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PubMedDate not supplied

Chromatin motion in interphase nuclei, its modulation and its potential role in gene expression.

Nuclear Rotation (NR) refers to the rotatory motion of nuclei in cells in vitro, a motion measured as the displacement of nucleoli over time. NR occurs in cycling cells; however, its observation in neurons indicates that mechanisms related to mitosis are not a prerequisite. We have shown that NR includes motion of chromatin domains in addition to those represented by nucleoli, that movements are saltatory, with periods of stationarity and reversal of direction. The observation that NR occurs independently of concurrent motion of juxtanuclear, cytoplasmic structures, leads to the concept of a stationary outer nuclear membrane. Although traditionally perceived as rotation in a two-dimensional plane, NR represents a complex, three-dimensional motion of chromatin within the interphase nucleus, with nucleoli and DAPI-stained, fluorescent chromatin domains describing curvilinear trajectories extending throughout the nucleus. Based upon evidence that the rate of this motion changes with metabolic demands, we have postulated that NR functions in gene expression, by transposing chromatin domains to be transcribed to specific nuclear compartments. In a test of this hypothesis, Nerve Growth Factor (NGF), which alters gene expression, increased NR at a time post-NGF coincident with increased activity of RNA polymerases, while GABA, also postulated to alter transcription, increased NR with near instantaneous shifts of nucleolar positions within the nuclear space. The calcium ionophore A23187 and the chelator EGTA, agents which redistribute calcium (Ca), also increased NR, while additional Ca, in presence of EGTA, returned NR to control rates. It is difficult to link NR with the action of agents which alter transcription or ion balance. Nevertheless, in support of our hypothesis, available evidence indicates that agents which alter gene expression, alter NR and that they do so, probably through calcium dependent mechanisms.

Animals↗
PubMed1987

[Ultrastructural labeling of the chromatoid body and the centriole-associated body using the DNase-gold colloidal complex in monkey spermatids].

In Monkey spermatids at different steps of spermiogenesis, the use of DNase-gold complex showed, at the ultrastructural level, a labeling over the chromatin and concomitantly over the chromatoid body, centriole associated body and annular chromatoid body. The results obtained with the DNase-gold complex containing either DNA or actin led to discuss the nature of the substances revealed by the labeling in the cytoplasmic structures.

Animals↗
PubMed1988

Ganglioglioma containing osseous tissue and neurofibrillary tangles.

A ganglioglioma involving the temporoparietal lobe in a 49-year-old patient displayed several unusual histopathologic features. A large central focus of osseous tissue that was found may have resulted from metaplasia of a mesodermal component of the lesion. In addition, occasional ganglioma cells showed neurofibrillary tangles and granulovacuolar changes. The presence of these cytoplasmic structures, usually seen in Alzheimer's disease and other degenerative conditions, within a ganglioglioma emphasizes the diverse settings in which such neuronal changes may occur and may provide clues to their pathogenesis.

Brain Neoplasms↗
PubMed1988

The ultrastructural features of aflatoxin B1-induced lesions in the rat liver.

Hepatocellular carcinoma was induced in rats by administering aflatoxin B1 (AFB1) for 6 weeks. Malignant tumours were preceded by foci and nodules of altered hepatocytes. The ultrastructural characteristics of the nodular lesions have been studied and compared with those of the hepatocellular carcinoma cells. Alterations in the endoplasmic reticulum, junctional complexes and nuclei were common to both the basophilic and eosinophilic nodular cells and the carcinoma cells. These most likely represent hyperplastic changes rather than malignant alterations. The eosinophilic nodules were distinguished from other lesions by the abundance of concentric, membranous whorls in the cytoplasm of nodular cells. These cytoplasmic structures were also present in some hepatocellular carcinoma cells. The observations provided further evidence suggesting that the eosinophilic nodule, rather than the basophilic nodule, may play a role in the development of malignancy in the rat liver.

