bluuebunny/crossref_metadata_2025_split huggingface dataset:
REGULATION OF ION TRANSPORT BY P2UPURINOCEPTORS AND α2A ADRENOCEPTORS IN HT29 CELLS
Authors: ZHANG WEI , ROOMANS GODFRIED M. 
Published: October 2002

AbstractX‐ray microanalysis was applied to investigate ion transport mediated by P2Upurinoceptors and α2A adrenoceptors as well as their interaction in the regulation of the intracellular elemental concentration in HT29 cells. In response to ATP, HT29 cells showed a decrease of intracellular Cl, Na and an increase in Ca. A similar result was observed with UTP, but UTP appeared to be more potent than ATP. On the other hand, UK14,304, an α2receptor agonist, was found to be capable of reversing the action of both UTP and ATP on ion secretion, and caused a clear increase in intracellular Na and Cl. Moreover, treatment of cells with UK14,304 before exposure to UTP did not induce a decrease in Cl and Na, suggesting that UK14,304 blocks the action of UTP. The secretory effect of UTP was also blocked by NPPB, a chloride channel blocker, and alloxan. Chelation of extracellular Ca with EGTA abolished ion response to UTP. These results suggest that since inhibition of the intracellular cAMP system and chelation of Ca2+can block the nucleotide‐induced chloride secretion, the ATP and UTP‐induced chloride secretion can be mediated via both cAMP‐dependent and Ca2+‐dependent pathways.
A RAPID BIOASSAY TO DETECT MYCOTOXINS USING A MELANIN PRECURSOR OVERPRODUCER MUTANT OF THE CILIATETETRAHYMENA THERMOPHILA
Authors: GONZÁLEZ ANA MARTÍN , BENÍTEZ LAURA , SOTO TRINIDAD , DE LECEA RODRIGUEZ JOSEFINA , GUTÍERREZ JUAN CARLOS 
Published: October 2002

AbstractFour different mycotoxins (patulin, T‐2 toxin, diacetoxyscirpenol and roquefortine) were used to study growth inhibitory effects on a melanin precursor overproducer mutant of the ciliateTetrahymena thermophilaThis strain is especially sensitive to diacetoxyscirpenol and T‐2 toxin. The secretion capacity of melanin precursors into the culture medium by this mutant and its biosensor capacity are very useful characteristics to elaborate a rapid bioassay to detect some specific mycotoxins.
TREATMENT OF RAT PROXIMAL AND DISTAL COLONIC CELLS WITH SODIUM ORTHOVANADATE ENHANCES THEIR ADHESION AND SURVIVAL IN PRIMARY CULTURE
Authors: KAEFFER B. , BÉNARD C. , BLOTTIÈRE H.M , CHERBUT C. 
Published: October 2002

AbstractWe have studied the effect of sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, on primary cultures of colonocytes and stromal cells. Everted proximal and distal colonic tissue of adult rats were disintegrated by a collagenase/dispase solution for 60 min at 37°C to prepare viable gland fragments and isolated cells. Cell preparations were inoculated onto plastic substratum or cytodex‐3 microcarriers in a defined maintenance medium or in 1% fetal calf serum media. Incorporation of sodium orthovanadate (≥50 μm) in these media constantly enhanced the survival (cell enumeration and trypan blue exclusionP<0.05) and the adhesion (up to four‐fold by crystal violet staining,P<0.01) of colonocytes (characterized by cytokeratin‐18, transforming growth factor‐α or alkaline phosphatase expression) and stromal cells. Removal of sodium orthovanadate from culture media restored cellular death processes. Incorporation of 10 mmn‐butyric acid did not promote cell adhesion and survival except for distal cells exposed to 2 mm sodium orthovanadate. Besides studies in the regulation of anoikis in primary culture, the model will help to assay the influences of dietary and growth factors on the biology of non‐cancerous colonic cells.
IL‐1 MODIFIES SYSTEM A TRANSPORT ACTIVITY IN HUMAN RHEUMATOID SYNOVIAL CELLS
Authors: LE MAIRE VALÉRIE , HERNVANN ALAIN , LE MARECHAL HERVÉ , EKINDJIAN OHVANESSE G. , AUSSEL CHRISTIAN 
Published: October 2002

