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At least 1,621 records · Page 90Linked to original sources
PubMed1990

[The ultrastructure of the inferior olivary complex in the ground squirrel (Citellus citellus L.). Are-related changes in the dendrites].

The morphological characteristics of the elements of the neuropile in the lower olivary complex in ground squirrels at various age were studied by an electron microscope. The peculiarities in the ultrastructure of dendrite profiles, synaptic contacts on their surface and in the content of the complex synaptic connections and glomeruli. In this nuclear complex of ground squirrels--under the conditions of hibernation as well as in old very obese ground squirrels during all seasons there were a series of changes in the ultrastructure of dendrites such as: myelin-like figures, a large number of vacuoles, an accumulation of elderly pigment at the base of proximal dendrites and free postsynaptic-like condensations C. The changes in the dendrites, which occur during various functional states as well during aging, are discussed on the basis of the analysis on ultrastructural peculiarities of elements of the neuropile in the lower olivary complex in ground squirrels at various age.

Aging↗
PubMed1990

[Clinical significance of ultrastructural disorganization of cell membranes in hypotrophy].

The authors describe the results of studying lipid peroxidation and ultrastructure of blood cells in children aged 1 month to 2 years, suffering from chronic distress of nutrition of the hypotrophy type. Appreciable disorders of the membranes of blood cells and their organoids were found, related to activation of free radical lipid oxidation in diseased children. The relationship was noted between destructive changes in the ultrastructure of the biological membranes and the disease gravity, duration of the effect of the high content of lipid peroxidation products on cellular and subcellular membranes. The disorganization of the membrane ultrastructure in the body of patients with hypotrophy is an important component in the disease pathogenesis and requires administration of membrane-stabilizing therapy in a complex of treatment measures.

Cell Membrane↗
PubMed1990

[Ultrastructural changes in the erythrocytes irradiated with ultraviolet light].

The ultrastructure of erythrocytes of donor blood and blood of patients suffering from kidney insufficiency was studied with the help of scanning and transmission electron microscopes before and after it was treated with ultraviolet light. It was concluded that after being treated with ultraviolet light, the ultrastructure of donor blood erythrocytes undergoes significant positive changes which are being characterized by normalization of the form of cells, decrease of associative ties between them, the cytoplasm content becomes more homogenous. There was a noticeable increase of a number of discocytes and a decreased number of associative ties between the cells after the patients' own blood was treated with ultraviolet light. The violation of the wholesomeness of erythrocytes membrane was not discovered. The indications are that the observed therapeutical effect after treating blood with ultraviolet light, is explained, to a certain extent, by the ultrastructural modification of erythrocytes membrane.

Blood Donors↗
PubMed1990

Alteration of the erythrocyte membrane skeletal ultrastructure in hereditary spherocytosis, hereditary elliptocytosis, and pyropoikilocytosis.

The membrane skeleton of normal erythrocytes is largely organized into a hexagonal lattice of junctional complexes (JC) crosslinked by spectrin tetramers, and occasional double tetramers and hexamers. To explore possible skeletal alterations in hereditary spherocytosis (HS), elliptocytosis (HE), and pyropoikilocytosis (HPP), we have studied the ultrastructure of the spread membrane skeletons from a subpopulation of HS patients with a partial spectrin deficiency ranging from 43% to 86% of normal levels, and in patients with HPP who, in addition to a mild spectrin deficiency, also carried a mutant spectrin that was dysfunctional, thus reducing the ability of spectrin dimers to assemble into tetramers. Membrane skeletons derived from Triton-treated erythrocyte ghosts were examined by negative staining electron microscopy. HS membrane skeletons contained structural elements, consisting of JC and spectrin filaments similar to the normal skeleton. However, less spectrin filaments interconnected the JC, and the decrease of spectrin filaments attached to JC appeared to correlate with the severity of spectrin deficiency. Only in severe HS associated with severe spectrin deficiency was the loss of spectrin sufficient enough to disrupt the overall skeletal architecture. In contrast, membrane skeletons prepared from red blood cells (RBCs) of subjects with HPP were strikingly different from HS RBCs with a comparable degree of spectrin deficiency. Although HPP RBCs were only mildly deficient in spectrin, their skeletal lattice was grossly disrupted, in contrast to only mild ultrastructural abnormalities of HS membrane skeletons with a nearly identical degree of spectrin deficiency. Skeletons from patients with common mild HE or asymptomatic carriers, carrying the mutant spectrin but having normal spectrin content, exhibited a moderate disruption of the skeletal lattice. We propose that the above differences in skeletal ultrastructure may underlie differences in the biomechanical properties and morphology of HS, HE, and HPP RBCs.

