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Morphological Characterization (morphological + characterization)
Selected AbstractsTwo-Dye Core/Shell Zeolite Nanoparticles: A New Tool for Ratiometric pH MeasurementsADVANCED FUNCTIONAL MATERIALS, Issue 1 2009Tristan Doussineau Abstract The preparation of core/shell nanoparticles that enable ratiometric pH measurement is described. The core of the nanoparticles consists of a zeolite- , matrix that exhibits a 3-hydroxyflavone reference dye within the porous network. Coating an amorphous silica shell containing a fluorosensor around the zeolite through the Stöber process provides pH sensitivity to the nanoparticles. Morphological characterization (dynamic light scattering, transmission electronic microscopy) demonstrates the control of the sensing silica shell around the zeolite cores, leading to highly monodisperse spherical nanoparticles, while structural characterization (wide-angle X-ray diffraction, nitrogen adsorption) shows the amorphous character of the shell. Spectral characterization via UV/Vis absorption and steady-state fluorescence shows good pH sensitivity of the resulting nanosensors with a pKa suitable for bioanalytical applications. [source] Morphological characterization of GFP stably transfected adult mesenchymal bone marrow stem cellsJOURNAL OF ANATOMY, Issue 1 2006Stefania Raimondo Abstract Increasing attention is being given to the use of adult rather than embryonic stem cells, both for research and for the development of transplantation treatments for human disease. In particular, mesenchymal bone marrow stem cells have been studied extensively because of their ability to self-renew and to give rise to various differentiated cell types, and because of the relative ease with which they can be obtained and cultured. In addition, the possibility of labelling stem cells with green fluorescent protein before transplantation has opened new and promising perspectives for their use in basic research. Because no structural or ultrastructural description of adult mesenchymal stem cells is available in the literature, this paper describes their morphology as revealed by light, confocal and electron microscopy, focusing on cells that are particularly suitable for transplantation studies, i.e. those derived from rat bone marrow transfected with green fluorescent protein. The results provide a basis for experimental studies of the differentiation of these cells in normal and pathological tissues. [source] Morphological characterization of the testicular cells and seminiferous epithelium cycle in six species of Neotropical batsJOURNAL OF MORPHOLOGY, Issue 8 2009Mateus R. Beguelini Abstract We know little about the process of spermatogenesis in bats, a great and diverse clade of mammals that presents different reproductive strategies. In the present study, spermatogenesis in six species of Neotropical bats was investigated by light microscopy. On the basis of chromatin condensation, nuclear morphology, relative position to the basal membrane and formation of the flagellum, three types of spermatogonia were recognized: dark type A (Ad), pale type A (Ap), and type B; the development of spermatids was divided into seven steps. With the exception of Myotis nigricans, the seminiferous epithelium cycle of the other five species studied was similar to those of other mammals, showing gradual stages by the tubular morphology method. Asynchrony was observed in the seminiferous epithelium cycle of M. nigricans, shown by overlapping stages and undefined cycles. The frequencies found in the three phases of the cycle were variable with the greatest frequency occurring in the postmeiotic phase (>50%) and the least in the meiotic phase (<10%). The similarities observed in the five species of Phyllostomidae appeared to be related to their phylogenetic relationship and shorter divergence times, whereas the differences in M. nigricans appeared to be related to its greater phylogenetic distance because the Vespertilionidae family diverged earlier. J. Morphol., 2009. © 2009 Wiley-Liss, Inc. [source] Morphological characterization of the interaction between Diplocarpon rosae and various rose speciesPLANT PATHOLOGY, Issue 1 2005O. Blechert Blackspot, caused by Diplocarpon rosae, is the most severe and ubiquitous disease of garden roses, but information is lacking about genotype-specific forms of resistance and susceptibility of the host. Macro- and microscopic analyses of 34 rose genotypes with a defined monoconidial culture black spot inoculum identified susceptible and resistant rose genotypes and further genotype-specific subdivisions, indicating the presence of partial forms of resistance and different resistance mechanisms. In total, eight interaction types were characterized, five representing compatible (types 1,5) and three representing incompatible interactions (types 6,8). The incompatible interactions were characterized by the lack of any visible fungal structures beneath the cuticle (type 8), single-cell necroses (type 7) or necroses of