Broad Defect Research Articles

P53 coordinates cranial neural crest cell growth and epithelial-mesenchymal transition/delamination processes

Neural crest development involves epithelial-mesenchymal transition (EMT), during which epithelial cells are converted into individual migratory cells. Notably, the same signaling pathways regulate EMT function during both development and tumor metastasis. p53 plays multiple roles in the prevention of tumor development; however, its precise roles during embryogenesis are less clear. We have investigated the role of p53 in early cranial neural crest (CNC) development in chick and mouse embryos. In the mouse, p53 knockout embryos displayed broad craniofacial defects in skeletal, neuronal and muscle tissues. In the chick, p53 is expressed in CNC progenitors and its expression decreases with their delamination from the neural tube. Stabilization of p53 protein using a pharmacological inhibitor of its negative regulator, MDM2, resulted in reduced SNAIL2 (SLUG) and ETS1 expression, fewer migrating CNC cells and in craniofacial defects. By contrast, electroporation of a dominant-negative p53 construct increased PAX7(+) SOX9(+) CNC progenitors and EMT/delamination of CNC from the neural tube, although the migration of these cells to the periphery was impaired. Investigating the underlying molecular mechanisms revealed that p53 coordinates CNC cell growth and EMT/delamination processes by affecting cell cycle gene expression and proliferation at discrete developmental stages; disruption of these processes can lead to craniofacial defects.

Influence of annealing on the structural and optical properties of ZnO films grown by MOCVD

The properties of ZnO films grown on Si (1 1 1) substrates by Metal-Organic Chemical Vapor Deposition technique using diethylzinc and H 2O as reactant gases are reported. The primary focus is on understanding the origin of deep-level luminescence. As increasing the annealing temperature, a visible emission is observed both in samples annealing in oxygen atmosphere and nitrogen atmosphere. In addition, this broad defect emission becomes obviously asymmetric when the annealing temperature was increased to 1000 °C in oxygen atmosphere. Theoretical investigations have reported that the formation enthalpy of defects is varied under different conditions. With these results, it is suggested that the visible emission in ZnO films annealed in oxygen atmosphere is related to zinc vacancy and oxygen interstitial defects. While, the green emission in ZnO films which were annealed in nitrogen atmosphere is attributed to oxygen vacancy defects.

Nonlesional atopic dermatitis skin is characterized by broad terminal differentiation defects and variable immune abnormalities

Atopic dermatitis (AD) is a common inflammatory skin disease with a T(H)2 and "T22" immune polarity. Despite recent data showing a genetic predisposition to epidermal barrier defects in some patients, a fundamental debate still exists regarding the role of barrier abnormalities versus immune responses in initiating the disease. An extensive study of nonlesional AD (ANL) skin is necessary to explore whether there is an intrinsic predisposition to barrier abnormalities, background immune activation, or both in patients with AD. We sought to characterize ANL skin by determining whether epidermal differentiation and immune abnormalities that characterize lesional AD (AL) skin are also reflected in ANL skin. We performed genomic and histologic profiling of both ANL and AL skin lesions (n = 12 each) compared with normal human skin (n = 10). We found that ANL skin is clearly distinct from normal skin with respect to terminal differentiation and some immune abnormalities and that it has a cutaneous expansion of T cells. We also showed that ANL skin has a variable immune phenotype, which is largely determined by disease extent and severity. Whereas broad terminal differentiation abnormalities were largely similar between involved and uninvolved AD skin, perhaps accounting for the "background skin phenotype," increased expression of immune-related genes was among the most obvious differences between AL and ANL skin, potentially reflecting the "clinical disease phenotype." Our study implies that systemic immune activation might play a role in alteration of the normal epidermal phenotype, as suggested by the high correlation in expression of immune genes in ANL skin with the disease severity index.