AbstractGiven the importance of interleukin‐1 in both rheumatic diseases and the modulation of cell metabolic activities, we studied the action of this cytokine on the neutral amino acid transport A system on rheumatoid synovial cells. In these cells IL‐1 (1ng/ml) induced amino transport stimulation from 5min to 5h. This effect was obtained only after a starvation period. No concentration‐related effect was found for IL‐1‐stimulated MeAIB uptake, and the IL‐1‐mediated MeAIB uptake stimulation is independent of protein synthesis. Neosynthesis or post‐translational maturation of protein transport is a prerequisite for obtaining this effect. In conclusion, rheumatoid synovial cells exhibit a higher sensitivity for IL‐1 than osteoarthritic ones, probably related to their intense metabolic activity.
THE EFFECT OF ENVIRONMENTAL ANEUPLOIDY‐INDUCING AGENTS ON THE MICROTUBULE ARCHITECTURE OF MITOTIC MERISTEMATIC ROOT CELLS INHORDEUM VULGARE
Authors: VOUTSINAS G. , ZARANI F.E , KAPPAS A. 
Published: October 2002

AbstractMicrotubules are the prime components involved in chromosomal segregation, their functional accuracy ensuring maintenance of the normal karyotype in the progeny. Chemically‐induced disruption of microtubules during mitosis can lead to aneuploidy. In this study, seven environmental chemicals, i.e. cadmium chloride (CD), econazole nitrate (EZ), benomyl (BM), thiabendazole (TB), griseofulvin (GF), thimerosal (TM) and hydroquinone (HQ), were tested for their ability to induce microtubule disruption in mitotic meristematic root cells of the higher plantHordeum vulgarewith the use of anti‐tubulin indirect immunofluorescence microscopy. All chemicals tested in this study, with the exception of TB and HQ, produced modifications in the morphology of microtubule organization and reduced the fidelity of the spindle apparatus inHordeum vulgare
MAJOR LAMININ‐BINDING AND F‐ACTIN‐LINKED GLYCOPROTEINS OF NEUTROPHILS
Authors: KERESZTES MARGIT , LAJTOS ZSUZSA 
Published: October 2002

AbstractTwo major EHS‐laminin‐binding membrane glycoproteins—with apparent molecular masses of 50kD and 18kD—were shown by protein blotting in membrane fractions of porcine neutrophils. These galectin‐like glycoproteins (binding probably via the N‐acetyllactosamine sequences to laminin) could also be detected by labelled F‐actin in protein blots. Following 35min adhesion to the plastic surface, the relative amount of the 18kD protein increased considerably in the light (plasma membrane) and in the dense (intracellular) membrane fractions of the attached cells; the 50kD polypeptide (identified as a CD14‐like protein) seemed to accumulate characteristically in the dense membrane fraction. These observations imply that direct connections could be formed between membrane glycoproteins and microfilaments during cell—substrate adhesion which may be preceded by enhanced cell surface targeting of certain adhesion receptors.
ROLB EXPRESSION PATTERN IN THE EARLY STAGES OF CARROT SOMATIC EMBRYOGENESIS
Authors: DI COLA ALESSANDRA , POMA ANNA , SPANÒ LAURA 
Published: October 2002

AbstractThe pattern of expression of therolBgene, derived from the T‐DNA of the plant pathogenAgrobacterium rhizogenes, has been investigated during the early stages of somatic embryo formation in suspension cultures of carrot (Daucus carotaL.). The reporter geneGUS(Escherichia coliβ‐glucuronidase), under transcriptional control of full‐lengthrolB promoter region, has been utilized in order to evaluate both qualitative and quantitative variations in the expression pattern. Fluorimetric measurements point to the developmental regulation of the gene, while results from histochemical analysis indicate that the promoter ofrolBis firstly activated in the central (core) region of the globular embryos.
CELL—CELL CONTACTS ACCELERATE CELL COLONY GROWTH IN SPARSE CULTURES OF CHICK EMBRYO FIBROBLASTS
Authors: GASPARIAN G. , SARKISSIAN N. , SAYADIAN A. , GRIGORIAN R. 
Published: October 2002

AbstractThere is no cell proliferation in very sparcely plated chick embryo cell cultures. Substituting conditioned medium or adding of ethanol‐fixed homologous cells to the cultures accelerates cell colony growth. The mechanism for the mitogenic action of fixed cells is considered to be the contact stimulation of cell proliferation, and addition of extra cells to sparse culture is believed to mimic the cell micro‐environment existing in subconfluent cultures. The role of diverse cell—cell contacts in cultured cell growth regulation is discussed. The procedure used (addition of ethanol‐fixed cells) may improve normal cell cloning techniques.
HISTONES AS EXTRACELLULAR MESSENGERS: EFFECTS ON GROWTH HORMONE SECRETION
Authors: BROWN O. A. , SOSA Y. E. , GOYA R. G. 
Published: October 2002