larger cell clusters (type 6), the latter two types with penetration hyphae and haustoria in epidermal cells. [source] Morphological characterization of retinal bipolar cells in the marine teleost Rhinecanthus aculeatusTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 15 2010Vincenzo Pignatelli Abstract The marine teleost Rhinecanthus aculeatus (Balistidae) has recently been shown to posses trichromatic color vision supported by a retinal combination of double and single cones. Double cones are composed of two members with different spectral sensitivity. It is not known whether a correlation exists between the chromatic wiring of double cones to the inner retina and trichromacy, nor how unmixed, chromatic information is extracted from the two members of the couple. In mammalians, bipolar cells determine color segregation by means of the midget system, central to trichromatic color vision; however, midget bipolar cells have never been described in teleosts. On the basis of its likely importance in transferring chromatic photoreceptor signals to the inner retina, we have morphologically characterized the retinal bipolar cell types of R. aculeatus using DiOlistic staining techniques to verify if an anatomical specialization of this group of cells is required to support trichromatic color vision. Thirteen cell types are described: eight putative OFF types and five putative ON types. Of these, four had axonal boutons ramifying in both sublayers (ON and OFF) of the inner plexiform layer, six had terminals restricted to the OFF layer, and three cell types had terminals restricted to the ON layer. Dendritic arbors of bipolar cells had narrower diameters (5,40 ,m) in comparison to bipolar cells of other teleost species; this supports the idea that a low degree of photoreceptor to bipolar convergence is correlated with trichromacy in this retina and possibly with the function of double cones as color receptors. J. Comp. Neurol. 518:3117,3129, 2010. © 2010 Wiley-Liss, Inc. [source] Disseminated tumor cells in bone marrow following definitive radiotherapy for intermediate or high-risk prostate cancer,THE PROSTATE, Issue 15 2008Arne Berg Abstract Background The purpose of this study was to explore the prevalence of disseminated tumor cells (DTCs) in bone marrow (BM) of clinically progression-free prostate cancer (PC) patients at least 2 years after curatively intended radiotherapy (RT) with or without adjuvant hormone treatment. Methods All patients were T1,3N0M0 with intermediate or high risk of progression. Median time from RT to BM sampling was 5 years (2,8). A standardized immunocytochemical method applying the anticytokeratin antibodies AE1/AE3 was used for DTCs detection in 130 patients. Morphological characterization of immunostained cells was performed to exclude false positive cells. The post-treatment BM was explored in relation to pre-treatment risk factors, treatment strategy and serum levels of Testosterone and PSA at the time of BM sampling. Longitudinal changes in BM status were studied in a sub-group of 109 patients who also had donated BM prior to treatment. Results Post-treatment BM-aspirates were positive for DTCs in 17% of cases without correlation to any of the tested variables. Out of 14 patients who had DTCs in BM prior to treatment, all but one had become post-treatment negative. Out of 95 patients with pre-treatment negative BM status, 18 (19%) had become post-treatment positive. Conclusions DTCs in BM were found in 17% of clinically progression-free PC patients following RT. The detection of these cells may provide PSA-independent prognostic information remaining to be explored by prolonged follow-up. Prostate 68: 1607,1614, 2008. © 2008 Wiley-Liss, Inc. [source] Electrophysiological and morphological characterization of dentate astrocytes in the hippocampusDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2005Masako Isokawa Abstract We studied electrophysiological and morphological properties of astrocytes in the dentate gyrus of the rat hippocampus in slices. Intracellular application of Lucifer yellow revealed two types of morphology: one with a long process extruding from the cell body, and the other with numerous short processes surrounding the cell body. Their electrophysiological properties were either passive, that is, no detectable voltage-dependent conductance, or complex, with Na+/K+ currents similar to those reported in the Ammon's horn astrocytes. We did not find any morphological correlate to the types of electrophysiological profile or dye coupling. Chelation of cytoplasmic calcium ([Ca2+]i) by BAPTA increased the incidence of detecting a low Na+ conductance and transient outward K+ currents. However, an inwardly rectifying K+ current (Kir), a hallmark of differentiated CA1/3 astrocytes, was not a representative K+ -current in the complex dentate astrocytes, suggesting that these astrocytes could retain an immature form of K-currents. Dentate astrocytes may possess a distinct current profile that is different from those in CA1/3 Ammon's horn. