bluuebunny/crossref_metadata_2025_split huggingface dataset:
SOMATOSTATIN‐LIKE IMMUNOREACTIVE CELLS IN THE GROUND SQUIRREL RETINA
Authors: LUGO NIDZA , BLANCO ROSA E. 
Published: September 2002

AbstractImmunocytochemical techniques were employed to locate somatostatin (SS)‐containing cells in the retina of the 13‐lined ground squirrel (Spermophilus tridecemlineatus). In normal retinas immunostain was limited to neuronal processes, yet distinctly labeled somata were detected in retinas of animals pretreated with colchicine. Labeled cell bodies were located in the outermost and innermost portions of the inner nuclear layer (INL) and in the ganglion cell layer (GCL). The largest population of SS‐like immunoreactive neurons was found in the innermost INL. These cells were identified as small and medium sized amacrine cells whose soma diameters ranged from 4 to 14μm. A smaller population of immunoreactive cells was observed in the outermost region of the INL. These cells, presumptive horizontal cells, were found mainly in peripheral regions of the retina. Immunoreactive cells in the GCL were of two types: displaced amacrines, and retinal ganglion cells. SS‐positive axons in the optic fiber layer suggest that some of the immunoreactive GCL neurons were ganglion cells, and it is our opinion that these cells belong to a class of associational ganglion cells previously identified in other species.
ANALYSIS OF SPATIAL DISTRIBUTIONS OF CELLULAR MOLECULES DURING MECHANICAL STRESSING OF CELL SURFACE RECEPTORS USING CONFOCAL MICROSCOPY
Authors: RYCHLY JOACHIM , POMMERENKE HAGEN , DÜRR FRIEDA , SCHREIBER ERIK , NEBE BARBARA 
Published: September 2002

AbstractConfocal laser scanning microscopy represents a suitable technique to study the localization of cellular components in three dimension. The authors used this technique to analyse cellular events related to mechanical stimulation of integrin receptors on the cell surface. By performing optical sections the distribution of integrin receptors on the apical surface of an osteoblastic cell was determined. Concerning intracellular compartimentalization of signal transduction events, it was demonstrated that mechanical stimulation of integrins induced their linkage to the cytoskeleton. Cytoskeletally associated proteins like vinculin and talin accumulated in the vicinity of the site where the mechanical stress was applied to integrins on the cell surface. Optical sections revealed that clustering of these proteins proceeded to the base of the cell with gradually decreasing extent. In summary, it was demonstrated that the local distribution of cellular components is an important factor in mechanically induced signal transduction.
GLYCOLIPID GLYCOSYLTRANSFERASE ACTIVITIES DURING EARLY DEVELOPMENT OF XENOPUS: EFFECT OF RETINOIC ACID
Authors: Rossi Federica , Gornati Rosalba , Rizzo Angela M. , Venturini Loretta , Bernardini Giovanni , Berra Bruno 
Published: September 2002

AbstractRetinoic acid (RA) plays an important role in differentiation stage in which it also influences glycoconjugate metabolism. Previous work in our laboratory has shown that treatment with RA modifies glycolipid synthesis and distribution in total Xenopus embryos during development. In this study we have investigated the activity of the following anabolic enzymes involved in glycolipid biosynthesis: sialyltransferase‐1 (SAT‐1), GM3(β1,4)‐N‐acetylgalactosaminyltransferase (GalNAcT‐1) and LacCer(β1,3)N‐acetylglucosaminyltransferase (GlcNAcT‐1). These enzymes are located at the branching point of lactosylceramide (Lc2) metabolism. Enzyme activities were assayed after treatment with different doses of RA added exogenously to the medium during the first 7 days of Xenopus embryo development. Our results show that RA activates GlcNAcT‐1, the enzyme that drives Lc2to the glycolipids of the lacto‐series, and SAT‐1 that inserts Lc2in the ganglio‐series pathway. These data support our previous analysis of glycolipid pattern in Xenopus embryos after RA treatment (Rizzo et al., 1995;Cell Biol Int19: 895–901) indicating a possible correlation between the distribution of glycolipids and the enzymes involved in their metabolism.
Ha‐ ras‐TRANSFORMATION ALTERS THE METABOLISM OF PHOSPHATIDYLETHANOLAMINE AND PHOSPHATIDYLCHOLINE IN NIH 3T3 FIBROBLASTS
Authors: Momchilova A. , Markovska T. , Pankov R. 
Published: September 2002

