by expression of mouse Rad51 or the Rad51-interacting mouse proteins, Rad52 and Rad54. In the Brca2-depleted cells, defective homologous recombination can be restored by over-expression of wild-type mouse Rad51, but not mouse Rad52 or Rad54. Correction of the homologous recombination defect requires Rad51 ATPase activity. A sizeable fraction ( approximately 50%) of over-expressed wild-type Rad51 is nuclear localized. The restoration of homologous recombination in the presence of a low (i.e., non-functional) level of Brca2 by wild-type Rad51 over-expression is unexpected. We suggest that Rad51 may access the nuclear compartment in a Brca2-independent manner and when Rad51 is over-expressed, the normal requirement for Brca2 control over Rad51 function in homologous recombination is dispensable. Our studies support loss of Rad51 function as a critical underlying factor in the homologous recombination defect in the Brca2-depleted cells.

Bone matrix calcification during embryonic and postembryonic rat calvarial development assessed by SEM-EDX spectroscopy, XRD, and FTIR spectroscopy.

Science.gov (United States)

Henmi, Akiko; Okata, Hiroshi; Anada, Takahisa; Yoshinari, Mariko; Mikami, Yasuto; Suzuki, Osamu; Sasano, Yasuyuki

2016-01-01

Bone mineral is constituted of biological hydroxyapatite crystals. In developing bone, the mineral crystal matures and the Ca/P ratio increases. However, how an increase in the Ca/P ratio is involved in maturation of the crystal is not known. The relationships among organic components and mineral changes are also unclear. The study was designed to investigate the process of calcification during rat calvarial bone development. Calcification was evaluated by analyzing the atomic distribution and concentration of Ca, P, and C with scanning electron microscopy (SEM)-energy-dispersive X-ray (EDX) spectroscopy and changes in the crystal structure with X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Histological analysis showed that rat calvarial bone formation started around embryonic day 16. The areas of Ca and P expanded, matching the region of the developing bone matrix, whereas the area of C became localized around bone. X-ray diffraction and FTIR analysis showed that the amorphous-like structure of the minerals at embryonic day 16 gradually transformed into poorly crystalline hydroxyapatite, whereas the proportion of mineral to protein increased until postnatal week 6. FTIR analysis also showed that crystallization of hydroxyapatite started around embryonic day 20, by which time SEM-EDX spectroscopy showed that the Ca/P ratio had increased and the C/Ca and C/P ratios had decreased significantly. The study suggests that the Ca/P molar ratio increases and the proportion of organic components such as proteins of the bone matrix decreases during the early stage of calcification, whereas crystal maturation continues throughout embryonic and postembryonic bone development.

Dietary arginine silicate inositol complex increased bone healing: histologic and histomorphometric study

Directory of Open Access Journals (Sweden)

Yaman F

2016-06-01

Full Text Available Ferhan Yaman,1 Izzet Acikan,1 Serkan Dundar,2 Sercan Simsek,3 Mehmet Gul,4 İbrahim Hanifi Ozercan,3 James Komorowski,5 Kazim Sahin6 1Department of Oral-Maxillofacial Surgery, Faculty of Dentistry, Dicle University, Diyarbakir, Turkey; 2Department of Periodontology, Faculty of Dentistry, Firat University, Elazig, Turkey; 3Department of Pathology, Faculty of Medicine, Firat University, Elazig, Turkey; 4Department of Periodontology, Faculty of Dentistry, Dicle University, Diyarbakir, Turkey; 5Nutrition 21, LLC, Purchase, NY, USA; 6Department of Animal Nutrition, Faculty of Veterinary Medicine, Firat University, Elazig, Turkey Background: Arginine silicate inositol complex (ASI; arginine 49.5%, silicon 8.2%, and inositol 25% is a novel material that is a bioavailable source of silicon and arginine. ASI offers potential benefits for vascular and bone health. Objective: The aim of this study was to evaluate the potential effects of ASI complex on bone healing of critical-sized defects in rats. Methods: The rats were randomly assigned to two groups of 21 rats each. The control group was fed a standard diet for 12 weeks; after the first 8 weeks, a calvarial critical-sized defect was created, and the rats were sacrificed 7, 14, and 28 days later. The ASI group was fed a diet containing 1.81 g/kg of ASI for 12 weeks; after the first 8 weeks, a calvarial critical-sized defect was created, and the rats were sacrificed 7, 14, and 28 days later. The calvarial bones of all the rats were then harvested for evaluation. Results: Osteoblasts and osteoclasts were detected at higher levels in the ASI group compared with the control group at days 7, 14, and 28 of the calvarial defect (P<0.05. New bone formation was detected at higher levels in the ASI group compared with the controls at day 28 (P<0.05. However, new bone formation was not detected at days 7 and 14 in both the groups (P>0.05. Conclusion: ASI supplementation significantly improved bone tissue

Ultrasonography of Midline Scalp Masses : A Preliminary Report

Energy Technology Data Exchange (ETDEWEB)

Choi, Hyo Kyeong; Lee, Ho Kyu; Choi, Choong Gon; Kim, Kyeong Sook; Jung, Seung Mun; Suh, Dae Chul [Asan Medical Center University of Ulsan College of Medicine, Seoul (Korea, Republic of)

1995-06-15

We report our ultrasonographic experiences in the evaluation of small midline scalp masses. Ultrasonography was performed in four patients with midline scalp mass less than 3cm and its connecting tract into the cranialcavity. Ultrasonographic findings were correlated with pathologic results. There were three cephaloceles and one cystic lymph angioma. Two encephalomenin-goceles, located in occipital region, were mixed cystic and solid lesions and one atretic meningocele in parietal region was a solid lesion. Ultrasonogram of all three cases showed calvarial defect and connecting tract into the cranial cavity. On the contrary, a cystic lymph angioma in occipital region was a purely cystic mass without an associated calvarial defect. We suppose that ultrasonography could be a useful screening tool in the evaluation of midline scalp masses

Mouse Models for Investigating the Developmental Bases of Human Birth Defects

OpenAIRE

MOON, ANNE M.

2006-01-01

Clinicians and basic scientists share an interest in discovering how genetic or environmental factors interact to perturb normal development and cause birth defects and human disease. Given the complexity of such interactions, it is not surprising that 4% of human infants are born with a congenital malformation, and cardiovascular defects occur in nearly 1%. Our research is based on the fundamental hypothesis that an understanding of normal and abnormal development will permit us to generate ...

Imaging techniques for visualizing and phenotyping congenital heart defects in murine models.

Science.gov (United States)

Liu, Xiaoqin; Tobita, Kimimasa; Francis, Richard J B; Lo, Cecilia W

2013-06-01

Mouse model is ideal for investigating the genetic and developmental etiology of congenital heart disease. However, cardiovascular phenotyping for the precise diagnosis of structural heart defects in mice remain challenging. With rapid advances in imaging techniques, there are now high throughput phenotyping tools available for the diagnosis of structural heart defects. In this review, we discuss the efficacy of four different imaging modalities for congenital heart disease diagnosis in fetal/neonatal mice, including noninvasive fetal echocardiography, micro-computed tomography (micro-CT), micro-magnetic resonance imaging (micro-MRI), and episcopic fluorescence image capture (EFIC) histopathology. The experience we have gained in the use of these imaging modalities in a large-scale mouse mutagenesis screen have validated their efficacy for congenital heart defect diagnosis in the tiny hearts of fetal and newborn mice. These cutting edge phenotyping tools will be invaluable for furthering our understanding of the developmental etiology of congenital heart disease. Copyright © 2013 Wiley Periodicals, Inc.

Three dimensional printing of calcium sulfate and mesoporous bioactive glass scaffolds for improving bone regeneration in vitro and in vivo

Science.gov (United States)

Qi, Xin; Pei, Peng; Zhu, Min; Du, Xiaoyu; Xin, Chen; Zhao, Shichang; Li, Xiaolin; Zhu, Yufang

2017-02-01

In the clinic, bone defects resulting from infections, trauma, surgical resection and genetic malformations remain a significant challenge. In the field of bone tissue engineering, three-dimensional (3D) scaffolds are promising for the treatment of bone defects. In this study, calcium sulfate hydrate (CSH)/mesoporous bioactive glass (MBG) scaffolds were successfully fabricated using a 3D printing technique, which had a regular and uniform square macroporous structure, high porosity and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on scaffolds to evaluate hBMSC attachment, proliferation and osteogenesis-related gene expression. Critical-sized rat calvarial defects were applied to investigate the effect of CSH/MBG scaffolds on bone regeneration in vivo. The in vitro results showed that CSH/MBG scaffolds stimulated the adhesion, proliferation, alkaline phosphatase (ALP) activity and osteogenesis-related gene expression of hBMSCs. In vivo results showed that CSH/MBG scaffolds could significantly enhance new bone formation in calvarial defects compared to CSH scaffolds. Thus 3D printed CSH/MBG scaffolds would be promising candidates for promoting bone regeneration.

Transplanted Umbilical Cord Mesenchymal Stem Cells Modify the In Vivo Microenvironment Enhancing Angiogenesis and Leading to Bone Regeneration

Science.gov (United States)

Todeschi, Maria Rosa; El Backly, Rania; Capelli, Chiara; Daga, Antonio; Patrone, Eugenio; Introna, Martino; Cancedda, Ranieri

2015-01-01

Umbilical cord mesenchymal stem cells (UC-MSCs) show properties similar to bone marrow mesenchymal stem cells (BM-MSCs), although controversial data exist regarding their osteogenic potential. We prepared clinical-grade UC-MSCs from Wharton's Jelly and we investigated if UC-MSCs could be used as substitutes for BM-MSCs in muscoloskeletal regeneration as a more readily available and functional source of MSCs. UC-MSCs were loaded onto scaffolds and implanted subcutaneously (ectopically) and in critical-sized calvarial defects (orthotopically) in mice. For live cell-tracking experiments, UC-MSCs were first transduced with the luciferase gene. Angiogenic properties of UC-MSCs were tested using the mouse metatarsal angiogenesis assay. Cell secretomes were screened for the presence of various cytokines using an array assay. Analysis of implanted scaffolds showed that UC-MSCs, contrary to BM-MSCs, remained detectable in the implants for 3 weeks at most and did not induce bone formation in an ectopic location. Instead, they induced a significant increase of blood vessel ingrowth. In agreement with these observations, UC-MSC-conditioned medium presented a distinct and stronger proinflammatory/chemotactic cytokine profile than BM-MSCs and a significantly enhanced angiogenic activity. When UC-MSCs were orthotopically transplanted in a calvarial defect, they promoted increased bone formation as well as BM-MSCs. However, at variance with BM-MSCs, the new bone was deposited through the activity of stimulated host cells, highlighting the importance of the microenvironment on determining cell commitment and response. Therefore, we propose, as therapy for bone lesions, the use of allogeneic UC-MSCs by not depositing bone matrix directly, but acting through the activation of endogenous repair mechanisms. PMID:25685989

Enhanced Bone Tissue Regeneration by Porous Gelatin Composites Loaded with the Chinese Herbal Decoction Danggui Buxue Tang.

Directory of Open Access Journals (Sweden)

Wen-Ling Wang

Full Text Available Danggui Buxue Tang (DBT is a traditional Chinese herbal decoction containing Radix Astragali and Radix Angelicae sinensis. Pharmacological results indicate that DBT can stimulate bone cell proliferation and differentiation. The aim of the study was to investigate the efficacy of adding DBT to bone substitutes on bone regeneration following bone injury. DBT was incorporated into porous composites (GGT made from genipin-crosslinked gelatin and β-triclacium phosphates as bone substitutes (GGTDBT. The biological response of mouse calvarial bone to these composites was evaluated by in vivo imaging systems (IVIS, micro-computed tomography (micro-CT, and histology analysis. IVIS images revealed a stronger fluorescent signal in GGTDBT-treated defect than in GGT-treated defect at 8 weeks after implantation. Micro-CT analysis demonstrated that the level of repair from week 4 to 8 increased from 42.1% to 71.2% at the sites treated with GGTDBT, while that increased from 33.2% to 54.1% at GGT-treated sites. These findings suggest that the GGTDBT stimulates the innate regenerative capacity of bone, supporting their use in bone tissue regeneration.

NMDAR NR2A and NR2B specific PKC-dependent regulation of mGluR is defective in the Fragile X Syndrome mouse model

DEFF Research Database (Denmark)

Banke, Tue G.; Toft, Anna Karina; Lundbye, Camilla Johanne

The Fragile X Syndrome (FXS) animal model, the Fmr1 knock-out (KO) mouse, has demonstrated an increased mGluR5-mediated long-term depression (LTD). However, surprisingly little information exists about other ion channels/receptors and their effects on FXS, including NMDA receptors (NMDAR). Here we....... Furthermore, in this model it appears that NR2B activation stimulates PKC, while NR2A activation halts or reverses this effect. In addition, in the KO mice, the coupling between specific NMDAR subunits and mGluR-LTD activity through PKC seems defective in an age-dependent manner. These findings suggest strong...

Palmitate attenuates osteoblast differentiation of fetal rat calvarial cells.

Science.gov (United States)

Yeh, Lee-Chuan C; Ford, Jeffery J; Lee, John C; Adamo, Martin L

2014-07-18

Aging is associated with the accumulation of ectopic lipid resulting in the inhibition of normal organ function, a phenomenon known as lipotoxicity. Within the bone marrow microenvironment, elevation in fatty acid levels may produce an increase in osteoclast activity and a decrease in osteoblast number and function, thus contributing to age-related osteoporosis. However, little is known about lipotoxic mechanisms in intramembraneous bone. Previously we reported that the long chain saturated fatty acid palmitate inhibited the expression of the osteogenic markers RUNX2 and osteocalcin in fetal rat calvarial cell (FRC) cultures. Moreover, the acetyl CoA carboxylase inhibitor TOFA blocked the inhibitory effect of palmitate on expression of these two markers. In the current study we have extended these observations to show that palmitate inhibits spontaneous mineralized bone formation in FRC cultures in association with reduced mRNA expression of RUNX2, alkaline phosphatase, osteocalcin, and bone sialoprotein and reduced alkaline phosphatase activity. The effects of palmitate on osteogenic marker expression were inhibited by TOFA. Palmitate also inhibited the mRNA expression of fatty acid synthase and PPARγ in FRC cultures, and as with osteogenic markers, this effect was inhibited by TOFA. Palmitate had no effect on FRC cell proliferation or apoptosis, but inhibited BMP-7-induced alkaline phosphatase activity. We conclude that palmitate accumulation may lead to lipotoxic effects on osteoblast differentiation and mineralization and that increases in fatty acid oxidation may help to prevent these lipotoxic effects. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of electron-beam irradiation to the hydroxyapatite and tricalcium phosphate mixtures for the development of new synthetic bone substitutes

Energy Technology Data Exchange (ETDEWEB)

Kim, Soung Min; Eo, Mi Young; Kang, Ji Young; Park, Jung Min; Seo, Mi Hyun; Myoung, Hoon; Lee, Jong Ho [Seoul National Univ., Seoul (Korea, Republic of); Han, Young Hwan; Lee, Byung Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2010-07-01

The aim of this study is to evaluate the effect and potential of electron beam irradiation treatment to new bone formation and healing in rat calvarial bone defects using hydroxyapatite and tricalcium phosphate mixtures. We used 1.0-2.0 MeV linear accelerator and 2.0 MeV superconductive linear accelerator with different irradiation dose such as 1, 30, 60 kGy. Structural changes in this synthetic bone material were analyzed in vitro, such as SEM, elementary and FE-SEM, ATR-IR, and CSR. And after sterilization with ethylene oxide, we use it as a bone graft material, in vivo. Bilateral, standardized truenesses circular calvarial defects, 7.0 mm in diameter, were created in male Sprague-Dawley rats. In each experimental group, the defect was filled with electron beam irradiated synthetic bony mixtures. Rate were sacrificed 2, 4 and 8 weeks post-op. for radiographic, histomorphologic, immunohistochemical staining, TEM, and elementary analysis.

Effects of oxidative stress on hyperglycaemia-induced brain malformations in a diabetes mouse model

Energy Technology Data Exchange (ETDEWEB)

Jin, Ya [Department of Pediatrics, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China (China); Wang, Guang [Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632 (China); Han, Sha-Sha; He, Mei-Yao [Department of Pediatrics, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China (China); Cheng, Xin; Ma, Zheng-Lai [Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632 (China); Wu, Xia [Department of Pediatrics, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China (China); Yang, Xuesong, E-mail: yang_xuesong@126.com [Division of Histology & Embryology, Key Laboratory for Regenerative Medicine of the Ministry of Education, Medical College, Jinan University, Guangzhou 510632 (China); Liu, Guo-Sheng, E-mail: tlgs@jnu.edu.cn [Department of Pediatrics, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China (China)

2016-09-10

Pregestational diabetes mellitus (PGDM) enhances the risk of fetal neurodevelopmental defects. However, the mechanism of hyperglycaemia-induced neurodevelopmental defects is not fully understood. In this study, several typical neurodevelopmental defects were identified in the streptozotocin-induced diabetes mouse model. The neuron-specific class III beta-tubulin/forkhead box P1-labelled neuronal differentiation was suppressed and glial fibrillary acidic protein-labelled glial cell lineage differentiation was slightly promoted in pregestational diabetes mellitus (PGDM) mice. Various concentrations of glucose did not change the U87 cell viability, but glial cell line-derived neurotrophic factor expression was altered with varying glucose concentrations. Mouse maternal hyperglycaemia significantly increased Tunel{sup +} apoptosis but did not dramatically affect PCNA{sup +} cell proliferation in the process. To determine the cause of increased apoptosis, we determined the SOD activity, the expression of Nrf2 as well as its downstream anti-oxidative factors NQO1 and HO1, and found that all of them significantly increased in PGDM fetal brains compared with controls. However, Nrf2 expression in U87 cells was not significantly changed by different glucose concentrations. In mouse telencephalon, we observed the co-localization of Tuj-1 and Nrf2 expression in neurons, and down-regulating of Nrf2 in SH-SY5Y cells altered the viability of SH-SY5Y cells exposed to high glucose concentrations. Taken together, the data suggest that Nrf2-modulated antioxidant stress plays a crucial role in maternal hyperglycaemia-induced neurodevelopmental defects. - Highlights: • Typical neurodevelopmental defects could be observed in STZ-treated mouse fetuses. • Nrf2 played a crucial role in hyperglycaemia-induced brain malformations. • The effects of hyperglycaemia on neurons and glia cells were not same.

Effects of oxidative stress on hyperglycaemia-induced brain malformations in a diabetes mouse model

International Nuclear Information System (INIS)

Jin, Ya; Wang, Guang; Han, Sha-Sha; He, Mei-Yao; Cheng, Xin; Ma, Zheng-Lai; Wu, Xia; Yang, Xuesong; Liu, Guo-Sheng

2016-01-01

Pregestational diabetes mellitus (PGDM) enhances the risk of fetal neurodevelopmental defects. However, the mechanism of hyperglycaemia-induced neurodevelopmental defects is not fully understood. In this study, several typical neurodevelopmental defects were identified in the streptozotocin-induced diabetes mouse model. The neuron-specific class III beta-tubulin/forkhead box P1-labelled neuronal differentiation was suppressed and glial fibrillary acidic protein-labelled glial cell lineage differentiation was slightly promoted in pregestational diabetes mellitus (PGDM) mice. Various concentrations of glucose did not change the U87 cell viability, but glial cell line-derived neurotrophic factor expression was altered with varying glucose concentrations. Mouse maternal hyperglycaemia significantly increased Tunel"+ apoptosis but did not dramatically affect PCNA"+ cell proliferation in the process. To determine the cause of increased apoptosis, we determined the SOD activity, the expression of Nrf2 as well as its downstream anti-oxidative factors NQO1 and HO1, and found that all of them significantly increased in PGDM fetal brains compared with controls. However, Nrf2 expression in U87 cells was not significantly changed by different glucose concentrations. In mouse telencephalon, we observed the co-localization of Tuj-1 and Nrf2 expression in neurons, and down-regulating of Nrf2 in SH-SY5Y cells altered the viability of SH-SY5Y cells exposed to high glucose concentrations. Taken together, the data suggest that Nrf2-modulated antioxidant stress plays a crucial role in maternal hyperglycaemia-induced neurodevelopmental defects. - Highlights: • Typical neurodevelopmental defects could be observed in STZ-treated mouse fetuses. • Nrf2 played a crucial role in hyperglycaemia-induced brain malformations. • The effects of hyperglycaemia on neurons and glia cells were not same.

Interleukin-2 stimulates osteoclastic activity: Increased acid production and radioactive calcium release

International Nuclear Information System (INIS)

Ries, W.L.; Seeds, M.C.; Key, L.L.

1989-01-01

Recombinant human interleukin-2 (IL-2) was studied to determine effects on acid production by individual osteoclasts in situ on mouse calvarial bones. This analysis was performed using a microspectrofluorimetric technique to quantify acid production in individual cells. Radioactive calcium release was determined using calvarial bones in a standard tissue culture system. This allowed us to correlate changes in acid production with a measure of bone resorption. IL-2 stimulated acid production and bone resorbing activity. Both effects were inhibited by calcitonin. No stimulation of bone resorption occurred when IL-2-containing test media was incubated with a specific anti-IL-2 antibody and ultrafiltered. Our data demonstrated a correlation between acid production and bone resorbing activity in mouse calvaria exposed to parathyroid hormone (PTH). The data obtained from cultured mouse calvaria exposed to IL-2 demonstrated similar stimulatory effects to those seen during PTH exposure. These data suggest that calvaria exposed to IL-2 in vitro have increased osteoclastic acid production corresponding with increased bone resorption. (author)

Synergistic effects of dimethyloxallyl glycine and recombinant human bone morphogenetic protein-2 on repair of critical-sized bone defects in rats

Science.gov (United States)

Qi, Xin; Liu, Yang; Ding, Zhen-Yu; Cao, Jia-Qing; Huang, Jing-Huan; Zhang, Jie-Yuan; Jia, Wei-Tao; Wang, Jing; Liu, Chang-Sheng; Li, Xiao-Lin

2017-02-01

In bone remodeling, osteogenesis is closely coupled to angiogenesis. Bone tissue engineering using multifunctional bioactive materials is a promising technique which has the ability to simultaneously stimulate osteogenesis and angiogenesis for repair of bone defects. We developed mesoporous bioactive glass (MBG)-doped poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) composite scaffolds as delivery vehicle. Two bioactive molecules, dimethyloxalylglycine (DMOG), a small-molecule angiogenic drug, and recombinant human bone morphogenetic protein-2 (rhBMP-2), an osteoinductive growth factor, were co-incorporated into the scaffold. The synergistic effects of DMOG and rhBMP-2 released in the composite scaffolds on osteogenic and angiogenic differentiation of hBMSCs were investigated using real-time quantitative polymerase chain reaction and western blotting. Moreover, in vivo studies were conducted to observe bone regeneration and vascular formation of critical-sized bone defects in rats using micro-computed tomography, histological analyses, Microfil® perfusion, fluorescence labeling, and immunohistochemical analysis. The results showed that DMOG and rhBMP-2 released in the MBG-PHBHHx scaffolds did exert synergistic effects on the osteogenic and angiogenic differentiation of hBMSCs. Moreover, DMOG and rhBMP-2 produced significant increases in newly-formed bone and neovascularization of calvarial bone defects in rats. It is concluded that the co-delivery strategy of both rhBMP-2 and DMOG can significantly improve the critical-sized bone regeneration.

Mouse models of Fanconi anemia

International Nuclear Information System (INIS)

Parmar, Kalindi; D'Andrea, Alan; Niedernhofer, Laura J.

2009-01-01

Fanconi anemia is a rare inherited disease characterized by congenital anomalies, growth retardation, aplastic anemia and an increased risk of acute myeloid leukemia and squamous cell carcinomas. The disease is caused by mutation in genes encoding proteins required for the Fanconi anemia pathway, a response mechanism to replicative stress, including that caused by genotoxins that cause DNA interstrand crosslinks. Defects in the Fanconi anemia pathway lead to genomic instability and apoptosis of proliferating cells. To date, 13 complementation groups of Fanconi anemia were identified. Five of these genes have been deleted or mutated in the mouse, as well as a sixth key regulatory gene, to create mouse models of Fanconi anemia. This review summarizes the phenotype of each of the Fanconi anemia mouse models and highlights how genetic and interventional studies using the strains have yielded novel insight into therapeutic strategies for Fanconi anemia and into how the Fanconi anemia pathway protects against genomic instability.

Mouse models of Fanconi anemia

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Parmar, Kalindi; D' Andrea, Alan [Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, MA 02115 (United States); Niedernhofer, Laura J., E-mail: niedernhoferl@upmc.edu [Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine and Cancer Institute, 5117 Centre Avenue, Hillman Cancer Center, Research Pavilion 2.6, Pittsburgh, PA 15213-1863 (United States)

2009-07-31

Fanconi anemia is a rare inherited disease characterized by congenital anomalies, growth retardation, aplastic anemia and an increased risk of acute myeloid leukemia and squamous cell carcinomas. The disease is caused by mutation in genes encoding proteins required for the Fanconi anemia pathway, a response mechanism to replicative stress, including that caused by genotoxins that cause DNA interstrand crosslinks. Defects in the Fanconi anemia pathway lead to genomic instability and apoptosis of proliferating cells. To date, 13 complementation groups of Fanconi anemia were identified. Five of these genes have been deleted or mutated in the mouse, as well as a sixth key regulatory gene, to create mouse models of Fanconi anemia. This review summarizes the phenotype of each of the Fanconi anemia mouse models and highlights how genetic and interventional studies using the strains have yielded novel insight into therapeutic strategies for Fanconi anemia and into how the Fanconi anemia pathway protects against genomic instability.

Kidney adysplasia and variable hydronephrosis, a new mutation affecting the odd-skipped related 1 gene in the mouse, causes variable defects in kidney development and hydronephrosis.

Science.gov (United States)

Davisson, Muriel T; Cook, Susan A; Akeson, Ellen C; Liu, Don; Heffner, Caleb; Gudis, Polyxeni; Fairfield, Heather; Murray, Stephen A

2015-06-15

Many genes, including odd-skipped related 1 (Osr1), are involved in regulation of mammalian kidney development. We describe here a new recessive mutation (kidney adysplasia and variable hydronephrosis, kavh) in the mouse that leads to downregulation of Osr1 transcript, causing several kidney defects: agenesis, hypoplasia, and hydronephrosis with variable age of onset. The mutation is closely associated with a reciprocal translocation, T(12;17)4Rk, whose Chromosome 12 breakpoint is upstream from Osr1. The kavh/kavh mutant provides a model to study kidney development and test therapies for hydronephrosis. Copyright © 2015 the American Physiological Society.

Bone regeneration of critical calvarial defect in goat model by PLGA/TCP/rhBMP-2 scaffolds prepared by low-temperature rapid-prototyping technology.

Science.gov (United States)

Yu, D; Li, Q; Mu, X; Chang, T; Xiong, Z

2008-10-01

Active artificial bone composed of poly lactide-co-glycolide (PLGA)/ tricalcium phosphate (TCP) was prefabricated using low-temperature rapid-prototyping technology so that the process of osteogenesis could be observed in it. PLGA and TCP were the primary materials, they were molded at low temperature, then recombinant human bone morphogenetic protein-2 (rhBMP-2) was added to form an active artificial bone. Goats with standard cranial defects were randomly divided into experimental (implants with rhBMP-2 added) and control (implants without rhBMP-2) groups, and osteogenesis was observed and evaluated by imaging and biomechanical and histological examinations. The PLGA-TCP artificial bone scaffold (90% porosity) had large and small pores of approximately 360microm and 3-5microm diameter. Preliminary and complete repair of the cranial defect in the goats occurred 12 and 24 weeks after surgery, respectively. The three-point bending strength of the repaired defects attained that of the normal cranium. In conclusion, low-temperature rapid-prototyping technology can preserve the biological activity of this scaffold material. The scaffold has a good three-dimensional structure and it becomes an active artificial bone after loading with rhBMP-2 with a modest degradation rate and excellent osteogenesis in the goat.

Astrocyte-secreted thrombospondin-1 modulates synapse and spine defects in the fragile X mouse model.

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Cheng, Connie; Lau, Sally K M; Doering, Laurie C

2016-08-02

Astrocytes are key participants in various aspects of brain development and function, many of which are executed via secreted proteins. Defects in astrocyte signaling are implicated in neurodevelopmental disorders characterized by abnormal neural circuitry such as Fragile X syndrome (FXS). In animal models of FXS, the loss in expression of the Fragile X mental retardation 1 protein (FMRP) from astrocytes is associated with delayed dendrite maturation and improper synapse formation; however, the effect of astrocyte-derived factors on the development of neurons is not known. Thrombospondin-1 (TSP-1) is an important astrocyte-secreted protein that is involved in the regulation of spine development and synaptogenesis. In this study, we found that cultured astrocytes isolated from an Fmr1 knockout (Fmr1 KO) mouse model of FXS displayed a significant decrease in TSP-1 protein expression compared to the wildtype (WT) astrocytes. Correspondingly, Fmr1 KO hippocampal neurons exhibited morphological deficits in dendritic spines and alterations in excitatory synapse formation following long-term culture. All spine and synaptic abnormalities were prevented in the presence of either astrocyte-conditioned media or a feeder layer derived from FMRP-expressing astrocytes, or following the application of exogenous TSP-1. Importantly, this work demonstrates the integral role of astrocyte-secreted signals in the establishment of neuronal communication and identifies soluble TSP-1 as a potential therapeutic target for Fragile X syndrome.

Pancreas-specific deletion of mouse Gata4 and Gata6 causes pancreatic agenesis

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Xuan, Shouhong; Borok, Matthew J.; Decker, Kimberly J.; Battle, Michele A.; Duncan, Stephen A.; Hale, Michael A.; Macdonald, Raymond J.; Sussel, Lori

2012-01-01

Pancreatic agenesis is a human disorder caused by defects in pancreas development. To date, only a few genes have been linked to pancreatic agenesis in humans, with mutations in pancreatic and duodenal homeobox 1 (PDX1) and pancreas-specific transcription factor 1a (PTF1A) reported in only 5 families with described cases. Recently, mutations in GATA6 have been identified in a large percentage of human cases, and a GATA4 mutant allele has been implicated in a single case. In the mouse, Gata4 and Gata6 are expressed in several endoderm-derived tissues, including the pancreas. To analyze the functions of GATA4 and/or GATA6 during mouse pancreatic development, we generated pancreas-specific deletions of Gata4 and Gata6. Surprisingly, loss of either Gata4 or Gata6 in the pancreas resulted in only mild pancreatic defects, which resolved postnatally. However, simultaneous deletion of both Gata4 and Gata6 in the pancreas caused severe pancreatic agenesis due to disruption of pancreatic progenitor cell proliferation, defects in branching morphogenesis, and a subsequent failure to induce the differentiation of progenitor cells expressing carboxypeptidase A1 (CPA1) and neurogenin 3 (NEUROG3). These studies address the conserved and nonconserved mechanisms underlying GATA4 and GATA6 function during pancreas development and provide a new mouse model to characterize the underlying developmental defects associated with pancreatic agenesis. PMID:23006325

Progressive Impairment of Lactate-based Gluconeogenesis in the Huntington's Disease Mouse Model R6/2

DEFF Research Database (Denmark)

Nielsen, Signe Marie Borch; Hasholt, Lis; Nørremølle, Anne

2015-01-01

of impairment of lactate-based hepatic gluconeogenesis in the transgenic HD mouse model R6/2 and determine that the defect manifests very early and progresses in severity with disease development, indicating a potential to explore this defect in a biomarker context. Moreover, R6/2 animals displayed lower blood...

Bioenergetic Defects and Oxidative Damage in Transgenic Mouse Models of Neurodegenerative Disorders

National Research Council Canada - National Science Library

Brown, Susan

1999-01-01

... (HE) and familial amyotrophic lateral sclerosis (FALS), using transgenic mouse models. Studies in this first year employed C-14-2-deoxyglucose in vivo autoradiography and spectrophotometric metabolic enzyme assays...

Food withdrawal lowers energy expenditure and induces inactivity in long-chain fatty acid oxidation-deficient mouse models.

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Diekman, Eugene F; van Weeghel, Michel; Wanders, Ronald J A; Visser, Gepke; Houten, Sander M

2014-07-01

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an inherited disorder of mitochondrial long-chain fatty acid β-oxidation (FAO). Patients with VLCAD deficiency may present with hypoglycemia, hepatomegaly, cardiomyopathy, and myopathy. Although several mouse models have been developed to aid in the study of the pathogenesis of long-chain FAO defects, the muscular phenotype is underexposed. To address the muscular phenotype, we used a newly developed mouse model on a mixed genetic background with a more severe defect in FAO (LCAD(-/-); VLCAD(+/-)) in addition to a validated mouse model (LCAD(-/-); VLCAD(+/+)) and compared them with wild-type (WT) mice. We found that both mouse models show a 20% reduction in energy expenditure (EE) and a 3-fold decrease in locomotor activity in the unfed state. In addition, we found a 1.7°C drop in body temperature in unfed LCAD(-/-); VLCAD(+/+) mice compared with WT body temperature. We conclude that food withdrawal-induced inactivity, hypothermia, and reduction in EE are novel phenotypes associated with FAO deficiency in mice. Unexpectedly, inactivity was not explained by rhabdomyolysis, but rather reflected the overall reduced capacity of these mice to generate heat. We suggest that mice are partly protected against the negative consequence of an FAO defect.-Diekman, E. F., van Weeghel, M., Wanders, R. J. A., Visser, G., Houten, S. M. Food withdrawal lowers energy expenditure and induces inactivity in long-chain fatty acid oxidation-deficient mouse models. © FASEB.

Ectopic expression of Ptf1a induces spinal defects, urogenital defects, and anorectal malformations in Danforth's short tail mice.

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Kei Semba

Full Text Available Danforth's short tail (Sd is a semidominant mutation on mouse chromosome 2, characterized by spinal defects, urogenital defects, and anorectal malformations. However, the gene responsible for the Sd phenotype was unknown. In this study, we identified the molecular basis of the Sd mutation. By positional cloning, we identified the insertion of an early transposon in the Sd candidate locus approximately 12-kb upstream of Ptf1a. We found that insertion of the transposon caused overexpression of three neighboring genes, Gm13344, Gm13336, and Ptf1a, in Sd mutant embryos and that the Sd phenotype was not caused by disruption of an as-yet-unknown gene in the candidate locus. Using multiple knockout and knock-in mouse models, we demonstrated that misexpression of Ptf1a, but not of Gm13344 or Gm13336, in the notochord, hindgut, cloaca, and mesonephros was sufficient to replicate the Sd phenotype. The ectopic expression of Ptf1a in the caudal embryo resulted in attenuated expression of Cdx2 and its downstream target genes T, Wnt3a, and Cyp26a1; we conclude that this is the molecular basis of the Sd phenotype. Analysis of Sd mutant mice will provide insight into the development of the spinal column, anus, and kidney.

Thymidine Kinase 2 Deficiency-Induced mtDNA Depletion in Mouse Liver Leads to Defect beta-Oxidation

OpenAIRE

Zhou, Xiaoshan; Kannisto, Kristina; Curbo, Sophie; von Dobeln, Ulrika; Hultenby, Kjell; Isetun, Sindra; Gåfvels, Mats; Karlsson, Anna

2013-01-01

Thymidine kinase 2 (TK2) deficiency in humans causes mitochondrial DNA (mtDNA) depletion syndrome. To study the molecular mechanisms underlying the disease and search for treatment options, we previously generated and described a TK2 deficient mouse strain (TK2(-/-)) that progressively loses its mtDNA. The TK2(-/-) mouse model displays symptoms similar to humans harboring TK2 deficient infantile fatal encephalomyopathy. Here, we have studied the TK2(-/-) mouse model to clarify the pathologica...

Mitotic defects lead to pervasive aneuploidy and accompany loss of RB1 activity in mouse LmnaDhe dermal fibroblasts.

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C Herbert Pratt

2011-03-01

Full Text Available Lamin A (LMNA is a component of the nuclear lamina and is mutated in several human diseases, including Emery-Dreifuss muscular dystrophy (EDMD; OMIM ID# 181350 and the premature aging syndrome Hutchinson-Gilford progeria syndrome (HGPS; OMIM ID# 176670. Cells from progeria patients exhibit cell cycle defects in both interphase and mitosis. Mouse models with loss of LMNA function have reduced Retinoblastoma protein (RB1 activity, leading to aberrant cell cycle control in interphase, but how mitosis is affected by LMNA is not well understood.We examined the cell cycle and structural phenotypes of cells from mice with the Lmna allele, Disheveled hair and ears (Lmna(Dhe. We found that dermal fibroblasts from heterozygous Lmna(Dhe (Lmna(Dhe/+ mice exhibit many phenotypes of human laminopathy cells. These include severe perturbations to the nuclear shape and lamina, increased DNA damage, and slow growth rates due to mitotic delay. Interestingly, Lmna(Dhe/+ fibroblasts also had reduced levels of hypophosphorylated RB1 and the non-SMC condensin II-subunit D3 (NCAP-D3, a mitosis specific centromere condensin subunit that depends on RB1 activity. Mitotic check point control by mitotic arrest deficient-like 1 (MAD2L1 also was perturbed in Lmna(Dhe/+ cells. Lmna(Dhe/+ fibroblasts were consistently aneuploid and had higher levels of micronuclei and anaphase bridges than normal fibroblasts, consistent with chromosome segregation defects.These data indicate that RB1 may be a key regulator of cellular phenotype in laminopathy-related cells, and suggest that the effects of LMNA on RB1 include both interphase and mitotic cell cycle control.

Mitotic Defects Lead to Pervasive Aneuploidy and Accompany Loss of RB1 Activity in Mouse LmnaDhe Dermal Fibroblasts

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Pratt, C. Herbert; Curtain, Michelle; Donahue, Leah Rae; Shopland, Lindsay S.

2011-01-01

Background Lamin A (LMNA) is a component of the nuclear lamina and is mutated in several human diseases, including Emery-Dreifuss muscular dystrophy (EDMD; OMIM ID# 181350) and the premature aging syndrome Hutchinson-Gilford progeria syndrome (HGPS; OMIM ID# 176670). Cells from progeria patients exhibit cell cycle defects in both interphase and mitosis. Mouse models with loss of LMNA function have reduced Retinoblastoma protein (RB1) activity, leading to aberrant cell cycle control in interphase, but how mitosis is affected by LMNA is not well understood. Results We examined the cell cycle and structural phenotypes of cells from mice with the Lmna allele, Disheveled hair and ears (LmnaDhe). We found that dermal fibroblasts from heterozygous LmnaDhe (LmnaDhe/+) mice exhibit many phenotypes of human laminopathy cells. These include severe perturbations to the nuclear shape and lamina, increased DNA damage, and slow growth rates due to mitotic delay. Interestingly, LmnaDhe/+ fibroblasts also had reduced levels of hypophosphorylated RB1 and the non-SMC condensin II-subunit D3 (NCAP-D3), a mitosis specific centromere condensin subunit that depends on RB1 activity. Mitotic check point control by mitotic arrest deficient-like 1 (MAD2L1) also was perturbed in LmnaDhe /+ cells. LmnaDhe /+ fibroblasts were consistently aneuploid and had higher levels of micronuclei and anaphase bridges than normal fibroblasts, consistent with chromosome segregation defects. Conclusions These data indicate that RB1 may be a key regulator of cellular phenotype in laminopathy-related cells, and suggest that the effects of LMNA on RB1 include both interphase and mitotic cell cycle control. PMID:21464947

Lack of metformin effect on mouse embryo AMPK activity: implications for metformin treatment during pregnancy.

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Lee, Hyung-Yul; Wei, Dan; Loeken, Mary R

2014-01-01

Adenosine monophosphate-activated protein kinase (AMPK) is stimulated in embryos during diabetic pregnancy by maternal hyperglycaemia-induced embryo oxidative stress. Stimulation of AMPK disrupts embryo gene expression and causes neural tube defects. Metformin, which may be taken during early pregnancy, has been reported to stimulate AMPK activity. Thus, the benefits of improved glycaemic control could be offset by stimulated embryo AMPK activity. Here, we investigated whether metformin can stimulate AMPK activity in mouse embryos and can adversely affect embryo gene expression and neural tube defects. Pregnant nondiabetic mice were administered metformin beginning on the first day of pregnancy. Activation of maternal and embryo AMPK [phospho-AMPK α (Thr172) relative to total AMPK], expression of Pax3, a gene required for neural tube closure, and neural tube defects were studied. Mouse embryonic stem cells were used as a cell culture model of embryonic neuroepithelium to study metformin effects on AMPK and Pax3 expression. Metformin had no effect on AMPK in embryos or maternal skeletal muscle but increased activated AMPK in maternal liver. Metformin did not inhibit Pax3 expression or increase neural tube defects. However, metformin increased activated AMPK and inhibited Pax3 expression by mouse embryonic stem cells. Mate1/Slc47a1 and Oct3/Slc22a, which encode metformin transporters, were expressed at barely detectable levels by embryos. Although metformin can have effects associated with diabetic embryopathy in vitro, the lack of effects on mouse embryos in vivo may be due to lack of metformin transporters and indicates that the benefits of metformin on glycaemic control are not counteracted by stimulation of embryo AMPK activity and consequent embryopathy. Copyright © 2013 John Wiley & Sons, Ltd.

Hair Follicle Morphogenesis in the Treatment of Mouse Full-Thickness Skin Defects Using Composite Human Acellular Amniotic Membrane and Adipose Derived Mesenchymal Stem Cells

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Wu Minjuan

2016-01-01

Full Text Available Early repair of skin injury and maximal restoration of the function and appearance have become important targets of clinical treatment. In the present study, we observed the healing process of skin defects in nude mice and structural characteristics of the new skin after transplantation of isolated and cultured adipose derived mesenchymal stem cells (ADMSCs onto the human acellular amniotic membrane (AAM. The result showed that ADMSCs were closely attached to the surface of AAM and grew well 24 h after seeding. Comparison of the wound healing rate at days 7, 14, and 28 after transplantation showed that ADMSCs seeded on AAM facilitated the healing of full-thickness skin wounds more effectively as compared with either hAM or AAM alone, indicating that ADMSCs participated in skin regeneration. More importantly, we noticed a phenomenon of hair follicle development during the process of skin repair. Composite ADMSCs and AAM not only promoted the healing of the mouse full-thickness defects but also facilitated generation of the appendages of the affected skin, thus promoting restoration of the skin function. Our results provide a new possible therapy idea for the treatment of skin wounds with respect to both anatomical regeneration and functional restoration.

PTPBR7 binding proteins in myelinating neurons of the mouse brain

NARCIS (Netherlands)

Chesini, I.M.; Debyser, G.; Croes, H.J.E.; Dam, G.B. ten; Devreese, B.; Stoker, A.W.; Hendriks, W.J.A.J.

2011-01-01

Mouse protein tyrosine phosphatase PTPBR7 is a receptor-like, transmembrane protein that is localized on the surface of neuronal cells. Its protein phosphatase activity is reduced upon multimerization, and PTPBR7-deficient mice display motor coordination defects. Extracellular molecules that may

Electroretinographic genotype-phenotype correlations for mouse and man at the dmd/DMD locus

Energy Technology Data Exchange (ETDEWEB)

Millers, D.M.; Weleber, R.G.; Woodward, W.R. [Oregon Health Sciences Univ., Portland, OR (United States)] [and others

1994-09-01

Reduced or absent b-waves in the dark-adapted electroretinogram (ERG) of Duchenne and Becker muscular dystrophy (DMD/BMD) patients led to the identification of dystrophin in human retina and the proposal that it plays a role in retinal electrophysiology. Study of a large group of Duchenne and Becker muscular dystrophy males to determine their ocular characteristics indicated that there were position-specific effects of deletions, with 3{prime} defects associated with severe electroretinographic changes, whereas some 5{prime} patients demonstrated less severe, or even normal, ERGs. We studied the mdx mouse, a model with X-linked muscular dystrophy and defective full-length dystrophin, which failed to show any ERG abnormalities. Given the presence of alternate isoforms of dystrophin in retina, and the 5{prime} deletion DMD/BMD patients with normal ERGs, we studied mouse models with differing dystrophin mutations (mdx{sup Cv3}, mdx{sup Cv5}) to determine the usefulness of alternate strains as models for the visual effects of dystropin. Abnormal ERGs similar to those seen in DMD/BMS patients exist in the mdx{sup Cv3} strain of muscular dystrophy mice. Normal ERGs were found the mdx{sup Cv5} strain. The mutations in the mdx and mdx{sup Cv5} mice have been mapped to the 5{prime} end of the dmd gene, while the mutation in the mdx{sup Cv3} mouse is in the 3{prime} end. Thus, there are position effects of the gene defect on the ERG phenotype that are conserved in the mouse. Such genotype-phenotype correlations may reflect differential expression of shorter isoforms of dystrophin.

Behavioral Abnormalities and Circuit Defects in the Basal Ganglia of a Mouse Model of 16p11.2 Deletion Syndrome

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Thomas Portmann

2014-05-01

Full Text Available A deletion on human chromosome 16p11.2 is associated with autism spectrum disorders. We deleted the syntenic region on mouse chromosome 7F3. MRI and high-throughput single-cell transcriptomics revealed anatomical and cellular abnormalities, particularly in cortex and striatum of juvenile mutant mice (16p11+/−. We found elevated numbers of striatal medium spiny neurons (MSNs expressing the dopamine D2 receptor (Drd2+ and fewer dopamine-sensitive (Drd1+ neurons in deep layers of cortex. Electrophysiological recordings of Drd2+ MSN revealed synaptic defects, suggesting abnormal basal ganglia circuitry function in 16p11+/− mice. This is further supported by behavioral experiments showing hyperactivity, circling, and deficits in movement control. Strikingly, 16p11+/− mice showed a complete lack of habituation reminiscent of what is observed in some autistic individuals. Our findings unveil a fundamental role of genes affected by the 16p11.2 deletion in establishing the basal ganglia circuitry and provide insights in the pathophysiology of autism.

Ceramic-polylactide composite material used in a model of healing of osseous defects in rabbits.

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Myciński, Paweł; Zarzecka, Joanna; Skórska-Stania, Agnieszka; Jelonek, Agnieszka; Okoń, Krzysztof; Wróbel, Maria

The growing demand for various kinds of bone regeneration material has in turn increased the desire to find materials with optimal physical, chemical, and biological properties. The objective of the present study was to identify the proportions of ceramic and polylactide components in a bone substitute material prepared in collaboration with the Crystal Chemistry of Drugs Team of the Faculty of Chemistry at the Jagiellonian University, which would be optimal for bone regeneration processes. Another goal was to provide a histological analysis of the influence of a ceramic-polylactide composite on the healing of osseous defects in rabbits. The study was performed on laboratory animals (18 New Zealand White rabbits). The following study groups were formed: - group A (study group, 9 animals) - in this group we performed a histological analysis of healing with a ceramic-polylactide composite based on an 80/20 mix of hydroxyapatite and polylactide; - group B (study group, 9 animals) - in this group we performed a histological analysis of healing with a ceramic-polylactide composite with a reduced amount of hydroxyapatite compared to the previous group, i.e. in a ratio of 61/39; - group K (control, 18 animals) - the control group comprised self-healing, standardised osseous defects prepared in the calvarial bone of the rabbits on the contralateral side. In the assessment of histological samples, we were also able to eliminate individual influences that might have led to differentiation in wound healing. The material used in the histological analysis took the form of rabbit bone tissue samples, containing both defects, with margins of around 0.5 cm, taken 1, 3, and 6 months after the experiment. The osseous defects from groups A and B filled with ceramic-polylactide material healed with less inflammatory infiltration than was the case with control group K. They were also characterised by faster regression, and no resorption or osteonecrosis, which allowed for better

Preclinical study of mouse pluripotent parthenogenetic embryonic stem cell derivatives for the construction of tissue-engineered skin equivalent.

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Rao, Yang; Cui, Jihong; Yin, Lu; Liu, Wei; Liu, Wenguang; Sun, Mei; Yan, Xingrong; Wang, Ling; Chen, Fulin

2016-10-22

Embryonic stem cell (ESC) derivatives hold great promise for the construction of tissue-engineered skin equivalents (TESE). However, harvesting of ESCs destroys viable embryos and may lead to political and ethical concerns over their application. In the current study, we directed mouse parthenogenetic embryonic stem cells (pESCs) to differentiate into fibroblasts, constructed TESE, and evaluated its function in vivo. The stemness marker expression and the pluripotent differentiation ability of pESCs were tested. After embryoid body (EB) formation and adherence culture, mesenchymal stem cells (MSCs) were enriched and directed to differentiate into fibroblastic lineage. Characteristics of derived fibroblasts were assessed by quantitative real-time PCR and ELISA. Functional ability of the constructed TESE was tested by a mouse skin defects repair model. Mouse pESCs expressed stemness marker and could form teratoma containing three germ layers. MSCs could be enriched from outgrowths of EBs and directed to differentiate into fibroblastic lineage. These cells express a high level of growth factors including FGF, EGF, VEGF, TGF, PDGF, and IGF1, similar to those of ESC-derived fibroblasts and mouse fibroblasts. Seeded into collagen gels, the fibroblasts derived from pESCs could form TESE. Mouse skin defects could be successfully repaired 15 days after transplantation of TESE constructed by fibroblasts derived from pESCs. pESCs could be induced to differentiate into fibroblastic lineage, which could be applied to the construction of TESE and skin defect repair. Particularly, pESC derivatives avoid the limitations of political and ethical concerns, and provide a promising source for regenerative medicine.

Histomorphometric evaluation of bone regeneration using autogenous bone and beta-tricalcium phosphate in diabetic rabbits

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Živadinović Milka

2016-01-01

Full Text Available Background/Aim. The mechanism of impaired bone healing in diabetes mellitus includes different tissue and cellular level activities due to micro- and macrovascular changes. As a chronic metabolic disease with vascular complications, diabetes affects a process of bone regeneration as well. The therapeutic approach in bone regeneration is based on the use of osteoinductive autogenous grafts as well as osteoconductive synthetic material, like a β-tricalcium phosphate. The aim of the study was to determine the quality and quantity of new bone formation after the use of autogenous bone and β-tricalcium phosphate in the model of calvarial critical-sized defect in rabbits with induced diabetes mellitus type I. Methods. The study included eight 4-month-old Chincilla rabbits with alloxan-induced diabetes mellitus type I. In all animals, there were surgically created two calvarial bilateral defects (diameter 12 mm, which were grafted with autogenous bone and β-tricalcium phosphate (n = 4 or served as unfilled controls (n = 4. After 4 weeks of healing, animals were sacrificed and calvarial bone blocks were taken for histologic and histomorphometric analysis. Beside descriptive histologic evaluation, the percentage of new bone formation, connective tissue and residual graft were calculated. All parameters were statistically evaluated by Friedman Test and post hock Wilcoxon Singed Ranks Test with a significance of p < 0.05. Results. Histology revealed active new bone formation peripherally with centrally located connective tissue, newly formed woven bone and well incorporated residual grafts in all treated defects. Control samples showed no bone bridging of defects. There was a significantly more new bone in autogeonous graft (53% compared with β-tricalcium phosphate (30%, (p < 0.030 and control (7%, (p < 0.000 groups. A significant difference was also recorded between β-tricalcium phosphate and control groups (p < 0.008. Conclusion. In the present

Chorioallantoic placenta defects in cloned mice

International Nuclear Information System (INIS)

Wakisaka-Saito, Noriko; Kohda, Takashi; Inoue, Kimiko; Ogonuki, Narumi; Miki, Hiromi; Hikichi, Takafusa; Mizutani, Eiji; Wakayama, Teruhiko; Kaneko-Ishino, Tomoko; Ogura, Atsuo; Ishino, Fumitoshi

2006-01-01

Somatic cell nuclear transfer technology has been applied to produce live clones successfully in several mammalian species, but the success rates are very low. In mice, about half of the nuclear transfer embryos undergo implantation, but very few survive to term. We undertook detailed histological analyses of placentas from cloned mouse embryos generated from cumulus cells at 10.5 dpc of pregnancy, by which stage most clones have terminated their development. At 10.5 dpc, the extraembryonic tissues displayed several defined histological patterns, each reflecting their stage of developmental arrest. The most notable abnormality was the poor development of the spongiotrophoblast layer of diploid cells. This is in contrast to the placental hyperplasia frequently observed in somatic clones at 12.5 dpc or later stages. A variety of structural abnormalities were also observed in the embryos. Both placental and embryonic defects likely contribute to the low success rate of the mouse clones

Genotypic and phenotypic characterization of the Sdccag8Tn(sb-Tyr2161B.CA1C2Ove mouse model.

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Katie Weihbrecht

Full Text Available Nephronophthisis-related ciliopathies (NPHP-RC are a group of disorders that present with end-stage renal failure in childhood/adolescence, kidney cysts, retinal degeneration, and cerebellar hypoplasia. One disorder that shares clinical features with NPHP-RC is Bardet-Biedl Syndrome (BBS. Serologically defined colon cancer antigen 8 (SDCCAG8; also known as NPHP10 and BBS16 is an NPHP gene that is also associated with BBS. To better understand the patho-mechanisms of NPHP and BBS caused by loss of SDCCAG8 function, we characterized an SDCCAG8 mouse model (Sdccag8Tn(sb-Tyr2161B.CA1C2Ove generated by Sleeping Beauty Transposon (SBT-mediated insertion mutagenesis. Consistent with the previously reported, independent SDCCAG8 mouse models, our mutant mice display pre-axial polydactyly in their hind limbs. In addition, we report patterning defects in the secondary palate, brain abnormalities, as well as neonatal lethality associated with developmental defects in the lung in our mouse model. The neonatal lethality phenotype is genetic background dependent and rescued by introducing 129S6/SvEvTac background. Genetic modifier(s responsible for this effect were mapped to a region between SNPs rs3714172 and rs3141832 on chromosome 11. While determining the precise genetic lesion in our mouse model, we found that SBT insertion resulted in a deletion of multiple exons from both Sdccag8 and its neighboring gene Akt3. We ascribe the patterning defects in the limb and the secondary palate as well as lung abnormalities to loss of SDCCAG8, while the developmental defects in the brain are likely due to the loss of AKT3. This mouse model may be useful to study features not observed in other SDCCAG8 models but cautions are needed in interpreting data.

A Comprehensive Atlas of the Adult Mouse Penis

Science.gov (United States)

Phillips, Tiffany R.; Wright, David K.; Gradie, Paul E.; Johnston, Leigh A.; Pask, Andrew J.

2016-01-01

Mice are routinely used to study the development of the external genitalia and, in particular, the process of male urethral closure. This is because misplacement of the male penile urethra, or hypospadias, is amongst the most common birth defects reported in humans. While mice present a tractable model to study penile development, several structures differ between mice and humans, and there is a lack of consensus in the literature on their annotation and developmental origins. Defining the ontology of the mouse prepuce is especially important for the relevance and interpretation of mouse models of hypospadias to human conditions. We have developed a detailed annotation of the adult mouse penis that addresses these differences and enables an accurate comparison of murine and human hypospadias phenotypes. Through MRI data, gross morphology and section histology, we define the origin of the mouse external and internal prepuces, their relationship to the single human foreskin as well as provide a comprehensive view of the various structures of the mouse penis and their associated muscle attachments within the body. These data are combined to annotate structures in a novel 3D adult penis atlas that can be downloaded, viewed at any angle, and manipulated to examine the relationship of various structures. PMID:26112156

Rudhira/BCAS3 is essential for mouse development and cardiovascular patterning.