Osteoblast connexin43 modulates skeletal architecture by regulating both arms of bone remodeling

Connexin43 (Cx43) has an important role in skeletal homeostasis, and Cx43 gene (Gja1) mutations have been linked to oculodentodigital dysplasia (ODDD), a human disorder characterized by prominent skeletal abnormalities. To determine the function of Cx43 at early steps of osteogenesis and its role in the ODDD skeletal phenotype, we have used the Dermo1 promoter to drive Gja1 ablation or induce an ODDD mutation in the chondro-osteogenic linage. Both Gja1 null and ODDD mutant mice develop age-related osteopenia, primarily due to a progressive enlargement of the medullary cavity and cortical thinning. This phenotype is the consequence of a high bone turnover state, with increased endocortical osteoclast-mediated bone resorption and increased periosteal bone apposition. Increased bone resorption is a noncell autonomous defect, caused by exuberant stimulation of osteoclastogenesis by Cx43-deficient bone marrow stromal cells, via decreased Opg production. The latter is part of a broad defect in osteoblast differentiation and function, which also results in abnormal structural and material properties of bone leading to decreased resistance to mechanical load. Thus Cx43 in osteogenic cells is a critical regulator of both arms of the bone remodeling cycle, its absence causing structural changes remindful of aged or disused bone.

HIV disease progression correlates with the generation of dysfunctional naive CD8low T cells

AbstractHIV infection can result in depletion of total CD4+ T cells and naive CD8+ T cells, and in the generation of dysfunctional effector CD8+ T cells. In this study, we show that naive CD8+ T cells in subjects with progressive HIV disease express low levels of CD8α and CD8β chains. Such naive CD8low T cells display broad signaling defects across the T-cell receptor complex, and their appearance correlates with generalized up-regulation of major histocompatibility complex class I (MHC-I) antigens on peripheral blood mononuclear cells (PBMCs). To explore a causal link between increased MHC-I up-regulation and the generation of naive CD8low T cells, we used the humanized SCID-hu Thy/Liv mouse model to show that HIV infection of the thymus and interferon α (IFNα) treatment alone result in MHC-I up-regulation and in the generation of dysfunctional CD3highCD8+CD4− single-positive 8 (SP8) thymocytes with low expression of CD8. We suggest that dysfunctional naive CD8low T cells are generated as a result of IFNα-mediated up-regulation of MHC-I on stromal cells in the thymus and antigen-presenting cells in the periphery, and that dysfunction in this naive compartment contributes to the immunodeficiency of HIV disease. This study is registered at www.clinicaltrials.gov as NCT00187512.

Ion-beam-induced damage formation in CdTe at a temperature of 15 K

Damage formation in 〈1 1 1〉-oriented CdTe single crystals irradiated with 270 keV Ar ions at fluences ranging from 1.0 × 10 11 to 6.0 × 10 16 cm −2 was investigated in-situ using Rutherford backscattering spectrometry (RBS) in channeling configuration. Irradiation and subsequent analysis were performed at 15 K without changing the target temperature. CdTe is not rendered amorphous even after irradiation with several 10 16 cm −2. Defect profiles calculated from the RBS channeling spectra using the computer code DICADA show the formation of a broad defect distribution which extends much deeper into the crystal than the projected range of the implanted ions. Energy-dependent RBS channeling analysis was used to identify the defects as predominantly uncorrelated displaced lattice atoms.

Point and extended defects in chemical vapour deposited diamond

Homoepitaxially grown single crystal CVD diamond has a dislocation arrangement not seen in natural IIa diamond. Whereas in the latter, dislocations lie on (111) planes along [11̄0] directions, dislocations in CVD diamond lie nearly along the [001] growth axis and are arranged in bundles with almost four fold rotational symmetry. Their large strain is easily seen in birefringence and we model the arrangements in the bundle to account for the singular behaviour of the birefringence when the polarisers are rotated with respect to the crystal. The optical absorption spectrum of brown CVD diamond displays a continuum similar to that found in brown IIa natural diamonds but in addition broad point defect induced bands. We investigate the suggestion that the 2.38 eV (560 nm) peak is related to VNH. We suggest that the breadth of these bands is related to the large structural change when the defect is excited.

