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PubMed1978

The effect of blood oxygen content and the no-reflow phenomenon on the subendocardial ultrastructural reversibility following anoxic arrest using hemodilution variables in the experimental model.

Hemodilution is an accepted modality for the conduct of cardiopulmonary bypass. The degree of hemodilution clinically employed has been in the range of 20 per cent of the initial hematocrit levels. This study was designed to evaluate the effects of hemoglobin levels and oxygen content on the reversibility of the damaged or altered ultrastructure of the endocardial layer of the ventricle and the possible role of the no-reflow phenomenon. Two series of mongrel dogs were subjected to cardiopulmonary bypass at normothermic levels and a standard period of ischemic arrest. One series was with hemoglobin levels between 5 and 10 grams (mean 7.25 grams) designated as moderate hemodilution (MH). The second series was of hemodilution with less than 5 grams of hemoglobin (mean 4.8 grams) designated as severe hemodilution (SH). The ultrastructural alteration gradient (UAG) between the epicardium and endocardium was studied with its relationship to reversibility of myocardial function and animal survival. The study demonstrated a definitive relationship between oxygen content and the reversibility of myocardial damage under normothermic conditions and anoxic arrest. The poor survival results in the SH group; two of 12 are attributed to the low oxygen availability possibly triggering the no-reflow phenomenon which prevents reversibility of the myocardial ultrastructural damage and ultimately the functional integrity of the ventricle.

Animals↗
PubMed2002

Ultrastructural analysis of brain tumors using collagen gel culture.

In an attempt to investigate the tumor type-specific ultrastructure of cultured brain tumors, a collagen gel culture was utilized instead of the conventional monolayer culture. To avoid intermingling of the normal brain cells, tumors with a clear margin and a portion typical of invasive tumors were sampled. The tumors were minced, and small fragments were prepared and embedded in the collagen gel in an aseptic manner. Tumors were observed on a daily basis under a phase contrast microscope. When sprouting of the tumor cells from a tumor fragment was confirmed, the samples were fixed with 2.5% glutaraldehyde and then processed for electron microscopy. Ultrastructurally, meningioma has been shown to form a whorl-like structure. The cell processes have a complex interrelationship, but this phenomenon cannot be regarded as the so-called interdigitation. A basement membrane was formed surrounding the tumor cell processes facing the collagen gel in two ependymomas. Lipid droplets were contained in great numbers inside a chordoma cell. These findings suggest the usefulness of collagen gel culture in analyzing the tumor type-specific ultrastructure of cultured brain tumors, and possibly in studying cellular differentiation.

Animals↗
PubMed1996

A morphological and ultrastructural study of bone in osteogenesis imperfecta.

A morphological and electron microscopic study of bone from patients with osteogenesis imperfecta (OI) has been performed. Bone from OI patients from various anatomical sites has been compared with that from normal, age-, site-, and sex-matched controls. The morphology of OI bone appeared variable among patients and sites of bone examined. Immature woven bone and a poor lamellar pattern were the significant morphological features and demonstrated that OI could not be characterized on the basis of a single histological pattern. At the ultrastructural level, a number of previously unreported features were evident. Abnormal collagen fibers and an altered mineral composition were found in many OI patients, however, the panoramic heterogeneity between clinical types and indeed within a single clinical type made it difficult to classify OI in this manner. The presence of intermitochondrial inclusions containing calcium and phosphorus and the presence of a stromal calcification in the bone in some OI patients suggested an abnormal mineral formation. Qualitatively, no obvious difference in the number of osteoblasts or osteoclasts was observed. The morphology and ultrastructure of OI bone were good indicators of the disease and serve a role in assessing the progress of a patient through diagnosis and treatment. This report presents new ultrastructural findings in collagen and in mineral formation in OI compared with normal human bone.

Actin Cytoskeleton↗
PubMed1988

Ultrastructure of matrix vesicles in chick growth plate as revealed by quick freezing and freeze substitution.