Science.gov (United States)

Shetty, Ronak; Joshi, Divyesh; Jain, Mamta; Vasudevan, Madavan; Paul, Jasper Chrysolite; Bhat, Ganesh; Banerjee, Poulomi; Abe, Takaya; Kiyonari, Hiroshi; VijayRaghavan, K; Inamdar, Maneesha S

2018-04-04

Rudhira/Breast Carcinoma Amplified Sequence 3 (BCAS3) is a cytoskeletal protein that promotes directional cell migration and angiogenesis in vitro and is implicated in human carcinomas and coronary artery disease. To study the role of Rudhira during development in vivo, we generated the first knockout mouse for rudhira and show that Rudhira is essential for mouse development. Rudhira null embryos die at embryonic day (E) 9.5 accompanied by severe vascular patterning defects in embryonic and extra-embryonic tissues. To identify the molecular processes downstream of rudhira, we analyzed the transcriptome of intact knockout yolk sacs. Genome-wide transcriptome analysis showed that Rudhira functions in angiogenesis and its related processes such as cell adhesion, extracellular matrix organization, peptidase activity and TGFβ signaling. Since Rudhira is also expressed in endothelial cells (ECs), we further generated Tie2Cre-mediated endothelial knockout (CKO) of rudhira. CKO embryos survive to E11.5 and similar to the global knockout, display gross vascular patterning defects, showing that endothelial Rudhira is vital for development. Further, Rudhira knockdown ECs in culture fail to sprout in a spheroid-sprouting assay, strongly supporting its role in vascular patterning. Our study identifies an essential role for Rudhira in blood vessel remodeling and provides a mouse model for cardiovascular development.

Inositol- and folate-resistant neural tube defects in mice lacking the epithelial-specific factor Grhl-3.

Science.gov (United States)

Ting, Stephen B; Wilanowski, Tomasz; Auden, Alana; Hall, Mark; Voss, Anne K; Thomas, Tim; Parekh, Vishwas; Cunningham, John M; Jane, Stephen M

2003-12-01

The neural tube defects (NTDs) spina bifida and anencephaly are widely prevalent severe birth defects. The mouse mutant curly tail (ct/ct) has served as a model of NTDs for 50 years, even though the responsible genetic defect remained unrecognized. Here we show by gene targeting, mapping and genetic complementation studies that a mouse homolog of the Drosophila grainyhead (grh) gene, grainyhead-like-3 (Grhl3), is a compelling candidate for the gene underlying the curly tail phenotype. The NTDs in Grhl3-null mice are more severe than those in the curly tail strain, as the Grhl3 alleles in ct/ct mice are hypomorphic. Spina bifida in ct/ct mice is folate resistant, but its incidence can be markedly reduced by maternal inositol supplementation periconceptually. The NTDs in Grhl3-/- embryos are also folate resistant, but unlike those in ct/ct mice, they are resistant to inositol. These findings suggest that residual Grhl3 expression in ct/ct mice may be required for inositol rescue of folate-resistant NTDs.

A mammalian model for Laron syndrome produced by targeted disruption of the mouse growth hormone receptor/binding protein gene (the Laron mouse)

Science.gov (United States)

Zhou, Yihua; Xu, Bixiong C.; Maheshwari, Hiralal G.; He, Li; Reed, Michael; Lozykowski, Maria; Okada, Shigeru; Cataldo, Lori; Coschigamo, Karen; Wagner, Thomas E.; Baumann, Gerhard; Kopchick, John J.

1997-01-01

Laron syndrome [growth hormone (GH) insensitivity syndrome] is a hereditary dwarfism resulting from defects in the GH receptor (GHR) gene. GHR deficiency has not been reported in mammals other than humans. Many aspects of GHR dysfunction remain unknown because of ethical and practical limitations in studying humans. To create a mammalian model for this disease, we generated mice bearing a disrupted GHR/binding protein (GHR/BP) gene through a homologous gene targeting approach. Homozygous GHR/BP knockout mice showed severe postnatal growth retardation, proportionate dwarfism, absence of the GHR and GH binding protein, greatly decreased serum insulin-like growth factor I and elevated serum GH concentrations. These characteristics represent the phenotype typical of individuals with Laron syndrome. Animals heterozygous for the GHR/BP defect show only minimal growth impairment but have an intermediate biochemical phenotype, with decreased GHR and GH binding protein expression and slightly diminished insulin-like growth factor I levels. These findings indicate that the GHR/BP-deficient mouse (Laron mouse) is a suitable model for human Laron syndrome that will prove useful for the elucidation of many aspects of GHR/BP function that cannot be obtained in humans. PMID:9371826

A mammalian model for Laron syndrome produced by targeted disruption of the mouse growth hormone receptor/binding protein gene (the Laron mouse).

Science.gov (United States)

Zhou, Y; Xu, B C; Maheshwari, H G; He, L; Reed, M; Lozykowski, M; Okada, S; Cataldo, L; Coschigamo, K; Wagner, T E; Baumann, G; Kopchick, J J

1997-11-25

Laron syndrome [growth hormone (GH) insensitivity syndrome] is a hereditary dwarfism resulting from defects in the GH receptor (GHR) gene. GHR deficiency has not been reported in mammals other than humans. Many aspects of GHR dysfunction remain unknown because of ethical and practical limitations in studying humans. To create a mammalian model for this disease, we generated mice bearing a disrupted GHR/binding protein (GHR/BP) gene through a homologous gene targeting approach. Homozygous GHR/BP knockout mice showed severe postnatal growth retardation, proportionate dwarfism, absence of the GHR and GH binding protein, greatly decreased serum insulin-like growth factor I and elevated serum GH concentrations. These characteristics represent the phenotype typical of individuals with Laron syndrome. Animals heterozygous for the GHR/BP defect show only minimal growth impairment but have an intermediate biochemical phenotype, with decreased GHR and GH binding protein expression and slightly diminished insulin-like growth factor I levels. These findings indicate that the GHR/BP-deficient mouse (Laron mouse) is a suitable model for human Laron syndrome that will prove useful for the elucidation of many aspects of GHR/BP function that cannot be obtained in humans.

Periodontal Defects in the A116T Knock-in Murine Model of Odontohypophosphatasia.

Science.gov (United States)

Foster, B L; Sheen, C R; Hatch, N E; Liu, J; Cory, E; Narisawa, S; Kiffer-Moreira, T; Sah, R L; Whyte, M P; Somerman, M J; Millán, J L

2015-05-01

Mutations in ALPL result in hypophosphatasia (HPP), a disease causing defective skeletal mineralization. ALPL encodes tissue nonspecific alkaline phosphatase (ALP), an enzyme that promotes mineralization by reducing inorganic pyrophosphate, a mineralization inhibitor. In addition to skeletal defects, HPP causes dental defects, and a mild clinical form of HPP, odontohypophosphatasia, features only a dental phenotype. The Alpl knockout (Alpl (-/-)) mouse phenocopies severe infantile HPP, including profound skeletal and dental defects. However, the severity of disease in Alpl (-/-) mice prevents analysis at advanced ages, including studies to target rescue of dental tissues. We aimed to generate a knock-in mouse model of odontohypophosphatasia with a primarily dental phenotype, based on a mutation (c.346G>A) identified in a human kindred with autosomal dominant odontohypophosphatasia. Biochemical, skeletal, and dental analyses were performed on the resulting Alpl(+/A116T) mice to validate this model. Alpl(+/A116T) mice featured 50% reduction in plasma ALP activity compared with wild-type controls. No differences in litter size, survival, or body weight were observed in Alpl(+/A116T) versus wild-type mice. The postcranial skeleton of Alpl(+/A116T) mice was normal by radiography, with no differences in femur length, cortical/trabecular structure or mineral density, or mechanical properties. Parietal bone trabecular compartment was mildly altered. Alpl(+/A116T) mice featured alterations in the alveolar bone, including radiolucencies and resorptive lesions, osteoid accumulation on the alveolar bone crest, and significant differences in several bone properties measured by micro-computed tomography. Nonsignificant changes in acellular cementum did not appear to affect periodontal attachment or function, although circulating ALP activity was correlated significantly with incisor cementum thickness. The Alpl(+/A116T) mouse is the first model of odontohypophosphatasia

Eye abnormalities in the mouse fetus and postnatal mice caused by x-radiation of 150 R on the 7th day of gestation

International Nuclear Information System (INIS)

Hashimoto, Masaru

1976-01-01

X-ray of 150 R was irradiated once to the whole body of ddN mouse on the 7th day of gestation, and eye abnormalities in the mouse embryos of 18 days and in mouse youngs of 4 weeks after birth were observed externally and histologically. In the observation of the mouse embryos of 18 days, microphthalmus, anophthalmia, retinal reversion and distorsion due to eyecup insufficiency, and cornea abnormalities were recognized, and these eye abnormalities were also recognized in the mouse youngs of 4 weeks. Histological findings of congenital corneal opacity and accretion of the cornea and the crystalline lens in the mouse youngs and the mouse embryos of 18 days were the same kinds, and a common feature was the defect of the corneal parenchyma. These were caused by disorder of segregation from ectoblast of epidermis cuticle of crystalline lens. Histological findings equal to that of hereditary defect of the uvea were recognized after birth, and histological findings which seemed to be changes during the embryonal period were obtained. This was thought to be caused by eyecup insufficiency. Histological findings as same as those of clinical ''Retinal Dysplasia'' were obtained in mice after birth, and embryos with retinal distorsion, strong primary residue of the vitreous body, and defect of the choriod, which seemed to be changes of retinal dysplasia during the embryonal period, were recognized. This was thought to be caused by eyecup insufficiency. Anophthalmia was observed in the embryos and the youngs, there were some traces of eye tissues, and all cases were secondary anophthalmus. Aphacia which was found in the embryos was not recognized in any case of the young after birth. (tsunoda, M.)

Mechanism of testosterone deficiency in the transgenic sickle cell mouse.

Directory of Open Access Journals (Sweden)

Biljana Musicki

Full Text Available Testosterone deficiency is associated with sickle cell disease (SCD, but its underlying mechanism is not known. We investigated the possible occurrence and mechanism of testosterone deficiency in a mouse model of human SCD. Transgenic sickle male mice (Sickle exhibited decreased serum and intratesticular testosterone and increased luteinizing hormone (LH levels compared with wild type (WT mice, indicating primary hypogonadism in Sickle mice. LH-, dbcAMP-, and pregnenolone- (but not 22-hydroxycholesterol- stimulated testosterone production by Leydig cells isolated from the Sickle mouse testis was decreased compared to that of WT mice, implying defective Leydig cell steroidogenesis. There also was reduced protein expression of steroidogenic acute regulatory protein (STAR, but not cholesterol side-chain cleavage enzyme (P450scc, in the Sickle mouse testis. These data suggest that the capacity of P450scc to support testosterone production may be limited by the supply of cholesterol to the mitochondria in Sickle mice. The sickle mouse testis exhibited upregulated NADPH oxidase subunit gp91phox and increased oxidative stress, measured as 4-hydroxy-2-nonenal, and unchanged protein expression of an antioxidant glutathione peroxidase-1. Mice heterozygous for the human sickle globin (Hemi exhibited intermediate hypogonadal changes between those of WT and Sickle mice. These results demonstrate that testosterone deficiency occurs in Sickle mice, mimicking the human condition. The defects in the Leydig cell steroidogenic pathway in Sickle mice, mainly due to reduced availability of cholesterol for testosterone production, may be related to NADPH oxidase-derived oxidative stress. Our findings suggest that targeting testicular oxidative stress or steroidogenesis mechanisms in SCD offers a potential treatment for improving phenotypic changes associated with testosterone deficiency in this disease.

Cytoskeletal defects in Bmpr2-associated pulmonary arterial hypertension.

Science.gov (United States)

Johnson, Jennifer A; Hemnes, Anna R; Perrien, Daniel S; Schuster, Manfred; Robinson, Linda J; Gladson, Santhi; Loibner, Hans; Bai, Susan; Blackwell, Tom R; Tada, Yuji; Harral, Julie W; Talati, Megha; Lane, Kirk B; Fagan, Karen A; West, James

2012-03-01

The heritable form of pulmonary arterial hypertension (PAH) is typically caused by a mutation in bone morphogenic protein receptor type 2 (BMPR2), and mice expressing Bmpr2 mutations develop PAH with features similar to human disease. BMPR2 is known to interact with the cytoskeleton, and human array studies in PAH patients confirm alterations in cytoskeletal pathways. The goal of this study was to evaluate cytoskeletal defects in BMPR2-associated PAH. Expression arrays on our Bmpr2 mutant mouse lungs revealed cytoskeletal defects as a prominent molecular consequence of universal expression of a Bmpr2 mutation (Rosa26-Bmpr2(R899X)). Pulmonary microvascular endothelial cells cultured from these mice have histological and functional cytoskeletal defects. Stable transfection of different BMPR2 mutations into pulmonary microvascular endothelial cells revealed that cytoskeletal defects are common to multiple BMPR2 mutations and are associated with activation of the Rho GTPase, Rac1. Rac1 defects are corrected in cell culture and in vivo through administration of exogenous recombinant human angiotensin-converting enzyme 2 (rhACE2). rhACE2 reverses 77% of gene expression changes in Rosa26-Bmpr2(R899X) transgenic mice, in particular, correcting defects in cytoskeletal function. Administration of rhACE2 to Rosa26-Bmpr2(R899X) mice with established PAH normalizes pulmonary pressures. Together, these findings suggest that cytoskeletal function is central to the development of BMPR2-associated PAH and that intervention against cytoskeletal defects may reverse established disease.

The Oak Ridge Polycystic Kidney mouse: modeling ciliopathies of mice and men.

Energy Technology Data Exchange (ETDEWEB)

Lehman, J M [University of Alabama, Birmingham; Michaud III, Edward J [ORNL; Schoeb, T [University of Alabama, Birmingham; Aydin Son, Yesim [University of Tennessee, Knoxville (UTK); Miller, M [University of Alabama, Birmingham; Yoder, Bradley [University of Alabama, Birmingham

2008-08-01

The Oak Ridge Polycystic Kidney (ORPK) mouse was described nearly 14 years ago as a model for human recessive polycystic kidney disease. The ORPK mouse arose through integration of a transgene into an intron of the Ift88 gene resulting in a hypomorphic allele (Ift88Tg737Rpw). The Ift88Tg737Rpw mutation impairs intraflagellar transport (IFT), a process required for assembly of motile and immotile cilia. Historically, the primary immotile cilium was thought to have minimal importance for human health; however, a rapidly expanding number of human disorders have now been attributed to ciliary defects. Importantly, many of these phenotypes are present and can be analyzed using the ORPK mouse. In this review, we highlight the research conducted using the OPRK mouse and the phenotypes shared with human cilia disorders. Furthermore, we describe an additional follicular dysplasia phenotype in the ORPK mouse, which alongside the ectodermal dysplasias seen in human Ellis-van Creveld and Sensenbrenner's syndromes, suggests an unappreciated role for primary cilia in the skin and hair follicle.

Embryonic Lethality of Mitochondrial Pyruvate Carrier 1 Deficient Mouse Can Be Rescued by a Ketogenic Diet

OpenAIRE

Vanderperre, Beno?t; Herzig, S?bastien; Krznar, Petra; H?rl, Manuel; Ammar, Zeinab; Montessuit, Sylvie; Pierredon, Sandra; Zamboni, Nicola; Martinou, Jean-Claude

2016-01-01

Mitochondrial import of pyruvate by the mitochondrial pyruvate carrier (MPC) is a central step which links cytosolic and mitochondrial intermediary metabolism. To investigate the role of the MPC in mammalian physiology and development, we generated a mouse strain with complete loss of MPC1 expression. This resulted in embryonic lethality at around E13.5. Mouse embryonic fibroblasts (MEFs) derived from mutant mice displayed defective pyruvate-driven respiration as well as perturbed metabolic p...

Disruption of PC1/3 expression in mice causes dwarfism and multiple neuroendocrine peptide processing defects

DEFF Research Database (Denmark)

Zhu, Xiaorong; Zhou, An; Dey, Arunangsu

2002-01-01

vertebrates and invertebrates. Disruption of the gene-encoding mouse PC1/3 has now been accomplished and results in a syndrome of severe postnatal growth impairment and multiple defects in processing many hormone precursors, including hypothalamic growth hormone-releasing hormone (GHRH), pituitary...

BMP9 ameliorates amyloidosis and the cholinergic defect in a mouse model of Alzheimer's disease.

Science.gov (United States)

Burke, Rebecca M; Norman, Timothy A; Haydar, Tarik F; Slack, Barbara E; Leeman, Susan E; Blusztajn, Jan Krzysztof; Mellott, Tiffany J

2013-11-26

Bone morphogenetic protein 9 (BMP9) promotes the acquisition of the cholinergic phenotype in basal forebrain cholinergic neurons (BFCN) during development and protects these neurons from cholinergic dedifferentiation following axotomy when administered in vivo. A decline in BFCN function occurs in patients with Alzheimer's disease (AD) and contributes to the AD-associated memory deficits. We infused BMP9 intracerebroventricularly for 7 d in transgenic AD model mice expressing green fluorescent protein specifically in cholinergic neurons (APP.PS1/CHGFP) and in wild-type littermate controls (WT/CHGFP). We used 5-mo-old mice, an age when the AD transgenics display early amyloid deposition and few cholinergic defects, and 10-mo-old mice, by which time these mice exhibit established disease. BMP9 infusion reduced the number of Aβ42-positive amyloid plaques in the hippocampus and cerebral cortex of 5- and 10-mo-old APP.PS1/CHGFP mice and reversed the reductions in choline acetyltransferase protein levels in the hippocampus of 10-mo-old APP.PS1/CHGFP mice. The treatment increased cholinergic fiber density in the hippocampus of both WT/CHGFP and APP.PS1/CHGFP mice at both ages. BMP9 infusion also increased hippocampal levels of neurotrophin 3, insulin-like growth factor 1, and nerve growth factor and of the nerve growth factor receptors, tyrosine kinase receptor A and p75/NGFR, irrespective of the genotype of the mice. These data show that BMP9 administration is effective in reducing the Aβ42 amyloid plaque burden, reversing cholinergic neuron abnormalities, and generating a neurotrophic milieu for BFCN in a mouse model of AD and provide evidence that the BMP9-signaling pathway may constitute a therapeutic target for AD.

Small intestinal submucosa: A potential osteoconductive and osteoinductive biomaterial for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Li, Mei [Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211 (China); Ningbo Medical Science Research Institute, Ningbo, Zhejiang 315020 (China); Zhang, Chi; Cheng, Mengjie; Gu, Qiaoqiao [Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211 (China); Zhao, Jiyuan, E-mail: zhaojiyuan@nbu.edu.cn [Zhejiang Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, Zhejiang 315211 (China)

2017-06-01

SIS is an acellular, naturally occurring collagenous extracellular matrix (ECM) material with various bioactive factors, which broadly applied in tissue engineering in clinic. Several studies have applied SIS in bone tissue engineering to enhance bone regeneration in animal models. However, the mechanism was rarely investigated. The aim of the current study was to investigate the osteoconductivity and osteoinductivity of SIS scaffold to bone regeneration systematically and the potential mechanism. Our results showed that SIS scaffold with excellent biocompatibility was beneficial for cell attachment, proliferation, migration and osteogenic differentiation of various cells contributing to bone repair. In mouse calvarial defect model, bone regeneration was significantly enhanced in the defects implanted with SIS scaffolds, along with the up-regulation of BMP-2 and CD31 expression. Accordingly, ID-1, the downstream target gene of BMPs, was increased in BMSCs cultured on SIS scaffolds. The results of this study suggest that SIS scaffold is a potential osteoconductive and osteoinductive biomaterial which plays multiple roles to various cells during process of bone regeneration. - Highlights: • SIS facilitates cell adhesion of BMSCs, osteoblasts and fibroblasts. • SIS promotes cell proliferation of osteoblasts and fibroblasts. • SIS promotes osteogenic differentiation of BMSCs and osteoblasts via BMP-2 pathway. • Synergistic effects of SIS to multiple cells enhance bone regeneration in vivo.

Small intestinal submucosa: A potential osteoconductive and osteoinductive biomaterial for bone tissue engineering

International Nuclear Information System (INIS)

Li, Mei; Zhang, Chi; Cheng, Mengjie; Gu, Qiaoqiao; Zhao, Jiyuan

2017-01-01

SIS is an acellular, naturally occurring collagenous extracellular matrix (ECM) material with various bioactive factors, which broadly applied in tissue engineering in clinic. Several studies have applied SIS in bone tissue engineering to enhance bone regeneration in animal models. However, the mechanism was rarely investigated. The aim of the current study was to investigate the osteoconductivity and osteoinductivity of SIS scaffold to bone regeneration systematically and the potential mechanism. Our results showed that SIS scaffold with excellent biocompatibility was beneficial for cell attachment, proliferation, migration and osteogenic differentiation of various cells contributing to bone repair. In mouse calvarial defect model, bone regeneration was significantly enhanced in the defects implanted with SIS scaffolds, along with the up-regulation of BMP-2 and CD31 expression. Accordingly, ID-1, the downstream target gene of BMPs, was increased in BMSCs cultured on SIS scaffolds. The results of this study suggest that SIS scaffold is a potential osteoconductive and osteoinductive biomaterial which plays multiple roles to various cells during process of bone regeneration. - Highlights: • SIS facilitates cell adhesion of BMSCs, osteoblasts and fibroblasts. • SIS promotes cell proliferation of osteoblasts and fibroblasts. • SIS promotes osteogenic differentiation of BMSCs and osteoblasts via BMP-2 pathway. • Synergistic effects of SIS to multiple cells enhance bone regeneration in vivo.

Congenital tracheal defects: embryonic development and animal models

Directory of Open Access Journals (Sweden)

Zenab Arooj Sher

2016-03-01

Full Text Available Tracheal anomalies are potentially catastrophic congenital defects. As a newborn begins to breathe, the trachea needs to maintain an appropriate balance of elasticity and rigidity. If the tracheal cartilages are disorganized or structurally weak, the airways can collapse, obstructing breathing. Cartilage rings that are too small or too rigid can also obstruct breathing. These anomalies are frequently associated with craniofacial syndromes, and, despite the importance, are poorly understood. In this review, we summarize the spectrum of pathological phenotypes of the trachea and correlate them with the molecular events uncovered in mouse models.

Lactation Defect in a Widely Used MMTV-Cre Transgenic Line of Mice

Science.gov (United States)

Yuan, Taichang; Wang, Yongping; Pao, Lily; Anderson, Steve M.; Gu, Haihua

2011-01-01

Background MMTV-Cre mouse lines have played important roles in our understanding about the functions of numerous genes in mouse mammary epithelial cells during mammary gland development and tumorigenesis. However, numerous studies have not included MMTV-Cre mice as controls, and many investigators have not indicated which of the different MMTV-Cre founder lines were used in their studies. Here, we describe a lactation defect that severely limits the use of one of the most commonly used MMTV-Cre founder lines. Methodology/Principal Findings To explore the role of protein tyrosine phosphatase Shp1 in mammary gland development, mice bearing the floxed Shp1 gene were crossed with MMTV-Cre mice and mammary gland development was examined by histological and biochemical techniques, while lactation competency was assessed by monitoring pup growth. Surprisingly, both the Shp1fl/+;MMTV-Cre and MMTV-Cre female mice displayed a severe lactation defect when compared to the Shp1 fl/+ control mice. Histological and biochemical analyses reveal that female mice expressing the MMTV-Cre transgene, either alone or in combination with floxed genes, exhibit defects in lobuloalveolar expansion, presence of large cytoplasmic lipid droplets in luminal alveolar epithelial cells postpartum, and precocious induction of involution. Using a PCR-based genotyping method, the three different founder lines can be distinguished, and we determined that the MMTV-Cre line A, the most widely used MMTV-Cre founder line, exhibits a profound lactation defect that limits its use in studies on mammary gland development. Conclusions/Significance The identification of a lactation defect in the MMTV-Cre line A mice indicates that investigators must use MMTV-Cre alone mice as control in studies that utilize Cre recombinase to excise genes of interest from mammary epithelial cells. Our results also suggest that previous results obtained in studies using the MMTV-Cre line A line should be re-evaluated if the

Potential Therapeutic Use of Relaxin in Healing Cranial Bone Defects

Science.gov (United States)

2017-09-01

to measure circulating concentrations of relaxin during the infusion by ELISA ; 3. sacrifice the mice at 10-12 days after cranial defect; 4. fix the...osmotic pump for 10-12 days, and to measure circulating concentrations of relaxin during the infusion by ELISA . Values of 0.35, 0.69, 1.61, 0.66, 1.99...vehicle-infused mice, because in our previous work, none was detected. This makes sense, because the ELISA we use does not detect mouse relaxin

The pathophysiology of mitochondrial disease as modeled in the mouse.

Science.gov (United States)

Wallace, Douglas C; Fan, Weiwei

2009-08-01

It is now clear that mitochondrial defects are associated with a plethora of clinical phenotypes in man and mouse. This is the result of the mitochondria's central role in energy production, reactive oxygen species (ROS) biology, and apoptosis, and because the mitochondrial genome consists of roughly 1500 genes distributed across the maternal mitochondrial DNA (mtDNA) and the Mendelian nuclear DNA (nDNA). While numerous pathogenic mutations in both mtDNA and nDNA mitochondrial genes have been identified in the past 21 years, the causal role of mitochondrial dysfunction in the common metabolic and degenerative diseases, cancer, and aging is still debated. However, the development of mice harboring mitochondrial gene mutations is permitting demonstration of the direct cause-and-effect relationship between mitochondrial dysfunction and disease. Mutations in nDNA-encoded mitochondrial genes involved in energy metabolism, antioxidant defenses, apoptosis via the mitochondrial permeability transition pore (mtPTP), mitochondrial fusion, and mtDNA biogenesis have already demonstrated the phenotypic importance of mitochondrial defects. These studies are being expanded by the recent development of procedures for introducing mtDNA mutations into the mouse. These studies are providing direct proof that mtDNA mutations are sufficient by themselves to generate major clinical phenotypes. As more different mtDNA types and mtDNA gene mutations are introduced into various mouse nDNA backgrounds, the potential functional role of mtDNA variation in permitting humans and mammals to adapt to different environments and in determining their predisposition to a wide array of diseases should be definitively demonstrated.

Histologic scoring of gastritis and gastric cancer in mouse models.

Science.gov (United States)

Rogers, Arlin B

2012-01-01

Histopathology is a defining endpoint in mouse models of experimental gastritis and gastric adenocarcinoma. Presented here is an overview of the histology of gastritis and gastric cancer in mice experimentally infected with Helicobacter pylori or H. felis. A modular histopathologic scoring scheme is provided that incorporates relevant disease-associated changes. Whereas the guide uses Helicobacter infection as the prototype challenge, features may be applied to chemical and genetically engineered mouse models of stomach cancer as well. Specific criteria included in the combined gastric histologic activity index (HAI) include inflammation, epithelial defects, oxyntic atrophy, hyperplasia, pseudopyloric metaplasia, and dysplasia or neoplasia. Representative photomicrographs accompany descriptions for each lesion grade. Differentiation of genuine tumor invasion from pseudoinvasion is highlighted. A brief comparison of normal rodent versus human stomach anatomy and physiology is accompanied by an introduction to mouse-specific lesions including mucous metaplasia and eosinophilic droplets (hyalinosis). In conjunction with qualified pathology support, this guide is intended to assist research scientists, postdoctoral fellows, graduate students, and medical professionals from affiliated disciplines in the interpretation and histologic grading of chronic gastritis and gastric carcinoma in mouse models.

Identification of 17 hearing impaired mouse strains in the TMGC ENU-mutagenesis screen

Energy Technology Data Exchange (ETDEWEB)

Kermany, Mohammad [St. Jude Children' s Research Hospital; Parker, Lisan [St. Jude Children' s Research Hospital; Guo, Yun-Kai [St. Jude Children' s Research Hospital; Miller, Darla R [ORNL; Swanson, Douglas J [ORNL; Yoo, Tai-June [Neuroscience Institute, Memphis, TN; Goldowitz, Daniel [University of Tennessee Health Science Center, Memphis; Zuo, Jian [St. Jude Children' s Research Hospital

2006-01-01

The Tennessee Mouse Genome Consortium (TMGC) employed an N-ethyl-N-nitrosourea (ENU)-mutagenesis scheme to identify mouse recessive mutants with hearing phenotypes. We employed auditory brainstem responses (ABR) to click and 8, 16, and 32 kHz stimuli and screened 285 pedigrees (1819 mice of 8-11 weeks old in various mixed genetic backgrounds) each bred to carry a homozygous ENU-induced mutation. To define mutant pedigrees, we measured P12 mice per pedigree in P2 generations and used a criterion where the mean ABR threshold per pedigree was two standard deviations above the mean of all offspring from the same parental strain. We thus identified 17 mutant pedigrees (6%), all exhibiting hearing loss at high frequencies (P16 kHz) with an average threshold elevation of 30-35 dB SPL. Interestingly, four mutants showed sex-biased hearing loss and six mutants displayed wide range frequency hearing loss. Temporal bone histology revealed that six of the first nine mutants displayed cochlear morphological defects: degeneration of spiral ganglia, spiral ligament fibrocytes or inner hair cells (but not outer hair cells) mostly in basal turns. In contrast to other ENU-mutagenesis auditory screens, our screen identified high-frequency, mild and sex-biased hearing defects. Further characterization of these 17 mouse models will advance our understanding of presbycusis and noise-induced hearing loss in humans.

Inhibition of HMG CoA reductase reveals an unexpected role for cholesterol during PGC migration in the mouse

Directory of Open Access Journals (Sweden)

Ewing Andrew G

2008-12-01

Full Text Available Abstract Background Primordial germ cells (PGCs are the embryonic precursors of the sperm and eggs. Environmental or genetic defects that alter PGC development can impair fertility or cause formation of germ cell tumors. Results We demonstrate a novel role for cholesterol during germ cell migration in mice. Cholesterol was measured in living tissue dissected from mouse embryos and was found to accumulate within the developing gonads as germ cells migrate to colonize these structures. Cholesterol synthesis was blocked in culture by inhibiting the activity of HMG CoA reductase (HMGCR resulting in germ cell survival and migration defects. These defects were rescued by co-addition of isoprenoids and cholesterol, but neither compound alone was sufficient. In contrast, loss of the last or penultimate enzyme in cholesterol biosynthesis did not alter PGC numbers or position in vivo. However embryos that lack these enzymes do not exhibit cholesterol defects at the stage at which PGCs are migrating. This demonstrates that during gestation, the cholesterol required for PGC migration can be supplied maternally. Conclusion In the mouse, cholesterol is required for PGC survival and motility. It may act cell-autonomously by regulating clustering of growth factor receptors within PGCs or non cell-autonomously by controlling release of growth factors required for PGC guidance and survival.

Stimulation of growth in the little mouse.

Science.gov (United States)

Beamer, W H; Eicher, E M

1976-10-01

The new mouse mutation little (lit) in the homozygous state causes a pituitary deficiency involving at least growth hormone (GH) and prolactin. The resultant growth failure of lit/lit mice was shown to be reversed by experimental conditions that enhanced levels of GH or GH and prolactin in the circulation. Two measures of growth, actual weight gain and bone dimension, were significantly improved by the physiological processes of pregnancy and pseudopregnancy, by extra-sellar graft of a normal mouse pituitary, and by treatment with GH but not prolactin. These data confirmed pituitary dysfunction as the basic defect caused by the mutation lit and showed that the GH deficiency is responsible for growth failure. However, the biological site of gene action, the pituitary or hypothalamus, has not been established. Little mice exhibit a number of characteristics similar to those of human genetic ateleotic dwarfism Type 1, namely genetic inheritance, time of onset of growth retardation, proportionate skeletal size reduction, and pituitary GH deficiency.

Insulin receptor internalization defect in an insulin-resistant mouse melanoma cell line

International Nuclear Information System (INIS)

Androlewicz, M.J.; Straus, D.S.; Brandenburg, D.F.

1989-01-01

Previous studies from this laboratory demonstrated that the PG19 mouse melanoma cell line does not exhibit a biological response to insulin, whereas melanoma x mouse embryo fibroblast hybrids do respond to insulin. To investigate the molecular basis of the insulin resistance of the PG19 melanoma cells, insulin receptors from the insulin-resistant melanoma cells and insulin-sensitive fibroblast x melanoma hybrid cells were analyzed by the technique of photoaffinity labeling using the photoprobe 125 I-NAPA-DP-insulin. Photolabeled insulin receptors from the two cell types have identical molecular weights as determined by SDS gel electrophoresis under reducing and nonreducing conditions, indicating that the receptors on the two cell lines are structurally similar. Insulin receptor internalization studies revealed that the hybrid cells internalize receptors to a high degree at 37 degree C, whereas the melanoma cells internalize receptors to a very low degree or not at all. The correlation between ability to internalize insulin receptors and sensitivity to insulin action in this system suggests that uptake of the insulin-receptor complex may be required for insulin action in these cells. Insulin receptors from the two cell lines autophosphorylate in a similar insulin-dependent manner both in vitro and in intact cells, indicating that insulin receptors on the melanoma and hybrid cells have functional tyrosine protein kinase activity. Therefore, the block in insulin action in the PG19 melanoma cells appears to reside at a step beyond insulin-stimulated receptor autophosphorylation

Histopathological Defects in Intestine in Severe Spinal Muscular Atrophy Mice Are Improved by Systemic Antisense Oligonucleotide Treatment.

Directory of Open Access Journals (Sweden)

Palittiya Sintusek

Full Text Available Gastrointestinal (GI defects, including gastroesophageal reflux, constipation and delayed gastric emptying, are common in patients with spinal muscular atrophy (SMA. Similar GI dysmotility has been identified in mouse models with survival of motor neuron (SMN protein deficiency. We previously described vascular defects in skeletal muscle and spinal cord of SMA mice and we hypothesized that similar defects could be involved in the GI pathology observed in these mice. We therefore investigated the gross anatomical structure, enteric vasculature and neurons in the small intestine in a severe mouse model of SMA. We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON designed to increase SMN protein expression. Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice. After systemic AON treatment in neonatal mice, all the abnormalities observed were significantly restored to near-normal levels. We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON. This study on the histopathological changes in the gastrointestinal system in severe SMA mice provides further indication of the complex role that SMN plays in multiple tissues and suggests that at least in SMA mice restoration of SMN production in peripheral tissues is essential for optimal outcome.

Histopathological Defects in Intestine in Severe Spinal Muscular Atrophy Mice Are Improved by Systemic Antisense Oligonucleotide Treatment

Science.gov (United States)

Sintusek, Palittiya; Catapano, Francesco; Angkathunkayul, Napat; Marrosu, Elena; Parson, Simon H.; Morgan, Jennifer E.; Muntoni, Francesco; Zhou, Haiyan

2016-01-01

Gastrointestinal (GI) defects, including gastroesophageal reflux, constipation and delayed gastric emptying, are common in patients with spinal muscular atrophy (SMA). Similar GI dysmotility has been identified in mouse models with survival of motor neuron (SMN) protein deficiency. We previously described vascular defects in skeletal muscle and spinal cord of SMA mice and we hypothesized that similar defects could be involved in the GI pathology observed in these mice. We therefore investigated the gross anatomical structure, enteric vasculature and neurons in the small intestine in a severe mouse model of SMA. We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression. Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice. After systemic AON treatment in neonatal mice, all the abnormalities observed were significantly restored to near-normal levels. We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON. This study on the histopathological changes in the gastrointestinal system in severe SMA mice provides further indication of the complex role that SMN plays in multiple tissues and suggests that at least in SMA mice restoration of SMN production in peripheral tissues is essential for optimal outcome. PMID:27163330

FETAL ALCOHOL SYNDROME IN FETUS OF MOUSE

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B. Nasrollahzadeh

1997-07-01

Full Text Available litis study is based on embryotoxic effects of ethanol on embryos and discussing the morphologic and hhtahtgic changes and defects an mouse. Tlie female animals were divided in three groups. Hie first group untreated as a control group but the second and third group received 10% and 20% solutions of ethanol respectively. Animals get use to certain level of ethanol solution and in the 10th day, the pregnancy period has been started. Then on the 19th day of gestation, the embryos were taken out from their mother's uterus and were examined for morphologic, histologic and skeletal disorders. In the first examination, the major defect was weight and length reduction in the second and third groups. these deffects, were severe in the second group in compare to third group that might be related to little consumption of the ethanol solution, due to bitter taste. In conclusion the teratogenic effect of alcohol on skeleton and joint is clear.

Anaerobic respiration of Escherichia coli in the mouse intestine.

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Jones, Shari A; Gibson, Terri; Maltby, Rosalie C; Chowdhury, Fatema Z; Stewart, Valley; Cohen, Paul S; Conway, Tyrrell

2011-10-01

The intestine is inhabited by a large microbial community consisting primarily of anaerobes and, to a lesser extent, facultative anaerobes, such as Escherichia coli, which we have shown requires aerobic respiration to compete successfully in the mouse intestine (S. A. Jones et al., Infect. Immun. 75:4891-4899, 2007). If facultative anaerobes efficiently lower oxygen availability in the intestine, then their sustained growth must also depend on anaerobic metabolism. In support of this idea, mutants lacking nitrate reductase or fumarate reductase have extreme colonization defects. Here, we further explore the role of anaerobic respiration in colonization using the streptomycin-treated mouse model. We found that respiratory electron flow is primarily via the naphthoquinones, which pass electrons to cytochrome bd oxidase and the anaerobic terminal reductases. We found that E. coli uses nitrate and fumarate in the intestine, but not nitrite, dimethyl sulfoxide, or trimethylamine N-oxide. Competitive colonizations revealed that cytochrome bd oxidase is more advantageous than nitrate reductase or fumarate reductase. Strains lacking nitrate reductase outcompeted fumarate reductase mutants once the nitrate concentration in cecal mucus reached submillimolar levels, indicating that fumarate is the more important anaerobic electron acceptor in the intestine because nitrate is limiting. Since nitrate is highest in the absence of E. coli, we conclude that E. coli is the only bacterium in the streptomycin-treated mouse large intestine that respires nitrate. Lastly, we demonstrated that a mutant lacking the NarXL regulator (activator of the NarG system), but not a mutant lacking the NarP-NarQ regulator, has a colonization defect, consistent with the advantage provided by NarG. The emerging picture is one in which gene regulation is tuned to balance expression of the terminal reductases that E. coli uses to maximize its competitiveness and achieve the highest possible population in

Novel Models to Study Effect of High-Altitude Hypoxic Exposure and Placental Insufficiency on Fetal Oxygen Metabolism and Congenital Heart Defects

Science.gov (United States)

2017-10-01

Metabolism and Congenital Heart Defects PRINCIPAL INVESTIGATOR: Steven Fisher, MD RECIPIENT: University of Maryland, Baltimore REPORT DATE...examined in fetal heart vs other tissues. Pregnant ODD-Luc dams age 3-6 months will inhale O2 concentrations ranging from 8-21% O2 x 4 h...Congenital Heart Defects in at-risk pregnancies. The first objective was to use a novel reporter of O2 concentrations, the ODDLuc mouse, to determine the

Neonatal Death and Heart Failure in Mouse with Transgenic HSP60 Expression

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Tsung-Hsien Chen

2015-01-01

Full Text Available Mitochondrial heat shock proteins, such as HSP60, are chaperones responsible for the folding, transport, and quality control of mitochondrial matrix proteins and are essential for maintaining life. Both prosurvival and proapoptotic roles have been proposed for HSP60, and HSP60 is reportedly involved in the initiation of autoimmune, metabolic, and cardiovascular diseases. The role of HSP60 in pathogenesis of these diseases remains unclear, partly because of the lack of mouse models expressing HSP60. In this study we generated HSP60 conditional transgenic mice suitable for investigating in vivo outcomes by expressing HSP60 at the targeted organ in disease models. Ubiquitous HSP60 induction in the embryonic stage caused neonatal death in mice at postnatal day 1. A high incidence of atrial septal defects was observed in HSP60-expressing mice, with increased apoptosis and myocyte degeneration that possibly contributed to massive hemorrhage and sponge-like cardiac muscles. Our results showed that neonatal heart failure through HSP60 induction likely involves developmental defects and excessive apoptosis. The conditional HSP60 mouse model is useful for studying crucial biological questions concerning HSP60.

Separating genetic and hemodynamic defects in neuropilin 1 knockout embryos.

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Jones, Elizabeth A V; Yuan, Li; Breant, Christine; Watts, Ryan J; Eichmann, Anne

2008-08-01

Targeted inactivation of genes involved in murine cardiovascular development frequently leads to abnormalities in blood flow. As blood fluid dynamics play a crucial role in shaping vessel morphology, the presence of flow defects generally prohibits the precise assignment of the role of the mutated gene product in the vasculature. In this study, we show how to distinguish between genetic defects caused by targeted inactivation of the neuropilin 1 (Nrp1) receptor and hemodynamic defects occurring in homozygous knockout embryos. Our analysis of a Nrp1 null allele bred onto a C57BL/6 background shows that vessel remodeling defects occur concomitantly with the onset of blood flow and cause death of homozygous mutants at E10.5. Using mouse embryo culture, we establish that hemodynamic defects are already present at E8.5 and continuous circulation is never established in homozygous mutants. The geometry of yolk sac blood vessels is altered and remodeling into yolk sac arteries and veins does not occur. To separate flow-induced deficiencies from those caused by the Nrp1 mutation, we arrested blood flow in cultured wild-type and mutant embryos and followed their vascular development. We find that loss of Nrp1 function rather than flow induces the altered geometry of the capillary plexus. Endothelial cell migration, but not replication, is altered in Nrp1 mutants. Gene expression analysis of endothelial cells isolated from freshly dissected wild-type and mutants and after culture in no-flow conditions showed down-regulation of the arterial marker genes connexin 40 and ephrin B2 related to the loss of Nrp1 function. This method allows genetic defects caused by loss-of-function of a gene important for cardiovascular development to be isolated even in the presence of hemodynamic defects.

Defects and defect processes in nonmetallic solids

CERN Document Server

Hayes, W

2004-01-01

This extensive survey covers defects in nonmetals, emphasizing point defects and point-defect processes. It encompasses electronic, vibrational, and optical properties of defective solids, plus dislocations and grain boundaries. 1985 edition.

Reciprocal mouse and human limb phenotypes caused by gain- and loss-of-function mutations affecting Lmbr1.

OpenAIRE

Clark, R M; Marker, P C; Roessler, E; Dutra, A; Schimenti, J C; Muenke, M; Kingsley, D M

2001-01-01

The major locus for dominant preaxial polydactyly in humans has been mapped to 7q36. In mice the dominant Hemimelic extra toes (Hx) and Hammertoe (Hm) mutations map to a homologous chromosomal region and cause similar limb defects. The Lmbr1 gene is entirely within the small critical intervals recently defined for both the mouse and human mutations and is misexpressed at the exact time that the mouse Hx phenotype becomes apparent during limb development. This result suggests that Lmbr1 may un...

Establishment of a new pull-out strength testing method to quantify early osseointegration-An experimental pilot study.

Science.gov (United States)

Nonhoff, J; Moest, T; Schmitt, Christian Martin; Weisel, T; Bauer, S; Schlegel, K A

2015-12-01

The animal study aims to evaluate a new experimental model for measuring sole the influence of the surface characteristics independent from implant macro-design on the level of osseointegration by registering the pull-out strength needed for removal of experimental devices with different surfaces from artificial defects. Seventy-two test bodies (36 with the FRIADENT(®) plus surface, 36 with the P15/HAp biofunctionalized surface) were inserted in six adult domestic pigs with artificial calvarial defects. The experimental devices were designed to fit in the defects leaving a gap between the test body and the local bone. After 21 days of healing, the animals were sacrificed and the test bodies were pulled out with a standardised reproducible pull-out device measuring the pull-out strength. The pull-out strength for both groups was compared. Twenty-one days after insertion a mean force of 412 ± 142 N for the P15/HAp group and 183 ± 105 N for the FRIADENT(®) plus group was measured for the removal of the specimens from the calvarial bone. The difference between the groups was statistically significant (p implant surfaces on the early stage of osseointegration. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

The Phospholipase D2 Knock Out Mouse Has Ectopic Purkinje Cells and Suffers from Early Adult-Onset Anosmia.

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Matthieu M Vermeren

Full Text Available Phospholipase D2 (PLD2 is an enzyme that produces phosphatidic acid (PA, a lipid messenger molecule involved in a number of cellular events including, through its membrane curvature properties, endocytosis. The PLD2 knock out (PLD2KO mouse has been previously reported to be protected from insult in a model of Alzheimer's disease. We have further analysed a PLD2KO mouse using mass spectrophotometry of its lipids and found significant differences in PA species throughout its brain. We have examined the expression pattern of PLD2 which allowed us to define which region of the brain to analyse for defect, notably PLD2 was not detected in glial-rich regions. The expression pattern lead us to specifically examine the mitral cells of olfactory bulbs, the Cornus Amonis (CA regions of the hippocampus and the Purkinje cells of the cerebellum. We find that the change to longer PA species correlates with subtle architectural defect in the cerebellum, exemplified by ectopic Purkinje cells and an adult-onset deficit of olfaction. These observations draw parallels to defects in the reelin heterozygote as well as the effect of high fat diet on olfaction.

Isoproterenol Increases RANKL Expression in a ATF4/NFATc1-Dependent Manner in Mouse Osteoblastic Cells

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Kyunghwa Baek

2017-10-01

Full Text Available Sympathetic nervous system stimulation-induced β-adrenergic signal transduction is known to induce bone loss and increase of osteoclast activity. Although isoproterenol, a nonspecific β-adrenergic receptor agonist, has been shown to increase receptor activator of NF-κB ligand (RANKL, the details of the regulatory mechanisms remain unclear. In the present study, we investigated the role of the nuclear factor of activated T-cells (NFAT in isoproterenol-induced RANKL expression in C2C12 and in primary cultured mouse calvarial cells. Isoproterenol increased nuclear factor of activated T-cells cytoplasmic 1 (NFATc1 and RANKL expressions at both mRNA and protein levels and increased NFAT reporter activity. NFATc1 knockdown blocked isoproterenol-mediated RANKL expression. Isoproterenol also promoted cAMP response element-binding protein 1 (CREB1 and activating transcription factor 4 (ATF4 phosphorylation. Isoproterenol-mediated transcriptional activation of NFAT was blocked by protein kinase A (PKA inhibitor H89. Isoproterenol-induced CREB1, ATF4, NFATc1, and RANKL expressions were suppressed by H89. Mutations in cAMP response element-like or NFAT-binding element suppressed isoproterenol-induced RANKL promoter activity. Chromatin immunoprecipitation analysis demonstrated that isoproterenol increased NFAT-binding and ATF4-binding activities on the mouse RANKL promoter, but did not increase CREB1-binding activity. Association of NFATc1 and ATF4 was not observed in a co-immunoprecipitation study. ATF4 knockdown suppressed isoproterenol-induced NFAT binding to the RANKL promoter, whereas NFATc1 knockdown did not suppress isoproterenol-induced ATF4 binding to the RANKL promoter. ATF4 knockdown suppressed isoproterenol-induced expressions of NFATc1 and RANKL. These results suggest that isoproterenol increases RANKL expression in an ATF4/NFATc1-dependent manner.

Human and murine very small embryonic-like cells represent multipotent tissue progenitors, in vitro and in vivo.

Science.gov (United States)

Havens, Aaron M; Sun, Hongli; Shiozawa, Yusuke; Jung, Younghun; Wang, Jingcheng; Mishra, Anjali; Jiang, Yajuan; O'Neill, David W; Krebsbach, Paul H; Rodgerson, Denis O; Taichman, Russell S

2014-04-01

The purpose of this study was to determine the lineage progression of human and murine very small embryonic-like (HuVSEL or MuVSEL) cells in vitro and in vivo. In vitro, HuVSEL and MuVSEL cells differentiated into cells of all three embryonic germ layers. HuVSEL cells produced robust mineralized tissue of human origin compared with controls in calvarial defects. Immunohistochemistry demonstrated that the HuVSEL cells gave rise to neurons, adipocytes, chondrocytes, and osteoblasts within the calvarial defects. MuVSEL cells were also able to differentiate into similar lineages. First round serial transplants of MuVSEL cells into irradiated osseous sites demonstrated that ∼60% of the cells maintained their VSEL cell phenotype while other cells differentiated into multiple tissues at 3 months. Secondary transplants did not identify donor VSEL cells, suggesting limited self renewal but did demonstrate VSEL cell derivatives in situ for up to 1 year. At no point were teratomas identified. These studies show that VSEL cells produce multiple cellular structures in vivo and in vitro and lay the foundation for future cell-based regenerative therapies for osseous, neural, and connective tissue disorders.

Safety Evaluation of a Bioglass–Polylactic Acid Composite Scaffold Seeded with Progenitor Cells in a Rat Skull Critical-Size Bone Defect

Science.gov (United States)

El-Kady, Abeer M.; Arbid, Mahmoud S.; Abd El-Hady, Bothaina M.; Marzi, Ingo; Seebach, Caroline

2014-01-01

Treating large bone defects represents a major challenge in traumatic and orthopedic surgery. Bone tissue engineering provides a promising therapeutic option to improve the local bone healing response. In the present study tissue biocompatibility, systemic toxicity and tumorigenicity of a newly developed composite material consisting of polylactic acid (PLA) and 20% or 40% bioglass (BG20 and BG40), respectively, were analyzed. These materials were seeded with mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) and tested in a rat calvarial critical size defect model for 3 months and compared to a scaffold consisting only of PLA. Serum was analyzed for organ damage markers such as GOT and creatinine. Leukocyte count, temperature and free radical indicators were measured to determine the degree of systemic inflammation. Possible tumor occurrence was assessed macroscopically and histologically in slides of liver, kidney and spleen. Furthermore, the concentrations of serum malondialdehyde (MDA) and sodium oxide dismutase (SOD) were assessed as indicators of tumor progression. Qualitative tissue response towards the implants and new bone mass formation was histologically investigated. BG20 and BG40, with or without progenitor cells, did not cause organ damage, long-term systemic inflammatory reactions or tumor formation. BG20 and BG40 supported bone formation, which was further enhanced in the presence of EPCs and MSCs. This investigation reflects good biocompatibility of the biomaterials BG20 and BG40 and provides evidence that additionally seeding EPCs and MSCs onto the scaffold does not induce tumor formation. PMID:24498345

The phenotype of FancB-mutant mouse embryonic stem cells

OpenAIRE

Kim, Tae Moon; Ko, Jun Ho; Choi, Yong Jun; Hu, Lingchuan; Hasty, Paul

2011-01-01

Fanconi anemia (FA) is a rare autosomal recessive disease characterized by bone marrow failure, developmental defects and cancer. There are multiple FA genes that enable the repair of interstrand crosslinks (ICLs) in coordination with a variety of other DNA repair pathways in a way that is poorly understood. Here we present the phenotype of mouse embryonic stem (ES) cells mutated for FancB. We found FancB-mutant cells exhibited reduced cellular proliferation, hypersensitivity to the crosslink...

Biology and therapy of inherited retinal degenerative disease: insights from mouse models

Science.gov (United States)

Veleri, Shobi; Lazar, Csilla H.; Chang, Bo; Sieving, Paul A.; Banin, Eyal; Swaroop, Anand

2015-01-01

Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases. PMID:25650393

Proinsulin atypical maturation and disposal induces extensive defects in mouse Ins2+/Akita β-cells.

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Qingxin Yuan

Full Text Available Because of its low relative folding rate and plentiful manufacture in β-cells, proinsulin maintains a homeostatic balance of natively and plentiful non-natively folded states (i.e., proinsulin homeostasis, PIHO through the integration of maturation and disposal processes. PIHO is susceptible to genetic and environmental influences, and its disorder has been critically linked to defects in β-cells in diabetes. To explore this hypothesis, we performed polymerase chain reaction (PCR, metabolic-labeling, immunoblotting, and histological studies to clarify what defects result from primary disorder of PIHO in model Ins2(+/Akita β-cells. We used T antigen-transformed Ins2(+/Akita and control Ins2(+/+ β-cells established from Akita and wild-type littermate mice. In Ins2(+/Akita β-cells, we found no apparent defect at the transcriptional and translational levels to contribute to reduced cellular content of insulin and its precursor and secreted insulin. Glucose response remained normal in proinsulin biosynthesis but was impaired for insulin secretion. The size and number of mature insulin granules were reduced, but the size/number of endoplasmic reticulum, Golgi, mitochondrion, and lysosome organelles and vacuoles were expanded/increased. Moreover, cell death increased, and severe oxidative stress, which manifested as increased reactive oxygen species, thioredoxin-interacting protein, and protein tyrosine nitration, occurred in Ins2(+/Akita β-cells and/or islets. These data show the first clear evidence that primary PIHO imbalance induces severe oxidative stress and impairs glucose-stimulated insulin release and β-cell survival as well as producing other toxic consequences. The defects disclosed/clarified in model Ins2(+/Akita β-cells further support a role of the genetic and stress-susceptible PIHO disorder in β-cell failure and diabetes.

Defective homing is associated with altered Cdc42 activity in cells from patients with Fanconi anemia group A

Science.gov (United States)

Zhang, Xiaoling; Shang, Xun; Guo, Fukun; Murphy, Kim; Kirby, Michelle; Kelly, Patrick; Reeves, Lilith; Smith, Franklin O.; Williams, David A.

2008-01-01

Previous studies showed that Fanconi anemia (FA) murine stem cells have defective reconstitution after bone marrow (BM) transplantation. The mechanism underlying this defect is not known. Here, we report defective homing of FA patient BM progenitors transplanted into mouse models. Using cells from patients carrying mutations in FA complementation group A (FA-A), we show that when transplanted into nonobese diabetic/severe combined immunodeficiency (NOD/SCID) recipient mice, FA-A BM cells exhibited impaired homing activity. FA-A cells also showed defects in both cell-cell and cell-matrix adhesion. Complementation of FA-A deficiency by reexpression of FANCA readily restored adhesion of FA-A cells. A significant decrease in the activity of the Rho GTPase Cdc42 was found associated with these defective functions in patient-derived cells, and expression of a constitutively active Cdc42 mutant was able to rescue the adhesion defect of FA-A cells. These results provide the first evidence that FA proteins influence human BM progenitor homing and adhesion via the small GTPase Cdc42-regulated signaling pathway. PMID:18565850

Functional studies of signaling pathways in peri-implantation development of the mouse embryo by RNAi

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Bell Graham

2005-12-01

Full Text Available Abstract Background Studies of gene function in the mouse have relied mainly on gene targeting via homologous recombination. However, this approach is difficult to apply in specific windows of time, and to simultaneously knock-down multiple genes. Here we report an efficient method for dsRNA-mediated gene silencing in late cleavage-stage mouse embryos that permits examination of phenotypes at post-implantation stages. Results We show that introduction of Bmp4 dsRNA into intact blastocysts by electroporation recapitulates the genetic Bmp4 null phenotype at gastrulation. It also reveals a novel role for Bmp4 in the regulation the anterior visceral endoderm specific gene expression and its positioning. We also show that RNAi can be used to simultaneously target several genes. When applied to the three murine isoforms of Dishevelled, it leads to earlier defects than previously observed in double knock-outs. These include severe delays in post-implantation development and defects in the anterior midline and neural folds at headfold stages. Conclusion Our results indicate that the BMP4 signalling pathway contributes to the development of the anterior visceral endoderm, and reveal an early functional redundancy between the products of the murine Dishevelled genes. The proposed approach constitutes a powerful tool to screen the functions of genes that govern the development of the mouse embryo.