HPRT Deficiency Coordinately Dysregulates Canonical Wnt and Presenilin-1 Signaling: A Neuro-Developmental Regulatory Role for a Housekeeping Gene?

We have used microarray-based methods of global gene expression together with quantitative PCR and Western blot analysis to identify dysregulation of genes and aberrant cellular processes in human fibroblasts and in SH-SY5Y neuroblastoma cells made HPRT-deficient by transduction with a retrovirus stably expressing an shRNA targeted against HPRT. Analysis of the microarray expression data by Gene ontology (GO) and Gene Set Enrichment Analysis (GSEA) as well as significant pathway analysis by GeneSpring GX10 and Panther Classification System reveal that HPRT deficiency is accompanied by aberrations in a variety of pathways known to regulate neurogenesis or to be implicated in neurodegenerative disease, including the canonical Wnt/β-catenin and the Alzheimer's disease/presenilin signaling pathways. Dysregulation of the Wnt/β-catenin pathway is confirmed by Western blot demonstration of cytosolic sequestration of β-catenin during in vitro differentiation of the SH-SY5Y cells toward the neuronal phenotype. We also demonstrate that two key transcription factor genes known to be regulated by Wnt signaling and to be vital for the generation and function of dopaminergic neurons; i.e., Lmx1a and Engrailed 1, are down-regulated in the HPRT knockdown SH-SY5Y cells. In addition to the Wnt signaling aberration, we found that expression of presenilin-1 shows severely aberrant expression in HPRT-deficient SH-SY5Y cells, reflected by marked deficiency of the 23 kDa C-terminal fragment of presenilin-1 in knockdown cells. Western blot analysis of primary fibroblast cultures from two LND patients also shows dysregulated presenilin-1 expression, including aberrant proteolytic processing of presenilin-1. These demonstrations of dysregulated Wnt signaling and presenilin-1 expression together with impaired expression of dopaminergic transcription factors reveal broad pleitropic neuro-regulatory defects played by HPRT expression and suggest new directions for investigating mechanisms of aberrant neurogenesis and neuropathology in LND and potential new targets for restoration of effective signaling in this neuro-developmental defect.

会陰部の膀胱直腸皮膚瘻を腹直筋皮弁で再建したフルニエ壊疽の1例

We encountered a case of Fournier's gangrene complicated with vesicorectocutaneous fistula that was treated with a pedicled rectus abdominis muscle flap (pedicled RA m-c flap). A 75-year-old man was admitted with consciousness disorder and swelling of the scrotum. The patient had noticed swelling of the scrotum 4 days before admission, but he had ignored this condition. The scrotum and the penis appeared necrotic. On the basis of clinical and radiological findings, we diagnosed this condition as Fournier's gangrene. Surgical debridement was performed in conjunction with the use of broad-spectrum antibiotics. After the patient's general condition was improved, the broad defect in the perineal tissue was covered with a pedicled rectus abdominis muscle flap. The flap was successful. In Japan, this is the first case of Fournier's gangrene complicated with vesicorectocutaneous fistula that was treated with a pedicled RA m-c flap. In order to determine whether plastic surgery after debridement shortens the duration of hospitalization, we reviewed the cases of 120 patients with Fournier's gangrene in Japan. We conclude that plastic surgery after debridement does not shorten the duration of hospitalization, however, this procedures is very useful to deep and broad defects by Fournier's gangrene.

Increased Glucocorticoid Receptor Expression and Activity Mediate the LPS Resistance of SPRET/EI Mice

