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Results for “Morphological Characterization”

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PubMed2003

Morphological and phylogenetic characterizations of freshwater Thioploca species from Lake Biwa, Japan, and Lake Constance, Germany.

Filamentous, gliding, sulfide-oxidizing bacteria of the genus Thioploca were found on sediments in profundal areas of Lake Biwa, a Japanese freshwater mesotrophic lake, and were characterized morphologically and phylogenetically. The Lake Biwa Thioploca resembled morphologically Thioploca ingrica, a brackish water species from a Danish fjord. The diameters of individual trichomes were 3 to 5.6 microm; the diameters of complete Thioploca filaments ranged from 18 to 75 micro m. The cell lengths ranged from 1.2 to 3.8 micro m. In transmission electron microscope specimens stained with uranyl acetate, dense intracellular particles were found, which did not show any positive signals for phosphorus and sulfur in an X-ray analysis. The 16S rRNA gene of the Thioploca from Lake Biwa was amplified by using newly designed Thioploca-specific primers (706-Thioploca, Biwa160F, and Biwa829R) in combination with general bacterial primers in order to avoid nonspecific amplification of contaminating bacterial DNA. Denaturing gradient gel electrophoresis (DGGE) analysis of the three overlapping PCR products resulted in single DGGE bands, indicating that a single 16S rRNA gene had been amplified. With the same method, the Thioploca from Lake Constance was examined. The 16S rRNA sequence was verified by performing fluorescence in situ hybridization targeted at specific motifs of the Lake Biwa THIOPLOCA: Positive signals were obtained with the bacterial probe EUB-338, the gamma-proteobacterial probe GAM42a, and probe Biwa829 targeting the Lake Biwa THIOPLOCA: Based on the nearly complete 16S rRNA sequence and on morphological similarities, the Thioploca from Lake Biwa and the Thioploca from Lake Constance are closely related to T. ingrica and to each other.

DNA, Bacterial↗

PubMed1988

A controlled silver impregnation method to characterize cultured cardiomyocytes.

A morphological characterization of cultured cardiomyocytes was attempted using a modification of a silver impregnation technique originally described for connective tissue. Cardiac cells, obtained from newborn rats and grown as dissociated cultures on plastic surfaces, were fixed in methanol plus 5% glacial acetic acid, treated with potassium permanganate, decolorized in oxalic acid, sensitized with potassium bichromate, impregnated with a silver-ammonium complex, reduced in gelatin-formalin preparation, toned with gold chloride and fixed in sodium thiosulfate. The cultured cardiac cells tended to form a monolayer, although many myocytes remained isolated. Spherical nuclei, sharply stained with silver, were centrally located and surrounded by relatively plentiful cytoplasm packed with well delineated myofibrils. Contaminating fibroblasts were readily distinguished by their spindle-shaped nuclei and the presence of overstained collagen fibers, as well as the absence of myofibrils. In the absence of specific antibody for immunocytochemical identification of cardiomyocytes, morphological characterization of cell type and degree of differentiation by the controlled silver impregnation procedure described here provides a viable alternative, both in short- and long-term studies.

Animals↗

PubMed2005

3D morphology of cell cultures: a quantitative approach using micrometer synchrotron light tomography.

Current issues in both tissue engineering and cell biology deal with cell behavior extensively in 3D. Here, we explore synchrotron radiation micro-computed tomography as a tool for morphological characterization of such 3D cellular constructs, providing micrometer resolution in soft and hard tissues. Novel image processing techniques allowed quantification of local and global cell distributions, cell density, adhesive cell culture surface, and scaffold geometry. For proof of concept, we applied this technique to characterize the morphology of two cell cultures of different phenotypes, namely human dermal fibroblasts and mouse calvarial osteoblast-like cells, both seeded on a polymer multifilament yarn. From 3D visualizations in these case studies, we saw that the fibroblasts spanned between the yarn filaments and in this way encapsulated the yarn, whereas the osteoblast-like cells lined the filament surfaces and did not span between them. Differences found in cell distribution as a function of distance to the median yarn axis and the closest filament surface, respectively, quantified these qualitative impressions gained from 3D visualizations. Moreover, the volume-normalized adhesive surface differed by one order of magnitude between the two phenotypes. Our approach allows quantitative correlation of local scaffold geometry and cell morphology. It can be used to investigate the influence of cell phenotype as well as various biochemical agents on tissue engineering constructs and the behavior of cells in culture.