Cerebellar Expression of the Neurotrophin Receptor p75 in Naked-Ataxia Mutant Mouse

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Maryam Rahimi Balaei

2016-01-01

Full Text Available Spontaneous mutation in the lysosomal acid phosphatase 2 (Acp2 mouse (nax—naked-ataxia mutant mouse correlates with severe cerebellar defects including ataxia, reduced size and abnormal lobulation as well as Purkinje cell (Pc degeneration. Loss of Pcs in the nax cerebellum is compartmentalized and harmonized to the classic pattern of gene expression of the cerebellum in the wild type mouse. Usually, degeneration starts in the anterior and posterior zones and continues to the central and nodular zones of cerebellum. Studies have suggested that the p75 neurotrophin receptor (NTR plays a role in Pc degeneration; thus, in this study, we investigated the p75NTR pattern and protein expression in the cerebellum of the nax mutant mouse. Despite massive Pc degeneration that was observed in the nax mouse cerebellum, p75NTR pattern expression was similar to the HSP25 pattern in nax mice and comparable with wild type sibling cerebellum. In addition, immunoblot analysis of p75NTR protein expression did not show any significant difference between nax and wild type sibling (p > 0.5. In comparison with wild type counterparts, p75NTR pattern expression is aligned with the fundamental cytoarchitecture organization of the cerebellum and is unchanged in the nax mouse cerebellum despite the severe neurodevelopmental disorder accompanied with Pc degeneration.

Left-right asymmetry defect in the hippocampal circuitry impairs spatial learning and working memory in iv mice.

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Kazuhiro Goto

Full Text Available Although left-right (L-R asymmetry is a fundamental feature of higher-order brain function, little is known about how asymmetry defects of the brain affect animal behavior. Previously, we identified structural and functional asymmetries in the circuitry of the mouse hippocampus resulting from the asymmetrical distribution of NMDA receptor GluR ε2 (NR2B subunits. We further examined the ε2 asymmetry in the inversus viscerum (iv mouse, which has randomized laterality of internal organs, and found that the iv mouse hippocampus exhibits right isomerism (bilateral right-sidedness in the synaptic distribution of the ε2 subunit, irrespective of the laterality of visceral organs. To investigate the effects of hippocampal laterality defects on higher-order brain functions, we examined the capacity of reference and working memories of iv mice using a dry maze and a delayed nonmatching-to-position (DNMTP task, respectively. The iv mice improved dry maze performance more slowly than control mice during acquisition, whereas the asymptotic level of performance was similar between the two groups. In the DNMTP task, the iv mice showed poorer accuracy than control mice as the retention interval became longer. These results suggest that the L-R asymmetry of hippocampal circuitry is critical for the acquisition of reference memory and the retention of working memory.

Progressive Impairment of Lactate-based Gluconeogenesis in the Huntington's Disease Mouse Model R6/2.

Science.gov (United States)

Nielsen, Signe Marie Borch; Hasholt, Lis; Nørremølle, Anne; Josefsen, Knud

2015-04-20

Huntington's disease (HD) is a neurodegenerative illness, where selective neuronal loss in the brain caused by expression of mutant huntingtin protein leads to motor dysfunction and cognitive decline in addition to peripheral metabolic changes. In this study we confirm our previous observation of impairment of lactate-based hepatic gluconeogenesis in the transgenic HD mouse model R6/2 and determine that the defect manifests very early and progresses in severity with disease development, indicating a potential to explore this defect in a biomarker context. Moreover, R6/2 animals displayed lower blood glucose levels during prolonged fasting compared to wild type animals.

Cloning, characterization and targeting of the mouse HEXA gene

Energy Technology Data Exchange (ETDEWEB)

Wakamatsu, N.; Trasler, J.M.; Gravel, R.A. [McGill Univ., Quebec (Canada)] [and others

1994-09-01

The HEXA gene, encoding the {alpha} subunit of {beta}-hexosaminidase A, is essential for the metabolism of ganglioside G{sub M2}, and defects in this gene cause Tay-Sachs disease in humans. To elucidate the role of the gene in the nervous system of the mouse and to establish a mouse model of Tay-Sachs disease, we have cloned and characterized the HEXA gene and targeted a disruption of the gene in mouse ES cells. The mouse HEXA gene spans {approximately}26 kb and consists of 14 exons, similar to the human gene. A heterogeneous transcription initiation site was identified 21-42 bp 5{prime} of the initiator ATG, with two of the sites fitting the consensus CTCA (A = start) as seen for some weak initiator systems. Promoter analysis showed that the first 150 bp 5{prime} of the ATG contained 85% of promoter activity observed in constructs containing up to 1050 bp of 5{prime} sequence. The active region contained a sequence matching that of the adenovirus major late promoter upstream element factor. A survey of mouse tissues showed that the highest mRNA levels were in (max to min): testis (5.5 x brain cortex), adrenal, epididymis, heart, brain, lung, kidney, and liver (0.3 x brain cortex). A 12 kb BstI/SalI fragment containing nine exons was disrupted with the insertion of the bacterial neo{sup r} gene in exon 11 and was targeted into 129/Sv ES cells by homologous recombination. Nine of 153 G418 resistant clones were correctly targeted as confirmed by Southern blotting. The heterozygous ES cells were microinjected into mouse blastocysts and implanted into pseudo-pregnant mice. Nine male chimeric mice, showing that 40-95% chimerism for the 129/Sv agouti coat color marker, are being bred in an effort to generate germline transmission of the disrupted HEXA gene.

Vascular defects and sensorineural deafness in a mouse model of Norrie disease.

Science.gov (United States)

Rehm, Heidi L; Zhang, Duan-Sun; Brown, M Christian; Burgess, Barbara; Halpin, Chris; Berger, Wolfgang; Morton, Cynthia C; Corey, David P; Chen, Zheng-Yi

2002-06-01

Norrie disease is an X-linked recessive syndrome of blindness, deafness, and mental retardation. A knock-out mouse model with an Ndp gene disruption was studied. We examined the hearing phenotype, including audiological, histological, and vascular evaluations. As is seen in humans, the mice had progressive hearing loss leading to profound deafness. The primary lesion was localized to the stria vascularis, which houses the main vasculature of the cochlea. Fluorescent dyes showed an abnormal vasculature in this region and eventual loss of two-thirds of the vessels. We propose that one of the principal functions of norrin in the ear is to regulate the interaction of the cochlea with its vasculature.

Transgenic Expression of Constitutively Active RAC1 Disrupts Mouse Rod Morphogenesis

Science.gov (United States)

Song, Hongman; Bush, Ronald A.; Vijayasarathy, Camasamudram; Fariss, Robert N.; Kjellstrom, Sten; Sieving, Paul A.

2014-01-01

Purpose. Dominant-active RAC1 rescues photoreceptor structure in Drosophila rhodopsin-null mutants, indicating an important role in morphogenesis. This report assesses the morphogenetic effect of activated RAC1 during mammalian rod photoreceptor development using transgenic mice that express constitutively active (CA) RAC1. Methods. Transgenic mice were generated by expressing CA RAC1 under control of the Rhodopsin promoter, and morphological features of the photoreceptors were evaluated by histology, immunohistochemistry, and transmission electron microscopy. Function was evaluated by electroretinography. Potential protein partners of CA RAC1 were identified by co-immunoprecipitation of retinal extracts. Results. Constitutively active RAC1 expression in differentiating rods disrupted outer retinal lamination as early as postnatal day (P)6, and many photoreceptor cell nuclei were displaced apically into the presumptive subretinal space. These photoreceptors did not develop normal inner and outer segments and had abnormal placement of synaptic elements. Some photoreceptor nuclei were also mislocalized into the inner nuclear layer. Extensive photoreceptor degeneration was subsequently observed in the adult animal. Constitutively active RAC1 formed a complex with the polarity protein PAR6 and with microtubule motor dynein in mouse retina. The normal localization of the PAR6 complex was disrupted in CA RAC1-expressing rod photoreceptors. Conclusions. Constitutively active RAC1 had a profound negative effect on mouse rod cell viability and development. Rod photoreceptors in the CA RAC1 retina exhibited a defect in polarity and migration. Constitutively active RAC1 disrupted rod morphogenesis and gave a phenotype resembling that found in the Crumbs mutant. PAR6 and dynein are two potential downstream effectors that may be involved in CA RAC1-mediated defective mouse photoreceptor morphogenesis. PMID:24651551

Solitary Giant Neurofibroma of the Scalp with Calvarial Defect in a ...

African Journals Online (AJOL)

2010-06-29

Jun 29, 2010 ... Neurosurgery and 1Department of Pathology, Usmanu Dan. Fodiyo University, Teaching Hospital Sokoto, Nigeria. Address for correspondence: Dr. N. J. Ismail, Department of. Neurosurgery, Regional Center for Neurosurgery, Usmanu ... with complete tumor excision, and frontal cranioplasty with antibiotic ...

An antibiotic-responsive mouse model of fulminant ulcerative colitis.

Directory of Open Access Journals (Sweden)

Silvia S Kang

2008-03-01

Full Text Available BACKGROUND: The constellation of human inflammatory bowel disease (IBD includes ulcerative colitis and Crohn's disease, which both display a wide spectrum in the severity of pathology. One theory is that multiple genetic hits to the host immune system may contribute to the susceptibility and severity of IBD. However, experimental proof of this concept is still lacking. Several genetic mouse models that each recapitulate some aspects of human IBD have utilized a single gene defect to induce colitis. However, none have produced pathology clearly distinguishable as either ulcerative colitis or Crohn's disease, in part because none of them reproduce the most severe forms of disease that are observed in human patients. This lack of severe IBD models has posed a challenge for research into pathogenic mechanisms and development of new treatments. We hypothesized that multiple genetic hits to the regulatory machinery that normally inhibits immune activation in the intestine would generate more severe, reproducible pathology that would mimic either ulcerative colitis or Crohn's disease. METHODS AND FINDINGS: We generated a novel mouse line (dnKO that possessed defects in both TGFbetaRII and IL-10R2 signaling. These mice rapidly and reproducibly developed a disease resembling fulminant human ulcerative colitis that was quite distinct from the much longer and more variable course of pathology observed previously in mice possessing only single defects. Pathogenesis was driven by uncontrolled production of proinflammatory cytokines resulting in large part from T cell activation. The disease process could be significantly ameliorated by administration of antibodies against IFNgamma and TNFalpha and was completely inhibited by a combination of broad-spectrum antibiotics. CONCLUSIONS: Here, we develop to our knowledge the first mouse model of fulminant ulcerative colitis by combining multiple genetic hits in immune regulation and demonstrate that the resulting

Bone regeneration potential of stem cells derived from periodontal ligament or gingival tissue sources encapsulated in RGD-modified alginate scaffold.

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Moshaverinia, Alireza; Chen, Chider; Xu, Xingtian; Akiyama, Kentaro; Ansari, Sahar; Zadeh, Homayoun H; Shi, Songtao

2014-02-01

Mesenchymal stem cells (MSCs) provide an advantageous alternative therapeutic option for bone regeneration in comparison to current treatment modalities. However, delivering MSCs to the defect site while maintaining a high MSC survival rate is still a critical challenge in MSC-mediated bone regeneration. Here, we tested the bone regeneration capacity of periodontal ligament stem cells (PDLSCs) and gingival mesenchymal stem cells (GMSCs) encapsulated in a novel RGD- (arginine-glycine-aspartic acid tripeptide) coupled alginate microencapsulation system in vitro and in vivo. Five-millimeter-diameter critical-size calvarial defects were created in immunocompromised mice and PDLSCs and GMSCs encapsulated in RGD-modified alginate microspheres were transplanted into the defect sites. New bone formation was assessed using microcomputed tomography and histological analyses 8 weeks after transplantation. Results confirmed that our microencapsulation system significantly enhanced MSC viability and osteogenic differentiation in vitro compared with non-RGD-containing alginate hydrogel microspheres with larger diameters. Results confirmed that PDLSCs were able to repair the calvarial defects by promoting the formation of mineralized tissue, while GMSCs showed significantly lower osteogenic differentiation capability. Further, results revealed that RGD-coupled alginate scaffold facilitated the differentiation of oral MSCs toward an osteoblast lineage in vitro and in vivo, as assessed by expression of osteogenic markers Runx2, ALP, and osteocalcin. In conclusion, these results for the first time demonstrated that MSCs derived from orofacial tissue encapsulated in RGD-modified alginate scaffold show promise for craniofacial bone regeneration. This treatment modality has many potential dental and orthopedic applications.

Neural tube defects – recent advances, unsolved questions and controversies

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Copp, Andrew J.; Stanier, Philip; Greene, Nicholas D. E.

2014-01-01

Neural tube defects (NTDs) are severe congenital malformations affecting around 1 in every 1000 pregnancies. Here we review recent advances and currently unsolved issues in the NTD field. An innovation in clinical management has come from the demonstration that closure of open spina bifida lesions in utero can diminish neurological dysfunction in children. Primary prevention by folic acid has been enhanced through introduction of mandatory food fortification in some countries, although not yet in UK. Genetic predisposition comprises the majority of NTD risk, and genes that regulate folate one-carbon metabolism and planar cell polarity have been strongly implicated. The sequence of human neural tube closure events remains controversial, but study of mouse NTD models shows that anencephaly, open spina bifida and craniorachischisis result from failure of primary neurulation, while skin-covered spinal dysraphism results from defective secondary neurulation. Other ‘NTD’ malformations, such as encephalocele, are likely to be post-neurulation disorders. PMID:23790957

Abnormal notochord branching is associated with foregut malformations in the adriamycin treated mouse model.

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Hajduk, Piotr; Sato, Hideaki; Puri, Prem; Murphy, Paula

2011-01-01

Oesophageal atresia (OA) and tracheooesophageal fistula (TOF) are relatively common human congenital malformations of the foregut where the oesophagus does not connect with the stomach and there is an abnormal connection between the stomach and the respiratory tract. They require immediate corrective surgery and have an impact on the future health of the individual. These abnormalities are mimicked by exposure of rat and mouse embryos in utero to the drug adriamycin. The causes of OA/TOF during human development are not known, however a number of mouse mutants where different signalling pathways are directly affected, show similar abnormalities, implicating multiple and complex signalling mechanisms. The similarities in developmental outcome seen in human infants and in the adriamycin treated mouse model underline the potential of this model to unravel the early embryological events and further our understanding of the processes disturbed, leading to such abnormalities. Here we report a systematic study of the foregut and adjacent tissues in embryos treated with adriamycin at E7 and E8 and analysed between E9 and E12, comparing morphology in 3D in 149 specimens. We describe a spectrum of 8 defects, the most common of which is ventral displacement and branching of the notochord (in 94% of embryos at E10) and a close spatial correspondence between the site of notochord branching and defects of the foregut. In addition gene expression analysis shows altered dorso-ventral foregut patterning in the vicinity of notochord branches. This study shows a number of features of the adriamycin mouse model not previously reported, implicates the notochord as a primary site of disturbance in such abnormalities and underlines the importance of the model to further address the mechanistic basis of foregut congenital abnormalities.

Embryonic Lethality of Mitochondrial Pyruvate Carrier 1 Deficient Mouse Can Be Rescued by a Ketogenic Diet

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Krznar, Petra; Hörl, Manuel; Ammar, Zeinab; Montessuit, Sylvie; Pierredon, Sandra; Zamboni, Nicola; Martinou, Jean-Claude

2016-01-01

Mitochondrial import of pyruvate by the mitochondrial pyruvate carrier (MPC) is a central step which links cytosolic and mitochondrial intermediary metabolism. To investigate the role of the MPC in mammalian physiology and development, we generated a mouse strain with complete loss of MPC1 expression. This resulted in embryonic lethality at around E13.5. Mouse embryonic fibroblasts (MEFs) derived from mutant mice displayed defective pyruvate-driven respiration as well as perturbed metabolic profiles, and both defects could be restored by reexpression of MPC1. Labeling experiments using 13C-labeled glucose and glutamine demonstrated that MPC deficiency causes increased glutaminolysis and reduced contribution of glucose-derived pyruvate to the TCA cycle. Morphological defects were observed in mutant embryonic brains, together with major alterations of their metabolome including lactic acidosis, diminished TCA cycle intermediates, energy deficit and a perturbed balance of neurotransmitters. Strikingly, these changes were reversed when the pregnant dams were fed a ketogenic diet, which provides acetyl-CoA directly to the TCA cycle and bypasses the need for a functional MPC. This allowed the normal gestation and development of MPC deficient pups, even though they all died within a few minutes post-delivery. This study establishes the MPC as a key player in regulating the metabolic state necessary for embryonic development, neurotransmitter balance and post-natal survival. PMID:27176894

Comparative mapping of DNA markers from the familial Alzheimer disease and Down syndrome regions of human chromosome 21 to mouse chromosomes 16 and 17

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Cheng, S.V.; Nadeau, J.H.; Tanzi, R.E.; Watkins, P.C.; Jagadesh, J.; Taylor, B.A.; Haines, J.L.; Sacchi, N.; Gusella, J.F. (Harvard Medical School, Boston, MA (USA))

1988-08-01

Mouse trisomy 16 has been proposed as an animal model of Down syndrome (DS), since this chromosome contains homologues of several loci from the q22 band of human chromosome 21. The recent mapping of the defect causing familial Alzheimer disease (FAD) and the locus encoding the Alzheimer amyloid {beta} precursor protein (APP) to human chromosome 21 has prompted a more detailed examination of the extent of conservation of this linkage group between the two species. Using anonymous DNA probes and cloned genes from human chromosome 21 in a combination of recombinant inbred and interspecific mouse backcross analyses, the authors have established that the linkage group shared by mouse chromosome 16 includes not only the critical DS region of human chromosome 21 but also the APP gene and FAD-linked markers. Extending from the anonymous DNA locus D21S52 to ETS2, the linkage map of six loci spans 39% recombination in man but only 6.4% recombination in the mouse. A break in synteny occurs distal to ETS2, with the homologue of the human marker D21S56 mapping to mouse chromosome 17. Conservation of the linkage relationships of markers in the FAD region suggests that the murine homologue of the FAD locus probably maps to chromosome 16 and that detailed comparison of the corresponding region in both species could facilitate identification of the primary defect in this disorder. The break in synteny between the terminal portion of human chromosome 21 and mouse chromosome 16 indicates, however, that mouse trisomy 16 may not represent a complete model of DS.

Comparative mapping of DNA markers from the familial Alzheimer disease and Down syndrome regions of human chromosome 21 to mouse chromosomes 16 and 17

International Nuclear Information System (INIS)

Cheng, S.V.; Nadeau, J.H.; Tanzi, R.E.; Watkins, P.C.; Jagadesh, J.; Taylor, B.A.; Haines, J.L.; Sacchi, N.; Gusella, J.F.

1988-01-01

Mouse trisomy 16 has been proposed as an animal model of Down syndrome (DS), since this chromosome contains homologues of several loci from the q22 band of human chromosome 21. The recent mapping of the defect causing familial Alzheimer disease (FAD) and the locus encoding the Alzheimer amyloid β precursor protein (APP) to human chromosome 21 has prompted a more detailed examination of the extent of conservation of this linkage group between the two species. Using anonymous DNA probes and cloned genes from human chromosome 21 in a combination of recombinant inbred and interspecific mouse backcross analyses, the authors have established that the linkage group shared by mouse chromosome 16 includes not only the critical DS region of human chromosome 21 but also the APP gene and FAD-linked markers. Extending from the anonymous DNA locus D21S52 to ETS2, the linkage map of six loci spans 39% recombination in man but only 6.4% recombination in the mouse. A break in synteny occurs distal to ETS2, with the homologue of the human marker D21S56 mapping to mouse chromosome 17. Conservation of the linkage relationships of markers in the FAD region suggests that the murine homologue of the FAD locus probably maps to chromosome 16 and that detailed comparison of the corresponding region in both species could facilitate identification of the primary defect in this disorder. The break in synteny between the terminal portion of human chromosome 21 and mouse chromosome 16 indicates, however, that mouse trisomy 16 may not represent a complete model of DS

The novel mouse mutant, chuzhoi, has disruption of Ptk7 protein and exhibits defects in neural tube, heart and lung development and abnormal planar cell polarity in the ear

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Paudyal Anju

2010-08-01

Full Text Available Abstract Background The planar cell polarity (PCP signalling pathway is fundamental to a number of key developmental events, including initiation of neural tube closure. Disruption of the PCP pathway causes the severe neural tube defect of craniorachischisis, in which almost the entire brain and spinal cord fails to close. Identification of mouse mutants with craniorachischisis has proven a powerful way of identifying molecules that are components or regulators of the PCP pathway. In addition, identification of an allelic series of mutants, including hypomorphs and neomorphs in addition to complete nulls, can provide novel genetic tools to help elucidate the function of the PCP proteins. Results We report the identification of a new N-ethyl-N-nitrosourea (ENU-induced mutant with craniorachischisis, which we have named chuzhoi (chz. We demonstrate that chuzhoi mutant embryos fail to undergo initiation of neural tube closure, and have characteristics consistent with defective convergent extension. These characteristics include a broadened midline and reduced rate of increase of their length-to-width ratio. In addition, we demonstrate disruption in the orientation of outer hair cells in the inner ear, and defects in heart and lung development in chuzhoi mutants. We demonstrate a genetic interaction between chuzhoi mutants and both Vangl2Lp and Celsr1Crsh mutants, strengthening the hypothesis that chuzhoi is involved in regulating the PCP pathway. We demonstrate that chuzhoi maps to Chromosome 17 and carries a splice site mutation in Ptk7. This mutation results in the insertion of three amino acids into the Ptk7 protein and causes disruption of Ptk7 protein expression in chuzhoi mutants. Conclusions The chuzhoi mutant provides an additional genetic resource to help investigate the developmental basis of several congenital abnormalities including neural tube, heart and lung defects and their relationship to disruption of PCP. The chuzhoi mutation

Biology and therapy of inherited retinal degenerative disease: insights from mouse models

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Shobi Veleri

2015-02-01

Full Text Available Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases.

Enzyme replacement prevents enamel defects in hypophosphatasia mice

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Yadav, Manisha C.; de Oliveira, Rodrigo Cardoso; Foster, Brian L.; Fong, Hanson; Cory, Esther; Narisawa, Sonoko; Sah, Robert L.; Somerman, Martha; Whyte, Michael P.; Millán, José Luis

2012-01-01

Hypophosphatasia (HPP) is the inborn error of metabolism characterized by deficiency of alkaline phosphatase activity leading to rickets or osteomalacia and to dental defects. HPP occurs from loss-of-function mutations within the gene that encodes the tissue-nonspecific isozyme of alkaline phosphatase (TNAP). TNAP knockout (Alpl−/−, a.k.a. Akp2−/−) mice closely phenocopy infantile HPP, including the rickets, vitamin B6-responsive seizures, improper dentin mineralization, and lack of acellular cementum. Here, we report that lack of TNAP in Alpl−/− mice also causes severe enamel defects, which are preventable by enzyme replacement with mineral-targeted TNAP (ENB-0040). Immunohistochemistry was used to map the spatiotemporal expression of TNAP in the tissues of the developing enamel organ of healthy mouse molars and incisors. We found strong, stage-specific expression of TNAP in ameloblasts. In the Alpl−/− mice, histological, μCT, and scanning electron microscopy analysis showed reduced mineralization and disrupted organization of the rods and inter-rod structures in enamel of both the molars and incisors. All of these abnormalities were prevented in mice receiving from birth daily subcutaneous injections of mineral-targeting, human TNAP (sALP-FcD10, a.k.a. ENB-0040) at 8.2 mg/kg/day for up to 44 days. These data reveal an important role for TNAP in enamel mineralization, and demonstrate the efficacy of mineral-targeted TNAP to prevent enamel defects in HPP. PMID:22461224

Immunization against Genital Herpes with a Vaccine Virus That has Defects in Productive and Latent Infection

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da Costa, Xavier J.; Jones, Cheryl A.; Knipe, David M.

1999-06-01

An effective vaccine for genital herpes has been difficult to achieve because of the limited efficacy of subunit vaccines and the safety concerns about live viruses. As an alternative approach, mutant herpes simplex virus strains that are replication-defective can induce protective immunity. To increase the level of safety and to prove that replication was not needed for immunization, we constructed a mutant herpes simplex virus 2 strain containing two deletion mutations, each of which eliminated viral replication. The double-mutant virus induces protective immunity that can reduce acute viral shedding and latent infection in a mouse genital model, but importantly, the double-mutant virus shows a phenotypic defect in latent infection. This herpes vaccine strain, which is immunogenic but has defects in both productive and latent infection, provides a paradigm for the design of vaccines and vaccine vectors for other sexually transmitted diseases, such as AIDS.

Functional antigen binding by the defective B cells of CBA/N mice.

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Snippe, H; Merchant, B; Lizzio, E F; Inman, J K

1982-01-01

CBA/N mice have an X-linked B cell defect which prevents them from responding to nonmitogenic thymic independent (TI-2) antigens such as dinitrophenylated DNP-Ficoll (1,2). The F1 male progeny of CBA/N female mice express the same defect. Spleen cell suspensions from such defective mice (CBA/N X C3H/HeN F1 males) could not respond to DNP-Ficoll following in vitro immunization and subsequent transfer into irradiated, syngeneic, F1 male recipients as expected. In contrast, normal CBA/N X C3H/HeN F1 female spleen cells could respond and effect a "rescue"; they mounted strong plaque-forming cell responses 7 days after in vitro exposure to DNP-Ficoll and subsequent transfer into irradiated F1 male recipients. Defective F1 male spleen cells, however, could bind significant quantities of 125I-DNP-Ficoll after in vitro exposure. Extensive washing of these spleen cells could not reverse this binding. Such DNP-Ficoll-exposed and washed F1 male spleen cells could, after transfer, aid normal untreated F1 female cells in their rescue function. The defective F1 male spleen cells could convey immunogenic quantities of DNP-Ficoll to the "rescuing" F1 female cells. Mitomycin treatment of F1 male cells did not interfere with their conveyor function. Goat anti-mouse mu serum impeded the passive antigen conveyor function of defective F1 male cells as did prior exposure to high concentrations of free DNP hapten. Our data support the view that the B cell defect of CBA/N X C3H/HeN F1 male mice does not relate to antigen binding, but rather to an inability to be effectively triggered by certain cell-bound polymeric antigens.

Novel de novo pathogenic variant in the NR2F2 gene in a boy with congenital heart defect and dysmorphic features.

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Upadia, Jariya; Gonzales, Patrick R; Robin, Nathaniel H

2018-04-16

The NR2F2 gene plays an important role in angiogenesis and heart development. Moreover, this gene is involved in organogenesis in many other organs in mouse models. Variants in this gene have been reported in a number of patients with nonsyndromic atrioventricular septal defect, and in one patient with congenital heart defect and dysmorphic features. Here we report an 11-month-old Caucasian male with global developmental delay, dysmorphic features, coarctation of the aorta, and ventricular septal defect. He was later found to have a pathogenic mutation in the NR2F2 gene by whole exome sequencing. This is the second instance in which an NR2F2 mutation has been identified in a child with a congenital heart defect and other anomalies. This case suggests that some variants in NR2F2 may cause syndromic forms of congenital heart defect. © 2018 Wiley Periodicals, Inc.

Mechanisms of PD-L1/PD-1-mediated CD8 T-cell dysfunction in the context of aging-related immune defects in the Eµ-TCL1 CLL mouse model.

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McClanahan, Fabienne; Riches, John C; Miller, Shaun; Day, William P; Kotsiou, Eleni; Neuberg, Donna; Croce, Carlo M; Capasso, Melania; Gribben, John G

2015-07-09

T-cell defects, immune suppression, and poor antitumor immune responses are hallmarks of chronic lymphocytic leukemia (CLL), and PD-1/PD-L1 inhibitory signaling has emerged as a major immunosuppressive mechanism. However, the effect of different microenvironments and the confounding influence of aging are poorly understood. The current study uses the Eμ-TCL1 mouse model, which replicates human T-cell defects, as a preclinical platform to longitudinally examine patterns of T-cell dysfunction alongside developing CLL and in different microenvironments, with a focus on PD-1/PD-L1 interactions. The development of CLL was significantly associated with changes in T-cell phenotype across all organs and function. Although partly mirrored in aging wild-type mice, CLL-specific T-cell changes were identified. Murine CLL cells highly expressed PD-L1 and PD-L2 in all organs, with high PD-L1 expression in the spleen. CD3(+)CD8(+) T cells from leukemic and aging healthy mice highly expressed PD-1, identifying aging as a confounder, but adoptive transfer experiments demonstrated CLL-specific PD-1 induction. Direct comparisons of PD-1 expression and function between aging CLL mice and controls identified PD-1(+) T cells in CLL as a heterogeneous population with variable effector function. This is highly relevant for therapeutic targeting of CD8(+) T cells, showing the potential of reprogramming and selective subset expansion to restore antitumor immunity. © 2015 by The American Society of Hematology.

Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence

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Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels

2016-01-01

Background: The vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome are rare conditions. We aimed to present two cases with the vertebral defect, anal atresia, cardiac...... defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser co-occurrence from our local surgical center and through a systematic literature search detect published cases. Furthermore, we aimed to collect existing knowledge...... in the embryopathogenesis and genetics in order to discuss a possible link between the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome. Case presentation: Our first case was a white girl...

Birth Defects

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A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of ... in the United States is born with a birth defect. A birth defect may affect how the ...

Cardiac disease and arrhythmogenesis: Mechanistic insights from mouse models

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Lois Choy

2016-09-01

Full Text Available The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony. Last but not least, pharmacological models, despite being simplistic, have enabled us to understand the physiological mechanisms of arrhythmias and evaluate the anti-arrhythmic properties of experimental agents, such as gap junction modulators, that may be exert therapeutic effects in other cardiac diseases. In this article, we examine these in turn, demonstrating that primary inherited arrhythmic syndromes are now recognized to be more complex than abnormality in a particular ion channel, involving alterations in gene expression and structural remodelling. Conversely, in cardiomyopathies and heart failure, mutations in ion channels and proteins have been identified as underlying causes, and electrophysiological remodelling are recognized pathological features. Transgenic techniques causing mutagenesis in mice are extremely powerful in dissecting the relative contributions of different genes play in producing disease phenotypes. Mouse models can serve as useful systems in which to explore how protein defects contribute to arrhythmias and direct future therapy.

Impaired cholesterol esterification in primary brain cultures of the lysosomal cholesterol storage disorder (LCSD) mouse mutant

International Nuclear Information System (INIS)

Patel, S.C.; Suresh, S.; Weintroub, H.; Brady, R.O.; Pentchev, P.G.

1987-01-01

Esterification of cholesterol was investigated in primary neuroglial cultures obtained from newborn lysosomal cholesterol storage disorder (LCSD) mouse mutants. An impairment in 3 H-oleic acid incorporation into cholesteryl esters was demonstrated in cultures of homozygous LCSD brain. Primary cultures derived from other phenotypically normal pups of the carrier breeders esterified cholesterol at normal levels or at levels which were intermediary between normal and deficient indicating a phenotypic expression of the LCSD heterozygote genotype. These observations on LCSD mutant brain cells indicate that the defect in cholesterol esterification is closely related to the primary genetic defect and is expressed in neuroglial cells in culture

Composite PLA/PEG/nHA/Dexamethasone Scaffold Prepared by 3D Printing for Bone Regeneration.

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Li, Xiaoyuan; Wang, Yu; Wang, Zigui; Qi, Yanxin; Li, Linlong; Zhang, Peibiao; Chen, Xuesi; Huang, Yubin

2018-04-24

3D printing has become an essential part of bone tissue engineering and attracts great attention for the fabrication of bioactive scaffolds. Combining this rapid manufacturing technique with chemical precipitation, biodegradable 3D scaffold composed of polymer matrix (polylactic acid and polyethylene glycol), ceramics (nano hydroxyapatite), and drugs (dexamethasone (Dex)) is prepared. Results of water contact angle, differential scanning calorimeter, and mechanical tests confirm that incorporation of Dex leads to significantly improved wettability, higher crystallinity degree, and tunable degradation rates. In vitro experiment with mouse MC3T3-E1 cells implies that Dex released from scaffolds is not beneficial for early cell proliferation, but it improves late alkaline phosphatase secretion and mineralization significantly. Anti-inflammation assay of murine RAW 264.7 cells proves that Dex released from all the scaffolds successfully suppresses lipopolysaccharide induced interleukin-6 and inducible nitric oxide synthase secretion by M1 macrophages. Further in vivo experiment on rat calvarial defects indicates that scaffolds containing Dex promote osteoinduction and osteogenic response and would be promising candidates for clinical applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Frank-ter Haar syndrome associated with sagittal craniosynostosis and raised intracranial pressure.

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Bendon, Charlotte L; Fenwick, Aimée L; Hurst, Jane A; Nürnberg, Gudrun; Nürnberg, Peter; Wall, Steven A; Wilkie, Andrew O M; Johnson, David

2012-11-09

Frank-ter Haar syndrome is a rare disorder associated with skeletal, cardiac, ocular and craniofacial features including hypertelorism and brachycephaly. The most common underlying genetic defect in Frank-ter Haar syndrome appears to be a mutation in the SH3PXD2B gene on chromosome 5q35.1. Craniosynostosis, or premature fusion of the calvarial sutures, has not previously been described in Frank-ter Haar syndrome. We present a family of three affected siblings born to consanguineous parents with clinical features in keeping with a diagnosis of Frank-ter Haar syndrome. All three siblings have a novel mutation caused by the deletion of exon 13 of the SH3PXD2B gene. Two of the three siblings also have non-scaphocephalic sagittal synostosis associated with raised intracranial pressure. The clinical features of craniosynostosis and raised intracranial pressure in this family with a confirmed diagnosis of Frank-ter Haar syndrome expand the clinical spectrum of the disease. The abnormal cranial proportions in a mouse model of the disease suggests that the association is not coincidental. The possibility of craniosynostosis should be considered in individuals with a suspected diagnosis of Frank-ter Haar syndrome.

Correction of mouse ornithine transcarbamylase deficiency by gene transfer into the germ line

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Cavard, C; Grimber, G; Dubois, N; Chasse, J F; Bennoun, M; Minet-Thuriaux, M; Kamoun, P; Briand, P

1988-03-25

The sparse fur with abnormal skin and hair (Spf-ash) mouse is a model for the human x-linked hereditary disorder, ornithine transcarbamylase (OTC) deficiency. In Spf-ash mice, both OTC mRNA and enzyme activity are 5% of control values resulting in hyperammonemia, pronounced orotic aciduria and an abnormal phenotype characterized by growth retardation and sparse fur. Using microinjection, the authors introduced a construction containing rat OTC cDNA linked to the SV40 early promoter into fertilized eggs of Spf-ash mice. The expression of the transgene resulted in the development of a transgenic mouse whose phenotype and orotic acid excretion are fully normalized. Thus, the possibility of correcting hereditary enzymatic defect by gene transfer of heterologous cDNA coding for the normal enzyme has been demonstrated.

The morphogenesis of herpes simplex virus type 1 in infected parental mouse L fibroblasts and mutant gro29 cells

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Jensen, Helle Lone; Norrild, Bodil

2003-01-01

Mutants of cell lines and viruses are important biological tools. The pathway of herpesvirus particle maturation and egress are contentious issues. The mutant gro29 line of mouse L cells is defective for egress of herpes simplex virus type 1 (HSV-1) virions, and a candidate for studies of virus...

Detecting cardiac contractile activity in the early mouse embryo using multiple modalities

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Chiann-mun eChen

2015-01-01

Full Text Available The heart is one of the first organs to develop during mammalian embryogenesis. In the mouse, it starts to form shortly after gastrulation, and is derived primarily from embryonic mesoderm. The embryonic heart is unique in having to perform a mechanical contractile function while undergoing complex morphogenetic remodelling. Approaches to imaging the morphogenesis and contractile activity of the developing heart are important in understanding not only how this remodelling is controlled but also the origin of congenital heart defects. Here, we describe approaches for visualising contractile activity in the developing mouse embryo, using brightfield time lapse microscopy and confocal microscopy of calcium transients. We describe an algorithm for enhancing this image data and quantifying contractile activity from it. Finally we describe how atomic force microscopy can be used to record contractile activity prior to it being microscopically visible.

Rapamycin inhibits BMP-7-induced osteogenic and lipogenic marker expressions in fetal rat calvarial cells.

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Yeh, Lee-Chuan C; Ma, Xiuye; Ford, Jeffery J; Adamo, Martin L; Lee, John C

2013-08-01

Bone morphogenetic proteins (BMPs) promote osteoblast differentiation and bone formation in vitro and in vivo. BMPs canonically signal through Smad transcription factors, but BMPs may activate signaling pathways traditionally stimulated by growth factor tyrosine kinase receptors. Of these, the mTOR pathway has received considerable attention because BMPs activate P70S6K, a downstream effector of mTOR, suggesting that BMP-induced osteogenesis is mediated by mTOR activation. However, contradictory effects of the mTOR inhibitor rapamycin (RAPA) on bone formation have been reported. Since bone formation is thought to be inversely related to lipid accumulation and mTOR is also important for lipid synthesis, we postulated that BMP-7 may stimulate lipogenic enzyme expression in a RAPA-sensitive mechanism. To test this hypothesis, we determined the effects of RAPA on BMP-7-stimulated expression of osteogenic and lipogenic markers in cultured fetal rat calvarial cells. Our study showed that BMP-7 promoted the expression of osteogenic and lipogenic markers. The effect of BMP-7 on osteogenic markers was greater in magnitude than on lipogenic markers and was temporally more sustained. RAPA inhibited basal and BMP-7-stimulated osteogenic and lipogenic marker expression and bone nodule mineralization. The acetyl CoA carboxylase inhibitor TOFA stimulated the expression of osteoblast differentiation markers, whereas palmitate suppressed their expression. We speculate that the BMP-7-stimulated adipogenesis is part of the normal anabolic response to BMPs, but that inappropriate activation of the lipid biosynthetic pathway by mTOR could have deleterious effects on bone formation and could explain paradoxical effects of RAPA to promote bone formation. Copyright © 2013 Wiley Periodicals, Inc.

Inhibition of GSK3β rescues hippocampal development and learning in a mouse model of CDKL5 disorder.

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Fuchs, Claudia; Rimondini, Roberto; Viggiano, Rocchina; Trazzi, Stefania; De Franceschi, Marianna; Bartesaghi, Renata; Ciani, Elisabetta

2015-10-01

Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been identified in a rare neurodevelopmental disorder characterized by early-onset seizures, severe developmental delay, intellectual disability and Rett syndrome-like features. CDKL5 is highly expressed in the brain during early postnatal stages, suggesting its importance for brain maturation. Using a newly-generated Cdkl5 knockout (Cdkl5 -/Y) mouse, we recently found that loss of Cdkl5 impairs postnatal hippocampal development with a reduction in neuronal precursor survival and maturation. These defects were accompanied by increased activity of the glycogen synthase kinase 3β (GSK3β) a crucial inhibitory regulator of many neurodevelopmental processes. The goal of the current study was to establish whether inhibition of GSK3β corrects hippocampal developmental defects due to Cdkl5 loss. We found that treatment with the GSK3β inhibitor SB216763 restored neuronal precursor survival, dendritic maturation, connectivity and hippocampus-dependent learning and memory in the Cdkl5 -/Y mouse. Importantly, these effects were retained one month after treatment cessation. At present, there are no therapeutic strategies to improve the neurological defects of subjects with CDKL5 disorder. Current results point at GSK3β inhibitors as potential therapeutic tools for the improvement of abnormal brain development in CDKL5 disorder. Copyright © 2015. Published by Elsevier Inc.

Effect of Irradiation on Apoptosis, Cell Cycle Arrest and Calcified Nodule Formation of Rat Calvarial Osteoblast

International Nuclear Information System (INIS)

Lee, Young Mi; Choi, Hang Moon; Heo, Min Suk; Lee, Sam Sun; Choi, Soon Chul; Park, Tae Won

2000-01-01

The study was aimed to detect the induction of apoptosis, cell cycle arrest and calcified nodule formation after irradiation on primarily cultured osteoblasts. Using rat calvarial osteoblasts, the effects of irradiation on apoptosis, cell cycle arrest, and calcified nodule formation were studied. The single irradiation of 10, 20 Gy was done with 5.38 Gy/min dose rate using the 137 Cs cell irradiator at 4th and 14th day of culture. Apoptosis induction and cell cycle arrest were assayed by the flow cytometry at 1, 2, 3, and 4 days after irradiation. The formation of calcified nodules was observed by alizarin red staining at 1, 3, 10, 14 days after irradiation at 4th day of culture, and at 1, 4, 5 days after irradiation at 14th day of culture. Apoptosis was not induced by 10 or 20 Gy independent of irradiation and culture period. Irradiation did not induced G1 arrest in post-irradiated osteoblasts. After irradiation at 4th-day of culture, G2 arrest was induced but it was not statistically significant after irradiation at 14th-day of culture. In the case of irradiated cells at 4th day of culture, calcified nodules were not formed and at 14th-day of culture after irradiation, calcified nodule formation did not affected. Taken together, these results suggest that irradiation at the dose of 10-20 Gy would not affect apoptosis induction of osteoblasts. Cell cycle and calcified nodule formation were influenced by the level of differentiation of osteblasts.

SIRT1, 2, 3 protect mouse oocytes from postovulatory aging.

Science.gov (United States)

Zhang, Teng; Zhou, Yang; Li, Li; Wang, Hong-Hui; Ma, Xue-Shan; Qian, Wei-Ping; Shen, Wei; Schatten, Heide; Sun, Qing-Yuan

2016-04-01

The quality of metaphase II oocytes will undergo a time-dependent deterioration following ovulation as the result of the oocyte aging process. In this study, we determined that the expression of sirtuin family members (SIRT1, 2, 3) was dramatically reduced in mouse oocytes aged in vivo or in vitro. Increased intracellular ROS was observed when SIRT1, 2, 3 activity was inhibited. Increased frequency of spindle defects and disturbed distribution of mitochondria were also observed in MII oocytes aged in vitro after treatment with Nicotinamide (NAM), indicating that inhibition of SIRT1, 2, 3 may accelerate postovulatory oocyte aging. Interestingly, when MII oocytes were exposed to caffeine, the decline of SIRT1, 2, 3 mRNA levels was delayed and the aging-associated defective phenotypes could be improved. The results suggest that the SIRT1, 2, 3 pathway may play a potential protective role against postovulatory oocyte aging by controlling ROS generation.

Requirement of mouse BCCIP for neural development and progenitor proliferation.

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Yi-Yuan Huang

Full Text Available Multiple DNA repair pathways are involved in the orderly development of neural systems at distinct stages. The homologous recombination (HR pathway is required to resolve stalled replication forks and critical for the proliferation of progenitor cells during neural development. BCCIP is a BRCA2 and CDKN1A interacting protein implicated in HR and inhibition of DNA replication stress. In this study, we determined the role of BCCIP in neural development using a conditional BCCIP knock-down mouse model. BCCIP deficiency impaired embryonic and postnatal neural development, causing severe ataxia, cerebral and cerebellar defects, and microcephaly. These development defects are associated with spontaneous DNA damage and subsequent cell death in the proliferative cell populations of the neural system during embryogenesis. With in vitro neural spheroid cultures, BCCIP deficiency impaired neural progenitor's self-renewal capability, and spontaneously activated p53. These data suggest that BCCIP and its anti-replication stress functions are essential for normal neural development by maintaining an orderly proliferation of neural progenitors.

No amelioration of uromodulin maturation and trafficking defect by sodium 4-phenylbutyrate in vivo: studies in mouse models of uromodulin-associated kidney disease.

Science.gov (United States)

Kemter, Elisabeth; Sklenak, Stefanie; Rathkolb, Birgit; Hrabě de Angelis, Martin; Wolf, Eckhard; Aigner, Bernhard; Wanke, Ruediger

2014-04-11

Uromodulin (UMOD)-associated kidney disease (UAKD) belongs to the hereditary progressive ER storage diseases caused by maturation defects of mutant UMOD protein. Current treatments of UAKD patients are symptomatic and cannot prevent disease progression. Two in vitro studies reported a positive effect of the chemical chaperone sodium 4-phenylbutyrate (4-PBA) on mutant UMOD maturation. Thus, 4-PBA was suggested as a potential treatment for UAKD. This study evaluated the effects of 4-PBA in two mouse models of UAKD. In contrast to previous in vitro studies, treatment with 4-PBA did not increase HSP70 expression or improve maturation and trafficking of mutant UMOD in vivo. Kidney function of UAKD mice was actually deteriorated by 4-PBA treatment. In transfected tubular epithelial cells, 4-PBA did not improve maturation but increased the expression level of both mutant and wild-type UMOD protein. Activation of NF-κB pathway in thick ascending limb of Henle's loop cells of UAKD mice was detected by increased abundance of RelB and phospho-IκB kinase α/β, an indirect activator of NF-κB. Furthermore, the abundance of NF-κB1 p105/p50, NF-κB2 p100/p52, and TRAF2 was increased in UAKD. NF-κB activation was identified as a novel disease mechanism of UAKD and might be a target for therapeutic intervention.

Rag defects and thymic stroma: lessons from animal models

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Veronica eMarrella

2014-06-01

Full Text Available Thymocytes and thymic epithelial cells (TECs cross-talk is essential to support T-cell development and preserve thymic architecture and maturation of TECs and Foxp3+ natural regulatory T (nTreg cells. Accordingly, disruption of thymic lymphostromal cross-talk may have major implications on the thymic mechanisms that govern T cell tolerance. Several genetic defects have been described in humans that affect early stages of T cell development (leading to Severe Combined Immune Deficiency, SCID or late stages in thymocyte maturation (resulting in combined immunodeficiency. Hypomorphic mutations in SCID-causing genes may allow for generation of a limited pool of T lymphocytes with a restricted repertoire. These conditions are often associated with infiltration of peripheral tissues by activated T cells and immune dysregulation, as best exemplified by Omenn syndrome (OS. In this review, we will discuss our recent findings on abnormalities of thymic microenvironment in OS with a special focus of defective maturation of TECs, altered distribution of thymic dendritic cells (DCs and impairment of deletional and non-deletional mechanisms of central tolerance. Here, taking advantage of mouse models of OS and atypical SCID, we will discuss how modifications in stromal compartment impact and shape lymphocyte differentiation, and vice versa how inefficient T cell signalling results in defective stromal maturation. These findings are instrumental to understand the extent to which novel therapeutic strategies should act on thymic stroma to achieve full immune reconstitution.

Generation of a mouse model for studying the role of upregulated RTEL1 activity in tumorigenesis.

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Wu, Xiaoli; Sandhu, Sumit; Nabi, Zinnatun; Ding, Hao

2012-10-01

Regulator of telomere length 1 (RTEL1) is a DNA helicase protein that has been demonstrated to be required for the maintenance of telomere length and genomic stability. It has also been found to be essential for DNA homologous recombination during DNA repairing. Human RTEL1 genomic locus (20q13.3) is frequently amplified in multiple types of human cancers, including hepatocellular carcinoma and gastrointestinal tract tumors, indicating that upregulated RTEL1 activity could be important for tumorigenesis. In this study, we have developed a conditional transgenic mouse model that overexpress mouse Rtel1 in a Cre-excision manner. By crossing with a ubiquitous Cre mouse line, we further demonstrated that these established Rtel1 conditional transgenic mice allow to efficiently and highly express a functional Rtel1 that is able to rescue the embryonic defects of Rtel1 null mouse allele. Furthermore, we demonstrated that more than 70% transgenic mice that widely overexpress Rtel1 developed liver tumors that recapitulate many malignant features of human hepatocellular carcinoma (HCC). Our work not only generated a valuable mouse model for determining the role of RTEL1 in the development of cancers, but also provided the first genetic evidence to support that amplification of RTEL1, as observed in several types of human cancers, is tumorigenic.

Novel insights on the relationship between T-tubular defects and contractile dysfunction in a mouse model of hypertrophic cardiomyopathy.

Science.gov (United States)

Crocini, C; Ferrantini, C; Scardigli, M; Coppini, R; Mazzoni, L; Lazzeri, E; Pioner, J M; Scellini, B; Guo, A; Song, L S; Yan, P; Loew, L M; Tardiff, J; Tesi, C; Vanzi, F; Cerbai, E; Pavone, F S; Sacconi, L; Poggesi, C

2016-02-01

Abnormalities of cardiomyocyte Ca(2+) homeostasis and excitation-contraction (E-C) coupling are early events in the pathogenesis of hypertrophic cardiomyopathy (HCM) and concomitant determinants of the diastolic dysfunction and arrhythmias typical of the disease. T-tubule remodelling has been reported to occur in HCM but little is known about its role in the E-C coupling alterations of HCM. Here, the role of T-tubule remodelling in the electro-mechanical dysfunction associated to HCM is investigated in the Δ160E cTnT mouse model that expresses a clinically-relevant HCM mutation. Contractile function of intact ventricular trabeculae is assessed in Δ160E mice and wild-type siblings. As compared with wild-type, Δ160E trabeculae show prolonged kinetics of force development and relaxation, blunted force-frequency response with reduced active tension at high stimulation frequency, and increased occurrence of spontaneous contractions. Consistently, prolonged Ca(2+) transient in terms of rise and duration are also observed in Δ160E trabeculae and isolated cardiomyocytes. Confocal imaging in cells isolated from Δ160E mice reveals significant, though modest, remodelling of T-tubular architecture. A two-photon random access microscope is employed to dissect the spatio-temporal relationship between T-tubular electrical activity and local Ca(2+) release in isolated cardiomyocytes. In Δ160E cardiomyocytes, a significant number of T-tubules (>20%) fails to propagate action potentials, with consequent delay of local Ca(2+) release. At variance with wild-type, we also observe significantly increased variability of local Ca(2+) transient rise as well as higher Ca(2+)-spark frequency. Although T-tubule structural remodelling in Δ160E myocytes is modest, T-tubule functional defects determine non-homogeneous Ca(2+) release and delayed myofilament activation that significantly contribute to mechanical dysfunction. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All

Loss of Apela Peptide in Mice Causes Low Penetrance Embryonic Lethality and Defects in Early Mesodermal Derivatives

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Laina Freyer

2017-08-01

Full Text Available Apela (also known as Elabela, Ende, and Toddler is a small signaling peptide that activates the G-protein-coupled receptor Aplnr to stimulate cell migration during zebrafish gastrulation. Here, using CRISPR/Cas9 to generate a null, reporter-expressing allele, we study the role of Apela in the developing mouse embryo. We found that loss of Apela results in low-penetrance cardiovascular defects that manifest after the onset of circulation. Three-dimensional micro-computed tomography revealed a higher penetrance of vascular remodeling defects, from which some mutants recover, and identified extraembryonic anomalies as the earliest morphological distinction in Apela mutant embryos. Transcriptomics at late gastrulation identified aberrant upregulation of erythroid and myeloid markers in mutant embryos prior to the appearance of physical malformations. Double-mutant analyses showed that loss of Apela signaling impacts early Aplnr-expressing mesodermal populations independently of the alternative ligand Apelin, leading to lethal cardiac defects in some Apela null embryos.

Cell-autonomous progeroid changes in conditional mouse models for repair endonuclease XPG deficiency.

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Sander Barnhoorn

2014-10-01

Full Text Available As part of the Nucleotide Excision Repair (NER process, the endonuclease XPG is involved in repair of helix-distorting DNA lesions, but the protein has also been implicated in several other DNA repair systems, complicating genotype-phenotype relationship in XPG patients. Defects in XPG can cause either the cancer-prone condition xeroderma pigmentosum (XP alone, or XP combined with the severe neurodevelopmental disorder Cockayne Syndrome (CS, or the infantile lethal cerebro-oculo-facio-skeletal (COFS syndrome, characterized by dramatic growth failure, progressive neurodevelopmental abnormalities and greatly reduced life expectancy. Here, we present a novel (conditional Xpg-/- mouse model which -in a C57BL6/FVB F1 hybrid genetic background- displays many progeroid features, including cessation of growth, loss of subcutaneous fat, kyphosis, osteoporosis, retinal photoreceptor loss, liver aging, extensive neurodegeneration, and a short lifespan of 4-5 months. We show that deletion of XPG specifically in the liver reproduces the progeroid features in the liver, yet abolishes the effect on growth or lifespan. In addition, specific XPG deletion in neurons and glia of the forebrain creates a progressive neurodegenerative phenotype that shows many characteristics of human XPG deficiency. Our findings therefore exclude that both the liver as well as the neurological phenotype are a secondary consequence of derailment in other cell types, organs or tissues (e.g. vascular abnormalities and support a cell-autonomous origin caused by the DNA repair defect itself. In addition they allow the dissection of the complex aging process in tissue- and cell-type-specific components. Moreover, our data highlight the critical importance of genetic background in mouse aging studies, establish the Xpg-/- mouse as a valid model for the severe form of human XPG patients and segmental accelerated aging, and strengthen the link between DNA damage and aging.

Epigenetic functions enriched in transcription factors binding to mouse recombination hotspots.

Science.gov (United States)

Wu, Min; Kwoh, Chee-Keong; Przytycka, Teresa M; Li, Jing; Zheng, Jie

2012-06-21

The regulatory mechanism of recombination is a fundamental problem in genomics, with wide applications in genome-wide association studies, birth-defect diseases, molecular evolution, cancer research, etc. In mammalian genomes, recombination events cluster into short genomic regions called "recombination hotspots". Recently, a 13-mer motif enriched in hotspots is identified as a candidate cis-regulatory element of human recombination hotspots; moreover, a zinc finger protein, PRDM9, binds to this motif and is associated with variation of recombination phenotype in human and mouse genomes, thus is a trans-acting regulator of recombination hotspots. However, this pair of cis and trans-regulators covers only a fraction of hotspots, thus other regulators of recombination hotspots remain to be discovered. In this paper, we propose an approach to predicting additional trans-regulators from DNA-binding proteins by comparing their enrichment of binding sites in hotspots. Applying this approach on newly mapped mouse hotspots genome-wide, we confirmed that PRDM9 is a major trans-regulator of hotspots. In addition, a list of top candidate trans-regulators of mouse hotspots is reported. Using GO analysis we observed that the top genes are enriched with function of histone modification, highlighting the epigenetic regulatory mechanisms of recombination hotspots.

Immobile defects in ferroelastic walls: Wall nucleation at defect sites

Science.gov (United States)

He, X.; Salje, E. K. H.; Ding, X.; Sun, J.

2018-02-01

Randomly distributed, static defects are enriched in ferroelastic domain walls. The relative concentration of defects in walls, Nd, follows a power law distribution as a function of the total defect concentration C: N d ˜ C α with α = 0.4 . The enrichment Nd/C ranges from ˜50 times when C = 10 ppm to ˜3 times when C = 1000 ppm. The resulting enrichment is due to nucleation at defect sites as observed in large scale MD simulations. The dynamics of domain nucleation and switching is dependent on the defect concentration. Their energy distribution follows the power law with exponents during yield between ɛ ˜ 1.82 and 2.0 when the defect concentration increases. The power law exponent is ɛ ≈ 2.7 in the plastic regime, independent of the defect concentration.

Lipopolysaccharides with acylation defects potentiate TLR4 signaling and shape T cell responses.