AbstractCultured NIH 3T3 fibroblasts were employed to investigate the changes in the phospholipid metabolism induced by Ha‐ ras transformation. All phospholipid fractions were reduced in ras ‐transformed fibroblasts except phosphatidylethanolamine (PE). The incorporation of labeled choline and ethanolamine into phosphatidylcholine (PC), PE and their corresponding metabolites were elevated in a similar manner in the transformed cells. The enhanced uptake of choline and ethanolamine correlated with the activation of choline kinase and ethanolamine kinase. Similarly, the uptake of arachidonic, oleic and palmitic acids by PC and PE was higher in ras ‐cells. Acyl‐CoA synthetases, which esterify fatty acid before their incorporation into lysophospholipids, were also activated. However, both CTP:phosphocholine‐cytidylyltransferase and CTP:phosphoethanolamine‐chytidyltransferase were inhibited in the transformed cells. This fact, taken together with the observed activation of choline‐ and ethanolamine kinases, led to accumulation of phosphocholine and phosphoethanolamine, which have been presumed to participate in the processes of tumor development. PC biosynthesis seemed to be carried out through the CDP‐choline pathway, which was stimulated in the oncogenic cells, whereas PE was more likely, a product of phosphatidylserine decarboxylation rather than the CDP‐ethanolamine pathway.
DIFFERENCES IN RAT RBC CYTOSOL INDUCED AFTER IN VIVO PHENYLHYDRAZINE TREATMENT
Authors: Djurkovic Aleksandra , Zaric Jelena , Lušic Marina , Glišin Vladimir , Popovic Zvezdana 
Published: September 2002

AbstractAnalysis of rat red blood cell (RBC) cytosol protein fraction after in vivo phenylhydrazine treatment revealed increased amounts of 68‐kDa protein. This protein is present in trace amounts in normal rat RBC cytosol. We also present data that 68‐kDa protein from RBC cytosol has an identical isoelectric point, partial proteolytic map and immunological determinants as a protein of the same molecular mass from rat exosomes. These data indicate that 68‐kDa protein is normally present in rat RBC cytosol, is exported via exosomes during reticulocyte maturation, and is increased in induced haemolytic anaemia.
INHIBITION OF PROLIFERATION OF CONTAMINATING FIBROBLASTS BY D‐VALINE IN CULTURES OF SMOOTH MUSCLE CELLS FROM HUMAN MYOMETRIUM
Authors: Hongpaisan Jarin 
Published: September 2002

AbstractReplacement of L‐valine with D‐valine in a standard culture medium can selectively inhibit fibroblast proliferation. The aim of the present study was to investigate whether human myometrial cells cultured with D‐valine instead of L‐valine can survive and express their characteristics. Cultured cells (95–98%) maintain expression of the intermediate filament desmin, which is the specific marker for mature muscle cells. By transmission electron microscopy, the cells showed the general morphology of smooth muscle cells in culture. Oxytocin in serum‐free culture medium at 37°C (5min) caused a concentration‐dependent increase in cellular Na and total Ca, and a decrease in K content as determined by X‐ray microanalysis. The percentage of cells cultured with D‐valine responding to oxytocin stimulation was larger than that of cells cultured with L‐valine, suggesting less contamination of smooth muscle cells by fibroblasts in the presence of D‐valine. As shown by measurements with fura‐2, D‐valine‐cultured cells retained the characteristic increase in intracellular free Ca2+ions after oxytocin stimulation.
TISSUES FORMED DURING DISTRACTION OSTEOGENESIS IN THE RABBIT ARE DETERMINED BY THE DISTRACTION RATE: LOCALIZATION OF THE CELLS THAT EXPRESS THE mRNAs AND THE DISTRIBUTION OF TYPES I AND II COLLAGENS
Authors: Li G. , Virdi A. S. , Ashhurst Doreen E. , Simpson A.H.R.W. , Triffitt J. T. 
Published: September 2002

