Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ultrastructure”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,747 records · Page 97Linked to original sources
PubMed1983

[Ultrastructure of the esophageal mucus glands in normal conditions and in esophageal cancer].

The ultrastructure of the glandular apparatus and epithelium of the excretory ducts of esophageal mucous glands proper normally and in esophageal carcinoma was studied electron microscopically. Acinar cells were represented by two kinds, "Dark" and "clear" cells reflecting alternating activity of the secretory cells. The ultrastructural features of the reserve cells of excretory ducts such as hypertrophy of the nucleus, scalloped nuclear membrane, high electron density of the nucleus and cytoplasm, abundance of ribosomes and polysomes allow them to be considered as low differentiated highly active cambial elements. In esophageal carcinoma, reserve cell proliferates of the excretory ducts were found to have granule-containing cells possibly related to the system of serotoninocytes. The reserve cells showed ultrastructural changes with signs of dysplasia.

Adenocarcinoma↗
PubMed1983

[Effect of chronic stress on the ultrastructure of the myocardium and hypothalamus of "emotional" and "nonemotional" rats].

The influence of chronic stress on the ultrastructure of the myocardium and hypothalamus was studied in experiments on male rats with different levels of emotional-behavioral reactivity. "Emotional" rats manifested a pronounced increase in glycogen granules in myocytes and intercellular space, appearance of the areas of overcontraction of myofibrils, conglomerates of aggregated platelets in myocardial capillaries, and red cell egress from myocardial and hypothalamic capillaries. Alterations in the ultrastructure of the myocardium and hypothalamus in "nonemotional" rats were less marked and consisted in the appearance of the areas of overcontraction of myofibrils, enlargement of sarcoplasmic reticulum caverns, and in an increase in the lipid content in cardiomyocytes. The ultrastructural changes in the myocardium and hypothalamus of "emotional" and "nonemotional" rats indicate different reactivity of the animals and are likely to be accounted for by different levels of activation of their adrenergic systems.

Animals↗
PubMed1984

[Unusual ultrastructural findings in a case of asymptomatic primary biliary cirrhosis].

The investigators report an ultrastructural study of a case of primary biliary cirrhosis histologically in stage II (Scheuer), a rare disease which has not been investigated extensively at the ultrastructural level. Biliary canaliculi are dilated and microvilli are scarce. Large granular formations are observed in the perisinusoidal cytoplasm. The plasma membrane between adjacent hepatocytes appears convoluted. The ultrastructural alterations of the biliary canaliculi which we observed have been described in the literature in cholestatic patients and ascribed to cholestasis. Our patients, however, has never suffered episodes of jaundice or itching and has no histological signs indicating cholestasis. We suggest that these are precocious alterations which precede the appearance of clinical and histological signs of cholestasis. It is necessary to study other cases in order to evaluate the significance of the large granular formations and the changes observed in the plasma membrane.

Adult↗
PubMed1984

Formation of the test in the swimming larva of Ciona intestinalis: an ultrastructural study.

The test of the Ciona intestinalis larva, before hatching, presents a single outer cuticular layer, C1. Ultrastructural observations of swimming larvae, kept in culture at 18 degrees C, show that the test is enriched by a second inner cuticular layer C2. The C2 layer begins to form in the larva immediately after hatching (about 1 h) and is a process caused by the activity of the cells of the ectodermal layer. During this phase of larval development these cells assume the typical ultrastructure of cells with secretory activity, presenting a well developed r.e.r. and a Golgi in the form of dictyosomes in active synthesis phase in the apical zone of their cytoplasm. The formation of C2 layer is complete in the larva 3 h after hatching and in this period it can be seen parallel to, and a short distance from, the plasmalemma of the ectodermal cells. In the cephalenteron region the C2 layer progressively rises towards the C1 layer and, in the larva 8 h after hatching, these two layers are very close together, about 1000 A apart. In contrast, the C2 layer in the tail remains close to the plasmalemma of the ectodermal cells and can only be detected by ultrastructural observations.

Animals↗
PubMed1984

The organum vascolosum laminae terminalis of the domestic fowl: a Golgi and ultrastructural study.

