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Results for “Morphological Characterization”

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PubMed1975

Further Chemical and Morphological Characterization of Chloroplast Membranes from a Chlorophyll b-less Mutant of Hordeum vulgare.

A comparative study of peptide composition and freeze-fracture morphology of chloroplast membranes from a chlorophyll b-less mutant and a normal barley plant (Hordeum vulgare L.) is reported in this work. Using a high resolution, discontinuous sodium dodecyl sulfate-acrylamide gel electrophoretic system, we show that the mutant chloroplast membranes not only completely lack the 25-kilodalton peak, which accounts for about 18% of the chloroplast membrane protein in the normal plant, but also exhibit gross reduction in other components at 27.5- and 20-kilodalton regions. Despite such extensive deletions in the peptide composition of the mutant chloroplast lamellae, no alteration could be detected in either density or size of the intramembranous particles, visualized by freeze-fracturing.

Journal Article↗

PubMed2005

Morphology characterization of layer-by-layer films from PAH/MA-co-DR13: the role of film thickness.

We report on the use of dynamic scale theory and fractal analyses in the study of distinct growth stages of layer-by-layer (LBL) films of poly(allylamine hydrochloride) (PAH) and a side-chain-substituted azobenzene copolymer (Ma-co-DR13). The LBL films were adsorbed on glass substrates and characterized with atomic force microscopy with the Ma-co-DR13 at the top layer. The granular morphology exhibited by the films allowed the observation of the growth process inside and outside the grains. The growth outside the grains was found to follow the Kardar-Parisi-Zhang model, with fractal dimensions of ca. 2.6. One could expect that inside the grains the morphology would be close to a Euclidian surface with fractal dimension of ca. 2 for any growth stage. The latter, however, was observed only for thicker films containing more than 10 bilayers. For thinner films the morphology was well described by a self-affine fractal. Such dependence of the growth behavior with the film thickness is associated with a more complete coverage of adsorption sites in thicker films due to diffusion of polymer molecules.

Azo Compounds↗

PubMed1989

Morphological characterization of substance P-like immunoreactive amacrine cells in the anuran retina.

Using substance P immunohistochemistry it was possible to demonstrate a class of morphologically homogeneous group of neurons in the inner nuclear layer (INL) of the retina of two anuran species: Xenopus laevis and Bufo marinus. The number of cells with substance P-like immunoreactivity (SP-LI) was about 250 and 800 in juvenile and 600 and 2500 in adult Xenopus and Bufo, respectively, SP-LI cells had a small soma with one primary dendrite having up to four slender branches, located in the vitreal sublamina of the inner plexiform layer (IPL). Mean dendritic field sizes were 0.12 and 0.30 mm2 in juvenile and 0.29 and 0.65 mm2 in adult Xenopus and Bufo, respectively. The density of SP-LI cells was 40/mm2 in juvenile and 24/mm2 in adult Xenopus compared with 20/mm2 in juvenile and 13/mm2 in adult Bufo. Nearest neighbour distance measurements indicated that SP-LI cells were randomly distributed across the entire retina in both species. The location and the morphology of SP-LI cells indicated that they correspond to a subclass of wide-field amacrine cells, similar to types 20 and 21 described by Golgi techniques in the cat.

Animals↗

PubMed2004

Localization of calcium-binding proteins in physiologically and morphologically characterized interneurons of monkey dorsolateral prefrontal cortex.

