First Characterization (first + characterization)

Distribution by Scientific Domains

Selected Abstracts

First Characterization of an Extended Ammonium-Ammonia Complex 1, [{NH4(NH3)4}+ (,-NH3)2] in the Crystal Structure of [NH4(NH3)4] [Co(C2B9H11)2] ×2NH3.

CHEMINFORM, Issue 11 2005
Thomas Rossmeier
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Anisotropic Behavior of Radiopaque NiTiPt Hypotube for Biomedical Applications

Zhicheng Lin
This paper presents the first characterization of anisotropic stress,strain behavior in micron-sized specimens cut directly from hypotubes, the starting material for the manufacture of endovascular stents and other biomedical devices, of a new radiopaque alloy NiTiPt. Experimental results show that NiTiPt hypotube has very different anisotropic characteristics when compared to its NiTi counterpart including higher tensile strength and strain, higher stress,strain nonlinearity, smaller hysteresis loop, and sharper tails during loading,unloading. [source]

Localization of the mosaic transmembrane serine protease corin to heart myocytes

FEBS JOURNAL, Issue 23 2000
John D. Hooper
Corin cDNA encodes an unusual mosaic type II transmembrane serine protease, which possesses, in addition to a trypsin-like serine protease domain, two frizzled domains, eight low-density lipoprotein (LDL) receptor domains, a scavenger receptor domain, as well as an intracellular cytoplasmic domain. In in vitro experiments, recombinant human corin has recently been shown to activate pro-atrial natriuretic peptide (ANP), a cardiac hormone essential for the regulation of blood pressure. Here we report the first characterization of corin protein expression in heart tissue. We generated antibodies to two different peptides derived from unique regions of the corin polypeptide, which detected immunoreactive corin protein of approximately 125,135 kDa in lysates from human heart tissues. Immunostaining of sections of human heart showed corin expression was specifically localized to the cross striations of cardiac myocytes, with a pattern of expression consistent with an integral membrane localization. Corin was not detected in sections of skeletal or smooth muscle. Corin has been suggested to be a candidate gene for the rare congenital heart disease, total anomalous pulmonary venous return (TAPVR) as the corin gene colocalizes to the TAPVR locus on human chromosome 4. However examination of corin protein expression in TAPVR heart tissue did not show evidence of abnormal corin expression. The demonstrated corin protein expression by heart myocytes supports its proposed role as the pro-ANP convertase, and thus a potentially critical mediator of major cardiovascular diseases including hypertension and congestive heart failure. [source]

PNL2 melanocytic marker in immunohistochemical evaluation of primary mucosal melanoma of the head and neck

Luc G. Morris MD
Abstract Background Histologic diagnosis of mucosal melanoma of the head and neck is difficult, requiring immunohistochemical stains which are less reliable than in cutaneous lesions. PNL-2 is a novel marker that has not been examined in mucosal melanoma. Methods Nine formalin-fixed tissue sections of mucosal melanoma were stained with PNL-2, human melanoma black (HMB)-45, Melan-A, S-100, and microphthalmia transcription factor (MITF). Results Disease in all 9 patients arose from the sinonasal mucosa. Rates of diffuse positive staining with the 4 stains were PNL-2 (77.8%), HMB-45 (77.8%), Melan-A (50%), S-100 (87.5%), and MITF (40%). In 3 patients, PNL2 staining was superior to Melan-A or MITF. Conclusion We report the first characterization of PNL-2 staining in head and neck mucosal melanoma. PNL-2 demonstrates high sensitivity for mucosal melanoma, likely superior to Melan-A and MITF, and comparable to HMB-45, with specificity superior to S-100. We advocate inclusion of PNL2 as an important adjunctive marker in the evaluation of these lesions. © 2008 Wiley Periodicals, Inc. Head Neck, 2008 [source]

Nuclear mitochondrial-like sequences in ants: evidence from Atta cephalotes (Formicidae: Attini)

J. Martins Jr
Abstract Nuclear mitochondrial-like sequences (numts) are copies of mitochondrial DNA that have migrated to the genomic DNA. We present the first characterization of numts in ants, these numts being homologues to a mitochondrial DNA fragment containing loci the 3, portion of the cytochrome oxidase I gene, an intergenic spacer, the tRNA leucine gene and the 5, portion of the cytochrome oxidase II gene. All 67 specimens of Atta cephalotes (Hymenoptera: Formicidae: Attini) investigated had these homologues, which are within two monophyletic groups that we called numt1 and numt2. Numt1 and numt2 sequences are less variable than mitochondrial sequences and released from the severe purifying selection constraining the evolution of mitochondrial genes. Their formation probably involved bottlenecks related to two distinct transfer events of ancient and fast evolving mitochondrial DNA fragments to comparative slowly evolving nuclear DNA regions. [source]

The evolution of volatile compounds profile of "Toscano" dry-cured ham during ripening as revealed by SPME-GC-MS approach,

