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Presents information on a study which measured the electrical properties of metal/β-FeSi[sub2]/Si double junctions and the optical properties of β-FeSi[sub2]/Si structures. Preparation of epitaxial iron silicide films; Optical measurements; Capacitance measurements; Observation on the ac equivalent circuit for low frequencies; Use of admittance spectroscopy to characterize heterojunctions and obtain energies of impurity levels or band offsets.

Tumour progression in neuroblastoma (NB) patients correlates with high vascular index. We have previously shown that the ACN NB cell line is tumorigenic and angiogenic in immunodeficient mice, and that interferon-γ (IFN-γ) gene transfer dampens ACN tumorigenicity. As IFN-γ represses lymphocyte-induced tumour angiogenesis in various murine models and inhibits proliferation and migration of human endothelial cells, we have investigated the antiangiogenic activity of tumour-derived IFN-γ and the underlying mechanism(s). In addition, we characterised the tumour vasculature of the ACN xenografts, using the chick embryo chorioallantoic membrane assay. We show that the ACN/IFN-γ xenografts had a lower microvessel density and less in vivo angiogenic potential than the vector-transfected ACN/neo. The vascular channels of both xenografts were formed by a mixed endothelial cell population of murine and human origin, as assessed by the FICTION (fluorescence immunophenotyping and interphase cytogenetics) technique. With respect to ACN/neo, the ACN/IFN-γ xenografts showed more terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling-positive human and murine endothelial cells, suggesting that inhibition of angiogenesis by IFN-γ was dependent on the induction of apoptosis, likely mediated by nitric oxide. Once the dual origin of tumour vasculature is confirmed in NB patients, the xenograft model described here will prove useful in testing the efficacy of different antiangiogenic compounds.British Journal of Cancer (2006) 94, 1845–1852. doi:10.1038/sj.bjc.6603186 www.bjcancer.com Published online 23 May 2006 [ABSTRACT FROM AUTHOR]

Activation of the RET protooncogene through somatic rearrangements represents the most common genetic alteration in papillary thyroid carcinoma (PTC). Three main rearranged forms of RET have been described: RET/PTC1 and RET/PTC3, which arise from a paracentric inversion of the long arm of chromosome 10, and RET/PTC2, which originates from a 10;17 translocation. We have developed a dual-color FISH approach to detect RET/PTC rearrangements in interphase nuclei of thyroid lesions. By using a pool of three cosmids encompassing the RET chromosome region and a chromosome 10 centromeric probe, we could discriminate between the presence of an inversion (RET/PTC1 and RET/PTC3) or a translocation (RET/PTC2). We have investigated a series of thyroid tissue samples from Italian and French patients corresponding to a total of 69 PTCs and 22 benign lesions. Among PTCs, 13 (18.8%) showed a RET rearrangement, and 11 (15.9%) of these carried an inversion (RET/PTC1 or RET/PTC3) in more than 10% of the nuclei examined. Activated forms of RET were also observed in three adenomas. RT-PCR analysis on the same samples confirmed the presence and the type of rearrangement predicted using FISH analysis. An interesting difference in the frequency and type of RET rearrangements was detected between the Italian and the French patients. Furthermore, we identified a putative novel type of rearrangement in at least one PTC sample. Several PTCs carried a significant number of cells characterized by a trisomy or a tetrasomy of chromosome 10. Overall, the FISH approach in interphase nuclei represents a powerful tool for detecting, at the single cell level, RET/PTC rearrangements and other anomalies involving the RET chromosome region. Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The very early stages of Pb deposition on Si(111)-(7×7) surfaces have been investigated in real time by scanning tunneling microscopy. Variable temperature measurements combined with unusually long periods of imaging time have enabled us to observe that single Pb atoms are highly mobile within each half of the 7×7 unit cell. Individual jumps of single atoms between different half-cells have been resolved as well as the formation of atom pairs as a result. An activation energy of 0.64±0.07 eV has been measured for the diffusion of single atoms between different half-cells. Pb atom pairs are also mobile inside half-cells at much slower rates than single atoms. An activation energy of 0.40±0.04 eV has been measured for this process. [ABSTRACT FROM AUTHOR]

HOX11L1 is a homeobox gene involved in peripheral nervous system development as confirmed by knockout mice exhibiting megacolon with enteric ganglia, a phenotype associated in human with Intestinal Neuronal Dysplasia (IND). Using FISH and radiation hybrids we have localized HOX11L1 to human chromosome 2p13.1→p12, in a 14-cR interval between WI-5987 (D2S2088) and GCT1B4 (D2S2497), and confirmed the synteny between mouse 6C3–D1 and human 2p13.1→p12 chromosomes by mapping an EST cDNA clone corresponding to mouse HOX11L1 (Tlx2 ). [ABSTRACT FROM AUTHOR]