In the primate neocortex, little is known about the possible associations between functional subclasses of GABA neurons, their morphological properties and calcium-binding protein (CaBP) content. We used whole-cell current clamp recordings, combined with intracellular labeling and fluorescence immunohistochemistry, to determine these relationships for interneurons in layers 2-3 of monkey prefrontal cortex (PFC). Eighty-one interneurons were included in the analysis. Thirty-eight of these cells showed immunoreactivity for one of the three CaBPs tested. Co-localization of more than one CaBP was not observed in any of the interneurons examined. Interneurons with different CaBPs formed distinct populations with specific physiological membrane properties and morphological features. Parvalbumin (PV)-positive cells had the physiological properties characteristic of fast-spiking interneurons (FS) and the morphology of basket or chandelier neurons. Most calretinin (CR)-containing cells had the physiological properties ascribed to non-fast-spiking cells (non-FS) and a vertically oriented axonal morphology, similar to that of double bouquet cells. Calbindin (CB)-positive interneurons also had non-FS properties and included cells with double bouquet morphology or with a characteristic dense web of axonal collaterals in layer 1. Classification of the interneurons based on cluster analysis of multiple electrophysiological properties suggested the existence of at least two distinct groups of interneurons. The first group contained mainly PV-positive FS cells and the second group consisted predominantly of CR- and CB-positive non-FS interneurons. These findings may help to illuminate the functional roles of different groups of interneurons in primate PFC circuitry.

Action Potentials↗

PubMed1985

A new morphologically characterized cell wall preparation (whole peptidoglycan) from Bifidobacterium infantis with a higher efficacy on the regression of an established tumor in mice.

Three kinds of morphologically distinct cell wall preparations were isolated from heat-killed Bifidobacterium infantis and examined for the relative antitumor efficacy with syngeneic Meth A fibrosarcoma in BALB/c mice. Ultrastructural examinations revealed that cell wall skeleton (CWS) did not retain morphologically recognizable cell wall structure but showed fibrous structure. By contrast, a new cell wall preparation, whole peptidoglycan (WPG), which was isolated from whole cells without being subjected to physically destructive methods, completely retained the intact cell wall structure. When WPG was disrupted by sonic treatment, it retained some degree of physical integrity of cell wall structure, as compared with CWS. The results of chemical analysis indicated that the three cell wall preparations had similar chemical properties. A single s.c. injection of either CWS, WPG, or sonicated WPG in a mixture with tumor cells resulted in a significant suppression of the tumor growth. They were of equally high activity. However, when WPG, sonicated WPG, or CWS was injected intralesionally five times into mice bearing 5-day-old tumors, the incidence of complete tumor regression was demonstrated to decrease in the order of 70, 40, and 20%, respectively. The in vitro cytotoxicity test excluded the possibility that the tumor cell destruction was the result of direct cytotoxicity of the cell wall preparations. From these findings, it was concluded that WPG was an active stimulator of host-mediated response at the tumor-growing sites.

Animals↗

PubMed1999

Controlled release of human immunoglobulin G. 2. Morphological characterization.

Human immunoglobulin G (IgG) serves as an important chemotherapeutic agent for a number of immunological ailments and as a carrier in the targeted delivery of other therapeutic agents. This paper deals with the characterization of IgG-dispersed monolithic matrixes of different geometries, prepared using a nonbiodegradable polymer carrier EVAc. The morphological changes associated with the matrix during drug release was studied using scanning electron microscopy, polarizing microscopy, atomic force microscopy, and X-ray photoelectron microscopy, and the results were compared. The study answered the burst effect problem significantly and illustrated the potential of these techniques in understanding the morphological structure of matrixes and mode of release kinetics.

Delayed-Action Preparations↗

PubMed1996

Morphological characterization of polyanhydride biodegradable implant gliadel during in vitro and in vivo erosion using scanning electron microscopy.