Animals↗

PubMed2002

Clinical carotid atherosclerosis.

Atherogenesis is an inflammatory process that begins in childhood. Early detection of atherosclerosis might allow for selection of subjects at risk for future cerebrovascular events at a time when dietary and lifestyle modification may have its greatest impact, and medical intervention may be useful for those who are refractory to such treatment or who are at greater risk for an event. Early detection relies on a knowledge of the distribution of atheroma formation, which can be predicted by understanding the hemodynamic patterns of blood flow. Early formation is accompanied by a vascular remodeling that normalizes the area of the vessel lumen, making early detection impossible by angiography. Elevated serologic markers of inflammation may be used as evidence of formation of atherosclerosis, but inflammatory markers lack sensitivity and specificity. Preliminary evidence supports the ability of MRI to detect early atheroma formation, possibly even before substantial wall thickening occurs. Once atheroma has formed with measurable stenosis, the goal of imaging studies is to predict stroke risk and determine the need for surgical intervention. Subjects with symptomatic high-grade carotid stenosis have been shown to benefit from surgery with a reduced stroke risk when compared with medical management alone, although controversy exists regarding the management of moderate symptomatic carotid stenosis or asymptomatic carotid disease. In these individuals, understanding atheroma morphology may prove to be of greater utility for assessing stroke risk and determining the appropriate management. Morphologic characterization may also be helpful in monitoring the effect of medical intervention. MRI has proven capable of characterizing the morphologic composition of carotid atheroma, although the clinical implications continue to be investigated.

Arteriosclerosis↗

PubMed1984

Methods in laboratory investigation. Isolation of guinea pig monocytes and Kurloff cells: characterization of monocyte subsets by morphology, cytochemistry, and adherence.

Guinea pig mononuclear cells were separated from peripheral blood using high-density Ficoll-Hypaque, following which the monocytes and Kurloff cells were isolated using counterflow centrifugation elutriation and Percoll gradient centrifugation. Monocytes were obtained in four counterflow centrifugation elutriation fractions. Small monocytes (283 micron3) constituted 33% of all monocytes and were acid phosphatase negative, nonadherent cells with a scant cytoplasm but characteristic reniform nucleus. Although present in low purity after counterflow centrifugation elutriation, they were enriched using Percoll gradients to 35%. Large monocytes (317 micron3) comprised 41% of all monocytes and were obtained in 81% purity by counterflow centrifugation elutriation. They were adherent cells positive for acid phosphatase and nonspecific esterase. Peroxidase-positive cells constituted 41 and 33% of the small and large monocytes, respectively. Intermediate-sized monocytes (300 micron3) comprised a mixture of monocytes with characteristics of both small and large monocytes. Very large monocytes (354 micron3) were peroxidase-negative, strongly adherent cells with a distinctive morphology characterized by a spherical nucleus and highly vacuolated cytoplasm. They comprised 7% of the total monocytes and are a heretofore unrecognized cell type in the circulation. These procedures also isolated Kurloff cells in high purity and yield. Kurloff cells are distinct to the guinea pig and were nonadherent cells that did not stain for acid phosphatase, peroxidase, or nonspecific esterase. This is the first report of the successful isolation of Kurloff cells as well as monocytes other than human into fractions that differ in size and function.

Acid Phosphatase↗

PubMed2004

Use of morphology to characterize and manage common adnexal masses.