Semiconducting βFeSi2 has been successfully grown on a Si (111) substrate. It has been proven that under ultrahigh vacuum conditions, the solid phase epitaxy temperature can be lowered to ∼800 K, where only the βFeSi2 phase is stabilized. The disilicide formation was monitored in situ by various surface-sensitive techniques such as low-energy electron diffraction, Auger electron spectroscopy, and ultraviolet photoelectron spectroscopy. The epitaxial relationships were ascertained by transmission electron diffraction and microscopy including high-resolution cross-sectional image. The results show the epitaxy of βFeSi2 (110) and (101) planes parallel to the Si (111) plane. The disilicide-silicon heterojunction displays an atomically abrupt interface. [ABSTRACT FROM AUTHOR]

We report a female patient with a 46,XX,der(8)t(1;8)(q42.1;p23.3) karyotype who had a mild phenotype characterised by a few subtle dysmorphic features and mild developmental retardation, probably resulting from trisomy 1q42-->qter. The deletion on the short arm of the chromosome 8 appeared to be confined to the distal chromosomal segment. [ABSTRACT FROM PUBLISHER]

This article reveals the information about mapping of HOX11L2 gene to human chromosome band 5q35.1 and of its murine homolog to mouse chromosome bands 11A4-A5 by in situ hybridization. Primers designed on the basis of the human HOX11L2 gene sequence were used to screen the CEPH human Mega-YAC library by DNA amplification at the annealing temperature of 62 degree celsius. Results indicate that two overlapping human YAC clones were identified. Fluorescence in situ hybridization experiments localized the two YAC clones on chromosome 5q35.1. Results of radiation hybrid panel are also discussed herein.

Purpose: Malignant cells are genetically unstable and prone to develop chemotherapy resistance, whereas tumor vasculature is usually of host origin and genetically stable. Tumor endothelial microvessels attract interest as therapeutic targets, but their genetic instability would curtail such approach. Here, we have investigated the tumor origin of endothelial microvessels in human neuroblastoma (NB)., Materials and Methods: Paraffin-embedded tissue sections from 10 MYCN-amplified tumors (six stage 4, three stage 3, and one stage 1) were studied. Endothelial cells (ECs) were detected by immunofluorescent staining for CD31 or CD105, and MYCN amplification was detected using fluorescence in situ hybridization (FISH). In xenografts of the HTLA-230 human NB cell line, human ECs were detected by CD31 staining, mouse ECs were detected by CD34 staining, and MYCN amplification and murine DNA were detected using FISH., Results: MYCN-amplified ECs formed approximately 70% of tumor endothelial microvessels in two stage 4 tumors and 20% in one stage 3 tumor. Similar results were obtained after EC labeling with CD31 or CD105. Staining for alpha-smooth muscle actin in combination with MYCN FISH demonstrated that tumor-derived ECs were coated with pericytes. These vessels were functional because they contained RBCs. Approximately 70% of endothelial vessels from HTLA-230 xenografts stained for human CD31, but not murine CD34, and displayed MYCN amplification, thus proving their tumor origin., Conclusion: NB-associated endothelial microvessels can originate from tumor cells, and this finding challenges the tenet that tumor vasculature is genetically stable. The possibility that NB-derived ECs are chemotherapy resistant warrants further investigation.

This study reports on the cytogenetic features of a novel case of pediatric Burkitt-like lymphoma (BLL), that adds to the three published. Four groups of cytogenetic abnormalities were detected in the present case: (1) imbalances shared by most germinal center (GC) derived B-cell tumors including BLL (+1q, -6q, -8p, +8q24 and +11); (2) imbalances already reported in adult but not in pediatric BLL cases and shared with most GC B-cell tumors (+7, -9p, -9q, +12q, -13q, +17, +19, -3 and -4); (3) imbalances already reported in pediatric but not in adult BLL cases and shared with some GC B-cell tumors (-2q); and (4) imbalances never described before in pediatric or adult BLL, but present in different GC B-cell tumors (-6p, -1p and -18q). In view of the paucity of pediatric BLL cases published, this report adds novel, relevant information on the molecular cytogenetic features of this rare tumor.

Congenital central hypoventilation syndrome (CCHS) is a rare syndrome characterized by failure of autonomic respiratory control, often presenting with other dysfunctions of the autonomic nervous system. Segregation analysis suggested a complex model of inheritance with a major locus involved. Disruption of the Rnx gene, a member of the Hox11 family of homeobox genes, in embryonic stem cells produced mice showing a phenotype similar to CCHS. Based on this observation, we have carried out mutation screening of the RNX gene in a set of 13 patients affected with CCHS, 2 of whom showing association with Hirschsprung disease. Single-strand conformational polymorphism analysis and direct sequencing of the whole coding portion of the RNX gene and of 1,311 bp of 5' flanking region were performed. No sequence variant was identified, with the exception of a private nucleotide change at position -874 bp from the ATG codon in two siblings affected with isolated CCHS. A functional test, performed by using the luciferase gene reporter system, has not shown any significant difference in the activity of the promoter region carrying this latter nucleotide change with respect to the wild-type allele. We conclude that RNX, and presumably its expression, are not altered in our index cases of CCHS., (Copyright 2002 Wiley-Liss, Inc.)

