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PubMed1978

In vitro studies on Borna virus. I. The use of cell cultures for the demonstration, titration and production of Borna virus.

Borna virus produces non-lytic infections in a wide spectrum of primary cell cultures and cell lines. The sensitivity and virus yields vary with the different cell systems. Accurate virus titrations can be performed in the RK 13 cell line by counting immunoflourescent microfoci between the 5th and 10th day after infection. Since the virus is not released from the cells and does not spread via the culture medium, the use of a semisolid overlay in unnecessary in virus titrations. The cell line most productive for Borna virus is the CV 1 line. The conditions for optimum virus production include a prolonged cultivation period of at least two weeks with regular changes of medium, and an incubation temperature of 35 degrees C. Harvest of the virus requires thorough disruption of the infected cells, preferably by ultrasonication, since Borna virus seems to be closely associated with cellular structures.

Borna disease virus↗
PubMed1993

Unusual hepatocellular lesions in primary biliary cirrhosis resembling but unrelated to hepatocellular neoplasms.

Structural, cellular and nuclear abnormalities of hepatocytes are a histological hallmark of well-differentiated, small hepatocellular carcinoma (HCC) or its borderline lesion. This study revealed that several hepatocellular abnormalities found in these hepatocellular neoplasms were also found in non-cirrhotic stages of primary biliary cirrhosis (PBC) in which HCC is unlikely to develop. These changes are small cell changes, consisting of the appearance of small hepatocytes arranged in thin trabecular or compact patterns with increased cellularity and basophilic cytoplasm. This was found in 36%, 71% and 100% in specimens of stages 1, 2 and 3, respectively. Large cell changes occurred and consisted of large hepatocytes with large nuclei and prominent nucleoli, found in 27%, 47% and 22% of the stages, respectively. Finally, liver cell rosettes were seen, showing variable acinar formation and present in 0%, 41% and 33% of the stages, respectively. These lesions were identified microscopically as irregularly shaped areas or vague nodules of hepatocytes without a fibrous rim, in the hepatic lobules. They showed an expansive growth or shaggy border against the surrounding hepatic parenchyma. Follow-up studies, including autopsies, failed to show development of HCC or its borderline lesion in PBC cases. Pathologists must make a diagnosis of HCC and its borderline lesion bearing in mind the occurrence of such unusual hepatocellular lesions probably of a reactive nature.

Adult↗
PubMed1976

Enzyme defense against reactive oxygen derivatives. II. Erythrocytes and tumor cells.

The enzymatic destruction of oxidizing products produced during metabolic reduction of oxygen in the cell (such as singlet oxygen, H2O2 and OH radical) involves the concerted action of superoxide dismutase-which removes O-2 and yields H2O2-and H2O2 removing enzymes such as catalase and glutathione peroxidase. A difference in distribution or ratio of these enzymes in various tissues may result in a different reactivity of oxygen radicals. It was found that in red blood cells superoxide dismutase and catalase are extracted in the same fraction as hemoglobin, while glutathione peroxidase appears to be "loosely" bound to the cellular structure. This suggests that in red blood cells catalase acts in series with superoxide dismutase against bursts of oxygen radicals formed from oxyhemoglobin, while glutathione & peroxidase may protect the cell membrane against low concentrations of H2O2. On the other hand, catalase activity is absent in various types of ascites tumor cells, while glutathione peroxidase and superoxide dismutase are found in the cytoplasm. However, the peroxidase/dismutase ratio is lower than in liver cells, and this may provide an explanation for the higher susceptibility of tumor cells to treatments likely to involve oxygen radicals.

Acetylcholinesterase↗
PubMed1987

Arrest of proteolipid transport through the Golgi apparatus in Jimpy brain.

Immunocytochemical investigations were performed on Jimpy and control mouse brains using three specific anti-myelin proteolipids antisera: immunoaffinity purified multivalent anti-(PLP + DM-20) proteolipid antibodies, anti-C-terminal hexapeptide 271-276 and anti-tridecapeptide 117-129 antisera. The results show that oligodendrocytes and myelin sheaths in normal mouse brain are labelled to the same extent by the three specific antisera; in contrast, in Jimpy brain these cellular structures are only stained by the multivalent antibodies and the site-specific, anti-tridecapeptide antiserum. The absence of labelling with C-terminal hexapeptide antiserum in mutant brain is interpreted as the result of either a large deletion or a point mutation producing a frameshift in the C-terminal part of the sequences of the proteolipids PLP and DM-20. Furthermore, we show that this mutation prevents the normal transport of proteolipid molecules through the Golgi apparatus. The existence of a minor, extra-Golgi apparatus metabolic route for proteolipids to myelin structures is also discussed.