Cytoskeleton↗
PubMed1990

[Parietal cell ultrastructure and acid secretory function before and after vagotomy].

Vagotomy was performed in 238 consecutive patients with duodenal ulcer since 1977. Electron microscopy of parietal cells from gastric body mucosa, gastric acid secretory test, and serum gastrin evaluation were done in randomly selected 15 PCV and 13 SV+A cases before and after vagotomy. It was found that 2-6 weeks after the surgery, the ultrastructure of parietal cells presented the feature of secretory depression and gastric acid output was decreased. One to ten years after PCV, the ultrastructure gradually regained its preoperative morphology, serum gastrin level was also increased, though acid output remained on low level. During the same period, patients undergoing SV+A were characterized with the feature of depressed secretion in gastric mucosa ultrastructure, and constantly low level of gastric acid output and serum gastrin. These results, in the authors' belief, may explain low gastric acid output after vagotomy and provide theoretical basis for the application of vagotomy in surgical treatment of duodenal ulcer.

Adolescent↗
PubMed1990

Effects of ethyl N-N-benzyl-methyl-oxamate in Meriones unguiculatus infected with Echinococcus multilocularis metacestodes. Biochemical and ultrastructural observations.

Ethyl N-N-benzyl-methyl-oxamate is a N-substituted derivative of the oxamic acid, well-known as inhibitor of the lactate dehydrogenase activity. The biochemical and ultrastructural effects of this drug in Echinococcus multilocularis metacestodes and the repercussions in the livers of receptive host, Meriones unguiculatus, were investigated. This compound decreased the specific activity of the lactate dehydrogenase in the metacestodes and the host liver by 81 and 86.8%, respectively. This N-methyl compound has shown an important repercussion on the lactate dehydrogenase activity due to its greater lipophilicity and thus allows a better penetration of the molecule. In the host liver, a fall of the alkaline and acid phosphatases activity was observed. The glucose and glycogen concentrations were also decreased. The ultrastructural study provided an alteration of the tegument of the metacestodes and damages of the muscular system. The parenchyma was disorganized. In conclusion, these biochemical and ultrastructural data obtained with ethyl-N-N-benzyl-methyl oxamate in E. multilocularis metacestodes show clearly the importance of the lactate dehydrogenase activity in the metacestodes.

Acid Phosphatase↗
PubMed1990

Ultrastructural localization of prolactin and chromogranin B messenger ribonucleic acids with biotinylated oligonucleotide probes in cultured pituitary cells.

A technique for the subcellular localization of prolactin and chromogranin B messenger RNAs (mRNA) in pituitary adenomas by in situ hybridization with biotinylated oligonucleotide probes is described. Ultrastructural examination revealed clusters and individual gold particles in the cytoplasm with this pre-embedding in situ hybridization method. Prolactinomas expressed both prolactin and chromogranin B mRNA, whereas the null cell adenoma expressed only chromogranin B mRNA. Sections of positively labeled cells contained up to 30 gold particles/cell. Treatment of cells with RNAse before hybridization reduced the number of gold particles to less than 1/cell. These results indicate that biotinylated oligonucleotide probes can be used to localize different mRNAs in cultured pituitary cells at the ultrastructural level to study the processing of these molecules within specific cells and for more precise correlation of molecular function with ultrastructural morphology.

