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Results for “Cytoplasmic Structures”

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PubMed1985

Similarity between cytoplasmic inclusions in the paraventricular hypothalamic nucleus neurons of the turtle Mauremys caspica and the cytoplasmic structures as reaction to viral infections (hepatitis) and SIDA ultrastructural tracers.

Two types of "inclusions" observed in the neurons of the hypothalamic paraventricular nucleus of the turtle Mauremys caspica, "tubular systems" and "fingerprint-like" structures, may be added to the inventory of those described in apparently normal neurons. Despite their enigmatic significance, we are inclined to think that they could be a morphological expression of viral diseases in the neuron cytoplasm. These structures have a striking similarity with those observed on pathological cells (hepatitis and SIDA).

Animals↗
PubMed1987

Autoantibodies against cytoplasmic structures of neutrophil granulocytes in Wegener's granulomatosis.

Autoantibodies against cytoplasmic components of neutrophil granulocytes (ACPA) were detected in 18 of 32 patients with Wegener's granulomatosis (WG), but in none of the controls (n = 900), including patients with glomerulonephritis, sarcoidosis, tuberculosis, polyarteritis nodosa, and connective tissue diseases, and healthy blood donors. The presence and, to a lesser extent, the titre of ACPA correlated with the severity and activity of the disease. ACPA could be detected in only three of 11 patients with the limited form of the disease and in none in complete remission. In contrast, in all patients with active extensive disease, ACPA were present in a higher titre, and in most of the patients in partial remission (eight of 12) antibodies were demonstrable, especially in those with frequent relapses. Furthermore, the antibody titre correlated significantly with the C-reactive protein concentration (P less than 0.05), but with none of the other laboratory parameters. In conclusion, ACPA have proven to be a highly specific disease marker of great clinical significance that provides us with a useful tool to confirm, or even establish. the diagnosis of WG.

Adult↗
PubMed1977

A quantitative analysis of the incidence of certain cytoplasmic structures in the ovum of the rat during cleavage.

The volumetric density of most cytoplasmic organelles in the segmenting ovum of the rat was determined by morphometric techniques described by Weibel, at the 1-, 2-, 4-, and 8-cell stages, and at the early and late blastocyst stages. During the course of cleavage, the volumetric density of mitochondria remained practically unchanged. The volumetric density of the Golgi complex complex was too small to permit assessment of the differences between the individual stages of development. Significant changes were found in both granular and agranular endoplasmic reticulum, secondary lysosomes, multivesicular bodies, lamellar structures and lipid droplets. Granular endoplasmic reticulum was first observed as late as the 8-cell ovum stage and its volumetric density increased further in the early and late blastocysts. The relative volume of agranular endoplasmic reticulum was highest in the 1-cell ovum and decreased during the course of cleavage. The same is true for multivesicular bodies. The volumetric density of secondary lysosomes increased during cleavage, reaching the highest values in the 8-cell ovum. Lamellar structures were the most voluminous part of the cytoplasm of the segmenting ovum at all stages. Their volumetric density, however, decreased during the course of cleavage. Lipid droplets occur in very small quantities in the 1- to 4-cell ova, but at later stages their volumetric density increased. Our findings underline the importance of acquiring quantitative information about changes in cell organelle populations for assessing morphological and functional relationships during the early stages of cleavage of the ovum.

Animals↗
PubMed1997

A novel cytoplasmic structure containing DNA networks in Entamoeba histolytica trophozoites.

We report here the presence of cytoplasmic DNA arranged in networks in the trophozoites of the human parasite Entamoeba histolytica. Cytoplasmic DNA was detected in live trophozoites in a structure that we called EhkO, using the fluorescent dye acridine orange, and by in situ hybridization to trophozoites with a rDNA probe. The EhkO was found in the axenically grown clones A, L6 (strain HMI:IMSS) and MAVax (strain MAV) and in the polyxenically grown clone MAVpx (strain MAV). Bacteria present in MAVpx did not cross hybridize with the DNA probe neither in in situ hybridization or in Southern blot experiments. Autoradiography of metabolically [3H]thymidine-labeled trophozoites showed the presence of EhkO, and an EhkO-enriched fraction, purified from a nuclei-free extract and examined by light microscopy, exhibited [3H]thymidine incorporation into this structure. DNA was purified from the EhkO and enriched nuclear fractions and analyzed by transmission electron microscopy. The EhkO fraction contained DNA networks resembling those of trypanosome kDNA, whereas nuclear DNA was present mainly as linear molecules and some circles. Our findings imply that E. histolytica may be taxonomically more closely related to the Trypanosomatidae than previously suspected.

Animals↗
PubMed1976

Polarization microscopic evidence for an oriented cytoplasmic structure in the "dark" variants of adrenalin-storing cells.

A diffuse cytoplasmic birefringence confined to "dark" adrenalinstoring cells has been described. The main optical characteristics of the birefringence factor include: regular orientation of birefringence relative to the base-apex axis of cells; additive anisotropic staining with methods based on the principle of topo-optical staining reactions; dependence of birefringence on labile morphologic properties. On the basis of the capacity of the macromolecular matrix of chromaffin granules to form lamellar liposomal structures in vitro it has been proposed that a reorientation of molecular organization in the matrix of chromaffin cells is responsible for the observed optical phenomenon. The direction of birefringence was explained by a preferential direction of contractile forces acting during "dark" cell formation.