AbstractAn experimental model of leg lengthening was used to study the morphology of, the collagenous proteins present, and the collagen genes expressed in the regenerating tissue following 20% lengthening at four different distraction rates. At a distraction rate of 0.3mm/day (8 weeks distraction), the regenerate consists of intramembranous bone and localized areas of fibrocartilage. At rates of 0.7 (4 weeks) and 1.3mm/day (2 weeks), the bone that grows from the cut ends of the cortical bone is separated by fibrous tissue and cartilage is present. At 2.7mm/day (1 week), only fibrous tissue and sparse bone are present. Type I collagen is present in the matrices around the cells expressing its mRNA and similarly, type II collagen is located around the chondrocytes. Type I collagen mRNA is expressed predominantly by the fibroblasts in the fibrous tissue, the bone surface cells and to a reduced extent by the osteocytes. Type II collagen mRNA is expressed by chondrocytes. The results suggest that osteoblasts and chondrocytes within the regenerate originate from the same pool of progenitor cells, and the differentiation of these cells and the expression of types I and II collagen genes are altered by different rates of distraction. These observations suggest that the optimal rate of distraction in the model is 0.7mm/day.
INHIBITION OF CELL DIVISION BUT NOT NUCLEAR DIVISION BY 1‐ O ‐OCTADECYL‐2‐ O ‐METHYL‐ Sn ‐GLYCERO‐3‐PHOSPHOCHOLINE
Authors: Pushkareva Marina Y. , Janoff Andrew S. , Mayhew Eric 
Published: September 2002

Abstract1‐ O ‐Octadecyl‐2‐ O ‐methyl‐glycero‐3‐phosphocholine (ET‐18‐OCH3) selectively inhibits the growth of cancer cells. Here we show that in some cell types ET‐18‐OCH3and liposome‐associated ET‐18‐OCH3inhibit cell division without concurrent inhibition of nuclear division, leading to multinucleate cell formation, and cell death through apoptosis. Cell cycle analysis revealed that ET‐18‐OCH3‐treated U‐937 cells continued to move through the cell cycle, but many cells were not able to divide and instead accumulated as tetraploid cells or octaploid cells in the G0/G1 phase of the cell cycle. Inhibition of cytokinesis has been shown to be paralleled by activation of U‐937 cells, including upregulation of some cell‐surface markers, acquisition of phagocytic activity, and secretion of tumor necrosis factor (TNF)‐α (Pushkareva et al., 2000). Furthermore, treatment of cells with ET‐18‐OCH3results in the accumulation of apoptotic cells in time‐ and dose‐dependent manner. It is possible that inhibition of cytokinesis may be related to cytoskeletal effects.
INHIBITION OF CYTOKINESIS BY ASBESTOS AND SYNTHETIC FIBRES
Authors: Jensen Cynthia G. , Watson Maureen 
Published: September 2002

AbstractUsing high‐resolution timelapse microscopy, we have followed individual phagocytized fibres through the later stages of division in MeT‐5A human mesothelial cells and LLC‐MK2monkey epithelial cells. The fibres used were crocidolite and chrysotile asbestos, fibrous glass (MMVF), and refractory ceramic fibres (RCF). Long fibres (15–80μm) trapped within the cleavage furrow can partially or completely block cytokinesis. Cells proceed in one of three ways: (1) eventual completion of cytokinesis; (2) incomplete cytokinesis, resulting in two cells joined by a fibre‐containing intercellular channel; or (3) failure of cytokinesis, resulting in a binucleate or trinucleate cell. Two factors associated with fibre‐induced bi/trinucleation are: (1) an initial association between the fibre and the forming daughter nuclei, which is sometimes lost over time, and (2) disintegration of the midbody. The studies suggest that delay of cytokinesis by interzonal fibres can result in bi/trinucleation through the loss of midbody/intercellular bridge proteins that are required for completion of cytokinesis.
EXPRESSION AND PURIFICATION OF BIOLOGICALLY ACTIVE RECOMBINANT QUAIL STEM CELL FACTOR IN E. COLI
Authors: D'Costa Susan , Kulik Michael J. , Petitte James N. 
Published: September 2002

AbstractStem cell factor (SCF) is a multifunctional cytokine involved in hematopoiesis, melanogenesis and gametogenesis. Previous studies have demonstrated that avian SCF is a requirement for the proliferation and survival of various cell types in vivo and in vitro. In the current study, recombinant quail stem cell factor was produced inEscherichia coli using a prokaryotic expression system. SCF was expressed as a fusion protein with a histidine hexamer tag at the N‐terminal end of the protein. Following expression, the protein was purified by affinity chromatography on the Ni‐NTA column. The uninduced and induced protein lysates and the purified protein were separated by SDS‐PAGE and transferred onto nitrocellulose membrane. Western blot analysis with the monoclonal antibody to the histidine tag identified SCF in the induced cell lysates and the purified sample. The recombinant SCF was approximately 22–23kD in size. This protein was generated devoid of the signal peptide, the transmembrane domain, and the intracellular domain and, hence, resembles the soluble form of SCF. Biological activity was assayed using the in vitro survival of E12 chicken dorsal root ganglion‐derived sensory neurons. The addition of recombinant quail SCF improved neuronal survival. Survival (20.6%) was the highest at the 50ng/ml concentration of SCF. The availability of quail SCF will be a valuable tool to further resolve the function of stem cell factor in birds.
GALECTIN‐3 EXPRESSION IN DIFFERENTIATING HUMAN MYELOID CELLS
Authors: Le Marer Nadia 
Published: September 2002