The ultrastructure of extracellular membrane-bound matrix vesicles (MVs), their biogenesis, and the surrounding matrix in chick tibial growth plate were studied after quick freezing and freeze substitution (FS) in an organic solvent. There were several notable differences in the ultrastructural preservation of cartilage when FS was used as compared with conventional fixation. The ultrastructural appearance of MVs after FS was extremely variable. Within the MVs, intravesicular filaments, amorphous material, and membrane-associated undercoat structures were observed. Intravesicular filaments, similar in diameter to microfilaments seen in the cytoplasm, were attached to the inside of MV membranes. This observation indicates the similarity of MV membranes and the plasma membrane. In some MVs in the proliferative zone an electron-dense material was present along the inner side of the MV membrane. In the prehypertrophic zone, crystalline material often appeared within the electron-dense material, which may be a precursor form of hydroxyapatite. The earliest crystals observed were in MVs but not in the extracellular matrix. Regarding MV formation, in addition to budding from cell surfaces and to cellular disintegration, this study also indicates that a sequential process of extrusion of preformed cytoplasmic structures may occur. Also, small MVs measuring 25-40 nm seem to arise from the disruption of large MVs. This is a previously unreported observation on MV biogenesis. FS preserves proteoglycans in the cartilage matrix as a fine, filamentous network. Initial extracellular calcification was not associated with this network.

Animals↗
PubMed1984

Characterization of freeze-thaw induced ultrastructural damage to endothelial cells in vitro.

The pathophysiology of endothelial cells is important to a variety of vascular conditions including coagulation and hemostasis resulting from clinical frostbite. Use of an in vitro model system demonstrated that when bovine endothelial cells were frozen at 1 degrees C or 20 degrees C/min and thawed immediately (20 degrees C/min), a variety of ultrastructural alterations occurred. Membranous structures were most extensively damaged, with mitochondria the most sensitive organelle. Low amplitude mitochondrial swelling, first evident at 0 degrees C, progressed to high amplitude swelling by -10 degrees C (frozen). In addition, the rough endoplasmic reticulum was dilated and formed large vesicles with a homogeneous matrix. Nuclear changes first occurred at -15 degrees C. These included separation and distortion of the nuclear membrane, changes in chromatin distribution, and disruption of the nucleolus. Scanning electron microscopy revealed perforated plasma membranes in some cells at -10 degrees C (frozen) and in most cells by -20 degrees C. Cultures frozen at 20 degrees C/min revealed mostly the same ultrastructural damage noted at 1 degrees C/min except a higher percentage of cells exhibited alterations. Data from the recovery index and lactic dehydrogenase (LDH) release correlated well with observed ultrastructural changes. Early swelling of mitochondria and dilation of rough endoplasmic reticulum was not lethal in the absence of freezing. Increased swelling in cytoplasmic organelles coupled with nuclear alterations at -15 degrees C resulted in a decreased survival rate and release of significant quantities of LDH by -20 degrees C. No unique morphological changes were temperature specific, but the total number of cells that displayed alterations increased as temperature decreased.

Animals↗
PubMed1986

Reaggregation of fetal rat brain cells in a stationary culture system. II: Ultrastructural characterization.

Ultrastructural characteristics of fetal rat brain cell aggregates in a three-dimensional stationary culture system are described. Transmission electron microscopy showed immature cells which developed into mature astrocytes, oligodendrocytes, and neurons during 20 d in culture. This was accompanied by the development of a neuropil where myelinated axons and synaptic complexes were observed. In addition to confirming earlier ultrastructural investigations on fetal rat brain cell aggregates, the stationary culture system also showed the presence of histiotypic regions within the aggregates. These regions consisted of ependymal cells where cilia were observed on the cell surfaces. Structures resembling subependymal basement membrane labyrinths were also observed. Macrophages seemed to be more numerous in the stationary cultures as compared to other culture systems. The stationary culture system may provide aggregates that are ultrastructurally more complex than those obtained by rotation mediated systems.

Animals↗
PubMed1990

Ultrastructural and immunohistological characterization of the SIRC corneal cell line.

A widely utilized rabbit corneal cell line, SIRC, was characterized ultrastructurally and immunohistologically. Although SIRC cells are often described as being of epithelial origin, important ultrastructural and antigenic characteristics indicate that these cells are fibroblastic and not epithelial. SIRC cells lack desmosomes, cytoplasmic filaments, and cytokeratin-structures that are characteristic of corneal epithelial cells. By contrast, the dendritic morphology, presence of vimentin, and the extensive dense accumulations of ribosomes and rough endoplasmic reticulum are consistent with a fibroblastic phenotype. Collectively, the morphology, ultrastructural features, and antigenic composition favor the hypothesis that SIRC cells are fibroblastic cells (keratocytes) and not corneal epithelial cells.