Adrenal Medulla↗
PubMed1968

Replication of Western equine encephalomyelitis virus. II. Cytoplasmic structure involved in the synthesis and development of the virions.

Analysis of the cytoplasmic fraction of chick embryo cells during the exponential phase of Western equine encephalomyelitis (WEE) virus growth showed that the viral ribonucleic acid (RNA) labeled by a short pulse with (3)H-uridine was associated with a structure which sedimented in sucrose density gradients with a coefficient of 65S. The RNA extracted from this structure sedimented in sucrose density gradients at 26S. After a longer period of exposure to (3)H-uridine, the radio-active viral RNA was associated with a structure which sedimented in sucrose density gradients as would materials with coefficients of about 140S. The 140S structure contained viral RNA and viral protein. It was shown that the 140S structures are not virus-induced polysomes. The 140S structure contained predominantly the 40S type of viral RNA and some 26S type. Electrophoretic analysis of the disrupted virion revealed that at least two proteins (types I and II) were present in the purified virion. Only type II protein was present in the 140S structure. Unlike the virion, the 140S structure did not contain any lipid which could be detected by the incorporation of (14)C-choline. These data suggest that the 140S structure represents the internal nucleoprotein part of the virion. The rate of appearance of labeled virus lags behind that of the formation of the 140S structure in infected cells. Pulse-chase experiments with (3)H-leucine suggest that the 140S structure may represent a precursor to the virus particle. The results are discussed in terms of the maturation of WEE virus in the infected cells.

Acrylates↗
PubMed1982

Quantitative zonal analysis of cytoplasmic structures of growth-plate chondrocytes in vivo and in vitro.

The cytoplasmic components of chondrocytes from the various zones of the rat costochondral junction, grown in vitro, were quantitated from electron micrographs using a point-counting technique, and the results were compared statistically with the cytoplasmic components of chondrocytes in the corresponding zones of the junction in vivo. Detectable changes occurred in vitro as early as after six hours of culture. The major changes that occurred in vitro were: an increase in the amount of lipid bodies in chondrocytes in the hypertrophic zone and in the bottom portion of the proliferative zone, failure of the chondrocytes in the bottom portion of the hypertrophic zone to increase in size, retention of intactness of the cell membrane of chondrocytes at the base of the hypertrophic zone, a decrease in the number of mitochondria in chondrocytes in the hypertrophic zone and in the middle and bottom portions of the proliferative zone, and a decrease in the number of holes in the cytoplasm of chondrocytes in the bottom one-half of the hypertrophic zone. In vitro hypertrophic chondrocytes of the growth plate demonstrated cellular changes associated with aging, while in vito the hypertrophic chondrocytes demonstrated changes associated with degeneration. The final result in both cases was cell death.

Aging↗
PubMed1992

Location of the basal disk and a ringlike cytoplasmic structure, two additional structures of the flagellar apparatus of Wolinella succinogenes.

The basal body of Wolinella succinogenes consists of a central rod, a set of two rings (L and P rings), a basal disk from 70 to 200 nm in diameter, and a terminal knob. In negatively stained preparations of flagellar hook-basal body complexes, some disks remain fixed perpendicularly to the grid and show that such a disk is located on the distal side of the P ring. The basal disks have been isolated with and without the P ring; in both cases there is a hole in the center of the disk. The diameter of the disk is smaller in the presence of the P ring. The L-P ring complex is therefore assumed to be a bushing for the rod. Thin sections of whole bacteria and spheroplasts reveal that the disk is attached to the inner surface of the outer membrane. At the insertions of the flagellar hook-basal body-basal disk complexes, depressions are visible in negatively stained preparations of whole bacteria and spheroplasts. A new ringlike structure is connected to an elongation of the basal body into the cytoplasm in both preparations. Its diameter (60 nm) is larger than that of the M ring. A heavily stained compartment can be seen in between the new ringlike structure and the basal disk, which may be formed by the energy transducing units.

Cytoplasm↗
PubMed1992

Ultrastructural and morphometric analysis of cytoplasmic structures in preimplantation pig embryos.

Preimplantation pig embryos (1-, 2-, 3/4-, 16-cell stage, blastocysts) were analysed morphologically and/or morphometrically by means of electron microscopy and computer-assisted image analysis. Qualitative and quantitative changes in localization, organization, number, and area of cytoplasmic inclusions were analysed on thin sections. The structure and number of mitochondria, number of endoplasmic reticulum profiles were recorded in several individual developmental stages. Three types of cytoplasmic inclusions were described (vesicles with yolk globules, vesicles with homogeneous light inclusions, lipid droplets), each having a different topographic distribution. Quantitatively, a gradual increase in the number of endoplasmic reticulum profiles and mitochondria occurred between 4-cell stage blastomeres and blastocyst trophectoderm cells. The significant differences recorded in number, morphology and distribution of organelles in different embryonic developmental stages are discussed in relation to physiological phenomena known to occur during cleavage and compaction.

Animals↗