AbstractHistones display hormone‐like properties when present in extracellular fluids. The authors report that histones H2A and H2B possess growth hormone (GH)‐releasing activityin vitroand describe the specificity and signal transduction pathways involved in these effects. Perfused and incubated rat pituitary cells were used in different sets of experiments and GH release was measured by radio‐immunoassay (RIA). Perfusion of cells with 30μmhistone H2A or H2B, generated significant GH secretory responses. Cells incubated with histone H2A showed a dose‐ and time‐dependent stimulatory effect on GH release which was blocked by peptide MB35, a synthetic fragment of histone H2A. Incubation of pituitary cells with the GH secretagogue GHRP‐6, and histones revealed an additive release of GH, whereas GHRH and histones revealed a synergistic effect. The basic peptide poly‐Lys did not mimetize the action of histones. Both EGTA and the protein kinase C inhibitor trifluoperazine, but not the calcium ionophre A23187, were able to reduce significantly the GH response of somatotrophs to histones. Pituitary cell incubation with 30μmforskolin alone or in the presence of H2A or H2B, stimulated GH release in the same magnitude. The results confirm previous evidence that histones may act as hypophysotropic signals and suggest, although do not prove, that this activity is receptor dependent. Calcium‐ and diacylglycerol‐associated pathways participate in these effects.
SODIUM BUTYRATE STIMULATES THE SYNTHESIS OF FIREFLY LUCIFERASE IN TRANSFECTED CHO CELLS BUT LEVELS OF BiP CHAPERONE ARE UNAFFECTED
Authors: Winge Ingeborg , Pryme Ian F. 
Published: October 2002

AbstractA stably transfected CHO cell line (LUCLEAD) was used where the coding region of native Firefly luciferase was linked to the 3′‐UTR of the bovine growth hormone, and the 5′‐nucleotides coding for the albumin signal peptide were linked to the N‐terminal end of the luciferase coding region. Incubation of cells with 1 or 2mM sodium butyrate (SB) for 72h had no effect on cell growth since cultures reached confluency at the same time as control cells. Although cell cultures incubated with SB at a concentration of 4mM were only about 60% confluent the luciferase content was about 5‐fold higher than that in control cells. Cells incubated with either 1 or 2mM SB showed intermediate levels of luciferase content. The amount of the chaperone BiP in the cells was not affected by incubation with SB. The results indicate that SB can be used to effectively promote synthesis of recombinant luciferase.
BCL‐2 DOES NOT CONTROL PROGRAMMED CELL DEATH IN THE IPLB‐LdFB CELL LINE FROM THE INSECT LYMANTRIA DISPAR
Authors: Ottaviani Enzo , Malagoli Davide 
Published: October 2002

AbstractIn the insect Lymantria dispar cell line IPLB‐LdFB the presence of a Bcl‐2‐like molecule has been demonstrated. The Western blot analysis performed on the cells incubated with 2‐deoxy‐D‐ribose (dRib), an apoptotic inducer, revealed that, in comparison with the control, the Bcl‐2 expression was unaffected. Furthermore, incubation of the insect cells with an anti‐Bcl‐2 polyclonal antibody inhibited the apoptotic effect induced by dRib, and provoked mitochondrial membrane depolarization without any apoptotic phenomena. Similar behaviour was observed using the K+ ionophore valinomycin. From these findings, we hypothesize that the L. dispar Bcl‐2‐like protein is essential for maintenance of the mitochondrial membrane potential, but not, as usually thought, for the regulation of programmed cell death.
CORRELATION BETWEEN CELL SURVIVAL, CLONOGENIC ACTIVITY AND MICRONUCLEI INDUCTION IN DMBA‐OC‐1R CELLS TREATED WITH IMMUNOSPECIFIC ALBUMIN MICROSPHERES CONTAINING CISPLATIN AND 5‐FLUOROURACIL
Authors: Truter Ernest J. , Santos Aldina S. , Els Willem J. 
Published: October 2002