Adenoma↗
PubMed1985

Large cell carcinoma of the lung--ultrastructural and immunohistochemical studies.

Twenty-seven cases of surgically resected large cell carcinoma of the lung including nine cases of giant cell carcinoma were examined ultrastructurally and immunohistochemically. Ultrastructurally, of 18 large cell carcinomas other than giant cell carcinoma eight showed characteristic differentiation toward adenocarcinoma, four toward adenosquamous carcinoma, and one each toward squamous cell carcinoma and neuroendocrine cell carcinoma, but the remaining four were undifferentiated. Six of the nine giant cell carcinomas also showed features of adenocarcinoma, two showed features of squamous cell carcinoma, and one was undifferentiated carcinoma. Immunohistochemically, secretory component (SC) was observed in seven of 14 cases with features of adenocarcinoma and two of four cases with features of adenosquamous carcinoma. Carcinomas with only squamous cell differentiation did not stain for SC. Keratin staining was positive in five of the 14 with features of adenocarcinoma, three of the four cases with features of adenosquamous carcinoma and two of the three cases with features of squamous cell carcinoma. The numbers of tumor cells positive for keratin and/or SC were small. One carcinoma with neurosecretory type granules was stained positively for calcitonin. These findings indicate that many large cell carcinomas showed differentiation toward glandular cells and/or squamous cells, and some did not show any differentiation ultrastructurally or immunohistochemically, indicating that the majority of large cell carcinomas are poorly differentiated form of either adenocarcinomas or squamous cell carcinomas.

Adenocarcinoma↗
PubMed1985

Histochemical and ultrastructural features of neuronal pigment in some encephalic nuclei of ruminants.

Neuronal pigment in red nucleus, locus coeruleus and substantia nigra from cattle, sheep and goat was examined with the aid of light and electron microscopy. In the red nucleus and locus coeruleus neurons of all the species examined the pigment shows the histochemical and ultrastructural features typical of lipofuscins. The ultrastructural observations indicated that the morphology of pigment granules is related to age and permitted identification of various stages of pigment evolution, which suggested a lysosomal origin of the pigment bodies. In bovine and sheep the substantia nigra is very reduced and contains no detectable pigment; while in goat, some neurons appear to contain discrete amounts of neuromelanin. Ultrastructurally this kind of pigment appears characterized by the features of a lipofuscin-like granule which stores highly electron dense material identifiable as melanin.

Age Factors↗
PubMed1985

Alterations of ultrastructure and elemental composition in cultured neonatal rat cardiac myocytes after metabolic inhibition with iodoacetic acid.

The purpose of this study was to document changes in cellular fine structure and elemental composition, and their relationship to progression of cell injury, in cultured neonatal rat cardiac myocytes in which impaired energy metabolism was produced by the metabolic inhibitor, iodoacetic acid (IAA). In order to quantitate changes in the concentrations of elements and their subcellular distribution in individual myocytes, electron probe x-ray microanalysis was performed on freeze-dried cryosections of rapidly frozen cells. After 1 hour of exposure to IAA, ATP level was not significantly reduced. Most cells exhibited minimal ultrastructural alterations and had normal elemental profiles, whereas some cells (10 to 25%) had increased sodium and calcium in mitochondria and cytoplasm. After exposure to IAA for 1.5, 2, or 4 hours, the ATP level was reduced to below one third of control, and remained decreased 24 hours after removal of IAA, indicating irreversible depression of this variable. After exposure to IAA for 1.5 hours no longer, many cells showed severe ultrastructural alterations, including contraction or swelling of mitochondria and distortion of the cristae, myofibrillar hypercontraction, and formation of fluid-filled blebs. At 1.5 and 2 hours, approximately 75% or more of the myocytes had increased sodium and calcium and decreased potassium and magnesium in mitochondria, nuclei, and cytoplasm. Thus, the development of an increased calcium concentration in cytoplasm as well as mitochondria of most myocytes was a feature of this transitional period. These data indicate that progressive alterations in the levels and distribution of elements accompany the development of severe ultrastructural changes and irreversible injury in response to impaired energy metabolism in cultured myocytes. These elemental alterations include accumulation of calcium in cytoplasm and mitochondria of myocytes in this model.

