bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Extracellular Matrix Proteins on Vascular Smooth Muscle Cell Phenotype
Authors: Hayward I. P. , Bridle K. R. , Campbell G. R. , Underwood P. A. , Campbell J. H. 
Published: September 2002

AbstractThe effect on phenotypic expression of rabbit vascular smooth muscle cells (SMC) of the interstitial matrix proteins collagen I and fibronectin, the basal lamina proteins collagen IV and laminin, and the serum adhesion protein vitronectin was examined in culture. Experiments were performed in foetal calf serum stripped of fibronectin and vitronectin to eliminate their confounding effects. All the proteins promoted adhesion to the plastic culture dish (in a concentration dependent manner) of SMC freshly isolated from the artery wall. These cells had a high volume density of myofilaments (Vvmyo) in their cytoplasm. Laminin was best at maintaining SMC with a high Vvmyo (Vvmyo = 49.8%) followed by collagen IV (41.7%). Cells plated on vitronectin showed the lowest Vvmyo (31.3%). The results support the concept that the SMC basal lamina has a role in maintaining cells in the high Vvmyo phenotype.
AN ICAM‐1 LIKE CELL ADHESION MOLECULE IS RESPONSIBLE FOR CD34 POSITIVE HAEMOPOIETIC STEM CELLS ADHESION TO BONE‐MARROW STROMA
Authors: RAO S. G. A. , CHITNIS V. S. , DEORA A. , TANAVDE V. , DESAI S. S. 
Published: September 2002

AbstractThe microenvironment in the haematopoietic organs plays an important role in regulating and sustaining differentiation and self‐renewal of haematopoietic stem cells. Although crucial for stem cell maintenance and homing, the stromal cell—stem cell interactions are poorly understood. Here we show that an ICAM‐like molecule is responsible for stem cell adhesion to stromal cellsin vitro. The molecule was characterized by a monoclonal antibody 3E10. Immunoblotting results indicated that the molecule had an electrophoretic mobility equal to that of intercellular cell adhesion molecule‐1 (ICAM‐1). Binding inhibition assays, however, showed that inhibition of binding of enriched CD34 cells by 3E10was more prominent in comparison with that of ICAM‐1.
PRIMORDIAL GERM CELL‐DERIVED MOUSE EMBRYONIC GERM (EG) CELLSIN VITRORESEMBLE UNDIFFERENTIATED STEM CELLS WITH RESPECT TO DIFFERENTIATION CAPACITY AND CELL CYCLE DISTRIBUTION
Authors: ROHWEDEL JÜRGEN , SEHLMEYER ULRICH , SHAN JIN , MEISTER ARMIN , WOBUS ANNA M. 
Published: September 2002

AbstractEmbryonic germ (EG) cells of line EG‐1 derived from mouse primordial germ cells were investigated for theirin vitrodifferentiation capacity. By cultivation as embryo‐like aggregates EG‐1 cells differentiated into cardiac, skeletal muscle and neuronal cells accompanied by the expression of tissue‐specific genes and proteins as shown by RT‐PCR analysis and indirect immunofluorescence. In comparison to embryonic stem (ES) cells of line D3 the efficiency of differentiation into cardiac and muscle cells was comparatively low, whereas spontaneous neuronal differentiation was more efficient than in D3 cells. Furthermore, the distribution of cell cycle phases as a parameter for the differentiation state was analysed in undifferentiated EG cells and ES cells and compared to data obtained for embryonic carcinoma (EC) cells of line P19 and differentiated, epithelioid EPI‐7 cells. Flow cytometric analysis revealed similar cell cycle phase distributions in EG, EC and ES cells. In contrast, the somatic differentiated EPI‐7 cells showed a longer G1‐phase and shorter S‐ and G2/M‐phases. Together, our results demonstrate that the differentiation state and capacity of EG cellsin vitroresemble that of totipotent ES cells.
ALPHA‐FETOPROTEIN‐MEDIATED TARGETING—A NEW STRATEGY TO OVERCOME MULTIDRUG RESISTANCE OF TUMOUR CELLS IN VITRO
Authors: MOSKALEVA ELIZAVETA YU. , POSYPANOVA GALINA A. , SHMYREV IGOR I. , RODINA ALLA V. , MUIZHNEK EKATERINA L. , SEVERIN EUGENE S. , KATUKOV VALERY YU. , LUZHKOV YURY M. , SEVERIN SERGEI E. 
Published: September 2002