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005 [source] Molecular and morphological characterization of the association between bacterial endosymbionts and the marine nematode Astomonema sp. from the BahamasENVIRONMENTAL MICROBIOLOGY, Issue 5 2007Niculina Musat Summary Marine nematode worms without a mouth or functional gut are found worldwide in intertidal sandflats, deep-sea muds and methane-rich pock marks, and morphological studies show that they are associated with endosymbiotic bacteria. While it has been hypothesized that the symbionts are chemoautotrophic sulfur oxidizers, to date nothing is known about the phylogeny or function of endosymbionts from marine nematodes. In this study, we characterized the association between bacterial endosymbionts and the marine nematode Astomonema sp. from coral reef sediments in the Bahamas. Phylogenetic analysis of the host based on its 18S rRNA gene showed that Astomonema sp. is most closely related to non-symbiotic nematodes of the families Linhomoeidae and Axonolaimidae and is not closely related to marine stilbonematinid nematodes with ectosymbiotic sulfur-oxidizing bacteria. In contrast, phylogenetic analyses of the symbionts of Astomonema sp. using comparative 16S rRNA gene sequence analysis revealed that these are closely related to the stilbonematinid ectosymbionts (95,96% sequence similarity) as well as to the sulfur-oxidizing endosymbionts from gutless marine oligochaetes. The closest free-living relatives of these gammaproteobacterial symbionts are sulfur-oxidizing bacteria from the family Chromatiaceae. Transmission electron microscopy and fluorescence in situ hybridization showed that the bacterial symbionts completely fill the gut lumen of Astomonema sp., suggesting that these are their main source of nutrition. The close phylogenetic relationship of the Astomonema sp. symbionts to known sulfur-oxidizing bacteria as well as the presence of the aprA gene, typically found in sulfur-oxidizing bacteria, indicates that the Astomonema sp. symbionts use reduced sulfur compounds as an energy source to provide their hosts with nutrition. [source] Syzygium cumini leaf and seed extract mediated biosynthesis of silver nanoparticles and their characterizationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2010Vineet Kumar Abstract BACKGROUND: Plant mediated synthesis of metallic nanoparticles has been studied and reported, however, to date, the biomolecules involved in the synthesis of metallic nanoparticles have not been characterized. This study was therefore undertaken to characterize the biomolecules of Syzygium cumini involved in the synthesis of silver nanoparticles. RESULTS: Synthesis kinetics and morphological characterization of silver nanoparticles (SNP) synthesized using leaf extract (LE) and seed extract (SE) as well as their polar (water) fractions from Syzygium cumini were compared. The polyphenols content and high performance liquid chromatography (HPLC) profile of different fractions revealed good correlation between size and synthesis rate of SNP. SE contains more polyphenols and biochemical constituents than LE and therefore, showed higher synthesis rate and bigger sized SNP. To analyse the nature of biomolecules involved in the synthesis of SNP, LE and SE were fractionated on a polarity basis by solvent,solvent partitioning. Only the water fractions of LE and SE showed potential for SNP synthesis. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis of SNP indicated that all fractions catalyze the synthesis of spherical nanoparticles. The average size of SNP synthesized by LE, leaf water fraction, SE and seed water fraction were 30, 29, 92, and 73 nm respectively. CONCLUSION: Results suggest that only highly polar soluble constituents are responsible for SNP synthesis. The size of SNP was found to be directly correlated with the amount of polyphenols as well as surfactants present in the reaction solution. Thus, the amount of polyphenols could be one of the crucial parameters determining the size and distribution of SNP. Copyright © 2010 Society of Chemical Industry [source] Genetic and morphological characterization of a Lake Ohrid endemic, Salmo (Acantholingua) ohridanus with a comparison to sympatric Salmo truttaJOURNAL OF FISH BIOLOGY, Issue A 2006S. Su Analysis of both uni-(two mtDNA gene sequences) and bi-parentally (seven microsatellite loci) inherited genetic markers, together with analysis of 40 morphological characters, described Salmo ohridanus as a highly divergent member of the genus Salmo. Based on comparative substitution rate differences at the cytochrome b gene, and a rough estimated age of the Salmo trutta complex (i.e. at least 2 million years), the S. ohridanus and Salmo obtusirostris clade probably split from a common ancestor of brown trout Salmo trutta >4 million years ago, overlapping with minimum age estimates of the formation of Europe's oldest freshwater habitat, Lake Ohrid. Comparative analysis with Lake Ohrid brown trout (known regionally as Salmo letnica), supported the notion