AbstractGalectin‐3 is an endogenous mammalian carbohydrate‐binding protein with affinity for ABH group carbohydrate epitopes and polylactosamine glycans present on cell surface and extracellular matrix glycoproteins. It has been shown to play a role in cell differentiation, morphogenesis, adhesion and cell proliferation regulation. Progenitor cell proliferation in bone marrow depends on stem cell factors including those modulating their adhesion to the bone marrow stroma. The present study shows that the 32kD galectin‐3 is developmentally expressed in human myeloid cells and is strongly upregulated on the cell surface of late mature myeloid cells. Despite the fact that the expression of the galectin‐3 is very low in CD34+ early myeloid cell, a 70kD protein is found by Western blotting using antibodies specific to galectin‐3, exclusively in those cells. Finally, exogenous human recombinant galectin‐3 binds strongly to CD34+ early myeloid cells and emphasizes granulocyte‐colony stimulating factor (G‐CSF) driven proliferation in vitro.
SPEEDING UP KINESIN‐DRIVEN MICROTUBULE GLIDING IN VITRO BY VARIATION OF COFACTOR COMPOSITION AND PHYSICOCHEMICAL PARAMETERS*
Authors: Böhm K. J. , Stracke R. , Unger E. 
Published: September 2002

AbstractSo far, there has been a discrepancy between the velocities of kinesin‐dependent microtubule motility measured in vitro and within cells. By changing ATP, Mg2+, and kinesin concentrations, pH and ionic strength, we tried to find conditions that favour microtubule gliding across kinesin‐covered glass surfaces. For porcine brain kinesin, we found that raising the molar Mg2+/ATP ratio can substantially elevate gliding velocity. Gliding became also faster after temperature elevation or lowering the number of kinesin molecules bound to the glass surface. The highest mean gliding velocity (1.8μm/s±0.09μm/s), approaching velocities measured for anterograde transport in vivo, was achieved by combination of favourable factors (2.5m m ATP, 12.5m m Mg2+, 37°C, 450 kinesin molecules/μm2).
ROLE OF INTERLEUKIN‐6 IN THE PATHOGENESIS OF MULTIPLE MYELOMA
Authors: Gadó Klara , Domján Gyula , Hegyesi Hargita , Falus András 
Published: September 2002

AbstractMultiple myeloma (MM) is a currently incurable disease caused by the proliferation of malignant plasma cells. Although the pathogenesis of the disease still remains unclear, recent research in the biology of MM has produced new insights into the factors that control the growth and survival of myeloma cells. Among the growth factors, interleukin‐6 (IL‐6) has an essential role. Evidence suggests that IL‐6 is not only a growth factor, but also a survival factor in MM, inhibiting apoptosis in myeloma cells. IL‐6 interacts with several factors which are involved in the pathogenesis of MM, such as adhesion molecules, tumour suppressor genes and oncogenes. Considering the essential role of IL‐6, it could serve as a target for new therapeutic interventions. Neutralizing the effect of IL‐6 may result in a regression of tumour progression.
SATELLITE CELL REGULATION FOLLOWING MYOTRAUMA CAUSED BY RESISTANCE EXERCISE
Authors: Vierck Janet , O'Reilly Becky , Hossner Kim , Antonio Jose , Byrne Katherine , Bucci Luke , Dodson Michael 
Published: September 2002