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Anna Martirosyan

Full Text Available Lipopolysaccharides or endotoxins are components of Gram-negative enterobacteria that cause septic shock in mammals. However, a LPS carrying hexa-acyl lipid A moieties is highly endotoxic compared to a tetra-acyl LPS and the latter has been considered as an antagonist of hexa-acyl LPS-mediated TLR4 signaling. We investigated the relationship between the structure and the function of bacterial LPS in the context of human and mouse dendritic cell activation. Strikingly, LPS with acylation defects were capable of triggering a strong and early TLR4-dependent DC activation, which in turn led to the activation of the proteasome machinery dampening the pro-inflammatory cytokine secretion. Upon activation with tetra-acyl LPS both mouse and human dendritic cells triggered CD4(+ T and CD8(+ T cell responses and, importantly, human myeloid dendritic cells favored the induction of regulatory T cells. Altogether, our data suggest that LPS acylation controlled by pathogenic bacteria might be an important strategy to subvert adaptive immunity.

Nucleotide excision repair- and p53-deficient mouse models in cancer research

Energy Technology Data Exchange (ETDEWEB)

Hoogervorst, Esther M. [Laboratory of Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven (Netherlands); Utrecht University, Department of Pathobiology, Utrecht (Netherlands); Steeg, Harry van [Laboratory of Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven (Netherlands); Vries, Annemieke de [Laboratory of Toxicology, Pathology and Genetics, National Institute of Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven (Netherlands)]. E-mail: Annemieke.de.Vries@rivm.nl

2005-07-01

Cancer is caused by the loss of controlled cell growth due to mutational (in)activation of critical genes known to be involved in cell cycle regulation. Three main mechanisms are known to be involved in the prevention of cells from becoming cancerous; DNA repair and cell cycle control, important to remove DNA damage before it will be fixed into mutations and apoptosis, resulting in the elimination of cells containing severe DNA damage. Several human syndromes are known to have (partially) deficiencies in these pathways, and are therefore highly cancer prone. Examples are xeroderma pigmentosum (XP) caused by an inborn defect in the nucleotide excision repair (NER) pathway and the Li-Fraumeni syndrome, which is the result of a germ line mutation in the p53 gene. XP patients develop skin cancer on sun exposed areas at a relatively early age, whereas Li-Fraumeni patients spontaneously develop a wide variety of early onset tumors, including sarcomas, leukemia's and mammary gland carcinomas. Several mouse models have been generated to mimic these human syndromes, providing us information about the role of these particular gene defects in the tumorigenesis process. In this review, spontaneous phenotypes of mice deficient for nucleotide excision repair and/or the p53 gene will be described, together with their responses upon exposure to either chemical carcinogens or radiation. Furthermore, possible applications of these and newly generated mouse models for cancer will be given.

Left cardiac isomerism in the Sonic hedgehog null mouse.

Science.gov (United States)

Hildreth, Victoria; Webb, Sandra; Chaudhry, Bill; Peat, Jonathan D; Phillips, Helen M; Brown, Nigel; Anderson, Robert H; Henderson, Deborah J

2009-06-01

Sonic hedgehog (Shh) is a secreted morphogen necessary for the production of sidedness in the developing embryo. In this study, we describe the morphology of the atrial chambers and atrioventricular junctions of the Shh null mouse heart. We demonstrate that the essential phenotypic feature is isomerism of the left atrial appendages, in combination with an atrioventricular septal defect and a common atrioventricular junction. These malformations are known to be frequent in humans with left isomerism. To confirm the presence of left isomerism, we show that Pitx2c, a recognized determinant of morphological leftness, is expressed in the Shh null mutants on both the right and left sides of the inflow region, and on both sides of the solitary arterial trunk exiting from the heart. It has been established that derivatives of the second heart field expressing Isl1 are asymmetrically distributed in the developing normal heart. We now show that this population is reduced in the hearts from the Shh null mutants, likely contributing to the defects. To distinguish the consequences of reduced contributions from the second heart field from those of left-right patterning disturbance, we disrupted the movement of second heart field cells into the heart by expressing dominant-negative Rho kinase in the population of cells expressing Isl1. This resulted in absence of the vestibular spine, and presence of atrioventricular septal defects closely resembling those seen in the hearts from the Shh null mutants. The primary atrial septum, however, was well formed, and there was no evidence of isomerism of the atrial appendages, suggesting that these features do not relate to disruption of the contributions made by the second heart field. We demonstrate, therefore, that the Shh null mouse is a model of isomerism of the left atrial appendages, and show that the recognized associated malformations found at the venous pole of the heart in the setting of left isomerism are likely to arise from

Staphylococcus aureus Colonization of the Mouse Gastrointestinal Tract Is Modulated by Wall Teichoic Acid, Capsule, and Surface Proteins.

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Yoshiki Misawa

2015-07-01

Full Text Available Staphylococcus aureus colonizes the nose, throat, skin, and gastrointestinal (GI tract of humans. GI carriage of S. aureus is difficult to eradicate and has been shown to facilitate the transmission of the bacterium among individuals. Although staphylococcal colonization of the GI tract is asymptomatic, it increases the likelihood of infection, particularly skin and soft tissue infections caused by USA300 isolates. We established a mouse model of persistent S. aureus GI colonization and characterized the impact of selected surface antigens on colonization. In competition experiments, an acapsular mutant colonized better than the parental strain Newman, whereas mutants defective in sortase A and clumping factor A showed impaired ability to colonize the GI tract. Mutants lacking protein A, clumping factor B, poly-N-acetyl glucosamine, or SdrCDE showed no defect in colonization. An S. aureus wall teichoic acid (WTA mutant (ΔtagO failed to colonize the mouse nose or GI tract, and the tagO and clfA mutants showed reduced adherence in vitro to intestinal epithelial cells. The tagO mutant was recovered in lower numbers than the wild type strain in the murine stomach and duodenum 1 h after inoculation. This reduced fitness correlated with the in vitro susceptibility of the tagO mutant to bile salts, proteases, and a gut-associated defensin. Newman ΔtagO showed enhanced susceptibility to autolysis, and an autolysin (atl tagO double mutant abrogated this phenotype. However, the atl tagO mutant did not survive better in the mouse GI tract than the tagO mutant. Our results indicate that the failure of the tagO mutant to colonize the GI tract correlates with its poor adherence and susceptibility to bactericidal factors within the mouse gut, but not to enhanced activity of its major autolysin.

Studies of defects and defect agglomerates by positron annihilation spectroscopy

DEFF Research Database (Denmark)

Eldrup, Morten Mostgaard; Singh, B.N.

1997-01-01

A brief introduction to positron annihilation spectroscopy (PAS), and in particular lo its use for defect studies in metals is given. Positrons injected into a metal may become trapped in defects such as vacancies, vacancy clusters, voids, bubbles and dislocations and subsequently annihilate from...... the trapped state iri the defect. The annihilation characteristics (e.g., the lifetime of the positron) can be measured and provide information about the nature of the defect (e.g., size, density, morphology). The technique is sensitive to both defect size (in the range from monovacancies up to cavities...

Defect modelling

International Nuclear Information System (INIS)

Norgett, M.J.

1980-01-01

Calculations, drawing principally on developments at AERE Harwell, of the relaxation about lattice defects are reviewed with emphasis on the techniques required for such calculations. The principles of defect modelling are outlined and various programs developed for defect simulations are discussed. Particular calculations for metals, ionic crystals and oxides, are considered. (UK)

Patterning and gastrulation defects caused by the tw18 lethal are due to loss of Ppp2r1a

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Lisette Lange

2017-06-01

Full Text Available The mouse t haplotype, a variant 20 cM genomic region on Chromosome 17, harbors 16 embryonic control genes identified by recessive lethal mutations isolated from wild mouse populations. Due to technical constraints so far only one of these, the tw5 lethal, has been cloned and molecularly characterized. Here we report the molecular isolation of the tw18 lethal. Embryos carrying the tw18 lethal die from major gastrulation defects commencing with primitive streak formation at E6.5. We have used transcriptome and marker gene analyses to describe the molecular etiology of the tw18 phenotype. We show that both WNT and Nodal signal transduction are impaired in the mutant epiblast, causing embryonic patterning defects and failure of primitive streak and mesoderm formation. By using a candidate gene approach, gene knockout by homologous recombination and genetic rescue, we have identified the gene causing the tw18 phenotype as Ppp2r1a, encoding the PP2A scaffolding subunit PR65alpha. Our work highlights the importance of phosphatase 2A in embryonic patterning, primitive streak formation, gastrulation, and mesoderm formation downstream of WNT and Nodal signaling.

Centralized mouse repositories.

Science.gov (United States)

Donahue, Leah Rae; Hrabe de Angelis, Martin; Hagn, Michael; Franklin, Craig; Lloyd, K C Kent; Magnuson, Terry; McKerlie, Colin; Nakagata, Naomi; Obata, Yuichi; Read, Stuart; Wurst, Wolfgang; Hörlein, Andreas; Davisson, Muriel T

2012-10-01

Because the mouse is used so widely for biomedical research and the number of mouse models being generated is increasing rapidly, centralized repositories are essential if the valuable mouse strains and models that have been developed are to be securely preserved and fully exploited. Ensuring the ongoing availability of these mouse strains preserves the investment made in creating and characterizing them and creates a global resource of enormous value. The establishment of centralized mouse repositories around the world for distributing and archiving these resources has provided critical access to and preservation of these strains. This article describes the common and specialized activities provided by major mouse repositories around the world.

Cerebellar defects in a mouse model of juvenile neuronal ceroid lipofuscinosis.

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Weimer, Jill M; Benedict, Jared W; Getty, Amanda L; Pontikis, Charlie C; Lim, Ming J; Cooper, Jonathan D; Pearce, David A

2009-04-17

Juvenile neuronal ceroid lipofuscinosis (JNCL), or Batten disease, is a neurodegenerative disease resulting from a mutation in CLN3, which presents clinically with visual deterioration, seizures, motor impairments, cognitive decline, hallucinations, loss of circadian rhythm, and premature death in the late-twenties to early-thirties. Using a Cln3 null (Cln3(-/-)) mouse, we report here several deficits in the cerebellum in the absence of Cln3, including cell loss and early onset motor deficits. Surprisingly, early onset glial activation and selective neuronal loss within the mature fastigial pathway of the deep cerebellar nuclei (DCN), a region critical for balance and coordination, are seen in many regions of the Cln3(-/-) cerebellum. Additionally, there is a loss of Purkinje cells (PC) in regions of robust Bergmann glia activation in Cln3(-/-) mice and human JNCL post-mortem cerebellum. Moreover, the Cln3(-/-) cerebellum had a mis-regulation in granule cell proliferation and maintenance of PC dendritic arborization and spine density. Overall, this study defines a novel multi-faceted, early-onset cerebellar disruption in the Cln3 null brain, including glial activation, cell loss, and aberrant cell proliferation and differentiation. These early alterations in the maturation of the cerebellum could underlie some of the motor deficits and pathological changes seen in JNCL patients.

Arsenate-induced maternal glucose intolerance and neural tube defects in a mouse model

International Nuclear Information System (INIS)

Hill, Denise S.; Wlodarczyk, Bogdan J.; Mitchell, Laura E.; Finnell, Richard H.

2009-01-01

Background: Epidemiological studies have linked environmental arsenic (As) exposure to increased type 2 diabetes risk. Periconceptional hyperglycemia is a significant risk factor for neural tube defects (NTDs), the second most common structural birth defect. A suspected teratogen, arsenic (As) induces NTDs in laboratory animals. Objectives: We investigated whether maternal glucose homeostasis disruption was responsible for arsenate-induced NTDs in a well-established dosing regimen used in studies of arsenic's teratogenicity in early neurodevelopment. Methods: We evaluated maternal intraperitoneal (IP) exposure to As 9.6 mg/kg (as sodium arsenate) in LM/Bc/Fnn mice for teratogenicity and disruption of maternal plasma glucose and insulin levels. Selected compounds (insulin pellet, sodium selenate (SS), N-acetyl cysteine (NAC), L-methionine (L-Met), N-tert-Butyl-α-phenylnitrone (PBN)) were investigated for their potential to mitigate arsenate's effects. Results: Arsenate caused significant glucose elevation during an IP glucose tolerance test (IPGTT). Insulin levels were not different between arsenate and control dams before (arsenate, 0.55 ng/dl; control, 0.48 ng/dl) or after glucose challenge (arsenate, 1.09 ng/dl; control, 0.81 ng/dl). HOMA-IR index was higher for arsenate (3.9) vs control (2.5) dams (p = 0.0260). Arsenate caused NTDs (100%, p < 0.0001). Insulin pellet and NAC were the most successful rescue agents, reducing NTD rates to 45% and 35%. Conclusions: IPGTT, insulin assay, and HOMA-IR results suggest a modest failure of glucose stimulated insulin secretion and insulin resistance characteristic of glucose intolerance. Insulin's success in preventing arsenate-induced NTDs provides evidence that these arsenate-induced NTDs are secondary to elevated maternal glucose. The NAC rescue, which did not restore maternal glucose or insulin levels, suggests oxidative disruption plays a role.

Effects of calcium phosphate/chitosan composite on bone healing in rats: calcium phosphate induces osteon formation.

Science.gov (United States)

Fernández, Tulio; Olave, Gilberto; Valencia, Carlos H; Arce, Sandra; Quinn, Julian M W; Thouas, George A; Chen, Qi-Zhi

2014-07-01

Vascularization of an artificial graft represents one of the most significant challenges facing the field of bone tissue engineering. Over the past decade, strategies to vascularize artificial scaffolds have been intensively evaluated using osteoinductive calcium phosphate (CaP) biomaterials in animal models. In this work, we observed that CaP-based biomaterials implanted into rat calvarial defects showed remarkably accelerated formation and mineralization of new woven bone in defects in the initial stages, at a rate of ∼60 μm/day (0.8 mg/day), which was considerably higher than normal bone growth rates (several μm/day, 0.1 mg/day) in implant-free controls of the same age. Surprisingly, we also observed histological evidence of primary osteon formation, indicated by blood vessels in early-region fibrous tissue, which was encapsulated by lamellar osteocyte structures. These were later fully replaced by compact bone, indicating complete regeneration of calvarial bone. Thus, the CaP biomaterial used here is not only osteoinductive, but vasculogenic, and it may have contributed to the bone regeneration, despite an absence of osteons in normal rat calvaria. Further investigation will involve how this strategy can regulate formation of vascularized cortical bone such as by control of degradation rate, and use of models of long, dense bones, to more closely approximate repair of human cortical bone.

Immobilization of Murine Anti-BMP-2 Monoclonal Antibody on Various Biomaterials for Bone Tissue Engineering

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Sahar Ansari

2014-01-01

Full Text Available Biomaterials are widely used as scaffolds for tissue engineering. We have developed a strategy for bone tissue engineering that entails application of immobilized anti-BMP-2 monoclonal antibodies (mAbs to capture endogenous BMPs in vivo and promote antibody-mediated osseous regeneration (AMOR. The purpose of the current study was to compare the efficacy of immobilization of a specific murine anti-BMP-2 mAb on three different types of biomaterials and to evaluate their suitability as scaffolds for AMOR. Anti-BMP-2 mAb or isotype control mAb was immobilized on titanium (Ti microbeads, alginate hydrogel, and ACS. The treated biomaterials were surgically implanted in rat critical-sized calvarial defects. After 8 weeks, de novo bone formation was assessed using micro-CT and histomorphometric analyses. Results showed de novo bone regeneration with all three scaffolds with immobilized anti-BMP-2 mAb, but not isotype control mAb. Ti microbeads showed the highest volume of bone regeneration, followed by ACS. Alginate showed the lowest volume of bone. Localization of BMP-2, -4, and -7 antigens was detected on all 3 scaffolds with immobilized anti-BMP-2 mAb implanted in calvarial defects. Altogether, these data suggested a potential mechanism for bone regeneration through entrapment of endogenous BMP-2, -4, and -7 proteins leading to bone formation using different types of scaffolds via AMOR.

Structure and inhibition analysis of the mouse SAD-B C-terminal fragment.

Science.gov (United States)

Ma, Hui; Wu, Jing-Xiang; Wang, Jue; Wang, Zhi-Xin; Wu, Jia-Wei

2016-10-01

The SAD (synapses of amphids defective) kinases, including SAD-A and SAD-B, play important roles in the regulation of neuronal development, cell cycle, and energy metabolism. Our recent study of mouse SAD-A identified a unique autoinhibitory sequence (AIS), which binds at the junction of the kinase domain (KD) and the ubiquitin-associated (UBA) domain and exerts autoregulation in cooperation with UBA. Here, we report the crystal structure of the mouse SAD-B C-terminal fragment including the AIS and the kinase-associated domain 1 (KA1) at 2.8 Å resolution. The KA1 domain is structurally conserved, while the isolated AIS sequence is highly flexible and solvent-accessible. Our biochemical studies indicated that the SAD-B AIS exerts the same autoinhibitory role as that in SAD-A. We believe that the flexible isolated AIS sequence is readily available for interaction with KD-UBA and thus inhibits SAD-B activity.

Defects in Stratum Corneum Desquamation Are the Predominant Effect of Impaired ABCA12 Function in a Novel Mouse Model of Harlequin Ichthyosis.

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Lei Zhang

Full Text Available Harlequin Ichthyosis is a severe skin disease caused by mutations in the human gene encoding ABCA12. Here, we characterize a novel mutation in intron 29 of the mouse Abca12 gene that leads to the loss of a 5' splice donor site and truncation of the Abca12 RNA transcript. Homozygous mutants of this smooth skin or smsk allele die perinatally with shiny translucent skin, typical of animal models of Harlequin Ichthyosis. Characterization of smsk mutant skin showed that the delivery of glucosylceramides and CORNEODESMOSIN was defective, while ultrastructural analysis revealed abnormal lamellar bodies and the absence of lipid lamellae in smsk epidermis. Unexpectedly, mutant stratum corneum remained intact when subjected to harsh chemical dissociation procedures. Moreover, both KALLIKREIN 5 and -7 were drastically decreased, with retention of desmoplakin in mutant SC. In cultured wild type keratinocytes, both KALLIKREIN 5 and -7 colocalized with ceramide metabolites following calcium-induced differentiation. Reducing the intracellular levels of glucosylceramide with a glucosylceramide synthase inhibitor resulted in decreased secretion of KALLIKREIN proteases by wild type keratinocytes, but not by smsk mutant keratinocytes. Together, these findings suggest an essential role for ABCA12 in transferring not only lipids, which are required for the formation of multilamellar structures in the stratum corneum, but also proteolytic enzymes that are required for normal desquamation. Smsk mutant mice recapitulate many of the pathological features of HI and can be used to explore novel topical therapies against a potentially lethal and debilitating neonatal disease.

Human Usher 1B/mouse shaker-1: the retinal phenotype discrepancy explained by the presence/absence of myosin VIIA in the photoreceptor cells.

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el-Amraoui, A; Sahly, I; Picaud, S; Sahel, J; Abitbol, M; Petit, C

1996-08-01

Usher syndrome type 1 (USH1) associates severe congenital deafness, vestibular dysfunction and progressive retinitis pigmentosa leading to blindness. The gene encoding myosin VIIA is responsible for USH1B. Mutations in the murine orthologous gene lead to the shaker-1 phenotype, which manifests cochlear and vestibular dysfunction, without any retinal defect. To address this phenotypic discrepancy, the expression of myosin VIIA in retinal cells was analyzed in human and mouse during embryonic development and adult life. In the human embryo, myosin VIIA was present first in the pigment epithelium cells, and later in these cells as well as in the photoreceptor cells. In the adult human retina, myosin VIIA was present in both cell types. In contrast, in mouse, only pigment epithelium cells expressed the protein throughout development and adult life. Myosin VIIA was also found to be absent in the photoreceptor cells of other rodents (rat and guinea-pig), whereas these cells expressed the protein in amphibians, avians and primates. These observations suggest that retinitis pigmentosa of USH1B results from a primary rod and cone defect. The USH1B/shaker-1 paradigm illustrates a species-specific cell pattern of gene expression as a possible cause for the discrepancy between phenotypes involving defective orthologous genes in man and mouse. Interestingly, in the photoreceptor cells, myosin VIIA is mainly localized in the inner and base of outer segments as well as in the synaptic ending region where it is co-localized with the synaptic vesicles. Therefore, we suggest that myosin VIIA might play a role in the trafficking of ribbon-synaptic vesicle complexes and the renewal processes of the outer photoreceptor disks.

Dmdmdx/Largemyd: a new mouse model of neuromuscular diseases useful for studying physiopathological mechanisms and testing therapies

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Poliana C. M. Martins

2013-09-01

Although muscular dystrophies are among the most common human genetic disorders, there are few treatment options available. Animal models have become increasingly important for testing new therapies prior to entering human clinical trials. The Dmdmdx mouse is the most widely used animal model for Duchenne muscular dystrophy (DMD, presenting the same molecular and protein defect as seen in humans with the disease. However, this mouse is not useful for clinical trials because of its very mild phenotype. The mouse model for congenital myodystrophy type 1D, Largemyd, harbors a mutation in the glycosyltransferase Large gene and displays a severe phenotype. To help elucidate the role of the proteins dystrophin and LARGE in the organization of the dystrophin-glycoprotein complex in muscle sarcolemma, we generated double-mutant mice for the dystrophin and LARGE proteins. The new Dmdmdx/Largemyd mouse model is viable and shows a severe phenotype that is associated with the lack of dystrophin in muscle. We tested the usefulness of our new mouse model for cell therapy by systemically injecting them with normal murine mesenchymal adipose stem cells (mASCs. We verified that the mASCs were hosted in the dystrophic muscle. The new mouse model has proven to be very useful for the study of several other therapies, because injected cells can be screened both through DNA and protein analysis. Study of its substantial muscle weakness will also be very informative in the evaluation of functional benefits of these therapies.

Dual delivery of rhPDGF-BB and bone marrow mesenchymal stromal cells expressing the BMP2 gene enhance bone formation in a critical-sized defect model.

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Park, Shin-Young; Kim, Kyoung-Hwa; Shin, Seung-Yun; Koo, Ki-Tae; Lee, Yong-Moo; Seol, Yang-Jo

2013-11-01

Bone tissue healing is a dynamic, orchestrated process that relies on multiple growth factors and cell types. Platelet-derived growth factor-BB (PDGF-BB) is released from platelets at wound sites and induces cellular migration and proliferation necessary for bone regeneration in the early healing process. Bone morphogenetic protein-2 (BMP-2), the most potent osteogenic differentiation inducer, directs new bone formation at the sites of bone defects. This study evaluated a combinatorial treatment protocol of PDGF-BB and BMP-2 on bone healing in a critical-sized defect model. To mimic the bone tissue healing process, a dual delivery approach was designed to deliver the rhPDGF-BB protein transiently during the early healing phase, whereas BMP-2 was supplied by rat bone marrow stromal cells (BMSCs) transfected with an adenoviral vector containing the BMP2 gene (AdBMP2) for prolonged release throughout the healing process. In in vitro experiments, the dual delivery of rhPDGF-BB and BMP2 significantly enhanced cell proliferation. However, the osteogenic differentiation of BMSCs was significantly suppressed even though the amount of BMP-2 secreted by the AdBMP2-transfected BMSCs was not significantly affected by the rhPDGF-BB treatment. In addition, dual delivery inhibited the mRNA expression of BMP receptor type II and Noggin in BMSCs. In in vivo experiments, critical-sized calvarial defects in rats showed enhanced bone regeneration by dual delivery of autologous AdBMP2-transfected BMSCs and rhPDGF-BB in both the amount of new bone formed and the bone mineral density. These enhancements in bone regeneration were greater than those observed in the group treated with AdBMP2-transfected BMSCs alone. In conclusion, the dual delivery of rhPDGF-BB and AdBMP2-transfected BMSCs improved the quality of the regenerated bone, possibly due to the modulation of PDGF-BB on BMP-2-induced osteogenesis.

Effects of in-cascade defect clustering on near-term defect evolution

Energy Technology Data Exchange (ETDEWEB)

Heinisch, H.L. [Pacific Northwest National Lab., Richland, WA (United States)

1997-08-01

The effects of in-cascade defect clustering on the nature of the subsequent defect population are being studied using stochastic annealing simulations applied to cascades generated in molecular dynamics (MD) simulations. The results of the simulations illustrates the strong influence of the defect configuration existing in the primary damage state on subsequent defect evolution. The large differences in mobility and stability of vacancy and interstitial defects and the rapid one-dimensional diffusion of small, glissile interstitial loops produced directly in cascades have been shown to be significant factors affecting the evolution of the defect distribution. In recent work, the effects of initial cluster sizes appear to be extremely important.

A brain-specific gene cluster isolated from the region of the mouse obesity locus is expressed in the adult hypothalamus and during mouse development

Energy Technology Data Exchange (ETDEWEB)

Laig-Webster, M.; Lim, M.E.; Chehab, F.F. [Univ. of California, San Francisco, CA (United States)

1994-09-01

The molecular defect underlying an autosomal recessive form of genetic obesity in a classical mouse model C57 BL/6J-ob/ob has not yet been elucidated. Whereas metabolic and physiological disturbances such as diabetes and hypertension are associated with obesity, the site of expression and the nature of the primary lesion responsible for this cascade of events remains elusive. Our efforts aimed at the positional cloning of the ob gene by YAC contig mapping and gene identification have resulted in the cloning of a brain-specific gene cluster from the ob critical region. The expression of this gene cluster is remarkably complex owing to the multitude of brain-specific mRNA transcripts detected on Northern blots. cDNA cloning of these transcripts suggests that they are expressed from different genes as well as by alternate splicing mechanisms. Furthermore, the genomic organization of the cluster appears to consist of at least two identical promoters displaying CpG islands characteristic of housekeeping genes, yet clearly involving tissue-specific expression. Sense and anti-sense synthetic RNA probes were derived from a common DNA sequence on 3 cDNA clones and hybridized to 8-16 days mouse embryonic stages and mouse adult brain sections. Expression in development was noticeable as of the 11th day of gestation and confined to the central nervous system mainly in the telencephalon and spinal cord. Coronal and sagittal sections of the adult mouse brain showed expression only in 3 different regions of the brain stem. In situ hybridization to mouse hypothalamus sections revealed the presence of a localized and specialized group of cells expressing high levels of mRNA, suggesting that this gene cluster may also be involved in the regulation of hypothalamic activities. The hypothalamus has long been hypothesized as a primary candidate tissue for the expression of the obesity gene mainly because of its well-established role in the regulation of energy metabolism and food intake.

Progressive Impairment of Lactate-based Gluconeogenesis in the Huntington?s Disease Mouse Model R6/2

OpenAIRE

Nielsen, Signe Marie Borch; Hasholt, Lis; N?rrem?lle, Anne; Josefsen, Knud

2015-01-01

Huntington?s disease (HD) is a neurodegenerative illness, where selective neuronal loss in the brain caused by expression of mutant huntingtin protein leads to motor dysfunction and cognitive decline in addition to peripheral metabolic changes. In this study we confirm our previous observation of impairment of lactate-based hepatic gluconeogenesis in the transgenic HD mouse model R6/2 and determine that the defect manifests very early and progresses in severity with disease development, indic...

Alterations to dendritic spine morphology, but not dendrite patterning, of cortical projection neurons in Tc1 and Ts1Rhr mouse models of Down syndrome.

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Matilda A Haas

Full Text Available Down Syndrome (DS is a highly prevalent developmental disorder, affecting 1/700 births. Intellectual disability, which affects learning and memory, is present in all cases and is reflected by below average IQ. We sought to determine whether defective morphology and connectivity in neurons of the cerebral cortex may underlie the cognitive deficits that have been described in two mouse models of DS, the Tc1 and Ts1Rhr mouse lines. We utilised in utero electroporation to label a cohort of future upper layer projection neurons in the cerebral cortex of developing mouse embryos with GFP, and then examined neuronal positioning and morphology in early adulthood, which revealed no alterations in cortical layer position or morphology in either Tc1 or Ts1Rhr mouse cortex. The number of dendrites, as well as dendrite length and branching was normal in both DS models, compared with wildtype controls. The sites of projection neuron synaptic inputs, dendritic spines, were analysed in Tc1 and Ts1Rhr cortex at three weeks and three months after birth, and significant changes in spine morphology were observed in both mouse lines. Ts1Rhr mice had significantly fewer thin spines at three weeks of age. At three months of age Tc1 mice had significantly fewer mushroom spines--the morphology associated with established synaptic inputs and learning and memory. The decrease in mushroom spines was accompanied by a significant increase in the number of stubby spines. This data suggests that dendritic spine abnormalities may be a more important contributor to cognitive deficits in DS models, rather than overall neuronal architecture defects.

Dirichlet topological defects

International Nuclear Information System (INIS)

Carroll, S.M.; Trodden, M.

1998-01-01

We propose a class of field theories featuring solitonic solutions in which topological defects can end when they intersect other defects of equal or higher dimensionality. Such configurations may be termed open-quotes Dirichlet topological defects,close quotes in analogy with the D-branes of string theory. Our discussion focuses on defects in scalar field theories with either gauge or global symmetries, in 3+1 dimensions; the types of defects considered include walls ending on walls, strings on walls, and strings on strings. copyright 1998 The American Physical Society

More than a bystander: the contributions of intrinsic skeletal muscle defects in motor neuron diseases.

Science.gov (United States)

Boyer, Justin G; Ferrier, Andrew; Kothary, Rashmi

2013-12-18

Spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS), and spinal-bulbar muscular atrophy (SBMA) are devastating diseases characterized by the degeneration of motor neurons. Although the molecular causes underlying these diseases differ, recent findings have highlighted the contribution of intrinsic skeletal muscle defects in motor neuron diseases. The use of cell culture and animal models has led to the important finding that muscle defects occur prior to and independently of motor neuron degeneration in motor neuron diseases. In SMA for instance, the muscle specific requirements of the SMA disease-causing gene have been demonstrated by a series of genetic rescue experiments in SMA models. Conditional ALS mouse models expressing a muscle specific mutant SOD1 gene develop atrophy and muscle degeneration in the absence of motor neuron pathology. Treating SBMA mice by over-expressing IGF-1 in a skeletal muscle-specific manner attenuates disease severity and improves motor neuron pathology. In the present review, we provide an in depth description of muscle intrinsic defects, and discuss how they impact muscle function in these diseases. Furthermore, we discuss muscle-specific therapeutic strategies used to treat animal models of SMA, ALS, and SBMA. The study of intrinsic skeletal muscle defects is crucial for the understanding of the pathophysiology of these diseases and will open new therapeutic options for the treatment of motor neuron diseases.

A Mathematical Model of Skeletal Muscle Disease and Immune Response in the mdx Mouse

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Abdul Salam Jarrah

2014-01-01

Full Text Available Duchenne muscular dystrophy (DMD is a genetic disease that results in the death of affected boys by early adulthood. The genetic defect responsible for DMD has been known for over 25 years, yet at present there is neither cure nor effective treatment for DMD. During early disease onset, the mdx mouse has been validated as an animal model for DMD and use of this model has led to valuable but incomplete insights into the disease process. For example, immune cells are thought to be responsible for a significant portion of muscle cell death in the mdx mouse; however, the role and time course of the immune response in the dystrophic process have not been well described. In this paper we constructed a simple mathematical model to investigate the role of the immune response in muscle degeneration and subsequent regeneration in the mdx mouse model of Duchenne muscular dystrophy. Our model suggests that the immune response contributes substantially to the muscle degeneration and regeneration processes. Furthermore, the analysis of the model predicts that the immune system response oscillates throughout the life of the mice, and the damaged fibers are never completely cleared.

mTOR complex 2 phosphorylates IMP1 cotranslationally to promote IGF2 production and the proliferation of mouse embryonic fibroblasts

DEFF Research Database (Denmark)

Dai, Ning; Christiansen, Jan; Nielsen, Finn

2013-01-01

uncover a new mechanism by which mTOR regulates organismal growth by promoting IGF2 production in the mouse embryo through mTORC2-catalyzed cotranslational IMP1/IMP3 phosphorylation. Inasmuch as TORC2 is activated by association with ribosomes, the present results indicate that mTORC2-catalyzed...... production, and diminished proliferation. The proliferation of the IMP1-null fibroblasts can be restored to wild-type levels by IGF2 in vitro or by re-expression of IMP1, which corrects the defects in IGF2 RNA splicing and translation. The ability of IMP1 to correct these defects is dependent on IMP1...

Deficiency of RITA results in multiple mitotic defects by affecting microtubule dynamics.

Science.gov (United States)

Steinhäuser, K; Klöble, P; Kreis, N-N; Ritter, A; Friemel, A; Roth, S; Reichel, J M; Michaelis, J; Rieger, M A; Louwen, F; Oswald, F; Yuan, J

2017-04-01

Deregulation of mitotic microtubule (MT) dynamics results in defective spindle assembly and chromosome missegregation, leading further to chromosome instability, a hallmark of tumor cells. RBP-J interacting and tubulin-associated protein (RITA) has been identified as a negative regulator of the Notch signaling pathway. Intriguingly, deregulated RITA is involved in primary hepatocellular carcinoma and other malignant entities. We were interested in the potential molecular mechanisms behind its involvement. We show here that RITA binds to tubulin and localizes to various mitotic MT structures. RITA coats MTs and affects their structures in vitro as well as in vivo. Tumor cell lines deficient of RITA display increased acetylated α-tubulin, enhanced MT stability and reduced MT dynamics, accompanied by multiple mitotic defects, including chromosome misalignment and segregation errors. Re-expression of wild-type RITA, but not RITA Δtub ineffectively binding to tubulin, restores the phenotypes, suggesting that the role of RITA in MT modulation is mediated via its interaction with tubulin. Mechanistically, RITA interacts with tubulin/histone deacetylase 6 (HDAC6) and its suppression decreases the binding of the deacetylase HDAC6 to tubulin/MTs. Furthermore, the mitotic defects and increased MT stability are also observed in RITA -/- mouse embryonic fibroblasts. RITA has thus a novel role in modulating MT dynamics and its deregulation results in erroneous chromosome segregation, one of the major reasons for chromosome instability in tumor cells.

Defective propagation of signals generated by sympathetic nerve stimulation in the liver of connexin32-deficient mice.

Science.gov (United States)

Nelles, E; Bützler, C; Jung, D; Temme, A; Gabriel, H D; Dahl, U; Traub, O; Stümpel, F; Jungermann, K; Zielasek, J; Toyka, K V; Dermietzel, R; Willecke, K

1996-09-03

The gap junctional protein connexin32 is expressed in hepatocytes, exocrine pancreatic cells, Schwann cells, and other cell types. We have inactivated the connexin32 gene by homologous recombination in the mouse genome and have generated homozygous connexin32-deficient mice that were viable and fertile but weighed on the average approximately 17% less than wild-type controls. Electrical stimulation of sympathetic nerves in connexin32-deficient liver triggered a 78% lower amount of glucose mobilization from glycogen stores, when compared with wild-type liver. Thus, connexin32-containing gap junctions are essential in mouse liver for maximal intercellular propagation of the noradrenaline signal from the periportal (upstream) area, where it is received from sympathetic nerve endings, to perivenous (downstream) hepatocytes. In connexin32-defective liver, the amount of connexin26 protein expressed was found to be lower than in wild-type liver, and the total area of gap junction plaques was approximately 1000-fold smaller than in wild-type liver. In contrast to patients with connexin32 defects suffering from X chromosome-linked Charcot-Marie-Tooth disease (CMTX) due to demyelination in Schwann cells of peripheral nerves, connexin32-deficient mice did not show neurological abnormalities when analyzed at 3 months of age. It is possible, however, that they may develop neurodegenerative symptoms at older age.

Defect forces, defect couples and path integrals in fracture mechanics

International Nuclear Information System (INIS)

Roche, R.L.

1979-07-01

In this work, it is shown that the path integrals can be introduced without any reference to the material behavior. The method is based on the definition in a continuous medium of a set of vectors and couples having the dimension of a force or a moment. More precisely, definitions are given of volume defect forces, surface defect forces, volume defect couples, and surface defect couples. This is done with the help of the stress working variation of a particule moving through the solid. The most important result is: the resultant of all the defect forces included in a volume V is the J integral on the surface surrounding V and the moment resultant is the L integral. So these integrals are defined without any assumption on the material constitutive equation. Another result is the material form of the virtual work principle - defect forces are acting like conventional forces in the conventional principles of virtual work. This lead to the introduction of the energy momentum tensor and of the associated couple stress. Application of this method is made to fracture mechanics in studying the defect forces distribution around a crack [fr

Omcg1 is critically required for mitosis in rapidly dividing mouse intestinal progenitors and embryonic stem cells.

Science.gov (United States)

Léguillier, Teddy; Vandormael-Pournin, Sandrine; Artus, Jérôme; Houlard, Martin; Picard, Christel; Bernex, Florence; Robine, Sylvie; Cohen-Tannoudji, Michel

2012-07-15

Recent studies have shown that factors involved in transcription-coupled mRNA processing are important for the maintenance of genome integrity. How these processes are linked and regulated in vivo remains largely unknown. In this study, we addressed in the mouse model the function of Omcg1, which has been shown to participate in co-transcriptional processes, including splicing and transcription-coupled repair. Using inducible mouse models, we found that Omcg1 is most critically required in intestinal progenitors. In absence of OMCG1, proliferating intestinal epithelial cells underwent abnormal mitosis followed by apoptotic cell death. As a consequence, the crypt proliferative compartment of the small intestine was quickly and totally abrogated leading to the rapid death of the mice. Lack of OMCG1 in embryonic stem cells led to a similar cellular phenotype, with multiple mitotic defects and rapid cell death. We showed that mutant intestinal progenitors and embryonic stem cells exhibited a reduced cell cycle arrest following irradiation, suggesting that mitotic defects may be consecutive to M phase entry with unrepaired DNA damages. These findings unravel a crucial role for pre-mRNA processing in the homeostasis of the small intestine and point to a major role of OMCG1 in the maintenance of genome integrity.

Omcg1 is critically required for mitosis in rapidly dividing mouse intestinal progenitors and embryonic stem cells

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Teddy Léguillier

2012-05-01

Recent studies have shown that factors involved in transcription-coupled mRNA processing are important for the maintenance of genome integrity. How these processes are linked and regulated in vivo remains largely unknown. In this study, we addressed in the mouse model the function of Omcg1, which has been shown to participate in co-transcriptional processes, including splicing and transcription-coupled repair. Using inducible mouse models, we found that Omcg1 is most critically required in intestinal progenitors. In absence of OMCG1, proliferating intestinal epithelial cells underwent abnormal mitosis followed by apoptotic cell death. As a consequence, the crypt proliferative compartment of the small intestine was quickly and totally abrogated leading to the rapid death of the mice. Lack of OMCG1 in embryonic stem cells led to a similar cellular phenotype, with multiple mitotic defects and rapid cell death. We showed that mutant intestinal progenitors and embryonic stem cells exhibited a reduced cell cycle arrest following irradiation, suggesting that mitotic defects may be consecutive to M phase entry with unrepaired DNA damages. These findings unravel a crucial role for pre-mRNA processing in the homeostasis of the small intestine and point to a major role of OMCG1 in the maintenance of genome integrity.

Neural Tube Defects

Science.gov (United States)

Neural tube defects are birth defects of the brain, spine, or spinal cord. They happen in the ... that she is pregnant. The two most common neural tube defects are spina bifida and anencephaly. In ...

Ultra-high frequency ultrasound biomicroscopy and high throughput cardiovascular phenotyping in a large scale mouse mutagenesis screen

Science.gov (United States)

Liu, Xiaoqin; Francis, Richard; Tobita, Kimimasa; Kim, Andy; Leatherbury, Linda; Lo, Cecilia W.

2013-02-01

Ultrasound biomicroscopy (UBM) is ideally suited for phenotyping fetal mice for congenital heart disease (CHD), as imaging can be carried out noninvasively to provide both hemodynamic and structural information essential for CHD diagnosis. Using the UBM (Vevo 2100; 40Hz) in conjunction with the clinical ultrasound system (Acuson Sequioa C512; 15Hz), we developed a two-step screening protocol to scan thousands fetuses derived from ENU mutagenized pedigrees. A wide spectrum of CHD was detected by the UBM, which were subsequently confirmed with follow-up necropsy and histopathology examination with episcopic fluorescence image capture. CHD observed included outflow anomalies, left/right heart obstructive lesions, septal/valvular defects and cardiac situs anomalies. Meanwhile, various extracardiac defects were found, such as polydactyly, craniofacial defects, exencephaly, omphalocele-cleft palate, most of which were associated with cardiac defects. Our analyses showed the UBM was better at assessing cardiac structure and blood flow profiles, while conventional ultrasound allowed higher throughput low-resolution screening. Our study showed the integration of conventional clinical ultrasound imaging with the UBM for fetal mouse cardiovascular phenotyping can maximize the detection and recovery of CHD mutants.

COMP-angiopoietin 1 increases proliferation, differentiation, and migration of stem-like cells through Tie-2-mediated activation of p38 MAPK and PI3K/Akt signal transduction pathways

Energy Technology Data Exchange (ETDEWEB)

Kook, Sung-Ho [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Lim, Shin-Saeng [School of Dentistry and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Kwon, Jungkee [College of Veterinary Medicine, Chonbuk National University, Jeonju (Korea, Republic of); Hwang, Jae-Won; Bae, Cheol-Hyeon [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of); Seo, Young-Kwon [Research Institute of Biotechnology, Dongguk University, Seoul (Korea, Republic of); Lee, Jeong-Chae, E-mail: leejc88@jbnu.ac.kr [Cluster for Craniofacial Development and Regeneration Research, Institute of Oral Biosciences and School of Dentistry, Chonbuk National University, Jeonju (Korea, Republic of)

2014-12-12

Highlights: • COMP-Ang1 induces Tie-2 activation in BMMSCs, but not in primary osteoblasts. • Tie-2 knockdown inhibits COMP-Ang1-stimulated proliferation and osteoblastogenesis. • Tie-2 knockdown prevents COMP-Ang1-induced activation of PI3K/Akt and p38 MAPK. • COMP-Ang1 induces migration of cells via activation of PI3K/Akt and CXCR4 pathways. • COMP-Ang1 stimulates in vivo migration of PDLSCs into a calvarial defect site of rats. - Abstract: Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent capable of inducing the homing of cells with increased angiogenesis. However, the potentials of COMP-Ang1 to stimulate migration of mesenchymal stem cells (MSCs) and the associated mechanisms are not completely understood. We examined the potential of COMP-Ang1 on bone marrow (BM)-MSCs, human periodontal ligament stem cells (PDLSCs), and calvarial osteoblasts. COMP-Ang1 augmented Tie-2 induction at protein and mRNA levels and increased proliferation and expression of runt-related transcription factor 2 (Runx2), osterix, and CXCR4 in BMMSCs, but not in osteoblasts. The COMP-Ang1-mediated increases were inhibited by Tie-2 knockdown and by treating inhibitors of phosphoinositide 3-kinase (PI3K), LY294002, or p38 mitogen-activated protein kinase (MAPK), SB203580. Phosphorylation of p38 MAPK and Akt was prevented by siRNA-mediated silencing of Tie-2. COMP-Ang1 also induced in vitro migration of BMMSCs and PDLSCs. The induced migration was suppressed by Tie-2 knockdown and by CXCR4-specific peptide antagonist or LY294002, but not by SB203580. Furthermore, COMP-Ang1 stimulated the migration of PDLSCs into calvarial defect site of rats. Collectively, our results demonstrate that COMP-Ang1-stimulated proliferation, differentiation, and migration of progenitor cells may involve the Tie-2-mediated activation of p38 MAPK and PI3K/Akt pathways.

COMP-angiopoietin 1 increases proliferation, differentiation, and migration of stem-like cells through Tie-2-mediated activation of p38 MAPK and PI3K/Akt signal transduction pathways

International Nuclear Information System (INIS)

Kook, Sung-Ho; Lim, Shin-Saeng; Cho, Eui-Sic; Lee, Young-Hoon; Han, Seong-Kyu; Lee, Kyung-Yeol; Kwon, Jungkee; Hwang, Jae-Won; Bae, Cheol-Hyeon; Seo, Young-Kwon; Lee, Jeong-Chae

2014-01-01

Highlights: • COMP-Ang1 induces Tie-2 activation in BMMSCs, but not in primary osteoblasts. • Tie-2 knockdown inhibits COMP-Ang1-stimulated proliferation and osteoblastogenesis. • Tie-2 knockdown prevents COMP-Ang1-induced activation of PI3K/Akt and p38 MAPK. • COMP-Ang1 induces migration of cells via activation of PI3K/Akt and CXCR4 pathways. • COMP-Ang1 stimulates in vivo migration of PDLSCs into a calvarial defect site of rats. - Abstract: Recombinant COMP-Ang1, a chimera of angiopoietin-1 (Ang1) and a short coiled-coil domain of cartilage oligomeric matrix protein (COMP), is under consideration as a therapeutic agent capable of inducing the homing of cells with increased angiogenesis. However, the potentials of COMP-Ang1 to stimulate migration of mesenchymal stem cells (MSCs) and the associated mechanisms are not completely understood. We examined the potential of COMP-Ang1 on bone marrow (BM)-MSCs, human periodontal ligament stem cells (PDLSCs), and calvarial osteoblasts. COMP-Ang1 augmented Tie-2 induction at protein and mRNA levels and increased proliferation and expression of runt-related transcription factor 2 (Runx2), osterix, and CXCR4 in BMMSCs, but not in osteoblasts. The COMP-Ang1-mediated increases were inhibited by Tie-2 knockdown and by treating inhibitors of phosphoinositide 3-kinase (PI3K), LY294002, or p38 mitogen-activated protein kinase (MAPK), SB203580. Phosphorylation of p38 MAPK and Akt was prevented by siRNA-mediated silencing of Tie-2. COMP-Ang1 also induced in vitro migration of BMMSCs and PDLSCs. The induced migration was suppressed by Tie-2 knockdown and by CXCR4-specific peptide antagonist or LY294002, but not by SB203580. Furthermore, COMP-Ang1 stimulated the migration of PDLSCs into calvarial defect site of rats. Collectively, our results demonstrate that COMP-Ang1-stimulated proliferation, differentiation, and migration of progenitor cells may involve the Tie-2-mediated activation of p38 MAPK and PI3K/Akt pathways

Developmental immunolocalization of the Klotho protein in mouse kidney epithelial cells

Directory of Open Access Journals (Sweden)

J.H. Song

2014-01-01

Full Text Available A defect in Klotho gene expression in the mouse results in a syndrome that resembles rapid human aging. In this study, we investigated the detailed distribution and the time of the first appearance of Klotho in developing and adult mouse kidney. Kidneys from 16-(F16, 18-(F18 and 20-day-old (F20 fetuses, 1- (P1, 4- (P4, 7- (P7, 14- (P14, and 21-day-old (P21 pups and adults were processed for immunohistochemistry and immunoblot analyses. In the developing mouse kidney, Klotho immunoreactivity was initially observed in a few cells of the connecting tubules (CNT of 18-day-old fetus (F and in the medullary collecting duct (MCD and distal nephron of the F16 developing kidney. In F20, Klotho immunoreactivity was increased in CNT and additionally observed in the outer portion of MCD and tip of the renal papilla. During the first 3 weeks after birth, Klotho-positive cells gradually disappeared from the MCD due to apoptosis, but remained in the CNT and cortical collecting ducts (CCD. In the adult mouse, the Klotho protein was expressed only in a few cells of the CNT and CCD in cortical area. Also, Klotho immunoreactivity was observed in the aquaporin 2-positive CNT, CCD, and NaCl co-transporter-positive distal convoluted tubule (DCT cells and type B and nonA-nonB intercalated cells of CNT, DCT, and CCD. Collectively, our data indicate that immunolocalization of Klotho is closely correlated with proliferation in the intercalated cells of CNT and CCD from aging, and may be involved in the regulation of tubular proliferation.

Multiscale, Converging Defects of Macro-Porosity, Microstructure and Matrix Mineralization Impact Long Bone Fragility in NF1

Science.gov (United States)

Kühnisch, Jirko; Seto, Jong; Lange, Claudia; Schrof, Susanne; Stumpp, Sabine; Kobus, Karolina; Grohmann, Julia; Kossler, Nadine; Varga, Peter; Osswald, Monika; Emmerich, Denise; Tinschert, Sigrid; Thielemann, Falk; Duda, Georg; Seifert, Wenke; el Khassawna, Thaqif; Stevenson, David A.; Elefteriou, Florent; Kornak, Uwe; Raum, Kay; Fratzl, Peter; Mundlos, Stefan; Kolanczyk, Mateusz

2014-01-01

Bone fragility due to osteopenia, osteoporosis or debilitating focal skeletal dysplasias is a frequent observation in the Mendelian disease Neurofibromatosis type 1 (NF1). To determine the mechanisms underlying bone fragility in NF1 we analyzed two conditional mouse models, Nf1Prx1 (limb knock-out) and Nf1Col1 (osteoblast specific knock-out), as well as cortical bone samples from individuals with NF1. We examined mouse bone tissue with micro-computed tomography, qualitative and quantitative histology, mechanical tensile analysis, small-angle X-ray scattering (SAXS), energy dispersive X-ray spectroscopy (EDX), and scanning acoustic microscopy (SAM). In cortical bone of Nf1Prx1 mice we detected ectopic blood vessels that were associated with diaphyseal mineralization defects. Defective mineral binding in the proximity of blood vessels was most likely due to impaired bone collagen formation, as these areas were completely devoid of acidic matrix proteins and contained thin collagen fibers. Additionally, we found significantly reduced mechanical strength of the bone material, which was partially caused by increased osteocyte volume. Consistent with these observations, bone samples from individuals with NF1 and tibial dysplasia showed increased osteocyte lacuna volume. Reduced mechanical properties were associated with diminished matrix stiffness, as determined by SAM. In line with these observations, bone tissue from individuals with NF1 and tibial dysplasia showed heterogeneous mineralization and reduced collagen fiber thickness and packaging. Collectively, the data indicate that bone fragility in NF1 tibial dysplasia is partly due to an increased osteocyte-related micro-porosity, hypomineralization, a generalized defect of organic matrix formation, exacerbated in the regions of tensional and bending force integration, and finally persistence of ectopic blood vessels associated with localized macro-porotic bone lesions. PMID:24465906

Regulation of gap junction function and Connexin 43 expression by cytochrome P450 oxidoreductase (CYPOR)

Energy Technology Data Exchange (ETDEWEB)

Polusani, Srikanth R.; Kar, Rekha; Riquelme, Manuel A.; Masters, Bettie Sue [The University of Texas Health Science Center at San Antonio, Department of Biochemistry, San Antonio, TX 78229 (United States); Panda, Satya P., E-mail: panda@uthscsa.edu [The University of Texas Health Science Center at San Antonio, Department of Biochemistry, San Antonio, TX 78229 (United States)

2011-08-05

Highlights: {yields} Humans with severe forms of cytochrome P450 oxidoreductase (CYPOR) mutations show bone defects as observed in Antley-Bixler Syndrome. {yields} First report showing knockdown of CYPOR in osteoblasts decreased Connexin 43 (Cx43) protein levels. Cx43 is known to play an important role in bone modeling. {yields} Knockdown of CYPOR decreased Gap Junctional Intercellular Communication and hemichannel activity. {yields} Knockdown of CYPOR decreased Cx43 in mouse primary calvarial osteoblasts. {yields} Decreased Cx43 expression was observed at the transcriptional level. -- Abstract: Cytochrome P450 oxidoreductase (CYPOR) is a microsomal electron-transferring enzyme containing both FAD and FMN as co-factors, which provides the reducing equivalents to various redox partners, such as cytochromes P450 (CYPs), heme oxygenase (HO), cytochrome b{sub 5} and squalene monooxygenase. Human patients with severe forms of CYPOR mutation show bone defects such as cranio- and humeroradial synostoses and long bone fractures, known as Antley-Bixler-like Syndrome (ABS). To elucidate the role of CYPOR in bone, we knocked-down CYPOR in multiple osteoblast cell lines using RNAi technology. In this study, knock-down of CYPOR decreased the expression of Connexin 43 (Cx43), known to play a critical role in bone formation, modeling, and remodeling. Knock-down of CYPOR also decreased Gap Junction Intercellular Communication (GJIC) and hemichannel activity. Promoter luciferase assays revealed that the decrease in expression of Cx43 in CYPOR knock-down cells was due to transcriptional repression. Primary osteoblasts isolated from bone specific Por knock-down mice calvariae confirmed the findings in the cell lines. Taken together, our study provides novel insights into the regulation of gap junction function by CYPOR and suggests that Cx43 may play an important role(s) in CYPOR-mediated bone defects seen in patients.

Regulation of gap junction function and Connexin 43 expression by cytochrome P450 oxidoreductase (CYPOR)

International Nuclear Information System (INIS)

Polusani, Srikanth R.; Kar, Rekha; Riquelme, Manuel A.; Masters, Bettie Sue; Panda, Satya P.

2011-01-01

Highlights: → Humans with severe forms of cytochrome P450 oxidoreductase (CYPOR) mutations show bone defects as observed in Antley-Bixler Syndrome. → First report showing knockdown of CYPOR in osteoblasts decreased Connexin 43 (Cx43) protein levels. Cx43 is known to play an important role in bone modeling. → Knockdown of CYPOR decreased Gap Junctional Intercellular Communication and hemichannel activity. → Knockdown of CYPOR decreased Cx43 in mouse primary calvarial osteoblasts. → Decreased Cx43 expression was observed at the transcriptional level. -- Abstract: Cytochrome P450 oxidoreductase (CYPOR) is a microsomal electron-transferring enzyme containing both FAD and FMN as co-factors, which provides the reducing equivalents to various redox partners, such as cytochromes P450 (CYPs), heme oxygenase (HO), cytochrome b 5 and squalene monooxygenase. Human patients with severe forms of CYPOR mutation show bone defects such as cranio- and humeroradial synostoses and long bone fractures, known as Antley-Bixler-like Syndrome (ABS). To elucidate the role of CYPOR in bone, we knocked-down CYPOR in multiple osteoblast cell lines using RNAi technology. In this study, knock-down of CYPOR decreased the expression of Connexin 43 (Cx43), known to play a critical role in bone formation, modeling, and remodeling. Knock-down of CYPOR also decreased Gap Junction Intercellular Communication (GJIC) and hemichannel activity. Promoter luciferase assays revealed that the decrease in expression of Cx43 in CYPOR knock-down cells was due to transcriptional repression. Primary osteoblasts isolated from bone specific Por knock-down mice calvariae confirmed the findings in the cell lines. Taken together, our study provides novel insights into the regulation of gap junction function by CYPOR and suggests that Cx43 may play an important role(s) in CYPOR-mediated bone defects seen in patients.

Mouse allergen exposure and immunologic responses: IgE-mediated mouse sensitization and mouse specific IgG and IgG4 levels

NARCIS (Netherlands)

Matsui, Elizabeth C.; Krop, Esmeralda J. M.; Diette, Gregory B.; Aalberse, Rob C.; Smith, Abigail L.; Eggleston, Peyton A.

2004-01-01

Although there is evidence that contact with mice is associated with IgE-mediated mouse sensitization and mouse specific antibody responses, the exposure-response relationships remain unclear. To determine whether IgE-mediated mouse sensitization and mouse specific IgG (mIgG) and mIgG4 levels

Sperm calcineurin inhibition prevents mouse fertility with implications for male contraceptive.