Animals↗
PubMed1978

A histochemical and ultrastructural study of stored material in neuronal ceroid lipofuscinosis.

A histochemical and ultrastructural study of five cases of neuronal ceroid lipofuscinosis (NCL) revealed the existence of two related lipopigments differing in some tinctorial properties and ultrastructure. Type I pigment is present in all the tissues affected and corresponds to the pigmentary tertiary lysosomes of well known ultrastructure. Type II pigment occurs exclusively in the neurones of lipophilic cerebral grisea, as a component of the so called protein-myoclonic bodies. It shares with type I certain basic tinctorial properties of lipopigment and its lysosomal localization, but differs in other respects. It stains poorly if at all with the PAS and PAF techniques and is markedly metallophilic, azurophilic and positive for protein. Type II pigment is extremely electron-opaque after staining with heavy metals to the extent that they appear practically amorphous. The possibility that type II material is derived from type I pigment is considered. The amount of type II pigment is highly variable. Both types of pigments are present in residual bodies of various shape and size, including spheroids.

Brain Chemistry↗
PubMed1984

Quantitative ultrastructure of cytolytic lymphocytes mediating allograft rejection in the mouse. I. Cellular alterations in T lymphocytes during specific target cell lysis.

A quantitative ultrastructural analysis of cytolytic T lymphocytes (CTL) is presented which allows both the distinction of these cells from normal T lymphocytes and permits the demonstration of ultrastructural alterations of putative CTL following interaction with target cells (TC). Alloreactive CTL were generated in C57BL/10 mice receiving intraperitoneal fibroblastic allografts and target-binding splenic lymphocytes (TBSL) were concentrated by specific immunoadsorption on fibroblast monolayers. TBSL were subjected to ultrastructural quantification either at the onset of TC interaction or following 30 or 60 min incubation at 37 degrees C. By means of simple stereological relationships it was shown that, in comparison with normal, non-cytolytic splenic T lymphocytes, TBSL were slightly larger cells, displaying around 60% more cytoplasm, a similarly-sized nucleus and approximately triple the volume of Golgi apparatus. During the first 30 min of interaction with TC, the target binding surface of the TBSL plasma membrane decreased in area. This change was accompanied by a polarization of the TBSL towards the target. Incubation of lymphocytes with TC for a further 30 min resulted in a general polarization of lymphocytic cellular constituents away from the TC. These results were only attainable by objective quantitative analysis and are discussed in relation to possible mechanisms of CTL-mediated lysis.

Animals↗
PubMed1983

Effect of bile salt perfusion and intraduct pressure on ionic flux and mucosal ultrastructure in the pancreatic duct of the cat.

Net ionic flux and mucosal ultrastructure were examined following perfusion of the cat pancreatic duct with bicarbonate or sodium taurocholate solutions (5-40 mM). Taurocholate perfusion increased net Cl- gain, net HCO3- loss and net K+ gain and was associated with significant widening of lateral intercellular spaces and increased complexity of intercellular labyrinths. Increased perfusion pressure (30 mm Hg) did not affect flux or ultrastructure during perfusion with bicarbonate but increased net ion flux significantly during perfusion with 40 mM sodium taurocholate. Ultrastructural changes during perfusion of 40 mM taurocholate at increased pressure were not consistent but focal epithelial disruption and cell shedding were seen occasionally. The hypothesis is advanced that taurocholate perfusion triggers physiological transport mechanisms and may make the duct mucosa more vulnerable to other potentially harmful agents. The significance of these changes in the pathogenesis of acute pancreatitis in man remains uncertain and care must be exercised before extrapolating from observed net ion flux data in this animal model.

Animals↗
PubMed1996

On Arachnoid Villi and Meningiomas: Functional Implication of Ultrastructure, Cell Adhesion Mechanisms, and Extracellular Matrix Composition.