Aflatoxin B1↗
PubMed1988

[Reaction of the ultrastructure of the rat spinal ganglion to exposure to a pulsed electromagnetic field].

White noninbred male rats have been subjected to a total effect of the impulsive electromagnetic field (IEMF) of 100 mT for 1, 3, 5, 10 days, 15 min daily. IEMF produces an essential morphofunctional reorganization in neurons, gliocytes, blood vessels of the rat spinal ganglion. Light neurons demonstrate an earlier reaction. Manifestation of the ultrastructural changes depends on multiplicity of the IEMF action: at initial effects they concern predominantly cytoplasmic structures of the neurons, at multiple effects--nuclear structures also become involved, reactive changes in gliocytes appear and increase. Early and distinctly seen reaction to the IEMF effect demonstrates endothelium of blood vessels. The changes revealed in the spinal ganglion are reversible, but the time of restoration of the normal ultrastructure directly depends on multiplicity of the IEMF action.

Animals↗
PubMed1987

[Indirect immunofluorescence in the serodiagnosis of Trichomonas vaginalis infections].

By using immunofluorescent technique the Authors have observed that high titer circulating antibodies reacting with membrane or cytoplasmic structures of T. vaginalis occur in the majority (42/45) of women presenting because of trichomonas vaginitis. Only exceptionally high titer antibodies have been detected in serum of male subjects affected by urethral trichomoniasis. Low titer antibodies are found in serum of noninfected subjects and are supposed to be induced by cross reacting flagellate group antigens. The contribution of these findings to a better understanding of the natural history of trichomoniasis is briefly discussed.

Adult↗
PubMedDate not supplied

[Functional state of the hepatocyte cytoplasmic network in rats with thermal burns].

Intensity of xenobiotic biotransformation estimated by means of "hexenal" test as well as enzymatic activity in liver microsomes were studied in rats with burns corresponding to impairment of 3%, 10% and 20% of body surface within 1 hr, 1, 3, 6 and 15 days. Soporific effect of hexenal was distinctly increased in the burns, which correlated to the severity of thermic impairment. Activities of amidopyrine-N-demethylase and aniline hydroxylase as well as content of protein, cytochromes P450 and b5 were decreased in liver microsomes. At the same time, lipid peroxidation was activated in microsomes, content of diene conjugates and diene ketones was increased in blood serum and in liver postmitochondrial fraction of experimental animals. Disfunction of hepatocyte cytoplasmic structures appears to be among the factors responsible for a body intoxication in burns.

Aminopyrine N-Demethylase↗
PubMed1986

Intracellular collagen in fibroblasts of Peyronie's disease.

Ultrastructural study of fibrotic plaques from six patients with Peyronie's disease disclosed collagen fibrils located within smooth membrane bound cytoplasmic structures in most of the fibroblasts. These cells also contained prominent rough endoplasmic reticulum, which was dilated and filled with electron dense material, and hypertrophic Golgi structures in which occasional collagen fibrils were seen. Vacuoles containing collagen fibrils and amorphous substance or cellular detritus were also observed. Data from the present study support the hypothesis that intracytoplasmic collagen fibril formation is caused by excessive collagen synthesis by fibroblasts of Peyronie's fibromatosis.

Cells, Cultured↗
PubMed1979

Viral infections and IgM autoantibodies to cytoplasmic intermediate filaments.

Seventy-four out of 113 sera from patients with infectious hepatitis, chickenpox, measles and mumps reacted with both smooth muscle and cytoplasmic filaments in cultured fibroblasts and neuroblastoma. Five out of eighty-five control sera also reacted in this way. That the cytoplasmic structures are intermediate filaments was suggested by their rearrangement into coils of perinuclear filaments in colchicine- or vinblastine-treated fibroblasts, but not in cytochalasin B-treated cells. The idenity of these structures was confirmed by the demonstration that the same structures reacted with the post-viral sera and a rabbit and human anti-intermediate filament antibody. Immunoabsorption studies showed that twenty-seven out of thirty-two positive sera were neutralised by skeletin, the intermediate filament protein from smooth muscle. In all but one of the sera, the antibody was IgM. Antibody titres fell in the second specimen in eleven out of fourteen pairs of acute and convalescent sera. The association between viral infections and autoantibodies suggest that production of antibodies suggests that production of antibody to intermediate filaments may be initiated by viruses.