Science.gov (United States)

Miyata, Haruhiko; Satouh, Yuhkoh; Mashiko, Daisuke; Muto, Masanaga; Nozawa, Kaori; Shiba, Kogiku; Fujihara, Yoshitaka; Isotani, Ayako; Inaba, Kazuo; Ikawa, Masahito

2015-10-23

Calcineurin inhibitors, such as cyclosporine A and FK506, are used as immunosuppressant drugs, but their adverse effects on male reproductive function remain unclear. The testis expresses somatic calcineurin and a sperm-specific isoform that contains a catalytic subunit (PPP3CC) and a regulatory subunit (PPP3R2). We demonstrate herein that male mice lacking Ppp3cc or Ppp3r2 genes (knockout mice) are infertile, with reduced sperm motility owing to an inflexible midpiece. Treatment of mice with cyclosporine A or FK506 creates phenocopies of the sperm motility and morphological defects. These defects appear within 4 to 5 days of treatment, which indicates that sperm-specific calcineurin confers midpiece flexibility during epididymal transit. Male mouse fertility recovered a week after we discontinued treatment. Because human spermatozoa contain PPP3CC and PPP3R2 as a form of calcineurin, inhibition of this sperm-specific calcineurin may lead to the development of a reversible male contraceptive that would target spermatozoa in the epididymis. Copyright © 2015, American Association for the Advancement of Science.

On holographic defect entropy

International Nuclear Information System (INIS)

Estes, John; Jensen, Kristan; O’Bannon, Andy; Tsatis, Efstratios; Wrase, Timm

2014-01-01

We study a number of (3+1)- and (2+1)-dimensional defect and boundary conformal field theories holographically dual to supergravity theories. In all cases the defects or boundaries are planar, and the defects are codimension-one. Using holography, we compute the entanglement entropy of a (hemi-)spherical region centered on the defect (boundary). We define defect and boundary entropies from the entanglement entropy by an appropriate background subtraction. For some (3+1)-dimensional theories we find evidence that the defect/boundary entropy changes monotonically under certain renormalization group flows triggered by operators localized at the defect or boundary. This provides evidence that the g-theorem of (1+1)-dimensional field theories generalizes to higher dimensions

VPS35 regulates developing mouse hippocampal neuronal morphogenesis by promoting retrograde trafficking of BACE1

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Chun-Lei Wang

2012-10-01

VPS35, a major component of the retromer, plays an important role in the selective endosome-to-Golgi retrieval of membrane proteins. Dysfunction of retromer is a risk factor for neurodegenerative disorders, but its function in developing mouse brain remains poorly understood. Here we provide evidence for VPS35 promoting dendritic growth and maturation, and axonal protein transport in developing mouse hippocampal neurons. Embryonic hippocampal CA1 neurons suppressing Vps35 expression by in utero electroporation of its micro RNAs displayed shortened apical dendrites, reduced dendritic spines, and swollen commissural axons in the neonatal stage, those deficits reflecting a defective protein transport/trafficking in developing mouse neurons. Further mechanistic studies showed that Vps35 depletion in neurons resulted in an impaired retrograde trafficking of BACE1 (β1-secretase and altered BACE1 distribution. Suppression of BACE1 expression in CA1 neurons partially rescued both dendritic and axonal deficits induced by Vps35-deficiency. These results thus demonstrate that BACE1 acts as a critical cargo of retromer in vitro and in vivo, and suggest that VPS35 plays an essential role in regulating apical dendritic maturation and in preventing axonal spheroid formation in developing hippocampal neurons.

Defects in semiconductors

CERN Document Server

Romano, Lucia; Jagadish, Chennupati

2015-01-01

This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoret

Epigenetic transgenerational inheritance of vinclozolin induced mouse adult onset disease and associated sperm epigenome biomarkers.

Science.gov (United States)

Guerrero-Bosagna, Carlos; Covert, Trevor R; Haque, Md M; Settles, Matthew; Nilsson, Eric E; Anway, Matthew D; Skinner, Michael K

2012-12-01

The endocrine disruptor vinclozolin has previously been shown to promote epigenetic transgenerational inheritance of adult onset disease in the rat. The current study was designed to investigate the transgenerational actions of vinclozolin on the mouse. Transient exposure of the F0 generation gestating female during gonadal sex determination promoted transgenerational adult onset disease in F3 generation male and female mice, including spermatogenic cell defects, testicular abnormalities, prostate abnormalities, kidney abnormalities and polycystic ovarian disease. Pathology analysis demonstrated 75% of the vinclozolin lineage animals developed disease with 34% having two or more different disease states. Interestingly, the vinclozolin induced transgenerational disease was observed in the outbred CD-1 strain, but not the inbred 129 mouse strain. Analysis of the F3 generation sperm epigenome identified differential DNA methylation regions that can potentially be utilized as epigenetic biomarkers for transgenerational exposure and disease. Copyright © 2012 Elsevier Inc. All rights reserved.

Birth Defects Associated with Perturbations in Pre-implantation, Gastrulation & Axis Extension: from Conjoined Twinning to Caudal Dysgenesis

Science.gov (United States)

Ferrer-Vaquer, Anna; Hadjantonakis, Anna-Katerina

2012-01-01

Congenital malformations represent approximately 3 in 100 live births within the human population. Understanding their pathogenesis and ultimately formulating effective treatments is underpinned by knowledge of the events and factors that regulate normal embryonic development. Studies in model organisms, primarily in the mouse, the most prominent genetically tractable mammalian model, have equipped us with a rudimentary understanding of mammalian development from early lineage commitment to morphogenetic processes. In this way information provided by studies in the mouse can, in some cases, be used to draw parallels with other mammals, including human. Here we provide an overview of our current understanding of the general sequence of developmental events from early cell cleavages to gastrulation and axis extension occurring in human embryos. We will also review some of the rare birth defects occurring at these stages, in particular those resulting in conjoined twinning or caudal dysgenesis. PMID:24014416

Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

International Nuclear Information System (INIS)

Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young

2017-01-01

Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

C/EBPalpha and C/EBPbeta are required for Sebocyte differentiation and stratified squamous differentiation in adult mouse skin.

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John S House

Full Text Available C/EBPalpha and C/EBPbeta are bZIP transcription factors that are highly expressed in the interfollicular epidermis and sebaceous glands of skin and yet germ line deletion of either family member alone has only mild or no effect on keratinocyte biology and their role in sebocyte biology has never been examined. To address possible functional redundancies and reveal functional roles of C/EBPalpha and C/EBPbeta in postnatal skin, mouse models were developed in which either family member could be acutely ablated alone or together in the epidermis and sebaceous glands of adult mice. Acute removal of either C/EBPalpha or C/EBPbeta alone in adult mouse skin revealed modest to no discernable changes in epidermis or sebaceous glands. In contrast, co-ablation of C/EBPalpha and C/EBPbeta in postnatal epidermis resulted in disruption of stratified squamous differentiation characterized by hyperproliferation of basal and suprabasal keratinocytes and a defective basal to spinous keratinocyte transition involving an expanded basal compartment and a diminished and delayed spinous compartment. Acute co-ablation of C/EBPalpha and C/EBPbeta in sebaceous glands resulted in severe morphological defects, and sebocyte differentiation was blocked as determined by lack of sebum production and reduced expression of stearoyl-CoA desaturase (SCD3 and melanocortin 5 receptor (MC5R, two markers of terminal sebocyte differentiation. Specialized sebocytes of Meibomian glands and preputial glands were also affected. Our results indicate that in adult mouse skin, C/EBPalpha and C/EBPbeta are critically involved in regulating sebocyte differentiation and epidermal homeostasis involving the basal to spinous keratinocyte transition and basal cell cycle withdrawal.

Regeneration of tracheal epithelium using mouse induced pluripotent stem cells.

Science.gov (United States)

Ikeda, Masakazu; Imaizumi, Mitsuyoshi; Yoshie, Susumu; Otsuki, Koshi; Miyake, Masao; Hazama, Akihiro; Wada, Ikuo; Omori, Koichi

2016-01-01

Conclusion The findings demonstrated the potential use of induced pluripotent stem cells for regeneration of tracheal epithelium. Objective Autologous tissue implantation techniques using skin or cartilage are often applied in cases of tracheal defects with laryngeal inflammatory lesions and malignant tumor invasion. However, these techniques are invasive with an unstable clinical outcome. The purpose of this study was to investigate regeneration in a tracheal defect site of nude rats after implantation of ciliated epithelium that was differentiated from induced pluripotent stem cells. Method Embryoid bodies were formed from mouse induced pluripotent stem cells. They were cultured with growth factors for 5 days, and then cultured at the air-liquid interface. The degree of differentiation achieved prior to implantation was determined by histological findings and the results of real-time polymerase chain reaction. Embryoid bodies including ciliated epithelium were embedded into collagen gel that served as an artificial scaffold, and then implanted into nude rats, creating an 'air-liquid interface model'. Histological evaluation was performed 7 days after implantation. Results The ciliated epithelial structure survived on the lumen side of regenerated tissue. It was demonstrated histologically that the structure was composed of ciliated epithelial cells.

Understanding the Basis of Auriculocondylar Syndrome: Insights From Human and Mouse Genetic Studies

Science.gov (United States)

Clouthier, David E.; Passos Bueno, Maria Rita; Tavares, Andre L.P.; Lyonnet, Stanislas; Amiel, Jeanne; Gordon, Christopher T.

2014-01-01

Among human birth defect syndromes, malformations affecting the face are perhaps the most striking due to cultural and psychological expectations of facial shape. One such syndrome is auriculocondylar syndrome (ACS), in which patients present with defects in ear and mandible development. Affected structures arise from cranial neural crest cells, a population of cells in the embryo that reside in the pharyngeal arches and give rise to most of the bone, cartilage and connective tissue of the face. Recent studies have found that most cases of ACS arise from defects in signaling molecules associated with the endothelin signaling pathway. Disruption of this signaling pathway in both mouse and zebrafish results in loss of identity of neural crest cells of the mandibular portion of the first pharyngeal arch and the subsequent repatterning of these cells, leading to homeosis of lower jaw structures into more maxillary-like structures. These findings illustrate the importance of endothelin signaling in normal human craniofacial development and illustrate how clinical and basic science approaches can coalesce to improve our understanding of the genetic basis of human birth syndromes. Further, understanding the genetic basis for ACS that lies outside of known endothelin signaling components may help elucidate unknown aspects critical to the establishment of neural crest cell patterning during facial morphogenesis. PMID:24123988

Meningeal defects alter the tangential migration of cortical interneurons in Foxc1hith/hith mice

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Zarbalis Konstantinos

2012-01-01

Full Text Available Abstract Background Tangential migration presents the primary mode of migration of cortical interneurons translocating into the cerebral cortex from subpallial domains. This migration takes place in multiple streams with the most superficial one located in the cortical marginal zone. While a number of forebrain-expressed molecules regulating this process have emerged, it remains unclear to what extent structures outside the brain, like the forebrain meninges, are involved. Results We studied a unique Foxc1 hypomorph mouse model (Foxc1hith/hith with meningeal defects and impaired tangential migration of cortical interneurons. We identified a territorial correlation between meningeal defects and disruption of interneuron migration along the adjacent marginal zone in these animals, suggesting that impaired meningeal integrity might be the primary cause for the observed migration defects. Moreover, we postulate that the meningeal factor regulating tangential migration that is affected in homozygote mutants is the chemokine Cxcl12. In addition, by using chromatin immunoprecipitation analysis, we provide evidence that the Cxcl12 gene is a direct transcriptional target of Foxc1 in the meninges. Further, we observe migration defects of a lesser degree in Cajal-Retzius cells migrating within the cortical marginal zone, indicating a less important role for Cxcl12 in their migration. Finally, the developmental migration defects observed in Foxc1hith/hith mutants do not lead to obvious differences in interneuron distribution in the adult if compared to control animals. Conclusions Our results suggest a critical role for the forebrain meninges to promote during development the tangential migration of cortical interneurons along the cortical marginal zone and Cxcl12 as the factor responsible for this property.

Fibrous metaphyseal defects

International Nuclear Information System (INIS)

Ritschl, P.; Hajek, P.C.; Pechmann, U.

1989-01-01

Sixteen patients with fibrous metaphyseal defects were examined with both plain radiography and magnetic resonance (MR) imaging. Depending on the age of the fibrous metaphyseal defects, characteristic radiomorphologic changes were found which correlated well with MR images. Following intravenous Gadolinium-DTPA injection, fibrous metaphyseal defects invariably exhibited a hyperintense border and signal enhancement. (orig./GDG)

Mouse adhalin

DEFF Research Database (Denmark)

Liu, L; Vachon, P H; Kuang, W

1997-01-01

. To analyze the biological roles of adhalin, we cloned the mouse adhalin cDNA, raised peptide-specific antibodies to its cytoplasmic domain, and examined its expression and localization in vivo and in vitro. The mouse adhalin sequence was 80% identical to that of human, rabbit, and hamster. Adhalin...... was specifically expressed in striated muscle cells and their immediate precursors, and absent in many other cell types. Adhalin expression in embryonic mouse muscle was coincident with primary myogenesis. Its expression was found to be up-regulated at mRNA and protein levels during myogenic differentiation...

Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence: two case reports and a review of the literature.

Science.gov (United States)

Bjørsum-Meyer, Thomas; Herlin, Morten; Qvist, Niels; Petersen, Michael B

2016-12-21

The vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome are rare conditions. We aimed to present two cases with the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser co-occurrence from our local surgical center and through a systematic literature search detect published cases. Furthermore, we aimed to collect existing knowledge in the embryopathogenesis and genetics in order to discuss a possible link between the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome. Our first case was a white girl delivered by caesarean section at 37 weeks of gestation; our second case was a white girl born at a gestational age of 40 weeks. A co-occurrence of vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome was diagnosed in both cases. We performed a systematic literature search in PubMed ((VACTERL) OR (VATER)) AND ((MRKH) OR (Mayer-Rokitansky-Küster-Hauser) OR (mullerian agenesis) OR (mullerian aplasia) OR (MURCS)) without limitations. A similar search was performed in Embase and the Cochrane library. We added two cases from our local center. All cases (n = 9) presented with anal atresia and renal defect. Vertebral defects were present in eight patients. Rectovestibular fistula was confirmed in seven patients. Along with the uterovaginal agenesis, fallopian tube aplasia appeared in five of nine cases and in two cases ovarian involvement also existed. The co-occurrence of the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal

A Copolymer Scaffold Functionalized with Nanodiamond Particles Enhances Osteogenic Metabolic Activity and Bone Regeneration.

Science.gov (United States)

Yassin, Mohammed A; Mustafa, Kamal; Xing, Zhe; Sun, Yang; Fasmer, Kristine Eldevik; Waag, Thilo; Krueger, Anke; Steinmüller-Nethl, Doris; Finne-Wistrand, Anna; Leknes, Knut N

2017-06-01

Functionalizing polymer scaffolds with nanodiamond particles (nDPs) has pronounced effect on the surface properties, such as improved wettability, an increased active area and binding sites for cellular attachment and adhesion, and increased ability to immobilize biomolecules by physical adsorption. This study aims to evaluate the effect of poly(l-lactide-co-ε-caprolactone) (poly(LLA-co-CL)) scaffolds, functionalized with nDPs, on bone regeneration in a rat calvarial critical size defect. Poly(LLA-co-CL) scaffolds functionalized with nDPs are also compared with pristine scaffolds with reference to albumin adsorption and seeding efficiency of bone marrow stromal cells (BMSCs). Compared with pristine scaffolds, the experimental scaffolds exhibit a reduction in albumin adsorption and a significant increase in the seeding efficiency of BMSCs (p = 0.027). In the calvarial defects implanted with BMSC-seeded poly(LLA-co-CL)/nDPs scaffolds, live imaging at 12 weeks discloses a significant increase in osteogenic metabolic activity (p = 0.016). Microcomputed tomography, confirmed by histological data, reveals a substantial increase in bone volume (p = 0.021). The results show that compared with conventional poly(LLA-co-CL) scaffolds those functionalized with nDPs promote osteogenic metabolic activity and mineralization capacity. It is concluded that poly(LLA-co-CL) composite matrices functionalized with nDPs enhance osteoconductivity and therefore warrant further study as potential scaffolding material for bone tissue engineering. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Efficacy of rhBMP-2 Loaded PCL/β-TCP/bdECM Scaffold Fabricated by 3D Printing Technology on Bone Regeneration

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Eun-Bin Bae

2018-01-01

Full Text Available This study was undertaken to evaluate the effect of 3D printed polycaprolactone (PCL/β-tricalcium phosphate (β-TCP scaffold containing bone demineralized and decellularized extracellular matrix (bdECM and human recombinant bone morphogenetic protein-2 (rhBMP-2 on bone regeneration. Scaffolds were divided into PCL/β-TCP, PCL/β-TCP/bdECM, and PCL/β-TCP/bdECM/BMP groups. In vitro release kinetics of rhBMP-2 were determined with respect to cell proliferation and osteogenic differentiation. These three reconstructive materials were implanted into 8 mm diameter calvarial bone defect in male Sprague-Dawley rats. Animals were sacrificed four weeks after implantation for micro-CT, histologic, and histomorphometric analyses. The findings obtained were used to calculate new bone volumes (mm3 and new bone areas (%. Excellent cell bioactivity was observed in the PCL/β-TCP/bdECM and PCL/β-TCP/bdECM/BMP groups, and new bone volume and area were significantly higher in the PCL/β-TCP/bdECM/BMP group than in the other groups (p<.05. Within the limitations of this study, bdECM printed PCL/β-TCP scaffolds can reproduce microenvironment for cells and promote adhering and proliferating the cells onto scaffolds. Furthermore, in the rat calvarial defect model, the scaffold which printed rhBMP-2 loaded bdECM stably carries rhBMP-2 and enhances bone regeneration confirming the possibility of bdECM as rhBMP-2 carrier.

ILT based defect simulation of inspection images accurately predicts mask defect printability on wafer

Science.gov (United States)

Deep, Prakash; Paninjath, Sankaranarayanan; Pereira, Mark; Buck, Peter

2016-05-01

At advanced technology nodes mask complexity has been increased because of large-scale use of resolution enhancement technologies (RET) which includes Optical Proximity Correction (OPC), Inverse Lithography Technology (ILT) and Source Mask Optimization (SMO). The number of defects detected during inspection of such mask increased drastically and differentiation of critical and non-critical defects are more challenging, complex and time consuming. Because of significant defectivity of EUVL masks and non-availability of actinic inspection, it is important and also challenging to predict the criticality of defects for printability on wafer. This is one of the significant barriers for the adoption of EUVL for semiconductor manufacturing. Techniques to decide criticality of defects from images captured using non actinic inspection images is desired till actinic inspection is not available. High resolution inspection of photomask images detects many defects which are used for process and mask qualification. Repairing all defects is not practical and probably not required, however it's imperative to know which defects are severe enough to impact wafer before repair. Additionally, wafer printability check is always desired after repairing a defect. AIMSTM review is the industry standard for this, however doing AIMSTM review for all defects is expensive and very time consuming. Fast, accurate and an economical mechanism is desired which can predict defect printability on wafer accurately and quickly from images captured using high resolution inspection machine. Predicting defect printability from such images is challenging due to the fact that the high resolution images do not correlate with actual mask contours. The challenge is increased due to use of different optical condition during inspection other than actual scanner condition, and defects found in such images do not have correlation with actual impact on wafer. Our automated defect simulation tool predicts

Genetic mouse models of brain ageing and Alzheimer's disease.

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Bilkei-Gorzo, Andras

2014-05-01

Progression of brain ageing is influenced by a complex interaction of genetic and environmental factors. Analysis of genetically modified animals with uniform genetic backgrounds in a standardised, controlled environment enables the dissection of critical determinants of brain ageing on a molecular level. Human and animal studies suggest that increased load of damaged macromolecules, efficacy of DNA maintenance, mitochondrial activity, and cellular stress defences are critical determinants of brain ageing. Surprisingly, mouse lines with genetic impairment of anti-oxidative capacity generally did not show enhanced cognitive ageing but rather an increased sensitivity to oxidative challenge. Mouse lines with impaired mitochondrial activity had critically short life spans or severe and rapidly progressing neurodegeneration. Strains with impaired clearance in damaged macromolecules or defects in the regulation of cellular stress defences showed alterations in the onset and progression of cognitive decline. Importantly, reduced insulin/insulin-like growth factor signalling generally increased life span but impaired cognitive functions revealing a complex interaction between ageing of the brain and of the body. Brain ageing is accompanied by an increased risk of developing Alzheimer's disease. Transgenic mouse models expressing high levels of mutant human amyloid precursor protein showed a number of symptoms and pathophysiological processes typical for early phase of Alzheimer's disease. Generally, therapeutic strategies effective against Alzheimer's disease in humans were also active in the Tg2576, APP23, APP/PS1 and 5xFAD lines, but a large number of false positive findings were also reported. The 3xtg AD model likely has the highest face and construct validity but further studies are needed. Copyright © 2013 Elsevier Inc. All rights reserved.

Defect detection based on extreme edge of defective region histogram

Directory of Open Access Journals (Sweden)

Zouhir Wakaf

2018-01-01

Full Text Available Automatic thresholding has been used by many applications in image processing and pattern recognition systems. Specific attention was given during inspection for quality control purposes in various industries like steel processing and textile manufacturing. Automatic thresholding problem has been addressed well by the commonly used Otsu method, which provides suitable results for thresholding images based on a histogram of bimodal distribution. However, the Otsu method fails when the histogram is unimodal or close to unimodal. Defects have different shapes and sizes, ranging from very small to large. The gray-level distributions of the image histogram can vary between unimodal and multimodal. Furthermore, Otsu-revised methods, like the valley-emphasis method and the background histogram mode extents, which overcome the drawbacks of the Otsu method, require preprocessing steps and fail to use the general threshold for multimodal defects. This study proposes a new automatic thresholding algorithm based on the acquisition of the defective region histogram and the selection of its extreme edge as the threshold value to segment all defective objects in the foreground from the image background. To evaluate the proposed defect-detection method, common standard images for experimentation were used. Experimental results of the proposed method show that the proposed method outperforms the current methods in terms of defect detection.

S1 nuclease analysis of α-globin gene expression in preleukemic patients with acquired hemoglobin H disease after transfer to mouse erythroleukemia cells

International Nuclear Information System (INIS)

Helder, J.; Deisseroth, A.

1987-01-01

The loss of α-globin gene transcriptional activity rarely occurs as an acquired abnormality during the evolution of myeloproliferative disease or preleukemia. To test whether the mutation responsible for the loss of α-globin gene expression (hemoglobin H disease) in these patients is linked with the α-globin genes on chromosome 16, the authors transferred chromosome 16 from preleukemic patients with acquired hemoglobin H disease to mouse erythroleukemia cells and measured the transcriptional activity of the human α-globin genes. After transfer to mouse erythroleukemia cells, the expression of human α-globin genes from the peripheral blood or marrow cells of preleukemic patients with acquired hemoglobin H disease was similar to that of human α-globin genes transferred to mouse erythroleukemia cells from normal donors. These data showed that factor(s) in the mouse erythroleukemia cell can genetically complement the α-globin gene defect in these preleukemia patients with acquired hemoglobin H disease and suggest that altered expression of a gene in trans to the α-globin gene may be responsible for the acquisition of hemoglobin H disease in these patients

Synthetic Defects for Vibrothermography

Science.gov (United States)

Renshaw, Jeremy; Holland, Stephen D.; Thompson, R. Bruce; Eisenmann, David J.

2010-02-01

Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane.

Mitochondrial DNA mutations in mutator mice confer respiration defects and B-cell lymphoma development.

Directory of Open Access Journals (Sweden)

Takayuki Mito

Full Text Available Mitochondrial DNA (mtDNA mutator mice are proposed to express premature aging phenotypes including kyphosis and hair loss (alopecia due to their carrying a nuclear-encoded mtDNA polymerase with a defective proofreading function, which causes accelerated accumulation of random mutations in mtDNA, resulting in expression of respiration defects. On the contrary, transmitochondrial mito-miceΔ carrying mtDNA with a large-scale deletion mutation (ΔmtDNA also express respiration defects, but not express premature aging phenotypes. Here, we resolved this discrepancy by generating mtDNA mutator mice sharing the same C57BL/6J (B6J nuclear background with that of mito-miceΔ. Expression patterns of premature aging phenotypes are very close, when we compared between homozygous mtDNA mutator mice carrying a B6J nuclear background and selected mito-miceΔ only carrying predominant amounts of ΔmtDNA, in their expression of significant respiration defects, kyphosis, and a short lifespan, but not the alopecia. Therefore, the apparent discrepancy in the presence and absence of premature aging phenotypes in mtDNA mutator mice and mito-miceΔ, respectively, is partly the result of differences in the nuclear background of mtDNA mutator mice and of the broad range of ΔmtDNA proportions of mito-miceΔ used in previous studies. We also provided direct evidence that mtDNA abnormalities in homozygous mtDNA mutator mice are responsible for respiration defects by demonstrating the co-transfer of mtDNA and respiration defects from mtDNA mutator mice into mtDNA-less (ρ(0 mouse cells. Moreover, heterozygous mtDNA mutator mice had a normal lifespan, but frequently developed B-cell lymphoma, suggesting that the mtDNA abnormalities in heterozygous mutator mice are not sufficient to induce a short lifespan and aging phenotypes, but are able to contribute to the B-cell lymphoma development during their prolonged lifespan.

The effect of DNA repair defects on reproductive performance in nucleotide excision repair (NER) mouse models: an epidemiological approach

NARCIS (Netherlands)

Tsai, P.S.; Nielen, M.; Horst, G.T.J. van der; Colenbrander, B.; Heesterbeek, J.A.P.; Fentener van Vlissingen, J.M.

2005-01-01

In this study, we used an epidemiological approach to analyze an animal database of DNA repair deficient mice on reproductive performance in five Nucleotide Excision Repair (NER) mutant mouse models on a C57BL/6 genetic background, namely CSA, CSB, XPA, XPC [models for the human DNA repair disorders

Analysis of the presence of cell proliferation-related molecules in the Tgf-β3 null mutant mouse palate reveals misexpression of EGF and Msx-1.

Science.gov (United States)

del Río, A; Barrio, M C; Murillo, J; Maldonado, E; López-Gordillo, Y; Martínez-Sanz, E; Martínez, M L; Martínez-Álvarez, C

2011-01-01

The Tgf-β(3) null mutant mouse palate presents several cellular anomalies that lead to the appearance of cleft palate. One of them concerns the cell proliferation of both the palatal medial edge epithelium and mesenchyme. In this work, our aim was to determine whether there was any variation in the presence/distribution of several cell proliferation-related molecules that could be responsible for the cell proliferation defects observed in these palates. Our results showed no difference in the presence of EGF-R, PDGF-A, TGF-β(2), Bmp-2, and Bmp-4, and differences were minimal for FGF-10 and Shh. However, the expression of EGF and Msx-1 changed substantially. The shift of the EGF protein expression was the one that most correlated with that of cell proliferation. This molecule is regulated by TGF-β(3), and experiments blocking its activity in culture suggest that EGF misexpression in the Tgf-β(3) null mutant mouse palate plays a role in the cell proliferation defect observed. Copyright © 2010 S. Karger AG, Basel.

Formate supplementation enhances folate-dependent nucleotide biosynthesis and prevents spina bifida in a mouse model of folic acid-resistant neural tube defects.

Science.gov (United States)

Sudiwala, Sonia; De Castro, Sandra C P; Leung, Kit-Yi; Brosnan, John T; Brosnan, Margaret E; Mills, Kevin; Copp, Andrew J; Greene, Nicholas D E

2016-07-01

The curly tail mouse provides a model for neural tube defects (spina bifida and exencephaly) that are resistant to prevention by folic acid. The major ct gene, responsible for spina bifida, corresponds to a hypomorphic allele of grainyhead-like 3 (Grhl3) but the frequency of NTDs is strongly influenced by modifiers in the genetic background. Moreover, exencephaly in the curly tail strain is not prevented by reinstatement of Grhl3 expression. In the current study we found that expression of Mthfd1L, encoding a key component of mitochondrial folate one-carbon metabolism (FOCM), is significantly reduced in ct/ct embryos compared to a partially congenic wild-type strain. This expression change is not attributable to regulation by Grhl3 or the genetic background at the Mthfd1L locus. Mitochondrial FOCM provides one-carbon units as formate for FOCM reactions in the cytosol. We found that maternal supplementation with formate prevented NTDs in curly tail embryos and also resulted in increased litter size. Analysis of the folate profile of neurulation-stage embryos showed that formate supplementation resulted in an increased proportion of formyl-THF and THF but a reduction in proportion of 5-methyl THF. In contrast, THF decreased and 5-methyl THF was relatively more abundant in the liver of supplemented dams than in controls. In embryos cultured through the period of spinal neurulation, incorporation of labelled thymidine and adenine into genomic DNA was suppressed by supplemental formate, suggesting that de novo folate-dependent biosynthesis of nucleotides (thymidylate and purines) was enhanced. We hypothesise that reduced Mthfd1L expression may contribute to susceptibility to NTDs in the curly tail strain and that formate acts as a one-carbon donor to prevent NTDs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Smc1β is required for activation of SAC during mouse oocyte meiosis.

Science.gov (United States)

Miao, Yilong; Zhou, Changyin; Cui, Zhaokang; Dai, Xiaoxin; Zhang, Mianqun; Lu, Yajuan; Xiong, Bo

2017-03-19

Smc1β is a meiosis-specific cohesin subunit that is essential for sister chromatid cohesion and DNA recombination. Previous studies have shown that Smc1β-deficient mice in both sexes are sterile. Ablation of Smc1β during male meiosis leads to the blockage of spermatogenesis in pachytene stage, and ablation of Smc1β during female meiosis generates a highly error-prone oocyte although it could develop to metaphase II stage. However, the underlying mechanisms regarding how Smc1β maintains the correct meiotic progression in mouse oocytes have not been clearly defined. Here, we find that GFP-fused Smc1β is expressed and localized to the chromosomes from GV to MII stages during mouse oocyte meiotic maturation. Knockdown of Smc1β by microinjection of gene-specific morpholino causes the impaired spindle apparatus and chromosome alignment which are highly correlated with the defective kinetochore-microtubule attachments, consequently resulting in a prominently higher incidence of aneuploid eggs. In addition, the premature extrusion of polar bodies and escape of metaphase I arrest induced by low dose of nocodazole treatment in Smc1β-depleted oocytes indicates that Smc1β is essential for activation of spindle assembly checkpoint (SAC) activity. Collectively, we identify a novel function of Smc1β as a SAC participant beyond its role in chromosome cohesion during mouse oocyte meiosis.

Defining ATM-Independent Functions of the Mre11 Complex with a Novel Mouse Model.

Science.gov (United States)

Balestrini, Alessia; Nicolas, Laura; Yang-Lott, Katherine; Guryanova, Olga A; Levine, Ross L; Bassing, Craig H; Chaudhuri, Jayanta; Petrini, John H J

2016-02-01

The Mre11 complex (Mre11, Rad50, and Nbs1) occupies a central node of the DNA damage response (DDR) network and is required for ATM activation in response to DNA damage. Hypomorphic alleles of MRE11 and NBS1 confer embryonic lethality in ATM-deficient mice, indicating that the complex exerts ATM-independent functions that are essential when ATM is absent. To delineate those functions, a conditional ATM allele (ATM(flox)) was crossed to hypomorphic NBS1 mutants (Nbs1(ΔB/ΔB) mice). Nbs1(ΔB/ΔB) Atm(-/-) hematopoietic cells derived by crossing to vav(cre) were viable in vivo. Nbs1(ΔB/ΔB) Atm(-/-) (VAV) mice exhibited a pronounced defect in double-strand break repair and completely penetrant early onset lymphomagenesis. In addition to repair defects observed, fragile site instability was noted, indicating that the Mre11 complex promotes genome stability upon replication stress in vivo. The data suggest combined influences of the Mre11 complex on DNA repair, as well as the responses to DNA damage and DNA replication stress. A novel mouse model was developed, by combining a vav(cre)-inducible ATM knockout mouse with an NBS1 hypomorphic mutation, to analyze ATM-independent functions of the Mre11 complex in vivo. These data show that the DNA repair, rather than DDR signaling functions of the complex, is acutely required in the context of ATM deficiency to suppress genome instability and lymphomagenesis. ©2015 American Association for Cancer Research.

Maternal SENP7 programs meiosis architecture and embryo survival in mouse.

Science.gov (United States)

Huang, Chun-Jie; Wu, Di; Jiao, Xiao-Fei; Khan, Faheem Ahmed; Xiong, Cheng-Liang; Liu, Xiao-Ming; Yang, Jing; Yin, Tai-Lang; Huo, Li-Jun

2017-07-01

Understanding the mechanisms underlying abnormal egg production and pregnancy loss is significant for human fertility. SENP7, a SUMO poly-chain editing enzyme, has been regarded as a mitotic regulator of heterochromatin integrity and DNA repair. Herein, we report the roles of SENP7 in mammalian reproductive scenario. Mouse oocytes deficient in SENP7 experienced meiotic arrest at prophase I and metaphase I stages, causing a substantial decrease of mature eggs. Hyperaceylation and hypomethylation of histone H3 and up-regulation of Cdc14B/C accompanied by down-regulation of CyclinB1 and CyclinB2 were further recognized as contributors to defective M-phase entry and spindle assembly in oocytes. The spindle assembly checkpoint activated by defective spindle morphogenesis, which was also caused by mislocalization and ubiquitylation-mediated proteasomal degradation of γ-tubulin, blocked oocytes at meiosis I stage. SENP7-depleted embryos exhibited severely defective maternal-zygotic transition and progressive degeneration, resulting in nearly no blastocyst production. The disrupted epigenetic landscape on histone H3 restricted Rad51C loading onto DNA lesions due to elevated HP1α euchromatic deposition, and reduced DNA 5hmC challenged the permissive status for zygotic DNA repair, which induce embryo death. Our study pinpoints SENP7 as a novel determinant in epigenetic programming and major pathways that govern oocyte and embryo development programs in mammals. Copyright © 2017 Elsevier B.V. All rights reserved.

Facts about Birth Defects

Science.gov (United States)

... label> Information For… Media Policy Makers Facts about Birth Defects Language: English (US) Español (Spanish) Recommend on ... having a baby born without a birth defect. Birth Defects Are Common Every 4 ½ minutes, a ...

Retinoblastoma pathway defects show differential ability to activate the constitutive DNA damage response in human tumorigenesis

DEFF Research Database (Denmark)

Tort, F.; Bartkova, J.; Sehested, M.

2006-01-01

culture models with differential defects of retinoblastoma pathway components, as overexpression of cyclin D1 or lack of p16(Ink4a), either alone or combined, did not elicit detectable DDR. In contrast, inactivation of pRb, the key component of the pathway, activated the DDR in cultured human or mouse...... with their hierarchical positions along the retinoblastoma pathway. Our data provide new insights into oncogene-evoked DDR in human tumorigenesis, with potential implications for individualized management of tumors with elevated cyclin D1 versus cyclin E, due to their distinct clinical variables and biological behavior....

Localized irradiation of mouse legs using an image-guided robotic linear accelerator.

Science.gov (United States)

Kufeld, Markus; Escobar, Helena; Marg, Andreas; Pasemann, Diana; Budach, Volker; Spuler, Simone

2017-04-01

To investigate the potential of human satellite cells in muscle regeneration small animal models are useful to evaluate muscle regeneration. To suppress the inherent regeneration ability of the tibialis muscle of mice before transplantation of human muscle fibers, a localized irradiation of the mouse leg should be conducted. We analyzed the feasibility of an image-guided robotic irradiation procedure, a routine treatment method in radiation oncology, for the focal irradiation of mouse legs. After conducting a planning computed tomography (CT) scan of one mouse in its customized mold a three-dimensional dose plan was calculated using a dedicated planning workstation. 18 Gy have been applied to the right anterior tibial muscle of 4 healthy and 12 mice with immune defect in general anesthesia using an image-guided robotic linear accelerator (LINAC). The mice were fixed in a customized acrylic mold with attached fiducial markers for image guided tracking. All 16 mice could be irradiated as prevised without signs of acute radiation toxicity or anesthesiological side effects. The animals survived until scarification after 8, 21 and 49 days as planned. The procedure was straight forward and the irradiation process took 5 minutes to apply the dose of 18 Gy. Localized irradiation of mice legs using a robotic LINAC could be conducted as planned. It is a feasible procedure without recognizable side effects. Image guidance offers precise dose delivery and preserves adjacent body parts and tissues.

Trigonellae Semen Enhances Sperm Motility and the Expression of the Cation Sperm Channel Proteins in Mouse Testes

Directory of Open Access Journals (Sweden)

Do Rim Kim

2015-01-01

Full Text Available Genetic defects during spermatogenesis can lead to a reduction in sperm motility and cause male infertility. The cation channels of sperm (CatSper play a role in the regulation of hyperactivated sperm motility in mouse testes. The effect of Trigonellae Semen (TS on the male reproductive system and CatSper protein in mouse testes during spermatogenesis was examined. C57BL/c mice were divided into the following five groups: normal, cyclophosphamide- (CP- only treated (control group, and three groups treated with varying concentrations of TS with CP (100, 500, and 1000 mg/kg TS and 100 mg/kg CP. Real-time PCR, western blot analysis, and a testosterone immunoassay were performed to assess CatSper protein levels in the five groups. Additionally, sperm cell counts and motility were examined. Results indicate that sperm motility and sperm counts increased in the TS treated groups in a dose-dependent manner (p<0.01. CatSper levels were also significantly higher in the TS treated groups compared to that of the control group (p<0.001. Therefore, TS treatment could enhance sperm function by promoting spermatogenesis and the expression of CatSper proteins in mouse testes.

Defect production in ceramics

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J. [Oak Ridge National Lab., TN (United States); Kinoshita, C. [Kyushu Univ. (Japan)

1997-08-01

A review is given of several important defect production and accumulation parameters for irradiated ceramics. Materials covered in this review include alumina, magnesia, spinel silicon carbide, silicon nitride, aluminum nitride and diamond. Whereas threshold displacement energies for many ceramics are known within a reasonable level of uncertainty (with notable exceptions being AIN and Si{sub 3}N{sub 4}), relatively little information exists on the equally important parameters of surviving defect fraction (defect production efficiency) and point defect migration energies for most ceramics. Very little fundamental displacement damage information is available for nitride ceramics. The role of subthreshold irradiation on defect migration and microstructural evolution is also briefly discussed.

Defects in dilute nitrides

International Nuclear Information System (INIS)

Chen, W.M.; Buyanova, I.A.; Tu, C.W.; Yonezu, H.

2005-01-01

We provide a brief review our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in dilute nitrides, i.e. Ga(In)NAs and Ga(Al,In)NP. Defect complexes involving intrinsic defects such as As Ga antisites and Ga i self interstitials were positively identified.Effects of growth conditions, chemical compositions and post-growth treatments on formation of the defects are closely examined. These grown-in defects are shown to play an important role in non-radiative carrier recombination and thus in degrading optical quality of the alloys, harmful to performance of potential optoelectronic and photonic devices based on these dilute nitrides. (author)

Genital and Urinary Tract Defects

Science.gov (United States)

... conditions > Genital and urinary tract defects Genital and urinary tract defects E-mail to a friend Please fill ... and extra fluids. What problems can genital and urinary tract defects cause? Genital and urinary tract defects affect ...

Expression of Caytaxin protein in Cayman Ataxia mouse models correlates with phenotype severity.

Directory of Open Access Journals (Sweden)

Kristine M Sikora

Full Text Available Caytaxin is a highly-conserved protein, which is encoded by the Atcay/ATCAY gene. Mutations in Atcay/ATCAY have been identified as causative of cerebellar disorders such as the rare hereditary disease Cayman ataxia in humans, generalized dystonia in the dystonic (dt rat, and marked motor defects in three ataxic mouse lines. While several lines of evidence suggest that Caytaxin plays a critical role in maintaining nervous system processes, the physiological function of Caytaxin has not been fully characterized. In the study presented here, we generated novel specific monoclonal antibodies against full-length Caytaxin to examine endogenous Caytaxin expression in wild type and Atcay mutant mouse lines. Caytaxin protein is absent from brain tissues in the two severely ataxic Atcay(jit (jittery and Atcay(swd (sidewinder mutant lines, and markedly decreased in the mildly ataxic/dystonic Atcay(ji-hes (hesitant line, indicating a correlation between Caytaxin expression and disease severity. As the expression of wild type human Caytaxin in mutant sidewinder and jittery mice rescues the ataxic phenotype, Caytaxin's physiological function appears to be conserved between the human and mouse orthologs. Across multiple species and in several neuronal cell lines Caytaxin is expressed as several protein isoforms, the two largest of which are caused by the usage of conserved methionine translation start sites. The work described in this manuscript presents an initial characterization of the Caytaxin protein and its expression in wild type and several mutant mouse models. Utilizing these animal models of human Cayman Ataxia will now allow an in-depth analysis to elucidate Caytaxin's role in maintaining normal neuronal function.

Point defects and defect clusters examined on the basis of some fundamental experiments

International Nuclear Information System (INIS)

Zuppiroli, L.

1975-01-01

On progressing from the centre of the defect to the surface the theoretical approach to a point defect passes from electronic theories to elastic theory. Experiments by which the point defect can be observed fall into two categories. Those which detect long-range effects: measurement of dimensional variations in the sample; measurement of the mean crystal parameter variation; elastic X-ray scattering near the nodes of the reciprocal lattice (Huang scattering). Those which detect more local effects: low-temperature resistivity measurement; positron capture and annihilation; local scattering far from the reciprocal lattice nodes. Experiments involving both short and long-range effects can always be found. This is the case for example with the dechanneling of α particles by defects. Certain of the experimental methods quoted above apply also to the study of point defect clusters. These methods are illustrated by some of their most striking results which over the last twenty years have refined our knowledge of point defects and defect clusters: length and crystal parameter measurements; diffuse X-ray scattering; low-temperature resistivity measurements; ion emission microscopy; electron microscopy; elastoresistivity [fr

Birth Defects (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Birth Defects KidsHealth / For Parents / Birth Defects What's in ... Prevented? Print en español Anomalías congénitas What Are Birth Defects? While still in the womb, some babies ...

Defect of the Eyelids.

Science.gov (United States)

Lu, Guanning Nina; Pelton, Ron W; Humphrey, Clinton D; Kriet, John David

2017-08-01

Eyelid defects disrupt the complex natural form and function of the eyelids and present a surgical challenge. Detailed knowledge of eyelid anatomy is essential in evaluating a defect and composing a reconstructive plan. Numerous reconstructive techniques have been described, including primary closure, grafting, and a variety of local flaps. This article describes an updated reconstructive ladder for eyelid defects that can be used in various permutations to solve most eyelid defects. Copyright © 2017 Elsevier Inc. All rights reserved.

A mutation in the tuft mouse disrupts TET1 activity and alters the expression of genes that are crucial for neural tube closure

Directory of Open Access Journals (Sweden)

Keith S. K. Fong

2016-05-01

Full Text Available Genetic variations affecting neural tube closure along the head result in malformations of the face and brain. Neural tube defects (NTDs are among the most common birth defects in humans. We previously reported a mouse mutant called tuft that arose spontaneously in our wild-type 3H1 colony. Adult tuft mice present midline craniofacial malformations with or without an anterior cephalocele. In addition, affected embryos presented neural tube closure defects resulting in insufficient closure of the anterior neuropore or exencephaly. Here, through whole-genome sequencing, we identified a nonsense mutation in the Tet1 gene, which encodes a methylcytosine dioxygenase (TET1, co-segregating with the tuft phenotype. This mutation resulted in premature termination that disrupts the catalytic domain that is involved in the demethylation of cytosine. We detected a significant loss of TET enzyme activity in the heads of tuft embryos that were homozygous for the mutation and had NTDs. RNA-Seq transcriptome analysis indicated that multiple gene pathways associated with neural tube closure were dysregulated in tuft embryo heads. Among them, the expressions of Cecr2, Epha7 and Grhl2 were significantly reduced in some embryos presenting neural tube closure defects, whereas one or more components of the non-canonical WNT signaling pathway mediating planar cell polarity and convergent extension were affected in others. We further show that the recombinant mutant TET1 protein was capable of entering the nucleus and affected the expression of endogenous Grhl2 in IMCD-3 (inner medullary collecting duct cells. These results indicate that TET1 is an epigenetic determinant for regulating genes that are crucial to closure of the anterior neural tube and its mutation has implications to craniofacial development, as presented by the tuft mouse.

Effects of In Utero Thyroxine Exposure on Murine Cranial Suture Growth.

Directory of Open Access Journals (Sweden)

R Nicole Howie

Full Text Available Large scale surveillance studies, case studies, as well as cohort studies have identified the influence of thyroid hormones on calvarial growth and development. Surveillance data suggests maternal thyroid disorders (hyperthyroidism, hypothyroidism with pharmacological replacement, and Maternal Graves Disease are linked to as much as a 2.5 fold increased risk for craniosynostosis. Craniosynostosis is the premature fusion of one or more calvarial growth sites (sutures prior to the completion of brain expansion. Thyroid hormones maintain proper bone mineral densities by interacting with growth hormone and aiding in the regulation of insulin like growth factors (IGFs. Disruption of this hormonal control of bone physiology may lead to altered bone dynamics thereby increasing the risk for craniosynostosis. In order to elucidate the effect of exogenous thyroxine exposure on cranial suture growth and morphology, wild type C57BL6 mouse litters were exposed to thyroxine in utero (control = no treatment; low ~167 ng per day; high ~667 ng per day. Thyroxine exposed mice demonstrated craniofacial dysmorphology (brachycranic. High dose exposed mice showed diminished area of the coronal and widening of the sagittal sutures indicative of premature fusion and compensatory growth. Presence of thyroid receptors was confirmed for the murine cranial suture and markers of proliferation and osteogenesis were increased in sutures from exposed mice. Increased Htra1 and Igf1 gene expression were found in sutures from high dose exposed individuals. Pathways related to the HTRA1/IGF axis, specifically Akt and Wnt, demonstrated evidence of increased activity. Overall our data suggest that maternal exogenous thyroxine exposure can drive calvarial growth alterations and altered suture morphology.

Effects of In Utero Thyroxine Exposure on Murine Cranial Suture Growth.

Science.gov (United States)

Howie, R Nicole; Durham, Emily L; Black, Laurel; Bennfors, Grace; Parsons, Trish E; Elsalanty, Mohammed E; Yu, Jack C; Weinberg, Seth M; Cray, James J

2016-01-01

Large scale surveillance studies, case studies, as well as cohort studies have identified the influence of thyroid hormones on calvarial growth and development. Surveillance data suggests maternal thyroid disorders (hyperthyroidism, hypothyroidism with pharmacological replacement, and Maternal Graves Disease) are linked to as much as a 2.5 fold increased risk for craniosynostosis. Craniosynostosis is the premature fusion of one or more calvarial growth sites (sutures) prior to the completion of brain expansion. Thyroid hormones maintain proper bone mineral densities by interacting with growth hormone and aiding in the regulation of insulin like growth factors (IGFs). Disruption of this hormonal control of bone physiology may lead to altered bone dynamics thereby increasing the risk for craniosynostosis. In order to elucidate the effect of exogenous thyroxine exposure on cranial suture growth and morphology, wild type C57BL6 mouse litters were exposed to thyroxine in utero (control = no treatment; low ~167 ng per day; high ~667 ng per day). Thyroxine exposed mice demonstrated craniofacial dysmorphology (brachycranic). High dose exposed mice showed diminished area of the coronal and widening of the sagittal sutures indicative of premature fusion and compensatory growth. Presence of thyroid receptors was confirmed for the murine cranial suture and markers of proliferation and osteogenesis were increased in sutures from exposed mice. Increased Htra1 and Igf1 gene expression were found in sutures from high dose exposed individuals. Pathways related to the HTRA1/IGF axis, specifically Akt and Wnt, demonstrated evidence of increased activity. Overall our data suggest that maternal exogenous thyroxine exposure can drive calvarial growth alterations and altered suture morphology.

Formation of topological defects

International Nuclear Information System (INIS)

Vachaspati, T.

1991-01-01

We consider the formation of point and line topological defects (monopoles and strings) from a general point of view by allowing the probability of formation of a defect to vary. To investigate the statistical properties of the defects at formation we give qualitative arguments that are independent of any particular model in which such defects occur. These arguments are substantiated by numerical results in the case of strings and for monopoles in two dimensions. We find that the network of strings at formation undergoes a transition at a certain critical density below which there are no infinite strings and the closed-string (loop) distribution is exponentially suppressed at large lengths. The results are contrasted with the results of statistical arguments applied to a box of strings in dynamical equilibrium. We argue that if point defects were to form with smaller probability, the distance between monopoles and antimonopoles would decrease while the monopole-to-monopole distance would increase. We find that monopoles are always paired with antimonopoles but the pairing becomes clean only when the number density of defects is small. A similar reasoning would also apply to other defects

Photographic guide of selected external defect indicators and associated internal defects in sugar maple

Science.gov (United States)

Everette D. Rast; John A. Beaton; David L. Sonderman

1991-01-01

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for sugar maple. Eleven types of external...

Photographic guide of selected external defect indicators and associated internal defects in yellow-poplar

Science.gov (United States)

Everette D. Rast; John A. Beaton; David L. Sonderman

1991-01-01

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow-poplar. Twelve types of external...

Photographic guide of selected external defect indicators and associated internal defects in yellow birch

Science.gov (United States)

Everette D. Rast; John A. Beaton; David L. Sonderman

1991-01-01

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow birch. Eleven types of external...

Distribution of defects in wind turbine blades and reliability assessment of blades containing defects

DEFF Research Database (Denmark)

Stensgaard Toft, Henrik; Branner, Kim; Berring, Peter

2009-01-01

on the assumption that one error in the production process tends to trigger several defects. For both models additional information about number, type and size of the defects is included as stochastic variables. The probability of failure for a wind turbine blade will not only depend on variations in the material......In the present paper two stochastic models for the distribution of defects in wind turbine blades are proposed. The first model assumes that the individual defects are completely randomly distributed in the blade. The second model assumes that the defects occur in clusters of different size based...... properties and the load but also on potential defects in the blades. As a numerical example the probability of failure is calculated for the main spar both with and without defects in terms of delaminations. The delaminations increase the probability of failure compared to a perfect blade, but by applying...

Low-dose ionizing radiation alleviates Aβ42-induced defective phenotypes in Drosophila Alzheimer's disease models

Energy Technology Data Exchange (ETDEWEB)

Hwang, SooJin; Jeong, Hae Min; Nam, Seon Young [Low-dose Radiation Research Team, Radiation Health Institute, Korea Hydro & Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

2017-04-15

Alzheimer's disease (AD) is the most common neurodegenerative disease that is characterized by amyloid plaques, progressive neuronal loss, and gradual deterioration of memory. Amyloid imaging using positron emission tomography (PET) radiotracers have been developed and approved for clinical use in the evaluation of suspected neurodegenerative disease, including AD. Particularly, previous studies involving low-dose ionizing radiation on Aβ 42-treated mouse hippocampal neurons have suggested a potential role for low-dose ionizing radiation in the treatment of AD. However, associated in vivo studies involving the therapy effects of low-dose ionizing radiation on AD are still insufficient. As a powerful cell biological system, Drosophila AD models have been generated and established a useful model organism for study on the etiology of human AD. In this study, we investigated the hormesis effects of low-dose ionizing radiation on Drosophila AD models. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation. Our results suggest that low-dose ionizing radiation have the beneficial effects on not only the Aβ42-induced developmental defective phenotypes but also motor defects in Drosophila AD models. These results might be due to a regulation of apoptosis, and provide insight into the hormesis effects of low-dose ionizing radiation.

Entanglement entropy in integrable field theories with line defects II. Non-topological defect

Science.gov (United States)

Jiang, Yunfeng

2017-08-01

This is the second part of two papers where we study the effect of integrable line defects on bipartite entanglement entropy in integrable field theories. In this paper, we consider non-topological line defects in Ising field theory. We derive an infinite series expression for the entanglement entropy and show that both the UV and IR limits of the bulk entanglement entropy are modified by the line defect. In the UV limit, we give an infinite series expression for the coefficient in front of the logarithmic divergence and the exact defect g-function. By tuning the defect to be purely transmissive and reflective, we recover correctly the entanglement entropy of the bulk and with integrable boundary respectively.

Adeno-associated virus-mediated rescue of the cognitive defects in a mouse model for Angelman syndrome.

Directory of Open Access Journals (Sweden)

Jennifer L Daily

Full Text Available Angelman syndrome (AS, a genetic disorder occurring in approximately one in every 15,000 births, is characterized by severe mental retardation, seizures, difficulty speaking and ataxia. The gene responsible for AS was discovered to be UBE3A and encodes for E6-AP, an ubiquitin ligase. A unique feature of this gene is that it undergoes maternal imprinting in a neuron-specific manner. In the majority of AS cases, there is a mutation or deletion in the maternally inherited UBE3A gene, although other cases are the result of uniparental disomy or mismethylation of the maternal gene. While most human disorders characterized by severe mental retardation involve abnormalities in brain structure, no gross anatomical changes are associated with AS. However, we have determined that abnormal calcium/calmodulin-dependent protein kinase II (CaMKII regulation is seen in the maternal UBE3A deletion AS mouse model and is responsible for the major phenotypes. Specifically, there is an increased αCaMKII phosphorylation at the autophosphorylation sites Thr(286 and Thr(305/306, resulting in an overall decrease in CaMKII activity. CaMKII is not produced until after birth, indicating that the deficits associated with AS are not the result of developmental abnormalities. The present studies are focused on exploring the potential to rescue the learning and memory deficits in the adult AS mouse model through the use of an adeno-associated virus (AAV vector to increase neuronal UBE3A expression. These studies show that increasing the levels of E6-AP in the brain using an exogenous vector can improve the cognitive deficits associated with AS. Specifically, the associative learning deficit was ameliorated in the treated AS mice compared to the control AS mice, indicating that therapeutic intervention may be possible in older AS patients.

Decreasing maternal myostatin programs adult offspring bone strength in a mouse model of osteogenesis imperfecta.

Science.gov (United States)

Oestreich, Arin K; Kamp, William M; McCray, Marcus G; Carleton, Stephanie M; Karasseva, Natalia; Lenz, Kristin L; Jeong, Youngjae; Daghlas, Salah A; Yao, Xiaomei; Wang, Yong; Pfeiffer, Ferris M; Ellersieck, Mark R; Schulz, Laura C; Phillips, Charlotte L

2016-11-22

During fetal development, the uterine environment can have effects on offspring bone architecture and integrity that persist into adulthood; however, the biochemical and molecular mechanisms remain unknown. Myostatin is a negative regulator of muscle mass. Parental myostatin deficiency (Mstn tm1Sjl/+ ) increases muscle mass in wild-type offspring, suggesting an intrauterine programming effect. Here, we hypothesized that Mstn tm1Sjl/+ dams would also confer increased bone strength. In wild-type offspring, maternal myostatin deficiency altered fetal growth and calvarial collagen content of newborn mice and conferred a lasting impact on bone geometry and biomechanical integrity of offspring at 4 mo of age, the age of peak bone mass. Second, we sought to apply maternal myostatin deficiency to a mouse model with osteogenesis imperfecta (Col1a2 oim ), a heritable connective tissue disorder caused by abnormalities in the structure and/or synthesis of type I collagen. Femora of male Col1a2 oim/+ offspring from natural mating of Mstn tm1Sjl/+ dams to Col1a2 oim/+ sires had a 15% increase in torsional ultimate strength, a 29% increase in tensile strength, and a 24% increase in energy to failure compared with age, sex, and genotype-matched offspring from natural mating of Col1a2 oim/+ dams to Col1a2 oim/+ sires. Finally, increased bone biomechanical strength of Col1a2 oim/+ offspring that had been transferred into Mstn tm1Sjl/+ dams as blastocysts demonstrated that the effects of maternal myostatin deficiency were conferred by the postimplantation environment. Thus, targeting the gestational environment, and specifically prenatal myostatin pathways, provides a potential therapeutic window and an approach for treating osteogenesis imperfecta.