Animals↗
PubMed1989

Altered cytokeratin expression and differentiation induction during neoplastic transformation of cultured rat liver cells by nickel subsulfide.

Rat liver T51B cells were maintained in the presence of low concentrations of Ni(II) derived from alpha Ni3S2 for 3-15 months in culture in order to monitor cytokeratin, differentiation, and transformation patterns. Nickel exposures caused irreversible, heritable juxtanuclear aggregates of cytokeratin CK55, which increased in size and complexity with prolonged nickel exposure, eventually resembling Mallory bodies and expressing glutamyltransferase. Altered cytokeratin expression was accompanied by induction of differentiation, with markers of both bile ductular cells and hepatocytes, such as induction of cytokeratin polypeptides CK39 and CK49, cell morphology, and cytokeratin filament network changes; whereas control cultures similarly maintained for long periods in culture remained unchanged. Altered cytokeratin expression was also accompanied by acquisition of transformation markers--loss of density dependence, progression toward calcium independence, and (benign) growth in nude mice. Observed cytokeratin aberrations may be a factor in nickel carcinogenesis, in view of the known affinity of the metal for cellular structural proteins, especially keratin, which play a role in maintenance of cell behavior.

Animals↗
PubMedDate not supplied

Elementary events in excitation-contraction coupling of the mammalian myocardium.

Excitation-contraction coupling of the mammalian myocardium is widely assumed to comprise the following chain of events: (1) Influx of Ca++ into the cell during the plateau phase of the action potential as well as Ca++ release from the subsarcolemmal cisternae of sarcoplasmic reticulum. (2) Activation of the contractile proteins by interaction of Ca++ with the troponin-tropomyosin system. (3) Relaxation due to reuptake of Ca++ by the sarcotubular system as well as by pumping of Ca++ out of the cell through the surface membrane and the transverse tubular system. (4) Movement of Ca++ in the longitudinal tubules back to the subsarcolemmal cisternae. A short comment is included about the effects of hypertrophy on the excitatory processes as well as on cellular structural constituents directly involved in excitation-contraction coupling.

Action Potentials↗
PubMed1989

The modulation of astrocytic differentiation in cells derived from a medulloblastoma surgical specimen.

Medulloblastomas are cerebellar tumors which are primarily composed of sheets of uniform, small malignant cells and may have astrocytic, neuronal or no features typical of these cell types. The assessment of astrocytic differentiation in medulloblastoma rests largely on the detection in malignant cells of glial fibrillary acidic protein (GFAP), a marker present in the later stages of normal astrocyte differentiation. It is still not known whether cells that do not contain GFAP in medulloblastomas with astrocytic differentiation correspond to highly proliferative astrocyte progenitors in maturation arrest at earlier stages of differentiation. The purpose of the current study was to examine whether cells in short term culture derived from a medulloblastoma tumor specimen with astrocytic differentiation were of the astrocytic lineage and if so, whether they represented proliferative astrocyte progenitors which would morphologically and antigenically mature in response to differentiating agents. A portion of tumor specimen from a 10-month-old child with recurrent posterior fossa medulloblastoma (RB2) that contained GFAP focally in tumor cells was grown in monolayer culture. We examined cellular structure and appearance of western immunoblotting and immunohistochemical studies for GFAP and neuron-specific enolase (NSE) in RB2 cells before and after treatment with retinoic acid (RA) and dibutyryl cyclic AMP (dBcAMP). RB2 in culture consisted of small polygonal cells (93%), large flat cells (3%), and polygonal cells with cytoplasmic processes (4%). In untreated RB2, 30% of cells expressed GFAP and staining for NSE was negative. RA treatment produced flattened cells and decreased GFAP. DBcAMP reversibly induced fine cytoplasmic processes containing GFAP in 85% of cells within 96 h. Neither agent induced NSE. The results suggest that cultured cells which are derived from a medulloblastoma with astrocytic differentiation do not spontaneously differentiate but that treatment with dBcAMP suppresses proliferation, enhances cytoplasmic process formation and increases cytoplasmic GFAP. Cells in culture and in medulloblastoma tumor specimens which do not contain GFAP may represent astrocyte progenitors in maturation arrest.