that these fish have more recently colonized the lake and phylogenetically belong to the Adriatic lineage of brown trout. It is further suggested that species-specific saturation in the mtDNA control region underestimated the divergence between S. ohridanus and S. trutta. Evidence of rare hybridization between S. ohridanus and Lake Ohrid brown trout was seen at both mtDNA and microsatellite markers, but there was no support for extensive introgression. [source] AFLP Analysis of Trichoderma spp. from India Compared with Sequence and Morphological-based DiagnosticsJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2005H. K. Buhariwalla Abstract Trichoderma species offer considerable potential for controlling aflatoxin contamination in groundnut and other crops. Initial classification of 48 Trichoderma isolates, derived from four different groundnut cultivation sites in India was based on alignment of 28S rDNA sequences to GenBank sequences of ex-type strains. This was found to be substantially more reliable than our routine morphological characterization, but did not provide a comprehensive diagnostic solution, as unique single nucleotide polymorphism (SNP) haplotypes could not be identified for all species. However, all the Trichoderma isolates could be readily distinguished by amplified fragment length polymorphism (AFLP) analysis, based on six primer pair combinations, which generated 234 polymorphic bands. In addition, individual AFLP bands were identified which differentiate closely related species. Similarly, AFLP bands were identified that correlated with different types of antagonism to Aspergillus flavus. The implications of these results for the development of simple polymerase chain reaction (PCR)-based diagnostic assays for antagonistic isolates of Trichoderma is discussed. [source] Ultrastructural characterization of the new NG97ht human-derived glioma cell line using two different electron microscopy technical proceduresMICROSCOPY RESEARCH AND TECHNIQUE, Issue 4 2009Camila Maria Longo Machado Abstract On the basis of transmission electron microscopy observations in tumor cell lines, oncologists have made innumerous diagnostic and therapeutical progresses. Following this path, the UNICAMP immunopathologies laboratory established the NG97 cell line derived from a human astrocytoma grade III, which when injected to the athymic nude mouse flank developed a grade IV astrocytoma. In this study, we focused on ultrastructural characterization of the NG97 cells after being recovered from xenotransplant (NG97ht). These cells in culture were assayed by two different electron microscopy procedures to characterize ultrastructures related to grade IV astrocytomas and to observe their structures through cell subcultivation. Additionally, comparative morphological descriptions of different cell passages in these technical procedures could be a useful tool for improving electron microscopy cell lineage protocols. Results from many cell passage observations showed ultrastructural similarities, which suggest malignant and glioblastoma phenotypes. In the first procedure, NG97ht cells were harvested and then incorporated into agarose before subjecting them to electron microscopy protocols, whereas in the second one, monolayer cells grew first on cover slides. Comparison among protocols revealed that organelles, cytoplasmatic extensions, spatial conformation of filopodia, and cell attachment to substrate were more preserved in the second procedure. Furthermore, in this latter procedure, a unique ellipsoidal structure was observed, which was already described when dealing with gliosarcoma cell line elsewhere. Therefore, these analyses demonstrated a morphological characterization of a new NG97ht cell line using electron transmission microscopy. Moreover, it has been shown that the second procedure provides more detailed information compared with the first. Microsc. Res. Tech, 2009. © 2008 Wiley-Liss, Inc. [source] A review of morphological techniques for detection of peroxisomal (and mitochondrial) proteins and their corresponding mRNAs during ontogenesis in mice: Application to the PEX5-knockout mouse with Zellweger syndromeMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2003Eveline Baumgart Abstract In the era of application of molecular biological gene-targeting technology for the generation of knockout mouse models to study human genetic diseases, the availability of highly sensitive and reliable methods for the morphological characterization of the specific phenotypes of these mice is of great importance. In the first part of this report, the role of morphological techniques for studying the biology and pathology of peroxisomes is reviewed, and the techniques established in our laboratories for the localization of peroxisomal proteins and corresponding mRNAs in fetal and newborn mice are presented and discussed in the context of the international literature. In the second part, the literature on the ontogenetic development of the peroxisomal compartment in mice, with special emphasis