AbstractIt is generally accepted that the primary mechanisms governing skeletal muscle hypertrophy are satellite cell activation, proliferation, and differentiation. Specific growth factors and hormones modulate satellite cell activity during normal muscle growth, but as a consequence of resistance exercise additional regulators may stimulate satellite cells to contribute to gains in myofiber size and number. Present knowledge of the regulation of the cellular, biochemical and molecular events accompanying skeletal muscle hypertrophy after resistance exercise is incomplete. We propose that resistance exercise may induce satellite cells to become responsive to cytokines from the immune system and to circulating hormones and growth factors. The purpose of this paper is to review the role of satellite cells and growth factors in skeletal muscle hypertrophy that follows resistance exercise.
SPECTRIN‐LIKE PROTEINS IN PLANT NUCLEI
Authors: De Ruijter Norbert C. A. , Ketelaar Tijs , Blumenthal Sonal S. D. , Emons Anne Mie C. , Schel Jan H. N. 
Published: September 2002

AbstractWe analysed the presence and localization of spectrin‐like proteins in nuclei of various plant tissues, using several anti‐erythrocyte spectrin antibodies on isolated pea nuclei and nuclei in cells. Western blots of extracted purified pea nuclei show a cross‐reactive pair of bands at 220–240kDa, typical for human erythrocyte spectrin, and a prominent 60kDa band. Immunolocalization by means of confocal laser scanning microscopy reveals spectrin‐like proteins in distinct spots equally distributed in the nucleoplasm and over the nuclear periphery, independent of the origin of the anti‐spectrin antibodies used. In some nuclei tracks of spectrin‐like proteins are also observed. No signal is present in nucleoli. The amount and intensity of signal increases when nuclei were extracted, successively, with detergents, DNase I and RNase A, and high salt, indicating that the spectrin‐like protein is associated with the nuclear matrix. The labelling is similar in nuclei of various plant tissues. These data are the first that show the presence and localization of spectrin‐like epitopes in plant nuclei, where they may stabilize specific interchromatin domains.
CYTOKINES IN DISEASES OF THE ENDOCRINE SYSTEM
Authors: Igaz Peter , Falus András , Gláz Edit , Rácz Károly 
Published: September 2002

AbstractCytokines, the polypeptide mediators of the immune system, were shown to exert numerous actions on endocrine functions. Bidirectional links based on the sharing of mediators and receptors between the immune and neuroendocrine systems lead to the concept of the immune—neuroendocrine system that seems to constitute an important and sophisticated regulatory system in the homeostasis. Several cytokines were found to be involved in the pathogenesis of diseases of the endocrine system. In this brief review, we attempt to present a general outline of the local actions of cytokines on cells of endocrine organs with an emphasis on disease etiology (pituitary tumours and autoimmune endocrine diseases in particular).
CATALASE ACTIVITY IN HUMAN ERYTHROCYTES: EFFECT OF PHENOXYHERBICIDES AND THEIR METABOLITES
Authors: Bukowska Bozena , Chajdys Anna , Duda Wirgiliusz , Duchnowicz Piotr 
Published: September 2002

AbstractThe effects of exposure to different concentrations of phenoxyherbicides and their metabolites were studied in human erythrocytes, with particular attention to catalase (CAT—EC. 1.11.1.6— hydrogen peroxide: hydrogen peroxide oxidoreductase). 4‐chloro‐2‐methylphenoxyacetic acid (MCPA), 2,4‐dimethylphenol (2,4‐DMP) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) did not affect CAT activity, but 2,4‐dichlorophenol (2,4‐DCP) and 2,4,5‐trichlorophenol (2,4,5‐TCP) decrease its activity, the latter being the more inhibitory.
PERSISTENT FUSION PORES BUT TRANSIENT FUSION IN ALVEOLAR TYPE II CELLS
Authors: Dietl Paul , Haller Thomas 
Published: September 2002

AbstractThe release of vesicle contents following exocytotic fusion is limited by various factors including the size of the fusion pore. Fusion pores are channel‐like, narrow structures after formation and proceed through semi‐stable states (‘fusion pore flickering’), unless they fully expand (full fusion) or close again (transient fusion). Partial release of vesicle contents may occur during transient fusion, which was described to last between milliseconds and seconds, depending on the size of the vesicle. We studied fusion pores in a slow‐secreting lung epithelial cell (type II cell) using fluorescence staining of vesicle contents (surfactant) and fluorescence recovery after photobleaching (FRAP). Surfactant is a lipidic material, which is secreted into the alveolar lumen to reduce the surface tension in the lung. We found release of surfactant to be a slow process, which can last for hours. Accordingly, fusion pores in these cells are stable structures, which appear to be a barrier for release. FRAP measurements suggest that transient fusions occasionally take place in these long‐lasting fusion pores, resulting in partial release of surfactant into the extracellular space. These data suggest that postfusion mechanisms may regulate the amount of secreted surfactant.