AbstractThe possibility of overcoming the multidrug resistance of human malignant cells by using doxorubicin conjugated to alpha‐fetoprotein (AFP) was studied. It was shown that this type of antitumour drugs, penetrating the cell by receptor‐mediated endocytosis with AFP as a vehicle, raises the sensitivity of the tumour cells that are resistant due to the expression of the multidrug resistance genemdr1. The sensitivity of antibiotic‐resistant cell lines SKVLB (a human ovarian carcinoma) and MCF‐7 AdrR (a human breast carcinoma) increased by 10‐ and 4‐fold, respectively, when AFP‐conjugated doxorubicin was used. The rationale of using human AFP‐antitumour drug conjugates for the development of new chemotherapeutic approaches to cancer treatment is discussed.
CREATINE KINASE AND CREATINE KINASE ISOENZYME RESPONSES TO HEAT STRESS
Authors: TERBLANCHE S. E. , NEL W. 
Published: September 2002

AbstractDuring this investigation the effects of heat acclimation and exercise on creatine kinase and creatine kinase BB isoenzyme responses in various tissues and serum of male Sprague—Dawley rats were ascertained. Forty rats were randomly divided into two groups of 20 rats each. One group was housed at 22±1°C and the other at 33±1°C. Each of the two groups were subdivided into two subgroups of ten rats each. One subgroup of each group was subjected to a programme of treadmill running of progressive intensity over a period of 6 weeks at the temperature at which it was housed while the other served as a resting control. At the end of the acclimation programme the rats were running at 23m/min for 80min. On the day of sacrifice all four subgroups were subjected to a discontinuous exercise protocol (10min running alternated by a 2‐min rest period; repeated three times) at 30±1°C on a rodent treadmill at 23m/min. The tissues investigated were kidney, heart and muscle. The rats were anaesthetized with pentobarbital sodium (6mg/100g body mass) injected intraperitoneally. The tissues were freeze‐clamped and stored in liquid air until analysed. The body temperature of the four subgroups at the end of the experimental protocol were not significantly different. Acclimation at 33±1°C resulted in significantly lower creatine kinase activity levels. Exercise at 30±1°C also resulted in decreased creatine kinase activity levels in both acclimated groups. A similar trend was observed regarding creatine kinase BB isoenzyme activity levels, especially in kidney.
TRANSCRIPTIONAL ACTIVATION OF HEME OXYGENASE−1 GENE IN MOUSE SPLEEN, LIVER AND KIDNEY CELLS AFTER TREATMENT WITH LIPOPOLYSACCHARIDE OR HEMOGLOBIN
Authors: Oshiro Satoru , Takeuchi Hiroki , Matsumoto Midori , Kurata Shun‐Ichi 
Published: September 2002

Heme oxygenase (HO)−1 catalyzes the conversion of heme to biliverdin, iron and carbon monoxide. HO−1 is induced by many reagents including heme, Hb and lipopolysaccharide (LPS). LPS is known to activate the HO−1 gene in cultured mouse liver and macrophage cells through oxidative activation of NF‐κB. But little is known about the effect of LPS and Hb on the HO−1 gene in living organisms. To study this issue, we examined the HO−1 and its mRNA levels in mouse liver, spleen and kidney after intravenous administration of LPS and Hb. On LPS treatment, the amount of HO−1 and its mRNA increased markedly mainly in mouse spleen, but on Hb treatment the amounts of HO‐1 and its mRNA increased slightly only in liver. Run‐off transcription assay supported the above results and band shift assays also revealed that LPS significantly activates an NF‐κB‐like factor in spleen cells, while Hb slightly activates it in liver cells. According to our previous study, a small amount of Hb injected to mouse is selectively taken up by liver as Hb—haptoglobin complex.These results suggest different pathways for the HO gene activation in mouse organs; one by LPS in spleen cells and the other by Hb in liver cells.
CELL PAIRING AND METHYLATION IN TETRAHYMENA THERMOPHILA ARE ALTERED BY EXOGENOUS HOMOCYSTEINE
Authors: Wolfe Jason , Sasson Shmuel Ben , Ron Arie 
Published: September 2002