on liver and intestine is reviewed and compared with our own data reported recently. In addition, some recent data on the pathological alterations in the liver of the PEX5,/, mouse with a peroxisomal biogenesis defect are briefly discussed. Finally, the methods developed during these studies for the localization of mitochondrial proteins (respiratory chain complexes and MnSOD) are presented and their advantages and pitfalls discussed. With the help of these techniques, it is now possible to identify and distinguish unequivocally peroxisomes from mitochondria, two classes of cell organelles giving by light microscopy a punctate staining pattern in microscopical immunohistochemical preparations of paraffin-embedded mouse tissues. Microsc. Res. Tech. 61:121,138, 2003. © 2003 Wiley-Liss, Inc. [source] Thermal and morphological characterization of composites prepared by solution crystallization method of high-density polyethylene on carbon nanotubesPOLYMER COMPOSITES, Issue 5 2010Linghao He The morphology, nucleation, and crystallization of polyethylene/carbon nanotubes composites prepared by solution crystallization method of high density polyethylene on Multiwall Carbon Nanotubes (MWNTs) are studied. Transmission electron microscopy (TEM) results show that the center stems of MWNTs are decorated with lamellar crystals. The nonisothermal crystallization kinetics of pure PE and PE/MWNTs composites are investigated by differential scanning calorimetry at various cooling rates. It is found that the Avrami analysis modified by Jeziorny and Mo can describe the nonisothermal crystallization process of pure PE and PE/MWNTs very well. The difference in the value of exponent between PE and PE/MWNTs suggests that addition of the MWNTs influences the mechanism of nucleation and the growth of PE crystallites. On one hand, the increasing of temperature corresponding to the maximum rate of crystallization and the onset crystallization temperature and the study of the nucleation activity reveal that the inorganic component (MWNTs) can act as the nucleating agent to facilitate the crystallization of PE in the hybrids. On the other hand, the decreasing degree of crystallinity and the increasing of half-crystallization time imply that the MWNTs networks confine the crystallization of PE. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Influence of hemicelluloses on the structure and properties of Lyocell fibersPOLYMER ENGINEERING & SCIENCE, Issue 5 2007Huiru Zhang In the present paper the difference in the structure and properties of Lyocell fibers with different hemicelluloses content was investigated. The supermolecular structure and the morphological characterization were compared. The fibril aggregation size was estimated by the cross-polarization magic-angle spinning carbon-13 nuclear magnetic resonance (CP/MAS13C-NMR) spectroscopy. Meanwhile, the difference in the mechanical, the fibrillation resistance and the dyeing properties of Lyocell fiber with different hemicelluloses content was also analyzed. POLYM. ENG. SCI., 47:702,706, 2007. © 2007 Society of Plastics Engineers. [source] Initial Development of Bovine Placentation (Bos indicus) from the Point of View of the Allantois and AmnionANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2009A. C. Assis Neto Summary The aim of this study was to perform a morphological characterization of the initial bovine placental development, between 20 and 70 days post-insemination (p.i.), with emphasis on the differentiation of the allantois and amnion. After collection, the conceptuses were dissected, macroscopically measured and photographically documented. The extraembryonic membranes were cut into fragments measuring 5 cm2, and then fixed in 4% paraformaldehyde for analysis using light microscopy, and in 2.5% glutaraldehyde for use in scanning and transmission electron microscopy. The extraembryonic and fetal membranes presented variable degrees of development throughout the periods analysed. The macroscopic appearance of vascularization of the allantois, its attempt to merge with the chorium and the effective appearance of the first cotyledons in development were the events observed from 30 to 40 days of pregnancy. The measurements of the amnion increased gradually as gestation developed. The allantoic epithelia presented cellular dimorphism from 20 to 25 days of pregnancy, but was shown to be immature from 60 to 70 days of pregnancy. [source] Synthesis, and structural and morphological characterization of iron oxide,ion-exchange resin and ,cellulose nanocomposites,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2001Lorenza Suber Abstract The synthesis and the comparative structural and morphological study of iron oxide nanoparticles in polystyrene-based ion-exchange resins and cellulosics are reported. The synthesis of magnetite was performed under nitrogen atmosphere by an in situ method in the presence of the matrix itself. Scanning and transmission electron microscopy measurements led to a detailed characterization of matrix morphology and