The organum vascolosum laminae terminalis (OVLT) of the fowl was studied both with the aid of the rapid Golgi method and at ultrastructural level. Small and medium-sized isodendritic neurons were observed after silver impregnation of the OVLT. Their processes often run towards the great number of blood capillaries of the organ. Small bipolar neurons were intermingled between isodendritic elements. A peculiar ultrastructural finding of the OVLT neurons was the presence of a variable amount of dense-core vesicles 90-150 nm in diameter in their cytoplasm. Numerous nerve fibers and terminals surrounded neurons, glial cells and capillaries of the OVLT. These terminals were classified into 3 main types according to the diameter of dense core vesicles observed in them. Statistical evaluations of the populations of dense core vesicles confirmed this subdivision. Type 3 terminals had ultrastructural features of monoaminergic endings, whereas type 1 and 2 terminals were probably peptidergic fibers. Neurohaemal contacts were observed. between terminals with large dense core vesicles (type 2) and blood capillaries of the OVLT.

Animals↗
PubMed1984

[Ultrastructural study of lymph node cells in experimental burn injury].

Ultrastructure of the lymph nodes was examined in rats with experimental thermal burns of the skin. Ultrastructural studies of lymph node cells demonstrated the signs of destruction at the ultrastructural level. In the authors' opinion, destructive changes in lymph node cells may form the structural basis for secondary immunological deficiency typical for burn injury.

Animals↗
PubMed1984

Analysis of methylglyoxal bis(guanylhydrazone)-induced alterations of hamster tumor mitochondria by correlated studies of selective rhodamine binding, ultrastructural damage, DNA replication, and reversibility.

Because of the renewed importance of methylglyoxal bis(guanylhydrazone) (MGBG) in recent clinical trials for a variety of cancers, and because the antiproliferative activity of MGBG cannot be accounted for exclusively by the known inhibition by the drug of polyamine biosynthesis, but is thought to involve an alternative action in which the mitochondria are implicated, we have investigated several new aspects of the nature and reversibility of this mitochondrial damage. Using Rous sarcoma hamster tumor cells as a model, treatment of monolayer cultures during exponential growth with 10, 25, and 50 microM MGBG (up to 48 hr) resulted in dose-dependent (reversible) growth inhibition and selective ultrastructural damage to the mitochondria (e.g., extreme swelling, loss of cristae and matrix components, and dense inclusions) in up to 96% of cells, while nuclei appeared normal, corroborating and extending findings by others in mouse, rat, and human cells. Mitochondria in 3 to 5% of cells failed to swell, even at highest drug dosage, but were of unusual structure. After removal of MGBG, damaged mitochondria in 90 to 95% of cells recovered near-normal ultrastructure within 1 to 2 days; in some cells, mitochondrial recovery from severe damage could be monitored following a lag period of up to 5 days. The potential-dependent, supravital fluorescent probe rhodamine 123 (RH 123) selectively and relatively uniformly stained the grossly enlarged mitochondria, strikingly delineating residual organelle membranes. Quantitative assays of the uptake and retention of RH 123/10(6) cells demonstrated the maintenance of mitochondrial membrane potential in both control and MGBG-treated cell populations. These data also support the concept of mitochondrial fusion in MGBG-treated cells. The fate of mitochondrial DNA (mtDNA) both during (24 to 48 hr) and following (7 hr to 7 days) MGBG treatment was monitored by ultrastructural, electron autoradiographic, pulse-labeling, gradient centrifugation, restriction cleavage, and electrophoretic methods. MGBG treatment (50 microM; 7 and 16 hr) selectively inhibited mtDNA replication (73% at 16 hr) prior to significant inhibition of nuclear DNA synthesis (19% at 16 hr); the drug induced structural alterations, without substantial degradation, of the closed circular (major form) of mtDNA, and cessation of D-loop strand (7S) initiation within the replication origin. Upon return to drug-free medium, mtDNA resumed replicative activity, and mtDNA fibrils appeared to be associated with regenerating cristae, as assessed by electron microscopy. The combined results demonstrate mitochondria to be a selective target of MGBG action, and define structu

Animals↗
PubMedDate not supplied

[Ultrastructure of ependymoma myxopapillare].

The results of histological and ultrastructural investigations of a tumour of the type of myxopapillary ependymoma growing initially extradurally in the end-part of the vertebral canal are reported. The patient has been observed for 13 years. During the disease several recurrences and distant metastases outside the central nervous system were observed. Histological examinations were carried out of the primary tumour and recurrences or metastases and always an evident papillary structure of tissue was found with characteristic "oedematous" stroma. In submicroscopic investigations attention was called to the stroma and to the ultrastructure of neoplastic cells. Slit-like spaces with numerous microvilli protruding into their lumen were observed between the neoplastic cells lying pallisade-like on the surface of papillae. These slits seemed on cross-sections to be minute tubular structures. This submicroscopic feature was not paid attention to in two previous papers discussing the ultrastructure of myxopapillary ependymoma.