Adolescent↗
PubMed1986

Cytochemical localization of acid phosphatase in Leishmania mexicana amazonensis.

Acid phosphatase was cytochemically detected at the ultrastructural level in infective and non-infective promastigotes and in amastigotes of the parasitic protozoan Leishmania mexicana amazonensis. Cerium chloride was used as the capture agent of the phosphate liberated during the hydrolysis of the substrate (Na-beta-glycerophosphate). Reaction product, indicative of enzyme activity, was seen in the outer face of the plasma membrane of many, but not all, infective and noninfective promastigote forms. No reaction product was seen in the plasma membrane of amastigote forms. Reaction product was seen in the endoplasmic reticulum, in the Golgi complex, in vesicles located close to the flagellar pocket and in cytoplasmic structures which may represent lysosomes. No reaction product was seen when the substrate was omitted from or sodium fluoride was added to the incubation medium. The possible role played by the acid phosphatase present in the plasma membrane of Leishmania parasites is discussed.

Acid Phosphatase↗
PubMed1979

[Electron microscopic and microbiological studies on the activity of mezlocillin against Escherichia coli (author's transl)].

Investigations by electron microscopy on thin sections and negative-stained preparations were carried out to show the effect of 6-[(R)-2-[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenyl-acetamido]-penicillanic acid sodium salt (mezlocillin, Baypen) on the ultrastructures of gramnegative bacteria (Escherichia coli C 165). Distinct alterations of the bacteria were to be seen depending on concentration and cultivation time. The outer wall of the bacterial cell became irregular. Locally it detached from the plasma membrane. The normal density of the cytoplasmic structures decreased quickly. Owing to their inability to form septa the bacteria grew as extended filaments. These mezlocillin-treated cells could form filaments of up to 100 times the length of normal untreated bacteria. Those bacterial filaments, however, were unable to form colonies as was shown by survival curves carried out in parallel. The filaments, therefore, were irreversibly damaged bacterial forms.

Escherichia coli↗
PubMed1979

[Studies on DNA content of tissues and organs. 1st communication: changes in cell content of some mesenchymal and parenchymatous rat organs during development, maturation, and in part aging (determinations of DNA) (author's transl)].

In this study the cell content was analyzed by means of the DNA content of certain mesenchymal and parenchymal organs of the rat. The main aspects were the postnatal stages of development and maturation. Their correlation to aging was examined only on examples, so was their correlation to the prenatal development (on 2 examples: liver and skin). One important result of this research is that a gradual reduction in the exponential growth takes place with increasing maturation and development. The "growth by production" prevails over the "growth by division" (of cells). This is the explanation for the "relative" (= apparent) decrease in the cell content of the tissues and organs analyzed during the decisive postnatal development and maturation phases. In this period the complete differentiation of the cytoplasmic structures and of the differentiation products of the tissues and organs here analyzed occurs. This leads to a shift in their relative amounts to the disadvantage of the cell nuclei, which prevailed in the total weight of tissues and organs during the early phases of development. This concerns determinations of the DNA content related to wet weight even more than such of the DNA content related to dry weight. As already shown clearly, the different tissues and organs of the mammalian organism (here on the example of the rat) grow, mature and age differently. During growth different phases can be distinguished, too, by analysis of the DNA content which partly correlate with phases of growth which were differentiated morphologically. Determinations of DNA contents are necessary as parameters for determinations of the production metabolism (e.g. activities of enzymes, products of formation and differentiation) of the different tissues and organs during their development, maturation and aging.