Adenosine Triphosphate↗
PubMed1986

T lymphocytic subpopulations of normal human peripheral blood defined by monoclonal antibodies: an ultrastructural study using immunogold staining method.

Submicroscopic findings of T lymphocytic subpopulations of normal human peripheral blood defined by OKT monoclonal antibodies were studied using ultrastructural immunocytochemistry (immunogold staining). The results show that OKT4-and OKT8-positive lymphocytic subpopulations have a distinct morphological pattern, although some variations in the ultrastructural details of cells in each subset are evident. The most representative features of OKT8-positive cells are regular or slightly indented nucleus with condensed chromatin, abundant cytoplasm, prominent Golgi apparatus, several granules frequently localized in the Golgi area, and numerous mitochondria, often in cluster disposition. OKT4-positive cells show generally less condensed chromatin, scanty cytoplasm and poor organule pattern. Furthermore, positive lymphocytes with prominent nuclear irregularities are found in both lymphocytic subpopulations. Ultrastructural similarities between the T cell subsets phenotypically characterized by monoclonal antibodies and other immunological criteria are also discussed.

Antibodies, Monoclonal↗
PubMed1988

Incorporation of bacterial lipopolysaccharide by human Leu-11a+ natural killer cells. Ultrastructural and functional correlations.

Lipopolysaccharides (LPS) of gram-negative bacteria are known to augment the ability of macrophages and natural killer (NK) cells to lyse susceptible target cells. In the present studies, we sought correlations between the ultrastructural changes and function of Leu-11a+ cells from the peripheral blood mononuclear cells which occurred as a result of their incorporation of LPS. We also studied the effect of LPS on the NK activity of purified Leu-11a+ cells. LPS samples from E. coli and Pseudomonas aeruginosa were utilized. A double-immunolabeling technique employing immunogold and immunoperoxidase markers was used to identify the Leu-11a+ cells with incorporated LPS. Pinocytosis, phagocytosis, and direct insertion into membrane bilayers appeared to be the routes for incorporation of LPS by Leu-11a+ cells. Subsequent ultrastructural effects included dilation of intracellular membrane compartments, formation of tubuloreticular inclusions and increased acid phosphatase activity. Opsonized Staphylococcus aureus were ingested both by control and LPS-treated Leu-11a+ cells; however, the number of Leu-11a+ cells with bacteria increased significantly as a result of LPS treatment. Autoradiography combined with immunolabeling showed no [3H] thymidine incorporation by either control or LPS-stimulated Leu-11a+ cells. NK cell-mediated cytotoxicity was significantly increased as compared with the control (p less than or equal to 0.02) when isolated Leu-11a+ cells were treated with LPS for 24 hours. This result suggests that LPS may have direct effect on the NK cell activity. Tests of peripheral blood mononuclear cell samples after LPS treatment showed up to a 2-fold increase in NK cytotoxicity and a dose-related increase of in vitro interferon production. This latter finding together with the ultrastructural observations of tubuloreticular inclusions in Leu-11a+ cells suggests that, in addition to any direct effect of LPS, cytotoxic activity could be indirectly augmented as a result of autocrine or paracrine interferon, or lymphokine production.

Acid Phosphatase↗
PubMed1989

New data on the ultrastructure of the membrane of Mycobacterium leprae.