The use of grey-scale ultrasound morphology to characterize a pelvic mass may also be called 'pattern recognition'. The grey-scale ultrasound image provides us with the same information as that obtained by the surgeon or pathologist when he or she cuts a surgical specimen to see what it looks like inside. Many pelvic masses have such a typical macroscopic appearance that a fairly confident diagnosis can be made on the basis of their macroscopic appearance alone, i.e. on the basis of their grey-scale ultrasound image. This is true of most dermoid cysts, endometriomas, corpus luteum cysts, hydrosalpinges and peritoneal pseudocysts, and of many paraovarian cysts and benign solid ovarian tumours, for example, fibromas, fibrothecomas, thecofibromas, thecomas and Brenner tumours. A mass with irregularities should always evoke suspicion of malignancy. A mass that is completely smooth is almost certainly benign. Papillary projections--considered a strong sign of malignancy--are more common in borderline tumours than in invasive cancers but may also be seen in benign tumours, for example, in adenofibromas. They explain many false-positive ultrasound diagnoses of malignancy. Pattern recognition is superior to all other ultrasound methods (e.g. simple classification systems, scoring systems, mathematical models for calculating the risk of malignancy) for discrimination between benign and malignant extrauterine pelvic masses. Today's often too liberal use of transvaginal ultrasound gives clinicians problems. Many adnexal masses that probably would have remained undetected before the ultrasound era are now found incidentally at transvaginal ultrasound examination in women without symptoms of an adnexal tumour. The natural history of incidentally detected pelvic masses with benign ultrasound morphology is not known. Therefore, the optimal management of such tumours is also unknown.

Adnexal Diseases↗

PubMed2005

Ternary CdSxSe 1-x deposited on Ag(111) by ECALE: synthesis and characterization.

Morphology and electronic properties of CdS, CdSe, and the ternary compounds of formula CdSxSe(1-x) deposited on Ag(111) by ECALE have been characterized as a function of the composition. The number of the attainable x values is limited by the necessity of using well-defined CdS/CdSe deposition sequences. However, the quantitative analysis carried out by XPS and electrochemical stripping experiments indicates that the ECALE method has a good control on composition. The AFM images together with the electrochemical characterization indicate both two-dimensional and three-dimensional growth contributions. The photospectra recorded at CdS film electrodes in liquid junction with an alkaline (poly)sulfide electrolyte show good efficiency of photoconversion and band gap typical of the single crystal. Lower photoconversion efficiency and the presence of subband gap response are observed for CdSe; a possible reason is some crystalline disorder due to lower control of the layer-by-layer deposition in the case of Se. The dependence of band gap on composition of ternary CdSxSe(1-x) ECALE films is monotonic and in agreement with literature data reported for bulk materials.

Journal Article↗

PubMed2004

Morphological-anatomical characterization and molecular identification of Tomentella stuposa ectomycorrhizae and related anatomotypes.

Species in the genus Tomentella (Thelephoraceae) belong to the most frequent and widespread ectomycorrhizal (EM) fungi found in temperate and boreal forests. Although several unidentified tomentelloid morphotypes have been presented as common members of EM communities in coniferous and broad-leaved forests, few tomentelloid EM have been identified and described in detail. In this study, ten tomentelloid EM isolates collected from Populus alba, Quercus cerris and Picea abies stands in Hungary and Germany are characterized and documented by morphological-anatomical methods using light microscopy. The investigated ectomycorrhizae belong to the same brown-black tomentelloid morphotype but form two different anatomotype groups (At I and At II). Molecular taxonomical identification was accomplished using phylogenetic analysis (neighbor joining method) of 49 Tomentella nrDNA-ITS nucleotide sequences including the 10 new and 39 GenBank sequences. The EM isolates clustered into two adjoining clades identical with the two anatomotypes. At II clustered with Tomentella stuposa while At I could not be identified to species. Based on the morphological similarity and the low genetic difference it must be a closely related taxon. A comparison of the recently known tomentelloid EM to T. stuposa is presented. Ecological questions involving abundance and host relationships are discussed.

Base Sequence↗

PubMed2003

Statistical characterization of morphological features of layer-by-layer polymer films by image analysis.