Natural defects and defects created by ionic implantation in zinc tellurium

International Nuclear Information System (INIS)

Roche, J.P.; Dupuy, M.; Pfister, J.C.

1977-01-01

Various defects have been studied in ZnTe crystals by transmission electron microscope and by scanning electron microscope in cathodo-luminescence mode: grain boundaries, sub-grain boundaries, twins. Ionic implants of boron (100 keV - 2x10 14 and 10 15 ions cm -2 ) were made on these crystals followed by isochrone annealing (30 minutes) of zinc under partial pressure at 550, 650 and 750 0 C. The nature of the defects was determined by transmission electron microscope: these are interstitial loops (b=1/3 ) the size of which varies between 20 A (non-annealed sample) and 180A (annealed at 750 0 C). The transmission electron microscope was also used to make concentration profiles of defects depending on depth. It is found that for the same implant (2x10 14 ions.cm -2 ), the defect peak moves towards the exterior of the crystal as the annealing temperature rises (400 - 1000 and 7000 A for the three annealings). These results are explained from a model which allows for the coalescence of defects and considers the surface of the sample as being the principal source of vacancies. During the annealings, the migration of vacancies brings about the gradual annihilation of the implant defects. The adjustment of certain calculation parameters on the computer result in giving 2 eV as energy value for the formation of vacancies [fr

Modeling the relationships among internal defect features and external Appalachian hardwood log defect indicators

Science.gov (United States)

R. Edward. Thomas

2009-01-01

As a hardwood tree grows and develops, surface defects such as branch stubs and wounds are overgrown. Evidence of these defects remain on the log surface for decades and in many instances for the life of the tree. As the tree grows the defect is encapsulated or grown over by new wood. During this process the appearance of the defect in the tree's bark changes. The...

Automatic classification of blank substrate defects

Science.gov (United States)

Boettiger, Tom; Buck, Peter; Paninjath, Sankaranarayanan; Pereira, Mark; Ronald, Rob; Rost, Dan; Samir, Bhamidipati

2014-10-01

Mask preparation stages are crucial in mask manufacturing, since this mask is to later act as a template for considerable number of dies on wafer. Defects on the initial blank substrate, and subsequent cleaned and coated substrates, can have a profound impact on the usability of the finished mask. This emphasizes the need for early and accurate identification of blank substrate defects and the risk they pose to the patterned reticle. While Automatic Defect Classification (ADC) is a well-developed technology for inspection and analysis of defects on patterned wafers and masks in the semiconductors industry, ADC for mask blanks is still in the early stages of adoption and development. Calibre ADC is a powerful analysis tool for fast, accurate, consistent and automatic classification of defects on mask blanks. Accurate, automated classification of mask blanks leads to better usability of blanks by enabling defect avoidance technologies during mask writing. Detailed information on blank defects can help to select appropriate job-decks to be written on the mask by defect avoidance tools [1][4][5]. Smart algorithms separate critical defects from the potentially large number of non-critical defects or false defects detected at various stages during mask blank preparation. Mechanisms used by Calibre ADC to identify and characterize defects include defect location and size, signal polarity (dark, bright) in both transmitted and reflected review images, distinguishing defect signals from background noise in defect images. The Calibre ADC engine then uses a decision tree to translate this information into a defect classification code. Using this automated process improves classification accuracy, repeatability and speed, while avoiding the subjectivity of human judgment compared to the alternative of manual defect classification by trained personnel [2]. This paper focuses on the results from the evaluation of Automatic Defect Classification (ADC) product at MP Mask

Holographic Chern-Simons defects

International Nuclear Information System (INIS)

Fujita, Mitsutoshi; Melby-Thompson, Charles M.; Meyer, René; Sugimoto, Shigeki

2016-01-01

We study SU(N) Yang-Mills-Chern-Simons theory in the presence of defects that shift the Chern-Simons level from a holographic point of view by embedding the system in string theory. The model is a D3-D7 system in Type IIB string theory, whose gravity dual is given by the AdS soliton background with probe D7 branes attaching to the AdS boundary along the defects. We holographically renormalize the free energy of the defect system with sources, from which we obtain the correlation functions for certain operators naturally associated to these defects. We find interesting phase transitions when the separation of the defects as well as the temperature are varied. We also discuss some implications for the Fractional Quantum Hall Effect and for 2-dimensional QCD.

Point defects in solids

International Nuclear Information System (INIS)

Anon.

1978-01-01

The principal properties of point defects are studied: thermodynamics, electronic structure, interactions with etended defects, production by irradiation. Some measuring methods are presented: atomic diffusion, spectroscopic methods, diffuse scattering of neutron and X rays, positron annihilation, molecular dynamics. Then points defects in various materials are investigated: ionic crystals, oxides, semiconductor materials, metals, intermetallic compounds, carbides, nitrides [fr

Defect detection using transient thermography

International Nuclear Information System (INIS)

Mohd Zaki Umar; Ibrahim Ahmad; Ab Razak Hamzah; Wan Saffiey Wan Abdullah

2008-08-01

An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 kWatt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with ThermofitTMPro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔΤ m ax and the time of its appearance, τ m ax (ΔΤ). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔΤ m ax), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defects are at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (Author)

Essential roles of BCCIP in mouse embryonic development and structural stability of chromosomes.

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Huimei Lu

2011-09-01

Full Text Available BCCIP is a BRCA2- and CDKN1A(p21-interacting protein that has been implicated in the maintenance of genomic integrity. To understand the in vivo functions of BCCIP, we generated a conditional BCCIP knockdown transgenic mouse model using Cre-LoxP mediated RNA interference. The BCCIP knockdown embryos displayed impaired cellular proliferation and apoptosis at day E7.5. Consistent with these results, the in vitro proliferation of blastocysts and mouse embryonic fibroblasts (MEFs of BCCIP knockdown mice were impaired considerably. The BCCIP deficient mouse embryos die before E11.5 day. Deletion of the p53 gene could not rescue the embryonic lethality due to BCCIP deficiency, but partially rescues the growth delay of mouse embryonic fibroblasts in vitro. To further understand the cause of development and proliferation defects in BCCIP-deficient mice, MEFs were subjected to chromosome stability analysis. The BCCIP-deficient MEFs displayed significant spontaneous chromosome structural alterations associated with replication stress, including a 3.5-fold induction of chromatid breaks. Remarkably, the BCCIP-deficient MEFs had a ∼20-fold increase in sister chromatid union (SCU, yet the induction of sister chromatid exchanges (SCE was modestly at 1.5 fold. SCU is a unique type of chromatid aberration that may give rise to chromatin bridges between daughter nuclei in anaphase. In addition, the BCCIP-deficient MEFs have reduced repair of irradiation-induced DNA damage and reductions of Rad51 protein and nuclear foci. Our data suggest a unique function of BCCIP, not only in repair of DNA damage, but also in resolving stalled replication forks and prevention of replication stress. In addition, BCCIP deficiency causes excessive spontaneous chromatin bridges via the formation of SCU, which can subsequently impair chromosome segregations in mitosis and cell division.

The Mouse Genome Database (MGD): facilitating mouse as a model for human biology and disease.

Science.gov (United States)

Eppig, Janan T; Blake, Judith A; Bult, Carol J; Kadin, James A; Richardson, Joel E

2015-01-01

The Mouse Genome Database (MGD, http://www.informatics.jax.org) serves the international biomedical research community as the central resource for integrated genomic, genetic and biological data on the laboratory mouse. To facilitate use of mouse as a model in translational studies, MGD maintains a core of high-quality curated data and integrates experimentally and computationally generated data sets. MGD maintains a unified catalog of genes and genome features, including functional RNAs, QTL and phenotypic loci. MGD curates and provides functional and phenotype annotations for mouse genes using the Gene Ontology and Mammalian Phenotype Ontology. MGD integrates phenotype data and associates mouse genotypes to human diseases, providing critical mouse-human relationships and access to repositories holding mouse models. MGD is the authoritative source of nomenclature for genes, genome features, alleles and strains following guidelines of the International Committee on Standardized Genetic Nomenclature for Mice. A new addition to MGD, the Human-Mouse: Disease Connection, allows users to explore gene-phenotype-disease relationships between human and mouse. MGD has also updated search paradigms for phenotypic allele attributes, incorporated incidental mutation data, added a module for display and exploration of genes and microRNA interactions and adopted the JBrowse genome browser. MGD resources are freely available to the scientific community. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Impairment of Vision in a Mouse Model of Usher Syndrome Type III.

Science.gov (United States)

Tian, Guilian; Lee, Richard; Ropelewski, Philip; Imanishi, Yoshikazu

2016-03-01

The purpose of this study was to obtain an Usher syndrome type III mouse model with retinal phenotype. Speed congenic method was used to obtain Clrn1 exon 1 knockout (Clrn1-/-) and Clrn1N48K knockin (Clrn1N48K/N48K) mice under A/J background. To study the retinal functions of these mice, we measured scotopic and photopic ERG responses. To observe if there are any structural abnormalities, we conducted light and transmission electron microscopy of fixed retinal specimens. In 3-month-old Clrn1-/- mice, scotopic b-wave amplitude was reduced by more than 25% at the light intensities from -2.2 to 0.38 log cd·s/m2, but scotopic a-wave amplitudes were comparable to those of age-matched wild type mice at all the light intensities tested. In 9-month-old Clrn1-/- mice, scotopic b-wave amplitudes were further reduced by more than 35%, and scotopic a-wave amplitude also showed a small decline as compared with wild type mice. Photopic ERG responses were comparable between Clrn1-/- and wild type mice. Those electrophysiological defects were not associated with a loss of rods. In Clrn1N48K/N48K mice, both a- and b-wave amplitudes were not discernable from those of wild type mice aged up to 10 months. Mutations that are Clrn1-/- biallelic cause visual defects when placed under A/J background. The absence of apparent rod degeneration suggests that the observed phenotype is due to functional defects, and not due to loss of rods. Biallelic Clrn1N48K/N48K mutations did not cause discernible visual defects, suggesting that Clrn1- allele is more severely dysfunctional than ClrnN48K allele.

Optimization of the virtual mouse HeadMouse to foster its classroom use by children with physical disabilities

Directory of Open Access Journals (Sweden)

Merce TEIXIDO

2014-03-01

Full Text Available This paper presents the optimization of a virtual mouse called HeadMouse in order to foster its classroom use by children with physical disabilities. HeadMouse is an absolute virtual mouse that converts head movements in cursor displacement and facial gestures in click actions. The virtual mouse combines different image processing algorithms: face detection, pattern matching and optical flow in order to emulate the behaviour of a conventional computer mouse. The original implementation of HeadMouse requires large computational power and this paper proposes specific optimizations in order to enable its use by children with disabilities in standard low cost classroom computers.

A mouse model of harlequin ichthyosis delineates a key role for Abca12 in lipid homeostasis.

Directory of Open Access Journals (Sweden)

Ian Smyth

2008-09-01

Full Text Available Harlequin Ichthyosis (HI is a severe and often lethal hyperkeratotic skin disease caused by mutations in the ABCA12 transport protein. In keratinocytes, ABCA12 is thought to regulate the transfer of lipids into small intracellular trafficking vesicles known as lamellar bodies. However, the nature and scope of this regulation remains unclear. As part of an original recessive mouse ENU mutagenesis screen, we have identified and characterised an animal model of HI and showed that it displays many of the hallmarks of the disease including hyperkeratosis, loss of barrier function, and defects in lipid homeostasis. We have used this model to follow disease progression in utero and present evidence that loss of Abca12 function leads to premature differentiation of basal keratinocytes. A comprehensive analysis of lipid levels in mutant epidermis demonstrated profound defects in lipid homeostasis, illustrating for the first time the extent to which Abca12 plays a pivotal role in maintaining lipid balance in the skin. To further investigate the scope of Abca12's activity, we have utilised cells from the mutant mouse to ascribe direct transport functions to the protein and, in doing so, we demonstrate activities independent of its role in lamellar body function. These cells have severely impaired lipid efflux leading to intracellular accumulation of neutral lipids. Furthermore, we identify Abca12 as a mediator of Abca1-regulated cellular cholesterol efflux, a finding that may have significant implications for other diseases of lipid metabolism and homeostasis, including atherosclerosis.

Defective muscle basement membrane and lack of M-laminin in the dystrophic dy/dy mouse

DEFF Research Database (Denmark)

Xu, H; Christmas, P; Wu, X R

1994-01-01

-linked Duchenne and Becker muscular dystrophies. We have examined M-laminin expression in mice with autosomal recessive muscular dystrophy caused by the mutation dy. The heavy chain of M-laminin was undetectable in skeletal muscle, heart muscle, and peripheral nerve by immunofluorescence and immunoblotting......M-laminin is a major member of the laminin family of basement membrane proteins. It is prominently expressed in striated muscle and peripheral nerve. M-laminin is deficient in patients with the autosomal recessive Fukuyama congenital muscular dystrophy but is normal in patients with the sex...... tissue from dy/dy mice, suggesting that M-laminin heavy-chain mRNA may be produced at very low levels or is unstable. Information about the chromosomal localization of the M heavy-chain in human and mouse suggests that a mutation in the M-chain gene causes the muscular dystrophy in dy/dy mice. The dy...

Effects of androgen on immunohistochemical localization of androgen receptor and Connexin 43 in mouse ovary.

Science.gov (United States)

Yang, Mei; Li, Jianhua; An, Yulin; Zhang, Shuiwen

2015-10-01

Androgens have essential roles in the regulation of follicular development and female fertility. Androgen excess is the leading defect in polycystic ovary syndrome (PCOS) patients and involved in the ovarian dysfunction. The aim of this study was to elucidate the regarding regulatory role of androgen in the follicular development of female mouse. Immunohistochemical staining and Western blot analyses were performed to detect androgen receptor (AR) and Connexin 43 (Cx43) expression in ovaries from both control and testosterone-treated group mice. In this study, localizations of AR and Cx43 were dramatically altered in testosterone-treated mouse ovaries. In addition, AR expression was significantly increased, whereas Cx43 expression was markedly decreased after testosterone treatment. Alterations of AR and Cx43 expression by testosterone with concomitant reduction of MII oocytes. Overall, these results suggest the involvement of androgen in the regulation of AR and Cx43 localizations in mouse ovary. Alterations of AR and Cx43 expression by testosterone may affect normal folliculogenesis. Together these findings will enable us to begin understanding the important roles of AR and Cx43 actions in the regulation of follicular development, as well as providing insights into the role of AR and Cx43 actions in the androgen-associated reproductive diseases such as PCOS. Copyright © 2015 Elsevier Ltd. All rights reserved.

EUV actinic defect inspection and defect printability at the sub-32 nm half pitch

Energy Technology Data Exchange (ETDEWEB)

Huh, Sungmin; Kearney, Patrick; Wurm, Stefan; Goodwin, Frank; Han, Hakseung; Goldberg, Kenneth; Mochi, Iacopp; Gullikson, Eric M.

2009-08-01

Extreme ultraviolet (EUV) mask blanks with embedded phase defects were inspected with a reticle actinic inspection tool (AIT) and the Lasertec M7360. The Lasertec M7360, operated at SEMA TECH's Mask Blank Development Center (MBDC) in Albany, NY, has a sensitivity to multilayer defects down to 40-45 nm, which is not likely sufficient for mask blank development below the 32 nm half-pitch node. Phase defect printability was simulated to calculate the required defect sensitivity for a next generation blank inspection tool to support reticle development for the sub-32 nm half-pitch technology node. Defect mitigation technology is proposed to take advantage of mask blanks with some defects. This technology will reduce the cost of ownership of EUV mask blanks. This paper will also discuss the kind of infrastructure that will be required for the development and mass production stages.

Accurate defect die placement and nuisance defect reduction for reticle die-to-die inspections

Science.gov (United States)

Wen, Vincent; Huang, L. R.; Lin, C. J.; Tseng, Y. N.; Huang, W. H.; Tuo, Laurent C.; Wylie, Mark; Chen, Ellison; Wang, Elvik; Glasser, Joshua; Kelkar, Amrish; Wu, David

2015-10-01

Die-to-die reticle inspections are among the simplest and most sensitive reticle inspections because of the use of an identical-design neighboring-die for the reference image. However, this inspection mode can have two key disadvantages: (1) The location of the defect is indeterminate because it is unclear to the inspector whether the test or reference image is defective; and (2) nuisance and false defects from mask manufacturing noise and tool optical variation can limit the usable sensitivity. The use of a new sequencing approach for a die-to-die inspection can resolve these issues without any additional scan time, without sacrifice in sensitivity requirement, and with a manageable increase in computation load. In this paper we explore another approach for die-to-die inspections using a new method of defect processing and sequencing. Utilizing die-to-die double arbitration during defect detection has been proven through extensive testing to generate accurate placement of the defect in the correct die to ensure efficient defect disposition at the AIMS step. The use of this method maintained the required inspection sensitivity for mask quality as verified with programmed-defectmask qualification and then further validated with production masks comparing the current inspection approach to the new method. Furthermore, this approach can significantly reduce the total number of defects that need to be reviewed by essentially eliminating the nuisance and false defects that can result from a die-to-die inspection. This "double-win" will significantly reduce the effort in classifying a die-to-die inspection result and will lead to improved cycle times.

Multiscale crystal defect dynamics: A coarse-grained lattice defect model based on crystal microstructure

Science.gov (United States)

Lyu, Dandan; Li, Shaofan

2017-10-01

Crystal defects have microstructure, and this microstructure should be related to the microstructure of the original crystal. Hence each type of crystals may have similar defects due to the same failure mechanism originated from the same microstructure, if they are under the same loading conditions. In this work, we propose a multiscale crystal defect dynamics (MCDD) model that models defects by considering its intrinsic microstructure derived from the microstructure or material genome of the original perfect crystal. The main novelties of present work are: (1) the discrete exterior calculus and algebraic topology theory are used to construct a scale-up (coarse-grained) dual lattice model for crystal defects, which may represent all possible defect modes inside a crystal; (2) a higher order Cauchy-Born rule (up to the fourth order) is adopted to construct atomistic-informed constitutive relations for various defect process zones, and (3) an hierarchical strain gradient theory based finite element formulation is developed to support an hierarchical multiscale cohesive (process) zone model for various defects in a unified formulation. The efficiency of MCDD computational algorithm allows us to simulate dynamic defect evolution at large scale while taking into account atomistic interaction. The MCDD model has been validated by comparing of the results of MCDD simulations with that of molecular dynamics (MD) in the cases of nanoindentation and uniaxial tension. Numerical simulations have shown that MCDD model can predict dislocation nucleation induced instability and inelastic deformation, and thus it may provide an alternative solution to study crystal plasticity.

Deletion of ETS-1, a gene in the Jacobsen syndrome critical region, causes ventricular septal defects and abnormal ventricular morphology in mice

Science.gov (United States)

Ye, Maoqing; Coldren, Chris; Liang, Xingqun; Mattina, Teresa; Goldmuntz, Elizabeth; Benson, D. Woodrow; Ivy, Dunbar; Perryman, M.B.; Garrett-Sinha, Lee Ann; Grossfeld, Paul

2010-01-01

Congenital heart defects comprise the most common form of major birth defects, affecting 0.7% of all newborn infants. Jacobsen syndrome (11q-) is a rare chromosomal disorder caused by deletions in distal 11q. We have previously determined that a wide spectrum of the most common congenital heart defects occur in 11q-, including an unprecedented high frequency of hypoplastic left heart syndrome (HLHS). We identified an ∼7 Mb ‘cardiac critical region’ in distal 11q that contains a putative causative gene(s) for congenital heart disease. In this study, we utilized chromosomal microarray mapping to characterize three patients with 11q- and congenital heart defects that carry interstitial deletions overlapping the 7 Mb cardiac critical region. We propose that this 1.2 Mb region of overlap harbors a gene(s) that causes at least a subset of the congenital heart defects that occur in 11q-. We demonstrate that one gene in this region, ETS-1 (a member of the ETS family of transcription factors), is expressed in the endocardium and neural crest during early mouse heart development. Gene-targeted deletion of ETS-1 in mice in a C57/B6 background causes, with high penetrance, large membranous ventricular septal defects and a bifid cardiac apex, and less frequently a non-apex-forming left ventricle (one of the hallmarks of HLHS). Our results implicate an important role for the ETS-1 transcription factor in mammalian heart development and should provide important insights into some of the most common forms of congenital heart disease. PMID:19942620

Surface defects and chiral algebras

Energy Technology Data Exchange (ETDEWEB)

Córdova, Clay [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, NJ 08540 (United States); Gaiotto, Davide [Perimeter Institute for Theoretical Physics,31 Caroline St N, Waterloo, ON N2L 2Y5 (Canada); Shao, Shu-Heng [School of Natural Sciences, Institute for Advanced Study,1 Einstein Dr, Princeton, NJ 08540 (United States)

2017-05-26

We investigate superconformal surface defects in four-dimensional N=2 superconformal theories. Each such defect gives rise to a module of the associated chiral algebra and the surface defect Schur index is the character of this module. Various natural chiral algebra operations such as Drinfeld-Sokolov reduction and spectral flow can be interpreted as constructions involving four-dimensional surface defects. We compute the index of these defects in the free hypermultiplet theory and Argyres-Douglas theories, using both infrared techniques involving BPS states, as well as renormalization group flows onto Higgs branches. In each case we find perfect agreement with the predicted characters.

Laterality defects in the national birth defects prevention study 1998-2007 birth prevalence and descriptive epidemiology

Science.gov (United States)

Little is known epidemiologically about laterality defects. Using data from the National Birth Defects Prevention Study (NBDPS), a large multi-site case-control study of birth defects, we analyzed prevalence and selected characteristics in children born with laterality defects born from 1998 to 2007...

Injurious Effects of Curcumin on Maturation of Mouse Oocytes, Fertilization and Fetal Development via Apoptosis

Directory of Open Access Journals (Sweden)

Wen-Hsiung Chan

2012-04-01

Full Text Available Curcumin, a common dietary pigment and spice, is a hydrophobic polyphenol derived from the rhizome of the herb Curcuma longa. Previously, we reported a cytotoxic effect of curcumin on mouse embryonic stem cells and blastocysts and its association with defects in subsequent development. In the present study, we further investigated the effects of curcumin on oocyte maturation and subsequent pre- and post-implantation development, both in vitro and in vivo. Notably, curcumin induced a significant reduction in the rate of oocyte maturation, fertilization, and in vitro embryonic development. Treatment of oocytes with curcumin during in vitro maturation (IVM led to increased resorption of postimplantation embryos and decreased fetal weight. Experiments with an in vivo mouse model disclosed that consumption of drinking water containing 40 μM curcumin led to decreased oocyte maturation and in vitro fertilization as well as early embryonic developmental injury. Finally, pretreatment with a caspase-3-specific inhibitor effectively prevented curcumin-triggered injury effects, suggesting that embryo impairment by curcumin occurs mainly via a caspase-dependent apoptotic process.

Recql4 haploinsufficiency in mice leads to defects in osteoblast progenitors: Implications for low bone mass phenotype

International Nuclear Information System (INIS)

Yang Jieping; Murthy, Sreemala; Winata, Therry; Werner, Sean; Abe, Masumi; Prahalad, Agasanur K.; Hock, Janet M.

2006-01-01

The cellular and molecular mechanisms that underlie skeletal abnormalities in defective Recql4-related syndromes are poorly understood. Our objective in this study was to explore the function of Recql4 in osteoblast biology both in vitro and in vivo. Immunohistochemistry on adult mouse bone showed Recql4 protein localization in active osteoblasts around growth plate, but not in fully differentiated osteocytes. Consistent with this finding, Recql4 gene expression was high in proliferating mouse osteoblastic MC3T3.E1 cells and decreased as cells progressively lost their proliferation activity during differentiation. Recql4 overexpression in osteoblastic cells exhibited higher proliferation activity, while its depletion impeded cell growth. In addition, bone marrow stromal cells from male Recql4+/- mice had fewer progenitor cells, including osteoprogenitors, indicated by reduced total fibroblast colony forming units (CFU-f) and alkaline phosphatase-positive CFU-f colonies concomitant with reduced bone mass. These findings provide evidence that Recql4 functions as a regulatory protein during osteoprogenitor proliferation, a critical cellular event during skeleton development

Nuclear Factor-kappaB in Autoimmunity: Man and Mouse.

Science.gov (United States)

Miraghazadeh, Bahar; Cook, Matthew C

2018-01-01

NF-κB (nuclear factor-kappa B) is a transcription complex crucial for host defense mediated by innate and adaptive immunity, where canonical NF-κB signaling, mediated by nuclear translocation of RelA, c-Rel, and p50, is important for immune cell activation, differentiation, and survival. Non-canonical signaling mediated by nuclear translocation of p52 and RelB contributes to lymphocyte maturation and survival and is also crucial for lymphoid organogenesis. We outline NF-κB signaling and regulation, then summarize important molecular contributions of NF-κB to mechanisms of self-tolerance. We relate these mechanisms to autoimmune phenotypes described in what is now a substantial catalog of immune defects conferred by mutations in NF-κB pathways in mouse models. Finally, we describe Mendelian autoimmune syndromes arising from human NF-κB mutations, and speculate on implications for understanding sporadic autoimmune disease.

Targeted disruption of the mouse Lipoma Preferred Partner gene

International Nuclear Information System (INIS)

Vervenne, Hilke B.V.K.; Crombez, Koen R.M.O.; Delvaux, Els L.; Janssens, Veerle; Ven, Wim J.M. van de; Petit, Marleen M.R.

2009-01-01

LPP (Lipoma Preferred Partner) is a zyxin-related cell adhesion protein that is involved in the regulation of cell migration. We generated mice with a targeted disruption of the Lpp gene and analysed the importance of Lpp for embryonic development and adult functions. Aberrant Mendelian inheritance in heterozygous crosses suggested partial embryonic lethality of Lpp -/- females. Fertility of Lpp -/- males was proven to be normal, however, females from Lpp -/- x Lpp -/- crosses produced a strongly reduced number of offspring, probably due to a combination of female embryonic lethality and aberrant pregnancies. Apart from these developmental and reproductive abnormalities, Lpp -/- mice that were born reached adulthood without displaying any additional macroscopic defects. On the other hand, Lpp -/- mouse embryonic fibroblasts exhibited reduced migration capacity, reduced viability, and reduced expression of some Lpp interaction partners. Finally, we discovered a short nuclear form of Lpp, expressed mainly in testis via an alternative promoter.

Defects at oxide surfaces

CERN Document Server

Thornton, Geoff

2015-01-01

This book presents the basics and characterization of defects at oxide surfaces. It provides a state-of-the-art review of the field, containing information to the various types of surface defects, describes analytical methods to study defects, their chemical activity and the catalytic reactivity of oxides. Numerical simulations of defective structures complete the picture developed. Defects on planar surfaces form the focus of much of the book, although the investigation of powder samples also form an important part. The experimental study of planar surfaces opens the possibility of applying the large armoury of techniques that have been developed over the last half-century to study surfaces in ultra-high vacuum. This enables the acquisition of atomic level data under well-controlled conditions, providing a stringent test of theoretical methods. The latter can then be more reliably applied to systems such as nanoparticles for which accurate methods of characterization of structure and electronic properties ha...

48 CFR 1615.407-1 - Rate reduction for defective pricing or defective cost or pricing data.

Science.gov (United States)

2010-10-01

... defective pricing or defective cost or pricing data. 1615.407-1 Section 1615.407-1 Federal Acquisition... CONTRACTING METHODS AND CONTRACT TYPES CONTRACTING BY NEGOTIATION Contract Pricing 1615.407-1 Rate reduction for defective pricing or defective cost or pricing data. The clause set forth in section 1652.215-70...

48 CFR 1652.215-70 - Rate Reduction for Defective Pricing or Defective Cost or Pricing Data.

Science.gov (United States)

2010-10-01

... Defective Pricing or Defective Cost or Pricing Data. 1652.215-70 Section 1652.215-70 Federal Acquisition... CLAUSES AND FORMS CONTRACT CLAUSES Texts of FEHBP Clauses 1652.215-70 Rate Reduction for Defective Pricing or Defective Cost or Pricing Data. As prescribed in 1615.407-1, the following clause shall be...

Connective Tissue Growth Factor Transgenic Mouse Develops Cardiac Hypertrophy, Lean Body Mass and Alopecia.

Science.gov (United States)

Nuglozeh, Edem

2017-07-01

Connective Tissue Growth Factor (CTGF/CCN2) is one of the six members of cysteine-rich, heparin-binding proteins, secreted as modular protein and recognised to play a major function in cell processes such as adhesion, migration, proliferation and differentiation as well as chondrogenesis, skeletogenesis, angiogenesis and wound healing. The capacity of CTGF to interact with different growth factors lends an important role during early and late development, especially in the anterior region of the embryo. CTGF Knockout (KO) mice have several craniofacial defects and bone miss shaped due to an impairment of the vascular system development during chondrogenesis. The aim of the study was to establish an association between multiple modular functions of CTGF and the phenotype and cardiovascular functions in transgenic mouse. Bicistronic cassette was constructed using pIRES expressing vector (Clontech, Palo Alto, CA). The construct harbours mouse cDNA in tandem with LacZ cDNA as a reporter gene under the control of Cytomegalovirus (CMV) promoter. The plasmid was linearised with NotI restriction enzyme, and 50 ng of linearised plasmid was injected into mouse pronucleus for the chimaera production. Immunohistochemical methods were used to assess the colocalisation renin and CTGF as well as morphology and rheology of the cardiovascular system. The chimeric mice were backcrossed against the wild-type C57BL/6 to generate hemizygous (F1) mouse. Most of the offsprings died as a result of respiratory distress and those that survived have low CTGF gene copy number, approximately 40 molecules per mouse genome. The copy number assessment on the dead pups showed 5×10 3 molecules per mouse genome explaining the threshold of the gene in terms of toxicity. Interestingly, the result of this cross showed 85% of the progenies to be positive deviating from Mendelian first law. All F2 progenies died excluding the possibility of establishing the CTGF transgenic mouse line, situation that

Point defects in platinum

International Nuclear Information System (INIS)

Piercy, G.R.

1960-01-01

An investigation was made of the mobility and types of point defect introduced in platinum by deformation in liquid nitrogen, quenching into water from 1600 o C, or reactor irradiation at 50 o C. In all cases the activation energy for motion of the defect was determined from measurements of electrical resistivity. Measurements of density, hardness, and x-ray line broadening were also made there applicable. These experiments indicated that the principal defects remaining in platinum after irradiation were single vacant lattice sites and after quenching were pairs of vacant lattice sites. Those present after deformation In liquid nitrogen were single vacant lattice sites and another type of defect, perhaps interstitial atoms. (author)

Development of mPMab-1, a Mouse-Rat Chimeric Antibody Against Mouse Podoplanin.

Science.gov (United States)

Yamada, Shinji; Kaneko, Mika K; Nakamura, Takuro; Ichii, Osamu; Konnai, Satoru; Kato, Yukinari

2017-04-01

Podoplanin (PDPN), the ligand of C-type lectin-like receptor-2, is used as a lymphatic endothelial marker. We previously established clone PMab-1 of rat IgG 2a as a specific monoclonal antibody (mAb) against mouse PDPN. PMab-1 is also very sensitive in immunohistochemical analysis; however, rat mAbs seem to be unfavorable for pathologists because anti-mouse IgG and anti-rabbit IgG are usually used as secondary antibodies in commercially available kits for immunohistochemical analysis. In this study, we develop a mouse-rat chimeric antibody, mPMab-1 of mouse IgG 2a , which was derived from rat PMab-1 mAb. Immunohistochemical analysis shows that mPMab-1 detects podocytes of the kidney, lymphatic endothelial cells of the colon, and type I alveolar cells of the lung. Importantly, mPMab-1 is more sensitive than PMab-1. This conversion strategy from rat mAb to mouse mAb could be applicable to other mAbs.

The phenotype of FancB-mutant mouse embryonic stem cells

International Nuclear Information System (INIS)

Kim, Tae Moon; Ko, Jun Ho; Choi, Yong Jun; Hu Lingchuan; Hasty, Paul

2011-01-01

Fanconi anemia (FA) is a rare autosomal recessive disease characterized by bone marrow failure, developmental defects and cancer. There are multiple FA genes that enable the repair of interstrand crosslinks (ICLs) in coordination with a variety of other DNA repair pathways in a way that is poorly understood. Here we present the phenotype of mouse embryonic stem (ES) cells mutated for FancB. We found FancB-mutant cells exhibited reduced cellular proliferation, hypersensitivity to the crosslinking agent mitomycin C (MMC), increased spontaneous and MMC-induced chromosomal abnormalities, reduced spontaneous sister chromatid exchanges (SCEs), reduced gene targeting, reduced MMC-induced Rad51 foci and absent MMC-induced FancD2 foci. Since FancB is on the X chromosome and since ES cells are typically XY, FancB is an excellent target for an epistatic analysis to elucidate FA's role in ICL repair.

Mutations in Dnaaf1 and Lrrc48 Cause Hydrocephalus, Laterality Defects, and Sinusitis in Mice

Directory of Open Access Journals (Sweden)

Seungshin Ha

2016-08-01

Full Text Available We have previously described a forward genetic screen in mice for abnormalities of brain development. Characterization of two hydrocephalus mutants by whole-exome sequencing after whole-genome SNP mapping revealed novel recessive mutations in Dnaaf1 and Lrrc48. Mouse mutants of these two genes have not been previously reported. The Dnaaf1 mutant carries a mutation at the splice donor site of exon 4, which results in abnormal transcripts. The Lrrc48 mutation is a missense mutation at a highly conserved leucine residue, which is also associated with a decrease in Lrrc48 transcription. Both Dnaaf1 and Lrrc48 belong to a leucine-rich repeat-containing protein family and are components of the ciliary axoneme. Their Chlamydomonas orthologs are known to be required for normal ciliary beat frequency or flagellar waveform, respectively. Some Dnaaf1 or Lrrc48 homozygote mutants displayed laterality defects, suggesting a motile cilia defect in the embryonic node. Mucus accumulation and neutrophil infiltration in the maxillary sinuses suggested sinusitis. Dnaaf1 mutants showed postnatal lethality, and none survived to weaning age. Lrrc48 mutants survive to adulthood, but had male infertility. ARL13B immunostaining showed the presence of motile cilia in the mutants, and the distal distribution of DNAH9 in the axoneme of upper airway motile cilia appeared normal. The phenotypic abnormalities suggest that mutations in Dnaaf1 and Lrrc48 cause defects in motile cilia function.

Gene expression profile data for mouse facial development

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Sonia M. Leach

2017-08-01

Full Text Available This article contains data related to the research articles "Spatial and Temporal Analysis of Gene Expression during Growth and Fusion of the Mouse Facial Prominences" (Feng et al., 2009 [1] and “Systems Biology of facial development: contributions of ectoderm and mesenchyme” (Hooper et al., 2017 In press [2]. Embryonic mammalian craniofacial development is a complex process involving the growth, morphogenesis, and fusion of distinct facial prominences into a functional whole. Aberrant gene regulation during this process can lead to severe craniofacial birth defects, including orofacial clefting. As a means to understand the genes involved in facial development, we had previously dissected the embryonic mouse face into distinct prominences: the mandibular, maxillary or nasal between E10.5 and E12.5. The prominences were then processed intact, or separated into ectoderm and mesenchyme layers, prior analysis of RNA expression using microarrays (Feng et al., 2009, Hooper et al., 2017 in press [1,2]. Here, individual gene expression profiles have been built from these datasets that illustrate the timing of gene expression in whole prominences or in the separated tissue layers. The data profiles are presented as an indexed and clickable list of the genes each linked to a graphical image of that gene׳s expression profile in the ectoderm, mesenchyme, or intact prominence. These data files will enable investigators to obtain a rapid assessment of the relative expression level of any gene on the array with respect to time, tissue, prominence, and expression trajectory.

On the influence of extrinsic point defects on irradiation-induced point-defect distributions in silicon

International Nuclear Information System (INIS)

Vanhellemont, J.; Romano-Rodriguez, A.

1994-01-01

A semi-quantitative model describing the influence of interfaces and stress fields on {113}-defect generation in silicon during 1-MeV electron irradiation, is further developed to take into account also the role of extrinsic point defects. It is shown that the observed distribution of {113}-defects in high-flux electron-irradiated silicon and its dependence on irradiation temperature and dopant concentration can be understood by taking into account not only the influence of the surfaces and interfaces as sinks for intrinsic point defects but also the thermal stability of the bulk sinks for intrinsic point defects. In heavily doped silicon the bulk sinks are related with pairing reactions of the dopant atoms with the generated intrinsic point defects or related with enhanced recombination of vacancies and self-interstitials at extrinsic point defects. The obtained theoretical results are correlated with published experimental data on boron-and phosphorus-doped silicon and are illustrated with observations obtained by irradiating cross-section transmission electron microscopy samples of wafer with highly doped surface layers. (orig.)

Gaze beats mouse

DEFF Research Database (Denmark)

Mateo, Julio C.; San Agustin, Javier; Hansen, John Paulin

2008-01-01

Facial EMG for selection is fast, easy and, combined with gaze pointing, it can provide completely hands-free interaction. In this pilot study, 5 participants performed a simple point-and-select task using mouse or gaze for pointing and a mouse button or a facial-EMG switch for selection. Gaze...

Molecular hierarchy in neurons differentiated from mouse ES cells containing a single human chromosome 21.

Science.gov (United States)

Wang, Chi Chiu; Kadota, Mitsutaka; Nishigaki, Ryuichi; Kazuki, Yasuhiro; Shirayoshi, Yasuaki; Rogers, Michael Scott; Gojobori, Takashi; Ikeo, Kazuho; Oshimura, Mitsuo

2004-02-06

Defects in neurogenesis and neuronal differentiation in the fetal brain of Down syndrome (DS) patients lead to the apparent neuropathological abnormalities and contribute to the phenotypic characters of mental retardation, and premature development of Alzheimer's disease, those being the most common phenotype in DS. In order to understand the molecular mechanism underlying the cause of phenotypic abnormalities in the DS brain, we have utilized an in vitro model of TT2F mouse embryonic stem cells containing a single human chromosome 21 (hChr21) to study neuron development and neuronal differentiation by microarray containing 15K developmentally expressed cDNAs. Defective neuronal differentiation in the presence of extra hChr21 manifested primarily the post-transcriptional and translational modification, such as Mrpl10, SNAPC3, Srprb, SF3a60 in the early neuronal stem cell stage, and Mrps18a, Eef1g, and Ubce8 in the late differentiated stage. Hierarchical clustering patterned specific expression of hChr21 gene dosage effects on neuron outgrowth, migration, and differentiation, such as Syngr2, Dncic2, Eif3sf, and Peg3.

Dwarfism and age-associated spinal degeneration of heterozygote cmd mice defective in aggrecan

Science.gov (United States)

Watanabe, Hideto; Nakata, Ken; Kimata, Koji; Nakanishi, Isao; Yamada, Yoshihiko

1997-01-01

Mouse cartilage matrix deficiency (cmd) is an autosomal recessive disorder caused by a genetic defect of aggrecan, a large chondroitin sulfate proteoglycan in cartilage. The homozygotes (−/−) are characterized by cleft palate and short limbs, tail, and snout. They die just after birth because of respiratory failure, and the heterozygotes (+/−) appear normal at birth. Here we report that the heterozygotes show dwarfism and develop spinal misalignment with age. Within 19 months of age, they exhibit spastic gait caused by misalignment of the cervical spine and die because of starvation. Histological examination revealed a high incidence of herniation and degeneration of vertebral discs. Electron microscopy showed a degeneration of disc chondrocytes in the heterozygotes. These findings may facilitate the identification of mutations in humans predisposed to spinal degeneration. PMID:9192671

Congenital Heart Defects and CCHD

Science.gov (United States)

... and more. Stony Point, NY 10980 Close X Home > Complications & Loss > Birth defects & other health conditions > Congenital heart defects and ... in congenital heart defects. You have a family history of congenital heart ... syndrome or VCF. After birth Your baby may be tested for CCHD as ...

Neutron diffraction and lattice defects

International Nuclear Information System (INIS)

Hamaguchi, Yoshikazu

1974-01-01

Study on lattice defects by neutron diffraction technique is described. Wave length of neutron wave is longer than that of X-ray, and absorption cross-section is small. Number of defects observed by ESR is up to several defects, and the number studied with electron microscopes is more than 100. Information obtained by neutron diffraction concerns the number of defects between these two ranges. For practical analysis, several probable models are selected from the data of ESR or electron microscopes, and most probable one is determined by calculation. Then, defect concentration is obtained from scattering cross section. It is possible to measure elastic scattering exclusively by neutron diffraction. Minimum detectable concentration estimated is about 0.5% and 10 20 - 10 21 defects per unit volume. A chopper and a time of flight system are used as a measuring system. Cold neutrons are obtained from the neutron sources inserted into reactors. Examples of measurements by using similar equipments to PTNS-I system of Japan Atomic Energy Research Institute are presented. Interstitial concentration in the graphite irradiated by fast neutrons is shown. Defects in irradiated MgO were also investigated by measuring scattering cross section. Study of defects in Ge was made by measuring total cross section, and model analysis was performed in comparison with various models. (Kato, T.)

A missing piece: the spiny mouse and the puzzle of menstruating species.

Science.gov (United States)

Bellofiore, Nadia; Cousins, Fiona; Temple-Smith, Peter; Dickinson, Hayley; Evans, Jemma

2018-07-01

We recently discovered the first known menstruating rodent. With the exception of four bats and the elephant shrew, the common spiny mouse ( Acomys cahirinus ) is the only species outside the primate order to exhibit menses. There are few widely accepted theories on why menstruation developed as the preferred reproductive strategy of these select mammals, all of which reference the evolution of spontaneous decidualisation prior to menstrual shedding. Though menstruating species share several reproductive traits, there has been no identifiable feature unique to menstruating species. Such a feature might suggest why spontaneous decidualisation, and thus menstruation, evolved in these species. We propose that a ≥3-fold increase in progesterone during the luteal phase of the reproductive cycle is a unique characteristic linking menstruating species. We discuss spontaneous decidualisation as a consequence of high progesterone, and the potential role of prolactin in screening for defective embryos in these species to aid in minimising implantation of abnormal embryos. We further explore the possible impact of nutrition in selecting species to undergo spontaneous decidualisation and subsequent menstruation. We summarise the current knowledge of menstruation, discuss current pre-clinical models of menstruation and how the spiny mouse may benefit advancing our understanding of this rare biological phenomenon. © 2018 Society for Endocrinology.

UTX and UTY demonstrate histone demethylase-independent function in mouse embryonic development.

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Karl B Shpargel

2012-09-01

Full Text Available UTX (KDM6A and UTY are homologous X and Y chromosome members of the Histone H3 Lysine 27 (H3K27 demethylase gene family. UTX can demethylate H3K27; however, in vitro assays suggest that human UTY has lost enzymatic activity due to sequence divergence. We produced mouse mutations in both Utx and Uty. Homozygous Utx mutant female embryos are mid-gestational lethal with defects in neural tube, yolk sac, and cardiac development. We demonstrate that mouse UTY is devoid of in vivo demethylase activity, so hemizygous X(Utx- Y(+ mutant male embryos should phenocopy homozygous X(Utx- X(Utx- females. However, X(Utx- Y(+ mutant male embryos develop to term; although runted, approximately 25% survive postnatally reaching adulthood. Hemizygous X(+ Y(Uty- mutant males are viable. In contrast, compound hemizygous X(Utx- Y(Uty- males phenocopy homozygous X(Utx- X(Utx- females. Therefore, despite divergence of UTX and UTY in catalyzing H3K27 demethylation, they maintain functional redundancy during embryonic development. Our data suggest that UTX and UTY are able to regulate gene activity through demethylase independent mechanisms. We conclude that UTX H3K27 demethylation is non-essential for embryonic viability.

Varying stiffness and load distributions in defective ball bearings: Analytical formulation and application to defect size estimation

Science.gov (United States)

Petersen, Dick; Howard, Carl; Prime, Zebb

2015-02-01

This paper presents an analytical formulation of the load distribution and varying effective stiffness of a ball bearing assembly with a raceway defect of varying size, subjected to static loading in the radial, axial and rotational degrees of freedom. The analytical formulation is used to study the effect of the size of the defect on the load distribution and varying stiffness of the bearing assembly. The study considers a square-shaped outer raceway defect centered in the load zone and the bearing is loaded in the radial and axial directions while the moment loads are zero. Analysis of the load distributions shows that as the defect size increases, defect-free raceway sections are subjected to increased static loading when one or more balls completely or partly destress when positioned in the defect zone. The stiffness variations that occur when balls pass through the defect zone are significantly larger and change more rapidly at the defect entrance and exit than the stiffness variations that occur for the defect-free bearing case. These larger, more rapid stiffness variations generate parametric excitations which produce the low frequency defect entrance and exit events typically observed in the vibration response of a bearing with a square-shaped raceway defect. Analysis of the stiffness variations further shows that as the defect size increases, the mean radial stiffness decreases in the loaded radial and axial directions and increases in the unloaded radial direction. The effects of such stiffness changes on the low frequency entrance and exit events in the vibration response are simulated with a multi-body nonlinear dynamic model. Previous work used the time difference between the low frequency entrance event and the high frequency exit event to estimate the size of the defect. However, these previous defect size estimation techniques cannot distinguish between defects that differ in size by an integer number of the ball angular spacing, and a third feature

Otitis Media in a New Mouse Model for CHARGE Syndrome with a Deletion in the Chd7 Gene

Science.gov (United States)

Tian, Cong; Yu, Heping; Yang, Bin; Han, Fengchan; Zheng, Ye; Bartels, Cynthia F.; Schelling, Deborah; Arnold, James E.; Scacheri, Peter C.; Zheng, Qing Yin

2012-01-01

Otitis media is a middle ear disease common in children under three years old. Otitis media can occur in normal individuals with no other symptoms or syndromes, but it is often seen in individuals clinically diagnosed with genetic diseases such as CHARGE syndrome, a complex genetic disease caused by mutation in the Chd7 gene and characterized by multiple birth defects. Although otitis media is common in human CHARGE syndrome patients, it has not been reported in mouse models of CHARGE syndrome. In this study, we report a mouse model with a spontaneous deletion mutation in the Chd7 gene and with chronic otitis media of early onset age accompanied by hearing loss. These mice also exhibit morphological alteration in the Eustachian tubes, dysregulation of epithelial proliferation, and decreased density of middle ear cilia. Gene expression profiling revealed up-regulation of Muc5ac, Muc5b and Tgf-β1 transcripts, the products of which are involved in mucin production and TGF pathway regulation. This is the first mouse model of CHARGE syndrome reported to show otitis media with effusion and it will be valuable for studying the etiology of otitis media and other symptoms in CHARGE syndrome. PMID:22539951

Computer simulation of defect cluster

Energy Technology Data Exchange (ETDEWEB)

Kuramoto, Eiichi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

1996-04-01

In order to elucidate individual element process of various defects and defect clusters of used materials under irradiation environments, interatomic potential with reliability was investigated. And for comparison with experimental results, it is often required to adopt the temperature effect and to investigate in details mechanism of one dimensional motion of micro conversion loop and so forth using the molecular dynamic (MD) method. Furthermore, temperature effect is also supposed for stable structure of defects and defect clusters, and many problems relating to alloy element are also remained. And, simulation on photon life at the defects and defect clusters thought to be important under comparison with equipment can also be supposed an improvement of effectiveness due to relation to theses products. In this paper, some topics in such flow was extracted to explain them. In particular, future important problems will be potential preparation of alloy, structure, dynamic behavior and limited temperature of intralattice atomic cluster. (G.K.)

Cell context-specific expression of primary cilia in the human testis and ciliary coordination of Hedgehog signalling in mouse Leydig cells

DEFF Research Database (Denmark)

Berg Nygaard, Marie; Almstrup, Kristian; Lindbæk, Louise

2015-01-01

Primary cilia are sensory organelles that coordinate numerous cellular signalling pathways during development and adulthood. Defects in ciliary assembly or function lead to a series of developmental disorders and diseases commonly referred to as ciliopathies. Still, little is known about...... cells of mature seminiferous epithelium, but present in Sertoli cell-only tubules in Klinefelter syndrome testis. Peritubular cells in atrophic testis produce overly long cilia. Furthermore cultures of growth-arrested immature mouse Leydig cells express primary cilia that are enriched in components...

Norwegian Pitched Roof Defects

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Lars Gullbrekken

2016-06-01

Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

2,3,7,8-Tetrachlorodibenzo-p-dioxin specifically reduces mRNA for the mineralization-related dentin sialophosphoprotein in cultured mouse embryonic molar teeth

International Nuclear Information System (INIS)

Kiukkonen, Anu; Sahlberg, Carin; Lukinmaa, Pirjo-Liisa; Alaluusua, Satu; Peltonen, Eija; Partanen, Anna-Maija

2006-01-01

Previous studies show that the most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), interferes with mineralization of the dental matrices in developing mouse and rat teeth. Culture of mouse embryonic molar teeth with TCDD leads to the failure of enamel to be deposited and dentin to undergo mineralization. Lactationally exposed rats show defectively matured enamel and retardation of dentin mineralization. To see if the impaired mineralization is associated with changes in the expression of dentin sialophosphoprotein (Dspp), Bono1 and/or matrix metalloproteinase-20 (MMP-20), thought to be involved in mineralization of the dental hard tissues, we cultured mouse (NMRI) E18 mandibular molars for 3, 5 or 7 days and exposed them to 1 μM TCDD after 2 days of culture. As detected by in situ hybridization of tissue sections, localization and intensity of Bono1 and MMP-20 expression showed no definite difference between the control and exposed tooth explants, suggesting that TCDD does not affect their expression. On the contrary, TCDD reduced or prevented the expression of Dspp in secretory odontoblasts and decreased it in presecretory ameloblasts. The results suggest that the retardation of dentin mineralization by TCDD in mouse molar teeth involves specific interference with Dspp expression

Congenital platelet function defects

Science.gov (United States)

... pool disorder; Glanzmann's thrombasthenia; Bernard-Soulier syndrome; Platelet function defects - congenital ... Congenital platelet function defects are bleeding disorders that cause reduced platelet function. Most of the time, people with these disorders have ...

Metallography of defects

International Nuclear Information System (INIS)

Borisova, E.A.; Bochvar, G.A.; Brun, M.Ya.

1980-01-01

Different types of defects of metallurgical, technological and exploitation origin in intermediate and final products of titanium alloys, are considered. The examples of metallic and nonmetallic inclusions, chemical homogeneity, different grains, bands, cracks, places of searing, porosity are given; methods of detecting the above defects are described. The methods of metallography, X-ray spectral analysis, measuring microhardness are used

Mouse Model Resources for Vision Research

Directory of Open Access Journals (Sweden)

Jungyeon Won

2011-01-01

Full Text Available The need for mouse models, with their well-developed genetics and similarity to human physiology and anatomy, is clear and their central role in furthering our understanding of human disease is readily apparent in the literature. Mice carrying mutations that alter developmental pathways or cellular function provide model systems for analyzing defects in comparable human disorders and for testing therapeutic strategies. Mutant mice also provide reproducible, experimental systems for elucidating pathways of normal development and function. Two programs, the Eye Mutant Resource and the Translational Vision Research Models, focused on providing such models to the vision research community are described herein. Over 100 mutant lines from the Eye Mutant Resource and 60 mutant lines from the Translational Vision Research Models have been developed. The ocular diseases of the mutant lines include a wide range of phenotypes, including cataracts, retinal dysplasia and degeneration, and abnormal blood vessel formation. The mutations in disease genes have been mapped and in some cases identified by direct sequencing. Here, we report 3 novel alleles of Crxtvrm65, Rp1tvrm64, and Rpe65tvrm148 as successful examples of the TVRM program, that closely resemble previously reported knockout models.

Eccentric localization of catalase to protect chromosomes from oxidative damages during meiotic maturation in mouse oocytes.

Science.gov (United States)

Park, Yong Seok; You, Seung Yeop; Cho, Sungrae; Jeon, Hyuk-Joon; Lee, Sukchan; Cho, Dong-Hyung; Kim, Jae-Sung; Oh, Jeong Su

2016-09-01

The maintenance of genomic integrity and stability is essential for the survival of every organism. Unfortunately, DNA is vulnerable to attack by a variety of damaging agents. Oxidative stress is a major cause of DNA damage because reactive oxygen species (ROS) are produced as by-products of normal cellular metabolism. Cells have developed eloquent antioxidant defense systems to protect themselves from oxidative damage along with aerobic metabolism. Here, we show that catalase (CAT) is present in mouse oocytes to protect the genome from oxidative damage during meiotic maturation. CAT was expressed in the nucleus to form unique vesicular structures. However, after nuclear envelope breakdown, CAT was redistributed in the cytoplasm with particular focus at the chromosomes. Inhibition of CAT activity increased endogenous ROS levels, but did not perturb meiotic maturation. In addition, CAT inhibition produced chromosomal defects, including chromosome misalignment and DNA damage. Therefore, our data suggest that CAT is required not only to scavenge ROS, but also to protect DNA from oxidative damage during meiotic maturation in mouse oocytes.

Blockade of PI3Kgamma suppresses joint inflammation and damage in mouse models of rheumatoid arthritis.

Science.gov (United States)

Camps, Montserrat; Rückle, Thomas; Ji, Hong; Ardissone, Vittoria; Rintelen, Felix; Shaw, Jeffrey; Ferrandi, Chiara; Chabert, Christian; Gillieron, Corine; Françon, Bernard; Martin, Thierry; Gretener, Denise; Perrin, Dominique; Leroy, Didier; Vitte, Pierre-Alain; Hirsch, Emilio; Wymann, Matthias P; Cirillo, Rocco; Schwarz, Matthias K; Rommel, Christian

2005-09-01

Phosphoinositide 3-kinases (PI3K) have long been considered promising drug targets for the treatment of inflammatory and autoimmune disorders as well as cancer and cardiovascular diseases. But the lack of specificity, isoform selectivity and poor biopharmaceutical profile of PI3K inhibitors have so far hampered rigorous disease-relevant target validation. Here we describe the identification and development of specific, selective and orally active small-molecule inhibitors of PI3Kgamma (encoded by Pik3cg). We show that Pik3cg(-/-) mice are largely protected in mouse models of rheumatoid arthritis; this protection correlates with defective neutrophil migration, further validating PI3Kgamma as a therapeutic target. We also describe that oral treatment with a PI3Kgamma inhibitor suppresses the progression of joint inflammation and damage in two distinct mouse models of rheumatoid arthritis, reproducing the protective effects shown by Pik3cg(-/-) mice. Our results identify selective PI3Kgamma inhibitors as potential therapeutic molecules for the treatment of chronic inflammatory disorders such as rheumatoid arthritis.

Histone deacetylase inhibition rescues structural and functional brain deficits in a mouse model of Kabuki syndrome

Science.gov (United States)

Bjornsson, Hans T.; Benjamin, Joel S.; Zhang, Li; Weissman, Jacqueline; Gerber, Elizabeth E.; Chen, Yi-Chun; Vaurio, Rebecca G.; Potter, Michelle C.; Hansen, Kasper D.; Dietz, Harry C.