Adult↗
PubMedDate not supplied

[Ultrastructure of skin fibroblasts in storage diseases (mucopolysaccharidosis types IV and VI)].

Ultrastructure of skin fibroblasts was studied in patients with mucopolysaccharidoses of types IV and VI and their relatives. In MPS VI and keratan-nonexcreting form of MPS IV the cytoplasm of fibroblasts contained numerous vacuoles with material of various electron density. The ultrastructure of cell did not differ from the norm in the keratan-excreting form of MPS IV. Skin fibroblasts from parents and siblings with MPS VI were found to contain a large number of residue bodies. The possible usage of ultrastructural data for early diagnosis of MPS and in medical genetic consultation of families of the patients with MPS is discussed.

Cytoplasm↗
PubMed1978

[Ultrastructural changes in the central nervous system of mice in tick-borne encephalitis].

Tick-borne encephalitis virus is localized in nerve cells and intracellular spaces. According to the nature of ultrastructural changes, the pathological process in nerve cells may be divided into three stages connected with the stages of virus reproduction. In the first stage, the protein-synthesizing systems of the cell are degraded. In the second stage specific virus inclusions form in the cell cytoplasm as aggregates of mature and immature virions alongside with destruction of ultrastructures and growth of smooth membranes. In the third stage degradation of neurons is accompanied by necrobiosis and discomplexation of the surrounding glial elements, processes, cells of the inflammatory infiltrate and capillary walls. A certain combination of nonspecific changes in organelles of various cells with viral inclusions makes the ultrastructural picture of the focus of lesions in tick-borne encephalitis sufficiently characteristic for differential pathological diagnosis.

Animals↗
PubMed1982

Ultrastructure and fatty acid composition of fatty acid-modified Morris 7777 hepatoma cells.

Morris 7777 hepatoma cells, maintained in culture for 5 days in Lewis medium supplemented with 0.1 to 0.35 mM cis-unsaturated fatty acid of the oleic (number of carbon atoms: number of double bonds, 18:1), linoleic (18:2), or arachidonic (20:4) type, were compared to similarly maintained, unsupplemented cells as to ultrastructure and fatty acid composition. The cells of unsupplemented cultures were distinguished by their spherical shape, multilobated nuclei, large nucleoli, and distribution of chromatin. Cellular extensions in the form of pseudopodia and filopodia along with junctional complexes and structures resembling bile canaliculi were evident. The cytoplasmic matrix and cellular organelles appeared normal in morphology. The ultrastructure of fatty acid-supplemented cells differed from unsupplemented hepatoma cells in cell size, location of the nucleus, abundance of endoplasmic reticulum, accumulation of lipid droplets, mitochondrial abnormalities, redistribution of cytoplasmic fibrils, and plasmalemmal extensions. Supplemented cells contained lipid droplets varying in number from a optimum of six to a maximum of greater than 70. The size of these lipid droplets varied from 0.57 +/- 0.34 (S.D.) micrometers for oleic, 1.22 +/- 0.67 micrometers for linoleic, and 0.91 +/- 0.46 micrometers for arachidonic acid-supplemented cells. Variation in the ultrastructure of supplemented cells was also evident. Cytoplasmic vesiculation appeared more frequently and was more prominent in the linoleic acid-supplemented cells. Alterations in the number of surface specializations and nuclear morphology were more pronounced in the arachidonic acid-supplemented cells. Occasional swelling, loss of matrix density, and dilated cristae were evident in mitochondria of oleic acid-supplemented cells. The neutral and phospholipid fractions of arachidonic acid-supplemented cells differed from the unsupplemented cells in the concentrations of 14:0, 15:0, 16:0, 16:1, 17:0, 18:0, 18:1, 18:2, 20:1, 20:3, 20:4, 22:5, and 22:6 fatty acids. The most significant change was detected in the higher level, 26- or 8-fold, of fatty acids 20:3 omega 6 and 22:6 in the phospholipid fraction of arachidonic acid-supplemented cells.

Animals↗
PubMed1983

Tamoxifen-induced fluorescence as a marker of human breast tumor cell responsiveness to hormonal manipulations: correlation with progesterone receptor content and ultrastructural alterations.