In previous reports on the ultrastructure of Mycobacterium leprae, we described the occurrence of symmetric membranes in normal-looking bacilli from fresh or frozen samples primarily fixed with aldehydes. In those reports we admitted that such a symmetric profile, which is not found in the other normal mycobacteria, would not represent the structure of the normal membrane of the leprosy bacillus. We, therefore, re-analyzed the ultrastructure of the membrane of M. leprae. In the present work the micromorphology of the M. leprae membrane was studied by transmission electronmicroscopy after the fixation of fresh samples by OsO4 plus calcium followed by glutaraldehyde plus formaldehyde and calcium followed by uranyl acetate. The study of samples from two patients with lepromatous (LL) leprosy, three armadillos with natural leprosy, and one nude mouse with experimental leprosy showed that normal-looking bacilli present in lead-stained sections had asymmetric membranes with a thickness of 6.49 +/- 0.36 nm. These membranes showed periodic acid-Schiff (PAS)-positive components exclusively located in the outer half of the bilayer. We demonstrated that the symmetric profile of the M. leprae membrane described in our previous reports corresponds, as admitted in those reports, to an abnormal membrane structure. Such an abnormality was now found to result from the use of primary fixation with aldehydes or of samples stored frozen before fixation. These results indicate that, although ultrastructurally similar to that of the other mycobacteria, the membrane of M. leprae has a peculiar sensitivity to fixation by aldehydes. Such a characteristic, which was not found in M. lepraemurium, M. aurum, M. avium, and M. tuberculosis H37Ra, must reflect a unique membrane molecular structure, which is presently unknown.

Animals↗
PubMed1989

Ultrastructure of the Ito cells in liver disease associated with fibrosis.

The ultrastructure of Ito cells was examined in percutaneous needle liver biopsies of 36 patients. In three cases the liver was normal. Four specimens showed mild or moderate fatty degeneration. In the rest of the liver samples various types of fibrosis were seen: in four cases portal, in ten centrilobular, in eight periportal fibrosis and in five cases cirrhosis. In the normal liver Ito cells occurred not only in the Disse spaces but also in the walls of the terminal hepatic venules. In livers showing portal fibrosis the ultrastructure of Ito cells was similar to that seen in the normal liver. In the fibrotic areas of liver samples showing centrilobular or periportal fibrosis or cirrhosis Ito cells localized inside the fibrotic tissue and along the border between the connective tissue and hepatocytes. These interstitial Ito cells contained few lipid, abundant rough endoplasmic reticulum with dilated tubules filled by a flocculant material, well developed Golgi complexes and often bundles of 5 nm thick filaments with densities. These cells also known as activated Ito cells were in places surrounded by immature collagen fibrils and basement membrane fragments. There was a close contact between activated Ito cells and lymphocytes. The ultrastructure of Ito cells localizing in non-fibrotic areas did not differ from that seen in normal liver lobules. These observations suggest that Ito cells are related to fibroblasts and myofibroblasts and play an important role in the pathogenesis of liver fibrosis in humans.

Biopsy, Needle↗
PubMed1989

Effect of Reye's syndrome serum on the ultrastructure of isolated liver mitochondria.

Reye's syndrome (RS) is characterized by alterations in the ultrastructure of liver mitochondria and a generalized impairment of mitochondrial enzyme activity. Serum from RS patients impairs ATP formation and oxidative phosphorylation of isolated liver mitochondria. We examined the effect of serum from four RS patients (including mild and severe illnesses) to determine whether RS serum induces quantifiable morphometric changes in isolated liver mitochondria. RS serum expands the mitochondrial matrix (matrix = 85 to 91% of cross-sectional area, compared with 65 +/- 12% with control serum, p less than .01) and in many cases the matrix is less dense, cristae are less apparent, and mitochondrial shape is irregular. After incubation with RS serum, mitochondria are also slightly larger (range = 0.563 to 0.492 micron 2) than mitochondria incubated with serum from normal controls (0.421 +/- 0.303 micron 2). These changes are similar to those observed in vivo in RS. The effect of RS serum is largely irreversible, resembling the effect of an uncoupler of oxidative phosphorylation, and corresponds to the free fatty acid concentration in the serum, especially the concentration of serum dicarboxylic acids. Addition of comparable amounts of long chain dicarboxylic acids induces an irreversible expansion and some distortion of mitochondria comparable to that after the addition of RS serum. There is no correlation between alteration in ultrastructure and the presence of salicylates in the serum samples. The results indicate that dicarboxylic acids may play a role in the changes in mitochondrial ultrastructure that characterize RS.