Astrocytes↗
PubMed1989

Metabolic and anatomic development of the chick embryo as studied by phosphorus-31 magnetic resonance spectroscopy and proton MRI.

Thirty fertilized chick eggs were studied sequentially over the 22-day maturation period of the egg by phosphorous-31 (P-31) magnetic resonance spectroscopy (MRS) and proton (H-1) magnetic resonance imaging (MRI) at 2.0 Tesla. The total MR observable P-31 volume in the egg decreased by nearly 80% from day 4 through day 22, suggesting P-31 uptake into tissues in which the P-31 signal is not visible by MR, such as phospholipid bilayers, membranes, cellular structures, and bone mineral phosphates. Of the remaining visible phosphates, the relative phospholipid peak area decreased and the relative peak areas of the phosphocreatine and nucleoside di- and triphosphate metabolites increased. Inorganic phosphate also showed an increase in peak area during maturation. The metabolic development correlated with the anatomic development of visible structures such as brain, eyes, spine and organs in the chick as seen by MRI. In-vivo MR techniques offers the potential to follow changes in prenatal development and maturation.

Adenosine Triphosphate↗
PubMedDate not supplied

Morphochemical features of sensorimotor cortex and neostriatum neurons in rats with different levels of alcohol preference.

This paper reports interferometric studies of the contents and concentrations of proteins in the cellular structures of neurons of the sensorimotor cortex (layers III, V) and in the region of the caudate nucleus of the neostriatum (Golgi type II cells) in Wistar rats with high, intermediate, and low levels of ethanol preference. The greatest differences between groups of animals in terms of cell size and protein metabolism were seen in the cortex. Along with measures correlating with initial ethanol preference (cell body size, nucleus size, and cytoplasm size of cortical neurons, cytoplasmic protein content, etc.), a number of measures were found to show statistically significant differences which did not correlate with preference (nuclear protein contents and concentrations in cortical neurons of layers III and V). These data may suggest the existence of another significant measure responsible for the difference between the groups and, possibly, more closely correlated with the analytical-synthetic functions of the central nervous system.

Alcohol Drinking↗
PubMed1996

Applications of immunogold and lectin-gold labeling in tumor research and diagnosis.

Immunohistochemistry and carbohydrate histochemistry have had an enormous impact on both tumor research and diagnosis. In particular, immunogold labeling has provided significant advantages over classical fluorescence and enzyme-based techniques. In light microscopy, the silver-intensified gold labeling has proven highly sensitive and precise in localization. In electron microscopy, the gold particle marker was a prerequisite for successful and unequivocal antigen detection in electron-dense cellular structures such as secretory granules. In this review we demonstrate the usefulness of light and electron microscopical gold labeling techniques as applied in tumor research and diagnosis. The examples include expression of beta-1,6 branches and specific sialoglycoconjugates in colon carcinoma, b-12 carbohydrate epitope in breast carcinoma, polysialic acid in neuroendocrine tumors of lung, adrenal and thyroid, as well as studies on proinsulin to insulin conversion in insulinomas. In addition, practical hints for prevention of background staining, tissue fixation, and silver intensification of gold labeling are given.

Animals↗
PubMed1975

Growth, respiration and cytology of acetate-negative mutants of Candida albicans.

A number of acriflavine-induced mutants of Candida albicans, characterized by their inability to grow on acetate as a source of energy, were screened for their cytochrome absorption spectra. Three mutants with different spectra, along with their parent, were selected for comparative studies of their growth, respiratory activities and cellular structure. The spectrum of one of the mutants was the same as that of the wild-type, but the growth rate and yield of cells on glucose medium were only about 60% of the wild-type's; those of a second mutant deficient in cytochromes aa3 were 50%, and those of a third mutant deficient in cytochromes aa3 and b were less than 5% of those of the wild-type. The cytochrome-complete mutant and the wild-type showed respiratory activity both on glucose and ethanol well above the endogenous, the cytochrome aa3-deficient mutant showed only endogenous respiration, and the cytochrome aa3, b-deficient mutant no respiration at all. Electron microscopy of the wild-type cells revealed discrete, regular ovoidal, cristate mitochondria spaced near the periphery of the protoplasm; the cytochrome-complete mutant showed an abundance of large, cristate, but morphologically irregular mitochondria; the cytochrome aa3-deficient mutant had fewer but still large, cristate, somewhat irregular mitochondria; and the cytochrome aa3, b-deficient mutant only a few simple vesicles without discernible cristae.