SPRET/Ei mice are extremely resistant to acute LPS-induced lethal inflammation when compared with C57BL/6. We found that in vivo SPRET/Ei mice exhibit strongly reduced expression levels of cytokines and chemokines. To investigate the role of the potent anti-inflammatory glucocorticoid receptor (GR) in the SPRET/Ei phenotype, mice were treated with the GR antagonist RU486 or bilateral adrenalectomy. Under such conditions, both C57BL/6 and SPRET/Ei mice were strongly sensitized to LPS, and the differences in LPS response between SPRET/Ei and C57BL/6 mice were completely gone. These results underscore the central role of GR in the LPS hyporesponsiveness of SPRET/Ei mice. Compared with C57BL/6, SPRET/Ei mice were found to express higher GR levels, which were reflected in increased GR transactivation. Using a backcross mapping strategy, we demonstrate that the high GR transcription levels are linked to the Nr3c1 (GR) locus on chromosome 18 itself. Unexpectedly, SPRET/Ei mice exhibit a basal overactivation of the hypothalamic-pituitary-adrenal axis, namely strongly increased corticosterone levels, ACTH levels, and adrenocortical size. As a consequence of the excess of circulating glucocorticoids (GCs), levels of hepatic gluconeogenic enzymes are increased, and insulin secretion from pancreatic β-cells is impaired, both of which result in hyperglycemia and glucose intolerance in SPRET/Ei mice. We conclude that SPRET/Ei mice are unique as they display an unusual combination of elevated GR expression and increased endogenous GC levels. Hence, these mice provide a new and powerful tool for the study of GR- and GC-mediated mechanisms, including immune repressive functions, neuroendocrine regulation, insulin secretion, and carbohydrate metabolism.

Optical and room temperature sensing properties of highly oxygen deficient flower-like ZnO nanostructures

Oxygen deficient zinc oxide (ZnO) thin films were deposited electrochemically on glass substrates which are pre-sputtered with pure zinc (Zn) metal. Well-arranged flower -like nanostructures are observed from the SEM micrographs. The purity and crystallinity of the deposited films were confirmed from X-ray diffraction studies supported by Raman studies. The broad and intense defect induced green emission confirms the high oxygen deficiency in the nanostructures. The flower-like structures as well as the oxygen defects present in the system are indeed very suitable for gas and chemical sensing applications. These films were used for room temperature sensing of three different chemicals viz. acetone, ethanol and ammonia. The sensor was found to be insensitive to the change in different concentrations of acetone while it was found to be sensitive to different concentrations of ethanol and ammonia. The sensor is most suitable for sensing ammonia at room temperature.

The lipoatrophic caveolin-1 deficient mouse model reveals autophagy in mature adipocytes

Adipose tissue lipoatrophy caused by caveolin gene deletion in mice is not linked to defective adipocyte differentiation. We show that adipose tissue development cannot be rescued by endothelial specific caveolin-1 re-expression, indicating primordial role of caveolin in mature adipocytes. Partial or total caveolin deficiency in adipocytes induced broad protein expression defects, including but not limited to previously described down-regulation of Insulin Receptor. Global alterations in protein turnover, and accelerated degradation of long-lived proteins were found in caveolin-deficient adipocytes. Lipidation of endogenous LC3 autophagy marker and distribution of GFP-LC3 into aggregates demonstrated activated autophagy in the absence of caveolin-1 in adipocytes. Furthermore, electron microscopy revealed autophagic vacuoles in caveolin-1 deficient but not control adipocytes. Surprisingly, significant levels of lipidated LC3-II were found around lipid droplets of normal adipocytes, maintained in nutrient rich conditions or isolated from fed mice, which do not display autophagy. Altogether, these data indicate that caveolin deficiency induce autophagy in adipocytes, a feature that is not a physiological response to fasting in normal fat cells. This likely resulted from defective insulin and lipolytic responses that converge in chronic nutrient shortage in adipocytes lacking caveolin-1. This is the first report of a pathological situation with autophagy as an adaptative response to adipocyte failure.

Enhanced room temperature excitonic luminescence in ZnO/polymethyl methacrylate nanocomposites prepared by bulk polymerization

Homogeneous ZnO/polymethyl methacrylate (PMMA) nanocomposites were prepared by incorporating ZnO nanoparticles synthesized in various diols into a PMMA matrix by the free-radical bulk polymerization. Room temperature photoluminescence spectra of the as-grown and PMMA-embedded ZnO nanoparticles exhibit an excitonic band-gap emission at 3.3 eV, a near band-gap emission at ∼3.1 eV and a broad defect band centered at ∼2.4 eV. Relative intensity of the defect versus band-gap luminescence depends on the parameters of ZnO preparation as well as the average particle size. However, PMMA-embedded particles produce a much stronger excitonic luminescence, whereas the ratio of the 3.1 to 2.4 eV remains approximately constant. There is no indication of random lasing threshold pointing to the ZnO/PMMA interfacial origin of the enhanced band-gap emission.