2015-01-01

Kabuki syndrome is caused by haploinsufficiency for either of two genes that promote the opening of chromatin. If an imbalance between open and closed chromatin is central to the pathogenesis of Kabuki syndrome, agents that promote chromatin opening might have therapeutic potential. We have characterized a mouse model of Kabuki syndrome with a heterozygous deletion in the gene encoding the lysine-specific methyltransferase 2D (Kmt2d), leading to impairment of methyltransferase function. In vitro reporter alleles demonstrated a reduction in histone 4 acetylation and histone 3 lysine 4 trimethylation (H3K4me3) activity in mouse embryonic fibroblasts from Kmt2d+/βGeo mice. These activities were normalized in response to AR-42, a histone deacetylase inhibitor. In vivo, deficiency of H3K4me3 in the dentate gyrus granule cell layer of Kmt2d+/βGeo mice correlated with reduced neurogenesis and hippocampal memory defects. These abnormalities improved upon postnatal treatment with AR-42. Our work suggests that a reversible deficiency in postnatal neurogenesis underlies intellectual disability in Kabuki syndrome. PMID:25273096

Assessment of plasminogen synthesis in vitro by mouse tumor cells using a competition radioimmunoassay for mouse plasminogen

International Nuclear Information System (INIS)

Roblin, R.O.; Bell, T.E.; Young, P.L.

1978-01-01

A sensitive, specific competition radioimmunoassay for mouse plasmin(ogen) has been developed in order to determine whether mouse tumor cells can synthesize plasminogen in vitro. The rabbit anti-BALB/c mouse plasminogen antibodies used in the assay react with the plasminogen present in serum from BALB/c, C3H, AKR and C57BL/6 mice, and also recognized mouse plasmin. The competition radiommunoassay can detect as little as 50 ng of mouse plasminogen. No competition was observed with preparations of fetal calf, human and rabbit plasminogens. A variety of virus-transformed and mouse tumor cell lines were all found to contain less than 100 ng mouse plasminogen/mg of cell extract protein. Thus, if the plasminogen activator/plasmin system is important in the growth or movement of this group of tumor cells, the cells will be dependent upon the circulatory system of the host for their plasminogen supply. (Auth.)

A proposed defect tracking model for classifying the inserted defect reports to enhance software quality control.

Science.gov (United States)

Sultan, Torky; Khedr, Ayman E; Sayed, Mostafa

2013-01-01

NONE DECLARED Defect tracking systems play an important role in the software development organizations as they can store historical information about defects. There are many research in defect tracking models and systems to enhance their capabilities to be more specifically tracking, and were adopted with new technology. Furthermore, there are different studies in classifying bugs in a step by step method to have clear perception and applicable method in detecting such bugs. This paper shows a new proposed defect tracking model for the purpose of classifying the inserted defects reports in a step by step method for more enhancement of the software quality.

Implications of defect clusters formed in cascades on free defect generation and microstructural development

International Nuclear Information System (INIS)

Wiedersich, H.

1992-12-01

A large fraction of the defects produced by irradiation with energetic neutrons or heavy ions originates in cascades. Not only increased recombination of vacancy and interstitial defects but also significant clustering of like defects occur. Both processes reduce the number of point defects available for long range migration. Consequences of defect clustering in cascades will be discussed in a semi-quantitative form with the aid of calculations using a very simplified model: Quasi-steady-state distributions of immobile vacancy and/or interstitial clusters develop which, in turn, can become significant sinks for mobile defects, and, therefore reduce their lifetime. Although cluster sinks will cause segregation and, potentially, precipitation of second phases due to local changes of composition, the finite lifetime of clusters will not lead to lasting, local compositional changes. A transition from highly dense interstitial and vacancy cluster distributions to the void swelling regime occurs when the thermal evaporation of vacancies from small vacancy clusters becomes significant at higher temperatures. Unequal clustering of vacancies and interstitials leads to an imbalance of their fluxes of in the matrix and, hence, to unequal contributions to atom transport by interstitials and by vacancies even in the quasi-steady state approximation

Characterization of point defects in monolayer arsenene

Science.gov (United States)

Liang, Xiongyi; Ng, Siu-Pang; Ding, Ning; Wu, Chi-Man Lawrence

2018-06-01

Topological defects that are inevitably found in 2D materials can dramatically affect their properties. Using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) method, the structural, thermodynamic, electronic and magnetic properties of six types of typical point defects in arsenene, i.e. the Stone-Wales defect, single and double vacancies and adatoms, were systemically studied. It was found that these defects were all more easily generated in arsenene with lower formation energies than those with graphene and silicene. Stone-Wales defects can be transformed from pristine arsenene by overcoming a barrier of 2.19 eV and single vacancy defects tend to coalesce into double vacancy defects by diffusion. However, a type of adatom defect does not exhibit kinetic stability at room temperature. In addition, SV defects and another type of adatom defect can remarkably affect the electronic and magnetic properties of arsenene, e.g. they can introduce localized states near the Fermi level, as well as a strongly local magnetic moment due to dangling bond and unpaired electron. Furthermore, the simulated scanning tunneling microscopy (STM) and Raman spectroscopy were computed and the types of point defects can be fully characterized by correlating the STM images and Raman spectra to the defective atomistic structures. The results provide significant insights to the effect of defects in arsenene for potential applications, as well as identifications of two helpful tools (STM and Raman spectroscopy) to distinguish the type of defects in arsenene for future experiments.

Golga5 is dispensable for mouse embryonic development and postnatal survival.

Science.gov (United States)

McGee, Lynessa J; Jiang, Alex L; Lan, Yu

2017-07-01

Golgins are a family of coiled-coil proteins located at the cytoplasmic surface of the Golgi apparatus and have been implicated in maintaining Golgi structural integrity through acting as tethering factors for retrograde vesicle transport. Whereas knockdown of several individual golgins in cultured cells caused Golgi fragmentation and disruption of vesicle trafficking, analysis of mutant mouse models lacking individual golgins have discovered tissue-specific developmental functions. Recently, homozygous loss of function of GOLGA2, of which previous in vitro studies suggested an essential role in maintenance of Golgi structure and in mitosis, has been associated with a neuromuscular disorder in human patients, which highlights the need for understanding the developmental roles of the golgins in vivo. We report here generation of Golga5-deficient mice using CRISPR/Cas9-mediated genome editing. Although knockdown studies in cultured cells have implicated Golga5 in maintenance of Golgi organization, we show that Golga5 is not required for mouse embryonic development, postnatal survival, or fertility. Moreover, whereas Golga5 is structurally closely related to Golgb1, we show that inactivation of Golga5 does not enhance the severity of developmental defects in Golgb1-deficient mice. The Golga5-deficient mice enable further investigation of the roles and functional specificity of golgins in development and diseases. © 2017 Wiley Periodicals, Inc.

Beating Birth Defects

Centers for Disease Control (CDC) Podcasts

Each year in the U.S., one in 33 babies is affected by a major birth defect. Women can greatly improve their chances of giving birth to a healthy baby by avoiding some of the risk factors for birth defects before and during pregnancy. In this podcast, Dr. Stuart Shapira discusses ways to improve the chances of giving birth to a healthy baby.

Protective effects of positive lysosomal modulation in Alzheimer's disease transgenic mouse models.

Science.gov (United States)

Butler, David; Hwang, Jeannie; Estick, Candice; Nishiyama, Akiko; Kumar, Saranya Santhosh; Baveghems, Clive; Young-Oxendine, Hollie B; Wisniewski, Meagan L; Charalambides, Ana; Bahr, Ben A

2011-01-01

Alzheimer's disease (AD) is an age-related neurodegenerative pathology in which defects in proteolytic clearance of amyloid β peptide (Aβ) likely contribute to the progressive nature of the disorder. Lysosomal proteases of the cathepsin family exhibit up-regulation in response to accumulating proteins including Aβ(1-42). Here, the lysosomal modulator Z-Phe-Ala-diazomethylketone (PADK) was used to test whether proteolytic activity can be enhanced to reduce the accumulation events in AD mouse models expressing different levels of Aβ pathology. Systemic PADK injections in APP(SwInd) and APPswe/PS1ΔE9 mice caused 3- to 8-fold increases in cathepsin B protein levels and 3- to 10-fold increases in the enzyme's activity in lysosomal fractions, while neprilysin and insulin-degrading enzyme remained unchanged. Biochemical analyses indicated the modulation predominantly targeted the active mature forms of cathepsin B and markedly changed Rab proteins but not LAMP1, suggesting the involvement of enhanced trafficking. The modulated lysosomal system led to reductions in both Aβ immunostaining as well as Aβ(x-42) sandwich ELISA measures in APP(SwInd) mice of 10-11 months. More extensive Aβ deposition in 20-22-month APPswe/PS1ΔE9 mice was also reduced by PADK. Selective ELISAs found that a corresponding production of the less pathogenic Aβ(1-38) occurs as Aβ(1-42) levels decrease in the mouse models, indicating that PADK treatment leads to Aβ truncation. Associated with Aβ clearance was the elimination of behavioral and synaptic protein deficits evident in the two transgenic models. These findings indicate that pharmacologically-controlled lysosomal modulation reduces Aβ(1-42) accumulation, possibly through intracellular truncation that also influences extracellular deposition, and in turn offsets the defects in synaptic composition and cognitive functions. The selective modulation promotes clearance at different levels of Aβ pathology and provides proof

Toward Intelligent Software Defect Detection

Science.gov (United States)

Benson, Markland J.

2011-01-01

Source code level software defect detection has gone from state of the art to a software engineering best practice. Automated code analysis tools streamline many of the aspects of formal code inspections but have the drawback of being difficult to construct and either prone to false positives or severely limited in the set of defects that can be detected. Machine learning technology provides the promise of learning software defects by example, easing construction of detectors and broadening the range of defects that can be found. Pinpointing software defects with the same level of granularity as prominent source code analysis tools distinguishes this research from past efforts, which focused on analyzing software engineering metrics data with granularity limited to that of a particular function rather than a line of code.

Thyroid Medication Use and Birth Defects in the National Birth Defects Prevention Study.

Science.gov (United States)

Howley, Meredith M; Fisher, Sarah C; Van Zutphen, Alissa R; Waller, Dorothy K; Carmichael, Suzan L; Browne, Marilyn L

2017-11-01

Thyroid disorders are common among reproductive-aged women, with hypothyroidism affecting 2 to 3% of pregnancies, and hyperthyroidism affecting an additional 0.1 to 1%. We examined associations between thyroid medications and individual birth defects using data from the National Birth Defects Prevention Study (NBDPS). The NBDPS is a multisite, population-based, case-control study that included pregnancies with estimated delivery dates from 1997 to 2011. We analyzed self-reported thyroid medication use from mothers of 31,409 birth defect cases and 11,536 unaffected controls. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression for birth defects with five or more exposed cases, controlling for maternal age, race/ethnicity, and study center. Crude ORs and exact 95% CIs were estimated for defects with 3 to 4 exposed cases. Thyroid hormone was used by 738 (2.3%) case and 237 (2.1%) control mothers, and was associated with anencephaly (OR = 1.68; 95% CI, 1.03-2.73), holoprosencephaly (OR = 2.48; 95% CI, 1.13-5.44), hydrocephaly (1.77; 95% CI, 1.07-2.95) and small intestinal atresia (OR = 1.81; 95% CI, 1.04-3.15). Anti-thyroid medication was used by 34 (0.1%) case and 10 (<0.1%) control mothers, and was associated with aortic valve stenosis (OR = 6.91; 95% CI, 1.21-27.0). While new associations were identified, our findings are relatively consistent with previous NBDPS analyses. Our findings suggest thyroid medication use is not associated with most birth defects studied in the NBDPS, but may be associated with some specific birth defects. These results should not be interpreted to suggest that medications used to treat thyroid disease are teratogens, as the observed associations may reflect effects of the underlying thyroid disease. Birth Defects Research 109:1471-1481, 2017.© 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

The Mouse Tumor Biology Database: A Comprehensive Resource for Mouse Models of Human Cancer.

Science.gov (United States)

Krupke, Debra M; Begley, Dale A; Sundberg, John P; Richardson, Joel E; Neuhauser, Steven B; Bult, Carol J

2017-11-01

Research using laboratory mice has led to fundamental insights into the molecular genetic processes that govern cancer initiation, progression, and treatment response. Although thousands of scientific articles have been published about mouse models of human cancer, collating information and data for a specific model is hampered by the fact that many authors do not adhere to existing annotation standards when describing models. The interpretation of experimental results in mouse models can also be confounded when researchers do not factor in the effect of genetic background on tumor biology. The Mouse Tumor Biology (MTB) database is an expertly curated, comprehensive compendium of mouse models of human cancer. Through the enforcement of nomenclature and related annotation standards, MTB supports aggregation of data about a cancer model from diverse sources and assessment of how genetic background of a mouse strain influences the biological properties of a specific tumor type and model utility. Cancer Res; 77(21); e67-70. ©2017 AACR . ©2017 American Association for Cancer Research.

Rescue of cell death and inflammation of a mouse model of complex 1-mediated vision loss by repurposed drug molecules.

Science.gov (United States)

Yu, Alfred K; Datta, Sandipan; McMackin, Marissa Z; Cortopassi, Gino A

2017-12-15

Inherited mitochondrial optic neuropathies, such as Leber's hereditary optic neuropathy (LHON) and Autosomal dominant optic atrophy (ADOA) are caused by mutant mitochondrial proteins that lead to defects in mitochondrial complex 1-driven ATP synthesis, and cause specific retinal ganglion cell (RGC) loss. Complex 1 defects also occur in patients with primary open angle glaucoma (POAG), in which there is specific RGC loss. The treatment of mitochondrial optic neuropathy in the US is only supportive. The Ndufs4 knockout (Ndufs4 KO) mouse is a mitochondrial complex 1-deficient model that leads to RGC loss and rapid vision loss and allows for streamlined testing of potential therapeutics. Preceding RGC loss in the Ndufs4 KO is the loss of starburst amacrine cells, which may be an important target in the mechanism of complex 1-deficient vision loss. Papaverine and zolpidem were recently shown to be protective of bioenergetic loss in cell models of optic neuropathy. Treatment of Ndufs4 KO mice with papaverine, zolpidem, and rapamycin-suppressed inflammation, prevented cell death, and protected from vision loss. Thus, in the Ndufs4 KO mouse model of mitochondrial optic neuropathy, papaverine and zolpidem provided significant protection from multiple pathophysiological features, and as approved drugs in wide human use could be considered for the novel indication of human optic neuropathy. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Embedded defects

International Nuclear Information System (INIS)

Barriola, M.; Vachaspati, T.; Bucher, M.

1994-01-01

We give a prescription for embedding classical solutions and, in particular, topological defects in field theories which are invariant under symmetry groups that are not necessarily simple. After providing examples of embedded defects in field theories based on simple groups, we consider the electroweak model and show that it contains the Z string and a one-parameter family of strings called the W(α) string. It is argued that although the members of this family are gauge equivalent when considered in isolation, each member becomes physically distinct when multistring configurations are considered. We then turn to the issue of stability of embedded defects and demonstrate the instability of a large class of such solutions in the absence of bound states or condensates. The Z string is shown to be unstable for all values of the Higgs boson mass when θ W =π/4. W strings are also shown to be unstable for a large range of parameters. Embedded monopoles suffer from the Brandt-Neri-Coleman instability. Finally, we connect the electroweak string solutions to the sphaleron

Study of residue type defect formation mechanism and the effect of advanced defect reduction (ADR) rinse process

Science.gov (United States)

Arima, Hiroshi; Yoshida, Yuichi; Yoshihara, Kosuke; Shibata, Tsuyoshi; Kushida, Yuki; Nakagawa, Hiroki; Nishimura, Yukio; Yamaguchi, Yoshikazu

2009-03-01

Residue type defect is one of yield detractors in lithography process. It is known that occurrence of the residue type defect is dependent on resist development process and the defect is reduced by optimized rinsing condition. However, the defect formation is affected by resist materials and substrate conditions. Therefore, it is necessary to optimize the development process condition by each mask level. Those optimization steps require a large amount of time and effort. The formation mechanism is investigated from viewpoint of both material and process. The defect formation is affected by resist material types, substrate condition and development process condition (D.I.W. rinse step). Optimized resist formulation and new rinse technology significantly reduce the residue type defect.

Progesterone Prevents High-Grade Serous Ovarian Cancer by Inducing Necroptosis of p53-Defective Fallopian Tube Epithelial Cells

Directory of Open Access Journals (Sweden)

Na-Yiyuan Wu

2017-03-01

Full Text Available High-grade serous ovarian carcinoma (HGSOC originates mainly from the fallopian tube (FT epithelium and always carries early TP53 mutations. We previously reported that tumors initiate in the FT fimbria epithelium because of apoptotic failure and the expansion of cells with DNA double-strand breaks (DSB caused by bathing of the FT epithelial cells in reactive oxygen species (ROSs and hemoglobin-rich follicular fluid (FF after ovulation. Because ovulation is frequent and HGSOC is rare, we hypothesized that luteal-phase progesterone (P4 could eliminate p53-defective FT cells. Here we show that P4, via P4 receptors (PRs, induces necroptosis in Trp53−/− mouse oviduct epithelium and in immortalized human p53-defective fimbrial epithelium through the TNF-α/RIPK1/RIPK3/MLKL pathway. Necroptosis occurs specifically at diestrus, recovers at the proestrus phase of the estrus cycle, and can be augmented with P4 supplementation. These results reveal the mechanism of the well-known ability of progesterone to prevent ovarian cancer.

Strained interface defects in silicon nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Lee, Benjamin G.; Stradins, Paul [National Center for Photovoltaics, National Renewable Energy Laboratory, Golden, CO (United States); Hiller, Daniel; Zacharias, Margit [IMTEK - Faculty of Engineering, Albert-Ludwigs-University Freiburg (Germany); Luo, Jun-Wei; Beard, Matthew C. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Semonin, Octavi E. [Chemical and Materials Science, National Renewable Energy Laboratory, Golden, CO (United States); Department of Physics, University of Colorado, Boulder, CO (United States)

2012-08-07

The surface of silicon nanocrystals embedded in an oxide matrix can contain numerous interface defects. These defects strongly affect the nanocrystals' photoluminescence efficiency and optical absorption. Dangling-bond defects are nearly eliminated by H{sub 2} passivation, thus decreasing absorption below the quantum-confined bandgap and enhancing PL efficiency by an order of magnitude. However, there remain numerous other defects seen in absorption by photothermal deflection spectroscopy; these defects cause non-radiative recombination that limits the PL efficiency to <15%. Using atomistic pseudopotential simulations, we attribute these defects to two specific types of distorted bonds: Si-Si and bridging Si-O-Si bonds between two Si atoms at the nanocrystal surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Lack of centrioles and primary cilia in STIL(-/-) mouse embryos.

Science.gov (United States)

David, Ahuvit; Liu, Fengying; Tibelius, Alexandra; Vulprecht, Julia; Wald, Diana; Rothermel, Ulrike; Ohana, Reut; Seitel, Alexander; Metzger, Jasmin; Ashery-Padan, Ruth; Meinzer, Hans-Peter; Gröne, Hermann-Josef; Izraeli, Shai; Krämer, Alwin

2014-01-01

Although most animal cells contain centrosomes, consisting of a pair of centrioles, their precise contribution to cell division and embryonic development is unclear. Genetic ablation of STIL, an essential component of the centriole replication machinery in mammalian cells, causes embryonic lethality in mice around mid gestation associated with defective Hedgehog signaling. Here, we describe, by focused ion beam scanning electron microscopy, that STIL(-/-) mouse embryos do not contain centrioles or primary cilia, suggesting that these organelles are not essential for mammalian development until mid gestation. We further show that the lack of primary cilia explains the absence of Hedgehog signaling in STIL(-/-) cells. Exogenous re-expression of STIL or STIL microcephaly mutants compatible with human survival, induced non-templated, de novo generation of centrioles in STIL(-/-) cells. Thus, while the abscence of centrioles is compatible with mammalian gastrulation, lack of centrioles and primary cilia impairs Hedgehog signaling and further embryonic development.

Dendritic spine pathology in autism: lessons learned from mouse models

Institute of Scientific and Technical Information of China (English)

Qiangge Zhang; Dingxi Zhou; Guoping Feng

2016-01-01

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders that affect up to 1.5% of population in the world. Recent large scale genomic studies show that genetic causes of ASD are very heterogeneous. Gene ontology, pathway analysis and animal model studies have revealed several potential converging mechanisms including postsynaptic dysfunction of excitatory synapses. In this review, we focus on the structural and functional specializations of dendritic spines, and describe their defects in ASD. We use Fragile X syndrome, Rett syndrome and Phe-lan-McDermid syndrome, three of the most studied neurodevelopmental disorders with autism features, as examples to demonstrate the significant contribution made by mouse models towards the understanding of monogenic ASD. We envision that the development and application of new technologies to study the function of dendritic spines in valid animal models will eventually lead to innovative treatments for ASD.

Novel Alternative Splice Variants of Mouse Cdk5rap2.

Directory of Open Access Journals (Sweden)

Nadine Kraemer

Full Text Available Autosomal recessive primary microcephaly (MCPH is a rare neurodevelopmental disorder characterized by a pronounced reduction of brain volume and intellectual disability. A current model for the microcephaly phenotype invokes a stem cell proliferation and differentiation defect, which has moved the disease into the spotlight of stem cell biology and neurodevelopmental science. Homozygous mutations of the Cyclin-dependent kinase-5 regulatory subunit-associated protein 2 gene CDK5RAP2 are one genetic cause of MCPH. To further characterize the pathomechanism underlying MCPH, we generated a conditional Cdk5rap2 LoxP/hCMV Cre mutant mouse. Further analysis, initiated on account of a lack of a microcephaly phenotype in these mutant mice, revealed the presence of previously unknown splice variants of the Cdk5rap2 gene that are at least in part accountable for the lack of microcephaly in the mice.

The phenotype of FancB-mutant mouse embryonic stem cells

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Moon; Ko, Jun Ho; Choi, Yong Jun; Hu Lingchuan [Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245 (United States); Hasty, Paul, E-mail: hastye@uthscsa.edu [Department of Molecular Medicine and Institute of Biotechnology, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, San Antonio, TX 78245 (United States)

2011-07-01

Fanconi anemia (FA) is a rare autosomal recessive disease characterized by bone marrow failure, developmental defects and cancer. There are multiple FA genes that enable the repair of interstrand crosslinks (ICLs) in coordination with a variety of other DNA repair pathways in a way that is poorly understood. Here we present the phenotype of mouse embryonic stem (ES) cells mutated for FancB. We found FancB-mutant cells exhibited reduced cellular proliferation, hypersensitivity to the crosslinking agent mitomycin C (MMC), increased spontaneous and MMC-induced chromosomal abnormalities, reduced spontaneous sister chromatid exchanges (SCEs), reduced gene targeting, reduced MMC-induced Rad51 foci and absent MMC-induced FancD2 foci. Since FancB is on the X chromosome and since ES cells are typically XY, FancB is an excellent target for an epistatic analysis to elucidate FA's role in ICL repair.

Craniotomy Frontal Bone Defect

African Journals Online (AJOL)

2018-03-01

Mar 1, 2018 ... Defect reconstruction and fixation of the graft: The defect of ... where all loose fragments of fractured frontal bone was removed via the ... Mandible. • Ilium. • Allograft ... pediatric patients owing to skull growth. Thus, autologous ...

Who named the quantum defect?

International Nuclear Information System (INIS)

Rau, A.R.P.; Inokuti, M.

1997-01-01

The notion of the quantum defect is important in atomic and molecular spectroscopy and also in unifying spectroscopy with collision theory. In the latter context, the quantum defect may be viewed as an ancestor of the phase shift. However, the origin of the term quantum defect does not seem to be explained in standard textbooks. It occurred in a 1921 paper by Schroedinger, preceding quantum mechanics, yet giving the correct meaning as an index of the short-range interactions with the core of an atom. The authors present the early history of the quantum-defect idea, and sketch its recent developments

A targeted sequencing panel identifies rare damaging variants in multiple genes in the cranial neural tube defect, anencephaly.

Science.gov (United States)

Ishida, M; Cullup, T; Boustred, C; James, C; Docker, J; English, C; Lench, N; Copp, A J; Moore, G E; Greene, N D E; Stanier, P

2018-04-01

Neural tube defects (NTDs) affecting the brain (anencephaly) are lethal before or at birth, whereas lower spinal defects (spina bifida) may lead to lifelong neurological handicap. Collectively, NTDs rank among the most common birth defects worldwide. This study focuses on anencephaly, which despite having a similar frequency to spina bifida and being the most common type of NTD observed in mouse models, has had more limited inclusion in genetic studies. A genetic influence is strongly implicated in determining risk of NTDs and a molecular diagnosis is of fundamental importance to families both in terms of understanding the origin of the condition and for managing future pregnancies. Here we used a custom panel of 191 NTD candidate genes to screen 90 patients with cranial NTDs (n = 85 anencephaly and n = 5 craniorachischisis) with a targeted exome sequencing platform. After filtering and comparing to our in-house control exome database (N = 509), we identified 397 rare variants (minor allele frequency, MAF < 1%), 21 of which were previously unreported and predicted damaging. This included 1 frameshift (PDGFRA), 2 stop-gained (MAT1A; NOS2) and 18 missense variations. Together with evidence for oligogenic inheritance, this study provides new information on the possible genetic causation of anencephaly. © 2017 The Authors. Clinical Genetics published by John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Defective pulmonary innate immune responses post-stem cell transplantation; review and results from one model system

Directory of Open Access Journals (Sweden)

Racquel eDomingo-Gonzalez

2013-05-01

Full Text Available Infectious pulmonary complications limit the success of hematopoietic stem cell transplantation (HSCT as a therapy for malignant and nonmalignant disorders. Susceptibility to pathogens in both autologous and allogeneic HSCT recipients persists despite successful immune reconstitution. As studying the causal effects of these immune defects in the human population can be limiting, a bone marrow transplant (BMT mouse model can be used to understand the defect in mounting a productive innate immune response post-transplantation. When syngeneic BMT is performed, this system allows the study of BMT-induced alterations in innate immune cell function that are independent of the confounding effects of immunosuppressive therapy and graft-versus-host disease. Studies from several laboratories, including our own show that pulmonary susceptibility to bacterial infections post-BMT are largely due to alterations in the lung alveolar macrophages. Changes in these cells post-BMT include cytokine and eicosanoid dysregulations, scavenger receptor alterations, changes in micro RNA profiles, and alterations in intracellular signaling molecules that limit bacterial phagocytosis and killing. The changes that occur highlight mechanisms that promote susceptibility to infections commonly afflicting HSCT recipients and provide insight into therapeutic targets that may improve patient outcomes post-HSCT.

Serine biosynthesis and transport defects.

Science.gov (United States)

El-Hattab, Ayman W

2016-07-01

l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

Glycine receptor mutants of the mouse: what are possible routes of inhibitory compensation?

Directory of Open Access Journals (Sweden)

Natascha eSchaefer

2012-10-01

Full Text Available Defects in glycinergic inhibition result in a complex neuromotor disorder in humans known as hyperekplexia (OMIM 149400 with similar phenotypes in rodents characterized by an exaggerated startle reflex and hypertonia. Analogous to genetic defects in humans, single point mutations, microdeletions, or insertions in the Glra1 gene but also in the Glrb gene underlie the pathology in mice. The mutations either localized in the α (spasmodic, oscillator, cincinnati, Nmf11 or the β (spastic subunit of the GlyR are much less tolerated in mice than in humans, leaving the question for the existence of different regulatory elements of the pathomechanisms in humans and rodents. In addition to the spontaneous mutations, new insights into understanding of the regulatory pathways in hyperekplexia or glycine encephalopathy arose from the constantly increasing number of knock-out as well as knock-in mutants of GlyRs. Over the last five years, various efforts using in vivo whole cell recordings provided a detailed analysis of the kinetic parameters underlying glycinergic dysfunction. Presynaptic compensation as well as postsynaptic compensatory mechanisms in these mice by other GlyR subunits or GABAA receptors, and the role of extra-synaptic GlyRs is still a matter of debate. A recent study on the mouse mutant oscillator, displayed a novel aspect for compensation of functionality by complementation of receptor domains that fold independently. This review focuses on defects in glycinergic neurotransmission in mice discussed with the background of human hyperekplexia en route to strategies of compensation.

A mouse model for Costello syndrome reveals an Ang II–mediated hypertensive condition

Science.gov (United States)

Schuhmacher, Alberto J.; Guerra, Carmen; Sauzeau, Vincent; Cañamero, Marta; Bustelo, Xosé R.; Barbacid, Mariano

2008-01-01

Germline activation of H-RAS oncogenes is the primary cause of Costello syndrome (CS), a neuro-cardio-facio-cutaneous developmental syndrome. Here we describe the generation of a mouse model of CS by introduction of an oncogenic Gly12Val mutation in the mouse H-Ras locus using homologous recombination in ES cells. Germline expression of the endogenous H-RasG12V oncogene, even in homozygosis, resulted in hyperplasia of the mammary gland. However, development of tumors in these mice was rare. H-RasG12V mutant mice closely phenocopied some of the abnormalities observed in patients with CS, including facial dysmorphia and cardiomyopathies. These mice also displayed alterations in the homeostasis of the cardiovascular system, including development of systemic hypertension, extensive vascular remodeling, and fibrosis in both the heart and the kidneys. This phenotype was age dependent and was a consequence of the abnormal upregulation of the renin–Ang II system. Treatment with captopril, an inhibitor of Ang II biosynthesis, prevented development of the hypertension condition, vascular remodeling, and heart and kidney fibrosis. In addition, it partially alleviated the observed cardiomyopathies. These mice should help in elucidating the etiology of CS symptoms, identifying additional defects, and evaluating potential therapeutic strategies. PMID:18483625

Local delivery of FTY720 accelerates cranial allograft incorporation and bone formation.

Science.gov (United States)

Huang, Cynthia; Das, Anusuya; Barker, Daniel; Tholpady, Sunil; Wang, Tiffany; Cui, Quanjun; Ogle, Roy; Botchwey, Edward

2012-03-01

Endogenous stem cell recruitment to the site of skeletal injury is key to enhanced osseous remodeling and neovascularization. To this end, this study utilized a novel bone allograft coating of poly(lactic-co-glycolic acid) (PLAGA) to sustain the release of FTY720, a selective agonist for sphingosine 1-phosphate (S1P) receptors, from calvarial allografts. Uncoated allografts, vehicle-coated, low dose FTY720 in PLAGA (1:200 w:w) and high dose FTY720 in PLAGA (1:40) were implanted into critical size calvarial bone defects. The ability of local FTY720 delivery to promote angiogenesis, maximize osteoinductivity and improve allograft incorporation by recruitment of bone progenitor cells from surrounding soft tissues and microcirculation was evaluated. FTY720 bioactivity after encapsulation and release was confirmed with sphingosine kinase 2 assays. HPLC-MS quantified about 50% loaded FTY720 release of the total encapsulated drug (4.5 μg) after 5 days. Following 2 weeks of defect healing, FTY720 delivery led to statistically significant increases in bone volumes compared to controls, with total bone volume increases for uncoated, coated, low FTY720 and high FTY720 of 5.98, 3.38, 7.2 and 8.9 mm(3), respectively. The rate and extent of enhanced bone growth persisted through week 4 but, by week 8, increases in bone formation in FTY720 groups were no longer statistically significant. However, micro-computed tomography (microCT) of contrast enhanced vascular ingrowth (MICROFIL®) and histological analysis showed enhanced integration as well as directed bone growth in both high and low dose FTY720 groups compared to controls.

The Mouse That Soared

Science.gov (United States)

2004-09-01

Astronomers have used an X-ray image to make the first detailed study of the behavior of high-energy particles around a fast moving pulsar. The image, from NASA's Chandra X-ray Observatory, shows the shock wave created as a pulsar plows supersonically through interstellar space. These results will provide insight into theories for the production of powerful winds of matter and antimatter by pulsars. Chandra's image of the glowing cloud, known as the Mouse, shows a stubby bright column of high-energy particles, about four light years in length, swept back by the pulsar's interaction with interstellar gas. The intense source at the head of the X-ray column is the pulsar, estimated to be moving through space at about 1.3 million miles per hour. VLA Radio Image of the Mouse, Full Field VLA Radio Image of the Mouse, Full Field A cone-shaped cloud of radio-wave-emitting particles envelopes the X-ray column. The Mouse, a.k.a. G359.23-0.82, was discovered in 1987 by radio astronomers using the National Science Foundation's Very Large Array in New Mexico. It gets its name from its appearance in radio images that show a compact snout, a bulbous body, and a remarkable long, narrow, tail that extends for about 55 light years. "A few dozen pulsar wind nebulae are known, including the spectacular Crab Nebula, but none have the Mouse's combination of relatively young age and incredibly rapid motion through interstellar space," said Bryan Gaensler of the Harvard-Smithsonian Center for Astrophysics and lead author of a paper on the Mouse that will appear in an upcoming issue of The Astrophysical Journal. "We effectively are seeing a supersonic cosmic wind tunnel, in which we can study the effects of a pulsar's motion on its pulsar wind nebula, and test current theories." Illustration of the Mouse System Illustration of the Mouse System Pulsars are known to be rapidly spinning, highly magnetized neutron stars -- objects so dense that a mass equal to that of the Sun is packed into a

Paternal occupation and birth defects: findings from the National Birth Defects Prevention Study.

NARCIS (Netherlands)

Desrosiers, T.A.; Herring, A.H.; Shapira, S.K.; Hooiveld, M.; Luben, T.J.; Herdt-Losavio, M.L.; Lin, S.; Olshan, A.F.

2012-01-01

Objectives: Several epidemiological studies have suggested that certain paternal occupations may be associated with an increased prevalence of birth defects in offspring. Using data from the National Birth Defects Prevention Study, the authors investigated the association between paternal occupation

[Inconformity between soft tissue defect and bony defect in incomplete cleft palate].

Science.gov (United States)

Zhou, Xia; Ma, Lian

2014-12-01

To evaluate the inconformity between soft tissue defect and bony defect by observing the cleft extent of palate with complete secondary palate bony cleft in incomplete cleft palate patient. The patients with incomplete cleft palate treated in Hospital of Stomatology Peking University from July 2012 to June 2013 were reviewed, of which 75 cases with complete secondary palate bony cleft were selected in this study. The CT scan and intraoral photograph were taken before operation. The patients were classified as four types according to the extent of soft tissue defect. Type 1: soft tissue defect reached incisive foremen region, Type 2 was hard and soft cleft palate, Type 3 soft cleft palate and Type 4 submucous cleft palate. Type 1 was defined as conformity group (CG). The other three types were defined as inconformity group (ICG) and divided into three subgroups (ICG-I), (ICG-II) and (ICG-III). Fifty-seven patients were in ICG group, and the rate of inconformity was 76% (57/75). The percentage of ICG-I, ICG-II and ICG-III was 47% (27/57), 23% (13/57) and 30% (17/57), respevtively. There are different types of soft tissue deformity with complete secondary palate bony cleft. The inconformity between soft tissue and hard tissue defect exits in 3/4 of isolated cleft palate patients.

Early transcriptional responses of internalization defective Brucella abortus mutants in professional phagocytes, RAW 264.7.

Science.gov (United States)

Cha, Seung Bin; Lee, Won Jung; Shin, Min Kyoung; Jung, Myung Hwan; Shin, Seung Won; Yoo, An Na; Kim, Jong Wan; Yoo, Han Sang

2013-06-27

Brucella abortus is an intracellular zoonotic pathogen which causes undulant fever, endocarditis, arthritis and osteomyelitis in human and abortion and infertility in cattle. This bacterium is able to invade and replicate in host macrophage instead of getting removed by this defense mechanism. Therefore, understanding the interaction between virulence of the bacteria and the host cell is important to control brucellosis. Previously, we generated internalization defective mutants and analyzed the envelope proteins. The present study was undertaken to evaluate the changes in early transcriptional responses between wild type and internalization defective mutants infected mouse macrophage, RAW 264.7. Both of the wild type and mutant infected macrophages showed increased expression levels in proinflammatory cytokines, chemokines, apoptosis and G-protein coupled receptors (Gpr84, Gpr109a and Adora2b) while the genes related with small GTPase which mediate intracellular trafficking was decreased. Moreover, cytohesin 1 interacting protein (Cytip) and genes related to ubiquitination (Arrdc3 and Fbxo21) were down-regulated, suggesting the survival strategy of this bacterium. However, we could not detect any significant changes in the mutant infected groups compared to the wild type infected group. In summary, it was very difficult to clarify the alterations in host cellular transcription in response to infection with internalization defective mutants. However, we found several novel gene changes related to the GPCR system, ubiquitin-proteosome system, and growth arrest and DNA damages in response to B. abortus infection. These findings may contribute to a better understanding of the molecular mechanisms underlying host-pathogen interactions and need to be studied further.

Chemical characterisation of non-defective and defective green arabica and robusta coffees by electrospray ionization-mass spectrometry (ESI-MS).

Science.gov (United States)

Mendonça, Juliana C F; Franca, Adriana S; Oliveira, Leandro S; Nunes, Marcella

2008-11-15

The coffee roasted in Brazil is considered to be of low quality, due to the presence of defective coffee beans that depreciate the beverage quality. These beans, although being separated from the non-defective ones prior to roasting, are still commercialized in the coffee trading market. Thus, it was the aim of this work to verify the feasibility of employing ESI-MS to identify chemical characteristics that will allow the discrimination of Arabica and Robusta species and also of defective and non-defective coffees. Aqueous extracts of green (raw) defective and non-defective coffee beans were analyzed by direct infusion electrospray ionization mass spectrometry (ESI-MS) and this technique provided characteristic fingerprinting mass spectra that not only allowed for discrimination of species but also between defective and non-defective coffee beans. ESI-MS profiles in the positive mode (ESI(+)-MS) provided separation between defective and non-defective coffees within a given species, whereas ESI-MS profiles in the negative mode (ESI(-)-MS) provided separation between Arabica and Robusta coffees. Copyright © 2008 Elsevier Ltd. All rights reserved.

Topological defects from the multiverse

Science.gov (United States)

Zhang, Jun; Blanco-Pillado, Jose J.; Garriga, Jaume; Vilenkin, Alexander

2015-05-01

Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble.

Topological defects from the multiverse

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jun [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Blanco-Pillado, Jose J. [Department of Theoretical Physics, University of the Basque Country UPV/EHU, 48080 Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, 48013, Bilbao (Spain); Garriga, Jaume [Departament de Fisica Fonamental i Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti i Franques, 1, 08028, Barcelona (Spain); Vilenkin, Alexander [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)

2015-05-28

Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble.

Topological defects from the multiverse

International Nuclear Information System (INIS)

Zhang, Jun; Vilenkin, Alexander; Blanco-Pillado, Jose J.; Garriga, Jaume

2015-01-01

Many theories of the early universe predict the existence of a multiverse where bubbles continuously nucleate giving rise to observers in their interior. In this paper, we point out that topological defects of several dimensionalities will also be produced in de Sitter like regions of the multiverse. In particular, defects could be spontaneously nucleated in our parent vacuum. We study the evolution of these defects as they collide with and propagate inside of our bubble. We estimate the present distribution of defects in the observable part of the universe. The expected number of such nearby defects turns out to be quite small, even for the highest nucleation rate. We also study collisions of strings and domain walls with our bubble in our past light cone. We obtain simulated full-sky maps of the loci of such collisions, and find their angular size distribution. Similarly to what happens in the case of bubble collisions, the prospect of detecting any collisions of our bubble with ambient defects is greatly enhanced in the case where the cosmological constant of our parent vacuum is much higher than the vacuum energy density during inflation in our bubble

Burn mouse models

DEFF Research Database (Denmark)

Calum, Henrik; Høiby, Niels; Moser, Claus

2014-01-01

Severe thermal injury induces immunosuppression, involving all parts of the immune system, especially when large fractions of the total body surface area are affected. An animal model was established to characterize the burn-induced immunosuppression. In our novel mouse model a 6 % third-degree b......Severe thermal injury induces immunosuppression, involving all parts of the immune system, especially when large fractions of the total body surface area are affected. An animal model was established to characterize the burn-induced immunosuppression. In our novel mouse model a 6 % third...... with infected burn wound compared with the burn wound only group. The burn mouse model resembles the clinical situation and provides an opportunity to examine or develop new strategies like new antibiotics and immune therapy, in handling burn wound victims much....

A Transgenic Tri-Modality Reporter Mouse

OpenAIRE

Yan, Xinrui; Ray, Pritha; Paulmurugan, Ramasamy; Tong, Ricky; Gong, Yongquan; Sathirachinda, Ataya; Wu, Joseph C.; Gambhir, Sanjiv S.

2013-01-01

Transgenic mouse with a stably integrated reporter gene(s) can be a valuable resource for obtaining uniformly labeled stem cells, tissues, and organs for various applications. We have generated a transgenic mouse model that ubiquitously expresses a tri-fusion reporter gene (fluc2-tdTomato-ttk) driven by a constitutive chicken β-actin promoter. This "Tri-Modality Reporter Mouse" system allows one to isolate most cells from this donor mouse and image them for bioluminescent (fluc2), fluorescent...

Specific Disruption of Hippocampal Mossy Fiber Synapses in a Mouse Model of Familial Alzheimer's Disease

Science.gov (United States)

Wilke, Scott A.; Raam, Tara; Antonios, Joseph K.; Bushong, Eric A.; Koo, Edward H.; Ellisman, Mark H.; Ghosh, Anirvan

2014-01-01

The earliest stages of Alzheimer's disease (AD) are characterized by deficits in memory and cognition indicating hippocampal pathology. While it is now recognized that synapse dysfunction precedes the hallmark pathological findings of AD, it is unclear if specific hippocampal synapses are particularly vulnerable. Since the mossy fiber (MF) synapse between dentate gyrus (DG) and CA3 regions underlies critical functions disrupted in AD, we utilized serial block-face electron microscopy (SBEM) to analyze MF microcircuitry in a mouse model of familial Alzheimer's disease (FAD). FAD mutant MF terminal complexes were severely disrupted compared to control – they were smaller, contacted fewer postsynaptic spines and had greater numbers of presynaptic filopodial processes. Multi-headed CA3 dendritic spines in the FAD mutant condition were reduced in complexity and had significantly smaller sites of synaptic contact. Significantly, there was no change in the volume of classical dendritic spines at neighboring inputs to CA3 neurons suggesting input-specific defects in the early course of AD related pathology. These data indicate a specific vulnerability of the DG-CA3 network in AD pathogenesis and demonstrate the utility of SBEM to assess circuit specific alterations in mouse models of human disease. PMID:24454724

Metastable gravity on classical defects

International Nuclear Information System (INIS)

Ringeval, Christophe; Rombouts, Jan-Willem

2005-01-01

We discuss the realization of metastable gravity on classical defects in infinite-volume extra dimensions. In dilatonic Einstein gravity, it is found that the existence of metastable gravity on the defect core requires violation of the dominant energy condition for codimension N c =2 defects. This is illustrated with a detailed analysis of a six-dimensional hyperstring minimally coupled to dilaton gravity. We present the general conditions under which a codimension N c >2 defect admits metastable modes, and find that they differ from lower codimensional models in that, under certain conditions, they do not require violation of energy conditions to support quasilocalized gravity

Simulation based mask defect repair verification and disposition

Science.gov (United States)

Guo, Eric; Zhao, Shirley; Zhang, Skin; Qian, Sandy; Cheng, Guojie; Vikram, Abhishek; Li, Ling; Chen, Ye; Hsiang, Chingyun; Zhang, Gary; Su, Bo

2009-10-01

As the industry moves towards sub-65nm technology nodes, the mask inspection, with increased sensitivity and shrinking critical defect size, catches more and more nuisance and false defects. Increased defect counts pose great challenges in the post inspection defect classification and disposition: which defect is real defect, and among the real defects, which defect should be repaired and how to verify the post-repair defects. In this paper, we address the challenges in mask defect verification and disposition, in particular, in post repair defect verification by an efficient methodology, using SEM mask defect images, and optical inspection mask defects images (only for verification of phase and transmission related defects). We will demonstrate the flow using programmed mask defects in sub-65nm technology node design. In total 20 types of defects were designed including defects found in typical real circuit environments with 30 different sizes designed for each type. The SEM image was taken for each programmed defect after the test mask was made. Selected defects were repaired and SEM images from the test mask were taken again. Wafers were printed with the test mask before and after repair as defect printability references. A software tool SMDD-Simulation based Mask Defect Disposition-has been used in this study. The software is used to extract edges from the mask SEM images and convert them into polygons to save in GDSII format. Then, the converted polygons from the SEM images were filled with the correct tone to form mask patterns and were merged back into the original GDSII design file. This merge is for the purpose of contour simulation-since normally the SEM images cover only small area (~1 μm) and accurate simulation requires including larger area of optical proximity effect. With lithography process model, the resist contour of area of interest (AOI-the area surrounding a mask defect) can be simulated. If such complicated model is not available, a simple

Defects in new protective aprons

International Nuclear Information System (INIS)

Glaze, S.; LeBlanc, A.D.; Bushong, S.C.

1984-01-01

Upon careful examination, several defects have been detected in new protective aprons. The nature of the defects is identified and described. Although the occurrence of such defects has not exceeded 5%, they are significant enough to warrant return of the lead apron to the supplier. It is recommended that the integrity of all new protective aprons be verified upon receipt as well as at yearly intervals

Platelet rich fibrin in jaw defects

Science.gov (United States)

Nica, Diana; Ianes, Emilia; Pricop, Marius

2016-03-01

Platelet rich fibrin (PRF) is a tissue product of autologous origin abundant in growth factors, widely used in regenerative procedures. Aim of the study: Evaluation of the regenerative effect of PRF added in the bony defects (after tooth removal or after cystectomy) Material and methods: The comparative nonrandomized study included 22 patients divided into 2 groups. The first group (the test group) included 10 patients where the bony defects were treated without any harvesting material. The second group included 12 patients where the bony defects were filled with PRF. The bony defect design was not critical, with one to two walls missing. After the surgeries, a close clinically monitoring was carried out. The selected cases were investigated using both cone beam computer tomography (CBCT) and radiographic techniques after 10 weeks postoperatively. Results: Faster bone regeneration was observed in the bony defects filled with PRF comparing with the not grafted bony defects. Conclusions: PRF added in the bony defects accelerates the bone regeneration. This simplifies the surgical procedures and decreases the economic costs.

Type 2 diabetes mellitus induces congenital heart defects in murine embryos by increasing oxidative stress, endoplasmic reticulum stress, and apoptosis.

Science.gov (United States)

Wu, Yanqing; Reece, E Albert; Zhong, Jianxiang; Dong, Daoyin; Shen, Wei-Bin; Harman, Christopher R; Yang, Peixin

2016-09-01

Maternal type 1 and 2 diabetes mellitus are strongly associated with high rates of severe structural birth defects, including congenital heart defects. Studies in type 1 diabetic embryopathy animal models have demonstrated that cellular stress-induced apoptosis mediates the teratogenicity of maternal diabetes leading to congenital heart defect formation. However, the mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects remain largely unknown. We aim to determine whether oxidative stress, endoplasmic reticulum stress, and excessive apoptosis are the intracellular molecular mechanisms underlying maternal type 2 diabetes mellitus-induced congenital heart defects. A mouse model of maternal type 2 diabetes mellitus was established by feeding female mice a high-fat diet (60% fat). After 15 weeks on the high-fat diet, the mice showed characteristics of maternal type 2 diabetes mellitus. Control dams were either fed a normal diet (10% fat) or the high-fat diet during pregnancy only. Female mice from the high-fat diet group and the 2 control groups were mated with male mice that were fed a normal diet. At E12.5, embryonic hearts were harvested to determine the levels of lipid peroxides and superoxide, endoplasmic reticulum stress markers, cleaved caspase 3 and 8, and apoptosis. E17.5 embryonic hearts were harvested for the detection of congenital heart defect formation using India ink vessel patterning and histological examination. Maternal type 2 diabetes mellitus significantly induced ventricular septal defects and persistent truncus arteriosus in the developing heart, along with increasing oxidative stress markers, including superoxide and lipid peroxidation; endoplasmic reticulum stress markers, including protein levels of phosphorylated-protein kinase RNA-like endoplasmic reticulum kinase, phosphorylated-IRE1α, phosphorylated-eIF2α, C/EBP homologous protein, and binding immunoglobulin protein; endoplasmic reticulum chaperone gene

Little string origin of surface defects

Energy Technology Data Exchange (ETDEWEB)

Haouzi, Nathan; Schmid, Christian [Center for Theoretical Physics, University of California, Berkeley,LeConte Hall, Berkeley (United States)

2017-05-16

We derive a large class of codimension-two defects of 4d N=4 Super Yang-Mills (SYM) theory from the (2,0) little string. The origin of the little string is type IIB theory compactified on an ADE singularity. The defects are D-branes wrapping the 2-cycles of the singularity. We use this construction to make contact with the description of SYM defects due to Gukov and Witten https://arxiv.org/abs/hep-th/0612073. Furthermore, we provide a geometric perspective on the nilpotent orbit classification of codimension-two defects, and the connection to ADE-type Toda CFT. The only data needed to specify the defects is a set of weights of the algebra obeying certain constraints, which we give explicitly. We highlight the differences between the defect classification in the little string theory and its (2,0) CFT limit.

First-Principles Investigations of Defects in Minerals

Science.gov (United States)

Verma, Ashok K.

2011-07-01

The ideal crystal has an infinite 3-dimensional repetition of identical units which may be atoms or molecules. But real crystals are limited in size and they have disorder in stacking which as called defects. Basically three types of defects exist in solids: 1) point defects, 2) line defects, and 3) surface defects. Common point defects are vacant lattice sites, interstitial atoms and impurities and these are known to influence strongly many solid-state transport properties such as diffusion, electrical conduction, creep, etc. In thermal equilibrium point defects concentrations are determined by their formation enthalpies and their movement by their migration barriers. Line and surface defects are though absent from the ideal crystal in thermal equilibrium due to higher energy costs but they are invariably present in all real crystals. Line defects include edge-, screw- and mixed-dislocations and their presence is essential in explaining the mechanical strength and deformation of real crystals. Surface defects may arise at the boundary between two grains, or small crystals, within a larger crystal. A wide variety of grain boundaries can form in a polycrystal depending on factors such growth conditions and thermal treatment. In this talk we will present our first-principles density functional theory based defect studies of SiO2 polymorphs (stishovite, CaCl2-, α-PbO2-, and pyrite-type), Mg2SiO4 polymorphs (forsterite, wadsleyite and ringwoodite) and MgO [1-3]. Briefly, several native point defects including vacancies, interstitials, and their complexes were studied in silica polymorphs upto 200 GPa. Their values increase by a factor of 2 over the entire pressure range studied with large differences in some cases between different phases. The Schottky defects are energetically most favorable at zero pressure whereas O-Frenkel pairs become systematically more favorable at pressures higher than 20 GPa. The geometric and electronic structures of defects and migrating

Various Stone-Wales defects in phagraphene

Science.gov (United States)

Openov, L. A.; Podlivaev, A. I.

2016-08-01

Various Stone-Wales defects in phagraphene, which is a graphene allotrope, predicted recently are studied in terms of the nonorthogonal tight-binding model. The energies of the defect formation and the heights of energy barriers preventing the formation and annealing of the defects are found. Corresponding frequency factors in the Arrhenius formula are calculated. The evolution of the defect structure is studied in the real-time mode using the molecular dynamics method.

Inner ear morphology is perturbed in two novel mouse models of recessive deafness.

Directory of Open Access Journals (Sweden)

Kerry A Miller

Full Text Available Human MYO7A mutations can cause a variety of conditions involving the inner ear. These include dominant and recessive non-syndromic hearing loss and syndromic conditions such as Usher syndrome. Mouse models of deafness allow us to investigate functional pathways involved in normal and abnormal hearing processes. We present two novel mouse models with mutations in the Myo7a gene with distinct phenotypes. The mutation in Myo7a(I487N/I487N ewaso is located within the head motor domain of Myo7a. Mice exhibit a profound hearing loss and manifest behaviour associated with a vestibular defect. A mutation located in the linker region between the coiled-coil and the first MyTH4 domains of the protein is responsible in Myo7a(F947I/F947I dumbo. These mice show a less severe hearing loss than in Myo7a(I487N/I487N ewaso; their hearing loss threshold is elevated at 4 weeks old, and progressively worsens with age. These mice show no obvious signs of vestibular dysfunction, although scanning electron microscopy reveals a mild phenotype in vestibular stereocilia bundles. The Myo7a(F947I/F947I dumbo strain is therefore the first reported Myo7a mouse model without an overt vestibular phenotype; a possible model for human DFNB2 deafness. Understanding the molecular basis of these newly identified mutations will provide knowledge into the complex genetic pathways involved in the maintenance of hearing, and will provide insight into recessively inherited sensorineural hearing loss in humans.

Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration.

Science.gov (United States)

Aquino-Martínez, Rubén; Angelo, Alcira P; Pujol, Francesc Ventura

2017-11-16

Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC) recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca 2+ -containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO 4 ) on MSC migration. In addition, to evaluate the influence of CaSO 4 on MSC differentiation and the potential molecular mechanisms involved. A circular calvarial bone defect (5 mm diameter) was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO 4 concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO 4 effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO 4 treatment was also evaluated by qPCR. CaSO 4 increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO 4 significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO 4 -containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO 4 and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO 4 effects on MSC migration. Specific CaSO 4 concentrations induce bone regeneration of calvarial defects in part by acting on the host's undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO 4 regulates BMP-2-induced MSC migration by differentially activating the PI3

Quantum computing with defects.

Science.gov (United States)

Weber, J R; Koehl, W F; Varley, J B; Janotti, A; Buckley, B B; Van de Walle, C G; Awschalom, D D

2010-05-11

Identifying and designing physical systems for use as qubits, the basic units of quantum information, are critical steps in the development of a quantum computer. Among the possibilities in the solid state, a defect in diamond known as the nitrogen-vacancy (NV(-1)) center stands out for its robustness--its quantum state can be initialized, manipulated, and measured with high fidelity at room temperature. Here we describe how to systematically identify other deep center defects with similar quantum-mechanical properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate defect systems. To illustrate these points in detail, we compare electronic structure calculations of the NV(-1) center in diamond with those of several deep centers in 4H silicon carbide (SiC). We then discuss the proposed criteria for similar defects in other tetrahedrally coordinated semiconductors.

Preclinical evaluation of severely defective manganese-based nanocrystal as a liver-specific contrast media for MR imaging: comparison with Gd-EOB-DTPA and MnDPDP

Science.gov (United States)

Zhang, Yu; Xiao, Xiao-ping; Shu, Ting; Cai, Jing; Xiao, Xin-lan; Li, Yan-shu; Zhang, Zhong-wei; Tang, Qun

2018-06-01

Manganese-based (chemically formulated of KMnF3) nanocrystal was evaluated as a liver-specific contrast agent for MR imaging and its imaging performance was also compared with those of two commercial hepatobiliary contrast media (Gd-EOB-DTPA and MnDPDP). KMnF3 nanocrystal was post-treated using a plasma technique to cause severe defects, leading to appropriate water dispersibility and high relaxivity. Severely defective KMnF3 nanocrystal (SD-KMnF3) has characteristic high tolerance, as evidenced by cytotoxicity on the macrophage cell, and acute and subchronic toxicity on the healthy mouse. SD-KMnF3 showed better hepatic MR imaging as the T 1 relaxation time of the liver decreased to only 17% of the control group, compared to 22% of the control group for Gd-EOB-DTPA (P hepatocarcinoma or metastatic lesions.