of magnetic particle structure, size and morphology. The results show that the matrix influences the iron oxide particle size; the average size is about 7,nm in the resins and 25,nm in the celluloses. In the resins, particles are present inside the pores and as aggregates on the surface of the resin beads, whereas in the cellulose they are present on the surface and in the swollen network of the microfibers constituting the single fibers. Copyright © 2001 John Wiley & Sons, Ltd. [source] Patterns of cryptic hybridization revealed using an integrative approach: a case study on genets (Carnivora, Viverridae, Genetta spp.) from the southern African subregionBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2005PHILIPPE GAUBERT Recent years have seen the development of molecular-based methodologies to investigate hybridization and its impact on the evolutionary process. However, morphological characterization of hybrid zones has only scantily been considered, especially in zootaxa. Thus, the level of congruence between molecular and morphological characters when attempting to detect hybrids remains a poorly tackled area. The genets (genus Genetta) provide an ideal case study for further investigation of the respective contribution of morphology and DNA in hybrid zone characterization because (1) their morphology has recently been exhaustively explored and (2) the existence of hybrid zones in southern Africa was proposed in the literature. We assessed levels of hybridization among the southern African genets, and questioned the role of ecological factors on the hybridization patterns detected. We used an integrative approach involving nine discrete morphological characters and a diagnostic discriminant function, geometric morphometrics and sequences of cytochrome b including collection specimens. The combination of independent materials allowed us to accurately reassess the level of hybridization in southern African genets, and revealed cryptic, interspecific gene flows. Morphology unambiguously detected a low number of G. maculata × G. tigrina hybrids and rejected the hypothesis of a large intergradation zone in KwaZulu-Natal, thus supporting the species status of the two genets. Cytochrome b analyses revealed: (1) cryptic, massive hybridization between G. tigrina and the sympatric G. felina, and (2) a trace of reticulation (one sequence) between G. tigrina and the allopatric G. genetta. The type specimen of G. mossambica Matschie, 1902 is considered to be a morphological hybrid between G. maculata and G. angolensis. Remarkably, the morphological approaches (discrete characters and morphometrics) proved complementary to conclusions derived from cytochrome b sequences. Whilst morphometrics was generally unable to accurately identify all putative hybrids, this approach revealed diagnostic cranial shape differences between recognized species as well as the cryptic G. ,letabae' (included in the super-species G. maculata). Morphometrics also confirmed the diagnostic value and age dependency of discrete characters. Our integrative approach appeared necessary to the detection of cryptic hybridizations and to the comprehensive characterization of hybrid zones. The recurrent detection of hybrids exhibiting tigrina -like coat patterns may suggest (1) asymmetric hybridization of G. tigrina males to females of other species and (2) positive selection for tigrina -like phenotype in South African habitats, but these hypotheses will have to be further tested using other sources of evidence. Despite the precise mosaic of hybrid zones identified in southern African genets, the environmental factors that shape patterns of distribution of hybrids remain unclear. Nevertheless, in the light of our range reassessment, it appears that seasonality of precipitation and periods of annual frost may play stringent roles in the distribution of genets. The complementarity of our results based on morphology and molecules is regarded as encouraging for the further development of integrative approaches in order to better understand the complex phenomena that underlie hybridization processes. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 86, 11,33. [source] Clinical features and morphological characterization of 10 patients with noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS)CLINICAL ENDOCRINOLOGY, Issue 5 2006Justin G. S. Won Summary Objective, Noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS), characterized by postprandial neuroglycopaenia, negative prolonged fasts and negative perioperative localization studies for insulinoma, but positive selective arterial calcium stimulation tests and nesidioblastosis in the gradient-guided resected pancreas, is a rare hypoglycaemic disorder of undetermined aetiology. We analysed the clinical, morphological and immunohistological features to further clarify the aetiology and pathogenesis of this rare disease. Patients, Ten consecutive patients with NIPHS (nine men and one woman, aged 29,78 years) were included in the study. Six of the 10 received a