AbstractHomocysteine is causally associated with birth defects such as spina bifida, and with premature vascular disease. We have investigated the effects of homocysteine on a cell—cell interaction in a fundamental eukaryotic system, the free‐living ciliate Tetrahymena. Exogenously added homocysteine inhibits cell pairing in a dose‐dependent manner. These effects are exacerbated by adenosine, which by itself has little demonstrable influence on pairing. S ‐adenosylhomocysteine (SAH) is a product of the reaction between adenosine and homocysteine, and is an inhibitor of methyl transferases. We therefore predicted that protein methylation would be significantly inhibited by homocysteine. A direct test of that hypothesis involved a demonstration that incorporation of an isotopically labeled methyl group from methionine into proteins was significantly reduced by homocysteine. The undermethylated proteins are of low molecular weight, and might correspond to known methylatable signaling proteins. We show that vanadate, an inhibitor of protein phosphatase, also inhibits cell pairing, and that the effects of vanadate and homocysteine are additive. This is the first demonstration that methylation and possibly phosphorylation play a regulatory role in cell—cell interactions in ciliates.
DNA‐END BINDING ACTIVITY OF KU IN SYNCHRONIZED CELLS
Authors: Chou Li‐Fen , Chou Wen‐Gang 
Published: September 2002

AbstractThree different types of cells were synchronized by various methods and DNA‐end binding (DEB) activities of Ku were compared with asynchronous controls. In CHO K1 cells synchronized in G1 phase by serum starvation and in S phase by serum refeeding, DEB activity was reduced in S cells but remained unchanged in G1 cells. However, the same type of cells synchronized in G1/S phase by double thymidine block and in S phase by releasing the blockage, have the same DEB activity as asynchronous controls. A similar result was found in RKO and HeLa cells synchronized by the latter method. Arresting cells in mitosis with nocodazole also generated different cell cycle effects. Ku activity was reduced in CHO K1 and RKO cells, but not in HeLa cells after treatment with nocodazole. In phase‐enriched cells separated by centrifugal elutriation, DEB activities were similar at different stages of the cell cycle in all three types of cells. Thus, different synchronization procedures can give very different values of Ku activity in a cell type‐dependent manner. Results from elutriated cells are consistent, and suggest DEB activity of Ku does not change with the cell cycle.
INTERLEUKIN‐6‐INDUCED PRODUCTION OF TYPE II ACUTE PHASE PROTEINS AND EXPRESSION OF junB GENE ARE DOWNREGULATED BY HUMAN RECOMBINANT GROWTH HORMONE IN VITRO
Authors: Derfalvi Beata , Igaz Peter , Fulop Kristof A. , Szalai Csaba , Falus Andras 
Published: September 2002

AbstractGrowth hormone (GH), given therapeutically in many human diseases, is able to modulate the maturation and function of many cells of immune system. The present study demonstrates the effect of human recombinant GH on the production of acute phase proteins (APP) as well as on the gene expression of junB proto‐oncogene on human hepatoma cell line, HepG2. When applied alone GH resulted in an increase in the transcription of junB proto‐oncogene within 30min. The production of α2‐macroglobulin, haptoglobin and fibrinogen was also enhanced by rhGH treatment. However, both IL‐6‐stimulatedjunB gene expression (junB mRNA) and biosynthesis of type II APP (α2‐macroglobulin, fibrinogen, haptoglobin) were strongly inhibited by the GH. The results indicate that GH has a modulatory role in regulating inflammation both in the absence and presence of IL‐6. These findings call for further in vivo studies to determine the potential anti‐inflammatory actions of GH therapy.
ARE CELLS RESCUED FROM ‘LOW DENSITY DEATH’ BY CO‐OPERATION BETWEEN PHOSPHOLIPASES C AND D?
Authors: Rasmussen Morten , Rasmussen Leif 
Published: September 2002

AbstractCells of the ciliate Tetrahymena thermophila die when transferred at low density to a lipid‐free nutritionally complete medium. This death is prevented and they will start to proliferate if protein kinase C is activated and this activation is sustained. We propose that this takes place in two stages. Firstly, the phospholipase C pathway beginning with and specific for phosphatidylinositol leads to the formation of diacylglycerol and inositol tris ‐phosphate. Diacylglycerol activates protein kinase C, and inositol tris ‐phosphate via Ca2+phospholipase D (PLD). Secondly, the protein kinase C response can now be sustained by diacylglycerol produced by phospholipase D, using phosphatidylcholine and phosphatidylserine as substrates. Should this switching from PI‐specific phospholipase C (PLC) to phospholipase D fail, then the cell will die in the course of milliseconds during the minutes following inoculation.
EFFECT OF THE SERINE PROTEASE INHIBITOR N‐TOSYL‐L‐PHENYLALANINE‐CHLOROMETHYL KETONE (TPCK) ON MCF‐7 MAMMARY TUMOUR CELLS GROWTH AND DIFFERENTIATION
Authors: Horman Sandrine , Del Bino Giacinta , Fokan Dominique , Mosselmans Roger , Galand Paul 
Published: September 2002