Aging↗
PubMed1980

Morphologic and histochemical analysis of hepatocytes transplanted into syngeneic hosts.

Suspensions of freshly isolated hepatocytes were prepared by collagenase perfusion of livers of adult Fischer 344 female rats. The cells were injected into the dorsal fascia of 2/3 partially hepatectomized syngeneic hosts (10(6) cells per injection site) and were monitored from 3 days to 3 months after injection. Brown nodules developed at the transplantation site. Histologic examination of the nodules revealed that the hepatocytes were arranged in cords and clusters surrounded by fibrovascular connective tissue. Bile ductules were also seen. Hepatocytes were positive for glucose-6-phosphatase. Staining for gamma-glutamyltranspeptidase showed that the parenchymal hepatocytes were mostly (approximately 95%) negative, whereas bile ductules were positive. These histochemical findings were seen in hepatocytes up to 3 months after transplantation and did not vary with the age of the transplants. Electron-microscopic examination of the transplanted nodules demonstrated that the cells maintained the characteristics of hepatocellular cytoplasmic structure. The relationship between the bile canaliculi and the stromal vessels was found to be similar to the bile canaliculi and hepatic sinusoid polarity seen in the normal liver. Autoradiographic analysis showed that a fraction of the transplanted cells was active in DNA synthesis. This system may become a tool in the study of survival and neoplastic transformation of hepatocytes as a result of exposure to X-irradiation and chemical carcinogens.

Animals↗
PubMed1984

A method for simultaneous study of the karyotype, morphology, and immunologic phenotype of mitotic cells in hematologic malignancies.

A major problem in the cytogenetic analysis of hematologic neoplasms has been an inability to identify the cell from which the chromosomes were obtained. We describe a procedure that allows simultaneous analysis of karyotype and cell cytology in mitotic cells. The method differs from conventional cytogenetic analysis in that after mild hypotonic treatment, the cells are cytocentrifuged onto glass slides. In mitotic cells, this procedure often results in adequate spread of the chromosomes within the intact cell membrane. The cytoplasmic structure also remains intact, so that cytologic preparations are of good quality. Morphologic and immunologic identification of mitotic cells can be done using routine hematologic stains, such as Giemsa or Sudan black B, and various antisera using immunofluorescence techniques. The chromosomes can be simultaneously analyzed either without banding on slides stained with Giemsa or with Q-banding on slides stained with immunofluorescence techniques. Identification of numerical and structural karyotype aberrations thus is possible in morphologically identified cells.

Aged↗
PubMed1984

Proteins closely related to spectrin and ankyrin are general components of cell membranes.

Membrane-associated analogues of erythrocyte spectrin and ankyrin have been detected in nonerythroid cells by crossreaction with antibodies. Brain spectrin and a spectrin-binding domain of brain ankyrin have been purified and demonstrated to have all known functional activities of their erythrocyte counterparts. The nonerythroid forms of spectrin and ankyrin may have functions such as providing support for the lipid bilayer, mediating some types of actin-membrane interactions, and integrating membrane-spanning proteins with cytoplasmic structural proteins.

Actins↗
PubMed1981

The mode of action of vasopressin: membrane microstructure and biological transport.