C. Pugliese
Abstract The volatile compounds profile is an important feature for the characterization of dry-cured hams. Some minor typical Italian products, such as ,Toscano' ham, have been poorly studied in regards to their composition of volatile compounds. In this article, we studied the evolution of the aromatic profile of ,Toscano' dry-cured ham by solid-phase microextraction-gas chromatographic-mass spectrometry (SPME-GC-MS) with ripening. Ten right thighs were cured according to the ,Toscano' PDO protocol, sampled at 0, 1, 3, 6 and 12 months and submitted to volatile compounds analysis by SPME with a Divinylbenzene (DVB)/Carboxen/Polydimethylsiloxane (PDMS) 75-µ Stable Flex fibre. An Agilent 5975C mass selective detector (MSD) spectrometer with electron ionization (EI) source operating in scan mode within the m/z 29,350 range was used for data collection. Seven internal standards, either deuterium labeled or absent in the specimens and chosen to represent low or high boiling esters, alcohols, acids or phenols, were added to the homogenized samples and used to normalize the SPME fibre response to account for response changes upon wearing. Linear calibrations were obtained in this way for selected representative compounds. Over 60 compounds belonging to esters, aldehydes, organic acids, ketones and alcohols were identified by comparison with spectral libraries and Kovats indices. Aldehydes were the most represented chemical family, followed by organic acids, alcohols, ketones and esters. The aldehydes and ketones increased during the first 3 months, when the larger formation of volatiles occurred. For other families, the evolution over time was less evident. The principal component and discriminant analyses of the aromatic profile were effective in classifying the hams at 0, 6 or 12 months of ripening while for 1 and 3 months' samples a partial overlapping was shown. These results represent the first characterization of ,Toscano' ham and may constitute the basis to identify the best ripening time and define an analytical quality standard for this typical ham. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Ivanka Teneva
The accurate determination of species of Cyanoprokaryota/Cyanophyceae has many important applications. These include the assessment of risk with regard to blooms in water reservoirs as well as the identification of species capable of producing valuable bioactive compounds. Commonly, Cyanoprokaryota are classified based on their morphology. However, morphological criteria are not always reliable because they may change, for example, due to environmental factors. Thus, genetic and molecular analyses are a promising additional approach, but their application has so far been limited to relatively few genera. In light of this, we present here the first characterization of species and strains of the genus Phormidium Kütz. based on the cpcB-IGS-cpcA locus of the phycocyanin operon. In phylogenetic analyses using deduced amino acid sequences of the cpcB-cpcA regions, Phormidium was found to be polyphyletic. This analysis appeared to be dominated by the cpcB region, which is characterized by a relatively high percentage of informative substitutions. The percentage of variable positions within the cpcB-IGS-cpcA locus overall was 16.5%, thereby indicating a level of divergence remarkably higher than that reported for Nodularia and Arthrospira in previous studies relying on cpcB-IGS-cpcA. Further, alignment of informative nucleotide substitutions in the cpcB-IGS-cpcA sequences revealed a mosaic distribution, which may be indicative of genetic recombination events. Finally, the length and sequences of the IGS region alone proved useful as markers to differentiate the cyanobacterial genus Phormidium. However, whether the IGS region per se is sufficiently discriminatory to differentiate between Phormidium species or even strains requires further investigation using newly identified Phormidium sequence data. [source]

Matrix metalloproteinase 11 (MMP-11; stromelysin-3) and synthetic inhibitors

Magdalini Matziari
Abstract Matrix metalloproteinase (MMP)-11, or Stromelysin 3, is a particular member of MMP family, a group of zinc-dependent endopeptidases involved in matrix degradation and tissue remodeling. Despite intense efforts since its first characterization 15 years ago, its role and target substrates in different diseases remain largely unknown. While mice with MMP-11 deficiency display no particular phenotype, analysis of different tumorigenesis models with these mice lead to the conclusion that MMP-11 promotes tumor development. In contrast with other MMPs, MMP-11 is unable to degrade any major extracellular matrix component and unlike most of other MMPs that are secreted as inactive proenzymes and activated extracellularly, MMP-11 is secreted under active form. MMP-11 may thus play a unique role in tissue remodeling processes, including those associated with tumor progression. Although MMP-11 and other MMPs have been considered as promising targets to combat cancer, a first series of clinical trials using broad-spectrum MMP inhibitors have not led to significant therapeutic benefits. These disappointing results highlight the need for better understanding of the exact role played by each MMP during the different stages of tumor progression. Among the different strategies to fill this gap, highly specific MMP inhibitors would be of great value. This review provides an update on the selectivity profile of phosphinic MMP-11 synthetic inhibitors developed and discusses the opportunities and limitations to identify inhibitors able to fully discriminate MMP-11 from the other MMPs. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 4, 528,552, 2007 [source]

Expression pattern of the maternal factor zygote arrest 1 (Zar1) in bovine tissues, oocytes, and embryos

Tiziana A.L. Brevini
Abstract Zygote arrest 1 (Zar1) is an ovary-specific maternal factor that plays an essential role during the oocyte-to-embryo transition in mouse. In this species, Zar1 expression is strictly limited to the oocyte, the zygote and, at a lower level, the 2-cell embryo. Aim of the present study was to analyze the presence and the expression pattern of the Zar1 ortholog in bovine tissues and embryos. Reverse transcription (RT)-polymerase chain reaction (PCR) analysis was performed in a panel of bovine tissues, in oocytes and pre-implantation in vitro produced embryos. The results demonstrated that a Zar1 ortholog is present in cattle. In the adult, the gene is expressed in ovary, testis, muscle, and myocardium. The gene is also expressed in the oocyte, the zygote, and in all the stages of embryonic development until blastocyst formation. A semi-quantitative RT-PCR analysis revealed that Zar1 levels are constant through in vitro development with the exception of the 4-cell stage, when a significant increase is observed. The exposure of fertilized oocytes to the RNA polymerase II inhibitor alpha-amanitin was able to suppress this Zar1 increase indicating that transcription of this gene occurs at the 4-cell stage. Zar1 is conserved in cattle but has an expression pattern different from the mouse. In particular, Zar1 expression in the adult is not limited to the ovary and in the embryo is expressed well beyond the oocyte to embryo transition. Moreover, the identification of Zar1 transcription at the 4-cell stage represents the first characterization of one of the genes expressed in cattle embryos before the major onset of embryonic transcription. Mol. Reprod. Dev. 69: 375,380, 2004. © 2004 Wiley-Liss, Inc. [source]