AbstractPrevious studies from this and other laboratories indicated that the oestrogen‐regulated heat shock protein HSP27 is involved in the control of MCF‐7 cells growth and differentiation, as it also appears to be in other cell types, including osteoblasts and HL‐60 cells. In the latter instance, induction of differentiation is associated with the downregulation of myeloblastin, a serine protease now identified as proteinase 3 (hence its designation as PR3/Mbn), mirrored by an increase in the cellular content of the small heat shock protein HSP27, a substrate to this enzyme. Besides, antisense inhibition of PR3/Mbn production sufficed for inducing HL‐60 cells monocytic differentiation. This prompted us to examine the hypothesis that a post‐translational control on HSP27 levels (and by this on differentiation) by a serine protease might also be operating in human mammary tumour cells. As part of our attempt to evaluate this hypothesis, the present work consisted of testing the effects of a treatment of MCF‐7 cells with the serine protease inhibitor N‐tosyl‐L‐phenylalanine‐chloromethyl ketone (TPCK). Our data show that this resulted in a four‐fold increase in HSP27 content, associated with a 2.5‐fold decrease in growth rate, the formation of cytoplasmic vesicles and increased secretion of 52kDa peptides, identified by Western immunoblot as the isoforms of the oestrogen‐regulated protein, cathepsin D. TPCK only affected growth in MDAMB‐231 cells (in which HSP27 levels are very low and remained below MCF‐7 cells basal levels after treatment) and failed to affect L929 cells, in which the hsp27 gene is silent. This provides circumstantial support for the assumption that effects of TPCK on the MCF‐7 cells phenotype are linked to the associated increase in HSP27 content. Our recent demonstration that MCF‐7 cells do in fact express PR3/Mbn fits with our concept and opens the way to test it directly, using antisense strategy.
INDUCTION OF DNA SYNTHESIS OR APOPTOSIS IN MAMMALIAN NUCLEI BY XENOPUS EGG EXTRACTS THAT FAIL TO SUPPORT THE REPLICATION OF SPERM CHROMATIN
Authors: Logothetou‐Rella Helen , Sun Wei‐Hsin , Brooks Robert F. 
Published: September 2002

AbstractCell‐free extracts of Xenopus eggs are widely used to study DNA replication in higher eukaryotes. However, with Xenopus sperm chromatin as template, it is a common experience that the efficiency of replication varies from extract to extract, for reasons that are unclear. Here we show that the majority of extracts unable to support sperm replication are nevertheless able to induce DNA synthesis in intact mammalian nuclei. Those that do not, induce apoptosis.
DIFFERENCES IN THE MICROTUBULE ORGANIZATION BETWEEN NORMAL AND CML GRANULOCYTES AFTER STIMULATION WITH CHEMOTACTIC PEPTIDE
Authors: Naik Nishigandha , Rigaut Jean‐Paul , Advani Suresh , Bhisey Avinash 
Published: September 2002

AbstractChemotaxis of polymorphonuclear leukocytes (PMNL) from chronic myeloid leukemia (CML) patients followed in a gradient of a chemotactic peptide n‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) is consistently defective in all the phases of the disease. Chemoattractant‐induced polymerization of cytoskeletal proteins (actin and tubulin) plays a major role in regulation of cell shape and cellular motility. To study the role of microtubules in defective chemotaxis, we have compared fMLP‐induced alterations in organization of microtubules in PMNL from CML patients with those from normal subjects by laser confocal microscopy. Our analysis shows differences in microtubule organization between normal and CML PMNL and suggests that both nucleation of new microtubule and elongation of pre‐existing microtubules are essential for PMNL chemotaxis.
GLUCOCORTICOIDS ENHANCE SERUM DEPRIVATION‐ BUT NOT CALCIUM‐INDUCED CYTOTOXICITY IN RAT C6 GLIOMA CELLS
Authors: Morita Kyoji , Wong Dona L. 
Published: September 2002

AbstractWhile glucocorticoids have been shown to exacerbate calcium‐induced neuronal damage, little is known about the effects of these hormones on calcium‐induced damage to glial cells. Here we examine the effect of synthetic glucocorticoid dexamethasone on calcium ionophore A23187 and serum deprivation‐induced damage to rat C6 glioma cells. Treatment of the glioma cells with A23187 reduced cell viability, similar in extent to that observed with serum deprivation. Both A23187 and serum deprivation caused cell damage without degradation of the genomic DNA into nucleosomic fragments. In addition, the reduction in cell viability caused by A23187 was not significantly altered by DEX at concentrations enhancing serum deprivation‐induced cell death. These results suggest that the cytotoxic effect of A23187 on glial cells may be mediated through a mechanism different from that underlying serum deprivation‐induced cell death, and that, in contrast to calcium‐induced neuronal damage, calcium‐induced damage to glial cells is likely to be insensitive to glucocorticoids.
PROTEOLYTIC ACTIVITY IN INTACT SHEETS OF POLARIZED EPITHELIAL CELLS AS DETERMINED BY A CELL‐PERMEABLE FLUOROGENIC SUBSTRATE
Authors: Karlsson Jan‐Olof , Lundquist Jenny , Skoglund Ida , Nilsson Mikael 
Published: September 2002