Acetates↗
PubMed2006

Proteomic analysis in cancer research: potential application in clinical use.

The ultimate goal of cancer proteomics is to adapt proteomic technologies for routine use in clinical laboratories for the purpose of diagnostic and prognostic classification of disease states, as well as in evaluating drug toxicity and efficacy. The novel technologies allows researchers to facilitate the comprehensive analyses of genomes, transcriptomes, and proteomes in health and disease. The information that is expected from such technologies may soon exert a dramatic change in cancer research and impact dramatically on the care of cancer patients. Analysis of tumor-specific proteomic profiles may also allow better understanding of tumor development and the identification of novel targets for cancer therapy. The localization of gene products, which is often difficult to deduce from the sequence, can be determined experimentally. Mechanisms, such as regulation of protein function by proteolysis, recycling, and isolation in cell compartments, affect gene products, not genes. Finally, protein-protein interactions and the molecular composition of cellular structures can be determined only at the protein level. The biological variability among patient samples as well as the great dynamic range of biomarker concentrations are currently the main challenges facing efforts to deduce diagnostic patterns that are unique to specific disease states. While several strategies exist to address this problem, we have tried to offer a wide perspective about the current possibilities.

Antibodies, Neoplasm↗
PubMed1996

Monoclonal antibodies against human chondrocytes.

Cell-specific antigens are mainly found in cells or membrane surfaces rather than in the surrounding matrix. However, until now it was not possible to produce antibodies specific for cellular structures of chondrocytes. In 1989, Lance (Immunol. Lett. 21:63-73; 1989) first established specific monoclonal antibodies for human articular chondrocytes tested only by immunofluorescence. Studies describing the specificity of these five antibodies (HUMC 1-5) and their relevance for immunohistological analysis of cartilage tissue were not available until now. Therefore, the aim of the following study was to investigate the distribution of HUMC 1, 2, 3, 4, and 5 in mesenchymal cells in vivo and in vitro immunohistochemically. Further investigations concentrate on the localization of chondrocyte specific antigens using immunoelectron microscopy. Immunohistological studies showed positive immunostainings with all five antibodies in human chondrocytes in vivo and in vitro. A cross-reaction with human fibroblasts and osteoblasts for the antibodies HUMC 2 and HUMC 5 was observed. Furthermore, a parallel loss of immunoreactivity for HUMC 1, HUMC 3, and HUMC 4 was observed in cultured chondrocytes indicating that the specific antigens vanish during differentiation observed in vitro. Subsequent immunoblot analysis employing collagens as antigens did not show any reactivity. Using immunoelectron microscopy, gold particle labeling was observed in intracytoplasmatic vesicles of isolated chondrocytes. Our results indicate that HUMC 1, HUMC 3, and HUMC 4 are specific for cartilage cells and might be suitable for immunohistological analysis of different cartilage tissues and pathologically altered chondrocytes.

Antibodies, Monoclonal↗
PubMed1998

Halofuginone inhibits neointimal formation of cultured rat aorta in a concentration-dependent fashion in vitro.

Halofuginone, an anticoccidial quinoazolinone, can specifically inhibit collagen type alpha1 (I) synthesis and gene expression, and also inhibits cultured smooth muscle cell proliferation. The aim of this study was to investigate the effect of halofuginone on neointimal formation of rat aorta after culture in a concentration-dependent manner in vitro. Thoracic aorta of Wistar rats was removed and manipulated to damage the endothelium under sterile conditions, and culture for 15 days in halofuginone-free or halofuginone-added culture medium (n = 20). Segments of cultured aorta were studied by histologic and immunohistochemical methods. Proliferation of neointimal layers consisting of loose multilayer cellular structure was observed in the halofuginone-free control group after 15 days of rat aorta culture, and neointimal formation was significantly decreased as an increasing concentration of halofuginone was added. As with precultured fresh aorta, no intimal proliferation was observed in the cultured segments of aorta with 500 ng/ml halofuginone added to culture medium. The proliferation of cell nuclear antigen index was significantly higher in the halofuginone-free control group than that in the halofuginone-added groups. The present results suggest that halofuginone can inhibit neointimal formation of rat aorta after culture in a concentration-dependent fashion in vitro.

Animals↗
PubMed1992

Ultrastructural and autoradiographic study of preimplantation rabbit embryos grown in conventional or uterine flushing-supplemented culture media.