Unexpected findings at diagnostic laparoscopy: caecal incarceration with concurrent appendicitis in a patient with bilateral broad ligament defects

Internal herniations through broad ligament defects are very rare. We present the first report of the triad of broad ligament defect, internal herniation of the caecum and appendicitis. A 36-year-old woman with phocomelia presented with right iliac fossa pain and vomiting. The patient had no previous history of trauma or surgery. Abdominal ultrasound showed a small amount of free fluid. At laparoscopy, bilateral broad ligament defects were found, with herniation of the caecum and an inflamed appendix through the right-sided defect. A laparoscopic salpingo-oophorectomy was required for reduction of the herniated bowel, and an appendicectomy was performed. Broad ligament defects may be congenital or acquired. In this case, in light of the limb abnormality and absence of previous surgery, a congenital aetiology is more likely. Ultrasound scan is not reliable and, although computed tomography may be of help, a diagnostic laparoscopy is the best investigation.

Cathodoluminescence of wide‐band‐gap II‐VI quaternary alloys

AbstractCathodoluminescence has been applied to study 1‐μm‐thick Zn1‐xMgxSySe1‐y alloys grown by molecular beam epitaxy. The observed cathodoluminescence spectra show the main band transition at 2.9 eV and a broad defect band around 2.2 eV. The analysis of the band intensities at different electron‐beam current densities shows different saturation behaviour of the defect band intensities for the samples. The saturation intensity and the luminescence lifetime correlate with the defect luminescence intensity and concentration. This is the reason of luminescence colour changes in dependence on the electron‐beam current density. These results were applied to comparative evaluation of the luminescent defect density. A respective cathodoluminescence imaging was used for observation of structural defects in the surface plane and at the ZnMgSSe‐layer/GaAs‐buffer interface. It enables an express non‐destructive analysis of defect density in the layers and heterostuctures. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Huntingtin-associated Protein-1 Deficiency in Orexin-producing Neurons Impairs Neuronal Process Extension and Leads to Abnormal Behavior in Mice

Huntingtin-associated protein-1 (Hap1) is a neuronal protein that associates with huntingtin, the Huntington disease protein. Although Hap1 and huntingtin are known to be involved in intracellular trafficking, whether and how the impairment of Hap1-associated trafficking leads to neurological pathology and symptoms remain to be seen. As Hap1 is enriched in neuronal cells in the brain, addressing this issue is important in defining the role of defective intracellular trafficking in the selective neuropathology associated with Hap1 dysfunction. Here, we find that Hap1 is abundantly expressed in orexin (hypocretin)-producing neurons (orexin neurons), which are distinctly distributed in the hypothalamus and play an important role in the regulation of feeding and behavior. We created conditional Hap1 knock-out mice to selectively deplete Hap1 in orexin neurons via the Cre-loxP system. These mice show process fragmentation of orexin neurons and reductions in food intake, body weight, and locomotor activity. Sucrose density gradient fractionation reveals that loss of Hap1 in the mouse brain also reduces the distribution of trafficking protein complexes and cargo proteins in the fractions that are enriched in synaptosomes. These results suggest that Hap1 is critical for the transport of multiple proteins to the nerve terminals to maintain the integrity of neuronal processes and that selective disruption of the processes of orexin neurons can cause abnormal feeding and locomotor activity.