PURPOSE: The objectives of the current study are to characterize the distribution of the chemotherapeutic agent carmustine (BCNU) in spray dried polyanhydride microspheres and to describe the morphological changes that occur during the in vitro and in vivo erosion of the polyanhydride implant--GLIADEL, which consists of BCNU distributed in the copolymer matrix of poly(carboxyphenoxy propane:sebacic acid) in a 20:80 molar ratio (p(CPP:SA, 20:80)). METHODS: Scanning electron microscopy (SEM) was used to visualize the morphological changes of the polymer during the manufacturing process and in vitro and in vivo erosion. RESULTS: This study revealed that BCNU was homogeneously distributed within spray dried polyanhydride microspheres with no phase separation. The porosity of the wafer fabricated from spray dried polyanhydride microspheres gradually increased during erosion. During the initial period following wafer implantation in the brains of rats, erosion was mainly confined to the surface layer of the wafer with the majority of the wafer remaining intact. The eroding front gradually advanced from the surface to the interior of the wafer in a layerwise fashion, creating pores and connecting channel. Eventually both the interior and exterior of the wafers were eroded and the same porous structure was seen throughout the whole wafer. CONCLUSIONS: This study provides the first visual observation of the morphological changes of the GLIADEL(R) wafer during erosion of the polyanhydride matrix and release of the drug substance BCNU. The observations in this study support the conclusion that BCNU release from a polyanhydride wafer is controlled both by diffusion of the drug and erosion of the polymer matrix.

Anhydrides↗

PubMed1991

Identification of a common cyanobacterial symbiont associated with Azolla spp. through molecular and morphological characterization of free-living and symbiotic cyanobacteria.

Symbiotically associated cyanobacteria from Azolla mexicana and Azolla pinnata were isolated and cultured in a free-living state. Morphological analyses revealed differences between the free-living isolates and their symbiotic counterparts, as did restriction fragment length polymorphism (RFLP) analyses with both single-copy glnA and rbcS gene probes and a multicopy psbA gene probe. RFLP analyses with Anabaena sp. strain PCC 7120 nifD excision element probes, including an xisA gene probe, detected homologous sequences in DNA extracted from the free-living isolates. Sequences homologous to these probes were not detected in DNA from the symbiotically associated cyanobacteria. These analyses indicated that the isolates were not identical to the major cyanobacterial symbiont species residing in leaf cavities of Azolla spp. Nevertheless, striking similarities between several free-living isolates were observed. In every instance, the isolate from A. pinnata displayed banding patterns virtually identical to those of free-living cultures previously isolated from Azolla caroliniana and Azolla filiculoides. These results suggest the ubiquitous presence of a culturable minor cyanobacterial symbiont in at least three species of Azolla.

Blotting, Southern↗

PubMed1994

Functional and morphologic characterization of thoracic aorta in heritable hyperlipidemic Yoshida rats of different ages.

We investigated serum and aortic tissue lipid content, in vitro aortic response to drugs, and morphology of thoracic aorta in Pittsburgh Yoshida rats (YOS), a new animal model of endogenous hyperlipidemia. Experiments were performed on 2-, 6-, and 18-month-old rats. Normolipidemic Brown Norway rats (BN) were used as controls. Both serum cholesterol and triglycerides increased significantly with age in YOS rats, but remained constantly low in the control group. In YOS rats, absolute serum concentration of high density lipoprotein (HDL)-cholesterol increased significantly with age, although HDL-cholesterol/total-cholesterol ratio decreased. In contrast, no difference in cholesterol content in aortic tissue was detected between the two animal strains or among different age groups. The contractile force generation of thoracic aorta to norepinephrine (NE) and serotonin increased with age in both strains of animals. The endothelium-dependent relaxation induced by acetylcholine (ACh) was significantly reduced in 6- and 18-month-old YOS as compared with 2-month-old YOS but not in BN. ATP-induced relaxation was significantly impaired in YOS thoracic aorta. In contrast, the relaxation induced by NaNO2 acting in smooth muscle did not vary with age in either YOS or BN. Only alterations in endothelial cells, not typical atheromatous injuries in thoracic aorta wall were detected in YOS even at age 18 months. Our data indicate that despite high serum lipid levels, YOS do not develop typical atheromatous lesions or functional and morphologic damage of smooth muscle cells in thoracic aorta, whereas YOS show decreased endothelium-dependent relaxation and morphologic alteration of endothelial cells.