Arachnoid villi or granulations are small projections of the arachnoid barrier layer into the venous sinus and its major tributaries. They are closely related to the absorption of cerebrospinal fluid, and are widely accepted to be the origin of human meningiomas. Arachnoid villi and meningiomas show a number of similarities in ultrastructure, cell adhesion mechanisms, and extracellular matrix composition. Ultrastructurally, both arachnoid and meningioma cells are characterized by interdigitations connected with junctional complexes, and extracellular cisterns related to the fluid transport. Extracellular cisterns and the intercellular space reveal abundant membrane-derived multilamellar phospholipids when a conventional ultrastructural fixative supplemented with tannic acid is used. Both arachnoid and meningioma cells are connected by Ca2+-dependent adhesion molecules: epithelial-cadherins which are concentrated at the adherens junctions. Membrane-cytoskeleton interactions by means of merlin and a-catenin molecules are thought to be crucial in signal transduction resulting in contact inhibition of cell growth in normal arachnoid cells. Impairment of these molecules might be related to meningioma-genesis. Glutathione-independent prostaglandin D2 synthase [EC 5.3.99.2] responsible for the biosynthesis of prostaglandin D2 in the central nervous system is also consistently expressed in human arachnoid villi and meningiomas. The multilamellar phospholipids are conceivably related to this arachidonate metabolism.

Journal Article↗
PubMed2004

The comparative study on ultrastructure and immunohistochemistry in AFP negative and positive hepatocellular carcinoma.

SUMMARY: To comparatively investigate ultrastructural characteristics and expressions of AFP (alpha-fetoprotein) and Tn (Thomsen-Friedenreich-related antigen) protein in AFP negative (AFP-) and AFP positive (AFP+) primary hepatocellular carcinoma. Fourty-three cases of AFP- and AFP+ hepatocellular carcinoma (HCC) tissues and five cases of normal liver tissues were divided into three groups: control group (normal liver tissue, n=5); AFP+ HCC group (the serum AFP level was higher than 10 ng/ml, n = 22); AFP- HCC group (the serum AFP level was lower than 10 ng/ml, n=21). The ultrastructural morphology was studied by transmission electron microscopy, the expressions of AFP and Tn protein were detected by immunohistochemistry and cell image analysis. 1. The immunohistochemical study showed that (1) the expression intensity and positive rate of Tn protein in AFP- HCC group were markedly higher than that in AFP+ HCC group (P<0.01); (2) The expression intensity of AFP in AFP- HCC group was lower than that in AFP+ HCC group (P<0.01). 2. The transmission electron microscopy demonstrated that some AFP- HCC cells linked closely with each other, others dispersed loosely just as cultured cells, the remarkable morphologic features in AFP- HCC cells were simple organelles, but they were abundant in the free polyribosomes. In AFP+ HCC group, all the HCC cells linked closely together and were rich organelles in their cytoplasm, especially the rough endoplasmic reticula. In addition, mitochondria and Golgi complex were obviously observed. (1) The AFP and Tn protein had discrepancy distribution in AFP- and AFP+ HCC tissues, Tn protein may be one of the early diagnostic indicators in AFP- HCC; (2) The synthetic locations of the AFP and Tn protein were different in hepatocarcinoma cells by ultrastructural observation.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed2002

Ultrastructural damage to the preserved lung and its function after reperfusion.

OBJECTIVE: This study was undertaken to clarify what damage to a lung during cold storage influenced the function of transplanted lung after reperfusion. METHODS: We examined the ultrastructural damage in preserved right lung before reperfusion, and the function of transplanted left lung, in a same dog and measured the pulmonary artery oxygen pressure after reperfusion and the wet-to-dry-weight ratio. We compared these findings between those dogs that survived until six hours after reperfusion (Alive Group) and those dogs that did not survive (Dead Group). We also investigated any correlation between the ultrastructural damage in the preserved lung and the function of the transplanted lung. RESULTS: The frequency of protrusion and destruction of the endothelial cells in the small pulmonary artery, and vacuolization of pneumocytes, in the Dead Group was significantly higher than that in the Alive Group. A correlation was found between the frequency of two kinds of ultrastructural damage; vacuolization in the endothelial cells in the small pulmonary artery and vacuolization in the pneumocytes, and the pulmonary artery oxygen pressure at 1-hour after reperfusion. A correlation was also found between the frequency of the vacuolization of pneumocytes and the wet-to-dry-weight ratio. CONCLUSIONS: Findings suggested that a lung suffering severe damage to intracellular structure during hypothermic preservation is unable to function sufficiently after reperfusion and is at high risk for early graft failure.