The fluorescent binding of tamoxifen to eosin is used on Papanicolaou-stained smears as a marker of cell responsiveness to the antiestrogen molecule. Forty-two cases of human breast carcinomas were submitted to tamoxifen treatment between first diagnosis and surgery (4 to 30 days). Tamoxifen-induced fluorescence is observed in 17 of 42 cases (40%). There is a highly significant correlation between progesterone receptor content of the tumor and cellular fluorescence (0.01 greater than p greater than 0.001). Ultrastructural changes of such tumors (820 cells observed in 28 treated patients and 840 cells in 32 untreated controls) are observed in 42% of treated cells versus 10% of untreated cells. These ultrastructural alterations can be significantly correlated with cellular fluorescence induced by tamoxifen treatment and with progesterone receptor content of human breast cancers. These data suggest that a short pretreatment with tamoxifen before surgery can give useful additional information at the biochemical, cytochemical, and ultrastructural levels regarding cell responsiveness to hormonal manipulation.

Breast Neoplasms↗
PubMed1983

Studies of experimental coronary artery reperfusion. Effects on infarct size, myocardial function, biochemistry, ultrastructure and microvascular damage.

The present report is a review of recent experimental studies in a canine model of acute coronary occlusion. The questions addressed were: (1) Does coronary reperfusion reduce myocardial infarct size? (2) What is the relationship between microvascular damage and hemorrhage and the development of myocardial necrosis? (3) What are the biochemical, functional and ultrastructural characteristics of reperfused tissue salvaged from necrosis? Coronary occlusion followed by reperfusion in the dog resulted in significant subepicardial salvage of myocardium if reperfusion was instituted before 6 hours of ischemia. Because ultrastructural evidence of microvascular damage was found only after irreversible damage to myocytes, and because gross hemorrhage after coronary reperfusion was confined to zones of myocardium that were already necrotic, it does not appear that hemorrhage should serve as a deterrent to reperfusing reversibly injured myocytes. Severely ischemic myocardium that had been salvaged by coronary reperfusion required several days before it returned to normal from biochemical, functional and ultrastructural standpoints.

Adenosine Triphosphate↗
PubMed1983

Furazolidone-induced congestive cardiomyopathy in ducklings: myocardial ultrastructural alterations.

Newly hatched male White Pekin ducklings were fed furazolidone (FZ) at dosage of 750 mg/kg of feed for 4 weeks. Selected ducklings with advanced lesions of FZ-induced congestive cardiomyopathy were used for ultrastructural study of the myocardial alterations. Semithin sections of plastic-embedded blocks of myocardium from these dilated hearts revealed diffuse myocytolysis, characterized by pale sarcoplasm and lack of cross-striations in affected myocytes. Evidence of myocardial necrosis, inflammation, or fibrosis was not observed. Ultrastructural study revealed that the principal alteration in cardiac muscle cells was diffuse myofibrillar lysis. The sarcoplasm of affected myocytes had scattered masses of free thick and thin myofilaments, clumps of Z-band material, and accumulations of cytoskeletal filaments. Numerous polyribosomes were present in the areas of lysis of contractile material, as were other normal-appearing organelles. Myofibrillar lysis may have resulted from FZ-induced decreased synthesis, increased degradation, or disaggregation of contractile proteins. Ducklings with FZ-induced congestive cardiomyopathy offer an attractive model for studies of the biochemical and ultrastructural alterations of myofibrillar lysis and drug-induced cardiac failure.

Animals↗
PubMed1983

An ultrastructural study of the marginal transitional zone in the rabbit knee joint.