This article presents an image analysis-based approach to the statistical characterization of morphological features in layer-by-layer (LBL) polymer films, which depend on the experimental conditions of fabrication. The method is based on the recently introduced concept of exact dilations. This concept allows the precise determination of all possible parallel contours around any general object and, as a consequence, the respective fully accurate Voronoi partition defined by the objects. With the use of a fast wavefront propagation scheme, such diagrams can be obtained at high speed. The method has been applied to statistically characterize features such as grain size and distribution on LBL polymer films. To do this, the polymer surface is tracked from its highest z values downward to its bottom, and each new connected component is detected as a Voronoi seed. Through determination of equivalent radii of the Voronoi cells, the probability density function characterizing the distribution of the domain radius can then be obtained.

Image Processing, Computer-Assisted↗

PubMed2005

Venom gland of Pachycondyla striata worker ants (Hymenoptera: Ponerinae). Ultrastructural characterization.

Morphological data concerning the venom gland of worker ants of Pachycondyla striata revealed that this gland consists of three distinct regions: an external secretory portion, composed by a secretory filament that bifurcates in order to give rise to other two filaments; an internal secretory portion, represented by the convoluted gland; and a storage portion, represented by a sac-shaped reservoir. The ultrastructural analysis showed that the reservoir is enveloped by a simple pavementous epithelium, coated internally with a cuticle. The external secretory portion is composed by cells forming a simple cubic epithelium, in which the apical portion presents numerous microvilli while the basal portion of the cells shows infoldings of the plasma membrane containing numerous mitochondria. The convoluted gland possesses cells of irregular morphology with nuclei containing condensed chromatin, suggesting inactivity. However, these cells are in fact undergoing secretory activity, which is probably added to the final secretion produced by the gland. The cytoplasm of these cells contains several elements distributed therein, such as ribosomes and polyribosomes, lipid droplets, and protein inclusions in the form of crystals, thus suggestive of protein storage, which would be used by the insect when metabolically required.

Animals↗

PubMed2006

Characterization and morphology of atherosclerotic plaque of coronary arteries: utility of electron-beam tomography to detect non-calcified plaque: a comparison with conventional coronary angiography and intravascular ultrasound.

BACKGROUND: Electron-beam tomography (EBT) may provide useful information about characterization and morphology of atherosclerotic plaque of coronary arteries. MATERIALS AND METHODS: Twenty-six subjects (20 male, 6 female) with suspected coronary heart disease had two routine (r) and one enhanced (e) EBT scans to detect non-calcified plaque (NCP) in the coronary arterial lumen, and were compared with conventional coronary angiograms (CAG) and intravascular ultrasound (IVUS). RESULTS: Three had the sites, which did not have high CT values suggesting calcification in rEBT, nor which was not enhanced by contrast material in eEBT. One had the site with positive CT values that were supposed to be the proliferation intima or organized thrombus and at the corresponding site mixed plaque was observed in the IVUS image. The other two had the site with negative CT values that were supposed to be fat tissue with significant stenosis in CAG. We also made the cross-sectional images of the vessel and the morphology of the NCP, which projected into the lumen, could be evaluated. CONCLUSIONS: We could detect the NCP, differentiate fat tissue from soft tissue and evaluate the morphology of the plaque in EBT.

Aged↗

PubMed2004

Dynamic scale theory for characterizing surface morphology of layer-by-layer films of poly(o-methoxyaniline).

The dynamic scale theory and fractal concepts are employed in the characterization of surface morphological properties of layer-by-layer (LBL) films from poly(o-methoxyaniline) (POMA) alternated with poly(vinyl sulfonic acid) (PVS). The fractal dimensions are found to depend on the procedures to fabricate the POMA/PVS multilayers, particularly with regard to the drying procedures. LBL films obtained via drying in ambient air show a more homogeneous surface, compared to films dried under vacuum or a flow of nitrogen, due to a uniform rearrangement of polymer molecules during solvent evaporation.

Absorption↗

PubMed1991

Malignant histiocytosis X. A distinct clinicopathologic entity.