AbstractThe purpose of the present investigation was to develop a system for continuous evaluation of extralysosomal proteolytic activity and its regulation in polarized epithelial cells. Filter inserts containing a tight monolayer of primary cultured pig thyrocytes were placed in a thermostated aluminium block. The cell‐permeable, fluorogenic calpain and proteasome substrate succinyl‐Leu‐Leu‐Val‐Tyr‐7‐amino‐4‐methylcoumarin was added to the apical buffer and fluorescence changes were continuously measured via the fibre optics of a luminometer held at a fixed distance from the cell layer. Basal proteolytic activity was reduced by 60–70% by the proteasome inhibitor lactacystin. Proteolysis was increased within a few minutes after application of Ca2+‐mobilizing agents (ionomycin, 4‐bromo‐A23187, thapsigargin and maitotoxin). Forskolin and staurosporine also enhanced the proteolytic activity. We conclude that Ca2+mobilization, and possibly also changes of protein kinase activity, rapidly increase non‐lysosomal proteolysis in the intact thyroid epithelium.
CHANGE IN THE ACTIVITY OF LECTINS IN CELL STRUCTURE OF WINTER WHEAT CROWN UNDER THE ACTION OF LOW‐TEMPERATURE HARDENING AND FUSICOCCIN
Authors: Komarova E. N. , Trunova T. I. , Vyskrebentseva E. I. 
Published: September 2002

AbstractHaemagglutinating activity was determined in cell walls and total cell organelles of crown cells of Winter wheat (Triticum aestivum L.) plants. The effect of fusicoccin (FC) was investigated using fractions obtained from plants hardened for 7 days at 2°C and from untreated plants. FC concentration (5×10−7m) increased the frost resistance of the plants. The temporal pattern of lectin activity during hardening could be described by a single‐peak curve. In the cell wall fraction, the highest activity manifested itself after one‐day hardening, and in the fraction of organelles it peaked after five‐days hardening. The carbohydrate specificity of lectins also changed during hardening; cell wall lectins completely lost their capacity for interaction with uridine diphosphoglucose, glucose 6‐phosphate, D‐galactosamine, and N‐acetylglucosamine and the lectins of organelles retained some affinity only for amino sugars. After hardening the test plants, the activity of the lectins increased substantially in the cell walls and plastids, decreased in the nuclei, and was practically flat in mitochondria and microsomes. Consequently, low temperature and FC with their antistress effect improved frost resistance and stimulated the activity of the lectins of some cell structures of the tillering node of winter wheat. A similar action of low temperature and FC in increasing the activity of lectins of plastids was found. Further information was obtained on the subcellular localization of lectins providing additional information on their possible participation in the development of frost resistance of winter wheat.
INFLUENCE OF CYTOSKELETAL AGENTS ON THE RESPIRATORY ELECTRON TRANSPORT PATHWAYS IN THE CELLS OF WINTER WHEAT LEAVES
Authors: Abdrakhimova Y. R. , Khokhlova L. P. , Abdrakhmanova A. F. , Abdrakhimov F. A. 
Published: September 2002

AbstractThe effects of actin and tubulin polymerization inhibitors on the respiratory electron transport pathway activities were investigated using abscisic acid (ABA)‐ and cold‐treated winter wheat seedling leaves. In unstressed control plants, cytochalasin B (15μm) decreased the capacity of the cytochrome pathway, but stimulated the cyanide‐resistant pathway, whereas oryzalin (15μm) produced the opposite effects. Cold hardening (3°C for 7 days) and ABA treatment 30μm changed the respiratory pattern in a similar manner to cytochalasin B but to lesser effects. This points to cold‐ and ABA‐induced reduction in microfilament sensitivity to these drugs and hence stabilization of actin‐dependent processes. In contrast, oryzalin had only weak effects on control samples and its effects were strengthened in the presence of the cytoskeleton‐modifying factors. The data suggest that the potential targets for the agent either increase and/or the degree of involvement of microtubules in the respiratory chain regulation, and therefore that the cytoskeleton can modify the functioning of the respiratory electron transport pathways in winter wheat cells.