The ultrastructure of the marginal transitional zone of femoral articular cartilage has been studied in the rabbit knee. There is an abrupt boundary between the convex margin of the cartilage and the synovial membrane. This is due to the arrangement and amount of collagen and of cells, because cell ultrastructure changes gradually from synovium to cartilage. The densely fibrous marginal synovium contains scattered fibrocytic cells with sparse cytoplasm and long filopodia. Near the synovium/cartilage interface, oval boundary cells containing more abundant cytoplasm abut on the cartilage matrix. In the periphery of the cartilage, an edge-belt of collagen fibrils runs obliquely from articular surface to subchondral bone. Chondrocytes near the edge-belt, whatever their depth from the articular surface, ultrastructurally resemble middle zone (zone II) cells of articular cartilage generally. The synovial surface of the marginal zone is smooth and resembles articular cartilage surfaces. Most intimal cells contain plentiful granular endoplasmic reticulum and Golgi membranes and hence are intermediate between A and B synoviocytes commonly found elsewhere. Non-fenestrated (type I) capillaries lie in a superficial stratum beneath the synovial surface and in a deep stratum near the synovium/cartilage boundary, and are surrounded by pericytes. No mast cells, macrophages, lymph vessels or nerves could be identified in the marginal zone. Contrary to earlier accounts of collagen orientation in this zone, most of the fibrils in the marginal synovium appear to run around the perimeter of the cartilage and only a few bundles run radially from the synovium towards the cartilage. It is suggested that the circumferential collagen both contains the marginal cartilage and prevents displacement of synovial tissue on to the articular surface. The radial strata of collagen serve to anchor the circumferential collagen to the cartilage edge-belt. In agreement with earlier investigators, it is considered that the edge-belt withstands tensile stresses arising from deformation of the articular surface. The role of the marginal synovium is also discussed in relation to synovial fluid formation and cartilage nutrition.

Animals↗
PubMed1982

Ultrastructure of the dermal microvasculature in leprosy.

Infection with M. leprae may lead to the presence of the organism within the dermal vascular endothelium, a phenomenon most pronounced in lepromatous leprosy. In order to study the ultrastructural features of the dermal microvasculature in leprosy, biopsies from 18 patients with lepromatous (14), borderline lepromatous (1) and borderline tuberculoid (3) leprosy were examined. Four patients with Lucio's phenomenon and four with erythema nodosum leprosum were included. The ultrastructural changes in the dermal microvasculature included endothelial swelling and hypertrophy, increased endothelial and pericytic cytoplasmic processes, and pronounced basal lamina reduplication. Occasional large, pale, endothelial cells with widely dispersed organelles were encountered. Phagocytized, membrane-bound intraendothelial organisms were found, similar in appearance to those within dermal macrophages. The predominantly perivascular dermal inflammatory infiltrate consisted of lymphocytes, macrophages and mast cells. The observed ultrastructural changes in the dermal microvasculature are similar to those previously described in the endoneurial vessels. While reflecting nonspecific responses of the dermal microvasculature in chronic inflammation, the findings support a possible role of the small dermal vessels in the chronic nature of the host's response to infection with M. leprae.

Adolescent↗
PubMed1980

Adenosquamous differentiation in mammary carcinoma: an ultrastructural and steroid receptor study.

Five breast carcinomas with only squamous morphology by light microscopy demonstrated ultrastructural features of both squamous and adenomatous differentiation within the same individual cells. Two of the five cases demonstrated quantitatively low levels of saturable estrogen- and/or progesterone-binding proteins. In no case were there quantitative or qualitative patterns of receptors indicative of clinical hormonal response potential. It is suggested that primary squamous cell carcinomas of the breast should be examined ultrastructurally for adenosquamous differentiation as each of the five apparent squamous carcinomas observed in a prospective study of 1,760 (0.3%) cases of breast cancer demonstrated adenosquamous differentiation ultrastructurally.

Adenocarcinoma↗
PubMed1980

Quantitative and ultrastructural changes of peritoneal macrophages in immunized rats after intraperitoneal injection of Novikoff hepatoma.

The response of peritoneal cells to transplantable Novikoff hepatoma was studied in immunized and nonimmunized inbred male SD rats to elucidate the role of macrophages in syngeneic tumor rejection. Specific immunization was induced by double sc challenge with viable tumor cells. Peritoneal cells were harvested by lavage at intervals of 6 hours and 1, 2, 3, 4, and 9 days after ip tumor injection. Some of the lavage fluid was used to determine the total number of cells, and the remainder was prepared for ultrastructural study. Different counts were made at the electron microscope level, and the ultrastructures of macrophages and tumor cells were studied. The results indicated that during the early intervals after tumor injection, the numbers of macrophages and lymphocytes were significantly increased in immunized animals. The mononuclear cells accumulated more slowly in the peritoneal cavities of nonimmunized rats. Morphologic heterogeneity was observed in the macrophage population of immunized rats up to day 4. Concurrent with these changes in macrophages were the decreased mitotic activity and ultrastructural alterations in tumor cells followed by their complete disappearance. In nonimmunized animals tumor cells proliferated actively and by day 9 constituted 85% of the peritoneal population.

Animals↗