Rabbit morulae and blastocysts were cultured in conventional culture media [Ham's F10 or BSM II supplemented with bovine serum albumin (BSA) or serum] or in Ham's medium supplemented with synchronous or asynchronous uterine flushings, mostly for 2 days, and afterwards investigated by light and electron microscopy and by autoradiography. Ultrastructure and cell proliferation differed considerably between cultured embryos and noncultured controls. Cultured embryos displayed more dead cells. They were developmentally retarded (predominance of smooth endoplasmic reticulum rather than the age-specific rough endoplasmic reticulum, mitochondria still round to ovoid shaped) and showed nonspecific signs of cells damage (swollen mitochondria and Golgi complex vesicles, increased number of lysosomes). All these features were also present in embryos grown in uterine flushing-supplemented media, but were less pronounced. Cell damage and impaired cell proliferation had affected trophoblast cells more than embryoblast cells. Endoderm could be differentiated only if culture had been started with blastocysts--not with morulae--and seems to require uterine secretions. No significant ultrastructural differences were observed between embryos cultured in synchronous or in asynchronous uterine flushings. Present results indicate that cultured preimplantation rabbit embryos deviate clearly from those grown in vivo and maintain, for some time, a better cellular structure--and probably function--in the presence of uterine flushings than in conventional culture media. Specific abnormal morphologic features related to a particular medium could not be identified.

Animals↗
PubMed1983

Stereologic analysis of the ultrastructure in isolated human T and non-T lymphoid cells. II. Data on blasts in ALL; correlation with immunologic studies and FAB-morphology.

Leukemic cells from 20 cases of acute lymphoblastic leukemia (ALL), examined for T and B markers and classified according to FAB guidelines, were analyzed by electron microscopy. Using stereologic methods a quantitative morphologic characterization of the average blast, assumed to be of clonal origin and thus representative of the whole population, was obtained within each subset. Comparative studies of the ultrastructure of the T, B and non-T, non-B blast on one hand and of the FAB category L1 and L2 on the other were performed. No differences of cell volumes, total cell surface areas, nuclear volumes and surface areas or volumes of nuclear compartments were observed between the immunologically defined subsets. Minor variations were seen in the cellular surface contour, the B blast tending to be more irregular than the T blast. Features most predictive of the immunologic cell type were abundant rough ER in B-derived ALL, increasing with plasmacytoid differentiation, and an increase in dense granules which were often clustered in the vicinity of a well-developed Golgi complex in T ALL. The light microscopic criteria of the FAB classification were nearly all confirmed at the EM-level except that nuclear irregularity was observed to the same degree in both categories. Other differences not related to the FAB scheme were encountered in the volumes of the Golgi complex and of the mitochondrial compartment. Objective criteria as quantitative estimates of cellular structures may contribute to an improved subclassification in ALL.

Adolescent↗
PubMed1991

Influence of repeated lyophilization on the survival of Deinococcus proteolyticus, Micrococcus luteus and Escherichia coli.

Repeated lyophilization of Deinococcus proteolyticus, Micrococcus luteus and Escherichia coli cells results in a successive decrease of their survival. The survival curve is exponential with E. coli and M. luteus, and sigmoidal with a broad shoulder with D. proteolyticus both after repeated lyophilization and after UV- or gamma-irradiation. When cells were subjected to gamma-irradiation after a 20-fold freeze-drying, the corresponding survival curve became exponential without the shoulder. Hence we assume that irradiation and repeated lyophilization afflict the same cellular structures and/or functions.

DNA, Bacterial↗
PubMed2001

The Arp2/3 complex: a central regulator of the actin cytoskeleton.

In recent years the Arp2/3 complex has emerged as a central regulator of actin dynamics, assembling and cross-linking actin filaments to produce a diverse array of cellular structures. Here I discuss our current state of knowledge about this actin-remodelling machine. The predicted structure of the Arp2/3 complex can be directly correlated with its ability to nucleate, cap and cross-link actin filaments. A growing family of Arp2/3 complex activators such as the WASP family, type I myosins, and the newly identified activators cortactin and Abplp tightly regulate this activity within the cell. Localised activation of the Arp2/3 complex produces structures such as lamellipodia or actin patches via a process termed dendritic nucleation. Furthermore, several pathogenic microorganisms have evolved strategies to 'hijack' the Arp2/3 complex to their own advantage. Finally, I discuss some of the questions which remain unanswered about this fascinating complex.

Actin Cytoskeleton↗