Child↗
PubMed1989

[Ultrastructural characteristics of the cerebellar cortex in the postnatal development of animals with protein-calorie malnutrition and in subsequent rehabilitation].

An electron microscopical investigation of the cerebellar cortex has been carried out in mice, kept during the 10th-40th days of their life at a diet with protein insufficiency and a subsequent food rehabilitation and food rehabilitation with carnitine addition to the diet on the 41st-70th days of their life. A sharp protein limitation in the diet results in the most essential changes in the neuropil, while the ultrastructure of the piriform neurons changes slightly. Amount of the synaptic vesicles in small axonal terminals decreases and their localization in the area of the synaptic contacts changes. Simultaneously, degeneratively changed axonal terminals often occur, they demonstrate a rather electron opaque axoplasma. The food rehabilitation mainly normalizes the ultrastructure of the cerebellar cortex elements, however, in the neuropil altered axonal terminals with a high electron opaque axoplasma occur. After the food rehabilitation with carnitine addition to the diet, the cerebellar cortex ultrastructure not only normalizes, but even demonstrates certain signs of hypertrophy.

Age Factors↗
PubMed1989

Ultrastructural cytochemical analysis of oxygen radical-mediated immunoglobulin A immune complex induced lung injury in the rat.

Recent studies suggest that IgA immune complex induced lung injury in the rat is oxygen radical mediated. A cerium chloride (CeCl3) method was used to ultrastructurally analyze the in situ elaboration of H2O2 in IgA immune complex injured lungs. After induction of IgA immune complex lung injury, the lungs were instilled with a reaction buffer containing CeCl3 which forms an electron-dense precipitate when exposed to H2O2. Ultrastructural examination and x-ray microanalysis revealed electron-dense cerium deposits on the surfaces and in cytoplasmic vacuoles of alveolar macrophages located along damaged alveolar septae. Similar deposits were prominent on the luminal surfaces of injured pneumocytes, especially alveolar type II cells. No cerium-containing deposits were found in undamaged negative control lungs (IgA alone without antigen) or in lungs of rats that received IgA immune complexes in the presence of catalase. To further define the source of cerium-reactive products, monolayers of rat pulmonary alveolar epithelial cells were incubated with IgA complexes. Alveolar epithelial cells exposed to complexes produced no detectable H2O2 as measured by two spectrophotometric assays, and in the presence of CeCl3, exhibited negligible amounts of electron-dense material regardless of the presence or absence of catalase. The data corroborate indirect in vivo and in vitro studies which suggest that IgA immune complex induced lung injury is mediated by oxygen-derived metabolites produced by lung macrophages. Use of the CeCl3 method in intact rat lungs allows direct ultrastructural cytochemical analysis of H2O2 production in inflamed tissue.

Animals↗
PubMed1989

[Studies of enzyme histochemistry and ultrastructure of the myocardium in rats with streptozotocin-induced diabetes].

Experimental diabetes was induced in wistar rats by intraperitoneal streptozotocin in a single dose of 60-65 mg per kg body weight. The changes of myocardium enzyme histochemistry and ultrastructure were observed during the 2nd, 4th, 6th, 12th week of diabetic state. The glucose metabolism enzyme activities such as ICDH, SDH, MDH, LDH, all decreased. The results indicated that glucose oxidation and glycolysis reduced. In the ventricular myocardium of diabetic rats, varying degrees of ultrastructural change were apparent. Swelling of mitochondria was observed. Focal areas showed myofibrillar degeneration, and cardiac muscle muscle cells showed condensation of nuclear chromatin. Lipid droplets could be seen in the cytoplasm of cardiac myocytes. The ultrastructural changes in the cardiac muscle cells were not accompanied by any changes in the endothelial cells and smooth muscle cells of the small vessels or capillaries. This study provides a strong evidence for the occurrence of a primary myocardial disease in the model of streptozotocin-induced diabetes. The primary cardiomyopathy was not dependent on vascular pathological changes.

Animals↗