Histiocytosis X (HX) is characterized morphologically by a proliferation of Langerhans' cells (LC), and most often has an indolent, chronic course. To determine whether a distinct clinicopathologic entity of malignant histiocytosis X exists, the authors examined tissues from 31 patients with HX and divided them into four categories. Group A (19 patients) was characterized morphologically by benign-appearing LC and had an indolent course. The male:female (M:F) ratio was 10:9, and the mean age was 21 years (range, 2 months to 60 years). The immunophenotype of this group was S-100+, vimentin+, LN-2+, LN-3+, lysozyme-, LCA-, Leu-M1-. Group B (three patients) had benign-appearing LC, yet had an aggressive clinical course. All patients were male, with a mean age of 47 years (range, 3 years to 72 years). Organs involved included the liver, spleen, heart, thymus, lung, kidney, and pancreas. The immunophenotype was the same as for Group A. Group C (two patients) had atypical and malignant appearing LC, yet a relatively benign clinical course. The ages were four and 65 years, with one female and one male patient. In both patients, the cells were S-100+, vimentin+, LN-2+, LN-3+, and LCA-. Group D (seven patients) was characterized by atypical and malignant-appearing LC and an aggressive clinical course. The mean age was 25 years (range, congenital to 54 years) with one female and six male patients. Organs involved were the thymus, lungs, spleen, liver, kidney, brain, heart, pancreas, stomach, and muscle. Birbeck granules were found in two patients, and the one patient on which fresh tissue was available was CD1+. The typical immunophenotype was S-100+, vimentin+, LN-2+, LN-3+, Leu-M1-, lysozyme-. The results of our study indicate that (1) a distinct clinical entity of malignant HX, characterized morphologically by malignant-appearing LC and clinically by male predominance, atypical organ involvement, and an aggressive clinical course, does exist; and (2) the morphologic appearance of the LC is an imperfect predictor of the clinical severity of HX.

Adolescent↗

PubMedDate not supplied

Pheochromocytomas and ganglioneuromas in the aging rats: morphological and immunohistochemical characterization.

We investigated, morphologically and immunohistochemically, 74 medullary adrenal tumors, including 64 pheochromocytomas (14 malignant and 50 benign), 9 ganglioneuromas, and 1 malignant schwannoma. The tumors were detected in 2-year-old Wistar and Sprague-Dawley rats from carcinogenicity studies. Morphologically, benign pheochromocytomas were characterized by monomorphic, small, basophilic cells with almost absence of mitoses. Malignant pheochromocytomas presented a low grade of pleomorphism, higher rate of mitoses, necrosis, infiltrative growth and in 1 case metastases in the lung. Ganglioneuromas were characterized by ganglion and neuron-like cells embedded in an eosinophilic matrix containing neurites, Schwann cells, and scant fibrovascular elements. All pheochromocytomas were strongly immunoreactive for tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholamine synthesis. Subpopulations of chromaffin cells expressed chromogranin A (CGA) positivity. Matrix and Schwann cells were positive for S-100 and for glial fibrillary acidic protein (GFAP). In focal areas of the tumors, ganglion cells and axons were positive for neurofilament proteins (NFP) and synaptophysin. Ganglion cells exhibited peripherin and beta-tubulin. Proliferative activity of the tumors was assessed by immunostaining the endogenous cell proliferation associated-antigen Ki-67 and the proliferating cell nuclear antigen (PCNA). As expected, cell proliferation indices were much higher in malignant pheochromocytomas than in benign, yet ganglioneuromas remained immunonegative. Considering that Ki-67 antigen is more specific for cell proliferation, it should be regarded as marker of choice for supporting the differential diagnosis between benign and malignant pheochromocytomas.

Adrenal Gland Neoplasms↗

PubMed2005

Cdc42-MRCK and Rho-ROCK signalling cooperate in myosin phosphorylation and cell invasion.