Adenosine↗
PubMed1994

Changes in endocrine atrial rat cardiocytes during growth and aging: an ultrastructural, morphometric and endocrinological study.

The effects of age on atrial natriuretic factor (ANF) metabolism were studied in male Sprague Dawley rats by standard radioimmunological procedures, transmission electron microscopy, and ultrastructural morphometry. Plasma atrial natriuretic peptide (ANP) levels increased during growth (1-month-old rats: 64 +/- 8.7 pg/mL; 2-month-old rats: 105 +/- 8.1 pg/mL) and did not change thereafter. Immunoreactive (ir)-ANP concentration increased significantly in senescent rats, both in the right (12-month-old rats: 254 +/- 33 ng/mg; 24 month-old: 415 +/- 77 ng/mg) and left atrium (226 +/- 30 and 498 +/- 60 respectively). The ultrastructural morphological features of the endocrine cardiocytes of senescent rats were the presence of a few lysosomal structures and atrial specific granules of higher electron-density. Ultrastructural morphometry studies did not reveal any significant increase in the number or in the mean individual volume of atrial specific granules, compared with young adult rats. In conclusion, unlike younger rats, morphometric data in older and senescent rats show that atrial granularity may not necessarily change together with atrial ir-ANP contents; ir-hormone assay findings show that senescent rats have ANP plasma levels within the norm, and a much larger hormone store in atrial tissue.

Aging↗
PubMed1995

Ultrastructural evidence of thyroid damage in amiodarone-induced thyrotoxicosis.

Amiodarone-induced thyrotoxicosis occurs in 2-12.1% of patients on chronic amiodarone treatment. In most cases its pathogenesis is related to iodine overload in the presence of preexisting thyroid abnormalities, such as multinodular or diffuse goiter or autonomous nodule. A minority of patients show apparently normal glands or pictures of non-autoimmune thyroiditis. However, there is recent evidence of a direct toxic effect of amiodarone, with consequent release of iodothyronines into the circulation. We report a patient with amiodarone-induced thyrotoxicosis with toxic thyroid effects demonstrated by electron microscopy in a fine-needle aspiration biopsy. There were three main pathologic findings: multilamellar lysosomal inclusions, intramitchondrial glycogen inclusions--both ultrastructural findings indicating thyroid cell damage--and a microscopic morphological pattern of thyroid cell hyperfunction. No inflammatory changes were found. Plasma thyroglobulin levels were high. The patient proved to be a non responder to simultaneous administration of methimazole (starting dose 30 mg/day) and potassium perchlorate (1000 mg/day for 40 days), while still taking amiodarone, thus providing evidence against a possible pathogenetic role of iodine overload. Dexamethasone (starting dose 3 mg/day) was added to methimazole. After three months euthyroidism had been restored and plasma thyroglobulin level substantially decreased. Subsequent subclinical hypothyroidism developed, which persisted after stopping antithyroid treatment and required substitution treatment with levothyroxine. In view of the primary role of lysosome function in the proteolysis of thyroglobulin molecules and of the energy-requiring carrier-mediated transport of monoiodotyrosine across the lysosomal membrane for iodine salvage and reutilization, we suggest that the pathological lysosomal and mitochondrial changes observed could be an ultrastructural marker for subsequent hypothyroidism in amiodarone-induced thyrotoxicosis. Our observations suggest the usefulness of ultrastructural thyroid evaluation and serial plasma thyroglobulin determinations to thoroughly evaluate the underlying pathogenetic mechanisms in amiodarone-associated thyrotoxicosis with apparently normal thyroid glands. Moreover, more knowledge of its pathogenesis could improve both prognostic stratification and treatment guides.

Aged↗
PubMed2001

Light responses in the green sulfur bacterium Prosthecochloris aestuarii: changes in prosthecae length, ultrastructure, and antenna pigment composition.