Age Factors↗

PubMed1996

Morphologic characterization of polyvinyl sponge (Ivalon) breast prosthesis.

BACKGROUND: Although almost all breast implants are made of silicon, some implants, especially the ones used in early augmentation mammoplasty, were made of other materials, one of which is polyvinyl alcohol (commercially known as the Ivalon sponge). The morphology of this type of breast implant and its associated tissue reactions have not been characterized in detail. MATERIALS AND METHODS: A pair of polyvinyl breast prostheses implanted 40 years ago in a 66-year-old woman were removed together with their capsules to correct progressive disfiguration. The implants and capsules were radiographed. Sections from these specimens were subjected to routine histologic studies and special stains, including periodic acid-Schiff and Masson's trichrome stains. RESULTS: The breast implants were composed of crystals with a pathognomonic morphology. By hematoxylin-eosin stain, these crystals were polygonal, colorless, and refractile, but nonbirefringent, and they had a characteristic bubbling internal structure. The crystals displayed a deep-blue color with Masson's trichrome stain and were strongly periodic acid-Schiff-positive, with or without diastase digestion. These crystals appeared isolated or interconnecting and were separated from one another by spaces filled with tissue fluid. The capsules were composed of the same kind of crystals, but they were heavily calcified and associated with dense fibrosis and occasional multinucleated giant cells. CONCLUSIONS: This case serves to emphasize that breast prostheses made of materials other than silicon may be rarely encountered in the surgical pathology laboratory. Although polyvinyl breast implants were abandoned, injection of polyvinyl into various tissues for therapeutic purposes is sometimes indicated. The morphologic features of polyvinyl as detailed in this study should enable prompt and accurate recognition of this material, whether it is in breast implants or other types of tissue.

Aged↗

PubMed1992

Morphological characterization of hypersensitive human radicular dentin and the effect of a light-curing resin liner on tubular occlusion.

A dentin biopsy technique was employed to compare the morphological features of hypersensitive and non-sensitive human radicular dentin. Specimens sampled from different areas in the same root surface displaying hypersensitivity or non-sensitivity were prepared for examination in the scanning electron microscope (SEM). Before analysis some specimens were exposed to surface demineralization and digestion of collagen to allow observation of subsurface portions of the dentinal tubules. In another set of observations the potential of a light-curing resin liner to penetrate root dentin in vitro and to maintain tubular occlusion over time following treatment of hypersensitive radicular dentin were examined. Orifices of many dentinal tubules were open in hypersensitive regions while non-sensitive areas generally displayed tubules occluded with mineralized material. SEM-images of HCl-collagenase treated specimens demonstrated the frequent presence of membrane-like structures in tubules of hypersensitive dentin. In non-sensitive dentin these structures were sparse. Topical application of a light-curing resin liner to wedge shaped defects prepared in radicular dentin of extracted human teeth resulted in a surface coating with a resin thickness of 20-50 microns. Resin penetrated dentinal tubules to a depth of more than 5 microns. Dentin biopsies examined 6 months after treatment with the liner showed presence of resin-like material in a majority of the tubules in dentin where hypersensitivity was no longer perceived. In none of the specimens did the liner remain as a surface coating. In areas of recurrent hypersensitivity more than half of the tubules presented with open orifices.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Etching, Dental↗

PubMed2003

Morphological characterization of mouse B-1 cells.

At least three B cell subsets, B-1a, B-1b and B-2 are present circulating peripherally in the mouse. In these animals, B-1 cells constitute a minor fraction of B cells in spleen and are absent in lymph nodes although they represent the main B cell population in peritoneal and pleural cavities. Currently these cells are identified by a surface phenotypic repertoire; they express Mac-1, IgM(high), and B220(low). B-1a cells express CDS. The aim of this work emerged from the fact that the morphology of B-1 cells is not fully characterized. Here we identified B-1 cells using colloidal gold immunocytochemical assays and purified B-1 cells from supernatants of adherent peritoneal cell cultures by a magnetic bead technique. These techniques lead us to demonstrate that, in mice, either B-1a or B-1b cells have a unique morphology distinct from that of B-2 cells.