gradient-guided subtotal (70%) or distal (50%) pancreatectomy. In the remaining four patients, diazoxide treatment was initiated and the precise mechanism of its action was assessed by meal tests. Results, All of the patients showed a combination of postprandial neuroglycopaenia, negative prolonged fasts (except one patient) and negative localization studies for insulinoma, but positive calcium stimulation tests and nesidioblastosis in the gradient-guided resected pancreas. Immunohistological studies of the resected pancreatic tissues revealed neither an increased rate of proliferation of ,-cells nor an abnormal synthesis and/or processing of either proinsulin or amylin. Evidence of overexpression of the two pancreatic differentiation factors, PDX-1 and Nkx-6·1, as well as the calcium sensing receptor (CaSR) was absent. Nevertheless, abnormal expression of islet neogenesis-associated protein (INGAP), a human cytokine expressed only in the presence of islet neogenesis, in ducts and/or islets, was identified in three of the five patients studied. All of the six patients who received a surgical operation were relieved of further neuroglycopaenic attacks, but one patient who received a subtotal pancreatectomy developed diabetes. In the remaining four patients who received diazoxide treatment, hypoglycaemic episodes were satisfactorily controlled with an attenuated response of ,-cell peptides to meal stimulation. Conclusions, Our results strengthen the existence of this unique clinical hypoglycaemic syndrome from ,-cell hyperfunction as well as the value of the selective arterial calcium stimulation test in its correct diagnosis and localization. The mechanisms underlying ,-cell hyperfunction and release of insulin to calcium, however, remain poorly characterized. Nevertheless, in a subset of patients with NIPHS, there exists some, as yet undefined, pancreatic humoral/paracrine factor(s) other than proinsulin, amylin, PDX-1, Nkx-6·1 and possibly glucagon-like peptide-1 (GLP-1) that are capable of inducing the INGAP gene and, if activated, will initiate ductal proliferation and islet neogenesis. As for the treatment, we recommend that diazoxide be tried first in each patient and, should it fail, a gradient-guided subtotal or distal pancreatectomy be attempted. [source] Flow cytometric and morphological characterization of platelet-rich plasma gelCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2006Juan Emilio Fernández-Barbero Abstract Background of problems: Platelet-rich plasma (PRP) gel is derived from an autogenous preparation of concentrated platelets and is widely used in implant dentistry as a vector for cell growth factors. However, limited data are available on its structure and composition. The present study was aimed at providing a flow cytometric and ultrastructural characterization of PRP gel. Materials and methods: Twenty PRP gel samples were obtained from healthy volunteers. These PRP gel specimens were prepared for transmission (TEM) and scanning electron microscopy (SEM) examination of their morphological ultrastructure. Flow cytometry with CD41-PE monoclonal antibody was used to detect platelet cells, as this antibody recognizes human-platelet-specific antigen CD41. Results: Both SEM and TEM showed that PRP gel contains two components: a fibrillar material with striated band similar to fibrin filaments, and a cellular component that contains human platelet cells. Both techniques indicated that no morphological elements were bound between the cellular component and the fibrillar material. The cells were confirmed as platelet cells by flow cytometric study after incubation with specific monoclonal antibody CD41-PE. Conclusion: PRP gel contains a fibrillar and a cellular (largely human platelet cell) component. This unique structure may be capable of acting as a vehicle for carrying of cells that are essential for soft/hard tissue regeneration. [source] Photodegradation of Methanol Under UV,Visible Irradiation by Titania Dispersed on Polyester ClothPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 2 2010Kaustava Bhattacharyya Titania supported on polyester fabric (TiO2,PY) with varying titania loadings (2,7 wt%) were prepared via the dip-coating method at room temperature using an aqueous slurry of anatase titania. Structural and morphological characterizations by X-ray diffraction and scanning electron microscopy revealed that the titanium dioxide crystallites deposited on the surface of the polyester fabric were in the micrometer range while their phase remained to be anatase. Photocatalytic activity of TiO2,PY fabric catalysts was evaluated for vapor-phase oxidation of methanol in air as a test reaction in the presence of UV as well as solar radiation under ambient conditions. These catalysts were found to be quite active in both UV and solar irradiation with activity being higher in the former case. CO2 yield from photo-oxidation of methanol depended on titania content and also on its dispersion over polyester fabric support. [source] | ||||||||||||||||||||||||||||