The morphology (mainly prosthecae length), ultrastructure, and antenna pigment composition of the green sulfur bacterium Prosthecochloris aestuarii changed when grown under different light intensities. At light intensities of 0.5 and 5 micromol quanta m(-2) s(-1), the cells had a star-like morphology. Prosthecae, the characteristic appendages of the genus Prosthecochloris, were 232 nm and 194 nm long, respectively. In contrast, when grown at 100 micromol quanta m(-2) s(-1), these appendages were shorter (98 nm) and the cells appeared more rod-shaped. Transmission electron microscopy revealed a significant decrease in the cell perimeter to area ratio and in the number of chlorosomes per linear microm of membrane as light intensity increased. In addition to these morphological and ultrastructural responses, Prosthecochloris aestuarii exhibited changes in its pigment composition as a function of light regime. Lower specific pigment content and synthesis rates were found in cultures grown at light intensities above 5 micromol quanta m(-2) s(-1). A blue shift in the bacteriochlorophyll (BChl) c Q(y) absorption maximum of up to 17.5 nm was observed under saturating light conditions (100 micromol quanta m(-2) s(-1)). This displacement was accompanied by changes in the composition of BChl c homologs and by a very low carotenoid content. The morphological, ultrastructural and functional changes exhibited by Prosthecochloris aestuarii revealed the strong light-response capacity of this bacterium to both high and low photon-flux densities.

Chlorobi↗
PubMed2002

Ultrastructural changes accompanying the mechanical deformation of bone tissue: a Raman imaging study.

Raman spectroscopy and imaging are known to be valuable tools for the analysis of bone, the determination of protein secondary structure, and the study of the composition of crystalline materials. We have utilized all of these attributes to examine how mechanical loading and the resulting deformation affects bone ultrastructure, addressing the hypothesis that bone spectra are altered, in both the organic and inorganic regions, in response to mechanical loading/deformation. Using a cylindrical indenter, we have permanently deformed bovine cortical bone specimens and investigated the ultrastructure in and around the deformed areas using hyperspectral Raman imaging coupled with multivariate analysis techniques. Indent morphology was further examined using scanning electron microscopy. Raman images taken at the edge of the indents show increases in the low-frequency component of the amide III band and high-frequency component of the amide I band. These changes are indicative of the rupture of collagen crosslinks due to shear forces exerted by the indenter passing through the bone. However, within the indent itself no evidence was seen of crosslink rupture, indicating that only compression of the organic matrix takes place in this region. We also present evidence of what is possibly a pressure-induced structural transformation occurring in the bone mineral within the indents, as indicated by the appearance of additional mineral factors in Raman image data from indented areas. These results give new insight into the mechanisms and causes of bone failure at the ultrastructural level.

Animals↗
PubMed2003

Ultrastructural and phenotypic analysis of in vitro erythropoiesis from human cord blood CD34+ cells.

Erythropoietin (EPO) induces erythropoiesis in vitro as well as in vivo, and the process of erythroid differentiation has been explored phenotypically and morphologically. However, morphological analysis of in vitro erythropoiesis of human hematopoietic progenitor cells at the ultrastructural level has not been reported before. In the present study, we have traced the ultrastructural changes of erythroid differentiation during ex vivo expansion of human cord blood (CB) CD34(+) cells in the presence of EPO by electron microscopy (EM), along with concurrent phenotypic analysis. CD34(+) cells purified from ten CBs by immunomagnetic selection were cultured in serum-free essential media in the presence of a combination of the several cytokines including EPO, thrombopoietin, flt3-ligand (FL), stem cell factor (SCF), granulocyte colony-stimulating factor, interleukin (IL)-3 and/or IL-11. Phenotypic analysis was performed by flow cytometric analysis for erythroid markers, including glycophorin C (GPC), Kell-related, glycophorin A (GPA), band 3, Lu(b), and RhD. Ultrastructural analysis was performed by electron-microscopic examination of the cultured cells stained with uranyl acetate and lead citrate. Phenotypic analysis revealed that in the absence of EPO, genuine erythroid fraction expressing the typical pattern of erythroid markers did not appear. The order of the above markers expressed in the cultured cells in the presence of EPO was GPC, Kell-related, GPA, band 3, Lu(b), and RhD, irrespective of the type of cytokine added. Of the cytokines used in combination with EPO, FL + IL-3 was the most efficient in inducing erythroid differentiation, which was followed by SCF + IL-3. EM examination demonstrated complete process of erythroid development from pronormoblasts to reticulocytes with nuclei having been extruded and mature erythrocytes. These results suggest that morphologically intact erythrocytes could be produced by ex vivo expansion of CB CD34(+) cells using EPO.

Antigens, CD34↗