Animals↗

PubMed2006

Potential solution processible phosphorescent iridium complexes toward applications in doped light-emitting diodes: rapid syntheses and optical and morphological characterizations.

A series of carbazol-9-yl end-capped red-emitting heteroleptic iridium complexes was readily synthesized using post Suzuki coupling. The appealing solubility, photoluminescent characteristics, and morphological stability enabled the current heteroleptic iridium complexes to be highly desirable phosphorescent dopant emitters in doped light-emitting diodes for the purpose of resisting molecular aggregations in the doped emitting layers.

Journal Article↗

PubMed2004

Morphological characterization of Thioflavin-S-positive amyloid plaques in transgenic Alzheimer mice and effect of passive Abeta immunotherapy on their clearance.

Transgenic mice mimicking certain features of Alzheimer's disease (AD)-pathology, namely amyloid plaques and neurofibrillary tangles, have been developed in an effort to better understand the mechanism leading to the formation of these characteristic cerebral lesions. More recently, these animal models have been widely used to investigate emergent therapies aimed at the reduction of the cerebral amyloid load. Several studies have shown that immunotherapy targeting the amyloid peptide (Abeta) is efficacious at clearing the amyloid plaques or preventing their formation, and at reducing the memory/behavior impairment observed in these animals. In AD, different types of plaques likely have different pathogenic significance, and further characterization of plaque pathology in the PDAPP transgenic mice would enhance the evaluation of potential therapeutics. In the present study, a morphological classification of amyloid plaques present in the brains of PDAPP mice was established by using Thioflavin-S staining. Neuritic dystrophy associated with amyloid plaques was also investigated. Finally, the efficacy of passive immunization with anti-Abeta antibodies on the clearance of Thio-S positive amyloid plaques was studied. Our results show that distinct morphological types of plaques are differentially cleared depending upon the isotype of the antibody.

Alzheimer Disease↗

PubMed1991

Morphological characterization of rat entorhinal neurons in vivo: soma-dendritic structure and axonal domains.

We used in vivo intracellular labeling with horseradish peroxidase in order to study the soma-dendritic morphology and axonal projections of rat entorhinal neurons. The cells responded to hippocampal stimulation with inhibitory postsynaptic potentials, and thus likely received direct or indirect hippocampal input. All cells (n = 24) showed extensive dendritic domains that extended in some cases for more than 1 mm. The dendrites of layer II neurons were largely restricted to layers I and II or layers I-III, while the dendrites of deeper cells could extend through all cortical layers. Computed 3D rotations showed that the basilar dendrites of deep pyramids extended roughly parallel to the cortical layering, and that they were mostly confined to the layer containing the soma and layers immediately adjacent. Total dendritic lengths averaged 9.8 mm +/- 3.8 (SD), and ranged from 5 mm to more than 18 mm. Axonal processes could be visualized in 21 cells. Most of these showed axonal branching within the entorhinal cortex, sometimes extensive. Efferent axonal domains were reconstructed in detail in 3 layer II stellate cells. All 3 projected axons across the subicular complex to the dentate gyrus. One of these cells showed an extensive net-like axonal domain that also projected to several other structures, including the hippocampus proper, subicular complex, and the amygdalo-piriform transition area. The axons of layer III and IV cells projected to the angular bundle, where they continued in a rostral direction. In contrast to the layer II, III and IV cells, no efferent axonal branches leaving the entorhinal cortex could be visualized in 5 layer V neurons. The data indicate that entorhinal neurons can integrate input from a considerable volume of entorhinal cortex by virtue of their extensive dendritic domains, and provide a further basis for specifying the layers in which cells receive synaptic input. The extensive axonal branching pattern seen in most of the cells would support divergent propagation of their activity.