Vasopressin affects a variety of cell systems. This review is focused on permeability changes induced by vasopressin in tight epithelia such as the collecting duct of the mammalian kidney and the skin and the bladder of anurans. These vasopressin effects are discussed with reference to current concepts and models of the microstructure of the plasma membrane. The transport of three major chemical species--Na, urea and water--is analyzed. In each instance, the hormone appears to activate selective membrane pathways situated at the rat-limiting barrier of the epithelium, i.e., the apical membrane. Available data suggest that two intra-cellular messengers -- cAMP and calcium -- plan a key role in the coupling between stimulus (receptor occupancy) and biological effect (permeability change). The enhancement of Na transport (natriferic effect) depends on the opening and/or the insertion of Na channels, the biophysical and biochemical characteristics of which have been investigated by fluctuation analysis and by means of several chemical blockers of Na transport, particularly the amiloride molecule and its congeners. Likewise, the finding of inhibitors and activators of urea transport, which do not cause any appreciable change in Na or water permeability, led to the notion of selective urea channels or pores. Finally, the enhancement of water transport (hydrosmotic effect) possibly results from the insertion in the apical membrane of water channels already present in vesicular cytoplasmic structures. The restructuring of the apical membrane underlying the transition from a low to a higher state of water permeability is very likely related to the appearance of intramembrane particle aggregates detectable with the freeze-fracture technique in epithelia exposed to vasopressin. The putative water channels (or pores) appear to be so narrow that trans-apical water movement is constrained to single-file diffusion. Recent data also suggest that, in addition to cAMP, microtubules and microfilaments, the calmodulin-Ca complex is a major element in the hydrosmotic effect of vasopressin.

Amphibians↗
PubMed1984

Anti-native DNA antibodies from autoimmune sera also bind to DNA in mitochondria.

Sera from 20 patients with systemic lupus erythematosus (SLE), selected for elevated titers of antibody to native DNA (nDNA), were examined by indirect immunofluorescence (IF) on tissue culture Hep-2 and rabbit kidney cells. Twelve sera showed a particulate cytoplasmic staining, in addition to nuclear IF. Double IF staining by using a mouse monoclonal anti-nDNA and a human serum containing anti-mitochondrial antibody as probes showed that the cytoplasmic structures recognized by these 12 SLE sera were mitochondria. SLE sera showing mitochondrial staining had high anti-nDNA levels, as assessed by ELISA (3.5 +/- 1.9 O.D.), compared with those not showing this staining pattern (0.8 +/- 0.4 O.D.). Mitochondrial staining was abolished by DNase I pretreatment of the substrates. Liquid phase absorption of serum anti-nDNA with S1 nuclease-treated calf thymus DNA or purified mitochondrial DNA also removed staining. These findings demonstrate that anti-nDNA antibodies from patients with SLE bind to DNA in intact mitochondria. Therefore, mitochondrial IF staining on tissue culture cells in the presence of nuclear staining should be interpreted with caution, because the phenomenon could be entirely related to anti-native DNA. These observations might also provide new insights concerning the nature of immunogenic cellular components stimulating anti-DNA production.

Animals↗
PubMed1983

The 22 S cylinder particles of Xenopus laevis. I. Biochemical and electron microscopic characterization.

Supernatant fractions obtained after high speed centrifugation (1 h at 100 000 X g) of homogenates from whole ovaries, oocytes as well as from separated nuclei and ooplasms of Xenopus laevis contain distinct 22 S particles which have been purified and characterized by sucrose gradient centrifugation, ion exchange chromatography on DEAE-Sephacel and fast protein liquid chromatography (FPLC). The purity of the particle fraction has been assessed by electron microscopy as well as one- and two-dimensional gel electrophoresis. The particles appear as hollow cylinders of 10 nm outer diameter and 16 nm length, showing a composition of four stacked annuli which often reveal 6 symmetrically distributed granular subunits of approximately 3 nm diameter. Biochemically the particles are characterized by a group of 12 polypeptides with Mr values from 22 000 to 30 000 which in urea-denatured state markedly differ in their isoelectric values, ranging from pH 5.4 to ca. 8.2. Tryptic peptide mapping has demonstrated that all 12 major polypeptides are different. No evidence for association with nucleic acids has been found. The particles are very stable and resist treatments with low and high salt buffers, chelating agents, various non-denaturing detergents, and 3 M urea. They occur in relatively high concentrations both in the nucleus and in the cytoplasm. Structurally and compositionally identical cylinder particles have also been found in cultures of kidney epithelial cells of Xenopus and in human carcinoma (HeLa) cells, indicating that this is a rather widespread component of diverse cell types and species. The significance of this particle and its relationship to morphologically similar particles described in the literature is discussed.

Animals↗