Actomyosin contractility is a mechanism by which cells exert locomotory force against their environment. Signalling downstream of the small GTPase Rho increases contractility through Rho-kinase (ROCK)-mediated regulation of myosin-II light chain (MLC2) phosphorylation. Cdc42 signalling has been shown to control cell polarity. Tumour cells can move through a three-dimensional matrix with either a rounded morphology characterized by Rho-ROCK dependence or with an elongated morphology characterized by Rho-ROCK independence. Here we show that contractility necessary for elongated morphology and invasion can be generated by Cdc42-MRCK signalling. MRCK (myotonic dystrophy kinase-related Cdc42-binding kinase) cooperates with ROCK in the maintenance of elongated morphology and invasion and either MRCK or ROCK is sufficient for MLC2 phosphorylation, through the inhibitory phosphorylation of myosin phosphatase. By contrast, in rounded ROCK-dependent movement, where MLC2 phosphorylation is higher, MRCK has a smaller role. Our data show that a Cdc42-MRCK signal mediates myosin-dependent cell motility and highlight convergence between Rho and Cdc42 signalling.

Actomyosin↗

PubMed1989

Interest of simultaneous ultrastructural characterization of morphology, cytochemistry and immune phenotype in a case of putative hybrid acute leukaemia.

A case of acute leukaemia is reported in which blast cells expressed some B-related antigens (namely the CALLA antigen) and no peroxidase activity at the optical level; however, some mature granular cells contained Auer rods. Simultaneous characterization of ultrastructural morphology, cytochemistry and immune phenotype was performed. There was an apparent mutual exclusion in the expression of myeloperoxidase activity and the CALLA antigen, and a heterogeneity in the CALLA expression among the blastic population. These results disagree with the hypothesis of a true biphenotypic leukaemia and demonstrate a complete heterogeneity between the lymphoblastoid cells and the myeloid ones. The interest of such a simple combined method in a case of putative hybrid acute leukaemia is emphasized.

Acute Disease↗

PubMed1996

Isolation and biological characterization of morphological transformation-sensitive Syrian hamster embryo cells.

Investigations were carried out designed to isolate and biologically characterize the subpopulation of cells within the Syrian hamster embryo (SHE) cell population which are sensitive to morphological transformation (MT). Biological cloning of MT-sensitive cells demonstrated that within the complex SHE cell population, MT-sensitive cells comprise approximately 27% of the clonally plateable cellular population. Importantly, MT-sensitive cells display MT rates of approximately 7% following benzo[a]pyrene exposure, a rate which falls to <1% with additional passage of the cells, indicating that the ability to undergo MT is a transient phenomenon. Biological characterization of the clonal MT-sensitive cells indicates that these cells are relatively undifferentiated, since they express both cytokeratins and vimentin and respond to a variety of stem cell growth and differentiation factors, although the majority appear to be committed progenitor cells, since they express either mesenchymal or epithelial cell characteristics. Together these data demonstrate that MT-sensitive cells comprise a subpopulation of the cells within the complex SHE cell population, that the ability to undergo MT is a transient phenomenon and that MT-sensitive cells are relatively undifferentiated committed progenitor stem-like cells, all of which gives rise to the hypothesis that MT is an alteration in the cellular differentiation state.

Animals↗

PubMed1997

Further characterization of morphologically defined typical and atypical CLL: a clinical, immunophenotypic, cytogenetic and prognostic study on 390 cases.

We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low-risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I-II), usually required immediate treatment and their survival was shorter. Moreover, clinical staging was of prognostic significance in typical but not in atypical cases. In typical CLL, del(11q) was the most common chromosomal abnormality (21%) whereas in atypical CLL trisomy 12 was found in about 65% of the cases documented with an abnormal karyotype. Although chromosomal abnormalities were associated with a poor survival in typical CLL, they are of no prognostic significance in atypical CLL. Based on these data, we conclude that subtyping CLL by morphology enables the identification of two groups of cases, each characterized by a specific clinical presentation, different cytogenetic abnormalities and prognostic parameters. We speculate that these two groups may represent two related, but different, diseases with different prognostic parameters and a different survival.

Chromosome Aberrations↗