Enhanced photoluminescence emission from two-dimensional silicon photonic crystal nanocavities

We present a temperature-dependent photoluminescence study of silicon optical nanocavities formed by introducing point defects into two-dimensional photonic crystals. In addition to the prominent TO-phonon-assisted transition from crystalline silicon at ∼1.10 eV, we observe a broad defect band luminescence from ∼1.05 to ∼1.09 eV. Spatially resolved spectroscopy demonstrates that this defect band is present only in the region where air holes have been etched during the fabrication process. Detectable emission from the cavity mode persists up to room temperature; in strong contrast, the background emission vanishes for T⩾150 K. An Arrhenius-type analysis of the temperature dependence of the luminescence signal recorded either in resonance with the cavity mode or weakly detuned suggests that the higher temperature stability may arise from an enhanced internal quantum efficiency due to the Purcell effect.

Clinical and genetic characterization of Portuguese patients with pseudohypoparathyroidism type Ib

Patients with pseudohypoparathyroidism type Ib (PHP-Ib) present hypocalcemia and hyperphosphatemia, as a consequence of a resistance to PTH action, through its G-protein-coupled receptor, in the renal tubules. This resistance results from tissue-specific silencing of the G-protein alpha-subunit (G(s)α), due to imprinting disruption of its encoding locus--GNAS. In familial PHP-Ib, maternally inherited deletions at the STX16 gene are associated to a regional GNAS methylation defect. In sporadic PHP-Ib, broad methylation changes at GNAS arise from unknown genetic causes. In this study, we describe the clinical presentation of PHP-Ib in four Portuguese patients (two of whom were siblings), and provide further insight for the management of patients with this disease. The diagnosis of PHP-Ib was made after detection of GNAS imprinting defects in each of the cases. In the siblings, a regional GNAS methylation change resulted from a known 3.0 kb STX16 deletion. In the other two patients, the broad methylation defects at GNAS, which were absent in their relatives, resulted from genetic alterations that remain to be identified. We report the first clinical and genetic study of Portuguese patients with PHP-Ib. The genetic identification of a hereditary form of this rare disease allowed an early diagnosis, and may prevent hypocalcemia-related complications.

Synthesis of Fe3O4/ZnO Core-shell Nanoparticles for Photodynamic Therapy Applications

AbstractThe use of nanoparticles as carriers of photosensitizer (PS) molecules for photodynamic therapy (PDT) has attracted much interest on core-shell nanosize structures. Herein, we used a simple aqueous solution method to synthesize Fe3O4/ZnO core-shell nanoparticles. X-ray diffraction (XRD) analyses showed the presence of well defined peaks corresponding to Fe3O4 and ZnO in as-synthesized nanocrystals. Vibrating sample magnetometer (VSM) measurements showed that these nanoparticles exhibited superparamagnetic behavior of the core with no coercivity nor remanence. X-ray photoelectron spectroscopy (XPS) analyses revealed the presence of Zn1/2 and Zn3/2 species on the surface of nanocrystals. Photoluminescence measurements showed excitonic emission of ZnO co-existing with a weak and broad defect- related green emission at room temperature. The generation of singlet oxygen was monitored via the photooxidation of diphenyl-1,3-isobenzofuran (DPBF) with different light sources, followed by absorption spectroscopy at 409 nm. The capability of synthesized nanoparticles to generate singlet oxygen has also been verified.

Internal Herniation of Adnexa Through a Defect of the Broad Ligament: Case Report and Literature Review

Internal herniation through a defect of the broad ligament occurs rarely. Herniation of the ovary rather than the small intestine or colon is extremely rare. We present only the third known case of herniation of the adnexa into a broad ligament defect. A 42-year-old woman, gravida 3, para 2, aborta 1, had severe continuing right lower quadrant pain that was resistant to medical and surgical treatments. The clinical history was significant for long-standing endometriosis, 2 previous laparoscopic procedures to treat endometriosis, and chronic pelvic pain despite medical and surgical treatments. At the second laparoscopic procedure, pelvic endometriosis was excised, and a large defect of the right broad ligament was noted but not treated. At the third operation, right salpingo-oophorectomy was performed to eliminate the large broad ligament defect and the possibility of internal herniation on the right side as a possible explanation for the patient's chronic right lower quadrant pain. Postoperatively, the pain resolved, and the patient has been pain-free for 9 months. This type of internal herniation should be considered in the differential diagnosis in female patients with pelvic pain.