Animals↗

PubMed1988

Physiological and morphological characterization of OFF-center amacrine cells in the turtle retina.

OFF-center amacrine cells were intracellularly recorded and stained with Lucifer yellow to investigate the cell correlations between photoresponses and morphological features. All OFF-amacrine cells were monostratified and branched within the outer half of the inner plexiform layer. In the flat-mounted retina, however, three distinct morphological classes were distinguishable, which correlated with observed physiological differences. Class 1 consisted of wide-field, stellate amacrine cells with long, thin processes, which branched only close to the soma. The diameter of the circular dendritic field ranged from 0.8 mm to 2.0 mm. Their photoresponse to spot stimulation was a hyperpolarization during light-ON and a small depolarization after light-OFF. They showed strong antagonistic center-surround organization of the receptive field. Its size was approximately equal to the dendritic field size. Class 2 consisted of wide-field, giant amacrine cells with a "central" dendritic field formed by thick dendrites, and a "peripheral" dendritic field formed by a few long and thin, "axonlike" processes. The shape of the dendritic field was elongated, with the long axis parallel to the visual streak. Their receptive field size was considerably smaller than their dendritic field size, which was several millimeters of diameter along the long axis. Their photoresponse to spot stimulation was a fast depolarization after light-OFF, and about 50% of these cells showed strong antagonistic center-surround receptive field organization. Class 3 consisted of small- or medium-field, "starburstlike" amacrine cells with circular dendritic fields of 0.1 mm to 0.6 mm diameter. Their fine, beaded dendrites branched predominantly in the distal parts of the dendritic field. their photoresponses to light were similar to those of the giant amacrine cells; however, their receptive field size exceeded the dendritic field size. Radial sections of the retinas with labeled cells were incubated in antisera to reveal the putative transmitters GABA, serotonin, neurotensin, met-enkephalin and glucagon. No immunoreactivity with these antisera was detected within the stained OFF-center amacrine cells.

Animals↗

PubMed2002

Morphological characterization of cell death during the ovary differentiation in worker honey bee.

Cell death that occurs during ovary differentiation in the honeybee worker's larval development accounts for ovariole reabsorption. From a morphological standpoint, three modes of death were detected. Germinative cells in the ovarioles die by an apoptotic-like process, whereas the somatic cells die by an autophagic process, type II cell death; and during pupation, stromatic and ovarian capsular cells die through cytoplasmic disintegration, releasing their components into the hemolymph. These modes of cell death are in part determined by the pattern of tissue organization within which the cell occurs.

Animals↗

PubMed1992

Morphologic characterization and quantitative assessment of mitral regurgitation with ruptured chordae tendineae by transesophageal echocardiography.

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of morphologic characteristics and in the quantitative assessment of the severity of mitral regurgitation with ruptured chordae tendineae, 40 patients with ruptured chordae tendineae (group 1) and 20 patients with moderate or severe mitral regurgitation due to other causes (group 2) were studied. All echocardiograms were recorded before cardiac surgery. Cardiac catheterization was performed in 55 patients (92%). TEE showed greater sensitivity and negative predictive value than TTE (100 vs 65%, and 100 vs 56%, respectively; p < 0.005) in the diagnosis of ruptured chordae tendineae. Visualization of the ruptured chordae (termed snake-tongue sign) was highly sensitive and specific (93 and 95%, respectively) for establishing the diagnosis of ruptured chordae tendineae. The severity of mitral regurgitation in group 1 patients evaluated by TTE color flow mapping was underestimated by 2 grades in 1 patient and by 1 grade in 6 patients, and overestimated by 1 grade in 1 patient, compared with left ventriculography. In contrast, by TEE color flow mapping it was underestimated by 1 grade in 1 and overestimated by 1 grade in 1 patient. TEE color flow mapping showed better correlation with angiography than did TTE color flow mapping (r = 0.82 vs r = 0.49).

Adult↗