Intestinal Neuronal Dysplasia (IND) is a congenital disorder characterized by intestinal motility defects associated with hyperplasia of enteric ganglia. A phenotype resembling human IND has been observed in mice knocked-out for a member of the Hox11 homeobox gene family, Hox11l1, suggesting that the human homologue of this gene could be responsible for congenital disorders of intestinal innervation. However, previous mutation analysis of the coding sequence of the HOX11L1 gene in patients affected with IND detected neither mutations nor other nucleotide variants. In the present work, a detailed study of the non coding promoter region of this gene was undertaken in patients affected with IND, with Hirschsprung associated IND and with neurogenic chronic intestinal pseudo-obstruction. No alterations potentially impairing expression of HOX11L1, such as nucleotide variants, small deletions or cytogenetic alterations, could be identified thus further excluding the direct involvement of this gene in the pathogenesis of human intestinal motility disorders.

Charcot-Marie-Tooth type 4B (CMT4B) is caused by mutations in the myotubularin-related 2 gene, MTMR2, on chromosome 11q22. To date, six loss of function mutations and one missense mutation have been demonstrated in CMT4B patients. It remains to be determined how dysfunction of a ubiquitously expressed phosphatase causes a demyelinating neuropathy. An animal model for CMT4B would provide insights into the pathogenesis of this disorder. We have therefore characterized the mouse homologue of MTMR2 by reconstructing the full-length Mtmr2 cDNA as well as the genomic structure. The 1932 nucleotide open reading frame corresponds to 15 coding exons, spanning a genomic region of approximately 55 kilobases, on mouse chromosome 9 as demonstrated by fluorescence in situ hybridization analysis. A comparison between the mouse and human genes revealed a similar genomic structure, except for the number of alternatively spliced exons in the 5'-untranslated region, two in mouse and three in man. In situ hybridization analysis of mouse embryos showed that Mtmr2 was ubiquitously expressed during organogenesis at E9.5, with some areas of enriched expression. At E14.5, Mtmr2 mRNA was more abundant in the peripheral nervous system, including in dorsal root ganglia and spinal roots.

Glutaredoxins (GRXs) are ubiquitous GSH-dependent oxidoreductases, which catalyze the reduction of protein-glutathionyl-mixed disulfides and are considered to play an important role in the enzymatic regulation of redox-sensitive proteins. In this paper, we describe the identification and characterization of a new human homologue of the SH3BGR gene, named SH3BGRL3 (SH3 domain binding glutamic acid-rich protein like 3). SH3BGRL3 is widely expressed and codes for a highly conserved small protein, which shows a significant similarity to Glutaredoxin 1 (GRX1) of Escherichia coli and is predicted to belong to the Thioredoxin Superfamily. However, the SH3BGRL3 protein lacks both the conserved cysteine residues, which characterize the enzymatic active site of GRX. This structural feature raises the possibility that SH3BGRL3 could function as an endogenous modulator of GRX biological activity. EGFP-SH3BGRL3 fusion protein expressed in COS-7 cells localizes both to the nucleus and to the cytoplasm. The SH3BGRL3 gene was mapped to chromosome 1p34.3-35., (Copyright 2001 Academic Press.)

Hereditary spastic paraplegia (HSP) is a genetically heterogeneous disorder characterised by progressive spasticity of the lower limbs. Beside 'pure' forms of HSP, 'complicated' forms are reported, where spasticity occurs associated with additional symptoms. We recently described an Italian family with a complicated dominant form of HSP (SPG9) and we mapped the gene responsible to 10q23.3-q24.2, in a 12cM interval between markers D10S564 and D10S603. The phenotypic manifestations in our family are reminiscent of those already described in a smaller British pedigree. We typed individuals from this British family using markers located in the SPG9 critical interval and haplotype reconstruction showed the disorder co-segregating with SPG9. To characterise the SPG9 region better, we constructed a contig of 22 YACs, assigned it to 18 polymorphic markers and positioned 54 ESTs. Furthermore, we searched for ESTs containing a trinucleotide repeat sequence, since anticipation of symptoms was reported in both families. Finally, analysis of a muscle biopsy specimen from one patient was normal, suggesting that, contrary to SPG7, mitochondrial disturbance could not be a primary feature of SPG9.