AbstractAn ideal chemotherapeutic strategy would be to deliver a high concentration of drug that would be released in sustained small amounts from targeted microspheres to effectively kill only the tumour cells and thus reduce toxicity to normal tissue. Clonogenic and cell survival growth curve assays, as well as the micronucleus assay, were used to determine the feasibility of employing targeted immunomicrospheres in the treatment of cancer. Cells of a rodent ovarian carcinoma cell line, were exposed to cisplatin and 5‐fluorouracil, either as free drug or encapsulated in albumin microspheres that were either conjugated to monoclonal antibodies or not. In cell survival growth curve assays, cell survival was reduced to 1.2% of the control when cells were treated with drug‐containing immunomicrospheres. 3.2‐fold more micronuclei were found in those cells that had been exposed to the drugs in immunomicrospheres than in those subjected to untargeted microspheres. All three assays demonstrated that the targeted immunomicrospheres were more effective in delivering cisplatin and 5‐fluorouracil directly to the cells than the unconjugated microspheres, thus suggesting that targeted chemotherapy might be a more effective option in the treatment of cancer.
EXPRESSION AND POST‐TRANSLATIONAL MODIFICATION OF HUMAN 4‐HYDROXY‐PHENYLPYRUVATE DIOXYGENASE
Authors: Aarenstrup Lene , Falch Anne‐Marie , Jakobsen Kirsten K. , Neve Søren , Henriksen Linda Ø , Tommerup Niels , Leffers Henrik , Kristiansen Karsten 
Published: October 2002

Abstract4‐hydroxyphenylpyruvate dioxygenase (HPD) (EC 1.13.11.27) is a key enzyme involved in tyrosine catabolism. Congenital HPD deficiency is a rare, relatively benign condition known as hereditary type III tyrosinemia. The severe type I tyrosinemia, caused by a deficiency of fumarylacetoacetate hydrolase which functions downstream of HPD in the tyrosine degradation pathway, is often associated with decreased expression of HPD, and interestingly, inhibition of HPD activity seems to ameliorate the clinical symptoms of type I tyrosinemia. The HPD gene was previously mapped to the chromosomal region 12q24→5;qter. In the present study high‐resolution chromosome mapping localized the HPD gene to 12q24.31. DNase I footprinting, revealed that four regions of the HPD promoter were protected by rat liver nuclear proteins. Computer‐assisted analyses suggested that these elements might bind Sp1/AP2, HNF4, HNF3/CREB, and C/EBP, respectively. In transient transfection experiments, the proximal 271bp of the promoter conferred basal transcriptional activation in human Chang cells. Sequences in intron 1 were able to enhance the activity of this basal promoter. Finally, vaccinia virus‐based expression provided evidence that HPD is subject to phosphorylation, and furthermore, allowed mapping of the HPD protein in the human keratinocyte 2D database.
Reinterpretation of Late Quaternary Sediment Chronology of Lake Biwa, Japan, from Correlation with Marine Glacial-Interglacial Cycles
Authors: Meyers Philip A. , Takemura Keiji , Horie Shoji 
Published: October 2002

AbstractA review of published stratigraphic records of pollen, sediment grain size, diatoms, and organic matter composition from Lake Biwa, Japan, identifies four pre-Holocene episodes of milder climate, increased surface runoff, and enhanced aquatic productivity, indicating intervals of warmer and wetter conditions which are interpreted as being interglacial. Correlation of these episodes to times of marine interglacial periods revises the age scale of the Lake Biwa sediment sequence which has been based on fission-track dating. The revised chronostratigraphic scale proposes an age of ca. 430,000 yr B.P. for the base of the 250-m-thick T Bed instead of the former age of ca. 700,000 yr B.P.
Alluvial Soil Chronosequence in the Inner Coastal Plain, Central Virginia
Authors: Howard Jeffrey L. , Amos Dan F. , Daniels W. Lee 
Published: October 2002

AbstractA chronological sequence of soils formed on a series of alluvial depositional surfaces ranging in age from late-middle Miocene to late Pleistocene was characterized to clarify soil-geomorphic relations and provide a basis for allostratigraphic subdivision of the inner Coastal Plain. On Quaternary river terraces, Ultic Hapludalfs containing abundant weatherable mineral species and clast types are estimated to have formed in 60,000-120,000 yr, whereas Typic Hapludults greatly depleted in weatherable minerals and showing strong weathering of clast types are estimated to be 700,000-1,600,000 yr old. Typic Paleudults with incipient plinthite, duripan, and ferricrete development characterize interfluves that have been little eroded since early Pliocene time (3.4-5.3 myr ago). Typic-Plinthic Paleudults with intense weathering of siliceous clasts and moderate to strong duripan and ferricrete development are found on surfaces that formed near the beginning of late Miocene time (10.8-13.0 myr ago). Chemical weathering in the chronosequence may be classified into three progressive stages: (1) decomposition of unstable sand- and silt-sized minerals into a mixed (stable + unstable) clay-mineral suite (stable Fe + Al/Si bulk chemical composition, < 106 yr); (2) transformation of mixed clay-mineral suite into a stable suite (increasing Fe + Al/Si bulk chemical composition, 106 - 107 yr); and (3) transformation of stable suite into ultrastable clay-mineral suite (increasing Fe/Si bulk composition, > 107 yr). Not all soil properties show unidirectional development, nor is a steady state of pedon development observed even after approximately 107 yr of chemical weathering. Soil development in the chronosequence is episodic. The transition from one phase to the next is marked by a change in rate, and sometimes a reversal in the direction, of development of one or more soil properties.
Reconstruction of Holocene Precipitation Patterns in Europe Using Pollen and Lake-Level Data
Authors: Guiot Joël , Harrison Sandy P. , Prentice I. Colin 
Published: October 2002