Charged Semiconductor Defects Structure, Thermodynamics and Diffusion

CERN Document Server

Seebauer, Edmund G

2009-01-01

The technologically useful properties of a solid often depend upon the types and concentrations of the defects it contains. Not surprisingly, defects in semiconductors have been studied for many years, in many cases with a view towards controlling their behavior through various forms of "defect engineering." For example, in the bulk, charging significantly affects the total concentration of defects that are available to mediate phenomena such as solid-state diffusion. Surface defects play an important role in mediating surface mass transport during high temperature processing steps such as epitaxial film deposition, diffusional smoothing in reflow, and nanostructure formation in memory device fabrication. Charged Semiconductor Defects details the current state of knowledge regarding the properties of the ionized defects that can affect the behavior of advanced transistors, photo-active devices, catalysts, and sensors. Features: Group IV, III-V, and oxide semiconductors; Intrinsic and extrinsic defects; and, P...

Developmental defects and genomic instability after x-irradiation of wild-type and genetically modified mouse pre-implantation and early post-implantation embryos

International Nuclear Information System (INIS)

Jacquet, P

2012-01-01

Results obtained from the end of the 1950s suggested that ionizing radiation could induce foetal malformations in some mouse strains when administered during early pre-implantation stages. Starting in 1989, data obtained in Germany also showed that radiation exposure during that period could lead to a genomic instability in the surviving foetuses. Furthermore, the same group reported that both malformations and genomic instability could be transmitted to the next generation foetuses after exposure of zygotes to relatively high doses of radiation. As such results were of concern for radiation protection, we investigated this in more detail during recent years, using mice with varying genetic backgrounds including mice heterozygous for mutations involved in important cellular processes like DNA repair, cell cycle regulation or apoptosis. The main parameters which were investigated included morphological development, genomic instability and gene expression in the irradiated embryos or their own progeny. The aim of this review is to critically reassess the results obtained in that field in the different laboratories and to try to draw general conclusions on the risks of developmental defects and genomic instability from an exposure of early embryos to moderate doses of ionizing radiation. Altogether and in the range of doses normally used in diagnostic radiology, the risk of induction of embryonic death and of congenital malformation following the irradiation of a newly fertilised egg is certainly very low when compared to the ‘spontaneous’ risks for such effects. Similarly, the risk of radiation induction of a genomic instability under such circumstances seems to be very small. However, this is not a reason to not apply some precaution principles when possible. One way of doing this is to restrict the use of higher dose examinations on all potentially pregnant women to the first ten days of their menstrual cycle when conception is very unlikely to have occurred

Craniofacial and Dental Aspects of Crouzon and Apert Syndrome

OpenAIRE

Reitsma, Jacobus Harmen

2014-01-01

markdownabstract__Abstract__ The cranium of an infant or young child consists of different bony plates intersected by sutures. A calvarial suture is a type of fibrous joint in the cranium. The growth of the cranium is effectuated mainly in the sutures. Two important functions of the calvarial sutures are to secure flexibility of the cranium during passage of a baby through the birth canal, and to facilitate growth and separation of the calvarial bones during intrauterine and perinatal life (P...

Syndromes and Disorders Associated with Omphalocele (III: Single Gene Disorders, Neural Tube Defects, Diaphragmatic Defects and Others

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Chih-Ping Chen

2007-06-01

Full Text Available Omphalocele can be associated with single gene disorders, neural tube defects, diaphragmatic defects, fetal valproate syndrome, and syndromes of unknown etiology. This article provides a comprehensive review of omphalocele-related disorders: otopalatodigital syndrome type II; Melnick–Needles syndrome; Rieger syndrome; neural tube defects; Meckel syndrome; Shprintzen–Goldberg omphalocele syndrome; lethal omphalocele-cleft palate syndrome; cerebro-costo-mandibular syndrome; fetal valproate syndrome; Marshall–Smith syndrome; fibrochondrogenesis; hydrolethalus syndrome; Fryns syndrome; omphalocele, diaphragmatic defects, radial anomalies and various internal malformations; diaphragmatic defects, limb deficiencies and ossification defects of skull; Donnai–Barrow syndrome; CHARGE syndrome; Goltz syndrome; Carpenter syndrome; Toriello–Carey syndrome; familial omphalocele; Cornelia de Lange syndrome; C syndrome; Elejalde syndrome; Malpuech syndrome; cervical ribs, Sprengel anomaly, anal atresia and urethral obstruction; hydrocephalus with associated malformations; Kennerknecht syndrome; lymphedema, atrial septal defect and facial changes; and craniosynostosis- mental retardation syndrome of Lin and Gettig. Perinatal identification of omphalocele should alert one to the possibility of omphalocele-related disorders and familial inheritance and prompt a thorough genetic counseling for these disorders.

Application of elastic net and infrared spectroscopy in the discrimination between defective and non-defective roasted coffees.

Science.gov (United States)

Craig, Ana Paula; Franca, Adriana S; Oliveira, Leandro S; Irudayaraj, Joseph; Ileleji, Klein

2014-10-01

The quality of the coffee beverage is negatively affected by the presence of defective coffee beans and its evaluation still relies on highly subjective sensory panels. To tackle the problem of subjectivity, sophisticated analytical techniques have been developed and have been shown capable of discriminating defective from non-defective coffees after roasting. However, these techniques are not adequate for routine analysis, for they are laborious (sample preparation) and time consuming, and reliable, simpler and faster techniques need to be developed for such purpose. Thus, it was the aim of this study to evaluate the performance of infrared spectroscopic methods, namely FTIR and NIR, for the discrimination of roasted defective and non-defective coffees, employing a novel statistical approach. The classification models based on Elastic Net exhibited high percentage of correct classification, and the discriminant infrared spectra variables extracted provided a good interpretation of the models. The discrimination of defective and non-defective beans was associated with main chemical descriptors of coffee, such as carbohydrates, proteins/amino acids, lipids, caffeine and chlorogenic acids. Copyright © 2014 Elsevier B.V. All rights reserved.

Magnetoencephalography signals are influenced by skull defects.

Science.gov (United States)

Lau, S; Flemming, L; Haueisen, J

2014-08-01

Magnetoencephalography (MEG) signals had previously been hypothesized to have negligible sensitivity to skull defects. The objective is to experimentally investigate the influence of conducting skull defects on MEG and EEG signals. A miniaturized electric dipole was implanted in vivo into rabbit brains. Simultaneous recording using 64-channel EEG and 16-channel MEG was conducted, first above the intact skull and then above a skull defect. Skull defects were filled with agar gels, which had been formulated to have tissue-like homogeneous conductivities. The dipole was moved beneath the skull defects, and measurements were taken at regularly spaced points. The EEG signal amplitude increased 2-10 times, whereas the MEG signal amplitude reduced by as much as 20%. The EEG signal amplitude deviated more when the source was under the edge of the defect, whereas the MEG signal amplitude deviated more when the source was central under the defect. The change in MEG field-map topography (relative difference measure, RDM(∗)=0.15) was geometrically related to the skull defect edge. MEG and EEG signals can be substantially affected by skull defects. MEG source modeling requires realistic volume conductor head models that incorporate skull defects. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Noninvasive, in vivo assessment of mouse retinal structure using optical coherence tomography.

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M Dominik Fischer

Full Text Available BACKGROUND: Optical coherence tomography (OCT is a novel method of retinal in vivo imaging. In this study, we assessed the potential of OCT to yield histology-analogue sections in mouse models of retinal degeneration. METHODOLOGY/PRINCIPAL FINDINGS: We achieved to adapt a commercial 3(rd generation OCT system to obtain and quantify high-resolution morphological sections of the mouse retina which so far required in vitro histology. OCT and histology were compared in models with developmental defects, light damage, and inherited retinal degenerations. In conditional knockout mice deficient in retinal retinoblastoma protein Rb, the gradient of Cre expression from center to periphery, leading to a gradual reduction of retinal thickness, was clearly visible and well topographically quantifiable. In Nrl knockout mice, the layer involvement in the formation of rosette-like structures was similarly clear as in histology. OCT examination of focal light damage, well demarcated by the autofluorescence pattern, revealed a practically complete loss of photoreceptors with preservation of inner retinal layers, but also more subtle changes like edema formation. In Crb1 knockout mice (a model for Leber's congenital amaurosis, retinal vessels slipping through the outer nuclear layer towards the retinal pigment epithelium (RPE due to the lack of adhesion in the subapical region of the photoreceptor inner segments could be well identified. CONCLUSIONS/SIGNIFICANCE: We found that with the OCT we were able to detect and analyze a wide range of mouse retinal pathology, and the results compared well to histological sections. In addition, the technique allows to follow individual animals over time, thereby reducing the numbers of study animals needed, and to assess dynamic processes like edema formation. The results clearly indicate that OCT has the potential to revolutionize the future design of respective short- and long-term studies, as well as the preclinical

A mouse model of prenatal ethanol exposure using a voluntary drinking paradigm.

Science.gov (United States)

Allan, Andrea M; Chynoweth, Julie; Tyler, Lani A; Caldwell, Kevin K

2003-12-01

The incidence of fetal alcohol spectrum disorders is estimated to be as high as 1 in 100 births. Efforts to better understand the basis of prenatal ethanol-induced impairments in brain functioning, and the mechanisms by which ethanol produces these defects, will rely on the use of animal models of fetal alcohol exposure (FAE). Using a saccharin-sweetened alcohol solution, we developed a free-choice, moderate alcohol access model of prenatal alcohol exposure. Stable drinking of a saccharin solution (0.066%) was established in female mice. Ethanol then was added to the saccharin in increasing concentrations (2%, 5%, 10% w/v) every 2 days. Water was always available, and mice consumed standard pellet chow. Control mice drank saccharin solution without ethanol. After a stable baseline of ethanol consumption (14 g/kg/day) was obtained, females were impregnated. Ethanol consumption continued throughout pregnancy and then was decreased to 0% in a step-wise fashion over a period of 6 days after pups were delivered. Characterization of the model included measurements of maternal drinking patterns, blood alcohol levels, food consumption, litter size, pup weight, pup retrieval times for the dams, and effects of FAE on performance in fear-conditioned learning and novelty exploration. Maternal food consumption, maternal care, and litter size and number were all found to be similar for the alcohol-exposed and saccharin control animals. FAE did not alter locomotor activity in an open field but did increase the time spent inspecting a novel object introduced into the open field. FAE mice displayed reduced contextual fear when trained using a delay fear conditioning procedure. The mouse model should be a useful tool in testing hypotheses about the neural mechanisms underlying the learning deficits present in fetal alcohol spectrum disorders. Moreover, a mouse prenatal ethanol model should increase the opportunity to use the power of genetically defined and genetically altered mouse

Electrical fingerprint of pipeline defects

International Nuclear Information System (INIS)

Mica, Isabella; Polignano, Maria Luisa; Marco, Cinzia De

2004-01-01

Pipeline defects are dislocations that connect the source region of the transistor with the drain region. They were widely reported to occur in CMOS, BiCMOS devices and recently in SOI technologies. They can reduce device yield either by affecting the devices functionality or by increasing the current consumption under stand-by conditions. In this work the electrical fingerprint of these dislocations is studied, its purpose is to enable us to identify these defects as the ones responsible for device failure. It is shown that the pipeline defects are responsible for a leakage current from source to drain in the transistors. This leakage has a resistive characteristic and it is lightly modulated by the body bias. It is not sensitive to temperature; vice versa the off-current of a good transistor exhibits the well-known exponential dependence on 1/T. The emission spectrum of these defects was studied and compared with the spectrum of a good transistor. The paper aims to show that the spectrum of a defective transistor is quite peculiar; it shows well defined peaks, whereas the spectrum of a good transistor under saturation conditions is characterized by a broad spectral light emission distribution. Finally the deep-level transient spectroscopy (DLTS) is tried on defective diodes

Purkinje Cell Compartmentation in the Cerebellum of the Lysosomal Acid Phosphatase 2 Mutant Mouse (Nax - Naked-Ataxia Mutant Mouse)

Science.gov (United States)

Bailey, Karen; Rahimi Balaei, Maryam; Mannan, Ashraf; Del Bigio, Marc R.; Marzban, Hassan

2014-01-01

The Acp2 gene encodes the beta subunit of lysosomal acid phosphatase, which is an isoenzyme that hydrolyzes orthophosphoric monoesters. In mice, a spontaneous mutation in Acp2 results in severe cerebellar defects. These include a reduced size, abnormal lobulation, and an apparent anterior cerebellar disorder with an absent or hypoplastic vermis. Based on differential gene expression in the cerebellum, the mouse cerebellar cortex can normally be compartmentalized anteroposteriorly into four transverse zones and mediolaterally into parasagittal stripes. In this study, immunohistochemistry was performed using various Purkinje cell compartmentation markers to examine their expression patterns in the Acp2 mutant. Despite the abnormal lobulation and anterior cerebellar defects, zebrin II and PLCβ4 showed similar expression patterns in the nax mutant and wild type cerebellum. However, fewer stripes were found in the anterior zone of the nax mutant, which could be due to a lack of Purkinje cells or altered expression of the stripe markers. HSP25 expression was uniform in the central zone of the nax mutant cerebellum at around postnatal day (P) 18–19, suggesting that HSP25 immunonegative Purkinje cells are absent or delayed in stripe pattern expression compared to the wild type. HSP25 expression became heterogeneous around P22–23, with twice the number of parasagittal stripes in the nax mutant compared to the wild type. Aside from reduced size and cortical disorganization, both the posterior zone and nodular zone in the nax mutant appeared less abnormal than the rest of the cerebellum. From these results, it is evident that the anterior zone of the nax mutant cerebellum is the most severely affected, and this extends beyond the primary fissure into the rostral central zone/vermis. This suggests that ACP2 has critical roles in the development of the anterior cerebellum and it may regulate anterior and central zone compartmentation. PMID:24722417

Defect spectroscopy of single ZnO microwires

Science.gov (United States)

Villafuerte, M.; Ferreyra, J. M.; Zapata, C.; Barzola-Quiquia, J.; Iikawa, F.; Esquinazi, P.; Heluani, S. P.; de Lima, M. M.; Cantarero, A.

2014-04-01

The point defects of single ZnO microwires grown by carbothermal reduction were studied by microphotoluminescence, photoresistance excitation spectra, and resistance as a function of the temperature. We found the deep level defect density profile along the microwire showing that the concentration of defects decreases from the base to the tip of the microwires and this effect correlates with a band gap narrowing. The results show a characteristic deep defect levels inside the gap at 0.88 eV from the top of the VB. The resistance as a function of the temperature shows defect levels next to the bottom of the CB at 110 meV and a mean defect concentration of 4 × 1018 cm-3. This combination of techniques allows us to study the band gap values and defects states inside the gap in single ZnO microwires and opens the possibility to be used as a defect spectroscopy method.

Impurity Role In Mechanically Induced Defects

International Nuclear Information System (INIS)

Howell, R.H.; Asoka-Kumar, P.; Hartley, J.; Sterne, P.

2000-01-01

An improved understanding of dislocation dynamics and interactions is an outstanding problem in the multi scale modeling of materials properties, and is the current focus of major theoretical efforts world wide. We have developed experimental and theoretical tools that will enable us to measure and calculate quantities defined by the defect structure. Unique to the measurements is a new spectroscopy that determines the detailed elemental composition at the defect site. The measurements are based on positron annihilation spectroscopy performed with a 3 MeV positron beam [1]. Positron annihilation spectroscopy is highly sensitive to dislocations and associated defects and can provide unique elements of the defect size and structure. Performing this spectroscopy with a highly penetrating positron beam enables flexibility in sample handling. Experiments on fatigued and stressed samples have been done and in situ measurement capabilities have been developed. We have recently performed significant upgrades to the accelerator operation and novel new experiments have been performed [2-4] To relate the spectrographic results and the detailed structure of a defect requires detailed calculations. Measurements are coupled with calculated results based on a description of positions of atoms at the defect. This gives an atomistic view of dislocations and associated defects including impurity interactions. Our ability to probe impurity interactions is a unique contribution to defect understanding not easily addressed by other atomistic spectroscopies

Normal social seeking behavior, hypoactivity and reduced exploratory range in a mouse model of Angelman syndrome

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Reiter Lawrence T

2011-01-01

Full Text Available Abstract Background Angelman syndrome (AS is a neurogenetic disorder characterized by severe developmental delay with mental retardation, a generally happy disposition, ataxia and characteristic behaviors such as inappropriate laughter, social-seeking behavior and hyperactivity. The majority of AS cases are due to loss of the maternal copy of the UBE3A gene. Maternal Ube3a deficiency (Ube3am-/p+, as well as complete loss of Ube3a expression (Ube3am-/p-, have been reproduced in the mouse model used here. Results Here we asked if two characteristic AS phenotypes - social-seeking behavior and hyperactivity - are reproduced in the Ube3a deficient mouse model of AS. We quantified social-seeking behavior as time spent in close proximity to a stranger mouse and activity as total time spent moving during exploration, movement speed and total length of the exploratory path. Mice of all three genotypes (Ube3am+/p+, Ube3am-/p+, Ube3am-/p- were tested and found to spend the same amount of time in close proximity to the stranger, indicating that Ube3a deficiency in mice does not result in increased social seeking behavior or social dis-inhibition. Also, Ube3a deficient mice were hypoactive compared to their wild-type littermates as shown by significantly lower levels of activity, slower movement velocities, shorter exploratory paths and a reduced exploratory range. Conclusions Although hyperactivity and social-seeking behavior are characteristic phenotypes of Angelman Syndrome in humans, the Ube3a deficient mouse model does not reproduce these phenotypes in comparison to their wild-type littermates. These phenotypic differences may be explained by differences in the size of the genetic defect as ~70% of AS patients have a deletion that includes several other genes surrounding the UBE3A locus.

Defect properties from X-ray scattering experiments

International Nuclear Information System (INIS)

Peisl, H.

1976-01-01

Lattice distortions due to defects in crystals can be studied most directly by elastic X-ray or neutron scattering experiments. The 'size' of the defects can be determined from the shift of the Bragg reflections. Defect induced diffuse scattering intensity close to and between Bragg reflections gives information on the strength and symmetry of the distortion fields and yields the atomic structure of point defects (interstitials, vacancies, small aggregates). Diffuse scattering is a very sensitive method to decide whether defects are present as isolated point defects or have formed aggregates. X-ray scattering has been used to study defects produced in various ionic crystals by γ- and neutron irradiation. After an introduction to the principles of the method the experimental results will be reviewed and discussed in some detail. (orig.) [de

Modeling of Powder Bed Manufacturing Defects

Science.gov (United States)

Mindt, H.-W.; Desmaison, O.; Megahed, M.; Peralta, A.; Neumann, J.

2018-01-01

Powder bed additive manufacturing offers unmatched capabilities. The deposition resolution achieved is extremely high enabling the production of innovative functional products and materials. Achieving the desired final quality is, however, hampered by many potential defects that have to be managed in due course of the manufacturing process. Defects observed in products manufactured via powder bed fusion have been studied experimentally. In this effort we have relied on experiments reported in the literature and—when experimental data were not sufficient—we have performed additional experiments providing an extended foundation for defect analysis. There is large interest in reducing the effort and cost of additive manufacturing process qualification and certification using integrated computational material engineering. A prerequisite is, however, that numerical methods can indeed capture defects. A multiscale multiphysics platform is developed and applied to predict and explain the origin of several defects that have been observed experimentally during laser-based powder bed fusion processes. The models utilized are briefly introduced. The ability of the models to capture the observed defects is verified. The root cause of the defects is explained by analyzing the numerical results thus confirming the ability of numerical methods to provide a foundation for rapid process qualification.

Determination of defect content and defect profile in semiconductor heterostructures

International Nuclear Information System (INIS)

Zubiaga, A; Garcia, J A; Plazaola, F; Zuniga-Perez, J; Munoz-Sanjose, V

2011-01-01

In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

Determination of defect content and defect profile in semiconductor heterostructures

Energy Technology Data Exchange (ETDEWEB)

Zubiaga, A [Laboratory of Physics, HUT, PO Box 1100, 02015 TKK, Espoo (Finland); Garcia, J A; Plazaola, F [Zientzia eta Teknologia Fakultatea, Euskal Herriko Unbertsitatea, P. K. 644, 48080, Bilbao (Spain); Zuniga-Perez, J; Munoz-Sanjose, V, E-mail: fernando.plazaola@ehu.es [Universitat de Valencia, Departamento de Fisica Aplicada i Electromagnetisme, Dr. Moliner 50, 46100 Burjassot, Valencia (Spain)

2011-01-10

In this article we present an overview of the technique to obtain the defects depth profile and width of a deposited layer and multilayer based on positron annihilation spectroscopy. In particular we apply the method to ZnO and ZnO/ZnCdO layers deposited on sapphire substrates. After introducing some terminology we first calculate the trend that the W/S parameters of the Doppler broadening measurements must follow, both in a qualitative and quantitative way. From this point we extend the results to calculate the width and defect profiles in deposited layer samples.

Congenital heart defects in Williams syndrome.

Science.gov (United States)

Yuan, Shi-Min

2017-01-01

Yuan SM. Congenital heart defects in Williams syndrome. Turk J Pediatr 2017; 59: 225-232. Williams syndrome (WS), also known as Williams-Beuren syndrome, is a rare genetic disorder involving multiple systems including the circulatory system. However, the etiologies of the associated congenital heart defects in WS patients have not been sufficiently elucidated and represent therapeutic challenges. The typical congenital heart defects in WS were supravalvar aortic stenosis, pulmonary stenosis (both valvular and peripheral), aortic coarctation and mitral valvar prolapse. The atypical cardiovascular anomalies include tetralogy of Fallot, atrial septal defects, aortic and mitral valvular insufficiencies, bicuspid aortic valves, ventricular septal defects, total anomalous pulmonary venous return, double chambered right ventricle, Ebstein anomaly and arterial anomalies. Deletion of the elastin gene on chromosome 7q11.23 leads to deficiency or abnormal deposition of elastin during cardiovascular development, thereby leading to widespread cardiovascular abnormalities in WS. In this article, the distribution, treatment and surgical outcomes of typical and atypical cardiac defects in WS are discussed.

Secondary defects in non-metallic solids

International Nuclear Information System (INIS)

Ashbee, K.H.G.; Hobbs, L.W.

1977-01-01

This paper points out features of secondary defect formation which are peculiar to non-metallic solids (excluding elemental semiconductors). Most of the materials of interest are compounds of two or more (usually more or less ionic) atomic species, and immediate consequence of which is a need to maintain both stoichiometry (or accommodate non-stoichiometry) and order. Primary defects in these solids, whether produced thermally, chemically or by irradiation, seldom are present or aggregate in exactly stoichiometric proportions, and the resulting extending defect structures can be quite distinct from those found in metallic solids. Where stoichiometry is maintained, it is often convenient to describe extended defects in terms of alterations in the arrangement of 'molecular' units. The adoption of this procedure enables several novel features of extended defect structures in non-metals to be explained. There are several ways in which a range of non-stoichiometry can be accommodated, which include structural elimination of point defects, nucleation of new coherent phases of altered stoichiometry, and decomposition. (author)

Mitochondrial Protection by Exogenous Otx2 in Mouse Retinal Neurons

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Hyoung-Tai Kim

2015-11-01

Full Text Available OTX2 (orthodenticle homeobox 2 haplodeficiency causes diverse defects in mammalian visual systems ranging from retinal dysfunction to anophthalmia. We find that the retinal dystrophy of Otx2+/GFP heterozygous knockin mice is mainly due to the loss of bipolar cells and consequent deficits in retinal activity. Among bipolar cell types, OFF-cone bipolar subsets, which lack autonomous Otx2 gene expression but receive Otx2 proteins from photoreceptors, degenerate most rapidly in Otx2+/GFP mouse retinas, suggesting a neuroprotective effect of the imported Otx2 protein. In support of this hypothesis, retinal dystrophy in Otx2+/GFP mice is prevented by intraocular injection of Otx2 protein, which localizes to the mitochondria of bipolar cells and facilitates ATP synthesis as a part of mitochondrial ATP synthase complex. Taken together, our findings demonstrate a mitochondrial function for Otx2 and suggest a potential therapeutic application of OTX2 protein delivery in human retinal dystrophy.

Dose-response relationship of cadmium or radiation-induced embryotoxicity in mouse whole embryo culture

International Nuclear Information System (INIS)

Nakashima, Kiyohito; Kawamata, Akitoshi; Matsuoka, Masato; Wakisaka, Takashi; Fujiki, Yoshishige

1988-01-01

Mouse embryos of B6C3F 1 strain were exposed in vitro to 1.2 to 2.2 μM cadmium chloride (Cd) or to 100 to 320 R x-rays, and the effects of the exposure on development were examined after 39 h of culture. Development of embryos was assessed from lethality, formation of the neural tube defect, diameter and protein of yolk sac, crown-rump and head lengths, embryonic protein, and number of somites. Incidence of the neural tube defect increased from 3.4 to 100% by 1.2 to 2.0 μM Cd, while embryo deaths increased from 13.8 to 93.3% by 2.0 to 2.2 μM Cd. Embryonic protein was significantly reduced at the teratogenic range, but the number of somites was only affected by 1.6 to 2.0 μM Cd. X-irradiation at 100 to 320 R induced the neural tube defect in 2.9 to 72.7% of the embryos. An embryolethal effect was observed only at the 320 R dose. Crown-rump and head lengths and embryonic protein were significantly affected at the teratogenic range, but the diameter and protein of yolk sac and number of somites were hardly affected. Cadmium- or radiation-induced response data of both teratogenicity and endpoints indicating inhibition of embryonic development were acceptably fitted to a linear log-probit regression. These regressions suggest that as an estimation of interference in development of embryos, embryonic protein and head length are sensitive endpoints while the number of somites is an insensitive criterion. (author)

Defining defect specifications to optimize photomask production and requalification

Science.gov (United States)

Fiekowsky, Peter

2006-10-01

Reducing defect repairs and accelerating defect analysis is becoming more important as the total cost of defect repairs on advanced masks increases. Photomask defect specs based on printability, as measured on AIMS microscopes has been used for years, but the fundamental defect spec is still the defect size, as measured on the photomask, requiring the repair of many unprintable defects. ADAS, the Automated Defect Analysis System from AVI is now available in most advanced mask shops. It makes the use of pure printability specs, or "Optimal Defect Specs" practical. This software uses advanced algorithms to eliminate false defects caused by approximations in the inspection algorithm, classify each defect, simulate each defect and disposition each defect based on its printability and location. This paper defines "optimal defect specs", explains why they are now practical and economic, gives a method of determining them and provides accuracy data.

Metastable and bistable defects in silicon

International Nuclear Information System (INIS)

Mukashev, Bulat N; Abdullin, Kh A; Gorelkinskii, Yurii V

2000-01-01

Existing data on the properties and structure of metastable and bistable defects in silicon are analyzed. Primary radiation-induced defects (vacancies, self-interstitial atoms, and Frenkel pairs), complexes of oxygen, carbon, hydrogen, and other impurity atoms and defects with negative correlation energy are considered. (reviews of topical problems)

Topological defects in extended inflation

International Nuclear Information System (INIS)

Copeland, E.J.; Kolb, E.W.; Chicago Univ., IL; Liddle, A.R.

1990-04-01

We consider the production of topological defects, especially cosmic strings, in extended inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings. 18 refs

Topological defects in extended inflation

International Nuclear Information System (INIS)

Copeland, E.J.; Kolb, E.W.; Liddle, A.R.

1990-01-01

We consider the production of topological defects, especially cosmic strings, in extended-inflation models. In extended inflation, the Universe passes through a first-order phase transition via bubble percolation, which naturally allows defects to form at the end of inflation. The correlation length, which determines the number density of the defects, is related to the mean size of the bubbles when they collide. This mechanism allows a natural combination of inflation and large-scale structure via cosmic strings

RNase H2 Loss in Murine Astrocytes Results in Cellular Defects Reminiscent of Nucleic Acid-Mediated Autoinflammation

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Kareen Bartsch

2018-03-01

Full Text Available Aicardi–Goutières syndrome (AGS is a rare early onset childhood encephalopathy caused by persistent neuroinflammation of autoimmune origin. AGS is a genetic disorder and >50% of affected individuals bear hypomorphic mutations in ribonuclease H2 (RNase H2. All available RNase H2 mouse models so far fail to mimic the prominent CNS involvement seen in AGS. To establish a mouse model recapitulating the human disease, we deleted RNase H2 specifically in the brain, the most severely affected organ in AGS. Although RNase H2ΔGFAP mice lacked the nuclease in astrocytes and a majority of neurons, no disease signs were apparent in these animals. We additionally confirmed these results in a second, neuron-specific RNase H2 knockout mouse line. However, when astrocytes were isolated from brains of RNase H2ΔGFAP mice and cultured under mitogenic conditions, they showed signs of DNA damage and premature senescence. Enhanced expression of interferon-stimulated genes (ISGs represents the most reliable AGS biomarker. Importantly, primary RNase H2ΔGFAP astrocytes displayed significantly increased ISG transcript levels, which we failed to detect in in vivo in brains of RNase H2ΔGFAP mice. Isolated astrocytes primed by DNA damage, including RNase H2-deficiency, exhibited a heightened innate immune response when exposed to bacterial or viral antigens. Taken together, we established a valid cellular AGS model that utilizes the very cell type responsible for disease pathology, the astrocyte, and phenocopies major molecular defects observed in AGS patient cells.

Defect accumulation under cascade damage conditions

DEFF Research Database (Denmark)

Trinkaus, H.; Singh, B.N.; Woo, C.H.

1994-01-01

in terms of this reaction kinetics taking into account cluster production, dissociation, migration and annihilation at extended sinks. Microstructural features which are characteristic of cascade damage and cannot be explained in terms of the conventional single defect reaction kinetics are emphasized......There is now ample evidence from both experimental and computer simulation studies that in displacement cascades not only intense recombination takes place but also efficient clustering of both self-interstitial atoms (SIAs) and vacancies. The size distributions of the two types of defects produced...... reactions kinetics associated with the specific features of cascade damage is described, with emphasis on asymmetries between SIA and vacancy type defects concerning their production, stability, mobility and interactions with other defects. Defect accumulation under cascade damage conditions is discussed...

Adamts18 deletion results in distinct developmental defects and provides a model for congenital disorders of lens, lung, and female reproductive tract development.

Science.gov (United States)

Ataca, Dalya; Caikovski, Marian; Piersigilli, Alessandra; Moulin, Alexandre; Benarafa, Charaf; Earp, Sarah E; Guri, Yakir; Kostic, Corinne; Arsenijevic, Yvan; Soininen, Raija; Apte, Suneel S; Brisken, Cathrin

2016-11-15

The ADAMTS family comprises 19 secreted metalloproteinases that cleave extracellular matrix components and have diverse functions in numerous disease and physiological contexts. A number of them remain 'orphan' proteases and among them is ADAMTS18, which has been implicated in developmental eye disorders, platelet function and various malignancies. To assess in vivo function of ADAMTS18, we generated a mouse strain with inactivated Adamts18 alleles. In the C57Bl6/Ola background, Adamts18-deficient mice are born in a normal Mendelian ratio, and are viable but show a transient growth delay. Histological examination revealed a 100% penetrant eye defect resulting from leakage of lens material through the lens capsule occurring at embryonic day (E)13.5, when the lens grows rapidly. Adamts18-deficient lungs showed altered bronchiolar branching. Fifty percent of mutant females are infertile because of vaginal obstruction due to either a dorsoventral vaginal septum or imperforate vagina. The incidence of ovarian rete is increased in the mutant mouse strain. Thus, Adamts18 is essential in the development of distinct tissues and the new mouse strain is likely to be useful for investigating ADAMTS18 function in human disease, particularly in the contexts of infertility and carcinogenesis. © 2016. Published by The Company of Biologists Ltd.

Adamts18 deletion results in distinct developmental defects and provides a model for congenital disorders of lens, lung, and female reproductive tract development

Directory of Open Access Journals (Sweden)

Dalya Ataca

2016-11-01

Full Text Available The ADAMTS family comprises 19 secreted metalloproteinases that cleave extracellular matrix components and have diverse functions in numerous disease and physiological contexts. A number of them remain ‘orphan’ proteases and among them is ADAMTS18, which has been implicated in developmental eye disorders, platelet function and various malignancies. To assess in vivo function of ADAMTS18, we generated a mouse strain with inactivated Adamts18 alleles. In the C57Bl6/Ola background, Adamts18-deficient mice are born in a normal Mendelian ratio, and are viable but show a transient growth delay. Histological examination revealed a 100% penetrant eye defect resulting from leakage of lens material through the lens capsule occurring at embryonic day (E13.5, when the lens grows rapidly. Adamts18-deficient lungs showed altered bronchiolar branching. Fifty percent of mutant females are infertile because of vaginal obstruction due to either a dorsoventral vaginal septum or imperforate vagina. The incidence of ovarian rete is increased in the mutant mouse strain. Thus, Adamts18 is essential in the development of distinct tissues and the new mouse strain is likely to be useful for investigating ADAMTS18 function in human disease, particularly in the contexts of infertility and carcinogenesis.

Building defects in Danish construction: project characteristics influencing the occurrence of defects at handover

DEFF Research Database (Denmark)

Schultz, Casper Siebken; Jørgensen, Kirsten; Bonke, Sten

2015-01-01

Defects in construction have gained much attention from both the public and academia. Danish construction is no exception and a number of political initiatives have been established to address the unsatisfying amounts of defects. One of the political initiatives, benchmarking, collects and provides...... those with many and/or serious defects. The article reviews the results from studying two quantitative data sets: (I) benchmarking data from 329 building projects and 621 contracts and (II) questionnaire data from an electronic survey comprising 130 contractors. This study provides in-depth knowledge...

Treatment of Inherited Eye Defects by Systemic Hematopoietic Stem Cell Transplantation.

Science.gov (United States)

Rocca, Celine J; Kreymerman, Alexander; Ur, Sarah N; Frizzi, Katie E; Naphade, Swati; Lau, Athena; Tran, Tammy; Calcutt, Nigel A; Goldberg, Jeffrey L; Cherqui, Stephanie

2015-11-01

Cystinosis is caused by a deficiency in the lysosomal cystine transporter, cystinosin (CTNS gene), resulting in cystine crystal accumulation in tissues. In eyes, crystals accumulate in the cornea causing photophobia and eventually blindness. Hematopoietic stem progenitor cells (HSPCs) rescue the kidney in a mouse model of cystinosis. We investigated the potential for HSPC transplantation to treat corneal defects in cystinosis. We isolated HSPCs from transgenic DsRed mice and systemically transplanted irradiated Ctns-/- mice. A year posttransplantation, we investigated the fate and function of HSPCs by in vivo confocal and fluorescence microscopy (IVCM), quantitative RT-PCR (RT-qPCR), mass spectrometry, histology, and by measuring the IOP. To determine the mechanism by which HSPCs may rescue disease cells, we transplanted Ctns-/- mice with Ctns-/- DsRed HSPCs virally transduced to express functional CTNS-eGFP fusion protein. We found that a single systemic transplantation of wild-type HSPCs prevented ocular pathology in the Ctns-/- mice. Engraftment-derived HSPCs were detected within the cornea, and also in the sclera, ciliary body, retina, choroid, and lens. Transplantation of HSPC led to substantial decreases in corneal cystine crystals, restoration of normal corneal thickness, and lowered IOP in mice with high levels of donor-derived cell engraftment. Finally, we found that HSPC-derived progeny differentiated into macrophages, which displayed tunneling nanotubes capable of transferring cystinosin-bearing lysosomes to diseased cells. To our knowledge, this is the first demonstration that HSPCs can rescue hereditary corneal defects, and supports a new potential therapeutic strategy for treating ocular pathologies.

Quantum computing with defects

Science.gov (United States)

Varley, Joel

2011-03-01

The development of a quantum computer is contingent upon the identification and design of systems for use as qubits, the basic units of quantum information. One of the most promising candidates consists of a defect in diamond known as the nitrogen-vacancy (NV-1) center, since it is an individually-addressable quantum system that can be initialized, manipulated, and measured with high fidelity at room temperature. While the success of the NV-1 stems from its nature as a localized ``deep-center'' point defect, no systematic effort has been made to identify other defects that might behave in a similar way. We provide guidelines for identifying other defect centers with similar properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate systems. To elucidate these points, we compare electronic structure calculations of the NV-1 center in diamond with those of several deep centers in 4H silicon carbide (SiC). Using hybrid functionals, we report formation energies, configuration-coordinate diagrams, and defect-level diagrams to compare and contrast the properties of these defects. We find that the NC VSi - 1 center in SiC, a structural analog of the NV-1 center in diamond, may be a suitable center with very different optical transition energies. We also discuss how the proposed criteria can be translated into guidelines to discover NV analogs in other tetrahedrally coordinated materials. This work was performed in collaboration with J. R. Weber, W. F. Koehl, B. B. Buckley, A. Janotti, C. G. Van de Walle, and D. D. Awschalom. This work was supported by ARO, AFOSR, and NSF.

Disruption of mouse Cenpj, a regulator of centriole biogenesis, phenocopies Seckel syndrome.

Science.gov (United States)

McIntyre, Rebecca E; Lakshminarasimhan Chavali, Pavithra; Ismail, Ozama; Carragher, Damian M; Sanchez-Andrade, Gabriela; Forment, Josep V; Fu, Beiyuan; Del Castillo Velasco-Herrera, Martin; Edwards, Andrew; van der Weyden, Louise; Yang, Fengtang; Ramirez-Solis, Ramiro; Estabel, Jeanne; Gallagher, Ferdia A; Logan, Darren W; Arends, Mark J; Tsang, Stephen H; Mahajan, Vinit B; Scudamore, Cheryl L; White, Jacqueline K; Jackson, Stephen P; Gergely, Fanni; Adams, David J

2012-01-01

Disruption of the centromere protein J gene, CENPJ (CPAP, MCPH6, SCKL4), which is a highly conserved and ubiquitiously expressed centrosomal protein, has been associated with primary microcephaly and the microcephalic primordial dwarfism disorder Seckel syndrome. The mechanism by which disruption of CENPJ causes the proportionate, primordial growth failure that is characteristic of Seckel syndrome is unknown. By generating a hypomorphic allele of Cenpj, we have developed a mouse (Cenpj(tm/tm)) that recapitulates many of the clinical features of Seckel syndrome, including intrauterine dwarfism, microcephaly with memory impairment, ossification defects, and ocular and skeletal abnormalities, thus providing clear confirmation that specific mutations of CENPJ can cause Seckel syndrome. Immunohistochemistry revealed increased levels of DNA damage and apoptosis throughout Cenpj(tm/tm) embryos and adult mice showed an elevated frequency of micronucleus induction, suggesting that Cenpj-deficiency results in genomic instability. Notably, however, genomic instability was not the result of defective ATR-dependent DNA damage signaling, as is the case for the majority of genes associated with Seckel syndrome. Instead, Cenpj(tm/tm) embryonic fibroblasts exhibited irregular centriole and centrosome numbers and mono- and multipolar spindles, and many were near-tetraploid with numerical and structural chromosomal abnormalities when compared to passage-matched wild-type cells. Increased cell death due to mitotic failure during embryonic development is likely to contribute to the proportionate dwarfism that is associated with CENPJ-Seckel syndrome.

Disruption of Mouse Cenpj, a Regulator of Centriole Biogenesis, Phenocopies Seckel Syndrome

Science.gov (United States)

McIntyre, Rebecca E.; Lakshminarasimhan Chavali, Pavithra; Forment, Josep V.; Fu, Beiyuan; Del Castillo Velasco-Herrera, Martin; Edwards, Andrew; van der Weyden, Louise; Yang, Fengtang; Ramirez-Solis, Ramiro; Estabel, Jeanne; Gallagher, Ferdia A.; Logan, Darren W.; Arends, Mark J.; Tsang, Stephen H.; Mahajan, Vinit B.; Scudamore, Cheryl L.; White, Jacqueline K.; Jackson, Stephen P.; Gergely, Fanni; Adams, David J.

2012-01-01

Disruption of the centromere protein J gene, CENPJ (CPAP, MCPH6, SCKL4), which is a highly conserved and ubiquitiously expressed centrosomal protein, has been associated with primary microcephaly and the microcephalic primordial dwarfism disorder Seckel syndrome. The mechanism by which disruption of CENPJ causes the proportionate, primordial growth failure that is characteristic of Seckel syndrome is unknown. By generating a hypomorphic allele of Cenpj, we have developed a mouse (Cenpjtm/tm) that recapitulates many of the clinical features of Seckel syndrome, including intrauterine dwarfism, microcephaly with memory impairment, ossification defects, and ocular and skeletal abnormalities, thus providing clear confirmation that specific mutations of CENPJ can cause Seckel syndrome. Immunohistochemistry revealed increased levels of DNA damage and apoptosis throughout Cenpjtm/tm embryos and adult mice showed an elevated frequency of micronucleus induction, suggesting that Cenpj-deficiency results in genomic instability. Notably, however, genomic instability was not the result of defective ATR-dependent DNA damage signaling, as is the case for the majority of genes associated with Seckel syndrome. Instead, Cenpjtm/tm embryonic fibroblasts exhibited irregular centriole and centrosome numbers and mono- and multipolar spindles, and many were near-tetraploid with numerical and structural chromosomal abnormalities when compared to passage-matched wild-type cells. Increased cell death due to mitotic failure during embryonic development is likely to contribute to the proportionate dwarfism that is associated with CENPJ-Seckel syndrome. PMID:23166506

Hyperelastic "bone": A highly versatile, growth factor-free, osteoregenerative, scalable, and surgically friendly biomaterial.

Science.gov (United States)

Jakus, Adam E; Rutz, Alexandra L; Jordan, Sumanas W; Kannan, Abhishek; Mitchell, Sean M; Yun, Chawon; Koube, Katie D; Yoo, Sung C; Whiteley, Herbert E; Richter, Claus-Peter; Galiano, Robert D; Hsu, Wellington K; Stock, Stuart R; Hsu, Erin L; Shah, Ramille N

2016-09-28

Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic "bone" (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm(3)/hour) from room temperature extruded liquid inks. The resulting 3D-printed HB exhibited elastic mechanical properties (~32 to 67% strain to failure, ~4 to 11 MPa elastic modulus), was highly absorbent (50% material porosity), supported cell viability and proliferation, and induced osteogenic differentiation of bone marrow-derived human mesenchymal stem cells cultured in vitro over 4 weeks without any osteo-inducing factors in the medium. We evaluated HB in vivo in a mouse subcutaneous implant model for material biocompatibility (7 and 35 days), in a rat posterolateral spinal fusion model for new bone formation (8 weeks), and in a large, non-human primate calvarial defect case study (4 weeks). HB did not elicit a negative immune response, became vascularized, quickly integrated with surrounding tissues, and rapidly ossified and supported new bone growth without the need for added biological factors. Copyright © 2016, American Association for the Advancement of Science.

Defect identification using positrons

International Nuclear Information System (INIS)

Beling, C.D.; Fung, S.

2001-01-01

The current use of the lifetime and Doppler broadening techniques in defect identification is demonstrated with two studies, the first being the identification of carbon vacancy in n-6H SiC through lifetime spectroscopy, and the second the production of de-hydrogenated voids in α-Si:H through light soaking. Some less conventional ideas are presented for more specific defect identification, namely (i) the amalgamation of lifetime and Doppler techniques with conventional deep level transient spectroscopy in what may be called ''positron-deep level transient spectroscopy'', and (ii) the extraction of more spatial information on vacancy defects by means of what may be called ''Fourier transform Doppler broadening of annihilation radiation spectroscopy'' (orig.)

Positron lifetime calculation for defects and defect clusters in graphite

International Nuclear Information System (INIS)

Onitsuka, T.; Ohkubo, H.; Takenaka, M.; Tsukuda, N.; Kuramoto, E.

2000-01-01

Calculations of positron lifetime have been made for vacancy type defects in graphite and compared with experimental results. Defect structures were obtained in a model graphite lattice after including relaxation of whole lattice as determined by the molecular dynamics method, where the interatomic potential given by Pablo Andribet, Dominguez-Vazguez, Mari Carmen Perez-Martin, Alonso, Jimenez-Rodriguez [Nucl. Instrum. and Meth. 115 (1996) 501] was used. For the defect structures obtained via lattice relaxation positron lifetime was calculated under the so-called atomic superposition method. Positron lifetimes 204 and 222 ps were obtained for the graphite matrix and a single vacancy, respectively, which can be compared with the experimental results 208 and 233 ps. For planar vacancy clusters, e.g., vacancy loops, lifetime calculation was also made and indicated that lifetime increases with the number of vacancies in a cluster. This is consistent with the experimental result in the region of higher annealing temperature (above 1200 deg. C), where the increase of positron lifetime is seen, probably corresponding to the clustering of mobile vacancies

A Bone-Implant Interaction Mouse Model for Evaluating Molecular Mechanism of Biomaterials/Bone Interaction.

Science.gov (United States)

Liu, Wenlong; Dan, Xiuli; Wang, Ting; Lu, William W; Pan, Haobo

2016-11-01

The development of an optimal animal model that could provide fast assessments of the interaction between bone and orthopedic implants is essential for both preclinical and theoretical researches in the design of novel biomaterials. Compared with other animal models, mice have superiority in accessing the well-developed transgenic modification techniques (e.g., cell tracing, knockoff, knockin, and so on), which serve as powerful tools in studying molecular mechanisms. In this study, we introduced the establishment of a mouse model, which was specifically tailored for the assessment of bone-implant interaction in a load-bearing bone marrow microenvironment and could potentially allow the molecular mechanism study of biomaterials by using transgenic technologies. The detailed microsurgery procedures for developing a bone defect (Φ = 0.8 mm) at the metaphysis region of the mouse femur were recorded. According to our results, the osteoconductive and osseointegrative properties of a well-studied 45S5 bioactive glass were confirmed by utilizing our mouse model, verifying the reliability of this model. The feasibility and reliability of the present model were further checked by using other materials as objects of study. Furthermore, our results indicated that this animal model provided a more homogeneous tissue-implant interacting surface than the rat at the early stage of implantation and this is quite meaningful for conducting quantitative analysis. The availability of transgenic techniques to mechanism study of biomaterials was further testified by establishing our model on Nestin-GFP transgenic mice. Intriguingly, the distribution of Nestin + cells was demonstrated to be recruited to the surface of 45S5 glass as early as 3 days postsurgery, indicating that Nestin + lineage stem cells may participate in the subsequent regeneration process. In summary, the bone-implant interaction mouse model could serve as a potential candidate to evaluate the early stage tissue

Electronic structure of point defects in semiconductors

International Nuclear Information System (INIS)

Bruneval, Fabien

2014-01-01

This 'Habilitation a diriger des Recherches' memoir presents most of my scientific activities during the past 7 years, in the field of electronic structure calculations of defects in solids. Point defects (vacancies, interstitials, impurities) in functional materials are a key parameter to determine if these materials will actually fill the role they have been assigned or not. Indeed, the presence of defects cannot be avoided when the temperature is increased or when the material is subjected to external stresses, such as irradiation in the nuclear reactors and in artificial satellites with solar radiations. However, in many cases, defects are introduced in the materials on purpose to tune the electronic transport, optical or even magnetic properties. This procedure is called the doping of semiconductors, which is the foundation technique for transistors, diodes, or photovoltaic cells. However, doping is not always straightforward and unexpected features may occur, such as doping asymmetry or Fermi level pinning, which can only be explained by complex phenomena involving different types of defects or complexes of defects. In this context, the calculations of electronic structure ab initio is an ideal tool to complement the experimental observations, to gain the understanding of phenomena at the atomic level, and even to predict the properties of defects. The power of the ab initio calculations comes from their ability to describe any system of electrons and nuclei without any specific adjustment. But although there is a strong need for numerical simulations in this field, the ab initio calculations for defects are still under development as of today. The work presented in this memoir summarizes my contributions to methodological developments on this subject. These developments have followed two main tracks. The first topic is the better understanding of the unavoidable finite size effects. Indeed, defects in semiconductors or insulators are generally present in

Point defects and atomic transport in crystals

International Nuclear Information System (INIS)

Lidiard, A.B.

1981-02-01

There are two principle aspects to the theory of atomic transport in crystals as caused by the action of point defects, namely (1) the calculation of relevant properties of the point defects (energies and other thermodynamic characteristics of the different possible defects, activation energies and other mobility parameters) and (2) the statistical mechanics of assemblies of defects, both equilibrium and non-equilibrium assemblies. In the five lectures given here both these aspects are touched on. The first two lectures are concerned with the calculation of relevant point defect properties, particularly in ionic crystals. The first lecture is more general, the second is concerned particularly with some recent calculations of the free volumes of formation of defects in various ionic solids; these solve a rather long-standing problem in this area. The remaining three lectures are concerned with the kinetic theory of defects mainly in relaxation, drift and diffusion situations

Antigravity from a spacetime defect

OpenAIRE

Klinkhamer, F. R.; Queiruga, J. M.

2018-01-01

We argue that there may exist spacetime defects embedded in Minkowski spacetime, which have negative active gravitational mass. One such spacetime defect then repels a test particle, corresponding to what may be called "antigravity."

Sub-surface defect detection using transient thermography

International Nuclear Information System (INIS)

Mohd Zaki Umar; Huda Abdullah; Abdul Razak Hamzah; Wan Saffiey Wan Abdullah; Ibrahim Ahmad; Vavilov, Vladimir

2009-04-01

An experimental research had been carried out to study the potential of transient thermography in detecting sub-surface defect of non-metal material. In this research, eight pieces of bakelite material were used as samples. Each samples had a sub-surface defect in the circular shape with different diameters and depths. Experiment was conducted using one-sided Pulsed Thermal technique. Heating of samples were done using 30 k Watt adjustable quartz lamp while infra red (IR) images of samples were recorded using THV 550 IR camera. These IR images were then analysed with thermo fit TM Pro software to obtain the Maximum Absolute Differential Temperature Signal value, ΔT max and the time of its appearance, τ max (ΔT). Result showed that all defects were able to be detected even for the smallest and deepest defect (diameter = 5 mm and depth = 4 mm). However the highest value of Differential Temperature Signal (ΔT max ), were obtained at defect with the largest diameter, 20 mm and at the shallowest depth, 1 mm. As a conclusion, the sensitivity of the pulsed thermography technique to detect sub-surface defects of bakelite material is proportionately related with the size of defect diameter if the defect area at the same depth. On the contrary, the sensitivity of the pulsed thermography technique inversely related with the depth of defect if the defects have similar diameter size. (author)

Mouse SNP Miner: an annotated database of mouse functional single nucleotide polymorphisms

Directory of Open Access Journals (Sweden)

Ramensky Vasily E

2007-01-01

Full Text Available Abstract Background The mapping of quantitative trait loci in rat and mouse has been extremely successful in identifying chromosomal regions associated with human disease-related phenotypes. However, identifying the specific phenotype-causing DNA sequence variations within a quantitative trait locus has been much more difficult. The recent availability of genomic sequence from several mouse inbred strains (including C57BL/6J, 129X1/SvJ, 129S1/SvImJ, A/J, and DBA/2J has made it possible to catalog DNA sequence differences within a quantitative trait locus derived from crosses between these strains. However, even for well-defined quantitative trait loci ( Description To help identify functional DNA sequence variations within quantitative trait loci we have used the Ensembl annotated genome sequence to compile a database of mouse single nucleotide polymorphisms (SNPs that are predicted to cause missense, nonsense, frameshift, or splice site mutations (available at http://bioinfo.embl.it/SnpApplet/. For missense mutations we have used the PolyPhen and PANTHER algorithms to predict whether amino acid changes are likely to disrupt protein function. Conclusion We have developed a database of mouse SNPs predicted to cause missense, nonsense, frameshift, and splice-site mutations. Our analysis revealed that 20% and 14% of missense SNPs are likely to be deleterious according to PolyPhen and PANTHER, respectively, and 6% are considered deleterious by both algorithms. The database also provides gene expression and functional annotations from the Symatlas, Gene Ontology, and OMIM databases to further assess candidate phenotype-causing mutations. To demonstrate its utility, we show that Mouse SNP Miner successfully finds a previously identified candidate SNP in the taste receptor, Tas1r3, that underlies sucrose preference in the C57BL/6J strain. We also use Mouse SNP Miner to derive a list of candidate phenotype-causing mutations within a previously

Electron irradiation-induced defects in {beta}-SiC

Energy Technology Data Exchange (ETDEWEB)

Oshima, Ryuichiro [Osaka Prefectural Univ., Sakai (Japan). Reseach Inst. for Advanced Science and Technology

1996-04-01

To add information of point defects in cubic crystal SiC, polycrystal {beta}-SiC on the market was used as sample and irradiated by neutron and electron. In situ observation of neutron and electron irradiation-induced defects in {beta}-SiC were carried out by ultra high-voltage electronic microscope (UHVEM) and ordinary electronic microscope. The obtained results show that the electron irradiation-induced secondary defects are micro defects less than 20 nm at about 1273K, the density of defects is from 2x10{sup 17} to 1x10{sup 18}/cc, the secondary defects may be hole type at high temperature and the preexistant defects control nuclear formation of irradiation-induced defects, effective sink. (S.Y.)

Temporalis myo-osseous flap: an experimental study

International Nuclear Information System (INIS)

Antonyshyn, O.; Colcleugh, R.G.; Hurst, L.N.; Anderson, C.

1986-01-01

The present paper investigates the anatomy and vascularization of the temporalis myo-osseous flap. This is a calvarial bone flap that employs temporalis muscle and its distal pericranial extension as a pedicle. In six human cadavers the flap was raised as an island on the anterior deep temporal artery after transecting the zygomatic arch and coronoid process. Maximal mobilization was thus obtained, allowing rotation of the flap into the mouth for intraoral reconstruction. The arc of rotation and potential surgical applications were noted. A comparative study of the temporalis myo-osseous flap and free calvarial bone graft was then conducted in a rabbit model. Vascularization of the calvarial bone flap was confirmed by technetium scintigraphy performed on the first postoperative day. The uptake of fluorochrome labels immediately after transfer verified the adequacy of the periosteal circulation in maintaining viability and new osteoid formation throughout the full thickness of calvarial bone. The transplantation of free calvarial bone grafts was followed by necrosis of most cellular elements. This was demonstrated by an absence of fluorochrome uptake up to 19 days postoperatively and a predominance of empty lacunae and nonviable marrow

Computer programs for eddy-current defect studies

Energy Technology Data Exchange (ETDEWEB)

Pate, J. R.; Dodd, C. V. [Oak Ridge National Lab., TN (USA)

1990-06-01

Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs.

Computer programs for eddy-current defect studies

International Nuclear Information System (INIS)

Pate, J.R.; Dodd, C.V.

1990-06-01

Several computer programs to aid in the design of eddy-current tests and probes have been written. The programs, written in Fortran, deal in various ways with the response to defects exhibited by four types of probes: the pancake probe, the reflection probe, the circumferential boreside probe, and the circumferential encircling probe. Programs are included which calculate the impedance or voltage change in a coil due to a defect, which calculate and plot the defect sensitivity factor of a coil, and which invert calculated or experimental readings to obtain the size of a defect. The theory upon which the programs are based is the Burrows point defect theory, and thus the calculations of the programs will be more accurate for small defects. 6 refs., 21 figs

Region-Specific Defects of Respiratory Capacities in the Ndufs4(KO Mouse Brain.