AbstractLake-level data can be used to refine palaeoclimate reconstructions based on pollen data. This approach is illustrated for the European Holocene. Estimates of P-PET (precipitation minus potential evapotranspiration) were first inferred from modern pollen analogues. The pollen-based estimates were then compared with the status of lakes within a 5° radius. Analogues with P-PET anomalies inconsistent with the lake-level changes were rejected. The "constrained" sets of analogues were used to estimate continental-scale patterns of annual mean temperature and annual precipitation at 3000-yr intervals. Estimated temperature anomalies differed only slightly from the unconstrained reconstructions. Estimated precipitation anomalies, however, showed improved spatial coherence and increased regional contrast and were occasionally reversed in sign. The effect of the constraint was to impose a rational selection among almost equally similar modern pollen analogues with similar temperatures but widely varying moisture regimes. The resulting maps showed clear, spatially coherent patterns of change in precipitation as well as temperature, suitable for comparison with climate-model results. Further improvement of these maps will become possible as a more extensive coverage of lake-level data is obtained.
Holocene Paleofloods of the Ross River, Central Australia
Authors: Patton Peter C. , Pickup Geoff , Price David M. 
Published: October 2002

AbstractThe rivers of central Australia rise in the MacDonnell Ranges and flow out across broad, low-relief plains into the surrounding desert. The stratigraphy of the Ross River plain records the areal extent and frequency of Holocene floods. This floodout plain is underlain by deeply weathered alluvial deposits, characterized by red earth soils dated by thermoluminesence at >59,000 yr. This old alluvium is covered by a sheet-like deposit of very silty sand of probable eolian origin dated by thermoluminesence at 9200 ± 900 yr. The oldest Holocene alluvium occurs as broad, low-relief bars and levee deposits flanking the modem channel and as low-relief long-wavelength bedforms that fan out across the plain. This deposit resulted from a flood flow, up to 10 km wide, that covered the entire plain. Evidence for several large floods between 1500 and 700 yr B.P. is also preserved in a 500- to 1500-m-wide paleochannel. Thus, the surface features on the floodout plains are the product of a few rare large flood events. This paleohydrologic record is additional evidence of the dynamic nature of the hydrometerological regime of central Australia.
Evidence Suggesting That Methods of Rock-Varnish Cation-Ratio Dating Are neither Comparable nor Consistently Reliable
Authors: Bierman Paul R. , Gillespie Alan R. 
Published: October 2002

AbstractUsing samples from a prehistoric quarry site in the Mojave Desert, we tested and compared the two principal methods of rock-varnish cation-ratio dating, analysis of rock-varnish scrapings (R. I. Dorn, 1983, Quaternary Research 20, 49-73 and 1989, Physical Geography 13, 559-596) and analysis of rock varnish in situ (C. D. Harrington and J. W. Whitney, 1987, Geology 15, 967-970). Because we found no consistent relationship between the varnish cation ratio (K + Ca)/Ti, and the relative age of the varnish, neither method could be used to "cation-ratio date" the underlying chert artifacts. Moreover, in situ analyses yielded systematically higher cation ratios and lower Ti abundances than bulk analyses of scraped varnish or microprobe analyses of varnish in cross section. Our results, when considered along with other recently published evidence, indicate that these two methods of varnish chemical analysis and cation-ratio dating may not be comparable, nor consistently reliable, chronometers.
Heterogeneity, Correlatives, and Proposed Stratigraphic Nomenclature of Hayes Tephra Set H, Alaska
Authors: Riehle James R. 
Published: October 2002

AbstractSeveral Holocene tephra deposits of Hayes volcano constitute a marker horizon in southern and east-central Alaska. Their identification is aided by high amphibole/pyroxene ratio and biotite in trace amounts, unique among Holocene tephra deposits of the region. However, correlations are obscured by chemical heterogeneity of the glass which occurs at a scale less than the size of a lapilli. Single-shard analyses confirm that the heterogeneity is due neither to fractionation nor to plagioclase microlites. The heterogeneity may be due to mixing of magmas prior to eruption. It is proposed that the deposits be informally called Hayes tephra set H.